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description | The invention relates to a limiting device for limiting the cross-section of a beam of electromagnetic rays as disclosed in the introductory part of claim 1, as well as to an analysis device for the examination of material samples by means of electromagnetic radiation as disclosed in the introductory part of claim 12. For the analysis of material samples by means of electromagnetic radiation, for example, by means of X-rays, it is necessary to limit the cross-section of the beam which is incident on the sample as well as that of the beam which emanates from the sample so as to be incident on a detector; such beam limiting is necessary to avoid irradiation of parts which are situated to the side of the optical path, for example, parts of a sample holder, and to prevent radiation reflected by such parts or scattered or secondary radiation arising at that area from reaching the detector because such information would falsify the analysis result. For example, in the case of an energy-dispersive measurement all photons incident on the detector are counted, regardless of whether such photons originate directly from the sample to be examined or from surrounding components. Therefore, it is an object of the invention to enable an as genuine as possible measuring result to be obtained. This object is achieved in accordance with the invention by means of a limiting device as disclosed in the characterizing part of claim 1 as well as by means of an analysis device as disclosed in the characterizing part of claim 12. Advantageous embodiments of the invention are disclosed in the dependent claims 2 to 11 and 13 to 16. The second beam cross-section limiter, comprising a component extending at an angle relative to the longitudinal direction of the first beam cross-section limiter in accordance with the invention enables limitation of the beam cross-section of a beam which is incident on a sample as well as of a beam which is reflected thereby or produced by scattering or secondary processes and emanates therefrom. Unlike a two-dimensional diaphragm, whose entire cross-section is exposed to the incident beam and whose entire edge zone, therefore, produces reflected rays or secondary radiation, that is, by interaction of the incident rays with the diaphragm material, the second beam cross-section limiter enables partial masking of the first beam cross-section limiter. The interaction processes of the incident beam with the first beam cross-section limiter which is planar as a diaphragm, are thus limited to a part thereof. Consequently, fewer disturbing secondary rays are produced overall. It is at the same time possible for the second beam cross-section limiter to shield another region of the first beam cross-section limiter from the detector limiter in such a manner that reflected radiation or scattered or secondary radiation arising in this region cannot reach the detector because it is stopped by the second beam cross-section limiter. When the first beam cross-section limiter comprises two mutually intersecting passage apertures for rays, it can be used as an integral component for an incident beam as well as for a beam which is emitted by a sample or a target. For example, when the second beam cross-section limiter is arranged so as to extend perpendicularly thereto in such a manner that it intersects the passage apertures of the first beam cross-section limiter at its edges of intersection, defined limiting edges are formed, that is, along its entire contour, for an incident beam or a beam returned by the sample or a target, the respective passage apertures of the first beam cross-section limiter and the passage aperture of the second beam cross-section limiter advantageously forming each time in projection substantially a circle or a similar regular geometrical contour configuration while the incident beam enters perpendicularly to the contour area thus formed between the first passage aperture of the first beam cross-section limiter and the passage aperture of the second beam cross-section limiter and the exit beam emanates in conformity with the defined contour between the second passage aperture of the first beam cross-section limiter and the passage aperture of the second beam cross-section limiter. The incident beam as well as the returned beam then encounter defined boundaries along their entire circumference, so that for both beams a geometrically regular contour configuration of the exposed region can be formed, that is, notably a circle. Rays which are outside this region are reliably stopped. It is particularly advantageous to configure the contour of the passage aperture in such a manner that the incoming beam irradiates merely edge zones of its passage aperture provided for the entry and that those edge zones of the second passage aperture of the first beam cross-section limiter wherefrom secondary rays could mingle with the returned beam, are not exposed by the measuring beams. At the same time it is particularly advantageous that the radiation arising at the first passage window of the first beam cross-section limiter, notably secondary radiation which is caused by interaction processes and is emitted in the direction of the emanating beam, is shielded by the second beam cross-section limiter so that it cannot reach the detector. Overall the number of photons which arise from secondary processes and reach the detector is thus significantly reduced, so that the measuring result is significantly enhanced. The present embodiment will be described in detail with reference to the beam path shown in FIG. 1. It will be evident that other beam paths and radiation sources as well as other arrangements of samples to be examined are also feasible. The configuration shown in FIG. 1 utilizes a radiation source 1, in this case being an X-ray source, and a first beam 3 emanates from the exit window 2 thereof, which beam is conducted to a target 4 so as to obtain the characteristic radiation of the target material in the beam which is reflected thereby or formed by interaction processes. The beam 5, therefore, serves as a measuring beam and is partly reflected by the sample 6 to be examined, the angle of incidence usually being equal to the angle of reflection. Moreover, scattering and secondary rays are caused by interaction processes between the measuring beam 5 and the sample 6; these scattering and secondary rays are taken up in the beam 7 which emanates from the sample 6 and is directed onto the detector 8. As is shown in FIG. 8 and as will be described in detail hereinafter, the limiting device 9 for limiting the cross-section in accordance with the invention is arranged between the incident measuring beam 5 and the beam 7 to the detector in front of the sample 6. The limiting device 9 for the beam cross-section of the electromagnetic rays includes a first beam cross-section limiter 10 which extends in a plane 11 and bounds two mutually intersecting passage apertures 12, 13 in the present embodiment. The limiting device 9 also includes a second beam cross-section limiter 14 which extends in a plane 15 in the present embodiment, which plane is directed perpendicularly to the first plane 11 of the first beam cross-section limiter 10. It is not necessary that the elements 14 and 10 extend perfectly perpendicularly to one another; it may suffice when the element 14 instead comprises a longitudinal component which extends at an angle relative to the plane 11 of the first beam cross-section limiter 10. The perpendicular orientation offers the advantage that the use of a single structural component for the second beam cross-section limiter 14 enables an effect to be exerted on the incident beam 5 as well as a similar effect on the exit beam 7. This effect can in principle also be achieved by means of a plurality of structural components 14 which may be arranged adjacent one another and parallel to one another or at an angle relative to one another. The device 9 may be constructed as a single piece or as a device consisting of a number of pieces and be made of, for example, a metal such as tungsten. When the limiting device 9 consists of two pieces, a detachable connection is possible between the parts 10 and 14, for example, in that the second beam cross-section limiter 14 can be retained in recesses 20 of the first beam cross-section limiter 10 by way of projections 19. A connection by way of screws, clamps or other positive locking connection elements is also feasible. It is also possible, for example, to insert the second beam cross-section limiter 14 first in an analysis device A, for example, in a holding groove, after which the first beam cross-section limiter can be arranged merely loosely thereon. Corresponding mounts in the analysis device A then ensure that the alignment of the parts 10 and 14 relative to one another is automatically correct. In order to enable the use for incoming as well as outgoing beams 5, 7, the first beam cross-section limiter 10 is provided with two passage apertures 12, 13 which intersect one another along an imaginary line of intersection 18. This line of intersection 18 is situated in the plane 15 in which the second beam cross-section limiter 14 is situated in the present embodiment. It comprises a passage aperture 16 for the rays, for example, X-rays (FIG. 4), which passage aperture starts from its edge zone 17 and is only partly enclosed. When the parts 10 and 14 are attached to one another, the passage apertures 12, 13 are intersected by the second beam cross-section limiter 14 along their line of intersection 18, so that the passage aperture 16 in the plane 15 extends perpendicularly to the passage apertures 12 and 13 and supplements these apertures each time so as to form a closed contour. This closed contour is shown in FIG. 5 for the incident beam 5 and in FIG. 6 for the exit beam 7 and forms each time substantially a circle in a projection perpendicular to the direction of propagation of the beams 5 and 7, respectively. However, it is also possible for the passage apertures 12, 13 as well as 16 to have a different contour geometry, for example, a square or rectangular contour. In that case, for example, for the incident beam 5 through the first passage aperture 12 of the first beam cross-section limiter 10 and the passage aperture 16 of the second beam cross-section limiter 14 there would be obtained a square or a rectangular entrance aperture, and also for the exit beam 7 formed by the second passage aperture 13 of the first beam cross-section limiter 10 and the passage aperture 16 of the second beam cross-section limiter 14. The limiting device 9 is mounted in the analysis device A in such a manner that it is positioned in front of a front surface of a sample 6 to be irradiated. The sample 6 is supported, for example by a sample holder 23 (FIG. 8). The second beam cross-section limiter 14 yields a double effect in respect of the removal of disturbing rays: on the one hand, rays 21 which are incident on the sample holder 23 or the edge zone of the second passage aperture 13 of the first beam cross-section limiter 10 and hence may give rise to undesirable secondary processes are eliminated, because they are stopped by the second beam cross-section limiter 14 and cannot traverse the comparatively small passage aperture 16 (denoted in FIG. 8 by wavy lines 21 in front of the second beam cross-section limiter 14 and by dashed wavy lines therebehind). On the other hand, rays 22 which are reflected on the edges of the first passage aperture 12 of the first beam cross-section limiter 10 or on the sample holder 23, or scattered or secondary rays caused by interaction processes, are stopped by the second beam cross-section limiter 10 (denoted in FIG. 8 by a wavy line in front of the second beam cross-section limiter 14 and by a dashed wavy line 22 behind said limiter). As is apparent from the dashed straight lines within the beams 5 and 7, the edges of the passage apertures 12, 13 and 16 also serve for edge limiting of the incident beam 5 and the exit beam 7. A typical dimension of the diameter of the light spot on the sample amounts to approximately 20 mm. Overall it is thus achieved that the incident beam is kept completely remote from the second passage aperture 13 in the first beam cross-section limiter 10, so that it cannot cause any secondary processes at the area thereof. The width of the incident beam 5 is limited on the one hand by the first passage aperture 12 in the first beam cross-section limiter 10 and on the other hand by the passage aperture 16 in the second beam cross-section limiter 14. It is also ensured that no reflected or secondary rays 22 from the first passage aperture 12 can invade the beam 7, because these rays are completely stopped. Therefore, the detector 8 receives only rays which in any case have not arisen in the edge zone of the first passage aperture 12. Secondary rays reflected by the sample holder 23 or the diaphragm material of the first beam cross-section limiter 10 or produced by interaction, therefore, are very effectively prevented from having an effect on the measuring result. |
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051924935 | description | DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 2 illustrates a simplified schematic representation of a typical pressurized water reactor-steam generator system in which the method and apparatus of the present invention to provide a median signal selector for feedwater control systems may be employed. Like reference numerals are employed among the various figures to designate like elements. The reactor vessel 50 has coolant flow inlet means 51 and coolant flow outlet means 52. The vessel 50 contains a nuclear core (not shown) consisting mainly of a plurality of clad nuclear fuel elements which generate substantial amounts of heat, depending primarily upon the position of control rods 53. The heat generated by the reactor core is conveyed from the core by coolant flow entering through inlet means 51 and exiting through outlet means 52. The flow exiting through outlet means 52 is conveyed through an outlet conduit 54 to a heat exchange steam generator system 55. The heated coolant is conveyed through heat exchange tubes 56 which are in a heat exchange relationship with water 57 which is used to produce steam. The steam produced by the steam generator 55 is utilized to drive a turbine 58 for the production of electricity as described more fully below. The flow of the coolant is then conveyed from the steam generator 55 through an inlet conduit 59 to inlet means 51. Thus, a closed recycling primary loop couples the reactor vessel 50 and the steam generator 55. The system shown in FIG. 2 is illustrated with one closed fluid flow loop although the number of loops and hence the number of steam generators 55 varies from plant to plant and commonly two, three, or four are employed. The secondary side of the steam generator 55 is isolated from the primary loop by the heat exchange tubes 56. The water 57 in the steam generator 55 is placed into a heat exchange relationship with the primary coolant, whereby the water 57 is heated and converted to a vapor or steam. The vapor flows through a steam conduit 60 to the turbine 58. The steam, after passing through the turbine 58, is condensed in a condenser 61. The condensate or water is returned to the secondary side of the steam generator 55 through conduit 62. Thus, a recycling, secondary loop couples the steam generator 55 to the turbine 58. Completing the description of the system shown in FIG. 2, three water level channels 10, 11 and 12 measure the level of the water 57 in the steam generator 55 and generate water level signals 13, 14 and 15, respectively, representative of the water level 57 in steam generator 55. A steam generator low water level reactor protection system and feedwater control system constructed according to the teachings of the present invention is shown in FIG. 3. The reactor protection system is constructed as follows. Water level signals 13, 14 and 15 generated by water level channels 10, 11 and 12, respectively, are input to water level comparators 16, 17 and 18, respectively. The water level signals 13, 14 and 15 are compared by water level comparators 16, 17 and 18, respectively, to a predefined steam generator water level set point. Low-low water level signals 19, 20 and 21 from water level comparators 16, 17 and 18, respectively, are input to coincidence gate 22. A low-low water level indication from any two of signals 19, 20 and 21 will cause a signal 23 to be generated which is available at an output of coincidence gate 22 to thereby initiate a reactor trip. A reactor trip is accomplished by inserting control rods 5 (shown in FIG. 2) into the nuclear core (not shown) to take the reactor to a subcritical state. Water level signals 13, 14 and 15 also serve as inputs to the feedwater control system. Water level signals 13, 14 and 15 are input to the feedwater control system through electrical isolation devices 70, 71 and 72, respectively. Electrically isolated water level signals 73, 74 and 75 from isolation devices 70, 71 and 72, respectively, serve as inputs to microprocessor 81 which is programmed to serve as the median signal selector 80. Signal 82, representative of the median water level signal, alarm signal 84 and feedwater control system operating mode signal 85 are output through known output interface 83 to the feedwater control system. The operation of the median signal selector 80 may be implemented as illustrated in the flow chart of FIG. 4. The flow chart begins at step 100 where the microprocessor 81 of FIG. 3, through known data acquisition techniques, samples the electrically isolated water level signals 73, 74 and 75. In step 101, electrically isolated water level signal 73 is stored in microprocessor 81 memory as Signal A; electrically isolated water level signal 74 is stored in microprocessor 81 memory as Signal B; electrically isolated water level signal 75 is stored in microprocessor 81 memory as Signal C. The microprocessor 81 then selects the high value between Signal A and Signal B in step 102 and stores the high value in microprocessor 81 memory as Signal D. Program control continues at step 103 where the high value between Signal B and Signal C is selected and stored in microprocessor 81 memory as Signal E. The microprocessor 81, in step 104, then selects the high value between Signal C and Signal A and stores the selected value in microprocessor 81 memory as Signal F. Program execution continues at step 105 where the low value between Signal D and Signal E is selected and stored in microprocessor 81 memory as Signal G. The microprocessor 81 determines the median signal as between Signal A, Signal B, and Signal C in step 106 where the low value between Signal G and Signal F is selected. The median signal 82 is then output by microprocessor 81 in step 107 to the feedwater control system through output interface 83. An example of the operation of the median signal selector 80 follows. Suppose that Signal A, Signal B and Signal C are signals representing 30%, 40% and 50% of maximum steam generator water level. After the high values are selected in steps 102, 103 and 104, Signal D, Signal E, and Signal F are each equal to 40%, 50% and 50% of maximum steam generator water level, respectively. Selection of the low value between Signal D and Signal E in step 105 yields a Signal G of 40% of maximum steam generator water level. Finally, the low value as between Signal G and Signal F, the median signal 82, is equal to 40% of maximum steam generator water level. Thus, the median signal selector 80 will always select the median of Signal A, Signal B and Signal C. A failure high or low of any water level channel 10, 11 or 12 (FIG. 3) will result in the corresponding water level signal 13, 14 or 15, respectively, being rejected by the median signal selector 80 thereby preventing the failure from causing a control system disturbance and initiating a transient which may require protective action. Several failure detection features may also be implemented in the median signal selector 80. These failure detection routines are functionally represented in step 108 of the flow chart of FIG. 4. If the value of any of the electrically isolated water level signals 73, 74 or 75 differs from the value of either of the remaining two signals by more than an allowable predetermined difference value, an alarm signal 84 is generated by microprocessor 81 and is output to the feedwater control system through output interface 83. Additionally, if the value of any of the electrically isolated water level signals 73, 74 or 75 is greater than a predetermined high limit signal value or is less than a predetermined low limit signal value, an alarm signal 84 is generated by microprocessor 81 and is output to the feedwater control system through output interface 83. In either case, the median signal 82 as calculated in step 106 is output to the feedwater control system through output interface 83 in step 107. The detection of a failure of any two electrically isolated water level signals 73, 74 or 75 (difference value, out-of-range) will cause the microprocessor 81 to generate a signal 85 output to the feedwater control system through output interface 83 to effect a transfer of the feedwater control system from automatic to manual. The last median signal 82 calculated by microprocessor 81 in step 106 of the flow chart of FIG. 4 prior to the failure detection will be output through output interface 83 to the feedwater control system in step 107. The median signal selector 80 eliminates the need to postulate the second random water level channel failure as required by standard IEEE-279 because the initiating water level channel failure does not result in a nuclear power plant condition requiring protective action. The median signal selector 80 prevents the failure of a single water level channel 10, 11 or 12 from initiating a feedwater control system transient. It is not necessary, therefore, to postulate the second random failure and, thus, two out of three water level channels 10, 11 and 12 remain in service. These two remaining water level channels are sufficient to satisfy the two out of three reactor trip logic implemented in the low-low water level reactor trip. The low feedwater flow reactor trip logic is, therefore, no longer required. The median signal selector 80 has eliminated the need for the low feedwater flow reactor trip thereby eliminating the need for the feedwater flow channels 27 and 28 and the steam flow channels 25 and 26 in the reactor protection system. While the present invention has been described in connection with an exemplary embodiment thereof, it will be understood that many modifications and variations will be readily apparent to those of ordinary skill in the art. This disclosure and the following claims are intended to cover all such modifications and variations. |
053496159 | abstract | The device (4) for the retention of core melt-through in light-water reactors by means of a crucible (40) disposed beneath the reactor pressure vessel (2) comprising of a vat (41) and a plurality of sack-like protuberances (42) on its underside and also of a metal lid (43). The lid forms a water-tight upper seal for the crucible and has a reinforcement (43b) to absorb the kinetic energy of the impact of the core melt-through. The crucible consists of a metal wall (40a), which is lined with a ceramic material (40b)--preferably made from high-temperature isostatic pressed boron nitride. The device (4) is disposed in a water-filled cooling basin (32), which forms the lowest part of the containment sump and which can be constructed as a cavity in the containment foundation. The water vaporized during cooling if the requirements are met condenses on the walls of the containment and flows back into the containment sump. |
claims | 1. An apparatus for delivering cooled fuel salt into a reactor core comprising:an exterior wall;an interior wall surrounding the reactor core and spaced apart from the exterior wall such that a plenum is formed between the exterior wall and the interior wall, the interior wall separating the reactor core from the plenum, the interior wall provided with a plurality of perforations penetrating the interior wall and permitting flow of nuclear fuel salt between the reactor core and the plenum;a top wall connecting the exterior wall and the interior wall; anda plenum inlet defined at least partially by the exterior wall and positioned opposite the top wall for receiving cooled nuclear fuel salt into the plenum, wherein the plenum has a tapered shape proximate the top wall, the plenum having a radial thickness that is greater at the plenum inlet than adjacent the top wall, and wherein the tapered shape of the plenum begins at a height above the plenum inlet. 2. The apparatus of claim 1, wherein the plurality of perforations are arranged into at least two horizontal rows of perforations. 3. The apparatus of claim 1, wherein at least one of the perforations in the plurality of perforations is a cylindrical hole through the interior wall having a central axis that is not parallel with a horizontal plane that is defined by the top wall. 4. The apparatus of claim 1, wherein at least one of the perforations in the plurality of perforations is a frustoconically shaped hole through the interior wall. 5. The apparatus of claim 1, wherein at least one of the perforations in the plurality of perforations is a frustoconically shaped hole through the interior wall having a central axis that is not parallel with a horizontal plane that is defined by the top wall. 6. The apparatus of claim 1, wherein the exterior wall tapers inwardly towards the interior wall proximate the top wall. 7. The apparatus of claim 1, wherein the plurality of perforations are spaced at different levels within the interior wall. 8. The apparatus of claim 7, wherein more perforations of the plurality of perforations are disposed proximate the plenum inlet than the top wall. 9. The apparatus of claim 1, wherein a base end of both of the exterior wall and the interior wall opposite of the top wall are positioned along a same horizontal plane that is parallel to the top wall. |
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052232115 | description | DESCRIPTION OF THE PREFERRED EMBODIMENT The above-mentioned deformation occurs because <0001> directions of a hexagonal Zr metal are oriented perpendicularly to zirconium alloy surfaces as shown in FIG. 2. When the hexagonal Zr metal is subjected to neutron irradiation, crystals contract in <0001> directions while expanding in directions perpendicular to <0001> directions. More strictly, an atomic plane (dislocation) perpendicular to (0001) plane is introduced by neutron irradiation to cause such contraction and expansion of crystals. Crystals are therefore irradiation-grown in longitudinal and widthwise directions in the case of a fuel channel box in which <0001> directions of crystals are oriented perpendicularly to its surfaces. The amount of neutron exposure is greater in a position closer to the center of the reactor core. Variations in the amount of neutron exposure cause variation in irradiation growth amount and, hence, bending deformation. Randomly orienting <0001> directions of crystals is effective in limiting the irradiation growth. The irradiation growth is a deformation without any change in volume. In the case of irradiation growth of crystal grains of a polycrystal, therefore, the polycrystal can be considered free of deformation as a whole, because, even if each of the crystal grains are deformed in a particular direction, all the directions of the deformation are random. For quantitative evaluation of crystal orientation, a method is ordinarily used in which an X-ray diffraction intensity of a particular crystal plane is measured based on a combination of reflected/ transmitted X-ray diffraction methods and F value is calculated by equation (1) from the X-ray diffraction intensity measured. ##EQU1## where .phi. is an angle between a particular direction (e.g., a direction perpendicular to the plate surface) and a particular crystal orientation (e.g., <0002> crystal orientation), and V(.phi.) is the volume proportion of crystals oriented in the direction .phi.. If directions r, t and l are respectively defined as a normal to the plate (tube) surface (Fr), the longitudinal direction of the plate (tube) (Ft), and the widthwise direction of the plate (the circumferential direction of the tube) (Fl) which directions are perpendicular to each other, then a relationship expressed by an equation (2): EQU Fr+Ft+Fl=1.0 (2) is established. If the crystal orientation is made completely random, EQU Fr=Ft=Fl=1/3 (3) The process is controlled so that each of Fr, Ft and Fl is 0.20 to 0.50. Preferably, Fr is 0.25 to 0.50, Ft is 0.25 to 0.36 and Fl is 0.25 to 0.36. Most preferably, each of Fr, Ft and Fl is 0.31 to 0.35. The Fr value of (0002) crystal planes (equivalent to (0001) planes) of a plate and a tube manufactured by a process based on repeating ordinary cold working and annealing is about 0.6, and <0001> directions of crystals are mainly oriented in the direction of a normal to the plate (tube) surface. This structure in which crystals are mainly oriented in the surface normal direction is called texture. FIG. 3 shows a relationship between neutron exposure and irradiation elongation with the Fr value used as a parameter. When the Fr value is not more than 0.50, preferably not more than 0.45, the irradiation elongation is remarkably reduced. If the Fr value is set to 0.333 to 0.35, the elongation is limited to substantially 0 (zero) even in a high irradiation range in which the amount of neutron exposure .gtoreq.10.sup.22 (n/cm.sup.2). A process comprising the steps of heating a zirconium alloy member to a .beta. phase temperature range (a temperature higher than 980.degree. C. in the case of a zircaloy), sufficiently growing .beta.Zr crystal grains and thereafter quenching the material by water spraying at the time of cooling may be used as a means for obtaining a texture in which the Fr value .ltoreq.0.50. By this process, hexagonal Zr crystals transform to cubic 8Zr crystals and again transform to hexagonal Zr crystals by cooling. To obtain by this heat treatment a texture in which the Fr value is 0.333 to 0.35, it is necessary to grow .beta.Zr crystal grains so that the grain size is at least 100 .mu.m. For a texture in which Fr value .ltoreq.0.50, .beta.Zr crystal grains need to be grown to have a size of at least 50 .mu.m, preferably at least 150 .mu.m. The period of time for heating in the .beta. phase temperature range may be shorter if the heating temperature in the .beta. phase temperature range is higher (preferably 1,000 to 1,350.degree. C., more preferably 1,000.degree. to 1,200.degree. C.). The period of time for retention at the maximum temperature may be very short. For example, it is 1.5 to 100 sec., preferably 5 to 60 sec. It is particularly preferable to effect heating in a range marked with in FIG. 8. In the case of retaining at an .alpha.+.beta. phase temperature, .alpha.Zr crystals remain, so that a preferable texture cannot be obtained. In another case of heating up to the .beta. phase temperature range, a preferable texture cannot be obtained if the retention time is short while the heating temperature is comparatively low. This is because in each of transformation from .alpha.Zr to .beta.Zr (during heating) and transformation from .beta.Zr to .alpha.Zr (during cooling), the transformation proceeds while such crystal orientation relationship that (0001) crystal planes of .alpha.Zr and (110) planes of .beta.Zr are parallel is maintained, so that no change in the crystal orientation occurs when heating and cooling are completed. To obtain a texture in which crystal orientation is random, it is necessary to grow .beta.Zr crystal grains having various crystal orientations. For this growth, a temperature or retention time is required high or long (0.8 or greater in terms of value P) enough to grow .beta.Zr crystal grains until the grain size is increased to at least 50 .mu.m. As described above, the Fr value varies according to the heat treatment, and the temperature and the retention time are important factors. Accordingly, to reduce the Fr value to 0.50 or less by heating in the .beta. phase temperature range, it is necessary to set the parameter P obtained by the equation shown above to 1.5 or greater (.beta.Zr crystal grain size of 60 .mu.m or greater). Preferably, the parameter P is 2.5 to 5 (a .beta.Zr crystal grain size of 70 to 500 .mu.m). More preferably, it is 3.2 to 5 (a .beta.Zr crystal grain size of 100 to 500 .mu.m). A suitable zirconium based alloy contains 5% or less by weight of Sn and/or 5% or less by weight of Nb and the balance 90% or more by weight (preferably, 95 to 98.5% by weight) of Zr. Sn and Nb are needed to increase the strength of Zr. 3% or less of Sn and 5% or less of Nb are required. Preferably, the lower limit of the content of each of Sn and Nb is 0.1%. A zircaloy contains, preferably, 1 to 2%, more preferably 1.2 to 1.7% of Sn. This alloy may contain 0.5% or less of Fe and 0.5% or less of Cr, this content of Cr and 0.2% or less of Ni, or these contents of Fe and Ni. Specifically, it may contain 0.1 to 0.38% Fe, 0.05 to 0.15% Cr and 0.03 to 1.25% Ni, or 0.22 to 0.38% Fe, 0.05 to 0.15% Cr and 0.09 to 0.15% Ni. In the latter case, Fe or Ni may be used singly. The Fe/Ni ratio is preferably 1.3 to 10. As examples of alloys containing Nb, there may be used Zr-0.5 to 2% Nb, Zr-2 to 5% Sn-0.5 to 1.5% Mo, Zr-0.5 to 0.15% Sn-0.5 to 1.5% Nb-0.1 to 1.0% Fe, Zr-0.5 to 5.0% Nb-0 to 3.0% Sn-2% or less of one or two or more of Fe, Ni, Cr, Ta, Pd, Mo and W. In a manufacture process in accordance with the present invention, a plate is successively heated for a desired retention time with an induction coil while being moved at the time of heating in the .beta. phase temperature range, and is forcibly cooled after the heating. By this heating to the .beta. phase, a structure can be obtained in which <0001> directions are randomly oriented and which has high corrosion resistance to high temperature and high pressure pure water. Preferably, cooling is performed by spraying water so that the cooling speed is not lower than 50.degree. C./sec., preferably, not lower than 150.degree. C./sec. Other heating means, such as infrared rays and an electric furnace, may be used. When heating in the .beta. phase temperature range, it is preferable to restrain the heated member by fixing it with a member having a thermal expansion coefficient larger than that of the Zr based alloy. In particular, in the case of a tubular member, it is preferable to perform heating and cooling in such manners that a metallic member is inserted into the inner cavity of the tube while reducing the thermal influence thereon by preventing contact between the whole surfaces of these members, and that opposite ends of these members are fixed to each other to prevent deformation of the tubular member during heating. If such a restraining member is provided, heating and cooling can be performed easily. As a material of this restraining member, an austenitic stainless steel, such as SUS304, 316 or 347, is preferred. Subsequently to the .beta. phase heat treatment, annealing for uniformly heating the whole member is performed. Annealing is effected at 500 to 650.degree. C. (preferably, 550.degree. to 640.degree. C.). For this heating as well, it is preferable to use the above restraining member to restrain the heated member, whereby the tubular member can be suitably shaped. This heat treatment is effect in a non-oxidizing atmosphere. It is particularly preferable to effect the treatment in Ar. By a final heat treatment, an oxide layer on the surface is removed by sand blasting and acid cleaning. After removing the oxide layer, the surface is oxidized by an autoclave to form a stable oxide layer thereon, thereby finishing the product. End portions which are fixed provided with screw holes and etc. for the above-mentioned fixing purpose are cut off and the material of these portions are reused. A channel box in accordance with the present invention is formed by abutting two generally U-shaped members on each other, plasma-welding the abutting portions to form a rectangular tube and making the welded portion flat, and is thereafter used. For the heat treatment of this rectangular tube, it is preferable to insert an X-shaped restraining member therein. The heat treatment according to the present invention may be applied to any one of the states of a plate state, a U-shaped state and a rectangular tube obtained after welding. Plate members heat-treated are used by being bent to be U-shaped (channel-shaped) and by being welded into a rectangular tube to be used. EMBODIMENT 1 Three zircaloys having alloy compositions shown in Table 1 were used. They were heat-treated under conditions shown in Table 2. TABLE 1 ______________________________________ Alloy Elements (wt %) Alloy Name Sn Nb Fe Cr Ni Mo O Zr ______________________________________ Zircaloy-4 1.50 -- 0.21 0.10 -- -- 0.12 bal. Zircaloy-2 1.50 -- 0.15 0.10 0.10 -- 0.12 bal. Zircaloy-C 1.50 -- 0.25 0.10 0.10 -- 0.12 bal. ______________________________________ TABLE 2 ______________________________________ Heat Maximum Retention time treat- heating at maximum Cooling ment temperature heating temp. rate No. (.degree.C.) (sec) (.degree.C./sec) P ______________________________________ 1 as-supplied state -- 2 900 (.alpha. + .beta.) 600 200 -- 3 1000 (.beta.) 60 200 2.31 4 1000 (.beta.) 600 200 3.61 5 1200 (.beta.) 60 150 4.16 6 1000 (.beta.) 5 200 0.91 ______________________________________ Each of the alloys was provided as a plate having been formed to have a thickness of 2 mm by the repetition of cold rolling and annealing at 650.degree. C. for two hours before being used in heat treatment tests shown above. Heat treatments 2 to 4 shown in Table 2 were effected in such a manner that test pieces having a width of 400 mm and a length of 40 mm were cut from the materials, heated in an electric furnace and cooled in water. The parameter P was calculated by the above-mentioned equations. Table 3 shows the results of F value measurement with respect to (0002) plane (parallel to (0001) plane) and (1010) plane (vertical to (0001) plane) of heat-treated members 1 to 6. The F value measurement was performed by a method based on the combination of reflected/transmitted X- ray diffraction methods mentioned above. In the case of a tubular member, Fr is a rate of orientation in a direction perpendicular to the surface thereof, Ft is a rate of orientation in the longitudinal direction thereof, and Fl is a rate of orientation in the circumferential direction thereof. TABLE 3 ______________________________________ Heat (0002) Plane (1010) Plane treatment No. Fr Fl Ft Fr Fl Ft ______________________________________ 1 0.672 0.108 0.220 0.158 0.448 0.393 2 0.666 0.124 0.210 0.156 0.445 0.398 3 0.414 0.295 0.292 0.301 0.354 0.345 4 0.335 0.352 0.318 0.325 0.329 0.344 5 0.336 0.334 0.330 0.330 0.335 0.335 6 0.470 0.203 0.327 0.209 0.401 0.390 ______________________________________ In the case of the plate (heat treatment No. 1) manufactured by repeating both cold rolling and annealing, the Fr value of (0002) planes is large, about 0.7 while the Fr value of (1010) planes is small (about 0.15) in comparison with Fl and Ft. From these results shown in Table 3, it can be understood that (0002) planes are oriented generally parallel to the plate surface. The F value of the member (heat treatment No. 2) heated to the .alpha.+.beta. phase temperature range and cooled is generally equal to that of the as-supplied member (heat treatment 1). It is thereby understood that the texture is not changed by heating to and cooling from the .alpha.+.beta. phase temperature range. In the cases of heating in the .beta. phase temperature range (1,000.degree. C.) for 1 minute and 5 seconds followed by cooling (heat treatment Nos. 3 and 6), a reduction in the Fr value and increases in the Fl and Ft values of (0002) planes, and an increase in the Fr value and reductions in the Fl and Ft values of (1010) planes are recognized in comparison with the as-supplied member, and the crystal orientation is made random. However, it does not satisfy Fr value .ltoreq.0.35, which is a target value enabling use in such high irradiation range as the amount of neutron exposure .gtoreq.10.sup.22 (n/cm.sup.2). In the cases of retention at 1,000.degree. C. for 10 minutes (heat treatment No. 4) and increasing the heating temperature to 1,200.degree. C. (heat treatment No. 5 ), each of the F values of (0002) planes and (1010) planes is about 0.33, and it is understood that the crystal orientation is made substantially completely random. As described above, neither bending deformation nor elongation deformation is caused in the members processed by heat treatments 4 and 5, even if the internal neutron exposure is non-uniform. FIG. 3 is a diagram showing a relationship between high-speed neutron exposure and irradiation growth strain. As shown in FIG. 3, the strain is abruptly increased as the amount of neutron exposure is increased, if the Fr value is greater than 0.4, but the strain is saturated and is not increased under irradiation, if the Fr value is not greater than 0.4. Specifically, in the case of Fr=0.35, <0001> crystal orientation is substantially random, so that strains in the direction of the normal, the longitudinal direction and the direction of the plate thickness are cancelled out between crystals, that is, the strain is substantially naught, not greater than 0.5.times.10.sup.-4. In the case of Fr=0.4, the strain is small when the amount of neutron exposure is not greater than 3.times.10.sup.22 n/cm.sup.2, but is gradually increased as the amount of neutron exposure is increased from this level. In contrast, when Fr=0.35, the strain is not increased even if the amount of neutron exposure is increased. FIG. 4 is a diagram showing the relationship between the Fr value and the irradiation growth strain caused by high-speed neutron irradiation at 3.times.10.sup.22 n/cm.sup.2. With the increase in the Fr value, the amount of strain is increased abruptly. The strain caused by irradiation growth when Fr=0.35 is about 0.2.times.10.sup.-4. This value is particularly small, that is, about 1/7 of the strain occurring when Fr=0.4, which causes strain of about 1.5.times.10.sup.-4. The strain caused in the Fr=0.4 case is much smaller than the strain occurring when Fr =0.5, that is, 1/3 of the same. However, the strain occurring when Fr=0.6 is about a half of that when Fr =0.7. The strain limiting effect becomes comparatively small when Fr exceeds 0.4. Roundish crystal grains observed in the metallic structure of each of the heat-treated member Nos. 1, 3, and 4 are .beta.Zr grains. No .beta.Zr crystal grains were observed. Polygonal crystal grains are .beta.Zr crystal grains formed during heating in the .beta. phase temperature range. It is understood that as the 1,000.degree. C. retention time is increased from 1 to 10 minutes, .beta.Zr crystal grains grow largely. A layered or acicular structure observed in .beta.Zr crystal grains is formed when .beta.Zr transforms into .alpha.Zr again during cooling, and is not a .beta.Zr grain boundary. FIG. 5 shows the relationship between the .beta.Zr crystal grain size and the Fr value of (0002) planes. It is understood that a texture having an Fr value 0.35 or smaller is formed by such growth of .beta.Zr crystal grains as having a grain size of 200 .mu.m or greater. It is possible to make the crystal orientation of (0002) planes random by the growing of crystal grains. The degree of randomness of this orientation is about 75% when value is 0.40. The grain size at this time is about 100 .mu.m. When the grain size exceeds 150 .mu.m, the degree of randomness is about 80% or higher. At this time the Fr value is 0.385. When the Fr value is 0.35, the degree of randomness is about 90% or higher. At this time the grain size is about 250 .mu.m or greater. FIG. 6 is a diagram showing the relationship between the .beta.Zr crystal grain size and the irradiation growth strain. The strain occurring when the grain size is 90 .mu.m or greater is remarkably small, about 1.5.times.10.sup.-4. The strain becomes very small, 0.5.times.10.sup.-4 or less when the grain size is 150 .mu.m or greater. It is particularly small, about 0.3.times.10.sup.-4 when the grain size is 200 .mu.m or greater. FIG. 7 is a diagram showing the relationship between the parameter P=(3.55+logt).times.log(T-980) and the irradiation growth strain. As shown in FIG. 7, the strain of irradiation growth is greatly influenced by the parameter P determined in accordance with the relationship between the temperature and the retention time of the heat treatment. The parameter P is an important factor of determination of the Zr<0001> crystal orientation rate. In the case of the heat treatment at 1,000.degree. C., the strain of irradiation growth is abruptly reduced when P exceeds 0.5, is gradually further reduced as P is changed from 0.5 to 3.5, and is approximately constant and close to zero when P is 3.5 or greater. When P is smaller than 3.5, irradiation growth occurs. When P is 3.5 or greater, substantially no irradiation growth occurs. The effect of limiting the irradiation growth strain is sufficiently high when P is 1.5 or greater. Preferably, P is set to 3.2 to 5. FIG. 8 is a diagram of the Fr values of alloys shown in Tables 1 and 4 with respect to the temperature and the retention time. As shown in FIG. 8, when the temperature is lower than 980.degree. C., the Fr value is 0.20 or smaller and it is difficult to make <0002> crystal orientation random. However, by heating at 980.degree. C. (1,000.degree. C.) or higher for 11 sec. (10.5 sec.) or longer or at 1,240.degree. C. or higher for 1.1 sec. or longer, i.e., heating under conditions as defined on or above a line connecting the points indicating these temperatures and times, the heat-treated member can have an Fr value exceeding 0.25 and a higher degree of randomness. By heating at 980.degree. C. or higher for 6 sec. or longer or at 1,240.degree. C. or higher for 6 sec. or longer, i.e., heating under conditions as defined on or above a line connecting them, the heat-treated member can have an Fr value greater than 0.20 and equal to or smaller than 0.25. In the case of heating under conditions defined below this line, the Fr value is equal to or smaller than 0.20, the degree of randomness is small, and the effect of limiting the elongation is small. TABLE 4 ______________________________________ Alloy Elements (wt %) Fe/Ni Alloy Name Sn Fe Cr Ni O Zr ratio ______________________________________ Zircaloy-2 1.50 0.15 0.10 0.05 0.11 bal. 3.0 Zircaloy-A 1.50 0.23 0.10 0.05 0.11 bal. 4.6 Zircaloy-B 1.50 0.23 0.10 0.09 0.11 bal. 2.6 Zircaloy-C 1.50 0.13 0.10 0.09 0.11 bal. 1.4 Zircaloy-D 1.50 1.10 -- 0.08 0.11 bal. 1.3 ______________________________________ EMBODIMENT 2 FIG. 9 shows an example of manufacture of a channel box in accordance with the present invention. Two members formed of Zircaloy C described with respect to Embodiment 1 were worked by cold bending into two channel-shaped members each having a length of 4 mm. These channel-shaped members were plasma-welded into the shape of a rectangular tube 1. Welded portions were finished flat so as to remove irregularities. A mandrel 2 formed of SUS304 (JIS) stainless steel was inserted in the rectangular tube 1 and was fixed to the same with screws 3. The rectangular tube 1 was thereafter heated to the .beta. phase temperature range by high-frequency induction heating using a high-frequency induction heating coil 4 and a high-frequency power source 5 and was quenched by cooling water strayed through nozzles 6 disposed immediately below the high-frequency induction heating coil 4. Hot water may be used as this cooling water. The mandrel 2 were formed so as to reduce the area of contact with the heated member in order to minimize the thermal influence upon the heated member. The rectangular tube 1 was passed through the coil at a constant speed vertically upwardly to be entirely heat-processed. The rectangular tube 1 feed speed and the output of the high-frequency power source 5 were controlled to set heating temperatures of 1,300.degree. C. and 1,200.degree. C. with a retention time of 20 sec. and a heating temperature of 1,100.degree. C. with a retention time of 10 sec. After the heat treatment, test pieces having a width of 40 mm and a length of 40 mm were cut out and the F values thereof were measured by the X-ray diffraction method. Table 5 shows the results of this measurement. The parameter P is 3.26 in the case of heating at 1,300.degree. C., 3.05 in the case of 1,200.degree. C., or 2.07 in the case of 1,100.degree. C. TABLE 5 ______________________________________ (0002) plane (1010) plane Fr Fl Ft Fr Fl Ft ______________________________________ 0.333 0.333 0.334 0.333 0.334 0.333 ______________________________________ As can be understood from Table 5, each of the F value of (0002) and (1010) planes was reduced to 1/3 and the crystal orientation was made completely random. These samples were tested by high-speed neutron irradiation. The strain caused by irradiation at 3.times.10.sup.22 n/cm.sup.2 was very small, about 0.3.times.10.sup.-4 or less. The crystal grain sizes of these samples were 100, 150 and 250 .mu.m, respectively. After this heat treatment, there were effected sand blasting and acid cleaning to remove an oxidized layer of the tubular member from the surface thereof and thereafter an autoclave treatment using water vapor was effected. FIG. 10 is a cross-sectional view of a part of a BWR fuel assembly using a tubular member manufactured in the above-described manner. The BWR fuel assembly is constituted of, as illustrated, a multiplicity of fuel rods 11, spacers 12 for maintaining a predetermined spacing between the fuel rods 11, a tubular channel box 1 in which the rods 11 and the spacers 12 are accommodated, upper and lower tie plates 14 and 15 for supporting both ends of the fuel rods containing fuel pellets, and a handle 13 for carrying the whole assembly. This fuel assembly is manufactured by a complicated manufacture process and the components are assembled by welding. The fuel channel box 1 is used while containing the fuel rods 11 set with the fuel spacers and while having the fuel rods fixed by the upper and lower tie plates 14 and 15. The fuel channel box has the shape of a rectangular tube formed by plasma-welding two channel-shaped members as described above. This member serves to forcibly lead high-temperature water and water vapor generated at the fuel rods to an upper section during plant operation. It is used for a long period of time while always receiving such stress that the rectangular tube tends to expand outwardly. The fuel assembly channel box is exposed to high-temperature high-pressure core water and subjected to neutron irradiation during use. Also, it receives an internal pressure because the pressure in the rectangular tube is higher than the external pressure. It is thereby necessary for the fuel assembly channel box to have corrosion resistance in a high-temperature and high-pressure environment and high creep deformation resistance under neutron irradiation. Zirconium based alloys ordinarily have high corrosion resistance and a small neutron absorption sectional area. Because of these characteristics, they are suitable for a reactor fuel assembly material and are used to form fuel cladding tubes, channel box 1 and spacers 12 constituting the fuel assembly. Examples of available zirconium based alloys are Zircaloy-2 (1.2 to 1.7 wt % Sn, 0.07 to 0.2 wt % Fe, 0.05 to 0.15 wt % Cr, 0.03 to 0.08 wt % Ni and the balance Zr), Zircaloy-4 (1.2 to 1.7 wt % Sn, 0.18 to 0.24 wt % Fe, 0.05 to 0.15 wt % Cr and the balance Zr), Zr-0.5 to 2 wt % Nb alloy, Zr-2 to 5 wt % Sn-0.5 to 1.5 wt % Nb-0.5 to 1.5 wt % Mo alloy, Zr-0.5 to 1.5 wt % Sn-0.5 to 1.5 wt % Nb-0.1 to 1.0 wt % Fe alloy, and Zr-Nb (0.5 to 5.0 wt %)-Sn (0 to 3 wt %)-one or two or more of Fe, Ni, Cr, Ta, Pd, Mo and W (2 wt % or less) alloy. It has been confirmed that the present invention is effective when applied to any of plates made of these alloys. These zircaloys are used for the cladding tube channel box and spacers in a boiling water reactor. However, local oxidation (nodular corrosion) is apt to occur, in particular, in cladding tubes. It is therefore preferable to effect hardening of only the outer surface thereof from the .alpha.+.beta. phase or .beta. phase before final cold working but after final hot working. Preferably, the temperature of heating for hardening is 825 to 1,100.degree. C., and the retention time at the temperature is within 1 minute, more preferably 3 to 30 seconds. Preferably, heating is effected in continuous manner by use of an induction coil and cooling is effected by spraying water subsequently to the heating. Heating may be performed while causing water to flow in the tube. Preferably, for cladding tubes, the Fr value of <0001> orientation perpendicular to the tube surface is set to 0.66 or greater. For the hardening of the cladding tube, the temperature and the time are controlled so as to prevent the crystal orientation from being made random. Zirconium-niobium alloy containing Nb has a large strength, improved creep characteristics, a low hydrogen absorption rate and is free from local corrosion called nodular corrosion. These characteristics are suitable for a fuel assembly member material. However, they are disadvantageous in that corrosion of welded portions and thermally influenced portions is accelerated so that a separable, thick white oxide is easily formed. A zirconium alloy containing 0.5 to 2.0 wt % Nb, 1.5 wt % or less of Sn and 0.25 wt % or less of a third alloy element selected from the group consisting of Fe, Cr, Mo, V, Cu, Ni and W, formed as a niobium-zirconium multi-element alloy, has a special microstructure having corrosion resistance in a high-temperature vapor environment. The channel box in accordance with the present invention, formed of these alloys, is obtained by heating for a suitable time and by quenching so that each of the F values of (0002) and 1010) planes is reduced to 1/3. The channel box thereby formed can be used at a degree of burn- up of 45 Gwd/t as well as at 32 Gwd/t, and can also used in a 2-cycle manner such that a clad attached to the surface is removed and the fuel is changed to reuse the box. Because the amount of deformation is minimized, it can be used in the same position in the core as the previous use. It is also preferable to effect the same heat treatment and orientation provision for cladding tubes formed of the above-mentioned alloys other than the zircaloy as those effected in the zircaloys. According to the present invention, as described above, the crystal orientation of a fuel assembly zirconium member can be made random, so that no serious bending deformation due to irradiation growth occurs even during use in a high irradiation environment in which the amount of neutron irradiation exceeds 10.sup.22 (n/cm.sup.2). The fuel assembly zirconium member can therefore be used for a long time, which effect contributes to the reduction in the spent fuel waste. The fuel assembly zirconium member is also improved in corrosion resistance and, hence, in reliability. |
041692292 | abstract | In an illustrative embodiment an electron beam is keyed into an operative scanning path through a small aperture by applying keying signals of opposite polarity to respective symmetrically arranged meander conductors. The keying signals produce respective traveling waves which periodically come into proximity to the beam electrons (in synchronism with beam velocity) at successive points along the beam path. The opposite potentials of the meander conductors except during keying operations produce transverse fields at the interaction points which progressively deflect the beam out of its operative path. During key-in, the effective deflection field on a beam electron packet is abruptly decreased in magnitude at each successive interaction point while the symmetrical arrangement of the meander conductors along the beam axis avoids the production of a longitudinal field component which would provide an adverse defocussing effect on the beam electrons. |
description | This application is a continuation of application Ser. No. 11/742,589, filed on Apr. 30, 2007, now U.S. Pat. No. 7,647,935, which claims the benefit of provisional Application No. 60/746,095, filed on May 1, 2006, which are hereby incorporated by reference in their entireties. FIG. 1 shows an example of a block diagram for creating a radionuclide containment composition. FIG. 2 shows an example of a flow diagram for containing radioactive materials. FIG. 3 shows an example of a block diagram of a radioactive material sequestration system. FIG. 4 shows an example of sequestering radioactive materials with the sorption based media. FIG. 5 shows the structure of a 2:1 clay mineral. FIG. 6 shows an example of a TEM image of lamellar aggregate of montmorillonite and an associated SAED diffraction pattern. FIG. 7 shows another example of a TEM image of a particle exhibiting some straight edges and an associated SAED diffraction. FIG. 8 shows an example of a TEM image of a subhedral platy particle of montmorillonite showing some near straight edge terminations and an associated SAED diffraction pattern. FIG. 9 shows an example of a TEM image of lamellar aggregate of montmorillonite used in fluid and an associated SAED diffraction pattern. FIG. 10 shows another example of a TEM image of lamellar aggregate of montmorillonite used in fluid and an associated SAED diffraction pattern. FIG. 11 also shows another example of a TEM image of lamellar aggregate of montmorillonite used in fluid and an associated SAED diffraction pattern. FIG. 12 shows yet another example of a TEM image of lamellar aggregate of montmorillonite used in fluid and an associated SAED diffraction pattern. FIG. 13 shows an example of a TEM image from grain mount showing morphology of montmorillonite particles. FIG. 14 shows another example of a TEM image from grain mount showing morphology of montmorillonite particles. FIG. 15 also shows another example of a TEM image from grain mount showing morphology of montmorillonite particles. FIG. 16 shows yet another example of a TEM image from grain mount showing morphology of montmorillonite particles. FIG. 17 shows an EDS compositions plot for Al2O3 and SiO2 in wt % of montmorillonite used. FIG. 18 shows an EDS compositions plot for Al2O3 and Fe2O3 in wt % of montmorillonite used. FIG. 19 shows an EDS compositions plot for MgO and Fe2O3 in wt % of montmorillonite used. FIG. 20 shows examples of TEM images and respective SAED diffraction patterns of Cs-reacted montmorillonite particles. FIG. 21 shows examples of TEM images and respective SAED diffraction patterns of Sr-reacted montmorillonite particles. FIG. 22 shows a powder X-ray diffraction patterns for palygorskite-rich media. FIG. 23 shows an EDS compositions plot for Al2O3 and SiO2. FIG. 24 shows an EDS compositions plot for Fe2O3 and Al2O3. FIG. 25 shows an EDS compositions plot for MgO and Fe2O3. FIG. 26 shows an EDS compositions plot for MgO and Al2O3. FIG. 27 shows an SEM image of palygorskite rich clay used as the sorption based media. FIG. 28 shows another an SEM image of palygorskite rich clay as the sorption based media. FIG. 29 shows an additional SEM image of palygorskite rich clay as the sorption based media. FIG. 30 shows an SEM image of the upper edge termination of the central platy particle. FIG. 31 shows a TEM image of a strontium chloride reacted sample showing interlocking palygorskite fibers. FIG. 32 shows TEM images of Cs-exchange with the sorption based media. FIG. 33 shows TEM images of a mixture of the sorption based media and radioactive containment composition. FIG. 34 shows additional TEM images of a mixture of the sorption based media and radioactive containment composition. The present invention embodies compositions, methods and systems for removing sequestered radioactive materials that have been contained by a radionuclide containment composition. As an embodiment, radioactive material sequestration system may comprise a radionuclide containment composition dispenser and a sorption based media container. The radionuclide containment composition dispenser, which may hold a radionuclide containment composition, may dispense the radionuclide containment composition to remove radionuclides from a radioactive material. When the radionuclide containment composition comes in contact with the radioactive material, the contact generally allows the radionuclides to be exchanged with cations in the radionuclide containment composition. As a result, an aqueous slurry may be formed. The radionuclides can be collected from the aqueous slurry by using a sorption based media, which may be stored in the sorption based media container. Besides serving as a container for holding the sorption based media, the sorption based media container can also be configured for receiving the dispensed radionuclide containment composition and sequestering the radionuclides. As another embodiment, the radionuclide containment composition may comprise a mixture of a clay mineral and water, forming an aqueous clay suspension. The mixture may be refined into a uniform suspension by filtering the mixture to remove coarse material. As another embodiment, the clay mineral is montmorillonite. As another embodiment, the weight ratio of the clay mineral to the water ranges from 1:99 to 99:1. As another embodiment, the mixture of the clay mineral and water is refined by using sieves to filter and remove coarse material. The aperture size of the sieves can range from 300 μm to <38 μm. Typically, a minimum size of 5 microns was found to be the functional limit to produce materials efficiently. As another embodiment, the sorption based media is a clay mineral from the palygorskite-sepiolite mineral group. As another embodiment, the sorption based media may sequester radioactive materials by chemical ion exchange, mechanical separation of floccules, or both. As another embodiment, to move the aqueous slurry towards the sorption based media, a probe may be used. As another embodiment, the probe is an ultrasonic probe. As another embodiment, the probe may have an illuminator device. Examples include flashlights, fluorescent lights, night vision apparatuses, electroluminescent devices, light emitting diodes, etc. As another embodiment, the probe may have a camera. As another embodiment, the probe may have a video camera. As another embodiment, the probe may have a digital camera. As another embodiment, the probe may have a radiation detector. As another embodiment, the probe may have a chemical sensor. As another embodiment, the probe may have a sensor for biological materials. As another embodiment, the probe may have a sensor for bioweapons, including but not limited to, anthrax, smallpox, and similar agents. As another embodiment, the probe may have a sensor for chemical weapons, including but not limited to, VX, sarin, ricin, chlorine, hydrofluoric acid and similar materials. Radioactive isotopes (also referred to herein as radionuclides) are naturally occurring in the environment or are created using nuclear technologies, such as nuclear reactors, etc. Human exposure to many types of radioactive isotopes may lead to several detrimental health effects, such as cancer, skin burn, organ malfunction, etc. Examples of radioactive isotopes, which are of concern to human health, include, but are not limited to, americium-241 (241Am), cesium (134Cs, 137Cs), cobalt-60 (60Co), iodine-131 (131I), iridium-192 (192Ir), plutonium (238Pu, 239Pu, 240Pu, and 242Pu), strontium-90 (90Sr), uranium-235 (235U), uranium-238 (238U) and chlorine-36 (36Cl). Radiological materials can be weaponized in many forms by terrorists and used for terrorist attacks. For instance, materials can be packed in a traditional explosive device and detonated in a public area. Such deployment is commonly referred to as a radiological dirty bomb or a radiological dispersal device (RDD). Because of the possibility of RDD use, a major concern of security deals with water sources, such as public water supplies, rivers, lakes, streams, aquifers, water wells, water storage tanks, water treatment plants, bottling facilities (e.g., water, soda, beer, etc.), sewers and other drainage systems, water pipes, marsh lands, swimming pools, etc. Water is an absolute necessity. If radioactive and/or hazardous materials were used as chemical weapons or dirty bombs and such materials somehow entered into any water supply, catastrophic results can easily occur. Similar health effects can also occur in nonwater environments or areas where some amount water can be found. For example, dirty bombs or chemical weapons with radioactive material used in parks, buildings, streets, cars, etc. can also have similar deleterious and/or carcinogenic health effects. One radioactive material of current interest that may be used in RDD is radioactive chloride. While two stable isotopes of chlorine, 35Cl and 37Cl, occur naturally, several radioactive isotopes of chlorine also exist, as indicated in TABLE 1. TABLE 1Radioactive Isotopes of ChlorineNuclearModeNuclearmagneticIsotopeMassHalf-lifeof decayspinmoment36Cl35.9683301,000yearsβ− to 36Ar01.2854738Cl37.96837.2minutesβ− to 38Ar22.0539Cl38.96855.6minutesβ− to 39Ar3\240Cl39.97041.38minutesβ− to 40Ar241Cl40.970734secondsβ− to 41Ar42Cl41.97326.8secondsβ− to 42Ar43Cl42.97423.3secondsβ− to 43Ar Of particular concern is 36Cl, which, as shown in TABLE 1, has a half-life of approximately 301,000 years. Its specific activity is about 0.033 (Ci/g) and decays via beta particle emission (generally 98% of decay occurs through this mechanism) and electron capture. The radiation energy is about 0.027 MeV. Lifetime cancer mortality risk coefficient for inhalation is about 9.6×10−11 pCi. Lifetime cancer mortality risk coefficient for ingestion is about 2.9×10−12 pCi. The 36Cl isotope is typically found naturally in very minute quantities from cosmogenic radiation interactions with 36Ar in the atmosphere, and may be used as a geochronological tool. Additionally, this isotope may also be found in the nuclear water stream. Hence, this isotope can be a component in RDD. It may also become an environmental concern if released into the environment. Previously, 36Cl has been produced in large quantities during nuclear weapons testing between 1952 and 1958. The mode of production was achieved by irradiation of seawater. For instance, at the U.S. Department of Energy, Hanford site, graphite neutron moderation material in plutonium production reactors was treated with Cl2 gas at high temperatures. The 35Cl that remained in the reactors was converted to 36Cl. Currently, 36Cl may be found in these reactors, as well as similar reactors, and waste streams from them. The amount of 36Cl that has been generated by the former Soviet Union and other countries with nuclear capabilities or developing capabilities remain unclear. Another radioactive material that may be used in RDD is cesium-137 (137Cs). Cesium-137 commonly occurs as 137CsCl and as a major component of nuclear waste stream generated from nuclear technologies worldwide. 137Cs decays by emission of beta particles and gamma rays to barium-137m (137Ba), a short-lived decay product, which in turn decays to a non-radioactive form of barium (134Ba). 137Cs has a half-life of approximately 30 years. As one of the most common radioactive isotopes used in various industries, 137Cs can be implemented in numerous devices. Examples include, but are not limited to, moisture-density gauges in the construction industry, leveling gauges in the piping industry, thickness gauges in industries (such as metal, paper and film), and well-logging devices in the drilling industry. Another fairly common radioactive isotope is 134Cs. Having similar properties to 137CS, 134Cs decays (e.g., beta decay) to 134Ba. The half life of 134CS is approximately 2 years. 134Cs may be used in photoelectric cells in ion propulsion systems under development. However, when comparing 137Cs with 134CS, 137Cs tends to have more significant environment and health concerns than 134Cs. For instance, 137CS is often a greater environmental contaminant than 134Cs. Moreover, although 137CS is sometimes used in medical therapies to treat cancer, exposure to 137Cs (like other radionuclides) can also increase the risk of cancer and damage tissue because of its strong gamma ray source. Nonetheless, 134Cs can still be a concern for the environment. Because of cesium's chemical nature, cesium can easily move through the environment, and thus making the cleanup of 137Cs releases difficult. For example in April 1986, large amounts of 137Cs were released during the Chernobyl incident. Significant amounts of 137Cs were deposited in Europe and Asia. Today, 137Cs can still be found in those areas. According to Great Britain's National Radiological Protection Board, there may be up to 1,000 additional cancers over the next 70 years among the population of Western Europe exposed to fallout from the nuclear accident at Chernobyl, in part due to 137Cs. Yet, of course, the magnitude of the health risk depends on exposure conditions. These conditions include factors such as strength of the source, length of exposure, distance from the source, and whether there was shielding between the person and the source (such as metal plating). Although several routes may exist in delivering 137Cs as a weapon, one expected route is dispersing 137Cs in the form of radioactive cesium chloride powder (137CsCl) in populated areas (e.g., downtowns, malls, etc.). Another anticipated route of dispersing 137Cs is through water supplies. For example, if 5 kg of 137CsCl were deposited and dispersed (whether via a dirty bomb or other means) in a large city (e.g., Chicago) having 5 m.p.h. winds, a computer model generated by the Los Alamos National Labs predicts that approximately 300 city blocks would be affected one hour after detonation. Risk of cancer may increase from 1 to 10-fold. The high solubility in water and the relatively low hardness of 137CsCl are both properties that are normally characteristic of an effective “radiological powder weapon.” In addition to 137Cs, it is well within the scope of the present invention that other radioactive isotopes may be used as the radioactive ingredient in a radioactive material for use in a dirty bomb or some form of weapon. Examples include all of the radioactive isotopes previously mentioned. To contain dispersed radioactive material as a weapon (e.g., RDD) having a radioactive isotope or radionuclide, a radionuclide containment composition may be used. The radionuclide containment composition is defined as an aqueous clay suspension comprising a mixture of a clay mineral and water. This suspension may be filtered to remove residual coarse material to impart a processed uniform suspension. Referring to FIGS. 1 and 2, the overall radioactive material sequestration may begin by mixing a clay mineral 105 with water 110 to form an aqueous clay suspension 115, S205. The aqueous clay suspension 115 can be refined by filtering 120 to remove residual coarse material S210. Filtering may be achieved by using sieves with aperture sizes ranging from 300 μm to <38 μm. The resulting refined aqueous clay suspension may be referred to hereinafter as radionuclide containment composition 125. The radionuclide containment composition 125 may be applied to a radioactive material S215. The application may form an aqueous slurry. Radioactive nuclides trapped within this aqueous slurry may be removed using a sorption based media S220. A probe may be used to assist the aqueous slurry to come into contact with the sorption based media. As shown in FIG. 3, the present invention also embodies a radioactive material sequestration system 305. The radioactive material sequestration system 305 may comprise a radioactive containment composition dispenser 310 and a sorption based media container 315. The radioactive containment composition dispenser 310 may be configured for holding a radionuclide containment composition 125 and being capable of dispensing said radionuclide containment composition 125 to remove radionuclides from one or more radioactive materials. The sorption based media container 315 may be configured for holding a sorption based media; receiving dispensed radionuclide containment composition 125; and sequestering radionuclides. The radioactive material sequestration system 305 can be operated manually or automatically. Manual operation may include turning on/off a release mechanism (e.g., a switch or valve, etc.). Automatic operation may include the use of sensors that automatically dispenses the radioactive containment composition 125 from the radioactive containment composition dispenser 310 when the sensors detect the presence of radionuclides, chemicals, biohazardous materials, etc. or when a certain threshold of radioactivity is met. The radioactive material sequestration system 305 may also incorporate a wireless mechanism (e.g., card or other device) that allows the system to be operated remotely and/or wirelessly. A computer or a device may execute a computer-readable program to instruct the radioactive containment composition dispenser 310 to dispense the radionuclide containment composition 125. It may also instruct the timing, amount and rate of dispensing. It may also indicate the levels of radionuclide containment composition 125 remaining in the radioactive containment composition dispenser 310. FIG. 4 illustrates an example of how the sorption based media can sequester radioactive materials. As exemplified in A, a pipe 405 may contain water and scale. In B, the pipe 410 may be contaminated with radioactive materials 415. In C, the radionuclide containment composition 125 having a montmorillonite-based liquid is injected into the pipe 420. The combination of the radionuclide containment composition 125 and radioactive materials 415 may create an aqueous slurry 425. It is possible that the radionuclide containment composition 125 may be poured into the pipe 420. Alternatively, it 125 may or be dispersed into the pipe 420 from a radionuclide containment composition dispenser 310. In D, after such composition 125 is sent, a probe 435, such as an ultrasonic probe, may be inserted into the pipe 430. The probe 435 is activated to encapsulate and remove radioactive materials and/or scale 440. This radioactive waste mixture 440 may pass through sorption based media 445, which may for instance comprise palygorskite-rich media, to collect floccules and fine polish the water. Using a probe may provide a multitude of advantages. For instance, the probe can help move the aqueous slurry towards the sorption based media. The probe may be an ultrasonic probe that sends sonic pulses to move the aqueous slurry. It may also be a rod, pipe cleaner, flexible brush, etc. To help one see where the radioactive materials and/or aqueous slurry may be present, the probe may have an illuminator device, camera, video camera, digital camera, etc. Examples of the illuminator device include flashlights, fluorescent lights, night vision apparatuses, electroluminescent devices, light emitting diodes, etc. The probe may even include a detector or sensor to detect radioactive, chemical and/or biological materials. Nonlimiting examples of detectors include a radiation detector, a chemical sensor, a sensor for biological materials, a sensor for bioweapons, including but not limited to, anthrax, smallpox, and similar agents, etc. The present invention can be used to clean or remediate water pipes that have been affected by radiological contaminants or attacks. Such pipes include, but are not limited to, any pipe system on military or naval vessels, cargo ships, cruise ships, yachts, etc; any pipe system associated with water supply systems for rural and/or urban areas, military bases, agricultural areas, food supplies and/or channels, etc; any stormwater, sewer or drainage pipe systems; etc. The present invention can also be used in combination with various methods of cleaning, including but not limited to sonic cleaning, vibrational cleaning, rotational cleaning, and chemical cleaning, such as surface bleaching. Cleaning methods (e.g., sonic, vibrational, rotational, chemical cleaning, etc.) of pipe systems may be combined with the use of one or more probes. The present invention may even be used to clean or remediate reservoirs, aqueducts, water treatment plants, etc. A. Clay Mineral The clay mineral 105 is a layer silicate having at least one tetrahedral sheet 505 and an octahedral sheet 510, as shown in FIG. 5. The tetrahedral sheet 505 is made up of a layer of horizontally linked, tetrahedral-shaped units coordinated to oxygen atoms and arranged in a hexagonal pattern. Each unit may include a central coordinated atom (e.g., Mg2+, Si4+, Al3+, Fe3+, etc.) surrounded by (and maybe bonded to) oxygen atoms that, in turn, may be linked with other nearby atoms (e.g., Mg2+, Si4+, Al3+, Fe3+, etc.). Fe+, etc.). The octahedral sheet 510 is made up of a layer of horizontally linked, octahedral-shaped units that may also serve as one of the basic structural components of silicate clay minerals. Arranged in an octahedral pattern, each unit may include a central coordinated metallic atom (e.g., Al3+, Mg2+, Fe3+, Zn2+, Fe2+, etc.) surrounded by (and maybe bonded to) a oxygen atoms and/or hydroxyl groups. The oxygen atoms and/or hydroxyl groups may be linked with other nearby metal atoms (e.g., Al3+, Mg2+, Fe3+, Zn2+, Fe2+, etc.). This combination may serve as inter-unit linkages that hold the sheet together. Within both tetrahedral and octahedral layers, O2− and/or OH− ions may be present. Where only one tetrahedral and one octahedral sheet are present for each layer, the clay is known as a 1:1 clay. Where, for each layer, there are two tetrahedral sheets with the unshared vertex of each sheet pointing towards each other and forming each side of the octahedral sheet 520, the clay is known as a 2:1 clay. As one embodiment of the present invention, either 1:1 or 2:1 clays, or a combination of the two, may be used. As another embodiment, the clays of interest generally fall within the silicate class. As yet another embodiment, the subclass may be phyllosilicates. Examples include, but are not limited to, those from the smectite group, such as montmorillonite, bentonite, beidellite, hectorite, nontronite, R0 illite-smectite, R1 illite smectite, sauconite, saponite, stevensite, etc. Montmorillonite may include, but is not limited to, montmorillonite, calcium-montmorillonite (Ca-montmorillonite), magnesium-montmorillonite (Mg-montmorillonite), sodium-montmorillonite (Na-montmorillonite), cesium-montmorillonite (Cs-montmorillonite), etc. Another example is illite-smectites. The crystalline structure includes a stack of layers interspaced with at least one interlayer site 525. Each interlayer site may include cations (e.g., Na+, K+, Ca2+, etc.) 515 or a combination of cations and water. A further example is the palygorskite group, such as palygorskite, sepiolite, tuperssuatsiaite, yofortierite, falconite, loughlinite, ferrisepiolite, Mn-sepiolite, Fe-palygorskite, Mn-palygorskite, etc. Depending on the composition of the tetrahedral 505 and octahedral 510 sheets, the layers may either have no charge or will have a net negative charge. If the layers are neutral in charge, the tetrahedral 505 and octahedral 510 sheets are likely to be held by weak van der Waals forces. If the layers are charged, this charge may be balanced by interlayer cations. In one embodiment, the clay mineral 105 is montmorillonite. Montmorillonite is a common smectite having one layer of aluminum atoms (i.e., middle layer) connected to two opposing layers of silicon atoms (i.e., outer layer) in a 2:1 layer structure. One version of the basic chemical formula, as a hydrous magnesium aluminum silicate, is MgAl2Si5O14.nH2O or MgO.Al2O35SiO2.nH2O, where n for both may vary from 5 to 8. H2O may be approximately 20.0 to 25.0 percent, of which half of this volume may be found at a temperature of about 100° C. Some calcium may replace some of the magnesium. Alternatively, the chemical formula for montmorillonite may also be written as:R0.33(Al1.67Mg0.33)Si4O10(OH2) (1).VI can be equal to −0.33; IV can be equal to 0. VI (denoted as such because of the 6-fold coordination) indicates the octahedral sheet and its charge. IV (denoted as such because of the 4-fold coordination) indicates the tetrahedral sheet and its charge. R is the exchangeable cation in the interlayer space. Variations of this chemical formula are also well known in the art. Montmorillonite is a chief constituent of bentonite, a clay-like material which may be formed by altering volcanic ash. Bentonite is the name of the rock which includes largely of the mineral montmorillonite. Besides bentonite, montmorillonite may also be found in granite pegmatites as an altered product of some silicate mineral. Montmorillonite may be a major constituent of shales and clay deposits in rocks that may be Jurassic in age or younger. In another embodiment, the clay mineral 105 is Na-montmorillonite. Na-montmorillonite is a 2:1 layer silicate which may be derived from bentonite. Two tetrahedral sheets, which may be composed predominantly of Si4+ tetrahedrons, may be bonded to an octahedral sheet, which may be composed of Mg2+, Al3+ and Fe3+ octahedrons. Each Si4+ tetrahedron may be coordinated to oxygen atoms. Each octahedron may be coordinated to oxygen atoms and/or hydroxyl groups. It should be noted that unless otherwise specified (e.g., distinguished separately), the description described herein with respect to montmorillonite also applies to M-montmorillonite, where M is an exchangeable cation, such as Cs and Sr. Naturally, montmorillonite tends to have defects in its crystal structure. Most evident is the turbostratic stacking of the 2:1 layers. This defect structure is believed to be the cause of the small crystallite size commonly observed. Having a flake-like shape resembling a corn flake, crystallites commonly vary in diameter from approximately 10 micrometers to approximately 0.01 micrometers. A distinguishing feature of montmorillonite is its ability to swell with water. After surpassing a certain swelling threshold, montmorillonite tends to slump and goes into pieces. Montmorillonite can expand from approximately 12 Å to approximately 140 Å in aqueous systems. Fundamentally, the reason for this expansion is that cation substitution (e.g., Mg2+ for Al3+) in the octahedral sheet combined with minimal cation substitution (e.g., Al3+ for Si4+) in the tetrahedral sheet may give rise to a low negative charge on the 2:1 layer. This result may cause the crystal structure to have weak bonding along (001). In essence, this effect may give rise to exchange sites between the 2:1 layer that may take up M+ or M2+ cations from aqueous solutions. The low negative charge on the 2:1 layer may enable cation exchange to take place. The charge deficiency in the 2:1 layer may need to be balanced by exchangeable cations. The quantity of cations required to create a net charge balance is called the cation exchange capacity. Commonly, the cation exchange capacity of montmorillonite varies between about 80 and about 150 meq/100 g. The pH dependence on this physical property may be absent or negligible. The internal charge deficiency of the clay mineral 105 may result in a net negative charge of the particle. Examples of exchangeable cations include, but are not limited to, sodium, calcium, magnesium, and potassium. Cation exchangeability tends to enable montmorillonite to remove heavy metals (e.g., Hg, Zn, Cd, Cu, Pb, As, etc.), alkaloids, alkalines, etc. from water. Removal of heavy metals is often associated with, inter alia, significant impacts, such as wastewater treatment. Additionally, ion exchange may also remove cationic and/or neutral organics, resulting in intercalate and/or polymer interaction. The combination of ion exchange capacity and capacity to swell may allow the material to form floccules with suspended solids that can be precipitated out. Removal of floccules may be achieved using a sorption based media, washing and/or centrifugation. These features, along with its chemical composition, are key elements to montmorillonite's exchange behavior with cesium and other cations. B. Liquids The water 110 used to create the aqueous clay suspension 115 may be tap water, distilled water, de-ionized water, etc. Where it is desirable to remove microbes from the clay mineral, the aqueous clay suspension 115 may be mixed with a liquid mixture. As an example, the liquid mixture may include part water 110 and some other liquid, such as hydrogen peroxide. Hydrogen peroxide may be advantageous for decontaminating the clay mineral 105 from bacteria, viruses, other microparasites, parasites, etc. Where the liquid mixture is part hydrogen peroxide and part water 110, the weight ratio of hydrogen peroxide to water 110 may range from about 1:99 to about 1:2. The present invention also allows a silver-based solution to be added. For instance, the silver-based solution may be silver nitrate solution (also referred to herein as one of the following: AgNO3, AgNO3 solution or AgNO3 solution (aq)). Alternatively, the silver-based solution may be silver hydroxide solution (also referred to herein as AgOH (aq)). Because AgOH (aq) has low solubility, it may be heated to allow for more silver ions in the solution. Heating may range, for example, from ˜100° F. to ˜180° F. As an exemplified embodiment, silver nitrate solution may be added to the aqueous slurry after the radionuclide containment composition 125 has come in contact with a radioactive material to create an aqueous slurry S215. The product may be referred to as a suspension. In another embodiment, the AgNO3 solution may also be used as a pretreatment step before sequestration by the clay mineral 105 and water 110 mixture for discovering a stock of poisonous or radioactive materials. In this instance, the AgNO3 solution may be applied to the clay mineral 105. After this application, water 110 may then be added to this pretreated clay mineral 105 to form the aqueous clay suspension 115. The aqueous clay suspension 115 may be refined 120 by using sieves to filter coarse materials. After filtering, the resulting product (i.e., radionuclide containment composition 125) may be applied to a radioactive material. To the aqueous slurry that may be formed, a silver-based solution may be added. The minimum ratio of silver-based solution to aqueous slurry is about 1:20. As one embodiment, the ratio of silver nitrate solution to aqueous slurry is 1:4. As an embodiment, adding a silver based solution to the aqueous slurry or as a pretreatment step may help remove chloride ions. These chloride ions may be found where the radioactive materials are present or have been dispersed, such as pipes, water aqueducts, reservoirs, warehouses, ground, public forums, etc. Because silver nitrate has inherent antibacterial/antiseptic properties, it may also serve as an antibacterial/antiseptic agent. The addition of AgNO3 solution may produce sodium nitrate as a byproduct. To remove the sodium nitrate, the suspension may be heated. Temperature may vary. For example, the temperature may be approximately 475° F. The length of heating may also vary. For example, heating may take 3 hours. C. Filters Once the mixture is created and allowed to sit, the aqueous clay suspension 115 may be refined by using a filter 120, S210, such as a sieve. Filtering may help remove coarse material. One or more containers (e.g., beaker, bucket, silo, etc.) may be used to receive the filtered aqueous clay suspension 115. In general, where a sieve is exercised, smaller sieve apertures tend to result in a processed suspension that is more uniform with less residual coarse material. Hence, embodied sieve aperture sizes may range from 300 μm to <38 μm. A minimum of 5 μm appears to be the functional limit for producing fluids. Although some fragments of coarse material (or fractions) may penetrate through the filter, they contribute minimally to the aqueous clay suspension 115 being employed. Nevertheless, the penetrable fragments may be used for forensic purposes to identify original materials. The makeup and grain size of the filtered coarse fractions may be analyzed to determine the composition of the clay mineral 105. Analysis may be achieved by, for instance, back scatter scanning electron microscopy. Having mineralogical data may provide some insight into the nature of the clay minerals used. D. Radionuclide Containment Radionuclides from radioactive materials may be contained by contacting the radioactive material with a radionuclide containment composition to form an aqueous slurry. It should be noted that it is alternatively possible to contact the radioactive material with an aqueous clay suspension 115 to form the aqueous slurry. Generally, this aqueous clay suspension 115 is a processed, uniform suspension (having a possible gel-like consistency) comprising a clay mineral 105 mixed with water 110. The aqueous clay suspension 115 may be refined 120 to filter and remove coarse materials S210. This filtering can generate a smoother consistency. If refined, the composition may be referred to as a radionuclide containment composition 125. At the point of contact between the radioactive material and aqueous clay suspension (refined or unrefined) 115, S215, radionuclides may be absorbed by the aqueous clay suspension 115. The result may be an aqueous slurry. The radioactive material may include, but are not limited to, compounds having at least one of the following radionuclide: 241Am, 134Cs, 137Cs, 60Co, 131I, 192Ir, 238Pu, 239Pu, 240Pu, 242Pu, 90Sr, 235U and 238U. The radioactive material may also include a radioactive chloride, as discussed earlier. For example, as an embodiment, the radioactive material is 137CsCl. Cesium has an affinity to bond with chloride ions. When the two ions are combined, a crystallized powder is formed. Combining 137Cs ions and chloride ions can produce 137CsCl. As another embodiment, the radioactive material is CsCl, where the radionuclide is a radioactive chloride, such as 36Cl. As another embodiment, other radioactive materials involving radioactive chloride may include, but are not limited to, CsCl, RaCl2, SrCl2.6H2O, BaCl2, HgCl, HgCl2, PbCl2, CdCl2, ZnCl2, CoCl2, etc. Additionally, other nonlimiting examples of poisonous or radioactive chloride compounds include uranium, actinide and lanthanide chlorides. As another embodiment, the clay mineral 105 used to contain 137CsCl may be any smectite mineral. Using montmorillonite as an exemplified embodiment of smectite and 137CsCl as the exemplified radioactive material, these selections may be based on a variety of factors. One, montmorillonite is generally expandable. Two, because of montmorillonite has the ability to exchange alkali cations in aqueous systems, Cs+ cations may be readily exchanged when these two are combined. Commonly, when Cs is exchanged, Cs is irreversibly sorbed on smectite minerals. This interaction can be exploited for transporting and storing 137CsCl and could be used to respond to 137CsCl release. Three, there are many sources of montmorillonite. Four, montmorillonite is comparatively low in cost. The radionuclide containment composition 125 may be applied to powder or aqueous solutions of radioactive materials using numerous techniques. Techniques include, but are not limited to, contacting, spraying (e.g., using a spray bottle, squirt gun, hose, etc.), pouring, covering, mixing, etc. Because of the rheological properties of the aqueous clay suspension 115, little to no agitation and/or dispersal of the radioactive material should occur. Optionally, montmorillonite may be pretreated with aqueous salt solution, such as NaCl, NaOH, and NaClO4. Where NaCl is used for pretreatment, montmorillonite's sorption of Na+ cations is expected to produce Na-montmorillonite. Having an aqueous or gel-like consistency, this exchanged composition may be washed to remove excess aqueous salt solution. Additionally, the exchanged composition may be tested for residual anions by using a precipitating agent (e.g., silver nitrate, etc.). The radionuclide containment composition 125 may be applied to powder or aqueous solutions of radioactive materials using numerous techniques. Techniques include, but are not limited to, contacting, spraying (e.g., using a spray bottle, squirt gun, hose, etc.), pouring, covering, mixing, etc. Because of the rheological properties of the aqueous clay suspension, little to no agitation and/or dispersal of the radioactive material should occur. Using 137CsCl for demonstrative purposes, as a result of applying the aqueous clay suspension 115 onto 137CsCl, the aqueous clay suspension 115 may directly and irreversibly absorb 137Cs cations. It may be the case where exchange occurs spontaneously or essentially immediately. A dramatic change in the rheological properties should occur where the aqueous/gel-like consistency of the radionuclide containment composition 125 disappears and becomes a waxy paste in the Cs-montmorillonite form. In general, a waxy paste, or alternatively aqueous slurry, may be formed after a radionuclide containment composition contacts a radioactive material. This aqueous slurry may then be contacted with a sorption based media. This latter contacting is a different containment stage that is separate from the initial containment stage (i.e., the former contacting). To assist this latter contacting, a probe may be used. Examples of probes include sonic and/or ultrasonic probes, magnetic probes, electrical probes, mechanical probes (e.g., rods, plunging devices, etc.), oil and similar oily substances, detergents, pressurized air, pressurized water, etc. Additionally, gravity or gravitational probes may be used. Any combination of probes may also be used. E. Sorption Based Media Sorption based media is a composition used to remove and sequester radionuclides captured by the aqueous slurry. Sequestering may be achieved by chemical ion exchange with the radionuclides (which may be found in the aqueous slurry and/or radioactive material), mechanical separation of floccules (which may be formed when the radionuclide containment composition contacts a radioactive material), or a combination of the two. The sorption based media may include one or more different clay minerals. In one embodiment, a clay mineral from the palygorskite-sepiolite mineral group (also sometimes referred to as palygorskite group), such as palygorskite, may be used as the primary mineral for the sorption based media. Also known as attapulgite, palygorskite is a 2:1 clay mineral that is known to have a high sorption capacity for organic molecules. Overall, palygorskite comprises fibrous felted masses as well as disseminated grains and platy crystals. The tetrahedral sheet tends to be continuous; the octahedral sheet tends to be discontinuous. The general formula can be presented as:(Mg5−y−zR3+y)(Si8−xR3+x)O20(OH)2(OH2)4R2+(x−y+2z)/2(H2O)4 (2)where R2+(x−y+2z)/2 and (H2O) represent the charge balancing cations and water in the rectangular cavities, y is the fraction of Mg substituted by Al in the octahedral sheet, and x is the fraction of Si substituted by Al in the tetrahedral sheet. Isomorphous substitution is often relatively low in the tetrahedral sheet, with Al occupying 0.01 to 0.09 of 8 tetrahedral sites. On the contrary, isomorphous substitution is relatively high in the octahedral sheet, with Al occupying 28-59% of the octahedral sites. Other cations, including but not limited to Fe2+, Fe3+ and Mn are also present. Other examples of clay minerals from the palygorskite group that can be used as the sorption based media include, but are not limited to, palygorskite, sepiolite, tuperssuatsiaite, yofortierite, falconite, loughlinite, ferrisepiolite, Mn-sepiolite, Fe-palygorskite, Mn-palygorskite. It is also possible that as another embodiment, other clays that may be used as the sorption based media fall within the silicate class. As yet another embodiment, the subclass may be phyllosilicates. Examples include, but are not limited to, those from the smectite group. In an embodiment, the sorption based media may comprise palygorskite-rich media made of ˜50%-˜80% palygorskite. In addition, the sorption based media may also comprise ˜10%-40% in other minerals, such as montmorillonite, illite and kaolinite. Furthermore, ˜10% (or less) in impurities, such as quartz, feldspar and titanium oxide, may also exist in the sorption based media. Having a mixture of clays may aid or enhance the radionuclide sorption ability. The sorption based media may be housed in a separated compartment or container. To demonstrate the stability of aqueous clay suspension 115 (both refined and unrefined) when applied to a radioactive chloride material, such as 137CsCl, which is a typical substance encountered in a dirty bomb, the aqueous clay suspension 115 may be aged. There is no restrictive time limit in the aging process since the aging process may, depending on a user's desires, last from minutes to years. For instance, the aging process may last for 10 months. The pH values for reacted aqueous clay suspension 115 may vary from ˜3 to ˜4.65. Dissolution of the clay mineral 105, such as montmorillonite, is a possibility under these pH conditions. A new rate law described by Keren Amram and Jiwchar Ganor may be applied under these pH conditions. Cf. Amram, K. and Ganor, J., 69 Geochimica et Cosmochimica Acta 2535-2546 (2005). Their rate law for montmorillonite (and also broadly applicable to smectites) is:Rate=220·e−17460/RT·(3×10−6·e10700/RT·aH+)/(1+3×10−6·e10700/RT·aH+) (1)Id. Their work may serve as a worst case scenario for dissolution for the present invention because their dissolution investigation is set up based on flow-through reactor experiments. In a vast majority of applications, the present invention may be used in batch-mode, where the material will be placed in containers. Amram and Ganor's rate law tends to be appropriate for the present invention because, analogously, they used montmorillonite with a similar chemical composition similar to the present invention. Furthermore, Amram and Ganor found that dissolution rates were not affected by the addition of up to 0.3 M NaNO3, a compound that is likely to be produced in the present invention from the exchange of Na+ in the starting montmorillonite and the resulting NO3−. Amram and Ganor performed experiments using flow-through reactors in thermostatic water at temperatures of 25° C., 50° C. and 70° C.±0.1° C. Cf. Amram, K. and Ganor, J., 69 Geochimica et Cosmochimica Acta 2535-2546 (2005). The dissolution rates obtained were based on the release of Si and Al at a steady state. Id. Their results indicate dissolution rate increases with temperature and decreases with increasing pH. Id. They developed a specific model to describe the effect of temperature and pH on the dissolution of smectite. Id. Their model is linearly proportional to concentrations of absorbed protons on the surface of the mineral. Id. They also described proton sorption using a Langmuir adsorption isotherm. Id. The dissolution rates obtained by Amram and Ganor varied from 2.6±0.5×10−12 mol g−1s−1 to 2.8±0.5×10−12 mol g−1s−1. Cf. Amram, K. and Ganor, J., 69 Geochimica et Cosmochimica Acta 2535-2546 (2005). Therefore, the total range possible for the rate of dissolution of montmorillonite is approximately 2.1×10−12 mol g−1s−1 to 3.3×1012 mol g−1s−1. These results equate to a range of mass loss (i.e., in mol g) between approximately 0.000066 and 0.00011 per year. A conservative estimation based on these numbers indicates that the montmorillonite will be stable for at least 100 years. Volclay SPV 200, an American Colloid product, is placed in aqueous suspension using a ratio range of 20 oz to 60 oz volume Volclay 200 to 5 gallons of water 110. Optionally, prior to saturation with water 110, Volclay SPV 200 may be pretreated with aqueous NaCl solution. Alternatively, the Volclay SPV 200 may be pretreated with either aqueous NaOH or NaClO4. This process may create an exchanged composition wherein the ions in the interlayer of montmorillonite may be exchanged with Na+ (aq) from the aqueous salt solution. Saturation was allowed to occur overnight. After saturation, the exchanged composition was washed. The process was repeated 5 times to allow for full exchange to take place. Afterwards, the exchanged composition can be washed and tested for residual anions from the aqueous salt solution. The material is mixed mechanically for 5 minutes and is allowed to stand overnight. The suspension is then filtered through a 45 μm metal screen to remove coarse material. The filtration process breaks up the material and imparts a uniform suspension. For preparing and verifying the properties of the radionuclide containment composition, the present invention also relies on the teachings of PCT Patent Application No. PCT/US2006/019763 to Krekeler et al., filed on May 22, 2006, entitled “Counter Weapon Containment” and PCT Patent Application No. PCT/US2006/035844 to Krekeler et al., filed on Sep. 14, 2006, entitled “Secondary Process for Radioactive Chloride Deweaponization and Storage.” A. Properties of Starting Material Grain size analysis was performed on the raw starting material (Volclay SPV 200, American Colloid) using standard mechanical sieves. Approximately 100 grams of raw material was analyzed using 8″ sieves using fractions between 300 μm and 38 μm. The percentage that passed the 38 μm sieve was included in the analysis. Sieve stacks were shaken mechanically for 15 minutes. Fractions captured in each sieve were then weighed. Normalized percentages of each size fraction were calculated based on the total sum of mass retained in each sieve. Differences between total mass analyzed and total mass retained varied from 3% to 7%. Grain size analysis indicates that for most analyses, a single normal distribution of particles does not exist in the starting material. The variability in the size distribution of particles is attributed to variation in processing, or natural variability of source material in the mine at the manufacturer's source. The modes at 180 μm, 106 μm, 75 μm, and <38 μm are common. Analyses of grain size distribution at various modes are shown in TABLE 2. These analyses have single and multiple modes. TABLE 2Grain Size Distribution by Normalized Percentages for Analyses 1-1012345678910300 μm0.110.140.060.221.620.670.370.070.0700.051250 μm0.220.360.400.780.300.210.520.430.0870.174212 μm11.847.530.4314.790.360.321.737.660.2100.245180 μm7.6830.140.5826.610.730.533.7623.540.5760.562150 μm3.3019.440.8916.881.351.219.6117.200.9601.094125 μm13.1813.011.6213.162.212.2316.7916.302.1131.809106 μm14.100.782.508.093.243.0224.7114.002.2353.741 90 μm0.755.318.011.265.586.950.660.4720.08013.493 75 μm2.7611.7712.602.8429.9230.704.510.0913.23613.544 63 μm5.131.7126.663.8921.4823.877.442.034.2266.930 53 μm14.226.8824.957.6013.3918.7414.539.2111.05315.476 43 μm11.672.1714.943.5410.296.608.233.5012.13512.144 38 μm9.880.775.960.306.803.077.135.5115.87214.535<38 μm5.160.000.400.022.721.900.000.0017.14716.202Sum100.00100.00100.00100.00100.00100.00100.00100.00100.00100.00 The raw material used to make the aqueous clay suspension 115 (e.g., uniform aqueous Na-montmorillonite suspension) is a processed bentonite. The coarse fraction of the raw starting material used to make this technology was investigated using back scatter scanning electron microscopy as a means to characterize the raw material. The mineralogical characteristics of the coarse fraction provide some insight into the nature of the raw material. However, the coarse fraction has a very minimal role in contributing to the properties of the aqueous clay suspension 115. Because the raw material is processed, some small fragments of the coarse fraction minerals may enter the technology product. Therefore, the data on the coarse fraction is useful for forensic purposes once the aqueous clay suspension 115 is deployed. The coarse mineral data also serves as a characteristic of the original material. Coarse fraction mineral grains varied between very angular to rounded shapes. However, most grains are very angular to angular. Minerals commonly observed are plagioclase, biotite, zircon, quartz, K-feldspar, calcite, and iron oxides. PbS (galena) was also observed. There are two general groups of minerals based on geologic processes. Plagioclase, biotite, zircon, and quartz are volcanic in origin while calcite, K-feldspar, iron oxides, and galena are authigenic in origin. K-feldspar (sanidine) can also be volcanic in origin. Aggregates of calcite and K-feldspar were observed, and galena was observed with these two minerals. Such authigenic mineral associations have been observed in Ordovician bentonites. Energy dispersive spectroscopy (EDS) spectra analyses indicate that the biotite is intermediate in composition with respect to Fe and Mg concentrations. There is also Ti and Cl in the biotite. EDS analyses indicate that the plagioclase is commonly labradoritic to albitic in composition. Zircon crystals are end member composition and no Hf was detected. The detection limit is approximately 1%. B. Grain Size Analysis of the Aqueous Clay Suspension For transmission electron microscopy investigation, grain mounts were prepared of the Na-montmorillonite using alcohol as a dispersing medium. Analyses were prepared on 300 mesh hole carbon Cu grids. Analyses were investigated using a 300 kV JEM 3010 transmission electron microscope (TEM) and a 200 kV 2010 scanning transmission electron microscope (SEM). TEM investigations indicate that the montmorillonite phase used in the process appears dominantly composed of montmorillonite particles (˜>95%) and with a lesser amount of silica particles. The morphology of the montmorillonite particles are generally described based on the classification outlined in Güven. See Güven, N. 19 Smectites 495-559 (1988). The montmorillonite from the suspension and process may comprise commonly of foliated lamellar aggregates. Such aggregates may compose about 40 to 75% of the montmorillonite particles. Subhedral platelets and compact subhedral lamellar aggregates may occur as well. Both may make up about 10 to 40% of the montmorillonite particles. Subhedral lamellar aggregates may also occur. These may make up about 5 to 10% of the montmorillonite particles. Foliated lamellar aggregates may vary in diameter from ˜0.2 to >5.0 μm. Subhedral lamellar aggregates may vary in diameter from ˜0.1 to ˜3.5 μm. Subhedral platelets may vary in diameter from ˜0.5 to >5.0 μm. SAED patterns taken along 00 l on discrete particles show concentric rings. Discrete diffraction spots tend to occur, owing to localized regular stacking but are typically not abundant or well ordered. These patterns appear consistent with turbostratic stacking of the 2:1 layers in commonly observed montmorillonite. Diffraction patterns may range from nearly homogenous rings to rings with about 40% spots. EDS spectra were collected using the 300 kV JEM 3010 TEM. EDS spectra were collected using spot size 2-3. Spectra with Si peaks greater than 100 counts were deemed significant. Variation in intensity was related to apparent thickness. The higher contrast particles appeared to produce more intense spectra. Analyses were performed on the center of particles. The elements observed include Si, Al, Fe, Ca, K, Na and Mg. Systematic drift in EDS analyses occurred. SiO2 concentrations tend to be elevated and Na2O concentrations may be lower than actual concentrations, owing to diffusion in either the solid state or release of hydrated interlayer sodium cations. EDS chemical composition data (weight percent of oxides for each experimental run) are provided in TABLE 3. The minimum, maximum, median, variance and standard deviation of the elements are presented in TABLE 4. FIGS. 6-12 illustrate some TEM and associated SAED images of montmorillonite particles. FIGS. 13-16 illustrate some TEM images of montmorillonite particles. FIGS. 17-19 illustrate plot concentrations of oxides from these tables. TABLE 3Chemical compositions of individual unreacted montmorillonite particleswith descriptive statisticsAnaly-sisSiO2Al2O3Fe2O3MgOCaONa2OK2Ototal162.5525.613.295.100.802.590.06100.00258.4226.912.227.651.013.740.05100.00363.9023.743.224.401.263.400.08100.00457.9927.633.156.840.703.600.08100.00558.2129.302.665.880.693.240.03100.00684.8510.021.162.320.501.140.00100.00758.7927.803.426.190.673.100.03100.00856.5028.352.677.650.744.080.01100.00954.4029.752.358.380.874.140.11100.001063.3425.343.654.051.332.210.07100.001162.2125.143.994.830.782.970.08100.001257.9327.933.306.840.733.150.12100.001359.2427.483.206.180.623.240.05100.001462.3024.913.865.110.782.840.20100.001562.3426.333.154.730.972.440.05100.001662.6626.383.134.150.742.890.04100.001763.6724.823.194.300.992.900.13100.001864.0522.832.006.960.703.390.07100.001956.1328.672.797.740.703.970.00100.002056.8027.412.638.330.773.960.11100.002158.3228.822.326.030.663.810.06100.002258.2728.012.956.640.743.320.07100.002357.9928.542.806.720.693.200.06100.002455.8828.582.308.270.764.190.04100.002556.4127.502.498.370.844.350.05100.002657.8928.522.756.610.733.500.02100.002762.7925.163.165.031.042.750.08100.002855.9828.032.497.870.994.560.08100.002962.7426.612.653.981.092.880.05100.003056.2628.562.228.000.694.190.09100.003157.9527.372.377.900.623.740.05100.003262.8724.273.434.810.873.560.18100.003357.3927.502.557.570.744.250.00100.003458.6828.182.896.410.663.120.07100.003560.6026.253.075.580.733.670.09100.003656.9927.823.177.300.913.740.06100.003757.7827.673.006.920.943.550.14100.003856.6027.523.607.270.973.920.12100.003980.9612.741.832.030.731.610.12100.004062.7924.513.235.151.043.190.10100.004157.8926.893.177.190.873.920.07100.004262.0623.745.394.550.813.350.10100.004365.2922.554.084.251.182.480.18100.004456.6927.203.078.080.594.280.09100.004557.8227.182.657.750.803.670.13100.004664.9723.743.153.931.222.610.39100.004759.0927.902.436.620.703.240.02100.004858.9127.822.636.760.673.120.09100.004963.4723.815.183.651.052.710.12100.005054.8328.353.587.950.904.320.08100.00 TABLE 4Summary of Weight % of Oxides in MontmorilloniteSiO2Al2O3Fe2O3MgOCaONa2OK2OCs2OClMinimum55.4015.871.321.290.000.400.009.090.42Maximum64.0823.153.175.790.141.892.1718.772.18Median58.0019.921.934.450.060.880.0213.360.87Variance3.071.830.141.220.000.130.404.400.12St. Dev.1.7511.35120.3791.110.0360.3620.63522.0970.352 FIG. 6 shows a representative TEM image (top image) of lamellar aggregate of montmorillonite with characteristic irregular terminations of particles. This particle has a diameter of ˜4.5 μm. Folded regions can be as long as ˜3 μm. The SAED pattern (bottom image) is a very diffuse SAED pattern of (hk0) reflections showing a high degree of structural disorder. The few diffraction spots which do occur are heavily streaked and rings are weak. The pattern indicates turbostratic stacking. FIG. 7 shows a representative TEM image (top image) of particle exhibiting some straight edges. This texture is intermediate between platy morphologies and lamellar aggregates commonly observed. The SAED pattern (bottom image) is a very diffuse SAED pattern showing a high degree of structural disorder. The few diffraction spots which do occur are heavily streaked are of the (hk0) reflections. The well developed rings are indicative of turbostratic stacking. FIG. 8 shows a representative TEM image (top image) of a subhedral platy particle of montmorillonite showing some near straight edge terminations. The particle is ˜450 nm in diameter. An aggregate of silica particles is adjacent on the right of the particle. Smaller platy montmorillonite particle can be observed in the image will diameters between ˜50 nm and ˜120 nm. The SAED pattern (bottom image) taken along (hk0) for the subhedral particle in the lower center of the image above showing diffraction rings indicative of a high degree of rotational turbostratic stacking disorder with some discrete spots. FIG. 9 shows a representative TEM image (top image) of lamellar aggregate of montmorillonite used in fluid. Central portion of image shows an example of an anhedral lamellar aggregate with irregular morphology. The diameter of the particle shown is ˜1.8 μm. The particle is surrounded by smaller discrete particles with a more platy morphology. The SAED pattern (bottom image) taken along (hk0) for the lamellar aggregate particle in the image above showing diffraction rings indicative of a high degree of rotational turbostratic stacking disorder with minor discrete spots. FIG. 10 shows a representative TEM image (top image) of lamellar aggregate of montmorillonite used in fluid. Central portion of image shows an example of an anhedral lamellar aggregate with irregular morphology. The particle is surrounded by smaller discrete particles. The SAED pattern (bottom image) taken along (hk0) for the large particle in the image above showing diffraction rings indicative of a high degree of rotational turbostratic stacking disorder with minor discrete spots. FIG. 11 shows a representative TEM image (top image) of lamellar aggregate of montmorillonite used in fluid. Central portion of image shows an example of a aggregate with a complex morphology. Near straight edge terminations on one side of the particle are present with anhedral edge terminations occurring on the opposite side of the particle. The larger particle in the center is surrounded by smaller subhedral to anhedral particles that are ˜0.1 μm to ˜0.5 μm in diameter. Particle morphologies such as these are common in the montmorillonite used in the fluid. The SAED pattern (bottom image) taken along (hk0) for the large particle in the image above showing some discrete spots but still a large degree of rotational turbostratic stacking disorder. FIG. 12 shows a representative TEM image (top image) of lamellar aggregate of montmorillonite used in fluid. Upper portion of image shows an example of a pseudo rhombohedral morphology which is sometimes observed. Near straight edge terminations shown elsewhere in this image are also common. Subhedral lamellar aggregates are common in the montmorillonite used in the fluid. The SAED pattern (bottom image) taken along (hk0) for the image above showing some discrete spots but still a large degree of rotational turbostratic stacking disorder. FIG. 13 shows a representative TEM image from grain mount showing morphology of montmorillonite particles. Particles are commonly ˜0.3 μm to ˜3.0 μm in diameter and are lamellar aggregates to pseudo platy in morphology. Darker particles tend to be lamellar aggregates while light particles dominantly are pseudo-platy to platy in morphology. Silica particles are of medium contrast and are rounded or rounded aggregates. FIG. 14 shows a representative TEM image from grain mount showing morphology of montmorillonite particles. Particles are commonly ˜0.80 μm to ˜3.0 μm in diameter and are lamellar aggregates to pseudo platy in morphology. Silica particles are of medium contrast and are rounded or rounded aggregates. FIG. 15 shows a representative TEM image from grain mount showing morphology of montmorillonite particles. Particles are commonly ˜0.25 μm to ˜3.0 μm in diameter and are lamellar aggregates to pseudo platy in morphology. Silica particles are of medium contrast and are rounded or rounded aggregates. FIG. 16 shows a representative TEM image from grain mount showing morphology of montmorillonite particles. Four larger particles with darker contrast which are ˜0.5 μm to ˜1.5 μm in diameter are shown, which are lamellar aggregates. Smaller montmorillonite particles ˜0.1 μm to ˜0.5 μm in diameter occur throughout the image. Silica particles are of medium contrast and are rounded or rounded aggregates. FIG. 17 shows an X-Y plot of the chemical compositional space (Al2O3 and SiO2 in wt %) of montmorillonite used. Most of the particles have a composition with an SiO2 content between ˜50 and ˜65 wt %. The Al2O3 content commonly falls between ˜20 and ˜32 wt %. The linear relationship shows that there is systematic variation between these two components. FIG. 18 shows an X-Y plot of the chemical compositional space (Al2O3—Fe2O3 in wt %) of montmorillonite used. Fe2O3 content in the montmorillonite is commonly between ˜1 and ˜5.5 wt %. This range indicates that the montmorillonite used varies from near ideal compositions of montmorillonite to intermediate compositions between montmorillonite and nontronite. Al2O3 content commonly falls between ˜20 and ˜32 wt % but may be as low as ˜10% in some particles. This compositional field in part defines 2:1 layer compositional characteristics of the technology. FIG. 19 shows an X-Y plot of the chemical compositional space (MgO—Fe2O3 in wt %) of montmorillonite used. MgO content varies from ˜2.0 to ˜8.5 wt %. Mg and Fe are interpreted to be octahedral cations and can occur in the octahedral sheet in the 2:1 layer. This compositional field in part defines 2:1 layer characteristics of the technology. Although not likely, Fe3+ may substitute in the tetrahedral layer as well and this may explain some of the variation observed. C. Properties and Behavior of Reacted Aqueous Slurry In one experiment, ˜100 ml of the aqueous clay suspension comprising of a montmorillonite-based fluid was mixed with ˜800 ml of 0.25 M solution of CsCl to sequester 133Cs+ aqueous cations. Initially, when a small amount of montmorillonite-based fluid was introduced to the CsCl solution, immediate flocculation occurred and continued to occur. Phase separation began within ˜30-˜45 seconds as floccules began settling to the bottom. After a few minutes a large portion of the floccules separated from the solution. In other experiments, repeated feasibility tests show that a small pile of CsCl that is ˜1 inch in diameter can be contained by ˜20 to ˜30 pumps of aqueous clay suspension. The spraying of the suspension on the CsCl powder does not agitate and disperse the powder. This effect is due to the rheological properties of the suspension. The suspension self aggregates and seals the pile. The mixture can then be vacuumed or removed. Upon exchange with Cs+, visible changes in the physical properties occur. After exchange, the color of the aqueous clay suspension turns to Munsell values of 5 Y 7/2, 5 Y 7/3, 5 Y 6/2, 5 Y 6/3 or intermediate colors between those values. A dramatic change in the rheological properties occurs where the gel-like consistency of the Na-montmorillonite completely disappears and becomes a waxy paste in the Cs-montmorillonite form. The color of the aqueous clay suspension as compared to a Munsell color chart varies slightly from 2.5 Y 6/3 to 2.5 Y 6/2. The color is generally uniform within analyses and is not streaked. Each of the thirty analyses of Cs-montmorillonite was analyzed for weight percentage of oxides using EDS. For transmission electron microscopy investigation, grain mounts were prepared of the Cs-exchanged montmorillonite using alcohol as a dispersing medium. Analyses were prepared on 300 mesh hole carbon Cu grids. Analyses were produced using a 300 kV JEM 3010 TEM. The weight percentages of oxides of each experimental run and the summary are respectively shown in TABLES 5-6. FIG. 20 illustrates some TEM and associated SAED images of Cs-reacted montmorillonite particles. TABLE 5Chemical compositions of Cs-reacted montmorillonite particles withdescriptive statistics.AnalysisSiO2Al2O3Fe2O3MgOCaONa2OK2OCs2OClTotal156.0519.303.171.290.000.650.0018.770.77100.00257.2920.031.923.260.001.140.0215.530.81100.00358.5220.052.054.840.090.750.0812.630.99100.00460.3319.732.505.310.050.400.0410.930.71100.00559.0820.112.364.660.060.600.0012.400.73100.00656.0521.522.315.790.021.890.0011.910.51100.00760.0319.881.675.150.101.152.119.090.82100.00858.6419.952.154.490.050.810.0012.901.01100.00958.9019.761.944.130.110.920.5212.800.92100.001060.6019.351.544.960.031.242.179.270.84100.001160.0419.241.604.440.051.392.0710.400.77100.001264.0815.871.895.300.070.570.1811.300.74100.001356.0621.741.965.410.001.530.0212.231.05100.001458.0019.782.234.460.031.130.0013.291.08100.001559.2918.831.974.210.080.700.0213.591.31100.001658.4519.112.002.090.040.730.0216.191.37100.001756.8721.041.915.480.111.380.0811.951.18100.001855.4021.161.734.980.071.880.0213.621.14100.001958.8719.031.714.620.071.140.0113.431.12100.002058.3818.982.163.230.140.710.2614.841.30100.002157.9519.291.962.970.081.150.0514.372.18100.002257.9919.761.922.120.040.830.0715.671.60100.002357.6520.711.883.380.020.800.0114.910.64100.002457.3921.721.454.790.090.860.0812.720.90100.002557.2720.951.583.300.030.910.0115.130.82100.002658.6019.502.303.860.090.890.0114.330.42100.002757.5320.391.793.150.050.850.0015.480.76100.002856.7423.152.633.700.120.580.3511.601.13100.002956.9221.531.723.450.060.860.5114.320.63100.003056.3422.271.324.530.060.890.0013.900.69100.00 TABLE 6Summary of Weight % of Oxides in MontmorilloniteSiO2Al2O3Fe2O3MgOCaONa2OK2OCs2OClMinimum55.4015.871.321.290.000.400.009.090.42Maximum64.0823.153.175.790.141.892.1718.772.18Median58.0019.921.934.450.060.880.0213.360.87Variance3.071.830.141.220.000.130.404.400.12St. Dev.1.7511.35120.3791.110.0360.3620.63522.0970.352 FIG. 20 shows representative TEM images (left) and respective SAED patterns (right) of Cs-reacted montmorillonite particles. Magnification is a 6,000× for all images. Particles shown are largely lamellar aggregates. SAED pattern show variation with some patterns being overall similar to un-reacted montmorillonite have turbostratic rings being well developed and lacking a large number of discrete diffraction spots such as SAED patterns for A and C. Other particles have very discrete diffraction spots after reaction with Cs+ such as those in B and D. The Discrete spots are interpreted as a result of Cs+ cations exchanging into specific discrete crystallographic sites in the hexagonal rings of between the tetrahedral sheets in the montmorillonite structure. Similar to the CsCl experiments above, the aqueous clay suspension may be applied to SrCl2.6H2O. In one experiment, the aqueous clay suspension comprising of montmorillonite-based fluid was introduced to ˜0.25 M solution of SrCl2.H2O. After a few minutes, the introduced montmorillonite-based fluid showed flocculation. A close inspection reveals that floccules are well-formed and discrete with diameters of ˜1-˜2 mm. Time lapse here is ˜15 mins. For transmission electron microscopy investigation, grain mounts were prepared of the Sr-exchanged montmorillonite using alcohol as a dispersing medium. Analyses were prepared on 300 mesh hole carbon Cu grids. Analyses were investigated using a 300 kV JEM 3010 TEM and a 200 kV 2010 SEM. The weight percentages of oxides of each experimental run and the summary are respectively shown in TABLES 7-8. FIG. 21 illustrates some TEM and associated SAED images of Sr-reacted montmorillonite particles. TABLE 7Chemical compositions of Cs-reacted montmorillonite particles withdescriptive statistics.AnalysisSiO2Al2O3Fe2O3MgOCaOSrONa2OK2OTotal157.4023.193.624.850.559.261.140.00100.00256.8024.463.815.130.397.441.970.00100.00358.7022.294.175.780.367.221.470.01100.00460.7223.133.115.610.375.581.480.01100.00558.2823.754.104.730.437.701.020.00100.00658.2723.853.274.540.468.680.930.00100.00761.8622.062.755.460.376.341.100.07100.00860.4922.592.765.740.386.261.770.01100.00959.3923.252.575.910.446.741.710.00100.001061.2123.122.904.820.386.281.300.00100.001159.0523.113.475.510.376.881.620.00100.00 TABLE 8Summary of Weight % of Oxides in MontmorilloniteSiO2Al2O3Fe2O3MgOCaOSrONa2OK2OMin-56.8022.062.574.540.365.580.930.00imumMax-61.8624.464.175.910.559.261.970.07imumMedian59.0523.133.275.460.386.881.470.00Var-2.600.480.310.230.001.210.110.00ianceSt. Dev.1.6120.6940.5580.4820.0571.0990.3390.021 FIG. 21 shows representative TEM images (left) and respective SAED patterns (right) of Sr-reacted montmorillonite particles. Magnification is 6,000× for all images. Particles shown are largely lamellar aggregates. SAED pattern show variation with some patterns being overall similar to un-reacted montmorillonite have turbostratic rings being well developed and lacking a large number of discrete diffraction spots. The SAED pattern for B shows some discrete poorly formed spots in the rings. D. Sorption Based Media 1. Pre-Contact with Aqueous Slurry The sorption based media may comprise of any clay material from the smectite class. As an exemplified embodiment, the sorption based media comprises palygorskite-rich media. The palygorskite-rich media can be granulated in form from particle sizes of ˜10 micrometers to ˜1 cm. Particles are commonly angular but rarely rounded particles do occur. In addition, as another embodiment, the palygorskite (as well as other minerals that may be used as the sorption based media) may be pretreated with a plurality of cations, such as Na+, Ca2+, Mg2+, etc. Pretreating the sorption based media with various cations can help facilitate the exchange of cations with radionuclides. Particle size distribution tends to allow the media to be modified to change the permeability. For example, RVM 420 formulation (a granulated product obtainable from Oil Dri Corporation of America of Chicago, Ill.) in unmodified form has a range of permeability coefficients that can vary from ˜2.55 to ˜4.29 cm/s. By modifying grain size, the permeability coefficient can be modified. For example, sieved material <1.18 mm in average diameter has permeability coefficients that can vary from ˜1.14 to ˜3.46 cm/s. Permeability tests and results can be seen in TABLES 9-16. TABLE 9Permeability Tests of Unmodified DataT0T1Vol0Vol1Height0Height1h0 −LogKMeas(sec)(sec)(mL)(mL)(cm)(cm)QLh1h0/h1ho/h1cm/s1047.3320.060.955.031.540.97.923.51.750.242.822051.0519.059.455.532.040.47.923.51.730.242.553050.8017.460.156.531.542.77.925.01.790.253.064050.6918.360.256.131.441.97.924.71.790.252.955046.6319.360.055.431.540.77.923.91.760.252.946046.3019.560.455.231.340.97.923.91.760.252.997046.3519.160.155.431.541.07.923.91.760.252.988046.8320.060.155.031.540.17.923.51.750.242.809048.9219.260.455.431.341.27.924.11.770.252.8910048.6118.860.555.631.341.77.924.31.780.252.9911049.4418.860.455.631.341.67.924.31.780.252.9312049.1419.860.655.131.140.87.924.01.770.252.8413047.9718.560.255.931.441.77.924.51.780.253.0614047.1519.560.955.131.541.47.923.61.750.242.8915046.9419.759.955.331.640.27.923.71.750.242.8316047.9119.160.255.431.441.17.924.01.760.252.9117048.8418.260.156.131.541.97.924.61.780.253.0418047.3320.060.355.031.440.37.923.61.750.242.8119047.5919.661.055.330.941.47.924.41.790.253.0820048.4719.760.455.331.340.77.924.01.770.252.8621047.7920.160.354.931.440.27.923.51.750.242.7522047.7119.660.255.331.440.67.923.91.760.252.8723047.2919.759.955.331.640.27.923.71.750.242.8124048.4420.260.254.931.440.07.923.51.750.242.7025049.5919.860.455.131.340.67.923.81.760.252.7526048.5219.660.255.331.440.67.923.91.760.252.8227049.5819.860.655.131.140.87.924.01.770.252.8228048.9419.660.255.331.440.67.923.91.760.252.8029049.3619.660.255.331.440.67.923.91.760.252.7730052.4019.460.455.431.341.07.924.11.770.252.6831052.0119.360.355.431.441.07.924.01.760.252.6832051.7419.860.255.131.440.47.923.71.750.242.5933051.8819.660.455.331.340.87.924.01.770.252.6834047.8219.560.255.431.440.77.924.01.760.252.8935048.2620.060.655.031.140.67.923.91.770.252.8636049.6319.460.155.431.540.77.923.91.760.252.7637049.4720.259.854.931.639.67.923.31.740.242.5738050.1120.260.754.931.140.57.923.81.770.252.7339048.6619.760.755.331.141.07.924.21.780.252.9340049.8420.261.054.930.940.87.924.01.780.252.8241033.1020.061.055.030.941.07.924.11.780.254.2942032.1420.060.055.031.540.07.923.51.750.244.0643032.5220.060.255.031.440.27.923.61.750.244.0844033.2520.061.855.032.441.87.922.61.700.233.7545032.5619.560.055.231.540.57.923.71.750.244.1246033.0319.460.255.431.440.87.924.01.760.254.2047032.8219.460.255.431.440.87.924.01.760.254.2248032.3219.659.955.331.540.37.923.81.760.244.1649032.4719.860.055.131.540.27.923.61.750.244.0750032.4119.660.255.331.440.67.923.91.760.254.2351032.6119.860.155.131.540.37.923.61.750.244.0752032.7520.060.455.031.340.47.923.71.760.244.1153032.5420.060.455.031.340.47.923.71.760.244.1454032.7519.860.455.131.340.67.923.81.760.254.1655032.4719.660.055.331.540.47.923.81.760.244.1656032.3819.560.255.431.440.77.924.01.760.254.2757032.6420.060.255.031.440.27.923.61.750.244.0658032.7120.060.455.031.340.47.923.71.760.244.1159032.9719.360.455.431.341.17.924.11.770.254.2860032.3319.960.255.131.440.37.923.71.750.244.1461032.9419.660.055.331.540.47.923.81.760.244.1062033.2219.360.055.431.540.77.923.91.760.254.1263033.0220.060.655.031.140.67.923.91.770.254.1864033.3119.660.255.331.440.67.923.91.760.254.1165033.1419.460.055.431.540.67.923.91.760.254.1266032.8020.060.255.031.440.27.923.61.750.244.0467032.8419.660.055.331.540.47.923.81.760.244.1168033.3419.660.255.331.440.67.923.91.760.254.1169032.1620.059.855.031.639.87.923.41.740.244.0070033.1419.860.455.131.340.67.923.81.760.254.1171033.3820.060.255.031.440.27.923.61.750.243.9772032.5920.060.155.031.540.17.923.51.750.244.0273033.1119.460.355.431.440.97.924.01.760.254.2074033.3120.060.355.031.440.37.923.61.750.243.9975033.0419.860.355.131.440.57.923.71.750.244.0776032.9820.060.255.031.440.27.923.61.750.244.0277033.4619.860.255.131.440.47.923.71.750.244.0178033.4319.460.055.431.540.67.923.91.760.254.0979032.8020.060.255.031.440.27.923.61.750.244.0480032.9020.060.455.031.340.47.923.71.760.244.09 TABLE 9 shows the results of RVM 420 tests conducted on palygorskite-rich media. The column height is 7.9 cm. The equation used is:K=QL/13.76t(h0−h1)×log 10(h0/h1) (1).M stands for the measurement number. T0 stands for Time0. T1 stands for Time1. Vol0 stands for Volume0. Vol1 stands for Volume1. TABLE 10Summary of Table 9 ResultsAveragecm/s3.47Minimumcm/s2.55Maximumcm/s4.29Variance0.42Standard Deviation0.65 TABLE 10 shows the summary of results from TABLE 9. Data for fine palygorskite granulated at <1.18 mm are listed in TABLE 11. Here, the RVM 420 tests were conducted with a column height at 7.9 cm. The equation used is:K=QL/13.76t(h0−h1)×log 10(h0/h1) (2).M stands for the measurement number. T0 stands for Time0. T1 stands for Time1. Vol0 stands for Volume0. Vol1 stands for Volume1. TABLE 11Permeability Tests of Fine DataT0T1Vol0Vol1Height0Height1h0 −LogKM(sec)(sec)(mL)(mL)(cm)(cm)QLh1h0/h1ho/h1cm/s1015.602.831.367.450.928.57.916.51.3241650.1219422.112017.5431.353.250.938.121.97.912.81.3359580.1257931.153014.909.031.064.050.722.07.913.31.2623270.1011721.144034.0031.069.550.728.938.57.921.81.7543250.244113.465026.1416.451.759.739.135.37.920.61.5268540.1837982.946033.2051.779.639.122.827.97.916.31.7149120.2342421.847013.690.623.968.955.723.37.913.21.2369840.0923641.198014.454.828.066.452.823.27.913.61.2575760.0995341.259019.4528.052.252.838.524.27.914.31.3714290.1371731.4010030.4252.278.538.523.226.37.915.31.6594830.2199731.6711013.753.325.967.554.122.67.913.41.2476890.0961071.2212021.7425.953.354.137.827.47.916.31.4312170.1557051.8413031.2853.379.637.822.826.37.915.01.6578950.2195571.5914013.472.325.067.754.822.77.912.91.2354010.0918081.1515019.7125.050.354.839.825.37.915.01.3768840.1388971.5416030.8550.377.039.824.326.77.915.51.6378600.2142771.6517015.865.831.165.751.125.37.914.61.2857140.1091441.4618024.8631.160.451.134.229.37.916.91.4941520.1743951.9919027.835.935.165.847.529.27.918.31.3852630.1415321.5620029.2035.168.247.529.533.17.918.01.6101690.2068722.42 TABLE 12Summary of Table 11 ResultsAverage1.73Minimum1.14Maximum3.46Variance0.38Standard Deviation0.62 Results from conducted RVM test #s 1-4 can be seen in TABLES 13-16. The column height for each of these 4 tests is 7.9 cm. TABLE 13RVM Test #1Measure-Time0Time1Volume0Volume1Height0Height1ment(sec)(sec)(mL)(mL)(cm)(cm)1047.3320.060.955.031.52051.0519.059.455.532.03050.8017.460.156.531.54050.6918.360.256.131.45046.6319.360.055.431.56046.3019.560.455.231.37046.3519.160.155.431.58046.8320.060.155.031.59048.9219.260.455.431.310048.6118.860.555.631.311049.4418.860.455.631.312049.1419.860.655.131.113047.9718.560.255.931.414047.1519.560.955.131.515046.9419.759.955.331.616047.9119.160.255.431.417048.8418.260.156.131.518047.3320.060.355.031.419047.5919.661.055.330.920048.4719.760.455.331.3 TABLE 14RVM Test #2Measure-Time0Time1Volume0Volume1Height0Height1ment(sec)(sec)(mL)(mL)(cm)(cm)1047.7920.160.354.931.42047.7119.660.255.331.43047.2919.759.955.331.64048.4420.260.254.931.45049.5919.860.455.131.36048.5219.660.255.331.47049.5819.860.655.131.18048.9419.660.255.331.49049.3619.660.255.331.410052.4019.460.455.431.311052.0119.360.355.431.412051.7419.860.255.131.413051.8819.660.455.331.314047.8219.560.255.431.415048.2620.060.655.031.116049.6319.460.155.431.517049.4720.259.854.931.618050.1120.260.754.931.119048.6619.760.755.331.120049.8420.261.054.930.9 TABLE 15RVM Test #3Measure-Time0Time1Volume0Volume1Height0Height1ment(sec)(sec)(mL)(mL)(cm)(cm)1033.1020.061.055.030.92032.1420.060.055.031.53032.5220.060.255.031.44033.2520.061.855.032.45032.5619.560.055.231.56033.0319.460.255.431.47032.8219.460.255.431.48032.3219.659.955.331.59032.4719.860.055.131.510032.4119.660.255.331.411032.6119.860.155.131.512032.7520.060.455.031.313032.5420.060.455.031.314032.7519.860.455.131.315032.4719.660.055.331.516032.3819.560.255.431.417032.6420.060.255.031.418032.7120.060.455.031.319032.9719.360.455.431.320032.3319.960.255.131.4 TABLE 16RVM Test #4Measure-Time0Time1Volume0Volume1Height0Height1ment(sec)(sec)(mL)(mL)(cm)(cm)1032.9419.660.055.331.52033.2219.360.055.431.53033.0220.060.655.031.14033.3119.660.255.331.45033.1419.460.055.431.56032.8020.060.255.031.47032.8419.660.055.331.58033.3419.660.255.331.49032.1620.059.855.031.610033.1419.860.455.131.311033.3820.060.255.031.412032.5920.060.155.031.513033.1119.460.355.431.414033.3120.060.355.031.415033.0419.860.355.131.416032.9820.060.255.031.417033.4619.860.255.131.418033.4319.460.055.431.519032.8020.060.255.031.420032.9020.060.455.031.3 Referring to FIG. 22, powder X-ray diffraction patterns for palygorskite-rich media used in the technology are shown for the range of 5-75° 2θ. The most intense peak of palygorskite is the (011) and is labeled in each pattern. There is some variation in the intensity, width and overall shape of the (011) palygorskite peak and this is interpreted to be a function of variation in width and chemical composition. Quartz is a common impurity and the most intense peak is labeled as well. EDS chemical composition data for unreacted palygorskite fibers (weight percent of oxides for each experimental run) are provided in TABLE 17. The minimum, maximum, median, variance and standard deviation of the elements are presented in TABLE 18. TABLE 17EDS data for unreacted palygorskite fibersAnaly-sisSiO2Al2O3Fe2O3MgOCaONa2OK2OTotal164.9212.0112.897.971.170.500.54100.00268.909.6912.158.230.760.000.28100.01362.1911.9512.489.252.790.780.5599.99462.8017.378.137.482.070.581.58100.01559.7218.046.719.282.592.651.01100.00663.0712.7310.5211.421.070.630.56100.00765.5711.3312.129.850.450.000.68100.00863.8712.467.658.026.830.770.3999.99964.4312.6712.228.611.010.560.50100.001066.2010.5012.898.031.410.320.6499.991163.7112.816.629.625.461.060.7199.991269.268.7111.528.950.320.690.57100.021364.859.4410.7113.260.670.820.26100.011467.6210.7210.989.800.600.150.1299.991562.2612.0810.5013.011.020.880.26100.011662.4011.5511.1710.922.030.641.30100.011763.9312.839.8411.510.570.670.66100.011876.198.555.059.970.200.020.0199.991975.908.205.309.610.310.560.1199.992074.3510.224.509.370.670.500.40100.012168.858.8910.9110.460.500.200.19100.002272.9011.375.049.720.490.420.06100.002366.6510.0910.9310.710.890.370.3599.992469.5510.499.399.060.910.320.28100.002578.536.933.829.350.560.730.0799.992680.066.913.608.360.550.310.21100.002777.408.584.398.890.480.000.26100.002874.759.643.8910.470.350.710.19100.002971.2315.494.447.510.330.250.76100.013070.1814.564.639.220.620.300.50100.013168.6217.624.436.980.640.561.16100.013267.7011.3611.498.220.870.040.32100.003365.7019.546.264.453.050.330.67100.003468.0517.396.165.471.170.681.08100.003563.9119.546.235.724.090.130.39100.013670.3616.794.447.330.480.120.4799.993770.2613.354.8010.200.550.540.2999.993871.3212.284.0911.270.290.240.52100.013973.5711.033.3710.320.680.660.37100.004072.3114.923.977.770.760.000.28100.014172.9913.494.368.130.590.020.4199.994273.729.914.0511.470.480.000.37100.004368.2211.2610.518.900.920.100.09100.004472.7212.553.3011.360.040.000.04100.014574.4411.033.649.730.690.120.3499.994673.6910.424.4210.980.480.000.02100.014772.0113.285.097.710.870.530.51100.004872.0614.114.288.480.460.090.5199.994973.2611.813.939.870.290.790.05100.005076.498.103.1510.620.860.300.48100.005174.1912.172.4310.130.760.000.3199.995273.5013.353.129.330.430.130.1399.995368.4213.984.7210.340.760.820.97100.015464.3922.104.336.790.900.810.6699.985571.2413.674.539.460.780.000.33100.015670.2812.164.2810.701.280.730.57100.005775.0612.574.087.610.470.000.21100.005875.0212.803.967.150.710.050.31100.005971.5715.544.396.790.940.320.4499.996075.029.384.295.813.681.410.42100.016168.1718.364.926.271.030.470.7799.996273.1613.166.765.760.790.000.38100.016378.438.794.297.170.840.000.48100.006466.4312.505.699.233.961.560.64100.016574.1912.154.258.100.510.460.3399.996670.1213.803.2311.730.360.450.32100.016771.5113.763.2610.590.480.200.1999.996867.5218.307.584.251.450.000.90100.006966.1719.736.395.820.780.650.4599.997073.1611.555.807.981.230.000.29100.017174.8011.704.218.500.780.000.0099.997274.0711.434.848.081.070.400.12100.017375.0610.325.207.981.140.250.05100.007467.9516.945.197.821.040.320.75100.017568.1711.838.6610.180.650.320.19100.007670.6010.729.418.000.960.000.3099.997770.758.6410.798.361.130.000.33100.007870.6011.098.927.491.750.000.15100.007969.0711.176.327.754.350.820.5199.998064.5816.208.196.982.100.381.5699.99 TABLE 18Summary of EDS data for unreacted palygorskite fibersSiO2Al2O3Fe2O3MgOCaONa2OK2OAverage70.0912.586.518.811.160.400.44Minimum59.726.912.434.250.040.000.00Maximum80.0622.1012.8913.266.832.651.58Variance20.2371210.020399.1677043.3206471.4383380.1820310.107066St. Dev.4.4985693.16553.0278221.8222641.1993070.4266510.32721 The following figures show plotted chemical compositions of individual, unreacted palygorskite particles. FIG. 23 shows a moderate linear relationship between Al2O3 and SiO2. However, FIGS. 24, 25 and 26 show no linear trends. FIG. 24 plots Fe2O3 and Al2O3 in a broadly triangular in shape. FIG. 25 shows MgO and Fe2O3 in a weak relationship, as does FIG. 26, which compares MgO and Al2O3. Illustrating images of unreacted palygorskite as the sorption based media, reference is made to FIGS. 27-30. FIG. 27 shows an SEM image of palygorskite rich clay used as an additional sorption media. The center portion of the image consists of a siliceous diatom fragment. Diatoms and similar microfossils are very common in the palygorskite-rich clay and add a minor amount to the overall sorption capacity. FIG. 28 shows an SEM image of palygorskite rich clay used as an additional sorption media. This image shows a platy mesoscale texture commonly observed in the palygorskite rich clay. Irregular shapes and clusters of fibers can be observed at the edge terminations of the platy particles. Minor pits and local micro topography of the samples can be seen in this image and the occurrence and distribution of these features adds to the reactive sorptive media. FIG. 29 shows an additional SEM image of palygorskite rich clay used as an additional sorption media. This image shows a platy mesoscale texture commonly observed in the palygorskite rich clay. Platy regions of sample material vary in average diameter form ˜0.5 μm to ˜15 μm. Edge terminations at this magnification appear to be irregular. Clusters of fibers can be observed at the edge terminations of the platy particle in the center. Minor pits can be observed in the low left of the image. Local microtopography of the sample material is clearly evident in this image. The occurrence and distribution of these features adds to the reactive sorptive media. FIG. 30 shows an SEM image of the upper edge termination of the central platy particle in the above image. Clusters of fibers protrude form the particle edge. The anastomosing or interlocking texture of palygorskite fibers is evident from a few examples in this image. Surface topography of particle is irregular and varied from particle to particle. Broad step like structures are observed in the fore ground and irregular “foil”-like textures are shown in the background. Palygorskite is reported to have a solubility product constant of 22.43 (Jones B. F. and Galán E., 19 Rev. in Mins. 631-674 (1988)). This constant suggests that the mineral is functionally insoluble over periods of years. For example, calcite and aragonite have solubility product constants of approximately 8.2-8.3 (Langmuir D, Aqueous Environmental Geochemistry, 1997) and are thus orders of magnitude more soluble than palygorskite. The palygorskite media is generally robust under water conditions as expected in radiological contamination. Palygorskite materials in the technology are broadly similar to those described by Krekeler et al., 53 Clays and Clay Mins. 94-101 (2005), Krekeler et al., 52 Clays and Clay Mins. 263-274 (2004), Krekeler 52 Clays and Clay Mins. 253-262 (2004) and Jones and Galán (1988). Palygorskite materials in the technology have somewhat less apatite, illite and oxide minerals. 2. Contact with Aqueous Slurry Once a radioactive containment composition contacts a radioactive material to form an aqueous slurry, floccules may be present. Such floccules may be removed using the sorption based media as a filtering mechanism. By accumulating floccules, the sorption based media may separate the floccules from the liquid. Separation may occur as a mechanical process. After the sorption based media contacts the aqueous slurry, a weight ratio of the sorption based media to aqueous slurry may range from 1:99 to 99:1. The following RVM 420 experimental results have been generated when the sorption based media is contacted with aqueous slurry. TABLE 19Experimental Permeability Test ResultsT0T1V0V1Hght0Hght1h0 −LogM(sec)(sec)(mL)(mL)(cm)(cm)QLh1h0/h1ho/h1K cm/s10168320.029.054.552.69.07.91.91.03610.0154110.00008991020163628.529.052.652.10.57.90.51.00960.0041480.00000036430981.30.40.769.068.70.37.90.31.00440.0018920.00000010040189237.039.247.646.82.27.90.81.01710.0073610.00000393150588313.018.067.359.015.07.98.31.14070.0571630.000069452 TABLE 19 shows RVM 420 experimental permeability test results. These results generally show how the palygorskite media slows down and accumulated floccules from a montmorillonite based aqueous slurry. The column height is 7.9 cm. The equation used is:K=QL/13.76t(h0−h1)×log 10(h0/h1) (1).M stands for the measurement number. T0 stands for Time0. T1 stands for Time1. Vol0 stands for Volume0. Vol1 stands for Volume1. Height0 stands for Height0. Hght1 stands for Height1. TABLE 20Summary of Experimental Permeability Test ResultsAverage0.000032751Minimum0.000000100Maximum0.000089910Variance0.000000002Standard Deviation0.000043473 TABLE 20 shows a summary of the results of the RVM 420 experimental permeability tests. The exemplified palygorskite-rich media may be used to accumulate floccules and additional cations in water or fluids with which the radionuclide containment composition having, for instance montmorillonite, interacts. In one example, hydraulic conductivity experiments using mixed SrCl2.6H2O and CsCl reacted montmorillonite waste formed visible floccules with sizes of ˜0.2-˜2 mm in average diameter. These sizes indicate that permeability tends to decrease orders of magnitude. Permeability coefficients may vary from ˜0.0000001 cm/s to ˜0.000089 cm/s compared to the observed range of ˜1.14 to ˜4.29 cm/sec for unmodified palygorskite-rich media using water. This variation indicates that the floccules are most likely being captured by the palygorskite sorption based media. The reduction in permeability is most likely the result of floccules clogging pore throats. TABLES 21 shows EDS chemical composition data (weight percent of oxides for each experimental run) for Sr reacted palygorskite fibers. The average, minimum, maximum, variance and standard deviation of the elements are presented in TABLE 22. TABLE 21EDS data for reacted Sr-palygorskite fibersAnalysisSiO2Al2O3Fe2O3MgOCaONa2OK2OSrOClTotal163.0815.895.305.900.470.060.178.880.25100.00258.9214.414.0310.440.000.900.227.900.1897.00362.9016.234.737.450.000.620.277.560.24100.00466.3013.493.857.950.170.140.307.570.23100.00563.6615.395.445.830.360.020.378.580.3499.99661.0815.504.539.480.000.650.178.480.12100.01765.896.824.0910.770.020.510.469.611.84100.01858.8110.583.8511.810.520.890.0610.862.62100.00960.4919.454.647.750.000.530.206.790.16100.011060.5118.604.297.760.050.600.337.570.29100.001159.3917.634.478.850.710.340.288.210.14100.021263.1212.483.6813.210.050.590.006.840.03100.001361.8517.324.208.630.160.480.167.060.15100.011461.5717.434.168.540.080.790.246.980.22100.011561.5216.944.897.670.000.560.437.830.17100.011664.507.033.0910.580.000.410.5511.442.3899.98 TABLE 22Summary of reacted Sr-exchanged palygorskite fibers EDS dataSiO2Al2O3Fe2O3MgOCaONa2OK2OSrOClAverage61.9415.214.418.800.170.510.248.050.47Minimum58.816.823.685.830.000.020.006.790.03Maximum66.3019.455.4413.210.710.900.4610.862.62Variance5.12910.870.27034.210.050.07401.2470.54St. Dev2.2653.2970.51992.050.230.2720.11.1170.74 TABLES 23 shows EDS chemical composition data (weight percent of oxides for each experimental run) for Sr reacted palygorskite fibers with Sr chloride mineralization. The average, minimum, maximum, variance and standard deviation of the elements are presented in TABLE 24. TABLE 23EDS data for Sr-exchanged palygorskite fibers with Sr chloridemineralizationAnalysisSiO2Al2O3Fe2O3MgOCaONa2OK2OSrOCl146.387.463.627.920.120.460.227.346.51241.726.842.955.620.390034.857.64338.97.722.285.670.0400.238.047.14446.083.381.999.13000.232.227.02560.448.233.318.590.210.58015.722.92637.345.962.576.10.0600.141.496.35744.135.43.637.090.350031.058.32 TABLE 24Summary of EDS data for Sr-exchanged palygorskite fibers with Srchloride mineralizationSiO2Al2O3Fe2O3MgOCaONa2OK2OSrOClAverage44.776.2552.78837.030.180.0970.132.236.57Minimum37.343.381.995.6200015.722.92Maximum60.448.233.639.130.390.580.241.498.32Variance69.333.0950.392.310.030.056080.073.62St. Dev8.3261.7590.62451.520.170.2370.18.9481.9 Illustrating Sr-exchange with the sorption based media, FIG. 31 shows a TEM image of a strontium chloride reacted sample showing interlocking palygorskite fibers. Fiber edges are straight and show no indication of dissolution. Widths are ˜15 nm to ˜40 nm. TABLES 25 shows EDS chemical composition data (weight percent of oxides for each experimental run) for Cs reacted palygorskite fibers. The average, minimum, maximum, variance and standard deviation of the elements are presented in TABLE 26. TABLE 25EDS data for Cs-exchanged palygorskite fibersAnalysisSiO2Al2O3Fe2O3MgOCaONa2OK2OCs2OTotal164.6910.095.668.982.580.000.167.86100.02264.428.666.7510.600.400.000.099.0799.99364.939.196.389.052.360.220.107.77100.00464.4410.776.519.272.750.000.156.11100.00564.1113.676.387.060.130.000.248.4099.99667.2712.536.926.070.080.000.107.0299.99756.1117.526.466.990.952.581.058.34100.00859.0816.097.366.920.900.241.208.2099.99960.6713.898.987.390.180.021.906.97100.001057.1815.358.079.360.112.291.486.16100.001160.7013.849.087.670.160.161.826.57100.001260.2315.918.897.560.090.001.805.52100.001354.2214.4810.046.994.390.232.726.93100.001454.8216.3410.717.310.250.283.307.00100.011564.6915.504.755.610.160.420.278.5999.991666.8513.114.685.460.000.500.329.0799.991764.2515.335.325.120.140.000.359.49100.001866.3215.854.464.400.090.000.008.88100.001966.7412.075.615.930.100.310.418.8299.992067.0712.805.236.020.050.160.108.57100.002166.0413.495.295.421.990.010.177.59100.002267.2214.504.455.410.880.050.187.3099.992366.3216.094.326.840.200.420.025.7899.992465.6415.665.005.100.110.170.417.8999.982566.0615.094.844.870.020.080.308.7399.992663.7418.294.793.920.100.241.287.64100.002762.6818.214.743.900.170.321.278.71100.002861.2419.244.634.750.070.000.929.16100.012963.6915.244.815.410.960.000.849.05100.003065.0714.584.665.541.180.000.698.28100.003162.7018.774.974.050.000.001.008.51100.003262.6219.684.804.460.000.431.666.35100.003366.3411.335.458.220.110.440.357.7599.993465.5413.415.668.270.000.160.356.61100.003563.9310.265.869.111.661.260.277.66100.013663.4311.866.038.521.470.290.417.99100.003763.5714.495.617.531.480.560.506.26100.003864.4317.385.776.430.710.480.734.07100.003865.9214.165.756.830.710.000.516.1199.994063.6413.536.819.290.810.310.185.44100.01 TABLE 26Summary of EDS data for Cs-exchanged palygorskite fibersSiO2Al2O3Fe2O3MgOCaONa2OK2OCs2OAverage63.4114.726.056.530.670.330.777.51Minimum54.229.194.323.900.000.000.004.07Maximum67.2719.6810.719.364.392.583.309.49Variance11.67496.06922.69772.64720.89560.31360.59481.5931St. Dev.3.416862.46361.64251.6270.94630.560.77121.2622 FIG. 32 illustrates TEM images of Cs-exchange with the sorption based media. A shows a TEM image showing palygorskite fibers that have been reacted with CsCl. Fibers are ˜10 nm to ˜25 nm in width. B shows a TEM image where palygorskite fibers have been reacted with CsCl. It may be noted that this images shows grain of quartz impurity. Fibers are commonly ˜20-˜50 nm in width. C shows a TEM image with aggregates of palygorskite fibers having been reacted with CsCl. Terminations of fibers are commonly straight. The larger fiber is approximately 100 nm in width. It appears that the fibers are not corroded and are essentially the same texture as unreacted fibers. In addition to these data and figures, the mixture of the sorption based media and radioactive containment composition can be seen in FIGS. 33 and 34. Each of these figures identify the differences in fiber size for the sorption based media and radioactive containment composition. As an example, the sorption based media is palygorskite and the radioactive containment composition involves montmorillonite. Referring to FIG. 33, A shows a TEM image from a grain mount with palygorskite fibers having widths ranging from ˜10 nm to ˜60 nm. Particles are inter-grown and form aggregates similar to those described in Krekeler et al. 2005. B shows a TEM image with a mixture of montmorillonite and palygorskite fibers. Montmorillonite occurs in the palygorskite source materials. Palygorskite fibers are ˜8 nm to ˜25 nm in width. The montmorillonite particle is ˜25 nm thick and ˜150 nm in length. C shows a TEM image with palygorskite fibers varying in width from ˜9 nm to ˜30 nm. It appears that there are straight and irregular terminations of the fibers along [100]. D shows a TEM image with palygorskite fibers that are ˜5 nm to ˜32 nm in width. A small montmorillonite particle is labeled and is ˜3 nm thick and ˜40 nm in length. Similarly, referring to FIG. 34, A shows a TEM image of a grain mount showing palygorskite fibers with widths from ˜15 nm to ˜30 nm. B shows a TEM image showing a mixture of palygorskite fibers ranging from ˜20 nm to ˜30 nm in width. C shows a TEM image with palygorskite fibers varying in width from ˜10 nm to ˜70 nm. It appears that there are straight and irregular terminations of the fibers along [100]. D shows a TEM image with palygorskite fibers that are ˜12 nm to ˜40 nm in width. A small montmorillonite particle is labeled and is ˜30 nm thick and ˜100+ nm in length. E. Relevance of pH Values The pH values of solutions and suspensions are critical data for understanding the mechanisms of the chemistry of the solutions and suspensions. The range of pH values observed in the reacted material serves as a function of the degree of reaction that has taken place. Below are described pH data from bulk experiments. For example, NO3− from a 0.05 N AgNO3 solution is not precipitated in any phase and is ambient in the solution. Accordingly, NO3− equilibrates to HNO3, giving rise to more acid conditions in reacted supernatant fluids. As shown in TABLE 27, the following pH values were obtained for the montmorillonite used in the experiments. The montmorillonite here has not yet been applied to a chloride containing substance or treated with AgNO3 (aq). TABLE 27pH Values of Montmorillonite SuspensionsAnalysis #pHmVTemperature (° C.)19.15−141.818.629.13−140.118.139.19−143.918.748.59−108.518.659.10−139.418.569.25−147.618.479.26−148.318.789.29−150.418.599.30−151.918.6109.33−152.718.5119.21−145.918.4129.30−150.718.8 In addition to the data above, the pH of Na-montmorillonite was measured in forty other different analyses. The pH values of several preparations of the aqueous clay suspension 115 were measured directly using an accumet XL 15 pH meter. Each measurement took between 10 and 20 minutes to stabilize. The pH value gradually would climb from approximately 7 to final numbers obtained. A stable value was considered to be one that did not fluctuate for 3 minutes. Three measurements were made for each analysis. For each weight percent solid determination, the product was placed in aluminum dishes and heated at 120° C. for a minimum of 24 hours. The pH values varied from 8.60 to 9.42 with 9.21 being the average. The standard deviation is 0.19. Weight percent solids varied from 2.60 to 13.99 with 5.33 being the average. The standard deviation is 4.28. The data is shown in TABLES 28-29. Although the pH is elevated with respect to environmental waters, it is still comparatively low compared to many bases, and therefore is safe for building materials to which it would be applied. The pH range is also acceptable for short term human exposure. TABLE 28pH and mV of Na-montmorillonitepHTrialTrialmVAnalysis1Trial 23AverageTrial 1Trial 2Trial 3 19.249.359.349.31−146.1−151.3−151.3 29.319.259.299.28−149.3−146.4−148.6 39.319.349.349.33−150.0−151.2−151.1 49.359.339.339.34−151.4−150.1−150.5 59.409.399.399.39−154.9−154.2−153.6 69.429.369.369.38−156.5−152.5−152.9 79.379.349.349.35−152.7−151.6−150.8 89.329.299.289.30−149.9−148.5−147.9 99.389.359.319.35−154.0−152.2−149.9109.359.349.299.33−151.8−151.7−148.5119.319.269.289.28−149.4−146.5−147.9128.698.778.818.76−113.5−118.1−120.1139.049.059.079.05−133.8−134.3−135.6149.209.159.159.17−143.3−140.4−140.4159.179.129.129.14−141.9−138.8−138.6169.159.139.119.13−140.1−139.0−137.8179.219.199.199.20−143.9−142.7−142.6188.618.888.848.78−108.6−124.6−122.6199.129.079.129.10−139.4−135.8−139.2209.279.229.239.24−147.6−145.0−145.8219.289.319.319.30−148.2−150.2−150.1229.319.309.309.30−150.4−149.4−149.4239.329.329.309.31−150.9−151.0−149.8249.359.369.319.34−152.7−153.4−150.4259.239.259.329.27−145.9−146.8−150.9269.329.319.299.31−150.7−150.2−149.4278.608.808.678.69−108.4−120.4−112.2289.089.089.159.10−136.5−136.8−141.2299.099.059.029.05−137.3−134.9−133.3309.209.199.209.20−143.7−143.3−143.6319.329.349.329.33−151.2−152.4−151.1329.429.409.389.40−157.2−156.6−154.8339.319.349.149.26−151.1−153.2−141.9349.339.399.369.36−153.3−156.9−154.9359.239.279.309.27−147.2−149.5−151.5369.379.399.419.39−155.4−156.8−158.0379.409.449.449.43−157.7−159.6−159.6388.878.898.908.89−126.1−126.1−127.6398.908.928.968.93−127.7−127.7−130.4408.938.938.958.94−128.7−128.7−130.1Average9.209.219.219.21−144.0−144.5−144.1Maximum9.429.449.449.43−108.4−118.1−112.2Minimum8.608.778.678.69−157.7−159.6−159.6Std. Dev.0.191 TABLE 29Temp (° C.) and Weight % Solid of Na-montmorillonitefor the Respective pH and mV Values in Table 12Temp (C.)AnalysisTrial 1Trial 2Trial 3% solid118.015.917.12.94217.117.317.32.89317.217.116.43.00416.315.516.92.97517.217.217.12.98617.617.517.32.96716.717.216.32.94817.116.817.22.95917.817.417.63.011017.317.617.13.051117.016.917.22.991218.217.817.02.871317.717.417.82.981417.918.018.12.991518.017.918.03.041617.117.217.63.091717.517.517.52.771818.918.718.82.601918.618.618.72.672018.418.518.62.682118.218.618.62.772218.118.117.92.722318.418.418.52.692418.718.518.62.732518.718.419.02.722618.618.818.62.752718.918.718.82.922818.518.518.83.082918.818.819.03.003018.518.618.63.103119.419.419.412.323219.819.819.711.703320.120.620.613.383421.821.621.610.903521.721.521.512.763621.321.521.513.083721.621.621.713.993820.720.720.712.433920.420.420.413.044020.720.420.412.62Average5.33Maximum13.99Minimum2.60Std. Dev.4.288 In this set of experiments, pH values were obtained for the 0.05 N AgNO3 solution. The observed pH values varied from about 3.22 to about 4.6. As shown in TABLE 30, these values tend to range low because the base pair for Ag+, AgOH is much weaker than the acid HNO3. The 4.6 reading was obtained after the solution may be a result of allowing the solution to sit overnight, equilibrate with atmospheric CO2, and/or be a product from light. However, this higher value indicates how the solution can intrinsically behave in open air. TABLE 30Representative pH Values of 0.05 NAgNO3 Solution Used in ExperimentsAnalysis #pHmVTemperature (° C.)13.22199.52323.28197.22334.6156.61843.55185.02153.25198.522 In this set of experiments, chloride powders (i.e., CsCl, SrCl2.6H2O and BaCl2) were reacted with the montmorillonite technology and were then mixed with variable amounts of 0.05 N AgNO3 solution. The AgNO3 solution had approximately between 150 ml and 10 ml per 0.014 mol cation equivalent. Specifically, 2.5 g of equivalent Cs cation, 3.082 g of equivalent Ba cation and 3.944 g of equivalent Sr cation were used. Each of these piles was sprayed 20 times with a slurry of Na-montmorillonite. Thereafter, each pile was removed and placed into a beaker. The beaker was then filled with more Na-montmorillonite slurry until there was 100 ml of combined substance. Approximately 50 ml of de-ionized water may be added to each beaker to aid dissolution of each respective salt. An additional 50 ml was added to ach beaker for a total of 200 ml of mixture. To these mixtures, a volume of 10 ml, 50 ml, 100 ml, and 150 ml of 0.05 N AgNO3. The pH data from replicate measurements from the resulting mixtures ranged from about 6.76 to 7.61, as shown in TABLE 31. This range indicates that the waste is not corrosive and could be stored in a variety of containers. Examples of containers include, but are not limited to, stainless steel, plastic lined drums, metal drums, or other storage tanks made of polymers, metals or a combination of materials. TABLE 31pH values of Mixed WasteAnalysis #pHmVTemperature (° C.)16.76−3.523.526.97−7.823.637.14−17.523.647.10−15.223.357.20−21.623.667.34−29.923.677.28−25.923.687.55−41.723.397.60−45.223.6107.61−45.423.4117.31−27.523.6127.41−33.723.6137.39−32.323.4147.47−37.423.4157.52−39.323.4Average7.31−28.2623.50Minimum6.76−45.4023.30Maximum7.61−3.5023.60 For the same experiment above, supernatant solutions were also obtained. The pH data from replicate measurements from the resulting solutions separated from the water mixture are provided below. The pH values are between approximately 6.9 and approximately 7.53, as shown in TABLE 32. As above, this range indicates (and perhaps reaffirms) that the waste is not corrosive and could be stored in a variety of containers. Again, nonlimiting examples of containers include: stainless steel, plastic lined drums, metal drums, or other storage tanks made of polymers, metals or a combination of materials. TABLE 32Representative pH Values of Supernatant Solution from Experimentswhere Waste from CsCl, BaCl2 and SrCl2•6H2O were MixedAnalysis #pHmVTemperature (° C.)17.38−31.923.827.53−40.823.437.34−29.323.747.5−3923.856.9−16.323.766.94−17.323.876.98−19.323.787.02−2323.897.05−23.523.7107.08−27.923.8 Below demonstrates an example of a pure end member reaction. Here, 100 ml of 0.05 N AgNO3 solution was reacted with 100 ml of 0.25 M Cl. The solution immediately turned white as expected. As shown in TABLE 33, the pH values for the resulting solution varied from about 6.47 to about 6.96. This near neutral pH range occurs because the acid-base pairs for Ag+, Cs, Cl− and NO3− are of similar strength with HNO3, making a slightly stronger acid in the system than equilibration of the base CsOH. Also, this range indicates that the waste is stable for storage in the same or similar manner as described above, where a variety of containers may be used. TABLE 33pH Values of Resulting Suspension from theReaction of 100 ml of 0.05 N AgNO3 solutionwas reacted with 100 ml of 0.25 M Cl solution.Analysis #pHmVTemperature (° C.)16.47−10.923.126.92−13.923.137−18.923.246.96−18.223.156.88−13.323.266.74−5.523.276.74−5.223.286.71−3.423.296.47−11.123.4106.5−9.123.1116.52−7.723.1 F. Proving the Exchange of Cs+ Transmission electron microscopy investigation of the aqueous clay suspension 115 indicates that the material does indeed exchange with Cs and sequesters the cation. The crystallinity of the montmorillonite generally increases with the exchange of Cs into the structure. SAED data show that diffraction along (hk0) in Na-montmorillonite particles is heavily streaked as expected from the turbostratic stacking. However, the Cs-exchanged montmorillonite shows discrete spots along (hk0) in a pseudohexagonal net indicating a higher degree of crystallinity. The overall morphology of the particles does not appear to change significantly. The foregoing descriptions of the embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or be limiting to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The illustrated embodiments were chosen and described in order to best explain the principles of the present invention and its practical application to thereby enable others skilled in the art to best utilize it in various embodiments and with various modifications as are suited to the particular use contemplated without departing from the spirit and scope of the present invention. In fact, after reading the above description, it will be apparent to one skilled in the relevant art(s) how to implement the present invention in alternative embodiments. Thus, the present invention should not be limited by any of the above described example embodiments. For example, the present invention may be practiced over water treatment plants, environmental and/or biohazardous spills, etc. Further, the present invention may be used for containing chemical and/or biological weapons (e.g., anthrax, small pox, etc.). In addition, it should be understood that any figures, graphs, tables, examples, etc., which highlight the functionality and advantages of the present invention, are presented for example purposes only. The architecture of the disclosed is sufficiently flexible and configurable, such that it may be utilized in ways other than that shown. For example, the steps listed in any flowchart may be reordered or only optionally used in some embodiments. Further, the purpose of the Abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the present invention of the application. The Abstract is not intended to be limiting as to the scope of the present invention in any way. Furthermore, it is the applicants' intent that only claims that include the express language “means for” or “step for” be interpreted under 35 U.S.C. §112, paragraph 6. Claims that do not expressly include the phrase “means for” or “step for” are not to be interpreted under 35 U.S.C. §112, paragraph 6. A portion of the present invention of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent invention, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. |
