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052710459 | abstract | An advanced control room complex for a nuclear power plant, including a discrete indicator and alarm system (72) which is nuclear qualified for rapid response to changes in plant parameters and a component control system (64) which together provide a discrete monitoring and control capability at a panel (14-22, 26, 28) in the control room (10). A separate data processing system (70), which need not be nuclear qualified, provides integrated and overview information to the control room and to each panel, through CRTs (84) and a large, overhead integrated process status overview board (24). The discrete indicator and alarm system (72) and the data processing system (70) receive inputs from common plant sensors and validate the sensor outputs to arrive at a representative value of the parameter for use by the operator during both normal and accident conditions, thereby avoiding the need for him to assimilate data from each sensor individually. The integrated process status board (24) is at the apex of an information hierarchy that extends through four levels and provides access at each panel to the full display hierarchy. The control room panels are preferably of a modular construction, permitting the definition of inputs and outputs, the man machine interface, and the plant specific algorithms, to proceed in parallel with the fabrication of the panels, the installation of the equipment and the generic testing thereof. |
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053751523 | description | DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the invention comprises a chemical process for preventing the formation of cobalt-contaminated oxide films on the surfaces of metal structures providing the cooling water circuits of water-cooled nuclear reactors, such as inner portions of pipes, conduits, vessels, tanks, chambers, etc. Cobalt derived from metal alloy materials utilized in nuclear reactor plants is known as a major source of radiation and, in turn, is a health hazard to operating and maintenance personnel working about the nuclear reactor structures. Cobalt, particularly the Co-60 isotope, is carried in the cooling water throughout the nuclear reactor coolant circuit or system and becomes entrained and/or embedded in the mass of oxides commonly forming and accreting over the exposed metal surfaces of vessels, conduits, etc. of the cooling water circuit system. Reducing the presence of cobalt by replacing cobalt-containing alloys with alloys free of cobalt to minimize its source is expensive and most often impractical. Chemical decontamination procedures for removing cobalt-contaminated oxide films from inside surfaces of the cooling water circuit have been proposed whereby the hazardous radiation fields are substantially reduced through oxide film removal by chemical means. However, due to extremely high corrosion rates, the decontaminated surfaces rapidly pick up Co-60 isotope from the circulating cooling water and retain it in the accreting body of oxides forming on exposed metal surfaces. Thus, radiation levels measured one cycle after decontamination are frequently as great as before decontamination. In accordance with the method of the present invention, a chemical technique is provided which controls and/or minimizes contamination in water-cooled nuclear fission reactor systems prior to any significant initial contamination or following decontamination. By minimizing recontamination, the method of this invention can be a more effective means of reducing radiation exposure of personnel in a boiling water nuclear reactor. The chemical measures of this invention entail a combination of conditions that reduce the soluble (ionic) Co-60 concentration in reactor cooling water and preoxidize the surfaces of the cooling water circuit with an oxide film which is substantially free of Co-60. The steps of the invention comprise adjusting the pH of the cooling water circulating within the cooling water circuit to a slightly basic condition of about 7.5 to about 8 when measured at a water temperature of about 25.degree. C., and adding a solution of an iron compound, including, but not limited to, freshly prepared insoluble species such as Fe(OH).sub.3, Fe.sub.2 O.sub.3 and Fe.sub.3 O.sub.4, or water-soluble compounds such as ferrous oxalate and ferric citrate, in amounts sufficient to maintain a soluble iron concentration in the cooling water in the range of 50 to 200 ppb. Under these conditions, preferably augmented by elevated water temperatures, the soluble (ionic) Co-60 in the reactor cooling water is effectively scavenged. Moreover, while the soluble Co-60 concentration in the cooling water is reduced, the surfaces of the cooling water circuit can be oxidized to form a substantially cobalt-free protective film prior to initial operation or following cobalt purging. Preferred conditions for the practice of this invention comprise adjusting the cooling water pH to about 7.5 to about 8 with adequate Fe(OH).sub.3 addition to maintain the iron concentration at approximately 200 ppb with the cooling water at a temperature of at least about 230.degree. C. Generally optimum effects are obtained when these conditions of pH, iron concentration and temperature are maintained in the cooling water of the reactor coolant system over a period of at least about 500 hr. The elevated temperatures of the cooling water can be provided without nuclear fission-produced heat in accordance with a pre-startup treatment by any suitable means or source, such as heat generated by recirculation pumps which drive the cooling water through the reactor coolant system. In a typical reactor pre-startup treatment in accordance with the invention, suitable amounts of ferric hydroxide in a slightly basic water solution are injected into the reactor coolant for attaining the desired pH of about 8 and iron concentration of about 200 ppb, with the pH being determined at a water temperature of about 25.degree. C. The temperature of the cooling water is maintained at about 230.degree. C. or higher. Given these conditions, the soluble Co-60 in the cooling water can be reduced to less than about 1% of the total Co-60 concentration in the reactor water. To foster oxidation of the surfaces of the cooling water circuit upon purging of Co-60 from the cooling water, the dissolved oxygen content in the reactor cooling water is maintained at about 200 to about 400 ppb. The oxygen can be provided by introducing oxygenated water, such as control rod drive water, or by injecting oxygen. Preferably the operations of pH adjustment combined with iron solution addition for Co-60 purging of the cooling water system, and oxygen level control are carried out as long as is practical before startup of the nuclear reactor, for example, at least about 500 hr. Following starting up of the water-cooled nuclear fission reactor, the iron content of the cooling water may be depleted rapidly, whereby a high iron solution injection rate can be appropriate or required to maintain the iron content in the range of about 50 to about 100 ppb. The pH of the water should be maintained in the range of about 7.5 to about 8. Then the nuclear reactor is operated under the given conditions for approximately 500 hr before the iron solution injection is terminated. At this stage the iron content of the cooling water should be maintained at about 5 ppb. This can be achieved by means of feedwater quality control. |
052681289 | summary | BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a method and apparatus for cleaning particulate materials such as soils which are contaminated with a variety of contaminants such as heavy metals, radioactive compounds and organics, often in combination, through a combination of leaching, washing, attrition scrubbing, countercurrent flow size separation and density separation. This invention further relates to the recovery of such contaminants following removal from the soils, for additional processing, recycling or disposal. 2. Background Information Contaminated soil is becoming a more common environmental problem. The contaminants can include heavy metals, such as for instance, copper, lead and mercury; radioactive species such as for example, radium, uranium and thorium; and organics such as for example, oils, polychlorinated biphenyls, flue soot and others. Various techniques have been developed to remove specific contaminants. For instance, heavy metals are known to be found predominantly in the silt, humic or clay fraction of soil. Hence, they can be removed by size separation such as tiltable tables, concurrent flow in a mineral jig and chemical techniques such as the use of precipitants. The radioactive compounds when originating as a spill can be removed to a large extent by leaching. Since these compounds are often also present in the finer particles, the most severely contaminated fraction can also be removed by countercurrent flow size separation. Organics can be removed by washing with surfactants, thermal treatment or biological processes. Special problems develop when the different types of contaminants are present in soil. Generally, biological or thermal processes are more effective for removing organics than washing. However, toxic inorganics such as lead or chromium (+6), if present, deactivate biological systems due to their toxicity and cause air pollution problems for thermal processes. In addition, thermal processes may mobilize otherwise fixed contaminants in the treated soil. Radioactive contamination (e.g., uranium, thorium radium, etc.) can be removed by soil washing. Soil washing provides a means to process soils having multiple contaminants. The washed soil is accessible to further biological or thermal treatment. Inorganic and radioactive compounds may be separated from organics for separate sale or disposal. Many soil washing processes are available. Most use mining equipment to provide intimate soil/surfactant contact. U.S. Pat. No. 4,783,253 discloses a process for separating radioactive contaminants from soil using a concurrent flow of water to float away lighter uncontaminated particles from heavy contaminated particles. The slurry of lighter particles is dewatered using a spiral classifier, centrifuge, filter or the like. U.S. Pat. No. 4,783,263 is directed to a process for removing toxic or hazardous substances, in particular organics, from soils and the like by converting the material to a slurry adding surfactants and/or alkaline agents, and concentrating the toxic substance in the liquid phase preferably with a modifier in a froth flotation cell. Some of the limitations of the currently used processes are that they are optimized for removing only one type of contaminant or for cleaning only one type of soil, they are geared to cleaning the larger particles while concentrating the fines in a fraction for later disposal, and they often use filtration for water removal which is a capital intensive operation with high operating costs. Once the contaminants have been removed from the soil or other particulate material they must in turn be recovered for further processing, such as mining and/or smelting in the case of heavy metals, or disposal, for example, through mixing with a fixative material such as concrete. The ability to recover contaminants from the cleaning system is to a large extent dependent upon the method by which the contaminants were removed from the soil in the first instance. Mineral extraction in general and soil washing in particular often require the oxidation of the metals and sometimes the organic fraction of the soil for the removal of the metals. Radioactive metals are also included with heavy metals requiring oxidation since most radioactive materials are also inorganic heavy metals, such as uranium, thorium or radium. Some typical oxidants include nitric acid, sodium hypochlorite and calcium hypochlorite. However, the use of nitric acid is generally not practical due to the fact that nitric acid is nonselective in its action, dissolving the rock matrix as well as oxidizing and dissolving the metal of interest, it is expensive, and results in nitrate-laden waste liquors which can present environmental hazards unless treated. Sodium hypochlorite is expensive to use because commercial solutions are supplied as a 15% liquid which increases the freight cost. Calcium hypochlorite introduces large amounts of calcium ion into the leachate solution when used in quantities sufficient to oxidize the metal, and the calcium ions can then precipitate if carbonate bleach liquors are used or if the leachate solution is left standing in contact with air. This calcium carbonate precipitate is difficult to handle and can clog processing equipment. In addition, if common soaps are used to remove organics, the high calcium ion content tends to precipitate some of the soap which requires use of additional soap. There is a need therefore for an improved process and apparatus for treating particulate materials, such as soil and the like, contaminated with mixed wastes such as radioactive materials, organics and heavy metals. There is a further need for such a process and apparatus which separates organic and inorganic contaminants thereby allowing for optimum disposal routes or post treatment strategies to be used on the concentrated contaminated fractions. There is also a need for such a process and apparatus which produces a high solids content fines stream. There is yet another need for such a process and apparatus which is not capital intensive, is economical to operate and can be made portable for on-site treatment. There is a further need for a system that can effectively recover the contaminants once they have been removed from the soil, requiring a minimal amount of equipment, chemicals, and being portable to the job site, which further allows for the processing of recovered contaminants, such as metals, through mining and/or smelting operations, and allows for effective leach-resistant fixation of contaminants which are to be disposed. SUMMARY OF THE INVENTION These and other needs are satisfied by the invention which is characterized by treating particulate materials such as soils, sludges, sediments, scrap yard dust and the like, contaminated with radioactive compounds, heavy metals, and organics, either singly or in combination, by first washing the particulate material with a contaminant mobilizing solution which can consist of leaching solutions, surfactants, and mixtures thereof to mobilize soluble and dispersible contaminants in a liquid phase of the contaminant mobilizing solution. Mechanical separation means are then used to separate large particles of a size substantially free of residual contamination, typically larger than 5 mm, from intermediate sized particles and fines in the contaminant mobilizing solution. These separated large particles are washed with a water based cleaning solution to produce recovered particulate material. Fines are size separated from the intermediate sized particles in the contaminant mobilizing solution with a countercurrent flow of the contaminant mobilizing solution to form a waste slurry. The size separation is preferably performed in a mineral jig. The intermediate sized particles from which the fines have been separated are attrition abraded to dislodge attached fines. These dislodged fines are then separated from the intermediate sized particles by a countercurrent flow of wash water to form additional waste slurry and an effluent of the intermediate sized particles and wash water. The intermediate sized particles are dewatered to produce additional recovered particulate material. If the particulate material has been contaminated with insoluble heavy metals, they can be separated from the effluent of intermediate sized particles and wash water emerging from the second size separation by density separation such as by a cross-current pulsed flow of wash water prior to dewatering. According to the present invention, the contaminants removed from the particulate matter are treated to effect their destruction, collection and/or disposal. The insoluble heavy metals may be treated with an oxidizing agent, such as Cl.sub.2 and/or organics may be treated with a reducing agent, such as H.sub.2. The oxidizing agent makes the heavy metals more soluble in the wash water process stream, and the reducing agent destroys the organics and/or makes them more environmentally acceptable. The oxidizing agent may also be used to treat certain organics. The clean particulate material can then be separated from the wash water process stream, and the heavy metals can be precipitated, using, for example, Na.sub.2 SiO.sub.3 as the precipitant, and adjusting the pH of the wash water process stream to 8-10, preferably 9. Additional oxidizing or reducing agent can then be added to the wash water process stream for recycle. The scrubbing of the particles removes the mineral slimes or fine particles adhering to the intermediate sized particles. As is known, these dislodged fine particles have a very large surface area which is chemically active. Some solubilized contaminants have a high affinity for the surface area of these fine particles. Hence, in accordance with the broad process defined by the invention, the dissolved contaminants are drawn off in the first size separation before scrubbing to dislodge fines. These dislodged fines are then separated in a second sizing countercurrent flow using wash water. In applications in which contamination of dislodged fines with dissolved contaminants is not a problem, another attrition abrading step can be carried out prior to the initial size separation of fines using a countercurrent flow of the contaminant mobilizing solution. The invention is further characterized by using the water obtained by dewatering the intermediate sized particles remaining after the second size separation as the wash water for the second size separating countercurrent flow. The countercurrent flow rate in the size separating steps can be adjusted to adjust the size of the fines removed. The adjustment is made to balance the percentage of soil particles recovered and allowable levels of residual contamination. Typically, fines smaller than about 60 microns are removed in the waste slurry. The actual size removed will be dependent upon the contaminant distribution as a function of particle size, and can vary from less than 200 to 10 microns. Another novel aspect of the invention is the operation of a mineral jig in a countercurrent flow mode to effect size separation of fines from the slurry while simultaneously washing the particulate material. In one stage the mobilizing solution is used to produce the countercurrent flow, while wash water is used in the final size separating stage for removing fines. The waste slurry from the two countercurrent flow size separating steps containing the fines, dissolved metals including the radioactive contaminants, and the organics, is further treated to remove the fines and contaminants and to produce clean contaminant mobilizing solution which is recirculated. In one embodiment of the invention the dissolved metals are precipitated by a sulfide. In a preferred embodiment, the dissolved metals are made more soluble in the contaminant mobilizing solution with an oxidizing or reducing agent, and then, after clean particulate material is removed, these dissolved metals are precipitated, e.g., with Na.sub.2 SiO.sub.3. The precipitates and fine soil particles are removed by dewatering and the decontaminant mobilizing solution can be further treated such as in an ion exchange bed to remove radioactive soluble contaminants and passed through a carbon bed to remove the organic load before being recycled. Alternatively, the contaminant mobilizing solution (process stream) can be treated with CaCl.sub.2 to remove contaminated surfactants for total removal of the surfactants from the process stream. |
052788768 | claims | 1. A head for closing a nuclear reactor pressure vessel shell comprising: an arcuate dome having a convex outer surface and a concave inner surface, and including an integral annular head flange extending around a perimeter thereof, said head flange having an annular head mating surface for sealingly mating with said shell upon assembly therewith and a head internal passage extending through said head flange with a first port on said head mating surface; and a vent line having a proximal end disposed in flow communication with said head internal passage, and a distal end disposed in flow communication with an inside of said dome for channeling a fluid therebetween, said vent line being fixedly joined to said dome and carried therewith when said head is assembled and disassembled from said shell. said head flange further includes a top surface spaced above said head mounting surface, and said head internal passage includes a second port thereon; said dome includes a nozzle extending therethrough from said outer surface to said inner surface; and said vent line extends between said top surface and said nozzle, with said proximal end being disposed in flow communication with said second port at said top surface, and said distal end being disposed in flow communication with said dome nozzle. an integral annular shell flange extending around a perimeter thereof, said shell flange having an annular shell mating surface sealingly mating with said head mating surface, a shell outer surface disposed perpendicularly to said shell mating surface, and a shell internal passage extending through said shell flange with a shell first port on said shell mating surface disposed in flow communication with said head first port, and a shell second port disposed on said shell outer surface. said head flange further includes an inside surface facing radially inwardly above said head mating surface, and said head internal passage includes a second port thereon; and said vent line extends from said flange inside surface along said dome inner surface, with said proximal end being disposed in flow communication with said head second port at said flange inside surface, and said distal end being open inside said dome in flow communication therewith. an integral annular shell flange extending around a perimeter thereof, said shell flange having an annular shell mating surface sealingly mating with said head mating surface, a shell outer surface disposed perpendicularly to said shell mating surface, and a shell internal passage extending through said shell flange with a shell first port on said shell mating surface disposed in flow communication with said head first port, and a shell second port disposed on said shell outer surface. 2. A head according to claim 1 wherein said vent line is disposed externally of said dome and extends along said dome outer surface. 3. A head according to claim 2 wherein: 4. A head according to claim 3 in combination with said shell to define a pressure vessel, said shell further comprising: 5. A pressure vessel according to claim 4 further including an annular vent seal disposed between said head and shell mating surfaces around said respective first ports thereof for restricting leakage of said fluid from said vent line and between said head and shell flanges. 6. A pressure vessel according to claim 5 further including at least one annular head seal disposed between said head and shell mating surfaces and spaced radially outwardly from said vent seal. 7. A head according to claim 1 wherein said vent line is disposed internally of said dome and extends along said dome inner surface. 8. A head according to claim 7 wherein: 9. A head according to claim 8 in combination with said shell to define a pressure vessel, said shell further comprising: 10. A pressure vessel according to claim 9 further including an annular vent seal disposed between said head and shell mating surfaces around said respective first ports thereof for restricting leakage of said fluid from said vent line and between said head and shell flanges. 11. A pressure vessel according to claim 10 further including at least one annular head seal disposed between said head and shell mating surfaces and spaced radially outwardly from said vent seal. |
047449381 | claims | 1. A method for producing a fissionable deposit of selectively ultralow mass for neutron dosimetry, comprising the steps of: (a) spacing in opposing relation a substrate and an alpha-emitting parent source which decays to implant into the substrate a fissionable daughter ejected from the parent source as a result of the decay; and (b) holding the opposing relation for a period of time until the parent source decays to form a corresponding mass of isotopically pure fissionable daughter uniformly on the substrate. wherein step (b) comprises the substep of rotating the respective, opposing holding means relative to each other to promote uniformity of the implantation of the fissionable daughter on the substrate. selecting the parent source so that the fissionable daughter is .sup.239 Pu. selecting the parent source so that the fissionable daughter is .sup.235 U. selecting the parent source so that the fissionable daughter is .sup.237 Np. selecting the parent source so that the fissionable daughter is .sup.238 U. wherein step (b) further comprises the substep of individually rotating each of the plurality of substrates while at least one of the holding means is rotated with respect to the other holding means. performing a calibration by measuring the amount of the fissionable daughter implanted on the substrate during the period of time of the holding of step (b); and subsequently implanting a predetermined amount of the fissionable daughter in a further substrate by repeating the steps (a) and (b) with the further substrate, wherein the period of time is selected to form the predetermined amount of the fissionable daughter on the further substrate. (a) first means for receiving an alpha-emitting parent source; and wherein the parent source and the substrate are held in an opposing, spaced relation so that a fissionable daughter that is ejected from the parent source is implanted isotopically pure and uniformly into the substrate. (c) a plurality of substrates held by the second means; and (d) rotation means for rotating the first and second means relative to each other for uniformly implanting the fissionable daughter in each of the plurality of substrates. 2. The method as recited in claim 1, wherein step (a) further comprises the substep of locating the parent source and the substrate on respective, opposing holding means, and 3. The method as recited in claim 1, wherein step (a) further comprises the substep of: selecting the parent source from the group consisting of .sup.239 Pu, .sup.241 Am, .sup.242 Pu and .sup.243 Am. 4. The method as recited in claim 1, wherein step (a) further comprises the substep of: 5. The method as recited in claim 1, wherein step (a) further comprises the substep of: 6. The method as recited in claim 1, wherein step (a) further comprises the substep of: 7. The method as recited in claim 1, wherein step (a) further comprises the substep of: 8. The method as recited in claim 2, wherein step (a) further comprises the substep of locating a plurality of substrates on the respective holding means, and 9. The method as recited in claim 8, wherein each of the plurality of substrates is provided in the form of a wafer. 10. The method as recited in claim 8, wherein the respective holding means for the parent source is a disk having its axis aligned with an axis of relative rotation of the other holding means, and the parent source is provided in the form of a layer on the disk. 11. The method as recited in claim 1, further comprising the steps of: 12. An apparatus for producing a fissionable deposit of selectively ultralow mass for neutron dosimetry, comprising: (b) second means for receiving a substrate, 13. The apparatus as recited in claim 12, further comprising: 14. The apparatus as recited in claim 13, wherein each of the plurality of substrates is a solid state track recorder. 15. The apparatus as recited in claim 14, wherein each solid state track recorder is a wafer selected from the group consisting of mica, quartz and zircon. 16. The apparatus recited in claim 12, wherein the first means is of nickel, and the parent source is in the form of a layer formed thereon. 17. The apparatus as recited in claim 13, wherein the rotation means includes means for individually rotating each of the plurality of substrates on said second means while rotating at least one of said first and second means relative to the other. 18. An implanted substrate prepared by the process of claim 1, having a predetermined amount of the fissionable daughter implanted therein as a result of specifying the period of time of the holding step (b). 19. An implanted substrate prepared by the process of claim 2, having a predetermined amount of the fissionable daughter implanted therein as a result of specifying the period of time of the holding step (b). 20. An implanted substrate prepared by the process of claim 8, having a predetermined amount of the fissionable daughter implanted therein as a result of specifying the period of time of the holding step (b). 21. The apparatus of claim 17, wherein the apparatus is capable of calibration as a function of the radial position of the substrate from the axis of relative rotation of said first and second means. |
051475979 | claims | 1. A method for retarding buildup of radioactive materials on a water exposed steel surface of a pipe which forms a part of a water system of a light water nuclear reactor, comprising the steps of: preparing said water exposed steel surface to obtain a clean base metal starting surface; depositing a chromium film at least five hundred Angstroms thick on said pipe surface from a solution of chromic acid and sulfuric acid under controlled electrochemical deposition conditions; exposing said deposited chromium film and said underlying base metal to a gaseous oxygen source at temperatures between 150.degree. C. and 450.degree. C. to obtain a thin stabilized chromium-rich oxide film on the exposed surface of said deposited chromium film; and, using said chromium-coated pipe with an oxide film as a portion of the water system of the light water nuclear reactor. 2. A method as in claim 1 wherein said oxygen source comprises air. 3. A method as in claim 1 wherein said oxygen source further comprises a minor amount of water vapor. |
abstract | The invention relates to a device (1) for producing radioisotopes by irradiating a target fluid using a particle beam (13). This device comprises an irradiation cell (7) that includes a cavity (3) for receiving the target fluid. A non-cryogenic cooling device cools the walls of the cavity (3). The cavity (3) has an inclined surface (15) downwardly delimiting the cavity (3) so as to evacuate the target fluid, which condenses on contact with the cooled walls, under gravity towards a metal foil (4) which closes off this cavity (3). The inclined surface (15) intersects the plane formed by the metal foil (4), making an acute angle (a) with said plane, so as to form with the metal foil (4) a wedge-shaped zone (18) capable of collecting, by gravity, the condensed target fluid. |
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claims | 1. A method of treating a patient with radiation, the method comprising:acquiring three-dimensional image data from the patient using a radiation source while the patient is in a treatment position;defining a target region while the patient remains in the treatment position;generating an initial contour set for the target region from one of a contour library and a prototype contour set;generating a treatment plan based on the defined target region and the three-dimensional image data while the patient remains in the treatment position; andwhile the patient remains in the treatment position, delivering radiation to the target region using the radiation source according to the treatment plan. 2. The method of claim 1, wherein the target region is defined using one or more predefined shapes. 3. The method of claim 1 further comprising the act of defining an avoidance region with one or more predefined shapes. 4. The method of claim 1 further comprising the act of defining an amount of radiation to be delivered to the target region. 5. The method of claim 4 further comprising the act of generating a dose distribution based on the amount of radiation to be delivered to the target region. 6. The method of claim 5 further comprising the act of generating a number of treatment fractions based on the dose distribution. 7. The method of claim 1 wherein the target region is an irregular shape and wherein a plurality of the predefined shapes can be used to define the irregular shape. 8. The method of claim 1 wherein the act of defining a target region includes the act of utilizing at least one predefined shape to define the target region in a transverse slice of the image data. 9. The method of claim 8 wherein the act of defining a target region includes the act of automatically defining the target region three-dimensional space based on two-dimensional contours drawn in any combinations of coronal slice planes, sagittal slice planes, and transverse slice planes. 10. The method of claim 1 wherein the target contour is manually edited. 11. The method of claim 1 wherein the generation of contours uses deformable registration. 12. The method of claim 1 wherein the image data is acquired using a radiation therapy system having an imaging apparatus. 13. The method of claim 12 wherein the image data is acquired with a radiation beam having a fan-shaped geometry. 14. The method of claim 12 wherein the image data is acquired with a radiation beam having a multi-slice geometry. 15. The method of claim 12 wherein the image data is acquired with a radiation beam having a cone-beam geometry. 16. The method of claim 12 wherein the imaging apparatus uses megavoltage energies. 17. The method of claim 12 wherein the imaging apparatus uses kilovoltage energies. 18. The method of claim 12 wherein the imaging apparatus uses emitted photons. 19. The method of claim 12 wherein the imaging apparatus is a magnetic resonance imaging system. 20. The method of claim 1 wherein the act of acquiring image data includes the act of pre-processing the image data to generate the treatment plan. 21. The method of claim 20 wherein the act of pre-processing the image data includes adjusting the density content of the image data. 22. The method of claim 1 wherein the act of delivering radiation to the target region includes the act of delivering photon radiation. 23. The method of claim 1 wherein the act of delivering radiation to the target region includes the act of delivering proton radiation. 24. The method of claim 1 wherein the act of delivering radiation to the target region includes the act of delivering therapeutic particle radiation. 25. The method of claim 1 wherein the act of generating the treatment plan includes the act of incorporating previously delivered dose information. 26. The method of claim 1 wherein the patient remains substantially stationary between the act of acquiring image data from the patient and the act of delivering radiation to the target region. 27. The method of claim 1 wherein the patient lies on a platform, and wherein the patient remains on the platform between the act of acquiring image data from the patient and the act of delivering radiation to the target region. 28. The method of claim 1 wherein the act of generating the treatment plan includes generating a conformal treatment plan and further comprises the act of optimizing the conformal treatment plan. 29. The method of claim 1 wherein the act of generating the treatment plan includes generating an IMRT treatment plan and further comprises the act of optimizing the IMRT treatment plan. 30. The method of claim 1 wherein the treatment plan is used for subsequent treatment fractions. 31. The method of claim 1 wherein the act of generating the treatment plan includes the act of utilizing class solutions. 32. The method of claim 1 wherein the act of generating the treatment plan includes the act of utilizing optimization templates. 33. The method of claim 1 wherein the act of generating the treatment plan includes the act of performing a pre-determined number of iterations. 34. The method of claim 1 further comprising the act of acquiring subsequent image data and the act of generating a subsequent treatment plan based on the subsequently acquired image data. 35. The method of claim 34 wherein the subsequent treatment plan is based at least partially on one or more previous treatment plans. 36. The method of claim 35 wherein the act of generating the treatment plan includes the act of utilizing a biological model. 37. The method of claim 34 wherein the subsequent treatment plan is based at least partially on a previously delivered dose to the patient. 38. The method of claim 37 wherein the previously delivered dose includes an accumulation of a plurality of doses, and wherein the plurality of doses is determined based on a deformation process. 39. The method of claim 1 further comprising the act of generating a subsequent treatment plan, and wherein the subsequent treatment plan includes at least one treatment fraction, wherein the subsequent treatment plan is optimized for at least one treatment fraction. 40. The method of claim 1 wherein the treatment plan includes at least two treatment fractions, and wherein the patient is aligned for delivery of the second treatment fraction using the image data. 41. The method of claim 1 wherein the treatment plan includes at least two treatment fractions, and wherein the patient is positioned for delivery of the second treatment fraction using one of contour information, image information, and dosimetric information. 42. The method of claim 1 further comprising the act of generating a quality assurance plan adapted to validate a dose delivery in a phantom. 43. The method of claim 42 wherein the treatment plan includes a plurality of fractions, and further comprising the act of dividing one of the fractions into a first sub-fraction and a second sub-fraction, and wherein the treatment plan dosimetry is validated after delivery of the first sub-fraction and before completing delivery of the second sub-fraction. 44. The method of claim 1 wherein the radiation source is in communication with an integrated database. 45. The method of claim 1 wherein the radiation source includes a single source point for a radiation beam used in the acquisition of image data from the patient and a radiation beam used in the delivery of radiation to the target region. 46. The method of claim 1 wherein the acquiring, defining, generating an initial contour set, generating a treatment plan, and delivering acts can be completed in less than thirty minutes. 47. The method of claim 1 wherein the radiation source includes a first source point for a radiation beam used in the acquisition of image data from the patient and a second source point for a radiation beam used in the delivery of radiation to the target region. 48. A method of treating a patient with radiation, the method comprising:acquiring three-dimensional image data from the patient using a radiation source while the patient is in a treatment position;defining a target region while the patient remains in the treatment position;generating a treatment plan based on the defined target region and the three-dimensional image data while the patient remains in the treatment position;while the patient remains in the treatment position, delivering radiation to the target region using the radiation source according to the treatment plan;acquiring subsequent image data; andgenerating a subsequent treatment plan based on the subsequently acquired image data, wherein the subsequent treatment plan is based at least partially on a previously delivered dose to the patient, andwherein the previously delivered dose includes an accumulation of a plurality of doses, and wherein the plurality of doses is determined based on a deformation process. 49. The method of claim 48, wherein the target region is defined using one or more predefined shapes. 50. The method of claim 48 wherein the patient remains substantially stationary between the act of acquiring image data from the patient and the act of delivering radiation to the target region. 51. The method of claim 48 wherein the patient lies on a platform, and wherein the patient remains on the platform between the act of acquiring image data from the patient and the act of delivering radiation to the target region. 52. The method of claim 48 wherein the radiation source includes a single source point for a radiation beam used in the acquisition of image data from the patient and a radiation beam used in the delivery of radiation to the target region. 53. The method of claim 48 wherein the radiation source includes a first source point for a radiation beam used in the acquisition of image data from the patient and a second source point for a radiation beam used in the delivery of radiation to the target region. 54. A method of treating a patient with radiation, the method comprising:acquiring three-dimensional image data from the patient using a radiation source while the patient is in a treatment position;defining a target region while the patient remains in the treatment position;generating a treatment plan based on the defined target region and the three-dimensional image data while the patient remains in the treatment position; andwhile the patient remains in the treatment position, delivering radiation to the target region using the radiation source according to the treatment plan, andwherein the act of acquiring image data includes the act of pre-processing the image data to generate the treatment plan, andwherein the act of pre-processing the image data includes adjusting the density content of the image data. 55. The method of claim 54, wherein the target region is defined using one or more predefined shapes. 56. The method of claim 54 further comprising the act of defining an avoidance region with one or more predefined shapes. 57. The method of claim 54 further comprising the act of defining an amount of radiation to be delivered to the target region. 58. The method of claim 57 further comprising the act of generating a dose distribution based on the amount of radiation to be delivered to the target region. 59. The method of claim 58 further comprising the act of generating a number of treatment fractions based on the dose distribution. 60. The method of claim 54 wherein the target region is an irregular shape and wherein a plurality of the predefined shapes can be used to define the irregular shape. 61. The method of claim 54 wherein the act of defining a target region includes the act of utilizing at least one predefined shape to define the target region in a transverse slice of the image data. 62. The method of claim 61 wherein the act of defining a target region includes the act of automatically defining the target region three-dimensional space based on two-dimensional contours drawn in any combinations of coronal slice planes, sagittal slice planes, and transverse slice planes. 63. The method of claim 54 wherein the act of defining a target region includes the act of using an automatically generated contour. 64. The method of claim 63 wherein the automatically generated contour is adapted to be manually edited. 65. The method of claim 54 wherein an initial contour set is generated from one of a contour library and a prototype contour set. 66. The method of claim 65 wherein the generation of contours uses deformable registration. 67. The method of claim 66 wherein the image data is acquired using a radiation therapy system having an imaging apparatus. 68. The method of claim 67 wherein the image data is acquired with a radiation beam having a fan-shaped geometry. 69. The method of claim 67 wherein the image data is acquired with a radiation beam having a multi-slice geometry. 70. The method of claim 67 wherein the image data is acquired with a radiation beam having a cone-beam geometry. 71. The method of claim 67 wherein the imaging apparatus uses megavoltage energies. 72. The method of claim 67 wherein the imaging apparatus uses kilovoltage energies. 73. The method of claim 67 wherein the imaging apparatus uses emitted photons. 74. The method of claim 67 wherein the imaging apparatus is a magnetic resonance imaging system. 75. The method of claim 54 wherein the act of delivering radiation to the target region includes the act of delivering photon radiation. 76. The method of claim 54 wherein the act of delivering radiation to the target region includes the act of delivering proton radiation. 77. The method of claim 54 wherein the act of delivering radiation to the target region includes the act of delivering therapeutic particle radiation. 78. The method of claim 54 wherein the act of generating the treatment plan includes the act of incorporating previously delivered dose information. 79. The method of claim 54 wherein the patient remains substantially stationary between the act of acquiring image data from the patient and the act of delivering radiation to the target region. 80. The method of claim 54 wherein the patient lies on a platform, and wherein the patient remains on the platform between the act of acquiring image data from the patient and the act of delivering radiation to the target region. 81. The method of claim 54 wherein the act of generating the treatment plan includes generating a conformal treatment plan and further comprises the act of optimizing the conformal treatment plan. 82. The method of claim 54 wherein the act of generating the treatment plan includes generating an IMRT treatment plan and further comprises the act of optimizing the IMRT treatment plan. 83. The method of claim 54 wherein the treatment plan is used for subsequent treatment fractions. 84. The method of claim 54 wherein the act of generating the treatment plan includes the act of utilizing class solutions. 85. The method of claim 54 wherein the act of generating the treatment plan includes the act of utilizing optimization templates. 86. The method of claim 54 wherein the act of generating the treatment plan includes the act of performing a pre-determined number of iterations. 87. The method of claim 54 further comprising the act of acquiring subsequent image data and the act of generating a subsequent treatment plan based on the subsequently acquired image data. 88. The method of claim 87 wherein the subsequent treatment plan is based at least partially on one or more previous treatment plans. 89. The method of claim 88 wherein the act of generating the treatment plan includes the act of utilizing a biological model. 90. The method of claim 87 wherein the subsequent treatment plan is based at least partially on a previously delivered dose to the patient. 91. The method of claim 90 wherein the previously delivered dose includes an accumulation of a plurality of doses, and wherein the plurality of doses is determined based on a deformation process. 92. The method of claim 54 further comprising the act of generating a subsequent treatment plan, and wherein the subsequent treatment plan includes at least one treatment fraction, wherein the subsequent treatment plan is optimized for at least one treatment fraction. 93. The method of claim 54 wherein the treatment plan includes at least two treatment fractions, and wherein the patient is aligned for delivery of the second treatment fraction using the image data. 94. The method of claim 54 wherein the treatment plan includes at least two treatment fractions, and wherein the patient is positioned for delivery of the second treatment fraction using one of contour information, image information, and dosimetric information. 95. The method of claim 54 further comprising the act of generating a quality assurance plan adapted to validate a dose delivery in a phantom. 96. The method of claim 95 wherein the treatment plan includes a plurality of fractions, and further comprising the act of dividing one of the fractions into a first sub-fraction and a second sub-fraction, and wherein the treatment plan dosimetry is validated after delivery of the first sub-fraction and before completing delivery of the second sub-fraction. 97. The method of claim 54 wherein the radiation source is in communication with an integrated database. 98. The method of claim 54 wherein the radiation source includes a single source point for a radiation beam used in the acquisition of image data from the patient and a radiation beam used in the delivery of radiation to the target region. 99. The method of claim 54 wherein the acquiring, defining, generating an initial contour set, generating a treatment plan, and delivering acts can be completed in less than thirty minutes. 100. The method of claim 54 wherein the radiation source includes a first source point for a radiation beam used in the acquisition of image data from the patient and a second source point for a radiation beam used in the delivery of radiation to the target region. |
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044252951 | abstract | A system for the generation of toroidal current in a plasma which is prepared in a toroidal magnetic field. The system utilizes the injection of high-frequency waves into the plasma by means of waveguides. The wave frequency and polarization are chosen such that when the waveguides are tilted in a predetermined fashion, the wave energy is absorbed preferentially by electrons traveling in one toroidal direction. The absorption of energy in this manner produces a toroidal electric current even when the injected waves themselves do not have substantial toroidal momentum. This current can be continuously maintained at modest cost in power and may be used to confine the plasma. The system can operate efficiently on fusion grade tokamak plasmas. |
claims | 1. A fuel assembly comprising:a bottom nozzle configured to be disposed on a lower plate of a nuclear reactor;a top nozzle including a hold down spring configured to urge the bottom nozzle toward the lower plate;a plurality of control rod guide tubes configured to guide control rods, passed through the top nozzle toward the lower plate; anda thimble screw locked to the bottom nozzle at a seat with a rotation preventive pin to connect the control rod guide tubes to the bottom nozzle, the thimble screw comprisinga drain hole extending in a longitudinal direction from a spot facing hole of the seat to a distal end and configured to receive coolant supplied into the drain hole from the spot facing hole toward the distal end while the nuclear reactor operates and to receive coolant supplied into the drain hole from the distal end toward the spot facing hole during a scram mode, and a coolant collision portion at a drain hole side of the rotation preventing pin against which the coolant flowing from the distal end toward the spot facing hole collides in order to increase pressure drop of the coolant during the scram mode, wherein a collision surface of the coolant collision portion against which the coolant collides forms a flat surface. 2. A fuel assembly, comprising:a bottom nozzle configured to be disposed on a lower plate of a nuclear reactor;a top nozzle including a hold down spring configured to urge the bottom nozzle toward the lower plate;a plurality of control rod guide tubes configured to guide control rods, passed through the top nozzle toward the lower plate; anda thimble screw locked to the bottom nozzle at a seat with a rotation preventive pin to connect the control rod guide tubes to the bottom nozzle, the thimble screw comprisinga drain hole extending in a longitudinal direction from a spot facing hole of the seat to a distal end and configured to receive coolant supplied into the drain hole from the spot facing hole toward the distal end while the nuclear reactor operates and to receive coolant supplied into the drain hole from the distal end toward the spot facing hole during a scram mode, the drain hole having a first large inner diameter portion at a distal end side, a second large inner diameter portion at a seat side, and a small inner diameter portion between the first and the second large inner diameter portions, the spot facing hole is disposed on the seat side, thereby flow rate resistance of the coolant is not influenced while the nuclear reactor operates, and pressure drop for the flow rate of the coolant is increased and decelerating effect of the control rods is improved during the scram mode. 3. A fuel assembly according to claim 2, wherein the thimble screw comprises a coolant collision portion provided at the seat, against which the coolant flowing from the distal end toward the spot facing hole collides to increase pressure drop of the coolant during the scram mode, wherein a collision surface of the coolant collision portion against which the coolant collides forms a flat surface. 4. A fuel assembly, comprising:a bottom nozzle configured to be disposed on a lower plate of a nuclear reactor;a top nozzle including a hold down spring configured to urge the bottom nozzle toward the lower plate;a plurality of control rod guide tubes configured to guide control rods, passed through the top nozzle toward the lower plate; anda thimble screw locked to the bottom nozzle at a seat with a rotation preventive pin to connect the control rod guide tubes to the bottom nozzle, the thimble screw comprisinga drain hole extending in a longitudinal direction from a spot facing hole of the seat to a distal end and configured to receive coolant supplied into the drain hole from the spot facing hole toward the distal end while the nuclear reactor operates and to receive coolant supplied into the drain hole from the distal end toward the spot facing hole during a scram mode, the drain hole having a large inner diameter portion at a distal end side and a small inner diameter portion at a seat side, the spot facing hole disposed on the seat side,wherein the thimble screw comprises a coolant collision portion provided at the seat, against which the coolant flowing from the distal end toward the spot facing hole collides to increase pressure drop of the coolant during the scram mode,wherein a collision surface of the coolant collision portion against which the coolant collides forms a flat surface. |
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abstract | A method for planning a treatment session of a patient and optimizing the treatment time for a treatment using a radiation therapy system includes a radiation therapy unit having a fixed radiation focus point. During an optimization of a treatment plan for a patient, a set of shots to be delivered to a plurality of isocenter positions within a target volume of a patient during a treatment session are determined and a beam-on time for each respective sector and state for each isocenter during which radiation is to be delivered are determined based on the treatment plan. For each isocenter position, sectors and states of respective sector are grouped in accordance predetermined rules with respect to beam-on times for respective state of the sectors, wherein sectors and respective states are aggregated for simultaneous delivery of radiation during a predetermined period of time. |
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summary | ||
description | Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. Referring to FIGS. 1 and 2, a perspective view of a device for storing radioactive material, and an exploded view of a radioactive material container and a radioactive material container outer shield of the storage device according to the present invention are illustrated, respectively. The radioactive material container 10 can be installed in and move out from the radioactive material container outer shield 20 of the storage device 1. As shown in FIG. 3, the radioactive material container 10 includes a lower cup portion 11 and an upper cup portion 12 which can be securely engaged to the lower cup portion 11. Both the lower cup portion 11 and the upper cup portion 12 are preferably constructed of tungsten, but any radiation-resistant material such as lead maybe used. A chamber 13, as shown in FIG. 5, is formed inside the container 10 for storing radioactive material. In the preferred embodiment, the chamber 13 includes an upper and a lower internal cavities 13a and 13b formed in the upper cup portion 12 and the lower cup portion 11, respectively, which is formed while the radioactive material container 10 is assembled by connecting the upper cup portion 12 to the lower cup portion 11. The chamber 13 is syringe-like to receive a syringe holding the radioactive material. Please refer to FIGS. 3 and 5 again. The lower cup portion 11 has a threaded area 14b on the external surface of the open end of the lower cavity 13b. On the other hand, the upper cup portion 12 has a threads 14a on the internal surface of the open end of the upper cavity 13a configured to engage the threads of the threaded area 14b of the lower cavity 13b on the lower cup portion 11. Moreover, an O-ring 14 fits between the lower cup portion 11 and the upper cup portion 12 to provide an air and fluid tight seal. As such, the radioactive material container 10 provides a first shielding structure for storing the radioactive material. Meanwhile, there are cushion members 15a and 15b mounted in both ends of the chamber 13, respectively, that is, the cushion member 15a is mounted in the closed end of the upper cavity 13a, and a cushion member 15b is mounted in the closed end of the lower cavity 13b. The cushion member 15a and 15b can be a sponge to reduce the shock and collision when the storage device 1 is transported. Furthermore, as shown in FIG. 3, in order to conveniently grasp and combine the upper cup portion 12 and the lower cup potion 11, a roughened surface 16a and 16b, such as made of polymer such as ABS or other equivalent material, are formed on a surface thereof, respectively. Referring now to FIGS. 1 and 4, the radioactive material container outer shield 20 includes a base portion 21 and a lid 22 which can be securely covered on the base portion 21. Both the base portion 1 and the lid 12 are also preferably constructed of tungsten, but any radiation-resistant material such as lead maybe used. The outer shield 20 is used as a second shielding structure for receiving the radioactive material container 10. In the preferred embodiment, the base portion 21 has a room 23 to accommodate the radioactive material container 10. It is preferably the radioactive material container 10 precisely fits to the room 23 to prevent from shaking. As shown in FIGS. 4 and 5, a buckle member 25 is pivotedly mounted on an outer surface of the open end of the base portion 21, and the lid 22 is pivotedly mounted to the base portion 21 opposite to the buckle member 25. Moreover, the lid 22 has a resilient snap 26 to snap on the buckle member 25 after the lid 22 is covered on the base portion 21, and buckled by the buckle member 25. Similarly, an O-ring 24 is used to provide a seal between the open end of the base portion 21 and the lid 22. Such that, the room 23 in the radioactive material outer shield 20 can be sealed to provide second shielding protection with the radioactive material container 10 nested therein. Referring now to FIGS. 2, 5 and 6, the storage device 1 of the present invention further includes a ring member 17 pivotedly connected to the top end of the radioactive material container 10. The ring member 17 can stand out of the base portion 21 when the lid 22 is opened. Therefore, a tool 30, such as a container hook, can be used to hook the ring member 17 to pull out of the container 10 from the outer shield 20. As such, it reduces the chances for the operating personnel to contact the container 10. Please refer back to FIGS. 4 and 5 again, in this preferred embodiment, a magnetic mechanism is used to raise the ring member 17. A magnetic member 27 is mounted on the bottom surface of the lid 22 while the ring member 17 is made by the material which is attracted by the magnetic member 27. When the radioactive material container 10 is put in the outer shield 20, the ring member 17 is rested on the top surface of the upper cup portion 12. Meanwhile, when the lid 22 is covered on the base 21, the magnetic member 27 is faced closely to the ring member 17. As shown in FIG. 6, when the lid is opened, due to the magnetism, the ring member 17 is attracted by the magnetic member 27 to stand out of the base portion 21. Referring to FIG. 7, a tool 30 is used to hook the ring member 17 to pull out of the radioactive material container 10. As such, a proper solution is provided to prevent the operating personnel from contacting the container 10. Furthermore, an elastic mechanism can also be used to raise the ring member 17. An elastic member (not shown) may be furnished between the upper cup portion 12 and the ring member 17. Therefore, when the lid 21 is opened, the ring member 17 is raised by the elastic member. Thereby, the device for storing radioactive material with secure seal and firmly lock is obtained according the above-mentioned description. Finally, as shown in FIGS. 8 and 9, for example, different kind of shipping apparatuses 2 are provided to transport the storage device 1. As shown in FIG. 8, the shipping apparatus 2 is a radioactive material shipping bag with radiation-resistant ability. The shipping apparatus 2 includes a bag body 40, a retractable handle 50 extended upwardly from the bag body 40 for the operating personnel keeping away from the storage device 1 to safely move the bag body 40. There are a plurality of wheels 60 mounted under the bag body 40 for convenient conveyance. Moreover, the bag body 40 includes a protective foam 41 made of polymer such as EVA foam or the equivalent material, surrounding a hollow space 42 inside the bag body 40 for holding the storage device 1. Therefore, the storage device 1 of the present invention can be transported more safely. Instead, as shown in FIG. 9, the shipping apparatus 2 includes only a bag body 40xe2x80x2 and two handles 50xe2x80x2 fixedly furnished on the bag body 40xe2x80x2 can also provide the same function to transport the storage device 1. This disclosure provides exemplary embodiments of the present invention. The scope of this disclosure is not limited by these exemplary embodiments. Numerous variations, whether explicitly provided for by the specification or implied by the specification, such as variations in shape, structure, dimension, type of material or manufacturing process may be implemented by one of skill in the art in view of this disclosure. |
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description | 1. Field of the Invention This invention relates to a technique for offsetting the deflection of an ion beam due to a geomagnetic field or a magnetic field intruding into an ion optics from another device and thus forming the ion beam spot on a sample at substantially the same position as if there is no magnetic field and a technique for avoiding the split of a beam spot which otherwise might occur in the case where the ion beam contains a plurality of types of isotopes. 2. Description of the Related Art A FIB (focused ion beam) apparatus is used in practical applications to microprocess a sample or to observe an image of the sample by radiating a finely focused ion beam on the sample. The ion beam is deflected by the Lorentz force in the presence of a magnetic field on the optical axis. The accelerating voltage of the FIB apparatus is normally about several tens of kV, and therefore the beam spot may be displace several tens of μm or more by the geomagnetic field. Further, the normally used ion specie Ga Ga contains two types of isotopes Ga69 and Ga71 deflected to different degrees by a magnetic field, thereby posing the problem that the beam is split into two. The ion beam is split also in the case where ions form a cluster. For the beam spot displacement of about several tens of μm, the distance between the two types of ion beams split may reach about 1 μm depending on the difference of the mass-to-charge ratio. It is essential to avoid or suppress this phenomenon for the FIB apparatus which is used for the purpose of microprocessing on the order of nanometer. The simplest method of excluding the magnetic field on the optical axis is to magnetically shield the housing by covering it with a magnetic material as in the prior art. JP-A-11-329318 discloses a technique for magnetically shielding also the forward end portion of the FIB apparatus. It is difficult, however, to magnetically shield a sample including the neighborhood thereof completely. The sample and the neighborhood thereof could be magnetically shielded almost completely if the whole apparatus is covered with a magnetic shield. It is often desired to form a hole in the magnetic shield, and in such a case, the magnetic field intrudes by way of the hole. The FIB apparatus normally comprises an electric deflector for radiating the ion beam at the desired position on a sample. Although the displacement of the ion beam spot on the sample due to a magnetic field can be canceled using the electric deflector, it is impossible to prevent the separation of isotopes at the same time. The Wien filter is another means known to deflect the ion beam positively. However, this filter is used rather the purpose of strongly separating isotopes and removing the unnecessary isotope components by bombarding a wall (JP-A-7-296756). Therefore, the exit of the ion beam is very narrow, and in the presence of an external magnetic field, it is difficult for the ion beam to pass through the exit. In view of this, demand has arisen for a technique by which neither the ion beam spot is displaced nor isotopes separated even in the presence of a magnetic field on the optical axis of the ion beam. This problem is more serious for the FIB-SEM comprising a FIB column and a SEM column combined with each other. The FIB-SEM has recently began to find practical applications as a combination of the observation SEM (scanning electron microscope) and the FIB apparatus to observe a sample processed by the FIB apparatus with a higher resolution. The SEM, which normally has an electromagnet as an objective lens, is required to use the type of a lens called the semi-in or snorkel lens leaking a magnetic field toward the sample to achieve a higher resolution. This magnetic field intrudes into an area on the optical axis of the FIB apparatus and strongly deflects the ion beam. In the case where the ion beam is configured of a plurality of types of beams having different mass-to-charge ratios, therefore, these beams are split from each other. In view of the fact that the ion beam is required to be radiated on a sample in the vicinity of the objective lens of the SEM, on the other hand, the optical axis of the ion beam cannot be magnetically shielded sufficiently. Another problem is that the arrangement of a magnetic shield in the vicinity of the SEM objective lens disturbs the magnetic field of the SEM objective lens and adversely affects the resolution of the SEM. No technique has been disclosed to solve this problem. Under the circumstances, a FIB-SEM application using the SEM leaking the magnetic field to the neighborhood of a sample uses a method in which the magnetic field of the objective lens of the SEM is suspended during the microprocessing of the sample by the FIB apparatus while the FIB apparatus is stopped during the observation of the sample under the SEM. Even after the exciting current of the objective lens of the SEM is stopped, however, the magnetic field remains. This residual magnetic field changes with time, thereby posing the problem that the ion beam spot also moves with time. To avoid this problem, JP-A-11-329320 discloses a technique in which a demagnetization coil to remove the residual magnetic field is arranged in the neighborhood of the objective lens of the SEM. This method is bothersome to execute, however, in view of the need of demagnetization of the SEM objective lens each time the operation is switched from the SEM to the FIB apparatus. In microprocessing a sample by the FIB apparatus while at the same time observing the sample under the SEM, an out lens not leaking the magnetic field is conventionally used as an objective lens of the SEM. With the increase in demand for a higher resolution of the SEM, however, the use of an objective lens of semi-in type has become unavoidable. Thus, a technique is in demand to realize the FIB apparatus and the FIB-SEM in which neither isotopes of the ion beams are not separated nor the position of the ion beam spot is not changed on the sample against the existence or a change of a magnetic field on the optical axis of the ion beam. In view of the present situation of the FIB apparatus described above, it is an object of this invention to provide a focused ion beam apparatus and a focused ion beam irradiation method in which even in the case where a magnetic field exists or changes on the optical axis of an ion beam, the isotopes of the ion beam are not separated on the sample and the ion beam is focused at the beam spot position in the same manner as if a magnetic field is absent, and in the case where the FIB apparatus is combined with a SEM to make up a FIB-SEM, the sample can be microprocessed by the FIB apparatus while at the same time making it possible to observe a sample image with a high resolution under the SEM. In order to achieve this object, an optics is configured that an area where the components of the magnetic field perpendicular to the optical axis of the ion beam assume opposite directions exists on the optical axis of the ion beam, with the result that the beam spot is located on the same position on the sample as if a magnetic field is absent. With this configuration, even though a plurality of types of isotopes contained in the ion beam are separated and proceed along different optical paths, the ion beams of all the isotopes are focused again at the same beam spot position. Especially in the case of the FIB-SEM, the primary source of the magnetic field is the objective lens of the SEM. In the narrow area in the neighborhood of the optical axis of the SEM, a downward (or upward) strong magnetic field exists, while an upward (or downward) weak magnetic field is exerted in the wide area outside the objective lens. The above mentioned effect can be produced by configuring the ion beam optics to pass through the two magnetic fields in an appropriate ratio. For fine adjustment of the ion beam spot position, the desired magnetic field should be positively generated from a canceling magnetic field generating unit arranged on the optical beam of the ion beam. As long as the canceling magnetic field has a magnitude proportional to the external magnetic fields (including the magnetic field from the SEM objective lens of the FIB-SEM), the above-mentioned effect can be maintained against any variation in the external magnetic fields. According to this invention, there are provided a FIB apparatus and a FIB irradiation method in which even in the case where a magnetic field exists on the optical axis of the ion beam and undergoes a variation, the isotopes of the ion beam are not separated on a sample and the ion beam is focused at the same beam spot position as if in the absence of the magnetic field. Further, in the FIB-SEM configuration of the FIB apparatus and the SEM combined, the microprocessing of the sample by the FIB apparatus and the sample observation with high resolution by the SEM are realized at the same time. Other objects, features and advantages of the invention will become apparent from the following description of the embodiments of the invention taken in conjunction with the accompanying drawings. Embodiments of the invention are explained below with reference to the drawings. In the drawings, similar component parts are designated by the same reference numeral and not described again. FIG. 1 is a schematic diagram showing an example of a configuration of a FIB-SEM according to the invention. The Ga ions released from a Ga liquid metal ion source 1 are accelerated by the electric field generated by an accelerating electrode 2 and formed into, for example, a Ga ion beam 3 having a kinetic energy of, say, 30 keV. The ion beam is focused at a crossover 5 by an electric condenser lens 4 (or without any cross over, focused into a substantially parallel state), and further focused on a sample 7 by an electric objective lens 6. The Ga ion beam 3 is composed of two types of isotopes, Ga69 and Ga71 having contents in the ratio of 6 to 4. The secondary electrons generated from the sample 7 irradiated with the ion beam are detected by a detector not shown, and the image of the sample can thus be observed. A SEM 17 is used, however, for observing the image of the sample with high resolution. The electron beam 11 of the SEM 17 is generated from a cathode 21, and after passing through an electro-optics including an accelerating electrode and a condenser lens not shown, focused on the sample by the objective lens 8 of the SEM, so that secondary electrons are generated from the surface of the sample. The secondary electrons, passing by the optical axis of the SEM 17, enter an ExB 22, and after being deflected by the magnetic and electric fields of the ExB 22, detected by a secondary electron detector 23. The electric and magnetic fields of the ExB 22 are adjusted to offset the effects thereof not to affect the electron beam 11 from the cathode. The optical axis of the ion beam 3 and the optical axis of the electron beam 11 of the SEM cross each other substantially at a single point on the sample 7. Therefore, the working area can be observed under the SEM while at the same time microprocessing the sample 7 by the ion beam 3. The wording “substantially at a single point” is indicative of the fact that the spot of the ion beam 3 on the sample 7 is so near as to be included in the visual field of the SEM 17, i.e. the scanning range of the electron beam 11. This distance is not more than 1 μm for the observation under the SEM with high resolution. The SEM objective lens 8 is called a semi-in lens or snorkel lens by which the main lens surface is brought in proximity to the sample and the magnetic field is positively distributed toward the sample to secure a high resolution. Therefore, the magnetic field 25 generated from the SEM objective lens 8 is distributed on the optical axis of the ion beam 3. The components of this magnetic field perpendicular to the optical axis of the ion beam 3 deflect the ion beam 3 by the Lorentz force. These magnetic field components in the neighborhood of the SEM objective lens 8 and the other areas are directed oppositely, as shown in FIG. 2. In FIG. 2, the abscissa represents the coordinate on the optical axis of the ion beam with the ion beam spot position on the sample 7 as an origin. The area of the ion beam optical axis nearer to the ion source 1 is covered with a magnetic shield 9 and therefore has substantially no magnetic field. The ion beam 3 entering an area not covered by the magnetic shield 9 senses a magnetic field. As a result, the ion beam is deflected by the Lorentz force in the direction perpendicular to the page away from the reader. The ion beam 3 further proceeds and reaching the neighborhood of the SEM objective lens 8, senses a magnetic field in the opposite direction as understood from FIG. 2. As a result, the ion beam 3 is subjected to the Lorentz force perpendicular to the page toward the reader, and being deflected in that direction, reaches the surface of the sample 7. At this time, the ion beam spot is located almost but not exactly at the same position position as in the absence of the magnetic field. The area of the ion beam optics covered with the magnetic shield 9 is determined as near as possible to the position lacking the magnetic field. FIG. 3 shows the ion beam track in such a case. Now, the displacement of the ion beam spot on the sample resulting from the ion beam deflection by the magnetic field described above is expressed by an equation. The equation of ion motion is given as shown in (1) below. ⅆ 2 r ⅆ t 2 = q m ( v × B ( r ) + E ( r ) ) ( 1 ) In this equation, r is a position vector of ions, v a rate vector of ions, B(r), E(r) a magnetic field vector and an electric field vector, respectively, m an ion mass, q an ion charge and t the time. The coordinate system used in this case is a right-handed system having an origin at the beam spot position on the sample in the absence of a magnetic field, the z axis along the ion beam optical axis and the x axis perpendicular to the magnetic field, i.e. in the direction of beam deflection. The direction of the magnetic field on the optical axis is contained in the yz plane. In equation (1), E(r) corresponds to the electric field of the objective lens 6 of the ion beam optics. As compared with the velocity vz along the optical axis, vx, vy are negligibly small. Equation (1) for the x component, therefore, is written as shown below. ⅆ 2 x ⅆ t 2 = e m ( B y ( z ) v z ( z ) + E x ( z ) ) ( 2 ) The equation for y direction is the same as in the absence of a magnetic field and not described. As for the z direction, the following equation equivalent to the equation of motion is conveniently used. This indicates the energy conservation rule. v z ( z ) = 2 e ( V acc - ϕ ( z ) ) m ( 3 ) where Vacc is the accelerating voltage, and Φ (z) the electric potential for z. The left side of equation (2) is modified to obtain the following equation. ⅆ 2 x ⅆ t 2 = ⅆ z ⅆ t ⅆ ⅆ z ( ⅆ z ⅆ t ⅆ x ⅆ z ) = v ( z ) ⅆ ⅆ z ( v ( z ) ⅆ x ⅆ z ) ( 4 ) Equations (4) and (3) are substituted into equation (2) and integrated. Then, the displacement Δx of the beam spot on the sample is obtained. The distance from the point of emission of the ion beam to the sample is designated as L. The emission point may be anywhere on the optical axis not covered by the magnetic field. Δ x = e m ∫ L 0 ⅆ z 1 v ( z 1 ) ∫ L z 1 B y ( z ) v z ( z ) + E x ( z ) v ( z ) ⅆ z = e m ∫ L 0 m 2 e ( V acc - ϕ ( z 1 ) ) ⅆ z 1 ∫ L z 1 ( B y ( z ) + E x ( z ) m 2 e ( V acc - ϕ ( z ) ) ) ⅆ z = e m ∫ L 0 ⅆ z 1 2 e ( V acc - ϕ ( z 1 ) ) ∫ L z 1 B y ( z ) ⅆ z + 1 2 ∫ L 0 1 ( V acc - ϕ ( z 1 ) ) ⅆ z 1 ∫ L z 1 ( E x ( z ) ( V acc - ϕ ( z ) ) ) ⅆ z ( 5 ) In equation (5), the second term contains neither the mass of ions nor a magnetic field. In other words, this equation corresponds to the beam in the absence of a magnetic field and represents the displacement due to the objective lens of the FIB. Since Ex is zero for the beam passing through the optical axis, the beam passes through the origin. The first term depends on the magnetic field. This term is inversely proportional to √m and therefore corresponds to the separation of isotopes by the magnetic field. Let Δm be the mass difference of the isotopes, and the isotope separation width δ is given by equation (6). δ = Δ x 2 Δ m m ( 6 ) The position of the end surface of the magnetic shield 9 nearer to the sample is determined at a value equal to L minimizing the first term of equation (5). The magnetic field By(z) can be adjusted any time in such a manner that the integration of the first term is complete zero by superposing an appropriate canceling magnetic field on the leakage magnetic field from the SEM objective lens 8. By generating this canceling magnetic field on the optical axis, the first term of equation (5) is deleted. Then, the effect of the magnetic field can be completely eliminated within the range of first order approximation to the beam spot position on the sample. In other words, equation (5) indicates that the deflection of the beam and the separation of isotopes due to the magnetic field can be offset with each other. Based on this idea, this embodiment uses a canceling magnetic field generator 10 to assure complete coincidence of the ion beam spot position with the position associated with the absence of the magnetic field. The canceling magnetic field generator 10, as shown in FIGS. 4A, 4B, is configured of a pair of opposed coils 15 and a magnetic yoke 16 of permalloy. This magnetic yoke 16 has the function as a magnetic shield for both generating a canceling magnetic field efficiently on the ion beam optical axis and suppressing the leakage magnetic field out of the coils 15 at the same time. The material of the magnetic yoke 16 is not limited to permalloy but may be any magnetic material such as pure iron or permendule having a high permeability and a low coercive force. The higher the permeability, the smaller the external leakage magnetic field can be. The canceling magnetic field generator 10 has a central beam path arranged in alignment with the ion beam optical axis. The