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abstract | This invention extends the Kirkpatrick-Baez (KB) mirror focusing geometry to allow nondispersive focusing of neutrons with a convergence on a sample much larger than is possible with existing KB optical schemes by establishing an array of at least three mirrors and focusing neutrons by appropriate multiple deflections via the array. The method may be utilized with supermirrors, multilayer mirrors, or total external reflection mirrors. Because high-energy x-rays behave like neutrons in their absorption and reflectivity rates, this method may be used with x-rays as well as neutrons. |
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claims | 1. An electrochemical corrosion potential sensor comprising:a conductive electrode fixing body;an electrode cap member made of zirconium and fixed to the electrode fixing body;a tubular insulator connected to the electrode fixing body;a tubular metallic housing connected to the tubular insulator; anda conductive wire passing through the tubular insulator and the tubular metallic housing and connected to the electrode fixing body;wherein in a first connecting portion of the electrode fixing body and one end portion of the tubular insulator, the electrode fixing body is disposed outside of the tubular insulator and overlapped to the tubular insulator;wherein in a second connecting portion of another end portion of the tubular insulator and the tubular metallic housing, the tubular metallic housing is disposed outside of the tubular insulator and overlapped to the tubular insulator;wherein the electrode cap member is disposed to cover an outer surface of the electrode fixing body;wherein the electrode cap member is disposed to cover the outer surface of the electrode fixing body and an outer surface of the first connecting portion; andwherein a metallic spacer made of zirconium is disposed in a clearance between the electrode cap member and the tubular insulator. 2. The electrochemical corrosion potential sensor according to claim 1, wherein the electrode cap member and the metallic spacer are fixed to each other by welding. 3. The electrochemical corrosion potential sensor according to claim 1, wherein an outer surface of the second connecting portion is covered with an interlayer; and a surface of the interlayer is covered with platinum. 4. The electrochemical corrosion potential sensor according to claim 3, wherein the interlayer is composed of titanium. 5. The electrochemical corrosion potential sensor according to claim 1, wherein a coefficient of linear expansion of each of the electrode fixing body and the tubular metallic housing is smaller than a coefficient of linear expansion of the tubular insulator. 6. The electrochemical corrosion potential sensor according to claim 5, wherein the electrode fixing body and the tubular metallic housing are made of Fe-29Ni-17Co alloy or Fe-42Ni alloy. 7. The electrochemical corrosion potential sensor according to claim 5, wherein the tubular insulator is sapphire or stabilized zirconia. 8. The electrochemical corrosion potential sensor according to claim 1, wherein a first metallization section is formed on an outer surface of the tubular insulator in the first connecting portion, and the first metallization section is connected with the electrode fixing body by metal. 9. The electrochemical corrosion potential sensor according to claim 1, wherein a second metallization section is formed on an outer surface of the tubular insulator in the second connecting portion, and the second metallization section is connected with the tubular metallic housing by metal. |
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summary | ||
claims | 1. Apparatus for producing radioactive iodine isotopes comprising:a neutron generator that is not a nuclear reactor;an irradiation chamber comprising a number of regions configured to receive NEU material to be fissioned upon irradiation by neutrons generated by the neutron generator, at least one non-moderating neutron-reflecting region, a gas inlet port, and a gas outlet port;wherein the gas inlet port, the gas outlet port, and the number of regions configured to receive NEU material are in gas communication; andwherein the at least one non-moderating neutron-reflecting region comprises one or more walls of the irradiation chamber formed of non-moderating neutron-reflecting material. 2. The apparatus of claim 1 wherein the neutron generator provides neutrons with an energy above a fast fission threshold for U-238. 3. The apparatus of claim 1 wherein the mechanism for separating at least some of the radioactive iodine comprises a silver zeolite trap. 4. The apparatus of claim 1, and wherein the at least one non-moderating neutron-reflecting region comprises at least one interior non-moderating neutron-reflecting region disposed within the irradiation chamber and further comprises one or more walls of the irradiation chamber; wherein the at least one non-moderating neutron-reflecting region is configured to increase the path length traveled by at least some of the neutrons before those neutrons leave the irradiation chamber. 5. The apparatus of claim 1 wherein the NEU material comprises depleted uranium material. 6. The apparatus of claim 1 wherein the NEU material comprises one of the following forms: solid material, crushed solid material, metallic shavings, metallic filings, sintered pellets, liquid solutions, molten salts, molten alloys, slurries, sheets, plates, rods, and granular material. 7. The apparatus of claim 1 wherein the irradiation chamber further comprises a fill port configured to allow the introduction of the NEU material and a drain port configured for removal of the NEU material. 8. The apparatus of claim 1 wherein the irradiation chamber comprises at least two sections. 9. Apparatus for producing radioactive iodine comprising:a compact, stand-alone neutron generator;an irradiation chamber, the irradiation chamber comprises at least one region configured to receive NEU material to be fissioned upon irradiation by neutrons generated by the neutron generator, at least one non-moderating neutron-reflecting region, a gas inlet, and a gas outlet;means for introducing a carrier gas into the gas inlet to form a gas mixture with a fission products;means for withdrawing the gas mixture from the gas outlet;means for separating at least a portion of the fission products from the gas mixture; andwherein the at least one non-moderating neutron-reflecting region comprises one or more walls of the irradiation chamber formed of non-moderating neutron-reflecting material. 10. The apparatus of claim 9 wherein the compact, stand-alone neutron generator provides neutrons with an energy above a fast fission threshold for U-238. 11. The apparatus of claim 9 wherein the means for separating at least a portion of the fission products comprises a silver zeolite trap. 12. The apparatus of claim 9 wherein the NEU material comprises one of the following forms: solid material, crushed solid material, metallic shavings, metallic filings, sintered pellets, liquid solutions, molten salts, molten alloys, slurries, sheets, plates, rods, and granular material. 13. The apparatus of claim 9 wherein the NEU material comprises depleted uranium material. 14. The apparatus of claim 9 wherein the irradiation chamber further comprises a fill port configured to allow the introduction of the NEU material and a drain port configured for removal of the NEU material. 15. The apparatus of claim 9 wherein the irradiation chamber comprises at least two sections. 16. The apparatus of claim 1 wherein the NEU material comprises NEU in the form of flat plates. 17. The apparatus of claim 1 wherein the irradiation chamber comprises a rectangular-prism-shaped irradiation chamber. 18. The apparatus of claim 9 wherein the NEU material comprises NEU in the form of flat plates. 19. The apparatus of claim 9 wherein the irradiation chamber comprises a rectangular-prism-shaped irradiation chamber. |
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056617690 | claims | 1. A depressurising system (1) for plants operating with pressurised steam and including a steam head (16), by injection of cold water under gravity from a reservoir (2) located at a position higher than the pressurised plant and having a delivery duct (24) for delivery to the pressurised plant, characterised in that it includes an ejector (6) which has an inlet section (8), an outlet section (9) and a narrow section (10), a condenser (7) which has an inlet (11) and an outlet (12), a first connector duct (18) which puts the reservoir (2) in communication with the steam head (16), a second connector duct (20) which puts the inlet section (8) of the ejector (6) in communication with the steam head (16), a third connector duct (21) which puts the outlet section (9) in communication with the inlet (11) of the condenser (7), a first injector duct (22) which puts the outlet (12) of the condenser (7) in communication with the pressurised plant, and in that the delivery duct (24) forms a syphon (24a, 24b, 24c), the reservoir (2) communicating with the pressurised plant through the delivery duct (24) and through the narrow section (10) of the ejector (6). 2. A depressurising system (1) according to claim 1, characterised in that the first injector duct (22) terminates in a spray head (23). 3. A depressurising system (1) according to claim 1, characterised in that it includes a second injector duct (25) which branches from the third connector duct (21) and opens into a pressure vessel (26) of the pressurised plant. 4. A depressurising system (1) according to claim 3, characterised in that the second injector duct terminates in a spray head (29) within the pressure vessel (26). 5. A depressurising system (1) according to claim 1, characterised in that it includes a third injector duct (27) which branches from the third connector duct (21) and which opens into the steam head (16) of the pressurised plant and in that the third injector duct (27) has a descending portion (27a), a lower portion (27b) and an ascending portion (27c). 6. A depressurising system (1) according to claim 5, characterised in that the third injector duct (27) terminates in a spray head (28) within the steam head (16) . |
050698605 | claims | 1. A rotary lock for preventing rotation of a shaft of a control rod drive comprising: a stationary housing for receiving said shaft; an arm having a proximal end fixedly joined to said shaft in said housing, a distal end extending radially outwardly from said shaft, a top surface, and a side surface; a pin having a proximal portion joined to said housing for circumferential restraint relative to said shaft, an intermediate portion, and a distal portion, said pin being positioned in a withdrawn position away from said arm top surface for allowing said arm to rotate with said shaft without obstruction from said pin, and in a deployed position for allowing said pin intermediate portion to contact said arm side surface at said arm distal end for preventing rotation of said arm and said shaft; and means for selectively positioning said pin in said withdrawn and deployed positions. means for urging said pin to one of said withdrawn and deployed positions; and an actuator energizable for moving said pin into the other of said withdrawn and deployed positions. said plunger is tubular and includes a central bore disposed coaxially about said shaft for longitudinal movement relative thereto, a base plate disposed at one end of said plunger adjacent to said arm, an intermediate portion extending from said base plate and through said solenoid, and a flange joined to said intermediate portion at an opposite end of said plunger; said plunger base plate includes a plurality of circumferentially spaced guide holes facing said arm, each of said guide holes including a pin tubular recess extending therefrom; a plurality of said pins extend from respective ones of said pin recesses through respective ones of said plunger guide holes toward said arm, each pin including a flange joined to said pin proximal portion disposed in said pin recess; a plurality of pin springs disposed in respective ones of said pin recesses for providing a spring force on said pin flange for urging said pin flange toward said guide hole for positioning said pin intermediate and distal portions outwardly from said plunger base plate toward said arm in an extended position for allowing said pin intermediate portion to contact said arm side surface in said deployed position, said pin recess having a longitudinal depth effective for allowing said pin to be urged into said recess against said spring in a retracted position when said pin distal portion contacts said arm top surface in said deployed position; and said plunger being positionable in said deployed and withdrawn positions for deploying and withdrawing said pins by de-energizing and energizing said solenoid. 2. A rotary lock according to claim 1 wherein said pin positioning means comprises: 3. A rotary lock according to claim 2 wherein said actuator is a solenoid. 4. A rotary lock according to claim 3 further including a plunger slideably disposed in said solenoid and joined to said pin for moving said pin when said solenoid is energized. 5. A rotary lock according to claim 4 wherein: 6. A rotary lock according to claim 5 wherein said urging means is a plunger compression spring disposed around said plunger intermediate portion and between said base plate and said solenoid for urging said plunger base plate including said plurality of pins toward said arm in said deployed position when said solenoid is de-energized, said solenoid being effective for disposing said plunger and said pins in said withdrawn position and compressing said plunger compression spring when said solenoid is energized. 7. A rotary lock according to claim 5 wherein said urging means comprises said shaft and said plunger being oriented vertically with said plunger being disposed above said shaft arm for allowing gravity to pull said plunger toward said arm in said deployed position when said solenoid is de-energized. 8. A rotary lock according to claim 5 wherein said plunger base plate includes a perimeter having at least one longitudinal guide recess therein, said housing includes a longitudinal guide rail fixedly joined to said housing and extending parallel to and into said guide recess for allowing said plunger to move longitudinally along said shaft between said deployed and withdrawn positions while circumferentially restraining said plunger and said pins from rotating about said shaft when at least one of said pins contacts said arm side surface in said deployed position. 9. A rotary lock according to claim 8 further including a restraint plate spaced from a bottom surface of said shaft arm and having a plurality of circumferentially spaced restraint holes longitudinally aligned with respective ones of said pins, said pins being sized for positioning said distal portions into said restraint holes when in said deployed position. 10. A rotary lock according to claim 9 wherein said guide recess and rail are positioned for longitudinally aligning respective pairs of said pins and said restraint holes. 11. A rotary lock according to claim 10 further comprising a pair of said arms including a first arm and a second arm having side surfaces for contacting respective ones of said pins in said deployed position. 12. A rotary lock according to claim 11 wherein said pins, restraint holes, and arms are configured so that at least one of said pair of arms is positioned between adjacent ones of said pins for allowing said distal portions of said adjacent ones of said pins to be positioned in respective restraint holes in said deployed position without obstruction by said at least one arm. 13. A rotary lock according to claim 12 wherein said pins and said restraint holes are equiangularly spaced from each other and said second arm is disposed obliquely to said first arm for allowing said adjacent pins to enter said respective restraint holes without obstruction by said at least one arm. 14. A rotary lock according to claim 4 further including a support plate fixedly joined to said housing for fixedly supporting said solenoid and wherein said plunger is fixedly joined to said pin proximal portion. 15. A rotary lock according to claim 14 wherein said plunger is tubular having a central bore and further including a solenoid compression spring disposed in said central bore and said solenoid for moving said pin to said deployed position when said solenoid is de-energized, said solenoid being effective for moving said pin to said withdrawn position when energized. 16. A rotary lock according to claim 15 further including a restraint plate spaced from a bottom surface of said shaft arm and having at least one restraint hole longitudinally aligned with said pin, said pin being sized for positioning said pin distal portion into said restraint hole when in said deployed position. 17. A rotary lock according to claim 16 further including two of said solenoids, plungers, solenoid compression springs, pins, and restraint holes. 18. A rotary lock according to claim 17 further comprising a pair of said arms including a first arm and a second arm having side surfaces for contacting respective ones of said pins in said deployed position. 19. A rotary lock according to claim 18 wherein said pins, restraint holes, and arms are configured so that at least one of said pair of arms is positioned between adjacent ones of said pins for allowing said distal portions of said adjacent ones of said pins to be positioned in respective restraint holes in said deployed position without obstruction by said at least one arm. 20. A rotary lock according to claim 19 wherein said pins and said restraint holes are equiangularly spaced from each other and said second arm is disposed obliquely to said first arm for allowing said adjacent pins to enter said respective restraint holes without obstruction by said at least one arm. |
claims | 1. A power monitoring system comprising:a plurality of local power range monitoring devices, each of the local power range monitoring devices having a plurality of local power channels to obtain local neutron distribution in a nuclear reactor core;an averaged power range monitoring device that receives power output signals from the plurality of the local power range monitoring devices and obtains an average output power signal of the reactor core as a whole; andan oscillation power range monitoring device including an oscillation power range monitoring mechanism that receives power output signals from the local power range monitoring devices and monitors power oscillations of the reactor core, whereinthe output signals from the local power range monitoring devices to the averaged power range monitoring device and the output signals from the local power range monitoring devices to the oscillation power range monitoring device are independent, whereineach of the local power range monitoring devices has a function to transmit to the oscillation power range monitoring device, breakdown or exclusion signals of the local power range monitoring device itself and of any of the local power channels connected to the local power range monitoring device,when the breakdown or exclusion signal of one or more of the local power channels is generated, the oscillation power range monitoring device excludes only the one or more local power channels corresponding to the breakdown or exclusion signal or signals,when the breakdown or exclusion signal of one or more of the local power range monitoring devices is generated, the oscillation power range monitoring device excludes all local power channels corresponding to the one or more local power range monitoring devices, andvariables that are changed according to a type of fuel of the reactor core are set by hardware switches on a board that comprises part of the oscillation power range monitoring mechanism, the hardware switches comprising a combination of electrical contacts that are positioned such that the variables cannot be changed without stopping the oscillation power range monitoring mechanism. 2. The power monitoring system according to claim 1, wherein,the variables that are changed according to the type of fuel of the reactor core are stored in an element whose internal state cannot be changed by operation of the oscillation power range monitoring mechanism. 3. The power monitoring system according to claim 1, whereinthe oscillation power range monitoring mechanism has a transmission section that transmits output signals not having input signals in a one-way direction, and the transmission section transmits the output signals to a state display section that displays state of power oscillations. 4. The power monitoring system according to claim 1, whereinthe oscillation power range monitoring mechanism has a transmission section that transmits output signals not having input signals in a one-way direction, and the transmission section transmits the output signals to a history recording device that records a predetermined period of time of past history. 5. The power monitoring system according to claim 4, whereinthe history recording device includes: a determination means that makes a determination as to whether data is normally received; and a determination result transmission means that transmits a determination result of the determination means to the transmission section, wherein transmission of data from another oscillation power range monitoring mechanism to the transmission section is limited to one-way transmission. 6. The power monitoring system according to claim 4, whereinthe transmission section and the history recording device are electrically isolated. 7. The power monitoring system according to claim 1, wherein at least one variable that is changed according to the type of fuel of the reactor core is selected from the group consisting of a peak determination amplitude value, a trough determination amplitude value, a multiplication factor determination value, a trip determination amplitude value, an oscillation interval minimum determination value, and an oscillation interval maximum determination value. |
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052251489 | description | DESCRIPTION OF PREFERRED EMBODIMENT As shown in FIG. 1, duplex tube can be seen designated in a general manner by the reference numeral 1 and comprises a tubular core 2 made from a zirconium alloy covered externally by a cladding layer 3 made from a second zirconium alloy, the composition of which differs from the composition of the alloy constituting the core 2. The zirconium alloys constituting the core 2 and the cladding layer 3 of the duplex tube 1 are low-alloy zirconium alloys in which the content of alloying elements is less than 1% by weight for each of these elements. The tubular core 2 and the cladding layer 3 therefore have acoustic properties which are extremely similar to each other. Furthermore, the covering or cladding layer 3 has a small thickness, generally lying between 60 and 80 .mu.m, the metallic core 2 itself having a thickness slightly less than 600 .mu.m. A duplex tube such as that shown in FIG. 1, used as a jacket for a fuel rod of a pressurized-water nuclear reactor assembly, generally has an external diameter of the order of 10 mm and a length of the order of 4 m. In FIG. 2A, the wall of a duplex tube such as that shown in FIG. 1 has been shown in section, comprising a tubular core 2 covered by a cladding and covering layer joined to the metallic core along a cylindrical interface surface 4. In order to measure the total thickness of the wall of the jacket consisting of the core 2 and the cladding layer 3, an ultrasonic transducer 5 is used which emits an ultrasonic-wave beam 6 in the direction of the outer surface of the duplex tube, consisting of the outer surface of the cladding layer 3. The tube 1 is immersed in a coupling medium consisting of a liquid permitting the transmission of the ultrasonic waves emitted by the transducer 5. Part of the ultrasonic-wave beam 6 is reflected by the outer surface of the duplex tube in the form of a beam 6' which is collected by the transducer 5 and converted into an electrical signal which is transmitted to a processing unit 7. The corresponding echo 8 can be displayed on an oscillogram giving an image of its amplitude and position against a time scale. The ultrasonic beam 6a transmitted through the wall of the duplex tube is reflected, in the form of a beam 6'a, by the inner surface of the core 2 of the duplex tube. The ultrasonic beam 6'a is collected by the transducer 5 which converts it into an electrical signal and enables it, by virtue of the processing module 7, to be displayed on the oscillogram in FIG. 2B in the form of an echo signal 8a. The time lag between the signal 8 and the signal 8a corresponds to twice the time .delta.T taken for the ultrasonic waves to travel through the wall of the tube 1. It is possible to obtain an approximate value for the total thickness e.sub.g of the jacket corresponding to the thickness of the wall of the duplex tube by assuming that the speeds of propagation of the ultrasonic waves in the metallic core of the jacket and in the cladding layer are identical. This method of determination is only approximate, inasfar as the speed of propagation V.sub.p of the longitudinal ultrasonic waves in the cladding material is not identical to the speed of propagation V.sub.a of the ultrasonic waves in the material constituting the core of the duplex tube. On the other hand, the method of measuring directly the propagation time of ultrasonic waves does not permit the measurement of the thickness of the cladding layer e.sub.p, the coefficient of reflection of the acoustic waves at the interface 4 between the cladding layer 3 and the core 2 being very small (generally less than 2%), because the acoustic properties of the materials constituting the cladding layer and the core are extremely similar to each other. Furthermore, the cladding layer has a small thickness as compared with the total thickness of the wall, with the result that the differences in the propagation times to be taken into account are themselves very small. In FIGS. 3A, 3B and 3C, three different embodiments of a Foucault-current device have been shown, permitting the measurement of the thickness of an outer cladding layer of a duplex tube 1 consisting of a metallic core covered with a cladding layer, the metallic core and the cladding layer consisting of two zirconium alloys containing very small quantities of alloying elements. Small variations in alloying measurements in low-alloy alloys can give rise to very considerable variations in the electrical conductivity of these alloys. For example, in the case of zircaloy, which is a zirconium alloy containing tin, a variation of 1% in the tin content gives rise to a variation in conductivity of the order of 50%. Such variations make it possible to apply the technique of induced currents or Foucault currents in order to check the thickness of a cladding layer whose composition differs from that of the metallic core covered by the cladding layer. It is possible to use, as shown in FIG. 3A, a coil 10 comprising a certain number of turns surrounding the tube 1. The coil is supplied by a multi-frequency sinusoidal exciting current via a current source 11 connected to its terminals. The electrical signals corresponding to the induced currents are processed by a a processing unit 12. In the case of this first embodiment of the device for measurement by Foucault currents, the mean value of the thickness of the cladding is measured, which incorporates possible variations in thickness at the circumference of the tube, or circumferential variations. Variations in thickness over the length of the coil 10, or axial variations, are likewise incorporated. According to this principle, the measurement is also sensitive to centering of the tube within the coil constituting the Foucault-current probe, so that this centering, even if carried out optimally, is likely to reduce the accuracy of the measurement. A second measurement technique, shown in FIG. 3B consists in using a coil 14 the axis of which extends radially with respect to the tube 1. The excitation of the coil by a multi-frequency sinusoidal current, by virtue of a current source 11', and the processing of the signals corresponding to the induced currents by a processing unit 12', are carried out in the same way as in the case of the measurement device shown in FIG. 3A. The device such as that shown in FIG. 3B makes it possible to carry out localized measurement of the thickness of the cladding of the tube 1. As shown in FIG. 3C, it is also possible to use a plurality of coils 15 similar to the coil 14 shown in FIG. 3B and fixed on a common support 16, so that the coils 15, the axes of which extend radially with respect to the tube 1, are arranged about the tube in regularly distributed circumferential positions. It is thus possible to carry out simultaneously thickness measurements at various points distributed about the circumference of the tube. It is also clear that it is possible to sweep the surface of the tube, for example by displacing the tube axially with respect to the Foucault-current probe, as shown by the arrow 13 in FIG. 3A. The frequency of the sinusoidal exciting signal, and the dimensions of the windings (diameter and height) are determined so as to optimize the sensitivity of the measurements to the variations in thickness of the cladding and to minimize variations of the measurement signals caused by variations in the distance between the coil and the surface of the tube, constituting an air gap. This air-gap or lift-off effect can be considerably reduced by an appropriate choice of frequency, is indicated in patent application FR-A-2,534,015. In order to improve the quality of the measurement and, in particular, in order to take into account possible variations in electrical conductivity of the alloys constituting the core and the cladding of the tubes, this electrical conductivity being very sensitive to the composition of the alloys, it is possible to use, in addition to the main exciting frequency as defined above, one or more auxiliary frequencies intended to compensate for the variations in composition on a same tube or within a same batch of tubes or within a same casting operation. The method according to the invention is therefore characterized by the use of a multi-frequency sinusoidal exciting signal having a main frequency and secondary frequencies. It is possible, in particular, to use a second frequency which is sensitive to the mean variation in conductivity of the alloys constituting the core and the cladding, this second frequency not being sensitive, or having a very low sensitivity, to the variations in thickness of the core and of the cladding. It is also possible to use two auxiliary frequencies, one of which is sensitive to the variation in conductivity of the base material constituting the core while at the same time being very slightly sensitive to variations in conductivity of the cladding and to variations in thickness of the core and of the cladding, and the other of which is sensitive only to variations in conductivity of the cladding. It is also possible to use a supplementary frequency to carry out measurements and compensations of the lift-off effect. The probe is excited simultaneously by each of the sinusoidal signals having the frequencies determined in the manner described above and the phase-measurement and amplitude-measurement signals corresponding to each of the sinusoidal signals of determined frequency are digitized and processed, as indicated above, by a processing module and by data-processing means which make it possible to deduce from these signals the thickness of the cladding. The measurement of the thickness of the cladding is obtained either by analysis of the phase of the signal corresponding to the Foucault currents, this method having the advantage of being less sensitive to the variations in lift-off, or by combined analysis of the phase and the amplitude of the signals corresponding to the Foucault currents. In a general manner, the device used for measuring the thickness of the cladding by Foucault currents comprises: a checking head containing the Foucault-current probes and ensuring the positioning of these probes on the tube, and the precise guiding of the tube, at least one Foucault-current probe fixed on the checking head, a source of multi-frequency exciting sinusoidal current, mechanical means for driving and accurate guidance of the tubes past the checking head, highly accurate means for checking the linear advance of the tubes and for measuring their axial position, and means for the acquisition and the data-processing of the resultant Foucault current measurements. The obtaining of an accurate value for the thickness e.sub.p, measured by Foucault currents and measurement of the passage time .delta.t of a longitudinal ultrasonic wave propagating in the total thickness of the jacket in a direction perpendicular to the surface, as shown in FIGS. 2A and 2B, makes it possible to obtain an accurate value for the total thickness of the jacket. This total thickness of the jacket e.sub.g is given by the formula e.sub.g =e.sub.p +(.delta.t-e.sub.p /V.sub.p).times.V.sub.a, in which e.sub.p represents the thickness of the cladding measured by Foucault currents, V.sub.p the speed of the longitudinal ultrasonic waves in the cladding material, V.sub.a the speed of the longitudinal ultrasonic waves in the material of the core of the tube, and .delta.t the propagation time of the ultrasonic wave in the total thickness of the jacket. In this formula, e.sub.p /V.sub.p represents the passage time of the ultrasonic wave in the cladding material, (.delta.t-e.sub.p /V.sub.p) represents the passage time of the ultrasonic wave in the core of the tube, (.delta.t-e.sub.p /V.sub.p).times.V.sub.a represents the thickness of the core, for an axial position of the tube which is perfectly determined by virtue of the means for checking and measuring the axial position. This calculation is, of course, only valid in the case where the speeds V.sub.p and V.sub.a are sufficiently different to give rise to significant errors during the measurement and calculation of the thickness of the tube. The method according to the invention also permits the detection of flaws in cohesion at the interface between the cladding and the core of the tube. The flaws in cohesion are plane, of a negligible thickness and arranged parallel to the surface of the tube. It would therefore be very difficult to detect these flaws by Foucault currents. An ultrasonic detection technique is therefore better suited, although the very small depth of the flaw beneath the surface of the tube corresponding to the thickness of the cladding layer (lying between 80 and 100 .mu.m) makes it difficult to detect flaws in cohesion at the interface. It is possible to use techniques for detection by the reflection of ultrasonic waves which are known per se and which are represented in FIGS. 4A, 5A and 6A and on the corresponding oscillograms of FIGS. 4B, 5B and 6B. The chief disadvantage of these reflection detection techniques lies in the need to use ultrasonic waves at a very high frequency, for example at a frequency greater than 100 MHz, which corresponds to wave lengths in the zirconium of less than 50 .mu.m. According to a first reflection detection technique, represented in FIGS. 4A and 4B, ultrasonic waves are emitted in substantially radial directions with respect to the tube, in other words with a substantially normal incidence. In FIG. 4A, an ultrasonic beam 21 has been shown, reflected on the outer surface of the tube, an ultrasonic beam 22 reflected on a flaw 20 situated at the interface 4 between the cladding layer 3 and the core 2 of the tube, and a beam 23 reflected on the inner surface of the tube, the corresponding echoes 24, 25 and 26 being shown in FIG. 4B. The echo signal 26 reflected by the inner surface of the tube has a smaller amplitude than the signal 24 reflected by the outer surface of the tube. The time lag between these two echoes corresponds to twice the passage time of the ultrasonic waves in the thickness of the tube. The echo signal 25 corresponding to a reflection on a flaw 20 at the interface 4 has a smaller amplitude and a very small time lag compared with the signal reflected on the outer surface of the tube because of the very small thickness of the cladding layer 3. This first method of detection is therefore limited by the fact that the flaw is very close to the outer surface of the tube, and hence by the fact that the corresponding echo 25 can be mixed with the echo 24 which has a large time width due to the effect of the electronic amplification of the ultrasonic signal. A second method, illustrated by FIGS. 5A and 5B, consists in using a beam of ultrasonic waves 27 with oblique incidence so that this beam is first reflected by the inner surface of the tube, then by the flaw 28 at the interface and again by the inner surface of the tube. In this case, the echo 29 corresponding to the reflection on the flaw 28 after an initial reflection on the inner surface of the tube, followed by a second reflection on the inner surface of the tube, has a considerable time lag compared with the echo 24. Similarly, the echo 29 and the immediately following echo 29' reflected by the inner surface of the tube have a small, equivalent amplitude and time width and can therefore be separated easily. This technique can, however, be difficult to implement depending on the nature of the flaw and insofar as it must be carried out with oblique incidence. It may also be necessary to use an ultrasonic transducer with a separate emitter and receiver. A third measuring method is illustrated by FIGS. 6A and 6B. The checking is carried out from the inside of the tube and the ultrasonic beam is emitted with normal incidence so as to obtain a direct reflection on the flaw 30. The echo 31 corresponding to the reflection on the flaw 20 has a smaller amplitude and a large time lag as compared with the signal reflected by the inner surface of the tube. Similarly, this echo 31 and the immediately following echo 31' resulting from the reflection on the outer surface of the tube have small, equivalent amplitudes and time widths and can therefore be separated easily. However, this detection method is difficult to implement in an industrial context, insofar as the checking must be effected from the inside of a tube of small diameter and of great length. It is thus difficult to obtain checking rates which are sufficient for use of the method on an industrial scale. Furthermore, the use of ultrasonic waves with very high frequencies has disadvantages in the case of the use of the method in an industrial environment, insofar as this method is sensitive to electronic interference. FIGS. 7A, 7B, 8A and 8B illustrate a technique for detecting flaws in cohesion at the interface between the cladding layer 3 and the core 4 of a duplex tube 1, by transmission of an ultrasonic wave in the wall of the duplex tube constituting a jacket for a fuel rod, the ultrasonic wave then being reflected on the inner surface of the tube, as can be seen in FIG. 7A which relates to a tube or part of a tube which has no flaw in cohesion. In this case, the oscillogram shown in FIG. 7B has a bottom echo 36, the amplitude of which, although less than the amplitude of the input echo 35, is considerable. The application of the method to a sound material therefore results in a virtually integral transmission of the ultrasonic wave at the interface between the cladding layer 3 and the core 2 of the tube. The reflection at the interface 4 is, in fact, negligible insofar as the acoustic impedences of the materials constituting the cladding layer 3 and the core 2 are very similar. Where a flaw in cohesion 37 exists at the interface 4' between the cladding layer 3' and the core 2' of a duplex tube 1', as shown in FIG. 8A, the ultrasonic wave emitted with a virtually normal incidence with respect to the outer surface of the tube cannot be transmitted, or is transmitted only very partially, at the flaw in cohesion 37 situated at the interface 4'. The ultrasonic energy is dissipated by the successive reflections in the thickness of the cladding layer 3'. A highly attentuated, or even non-existent, bottom echo 36' is then obtained. The input echo 35' is widened and represents the dissipation of the ultrasonic energy by successive reflections in the cladding layer. The method therefore makes it possible to distinguish very easily a sound material from a material having flaws in the cohesion. This transmission detection technique can be applied by using a beam of ultrasonic waves, the frequency of which is situated at an interval permitting easier implementation of the detection method compared with the reflection detection methods which have been described above. This range of frequencies can lie, for example, between 10 and 20 MHz. Moreover, it is possible to use the ultrasonic transducer with normal incidence, which has advantages for the ease of implementation of the method. These conditions correspond in practice to those which are currently used in the case of checking the thickness of the wall of a fuel rod jacket. FIG. 9 shows an ultrasonic transducer or sensor 40 which makes it possible to detect flaws in cohesion at the interface of a duplex tube 1. The sensor 40 is designed so as to obtain optimized focusing of the ultrasonic beam 41. Since the flaws in cohesion at the interface of the duplex tube 1 are elongated in the direction parallel to the axis of the tube and have a surface parallel to the surface of the tube, it is desired to obtain a focal spot 42 of oblong shape, the longitudinal axis of which extends accurately in a direction parallel to the axis of the tube. The surface 43 of the focusing lens of the sensor has the shape of a cylindrical sector, and the optimum adjustment of the focal spot is obtained by adjusting the orientation of the sensor so that the bottom echo (36 in FIG. 7B) has a maximum amplitude. Furthermore, the sensor must have a wide pass band, which is obtained by high damping. Very narrow echoes are thus obtained and, moreover, the input echo (35 in FIG. 7B) is clearly separated from the bottom echo (36 in FIG. 7B). A better display of the time widening of the input echo (echo 35' in FIG. 8B) upon passage over a flaw in cohesion such as the flaw 37 (FIG. 8A) is also obtained. The sensor 40 is mounted on a mechanical displacement assembly (not shown), which makes it possible, on the one hand, to effect a fine adjustment of the focusing of the sensor, of the alignment of the focal spot with respect to the axis of the tube, of the height of the coupling liquid such as water, in other words the distance between the sensor and the tube, and of the incidence of the beam and, on the other hand, to achieve accurate guidance of the tube as it passes by in the direction of its axis beneath the ultrasonic sensor 40. The invention, in its various embodiments, therefore makes it possible to check simply, quickly and accurately the thickness and the cohesion of the interface of a duplex tube by using simultaneously ultrasonic checking techniques and Foucault-current checking techniques. The implementation of the method and the device according to the invention can easily be achieved industrially, on a very large number of tubes of great length and of small diameter. It is possible to use ranges of frequencies of the ultrasonic waves which are different from those which have been mentioned and transducers having a form, structure and dimensions which are adapted to the tubes to be checked. These transducers or sensors can be associated with mechanical adjustment means of any type. The tube can be displaced in its longitudinal direction with respect to the sensor by guide means and drive means of any type. The position of the tube and of the zone being checked can be determined accurately by any suitable means. It is likewise clear that devices can be used for measuring the thickness of the cladding layer by Foucault currents of a type different from those which have been described. The processing modules and the data-processing means associated with the ultrasonic checking sensor and with the Foucault-current measuring means can consist of conventional components which digitize and process the signals, calculate the thickness, display the results in any form and indicate the presence of flaws in the form of easily recognizable messages. Lastly, the invention applies to the checking of any duplex tube used as a jacket element for fuel rods of assemblies for nuclear reactors or in any other field of industry. Similarly, these types of checking can be applied even more easily to larger tube diameters and thicknesses; the upper limit is fixed by the Foucault-current technique for measuring the thickness of the cladding, and this limit thickness is generally approximately 2 mm in the case of the abovementioned zirconium alloys. |
summary | ||
summary | ||
claims | 1. A drawing apparatus configured to perform drawing on a substrate with a plurality of charged particle beams, the apparatus comprising:an irradiation system including a collimator lens on which a diverging charged particle beam is incident;an aperture array configured to split the charged particle beam from the collimator lens into the plurality of charged particle beams;a lens array configured to form a plurality of crossovers of the plurality of charged particle beams from the aperture array; anda projection system including an element having a single aperture and configured to converge the plurality of charged particle beams corresponding to the plurality of crossovers and to project the plurality of charged particle beams having passed through the single aperture onto the substrate,wherein the lens array includes a correction lens array and a magnifying less array, the correction lens array including a converging lens eccentric relative to corresponding one of a plurality of apertures of the aperture array such that the plurality of charged particle beams converged according to aberration of the projection system are converged to the single aperture, and the magnifying lens array configured, so as to form the plurality of crossovers, to magnify a plurality of crossovers formed by the correction lens array, converging lenses included in the correction lens array having such focal lengths that the eccentric converging lens refracts a charged particle beam corresponding thereto, without shielding of the charged particle beam, so that the plurality of charged particle beams are converged to the single aperture, magnifying lenses included in the magnifying lens array having such focal lengths that the magnifying lenses respectively converge a plurality of charged particle beams, respectively converged by the converging lenses and then diverged, with convergent angles smaller than convergent angles of the plurality of charged particle beams respectively converged by the converging lenses. 2. The drawing apparatus according to claim 1, wherein the magnifying lens array includes a magnifying lens eccentric relative to corresponding one of the plurality of apertures of the aperture array such that a principal ray of a charged particle beam having passed through the converging lens passes through a center of the magnifying lens. 3. The drawing apparatus according to claim 1, wherein a magnifying lens included in the magnifying lens array is configured to have infinite magnification. 4. The drawing apparatus according to claim 1, further comprising:an aligner deflector configured to deflect the plurality of charged particle beams between the plurality of crossovers formed by the lens array and the magnifying lens array, to adjust positions of the plurality of crossovers. 5. A drawing apparatus configured to perform drawing on a substrate with a plurality of charged particle beams, the apparatus comprising:an irradiation system including a collimator lens on which a diverging charged particle beam is incident;an aperture array configured to split the charged particle beam from the collimator lens into the plurality of charged particle beams;a lens array configured to form a plurality of crossovers of the plurality of charged particle beams from the aperture array; anda projection system including an element having a plurality of apertures corresponding to the plurality of crossovers, and a plurality of projection units corresponding to the plurality of apertures and configured to project the plurality of charged particle beams from the plurality of apertures onto the substrate,wherein the lens array includes a correction lens array and a magnifying lens array, the correction lens array including a converging lens eccentric relative to corresponding one of the plurality of apertures of the element so as to align each of the plurality of crossovers formed via the aperture array, on which the charged particle beam is incident at incident angles according to aberration of the irradiation system, and via the lens array, with corresponding one of the plurality of apertures of the element, and the magnifying lens array configured, so as to form the plurality of crossovers, to magnify a plurality of crossovers formed by the correction lens array, converging lenses included in the correction lens array having such focal lengths that the eccentric converging lens refracts a charged particle beam corresponding thereto, without shielding of the charged particle beam, so that each of the plurality of charged particle beams is aligned with corresponding one of the plurality of apertures of the element, magnifying lenses included in the magnifying lens array having such focal lengths that the magnifying lenses respectively converge a plurality of charged particle beams, respectively converged by the converging lenses and then diverged, with convergent angles smaller than convergent angles of the plurality of charged particle beams respectively converged by the converging lenses. 6. The drawing apparatus according to claim 5, wherein an arrangement of magnifying lenses of the magnifying lens array is aligned with an arrangement of the plurality of apertures of the element. 7. The drawing apparatus according to claim 5, wherein the aperture array includes an aperture eccentric relative to the corresponding one of the plurality of apertures of the element with the converging lens. 8. The drawing apparatus according to claim 7, wherein the aperture array is disposed on a front focal plane of the correction lens array, and includes an aperture eccentric relative to the corresponding one of the plurality of apertures of the element by the same amount as that of the converging lens. 9. The drawing apparatus according to claim 5, wherein the collimator lens receives the charged particle beam from a crossover, deviating from a front focal plane of the collimator lens, of a charged particle beam. 10. The drawing apparatus according to claim 5, comprising:a plurality of groups arranged in parallel, each group including the irradiation system, the aperture array, the lens array, and the projection system. 11. The drawing apparatus according to claim 5, wherein the element includes a blanking deflector array. 12. The drawing apparatus according to claim 5, wherein the element includes a blanking stop aperture array. 13. A method of manufacturing an article, the method comprising:performing drawing on a substrate using a drawing apparatus;developing the substrate on which the drawing has been performed; andprocessing the developed substrate to manufacture the article,wherein the drawing apparatus is configured to perform drawing on the substrate with a plurality of charged particle beams, the apparatus comprises:an irradiation system including a collimator lens on which a diverging charged particle beam is incident;an aperture array configured to split the charged particle beam from the collimator lens into the plurality of charged particle beams;a lens array configured to form a plurality of crossovers of the plurality of charged particle beams from the aperture array; anda projection system including an element having a single aperture and configured to converge the plurality of charged particle beams corresponding to the plurality of crossovers and to project the plurality of charged particle beams having passed through the single aperture onto the substrate,wherein the lens array includes a correction lens array and a magnifying less array, the correction lens array including a converging lens eccentric relative to corresponding one of a plurality of apertures of the aperture array such that the plurality of charged particle beams converged according to aberration of the projection system are converged to the single aperture, and the magnifying lens array configured, so as to form the plurality of crossovers, to magnify a plurality of crossovers formed by the correction lens array, converging lenses included in the correction lens array having such focal lengths that the eccentric converging lens refracts a charged particle beam corresponding thereto, without shielding of the charged particle beam, so that the plurality of charged particle beams are converged to the single aperture, magnifying lenses included in the magnifying lens array having such focal lengths that the magnifying lenses respectively converge a plurality of charged particle beams, respectively converged by the converging lenses and then diverged, with convergent angles smaller than convergent angles of the plurality of charged particle beams respectively converged by the converging lenses. 14. A method of manufacturing an article, the method comprising:performing drawing on a substrate using a drawing apparatus;developing the substrate on which the drawing has been performed; andprocessing the developed substrate to manufacture the article,wherein the drawing apparatus is configured to perform drawing on the substrate with a plurality of charged particle beams, the apparatus comprises:an irradiation system including a collimator lens on which a diverging charged particle beam is incident;an aperture array configured to split the charged particle beam from the collimator lens into the plurality of charged particle beams;a lens array configured to form a plurality of crossovers of the plurality of charged particle beams from the aperture array; anda projection system including an element having a plurality of apertures corresponding to the plurality of crossovers, and a plurality of projection units corresponding to the plurality of apertures and configured to project the plurality of charged particle beams from the plurality of apertures onto the substrate,wherein the lens array includes a correction lens array and a magnifying lens array, the correction lens array including a converging lens eccentric relative to corresponding one of the plurality of apertures of the element so as to align each of the plurality of crossovers formed via the aperture array, on which the charged particle beam is incident at incident angles according to aberration of the irradiation system, and via the lens array, with corresponding one of the plurality of apertures of the element, and the magnifying lens array configured, so as to form the plurality of crossovers, to magnify a plurality of crossovers formed by the correction lens array, converging lenses included in the correction lens array having such focal lengths that the eccentric converging lens refracts a charged particle beam corresponding thereto, without shielding of the charged particle beam, so that each of the plurality of charged particle beams is aligned with corresponding one of the plurality of apertures of the element, magnifying lenses included in the magnifying lens array having such focal lengths that the magnifying lenses respectively converge a plurality of charged particle beams, respectively converged by the converging lenses and then diverged, with convergent angles smaller than convergent angles of the plurality of charged particle beams respectively converged by the converging lenses. |
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047755083 | abstract | This invention relates to a tubular water reactor fuel cladding having an outer cylindrical layer composed of a conventional zirconium base alloy. Bonded to the outer layer is a second, inner layer composed of an alloy consisting essentially of: about 0.1 to 0.3 wt. % tin; about 0.05 to 0.2 wt. % iron; about 0.05 to 0.4 wt. % niobium; about 0.03 to 0.1 wt. % of either chromium or nickel, alone or in combination with each other; while keeping the sum of the iron chromium and nickel contents below 0.25 wt. %; 300 to 1200 ppm oxygen; and the balance essentially zirconium. The inner layer is characterized by excellent resistance to PCI crack propagation, excellent aqueous corrosion resistance and a fully recrystallized microstructure. |
abstract | A method and system for achieving fusion is provided. The method includes providing laser source that generates a laser beam and a target that includes a capsule embedded in the target and filled with DT gas. The laser beam is directed at the target. The laser beam helps create an electron beam within the target. The electron beam heats the capsule, the DT gas, and the area surrounding the capsule. At a certain point equilibrium is reached. At the equilibrium point, the capsule implodes and generates enough pressure on the DT gas to ignite the DT gas and fuse the DT gas nuclei. |
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048521418 | claims | 1. A transportable shielding apparatus suitable for on-site assembly and use with an X-ray generator comprising: a shielded cone connectable to the X-ray generator and extending therefrom towards an object to be X-rayed located external to the cone, said cone comprising an upper cone support portion detachably connected to the X-ray generator, a lower cone support portion forming the base of the cone and a plurality of trapezoidal panels detachably connected to and extending between said upper and lower cone support portions said panels having interlocking edge portions extending along the length thereof. a shielded cone connectable to an output port of a radiation source and extending towards an object to be X-rayed located external to the cone, said cone comprising an upper cone support portion, a lower cone support portion, and a plurality of interlocking panels extending between said upper and lower cone support portions to form a hollow body, said panels having interlocking edge portions extending along the length thereof; a first shielding means covering the radiation source; and a second shielding means covering the port and simultaneously tightly engaging the radiation source. an upper cone support portion attached to the second shielding means; a lower cone support portion; and a plurality of interlocking panels forming a hollow body, said panels having interlocking edge portions along the length thereof, said panels being detachably connected to the upper cone support portion and lower cone support portion. 2. The apparatus as recited in claim 1 further comprising a shroud removably fitted to and extending about the X-ray generator. 3. The apparatus as recited in claim 2 further comprising a shielding cap covering a first end portions of the X-ray generator. 4. The apparatus as recited in claim 3 further comprising a tubehead shield detachably connected to the X-ray generator about an output port of the X-ray generator. 5. The apparatus as recited in claim 4 wherein said tubehead shield is connected to said upper cone support portion. 6. The assembly as recited in claim 5 wherein said shielding cap, shroud, tubehead shield, and cone cooperate to encapsulate the X-ray generator and X-rays emitted therefrom. 7. The apparatus as recited in claim 6 further comprising a holding fixture connected between said generator and said cone. 8. The apparatus as recited in the claim 7 wherein said holding fixture is connectable to a tripod. 9. The apparatus as recited in claim 1 wherein said upper and lower cone support portions each comprise a frame member having a truncated pyramid construction said first and second frame members being paced from each other and joined by the panels. 10. The transportable shielding apparatus as recited in claim 9 wherein said upper and lower cone support portions each comprise an outer surface and an inner surface, and wherein said panels are disposed adjacent the outer surface of the upper cone support portion and adjacent the inner surface of the lower cone support portion. 11. The apparatus as recited in claim 1 wherein said panels are joined solely by connection to said upper and lower cone support portions and along said panel edge portions. 12. A transportable collimator and shielding apparatus suitable for on-site assembly used to shield emitted rays comprising: 13. The apparatus as recited in claim 12, wherein the first shielding means comprises a shroud snugly and removably fitting said radiation source. 14. The apparatus as recited in claim 10, wherein said second shielding means detachably covers the output port and a portion of the radiation source. 15. The apparatus as recited in claim 14, wherein said second shielding means is formed of aluminum lined with lead. 16. The apparatus as recited in claim 14, wherein said second shielding means detachably engages said cone. 17. The apparatus as recited in claim 16, wherein said collimator cone comprises: 18. The apparatus as recited in claim 10 wherein said interlocking panels comprises a back bone panel, an opposite panel, and two outer panels, each of said panels having a generally trapezoidal shape. 19. The apparatus as recited on claim 18 further comprising means for interfacing the collimator cone to a structure to be X-rayed, said interfacing means including a plurality of overlapping flaps detachably engaged to the panels and extending perpendicular therefrom. 20. The apparatus as recited in claim 17 further comprising a holding fixture tightly secured to the source of radiation and to said collimating means. |
abstract | A lifting lug for a nuclear-waste container has a tubular body having an inner end formed with a flange adapted to be bolted to the container and a transverse wall set in and tightly fitted to a smaller-diameter outer end of the tubular body. The wall is a separate piece from the body and is press-fitted to the tubular body. The wall is mounted at a load point of the lifting lug. In addition the wall is formed of a disk and/or a ring, typically as one unitary piece with the disk and ring spaced from each other. |
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description | This disclosure relates generally to multi-leaf collimators of radiotherapy systems. More specifically, this disclosure relates to systems and methods for calibrating and controlling movement of leaves of a multi-leaf collimator. Radiotherapy is used to treat cancers and other ailments by irradiating tissue with ionizing radiation. Radiotherapy systems generate a beam of radiation (e.g. electrons, protons, ions, and the like) and direct the beam towards a target site, such as a tumour. To concentrate the radiation at the target site and to minimize irradiation of healthy surrounding tissue, radiotherapy systems often also include a beam-shaping device such as a multi-leaf collimator (MLC). A MLC includes rows of elongate leaves that are arranged side-to-side and constructed of a radiation-shielding material such as tungsten. Each leaf can be independently moved into and out of the path of the radiation to block a portion of the beam. By arranging the collimator leaves, the MLC can be used to shape the radiation beam in order to focus the dose on the target tissues. Given the importance of accurately controlling the beam shape, techniques have been developed to calibrate the positions of collimator leaves. For example, some radiation-based calibration techniques utilize x-ray film or point dosimeters to confirm that the leaves form the desired radiation beam shape. However, such techniques can be time-consuming and often provide a poor indication of the actual beam geometry. Other calibration techniques involve using a laser beam and optical detector to determine when the MLC leaves have reached a defined calibration position. However, this technique may not provide an accurate indication of the leaf positions for all leaf shape configurations. Still further calibration techniques involve imaging optical markers on the leaves with a camera and using the detected positions of the optical markers to determine the positions of the leaves. However, the lens of the camera can distort the images of the markers, meaning additional calibration steps may be necessary to provide accurate determination of the leaf positions. The extent of this distortion is different for each lens and can change every time adjustments are made to the camera; thus, a distortion correction technique developed for one camera may not be applicable to other cameras, or to the camera in question after servicing. In addition, because the optical markers are manually placed on the collimator leaves, the distance between the marker and the leaf tip (a distance known as the “minor offset”) is different for each leaf. Existing MLCs cannot simply measure the minor offset with the camera because the leaves are not visible to the camera. For these reasons, existing collimator systems may require computationally-intensive and time-consuming calibration steps to ensure that collimator leaves are correctly positioned during radiotherapy. Thus, there remains a need for improved techniques for accurately monitoring collimator leaf positions by minimizing the distortion of leaf images caused by the camera lens and by accurately measuring and accounting for the minor offsets of the leaves in a more timely fashion. The present disclosure provides systems and methods for generating undistorted images of collimator leaves and accurate measurements of the minor offsets using a minimal number of measurements, such that the true positions of the leaves can be determined without adding excessive calibration time to the machine setup process. As a result, the leaves can be even more accurately placed during radiotherapy so that the desired beam geometry can be achieved and the time required to perform the calibration may be reduced. Disclosed herein are systems and methods for correcting distortion of images of collimator leaves which is caused by the lens of a leaf-imaging camera, and for accurately measuring the minor offsets of the collimator leaves. Particular examples of the disclosure may enable accurate determination of the positions of the collimator leaves, thus providing more exact positioning of leaves to shape radiation beams during radiotherapy. According to an exemplary embodiment of the present disclosure, a computer-implemented method for calibrating leaves of a multi-leaf collimator of a radiotherapy device is provided, the leaves including imaging markers and configured to shape a radiation beam emitted by the radiotherapy device by blocking radiation, wherein the radiotherapy device includes an imaging device configured to image the leaves, the imaging device including a lens. The method includes receiving a plurality of images of the leaves from the imaging device. The leaves are in a first position in at least a first image and in a second position in at least a second image. The method further includes generating, based at least in part on the first image and the second image, initial position estimates of the leaves in the first position and in the second position. The initial position estimates of the leaves are generated with respect to a predetermined coordinate space associated with the multi-leaf collimator. The method further includes determining, based at least in part on the initial position estimates of the leaves in the first position and in the second position, offsets for the leaves. The offsets reflect differences between imaging marker positions of the leaves and positions of tips of the leaves. The method further includes identifying first position coordinates, with respect to the predetermined coordinate space, for the leaves based upon the offsets of the leaves and the initial position estimates of the leaves. The method further includes calculating a distortion coefficient of the lens based upon the first position coordinates for the leaves and the offsets of the leaves. The distortion coefficient reflects an optical distortion effect associated with the lens. The method further includes determining corrected position coordinates, with respect to the predetermined coordinate space, for the leaves based on the distortion coefficient and the first position coordinates for the leaves. The method further includes correcting the offsets for the leaves based on the corrected position coordinates for the leaves. The method further includes calibrating the multi-leaf collimator based on the corrected offsets, wherein at least one leaf of the multi-leaf collimator is controlled based on the calibration. The multi-leaf collimator includes two banks of leaves which are captured in the images. Two opposing leaves constitute a leaf pair. The first position is a retracted position of the leaves and the second position is an extended position of the leaves. A first bank of leaves moves into the retracted position in the first image and the extended position in the second image. A second bank of leaves moves into the extended position in the first image and the retracted position in the second image. Calculating the distortion coefficient includes identifying, in the predetermined coordinate space, a lens x-coordinate and a lens y-coordinate associated with a centre of the lens. Identifying the lens x-coordinate includes, for each leaf pair, generating a function based on the first position coordinates of the two opposing leaves in the first position and in the second position. Identifying the lens x-coordinate additionally includes identifying a maximum or a minimum of each function; determining an x-coordinate, relative to the predetermined coordinate space, of each maximum or minimum; and averaging the x-coordinates of the maximums and minimums. The function of each leaf pair is a second-order polynomial. Identifying the lens y-coordinate includes generating, for each bank of leaves in each of the first and second positions, a function based on the first position coordinates of the leaves; identifying a turning point for each function; and averaging the turning points. The function for each bank of leaves in each of the first and second positions is a second-order polynomial. Calculating of the distortion coefficient of the lens includes generating a function based on the first position coordinates and offsets of a selected one of the banks of leaves in one of the images; calculating a provisional distortion coefficient of the lens based on the function; determining an error value of the provisional distortion coefficient; if the error value is above a predetermined threshold, regenerating the function using the error value, recalculating the provisional distortion coefficient of the lens based on the regenerated function, and determining the error value of the recalculated provisional distortion coefficient until the error value is below the predetermined threshold; and when the error value is below the predetermined threshold, setting the distortion coefficient of the lens to be equal to the provisional distortion coefficient. The function is generated using a root mean square technique. Calculating the provisional distortion coefficient includes determining undistorted position coordinates, with respect to the predetermined coordinate space, for each leaf in the selected bank of leaves by minimizing, with the generated function, optical distortion associated with the lens; calculating a distortion coefficient of each leaf in the selected bank of leaves based on the undistorted position coordinates; and generating the provisional distortion coefficient of the lens by averaging the distortion coefficients of the leaves. The method additionally includes identifying the imaging marker positions of the leaves utilizing a predetermined conversion factor relating numbers of pixels and distance. Determining the offsets for the leaves includes identifying the imaging marker positions of the leaves, wherein each leaf is associated with at least two identified imaging marker positions; averaging, for each leaf, the imaging marker positions; identifying a reference leaf based on the average imaging marker positions; determining differences between the average imaging marker positions of the leaves and the average imaging marker position of the reference leaf; and calculating the offsets based on the determined differences. According to another exemplary embodiment of the present disclosure, a computer-implemented method for use in a radiotherapy device that emits a radiation beam to treat a target tumour of a patient is provided. The radiotherapy device includes a multi-leaf collimator having a plurality of leaves, the leaves including imaging markers and configured to shape the radiation beam emitted by the radiotherapy device by blocking radiation. The radiotherapy device includes an imaging device configured to image the leaves. The imaging device includes a lens. The method includes receiving a treatment plan for treating the target tumour with radiation. The treatment plan includes a therapeutic radiation beam shape for irradiating the target tumour. The method includes identifying radiotherapy position coordinates, with respect to a predetermined coordinate space associated with the multi-leaf collimator, for the leaves of the multi-leaf collimator. The leaves form the therapeutic radiation beam shape by blocking radiation when they are positioned at the radiotherapy position coordinates. The method includes receiving offsets for the leaves. The offsets reflect differences between imaging marker positions of the leaves and positions of tips of the leaves. The method includes receiving calibration coefficients based on leaf position data from multiple multi-leaf collimators. The method includes generating a position error function based on the calibration coefficients. The position error function indicates a leaf position error associated with an optical distortion effect of the lens. The method includes controlling the leaves to move to the radiotherapy position coordinates based on the offsets and the position error function. The multi-leaf collimator includes two opposing banks of leaves. Generating the position error function includes generating position error polynomials for the banks of leaves, wherein each position error polynomial is based on different calibration coefficients; receiving, from the imaging device, an image of the leaves; identifying distorted position coordinates, with respect to the predetermined coordinate space, for the leaves based upon positions of the imaging markers of the leaves in the image; and generating the position error function based on the position error polynomials and the distorted position coordinates of the leaves. Each bank of leaves is associated with three position error polynomials, and each position error polynomial is based on four calibration coefficients. The offsets of the leaves are determined, at least in part, from leaf position data obtained when the leaves are in a first position and upon leaf position data obtained when the leaves are in a second position. The position error function indicates a leaf position error of each leaf. The method additionally includes calculating corrected calibration coefficients to accommodate an adjustment of the multi-leaf collimator; and generating a corrected position error function based on the corrected calibration coefficients. Additional features and advantages of the disclosed embodiments will be set forth in part in the description that follows, and in part will be obvious from the description, or may be learned by practice of the disclosed embodiments. The features and advantages of the disclosed embodiments will be realized and attained by the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are examples and explanatory only and are not restrictive of the disclosed embodiments as claimed. The accompanying drawings constitute a part of this specification. The drawings illustrate several embodiments of the present disclosure and, together with the description, serve to explain the principles of the disclosed embodiments as set forth in the accompanying claims. Exemplary embodiments are described with reference to the accompanying drawings. In the figures, which are not necessarily drawn to scale, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. Wherever convenient, the same reference numbers are used throughout the drawings to refer to the same or like parts. While examples and features of disclosed principles are described herein, modifications, adaptations, and other implementations are possible without departing from the spirit and scope of the disclosed embodiments. Also, the words “comprising,” “having,” “containing,” and “including,” and other similar forms are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It should also be noted that as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. Exemplary embodiments generally relate to systems and methods for minimizing or eliminating distortion in images of collimator leaves caused by the lens of a leaf-imaging camera. In addition, exemplary embodiments generally relate to systems and methods for accurately determining minor offsets of collimator leaves. Embodiments of the present disclosure may enable accurate determination of leaf positions, both during calibration and radiotherapy. Additionally, exemplary embodiments generally relate to systems and methods for performing radiotherapy, during which the positions of collimator leaves are corrected with generated position error functions. FIG. 1 is a view of an exemplary radiotherapy system 100. System 100 may be a linear accelerator (LINAC) system or a combination magnetic resonance imaging (MRI) and linear accelerator system, known as an MR-LINAC. However, it will be appreciated that system 100 in the present disclosure is not limited to a LINAC or a MR-LINAC, and that the systems and devices disclosed herein may be used to enable any suitable radiotherapy system, or any suitable combination medical imaging and radiotherapy system. System 100 may include a chassis 102, which may support a radiation head 104 and a radiation detection panel 106. Radiation head 104 and detection panel 106 may be mounted opposite each other on chassis 102, with a rotational axis of chassis 102 positioned between them. Radiation head 104 may be configured to generate a radiation beam 122, such as according to a treatment plan, to deliver doses of radiation to a patient 124 supported by a couch 110. The treatment plan may be predetermined, or may be determined in real-time or just prior to treatment and may be adjusted during the course of treatment. Chassis 102 may be configured to rotate radiation head 104 and detection panel 106 about couch 110, to provide patient 124 with a plurality of varying dosages of radiation according to the treatment plan. For example, chassis 102 may be powered by one or more chassis motors such that chassis 102 is continuously rotatable around couch 110. In some embodiments, couch 110 may be motorized so that the patient 124 can be positioned with a tumour site at or close to the isocentre 126 of the radiation beam 122. Additionally or alternatively, simultaneously with rotation of chassis 102 about the patient 124, couch 110 may be moved along a translation axis into or out of the treatment area (i.e. parallel to the axis of rotation of the chassis). With this simultaneous motion, a helical radiation delivery pattern known in the art may be achieved for producing certain types of dose distributions. In some embodiments, system 100 may additionally include an imaging device. For example, system 100 may be configured as an MR-LINAC system. Exemplary system 100 may utilize MR images, CT images, and/or pseudo-CT images to monitor and control radiation delivered by radiation head 104. System 100 may additionally include a controller 140, which may be programmed to control, inter alia, radiation head 104, detection panel 106, couch 110, an imaging device, and the chassis motor. Controller 140 may perform functions or operations such as treatment planning, treatment execution, image acquisition, image processing, motion tracking, motion management, and/or other tasks involved in a radiotherapy process. Hardware components of controller 140 may include one or more computers (e.g., general purpose computers, workstations, servers, terminals, portable/mobile devices, etc.); processors (e.g., central processing units (CPUs), graphics processing units (GPUs), microprocessors, digital signal processors (DSPs), field programmable gate arrays (FPGAs), special-purpose or specially-designed processors, etc.); memory/storage devices such as a memory 142 (e.g., read-only memories (ROMs), random access memories (RAMs), flash memories, hard drives, optical disks, solid-state drives (SSDs), etc.); input devices (e.g., keyboards, mice, touch screens, mics, buttons, knobs, trackballs, levers, handles, joysticks, etc.); output devices (e.g., displays, printers, speakers, vibration devices, etc.); circuitries; printed circuit boards (PCBs); or other suitable hardware. Software components of controller 140 may include operation system software, application software, etc. Controller 140 may be programmed to control features of system 100 according to a radiotherapy treatment plan for irradiating a target tissue of a patient. The treatment plan may include information about a particular dose to be applied to a target tissue, as well as other parameters such as beam angles, dose-histogram-volume information, the number of radiation beams to be used during therapy, the dose per beam, and the like. Controller 140 may be programmed to control various components of system 100, such as chassis 102, radiation head 104, detection panel 106, and couch 110, according to the predetermined treatment plan. In some embodiments, controller 140 may be programmed to generate a treatment plan using images received from an imaging device. Alternatively or additionally, controller 140 may be programmed to acquire a treatment plan from memory 142 and to execute the plan with system 100. In some embodiments, controller 140 may be programmed to modify a treatment plan received from memory 142 prior to execution with system 100. FIG. 2 illustrates features of an exemplary radiation head 104 of system 100. Radiation head 104 may include a radiation beam generator 210 (e.g. an X-ray source) and a multi-leaf collimator (MLC) 200, at least one of which may be mounted on chassis 102. Radiation beam 122, generated by beam generator 210, may be a cone beam or a fan beam, for example. In other embodiments, radiation head 104 may include more than one beam generator and/or more than one respective multi-leaf collimator. MLC 200 may include a plurality of elongate leaves 202, 204 oriented orthogonal to the axis of beam 122. The leaves of MLC 200 may be controlled to take different positions to selectively block some or all of radiation beam 122, thereby altering the shape of the beam that reaches the patient. Radiation head 104 may also include a camera 220 configured to view collimator leaves 202, 204 via a pair of tilt-adjustable mirrors 222, 224, which may permit the camera to be located out of the radiation beam 122. In some embodiments, leaves 202, 204 may not be visible to camera 220; accordingly, leaves 202, 204 may include imaging markers mounted thereon, such as rubies or fluorescing markers, which may be visible to camera 220. A beam splitter 242 may be placed in the optical path (between the two mirrors 222, 224 so that it is also out of the radiation beam 122) such that a light projector 240 may illuminate the imaging markers along the same optical path. Radiation head 104 may include a further mirror or mirrors 244 so as to locate the light projector (and/or other elements) in convenient locations. According to embodiments in which leaves 202, 204 each include a ruby as an imaging marker, the ruby may be configured to fluoresce in the dark red/near infrared light band (e.g. 695 nm) when illuminated with light having a wavelength in the 525 nm green light band or in the 410 nm violet/near ultraviolet light band. For example, light projector 240 may irradiate the rubies with green or violet light such that the rubies fluoresce, emitting light which may be diverted to camera 220 by mirrors 222, 224. Camera 220 may generate image data of the leaves 202, 204 utilizing the light emitted by the rubies, and controller 140 may utilize the image data to determine the position of the leaves and to control movement of the leaves into or out of the path of radiation beam 122 so as to shape the beam (e.g. according to a predetermined treatment plan). It will be appreciated that radiation head 104 in the present disclosure is not limited to the leaf-imaging configuration depicted in FIG. 2, and that the systems and devices disclosed herein may include any suitable configuration to image the leaves of MLC 200. FIG. 3A is a top plan view of an exemplary leaf array of MLC 200, and FIG. 3B is a side view of an exemplary leaf 202. MLC 200 may include two banks 310, 320 of leaves, each of which may be individually extended into and out of the path of radiation beam 122 so that their respective tips 304 shape the cross-section of the beam by blocking portions thereof. The word “tip” may refer to a functional end of leaf 202 along a longitudinal axis thereof for purposes of forming a shaping window for radiation beam 122. The word “tip” does not necessarily refer to the end point of leaf 202 relative to the longitudinal axis thereof (that is, the point of the leaf 202 closest to the center of MLC 200), although in some embodiments it may refer to the end point of leaf 202 relative to the longitudinal axis thereof. In some embodiments, MLC 200 may include a bank of motors, each configured to move a corresponding one of the leaves. Movement of each leaf by the motors may be controlled by controller 140; for example, controller 140 may control placement of the leaf tips 304 via the motors to shape radiation beam 122 for irradiating a target tissue 300, such as according to a predetermined treatment plan. In some embodiments, leaves 202, 204 may be configured to be extended into the path of radiation beam 122 to a location beyond a halfway point between leaf banks 310, 320. This capability may allow the leaves 202, 204 to be fully closed together. Leaves 202, 204 may be constructed of a radiopaque material such as tungsten and may be arranged side-by-side relative to each other, in two opposing banks 310, 320; thus, areas beneath the leaves 202, 204 are not irradiated. Each leaf is positioned directly opposite a corresponding leaf in the other leaf bank; two opposing leaves constitute a leaf pair 325. Each leaf may be thin in its transverse (y) direction to provide high resolution and limit the size of unnecessarily irradiated tissue areas. Each leaf may also be deep in the (z) direction to provide effective radiation absorption. In some embodiments, each bank may include 80 leaves, resulting in 160 leaves in total; alternatively, MLC 200 may include more or fewer leaves. Each leaf 202, 204 may include a drive coupling 330 and a tungsten body 340 secured together. The drive coupling 330 may include two grooves 334, 346 configured to engage end stop bars which may limit movement of the leaf (discussed further below). The drive coupling 330 may additionally include a notch 332 near the rear end 336 thereof, the notch 332 being configured to engage the leaf motor. For example, the leaf motor may be connected to a leaf key which may be inserted into notch 332 and driven by the motor to move the leaf into and out of radiation beam 122. Tungsten body 340 may include an imaging marker 342 (e.g. a ruby) positioned near the leaf tip 304. The imaging marker 342 of each leaf is manually placed approximately a predetermined distance from leaf tip 304. For example, imaging marker 342 may be placed such that its centre is approximately 4.5 millimeters from leaf tip 304. However, because each imaging marker is manually placed, the minor offset 344 between the centre of imaging marker 342 and the leaf tip 304 may be different for each leaf. Camera 220 cannot measure minor offset 344 by imaging the position of the leaf tip 304 because leaf 202 is not visible to the camera 220 except for imaging marker 342. FIG. 4A is a top plan view of leaf banks 310 and 320, with their tips 304 aligned in two straight lines. For example, each leaf depicted in FIG. 4A may be in a respective fully retracted position. FIG. 4B is an image of imaging markers 342, as captured by camera 220. In the configuration depicted in FIG. 4A, imaging markers 342 of the leaves are approximately aligned on two straight lines because the markers are roughly the same distance from the aligned tips. As depicted in FIG. 4B, camera 220 captures an image of markers 342. However, the lens of camera 220 distorts the image of markers 342: markers 342 appear, in the image, to form two curved lines, rather than two approximately straight lines. This distortion effect, which is known as “barrel distortion” and which is illustrated in FIG. 4C, compresses image features to appear closer to the centre 400 of the image the further they are from the x coordinate axis 402 and y coordinate axis 404 of the image. Thus, as depicted in FIG. 4C, straight lines 406 are distorted to appear as curved lines 408, with the curve becoming more pronounced the further the line extends away from the x-axis 402 and y-axis 404 of the image. The barrel distortion effects are different for each camera lens and can make it difficult to determine the true positions of the collimator leaves, especially for the leaves furthest from the centre of the collimator. Therefore, in order to accurately locate and position the collimator leaves, the barrel distortion must be quantified and removed. FIG. 5A illustrates an exemplary calibration method 500A for a multi-leaf collimator (e.g. MLC 200) in which the barrel distortion and minor offsets may be quantified and used to correct the detected positions of the collimator leaves. Method 500A may be a processor-executed method. In some embodiments, method 500A may be executed by the same processor, such as controller 140. Alternatively, one or more steps of method 500A can be executed by separate processors. In step 502, controller 140 may control movement of the collimator leaves and may receive images of the leaves from camera 220. The controller may identify position data of the imaging markers 342 from the received images. Step 502 may include receiving two or more images of the leaves from camera 220. Controller 140 may be programmed to control MLC 200 such that each bank of leaves 310, 320 may be in a different position in each of the images. Optionally, controller 140 may store the position data of the imaging markers in memory 142. FIG. 6A illustrates an exemplary process of step 502. The process of FIG. 6A may be executed by a processor, such as controller 140. In step 602, controller 140 may retract a first bank of leaves (e.g. leaf bank 310) to an outer end stop 622. In step 604, controller 140 may advance the other bank of leaves (e.g. leaf bank 320) to an inner end stop 624. In some embodiments, leaves in the advancing bank (e.g. leaf bank 320) may be advanced beyond the halfway point between the leaf banks 310, 320 when they are advanced to the inner end stop 624. Controller 140 may move the leaves, including advancing and retracting the leaves to the end stops, by actuation of the leaf motors of system 100. FIGS. 6B and 6C illustrate a first exemplary configuration of retracted and extended leaves. Each leaf bank 310, 320 may include an outer end stop 622 and an inner end stop 624. The end stops 622, 624 may be situated perpendicular to the longitudinal axis of the leaves and may limit movement of the leaves. For example, outer end stop 622 may engage groove 334 on the rear end 336 of drive coupling 330, and may define the fully retracted position of the leaves because the leaves cannot be retracted away from the collimator centre beyond outer end stop 622. Inner end stop 624 may engage groove 346 and may define the fully extended position of the leaves because the leaves cannot be advanced towards the collimator centre past inner end stop 624. However, one of ordinary skill will appreciate that the configurations of leaves 202, 204 and of end stops 622, 624 are merely exemplary, and that the systems and devices disclosed herein may include any suitable configuration to define fully retracted and fully extended positions of the collimator leaves. In step 602 (FIG. 6A), controller 140 may retract leaf bank 310 away from the collimator centre until grooves 334 of the drive couplings 330 engage outer end stop 622, as illustrated in the cross-sectional view of FIG. 6C. In step 604, controller 140 may advance leaf bank 320 towards the collimator centre until grooves 346 of the leaves in the bank engage inner end stop 624. In this arrangement, leaf tips 304 and rear ends 336 of the leaves in each bank may be aligned in straight lines because the leaves are identically shaped and dimensioned (with the exception of the manual placement of imaging marker 342). In step 606, controller 140 may control camera 220 to capture a first image of the leaves and may receive the image from camera 220. In some embodiments, controller 140 may store the first image in memory 142. FIGS. 6D and 6E illustrate steps 608-612. In step 608, controller 140 may advance bank 310 until grooves 346 of the leaves in the bank engage inner end stop 624, as illustrated in the cross-sectional view of FIG. 6E. In some embodiments, leaves in the advancing bank (e.g. leaf bank 310) may be advanced beyond the halfway point between the leaf banks 310, 320 when they are advanced to inner end stop 624. In step 610, controller 140 may retract leaf bank 320 away from the collimator centre until grooves 334 of leaves in the bank engage outer end stop 622. In step 612, controller 140 may control the camera 220 to capture a second image of the leaves and may receive the image from camera 220. In some embodiments, controller 140 may store the second image in memory 142. One of ordinary skill will understand that controller 140 may execute steps 608-612 prior to executing steps 602-606. In addition, controller 140 may control camera 220 to capture more than two images of the leaves. For example, controller 140 may image banks 310 and 320 separately in their respective fully extended and fully retracted configurations, resulting in four total images. However, at a minimum, two images of the leaves must be collected because the leaves must be imaged in at least two different positions. Referring again to FIG. 5A, in step 504, controller 140 may identify the positions of imaging markers 342 within the images received in steps 606 and 612. Controller 140 may identify the positions of the imaging markers in both banks of leaves in the retracted and advanced positions. Thus, for a given leaf of MLC 200, controller 140 may identify the imaging marker position from the image of that leaf in the advanced position and may identify the imaging marker position from the image of that leaf in the retracted position. Controller 140 may convert the imaging marker position data from pixels to a unit of distance, such as millimeters or microns, using a predetermined conversion factor. In some embodiments, the conversion factor may be constant for all leaves of MLC 200. The conversion factor may be calculated from a measured distance of a leaf travel trajectory in millimetres (which may be determined based upon the known dimensions of MLC 200) and a measured distance of the same leaf travel trajectory in pixels (which may be captured by camera 220 and corrected in accordance with, for example, method 500A). Additionally or alternatively, a conversion factor may be estimated from a number of MLCs and averaged or otherwise combined to produce the conversion factor. In step 504, controller 140 may determine x and y position coordinates for the imaging markers, with respect to a predetermined coordinate space 520 associated with MLC 200, based upon the converted imaging marker position data. Each leaf of MLC 200 may be associated with two sets of imaging marker position coordinates: one set of imaging marker position coordinates representing when the leaf is fully advanced and another set of imaging marker position coordinates representing when the leaf is fully retracted. In some embodiments, controller 140 may store the imaging marker position coordinates in memory 142. In some embodiments, controller 140 may perform the pixel-to-distance conversion of step 504 prior to determining the imaging marker position coordinates. In alternative embodiments, controller 140 may determine the imaging marker position coordinates in pixels, and may perform steps 506-514 of method 500A, and optionally step 516 of method 500A, using measurements and calculations in pixels. In such embodiments, controller 140 may then perform the pixel-to-distance conversion prior to performing the leaf control of step 518. In some embodiments, controller 140 may receive multiple images of the leaves at step 606 and at step 612. For example, controller 140 may receive 2 images, 3 images, 4 images, 5 images, 10 images, 25 images, 50 images, 100 images, or some other number of images at step 606 and at step 612. Controller 140 may execute step 504 of method 500A for each image received in steps 606 and 612 and may thus calculate imaging marker position coordinates for imaging marker 342 in each received image. In some embodiments, the imaging marker position coordinates from each image of a given leaf at a given position (e.g., from each image of the first leaf of left bank 310 in the retracted position) may be averaged to generate a more accurate set of position coordinates for the imaging marker of each leaf at each position. The average imaging marker position coordinates may be utilized by controller 140 in executing the remainder of method 500A. FIG. 5B depicts an exemplary predetermined coordinate space 520 associated with MLC 200, with the position coordinates for each imaging marker 342 mapped therein. The position coordinates of the imaging markers may be affected by the barrel distortion of the camera lens. For example, in a MLC with 80 leaves per leaf bank, markers of the first leaf 522 and 80th leaf 528 may appear closer to the y-axis than markers of the 40th leaf 524 and 41st leaf 526, though in reality the markers may be placed in approximately straight lines. The imaging marker position coordinates for a first bank of leaves (e.g. leaf bank 310) may have negative x-coordinates (i.e. are positioned to the left of the y-axis), while the imaging marker position coordinates for a second bank of leaves (e.g. leaf bank 320) may have positive x-coordinates (i.e. are positioned to the right of the y-axis). In some embodiments, controller 140 may determine imaging marker position coordinates with the origin 530 of the coordinate space 520 corresponding to the position of the collimator centre. In a MLC with 80 leaves per leaf bank (160 leaves total), the collimator centre may be located between the 40th leaf 524 and the 41st leaf 526, relative to an axis perpendicular to longitudinal directions of the leaves, and may be located equidistantly between the two leaf banks 310, 320. In some alternative embodiments, controller 140 may position origin 530 at a point which is equidistant between leaf banks 310, 320 and above first leaf 522 (relative to FIG. 5B) or below 80th leaf 528 (relative to FIG. 5B). Thus, the imaging marker position coordinates in coordinate space 520 may be assigned relative to the collimator centre. Returning to method 500A in FIG. 5A, controller 140 may transform the imaging marker position coordinates from the bipolar coordinate system to a mechanical coordinate system in step 506, so as to correct the x-coordinates of markers measured relative to the negative portion of x-axis 402 (i.e. markers in leaf bank 310). Controller 140 may execute this transformation by multiplying the x-coordinates of the imaging markers in leaf bank 310 by −1. In some alternative embodiments, controller 140 may execute the bipolar-to-mechanical transformation at a different step of method 500A, such as at the beginning of step 512. Controller 140 may calculate minor offset values for leaves in step 508. FIG. 7 illustrates an exemplary process of calculating the minor offsets in step 508. The leaves of MLC 200 may be identically shaped and dimensioned; for example, the leaf length 720, length 722 of drive coupling 330, and length 724 of body 340 may be constant for all leaves of MLC 200. However, because each marker 342 is manually and individually placed, minor offset 344 may vary across the leaves. At step 702, controller 140 may obtain the imaging marker position coordinates determined in step 504. The obtained imaging marker position coordinates may include the imaging marker position coordinates for the imaging marker of each leaf at each position (that is, in the advanced position and in the retracted position). In step 704, for one bank of leaves, controller 140 may calculate a temporal offset valve offsettemp for the imaging marker of each leaf. Controller 140 may calculate offsettemp for a given marker according to the following: offest temp = x outer - x inner 2 where xouter represents the x-coordinate of the marker when the leaf is at the fully retracted position and xinner represents the x-coordinate of the marker when the leaf is at the fully advanced position. Thus, offsettemp may be considered an average x-coordinate for the marker of a given leaf. Offsettemp has a positive value. In step 706, controller 140 may identify a reference marker from among the imaging markers 342 in the bank. In some embodiments, the reference marker may be the imaging marker with the largest offsettemp value (that is, the imaging marker with the x-coordinate which is furthest from the y-axis of coordinate space 520). In some alternative embodiments, the reference marker may be the imaging marker with the smallest offsettemp value (that is, the imaging marker with the x-coordinate which is closest to the y-axis of coordinate space 520). In step 708, controller 140 may calculate the minor offsets 344 for the remaining leaves in the bank. In some embodiments, the reference marker may be assumed to have a predetermined minor offset. For example, the leaves of MLC 200 may be manufactured such that each marker 342 is placed approximately a predetermined distance (e.g. 4.5 millimeters) from the leaf tip 304. Controller 140 may assume that the reference marker has a minor offset 344 equal to this distance (e.g. 4.5 millimeters) and may utilize the offsettemp values of the reference leaf and of the remaining leaves in the bank to calculate the minor offsets 344 of the other leaves. In some embodiments, controller 140 may determine longitudinal distances (i.e. distances along the x-axis of coordinate space 520) between offsettemp of the reference marker and the offsettemp values of the other markers in the bank. Controller 140 may then subtract the determined longitudinal distances from the predetermined distance to calculate the minor offsets of the leaves. According to an example in which the predetermined distance is 4.5 millimetres, if the controller determines that the offsettemp of a given marker is 0.3 millimeters from the offsettemp of the reference marker, controller 140 may determine that the given marker has a minor offset of 4.2 millimeters (i.e. 4.5 mm-0.3 mm). The controller may perform this calculation for all leaves in the bank. In step 710, controller 140 may calculate the minor offsets for the leaves in the other bank according to steps 704-708. As mentioned above, in some alternative embodiments of step 706 the marker closest to the collimator centre may be selected by controller 140 as the reference marker. In such embodiments, controller 140 may assume that the reference marker has a minor offset equal to the predetermined distance (e.g. 4.5 millimeters) and may add the determined longitudinal distances between the reference marker and the remaining markers to the predetermined distance to calculate the minor offsets of the leaves in step 708. For example, if it is determined that offsettemp of a given marker is 0.1 millimeter from offsettemp of the reference marker, controller 140 may determine that the given marker has a minor offset of 4.6 millimeters (i.e. 4.5 mm+0.1 mm). Controller 140 may perform this calculation for all remaining leaves in the bank. In step 710, controller 140 may calculate the minor offsets for the leaves in the other bank Advantageously, controller 140 may identify the imaging marker with the largest temporal offset value (that is, the marker which is furthest from the collimator centre) as the reference marker in some embodiments because the leaf of that marker is likely to be in the fully retracted configuration. Because the leaves themselves are not visible to camera 220, it cannot be confirmed with camera 220 that all of the leaves are actually in contact with outer end stop 622 when in the fully retracted position. It is highly likely that the leaf with the imaging marker furthest from the collimator centre is in the fully retracted position, since the imaging marker is drawn away from the collimator centre when the leaf is retracted towards outer end stop 622. Therefore, the determined minor offset of the reference marker is highly likely to be accurate, allowing calculation of the other minor offset values to be accurate as well. Returning to method 500A of FIG. 5A, in step 510 controller 140 may calculate leaf position coordinates corresponding to the position of tips 304 of the collimator leaves relative to coordinate space 520. The leaf position coordinates may include an x-coordinate and a y-coordinate of each leaf tip 304. For a given leaf at a given position (that is, either the advanced position or the retracted position), the value of the minor offset may be subtracted from the value of the imaging marker x-coordinate to determine the value of the leaf position x-coordinate. In this way, the minor offset may be corrected for and the x-coordinate of the leaf tip identified. For a given leaf at a given position, the value of the leaf position y-coordinate may be equal to the value of the imaging marker y-coordinate. Because minor offset only distorts calculation of the leaf position along the x-axis, the y-coordinates of the leaves do not require correction for the minor offset. Controller 140 may calculate leaf position coordinates for each leaf in the advanced position and in the retracted position. That is, each leaf of MLC 200 may be associated with two sets of leaf position coordinates: one set coordinates representing when the leaf is fully advanced and another set of coordinates representing when the leaf is fully retracted. Once the leaf position coordinates are determined, a distortion coefficient which quantifies the barrel distortion effect associated with the camera lens may be determined in step 512. FIG. 8 illustrates an exemplary process of calculating a distortion coefficient kin step 512. Distortion coefficient k characterizes the barrel distortion behavior of the lens and is different for each lens. Distortion coefficient k can be approximated to a third degree Taylor series and expressed by the following formula:rdistorted=rundistorted·(1+k·rundistorted2)where rdistorted is the radius of a point from the lens centre for a distorted image, and rundistorted is the radius of a point from the lens centre for an undistorted image. Since barrel distortion compresses an image, rdistorted is smaller than rundistorted. Since both radii are, by definition, positive: r distorted < r undistorted ⇒ r distorted r undistorted < 1 ⇒ ⇒ 1 + k · r undistorted 2 < 1 ⇒ k · r undistorted 2 < 0 ⇒ k < 0 Thus, distortion coefficient k must be less than 0. By determining distortion coefficient k of the lens, the barrel distortion can be quantified and removed. Calculation of distortion coefficient k may be performed with the imaging marker positions represented in pixels or in a unit of distance (e.g. microns); however, all calculations must be made in the same units. Prior to executing step 802 depicted in FIG. 8, controller 140 may perform the bipolar-to-mechanical transformation, if the transformation was not performed earlier in method 500A. In step 802, controller 140 may determine x- and y-position coordinates of the lens centre within to coordinate space 520. The lens centre represents the origin of the distortion introduced by the lens of camera 220; that is, the lens centre is the point of the lens through which light passing through the lens is undistorted. In some cases, the lens centre may be at origin 530; in other cases, it may be at a different location in coordinate space 520. Either the x-coordinate or the y-coordinate of the lens centre may be calculated first by controller 140. An exemplary method of calculating the x-coordinate of the lens centre in step 802 is depicted in FIG. 9A. For each leaf pair 325 in MLC 200, controller 140 may generate a function representing a fit between the four sets of leaf position coordinates, the four sets of coordinates including the coordinates for each leaf in the retracted position and in the advanced position. For example, for leaf pair 325 depicted in FIG. 9A, position 902 may represent the position coordinates of the first leaf in the fully extended position, and position 904 may represent the position coordinates of the first leaf in the fully retracted position. Similarly, position 906 may represent the position coordinates of the second leaf in the fully extended position, and position 908 may represent the position coordinates of the second leaf in the fully retracted position. Controller 140 may generate a function 910 that represents a fit between the four points 902-908. In some embodiments, function 910 may be a second-order polynomial function. Controller 140 may generate a function 910 for each leaf pair in MLC 200. Controller 140 may then identify a maximum or minimum 912 (depending on the curvature) of each generated function 910. In some embodiments, due to the barrel distortion effect, controller 140 may identify a maximum for each leaf pair 325 above the x-axis of coordinate space 520, and a minimum for each leaf pair 325 below the x-axis of coordinate space 520. In a MLC with 80 leaves per bank, controller 140 may identify 80 maximum or minimum values 912. Controller 140 may then average the x-coordinates of all of the identified maximum or minimum values 912 to determine the x-coordinate of the lens centre. In some embodiments, controller 140 may determine if the identified maximum or minimum for a function 910 is found on an edge of the coordinate space 520. This may occur due to rotation of an image collected in step 502 and/or due to marker detection errors. Controller 140 may correct for the rotation and marker detection errors, recalculate the maximum or minimum of the function 910, and utilize the recalculated maximum or minimum in determining the x-coordinate of the lens centre. In some embodiments, if controller 140 determines that the calculated x-coordinate of the lens centre is more than a predetermined distance from the origin 530, controller 140 may determine that the calculated x-coordinate of the lens centre is inaccurate. In such a case, controller 140 may default the x-coordinate of the lens centre to be equal to zero. An exemplary method of calculating the y-coordinate of the lens centre in step 802 is depicted in FIG. 9B. For each bank of leaves in each image, controller 140 may generate a function representing a fit between the position coordinates of all of the leaves in the bank. For example, in FIG. 9B, 310A may represent the position coordinates of the leaves in bank 310 when the bank is in the fully extended position, and 310B may represent the position coordinates of the leaves in bank 310 when the bank is in the fully retracted position. Similarly, 320A may represent the position coordinates of the leaves of bank 320 when the bank is in the fully extended position, and 320B may represent the position coordinates of the leaves of bank 320 when the bank is in the fully retracted position. In FIG. 9B, the leaf position coordinates of 310A (which are associated with first bank 310) may be situated to the right of the leaf position coordinates of 320A (which are associated with second bank 320) because the leaves of MLC 200 may be configured to advance beyond the midway point between banks 310, 320 when moving into their respective fully-advanced positions. Controller 140 may generate a function 920 which represents a fit between the leaf position coordinates of all leaves in a given bank at a given position. In the example depicted in FIG. 9B, controller 140 may generate four functions 920, two for each leaf bank 310, 320. In some embodiments, function 920 may be a second-order polynomial function. Controller 140 may then identify a turning point 922 for each generated function 920. For example, turning point 922 may be the position on function 920 with the largest x-value. Controller 140 may then average the y-coordinates of all of the turning points 922 to determine the y-coordinate of the lens centre. Controller 140 may then perform steps 804-812 to determine distortion coefficient k of the camera lens. Controller 140 may determine distortion coefficient k only utilizing the leaf position coordinates for one bank of leaves in a single image. Controller 140 may calculate input coordinates xinput and yinput for the tip of each leaf as follows:[xinput,yinput]=[xmeasured−xlens,ymeasured−ylens]where xmeasured and ymeasured are the leaf position coordinates obtained in step 510 and) xlens and ylens are the x- and y-coordinates of the lens centre determined in step 802. Controller 140 may then generate distorted coordinates xdistorted and ydistorted for the tip of each leaf; for each leaf, xdistorted and ydistorted may be set equal to xinput and yinput, respectively. In step 804, for each leaf in the one bank, controller 140 may determine a distorted radius rdistorted and angle θ of the leaf tip from the origin 530 as follows: r distorted = ( x distorted - x lens ) 2 + ( y distorted - y lens ) 2 θ = ( y distorted - y lens ) ( x distorted - x lens ) In step 806, controller 140 may fit the distorted x- and y-coordinates of the leaf tips to a straight line using the root mean square method, and may calculate the slope m of the fit line. In some embodiments, the fit line may not be vertical due to, among other things, slight rotation of camera 220 relative to the collimator leaves. Controller 140 may also identify the leaf tip in the bank having an x-coordinate which is furthest from origin 530 (that is, the leaf tip with the largest x-coordinate value). This leaf may be the leaf that is least distorted by the barrel distortion, since barrel distortion tends to compress images towards the image centre. Controller 140 may store the x-coordinate of this leaf tip as a variable offset. Controller 140 may then generate a straight line with slope m and with an x-intercept equal to offset. From this line, undistorted x- and y-coordinates for each leaf tip may be calculated by controller 140 as follows:xundistorted=ydistorted·m+offsetyundistorted=xundistorted·cos(θ) In steps 808 and 810, based upon the undistorted x- and y-coordinates of the leaf tips, controller 140 may calculate a provisional distortion coefficient ktemp based upon the relationship between distorted and undistorted radii of the leaves. Provisional distortion coefficient ktemp is an approximation of the distortion coefficient of the lens of camera 220. In some embodiments, controller 140 may execute a recursive function which recalculates ktemp until an associated error value Ek is determined to be below a predetermined threshold, at which time the corrected provisional distortion coefficient ktemp may be stored as distortion coefficient k of the lens. For each leaf, rdistorted and rundistorted may be related as follows:rdistorted=rundistorted+k·rundistorted3⇒rdistorted−rundistorted=k·rundistorted3 Specifying this relationship only for the x-coordinate for each leaf tip, following these steps:rdistorted−rundistorted=k·rundistorted3⇒⇒(rdistorted−rundistorted)·cos(θ)=(k·rundistorted3)·cos(θ)Considering: x undistorted = r undistorted · cos ( θ ) ⇒ cos ( θ ) = x undistorted r undistorted A ) r undistorted = x undistorted 2 + y undistorted 2 B ) It follows that, for each point in a line: x distorted - x undistorted = k · r undistorted 3 · cos ( θ ) = k · r undistorted 3 · x undistorted r undistorted = = k · r undistorted 2 · x undistorted = k · ( x undistorted 2 + y undistorted 2 ) · x undistorted = k · ( x undistorted 3 + y undistorted 2 · x undistorted ) Accordingly, in step 808 controller 140 may calculate a lens distortion coefficient kleaf for each leaf in the one bank according to the following: k leaf = x input - x undistorted ( x undistorted 3 + y undistorted 2 · x undistorted ) In step 810, controller 140 may average the lens distortion coefficient kleaf for all of the leaves in the one bank to determine the provisional lens distortion coefficient ktemp. Having calculated ktemp, controller 140 may calculate an error value Ek associated with ktemp and compare it to a predetermined threshold. Controller 140 may utilize ktemp to update rundistorted and rdistorted for each leaf for a subsequent iteration of the recursive function, based upon the undistorted x- and y-coordinates:rundistorted=√{square root over (xundistorted2+yundistorted2)}rdistorted=rundistorted+ktemp·rundistorted3 For each leaf, controller 140 may calculate new xdistorted and ydistorted values based upon the following relationships: r distorted = ( x distorted - x lens ) 2 + ( y distorted - y lens ) 2 θ = ( y distorted - y lens ) ( x distorted - x lens ) The x- and y-coordinates of the lens centre (xlens and ylens) and the angle θ for each leaf tip may remain constant in each iteration of the recursive function. Thus, controller 140 may utilize the updated rdistorted value for each leaf to calculate the new xdistorted and ydistorted values for each leaf tip. To determine the error Ek of ktemp, controller 140 may utilize the input values and the new distorted values for the tips of the first and final leaves of the bank. Thus, in an MLC with 80 leaves per bank, controller 140 may determine Ek based upon values of the first and 80th leaves as follows: E k = ( x input , 1 - x distorted , 1 ) + ( x input , 80 - x distorted , 80 ) 2 If controller 140 determines that Ek is below a predetermined threshold (e.g. less than 0.001), ktemp may be determined to be accurate, and controller 140 may store ktemp as the distortion coefficient k of the camera lens. However, if Ek is not below the predetermined threshold, controller 140 may update the offset value as follows:offset=offset+Ek Controller 140 may utilize the updated offset value and the updated xdistorted and ydistorted values for each leaf to calculate new xundistorted and yundistorted values for each leaf tip. The slope m of the fit line, the x- and y-coordinates of the lens centre (xlens and ylens), and the angle θ, xinput, and yinput values for each leaf may remain unchanged in each iteration. Controller 140 may repeat steps 806-810 using updated values to recalculate ktemp until controller 140 determines that Ek is less than the predetermined threshold, Controller 140 may then store ktemp as the distortion coefficient k of the lens of camera 220. Distortion coefficient k may remain accurate until camera 220 and/or the camera lens is adjusted or replaced, or when another component of the leaf-imaging configuration, such as light projector 240 or one of mirrors 222, 224, 242, or 244 is adjusted or replaced. Such changes may affect the distortion effect, causing k to change. Accordingly, on such an occasion controller 140 may recalculate the distortion coefficient k. Referring to step 514 in FIG. 5A, controller 140 may utilize the calculated) xlens, ylens, and k values to correct the optical distortion for each leaf in MLC 200. Controller 140 may calculate rdistorted and rundistorted values for the tip of each leaf in MLC 200 according to the following:[xinput,yinput]=[xmeasured−xlens,ymeasured−ylens]rdistorted=√{square root over ((xinput)−xlens)2+(yinput−ylens)2)}rdistorted=rundistorted·(1+k·rundistorted2)=rundistorted+k·rundistorted3 where xmeasured and ymeasured are the leaf position coordinates obtained in step 510. Controller 140 may solve these equations to determine the undistorted radius rundistorted for each leaf tip. Controller 140 may also calculate an angle θ for each leaf tip, which may be the same for both the distorted and undistorted position coordinates, as follows: θ = atan ( y distorted x distorted ) Controller 140 may determine undistorted x- and y-coordinates (“corrected leaf position coordinates”) for each leaf tip as follows:xundistorted=rundistorted·cos(θ)yundistorted=rundistorted·sin(θ)The corrected leaf position coordinates xundistorted and yundistorted may represent the true x- and y-position coordinates of each leaf tip within coordinate space 520, having been corrected to account for the optical distortion of camera 220. In step 514, controller 140 may additionally recalculate the minor offset for each leaf by determining a distance, along the x-axis, between the imaging marker x-coordinate and xundistorted. In some embodiments, controller 140 may calculate the minor offset for the leaf in the retracted position and for the leaf in the advanced position, and may average the two values to generate a corrected minor offset value. Advantageously, this recalculation may produce a more accurate measurement of the minor offset of each leaf because controller 140 has corrected for the optical distortion of camera 220. In step 516, controller 140 may store the corrected minor offset values of the leaves in memory 142. In future sessions, controller 140 may receive the corrected minor offset values from the memory 142 and utilize them, for example, to control leaf placement during a radiotherapy session. The corrected minor offset values may remain accurate until a leaf of MLC 200 and/or an imaging marker 342 is replaced. In such an occasion, controller 140 may recalculate the minor offsets and store them in memory as the corrected minor offset values. Distortion coefficient k need not be recalculated when a leaf of MLC 200 or an imaging marker 342 is replaced because the optical characteristics of the camera lens remains unchanged. In step 518, controller 140 may control movement of the leaves utilizing the corrected leaf position coordinates and/or the corrected minor offset values. For example, controller 140 may advance a leaf to a desired position based upon the corrected position coordinates of that leaf. Because xundistorted and yundistorted are known for each leaf, controller 140 may accurately determine the distance to move each leaf to achieve a desired leaf position, without inadvertently over- or under-advancing the leaf. Additionally or alternatively, controller 140 may utilize the corrected minor offsets to accurately place the tip of each leaf based upon the detected marker position. Advantageously, controller 140 may place each leaf tip in a desired position, thus forming the correct shaping window for a radiotherapy beam. In some embodiments, controller 140 can control the MLC (step 518) prior to storing the corrected minor offsets in memory (step 516). FIG. 5C illustrates another exemplary calibration method 500B for a multi-leaf collimator, such as MLC 200. Method 500B may also be a processor-executed method. In some embodiments, method 500B may be executed by controller 140. In method 500B, controller 140 may execute steps 502-514 of method 500A. In step 515B, controller 140 may generate a leaf position error function for each leaf in MLC 200. A leaf position error function may characterize the optical distortion of each leaf in MLC 200 by the lens of camera 220; that is, a position error function may characterize the spatial relationship between the distorted and undistorted positions of the imaging marker of each collimator leaf. Referring to FIG. 10, in step 1002, controller 140 may identify at least two positions, in pixels, for the leaves. For example, controller 140 may identify a fully retracted and a fully extended position for each leaf. Alternatively, controller 140 may identify two or more alternative positions for each leaf. In step 1004, controller 140 may apply distortion to the identified positions for each leaf. The distortion may be based, at least in part, on the characteristics of the lens of camera 220. In step 1006, controller 140 may calculate the error, along a travel direction of the leaf, between the distorted and undistorted positions for each leaf. The travel directions of the leaves may be parallel to the x-axis in FIG. 5B, as the leaves of MLC 200 may only be configured for one-dimensional advancement and retraction in the x-direction. In step 1008, controller 140 may convert the calculated error from pixels into a unit of distance (e.g. millimeters or microns) using the predetermined conversion factor discussed above, which may be constant for all leaves of MLC 200. In step 1010, controller 140 may generate a position error function for each leaf by fitting a function to the converted error. In some embodiments, the position error function may be a third order polynomial function. The position error function for each leaf may receive the distorted x-coordinate of the imaging marker as input and may output the longitudinal distance between the distorted and undistorted x-coordinates of the imaging marker. In step 516B, controller 140 may store the corrected minor offset values and the position error function coefficients in memory 142. In future sessions, controller 140 may receive the corrected minor offset values and/or the position error function coefficients from the memory 142 and utilize them, for example, to control leaf placement during a radiotherapy session. The corrected minor offset values may remain accurate until a leaf of MLC 200 and/or an imaging marker 342 is replaced. In such an occasion, controller 140 may recalculate the minor offsets and store them in memory as the corrected minor offset values. The position error function coefficients may remain accurate until camera 220 and/or the camera lens is replaced, or when another component of the leaf-imaging configuration, such as light projector 240 or one of mirrors 222, 224, 242, or 244 is replaced. In step 518B, controller 140 may utilize the corrected minor offsets and position error functions to accurately determine the leaf positions and to control movement of the leaves. For example, controller 140 may receive imaging marker position data from camera 220 and may utilize the position error functions to determine the true positions of the imaging markers. Controller 140 may then use the corrected minor offset values to determine the positions of leaf tips 304 and may move the tips to desired beam-shaping positions. Advantageously, controller 140 may place each leaf tip in a desired position, thus forming the correct shaping window for a radiotherapy beam. Advantageously, the calibration methods of the present disclosure may accurately quantify and correct for the barrel distortion of camera 220 and the manufacturing inconsistencies of the minor offsets in a shorter period of time and with fewer computing steps than prior calibration methods. As a result, accurate control of the collimator leaf positions may be achieved while also reducing the length of time and the number of steps required to calibrate the MLC and to execute a radiotherapy session. This may be particularly beneficial to research hospitals and smaller clinics which may not have available time to perform radiation-based calibration. FIG. 11A illustrates an exemplary radiotherapy method 1100A. Method 1100A may be a processor-executed method. In some embodiments, the steps of method 1100A may be executed by the same processor, such as controller 140. Alternatively, one or more steps of method 1100A can be executed by separate processors. In step 1102, controller 140 may receive a radiotherapy treatment plan for treating a target tissue of a patient, such as a tumour. Controller 140 may receive the treatment plan from memory, such as memory 142. In some embodiments, controller 140 may have previously generated the radiotherapy treatment plan based upon, among other things, images of the target tissue, and may have stored the treatment plan in memory 142. In other embodiments, the radiotherapy treatment plan may be generated by a different processor and may be executed by controller 140. The radiotherapy treatment plan may include radiation dose and radiation beam shape, as well as other parameters such as beam angles, dose-histogram-volume information, the number of radiation beams to be used during radiotherapy, the dose per beam, and the like. Factors such as the location and size of the target tumour may be taken into consideration to achieve a balance between efficient treatment of the tumour (e.g., such that the tumour receives enough radiation dose for an effective therapy) and low irradiation of the healthy surrounding tissue (e.g., the healthy surrounding tissue receives as low a radiation dose as possible). One of ordinary skill in the art will appreciate that the radiotherapy treatment plan described herein is merely exemplary, and that any suitable radiotherapy treatment plan may be utilized according to the present disclosure. In step 1104, controller 140 may determine radiotherapy position coordinates for the tip of each leaf. The radiotherapy position coordinates may be determined relative to coordinate space 520 and may represent the leaf tip positions for shaping radiation beam 122 according to the received radiotherapy treatment plan. In step 1106, controller 140 may receive the corrected minor offset values for each leaf and a set of calibration coefficients, for example from memory 142. The calibration coefficients may be coefficients of polynomial functions which characterize the optical distortion for each leaf within a bank of leaves 310, 320. For each bank of leaves, the optical distortion may be characterized by three third-order polynomials; accordingly, controller 140 may receive 24 calibration coefficients (2 banks×3 polynomials per bank×4 coefficients per polynomial). The calibration coefficients may be generated from data received from a plurality of radiation heads, optionally including radiation head 104. All of the radiation heads may have the same model camera 220, the same type of camera lens, and the same leaf-imaging configuration (for example, the arrangement of light projector 240 and the mirrors 222, 224, 242, and 244 depicted in FIG. 2). Accordingly, the calibration coefficients may be representative of the optical distortion effects in all MLCs with the same model camera, camera lens, and leaf-imaging configuration. In some embodiments, controller 140 may generate the calibration coefficients; in some alternative embodiments, the calibration coefficients may be generated by a separate processor. The calibration coefficients may be generated in real-time, or may be generated before execution of method 1100A and accessed (e.g. from a memory) during execution of method 1100A. A processor (e.g. controller 140) may receive the data from the plurality of radiation heads and generate the lens centre, k value, and leaf position error functions for each head (e.g. according to method 500B). The processor may perform filtering to identify and remove outlier data. Such outlier data may be due to mechanical variation or tolerance; by removing the outliers, the processor may ensure that the remaining data is more representative of the camera lens and leaf-imaging configuration. The filtered data from the plurality of radiation heads may be averaged or otherwise combined to produce representative data, which the processor may fit with functions to produce the calibration coefficients. When data is received from an additional radiation head, or when a component of system 100 (e.g. the lens of camera 220) is altered or replaced, the processor may recalculate the calibration coefficients and store them (e.g. in memory 142). In step 1106, controller 140 may receive the calibration coefficients and in step 1108, controller 140 may use the calibration coefficients to generate three distortion-modeling functions for each bank of leaves (thus, six distortion modeling functions in total). In some embodiments, the distortion modeling functions may be third-order polynomial functions, each having four coefficients. Thus, controller 140 may receive 24 calibration coefficients in step 1106. The distortion-modeling functions may characterize the optical distortion of each leaf in the corresponding leaf bank; that is, the distortion-modeling functions may receive the number of a leaf within a bank (e.g. between 1 and 80) and may generate values that quantify the optical distortion associated with the given leaf. Advantageously, the distortion-modeling functions require far fewer coefficients than the leaf position error functions generated in step 1010: the former requires just 24 coefficients, while the later requires 480 coefficients. As a result, less memory is required to store the coefficients. In addition, the distortion modeling functions may quantify the optical distortion more accurately due to the removal of outliers during the filtering processes explained above. For a given bank of leaves (e.g. 310 or 320), controller 140 may generate the following distortion-modeling functions:ai=A1·i3−B1·i2+C1·i+D1 bi=A2·i3−B2·i2+C2·i+D2 ci=A3·i3−B3·i2+C3·i+D3 where i is the number of a leaf within the bank (e.g. with 1≤i≤80), A1-3, B1-3, C1-3, and D1-3 are the twelve calibration coefficients for the bank of leaves, and ai, bi, and ci are values which quantify the optical distortion for each leaf. Controller 140 may calculate ai, bi, and ci for each leaf in the bank of leaves by plugging in the leaf number i to the distortion modeling functions. In step 1110, controller 140 may generate a position error function for each leaf of MLC 200 using the calculated ai, bi, and ci values. Similar to the position error functions generated in step 1010, the position error functions generated in step 1110 may characterize the error in the determined imaging marker position caused by the optical distortion of the camera lens. For a given leaf i, controller 140 may generate a leaf position error function as follows:opticDeltai=ai·xdistorted3−bi·xdistorted+ci·xdistorted where opticDeltai quantifies the error in the determined imaging marker position along the x-axis caused by the optical distortion (in a unit of distance such as microns) and where xdistorted is the x-coordinate of the imaging marker (relative to coordinate space 520) as detected by camera 220. Controller 140 may generate a leaf position error function for each leaf in MLC 200, and may use the functions to generate an opticDeltai value for each leaf. The y-coordinates of the leaves may not require correction because each leaf may be fixed along the y-axis of coordinate space 520; thus, the y-position of each leaf is known at all times and need not be corrected. In step 1112, controller 140 may calculate the undistorted x-coordinate xundistorted of each leaf tip (in a unit of distance such as microns) as follows:xundistorted=xdistorted−xMO+opticDeltai where xMO is the minor offset of the leaf accessed from memory in step 1106. Thus, controller 140 may correct for the barrel distortion of the camera lens and the minor offset values, and may determine the true position of each leaf tip. In step 1114, controller 140 may advance and/or retract each leaf to its respective radiotherapy position coordinates. Because the true position of each leaf is known, controller 140 may accurately determine the distance to move each leaf to position it at the radiotherapy position coordinates, without over- or under-advancing the leaf. In step 1116, controller may control radiation head 104 to deliver radiation to the target tumour. Because the leaves of MLC 200 are accurately positioned, irradiation of healthy tissue may be minimized or eliminated while ensuring that the entire area of the target tumour is irradiated according to the radiotherapy treatment plan. FIG. 11B illustrates another exemplary radiotherapy method 1100B. Method 11008 may also be a processor-executed method. In some embodiments, the steps of method 1100B may be executed by the same processor, such as controller 140. Alternatively, one or more steps of method 1100B may be executed by separate processors. In method 1100B, controller 140 may execute steps 1102 and 1104 of method 1100A. In step 1106B, controller 140 may receive the corrected minor offset values of the leaves, as well as the coefficients of the leaf position error functions generated in step 1010. In step 1110B, controller 140 may regenerate the position error function for each leaf using the received coefficients. In step 1112, controller 140 may use the functions to calculate the opticDeltai value and the xundistorted value for each leaf. Controller 140 may execute steps 1114 and 1116 of method 1100A. Various operations or functions are described herein, which may be implemented or defined as software code or instructions. Such content may be directly executable (“object” or “executable” form), source code, or difference code (“delta” or “patch” code). Software implementations of the embodiments described herein may be provided via an article of manufacture with the code or instructions stored thereon, or via a method of operating a communication interface to send data via the communication interface. A machine- or computer-readable storage medium may cause a machine to perform the functions or operations described, and includes any mechanism that stores information in a form accessible by a machine (e.g., computing device, electronic system, and the like), such as recordable/non-recordable media (e.g., read only memory (ROM), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, and the like). A communication interface includes any mechanism that interfaces to any of a hardwired, wireless, optical, and the like, medium to communicate to another device, such as a memory bus interface, a processor bus interface, an Internet connection, a disk controller, and the like. The communication interface can be configured by providing configuration parameters and/or sending signals to prepare the communication interface to provide a data signal describing the software content. The communication interface can be accessed via one or more commands or signals sent to the communication interface. The present disclosure also relates to a system for performing the operations herein. This system may be specially constructed for the required purposes, or it may include a general-purpose computer selectively activated or reconfigured by a computer program stored in the computer. Such a computer program may be stored in a computer readable storage medium, such as, but not limited to, any type of disk including floppy disks, optical disks, CDROMs, and magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, or any type of media suitable for storing electronic instructions, each coupled to a computer system bus. The order of execution or performance of the operations in embodiments illustrated and described herein is not essential, unless otherwise specified. That is, the operations may be performed in any order, unless otherwise specified, and embodiments may include additional or fewer operations than those disclosed herein. For example, it is contemplated that executing or performing a particular operation before, contemporaneously with, or after another operation is within the scope of aspects of the invention. Embodiments may be implemented with computer-executable instructions. The computer-executable instructions may be organized into one or more computer-executable components or modules. Embodiments may be implemented with any number and organization of such components or modules. For example, aspects of the disclosure are not limited to the specific computer-executable instructions or the specific components or modules illustrated in the figures and described herein. Other embodiments may include different computer-executable instructions or components having more or less functionality than illustrated and described herein. When introducing elements of aspects of the disclosure or the embodiments thereof, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Having described aspects of the disclosure in detail, it will be apparent that modifications and variations are possible without departing from the scope of aspects of the disclosure as defined in the appended claims. As various changes could be made in the above constructions, products, and methods without departing from the scope of aspects of the disclosure, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. |
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claims | 1. A micro-manipulation method for manipulating a micro-object with a micro-handling tool under electron beam irradiation of an electron microscope, wherein said method comprises steps of: adjusting accelerating voltage of the electron beam, a first potential of the micro-handling tool and a second potential of a work substrate; and picking up and releasing the micro-object with the micro-handling tool. 2. A micro-manipulation method according to claim 1 , wherein said micro-object has a predetermined size, and the accelerating voltage of the electron beam is adjusted to make the electron beam penetrate the micro-object in the predetermined size. claim 1 3. A micro-manipulation method according to claim 1 or 2 , said method further comprises a step of: claim 1 2 preparing the work substrate by providing a conductive glass substrate and coating a polymer film on the conductive glass substrate, whereby the adhesion force between the micro-object and the substrate is increased. 4. A micro-manipulation method according to claim 1 or 2 , said method further comprises a step of: claim 1 2 preparing the work substrate by providing a glass substrate, evaporating an ITO film of a transparent conductive electrode on the glass substrate, and dip-coating a polystyrene film, whereby increasing an adhesion force between the micro-object and the work substrate. |
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description | This application is a Continuation of U.S. Ser. No. 12/077,016 filed Mar. 14, 2008; which application claims the benefit under 35 USC 119(e) of U.S. Provisional Application No. 60/918,540 filed Mar. 16, 2007, entitled “Radiation Treatment Planning And Delivery For Moving Targets In The Heart;” the full disclosures of which are incorporated herein by reference in their entirety. This application is related to U.S. patent Ser. No. 11/971,399 filed Jan. 9, 2008, entitled “Depositing Radiation In Heart Muscle Under Ultrasound Guidance;” U.S. patent Ser. No. 11/971,725 filed on Jan. 9, 2008, entitled “Method for Depositing Radiation in Heart Muscle;” and U.S. Provisional Application No. 60/975,373 filed on Sep. 26, 2007, entitled “Radiosurgical Ablation of the Myocardium;” the full disclosures of which are incorporated herein by reference in their entirety. The present invention generally provides improved methods, devices, and systems for treatment of tissue, in many cases by directing radiation from outside the body toward an internal target tissue. Exemplary embodiments may deposit a specified radiation dose at a target in the heart muscle while limiting or minimizing the dose received by adjoining radiation sensitive structures. In the past, targets such as tumors in the head, spine, abdomen and lungs have been successfully treated by using radiosurgery. During radiosurgery, the target is bombarded with a series of beams of ionizing radiation (for example, a series of MeV X-ray beams) fired from various different positions and orientations by a radiation delivery system. The beams can be directed through intermediate tissue toward the target tissue so as to affect the tumor biology. The beam trajectories help limit the radiation exposure to the intermediate and other collateral tissues, using the cumulative radiation dose at the target to treat the tumor. The CyberKnife™ Radiosurgical System (Accuray Inc.) and the Trilogy™ radiosurgical system (Varian Medical Systems) are two such radiation delivery systems. Modern robotic radiosurgical systems may incorporate imaging into the treatment system so as to verify the position of the target tissue without having to rely on rigid frameworks affixing the patient to a patient support. Some systems also have an ability to treat tissues that move during respiration, and this has significantly broadened the number of patients that can benefit from radiosurgery. It has also previously been proposed to make use of radiosurgical treatments for treatment of other tissues that undergo physiological movements, including the directing of radiation toward selected areas of the heart for treatment of atrial fibrillation. During atrial fibrillation, the atria lose their organized pumping action. In normal sinus rhythm, the atria contract, the valves open, and blood fills the ventricles (the lower chambers). The ventricles then contract to complete the organized cycle of each heart beat. Atrial fibrillation has been characterized as a storm of electrical energy that travels across the atria, causing these upper chambers of the heart to quiver or fibrillate. During atrial fibrillation, the blood is not able to empty efficiently from the atria into the ventricles with each heart beat. By directing ionizing radiation toward the heart based on lesion patterns used in open surgical atrial fibrillation therapies (such as the Maze procedure), the resulting scar tissue may prevent recirculating electrical signals and thereby diminish or eliminate the atrial fibrillation. While the proposed radiosurgical treatments of atrial fibrillation offer benefits by significantly reducing trauma for heart patients, improvements to existing radiosurgical systems may be helpful to expand the use of such therapies. For example, movement of the tissues of the heart during a heartbeat may be significantly more rapid than movements of lung tumors induced by respiration. While well suited for treatment of lung tissues and the like, existing systems used to verify target registration may also limit radiation exposure of collateral tissues and/or avoid delays in the procedure by limiting the rate at which x-ray images are acquired during treatment. As several radiation-sensitive structures are in and/or near the heart, and as the treatment time for a single heart patient may be as long as 30 minutes or more, increasing the imaging rate and/or delaying the radiation beams when the target tissue is not sufficiently aligned may be undesirable in many cases. In light of the above, it would be desirable to provide improved devices, systems, and methods for treating moving tissues of a patient, particularly by directing radiation from outside the patient and into target tissues of a heart. It would be particularly beneficial if these improvements were compatible with (and could be implemented by modification of) existing radiosurgical systems, ideally without significantly increasing the exposure of patients to incidental imaging radiation, without increasing the costs so much as to make these treatments unavailable to many patients, and/or without unnecessarily degrading the accuracy of the treatments and without causing collateral damage to the healthy tissue despite the movement of the target tissues during beating of the heart. The present invention generally provides improved medical devices, systems, and methods, particularly for radiation treatment planning and delivery for moving tissues in a heart. The invention allows improved radiosurgical treatment of tissues of the heart, often enhancing the capabilities of existing robotic radiosurgical systems for targeting tissues of the heart to mitigate arrhythmias such as atrial fibrillation or the like. In one embodiment, a method is disclosed for radiating a moving target inside a heart comprising acquiring sequential volumetric representations of an area of the heart and defining a target tissue region and/or a radiation sensitive structure region in 3-dimensions (3D) for a first of the representations. The target tissue region and/or radiation sensitive structure region are identified for another of the representations by an analysis of the area of the heart from the first representation and the other representation. Radiation beams to the target tissue region are fired in response to the identified target tissue region and/or radiation sensitive structure region from the other representation. In another embodiment, a method is disclosed for radiating a moving target of a wall of a heart comprising acquiring at least one volume of the heart and defining the target tissue region and/or critical structure region in 3D so that the target tissue region extends through the wall of the heart. A dose distribution is computed and radiation beams are fired to the target to obtain the simulated dose distribution transmurally through the wall of the heart. In another embodiment, a method is disclosed for radiating a moving target inside a heart comprising acquiring a computed tomography (CT) volume and defining a transmural target tissue region. A dose distribution is computed and visualized using volume or surface rendering in 3D so as to verify transmurality. In another embodiment, a system is disclosed for radiating a moving target inside a heart comprising a volume acquisition system for acquiring at least one CT volume of an area of the heart and a processor coupled to the image acquisition system. The processor is configured for defining the target tissue region and/or critical structure region in 3D and computing a dose distribution. A robot is coupled to the processor and a radiation beam source is supported by the robot and is coupled to the processor. The processor controls the firing of a series of the radiation beams from the radiation source so as to treat the target tissue region. In another embodiment, a system is disclosed for radiating a moving target inside a heart comprising a volume acquisition system for acquiring a computed tomography (CT) volume and a processor coupled to the image acquisition system. the processor is configured for defining a transmural target tissue region and computing a dose distribution. A visualization system is used for visualizing the dose distribution using volume or surface rendering in 3-dimensions (3D) so as to verify transmurality. Many different types of modeling may be used with the method and systems, including (1) volume rendering, (2) maximum intensity projection, (3) minimum intensity projection, (4) X-ray projection, (5) haptic feedback, (6). virtual fly-through, (7) stereoscopic 3D rendering, (8) virtual reality and (9) multi-planar, oblique and curved reconstruction. In some embodiments the contours of the target tissue region and/or a radiation sensitive structure region are outlined in 3D. In some embodiments an electrogram may be registered to the CT volumes. In some embodiments the moving target is a wall of a heart and the methods and systems ensure transmurality of the target. The present invention generally provides improved devices, systems, and methods for treatment of tissue, often using radiosurgical systems. The invention is particularly well suited for tracking of moving tissues such as tissues of the heart and tissue structures adjacent the heart that move with the cardiac or heartbeat cycles. Alternatively, it is also suited for tracking of moving tissues in the heart and its adjacent structures due to respiration. The invention may take advantage of structures and methods which have been developed for treating tumors, particularly those which are associated with treatments of tissue structures that move with the respiration cycle. A variety of differing embodiments may be employed, with the following description presenting exemplary embodiments that do not necessarily limit the scope of the invention. Radiosurgery is a known method of treating targets in the body, such as tumors in the head, spine, abdomen and lungs. During radiosurgery, the target is bombarded with a series of MeV X-ray beams fired from various different positions and orientations by using a radiation delivery system, to affect the tumor biology using the cumulative radiation dose at the target. The radiation can be delivered invasively in conjunction with traditional scalpel surgery, or through a percutaneous catheter. Radiation can also be delivered non-invasively from outside the body, through overlying tissue. CyberKnife™ (Accuray Inc.) and Trilogy™ (Varian Medical Systems) are two such radiation delivery systems. Advances in stereotactic surgery have provided increased accuracy in registering the position of tissue targeted for treatment and a radiation source. For example, see U.S. Pat. Nos. 6,351,662 and 6,402,762. Stereotactic radiosurgery systems may be commercially available from ACCURAY, INC. of Sunnyvale, Calif., and BRAINLAB. The Accuray Cyberknife™ stereotactic radiosurgery system has reportedly been used to provide targeted, painless, and fast treatment of tumors. Improvements in imaging and computer technology have led to advances in radiation treatment, often for targeting tumors of the spine and brain. The introduction of CT scanners enables surgeons and radiation oncologist to better define the location and shape of a tumor. Further improvements in imaging technology include MRI, ultrasound, fluoroscopy and PET scanners. In addition, radiation therapy has also been aided by enhancements in ancillary technologies such as simulators to help position patients and advanced computers to improve treatment planning to enable the radiation oncologist to deliver radiation from a number of different angles. Computer technology has been introduced that enable radiation oncologists to link CT scanners to radiation therapy, making treatment more precise and treatment planning faster and more accurate, thereby making more complex plans available. Such advancements allow integrated conformal therapy, in which the radiation beam conforms to an actual shape of a tumor to minimize collateral damage to the surrounding healthy tissue. By combining simulators and imaging and treatment planning computers, the irradiation can be precisely administered. The present invention may take advantage of many components included in or derived from known radiation delivery system components. Suitable system components may comprise: 1. A linear accelerator (Linac) capable of generating the X-ray beam. 2. A mechanism to position and orient the X-ray beam. 3. A patient registration system to position and orient the target in the coordinate system of the delivery system. 4. A tracking system for tracking the target during treatment in case the target changes shape or moves between the time of, for example, a CT exam and the time of treatment, and/or during treatment. 5. A couch capable of positioning the target (patient) independent of the mechanism described in #2 above. In exemplary CyberKnife-based systems, the above 5 items may correspond to: 1. A 6 MeV X-band X-ray Linac 2. A 6 degree-of-freedom (DOF) robotic manipulator. 3. A patient registration system consisting of: Two ceiling-mounted diagnostic X-ray sources Two amorphous silicon image detectors mounted on the floor. 4. During treatment, two orthogonal X-rays are taken and registered with the CT data by cross-correlating the X-rays with simulated X-rays generated by CT data, called digitally reconstructed radiographs (DRR). 5. The tracking system may include several light-emitting diodes (LEDs) mounted on the patent's skin to provide additional information at a rate faster than what X-rays alone may provide. 6. A couch with 5 DOF. An exemplary Cyberknife stereotactic radiosurgery system 10 is illustrated in FIG. 1. Radiosurgery system 10 has a single source of radiation, which moves about relative to a patient. Radiosurgery system 10 includes a lightweight linear accelerator 12 mounted to a highly maneuverable robotic arm 14. An image guidance system 16 uses image registration techniques to determine the treatment site coordinates with respect to linear accelerator 12, and transmits the target coordinates to robot arm 14 which then directs a radiation beam to the treatment site. When the target moves, system 10 detects the change and corrects the beam pointing in real-time or near real-time. Real-time or near real-time image guidance may avoid any need for skeletal fixation to rigidly immobilize the target. System 10 makes use of robot arm 14 and linear accelerator 12 under computer control. Image guidance system 16 includes diagnostic x-ray source 18 and image detectors 20, this imaging hardware comprising two fixed diagnostics fluoroscopes. These fluoroscopes provide a stationary frame of reference for locating the patient's anatomy, which, in turn, has a known relationship to the reference frame of robot arm 14 and linear accelerator 12. Image guidance system 16 can monitor patient movement and automatically adjust system 10 to maintain the radiation beam directed at the selected target tissue. Rather than make use of radiosurgery system 10 and related externally applied radiosurgical techniques to tumors of the spine and brain tissues, the invention applies system 10 to numerous cardiac conditions, and in one exemplary method to the treatment of atrial fibrillation (AF). Tradition radiosurgery instruments without image guidance technology rely on stereotactic metal frames screwed into the patient's skull to accurately target a tumor. Traditional radiosurgery has its drawbacks, the biggest of which relate to the use of the frame, including the pain and difficulty of accurately reattaching the frame in precisely the same location, along with the inability to target tissues other than those in the neck and head. Conventional linear accelerators for these systems can also be the size and weight of an automobile. Frame-based radiosurgery is generally limited to isocentric or spherical target treatments. To allow a device which can precisely pinpoint and treat tissues throughout the body, system 10 makes use of a portable linear accelerator, such as those originally designed for industrial inspections, which can be carried on a person's back. Linear accelerators may be commercially available from SCHONBERG RESEARCH GROUP, SIEMENS, PICKER INTERNATIONAL INC. or VARIAN. System 10 allows intensity modulated radiation therapy. Using computerized planning and delivery, intensity modulated radiation therapy conforms the radiation to the shape of (for example) a tumor. By using computers to analyze the treatment planning options, multiple beams of radiation match the shape of the tumor. To allow radiosurgery, system 10 can apply intense doses of high-energy radiation to destroy tissue in a single treatment. Radiosurgery with system 10 uses precise spatial localization and large numbers of cross-fired radiation beams. Because of the high dosage of radiation being administered, such radiosurgery is generally more precise than other radiation treatments, with targeting accuracies of 1 to 2 mm. Linear accelerator 12 is robotically controlled and delivers pin-point radiation to target regions throughout the body of the patient. Radiation may be administered by using a portable linear accelerator such as that illustrated in FIG. 1. Larger linear accelerators may also generate the radiation in some embodiments. Such linear accelerators may be mounted on a large rotating arm that travels around the patient, delivering radiation in constant arcs. This process delivers radiation to the target tissue and also irradiates a certain amount of surrounding tissue. As a result, such radiation therapy may be administered in a series of relatively small doses given daily over a period of several weeks, a process referred to as fractionation. Each radiation dose can create some collateral damage to the healthy surrounding tissue. In the exemplary embodiment, robot arm 14 of system 10 is part of a pure robotics system, providing six degree of freedom range of motion. In use, the surgeon basically pushes a button and the non-invasive procedure is performed automatically with the image guidance system continuously checking and re-checking the position of the target tissue and the precision with which linear accelerator 12 is firing radiation at the tumor. Image guidance system provides ultrasound guidance that gives the surgeon the position of internal organs. Image guidance system continuously checks, during a procedure, that the radiation beam is directed to the target. Alternatively the image guidance system includes an X-ray imaging system as is the case with the traditional Accuray CyberKnife™ radiosurgery system. The exemplary image guidance system takes the surgeon's hand out of the loop. The surgeon may not even be in the operating room with the patient. Instead, the image guidance system guides the procedure automatically on a real-time basis. By combining advanced image guidance and robotics, system 10 has proven effective in treating head and neck tumors without having to resort to stereotactic metal frame screwed into the skull of a patient. The target shape may be a three-dimensional shape and may include (1) volume rendering, (2) maximum intensity projection, (3) minimum intensity projection, (4) X-ray projection, (5) haptic feedback, (6). virtual fly-through, (7) stereoscopic 3D rendering, (8) virtual reality, and (9) multi-planar, oblique and curved reconstruction. The system 10 creates the target shape to encompass (including or surrounding) the anatomical site. The anatomical site may include an ostium of a pulmonary vein (PV), a cavotricuspid isthmus (CTI), an Atrioventricular (AV) node or junction, Sinoatrial (SA) node, His-Purkinje fibers, or ablation of areas necessary to control and treat aberrant arrhythmias, an atrial or ventricular site, neural fibers near or adjacent to the heart (ganglionic) or neural fibers in the chest or neck. Once the target position is determined, the coordinates are relayed to robot arm 14, which adjusts the pointing of linear accelerator 12 and radiation is delivered. The speed of the imaging process allows the system to detect and adjust to changes in target position in less than one second. The linear accelerator is then moved to a new position and the process is repeated. Alternative systems may make use of laser triangulation, which refers to a method of using so-called laser tattoos to mark external points on the skin's surface so as to target the location of internal organs and critical structures. An alternative system commercialized by BRAINLAB uses a slightly different approach that measures chest wall movements. The system is capable of directing one or more doses of radiation from outside of the patient's body toward the target shape to ablate the target shape. The quantity of absorbed in a tissue is the “dose” with the SI unit Gray (Gy=J/kg). The dose is strongly dependent on the type of radiation and the time span, also called “dwell time”. An application dose rate is the dose of radiation per time (delivered or received). The dose rate delivered by a source depends on the activity of the source and the radionuclide that it contains. Biological effects of the absorbed radiation are dependent on the type of radiation and the type of tissue which is irradiated. Both total radiation dose and dose rate are important, since damage caused by radiation can be repaired between fractionated doses or during low dose rate exposure. The target dose rate may be between 15 to 80 Gy, preferably, between 25 to 40 Gy to achieve histological change at the target site without harm to other tissue. In one embodiment, the accuracy of is better than 2 mm, which is within the range of cardiac motion certain portions of the heart at or within 2 mm plus or minus. System 10 combines robotics and advanced image-guidance to deliver true frameless radiosurgery. Multiple beams of image guided radiation are delivered by robot arm 14 mounted linear accelerator 12. The radiation can converge upon a tumor, destroying it while minimizing exposure to surrounding healthy tissue. Elimination of a stereotactic frame through the use of image guided robotics enables system 10 to treat targets located throughout the body, not just in the head. Radiosurgery is thus possible in areas such as the spine that have traditionally been difficult to treat in the past with radiosurgery, and for pediatric patients such as infants, whose skulls are too thin and fragile to undergo frame-based treatment. System 10 allows ablation of tissue anywhere in the patient's body. The present invention uses high energy x-ray irradiation from a linear accelerator mounted on a robot arm to produce ablation of target tissue. In one example, system 10 is used to ablate tumors or other defects of the heart treatable with radiation. Advantages of system 10 include a treatment which can be provided on an outpatient basis, providing a painless option without the risk of complications associated with open surgery. Treatment may be applied in a single-fraction or hypo-fractionated radiosurgery (usually 2 to 5 fractions) for treatment near sensitive structures. System 10 provides flexibility in approach through computer control of flexible robotic arm 14 for access to hard-to-reach locations. System 10 is capable of irradiating with millimeter accuracy. System 10 also has the ability to comprehensively treat multiple target shapes. System 10 allows isocentric (for spherical) or non-isocentric (for irregularly shaped) target shapes. The creation of the target shapes also takes into account critical surrounding structures, and through the use of robotic arm 14, harm to the critical structures surrounding may be reduced. Sophisticated software allows for complex radiation dose planning in which critical structures are identified and protected from harmful levels of radiation dose. After careful planning, the precise robotic arm can stretch to hard-to-reach areas. The precise radiation delivered from the arm then minimizes the chance of injury to critical surrounding structures, with near-real-time image-guidance system eliminating the need for rigid immobilization, allowing robot arm 12 to track the body throughout the treatment. It may be advantageous to, for a moving target inside the heart: 1. Proscribe a dose distribution to a target region in moving tissue, 2. Simulate the dose distribution, and 3. Deliver the specified dose. During treatment planning for system 10, beam nodes 30 and weights may be selected by a computer programming module to: 1. Deliver the proscribed dose to a target 32. 2. Avoid or minimize the dose delivered to radiation sensitive structures 34, such as shown in FIG. 2. Before a treatment session, a CT volume of the target vicinity is acquired. Other imaging modalities such as MRI, PET and ultrasound may also be used. The user defines the target and any radiation sensitive structures by outlining a series of contours in slices through the CT volume. A computer program then generates the set of nodes 30 from which a set of beams 36 will be fired and the weights for each of the beams. Alternatively, the user selects the nodes and the computer program generates the weights. If the target is inside the heart, a series of CT volumes, called a volumetric movie may be acquired to capture the motion of the target. The definition of the target and the radiation sensitive structures can be time consuming since the user may outline contours in each of the volumes in the volumetric movie. The volumetric movie may be acquired as a function of a physiologic waveform such as EKG, respiratory signal or both. In the case where the target is inside the heart on heart muscle, radiosurgical ablation creates scar tissue and eliminates abnormally conducting tissue. Radiosurgical ablation thus has the ability to suppress arrhythmias by creating lesions at targets such as the cavotricuspid isthmus and pulmonary vein ostia. One of key objectives when defining the target on heart muscle is to ensure that the target is transmural, i.e., covers the entire thickness of the heart muscle. The methods for defining targets in the body using CT involves the user drawing 2-dimensional contours in axial, sagittal, coronal or oblique slices generated from the CT volume. Since heart is a complex 3-dimensional shape, it is not easy to draw such contours on heart muscle in above mentioned slices to ensure that target transmurality is achieved. Embodiments of the invention eliminates this limitation by allowing target definition in 3-dimensions, and providing techniques to visualize the target on heart muscle to ensure that the target is in fact transmural. In an exemplary new method, the user defines the target and the radiation sensitive structures much more quickly. The steps of this embodiment method may include the following: 1. Acquire a series of M CT volumes, CT(j), j=0, . . . , M−1, of the heart over one cardiac cycle with the patient holding his/her breath. Use a high speed CT scanner such as 64-slice Siemens SOMOTOM Definition to acquire CT volumes quickly, e.g. one volume in 83 ms. Contrast agents may be used. FIG. 3 shows a typical EKG waveform with M=10 phases where 10 CT volumes are acquired. Alternatively, the CT volumes, CT(j) could be acquired over a respiratory cycle. Additionally, the CT volumes, CT(j) may be acquired over a respiratory cycle, yet triggered to an EKG cycle. 2. Load all the M CT data volumes (here in forth known as “volumetric movie”) in to a data visualization computer software application module running on the processor of system 10 coupled to a suitable display device, or on a processor capable of communicating to the processor of system 10. FIG. 4 shows a screenshot of a display of an exemplary such application. Top-left, bottom-left, bottom-right views, called multi-planar reconstruction-views (or MPR views), are axial, sagittal and coronal slices through a single volume in the volumetric movie, respectively. Top right is a view, called volume rendered view (or VR view), containing a 3D representation of the volume, generated using a technique called volume rendering. The VR view also covers techniques of generating other 3D representations such as (a) maximum intensity projection, (b) minimum intensity projection and (c) X-ray projection. 3. Define the target region and radiation sensitive structures in 3D using, for example, the VR-view. The user optionally drags and drops a geometric-shape, such as a doughnut, at the target region, such as the ostia of a pulmonary vein. The application provides 3D tools to orient and place the doughnut in the correct place and orientation. The application may also provide alternative MPR-views, such as a view orthogonal to the viewing direction, oblique reconstructed views, and curved reconstructed views. 4. Additionally, surface detection techniques such as “marching cubes” can be used to detect the 3-dimensional surfaces corresponding to the borders of myocardial tissue. Using the tools provided, the user can edit these surfaces to define the target. Editing includes cutting a surfaces, clipping using a bounding box. FIGS. 5(a), 5(b) and 5(c) show the target shape to be defined in the case of PV ostia to ensure transmurality. FIG. 5(a) shows the anatomy including the left atrium 40 and pulmonary vein 42. FIG. 5(c) shows the target shape 44, a hollow cylinder-like shape. This ensures that the area ablated covers the full thickness of the walls of the PV ostium. The user can define this shape in 3-dimensions using the techniques described above. If they were to define this target in 2-dimensional slices, it would be very difficult. Alternatively, the user can define a target such as the cylinder-shape 46 shown in FIG. 5(b), which encompasses the PV ostium and the blood inside it as well. This shape, called Planning Target Volume for Optimization (PTVO) can be used by the treatment planning software to generate the node-set. To quantify the dose delivered to the tissue, Planning Target Volume for Evaluation (PTVE), as shown in FIG. 5(c) can be used. In this case both PTVO and PTVE must be defined by the user to ensure transmurality. PTVO can also be automatically generated from PTVE. If an electrogram is available, it can be registered to the CT data set and shown to the user. The user then sees the areas where the electrical activity is abnormal in the electrogram and can define the target in the electrogram it self in 3-dimensions. Since the CT is registered to the electrogram, this target can then be used to define PTVE or PTVO. Alternatively, the user can define the target in CT and visualize it in the electrogram in 3-dimensions to ensure that the target in fact covers areas where the electrical activity is high. 5. Other types of target shapes, such as spheres and polyhedrons can be used. Other types of target regions, such as, cavotricuspid isthmus or AV node can be used. Alternatively, the target and critical structure shapes can be defined using a 3D mouse or a 3D bumper tool, an improvement over the 2D mouse and 2D bumper tool found in MultiPlan™ Treatment Planning Workstation (Accuray Incorporated). 6. Optionally, the application provides the ability to view the target area from inside the heart chambers and vessels using a technique called “virtual-fly though”. An airplane rudder control-like interface provides the ability for the user to visualize the myocardial walls from within the heart. The user gets the sensation that he/she is flying inside the heart chambers. Using various controls, they can bank, accelerate, decelerate, pull-up, nose-down inside the heart chambers. The user can also place the doughnut-shaped target, or any other-shaped target, at pulmonary vein ostia or any other area inside the heart. 7. Optionally, the application also provides force feedback to the user. Instead or in addition to a computer mouse, the user can use a haptic feedback device such as Omega Haptic Device (Force Dimension, Inc.). When the user grabs the target and moves it towards the target region, if the geometric shape is inside the blood, he/she will feel very little resistance to movement. If the geometric shape impinges the heart wall, he/she will feel some resistance, possibly the sensation of pushing against soft-tissue, or a rubber-like material. 8. Optionally, the application may provide a stereoscopic 3D rendering to the user. In stereoscopic 3D rendering the VR-view is generated twice using two different vantage points, typically separated by the average distance between human eyes. These left and right images are then shown to the left and right eyes of the user separately simultaneously or in rapid sequence. There are a number of display devices to view stereoscopic 3D renderings: a. Stereo goggles using polarizing lenses or switching displays. b. Stereoscopic monitors 9. The system loads the other CT volumes from the volumetric movie. It then automatically finds the location of the soft tissue region covered by the aforementioned geometric shape in all the volumes. Following this, it finds the motion of the soft tissue region throughout the cardiac cycle by using all the volumes. Correlation of a similarity function, based on CT intensities, higher order derivatives thereof, or features can be used to find the motion. One exemplary method and/or system (here employing mutual information as a similarity measure) that may be suitable for use in embodiments of the invention (without limiting other embodiments that may use other approaches) is described in an article by L. Zollei, E. Crimson, A. Norbash, W. Wells, entitled “2D-3D rigid registration of x-ray fluoroscopy and CT images using mutual information and sparsely sampled histogram estimators,” CVPR 2001, which is incorporated herein by reference. Another exemplary method and/or system can be found in the deformable registration method described by J-P Thirion entitled “Image Matching as a diffusion process: an analogy with Maxwell's Demons”, Medical Image Analysis (1998) Volume 2, Number 3, pp 243-260, Oxford University Press. 10A. The system then computes the dose distributions for each of the volumes in the volumetric movie. From this, it computes the average dose distribution. 10B. Alternatively, the motion of the target or critical structures that cannot be tracked can be accounted for by expanding the target and critical volumes with a margin that is based on motion estimates. The margin can be large enough to include the full amplitude of motion or it could be large enough to include the target a large percentage of the time. Expanding the target region by the full extent of the motion will result in more tissue destruction than is necessary. In radiosurgical treatment of tumors, margins have the benefit of destroying any microscopic extension of the cancer that is not visible in the images. However, in radiosurgical treatment of arrhythmias, the target structure is well known and does not include any extension, therefore, the margin should be minimized. Margins can be calculated to include the target a large percentage of the time by determining the three dimensional probability density function for the target position and then setting the margin to include some fraction of the integrated probability. The dose calculation can then be modified based on the fraction of the treatment when the target is within the volume. Multiple margins calculated with different probability levels can be used in the dose calculation. For example, if a margin is drawn around a target region to include the complete target 80% of the time, the minimum dose can be estimated as 0.8*min80, where min80 represents the minimum dose within the margin that includes the entire target 80% of the time. In this estimate, target is considered to receive no dose during the time it spends outside of the margin. If an additional margin is drawn to include the target region 95% of the time, the minimum dose can be estimated as the lesser of (min80) and (0.8*min80+0.15*min95), where min80 is defined as above and min90 represents the minimum dose within the margin that includes the entire target 95% of the time. These calculations will underestimate the minimum dose to the target less than using a margin that includes the target 100% of the time. Similar calculations can be made for the maximum dose to critical structures. For example, if a margin is drawn to include the complete critical structure 80% of the time, the maximum dose to any point in the critical structure can be calculated as (0.8*max80 +0.2*maxField), where max80 is the maximum dose within the margin that includes the target 80% of the time and maxField represents the maximum dose in the field. If an additional margin is drawn to include the critical structure 100% of the time, the maximum dose to any point in the critical structure can be calculated as the greater of max80 and (0.8*max80+0.2*max100), where max80 is defined as above and max100 is the maximum dose within the margin that includes the critical structure 100% of the time. This will overestimate the maximum dose to the critical structure less than a margin based on including the critical structure 100% of the time. Isotropic or anisotropic margins can be used to account for the motion. Anisotropic margins can be calculated by moving each surface point in an outward surface normal direction by a distance equal to the radius of a margin ellipsoid in the same direction as the outward surface normal. Accuracy may be improved by defining the margin ellipsoid such that its principle axes are aligned with the principle axis of the motion of the target or critical structure. Margin estimates do not require full volumetric motion information from the target. An estimate of the target motion can be determined by the position measurements for one point on the target at multiple times during the cardiac cycle. This can be obtained from simultaneous biplanar fluoroscopic images showing the tip of a catheter that has been placed in the heart touching the cardiac structure of interest. Alternatively, real-time 3D ultrasound could be used to determine the motion of structures of interest non-invasively. 11. The robot then fires the beams from predetermined locations to create the simulated dose distribution. 12. Alternatively, the user may visualize the 3D or 4D dose distributions using a volume rendering of the dose distribution. Optionally, 3D fly though and haptic feedback can be used to visualize and interact with the 3D or 4D dose distributions. Referring now to FIG. 6, a relatively simple treatment flowchart 50 can represent imaging 52, planning 54, and treatment 56 steps and/or structures used before and during radiosurgical treatment according to embodiments of the present invention. Imaging 52, planning 54, and treatment 56 structures may include an associated processor module. The processor modules will typically comprise computer processing hardware and/or software, with the software typically being in the form of tangible media embodying computer-readable instructions or code for implementing one, some, or all of the method steps described herein. Suitable tangible media may comprise a random access memory (RAM), a read-only memory (ROM), a volatile memory, a non-volatile memory, a flash memory, a magnetic recording media (such as a hard disk, a floppy disk, or the like), an optical recording media (such as a compact disk (CD), a digital video disk (DVD), a read-only compact disk, a read/write compact disk, a memory stick, or the like). The various modules described herein may be implemented in a single processor board of a single general purpose computer, or may be run on several different processor boards of multiple proprietary computers, with the code, data, and signals being transmitted between the processor boards using a bus, a network (such as an Ethernet, intranet, or internet), via tangible recording media, using wireless telemetry, or the like. The code may be written as a monolithic software program, but will typically comprise a variety of separate subroutines and/or programs handling differing functions in any of a wide variety of software architectures, data processing arrangements, and the like. Nonetheless, breaking the functionality of the program into separate modules is useful for understanding the capabilities of the various aspects of the invention. Addressing the imaging block 52 of block diagram 50 in FIG. 6, a time-sequence of 3-D volumes may be acquired using computed tomography (CT), magnetic resonance imaging (MRI), ultrasound imaging, X-ray imaging, optical coherence tomography, a combination of these or other imaging modalities, and/or the like. In some embodiments, corresponding EKG signals may also be received by the image processor module, and the processor may optionally use the EKG signals to time the acquisition of the 3-D volumes. In other embodiments, the respiratory signal may also be received by the image processor module, and the processor may optionally use the respiratory signal to time the acquisition of the 3D volumes. CT volumes may be acquired using a variety of different approaches. A cardiac gated CT volume may be acquired at a particular phase of the EKG cycle. Two variations of cardiac gated CT may include a held-breath version and a free-breathing version. In the held-breath cardiac gated CT, the patient is holding their breath (typically either at full inspiration or full expiration), so that respiration motion is absent while the data is acquired. In the free breathing cardiac gated CT, the patient is breathing freely. The CT volume may be acquired at a desired point of the respiration cycle. By measuring the respiration wave form, the exact respiratory phase at which the CT volume is acquired can be known (similar to the known cardiac phase at which the CT volume is acquired). In either variation, both the cardiac phase and the respiration cycle phase can be identified for the cardiac gated CT. A cardiac gated 4-dimensional CT can be generated by acquiring a time series of cardiac gated CT volumes at a series of desired EKG phases. Once again, the 4-D cardiac gated CT can be a held-breath type or a free-breathing type (as described above). Additionally, regarding the free-breathing cardiac gated 4D CT, the resulting series of CT volumes may be acquired at the same EKG phase, typically throughout the respiration cycle. By associating each CT volume with the associated phase of the respiration cycle, the time series CT volumes can be used to model respiratory-induced motion of tissue while minimizing the cardiac motion artifacts. Yet another type of volume which may be acquired is the respiratory-gated CT volume. Such CT volumes may be acquired at a particular phase of the respiration cycle. Respiratory gating of CT may be performed prospectively or retrospectively. The cardiac motion may generally be ignored in this type of CT volume, so that the rapidly moving cardiac structures may be blurry in such CT volumes. In a related respiratory-gated 4-D CT volume, a series of respiratory-gated CT volumes are acquired at a series of respiratory phases. Note that the tissue structure which will be targeted need not necessarily be visible in the image, so long as sufficiently contrasting surrogate imagable structures are visible in the images to identify the target tissue location. The imaging used in many embodiments will include a time sequence of three dimensional tissue volumes, with the time sequence typically spanning one or more cycles (such as a cardiac or heartbeat cycle, a respiration or breathing cycle, and/or the like). The series of radiation beams are planned, typically by a surgeon using a user interface (such as a display and keyboard, mouse, or other input device) to communicate with a plan processor module. Based on the images, a plan 54 will be prepared for treatment of the target tissue, with the plan typically comprising a series of radiation beam trajectories which intersect within the target tissue. The processor module may make use of the model (including the tissue movements) to determine dosages in the target, collateral, and critical or sensitive tissues. The radiation dose within the target tissue should be at least sufficient to provide the desired effect (often comprising ablation of tissue, inhibition of contractile pathways within the heart, inhibition of arrhythmogenesis, and/or the like). Radiation dosages outside the target tissues will decrease with a relatively steep gradient so as to inhibit damage to collateral tissues, with radiation dosages in specified sensitive and/or critical tissue structures often being below a desired maximum threshold to avoid deleterious side effects. Embodiments of the invention may employ the 3-D volumes acquired in the imaging step 52 during the planning 54, with exemplary embodiments making use of the motion model represented by the time sequence of 3-D tissue volumes so as to more accurately identify exposure of radiation outside of the target, within sensitive tissue structures, inside the target, and the like. Planned timing of some or all of a series of radiation beams may be established based on the cardiac cycle, the respiration cycle, and/or the like so as to generate the desired dosages within the target tissue, so as to minimize or inhibit radiation exposure to critical structures, and/or to provide desired gradients between the target tissue and collateral or sensitive structures. In some embodiments, the order of the planned radiation beams may be altered and/or the trajectories of the radiation beams may be calculated in response to the motion of the model volume. Once the plan 54 is established, the treatment 56 can be implemented. The treatment will often make use of a processor to direct movement of a robotic structure supporting a radiation beam source, along with registration, validation, and/or tracking modules which enhance accuracy of the treatment. Tracking may employ the motion model developed during imaging 52, and/or may also employ a separate intra-operative motion model. Alternatively, no motion model will be used, instead the target location computed from real-time image data will be used for tracking The treatment 56 step and the associated hardware may use a sensor and/or input for physiological wave forms such as the respiration phase, cardiac phase, and the like for use in such tracking. In one embodiment, an EKG sensor may be coupled to the patient to provide EKG signals to a targeting processor module. The targeting module configures the robot so as to position and orient the linear accelerator (or other radiation source) toward the target tissue along the desired trajectory for a particular radiation beam from among the series. Once the moving target tissue and the beam trajectory are appropriately aligned, the tracking module may fire the radiation beam by energizing the linear accelerator. Hence, the tracking module benefits from the motion model developed during the imaging steps, and the model may optionally be revised using data obtained immediately before and/or during treatment. Advantageously, the treatments described herein can be iterative. Rather than target many foci or regions as is often done in an invasive procedure, externally applied radiosurgical ablation can address one or more target shapes on one day, and the then other target shapes on another day as needed. The interim period between treatments can be used to access the need for subsequent treatments. Such iterative or fractionated treatment is thus more conservative than current methods. Suitable types of radiation, including particle beam radiation, may be employed. For example, the present invention encompasses the use of a GammaKnife™ radiosurgery system to ablate the moving tissue. Although gamma radiation could be administered during open heart or other invasive procedures, the currently preferred applications are substantially non-surgical. While the exemplary embodiments have been described in some detail, by way of example and for clarity of understanding, those of skill in the art will recognize that a variety of modification, adaptations, and changes may be employed. Hence, the scope of the present invention should be limited solely by the appending claims. |
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052727408 | summary | TECHNICAL FIELD The present invention concerns an agent for trapping the radioactivity of fission products which appear in a nuclear reactor fuel element in the course of combustion, that agent comprising a stable oxygenated compound of the fission products. Such a trapping agent is in particular adapted to long-life radioactive fission products such as Cs, Sr . . . which are generated in the course of irradiation in a nuclear reactor. STATE OF THE ART Reactors of the PWR, BWR or fast neutron type which use fuel pellets based on sintered oxide UO.sub.2 or mixed oxides generate `in situ` fission products of which some are not specifically gaseous in the core of the reactor. In normal operation those solid fission products remain generally in place in the pellets although in regard to some thereof migration phenomena may occur, which are due to the temperature differences between the core and the periphery of a pellet, towards the outside of the pellet. Even in that case however the major part thereof remains confined in the fuel pellets. The fission products appear in the pellets in elementary form and may form compounds, which are relatively stable at the temperature of the core of the reactor (300.degree. to 900.degree. C.), with the nuclear fuel oxides which form the pellets. However, in the case of a major accident which causes an excessive rise in temperature in the core of the reactor, followed by damage to or even fusion of the core, such compounds are insufficiently stable and the fission products are then liberated, with serious risk of dissemination into and contamination of the environment; that risk is more especially severe as such fission products have long lives (some tens of years). That is the case for example with Cs 137 and Sr 90. An arrangement which makes it possible to trap caesium in normal operation in a fast neutron reactor has been proposed in patent FR 2438319 (Westinghouse); it comprises interposing between the fissile and fertile fuel elements Cs captors which are formed by pellets of low density and particular shape and which consist of TiO.sub.2 or Nb.sub.2 O.sub.5. Those oxides fix Cs at the usual temperature in the core of the reactor and the shape of the pellets makes it possible to avoid any stress, due to swelling which occurs in the course of normal operation of the reactor, on the sheathing of the fuel element. In that arrangement, it appears that the caesium has to reach the pellets of captors in order to be trapped and that only Cs which has migrated to a sufficient degree is actually trapped. In the event of a major accident such an arrangement would be found to be insufficiently effective to prevent all dissemination of the Cs; in fact, all the free Cs which has not yet been trapped but which is present in the fuel pellets could escape from the sheathing and contaminate the environment, as the trapping speed is not fast enough. In addition compounds such as CsNbO.sub.3 or Cs.sub.2 Ti.sub.2 O.sub.5 formed in the trapping operation seem to be of insufficient stability at very high temperature (for example above 1600.degree. C.). That is why the applicants sought a way of trapping the dangerous fission products, as far as possible as soon as they appear in the course of irradiation, in particular in the mass of the fuel pellets. The applicants also sought a trap which is sufficiently stable and effective so that the fission products are not removed again at elevated temperatures (which can attain or exceed 1600.degree. C. or in the event of core fusion or melt-down) and which is in any case more stable than the compounds which are formed in situ between uranium oxide and the fission products (for example Cs). The applicants also sought to provide a trap which does not give rise to fusion or premature incipient fusion of the fuel pellets in the event of a major accident, in other words a trap which does not perform a fusioning function in relation to the pellets which will thus retain adequate refractoriness. |
abstract | A method for optimizing alignment performance in a fleet of exposure systems involves characterizing each exposure system in a fleet of exposure systems to generate a set of distinctive distortion profiles associated with each exposure system. The set of distinctive distortion profiles are stored in a database. A wafer having reference pattern formed thereon is provided for further pattern fabrication and an exposure system is selected from the fleet to fabricate a next layer on the wafer. Linear and higher order parameters of the selected exposure system are adjusted using the distinctive distortion profiles to model the distortion of the reference pattern. Once the exposure system is adjusted, it is used to form a lithographic pattern on the wafer. |
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description | Embodiments of the steam turbine control device of the nuclear power plant concerning this invention are explained below. Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views. FIG. 1 is a block flow diagram showing a first embodiment of the present invention. In this embodiment, a steam turbine control device 19 has a control means to restrain a fall of the main steam pressure, ie., the pressure of the main steam header 4 or the main steam system 61, when the main steam isolation valves 2 are closed. A changeover means changes over, as a pressure control signal, from the reactor dome pressure control signal side to the main steam pressure control signal side when the main steam isolation valves 2 are closed. A second pressure deviation calculating unit 31 calculates with the main steam pressure signal 35 from the main steam pressure detector 26 installed in the main steam header 4 or the main steam system (main steam line) 61 as shown in FIG. 8 and the signal from a main steam pressure setter 30. A main steam pressure control calculating unit 32 calculates the pressure deviation signal from the second pressure deviation calculating unit 31 and outputs the main steam pressure control signal 37. A main steam isolation valve fully closed position detector 34 detects that the main steam isolation valve 2 that isolates the main steam system from the nuclear reactor 1 is fully closed. A pressure control signal changeover unit 33 changes over the pressure control signal 29 from the reactor dome pressure control signal 36 to the main steam pressure control signal 37 when the main steam isolation valves 2 are fully closed. That is, when the pressure control signal changeover unit 33 receives the pressure control change trigger signal 38 from the main steam isolation valve fully closed position detector 34, the connection state of the pressure control signal changeover unit 33 is changed over from between a-c to between b-c, and then the signal outputted as the pressure control signal 29 from the pressure control signal changeover unit 33 is changed over from the reactor dome pressure control signal 36 to the main steam pressure control signal 37. Since some of the physical structure in this embodiment may be similar to the conventional structure shown in FIG. 9, the same reference characters are given to the same composition. FIGS. 2a-2c are signal time charts for explaining the function and effect of the first embodiment acquired by constituting as shown in FIG. 1 mentioned above. FIG. 2a shows a signal time chart of the rector dome pressure and the main steam pressure. As shown in FIG. 2a, if the main steam isolation valves 2 are fully closed and the pressure control signal 29 is changed over to the main steam pressure control signal 37 by the pressure control signal changeover unit 33, the main steam pressure detected by the main steam pressure detector 26 below the main steam isolation valves 2 falls according to the loss of steam supply, so the main steam pressure control signal 37 calculated by the main steam pressure control calculating unit 32 using the deviation signal between the main steam pressure signal and the signal from the main steam pressure setter 30 becomes zero or less. Therefore, the pressure control signal 29 denotes fully closed position command, that is, the main steam control valve 6 and the turbine by-pass valve 7 are thus closed. At this time, the steam flow into the steam turbine 8 or the condenser 10 is lost, and a rapid reduction of the steam that remains in the main steam system 61 downstream of the main steam isolation valves 2 can be prevented, as shown in FIG. 2a. Therefore, the steam remaining in the main steam system 61 is supplied to the turbine gland steam evaporator 12 as its heating steam, and a fall in the amount of supply of the gland sealing steam from the turbine gland steam evaporator 12 to the steam turbine 8 can be restrained. Moreover, in this embodiment, a rapid reduction of the drive steam of the steam jet air ejector 14 is prevented, and the vacuum drop in the condenser 10 can be restrained in an action like an atomizer by the steam flow into the steam jet air ejector 14. Consequently, the concept of this embodiment can be applied easily to any plant, even if it is an established conventional plant, without troubles concerned to the fully closed position of the main steam isolation valves 2. In addition, FIG. 2b shows a signal time chart of the reactor dome pressure control signal 36 and the main steam pressure control signal 37, and FIG. 2c shows a signal time chart of the pressure control signal 29 that determines the position of the main steam control valve 6. FIG. 3 is a block flow diagram showing a second embodiment of the present invention In this embodiment, the steam turbine control device as mentioned in the first embodiment shown in FIG. 1 has an additional control means to restrain the abrupt change at the time of the changeover of a pressure control signal from the main steam pressure control signal 37 to the reactor dome pressure control signal 36 when the signal of the main steam isolation valve fully closed position detector 34 is cancelled. In the steam turbine control device, a pressure control deviation calculating unit 43 calculates the deviation between the reactor dome pressure control signal 36 and the pressure control signal 29. A NOT circuit (logic reversal circuit) 39 outputs a signal when the pressure control change trigger signal 38 from the main steam isolation valve fully closed position detector 34 is in a OFF state. A one-shot circuit 40 outputs a signal in an instant when an output arises from the NOT circuit 39. A relay contact 42 closes in an instant when the signal from the one-shot circuit 40 is outputted, and a bias signal generator 41, in the case that a signal is inputted, outputs a signal whose initial value is the value of the inputted signal and that decreases by a certain rate of change. The signal from the bias signal generator 41 is inputted to the first pressure deviation calculating unit 24 as an additive signal, and then the output of the first pressure deviation calculating unit 24 becomes the deviation signal added a bias. In this embodiment, the abrupt change of the pressure control signal 29 may be restrained when the pressure control signal 29 returns to the reactor dome pressure control signal 36 by the pressure control signal changeover unit 33. FIGS. 4a-4b are signal time charts for explaining the function and effect of the second embodiment. The ordinate axis shows pressure and the abscissa axis shows time. FIG. 4a is a signal time chart of the reactor dome pressure and the main steam pressure for explaining the function and effect of the second embodiment of this invention described in FIG. 3. FIG. 4b is a chart of the reactor dome pressure and the main steam pressure in the first embodiment of this invention described in FIG. 1. In the second embodiment, once the pressure control change trigger signal 38 does not exist after the main steam isolation valves 2 are refully closed, the pressure control signal 29 changes over from the main steam pressure control signal 37 to the reactor dome pressure control signal 36 by the pressure control signal changeover unit 33. If there is non-zero deviation between the main steam pressure control signal 37 and the reactor dome pressure control signal 36 at this time, the pressure control signal 29 changes abruptly according to the deviation, and the reactor dome pressure can be changed as shown in FIG. 4b according to the first embodiment of this invention. To the contrary, according to the second embodiment as shown in FIG. 3, the pressure control signal 29 can change over stably and restrain the change of the reactor dome pressure as shown in FIG. 4a, by adding the deviation between the pressure control signal 29 and the reactor dome pressure control signal 36 as bias to the reactor dome pressure control signal 36 side and by decreasing the bias by a certain rate of changeover gradually. FIG. 5 is a block flow diagram showing a third embodiment of the present invention. In this embodiment, the steam turbine control device in the above-mentioned embodiments, as shown in FIG. 1 or FIG. 3, further comprises a holding means for holding the pressure control change trigger signal 38 by the signal of the main steam isolation valve fully closed position detector 34 and a canceling means for canceling the pressure control change trigger signal 38 by manual operation or the signal of the main steam isolation valve fully open position detector 48. In the third embodiment, the main steam control device further comprises a self-holding means 46 to hold the pressure control trigger signal 38 which is once in an ON state, having a first NOT circuit (logic reverse unit) 39, an OR circuit 44, and an AND circuit 45. A manual reset operation unit 47 outputs a signal to the AND circuit 45 of the self-holding means 46 so that the self-holding state of the self-holding means 46 can be canceled This situation as mentioned above shows an example in this embodiment where the main steam isolation valve fully position state detector 48, that detects the fully open position of the main steam isolation valves 2, is not included. In the third embodiment described above, it is possible to hold the state that the pressure control change trigger signal 38 is in an ON state and the pressure control signal 29 is changed over to the main steam pressure control signal 37, and it is also possible to cancel the pressure control change trigger signal 38 by the manual reset operation unit 47. So it is enabled to change over the pressure control signal 29 to the reactor dome pressure control signal 36 side manually according to the judgment of the operating staff. We may, in the third embodiment shown in FIG. 5, transpose the manual reset operation unit 47 for the series circuit of the main steam isolation value fully open position detector 48 and a second NOT circuit 55, to cancel the self-holding means 46. In the third embodiment described above, it is possible to hold the state that the pressure control change trigger signal 38 is in an ON state and the pressure control signal 29 is changed over to the main steam pressure control signal 37, and it is also possible to cancel the pressure control change trigger signal 38 when the main steam isolation valves 2 are fully opened. The pressure control signal 29 can be changed over to the reactor dome pressure control signal 36 side automatically when the main steam isolation valves 2 are detected to be fully open. FIG. 6 is a block flow diagram showing a fourth embodiment of the present invention. In this embodiment, in the steam turbine control device as mentioned in the third embodiment shown in FIG. 5, the manual reset operation unit 47 is substituted for a series circuit of a pressure switch 49 and a NOT circuit 39 to cancel the signal of self-holding means 46. The pressure switch 49 is activated when a pressure signal input is less than and equal to a pressure setting xcex1, wherein xcex1 is a fixed value that is enough to be decompressed, for example, 1 MPa. The pressure switch 49 detects the reactor dome pressure signal 28 is not more than a fixed value xcex1. A canceling means cancels the pressure control change trigger signal 38 when the reactor dome pressure falls to be equal to and less than a enough to be decompressed. In this embodiment, it is possible to hold the state that the pressure control change trigger signal 38 is in an ON state and the pressure control signal 29 is changed over to the main steam pressure control signal 37. After that, the nuclear reactor 1 is to be decompressed for a shutdown operation of the nuclear reactor 1. It is thus possible to cancel the pressure control change trigger signal 38 when the decompression operation of the nuclear reactor 1 is detected to be finished, and then the pressure control signal 29 can be changed over to the reactor dome pressure control signal 36 automatically with a shutdown operation of the nuclear reactor 1. FIG. 7 is a block flow diagram showing a fifth embodiment of the present invention. In this embodiment, the steam turbine pressure detectors 26 in the steam turbine control device in the first or second embodiment shown in FIG. 1 or FIG. 3 are multiple, two or three. Specifically, in this embodiment, two main steam pressure detectors 26 and the second medium value selector 50 are added to the construction of the above-mentioned embodiments, and the main steam pressure signal 35 is replaced by the signal of medium value selected by the second medium value selector 50 from the triplex main steam pressure detectors 26. In this embodiment, even when the main steam isolation valves 2 are fully closed and one system breaks down among three systems of the main steam pressure detectors 26, the main steam pressure signal 35 is normally outputted to the second pressure deviation calculating unit 31. In the fifth embodiment, three sets of the main steam pressure detectors 26 may be replaced by two sets of the main steam pressure detectors 26, and the second medium value selector 50 may be replaced by a high value selector 51 (not shown) which chooses the high value of the outputs of the two main steam pressure detectors 26. In this case, the main steam pressure signal 35 is replaced by the signal of the higher value chosen by the high value selector 51 among the signals from the doubled main steam pressure detectors 26. In this structure, even when the main steam isolation valves 2 are fully closed and one system breaks down between two systems of the main steam pressure detectors 26, a fall in the main steam pressure signal 35 can be restrained. This invention is not limited to these embodiments described above. For example, a state indicator may display the changeover state of the contact of the pressure control signal changeover unit 33 in the first or second embodiments shown in FIG. 1 or FIG. 3. This structure enables an operating staff to recognize the changeover state of the pressure control signal 29 easily. With the form of the embodiments described above, the means to restrain the fall in the main steam pressure when the main steam isolation valves 2 are closed is constructed by the means to change over the pressure control signal 29 from the reactor dome pressure control signal 36 to the main steam pressure control signal 37 For example, the pressure control signal changeover unit 33 can be replaced by a control means to control the main steam control valve 6 and/or the turbine by-pass valve 7 shown in FIG. 8 when the main steam isolation valves 2 are fully closed. Furthermore, in the third embodiment shown in FIG. 5, the inputs of the self-holding means 46 have two signals of the main steam isolation valve fully closed position detector 34 and one of the manual reset operation unit 47 and the main steam isolation valve fully open position detector 48, which can be replaced by the three signals of the main steam isolation valve fully closed position detector 34, the manual reset operation unit 47, and the main steam isolation valve fully open position detector 48. And the input of the AND circuit 45 in the third embodiment shown in FIG. 5 may further comprise the input of a series circuit of the NOT circuit 39 and the pressure switch 49 described in the fourth embodiment shown in FIG. 6. In this case, the reactor pressure signal 28 may be inputted to the other end of the series circuit of the NOT circuit 39 and the pressure switch 49. Moreover, although the third, fourth, and fifth embodiments shown in FIGS. 5, 6, and 7 explain the case where the first embodiment shown in FIG. 1 is used as a base, which can similarly explain the case where the second embodiment shown in FIG. 3 is used as a base. Furthermore, at least one of the speed/load control calculating unit 15, the load limiter 16, the maximum discharge restriction unit 17, the first and second low value selectors 18 and 22, the first and second deviation calculating units 20 and 21, the reactor dome pressure setter 23, the first and second pressure deviation calculating units 24 and 31, the reactor dome pressure control calculating unit 25, the first and second medium value selectors 27 and 50, the main steam pressure setter 30, the main steam pressure control calculating unit 32, the pressure control signal change unit 33, the first and second NOT circuits 39 and 55, the one-shot circuit 40, the bias signal generator 41, the relay contact 42, the pressure control deviation calculating unit 43, the OR circuit 44, the AND circuit 45, the manual reset operation unit 47, the pressure switch 49 activated when the pressure of its input signal is less than and equal to xcex1, the high value selector 51, may be hardware or a stored program memory and a CPU (central processing unit) which can read the content of the memory and calculate, or means similar to these. The first and the second indicator are hardware; the means for displaying the state, the memory storing the state signal, the software program, and the CPU reading and processing the content of the memory; or means similar to these. In the fifth embodiment shown in FIG. 7, the main steam pressure detectors 26 are doubled or tripled, but they may be multiple more than three. While there has been particularly shown and described with reference to the preferred embodiment thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details can be made therein without departing from the spirit and scope of the present invention. According to the present invention, since the main steam control valve and the turbine by-pass valve are fully closed when the main steam isolation valves are fully closed, it can be prevented to decrease abruptly the mass of the drive steam of the turbine grand steam evaporator, reactor feed water pump turbine, and the steam jet air ejector. The steam turbine control device of the nuclear power plant concerning this invention realizes to utilize the steam that remains in the main steam system effectively. |
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abstract | Systems and methods are disclosed for producing customized, predictable and reproducible supplies of radioisotopes using, for example, a reactor housing that is fabricated from a radioactive shielding material and has both an internal volume and a surface that comprises an entry port and an exit port, a chromatographic column that is positioned within said internal volume such that a first end of said column is in fluid communication with said entry port and a second end of said column is in fluid communication with said exit port, and a changeable filter module that is disposed external to said reactor housing and in fluid communication with said exit port. |
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052672751 | summary | BACKGROUND OF THE INVENTION The present invention is directed to the establishment of a leak tight or leak limiting joint between a base surface and a mating end surface of a hollow body. More particularly, the invention involves establishing effective seals on inclined and/or non-planar surfaces where a non-uniform or asymmetric preload force is applied to a compression gasket. Typical of the use of such a joint would be in connection with nuclear steam supply systems for power generation. In boiling water nuclear reactors, control rods are driven upwardly through "nozzles" disposed in the lower portion of the reactor pressure vessel. The nozzles are supported by and are longer than "stub tubes" which are welded to the interior wall of the reactor vessel. Each nozzle is sealed to its associated stub tube by means of an annular weld between the nozzle and the stub tube upper end. As fully described and illustrated in U.S. Pat. No. 4,826,217, leaks or leak paths may develop during the operation of a boiling water reactor. The apparatus for sealing the leaks illustrated in that patent includes an outer housing or hollow body which surrounds the stub tube/nozzle tube assembly and is generally coaxial therewith. A lower gasket means in the form of a packing ring is disposed between the hollow body at its end which mates with the reactor vessel and the vessel wall, which can be termed a base surface. The hollow body surrounds the leak or leak path to be sealed and the gasket means has a preload force applied by torquing a sealing nut against a spring washer at the top of the housing until sufficient pressure is provided to insure a good seal under vessel low pressure conditions. Reactor internal pressure generates a downward, i.e., a seating force on the lower gasket means, through the hollow body during reactor operation. Because the base surface is an inclined and/or a nonplanar surface, an asymmetrical loading results from the action of the reactor coolant on the sleeve housing and the housing or hollow body has a tendency to slide upwardly along the inclined vessel wall or base surface. Such sliding movement could result in the loss of sealing at the joint between the base surface and the mating end surface of the hollow body. SUMMARY OF THE INVENTION The present invention overcomes the above-discussed and other deficiencies of the prior art by providing an improved apparatus for effectively sealing a gasketed joint between a base surface and a mating end surface of a hollow body sealing device such as the outer housing of an apparatus for sealing leaks or leak paths between a reactor vessel cavity having an inclined or non-planar surface and the interior of a stub tube/nozzle tube assembly. The gasketed joint is effectively sealed by means of an asymmetric preloading force creating means in the form of a ring-shape which applies the created force to the hollow body end opposite said seal in an effective force loading pattern substantially in register with said gasket means. The ring-shaped asymmetric preloading force creating means has a radial structure such that the effective force loading pattern creates an asymmetric preload force on said gasket means. The radial structure is created by slots cut transversely to the direction of the preloading force and open to the periphery of the ring-shaped means to render some areas in register with the gasket means of a different spring constant than other such areas. The leak path to be sealed typically is between a reactor cavity having an inclined or non-planar surface and the interior of a stub tube/nozzle tube assembly and is surrounded by the hollow body. The base surface typically is inclined and the hollow body has a vertical axis. The base surface may also be of a non-planar shape such as is defined by a concave spherical surface portion of the inside of a reactor vessel bottom. |
abstract | An upper hole 37A and a lower hole 37B are provided at two positions, namely, upper and lower portions, of a side surface of a guide tube 27, and a thimble tube 22 is pressed against an inner circumferential surface of the guide tube 27, by a differential pressure between coolant inside and outside the upper hole 37A and the lower hole 37B. It is preferable that an upper pressure adjustment hole and a lower pressure adjustment hole are provided at two positions, namely, upper and lower portions, of a side surface of an upper core support column 21, and a coolant flowing into the guide tube from an upper end of the guide tube flows out to the outside from inside the guide tube through a gap between the thimble tube and the upper hole, and also flows out to the outside from inside the upper core support column through the upper pressure adjustment hole, and a coolant flowing into the guide tube from a lower end of the guide tube flows out to the outside from inside the guide tube through a gap between the thimble tube and the lower hole, and also flows out to the outside from inside the upper core support column through the lower pressure adjustment hole. |
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claims | 1. An x-ray optical system comprising:an x-ray source which emits x-rays;a first optical element which conditions the x-rays to form two collimated beams; andat least a second optical element which further conditions a first beam of the two beams from the first optical element, the first beam conditioned by the first and the second optical elements being directed at a desired location in a first operation mode and a second beam of the two beams conditioned by the first optical element being directed at the desired location in a second operation mode wherein the second optical element is a channel-cut crystal monochromator which conditions the first beam of the two beams from the first optical element, the first beam conditioned by the channel-cut monochromator having a beam path after the monochromator that is aligned with the beam path of the second beam from the first optical element. 2. The system of claim 1 wherein the channel-cut monochromator includes two reflecting surfaces with two different atomic planes. 3. The system of claim 1 wherein the channel-cut monochromator includes two reflecting surfaces with the same atomic planes. 4. The system of claim 1 further comprising a third optical element, the channel-cut monchromator being positioned between the first optical element and the third optical element, the third optical element further conditioning the first beam from the channel-cut monochromator. 5. The system of claim 4 wherein the third optical element is a parabolic reflector focusing the first beam conditioned by the channel-cut monochromator. 6. The system of claim 4 wherein the channel-cut monochromator is rotatable by about 180 degrees about an axis, so that either the first beam conditioned by the first optical element and the second optical element reaches the desired location or the second beam conditioned by the first optical element, the second optical element and the third optical element reaches the desired location. 7. The system of claim 1 wherein the channel-cut monochromator is rotatable by about 90 degrees about an axis, so that either the first beam conditioned by the first optical element and the second optical element reaches the desired location or the second beam conditioned by the first optical element reaches the desired location. |
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abstract | In an X-ray diffraction method using the parallel beam method, an X-ray parallel beam is incident on a sample, and diffracted X-rays from the sample are reflected at a mirror and thereafter detected by an X-ray detector. The reflective surface of the mirror has a shape of an equiangular spiral that has a center located on the surface of the sample. A crystal lattice plane that causes reflection is parallel to the reflective surface at any point on the reflective surface. The X-ray detector is one-dimensional position sensitive in a plane parallel to the diffraction plane. A relative positional relationship between the mirror and the X-ray detector is determined so that reflected X-rays from different points on the reflective surface of the mirror reach different points on the X-ray detector respectively. This X-ray diffraction method is superior in angular resolution, and is small in X-ray intensity reduction, and is simple in structure. |
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description | The present application hereby claims priority under 35 U.S.C. §119 to German patent application number DE 10 2011 103 264.2 filed May 26, 2011, the entire contents of which are hereby incorporated herein by reference. At least one embodiment of the invention generally relates to a grid module of a scattered-radiation grid, to a scattered-radiation grid including a number of grid modules with webs arranged next to one another, especially for use in conjunction with a CT detector, to a CT detector and/or to a CT system with such a detector. Scattered-radiation grids—more precisely scattered-radiation collimators embodied in a grid shape—for CT detectors are generally known and are used in almost every CT system currently employed in practice. Such scattered-radiation grids are of importance in particular in dual-source CT systems with two emitter/detector systems offset at an angle to each other on the gantry, since the amount of scattered radiation from an emitter system operated in parallel and offset at an angle is especially high. In relation to a scattered-radiation grid of modular construction the reader is referred to German publication DE 10 2008 030 893 A1 for example. One problem with such modular scattered-radiation grids with a number of grid modules arranged next to one another however lies in the fact that artifacts occur in the area of the joint between two grid modules in the projections recorded therewith, which have a negative effect on the image quality of a tomographic image dataset reconstructed from such projections or generate visible artifacts in the tomographic image respectively. An embodiment of the invention is directed to a modular scattered-radiation grid in which projection artifacts are largely suppressed. Advantageous developments of the invention are the subject matter of subordinate claims. In accordance with this basic idea, the inventors propose, in at least one embodiment, a grid module for a scattered-radiation grid comprising a number of grid modules disposed next to one another with webs, with the height of each web disposed at least on an edge side in the respective grid module being lower than the height of webs disposed further inwards in the grid module. In at least one embodiment, a detector of a CT system is disclosed with a modular construction scattered-radiation grid. In at least one embodiment, a CT system with a detector with modular construction scattered-radiation grid is disclosed. Various example embodiments will now be described more fully with reference to the accompanying drawings in which only some example embodiments are shown. Specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments. The present invention, however, may be embodied in many alternate forms and should not be construed as limited to only the example embodiments set forth herein. Accordingly, while example embodiments of the invention are capable of various modifications and alternative forms, embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit example embodiments of the present invention to the particular forms disclosed. On the contrary, example embodiments are to cover all modifications, equivalents, and alternatives falling within the scope of the invention. Like numbers refer to like elements throughout the description of the figures. Before discussing example embodiments in more detail, it is noted that some example embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the operations as sequential processes, many of the operations may be performed in parallel, concurrently or simultaneously. In addition, the order of operations may be re-arranged. The processes may be terminated when their operations are completed, but may also have additional steps not included in the figure. The processes may correspond to methods, functions, procedures, subroutines, subprograms, etc. Methods discussed below, some of which are illustrated by the flow charts, may be implemented by hardware, software, firmware, middleware, microcode, hardware description languages, or any combination thereof. When implemented in software, firmware, middleware or microcode, the program code or code segments to perform the necessary tasks will be stored in a machine or computer readable medium such as a storage medium or non-transitory computer readable medium. A processor(s) will perform the necessary tasks. Specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments of the present invention. This invention may, however, be embodied in many alternate forms and should not be construed as limited to only the embodiments set forth herein. It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments of the present invention. As used herein, the term “and/or,” includes any and all combinations of one or more of the associated listed items. It will be understood that when an element is referred to as being “connected,” or “coupled,” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected,” or “directly coupled,” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between,” versus “directly between,” “adjacent,” versus “directly adjacent,” etc.). The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments of the invention. As used herein, the singular forms “a,” “an,” and “the,” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the terms “and/or” and “at least one of” include any and all combinations of one or more of the associated listed items. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may in fact be executed substantially concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Portions of the example embodiments and corresponding detailed description may be presented in terms of software, or algorithms and symbolic representations of operation on data bits within a computer memory. These descriptions and representations are the ones by which those of ordinary skill in the art effectively convey the substance of their work to others of ordinary skill in the art. An algorithm, as the term is used here, and as it is used generally, is conceived to be a self-consistent sequence of steps leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of optical, electrical, or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like. In the following description, illustrative embodiments may be described with reference to acts and symbolic representations of operations (e.g., in the form of flowcharts) that may be implemented as program modules or functional processes include routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types and may be implemented using existing hardware at existing network elements. Such existing hardware may include one or more Central Processing Units (CPUs), digital signal processors (DSPs), application-specific-integrated-circuits, field programmable gate arrays (FPGAs) computers or the like. Note also that the software implemented aspects of the example embodiments may be typically encoded on some form of program storage medium or implemented over some type of transmission medium. The program storage medium (e.g., non-transitory storage medium) may be magnetic (e.g., a floppy disk or a hard drive) or optical (e.g., a compact disk read only memory, or “CD ROM”), and may be read only or random access. Similarly, the transmission medium may be twisted wire pairs, coaxial cable, optical fiber, or some other suitable transmission medium known to the art. The example embodiments not limited by these aspects of any given implementation. It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise, or as is apparent from the discussion, terms such as “processing” or “computing” or “calculating” or “determining” of “displaying” or the like, refer to the action and processes of a computer system, or similar electronic computing device/hardware, that manipulates and transforms data represented as physical, electronic quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices. Spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper”, and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, term such as “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein are interpreted accordingly. Although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, it should be understood that these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or section from another region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of the present invention. The inventors have recognized that the artifacts in the area of the joints of grid modules of a modular-design scattered-radiation grid essentially arise as a result of a wall thickening of the grid webs occurring in these joint areas because of the doubled walls in these areas and, through this, scattered radiation arriving from the side—in relation to the other, non-doubled walls—being more heavily suppressed. Basically, although a greater suppression of scattered radiation would be advantageous, an increased scattered radiation suppression only locally at specific points generates undesired artifacts. In order to avoid this excessive suppression, it would basically be possible to halve the wall thicknesses of the webs of the grids at the joints of the grid modules, so that ultimately, at the joint between two webs, the same, i.e. single, web thickness occurs as at all other webs of the scattered-radiation grid. However such a measure would greatly increase the production costs. As an alternative a web could also be left out on one side of the module in each case with the same effect, however partly-free and unsupported web ends would then occur, which would be easily damaged during assembly or would lead to increased installation and checking expense. The inventors thus propose, in at least one embodiment, to reduce the height of the grid webs abutting each other and thus forming thicker grid webs such that the increased shielding of the scattered radiation by the construction-related thickening of the overall web width is simply compensated for by the lower height of the at least thickened grid web. Since this causes the sum of the unshielded scattered radiation to again correspond to the value without thickening of the grid web, the artifact which arises as a result of a disproportionately high scattered-radiation shielding at the joints between two grid modules is avoided by this measure. Use is thus made of the fact that a reduced height of the webs of a scattered-radiation grid increasingly allows scattered radiation to pass through to the detector module lying below it and by this measure the disproportionate shielding of scattered radiation is simply compensated for by thicker webs so that the detector elements at the joints between the grid modules are also shielded with the same effectiveness as detector elements arranged centrally in relation to the grid module. Since the basic assumption is to be made that the shielding effect of a thickened grid web not only relates to the detector element in the immediate vicinity or to the adjacent row or column of detector elements, but also to detector pixels of the next and next-but-one row or column, the attenuation affect extending to these rows or columns can thus likewise be compensated for in an improved embodiment by an, albeit smaller, reduction of the height of the next grid web lying further inwards in the grid module. In accordance with this basic idea, the inventors propose, in at least one embodiment, a grid module for a scattered-radiation grid comprising a number of grid modules disposed next to one another with webs, with the height of each web disposed at least on an edge side in the respective grid module being lower than the height of webs disposed further inwards in the grid module. It is advantageous in this case for the heights in the at least one grid module of at least one further web to be embodied, inwards from the at least one edge-side low web, in steps of increasing height. Accordingly a scattered-radiation grid for an x-ray detector of a CT system with a plurality of detector elements arranged in columns and rows on the surface is also proposed, which has at least: At least two grid modules disposed next to one another, With each grid module possessing a number of grid webs disposed next to one another with irradiation zones lying between them, and At least one edge-side web of a grid module being adjacent and running in parallel to the at least one other edge-side web of another grid module with no irradiation zone disposed between them, With webs running adjacent to one another having a lower height than the other webs. In this case the lower height of the webs running adjacent to one another can be dimensioned so that the proportion of scattered radiation additionally absorbed by the webs running adjacent to one another is compensated for by the reduced height of the webs. It can be advantageous with such a scattered-radiation grid for at least one further web disposed further inwards in relation to the grid module to have a height which lies between the height of the webs disposed further inwards and a web disposed further outwards. In this case the lower height of the webs lying further inwards—in relation to the maximum height of the webs lying centrally—can be dimensioned such that the proportion of scattered radiation absorbed additionally by the webs running adjacent to one another is compensated for by the reduced height of the webs. Inventively the scattered-radiation grid can be constructed so that webs arranged exclusively in parallel to one another are provided. Mostly such webs run at right angles to the system axis of a CT system, mostly a CT-Systems with a single emitter/detector system. As an alternative to this, in an improved embodiment, the scattered-radiation grid can also be embodied so that the webs cross each other at right angles. A further improvement in scattered radiation reduction is achieved by this. With CT systems in particular with two emitter-detector systems offset at an angle on the gantry, in which the scattered radiation of the other emitter in each case generates especially intensive scattered radiation, such an embodiment is advantageous. Furthermore with such crossing webs the web heights at the crossing points should be identical where possible, so that it is proposed that the height of at least one web crossing with other webs reduces in stages at the ends. As part of an embodiment of the invention, a detector of a CT system with an inventive scattered-radiation grid of modular construction and also a CT system with such a detector are proposed. FIG. 1 shows a schematic diagram of an embodiment of an inventive CT system 1. The CT system 1 has a first emitter/detector system with an x-ray tube 2 and a detector 3 lying opposite it and a second emitter/detector system disposed offset at an angle on the gantry not shown explicitly here, with a second x-ray tube 4 with a detector 5 opposite it. The gantry is located in a gantry housing 6 and rotates the emitter/detector systems during the scanning around a system axis 9. The patient 7 to be examined is located on a movable examination table 8, which is either pushed continuously or sequentially along the system axis 9 through the scanning field located in the gantry housing 6, with the attenuation of the x-ray radiation emitted by the x-ray tubes being measured by the detectors. The operation of the CT system 1 is controlled with the aid of a control and processing system 10, which features computer programs Prg1 through Prgn which execute the control routines necessary for operation, carry out data editing and also perform the reconstruction of image datasets. The two emitter/detector systems of at least one embodiment feature inventive scattered-radiation grids of modular construction which screen out the scattered radiation occurring during operation and, as exclusively as possible are intended to let the radiation emitted directly from the x-ray tubes of the respective emitter/detector system, after its attenuation by the patient, strike the detector elements of the detector. Because of the simultaneous operation of the two x-ray tubes 2 and 4 it is particularly necessary to screen out scattered radiation occurring during the operation of the tubes 2 and 4. Scattered-radiation grids can especially be used for this purpose, which have webs crossing one another, as are shown in the subsequent figures. It is however also pointed out that scattered-radiation grids with webs running exclusively in parallel fall within the scope of the invention. An example of a detector 3 constructed from a plurality of detector elements D disposed next to one another like a checkerboard, with a scattered-radiation grid G lying above them comprising a plurality of webs S, is shown in longitudinal section in FIG. 2. FIG. 3 shows a known grid module GM with a number of grid webs S crossing each other at right angles in a 3D view obliquely from above. To avoid possible confusion of terms, in FIG. 4, which shows an individual grid web S in a 3D view, the length l, the height h and the depth d are entered in the diagram. FIG. 5 shows two grid modules GM disposed next to one another in an overhead view, with the webs S of grid modules GM doubling at the joint line L (when viewed three-dimensionally: joint surface) and thus adding to each other in relation to their overall effective depth. These two grid modules GM are shown again in FIG. 6 in section I-I. Here too it can be recognized that the total thickness of the web material at the joints doubles, by which scattered incident radiation is increasingly absorbed. Thus adjacent detector elements are especially heavily shielded from scattered radiation and this produces image artifacts. An inventive structure of an embodiment of grid modules or of a scattered-radiation grid of modular construction is shown in an overhead view in FIG. 7. Shown here are two adjacent grid modules GM—comprising a plurality of grid modules disposed next to one another—of a scattered-radiation grid of an x-ray detector. The grid modules GM are joined together—in a similar way to the embodiments in FIGS. 5 and 6—at a joint line L, with this resulting in a doubling of the effective wall thickness because the overall wall thickness of the webs remains the same in the area of the joints. Since here however—as shown in the section II-II in FIG. 8—the webs directly adjoining one another have been reduced accordingly in height compared to the more centrally located bars, the proportion of scattered radiation let through again increases to the “normal” amount otherwise prevailing in the grid module. FIGS. 7 and 8 show grid modules which exclusively have the inventive reduction of the web heights on two opposing sides. Such grid modules are especially advantageous if they individually cover the full width of the detector for a CT detector in the direction of the system axis and thus in each case only join other grid modules on their longitudinal side or on their side running in the direction of the system axis. If the grid modules are however embodied and disposed such that they adjoin further grid modules on more than two sides, an embodiment in accordance with FIGS. 9 to 12 can be especially advantageous. FIG. 9 shows two grid modules GM, in which the web height at all webs Sa, which form an outer side of the grid module and thus a potential joint surface is reduced. FIG. 10, by way of illustration, shows the longitudinal section III-III from FIG. 9, with the section II-II being identical to section II-II of FIG. 7 which was already shown in FIG. 8. A further improvement of the inventive embodiment of the grid modules can be seen in FIGS. 11 and 12. Here not only the webs Sa located directly on a joint line L are reduced in their height, but also at least one web Sb disposed further towards the center of the respective grid module. This additionally compensates for the scattered-radiation-reducing effect of the doubling of the webs at the joint surfaces, a further detector element lying in the second row or if necessary in rows further inwards. Naturally this measure shown running all around the grid modules in FIGS. 11 and 12 can also be embodied only on two opposing sides of the grid modules in a similar way to FIGS. 7 and 8 or if necessary also onto adjacent sides or only one single side—for example for grid modules on the edge of the detector. Overall at least one embodiment of the invention proposes a grid module of a scattered-radiation grid, a scattered-radiation grid comprising a number of grid modules arranged next to one another with a plurality of webs, especially for use in conjunction with a CT detector, a CT detector with a modular scattered-radiation grid and a CT system with such a detector, with inventively, at the joint surfaces of the grid modules, if necessary including the adjoining edge areas, the webs located there being embodied lower as regards their height than the maximum height of the other webs to be found in the grid module to compensate for an excessive reduction in scattered radiation. Although the invention has been illustrated and described in greater detail by the preferred exemplary embodiment, the invention is not restricted by the disclosed examples and other variants can be derived herefrom by the person skilled in the art, without departing from the scope of protection of the invention. The patent claims filed with the application are formulation proposals without prejudice for obtaining more extensive patent protection. The applicant reserves the right to claim even further combinations of features previously disclosed only in the description and/or drawings. The example embodiment or each example embodiment should not be understood as a restriction of the invention. Rather, numerous variations and modifications are possible in the context of the present disclosure, in particular those variants and combinations which can be inferred by the person skilled in the art with regard to achieving the object for example by combination or modification of individual features or elements or method steps that are described in connection with the general or specific part of the description and are contained in the claims and/or the drawings, and, by way of combinable features, lead to a new subject matter or to new method steps or sequences of method steps, including insofar as they concern production, testing and operating methods. References back that are used in dependent claims indicate the further embodiment of the subject matter of the main claim by way of the features of the respective dependent claim; they should not be understood as dispensing with obtaining independent protection of the subject matter for the combinations of features in the referred-back dependent claims. Furthermore, with regard to interpreting the claims, where a feature is concretized in more specific detail in a subordinate claim, it should be assumed that such a restriction is not present in the respective preceding claims. Since the subject matter of the dependent claims in relation to the prior art on the priority date may form separate and independent inventions, the applicant reserves the right to make them the subject matter of independent claims or divisional declarations. They may furthermore also contain independent inventions which have a configuration that is independent of the subject matters of the preceding dependent claims. Further, elements and/or features of different example embodiments may be combined with each other and/or substituted for each other within the scope of this disclosure and appended claims. Still further, any one of the above-described and other example features of the present invention may be embodied in the form of an apparatus, method, system, computer program, tangible computer readable medium and tangible computer program product. For example, of the aforementioned methods may be embodied in the form of a system or device, including, but not limited to, any of the structure for performing the methodology illustrated in the drawings. Even further, any of the aforementioned methods may be embodied in the form of a program. The program may be stored on a tangible computer readable medium and is adapted to perform any one of the aforementioned methods when run on a computer device (a device including a processor). Thus, the tangible storage medium or tangible computer readable medium, is adapted to store information and is adapted to interact with a data processing facility or computer device to execute the program of any of the above mentioned embodiments and/or to perform the method of any of the above mentioned embodiments. The tangible computer readable medium or tangible storage medium may be a built-in medium installed inside a computer device main body or a removable tangible medium arranged so that it can be separated from the computer device main body. Examples of the built-in tangible medium include, but are not limited to, rewriteable non-volatile memories, such as ROMs and flash memories, and hard disks. Examples of the removable tangible medium include, but are not limited to, optical storage media such as CD-ROMs and DVDs; magneto-optical storage media, such as MOs; magnetism storage media, including but not limited to floppy disks (trademark), cassette tapes, and removable hard disks; media with a built-in rewriteable non-volatile memory, including but not limited to memory cards; and media with a built-in ROM, including but not limited to ROM cassettes; etc. Furthermore, various information regarding stored images, for example, property information, may be stored in any other form, or it may be provided in other ways. Example embodiments being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. |
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claims | 1. An equipment for fabricating a semiconductor device, comprising:a particle beam source generating a particle beam to irradiate a semiconductor substrate with the particle beam through an opening of a stencil mask, the stencil mask having a thin film portion with the opening and a support portion supporting the thin film portion;a scanner scanning the particle beam;a mask measurement device measuring a position of a thin film portion or a supporting portion; andan arithmetic logic unit calculating the data measured by the mask measurement device and feeding back the results calculated with respect to at least one of the particle beam source and the scanner to control the region irradiated by the particle beam. 2. An equipment for fabricating a semiconductor device, comprising:a particle beam source generating a particle beam to irradiate a semiconductor substrate with the particle beam through an opening of a stencil mask, the stencil mask having a thin film portion with the opening and a support portion supporting the thin film portion,a scanner scanning the particle beam;an aperture shielding a part of the particle beam;a mask measurement device measuring a position of a thin film portion or a supporting portion;an arithmetic logic unit calculating data measured by the mask measurement device and feeding back the data to at least one of the particle beam source, the scanner and the aperture to control the region to be irradiated by the particle beam. |
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description | This application is a divisional of, and claims the benefit of priority to, U.S. Ser. No. 15/341,478, entitled “SYSTEM AND PROCESS FOR PRODUCTION AND COLLECTION OF RADIOISOTOPES”, filed on Nov. 2, 2016, the contents of which are incorporated herein by reference. This invention pertains generally to methods and devices for the insertion and removal of radioactive isotopes into and out of a nuclear core and, more particularly, to the insertion and removal of such isotopes that can remain in the nuclear core for at least the remainder of a full operating cycle after insertion. A number of operating reactors employ a moveable in-core detector system such as the one described in U.S. Pat. No. 3,932,211, to periodically measure the axial and radial power distribution within the core. The moveable detector system generally comprises four, five or six detector/drive assemblies, depending upon the size of the plant (two, three or four loops), which are interconnected in such a fashion that they can assess various combinations of in-core flux thimbles. To obtain the thimble interconnection capability, each detector has associated with it a five-path and ten-path rotary mechanical transfer device. A core map is made by selecting, by way of the transfer devices, particular thimbles through which the detectors are driven. To minimize mapping time, each detector is capable of being run at high speed (72 feet per minute) from its withdrawn position to a point just below the core. At this point, the detector speed is reduced to 12 feet per minute and the detector traversed to the top of the core, direction reversed, and the detector traversed to the bottom of the core. The detector speed is then increased to 72 feet per minute and the detector is moved to its withdrawn position. A new flux thimble is selected for mapping by rotating the transfer devices and the above procedure repeated. FIG. 1 shows the basic system for the insertion of the movable miniature detectors. Retractable thimbles 10, into which the miniature detectors 12 are driven, take the routes approximately as shown. The thimbles are inserted into the reactor core 14 through conduits extending from the bottom of the reactor vessel 16 through the concrete shield area 18 and then up to a thimble seal table 20. Since the movable detector thimbles are closed at the leading (reactor) end, they are dry inside. The thimbles, thus, serve as a pressure barrier between the reactor water pressure (2500 psig design) and the atmosphere. Mechanical seals between the retractable thimbles and the conduits are provided at the seal table 20. The conduits 22 are essentially extensions of the reactor vessel 16, with the thimbles allowing the insertion of the in-core instrumentation movable miniature detectors. During operation, the thimbles 10 are stationary and will be retracted only under depressurized conditions during refueling or maintenance operations. Withdrawal of a thimble to the bottom of the reactor vessel is also possible if work is required on the vessel internals. The drive system for insertion of the miniature detectors includes, basically, drive units 24, limit switch assemblies 26, five-path rotary transfer devices 28, 10-path rotary transfer devices 30, and isolation valves 32, as shown. Each drive unit pushes a hollow helical wrap drive cable into the core with a miniature detector attached to the leading end of the cable and a small diameter coaxial cable, which communicates the detector output, threaded through the hollow center back to the trailing end of the drive cable. The use of the Moveable In-core Detector System flux thimbles 10 for the production of irradiation desired neutron activation and transmutation products, such as isotopes used in medical procedures, requires a means to insert and withdraw the material to be irradiated from inside the flux thimbles located in the reactor core 14. Preferably, the means used minimizes the potential for radiation exposure to personnel during the production process and also minimizes the amount of radioactive waste generated during this process. In order to precisely monitor the neutron exposure received by the target material to ensure the amount of activation or transmutation product being produced is adequate, it is necessary for the device to allow an indication of neutron flux in the vicinity of the target material to be continuously measured. Ideally, the means used would be compatible with systems currently used to insert and withdraw sensors within the core of commercial nuclear reactors. Co-pending U.S. patent application Ser. No. 15/210,231, entitled Irradiation Target Handling Device, filed Jul. 14, 2016, describes an Isotope Production Cable Assembly that satisfies all the important considerations described above for the production of medical isotopes that need core exposure for less than a full fuel cycle. There are other commercially valuable radioisotopes that are produced via neutron transmutation that require multiple neuron induced transmutation reactions to occur in order to produce the desired radioisotope product, or are derived from materials having a very low neutron interaction cross section, such as Co-60, W-188, Ni-63, Bi-213 and Ac-225. These isotopes require a core residence time of a fuel cycle or more. Commercial power reactors have an abundance of neutrons that do not significantly contribute to the heat output from the reactor used to generate electrical power. This invention describes a process and associated hardware that may be used to utilize the neutron environment in a commercial nuclear reactor to produce commercially valuable quantities of radioisotopes that require long-term neutron exposure with minimal impact on reactor operations and operating costs. This invention provides a nuclear fuel assembly target flux thimble insert for irradiating a target material over an extended portion of a fuel cycle and harvesting the irradiated target material at the end of the fuel cycle. The flux thimble insert includes an elongated tubular housing having an axis along its elongated dimension. The elongated tubular housing is closed at a forward end and capped at a rearward end to form a target specimen chamber there between within an interior of the elongated tubular housing. The elongated tubular housing is sized to slide within an instrument thimble of a nuclear fuel assembly resident within a reactor core, with the rearward or trailing end structured to be driven by a drive cable of an existing moveable in-core detector system. An elongated target specimen is captured within an interior of the elongated tubular housing between a forward and a rear axial position plug, with the axial position plugs structured to seat against an interior wall of the elongated tubular housing to hold the target specimen at a preselected axial position within the interior of the elongated tubular housing. In one embodiment, the target specimen is formed from one or more of Co-60, W-188, Ni-63, Bi-213 and Ac-225. Preferably, the elongated tubular housing is constructed from a material having a low neutron capture cross-section such as, for example, zirconium or a zirconium alloy. In another embodiment, the axial position plugs maintain their axial position due to friction between interfacing surfaces on the axial position plugs and the interior wall of the elongated tubular housing. Alternately, the axial position plugs may maintain their axial position by fitting into slight recesses in the interior wall of the elongated tubular housing or a combination of both designs may be employed. Preferably, in the embodiment that employs recesses for the axial position plugs, the upper and lower surfaces of the axial position plugs that extend substantially orthogonal to the axis have an outer substantially circular wall extending there between with the dimension of the outer, substantially circular wall sized to fit into one of the recesses. Preferably, in the latter embodiment the interface of the upper and lower surfaces with the outer, substantially circular wall are slanted at an acute angle to facilitate lodging and dislodging of the axial position plugs from the recesses. The invention also contemplates a method of irradiating an isotope that requires an extended exposure within a nuclear reactor lasting at least one fuel cycle, to achieve an intended target product. The method comprises the step of enclosing the isotope within an elongated tubular housing having an axis along its elongated dimension. The elongated tubular housing is closed at a forward end and capped at a rearward end to form a target specimen chamber therebetween within an interior of the elongated tubular housing. The elongated tubular housing is sized to slide within an instrument thimble of a nuclear fuel assembly, with the rearward end structured to be driven by a drive cable of an existing moveable in-core detector system. The isotope is then positioned at a preselected axial position within the elongated tubular housing and the rearward end of the housing is attached to the drive cable. The isotope within the elongated tubular housing is then driven at least partially through an instrument thimble of a selected nuclear fuel assembly within a core of a nuclear reactor and left within the core for the remainder of the fuel cycle. The elongated tubular housing is removed from the core at the end of the fuel cycle and the selected fuel assembly removed from the core. The elongated tubular housing is then reinserted into the core location and a portion of the elongated tubular housing containing the isotope is then removed from the drive cable. In one embodiment, the removed portion of the elongated tubular housing is transferred under water to a spent fuel pool where it may be packaged for shipment. One preferred embodiment of the radioisotope production process of this invention utilizes the flux thimbles that provide the access conduit for the existing movable in-core detector fission chambers to the instrument thimble in the fuel assembly to periodically measure the reactor power distribution, to insert the target material to be transmuted into a desired radioisotope, into the fuel assembly instrument thimble. The flux thimble containing the target material, hereafter referred to as the target flux thimble 34, is shown schematically in FIG. 2 and takes the place of the miniature detector 12 shown in FIG. 1 as being inserted into the fuel assembly instrument thimble 50. The target flux thimble 34 is attached to the drive cable 48 in place of the miniature detector 12 and comprises an outer sheath 36 having an enclosed lead end 38 that is preferably rounded or beveled and an enclosed trailing end 40 that is enclosed by a cap 42 once the specimen or isotope target capsule 44 has been loaded within the chamber 45 within the outer sheath 36. The target material capsule 44 may have its own sheath (not shown) or if in solid self-standing form may be capped at either axial end by axial position end plugs 46 that position the target material capsule 44 in a desired axial position within the target flux thimble 34. The axial position end plugs may be held in position by friction or fit in slight recesses 52 in the inside surface of the target flux thimble sheath 36 preferably with the interfacing surface of the axial position end plugs beveled to assist movement of the axial position end plugs into the recesses when they are loaded into the target flux thimble sheath 36. The target flux thimble 34 remains in place within the fuel assembly instrument thimble 50 throughout the remainder of the reactor operating cycle after it is installed within the fuel assembly instrument thimble. When the reactor is refueled all the flux thimbles are withdrawn below the lower core plate inside the reactor vessel to allow the fuel assembly to be shuffled and/or removed from the vessel as part of the refueling process. If the amount of the desired radioisotope is expected to be sufficient inside a target flux thimble, the target flux thimble can be re-inserted into the empty reactor vessel location previously occupied by the removed fuel assembly to allow the portion of the target flux thimble containing the irradiated target material that was inside the fuel assembly instrument thimble to be cut off from the target flux thimble using existing tooling dedicated to flux thimble removal operations. FIG. 3 provides an illustration of the positioning of the target flux thimble during the irradiation, refueling, and harvesting phases of production. Like reference characters are used among the several figures to represent corresponding components. Reference character 22 points to the guide conduits through which the target flux thimble 34 travels from the seal table 20. The guide conduits 22 are each aligned with a corresponding instrument column 56, which is aligned with a corresponding instrument thimble in one of the fuel assemblies in the core. Reference character 54 points to the fully inserted target flux thimble position in the corresponding fuel assembly in the core at which the target material capsule will be irradiated and reference character 58 refers to the fully withdrawn position that enables the corresponding fuel assembly to be withdrawn from the core, prior to harvesting the target material. Reference characters 68 and 70, respectively, show the difference of the fully withdrawn position and the fully inserted position at the seal table 20. After the fuel assembly is withdrawn from the core the target flux thimble 34 can be reinserted into the core area and severed at reference character 60 for removal from the reactor vessel. The irradiated target material can then be inserted into a container 62 that will allow the target material containing target flux thimble portion to be transferred via the fuel transfer system 66 to the spent fuel pool 64 where it can be packaged in a shielded shipping container 72 to ship to a processing facility. The remaining portion of the affected target flux thimble is removed using standard maintenance procedures and is replaced with a new target flux thimble. The process can be repeated as many times as desired, and simultaneously in as many different core locations as prudent to ensure that at least 75% of the fuel assembly locations hosting flux thimbles are available throughout the operating cycle. The typical prior art method for producing commercially valuable radioisotopes that require long term irradiation inside commercial nuclear reactors involves inserting one or more fuel pin structures that contain the target material into one or more fuel assemblies. The process offered by this invention avoids the need to perform the very rigorous, time consuming and expensive analysis needed to support modifications to a licensed fuel assembly design to incorporate the modified fuel pin structures. The fuel assembly instrument thimbles that are accessed via the flux thimbles by the moveable in-core detector fission chambers do not require any modifications. Since there are no modifications to the fuel assembly design required by the approach documented herein, there is little cost associated with implementation of this process. The irradiation of target materials to produce a desired radioisotope is the first step in the production of any commercially valuable radioisotope. Consequently, the potential business is the entire breadth of the longer lived radioisotope production market. Some notable highly desired (and priced) radioisotopes suitable for the production process addressed by this invention include Co-60, W-188, Ni-63, Bi-213, and Ac-225. The process described herein lends itself to the use of radioactive target material since the ability to shield the target material before it is irradiated is supported by the existing features of the moveable in-core detector architecture. While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular embodiments disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any and all equivalents thereof |
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abstract | A method and a device are provided for monitoring a power rise during startup of a nuclear reactor (diversitary excursion monitoring). In order to be able to shut down the reactor during startup in the event of prompt critical states, a power band situated in a lower measuring range is prescribed for a signal of power range channels which detects the reactor power in the power range. Startup is continued only when the signal does not exceed an upper limit within a minimum time, after the last occasion of exceeding a lower limit of the power band. |
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summary | ||
042788900 | abstract | A beam of ions is directed under control onto an insulating surface by supplying simultaneously a stream of electrons directed at the same surface in a quantity sufficient to neutralize the overall electric charge of the ion beam and result in a net zero current flow to the insulating surface. The ion beam is adapted particularly both to the implantation of ions in a uniform areal disposition over the insulating surface and to the sputtering of atoms or molecules of the insulator onto a substrate. |
054935997 | description | DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIG. 1, a CT scanner includes a toroidal ring x-ray tube I which is mounted to a gantry or mechanical mounting assembly II, and an electronics section III. The electronic section provides operating power and control signals to the gantry, receives data from the gantry, reconstructs the received data into an electronic image representation, and converts the electronic representation to human readable form. With reference to FIG. 2, the ring tube I includes a toroidal housing A which defines a large, generally donut-shaped interior volume. A ring anode B is mounted within the toroidal housing interior volume and extends circumferentially therearound. A cathode assembly C is disposed within the toroidal housing interior space for generating at least one beam 10 of electrons. A motor D selectively rotates the cathode or otherwise rotates the electron beam around the anode B. More specifically, the anode B is a tungsten ring having a tungsten face 12 upon which the electron beam 10 impinges. The interaction of the electron beam 10 and the anode face 12 generates a hemisphere x-ray flux 14 (FIG. 3) for collimation into a usable x-ray beam 16, as described below. The anode assembly defines an annular anode adjacent cooling fluid path or channel 18 in intimate thermal communication with the anode face, specifically along an opposite surface of the anode. Optionally, the anode can have internal passages, fins, and the like to promote thermal communication with the cooling fluid. A rotor, or rotating frame, 20, such as a rotating annular ring or frame is mounted for rotation around an interior of the toroidal housing A. The rotating frame 20 supports a corresponding plurality of cathode assemblies C. Each of the cathode assemblies includes a cathode cup 22 which contains a filament 24 or other electron source and a cathode control circuit 26. The filament 24 and the anode face 12 are maintained at a high relative voltage relative to each other, e.g. 150 kV. The housing A and the rotating frame 20 are maintained at a common potential, preferably ground potential. In the preferred embodiment, the anode is also maintained at ground potential and the cathode cup is insulated from the rotor 20 and maintained at about -150 kV. Alternately, the anode may be maintained at approximately +75 kV and the cathode at about -75 kV relative to ground. The rotating frame 20 is rotatably supported within the housing A for rotation about a central axis 28 on a bearing 30, a magnetic levitation bearing in the preferred embodiment. The magnetic levitation bearing 30 includes rings of silicon steel 32, which are stable within the vacuum, mounted along an inner radius of the rotating frame 20. Passive and active elements including permanent magnets 34 and electromagnets 36 are disposed closely adjacent the rings 32 of silicon steel. The housing A includes a magnetic window 38 which separates the vacuum region from the electromagnets 36. The magnetic window, such as an aluminum film, permits magnetic flux to pass but prevents epoxy or other polymers commonly used in coils from outgassing into the vacuum region. To maintain the alignment of the rotating frame 20, a pair of oppositely disposed magnetic levitation bearings 40 are mounted on opposite sides of the rotor. Each has rings of silicon steel 42 and permanent magnets 44 to provide opposing forces on the rotor. The magnetic levitation bearing on one side also has electromagnetic coils 46 to adjust the relative opposing forces. The electromagnet is again shielded from contaminating the vacuum by an aluminum film or other magnetic window. Position sensors, not shown but conventional in the art, are provided for controlling the electromagnetic coils to maintain the position of the rotor 20 precisely during rotation. The motor D is preferably a large diameter brushless ring motor 50. The motor includes rotor 52, preferably of permanent magnets, mounted to the rotating frame 20 within the vacuum region. A stator 54, including electromagnetic windings, is positioned directly opposite the rotor 52 but across the magnetic window 38 outside of the vacuum region. Mechanical roller bearings 56, normally out of contact with the rotor, are provided to support the rotor 20 in the event the magnetic levitation system should fail. The mechanical roller bearings prevent the rotor 20 from interacting directly with the stationary housing A and other associated structures. An angular position monitor 58 monitors the angular position of the rotation of the rotating frame 20, hence the angular position of the cathode assemblies and the apices of the x-ray beams precisely. A detector ring 60 is disposed around a patient aperture 62 that is surrounded by the housing A to detect x-rays that have exited the housing through an x-ray transmissive window 64. The detector ring 60 includes a ring of x-ray detectors 66, such as optically coupled scintillation crystals and photodiodes. A detector electronics section 68 includes preamplifiers, filters, analog-to-digital converters, and the like. Referring now more particularly to FIG. 3, along with FIG. 2, an off-focal radiation shield, or pre-collimator, 70 is mounted to the rotating frame 20 in alignment with each cathode C disposed thereon. In the preferred embodiment, eight cathodes and off-focal radiation, or pre-collimator, shields, or pre-collimators, 70 are used. In the pre-collimator shield 70, an aperture or slot 72 is cut slightly wider than the maximum selectable thickness of the x-ray beam 16. The length of the slot defines the width or arc of the x-ray beam 16. The pre-collimator shield 70 is preferably made of a high z material, such as tantalum or tungsten, and is placed as near to the focal spot as possible to shield the environment from x-rays. Preferably, the pre-collimator shield 70 is held at a negative potential such that it repells backscattered electrons. This prevents back scattered electrons from interacting with the pre-collimator 70 to produce x-rays. Further, however, it is recognized that the proximity of the pre-collimator 70 to the anode is limited due to their potential difference. A pre-collimator 74 which is constructed of a high z radiation blocking material is directly mounted to the anode B. The pre-collimator (74) has a window, such as an annular slot 76 that sets a maximum limit on the thickness of the x-ray beam 16. A support structure 78 such as a ring of low z material, supports the portion of the pre-collimator 74 extending beyond the slot 76. The pre-collimator 74, which is at ground potential and bonded to the anode, limits out-of-plane off-focal radiation seen by the x-ray detection system 60. In the preferred embodiment, the annular sections that define the slot 76 are bonded with a beryllium sheet 78. The gradient of the electric field generated near the anode focal track allows backscattered electrons to be attracted to the stationary pre-collimator 74. The backscattered electrons that return to the anode B is accordingly reduced. The number of backscattered electrons that strike the beryllium surface produce only 5.5% of bremsstrahlung x-rays usually produced by a tungsten surface. Beryllium of the thickness required is highly transmissive to x-rays of diagnostic energies and does not adversely affect the x-ray spectrum. The heat produced from the bombardment of backscattered electrons is conducted directly to the anode and is removed from the x-ray tube by the anode cooling water. A rear or outer peripheral anode shield 80 blocks portions of the x-ray flux 14 from escaping radially outward. Rear anode shield 80 is preferably formed of a high z material, i.e., a high atomic number material, and is disposed on an opposite side of the anode B relative to the pre-collimator 70. The rear anode shield 80 is directly mounted on the anode B in a known manner. The high z material used in the pre-collimator 74 and shield 80 near the annular anode B is an effective x-ray shield. This strategically located x-ray shield reduces the amount of shielding material needed at more distant locations. The overall weight of the x-ray tube is thus reduced. In alternative embodiments, different combinations of the pre-collimators 70 and 74 and rear anode shield 80 are used. For example, in one embodiment, only the pre-collimator 70 is provided. In another embodiment, only pre-collimator 74 is utilized. In still yet other embodiments, the rear anode shield is selectively used with the aforenoted, and other, configurations of the pre-collimators. Referring now to FIG. 4, a ring collimator 90 includes a fixed ring 92 and a movable ring 94. The movable ring 94 moves toward and away from the fixed ring 92 to adjust a distance therebetween. The distance between the fixed ring 92 and the movable ring 94 determines the x-ray beam thickness hence the slice thickness. The slice thickness is adjusted by translating the movable ring 94 toward the fixed ring 92 for thinner slices and by translating the movable ring 94 away from the fixed ring 92 for thicker slices. Advantageously, the central position of the x-ray beam is changed one-half the distance of the total adjustment of the movable ring 94. Such repositioning is accomplished using mechanical, electrostatic, and/or electromagnetic adjustment mechanisms and structures. The fixed ring 92 is positioned on mounting pads 96 with its center coincident with the central axis 28. The geometric plane of the fixed ring is adjusted to be parallel with the geometric plane of tungsten ring anode surface 12, both of which are perpendicular to the central axis. A plane alignment for any one of the cathodes C is typically satisfactory for all the cathodes. Variations in the alignment of the cathodes C on the rotating frame 20 will affect the beam landing track on the ring anode B. The x-ray plane and the fixed ring plane of fixed ring 92 has a constant spacing to preserve the angle of incidence of x-rays with the fixed ring 92. The angle is preferably constant for any cathode C that is selected. One preferred manner of suitably adjusting the movable ring 94 is to utilize a fine pitch screw thread drive. As shown in FIG. 4, a fine pitch screw thread 98 is machined in the outer periphery of the movable ring 94. A fine pitched screw thread, not shown, is also machined on a mating assembly on a mounting pad 100 attached to the scanner. The linear motion for slice thickness selection is preferably accomplished by rotating the movable ring 94 relative to the mounting pad 100 with a rotary motor drive mechanism 102. Conventional worm or helical gear configurations are preferred for this operation. Alternatively, an annular ring constructed of low density and low atomic materials can be used to join the threaded fixed ring 92 and movable ring 94. It is recognized that thread configurations on the fixed ring 92 and movable ring 94 can be reversed such that the forward ring is movable and the rearward ring is not movable. As yet another option, both rings can move in coordination with each other. In a further alternative, outer screw threads can be machined directly into the ring tube housing. In an alternative embodiment, the adjustment means is a linear motion drive mechanism. The linear motion drive mechanism adjusts the gap between the two rings by controlling one or more identical mechanisms that translate the movable ring to suitable positions without the use of threads or the rings. Generally, three or more linear drive mechanisms effectively drive the adjustable ring 94. It is preferred that the linear drive mechanism be capable of positioning the ring to 0.0005 of an inch accuracy. In the alternate embodiment of FIGS. 5 and 6, movable ring 94 has a smaller diameter than the fixed ring 92. The two rings, 92 and 94 overlap to function as a shutter to absorb all x-radiation. The movable ring 94 is translated to a position beyond a center line 104, as shown. The shutter function is primarily useful for service applications in which the x-ray tube is energized but radiation in the examination room is undesirable. The shutter effect described in connection with FIGS. 5 and 6 provides a significant advantage over known systems in which a separate shutter and collimator are used. The instant development reduces the necessity of incorporating two separate mechanisms into the x-ray thus increasing efficiency and reducing the number of mechanisms needed. The present development has been described placing particular emphasis on an x-ray tube using a stationary ring anode and a rotating cathode. However, as shown in FIG. 7, features of the present application are also applicable to an x-ray tube utilizing a rotating anode 110 having an anode face 112 and a stationary cathode 114. An election beam is directed by cathode 114 to the anode face 112 to generate x-rays which are transmitted through a pre-collimator 116. The pre-collimator 116, which is formed of a material having a high atomic number, is disposed on support structure, or ring, 118 so that a slot 120 can be formed in the pre-collimator 116 without the need for additional structure to support portions of the pre-collimator extending beyond the slot. The support structure 118 is preferably made of a material having a low atomic number. The invention has been described with reference to preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof. |
abstract | A nuclear reactor cooling system with passive cooling capabilities operable during a reactor shutdown event without available electric power. In one embodiment, the system includes a reactor vessel with nuclear fuel core and a steam generator fluidly coupled thereto. Primary coolant circulates in a flow loop between the reactor vessel and steam generator to heat secondary coolant in the steam generator producing steam. The steam flows to a heat exchanger containing an inventory of cooling water in which a submerged tube bundle is immersed. The steam is condensed in the heat exchanger and returned to the steam generator forming a closed flow loop in which the secondary coolant flow is driven by natural gravity via changes in density from the heating and cooling cycles. In other embodiments, the cooling system is configured to extract and cool the primary coolant directly using the submerged tube bundle heat exchanger. |
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abstract | The equipment operability evaluation apparatus calculates the operating posture of a human body model based on the physique information about a human body model in a physique management table, the operation information in an operation management table, and the target information in a target management table, arranges an equipment model and the human body model taking the calculated operating posture in a three-dimensional virtual space, displays a view image of a three-dimensional virtual space from the point of view of the human body model, and determines the visibility about the target operation area of the equipment model displayed on the view image and the readability of a character string. |
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046801596 | summary | FIELD OF THE INVENTION The invention relates to a storage container for receiving fuel rods of irradiated nuclear reactor fuel elements. The storage container includes a storage chamber having a circular cross-section for accommodating an insert cage for holding cans filled with fuel rods. BACKGROUND OF THE INVENTION For the transportation and storage of irradiated nuclear reactor fuel elements, it is customary to utilize shielded transport and storage containers made of spheroidal cast iron or steel. The inner chamber of the containers can have a round or square cross-section. Containers with a circular inner chamber have the advantage of being easier to manufacture and of optimally utilizing the storage space. The irradiated fuel elements are received in these storage containers in special insert cages. In addition to the accommodation of complete fuel elements, it has already been proposed to disassemble the fuel elements and to load the individual fuel rods of these fuel elements closely packed into a storage container. Considerable space savings can be achieved thereby. European Pat. No. 0005623 discloses that the storage container is thus capable of holding a larger amount of fuel elements. According to a state-of-the-art disclosure made in German published patent application No. DE-OS 3,222,822, the fuel rods removed from the fuel elements are closely packed into cans the geometry of which corresponds approximately to one fuel element. The filled cans are then placed into the receiving shaft-like compartments of the insert cage, these compartments being actually configured to hold the fuel elements. An important technical problem of the storage of individual fuel rods packed as closely as possible in a storage container is the temperaure control of this storage unit. As a result of the decay heat of the radioactive fuel, the temperature within the storage unit may increase inadmissibly. Dissipating the heat from the interior of the fuel rod package involves problems. Consequently, this heat dissipation problem may be the reason for limited packing densities or extended previous decay times of the fuel elements until they can be loaded into the storage container. SUMMARY OF THE INVENTION It is therefore an object of the invention to configure a container of the type initially described such that a good heat dissipation from the storage unit is accomplished and that the fuel rods are not impermissibly impaired by heat. This object is achieved by the storage container of the invention in that: the individual cans are arranged in circular form in the insert cage; the cross-section of the cans is a circular segment; hold-down springs bear on the upper end surfaces of the cans; and, the radial extension of the can segments towards the center is limited so that an empty square shaft is formed in the middle of the insert cage. Providing the individual fuel-rod cans with a circular-segmental cross-section adapts them well to the round cross-section of the storage space. The curved rear surfaces of the fuel-rod cans rest snugly against the circular inner wall of the container, thereby providing for a good heat transfer between the cans and the storage container. The hold-down springs urge respective ones of the fuel-rod cans in an axially parallel direction against the bottom of the storage container so that the good heat transfer is ensured there also. The empty square shaft formed in the middle of the storage space may be used to accommodate the scrap, that is, spacers and the like which result from separating out individual fuel rods. This structural material of the disassembled fuel elements has a substantially lower heat output than the fuel rods. In addition, it is not affected by heat and is capable of tolerating heat increases unprotected. By contrast, the irradiated fuel rods are not permitted to exceed the temperature limits prescribed by the authorizing governmental agencies because of the risk of leakage. Fissile gases or other radioactive material would then escape. According to another feature of the invention, double-walled partition units define a hollow space between two adjacent fuel-rod cans. Sectioning the circular storage space in this manner permits fuel-rod cans of identical configuration to be used. Advantageously, one fuel-rod can will accommodate the fuel rods of one fuel element. In addition, the hollow spaces in the partition segments afford the possibility of loading neutron-absorbing or heat-conductive materials. A feature of this embodiment of the invention is that the fuel-rod cans can be made to all have the same configuration. In another advantageous embodiment of the invention, inclined guides coact with inclined engagement surfaces in the insert cage, and lower guide surfaces eliminate a clearance which may be present between the curved rear surfaces of the fuel-rod cans and the circular inner wall of the storage container. The invention provides a storage container for accommodating individual fuel rods, which permits the storage of fuel rods having a higher after-heat output. Therefore, after removal of the fuel elements from the spent fuel storage pool and their disassembly into individual fuel rods, the fuel rods may be directly loaded into the container provided for terminal storage. Further interim storage for heat dissipation is not necessary. |
abstract | Ion beam lithography technique wherein a higher amount of radiation energy is deposited to predetermined regions in the bulk if a suitable substrate. By selecting the radiation nature, its energy and the irradiation parameters a structure can be created in the bulk of the material leaving the surface essentially untouched. |
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063174839 | summary | TECHNICAL FIELD The present invention relates to doubly curved optical elements, and in particular, to a doubly curved optical device having multiple reflection planes separated by a spacing d which varies in at least one direction. BACKGROUND OF THE INVENTION Crystalline materials, which have periodic structure, can be used to reflect x-rays based on diffraction. The reflection of x-rays from crystal planes can only occur when the Bragg condition is met: EQU 2d sin .theta.=n.lambda. Where .lambda. is the x-ray wavelength, d is the spacing of reflection planes, .theta. is the incident angle with respect to the reflection planes, and n is the reflection order. The d spacings for natural crystals and most synthetic crystals are constant. In order to reflect x-rays of the same wavelength efficiently, a crystal optical element must have a near constant incident angle with respect to the reflection planes of the crystal on every point of the surface. Crystal optics based on Bragg reflection have been widely used for x-ray monochromators and high-resolution spectroscopy. However, the applications of crystal optics for focusing and collimating x-rays from a laboratory source have been limited because of the strict requirement of the Bragg condition and the narrow rocking curve widths for most useful crystalline materials. For many applications of microanalysis, an intense monochromatic x-ray beam based on a laboratory type source is needed. Three-dimensional focusing of x-rays from a laboratory source involves doubly bent crystal optics. The practical use of a toroidal crystal to focus 8 ke V x-rays has been demonstrated recently with the use of a mica crystal based on the Johann type point to point focusing geometry. For example, reference an article by Z. W. Chen and D. B. Wittry entitled "Microanalysis by Monochromatic Microprobe X-ray Fluorescence-Physical Basis, Properties and Future Prospects", J. Appl. Phys., 84(2), page 1064 (1998). However, the Bragg condition cannot be satisfied on every point of the crystal using this approach due to the geometrical aberration of the Johann geometry in the Roland circle plane, which will limit the collection solid angle of the optic. The spot size of the focused beam is also limited by the geometrical aberration of the toroidal surface. On the other hand, a parallel monochromatic x-ray beam is useful for many x-ray diffraction applications. Conventional crystal optics with constant d spacing cannot provide efficient collimation of hard x-rays from a divergent source since the incident angle must vary from point to point for any type of collimating mirror. For high-resolution x-ray diffraction applications, the monochromaticity provided by conventional multilayer optics is relatively poor and the divergence is not small enough. SUMMARY OF THE INVENTION Briefly summarized, the present invention comprises in one aspect an optically curved device which includes a plurality of curved atomic planes, at least some of which are separated by a spacing d which varies in at least one direction. The device further includes an optical surface which is doubly curved and disposed over the plurality of curved atomic planes. The spacing d varies in the at least one direction and is determined from a Bragg equation, where a Bragg angle is an incident angle of an x-ray from a source impinging on the optical surface on at least some points of the optical surface. To restate, it is an object of this invention to provide significantly improved curved crystal optical elements for focusing, collimating and imaging of x-rays. These curved crystal optics are characterized in that the lattice parameters change laterally in at least one direction. The variation of the crystal lattice parameter can be produced by growing a crystal made of two or more elements and changing the relative percentage of the two elements as the crystal is grown. By varying the d spacing laterally across the surface of a crystal optic, the Bragg angle .theta. on every point of the crystal can be matched to the incident angle exactly, which improves significantly the efficiency of curved crystal elements and eliminates any geometric aberration. The optical shapes of two-dimensionally curved graded crystal elements can be circular, ellipsoidal, parabolic, spherical, and other aspherical shapes. An example of a doubly curved element is given in FIGS. 3A & 3B. FIG. 3A shows that the element can be elliptically curved in one-dimension, while FIG. 3B shows that the element can be circularly curved in the other dimension. This provides point-to-point focusing. The ellipsoidal geometry provides point to point focusing of monochromatic x-rays. Graded crystal elements with an ellipsoidal shape can capture a large solid angle from a small x-ray source and form a micro monochromatic x-ray beam, useful for micro beam analysis, e.g., monochromatic micro XRF (X-ray Fluorescence), small spot XPS (X-ray Photoelectron Spectroscopy). The paraboloid geometry provides a collimating x-ray beam from a point source. Crystal elements with graded d spacing planes curved to a paraboloid shape can capture significant solid angle and produce a collimating beam from a pont-type laboratory source. Due to the narrow energy bandwidth of the crystal optic, the collimating beam can be highly monochromatic with small divergence, which is required for high-resolution x-ray diffraction. Finally, graded crystal optics with a spherical geometry can be applied to image hard x-rays. The combination of spherical optics, such as Schwarzschild optics, can provide strong demagnification and form a sub-micron x-ray beam based on a laboratory source. |
description | 1. Field of the Invention The present invention relates to a method of transferring a pattern of a reticle onto a substrate, a computer readable storage medium, and a method of manufacturing a device. 2. Description of the Related Art In a lithography process for manufacturing a semiconductor, predetermined patterning is performed using a reticle (mask). Note, however, that when a new exposure apparatus is introduced into this process, it usually has a performance different from that of the existing exposure apparatus. For this reason, to obtain a transfer pattern identical to that obtained by the conventional exposure apparatus, the new exposure apparatus is to be adjusted. Also, to improve the device characteristics, the current transfer pattern may be slightly modified. Ideally, in this case, it would be tempted to fabricate another reticle suited to that improvement. However, from the standpoint of practicality, it would better to form a target pattern by adjusting the exposure apparatus, instead of fabricating another expensive reticle for such a slight modification. Exposure parameters which influence the pattern shape on a substrate (wafer) include, for example, the illumination intensity distribution, lens numerical aperture (NA), lens aberration, and light source wavelength bandwidth. Of these exposure parameters, the most influential one is the illumination condition such as the illumination mode. Although the NA is relatively influential, it has only one numeric parameter. This makes it difficult to partially adjust the NA and undesirably changes the resolving performance. Although the aberration is relatively influential as well, a leading-edge exposure apparatus has less aberration and its contribution ratio is therefore low. Under the circumstances, it is a common practice to achieve the foregoing object by adjusting the illumination condition. There are the following two working methods of deforming a transfer pattern to have a certain target value. In the following description, the illumination mode is assumed to be generally represented by numeric parameters. For example, annular illumination is represented by the outer σ and the inner σ. [Method 1] First, the rate of dimensional change (to be referred to as the “sensitivity” hereinafter) in response to a change in parameter in each illumination mode is obtained for each evaluation point. Then, the amount of change from the current dimension to the target dimension at each evaluation point is divided by the sensitivity to obtain a parameter value to be changed in each illumination mode. In this case, the amount of dimensional change typically has a level on the order of several nanometers, and no large error is generated in this range even if the sensitivity is assumed to be linear. Although the sensitivity is easily obtained by optical image computation, a difference naturally occurs between an experimental value and the computed value. In view of this, a method of actually slightly changing the illumination condition and measuring the dimension experimentally is commonly employed. Details of this method are described in Proc. of SPIE, Vol. 6924, 6924Q 1-12. [Method 2] The contour of the pattern on the wafer is computed under a certain illumination condition. The RMS (Root Mean Square) or maximum value of a set of the differences between the values representing the computed contour and the target values at a plurality of pattern adjustment positions is obtained. The obtained value is set as an index value. Next, the illumination condition is slightly changed, and an index value is obtained for the changed illumination condition. By repeating this sequence in the space to set the illumination condition, an illumination condition under which the index value is minimum is obtained. To obtain that illumination condition, a mathematical method such as a genetic algorithm method or a Monte Carlo method is used. Details of this method are described in Shigenobu Kobayashi, “Toward A Breakthrough of Real-coded Genetic Algorithms”, Proceedings of Symposium on Evolutionary Computation 2007 (Date: Dec. 27-28, 2007; Venue: Hokkaido Toya Lake), Society for Evolutionary Computation. The contour of the pattern on the wafer is computed by optical computation or resist image computation. Note that in this technical field, resist image computation is basically used because of the necessity of matching with the experimental results. Resist image computation includes a scheme of physically precisely computing a resist image, and a scheme of computing a resist image based on correlation between an experimental value and the computed value of an optical image. The former scheme has the demerit of consuming a relatively long computation time, so the present invention employs the latter scheme which consumes a relatively short computation time and has features to be described later. The computation method which uses a resist image will be explained herein. First, several types of model extraction patterns having simple line-and-space structures and line ends are selected as patterns to be transferred and measured experimentally. Although only several types of model extraction patterns are selected, they each have several tens to several hundreds of different line widths, space widths, and line end widths. The image log slopes (ILSs) and the curvatures at feature points on these model extraction patterns are computed from their optical images. The ILSs are defined by:ILS=d ln(I)/dx where I is the light intensity, and x is the position. The curvatures are computed by dividing the contour into small curves, fitting them by parts of circles, and determining the radii of the circles as the curvatures. A difference δ between the computed value of an optical image and an experimental value at each of the feature points is expressed by:δ=a× curvature+b×ILS+c where a, b, and c are constants. These values are fitted for all evaluation points to determine the constants a, b, and c. Construction of this relation is commonly called model construction. When the model is determined, the above-mentioned difference is determined by computing the ILS and the curvature from the optical image at an arbitrary position on the pattern, and the resist pattern dimension is then calculated. In method 1, if a plurality of evaluation points are present, different illumination condition optimum solutions are sometimes obtained at these evaluation points. In this case, an averaging process or a weighting process, for example, is performed. However, such a process rarely has a physical ground, so the overall matching accuracy at all evaluation points is inevitably decreased. It is also necessary to define the contribution ratios of a plurality of existing illumination conditions. Such a process rarely has a physical ground as well, so the overall matching accuracy at all evaluation points is again inevitably lowered. In method 2, an illumination condition under which the transfer pattern is closest to a target value is mathematically obtained. The calculated solution therefore should be theoretically correct. Despite this expectation, the practical application of the calculation result obtained in method 2 is not free from errors due to, for example, computational errors of a resist image used in a mathematical process, and deviations between the numerical definition of the illumination condition and the setting of an actual exposure apparatus. The present invention has been made in consideration of the above-described situation, and accurately, easily determines the illumination condition of a reticle in a lithography process including a step of transferring the pattern of the reticle onto a substrate. According to an aspect of the present invention, there is provided a method of transferring a pattern of a reticle onto a substrate, the method comprising: setting a target pattern to be formed on the substrate using the reticle; obtaining a first pattern transferred onto a substrate by exposure using the reticle and a first illumination condition; calculating, a virtual second illumination condition under which the target pattern is transferred onto a substrate using the reticle, and a virtual third illumination condition under which the first pattern is transferred onto a substrate using the reticle, using mathematical models each of which defines a relationship between an illumination condition and a virtual pattern transferred onto a substrate using the illumination condition; determining a fourth illumination condition, obtained by adding a difference between the calculated second illumination condition and third illumination condition to the first illumination condition, as an illumination condition under which the target pattern is transferred onto a substrate using the reticle; and transferring the pattern of the reticle onto the substrate by illuminating the reticle using the determined illumination condition. Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. A method of determining the illumination condition of a reticle in a lithography process including a step of transferring the pattern of the reticle onto a substrate by an exposure apparatus will be described below. Note that the illumination condition includes the light intensity distribution (effective light source) on the pupil plane of an illumination (projection) optical system. In a first embodiment, conceptual description will be given first with reference to FIG. 1A. A dotted line in FIG. 1A describes a first pattern (transfer pattern) transferred onto a substrate by actual exposure under a first illumination condition A using a reticle. A solid line in FIG. 1A describes a target pattern to be formed on a substrate using the same reticle as used in the former transfer. In one embodiment, the calculation target is an illumination condition B under which the target pattern is transferred onto a substrate using the same reticle. Note that a plurality of types (e.g., nine types in FIG. 1A) of reticle patterns having a plurality of lines with different pitches are used, as shown in FIG. 1B. The ordinate in FIG. 1A indicates the dimension of a line positioned at the center of each transfer pattern. A virtual third illumination condition for reproducing the transfer pattern [Dimension Mi; i=1, . . . , n] (a dotted line in FIG. 1A) transferred under the first illumination condition A is calculated using a mathematical model. The calculated third illumination condition is determined as A′. The third illumination condition A′ is a virtual illumination condition under which the first pattern is transferred onto a substrate. Normally, the first illumination condition A and the virtual third illumination condition A′ do not perfectly match each other due to, for example, a resist image computation error and a deviation between the numerical definition of the illumination mode and the setting of an actual exposure apparatus. A virtual second illumination condition for reproducing the target pattern [Dimension Li; i=1, . . . , n] (a solid line in FIG. 1A) is calculated using a mathematical model. The calculated second illumination condition is determined as B′. The second illumination condition B′ is a virtual illumination condition under which the target pattern is transferred onto a substrate. The second illumination condition B′ can never match the illumination condition B which directly attains the target pattern due to, for example, a resist image computation error and a deviation between the numerical definition of the illumination mode and the setting of an actual exposure apparatus, as described above. The mathematical models used to calculate the virtual third illumination condition A′ and the second illumination condition B′ each are a model which defines the relationship between an illumination condition for model extraction, and a virtual pattern transferred onto a substrate using the illumination condition. An example of this model is a resist image computation model. Although the absolute value of a resist image computation error has no perfectly proportional relationship with a change in illumination condition, the difference in resist dimension has a proportional relationship with a minute change in illumination condition. Likewise, the difference in deviation between the numerical definition of the illumination mode and the setting of an actual exposure apparatus has a nearly proportional relationship with a change in illumination condition as long as this change is not so large. From the foregoing, the difference between the third illumination condition A′ and the second illumination condition B′ serves to eliminate these errors. Also, this difference equals a difference (Li−Mi) between the dimension Li of the target pattern transferred onto a substrate under the illumination condition B and the dimension Mi of the transfer pattern actually transferred under the first illumination condition A. Accordingly, this difference is accurately approximated by the dimensional difference between a virtual target pattern formed under the second illumination condition B′ and a virtual transfer pattern formed under the third illumination condition A′. Hence, a fourth illumination condition B under which the target pattern is transferred onto a substrate can be determined by adding the difference between the second illumination condition B′ and the third illumination condition A′ to the first illumination condition A. This is possible especially because the difference between the current transfer pattern and the target pattern and that between the current illumination condition and the illumination condition which attains the target pattern are not so large. A sequence of determining an illumination condition B under which a target pattern is transferred onto a substrate will be explained with reference to FIG. 1C. In step S11, a mathematical model used to obtain an illumination condition for reproducing a transfer pattern is constructed on the computer. Instead, a mathematical model may be constructed in advance separately. In this case, step S11 is omitted from the flowchart. In step S12, the computer sets a reticle target pattern to be transferred onto a substrate. In step S13, the computer obtains a first pattern formed by transferring the pattern of a reticle onto a substrate under the current first illumination condition A using the current exposure apparatus. In step S14, the computer obtains the result of measuring the dimension of the current transfer pattern (first pattern). In step S15, the computer calculates a virtual third illumination condition A′ for reproducing the current transfer pattern, based on the measured dimension of the current transfer pattern, using a mathematical model. The mathematical model can be, for example, a model which uses a genetic algorithm or a Monte Carlo algorithm. In step S16, the computer obtains/calculates a virtual second illumination condition B′ for reproducing the target pattern, based on the dimension of the target pattern, using a mathematical model. In step S17, the computer adds the difference between the second illumination condition B′ and the third illumination condition A′ to the first illumination condition A. The computer determines a fourth illumination condition B which satisfies A+(B′−A′) as the illumination condition under which the target pattern is transferred onto a substrate. A concrete example will be explained hereinafter. Reticle patterns used to form a transfer pattern and a target pattern are line-and-space patterns, as shown in FIG. 1B. A pattern group including nine types of patterns with a fixed line dimension of 100 nm and different line pitches (spaces) of 104 nm to 924 nm is selected, and annular illumination is adopted. Such evaluation is commonly called OPE (Optical Proximity Effect) evaluation. FIG. 2 illustrates an example of patterns used and the illumination condition optimization results. The outer σ (σ-out) and the ratio of the inner σ to the outer σ (σ-ratio) are used herein as parameters which describe annular illumination. FIG. 2 describes two graph lines. The lower graph line describes the OPE of the current transfer pattern, and its right side view shows a virtual third illumination condition for reproducing the current transfer pattern. In one embodiment, the third illumination condition is defined by σ-out=0.90 and σ-ratio=0.70. The upper graph line describes the OPE of the target pattern, and its upper side view shows a virtual second illumination condition for reproducing the target pattern. The second illumination condition is defined by σ-out=0.91 and σ-ratio=0.61. Each of these illumination conditions is calculated using a mathematical model. A fourth illumination condition under which the target pattern is transferred onto a substrate can be calculated by adding differences, between these two illumination conditions, Δσ-out=0.91−0.90=0.01 and Δσ-ratio=0.61−0.70=−0.09 to the current first illumination condition. The computer can execute a process for determining an illumination condition B, under which a target pattern is transferred onto a substrate, by storing a program for executing the process from step S12 to step S17 in a storage medium of the computer. Also, the computer can execute a process for determining an illumination condition B, under which a target pattern is transferred onto a substrate, by reading the program code from a recording medium which records the program. FIGS. 3A to 3D illustrate an example in which two-dimensional rectangular patterns are used as reticle patterns used to form a transfer pattern and a target pattern, and cross-pole illumination is adopted. This illumination exhibits a two-dimensional distribution shown in FIG. 3A, and exhibits an intensity distribution shown as a sectional view in FIG. 3B. In FIG. 3B, the abscissa indicates the position (r) in the radial direction in the illumination shown in FIG. 3A, and the ordinate indicates the intensity of the illumination. The intensity distribution herein approximately follows a Gaussian function. A central position a, width b, angular aperture (horizontal) Ψ1, and angular aperture (vertical) Ψ2 of the intensity distribution are used as parameters which describe the illumination. The left side view in FIG. 3C shows a transfer pattern (first pattern) transferred under the current first illumination condition. A virtual third illumination condition for reproducing the transfer pattern is defined by a=0.8, b=0.2, Ψ1=60, and Ψ2=60, as shown in FIG. 3A. The right side view in FIG. 3C shows a target pattern. FIG. 3D shows a virtual second illumination condition for reproducing the target pattern. The target pattern has central dimensions longer than those of the current transfer pattern by 4 nm and 6 nm, and other dimensions equal to those of the current transfer pattern. A virtual second illumination condition for reproducing the target pattern is defined by a=0.92, b=0.14, Ψ1=94, and Ψ2=77, as shown in FIG. 3D. Each of these illumination conditions is calculated using a mathematical model. Differences Δa, Δb, ΔΨ1, and ΔΨ2 between these two illumination conditions are calculated as:Δa=0.92−0.80=0.12Δb=0.14−0.20=−0.06ΔΨ1=94−60=34ΔΨ2=77−60=17 A fourth illumination condition under which the target pattern can be transferred onto a substrate can be determined by adding the obtained differences to the current illumination condition. Two virtual illumination conditions for reproducing the current transfer pattern and the target pattern can also be represented as bitmaps, and the difference between these illumination conditions can be obtained by subtraction of the bitmaps. In this case, however, a negative value may occur at a certain location in the bitmap obtained after the subtraction. After the subtraction result is added to the current first illumination condition, the location which bears the information of the subtraction result may, in turn, have a negative value. a negative value, which may result in errors, when the processing such as replacement with zero is used, which may result in errors. On the other hand, assume that two virtual illumination conditions for reproducing the current transfer pattern and the target pattern are represented by numeric values (parameters). In this case, these numeric values represent the overall illumination and are therefore less likely to generate a negative value when adding the differences to the current first illumination condition. Resist computation is used as a mathematical model for obtaining the contour of a transfer pattern herein. However, as in a linear pattern having densely populated evaluation points, when there is little difference between the results of optical computation and resist computation, optical image computation may be used in order to shorten the computation time. In the first embodiment, target patterns are set under one type of focus condition. These target patterns are normally set under a best focus condition. However, when an illumination condition for reproducing the target pattern on the premise of a best focus condition is used under a defocus condition, this may lead to a large deviation from the target pattern. To prevent this, in a second embodiment, an illumination condition is detected which allows the defocus amount to have a wide range in which a deviation from the contour of the target pattern falls within an allowable range. FIG. 4 describes graph lines (alternate long and short dashed lines) that fall within a certain allowable range of a dimension error from a target pattern in the upper and lower vicinities of a graph line, which describes a targeted transfer pattern, indicated by a solid line. An illumination condition which allows the target pattern to fall within the range indicated by alternate long and short dashed lines is detected. Note that in FIG. 4, the current transfer pattern is indicated by a dotted line. A method of detecting an illumination condition which allows the defocus amount to have a wide range is as follows. A transfer pattern is calculated for each illumination condition being detected in an optimization method. The RMS of the differences from the target dimension values (a solid line in FIG. 4) at respective evaluation points is computed. The defocus characteristic of the RMS value is calculated and graphed. The range of the defocus amount (DOF), in which the RMS is smaller than a predetermined value, is calculated. The illumination condition is optimized such that the calculated DOF value is maximum. FIG. 5 shows the optimization result obtained by setting only the dimension value under a best focus condition as a target, and that obtained by taking account of defocus. The RMS in illumination a is small under a best focus condition, but increases with an increase in defocus. In contrast to this, the RMS in illumination b is larger than that in the illumination a under a best focus condition, but increases more moderately with an increase in defocus than in the illumination a. Whether to select the illumination a or b is determined based on whether a process of manufacturing a device gives priority to a high-precision operation with a narrow manufacturing margin or with a wide manufacturing margin. Since a wide manufacturing margin is generally of greater importance, the illumination b which allows defocus to have a wide range is selected in many cases. In the first embodiment, the patterning result of a targeted transfer pattern obtained under one type of focus condition is taken into consideration. However, in a third embodiment, an illumination condition which attains a target pattern is determined by referring to the patterning results of a certain targeted transfer pattern obtained under a plurality of different focus conditions. FIG. 6 shows the patterning results of an OPE evaluation pattern obtained under a best focus condition and a 60-nanometer defocus condition. Each of these two conditions yield two transfer results: the transfer result obtained under an illumination condition for reproducing the current transfer pattern, and that obtained under an illumination condition for reproducing the target pattern. Based on these transfer results, the illumination condition is optimized. FIG. 7 shows transfer patterns obtained under the illumination condition determined by taking account of the transfer results of a two-dimensional pattern obtained under a best focus condition and a 60-nanometer defocus condition. Because it is hard to visually check the dimensional difference between the two-dimensional patterns corresponding to a best focus condition and a defocus condition, FIG. 7 numerically describes that dimensional difference. A case in which a conceptual method as in the first embodiment is performed by OPE evaluation will be explained in a fourth embodiment. First, a difference Δi between a dimension Li (i=1, . . . , n) of a target pattern and a dimension Mi of the current transfer pattern (first pattern) is calculated for each evaluation point. In FIG. 8A, Δi is indicated by a vertical line. A resist image of a virtual transfer pattern (second pattern) transferred under a first illumination condition A used currently is computed, and the dimension at each evaluation point is determined as Ni. Ni has a value slightly different from Mi due to, for example, a resist computation error and a deviation between the numerical definition of the illumination mode and the setting of an actual exposure apparatus. Next, Pi=Ni+Δi is calculated. FIG. 8B describes Pi and Ni. The length of a vertical line indicated by Δi in FIG. 8B is equal to that of a vertical line indicated by Δi in FIG. 8A. A virtual fifth illumination condition B for reproducing a virtual target pattern is obtained by adopting the above-mentioned mathematical model assuming that the third pattern having the dimension Pi as a virtual target pattern. The dimension Pi of the virtual target pattern is different from the dimension Li of the target pattern. This is accounted for by, for example, a resist computation error generated between actual patterning and simulation, and a deviation between the numerical definition of the illumination mode and the setting of an actual exposure apparatus. The practical application of the fifth illumination condition B optimized in order to reproduce the virtual target pattern having the dimension Pi cancels the above-mentioned errors and therefore leads to a correct result. FIG. 8C is a flowchart showing a sequence of determining a fifth illumination condition B which attains a virtual target pattern (third pattern). Steps S21 to S24 are the same as steps S11 to S14, respectively in FIG. 1C, and a description thereof will not be given. In step S25, the computer calculates a difference Δi=Li−Mi between a dimension Li of the target pattern and a dimension Mi of the current transfer pattern (first pattern) at each of a plurality of evaluation points. In step S26, the computer calculates, by resist computation, a dimension Ni of a virtual transfer pattern (second pattern) transferred under the current first illumination condition A. In step S27, the computer adds the difference Δi to the dimension Ni of the virtual transfer pattern (second pattern) to calculate Ni+Δi=Pi, where Pi is the dimension of a virtual target pattern (third pattern). In step S28, using a mathematical model, the computer calculates a fifth illumination condition B for reproducing the virtual targeted transfer pattern (third pattern) having the dimension Pi. Step S26 is a second calculation step of calculating a virtual second pattern, and step S28 is a third calculation step of calculating a virtual fifth illumination condition. The mathematical model can be, for example, a model which includes a genetic algorithm or a Monte Carlo algorithm. In step S29, the computer determines the fifth illumination condition B as the illumination condition under which the target pattern is transferred onto a substrate. A program for executing the process from step S22 to step S29 can be stored in a storage medium of the computer. With this operation, the computer can execute a process for determining the illumination condition under which a target pattern is transferred onto a substrate from step S22 to step S29. Also, the computer can execute the process for determining the illumination condition by reading the program code from a recording medium which records the program. The fourth embodiment can similarly adopt the following methods described in the second and third embodiments: a method of detecting an illumination condition which allows the defocus amount to have a wide range in which a targeted transfer pattern falls within a certain dimensional allowance; and a method of referring to the results of transferring one transfer pattern under a plurality of focus conditions. In the second to fourth embodiments, illumination allowing the defocus amount to have a wide range in which a target pattern falls within a certain dimensional allowance is detected. In a fifth embodiment, an illumination condition that allows both the exposure amount and the focus to have a wide allowable range (commonly called a window) is detected. One method is to calculate a region where an error from the target dimension falls within an allowable range in a two-dimensional space defined by the exposure amount and the focus, and optimize the illumination condition such that the calculated region has a maximum area, as shown in FIG. 9. Alternatively, in one application example of the fifth embodiment, an illumination condition allowing the exposure amount to have a wide range in which a dimension error falls within an allowable range may be detected. In the third embodiment, an optimum illumination condition is determined by referring to the results of transferring one transfer pattern under a plurality of focus conditions. Instead, the illumination condition can also be determined by referring to the transfer results obtained using a plurality of exposure amounts in place of a plurality of focus conditions. An exemplary method of manufacturing devices such as a semiconductor integrated circuit device and a liquid crystal display device will be explained next. The devices are manufactured by an exposure step of exposing a substrate using the illumination condition determined using the above-mentioned determining method, a development step of developing the substrate exposed in the exposure step, and known subsequent steps of processing the substrate developed in the development step. The known subsequent steps include, for example, etching, resist removal, dicing, bonding, and packaging steps. While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. This application claims the benefit of Japanese Patent Application No. 2008-278611, filed Oct. 29, 2008, which is hereby incorporated by reference herein in its entirety. |