beam path of the canceling magnetic field generator 10 has a sufficient diameter to pass the whole ion beam passed through the condenser lens 4. The canceling magnetic field 26 is generated on the ion beam optical axis 3 in the direction parallel to the page and perpendicular to the ion beam optical axis 3. In this way, the Lorentz force is exerted on the ion beam in the direction perpendicular to the page and the optical axis. This direction is parallel to the Lorentz force due to the magnetic field from the SEM objective lens 8, and therefore by appropriately adjusting the direction and magnitude of the canceling magnetic field, the position of the ion beam spot on the sample 7 can be completely rendered coincident with the position in the absence of a magnetic field. Arithmetically, the first term of equation (5) can be reduced to zero. The beam spot is not necessarily circular in shape. This theory according to the invention effectively holds even in the case where the cross section of the beam is elliptic or linear under the effect of stigmatic aberration or the like. The term “beam spot” referred to in this specification can assume any shape. The canceling magnetic field generator 10, though adapted to be located at any point on the ion beam optical axis, is better located at such a distance from the sample 7 as not to disturb the magnetic field of the SEM objective lens 8. According to this embodiment, the canceling magnetic field generator 10 is arranged at the position 100 mm from the beam spot point on the sample 7. Also, the canceling magnetic field is effective over an area 10 mm long. FIGS. 4A, 4B show a pair of coils 15. Nevertheless, two or more pairs of coils may be used. In the case where two or more pairs of coils are used, the direction as well as the magnitude of the canceling magnetic field can be conveniently set freely. FIG. 4C corresponding to FIG. 4B shows a case having two pairs of coils. FIG. 5 shows the state of the ion beam tracks in the neighborhood of the sample with the magnetic field of the canceling magnetic field generator 10 changed. The solid line indicates the track of Ga69 and the dashed line that of Ga71. The ordinate has an origin at the ion beam spot position in the absence of a magnetic field. The abscissa represents the distance from the ion beam spot position on the sample along the ion beam optical axis. In the presence of a magnetic field, the ion beam is split according to the mass-to-charge ratio of the ions, while the split width on the sample is proportional to the displacement of the ion beam spot from the origin on the sample. As understood from FIG. 5, therefore, the smaller the displacement of the ion beam spot from the origin, the smaller the width by which two types of isotopes are separated from each other. According to this embodiment, the ion beam passes through the origin while the width by which the isotopes are separated is about zero in the case where the magnetic flux density of the canceling magnetic field is 1.96 Gauss. In this case, the angle of incidence of the ion beam 3 to the sample 7 is about 1 mrad, and the maximum displacement of the ion beam 3 from the optical axis is not more than 6 μm. Thus, the effect on the performance such as the aberration of the ion beam optics can be neglected. Once the ion beam is deviated considerably from the center of the objective lens 6, the resolution of the focused ion beam is deteriorated as the result of the beam spot being increased due to the off-axis aberrations of the objective lens 6. In such a case, as shown in FIG. 6, the provision of two serial stages of the canceling magnetic field generator 10 makes it possible for the ion beam 3 to pass through the center of the objective lens 6 without splitting the ion beam spot. Also, as shown in FIG. 7, with a single stage of the canceling magnetic field generator 10, the ion beam 3 may be adjusted to pass through the center of the objective lens 6 using an electric deflector 24. The change in the ion beam track by the electric deflector 24 is not dependent on the mass-to-charge ratio of ions, and therefore the ion beam spot is not split by the electric deflector 24. Also in this case, therefore, the ion beam 3 can be passed through the center of the objective lens 6 without splitting the ion beam spot. The embodiment described above refers to a case in which the ion beam contains the ion species of Ga69 and Ga71. Nevertheless, the ion species contained in the ion beam are not limited to Ga69 and Ga71. A well-known ion specie other than Ga is Sn. In this case, ions such as Sn+, Sn2+ and Sn2+ are generated at the same time. A plurality of ion species having different mass-to-charge ratios are contained not only in the isotope but also in the allotrope. Also, ions of different valences and a mixture of completely different materials are available. According to this invention, in all of these cases, like in this embodiment, the ion beam spot can be formed without being split at the same position on the sample as in the absence of a magnetic field. FIG. 8 is a schematic diagram showing another example of a configuration of the FIB-SEM according to the invention. Normally, the excitation of the objective lens 8 of the SEM 11 is required to be changed frequently to change the focal length or the accelerating voltage. In line with this, the magnitude of the magnetic field on the ion beam optical axis of the FIB apparatus is changed, with the result that the ion beam spot on the sample 7 is displaced and in proportion to this displacement, the isotopes are separated. To solve the aforementioned problem, this embodiment includes a canceling magnetic field control unit 12. The canceling magnetic field control unit 12, upon receipt of a signal proportional to the exciting current of the SEM objective lens 8 from a SEM objective lens exciting current control unit 13, supplies the coil of the canceling magnetic field generator 10 with a current proportional to the particular signal. The displacement of the ion beam spot on the sample 7 is proportional to the magnitude of the magnetic field on the ion beam optical axis 3. In the configuration according to this embodiment, therefore, the ion beam spot is always maintained at the origin, i.e. at the ion beam spot position in the absence of a magnetic field, and the isotopes are not separated even in the case where the magnetic field generated by the SEM objective lens 8 is changed considerably. FIG. 9 is a schematic diagram showing another example of a configuration of the FIB-SEM according to the invention. In the case where an external magnetic field for deflecting the ion beam 3 exists in addition to the magnetic field generated by the SEM objective lens 8 and changes in magnitude, the actually existing magnetic fields are effectively measured. According to this embodiment, as shown in FIG. 9, an output of a magnetic field sensor 14 is input to the canceling magnetic field control unit 12. Although a Hall element is used as the magnetic field sensor 14 in this embodiment, any other element capable of measuring the magnetic field such as a magnetoresistive element can be used. In the case where no magnetic field is generated by the SEM objective lens 8, the canceling magnetic field control unit 12 supplies the coils of the canceling magnetic field generator 10 with a current proportional to the magnetic field measured by the magnetic field sensor 14. Normally, the relative spatial distribution of the magnetic field can be considered constant, and only the intensity factor thereof changes uniformly. It is therefore sufficient to measure the intensity of the magnetic field only in one arbitrary direction at an arbitrary point in a sample room. To improve the measurement sensitivity, however, the position and direction of measurement should be selected where the intensity of the magnetic field to be measured is as high as possible. In the presence of a plurality of sources of the magnetic field, the relative spatial distribution of the magnetic field in the sample room may also undergo a change. In such a case, the outputs of a plurality of magnetic field sensors are input to the canceling magnetic field control unit 12, which supplies the coils of the canceling magnetic field generator 12 with a current proportional to the linear combination of a plurality of inputs. As a result, a highly accurate correction is made possible even in the case where the relative spatial distribution of the magnetic field undergoes a change. In the case where the magnetic field generated by the SEM objective lens 8 also undergoes a change, the canceling magnetic field control unit 12 supplies the coils of the canceling magnetic field generator 10 with a current corresponding to a linear coupling, at an appropriate ratio, between an input signal proportional to the exciting current of the SEM objective lens 8 from the SEM objective lens exciting current control unit 13 and the input signal from the magnetic field sensor 14. The displacement of the ion beam spot on the sample 7 is proportional to the magnitude of the magnetic field on the ion beam optical axis 3. With the configuration according to this embodiment, therefore, the ion beam spot is always maintained at the origin, i.e. at the ion beam spot position in the absence of a magnetic field and the isotopes are not separated even in the case where at least one of the magnetic field generated by the SEM objective lens 8 and an external magnetic field undergoes a change. FIG. 10 is a schematic diagram showing still another example of a configuration of the FIB-SEM according to the invention. The optical axis of the electron beam 11 of the SEM 17 and the optical axis of the ion beam 3 cross each other substantially perpendicularly to each other at about a single point 20 of the sample 7, and an electron detector 19 is arranged on the optical axis of the electron beam 11 of the SEM 17 on the side of the crossing 20 far from the SEM objective lens 8. According to this embodiment, the SEM is used as a scanning transmission electron microscope (STEM). The desired portion for observation of the sample 7 under the STEM and the surrounding portion are processed by FIB in such a manner that the particular desired portion remains as a thin film 7a. Also, the optical path of the electron beam 11 entering the thin film sample 7a and the transmitted electron beam 18 transmitted through the thin film sample 7a and proceeds toward the electron detector 19 are secured by FIB processing. The transmitted electron beam 18 includes a small angle scattering transmitted electron beam 18a proceeding in substantially the same direction as the the incident beam and a wide angle scattering transmitted beam 18b considerably displaced out of the direction of incidence, each being detected by electron detectors 19a and 19b, respectively. A scanning image is formed from the signal of each detector as a brightness signal in synchronism with the scanning of the incident electrons. Then, a bright field image and a dark field image are obtained. The scattering angle distribution of the transmitted electrons is greatly dependent on the atom number of the sample, so that the larger the atom number, the larger the degree of wide angle scattering. Therefore, an image having a strong atom number contrast is obtained. The feature of this embodiment lies in that the electron beam axis and the ion beam axis are arranged substantially at right angles to each other, so that the thin film sample 7a being processed by the FIB can be observed as a STEM image on a monitor without moving the sample 7. As a result, the invention exhibits an especially great effect for an application of observation of the pinpoint processing to analyze a defect of a device or the like. The sample 7 may be a small piece separated in advance from a wafer or the like, or a micro sample collected by the microsampling process from a wafer in the same sample room. The deflection of the ion beam 3 or the separation of the isotopes on the sample due to the leakage magnetic field affecting the sample 7 from the objective lens 8 of the SEM 17 can be obviated by the canceling magnetic field generator 10. The SEM objective lens 8, therefore, can be arranged with the forward end thereof as near as 4 to 8 mm from the sample observation point. Consequently, the high-resolution SEM/STEM observation is made possible. It should be further understood by those skilled in the art that although the foregoing description has been made on embodiments of the invention, the invention is not limited thereto and various changes and modifications may be made without departing from the spirit of the invention and the scope of the appended claims. |
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abstract | A method of resetting a substrate processing apparatus having a chamber which is capable of carrying out abnormality judgment on the substrate processing apparatus accurately without causing a decrease in the utilization ratio of the substrate processing apparatus. The chamber is evacuated. A temperature in the chamber is set. Whether or not there is an abnormality in the chamber is judged. An atmosphere in the chamber is stabilized so as to conform to predetermined processing conditions. At least one selected from data that change in response to a change in a state inside the chamber is measured. The measured data is compared with reference data that corresponds to the measured data for a normal state in the chamber. |
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description | This application claims priority to U.S. Patent Application Ser. No. 61/897,271 filed Oct. 30, 2013 entitled “System And Method For Determining The Radiological Composition of Material Layers Within a Conduit” by Frederic J. Mis of Webster, N.Y., the entire disclosure of which is incorporated herein by reference. 1. Field of the Invention The present invention relates generally to measurement equipment and methods, and more particularly to a System and Method For Determining The Radiological Composition of Material Layers Within a Conduit. 2. Description of the Related Art Determination of the radiological contamination layer within a conduit such as a light water reactor pipe in a nuclear power plant provides proper decision making regarding chemistry regimes to best minimize the radiological transportation of corrosion products and activation products. Corrosion products such as Co-58 and Co-60, and some fission products such as Cs-134 and Cs-137, are the primary causes of radiation exposure to plant workers during reactor maintenance. In addition, excessive corrosion on valves reduces their operational effectiveness. Once the make-up of the corrosion layer is understood, changes in plant water pH, clean up system alternatives, or operating temperatures may be made to reduce the continuous build up of corrosion products. Unfortunately, techniques and equipment currently used to measure the radiological contamination layer within pipes in a nuclear power plant are large, bulky, and difficult to maneuver into the sometimes tight, inaccessible, or elevated spaces within a nuclear power plant. What is needed is a measurement device and associated methods that is compact, lightweight, easy to operate, and provides quick and accurate readings of the radiological contamination layer within the conduit, pipe, or vessel. It is thus an object of the present invention to provide a System and Method For Determining The Radiological Composition of Material Layers Within a Conduit such as a pipe or a vessel. Other objects of the present invention include, but are not limited to, determining vessel thickness, occlusion, scarring, or the like in human or animal bodies. These and other objects of the present invention are not to be considered comprehensive or exhaustive, but rather, exemplary of objects that may be ascertained after reading this specification with the accompanying drawings and claims. In accordance with the present invention, there is provided a system for determining the radiological composition of material layers within a conduit comprising a probe contained within a collimator; a spectrometer operatively connected to the probe; a phantom setup comprising a vessel containing a test standard, a plurality of removable plates, and a collimator probe attachment point; and a semi-logarithmic plot of spectrometer readings taken with various quantities of removable plates for comparison with field readings. Additionally, a source for field readings and a method for comparing the semi-logarithmic plot of spectrometer readings with the field readings are provided. The foregoing paragraph has been provided by way of introduction, and is not intended to limit the scope of the invention as described by this specification and the attached drawings and claims. The present invention will be described in connection with a preferred embodiment, however, it will be understood that there is no intent to limit the invention to the embodiment described. On the contrary, the intent is to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by this specification, claims and drawings attached hereto. The use of gamma spectroscopy for measuring the radiological composition of material layers within a pipe is incomplete at best. While the thickness of the pipe and associated nuclear insulation is known, the composition and radioactivity of the corrosion layer within the pipe is not. A method and system to create and use a novel phantom setup in conjunction with a spectrometer provides the ability to determine the radiological composition of the corrosion layers within a pipe, something that was heretofore not attainable with spectrometers alone. The System and Method For Determining The Radiological Composition of Material Layers Within a Conduit uses actual radioisotopes in known activity deposition, using NIST traceable activities, uniformly distributed in an extremely thin layer within a planar phantom. Steel plates are then added to create thicknesses that mimic the standard pipe thicknesses found in light water reactors. These thicknesses include ⅜ inch, 1.25 inch, 2.25 inch, and 2.75 inch. In addition, a layer of nuclear insulation is added to mimic those instances when measurements are made with insulation remaining on the pipe. The measurements that are taken are plotted using a semi-logarithmic scale, and are a straight line. The slope of the resulting line becomes a calibration factor which, based on the radioisotopes used, reflects the conditions within an enclosed system. This system is the first modeled, calibration system which provides actual attenuation, build up and scatter conditions that would affect real world systems. To take measurements in both the calibration environment using a phantom setup and in the field, a collimator-probe arrangement is disclosed. FIGS. 1-6 depict such a collimator probe of the present invention. FIG. 1 is a perspective view of the collimator-probe 100 of the present invention. A shielded housing 101 can be seen, which serves as a collimator having an opening to direct detected radiation towards a sensing face of a probe contained within the collimator. The shielded housing 101 may, in some embodiments of the present invention, be generally cylindrical. An example of suitable dimensions for a generally cylindrical shielded housing 101 is a cylinder that is approximately 8 centimeters tall with a diameter of 6 centimeters. The wall thickness of this exemplary cylinder is approximately 1.4 centimeters. The shielded housing 101 is made from a high density material such as lead, tungsten, depleted uranium, or the like to provide proper shielding. The shielded housing 101 is also covered with a material such as copper to allow for rapid decontamination. Such a covering is made by electroplating, forming of a suitable foil around the shielded housing, painting, or the like. Both the inside and the outside of the shielded housing 101 are covered with such a material. The shielded housing 101 may be cast, molded, machined, or otherwise formed into a generally hollow structure such as a cylinder that is capable of containing a probe, such as the probe 203 depicted in FIG. 2. In addition, a soft material such as a plastic sponge material may line the inside of the shielded housing 101 in order to secure the probe 203 (see FIG. 2) and keep it centered within the shielded housing 101. A removable cover 103 is fitted to the shielded housing 101 to allow for access to the probe contained within. The removable cover 103 may be made from a similar high density material as that which the shielded housing 101 is made from. Lead, tungsten or depleted uranium, for example, are suitable high density materials. The removable cover 103 is also covered with a material such as copper or a layer of tin and copper to allow for rapid decontamination. Such a covering is made by electroplating, forming of a suitable foil around the shielded housing, painting, or the like. The removable cover 103 may be cast, molded, machined, or otherwise formed. In some embodiments of the present invention, the removable cover 103 has a feature such as a recessed or beveled circumference that joins with a mating surface of the shielded housing 101 for proper retention thereof. Mating features between the removable cover 103 and the shielded housing 101 may also include threads, tabs, slots, pins, posts, sockets, and the like. The removable cover 103 is of a geometry that matches with the geometry of the shielded housing, for example circular. The removable cover 103 also has an opening 111 such as a circular opening that contains a spacer 105 and a grid 107. The opening 111 is sized to accommodate the face of the probe 203 (see FIG. 2), and may, in one embodiment of the present invention, be approximately 2.4 centimeters in diameter. The probe 203 (see FIG. 2) sits recessed in the opening 111, and may, for example, sit approximately 2 centimeters inward. The spacer 105 is fitted to the shielded housing 101 to keep the probe contained within the shielded housing 101 a constant distance from the opening 111 in the removable cover 103. The spacer may, in one embodiment of the present invention, be an open cylinder or otherwise annular in geometry. Fitted within or proximate to the spacer 105 is a grid 107. The grid 107 is made from a high density material such as lead, tungsten or depleted uranium, and prevents low energy lateral photons from hitting the face of the probe, which would result in incorrect readings. An example of a suitable grid 107 is a three by three matrix of lead plates where each plate is 1/16 inch thick and 1 centimeter deep. The lead plates are aligned to create a grid 107 such as that depicted in FIG. 2 where the grid 107 comprises a plurality of rectangular openings. The grid 107 may also be cast, machined, or otherwise fabricated such that a plurality of openings are created. The openings may be rectangular, square, circular, or the like. The spacer 105 and the grid 107 are retained in the opening 111 by use of glue, adhesives, solder, retainer rings, clips, or the like. FIG. 2 depicts an exploded view of the collimator-probe of the present invention. The shielded housing 101 can be seen along with the removable cover 103, and the spacer 105 and grid 107. Also seen in FIG. 2 is the probe retainer 201 that may be generally cylindrical in shape and made from a soft material such as a low density polyethylene foam or the like. A low density material provides a low attenuation coefficient and is thus desirable to avoid erroneous readings. In some embodiments of the present invention, the probe retainer 201 is secured only by friction, without the use of glue. Within the probe retainer 201 is the probe 203. A suitable probe is a cadmium Zinc Telluride (CZT) probe such as those made by Canberra of Meriden, Conn., USA. The CZT probes made by Canberra may also be used with their Inspector 1000 display. Various size probes are available based on the energy range of interest. A 500 mm2 probe adequately monitors a maximum dose rate of 200 mrem/hr. A 60 mm3 probe has an upper range of 1,000 mrem/hr. The probe 203 is positioned such that its sensing surface is facing outward through the opening 111. FIG. 3 is a front plan view of the collimator-probe of the present invention. The grid 107 can be seen with the sensing surface of the probe behind the grid 107. FIG. 4 is a cross sectional view of the collimator-probe of the present invention taken along line A-A of FIG. 3. The probe retainer 201 can be seen with the probe 203 centered there within. The spacer 105 can also be seen along with the shielded housing 101 and the removable cover 103. The removable cover 103 in the embodiment depicted in FIG. 4 has a flange that protrudes perpendicular to the inner surface of the removable cover 103 and is circumferential to the opening that contains the spacer 105 and grid 107, thus providing as secure fit to the shielded housing 101. FIG. 5 is an exploded cross sectional view of the collimator-probe of the present invention taken along line A-A of FIG. 3. The cable 109 that connects the probe 203 to a spectrometer display (not shown) can be seen along with an opening in the rear of the shielded housing 101 to accommodate the exit path of the cable 109. FIG. 6 is a top plan view of the collimator-probe of the present invention. The cable 109 can be seen protruding from the shielded housing 101. The opening in the rear of the shielded housing 101 is such that a tight fit between the shielded housing 101 and the cable 109 are provided. Turning to FIGS. 7-11, a phantom setup 700 can be seen that creates a calibration standard through the use of a spectrometer that can be used in determining the radiological composition of the corrosion layers within a pipe. FIG. 7 is a perspective view of the phantom setup 700 of the present invention. The collimator-probe 100, as previously described herein, can be seen. A vessel 703 such as a nuclear medicine phantom, is seen mounted to a base 709. The base 709 includes walls or edges to contain a spill should it occur. The base 709 may be made from a plastic such as polypropylene, acetyl, polycarbonate, or a metal such as stainless steel or the like. The vessel 703 may be made from a plastic such as polycarbonate or the like. A first fill/vent plug 705 and a second fill/vent plug 707 are fit to the vessel 703 in a manner that provides a leak free seal. Threaded fittings with a gasket, friction fittings with a gasket, or the like may be used. The vessel 703 may, in one embodiment, be rectangular, and may, by example, be 26 inches×16 inches×0.5 inches internal volume. The vessel 703 is configured in the vertical position, and may contain a radioactive water mix, such as, for example, 600 cubic centimeters of liquid including 2 cubic centimeters of Co-60 (containing 65.5 uCi), and 2 cubic centimeters of Cs-137 (containing 72.7 uCi) with the balance being, for example, water. The vessel 703 may be, in one embodiment, 1 centimeter thick with 600 square centimeters of exposure surface area. Placed between the collimator-probe 100 and the filled vessel 703 is a series of plates 711 and also insulation 701. The series of plates 711 comprise steel plates of a given thickness, for example, 0.25 inches. The series of plates 711 may comprise, for example, 12 total plates, each of 0.25 inches thickness, for a total starting thickness of 3 inches. The insulation 701 represents a typical thickness of nuclear insulation. A first gusset 713 and a second gusset 801 (see FIG. 8) may be employed to secure the vessel 703 in a proper upright position, as depicted in FIG. 7. With the phantom setup described, readings may be taken at incremental plate thicknesses by removing or adding plates for each reading. In addition, readings with and without the nuclear insulation 701 are taken. FIG. 8 is a top plan view of the phantom setup of the present invention depicting the vessel 703 containing the activity source and the collimator-probe taking readings through the plates 711 and insulation 701. FIG. 9 is a rear plan view of the phantom setup of the present invention that shows the orientation of the vessel 703 in relation to the collimator-probe 100, plates 711 and insulation 701. FIG. 10 is a cross sectional view of the phantom setup of the present invention taken along line B-B of FIG. 9. In cross section, the reactor water test standard 1001 can be seen. A reactor water test standard 1001 may include, for example, 600 cubic centimeters of water, 2 cubic centimeters of Co-60 (containing 65.5 uCi), and 2 cubic centimeters of Cs-137 (containing 72.7 uCi). FIGS. 11A-11N depict the phantom setup in use with sequential removal or addition of plates and insulation. In FIG. 11A, all plates and the insulation are in place. FIG. 11B depicts one plate removed, FIG. 11C depicts two plates removed, FIG. 11D depicts three plates removed, and so on. FIG. 11L thus depicts one plate remaining, and FIG. 11M depicts no plates remaining, only insulation. Lastly, FIG. 11N depicts no plates or insulation between the collimator-probe and the vessel. For each step portrayed in FIGS. 11A-11N, a radioisotopic activity reading is taken and recorded. A plot of log(10) of activity vs. steel thickness in 0.25 inch increments (or the appropriate units) is then prepared. The plot can then be used in removing “the confounder” when taking field measurements of radiological sedimentation in pipes. Now when field measurements of radioisotopic activity are taken to determine the radiological sedimentation present within a pipe, the plot of log(10) of activity vs. steel thickness can be used to remove the unknown variables and obtain true and accurate readings. FIGS. 12-15 depict such field measurements. FIG. 12 is a perspective view of a typical field setup 1200 of the present invention showing the collimator-probe attached to an insulated pipe. The collimator-probe 100 is held up to the insulation 1201 of a pipe 1203. The corrosion layer 1205 and associated activity from the corrosion layer is an unknown, and is measured through a known pipe thickness and pipe insulation thickness. Field readings are taken and adjusted by using the plot of log(10) of activity vs. steel thickness in the previously described, phantom calibration measurements. FIG. 13 depicts a plan view of as typical field setup of the present invention showing the collimator-probe attached to an insulated pipe. FIG. 14 depicts an end view of a typical field setup of the present invention showing the corrosion layer within an insulated pipe. FIG. 15 depicts a cross sectional view of the insulated pipe taken along line C-C of FIG. 13. FIG. 16 is a flowchart of a method of establishing a baseline using the phantom setup. In step 1601, the phantom is established. This involves preparing the phantom setup 700 as previously described herein. Once the phantom is established and ready for measurements, the plate thickness (t) is determined in step 1603 by adding the total number of plates in the setup, for example, eleven ¼ inch plates, for a total thickness of 2.75 inches. The plates may be, for example, steel plates. In step 1605, insulation is established. A layer of nuclear insulation of a known thickness and material is added. In step 1607, n readings are taken. For example three readings, one of Cs-134, one of Cs-137 and one of Co-60. In step 1609, one plate is removed, n readings are again taken, the plate thickness is decreased in step 1609 to a thickness of t−x/k where x is a counter that is incremented by one in step 1615 and k is the inverse of the plate thickness per plate. For example, with ¼ inch plates k is equal to 4. After each decrement in step 1615, it readings are taken in step 1611, and step 1613 determines if the final plate has been removed by determining if the overall thickness, for example, 2.75 inches, equals the current value of x (for example, 11) divided by k (for example 4). If the answer is no, the plates will continue to be decremented and n readings taken until such time as t=x/k. In step 1617, a numerical graph is produced, in step 1619 the graph is extrapolated to zero, and in step 1621 as baseline data set is created to be used to remove the confounder in subsequent field measurements, as previously described herein. The graph is typically plotted using a semi-logarithmic scale, and is a straight line. The slope of the resulting line becomes a calibration factor which, based on the radioisotopes used, reflects the conditions within an enclosed system. FIG. 17 is a flowchart of a method of determining the radiological composition of a corrosion layer within a pipe. Once the phantom setup has produced a baseline data set or sets, field measurements may be taken to accurately determine the radiological composition of a corrosion layer within a pipe. In step 1701, the thickness of the pipe is input. In step 1703, n reading's are taken that are dependent on the source materials of interest. Once the readings are taken in step 1703, in step 1705 the readings are compared to the baseline data set from the phantom measurements described previously. This comparison removes the pipe, insulation, and other confounding attenuation factors from the measurements, providing sediment layer values in step 1707. Optionally, in step 1709, the detriment of the corrosion layer is determined, and in optional step 1711 the sources of the detriment are determined. In addition, in step 1713 optionally corrective actions are suggested to reduce corrosion and its impact. It should be noted that the steps performed herein may be manually performed, or they may be embodied in a computer program on a computer or on any device having, a processor including meters, probes, gauges, or other such instrumentation. Having described an exemplary system and method for determining the radiological composition of material layers within a conduit, one can envision various embodiments thereof. These embodiments are to be considered within the spirit and broad scope of the present invention. For example, FIGS. 18-29 depict an alternate embodiment of the collimator-probe and provide examples of accessories that can be employed to facilitate convenience of use and the like. The shielded housing in this example is split in two halves that mate together and are held by fixturing such as clamps, straps, screws, bolts, or the like. It is important to note that the mating surfaces of each half should preferably have relief, angles, or other geometric changes to ensure proper shielding. FIG. 18 depicts a perspective view of an alternate embodiment of the collimator-probe of the present invention with accessories. The shielded housing depicted is generally cylindrical, and may in some embodiments have a flattened bottom portion to facilitate placement of the collimator-probe on a flat work surface or floor. An example of suitable dimensions for a generally cylindrical shielded housing is a cylinder that is approximately 8 centimeters tall with a diameter of 6 centimeters. The wall thickness of this exemplary cylinder is approximately 1.4 centimeters. The shielded housing is made from a high density material such as lead, tungsten, depleted uranium, or the like to provide proper shielding. The shielded housing is also covered with a material such as copper to allow for rapid decontamination. Such a covering is made by electroplating, forming of a suitable foil around the shielded housing, painting, or the like. Both the inside and the outside of the shielded housing are covered with such a material. The shielded housing may be cast, molded, machined, or otherwise formed into a generally hollow structure such as a cylinder that is capable of containing a probe, such as the probe 2201 depicted in FIG. 22. In addition, a soft material such as a plastic sponge material may line the inside of the shielded housing in order to secure the probe 2201 (see FIG. 22) and keep it centered within the shielded housing. In the case of this alternate embodiment, the shielded housing is made in two parts, a first half 1801 and a second half 1803, as depicted in FIGS. 18-29. To facilitate not only proper alignment of the two halves, but also proper shielding, each half has a feature such as a mating surface that may include protrusions, channels, slots, wedges, threads, tabs, pins, posts, sockets, and the like. In the example depicted, the first half of the shielded housing 1801 has a first channel 1823 and a second channel 1825 that each lie along a peripheral wall of the first half 1801 where each channel is generally parallel to the cylindrical axis that is formed with the joining of the first half and the second half to create a cylinder. The channels may take various geometries. In the example depicted, the channels are triangular, but may, in some embodiments, be square, rectangular, round, elliptical, octagonal, hexagonal, or the like. On the second half of the shielded housing 1803, a first protrusion 1819 and a second protrusion 1821 can be seen. Each of these protrusions mates with the related channel on the first half of the shielded housing 1801, and similar to the related channels, each protrusion lies along a peripheral wall of the second half 1803 where each protrusion is generally parallel to the cylindrical axis that is formed with the joining of the first half and the second half to create a cylinder. The protrusions may take various geometries. In the example depicted, the protrusions are triangular, but may, in some embodiments, be square, rectangular, round, elliptical, octagonal, hexagonal, or the like. The two halves of the shielded housing retain a probe (depicted as 2201 in FIG. 22). The two halves are joined together such that the probe and related cable 1809 are properly placed and secured in the respective cavity of each half. The cable 1809 exits the joined together shielded housing through a channel in each half with a radius of curvature of each channel sufficient to prevent kinking or other maladies of the cable and probe assembly. The cable 1809 connects the probe to instrumentation 1817 such as a spectrometer. In FIG. 18, a carry strap 1815 can be seen with integral joining straps that traverse the perimeter of the shielded housing to retain the two halves together. These straps may be the only means of retaining the two halves, or alternatively or in combination, clamps, screws, bolts, rivets, or other such hardware may be employed. The straps may be made from as nylon, polypropylene, leather, or the like. It can be seen in FIG. 18 that the exemplary cylindrical shielded housing has a flattened bottom portion to allow placement on a flat surface without rolling. In addition, in some embodiments of the present invention, tripod fixturing such as a threaded insert may be added to allow use of the collimator-probe with a tripod 1813 or other such support structure. Once a probe is installed in the shielded housing and the two halves are placed together and retained, one can see an opening 1811 in the resulting shielded housing. The opening 1811 may be of various geometries, but is depicted as a round opening in this example. This opening provides for detection capabilities for the probe contained within the shielded housing. To prevent low energy lateral photons from hitting the face of the probe, a grid 1807 is placed and secured within the opening 1811. The grid 1807 is made from a high density material such as lead, tungsten or depleted uranium and prevents low energy lateral photons from hitting the face of the probe, which would result in incorrect readings. An example of a suitable grid is a three by three matrix of lead plates where each plate is 1/16 inch thick and 1 centimeter deep. The lead plates are aligned to create a grid that comprises a plurality of openings. The grid 1807 may also be east, machined, or otherwise fabricated such that a plurality of openings are created. The openings may be rectangular, square, circular, or the like. A spacer 1805 and the grid 1807 are retained in the opening 1811 by use of glue, adhesives, solder, retainer rings, clips, or the like. FIG. 19 depicts a perspective view of the alternate embodiment of the collimator-probe of FIG. 18. The mating halves can be clearly seen in the assembled and operational position. The probe is contained within the shielded enclosure formed from the two halves. The mating protrusion and channel arrangement can be seen along with a flattened portion