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description | This application is: a Continuation of pending U.S. application Ser. No. 11/956,610 filed 14 Dec. 2007, which claims the benefit of U.S. Application 60/875,211, filed 15 Dec. 2006; and a Continuation-In-Part of U.S. application Ser. No. 11/602,836, filed 21 Nov. 2006, now U.S. Pat. No. 7,411,204, which is: a Continuation of U.S. application Ser. No. 10/308,545 filed 3 Dec. 2002, now U.S. Pat. No. 7,141,812, which is: a Continuation-In-Part of U.S. application Ser. No. 10/282,441 filed 29 Oct. 2002, now U.S. Pat. No. 7,518,136; a Continuation-In-Part of U.S. application Ser. No. 10/282,402 filed 29 Oct. 2002, now U.S. Pat. No. 7,462,852; and a Continuation-In-Part of International Application PCT/US02/17936 filed 5 Jun. 2002, which claims the benefit of U.S. Application 60/339,773 filed 17 Dec. 2001 and U.S. Application 60/295,564 filed 5 Jun. 2001. A wide variety of potential practical and useful embodiments will be more readily understood through the following detailed description of certain exemplary embodiments, with reference to the accompanying exemplary drawings in which: FIG. 1 is a flowchart of an exemplary method; FIG. 2 is a flow diagram of exemplary items fabricated using an exemplary method; FIG. 3 is a perspective view of an exemplary casting that illustrates aspect ratio; FIG. 4 is an assembly view of an exemplary assembly; FIG. 5A is a top view of an exemplary stack lamination mold; FIGS. 5B-5E are exemplary alternative cross-sectional views of an exemplary stack lamination mold taken at section lines 5-5 of FIG. 5A; FIG. 6 is an unassembled cross-sectional view of an alternative exemplary stack lamination mold taken at section lines 5-5 of FIG. 5A; FIG. 7 is a cross-sectional view of an exemplary alternative stack lamination mold taken at section lines 5-5 of FIG. 5A; FIG. 8 is a perspective view of an exemplary laminated mold; FIG. 9 is a cross-section of an exemplary mold taken along lines 9-9 of FIG. 8; FIG. 10A is a top view an exemplary layer having a redundant array of shapes; FIG. 10B is a top view of an exemplary layer having a non-redundant collection of shapes; FIG. 11 is a top view of an exemplary stacked lamination mold; FIG. 12 is a cross-sectional view of an exemplary mold taken at section lines 12-12 of FIG. 11; FIG. 13 is a side view of an exemplary cast part formed using the exemplary mold of FIG. 11; FIG. 14 is a top view of an exemplary laminated mold; FIG. 15 is a cross-sectional view of an exemplary mold taken at section lines 15-15 of FIG. 14; FIG. 16 is a perspective view of an exemplary cast part formed using the exemplary mold of FIG. 14; FIG. 17 is a top view of an exemplary planar laminated mold having an array of openings; FIG. 18 is a top view of an exemplary flexible casting or mold insert molded using the laminated mold of FIG. 17; FIG. 19 is a top view of an exemplary mold fixture; FIG. 20 is a top view of an exemplary planar laminated mold; FIG. 21 is a top view of an exemplary flexible casting or mold insert molded using the laminated mold of FIG. 20; FIG. 22 is a top view of an exemplary mold fixture; FIG. 23 is a perspective view of an exemplary laminated mold; FIG. 24 is a close-up perspective view of an exemplary single cylindrical cavity of an exemplary mold; FIG. 25 is a perspective view of an exemplary cast part; FIG. 26 is a flowchart of an exemplary method; FIG. 27 is a perspective view of a plurality of exemplary layers; FIG. 28 is a perspective view of an exemplary laminating fixture; FIG. 29 is a top view of stack lamination mold that defines an array of cavities; FIG. 30 is a cross-section of a cavity taken along section lines 30-30 of FIG. 29; FIG. 31 is a perspective view of an exemplary single corrugated feedhorn; FIG. 32 is a side view of an exemplary casting fixture; FIG. 33 is a side view of an exemplary section of cylindrical tubing that demonstrates the shape of an exemplary fluidic channel; FIG. 34 is a top view of an exemplary micro-machined layer; FIG. 35 is a cross-sectional view of a laminated slit taken along section lines 35-35 of FIG. 34; FIG. 36 is a side view of a portion of an exemplary flexible cavity insert; FIG. 37 is a top view of an exemplary base plate; FIG. 38 is a front view of a single exemplary flexible cavity insert assembly; FIG. 39 is a front view of flexible cavity inserts; FIG. 40 is a top view of a top plate; FIG. 41 is a flowchart of an exemplary embodiment of a method; FIG. 42A is a top view of an exemplary laminated stack; FIG. 42B is a cross-sectional view, taken at section lines 42-42 of FIG. 42A, of an exemplary laminated stack; FIG. 43 is side view of an exemplary mold and casting; FIG. 44 is a top view of an exemplary casting fixture; FIG. 45 is a front view of the exemplary casting fixture of FIG. 44; FIG. 46 is a top view of a portion of an exemplary grid pattern; FIG. 47 is an assembly view of components of an exemplary pixilated gamma camera; FIG. 48A is a top view of an array of generic microdevices; FIG. 48B is a cross-sectional view of an exemplary microdevice, taken at section lines 48-48 of FIG. 48A, in the open state; FIG. 49 is a cross-sectional view of the exemplary microdevice of FIG. 48B, taken at section lines 48-48 of FIG. 48A, in the closed state; FIG. 50 is a cross-sectional view of an alternative exemplary microdevice, taken at section lines 48-48 of FIG. 48A, and shown with an inlet valve open; FIG. 51 is a cross-sectional view of the alternative exemplary microdevice of FIG. 50, taken at section lines 48-48 of FIG. 48A, and shown with an outlet valve open; FIG. 52 is a top view of an exemplary microwell array; FIG. 53 is a cross-sectional view taken at lines 52-52 of FIG. 52 of an exemplary microwell; FIG. 54 is a cross-sectional view taken at lines 52-52 of FIG. 52 of an alternative exemplary microwell; FIG. 55 is a top view of exemplary microwell; FIG. 56 is a cross-sectional view of an exemplary microwell, taken at lines 55-55 of FIG. 55; FIG. 57 illustrates an exemplary embodiment of a microstructure derived from a finite element analysis (FEA) and formed via an exemplary method described herein; FIG. 58 is a perspective view of an exemplary embodiment of opposing interlocking microstructures formed via an exemplary method described herein; FIG. 59 is a perspective view of an exemplary embodiment of a lattice microstructure formed via an exemplary method described herein; FIG. 60 is a perspective view of an exemplary embodiment of a composite microstructure formed via an exemplary method described herein; FIG. 61 is a flowchart of an exemplary embodiment of a basic sequence of an exemplary method described herein; FIG. 62 is a block diagram of an exemplary embodiment of a basic sequence of an exemplary method described herein; FIG. 63 is a perspective view of an exemplary embodiment of a simplified microstructure formed via an exemplary method described herein; FIG. 64 is a perspective view of an exemplary embodiment of a macro-scale surface comprising a plurality of microstructures, the surface and microstructures formed via an exemplary method described herein; FIG. 65 is a photomicrograph of exemplary columnar microstructures formed via an exemplary method described herein; FIG. 66 is a photomicrograph of exemplary cast microstructures formed via an exemplary method described herein; FIG. 67 is a photomicrograph of an exemplary 7-layer microstructure formed via an exemplary method described herein; FIG. 68 is a photomicrograph of an exemplary array of microstructures formed via an exemplary method described herein; FIG. 69 is a photomicrograph of a surface of an exemplary microstructure formed via an exemplary method described herein; FIG. 70 illustrates some exemplary embodiments of tessellation; FIG. 71 illustrates some exemplary embodiments of fractal patterns; FIG. 72 illustrates an exemplary output of an exemplary finite element analysis; FIG. 73 shows a perspective view of an exemplary isogrid structure; FIG. 74 is a perspective view of an exemplary embodiment of an isogrid 74000. FIG. 75A and FIG. 75B are a top and side views, respectively of an exemplary embodiment of a male interlocking isogrid 75100; FIG. 75C and FIG. 75D are a top and side views, respectively of an exemplary embodiment of a female interlocking isogrid 75200; and FIG. 76 is a block diagram of an exemplary embodiment of an information device 76000. FIG. 77A is a top view of an exemplary embodiment of a system 77000 comprising an isogrid tiling positioner. FIG. 77B is a front view of an exemplary embodiment of the system 77000 of FIG. 77A. FIG. 78A is a top view of an exemplary embodiment of a system 78000 comprising an channeled isogrid. FIG. 78B is a front view of an exemplary embodiment of the system 78000 of FIG. 78A. FIG. 79A is a top view of an exemplary embodiment of a system 79000 comprising an isogrid attached to a face plate. FIG. 79B is a front view of an exemplary embodiment of system 79000 of FIG. 79A. FIG. 79C is a front view of an exemplary embodiment of system 79000 of FIG. 79A. FIG. 80A is a top view of an exemplary embodiment of a system 80000 comprising an isogrid stacking positioner. FIG. 80B is a front view of an exemplary embodiment of system 80000 of FIG. 80A. FIG. 80C is a front view of an exemplary embodiment of system 80000 of FIG. 80A. FIG. 81A is a top view of an exemplary embodiment of a system 81000 comprising an isogrid stacking positioner. FIG. 81B is a front view of an exemplary embodiment of system 81000 of FIG. 81A. FIG. 82A is a top view of an exemplary embodiment of a system 82000 comprising an isogrid stacking positioner. FIG. 82B is a front view of an exemplary embodiment of system 82000 of FIG. 82A. FIG. 82C is a front view of an exemplary embodiment of system 82000 of FIG. 82A. FIG. 83A is a top view of an exemplary embodiment of a system 83000 comprising a fillet joining two ligaments at a node. FIG. 83B is a front view of an exemplary embodiment of system 83000 of FIG. 83A. FIG. 84 is a top view of an exemplary embodiment of a system 84000 comprising a substantially circular node. FIG. 85 is a top view of an exemplary embodiment of a system 85000 comprising an isogrid tiling positioner. FIG. 86 is a top view of an exemplary embodiment of a system 86000 comprising an interlocking isogrid tiling positioner. Certain exemplary embodiments can combine certain techniques of stack lamination with certain molding processes to manufacture a final product. As a result of the stack lamination techniques, precision micro-scale cavities of predetermined shapes can be engineered into the stack lamination. Rather than have the stack lamination embody the final product, however, the stack lamination can be used as an intermediate in a casting or molding process. In certain exemplary embodiments, the stack lamination (“laminated mold”) can be made up of layers comprising metallic, polymeric, and/or ceramic material. The mold can be a positive replication of a predetermined end product or a negative replication thereof. The mold can be filled with a first cast material and allowed to solidify. A first cast product can be demolded from the mold. The first cast material can comprise a flexible polymer such as silicone rubber. Certain exemplary embodiments of a method can further include surrounding the first cast product with a second casting material and allowing the second cast material to solidify. Still further, a second cast product can be demolded from the first cast product. Some exemplary embodiments can further include positioning an insert into the cavity prior to filling the mold with the first cast material, wherein the insert occupies only a portion of the space defined by the cavity. The second cast product can be nonplanar. The end product and/or the mold cavity can have an aspect ratio greater that 100:1. The end product can be attached to the substrate or it can be a free-standing structure. In certain exemplary embodiments, the master mold can be fabricated using diverse micro-machining methods, which can allow hybrid integration of various disciplines. In certain exemplary embodiments, the master mold can be fabricated using high-precision lithographic techniques, which can allow production of accurate molds, castings, and features having virtually any shape. In certain exemplary embodiments, layers for master mold fabrication can be produced by using low cost materials and low cost manufacturing methods such as photo-chemical machining. In certain exemplary embodiments, the layers used for master mold fabrication can have sub-cavities with controlled depths and shapes. These cavities can be used to produce integrated micro-features in cast objects. In certain exemplary embodiments, the master molds can be produced over large areas. This allows the production of large batches of cast micro-devices or large macro devices with incorporated arrays of micro features. In certain exemplary embodiments, master molds and castings can be produced having extremely high-aspect ratios. Aspect ratio's greater than 400:1 can be achieved using photo-chemical machining combined with precision stack lamination. In certain exemplary embodiments, hundreds to thousands of individual structures can be batch produced simultaneously, eliminating the need to produce 3D micro-structures one at a time. In certain exemplary embodiments, many diverse materials can be used to create advanced molds and/or cast devices. This can greatly enhance design and fabrication opportunities for low cost, application specific devices. Materials can include, but are not limited to, polymers, epoxy resins, polyesters, acrylics, ceramics, powder metals, castable metals, urethanes, silicon, and/or rubber etc. Materials can also be integrated for production of “smart” materials needed for fabricating advanced MEMS devices. Smart materials would include those having functional properties such as for example conductivity, electrostrictivity, piezoelectricity, magnetic, elastic, thermal, density, and/or chemical resistivity, etc. In certain exemplary embodiments, the micro devices and/or structures can be produced as free form or attached structures. This can be achieved through molding and casting designs or through secondary machining techniques. In certain exemplary embodiments, micro devices can be produced outside of clean room facilities, thereby potentially lowering production overhead costs. In certain exemplary embodiments, by using lithographic techniques for producing master molds and/or micro devices, arrays of devices or micro features can be accurately integrated and aligned with standard microelectronics. In certain exemplary embodiments, through the fabrication method used for producing the master molds, highly accurate, three dimensional engineering and production of micro scale devices can be possible. In certain exemplary embodiments, through the use of flexible molds, highly accurate, three dimensional engineering and production of non-planar, micro scale devices is possible. Non-planar shapes can include, but are not limited to, curves, arcs, diameters, spherical radii, inside and outside diameters of cylinders, etc. FIG. 1 is a flowchart of an exemplary embodiment of a method 1000. At activity 1010, a mold design is determined. At activity 1020, the layers of the mold (“laminations”) are fabricated. At activity 1030, the laminations are stacked and assembled into a mold (a derived mold could be produced at this point as shown in FIG. 1). At activity 1060, a first casting is cast. At activity 1070, the first casting is demolded. FIG. 2 is a flow diagram of exemplary items fabricated during a method 2000. Layers 2010 can be stacked to form a mold or stacked lamination 2020. A molding or casting material can be applied to mold 2020 to create a molding or casting 2030, that can be demolded from mold 2020. FIG. 3 is a perspective view of an exemplary molding 3000 that demonstrates a parameter referred to herein as “aspect ratio” which is described below. Molded block 3010 has numerous through-holes 3020, each having a height H and a diameter or width W. For the purposes of this application, aspect ratio is defined as the ratio of height to width or H/W of a feature, and can apply to any “negative” structural feature, such as a space, channel, through-hole, cavity, etc., and can apply to a “positive” feature, such as a wall, projection, protrusion, etc., with the height of the feature measured along the Z-axis. Note that all features can be “bordered” by at least one “wall”. For a positive feature, the wall is part of the feature. For a negative feature, the wall at least partially defines the feature. FIG. 3 also demonstrates the X-, Y-, and Z-directions or axes. For the purposes of this application, the dimensions measured in the X- and Y-directions define a top surface of a structure (such as a layer, a stack lamination mold, or negative and/or positive replications thereof) when viewed from the top of the structure. The Z-direction is the third dimension perpendicular to the X-Y plane, and corresponds to the line of sight when viewing a point on a top surface of a structure from directly above that point. Certain embodiments of a method can control aspect ratios for some or all features in a laminated mold, derived mold, and/or cast item (casting). The ability to attain relatively high aspect ratios can be affected by a feature's geometric shape, size, material, and/or proximity to another feature. This ability can be enhanced using certain embodiments. For example, through-features of a mold, derived mold, and/or final part, having a width or diameter of approximately 5 microns, can have a dimension along the Z axis (height) of approximately 100 microns, or approximately 500 microns, or any value in the range there between (implying an aspect ratio of approximately 20:1, 100:1, or any value in the range therebetween, including, for example: 20:1 to 30:1, 20:1 to 40:1, 20:1 to 50:1, 20:1 to 60:1, 20:1 to 70:1, 20:1 to 80:1, 20:1 to 90:1, 20:1 to 100:1, 30:1 to 40:1, 30:1 to 50:1, 30:1 to 60:1, 30:1 to 70:1, 30:1 to 80:1, 30:1 to 90:1, 30:1 to 100:1, 40:1 to 50:1, 40:1 to 60:1, 40:1 to 70:1, 40:1 to 80:1, 40:1 to 90:1, 40:1 to 100:1, 50:1 to 60:1, 50:1 to 70:1, 50:1 to 80:1, 50:1 to 90:1, 50:1 to 100:1, 60:1 to 70:1, 60:1 to 80:1, 60:1 to 90:1, 60:1 to 100:1, 70:1 to 80:1, 70:1 to 90:1, 70:1 to 100:1, 80:1 to 90:1, 80:1 to 100:1, etc). As another example, a through slit having a width of approximately 20 microns can have a height of approximately 800 microns, or approximately 1600 microns, or any value in the range therebetween (implying an aspect ratio of approximately 40:1, 80:1, or any value in the range therebetween, including, for example: 40:1 to 50:1, 40:1 to 60:1, 40:1 to 70:1, 40:1 to 80:1, 50:1 to 60:1, 50:1 to 70:1, 50:1 to 80:1, 60:1 to 70:1, 60:1 to 80:1, 70:1 to 80:1, etc). As yet another example, the same approximately 20 micron slit can be separated by an approximately 15 micron wide wall in an array, where the wall can have a dimension along the Z axis (height) of approximately 800 microns, or approximately 1600 microns, or any value in the range therebetween (implying an aspect ratio of approximately 53:1, 114:1, or any value in the range therebetween, including, for example: 53:1 to 60:1, 53:1 to 70:1, 53:1 to 80:1, 53:1 to 90:1, 53:1 to 100:1, 53:1 to 110:1, 53:1 to 114:1, 60:1 to 70:1, 60:1 to 80:1, 60:1 to 90:1, 60:1 to 100:1, 60:1 to 110:1, 60:1 to 114:1, 70:1 to 80:1, 70:1 to 90:1, 70:1 to 100:1, 70:1 to 110:1, 70:1 to 114:1, 80:1 to 90:1, 80:1 to 100:1, 90:1 to 110:1, 90:1 to 114:1, 90:1 to 100:1, 90:1 to 110:1, 90:1 to 114:1, 100:1 to 110:1, 100:1 to 114:1, etc.). Still another example is an array of square-shaped openings having sides that are approximately 0.850 millimeters wide, each opening separated by approximately 0.150 millimeter walls, with a dimension along the Z axis of approximately 30 centimeters. In this example the approximately 0.850 square openings have an aspect ratio of approximately 353:1, and the approximately 0.150 walls have an aspect ratio of approximately 2000:1, with lesser aspect ratios possible. Thus, the aspect ratio of the openings can be approximately 10:1, or approximately 350:1, or any value in the range therebetween, including for example: 10:1 to 20:1, 10:1 to 30:1, 10:1 to 40:1, 10:1 to 50:1, 10:1 to 60:1, 10:1 to 70:1, 10:1 to 80:1, 10:1 to 90:1, 10:1 to 100:1, 10:1 to 150:1, 10:1 to 200:1, 10:1 to 250:1, 10:1 to 300:1, 10:1 to 350:1, 20:1 to 30:1, 20:1 to 40:1, 20:1 to 50:1, 20:1 to 60:1, 20:1 to 70:1, 20:1 to 80:1, 20:1 to 90:1, 20:1 to 100:1, 20:1 to 150:1, 20:1 to 200:1, 20:1 to 250:1, 20:1 to 300:1, 20:1 to 350:1, 30:1 to 40:1, 30:1 to 50:1, 30:1 to 60:1, 30:1 to 70:1, 30:1 to 80:1, 30:1 to 90:1, 30:1 to 100:1, 30:1 to 150:1, 30:1 to 200:1, 30:1 to 250:1, 30:1 to 300:1, 30:1 to 350:1, 40:1 to 50:1, 40:1 to 60:1, 40:1 to 70:1, 40:1 to 80:1, 40:1 to 90:1, 40:1 to 100:1, 40:1 to 150:1, 40:1 to 200:1, 40:1 to 250:1, 40:1 to 300:1, 40:1 to 350:1, 50:1 to 60:1, 50:1 to 70:1, 50:1 to 80:1, 50:1 to 90:1, 50:1 to 100:1, 50:1 to 150:1, 50:1 to 200:1, 50:1 to 250:1, 50:1 to 300:1, 50:1 to 350:1, 75:1 to 80:1, 75:1 to 90:1, 75:1 to 100:1, 75:1 to 150:1, 75:1 to 200:1, 75:1 to 250:1, 75:1 to 300:1, 75:1 to 350:1, 100:1 to 150:1, 100:1 to 200:1, 100:1 to 250:1, 100:1 to 300:1, 100:1 to 350:1, 150:1 to 200:1, 150:1 to 250:1, 150:1 to 300:1, 150:1 to 350:1, 200:1 to 250:1, 200:1 to 300:1, 200:1 to 350:1, 250:1 to 300:1, 250:1 to 350:1, 300:1 to 350:1, etc. Moreover, the aspect ratio of the walls can be approximately 10:1, or approximately 2000:1, or any value in the range therebetween, including for example: 10:1 to 20:1, 10:1 to 30:1, 10:1 to 40:1, 10:1 to 50:1, 10:1 to 100:1, 10:1 to 200:1, 10:1 to 500:1, 10:1 to 1000:1, 10:1 to 2000:1, 20:1 to 30:1, 20:1 to 40:1, 20:1 to 50:1, 20:1 to 100:1, 20:1 to 200:1, 20:1 to 500:1, 20:1 to 1000:1, 20:1 to 2000:1, 30:1 to 40:1, 30:1 to 50:1, 30:1 to 100:1, 30:1 to 200:1, 30:1 to 500:1, 30:1 to 1000:1, 30:1 to 2000:1, 40:1 to 50:1, 40:1 to 100:1, 40:1 to 200:1, 40:1 to 500:1, 40:1 to 1000:1, 40:1 to 2000:1, 50:1 to 100:1, 50:1 to 200:1, 50:1 to 500:1, 50:1 to 1000:1, 50:1 to 2000:1, 100:1 to 200:1, 100:1 to 500:1, 100:1 to 1000:1, 100:1 to 2000:1, 200:1 to 500:1, 200:1 to 1000:1, 200:1 to 2000:1, 500:1 to 1000:1, 500:1 to 2000:1, 1000:1 to 2000:1, etc. Another example of aspect ratio is the space between solid (positive) features of a mold, derived mold, and/or casting. For example, as viewed from the top, a casting can have two or more solid rectangles measuring approximately 50 microns wide by approximately 100 microns deep with an approximately 5 micron space therebetween (either width-wise or depth-wise). The rectangles can have a height of 100 microns, or 500 microns, or any value in the range therebetween (implying an aspect ratio of 20:1, or 100:1, or any value therebetween, including, for example: 20:1 to 30:1, 20:1 to 40:1, 20:1 to 50:1, 20:1 to 60:1, 20:1 to 70:1, 20:1 to 80:1, 20:1 to 90:1, 20:1 to 100:1, 30:1 to 40:1, 30:1 to 50:1, 30:1 to 60:1, 30:1 to 70:1, 30:1 to 80:1, 30:1 to 90:1, 30:1 to 100:1, 40:1 to 50:1, 40:1 to 60:1, 40:1 to 70:1, 40:1 to 80:1, 40:1 to 90:1, 40:1 to 100:1, 50:1 to 60:1, 50:1 to 70:1, 50:1 to 80:1, 50:1 to 90:1, 50:1 to 100:1, 60:1 to 70:1, 60:1 to 80:1, 60:1 to 90:1, 60:1 to 100:1, 70:1 to 80:1, 70:1 to 90:1, 70:1 to 100:1, 80:1 to 90:1, 80:1 to 100:1, etc). In another example the same rectangles can have a space there between of approximately 20 microns, and the rectangles can have dimensions along the Z axis of approximately 800 microns, or approximately 5000 microns, or any value therebetween (implying an aspect ratio of approximately 40:1, or 250:1, or any value therebetween, including, for example: 40:1 to 50:1, 40:1 to 75:1, 40:1 to 100:1, 40:1 to 150:1, 40:1 to 200:1, 40:1 to 250:1, 75:1 to 100:1, 75:1 to 150:1, 75:1 to 200:1, 75:1 to 250:1, 100:1 to 150:1, 100:1 to 200:1, 100:1 to 250:1, 150:1 to 200:1, 150:1 to 250:1, 200:1 to 250:1, etc). FIG. 4 is an assembly view of an exemplary assembly 4000 that includes mold 4010 and cast part 4020 formed from mold 4010. Because certain exemplary embodiments can utilize lithographically-derived micro-machining techniques (or in some cases, non-lithographically-derived micro-machining techniques, such as laser machining) combined with molding and/or casting, laminated molds can be conceived as negatives 4010 or positives 4020 of the desired end product. The terms “negative” or “positive” replications can be subjective terms assigned to different stages of reaching an end product. For certain embodiments, any intermediate or the end product can be considered a negative or positive replication depending on a subject's point of view. For the purpose of this application, a “positive’ replication is an object (whether an intermediate or an end product) that geometrically resembles at least a portion of the spatial form of the end product. Conversely, a “negative” replication is a mold that geometrically defines at least a portion of the spatial form of the end product. The following parameters are described for the purpose of demonstrating some of the potential design parameters of certain embodiments of a method. Layer Thickness One design parameter can be the thickness of the micro-machined layers of the stack lamination mold. According to certain exemplary embodiments, to achieve high-aspect ratios, multiple micro-machined foils or layers can be stacked in succession and bonded together. In certain exemplary embodiments, the layer thickness can have a dimensional role in creating the desired shape in the third dimension. FIG. 5A is a top view of an exemplary stack lamination mold 5000. FIGS. 5B-5E are exemplary alternative cross-sectional views of exemplary stack lamination mold 5000 taken at section lines 5-5 of FIG. 5A. As shown in FIG. 5B and FIG. 5D, respectively, stacks 5010 and 5020 utilize relatively thick layers. As shown in FIG. 5C and FIG. 5E, respectively, stacks 5030 and 5040 utilize relatively thinner layers in succession to smooth out resolution along the z-axis. Specific layers can have multiple functions that can be achieved through their thickness or other incorporated features described herein. Cross-Sectional Shape of Layer One design parameter can be the cross sectional shape of a given layer in the mold. Through the use of etching and/or deposition techniques, many cross sectional shapes can be obtained. FIG. 6 is an unassembled cross-sectional view of an alternative exemplary stack lamination mold 5000 taken at section lines 5-5 of FIG. 5A. Each of exemplary layers 6010, 6020, 6030, and 6040 of FIG. 6 define an exemplary through-feature 6012, 6022, 6032, 6042, respectively, each having a different shape, orientation, and/or configuration. These through-features 6012, 6022, 6032, 6042 are bordered by one or more “sidewalls” 6014, 6024, 6034, and 6044, respectively, as they are commonly referred to in the field of lithographic micro-machining. Etching disciplines that can be utilized for a layer of the mold can be broadly categorized as isotropic (non-linear) or anisotropic (linear), depending on the shape of the remaining sidewalls. Isotropic often refers to those techniques that produce one or more radial or hour glassed shaped sidewalls, such as those shown in layer 6010. Anisotropic techniques produce one or more sidewalls that are more vertically straight, such as those shown in layer 6020. Additionally, the shape of a feature that can be etched through a foil of the mold can be controlled by the depth of etching on each surface and/or the configuration of the photo-mask. In the case of photo-chemical-machining, a term such as 90/10 etching is typically used to describe the practice of etching 90% through the foil thickness, from one side of the foil, and finishing the etching through the remaining 10% from the other side, such as shown on layer 6030. Other etch ratios can be obtained, such as 80/20, 70/30, and/or 65/35, etc., for various foils and/or various features on a given foil. Also, the practice of displacing the positional alignment of features from the top mask to the bottom mask can be used to alter the sidewall conditions for a layer of the mold, such as shown in layer 6040. By using these and/or other specific conditions as design parameters, layers can be placed to contribute to the net shape of the 3-dimensional structure, and/or provide specific function to that region of the device. For example, an hourglass sidewall could be used as a fluid channel and/or to provide structural features to the device. FIG. 7 is a cross-sectional view of an alternative exemplary stack lamination mold taken at section line 5-5 of FIG. 5A. FIG. 7 shows a laminated mold 5000 having layers 7010, 7020, 7030, 7040 that define cavity 7060. To achieve this, layers 7010, 7020 are etched anisotropically to have straight sidewalls, while layer 7030 is thicker than the other layers and is etched isotropically to form the complex shaped cross-section shown. Cross-Sectional Surface Condition of Layer Another design parameter when creating advanced three-dimensional structures can be the cross-sectional surface condition of the layers used to create a laminated mold. As is the case with sidewall shape, surface condition can be used to provide additional function to a structure or a particular region of the structure. FIG. 8 is a perspective view of a generic laminated mold 8000. FIG. 9 is a cross-section of mold 8000 taken at lines 9-9 of FIG. 8. Any sidewall surface, top or bottom surface can be created with one or more specific finish conditions on all layers or on selected layers, such as for example, forming a relatively rough surface on at least a portion of a sidewall 9100 of certain through-features 9200 of layer 9300. As another example, chemical and/or ion etching can be used to produce very smooth, polished surfaces through the use of selected materials and/or processing techniques. Similarly, these etching methods can also be manipulated to produce very rough surfaces. Secondary techniques, such as electro-plating and/or passive chemical treatments can also be applied to micromachined surfaces (such as a layer of the mold) to alter the finish. Certain secondary techniques (for example, lapping or superfinishing) can also be applied to non-micromachined surfaces, such as the top or bottom surfaces of a layer. In any event, using standard profile measuring techniques, described as “roughness average” (Ra) or “arithmetic average” (AA), the following approximate ranges for surface finish (or surface conditions) are attainable using micromachining and/or one or more secondary techniques according to certain embodiments (units in microns): 50 to any of: 25, 12.5, 6.3, 3.2, 1.6, 0.80, 0.40, 0.20, 0.10, 0.050, 0.025, 25 to any of: 12.5, 6.3, 3.2, 1.6, 0.80, 0.40, 0.20, 0.10, 0.050, 0.025, 12.5 to any of: 6.3, 3.2, 1.6, 0.80, 0.40, 0.20, 0.10, 0.050, 0.025, 6.3 to any of: 3.2, 1.6, 0.80, 0.40, 0.20, 0.10, 0.050, 0.025, 3.2 to any of: 1.6, 0.80, 0.40, 0.20, 0.10, 0.050, 0.025, 1.6 to any of: 0.80, 0.40, 0.20, 0.10, 0.050, 0.025, 0.80 to any of: 0.40, 0.20, 0.10, 0.050, 0.025, 0.40 to any of: 0.20, 0.10, 0.050, 0.025, 0.20 to any of: 0.10, 0.050, 0.025, 0.10 to any of: 0.050, 0.025, 0.050 to any of: 0.025, etc.Additional Layer Features Certain exemplary embodiments can include layer features that can be created through the use of lithographic etching and/or deposition. These embodiments can include the size, shape, and/or positional orientation of features relative to the X- and/or Y-axes of a layer and/or their relationship to features on neighboring layers along the Z-axis of the assembled laminated mold. These parameters can define certain geometric aspects of the structure. For example, FIG. 10A is a top view of a layer 10010 having a pattern of repeating features (a redundant array of shapes), and FIG. 10B is a top view of a layer 10020 having a variety of differently shaped features (a non-redundant collection of shapes). Although not shown, a layer can have both redundant and non-redundant features. The terms “redundant” and/or “non-redundant” can refer to either positive or negative features. Thus, these parameters also can define the shapes and/or spatial forms of features, the number of features in a given area, secondary structures and/or spaces incorporated on or around a feature, and/or the spaces between features. The control of spacing between features can provide additional functionality and, for instance, allow integration of devices with micro-electronics. For example, conductive micro features could be arrayed (redundantly or non-redundantly) to align accurately with application specific integrated circuits (ASIC) to control features. Also, features could be arrayed for applications where non-linear spacing between features could enhance device functionality. For example, filtration elements could be arrayed in such a way as to match the flow and pressure profile of a fluid passing over or through a filtration media. The spacing of the filtration elements could be arrayed to compensate for the non-linear movement of the fluid. Cavity Definition Using Lithography A cavity formed in accordance with certain exemplary embodiments can assume a shape and/or spatial form that includes one or more predetermined “protruding undercuts”. Imaginably rotating the X-Y plane about its origin to any particular fixed orientation, a cavity is defined as having a “protruding undercut” when a first section of the cavity taken perpendicular to the Z-axis (i.e., parallel to the X-Y plane) has a predetermined dimension in the X- and/or Y-direction greater than the corresponding dimension in the X- and/or Y-direction of a second section of the cavity taken perpendicular to the Z-axis, the second section further along in the direction of eventual demolding of a cast part relative to the mold (assuming the demolding operation involves pulling the cast part free from the mold). That is, the X-dimension of the first section is intentionally greater than the X-dimension of the second section by a predetermined amount, or the Y-dimension of the first section is intentionally greater than the Y-dimension of the second section by a predetermined amount, or both. In still other words, for the purposes of this patent application, the term protruding undercut has a directional component to its definition. FIG. 11 is a top view of an exemplary stacked laminated mold 11000. FIG. 12 is a cross-sectional view of a mold 11000 taken at section lines 12-12 of FIG. 11, and showing the layers 12010-12060 of mold 11000 that cooperatively define a cavity having protruding undercuts 12022 and 12042. Direction A is the relative direction in which a part cast using mold 11000 will be demolded, and/or pulled away, from mold 11000. FIG. 12 also shows that certain layers 12020, 12040 of mold 11000 have been formed by controlled depth etching. As shown in FIG. 12, mold 11000 defines an internal mold surface 12070, which is defined in part by protruding undercuts 12022 and 12042. FIG. 13 is a side view of a cast part 13000 formed using mold 11000. As shown in FIG. 13, cast part 13000 defines an external part periphery or surface 13100, which is defined in part by 3-dimensional micro-features 13400 and 13600 that substantially spatially invertedly replicate protruding undercuts 12022 and 12042. To make layers for certain embodiments of a laminated mold, such as layers 2010 of FIG. 2, a photo-sensitive resist material coating (not shown) can be applied to one or more of the major surfaces (i.e., either of the relatively large planar “top” or “bottom” surfaces) of a micro-machining blank. After the blank has been provided with a photo-resist material coating on its surfaces, “mask tools” or “negatives” or “negative masks”, containing a negative image of the desired pattern of openings and registration features to be etched in the blank, can be applied in alignment with each other and in intimate contact with the surfaces of the blank (photo-resist materials are also available for positive patterns). The mask tools or negatives can be made from glass, which has a relatively low thermal expansion coefficient. Materials other than glass can be used provided that such materials transmit radiation such as ultraviolet light and have a reasonably low coefficient of thermal expansion, or are utilized in a carefully thermally-controlled environment. The mask tools can be configured to provide an opening of any desired shape and further configured to provide substantially any desired pattern of openings. The resulting sandwich of two negative masks aligned in registration and flanking both surfaces of the blank then can be exposed to radiation, typically in the form of ultraviolet light projected on both surfaces through the negative masks, to expose the photo-resist coatings to the radiation. Typically, the photo-resist that is exposed to the ultraviolet light is sensitized while the photo-resist that is not exposed is not sensitized because the light is blocked by each negative masks' features. The negative masks then can be removed and a developer solution can be applied to the surfaces of the blank to develop the exposed (sensitized) photo-resist material. Once the photo-resist is developed, the blanks can be micro-machined using one or more of the techniques described herein. For example, when using photo-chemical-machining, an etching solution can react with and remove the layer material not covered by the photo-resist to form the precision openings in the layer. Once etching or machining is complete, the remaining unsensitized photo-resist can be removed using a chemical stripping solution. Sub-Cavities on Layers Cavities can include sub-cavities, which can be engineered and incorporated into the molding and casting scheme using several methods. FIG. 14 is a top view of a laminated mold 14000. FIG. 15 is a cross-sectional view of mold 14000 taken at section lines 15-15 of FIG. 14, and showing the sub-cavities 15010 within layer 15030 of mold 14000. Note that because layer 15030 is sandwiched between layers 15020 and 15040, sub-cavities 15010 can be considered “sandwiched”, because sub-cavities are at least partially bounded by a ceiling layer (e.g., 15020) and a floor layer (e.g., 15040). Note that, although not shown, a sub-cavity can extend to one or more outer edges of its layer, thereby forming, for example, a sandwiched channel, vent, sprew, etc. FIG. 16 is a perspective view of cast part 16000 formed using mold 14000, and having protrusions 16010 that reflectively (invertedly) replicate sandwiched sub-cavities 15010. Because cast part can very accurately reflect the geometries of sub-cavities, such sub-cavities can be used to produce secondary features that can be incorporated with a desired structure. Examples of secondary features include fluid channels passing through or between features, protrusions such as fixation members (similar to Velcro-type hooks), reservoirs, and/or abrasive surfaces. Moreover, a secondary feature can have a wall which can have predetermined surface finish, as described herein. There are a number of methods for producing sub-cavities in a laminated mold. For example, in the field of photo-chemical-machining, the practice of partially etching features to a specified depth is commonly referred to as “controlled depth etching” or CDE. CDE features can be incorporated around the periphery of an etched feature, such as a through-diameter. Because the CDE feature is partially etched on, for example, the top surface of the layer, it can become a closed cavity when an additional layer is placed on top. Another method could be to fully etch the sub-cavity feature through the thickness of the layer. A cavity then can be created when the etched-through feature is sandwiched between layers without the features, such as is shown in FIG. 15. Combinations of micro-machining techniques can be used to create sub-cavities. For example, photo-chemical-machining (PCM) can be used to create the etched-through feature in the layer, while ion etching could be applied as a secondary process to produce the sub-cavities. By combined etching techniques, the sub-cavities can be etched with much finer detail than that of PCM. Micro-Structures, Features, and Arrays on Non-Planar Surfaces Certain exemplary embodiments can allow the production of complex three-dimensional micro-devices on contoured surfaces through the use of a flexible cavity mold insert. One activity of such a process can be the creation of a planar laminated mold (stack lamination), which can define the surface or 3-dimensional structures. A second mold (derived mold) can be produced from the lamination using a flexible molding material such as silicone RTV. The derived mold can be produced having a thin backing or membrane layer, which can act as a substrate for the 3-dimensional surface or features. The membrane then can be mechanically attached to the contoured surface of a mold insert, which can define the casting's final shape with the incorporated 3-dimensional features or surface. Because a mold can be derived from a series of previous molds, any derived mold can be considered to be descended from each mold in that series. Thus, a given derived mold can have a “parent” mold, and potentially a “grandparent” mold, etc. Likewise, from a stack lamination can descend a first derived, descendant, or child mold, from which a second derived, descendent, or grandchild mold can be descended, and so forth. Thus, as used herein to describe the relationship between molds and castings, the root verbs “derive” and “descend” are considered to be synonymous. As an example, FIG. 17 is a top view of a planar laminated mold 17010 having an array of openings 17020. FIG. 18 is a top view of a flexible casting or mold insert 18010 molded using laminated mold 17010. Flexible mold insert 18010 has an array of appendages 18020 corresponding to the array of openings 17020, and a backing layer 18030 of a controlled predetermined thickness. FIG. 19 is a top view of a mold fixture 19010 having an outer diameter 19020 and an inner diameter 19030. Placed around a cylinder or mandrel 19040 within mold fixture 19010 is flexible mold insert 18010, defining a pour region 19050. Upon filling pour region 19050, a casting is formed that defines a cylindrical tube having a pattern of cavities accessible from its inner diameter and corresponding to and formed by the array of appendages 18020 of flexible mold insert 18010. As another example, FIG. 20 is a top view of a planar laminated mold 20010 having an array of openings 20020. FIG. 21 is a top view of a flexible casting or mold insert 21010 molded using laminated mold 20010. Flexible mold insert 21010 has an array of appendages 21020 corresponding to the array of openings 20020, and a backing layer 21030 of a controlled predetermined thickness. FIG. 22 is a top view of a mold fixture 22010 having an outer diameter 22020 and an inner diameter 22030. Placed around the inside diameter 22030 within mold fixture 22010 is flexible mold insert 21010, defining a pour region 22050. Upon filling pour region 22050, a casting is formed that defines a cylindrical tube having a pattern of cavities accessible from its outer diameter and corresponding to and formed by the array of appendages 21020 of flexible mold insert 21010. Through these and related approaches, the 3-dimensional structure or surface can be built-up at the planar stage, and can be compensated for any distortions caused by forming the membrane to the contoured surface. The fabrication of the laminated mold can use specific or combined micro-machining techniques for producing the layers that define the aspect-ratio and 3-dimensional geometry. Micro-surfaces and/or structures can be transferred to many contours and/or shapes. For example, micro-patterns can be transferred to the inside and/or outside diameter of cylinders or tubes. Specific examples demonstrating the capabilities of this method are provided later in this document. Cavity Inserts The term mold insert is used herein to describe a micro-machined pattern that is used for molding and/or fabrication of a cast micro-device, part, and/or item. The laminated or derived mold described in this document also can be considered a mold insert. Cavity inserts are described here as a subset of a mold insert. Cavity inserts are objects and/or assemblies that can be placed within a cavity section of a mold but that do not take up the entire cavity space, and that provide further features to a 3-dimensional mold. As an example, FIG. 23 is a perspective view of a laminated mold 23010 having an array of cylindrical cavities 23020, each extending from top to bottom of mold 23010. FIG. 24 is a close-up perspective view of a single cylindrical cavity 23020 of mold 23010. Suspended and extending within cavity 23020 are a number of cavity inserts 23030. FIG. 25 is a perspective view of a cast part 25010 having numerous cavities 25020 formed by cavity inserts 23030. A cavity insert can also be produced using certain embodiments. This is further explained later in the section on non-planar molds. An insert can be a portion of a mold in the sense that the insert will be removed from the cast product to leave a space having a predetermined shape within the product. An insert alternatively can become part of a final molded product. For instance, if it is desirable to have a composite end product, then a process can be engineered to leave an insert in place in the final molded product. As an example of a cavity insert, a 3-dimensional mold insert can be produced using one or more embodiments, the insert having an array of cavities that are through-diameters. The cast part derived from this mold can reverse the cavities of the mold as solid diameters having the shape, size and height defined by the mold. To further enhance functionality, cavity inserts can be added to the mold before the final casting is produced. In this case, the cavity insert can be a wire formed in the shape of a spring. The spring can have the physical dimensions required to fit within a cavity opening of the mold, and can be held in position with a secondary fixture scheme. The spring-shaped cavity insert can be removed from the cast part after the final casting process is completed. Thus, the cavity section of the mold can define the solid shape of the casting while the cavity insert can form a channel through the solid body in the shape and width of the insert (the spring). The cavity can serve as, for example, a reservoir and/or a fluid flow restrictor. The examples given above demonstrate the basic principle of a cavity insert. Additional design and fabrication advances can be realized by using this method to create cavity inserts. For example, photo-chemical-machining can be used to create a mold that has larger cavity openings, while reactive-ion-etching can be used to create finer features on a cavity insert. Fabricating the Laminated Mold Certain exemplary embodiments can involve the fabrication of a laminated mold which is used directly and/or as an intermediate mold in one or more subsequent casting and/or molding processes. FIG. 26 is a block diagram illustrating various devices formed during an exemplary method 26000 for fabricating a laminated mold having micro-machined layers that can be patterned and/or etched, and stacked to create a 3-dimensional mold. The laminated mold can be produced as a negative or positive replication of the desired finished casting. For the purpose of creating a laminated mold, any of three elements can be implemented: 1) creating a lithographic mask 26010 defining the features of each unique layer, 2) using lithographic micro-machining techniques and/or micro-machining techniques to produce patterned layers 26020, and/or 3) aligning, stacking, and/or laminating the patterned layers into a stack 26030 in order to achieve the desired 3-dimensional cavity shape, aspect ratios, and/or mold parameters desired for a laminated mold 26040.Lithographic Techniques Using lithography as a basis for layer fabrication, parts and/or features can be designed as diameters, squares, rectangles, hexagons, and/or any other shape and/or combination of shapes. The combinations of any number of shapes can result in non-redundant design arrays (i.e. patterns in which not all shapes, sizes, and/or spacings are identical, as shown in FIG. 10). Lithographic features can represent solid or through aspects of the final part. Such feature designs can be useful for fabricating micro-structures, surfaces, and/or any other structure that can employ a redundant and/or non-redundant design for certain micro-structural aspects. Large area, dense arrays can be produced through the lithographic process, thereby enabling creation of devices with sub-features and/or the repeatable production of multiple devices in a batch format. Note that such repeatable batch production can occur without substantial degradation of the mold. Lithography can also allow the creation of very accurate feature tolerances since those features can be derived from a potentially high-resolution photographic mask. The tolerance accuracy can include line-width resolution and/or positional accuracy of the plotted features over the desired area. In certain embodiments, such tolerance accuracy can enable micro-scale fabrication and/or accurate integration of created micro-mechanical devices with microelectronics. Photographic masks can assist with achieving high accuracy when chemical or ion-etched, or deposition-processed layers are being used to form a laminated mold through stack lamination. Because dimensional changes can occur during the final casting process in a mold, compensation factors can be engineered at the photo-mask stage, which can be transferred into the mold design and fabrication. These compensation factors can help achieve needed accuracy and predictability throughout the molding and casting process. Photographic masks can have a wide range of potential feature sizes and positional accuracies. For example, when using an IGI Maskwrite 800 photoplotter, an active plotting area of 22.8×31.5 inches, minimum feature size of 5 microns, and positional accuracy of +−1 micron within a 15×15 inch area is possible. Using higher resolution lithographic systems for mask generation, such as those employed for electron beam lithography, feature sizes as small as 0.25 microns are achievable, with positional tolerances similar to the Maskwrite plotter, within an area of 6×6 inches. Layer Machining and Material Options Another aspect to fabricating the laminated mold can be the particular technique or techniques used to machine or mill-out the features or patterns from the layer material. In certain embodiments, combining lithographic imaging and micro-machining techniques can improve the design and fabrication of high-aspect-ratio, 3-dimensional structures. Some of the micro machining techniques that can be used to fabricate layers for a laminated mold include photo-etching, laser machining, reactive ion etching, electroplating, vapor deposition, bulk micro-machining, surface micro-machining, and/or conventional machining. In certain exemplary embodiments, a laminated mold need only embody the mechanical features (e.g., size, shape, thickness, etc.) of the final casting. That is, it does not have to embody the specific functional properties (i.e. density, conductivity) that are desired to fulfill the application of the final casting. This means that any suitable techniques or materials can be used to produce the layers of the mold. Thus, there can be a wide variety of material and fabrication options, which can allow for a wide variety of engineered features of a layer, laminated mold, and/or derived mold. For instance, although photo-chemical machining can be limited to metallic foils, by using laser machining or reactive ion etching, the choice of materials can become greatly expanded. With regard to laser machining, Resonetics, Inc. of Nashua, N.H. commercially provides laser machining services and systems. For laser machining, a very wide range of materials can be processed using UV and infra-red laser sources. These materials include ceramics, metals, plastics, polymers, and/or inorganics. Laser micro-machining processes also can extend the limits of chemical machining with regards to feature size and/or accuracy. With little or no restriction on feature geometry, sizes on the order of 2 microns can be achievable using laser machining. When a wide variety of materials are available for making the laminated mold, process-compatibility issues can be resolved when choosing the material from which to create the mold. An example of this would be to match the thermal properties of casting materials with those of the laminated mold, in instances where elevated temperatures are needed in the casting or molding process. Also the de-molding properties of the mold and/or casting material can be relevant to the survival of the mold. This, for example, might lead one to laser-machine the layers from a material such as Teflon, instead of a metal. The laser machining process could be compatible with the Teflon and the Teflon could have greater de-molding capabilities than a metallic stack lamination. In certain exemplary embodiments, only a single laminated stack is needed to produce molds or castings. Also, in certain exemplary embodiments, molds and/or castings can be produced without the need for a clean-room processing environment. For certain exemplary embodiments, the ability to create a single laminated mold and then cast the final parts can allow for using much thinner foils or advanced etching methods for producing the individual layers. Since feature size can be limited by the thickness of each foil, using thinner foils can allow finer features to be etched. Certain exemplary embodiments can combine various micro-machining techniques to create layers that have very specific functional features that can be placed in predetermined locations along the Z-axis of the mold assembly. For example, photo-chemical-machining can be used to provide larger features and high resolution ion-etching for finer features. Various methods, as described above, can be used to produce layers for a laminated mold. The following examples are given to demonstrate dimensional feature resolution, positional accuracy, and/or feature accuracy of the layers. Ion etching: when using a Commonwealth Scientific Millitron 8000 etching system, for example, a uniform etch area of 18 inches by 18 inches is achievable. Feature widths from 0.5 microns and above are attainable, depending on the lithographic masks and imaging techniques used. A feature, for example a 5 micron wide slot, etched to a depth of 10 microns can be etched to a tolerance of +−1.25 microns in width, and +−0.1 microns in depth. The positional tolerance of features would be the same as those produced on the lithographic masks. Photo-chemical-machining: when using an Attotech XL 547 etching system, for example, a uniform etch area of 20 inches by 25 inches is achievable. Etched through-feature widths from 20 microns and above are attainable, with solid features widths of 15 microns and above also being attainable. A feature, for example a 30 micron diameter etched through 25 microns of copper, can be etched to a tolerance of +−2.5 microns or 10% of the foil thickness. The positional tolerance of such features would be the same as those produced on the lithographic masks. Laser micromachining: when using a PIVOTAL laser micromachining system, for example, a uniform machining area of 3 inches by 3 inches is achievable. Machined through-feature sizes from 5 microns and above are attainable. A feature, for example a 5 micron wide slit machined through 25 microns of stainless steel, can be machined to a tolerance of +−1 micron. Positional tolerance of +−3 microns is achievable over the 3 inch by 3 inch area. Electro-forming: depending on the size limitations of the photographic masks used for this process, electro-forming over areas as large as 60 inches by 60 inches is attainable. Electro-formed layers having thickness of 2 microns to 100 microns is achievable. A feature, for example a 5 micron wide slit, 15 microns deep, can be formed to a tolerance of +−1 micron. Positional tolerance of features would be the same as those produced on the lithographic masks. Layer Assembly and Lamination As described above, in certain exemplary embodiments, layers can be designed and produced so that feature shape and placement from layer to layer define the desired geometry along the X-, Y-, and/or Z-axes of a mold. The total number (and thickness) of layers in the assembly can define the overall height and aspect ratio of the feature. A feature can be either the solid shape or the space between given structural components. What follows are several exemplary methods of bonding the layers together to form the laminated mold. One exemplary method used to bond layers together is a metal-to-metal brazing technique. This technique can provide a durable mold that can survive high volume production casting and/or can provide efficient release properties from the castings. Prior to assembly, the layers can have 0.00003 inches of a eutectic braze alloy deposited on the top and bottom surfaces of the layers, using standard electro-plating techniques. An example of a braze material is CuSil™, which is comprised of copper and silver, with the percentage of each being variable for specific applications. CuSil™ can be designed specifically to lower the temperatures needed to flow the alloy during the brazing process. One of the potential concerns during the laminating process is to maintain accurate registration of the assembly layers, and/or control the movement of the layers and the bonding fixture when brought to the elevated temperatures needed to flow the braze material. Several methods can be used to achieve this registration and/or control. The first can involve the practice of having two or more alignment features on the layers. FIG. 27 is a perspective view of a plurality of exemplary layers 27000. As illustrated in FIG. 27, one such alignment feature can be a diameter 27010, and the other alignment feature can be an elongated slot 27020. The slot and the diameter can be positioned on each layer one hundred eighty degrees opposed, for example, and can be parallel in orientation with the grain and/or perpendicular to the plane of the layer material. FIG. 28 is a perspective view of an exemplary laminating fixture 28000, which can be fabricated from graphite, for example, and can have two graphite diameter pins 28010 that can be fixed to the lamination fixture at the same distance apart as the diameter 27010 and slot 27020 on the etched layers 27000. The layers can be placed over the pins 28010 so that each layer is orientated accurately to the layer below, using the slot and diameter to align each layer. Alternatively, two or more diameters can be provided on the layers 27000, each of which corresponds to a pin of laminating fixture 28000. During the brazing process, the layered assembly can be heated in a hydrogen atmosphere to a temperature of 825 degrees Celsius, which can cause the CuSil™ braze to flow. As the temperatures elevate, the layers and the fixture material can expand. The slotted alignment feature 27020 can allow the fixture 28000 material to expand or move at a dissimilar rate than the layers, by the presence of the elongated slot on the layer 27000. The slot 27020 can be greater in length than the diameter of pin 28010 in the fixture. The additional length of the slot can be determined by the different coefficient for expansion between the graphite and the assembly layers. Other methods for maintaining the layer alignment during a heated bonding process can include fabricating the bonding fixture from the same material as the assembly layers, which can thus limit the dissimilar movement of the layers and fixture. The alignment and bonding fixture can also be made so that the alignment pins fit nearly perfectly to alignment features on the layers, but the pins in the fixture are allowed to float while being held perpendicular to the face of the alignment fixture. In order to minimize positional errors when bonding layers (stacking errors), tolerances on certain features can be controlled. Referring to FIG. 27, the positional accuracy of features 27010 and 27020 can be controlled by the photographic masks used to produce the layers (exemplary tolerances for masks are provided in the section titled “Lithographic Techniques”, above). The geometric size and tolerance of features 27010 and 27020 can be governed by the layer thickness and/or micromachining method used to produce them (exemplary tolerances for various micromachining techniques are provided in the section titled “Layer Machining and Material Options”, above). When producing a laminated mold, numerous factors can be an influence on the overall tolerances of the features of the mold and/or the casting. For example, when using a stacking fixture, any of the laminating fixture's surface flatness, the laminating fixture's perpendicularity, and the laminating fixture's parallelism can be an influence. Also, the dimensional tolerance of the alignment feature(s) of a layer and/or the positional tolerance of that feature(s) can be an influence. For example, if an alignment pin, protrusion, or other “male” feature will engage a corresponding hole, indentation, or “female” feature to assist in aligning two or more layers, the dimensional tolerance and/or vocational tolerance of male and/or female feature can be an influence on the overall tolerances. For example, referring to FIG. 28, bonding fixture 28000 can include alignment pins 28010 fitted into the top surface of fixture 28000. In a particular experiment, through the use of a surface grinding process, followed by a planetary lapping and polishing process, the sides and top surface of bonding fixture 28000 were parallel and perpendicular to a tolerance of +−2 microns, with the top surface finish being optically flat to +− one half the wavelength of visible light (400 to 700 nanometers), or about 200 to 350 nanometers. The positional accuracy of the alignment pins and the machined diameters through fixture 28000 was +−5 microns, and the pins were perpendicular to the surface of the fixture to +−2 microns, measured at a pin height of 2 to 5 millimeters. The surface of the described fixture measured 6×6 inches, and was produced using an SIP 5000 Swiss jig boring milling center. Hardened steel alignment pins, having a diameter of 0.092 inches, were precisely ground to a tolerance of +−1.25 microns using a standard grinding operation. The process of laminating the layers can include placing the processed layers over the alignment pins until the desired number of layers have been assembled. The assembled layers and fixture then can be placed in a brazing furnace with uniform weight applied to the top of the fixture. The furnace temperature can be raised to a temperature of 825 degrees Celsius, in a hydrogen atmosphere (a vacuum atmosphere has also been shown to work) for 45 minutes. This temperature can be sufficient to allow the braze material to uniformly flow and connect the layers together at all contact points. The fixture then can be cooled in the hydrogen atmosphere for 2 hours and removed for disassembly. The graphite pins can be removed, freeing the bonded structure from the lamination fixture. The brazed lamination now can be ready for the final process step, which can be to coat the entire assembly with a hard nickel surface. The nickel coating can be applied to the laminated assembly using electro-plating techniques, which can deposits 0.0001 inches of nickel. The nickel-plated surface can act as an interface material that can enhance the release and durability properties of the assembled mold. Another exemplary method that can be used to bond layers can make use of a thermo-cured epoxy rather than metal-to-metal brazing. Prior to assembly, the layers can be coated with an epoxy, MAGNA-TAC® model E645, diluted 22:1 with acetone. The thinned epoxy can be applied to the top and bottom surfaces of the layers using a standard atomizing spray gun. The layers can be spray coated in such a way that the coverage of the epoxy will bond the layers without filling the micro-machined features. A dot coverage of 50% has shown to work. The parameters for dilution and coverage can be provided by the epoxy manufacture, such as the Beacon Chemical Company. The layers then can be assembled to a bonding fixture using, for example, the same technique described in the braze process. The assembled fixture then can be placed in a heated platen press, such as a Carver model #4122. The assembled layers and fixture can be compressed to 40 pounds per square inch and held at a temperature of 350 degrees F. for 3 hours, and allowed to cool to room temperature under constant pressure. The assembly then can be removed from the fixture using, for example, the same technique used for the brazed assembly. In certain embodiments, the technique described in the second example can be considerably less expensive and time consuming than that used for the first. Using the epoxy process, savings can be realized due to the cost of the plating and the additional requirement imposed by the hydrogen braze process compared to epoxy stack laminating. The master derived from the first example can provide more efficient de-molding properties and also can survive a greater number of castings than the epoxy bonded mold. The epoxy-bonded mold can demonstrate a cost effective alternative to brazing and can be used for prototyping or when smaller production quantities are required. Casting and Molding Process Exemplary embodiments can involve the creation of a high-resolution casting mold, having high-aspect-ratio, as well as 3-dimensional features and shapes. A precision stack lamination, comprised of micro-machined layers, can be used as a laminated mold. The laminated mold can be used to produce advanced micro-devices and structures (a.k.a., “micro-electro-mechanical structures” and “MEMS”) and/or can be used to create second (or greater) generation derived molds. The following paragraphs describe the casting process in terms of the materials, fixtures, and/or methods that can be used to produce second-generation molds and final castings. Mold Duplication and Replication For certain exemplary embodiments, the process options for producing molds and cast parts can be numerable. For example, molds can be made as negative 4010 or positive 4020 replications of the desired cast part as shown in FIG. 4. If the mold is made as a positive, a second-generation mold can be created. If the mold is made as a negative, the final part can be cast directly from the mold. For certain exemplary embodiments, the process used to create the layers for the laminated mold can be a determining factor. For example, some production situations can require a second- (or even third) generation derived version of the laminated mold. In certain situations, process parameters can be greatly enhanced by combining molding and casting materials having certain predetermined values for physical properties such as durometer, elasticity, etc. For example, if the cast part is extremely rigid, with poor release properties, a second-generation consumable mold can be used to create the final casting. Further specific examples of this practice, and how they relate to 3-dimensional micro-fabrication are described later in this document. Feature size and positional accuracy for molds and produced parts can be compensated for at the layer production stage of the process. For example, known material properties such as thermal expansion or shrinkage can be accurately accounted for due to, for example, the accuracy levels of the photographic masks and/or laser machining used to produce mold layers. Feature resolution, using various mold making and casting materials, can be accurately replicated for features having a size of 1 micron and greater. Surface finishes have also been reproduced and accurately replicated. For example, layers have been used to form a laminated mold which was used to produce a derived silicone RTV mold. The surface finish of a 0.0015 inch thick stainless steel layer (specified finish as 8-10 micro inches RA max) and a 0.002 inch thick copper layer (specified finish as 8-20 micro inches RA max) were easily identified on the molded surfaces of the derived RTV mold. The surfaces were observed at 400× magnification using a Nikon MM11 measuring scope. The same surface finishes were also easily identified when cast parts were produced from the derived mold using a casting alloy CERROBASE™. Very smooth surface finishes, such as those found on glass, have also been reproduced in molds and castings. Materials for Molds and Castings For certain exemplary embodiments, there can be hundreds, if not thousands of material options for mold making and casting. Described below are some potential considerations regarding the selection of mold and casting materials that can meet the requirements of, for instance, 3-dimensional MEMS. To insure the accuracy and repeatability of certain cast micro-devices, the casting material can have the capability to resolve the fine 3-dimensional feature geometries of the laminated mold. Typical dimensions of MEMS can range from microns to millimeters. Other structures having micro features can have much larger dimensions. For certain embodiments, the mold's cavity geometry can influence the release properties between the mold and the casting, thereby potentially implicating the flexibility (and/or measured durometer) of the materials used. Other material compatibility issues also can be considered when using a casting process. Certain exemplary embodiments of a process have been developed in order to enable the production of 3-dimensional micro-structures from a wide range of materials, tailored to specific applications. The ability to use various materials for molds and castings can greatly expand the product possibilities using this technique. One material that has been successfully used for creating castings from a laminated mold is an elastomeric product, referred to generally as RTV silicone rubber, although other materials could also be successful depending on process or product requirements. A wide range of silicone-based materials designed for various casting applications are commercially available through the Dow Corning Corporation of Midland, Mich. For example, the Silastic® brand products have proven successful, possibly because of their resolution capability, release characteristics, flexibility, durability, and/or the fact that they work in a wide range of process temperatures. Although other types of silicone rubber products could be used, each of the Dow Corning Silastic® brand products that have been used consists of two components; a liquid silicone rubber and a catalyst or curing agent. Of the Dow Corning Silastic® brand products, there are two basic curing types: condensation, and addition cure. The two types can allow for a range of variations in material viscosities and cure times. The three primary products used in the earliest tests are Silastic® J RTV Silicone Rubber, Silastic® M RTV Silicone Rubber, and Silastic® S RTV Silicone Rubber. Product specifications are provided in several of the examples at the end of this document. The Dow Corning Silastic® products used thus far have similar specifications regarding shrinkage, which increases from nil up to 0.3 percent if the silicone casting is vulcanized. Vulcanization can be accomplished by heating the silicone to a specific elevated temperature (above the casting temperature) for a period of 2 hours. Vulcanizing can be particularly useful when the casting is to be used as a regenerated mold, and will be subjected to multiple castings. In addition to RTV silicone rubber, urethanes and other materials also have properties that can be desirable for laminated molds, derived molds, and/or castings, depending on the specific requirement. For example, when producing certain 3-dimensional micro-structures with extreme aspect ratios, very fine features, or extreme under-cuts, de-molding can be difficult. In certain situations, the rigidity of the mold also can be relevant, especially in certain cases where mold features have high-aspect ratios. For example, the practice of sacrificing or dissolving laminated second or third generation molds can be used when castings require very rigid molds, and/or where the de-molding of castings becomes impossible. There are several families of materials that can be used for producing laminated molds, derived molds, and/or final cast devices including, for example: Acrylics: such as, for example, PMMA acrylic powder, resins, and/or composites, as well as methacrylates such as butyl, lauryl, stearyl, isobutyl, hydroxethyl, hydroxpropyl, glycidyl and/or ethyl, etc. Plastic polymerics: such as, for example, ABS, acetyl, acrylic, alkyd, flourothermoplastic, liquid crystal polymer, styrene acrylonitrile, polybutylene terephthalate, thermoplastic elastomer, polyketone, polypropylene, polyethylene, polystyrene, PVC, polyester, polyurethane, thermoplastic rubber, and/or polyamide, etc. Thermo-set plastics: such as, for example, phenolic, vinyl ester, urea, and/or amelamine, etc. Rubber: such as, for example, elastomer, natural rubber, nitrile rubber, silicone rubber, acrylic rubber, neoprene, butyl rubber, fluorosilicone, TFE, SBR, and/or styrene butadiene, etc. Ceramics: such as, for example, silicon carbide, alumina, silicon carbide, zirconium oxide, and/or fused silica, calcium sulfate, luminescent optical ceramics, bio-ceramics, and/or plaster, etc. Alloys: such as, for example, aluminum, copper, bronze, brass, cadmium, chromium, gold, iron, lead, palladium, silver, sterling, stainless, zinc platinum, titanium, magnesium, anatomy, bismuth, nickel, and/or tin, etc. Wax: such as, for example, injection wax, and/or plastic injection wax, etc. There can be many material options within these groups that can be utilized when employing certain embodiments. For example, in certain embodiments, metals and metal alloys can be primarily used as structural materials of final devices, but also can add to function. Exemplary functional properties of metals and/or alloys can include conductivity, magnetism, and/or shape memory. Polymers also can be used as structural and/or functional materials for micro-devices. Exemplary functional properties can include elasticity, optical, bio-compatibility, and/or chemical resistivity, to name a few. Materials having dual (or more) functionality, often referred to as engineered “smart” materials, could be incorporated into a final molded product or a mold. Additional functionality could utilize electrostatic, mechanical, thermal, fluidic, acoustic, magnetic, dynamic, and/or piezo-electric properties. Ceramics materials also can be used for applications where specialty requirements may be needed, such as certain high-temperature environments. Depending on the material that is chosen, there can be many alternative methods to solidify the casting material. The term “solidify” includes, but is not limited to, methods such as curing, vulcanizing, heat-treating, and/or chemically treating, etc. Mold Fixtures, Planar and Contoured For certain exemplary embodiments, there can be a wide range of engineering options available when designing a casting mold. The casting process and geometry of the final product can determine certain details and features of the mold. Options can be available for filling and/or venting a mold, and/or for releasing the casting from the mold. Two basic approaches have been used for demonstrating the certain exemplary methods for mold design and fabrication. These approaches can be categorized as using a single-piece open-face mold or a two-part closed mold. In certain exemplary embodiments, each of the mold types can include inserting, aligning, and assembling the laminated mold (or duplicate copy) in a fixture. The fixture can serve several purposes, including bounding and/or defining the area in which to pour the casting material, capturing the casting material during the curing process, allowing the escape of air and/or off-gases while the casting material is degassed, and/or enabling mechanical integration with the casting apparatus. The fixture can be configured in such a way that all sides surrounding the mold insert are equal and common, in order to, for example, equalize and limit the effects of thermal or mechanical stresses put on the mold during the casting process. The mold fixture also can accommodate the de-molding of the casting. Certain exemplary embodiments of this method can provide the ability to mold 3-dimensional structures and surfaces on contoured surfaces. The basic technique is described earlier in this document in the design parameter section. One element of the technique can be a flexible mold insert that can be fixed to a contoured surface as shown in FIGS. 19 and 22. The mold insert can be made with a membrane or backing thickness that can allow for integration with various fixture schemes that can define the contoured shape. For non-planar molds, the contour of the mold fixture can be produced by standard machining methods such as milling, grinding, and/or CNC machining, etc. The flexible mold insert can be attached to the surface of the mold using any of several methods. One such method is to epoxy bond the flexible insert to the fixture using an epoxy that can be applied with a uniform thickness, which can be thin enough to accommodate the mold design. Other parameters that can be considered when choosing the material to fix a membrane to a fixture include durability, material compatibility, and/or temperature compatibility, etc. A detailed description of a non-planar mold is given as an example further on. Casting and Molding Processes Various techniques can be used for injecting or filling cavity molds with casting materials, including injection molding, centrifugal casting, and/or vibration filling. An objective in any of these techniques can be to fill the cavity with the casting material in such a way that all of the air is forced out of the mold before the cast material has solidified. The method used for filling the cavity mold can depend on the geometry of the casting, the casting material, and/or the release properties of the mold and/or the cast part. As has been described earlier, an open face mold, using flexible RTV rubber has been found to work effectively. In certain embodiments, an open face mold can eliminate the need for having carefully designed entrance sprue and venting ports. The open face mold can be configured to create an intermediate structure that can have a controlled backing thickness which can serve any of several purposes: 1) it can be an open cavity section in the casting mold which can serve as an entrance point in which to fill the mold; 2) it can serve as a degassing port for the air evacuation during the vacuum casting process; 3) it can create a backing to which the cast part or parts can be attached and/or which can be grasped to assist in de-molding the casting from the flexible mold. In casting processes in which the casting material is heated, the mold temperature and the cooling of the casting can be carefully controlled. For example, when casting a lead casting alloy such as CERROBASE, the alloy can be held at a temperature of 285 degrees F., while the mold material can be preheated 25-30 degrees higher (310-315 degrees F.). The molten alloy can be poured and held at or above the melting point until it is placed in the vacuum environment. The mold then can be placed in a vacuum bell jar, and held in an atmosphere of 28 inches of mercury for 3-4 minutes. This can remove any air pockets from the molten metal before the alloy begins to solidify. As soon as the air has been evacuated, the mold can be immediately quenched or submersed in cold water to rapidly cool the molten metal. This can help minimize shrinkage of the cast metal. In certain exemplary embodiments, no vent holes or slots are provided in the mold, and instead, air can be evacuated from the mold prior to injection. In certain exemplary embodiments, temperature variation and its effect on the micro-structure can be addressed via enhanced heating and cooling controls in or around the mold. In certain exemplary embodiments, heat can be eliminated from the curing process by replacing the molding materials with photo-curing materials. Some of the methods that can be used for micro-molding and casting include micro-injection molding, powder injection molding, metal injection molding, photo molding, hot embossing, micro-transfer molding, jet molding, pressure casting, vacuum casting, and/or spin casting, etc. Any of these methods can make use of a laminated or derived mold produced using this method. De-Molding and Finish Machining A controlled backing thickness can be incorporated into the casting to create an intermediate structure. One purpose of the intermediate can be to create a rigid substrate or backing, that allows the casting to be grasped for removal from the mold without distorting the casting. The thickness of the backing can be inversely related to the geometry of the pattern or features being cast. For example, fine grid patterns can require a thicker backing while coarse patterns can have a thinner backing. The backing can be designed to have a shape and thickness that can be used to efficiently grasp and/or pull the cast part from the mold. Following de-molding, the intermediate can be machined to remove the backing from the casting. Because the thickness of the backing can be closely controlled, the backing can be removed from the cast structure by using various precision machining processes. These processes can include wire and electrode EDM (electrode discharge machining), surface grinding, lapping, and/or fly cutting etc. In instances where extremely fine, fragile patterns have been cast, a dissolvable filler or potting material can be poured and cured in the cast structure prior to the removal of the backing from the grid. The filler can be used to stabilize the casting features and eliminate possible damage caused by the machining process. The filler can be removed after machining-off the backing. A machinable wax has been found to be effective for filling, machining, and dissolving from the casting. In some part designs, de-molding the casting from the mold might not be possible, due to extreme draft angles or extremely fine features. In these cases, the mold can remain intact with the cast part or can be sacrificed by dissolving the mold from casting. A wide range of three-dimensional micro-devices can be fabricated through the use of one or more embodiments of various fabrication processes, as demonstrated in some of the following examples. This example demonstrates fabrication of an array of complex 3-dimensional cavity features having high aspect ratio. This example makes use of a second-generation derived mold for producing the final part, which is an array of sub-millimeter feedhorns. A feedhorn is a type of antenna that can be used to transmit or receive electromagnetic signals in the microwave and millimeter-wave portion of the spectrum. At higher frequencies (shorter wavelengths) the dimensions can become very small (millimeters and sub-millimeter) and fabrication can become difficult. Using certain exemplary embodiments, a single horn, an array of hundreds or thousands of identical horns, and/or an array of hundreds or thousands of different horns can be fabricated. FIG. 29 is a top view of stack lamination mold 29000 that defines an array of cavities 29010 for fabricating feedhorns. FIG. 30 is a cross-section of a cavity 29010 taken along section lines 30-30 of FIG. 29. As shown, cavity 29010 is corrugated, having alternating cavity slots 30010 separated by mold ridges 30020 of decreasing dimensions, that can be held to close tolerances. In an exemplary embodiment, an array of feedhorns contains one thousand twenty identical corrugated feedhorns, each designed to operate at 500 GHz, and the overall dimensions of the feed horn array are 98 millimeters wide by 91 millimeters high by 7.6 millimeters deep. The fabrication of this exemplary array can begin with the creation of a laminated mold, comprised of micro-machined layers, and assembled into a precision stack lamination. Step 1: Creating the laminated mold: The laminated mold in this example was made of 100 layers of 0.003″ thick beryllium copper (BeCu) sheets that were chemically etched and then laminated together using an epoxy bonding process. Infinite Graphics, Inc. of Minneapolis, Minn. was contracted to produce the photo-masks needed for etching the layers. The masks were configured with one thousand twenty diameters having a center-to-center spacing of 2.5 millimeters. An IGI Lazerwrite photo plotter was used to create the masks, which were plotted on silver halite emulsion film. The plotter resolution accuracy was certified to 0.5 micrometers and pattern positional accuracy of plus or minus 0.40 micrometers per lineal inch. The layers were designed so that horn diameters were different from layer to layer, so that when the layers were assembled, the layers achieved the desired cross-section taper, slot, and ridge features shown in simplified form in FIG. 30. A total of 100 layers were used to create a stacked assembly 7.6 millimeters thick. The layers were processed by Tech Etch, Inc. of Plymouth, Mass., using standard photo-etching techniques and were etched in such a way that the cross-sectional shape of the etched walls for each layer are perpendicular to the top and bottom surfaces of the layer (commonly referred to as straight sidewalls). In this example, the method chosen to bond the etched layers together used a thermo-cured epoxy (MAGNA-TAC model E645), using the process and fixturing described earlier in the section on layer assembly and lamination. The assembled fixture was then placed in a 12 inch×12 inch heated platen press, Carver model No. 4122. The fixture was compressed to 40 pounds per square inch and held at a temperature of 350 degrees F. for 3 hours, then allowed to cool to room temperature under constant pressure. The assembly was then removed from the fixture and the alignment pins removed, leaving the bonded stack lamination. The laminated mold (stack lamination) was then used to produce the final casting mold. Step 2: Creating the casting mold: The second step of the process was the assembly of the final casting mold, which used the precision stack lamination made during step 1 as a laminated mold. The casting mold created was a negative version of the lamination, as shown in perspective view for a single feed horn 31000 in FIG. 31. Also shown is a feedhorn ridge 31010 that can correspond to a cavity slot 30010, and a feedhorn base 31020. For this example, Silastic® J RTV Silicone Rubber was used to make the final casting mold. This product was chosen because it is flexible enough to allow easy release from the laminated mold without damaging the undercut slots and rings inside the feedhorns, and because of its high-resolution capability. Described below are the product specifications. Silastic® J: Durometer Hardness:56 Shore A pointsTensile Strength, psi:900Linear Coefficient of Thermal Expansion:6.2 × 10-4Cure Time at 25 C.:24 hours The Silastic® J Silicone RTV was prepared in accordance with the manufacturer's recommendations. This included mixing the silicone and the curing agent and evacuating air (degassing) from the material prior to filling the mold-making fixture. At the time the example was prepared, the most effective way of degassing the Silicone prior to filling the mold fixture was to mix the two parts of the Silicone and place them in a bell jar and evacuate the air using a dual stage vacuum pump. The material was pumped down to an atmosphere of 28 inches of mercury and held for 5 minutes beyond the break point of the material. The Silicone was then ready to pour into the mold fixture. As shown in the side view of FIG. 32, an open-face fixture 32000 was prepared, the fixture having a precision-machined aluminum ring 32010, precision ground glass plate 32030, rubber gaskets 32040, 32050 and the laminated mold 32060. The base 32020 of the fixture was thick Plexiglas. On top of the Plexiglas base was a glass substrate 32030. Rubber gasket 32040 separated the glass base and the glass substrate. An additional rubber gasket 32050 was placed on the top surface of the glass substrate 32030 and the laminated mold 32060 was placed on the top gasket. The rubber gaskets were used to prevent unwanted flashing of material during casting. A precision-machined aluminum ring 32010 was placed over the laminated mold subassembly and interfaced with the lower rubber gasket 32040. Generally, the height of the ring and dimensions of the above pieces can depend upon the dimensions of the specific structure to be cast. The ring portion 32010 of the fixture assembly served several purposes, including bounding and defining the area in which to pour mold material, capturing the material during the curing process, and providing an air escape while the mold material was degassed using vacuum. The fixture was configured in a way that all sides surrounding the laminated mold 32060 were equal and common, in order to equalize and limit the effects of thermal or mechanical stresses put on the lamination from the mold material. An open-face mold was used for this example. The mold insert and molding fixture were assembled and filled with the silicone RTV, then the air was evacuated again using a bell jar and vacuum pump in an atmosphere of 28 inches of mercury. After allowing sufficient time for the air to be removed from the silicone, the mold was then heat-cured by placing it in a furnace heated to and held at a constant temperature of 70 degrees F. for 16 hours prior to separating the laminated mold from the derived RTV mold. The molding fixture was then prepared for disassembly, taking care to remove the laminated mold from the RTV mold without damaging the lamination, since the lamination can be used multiple times to create additional RTV molds. The resulting RTV mold was a negative version of the entire feedhorn array consisting of an array of one thousand twenty negative feedhorns, similar to the simplified single horn 31010 shown in perspective view in FIG. 31. Step 3: Casting the feedhorn array: In this example, the cast feedhorn arrays were made of a silver loaded epoxy, which is electrically conductive. In certain exemplary embodiments, binders and/or metallic (or other) powders can be combined and/or engineered to satisfy specific application and/or process specifications. The conductive epoxy chosen for this example provided the electrical conductivity needed to integrate the feedhorn array with an electronic infrared detector array. The conductive epoxy was purchased from the company BONDLINE™ of San Jose, Calif., which designs and manufactures engineered epoxies using powdered metals. Certain of its composite metal epoxies can be cured at room temperature, have high shear strength, low coefficient of thermal expansion, and viscosities suited for high-resolution casting. Exemplary embodiments can utilize various techniques for injecting or filling cavity molds with casting materials. In this example, a pressure casting method was used. The BONDLINE™ epoxy was supplied fully mixed and loaded with the silver metallic powder, in a semi-frozen state. The loaded epoxy was first normalized to room temperature and then pre-heated per the manufacturer's specification. In the pre-heated state the epoxy was uncured and ready to be cast. The uncured epoxy was then poured into the open-face mold to fill the entire mold cavity. The mold was then placed in a pressurized vessel with an applied pressure of 50 psi using dry nitrogen, and held for one hour, which provided sufficient time for the epoxy to cure. The mold was then removed from the pressure vessel and placed in an oven for 6 hours at 225 degrees F., which fully cured the conductive epoxy. Step 4. Demolding and finish machining: After the cast epoxy had been cured, it was ready for disassembly and demolding from the casting fixture and mold. The mold material (RTV silicone) was chosen to be flexible enough to allow the cast feedhorn array to be removed from the casting mold without damaging the undercuts formed by the slots and ridges. When done carefully, the mold could be reused several times to make additional feedhorn arrays. The backing thickness 31020 of the RTV mold shown in FIG. 31 came into play during the de-molding process. The backing was cast thick enough to allow easy grasping to assist with separating the casting mold from the cast piece. In this example, the RTV casting mold was flexible and allowed easy separation without damaging the undercut slots and rings inside the cast feedhorns. Depending on the piece being cast, machining, coating, and/or other finish work can be desirable after de-molding. In this example, a final grinding operation was used on the top surface (pour side of the mold) of the feedhorn array because an open face mold was used. This final grinding operation could have been eliminated by using a closed, two-part mold. This example makes use of certain exemplary embodiments to demonstrate the production of sub-millimeter feedhorns in a batch process. The example uses the same part design and fabrication process described in example 1, with several modifications detailed below. Process Modifications: The process detailed in example 1 was used to produce an array of one thousand twenty feedhorns. The first modification to the process was the casting material used to produce the array. The casting material for this example was a two-part casting polymer sold through the Synair Corporation of Chattanooga, Tenn. Product model “Mark 15 Por-A-Kast” was used to cast the feedhorn array and was mixed and prepared per the manufacturer's specifications. The polymer was also cast using the pressure filling method described in example 1. The next modification was a surface treatment applied to the cast polymer array. A conductive gold surface was deposited onto the polymer array in order to integrate the feedhorns with the detector electronics. The gold surface was applied in two stages. The first stage was the application of 0.5 microns of conduction gold, which was sputter-coated using standard vacuum deposition techniques. The first gold surface was used for a conductive surface to allow a second stage electro-deposition or plating of gold to be applied. The second gold plating was applied with a thickness of 2 microns using pure conductive gold. The final modification was to dice or cut the feedhorns from the cast and plated array into individual feedhorns, that were then suitable for detector integration. A standard dicing saw, used for wafer cutting, was used to cut the feedhorns from the cast array. Process steps 1 and 2 described in example 1 were used to produce a large area array of micro-structures, which are described as negatives of the feedhorn cavities, shown as a single feedhorn in FIG. 31. The laminated mold and molding fixture was used to cast the micro-structures using Dow Corning's Silastic® M RTV Silicone Rubber. This product was chosen because it is flexible enough to release from the mold insert, without damaging the circular steps in the structure, but has the hardness needed to maintain the microstructures in a standing position after being released from the mold. Described below are the product specifications. Silastic® M Durometer Hardness:59 Shore A pointsTensile Strength, psi:650Linear Coefficient of Thermal Expansion:6.2 × 10-4Cure Time at 25 C.:16 hours The Silicone RTV was prepared in accordance with the manufacturer's recommendations, using the process described earlier in example 1, step 2. The laminated mold and molding fixture were assembled and filled with the silicone RTV, using the process described earlier in example 1, step 2. The molding fixture was then prepared for disassembly, taking care to separate the mold insert from the cast silicone array. The resulting casting was an array consisting of one thousand twenty 3-dimensional micro-structures. The shape and dimension of a single structure is shown in simplified form in FIG. 31. Certain exemplary embodiments have been used to produce a 2.5 centimeter length of clear urethane tubing, having 3-dimensional micro-fluid channels on the inside diameter of the tubing. The fluidic tubing was produced using a flexible cavity insert with a controlled backing thickness. The following example demonstrates how the cavity insert can enable the production of three-dimensional features on the inside and outside diameters of cylindrical tubing. Step 1: Creating the mold insert: The first step in the process was to fabricate the micro-machined layers used to produce the cavity insert. The cast tubing was 2.5 centimeters long, having a 3.0 millimeter outside diameter and a 2.0 millimeter inside diameter, with 50 three-dimensional micro-fluidic channels, equally spaced around the interior diameter of the tube. FIG. 33 shows a side view of the tubing 33000, the wall of which defines numerous fluidic channels 33010. Although each fluidic channel could have different dimensions, in this example each channel was 0.075 mm in diameter at the entrance of the channel from the tube, and each channel extended 0.075 mm deep. Each channel tapered to a diameter of 0.050 mm, the taper beginning 0.025 mm from the bottom of each channel. Photo-chemical machining was used to fabricate the layers for the laminated mold. FIG. 34 is a top view of a such a laminated mold 34000, which was created using several photo masks, one of which with a similar top view. Mold 34000 includes an array of fluidic channels 34010 In this particular experiment, the length of channels 34010 was approximately 25 millimeters, and the width of each collection of channels was approximately 6.6 millimeters. FIG. 35 is a cross-section of mold 34000 taken at section lines 35-35 of FIG. 34. To the cross-sectional shape of channel 34010, a first copper foil 35010 having a thickness of 0.025 mm, and a second copper foil 35020 having a thickness of 0.050 mm, were chemically etched and then laminated together using a metal-to-metal brazing process. Each of the layers used in the laminated mold assembly used a separate photo-mask. The masks used for layer 35020 were configured with a 9.50×0.075 mm rectangular open slot, arrayed redundantly in 50 places, a portion of which are illustrated in FIG. 34. To achieve the desired taper, two masks were used for layer 35010. The bottom mask was configured with a 9.50×0.075 mm rectangular open slot and the top mask was configured with a 9.50×0.050 rectangular open slot, each of the slots were also redundantly arrayed in 50 places. The photo-masks were produced to the same specifications, by the same vendor as those described in example 1, step 1. The layers were designed so that the slot placement was identical from layer to layer, which when assembled, produced the cross-sectional shape for the channels as shown in FIG. 35. The final thickness of the lamination was specified at 0.083 millimeters, which required one 0.025 layer of copper foil, and one 0.050 thick layer of copper foil, leaving a total thickness amount of 0.002 millimeters for braze material on each side of each etched layer. The layers were photo-etched by the same vendor, and same sidewall condition as those described in example 1, step 1. The method chosen to bond the grid layers together was a metal-to-metal brazing technique described earlier, in detail as one of two exemplary methods of bonding layers together (eutectic braze alloy) Step 2: Creating the flexible cavity insert: The next step of the process was to create a flexible cavity insert from the brazed layered assembly. FIG. 36 is a side view of cavity insert 36000, which was produced from the brazed assembly with a backing 36010 having a thickness of 0.050 millimeters. The cavity insert 36000 was produced using Silastic® S RTV Silicone Rubber as the base material. The RTV Silicone Rubber was used because of its resolution capability, release properties, dimensional repeatability, and its flexibility to form the insert to a round pin that would be assembled to the final molding fixture. The material properties of Silastic® S are shown below. Silastic® S Durometer Hardness:26 Shore A pointsTensile Strength, psi:1000Linear Coefficient of Thermal Expansion:6.2 × 10-4Cure Time at 25 C.:24 hours The casting fixture used to create the RTV cavity insert was similar to that shown in FIG. 32 and is described in detail in the prior examples. A modification was made to the fixture assembly, which was a top that was placed over the pour area of the mold fixture. This top was placed and located to close the mold after air evacuation and reduce the backing thickness 36010 of the RTV insert to a thickness of 0.050 millimeters, shown in FIG. 36. The Silastic® S RTV Silicone Rubber used for the cavity insert fabrication was prepared in accordance with the manufacturers recommendations, using the process described earlier in example 1, step 2. Step 3: Assembling the molding fixture: The final molding fixture was then ready to be assembled. The molding fixture included a base plate (FIG. 37), the cavity inserts (FIG. 38), and a top plate (FIG. 40). FIG. 37 is a top view of the base plate 37000, which was made from a 0.25 inch aluminum plate that was ground flat and machined using standard CNC machining techniques. The base had six machined diameters 37010 through the plate. These six diameters would accept the cavity insert pins described later. The plate also had machined diameters through the plate, which would accept dowel pins 37020 that were used to align and assemble the top plate and the base plate, as well as 4 bolt diameters 37030 to hold the top and bottom plates together. FIG. 38 is a side view of an insert fixture 38000, that includes the flexible cavity insert 36000 attached to a 3 centimeter long, 1.900 millimeter diameter steel pin 38010. The pin 38010 was ground to the desired dimensions using standard machine grinding techniques. The RTV cavity insert 36000 was cut to the proper size before being attached to the pin. The RTV insert 36000 was attached to outside diameter of the pin 38010 using a controlled layer of two-part epoxy. FIG. 39 is a side view of several insert fixtures 39000 that have been attached to a base plate 37000. Each insert 36000 was attached its corresponding pin 38010 so that the end of pin 38010 could be assembled to a corresponding machined diameter 37010 of base plate 37000 without interference from insert 36000. Once each insert 36000 was attached around the diameter of its corresponding pin 38010 and the pin placed in the corresponding through-diameter of base plate 37010, the pin was held perpendicular to base plate 37000 and in alignment with a top plate of the fixture. FIG. 40 is a top view of a top plate 40000 of the fixture, which was also fabricated of aluminum and machined using CNC techniques. There were six 3.0 millimeter diameters 40010 milled through the thickness of plate 40000, which was 3.0 centimeters thick. Diameters 40010 defined the cavity areas of the mold that would be filled during the final casting process, and aligned to the pins assembled to the base plate. Also incorporated into the top plate were bolt features 40020 and dowel features 40030 needed to align and assemble the top plate 40000 to the base plate 37000. The thickness of top plate 40000 was specified to slightly exceed the desired length of the final cast tubing, which was cut to its final length after casting. The casting fixture was then assembled, first by assembling the cavity insert 38000 to the base plate 37000, followed by assembling the top plate 40000 to the base using bolts and dowels. The top view of a representative cavity section for an assembled fixture is shown in FIG. 19. Step 4: Casting the fluidic tubes: Several fluidic tubes were produced using the assembled casting fixture. A clear urethane was used for the final casting because of its high-resolution, low shrink factor, and transparent properties, which allowed for final inspection of the interior diameter features through the clear wall of the tube. The casting material was purchased from the Alumilite Corporation of Kalamazoo, Mich., under the product name Water Clear urethane casting system. The manufacturer described the cured properties as follows: Hardness, Shore D:82Density (gm/cc)1.04Shrinkage (in/in/) maximum0.005Cure Time (150 degrees F.) 16 hr The urethane was prepared in accordance with the manufacturer's recommendations. This included the mixing and evacuation of air (degassing) from the material prior to filling the mold. The most effective way found for degassing the urethane prior to filling the mold fixture was to mix parts A and B, place them in a bell jar, and evacuate the air using a dual stage vacuum pump. The mixture was pumped down to an atmosphere of 28 inches of mercury and held for 15 minutes beyond the break point of the material The urethane was then ready to pour into the mold fixture. The assembled mold fixture was heated to 125 degrees F. prior to filling the cavities with the urethane. The pre-heating of the mold helped the urethane to flow and fill the cavities of the mold, and aided in the degassing process. The cavity sections of the mold were then filled with the urethane, and the air was evacuated again using a bell jar and vacuum pump in an atmosphere of 28 inches of mercury. After allowing sufficient time for the air to be removed from the urethane, the mold was then removed from the vacuum bell jar and placed in an oven. The mold was heated and held at a constant temperature of 150-180 degrees F. for 16 hours prior to separating the cast tubes from the mold. The molding fixture was then disassembled and the cast tubes were separated from the cavity inserts. The inserts were first removed from the base plate of the fixture. The tubes were easily separated from the cavity insert assembly due to the flexibility and release properties of the silicone RTV, combined with the hardness of the urethane tubes. Example # 4 described the method used for producing cast urethane tubing with micro-fluidic features on the inside diameter of the tube. The current example demonstrates how that process can be altered to produce tubing with the micro-fluidic channels on the outside diameter of the tubing. This example uses a similar part design and the fabrication process described in example 4, with several modifications detailed below. One process modification involved step 3, assembling the molding fixture. For this step, a modification was made to the fixture design that enabled the molded features to be similar to that shown in FIGS. 20-22. The first modification was in the size of the machined diameters in the base plate and the top plate of the fixture described in example 4. The flexible RTV cavity insert that was attached to a pin in example 4 was instead attached to the inside diameters of the top fixture plate, similar to that shown in FIG. 22. In order to accommodate the existing RTV cavity insert, the cavity diameters of the top plate were milled to a size of 1.900 millimeters. The RTV cavity insert was then attached to the milled diameter of the top plate using the same epoxy technique described in example 4. The base plate of the fixture was also modified to accept a 1.0 millimeter diameter pin, and was assembled similar to the that shown in FIG. 22. The same casting process was used as described in example 4. After following the final casting process, with the altered molding fixture, the urethane tubes were produced having the same fluidic channels located on the outside diameter of the cast tube. Certain exemplary embodiments can provide methods for fabricating grid structures having high-resolution and high-aspect ratio, which can be used for radiation collimators, scatter reduction grids, and/or detector array grids. Such devices can be used in the field of radiography to, for example, enhance image contrast and quality by filtering out and absorbing scattered radiation (sometimes referred to as “off-axis” radiation and/or “secondary” radiation). Certain embodiments of such devices can be used in nearly every type of imaging, including astronomy, land imaging, medical imaging, magnetic resonance imaging, tomography, fluoroscopy, non-destructive inspection, non-destructive testing, optical scanning (e.g., scanning, digital copying, optical printing, optical plate-making, faxing, and so forth), photography, ultra-violet imaging, etc. Thus, certain embodiments of such devices can be comprised in telescopes, satellites, imaging machines, inspection machines, testing machines, scanners, copiers, printers, facsimile machines, cameras, etc. Moreover, these machines can process images using analog and/or digital techniques. For the purposes of this description, the term “collimator” is used generally to describe what may also be referred to as a radiation collimator, x-ray grid, scatter reduction grid, detector array grid, or any other grid used in an imaging apparatus and/or process. Certain collimators fabricated according to one or more exemplary embodiments can be placed between the object and the image receptor to absorb and reduce the effects of scattered x-rays. Moreover, in certain exemplary embodiments, such collimators can be used in a stationary fashion, like those used in SPECT (Single Photon Emission Computed Tomography) imaging, or can be moved in a reciprocating or oscillating motion during the exposure cycle to obscure the grid lines from the image, as is usually done in x-ray imaging systems. Grids that are moved are known as Potter-Bucky grids. X-ray grid configurations can be specified by grid ratio, which can be defined as the ratio of the height of the grid to the distance between the septa. The density, grid ratio, cell configuration, and/or thickness of the structure can have a direct impact on the grid's ability to absorb off-axis radiation and/or on the energy level of the x-rays that the grid can block. Certain exemplary embodiments can allow for the use of various materials, including high-density grid materials. Also, certain exemplary can make use of a production mold, which can be derived from a laminated mold. Numerous additional aspects can be fabricated according to certain exemplary embodiments. For example, the laminated mold can be produced from a stack lamination or other method, as discussed above. Moreover, X-ray absorbent material, such as lead, lead alloys, dense metallic composites, and/or epoxies loaded with dense metallic powders can be cast into a mold to produce x-ray absorbing grids. High-temperature ceramic materials also can be cast using a production mold. In addition, the open cells of the ceramic grid structure can be filled with detector materials that can be accurately registered to a collimator. The molds and grids can be fabricated having high-resolution grid geometries that can be made in parallel or focused configurations. The mold can remain assembled to the cast grid to provide structural integrity for grids with very fine septal walls, or can be removed using several methods, and produce an air-cell grid structure. FIG. 41 is a block diagram illustrating an exemplary embodiment of a method 41000 Method 41000 can include the following activities: 1) creating a lithographic mask 41010 defining the features of each unique layer, 2) using lithographic micro-machining techniques and/or micro-machining techniques to produce patterned layers 41020, and 3) aligning, stacking, and/or laminating the patterned layers 41030 in order to achieve the desired 3-dimensional cavity shape, high-aspect ratios, and/or other device features desired for the laminated mold 41040, 4) fabricating a casting mold 41050 derived from the laminated mold, and/or 5) casting x-ray grids (or other parts) 41060 using the derived casting mold. The following discussion describes in detail exemplary activities involved in fabricating certain exemplary embodiments of a laminated mold, fabricating a derived mold from the laminated mold, and finally casting a collimator from the derived mold. Certain variations in the overall process, its activities, and the resulting collimator are noted throughout. In certain exemplary embodiments, the final collimator can be customized as a result of the casting process. For instance, conventional collimators have two separated flat major sides that are parallel to each other, thereby forming a flat, generally planar grid structure. Although certain exemplary embodiments includes methods for forming these collimators, exemplary embodiments of the invention also can be used to form non-planar collimators. An exemplary embodiment of a method can begin with the acquisition, purchase, and/or fabrication of a first collimator. This first collimator can serve as the master collimator from which one or more molds can be formed. The master collimator can be made by any means, including stack lamination, but there is no limitation with respect to how the first or master collimator can be made. Also, as will be explained in more detail, because the master collimator is not necessarily going to be a collimator used in radiography, it is possible to customize this master collimator to facilitate mold formation. The mold itself can be fabricated of many materials. When formed of a flexible material, for example, it is possible to use the mold to make a non-planar collimator. The material of the mold can be customized according to cost and performance requirements. In some embodiments, it is possible to make a mold of material that is substantially transparent to radiation transmission. The mold could be left embedded in the final cast collimator. This particular variation can be applicable when the final collimator has very narrow septal walls and the mold is needed to provide support and definition for the collimator. The mold generally also can be reused to form multiple final (or second) collimators to achieve economies of manufacturing scale. Radiation Opaque Casting Materials for Collimators and Grids A broad selection of base materials can be used for the fabrication of parts, such as x-ray collimators and scatter reduction grids. One potential characteristic of a grid material is sufficient absorption capacity so that it can block selective x-rays or gamma photons from reaching an image detector. In certain embodiments, this characteristic can require high density and/or high atomic number (high z) materials. Certain exemplary embodiments can utilize lead, tungsten, and/or various lead alloys for grid fabrication, but also can include the practice of loading various binders or alloys with dense powder metals, such as tungsten. The binders can be epoxies, polymers, and/or dense alloys which are described in detail below. For certain exemplary embodiments, lead can be used for casting purposes because of its high density and low melting point, which can allow the molten lead to be poured or injected into a mold. In certain situations, however, pure lead can shrink and/or pull away from molds when it solidifies, which can inhibit the casting of fine features. This can be overcome by using lead alloys, made from high-density materials, which can allow the metal alloy to flow at lower temperatures than pure lead while reducing shrink factors. A typical chief component in a lead alloy is bismuth, a heavy, coarse crystalline metal that can expand by 3.3% of its volume when it solidifies. The presence of bismuth can expand and/or push the alloy into the fine features of the mold, thus enabling the duplication of fine features. The chart below shows the physical properties of pure lead and two lead alloys that were used to produce collimators. The alloys were obtained from Cerro Metal Products Co. of Bellefonte, Pa. Many other alloys exist that can be used to address specific casting and application requirements. BASE MELTMATERIALCOMPOSITIONPOINTDENSITY (g/cc)Pure LeadPb621.7 11.35degrees F.CERROBASE ™55.5% BI, 255 10.4444.5% Pbdegrees F.CERROLOW-117 ™44.7% BI, 22.6% 117 9.16Pb, 19.1% In,degrees F.8.3% Sn, 5.3% Cd, The physical properties of lead alloys can be more process-compatible when compared to pure lead, primarily because of the much lower melting point. For example, the low melt point of CERROBASE™ can allow the use of rubber-based molds, which can be helpful when casting fine-featured pieces. This can be offset in part by a slightly lower density (about 8%). The somewhat lower density, can be compensated for, however, by designing the grid structure with an increased thickness and/or slightly wider septal walls. Also, the alloy can be loaded with dense powder metals, such as tungsten, gold, and/or tantalum, etc., to increase density. Similarly, epoxy binders can be loaded with a metallic powder such as, for example, powdered tungsten, which has a density of 19.35 grams per cubic centimeter. In this approach, tungsten particles ranging in size from 1-150 microns, can be mixed and distributed into a binder material. The binder material can be loaded with the tungsten powder at sufficient amounts needed to achieve densities ranging between 8 and 14 grams per cubic centimeter. The tungsten powder is commercially available through the Kulite Tungsten Corporation of East Rutherford N.J., in various particle sizes, at a current cost of approximately $20-$25 dollars per pound. The binders and metallic powders can be combined and engineered to satisfy specific application and process issues. For example, tungsten powder can be added to various epoxies and used for casting. The company BONDLINE™ of San Jose, Calif., designs and manufactures engineered adhesives, such as epoxies, using powdered metals. Such composite metal epoxies can be cured at room temperature, can have high shear strength, low coefficient of thermal expansion, and viscosities that can be suited for high-resolution casting. Powdered materials combined with epoxy can be stronger than lead or lead alloys, but can be somewhat lower in density, having net density ranging from 7-8 grams per cubic centimeter. This density range can be acceptable for some collimator applications. In applications where material density is critical the practice of loading a lead alloy can be used. For example, tungsten powder can be combined with CERROBASE™ to raise the net density of the casting material from 10.44 up to 14.0 grams per cubic centimeter. Certain exemplary embodiments also include the casting of grid structures from ceramic materials, such as alumina, silicon carbide, zirconium oxide, and/or fused silica. Such ceramic grid structures can be used to segment radiation imaging detector elements, such as scintillators. The Cotronics Corporation of Brooklyn, N.Y., manufactures and commercially distributes Rescor™ Cer-Cast ceramics that can be cast at room temperature, can have working times of 30-45 minutes, can have cure times of 16 hours, and can withstand temperatures ranging from 2300 to 4000 degrees F. One or more exemplary embodiments can provide cellular air cross grids for blocking scattered X-ray radiation in mammography applications. Such cross grids can be interposed between the breast and the film-screen or digital detector. In some situations, such cross grids can tend to pass only the primary, information-containing radiation to the film-screen while absorbing secondary and/or scattered radiation which typically contains no useful information about the breast being irradiated. Certain exemplary embodiments can provide focused grids. Grids can be made to focus to a line or a point. That is, each wall defining the grid can be placed at a unique angle, so that if an imaginary plane were extended from each seemingly parallel wall, all such planes would converge on a line or a point at a specific distance above the grid center—the distance of that point from the grid known as the grid focal distance. A focused grid can allow the primary radiation from the x-ray source to pass through the grid, producing the desired image, while the off-axis scattered rays are absorbed by the walls of the grid (known as septal walls). In certain embodiments, the septal walls can be thick enough to absorb the scattered x-rays, but also can be as thin as possible to optimize the transmission ratio (i.e., the percentage of open cell area to the total grid area including septal walls) and minimize grid artifacts (the shadow pattern of grid lines on the x-ray image) in the radiograph. The relation of the height of the septal walls to the distance between the walls can be known as the grid ratio. Higher grid ratios can yield a higher scatter reduction capability, and thus a higher Contrast Improvement Factor (CIF), which can be defined as the ratio of the image contrast with and without a grid. A higher grid ratio can require, however, a longer exposure time to obtain the same contrast, thus potentially exposing the patient to more radiation. This dose penalty, known as the Bucky factor (BF), is given by BF=CIF/Tp, where Tp is the fraction of primary radiation transmitted. Certain exemplary embodiments can provide a grid design that arrives at an optimal and/or near-optimal combination of these measures. One or more exemplary embodiments can include fine-celled, focused, and/or large area molded cross-grids, which can be sturdily formed from a laminated mold formed of laminated layers of metal selectively etched by chemical milling or photo-etching techniques to provide open focused passages through the laminated stack of etched metal layers. In certain applications, such molded and/or cast cross grids can maximize contrast and accuracy of the resulting mammograms when produced with a standard radiation dosage. In certain exemplary embodiments, the laminated mold for the molded cross grids can be fabricated using adhesive or diffusion bonding to join abutting edges of thin partition portions of the laminated abutting layers with minimum intrusion of bonding material into the open focused passages. Exemplary embodiments can utilize any of a wide number of different materials to fabricate such molded and/or cast cross grids. A specific application can result in any of the following materials being most appropriate, depending on, for example, the net density and the cell and septa size requirements: Lead or lead alloy alone can offer a density of 9-11 grams per cc; Lead alloy can be loaded with a dense composite (e.g., tungsten, tantalum, and/or gold, etc.) powder to form a composite having a density of 12-15 grams per cc; Polymer can be loaded with a dense composite (e.g., lead, tungsten, tantalum, and/or gold, etc.) powder to form a composite having a density of 8-9 grams per cc; The cast grid made of lead alloy or any of the above combinations can be encapsulated in a low density polymer such that the transmission is minimally affected but scatter is significantly reduced. In addition, certain embodiments can be employed to fabricate grids and/or collimators for which the mold can be pre-loaded with dense powder, followed by alloy or polymer. Alternatively, polymer or alloy can be pre-loaded with dense powder then injected into the mold. In certain embodiments, the casting can be removed from a flexible mold. In other embodiments, the mold can be dissolved or consumed to de-mold the casting. In certain embodiments, a master can be removed layer-by-layer from rigid mold. Alternatively, the lost wax approach can be used in which the model is dissolvable wax, dissolvable PMMA, dissolvable polyurethane, dissolvable high-resolution ceramic, and/or some other dissolvable material. Certain exemplary embodiments can provide a system that includes an x-ray source, a scatter collimator, and a radiation detector array having a plurality of reflective scintillators. Such a system can be used for computer-assisted tomography (“CT”). Computed tomography is often performed using a CT scanner, which can also be known as a CAT scanner. In certain embodiments, the CT scanner can look like a large doughnut, having a square outer perimeter and a round hole. The patient can be positioned in a prone position on a table that can be adjusted up and down, and can be slid into and out of the hole of the CT scanner. Within the chassis of the CT scanner is an x-ray tube on a rotating gantry which can rotate around the patient's body to produce the images. On the opposite side of the gantry from the x-ray tube can be mounted an array of x-ray detectors. In certain exemplary embodiments, the x-ray source can project a fan-shaped beam, which can be collimated to lie within an X-Y plane of a Cartesian coordinate system, referred to as the “imaging plane”. The x-ray beam can pass through the object being imaged, such as a patient. The beam, after being attenuated by the object, can impinge upon the array of radiation detectors. The intensity of the attenuated beam radiation received at the detector array can be dependent upon the attenuation of the x-ray beam by the object. Each detector element of the array can produce a separate electrical signal that can provide a measurement of the beam attenuation at the detector location. The attenuation measurements from all the detectors can be acquired separately to produce an x-ray transmission profile of the object. For certain exemplary embodiments, the detector array can include a plurality of detector elements, and can be configured to attach to the housing. The detector elements can include scintillation elements, or scintillators, which can be coated with a light-retaining material. Moreover, in certain exemplary embodiments, the scintillators can be coated with a dielectric coating to contain within the scintillators any light events generated in the scintillators. Such coated scintillators can reduce detector element output gain loss, and thereby can extend the operational life of a detector element and/or array, without significantly increasing the costs of detector elements or detector arrays. In certain exemplary embodiments, the x-ray source and the detector array can be rotated with a gantry within the imaging plane and around the object to be imaged so that the angle at which the x-ray beam intersects the object can constantly change. A group of x-ray attenuation measurements, i.e., projection data, from the detector array at one gantry angle can be referred to as a “view”, and a “scan” of the object can comprise a set of views made at different gantry angles during one revolution of the x-ray source and detector. In an axial scan, the projection data can be processed to construct an image that corresponds to a two-dimensional slice taken through the object. In certain exemplary embodiments, images can be reconstructed from a set of projection data according to the “filtered back projection technique”. This process can convert the attenuation measurements from a scan into integers called “CT numbers” or “Hounsfield units”, which can be used to control the brightness of a corresponding pixel on a cathode ray tube display. In certain exemplary embodiments, detector elements can be configured to perform optimally when impinged by x-rays traveling a straight path from the x-ray source to the detector elements. Particularly, exemplary detector elements can include scintillation crystals that can generate light events when impinged by an x-ray beam. These light events can be output from each detector element and can be directed to photoelectrically responsive materials in order to produce an electrical signal representative of the attenuated beam radiation received at the detector element. The light events can be output to photomultipliers or photodiodes that can produce individual analog outputs. Exemplary detector elements can output a strong signal in response to impact by a straight path x-ray beam. Without a collimator, X-rays can scatter when passing through the object being imaged. Particularly, the object can cause some, but not all, x-rays to deviate from the straight path between the x-ray source and the detector. Therefore, detector elements can be impinged by x-ray beams at varying angles. System performance can be degraded when detector elements are impinged by these scattered x-rays. When a detector element is subjected to multiple x-rays at varying angles, the scintillation crystal can generate multiple light events. The light events corresponding to the scattered x-rays can generate noise in the scintillation crystal output, and thus can cause artifacts in the resulting image of the object. To, for example, reduce the effects of scattered x-rays, scatter collimators can be disposed between the object of interest and the detector array. Such collimators can be constructed of x-ray absorbent material and can be positioned so that scattered x-rays are substantially absorbed before impinging upon the detector array. Such scatter collimators can be properly aligned with both the x-ray source and the detector elements so that substantially only straight path x-rays impinge on the detector elements. Also, such scatter collimators can shield from x-ray radiation damage certain detector elements that can be sensitive at certain locations, such as the detector element edges. Certain exemplary embodiments of a scatter collimator can include a plurality of substantially parallel attenuating blades and a plurality of substantially parallel attenuating wires located within a housing. In certain exemplary embodiments, the attenuating blades, and thus the openings between adjacent attenuating blades, can be oriented substantially on a radial line emanating from the x-ray source. That is, each blade and opening can be focally aligned. The blades also can be radially aligned with the x-ray source. That is, each blade can be equidistant from the x-ray source. Scattered x-rays, that is, x-rays diverted from radial lines, can be attenuated by the blades. The attenuating wires can be oriented substantially perpendicular to the blades. The wires and blades thus can form a two-dimensional shielding grid for attenuating scattered x-rays and shielding the detector array. At least one embodiment of the invention can include a feature that provides any of at least 5 functions: 1) separation of the collimator by a predetermined distance from an array of radiation detection elements; 2) alignment of the collimator to the array of radiation detection elements (or vice versa); 3) attachment of the collimator to the array of radiation detection elements; 4) attach the collimator to a gantry or other detector sub-assembly; and/or 5) align the collimator to a gantry or other detector sub-assembly. As an illustrative example, one embodiment of such a feature could resemble “stilts” that can be formed independently or integrally to a collimator and that can separate the collimator by a predetermined distance from an array of radiation detection elements. In another embodiment, one or more of the stilts could serve as an alignment pin to align the collimator with the array of radiation detection elements. In another embodiment, one or more of the stilts could include and/or interface with an attachment mechanism to attach the collimator to the array of radiation detection elements. For example, an end of a stilt could slide into, via an interference fit, a socket of the array of radiation detection elements. As example, a stilt could include a hemispherical protrusion that snaps into a corresponding hemispherical indentation in a socket of the array of radiation detection elements. As another illustrative example, one embodiment of such a feature could invert the description of the previous paragraph by providing “holes” in the collimator that interface with “stilts” attached to or integral with the radiation detection elements. As yet another illustrative example, an embodiment of the feature could be manifested in a collimator having an array of through-holes, each having a square cross-section. At one end of all or certain through-holes could be the feature, such as a groove that extends around a perimeter of the square through-hole. A radiation detection element could have a square outer perimeter that includes a lip having corresponding dimensions to the groove that allows the radiation detection element to snap into the through-hole of the collimator via an interference fit, thereby fixing the position of the radiation detection element with respect to the collimator, aligning the radiation detection element with the collimator, and attaching the radiation detection element to the collimator. Moreover, a modular collection of radiation detection elements, potentially cast according to an embodiment, could attach to a collimator via one or more attachment features, any of which could be formed independently of, or integrally with, either the radiation detection module and/or the collimator. Depending on the embodiment, the scatter collimator can include blades and wires, open air cells, and/or encapsulated cells. Certain exemplary embodiments can be fabricated as a true cross grid having septa in both radial and axial directions. The cross-grid structure can be aligned in the radial and axial directions or it can be rotated. Thus, the cross grid can be aligned in two orthogonal directions. Depending on the grid design, it might not be practical and/or possible to remove the mold from the cast grid because of its shape or size, e.g., if very thin septa or severe undercuts are involved. In such cases, a material with a low x-ray absorptivity can be used for the mold and the final grid can be left encapsulated within the mold. Materials used for encapsulation can include, but are not limited to, polyurethanes, acrylics, foam, plastics etc. Because certain exemplary embodiments can utilize photolithography in creating the laminated mold, great flexibility can be possible in designing the shape of the open cells. Thus, round, square, hexagonal, and/or other shapes can be incorporated. Furthermore, the cells do not all need to be identical (a “redundant pattern”). Instead, they can vary in size, shape, and/or location (“non-redundant” pattern) as desired by the designer. In addition, because of the precision stack lamination of individual layers that can be employed in fabricating the master, the cell shapes can vary in the third dimension, potentially resulting in focused, tapered, and/or other shaped sidewalls going through the cell. Because the cell shape can vary in the third dimension (i.e. going through the cell), the septa wall shape can also vary. For example, the septa can have straight, tapered, focused, bulging, and/or other possible shapes. Furthermore, the septa do not all need to be identical (a “redundant pattern”). Instead, they can vary in cross-sectional shape (“non-redundant” pattern) as desired by the designer. Certain exemplary embodiments can provide a collimator or section of a collimator as a single cast piece, which can be inherently stronger than either a laminated structure or an assembly of precisely machined individual pieces. Such a cast collimator can be designed to withstand any mechanical damage from the significant g-forces involved in the gantry structure that can rotate as fast as 4 revolutions per second. Furthermore, such a cast structure can be substantially physically stable with respect to the alignment between collimator cells and detector elements. Some exemplary embodiments can provide a collimator or section of a collimator as a single cast collimator in which cells and/or cell walls can be focused in the radial direction, and/or in which cells and/or cells walls can be accurately aligned in the axial direction. Conversely, certain exemplary embodiments can provide a collimator or section of a collimator as a single cast collimator in which cells and/or cell walls can be focused (by stacking layers having slightly offset openings) in the axial direction, and/or in which cells and/or cells walls can be curved (and focused) in the radial direction. Exemplary embodiments can utilize any of a wide number of different materials to fabricate the scatter collimator. A specific application can result in any of the following materials being most appropriate, depending on, for example, the net density and the cell and septa size requirements. Lead or lead alloy alone can offer a density of 9-11 grams per cc; Lead alloy can be loaded with a dense composite (e.g., tungsten, tantalum, and/or gold, etc.) powder to form a composite having a density of 12-15 grams per cc; Polymer can be loaded with a dense composite (e.g., lead, tungsten, tantalum, and/or gold, etc.) powder to form a composite having a density of 8-9 grams per cc; The cast grid made of lead alloy or any of the above combinations can be encapsulated in a low density polymer such that the transmission is minimally affected but scatter is significantly reduced. In addition, certain embodiments can be employed to fabricate grids and/or collimators for which the mold can be pre-loaded with dense powder, followed by alloy or polymer. Alternatively, polymer or alloy can be pre-loaded with dense powder then injected into the mold. In certain embodiments, the casting can be removed from a flexible mold. In other embodiments, the mold can be dissolved or consumed to de-mold the casting. In certain embodiments, a master can be removed layer-by-layer from rigid mold. Alternatively, the lost wax approach can be used in which the model is dissolvable wax, dissolvable PMMA, dissolvable polyurethane, dissolvable high-resolution ceramic, and/or some other dissolvable material. The above description and examples have covered a number of aspects of certain exemplary embodiments of the invention including, for example, cell size and shape, different materials and densities, planar and non-planar orientations, and focused and unfocused collimators. In conventional X-ray or CT examinations, the radiation is emitted by a machine and then passes through the patient's body. In nuclear medicine exams, however, a radioactive material is introduced into the patient's body (by injection, inhalation or swallowing), and is then detected by a machine, such as a gamma camera or a scintillation camera. The camera can have a detector and means to compute the detected image. The detector can have at least one a scintillator crystal, which typically is planar. The scintillator can absorb the gamma radioactive radiation, and emit a luminous scintillation in response, which can be detected by an array of photomultiplier tubes of the detector. The computation means can determine the coordinates of a locus of interaction of the gamma rays in the scintillator, which can reveal the projected image of the body. Because the radiation source in the patient can emit radiation omnidirectionally, a collimator can be located between the body and the scintillator. This collimator can prevent the transmission of those radioactive rays that are not propagating in a chosen direction. Certain embodiments can be used to fabricate structures useful for nuclear medicine. For example, collimators used in nuclear medicine, including pinhole, parallel-hole, diverging, and converging collimators, can be fabricated according to one or more exemplary methods. As another example, exemplary methods can be used to fabricate high precision, high attenuation collimators with design flexibility for hole-format, which can improve the performance of pixelated gamma detectors. Certain exemplary embodiments of certain casting techniques can be applied to the fabrication of other components in detector systems. FIG. 47 is an assembly view of components of a typical pixelated gamma camera. Embodiments of certain casting techniques can be used to produce collimator 47010, scintillator crystals segmentation structure 47020, and optical interface 47030 between scintillator array (not visible) and photo-multiplier tubes 47040. In an exemplary embodiment, collimator 47010 can be fabricated from lead, scintillator crystals segmentation structure 47020 can be fabricated from a ceramic, and optical interface 47030 can be fabricated from acrylic. In certain exemplary embodiments, through the use of a common fabrication process, two or more of these components can be made to the same precision and/or positional accuracy. Moreover, two or more of these components can be designed to optimize and/or manage seams and/or dead spaces between elements, thereby potentially improving detector efficiency for a given choice of spatial resolution. For example, in a pixelated camera with non-matched detector and collimator, if the detector's open area fraction (the fraction of the detector surface that is made up of converter rather than inter-converter gap) is 0.75, and the collimator's open area fraction (the fraction of the collimator surface that is hole rather than septum) is 0.75, the overall open area fraction is approximately (0.75)=0.56. For a similar camera in which the collimator holes are directly aligned with the pixel converters, the open area fraction is 0.75, giving a 33% increase in detection efficiency without reduction in spatial resolution. Certain embodiments can provide parallel hole collimators and/or collimators having non-parallel holes, such as fan beam, cone beam, and/or slant hole collimators. Because certain embodiments use photolithography in creating the master, flexibility is possible in designing the shape, spacing, and/or location of the open cells. For example, round, square, hexagonal, or other shapes can be incorporated. In addition, because certain embodiments use precision stack lamination of individual layers to fabricate a laminated mold, the cell shapes can vary in the third dimension, resulting in focused, tapered, and/or other shaped sidewalls going through the cell. Furthermore, the cells do not all need to be identical (“redundant”). Instead, they can vary in size, shape or location (“non-redundant”) as desired by the designer, which in some circumstances can compensate for edge effects. Also, because a flexible mold can be used with certain embodiments, collimators having non-planar surfaces can be fabricated. In some cases, both surfaces are non-planar. However, certain embodiments also allow one or more surfaces to be planar and others non-planar if desired. Certain embodiments can fabricate a collimator, or section of a collimator, as a single cast piece, which can make the collimator less susceptible to mechanical damage, more structurally stable, and/or allow more accurate alignment of the collimator with the detector. Certain embodiments can utilize any of a number of different materials to fabricate a collimator or other component of an imaging system. A specific application could result in any of the following materials being chosen, depending, in the case of a collimator, on the net density and the cell and septa size requirements: Lead or lead alloy alone can offer a density of 9-11 grams per cc Polymer can be loaded with tungsten powder to form a composite having a density comparable to lead or lead alloys Polymer can also be combined with other dense powder composites such as tantalum or gold to yield a density comparable to lead or lead alloys Polymer can be combined with two or more dense powders to form a composite having a density comparable to lead or lead alloys Lead alloy can be loaded with tungsten powder to form a composite having a density of 12-15 grams per cc Lead alloy can be loaded with another dense composites (tantalum, gold, other) to form a composite having a density of 12-15 grams per cc Lead alloy can be combined with two or more dense powders to form composites having a density of 12-15 grams per cc (atomic number and attenuation) The cast grid made of lead alloy or any of the above combinations can be encapsulated in a low-density material such that the transmission is minimally affected but scatter is reduced. Thus, depending on the specific application, certain embodiments can create any of a wide range of densities for the cast parts. For example, by adding tungsten (or other very dense powders) to lead alloys, net densities greater than that of lead can be achieved. In certain situations, the use of dense particles can provide high “z” properties (a measure of radiation absorption). For certain embodiments, as radiation absorption improves, finer septa walls can be made, which can increase imaging resolution and/or efficiency. In addition, certain embodiments can be employed to fabricate grids and/or collimators for which the mold can be pre-loaded with dense powder, followed by alloy or polymer. Alternatively, polymer or alloy can be pre-loaded with dense powder then injected into the mold. In certain embodiments, the casting can be removed from a flexible mold. In other embodiments, the mold can be dissolved or consumed to de-mold the casting. In certain embodiments, a master can be removed layer-by-layer from rigid mold. Alternatively, the lost wax approach can be used in which the model is dissolvable wax, dissolvable PMMA, dissolvable polyurethane, dissolvable high-resolution ceramic, and/or some other dissolvable material. With certain embodiments, the stack-laminated master does not need to embody the net density of the final grid. Instead, it can have approximately the same mechanical shape and size. Similarly, the final grid can be cast from relatively low cost materials such as lead alloys or polymers. Furthermore, these final grids can be loaded with tungsten or other dense powders. As discussed previously, using certain embodiments of the invention, multiple molds can be made from a single master and multiple grids can be cast at a time, if desired. Such an approach