of the cylinder to prevent rolling or movement of the unit when placed on a surface, of which some embodiments of the present invention may employ. FIG. 20 is an opposite side perspective view of the alternate embodiment of the collimator-probe of FIG. 18 showing similar attributes to the side depicted in FIG. 19. To clearly show the protrusion and channel arrangement of the first half of the shielded housing 1801 and the second half of the shielded housing 1803, FIG. 21 portrays a front plan view of the collimator-probe of FIG. 18. The grid 1807 and opening 1811 can also be clearly seen, the grid 1807 depicted herein by example and not limitation comprising a plurality of circular holes. In some embodiments of the present invention, the grid 1807 may comprise holes, openings or apertures that are square, rectangular, oval, hexagonal, octagonal, or the like. The spacer 1805 may be made from various materials, geometric shapes, or may, in some embodiments of the present invention, be omitted entirely. Further, in some embodiments of the present invention the grid 1807 may be integral with the shielded housing or a portion or a half thereof. FIG. 22 is a cross-sectional view of the collimator-probe taken along line D-D of FIG. 21 where the inner structure of the shielded housing can be seen. In some embodiments of the present invention, the inner structure depicted in FIG. 22 is common to both the first half of the shielded housing 1801 and the second half of the shielded housing 1803. The structure depicted in FIG. 22 may be formed or made by casting, machining, cutting, grinding, heat forming, laser cutting or etching, chemical processes such as etching, and the like. The probe 2201 can be seen occupying a cavity that is similar in shape to that of the probe 2201. For clarity, the internal structure of the probe 2201 is not depicted. An air gap 2203 can be seen between the face of the probe and the grid 1807. The air gap 2203 may also, in some embodiments of the present invention, be occupied by a material such as a foam, a plastic, various spacers, or the like to provide, for example, structural definition to the air gap 2203. Further, in some embodiments of the present invention, the thickness of the air gap 2203 is zero or thereabouts, essentially meaning that there is no air gap 2203, or one that is minimal. A probe retainer 2205 may also be employed in some embodiments of the present invention to provide for adequate cushioning, conformal fit and retention of the probe 2201. The probe retainer 2205 is made from a soft material such as a low density polyethylene foam or the like. A low density material provides a low attenuation coefficient and is thus desirable to avoid erroneous readings. In some embodiments of the present invention, the probe retainer 2205 is secured only by friction, without the use of glue. Within the probe retainer 2205 is the probe 2201. A suitable probe is a cadmium Zinc Telluride (CZT) probe such as those made by Canberra of Meriden, Conn., USA. The CZT probes made by Canberra may also be used with their Inspector 1000 display. Various size probes are available based on the energy range of interest A 500 mm3 probe adequately monitors a maximum dose rate of 200 mrem/hr. A 60 mm3 probe has an upper range of 1,000 mrem/hr. The probe 2201 is positioned such that its sensing surface is facing outward through the opening 1811. While a probe retainer 2205 may not be necessary in all situations and embodiments of the present invention, it may in some cases be useful and beneficial. A cadmium layer 2207 can also be seen which is in turn covered by a copper layer 2211 or a layer of tin and copper to allow for rapid decontamination. Such a layer is made by electroplating, forming of a suitable foil around the shielded housing, painting, or the like. The shielded housing itself is made from a shielding material 2209 such as lead, tungsten, depleted uranium or the like. FIG. 23 is an exploded view of the collimator-probe of FIG. 18 where each of the piece pans previously described can be seen in further detail. Shown is one example of the cable recess 2301 taking a curvature that travels from the recess that contains the probe itself toward the peripheral edge of the second half of the shielded housing 1803 but not entering the protrusion 1821, or in the case of the first half of the shielded housing 1801, not entering the channel 1825. Also seen in FIG. 23 is a cable termination recess 2303 as well as a probe recess 2305. These recesses are formed by casting, molding, machining, etching, or the like. The geometries of these recesses are dictated by the shape of the probe and related cable and fixturing to be contained by the shielded housing. FIG. 24 is as perspective view of a first half of the shielded housing of the collimator-probe of FIG. 18 showing some of the details previously described herein. FIG. 25 is a front plan view of the first half of the shielded housing of the collimator-probe of FIG. 18 and FIG. 26 is an inside plan view of the first half of the shielded housing of the collimator-probe of FIG. 18. FIG. 27 is a perspective view of a second half of the shielded housing 1803 of the collimator-probe of FIG. 18 also showing some of the details previously described herein. Features in this second half of the shielded housing 1803 such as the cable recess 2701, cable termination recess 2703 and probe recess 2705 being the second half of those features in the first half of the shielded housing 1801 such as the cable recess 2301, cable termination recess 2303 and probe recess 2305 that are described by way of FIG. 23. FIG. 28 is a front plan view of the second half of the shielded housing of the collimator-probe of FIG. 18 and FIG. 29 is an inside plan view of the second half of the shielded housing of the collimator-probe of FIG. 18. While the systems and methods disclosed herein are described as being applied to nuclear power plant pipes, they are equally applicable to other conduits and vessels, as well as uses such as medical applications to determine, for example, vessel thickness, occlusion, scarring, or the like in humans and animals. It is, therefore, apparent that there has been provided, in accordance with the various objects of the present invention, a System and Method For Determining The Radiological Composition of Material Layers Within a Conduit. While the various objects of this invention have been described in conjunction with preferred embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of this specification, claims and drawings appended herein. |
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abstract | Zirconium-based metal alloy compositions comprise zirconium, a first additive in which the permeability of hydrogen decreases with increasing temperatures at least over a temperature range extending from 350° C. to 750° C., and a second additive having a solubility in zirconium over the temperature range extending from 350° C. to 750° C. At least one of a solubility of the first additive in the second additive over the temperature range extending from 350° C. to 750° C. and a solubility of the second additive in the first additive over the temperature range extending from 350° C. to 750° C. is higher than the solubility of the second additive in zirconium over the temperature range extending from 350° C. to 750° C. Nuclear fuel rods include a cladding material comprising such metal alloy compositions, and nuclear reactors include such fuel rods. Methods are used to fabricate such zirconium-based metal alloy compositions. |
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description | This application claims benefit of U.S. Provisional Application No. 60/496,886, entitled “Sputtered Contamination Shielding for an Ion Source” and filed Aug. 20, 2003, incorporated herein by reference for all that it discloses and teaches. The invention relates generally to ion sources, and more particularly to shielding for an ion source. Generally, an ion source is a device that ionizes gas molecules and focuses, accelerates, and emits the ionized gas molecules and/or atoms in a beam for a variety of technical and industrial applications. For example, ion sources may be used as thrusters on space craft. Ion sources are also used in semiconductor material and device processing, optical filter processing, and metrology, among other applications. Common uses of ion sources include without limitation cleaning, assisting deposition (by chemically or physically activating), polishing, etching and/or depositing of thin-film coatings. Typically, a substrate is passed through an ion beam (e.g., an etching beam) for such processing. An anode layer source (ALS) typically refers to a Hall-current type ion source having a grounded cathode and a DC-biased anode. The working gas is fed into an ionization region in the vicinity of the anode and the cathode, where the combination of electric and magnetic fields in this region ionizes the molecules of the working gas and accelerates each ion away from the ionization region toward a target. The ionization region generally forms a closed-loop (e.g., a race track shape) in the face of the ion source. The shape of this closed-loop “race track” may be round, oval, linear with rounded ends, or many other closed shapes. One benefit to an ALS is that an ALS does not require a hot cathode electron source (e.g., filament cathode, hollow cathode, or RF neutralizer) with a separate power supply to sustain the plasma. ALS cathodes are passive, cold cathodes, typically made of steel. The cathodes also function as pole pieces for the ALS magnetic circuit. The cold cathodes do not actively emit electrons, but ions bombarding the cathodes release secondary electrons that help to sustain the discharge. One problem with an ALS, however, is that the ions striking the cathodes can also sputter material from the cathodes. The sputtered cathode material may enter the process as a contaminant. Such cathodes are typically steel or magnetic stainless steel, so the primary contaminant is iron, although other contaminants may also exist. The sputtered material tends to emit across a wide range of angles. As a result, the sputtered material tends to impinge the substrate surface outside the envelope of the etching beam as well as inside the envelope of the etching beam. Depending on the type of ion source, the operating regime, and the application, there may be other ion source electrodes or adjacent components that also sputter in a similar matter and contribute to substrate contamination. Most contaminants impinging the substrate surface prior to and during the passing of the substrate through the etching beam are etched away by the beam. However, the contaminants that impinge the surface of the substrate after the substrate has passed through the etching beam remain as contaminants. In other words, a substrate tends to acquire a new layer of contaminants after exiting the envelope of the ion beam. Therefore, for example, etching a substrate using an ALS may yield an etched substrate having an unacceptable concentration of iron contaminants sputtered from the ALS itself. Implementations described and claimed herein solve the discussed problems by providing shielding associated with an ion source, such as an ALS. The shield configuration allows the etching ions to pass to the substrate and effectively blocks sputtered contaminants from impinging the target substrate outside the envelope of the etching beam. Such shielding associated with an ion source reduces the number of sputtered contaminants impinging and remaining on the surface of a target substrate. While passing the ion beam through to the target substrate, shielding can reduce the total number of sputtered contaminants impinging the substrate before, during, and/or after passage of the substrate through the envelope of the etching beam. Particularly, a shield configuration that blocks the contaminants from impinging the substrate after the substrate passes through the etching beam (i.e., outside of the envelope of the etching beam) yields a higher quality substrate (i.e., with lower contamination levels). In one implementation, an ion source system for processing a substrate along a substrate location path is provided. An ion source generates an ion beam. A shield is positioned between the ion source and the substrate location to pass the ion beam to the substrate while blocking sputtered contaminants from impinging the substrate. In another implementation, a shielding system positionable between an ion source and a substrate location is provided. The shielding system passes an ion beam from an ion source to impinge a substrate on the substrate location while blocking sputtered contaminants from impinging the substrate. In yet another implementation, a method of processing a substrate is provided. An ion beam is generated and sputters ions from an ion source having a cathode, the ion beam defining an envelope. The substrate passes through the envelope. Sputtered contaminants are sputtered from the cathode by the sputtering ions. The sputtered contaminants are blocked from impinging the substrate outside of the envelope of the ion beam. In yet another embodiment, an ion source system includes an ion source; and means for passing an ion beam from the ion source to impinge a substrate while blocking sputtered contaminants from impinging the substrate. Using shielding in association with an ion source can reduce the total number of sputtered contaminants striking and remaining on the surface of a target substrate. A shield configuration can block the sputtered contaminants from impinging the substrate outside the envelope of the ion beam. Many, but not all, contaminants that impinge the substrate during (and prior to) the passage of the substrate through the envelope of the etching beam are etched away from the substrate by the beam. In one implementation, blocking such contaminants from impinging the substrate surface after the substrate passes through the etching beam (i.e., outside of the envelope of the etching beam) significantly reduced contamination of the substrate surface, although generally reducing the number of sputtered contaminants reaching the surface of the substrate improves substrate quality as well (e.g., resulting in about a 50% reduction in substrate contamination). FIG. 1 illustrates a cross-sectional schematic view of an ion source with exemplary emitter shields, which are adjacent to the ion source. An ion source processing system 100 includes an ion source 102, and emitter shields 104, 106, and 108. The target of the processing is a substrate 110, which is positioned or passed at some distance from the emission face 101 of the ion source 102. The ion source 102 produces an ion beam on an ion beam axis 114, where an ion beam envelope is defined by arrows 112 and the ion beam axis 114 is substantially perpendicular to the emission face 101. The substrate 110 is passed through the ion beam envelope 112, substantially perpendicular to the ion beam axis 114, although geometries with non-perpendicular ion beam emission and/or impingement are also contemplated. In addition, ion beam emission intensity and direction may be different for different portions or sides of the ionization region. In a typical configuration, multiple substrates are passed sequentially through the ion beam for processing along this perpendicular path, although other configurations may involve one or more stationary substrates. In one exemplary type of ALS, called a linear ALS, the ion beam is linear (e.g., long and narrow) as defined by a closed oval ionization region or channel with long, straight sides (see, for example, FIGS. 5 and 6). Typical applications of linear ALS systems include processing large flat substrates with substrate motion generally perpendicular to the longitudinal axis of the beam (i.e., perpendicular to the straight section of the ionization channel). Linear ALS systems, other types of ALS systems, and other types of ion beam sources may benefit from the described technology. Some generated ions (i.e., sputtering ions) impinge the cathodes 116 and 117, causing cathode material to sputter (shown by arrows 118) from the cathodes 116 and 117. The sputtered material can enter the process as a contaminant on the surface of the substrate 110. For example, absent the shields 104, 106, and 108, when the substrate 110 is in positions 122 and 124, sputtered material from the cathodes 116 and 117 may impinge the substrate 110, thereby contaminating the surface of the substrate 110. In addition, regardless of the presence of the shields 104, 106, and 108, sputtered material from the cathodes 116 and 117 may impinge the substrate 110 while passing through the width 120 of the ion beam on the substrate path. The ion beam width is dependent upon the envelope defined by edges of the ion beam and the distance between the ionization region of the ion source and the substrate path. A substantial amount of the sputtered contaminants impinging the surface of the substrate 110 before (e.g., at position 122) and during passage of the substrate 110 through the ion beam is etched away by the beam. Some such contaminants remain. Therefore, reducing the total amount of contaminants impinging the surface of the substrate can improve the quality of the substrate. Furthermore, any contaminants impinging the surface of the substrate 110 after passage through the far edge of the ion beam envelope 112 (e.g., see general location referenced by arrow 113) remain on the surface because none are etched away. Therefore, reducing the amount of contaminants impinging the surface of the substrate after passage through the ion beam can reduce substrate contamination. By positioning shields 104, 106, and 108 to block sputtered contaminants that are directed outside of the envelope of the ion beam, the sputtered contaminant count is dramatically reduced on the surface of the substrate 110. The outside shield 104 extends upright (i.e., at a greater than 0° angle to a 90° angle) from the face of the ion source 102 and is positioned outside and along one of the long channels of the ionization region of the ion source. The outside shield 104 blocks sputtered contaminants emitted to the left in FIG. 1 from the cathodes 116 of the ion source 102. The end point 126 of the outside shield 104 is positioned to pass a substantial amount of the ion beam while blocking sputtered contaminants emitted outside the ion beam envelope. The inside shield 106 blocks sputtered contaminants emitted to the right in FIG. 1 from the cathodes 116 of the ion source 102 and to the left in FIG. 1 from the cathodes 117 of the ion source 102. The inside shield 106 extends upright (e.g., at a greater than 0° angle to a 90° angle) from the emission face 101 of the ion source 102 and is positioned between the long channels of the ionization region of the ion source. The end point 128 of the inside shield 106 is positioned to pass a substantial amount of the ion beam while blocking sputtered contaminants emitted outside the inside edge portions of the envelope of the ion beam emitted from cathodes 116 and 117. The outside shield 108 blocks sputtered contaminants emitted to the right in FIG. 1 from the cathodes 117 of the ion source 102. The outside shield 108 extends upright (e.g., at a greater than 0° angle to a 90° angle) from the emission face 101 of the ion source 102 and is positioned outside and along the other long channel of the ionization region of the ion source. The end point 130 of the outside shield 108 is positioned to pass a substantial amount of the ion beam while blocking sputtered contaminants emitted outside the ion beam envelope. In addition, end shields (not shown in FIG. 1, but examples may be seen in FIGS. 5-8) may also be employed to block sputtered material emitted from the ends of an ALS (e.g., the curved end portions of the ionization channels 502 and 702 of ion sources 500 and 700, respectively, in FIGS. 5-8). It should be understood that the inside shields, the outside shields, and the end shields may or may not be physically attached to the ion source itself. In some operating conditions, the shields may be sputtered the by ion beam (e.g., depending upon the height, shape, location, and composition of the shields and the shape and intensity of the ion beam). As such, shields may be fabricated out of materials that are not process contaminants, such as titanium in a titanium-oxide deposition process, and/or that have a very low sputter yield (collectively “process-compatible” materials). In addition to shield materials being sputtered into the process, some of the cathode or anode materials may be initially sputtered from the ion source to impinge the shield and then be “re-sputtered” from the shield into the process. As such, shields may be positioned with an inward tilt, provided with a louvered design, or manufactured with a honeycomb or similar structured material to trap sputtered contaminants to reduce forward sputtering of contaminant material. FIG. 2 illustrates a more detailed cross-sectional schematic view of an ion source with exemplary emitter shields. The system 200 includes a closed-field ion source 202 and emitter shields 204, 206, and 208, which extend outward from the face of the ion source 202. (An open-field anode layer ion source may be employed in an alternative implementation. Also, implementations may be applied to end-Hall ion sources and various other ion sources. Moreover, ion sources where the edges of the contaminant distribution zone (e.g., 118 in FIG. 1) is broader than the edges of the ion beam (e.g., beam 112 in FIG. 1) may gain particular benefit from such described shielding. In addition, such ion source beam shapes may vary and may include circular shapes, annular shapes, etc.) A working gas is emitted behind the anode 210 through inlet 211, flows around the anode 210, and is ionized at an ionization region 212 through interaction of an electric field generated by the power source 214 and a magnetic field generated by permanent magnets 215. The anode 210 is made of a non-magnetic material, such as 300 series stainless steel. A cathode 216 is made of magnetic material, such as carbon steel or 400 series stainless steel. The combination of the electric field and the magnetic field creates the ions and accelerates them away from the ionization region 212, as represented by dashed beam lines 218, toward a target (e.g., a substrate). However, some ions created at the ionization region 212 bombard the surface of the cathode 216 near the ionization region 212 and, therefore, sputter cathode material away from the ionization region 212, as represented by the exemplary directional arrows 220 and 222. The sputtered material can enter the ion beam process as a contaminant, such as by impinging the surface of the substrate. In some ion source applications, gases that can form some negative ions as well as the usual positive ions, such as oxygen, may be used. These negative ions can sputter the anode and result in sputtered anode material entering the process as a contaminant in a manner similar to that described herein for cathode sputtering. As such, the shielding described herein may be used to block anode sputtered contaminants and other contaminants as well. As can be seen in FIG. 2, the sputtered material corresponding to arrows 220 strikes the surfaces of the shields 204, 206, and 208, and is effectively blocked from impinging the target. In contrast, the sputtered material corresponding to the arrows 222 bypasses the shields 204, 206, and 208 and may impinge the target. However, the sputtered material corresponding to the arrows 222 remains within the envelope of the ion beam 218 and is therefore substantially etched away from the substrate by the ion beam during processing. Accordingly, the heights of the shields 204, 206, and 208 (relative to the ionization region 212) are set to substantially block sputtered material that is emitted outside the ion beam envelope 218, while substantially allowing the ion beam (and sputtered material emitted within the ion beam envelope) to pass to the target. Likewise, the widths of the shields 204, 206, and 208 (or the distances of the shields 204, 206, and 208 from adjacent ionization regions) are set with at least the same constraints. FIG. 3 illustrates a cross-sectional schematic view of an ion source with exemplary substrate shields, which are adjacent to the substrate path. An ion source processing system 300 includes an ion source 302 and substrate shields 304 and 306. The target of the processing is a substrate 308, which is located or passed at some distance from the emission face 301. The substrate 308 is passed through an ion beam (defined by dashed arrows 310). In a typical configuration, multiple substrates are passed sequentially through the ion beam for processing along this path parallel to the emission face 301, although non-parallel paths may also be employed. Some generated ions (i.e., sputtering ions) bombard the cathodes 312 and 314, causing cathode material to sputter (shown by solid arrows 316 and 318) from the cathodes 312 and 314. As mentioned earlier, cathode sputtered contaminants are just one type of contaminant material that may enter the process. Other contaminant materials may also be sputtered off of other surfaces of the ion source or enter the process through other means. The sputtered material can enter the process as a contaminant on the surface of the substrate 308. For example, absent the shields 304 and 306, when the substrate is outside the ion beam envelope, sputtered material from the cathodes 312 and 314 may impinge the substrate 308, thereby contaminating the surface of the substrate 308. In addition, regardless of the presence of the shields 304 and 306, sputtered material from the cathodes 312 and 314 may impinge the substrate 308 while passing through the ion beam envelope. However, a substantial amount of the sputtered contaminant impinging the surface of the substrate 308 before and during passage of the substrate 308 through the ion beam is etched away by the ion beam. However, any contaminant impinging the surface of the substrate 308 after passage through the ion beam remains on the surface. By positioning shields 304 and 306 to block sputtered contaminants that are directed outside of the ion beam envelope, the sputtered contaminant count reaching the substrate is dramatically reduced on the surface of the substrate 308. It should be understood, however, that such shields may be positioned along an ion beam axis near to the substrate location, near to the emission face 301, or at some distance in between the substrate location and the emission face 301. FIG. 4 illustrates a more detailed cross-sectional schematic view of an ion source with exemplary substrate shields. The system 400 includes an open-field ion source 402, although a closed-field ion source may be employed in an alternative implementation. The system 400 also includes substrate shields 404 and 406, which are positioned substantially parallel to the face of the ion source 402 (although non-parallel configurations are also contemplated). A working gas is emitted from the anode 408 and ionized at the ionization region 410 through the interaction of an electric field generated by the power source 412 and a magnetic field generated by permanent magnets 424. The anode 408 is made of a non-magnetic material, such as 300 series stainless steel. A cathode 414 is made of magnetic material, such as carbon steel or 400 series steel. The combination of the electric field and the magnetic field creates the ions and accelerates them away from the ionization region 410, as represented by dashed beam lines 416, toward a target (e.g., a substrate). For open-field sources, additional magnets and pole pieces may be used to provide an extended acceleration zone to enhance low energy operation and stability. Sputtering of these extended components can also be a source of contamination. However, some ions created at the ionization region 410 bombard the surface of the cathode 414 near the ionization region 410 (as well as other surfaces) and, therefore, sputter cathode material away from the ionization region 410, as represented by the exemplary directional arrows 418 and 420. The sputtered material enters the ion beam process as a contaminant, such as by reaching the surface of a substrate 422. As can be seen in FIG. 4, the sputtered material corresponding to arrows 418 strikes the surfaces of the shields 404 and 406, and is effectively blocked from reaching the target substrate 422. In contrast, the sputtered material corresponding to the arrows 420 bypasses the shields 404 and 406 and may impinge the target substrate 422. However, the sputtered material corresponding to the arrows 420 remains within the envelope of the ion beam 416 and is therefore substantially etched away from the target substrate by the ion beam during processing. Accordingly, the separation between the shields (404 and 406) and the substrate path and the separation between and relative alignment between the shields (404 and 406) and the ionization regions 410 are set to block sputtered material that is emitted outside the ion beam envelope, while allowing the ion beam (and sputtered material emitted within the ion beam envelope) to pass to the target. FIG. 5 illustrates a face of an ion source 500 with exemplary emitter shields. FIG. 6 illustrates a perspective view of the ion source 500 of FIG. 5 with exemplary emitter shields. An ion source 500 includes an oval ionization region 502 in which a working gas is ionized and from which ions are emitted. In operation, the ion source 500 emits ions from the ionization region 502 in the form of an ion beam. A substrate (not shown) is passed through the ion beam for processing (e.g., at some distance from the face of the ion source). In an exemplary embodiment, a substrate is transported along a path perpendicular to (or some other angle relative to) the long axis of the ion source 500, which emits an ion beam from the ionization region 502 toward the surface of the substrate as it passes. It should be understood that some benefits may result for a non-perpendicular substrate path, including increasing power density, reducing overspray on a source longer than the width of the substrate, and smoothing out small longitudinal beam non-uniformities. There may also be benefits for a non-perpendicular angle of emission from the ion source and/or a non-perpendicular angle of ion impingement on the substrate. It should also be noted that the angle of the beam may be modified dynamically during the emission. Benefits may also be achieved from operating with the shields at some other electrical potential relative to the ion source housing (e.g., electrical isolation/floating and/or active biasing at a positive potential). Emitter shields 504, 506, and 508 are positioned between the ion source 500 and the path of the substrate along the long channel portions of the ionization region 502. In various embodiments, one or two of the shields 504, 506, and 508 may be omitted. However, to best block sputtered contaminants from impinging the substrate surface after the substrate has passed through the ion beam, one of the shields is maintained on the far edge of the ion source (i.e., farthest in the direction of substrate motion). Nevertheless, each shield, singly or in combination with other shields, may decrease the total amount of sputtered contaminants reaching or remaining on the surface of the substrate, thereby improving substrate quality. In the illustrated implementation, and in addition to emitter shields 504, 506, and 508, end shields 510 and 512 may be employed to block sputtered contaminants from the rounded ends of the ion source 500. Each end shield 510 and 512 may be configured (e.g. shaped, placed and sized) to block all emitted ions and sputtered contaminants emanating from the rounded ionization region 502 region in the ends of the ion source 500. For example, the end shields 510 and 512 may be much taller than the emitter shields 504, 506, and 508, which are sized to substantially pass the ion beam and substantially block the sputtered contaminants. Alternatively, the end shields 510 and 512 may be positioned, sized, and shaped to pass a portion of the ion beam and to substantially block the sputtered contaminants. FIG. 7 illustrates a face of another ion source 700 with exemplary emitter shields. FIG. 8 illustrates a perspective view of the ion source 700 of FIG. 7 with exemplary emitter shields. An ion source 700 includes an oval ionization region 702 in which a working gas is ionized. In operation, the ion source 700 emits ions from the ionization region 702 in the form of an ion beam. A substrate (not shown) is transported through the ion beam for processing (e.g., at some distance from the face of the ion source). In an exemplary embodiment, a substrate is transported along a path perpendicular to the long axis of the ion source 700, which emits an ion beam from the ionization region 702 toward the surface of the substrate as it passes. Emitter shields 704, 706, and 708 are positioned between the ion source 700 and the path of the substrate along the long channel portions of the ionization region 702, as discussed with regard to FIGS. 5 and 6. Likewise, in various embodiments, one or two of the shields 504, 506, and 508 may be omitted. In addition to emitter shields 704, 706, and 708, end shields 710 and 712 may be employed to block sputtered contaminants from the rounded ends of the ion source 700. The end shields 710 and 712 are shaped to improve the amount of the ion beam that is passed while substantially blocking the sputtered contaminants. The rounded shape substantially matches the rounded shape of the ionization region 702 at the ends of the ion source 700. In this configuration, the size and positioning of the end shields 710 and 712 are set to substantially pass the ion beam and to substantially block the sputtered contaminants from reaching the substrate. The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments of the invention. However, other implementations are also contemplated within the scope of the present invention, including without limitation shields having different shapes, sizes, and locations than those shown, as well as systems having one or more shields and systems with or without one or more end shields. In addition, while the description has described exemplary ion sources as ALSs, other ion sources may be employed within the scope of the invention. Since many implementations can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended. |