can lead to consistency of dimensions and/or geometries of the molds and/or grids. Because of the inherent precision of the lithographic process, certain embodiments can prevent and/or minimize assembly build up error, including error buildup across the surface of the grid and/or assembly buildup error as can occur in collimators in which each grid is individually assembled from photo-etched layers. In addition, process errors can be compensated for in designing the laminated mold. Step 1: Creating the laminated mold: In this exemplary process, 0.05 mm thick copper foils were chemically etched and then laminated together using a metal-to-metal brazing process, for producing a laminated mold. Photo-masks were configured with a 2.0×2.0 millimeter square open cell, with a 0.170 mm septal wall separating the cells. The cells were arrayed having 10 rows and 10 columns, with a 2 mm border around the cell array. Photo-masks were produced to the same specifications, by the same vendor as those described in example 1, step 1. The layers were designed so that the cell placement was identical from layer to layer, which when assembled, produced a parallel cross-sectional shape. FIG. 42A is a top view of an x-ray grid 42000 having an array of cells 42002 separated by septal walls 42004. FIG. 42B is a cross-sectional view of x-ray grid 42000 taken along section lines 42-42 of FIG. 42B showing that the placement of cells 42002 can also be dissimilar from layer to layer 42010-42050, so that when assembled, cells 42002 are focused specifically to a point source 42060 at a known distance from x-ray grid 42000. The total number of layers in the stack lamination defined the thickness of the casting mold and final cast grid. The final thickness of the lamination was specified at 0.118 inches, which required 57 layers of copper foil, leaving a total thickness amount of 0.00007 inches between each layer for a braze material. The layers were processed by Tech Etch of Plymouth Mass., using standard photo-etching techniques and were etched in such a way that the cross-sectional shape of the etched walls were perpendicular to the top and bottom surfaces of the foil (commonly referred to as straight sidewalls). The method chosen to bond the grid layers together was a metal-to-metal brazing technique described earlier in detail as one of two exemplary methods of bonding layers together (eutectic braze alloy). The brazed lamination was then electro-plated with a coating of hard nickel, also described earlier. Step 2: Creating a derived mold: An RTV mold was made from the stack laminated mold from step 1. Silastic® M RTV Silicone Rubber was chosen as the base material for the derived mold. This particular material was used to demonstrate the resolution capability, release properties, multiple castings, and dimensional repeatability of the derived mold from the laminated mold. Silastic M has the hardest durometer of the Silastic® family of mold making materials. The derived mold was configured as an open face mold. The fixture used to create the derived casting mold is shown in FIG. 32 and was comprised of a precision machined aluminum ring 32010, precision ground glass plates 32020 and 32030, rubber gaskets 32040 and 32050, and the laminated mold 32060. The base of the fixture 32020 was a 5 inch square of 1 inch thick Plexiglas. On the top surface of the Plexiglas base was a 1″ thick, 3 inch diameter glass substrate 32030. The base and the glass substrate were separated by a 1/16 inch thick, 4.5 inch diameter rubber gasket 32040. An additional 3.0 inch rubber gasket 32050 was placed on the top surface of the glass substrate 32030. The rubber gaskets helped prevent unwanted flashing of molten material when casting. The laminated mold 32060 was placed on the top gasket. The shape and thickness of the glass created the entrance area where the casting material was poured into the mold. The material formed in this cavity was referred to as a controlled backing. It served as a release aid for the final casting, and could later be removed from the casting in a final machining process. A precision machined aluminum ring 32010 having a 4.5 inch outside diameter and a 4 inch inside diameter was placed over the master subassembly and interfaced with the lower 4.5 inch diameter rubber gasket. As illustrated in FIG. 32, the height of the ring was configured so that the distance from the top surface of the master to the top of the ring was twice the distance from the base of the fixture to the top of the laminated mold. The additional height allowed the RTV material to rise up during the degassing process. The ring portion of the fixture assembly was used to locate the pouring of the mold material into the assembly, captivate the material during the curing process, and provide an air escape while the mold material was degassed using vacuum. The fixture was configured in such a way that all sides surrounding the laminated mold were equal and common, in order to limit the effects or stresses put on the lamination from the mold material. The Silastic® M RTV Silicone Rubber used for the mold fabrication was prepared in accordance with the manufacturer's recommendations, using the process described earlier in example 1, step 2. The laminated mold was characterized, before and after the mold-making process, by measuring the average pitch distance of the cells, the septal wall widths, overall distance of the open grid area, and the finished thickness of the part. These dimensions were also measured on the derived casting mold and compared with the laminated mold before and after the mold-making process. The following chart lists the dimensions of the lamination before and after the mold-making and the same dimensions of the derived RTV mold. All dimensions were taken using a Nikon MM-11 measuring scope at 200× magnification. These dimensions demonstrated the survivability of the master and the dimensional repeatability of the mold. Master Master LaminationLaminationGrid (before RTV Mold(after Featuremold-making)Silastic ® Mmold-making)Septal Wall Width (mm) 0.170 0.161 0.170Cell Width (mm) 2.000 × 2.000 2.010 × 2.010 2.000 × 2.000Cell Pitch (mm) 2.170 × 2.170 2.171 × 2.171 2.170 × 2.170Pattern area (mm)21.530 × 21.53021.549 × 21.54921.530 × 21.530Thickness (mm) 2.862 2.833 2.862 Step 3: Casting the final collimator: A fine-featured lead collimator was produced from the derived RTV silicone mold described in step 2. FIG. 43 is a side view of an assembly 43000 that includes an open face mold 43010 that was used to produce a casting 43020 from CERROBASE™ alloy. Casting 43020 was dimensionally measured and compared to the laminated mold 43010. The backing 43030 of casting 43020 was 6 millimeters in thickness and was removed using a machining process. Grid FeaturesMaster Lamination Cast CollimatorSeptal Wall Width (mm)0.1700.165Cell Width (mm)2.000 × 2.0002.005 × 2.005Cell Pitch (mm)2.170 × 2.1702.170 × 2.170 The first step of the casting process was to pre-heat the derived RTV mold to a temperature of 275 degrees F., which was 20 degrees above the melting point of the CERROBASE™ alloy. The mold was placed on a heated aluminum substrate, which maintained the mold at approximately 275 degrees F. when it was placed in the vacuum bell jar. In certain casting procedures, the material can be forced into the mold in a rapid fashion, and cooled and removed quickly. In this case, the casting process was somewhat slowed in order to fully fill and evacuate the air from the complex cavity geometry of the mold. The CERROBASE™ was then heated in an electric melting pot to a temperature of 400 degrees F., which melted the alloy sufficiently above its melt point to remain molten during the casting process. The next step was to pour the molten alloy into the mold, in such a way as to aid in the displacement of any air in the cavity. This was accomplished by tilting the mold at a slight angle and beginning the pour at the lowest point in the cavity section of the mold. It was found that if the mold was placed in a flat orientation while pouring the molten alloy, significant amounts of air were trapped, creating problems in the degassing phase of the process. Instead, once the mold was sufficiently filled with the molten alloy, the mold was slightly vibrated or tapped in order to expel the largest pockets of air. The mold, on the heated aluminum substrate, was then placed in the vacuum bell jar, pumped down to atmosphere of 25-28 inches of mercury for 2 minutes, which was sufficient time to evacuate any remaining air pockets. The mold was then removed from the vacuum bell jar and submersed in a quenching tank filled with water cooled to a temperature of 50 degrees F. The rapid quench produced a fine crystalline grain structure when the casting material solidified. The casting was then removed from the flexible mold by grasping the backing 43030, by mechanical means or by hand, and breaking the casting free of the mold using an even rotational force, releasing the casting gradually from the mold. The final process step was removing the backing 43030 from the attached surface of the grid casting 43020 to the line shown in FIG. 43. Prior to removing the backing, the grid structure of the final casting 43020 was filled or potted with a machinable wax, which provided the structural integrity needed to machine the backing without distorting the fine walls of the grid casting. The wax was sold under the product name MASTER™ Water Soluble Wax by the Kindt-Collins Corporation, of Cleveland, Ohio. The wax was melted at a temperature of 160-180 degrees F., and poured into the open cells of the cast grid. Using the same technique described above, the wax potted casting was placed in vacuum bell jar and air evacuated before being cooled. The wax was cooled to room temperature and was then ready for the machining of the backing. A conventional surface grinder was used to first rough cut the backing from the lead alloy casting. The remaining casting was then placed on a lapping machine and lapped on the non-backing side of the casting using a fine abrasive compound and lapping wheel. The non-backing side of the casting was lapped first so that the surface was flat and parallel to within 0.010-0.015 millimeters to the adjacent cast grid cells. The rough-cut backing surface was then lapped using the same abrasive wheel and compound so that it was flat and parallel to within 0.100-0.015 millimeters of the non-backing side of the casting. A thickness of 2.750 millimeters was targeted as the final casting thickness. Upon completion of the lapping process, the casting was placed in an acid solution, comprised of 5% dilute HCl and water, with mild agitation until the wax was fully dissolved from the cells of the casting. In an alternative embodiment, individual castings could also be stacked, aligned, and/or bonded to achieve thicker, higher aspect ratio collimators. Such collimators, potentially having a thicknesses measured in centimeters, can be used in nuclear medicine. A non-planar collimator can have several applications, such as, for example, in a CT environment. To create such an example of such a collimator, the following process was followed: Step 1: Creating a laminated mold: For this example, a laminated mold was designed and fabricated using the same process and vendors described in Example 1, step 1. The laminated mold was designed to serve as the basis for a derived non-planar casting mold. The laminated mold was designed and fabricated with outside dimensions of 73.66 mm×46.66 mm, a 5 mm border around a grid area having 52×18 open cell array. The cells were 1 mm×1.980 mm separated by 0.203 septal walls. The layers for the laminated mold were bonded using the same process described in Example 1, step 1 (thermo-cured epoxy). The dimensions of the laminated mold were specified to represent a typical collimator for CT x-ray scanning Silastic® J RTV Silicone Rubber was chosen as a base material to create a derived non-planar casting mold because of its durometer which allowed it to more easily be formed into a non-planar configuration. The laminated mold and fixture was configured as an open face mold. Step 2: Creating a derived non-planar mold: Silastic® J RTV Silicone Rubber was used for the derived mold fabrication and was prepared in accordance with the manufacturers recommendations, using the process described earlier in example 1, step 2. FIG. 44 is a top view of casting assembly 44000. FIG. 45 is a side view of casting assembly 44000. The derived RTV mold 44010 was then formed into a non-planar configuration as shown in FIG. 45. The surface 44020 of casting fixture base 44030 defined a 1-meter radius arc to which mold 44010 was attached. A 1-meter radius was chosen because it is a common distance from the x-ray tube to the collimator in a CT scanner. Mold 44010 was fastened to the convex surface 44020 of casting base 44030 with a high temperature epoxy adhesive. A pour frame 44040 was placed around casting fixture base 44030. Pour frame 44040 had an open top to allow pouring the casting material to a desired fill level and to allow evacuating the air from the casting material. The laminated mold was characterized, before and after producing the derived non-planar mold, by measuring the average pitch distance of the cells, the septal wall widths, overall distance of the open grid area, and the finished thickness of the part. These dimensions were also measured on the derived non-planar mold and compared with the master before and after the mold-making process. The following chart lists the dimensions of the master lamination before and after the mold-making and the same dimensions of the RTV mold in the planar state and curved state. All dimensions are in millimeters and were taken using a Nikon MM-11 measuring scope at 200× magnification. Master LaminationRTV Mold RTV Mold (before mold-(planar)(curved)Grid Featuresmaking)Silastic ® JSilastic ® JSeptal Wall 0.203 0.183 0.193*Cell Width 1.980 × 1.000 2.000 × 1.020 2.000 × 1.020Cell Pitch 2.183 × 1.203 2.183 × 1.203 2.183 × 1.213Pattern area 39.091 × 62.35339.111 × 62.37339.111 × 62.883Thickness 7.620 7.544 7.544*measured in the direction of curvature. Step 3: Casting a non-planar collimator: The derived non-planar RTV mold described in step 2, was used to create castings. Using the derived non-planar mold, the castings were produced from CERROBASE™ alloy and were dimensionally measured and compared to the laminated mold. Grid FeaturesMaster LaminationCast CollimatorSeptal Wall Width (mm)0.2030.197 *Cell Width (mm)1.000 × 1.9801.006 × 1.986Cell Pitch (mm)1.203 × 2.1831.203 × 2.183* measured in the direction of curvature. The process used to fill the derived non-planar mold with the casting alloy and the de-molding of the casting was the same process described in Example 6. The final process step included the removal of the backing from the grid casting. A wire EDM (electrode discharge machining) process was found to be the most effective way to remove the backing from the casting, primarily due to the curved configuration of the casting. The wire EDM process used an electrically charged wire to burn or cut through the casting material, while putting no physical forces on the parts. In this case, a fine 0.003 inch molybdenum wire was used to cut the part, at a cutting speed of 1 linear inch per minute. This EDM configuration was chosen to limit the amount of recast material left behind on the cut surface of the part, leaving the finished septal walls with a smooth surface finish. The casting was fixtured and orientated so that the radial cutting of the backing was held parallel to the curved surface of the casting, which was a 1 meter radius. Another exemplary application of embodiments is the fabrication of a mammography scatter reduction grid. In this example, a derived clear urethane mold for a fine-featured focused grid was made using a photo-etched stack lamination for the master model. For making this mold, the master was designed and fabricated using the lamination process detailed in Example 7. A clear urethane casting material was chosen as an example of a cast grid in which the mold was left intact with the casting as an integral part of the grid structure. This provided added strength and eliminated the need for a fragile or angled casting to be removed from the mold. Step 1: Creating a laminated mold: The laminated mold was fabricated from photo-etched layers of copper. The mold was designed to have a 63 mm outside diameter, a 5 mm border around the outside of the part, and a focused 53 mm grid area. FIG. 46 is a top view of a grid area 46000, which was comprised of hexagonal cells 46010 that were 0.445 mm wide, separated by 0.038 mm septal walls 46020. The cells were focused from the center of the grid pattern to a focal point of 60 centimeters, similar to that shown in FIG. 42B. The grid was made from 35 layers of 0.050 mm thick stainless steel, which when assembled created a 4:1 grid ratio. Each grid layer utilized a separate photo-mask in which the cells are arrayed out from the center of the grid pattern at a slightly larger distance from layer to layer. This created the focused geometry as shown in FIG. 42B. With this cell configuration, the final casting produced a hexagonal focused grid with a transmission of about 82%. The photo-masks and etched layers were produced using the same vendors and processes described in example 1, steel. Step 2: Creating a derived urethane mold: Urethane mold material was chosen for its high-resolution, low shrink factor, and low density. Because of its low density, the urethane is somewhat transparent to the transmission of x-rays. The mold material, properties, and process parameters were as described earlier in example 4, step 4. The fixture used to create the derived urethane casting mold was the same as that described in Example 6, step 2. Before assembling the mold fixture, the laminated mold was sprayed with a mold release, Stoner E236. The fixture was assembled as shown in FIG. 32 and heated to 125 degrees F. Then it was filled with the Water Clear urethane and processed using the same parameters described in example 4, step 4. The laminated mold was characterized, before and after making the derived mold, by measuring the average pitch distance of the cells, the septal wall widths, overall distance of the open grid area, and the finished thickness of the lamination. These dimensions were also measured on the derived urethane casting mold and compared with the lamination before and after the mold-making process. The following chart lists the dimensions of the lamination before and after the mold-making and the same dimensions of the urethane mold. All dimensions were in millimeters and were taken using a Nikon MM-11 measuring scope at 200× magnification. Master Urethane Casting Master LaminationSystemLaminationGrid (before mold-Water (after mold-Featuresmaking) Clearmaking)Septal Wall Width 0.0380.0370.038Cell Width0.445 0.446 0.445 (hexagonal)(hexagonal)(hexagonal)Cell Pitch0.4830.4830.483Pattern area (mm2)53.00052.73553.000Thickness1.7501.7291.750 Step 3: Casting the anti-scatter grid: A focused scatter reduction grid was produced by casting a lead alloy, CERROLOW-117™ alloy into the derived urethane mold described in step 2. The backing thickness of the casting was 2 millimeters and was removed using a surface grinding process. The first step of the process was to pre-heat the derived urethane mold to a temperature of 137 degrees F., which was 20 degrees above the 117 degree melting point of the CERROLOW™ alloy. The mold was placed on a heated aluminum substrate, which maintained the mold to approximately 117 degrees F. when it was placed in the vacuum bell jar. The CERROLOW™ was then heated in an electric melting pot to a temperature of 120 degrees F., which melted the alloy sufficiently above the melt point of the material, keeping the material molten during the casting process. The process steps for filling the mold were the same as those described in Example 6, step 3. The CERROLOW™ alloy was chosen for casting because of its high resolution capability, low melting point, and relatively high density. The urethane mold was left remaining to provide structural integrity for the fine lead alloy features. The urethane is also somewhat transparent to x-rays because of its low density (1 g/cm3) compared to the casting alloy. Additional collimator samples have been produced using the same process described in Example 6 above, with the exception of the casting alloy and that it was loaded with tungsten powder prior to the casting process. The tungsten powder (KMP115) was purchased through the Kulite Tungsten Corporation of East Rutherford, N.J. CERROLOW™ alloy was loaded to raise the net density of the alloy from a density of 9.16 grams per cubic centimeter to 13 grams per cubic centimeter. In certain radiological applications, elimination of secondary scattered radiation, also known as Compton scatter, and shielding can be an objective. The base density of the CERROLOW™ alloy can be sufficient on its own to absorb the scattered radiation, but the presence of the tungsten particles in the septal walls can increase the density and improve the scatter reduction performance of the part. The casting was dimensionally measured and compared to the laminated mold used to create the derived RTV mold. Grid FeaturesMaster LaminationCast CollimatorMaterialCopperCERROLOW-117 PlusTungsten PowderDensity (g/cc)8.9612.50Septal Wall Width0.0380.036Cell Width0.445 0.447 (hexagonal)(hexagonal)Cell Pitch0.4830.483*all dimensions are in millimeters. Prior to casting, the tungsten powder was loaded or mixed into the CERROLOW™ alloy. The first step was to super-heat the alloy to 2-3 times its melting point temperature (between 234-351 degrees F.), and to maintain this temperature. The tungsten powder, having particle sizes ranging from 1-15 microns in size, was measured by weight to 50% of the base alloy weight in a furnace crucible. A resin-based, lead-compatible soldering flux was added to the tungsten powder to serve as a wetting agent when combining the powder and the alloy. The resin flux was obtained from the Indium Corporation of America of Utica N.Y., under the name Indalloy Flux # 5RMA. The flux and the powder were heated to a temperature of 200 degrees F. and mixed together after the flux became liquid. The heated CERROLOW™ alloy and the fluxed powder then were combined and mixed using a high-shear mixer at a constant temperature of 220 degrees F. The net density of the alloy loaded with the powder was measured at 12.5 grams per cubic centimeter. The loaded alloy was molded into the derived RTV mold, and finished machined using the same process described in Example 6. This example demonstrates a structure that could be co-aligned with a cast collimator. The structure could be filled with detector materials, such as a scintillator, for pixilation purposes. Ceramic was chosen for high temperature processing of the scintillator materials, which are normally crystals. Additional cast samples have been produced using a castable silica ceramic material using the same mold described in Example 7 above. The ceramic material, Rescor™-750, was obtained from the Cotronics Corporation of Brooklyn, N.Y. The ceramic material was prepared prior to casting per the manufacturer's instructions. This included mixing the ceramic powder with the supplied activator. Per the manufacturer's instructions, an additional 2% of activator was used to reduce the viscosity of the mixed casting ceramic, in order to aid in filling the fine cavity features of the mold. The mold was filled and degassed using a similar process and the same mold and non-planar fixture as Example 7 above, covered with a thin sheet of plastic, and allowed to cure for 16 hours at room temperature. The ceramic casting then was removed from the RTV mold and post cured to a temperature of 1750 degrees F., heated at a rate of 200 degrees F. per hour. Post-curing increased the strength of the cast grid structure. The ceramic casting then was ready for the final grinding and lapping process for the removal of the backing Additional Fields of Use Additional exemplary fields of use, illustrative functionalities and/or technology areas, and representative cast devices are contemplated for various embodiments of the invention, as partially listed below. Note that any such device, and many others not specifically listed, can utilize any aspect of any embodiment of the invention as disclosed herein to provide any of the functionalities in any of the fields of use. For example, in the automotive industry, inertial measurement can be provided by an accelerometer, at least a component of which that has been fabricated according to a method. Likewise, in the telecommunications field, one or more components of an optical switch, and possibly an entire optical switch, can be fabricated according to a method. Embodiments of such devices can provide any of a number of functionalities, including, for example, material, mechanical, thermal, fluidic, electrical, magnetic, optical, informational, physical, chemical, biological, and/or biochemical, etc. functionalities. Embodiments of such devices can at least in part rely on any of a number of phenomena, effects, and/or properties, including, for example, electrical, capacitance, inductance, resistance, piezoresistance, piezoelectric, electrostatic, electrokinetic, electrochemistry, electromagnetic, magnetic, hysteresis, signal propagation, chemical, hydrophilic, hydrophobic, Marangoni, phase change, heat transfer, fluidic, fluid mechanical, multiphase flow, free surface flow, surface tension, optical, optoelectronic, electro-optical, photonic, wave optic, diffusion, scattering, interference, diffraction, reflection, refraction, absorption, adsorption, mass transport, momentum transport, energy transport, species transport, mechanical, structural dynamic, dynamic, kinematic, vibration, damping, tribology, material, bimetallic, shape memory, biological, biochemical, cell transport, electrophoretic, physical, Newtonian, non-Newtonian, linear, non-linear, and/or quantum, etc. phenomena, effects, and/or properties. Moreover, note that unless stated otherwise, any device, discrete device component, and/or integrated device component fabricated according to any method disclosed herein can have any dimension, dimensional ratio, geometric shape, configuration, feature, attribute, material of construction, functionality, and/or property disclosed herein. Among the many contemplated industries and/or fields of use are: Aerospace Automotive Avionics Biotechnology Chemical Computer Consumer Products Defense Electronics Manufacturing Medical devices Medicine Military Optics Pharmaceuticals Process Security Telecommunications Transportation Among the many contemplated technology areas are: Acoustics Active structures and surfaces Adaptive optics Analytical instrumentation Angiography Arming and/or fusing Bio-computing Bio-filtration Biomedical imaging Biomedical sensors Biomedical technologies Cardiac and vascular technologies Catheter based technologies Chemical analysis Chemical processing Chemical testing Communications Computed tomography Computer hardware Control systems Data storage Display technologies Distributed control Distributed sensing DNA assays Electrical hardware Electronics Fastener mechanisms Fluid dynamics Fluidics Fluoroscopy Genomics Imaging Inertial measurement Information technologies Instrumentation Interventional radiography Ion source technologies Lab-on-a-chip Measurements Mechanical technologies Medical technologies Microbiology Micro-fluidics Micro-scale power generation Non-invasive surgical devices Optics Orthopedics Power generation Pressure measurement Printing Propulsion Proteomics Radiography RF (radio frequency) technologies Safety systems Satellite technologies Security technologies Signal analysis Signal detection Signal processing Surgery Telecommunications Testing Tissue engineering Turbomachinery Weapon safeing Among the many contemplated cast devices and/or cast device components are at least one: accelerometer actuator airway amplifier antenna aperture application specific microinstrument atomizer balloon catheter balloon cuff beam beam splitter bearing bioelectronic component bio-filter biosensor bistable microfluidic amplifier blade passage blower bubble capacitive sensor capacitor cell sorting membrane chain channel chromatograph clip clutch coextrusion coil collimator comb comb drive combustor compression bar compressor conductor cooler corrosion sensor current regulator density sensor detector array diaphragm diffractive grating diffractive lens diffractive phase plate diffractor diffuser disc display disposable sensor distillation column drainage tube dynamic value ear plug electric generator electrode array electronic component socket electrosurgical hand piece electrosurgical tubing exciter fan fastener feeding device filter filtration membrane flow passage flow regulator fluid coextrusion fluidic amplifier fluidic oscillator fluidic rectifier fluidic switch foil fuel cell fuel processor fuse gear grating grating light valve gyroscope hearing aid heat exchanger heater high reflection coating housing humidity sensor impeller inducer inductor infra-red radiation sensor infusion sleeve infusion test chamber interferometer introducer sheath introducer tip ion beam grid ion deposition device ion etching device jet joint lens lens array lenslet link lock lumen manifold mass exchanger mass sensor membrane microbubble microchannel plate microcombustor microlens micromirror micromirror display microprism microrelay microsatellite component microshutter microthruster microtiterplate microturbine microwell mirror mirror display mixer multiplexer nozzle optical attenuator optical collimator optical switch ordinance control device ordinance guidance device orifice phase shifter photonic switch pin array plunger polarizer port power regulator pressure regulator pressure sensor printer head printer head component prism processor processor socket propeller pump radiopaque marker radiopaque target rate sensor reaction chamber reaction well reactor receiver reflector refractor regulator relay resistor resonator RF switch rim safe-arm device satellite component scatter grid seal septum shroud shunt shutter spectrometer stent stopper supercharger switch tank temperature regulator temperature sensor thruster tissue scaffolding titerplate transmission component transmitter tunable laser turbine turbocharger ultra-sound transducer valve vane vessel vibration sensor viscosity sensor voltage regulator waveplate well wheel wire coextrusion Additional detailed examples of some of the many possible embodiments of devices and/or device components that can be fabricated according to a method are now provided. Additional potential embodiments of these and/or other contemplated devices and/or device components are described in U.S. Patent and/or Patent Application Nos. US2001/0031531, US2001/0034114, U.S. Pat. Nos. 408,677, 460,377, 1,164,987, 3,379,812, 3,829,536, 4,288,697, 4,356,400, 4,465,540, 4,748,328, 4,801,379, 4,812,236, 4,825,646, 4,856,043, 4,951,305, 5,002,889, 5,043,043, 5,147,761, 5,150,183, 5,190,637, 5,206,983, 5,252,881, 5,378,583, 5,447,068, 5,450,751, 5,459,320, 5,483,387, 5,551,904, 5,576,147, 5,606,589, 5,620,854, 5,638,212, 5,644,177, 5,681,661, 5,692,507, 5,702,384, 5,718,618, 5,721,687, 5,729,585, 5,763,318, 5,773,116, 5,778,468, 5,786,597, 5,795,748, 5,814,235, 5,814,807, 5,836,150, 5,849,229, 5,851,897, 5,924,277, 5,929,446, 5,932,940, 5,949,850, 5,955,801, 5,955,818, 5,962,949, 5,963,788, 5,985,204, 5,994,801, 5,994,816, 5,998,260, 6,004,500, 6,011,265, 6,014,419, 6,018,422, 6,018,680, 6,055,899, 6,068,684, 6,075,840, 6,084,626, 6,088,102, 6,124,663, 6,133,670, 6,134,294, 6,149,160, 6,152,181, 6,155,634, 6,175,615, 6,185,278, 6,188,743, 6,197,180, 6,210,644, 6,219,015, 6,226,120, 6,226,120, 6,242,163, 6,245,487, 6,245,849, 6,250,070, 6,252,938, 6,261,066, 6,276,313, 6,280,090, 6,299,300, 6,307,815, 6,310,419, 6,314,887, 6,318,069, 6,318,849, 6,324,748, 6,328,903, 6,333,584, 6,333,584, 6,336,318, 6,338,199, 6,338,249, 6,340,222, 6,344,392, 6,346,030, 6,350,983, 6,360,424, 6,363,712, 6,363,843, 6,367,911, 6,373,158, 6,375,871, 6,381,846, 6,382,588, 6,386,015, 6,387,713, 6,392,187, 6,392,313, 6,392,524, 6,393,685, 6,396,677, 6,397,677, 6,397,793, 6,398,490, 6,404,942, 6,408,884, 6,409,072, 6,410,213, 6,415,860, 6,416,168, 6,433,657, 6,440,284, 6,445,840, 6,447,727, 6,450,047, 6,453,083, 6,454,945, 6,458,263, 6,462,858, 6,467,138, 6,468,039, 6,471,471, and/or 6,480,320, each of which are incorporated by reference herein in their entirety. Microvalves can be enabling components of many microfluidic systems that can be used in many industry segments. Microvalves are generally classified as passive or active valves, but can share similar flow characteristics through varied orifice geometries. Diaphragm microvalves can be useful in many fluidic applications. FIG. 48A is a top view of an array 48010 of generic microdevices 48000. FIG. 48B is a cross section of a particular microdevice 48000 in this instance a diaphragm microvalve, taken along section lines 48-48 of FIG. 48A, the microvalve including diaphragm 48010 and valve seat 48020, as shown in the open position. FIG. 49 is a cross section of the diaphragm microvalve 48000, again taken along section lines 48-48 of FIG. 48A, the microvalve in the closed position. The flow rate through diaphragm microvalve 48000 can be controlled via the geometric design of the valve seat, which is often referred to as gap resistance. The physical characteristics of the valve seat, in combination with the diaphragm, can affect flow characteristics such as fluid pressure drop, inlet and outlet pressure, flow rate, and/or valve leakage. For example, the length, width, and/or height of the valve seat can be proportional to the pressure drop across the microvalve's diaphragm. Additionally, physical characteristics of the diaphragm can influence performance parameters such as fluid flow rate, which can increase significantly with a decrease in the Young's modulus of the diaphragm material. Valve leakage also can become optimized with a decrease in the Young's modulus of the diaphragm, which can enable higher deflection forces, further optimizing the valve's overall performance and/or lifetime. Typical microvalve features and specifications can include a valve seat: The valve seat, which is sometimes referred to as the valve chamber, can be defined by its size and the material from which it is made. Using an exemplary embodiment of a method, the dimensions of the chamber can be as small as about 10 microns by about 10 microns if square, about 10 microns in diameter if round, etc., with a depth in the range of about 5 microns to millimeters or greater. Thus, aspect ratios of 50, 100, or 200:1 can be achieved. The inner walls of the chamber can have additional micro features and/or surfaces which can influence various parameters, such as flow resistance, Reynolds number, mixing capability, heat exchange fouling factor, thermal and/or electrical conductivity, etc. The chamber material can be selected for application specific uses. As examples, a ceramic material can be used for high temperature gas flow, or a chemical resistant polymer can be used for chemical uses, and/or a bio-compatible polymer can be used for biological uses, to name a few. Valve chambers can be arrayed over an area to create multi-valve configurations. Each valve chamber can have complex inlet and outlet channels and/or ports to further optimize functionality and/or provide additional functionality. Typical microvalve features and specifications can also include a diaphragm: The diaphragm can be defined by its size, shape, thickness, durometer (Young's modulus), and/or the material from which it is made. Using an exemplary embodiment of a method, the dimensions of the diaphragm can be as small as about 25 microns by about 25 microns if square, about 25 microns in diameter if round, etc., with thickness of about 1 micron or greater. The surface of one side or both sides of the diaphragm could have micro features and/or surfaces to influence specific parameters, such as diaphragm deflection and/or flow characteristics. The diaphragm can be fabricated as a free form device that is attached to the valve in a secondary operation, and/or attached to a substrate. Diaphragms can be arrayed to accurately align to a matching array of valve chambers. Potential performance parameters can include valve seat and diaphragm material, diaphragm deflection distance, inlet pressure, flow, and/or lifetime. Micropumps FIGS. 50 and 51 are cross-sectional views of a particular micro-device 48000, in this case a typical simplified micropump, taken along section lines 48-48 of FIG. 48A. Micropumps can be an enabling component of many microfluidic systems that can be used in many industry segments. Reciprocating diaphragm pumps are a common pump type used in micro-fluidic systems. Micropump 50000 includes two microvalves 50010 and 50020, a pump cavity 50030, valve diaphragms 50040 and 50050, and actuator diaphragm 50060. At the initial state of pump 50000, the actuation is off, both inlet and outlet valves 50010 and 50020 are closed, and there is no fluid flow through pump 50000. Once actuator diaphragm 50060 is moved upwards, the cavity volume will be expanded causing the inside pressure to decrease, which opens inlet valve 50010 and allows the fluid to flow into and fill pump cavity 50030, as seen in FIG. 50. Then actuator diaphragm 50060 moves downward, shrinking pump cavity 50030, which increases the pressure inside cavity 50030. This pressure opens outlet valve 50020 and the fluid flows out of the pump cavity 50030 as seen in FIG. 51. By repeating the above steps, continuous fluid flow can be achieved. The actuator diaphragm can be driven using any of various drives, including pneumatic, hydraulic, mechanical, magnetic, electrical, and/or piezoelectrical, etc. drives. Typical microvalve features and specifications can include any of the following, each of which are similar to those features and specifications described herein under Microvalves: Valve seats Valve actuators (diaphragm) Cavity chamber Actuator diaphragm Potential performance parameters can include valve seat, chamber material, actuator diaphragm material, valve diaphragm material, deflection distance for actuator, deflection distance for valve diaphragms, inlet pressure, outlet pressure, chamber capacity, flow rate, actuator drive characteristics (pulse width, frequency, and/or power consumption, etc.), and/or lifetime. Microwells and Microwell Arrays Microwells can be an enabling component in many devices used for micro-electronics, micro-mechanics, micro-optics, and/or micro-fluidic systems. Precise arrays of micro-wells, potentially having hundreds to thousands of wells, can further advance functionality and process capabilities. Microwell technology can be applied to DNA micro-arrays, protein micro-arrays, drug delivery chips, microwell detectors, gas proportional counters, and/or arterial stents, etc. Fields of use can include drug discovery, genetics, proteomics, medical devices, x-ray crystallography, medical imaging, and/or bio-detection, to name a few. For example, using exemplary embodiments, microwells can be engineered in the third (Z) dimension to produce complex undercuts, pockets, and/or sub-cavities. Wells can also be arrayed over various size areas as redundant or non-redundant arrays. These features can include the dimensional accuracies and/or tolerances described earlier. Also, a range of surface treatments within the well structure are possible that can enhance the functionality of the well. Examples of Microwell Applications: DNA Microarrays: Scientists can rely on DNA microarrays for several purposes, including 1) to determine gene identification, presence, and/or sequence in genotype applications by comparing the DNA on a chip; 2) to assess expression and/or activity level of genes; and/or 3) to measure levels of proteins in protein based arrays, which can be similar to DNA arrays. DNA microarrays can track tens of thousands of reactions in parallel on a single chip or array. Such tracking is possible because each probe (a gene or shorter sequence of code) can be deposited in an assigned position within the cell array. A DNA solution, representing a DNA sample that has been chopped into constituent sequences of code, can be poured over the entire array (DNA or RNA). If any sequence of the sample matches a sequence of any probe, the two will bind, and non-binding sequences can be washed away. Because each sequence in the sample or each probe can be tagged or labeled with a fluorescent, any bound sequences will remain in the cell array and can be detected by a scanner. Once an array has been scanned, a computer program can convert the raw data into a color-coded readout. Protein Microarrays: The design of a protein array is similar to that of a DNA chip. Hundreds to thousand of fluorescently labeled proteins can be placed in specific wells on a chip. The proteins can be deposited on the array via a pin or array of pins that are designed to draw fluidic material from a well and deposit it on the inside of the well of the array. The position and configuration of the cells on the array, the pins, and the wells are located with the accuracy needed to use high-speed pick-and-place robotics to move and align the chip over the fluidic wells. A blood sample is applied to the loaded array and scanned for bio-fluorescent reactions using a scanner. Certain embodiments of the invention enable DNA or Protein microarrays having a potentially large number of complex 3-dimensional wells to be fabricated using any of a range of materials. For example, structures can be fabricated that combine two or more types of material in a microwell or array. Additional functionality and enhancements can be designed into a chip having an array of microwells. Wells can be produced having cavities capable of capturing accurate amounts of fluids and/or high surface-to-volume ratios. Entrance and/or exit configurations can enhance fluid deposition and/or provide visual enhancements to scanners when detecting fluorescence reactions. Very precise well locations can enable the use of pick and place robotics when translating chips over arrays of fluidic wells. Certain embodiments of the invention can include highly engineered pins and/or pin arrays that can be accurately co-aligned to well arrays on chips and/or can have features capable of efficiently capturing and/or depositing fluids in the wells. Arterial Stents: Stents are small slotted cylindrical metal tubes that can be implanted by surgeons to prevent arterial walls from collapsing after surgery. Typical stents have diameters in the 2 to 4 millimeter range so as to fit inside an artery. After insertion of a stent, a large number of patients experience restenosis—a narrowing of the artery—because of the build-up of excess cells around the stent as part of the healing process. To minimize restenosis, techniques are emerging involving the use of radioactive elements or controlled-release chemicals that can be contained within the inner or outer walls of the stent. Certain embodiments of the invention can provide complex 3-dimensional features that can be designed and fabricated into the inside, outside, and/or through surfaces of tubing or other generally cylindrical and/or contoured surfaces. Examples 4 and 5 teach such a fabrication technique for a 3 mm tube. Certain embodiments of the invention can allow the manufacture of complex 2-dimensional and/or 3-dimensional features through the wall of a stent. Micro surfaces and features can also be incorporated into the stent design. For example, microwells could be used to contain pharmaceutical materials. The wells could be arrayed in redundant configurations or otherwise. The stent features do not have to be machined into the stent surface one at a time, but can be applied essentially simultaneously. From a quality control perspective, features formed individually typically must be 100% inspected, whereas features produced in a batch typically do not. Furthermore, a variety of application specific materials (e.g., radio-opaque, biocompatible, biosorbable, biodissolvable, shape-memory) can be employed. Microwell Detectors: Microwells and microwell arrays can be used in gas proportional counters of various kinds, such as for example, in x-ray crystallography, in certain astrophysical applications, and/or in medical imaging. One form of microwell detector consists of a cylindrical hole formed in a dielectric material and having a cathode surrounding the top opening and anode at the bottom of the well. Other forms can employ a point or pin anode centered in the well. The microwell detector can be filled with a gas such as Xenon and a voltage can be applied between the cathode and anode to create a relatively strong electric field. Because of the electric field, each x-ray striking an atom of the gas can initiate a chain reaction resulting in an “avalanche” of hundreds or thousands of electrons, thereby producing a signal that can be detected. This is known as a gas electron multiplier. Individual microwell detectors may be used to detect the presence and energy level of x-rays, and if arrays of microwell detectors are employed, an image of the x-ray source can be formed. Such arrays can be configured as 2-dimensional and/or 3-dimensional arrays. Certain embodiments of the invention can enable arrays of complex 3-dimensional wells to be fabricated and bonded or coupled to other structures such as a cathode material and anode material. It is also possible to alter the surface condition of the vertical walls of the wells, which can enhance the laminar flow of electrons in the well. A number of possible materials can be used to best meet the needs of a particular application, enhancing parameters such as conductivity, die-electrical constant, and/or density. Certain embodiments of the invention can further enable the hybridizing of micro-electronics to a well array, in particular because of accurate co-alignment between the micro-electronic feature(s), and/or the structural elements of the well. Typical Microwell Features, Specifications and Potential Performance Parameters: FIG. 52 is a top view of an exemplary microwell array 52000, showing microwells 52010, and the X- and Y-axes. Array 52000 is shown as rectangle, but could be produced as a square, circle, or any other shape. Either of the array's dimensions as measured along the X- or Y-axes can range from 20 microns to 90 centimeters. Microwells 52010 are shown having circular perimeters, but could also be squares, rectangles, or any other shape. Array 52000 is shown having a redundant array of wells 52010, but could be produced to have non-redundant wells. The positional accuracy of wells 52010 can be accurate to the specifications described herein for producing lithographic masks. Wells can range in size from 0.5 microns to millimeters, with cross-sectional configurations as described herein. Using certain embodiments of a method, certain materials can be used to produce microwell arrays for specific uses. For example, a ceramic material can be used for high-temperature gas flow, a chemical resistant polymer can be used for chemical uses, and/or a bio-compatible polymer can be used for biological uses, to name a few. Specialty composite materials can enhance application specific functionality by being conductive, magnetic, flexible, hydrophilic, hydrophobic, piezoelectric, to name a few. Using an embodiment of a method, microwells with certain 3-dimensional cross-sectional shapes can be produced. FIG. 52 is a top view of an exemplary array 52000 of microwells 52010. FIG. 53 is a cross-sectional view, taken at section lines 52-52 of FIG. 52, of an exemplary microwell 53000 having an entrance 53010. Entrance 53010 is shown having a tapered angle, which could be angled from 0 degrees to nearly 180 degrees. Entrance 53010 is also shown having a different surface than well area 53020. Well area 53020 can be square, round, rectangular, or any other shape. Well area 53020 can range in size from 0.5 microns to millimeters in width and can be dimensionally controlled in the Z-axis to have aspect ratios of from about 50:1 to about 100:1. As shown in FIG. 53, microwell 53000 defines microwell surfaces 53050, 53060, 53070, 53080, 53090, 53100, 53110. As also shown in FIG. 53, a cross-sectional surface 53030 is defined that intersects microwell surfaces 53050, 53060, 53070, 53080, 53090, 53100, 53110. As further shown in FIG. 53, a central area and/or layer-less volume 53040 of cross-sectional surface 53030 comprises a majority of cross-sectional surface 53030, yet does not include any of microwell surfaces 53050, 53060, 53070, 53080, 53090, 53100, 53110, which define a periphery 53120 of central area and/or layer-less volume 53040 of microwell 53000. FIG. 54 is a cross-sectional view, taken at section lines 52-52 of FIG. 52, of an alternative exemplary microwell 54000 that defines an entrance 54010, a well 54020, and an exit 54030. Microwell 54000 can be used in applications that require fluids that are conveyed from below or above the entrance 54010 and/or exit 54030, and deposited in well 54020. Using an embodiment of a method, microwell 54000 can be produced so that well 54020 is hydrophilic and entrance 54010 and exit 54030 are hydrophobic to, for example, enable the deposition of fluid into well 54020, and discourage the fluid deposition, retention, and/or accumulation on entrance 54010, on exit 54030, and/or on the chip's surface. For uses where microelectronic controls or chips are employed, the material surrounding and/or defining entrance 54010 and/or 54030 can be conductive or non-conductive, as required. Well 54020 can be dimensioned to accurately contain a pre-determined amount of fluid. The shape and size of corner feature 54040 can be defined to encourage the discharge of a fluid material from a fluidic channel on a pin, when a pin is produced using any of certain embodiments of the invention. For example, pins can be produced having fluidic channels or undercuts that are positioned radially at the end of the pin. The undercuts can serve as reservoirs that increase surface area-to-volume ratios and/or hold accurate amounts of fluids. If the undercuts are designed to be relatively flexible and larger than the opening dimension at feature 54040, fluid can be squeezed from the reservoir as the fluid passes by corner feature 54040. Entrance 54010 can have an angle that promotes the visibility of a material, such as a fluid, in well 54020. The material surrounding and/or defining well 54020 can be fabricated to have micro-surface features to increase the well's surface area-to-volume ratio. FIG. 55 is a top view of an exemplary microwell 55000 showing a well area 55010 and sub-cavities 55020. FIG. 56 is a cross-sectional view, taken at section lines 56-56 of FIG. 55, of microwell 55000 showing well 55010 and sub-cavities 55020. Well 55010 can extend through the material that defines it, as shown in FIG. 56, or can be a closed well having a solid floor. Sub-cavities 55020 can be incorporated within a well to, for example, increase an area of the surface(s) bordering the well, a volume, and/or surface area-to-volume ratio of the well. Sub-cavities 55020 can be continuous rings as shown in FIG. 55. Alternatively, sub-cavities 55020 can be discrete pockets forming sub-wells within well 55010. Sub-cavities 55020 can be positioned on a horizontal floor or subfloor of well 55010 as shown in FIG. 55, on the vertical walls of well 55010, and/or on another surface. Sub-cavities 55020 can have circular, square, rectangular, and/or any of a variety of other cross-sectional shapes. Sub-cavities 55020 can also be positioned to provide an enhanced visual perspective of a deposited material from which could be angled from 0 degrees to nearly 180 degrees, such as an approximately perpendicular angle, so as to enhance scanning performance or resolution. Filtration Filtration can be an important element in many industries including medical products, food and beverage, pharmaceutical and biological, dairy, waste water treatment, chemical processing, textile, and/or water treatment, to name a few. Filters are generally classified in terms of the particle size that they can separate. Micro-filtration generally refers to separation of particles in the range of approximately 0.01 microns through 20 microns. Separation of larger particles than approximately 10-20 microns is typically referred to as particle separation. There are two common forms of filtration, cross-flow and dead-end. In cross-flow separation, a fluid stream runs parallel to a membrane of a filter while in dead-end separation, the filter is perpendicular to the fluid flow. There are a very large number of different shapes, sizes, and materials used for filtration depending on the particular application. Certain embodiments of the invention can be filters suitable for micro-filtration and/or particle filtration applications. Certain embodiments of the invention allow fabrication of complex 2-dimensional and/or 3-dimensional filters offering redundant or non-redundant pore size, shape, and/or configuration. For example, a circular filter can have an array of redundant generally circular through-features, each through-feature having a diameter slightly smaller than a target particle size. Moreover, the through-feature can have a tapered, countersunk, and/or undercut entrance, thereby better trapping any target particle that encounters the through-feature. Further, the cylindrical walls defined by the through-feature can have channels defined therein that are designed to allow a continued and/or predetermined amount of fluid flow around a particle once the particle encounters the through-feature. The fluid flow around the particle can create eddys vortices, and/or other flow patterns that better trap the particle against the filter. Certain embodiments of the filter can have features that allow the capture of particles of various sizes at various levels of the filter. For example, an outer layer of the filter can capture larger particles, a middle layer can capture mid-sized particles, and a final layer can capture smaller particles. There are numerous techniques for accomplishing such particle segregation, including providing through-features having tapered, stepped, and/or diminishing cross-sectional areas. In certain embodiments, the filter can include means for detecting a pressure drop across the filter, and/or across any particular area, layer, and/or level of the filter. For example, in a filter designed to filter a gas such as air, micro pitot tubes can be fabricated into each layer of the filter (or into selected layers of the filter). Such pressure measurement devices can be used to determine the pressure drop across each layer, to detect the level of “clogging” of that layer, and/or to determine what size and/or concentration of particles are entrapped in the filter. Further, certain embodiments of the invention allow for fabrication of filters in a wide range of materials including metals, polymers, plastics, ceramics, and/or composites thereof. In biomedical applications, for instance, a biocompatible material can be used that will allow filtration of blood or other body fluids. Using certain embodiments of the invention, filtration schemes can be engineered as planar or non-planar configurations. Sorting Sorting can be considered a special type of filtration in which particles, solids, and/or solids are separated by size. In biomedical applications for example, it may be desirable to sort blood or other types of cells by size and deliver different sizes to different locations. Certain embodiments of the invention can enable the fabrication of complex 3-dimensional structures that allow cells to be sorted by size (potentially in a manner similar to that discussed herein for filters) and/or for cells of different sizes to be delivered through different size micro-channels or between complex 3-dimensional structures. Structures can be material specific and on planar or non-planar surfaces. Membranes Membranes can offer filtration via pore sizes ranging from nanometers to a few microns in size. Membrane filtration can be used for particles in the ionic and molecular range, such as for reverse osmosis processes to desalinate water. Membranes are generally fabricated of polymers, metals, or ceramics. Micro-filtration membranes can be divided into two broad types based on their pore structure. Membranes having capillary-type pores are called screen membranes, and those having so-called tortuous-type pores are called depth membranes. Screen membranes can have nearly perfectly round pores that can be dispersed randomly over the outer surface of the membrane. Screen membranes are generally fabricated using a nuclear track and etch process. Depth membranes offer a relatively rough surface where there appear to be openings larger than the rated size pore, however, the fluid must follow a random tortuous path deeper into the membrane to achieve their pore-size rating. Depth membranes can be fabricated of silver, various cellulosic compounds, nylon, and/or polymeric compounds. Certain embodiments of the invention enable fabrication of membranes having complex 3-dimensional shapes, sizes, and/or configurations made of polymers, plastics, metals, and/or ceramics, etc. Furthermore, such membranes can embody redundant or non-redundant pores, and can be fabricated to be flexible, rigid, and/or non-planar depending upon the material and/or application requirements. Heaters Certain exemplary embodiments can provide heaters and/or components thereof, potentially having high resolution and/or high aspect ratios. For example, an exemplary embodiment can provide a resistive heater having numerous wire, strip, and/or coil, etc. elements having substantially large length and/or width dimensions with respect to their thickness dimensions. Certain exemplary embodiments can provide heaters that utilize a Seebeck effect for heating. Heat Exchangers Certain exemplary embodiments can provide heat exchangers and/or components thereof, potentially having high resolution and/or high aspect ratios. For example, an exemplary embodiment can provide a heat exchanger having numerous “fins” or other surfaces having substantially large length and/or width dimensions with respect to their thickness dimensions, thereby providing relatively large surface area to volume ratios to facilitate heat transfer. Such heat exchangers can be used for heating and/or cooling of a target fluid and/or material. Also, exemplary embodiments can provide thin-walled tubular heat exchangers, having tubes that potentially incorporate “fins” and/or other heat transfer surfaces. Exemplary embodiments of fins and the like can have secondary features that can be useful for further increasing surface area, manipulating and/or optimizing flow, controlling fouling, etc. Certain exemplary embodiments can provide heat exchangers that utilize a Peltier, Seebeck, and/or Joule effect for cooling and/or heating. Mass Exchangers Certain exemplary embodiments can provide mass exchangers and/or components thereof, potentially having high resolution and/or high aspect ratios. For example, an exemplary embodiment can provide a mass exchanger having numerous “fins” or other surfaces capable of releasing an impregnated and/or bound material, and/or having receptors for receiving a target material. Each such fin can have substantially large length and/or width dimensions with respect to their thickness dimensions, thereby providing relatively large surface area to volume ratios to facilitate mass transfer. Another exemplary embodiment can provide a mass exchanger, such as pieces of packing, each having numerous surfaces and having a large surface area to volume ratio. Another exemplary embodiment can provide a mass exchanger, such as a static mixer having numerous fluid dividing/mixing surfaces. Exemplary embodiments of fins and the like can have secondary features that can be useful for further increasing surface area, manipulating and/or optimizing mass transfer, etc. Surface Reactors Certain exemplary embodiments can provide surface reactors and/or components thereof, potentially having high resolution and/or high aspect ratios. For example, an exemplary embodiment can provide a surface reactor having numerous “fins” or other surfaces comprising and/or bound to a material capable of reacting with a target material, and/or catalyzing such a reaction. Each such fin can have substantially large length and/or width dimensions with respect to their thickness dimensions, thereby providing relatively large surface area to volume ratios to facilitate higher reaction rates. Exemplary embodiments of fins and the like can have secondary features that can be useful for further increasing surface area, manipulating and/or optimizing reaction rates, controlling heating, cooling, mixing, and/or flow, etc. Fuel Cells Certain exemplary embodiments can provide a fuel cell having one or more discrete and/or integrated components such as a channel, manifold, separator, pump, valve, filter, heater, cooler, heat exchanger, mass exchanger, and/or surface reactor, etc., of any size and/or configuration. Such a fuel cell can be useful as a power cell, battery, charger, etc. For example, an embodiment of the invention can provide a fuel cell having a solid electrolyte disposed between an oxygen electrode and a fuel electrode, and one or more separators can contact the surface of one of the electrodes opposite of the electrolyte. At least one electrode of the cell can define a micro-channel pattern, wherein the micro-channel cross-section can be varied, such that reactant gas flowing through the micro channels can achieve tailored local flow, pressure, and/or velocity distributions. An exemplary embodiment of the invention can provide a proton exchange diffusion membrane fuel cell having a membrane and/or channels. An exemplary embodiment of the invention can provide a fluid fuel cell, such as a hydrogen fuel cell, proton exchange member, and/or a direct methanol fuel cell, utilizing one or more fluid mixers, mixing chambers, pumps, and/or recirculators. Turbomachinery and Machinery Certain exemplary embodiments can provide turbomachinery devices and/or components thereof, potentially having high resolution and/or high aspect ratios. For example, an exemplary embodiment can provide a microturbine having an impeller, rotor, blades, stages, seals, and/or nozzles, etc., any of which can high a high aspect ratio be formed from a material having a high strength, and/or be formed from a material having desired thermal performance capabilities, such as a ceramic. The microturbine can that can be coupled to a microgenerator for generating electrical power and/or can be used for generating thrust. Another exemplary embodiment can provide a microcombustion engine having free pistons magnetically coupled to electromagnets for control and power transfer. Ion Beam Technologies Certain exemplary embodiments can provide ion beam devices and/or components thereof, potentially having high resolution and/or high aspect ratios. For example, space propulsion, surface cleaning, ion implantation, and high energy accelerators use two or three closely spaced multiple-aperture electrodes to extractions from a source and eject them in a collimated beam. The electrodes are called “grids” because they are perforated with a large number of small holes in a regular array. A series of grids constitute an “ion optics” electrostatic ion accelerator and focusing system. Ion Thrusters On-board propulsion systems can be used to realize a variety of spacecraft maneuvers. In satellites, for example, these maneuvers include the processes of orbit raising (e.g., raising from a low Earth orbit to a geostationary orbit), stationkeeping (e.g., correcting the inclination, drift and eccentricity of a satellite's orbit) and attitude control (e.g., correcting attitude errors about a satellite's roll, pitch and yaw axes). Certain exemplary embodiments can provide propulsion and/or micropropulsion devices and/or components potentially having high resolution and/or high aspect ratios. For example, an exemplary embodiment can provide an ion thruster, microthruster, Kaufman-type ion engine, and/or electric rocket engine that can be useful for maintaining the orbit and/or relative position of a geosynchronous satellite. Such a device can utilize an orifice, orifice array, and/or grid. In certain embodiments, an ion thruster grid can have a spherically-formed and/or domed screen pattern with, for example, a high resolution and/or high aspect ratio. Ion beam sources designed for spacecraft propulsion, that is, ion thrusters, typically are preferred to have long lifetimes (10,000 hours or more), be efficient, and be lightweight. Ion thrusters have been successfully tested in space, and show promise for significant savings in propellant because of their high specific impulse (an order of magnitude higher than that of chemical rocket engines). They have yet to achieve any significant space use, however, because of lifetime limitations resulting from grid erosion and performance constraints resulting from thermal-mechanical design considerations, particularly the spacing of metallic grids, including molybdenum. In an ion thruster, a plasma is created and confined within the body of the thruster. Ions from the plasma are electrostatically accelerated rearwardly by an ion-optics system. The reaction with the spacecraft drives it forwardly, in the opposite direction. The force produced by the ion thruster is relatively small. The ion thruster is therefore operated for a relatively long period of time to impart the required momentum to the heavy spacecraft. For some missions the ion thruster must be operable and reliable for thousands of hours of operation, and with multiple starts and stops. The ion-optics system can include grids to which appropriate voltages are applied in order to accelerate the ions rearwardly. In a typical electron bombardment ion thruster, a cathode produces electrons that strike neutral gas atoms introduced through a propellant feed line. The electrons ionize the gas propellant and produce a diffuse plasma. In a radio frequency ion thruster, the propellant is ionized electromagnetically by an external coil, and there is no cathode. In both cases, an anode associated with the plasma raises its positive potential. To maintain the positive potential of the anode, a power supply pumps to ground potential some of the electrons that the anode collects from the plasma. These electrons are ejected into space by a neutralizer to neutralize the ion beam. Magnets act to inhibit electrons and ions from leaving the plasma. Ions drift toward the ion optics, and enter the holes in a screen grid. A voltage difference between the screen grid and an accelerator grid accelerates the ions, thereby creating thrust. The screen grid is at the plasma potential, and the accelerator grid is held at a negative potential to prevent downstream electrons from entering the thruster. Optionally, the optics can include a decelerator grid located slightly downstream of the accelerator grid and held at ground potential or at a lesser negative potential than the accelerator grid to improve beam focusing and reduce ion impingement on the negative accelerator grid. The grids can be in a facing orientation to each other, spaced apart by relatively small clearances such as about 0.035 inches at room temperature. The grids can include aligned apertures therethrough. Some of the ions accelerated by the applied voltages can pass through the apertures, providing the propulsion. Others of the ions can impact the grids, heating them and etching away material from the grids by physical sputtering. The heating and electrostatic forces on the grids can combine to cause substantial mechanical forces at elevated temperature on the grids, which can distort the grids unevenly. The uneven distortion of the grids can cause adjacent grids to physically approach each other, rendering them less efficient and prone to shorting against each other. These effects can be taken into account in the design of the grids and the operation of the ion thruster, so that the thruster can remain functional for the required extended lifetimes. However, limitations may be placed on the operation of the ion thruster because of grid distortion, such as a relatively slow ramp-up in power during startup and operation, so that the adjacent grids do not expand so differently that they come into contact. A factor that can affect the efficiency and/or the weight of ion thrusters is how closely and precisely the grids can be positioned while maintaining relative uniformity in the grid-to-grid spacing at high operating temperatures or in conditions where the spatial temperature is nonuniform and thermal distortion can occur because of temperature gradients. Grids are frequently made of molybdenum formed into a domed shape. The molybdenum can resist material removal by physical sputtering. The domed shape can establish the direction of change due to thermal expansion and/or can aid in preventing a too-close approach of the adjacent grids as a result of differences in temperatures of the adjacent grids. Exemplary embodiments of ion thruster grids, such as those formed according to an exemplary embodiment of a method, can be precisely formed into matching shapes, which can account for deformation that can occur due to thermal expansion when a thruster heats in operation. Changes in the actual spacing and the uniformity of spacing over the grid surfaces between the grids can potentially be predicted and/or controlled. Exemplary embodiments of ion thruster grids, such as those formed according to an exemplary embodiment of a method, can be formed of any moldable material, include tungsten, molybdenum, ceramics, graphite, etc. Exemplary embodiments of ion thruster grids, such as those formed according to an exemplary embodiment of a method, can have relatively long lifetimes, allow for precise alignment and/or spacing between grids, and/or allow for precise alignment and/or spacing of grid openings. Ion Beam Grids Ion beams can be used in the production of components in the micro-electronics industry and magnetic thin film devices in the storage media industry. Typically, an ion beam, such as an argon ion beam, has a large area, a high current and an energy of between 100 eV and 2 keV. The beam can be used in a number of ways to modify the surface of a substrate, for example by sputter deposition, sputter etching, milling, or implantation. In a typical ion beam source (or ion gun) a plasma is produced by admitting a gas or vapor to a low pressure discharge chamber containing a heated cathode and an anode which serves to remove electrons from the plasma and to give a surplus of positively charged ions which pass through a screen grid or grids into a target chamber which is pumped to a lower pressure than the discharge chamber. Ions are formed in the discharge chamber by electron impact ionization and move within the body of the ion gun by random thermal motion. The plasma will thus exhibit positive plasma potential which is higher than the potential of any surface with which it comes into contact. Various arrangements of grids can be used, the potentials of which are individually controlled. In a multigrid system, the first grid encountered by the ions is usually positively biased whilst the second grid is negatively biased. A further grid may be used to decelerate the ions emerging from the ion source so as to provide a collimated beam of ions having more or less uniform energy. For ion sputtering a target is placed in the target chamber where this can be struck by the beam of ions, usually at an oblique angle, and the substrate on to which material is to be sputtered is placed in a position where sputtered material can impinge on it. When sputter etching, milling or implantation is to be practiced the substrate is placed in the path of the ion beam. Hence, in a typical ion gun an ion arriving at a multiaperture extraction grid assembly first meets a positively biased grid. Associated with the grid is a plasma sheath. Across this sheath is dropped the potential difference between the plasma and the grid. This accelerating potential will attract ions in the sheath region to the first grid. Any ion moving through an aperture in this first grid, and entering the space between the first, positively biased grid, and the second, negatively biased, grid is strongly accelerated in an intense electrical field. As the ion passes through the aperture in the second grid and is in flight to the grounded target it is moving through a decelerating field. The ion then arrives at an grounded target with an energy equal to the potential of the first, positive, grid plus the sheath potential. Exemplary embodiments of ion beam grids, such as those formed according to an exemplary embodiment of a method, can have relatively long lifetimes, allow for precise alignment and/or spacing between grids, and/or allow for precise alignment and/or spacing of grid openings. Such grids can be planar and/or non-planar, can have redundant and/or non-redundant grid openings, can have anisotropic and/or isotropic grid openings, and/or can be constructed of nearly any moldable material, including composite materials. Microfluidics Certain exemplary embodiments can provide fluidic and/or microfluidic devices and/or components thereof, potentially having high resolution and/or high aspect ratios. For example, an exemplary embodiment can provide a pressure regulator and/or controller that utilizes a valve, orifice, and/or nozzle having a high aspect ratio and formed using an embodiment. Actuators Certain exemplary embodiments can provide actuators and/or components thereof, potentially having high resolution and/or high aspect ratios. For example, an exemplary embodiment can provide a valve actuator having an electromagnetic, magnetic, piezoelectric, electrostatic, bimetallic, and/or shape memory component formed using an embodiment and having a high aspect ratio. Attenuators Certain exemplary embodiments can provide attenuators and/or components thereof, potentially having high resolution and/or high aspect ratios. For example, an exemplary embodiment can provide an acoustical attenuator having numerous microbaffles for absorbing undesired sound waves, such as sound waves of a particular frequency range. Such baffles can be textured, dimensioned, and/or shaped to enhance their performance capabilities. Likewise, attenuators can be provided for attenuating flow, electromagnetic radiation (e.g., light, electrical current, x-rays, etc.), etc. Motion Devices Certain exemplary embodiments can provide gyroscopes, accelerometers, tilt detectors, etc., and/or components thereof, potentially having high resolution and/or high aspect ratios. Such devices can be useful for navigation, stabilization, airbag crash systems, vibration detection, earthquake detection, anti-theft and/or security systems, active suspensions, automated braking systems, vehicle rollover prevention systems, headlight leveling systems, seatbelt tensioners, motor controllers, pedometers, stereo speakers, computer peripherals, flight simulators, sports training, robots, machine health monitors, etc. For example, an exemplary embodiment can provide an accelerometer having a cantilevered inertial mass coupled to at least one electrical element, such as a capacitive sensor that is adapted to generate a signal upon sufficient change in acceleration (movement) of the cantilevered inertial mass. In certain embodiments, the mass and electrical element can be substantially co-planar. In certain embodiments, the mass can have a substantial aspect ratio, and electrical elements can be provided in orthogonal and/or multiple planes, so that changes in orientation, displacement, and/or motion (e.g., linear, curvilinear, and/or rotational velocity, acceleration, jerk, pulse, etc.) in any direction can be sensed, measured, and/or analyzed. Mirrors Certain exemplary embodiments can provide a mirror and/or components thereof, potentially having high resolution and/or high aspect ratios. Such a mirror can be a component of an optical device and/or an opto-mechanical device, such as an opto-mechanical switching cell and/or a laser scanner, such as is used in a bar-code scanner or a holographic data storage system. Exemplary arrays of mirrors can be redundant and/or non-redundant. Exemplary mirrors can be planar and/or non-planar. Exemplary mirrors can have a reflectivity that varies in any fashion (e.g., linearly, non-linearly, polarly, radially, controllably, periodically, thermally, etc.) across a surface of the mirror. Grating Light Valves Grating light valves can resemble small reflectors/diffractors, each comprising several structures that resemble ribbon-like beams supported on each end, which can electrostatically actuated upwards or downwards (typically a fraction of the wavelength of visible light). The ribbon-like structures can be arranged to form an element that variably reflects or diffracts light, in either a continuous or discrete (on-off) manner. Grating light valves can have utility in optical attenuators, switches, relays, direct-to-plate printers, HDTV monitors, electronic cinema projectors, and/or commercial flight simulator displays. Exemplary embodiments of grating light valves, such as those formed according to an exemplary embodiment of a method, can include redundant and/or non-redundant arrays of reflector and/or diffractor elements. Each such element can be planar and/or non-planar, and can include an actuator, such as those used in optical switching arrays. Fuses Certain exemplary embodiments can provide methods for fabricating a fuse and/or components thereof, potentially having a high-resolution and/or high-aspect ratio, which can be used for triggering and/or disconnecting the flow of fluid and/or current. For example, fluid fuse comprising a low melting (fusible) alloy can be useful for triggering and/or actuating a sprinkler head in a fire protection system. As another example, an electrical fuse comprising an electrically fusible alloy can be useful for disconnecting a current flow to an electronic and/or electrical device. Signal Detecting Collimators and Devices Certain exemplary embodiments can provide methods for fabricating a grid structure and/or components thereof, potentially having a high-resolution and/or high-aspect ratio, which can be used for signal detection collimators. Such devices can be used in the field of acoustics to, for example, enhance acoustical signal detection and/or analysis, by for example, reflecting, dispersing, filtering, and/or absorbing sound waves. Such devices can be used in the field of imaging to, for example, enhance image contrast and quality by refracting, diffracting, reflecting, dispersing, filtering, and/or absorbing scattered radiation (sometimes referred to as “off-axis” radiation and/or “secondary” radiation). In this context, “radiation” means electromagnetic radiation, and can include radio, television, microwave, infrared, visible light, ultraviolet, alpha-rays, beta-rays, gamma rays, and/or x-rays, etc., and can even include high energy particles, ion beams, etc. Moreover, much of the following discussion regarding radiation is analogous to acoustical energy, vibration, and/or other forms of energy that have a varying and/or frequency component (e.g., a time-varying component, a spatially-varying component, a dimensionally-varying component, etc.). As an example, certain exemplary embodiments can provide a collimator having optical properties, such as cell walls capable of absorbing certain wavelengths, that can be used as a notch filter. Other such collimators can have certain cells filled with a material that has certain refractive properties, thereby providing a lens effect with those cells. Other such collimators can have reflective and/or curved cell walls thereby serving as a reflector and/or wave guide. Certain exemplary embodiments can provide a collimator having at least one curved face, and possibly having both faces curved, such that each cell is “pointed” in a different direction. In various embodiments, the curve can be circular, elliptical, curvilinear, cylindrical, and/or spherical, etc., and can be concave and/or convex. Such collimators can be useful for detecting a direction of a radiation source with respect to the collimator and/or the imaging machine comprising the collimator, particularly when the machine also comprises a pixilated detector array and an image processing capability. Thus, in certain embodiments, such as those in which the “outer” face of the collimator is convex, such collimators can function as a form of “wide-angle lens” for whatever type of radiation the collimator is designed to pass. Moreover, by analyzing the time variance of the detected radiation, such machines can determine changes in direction or intensity of the emitted and/or incoming radiation. Further, by analyzing the frequency components of the detected radiation, such machines can determine, perhaps with a high degree of precision, the nature of the radiation source. As an example, an imaging machine comprising such a curved collimator could be deployed at a location having a relatively wide view of a stadium parking lot. The collimator can direct light originating from any particular location in the view to a corresponding detector element. By virtue of its power, time, and/or frequency analysis capability, such an imaging machine could detect the source of a bright and rapid flash of infrared and visible light and/or other forms of radiation, such as occurs when a handgun is fired. The imaging machine could then alert authorities to the location of the fired handgun, and could trigger a video camera to turn to and zoom in on the location to capture a visible image of the scene, potentially capturing images of the faces of witnesses and/or perpetrators, license plate numbers, etc. As another example, an imaging machine comprising such a curved collimator could be deployed at a location having a relatively wide view of a port, shipping channel, runway, rail yard, border crossing, roadway, warehouse, parking lot, etc. Once deployed, the imaging machine can detect, for example, gamma radiation, such as emitted from a radioactive source, such as a radioactive medical waste, nuclear fuel, and/or a radiation bomb. Upon detection, the imaging machine could alert authorities to the approach, movement, and/or specific location of the radioactive source. As yet another example, an imaging machine comprising a concave collimator could be deployed at a conveyor and opposite a radiation source, such as is used for scanning passenger bags in commercial airports, train stations, bus depots, etc. In an environment with many such conveyors each having a radiation source, such a collimator can isolate radiation to that coming from its corresponding radiation source. FIG. 57 illustrates an exemplary embodiment of a microstructure derived from a finite element analysis (FEA) and formed via an exemplary method described herein. FIG. 58 is a perspective view of an exemplary embodiment of opposing interlocking microstructures formed via an exemplary method described herein. More specifically, FIGS. 57-58 show microstructures derived from a finite element analysis and extracted from a thick film plastic sheet. Note that a mold from which each microstructure is derived can be formed from a plurality of lithographically-derived, micro-machined metallic foil layers (11 such layers are shown in FIG. 57), which have been precisely aligned and stack laminated into a monolithic solid. FIG. 59 is a perspective view of an exemplary embodiment of a lattice microstructure formed via an exemplary method described herein. More specifically, FIG. 59 shows an LAMMS array of microstructures derived from a finite element analysis and extracted from an intermediate thin metal foil. FIG. 60 is a perspective view of an exemplary embodiment of a composite microstructure formed via an exemplary method described herein. More specifically, FIG. 60 shows a combination of the microstructures of FIG. 58 and FIG. 59. FIG. 61 is a flowchart of an exemplary embodiment of a basic sequence of an exemplary method described herein. More specifically, FIG. 61 is a flowchart of an exemplary manufacturing process for making certain exemplary microstructures and/or LAMMS, such as the microstructures of FIG. 60. FIG. 62 is a block diagram of an exemplary embodiment of a basic sequence of an exemplary method described herein. More specifically, FIG. 62 is a schematic of an exemplary manufacturing process for making certain exemplary microstructures and/or LAMMS, such as the microstructures of FIG. 60. FIG. 63 is a perspective view of an exemplary embodiment of a simplified microstructure formed via an exemplary method described herein. More specifically, FIG. 63 illustrates an exemplary simplified LAMMS showing an array of microstructures such as those shown in FIG. 60, which can be used to form an aeroframe skin panel. The following examples have been selected to illustrate several potential attributes of the LAMMS™ process. FIG. 64 is a perspective view of an exemplary embodiment of a macro-scale surface comprising a plurality of microstructures, the surface and microstructures formed via an exemplary method described herein. More specifically, FIG. 64 (example 1) demonstrates the use of LAMMS™ to array precisely angled micro-scale features across a macro-scale surface. FIG. 65 is a photomicrograph of exemplary columnar microstructures formed via an exemplary method described herein. FIG. 66 is a photomicrograph of exemplary cast microstructures formed via an exemplary method described herein. More specifically, FIGS. 65 and 66 (examples 2 and 3) demonstrate production of more complex 3D features. For demonstration purposes, each example has been produced in a single-ply configuration using a casting process. In the first example, a precision TLM™ mold was fabricated having 131,589 cylindrical shape cavities arrayed over a 45 centimeter diameter surface. The resulting cavities are 0.950 millimeters in diameter, have a depth of 3.25 millimeters, and are arrayed in staggered rows and columns to maximize the pattern density. The pitch frequency of the cavities is 1.00 millimeter. The arrayed pattern is comprised of four identical quadrants located around a central x, y datum. The cavity located at the center of the array is perpendicular to the mold surface at an angle of 90 degrees (datum cavity). The remaining cavities in each quadrant of the mold are uniquely angled relative to the mold surface. A cumulative angle of 0.01196 degrees was applied to each cavity position within each quadrant (1.00 millimeter pitch) resulting in a focused cavity array with each cavity pointing precisely at a predetermined focal point. The focal point of the array was centered on the datum cavity at a distance of 5 meters. Using a vacuum assisted casting process, a LAMMS™ device was derived from the TLM™ mold using a high strength poly-urethane resin. The cast resin part and the TLM™ mold were dimensionally characterized and compared for accuracy. The measurements were made using an Accugage AG24 video metrology system. FIG. 64 shows an overall view of the micro-structure array and to the right a magnified view (the small divisions on the scale are 1 mm). This example demonstrates the ability to produce a precision micro-structure array over a large area using a TLM™ mold. Each feature in a quadrant of the array has a unique x, y and z orientation, but the individual structures are somewhat simple and repetitive in terms of shape. Examples 2 and 3 are presented to show how more complex features within an array can be produced using the LAMMS™ process. The second example, shown in FIG. 65, was chosen to illustrate a micro-structure array designed to increase the surface area of a single structure by a factor of four. The structures are tapered columns with corrugated ridges forming precise slots in the Z axis. The high-surface area columns were derived from a TLM™ mold using a platinum cure silicone rubber. The TLM™ mold was fabricated using photo-chemically etched, 75 micron thick copper foils which were precision stack laminated. The foils were bonded using a high-strength, thermal cure epoxy. This high-surface area micro-structure has the following dimensional characteristics: 1020 arrayed 3D micro-columns 75×75 millimeter array area 54 circular slots on each column 75 micron width×215 micron deep slots Column height 8.3 mm Another example involving complex 3D structures is shown in FIG. 66. This was produced using a TLM™ mold comprised of six photo-chemically machined stainless steel layers. Each layer in the mold had a thickness of 150 microns. The layers were laminated together using a eutectic CuSil™ (copper/silver) metal brazing process. The mold was designed to survive high-volume molding using a high-strength, flexible polymer casting resin to form the final part. FIG. 66 shows a magnified view of the cast 3D structures. A square-shaped structure was chosen for this example to further demonstrate the versatility of lithography. Features of these structures include: Cast Polymer Micro-Structures Micro-Structure Array=20×60 Top and Bottom Surface 870×870 microns Center Surface 1.035×1.035 mm Micro Structure Height 900 microns FIG. 67 is a photomicrograph of an exemplary 7-layer microstructure formed via an exemplary method described herein. FIG. 68 is a photomicrograph of an exemplary array of microstructures formed via an exemplary method described herein. FIG. 69 is a photomicrograph of a surface of an exemplary microstructure formed via an exemplary method described herein. Note that the layers and/or features of a mold can be reflected in the microstructure and/or molded part. Although this is at least implied in FIG. 57, this is particularly apparent in FIGS. 65 and 66, each of which show a plurality of monolithic microstructures each having protruding undercuts created by one or more molds from which the microstructure is descended and/or reflecting protruding undercuts of such a mold(s). The reflection, impression, and/or artifacts of the mold layers are also shown in FIGS. 67, 68, and 69 for various microstructures. The smooth wall of the hexagonal stack and the rectangular stack at the slice mark in the foreground of FIG. 68 make apparent the fact that these microstructures are monolithic and/or unitary molded structures. That is, FIG. 68 shows that one of the microstructures sliced to reveal a solid, layer-less interior volume having periphery defined by an outer surface, at least one outer surface of each of the microstructures comprising a plurality of 3-dimensional micro-features that substantially spatially invertedly replicate a mold surface formed by a plurality of layers of a metallic foil stack lamination parent mold. That is, by reflecting and/or invertedly reproducing the surface of the parent mold, the outer surface of each hexagonal column appears to suggest that the column is a stack of layers. Yet the cut-away view shows that the column is layer-less in its interior, the column only showing artifacts, such as protruding undercuts, of the layers of the parent mold on the surface of the column. FIG. 69 illustrates that the surface of an exemplary microstructure formed via an exemplary method described herein can comprise a plurality of 3-dimensional micro-features that substantially spatially invertedly replicate a mold surface formed by a plurality of layers of a metallic foil stack lamination parent mold. That is, FIG. 69 makes apparent that the layers of the mold are reflected at the edges, surfaces, and/or interfaces (e.g., at the outer edges and within the holes) of these microstructures and/or molded parts. Potential Fields of Application a. Transportation Industry Technology Areas: Weight reduction Low inertia for dynamic components Impact resistance Vibration damping Acoustic abatement Electrical insulation Inertial measurement RF technology Communications Active structures and surfaces HydrodynamicsRepresentative Devices: conformable MEMS (active and passive) micro-satellite components micro combusters micro turbines micro-thrusters RF switches antennas phase shifters displays optical switches accelerometers gyroscopes rate sensors vibration sensors mass sensors pressure sensors temperature sensors viscosity sensors density sensors humidity sensors corrosion sensors capacitive sensors temperature regulators fuel cells fuel processors nozzle technology valves and regulators pumps filters relays actuators heatersb. Biological and BiotechnologyTechnology Areas: Micro-fluidics Microbiology DNA assays Chemical testing Chemical processing Lab-on-a-chip Tissue engineering Analytical instrumentation Bio-filtration Test and measurement Bio-computing Biomedical imagingRepresentative Devices: biosensors bioelectronic components reaction wells microtiterplates pin arrays valves pumps bio-filters tissue scaffolding cell sorting and filtration membranesc. Medical (Diagnostic and Therapeutic)Technology Areas: Imaging Computed tomography Angiography Fluoroscopy Radiography Interventional radiography Orthopedic Cardiac and vascular devices Catheter based tools and devices Non-invasive surgical devices Medical tubing Fasteners Surgical cutting toolsRepresentative Devices: airways balloon catheters clips compression bars drainage tubes ear plugs hearing aids electrosurgical hand pieces and tubing feeding devices balloon cuffs wire/fluid coextrusions lumen assemblies infusion sleeves/test chambers introducer tips/flexible sheaths seals/stoppers/valves septums stents shunts membranes electrode arrays ultra-sound transducers infra-red radiation sensors radiopaque targets or markers collimators scatter grids detector arraysd. MilitaryTechnology Areas: Weapon safeing Arming and fusing Miniature analytical instruments Biomedical sensors Inertial measurement Distributed sensing and control Information technology RF devicesRepresentative Devices: MEMS fuse/safe-arm devices ordinance guidance and control devices gyroscopes accelerometers disposable sensors spectrometers active MEMS surfaces (large area) micro-mirror MEMS displays antennas switches phase shifters capacitors resistors conductors inductors exciters transmitters filters receivers voltage regulators power regulators current regulators In the transportation industry, such as the aerospace industry, exemplary embodiments can comprise multi-layer composite components, such as wings, ailerons, rotors, panels, doors, shrouds, and/or cowlings, etc. For such components, layers underlying the external “skin” can be constructed to optimize the component generally and/or in any specific and/or predetermined layer and/or location(s) within the component for functions, properties, and/or attributes such as material composition; density; weight; strength; impact resistance; stiffness; deflection; fatigue resistance; permeability; diffusion rate; texture; color; opacity; attachment points; cooling; vibration damping; acoustic damping; stealth properties; electromagnetic properties; conductivity; thermal insulation; heat transfer; wire, cable and/or conduit routing; fluid routing; penetration and/or leak detection; and/or environmental sensing, etc. The external skin can be optimized generally and/or in locally for functions, properties, and/or attributes such as surface finish; impact resistance; hardness; corrosion resistance; reflectance; color; opacity; electrical conductivity; thermal conductivity; permeability; etc. For example, the ability for helicopters to safely fly or even fly at all can be influenced by damage to the helicopter's rotor. To alert a helicopter's pilot to such damage during flight, the interior of the rotor is typically pressurized with nitrogen and the pressure of the nitrogen monitored, so that substantial penetrations of the rotor's skin result in a detectable pressure drop. By utilizing the herein described LAMMS™ technology, numerous orifices, pressure sensors, and communications networks can be built into the rotor in selected locations such that a more precise location of any substantial leaks can be determined, thereby allowing the pilot to make a more informed decision about the severity of the influence of the leak upon the helicopter's flightworthiness. That is, certain detected leaks might be tolerable and of insignificant impact on the ability of the helicopter to continue to fly safely. Other leaks, whether in critical locations or of critical size, can have a significant impact. Similarly, exterior and/or interior components, such as panels, doors, hoods, fenders, shrouds, and/or cowlings for automobiles, trucks, and/or marine vessels can utilize the LAMMS™ technology described herein to generally and/or locally optimize the component for any of the herein described functions, properties, and/or attributes. For example, for racing yachts and/or other marine vessels, utilizing the LAMMS™ technology described herein, hulls and/or hull surfaces can be constructed using a fish-scale type design, the fish scales varying in locations, dimensions, and/or properties as desired and/or for optimal hydrodynamic performance. In another example, the housing of a computer and/or other electronic or electrical device can utilize the LAMMS™ technology described herein to generally and/or locally optimize the housing for any of the herein described functions, properties, and/or attributes. For example, the housing could integrate redundant and/or non-redundant acoustic damping elements; cooling channels; mechanical vibration damping features; stiffeners; electrical conductors; electromagnetic shielding; etc. For another example, hook and loop fastener systems can be created utilizing the herein described LAMMS™ technology for creating redundant and/or non-redundant hooks and/or loops, such as hooks that vary in density and/or length across a particular dimension of hook material. A specific application for such a fastening system is a baby diaper having a hook and loop closure with a varying pattern of hooks and/or loops. The pattern can be constructed such that the closure is rather difficult, particularly for a child, to initiate opening by separating the hooks from the loops, but once opening is initiated, completing the opening requires much less pulling force than would be required if substantially uniform hooks and loops were utilized for the closure. Such a pattern can feature a predetermined variable hook and/or loop density, and/or hooks of predetermined varying lengths, orientations, stiffness, material composition, etc. An additional application for the herein described LAMMS™ technology is to create a grinding wheel that is customized to the particular part (e.g., lens, blade, etc.) it is intended to grind. The wheel can have grinding functions, properties, and/or attributes (e.g., abrasiveness, hardness, density, surface finish, material; etc.) that vary across its face in correspondence and/or relevance to the grinding needs of the part with which the wheel will interface. In another application, a transdermal patch can utilize the herein described LAMMS™ technology to provide multiple functional layers and/or generally and/or locally optimized functions, properties, and/or attributes. For example, a particular layer, perhaps in a particular location, can encompass a desired pharmaceutical, chemical, radioactive, and/or biological substance that can aid in treatment. Additional applications can involve the utilization of the herein described LAMMS™ technology for large area and/or pixelated sensors or detectors. For example, a large area neutron detector can utilize selectively conductive layers separated by a dielectric material through which an array of gas-filled wells is formed. In another example, the LAMMS™ technology can be used to form a pixelated radiography screen, the screen comprising a plurality of wells each containing a phosphor element. Hierarchical Tessellation Structures (HTS)—a New Class of Periodic Cellular Structure Engineering Concept A: Tessellation Tessellation is the juxtaposition of shapes into a pattern of contiguous polygons. As shown in FIG. 70, hexagons, rectangles, and isosceles triangles can be arrayed in three dimensions to create honeycomb, orthogrid, and isogrid structures, respectively. One purpose and/or use of such structures is to increase and/or maximize open volume, which can reduce the overall weight of the structure. Engineering Concept B: Fractals Fractals are scalable, self-similar, geometric patterns mathematically defined by precise, iterative functions. FIG. 71 illustrates some exemplary embodiments of fractal patterns that can be created via various exemplary embodiments described herein. At least some cells within any of the aforementioned tessellation structures can subdivided into smaller, self-similar cells. One purpose of such structures is to decrease and/or minimize open area, which can increase density and/or enhance associated material and/or structural properties. Combining these two concepts can give rise to a Hierarchical Tessellation Structure wherein the geometry, scale, and/or distribution of cells can be manipulated into continuous gradients to improve and/or optimize the strength-to-weight ratio of a structure, create substantially uniform load paths (distribution) within the structure, and/or enable more efficient transfer of loads to adjoining structures. These structures, which can be derived via a method described herein, also can exhibit low part-to-part variation in weight and/or dimensional accuracy. By varying the architecture of individual plies within a multi-ply, laminated structure, precisely engineered cavities and passageways can be created to embed remote sensing systems for structural health monitoring and/or real-time battle damage assessment. The geometry, scale, and/or distribution of cells can be determined by means of a Finite Element Analysis stress model. The design process can correlate cell architecture with the concentrations of stress generated (within the structure) by applied loads, which can enable and more and/or most parsimonious use of materials. FIG. 72 illustrates an exemplary output of an exemplary finite element analysis, showing areas of higher and lower stress values, and an approximate relative size of corresponding structures that can be used to accommodate those stress values, with larger structures corresponding to lower stress values and smaller structures used for accommodating higher stress values. FIG. 73 shows a perspective view of an exemplary isogrid structure that can be constructed based on such an output of a finite element analysis. Application-specific materials can be combined to achieve desired and/or superior performance in such systems as low observable (‘stealth”) structures, ballistic impact resistant structures, and/or high-cycle fatigue resistant structures. Attributes of this technology can include, but are not limited to: Design agility; Facilitates carbon fiber panel lay-up by integral membranes (closed cells) on outer plies; Large area (square meter) capability; Reduction of septa (ligament) volume; Reduction in core density; Isotropic mechanical properties; Increased resistance to rib buckling; Increase mechanical strength of shear planes; Variable rigidity (flexibility); and/or Energy absorbing core structures. Certain exemplary embodiments can provide large area micro-mechanical systems (sometimes referred to herein as “LAMMS”), which can be Finite Element Analysis (“FEA”) driven; custom mesostructure per FEA element; variable geometry and distribution; arrays of mm3-scale mesostructures over m2 areas; multi-functional materials; synthetic composites; multi-ply, laminated structures; and/or low weight; high performance. Certain exemplary embodiments can provide advanced core structures, which can comprise and/or be characterized by: multi-layer lamination; isogrid cell motif; loads-defined cell topography; carbon fiber face and/or back sheets; large area capability, on the scale of approximately 1 to 10 square meters; a density of approximately 19 kg/cubic meter for a cell size of 20 mm; varying cell concentrations in a continuous gradient; parsimonious use of materials; and/or uniform load distributions. Certain exemplary embodiments can provide an isogrid cell motif, which can provide and/or be characterized by: an inherent resilience to tensile, compressive, shear, and/or bending loads; redundant load paths; resistance to impact, delamination, and/or crack propagation; optimization for a wide range of load intensities, superior strength to weight ratio. Certain exemplary embodiments can provide an isogrid cell motif, which, from the perspective of and/or to accommodate compressive loads, can provide and/or be characterized by: a variety of rib and/or ligament thicknesses; expanded and/or condensed grid patterns; decreased aspect ratio; increased numbers of plies; grid patterns that are offset from one layer to the next; isotropic properties; and/or resistance to rib buckling. Certain exemplary embodiments can provide an isogrid cell motif, which, from the perspective of and/or to accommodate shear loads, can provide and/or be characterized by: increased surface area; closed cells on the bond line; increased interface adhesion; textured surfaces; interlocking plies; male and female interlock components; and/or optimizable mechanical strength of shear planes. Certain exemplary embodiments can provide an advanced multi-functional armor system, which, can provide and/or be characterized by: projectile and/or fragment defeat; blast mitigation (Behind Armor Blunt Trauma); multiple strike protection; enhanced mobility; light weight; scalable systems; low cost; high modulus outer skin; and/or an energy absorbing and/or redirecting core; a polymer matrix core; a ballistic barrier and/or ceramic back face; and/or a spall shielding (e.g., Kevlar) back face. Certain exemplary embodiments described herein can be used to construct products, devices, assemblies, machines, and/or systems, such as those described herein and/or such as a sporting good, tennis racket, golf club shaft, fishing rod, hockey stick, backboard, goalpost, bicycle and/or motorcycle frame, fork, handlebar, seatpost, crank arm, wheel, mudflap, equestrian saddle, saddle tree, kayak, paddle, ski, ski pole, skate, skate blade, snowboard, surfboard, skateboard, helmet, guard, paintball equipment, gunstock, ballistic armor, armor, boat and/or ship hull, deck, superstructure, mast, marine equipment, satellite shell, antenna, solar panel, radome, aircraft wing, fuselage, fairing assembly, airframe, elevator, rudder, landing gear, propeller, helicopter airfoil (rotor blade), windmill airfoil (blade), turbine blade, engine component, engine exhaust shroud, exhaust baffle, driveshaft, acoustic shroud, acoustic baffle, cockpit sidewall, ceiling panel, doorliner, door panel, hood, fender, bonnet, fairing, bumper, tailgate, spoiler, bed, quarter panel, roof, pillar, floorboard, sidewall, dashboard, instrument panel, headliner, trunk deck, firewall, bulkhead, seat frame, leaf spring, wheel, rail, wall, floor support, flooring, door, window frame, railing, siding, chassis, frame, conduit, duct, pipe, pressure vessel, tank, equipment, pump, fan, damper, machine tool, robot arm, equipment housing, enclosure, fire resistant enclosure and/or panel, fireproof enclosure and/or panel, computer enclosure, keyboard, display, loud speaker, tripod, engine component, flywheel, footing, structural column, structural beam, truss, structural wall, divider, impact absorber, guardrail, signpost, light pole, power pole, structural pole, architectural signage, signage substrate, billboard substrate, tool, handle, footwear, toy, musical instrument, casket, gurney, bed frame, furniture, shelving, cabinetry, countertop, hot tub, tub, shower enclosure, pet crate, packaging, composite part, and/or composite structure, etc. Certain exemplary embodiments described herein can be used to construct products, devices, assemblies, machines, and/or systems, such as those typically constructed using fiberglass reinforced plastic, carbon fiber reinforced plastic, fiber reinforced matrix systems, honeycombed sandwich structures, and/or sandwiched composite structures. Certain exemplary embodiments can provide a first isogrid defining a first plurality of zones, each zone from said first plurality of zones comprising a plurality of ligaments, each zone from said first plurality of zones defining a plurality of spaces, each space bounded by a first sub-plurality of ligaments from said plurality of ligaments, each of said ligaments comprising a plurality of ligament surfaces. Certain exemplary embodiments can provide a system comprising: a first cast isogrid defining a first plurality of zones, each zone from said first plurality of zones comprising a plurality of cast ligaments, each zone from said first plurality of zones defining a plurality of triangular spaces, each triangular space bounded by a first sub-plurality of cast ligaments from said plurality of cast ligaments, an interlock defined at an intersection of a second sub-plurality of cast ligaments from said plurality of cast ligaments, each of said cast ligaments comprising a plurality of ligament surfaces, for each of said ligaments, a ligament surface from said plurality of ligament surfaces comprising a plurality of 3-dimensional micro-features that substantially spatially invertedly replicate a mold surface formed by a plurality of layers of a metallic foil stack lamination parent mold, said plurality of 3-dimensional micro-features comprising at least one protruding undercut, said plurality of ligament surfaces for each of said ligaments defining a periphery of a layer-less volume. Engineering specimens were produced to demonstrate the ability to design and/or fabricate an advanced multi-layer structural composite using TLM manufacturing. The specimen embodied engineered features including: high strength ISO grid configuration, controlled corner radii at cell intersection points to eliminate or reduce fracture points, varying sized interconnected cell configurations, recessed nodes at intersections for sensor embedding or fastening points, and 45 micron bump and cavity arrays on grid ligament (and back plane surface) to promote multi-layer adhesive bonding. Figure # X shows dimensional specifications of the specimen. Specimens were produced using methods described in U.S. patent application Ser. No. 10/479,335 and/or herein. Methods for manufacturing three-dimensional devices and devices created thereby. Specimen manufacturing methods can include CAD generation, photo-mask generation, metallic foil etching, stack lamination, mold production, and/or casting. Both open and closed molds were used to produce the specimens. Specimens were produced using a low CTE two part epoxy (Epo-tek 301-2) and a flexible polyurethane (Resin Lab EP1218). Specimens were also produced by loading the two part epoxy with carbon powder (200 mesh obtained from Grupo Rooe, S.A. de c.v. Mexico) prior to casting. The epoxy was loaded with varying amounts of carbon powder including 20%, 30%, and 40% by weight. Engineering specimens were produced to demonstrate the ability to design and fabricate an advanced multi-layer structural composite using TLM manufacturing. The following design specifications were embodied in the specimen: overall size 20×20 CM, 1.500 mm open hexagonal cells, cells arrayed in two regions (slant hole region and progressive angle cell region), 2.0 mm total specimen thickness. Open cells arrayed in “progressive angle cell region” decrease in angular position from 90 degrees at the focal point to 36.7 degrees at the border of the “slant hole region”. Open cells remain constant in the “slant hole region” at an angle of 37.5 degrees. Cell angles and regions are shown in Figure X. Software code written in Visual Basic was used as a means of configuring the angles of the cell openings in the specimen. Each layer of the TLM mold (stack lamination) had unique cell positions on each layer to produce the angled cells. The Visual Basic program was imported into AutoCad software which was then used to create a DXF file. The DXF files were used to plot the CAD data to film for photo-mask generation. Using Visual Basic, an event driven programming language for graphical user interface applications, such as AutoCAD, we can implement the appropriate algorithms for the desired engineered design. We can manipulate patterns across a surface as well as create 3D structures within a volume with layer-to-layer pattern variations. Example Algorithms 3D slant hole geometry can be created by programming the following algorithm into Visual Basic for specific z locations. For integers i and j=1→ integer value and dR, pitch_X and pitch_Y=constants, then the insertion point could be defined:X=(pitch—X*i)+(dX*Z) Y=(pitch—Y*j)+(dY*Z)where Z=location in z-axis, dX = dR * ( pitch_X * i pitch_Y * j ) ( pitch_X * i pitch_Y * j ) 2 + 1 and dY = dR ( pitch_X * i pitch_Y * j ) 2 + 1 Specimens were produced using methods described in U.S. patent application Ser. No. 10/479,335. Methods for manufacturing three-dimensional devices and devices created thereby. Specimen manufacturing methods include CAD generation (described above), photo-mask generation, metallic foil etching, stack lamination, mold production, and casting. Both open and closed molds were used to produce the specimens. Specimens were produced using a low CTE two-part epoxy (Epo-tek 301-2) and flexible polyurethane (Resin Lab EP1218). Specimens were also produced by loading the two part epoxy with carbon powder (200 mesh obtained from Grupo Rooe, S.A. de c.v. Mexico) prior to casting. The epoxy was loaded with varying amounts of carbon powder including 20%, 30%, and 40% by weight. FIG. 74 is a perspective view of an exemplary embodiment of a cast isogrid 74000, which can comprise multiple zones 74100, 74200, 74300, 74400. Each zone can comprise multiple ligaments 74500, 74600, which can join at an intersection and/or node 74700. FIG. 75A and FIG. 75B are a top and side views, respectively of an exemplary embodiment of a male interlocking isogrid 75100, and FIG. 75C and FIG. 75D are a top and side views, respectively of an exemplary embodiment of a female interlocking isogrid 75200. Any isogrid 75100, 75200 can comprise multiple ligaments 75300, which can join at an intersection and/or node 75400, and which can define spaces, such as triangular space 75500. A maximum dimension measured between a pair of ligaments defining a triangular space 75500 can be, for example, from approximately 0.0625 inches to approximately 0.375 inches, including all values and subranges therebetween, such as from approximately 0.1875 inches to approximately 0.375 inches. Each ligament can have a variable and/or substantially uniform thickness, such as a thickness of from approximately 0.0007 inches to approximately 0.005 inches, including all values and subranges therebetween. A ligament 75300 can comprise a ligament surface 75600, which can comprise a plurality of 3-dimensional micro-features that substantially spatially invertedly replicate a mold surface formed by a plurality of layers of a metallic foil stack lamination parent mold, said plurality of 3-dimensional micro-features comprising at least one protruding undercut, said plurality of ligament surfaces for each of said ligaments defining a periphery of a layer-less volume, such as shown in FIG. 68. FIG. 76 is a block diagram of an exemplary embodiment of an information device 76000, which in certain operative embodiments can comprise, for example, a computer, such as a computer used to perform a finite element analysis. Information device 76000 can comprise any of numerous components, such as for example, one or more network interfaces 76100, one or more processors 76200, one or more memories 76300 containing instructions 76400, one or more input/output (I/O) devices 76500, and/or one or more user interfaces 76600 coupled to I/O device 76500, etc. In certain exemplary embodiments, via one or more user interfaces 76600, such as a graphical user interface, a user can view a rendering of information related to researching, designing, modeling, creating, developing, building, manufacturing, operating, maintaining, storing, marketing, selling, delivering, selecting, specifying, requesting, ordering, receiving, returning, rating, and/or recommending any of the products, services, methods, and/or information described herein. FIG. 77A is a top view of an exemplary embodiment of a system 77000, and FIG. 77B is a front view of an exemplary embodiment of the system 77000 of FIG. 77A. System 77000 comprises isogrid 77100 and isogrid 77200, as well as an isogrid tiling positioner 77300 formed by features of isogrid 77100 and isogrid 77200 at multiple layers of each isogrid. Thus, in this exemplary embodiment, isogrid tiling positioner 77300 serves as an interlocking isogrid stacking positioner, because it constrains and/or prevents movement of isogrid 77100 with respect to isogrid 77200 in the Z direction, and serves as an isogrid tiling positioner because it constrains and/or prevents movement of isogrid 77100 with respect to isogrid 77200 in the X direction and/or Y direction. FIG. 78A is a top view, and FIG. 78B is a front view, of an exemplary embodiment of a system 78000 comprising a channeled isogrid 78100 comprising channels 78200, 78300 within a plurality of its ligaments. Such channels can provide a variety of uses, such as conveying fluids, positioning electrical conductors, and/or positioning optical waveguides. FIG. 79A is a top view of an exemplary embodiment of a system 79000 comprising an isogrid 79200 attached to a face plate 79100. FIG. 79B is a front view of an exemplary embodiment of system 79000 of FIG. 79A, in which isogrid 79200 and face plate 79100 are positioned adjacent and in parallel flat planes. FIG. 79C is a front view of an exemplary embodiment of system 79000 of FIG. 79A, in which isogrid 79200 and face plate 79100 are positioned adjacent and in parallel curved planes. FIG. 80A is a top view of an exemplary embodiment of a system 80000 comprising an isogrid 80200 attachable to a face plate 80100 via one or more male isogrid stacking positioners 80300, which can be located along a ligament 80220 and/or at a node 80240 where ligaments intersect. FIG. 80B is a front view of an exemplary embodiment of system 80000 of FIG. 80A, showing a plurality of female isogrid stacking positioners 80400, and that isogrid 80200 and face plate 80100 can be positioned in adjacent parallel flat planes. FIG. 80C is a front view of an exemplary embodiment of system 80000 of FIG. 80A, showing a plurality of female isogrid stacking positioners 80400, and that isogrid 80200 and face plate 80100 can be positioned in adjacent parallel curved planes. FIG. 81A is a top view of an exemplary embodiment of a system 81000 comprising a isogrid stacking positioner 81300 located at a node 81200 of an isogrid 81100. FIG. 81B is a front view of an exemplary embodiment of system 81000 of FIG. 81A, and showing that isogrid stacking positioner 81300 can be male, thereby serving as a mechanical positioner. FIG. 82A is a top view of an exemplary embodiment of a system 82000 comprising an isogrid stacking positioner 82300 located at a node 82200 of an isogrid 82100. FIG. 82B is a front view of an exemplary embodiment of system 82000 of FIG. 82A, and showing that isogrid stacking positioner 82300 can be female, thereby serving as a mechanical positioner. FIG. 82C is a front view of an exemplary embodiment of system 82000 of FIG. 82A, and showing that isogrid stacking positioner 81300 can be a through hole, thereby serving as a visual and/or optical positioner. FIG. 83A is a top view, and FIG. 83B is a front view, of an exemplary embodiment of a system 83000 comprising a fillet 83300 joining two ligaments 83400, 83500 at a node 83200 of an isogrid 83100, the fillet 83300 having a radius R. FIG. 84 is a top view of an exemplary embodiment of a system 84000 comprising a substantially circular node 84200 joining a plurality of ligaments of an isogrid 84100. FIG. 85 is a top view of an exemplary embodiment of a system 85000 comprising a first isogrid 85100 comprising a male isogrid tiling positioner 85300 located at a predetermined position along a ligament of first isogrid 85100 and adapted constrain and/or interlock first isogrid 85100 relative to a second isogrid 85200 via mating with a female isogrid tiling positioner 85400 located at a corresponding predetermined position along a ligament of second isogrid 85200. FIG. 86 is a top view of an exemplary embodiment of a system 86000 comprising a first isogrid 86100 comprising a male isogrid tiling positioner 86300 located at a node of first isogrid 86100 and adapted constrain, connect, and/or interlock first isogrid 86100 relative to a second isogrid 86200 via mating with a female isogrid tiling positioner 86400 located at a corresponding node of second isogrid 86200. Depending on the precise configuration, dimensions, and/or material properties of male isogrid tiling positioner 86300 and/or female isogrid tiling positioner 86400, the interlock formed thereby can be either non-destructively releasable, thereby allowing first isogrid 86100 to be easily released and reunited with second isogrid 86200, such as to facilitate testing, repair, and/or maintenance, or destructively releasable, thereby preventing first isogrid 86100 from being easily released and/or reunited with second isogrid 86200. When the following terms are used substantively herein, the accompanying definitions apply. These terms and definitions are presented without prejudice, and, consistent with the application, the right to redefine these terms during the prosecution of this application or any application claiming priority hereto is reserved. For the purpose of interpreting a claim of any patent that claims priority hereto, each definition (or redefined term if an original definition was amended during the prosecution of that patent), functions as a clear and unambiguous disavowal of the subject matter outside of that definition. 3-dimensional—involving or relating to three mutually orthogonal dimensions. a—at least one. activity—an action, act, step, and/or process or portion thereof. adapted to—suitable, fit, and/or capable of performing a specified function. adjacent—in close proximity to, near, next to, and/or adjoining align—to place objects such that at least some of their faces are in line with each other and/or so that their centerlines are on the same axis. all—an entirety of a set. along—through, on, beside, over, in line with, and/or parallel to the length and/or direction of; and/or from one end to the other of and/or—either in conjunction with or in alternative to. apparatus—an appliance or device for a particular purpose approximately—about and/or nearly the same as. associate—to join, connect together, and/or relate. at least one—not less than one, and possibly more than one. attach—to fasten, secure, couple, and/or join. automatically—acting or operating in a manner essentially independent of external influence or control. For example, an automatic light switch can turn on upon “seeing” a person in its view, without the person manually operating the light switch. average—a value obtained by dividing the sum of a set of quantities by the number of quantities in a set and/or an approximation of a statistical expected value. between—in a separating interval and/or intermediate to. bound—to limit an extent. can—is capable of, in at least some embodiments. cast—formed in a mold. cause—to produce an effect. channel—a defined passage, conduit, and/or groove for conveying one or more fluids. characterize—to define, describe, classify, and/or constrain the qualities, characteristics, and/or peculiarities of. circular—round and/or having the shape of a circle. compressive—pertaining to forces on a body or part of a body that tend to crush and/or compress the body. comprises—includes, but is not limited to, what follows. comprising—including but not limited to. configure—to make suitable or fit for a specific use or situation. connect—to join or fasten together. convert—to transform, adapt, and/or change. corresponding—related, associated, accompanying, similar in purpose and/or position, conforming in every respect, and/or equivalent and/or agreeing in amount, quantity, magnitude, quality, and/or degree. coupleable—capable of being joined, connected, and/or linked together. coupling—linking in some fashion. create—to bring into being. data—distinct pieces of information, usually formatted in a special or predetermined way and/or organized to express concepts. data structure—an organization of a collection of data that allows the data to be manipulated effectively and/or a logical relationship among data elements that is designed to support specific data manipulation functions. A data structure can comprise meta data to describe the properties of the data structure. Examples of data structures can include: array, dictionary, graph, hash, heap, linked list, matrix, object, queue, ring, stack, tree, and/or vector. define—to establish the meaning, relationship, outline, form, and/or structure of; and/or to precisely and/or distinctly describe and/or specify. determine—to obtain, calculate, decide, deduce, and/or ascertain. device—a machine, manufacture, and/or collection thereof. differ—to be unlike, dissimilar, and/or distinct in nature and/or quality. dimension—an extension in a given direction and/or a measurement in length, width, or thickness. direction—a spatial relation between something and a course along which it points and/or moves; a distance independent relationship between two points in space that specifies the position of either with respect to the other; and/or a relationship by which the alignment and/or orientation of any position with respect to any other position is established. each—every one of a group considered individually. embodiment—an implementation and/or a concrete representation of a concept. exemplary—serving as a model. extending—existing, located, placed, and/or stretched lengthwise. face—the most significant or prominent surface of an object. fillet—concave easing of an interior corner of a part design. first—an initial entity in an ordering of entities; immediately preceding the second in an ordering. foil—a very thin, often flexible sheet and/of leaf, typically formed of metal. formations—concave and/or convex elements on a surface; dimples; and/or protrusions. formed—constructed. from—used to indicate a source. further—in addition. generate—to create, produce, give rise to, and/or bring into existence. haptic—involving the human sense of kinesthetic movement and/or the human sense of touch. Among the many potential haptic experiences are numerous sensations, body-positional differences in sensations, and time-based changes in sensations that are perceived at least partially in non-visual, non-audible, and non-olfactory manners, including the experiences of tactile touch (being touched), active touch, grasping, pressure, friction, fraction, slip, stretch, force, torque, impact, puncture, vibration, motion, acceleration, jerk, pulse, orientation, limb position, gravity, texture, gap, recess, viscosity, pain, itch, moisture, temperature, thermal conductivity, and thermal capacity. having—possessing, characterized by, and/or comprising. information device—any device capable of processing data and/or information, such as any general purpose and/or special purpose computer, such as a personal computer, workstation, server, minicomputer, mainframe, supercomputer, computer terminal, laptop, wearable computer, and/or Personal Digital Assistant (PDA), mobile terminal, Bluetooth device, communicator, “smart” phone (such as a Treo-like device), messaging service (e.g., Blackberry) receiver, pager, facsimile, cellular telephone, a traditional telephone, telephonic device, a programmed microprocessor or microcontroller and/or peripheral integrated circuit elements, an ASIC or other integrated circuit, a hardware electronic logic circuit such as a discrete element circuit, and/or a programmable logic device such as a PLD, PLA, FPGA, or PAL, or the like, etc. In general any device on which resides a finite state machine capable of implementing at least a portion of a method, structure, and/or or graphical user interface described herein may be used as an information device. An information device can comprise components such as one or more network interfaces, one or more processors, one or more memories containing instructions, and/or one or more input/output (I/O) devices, one or more user interfaces coupled to an I/O device, etc. input/output (I/O) device—any sensory-oriented input and/or output device, such as an audio, visual, haptic, olfactory, and/or taste-oriented device, including, for example, a monitor, display, projector, overhead display, keyboard, keypad, mouse, trackball, joystick, gamepad, wheel, touchpad, touch panel, pointing device, microphone, speaker, video camera, camera, scanner, printer, haptic device, vibrator, tactile simulator, and/or tactile pad, potentially including a port to which an I/O device can be attached or connected. install—to connect or set in position and prepare for use. integral—formed or united into another entity. interlock—(v) to fit, connect, unite, lock, and/or join together and/or closely in a non-destructively and/or destructively releasable manner; (n) a device for non-destructively and/or destructively releasably preventing substantial relative motion between two elements of a structure. intersection—a point and/or line segment defined by the meeting of two or more items. invert—to reverse the position, order, condition, nature, and/or effect of invertedly—in an reversed and/or opposing position, order, condition, nature, and/or effect. isogrid—a structural arrangement formed of a lattice of intersecting ligaments that define one or more arrays of triangular spaces. isogrid positioner—a mechanical, optical, and/or magnetic feature adapted to constrain, locate, and/or align the position of one isogrid relative to an adjacent isogrid. isogrid stacking positioner—a mechanical, optical, and/or magnetic feature adapted to constrain, locate, and/or align the position of a first isogrid relative to an adjacent second isogrid whose lattice spans in a substantially parallel, but non-coplanar, flat and/or curved plane as the first isogrid. isogrid tiling positioner—a mechanical, optical, and/or magnetic feature adapted to constrain, locate, and/or align the position of a first isogrid relative to an adjacent second isogrid whose lattice spans in substantially the same flat and/or curved plane as the first isogrid. laminate—to construct from layers of material bonded together. lamination—a bonded, adhered, and/or attached structure and/or arrangement, typically formed of thin sheets; and/or a laminated structure and/or arrangement. layer—a single thickness of a material covering a surface or forming an overlying part or segment. layer-less—not formed of, and/or lacking a collection and/or stack of, plies, strata, and/or sheets. less than—having a measurably smaller magnitude and/or degree as compared to something else. ligament—a connecting member such as a wall, beam, and/or rib. located—situated in a particular spot and/or position. machine instructions—directions adapted to cause a machine, such as an information device, to perform one or more particular activities, operations, or functions. The directions, which can sometimes form an entity called a “processor”, “kernel”, “operating system”, “program”, “application”, “utility”, “subroutine”, “script”, “macro”, “file”, “project”, “module”, “library”, “class”, and/or “object”, etc., can be embodied as machine code, source code, object code, compiled code, assembled code, interpretable code, and/or executable code, etc., in hardware, firmware, and/or software. machine readable medium—a physical structure from which a machine can obtain data and/or information. Examples include a memory, punch cards, etc. maximum—a greatest extent. may—is allowed and/or permitted to, in at least some embodiments. measured—determined, as a dimension, quantification, and/or capacity, etc. by observation. memory device—an apparatus capable of storing analog or digital information, such as instructions and/or data. Examples include a non-volatile memory, volatile memory, Random Access Memory, RAM, Read Only Memory, ROM, flash memory, magnetic media, a hard disk, a floppy disk, a magnetic tape, an optical media, an optical disk, a compact disk, a CD, a digital versatile disk, a DVD, and/or a raid array, etc. The memory device can be coupled to a processor and/or can store instructions adapted to be executed by processor, such as according to an embodiment disclosed herein. metallic—comprising a metal. method—a process, procedure, and/or collection of related activities for accomplishing something. micro-features—irregularities, such as ridges and/or valleys, forming a roughness average on a surface of between approximately 1 microns and approximately 500 microns. misaligned—to place out of alignment and/or to offset. mold—(n) a substantially hollow form, cavity, and/or matrix into and/or on which a molten, liquid, and/or plastic composition is placed and from which that composition takes form in a reverse image from that of the mold; (v) to shape and/or form in and/or on a mold. network—a communicatively coupled plurality of nodes. A network can be and/or utilize any of a wide variety of sub-networks, such as a circuit switched, public-switched, packet switched, data, telephone, telecommunications, video distribution, cable, terrestrial, broadcast, satellite, broadband, corporate, global, national, regional, wide area, backbone, packet-switched TCP/IP, Fast Ethernet, Token Ring, public Internet, private, ATM, multi-domain, and/or multi-zone sub-network, one or more Internet service providers, and/or one or more information devices, such as a switch, router, and/or gateway not directly connected to a local area network, etc. network interface—any device, system, or subsystem capable of coupling an information device to a network. For example, a network interface can be a telephone, cellular phone, cellular modem, telephone data modem, fax modem, wireless transceiver, ethernet card, cable modem, digital subscriber line interface, bridge, hub, router, or other similar device. node—a junctions and/or intersection of a plurality of non-co-linear ligaments. non—not. offsetably—characterized by a misalignment, jog, and/or short displacement in an otherwise parallel and/or straight orientation and/or arrangement. orthogonal—perpendicular. overlappingly—characterized by extending over and covering a part of something else. packet—a discrete instance of communication. parent—an entity from which another is descended; and/or a source, origin, and/or cause. percent—one part in one hundred. periphery—the outer limits, surface, and/or boundary of a surface, area, and/or object. planar—shaped as a substantially flat two-dimensional surface. plurality—the state of being plural and/or more than one. predetermined—established in advance. processor—a device and/or set of machine-readable instructions for performing one or more predetermined tasks. A processor can comprise any one or a combination of hardware, firmware, and/or software. A processor can utilize mechanical, pneumatic, hydraulic, electrical, magnetic, optical, informational, chemical, and/or biological principles, signals, and/or inputs to perform the task(s). In certain embodiments, a processor can act upon information by manipulating, analyzing, modifying, converting, transmitting the information for use by an executable procedure and/or an information device, and/or routing the information to an output device. A processor can function as a central processing unit, local controller, remote controller, parallel controller, and/or distributed controller, etc. Unless stated otherwise, the processor can be a general-purpose device, such as a microcontroller and/or a microprocessor, such the Pentium IV series of microprocessor manufactured by the Intel Corporation of Santa Clara, Calif. In certain embodiments, the processor can be dedicated purpose device, such as an Application Specific Integrated Circuit (ASIC) or a Field Programmable Gate Array (FPGA) that has been designed to implement in its hardware and/or firmware at least a part of an embodiment disclosed herein. protrude—to bulge, jut, project, and/or extend out and/or into space. provide—to furnish, supply, give, convey, send, and/or make available. radius—the length of a line segment between the center and circumference of a circle or sphere. render—to make perceptible to a human, for example as data, commands, text, graphics, audio, video, animation, and/or hyperlinks, etc., such as via any visual, audio, and/or haptic means, such as via a display, monitor, electric paper, ocular implant, cochlear implant, speaker, etc. repeatedly—again and again; repetitively. replicate—to make a substantially identical copy, duplicate, reproduction, and/or repetition of something. said—when used in a system or device claim, an article indicating a subsequent claim term that has been previously introduced. second—immediately following the first in an ordering. select—to make a choice or selection from alternatives. set—a related plurality of predetermined elements; and/or one or more distinct items and/or entities having a specific common property or properties. set—a related plurality. shear—a deformation resulting from stresses that cause contiguous parts of a body to slide relatively to each other in a direction parallel to their plane of contact; a deformation of an object in which parallel planes remain parallel but are shifted in a direction parallel to themselves; “the shear changed the quadrilateral into a parallelogram”. sheet—a broad, relatively thin, surface, layer, and/or covering signal—information, such as machine instructions for activities, encoded as automatically detectable variations in a physical variable, such as a pneumatic, hydraulic, acoustic, fluidic, mechanical, electrical, magnetic, optical, chemical, and/or biological variable, such as power, energy, pressure, flowrate, viscosity, density, torque, impact, force, voltage, current, resistance, magnetomotive force, magnetic field intensity, magnetic field flux, magnetic flux density, reluctance, permeability, index of refraction, optical wavelength, polarization, reflectance, transmittance, phase shift, concentration, and/or temperature, etc. Depending on the context, a signal can be synchronous, asychronous, hard real-time, soft real-time, non-real time, continuously generated, continuously varying, analog, discretely generated, discretely varying, quantized, digital, continuously measured, and/or discretely measured, etc. space—an area and/or volume. spatially—existing or occurring in space. stack—a substantially orderly pile and/or group, especially one arranged in and/or defined by layers. store—to place, hold, and/or retain data, typically in a memory. strength—a measure of the ability of a material to support a load; the maximum nominal stress a material can sustain; and/or a level of stress at which there is a significant change in the state of the material, e.g., yielding and/or rupture. sub-plurality—a subset. substantially—to a considerable, large, and/or great, but not necessarily whole and/or entire, extent and/or degree. support—to bear the weight of, especially from below. surface—any face and/or outer boundary of a body, object, and/or thing system—a collection of devices, machines, articles of manufacture, and/or processes, the collection designed to perform one or more specific functions. tensile—pertaining to forces on a body that tend to stretch, or elongate, the body. A rope or wire under load is subject to tensile forces. terminate—to end. thickness—the measure of the smallest dimension of a solid figure. through—in one side and out the opposite or another side of, across, among, and/or between. transmit—to send as a signal, provide, furnish, and/or supply. triangular—pertaining to or having the form of a triangle; three-cornered. undercut—a notch, groove, and/or cut beneath. user interface—any device for rendering information to a user and/or requesting information from the user. A user interface includes at least one of textual, graphical, audio, video, animation, and/or haptic elements. A textual element can be provided, for example, by a printer, monitor, display, projector, etc. A graphical element can be provided, for example, via a monitor, display, projector, and/or visual indication device, such as a light, flag, beacon, etc. An audio element can be provided, for example, via a speaker, microphone, and/or other sound generating and/or receiving device. A video element or animation element can be provided, for example, via a monitor, display, projector, and/or other visual device. A haptic element can be provided, for example, via a very low frequency speaker, vibrator, tactile stimulator, tactile pad, simulator, keyboard, keypad, mouse, trackball, joystick, gamepad, wheel, touchpad, touch panel, pointing device, and/or other haptic device, etc. A user interface can include one or more textual elements such as, for example, one or more letters, number, symbols, etc. A user interface can include one or more graphical elements such as, for example, an image, photograph, drawing, icon, window, title bar, panel, sheet, tab, drawer, matrix, table, form, calendar, outline view, frame, dialog box, static text, text box, list, pick list, pop-up list, pull-down list, menu, tool bar, dock, check box, radio button, hyperlink, browser, button, control, palette, preview panel, color wheel, dial, slider, scroll bar, cursor, status bar, stepper, and/or progress indicator, etc. A textual and/or graphical element can be used for selecting, programming, adjusting, changing, specifying, etc. an appearance, background color, background style, border style, border thickness, foreground color, font, font style, font size, alignment, line spacing, indent, maximum data length, validation, query, cursor type, pointer type, autosizing, position, and/or dimension, etc. A user interface can include one or more audio elements such as, for example, a volume control, pitch control, speed control, voice selector, and/or one or more elements for controlling audio play, speed, pause, fast forward, reverse, etc. A user interface can include one or more video elements such as, for example, elements controlling video play, speed, pause, fast forward, reverse, zoom-in, zoom-out, rotate, and/or tilt, etc. A user interface can include one or more animation elements such as, for example, elements controlling animation play, pause, fast forward, reverse, zoom-in, zoom-out, rotate, tilt, color, intensity, speed, frequency, appearance, etc. A user interface can include one or more haptic elements such as, for example, elements utilizing tactile stimulus, force, pressure, vibration, motion, displacement, temperature, etc. variance—a measure of variation of a set of observations defined by a sum of the squares of deviations from a mean, divided by a number of degrees of freedom in the set of observations. via—by way of and/or utilizing. volume—a mass and/or a three-dimensional region that an object and/or substance occupies. wherein—in regard to which; and; and/or in addition to. within—inside. zone—a portion of an isogrid containing an array of substantially identically-dimensioned triangular spaces. Within such an array, certain physical properties of the isogrid and/or its ligaments (such as compressive strength, shear strength, elasticity, density, opacity, and/or thermal conductivity, etc.) can be substantially isotropic, that is, substantially equal in all directions.Note Still other substantially and specifically practical and useful embodiments will become readily apparent to those skilled in this art from reading the above-recited and/or herein-included detailed description and/or drawings of certain exemplary embodiments. It should be understood that numerous variations, modifications, and additional embodiments are possible, and accordingly, all such variations, modifications, and embodiments are to be regarded as being within the scope of this application. Thus, regardless of the content of any portion (e.g., title, field, background, summary, description, abstract, drawing figure, etc.) of this application, unless clearly specified to the contrary, such as via explicit definition, assertion, or argument, with respect to any claim, whether of this application and/or any claim of any application claiming priority hereto, and whether originally presented or otherwise: there is no requirement for the inclusion of any particular described or illustrated characteristic, function, activity, or element, any particular sequence of activities, or any particular interrelationship of elements; any elements can be integrated, segregated, and/or duplicated; any activity can be repeated, any activity can be performed by multiple entities, and/or any activity can be performed in multiple jurisdictions; and any activity or element can be specifically excluded, the sequence of activities can vary, and/or the interrelationship of elements can vary. Moreover, when any number or range is described herein, unless clearly stated otherwise, that number or range is approximate. When any range is described herein, unless clearly stated otherwise, that range includes all values therein and all subranges therein. For example, if a range of 1 to 10 is described, that range includes all values therebetween, such as for example, 1.1, 2.5, 3.335, 5, 6.179, 8.9999, etc., and includes all subranges therebetween, such as for example, 1 to 3.65, 2.8 to 8.14, 1.93 to 9, etc. When any claim element is followed by a drawing element number, that drawing element number is exemplary and non-limiting on claim scope. Any information in any material (e.g., a United States patent, United States patent application, book, article, etc.) that has been incorporated by reference herein, is only incorporated by reference to the extent that no conflict exists between such information and the other statements and drawings set forth herein. In the event of such conflict, including a conflict that would render invalid any claim herein or seeking priority hereto, then any such conflicting information in such material is specifically not incorporated by reference herein. Accordingly, every portion (e.g., title, field, background, summary, description, abstract, drawing figure, etc.) of this application, other than the claims themselves, is to be regarded as illustrative in nature, and not as restrictive. |
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053612833 | claims | 1. In a reconstitutable fuel assembly having an upper end fitting with a plurality of bores therethrough each sized to receive a guide tube assembly and at least one control rod guide tube assembly with the guide tube assembly including an upper end sleeve having a radially extending first shoulder at the lower end for engagement with the lower surface of said upper end fitting, an integral reusable locking arrangement between the guide tube assembly and upper end fitting comprising: a. said upper end sleeve having at least two rigid tabs that extend radially outward; b. said upper end fitting having a plurality of vertical slots that extend downwardly along a portion of the wall of each bore from the upper end thereof so as to define a second shoulder at the lower end of each of said slots; c. a cylindrical tube concentric with said upper end sleeve, said cylindrical tube having at least two slots sized to receive said tabs on said upper end sleeve and a plurality of flexible tabs extending outwardly and circumferentially spaced apart substantially at the mid section of said tube such that the tabs at the mid section of said tube are received in said vertical slots in the upper end fitting for engagement with said second shoulders, the lower end surface of said tube being engaged with said first shoulder. 2. The locking arrangement of claim 1, further comprising said cylindrical tube having at least two tooling slots at the upper end. 3. The locking arrangement of claim 1, further comprising said cylindrical tube having a plurality of flexible tabs that extend outwardly and are spaced apart around the circumference of the lower end of said cylindrical tube. |
description | Embodiments of the present invention relate to a particle beam transport system for transporting a particle beam from an accelerator to irradiation equipment in a treatment room and a segment thereof. There is widely known a particle beam treatment technique in which treatment is performed by irradiating a lesion tissue (cancer) of a patient with a particle beam such as a carbon ion beam. According to this particle beam treatment technique, since it is possible to kill only a lesion tissue at pinpoint without damaging normal tissues, it is less burdensome on a patient than other treatment such as surgery and medication therapy, and thus it can be expected to accelerate social reintegration after treatment. Hence, interest in particle beam treatment has increased, and it is desired to add treatment facilities in order to cope with an increase in the number of patients who desire the particle beam treatment. A particle beam treatment facility is large-scale including an accelerator for generating a particle beam. Thus, in order to reduce treatment cost and improve treatment throughput, it is under consideration to provide plural treatment rooms and branch a particle beam transport system such that the particle beam transport system is connected to the respective treatment rooms. When plural treatment rooms are provided in a particle beam treatment facility, in addition to the case where these treatment rooms are arranged in the horizontal direction with respect to the substantially circular extended surface of the accelerator, there are cases where these treatment rooms are arranged in the direction perpendicular to this extended surface. Additionally, the particle beam transport system includes a main line for transporting a particle beam generated by its accelerator to the outside, and further includes a branch line that branched off from the main line to introduce particle beams into the respective treatment rooms. [PTL 1] Japanese Patent No. 4639401 [PTL 2] Japanese Unexamined Patent Application Publication No. H11-176599 In the case of introducing a particle beam into each of the plural treatment rooms arranged at different positions as described above, it is necessary to extend, branch, and bend the particle-beam transport line according to the layout of these treatment rooms. The particle-beam transport line is provided with bending electromagnets and focus electromagnets for controlling the traveling direction of the particle beam. The distribution of the charged particles in the beam passing through the line is not constant, and its cross-sectional shape varies with time because the charged particles oscillate at a constant period called betatron oscillation. For this reason, the particle-beam transport line is required to have a design specification corresponding to the cross-sectional shape of the passing particle beam. Thus, as the line length or the number of branches of the particle-beam transport line increases, the time required for beam line design and field adjustment increases exponentially, resulting in an increase in construction period and cost. Although a cross-sectional shape of a particle beam immediately after being extracted from an accelerator varies depending on the extraction conditions and the beam energy, the particle beam immediately after the extraction has an elliptical cross-sectional shape in most cases. In the case of bending a particle beam that has an elliptical cross-section in a plane including the major axis of the elliptical cross-section, a magnetic field generating Lorentz force is applied from the minor axis direction of the elliptical cross-section. Additionally, in the case of bending this particle beam in a plane including the minor axis of the elliptical cross-section, the magnetic field is applied from the major axis direction of the elliptical cross-section. In this context, a facing interval between a pair of magnetic poles constituting a bending electromagnet is determined on the basis of width of the passing particle beam. In general, the magnetic field strength decreases as the magnetic pole interval increases. Thus, in the case of transporting a particle beam with an elliptical cross-section, specifications of the bending electromagnets configured to efficiently generate a magnetic field and its control specification are different depending on the bending direction, and these specifications are easy to subdivide. This makes designing and manufacturing of equipment and/or field adjustment more complicated for a system having many branches of a particle-beam transport line. In view of the above-described circumstances, an object of embodiments of the present invention is to provide a particle beam transport system that facilitates beamline design, design and manufacture of equipment, field adjustment, and extension and reconstruction so as to contribute to reduction of construction period and cost by making it possible to easily transport a high-quality beam to an arbitrary location in a particle beam treatment facility provided with plural treatment rooms accommodating a particle-beam irradiation equipment and to provide its segment. Hereinafter, a particle beam transport system according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the drawings, the space is represented by a three-dimensional coordinate system in which the u-v plane includes a surface of an accelerator 13 and the direction orthogonal to this u-v plane is defined as the w-direction. Further, the traveling direction of a particle beam is defined as the s-direction, and the respective two directions being orthogonal to the s-direction and being orthogonal to each other are defined as the x-direction and the y-direction. As shown in FIG. 1 to FIG. 3, a particle beam transport system 10 includes focus electromagnets 11 for converging the outer diameter of a passing particle beam by the action of a magnetic field, bending electromagnets 12 for bending the traveling direction of the passing particle beam by the action of a magnetic field, a main line 21 for transporting the particle beam generated by an accelerator 13 to the outside, and a branch line 22 that branches off from the main line 21. At the respective ends of the branch line 22, irradiation equipments 30 (30a to 30e) for irradiating a patient with a particle beam are provided. The main line 21 and the branch line 22 are composed of two or more segments 20 (20a to 20e, 20p, 20q) in which the arrangement of the focus electromagnets 11 and the bending electromagnets 12 is common. Each segment 20 is configured in terms of component arrangement such that each segment 20 can make the particle beam at its segment entrance and the particle beam at its segment exit the same in terms of characteristics. Further, in the particle beam transport system 10, a scatterer 15 for multiple scattering of the passing particle beam is provided at the upstream of the segment 20a nearest to the accelerator 13 such that the cross-section of the particle beam is substantially circular at both ends. A characteristic of the particle beam is physical quantity representing the state of the particle beam, and means, e.g., a betatron function β, an a function, dispersion, change rate of dispersion, and emittance. The main line 21 and the branch line 22 are enclosed continuous spaces having a degree of vacuum sufficient to pass the particle beam. The accelerator 13 is, e.g., a synchrotron, and causes a particle beam, which is generated by accelerating charged particles such as C6+ generated by an ion generating source (not shown) to about 70 to 80% of the light velocity, to be emitted from an exit deflector 14 to the main line 21. A particle beam decreases its speed by losing kinetic energy when passing through a body of a patient, and suddenly stops when falling to a certain speed by receiving a resistance that is approximately inversely proportional to the square of speed. In the vicinity of the stop point of the particle beam, high energy called Bragg peak is emitted. In the particle beam treatment technique, treatment is performed by adjusting this Bragg peak to a lesion tissue of a patient while damage on normal tissues is being reduced. The particle beam emitted from the accelerator 13 has non-uniform distribution of charged particles in a cross-section perpendicular to the traveling direction, and oscillates at a constant period as it is called betatron oscillation. Thus, the particle beam emitted from the accelerator 13 varies in characteristics, and its cross-sectional shape to be observed changes with respect to the beam traveling direction. Since components were designed, manufactured, arranged, and controlled according to the beam characteristics in conventional technology in order to efficiently control the above-described particle beam, there was a problem that specifications and its control became subdivided and field adjustment work became complicated together with an increase in the type of equipment. This problem is solved as described below. As shown in FIG. 4, the cross-sectional shape 42 indicates spread of the beam in the x-y plane that is perpendicular to the traveling direction s of the particle beam 41. The cross-sectional shape 42 can be observed by disposing a screen monitor 43 in the beam traveling direction s and detecting intensity distribution and the like of the beam in the plane. As shown in FIG. 5, each segment 20 includes the focus electromagnets 11, the bending electromagnets 12, a beam-trajectory correction electromagnet (not shown), the screen monitor 43, and a vacuum duct (not shown). In each segment 20, the sequence, placement position, and arrangement angle of its components are determined such that the characteristics and cross-sectional shape of the particle beam are substantially the same at both ends. Further, beam adjustment is performed for each segment 20 by the screen monitor 43 arranged at the most downstream in each segment 20. Each segment 20 shown in the embodiment has a function of bending and transporting the particle beam at an angle of 90° with respect to the traveling direction. In addition, the cross-sectional shape of the particle beam is substantially circular at both ends. Thus, by joining the plural segments 20 to each other, it is possible to easily deflect the trajectory of the particle beam in multiple stages in the horizontal direction and in the vertical direction without newly designing the beam line and without concern for the length of the beam line and the number of branches. In this manner, it is possible to freely transport the particle beam to plural irradiation equipments 30 (30a, 30b, 30c) arranged at the same height level as the accelerator 13 and/or plural irradiation equipments 30 (30d, 30e) arranged at different height levels. In addition, since the constituent components are common to the respective segments, the number of types of components can be reduced, its management is easy, and cost reduction due to mass production effect can be expected. Further, since field adjustment can be performed for each segment, the time required for alignment adjustment and beam adjustment is shortened. Thus, workability is improved not only at initial installation but also at the time of replacing a component due to, e.g., a trouble. In particular, the larger the system becomes in beam line length and in number of branches, the greater this effect becomes. Since each component includes errors such as manufacturing error and installation error, the arrangement and output of the components constituting the segments are finely adjusted for each segment by field adjustment such that the characteristics and cross-sectional shape of the particle beam match the designed values. The segments 20 constitute a part or all of the main line 21 and the branch line 22. Although only one arrangement pattern for the segments 20 is shown in the embodiment, the particle beam transport system 10 may be configured by using plural arrangement patterns of segments in combination. For instance, by combining segments having a function of bending and transporting a particle beam at an angle of 45° with respect to the traveling direction, it is also possible to irradiate a patient with a particle beam from an obliquely upward direction instead of from the vertical direction. Next, a method of controlling the cross-sectional shape of the particle beam will be described. The bending electromagnets 12 can make the beam trajectory into an arc shape by bending the traveling direction of the passing particle beam under the action of a magnetic field. The particle beam passing through the bending electromagnets 12 is caused to go straight in a tangential direction. As shown in FIG. 7, each focus electromagnet 11 includes a substantially ring-shaped yoke 51, four magnetic cores 52 integrally projected inwardly from the yoke 51 at equal angular intervals, and exciting coils 53 individually wound around the four magnetic cores 52. In the gap inside the yoke 51, magnetic fields indicated by the solid arrows are generated. Although a quadrupole electromagnet is exemplified as the focus electromagnets 11 in the embodiment, the configuration is not limited to such an aspect. For the charged particle beam to be transported, Lorentz force in the inner direction acts on the charged particle located at q1 on the x-axis and Lorentz force in the outer direction acts on the charged particle located at q2 on the y-axis. That is, each focus electromagnet 11 focuses the particle beam in the x-axis direction and defocuses the particle beam in the y-axis direction. Intensity of focusing/defocusing a beam can be controlled by intensity of direct current applied to the exciting coils 53. In addition, it is possible to reverse the focus direction and defocus direction of the beam by reversing the direction of the direct current applied to the excitation coils 53, because the direction of each magnetic field to be formed is reversed by reversing the direction of the direct current. Since the plural focus electromagnets 11 in the embodiment are configured by alternately arranging the one for focusing the beam in the x-direction and the one for focusing the beam in the y-direction, the plural focus electromagnets 11 adjust the beam diameter to a desired value by controlling the direct current applied to each electromagnet 11 and sequentially adjusting balance between focusing and defocusing in the x-direction and the y-direction. The graph of FIG. 6 illustrates a case where the focus electromagnets 11 and the bending electromagnets 12 constituting one segment 20 are developed on a straight line and the betatron function β of the particle beam at the position s of this segment 20 is divided into two directions (i.e., x-direction and y-direction) orthogonal to each other. The betatron function β is a parameter related to the outer diameter of the particle beam. In order to avoid collision with the particle beam, there is a close relationship between the facing interval of a pair of magnetic poles constituting the bending electromagnet and the outer diameter of the beam. In order to efficiently generate a magnetic field without widening the interval between the magnetic poles, the betatron function β is suppressed to as small as 100 m or less. In each segment 20 of the present embodiment, arrangement conditions of respective components including arrangement order, placement positions, and arrangement angles are determined in such a manner that the betatron function β (βx, βy) in the orthogonal direction (x, y) of the passing particle beam is equal at the upstream end and the downstream end. In the present embodiment, the first bending electromagnet 12, the quadrupole electromagnet 11, and the second bending electromagnet 12 are symmetrically arranged in this order so as not to change the dispersion before and after the deflection, and two quadrupole electromagnets 11 for controlling the betatron functions in the x-direction and the y-direction are arranged at each of its upstream side and downstream side. This component arrangement can be variously modified according to each embodiment. For instance, when three quadrupole electromagnets are used, control of the betatron function becomes easy and it is possible to realize wide beam energy width. In addition, by arbitrarily arranging beam trajectory correction electromagnets upstream and downstream, it is possible to finely adjust the beam axis according to the local environment on a segment basis. Additionally or alternatively, by arranging a screen monitor at the most upstream and/or the most downstream, beam behavior in each segment can be grasped in detail. Since energy of a transport beam differs depending on depth of an irradiation target, the optimum current value corresponding to the energy of the transport beam is preset for each electromagnet. In this case, the current values of the respective electromagnets in each segment are adjusted to each other in such a manner that the beam parameters such as the betatron function, dispersion and its change rate are equal at the upstream end and the downstream end. In other words, each segment 20 is configured such that the characteristics and cross-sectional shape of the particle beam are substantially the same at both ends. In the above-described case, by setting the phase difference between the upstream end and the downstream end to be an integral multiple of 180 degrees, the phase at the end of the irradiation equipment can always be kept constant regardless of the number of segments. It may be set to have a predetermined phase at the end of the irradiation equipment as a result of combining plural segments, but the degree of freedom of placement is reduced in such a case. Returning to FIG. 1, the description of configuration of the particle beam transport system 10 is continued. The scatterer 15 is provided further upstream of the segment 20a that is closest to the accelerator 13. Although a thin plate of aluminum is used for the scatterer 15 in the present embodiment, another material can be appropriately used for the scatterer 15 as long as it is a material that causes multiple scattering of a passing particle beam such as an acrylic plate. When a particle beam collides with this scatterer 15, the particles are scattered with a certain scattering angle depending on the material and the thickness of the scatterer 15. Before and after scattering, the position and momentum of the particles change. When the scatterer is sufficiently thin, the positional change is small and negligible, and it can be approximated that only the momentum varies before and after scattering. In the present embodiment, the respective emittances in the orthogonal directions x and y of the particle beam are made uniform after scattering, and material and thickness of the scatterer 15 are set such that anisotropy of emittance is eliminated in the orthogonal directions (x, y) of the particle beam. Furthermore, by eliminating the anisotropy of the betatron function in the orthogonal directions (x, y) of the particle beam, it is possible to obtain beam characteristics in which the cross-sectional shape is substantially circular. Additionally, taking notice to the distribution of the charged particles, it is also possible to align the distribution of the particle beam in the orthogonal directions (x, y) to the Gaussian distribution and eliminate non-uniformity. Thereby, it is possible to introduce a particle beam having uniform characteristics and a substantially circular cross-sectional shape at the upstream end of the segment 20a located at the most upstream and to freely transport particle beams to different height levels depending on the subsequent segment. As shown in FIG. 8, the gantry-type irradiation equipment 30 includes a gantry 32, a beam transport system 33, an irradiation nozzle 34, and a movement controller 37. The gantry 32 has a treatment space 38 therein, and is rotationally displaced about its rotation axis 31 by its rotation driver (not shown). The beam transport system 33 is fixed to the gantry 32, and is rotatably provided at the end of the branch line 22 (FIG. 3) via a joint 39. The irradiation nozzle 34 irradiates the treatment space 38 with the particle beam 41 transported by the beam transport system 33 from the radial direction of the gantry 32. The movement controller 37 moves the bed 36 on which the patient 35 is placed, and sets the position and direction in the treatment space 38. Since the irradiation equipment 30 is configured as described above, it is possible to bend the trajectory of the particle beam 41 inputted along the rotation axis 31 of the gantry 32 by 90° and to irradiate the patient 35 with this particle beam 41 from an arbitrary direction orthogonal to the rotation axis 31. According to the present embodiment, since there is no anisotropy in the characteristics in the orthogonal directions (x, y) of the particle beam passing through the end of each segment 20 connected to the joint 39 and the cross-sectional shape of the particle beam is substantially circular, a constant beam quality is maintained independently of the rotation of the gantry 32. Although a description has been given of the case where all of the plural irradiation equipments 30 to be disposed are the gantry-type in the present embodiment, all or some of the irradiation equipments 30 may be replaced by the fixed-type irradiation equipments. Since the characteristics and cross-sectional shape of the particle beam are substantially the same at both ends of each segment 20, there are compatible points between the gantry-type and the fixed-type. Thus, in the case of arranging the irradiation equipments 30 at the respective ends of the segments 20, there is no need to newly design a beam line and the degree of freedom of arrangement increases. Likewise, in the case of extension and reconstruction such as extension of a beam line or installing a new irradiation equipment, by newly arranging an additional segment 20 and an additional irradiation equipment 30 at the terminal of the segments 20, there is no need to newly design a beam line and it is possible to easily realize the extension and reconstruction with shorter construction period and lower cost. According to the particle beam transport system of at least one embodiment as described above, since the characteristics and cross-sectional shape of the particle beam are substantially the same at both ends of each of the plural segments, it is possible to easily transport a high-quality beam to an arbitrary place. Hence, it is possible to facilitate beamline design of a particle beam treatment facility provided with plural treatment rooms accommodating irradiation equipments and to facilitate design and manufacture of the equipment, field adjustment, and extension and reconstruction of this facility, and thus it is possible to shorten its construction period and to reduce its construction cost. Whereas a few embodiments of the present invention have been described, these embodiments are presented only by way of example, and not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, changes, and combinations can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the spirit and scope of the invention as well as in the invention set forth in the appended claims and the scope of equivalents thereof. |
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claims | 1. A method of protecting a stud extending from a nuclear reactor pressure vessel (RPV) flange, comprising the steps of: removing a fastener nut and washer from a threadedly engaged stud extending from a RFV flange through a stud hole of a flange of a removable RPV head supported on the RPV flange; placing a stud enclosure over the stud and into physical contact with the RPV flange while the RPV head is supported on the RPV, the stud enclosure having an internal portion; fastening the stud enclosure to the stud; and pressurizing the internal portion of the stud enclosure with a gas to above atmospheric pressure. 2. The method of claim 1 , wherein the step of fastening the stud enclosure to the stud urges the stud enclosure into sealing contact with the RPV flange. claim 1 3. The method of claim 1 , wherein the step of pressuring the internal portion of the stud enclosure with a gas comprises: pressurizing the stud enclosure with air. claim 1 4. The method of claim 1 , wherein the step of pressurizing the internal portion of the stud enclosure with a gas comprises: pressurizing the stud enclosure to a pressure of 10 psi. claim 1 5. The method of claim 1 , wherein the step of pressurizing the internal portion of the stud enclosure with a gas comprises: pressurizing the stud enclosure to a pressure of more than 10 psi. claim 1 6. The method of claim 1 , wherein the stud has an upper end, the stud enclosure has a capped end and the step of fastening the stud enclosure to the stud comprises: fastening the capped end of the stud enclosure to the upper end of the stud. claim 1 |
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summary | ||
abstract | A nuclear fission reactor, flow control assembly, methods therefor and a flow control assembly system. The flow control assembly is coupled to a nuclear fission module capable of producing a traveling burn wave at a location relative to the nuclear fission module. The flow control assembly controls flow of a fluid in response to the location relative to the nuclear fission module. The flow control assembly comprises a flow regulator subassembly configured to be operated according to an operating parameter associated with the nuclear fission module. In addition, the flow regulator subassembly is reconfigurable according to a predetermined input to the flow regulator subassembly. Moreover, the flow control assembly comprises a carriage subassembly coupled to the flow regulator subassembly for adjusting the flow regulator subassembly to vary fluid flow into the nuclear fission module. |
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041742931 | summary | In recent years there has been a large scale increase in the number of water-cooled nuclear reactors both in the United States and abroad. This has created a large problem in that such reactors create large quantities of radioactive solutions of aqueous wastes. The water molecules contained in such wastes often contain the element tritium which in and of itself poses environmental hazards. Further, such aqueous waste solutions may contain radioactive isotopes of elements such as cesium, iodine, and the like, which have relatively low vaporization temperatures. Safety requires that such wastes be stored in leak-proof containers over long periods of time to prevent damage to the environment. Due to the large volume of such wastes, disposal methods must be economical if nuclear power is to survive in competition with fossil fuel plants. In British Pat. No. 938,211, issued to Rudolph Albert on Oct.2, 1963, entitled "Improvements in Methods of Solidifying Watery Atomic Waste", there is disclosed a process whereby aqueous solutions of atomic waste waters are used as the water, for the hydration of a mixture of alumina cement with or without aggregate added thereto; the water-cement mixture is thereafter allowed to set up, and is later baked at a temperature of about 1200.degree. C. for several hours, allowed to cool and thereafter impregnated with plastics, paraffin and/or other materials to reduce the possibility of the radioactive wastes entrained therein from leaking out. The temperatures employed in this process boils off excess water from the concrete mixture and will cause many of the radioactive elements contained therein to vaporize, thus requiring apparatus to prevent such vapors from reaching the atmosphere. This thermal requirement greatly increases the cost of the process and reduces the production rate of the plant. It is an object of this invention to provide an efficient, economical process for incorporating aqueous solutions containing radioactive elements at temperatures below 99.degree. C., into a solid substantially non-compressible, non-leachable body. SUMMARY OF THE INVENTION A process for disposing of aqueous solutions containing radioactive wastes whereby the waste solution is dispersed in situ throughout a mass of powdered portland cement, said cement being placed in a leakproof container and is densified tnerein to a bulk density ranging from about 1.3 to about 1.8 grams per cubic centimeter and a practice size ranging from about 120 mesh to about 400 mesh; the amount of water dispersed in the powdered cement being in a weight ratio thereto of from about 15 weight percent to about 30 weight percent based upon the weight of the powdered cement so used; sealing the container containing the cement with the aqueous solution dispersed therein to prevent evaporation of the aqueous solution contained therein during cement curing, thereafter impregnating the cured cement in said container with a mixture of a monomer and polymerization catalyst and polymerizing the monomer impregnated in said mixture in situ within the cured cement body, thereafter storing the container containing the polymer-impregnated cement in a storage facility suitable for storing such containers. Throughout the process the temperature of the cement body containing the aqueous solution containing the radioactive waste material is maintained at a temperature below 99.degree. C. In the preferred embodiment of this invention, we maintain the cement-aqueous solution mix at a temperature below 90.degree. C. throughout the processing. While cooling mechanisms can be employed if it is desired to make very large bodies of cement in accordance with this process, none are needed when the body is formed within conventional 55 gallon industrial drums and type II portland cement is used. No mixing apparatus is required to work the mixture of cement and aqueous solution but rather the water is dispersed in situ within a quiescent body of the densified powdered cement in the container through porous tubes strategically placed throughout the powdered cement. These tubes may be left in the cement after processing. The impregnation of the concrete with monomer and catalyst is accomplished simply by covering the entire surface of the cured cement within the container with a mixture of monomer and polymerization catalyst and allowing the monomer-catalyst solution to seep down thru and completely impregnate the concrete body in the container. |
claims | 1. A Boiling Water Reactor (BWR) jet pump inlet mixer compliant stop, comprising:a main body with a first longitudinal length in a first direction, the main body including opposing front and rear surfaces running along the first longitudinal length of the main body;a foot extending longitudinally along the rear surface of the main body;a spring attached to the main body and projecting beyond the front surface of the main body in a second direction that is about perpendicular to the first longitudinal length of the main body; andat least one jacking bolt connecting the main body to the foot, a second longitudinal length of the at least one jacking bolt being about parallel to the second direction, wherein the at least one jacking bolt is configured to be tightened to compress the spring to cause the spring to impart a controlled lateral force in the second direction during installation of the compliant stop between two stationary opposing surfaces. 2. The compliant stop of claim 1, wherein,the spring is located near a mid-section of the main body,the at least one jacking bolt includes a first jacking bolt and a second jacking bolt, the first and second jacking bolts are located on either side of the spring. 3. The compliant stop of claim 2, whereina front surface of the foot defines a first and second jacking bolt retention hole configured to retain a distal end of a jacking bolt; anda first and second threaded hole in the main body, each threaded hole configured to engage threads on each jacking bolt to cause the main body to separate from the foot as the jacking bolts are tightened. 4. The compliant stop of claim 3, further comprising:a first protruding boss on the front surface of the main body; anda second protruding boss on an inner surface of a distal end of the spring, the first and second protruding bosses directly opposing each other to define a gap between the bosses. 5. The compliant stop of claim 3, further comprising:a concave spherical seat on an outer surface of a distal end of the spring;a swivel contact pad with a concave cylindrical outer surface, the swivel contact pad having an inner convex spherical face configured to mate with the concave spherical seat; andself-alignment ribs extending from the inner convex spherical face of the swivel contact pad, the self-alignment ribs insertable into alignment channels on the outer surface of the distal end of the spring. 6. The compliant stop of claim 3, further comprising:a first and second bolt keeper attached to the front surface of the foot, each bolt keeper located near a respective jacking bolt retention hole,wherein each bolt keeper is configured to contact an edge of the respective jacking bolt to allow the distal end of the jacking bolt to freely rotate within the jacking bolt retention hole. 7. The compliant stop of claim 3, further comprising:a ratchet keeper with two ends, the ratchet keeper attached longitudinally across a top surface of the foot;ratchet teeth on each end of the ratchet keeper; anda first and second ratchet tooth slot located in the foot and above each jacking bolt retention hole,wherein each ratchet tooth slot is configured to accept respective ratchet teeth of the ratchet keeper, allowing the ratchet teeth to contact a respective jacking bolt to lock the respective jacking bolt into a desired position within the foot. 8. The compliant stop of claim 3, further comprising:a c-clamp on each of two lateral sides of the foot and the main body, each c-clamp including,a c-clamp frame with a vertical downwardly projecting overhang, the overhang having a sloped face configured to mate with sloped faces on the two lateral sides of the foot and the main body,a c-clamp body with a vertical upwardly projecting upward portion, the c-clamp body configured to slide in and out of the c-clamp frame,a cap screw configured to lock the c-clamp body into a desired position within the c-clamp frame. 9. The compliant stop of claim 3, further comprising:a spherical shaped backstop at an end of the first jacking bolt retention hole, the spherical shape of the backstop capable of mating with a shape of the distal end of the first jacking bolt;a flat shaped backstop at an end of the second jacking bolt retention hole; anda pad located at the end of the second jacking bolt retention hole, the pad having a first and a second side, the first side being flat and the second side being spherical in shape, the spherical shape of the second side capable of mating with a shape of the distal end of the second jacking bolt,wherein a diameter of the pad is smaller than a diameter of the second jacking bolt retention hole. 10. The compliant stop of claim 2, wherein the spring is made from a material that experiences less thermal expansion than materials used to make the main body, the foot and the jacking bolts. 11. The compliant stop of claim 4, wherein the compliant stop is configured to allow the at least one jacking bolt to be tightened to force the main body and the foot to separate while causing the gap between the first and second protruding bosses to decrease during installation of the compliant stop. |
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048067679 | abstract | An electron lens assembly comprises at least a pair of magnetic pole pieces disposed in opposition to each other and each having a bore allowing an electron beam to pass therethrough, an exciting coil for producing a magnetic field between the magnetic pole pieces, a yoke coupled to the magnetic pole pieces and constituted by two divided yoke members so that the exciting coil can be accommodated, at least one of the two yoke members being detachably coupled to one of the magnetic pole pieces, and a pipe disposed along the electron beam path for defining a passage for the electron beam except for a space formed between the magnetic pole pieces. A metal O-ring is disposed on a surface of the detachable yoke member so as to prevent the air from entering the space defined between the opposite magnetic pole pieces along the surface of the detachable yoke member from a space accommodating the exciting coil. The electron beam passage defining pipe is coupled integrally to the detachable yoke member. With the electron lens structure, an ultra-high vacuum can be sustained within the column. |
description | The disclosed and claimed concept relates generally to nuclear power generation equipment and, more particularly, to a rotation apparatus usable in conjunction with a control drum that is employed in a nuclear environment. Numerous types of nuclear fission reactors are known in the relevant art. As a general matter, such nuclear reactors include a reactor vessel within which is situated an amount of fissile material and a number of control structures that control the reactivity of the nuclear fission reaction. In certain types of nuclear reactors, control rods are provided as the control structures. Such control rods are received by varying, distances into the fissile material wherein the rods function as absorber devices that progressively reduce the reactivity of the fission reaction as the rods are received into the fissile material. Another type of control structure is a control drum that is of an approximately cylindrical shape and which is situated on a pivotable shaft. The control drum includes a reflector portion and an absorber portion. The shaft is rotatable about an axis of rotation to cause the reflector portion to face toward a core of the nuclear environment in an operational state of the nuclear environment. The shaft is rotated about the axis of rotation to cause the absorber portion to face toward the core to result in a shutdown condition of the reactor. For instance, the reflector portion reflects neutrons back to the core in the operational state, and the reflector portion absorbs neutrons in the shutdown state. While control drums of this type have been generally effective for their intended purposes, they have not been without limitation. Such control drums are typically rotated by stepper motors which require electrical power in order to operate. In a situation in which an emergency shutdown of the reactor is desired, an absence of electrical power to operate the stepper motors to move the control drums to the shutdown positions could potentially result in a catastrophic situation. Furthermore, in the event that the nuclear environment is capable of being physically transported from one location to another, it is desirable to ensure that the absorber portion of the control drum faces toward the core in order to avoid a possible unintended startup of the reactor. Such an unintended startup of the reactor potentially could occur if the reflector portion of the control drum were inadvertently repositioned to be fully or partially facing toward the core. While the stepper motors that control the control drums typically can maintain an orientation of the control drum such that the reflector portion faces away from the core, such control potentially can be lost if any such stepper motor loses electrical power, and the transporting of the nuclear environment from one location to another raises a significant potential of a loss of electrical power. Improvements thus would be desirable. An improved rotation apparatus is usable with a control drum in a nuclear environment. The control drum is situated on a shaft that is rotatable about a horizontal axis of rotation, and the control drum includes an absorber portion and a reflector portion. The rotation apparatus includes a rotation mechanism that is structured to apply to the shaft in an operational position a force that biases the shaft to rotate toward a shutdown, position, with the force being resisted by a motor to retain the shaft in the operational position when the motor is powered. The force is not resisted when the motor is unpowered. The rotation apparatus further includes a rotation management system that controls the rotation of the shaft. Accordingly, an aspect of the disclosed and claimed concept is to provide a rotation apparatus that is operable in the event of an electrical power failure to move a control drum from an operational position to a shutdown position. Another aspect of the disclosed and claimed concept is to provide such a rotation apparatus that rapidly moves the control drum to the shutdown position in the absence, of electrical power. Another aspect of the disclosed and claimed concept is to provide such a rotation apparatus that additionally can retain the control drum in the shutdown position when the nuclear environment is being transported from one location to another and in the absence of electrical power in such a situation. Accordingly, an aspect of the disclosed and claimed concept is to provide an improved rotation apparatus usable with a control drum in a nuclear environment, the control drum having a shaft that is rotatable about an axis of rotation that is horizontal, a reflector portion situated on the shaft, an absorber portion situated on the shaft, and a motor which, when powered, is operable to move the shaft between an operational position wherein the reflector portion faces toward a core of the nuclear environment and a shutdown position wherein the absorber portion faces toward the core. The rotation apparatus can be generally stated as including a rotation mechanism which is structured to apply to the shaft in the operational position a force that is structured to rotate the shaft toward the shutdown position, the force being resisted by the motor to retain the shaft in the operational position when the motor is powered, the force not being resisted when the motor s unpowered, and a rotation management system that is structured to resist rotation of the shaft when the shaft is in the shutdown position. Other aspects of the disclosed and claimed concept are provided by an improved rotation management system that is usable with a control drum in a nuclear environment, the control drum having a shaft that is rotatable about an axis of rotation that is horizontal, a reflector portion situated on the shaft, an absorber portion situated on the shaft, and a motor which, when powered, is operable to move the shaft between an operational position wherein the reflector portion faces toward a core of the nuclear environment and a shutdown position wherein the absorber portion faces toward the core. The rotation management system can be generally stated as including an actuator, a bolt that is situated on the actuator, and the actuator being operable to move the bolt between a first location engaged with, the shaft in the shutdown position and a second location disengaged from the shaft, the bolt in the first position being structured to resist rotation of the shaft. Similar numerals refer to similar parts throughout the specification. An improved rotation apparatus 4 in accordance with a first embodiment of the disclosed and claimed concept is depicted in FIGS. 1 and 2 as being a part of an improved drum control apparatus 6. The control drum apparatus 6 is a part of a nuclear environment 8 such as might include a nuclear reactor, a nuclear power plant, by way of example and without limitation. As can be understood from FIGS. 1 and 2, the control drum apparatus 6 can be said to include, in addition to the rotation apparatus 4, a control drum 10, and a shaft 12 upon which the control drum 10 is situated. The nuclear environment 8 includes a support 14 upon which the shaft 12 is rotatably disposed. The control drum 10 can be said to include a reflector portion 16 that is configured to reflect neutrons in the nuclear environment 8 and an absorber portion 18 that is configured to absorb neutrons in the nuclear environment 8. The shaft 12 is rotatable about an axis of rotation 20 by operation of a stepper motor 24 that is connected between the support 14 and the shaft 12. The stepper motor 24 is electrically operable to rotate the shaft 12 and the control drum 10 situated thereon between an operational position, such as is depicted generally in FIG. 1, and a shutdown position, such as is depicted generally in FIG. 2. In the operational position of FIG. 1, the reflector portion 16 faces generally toward a core 22 of the nuclear environment 8 and thereby enhances the reactivity of the fission reaction in the core 22. In the shutdown position of FIG. 2, the absorber portion 18 faces generally toward the core 22 and absorbs neutrons to reduce the reactivity of the fission reaction. The control drum apparatus 6 includes the aforementioned stepper motor 24 and further includes an encoder 27 that is connected with the stepper motor 24 or the shaft 12 and which outputs a series of pulses that are representative of rotational movement of the shaft 12 about the axis of rotation 20. The pulses are detected by a control system of the control drum apparatus 6 in order to continually ascertain the rotational position of the control drum 10 with respect to the core 22 and/or with respect to other structures. In the depicted exemplary embodiment, the axis of rotation 20 is oriented along the horizontal direction, such as is indicated at the numeral 26. It is understood that the horizontal direction 26 is perpendicular to the vertical direction, such as is indicated at the numeral 28. The rotation apparatus 4 can be said to include a rotation mechanism 30 and a rotation management system 32. As will be set forth in greater detail below, the rotation mechanism 30 applies a force to the shaft 12 in the operational position to bias the shaft toward the shutdown position. The force is resisted by the stepper motor 24 when the stepper motor 24 is energized. When the stepper motor 24 is de-energized, such as in the event of a failure of electrical power to the stepper motor 24, the force that is applied by the rotation mechanism 30 to the shaft 12 is no longer resisted by the stepper motor 24, and the force thus rotates the shaft 12 from the operational position of FIG. 1 toward the shutdown position of FIG. 2. While the word “force” has been used herein, it is understood that such force is being applied to the shaft 12 which is rotatable, and thus it is understood that the word “force” can be used interchangeably with the word “torque” in the context of the rotatable shaft 12 inasmuch as the force is being applied at a distance from the axis of rotation 20, which will result in a torque being applied to the shaft 12. As will be set forth in greater detail below, the rotation management system 32 can be said to include a rotation initiator 34, an eddy current brake 36, and a lock 38. As will likewise be set forth in greater detail below, the rotation initiator 34 initiates rotational movement of the shaft 12 away from the operational position that is depicted generally in FIGS. 1, 3, and 5. The eddy current brake 36 controls the rotational velocity of the shaft 12 as the shaft 12 is approaching the shutdown position. The lock 38 resists rotation of the shaft 12 away from the shutdown position. As can, be understood from FIGS. 1-4, the rotation mechanism 30 can be said to include a weight 40 having a center of gravity 42 that is spaced from the axis of rotation 20. The weight 40 is affixed to the shaft 12 and thus moves with the shaft 12 between the operational and shutdown positions. Inasmuch as the center of gravity 42 is spaced from the axis of rotation 20, the weight 40 can be referred to as a counterweight that applies a torque to the shaft 12 by operation of gravity depending upon the position of the center of gravity 42 with respect to the axis of rotation 20. For instance, when the center of gravity 42 is situated directly vertically above the axis of rotation 20, such as is depicted in FIGS. 1 and 3, which is when the shaft 12 is in the operational position, the weight 40 at most merely applies a vertically downward force on the shaft 12 without applying a torque to the shaft 12. In such condition, the weight 40 can be said to be situated in a state of equipoise above the axis of rotation 20. However, when the center of gravity 42 is anywhere other than situated directly vertically above the axis of rotation 20, the distance along the horizontal direction 26 between the axis of rotation 20 and the center of gravity 42 is the distance from the axis of rotation 20 at which the weight 40 is applied to the shaft 12 to result in a torque being, applied to the shaft 12. The rotation initiator 34 thus provides an initial rotation of the shaft 12 away from the operational position of FIGS. 1 and 3 to initiate rotation of the shaft 12 from the operational position toward the shutdown position in the event that a shutdown is needed when the stepper motor 24 is in an unpowered condition. More specifically, and as can be understood from FIGS. 3 and 4, the rotation initiator 34 includes a pair of permanent magnets that are indicated at the numerals 44A and 44B, and which may be collectively or individually referred to herein with the numeral 44. The permanent magnets 44 each include a north pole 46 and a south pole 48 on opposite sides thereof. The permanent magnet 44A is situated on a strut 50 that is disposed on the support 14, and the permanent magnet 44B is situated in a receptacle 52 that is formed on the weight 40. The permanent magnets 44 have their north and south poles 46 and 48 arranged such that they mutually oppose one another when the shaft 12 is in the operational position of FIG. 3. In this regard, it can be said that the weight 40 is in a first position when the shaft 12 is in its operational position, as is depicted generally in FIG. 3, and the weight 40 can be further said to be in a second position when the shaft 12 is in the shutdown position, such as is depicted generally in FIG. 4. In order to avoid the permanent magnets 44 from themselves creating a condition wherein the permanent magnets 44 with their mutual magnetic repulsion are in a state of equipoise, the permanent magnets 44A and 44B are actually slightly offset from one another and not in a state of equipoise when the shaft 12 is in the operational position. The result is that the permanent magnets 44 apply to the shaft 12 another torque that biases the shaft 12 toward the shutdown position but which is overcome by the stepper motor 24 while the stepper motor 24 is electrically energized. The offsetting between the permanent magnets 44A and 44B is on the order of approximately 5-8 rotational degrees of the shaft 12, meaning that the permanent magnets are positioned such that they would directly oppose one another if the shaft 12 were rotated 5-8 rotational degrees, as the case may be, from the operational position. When the shaft 12 is in its operational position and the weight 40 is in its first position, such as is depicted generally in FIGS. 1 and 3, the permanent magnets 44 are already offset from one another by approximately 5-8 rotational degrees such that a loss of electrical power to the stepper motor 24 will immediately result in the mutual opposition of the magnets rotating the shaft 12 beyond the initial 5-8 rotational degree offset toward the shutdown position. As can be understood from FIGS. 1-4, the center of gravity 42 of the weight 40 is higher in the vertical direction 28 in the first position of FIGS. 1 and 3 than it is in its second position of FIGS. 2 and 4. Since the shaft 12 is oriented parallel with the horizontal direction 26, the weight 40 in the first position has a greater potential energy than in the second position, and such relatively greater potential energy is employed in rotating the shaft 12 with the control drum 10 thereon from the operational position to the shutdown position. When the weight 40 is in the exemplary second position of FIGS. 2 and 4, the center of gravity 42 is situated vertically below the axis of rotation 20, meaning that the center of gravity 42 in the second position and the center of gravity 22 are aligned with one another along the vertical direction 28. It thus can be seen that the stepper motor 24, when energized, resists the bias of the mutual opposition of the permanent magnets 44 when the weight 40 is in the first position, and this retains the shaft 12 in the operational position. Should the stepper motor 24 become unpowered, however, the bias that is provided by the permanent magnets 44 initiates rotation of the shaft 12 to move the weight 40 from the first position toward the second position. As soon as the center of gravity 42 is offset along the horizontal direction 26 from the axis of rotation 20, gravity being applied to the weight 40 causes the shaft 12 to continue to rotate to the second position of the weight 40, which is the shutdown position of the shaft 12. As such, gravity acting on the weight 40 causes the shaft 12 to be rotated to the shutdown position in the absence of electrical power being applied to the stepper motor 24. It is noted, however, that the need for a shutdown can sometimes be on an urgent basis, in which situation it would be desired to position the shaft 12 in the shutdown position of FIG. 2 as quickly as possible. Such repositioning to the shutdown position would desirably be without the shaft 12, for instance, rotating beyond the shutdown position and the oscillating back and forth across the shutdown position until the shaft finally settles in the shutdown position. As such, the eddy current brake 36 is provided in order to manage the rotational velocity of the shaft 12 as it approaches the shutdown position. More specifically, the eddy current brake 36 includes a pair of permanent magnets that are indicted at the numerals 54A and 54B, and which may be collectively or individually referred to herein with the numeral 54. The permanent magnets 54 each include a north pole 56 and a south pole 58, and the permanent magnets 54 are arranged on the support 14 such that one of the north poles 56 faces toward one of the south poles 58 whereby the permanent magnets 54 can be said to mutually attract one another. The eddy current brake 36 further includes a flywheel 60 that is situated on the shaft 12 and which rotates therewith. The flywheel 60 is formed of an electrically conductive material such as aluminum, copper, steel, or other appropriate material. The flywheel 60 has a number of notches 62 formed therein to form a number of radially-oriented fins 64 situated between the notches and a solid portion 66 that is free of notches 62. As employed herein, the expression “a number of” and variations thereof shall refer broadly to any non-zero quantity, including a quantity of one. When the weight 40 is in the first position of FIG. 3, some of the fins 64 are situated between the permanent magnets 54, and the solid portion 66 is spaced in the vertical direction 28 above the space between the permanent magnets 54. As the shaft 12 begins to rotate from the operational position of FIG. 3 toward the shutdown position of FIG. 4, a subset of the fins 64 successively travel through the space between the permanent magnets 54. When the solid portion 66 begins to travel between the permanent magnets 54, eddy currents are induced in the solid portion 66 by the magnetic field of the permanent magnets 54, it being reiterated that the north and south poles 56 and 58 are arranged such that they mutually attract. According to Lenz's Law, the eddy currents that are induced in the solid portion 66 will create their own magnetic fields which oppose the field of the permanent magnets 54, with such magnetic opposition slowing the rotational velocity of the shaft 12. The aforementioned eddy currents are not induced to a meaningful extent in the fins 64 since they are relatively small along the circumferential direction in comparison with the solid portion 66. The braking of the shaft 12 by the rotationally-moving reception of the solid portion 66 between the permanent magnets 54 has the effect of slowing the rotation of the shaft 12 to enable the shaft 12 to be positioned such that the center of gravity 42 of the weight 40 is at its vertically lowest possible position. That is, the braking force that is applied to the solid portion 66 by the eddy current brake 36 is directly dependent upon the rotational velocity of the shaft 12 and of the solid portion 66 affixed thereto. As the rotational velocity of the shaft 12 is slowed, the magnetic braking force is correspondingly reduced, and the weight 40 is permitted to move to a position wherein the center of gravity 42 is situated vertically below the axis of rotation 20 without the weight 40 moving past such position and then oscillating back and forth with respect to such position until the weight 40 naturally reaches its lowest point. Rather, since the permanent magnets 54 slow the solid portion 66 by applying a magnetic braking force that is based upon the velocity of the solid portion 66, movement of the solid portion 66 is essentially slowed to the point that the effect of gravity on the weight 40 holds it so that the center of gravity 42 is at its lowest possible position without having moved past its lowest possible position. This rapidly moves the shaft 12 from its operational position to its shutdown position without oscillating back and forth around the shutdown position. This results in a rapid shutdown of the nuclear environment 8, which is desirable. As further noted above, the rotation management system 32 additionally includes the lock 38 that is depicted generally in FIGS. 1-2 and 5-6. The lock 38 includes a bolt 68 which can be said to constitute a first portion, of the lock 38 and further includes a receptacle 70 that is formed on the shaft 12 and that can be said to constitute a second portion of the lock 38. The lock 38 further includes an actuator 72 that is in the form of a linear actuator and that is situated on the support 14. The linear actuator is operable to move the bolt 68 between a first location, such as is depicted generally in FIG. 6, which corresponds with a locked position of the lock 38, and a second location, such as is depicted generally in FIG. 5, and which corresponds with an unlocked position of the lock 38. The actuator 72 is electrically powered, but the bolt 68 does not move between the first and second locations unless the actuator 72 is energized. As such, when it is desired to place the shaft 12 in a locked configuration, the shaft 12 is rotated to its shutdown position, and the actuator 72 is energized to linearly move the bolt 68 from the second location of FIG. 5 to the first location of FIG. 6, in which situation the bolt 68 is received in the receptacle 70. The bolt 68 being received in the receptacle 70 resists movement of the shaft 12 away from the shutdown position. The bolt 68 remains in the first location regardless of whether the actuator 72 is electrically powered or is electrically unpowered. The shaft 12 can thus remain in a locked configuration during transport of the nuclear environment 8, by way of example, whether or not the actuator 72 is electrically energized. When the shaft is desired to be unlocked, the actuator 72 is energized to return the bolt 68 from the first position of FIG. 6 to the second position of FIG. 5, and the stepper motor 24 can be energized to rotate the shaft 12 from the shutdown position of FIG. 6 to the operational position of FIG. 5. It thus can be understood that the rotation apparatus 4 can cause the control drum apparatus 6 to rotate from the operational position to the shutdown position in the event of an electrical power loss to the stepper motor 24. Furthermore, the lock 38 retains the shaft 12 in the locked position of FIG. 6 regardless of whether the actuator 72 continues to be electrically energized after having moved the bolts 68 to the first location of FIG. 6. This combination of features advantageously permits the nuclear environment 8 to be rapidly shut down as needed, even in the event of a failure of electrical power to the stepper motor 24, and the nuclear environment 8 is retained in the shutdown position by virtue of the lock 38 regardless of whether electrical power is available to the actuator 72. Other benefits will be apparent. An improved control drum apparatus 106 is depicted in FIG. 7 and is depicted in part in FIGS. 8-11. The control drum apparatus 106 includes an improved rotation apparatus 104 in accordance with a second embodiment of the disclosed and claimed concept. The control drum apparatus 106 is similar to the control drum apparatus 6 in that it includes a control drum 110 situated on a shaft 112 that is rotatably disposed on support 114, with the control drum 110 including a reflector portion 116 and an absorber portion 118, and with the shaft 112 being rotatable about an axis of rotation 120 by operation of a stepper motor 124. The rotation apparatus 104 is different from the rotation apparatus 4 in that it includes a rotation mechanism 130 and a rotation management system 132 that are different than the rotation mechanism 30 and the rotation management system 32. More specifically, the rotation mechanism 130 includes a spring 133 that extends between the support 114 and the shaft 112 and which, in the operational position of FIG. 8, is elastically deflected such that the spring 133 biases the shaft 112 from the operational position of FIG. 8 toward the shutdown position of FIG. 9. The stepper motor 124 resists this bias when the stepper motor 124 is energized. The spring 133 thus applies to the shaft 112 the force, i.e., torque, that is needed to rotate the shaft 112 from the operational position of FIG. 8 to the shutdown position of FIG. 9 when the stepper motor 124 becomes de-energized. The spring 133 thus also serves as a rotation initiator 134 of the rotation management system 132. The rotation apparatus 104 additionally includes an eddy current brake 136 that is cooperable with a flywheel 160 in order to slow the rotational velocity of the shaft 112 when a solid portion 166 of the flywheel 160 is being received between a pair of permanent magnets 154 of the eddy current brake 136, which is when the shaft 112 is beginning to reach the shutdown position. In the depicted exemplary embodiment, the spring 133 is elastically in a free and undeflected state in the shutdown position of FIG. 9. The operation of the eddy current brake 136 on the flywheel 160 reduces the rotational velocity of the shaft 112 as the shaft 112 is beginning to reach the shutdown position so that the shaft 112 settles to the shutdown position wherein the spring 133 is in an elastically undeflected free state. This advantageously avoids the shaft 112 from moving past the shutdown position of FIG. 9 and oscillating back and forth in opposite directions with respect to the shutdown position, which advantageously rapidly places the shaft 112 in the shutdown position and permits a shutdown of a nuclear environment 108 in which the control drum apparatus 106 is situated. It is understood, however, that in alternative embodiments the rotation mechanism 130 or the rotation management system 132 or both can include a radially projected structure situated on the shaft 112 and a fixed stop situated on a support 114, by way of example. With such a geometry, the spring 133 can be configured such that it remains in an elastically deformed position even in the shutdown position of the shaft 112 and thus would bias the radially projecting structure against the fixed stop in order to retain the shaft 112 in the shutdown position of FIG. 9. In this regard, it is understood that the use of such a spring in combination with such a radially projecting structure and a fixed stop potentially could obviate the eddy current brake 136. Such a scenario is completely workable. It is understood, however, that the rotational velocity of the shaft 112 when it reaches the shutdown position may be unknown, and the engagement of the radially projecting structure with the fixed stop might result in a certain level of rotational oscillation of the shaft 112 if the radially projecting structure should rebound from the fixed stop. The eddy current brake 136 thus could still be usefully provided in combination with such a radially projecting structure and a fixed stop. The rotation management system 132 further includes a lock 138 that includes an actuator 172, a bolt 168, and a receptacle 170. More specifically, the actuator is in the form of a linear stepper motor 176 that is situated on a first bracket 172 of the support 114, a rotatable seat 180 that is situated on a second bracket 178 of the support 114, and a threaded shaft 182 that extends between the stepper motor 176 and the rotatable seat 180. The threaded shaft includes a threaded collar 184 that is threadably situated thereon and to which the bolt 168 is affixed. When the stepper motor 176 is electrically energized, it rotates the threaded shaft 182 which causes the threaded collar 184 to non-rotationally translate along the threaded shaft 182 between the first and second brackets 174 and 178 while carrying the bolt 168 therewith. That is, when the threaded shaft 182 rotates, the threaded collar 184 does not rotate therewith and rather the threaded collar 184 non-rotationally translates along the threaded shaft 182. As such, the actuator 172 is electrically operated to move the bolt 168 between a first location, such as is depicted generally in FIG. 11, which is a locked position of the lock 138, and a second location, such as is depicted generally in FIG. 10, in which the lock 138 is in an unlocked position. When the lock 138 is in the locked position, the bolt 168 is received in the receptacle 170, wherein the bolt 168 resists rotation of the shaft 112 away from the shutdown position of FIG. 11. When the lock 138 is in the unlocked position, the bolt 168 is spaced from the receptacle 170, which permits the shaft 112 to be rotated between the shutdown position of FIG. 11 and the operational position of FIG. 10. Since the actuator 172 ceases movement if it is electrically unpowered, the actuator 172 can be unpowered in the locked position of the lock 138, such as during, transport of the nuclear environment 108 in which the control drum 106 is situated, while still retaining the shaft 112 in the shutdown position regardless of the presence or absence of electrical energy to the actuator 172. This advantageously retains the shaft 112 in the shutdown position and thereby avoids an unintended startup of the nuclear environment 108. Furthermore, the rotation mechanism 130 and the rotation management system 132 will rotate the shaft 112 from the operational position to the shutdown position in a very short time in the situation where the stepper motor 124 becomes electrically unpowered. This permits a rapid shutdown of the nuclear environment 108 in which the control drum 160 is situated. It is understood that any of the teachings contained herein with respect to the rotation apparatus 104 can be implemented into the rotation apparatus 4 without departing from the spirit of the instant disclosure. In this regard, any of the teachings may be combined in any fashion to result in advantageous rotation apparatuses that are within the scope of the instant disclosure. Other variations will be apparent. While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular embodiments disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any and all equivalents thereof. |
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description | In the figures, identical elements are identified with the same reference characters. An exemplary embodiment of an x-ray diagnostic device in conformity with the invention is shown in FIGS. 1 and 2. The inventive x-ray diagnostic device has a positioning plate 1 for an examination subject as well as a radiation receiver 2 that are mounted at a base 3. The radiation receiver 2 is a solid state detector and is mounted at a gallows frame 4 so as to be adjustable with respect to the positioning plate 1. The radiation receiver 2 can, as proceeds from FIG. 2, be mounted for this purpose at a first end of a first gallows frame arm 5 oriented substantially horizontally, so as to be adjustable around the orthogonal axes x, y and z. In order to further increase the adjustability of the radiation receiver 2, the first gallows frame arm 5 can be mounted to be adjustable along its longitudinal axis and along a longitudinal axis of a second gallows frame arm 6 oriented substantially vertically to the first arm 5. Via the first gallows frame arm 5, the radiation receiver 2 is thus adjustable in a direction essentially vertical to the longitudinal axis 7 of the positioning plate 2. The distance between the radiation receiver 2 and the positioning plate 1 can be set by adjustment along the second gallows frame arm 6. The magnification scale also can be changed, for example, when a radiation emitter 8 is arranged below the positioning plate 1. It further proceeds from FIGS. 1 and 2 that the positioning plate 1 and/or the radiation receiver 2 are mounted via the gallows frame 4 at a holder 9 at the base 3. Swivelling around a rotational axis 10 can be effected via the holder 9. In addition, it is possible to adjust the holder 9, and thus the positioning plate 1 and the radiation receiver 2 in a vertical direction via a lifting means that is arranged at the base 3 which engages the holder 9. In the scope of the invention, the positioning plate 1 can be seated to be adjustable not only along its longitudinal axis 7, but also along its transverse axis. In FIG. 1 it can be seen that the gallows frame 4 can be adjustably seated at guides along the positioning plate 3 at the holder 9. Figure shows 3 that the radiation receiver 2 can be adjusted in a vertical position by means of swivelling around the x-axis with respect to the surface to the positioning plate 1, so that an examination subject can also be irradiated from the side using a separate radiation emitter for the preparation of an x-ray exposure. FIG. 4 shows how a height adjustment of the positioning plate 1 with respect to the holder 9 allows the radiation receiver 2 to be brought into a position below the positioning plate 1 by rotation around the x-axis and adjustment along the first and second gallows frame arms 5 and 6. An x-ray exposure also can be prepared using a separate radiation emitter, with the separate radiation emitter arranged above the positioning plate 1 and above the examination subject. Such a height adjustment of the positioning plate 1 is, however, only required if not enough room is provided for the radiation receiver 2 below the positioning plate 1. The positioning plate 1 can be brought into a vertical position by means of swivelling and raising the holder 9, wherein so-called wall exposures, i.e. examinations of a standing patient can be performed. Furthermore, it is possible to bring the examination subject into a head exposure position by swivelling in an opposite direction, in order to allow specific x-ray exposures to be prepared. By means of the invention, an x-ray diagnostic device is achieved that allows good accessibility and versatile applicability with a compact structure. Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of their contribution to the art. |
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claims | 1. A system for reduced dose CT scanning of a subject, the system comprising:(a) a pulse generator configured to be coupled to an X-ray source of a CT scanner, the X-ray source being mounted on gantry so as to rotate within a cylindrical enclosure of the CT scanner;(b) said pulse generator configured to periodically switch off emission of X-rays from the X-ray source, using high speed electromagnetic switching on the order of milliseconds, into the cylindrical enclosure; and(c) a processor configured for controlling said pulse generator and receiving an output from said CT scanner;(d) a non-transitory memory storing instructions executable by the processor;(e) wherein said instructions, when executed by the processor, perform steps comprising:(i) controlling timing of the pulse generator so as to intermittently expose a subject to X-rays from the X-ray source at the pre-specified rotation angles of the gantry;(ii) receiving pulsed images from the CT scanner, the pulsed images corresponding to exposures at said pre-specified rotation angles of said X-ray source within the cylindrical enclosure of the CT scanner;(iii) reconstructing each of said exposures to generate a reconstructed image based on using a K-space Weighted Image Contrast (KWIC) through projection view sharing, wherein a central 2D Fourier Transform (2DFT) space, which determines the image contrast, is sampled by projection views of a time frame of interest, and wherein a peripheral 2DFT space is filled by projection views of time frames neighboring a time frame of interest. 2. The system of claim 1:wherein the pulse generator comprises an off-state to restrict X-rays from being emitted from the X-ray pulse generator source and an on-state configured to allow X-rays to be emitted from the X-ray source into the cylindrical enclosure;wherein the pulse generator is coupled to the X-ray source to electromagnetically shield the X-ray source from emitting X-rays in the off-state; andwherein said instructions when executed by the processor further perform steps comprising timing the on-state of the pulse generator and resulting X-ray exposure at said pre-specified rotation angles of the gantry. 3. The system of claim 2:wherein the X-ray source comprises an anode, a cathode and a griddling electrode therebetween; andwherein the pulse generator is configured to modify a negative potential of the griddling electrode to form an electromagnetic field-based shield so as to prevent electron flow from the cathode the anode, thereby stopping emission of X-rays in the off-state. 4. The system of claim 1, wherein said pre-specified rotation angles comprise a sequence of rotation angles selected from the group of rotation angle schemes consisting of: an angle-bisect scheme, a Golden-ratio scheme, and a Tiny Golden-ratio scheme. 5. An apparatus for reducing X-ray dose to a subject in a CT scanner, the CT scanner comprising an X-ray source being mounted on gantry so as to rotate within a cylindrical enclosure of the CT scanner, and a pulse generator coupled to the X-ray source to periodically switch off emission of X-rays from the X-ray source into the cylindrical enclosure, the apparatus comprising:(a) a computer processor coupled to the CT scanner and the pulse generator; and(b) a non-transitory computer-readable memory storing instructions executable by the computer processor;(c) wherein said instructions, when executed by the computer processor, perform steps comprising:(i) controlling timing of the pulse generator so as to intermittently expose a subject to X-rays from the X-ray source at pre-specified rotation angles of the gantry using high speed electromagnetic switching on the order of milliseconds;(ii) receiving pulsed images from the CT scanner, the pulsed images corresponding to exposures at said pre-specified rotation angles; and(iii) reconstructing each of said exposures to generate a reconstructed image based on using a K-space Weighted Image Contrast (KWIC) through projection view sharing, wherein a central 2D Fourier Transform (2DFT) space, which determines the image contrast, is sampled by projection views of a time frame of interest, and wherein a peripheral 2DFT space is filled by projection views of time frames neighboring a time frame of interest. 6. The apparatus of claim 5:wherein the pulse generator comprises an off-state to restrict X-rays from being emitted from the X-ray pulse generator source and an on-state configured to allow X-rays to be emitted from the X-ray source into the cylindrical enclosure;wherein the pulse generator is coupled to the X-ray source to electromagnetically shield the X-ray source from emitting X-rays in the off-state; andwherein said instructions when executed by the processor perform steps comprising timing the on-state of the pulse generator and resulting X-ray exposure at said pre-specified rotation angles of the gantry. 7. The apparatus of claim 6:wherein the X-ray source comprises an anode, a cathode and a griddling electrode there between therebetween; andwherein said instructions when executed by the processor perform steps comprising controlling said X-ray source to modify a negative potential of the griddling electrode to form an electromagnetic field-based shield so as to prevent electron flow from the cathode the anode, thereby stopping emission of X-rays in the off-state. 8. The apparatus of claim 5, wherein said pre-specified angles of rotation comprise a sequence of rotation angles selected from a group of rotation angle schemes consisting of: an angle-bisect scheme, a Golden-ratio scheme, and a Tiny Golden-ratio scheme. 9. A reduced dose CT scanner for generating CT images of a subject, the CT scanner comprising:(a) an X-ray source disposed within a cylindrical enclosure, wherein the cylindrical enclosure comprising a plurality of detectors configured to detect X-rays emitted from the X-ray source, and in which the X-ray source is mounted on a gantry configured to rotate within the cylindrical enclosure of the CT scanner;(b) a pulse generator coupled to the X-ray source, wherein the pulse generator is configured to periodically switch off emission of X-rays from the X-ray source using high speed electromagnetic switching on the order of milliseconds into the cylindrical enclosure; and(c) a computer processor or server coupled to the pulse generator and the plurality of detectors for receiving pulsed images corresponding to exposures at pre-specified rotation angles of the X-ray source within the cylindrical enclosure;(d) a non-transitory memory storing instructions executable by the processor;(e) wherein said instructions, when executed by the computer processor or server, perform steps comprising:(i) timing of the pulse generator which is configured to intermittently expose a subject to X-rays from the X-ray source at pre-specified rotation angles of the gantry;(ii) receiving pulsed images from the CT scanner, the pulsed images corresponding to exposures at said pre-specified rotation angles;(iii) reconstructing each of said exposures to generate a reconstructed image based on using a K-space Weighted Image Contrast (KWIC) through projection view sharing, wherein a central 2D Fourier Transform (2DFT) space, which determines the image contrast, is sampled by projection views of a time frame of interest, and wherein a peripheral 2DFT space is filled by projection views of time frames neighboring a time frame of interest. 10. The CT scanner of claim 9:wherein the pulse generator is configured with an off-state to restrict X-rays from being emitted from the X-ray pulse generator source and an on-state configured to allow X-rays to be emitted from the X-ray source into the cylindrical enclosure;wherein the pulse generator is coupled to the X-ray source to electromagnetically shield the X-ray source from emitting X-rays in the off-state; andwherein said instructions when executed by the computer processor or server perform steps comprising timing the on-state of the pulse generator and resulting X-ray exposure at said pre-specified rotation angles of the gantry. 11. The CT scanner of claim 10:wherein the X-ray source comprises an anode, a cathode and a griddling electrode therebetween; andwherein the pulse generator is configured to modify a negative potential of the griddling electrode to form an electromagnetic field-based shield so as to prevent electron flow from the cathode the anode, thereby stopping emission of X-rays in the off-state. 12. The CT scanner of claim 9, wherein said pre-specified angles of rotation comprise a sequence of rotation angles selected from group of rotation angle schemes consisting of: an angle-bisect scheme, a Golden-ratio scheme, and a Tiny Golden-ratio scheme. 13. A method for reducing X-ray dose upon a subject in a CT scanner, the CT scanner comprising an X-ray source mounted on gantry so as to rotate within a cylindrical enclosure of the CT scanner and emit of X-rays into the cylindrical enclosure, the method comprising:(a) intermittently exposing a subject within the enclosure to X-rays from the X-ray source using high speed electromagnetic switching on the order of milliseconds at pre-specified rotation angles of the gantry;(b) receiving pulsed images from the CT scanner, the pulsed images corresponding to exposures at said pre-specified rotation angles; and(c) reconstructing each of said exposures to generate a reconstructed image based on using a K-space Weighted Image Contrast (KWIC) through projection view sharing, wherein a central 2D Fourier Transform (2DFT) space, which determines the image contrast, is sampled by projection views of a time frame of interest, and wherein a peripheral 2DFT space is filled by projection views of time frames neighboring a time frame of interest. 14. The method of claim 13:wherein the X-ray source comprises focusing an electron beam on an anode from a cathode for generating said X-rays; andwherein intermittently exposing a subject comprises deflecting the electron beam off the anode using a magnetic field, thereby restricting emission of X-rays from the X-ray source into the cylindrical enclosure to control X-ray exposure to the subject only at said pre-specified rotation angles of the gantry. 15. The method of claim 14, further comprising interposing a griddling electrode between the anode and the cathode of the X-ray source fordeflecting the electron beam off the anode in response to generating sufficient negative potential within the griddling electrode to form an electromagnetic field-based shield so as to prevent electron flow from the cathode the anode, thereby stopping emission of X-rays for pre-specified rotation angles. 16. The method of claim 13, further comprising selecting of said pre-specified angles of rotation in response to utilizing a sequence of rotation angles selected from a group of rotation angle schemes consisting of: an angle-bisect scheme, a Golden-ratio scheme, and a Tiny Golden-ratio scheme. |
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042008646 | description | DETAILED DESCRIPTION In FIG. 1, an enclosure of a nuclear power plant encloses three sets of sensor probes R.sub.1 . . . R.sub.n, S.sub.1 . . . S.sub.n, T.sub.1 . . . T.sub.n ; the probes R.sub.1, S.sub.1 and T.sub.1 each measure the same physical characteristics among a number of n physical characteristics. The output signal of each probe R.sub.1 . . . T.sub.n is brought across a conductor to a corresponding comparator circuit R.sub.1 ' . . . T.sub.n '. A second input of each comparator circuit R.sub.1 ' . . . T.sub.n ' is connected to a reference transmitter via a plurality of conductors R.sub.1 " . . . T.sub.n ". The actual circuitry of the comparator circuit R.sub.1 ' . . . T.sub.n ' is well known, as is its function. At the output of each circuit R.sub.1 ' . . . T.sub.n ' appears a signal representing the difference between the value of the references and the value of the output signal of the probe to which it is connected. Circuits for the reproduction of the signals of the same value as the input signal, galvanically separated one with respect to the other and with respect to the input signal, are designated by R.sub.1 .degree. . . . T.sub.n .degree.. Each reproduction circuit R.sub.1 .degree. S.sub.1 .degree. T.sub.1 .degree. is respectively connected to a corresponding probe R.sub.1 S.sub.1 T.sub.1 measuring the physical characteristic "1"through a respective comparator circuit R.sub.1 ' S.sub.1 ' T.sub.1 '. An example of a reproduction circuit which may be used is described in the Belgian patent application No. 1/7598. However, if the value at the input of the reproduction circuit is a binary value, it is possible to choose a simple relay as a reproduction circuit. This further assumes that a relay is considered sufficiently reliable for the physical characteristic under consideration to be transmitted. Each reproduction circuit R.sub.1 .degree. . . . T.sub.1 .degree. comprises six outputs galvanically separated with respect to one another and to the input. A plurality of majority decision circuits V.sub.1 to V.sub.n, each general index k having three inputs and an output, are connected in front of the inputs of six identical logic circuit trains C.sup.1 to C.sup.3 used for intrinsic security. The outputs indexed a, b, c of these circuits are for security, "a" representing, for example, triggering the alarm for the release of the rods; and b and c representing safeguard functions. The majority decision circuits V.sub.1 . . . V.sub.n are each connected to the corresponding reproduction circuits R.sub.1 .degree. . . . R.sub.n .degree., S.sub.1 .degree. . . . S.sub.n .degree., T.sub.1 .degree. . . . T.sub.n .degree. which in turn are connected to comparator circuit R.sub.1 ' . . . R.sub.n ', S.sub.1 ' . . . S.sub.n ', T.sub.1 ' . . . T.sub.n ' and to the probes R.sub.1 . . . R.sub.n, S.sub.1 . . . S.sub.n, T.sub.1 . . . T.sub.n, each probe of same index 1 . . . n measuring the same physical characteristic "k" taken from 1 . . . n. These are the majority decision circuits which are "two of three" and which are well known in the regulation and automation art. They produce therefore an output signal corresponding to two identical input signals, one of the input signals capable of being different from the other two. As a result, the breakdown of one of the probes R.sub.1 . . . R.sub.n, S.sub.1 . . . S.sub.n, T.sub.1 . . . T.sub.n or of its associated comparator circuit R.sub.1 ' . . . R.sub.n ', S.sub.1 ' . . . S.sub.n ', T.sub.1 ' . . . T.sub.n ' or of the associated reproduction circuit R.sub.1 .degree. . . . R.sub.n .degree., S.sub.1 .degree. . . . S.sub.n .degree., T.sub.1 .degree. . . . T.sub.n .degree. does not modify the input signal to the logic circuit trains C. The six trains C.sup.1, C.sub.1, C.sup.2, C.sub.2, C.sup.3, C.sub.3 are assembled in three pairs by means of nine AND functional logic circuits. Each pair C.sup.1, C.sub.1 ; C.sup.2, C.sub.2 ; C.sup.3, C.sub.3 is associated with three AND functional logic circuits E.sub.1.sup.a, E.sub. 1.sup.b, E.sub.1.sup.c ; E.sub.2.sup.a, E.sub.2.sup.b, E.sub.2.sup.c ; E.sub.3.sup.a, E.sub.3.sup.b, E.sub.3.sup.c by means of three different outputs. In their turn, the outputs of the groups E.sub.1.sup.a, E.sub.2.sup.a, E.sub.3.sup.a ; E.sub.1.sup.b, E.sub.2.sup.b, E.sub.3.sup.b ; E.sub.1.sup.c, E.sub.2.sup.c, E.sub.3.sup.c are connected to the inputs of the functional OR logic circuits or "two of three" majority decision circuits respectively U.sup.a, U.sup.b, U.sup.c. The U.sup.a group can, for example, control a retention system for control rods, permitting, upon receipt of an emergency signal, release of the control rods such that they fall freely into the reactor acting as stop rods. In this case, the output signals of the groups E.sup.a, or E.sub.1.sup.a, E.sub.2.sup.a, E.sub.3.sup.a (FIG. 2) represent the state of the emergency alert signals. To prevent that a fault in one of the circuits E.sub.1.sup.a, E.sub.2.sup.a, E.sub.3.sup.a sets off the emergency signal, U.sup.a can be a "two of three" majority decision circuit, in this situation by means of three pairs of circuit breakers in parallel. Placed in series with the windings D.sub.1.sup.1, D.sub.1.sup.2, D.sub.2.sup.1, D.sub.2.sup.2, D.sub.3.sup.1, D.sub.3.sup.2 which have a minimum voltage are output signals of the circuits E.sub.1.sup.a, E.sub.2.sup.a, E.sub.3.sup.a. Each circuit breaker of one pair in parallel comprises a winding fed by a different signal than that feeding the winding of the other circuit breakers of the pair in parallel. For example: D.sub.1.sup.1, D.sub.3.sup.2 ; D.sub.2.sup.1, D.sub.1.sup.2 ; D.sub.3.sup.1, D.sub.2.sup.2. In this way, an interruption of the current in a conductor A in circuit with the three pairs of circuit breakers cannot take place in the case where at least two of the three signals E.sub. 1.sup.a, E.sub.2.sup.a, E.sub.3.sup.a transmit the emergency signal. In effect, if only E.sub.1.sup.a transmits the emergency signal, the maintenance current in the conductor A circulates via D.sub.3.sup.2 D.sub.2.sup.1 D.sub.3.sup.1. If E.sub.2.sup.a transmits the emergency signal, the current circulates via D.sub.3.sup.2 D.sub.1.sup.2 D.sub.3.sup.1. If E.sub.3.sup.a transmits the emergency signal, the current circulates via D.sub.1.sup.1 D.sub.2.sup.1 D.sub.2.sup.2. For the current to be cut, it is necessary that two of the groups E.sub.1.sup.a, E.sub.2.sup.a, E.sub.3.sup.a transmit the emergency signal. U.sup.a is thus "two of three" functional majority decision circuit. The circuit U.sup.b can, for example, control the introduction of emergency feed water into a stream generator in case of a loss of normal feed water. This feed water removes the thermal power produced in the reactor. In case of emergency, the signals of the output of the devices E.sub.1.sup.b, E.sub.2.sup.b, E.sub.3.sup.b activate, on the one hand, (FIG. 3) an emergency pumps P.sub.1, P.sub.2, P.sub.3 disposed in parallel pipes in series with check valves Z, feeding a common conduit C.sub.P from a recovery water circuit H to the condenser. From this Conduit C.sub.P pipes emanate to manually remote-controlled valves V.sub.P.sup.1, V.sub.P.sup.2, V.sub.P.sup.3. These valves are connected to check valves Z of the type which can be maintained open. The output signals of the devices E.sub.1.sup.b, E.sub.2.sup.b, E.sub.3.sup.b are applied on the other hand to a functional OR sub-circuit U.sub.Q.sup.b activating a turbo-pump Q when any one of the devices E.sub.1.sup.b, E.sub.2.sup.b, E.sub.3.sup.b transmits an alarm. The turbo-pump Q feeds water from the recovery circuit H to the condenser via a common conduit C.sub.Q which connects pipes through the manually remote-controlled valves V.sub.Q.sup.1, V.sub.Q.sup. 2, V.sub.Q.sup.3 followed equally by check valves Z. The valves V.sub.Q.sup.1, V.sub.Q.sup.2, V.sub.Q.sup.3 can thus equally remain normally open. The valves V.sub.P.sup.1, V.sub.Q.sup.1 ; V.sub.P.sup.2, V.sub.Q.sup.2 ; V.sub.P.sup.3, V.sub.Q.sup.3 feed in parallel, respectively, three steam generators G.sup.1, G.sup.2, G.sup.3. The circuit U.sup.b is thus in fact a functional OR hydraulic circuit for the emergency feeding of feed water of each generator G.sup.1, G.sup.2, G.sup.3. The circuit U.sub.c can, for example, control a system of boric acid release in the reactor in the event of an uncontrollable accident in releasing the control bars. One such system (FIG. 4) comprises a high pressure circuit having an injection reservoir I and a group of injection pumps F.sub.1, F.sub.2, F.sub.3, as well as a low pressure circuit comprising an expansion reservoir J and circulation pumps K.sub.1, K.sub.2, K.sub.3. Pneumatic valves W.sub.1, W.sub.2, W.sub.3 make it possible to cut communication between the high pressure circuit and the low pressure circuit. Motor-operated, remote-controlled valves X.sub.1, X.sub.2, X.sub.3 make it possible to establish communication between the reactor and the high pressure circuit. In normal operation, the injection pumps F.sub.1, F.sub.2, F.sub.3 are stopped and the motor-operated valves X.sub.1, X.sub.2, X.sub.3 are closed and isolate the high pressure circuit with respect to the reactor. The pneumatic valves W.sub.1, W.sub.2, W.sub.3 are open. One of the circulation pumps K.sub.1 operates and maintains the boric acid in movement through the low and high pressure circuits forcing it to pass through a heating apparatus M to avoid the local crystal precipitation of boric acid at cooler locations. The functional logics E.sub.1.sup.c, E.sub.2.sup.c, E.sub.3.sup.c circuits transmit alarm signals of "borification" which result in: the closing of the corresponding pneumatic valves W.sub.1, W.sub.2, W.sub.3 ; the stopping of the circulation pumps K.sub.1, K.sub.2, K.sub.3, isolating the low pressure circuit from the high pressure circuit. Simultaneously, the output signals of the circuits E.sub.1.sup.c, E.sub.2.sup.c, E.sub.3.sup.c start the injection pumps F.sub.1, F.sub.2, F.sub.3 and open the motorized valves X.sub.1, X.sub.2, X.sub.3. At this moment, 12% boric acid is injected into the reactor which suppresses the neutron flux. The group U.sup.c shown in FIG. 4 is in fact an OR functional circuit. It is obviously possible to conceive of other variations of this U.sup.c group, for example, to use only two outputs (for example, the circuits E.sub.1.sup.c and E.sub.2.sup.c) keeping in reserve the third (E.sub.3.sup.c) for substituting it for one or other of E.sub.1.sup.c or E.sub.2.sup.c during the tests. In this latter case, triple redundancy is reduced to double redundancy. The installation according to the invention has a very high security due to the fact that each control is at least duplicated. It has the advantage of avoiding the untimely emergency stops due to a defect in the logic circuit train because these trains are duplicated for each command chain and connected by functional AND logic circuits. As these logic circuit trains can be very complex, conformity surveillance circuits Y can be provided between corresponding points of the two trains connected by an AND circuit. The Y circuits can activate for example, indicators on a surveillance board. In FIG. 1, a conformity surveillance circuit Y is represented which compares the outputs of the selector circuits V.sub.1 associated with the logic circuit trains C.sup.2 and C.sub.2. Other Y circuits can be associated with other characteristic points corresponding to the circuits C.sup.2 and C.sub.2 as symbolically shown by the oblique lines. In reality, such Y circuits are associated to each pair of logic circuit trains C.sup.1, C.sub.1 ; C.sup.2, C.sub.2, C.sup.3, C.sub.3. All of the Y circuits associated with a pair of logic circuit trains can additionally be connected between themselves in a manner known in and of itself by a general security control device signalling the absence of conformity in any one of the Y circuits associated with the pair of logic circuit trains in question. The general control device can, for example, constitute a circuit according to French Pat. No. 1,466,050 to the inputs of which are connected the outputs of all of the Y circuits associated with the same pair of logic circuit trains. It is possible to test the installation without endangering either normal operation, or its security nor even its availability in case of simple failure. In effect, as each physical characteristic is measured by three different sensors, a defect in one sensor or one of the elements R.sub.1 ' . . . R.sub.n ', S.sub.1 ' . . . S.sub.n ', T.sub.1 ' . . . T.sub.n ' or R.sub.1 .degree. . . . R.sub.n .degree., S.sub.1 .degree. . . . S.sub.n .degree., T.sub.1 .degree. . . . T.sub.n .degree. can be detected by the comparison of the corresponding inputs R.sub.1 .degree. . . . R.sub.n .degree., S.sub.1 .degree. . . . S.sub.n .degree., T.sub.1 .degree. . . . T.sub.n .degree. of any one of the six logic circuit trains C.sup.1 to C.sub.3. Further, each of the six logic circuit trains C.sup.1 to C.sub.3 can be individually tested while at the same time permitting the normal operation of the five remaining circuits. As the test of a single logic circuit train C.sup.1 to C.sub.3 necessitates several hours, this safeguard requirement of the security and of the availability of the installation is hardly superfluous. In order to take into account also defects in one or the other electric feed systems the logic circuit trains of the same pair can be attached to different feeds. In this case, the AND logic functional circuit terminals of this pair can transmit the alarm by the absence of electric signal, that is to say when the two feeds break down. On the contrary, if the identical circuit logic trains of the same pair are fed by the same source of electric current, the alarm is transmitted only by the presence of an electric signal. In a general manner, as the control installation of a nuclear power plant comprises normally four feed systems, one can provide either on the one hand pairs of logic circuit trains in which the two trains are fed by the same source of current but a feed by sources of different currents for the pairs of the different logic circuit trains, or by pairs of logic circuit trains in which each train is fed by a source of different current. Under the conditions described hereinabove, and if the OR functional circuits are "two of three" majority decision circuits, the process control installation activates an emergency control only if simultaneously two of three feed systems used break down. It is apparent that in each case one uses, among the electric feed systems available, the three most reliable. While the invention has been described, it will be understood that it is capable of further modifications and this application is intended to cover any modifications, uses or adaptations of the invention following in general the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains, and as may be applied to the essential features hereinbefore set forth and as fall within the scope of the invention or limits of the appended claims. |
055132316 | abstract | A skid for transporting a nuclear fuel transportation cask. The skid comprises a supporting member having parallel spaced-apart plates. The plates are aligned perpendicular to a longitudinal axis of the cask, include a semi-circular trough for mating with the cask, and are connected by longitudinal fins parallel to the longitudinal axis of the cask. The skid also comprises a retaining member including parallel spaced-apart plates. The plates of the retaining member are aligned perpendicular to a longitudinal axis of the cask, include a trough for mating with the cask, and are connected by longitudinal fins parallel to the longitudinal axis of the cask. The fins of the supporting member are spaced apart such that when the cask rests in the trough of the supporting member, the fins of the supporting member are aligned with elongate members of the cask neutron radiation shielding material to transfer the load between the cask and the skid. |
summary | ||
description | This disclosure generally relates to radiographic imaging systems and methods, and more particularly to bases for holding image receptors used in radiographic imaging systems and methods. Various types of radiographic devices are generally known in the art. A known x-ray unit for podiatry is disclosed in U.S. Pat. No. 4,587,668, which is assigned to the same assignee as the present disclosure. Generally, such x-ray units include a platform upon which are placed the feet of a patient to be x-rayed. The platform is elevated above floor level to allow film cassettes to be positioned in a film well located below the platform. The platform may further include a slot for receiving a vertically oriented film cassette. A radiographic head is mounted on vertical mounting members, which serve to space the radiographic head a desired distance above the foot platform. The vertical mounting members are moveable in both the lateral and longitudinal directions so that x-rays of a patient's feet can be taken from many angles while easily maintaining the same source to image distance (SID). Some radiographic techniques require the patient to place weight on the subject area as the image is captured. A podiatrist, for example, may require certain foot x-rays to be taken where the patient must stand on top of the image receptor during image capture. In some scenarios, a podiatrist may need multiple different images, such as lateral, medial oblique, and anteroposterior (AP) projections, that may require the patient to be repositioned for each image. Repositioning of feet for different views is often difficult or dangerous for elderly patients or individuals whose balance or ability to move on the platform is impaired due to disease or other conditions, such as arthritis. More recently, electronic methods (such as direct radiography (DR) and computed radiography (CR)) have been developed to obtain and display radiographic images without the use of film. In DR and CR, a reusable image receptor is used to map radiation levels during a radiographic procedure and store the data electronically. This data can then be used to display a radiographic image. While the image receptors used in DR and CR processes may be convenient and less expensive to use than film, the digital conversion process used to obtain and generate images is more sensitive to inaccuracies in measured radiation levels. Consequently, it is important to properly position the patient relative to the image receptor in order to capture the desired type of radiographic image. Additionally, to obtain weight-bearing images, the patient typically stands directly on the image receptor, making proper positioning of the patient more difficult. Still further, while the use of digital image receptors provides an opportunity to capture multiple images on a single receptor, the patient must be precisely aligned with the desired portion of the image receptor and therefore further repositioning of the patient is needed. In accordance with one aspect of the present disclosure, a radiographic device for use with an image receptor may include a base assembly having a frame defining a frame top opening and a platform supported by the frame and extending over the frame top opening, the platform defining a lateral direction and a longitudinal direction substantially perpendicular to the lateral direction, the platform and frame defining a base receptacle disposed below the platform. An arm assembly may have a first end pivotably coupled to the base assembly and a second end, and a radiographic head may be coupled to the arm assembly second end. A carriage assembly may be disposed in the base receptacle and include a tray sized to receive the image receptor, the tray being supported for movement in both the lateral and longitudinal directions. In accordance with another aspect of the present disclosure, a radiographic device for use with an image receptor may include a base assembly having a frame defining a frame top opening and a platform supported by the frame and extending over the frame top opening, the platform and frame defining a base receptacle disposed below the platform. An arm assembly may have a first end pivotably coupled to the base assembly and a second end, and a radiographic head may be coupled to the arm assembly second end. A tray may be disposed in the base receptacle and sized to receive the image receptor. The device may further include a base collimator assembly having a collimator plate positioned between the platform and the tray and defining a collimator aperture through which radiographic energy is admitted into the base receptacle, a first collimator blade slidable relative to the collimator plate and movable to an extended position in which at least a portion of the first collimator blade is aligned with a first portion of the aperture, and a second collimator blade slidable relative to the collimator plate and movable to an extended position in which at least a portion of the second collimator blade is aligned with a second portion of the aperture. In accordance with another aspect of the present disclosure, a radiographic device for use with an image receptor may include a base assembly having a frame defining a frame top opening and a platform supported by the frame and extending over the frame top opening, the platform defining a lateral direction and a longitudinal direction substantially perpendicular to the lateral direction, the platform and frame defining a base receptacle disposed below the platform. An arm assembly may have a first end pivotably coupled to the base assembly and a second end, and a radiographic head may be coupled to the arm assembly second end. A carriage assembly may be disposed in the base receptacle and include a tray sized to receive the image receptor, the tray being supported for movement in both the lateral and longitudinal directions. The device may further include a base collimator assembly having a collimator plate positioned between the platform and the tray, the collimator plate defining a collimator aperture through which radiographic energy is admitted into the base receptacle, a first collimator blade slidable relative to the collimator plate and movable to an extended position in which at least a portion of the first collimator blade is aligned with a first portion of the aperture, and a second collimator blade slidable relative to the collimator plate and movable to an extended position in which at least a portion of the second collimator blade is aligned with a second portion of the aperture. It should be understood that the drawings are not necessarily to scale and that the disclosed embodiments are sometimes illustrated diagrammatically and in partial views. In certain instances, details which are not necessary for an understanding of the disclosed methods and apparatuses or which render other details difficult to perceive may have been omitted. It should be understood, of course, that this disclosure is not limited to the particular embodiments illustrated herein. This disclosure relates to apparatus and methods of positioning a patient relative to an image receptor during radiographic procedures. Radiographic devices may include a base upon which the patient may stand. The base may include a support for bearing the weight of the patient above the receptor. A carriage assembly capable of longitudinal and lateral translation may hold the image receptor. Translation of the carriage assembly permits the image receptor to move into alignment with a target area of the patient while the patient's feet remain stationary, thereby minimizing patient movement. Additionally, a base collimator may be provided to limit the area of the image receptor that is used during image capture which, in combination with the carriage assembly, allows different portions of the same image receptor to capture different images with minimal patient repositioning. The radiographic device of the present disclosure is similar to those disclosed in U.S. Pat. Nos. 4,587,668 and 6,863,439, which have the same assignee as the present disclosure and are incorporated herein by reference. The primary differences between the present device and those of the '668 and '439 patents lie in a base assembly on which the patient may stand during capture of radiographic images, described in greater detail below with reference to FIGS. 5-9. Referring now to the drawings, and with specific reference to FIG. 1, a radiographic device 20 is described and illustrated herein for use in podiatry treatment, but the teachings provided herein may be applied to radiographic devices used in other fields. The radiographic device 20 includes a base assembly 22 on which a patient may be positioned during image capture. Hand rail legs 26 are mounted to the base assembly 22 and provide a patient support hand rail. As shown in FIG. 1, a head mounting assembly 28 has a first end 30 pivotably coupled to the base assembly 22 and a second end 32 connected to the radiographic head 34. As used herein, the radiographic head is meant to include a power source and an associated collimator which is attached to and depends from the power source. The power source is capable of emitting electromagnetic radiation sufficient to generate x-ray images. The mounting assembly 28 includes a pair of vertical mounting members 36 having lower ends disposed in a mounting apparatus 38. The mounting apparatus 38 may include spring loaded mounting means for holding the vertical mounting members 36 in a desired position, such as the mounting means disclosed in U.S. Pat. No. 4,587,668 assigned to the current assignee and incorporated herein by reference. Alternatively, other means for holding the vertical mounting members 36 in place may also be used. The upper ends of the vertical mounting members 36 are coupled to a U-shaped mounting plate 40 using bolts 42. A horizontal mounting member 44 has a first end attached to the U-shaped mounting plate 40 and a free second end carrying a collar 46. The horizontal mounting member 44 is hollow to define an internal socket 48. A yoke 50 is provided for coupling the radiographic head 34 to the mounting assembly 28 and allowing angular adjustment not only about the Y axis, but also about an axis that is parallel to the lateral direction, referred to herein as the X axis (FIG. 2). In the illustrated embodiment, the yoke 50 includes an outer bracket 52 having a stub shaft sized for insertion into the socket 48 of the horizontal member 44. The outer bracket 52 includes a cross support 56 attached to the stub shaft and spaced, generally parallel outer arms 58 attached to opposite ends of the cross support 56. In the illustrated embodiment, the yoke 50 further includes an inner bracket 60 attached to a back plate 62 of the radiographic head 34. The inner bracket 60 includes a cross member 64 spanning a width of the radiographic head and two inner arms 66 attached to opposite ends of the cross member 64. The inner bracket 60 is sized to closely fit inside the outer bracket 52 so that, when the radiographic head 34 is oriented in the position shown in FIG. 3, the outer arms 58 overlie the inner arms 66. The back plate 62 includes a threaded aperture 63 for receiving a fastener 65. The fastener 65 passes through a hole in the cross member 64 thereby to secure the inner bracket 60 to the radiographic head back plate 62. Pins 68 are attached to the inner arms 66 and pass through holes formed in the outer arms 58 to pivotably couple the inner bracket 60 to the outer bracket 52. Free ends of the pins 68 are threaded to receive knobs 70 which may be rotated to secure the inner bracket 60 and radiographic head 34 at a desired angle with respect to the outer bracket 52. The outer bracket 52 further includes a set screw assembly having a bracket 72 attached to the cross support 56. A threaded aperture 74 is formed in the bracket 72 and is sized to receive a set screw 76. The set screw 76 has a length sufficient so that an end of the set screw is engageable with the collar 46. As a result, the set screw 76 may be loosened to allow the stub shaft 54 of the yoke 50 to rotate within the socket 48, thereby adjusting the angle of the radiographic head 34 about the X axis. The set screw 76 may then be tightened to engage the collar 46 thereby locking the yoke 50 and attached radiographic head 34 in the desired position. The radiographic head 34 described herein permits adjustment of the head for multiple projections. For example, the vertical mounting members 36 may be rotated laterally in directions S or T as shown in FIG. 1 and the radiographic head 34 may be rotated about the Y axis defined by the horizontal mounting member 44 and stub shaft 54 to obtain lateral or medial oblique projections. For these projections, the vertical mounting members 36 form substantially a right angle to the longitudinal direction, as illustrated at FIG. 3. In addition, the vertical mounting members 36 may be rotated longitudinally in directions Q and R and the outer bracket 52 of the yoke 50 may be adjusted to an appropriate angle about the X axis defined by the pins 68 to obtain additional projections such as the AP projection, as illustrated at FIG. 4. The yoke 50 allows the radiographic head 34 to be tilted about the X axis so that the radiographic head 34 is directed to substantially the same target area. While a particular type of adjustable radiographic head 34 is described herein, it will be appreciated that other types of radiographic heads and supports therefor may be used without departing from the scope of the claims. The base assembly 22 may support any load applied thereto independently of an image receptor 80. The image receptor 80 may be may be any type of receptor, such as a cassette, panel, or film, used to capture images from CR, DR, or other types of radiographic procedures. In the embodiment illustrated in FIGS. 5-9, the base assembly 22 includes a frame 82 which may be formed out of structural components such as steel rectangular tube. The frame 82 may define a frame top opening 84 and a frame side opening 86. The base assembly 22 may also include a platform 88 (FIG. 1) supported by the frame 82 that extends over the frame top opening 84. As understood more fully below, the platform 88 may be formed of a material that is sufficiently strong to withstand the weight of a patient that is also radiolucent (i.e., partly or wholly permeable to radiation and especially X rays). In some embodiments, for example, the platform 88 may be formed of a thermoplastic polycarbonate having a thickness of approximately ½ inch. The platform 88 may be configured to define a lateral direction 90 and a longitudinal direction 92 that are consistent with the lateral directions S, T and longitudinal directions Q, R of the vertical mounting members 36. When assembled, the frame 82 and platform 88 define a base receptacle 94 disposed below the platform 88. The base assembly 22 may further include a pedestal 96 coupled to the frame 82 and defining a top wall 98. As best shown in FIG. 5, the pedestal 96 may include pedestal side walls 100, 102 extending downwardly from the top wall 98. A pin 104 may project upwardly from the top wall 98. A carriage assembly 110 may be disposed in the base receptacle 94 and may include a tray 112 sized to receive the image receptor 80, as best shown in FIG. 6. The carriage assembly 110 may be supported in a non-weight bearing relationship relative to the patient platform 88. In the illustrated embodiment, the carriage assembly 110 is supported by the frame 82 independently of the platform 88, so that loads applied to the platform 88 are not transferred to the carriage assembly 110. Specifically, the carriage assembly 110 is supported by the platform 98 that is attached to a bottom of the frame 82, while the platform 88 lies over and is supported by a top of the frame 82. The tray 112 may be supported for movement in multiple directions, such as in both the lateral and longitudinal directions. In the embodiment illustrated in FIGS. 6 and 7, the carriage assembly 110 includes a carrier 114 adapted to slide along the pedestal 96. More specifically, the carrier 114 includes a carrier top plate 116 and carrier side walls 118, 120. The carrier side walls 118, 120 are spaced by a distance to closely fit over the pedestal side walls 100, 102. Accordingly, when the carrier 114 is positioned above the pedestal 96, the close fit of the carrier side walls 118, 120 over the pedestal side walls 100, 102 guide the sliding movement of the carrier 114 (and tray 112 coupled thereto) along the pedestal 96. In the illustrated embodiment, movement of the carrier 114 along the pedestal 96 is in the lateral direction. The carrier 114 may further include a lever 122 to allow an operator to manually slide the carrier 114 laterally along the pedestal 96. As best shown in FIG. 7, the lever 122 is pivotably mounted to the carrier 114 and includes a handle end 124 and a connection end 126. The connection end 126 is disposed below the carrier 114 and includes an aperture 128 sized to fit over the pin 104 on the pedestal 96. The handle end 124 extends longitudinally through the frame side opening 86 to permit an operator to grasp and manipulate the lever 122. In operation, when the aperture 128 is fitted over the pin 104, the pin 104 is held in a fixed position by the pedestal 96 so that a lateral force applied to the handle end 124 of the lever 122 will slide the carrier 114 along the pedestal 96. The carriage assembly 110 may further include one or more slide assemblies 130 to permit movement of the tray 112 in the longitudinal direction. As best shown in FIGS. 6 and 7, the carriage assembly 110 may include two slide assemblies 130, each slide assembly 130 being disposed between the carrier 114 and the tray 112. In the illustrated embodiment, the slide assemblies 130 are provided as roller drawer sliders, however any device that permits translation of the tray 112 relative to the carrier 114 may be used. The slide assemblies 130 may be oriented to permit movement of the tray 112 in the longitudinal direction. In operation, the user may simply grasp the tray 112 and apply a longitudinal force to slide the tray 112 in the longitudinal direction. The slide assemblies 130 may be configured to permit the tray 112 to travel in the longitudinal direction between an image capture position, in which the tray 112 is disposed within the base receptacle 94, and a receptor loading position, in which the tray 112 is positioned at least partially outside of the base receptacle 94. In the illustrated embodiment, the tray 112 passes at least partially through the frame side opening 86 as it moves between the image capture and tray loading positions. A base collimator assembly 140 may be provided to limit the area of the image receptor 80 that is exposed to radiographic energy during a radiographic procedure, thereby to facilitate the capture of multiple images on a single image receptor 80, as best shown in FIGS. 8 and 9. The base collimator assembly 140 may include a collimator plate 142 positioned between the platform 88 and the tray 112. The collimator plate 142 may define a collimator aperture 144 through which radiographic energy is admitted into the base receptacle 94. In the illustrated embodiment, the collimator aperture 144 has a rectangular shape that includes opposed lateral edges 146, 148 and opposed longitudinal edges 150, 152, however other aperture shapes may be used. Referring to FIG. 8, the base collimator assembly 140 may further include first and second collimator blades 154, 156 for adjusting the effective size of the collimator aperture 144. The first collimator blade 154 is supported for slidable movement relative to the collimator plate 142 between a retracted position, in which the first collimator blade 154 is positioned outside of the collimator aperture 144, and an extended position, in which at least a portion of the first collimator blade 154 is aligned with a first portion 158 of the aperture located adjacent lateral edge 146. Similarly, the second collimator blade 156 is supported for slidable movement relative to the collimator plate 142 between a retracted position, in which the second collimator blade 156 is positioned outside of the collimator aperture 144, and an extended position, in which at least a portion of the second collimator blade 156 is aligned with a second portion 160 of the aperture located adjacent lateral edge 148. The collimator plate 142 and first and second collimator blades 154, 156 may be formed of a material that is radio-opaque (i.e., not transparent to X-rays or other forms of radiation) to block the passage of radiographic energy and prevent associated portions of the image receptor 80 from being used. In the illustrated embodiment, the first and second collimator blades 154, 156 are adjustable between the retracted and extended positions independently of each other. As best shown in FIG. 9, a first blade lever 162 is pivotably coupled to the collimator plate 142 and includes a handle end 164 and a connection end 166. The connection end 166 is pivotably coupled to the first collimator blade 154 so that a lateral force applied to the handle end 164 will pivot the first blade lever 162 and move the first collimator blade 154. Similarly, a second blade lever 168 is pivotably coupled to the collimator plate 142 and includes a handle end 170 and a connection end 172. The connection end 172 is pivotably coupled to the second collimator blade 156 so that a lateral force applied to the handle end 170 will pivot the second blade lever 168 and move the second collimator blade 156. In operation, the carriage assembly 110 may reduce the amount of patient positioning and repositioning needed during radiographic procedures. By providing a separate platform 88 for supporting the weight of the patient and providing the movable carriage assembly 110 to hold the image receptor 80, the position of the image receptor 80 may be adjusted to obtain the desired projection. Minimal movement of the patient, such as side stepping small distances, may be needed to align the foot of interest with the center line of the X-ray source, thereby eliminating the need for the patient to rotate to acquire the same view. Furthermore, multiple different projections may be obtained while the patient remains stationary on the platform 88, thereby further reducing the amount of patient repositioning. In addition, the base collimator assembly 140 permits multiple different images to be captured on different portions of the same image receptor 80. For example, one or both of the collimator blades 154, 156 may be moved to the extended position to block one or more portions of the collimator aperture 144, thereby reducing the effective area of the collimator aperture 144. The carriage assembly permits the image receptor 80 to be moved so that a first desired portion of the image receptor 80 is aligned with the effective area of the collimator aperture 144. After a first image is captured in the first desired portion of the image receptor, the collimator blades 154, 156 and/or the carriage assembly 110 may be adjusted so that an effective area of the collimator aperture 144 is aligned with a second desired portion of the image receptor that is different than the first desired portion. A second image may then be captured in the second desired portion. While only certain embodiments have been set forth, alternatives and modifications will be apparent from the above description to those skilled in the art. These and other alternatives are considered equivalents and within the spirit and scope of this disclosure and the appended claims. |
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claims | 1. A nuclear power plant comprising:a first reactor containment vessel internally having a dry well and a pressure suppression chamber mutually isolated, said pressure suppression chamber forming a suppression pool being filled with cooling water;a reactor pressure vessel disposed in said dry well in said first reactor containment vessel;a second reactor containment vessel surrounding said first reactor containment vessel and forming a cooling water pool being filled with cooling water at a bottom, said cooling water pool in said second reactor containment vessel adjoining said suppression pool with said first reactor containment vessel intervening between these pools;a steam discharge apparatus; anda reactor cooling apparatus,wherein said steam discharge apparatus has a steam discharge pipe connected to said reactor pressure vessel and immersed in said cooling water in said suppression pool, and a first open/close valve installed in said steam discharge pipe;wherein the reactor cooling apparatus has an evaporator installed in said reactor pressure vessel for evaporating a cooling medium, a condenser disposed in an inner space delimited by said first reactor containment vessel and said second reactor containment vessel above said cooling water pool for condensing steam of said cooling medium generated in said evaporator, a first pipe path connected to said evaporator and said condenser by passing through a side wall of said reactor pressure vessel and a side wall of said first reactor containment vessel, said first pipe path introducing said steam of said cooling medium generated in said evaporator, a second pipe path connected to said condenser and said evaporator by passing through said side wall of said reactor pressure vessel and said side wall of said first reactor containment vessel, said second pipe path introducing a liquid of said cooling medium generated in said condenser to said evaporator, and a second open/close valve installed in either said first pipe path or said second pipe path;wherein said evaporator is disposed above a regular water level in said reactor pressure vessel;wherein said inner space in which said condenser is disposed is communicated with an air discharge portion attached to a ceiling of said second reactor containment vessel, said air discharge portion being disposed above said evaporator, and said inner space is communicated with an air supply portion attached to a side wall of said second reactor containment vessel above a liquid surface of said cooling water pool and below said condenser, said inner space introducing air for removing decay heat generated in fuel assemblies in a core disposed in said reactor pressure vessel,wherein said condenser is a condenser condensing said steam of said cooling medium by said air ascending in said inner space from said air supply portion toward said air discharge portion; andwherein said inner space is configured to provide continuous air flow between the cooling water pool and the air discharge portion. 2. The nuclear power plant according to claim 1, wherein said second pipe path is disposed in said cooling water pool and said suppression pool. 3. The nuclear power plant according to claim 2, wherein a compressor is installed in said first pipe path, and a turbo-motor rotating with steam in said reactor pressure vessel being supplied is connected to said compressor, and said second open/close valve installed in said second pipe path is an expansion valve. 4. The nuclear power plant according to claim 3, wherein a third open/close valve is installed on a steam pipe connected to said reactor pressure vessel and said turbo-motor; and a battery is connected to said third open/close valve. 5. The nuclear power plant according to claim 1, wherein a compressor is installed in said first pipe path, and a turbo-motor rotating with steam in said reactor pressure vessel being supplied is connected to said compressor, and said second open/close valve installed in said second pipe path is an expansion valve. 6. The nuclear power plant according to claim 5, wherein a third open/close valve is installed on a steam pipe connected to said reactor pressure vessel and said turbo-motor; and a battery is connected to said third open/close valve. 7. The nuclear power plant according to claim 1,wherein said air discharge portion includes an air discharge pipe provided with a third open/close valve, and said air supply portion includes an air supply pipe provided with a fourth open/close valve, andwherein a first battery is connected to said third open/close valve and a second battery is connected to said fourth open/close valve. |
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description | An electron beam exposure apparatus according to a preferred embodiment of the present invention will be described below with reference to the accompanying drawings. The electron beam exposure apparatus is merely an application of the present invention, and the present invention can be applied to an exposure apparatus using a charged-particle beam such as an ion beam other than an electron beam. (Description of Building Component of Electron Beam Exposure Apparatus) FIG. 1A is a sectional view schematically showing the main part of the electron beam exposure apparatus according to the preferred embodiment of the present invention. FIG. 1B is a plan view showing the electron beam exposure apparatus in FIG. 1A when viewed from above. FIG. 1A illustrates the sections of magnetic lens arrays 21, 22, 23, and 24. The exposure apparatus comprises a plurality of multi-source modules 1 serving as an electron beam source which emits an electron beam. Each multi-source module 1 forms a plurality of electron source images, and emits a plurality of electron beams corresponding to the respective electron source images. The multi-source modules 1 are arrayed in a 3xc3x973 matrix in this embodiment. The multi-source modules 1 will be described in detail below. The magnetic lens arrays 21, 22, 23, and 24 are interposed between the plurality of multi-source modules 1 and a stage 5. Each magnetic lens array is constituted by vertically arranging, at an interval, two magnetic disks MD having openings of the same shape which are arrayed in a 3xc3x973 matrix in correspondence with the array of the multi-source modules 1. The magnetic disks MD of the magnetic lens arrays 21, 22, 23, and 24 are excited by common coils CC1, CC2, CC3, and CC4. Each opening functions as the magnetic pole of each magnetic lens ML, and generates the same lens magnetic field in design. A plurality of electron source images formed by each multi-source module 1 are projected on a wafer 4 held on the stage 5 via corresponding four magnetic lenses (ML1, ML2, ML3, and ML4) of the magnetic lens arrays 21, 22, 23, and 24. An electron-optic system which causes a field such as a magnetic field to act on an electron beam until the electron beam emitted by one multi-source module 1 irradiates the wafer is defined as a column. The exposure apparatus of this embodiment has nine columns (col.1 to col.9). The intermediate image of the electron source in the multi-source module 1 is formed by the magnetic lens of the magnetic lens array 21 and a corresponding magnetic lens of the magnetic lens array 22. Another intermediate image of the electron source is formed on the wafer 4 by the magnetic lens of the magnetic lens array 23 and a corresponding magnetic lens of the magnetic lens array 24. That is, the image of the electron source in the multi-source module 1 is projected on the wafer 4. By individually controlling the excitation conditions of the magnetic lens arrays 21, 22, 23, and 24 by the coils CC1, CC2, CC3, and CC4, the optical characteristics (focal position, image rotation, and magnification) of the columns can be adjusted almost uniformly (i.e., by the same amount). Each column has a main deflector 3. The main deflector 3 deflects a plurality of electron beams from a corresponding multi-source module 1, and displaces a plurality of electron source images in the X and Y directions on the wafer 4. The stage 5 can move the wafer 4 set on it in the X and Y directions perpendicular to an optical axis AX (Z-axis) and the rotation direction around the Z-axis. A stage reference plate 6 is fixed to the stage 5. A reflected-electron detector 7 detects reflected electrons generated when a mark on the stage reference plate 6 is irradiated with an electron beam. FIG. 2 is a sectional view showing one column in FIG. 1A in detail. The detailed arrangements of the multi-source module 1 and column will be explained with reference to FIG. 2. The multi-source module 1 has an electron gun (not shown) which forms an electron source (crossover image) 101. The flow of electrons radiated by the electron source 101 is changed into an almost collimated electron beam by a condenser lens 102. The condenser lens 102 of this embodiment is an electrostatic lens made up of three aperture electrodes. One almost collimated electron beam formed through the condenser lens 102 enters an aperture array 103 formed by two-dimensionally arraying a plurality of apertures. The electron beam passes through the plurality of apertures. A plurality of electron beams having passed through the aperture array 103 pass through a lens array 104 formed by two-dimensionally arraying electrostatic lenses having the same optical power. The electron beams pass through deflector arrays 105 and 106 each formed by two-dimensionally arraying individually drivable electrostatic octupole deflectors. The electron beams further pass through a blanker array 107 formed by two-dimensionally arraying individually drivable electrostatic blankers. FIG. 3 is an enlarged view showing part of the multi-source module 1. The function of each portion of the multi-source module 1 will be explained with reference to FIG. 3. An almost collimated electron beam formed by the condenser lens 102 is split into a plurality of electron beams by the aperture array 103 having a plurality of apertures. The split electron beams form the intermediate images of the electron source on corresponding blankers (more accurately, between blanker electrodes) of the blanker array 107 via the electrostatic lenses of a corresponding lens array 104. The deflectors of the deflector arrays 105 and 106 have a function of individually adjusting the position (position within a plane perpendicular to the optical axis AX) of the intermediate image of the electron source formed at the position of a corresponding blanker on the blanker array 107. An electron beam deflected by each blanker of the blanker array 107 is cut off by a blanking aperture AP in FIG. 2, and does not enter the wafer 4. An electron beam not deflected by the blanker array 107 is not cut off by the blanking aperture AP, and enters the wafer 4. In other words, a desired pattern can be drawn on the wafer 4 by individually controlling whether to allow a plurality of electron beams to enter the wafer 4 by a plurality of blankers of the blanker array 107 while a plurality of electron beams are deflected by the main deflector 3. Referring back to FIG. 2, a plurality of intermediate images of the electron source formed by each multi-source module 1 are projected on the wafer 4 via corresponding four magnetic lenses (four magnetic lenses of the same column) of the magnetic lens arrays 21, 22, 23, and 24. Of the optical characteristics of each column in projecting a plurality of intermediate images on the wafer 4, the image rotation and magnification can be individually corrected by the deflector arrays 105 and 106 each having a plurality of independent deflectors for separately adjusting the position of each intermediate image on the blanker array 107 (i.e., the incident position of an electron beam on the magnetic lens array). That is, the deflector arrays 105 and 106 function as an electron-optic element for individually correcting the rotation and magnification of an image projected on the wafer 4 every column. The focal position of each column can be individually adjusted by dynamic focus lenses (electrostatic or magnetic lenses) 108 and 109 arranged for each column. That is, the dynamic focus lenses 108 and 109 function as an electron-optic element for individually correcting the focal position every column. FIG. 4 is a block diagram showing the system configuration of the electron beam exposure apparatus. Each blanker array control circuit 41 individually controls a plurality of blankers which constitute the blanker array 107. Each deflector array control circuit 42 individually controls a plurality of deflectors which constitute the deflector arrays 105 and 106. Each D_FOCUS control circuit 43 individually controls the dynamic focus lenses 108 and 109. Each main deflector control circuit 44 controls the main deflector 3. Each reflected-electron detection circuit 45 processes a signal from the reflected-electron detector 7. The blanker array control circuits 41, deflector array control circuits 42, D_FOCUS control circuits 43, main deflector control circuits 44, and reflected-electron detection circuits 45 are equipped by the same number as the columns (nine columns col.1 to col.9). A magnetic lens array control circuit 46 controls the common coils CC1, CC2, CC3, and CC4 of the magnetic lens arrays 21, 22, 23, and 24. A stage driving control circuit 47 drives and controls the stage 5 in cooperation with a laser interferometer (not shown) which detects the position of the stage 5. A main control system 48 controls the above control circuits and manages the overall electron beam exposure apparatus. (Description of Optical Characteristic Adjustment Method) In the electron beam exposure apparatus of this embodiment, the electron-optic characteristics of a plurality of magnetic lenses which constitute the magnetic lens array are slightly different from each other owing to nonuniformity in the permeability and aperture shape of the magnetic disk. For example, different image rotations and magnifications of columns result in actual incident positions of electron beams on the wafer, as shown in FIG. 5 (incident positions are exaggerated in FIG. 5). In other words, the electron-optic characteristics (focal position, image rotation, magnification, and the like) change between columns. As a method which solves this problem, an electron-optic characteristic adjustment method in the electron beam exposure apparatus according to the preferred embodiment of the present invention will be described. The main control system 48 executes electron-optic characteristic adjustment processing as shown in FIG. 6. The main control system 48 executes electron-optic characteristic adjustment processing in consideration of a change in the electron-optic characteristic of the column over time and a change in the target value of the electron-optic characteristic, e.g., every time the pattern to be drawn on the wafer is changed (i.e., every time the job is changed). The respective steps will be explained below. In step S101, in order to detect the focal position of an electron beam on the wafer that represents each column (in this case, an electron beam at the center out of a plurality of electron beams of each column), the main control system 48 instructs the blanker array control circuit 41 to control the blanker array 107 which allows only an electron beam selected as a focal position detection target to enter the wafer 4. At this time, the stage 5 is moved in advance by the stage driving control circuit 47 to locate the reference mark of the reference plate 6 near the irradiation position of the selected electron beam. The main control system 48 instructs the D_FOCUS control circuit 43 to oscillate the focal position of the electron beam by the dynamic focus lens 108 and/or 109. The main control system 48 instructs the main deflector control circuit 44 to scan the reference mark with the selected electron beam. The main control system 48 obtains, from the reflected-electron detection circuit 45, information about electrons reflected by the reference mark. As a result, the main control system 48 detects the current focal position of the electron beam. In step S101, this processing is executed for all electron beams which represent respective columns. In step S102, as shown in FIG. 7A, the main control system 48 detects a maximum position (MAXP) and minimum position (MINP) from actual focal positions detected for electron beams which represent respective columns, and determines an intermediate position (CP). In step S103, the main control system 48 instructs the magnetic lens array control circuit 46 to adjust the common coils of the magnetic lens arrays 21, 22, 23, and 24 and move their focal positions by almost the same amount for all the columns so as to set the intermediate position (CP) to a target position (TP). The result is shown in FIG. 7B. More specifically, the maximum value (xcex4max) of the difference between the target position and the actual focal position of each column is minimized. In the next step, the adjustment amount by the dynamic focus lenses 108 and 109 serving as focal position correction units arranged for each column can be minimized. This means that the plurality of focal position correction units 108 and 109 arranged for each column can be downsized and their interference can be minimized. In step S104, the main control system 48 causes the dynamic focus lenses 108 and 109 to adjust the focal position so as to make the focal position coincide with the target position for each column on the basis of the difference between the target position and the actual focal position of each column as shown in FIG. 7B. In step S105, the main control system 48 instructs the blanker array control circuit 41 to allow only the selected electron beam to enter the wafer in order to detect the incident position of each electron beam on the wafer. At this time, the stage 5 is moved in advance by the stage driving control circuit 47 to locate the reference mark of the reference plate 6 at the ideal irradiation position (design irradiation position) of the selected electron beam. The main control system 48 instructs the main deflector control circuit 44 to scan the reference mark with the selected electron beam. The main control system 48 obtains, from the reflected-electron detection circuit 45, information about electrons reflected by the reference mark. Hence, the main control system 48 can detect the current irradiation position of the electron beam. In step S105, this processing is executed for all electron beams. Based on the actual electron beam irradiation position for each column, the main control system 48 obtains the image rotation/magnification of the column. In step S106, as shown in FIG. 8A, the main control system 48 detects a maximum value (MAXV) and minimum value (MINV) from image rotations/magnifications obtained for respective columns, and determines an intermediate value (CV). In step S107, the main control system 48 instructs the magnetic lens array control circuit 46 to adjust the common coils of the magnetic lens arrays 21, 22, 23, and 24 and move their image rotations/magnifications (without changing the focal positions) by almost the same amount for all the columns so as to set the intermediate value (CV) to a target value (TV). The result is shown in FIG. 8B. More specifically, the maximum value (xcex4max) of the difference between the target value and the actual image rotation/magnification of each column is minimized. In the next step, the adjustment amount by the deflector arrays 105 and 106 serving as an image rotation/magnification correction unit arranged for each column can be minimized. This means that a plurality of deflectors which constitute each of the deflector arrays 105 and 106 serving as the image rotation/magnification correction unit arranged for each column can be downsized and the interference between the deflectors can be reduced. In step S108, the main control system 48 causes the deflector arrays 105 and 106 serving as the image rotation/magnification correction unit to adjust the image rotation/magnification so as to make the image rotation/magnification coincide with the target value for each column on the basis of the difference between the target value and the actual image rotation/magnification of each column as shown in FIG. 8B. At this time, the image rotation/magnification is corrected by individually controlling a plurality of deflectors which constitute each of the deflector arrays 105 and 106. (Device Manufacturing Method) An embodiment of a device manufacturing method using the above-described electron beam exposure apparatus will be described. FIG. 9 is a flow chart showing the manufacturing flow of a microdevice (semiconductor chip such as an IC or LSI, a liquid crystal panel, a CCD, a thin-film magnetic head, a micromachine, or the like). In step 1 (circuit design), a semiconductor device circuit is designed. In step 2 (exposure control data formation), exposure control data for the exposure apparatus is formed on the basis of a designed circuit pattern. In step 3 (wafer formation), a wafer is formed using a material such as silicon. In step 4 (wafer process) called a pre-process, an actual circuit is formed on the wafer by lithography using the wafer and the exposure apparatus to which the prepared exposure control data is input. Step 5 (assembly) called a post-process is the step of forming a semiconductor chip by using the wafer formed in step 4, and includes an assembly process (dicing and bonding) and packaging process (chip encapsulation). In step 6 (inspection), the semiconductor device manufactured in step 5 undergoes inspections such as an operation confirmation test and durability test. After these steps, the semiconductor device is completed and shipped (step 7). FIG. 10 shows the detailed flow of the wafer process. In step 11 (oxidation), the wafer surface is oxidized. In step 12 (CVD), an insulating film is formed on the wafer surface. In step 13 (electrode formation), an electrode is formed on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted in the wafer. In step 15 (resist processing), a photosensitive agent is applied to the wafer. In step 16 (exposure), a circuit pattern is drawn on the wafer by the above-mentioned exposure apparatus exposes. Prior to exposure processing, the exposure apparatus adjusts the focal position by the above method every column, and adjusts the image rotation and magnification every column. In step 17 (developing), the exposed wafer is developed. In step 18 (etching), the resist is etched except the developed resist image. In step 19 (resist removal), an unnecessary resist after etching is removed. These steps are repeated to form multiple circuit patterns on the wafer. This manufacturing method enables manufacturing a highly integrated semiconductor device at low cost, which has conventionally been difficult to manufacture. The present invention can accurately correct the electron-optic characteristics of a plurality of magnetic lenses which constitute a magnetic lens array. As many apparently widely different embodiments of the present invention can be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments thereof except as defined in the claims. |
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052215148 | summary | BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is generally related to guide pins for a nuclear reactor fuel assembly and more particularly to the replacement of existing guide pins. 2. General Background In commercial nuclear reactors fuel guide pins extend down from the upper core plate into guide tubes in the fuel assemblies This aids in maintaining proper alignment of the fuel assemblies with the pressure vessel so that the control rods operate properly. During initial construction of the reactor each guide pin is inserted into a bore in the upper core plate from the bottom of the plate and threadably secured with a nut at the top of the core plate. The nut is then welded to the pin to prevent loosening during service. After construction is completed and operation begun, fuel guide pins may need to be replaced due to a defect or the fuel guide pin becoming bent. A problem encountered in replacing fuel guide pins is that the top of the upper core plate is very difficult to access. This makes removal of the nut from the top of the core plate very difficult and time consuming. SUMMARY OF THE INVENTION The present invention addresses the above problem in a straightforward manner. What is provided is a method and apparatus where the existing pin is removed by cutting it near the bottom of the upper core plate. A removal process such as EDM (electrical discharge machining) is then used to remove that portion of the pin remaining within the plate to a level slightly below its retaining nut. The removal process is continued to bore a hole through the remaining part of the pin. A replacement pin is then inserted into the plate from the bottom and through the hole in the remaining part of the original pin. The replacement pin has a collet lock with a tapered shoulder at its upper and that allows it to go through the hole in the original pin but not to come back out. The replacement pin body is provided with a bore to receive the collet lock. A bolt fits through the replacement pin body and threadably engages the collet, spreads the tapered shoulder, and secures the replacement pin and the remaining portion of the original pin and its retaining nut in position. |
048329010 | claims | 1. A method for straightening a bent mixing vane of a grid in a fuel cell of a nuclear reactor, comprising: (a) introducing a member having means movable between a first open position and a second closed position, into the fuel cell with the means in the second closed position and being below the grid with the bent mixing vane; (b) moving the means into the first open position; and (c) partially withdrawing the member axially from the fuel cell such that the means contacts and straightens the bent mixing vane and carries a reaction load to the grid. (d) moving the means into the second closed position. (e) extracting the member from the fuel cell. (f) detecting that the mixing vane is straightened. (a) introducing a member having a first means movable between a first open position and a second closed position, and actuatable second means for moving the first movable means between the first and second positions, into the fuel cell with the first means in the second closed position and being below the grid with the bent mixing vane; (b) actuating the second means to move the first means into the first open position; and (c) partially withdrawing the member axially from the fuel cell such that the first means contacts and straightens the bent mixing vane and carries a reaction load to the grid. (d) actuating the second means to move the first means into the second closed position. (e) extracting the member from the fuel cell. (f) remotely detecting that the mixing vane is straightened. (a) remotely detecting that the mixing vane is bent; (b) introducing a member having a means movable between a first open position and a second closed position, and actuatable second means for moving the first movable means between the first and second positions, into the fuel cell with the first means in the second closed position and being below the grid with the bent mixing vane; (c) actuating the second means to move the first means into the first open position; and (d) partially withdrawing the member from the fuel cell such that the first means contacts and straightens the bent mixing vane, wherein the step of remotely detecting includes the substeps of: (a) introducing a member having means movable between a first open position and a second closed position, and actuatable second means for moving the first movable means between the first and second positions, into the fuel cell with the first means in the second closed position and being below the grid with the bent mixing vane; (b) actuating the second means to move the first means into the first open position; (c) partially withdrawing the member from the fuel cell such that the first means contacts and straightens the bent mixing vane; and (d) monitoring and raising load on the member, wherein steps (c) and (d) are performed contemporaneously. (a) introducing a member having means movable between a first open position and a second closed position, into the external fuel cell with the means in the second closed position and being below the grid with the bent mixing vane; (b) moving the means into the first open position; (c) partially withdrawing the member from the grid while monitoring and raising load on the member such that the means contacts and straightens the bent mixing vane; (d) reducing the load on the member to static weight thereof; (e) slightly lowering the member; (f) moving the means into the second closed position; and (g) extracting the member from the fuel cell. 2. The method as recited in claim 1, wherein step (a) is preceded by the step of remotely detecting that the mixing vane is bent. 3. The method as recited in claim 1, wherein step (c) is followed by the step of: 4. The method as recited in claim 3, wherein step (d) is followed by the step of: 5. The method as recited in claim 4, wherein step (e) is followed by the step of: 6. A method for straightening a bent mixing vane of a grid in a fuel cell of a nuclear reactor, comprising: 7. The method as recited in claim 6, wherein step (c) is followed by the step of: 8. The method as recited in claim 7, wherein step (d) is followed by the step of: 9. The method as recited in claim 8, wherein step (e) is followed by the step of: 10. The method as recited in claim 6, wherein step (a) is preceded by the step of remotely detecting that the mixing vane is bent. 11. A method for straightening a bent mixing vane of a grid in a fuel cell of a nuclear reactor, comprising: 12. A method for straightening a bent mixing vane of a grid in a fuel cell of a nuclear reactor, comprising: 13. A method for straightening a bent mixing vane of a grid in an external fuel cell of a nuclear reactor, comprising: |
058898310 | abstract | A containment of a nuclear power station includes a device for igniting hydrogen contained in a hydrogen/air mixture. A central electrode for lightning flash generation is provided to ensure the maintenance of a particularly low hydrogen concentration in the entire interior of the containment. The central electrode is connected to a high-voltage source for generating a high voltage greater than the disruptive discharge voltage of air. |