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description | This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/317,257, filed Sep. 4, 2001, the disclosure of which is incorporated herein by reference. In one aspect, this invention relates to measuring elements present in coal, ores, and other substances using energy dispersive X-ray fluorescence (XRF) spectroscopy. In another aspect, the invention relates to different apparatuses and methods for use in conjunction with elemental analyzers. Techniques for analyzing or measuring the elemental composition of a substance, such as coal, using X-ray fluorescence (XRF), are well-known in the art. An example of one technique is disclosed in U.S. Pat. No. 6,130,931, the disclosure of which is incorporated herein by reference. While these XRF techniques work extraordinary well for measuring certain elements, such as sulfur, the ability to measure “trace elements” (e.g., vanadium, chromium, manganese, cobalt, nickel, copper, zinc, arsenic, selenium, and molybdenum) has previously been limited to laboratory techniques involving extensive preparation using pulverized samples. For instance, ASTM Standard Test Method D4606 for the determination of arsenic and selenium in coal by the Hydride Generation/Atomic Absorption Method analyzes a 1.0 gram sample of coal pulverized to pass a 250 mm standard sieve. ASTM Standard Test Method D6357 for the Determination of Trace Elements in Coal, Coke, and Combustion Residues from Coal Utilizations Processes by Inductively Coupled Plasma Mass Spectrometry and Graphite Furnace Atomic Absorption Spectrometry analyzes a 0.5 gram sample of coal ash ground to pass 150 μm. The wet chemistry methods dictated by standard laboratory methods are time consuming and can only produce a single analysis in a matter of hours. Turn around time in commercial laboratories is often days or weeks and the analysis is very expensive. U.S. Pat. No. 5,020,084 to Robertson, which is also incorporated herein by reference, proposes the use of X-ray energy at a level of 100–130 kilo-electron-volts (KeV) to measure a finely divided heavy metal (gold) dispersed in a non-metallic matrix using K emission bands. However, this patent does not mention the use of low energy XRF to measure trace elements, including gold. Moreover, it dismisses L emission XRF techniques as inaccurate. Furthermore, high energy XRF cannot be used to detect the K emission bands of the lighter trace elements with atomic numbers less than or equal to 48 (Cadmium). Thus, the approach taught in the Robertson patent is not a solution to the problems identified in the foregoing paragraph. In one aspect, the present invention is an on-line sensor or sensing device for measuring (monitoring, detecting, sensing, etc.) one or more elements in a material, including the presence of trace elements down to levels of less than 1 part per million (ppm) or μg/g with relatively short analysis times (possibly as short as 2–6 minutes). This is accomplished using low energy (less than 80 KeV and, more preferably, less than 65 KeV) X-rays to bombard the stream of with X-rays in a bandwidth designed to optimally excite the characteristic K or L emission bands of the element(s) of interest. Using this system, it is possible to detect fluoresced emissions with energies as low as 1.0 KeV. Consequently, trace elements present in coal (defined by ASTM as those elements whose individual concentrations are generally less than 0.01%) such as vanadium, chromium, manganese, cobalt, nickel, copper, zinc, arsenic, selenium, and molybdenum each have Kα or Kβ emission bands that can be readily measured by this XRF technique. Mercury and lead Lα emission bands can also be measured using this technique. Other metals dispersed in mineral ores in small or trace quantities, such as platinum and gold, can also be measured with low energy XRF, again using the Lα emission bands. In one embodiment, an adjustable voltage X-ray tube is used as the source. This allows for the incident X-ray energies to be adjusted, preferably to within a range of 1.5–3.0 times the energy of the characteristic emission bands from the elements of interest to maximize the efficiency of emission. It is also possible to use filters to narrow the band of incident X-rays, which further reduces the amount of interference, as well as a slotted collimator for collimating the X-ray energy emitted from the source. Providing an optimal X-ray source:detector (sensor) geometry and positioning the sensor as close as possible to the surface of the material also enhances the results. In accordance with another aspect of the invention, a sled for supporting a sensor, such as an XRF sensor, adjacent to a moving stream of material is disclosed. The sled is mounted so as to be capable of swinging to and fro in response to changes in the profile of the material. It may also be designed to aid in further compacting the material to help ensure that an accurate reading is taken by the sensor. Other manners of mounting a sensor and, in particular, and XRF sensor are also disclosed, including: (1) mounting the sensor in a probe for positioning in a borehole; and (2) mounting two sensors inline along a moving stream of material, with one sensing trace elements only and the other sensing the “lighter” elements. Reference is now made to FIGS. 1a and 1b, which show one embodiment of an XRF trace element sensor 10 mounted adjacent to an endless transfer conveyor belt 12 carrying a substance or material, such as coal C. The belt 12 and sensor 10 in combination may form part of a mechanical sampling system 14 for measuring the elemental composition of a sample of material, such as ore or coal C delivered from a chute H or the like. The sample may be supplied from a main conveyor line (not shown), and is preferably crushed or pulverized to have a particle size of approximately less than or equal to 10 millimeters (⅜ths of an inch) prior to being delivered to the sampling system 14. In this system 14, a leveling structure and skirting (not shown) along the sides of the belt 10 together help to assure that a constant or substantially constant geometry of coal C or other substance is presented to the sensor 10 forming part of the system 14. In FIG. 1a, the leveling structure is shown as a rotatable drum 16 capable of being moved toward and away from the surface of the belt 12 (note action arrow A), depending on the profile of the material being conveyed. However, the leveling structure of FIG. 1a could also be considered a stationary cylinder that is also movable toward and away from the belt 12. Instead of a rotatable drum or stationary cylinder, a leveling plow 18 could also be used to compact the material, as shown in FIG. 1b. Any combination of these structures could also be used, as could structures not disclosed herein, as long as the function of assuring a level, constant or substantially constant profile is achieved. A material sensor 20 may also be provided upstream of the elemental sensor 10 for indicating the presence of material on the belt 12. Opposed microwave moisture sensors 22a, 22b may also be positioned adjacent to the belt 12 for providing moisture readings, if desired. As discussed in detail further below, outputs from each of the sensors, as well as from the system 10, may be fed to a remote computer or controller through suitable transmission lines (see FIG. 2) for further use, display, or processing, as necessary or desired to measuring the elemental composition or another characteristic of the material sample. FIG. 2 provides a generally schematic view of the overall arrangement of the sensors 10, 20, 22a, and 22b, with portions of the coal C and the belt 12 cut away for clarity. The elemental sensor 10 includes an X-ray source 24 (typically an X-ray tube) and an X-ray detector 26 (typically an Si-PIN diode) positioned in a backscattering configuration adjacent to the surface of the coal C. The source and detector 24, 26 may be positioned in an instrument enclosure or box 28 having an opening covered by a window (not shown) through which the X-ray energy passes (not shown). The window may be thin (such as 0.9 mil polypropylene) to seal the enclosure 28 from fugitive dust. Since the window will absorb a fraction of the low energy X-rays, the opening may be left open to maximize the transmission of X-rays to the detector 26. When no window is employed, a positive gas pressure (air or other gas, such as helium) may be applied to the instrument enclosure, sufficient to prevent dust from entering. In a most preferred embodiment, an adjustable voltage X-ray tube is used as the source 24. This allows for the incident X-ray energies to be adjusted, preferably to within the range of 1.5–3.0 times the energy of the characteristic emission bands from the elements of interest to maximize the efficiency of emission. The X-ray source 24 is connected to a high voltage power supply 30, which may be included as part of a remote “power box” 32 also including power supply 34. As is known in the art, an interlock 36 including a warning light X and a switch may also be associated with the high voltage power supply 30 for safety and security reasons. The power box 32 may also enclose or include the device for receiving an output signal from the X-ray detector 26, such as a multi-channel analyzer (MCA) 38. A pre-amplifier and power source, identified collectively by reference numeral 37 may also be connected to the MCA 38, preferably in the instrument enclosure 28. The MCA 38 may also be coupled to and receive a signal from the material sensor 20. The outputs from the moisture sensors 22a, 22b may be connected to a separate moisture processor 40 capable of receiving and processing the analog signals. Both the MCA 38 and the moisture processor 40 may be coupled to a remote computer 42 for providing an indication of the measurements taken by the sensors (e.g., elemental composition, moisture content, etc.), such as using a monitor or display. FIG. 3a shows a preferred geometry of the X-ray source 24 and detector 26 of the present invention (which are shown in the reversed positions, as compared to FIG. 2). The source 24 is mounted adjacent to the detector 26 such that both are generally directed toward the material for which the analysis is desired, preferably about two inches from the surface thereof (and in some cases, such as when sodium is being measured, less than 0.5 inches). Preferably, the angle between a transmission axis T of the source 24 and a detection axis D of the sensor or detector 26 is an acute angle, preferably between about 65° and 90°, and, most preferably about 78°, while the angle between the transmission axis T and a plane parallel to the sample surface is also an acute angle, most preferably about 57°. To facilitate changing the position (height, spacing, or angle) of either the source 24 and the detector 26, both are independently mounted in an adjustable fashion on stable mounting structures, such as using slotted brackets 44 and corresponding fasteners 46 (e.g., nut and bolt combinations). The particular adjustable mounting used is not considered critical to the invention, as long as the desired geometry is achieved. When conveying bulk materials, such as coal, the particles shift laterally across the conveyor 12. Thus, the shape of the interrogation (measuring) zone is more distorted. To reduce the effects of varying profile in the material conveyed past the sensor 10, a collimator 48 may optionally be positioned adjacent to the source 24. Specifically, the collimator 48 is used to collimate the X-rays emitted from the source 24. Preferably, as shown in FIG. 3b, the collimator 48 includes an elongated slot 50 having a major dimension M oriented in the same direction as the material is being conveyed (that is, parallel to the direction in which the material is traveling). The collimator 48 may include openings 51 for facilitating mounting to the X-ray source 24. To further narrow the bandwidth of incident X-rays in order to excite a particular element(s) with a high degree of efficiency, a filter 52 may also be employed between the X-ray source and the material to be measured. Filter 52 may be comprised of metal and may have a thickness of 10 μm to 4 mm, depending on the energy and intensity of the incident X-rays. As perhaps best shown in FIG. 3c, the filter 52 is preferably interposed between the window 24a on the X-ray source 24 (which is normally made of beryllium) and the collimator 48, if present. Common filter materials are copper, zinc, nickel, zirconium, niobium, molybdenum or any other materials that can eliminate or reduce the X-rays in a particular energy range emanating from an X-ray source. Alloys such as brass can also prove to be effective filters as well. Preferably, the collimator 48 is fabricated of aluminum or the same material as the filter 52. Direct measurement of the K and L emission bands from a number of trace elements is possible with the sensor 10 described above. As an example, FIG. 4a shows a broad spectrum generated with the present invention using an X-ray tube as the source 24 with a molybdenum filament, a copper filter 52 mounted next to the tube window 24a, as shown in FIG. 3. The trace element of interest in this case is arsenic (As). FIG. 4b is an enlargement of the same spectrum showing the resolution of the Kα and Kβ emission bands for arsenic. In this sample, the concentration of arsenic was 23 ppm. Using this sensor 10 with different X-ray energies at less than 80 KeV, preferably less than 65 KeV, still more preferably between 20–65 KeV, and most preferably around 40–45 KeV, it is possible to measure trace elements including vanadium, chromium, manganese, cobalt, nickel, copper, zinc, and molybdenum using the Kα and Kβ emission bands. Mercury and lead Lα emission bands can also be measured using this technique (which could be of great benefit when measuring trace quantities of these metals in water). Other metals, such as platinum and gold dispersed in mineral ores in small or trace quantities can also be measured with low energy (less than 80 KeV) XRF, again using the Lα emission bands. Instead of the arrangements shown in FIGS. 1a and 1b, the XRF trace element sensor 10 described above can be mounted directly adjacent to a moving stream of material on a conveyor (not shown) using a sled 56, as depicted in FIG. 5a. The sled 56 includes a base 58 for assisting in leveling and compacting the material passing underneath the sensor 10 so the profile is substantially constant. The base 58 is sized for supporting the sensor 10 (source/detector) adjacent to an opening 58a (see FIG. 5c), as well as the instrument enclosure 28. The base 58 may also include an opening 58b that may be associated with a sensor 20 for detecting the presence of material adjacent to the sled 56. The sled 56 further includes a pair of elongated runners 60, 62. Each runner 60, 62 may be attached directly to one side of the base 58 (FIG. 5b). As perhaps best shown in FIG. 5c, the runners 60, 62 are preferably converging or narrowing relative to one another along the direction in which the material is traveling (note direction of material travel G in FIG. 5a). As should be appreciated, this further helps to compact the material as it moves towards the sensor 10 positioned downstream from the leading edge of the sled 56. Consequently, the sled 56 is particularly useful with moving streams of material that have a particle size of up to about 50 millimeters, or 2 inches, in size. The sled 56 is preferably supported by a stable support structure 64 and mounted such that it is capable of moving in response to changes in the geometry or profile of the material being conveyed. In one embodiment, as shown in FIG. 5a, the sled 56 is mounted so as to be capable of swinging to an fro along a generally arcuate path. Specifically, at least two swing arms, and preferably two pairs of swing arms 66 support the sled 56 from the stable support structure 64. The swing arms 66 are mounted to pivot structures 70 at each end such that the sled 56 is capable of swinging to and fro along a generally arcuate path. The mounting is preferably of a type that prevents the ends of the swing arms 66 adjacent to the support structure from moving in the vertical direction (as opposed to the smooth arcuate movement allowed by the pivoting of swing arms 66), which keeps vibrations to a minimum. A shock absorber or damper, such as a spring 72 (represented schematically in FIG. 5a), may also be associated with the sled 56 to resist the swinging movement. For example, the spring 72 may extend between one or both pairs of swing arms 66 on each side of the sled 56, as shown in FIG. 5a. Alternatively, it could be provided between individual swing arms and a stable structure, between the base and a stable structure, or between one or more of the swing arms and the base. The sled 56 may also include a leveling and smoothing structure 74. Preferably, this structure 74 is mounted along the leading edge of the base 58 and is designed to help compact and smooth the upper surface of the material as it is presented to the onboard sensor 10. It is shown as having a generally arcuate cross-section when viewed from the side, but may have any shape that accomplishes the desired function. A separate smoothing or leveling structure, such as a drum, roller, bar, or the like (not shown) may also be provided upstream of the leading edge of the base 56 of the sled 58. This structure maybe the only leveling structure, or it may be used in combination with structure 74. As shown in FIG. 5b, the sled 56 may hang freely above the conveyor or other structure along which the material is traveling. Preferably, the sled 56 is positioned such that, in a nominal or free hanging position, it is about 6 inches above the conveyor where the normal bed depth is 8–10 inches. Thus, when the material is on the conveyor at the normal depth, the engagement with the leveling structure 74 causes the sled 56 to move or pivot along an arcuate path, generally in the direction of travel, as shown in FIG. 5a. In this position, it should be appreciated that the weight of the sled 56 still helps to compact the material as it moves toward the sensor 10. This is true even if the spring 72 and counterweight 78 are present. To facilitate adjusting the position of the sled 56 toward or away from the conveyor, adjustable length arms 66 may be provided. Alternatively, the position of the support structure may be made adjustable, such as by using an adjustable height support frame. In addition, one or both of the leading pair of swing arms 66 may be extended beyond the pivot structure 70 on the distal end (identified with reference numeral 66′) and carry or support an adjustable counterweight 78. Consequently, the position of the counterweight 78 along the arm(s) 66′ may be adjusted to help counterbalance the weight of the sled 56 (which may be around 200 pounds) to help keep it in intimate contact with the upper surface of the moving stream of material without severely disrupting the flow. This helps to ensure that a more accurate reading is achieved by the sensor 10. The sensor 10 used with the sled 56 need not be for measuring trace elements, but instead could be used for measuring lighter elements, as described in U.S. Pat. No. 6,130,931. The sensor 10 may also be used in other possible arrangements, including configurations where the material is stationary. For example, as shown in FIG. 6, the sensor 10 may be in the form of a probe 80 adapted for being positioned or inserted in a borehole E for measuring the elemental composition of the adjacent wall W. Specifically, the X-ray source 24 and X-ray detector 26 are shown as being positioned in a backscatter configuration adjacent to a window 82 formed in the sidewall of the probe 80. The detector 26 may be coupled to an onboard MCA and amplifier 86, while the source 24 is coupled to an onboard power supply 88. The MCA/amplifier 86 and power supply 88 may in turn be coupled to data and power lines L, respectively, emanating from a remote location outside to borehole E. In the case where the borehole E is oriented vertically, a support line, such as a steel rope R, cable, or the like may also be secured to the probe 80 to assist in raising and lowering it. A sensor 10 similar to that shown in FIGS. 1a and 1b could also be mounted on the underside of a chute (not shown) carrying the material past the sensor in a fixed geometry, or it could be mounted to a flow cell to measure concentrations of trace elements in liquids or slurries. The sensor 10 could also be mounted on or adjacent to the cutter head or shearer on a mining machine, such as a highwall miner (not shown) to take measurements from the cutting face. In all cases, the sensor 10 need not be used for measuring trace elements, but instead could be used for measuring lighter elements, as described in U.S. Pat. No. 6,130,931. Correlation of the element of interest with other elements in the material to correct for matrix effects may be done using a multiple linear regression calibration relationship of the form:E=K0+K1C1+K2C2+K3C1C2+K4C12+K5C5+ . . . +KxCx+KyCy . . .Where, E=Element of interest K=Constant C=Count rate under a region of interest (peak).Therefore, combining multiple X-ray sources wherein one is at a first level (e.g., <15 KeV) to cause efficient Kα emission of the “lighter” elements (atomic numbers <30) and a second X-ray source is at a second, higher level (e.g., >15 KeV) to cause efficient Kα emission of the “heavier” elements (atomic numbers >30) provides a system by which matrix effects can be corrected and relationships developed between various elements occurring in a mineral matrix together. This can dramatically improve the accuracy of the measurement. A similar improvement may be gained by using an adjustable voltage X-ray tube, as described above, controlled by a computer or a programmable logic controller (PLC). It is also possible to measure each element in a range of elements, including trace elements, from sodium (atomic number 11) through krypton (atomic number 36) using a properly configured single source. An example of a sampling system 90 including two X-ray sources and detectors for measuring both lighter and heavier elements in the material is shown in FIG. 7 in use adjacent to a moving belt 12. Specifically, the system 90 includes a leveling device, such as drum 16, a first sensor 10 constructed substantially as described in FIG. 1, and moisture sensors 22a, 22b connected to a processor 40. The sensor 10 includes an X-ray source 24 for projecting X-ray energy greater than from about 15 KeV and up to about 65 KeV. Emissions detected by the corresponding detector are processed and sent to a computer 42 to measure the trace elements in the passing stream of material. A substantially identical sensor 100 is positioned in the same or an adjacent instrument enclosure 128, and includes an X-ray source 124 for directing X-ray energy in the range of 3–15 KeV towards the material. The source 124 may be coupled to a high voltage power supply 130 including an interlock 136, and a power supply 134 may also be provided. A second detector 126 detects the fluorescence and sends a second output signal, preferably through a pre-amplifier 137 to an analyzer, such as MCA 138 (which may be powered by a power supply associated with the pre-amplifier). The computer 42 then displays the measured elements corresponding to the range of energies emitted by the second source 124. The second sensor 100 may be substantially identical to the one shown in U.S. Pat. No. 6,130,931. The foregoing description of several embodiments of the invention have been presented for purposes of illustration and description. The description is not intended to be exhaustive or to limit the invention to the precise form disclosed. The embodiments were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled. |
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abstract | The invention relates to an after loader apparatus for treatment of tumours in an animal body comprising a housing with at least one exchangeable radiation source connected to a first end of a transport wire, which wire is connected with its other end to transport means for advancing said transport wire and said radiation source through a guide tube to and from a tumour in said body, where at least the radiation source and the transport wire are mounted in an exchangeable radiation shielded after loader cartridge, which cartridge can be placed in a suitable receptable opening present in said housing. |
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description | The subject matter described herein generally relates medical imaging, and in particular to a system and method to guide movement of an instrument or tool through an imaged subject. Fluoroscopic imaging generally includes acquiring low-dose radiological images of anatomical structures such as the arteries enhanced by injecting a radio-opaque contrast agent into the imaged subject. The acquired fluoroscopic images allow acquisition and illustration of real-time movement of high-contrast materials (e.g., tools, bones, etc.) located in the region of interest of the imaged subject. However, the anatomical structure of the vascular system of the imaged subject is generally not clearly illustrated except for that portion with the injected contrast medium flowing through. There is a need for an imaging system with enhanced visibility of the object (e.g., surgical tools, catheters, etc.) travelling through the imaged subject relative to surrounding superimposed imaging anatomical structures. There is also a need for a system and method of imaging with enhanced captured image details of objects travelling through the imaged subject, so as allow reduction of a volume of contrast medium injected into the imaged subject. The above-mentioned need is addressed by the embodiments described herein in the following description. According to one embodiment, a system to track movement of an object travelling through an imaged subject is provided. The system includes a fluoroscopic imaging system operable to acquire a fluoroscopic image of the object within a region of interest of the imaged subject, an imaging system operable to create a three-dimensional model of the region of interest of the imaged subject, and a controller comprising a memory operable to store a plurality of computer-readable program instructions for execution by a processor. The plurality of program instructions are representative of the steps of a) calculating a probability that an acquired image data is of the object, the calculating step performed per pixel in the fluoroscopic image; b) calculating a value of a blending coefficient per pixel of the fluoroscopic image dependent on the probability calculated in step (a); c) creating an output image comprising the fluoroscopic image and the three-dimensional model, the step of creating including blending the fluoroscopic image and the three-dimensional model according to the blending coefficient of step (b). According to another embodiment, a method to track movement of an object travelling through an imaged subject is provided. The method includes the steps of a) calculating a probability that an acquired image data is of the object, the calculating step performed per pixel in a fluoroscopic image of the imaged subject; b) calculating a value of a blending coefficient per pixel of the fluoroscopic image dependent on the probability calculated in step (a); c) creating an output image comprising the fluoroscopic image and the three-dimensional model, the step of creating including blending the fluoroscopic image and the three-dimensional model according to the blending coefficient of step (b). An embodiment of a system to track movement of an object through an imaged subject is also provided. The system includes a fluoroscopic imaging system operable to acquire a fluoroscopic image of the object within a region of interest of the imaged subject; an imaging system operable to create a three-dimensional model of the region of interest of the imaged subject; and a controller comprising a memory operable to store a plurality of computer-readable program instructions for execution by a processor. The plurality of program instructions are representative of the steps of a) calculating a probability that an acquired image data is of the object, the calculating step performed per pixel in the fluoroscopic image, b) registering the fluoroscopic image and the three-dimensional of the region of the interest in spatial relation to a common coordinate system, c) calculating a value of a transparency per pixel of the three-dimensional model dependent on the probability per respective pixel of the fluoroscopic image as calculated in step (a), d) adjusting the three-dimensional according to the value of transparency per pixel of step (c), and d) combining the fluoroscopic image with the three-dimensional model adjusted according to step (c) to create an output image illustrative of the object in spatial relation to the three-dimensional model. In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments, which may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments, and it is to be understood that other embodiments may be utilized and that logical, mechanical, electrical and other changes may be made without departing from the scope of the embodiments. The following detailed description is, therefore, not to be taken in a limiting sense. FIG. 1 illustrates an embodiment of a system 100 to track movement or navigation of an image-guided object or tool 105 through an imaged subject 110. The system 100 comprises an imaging system 115 operable to acquire an image or a sequence of images or image frames 120 (e.g., x-ray image, fluoroscopic image, magnetic resonance image, real-time endoscopic image, etc. or combination thereof) illustrative of the location of the object 105 in the imaged subject 110. Thus, it should be understood that reference to the image 120 can include one or a sequence of images or image frames. One embodiment of the image-guided object or structure 105 includes a catheter or guidewire configured to deploy a stent at a desired position in a vascular vessel structure of the imaged subject 110. The imaging system 115 is generally operable to generate a two-dimensional, three-dimensional, or four-dimensional image data corresponding to an area of interest of the imaged subject 110. The type of imaging system 115 can include, but is not limited to, computed tomography (CT), magnetic resonance imaging (MRI), x-ray, positron emission tomography (PET), ultrasound, angiographic, fluoroscopic, and the like or combination thereof. The imaging system 115 can be of the type operable to generate static images acquired by static imaging detectors (e.g., CT systems, MRI systems, etc.) prior to a medical procedure, or of the type operable to acquire real-time images with real-time imaging detectors (e.g., angioplastic systems, laparoscopic systems, endoscopic systems, etc.) during the medical procedure. Thus, the types of images can be diagnostic or interventional. One embodiment of the imaging system 115 includes a static image acquiring system in combination with a real-time image acquiring system. Another embodiment of the imaging system 115 is configured to generate a fusion of an image acquired by a CT imaging system with an image acquired by an MR imaging system. This embodiment can be employed in the surgical removal of tumors. One example of the imaging system 115 generally includes a fluoroscopic imaging system having an energy source projecting energy (e.g., x-rays) 122 through the imaged subject 110 to be received at a detector in a conventional manner. The energy is attenuated as it passes through imaged subject 110, until impinging upon the detector, generating the image or image frames 120 illustrative of a region of interest 125 of the imaged subject 110. This example of the imaging system 115 also includes a software product or package operable to combine a series of acquired images (e.g., CT type images) to generate a three-dimensional, reconstructed image or model 170 representative of the internal structure or organs of interest. An embodiment of the software product operable to create the reconstructed three-dimensional image is INNOVA® 3D as manufactured by GENERAL ELECTRIC®. The software product is also operable to measure a volume, a diameter, and a general morphology of a vessel (e.g., vein, artery, etc.) or other anatomical structures. The image or sequence of acquired image frames 120 is digitized and communicated to a controller 130 for recording and storage in a memory 135. The controller 130 further includes a processor 140 operable to execute the programmable instructions stored in the memory 135 of the system 100. The programmable instructions are generally configured to instruct the processor 140 to perform image processing on the sequence of acquired images or image frames 120 for illustration on a display. One embodiment of the memory 135 includes a hard-drive of a computer integrated with the system 100. The memory 135 can also include a computer readable storage medium such as a floppy disk, CD, DVD, etc. or combination thereof known in the art. Having generally provided the above-description of the construction of the system 100, the following is a discussion of a method 200 of operating the system 100 to navigate or track movement of the object 105 through the imaged subject 110. It should be understood that the following discussion may discuss acts or steps not required to operate the system 100, and also that operation can include additional steps not described herein. An embodiment of the acts or steps can be in the form of a series of computer-readable program instructions stored in the memory 135 for execution by the processor 140 of the controller 130. A technical effect of the system 100 and method 200 is to enhance visualization of the object 105 relative to other illustrated features of the superimposed, three-dimensional model of the region of interest of the imaged subject 110. More specifically, a technical effect of the system 100 and method 200 is to enhance illustration of the object 105 without sacrificing contrast in illustration of the three-dimensional reconstructed image or model 170 of anatomical structure in the region of interest 125 of the imaged subject 110. Referring now to FIG. 2, step 202 is the start. Step 205 includes generating or creating the three-dimensional reconstructed model 170 of the region of interest 125 from the series of acquired images 120. An example of the three-dimensional model is a dual-energy x-ray absorptiotiometry (DXA) model generated by a LUNAR IDXA™ as manufactured by GENERAL ELECTRIC® Healthcare in the diagnosis of monitoring of bone density disease. Step 210 includes acquiring a two-dimensional, low-radiation dose, fluoroscopic image 215 with the imaging system 115 in a conventional manner of the imaged subject 110. An injected contrast agent can be used to enhance the image 215, but is not necessary with the system 100 and method 200 disclosed herein. Step 220 includes registering the fluoroscopic image 215 for later combination, fusion, or placement in superimposition with the three-dimensional model 170 according to a common reference or coordinate system 222. It should be understood that the source (CT imaging system, fluoroscopic imaging system, picture archival system (PACs), MRI, PET, ultrasound, etc.) of the three-dimensional model 170 and/or fluoroscopic image 215 can vary. Step 225 includes identifying or detecting the pixels in the fluoroscopic image 215 having increased likelihood or probability of corresponding or correlating to including image data of the object 105. An embodiment of step 225 includes calculating a probability that an acquired image data is of the object 105 on a per pixel basis for at least a portion or all of the fluoroscopic image 215. An embodiment of calculating the probability can include applying a dilation technique to the fluoroscopic image 215 so as to increase a dimension or size of the imaged object 105 illustrated therein. For example, the object 105 can include a very thin wire that is difficult or too small to identify following superimposition of the fluoroscopic image with the three-dimensional model. To increase the contrast of the object 105, candidate pixels suspected to include image data of the object 105 can be dilated using known techniques of mathematical morphology so as to increase a size of the illustration of the imaged object 105 as captured in the fluoroscopic image 215. Another embodiment of the step 225 of calculating the probability per pixel includes comparing image data per pixel to predetermined or stored or calibrated image data correlated to the object 105. Another embodiment of step 225 can include calculating the probability on a per pixel basis dependent on or correlated to tracking data of the object 105 as acquired by a navigation system in a known manner. Another embodiment of step 225 includes identifying a target region 230 having a series of pixels calculated within a predetermined range of probability of including image data of the object 105. Step 225 can also include applying a steerable filter or oriented filters in a known manner to reduce noise in the target region 230 of the fluoroscopic image 215. Calculation of the probability per pixel can be updated periodically or continuously with periodic or continuous updates of the fluoroscopic image 215 in real-time with movement of the object 105 through the imaged subject 110. Step 240 includes calculating image adjustment parameters as a function of measured values of the pixelated data (e.g., greyscale value) detected in target region of the fluoroscopic image 215. Examples of image adjustment parameters include rendering, projection, or blending parameters associated with superimposition, combining, or fusion of the three-dimensional reconstructed image or model 170 with the fluoroscopic image 215 of the object 105 so as to enhance illustration of the target region 230 of the fluoroscopic image 215 without reducing detailed illustration of the anatomical structures in the three-dimensional model 170. There are several projection parameters that may be identified or altered so as to adjust fusion, superimposition, or combination of fluoroscopic image 215 and the three-dimensional model 170. The projection parameters can depend on the desired information to be highlighted according to image analysis or input from the user. An example of a projection parameter is a level of transparency of the pixels comprising the fluoroscopic image 215 and the three-dimensional model 170 relative to the other in their superposition or fusion with one another to create an output image 275. An embodiment of step 240 includes calculating a level or degree of transparency of the three-dimensional model 170 relative to the fluoroscopic image 215 on a per pixel basis dependent on the calculated probabilities. An embodiment of calculating the degree of transparency generally includes calculating a proportion of a value of light transmission relative to or dependent upon a calculated probability of the associated pixel including image data of the object as calculated in step 225. The degree of transparency of each pixel is calculated dependent upon the probability of including image data of the object 105 so as to cause illustration of the surrounding anatomical structures in the three-dimensional model 170 to be more transparent in the combined output image 275. According to an embodiment of calculating the transparency of a pixel by pixel basis includes increasing a value of opacity or contrast or light intensity of each pixel in proportion with an increased probability of including captured image data of the walls of the anatomical structures surrounding the object 105 relative to pixels with image data of either side of the anatomical structural walls (e.g., internalized structures). FIGS. 3 and 4 illustrate embodiments of an influence of adjusting the transparency parameter for a three-dimensional model 300 and 305, respectively, similar to the three-dimensional model 170 described above. FIG. 3 illustrates an embodiment of the three-dimensional reconstructed image or model 300 with the rendering parameter selected or set to about zero percent transparency, referred to as a surface rendering, so that a surface of the anatomical structure 310 is displayed rather than then internalized structures located therein. In contrast, FIG. 4 illustrates the three-dimensional reconstructed model 305 with the rendering parameter selected or set to an increased transparency, relative to model 300 of FIG. 3, such that the illustration of a surface of the anatomical structure 325 is more transparent (e.g., seventy percent transparency) so as to illustrate detailed imaged data of the internalized structure located therein or lack thereof. In the illustrated example, the value of transparency of the pixels that illustrate image data of the walls 330 and 335 of the structure 325 is lower relative to value of transparency of the pixels that illustrate image data on either side of the walls 330 and 335. An embodiment of calculating or adjusting a blending parameter according to step 240 includes calculating a value of a blending parameter on a per pixel basis to one or both the fluoroscopic image 215 and the three-dimensional reconstructed model 170. The blending parameter or factor generally specifies what proportion of each component (e.g., the fluoroscopic image 215 and the three-dimensional reconstructed model 170) to be superimposed or fused relative to the other in creating the output image 275. An embodiment of a blending technique in applying the blending factor to the superposition or fusion of the fluoroscopic image 215 with the three-dimensional reconstructed image or model 170 includes identifying or selecting a blending factor or coefficient that proportions (e.g., linearly, exponentially, etc.) the superposition or fusion of the fluoroscopic image 215 with the three-dimensional reconstructed image or model 170. An embodiment of a linear blending technique is according to the following mathematical representation or formula:Fused_image=(alpha factor)*(target region of the fluoro_image)+(1−alpha factor)*(three-dimensional reconstructed image or model),where the alpha factor is a first blending coefficient to be multiplied with the measured greyscale, contrast or intensity value for each pixel in the target region 230 of the fluoroscopic image 215, and the (1−alpha factor) is a second blending coefficient to be multiplied with the measured greyscale, contrast, or intensity value for each pixel of the three-dimensional reconstructed model 170 outside the superimposed, fused, or combined target region 230 of the fluoroscopic image 215. According to another embodiment of the alpha technique, the above mathematical representation or formula can further include another blending coefficient (i.e., gamma) equal to about zero that is multiplied with a greyscale, contrast, or intensity value for every pixel in the three-dimensional model 170 that is not associated with an anatomical structure or otherwise an anatomical structure of interest. Another example of the blending technique can include more blending factors or coefficients, as shown in the following mathematical representation:Fused_image=(alpha factor)*(pixel value of fluoro_image)+(beta factor)*(pixel value of anatomical 3D_image)+(gamma factor)*(pixel value of non-anatomical 3D image),where the alpha factor, beta factor, and gamma factor are individually identified and selected as predetermined stored values in the memory 135 or received via the input 145. According to one embodiment of step 240, each of the blending factors (e.g., alpha factor, beta factor, gamma factor, 1−alpha factor) described above is calculated per pixel having a particular x, y coordinate dependent on or in proportion to the calculated probability of the respective pixel including image data of the object 105 as described in step 225. One or more of the above-described blending factors is applied on a per pixel basis to adjust the target region image 230 of the image 215 or the model 170 as function according to a two- or three-dimensional coordinate system 222 identified in common reference to the three-dimensional reconstructed model 170 and/or in reference to the fluoroscopic image 215. This embodiment of step 240 can be represented by the following mathematical representation:alpha factor=f(x,y),where the alpha factor is a blending factor associated each pixel and dependent on or proportional to the calculated probability of the respective pixel including image data of the object 105 as described in step 225, and where (x) and (y) represent coordinates in the coordinate system 222 defining a common reference of a spatial relation of each pixel of the fluoroscopic image 215 and the three-dimensional reconstructed model 170 fused, superimposed, or combined to create the output image 275. According to an example of this embodiment, step 240 includes identifying and applying a first blending factor alpha to calculate the greyscale, contrast, or intensity values of the pixels of the three-dimensional model 170 projecting in combination, fusion or superposition within the limits of the target region 230 of the fluoroscopic image 215 to create the output image 275. Step 240 further includes identifying and applying or multiplying a second blending factor (the second blending factor lower relative to the first blending factor) to calculate the greyscale, contrast, or intensity values per pixel of remaining pixels of the three-dimensional model 170 projecting outside the limits of the target region 230 and to the remainder of the fluoroscopic image 215. Different blending factors can applied to calculate the greyscale, contrast, or intensity values per pixel of the fluoroscopic image 215 relative to the remainder of the fluoroscopic image 215 in a similar manner. The step 240 can be performed periodically or continuously in real-time as the target region 230 of the fluoroscopic image 215 moves with the object 105 through the imaged subject 110. Referring now to FIG. 5, an embodiment of step 240 can further include identifying a model transition portion 340 (illustrated by cross-hatching) of a three-dimensional model 350, similar to the model 170 described above, extending between the pixels of the model 350 (e.g., within a target region 355 similar to the target region 230 described above) and the pixels of the model 350 at a spaced distance 360 outward from the target region 355. Another embodiment of the step 240 can include identifying a model transition portion 340 including a series of pixels located between a first pixel of a first location with coordinate x1, y1, and a second pixel of a second location with coordinate x2, y2. Step 240 can further include identifying and multiplying a first transitional blending algorithm to calculate the greyscale, contrast, or intensity values per pixel within the model transition portion 340. In a similar manner and as illustrated in FIG. 6, step 240 can also include identifying a fluoroscopic transition portion 380 (illustrated by cross-hatching) of a fluoroscopic image 385 (similar to the fluoroscopic image 215 described above) extending between pixels of a first and second coordinate, or alternatively the pixels within an analogous target region 390 and the remainder of pixels of the fluoroscopic image 385 at a spaced distance 395 outside the target region 390. The fluoroscopic transition portion 380 is generally similar in shape and size to the model transition portion 340 in FIG. 5. Step 240 can further include multiplying a transitional blending algorithm to calculate the greyscale, contrast, or intensity values per pixel in the fluoroscopic transition portion 380. Examples of the transitional blending algorithm can be a continuous linear change or transition, a stepped linear transition, or a continuous exponential change or transition in value between the first and second blending factors described above. It should be understood that the target regions 230, 355 and 395 described above can vary in shape (e.g., window, polygram, envelope spaced at a constant distance from an outer surface of the object 105) in conformance with the shape of the object 105. Also, it should be understood that other known image processing techniques to vary projection of the fluoroscopic image 215 in superposition with the three-dimensional reconstructed model 170 can be used in combination with the system 100 and method 200 described above. Accordingly, the step 240 can include identifying and applying a combination of the above-described techniques in varying or adjusting values of projection parameters (e.g., transparency, intensity, opacity, blending) on a pixel by pixel basis or a coordinate basis (e.g., x-y coordinate system, polar coordinate system, etc.) in superimposing, fusing, or combining the fluoroscopic image 215 with the three-dimensional reconstructed model 170 of the surrounding anatomical structure. Referring back to FIG. 2, step 400 includes combining, superimposing, or fusing the image data of at least a portion of the three-dimensional model 170 adjusted as described above in step 230 with the image data of at least a portion of the two-dimensional fluoroscopic image 215 adjusted as described in step 230 so to create the output image 275 illustrative of the object 105 in spatial relation to the reconstructed anatomical structures of the model 170. An embodiment of step 400 includes combining, fusing or superimposing the fluoroscopic image 215 with a two-dimensional, volume rendering illustration of the model 170. Step 405 includes re-adjusting the value of the image adjustment parameters (e.g., projection, rendering, etc.) as described above in step 240 until a desired detailed illustration of the object 105 and the surrounding anatomical structure of the model 170 is achieved. Step 405 can include adjusting values of the transparency or blending coefficients on a per pixel basis according to instructions received via the input 145. Step 410 is the end. A technical effect of the above-described method 200 and system 100 is to enhance illustration or increase contrast of both the object 105 as captured in the target region 230 of the fluoroscopic image 215 as well as illustration of the surrounding anatomical structure as generated in three-dimensional reconstructed image or model 170 in the process of fusing, superimposing, or combining the image 215 and model 170 together to create the output image 275. Another technical effect of the above-described method 200 and system 100 is to reduce or avoid the necessity of injecting a contrast agent into the imaged subject 110 to acquire visual image data of movement of the object 105 therethrough. This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The scope of the subject matter described herein is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. |
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claims | 1. A method of extracting a lamella from a substrate comprising;placing the substrate with the lamella to be extracted on a moveable stage, the lamella being physically attached to the substrate;moving a microprobe into contact with the lamella, the microprobe comprising a hollow tube connected to a vacuum source and open at the microprobe tip;applying a vacuum through the microprobe tip so that the vacuum holds the sample against the microprobe tip;lifting the microprobe with attached sample away from the substrate, severing the attachment of the lamella to the substrate;moving the microprobe so that the sample is in contact with a desired position on a sample holder;moving the microprobe away from the released sample. 2. The method of claim 1 wherein moving the probe tip into contact with the lamella comprises moving the probe tip until it makes contact with the lamella and then moving the probe forward to push the sample and break any remaining connection between the lamella and the substrate. 3. The method of claim 1 wherein moving the microprobe so that the sample is in contact with a desired position on a sample holder comprises moving the microprobe so that the sample is in contact with a desired position on a sample holder and then turning off the vacuum through the microprobe tip so that the sample is released from the microprobe tip. 4. The method of claim 3 further comprising applying a positive pressure through the microprobe after the sample is placed at the desired position on the sample holder. 5. The method of claim 1 in which the lamella has a substantially vertical sample face and in which moving a microprobe into contact with the lamella comprises:positioning the substrate relative to a microprobe having a cylindrical axis so that the cylindrical axis lies in a plane which is perpendicular to the sample face, said microprobe connected to a micromanipulator and mounted onto a probe stage that can rotate about the cylindrical axis of the probe, said microprobe having a generally flat tip which is beveled at an oblique tip angle with respect to the cylindrical axis of the microprobe; and said microprobe oriented so that the cylindrical axis of the microprobe is at an oblique probe angle with respect to the sample face and so that the beveled probe tip is substantially parallel to the sample face; andmoving the microprobe so that the flat tip of the probe tip is in contact with the sample face. 6. The method of claim 5 in which moving the probe so that the sample is in contact with a desired position on a sample holder comprises:rotating the probe around its cylindrical axis through a first rotational angle so that the face of the beveled probe tip and the sample face are substantially parallel to the surface of a sample holder;positioning the probe so that the sample is generally above a desired position on the sample holder; andlowering the probe until the sample comes in contact with the surface of the sample holder. 7. The method of claim 5 in which the probe angle is 45 degrees, the tip angle is 45 degrees, and the first rotational angle is 180 degrees. 8. The method of claim 1 in which extracting the sample does not take place inside an ion beam system. 9. The method of claim 1 further comprising, after placing the substrate with the lamella to be extracted on a moveable stage, moving the stage so that the approximate x-y coordinates of a lamella to be extracted are within the field of view of an optical microscope;directing a light source at the lamella at an acute angle relative to the substrate surface;rotating the stage so that the illumination from the light source is directed in a plane perpendicular to the vertical face of the lamella; andusing computer-based image recognition software to identify the precise location of the lamella. 10. A method for extracting a sample from a substrate, the method comprising:mounting the substrate with the sample to be extracted on a moveable stage, the sample having a planar face to be used as a probe attachment site;positioning the substrate relative to a microprobe having a cylindrical axis so that the cylindrical axis lies in a plane which is perpendicular to the sample face, said microprobe connected to a micromanipulator and mounted onto a probe stage that can rotate about the cylindrical axis of the probe, said microprobe having a generally flat tip which is beveled at an oblique tip angle with respect to the cylindrical axis of the microprobe; and said microprobe oriented so that the cylindrical axis of the microprobe is at an oblique probe angle with respect to the substrate surface and so that the beveled probe tip is substantially parallel to the sample face;moving the microprobe so that the microprobe tip comes into contact with a vertical face on the sample, the sample being physically connected to the substrate;lifting the microprobe with attached sample away from the substrate, severing the connection between the sample and the substrate;rotating the probe around its cylindrical axis through a first rotational angle so that the face of the beveled probe tip and the sample face are substantially parallel to the surface of a sample holder;positioning the probe so that the sample is generally above a desired position on the sample holder;lowering the probe until the sample comes in contact with the sample holder;depositing the sample onto the sample holder;moving the probe away from the released sample. 11. The method of claim 10 wherein said planar face is at a first sample angle relative to the substrate surface and wherein the combination of the tip angle and the probe angle equal the angle of the planar face. 12. The method of claim 10 further comprising applying a vacuum to the microprobe through an open microprobe tip so that the vacuum holds the sample against the microprobe tip. 13. The method of claim 10 further comprising, after placing the substrate with the sample to be extracted on a moveable stage, moving the stage so that the approximate x-y coordinates of the sample to be extracted are within the field of view of an optical microscope;directing a light source at the sample at an acute angle relative to the substrate surface;rotating the stage so that the illumination from the light source is directed in a plane perpendicular to the planar face of the sample; andusing computer-based image recognition software to identify the precise location of the sample. 14. The method of claim 1 in which severing the attachment between the sample and the substrate does not take place inside an ion beam system. 15. The method of claim 1 further comprising determining if a lamella is present using a light source positioned at an oblique angle with respect to the substrate surface to illuminate the lamella. |
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abstract | The present invention quickly resolves troubles in an analyzer and performs effective external quality control management. An analyzer (2) and a control device (1) are connected by a network (3). Error data and sample data taken from an assay of a quality control substance are transmitted from the control device (1) to the analyzer (2). The analyzer (2) is made to be remotely operable from the control device (1) and when problems arise, repair from the control device (1) is possible. The control device (1) tallies sample data and provides the tally results to a Web page. The analyzer (2) accesses the Web page using a WWW browser, and it can perform external quality control in real time. |
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062367102 | abstract | A curved crystal x-ray optical device consists of a doubly curved crystal lamella attached by a thick bonding layer to a backing plate that provides for prepositioning it in three dimensions relative to a source and image position in x-ray spectrometers, monochromators and point-focussing x-ray focusing instruments. The bonding layer has the property of passing from a state of low viscosity to high viscosity by polymerization or by a temperature change. In fabrication, the crystal lamella is bent so that its atomic planes are curved to a radius of 2R.sub.1 in a first plane where R.sub.1 is the radius of a focal circle and R.sub.2 in a second plane perpendicular to the first plane by forcing it to conform to the surface of a doubly curved convex mold using pressure produced in the highly viscous bonding material by force applied to the backing plate. |
044366914 | abstract | An inductive method and apparatus for forming detached spheromak plasma using a thin-walled metal toroidal ring, with external current leads and internal poloidal and toroidal field coils located inside a vacuum chamber filled with low density hydrogen gas and an external axial field generating coil. The presence of a current in the poloidal field coils, and an externally generated axial field sets up the initial poloidal field configuration in which the field is strongest toward the major axis of the toroid. The internal toroidal-field-generating coil is then pulsed on, ionizing the gas and inducing poloidal current and toroidal magnetic field into the plasma region in the sleeve exterior to and adjacent to the ring and causing the plasma to expand away from the ring and toward the major axis. Next the current in the poloidal field coils in the ring is reversed. This induces toroidal current into the plasma and causes the poloidal magnetic field lines to reconnect. The reconnection continues until substantially all of the plasma is formed in a separated spheromak configuration held in equilibrium by the initial external field. |
claims | 1. ATFT array inspecting apparatus comprising:a vacuum chamber;a stage disposed in the vacuum chamber so that a TFT array to be inspected is disposed on the stage;an electron gun opposite to the stage in the vacuum chamber to generate an electron beam onto the TFT array;an electron detecting unit to detect secondary electrons emitted from the TFT array in response to the electron beam of the electron gun; andat least one elevating unit to move the TFT array to a position between a level position and an inclined position having a designated angle with the level position, the position varying according to a size of the TFT array. 2. The TFT array inspecting apparatus as set forth in claim 1, wherein the electron gun is disposed above the vacuum chamber, the stage is disposed at a lower part of the vacuum chamber, and the elevating unit is disposed at a first end of the stage. 3. The TFT array inspecting apparatus as set forth in claim 2, further comprising:a stopper provided at a second end of the stage to protrude upward,wherein the TFT array is moved into the inclined position when a first end of the TFT array is lifted by the elevating unit while a second end of the TFT array is caught by the stopper. 4. The TFT array inspecting apparatus as set forth in claim 3, wherein the electron detecting unit is vertically installed above the stopper to detect the secondary electrons emitted from the TFT array. 5. The TFT array inspecting apparatus as set forth in claim 1, wherein the elevating unit is a hydraulic cylinder type. 6. The TFT array inspecting apparatus as set forth in claim 1, further comprising:a lens unit to set an irradiating position of the electron beam; anda deflection unit disposed in front of the electron gun to deflect the electron beam passing through the lens unit. 7. A TFT array inspecting apparatus comprising:a vacuum chamber vacuumed by a vacuum pump;an electron gun to generate an electron beam onto a TFT array disposed in the vacuum chamber;an electron detecting unit to detect secondary electrons emitted from the TFT array in response to the electron beam of the electron beam; andat least one elevating unit to move the TFT array to a position between a level position and an inclined position having a designated angle with the level position, the position varying according to a size of the TFT array. 8. The TFT array inspecting apparatus as set forth in claim 7, wherein the electron gun is disposed above the vacuum chamber, the TFT array is disposed at a lower part of the vacuum chamber, and the elevating unit is disposed at a first end of the TFT array to elevate an end of the TFT array. 9. The TFT array inspecting apparatus as set forth in claim 8, wherein the electron detecting unit is vertically installed above a second end of the TFT array to detect the secondary electrons emitted from the TFT array. 10. The TFT array inspecting apparatus as set forth in claim 7, further comprising:a lens unit to set an irradiating position of the electron beam; anda deflection unit disposed in front of the electron gun to deflect the electron beam passing through the lens unit. 11. A transistor array inspecting apparatus comprising:a vacuum chamber;an electron gun to generate an electron beam onto a transistor array disposed in the vacuum chamber;an electron detecting unit to detect secondary electrons emitted from the transistor array in response to the electron beam of the electron beam; andat least one elevating unit to change a relative position between the transistor array and at least one of the electron gun and the electron detecting unit, the position varying according to a size of the transistor array, so that it is determined whether the transistor array is defective according to the detected secondary electrons. 12. The transistor array inspecting apparatus as set forth in claim 11, wherein the vacuum chamber comprises a bottom, and the at least one elevating unit comprises:a main body; anda piston rod connected to the main body to elevate the transistor array with respect to the bottom. 13. The transistor array inspecting apparatus as set forth in claim 12, wherein the main body is disposed outside the vacuum chamber, and the piston rod passes through a hole formed on the bottom of the vacuum chamber to elevate the transistor array. 14. The transistor array inspecting apparatus as set forth in claim 12, further comprising:a stopper disposed in the vacuum chamber,wherein the piston rod elevates a first end of the transistor array, and the stopper supports a second end of the transistor. 15. The transistor array inspecting apparatus as set forth in claim 11, further comprising:a stage on which the transistor array is disposed within the vacuum chamber,wherein the at least one elevating unit elevates the transistor array with respect to the stage. 16. The transistor array inspecting apparatus as set forth in claim 11, wherein the vacuum chamber comprises a bottom, and the electron gun and the electron detecting unit are fixedly connected to the vacuum chamber while the at least one elevating unit controls the transistor array to rotate with respect to the bottom according to the relative position. 17. The transistor array inspecting apparatus as set forth in claim 11, wherein the vacuum chamber comprises a bottom, and the at least one elevating unit controls the transistor array to move to a position having an angle with the bottom according to the relative position. 18. The transistor array inspecting apparatus as set forth in claim 11, wherein the transistor array has one of a first surface area and a second surface area to receive the electron beam and emit the secondary electrons, and the at least one elevating unit controls the transistor array to move to the relative position so that the second surface area has the same effective area as the first surface area with respect to a bottom of the vacuum chamber to correspond to the electron gun and the electron detecting unit. 19. The transistor array inspecting apparatus as set forth in claim 11, wherein the transistor array comprises a first transistor array having a first surface area and a second transistor array having a second surface area larger than the first surface area, and the at least one elevating unit controls the first transistor array to be disposed in a level position and the second transistor array to move an inclined position having an angle with the level position so that the first surface area of the first transistor array and the second surface of the second transistor array have a same effective area with respect to the electron gun and the electron detecting unit. 20. The transistor array inspecting apparatus as set forth in claim 11, wherein the transistor array comprises a first transistor array having a first surface area and a second transistor array having a second surface area larger than the first surface area, and the first surface area of the first transistor array and the second surface of the second transistor array are irradiated by the electron gun using the electron beam and detected by the electron detecting unit using the secondary electrons according to the relative position. 21. The transistor array inspecting apparatus as set forth in claim 11, wherein the at least one elevating unit moves the transistor array with respect to the electron gun and the electron detecting unit according to the relative position to inspect the transistor array regardless of an area of a surface of the transistor array to be inspected. 22. A TFT array inspecting apparatus comprising:a vacuum chamber;a stage disposed in the vacuum chamber so that one of a first TFT array and a second TFT to be inspected is disposed on the stage;an electron gun opposite to the stage in the vacuum chamber to generate an electron beam onto the one of the first TFT array and the second TFT array;an electron detecting unit to detect secondary electrons emitted from the one of the first TFT array and the second TFT array in response to the electron beam of the electron gun; andat least one elevating unit to move the stage to a first position and a second position with respect to a level position according to a first length of the first TFT array and a second length of the second TFT array such that the first TFT array and the second TFT array disposed on the stage at the first position and the second position, respectively, have a same effective length with respect to the level position. |
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046366458 | summary | BACKGROUND OF THE INVENTION The present invention relates to the long-term storage of spent fuel that has been removed from a nuclear reactor, and more particularly, to a closure system which can be removeably applied to a spent fuel storage cask during development, testing, and demonstration of the cask and which can also be used to permanently seal the cask during long-term storage, after the development, testing, and demonstration have been completed. FIG. 1 illustrates a typical fuel assembly 20 for supplying nuclear fuel to a reactor. Assembly 20 includes a bottom nozzle 22 and a top nozzle 24, between which are disposed elongated fuel rods 26. Each fuel rod 26 includes a cylindrical housing made of a zirconium alloy such as commercially available "Zircalloy-4", and is filled with pellets of fissionable fuel enriched with U-235. Within the assembly of fuel rods 26, tubular guides (not shown) are disposed between nozzles 22 and 24 to accommodate movably mounted control rods (not illustrated) and measuring instruments (not illustrated). The ends of these tubular guides are attached to nozzles 22 and 24 to form a skeletal support for fuel rods 26, which are not permanently attached to nozzles 22 and 24. Grid members 28 have apertures through which fuel rods 26 and the tubular guides extend to bundle these elements together. Commercially available fuel assemblies for pressurized water reactors include between 179 and 264 fuel rods, depending upon the particular design. A typical fuel assembly is about 4.1 meters long, about 19.7 cm wide, and has a mass of about 585 kg., but it will be understood that the precise dimensions vary from one fuel assembly design to another. After a service life of about three years in a pressurized water reactor, the U-235 enrichment of a fuel assembly 20 is depleted. Furthermore, a variety of fission products, having various half-lives, are present in rods 26. These fission products generate intense radioactivity and heat when assemblies 20 are removed from the reactor, and accordingly the assemblies 20 are moved to a pool containing boron salts dissolved in water for short-term storage. Such a pool is designated by reference number 30 in FIG. 2. Pool 30 is typically 12.2 meters deep. A number of spent fuel racks 32 positioned at the bottom of pool 30 are provided with storage slots 34 to vertically accommodate fuel assemblies 20. A cask pad 36 is located at the bottom of pool 30. During the period when fuel assemblies 20 are stored in pool 30, the composition of the spent fuel in rods 26 changes. Isotopes with short half-lives decay, and consequently the proportion of fission products having relatively long half-lives increases. Accordingly, the level of radioactivity and heat generated by a fuel assembly 20 decreases relatively rapidly for a period and eventually reaches a state wherein the heat and radioactivity decrease very slowly. Even at this reduced level, however, rods 26 must be reliably isolated from the environmnet for the indefinite future. Dry storage casks provide one form of long-term storage for the spent fuel. After the heat generated by each fuel assembly 20 falls to a predetermined level--such as 0.5 to 1.0 kilowatt per assembly, after perhaps 10 years of storage in pool 30--an opened cask is lowered to pad 36. The cask typically contains a basket arrangement which provides a matrix of vertically oriented storage slots for receiving spent fuel. By remote control the spent fuel (either in the form of fuel assemblies 20 or in the form of consolidation canisters which contain fuel rods 26 that have been removed from fuel assemblies in order to increase storage density) is transferred to the basket arrangement in the cask, which is then sealed, drained, and flooded with a gas. The cask can then be removed from pool 30 and transported to an above-ground storage area for long-term storage. The requirements which must be imposed on such a cask are rather severe. The cask must be immune from chemical attack during long-term storage. Furthermore, it must be sufficiently rugged mechanically to avoid even tiny ruptures or fractures during long-term storage and during transportation, when the cask might be subjected to rough treatment or accidents such as drops. Moreover, the cask must be able to transmit heat generated by the spent fuel to the environment while nevertheless shielding the environment from radiation generated by the spent fuel. The temperature of the rods 26 must be kept below a maximum temperature, such as 375.degree. C., to prevent deterioration of the zirconium alloy housing. The basket arrangement in the cask must be able to mechanically support the spent fuel under all realistic conditions while transferring heat generated by the spent fuel to the cask walls. Provisions must also be made to ensure that a chain reaction cannot be sustained within the cask before the water is drained. These requirements impose stringent demands upon the cask, which must fulfill its storage function in an utterly reliable manner. In view of these demands it is not surprising that a considerable amount of development, testing, and refinement is warranted before a cask is ready for commercial production. It might be desirable to empirically confirm calculations concerning radiation levels or temperature, for example, or to test a new basket arrangement in actual practice. In a similar manner it might be desirable to check the internal condition of the cask or the fuel after a period of storage, or to test cask performance under different storage modes (i.e., intact fuel assemblies or consolidated fuel). In short, it will be apparent that it is desirable, during development, testing, and demonstration of a cask, to seal the cask with a removeable closure system in order to permit access to the cask interior. Nevertheless the object of this testing and refinement is to develop a cask which can be permanently sealed for a long-term storage of spent fuel. Moreover the closure system itself is part of what is tested; that is, it is desirable to test the cask using the closure system which will be used in actual practice. SUMMARY OF THE INVENTION Accordingly, one object of the present invention is to provide a closure system which can be removeably applied during development, testing, and demonstration of a cask and which can thereafter be permanently applied, without re-designing either the cask or the closure system, when the cask is used for long-term storage of spent nuclear fuel. Another object of the present invention is to provide a closure system which employs redundant seals both during the developmental period and during long-term storage. Another object of the present invention is to provide a closure system which uses mechanical seals during development of the cask but which permits the employment of welded seals during long-term storage. These and other objects are attained by providing a closure system having a primary cover and a secondary cover which are installed in a cask base element having a stepped mouth region. The primary cover is placed in the stepped mouth region while the cask base element remains in the pool, and its weight compresses a mechanical seal such as a O-ring. The primary cover attenuates radiation sufficiently to permit workers to have brief access to the cask, and shear keys are inserted into a groove in the mouth region of the cask to ensure that the primary cover does not become dislodged as the cask is raised from the pool prior to installation of the secondary cover. If the cask is to be permanently sealed, the shear keys are removed sequentially while a canopy-type welded seal is applied around the periphery of the primary cover. Regardless of whether the cask is to be installed permanently or temporarily, a secondary cover cooperating with a mechanical seal is bolted above the primary cover. If the cask is to be permanently sealed, a canopy-type welded seal is provided at the periphery of the secondary cover. |
044938136 | summary | BACKGROUND OF THE INVENTION The present invention relates to an upper neutron protection device for a nuclear reactor assembly and more particularly for fast neutron reactors. In such reactors, it is necessary to limit the activation of the secondary sodium passing through the heat exchangers and to reduce damage to the various primary components, particularly the reactor vessels. The standard method consists of confining the neutrons in the central area of the core, by placing on the periphery thereof assemblies only containing fertile material in order to absorb the neutrons and also by placing fertile material in the upper and lower parts of the fuel assemblies, on either side of the fissile material. The protection is completed by so-called "upper neutron protection" sleeves, positioned in the upper part of the assemblies. In most existing systems, each assembly comprises in the upper part a head in the form of a sleeve and in the lower part a foot, which are disposed on either side of the assembly. The sleeve has a greater thickness than the assembly and the space provided in its central part makes it possible to circulate the cooling fluid, e.g. liquid sodium, from bottom to top through the assembly. However, it is known that the assemblies have to be replaced in the core and this takes place for each loading campaign of the latter, as a function of the irradiation undergone. Each spent assembly must be removed from the core and is then passed to a reprocessing installation, where the head, assembly and foot are separated from the needles or rods. As a result the sleeve is lost on each occasion, because it is fixed to the body of the assembly. Devices have also been proposed which have a removable sleeve, but the latter have a considerable wall thickness and often the fixing devices are complex, which increases the cost of the equipment and complicates disassembly. BRIEF SUMMARY OF THE INVENTION The present invention relates to a device obviating the aforementioned disadvantages, whilst being simple to construct and easy to disassemble, during the dismantling of the irradiated assembly. According to the main feature of the upper neutron protection device according to the invention, the latter comprises a container, at least partly filled with a neutron-absorbing product, held in place with the aid of at least one spacing plate, the assembly constituted by the container and the spacing plates being located within a wall positioned in the upper part of the assembly body. According to another feature of the invention, each of the aforementioned spacing plates has an outer edge, whereof at least part is substantially rectilinear and an inner edge, whereof at least part matches the shape of the container. Two types of spacing plates are used in the device according to the invention. In the first type, called male spacing plates, the upper part projects beyond the top of the assembly body, has an outer edge which slopes from top to bottom towards the outside of the wall surrounding the device and has a slot opening towards the outside of the wall and permitting the attachment of a handling means. In the other type, called female spacing plates, they are level with the top of the assembly body and have at least one portion of the upper part of their inner edge which slopes from top to bottom towards the inside of the space defined by the aforementioned wall and, still in the upper part of their inner edge, a slot opening towards the inside of said space and which also makes it possible to attach a handling means. These two types of plates prevent the inadvertent blocking of an assembly by another assembly during handling. Finally, according to a special embodiment of the invention, the device has a plurality of containers, at least partly filled with a neutron-absorbing product, each of the containers being held in place by a single spacing plate. |
claims | 1. A measuring and testing complex for carrying out researches in an X-ray range of radiation on multiple analytical stations simultaneously, each analytical station being configured for performing predetermined measurements or tests, the complex comprising:a single non-synchrotron radiation source for producing X-rays in a form of a single divergent beam,multiple radiation transporting channels for transporting radiation from the single non-synchrotron radiation source to the respective multiple analytical stations, andmultiple X-ray lenses corresponding to the multiple analytical stations, each of the X-ray lenses having a number of bent channels configured to provide multiple total external reflection of X-rays from walls of the bent channels,each of the X-ray lenses being configured to extract a part of the single divergent beam produced by the radiation source and transform the part the single divergent beam into a quasi-parallel beam,each of the radiation transporting channels being configured to include one of the X-ray lenses and to provide propagation of the extracted part of the single divergent beam and the quasi-parallel beam in an air medium to an input aperture of the corresponding analytical station. 2. The complex according to claim 1, wherein a distance between the analytical station and the corresponding X-ray lens being selected so as to provide a predetermined distance between quasi-parallel beams provided by different radiation transporting channels in an area adjacent the analytical station. 3. The complex according to claim 1, wherein the non-synchrotron radiation source includes an X-ray tube. 4. The complex according to claim 1, wherein the non-synchrotron radiation source includes a plasma X-ray source. 5. The complex according to claim 1, wherein the non-synchrotron radiation source includes a laser X-ray source. 6. The complex according to claim 1, wherein at least one of the analytical stations is configured for carrying out diffractometry researches and comprises:means for placing and orienting a sample under study with respect to the quasi-parallel beam, which is directed to the input aperture of the analytical station,a detector of radiation diffracted on the sample under study,means for positioning the detector and the sample under study relative to each other, andmeans for data processing and imaging responsive to an output of the detector. 7. The complex according to claim 1, wherein at least one of the analytical stations is configured for image formation of an internal structure of a sample and comprises:means for positioning the sample,a detector of radiation passed through the sample, andmeans for visualizing and registering an image. 8. The complex according to claim 1, wherein at least one of the analytical stations is configured for carrying out X-ray lithography and comprises:means for positioning a mask, andmeans for placing a substrate with a layer of resist applied on it,the means for placing is arranged behind the means for positioning the mask. 9. The complex according to claim 1, wherein at least one of the analytical stations is configured for carrying out spectrometric researches and comprises:a further X-ray lens having a number of bent channels configured to provide multiple total external reflection of X-rays from walls of the bent channels, the further X-ray lens is configured to provide radiation focusing of the quasi-parallel beam,means for positioning a sample under study in order to align a required portion of the sample with a region of X-rays focusing,a detector of radiation excited in the sample under study,a spectrometric channel coupled to an output of the detector, andmeans for data processing and imaging responsive to an output of the spectrometric channel. 10. A measuring and testing complex for carrying out researches in an X-ray range of radiation on multiple analytical stations simultaneously, each analytical station being configured for performing predetermined measurements or tests, the complex comprising:a single non-synchrotron radiation source for producing divergent X-rays,multiple radiation transporting channels for transporting radiation from the single non-synchrotron radiation source to the respective multiple analytical stations,an X-ray lens having a number of bent channels configured to provide multiple total external reflection of X-rays from walls of the bent channels,the X-ray lens being configured to extract a part of the divergent X-rays produced by the radiation source and transform the part the divergent X-rays into a quasi-parallel beam,multiple monochromators arranged so as to extract and reflect different parts of the quasi-parallel beam,the X-ray lens being common for the multiple radiation transporting channels configured to provide propagation of the extracted part of the divergent X rays and the quasi-parallel beam,the multiple radiation transporting channels being further configured to include said multiple monochromators and to provide propagation of the different parts of the quasi-parallel beam extracted and reflected by the monochromators in an air medium to input apertures of the respective analytical stations. 11. The complex according to claim 10, wherein the non-synchrotron radiation source includes an X-ray tube. 12. The complex according to claim 10, wherein at least one of the analytical stations is configured for carrying out diffractometry researches and comprises:means for placing and orienting a sample under study with respect to the quasi-parallel beam, which is directed to the input aperture of the analytical station,a detector of radiation diffracted on the sample under study,means for positioning the detector and the sample under study relative to each other, andmeans for data processing and imaging responsive to an output of the detector. 13. The complex according to claim 10, wherein at least one of the analytical stations is configured for image formation of an internal structure of a sample and comprises:means for positioning the sample,a detector of radiation passed through the sample, andmeans for visualizing and registering an image. 14. The complex according to claim 10, wherein at least one of the analytical stations is configured for carrying out X-ray lithography and comprises:means for positioning a mask, andmeans for placing a substrate with a layer of resist applied on it,the means for placing is arranged behind the means for positioning the mask. 15. The complex according to claim 10, wherein at least one of the analytical stations is configured for carrying out spectrometric researches and comprises:a further X-ray lens having a number of bent channels configured to provide multiple total external reflection of X-rays from walls of the bent channels, the further X-ray lens is configured to provide radiation focusing of the quasi-parallel beam,means for positioning a sample under study in order to align a required portion of the sample with a region of X-rays focusing,a detector of radiation excited in the sample under study,a spectrometric channel coupled to an output of the detector, andmeans for data processing and imaging responsive to an output of the spectrometric channel. |