description | This application is a continuation of U.S. patent application Ser. No. 15/432,724 filed Feb. 14, 2017, which is a continuation-in-part of U.S. patent application Ser. No. 15/402,739 filed Jan. 10, 2017, which is a continuation-in-part of U.S. patent application Ser. No. 15/348,625 filed Nov. 10, 2016, which is a continuation-in-part of U.S. patent application Ser. No. 15/167,617 filed May 27, 2016, which is a continuation-in-part of U.S. patent application Ser. No. 15/152,479 filed May 11, 2016, which is a continuation-in-part of U.S. patent application Ser. No. 14/216,788 filed Mar. 17, 2014, which is a continuation-in-part of U.S. patent application Ser. No. 13/087,096 filed Apr. 14, 2011, which claims benefit of U.S. provisional patent application No. 61/324,776 filed Apr. 16, 2010, all of which are incorporated herein in their entirety by this reference thereto. Field of the Invention The invention relates generally to imaging and treating a tumor. Discussion of the Prior Art Cancer Treatment Proton therapy works by aiming energetic ionizing particles, such as protons accelerated with a particle accelerator, onto a target tumor. These particles damage the DNA of cells, ultimately causing their death. Cancerous cells, because of their high rate of division and their reduced ability to repair damaged DNA, are particularly vulnerable to attack on their DNA. Patents related to the current invention are summarized here. Proton Beam Therapy System F. Cole, et. al. of Loma Linda University Medical Center “Multi-Station Proton Beam Therapy System”, U.S. Pat. No. 4,870,287 (Sep. 26, 1989) describe a proton beam therapy system for selectively generating and transporting proton beams from a single proton source and accelerator to a selected treatment room of a plurality of patient treatment rooms. Imaging Lomax, A., “Method for Evaluating Radiation Model Data in Particle Beam Radiation Applications”, U.S. Pat. No. 8,461,559 B2 (Jun. 11, 2013) describes comparing a radiation target to a volume with a single pencil beam shot to the targeted volume. P. Adamee, et. al. “Charged Particle Beam Apparatus and Method for Operating the Same”, U.S. Pat. No. 7,274,018 (Sep. 25, 2007) and P. Adamee, et. al. “Charged Particle Beam Apparatus and Method for Operating the Same”, U.S. Pat. No. 7,045,781 (May 16, 2006) describe a charged particle beam apparatus configured for serial and/or parallel imaging of an object. K. Hiramoto, et. al. “Ion Beam Therapy System and its Couch Positioning System”, U.S. Pat. No. 7,193,227 (Mar. 20, 2007) describe an ion beam therapy system having an X-ray imaging system moving in conjunction with a rotating gantry. C. Maurer, et. al. “Apparatus and Method for Registration of Images to Physical Space Using a Weighted Combination of Points and Surfaces”, U.S. Pat. No. 6,560,354 (May 6, 2003) described a process of X-ray computed tomography registered to physical measurements taken on the patient's body, where different body parts are given different weights. Weights are used in an iterative registration process to determine a rigid body transformation process, where the transformation function is used to assist surgical or stereotactic procedures. M. Blair, et. al. “Proton Beam Digital Imaging System”, U.S. Pat. No. 5,825,845 (Oct. 20, 1998) describe a proton beam digital imaging system having an X-ray source that is movable into a treatment beam line that can produce an X-ray beam through a region of the body. By comparison of the relative positions of the center of the beam in the patient orientation image and the isocentre in the master prescription image with respect to selected monuments, the amount and direction of movement of the patient to make the best beam center correspond to the target isocentre is determined. S. Nishihara, et. al. “Therapeutic Apparatus”, U.S. Pat. No. 5,039,867 (Aug. 13, 1991) describe a method and apparatus for positioning a therapeutic beam in which a first distance is determined on the basis of a first image, a second distance is determined on the basis of a second image, and the patient is moved to a therapy beam irradiation position on the basis of the first and second distances. Problem There exists in the art of charged particle cancer therapy a need for accurate, precise, and rapid imaging of a patient and/or treatment of a tumor using charged particles in a complex room setting. The invention comprises a multi-axes/multi-probe type imaging apparatus and method of use thereof. Elements and steps in the figures are illustrated for simplicity and clarity and have not necessarily been rendered according to any particular sequence. For example, steps that are performed concurrently or in different order are illustrated in the figures to help improve understanding of embodiments of the present invention. The invention comprises a method and apparatus for treating a tumor with positively charged particles using multiple beamline positions not having an isocenter. For example, a method for treating a tumor of a patient in a treatment room with positively charged particles, includes the steps of: (1) delivering the positively charged particles from a synchrotron along a beam transport path, the beam transport path redirectable as a function of time to yield a plurality of incident vectors, each of the plurality of incident vectors directed toward the treatment room and (2) redirecting portions of the positively charged particles traveling along each of the plurality of incident vectors, with an output nozzle of the beam transport path, to the tumor, where a first vector, of the plurality of incident vectors, comprises a first direction intersecting the tumor and where a second vector, of the plurality of incident vectors, comprises a second direction passing by the tumor without entering the tumor. Optionally and preferably, the step of redirecting (1) directs a first portion of the positively charged particles traveling along the first incident vector to a first tumor treatment path intersecting a front of the tumor and (2) directs a second portion of the positively charged particles traveling along the second incident vector to a second tumor treatment path intersecting at least one of a side of the tumor and a back of the tumor relative to the front of the tumor. In combination, the above described embodiment is used with an X-ray imaging and charged particle beam treatment or imaging system comprising the steps of: rotating an X-ray imaging system, configured to deliver the X-rays, around both a first rotation axis and the patient; imaging the patient using X-rays from the X-ray imaging system; and passing the positively charged particles through an exit port of a nozzle system, the nozzle system connected to a synchrotron via a first beam transport line, the positively charged particles passing into the patient from the exit port along a z-axis and at least one of: (1) treating the tumor with the positively charged particles and (2) imaging the patient with residual charged particles comprising the positively charged particles after transmitting through the patient. In one case, a first cone beam X-ray source and a second cone beam X-ray source are positioned on a first side of the patient and at least one two-dimensional X-ray detector is positioned on an opposite side of the patient from the first cone beam X-ray source. In combination, the above described embodiment is used with a multiplexed proton tomography imaging apparatus and method of use thereof. For example, a method for imaging a tumor of a patient comprises the steps of: (1) simultaneously detecting spatially resolved positively charged particle positions passing through each of a set of cross-section planes, where the cross-section planes are both prior to and posterior to the patient along a path of the positively charged particles; (2) determining a prior vector for each of the individual positively charged particles entering a patient using the detected positions; (3) determining a posterior vector for each of the individual positively charged particles exiting the patient using the detected positions; (4) generating a path, a best path, and/or a probable path of each positively charged particle through the patient; and (5) generating an image of the patient using the n probable proton paths. In one case, an imaging system: (1) delivers a set of n protons from a synchrotron: through a beam transport system exit nozzle, through a proton radial cross-section beam expander, through a first prior imaging sheet, through a second prior imaging sheet, through a patient position, through at least one posterior imaging sheet, and into a scintillation material of a beam energy scintillation detector system, where the first prior imaging sheet is positioned between the proton radial cross-section beam expander and the patient position, where the second prior imaging sheet is positioned between the proton radial cross-section beam expander and the patient position; (2) simultaneously detects spatially resolved both prior and posterior position photon emissions, resultant from passage of multiple protons; (4) determines both a prior vector and a posterior vector for each proton; and (5) determines a path for each proton through the patient and uses the determined paths, optionally and preferably with residual energy determinations, to generate an image of the patient. In combination, a method of double exposure imaging of a tumor of a patient is performed using hardware, using a detector responsive to both X-rays and positively charged particles, simultaneously, and/or in either order. The preferably near-simultaneous double exposure yields enhanced resolution due to the imaging rate versus patient movement, no requirement of a software overlay step, and associated errors, of the X-ray based image and the positively charged particle based image, and enhancement of an X-ray image, the enhancement resultant from a differing physical interaction of the positively charged particles with the patient compared to interactions of X-rays and the patient. Further, resolution enhancements utilize individual particle tracking, as measured using detection screens, to determine a probable intra-patient path. Optionally, residual energy positively charged particles, having passed through a primarily X-ray detector, are used to generate a second/dual image at a secondary detector, such as a detector based on scintillation resultant from proton absorbance. In combination, a method for imaging a tumor of a patient using X-rays and positively charged particles comprises the steps of: (1) generating an X-ray image using the X-rays directed from an X-ray source, through the patient, and to an X-ray detector, (2) generating a positively charged particle image: (a) using the positively charged particles directed from an exit nozzle, through the patient, through the X-ray detector, and to a scintillator, the scintillator emitting photons when struck by the positively charged particles and (b) generating the positively charged particle image of the tumor using a photon detector configured to detect the emitted photons, where the X-ray detector maintains a static position between said the nozzle and the scintillator during the step of generating a positively charged particle image. Individual images are optionally and preferably collected as a function of relative rotation of the patient and the imaging elements to form a three-dimensional image, such as via tomography. In combination, a method and apparatus is described for determining a position of a tumor in a patient for treatment of the tumor using positively charged particles in a treatment room. More particularly, the method and apparatus use a set of fiducial markers and fiducial detectors to mark/determine relative position of static and/or moveable objects in a treatment room using photons passing from the markers to the detectors. Further, position and orientation of at least one of the objects is calibrated to a reference line, such as a zero-offset beam treatment line passing through an exit nozzle, which yields a relative position of each fiducially marked object in the treatment room. Treatment calculations are subsequently determined using the reference line and/or points thereon. The inventor notes that the treatment calculations are optionally and preferably performed without use of an isocenter point, such as a central point about which a treatment room gantry rotates, which eliminates mechanical errors associated with the isocenter point being an isocenter volume in practice. For example, a set of fiducial marker detectors detect photons emitted from and/or reflected off of a set of fiducial markers positioned on one or more objects in a treatment room and resultant determined distances and/or calculated angles are used to determine relative positions of multiple objects or elements in the treatment room. Generally, in an iterative process, at a first time objects, such as a treatment beamline output nozzle, a specific portion of a patient relative to a tumor, a scintillation detection material, an X-ray system element, and/or a detection element, are mapped and relative positions and/or angles therebetween are determined. At a second time, the position of the mapped objects is used in: (1) imaging, such as X-ray, positron emission tomography, and/or proton beam imaging and/or (2) beam targeting and treatment, such as positively charged particle based cancer treatment. As relative positions of objects in the treatment room are dynamically determined using the fiducial marking system, engineering and/or mathematical constraints of a treatment beamline isocenter is removed. In combination, a method and apparatus for imaging a tumor of a patient using positively charged particles, comprising the steps of: (1) sequentially delivering from an output nozzle, connected to a first beam transport line, to the patient: a first set of the positively charged particles comprising a first mean energy and a second set of the positively charged particles comprising a second mean energy, the second mean energy at least two mega electron Volts different from the first mean energy; (2) after transmission through the patient, sequentially detecting: a first residual energy of the first set of the positively charged particles and a second residual energy of the second set of the positively charged particles; and (3) determining a water equivalent thickness of a probed path of the patient using the first residual energy and the second residual energy. The detection step optionally uses a scintillation material and/or an X-ray detector material to detect the residual energy positively charged particles. Use of a half-maximum of a Gaussian fit to output of the detection material as a function of energy, preferably using three of more detected residual energies, yields a water equivalent thickness of the sampled beam path. In combination, an apparatus and method of use thereof are used for directing positively charged particle beams into a patient from several directions. In one example, a charged particle delivery system, comprising: a controller, an accelerator, a beam path switching magnet, a primary beam line from the accelerator to the path switching magnet, and a plurality of physically separated beam transport lines from the beam path switching magnet to a single patient treatment position is used, where the controller and beam switching magnet are used to direct sets of the positively charged particles through alternatingly selected beam transport lines to the patient, tumor, and/or an imaging detector. Optionally, during a single session and at separate times, a single repositionable treatment nozzle is repositioned to interface with each beam transport line, such as to a terminus of each beam transport line, which allows the charged particle delivery system to use one and/or fewer beam output nozzles that are moved with nozzle gantries. A single nozzle with first and second axis scanning capability along with beam transport lines leading to various sides of a patient allow the charged particle delivery system to operate without movement and/or rotation of a beam transport gantry and an associated beam transport gantry. Beam transport line gantries are optional as one or more of the beam transport lines are preferably statically positioned. In combination, a beam adjustment system is used to perform energy adjustments on circulating charged particles in a synchrotron previously accelerated to a starting energy with a traditional accelerator of the synchrotron or related devices, such as a cyclotron. The beam adjustment system uses a radio-frequency modulated potential difference applied along a longitudinal path of the circulating charged particles to accelerate or decelerate the circulating charged particles. Optionally, the beam adjustment system phase shifts the applied radio-frequency field to accelerate or decelerate the circulating charged particle while spatially longitudinally tightening a grouped bunch of the circulating charged particles. The beam adjustment system facilitates treating multiple layers or depths of the tumor between the slow step of reloading the synchrotron. Optionally, the potential differences across a gap described herein are used to accelerate or decelerate the charged particle after extraction from the synchrotron without use of the radio-frequency modulation. In combination, an imaging system, such as a positron emission tracking system, optionally used to control the beam adjustment system, is used to: dynamically determine a treatment beam position, track a history of treatment beam positions, guide the treatment beam, and/or image a tumor before, during, and/or after treatment with the charged particle beam. In combination, an imaging system translating on a linear path past a patient operates alternatingly with and/or during a gantry rotating a treatment beam around the patient. More particularly, a method for both imaging a tumor and treating the tumor of a patient using positively charged particles includes the steps of: (1) rotating a gantry support and/or gantry, connected to at least a portion of a beam transport system configured to pass a charged particle treatment beam, circumferentially about the patient and a gantry rotation axis; (2) translating a translatable imaging system past the patient on a path parallel to an axis perpendicular to the gantry rotation axis; (3) imaging the tumor using the translatable imaging system; and (4) treating the tumor using the treatment beam. In combination, a method for imaging and treating a tumor of a patient with positively charged particles, comprises the steps of: (1) using a rotatable gantry support to support and rotate a section of a positively charged particle beam transport line about a rotation axis and a tumor of a patient; (2) using a rotatable and optionally extendable secondary support to support, circumferentially position, and laterally position a primary and optional secondary imaging system about the tumor; (3) image the tumor using the primary and optional secondary imaging system as a function of rotation and/or translation of the secondary support; and (4) treat, optionally concurrently, the tumor using the positively charged particles as a function of circumferential position of the section of the charged particle beam about the tumor. In combination, a method and apparatus for imaging a tumor of a patient using positively charged particles and X-rays, comprises the steps of: (1) transporting the positively charged particles from an accelerator to a patient position using a beam transport line, where the beam transport line comprises a positively charged particle beam path and an X-ray beam path; (2) detecting scintillation induced by the positively charged particles using a scintillation detector system; (3) detecting X-rays using an X-ray detector system; (4) positioning a mounting rail through linear extension/retraction to: at a first time and at a first extension position of the mounting rail, position the scintillation detector system opposite the patient position from the exit nozzle and at a second time and at a second extension position of the mounting rail, position the X-ray detector system opposite the patient position from the exit nozzle; (5) generating an image of the tumor using output of the scintillation detector system and the X-ray detector system; and (6) alternating between the step of detecting scintillation and treating the tumor via irradiation of the tumor using the positively charged particles. In combination, a method or apparatus for tomographically imaging a sample, such as a tumor of a patient, using positively charged particles is described. Position, energy, and/or vectors of the positively charged particles are determined using a plurality of scintillators, such as layers of chemically distinct scintillators where each chemically distinct scintillator emits photons of differing wavelengths upon energy transfer from the positively charged particles. Knowledge of position of a given scintillator type and a color of the emitted photon from the scintillator type allows a determination of residual energy of the charged particle energy in a scintillator detector. Optionally, a two-dimensional detector array additionally yields x/y-plane information, coupled with the z-axis energy information, about state of the positively charged particles. State of the positively charged particles as a function of relative sample/particle beam rotation is used in tomographic reconstruction of an image of the sample or the tumor. In another example, a method or apparatus for tomographic imaging of a tumor of a patient using positively charged particles respectively positions a plurality of two-dimensional detector arrays on multiple surfaces of a scintillation material or scintillator. For instance, a first two-dimensional detector array is optically coupled to a first side or surface of a scintillation material, a second two-dimensional detector array is optically coupled to a second side of the scintillation material, and a third two-dimensional detector array is optically coupled to a third side of the scintillation material. Secondary photons emitted from the scintillation material, resultant from energy transfer from the positively charged particles, are detected by the plurality of two-dimensional detector arrays, where each detector array images the scintillation material. Combining signals from the plurality of two-dimensional detector arrays, the path, position, energy, and/or state of the positively charged particle beam as a function of time and/or rotation of the patient relative to the positively charged particle beam is determined and used in tomographic reconstruction of an image of the tumor in the patient or a sample. Particularly, a probabilistic pathway of the positively charged particles through the sample, which is altered by sample constituents, is constrained, which yields a higher resolution, a more accurate and/or a more precise image. In another example, a scintillation material is longitudinally packaged in a circumferentially surrounding sheath, where the sheath has a lower index of refraction than the scintillation material. The scintillation material yields emitted secondary photons upon passage of a charged particle beam, such as a positively charged residual particle beam having transmitted through a sample. The internally generated secondary photons within the sheath are guided to a detector element by the difference in index of refraction between the sheath and the scintillation material, similar to a light pipe or fiber optic. The coated scintillation material or fiber is referred to herein as a scintillation optic. Multiple scintillation optics are assembled to form a two-dimensional scintillation array. The scintillation array is optionally and preferably coupled to a detector or two-dimensional detector array, such as via a coupling optic, an array of focusing optics, and/or a color filter array. In combination, an ion source is coupled to the apparatus. The ion source extraction system facilitates on demand extraction of charged particles at relatively low voltage levels and from a stable ion source. For example, a triode extraction system allows extraction of charged particles, such as protons, from a maintained temperature plasma source, which reduces emittance of the extracted particles and allows use of lower, more maintainable downstream potentials to control an ion beam path of the extracted ions. The reduced emittance facilitates ion beam precision in applications, such as in imaging, tumor imaging, tomographic imaging, and/or cancer treatment. In combination, a state of a charged particle beam is monitored and/or checked, such as against a previously established radiation plan, in a position just prior to the beam entering the patient. In one example, the charged particle beam state is measured after a final manipulation of intensity, energy, shape, and/or position, such as via use of an insert, a range filter, a collimator, an aperture, and/or a compensator. In one case, one or more beam crossing elements, sheets, coatings, or layers, configured to emit photons upon passage therethrough by the charged particle beam, are positioned between the final manipulation apparatus, such as the insert, and prior to entry into the patient. In combination, a patient specific tray insert is inserted into a tray frame to form a beam control tray assembly, the beam control tray assembly is inserted into a slot of a tray receiver assembly, and the tray assembly is positioned relative to a gantry nozzle. Optionally, multiple tray inserts, each used to control a beam state parameter, are inserted into slots of the tray receiver assembly. The beam control tray assembling includes an identifier, such as an electromechanical identifier, of the particular insert type, which is communicated to a main controller, such as via the tray receiver assembly. Optionally and preferably, a hand control pendant is used in loading and/or positioning the tray receiver assembly. In combination, a gantry positions both: (1) a section of a beam transport system, such as a terminal section, used to transport and direct positively charged particles to a tumor and (2) at least one imaging system. In one case, the imaging system is orientated on a same axis as the positively charged particle, such as at a different time through rotation of the gantry. In another case, the imaging system uses at least two crossing beamlines, each beamline coupled to a respective detector, to yield multiple views of the patient. In another case, one or more imaging subsystem yields a two-dimensional image of the patient, such as for position confirmation and/or as part of a set of images used to develop a three-dimensional image of the patient. In combination, multiple linked control stations are used to control position of elements of a beam transport system, nozzle, and/or patient specific beam shaping element relative to a dynamically controlled patient position and/or an imaging surface, element, or system. In combination, a tomography system is optionally used in combination with a charged particle cancer therapy system. The tomography system uses tomography or tomographic imaging, which refers to imaging by sections or sectioning through the use of a penetrating wave, such as a positively charge particle from an injector and/or accelerator. Optionally and preferably, a common injector, accelerator, and beam transport system is used for both charged particle based tomographic imaging and charged particle cancer therapy. In one case, an output nozzle of the beam transport system is positioned with a gantry system while the gantry system and/or a patient support maintains a scintillation plate of the tomography system on the opposite side of the patient from the output nozzle. In another example, a charged particle state determination system, of a cancer therapy system or tomographic imaging system, uses one or more coated layers in conjunction with a scintillation material, scintillation detector and/or a tomographic imaging system at time of tumor and surrounding tissue sample mapping and/or at time of tumor treatment, such as to determine an input vector of the charged particle beam into a patient and/or an output vector of the charged particle beam from the patient. In another example, the charged particle tomography apparatus is used in combination with a charged particle cancer therapy system. For example, tomographic imaging of a cancerous tumor is performed using charged particles generated with an injector, accelerator, and guided with a delivery system. The cancer therapy system uses the same injector, accelerator, and guided delivery system in delivering charged particles to the cancerous tumor. For example, the tomography apparatus and cancer therapy system use a common raster beam method and apparatus for treatment of solid cancers. More particularly, the invention comprises a multi-axis and/or multi-field raster beam charged particle accelerator used in: (1) tomography and (2) cancer therapy. Optionally, the system independently controls patient translation position, patient rotation position, two-dimensional beam trajectory, delivered radiation beam energy, delivered radiation beam intensity, beam velocity, timing of charged particle delivery, and/or distribution of radiation striking healthy tissue. The system operates in conjunction with a negative ion beam source, synchrotron, patient positioning, imaging, and/or targeting method and apparatus to deliver an effective and uniform dose of radiation to a tumor while distributing radiation striking healthy tissue. In combination, a treatment delivery control system (TDCS) or main controller is used to control multiple aspects of the cancer therapy system, including one or more of: an imaging system, such as a CT or PET; a positioner, such as a couch or patient interface module; an injector or injection system; a radio-frequency quadrupole system; a ring accelerator or synchrotron; an extraction system; an irradiation plan; and a display system. The TDCS is preferably a control system for automated cancer therapy once the patient is positioned. The TDCS integrates output of one or more of the below described cancer therapy system elements with inputs of one or more of the below described cancer therapy system elements. More generally, the TDCS controls or manages input and/or output of imaging, an irradiation plan, and charged particle delivery. In combination, one or more trays are inserted into the positively charged particle beam path, such as at or near the exit port of a gantry nozzle in close proximity to the patient. Each tray holds an insert, such as a patient specific insert for controlling the energy, focus depth, and/or shape of the charged particle beam. Examples of inserts include a range shifter, a compensator, an aperture, a ridge filter, and a blank. Optionally and preferably, each tray communicates a held and positioned insert to a main controller of the charged particle cancer therapy system. The trays optionally hold one or more of the imaging sheets configured to emit light upon transmission of the charged particle beam through a corresponding localized position of the one or more imaging sheets. For clarity of presentation and without loss of generality, throughout this document, treatment systems and imaging systems are described relative to a tumor of a patient. However, more generally any sample is imaged with any of the imaging systems described herein and/or any element of the sample is treated with the positively charged particle beam(s) described herein. Charged Particle Beam Therapy Throughout this document, a charged particle beam therapy system, such as a proton beam, hydrogen ion beam, or carbon ion beam, is described. Herein, the charged particle beam therapy system is described using a proton beam. However, the aspects taught and described in terms of a proton beam are not intended to be limiting to that of a proton beam and are illustrative of a charged particle beam system, a positively charged beam system, and/or a multiply charged particle beam system, such as C4+ or C6+. Any of the techniques described herein are equally applicable to any charged particle beam system. Referring now to FIG. 1A, a charged particle beam system 100 is illustrated. The charged particle beam preferably comprises a number of subsystems including any of: a main controller 110; an injection system 120; a synchrotron 130 that typically includes: (1) an accelerator system 131 and (2) an internal or connected extraction system 134; a beam transport system 135; a scanning/targeting/delivery system 140; a nozzle system 146; a patient interface module 150; a display system 160; and/or an imaging system 170. An exemplary method of use of the charged particle beam system 100 is provided. The main controller 110 controls one or more of the subsystems to accurately and precisely deliver protons to a tumor of a patient. For example, the main controller 110 obtains an image, such as a portion of a body and/or of a tumor, from the imaging system 170. The main controller 110 also obtains position and/or timing information from the patient interface module 150. The main controller 110 optionally controls the injection system 120 to inject a proton into a synchrotron 130. The synchrotron typically contains at least an accelerator system 131 and an extraction system 134. The main controller 110 preferably controls the proton beam within the accelerator system, such as by controlling speed, trajectory, and timing of the proton beam. The main controller then controls extraction of a proton beam from the accelerator through the extraction system 134. For example, the controller controls timing, energy, and/or intensity of the extracted beam. The controller 110 also preferably controls targeting of the proton beam through the scanning/targeting/delivery system 140 to the patient interface module 150. One or more components of the patient interface module 150, such as translational and rotational position of the patient, are preferably controlled by the main controller 110. Further, display elements of the display system 160 are preferably controlled via the main controller 110. Displays, such as display screens, are typically provided to one or more operators and/or to one or more patients. In one embodiment, the main controller 110 times the delivery of the proton beam from all systems, such that protons are delivered in an optimal therapeutic manner to the tumor of the patient. Herein, the main controller 110 refers to a single system controlling the charged particle beam system 100, to a single controller controlling a plurality of subsystems controlling the charged particle beam system 100, or to a plurality of individual controllers controlling one or more sub-systems of the charged particle beam system 100. Referring now to FIG. 39, the proton beam path 268 is directed to the treatment room 1222 along multiple paths. As illustrated, the proton beam path 268 is split/redirected using a plurality of beam path switching magnets 2810, such as the illustrated first beam switching magnet 2815 and the second beam switching magnet directing the protons along a first beam treatment line 2811 at a first time, t1, a second beam treatment line 2812 at a second time, t2, and a third beam treatment line 2813 at a third time, t3, where the number of paths from the synchrotron 130 to the treatment room 1222 comprises any number of paths. As illustrated, in a first case, a first mean unredirected beamline 2841 of the first beam treatment line 2811 optionally passes through a traditional isocenter 263 but not through the tumor 720, such as missing the tumor 720 by greater than 1, 2, 5, or 10 inches. In a second case, a second mean unredirected beamline 2842 of the second beam treatment line 2812 passes through the tumor 720 and subsequently passes through the isocenter 263. In a third case, a third unredirected beamline 2843 of the third treatment line 2813 does not pass through the tumor 720 or the isocenter 263, such as missing the tumor 720 and/or the isocenter 263 by greater than 1, 2, 3, 4, 5, 10, or 15 inches. However, as described in the next example, all voxels of the tumor 720 are treatable, despite a blocking element, using a combination of steering paths of the first, second, and/or third beamlines. Referring now to FIG. 1B, an example of a charged particle cancer therapy system 100 is provided. A main controller receives input from one, two, three, or four of a respiration monitoring and/or controlling controller 180, a beam controller 185, a rotation controller 147, and/or a timing to a time period in a respiration cycle controller 148. The beam controller 185 preferably includes one or more or a beam energy controller 182, the beam intensity controller 340, a beam velocity controller 186, and/or a horizontal/vertical beam positioning controller 188. The main controller 110 controls any element of the injection system 120; the synchrotron 130; the scanning/targeting/delivery system 140; the patient interface module 150; the display system 160; and/or the imaging system 170. For example, the respiration monitoring/controlling controller 180 controls any element or method associated with the respiration of the patient; the beam controller 185 controls any of the elements controlling acceleration and/or extraction of the charged particle beam; the rotation controller 147 controls any element associated with rotation of the patient 830 or gantry; and the timing to a period in respiration cycle controller 148 controls any aspects affecting delivery time of the charged particle beam to the patient. As a further example, the beam controller 185 optionally controls any magnetic and/or electric field about any magnet in the charged particle cancer therapy system 100. One or more beam state sensors 190 sense position, direction, intensity, and/or energy of the charged particles at one or more positions in the charged particle beam path. A tomography system 700, described infra, is optionally used to monitor intensity and/or position of the charged particle beam. Referring now to FIG. 1C, an illustrative exemplary embodiment of one version of the charged particle beam system 100 is provided. The number, position, and described type of components is illustrative and non-limiting in nature. In the illustrated embodiment, the injection system 120 or ion source or charged particle beam source generates protons. The injection system 120 optionally includes one or more of: a negative ion beam source, an ion beam focusing lens, and a tandem accelerator. The protons are delivered into a vacuum tube that runs into, through, and out of the synchrotron. The generated protons are delivered along an initial path 262. Optionally, focusing magnets 127, such as quadrupole magnets or injection quadrupole magnets, are used to focus the proton beam path. A quadrupole magnet is a focusing magnet. An injector bending magnet 128 bends the proton beam toward a plane of the synchrotron 130. The focused protons having an initial energy are introduced into an injector magnet 129, which is preferably an injection Lambertson magnet. Typically, the initial beam path 262 is along an axis off of, such as above, a circulating plane of the synchrotron 130. The injector bending magnet 128 and injector magnet 129 combine to move the protons into the synchrotron 130. Main bending magnets, dipole magnets, turning magnets, or circulating magnets 132 are used to turn the protons along a circulating beam path 264. A dipole magnet is a bending magnet. The main bending magnets 132 bend the initial beam path 262 into a circulating beam path 264. In this example, the main bending magnets 132 or circulating magnets are represented as four sets of four magnets to maintain the circulating beam path 264 into a stable circulating beam path. However, any number of magnets or sets of magnets are optionally used to move the protons around a single orbit in the circulation process. The protons pass through an accelerator 133. The accelerator accelerates the protons in the circulating beam path 264. As the protons are accelerated, the fields applied by the magnets are increased. Particularly, the speed of the protons achieved by the accelerator 133 are synchronized with magnetic fields of the main bending magnets 132 or circulating magnets to maintain stable circulation of the protons about a central point or region 136 of the synchrotron. At separate points in time the accelerator 133/main bending magnet 132 combination is used to accelerate and/or decelerate the circulating protons while maintaining the protons in the circulating path or orbit. An extraction element of an inflector/deflector system is used in combination with a Lambertson extraction magnet 137 to remove protons from their circulating beam path 264 within the synchrotron 130. One example of a deflector component is a Lambertson magnet. Typically the deflector moves the protons from the circulating plane to an axis off of the circulating plane, such as above the circulating plane. Extracted protons are preferably directed and/or focused using an extraction bending magnet 142 and optional extraction focusing magnets 141, such as quadrupole magnets, and optional bending magnets along a positively charged particle beam transport path 268 in a beam transport system 135, such as a beam path or proton beam path, into the scanning/targeting/delivery system 140. Two components of a scanning system 140 or targeting system typically include a first axis control 143, such as a vertical control, and a second axis control 144, such as a horizontal control. In one embodiment, the first axis control 143 allows for about 100 mm of vertical or y-axis scanning of the proton beam 268 and the second axis control 144 allows for about 700 mm of horizontal or x-axis scanning of the proton beam 268. A nozzle system 146 is used for directing the proton beam, for imaging the proton beam, for defining shape of the proton beam, and/or as a vacuum barrier between the low pressure beam path of the synchrotron and the atmosphere. Protons are delivered with control to the patient interface module 150 and to a tumor of a patient. All of the above listed elements are optional and may be used in various permutations and combinations. Ion Extraction from Ion Source A method and apparatus are described for extraction of ions from an ion source. For clarity of presentation and without loss of generality, examples focus on extraction of protons from the ion source. However, more generally cations of any charge are optionally extracted from a corresponding ion source with the techniques described herein. For instance, C4+ or C6+ are optionally extracted using the ion extraction methods and apparatus described herein. Further, by reversing polarity of the system, anions are optionally extracted from an anion source, where the anion is of any charge. Herein, for clarity of presentation and without loss of generality, ion extraction is coupled with tumor treatment and/or tumor imaging. However, the ion extraction is optional used in any method or apparatus using a stream or time discrete bunches of ions. Diode Extraction Referring now to FIG. 2A and FIG. 2B, a first ion extraction system is illustrated. The first ion extraction system uses a diode extraction system 200, where a first element of the diode extraction system is an ion source 122 or first electrode at a first potential and a second element 202 of the diode extraction system is at a second potential. Generally, the first potential is raised or lowered relative to the second potential to extract ions from the ion source 122 along the z-axis or the second potential is raised or lowered relative to the first potential to extract ions from the ion source 122 along the z-axis, where polarity of the potential difference determines if anions or cations are extracted from the ion source 122. Still referring to FIG. 2A and FIG. 2B, an example of ion extraction from the ion source 122 is described. As illustrated in FIG. 2A, in a non-extraction time period, a non-extraction diode potential, A1, of the ion source 122 is held at a potential equal to a potential, B1, of the second element 202. Referring now to FIG. 2B, during an extraction time period, a diode extraction potential, A2, of the ion source 122 is raised, causing a positively charged cation, such as the proton, to be drawn out of the ion chamber toward the lower potential of the second element 202. Similarly, if the diode extraction potential, A2, of the ion source is lowered relative a potential, B1, then an anion is extracted from the ion source 122 toward a higher potential of the second element 202. In the diode extraction system 200, the voltage of a large mass and corresponding large capacitance of the ion source 122 is raised or lowered, which takes time, has an RC time constant, and results in a range of temperatures of the plasma during the extraction time period, which is typically pulsed on and off with time. Particularly, as the potential of the ion source 122 is cycled with time, the ion source 122 temperature cycles, which results in a range of emittance values, resultant from conservation of momentum, and a corresponding less precise extraction beam. Alternatively, potential of the second element 202 is varied, altered, pulsed, or cycled, which reduces a range of emittance values during the extraction process. Triode Extraction Referring now to FIG. 2C and FIG. 2D, a second ion extraction system is illustrated. The second ion extraction system uses a triode extraction system 210. The triode extraction system 210 uses: (1) an ion source 122, (2) a gating electrode 204 also referred to as a suppression electrode, and (3) an extraction electrode 206. Optionally, a first electrode of the triode extraction system 210 is positioned proximate the ion source 122 and is maintained at a potential as described, infra, using the ion source as the first electrode of the triode extraction system. Generally, potential of the gating electrode 204 is raised and lowered to, as illustrated, stop and start extraction of a positive ion. Varying the potential of the gating electrode 204 has the advantages of altering the potential of a small mass with a correspondingly small capacitance and small RC time constant, which via conservation of momentum, reduces emittance of the extracted ions. Optionally, a first electrode maintained at the first potential of the ion source is used as the first element of the triode extraction system in place of the ion source 122 while also optionally further accelerating and/or focusing the extracted ions or set of ions using the extraction electrode 206. Several example further describe the triode extraction system 210. Still referring to FIG. 39, treating a blocked or shielded position of the tumor 720 is described. As illustrated, the patient 730 is laying along a z-axis into FIG. 39, where an arbitrary x/y plane is illustrated. If the patient were laying in the plane of FIG. 39, the first beamline 2811, the second beamline 2812, and/or the third beamline would optionally and preferably enter the treatment room 1222 along one or more axial or radial axes relative to a longitudinal axis of the patient 730 or within 75 degrees thereof and/or relative to a longitudinal axis of a spine of the patient, such as off of the x/y-plane by at least 15 degrees. As illustrated, the tumor 720 wraps around an obstructing object, such as a spine 721 of the patient. While treatment of the tumor 720 on a proximal side of the spine 721, such as at the second time, is achieved using a treatment beam 269 that has a Bragg peak, velocity, or energy that does not penetrate into the spine 721, preferably, the treatment beam 269 does not pass through the obstructing object that is the spine 721 as illustrated. To treat the distal side of the tumor, using the second beamline 2812 to define proximal and distal, the first beamline 2811 and/or the third beamline 2813 is used. As illustrated, the first beamline 2811, which has a nominal path not intersecting the tumor 720, is steered using a steering magnet, such as the electromagnetic and/or electrostatic steering of one or more final magnets in the beam transport system 135 described supra. Still referring to the first beamline 2811, the first mean unredirected beamline 2841 is steered to the proximal side of the tumor 720, such as as far as a first tangential path to a distal side, proximal side toward second beamline 2812, of the obstruction, the spine 721. Similarly, the second beamline 2812, which has a nominal path not intersecting the tumor 720 or the isocenter 263 is steered to intersect distal portions of the tumor 720, such as as far as a second tangential path to a proximal or distal side of the obstruction or spine 721. Generally, offsetting the tumor 720, along a first axis and/or preferably along 2 or three axes relative to the isocenter, toward a treatment nozzle, such as along the illustrated x- and/or y-axis from a traditional isocenter 263 toward the second beamline 2812, allows steering of a combination of beamline positions, such as the first beamline 2841 and the third beamline 2843, to treat the obstructed, blocked, and/or shielded distal side of the tumor 720 behind the obstruction. Still referring to FIG. 39, a low angle treatment system is illustrated. The inventor notes that the first undirected beamline 2841 and the third undirected beamline 2843, optionally and preferably form an angle of less than 180 degrees, such as less than 170, 160, or 150 degrees, and more preferably form an angle less than 90 degrees, such as less than 88, 86, 84, 82, 80, 75, or 70 degrees, while still being able to treat a blocked tumor position allowing a smaller and less costly beamline, gantry, and/or treatment room. The inventor further notes that one or more of the first, second, and third beamlines optionally have unsteered angles not intersecting the tumor 720 and/or not intersecting a traditional isocenter of a treatment room. Herein, the angle of the beamlines is based upon a projection into the viewed plane in the event that the beamlines do not intersect in three-dimensional space. Still referring to FIG. 39, a non-intersecting beamline system is illustrated. In various cases the first beamline 2841, the second beamline 2842, and/or the third beamline 2843 intersect at an isocenter point, intersect at a non-isocenter point, or cross in three dimensional space without intersecting. Similarly, two of the beamlines optionally intersect while the third beamline does not or two beamlines intersect at one point and the third beamline intersects with one of the first two beamlines at a second point. Generally, each of n beamlines or n beamline positions have their own paths where one or more axes, such as a calibrated axis for each beamline, and/or one or more fiducial markers are used to define a treatment space with or without a transform related to a traditional isocenter, where n is a positive integer greater than 1, 2, 3, 4, 5, or 10. Still referring to FIG. 39, in an optional configuration, the single repositionable treatment nozzle 2840 is illustrated connecting, at separate times, to the first beamline 2841, the second beamline 2842, and/or the third beamline 2843. Any of the beamlines optionally and preferably use a first set of focusing elements 2821, a second set of focusing elements 2822, a first set of turning magnets 2831, and/or a second set of turning magnets 2832, as described supra. Still referring to FIG. 39, the tumor 720 of the patient 730 is optionally treated using simultaneous treatment along two of more beamlines, such as the first beamline 2841, the second beamline 2842, and/or the third beamline 2843, where simultaneously comprises a time scales shorter than 0.001, 0.01, 0.1, 1, or 5 seconds. For the faster time scales, optionally and preferably, a second treatment nozzle for a second treatment line and or a third treatment nozzle for a third treatment line is optionally used. The positively charged particle beam transport path 268 from the beam transport system 135 is optionally rapidly redirected between paths and/or a beam splitter is used. Still yet another embodiment includes any combination and/or permutation of any of the elements described herein. The main controller, a localized communication apparatus, and/or a system for communication of information optionally comprises one or more subsystems stored on a client. The client is a computing platform configured to act as a client device or other computing device, such as a computer, personal computer, a digital media device, and/or a personal digital assistant. The client comprises a processor that is optionally coupled to one or more internal or external input device, such as a mouse, a keyboard, a display device, a voice recognition system, a motion recognition system, or the like. The processor is also communicatively coupled to an output device, such as a display screen or data link to display or send data and/or processed information, respectively. In one embodiment, the communication apparatus is the processor. In another embodiment, the communication apparatus is a set of instructions stored in memory that is carried out by the processor. The client includes a computer-readable storage medium, such as memory. The memory includes, but is not limited to, an electronic, optical, magnetic, or another storage or transmission data storage medium capable of coupling to a processor, such as a processor in communication with a touch-sensitive input device linked to computer-readable instructions. Other examples of suitable media include, for example, a flash drive, a CD-ROM, read only memory (ROM), random access memory (RAM), an application-specific integrated circuit (ASIC), a DVD, magnetic disk, an optical disk, and/or a memory chip. The processor executes a set of computer-executable program code instructions stored in the memory. The instructions may comprise code from any computer-programming language, including, for example, C originally of Bell Laboratories, C++, C#, Visual Basic® (Microsoft, Redmond, Wash.), Matlab® (MathWorks, Natick, Mass.), Java® (Oracle Corporation, Redwood City, Calif.), and JavaScript® (Oracle Corporation, Redwood City, Calif.). Herein, any number, such as 1, 2, 3, 4, 5, is optionally more than the number, less than the number, or within 1, 2, 5, 10, 20, or 50 percent of the number. Herein, an element and/or object is optionally manually and/or mechanically moved, such as along a guiding element, with a motor, and/or under control of the main controller. The particular implementations shown and described are illustrative of the invention and its best mode and are not intended to otherwise limit the scope of the present invention in any way. Indeed, for the sake of brevity, conventional manufacturing, connection, preparation, and other functional aspects of the system may not be described in detail. Furthermore, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and/or physical couplings between the various elements. Many alternative or additional functional relationships or physical connections may be present in a practical system. In the foregoing description, the invention has been described with reference to specific exemplary embodiments; however, it will be appreciated that various modifications and changes may be made without departing from the scope of the present invention as set forth herein. The description and figures are to be regarded in an illustrative manner, rather than a restrictive one and all such modifications are intended to be included within the scope of the present invention. Accordingly, the scope of the invention should be determined by the generic embodiments described herein and their legal equivalents rather than by merely the specific examples described above. For example, the steps recited in any method or process embodiment may be executed in any order and are not limited to the explicit order presented in the specific examples. Additionally, the components and/or elements recited in any apparatus embodiment may be assembled or otherwise operationally configured in a variety of permutations to produce substantially the same result as the present invention and are accordingly not limited to the specific configuration recited in the specific examples. Benefits, other advantages and solutions to problems have been described above with regard to particular embodiments; however, any benefit, advantage, solution to problems or any element that may cause any particular benefit, advantage or solution to occur or to become more pronounced are not to be construed as critical, required or essential features or components. As used herein, the terms “comprises”, “comprising”, or any variation thereof, are intended to reference a non-exclusive inclusion, such that a process, method, article, composition or apparatus that comprises a list of elements does not include only those elements recited, but may also include other elements not expressly listed or inherent to such process, method, article, composition or apparatus. Other combinations and/or modifications of the above-described structures, arrangements, applications, proportions, elements, materials or components used in the practice of the present invention, in addition to those not specifically recited, may be varied or otherwise particularly adapted to specific environments, manufacturing specifications, design parameters or other operating requirements without departing from the general principles of the same. Although the invention has been described herein with reference to certain preferred embodiments, one skilled in the art will readily appreciate that other applications may be substituted for those set forth herein without departing from the spirit and scope of the present invention. Accordingly, the invention should only be limited by the Claims included below. Still referring to FIG. 2C and FIG. 2D, optionally and preferably geometries of the gating electrode 204 and/or the extraction electrode 206 are used to focus the extracted ions along the initial ion beam path 262. Still referring to FIG. 2C and FIG. 2D, the lower emittance of the electron cyclotron resonance triode extraction system is optionally and preferably coupled with a downbeam or downstream radio-frequency quadrupole, used to focus the beam, and/or a synchrotron, used to accelerate the beam. Still referring to FIG. 2C and FIG. 2D, the lower emittance of the electron cyclotron resonance triode extraction system is maintained through the synchrotron 130 and to the tumor of the patient resulting in a more accurate, precise, smaller, and/or tighter treatment voxel of the charged particle beam or charged particle pulse striking the tumor. Still referring to FIG. 2C and FIG. 2D, the lower emittance of the electron cyclotron resonance triode extraction system reduces total beam spread through the synchrotron 130 and the tumor to one or more imaging elements, such as an optical imaging sheet or scintillation material emitting photons upon passage of the charged particle beam or striking of the charged particle beam, respectively. The lower emittance of the charged particle beam, optionally and preferably maintained through the accelerator system 134 and beam transport system yields a tighter, more accurate, more precise, and/or smaller particle beam or particle burst diameter at the imaging surfaces and/or imaging elements, which facilitates more accurate and precise tumor imaging, such as for subsequent tumor treatment or to adjust, while the patient waits in a treatment position, the charged particle treatment beam position. Any feature or features of any of the above provided examples are optionally and preferably combined with any feature described in other examples provided, supra, or herein. Ion Extraction from Accelerator Referring now to FIG. 3, both: (1) an exemplary proton beam extraction system 300 from the synchrotron 130 and (2) a charged particle beam intensity control system 305 are illustrated. For clarity, FIG. 3 removes elements represented in FIG. 1C, such as the turning magnets, which allows for greater clarity of presentation of the proton beam path as a function of time. Generally, protons are extracted from the synchrotron 130 by slowing the protons. As described, supra, the protons were initially accelerated in a circulating path, which is maintained with a plurality of main bending magnets 132. The circulating path is referred to herein as an original central beamline 264. The protons repeatedly cycle around a central point in the synchrotron 136. The proton path traverses through a radio frequency (RF) cavity system 310. To initiate extraction, an RF field is applied across a first blade 312 and a second blade 314, in the RF cavity system 310. The first blade 312 and second blade 314 are referred to herein as a first pair of blades. In the proton extraction process, an RF voltage is applied across the first pair of blades, where the first blade 312 of the first pair of blades is on one side of the circulating proton beam path 264 and the second blade 314 of the first pair of blades is on an opposite side of the circulating proton beam path 264. The applied RF field applies energy to the circulating charged-particle beam. The applied RF field alters the orbiting or circulating beam path slightly of the protons from the original central beamline 264 to an altered circulating beam path 265. Upon a second pass of the protons through the RF cavity system, the RF field further moves the protons off of the original proton beamline 264. For example, if the original beamline is considered as a circular path, then the altered beamline is slightly elliptical. The frequency of the applied RF field is timed to apply outward or inward movement to a given band of protons circulating in the synchrotron accelerator. Orbits of the protons are slightly more off axis compared to the original circulating beam path 264. Successive passes of the protons through the RF cavity system are forced further and further from the original central beamline 264 by altering the direction and/or intensity of the RF field with each successive pass of the proton beam through the RF field. Timing of application of the RF field and/or frequency of the RF field is related to the circulating charged particles circulation pathlength in the synchrotron 130 and the velocity of the charged particles so that the applied RF field has a period, with a peak-to-peak time period, equal to a period of time of beam circulation in the synchrotron 130 about the center 136 or an integer multiple of the time period of beam circulation about the center 136 of the synchrotron 130. Alternatively, the time period of beam circulation about the center 136 of the synchrotron 130 is an integer multiple of the RF period time. The RF period is optionally used to calculated the velocity of the charged particles, which relates directly to the energy of the circulating charged particles. The RF voltage is frequency modulated at a frequency about equal to the period of one proton cycling around the synchrotron for one revolution or at a frequency than is an integral multiplier of the period of one proton cycling about the synchrotron. The applied RF frequency modulated voltage excites a betatron oscillation. For example, the oscillation is a sine wave motion of the protons. The process of timing the RF field to a given proton beam within the RF cavity system is repeated thousands of times with each successive pass of the protons being moved approximately one micrometer further off of the original central beamline 264. For clarity, the approximately 1000 changing beam paths with each successive path of a given band of protons through the RF field are illustrated as the altered beam path 265. The RF time period is process is known, thus energy of the charged particles at time of hitting the extraction material or material 330, described infra, is known. With a sufficient sine wave betatron amplitude, the altered circulating beam path 265 touches and/or traverses a material 330, such as a foil or a sheet of foil. The foil is preferably a lightweight material, such as beryllium, a lithium hydride, a carbon sheet, or a material having low nuclear charge components. Herein, a material of low nuclear charge is a material composed of atoms consisting essentially of atoms having six or fewer protons. The foil is preferably about 10 to 150 microns thick, is more preferably about 30 to 100 microns thick, and is still more preferably about 40 to 60 microns thick. In one example, the foil is beryllium with a thickness of about 50 microns. When the protons traverse through the foil, energy of the protons is lost and the speed of the protons is reduced. Typically, a current is also generated, described infra. Protons moving at the slower speed travel in the synchrotron with a reduced radius of curvature 266 compared to either the original central beamline 264 or the altered circulating path 265. The reduced radius of curvature 266 path is also referred to herein as a path having a smaller diameter of trajectory or a path having protons with reduced energy. The reduced radius of curvature 266 is typically about two millimeters less than a radius of curvature of the last pass of the protons along the altered proton beam path 265. The thickness of the material 330 is optionally adjusted to create a change in the radius of curvature, such as about ½, 1, 2, 3, or 4 mm less than the last pass of the protons 265 or original radius of curvature 264. The reduction in velocity of the charged particles transmitting through the material 330 is calculable, such as by using the pathlength of the betatron oscillating charged particle beam through the material 330 and/or using the density of the material 330. Protons moving with the smaller radius of curvature travel between a second pair of blades. In one case, the second pair of blades is physically distinct and/or is separated from the first pair of blades. In a second case, one of the first pair of blades is also a member of the second pair of blades. For example, the second pair of blades is the second blade 314 and a third blade 316 in the RF cavity system 310. A high voltage DC signal, such as about 1 to 5 kV, is then applied across the second pair of blades, which directs the protons out of the synchrotron through an extraction magnet 137, such as a Lambertson extraction magnet, into a transport path 268. Control of acceleration of the charged particle beam path in the synchrotron with the accelerator and/or applied fields of the turning magnets in combination with the above described extraction system allows for control of the intensity of the extracted proton beam, where intensity is a proton flux per unit time or the number of protons extracted as a function of time. For example, when a current is measured beyond a threshold, the RF field modulation in the RF cavity system is terminated or reinitiated to establish a subsequent cycle of proton beam extraction. This process is repeated to yield many cycles of proton beam extraction from the synchrotron accelerator. In another embodiment, instead of moving the charged particles to the material 330, the material 330 is mechanically moved to the circulating charged particles. Particularly, the material 330 is mechanically or electromechanically translated into the path of the circulating charged particles to induce the extraction process, described supra. In this case, the velocity or energy of the circulating charged particle beam is calculable using the pathlength of the beam path about the center 136 of the synchrotron 130 and from the force applied by the bending magnets 132. In either case, because the extraction system does not depend on any change in magnetic field properties, it allows the synchrotron to continue to operate in acceleration or deceleration mode during the extraction process. Stated differently, the extraction process does not interfere with synchrotron acceleration. In stark contrast, traditional extraction systems introduce a new magnetic field, such as via a hexapole, during the extraction process. More particularly, traditional synchrotrons have a magnet, such as a hexapole magnet, that is off during an acceleration stage. During the extraction phase, the hexapole magnetic field is introduced to the circulating path of the synchrotron. The introduction of the magnetic field necessitates two distinct modes, an acceleration mode and an extraction mode, which are mutually exclusive in time. The herein described system allows for acceleration and/or deceleration of the proton during the extraction step and tumor treatment without the use of a newly introduced magnetic field, such as by a hexapole magnet. Charged Particle Beam Intensity Control Control of applied field, such as a radio-frequency (RF) field, frequency and magnitude in the RF cavity system 310 allows for intensity control of the extracted proton beam, where intensity is extracted proton flux per unit time or the number of protons extracted as a function of time. Still referring FIG. 3, the intensity control system 305 is further described. In this example, an intensity control feedback loop is added to the extraction system, described supra. When protons in the proton beam hit the material 330 electrons are given off from the material 330 resulting in a current. The resulting current is converted to a voltage and is used as part of an ion beam intensity monitoring system or as part of an ion beam feedback loop for controlling beam intensity. The voltage is optionally measured and sent to the main controller 110 or to an intensity controller subsystem 340, which is preferably in communication or under the direction of the main controller 110. More particularly, when protons in the charged particle beam path pass through the material 330, some of the protons lose a small fraction of their energy, such as about one-tenth of a percent, which results in a secondary electron. That is, protons in the charged particle beam push some electrons when passing through material 330 giving the electrons enough energy to cause secondary emission. The resulting electron flow results in a current or signal that is proportional to the number of protons going through the target or extraction material 330. The resulting current is preferably converted to voltage and amplified. The resulting signal is referred to as a measured intensity signal. The amplified signal or measured intensity signal resulting from the protons passing through the material 330 is optionally used in monitoring the intensity of the extracted protons and is preferably used in controlling the intensity of the extracted protons. For example, the measured intensity signal is compared to a goal signal, which is predetermined in an irradiation of the tumor plan. The difference between the measured intensity signal and the planned for goal signal is calculated. The difference is used as a control to the RF generator. Hence, the measured flow of current resulting from the protons passing through the material 330 is used as a control in the RF generator to increase or decrease the number of protons undergoing betatron oscillation and striking the material 330. Hence, the voltage determined off of the material 330 is used as a measure of the orbital path and is used as a feedback control to control the RF cavity system. In one example, the intensity controller subsystem 340 preferably additionally receives input from: (1) a detector 350, which provides a reading of the actual intensity of the proton beam and/or (2) an irradiation plan 360. The irradiation plan provides the desired intensity of the proton beam for each x, y, energy, and/or rotational position of the patient/tumor as a function of time. Thus, the intensity controller 340 receives the desired intensity from the irradiation plan 350, the actual intensity from the detector 350 and/or a measure of intensity from the material 330, and adjusts the amplitude and/or the duration of application of the applied radio-frequency field in the RF cavity system 310 to yield an intensity of the proton beam that matches the desired intensity from the irradiation plan 360. As described, supra, the protons striking the material 330 is a step in the extraction of the protons from the synchrotron 130. Hence, the measured intensity signal is used to change the number of protons per unit time being extracted, which is referred to as intensity of the proton beam. The intensity of the proton beam is thus under algorithm control. Further, the intensity of the proton beam is controlled separately from the velocity of the protons in the synchrotron 130. Hence, intensity of the protons extracted and the energy of the protons extracted are independently variable. Still further, the intensity of the extracted protons is controllably variable while scanning the charged particles beam in the tumor from one voxel to an adjacent voxel as a separate hexapole and separated time period from acceleration and/or treatment is not required, as described supra. For example, protons initially move at an equilibrium trajectory in the synchrotron 130. An RF field is used to excite or move the protons into a betatron oscillation. In one case, the frequency of the protons orbit is about 10 MHz. In one example, in about one millisecond or after about 10,000 orbits, the first protons hit an outer edge of the target material 130. The specific frequency is dependent upon the period of the orbit. Upon hitting the material 130, the protons push electrons through the foil to produce a current. The current is converted to voltage and amplified to yield a measured intensity signal. The measured intensity signal is used as a feedback input to control the applied RF magnitude or RF field. An energy beam sensor, described infra, is optionally used as a feedback control to the RF field frequency or RF field of the RF field extraction system 310 to dynamically control, modify, and/or alter the delivered charge particle beam energy, such as in a continuous pencil beam scanning system operating to treat tumor voxels without alternating between an extraction phase and a treatment phase. Preferably, the measured intensity signal is compared to a target signal and a measure of the difference between the measured intensity signal and target signal is used to adjust the applied RF field in the RF cavity system 310 in the extraction system to control the intensity of the protons in the extraction step. Stated again, the signal resulting from the protons striking and/or passing through the material 130 is used as an input in RF field modulation. An increase in the magnitude of the RF modulation results in protons hitting the foil or material 130 sooner. By increasing the RF, more protons are pushed into the foil, which results in an increased intensity, or more protons per unit time, of protons extracted from the synchrotron 130. In another example, a detector 350 external to the synchrotron 130 is used to determine the flux of protons extracted from the synchrotron and a signal from the external detector is used to alter the RF field, RF intensity, RF amplitude, and/or RF modulation in the RF cavity system 310. Here the external detector generates an external signal, which is used in a manner similar to the measured intensity signal, described in the preceding paragraphs. Preferably, an algorithm or irradiation plan 360 is used as an input to the intensity controller 340, which controls the RF field modulation by directing the RF signal in the betatron oscillation generation in the RF cavity system 310. The irradiation plan 360 preferably includes the desired intensity of the charged particle beam as a function of time and/or energy of the charged particle beam as a function of time, for each patient rotation position, and/or for each x-, y-position of the charged particle beam. In yet another example, when a current from material 330 resulting from protons passing through or hitting material is measured beyond a threshold, the RF field modulation in the RF cavity system is terminated or reinitiated to establish a subsequent cycle of proton beam extraction. This process is repeated to yield many cycles of proton beam extraction from the synchrotron accelerator. In still yet another embodiment, intensity modulation of the extracted proton beam is controlled by the main controller 110. The main controller 110 optionally and/or additionally controls timing of extraction of the charged particle beam and energy of the extracted proton beam. The benefits of the system include a multi-dimensional scanning system. Particularly, the system allows independence in: (1) energy of the protons extracted and (2) intensity of the protons extracted. That is, energy of the protons extracted is controlled by an energy control system and an intensity control system controls the intensity of the extracted protons. The energy control system and intensity control system are optionally independently controlled. Preferably, the main controller 110 controls the energy control system and the main controller 110 simultaneously controls the intensity control system to yield an extracted proton beam with controlled energy and controlled intensity where the controlled energy and controlled intensity are independently variable and/or continually available as a separate extraction phase and acceleration phase are not required, as described supra. Thus the irradiation spot hitting the tumor is under independent control of: time; energy; intensity; x-axis position, where the x-axis represents horizontal movement of the proton beam relative to the patient, and y-axis position, where the y-axis represents vertical movement of the proton beam relative to the patient. In addition, the patient is optionally independently translated and/or rotated relative to a translational axis of the proton beam at the same time. Beam Transport The beam transport system 135 is used to move the charged particles from the accelerator to the patient, such as via a nozzle in a gantry, described infra. Charged Particle Energy The beam transport system 135 optionally includes means for determining an energy of the charged particles in the charged particle beam. For example, an energy of the charged particle beam is determined via calculation, such as via equation 1, using knowledge of a magnet geometry and applied magnetic field to determine mass and/or energy. Referring now to equation 1, for a known magnet geometry, charge, q, and magnetic field, B, the Larmor radius, ρL, or magnet bend radius is defined as: ρ L = v ⊥ Ω c = 2 Em qB ( eq . 1 ) where: v⊥ is the ion velocity perpendicular to the magnetic field, Ωc is the cyclotron frequency, q is the charge of the ion, B is the magnetic field, m is the mass of the charge particle, and E is the charged particle energy. Solving for the charged particle energy yields equation 2. E = ( ρ L qB ) 2 2 m ( eq . 2 ) Thus, an energy of the charged particle in the charged particle beam in the beam transport system 135 is calculable from the know magnet geometry, known or measured magnetic field, charged particle mass, charged particle charge, and the known magnet bend radius, which is proportional to and/or equivalent to the Larmor radius. Nozzle After extraction from the synchrotron 130 and transport of the charged particle beam along the proton beam path 268 in the beam transport system 135, the charged particle beam exits through the nozzle system 146. In one example, the nozzle system includes a nozzle foil covering an end of the nozzle system 146 or a cross-sectional area within the nozzle system forming a vacuum seal. The nozzle system includes a nozzle that expands in x/y-cross-sectional area along the z-axis of the proton beam path 268 to allow the proton beam 268 to be scanned along the x-axis and y-axis by the vertical control element and horizontal control element, respectively. The nozzle foil is preferably mechanically supported by the outer edges of an exit port of the nozzle or nozzle system 146. An example of a nozzle foil is a sheet of about 0.1 inch thick aluminum foil. Generally, the nozzle foil separates atmosphere pressures on the patient side of the nozzle foil from the low pressure region, such as about 10−5 to 10−7 torr region, on the synchrotron 130 side of the nozzle foil. The low pressure region is maintained to reduce scattering of the circulating charged particle beam in the synchrotron. Herein, the exit foil of the nozzle is optionally the first sheet 760 of the charged particle beam state determination system 750, described infra. Charged Particle Control Referring now to FIG. 4A, FIG. 4B, FIG. 5, FIG. 6A, and FIG. 6B, a charged particle beam control system is described where one or more patient specific beam control assemblies are removably inserted into the charged particle beam path proximate the nozzle of the charged particle cancer therapy system 100, where the patient specific beam control assemblies adjust the beam energy, diameter, cross-sectional shape, focal point, and/or beam state of the charged particle beam to properly couple energy of the charged particle beam to the individual's specific tumor. Beam Control Tray Referring now to FIG. 4A and FIG. 4B, a beam control tray assembly 400 is illustrated in a top view and side view, respectively. The beam control tray assembly 400 optionally comprises any of a tray frame 410, a tray aperture 412, a tray handle 420, a tray connector/communicator 430, and means for holding a patient specific tray insert 510, described infra. Generally, the beam control tray assembly 400 is used to: (1) hold the patient specific tray insert 510 in a rigid location relative to the beam control tray 400, (2) electronically identify the held patient specific tray insert 510 to the main controller 110, and (3) removably insert the patient specific tray insert 510 into an accurate and precise fixed location relative to the charged particle beam, such as the proton beam path 268 at the nozzle of the charged particle cancer therapy system 100. For clarity of presentation and without loss of generality, the means for holding the patient specific tray insert 510 in the tray frame 410 of the beam control tray assembly 400 is illustrated as a set of recessed set screws 415. However, the means for holding the patient specific tray insert 510 relative to the rest of the beam control tray assembly 400 is optionally any mechanical and/or electromechanical positioning element, such as a latch, clamp, fastener, clip, slide, strap, or the like. Generally, the means for holding the patient specific tray insert 510 in the beam control tray 400 fixes the tray insert and tray frame relative to one another even when rotated along and/or around multiple axes, such as when attached to a charged particle cancer therapy system 100, nozzle system 146, dynamic gantry nozzle, or gantry nozzle, which is an optional element of the nozzle system 146, that moves in three-dimensional space relative to a fixed point in the beamline, proton beam path 268, and/or a given patient position. As illustrated in FIG. 4A and FIG. 4B, the recessed set screws 415 fix the patient specific tray insert 510 into the aperture 412 of the tray frame 410. The tray frame 410 is illustrated as circumferentially surrounding the patient specific tray insert 510, which aids in structural stability of the beam control tray assembly 400. However, generally the tray frame 410 is of any geometry that forms a stable beam control tray assembly 400. Still referring to FIG. 4A and now referring to FIG. 5 and FIG. 6A, the optional tray handle 420 is used to manually insert/retract the beam control tray assembly 400 into a receiving element of the gantry nozzle, nozzle system 146, or dynamic gantry nozzle. While the beam control tray assembly 400 is optionally inserted into the charged particle beam path 268 at any point after extraction from the synchrotron 130, the beam control tray assembly 400 is preferably inserted into the positively charged particle beam proximate the nozzle system 146 or dynamic gantry nozzle as control of the beam shape is preferably done with little space for the beam shape to defocus before striking the tumor. Optionally, insertion and/or retraction of the beam control tray assembly 400 is semi-automated, such as in a manner of a digital-video disk player receiving a digital-video disk, with a selected auto load and/or a selected auto unload feature. Patient Specific Tray Insert Referring again to FIG. 5, a system of assembling trays 500 is described. The beam control tray assembly 400 optionally and preferably has interchangeable patient specific tray inserts 510, such as a range shifter insert 511, a patient specific ridge filter insert 512, an aperture insert 513, a compensator insert 514, or a blank insert 515. As described, supra, any of the range shifter insert 511, the patient specific ridge filter insert 512, the aperture insert 513, the compensator insert 514, or the blank insert 515 after insertion into the tray frame 410 are inserted as the beam control tray assembly 400 into the positively charged particle beam path 268, such as proximate the nozzle system 146 or dynamic gantry nozzle. Still referring to FIG. 5, the patient specific tray inserts 510 are further described. The patient specific tray inserts comprise a combination of any of: (1) a standardized beam control insert and (2) a patient specific beam control insert. For example, the range shifter insert or 511 or compensator insert 514 used to control the depth of penetration of the charged particle beam into the patient is optionally: (a) a standard thickness of a beam slowing material, such as a first thickness of Lucite, an acrylic, a clear plastic, and/or a thermoplastic material, (b) one member of a set of members of varying thicknesses and/or densities where each member of the set of members slows the charged particles in the beam path by a known amount, or (c) is a material with a density and thickness designed to slow the charged particles by a customized amount for the individual patient being treated, based on the depth of the individual's tumor in the tissue, the thickness of intervening tissue, and/or the density of intervening bone/tissue. Similarly, the ridge filter insert 512 used to change the focal point or shape of the beam as a function of depth is optionally: (1) selected from a set of ridge filters where different members of the set of ridge filters yield different focal depths or (2) customized for treatment of the individual's tumor based on position of the tumor in the tissue of the individual. Similarly, the aperture insert is: (1) optionally selected from a set of aperture shapes or (2) is a customized individual aperture insert 513 designed for the specific shape of the individual's tumor. The blank insert 515 is an open slot, but serves the purpose of identifying slot occupancy, as described infra. Slot Occupancy/Identification Referring again to FIG. 4A, FIG. 4B, and FIG. 5, occupancy and identification of the particular patient specific tray insert 510 into the beam control tray assembly 400 is described. Generally, the beam control tray assembly 400 optionally contains means for identifying, to the main controller 110 and/or a treatment delivery control system described infra, the specific patient tray insert 510 and its location in the charged particle beam path 268. First, the particular tray insert is optionally labeled and/or communicated to the beam control tray assembly 400 or directly to the main controller 110. Second, the beam control tray assembly 400 optionally communicates the tray type and/or tray insert to the main controller 110. In various embodiments, communication of the particular tray insert to the main controller 110 is performed: (1) directly from the tray insert, (2) from the tray insert 510 to the tray assembly 400 and subsequently to the main controller 110, and/or (3) directly from the tray assembly 400. Generally, communication is performed wirelessly and/or via an established electromechanical link. Identification is optionally performed using a radio-frequency identification label, use of a barcode, or the like, and/or via operator input. Examples are provided to further clarify identification of the patient specific tray insert 510 in a given beam control tray assembly 400 to the main controller. In a first example, one or more of the patient specific tray inserts 510, such as the range shifter insert 511, the patient specific ridge filter insert 512, the aperture insert 513, the compensator insert 514, or the blank insert 515 include an identifier 520 and/or and a first electromechanical identifier plug 530. The identifier 520 is optionally a label, a radio-frequency identification tag, a barcode, a 2-dimensional bar-code, a matrix-code, or the like. The first electromechanical identifier plug 530 optionally includes memory programmed with the particular patient specific tray insert information and a connector used to communicate the information to the beam control tray assembly 400 and/or to the main controller 110. As illustrated in FIG. 5, the first electromechanical identifier plug 530 affixed to the patient specific tray insert 510 plugs into a second electromechanical identifier plug, such as the tray connector/communicator 430, of the beam control tray assembly 400, which is described infra. In a second example, the beam control tray assembly 400 uses the second electromechanical identifier plug to send occupancy, position, and/or identification information related to the type of tray insert or the patient specific tray insert 510 associated with the beam control tray assembly to the main controller 110. For example, a first tray assembly is configured with a first tray insert and a second tray assembly is configured with a second tray insert. The first tray assembly sends information to the main controller 110 that the first tray assembly holds the first tray insert, such as a range shifter, and the second tray assembly sends information to the main controller 110 that the second tray assembly holds the second tray insert, such as an aperture. The second electromechanical identifier plug optionally contains programmable memory for the operator to input the specific tray insert type, a selection switch for the operator to select the tray insert type, and/or an electromechanical connection to the main controller. The second electromechanical identifier plug associated with the beam control tray assembly 400 is optionally used without use of the first electromechanical identifier plug 530 associated with the tray insert 510. In a third example, one type of tray connector/communicator 430 is used for each type of patient specific tray insert 510. For example, a first connector/communicator type is used for holding a range shifter insert 511, while a second, third, fourth, and fifth connector/communicator type is used for trays respectively holding a patient specific ridge filter insert 512, an aperture insert 513, a compensator insert 514, or a blank insert 515. In one case, the tray communicates tray type with the main controller. In a second case, the tray communicates patient specific tray insert information with the main controller, such as an aperture identifier custom built for the individual patient being treated. Tray Insertion/Coupling Referring now to FIG. 6A and FIG. 6B a beam control insertion process 600 is described. The beam control insertion process 600 comprises: (1) insertion of the beam control tray assembly 400 and the associated patient specific tray insert 510 into the charged particle beam path 268 and/or dynamic gantry nozzle 610, such as into a tray assembly receiver 620 and (2) an optional partial or total retraction of beam of the tray assembly receiver 620 into the dynamic gantry nozzle 610. Referring now to FIG. 6A, insertion of one or more of the beam control tray assemblies 400 and the associated patient specific tray inserts 510 into the dynamic gantry nozzle 610 is further described. In FIG. 6A, three beam control tray assemblies, of a possible n tray assemblies, are illustrated, a first tray assembly 402, a second tray assembly 404, and a third tray assembly 406, where n is a positive integer of 1, 2, 3, 4, 5 or more. As illustrated, the first tray assembly 402 slides into a first receiving slot 403, the second tray assembly 404 slides into a second receiving slot 405, and the third tray assembly 406 slides into a third receiving slot 407. Generally, any tray optionally inserts into any slot or tray types are limited to particular slots through use of a mechanical, physical, positional, and/or steric constraints, such as a first tray type configured for a first insert type having a first size and a second tray type configured for a second insert type having a second distinct size at least ten percent different from the first size. Still referring to FIG. 6A, identification of individual tray inserts inserted into individual receiving slots is further described. As illustrated, sliding the first tray assembly 402 into the first receiving slot 403 connects the associated electromechanical connector/communicator 430 of the first tray assembly 402 to a first receptor 626. The electromechanical connector/communicator 430 of the first tray assembly communicates tray insert information of the first beam control tray assembly to the main controller 110 via the first receptor 626. Similarly, sliding the second tray assembly 404 into the second receiving slot 405 connects the associated electromechanical connector/communicator 430 of the second tray assembly 404 into a second receptor 627, which links communication of the associated electromechanical connector/communicator 430 with the main controller 110 via the second receptor 627, while a third receptor 628 connects to the electromechanical connected placed into the third slot 407. The non-wireless/direct connection is preferred due to the high radiation levels within the treatment room and the high shielding of the treatment room, which both hinder wireless communication. The connection of the communicator and the receptor is optionally of any configuration and/or orientation. Tray Receiver Assembly Retraction Referring again to FIG. 6A and FIG. 6B, retraction of the tray receiver assembly 620 relative to a nozzle end 612 of the dynamic gantry nozzle 610 is described. The tray receiver assembly 620 comprises a framework to hold one or more of the beam control tray assemblies 400 in one or more slots, such as through use of a first tray receiver assembly side 622 through which the beam control tray assemblies 400 are inserted and/or through use of a second tray receiver assembly side 624 used as a backstop, as illustrated holding the plugin receptors configured to receive associated tray connector/communicators 430, such as the first, second, and third receptors 626, 627, 628. Optionally, the tray receiver assembly 620 retracts partially or completely into the dynamic gantry nozzle 610 using a retraction mechanism 660 configured to alternately retract and extend the tray receiver assembly 620 relative to a nozzle end 612 of the gantry nozzle 610, such as along a first retraction track 662 and a second retraction track 664 using one or more motors and computer control. Optionally the tray receiver assembly 620 is partially or fully retracted when moving the gantry, nozzle, and/or gantry nozzle 610 to avoid physical constraints of movement, such as potential collision with another object in the patient treatment room. For clarity of presentation and without loss of generality, several examples of loading patient specific tray inserts into tray assemblies with subsequent insertion into an positively charged particle beam path proximate a gantry nozzle 610 are provided. In a first example, a single beam control tray assembly 400 is used to control the charged particle beam 268 in the charged particle cancer therapy system 100. In this example, a patient specific range shifter insert 511, which is custom fabricated for a patient, is loaded into a patient specific tray insert 510 to form a first tray assembly 402, where the first tray assembly 402 is loaded into the third receptor 628, which is fully retracted into the gantry nozzle 610. In a second example, two beam control assemblies 400 are used to control the charged particle beam 268 in the charged particle cancer therapy system 100. In this example, a patient specific ridge filter 512 is loaded into a first tray assembly 402, which is loaded into the second receptor 627 and a patient specific aperture 513 is loaded into a second tray assembly 404, which is loaded into the first receptor 626 and the two associated tray connector/communicators 430 using the first receptor 626 and second receptor 627 communicate to the main controller 110 the patient specific tray inserts 510. The tray receiver assembly 620 is subsequently retracted one slot so that the patient specific ridge filter 512 and the patient specific aperture reside outside of and at the nozzle end 612 of the gantry nozzle 610. In a third example, three beam control tray assemblies 400 are used, such as a range shifter 511 in a first tray inserted into the first receiving slot 403, a compensator in a second tray inserted into the second receiving slot 405, and an aperture in a third tray inserted into the third receiving slot 407. Generally, any patient specific tray insert 510 is inserted into a tray frame 410 to form a beam control tray assembly 400 inserted into any slot of the tray receiver assembly 620 and the tray assembly is not retracted or retracted any distance into the gantry nozzle 610. Tomography/Beam State In one embodiment, the charged particle tomography apparatus is used to image a tumor in a patient. As current beam position determination/verification is used in both tomography and cancer therapy treatment, for clarity of presentation and without limitation beam state determination is also addressed in this section. However, beam state determination is optionally used separately and without tomography. In another example, the charged particle tomography apparatus is used in combination with a charged particle cancer therapy system using common elements. For example, tomographic imaging of a cancerous tumor is performed using charged particles generated with an injector, accelerator, and guided with a delivery system that are part of the cancer therapy system, described supra. In various examples, the tomography imaging system is optionally simultaneously operational with a charged particle cancer therapy system using common elements, allows tomographic imaging with rotation of the patient, is operational on a patient in an upright, semi-upright, and/or horizontal position, is simultaneously operational with X-ray imaging, and/or allows use of adaptive charged particle cancer therapy. Further, the common tomography and cancer therapy apparatus elements are optionally operational in a multi-axis and/or multi-field raster beam mode. In conventional medical X-ray tomography, a sectional image through a body is made by moving one or both of an X-ray source and the X-ray film in opposite directions during the exposure. By modifying the direction and extent of the movement, operators can select different focal planes, which contain the structures of interest. More modern variations of tomography involve gathering projection data from multiple directions by moving the X-ray source and feeding the data into a tomographic reconstruction software algorithm processed by a computer. Herein, in stark contrast to known methods, the radiation source is a charged particle, such as a proton ion beam or a carbon ion beam. A proton beam is used herein to describe the tomography system, but the description applies to a heavier ion beam, such as a carbon ion beam. Further, in stark contrast to known techniques, herein the radiation source is preferably stationary while the patient is rotated. Referring now to FIG. 7, an example of a tomography apparatus is described and an example of a beam state determination is described. In this example, the tomography system 700 uses elements in common with the charged particle beam system 100, including elements of one or more of the injection system 120, the accelerator 130, a positively charged particle beam transport path 268 within a beam transport housing 320 in the beam transport system 135, the targeting/delivery system 140, the patient interface module 150, the display system 160, and/or the imaging system 170, such as the X-ray imaging system. The scintillation material is optionally one or more scintillation plates, such as a scintillating plastic, used to measure energy, intensity, and/or position of the charged particle beam. For instance, a scintillation material 710 or scintillation plate is positioned behind the patient 730 relative to the targeting/delivery system 140 elements, which is optionally used to measure intensity and/or position of the charged particle beam after transmitting through the patient. Optionally, a second scintillation plate or a charged particle induced photon emitting sheet, described infra, is positioned prior to the patient 730 relative to the targeting/delivery system 140 elements, which is optionally used to measure incident intensity and/or position of the charged particle beam prior to transmitting through the patient. The charged particle beam system 100 as described has proven operation at up to and including 330 MeV, which is sufficient to send protons through the body and into contact with the scintillation material. Particularly, 250 MeV to 330 MeV are used to pass the beam through a standard sized patient with a standard sized pathlength, such as through the chest. The intensity or count of protons hitting the plate as a function of position is used to create an image. The velocity or energy of the proton hitting the scintillation plate is also used in creation of an image of the tumor 720 and/or an image of the patient 730. The patient 730 is rotated about the y-axis and a new image is collected. Preferably, a new image is collected with about every one degree of rotation of the patient resulting in about 360 images that are combined into a tomogram using tomographic reconstruction software. The tomographic reconstruction software uses overlapping rotationally varied images in the reconstruction. Optionally, a new image is collected at about every 2, 3, 4, 5, 10, 15, 30, or 45 degrees of rotation of the patient. Herein, the scintillation material 710 or scintillator is any material that emits a photon when struck by a positively charged particle or when a positively charged particle transfers energy to the scintillation material sufficient to cause emission of light. Optionally, the scintillation material emits the photon after a delay, such as in fluorescence or phosphorescence. However, preferably, the scintillator has a fast fifty percent quench time, such as less than 0.0001, 0.001, 0.01, 0.1, 1, 10, 100, or 1,000 milliseconds, so that the light emission goes dark, falls off, or terminates quickly. Preferred scintillation materials include sodium iodide, potassium iodide, cesium iodide, an iodide salt, and/or a doped iodide salt. Additional examples of the scintillation materials include, but are not limited to: an organic crystal, a plastic, a glass, an organic liquid, a luminophor, and/or an inorganic material or inorganic crystal, such as barium fluoride, BaF2; calcium fluoride, CaF2, doped calcium fluoride, sodium iodide, NaI; doped sodium iodide, sodium iodide doped with thallium, NaI(TI); cadmium tungstate, CdWO4; bismuth germanate; cadmium tungstate, CdWO4; calcium tungstate, CaWO4; cesium iodide, CsI; doped cesium iodide; cesium iodide doped with thallium, CsI(Tl); cesium iodide doped with sodium CsI(Na); potassium iodide, KI; doped potassium iodide, gadolinium oxysulfide, Gd2O2S; lanthanum bromide doped with cerium, LaBr3(Ce); lanthanum chloride, LaCl3; cesium doped lanthanum chloride, LaCl3(Ce); lead tungstate, PbWO4; LSO or lutetium oxyorthosilicate (Lu2SiO5); LYSO, Lu1.8Y0.2SiO5(Ce); yttrium aluminum garnet, YAG(Ce); zinc sulfide, ZnS(Ag); and zinc tungstate, ZnWO4. In one embodiment, a tomogram or an individual tomogram section image is collected at about the same time as cancer therapy occurs using the charged particle beam system 100. For example, a tomogram is collected and cancer therapy is subsequently performed: without the patient moving from the positioning systems, such as in a semi-vertical partial immobilization system, a sitting partial immobilization system, or the a laying position. In a second example, an individual tomogram slice is collected using a first cycle of the accelerator 130 and using a following cycle of the accelerator 130, the tumor 720 is irradiated, such as within about 1, 2, 5, 10, 15 or 30 seconds. In a third case, about 2, 3, 4, or 5 tomogram slices are collected using 1, 2, 3, 4, or more rotation positions of the patient 730 within about 5, 10, 15, 30, or 60 seconds of subsequent tumor irradiation therapy. In another embodiment, the independent control of the tomographic imaging process and X-ray collection process allows simultaneous single and/or multi-field collection of X-ray images and tomographic images easing interpretation of multiple images. Indeed, the X-ray and tomographic images are optionally overlaid to from a hybrid X-ray/proton beam tomographic image as the patient 730 is optionally in the same position for each image. In still another embodiment, the tomogram is collected with the patient 730 in the about the same position as when the patient's tumor is treated using subsequent irradiation therapy. For some tumors, the patient being positioned in the same upright or semi-upright position allows the tumor 720 to be separated from surrounding organs or tissue of the patient 730 better than in a laying position. Positioning of the scintillation material 710 behind the patient 730 allows the tomographic imaging to occur while the patient is in the same upright or semi-upright position. The use of common elements in the tomographic imaging and in the charged particle cancer therapy allows benefits of the cancer therapy, described supra, to optionally be used with the tomographic imaging, such as proton beam x-axis control, proton beam y-axis control, control of proton beam energy, control of proton beam intensity, timing control of beam delivery to the patient, rotation control of the patient, and control of patient translation all in a raster beam mode of proton energy delivery. The use of a single proton or cation beamline for both imaging and treatment facilitates eases patient setup, reduces alignment uncertainties, reduces beam sate uncertainties, and eases quality assurance. In yet still another embodiment, initially a three-dimensional tomographic proton based reference image is collected, such as with hundreds of individual rotation images of the tumor 720 and patient 730. Subsequently, just prior to proton treatment of the cancer, just a few 2-dimensional control tomographic images of the patient are collected, such as with a stationary patient or at just a few rotation positions, such as an image straight on to the patient, with the patient rotated about 45 degrees each way, and/or the patient rotated about 90 degrees each way about the y-axis. The individual control images are compared with the 3-dimensional reference image. An adaptive proton therapy is subsequently performed where: (1) the proton cancer therapy is not used for a given position based on the differences between the 3-dimensional reference image and one or more of the 2-dimensional control images and/or (2) the proton cancer therapy is modified in real time based on the differences between the 3-dimensional reference image and one or more of the 2-dimensional control images. Charged Particle State Determination/Verification/Photonic Monitoring Still referring to FIG. 7, the tomography system 700 is optionally used with a charged particle beam state determination system 750, optionally used as a charged particle verification system. The charged particle state determination system 750 optionally measures, determines, and/or verifies one of more of: (1) position of the charged particle beam, such as the treatment beam 269, (2) direction of the treatment beam 269, (3) intensity of the treatment beam 269, (4) energy of the treatment beam 269, (5) position, direction, intensity, and/or energy of the charged particle beam, such as a residual charged particle beam 267 after passing through a sample or the patient 730, and (6) a history of the charged particle beam. For clarity of presentation and without loss of generality, a description of the charged particle beam state determination system 750 is described and illustrated separately in FIG. 8 and FIG. 9A; however, as described herein elements of the charged particle beam state determination system 750 are optionally and preferably integrated into the nozzle system 146 and/or the tomography system 700 of the charged particle treatment system 100. More particularly, any element of the charged particle beam state determination system 750 is integrated into the nozzle system 146, the dynamic gantry nozzle 610, and/or tomography system 700, such as a surface of the scintillation material 710 or a surface of a scintillation detector, plate, or system. The nozzle system 146 or the dynamic gantry nozzle 610 provides an outlet of the charged particle beam from the vacuum tube initiating at the injection system 120 and passing through the synchrotron 130 and beam transport system 135. Any plate, sheet, fluorophore, or detector of the charged particle beam state determination system is optionally integrated into the nozzle system 146. For example, an exit foil of the nozzle 610 is optionally a first sheet 760 of the charged particle beam state determination system 750 and a first coating 762 is optionally coated onto the exit foil, as illustrated in FIG. 7. Similarly, optionally a surface of the scintillation material 710 is a support surface for a fourth coating 792, as illustrated in FIG. 7. The charged particle beam state determination system 750 is further described, infra. Referring now to FIG. 7, FIG. 8, and FIG. 9A, four sheets, a first sheet 760, a second sheet 770, a third sheet 780, and a fourth sheet 790 are used to illustrated detection sheets and/or photon emitting sheets upon transmittance of a charged particle beam. Each sheet is optionally coated with a photon emitter, such as a fluorophore, such as the first sheet 760 is optionally coated with a first coating 762. Without loss of generality and for clarity of presentation, the four sheets are each illustrated as units, where the light emitting layer is not illustrated. Thus, for example, the second sheet 770 optionally refers to a support sheet, a light emitting sheet, and/or a support sheet coated by a light emitting element. The four sheets are representative of n sheets, where n is a positive integer. Referring now to FIG. 7 and FIG. 8, the charged particle beam state verification system 750 is a system that allows for monitoring of the actual charged particle beam position in real-time without destruction of the charged particle beam. The charged particle beam state verification system 750 preferably includes a first position element or first beam verification layer, which is also referred to herein as a coating, luminescent, fluorescent, phosphorescent, radiance, or viewing layer. The first position element optionally and preferably includes a coating or thin layer substantially in contact with a sheet, such as an inside surface of the nozzle foil, where the inside surface is on the synchrotron side of the nozzle foil. Less preferably, the verification layer or coating layer is substantially in contact with an outer surface of the nozzle foil, where the outer surface is on the patient treatment side of the nozzle foil. Preferably, the nozzle foil provides a substrate surface for coating by the coating layer. Optionally, a binding layer is located between the coating layer and the nozzle foil, substrate, or support sheet. Optionally, the position element is placed anywhere in the charged particle beam path. Optionally, more than one position element on more than one sheet, respectively, is used in the charged particle beam path and is used to determine a state property of the charged particle beam, as described infra. Still referring to FIG. 7 and FIG. 8, the coating, referred to as a fluorophore, yields a measurable spectroscopic response, spatially viewable by a detector or camera, as a result of transmission by the proton beam. The coating is preferably a phosphor, but is optionally any material that is viewable or imaged by a detector where the material changes spectroscopically as a result of the charged particle beam hitting or transmitting through the coating or coating layer. A detector or camera views secondary photons emitted from the coating layer and determines a position of a treatment beam 269, which is also referred to as a current position of the charged particle beam or final treatment vector of the charged particle beam, by the spectroscopic differences resulting from protons and/or charged particle beam passing through the coating layer. For example, the camera views a surface of the coating surface as the proton beam or positively charged cation beam is being scanned by the first axis control 143, vertical control, and the second axis control 144, horizontal control, beam position control elements during treatment of the tumor 720. The camera views the current position of the charged particle beam or treatment beam 269 as measured by spectroscopic response. The coating layer is preferably a phosphor or luminescent material that glows and/or emits photons for a short period of time, such as less than 5 seconds for a 50% intensity, as a result of excitation by the charged particle beam. The detector observes the temperature change and/or observe photons emitted from the charged particle beam traversed spot. Optionally, a plurality of cameras or detectors are used, where each detector views all or a portion of the coating layer. For example, two detectors are used where a first detector views a first half of the coating layer and the second detector views a second half of the coating layer. Preferably, at least a portion of the detector is mounted into the nozzle system to view the proton beam position after passing through the first axis and second axis controllers 143, 144. Preferably, the coating layer is positioned in the proton beam path 268 in a position prior to the protons striking the patient 730. Referring now to FIG. 1 and FIG. 7, the main controller 110, connected to the camera or detector output, optionally and preferably compares the final proton beam position or position of the treatment beam 269 with the planned proton beam position and/or a calibration reference to determine if the actual proton beam position or position of the treatment beam 269 is within tolerance. The charged particle beam state determination system 750 preferably is used in one or more phases, such as a calibration phase, a mapping phase, a beam position verification phase, a treatment phase, and a treatment plan modification phase. The calibration phase is used to correlate, as a function of x-, y-position of the glowing response the actual x-, y-position of the proton beam at the patient interface. During the treatment phase, the charged particle beam position is monitored and compared to the calibration and/or treatment plan to verify accurate proton delivery to the tumor 720 and/or as a charged particle beam shutoff safety indicator. Referring now to FIG. 10, the position verification system 179 and/or the treatment delivery control system 112, upon determination of a tumor shift, an unpredicted tumor distortion upon treatment, and/or a treatment anomaly optionally generates and or provides a recommended treatment change 1070. The treatment change 1070 is optionally sent out while the patient 730 is still in the treatment position, such as to a proximate physician or over the internet to a remote physician, for physician approval 1072, receipt of which allows continuation of the now modified and approved treatment plan. |
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abstract | In a mask for forming a fine pattern to completely transfer a first and a second pattern from the mask onto a receiving object, and a method of forming the mask, the mask includes a first pattern, a second pattern, and a supplemental pattern. The first pattern repeats in a first direction. The second pattern is arranged between and parallel to the first pattern and has a first width W1. The supplemental pattern is disposed between the first pattern and the second pattern, and is spaced apart by a first distance D1 in the first direction from the second pattern. |
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description | The invention relates to the field of nuclear reactor fuels. More particularly, the present invention relates to methods for making nuclear reactor fuel particles, as well as to the nuclear reactor fuel components and particles thus obtained and their use. In the search for a suitable fuel to replace the high enriched UAlx fuel generally used in Research and Materials Test Reactors (MTR) with a lower enrichment fuel, one viable candidate is found to be a U—Mo alloy. Mo is added to metallic uranium to extend the stability domain of the high temperature gamma phase, since this phase is stable under the required irradiation conditions in contrast to the room temperature alpha phase. 7-10 wt % Mo is sufficient to avoid transformation to the alpha phase during the production process. U(Mo) particles are used in the fabrication of so-called dispersion fuel plates or rods, in which the U(Mo) particles are mixed with a matrix material (generally Al). In case of a fuel plate, the compacted powder mixture is subsequently pressed in between two Al alloy plates, after which this sandwich structure is rolled to the required thickness. In case of fuel rods, fabrication may often be based on coextrusion methods. A common method to manufacture the U(Mo) particles is by atomisation processes, which can best be described as a technique in which an ingot of U(Mo) alloy is molten using arc melting while it is spinning or a variation thereof. This causes molten material to be dispersed in small droplets by the centripetal forces. The droplets solidify on their way to the cooled chamber walls. The resulting spherical particles are very well suitable for the fabrication of the dispersion fuel plates or rods. Their sizes depend on the parameters used in the melting process, but are generally around 100 μm in diameter. Another production process based on grinding of ingots results in more or less irregular ground particles of similar average dimensions. Both production processes have been used in the production of test fuel plates. Tests of U(Mo) based fuels in the reactor have revealed that the U(Mo) particles (atomised and ground) form an interaction layer with the Al matrix under irradiation. This interaction layer was demonstrated to amorphise under irradiation and shows very poor fission gas retention. This causes swelling of the fuel plates, which eventually leads to their failure by pillowing. In an attempt to remedy this behaviour, it was found that Si addition to the Al matrix results in some improvement, although it may not provide a complete solution, particularly for higher power densities. In “Dispersed (Coated particles) and monolithic (zircalloy-4 cladding) U—Mo Particles” (RERTR—2005 Meeting), Pasqualini describes CVD coating of U(Mo) particles with a silicon coating for introducing silicon as an inhibitor. Chemical vapour deposition of silicon thereby is based on silane. Furthermore, silicon is undesireable for the reprocessing of the used fuel and an alternative way, without Si, to stabilise the behaviour of the U(Mo) fuel during irradiation would be beneficial. The incorporation of neutron poisons in nuclear fuels is a frequently used method to fine-tune the characteristics of the fuel towards its use in the reactor. Neutron poisons typically may have the purpose of lowering the reactivity at the beginning of the use of a fuel assembly in the reactor. Incorporation of neutron poisons is preferably homogeneous throughout the fuel and is often accomplished by blending neutron poison powders in the matrix. Because of several reasons, eg. the higher uranium loadings required in the LEU based fuels, this blending method is less appropriate for LEU based fuels and efforts are made to incorporate the neutron poison in the structural materials of the fuel element. In “Cd wires as burnable poison for the BR2 fuel element” by Franck et al. in Transactions of RRFM 2009, it is suggested to replace the provision of neutron poisons as powder mixed in the matrix by the provision of wires of neutron poison material in the structural materials of the fuel element. It is an object of embodiments of the present invention to provide good methods for manufacturing nuclear fuel products as well as to provide good nuclear fuel products thus obtained and good use thereof. It is an advantage of embodiments according to the present invention that a flexible deposition technique for coating a variety of materials onto fuel particles for making nuclear fuel products is obtained. It is an advantage of embodiments according to the present invention that a homogeneous application of functional material can be provided to nuclear fuel particles in an efficient way, with no or only a limited influence on the nuclear fuel particle itself or the corresponding nuclear fuel product. It is an advantage of embodiments according to the present invention that deposition of functional materials can be performed at substantially low temperature, i.e. below 500° C., advantageously below 300° C., more advantageously substantially at room temperature. The latter allows providing functional material in a homogeneous manner, without hampering the properties of the nuclear fuel particle or the corresponding nuclear fuel product itself. It is an advantage of embodiments according to the present invention that the unwanted oxidation or hydriding of the fuel particles during the deposition of the functional materials can substantially be limited. It is an advantage of embodiments according to the present invention that fully tailoring the particles and thus the fuel products to the fuel needs of the reactor can be performed due to the high flexibility of the adopted coating method allowing a wide range of coating materials and thicknesses to be applied. It is an advantage of embodiments according to the present invention that coating of the fuel particles with a neutron poison can be performed, resulting in a fully homogeneously dispersion of neutron poisons in the fuel. It is an advantage of embodiments according to the present invention that the coating process can be easily controlled and up-scaled. It is an advantage of embodiments according to the present invention that the addition of foreign elements to the fuel (e.g. addition of Si to the Al matrix) can be optimised and minimised for each specific application (e.g. desired power output of the fuel). It is an advantage of embodiments according to the present invention that different types of coatings can be deposited on fuel particles, each with possible different functionalities, resulting in the possibility to optimise the fuel products. It is an advantage of some embodiments according to the present invention that both neutron poisons as well as inhibitors can be added in an efficient way, e.g. simultaneously or subsequently using the same system. It is an advantage of some embodiments according to the present invention that different types of elements can be co-deposited onto fuel particles so that different additional functionalities can simultaneously be provided to the fuel particles, resulting in an optimisation of the fuel products. It is an advantage of some embodiments according to the present invention that a combination of different coating layers of different elements can be applied to the fuel particles. Alternatively or in addition thereto, different elements having different functionality also can be applied in a single coating layer. The above objective is accomplished by a method and device according to the present invention. The present invention relates to a method for producing nuclear fuel products including fuel particles, the method comprising receiving metallic or intermetallic uranium-based fuel particle cores, providing at least one physical vapour deposited coating layer surrounding the fuel particle core and embedding the coated fuel particles in matrix material thereby forming a powder mixture of coated fuel particles and matrix material. It is an advantage of embodiments according to the present invention that physical vapour deposition is a flexible coating technique. Embedding the coated fuel particles in matrix material may comprise creating a powder dispersion, e.g. homogeneous powder dispersion, of the coated fuel particles in a solid matrix powder. Providing at least one physical vapour deposited coating layer may comprise sputtering a coating layer on the fuel particle core. The method furthermore may comprise annealing the provided coating layer. The annealing may be thermal annealing. Providing at least one physical vapour deposited coating layer comprises depositing a physical vapour deposited coating layer having a thickness between 10 nm and 2 μm, e.g. between 100 nm and 2 μm. The method may comprise compacting the mixture of coated fuel particles and matrix material. The method may comprise rolling the compacted mixture of coated fuel particles and matrix material between plates, so as to form a fuel element. The method may comprise extruding a fuel element from a mixture of coated fuel particles and matrix material. Providing at least one physical vapour deposited coating layer may comprise providing at least one physical vapour deposited coating layer comprising neutron poisons. Providing at least one physical vapour deposited coating layer may comprise providing at least one physical vapour deposited coating layer comprising inhibitor elements for inhibiting formation of an interaction layer of the nuclear fuel particle with the matrix material. Providing the at least one physical vapour deposited coating layer may comprise providing a single coating layer comprising both neutron poisons and inhibitor elements using co-deposition. Providing the at least one physical vapour deposited coating layer may comprise providing a plurality of coating layers, each layer comprising one or more elements for introducing an additional functionality to the fuel particles. The method according to embodiments of the present invention thus comprises embedding the coated fuel particles in a matrix. The matrix may be any of aluminium, silicon, magnesium, zirconium, molybdenum or a mixture or alloy thereof. The present invention also relates to a nuclear fuel product, e.g. embedded nuclear fuel particles, the nuclear fuel product comprising a powder mixture of the nuclear fuel particles and matrix material based on nuclear fuel particles embedded in the matrix material, the nuclear fuel particles comprising a metallic or intermetallic uranium-based fuel particle core and at least one physical vapour deposited coating layer surrounding the fuel particle core. It is an advantage of embodiments according to the present invention that the coating can be applied using a flexible technique, allowing surface engineering and tailoring of coatings for fuel particles and allowing new and/or improved functionality implemented on the fuel particles. A matrix material and nuclear fuel particles embedded therein may comprise a powder dispersion, e.g. homogeneous powder dispersion, of the coated fuel particles in a solid matrix powder. The at least one physical vapour deposited coating layer may be an amorphous coating layer. The at least one physical vapour deposited coating layer may have a thickness between 10 nm and 2 μm, e.g. between 100 nm and 2 μm. The matrix may be any of aluminium, silicon, magnesium, zirconium, molybdenum or a mixture thereof. The mixture of the matrix material and the fuel particles may be compacted e.g. by pressing. The at least one physical vapour deposited coating layer may comprise neutron poisons. It is an advantage of embodiments according to the present invention that neutron poisons can be applied as coating for fuel particles in a fuel product, resulting in a homogeneous provision of neutron poisons in nuclear fuel leading to an efficient functionality of the neutron poisons. It is an advantage of embodiments according to the present invention that the thickness of the coating can be tailored to have optimum effect of neutron poisons. The neutron poisons may comprise one of or a combination of B, Sm, Gd, Dy, Ag, In, Cd, Er, Hf, Eu or Ta. It is an advantage of embodiments according to the present invention that the physical vapour deposition coating allows a large flexibility in deposition of neutron poisons to be selected, allowing good tailoring for a large category of fuel particle cores and reactors. The at least one physical vapour deposited coating layer may comprise inhibitor elements for inhibiting formation of an interaction layer of the nuclear fuel particle with the matrix material and/or inhibiting the negative effects of this interaction layer formation on the behaviour of the fuel during its use. It is an advantage of embodiments according to the present invention that a coating layer of a inhibitor element can be applied to the metallic or intermetallic uranium-based particles, resulting in a homogeneous distribution of such inhibitor elements and therefore resulting in efficient inhibition of the interaction process between nuclear fuel particles and the matrix material. Inhibiting may be reducing the formation of an interaction layer as well as preventing the formation of an interaction layer or improving its properties (i.e. avoiding the detrimental effects caused by the interaction layer). The inhibitor elements may comprise one of or a combination of Si, Zr, Nb, U, Mo, Al, Ti, As, Mg, Ge, Sn, Pb, Bi, Se, Sb or Te. The inhibitor may comprise any or a combination of Group IIIa, IVa, Va and VIa elements, on rows 3, 4, 5 and 6 of the table of elements, excluding Po, P and S. The inhibitor elements may be provided as an oxide, nitride or carbide of such inhibitor elements. In some embodiments, they may be provided through direct deposition of the oxide, nitride or carbide or through reactive deposition of the elements. In some embodiments, inhibitor elements, e.g. including other inhibitor elements than cited above, either in their elemental state or as an oxide, nitride or carbide may be used, the inhibitor elements being adapted for providing a barrier between the atoms of the metallic or intermetallic uranium based fuel and the atoms of the matrix material as these become mobile, either due to temperature, ionic bombardment by fission products of the uranium or another source of mobility. For this purpose, heavier, denser compounds are advantageous. The at least one physical vapour deposited coating layer may comprise a single coating layer comprising both neutron poisons and inhibitor elements obtained by co-deposition. It is an advantage of embodiments according to the present invention that physical vapour deposition provides the flexibility of co-depositing, resulting in the possibility of obtaining an efficient coating process providing multiple additional functionalities to the fuel product. The at least one physical vapour deposited coating layer may comprise a stack of at least two layers, one layer comprising neutron poisons, another layer comprising inhibitor elements. It is an advantage of embodiments according to the present invention that the different additional functionalities for the nuclear fuel particles may be provided in different coating layers, whereby each of the layers can be tuned for optimum functionality. The at least one physical vapour deposited coating layer may be an annealed coating layer. It is an advantage of embodiments according to the present invention that thick layers can be deposited allowing full functionality and the required efficiency of the elements embedded therein. The thickness of the at least one physical vapour deposited coating layer may be in the range 5 nm to 5 μm, advantageously in the range 10 nm to 2 μm, e.g. 100 nm to 2 μm. The metallic or intermetallic uranium-based core may comprise one or a combination of uranium alloys (eg. pure U, U(Mo), U(Ti), U(Zr), U(Nb)), uranium silicides (eg. U3Si2, U3Si) or aluminides (eg. UAl3,x). It is an advantage of embodiments according to the present invention that different types of fuel particle cores can be selected, resulting in a good flexibility. The present invention furthermore relates to a nuclear fuel product, the fuel product comprising a powder mixture matrix material and fuel particles based on fuel particles embedded in the matrix material, the fuel particles comprising a metallic or intermetallic uranium-based fuel particle core and at least one coating layer surrounding the fuel particle core, the coating layer comprising neutron poisons. The neutron poisons may comprise one of or a combination of B, Sm, Gd, Dy, Ag, In, Cd, Er, Hf, Eu or Ta. A matrix material and fuel particles embedded therein may be a powder dispersion, e.g. homogeneous powder dispersion, of the nuclear fuel particles and the matrix material. The at least one physical vapour deposited coating layer may have a thickness between 10 nm and 2 μm, e.g. between 100 nm and 2 μm. The matrix may be any of aluminium, silicon, magnesium, zirconium, molybdenium or a mixture thereof. The mixture of the matrix material and the fuel particles may be compacted and rolled, e.g. between plates, for forming a fuel element. A fuel element also may be extruded using the mixture of the matrix material and the fuel particles. The at least one coating layer further may comprise inhibitor elements for inhibiting formation of an interaction layer of the nuclear fuel particle and the matrix material. The inhibitor elements may comprise one of or a combination of Si, Zr, Nb, U, Mo, Al, Ti, As, Mg, Ge, Sn, Pb, Bi, Se, Sb or Te. The inhibitor may comprise any or a combination of Group IIIa, Iva, Va and VIa elements, on rows 3, 4, 5 and 6 of the table of elements, excluding Po, P and S. The inhibitor elements may be provided as an oxide, nitride or carbide of such inhibitor elements. In some embodiments, they may be provided through direct deposition of the oxide, nitride or carbide or through reactive deposition of the elements. In some embodiments, inhibitor elements, e.g. including other inhibitor elements than cited above, either in their elemental state or as an oxide, nitride or carbide may be used, the inhibitor elements being adapted for providing a barrier between the atoms of the metallic or intermetallic uranium based fuel and the atoms of the matrix material as these become mobile, either due to temperature, ionic bombardment by fission products of the uranium or another source of mobility. For this purpose, heavier and/or denser compounds are advantageous. The at least one coating layer may comprise a single coating layer comprising both neutron poisons and inhibitor elements obtained by co-deposition. The at least one coating layer may comprise a stack of at least two layers, one layer comprising neutron poisons, another layer comprising inhibitor elements. The at least one coating layer may be an annealed coating layer. The thickness of the at least one coating layer may be in the range 10 nm to 2 μm, e.g. between 100 nm and 2 μm. The metallic or intermetallic uranium-based core may comprise one or a combination of uranium alloys (eg. pure U, U(Mo), U(Ti), U(Zr), U(Nb)), uranium silicides (eg. U3Si2, U3Si) or aluminides (eg. UAl3,x). The present invention also relates to a fuel element for generating neutrons, the fuel element comprising a plurality of nuclear fuel particles as described above embedded in a matrix material based on a powder mixture of the nuclear fuel particles and matrix material. The matrix may be a matrix comprising Al, Si, Mg, Zr, Mo. It may be a matrix made of Al, Si, Mr, Zr, Mo or a mixture thereof. The present invention also relates to a nuclear installation for generating neutrons, the nuclear installation comprising a fuel element as described above. The present invention furthermore relates to a method for producing nuclear fuel particles, the method comprising receiving metallic or intermetallic uranium-based fuel particle cores and providing at least one coating layer surrounding the fuel particle core, wherein the coating layer comprises neutron poisons. The method furthermore comprises providing a powder mixture of fuel particles and matrix material, by embedding the fuel particles in matrix material. It is an advantage of embodiments according to the present invention that physical vapour deposition is a flexible coating technique. Providing at least one coating layer may comprise physical vapour depositing such a layer, such as for example sputtering such a coating layer on the fuel particle core. The method furthermore may comprise annealing the provided coating layer. The annealing may be thermal annealing. Providing at least one coating layer may comprise providing at least one coating layer comprising inhibitor elements for inhibiting formation of an interaction layer of the nuclear fuel particle with a matrix in which the nuclear fuel particle is embeddable. Providing the at least one coating layer may comprise providing a single coating layer comprising both neutron poisons and inhibitor elements using co-deposition. Providing the at least one coating layer may comprise providing a plurality of coating layers, each layer comprising one or more elements for introducing an additional functionality to the fuel particles. The present invention furthermore relates to a nuclear fuel product, the fuel product comprising a powder mixture matrix material and fuel particles based on fuel particles embedded in the matrix material, the fuel particles comprising a metallic or intermetallic uranium-based fuel particle core and at least one coating layer surrounding the fuel particle core, the coating layer comprising inhibitor elements. The inhibitor elements may comprise one of or a combination of Si, Zr, Nb, U, Mo, Al, Ti, As, Mg, Ge, Sn, Pb, Bi, Se, Sb or Te. The inhibitor may comprise any or a combination of Group IIIa, Iva, Va and VIa elements, on rows 3, 4, 5 and 6 of the table of elements, excluding Po, P and S. The inhibitor elements may be provided as an oxide, nitride or carbide of such inhibitor elements. In some embodiments, the inhibitor element may comprise Zr or an oxide, nitride or carbide thereof. In some embodiments, the inhibitor element may be ZrN. In some embodiments, they may be provided through direct deposition of the oxide, nitride or carbide or through reactive deposition of the elements. In some embodiments, inhibitor elements, e.g. including other inhibitor elements than cited above, either in their elemental state or as an oxide, nitride or carbide may be used, the inhibitor elements being adapted for providing a barrier between the atoms of the metallic or intermetallic uranium based fuel and the atoms of the matrix material as these become mobile, either due to temperature, ionic bombardment by fission products of the uranium or another source of mobility. For this purpose, heavier and/or denser compounds are advantageous. A matrix material and fuel particles embedded therein may be a powder dispersion, e.g. homogeneous powder dispersion, of the nuclear fuel particles and the matrix material. The at least one physical vapour deposited coating layer may have a thickness between 10 nm and 2 μm. The matrix may be any of aluminium, silicon, magnesium, zirconium, molybdenium or a mixture thereof. The mixture of the matrix material and the fuel particles may be compacted and rolled, e.g. between plates, for forming a fuel element. A fuel element also may be extruded using the mixture of the matrix material and the fuel particles. The at least one coating layer further may comprise a neutron poison element. The neutron poisons may comprise one of or a combination of B, Sm, Gd, Dy, Ag, In, Cd, Er, Hf, Eu or Ta. The at least one coating layer may comprise a single coating layer comprising both neutron poisons and inhibitor elements obtained by co-deposition. The at least one coating layer may comprise a stack of at least two layers, one layer comprising neutron poisons, another layer comprising inhibitor elements. The at least one coating layer may be an annealed coating layer. The thickness of the at least one coating layer may be in the range 10 nm to 2 μm. The metallic or intermetallic uranium-based core may comprise one or a combination of uranium alloys (eg. pure U, U(Mo), U(Ti), U(Zr), U(Nb)), uranium silicides (eg. U3Si2, U3Si) or aluminides (eg. UAl3,x). The product may be a nuclear fuel element or may be processed to a nuclear fuel element. The present invention also relates to a nuclear installation comprising such a product. The present invention furthermore relates to a method for producing nuclear fuel particles, the method comprising receiving metallic or intermetallic uranium-based fuel particle cores and providing at least one coating layer surrounding the fuel particle core, wherein the coating layer comprises inhibitor elements. The method furthermore comprises providing a powder mixture of fuel particles and matrix material, by embedding the fuel particles in matrix material. It is an advantage of embodiments according to the present invention that physical vapour deposition is a flexible coating technique. Providing at least one coating layer may comprise physical vapour depositing such a layer, such as for example sputtering such a coating layer on the fuel particle core. The method furthermore may comprise annealing the provided coating layer. The annealing may be thermal annealing. Providing at least one coating layer may comprise providing at least one coating layer comprising neutron poisons. Providing the at least one coating layer may comprise providing a single coating layer comprising both neutron poisons and inhibitor elements using co-deposition. Providing the at least one coating layer may comprise providing a plurality of coating layers, each layer comprising one or more elements for introducing an additional functionality to the fuel particles. Particular and preferred aspects of the invention are set out in the accompanying independent and dependent claims. Features from the dependent claims may be combined with features of the independent claims and with features of other dependent claims as appropriate and not merely as explicitly set out in the claims. These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter. Any reference signs in the claims shall not be construed as limiting the scope. The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein. It is to be noticed that the term “comprising”, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression “a device comprising means A and B” should not be limited to devices consisting only of components A and B. Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments. Similarly it should be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention. Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination. In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description. The invention will now be described by a detailed description of several embodiments of the invention. It is clear that other embodiments of the invention can be configured according to the knowledge of persons skilled in the art without departing from the true spirit or technical teaching of the invention, the invention being limited only by the terms of the appended claims. Where in embodiments of the present invention the term intermetallic is used, reference is made to a material comprising two or more metallic components bound to each other. Where in embodiments according to the present invention reference is made to “embedded in” reference is made to material lying in surrounding matter. Such embedding may e.g. be a providing a powder dispersion. A first material being embedded in a second material nevertheless does not only refer to a dispersion or mixture, but e.g. also to a compacted mixture, an extruded product of a mixture, etc. In a first aspect, the present invention relates to a method for producing or processing nuclear fuel products. The nuclear fuel products according to embodiments of the present invention comprise “metallic or intermetallic uranium”-based particles. The nuclear fuel products according to embodiments of the present invention are embedded in a matrix material thereby forming a powder mixture of fuel particles and matrix material. Embedding may e.g. comprise creating a powder dispersion, although embedding is not limited thereto. The method according to embodiments of the present invention comprises receiving metallic or intermetallic uranium-based fuel particle cores, providing, using physical vapour deposition, a coating surrounding the fuel particle core and embedding the particles in a matrix for forming a mixture of coated fuel particles and solid matrix material. The coating applied with physical vapour deposition may provide a predetermined functionality to the fuel particle, such as for example providing a neutron poisoning effect homogeneously spread in the fuel to lower a high reactivity of initial fresh fuel loads, or for example providing an inhibition effect for interaction or interdiffusion between metallic or intermetallic uranium-based particles and a matrix in which they are used, e.g. interaction between U(Mo) and an Al matrix. Using physical vapour deposition allows efficient and good deposition of coating layers, with appropriate flexibility. Further features and advantages will now be illustrated by way of an exemplary method according to an embodiment of the present invention for which a flow diagram is illustrated in FIG. 1, embodiments of the present invention not being limited by this exemplary method. In a first step, the method comprises receiving metallic or intermetallic uranium-based fuel particle cores. Such receiving may encompass obtaining the metallic or intermetallic uranium-based fuel particle cores e.g. commercially by buying it from the shelve. Commercially available particles are for example U(Mo) particles as available from the Korean Atomic Energy Research Institute (KAERI). Alternatively, the metallic or intermetallic uranium-based fuel particle cores also may be obtained by manufacturing such particles. One example thereof, the present invention not being limited thereto, is production of metallic or intermetallic uranium-based fuel particle cores using a rotating-disk centrifugal atomization process. Metallic or intermetallic uranium particles and alloying metals can for example be melted in a crucible and fed on a rotating disk. On the rotating disk, fine droplets of the melted substance can cool rapidly, e.g. in an inert atmosphere, resulting in substantially spherical particles. An example of such a production method is also described in U.S. Pat. No. 5,978,432, embodiments of the present invention not being limited to this production method for uranium-based cores. One alternative production method is for example based on grinding of the fuel ingots, thus producing ground fuel as opposed to atomised. The diameter of the metallic or intermetallic uranium-based particles is not limiting for the present invention. Typical particle core diameters that e.g. can be used are in the range 50 μm to 100 μm, although the invention is not limited thereto and larger particles also may be used if these become available. Larger particles have the advantage that the surface to volume ratio decreases, resulting in more efficient particles. The metallic or intermetallic uranium-based particles may be uranium alloys, which may for example be gamma-stabilised uranium whereby the alloys are used for stabilising the gamma phase of the uranium. Stabilisation thereby is performed against swelling under irradiation. The metallic or intermetallic uranium based particles may be atomised particles as well as ground particles. Explicit examples of particles that can be used are one or a combination of uranium alloys (eg. pure U, U(Mo), U(Ti), U(Zr), U(Nb)), uranium silicides (eg. U3Si2, U3Si) or aluminides (eg. UAl3,x). One particular example, used as lower enrichment fuel, is U(Mo) alloy wherein Mo is added to metallic uranium to extend the stability domain of the high temperature gamma phase and whereby 7 to 10 wt % is typically considered sufficient to avoid transformation to the alpha phase during the production process. In a second step, the method comprises providing at least one coating layer to the metallic or intermetallic uranium-based fuel particle using a physical vapour deposition technique. Physical vapour deposition relates to deposition techniques performed in vacuum whereby condensation of a vaporized form of material. In one advantageous embodiment, the physical vapour deposition technique used is sputtering. Embodiments of the present invention nevertheless are not limited thereto and alternative physical vapour deposition techniques also may be applied, such as for example evaporative deposition, e-beam deposition, cathodic arc deposition, pulsed laser deposition, thermal evaporation, etc. Typical deposition conditions that could be used—although the invention is not limited thereto—may comprise a basic pressure of an the order of 10−6 mbar and the system being backfilled with high purity argon to a pressure of 10−3 to 10−2 mbar at room temperature. It is an advantage of some embodiments according to the present invention that deposition can be performed in a controlled manner at a temperature below 500° C., advantageously at a temperature below 300° C., more advantageously substantially at room temperature. The latter avoids oxidation or other reactions of the fuel particles during the coating deposition and transformation of the particles from their gamma phase to the alpha phase. It is an advantage of some embodiments according to the present invention that deposition can be performed without exposure of the particles to hydrogen or gases that liberate hydrogen (eg. silane). In one embodiment, the method may comprise sputtering a coating on the nuclear fuel particle cores. In one example, sputtering may be performed by providing an amount of nuclear fuel particle cores in a system comprising a system for agitation, e.g. constant agitation, of the nuclear fuel particle cores, such as through a rotating drum or vibration, and coating the particles substantially uniform over their surface by rotating or vibrating the particles such that different portions of their surface are subject to the sputter coating source. More generally, embodiments of the present invention benefit from systems wherein the fuel particles are moved during the physical vapour deposition step, so that different portions of their surface are subject to the sputter coating source. Such techniques allow to obtain a layer surrounding the coating with a substantially fixed thickness. Techniques employing movement of the particles for reaching a substantially homogeneous coating for volumetric items, such as fuel particles, are known to the person skilled in the art. One or more coating layers may be applied, for example to achieve a double functionality or to achieve an improved functionality by combining different materials. In some embodiments, the coating consists of a single layer comprising a single element of interest to invoke an effect on the particles or on their use. In a first exemplary embodiment, the coating layer comprises an inhibitor for inhibiting, stabilizing and/or reducing the formation of an interaction layer or for improving the properties of the interaction layer. Inhibitors that may be used for this are those materials having an inhibiting stabilizing and/or reducing effect on the formation of an interaction layer between the metallic or intermetallic uranium-based fuel core and a matrix wherein the particles will be embedded. The inhibition problem has for example been discussed in more detail by Park et al. in Journal of Nuclear Materials 374 (2008) 422-430. The inhibitor may be a barrier and/or stabilizing element. A typical example wherein such inhibitors may play an important role is for U(Mo) particles in an aluminum matrix, although embodiments of the invention are not limited thereto. The inhibitors used may be metals, but can also be used in their oxide, nitride or carbide form. Some examples of inhibitors that may be used are Si, Zr, Nb, U, Mo, Ti, etc. The thickness of the layer to be applied will depend on the amount of the inhibitor required to stabilise or prevent any interaction between the metallic or intermetallic uranium-based fuel core and the matrix and can be tuned or optimized accordingly. If for example in the case of U(Mo) in an aluminum matrix, silicon is used as an inhibitor, the thickness of the layer advantageously may be in the range 100 nm to 2 μm, e.g. between 300 nm and 1 μm. In one particular example, the thickness may be about 600 nm. In another example, in the case of U(Mo) in an aluminum matrix, zirconium nitride is used as an inhibitor, the thickness of the layer advantageously may be in the range 100 nm to 2 μm, e.g. between 300 nm and 1 μm. In one particular example, the thickness may be about 1000 nm. More generally, the thickness of layers comprising inhibitors may be in the range 5 nm to 5 μm, more preferably in the range 10 nm to 2 μm, e.g. 100 nm to 2 μm. Although the required concentration of inhibitors depends on the inhibitor and the way it influences both the mechanism of interaction layer formation and the properties of the interaction layer, the required inhibitor concentration, when e.g. Si is used, may in one example be set between 1 vol % and 10 vol % of the matrix volume. The lower limit may be determined by the concentration whereby the interaction layer shows a stable behaviour under irradiation and whereby the growth of the interaction layer , thanks to this inhibitor content, does not exceed the volume where the inhibitor concentration would fall below that lower limit during the life of the fuel. The upper limit may be selected so that it does not exceed e.g. 10 vol % of the matrix, because the inhibitor influence on the fuel element itself should be kept to a minimum. It is an advantage of embodiments according to the present invention that the inhibitors are added so they can be used in an efficient way, allowing minimization of the added inhibitor concentration, while still obtaining the required functionality. It is an advantage of coating of the fuel particle cores, that the inhibitors are appropriately homogeneously distributed around the cores, such that optimum inhibition, stabilization and/or reduction can take place. The presence of the coating layer in a reactor can provide a sufficient influx of inhibitor material into the interaction layer between the metallic or intermetallic uranium based fuel particle core and the matrix to stabilize the behaviour of the interaction layer and its rate of formation. In some embodiments, the presence of the coating layer in a reactor can also provide a barrier for the direct interaction between the uranium in the fuel particle and the matrix material by inhibiting all contact between these two materials, even as these materials diffuse under the influence of temperature, ion bombardment by the fission products of the uranium, or other causes for diffusion. In a second exemplary embodiment, the coating comprises neutron poisons. Neutron poisons advantageously are materials with large neutron absorption cross-section. They provide the functionality of reducing high reactivity to initial fresh fuel load and advantageously, by depletion when they absorb neutrons during reactor operation, lose functionality so that the overall reactivity of the reactor is more constant. Examples of neutron poisons that may be used are B, Sm, Gd, Dy, Ag, In, Cd, Er, Hf, Eu, Ta, etc. The required layer thickness for obtaining the appropriate neutron poison effect depends on the particle size and the neutron poison cross section, as well as on the requirements of the reactor. By way of illustration, the neutron poison cross section for different materials as function of the neutron energy is shown in FIG. 2. In one example, the thickness of the layer may be selected such that a quantity between 0.1 and 2 weight percent with respect to the total uranium-235 mass is present. Some examples of neutron poison coating layers then may have a resulting thickness in the range 100 nm to 200 nm. Nevertheless, the required neutron poison effect may be different for different fuel particle cores, and the thickness of the neutron poison coating layer may be adapted to tune to the required neutron poison effect. The latter can be e.g. performed by test depositions for the fuel particle core envisaged. In a second set of embodiments, the coating may comprise more than one element of interest, either to invoke an improved effect on the particles or on their use. In one particular embodiment, a single layer comprising different materials invoking different effects may be deposited around the fuel particle core. For example a combination of an inhibition element and a neutron poisoning element may be provided in a single layer. It thereby is an advantage of physical vapour deposition processes that these are flexible in allowing co-deposition, i.e. they can be easily configured for co-deposition of the different materials e.g. by using multiple deposition sources, by using a source material comprising different materials, etc. In the particular example of a coating combining inhibitors with neutron poison material a combination of materials as described above can be used, whereby the neutron poison material may be introduced in the layer as dopant, substantially not altering the properties of the inhibitor coating layer. In another particular embodiment, a stack of coating layers may be provided, whereby different layers provide different functionality to the coating and the corresponding coated fuel articles. In some examples, a stack of an inhibitor coating layer and a coating layer comprising neutron poisons is used to invoke both inhibition and neutron poisoning effects. The overall thickness of the stack advantageously may be in the range 50 nm to 5 μm, more preferably in the range 100 nm to 2 μm. In one example, the neutron poison materials also may have interaction inhibition functionality. The latter may result in a reduction of the thickness of the inhibitor coating layer. In an optional third step, post processing of the coating may be performed. One example of a post processing step that may be applied is annealing. Annealing may be performed at temperatures between 400° C. and 1100° C., e.g. between 500° C. and 1000° C. It may be performed at normal pressure in an inert atmosphere, e.g. in an argon or helium gaseous environment. The annealing time may be in the range of a couple of seconds to one or more hours, e.g. in the range 1 minute to 1 hour. Such annealing may result in the formation of compounds between uranium and the coating. Another post processing step, which may inherently be performed during use of the fuel articles, may be irradiation. The latter may result in formation of compounds between uranium and the coating and may be less subject to oxidation, phase transformation and alteration of the microstructure of the fuel particle core. In another step, the method furthermore comprises embedding the particles in a matrix thereby forming a powder mixture of fuel particles and matrix material. Embedding thereby may be creating that fuel particles are lying in surrounding matrix material. In some embodiments a powder dispersion of the fuel particles and the solid matrix powder material is created by the embedding. The mixing advantageously may be done using particles with a diameter within a certain selected range, in order to obtain a homogeneous dispersion of the particles in the matrix material. If the particles do not yet have a diameter within this range, the latter can for example be obtained by performing granulometric selection. Particles with appropriate size may then be mixed by mixing the particles and the matrix material. In one embodiment, embedding the fuel particles in a matrix material may be obtained by providing the two components in a recipient and mixing the components. Such mixing may be performed by manually or mechanically mixing, such as steering, shaking, magnetically steering, . . . , techniques that are well known to the person skilled in the art. The mixed material may be used for producing a fuel element. The method therefore also may comprise compacting the material, e.g. by pressing the material into a compact and eventually processing the compact into a fuel element, e.g. in the shape of a rod or a plate. In one embodiment, compacting the material may be obtained by pressing. Different types of pressing setups are available on the market, the compacting not particularly being limited by the pressing technique. Processing into a fuel element may comprise, in one embodiment, hot rolling technique, e.g. of the powder mixture in between two plates. Hot rolling techniques applied may correspond with the techniques available in the field. E.g. in some embodiments a plate like material may be obtained by laminating the pressed mixture between two plates of aluminium and optionally also providing aluminium portions at the edges surrounding the mixture and then hot rolling of the material to get a thin plate. Alternatively also rods or other shaped elements can be formed. In one particular example, the pressed compact of the powder mixture of coated fuel particles and matrix material is placed in an Al alloy picture frame between two Al alloy plates, after which the sandwich structure is rolled to the required thickness for forming a fuel element. The matrix wherein the coated fuel particles are embedded may be e.g. an aluminium, silicon, magnesium, zirconium or molybdenum matrix, or a matrix being made of a mixture/alloy of these elements. The matrix may be pure, but can also be the above identified materials mixed with other materials, such as inhibitors or neutron poisons. In some embodiments, the method comprises an additional step of providing an intermediate coating for improving the adhesion of one coating layer on the fuel particle core or on another coating layer. In one example, Ti or Zr interlayers may be provided for improving adhesion of one layer on the core or on another layer. The interlayer may have a thickness of a few nanometre. An outer coating corresponding to the matrix material in which the particles are to be embedded can also be applied to improve the adhesion of the coated fuel particles to the matrix. In one example a Ti or Zr interlayer is used between the U(Mo) fuel particle core and the Si overlayer resulting in an improved adhesion of the Si overlayer on the fuel particle core. In another example an outer Al coating is applied to the coated U(Mo) fuel particle resulting in an improved adhesion of the coated fuel particle to the Al matrix in which the particle is embedded. Production of such outer- or interlayers may be easy due to the flexibility of the production technique. In a second aspect, the present invention relates to a nuclear fuel product comprising a matrix and nuclear fuel particles for use in nuclear reactors. According to embodiments of the present invention, the nuclear fuel product comprises a powder mixture of matrix material and nuclear fuel particles based on fuel particles being embedded in the matrix material, the nuclear fuel particles comprising a metallic or intermetallic uranium-based fuel particle core and at least one physical vapour deposited coating layer, surrounding the fuel particle core. A matrix material and nuclear fuel particles embedded therein may comprise a powder dispersion, e.g. homogeneous powder dispersion, of the coated fuel particles in a solid matrix powder. The coated particles advantageously may be made according to an embodiment of the first aspect of the present invention, although embodiments of the second aspect are not limited thereto. The metallic or intermetallic uranium- based particles may be uranium alloys, which may for example be gamma-stabilised uranium whereby the alloying elements are used for stabilising the gamma phase of the uranium. Stabilisation thereby is performed against swelling under irradiation. The metallic or intermetallic uranium based particles may be atomised particles as well as ground particles. Explicit examples of particles that can be used are one or a combination of uranium alloys (pure U, U(Mo), U(Ti), U(Zr), U(Nb)), uranium silicides (eg. U3Si2 U3Si) or aluminides (eg. UAl3,x). The diameter of the metallic or intermetallic uranium-based particles is not limiting for the present invention. Typical particle core diameters that e.g. can be used are in the range 50 μm to 100 μm, although the invention is not limited thereto and larger particles also may be used if these become available. Larger particles have the advantage that the surface to volume ratio decreases, resulting in more efficient particles. The matrix material wherein the coated fuel particles are embedded may be e.g. an aluminium, silicon, magnesium, zirconium or molybdenum matrix, or a matrix being made of a mixture/alloy of these elements. The matrix may be pure, but can also be the above identified materials mixed with other materials, such as inhibitors or neutron poisons. The at least one coating layer is deposited with a physical vapour deposition technique, such as for example sputtering, e-beam evaporation, thermal evaporation, cathodic arc deposition, pulsed laser deposition, thermal evaporation, etc. The physical vapour deposited coating layer may be made by physical vapour deposition at low temperature, e.g. below 500° C., e.g. below 300° C., e.g. substantially at room temperature, thus in some embodiments resulting in a physical vapour deposited coating layer that is substantially amorphous as could be established using XRD. In some embodiments, e.g. when using ZrN, the coatings deposited using physical vapour deposition may be nanocrystalline. Embodiments of the present invention may comprise a single coating layer or a multiple of coating layers, providing one or optionally more functionalities to the particles or their use. The at least one coating layer may comprise an inhibitor for inhibiting, stabilizing and/or reducing the formation of an interaction layer or for improving the properties of the interaction layer. Inhibitors and layers comprising such inhibitors may be as described in embodiments of the first aspect. The at least one coating layer may in addition or alternative to inhibitors comprise neutron poisons. Neutron poisons advantageously are materials with large neutron absorption cross-section. They provide the functionality of reducing high reactivity to initial fresh fuel load and advantageously, by depletion when they absorb neutrons during reactor operation, lose functionality so that the overall reactivity of the reactor is more constant than without neutron poisons. Neutron poisons and the layers comprising them may be as described in embodiments of the first aspect. Different materials with different functionality may be co-deposited resulting in a mixed single coating layer, or they may be deposited as a stack of layers. The fuel particles may be annealed, using a process as described in the first aspect. Other features and advantages also may be as those described or stemming from manufacturing method embodiments of the first aspect. In some embodiments, an intermediate layer for improving the adhesion may be provided between the core and the coating layers, e.g. inhibitor or neutron poison layer(s), or in between different layers of a coating stack, or between the matrix and the surface of the outer coating layer. In one example, Ti or Zr interlayers may be provided for improving adhesion of one layer on the core or on another layer. The interlayer may have a thickness of a few nanometer. In one example a Ti or Zr interlayer is used between the U(Mo) fuel particle core and the Si overlayer resulting in an improved adhesion of the Si overlayer on the fuel particle core. In another example, an outer Al coating layer may be applied to improve the compatibility and adhesion of the coated particles and the Al matrix in which they are embedded. In a third aspect, a nuclear fuel product for use in nuclear reactors or nuclear reactor fuel is described wherein the nuclear fuel product comprises a powder mixture of matrix material and nuclear fuel particles, based on fuel particles being embedded in the matrix material, the nuclear fuel particles comprising a metallic or intermetallic uranium-based fuel particle core and at least one coating layer comprising neutron poisons. A matrix material and nuclear fuel particles embedded therein may comprise a powder dispersion, e.g. homogeneous powder dispersion, of the coated fuel particles in a solid matrix powder. The latter results in the advantage of having a homogeneous distribution of neutron poisons inside the fuel element, resulting in a more efficient neutron poisoning effect. The coated particles advantageously may be made according to an embodiment of the first aspect of the present invention, although embodiments of the third aspect are not limited thereto. Other features and advantages also may be as those described or stemming from manufacturing method embodiments of the first aspect. In a fourth aspect, a nuclear fuel product for use in nuclear reactors or nuclear reactor fuel is described wherein the nuclear fuel product comprises a powder mixture of matrix material and nuclear fuel particles, based on fuel particles being embedded in the matrix material, the nuclear fuel particles comprising a metallic or intermetallic uranium-based fuel particle core and at least one coating layer comprising inhibitor elements. A matrix material and nuclear fuel particles embedded therein may comprise a powder dispersion, e.g. homogeneous powder dispersion, of the coated fuel particles in a solid matrix powder. The latter results in the advantage of having a homogeneous distribution of inhibitor elements inside the fuel element and accurately surrounding the core fuel particle material and accurately chemically isolting it from the matrix material. The inhibitor elements may comprise one of or a combination of Si, Zr, Nb, U, Mo, Al, Ti, As, Mg, Ge, Sn, Pb, Bi, Se, Sb or Te. The inhibitor may comprise any or a combination of Group IIIa, Iva, Va and VIa elements, on rows 3, 4, 5 and 6 of the table of elements, excluding Po, P and S. The inhibitor elements may be provided as an oxide, nitride or carbide of such inhibitor elements. In some embodiments, the inhibitor element may comprise Zr or an oxide, nitride or carbide thereof. In some embodiments, the inhibitor element may be ZrN. In some embodiments, they may be provided through direct deposition of the oxide, nitride or carbide or through reactive deposition of the elements. In some embodiments, inhibitor elements, e.g. including other inhibitor elements than cited above, either in their elemental state or as an oxide, nitride or carbide may be used, the inhibitor elements being adapted for providing a barrier between the atoms of the metallic or intermetallic uranium based fuel and the atoms of the matrix material as these become mobile, either due to temperature, ionic bombardment by fission products of the uranium or another source of mobility. For this purpose, heavier and/or denser compounds are advantageous. Inhibitor elements are selected such that they do not interact with the particle fuel core and the matrix. The coated particles advantageously may be made according to an embodiment of the first aspect of the present invention, although embodiments of the fourth aspect are not limited thereto. Other features and advantages also may be as those described or stemming from manufacturing method embodiments of the first aspect. In a fifth aspect, the present invention relates to a fuel element for generating neutrons, wherein the fuel element comprises a powder mixture of a plurality of nuclear fuel particles in matrix material, based on the fuel particles being embedded in a matrix material as described in embodiments of the second, third or fourth aspect. A matrix material and nuclear fuel particles embedded therein may comprise a powder dispersion, e.g. homogeneous powder dispersion, of the coated fuel particles in a solid matrix powder. Furthermore, a nuclear installation comprising such a fuel element also is envisaged. Such nuclear installations could include test reactors, propulsion reactors, etc. Such a fuel element may be a plate, rod, tube. The fuel elements may be made using extrusion or coextrusion techniques using the powder mixture of matrix material and fuel particles or may be obtained through rolling of compacted powder mixture of matrix material and fuel particles, e.g. using a lamination between plates. In a sixth aspect, the present invention also relates to a method for producing or processing nuclear fuel products comprising a matrix and fuel particles embedded therein. The nuclear fuel particles according to embodiments of the present invention are “metallic or intermetallic uranium”-based particles, although embodiments of the invention are not limited thereto. The method according to embodiments of the present invention comprises receiving metallic or intermetallic uranium-based fuel particle cores, providing a coating surrounding the fuel particle core wherein the coating comprises neutron poisons and embedding the particles in a matrix so as to obtain a powder mixture of fuel particles and matrix material. Embedding nuclear fuel particles in a matrix material may comprise providing a powder dispersion, e.g. homogeneous powder dispersion, of the coated fuel particles in a solid matrix powder. It is an advantage of embodiments according to the present aspect that a homogeneous distribution of neutron poisons is provided and that an efficient effect of neutron poisoning can be obtained in a nuclear reactor. The methods used for depositing the at least one coating are not necessarily restricted to physical vapour deposition methods, but deposition also could be performed using other methods such as for example chemical vapour deposition or fluidised bed chemical vapour deposition. Use of physical vapour deposition may be advantageous as it, amongst others, allows deposition at low temperature, provides flexibility. Further features and advantages of embodiments according to the fifth aspect may be as set out in embodiments of the first aspect. In a seventh aspect, the present invention also relates to a method for producing or processing nuclear fuel products comprising a matrix and fuel particles embedded therein. The nuclear fuel particles according to embodiments of the present invention are “metallic or intermetallic uranium”-based particles, although embodiments of the invention are not limited thereto. The method according to embodiments of the present invention comprises receiving metallic or intermetallic uranium-based fuel particle cores, providing a coating surrounding the fuel particle core wherein the coating comprises inhibitor elements and embedding the particles in a matrix so as to obtain a powder mixture of fuel particles and matrix material. Embedding nuclear fuel particles in a matrix material may comprise providing a powder dispersion, e.g. homogeneous powder dispersion, of the coated fuel particles in a solid matrix powder. It is an advantage of embodiments according to the present aspect that a homogeneous distribution of inhibitor elements inside the fuel element and accurately surrounding the core fuel particle material and accurately chemically isolting it from the matrix material. The methods used for depositing the at least one coating are not necessarily restricted to physical vapour deposition methods, but deposition also could be performed using other methods such as for example chemical vapour deposition or fluidised bed chemical vapour deposition. Use of physical vapour deposition may be advantageous as it, amongst others, allows deposition at low temperature, provides flexibility. Further features and advantages of embodiments according to the fifth aspect may be as set out in embodiments of the first aspect. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure and the appended claims. For example, the present invention also relates to the use of the products as fuel assembly or fuel element or for producing such fuel assemblies or fuel elements. The present invention also relates to the use of products in a nuclear installation. |