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claims | 1. A charged particle irradiation system comprising:an accelerator from which a charged particle beam is extracted;an irradiation unit that has a charged particle beam scanning unit and irradiates an irradiation spot with the charged particle beam extracted from the accelerator; anda control unit configured to, when an event that causes the irradiation to be interrupted occurs during the irradiation of the irradiation spot with the charged particle beam, continue the extraction of the charged particle beam from the accelerator until the irradiation of all spots of a spot group including a plurality of spots reach target doses; andstop the extraction of the charged particle beam from the accelerator at the time of completion of the irradiation of all spots that belong to the spot group,wherein, the spot group is predefined and includes a plurality of spots, including the irradiation spot. 2. The charged particle irradiation system according to claim 1,wherein when the event that causes the irradiation to be interrupted is eliminated after stopping the extraction of the charged particle beam, the control unit immediately changes the irradiation spot and restarts the extraction of the charged particle beam from the accelerator so that irradiation is performed from a first spot of a next spot group. 3. The charged particle irradiation system according to claim 1,wherein said spot group includes a first spot group and a second spot group that are predefined such that the first and second spot groups comprise overlapping spots belonging to both of the first and second spot groups, andsaid control unit stops the extraction of the charged particle beam from the accelerator at the time of completion of the irradiation of all spots that belong to the first spot group even when said event occurs. 4. A charged particle irradiation system comprising:an accelerator from which a charged particle beam is extracted;an irradiation unit that has a charged particle beam scanning unit and irradiates, with the charged particle beam extracted from the accelerator, an irradiation spot that is a spot to be irradiated;a first control unit configured to stop the extraction of the charged particle beam from the accelerator when a dose of the charged particle beam with which the irradiation spot is irradiated reaches a target dose,control the charged particle beam scanning unit to cause the charged particle beam scanning unit to change the irradiation spot a next irradiation spot, that is a spot to be irradiated next to the irradiation spot, under the condition that the extraction of the charged particle beam is stopped,and restart the extraction of the charged particle beam from the accelerator after the charged particle beam scanning unit changes the irradiation spot to the next irradiation spot; anda second control unit configured to, when an event that causes the irradiation to be interrupted occurs during the irradiation of the irradiation spot with the charged particle beam, continuously control the first control unit until the dose of the charged particle beam with which the irradiation spot is irradiated reaches the target dose,continuously control the first control unit in order to irradiate the next irradiation spot when the dose of the charged particle beam with which the irradiation spot is irradiated reaches the target dose, andinterrupt the control of the first control unit and stop the extraction of the charged particle beam from the accelerator at the time of completion of the irradiation of all spots that belong to a spot group, such that even when said event occurs the irradiation is continued until all spots of the spot group reach target doses,wherein the spot group is predefined and includes a plurality of spots, including the irradiation spot, and the next irradiation spot. 5. The charged particle irradiation system according to claim 4,wherein when the event that causes the irradiation to be interrupted is eliminated after the stop of the extraction of the charged particle beam, the second control unit causes the first control unit to recover the control that stops the extraction of the charged particle beam from the accelerator, controls the charged particle beam scanning unit and restarts the extraction of the charged particle beam from the accelerator,after the recovery of the control, the first control unit immediately controls the charged particle beam scanning unit so that the charged particle beam scanning unit changes the irradiation spot and restarts the extraction of the charged particle beam from the accelerator after the change of the irradiation spot so as to perform irradiation from a first spot of a next spot group. 6. The charged particle irradiation system according to claim 4,wherein said spot group includes a first spot group and a second spot group that are predefined such that the first and second spot groups comprise overlapping spots belonging to both of the first and second spot groups, andsaid second control unit stops the extraction of the charged particle beam from the accelerator at the time of completion of the irradiation of all spots that belong to the first spot group even when said event occurs. 7. A method for controlling a charged particle irradiation system that includes an accelerator from which a charged particle beam is extracted, and an irradiation unit that has a charged particle beam scanning unit and irradiates an irradiation spot in a spot group that is predefined and includes a plurality of spots, including the irradiation spot, with the charged particle beam extracted from the accelerator, the method comprising the steps of:when an event that causes the irradiation to be interrupted occurs during the irradiation of the irradiation spot with the charged particle beam, continuing the extraction of the charged particle beam from the accelerator until the irradiation of all spots of the spot group reach target doses,stopping the extraction of the charged particle beam from the accelerator at the time of completion of irradiation of all spots that belong to the spot group. 8. The method according to claim 7, further comprising the steps of, when the event that causes the irradiation to be interrupted is eliminated after the stop of the extraction of the charged particle beam, immediately changing the irradiation spot and restarting the extraction of the charged particle beam from the accelerator so that irradiation is performed from a first spot of a next spot group. 9. A method for controlling a charged particle irradiation system that includes an accelerator from which a charged particle beam is extracted, and an irradiation unit that has a charged particle beam scanning unit and irradiates an irradiation spot in a spot group that is predefined and includes a plurality of spots, including an irradiation spot and a next irradiation spot, with the charged particle beam extracted from the accelerator, the method comprising:a first step of stopping the extraction of the charged particle beam from the accelerator when a dose of the charged particle beam with which the irradiation spot is irradiated reaches a target dose, controlling the charged particle beam scanning unit to cause the charged particle beam scanning unit to change the irradiation spot to the next irradiation spot, that is a spot to be irradiated next to the irradiation spot, under the condition that the extraction of the charged particle beam is stopped, and restarting the extraction of the charged particle beam from the accelerator after the change of the irradiation spot to the next irradiation spot; anda second step of, when an event that causes the irradiation to be interrupted has occurred during the irradiation of the irradiation spot with the charged particle beam, continuously extracting the charged particle beam until the dose of the charged particle beam with which the irradiation spot is irradiated reaches the target dose, and controlling the charged particle beam scanning unit to cause the charged particle beam scanning unit to change the irradiation spot to the next irradiation spot, that is a spot to be irradiated next to the irradiation spot when the dose of the charged particle beam with which the irradiation spot is irradiated reaches the target dose; anda third step of continuously repeating the second step with the next irradiation spot as the irradiation spot until completing the irradiation of all spots that belong to the spot group and then interrupting the second step and stopping the extraction of the charged particle beam from the accelerator at the time of completion of the irradiation of all spots that belong to the spot group, such that even when said event occurs the irradiation is continued until all spots of the spot group reach target doses. 10. The method according to claim 9,wherein the second step or third step restarts the first step when the event that causes the irradiation to be interrupted is eliminated after the stop of the extraction of the charged particle beam, andin the first step, the charged particle beam scanning unit is controlled immediately after the restart of the first step to change the irradiation spot to the next spot, and the extraction of the charged particle beam from the accelerator is restarted after the change of the irradiation spot so that irradiation is performed from a first spot of a next spot group. |
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abstract | The invention relates to a method for transferring an article from a fluid-filled first vessel into a fluid-filled second vessel or in the opposite direction. The vessel is connected by a connecting element, in which there is a transport device for moving the article. A fluid flow flowing out of the first vessel is maintained in one part of the connecting element, while the article is transported through the connecting element. An apparatus for transferring an article, in particular a nuclear fuel element, between the vessels is also described, in which an extraction device for the discharge of fluid is located on the connecting element. |
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abstract | A system for carrying out fibered multiphoton microscopic imagery of a sample (10) for use in endoscopy or fluorescence microscopy includes: a femtosecond pulsed laser (1, 2) for generating a multiphoton excitation laser radiation; an image guide (8) having a number of optical fibers and permitting the sample to be illuminated by a point-by-point scanning in a subsurface plane; pre-compensating elements (4) for pre-compensating for dispersion effects of the excitation pulses in the image guide (8), these elements being situated between the pulsed laser and the image guide (8); scanning elements for directing, in succession, the excitation laser beam in a fiber of the image guide, and; in particular, an optical head (9) for focussing the excitation laser beam exiting the image guide in the sample (10). |
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041525850 | summary | BACKGROUND OF THE INVENTION The present invention concerns an assembly for the transport and storage of radioactive fuel elements. For the conveyance of fuel elements it is known to use sealably closed transportation flasks. During conveyance irradiated fuel elements are submerged in liquid (for example water) within the flask to dissipate heat generated by the decay of fission products and thereby limit the fuel temperature. While provision must be made for change of volume of the liquid in the flask, it is important that irradiated fuel elements are submerged at all times during conveyance. In British Pat. Specification No. 1378681 there is described and claimed a sealably closable fuel element transportation canister for containing fuel elements submerged in liquid having self-regulating ullage means arranged so that within a chamber for containing the fuel elements the free space can be maintained full of liquid. In particular there is described a canister having a primary chamber for containing the fuel elements submerged in liquid, a secondary chamber for containing liquid and pressurised gas and a duct interconnecting the chambers and arranged for forming an air lock there between whereby the free space in the primary chamber can be maintained full of liquid. It is now considered that it is not necessary for the chamber containing the fuel elements to be full of liquid although there must be sufficient liquid in the chamber for the fuel elements always to be submerged in the liquid. This condition is important for transportation flasks in which the fuel elements are loaded into the flask in one orientation and the flask is transported in a second orientation. SUMMARY OF THE INVENTION Accordingly the present invention provides an assembly for the transport and storage of radioactive fuel elements, comprising a transport flask and a fuel element holder disposed in the flask so that fuel elements in the holder may be submerged in liquid within the flask and the assembly may be used in one orientation for loading the fuel elements and in another orientation for transporting the fuel elements, the assembly having self-regulating ullage means comprising reservoirs for containing liquid and a pressurised gas and the arrangement of the reservoirs being such that in either orientation of the assembly liquid is maintained in all the reservoirs to prevent egress of the pressurised gas therein and to compensate for volume changes arising from temperature variations within the flask. In a preferred arrangement elongate reservoirs are provided around the fuel element holder. The reservoirs may each have two communications between the interior and exterior of the reservior, the first of the communications being at the end of the reservior which is lowermost when the assembly is in a vertical position used for loading and being so placed that it is below the level of the liquid in the reservoir when the assembly is in a horizontal position used for transport, the second communication comprising a tube extending from said lowermost end of the reservoir to a point of opening which is above the level of liquid in the reservoir in the vertical position of the assembly used for loading but below the level of liquid in the reservoir or reservoirs in the horizontal position of the assembly used for transport, the tube being shaped to prevent egress of the pressurised gas when the assembly is in the horizontal position. The assembly may include a basket assembly on which the reservoirs are located. The basket assembly receives the fuel elements which may be enclosed within fuel canisters. |
040654001 | claims | 1. A process for continuously solidifying high level radioactive waste resulting from reprocessing irradiated nuclear reactor fuels anc containing virtually all of the nonvolatile fission products, several tenths of one percent of the uranium and plutonium originally in the irradiated fuels, and other actinides formed by transmutation of the uranium and plutonium as normally produced in a nuclear reactor, by using a fluidized inert bed having a minimal fission product inventory comprising introducing an inert particulate material comprising silica particles having an average particle diameter of from about 0.20 to about 0.40 mm into a chamber; heating said material to from about 400.degree. to about 1300.degree. C; dispersing air as a fluidizing gas beneath said material to agitate same and form a fluidized bed; atomizing said radioactive liquid waste; introducing said atomized waste into an upper portion of said heated, fluidized bed to effect calcination of said waste and formation of a fluidized inert bed with said atomized waste comprising from about 10 to about 15 weight percent calcined radioactive waste and from about 90 to 85 weight percent silica particles, a first portion of said calcined waste being spray dried, a second portion of said calcined waste depositing and remaining on said particulate fluidized bed material, and a third portion of said calcined waste depositing on said bed material and attriting therefrom; removing solid calcine radioactive waste from said reactor chamber, said removing comprising elutriating said spray dried first portion, elutriating said attrited third portion, separating said elutriated solid calcine waste from said fluidizing gas, and overflowing said second portion from said fluidized bed at an about upper portion of said fluidized bed, said introducing of said atomized waste at an upper portion of said inert fluidized bed enhancing attrition and minimizing inert bed loss through overflow; introducing additional inert particulate material into said reaction chamber to maintain said inert fluidized bed; continuing said atomizing, calcining and removing of said solidified radioactive waste, and collecting said first, second and third portions removed from said fluidized inert bed as a readily vitrifiable product comprising about 90 weight percent calcined waste and about 10 weight percent silica, and having an average particle diameter of from about 0.1 mm to about 0.3 mm. 2. The process of claim 1 wherein said heating is at from about 400.degree. to about 800.degree. C. 3. The product formed by the process of claim 1. 4. The process of claim 1 wherein said high level radioactive liquid waste comprises from 320 to 575 liters of waste feed obtained from the processing of a metric ton of uranium, said feed materials yield from 80 to 210 grams of calcine per liter of liquid waste, and the concentration of sodium in said feed materials is from 0.01 molar to 1 molar said radioactive liquid waste is atomized at the rate of 20 to 40 liters per hour; and said heating is to a temperature of from about 500.degree. to about 800.degree. C. |
abstract | Apparatuses for reducing or eliminating Type 1 LOCAs in a nuclear reactor vessel. A nuclear reactor including a nuclear reactor core comprising a fissile material, a pressure vessel containing the nuclear reactor core immersed in primary coolant disposed in the pressure vessel, and an isolation valve assembly including, an isolation valve vessel having a single open end with a flange, a spool piece having a first flange secured to a wall of the pressure vessel and a second flange secured to the flange of the isolation valve vessel, a fluid flow line passing through the spool piece to conduct fluid flow into or out of the first flange wherein a portion of the fluid flow line is disposed in the isolation valve vessel, and at least one valve disposed in the isolation valve vessel and operatively connected with the fluid flow line. |
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description | The present invention is described in connection with a once-through steam generator for a nuclear power plant, although these principles are generally applicable to shell and tube heat exchangers in any number of diverse fields of activities. Thus, as shown in FIG. 1 for the purpose of illustration, a once-through steam generator unit 10 comprising a vertically elongated cylindrical pressure vessel or shell 11 closed at its opposite ends by an upper head member 12 and a lower head member 13. The upper head includes an upper tube sheet 14, a primary coolant inlet 15, a manway 16 and a handhole 17. The manway 16 and the handhole 17 are used for inspection and repair during times when the vapor generator unit 10 is not in operation. The lower head 13 includes drain 18, a coolant outlet 20, a handhole 21, a manway 22 and a lower tube sheet 23. The vapor generator 10 is supported on a conical or cylindrical skirt 24 which engages the outer surface of the lower head 13 in order to support the vapor generator unit 10 above structural flooring 25. As hereinbefore mentioned, the overall length of a typical vapor generator unit of the sort under consideration is about 75 feet between the flooring 25 and the upper extreme end of the primary coolant inlet 15. The overall diameter of the unit 10 moreover, is in excess of 12 feet. Within the pressure vessel 11, a lower cylindrical tube shroud wrapper or baffle 26 encloses a bundle of heat exchanger tubes 27, a portion of which is shown illustratively in FIG. 1. In a vapor generator unit of the type under consideration moreover, the number of tubes enclosed within the baffle 26 is in excess of 15,000, each of the tubes having an outside diameter of ⅝ inch. It has been found that Alloy 690 is a preferred tube material for use in vapor generators of the type described. The individual tubes in the bundle 27 each are anchored in respective holes formed in the upper and lower tube sheets 14 and 23 through belling, expanding or seal welding the tube ends within the tubesheets. The lower baffle or wrapper 26 is aligned within the pressure vessel 11 by means of pins (not shown). The lower baffle 26 is secured by bolts (not shown) to the lower tubesheet 23 or by welding to lugs (not shown) projecting from the lower end of the pressure vessel 11. The lower edge of the baffle 26 has a group of rectangular water ports 30 or, alternatively, a single full circumferential opening (not shown) to accommodate the inlet feedwater flow to the riser chamber 19. The upper end of the baffle 26 also establishes fluid communication between the riser chamber 19 within the baffle 26 and annular downcomer space 31 that is formed between the outer surface of the lower baffle 26 and the inner surface of the cylindrical pressure vessel 11 through a gap or steam bleed port 32. A support rod system 28 is secured at the uppermost support plate 45B, and consists of threaded segments spanning between the lower tubesheet 23 and the lowest support plate 45A and thereafter between all support plates 45 up to the uppermost support plate 45B. A hollow toroid shaped secondary coolant feedwater inlet header 34 circumscribes the outer surface of the pressure vessel 11. The header 34 is in fluid communication with the annular downcomer space 3135 through an array of radially disposed feedwater inlet nozzles 35. As shown by the direction of the FIG. 1 arrows, feedwater flows from the header 34 into the vapor generating unit 10 by way of the nozzles 35 and 36. The feedwater is discharged from the nozzles downwardly through the annular downcomer 31 and through the water ports 30 into the riser chamber 19. Within the riser chamber 19, the secondary coolant feedwater flows upwardly within the baffle 26 in a direction that is counter to the downward flow of the primary coolant within the tubes 27. An annular plate 37, welded between the inner surface of the pressure vessel 11 and the outer surface of the bottom edge of an upper cylindrical baffle or wrapper 33 insures that feedwater entering the downcomer 31 will flow downwardly toward the water ports 30 in the direction indicated by the arrows. The secondary fluid absorbs heat from the primary fluid through the tubes in the bundle 27 and rises to steam within the chamber 19 that is defined by the baffles 26 and 33. The upper baffle 33, also aligned with the pressure vessel 11 by means of alignment pins (not shown), is fixed in an appropriate position because it is welded to the pressure vessel 11 through the plate 37, immediately below steam outlet nozzles 40. The upper baffle 33, furthermore, enshrouds about one third of the tube bundle 27. An auxiliary feedwater header 41 is in fluid communication with the upper portion of the tube bundle 27 through one or more nozzles 42 that penetrate the pressure vessel 11 and the upper baffle 33. This auxiliary feedwater system is used, for example, to fill the vapor generator 10 in the unlikely event that there is an interruption in the feedwater flow from the header 34. As hereinbefore mentioned, the feedwater, or secondary coolant that flows upwardly through the tube bank 27 in the direction shown by the arrows rises into steam. In the illustrative embodiment, moreover, this steam is superheated before it reaches the top edge of the upper baffle 33. This superheated steam flows in the direction shown by the arrow, over the top of the baffle 33 and downwardly through an annular outlet passageway 43 that is formed between the outer surface of the upper cylindrical baffle 33 and the inner surface of the pressure vessel 11. The steam in the passageway 43 leaves the vapor generating unit 10 through steam outlet nozzles 40 which are in communication with the passageway 43. In this foregoing manner, the secondary coolant is raised from the feed water inlet temperature through to a superheated steam temperature at the outlet nozzles 40. The annular plate 37 prevents the steam from mixing with the incoming feedwater in the downcomer 31. The primary coolant, in giving up this heat to the secondary coolant, flows from a nuclear reactor (not shown) to the primary coolant inlet 15 in the upper head 12, through individual tubes in the heat exchanger tube bundle 27, into the lower head 13 and is discharged through the outlet 20 to complete a loop back to the nuclear reactor which generates the heat from which useful work is ultimately extracted. Referring now to FIG. 2, there is shown a plan view of a portion of a prior art support plate 45 characterized by holes or apertures 46, each of which has at least three inwardly protruding members 47 that restrain but do not all engage or contact the outer surface of the tube 48 extending through the hole 46. Bights 49 that are intermediate of these inwardly protruding members 47 are formed in the individual support plate holes 46 when the associated tube 48 is lodged in place to establish fluid passage through the plate 45. The inwardly protruding members 47 terminate in arcs or arcuate lands 51 that define a circle of a diameter that is only slightly greater than the outside diameter of the associated tube 48. Turning now to prior art FIG. 3, there is shown a plan view of one of the broached holes 46 and a portion of the surrounding support plate 45 of FIG. 2 with a tube 48 inserted through the broached hole 46. A detail of FIG. 3 is shown at FIG. 4 which depicts a problem encountered with this prior art broached hole 46 whereby the sharp edges 50 formed along the vertical sides of the arcuate land 51 of the inwardly protruding member 47 can potentially gouge the outer wall of tube 48 thereby resulting in a faster increase in the depth rate at which through-wall tube wear occurs for a given volume loss. This prior art support plate 45 also allows for a small annular space between the arcuate land 51 and the outer wall of tube 48 and, due to the associated flow restrictions, results in rapidly accumulating detrimental deposits for at least some of the support plates 52. Referring now to FIG. 5, there is shown a plan view of a portion of support plate 52 characterized by holes or apertures 53, each of which has at least three inwardly protruding members 54 that restrain but do not all engage or contact the outer surface of the tube 55 extending through the hole 53. Bights 56 that are intermediate of these inwardly protruding members 54 are formed in the individual support plate holes 53 when the associated tube 55 is lodged in place to establish fluid passage through the plate 52. In accordance with the present invention, the inwardly protruding members 54 terminate in flat lands 57. Turning now to FIG. 6, there is shown a plan view of one of the broached holes 53 of FIG. 5 and a portion of the surrounding support plate 52. A tube 55 extends through the broached hole 53. A detail of FIG. 6 is shown at FIG. 7 where the flat land 57 of the inwardly protruding member 54 provides sufficient tube contact length to lower contact stress thereby minimizing fretting-wear of the tube 55. The flat land configuration also eliminates the potential gouging of the outer wall of tube 55 thus decreasing the depth rate at which through-wall wear occurs for a given volume loss. Moreover, the space between the flat land 57 and the outer wall of tube 55 is increased to reduce deposition accumulation. Referring to FIG. 8, there is shown a plan view of one of the broached holes 53 of FIG. 5 and a portion of the surrounding support plate 52. As shown in FIG. 8 and in FIG. 9 which is a cross-sectional view taken along lines Axe2x80x94A of FIG. 8, the inner wall 58 forming the protruding member 54 in the support plate 52 has an hourglass configuration comprised of a tube contact section 59 with beveled end sections 60. In a tube support plate of the type under consideration, the thickness of the broached plate is 1.5 inches, the length of the tube contact section 59 is 0.75 inches, and the chamfer angle of the beveled end section 60 is 11 degrees. The beveled end sections 60 of the broached holes 53 improve the local fluid flow patterns and reduce the deposition of magnetite and other particles on the support plate 52 due to a decrease in hydraulic shock losses. Computational fluid dynamic modelling of the flow paths through an hourglassed broached hole 53 and experimental testing have confirmed that the gradual contraction and expansion of the fluid flow therethrough effectively reduces pressure drop which contributes to the greater margin for system pressure drop increases. Furthermore, as a result of a reduction in the hydraulic loss coefficient, the hourglassed configured broached holes 53 contribute to greater margins for water level problems such as water level instability and high water levels resulting from high pressure drops. The hourglass configuration reduces fluid turbulence in the area of contact between tube 55 and the protruding member 54 of support plate 52 thereby reducing local deposition of magnetite and other particles on the support plate 52. The hourglass configuration also allows for greater rotational motions between tubes 55 and the protruding members 54 before experiencing binding due to a moment couple from opposing forces at the top and bottom edges of the tube support plate 52. According to the present invention, the tube support plate 52 is made of stainless SA-240 410S material with a specified high yield of 50 ksi or above and ultimate tensile strength (UTS) of 80 ksi or above. The following chart shows the superiority of the SA-240 410S stainless steel material of the present invention when compared to the SA-212 Gr.B carbon steel used to make the prior art tube support plates 47. From the foregoing it is thus seen that the tube support plates 52 made with SA-240 410S stainless material provide (1) improved corrosion resitance; (2) higher strength; and (3) improved compatibility to minimize fretting wear with the tubes 55 which are made of Alloy 690 material. While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles. |
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description | This application is based on French Patent Application No. 0451965 filed Mar. 9, 2004, the disclosure of which is hereby incorporated by reference thereto in its entirety, and the priority of which is hereby claimed under 35 U.S.C. §119. 1. Field of the Invention The invention relates to managed communication networks and more particularly to diagnostic devices for determining the causes of problems occurring in such networks. 2. Description of the Prior Art The person skilled in the art knows that problems occurring in communication networks can have various causes, for example a power outage, a broken connection, a breakdown or malfunction of a network equipment or a component thereof, software, integrating a version of a network equipment or a component thereof, or software that is not fully compatible with the remainder of the network. Many diagnostic devices (also known as diagnostic tools) for determining the causes of problems have been proposed in the past. Some use techniques based on object-oriented and/or rules-based programming languages, possibly managed by a rules engine. Of such devices, there may be mentioned, for example, Expert (Event Correlation expert) for constructing alarm correlation trees from rules defined manually, devices from ILOG that use a programmable rules engine for diagnosis, devices from Hewlett Packard, in particular the Network Node Manager®, version 6.4, and the Network Node Manager Extended Topology®, version 2.0, which use a technique based on fault models, the Fault Detective for Data Communications (FDDC) from Agilent, which replaces the fault diagnosis operations effected by technicians with automated diagnostic methods, and the TACO device from CISCO, which is a problem detection assistant. The main drawback of the above devices is their mode of acquiring information (also referred to as expert knowledge). If the diagnostic device is developed for a company that is not a systems integrator, the knowledge base or expert knowledge base is not well adapted to certain specific equipments or to certain combinations of equipments. If the diagnostic device is developed by a systems integrator, the knowledge base or expert knowledge base contains only basic information, with the result that certain features specific to the equipment are not taken into account, for example the type, method of fabrication, date of fabrication, version and mode of use. Critical information and the diagnostic devices themselves are generally not communicated to the user client. Defining new and specific diagnostic or verification technique therefore proves to be very difficult, and sometimes it is even the case that the tool cannot be modified at all. In other words, the above diagnostic devices suffer from a lack of flexibility. ALCATEL also offers a diagnostic device based on Bayesian probabilistic theory and used to define rules for refining hypotheses on the basis of concepts of additional evidence and background information, which lead to numbers each representing the probability that a hypothesis is true and used to construct Bayesian networks (also known as Bayesian diagrams) defining test operations associated with statistical or probabilistic weights. The main drawback of the above device is that its Bayesian networks, and the tests associated with them, cannot be modified once they have been integrated. Consequently, if a user client realizes that a Bayesian network is not totally adapted to his network, or that a specific equipment necessitates a particular test, the diagnostic device cannot be adapted. This kind of diagnostic device therefore also suffers from a lack of flexibility. No prior art diagnostic device proving entirely satisfactory, an object of the invention is therefore to improve on this situation. The invention therefore proposes a diagnostic device comprising diagnostic means comprising a knowledge base taking the form of basic diagnostic units, and processing means for establishing selected hierarchical associations between selected units from the knowledge base in order to constitute configurable diagnostic models adapted for determination by the diagnostic means of the causes of problems occurring within the network from information supplied by its network equipments. The diagnostic device may have the following additional features in particular, separately or in combination: the processing means may be adapted to associate basic diagnostic units by means of selected rules; in this case, the processing means may comprise a rules engine for establishing the selected hierarchical associations between the selected units, for example; also, at least some of the rules may be of the statistical type; its processing means may be adapted to associate at least some of said basic diagnostic units by means of selected models; its processing means may be adapted to associate certain selected basic diagnostic units in selected trees constituting certain of said diagnostic models; its processing means may be adapted to associate selected statistical or probabilistic weights with at least certain of said basic diagnostic units and/or at least certain of said rules and/or at least certain of said models; its processing means may be adapted to associate selected administrative costs with at least certain of said basic diagnostic units and/or at least certain of said rules and/or at least certain of said models; at least certain of said diagnostic models may take the form of a Bayesian network (or diagram); at least certain of said basic diagnostic units may take the form of a Bayesian network (or diagram); at least certain of said basic diagnostic units may take the form of sets of hierarchical tests; its processing means may be adapted to modify at least certain of said basic diagnostic units and/or at least certain of said rules and/or at least certain of said models and/or at least certain of said statistical or probabilistic weights and/or at least certain of said administrative costs; its processing means may comprise a man/machine interface adapted to enable a user to effect said associations and/or said modifications. Other features and advantages of the invention will become apparent on reading the following detailed description and examining the appended drawings. The appended drawings constitute part of the description of the invention as well as, if necessary, contributing to the definition of the invention. An object of the invention is to use one or more diagnostic models to determine the cause of a problem that has occurred within a managed communication network. The invention relates to any type of managed network (and in particular Internet protocol (IP) networks) and any type of service within a managed network. The diagnosis may relate to the network level (network equipments and configuration) or the management and service level (network equipments, configuration, quality of service (QoS), and service level agreement (SLA)). The invention proposes a diagnostic device DD comprising, as shown in FIG. 1, a diagnostic model MD for determining causes of problems from information supplied by the equipments of the network. A device DD of this kind is installed in the network management system (NMS), for example, or in the service management system of the network when it is a service that is to be diagnosed. For example, the information coming from the network equipments consists of alarms, which the network equipments send automatically to the NMS if they detect a problem (failure or malfunction) within themselves (i.e. affecting one of their components, for example an input or output interface) or with one of their connections. However, it may equally consist of management and/or operating information obtained from certain network equipments at the request of the NMS and generally stored in their management information base (MIB). It may equally consist of measured values of network parameters, for example the bandwidth used on certain connections or certain calls (traffic analysis) or the rate of loss of packets on certain connections