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048428132 | description | DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIG. 1, a pressurized water reactor 1 includes a pressure resistant vessel 2 containing a coolant closed by a removable cover 3, coolant inlet nozzles 4 and coolant outlet nozzles 5, a core 6 with a lower supporting plate 7 perforated with holes 8 for allowing coolant to pass therethrough upwardly into the fuel assemblies 9 and clusters 10 of control elements vertically movable by drive shafts 11 through the cover 3 of reactor 1. The reactor also includes upper internal equipments 12 located between the core 6 and the cover 3. A cylindrical external barrel 13, spaced from the internal surface 14 of vessel 2 and having an upper collar 15 maintained between cover 3 and vessel 2, drives the coolant flow entering through inlet nozzle 4 and directs it along the inner surface 14 of the vessel 2 so that it penetrates into the core 6 through the low part of the assemblies 9. Passage means 16 at the level of the collar 15 are provided for by-passing the core, a small part of the coolant. The coolant is directed to a volume 17 defined by the cover 3 of the reactor 1 and by the top part 18 of the upper internal equipments 12 of the reactor. A plenum chamber 19 collects the coolant coming out of the core and directs it transversely towards the coolant outlet nozzle 5, out of the vessel. The coolant traverses the cylindrical barrel 13 through holes 20 disposed in line with the outlet nozzles 5. Guiding tubes 21 guide the drive shafts 11 of clusters 10 through the chamber 19 and protect said drive rods from coolant turbulences. The upper internal equipments 12 further include separating means or device 22 having guides 23 for clusters 10 and for the shafts 11. The separating device is disposed between the core 6 and the plenum chamber 19. Said device 22 further comprise a lower plate 24 perforated with holes 25 allowing the coolant to flow from the core 6 into said device 22, and with holes 26 for movement of clusters 10 and their control rods 11 through the lower plate into an out of the assemblies 9 of the core. The device 22 has an upper plate 27 perforated with holes 28 for the coolant to pass into the chamber 19 and holes 29, placed in line with the guiding tubes 21 of the drive shafts 11 of clusters of control elements. Both plates of the device 22 are connected together at their periphery by an envelope 30 therefore forming an enclosure. The envelope constitutes the radial external limit of the separating device 22. A minimum clearance between device 22 and the cylindrical external barrel 13 is provided. Spacer tubes 31 connect together the coolant passage holes 25 of the lower plate 24 with the coolant passage holes 28 of the upper plate 27 and are disposed between the cluster guides 23. The cluster guides 23 may preferably be open mechanically welded, tubular units formed by perforated plates or "guide cards" 32 spaced apart by continuous guide sleeves 33 and square bars 34 extending over and along the whole height of the cluster guides (FIG. 5). FIGS. 4 and 5 show a preferred embodiment with spacer tubes 31 disposed according to a triangular pitch. The spacer tubes are symetrically disposed at the six apices of a hexagon, the center of each hexagon being located on the axis of a corresponding cluster guide 23. FIG. 5 shows more particularly in cross-section one half of a "card" 33 and three of its six associated spacer tubes 31. The cluster guide 23 is in radial abutment against each of the six surrounding tubes through bosses 35 spaced apart along the tubes; it is fixed in a way known perse to the upper plates 27 of device 22. FIG. 7 shows a partial top view of the upper plate 27. The cluster guide 23 is shown schematically by its dotted contour. It is rigidly fixed by means of three screws 39 to plate 27. Hole 29 is for the passage of the drive rod 11 of the cluster guided by the cluster guide 23. In the embodiment shown by way of non limitative example of FIG. 6, the cluster guide 23 is centered resiliently and may expand into the lower plate 24, being slidely fitted in holes 26. These holes receive from underneath the upper end pieces 37 of the corresponding fuel assemblies 9. The spacer tubes 31 are moreover rigidly fixed thereto by screws 36 in the lower plate 24. Reinforcements 38 are finally formed in the low part of the spacer tubes 31 conveying the coolant. In another preferred embodiment of the invention, the separating means 22 form the lower part of the upper internal equipment 12 suspended by its collar 15 supported by the vessel and pressurely maintained by the cover 3. External cooling water may be introduced by water coolant injection means 40 directly into the separating means through at least one pipe 41 whose outlet is advantageously located in proximity of the lower part of the separating means, near the upper part of the core. According to the invention, the internal equipments of the reactor 1 further include probe guiding means or device 42 for guiding elongated probes into and out of the core through the lower part 43 of the fuel assemblies 9. This device includes probe guide ducts 44 each intended to receive at least one elongated probe (not shown). These guide ducts 44 sealingly penetrate the vessel 2 of the reactor 1 through sleeves 45 shown with dotted lines on FIG. 1 and on FIG. 3. These sleeves 45 are situated above the coolant inlet 4 and outlet 5 nozzles. Ducts 44 then extend downwardly to below the lower plate of core 7 along the external barrel 13 which fixedly supports said tubes, the clearance existing between device 22 and said barrel allowing their passage. Fluid tightness of plate 24 with respect to barrel 13 is carefully provided so as to prevent the coolant coming from the assemblies from taking the path existing between the envelope 30 and barrel 13. The volume which is defined there is relatively tranquilized. The guide ducts 44 are then transversely distributed are directed for traversing the supporting plate 7 of the core from underneath and for terminating in close proximity of the lower part of the assemblies 9. For removing and engaging an enlongated probe from the outside of the reactor, a sufficient value for the radii of curvature is provided for the guide ducts 44. In a preferred embodiment of the invention, the lower part of the lower internal equipments 46 includes an enclosure formed by the lower support plate 7 of the core and a wall 47 perforated with coolant passage holes 48. Ducts 49 connect said passage holes 8 in wall 47 to lower plate 8 and channel the coolant toward the core. A volume 51 protects from turbulences is thus defined, in which the probe guide ducts 44 are distributed before terminating in close proximities of the lower part of the assemblies. The enclosure is filled through holes 50 formed for this purpose in wall 47 and air purged during the initial filling of the reactor by means provided in the support plate of the core. Normal operation of the nuclear reactor with internal equipments such as described in the invention is described hereafter. Black arrows on FIGS. 1 and 2 indicate the path followed by the main coolant flow in the reactor. The cold coolant enters reactor 1 through the inlet nozzles 4. The main coolant flow is deflected by external barrel 13 and for its most part downwards to the bottom of the reactor wherein it penetrates into the ducts 49 through which it flows before upwardly traversing the assemblies 9 of the core 6 of the reactor. The flow of coolant coming from each assembly is then deflected by the upper end piece 37 of said assembly towards the inlet holes 25 of the spacer tubes 31 of device 22. The collant flow, heated by the core, then traverses device 22 through said tubes 31 and arrives in the plenum chamber 19 where it is again deflected transversely among the guide tubes 21 of drive shafts 11 toward the outlet nozzles 5 after traversing the cylindrical barrel 13 through holes 20 disposed in line with the outlet nozzles. The coolant coming from the assemblies is therefore isolated along all its travel path, from the coolant volumes surrounding the clusters and their drive shafts contained in device 22 and in guide tubes 21. These volumes are directly connected to the capacity 17 situated under the cover of the reactor. This capacity is overpressurized with respect to the coolant leaving the assemblies. Therefore an axial downward current, shown by white arrows in FIGS. 1 and 2, is existing in tubes 21 and device 22. This downward current constitutes an aid to clusters falling which is an important safety advantage. It may also provide cooling of the clusters if some of them are for example fertile clusters as in case of spectrum variation reactors. Passage means 16 at the level of collar 15 of the cylindrical barrel 13 are provided to direct a reduced cold coolant flow coming from the inlet nozzle, toward capacity 17 situated under the cover of the reactor. This is indicated on FIG. 1 by a thin black arrow. During a reactor shutdown for refueling, the device for guiding the elongated probes does not need to be removed when the upper internal equipements are removed for access to the fuel assemblies. The probe guide ducts 44 penetrates into the vessel through sleeves 45 located under the inlet and outlet coolant nozzles. Then, they are supported by the external barrel 13 down to below the core. Therefore they are independent of the upper internal equipments. In some accidental conditions, a nuclear reactor according to the invention is particularly advantageous. One of the most penalizing situation with regard to safety is the loss of coolant due to a rupture in the primary coolant circuit. Internal equipments of a reactor according to the invention will permit the above-described flow shown with white arrows in FIGS. 1 and 2, to enter the core downwardly, even after a rupture of said primary coolant circuit just before the coolant inlet nozzle into the vessel. Relatively cold coolant existing in the separating means and the dead volume 17 under cover 3 via the guide tubes 21 of the drive shafts 11, will directly fill the core in case of accident. The gravitation force and the overpressure which reign at the beginning of an accident in device 22 and volume 17 direct the coolant to the core through cluster guides 23 and lower plate of device 22. Immediately after the accident, the coolant volume having the vessel inlet temperature, and which is available in device 22 and in capacity 17 will provide cooling of the core for a time of the order of 30s, sufficient to allow the medium pressure safety injection pumps 52, MPSI, known in the prior art and forming part of the injection means 40, to start up and to reach their nominal delivery rate. In an advantageous embodiment, but in no way limitative, the MPSI pumps 52 inject the coolant in the lower part of device 22. Two penetrations 53 pierced in the vessel flange and six pipes 41 will distribute the coolant in close proximity of the upper part of the core. To inject coolant at the lower part of device 22 limit heat exchanges between the cold fluid delivered by the MPSI pumps and the fluid at the vessel inlet temperature or the vapor which are contained in device 22 and capacity 17, thus avoiding a pressure drop, which could result in slowing down, even preventing, the flow of safety injection fluid to reach the core for cooling said core. The delivery rate of the MPSI pumps and the coolant passage sections through plate 24 and guiding tubes are determined to maintain a certain level of coolant in device 22, therefore authorizing an equal distribution of the coolant delivered by the MPSI pumps into all the assemblies of the core. It is thus possible to maintain the temperature of the elements of the fuel assemblies at an acceptable level, until the core is again refilled with water at the end of the accident, by means known per se, such as low pressure safety injection pumps (LPSI). External accumulators are no more necessary for reducing the rewatering time and can be avoided. Dimensions of the LPSI pumps may even be reduced. |
description | ||
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052251144 | description | DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS As shown in FIG. 1 of the drawing, the claimed apparatus is a multipurpose container 10 that comprises a polymeric inner container 12 disposed within a concrete outer shell 14. The polymeric inner container 12 is preferably composed of linear polyethylene, i.e., high density polyethylene in which the polyethylene chains are relatively straight and closely aligned. The polymeric inner container 12 has, in general, an inner surface 16 and an outer surface 18. The polymeric inner container has a primary lid, 20, also composed of polymer. The primary lid 20 contains an opening 22. The primary lid 20 is fastened to the polymeric inner container by heat welding, a well-known process. A smaller secondary lid, 24, is used to cover the opening 22. Also contained in the primary lid 20 is a high efficiency particulate filter, or HEPA filter 26, which allows gases to vent into and out of the container, while shutting in radioactive particles. The concrete outer shell 14 also has a lid 28, an inner surface 30, and an outer surface 32. The polymeric inner container 12 is typically manufactured in any of a number of manners, such as by injection molding, or by heat welding individual sheets of polyethylene together. Preferably, however, the polymeric inner container is manufactured by a rotomolding process. The concrete outer shell 14 is typically made through a precasting process, and is metal reinforced. The concrete may be reinforced with epoxy coated wire mesh or reinforcement bar. The concrete may also have various additives admixed into it during the concrete blending procedure. Such additives may include various high range water reducing agents, or pozzolanic materials such as fly ash and silica fume. The concrete may also be a reinforced, for instance, with amorphous metal fibers obtained from SOGEFIBRE of France. Such fibers are generally produced by quenching a liquid metal jet onto a cooled wheel that is rotating at a high speed. The resulting metal fibers are noncrystalline in structure, and thus highly corrosion resistant. Various hooks and lifting pins can be embedded into the concrete outer shell during its casting. For instance, body lift pins 34 can be provided in order to allow the container to be lifted. Lid lift pins 36 can similarly be cast into the lid 28. A pair of forklift notches 38 and 40 are preferably cast into the bottom of the concrete outer shell, into which the forks of a forklift can be inserted in order to allow the container to be safely lifted. Finally, in order to provide protection from radiation, shielding 42 (not shown) can be placed within the container 10, for instance between each outer surface 18 of the inner container 12 and the adjacent inner surface 30 of the outer shell 14. This shielding 42 can be fabricated from steel, iron, lead, high density concrete, or combinations thereof. An alternative embodiment of the claimed apparatus, differing only in that its shape is cylindrical, is shown in FIG. 2. Turning now to FIG. 3, the claimed multipurpose container is seen as it exists during the first stage of the claimed process, the processing and storage stage. Prior to shipment of the multipurpose container to the processing location, various processing devices (not shown) are placed into the inner container 12. These devices may include mixers or filter elements that are used in order to further treat low-level radioactive waste once it is introduced into the container. Such treatment may include mixing the waste within the container while adding chemical conditioners in order to form a stabilized waste form, or suctioning through a filter element in order to evacuate water from the container while leaving the radioactive waste behind. Such treatment devices and procedures are generally known. After the processing devices are positioned inside of the container, the lid 20 is heat welded into place. With this step, the processing devices are essentially sealed into the container, where they remain. The secondary lid 24, however, is not yet sealed into place over the opening 22. At the processing location, a fillhead 44 is placed into the opening 22 in the secondary lid 20. The fillhead 44 is supported by a process lid 45, which rests on the top of the concrete outer shell 14. The fillhead serves several purposes. First, waste material is introduced through the fillhead into the inner container 12. Additives, such as those used to condition the waste for stabilization, may also be added through the fillhead into the inner container. The fillhead also provides the necessary connections to the various processing devices that are located within the inner container 12. For instance, suction lines that run from a dewatering pump into the fillhead are connected at the fillhead onto pipes inside of the inner container, which are in turn connected to the various filter elements. After the waste has been introduced into the container and processed, the fillhead 44 is withdrawn from the opening 22, which is then covered and sealed with the secondary lid 24. The sealing of the lid is typically carried out at the processing location. In order to simplify the attachment of the secondary lid 24 onto the lid 20, a wire, coated with polyethylene, may be positioned around the outer edge of the secondary lid 24. After the secondary lid 24 is positioned in place over the opening 22, the ends of the wire are connected to an electrical current. This causes the wire to heat up, melting the polyethylene coating, and welding the secondary lid 24 onto the lid 20. The waste is now fully sealed within the inner container 12. Turning now to FIG. 4, the lid 28 is now positioned onto the concrete shell 14, resting on a lip 46, also shown in FIG. 1. The lid 28 can be grouted into place at this time by inserting grout into the gap 29 between the lid 28 and the outer shell 14. Alternatively, the lid can be left ungrouted, if it is likely that it will be removed at some future time, for instance if a final inspection of the inner container is to be conducted immediately prior to disposal. The multipurpose container is now in condition to be either stored on site, or to be transported to another location for disposal. Turning now to FIG. 5, a manner of securing the filled multipurpose container 10 onto a flatbed vehicle 48 is shown. The filled container 10 is place onto the bed 50 of the vehicle 48, being held generally in place by a number of chocks 52. A beam 54 is passed through each forklift notch 38 and 40, extending slightly out of the notch. An impact limiter 56 is placed over the top of the container 10, and is held in place by a number of cables 58, each of which passes from the impact limiter to one of the beams 54. A container restraining band 60, preferably made of performed steel, is placed around the multipurpose container, with its ends bolted together tightly. A number of tie-down cables 62 extend from the container restraining band 60 to the bed 50 of the vehicle. The cables 58 and 62 are each provided with a tensioning apparatus 64, such as a ratchet binder. After the filled container has been transported to the disposal site, it is disposed of in any of the known manners. The multipurpose container is appropriate for burial, for storage in warehouses, or for any of a number of other methods for storing or disposing of low-level radioactive waste. In light of the above disclosed process, it is readily apparent that it is not necessary to remove the inner container 12 from the outer concrete shell 14 at any time during the process. Thus, the concrete shell, either alone or in combination with a radiation shield, can be relied upon at all times to provide structural support for the polyethylene inner container. As a result, the inner container can be constructed with thinner walls than would be required if it had to removed from the outer shell at any time. Thus, while a freestanding polyethylene container full of liquid waste would typically have a wall thickness of at least one half inch, the inner container of the present multipurpose container can be as thin as one quarter inch. Furthermore, since there is typically very little gap between the inner container and the outer shell of the multipurpose container, the amount of waste that can be contained within a given stored volume is considerably greater than for a typical container that is placed inside of a concrete overpack prior to disposal, in which a considerable gap is left between the container and overpack. While the preferred embodiments of the claimed method and apparatus have been described, and various alternative embodiments have been suggested, it should be understood that other embodiments could be devised based upon the principles of the claimed method and apparatus of this invention that would remain within the spirit of the invention and the scope of the appended claims. |
053944461 | claims | 1. A gauge for checking that an uncoupling rod of a control rod drive is inserted in a center hole of a spud, comprising a platelike cross handle having a central portion and a plurality of arms extending radially outwardly therefrom, and a first cylindrical ring having one end connected to a bottom surface of said central portion of said cross handle and extending axially downward, said first cylindrical ring having a first axial cylindrical hole of predetermined diameter and said central portion of said cross handle having a second axial cylindrical hole of said predetermined diameter, said first circular cylindrical ring being positioned so that said first and second cylindrical holes have collinear axes. 2. The gauge as defined in claim 1, wherein the number of said arms is four, said arms extending radially outwardly from said central portions at angular intervals of 90.degree.. 3. The gauge as defined in claim 1, further comprising a second cylindrical ring having one end connected to said bottom surface of said central portion of said cross handle and extending axially downward, said second cylindrical ring having an inner diameter greater than an outer diameter of said first cylindrical ring, said first and second cylindrical rings being arranged concentrically with an annular space therebetween. 4. The gauge as defined in claim 3, wherein said annular space has a width such that the fingers of a spud of a control rod drive can be received therein. 5. The gauge as defined in claim 1, wherein said predetermined diameter is greater than the diameter of an uncoupling rod of a control rod drive. 6. A gauge for checking that an uncoupling rod of a control rod drive is inserted in a center hole of a spud, comprising: support means having a planar bottom surface; means for receiving said uncoupling rod having one end connected to said bottom surface of said support means and extending axially downward; and means for centering said uncoupling rod receiving means relative to said center hole of said spud, said centering means being connected to said support means. mounting a gauge having a cylindrical bore of predetermined diameter greater than the diameter of said uncoupling rod at a position so that said cylindrical bore is centered over said center hole; and lowering said index tube until the top end of said installed uncoupling rod is at a predetermined elevation higher than a bottom end of said cylindrical bore, said uncoupling rod being correctly installed if said top end is freely inserted in said cylindrical bore as said index tube lowers. 7. The gauge as defined in claim 6, wherein said support means comprises a platelike cross handle having a central portion and a plurality of arms extending radially outwardly therefrom. 8. The gauge as defined in claim 7, wherein the number of said arms is four, said arms extending radially outwardly from said central portions at angular intervals of 90.degree.. 9. The gauge as defined in claim 7, wherein said uncoupling rod receiving comprises an axial cylindrical hole of predetermined diameter formed in a first cylindrical ring, said first cylindrical ring having one end connected to said bottom surface of said support means and extending axially downward, and said centering means comprises a circular cylindrical outer surface of said first cylindrical ring. 10. The gauge as defined in claim 9, wherein said predetermined diameter is greater than the diameter of said uncoupling rod. 11. The gauge as defined in claim 9, further comprising a second cylindrical ring having one end connected to said bottom surface of said support means and extending axially downward, said second cylindrical ring having an inner diameter greater than an outer diameter of said first cylindrical ring, said first and second cylindrical rings being arranged concentrically with an annular space therebetween. 12. The gauge as defined in claim 11, wherein said annular space has a width such that the fingers of said spud can be received therein. 13. A method for checking that an uncoupling rod of a control rod drive is inserted in a center hole of a spud mounted on an index tube, comprising the steps of: |
abstract | Provided is an X-ray imaging apparatus which includes a collimator configured to adjust an irradiation range of an X-ray irradiated from the X-ray source. The collimator comprises a first field size range adjustor comprising a first plurality of blades and a driving power transfer unit configured to transfer driving power to the first plurality of blades, a second field size range adjustor facing the first field size range adjustor and comprising a first plurality of blades, and a connector configured to respectively connect the first plurality of blades of the first field size range adjustor to the first plurality of blades of the second field size range adjustor so as to make the first plurality of blades of the second field size range adjustor move as the first plurality of blades of the first field size range adjustor move. |
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abstract | A canister for transporting and/or storing radioactive materials, the canister comprising two concentric shells between which is housed a radiological protection device comprising at least a first and a second metal components adjacent along a circumferential direction. According to the invention, the first component is supported against the outer shell and at a distance from the inner shell, whereas the second component is supported against the shell and at a distance from the shell. In addition, the components are in contact with each other along an interface taking, in section along any plane orthogonal to the longitudinal axis and crossing this interface, the form of a straight line segment defining with a radial straight line crossing it at its centre an acute angle (A). |
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abstract | Provided is a technique for X-ray reflection, such as an X-ray reflecting mirror, capable of achieving a high degree of smoothness of a reflecting surface, high focusing (reflecting) performance, stability in a curved surface shape, and a reduction in overall weight. A silicon plate (silicon wafer) is subjected to thermal plastic deformation to form an X-ray reflecting mirror having a reflecting surface with a stable curved surface shape. The silicon wafer can be deformed to any shape by applying a pressure thereto in a hydrogen atmosphere at a high temperature of about 1300° C. The silicon plate may be simultaneously subjected to hydrogen annealing to further reduce roughness of a silicon surface to thereby provide enhanced reflectance. |
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abstract | According to one embodiment of a reactor core monitoring system, includes: an information retention portion for retaining a regular cycle and a short cycle as calculation information of reactor core performance data; a signal processing portion for creating heat balance data based on a process signal; a data acquisition portion for acquiring, in a timing of the regular cycle, the heat balance data and reactor core performance data which was calculated in a previous timing of the regular cycle, while acquiring, in a timing of the short cycle asynchronous to the regular cycle, the heat balance data and reactor core performance data which was calculated most recently; and a data calculation portion for calculating new reactor core performance data based on the acquired reactor core performance data and the heat balance data. |
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054328284 | abstract | The replacement is performed from a repair area located above the convex face (1a) of the head. The adaptor to be replaced is machined, after dismounting its drive mechanism (13) and a thermal sleeve (4), by inserting an appropriate tool (14) via the upper end of the adaptor (3') to be replaced. Machining of the lower portion of the adaptor and of a portion of the weld of this adaptor, the machining of a narrow bevel in the weld of the adaptor to be replaced, reboring of the remaining portion of the adaptor to be replaced (3') inside the head (1), extraction of the adaptor, the installation, by cold shrink-fitting, of a replacement adaptor and the welding of the replacement adaptor are performed in succession. |
description | Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this disclosure and are not admitted to be prior art by inclusion in this section. An x-ray system typically includes an x-ray tube and a detector. The power and signals for the x-ray tube can be provided by a tube generator. The x-ray tube emits radiation, such as x-rays, toward an object. The object is positioned between the x-ray tube and the detector. The radiation typically passes through the object and impinges on the detector. As radiation passes through the object, internal structures of the object cause spatial variances in the radiation received at the detector. The detector then generates data based on the detected radiation, and the system translates the radiation variances into an image, which may be used to evaluate the internal structure of the object, such as a patient in a medical imaging procedure or an inanimate object in an inspection scan. The radiation detector (e.g., x-ray detector) can include a conversion element that converts an incoming radiation beam into electrical signals, which can be used to generate data about the radiation beam, which in turn can be used to characterize an object being inspected (e.g., the patient or inanimate object). In one example, the conversion element includes a scintillator that converts a radiation beam into light, and a sensor that generates electrical signals in response to the light. The detector can also include processing circuitry that processes the electrical signals to generate data about the radiation beam. In some configurations, a collimator can be positioned between the x-ray tube and the object. The collimator can adjustably narrow the radiation beam to a specific area of interest on the object. The technology (devices, systems, and methods) described herein provides collimator solutions to adjust the radiation beam from a radiation source. A collimator is a device that narrows a beam of particles or waves (e.g., x-ray radiation) so the directions of motion becomes more aligned in a specific direction or the spatial cross section of the beam becomes smaller (i.e., a beam limiting device). Collimators used to limit x-ray radiation can have features that include materials (e.g., lead [Pb]) to absorb or block radiation. Collimators can include various structures, shapes, sizes, and mechanisms for different application. Collimators can limit the x-ray beam to a specific region of interest (e.g., examination area or a treatment area) or improve image quality by reducing x-ray scattering. Collimator can be used to reduce exposure of patient tissue from x-ray radiation that is outside the target area, which can be beneficial to the patient by reducing the total x-ray dose to the patient (or operator). Collimators can be used in various applications, such as radiological imaging and therapy, computed tomography (CT), fluoroscopy, and mammography. A collimator can have a drive mechanism that uses ramps and control pins to pivot shutter pairs in a collimator assembly. The use of the drive mechanism can provide a compact design (e.g., in height) of the shutters. In an example, a collimator assembly includes a base and a shutter assembly. The shutter assembly includes a lower shutter and a shutter control. The lower shutter includes a yoke, a control pin, and an inner extension extending from a first end of the yoke and supports the control pin. The shutter control includes a ramp feature that is slidably engaged with the control pin. The yoke rotates or tilts as the control pin slides along the ramp feature and the shutter control is slidably engaged with the base. In another example, the shutter assembly further includes a first shutter bracket attached to the base and a second shutter bracket attached to the base. The lower shutter further includes an outer extension extending from a second end of the yoke, an outer hinge pin supported by the outer extension and the second shutter bracket, and an inner hinge pin supported by the inner extension and the first shutter bracket. The outer hinge pin is hingedly engaged with the outer extension or the second shutter bracket. The inner hinge pin is hingedly engaged with the inner extension or the first shutter bracket. In another configuration, the base includes an opening (i.e., a hole) and the shutter assembly further includes an upper shutter with a lower end that is in communication with the lower shutter. Communication refers to being coupled to, adjacent to, or in close proximity to a component (e.g., lower shutter) through direct contact or attached via another medium (e.g., shutter base). A majority of the upper shutter has a substantially planar shape. The upper shutter rotates or tilts with the rotation of the yoke of the lower shutter and the rotation of the upper shutter is configured to variably block radiation from passing through the opening. The upper shutter can include a circular segment extending from an end of the upper shutter furthest from the lower shutter and the chord of the circular segment is a furthest end of the upper shutter. In another example, the shutter assembly further includes a shutter base coupling the lower shutter to the upper shutter. The lower shutter and the upper shutter can include a radiation shielding material (e.g., lead [Pb]). The shutter assembly further includes a cantilever spring with a first end and a second end. The first end is fixed in position by a middle bracket. The second end applies a resilient force on the upper shutter or a shutter base coupling the lower shutter to the upper shutter. The lower shutter can include a notch in the yoke. The notch in the yoke allows rotation of the lower shutter without applying a direct force on the cantilever spring by the lower shutter. In another configuration, the shutter assembly further includes a second lower shutter. The second lower shutter includes a second yoke, a second control pin, an inner extension extending from a first end of the second yoke and supports the second control pin, a second inner hinge pin supported by the inner extension of the second yoke and the first shutter bracket, an outer extension extending from a second end of the second yoke, and a second outer hinge pin supported by the outer extension of the second yoke and the second shutter bracket. The second inner hinge pin is hingedly engaged with the inner extension of the second yoke or the first shutter bracket. The second outer hinge pin is hingedly engaged with the outer extension of the second yoke or the second shutter bracket. A length of the yoke is substantially parallel to a length of the second yoke. The shutter control further includes a second ramp feature that is slidably engaged with the second control pin. The second yoke rotates or tilts as the second control pin slides along the second ramp feature. The rotation of the yoke is in an opposite direction as the rotation of the second yoke. In another example, the shutter assembly further includes a first upper shutter with a lower end that is in communication with the lower shutter, and a second upper shutter with a lower end that is in communication with the second lower shutter. A majority of the first upper shutter has a substantially planar shape. The first upper shutter rotates or tilts with the rotation of the lower shutter and the rotation of the first upper shutter is configured to variably block radiation from passing through an opening (i.e., hole) in the base. A majority of the second upper shutter has a substantially planar shape. The second upper shutter rotates or tilts with a rotation of the second lower shutter, and the rotation of the second upper shutter is configured to variably block radiation from passing through the opening. The slideable movement of the shutter control changes the distance between an upper end of the first upper shutter and an upper end of the second upper shutter. In another configuration, the lower shutter, the second lower shutter, and the shutter control form a first shutter assembly pair. The collimator assembly further includes a second shutter assembly pair that includes a third lower shutter, a fourth lower shutter, and a second shutter control. The third lower shutter includes a third yoke and a third control pin. The fourth lower shutter that includes a fourth yoke and a fourth control pin. The a second shutter control that includes a third ramp feature that is slidably engaged with the third control pin and a fourth ramp feature that is slidably engaged with the fourth control pin. The second shutter control is slidably engaged with the base. The third yoke rotates or tilts as the third control pin slides along the third ramp feature and the fourth yoke rotates or tilts as the fourth control pin slides along the fourth ramp feature. The rotation of the third yoke is in an opposite direction as the rotation of the fourth yoke. In another example, the length of the lower shutter and the second lower shutter are substantially perpendicular to a length of the third lower shutter and the fourth lower shutter. A length of the shutter control is substantially perpendicular to a length of the second shutter control. The lower shutter, the second lower shutter, the third lower shutter, and the fourth lower shutter form sides of a substantially rectangular shape with overlapping ends. A portion of the lower shutter and the second lower shutter overlap a portion of the third lower shutter and the fourth lower shutter. In another example, the shutter assembly further includes a control guide attached to the base that substantially confines movement of the shutter control to a single axis. The control guide can include an elongated slot and the shutter control can include at least one protrusion slidably engaged in the elongated slot. The at least one protrusion limits movement of the shutter control in the single axis. Another example provides a method of collimating radiation. The method includes the operation of sliding a shutter control that includes a ramp feature along a base of a collimator assembly. The next operation of the method can include sliding a control pin along the ramp feature when the shutter control slides along the base. The method can further include rotating or tilting a yoke of a lower shutter about an axis of an inner hinge pin when the control pin slides along the ramp feature. The yoke includes an inner extension extending from a first end of the yoke that supports the control pin and the inner hinge pin. The yoke also includes an outer extension extending from a second end of the yoke that supports an outer hinge pin. The next operation of the method can variably block radiation based on the rotation of the lower shutter. In a configuration, rotating the yoke of the lower shutter rotates or tilts an upper shutter extending from the lower shutter. The upper shutter includes a radiation shielding material and provides greater variation in blocking radiation than the lower shutter alone. In another example, the method can further include applying a resilient force from the base to the upper shutter via a cantilever spring. The next operation of the method includes forcing the control pin down onto the ramp feature when the resilient force is applied to the upper shutter. In another example, a collimator assembly includes a base including an opening (i.e., a hole), two shutter controls, four shutter brackets, and four shutter assemblies. Each shutter assembly is located on one of four sides of the opening and each shutter assembly includes a lower shutter. The lower shutters includes a yoke, a control pin, an inner hinge pin, an inner extension extending from a first end of the yoke and supports the control pin and the inner hinge pin, an outer hinge pin, and an outer extension extending from a second end of the yoke and supports the outer hinge pin. Two opposing shutter assemblies provide a shutter assembly pair, and one shutter assembly pair is substantially perpendicular to another shutter assembly pair. The control pins of the lower shutters of each shutter assembly pair are slidably engaged with separate ramp features of one of the two shutter controls. Each yoke rotates or tilts as the corresponding control pin slides along the corresponding ramp feature. The inner hinge pins of the lower shutters of each shutter assembly pair are supported by an inner shutter bracket that is one of the four shutter brackets. The outer hinge pins of the lower shutters of each shutter assembly pair are supported by an outer shutter bracket that is one of the four shutter brackets. Each inner hinge pin is hingedly engaged with the inner extension or the inner shutter bracket, and each outer hinge pin is hingedly engaged with the outer extension or the outer shutter bracket. In another configuration, each shutter assembly further includes an upper shutter that is in communication with the lower shutter, wherein the upper shutter rotates or tilts with the rotation of the lower shutter, and the rotation of the upper shutter is configured to variably block radiation from passing through the opening. The summary provided above is illustrative and is not intended to be in any way limiting. In addition to the examples described above, further aspects, features, and advantages of the invention will be made apparent by reference to the drawings, the following detailed description, and the appended claims. Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Numbers provided in flow charts and processes are provided for clarity in illustrating steps and operations and do not necessarily indicate a particular order or sequence. Unless otherwise defined, the term “or” can refer to a choice of alternatives e.g., a disjunction operator, or an exclusive or) or a combination of the alternatives (e.g., a conjunction operator, and/or, a logical or, or a Boolean OR). Disclosed embodiments relate generally to x-ray collimator and, more particularly, to drive mechanism for shutters of a collimator and methods to operate shutters for a collimator. Reference will now be made to the drawings to describe various aspects of example embodiments of the invention. It is to be understood that the drawings are diagrammatic and schematic representations of such example embodiments, and are not limiting of the present invention, nor are they necessarily drawn to scale. FIG. 1 is a block diagram of an example rotary or rotating anode type x-ray tube 100 with a rotatable disc-shaped anode 122. The x-ray tube 100 includes a housing 102 and an x-ray insert 110 within the housing 102. The housing 102 encloses the insert 110. A coolant or air may fill the space or cavity between the housing 102 and the insert 110. A cathode 112 and an anode assembly 120 are positioned within an evacuated enclosure, also referred to as the insert 110. The anode assembly 120 includes the anode 122, a bearing assembly 130, and a rotor 128 mechanically coupled to the bearing assembly 130. The anode 122 is spaced apart from and oppositely disposed to the cathode 112. The anode 122 and cathode 112 are connected in an electrical circuit that allows for the application of a high voltage potential between the anode 122 and the cathode 112. The cathode 112 includes an electron emitter 116 that is connected to an appropriate power source (not shown). As disclosed in FIG. 1, prior to operation of the example x-ray tube 100, the insert 110 is evacuated to create a vacuum. The insert 110 encloses the vacuum. Then, during operation of the example x-ray tube 100, an electrical current is passed through the electron emitter 116 of the cathode 112 to cause electrons “e” to be emitted from the cathode 112 by thermionic emission. The application of a high voltage differential between the anode 122 and the cathode 112 then causes the electrons “e” to accelerate from the cathode electron emitter toward a focal spot on a focal track 124 that is positioned on the anode 122. The focal track 124 may be composed for example of tungsten (W) and rhenium (Re) or other materials having a high atomic (“high Z”) number. As the electrons “e” accelerate, they gain a substantial amount of kinetic energy, and upon striking the rotating focal track 124 some of this kinetic energy is converted into x-rays “x”. The focal track 124 is oriented so that emitted x-rays “x” are visible to an x-ray tube window 104. The x-ray tube window 104 includes an x-ray transmissive material, such as beryllium (Be), so the x-ray's “x” emitted from the focal track 124 pass through the x-ray tube window 104 in order to strike an intended object (not shown) and then the detector to produce an x-ray image (not shown). FIG. 1 illustrates a single window 104 on the housing 102 (e.g., with a glass insert that allows radiation to pass through the glass of the insert). In other examples, a separate window may be included on both the insert 110 (e.g., a metal insert) and the housing 102, or a window may be included on just the insert 110. As the electrons “e” strike the focal track 124, a significant amount of the kinetic energy of the electrons “e” is transferred to the focal track 124 as heat. To reduce the heat at a specific focal spot on the focal track 124, a disc-shaped anode target is rotated at high speeds, typically using an induction motor that includes a rotor 128 and a stator 106. The induction motor is an alternating current (AC) electric motor in which the electric current in the rotor 128 needed to produce torque is obtained by electromagnetic induction from a magnetic field of stator winding. Then, the rotor 128 rotates a hub of the bearing assembly 130 that is mechanically coupled to the anode 122, which rotates the anode 122. In other examples (not shown), the x-ray tube uses a stationary′ track. After the x-rays are emitted from the x-ray tube, the x-rays strike an intended object (e.g., the patent or inanimate object) and then the radiation detector to produce an x-ray image. The radiation detector includes a matrix or array of pixel detector elements. The pixel detector elements (e.g., x-ray detector element or detector element) refer to an element in a matrix or array that converts x-ray photons to electrical charges. A detector element may include a photoconductor material which can convert x-ray photons directly to electrical charges (electron-hole pairs) in a direct detection scheme. Suitable photoconductor material include and are not limited to mercuric iodide (HgI2), lead iodide (PbI2), bismuth iodide (BiI3), cadmium zinc telluride (CdZnTe), or amorphous selenium (a-Se). In some embodiments, a detector element may comprise a scintillator material which converts x-ray photons to light and a photosensitive element coupled to the scintillator material to convert the light to electrical charges (i.e., indirect detection scheme). Suitable scintillator materials include and are not limited to gadolinium oxisulfide (Gd2O2S:Tb), cadmium tungstate (CdWO4), bismuth germinate (Bi4Ge3O12 or BGO), cesium iodide (CsI), or cesium iodide thallium (CsI:Tl)). Suitable photosensitive element may include a photodiode, a photogate, or phototransistors. Other circuitry for pixel detector elements may also be used. The x-ray tube and radiation detector can be components in an imaging system that are located in an x-ray room. FIG. 2 illustrates an imaging or x-ray system 200 that includes an x-ray-tube 220, a tube generator 222 to provide power and signals to the x-ray tube, a collimator 210 to shape the x-ray beam from the x-ray tube, an x-ray tube support 202 to support the x-ray tube and collimator, a radiation or x-ray detector 230 to capture the emitted x-ray, a table 204 to support a patient or object, and a table pedestal 206 to support the table. The x-ray tube or x-ray tube support can include a mechanism to rotate the x-ray tube in both the horizontal and axial direction relative to the x-ray tube support. The collimator can be coupled near the x-ray tube window 104 (FIG. 1). In a fully open position, the collimator can allow a maximum field size 216 of the x-ray beam, which area or size can change based on the distance of the x-ray detector from the x-ray tube. The maximum field size is the largest effective area that radiation can strike for an x-ray tube-collimator combination. Effective area is the area with radiation strong enough that the radiation can be detected by pixel detector elements of an x-ray detector. As illustrated, the maximum field size is smaller than the area of the x-ray detector. In other examples, the maximum field size of the collimator is larger, equal to, or smaller than the x-ray detector. The operation of the collimator can reduce the effective area of the x-ray radiation down to a minimum collimated field size 218. The minimum collimated field size is the effective area of the x-ray radiation with the collimator in a fully closed position. With adjustment to the collimator, the x-ray radiation can have various sizes or shapes (e.g., rectangles) between the maximum field size and the minimum collimated field size. Although the collimator is shown with an x-ray tube, the collimator 210 may also be used with another radiation source. FIG. 3 illustrates a perspective view of the collimator 210 shown in FIG. 2. The collimator 210 include a collimator assembly 300 (i.e., a first collimator assembly) and dials 311 and 321 to adjust shutters of the collimator assembly. The cross control dial 311 adjust the shutters in the cross shutter control assembly 310 (FIGS. 8A-9B), which adjusts the x-ray radiation exposure in a front to back direction, if viewed from the control dials. The long control dial 321 adjust the shutters in the long shutter control assembly 320 (FIGS. 10A-11B), which adjusts the x-ray radiation exposure in a side to side direction, if viewed from the control dials. The collimator may include a light or laser (not shown) that is illuminated through the collimator window 208 (FIG. 14) to help position the x-ray tube and collimator relative to the object, patient, or x-ray detector 230 (FIG. 2). In another example (not shown), the laser may use a different opening from the collimator window. A mirror may be used to center the collimator light with the collimator assembly. The collimator can include components that include metals (e.g., stainless steel or lead), polymers (e.g., plastics and rubber), paints, or other rigid or resilient materials. The collimator assembly 300 provides one set of shutters for the collimator 210. In another example, the collimator may include another set of shutters (i.e., cross shutters 240 and long shutters 242 in a second collimator assembly in FIG. 15) located within a housing of the collimator. The shutters 240 and 242 of the second collimator assembly can include a radiation shielding or absorbing material and provide additional collimating functionality. The dials 311 and 321 can adjust shutters of the first collimator assembly 300 along with the shutters 240 and 242 of the second collimator assembly. FIGS. 4-13B illustrate various views of the collimator assembly 300. FIG. 4 shows a perspective top view of the collimator assembly. The collimator assembly 300 can include a base 302 (collimator base) with an opening, a source alignment flange 306 that can be used to couple the collimator to the x-ray tube (or tube assembly), and shutters to variably block electromagnetic waves (e.g., light and x-ray radiation) passing through the opening. The source alignment flange 306 is shown as a protrusion and a ring. In other examples, the source alignment flange can have another shape that can mate or couple to the x-ray tube. The source alignment flange includes flange lock assemblies 308 that include a flange lock housing 308A, a flange lock 308B, and a set screw 308G. The flange lock 308B adjustably applies a force on a mating feature of the x-ray tube. The adjustment is provided by a set screw 308G. The set screw head can be a hexagonal, slot, Phillips, Torx head, or other type of head that allows a torque to be applied to the screw. The collimator assembly 300 can include four shutter assemblies for the four sides of the opening. Each shutter assembly can include an upper shutter 352, 354, 356, and 358; a lower shutter 332, 334, 336, and 338; and a shutter base 342, 344, 346, and 348 that couples the lower shutter to the upper shutter. Upper refers to a relative position closer to (e.g., in the y-axis) an x-ray source or x-ray tube. Lower refers to a relative position further away from (e.g., in the y-axis) the x-ray source or x-ray tube. The shutter base can have a substantially planar form that follows the form of the upper shutter or lower shutter. Upper and lower can refer to relative positions along a y-axis. The upper shutter can be coupled to one side of the shutter base and the lower shutter can be coupled to another side of the shutter base. The coupling may include screws. In another example (not shown), the upper shutter and lower shutter can be coupled to the same side of the shutter base. FIGS. 4-13B illustrate the upper shutter, lower shutter, and shutter base as three separate components. In another example, the upper shutter, lower shutter, and shutter base may be integrated as one or two components. The upper shutter, lower shutter, or shutter base can include a radiation shielding or absorbing material, such as lead (Pb). As illustrated in FIG. 5, the base (302 of FIG. 4) of the collimator assembly can include a base radiation shield 304 that includes radiation shielding or absorbing material, such as lead (Pb). Thus, the radiation emitted from the x-ray tube can be blocked by the radiation shielding or absorbing material except through the opening of the base and the area not blocked by shutters of the shutter assemblies. FIG. 6 illustrates a perspective bottom view of the collimator assembly 300. The collimator assembly includes two sets of shutters: cross shutters 332, 334, 342, 344, 352, and 354 controlled by a cross shutter control 312 that is moved, driven, or adjusted (e.g., in the x-axis) by the cross control dial 311 (FIG. 3) for front and back adjustment; and long shutters 336, 338, 346, 348, 356, and 358 controlled by a long shutter control 322 that is moved, driven, or adjusted (e.g., in the y-axis) by the long control dial 321 (FIG. 3) for side to side adjustment. In another example (not shown), the cross shutter control and the long shutter control is operated by a motorized mechanism and electronic controls (with or without feedback and sensors). Referring back to FIG. 6, the cross shutter control 312 operates on the cross shutters via the cross lower shutters 332 and 334. The long shutter control 322 operates on the long shutters via the long lower shutters 336 and 338. Cross refers to components associated with or near the cross shutter control 312. Long refers to components associated with or near the long shutter control 322. Each lower shutter includes an inner extension 332A, 334A, 336A, and 338A; an outer extension 332C, 334C, 336C, and 338C; and a yoke 334B, 336B, and 338B that couples the inner extension to the outer extension. Inner refers to a relative position of a component closer to a shutter control (e.g., cross shutter control 312 and long shutter control 322). Outer refers to a relative position of a component farther away from the shutter control. For example, a cross inner lower shutter (CILS) 332 is closer to the long shutter control 322 than a cross outer lower shutter (COLS) 334. A long inner lower shutter (LILS) 336 is closer to the cross shutter control 312 than a long outer lower shutter (LOLS) 338. Similarly, the COLS inner extension 334A is closer to the cross shutter control 312 than the COLS outer extension 334C. From a top or bottom view, the ends (e.g., yoke or extension) of the lower shutter can overlap with the ends of an adjacent lower shutter. For example, the ends of CILS 332 overlaps with ends of LILS 336 and LOLS 338, and the ends of COLS 334 overlaps with the other ends of LILS 336 and LOLS 338. The extensions of the lower shutters support control pins and hinge pins, which is also illustrated in FIG. 7. The inner extension 332A, 334A, 336A, and 338A supports a control pin 362, 364, 366, and 368 and an inner hinge pin 361A, 363A, 365A, and 367A. The outer extension 332C, 334C, 336C, and 338C supports an outer hinge pin 361B, 363B, 365B, and 367B. The lower shutters are hingedly engaged or connected to the base 302 through the hinge pins supported by brackets 382, 384, 386, and 388. For example, the CILS inner hinge pin 361A and the COLS inner hinge pin 363A are supported by the LILS bracket 386, and the CILS outer hinge pin 361B and the COLS outer hinge pin 363B are supported by the LOLS bracket 388. The LILS inner hinge pin 365A and the LOLS inner hinge pin 367A are supported by the CILS bracket 382, and the LILS outer hinge pin 365B and the LOLS outer hinge pin 367B are supported by the COLS bracket 384. The brackets are coupled to the base using screws, bolts, semi-permanent attachment mechanism, or permanent attachment mechanism. A semi-permanent attachment mechanism includes a screw, a bolt, or other mechanism that can be attached or unattached through manipulation of a component of the attachment mechanism. A permanent attachment includes a weld, an adhesive, heat or chemical treatment to combine two component together, which requires more than manipulation of the components to remove the components from each other without damage to the components. Unless otherwise stated, the attachments for the collimator assembly can be provide by the semi-permanent attachment mechanism or the permanent attachment. The bracket 386 and 388 may include a notch (e.g., LILS bracket notch 387 or LOLS bracket notch 389). For example, the LILS bracket 386 includes a LILS bracket notch 387 to allow downward movement of the CILS control pin 362 on a cross control inner ramp 314 (also seen in FIG. 9B). The lower shutters 332, 334, 336, and 338 (e.g., the yoke 334B, 336B, and 338B) rotate or pivot around or about the hinge pins 361A-B, 363A-B, 365A-B, and 367A-B with the inner extensions 332A, 334A, 336A, and 338A along with the control pins 362, 364, 366, and 368 acting as a lever arms. The control pin moves in a nearly vertical (e.g., up and down with a slight angle) based on lateral movement (along the x-axis or the z-axis) of the shutter control 312 and 322 along the base 302. The shutter control can have a substantially rectangular cuboid with various features. Each shutter control 312 and 322 includes at least one ramp feature 314, 315, 324, and 325 (i.e., incline/decline portion or wedge in the shutter control) that is slidably engaged with the control pins. The cross shutter control 312 includes two ramp features (i.e., cross control inner ramp 314 and cross control outer ramp 315) on opposite sides of the shutter control. The cross control inner ramp 314 slidably engages with CILS control pin 362, and the cross control outer ramp 315 slidably engages with COLS control pin 364. The long shutter control 322 includes two ramp features (i.e., long control inner ramp 324 and long control outer ramp 325) on a same side of the shutter control. The long control inner ramp 324 slidably engages with LILS control pin 366, and the long control outer ramp 325 slidably engages with LOLS control pin 368. As the shutter control slides along a single axis (e.g., x-axis or the z-axis), the control pin slides along the ramp and moves the control pin up or down (in the y-axis) a ramp, which in turn rotates or pivots the lower shutter. The lower shutter then rotates or tilts the shutter base 342, 344, 346, and 348 and the upper shutter 352, 354, 356, and 358, which moves opposing upper shutters closer together or farther apart to collimate the radiation (or electromagnetic wave). A large movement of the control pin along the ramp can generate a relatively small rotation of the lower shutter, which can provide a relative small movement of a circular flange segment 352C, 354C, 356C, and 358C of the upper shutter. The slope (or angle) of the ramp can determine the amount (or degree) of rotation or tilt of the lower shutter relative to the linear motion of the shutter control. A length of the lever arm of the inner extension of the lower shutter can also determine the amount (or degree) of rotation or tilt of the lower shutter relative to the linear motion of the shutter control. For example, a steep slope increases the rotation or tilt of the lower shutter with a linear motion to the shutter control compared to a shallow slope. The slope of multiple ramps can be similar to each or differ from each other. For example, the cross shutter control can have ramp slopes that are similar and the long shutter control can have ramp slopes that are similar, but the ramp slopes of the cross shutter control can have different angles from the ramp slopes of the long shutter control. The control pins 362, 364, 366, and 368 can have a cylindrical shape with various diameters in the same control pin. The different diameter can be used various reasons, such as avoiding contact with other components. For example, the LOLS control pin 368 can have a narrow diameter near the long control ramps 324 and 325 to avoid contact with the long control inner ramp 324. As illustrated by FIG. 7, a flat spring or cantilever spring 372, 374, 376, and 378 applies a resilient force on the shutter base 342, 344, 346, and 348 (or upper shutter). A resilient force is a force provided by a resilient or elastic component, such as a spring, which changes as the resilient or elastic component deflects. In an example, the shutter base may allow some deflection of the shutter. One end of the spring can be held or fixed in position by the bracket 382, 384, 386, and 388. The 372 CILS spring is secured by the CILS bracket 382, the COLS spring 374 is secured by the COLS bracket 384, the LILS spring 376 is secured by the LILS bracket 386, and the LOLS spring 378 is secured by the LILS bracket 386. The other end of the spring slides along the shutter base. The resilient force of the spring is translated as a force on the control pin 362, 364, 366, and 368 onto the ramp feature 314, 315, 324, and 325, which can keep the control pin engaged on the ramp features. The yoke 334B, 336B, and 338B of the lower shutter 332, 334, 336, and 338 can include a lower shutter notch 333, 335, 337, and 339 above the lower shutter, as with CILS notch 333 and COLS notch 335, or below or laterally to the lower shutter, as with LILS notch 337 and LOLS notch 339 to allow free movement of the spring without interference from the lower shutter or having the spring touch the lower shutter. The shutter base (e.g., cross inner shutter base [CISB] 342 and cross outer shutter base [COSB] 344) may include a slot or opening for the spring to cross the plane of shutter base from the bracket to an opposite side of the shutter base. Referring back to FIG. 6, each shutter control 312 and 322 is slidably engaged with a control guide or control guide assembly 316 and 326 that is attached (e.g., using screws) to the base 302. In an example, the control guide components or structure 316 and 326 can have similar features. The control guide includes a guide channel (e.g., cross guide channel 317 or long guide channel 327) in the control guide that supports a portion of the shutter control. The guide channel can be a void (i.e., space) in the control guide. The control guide assembly can include a single component or multiple components. FIG. 6 illustrates the control guide assembly as two components that are mirror images of each other (e.g., lower cross control guide 316A and upper cross control guide 316B for the cross shutter control assembly 310; and lower long control guide 326A and upper long control guide 326B for the long shutter control assembly 320). The control guide includes a guide slot (e.g., lower cross guide slot 318 and upper cross guide slot [not shown]; and lower long guide slot 328 and upper long guide slot [not shown]) that slidably engages with control protrusions (e.g., cross control protrusions 313A-D and long control protrusions 323A-D) extending from the shutter control. The control protrusions can extend above a substantial surface or plane of the shutter control and below a substantial surface or plane of the control guide. The guide channel and the control protrusions substantially confine, restrict, or limit the movement of the shutter control to a single axis (e.g., x-axis for the cross shutter control 312 and z-axis for the long shutter control 322). The cross shutter control slides along the cross control guide 316 in the x-axis. The long shutter control slides along the long control guide 326 in the z-axis. The length of the guide slot and the position of the control protrusions can confine, restrict, or limit the distance or movement of the shutter control within the single axis. The control guide and guide channel interfaces with one edge of the shutter control (opposite to the edge or side with the ramp features), which can reduce tilting, lifting, twisting, or torque of the shutter control. Another guide on the opposite edge of the shutter control (on the same edge or side with the ramp features), such as a long anti-tilting block or bracket 329, can provide additional stability against tilting, lifting, twisting, or torque of the shutter control. The long anti-tilting block 329 can hold the long shutter control 322 in a substantially parallel position relative to the base or control guide when the LILS control pin 366 and LOLS control pin 368 apply a force on the long control ramps 324 and 325. The cross shutter control 312 may also include a cross shutter control notch 309 that can receive a cross collimator guide 212 (FIG. 14) that couples the cross shutter control to the cross control dial 311 via a geared mechanism. The long shutter control 322 may also include a long shutter control notch 319 that can receive a long collimator guide 214 (FIG. 14) that couples the long shutter control to the long control dial 321 via another geared mechanism. FIGS. 8A-9B illustrate various views of cross shutters (including a cross inner upper shutter [CIUS] 352 and a cross outer upper shutter [COUS] 354) relative to the cross shutter control 312 in open and closed positions. FIGS. 10A-11B illustrate various views of long shutters (including a long inner upper shutter [LIUS] 356 and a long outer upper shutter [LOUS] 358) and the long shutter control 322 in open and closed positions. FIGS. 12A-B illustrate perspective bottom views of the collimator assembly in open and closed positions. FIGS. 13A-B illustrate perspective top views of the collimator assembly in open and closed positions. As shown in FIGS. 8A-8B and 10A-10B, the upper shutter can have substantially folded planar shape (or folded plate) of an “I” with one elongated flange (or substantially planar flange segment 352A, 354A, 356A, and 358A) and another circular segment flange (or circular flange segment 3520, 354C, 356C, and 358C) with a web 352B and 358B joining the elongate flange with the circular segment flange. A void between the planar flange segment and the circular flange segment can be referred to as the web notch 353 and 359A. The web and web notch can facilitate overlapping circular segment flanges in adjacent shutters (upper shutters and shutter base) when the shutters are in a closed position. For example, the LIUS circular flange segment 586C and the LOUS circular flange segment 358C can be on the same plane in the vertical (y-axis) as the CIUS web 352B. CIUS web notch 353, COUS web, and COUS web notch, as shown in FIG. 13B. The circular flange segment may also include a circular segment notch 359B to accommodate the web of an adjacent shutter in a closed position. For example, the LOUS circular segment notch 359A and LIUS circular segment notch can be notched (e.g., substantially rectangular cuboid void) to accommodate the CIUS web 352B and COUS web in a closed position, as shown in FIG. 13B. The planar surface of the circular flange segment can be at angle between 60° and 120° angle with the planar flange segment, as shown in FIGS. 9A-9B and 11A-11B. In another example, the planar surface of the circular flange segment can be at angle between 70° and 110° angle with the planar flange segment. In another example, the planar surface of the circular flange segment can be at angle between 80° and 100° angle with the planar flange segment. In an example the upper shutter can have a substantially uniform width. Each circular flange segment includes a chord edge 352D, 354D, 356D, and 358D. The CIUS chord edge 352D is substantially parallel to the COUS chord edge 354D from the open position to the closed position. The LIUS chord edge 356D is substantially parallel to the LOUS chord edge 358D from the open position to the closed position. Open refers to a substantially maximum distance between the chord edges of opposite facing upper shutters. Closed refers to a substantially minimum distance between the chord edges of opposite facing upper shutters. The upper shutters can be in multiple positions between the open and closed position. The upper shutters can vary in position between the open and closed position. The opening and closing of the shutters (including the lower shutters, the shutter bases, and the upper shutters) collimates the radiation (or other electromagnetic wave, such as visible light). The chord edges of the upper shutters can define the shape of the collimated area. FIG. 13A illustrates an open collimated area 392 with both the cross and long shutters in a fully open position, which can produce a maximum field size 216 (FIG. 2) of an emitted x-ray beam. FIG. 13B illustrates a closed collimated area 394 with both the cross and long shutters in a fully closed position, which can produce a minimum collimated field size 218 (FIG. 2) of an emitted x-ray beam or visible light. The shutter base can have a similar outline and shape to the upper shutter in the area that overlaps with the upper shutter. The shutter base can include features to support the upper shutter, such as tabs in the web notch 353 and 359A. In an example, the upper shutter can include a radiation shielding or absorbing material and the shutter base includes a non-radiation shielding or absorbing material. In another example, both the upper shutter and shutter base include a radiation shielding or absorbing material. In another example, the upper shutter can have a different shape or outline (as shown in FIGS. 3-15) so long at the cross upper shutters can overlap with the long upper shutters and the upper shutter provide a variable collimated area. As illustrated in FIGS. 8A-9B, the CILS 332 is attached to the CISB 342, which is attached to the CIUS 352, and the COLS 334 is attached to the COSB 344, which is attached to the COUS 354. The sliding movement of the CILS control pin 362 on the cross control inner ramp 314 rotates or tilts the cross inner shutter about the CILS hinge pins 361A-B, which moves the CIUS chord edge 352D toward or away from the COUS chord edge 354D. Similarly, the sliding movement of the COLS control pin 364 on the cross control outer ramp 315 rotates or tilts the cross outer shutter about the COLS hinge pins 363A-B, which moves the COUS chord edge 354D toward or away from the CIUS chord edge 352D. The CIUS chord edge 352D can move toward or away from the COUS chord edge 354D simultaneously with movement of the cross shutter control 312. As illustrated in FIGS. 10A-11B, the LILS 336 is attached to the long inner shutter base (LISB) 346, which is attached to the LIUS 356, and the LOLS 338 is attached to the long outer shutter base (LOSB) 348, which is attached to the LOUS 358. The sliding movement of the LILS control pin 366 on the long control inner ramp 324 rotates or tilts the long inner shutter about the LILS hinge pins 365A-B, which moves the LIUS chord edge 356D toward or away from the LOUS chord edge 358D. Similarly, the sliding movement of the LOLS control pin 368 on the long control outer ramp 325 rotates and tilts the cross outer shutter about the LOLS hinge pins 367A-B, which moves the LOUS chord edge 358D toward or away from the LIUS chord edge 356D. The LIUS chord edge 356D can move toward or away from the LOUS chord edge 358D simultaneously with movement of the long shutter control 322. Adjacent upper shutters can have different heights (in the y-axis) to allow the shutters to overlap with each other. For example, the cross upper shutters 352 and 354 have a greater height than the long upper shutters 356 and 358, as shown in FIG. 13B. FIGS. 14-15 illustrates perspective cross-sectional views of the mechanical features (e.g., gears, belts, and springs) that couples the collimator assembly 300 to the control dials or knobs 311 and 321. The mechanical features shown in FIGS. 14-15 are manually operated. In another example (not shown), the mechanical features are electrically driven. Various mechanism can be used to convert or translate the rotary movement of the control knobs into the linear motion for the shutter controls 312 and 322. FIGS. 2-3 and 14-15 illustrates control dials or knobs to adjust or move the shutter controls 312 and 322. In other examples, the controls for the shutter control can include sliding controls or slide controls (instead of control dials or knobs) or electronic controls to adjust or move the shutter controls 312 and 322 or other control device that allows multiple positions of the control. The flowchart shown in FIG. 16 illustrates a method 400 of collimating radiation. The method includes the step of sliding a shutter control that includes a ramp feature along a base of a collimator assembly, as in step 410. The step of sliding a control pin along the ramp feature when the shutter control slides along the base follows, as in step 420. The next step of the method includes rotating a yoke of a lower shutter about an axis of an inner hinge pin when the control pin slides along the ramp feature, where the yoke includes an inner extension extending from a first end of the yoke that supports the control pin and the inner hinge pin, and the yoke includes an outer extension extending from a second end of the yoke that supports the outer hinge pin, as in step 430. The method further includes the step of variably blocking radiation based on the rotation of the lower shutter, as in step 440. The technology (systems, devices, assemblies, components, and methods) described herein can provide a collimator drive mechanism that includes a ramp with a specified slope or angle, which can be used to pivot a control pin up and down, where the control pin is coupled to a spring-loaded top shutter. The relatively long path of the control pin of the lower shutter on the ramp can be transformed to a small movement for the top shutter without using gears or similar mechanism in the collimator assembly. The collimator assembly allows simultaneous movement of the shutter pairs (including the upper shutter along with the lower shutter). The collimator assembly has a very compact design and profile, such as the height of the shutters, which provides a relatively small end product. Reference throughout this specification to an “example” or an “embodiment” means that a particular feature, structure, or characteristic described in connection with the example is included in at least one embodiment of the invention. Thus, appearances of the words an “example” or an “embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the described features, structures, or characteristics may be combined in a suitable manner in one or more embodiments. In the following description, numerous specific details are provided (e.g., examples of layouts and designs) to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, layouts, etc. In other instances, well-known structures, components, or operations are not shown or described in detail to avoid obscuring aspects of the invention. While the forgoing examples are illustrative of the principles of the invention in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention. Accordingly, it is not intended that the invention be limited. Various features and advantages of the invention are set forth in the following claims. |
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045284547 | abstract | A container for the storage and transportation of radioactive material comprising an elongated vessel adapted to receive the material and having a wall thickness and composition attenuating radioactive transmission therefrom, the vessel has an open end formed with an annular thickened portion defining a mouth communicating with the interior of the vessel; a radiation-shielding cover received in the mouth and having a plug-forming portion juxtaposed with a complimentary seat-forming portion of the vessel at the mouth, and a flange extending outwardly from the plug-forming portion, the vessel is provided with a wall bore communicating at one end with the interior of the vessel and terminating at its opposite end within the outline of the radiation-shielding cover, the radiation-shielding cover is provided with a connecting bore registering with the wall bore; an obturating element received in the connecting bore and adapted to block the wall bore; and a further cover secured directly to the vessel outwardly of the radiation-shielding cover and overlying the wall bore and the radiation-shielding cover. |
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043953808 | abstract | A method for the remote testing of spray nozzles on headers in a nuclear reactor containment building to determine whether the nozzles are open or blocked. Heated air under pressure is supplied to the headers, and an open nozzle reaches a higher temperature than a blocked nozzle. The headers and nozzles are scanned by an infrared camera having a thermogram display, and open nozzles appear in the thermogram as extending from the headers whereas blocked nozzles appear as minor protrusions on the headers. The camera is mounted on a polar crane within the building, the crane having an axis of rotation which coincides with the axes of the headers and the camera being displaced from the crane axis, and the crane is rotated around its axis during the scanning of the headers and nozzles by the camera. |
048636819 | claims | 1. In an elongated replacement rod for use with fuel assemblies of the type having two end fittings connected by guide tubes with a plurality of rod and guide tube cell defining spacer grids containing rod support features and mixing vanes, said grids secured to said guide tubes in register between said end fittings at spaced intervals and said fuel rod comprising: an asymmetrically beveled tip; a shank portion having a straight centerline; and a permanently diverging portion between said tip and said shank portion. a shank portion; an asymmetrically beveled tip; said tip having a chamfer which is greater in the direction of the cell interior than are the rod support features and said chamfer being located on said tip opposite to an elongated curved surface portion thereof which extends a greater longitudinal distance toward the shank portion than does the chamfer. 2. The rod of claim 1 in which the permanently diverging portion has a centerline which diverges from the shank portion centerline to locate the end of the diverging portion adjacent the tip out of alignment with the shank portion by an amount greater than the rod separation within said fuel assembly. 3. The rod of claim 2 in which the permanently diverging portion has a centerline which diverges from the shank portion centerline to locate the end of the diverging portion adjacent the tip out of alignment with the shank portion by an amount less than an amount which permits the rod to be improperly guided into a grid cell location out of register with a shank containing grid cell. 4. The rod of claim 1 in which the asymmetrically beveled tip includes a chamfer and an elongated curved surface. 5. The rod of claim 1 in which the asymmetrically beveled tip includes an elongated curved surface portion. 6. The rod of claim 5 in which the permanently diverging portion has a centerline and the elongated curved portion has an intersecting centerline titled with respect to the centerline of the diverging portion. 7. The rod of claim 5 in which the asymmetrically beveled tip includes a chamfer opposite to the elongated curved surface portion. 8. The rod of claim 7 in which the asymmetrically beveled tip chamfer is greater in distance in the direction of the cell interior than are the rod support features. 9. The rod of claim 1 in which the permanently diverging portion is a bowed portion. 10. The rod of claim 1 in which the permanently diverging portion has a length approximately equal to the distance between two adjacent spaced grids of a fuel assembly. 11. The rod of claim 6 in which the permanently diverging centerline and the elongated curved portion centerline define a plane of symmetry of the elongated curved portion. 12. In an elongated replacement rod for use with fuel assemblies of the type having two end fittings connected by guide tubes with a plurality of rod and guide tube cell defining spacer grids with rod support features and mixing vanes, said grids secured to said guide tubes in register between said end fittings at spaced intervals, said rod comprising: |
claims | 1. A method for producing a carbon nanotube collimator comprising the steps of:providing a fiber coated carbon nanotube on a substrate;detaching the carbon nanotube from the substrate to produce a CNT collimator;moving the detached CNT collimator to a transmission electron microscopy grid using a micro-manipulator;attaching the CNT collimator to the transmission electron microscopy grid;using a low ion beam current to thin the CNT collimator to a predetermined CNT collimator channel length; andusing the low ion beam current to clean a surface of the CNT collimator, wherein the CNT collimator is used for applications where a narrow, well-collimated beam of charged particles is required. 2. The method of claim 1, wherein the fiber coated carbon nanotube sample provision step comprises the step of:identifying a fiber having a carbon nanotube core on the substrate; andusing focused ion beam induced chemical vapor disposition to deposit a platinum metal on the fiber coated carbon nanotube to stabilize the fiber coated carbon nanotube. 3. The method of claim 2, wherein the CNT collimator detachment step comprises the steps of:partially detaching the metal coated fiber coated carbon nanotube from the substrate;attaching a micro-manipulator needle to the metal coated fiber coated carbon nanotube; anddetaching the metal coated fiber coated carbon nanotube from the substrate to produce the CNT collimator. 4. The method of claim 3, wherein the step of attaching comprises the step of:moving the detached CNT collimator to a transmission electron microscopy grid using a micro-manipulator;aligning a normal direction of the transmission electron microscopy grid with the CNT collimator;depositing a metal to secure the CNT collimator on the transmission electron microscopy grid; anddetaching the a micro-manipulator needle from the CNT collimator. 5. The method of claim 1, further comprising the step of:using the carbon nanotube collimator for nano-aperture for single ion implementation. 6. The method of claim 1, further comprising the step of:using the CNT collimator for single ion implantation for quantum computers. 7. The method of claim 1, further comprising the step of:using the CNT collimator for high-energy physics including e−-e+ collision and p−-p+ collision. 8. The method of claim 1, further comprising the step of:using the CNT collimator for rapid, reliable testing of the transmission of CNT arrays for transport of molecules. 9. The method of claim 1, further comprising the step of:measuring electron channeling of the CNT collimator. 10. The method of claim 9, wherein the measurement step comprises the steps of:transferring the CNT collimator to a measuring device, wherein the CNT collimator is attached to the transmission electron microscopy grid;setting an electron energy on the measuring device; andobserving channeling of electrons through CNT under TEM observation. 11. The method of claim 10, wherein the electron energy is set at 300 keV, an electron beam is unfocused with a divergence of approximately 1 mrad and a beam spot size is within a range of approximately 3 μm to approximately 4 μm. 12. The method of claim 10, further comprising the step of:tilting the CNT collimator approximately 5% from the aligned direction to view a hollow core of the CNT under transmission electron microscopy. 13. The method of claim 10, further comprising the step of:tilting the CNT collimator approximately one degree to reduce an intensity of a of transmitted electrons and produce a beam having a triangular profile. |
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054266866 | description | DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention contemplates the production of x-rays in a high vacuum by (i) illuminating a photoemissive photocathode with high intensity laser light to cause the emission of copious electrons by the photoelectric effect, (ii) accelerating, and preferably focusing, the emitted electrons in and by a high voltage electric field established between the photocathode and an anode so as to form an electron beam, and (iii) striking the anode, which also serves as an electron beam target, with the accelerated (and focused) electron beam in order to produce x-ray radiation. The present invention further contemplates the production of time-resolved x-rays, including nanosecond and shorter duration x-ray pulses. In order to do so multiple independent and separable techniques are employed. First, the laser is cycled in operation so as to produce time-resolved light pulses, typically 20 picosecond light pulses at a repetition rate of 20 Hz. Alternatively, a laser producing 80 picosecond duration light pulses may be cycled at an 82 Mhz rate, giving an approximate 0.66% duty cycle. Typically pulses of an intermediate duration, nominally 10 picoseconds, are produced at an intermediate frequency, nominally 1 kHz. Second, the electrons periodically emitted from the photocathode in response to the periodic laser light pulses are preferably accumulated in a spatial region near the photocathode--overcoming the normal dispersion of these electrons throughout the region between the photocathode and the anode which would be expected due to the space charge effect--by use of a grid electrode that is positioned between the photocathode and the anode. The grid electrode, typically biased at about 3 kV, functions to accumulate the emitted electrons in bunches. However, it so functions only upon, and during such times, that the much greater high voltage between the photocathode and the anode is switched off. In accordance with an important third aspect of the present invention, the high voltage, typically approximately 100 Kv, between the photocathode and the anode is preferably switched on and off, preferably in a semiconductor switch that is responsive to the laser light pulses. The high voltage is switched on for a time period that spans the period of photoemission, and which is typically substantially coincident with the period of photoemission. The use of a grid electrode, and the switching of the high voltage, are both optional: it is sufficient to create time-resolved x-rays only that the laser should be pulsed. However, use of the grid electrode and switching of the high voltage helps to keel) the emitted electrons tightly grouped in "packets". When these electron packets ultimately strike the anode then the resulting time-resolved x-ray pulse is not appreciably longer than the laser light pulse. In the preferred time-resolved x-ray source in accordance with the present invention each of the activities of (i) photoemission, (ii) accumulation of photoemitted electrons, and (iii) switching of the high voltage is appropriately temporally sequenced and phased. Each laser light pulse (i) photoemissively generates abundant electrons which are (ii) accumulated in a narrow spatial region between the photocathode and anode and then, the high voltage being switched on, (iii) accelerated and focused into a short-duration time-resolved electron beam. The short-duration electron beam is typically equally as short as the laser light pulse from which it arose, or approximately 20 picoseconds in duration. It strikes the anode x-ray target in a tightly focused spot, typically of less than 0.5 mm diameter, producing an x-ray pulse of approximately 20 picoseconds duration and approximately 4-50 millijoules energy. The picosecond x-ray pulse itself may be further gated, such as by having its leading or trailing edges truncated by passage through the x-ray transparent apertures of a rapidly rotating apertured plate. The energy of the time-resolved x-ray pulses is a function of the high voltage, and is typically controlled to be of K, L, or M bands. Normally a high voltage of 100 KV is used to produce K band x-ray pulses. The intensity of the x-ray pulses is a function of (i) the intensity and duration of the laser light pulses, (ii) the efficiency of the photocathode, and (iii) the quantity of electrons that are accumulated between the grid electrode and the photocathode before being accelerated as a packet to the anode. X-ray pulses more intense than 4-10 microjoules, shorter than 20 picoseconds, and/or at duty cycles greater than 0.66% are possible. The time-resolved x-ray source in accordance with the present invention is beneficially operated at pulsed x-ray energies, intensities, and duty cycles that do not require external cooling of the source. Particularly when the source used for photolithography then a photoresist is normally exposed to many individual x-ray pulses. Because of the reasonable energy within each of these pulses (roughly equivalent to a flashed synchrotron radiation x-ray source, the brightest previously known source), the total elapsed chronological and cumulative exposure times are reasonable in support of manufacturing production of semiconductors. In use of the x-ray source in accordance with the present invention for x-ray spectroscopy, the picosecond x-ray pulses are preferably directed to illuminate with x-ray light a scattering sample that is excited in its energy state by the selfsame laser light pulses, appropriately time phased, that originally gave rise to the x-ray pulse. X-ray spectroscopy is thus promoted not only by the low cost and compact availability of x-ray pulses that are sufficiently short and sufficiently intense so as to permit observation by x-ray diffraction of the successive stages of time-variant molecular reactions, but is also promoted by a capability of synchronization of these reactions to the very x-ray pulses that permit the reactions to be observed in the first place. (It can alternatively be considered that the x-ray pulses are synchronized to the reactions.) An x-ray source in accordance with the present invention has utility based on its (i) ability to produce time-resolved x-rays from continuous to picosecond and shorter duration, (ii) excellent focus providing an x-ray emission spot size that is typically less than 0.5 mm in diameter, (iii) ability to use different wavelengths of laser light that result in differing quantities of emitted electrons and intensities of resultant x-rays, including x-rays of microjoule intensities in picosecond intervals, (iv) capability to operate with over a range of high voltages in order to produce x-rays in the K, L, and M bands, (v) substantial lack of heat build-up when operated at a low duty cycle, (vi) compact, desk-top, size and (vii) general reliability and low cost. A preferred embodiment of a time-resolved x-ray source in accordance with the present invention for producing picosecond duration K band x-ray pulses is diagrammatically illustrated in operational use for x-ray spectroscopy in FIG. 1. A scattering sample 2 is illuminated with ultrashort time-resolved x-ray pulses 10, typically of 20 to 50 picoseconds duration, to produce an x-ray image on an x-ray imaging device 3. The x-ray imaging device 3 is typically a photographic plate, or image intensifier, positioned in the Laue backscattering configuration. A goniometer (not shown), or other instrument for measuring angles, helps to align the position of scattering sample 2 with the x-ray beam 10 and with the x-ray imaging device 3. The production of time-resolved x-rays 10 in x-ray source 1 commences with a laser beam 20 that is generated in a pulsed laser 21. The laser 21 is typically of the Nd-YAG type. One such type laser is Spectrophysics Model 3000 YAG laser. It is capable of producing 80 picosecond duration laser pulses at a repetition rate of up to 82 Mhz. A preferred pulsed laser 21 available from Quantel International is capable of producing up to 20 picosecond duration laser light pulses at a repetition rate of 20 Hz. Each laser pulse is of green light (approximately 5320 .ANG.), and contains about 4 millijoules energy. The nominal 10 ps pulses (and even more commonly 6 ps pulses) at the nominal 1 kHz repetition rate (and even more commonly at any repetition rate from 300 Hz to 1 kHz) may be produced at, for example, a 193 nm wavelength with, for example, a commercially-available ArF excimer laser. The laser light pulses 20 produced by pulsed laser 21 are split in first beamsplitter 30 into pulsed laser light beam lines 22, 23. The intensity of the laser light within each such beam line 22, 23 is not necessarily equal in accordance with the transmission, versus the reflection, characteristics of beamsplitter 30. Normally, and in accordance with the requirement for light power in each of the beam lines 22, 23, about 10% of the light 20 goes into beam line 22 and about 90% goes into beam line 23. The laser light pulses within beam line 22 are reflected at mirror 31 and again in prism 32 to impinge upon second beamsplitter 33. The prism 32 may be moved a variable distance, VD.sub.1, from both mirror 31 and beamsplitter 33 in order to induce a variable delay in the time of arrival of the laser light pulses at beamsplitter 33 and at subsequent points. The beam line 22 is split by second beamsplitter 33 into beam lines 24 and 25. As with the beamsplitting performed by first beamsplitter 30, the light energy within each of beam lines 24, 25 need not be equal in accordance with the reflectivity, and transmission, characteristics of beamsplitter 33. Normally almost all of the light within beam line 22, about 99%, goes into beam line 24 and the remainder of the light, about 1%, goes into beam line 25. The laser light pulses in beam line 24 are transmitted through light transparent window 41 of high-vacuum assembly 40 to illuminate photocathode 42. The window 41 is normally clear optical quartz. The high-vacuum assembly 40 maintains photocathode 42, and anode 43, in a high-vacuum, at least less than 10.sup.-6 torr and typically about 10.sup.-9 to about 10.sup.-10 torr. One such high-vacuum assembly suitable to contain the preferred configuration, and spacing, of photocathode 42 and anode 43 (discussed hereinafter) is manufactured by Huntington Mechanical Laboratories, 1400 Stierlin Road, Mountainview, Calif. 94043. Other high-vacuum chambers of other manufacturers are equally suitably adaptable to the purposes of the present invention. The photocathode 42 and anode 43 each have a preferred configuration, a preferred separation, and are each preferably constructed of certain materials. The configuration and separation of the photocathode 42 and anode 43 is a function of the desired shaping of the electron beam between such photocathode 42 and anode 43, and the magnitude of the high voltage that exists between such photocathode 42 and anode 43. One preferred program for the calculation of the geometries, and separations, of both photocathode 42 and anode 43 is available from Stanford University as SLAC Electron Optics Program Vector POT./PLOTFILE version of July 1979. That computer program is directed to the calculation of the contours of a spherical anode that is used within an electron gun. It is publicly available from the Linear Accelerator program of Stanford University. A preferred configuration and separation calculated by the SLAC Electron Optics Program for the photocathode 42 and anode 43 is shown in cross-sectional plan view in FIG. 2. The grid electrode 44 and the focusing plates 45 are also shown. Each of the photocathode 42, anode 43, grid electrode 44 and focusing plates 45 exhibit substantial circular and radial symmetry about an imaginary line of focus 50. The only substantial deviation from circular and radial symmetry is evidenced by the small front surface, oriented in the direction toward photocathode 42, of anode 43. That planar surface is typically angled at 45.degree. relative to line of focus 50 and relative to x-ray pulses 10 (to be discussed), as is best shown in FIG. 1. The distance X, or diameter of the photocathode, is typically about 1.75 centimeters (0.69 inches). The grid electrode 44, preferably in the shape of an annular ring having the indicated cross section and located in a position surrounding the photocathode 42, has a diameter Y of approximately 5.08 centimeters (2 inches). Its central aperture is approximately 1.78 centimeters (0.7 inches) in diameter, which is sufficient to tightly accommodate the 1.75 centimeter (0.69 inch) diameter of photocathode 42. The front surface of anode 43, which is typically about 0.254 centimeters (0.1 inches) in diameter, is nominally located at distance Z = about 1.65 centimeters (0.65 inches) from the surface of photocathode 42. The major diameter of anode 43 is approximately 0.89 centimeters (0.35 inches). The one or more focusing plates 45, which are normally of spheroidal contour with a central aperture, are located approximately half way between cathode 42 and anode 43, or about 0.82 centimeters (0.32 inches) from either. The focusing plates 45 are typically of hemispherical contour. The configurations, and separations, of photocathode 42, anode 43, and focusing plates 45 is directed to sharply focusing an electron beam to a minimum size point on the surface of anode 43 when an approximate 100 kilovolts electrical potential is applied between anode 43 and photocathode 42. In accordance with the present invention, the material of photocathode 42 is improved over a similarly-employed photocathode reported in the article "Practical laser-activated photoemissive electron source" by Lee, et al., appearing in Rev. Sci. Instrum., Vol. 56, No. 4: pp. 560-562 (April 1985). Lee, et al. describe a cesium antimonide (Cs.sub.3 Sb) photocathode that is alleged to be an improvement on previous gallium arsenide (GaAs) and bialkali photocathode materials. In accordance with the present invention metal is added to a semiconductor material by mixing or, preferably, by depositing through sputtering or by annealing. The metal is preferably tantalum (Ta), copper (Cu), silver (Ag), aluminum (Al) or gold (Au), or oxides or halides of these metals (where possible). The semiconductor is preferably cesium (Cs), cesium antimonide (Cs.sub.3 Sb) or gallium arsenide (GaAs). A preferred cathode is constructed from tantalum (Ta) annealed on the surface of nickel. Such a cathode exhibits excellent efficiency in the production of electrons by the photoelectric effect in response to incident green light (.lambda..apprxeq.193 nm), and exhibits many times, approximately four times (.times.4), the fifty (50) hour service lifetime reported by Lee, et al. The anode 43 is preferably made of zirconium (Zr) copper (Cu) or molybdenum (Mo), but other known materials for producing x-ray radiation when bombarded with high-energy electrons are also suitable. Returning to FIG. 1, a high voltage electrical potential is provided between anode 43 and photocathode 42 by high voltage power supply 60. The high voltage of power supply 60 is typically 100 Kv. However, it will be understood that for the purposes of the present invention "high voltage" is any accelerating potential that is suitable for speeding up the electrons in a beam of a cathode ray tube. In accordance with the principles of the invention for the production of time-resolved x-ray pulses, the nominal 100 Kv voltage of high voltage power supply 60 is not necessarily continually applied between photocathode 42 and anode 43. Rather, such high voltage may be gated in the circuit including photocathode 42 and anode 43 by action of semiconductor switch device 70. It is not required in order to produce time-resolved x-ray pulses that the high voltage power supply 60 should be gated by semiconductor switch device 70. It is sufficient only that the laser light, and the resulting photoemission of electrons should be pulsed. Moreover, it is not a trivial matter to switch 100 Kv in a few picoseconds, and undesirable arcing may occur between photocathode 42 and anode 43 if the vacuum is not 10.sup.-9 torr or less. The reason that the high voltage is desirably switched, despite the care that must be given to this procedure, is to better permit the close spatial proximity of photocathode 42 and anode 43, and the effective acceleration of the emitted electrons in bunches, or packets, i.e., in pulses. Particularly if photocathode 42 and anode 43 are at great separation (undesirably allowing the electrons to disperse during their flight from the photocathode to the anode), it will be recognized by a practitioner of electron gun design that it may not be necessary or worthwhile to switch the high voltage. The semiconductor switch device 70 is preferably made from heavily P.sup.+ doped silicon. It is typically about 0.1 mm depth.times.about 3 mm width.times.about 5 mm length. It may be particularly constructed from a LiTaO.sub.3 crystal doped with 2.24% Cu as taught in the article OPTICAL GENERATION OF INTENSE PICOSECOND ELECTRICAL PULSES by Auston, et al. appearing in Appl. Phys. Lett. Volume 20, No. 10: pp. 398-399 (15 May 1972). The copper (Cu) impurities have a strong absorption at 1.06 .mu.m. The beam line 25 of laser light pulses from laser 21 is reflected in two mirrors 34, which may be jointly located at a variable distance VD.sub.3 from beamsplitter 33 and from semiconductor switch 70, so as to impinge upon semiconductor switch 70. A prism may alternatively be used in substitution for the two mirrors 34. Each laser light pulse striking the semiconductor switch 70 generates a macroscopic polarization in such switch resultant from the difference in dipole moment between the ground and excited states of the absorbing Cu.sup.++ impurities. The semiconductor switch 70 will be turned on, conducting the nominal 100 Kv high voltage from power supply 60 to be applied between photocathode 42 and anode 43, during the duration of each laser pulse (nominally 20-50 psec in duration). At other times the semiconductor switch 70 will be turned off and the high voltage from high voltage power supply 60 will not be applied between photocathode 42 and anode 43. The switching action of the preferred semiconductor switch 70 is exceptionally fast, on the order of 2 psec or less. Because lasers can produce light pulses of femtoseconds duration, and because the switching time of the laser-light-activated semiconductor switch that switches the high voltage is on the order of a few picoseconds or less, the principles of the present invention are applicable to producing x-ray pulses of even shorter than 20 picoseconds duration. The shape and separation of the photocathode and the anode must, however, be precisely controlled in order to prevent electron beam dispersion, and resultant lengthening of the x-ray pulses. It is not essential that a laser-light-activated semiconductor switch be used to switch the application of the high voltage supplied by high voltage power supply 60 between the photocathode 42 and anode 43. For example, a magnetron may alternatively be used. Such a magnetron would normally be triggered in its switching action by an electrical circuit that is sensitive to the laser light pulses on beam line 25. Such circuits, and magnetrons, are commonly understood but are deemed less suitable, and slower, than the preferred semiconductor switch. If a magnetron is used, it may be considered to occupy the location in FIG. 1 that is identified by numeral 70. Continuing in FIG. 1, a grid electrode 44 voltage biased by intermediate voltage power supply 61 may be used to improve the bunching of electrons emitted from photocathode 42. As may best be observed in FIG. 2, the grid electrode 44 is positioned surrounding the photocathode 42. The focusing electrode(s) 45 are typically spaced at a separation of 0.82 centimeters (0.32 inches) from each of the photocathode 42 and anode 43. The grid electrode 44 is negatively biased relative to photocathode 42 by first intermediate voltage power supply 61, nominally 3 Kv. The focusing plates 45 are biased relative to photocathode 42 by second intermediate voltage power supply 62, nominally also 3 Kv. Both the first intermediate voltage power supply 61 and the second intermediate voltage power supply 62 may exhibit a range of voltages, typically 2-8 Kv. It is normally preferred that the voltage of second intermediate voltage power supply 62, and the voltage on focusing plates 45, should be equal to or greater than the voltage of first intermediate voltage power supply 61, and the voltage on grid electrode 44. It may be noted that the voltage bias, and the electric field within the vacuum assembly 40, that is created by the first intermediate voltage power supply 61 is of an opposite polarity to the voltage, and electric field, created by the high voltage power supply 60. The first intermediate voltage power supply 61 could optionally be switched off, such as by an oppositely phased counterpart switch to semiconductor switch 70, at the same time that high voltage power supply 60 is switched on. However, this additional switching is not necessary because the electric field created by first intermediate voltage power supply 61 is insignificant in comparison to the electric field created by high voltage power supply 60. Certain additional structure is usefully attached to high vacuum assembly 40 in order to support the renewal of photocathode 42. The photocathode 42, preferably made of tantalum-surfaced cesium antimonide (Ta on Cs.sub.3 Sb), is subject to having its surface ablated by the high intensity laser light impingent upon it from beam line 24. It periodically needs renewal, typically after greater than 200 hours of use at a higher, 0.66%, duty cycle. In order to do so, an x-ray tube isolation valve 130 is opened. The photocathode 42 is withdrawn into the area under deposition monitoring view port 81 by use of a rotary-translation feedthrough, or transfer device, 82. The distal, or operative, end of rotary translation feedthrough device 82 comprises a cathode holder 83. This cathode holder 83 is moved in position while the x-ray tube isolation valve 80 is open so as to engage photocathode 42 and move it to position under deposition monitoring view port 81. At a later time the cathode holder 83, and the rotary-translation feedthrough device 82, is used to restore photocathode 42 to its normal, operative, position as illustrated. When the photocathode 42 is positioned under the deposition monitoring view port 81 it is supplied with fresh cesium from cesium dispenser 84 and with fresh antimony from antimony dispenser 85. This deposition is normally performed by sputtering in a high vacuum. At the conclusion of the deposition the surface of photocathode 42 is substantially renewed, and the photocathode 42 may be redeployed for a further period of producing copious electrons by the photoelectric effect. By a slightly differing mechanical arrangement (as illustrated) two cathodes may be employed, with one in use while the other is being resurfaced or held in reserve. The rapidity of cathode renewal and substitution is generally of greater importance when the x-ray source 1 is used in a production, as opposed to a research, environment. The x-ray pulses 10 that are produced at anode 43 exit the high-vacuum assembly 40 through an x-ray transparent window 46 that is typically made of beryllium (Be). The x-ray pulses 10 may optionally be gated in their path to scattering sample 2 by an x-ray gating device 90. Such a device may be, for example, an apertured plate, or disk, 91 that is driven by a motor 92. The apertured disk 91 is made of a material that is substantially opaque to x-rays, for example lead (Pb). The apertures are transparent to x-rays. The normal rotational speed of apertured disk 91, which is typically several hundred revolutions per minute, is normally not sufficient so as to gate the passage of an x-ray pulse 10, essentially traveling at the speed of light, between the anode 43 and the scattering sample 2 when such pulse is only 20-50 picoseconds (6-10 millimeters at the speed of light) in length. The gating performed by the apertures within the rotating apertured disk 91 can, however, be phased so that such rotating apertured disk 91 serves to truncate either the beginning, or the end, of a time-resolved x-ray pulse. Additionally, it should be understood that the time-resolved x-ray source 1 in accordance with the present invention need not operate exclusively to produce ultrashort, picosecond duration, x-ray pulses. In the event that the x-ray production is continuous, or is produced in pulses of typically millisecond time duration, the x-ray gating assembly 90 may usefully serve to gate the application of x-ray pulses 10 to scattering sample 2. The preferred material, and thickness, of the rotating apertured disk 91 is dependent, as is well in the art, on the energy level of the x-ray pulses 10 which are intended to be gated. The "opaque" and "transparent" regions of the disk 91 may substantially block or pass the x-rays 10, or may attenuate such x-rays 10 to a variable degree. Normally the optional x-ray gating assembly 90 is not employed, but, if it is employed, it may serve as a useful secondary means of controlling, and gating, both the timing and the intensity application of x-ray radiation to an x-ray target object such as scattering sample 2. In operation of the x-ray source 1 for the production of continuous x-ray radiation, a continuous laser light beam produced by a laser 21 continuously impinges upon a photocathode 42 that is located in a high vacuum in order to cause such photocathode 42 to continuously emit numerous electrons by the photoelectric effect. The emitted electrons are continuously accelerated, and focused, in a continuous high voltage electric field that is produced by high voltage power supply 60, so as to continuously strike anode 43 at a small focal spot, typically 0.5 mm or less in diameter. The resulting x-rays are used to illuminate a scattering sample 2, or other x-ray target. Use of the x-ray source 1 in the production of time-resolved x-rays proceeds equivalently. In this use a pulsed laser 21 produces time-resolved pulses of high intensity laser light. Each such laser light pulse causes the photoemission of electrons from photocathode 42. The emitted electrons are preferably maintained in a spatial region that is proximate to photocathode 42, and separated from anode 43, by use of a negatively-biased grid electrode 44. Upon such time as a cloud of electrons has been accumulated in the region between the photocathode 42 and grid electrode 44 within the high vacuum chamber 40, a laser light pulse turns on the semiconductor switch 70 in order to apply the high voltage from high voltage power supply 60 to photocathode 42 and anode 43. Even though the first intermediate voltage power supply 61 is not normally turned off, the accumulated electrons are accelerated from photocathode 42 through electrode 44 to anode 43 as a tightly focused electron beam, or beam packet. The beam packet of electrons strikes the anode 43, or any other electron target that is substituted in their line of flight, with high energy, producing a pulse of x-ray radiation. This pulse of x-ray radiation, which is optionally gated and/or attenuated by a further x-ray gating means 90, impinges upon the scattering sample 2, or other x-ray target. In accordance with still another aspect of the present invention, the scattering sample 2 is energized, including for the initiation and/or maintenance of a molecular reaction therein, by the same laser light pulses that give rise to the x-ray pulses. This light energization of scattering sample 2 is accomplished by directing the laser light pulses on beam line 23 with mirror 35, prism 36, and mirror 37 to impinge on scattering sample 2. The prism 36 may be moved a variable distance, VD.sub.2, relative to mirrors 35, 37 in order to adjust the time at which laser light pulse line 23 is incident upon scattering sample 2 relative to the time at which x-ray pulses 10 are received at the same scattering sample 2. Due to the relatively slow passage of the electron beam packet between photocathode 42 and anode 43 within high vacuum assembly 40, the time of incidence of the laser pulses on beam line 23 at scattering sample 2 may be readily adjusted to be either earlier than, coincident with, or later than, the time of arrival of the x-ray pulses 10 at the same scattering sample 2. The present invention thus contemplates not only the economical and compact production of ultrashort time-resolved x-ray pulses, but also the convenient initiation and energization of molecular reactions that may usefully be examined with such ultrashort time-resolved x-ray pulses. The x-ray source 1 is aligned. A preferred alignment of time-resolved x-ray source 1 enables the high voltage to be applied between photocathode 42 and anode 43 for the duration of the photoemission from photocathode 42. If the high voltage power supply 60 is not to be switched by device 70, then adjustment of delay VD.sub.3 makes it a simple matter to trigger a photodiode, or other light sensor device, to turn on high voltage power supply 60. This turn on typically transpires about 5 nsec before the arrival of the light pulse at photocathode 42 via beam line 24. In other words, beam line 25 is about 1.5 meter (5 feet) shorter to the point where it is sensed than is beam line 24 to the photocathode 42. The power supply 60 is typically turned off after a predetermined time delay, normally of several microseconds. If the high voltage from high voltage power supply 60 is to be switched by semiconductor switch device 70 to photocathode 42 and anode 43 simultaneously that the laser light pulse arrives at photocathode 42 via beam line 24, then a more exacting alignment of x-ray source 1 is necessary. In order to conduct this alignment, both the semiconductor switch device 70 and the photocathode 42 are normally temporarily replaced with photodiodes. The arrival of the laser pulse at the two points is made to be coincident, to the limits of observational accuracy and jitter, by observing the coincidence of both photodiodes' signal outputs on an oscilloscope, and by adjusting the length beam line path 25. The shortening or lengthening of beam line path 25 is at the scale of 1 psec.apprxeq.0.3 mm. The actual physical beam line paths 24 and 25 are obviously not spatially laid out as illustrated in FIG. 1, which is diagrammatic only. It is within the ability of a user of a laser to adjust the length of an optical path, and to correlate in time events occurring on two such paths. It may be useful to temporally spread out, or dispense the arrival of the laser pulse on beam line 25 at semiconductor switch device 70. In such a case a solution of bromo-benzene in a glass tube may be placed in the beam line 25. It should be understood that it is not absolutely necessary for the laser light pulse that activates the semiconductor switch to be synchronized (temporally coincident) with the laser light pulse that causes the photoemission. Photoemission and electron accumulation can precede acceleration and focusing of the electron beam. In accordance with the preceding discussion, certain adaptations and alterations of the invention will suggest themselves to practitioners in the art of designing x-ray sources. The temporal phasing between the various activities performed in and by the x-ray source in accordance with the present invention is widely variable. There need not even be a one-to-one correspondence between each such activity. For example, the accumulation of electrons in the region between electrode 45 and photocathode 42 could transpire for several laser light pulses. There need not be just one semiconductor switch 70. Another such semiconductor switch, alternately phased, could be applied to the first intermediate voltage power supply 61. The switching of the high voltage power supply need not be by a semiconductor switch, but could, alternatively, be by an appropriately time-synchronized magnetron switch. Indeed, there may be no switching of the high voltage power supply at all. There need not be just one laser used in the x-ray source. Multiple lasers, appropriately phased and adapted in frequency and intensity relative to the separate tasks performed, could be employed. The x-ray source in accordance with the present invention is adaptable to a wide range of (i) x-ray frequencies, (ii) x-ray intensities, and (iii) x-ray pulse lengths from continuous to picosecond and shorter duration. A single x-ray source is, however, normally inefficient over an operational range that is simultaneously broad in all of the many variables. This inefficiency results from a requirement for optimizing the configurations, and spacing, of the photocathode 42 and anode 43 that cannot simultaneously be satisfied for a great range of many differential operational conditions. However, x-ray sources in accordance with the present invention can readily be constructed to efficiently provide a broad range of x-ray frequencies, intensities, and pulse durations that are useful to diverse x-ray spectroscopy and x-ray lithography activities, and to other activities requiring time-resolved x-rays. One embodiment of the invention is a pulsed x-ray source particularly directed for use in x-ray lithography. Using a tantalum film as the photocathode material and 266 nm picosecond pulses from a pulsed mode locked Nd:YAG laser, electron bunches with a charge of 3 nC per pulse have been generated. These electron pulses are accelerated and focused onto a copper anode to produce x-ray pulses with time width of a 20 ps and a brightness of 6.2.times.10.sup.6 cm.sup.-2 sr.sup.-1 at the Ka wavelength (1.54 .ANG.). The use of deep ultraviolet, 193 nm, light combined with the use of pure metal photocathodes is a very efficient as a source of electrons, and hence of x-rays. The advantages of a metal photocathode include a quantum efficiency of the order of approximately 10.sup.-3, a guaranteed long life at a moderate vacuum, and reliability over hundreds of hours of use without incurring any observable deterioration or variation in performance. In addition, the use of pulsed radiation makes possible the generation of a very high peak photocurrent. High power x-ray pulses, with an average power of 5 mW/cm.sup.2 and a peak power of 20 mW/cm.sup.2, can be emitted from surface areas as large as 10-20 cm.sup.2 and larger. The wide area x-ray source in accordance with the present invention can accordingly be used in a simple close-contact arrangement of the X-ray mask and the resists--without the need of focusing! Because of the high intensity, short, X-ray pulses produced, the chemical amplification process in the resist is increased--resulting in a much higher yield. In its wide-area embodiment the present invention is a compact, high intensity, inexpensive, reliable, tunable pulsed x-ray (PXR) source providing reproducible x-ray pulses with an intensity, to approximately 20 mW/cm.sup.2 that is comparable to that of other sources, such as impact tubes and laser-driven plasma-based sources. The wide-area x-ray source consists of a simple plane diode, as illustrated in FIG. 3. The photocathode is made from a pure metal having a low work function, such as, for example, Ta, Sm or Ni. The metal photocathode is irradiated with laser pulses, preferably 193 nm laser pulses. Each electron bunch that is emitted in response to a corresponding laser pulse is accelerated to, and is focused onto, the anode by means of high electric fields. (The focusing is obviously over a much larger area, normally ranging to a circular area of up to 20 cm.sup.2, than is the focusing occurring in the previous embodiment of FIGS. 1 and 2--which previous embodiment may be directed to producing a point x-ray source. Nonetheless, the electron bunch of the wide-area source is spoken of as being "focused" into a wavefront because its dispersion, and its spatial extent (even if over a relatively extended area) are obviously managed and controlled.) The anode is a thin metal foil which emits x-rays in the forward direction under electron impact. Note that this is opposite to the previous embodiment of FIGS. 1 and 2. For this reason the wide area source is sometimes described as "through-path-transmitting", meaning that the electron and the x-ray radiation are along the same axis, and in substantially the same direction. Low Z number metals are preferred for the anode because they emit x-rays at longer wavelengths, such as the characteristic radiation of Al at 0.83 nm. In order to evaluate the output x-ray power of the wide-area X-ray source in accordance with the present invention the main characteristics of its diode construction should be considered. In the pulsed mode of operation, when the transit time t.sub.t of the electrons across the diode is less than the laser pulse duration t.sub.p, the peak current density is given by: EQU J=q/t.sub.p where q is the available charge on the cathode. The maximum value of q per unit area is given by EQU q=E.sub.o .times.V/d where V is the applied voltage and d is the separation of the anode and cathode. If we assume a cathode area of 1 cm.sup.2 d=1 cm and V=200 KV, the transient regime takes place for laser pulses shorter than 100 ps while the available electrons per unit area of the cathode are 1.1.times.10.sup.11 electrons/cm.sup.2. For a photo-cathode quantum efficiency of 10.sup.-4 a laser energy of 1.0 mJ/cm.sup.2 per pulse in required. Assuming an Aluminum anode, the efficiency of the Ka line production will be of the order of 10.sup.-3, which means that 16 .mu.J/cm.sup.2 of x-rays in the forward direction will be produced per pulse. With a quite reasonable 50% transmission of the anode and substrate, a 0.8 .mu.j/cm.sup.2 energy density per pulse is produced on the working surface. This requirement for laser light illumination should be compared with the with certain UV radiation generating lasers (193 nm is discussed below) currently available in the U.S.A. market (circa 1991), which lasers operate at a repetition rate up to 300 Hz. Thus, the average output is 240 .mu.j/cm.sup.2. Therefore, a pulsed laser system using an ArF amplifier with 20 mJ/pulse will be able to irradiate 20 cm.sup.2 of mask area simultaneously. The production of electrons may be increased by a factor of 10 or more by using 193 nm wavelength irradiation because quantum efficiency is related to the laser energy by EQU n=A.sub.(z) (hv-W.sub.o).sup.2 where A.sub.(z) is a constant characteristic of the metal, hv is the laser photon energy and W.sub.o is the work function of the metal. This equation shows that the electron production quantum yield increases with the square of difference between the photon energy and work function. An increase by at least a factor of 10 is realized by use of 193 nm laser pulses. In order to take full advantage of the enhanced quantum efficiency as the work function energy is exceeded, a new and powerful source of 193 nm photons is required. In accordance with the present invention, a new and powerful 193 nm x-ray source is based upon the use of an argon-fluoride laser as an amplifier. It is constructed as follows: A Nd:YLF laser emitting laser light at 1057 nm is up-converted in frequency to generate pulses at 527 nm, 265 nm and 211 nm wavelengths at a 1 KHz repetition rate. This manner of frequency conversion is known in the art. The 527 nm beam is next used to pump a dye laser which emits 728 nm light. The next step involves the frequency mixing, in a Barium Borate (BBO) crystal, of the 728 nm dye laser pulse with the 263 nm fourth harmonic of the frequency-converted primary laser pulse so as to generate a "seed" pulse at 193 nm wavelength. This part has not been done previously. Calculations show that there is a phase matching angle, and because the BBO crystal transmits about 50% at 192 nm, a strong seed pulse is generated for subsequent amplification. While the common argon-fluoride laser has not been used extensively as an amplifier at 193 nm, other excimer lasers, such as the KrF laser at 248 nm, have been used with very satisfactory results for a long time. The complete wide-area x-ray source in accordance with the present invention, as described, is inexpensive. The main components of the system are currently available in the U.S.A. scientific market. The development of the 192 nm "seed" pulse is new, but straightforward. The 300 Hz rate is limited only by the ArF amplifier. However, new excimer amplifiers--such as one from Lambda Physik with a 1 KHz rep-rate--are regularly entering the market. Regenerative amplifiers with YAG and YLF crystals offering repetition rates up to 1 KHz are commercially available now with 1 KHz now, and prototype lasers for laboratory use are available with repetition rates up to 10 KHz. For a complete solid state system, the dye laser/amplifier stage of the present invention can alternatively be replaced with a Ti-sapphire laser. A table top wide-area x-ray source is thus able to produce x-ray radiation with average intensity in the range of 1 mW/cm.sup.2 over an area of 20 cm.sup.2. The x-ray wavelength most convenient will be in the range of 0.1 nm to 1 nm. If, instead of picosecond pulse, longer 10-20 ns pulses are used then higher average powers, can be generated, i.e., 20-30 mW/cm.sup.2 of x-rays in a 20 cm.sup.2 area and with very little shot to shot variation because of the electron saturation of the diode. The x-ray irradiation area can be increased to 40 cm.sup.2 or more without loss in the per cm.sup.2 flux, by simply increasing the diameter of the amplifier. Since the x-ray output of the source is of large size a contact mask will be most suitable, as illustrated in FIG. 3. The mask is normally placed tight against the anode at a separation .ltoreq.5 micrometers. One preferred configuration involves the use of a mask and thick absorber. The thickness of the absorber is desirably more than an order of magnitude larger than the resolution limit. The thick absorber improves the contrast of the mask. Additionally, the distance between x-ray plate and the mask must be as small as possible (less than 5 micrometers). The high peak power of the x-ray will be advantageous for resists with chemical amplification since large numbers of electrons are produced in the exposed area within the short, duration of the x-ray pulse--thus increasing the chemical amplification. A laser-induced pulsed wide-area x-ray source in accordance with the present invention typically generates 1-10 mW/cm.sup.2 of x-rays from picosecond duration laser pulses, and 20-40 mW/cm.sup.2 of x-rays from 20 ns, 193 nm pulses. The pulse repetition rate is 300 Hz minimum, 1,000 Hz typical. A table top size induces stable (.+-.15%) x-ray pulses over large irradiation areas. The x-ray pulses are highly reliable, providing trouble free operation for hundred of hours. In accordance with the preceding explanation, the present invention should be interpreted broadly, in accordance with the following claims, only, and not solely in accordance with that preferred embodiment within which the invention has been taught. |
claims | 1. An autonomous self-powered system for cooling radioactive materials, the system comprising:a pool of liquid including radioactive materials comprised of spent nuclear fuel immersed in the pool of liquid;a closed-loop fluid circuit comprising a working fluid having a boiling temperature that is less than a boiling temperature of the liquid of the pool, the closed-loop fluid circuit comprising, in operable fluid coupling, a hydraulic pump, an evaporative heat exchanger having a tube bundle comprising a plurality of heat exchange tubes at least partially immersed in the liquid of the pool in which an outside of the heat exchange tubes is in direct contact with the liquid of the pool, a turbogenerator, and a condenser in which the working fluid flows therebetween;the closed-loop fluid circuit converting thermal energy extracted from the liquid of the pool into electrical energy in accordance with the Rankine Cycle, the electrical energy powering the pump;wherein the working fluid flows through the tubeside of the plurality heat exchange tubes inside the heat exchange tubes and operates to absorb heat from the pool of liquid, the working fluid inside the tubes being fluidly isolated from the liquid in the pool;wherein the condenser is an induced-flow air-cooled condenser that comprises a housing defining a bottom cool air inlet, a top warmed air outlet at a top, and a blower disposed in the warm air outlet, the blower operably coupled to the air-cooled condenser to draw cool air vertically upwards through the housing from the bottom cool air inlet, over heat exchange tubes disposed in the housing below the blower, and discharge heated air through the top warmed air outlet of the housing, the working fluid being a tube-side fluid flowing vertically downwards through the heat exchange tubes of the air-cooled condenser, wherein the air flows in a first vertical direction from the bottom cool air inlet to the top warmed air outlet and the working fluid flows in a second vertical direction through the heat exchange tubes, the second vertical direction being opposite to the first vertical direction;wherein the air-cooled condenser includes a horizontal working fluid inlet header comprising a first plurality of concentrically arranged toroidal tubes and a horizontal working fluid outlet header comprising a second plurality of concentrically arranged toroidal tubes, the inlet and outlet headers spaced vertically apart in the housing and fluidly coupled to the closed-loop fluid circuit;wherein the heat exchange tubes of the air-cooled condenser are straight tubes each having a first end coupled to the toroidal tubes of the horizontal working fluid inlet header and an opposite second end coupled to the toroidal tubes of the horizontal working fluid outlet header, the heat exchange tubes each being vertically oriented and extending in a vertical direction between the horizontal working fluid inlet and outlet headers, andwherein the vapor phase of the working fluid enters the air-cooled condenser at an inlet and the liquid phase of the working fluid exits the air-cooled condenser at an outlet, wherein the inlet of the air-cooled condenser is located at a greater elevation than the outlet of the air-cooled condenser. 2. The autonomous self-powered system of claim 1 further comprising:the evaporative heat exchanger converting the working fluid from a liquid phase to a vapor phase by transferring the thermal energy from the liquid of the pool to the working fluid;the turbogenerator receiving the vapor phase of the working fluid from the evaporative heat exchanger, the turbogenerator generating the electrical energy by extracting energy from the vapor phase of the working fluid flowing through the turbogenerator;the condenser receiving the vapor phase of the working fluid from the turbogenerator and converting the vapor phase of the working fluid flowing through the condenser back into the liquid phase of the working fluid by removing thermal energy from the working fluid; andthe pump electrically coupled to the turbogenerator so as to be powered by the electrical energy generated by the turbogenerator. 3. The autonomous self-powered system of claim 1 wherein the air cooled condenser further comprises a shroud forming a cavity, the heat exchange tubes located within the cavity of the shroud, the shroud having an air inlet for introducing cool air into the cavity and an air outlet for allowing heated air to exit the cavity, the heat exchange tubes located at an elevation between an elevation of the air inlet and an elevation of the air outlet so that thermal energy transferred from the working fluid flowing to the air through the heat exchange tubes causes a natural convective air flow within the shroud. 4. The autonomous self-powered system of claim 1 wherein the pump forces a liquid phase of the working fluid into the evaporative heat exchanger. 5. The autonomous self-powered system of claim 4 further comprising a reservoir of the liquid phase of the working fluid, the closed-loop fluid circuit comprising the reservoir, and the reservoir located upstream of the hydraulic pump and downstream of the condenser. 6. The autonomous self-powered system of claim 1 wherein the pool of the liquid is at a first pressure and the working fluid within the evaporative heat exchanger is at a second pressure that is greater than the first pressure, the boiling temperature of the working fluid at the second pressure being less than the boiling temperature of the liquid of the pool at the first pressure. 7. The autonomous self-powered system of claim 6 wherein the first pressure is atmospheric and the second pressure is in a range of 250 psia to 400 psia. 8. The autonomous self-powered system of claim 1 wherein the liquid of the pool is water and the working fluid is selected from a group consisting of a refrigerant and a hydrocarbon. 9. The autonomous self-powered system of claim 1 wherein the evaporative heat exchanger is fully immersed in the liquid of the pool and located at a top portion of the pool. 10. The autonomous self-powered system of claim 1 further comprising a rechargeable electrical energy source coupled to the turbogenerator so as to be charged by the electrical energy generated by the turbogenerator. 11. The autonomous self-powered system of claim 1 wherein the evaporative heat exchanger is configured to achieve an internal thermosiphon flow of a liquid phase of the working fluid within the evaporative heat exchanger. 12. The autonomous self-powered system of claim 1 wherein the autonomous self-powered system operates free of electrical energy generated outside of the Rankine Cycle of the closed-loop fluid circuit. 13. The autonomous self-powered system of claim 1 further comprising one or more racks immersed in the pool of liquid, and wherein the radioactive materials comprise spent nuclear fuel rods supported in the one or more racks. 14. The autonomous self-powered system of claim 1 wherein the Rankine Cycle is an Organic Rankine Cycle. 15. A method of cooling a pool of liquid heated by radioactive materials comprising:flowing a working fluid having a boiling temperature that is less than a boiling temperature of the liquid of the pool through a closed-loop fluid circuit that, in accordance with the Rankine Cycle: (1) extracts thermal energy from the liquid of the pool into the working fluid; (2) converts a first portion of the extracted thermal energy into electrical energy that is used to power a hydraulic pump that forces flow of the working fluid through the closed-loop fluid circuit; and (3) transfers a second portion of the extracted thermal energy to a secondary fluid;wherein the radioactive materials are comprised of spent nuclear fuel immersed in the pool of liquid;wherein thermal energy is extracted from the liquid of the pool into the working fluid by an evaporative heat exchanger having a tube bundle comprising a plurality of heat exchange tubes at least partially immersed in the liquid in which an outside of the heat exchange tubes is in direct contact with the liquid of the pool;wherein the working fluid flows through the tubeside of the plurality heat exchange tubes inside the heat exchange tubes and operates to absorb heat from the pool of liquid, the working fluid inside the tubes being fluidly isolated from the liquid in the pool;wherein the second portion of the extracted thermal energy is transferred to air by an induced-flow air-cooled condenser;wherein the induced-flow air-cooled condenser comprises a housing defining a bottom cool air inlet, a top warmed air outlet at a top, and a blower disposed in the warm air outlet, the blower operably coupled to the air-cooled condenser to draw cool air vertically upwards through the housing from the bottom cool air inlet, over heat exchange tubes disposed in the housing below the blower, and discharge heated air through the top warmed air outlet of the housing, the working fluid being a tube-side fluid flowing vertically downwards through the heat exchange tubes of the air-cooled condenser, wherein the air flows in a first vertical direction from the bottom cool air inlet to the top warmed air outlet and the working fluid flows in a second vertical direction through the heat exchange tubes, the second vertical direction being opposite to the first vertical direction;wherein the working fluid in the air-cooled condenser flows in toroidal path via a horizontal working fluid inlet header comprising a first plurality of concentrically arranged toroidal tubes and a horizontal working fluid outlet header comprising a second plurality of concentrically arranged toroidal tubes, the inlet and outlet headers spaced vertically apart in the housing, the inlet and outlet headers fluidly coupled to closed-loop fluid circuit;wherein the heat exchange tubes of the air-cooled condenser are straight tubes each having a first end coupled to the horizontal working fluid inlet header and an opposite second end coupled to the horizontal working fluid outlet header, the heat exchange tubes each being vertically oriented and extending in a vertical direction between the horizontal working fluid inlet and outlet headers, and wherein the vapor phase of the working fluid enters the air-cooled condenser at an inlet and the liquid phase of the working fluid exits the air-cooled condenser at an outlet, wherein the inlet of the air-cooled condenser is located at a greater elevation than the outlet of the air-cooled condenser. 16. The method of claim 15 wherein the evaporative heat exchanger converts the working fluid from a liquid phase to a vapor phase, and is immersed in the liquid of the pool. 17. The method of claim 15 wherein the first portion of the extracted thermal energy is converted into the electrical energy by a turbogenerator that is electrically coupled to the pump. 18. The method of claim 15 wherein the flow of the working fluid through the closed-loop circuit is achieved independent of any electrical energy other than that generated by the Rankine Cycle of the closed-loop fluid circuit. |
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claims | 1. A refueling apparatus for charging a nuclear fuel assembly in a reactor vessel, the refueling apparatus comprising:a refueling unit for loading new nuclear fuel to a reactor core or extracting spent nuclear fuel from the core; anda waveguide sensor unit including an ultrasonic wedge configured to form a Lamb wave, a waveguide with a first end connected to the ultrasonic wedge and with a second end configured to transmit the Lamb wave into liquid metal in the reactor vessel, and an ultrasonic sensor connected to the ultrasonic wedge and configured to sense a reflection signal reflected from an inside of the reactor vessel, the waveguide being formed in a plate shape and mounted in an end of the refueling unit,wherein the waveguide integrally moves with the refueling unit, and the waveguide sensor unit is configured to detect a condition of the inside of the reactor vessel, while the refueling unit refuels the fuel assembly in the reactor vessel, andwherein the refueling unit has a space for the waveguide, and at least a portion of the waveguide is mounted in the refueling unit. 2. The refueling apparatus of claim 1, wherein the waveguide sensor unit is configured to change a radiation angle of a radiation beam depending on a frequency change of an ultrasonic signal incident to the ultrasonic wedge, the radiation beam being radiated from the second end of the waveguide. 3. The refueling apparatus of claim 1, wherein a thickness of the second end of the waveguide transmitting the Lamb wave increases in a lengthwise direction. 4. The refueling apparatus of claim 1, wherein the ultrasonic wedge is made of a material capable of propagating a longitudinal wave velocity of about 1300 m/s to 2000 m/s, and configured to generate an A0 antisymmetric Lamb wave of an range of 0.5 MHz·mm to 2.5 MHz·mm which is a value obtained by multiplying an incident frequency of the Lamb wave and a thickness of the waveguide. 5. The refueling apparatus of claim 1, wherein the ultrasonic wedge is made of a polymer polytetrafluoroethylene wedge and filled with water or glycerin capable of propagating a longitudinal wave velocity of about 1300 m/s to 2000 m/s. 6. A refueling apparatus for charging a nuclear fuel assembly in a reactor vessel, the refueling apparatus comprising:a refueling unit including an extraction unit for extracting the nuclear fuel and a central axis connected to the extraction unit and transferring the extraction unit;a first waveguide sensor unit including a first ultrasonic wedge configured to form a Lamb wave, a first waveguide with a first end connected to the first ultrasonic wedge and with a second end configured to transmit the Lamb wave to a bottom of the extraction unit, and a first ultrasonic sensor connected to the first ultrasonic wedge and configured to sense a reflection signal reflected from an inside of the reactor vessel, the first waveguide being formed in a plate shape and mounted in an end of the extraction unit; anda second waveguide sensor unit including a second ultrasonic wedge configured to form a Lamb wave, a second waveguide with a third end connected to the second ultrasonic wedge and with a fourth end configured to transmit the Lamb wave to a side of the central axis, and a second ultrasonic sensor connected to the second ultrasonic wedge and configured to sense a reflection signal reflected from an inside of the reactor vessel, the second waveguide being formed in a plate shape and mounted in an end of the central axis,wherein the first waveguide sensor unit is configured to detect a condition of a bottom of the extraction unit and the second waveguide sensor unit is configured to detect a condition of the side of the central axis while the refueling unit refuels the reactor vessel, andwherein the extraction unit has a first space for the first waveguide, and at least a portion of the first waveguide is mounted in the extraction unit, and the central axis has a second space for the second waveguide, and at least a portion of the second waveguide is mounted in the central axis. 7. The refueling apparatus of claim 6, wherein the first and second waveguide sensor units are configured to change a radiation angle of a radiation beam depending on a frequency change of an ultrasonic signal incident to the first and second ultrasonic wedges, and the second waveguide sensor unit includes a plurality of waveguide sensor units, the radiation beam being radiated from the second end of the first waveguide and the fourth end of the second waveguide. 8. The refueling apparatus of claim 6, wherein the second and fourth ends have a respective thickness increasing in a lengthwise direction. |
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042591538 | abstract | The proposed device for the removal of fuel assemblies and control and safety system cans from the core of a nuclear reactor comprises a hollow bar, wherein there is installed a main grip adapted for axial movement relative to the bar. At the end of the hollow bar, which faces an element to be withdrawn, there is mounted an auxiliary grip. The internal diameter of the hollow bar is selected so that the latter can envelop the elements being removed from the reactor's core. The length of the bar is selected so that the auxiliary grip can reach the jammed end of an element being withdrawn from the core, while the main grip holds the head of the element. |
053234278 | description | DETAILED DESCRIPTION OF THE INVENTION The feature of this invention that allows the laterally translating permanent cavity seal ring to laterally translate is a specially designed custom bellows used on the outer portion of the seal ring. Most existing welded seal rings used in the nuclear industry utilize either an L-shaped section or a U-shaped section to allow thermal expansion of the reactor. These designs generally have the serious drawback in that they are axisymetric, i.e., the cross section of the seal does not vary at all with the circumference. For these arrangements, significant lateral translation of the reactor tends to cause a shear failure of the flexure at locations 90 degrees off the movement axis. Although traditional bellows with several annular U-shaped folds can accommodate some movement by flexing the bellows (elongating/compressing the opposite sides to rotate the bellow sections), the very large diameter and relatively short height of the seal ring makes this type of mechanical action impractical or impossible. The bellows used in this invention differs in that the radial corrugations extend transverse, rather than parallel, to the end surfaces. The features of this invention are better understood in reference to the drawings. Referring now to FIG. 1 and 2, a pressurized water reactor 1 is positioned within a space 2 defined by a containment wall 4. The reactor is of the pressurized water type, and the figure depicts a fuel rod assembly 6 contained within the reactor vessel 8. The reactor vessel s is supported by means not shown. A coolant flow inlet 10 and a coolant flow outlet 12 penetrate the cylindrical peripheral wall 14 of the reactor vessel 8. The control rods (not shown) that moderate the nuclear reaction are moved vertically by control means 22 extending through the removable reactor vessel head 16. The reactor cavity 2 is divided into an upper portion which defines a refueling canal 18 and a lower portion defining a well 20 that surrounds the lower portion of the reactor vessel 8. A ledge 24 in the containment wall divides the refueling canal 18 from the well 20. The peripheral wall 14 of the reactor vessel has a horizontally extending annular flange 26 at about the elevation of the containment wall ledge 24. The reactor vessel head 16 is removably sealed to the lower portion of the reactor vessel by an annular flange 28 at an elevation above the horizontally extending reactor vessel flange 26. A permanent cavity seal ring 30 of the present invention extends between the containment wall ledge 24 and the horizontally extending flange 26 of the peripheral wall of the reactor vessel. During a refueling operation the refueling canal 18 is first flooded with water and then the reactor head 16 is lifted, thereby exposing the reactor core. The water flooding the refueling canal provides a radiation shield for the exposed core and refueling assemblies. The detailed construction of the annular seal ring 30 of this invention can be better understood by reference to FIG. 3. According to a preferred embodiment of this invention, a cylindrical support 32 is attached to the upper surface 34 of the horizontally extending annular flange 26 and extends vertically upward therefrom. An annular main seal plate 36 extends across most of the gap 2 defined by the containment wall 4 and the peripheral wall 14 of the reactor vessel 8. The main seal plate 36 rests, near its inner edge 38, upon the cylindrical support 32. The upper side 40 of the main seal plate 36 preferably has an annular protrusion 42 extending upwards from a location proximate the main seal plate outer edge 44. A first annular Belleville plate 46 is welded to the annular protrusion near the Belleville plate's inner edge 48. The upper edge 50 of a radially corrugated vertical cylinder 52 is welded to the bottom side 54 of the Belleville plate near the plate's outer edge. The lower edge 56 of the radially corrugated vertical cylinder 52 is welded to the upper side 58 of a second annular Belleville plate 60 near the Belleville plate's inner edge. The outer edge 64 of the second Belleville plate is then sealingly affixed to the containment wall 4. The inner flexible seal 66 is preferably provided by a flexible sealing member 68 having an L-shaped radial cross section. An annular, horizontally extending portion 70 is welded to the upper surface 34 of the annular flange 26. A cylindrical portion 72 is welded at its upper edge to the inner edge 38 of the main seal plate 36. The flexible sealing member 68 is located radially inside the cylindrical support 32 as depicted in FIG. 3. Various arrangements can be used to provide a seal attachment of the second annular Belleville plate 60 to the containment wall 4. A preferred embodiment is depicted in FIG. 3. An annular member 74 having an L-shaped cross section attached to the ledge of the containment wall provides a fixture to weld to the second annular Belleville plate. The annular member 74 is affixed to and sealed to the concrete containment wall 4 by means well known in the construction arts. All materials for the laterally translating permanent cavity seal 30 are preferably stainless steel although other materials with similar qualities of strength, flexibility and corrosion resistance can be equally useful. The main seal plate 36 is preferably 1-1/2 inches (2.5-3.8 cm) thick, providing a strong barrier to falling objects. While the dimensions of the inner and outer diameters of the main seal plate depend upon the sizes of the containment wall 4 and the reactor vessel 8, the inner diameter will generally be between 15 and 20 feet (460 and 730 cm) and the outer diameter between 25 and 30 feet (760 and 910 cm). The cylindrical support 32 that the main seal plate 36 rests upon will also be heavy gauge stainless steel and will be about 6-12 inches (15.2-30.5 cm) in height. The Belleville plates 46, 60, the radially corrugated cylinder, the flexible sealing member 68 and the L-shaped annular member 74 attached to the containment wall 4 are made of much lighter gauge stainless steel, generally 0.04-0.08 inches (0.10-0.20 cm) wall thickness, allowing for the necessary flexibility. A segment of the radially corrugated vertical cylinder 52 is depicted in horizontal cross section in FIG. 4. Its vertical height will range between 6-12 inches (15.2-30.5 cm). The difference between the nominal inner and nominal outer radii of the radially corrugated vertical cylinder is typically 0.2-0.8 inches (0.51-2.03 cm). In other words, the amplitude of each of the corrugations is typically 0.2-0.8 inches (0.51-2.03 cm). The density of corrugations is approximately one per inch (0.4 per cm). During operation of the nuclear reactor 1, radial thermal expansion and contraction of the reactor vessel 8 is accommodated by the inner connection arrangement. Radial expansion of the reactor vessel 8 moves the horizontally extending annular flange 26 radially outward relative to the main seal plate 36. The cylindrical support 32 slips radially outward beneath the main seal plate 36. The lower, annular portion 70 of the inner flexure member 66 that is attached to the annular flange 26 moves radially outward relative to the main seal plate 36 as depicted in FIG. 5. Radial contraction of the reactor vessel 8 relative to the containment wall 4 involves movements in opposite directions from that described above. A lateral translation of the reactor vessel 8 relative to the containment wall 4 is mainly accommodated by the outer attachment arrangement comprising the Belleville plates 46, 60 and the radially corrugated vertical cylinder 52. FIG. 6a is a radial view of a section of the outer attachment arrangement in a neutral position. FIG. 6b shows the effect of lateral movement of the reactor vessel 8 (in a direction indicated by the arrow) on the outer attachment arrangement. Lateral movement of the main seal plate 36 in the horizontal plane will deform the upper end of the radially corrugated vertical cylinder 52 in the direction of the lateral movement. The upper end of the radially corrugated vertical cylinder, being attached to the first Belleville plate 46, will move rigidly with movement of the main seal plate 36 and the reactor vessel 8. The lower end of the radially corrugated vertical cylinder, being welded to the second Belleville plate 60 that is affixed to the containment wall 4, will typically remain in place. The flexible sealing member 68 does not significantly deform during a purely lateral movement of the reactor vessel 8. Axial thermal expansion/contraction of the reactor vessel 8 relative to the containment wall 4 is accommodated by flexure of the first 46 and second 58 Belleville plates as depicted in FIG. 7. Another embodiment of the outer attachment arrangement that provides for an equivalent degree of movement is arranged such that the radially corrugated vertical cylinder 52 is welded at its bottom edge to the upper side of the inner, first annular Belleville plate, and extends upwards therefrom. The outer, larger diameter, second annular Belleville plate is welded at its lower side proximate its inner edge to the upper edge of the radially corrugated cylinder. The second Belleville plate's outer edge is then sealingly affixed to the containment wall 4. This arrangement provides equivalent freedom of movement to those embodiments described above. It will be understood that the above description of the present invention is capable of various additional modifications, changes and adaptations and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims. |
summary |
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