or certain calls, which in particular enable network operators to monitor and manage the quality of service (QoS) associated with each user client (or each service) and defined by a service level agreement (SLA). Generally speaking, any information useful for the diagnosis may be fed to the diagnostic module MD of the diagnostic device DD. According to the invention, the diagnostic module MD includes an expert knowledge base BC taking the form of basic diagnostic units and a processing module MT for establishing selected hierarchical associations between selected units from the knowledge base BC in order to construct configurable diagnostic models adapted to determine the causes of problems. The knowledge base BC is preferably constructed from data (or information) from different sources, for example equipment design data (specification, configuration, validation etc., and problems and/or weaknesses already encountered), equipment fabrication data (components used, technologies used, etc., and problems and/or weaknesses already encountered), data from equipment tests carried out in the laboratory (critical failures, reliability, bugs, compatibility, service life, etc.), and information on use under real life conditions (such information coming in particular from user clients, maintenance services and failure reports and consisting, for example, of statistical information relating to reliability and to the timescale of equipment and component failures, the most frequent failures of equipments as a function of a specific use or a specific fabrication process, equipment compatibilities, service life, etc.). As shown in FIG. 1, the diagnostic device DD includes an analysis module MA for collecting data and information from the network itself or from the network operator and analyzing that data and information with a view to selecting data and information useful for a selected diagnosis. For example, the analysis module MA is divided into three analysis submodules SMA1 to SMA3 coupled to respective databases BD1 to BD3. For example, the analysis submodule SMA1 is dedicated to analyzing equipment design and fabrication data and information, the analysis submodule SMA2 is dedicated to analyzing equipment laboratory test data and information, and the analysis submodule SMA3 is dedicated to analyzing data and information on use under real life conditions. The expert knowledge data retained during the analysis effected by a submodule SMAi (in the present example i=1 to 3) is stored in the associated database BDi. The data and information on use under real life conditions generally vary in time, and it is advantageous to update them regularly, for example periodically, in the database BD3. Data may be analyzed in the various analysis submodules SMAi by any means, and in particular by means of statistical methods such as data mining, for example, or a learning technique, a signal processing technique, a prediction/trend technique or a technique based on experience. It is preferably carried out under the control of an expert. When the diagnostic device DD includes an analysis module MA, it also includes, as shown in FIG. 1, a knowledge base generation module MGB which is coupled to the analysis module MA (to be more precise to its databases BDi) and to the diagnostic module MD. The knowledge base generation module MGB may generate the knowledge base or bases BD necessary for the diagnostic module MD by the method indicated hereinafter, for example. For example, the knowledge base generation module MGB begins by constructing a knowledge core in the form of basic diagnostic units from equipment design and fabrication data and information stored in the database BD1. It then uses the laboratory equipment test data and information stored in the database BD2 to enhance the knowledge base. Finally, it adds to the enhanced knowledge core data and information concerning use under real life conditions stored in the database BD3, to construct a knowledge base BC in the form of basic diagnostic units adapted to the network to be diagnosed. Any technique known to the person skilled in the art may be used by the knowledge base generation module MGB to generate a knowledge base BC in the form of basic diagnostic units. Of such techniques, there may in particular be cited statistical techniques, techniques based on rules and/or models, and learning techniques, for example of the neural network or Petri network type. Generation of each knowledge base BC by means of the knowledge base generation module MGB is preferably carried out under the control of an expert. Once generated by the knowledge base generation module MGB, the knowledge base BC is communicated to the diagnostic module MD. Because it is generally the case that some of the data stored in the databases BDi varies in time (in particular the data stored in the database BD3), it is advantageous to update the knowledge base BC that is communicated to the diagnostic module MD regularly, for example periodically. The knowledge base generation module MGB may be adapted accordingly. It is important to note that the diagnostic device DD need not include the analysis module MA and the knowledge base generation module MGB if the knowledge base BC is supplied to it from elsewhere. The diagnostic module MD includes a processing module MT for establishing selected hierarchical associations between selected blocks of the knowledge base BC to construct configurable diagnostic models adapted to determine the causes of problems occurring within the network concerned. In the present context, the expression “hierarchical association” means any causal association or combination of blocks, i.e. an association or combination in which the blocks must be used relative to each other in a particular order, which may be predetermined. Any method may be used by the processing module MT to associate hierarchically basic diagnostic units. It may in particular use selected rules and/or selected models and/or statistical methods. One particularly simple example of a hierarchical association of three blocks that can be effected by the processing module MT and is not limiting on the invention is described below: execute block 1 of the knowledge base BC, if block 1 does not detect a fault then execute block 2, if block 2 does not defect a fault then execute block 3. It is important to note that at least some of the rules may be of the statistical type. FIG. 2 shows a more complex example of a hierarchical association, this time comprising thirteen blocks, which can be effected by the processing module MT and is not limiting on the invention. In this example, the processing module MT has established a diagnostic model adapted to determine the cause of packet loss in an Internet Protocol virtual private network (IP VPN). In this example the diagnostic model takes the form of a Bayesian network (or causal diagram) familiar to the person skilled in the art. Each node of the Bayesian network is designated by a name that represents the output variable of a set of basic tests to be executed comprising at least one such test. It should be remembered that a Bayesian network is intended, when it is executed, to detect any problem that may exist and its cause or causes. A Bayesian network is a causality tree. In the FIG. 2 example, three causes of packet loss are shown, each of which is assigned a certain probability: DropOnInputQueue (with probability X), RouterMisconfiguration (with probability Y), and DropOnOutputQueue (with probability Z), the sum of these three probabilities X, Y and Z being equal to 1. Similarly, within each branch leading away from PacketLoss, each sub-branch is assigned a probability. For example, one of the causes of the branch DropOnInputQueue is Throttle, which is assigned probability X1. The Bayesian nodes of the FIG. 2 example are defined below. LossPacket designates a scenario for finding the root cause of packet loss in an IP VPN. It executes various tests according to the cause probabilities. For example, the LossPacket scenario first tests interfaceInStatus (which is generally the most probable cause). Then, if interfaceInStatus is OK, it tests interfaceOutStatus (which is generally the second most probable cause). If interfaceOutStatus is NOK (not OK), LossPacket sends InterfaceOutStatus NOK, the cause of the problem (for example: an interface is not working) and the number of packets lost, if that can be determined. DropOnInputqueue is a variable indicating if packets have been dropped at an ingress interface. RouterMisconfiguration is a variable that cannot be observed directly. It indicates if a router is configured correctly. DropOnOutputQueue is a variable indicating if packets have been dropped at an egress interface. As previously indicated, within the Bayesian network dedicated to packet loss, DropOnInputQueue is assigned a probability X that represents the probability that the cause of the packet loss is linked to the input queue (InputQueue), while RouterMisconfiguration is assigned a probability Y that represents the probability that the cause of the packet loss is linked to misconfiguration of a router, and DropOnOutputQueue is assigned a probability Z that represents the probability that the cause of packet loss is linked to the output queue (OutputQueue). Similarly, within the branch associated with DropOnInputQueue, there is a probability X1 that the cause of packet loss is linked to HighCPUUtilization, a probability X2 that the cause of the packet loss is linked to Throttle, and a probability X3 that the cause of packet loss is linked to InterfaceInStatus. Consequently, if it is wished to determine whether the cause of packet loss is linked to the input queue (InputQueue), it is necessary to determine whether HighCPUUtilization is OK or NOK (not OK) and/or if Throttle is OK or NOK and/or if InterfaceInStatus is OK or NOK. InterfaceInStatus is a variable modeling the status of the input interfaces. Throttle is a variable indicating whether a port is out of service or not and provides an indication as to the state of (over)loading of a router. It indicates the number of times that the receiver at a given port has been out of service, for example because of a processing overload or a buffer overload. HighCPUUtilization is a variable indicating whether the processing (or CPU) capacity of a router is overloaded or not. BGP4MIB is a variable representing the configuration status of a border gateway protocol (BGP). For example, if BGP4MIB is OK, the BGP is configured correctly, whereas if BGP4MIB is NOK, the BGP is not configured correctly. IPForwardMIB is a test variable for determining whether an LSP has been set up or not. ClassBasedQoSMIB is a test variable for determining if the quality of service (QoS) policy is appropriately configured and implemented in the router. InterfaceOutStatus is a variable modeling the status of the output interfaces. BadConfOfWRED is a test that verifies the configuration of the weighted random early detection (WRED) algorithm that verifies for each output interface associated with an output label (label out) if a random early detection (RED) type queuing strategy has been defined, after which it collects the total number of packets extracted. QueueMIB is a variable for verifying if the policy models (policy-map) are defined in an input interface and an output interface. In this example of a Bayesian network, the respective positions of the nodes are representative of the probabilities that are associated with the respective branches to which they belong. Additional information on Bayesian networks and their use in diagnostic devices can be found in the document by F. Jensen, “An introduction to Bayesian Networks”, UCL Press, 1996 (out of print, reissued in 2001). It is important to note that at least some of the basic diagnostic units that are used in a diagnostic model (whether of the Bayesian network type or not) can also take the form of a Bayesian network (or diagram). It is equally important to note that a diagnosis can be arrived at through means other than tests, and in particular active or passive measurements, alarm correlation, configuration verification, and verification of the consistency of the configuration of a service across the network and of the reading of parameters specific to an equipment stored in management information bases (MIBs) or available in certain network equipments such as routers. A detailed example of obtaining information for generating diagnostic tests relating to quality of service (QoS) within an IP VPN is described in the document by Gérard Delègue et al., “IP VPN Network Diagnosis: Technologies and Perspectives”, 3rd International Conference on Networking, March 2002. The processing module MT may comprise a rules engine MR for establishing selected hierarchical associations between selected basic units, preferably under the control of an expert. In the case of Bayesian network type diagnostic models constructed by associating basic test units by means of rules and in the case of diagnostic models constructed by associating basic test units by means of models, the processing module MT can be adapted to associate selected statistical or probabilistic weights and/or selected administrative costs with at least some of the basic diagnostic units and/or at least some of the rules and/or at least some of the models. Associating statistical or probabilistic weights means that certain sets of tests can be made more (or less) important than other sets of tests in the context of a diagnosis. Associating administrative costs means that certain sets of tests can be used only if the cost of a diagnosis is important. Associating selected statistical or probabilistic weights and/or selected administrative costs is preferably effected under the control of an expert. In this variant, it is advantageous to use a man/machine interface IHM of the type described above to display on a screen a blank tree selected by an expert and to have that expert fill in the nodes of that tree (or a portion thereof) with basic diagnostic units. The processing module MT can be adapted to establish the associations automatically, on the basis of instructions supplied by an expert. However, it can equally be adapted to propose or to make available some or all of the basic units of a knowledge base BC and/or some or all of the rules linking said basic units that might be envisaged, in order for an expert to define the associations intended to constitute a diagnostic model. In this case, the diagnostic module MT is also responsible for the (physical) generation of the diagnostic models defined by the user. To enable an expert to control (or define) each association, whether it is an association of blocks in the context of generating a diagnostic model or an association of statistical or probabilistic weights and/or administrative costs, the processing module MT comprises a man/machine interface IHM, for example a graphical user interface (GUI). In the absence of an interface IHM, the expert can send his instructions to the processing module MT by means of any type of command, for example of the command line (CLI) type, or code. This kind of interface IHM may also be used by an expert to modify at least some of the basic diagnostic units and/or at least some of the rules (and where applicable their statistical or probabilistic weights) and/or at least some of the models and/or at least some of the statistical or probabilistic weights and/or at least some of the administrative costs. In the present context, the term “modify” means any intervention whose purpose is to add, delete or change something. Consequently, a modification may consist in adding or deleting or changing one or more basic units (or a portion thereof) and/or one or more rules and/or models in a knowledge base BC or in a diagnostic model. An embodiment is described above in which the processing module MT effects hierarchical associations by means of rules and/or models. However, a variant may be envisaged in which the processing module MT effects hierarchical associations of basic diagnostic units selected within selected trees. In this case, each completed tree finally constitutes a diagnostic model. In this variant, it is advantageous to use a man/machine interface IHM of the type described above to display on a screen a blank tree selected by an expert and to have the expert fill in nodes of that tree (or a portion thereof) with basic diagnostic units. In this case, association simply consists in stringing basic units to be executed in the order defined by the tree concerned, without rules or models linking associated basic units. Once a diagnostic model has been generated by the processing module MT and activated, it can then be used by a calculation module MC of the diagnostic module MD. The calculation module MC feeds the activated diagnostic model with information that comes (directly or indirectly) from network equipments, for example alarms, and delivers to an output a diagnosis, i.e. the cause or causes of a problem that has occurred within the network. The calculation module MC is adapted as a function of the diagnostic model or models that it uses. It is therefore designed to run the scenario of a diagnostic model and uses, for example, a database, SNMP tools etc., and delivers at an output results constituting diagnostics. For example, the calculation module MC may be coupled to an auxiliary module for proposing to the network operator actions for remedying each cause determined in a diagnosis. It is important to note that the diagnostic device DD can include one or more auxiliary diagnostic modules or one or more auxiliary diagnostic models in addition to that (MD) described above and of different designs. In this case, the calculation module MC of the diagnostic module MD can be adapted to use each activated diagnostic model, regardless of its design. It is also important to note that a diagnosis effected by a diagnostic device DD can relate to network equipments of any type, whether pure hardware (components), pure software or combinations thereof. The diagnostic device DD of the invention, and in particular its analysis module MA, its knowledge base generation module MGB and its diagnostic module MD, may be implemented in the form of electronic circuits, software (data processing) modules or a combination of circuits and software. The invention is not limited to the embodiments of a diagnostic device described above by way of example only, and encompasses all variants that the person skilled in the art might envisage that fall within the scope of the following claims. |
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abstract | A semiconductor manufacturing factory includes a plurality of semiconductor manufacturing apparatuses including an exposure apparatus for exposing a substrate by using a plurality of charged particle beams, a local area network for connecting the plurality of semiconductor manufacturing apparatuses, and a gateway for connecting the local area network to an external network of the semiconductor manufacturing factory. The exposure apparatus includes a lens array, which has a plurality of lenses and directs a plurality of charged particle beams onto a substrate. The lens array includes at least two electrodes having a plurality of apertures on the paths of the plurality of charged-particle beams, and a shield electrode interposed between the at least two electrodes. |
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062597566 | claims | 1. In a nuclear reactor having a core, said core including plural control blades and fuel assemblies with each control blade operationally associated with four fuel bundles of each fuel assembly, sets of said control blades forming discrete control blade groups forming a core pattern including first and second main groups thereof, respectively, symmetrically and asymmetrically arranged about the core, each main group having first and second sub-groups, said first sub-groups of said main group including first and second operational sub-groups, respectively, of control blades; each first sub-group of said first main group being flanked by first sub-groups of said second main group in a first direction and by the second sub-group of said second main group in a second direction normal to said first direction; each second sub-group of said first main group being flanked by second sub-groups of said second main group in said first direction and by first sub-groups of said second main group in the second direction; each first sub-group of said second main group being flanked by a first sub-group of said first main group in the first direction and by said second sub-group of said first main group in the second direction; each second sub-group of said second main group being flanked by a second sub-group of said first main group in the first direction and by the first sub-group of said first main group in the second direction; each blade of each first main group being movable between withdrawn, deep and shallow positions relative to said core and said fuel bundles associated with said first main group, each blade of each second main group being movable between withdrawn and shallow positions relative to said core and to fuel bundles associated with said second main group; a method of operating the nuclear reactor comprising the steps of: inserting into the core from a withdrawn position into a deep position a different sub-group of the blades of the first and second sub-groups and operational sub-groups of said first main group at the beginning of at least each of three successive time periods, respectively, with predetermined sub-groups of blades of said first and second main groups withdrawn from the core at the beginning of each said successive time period; inserting into the core from a withdrawn position into a shallow position a different sub-group of the blades of the first and second sub-groups of said first and second main groups at the beginning of each of said successive time periods with said predetermined sub-groups of blades of said first and second main groups withdrawn from the core at the beginning if each said successive time period; and maintaining selected sub-groups of said withdrawn blades at the beginning of each successive time period in a withdrawn position for at least two consecutive time periods. a method of operating the nuclear reactor comprising the steps of: inserting into the core from a withdrawn position into a deep position different selected blades of the first and second sub-groups of said first main group at the beginning of at least each of three successive time periods, respectively, with predetermined sub-groups of blades of said first and second main groups withdrawn from the core at the beginning of each said successive time period; inserting into the core from a withdrawn position into a shallow position different selected blades of the first and second sub-groups of said first and second main groups at the beginning of each of said successive time periods with said predetermined sub-groups of blades of said first and second main groups withdrawn from the core at the beginning if each said successive time period; and maintaining selected withdrawn blades at the beginning of each said successive time period in a withdrawn position for at least two consecutive time periods. 2. A method according to claim 1 wherein any one control blade of said plural control blades remains withdrawn for at least two consecutive time periods after having been withdrawn from an inserted position. 3. A method according to claim 1, including the further steps of inserting into the core from a withdrawn position into a deep position said first sub-groups of control blades of said first main group at the beginning of a predetermined time period, withdrawing said first sub-groups of control blades of said first main group at the end of said predetermined time period, and maintaining said first sub-groups of said control blades of said first main group withdrawn from said core for at least two consecutive time periods immediately subsequent to said predetermined time period. 4. A method according to claim 3 including the further steps of inserting into said core from a withdrawn position into a shallow position the first operational sub-groups of said first sub-group of said first main group at the beginning of said predetermined time period, withdrawing said first operational sub-groups of said first sub-group of said first main group at the end of said predetermined time period and maintaining said first operational sub-groups of said first sub-group of said first main group withdrawn from said core for at least two consecutive time periods immediately subsequent to said predetermined time period. 5. A method according to claim 4 wherein any one control blade of said plural control blades remains withdrawn for at least two consecutive time periods after having been withdrawn from an inserted position. 6. A method according to claim 1, including the further steps of inserting into the core from a withdrawn position into a shallow position the second sub-group of said second main group of control blades at the beginning of a predetermined time period and maintaining said second sub-groups of said second main group of control blades withdrawn from said core for at least two consecutive time periods, immediately subsequent to said predetermined time period. 7. A method according to claim 1, including the further steps of inserting into the core from a withdrawn position into a deep position the operational sub-groups of said second sub-group of said first main group of control blades at the beginning of a predetermined time period, withdrawing said second operational sub-groups of said second sub-group of said first main group at the end of said predetermined time period and maintaining said second operational sub-groups of said first main group of said control blades withdrawn from said core for at least two consecutive time periods immediately following said predetermined time period. 8. A method according to claim 1, including the further steps of inserting into the core from a withdrawn position into a deep position said second sub-groups of said first main group of control blades at the beginning of a predetermined time period, withdrawing said second sub-groups of said first main group at the end of said predetermined time period and maintaining said second sub-groups of said first main group withdrawn from said core for at least two consecutive time periods immediately subsequent to said predetermined time period. 9. A method according to claim 8 including the further steps of inserting into said core from a withdrawn position into a shallow position the second sub-groups of said second main group of control blades at the beginning of said predetermined time period, withdrawing said second sub-groups of said second main group at the end of said predetermined time period and maintaining said second sub-groups of said second main group withdrawn from said core for at least two consecutive time periods immediately subsequent to said predetermined time period. 10. In a nuclear reactor having a core, said core including plural control blades and fuel assemblies with each control blade operationally associated with four fuel bundles of each fuel assembly, sets of said control blades forming discrete control blade groups forming a core pattern including first and second main groups thereof, respectively, symmetrically and asymmetrically arranged about the core, each main group having first and second sub-groups, each sub-group at each control blade location within the core being located alternately in both orthogonally-related X and Y directions in plan view of the core, said first sub-group of said first main group including an operational sub-group; 11. A method according to claim 10 wherein any one control blade of said plural control blades remains withdrawn for at least two consecutive time periods after having been withdrawn from an inserted position. 12. A method according to claim 10, including the further steps of inserting into the core from a withdrawn position into a deep position said first sub-groups of control blades of said first main group at the beginning of a predetermined time period, withdrawing said first sub-groups of control blades of said first main group at the end of said predetermined time period, and maintaining said first sub-groups of said control blades of said first main group withdrawn from said core for at least two consecutive time periods immediately subsequent to said predetermined time period. 13. A method according to claim 12 including the further steps of inserting into said core from a withdrawn position into a shallow position the first operational sub-groups of said first sub-group of said first main group at the beginning of said predetermined time period, withdrawing said first operational sub-groups of said first sub-group of said first main group at the end of said predetermined time period and maintaining said first operational sub-groups of said first sub-group of said first main group withdrawn from said core for at least two consecutive time periods immediately subsequent to said predetermined time period. 14. A method according to claim 13 wherein any one control blade of said plural control blades remains withdrawn for at least two consecutive time periods after having been withdrawn from an inserted position. 15. A method according to claim 10, including the further steps of inserting into the core from a withdrawn position into a shallow position the second sub-group of said second main group of control blades at the beginning of a predetermined time period and maintaining said second sub-groups of said second main group of control blades withdrawn from said core for at least two consecutive time periods, immediately subsequent to said predetermined time period. 16. A method according to claim 10, including the further steps of inserting into the core from a withdrawn position into a deep position the operational sub-groups of said second sub-group of said first main group of control blades at the beginning of a predetermined time period, withdrawing said second operational sub-groups of said second sub-group of said first main group at the end of said predetermined time period and maintaining said second operational sub-groups of said first main group of said control blades withdrawn from said core for at least two consecutive time periods immediately following said predetermined time period. 17. A method according to claim 10, including the further steps of inserting into the core from a withdrawn position into a deep position said second sub-groups of said first main group of control blades at the beginning of a predetermined time period, withdrawing said second sub-groups of said first main group at the end of said predetermined time period and maintaining said second sub-groups of said first main group withdrawn from said core for at least two consecutive time periods immediately subsequent to said predetermined time period. 18. A method according to claim 17 including the further steps of inserting into said core from a withdrawn position into a shallow position the second sub-groups of said second main group of control blades at the beginning of said predetermined time period, withdrawing said second sub-groups of said second main group at the end of said predetermined time period and maintaining said second sub-groups of said second main group withdrawn from said core for at least two consecutive time periods immediately subsequent to said predetermined time period. |
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description | The invention described herein was made by employees of the United States Government and may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefore. The present invention relates generally to the field of rocket propulsion, and more specifically to a device utilizing a pulsed, variable, high precision laser ignition/ablation thruster for propulsion. Aerospace propulsion systems are known in the art. Rockets are propelled using either liquid or solid fuel chemical propulsion or some combination of both. Each system has unique advantages and disadvantages. Liquid fuel chemical propulsion systems can be throttled and are capable of being turned on and off. In addition, the thrust levels can be varied resulting in greater efficiency and flexibility during operation. Liquid propulsion systems, however, generally have a higher mass and require more complex and costly components than do solid rocket systems. Solid rocket propulsion systems have a lower level of controllability than liquid rocket propulsion systems. Unlike liquid rocket propulsion systems, solid rocket propulsion systems cannot be turned off once lit. Once the propulsion system is turned on, it will continue to burn until all fuel is used up. The inability to be turned off limits the operational envelope and presents a potential safety hazard. Solid rocket propulsion systems respond more quickly than liquid fuel propulsion systems once turned on. In addition, solid rocket propulsion systems generally have higher performance than liquid fuel propulsion systems, providing a greater thrust/specific impulse per fuel weight. The weight and performance of the fuel is a significant factor for aerospace craft as it is estimated that each additional pound adds $10,000 to the cost of putting a payload into space. Propulsion systems are usually tailored to meet certain mission requirements and specifications and may have to start and stop a limited number of times. As space applications continue to diversify, scalability in propulsion systems is important and allows rocket builders to more effectively tailor their designs to a given application. Depending on the mission, liquid propulsion systems also may have inconvenient storage requirements or limited shelf life and may be inconvenient for modular packaging. For example, liquid systems may require the continued cooling for cryogenic fuels with associated insulation and storage tanks while solids would only need a “room temperature” environment. It is very desirable to have a propulsion system that captures the controllability of liquid propulsion and the high performance of solid propulsion. It is very desirable to have a propulsion system that is scalable and able to be tailored to a variety of applications, which allows for variable thrust or specific impulse levels. It is very desirable to have a propulsion system that can be started, stopped and restarted as needed, and which aids in providing high precision performance. It is very desirable to have a propulsion system with modular design for convenient resupplying, refueling and modifying of ignition/ablation material. It is further desirable to have a propulsion system that allows multiple systems to be integrated into a single craft. The present invention is a pulsed, variable, high precision laser ignition/ablation thruster, which captures the advantages from both liquid and solid propulsion. A reinforced, transparent tape in back carries a volume of propellant or ablation material into the ignition/ablation chamber. A sufficiently intense laser pulse passes through a transparent, high temperature, high pressure laser window and through the transparent carrier tape, striking the back surface of the target propellant/ablation material. If a propellant is used, it is ignited and the expanding gas passing through a rocket nozzle generates thrust. If an ablative material such as paraffin is used, the substance is converted to an expanding gas that passes through a rocket nozzle producing thrust. Once this event is complete, the tape then moves a new target element into the ignition/ablation chamber and the event is repeated. Many events may take place per second creating high average thrust and specific impulse. Tape speed for a given propellant or ablative substance determines thrust level. This process can be employed on size scales ranging from very small to very large, and may be synchronized with a computer control. As used herein, the term “containment border structure” refers to a component of a transport structure that encloses ignition or ablation material. As used herein, the term “flammable” means subject to burning when exposed to heat. As used herein, the term “highly resilient material” refers to a material that is tolerant of high temperatures, pressure, and tension, is able to withstand vacuum environments and environments with an extreme range of temperatures, and which is resistant to tangling. Examples of highly resilient material include, but are not limited to para-aramid synthetic fiber (e.g., Kevlar®) and polyimide (e.g., Kapton®). As used herein, the term “nonconductive” means not capable of conducting an electrical current. As used herein, the term “opaque” means a material that absorbs a laser beam rather than allowing it to pass through. As used herein, the term “propellant material” refers to a substance capable of being ignited or ablated. As used herein, the term “reel” refers to a rotating component used for storing, dispensing, and/or protecting a transport structure. As used herein, the term “reinforcing members” refers to material added to a layer of propellant tape to add strength. Reinforcing members may include, but are not limited to wire mesh, metallic wires, wire ribbon, wire threads, Kevlar® threads, and nylon threads. As used herein, the term “synthetic fiber” refers to a material that is stronger than steel and which is tolerant to high pressure and temperature. Examples of synthetic fibers include, but are not limited to para-aramid fibers (e.g., Kevlar® and Twaron®), polymer fibers, polyethylene fibers, nylon fibers, carbon fibers, and glass fibers. As used herein, the term “transport structure” or “propellant tape” refers to a component that moves propellant material through an ignition/ablation chamber. For the purpose of promoting an understanding of the present invention, references are made in the text to exemplary embodiments of a laser ignition/ablation propulsion system, only some of which are described herein. It should be understood that no limitations on the scope of the invention are intended by describing these exemplary embodiments. One of ordinary skill in the art will readily appreciate that alternate but functionally equivalent materials, components, and placement may be used. The inclusion of additional elements may be deemed readily apparent and obvious to one of ordinary skill in the art. Specific elements disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one of ordinary skill in the art to employ the present invention. It should be understood that the drawings are not necessarily to scale; instead, emphasis has been placed upon illustrating the principles of the invention. In addition, in the embodiments depicted herein, like reference numerals in the various drawings refer to identical or near identical structural elements. Moreover, the terms “substantially” or “approximately” as used herein may be applied to modify any quantitative representation that could permissibly vary without resulting in a change to the basic function to which it is related. FIG. 1 illustrates an exemplary embodiment of laser ignition/ablation propulsion system 100 comprised of laser 10, laser window 35, target containment walls 42a, 42b, ignition chamber 40, storage feed reel 20, storage takeup reel 22, and propellant tape 25. Laser 10 is positioned so that laser pulse 12 passes through laser window 35 between target containment walls 42a, 42b. Propellant tape 25 contains propellant targets 30 (See FIG. 2a), comprised of ignition/ablation material, at regular intervals. Propellant tape 25 is wound on storage feed reel 20, which unwinds, feeding propellant tape 25 under laser 10. Propellant tape 25 is rewound on storage takeup reel 22 after propellant targets 30 have been ignited/ablated. When a propellant target 30 is positioned between target containment walls 42a, 42b, propellant tape 25 pauses and laser 10 fires sending laser pulse 12 through laser window 35. Laser pulse 12 strikes the surface of propellant target 30 igniting or ablating it, resulting in a thrust impulse. Propellant tape 25 then carries another propellant target 30 over ignition chamber 40. The movement of propellant tape 25 is synchronized to the firing of laser 10 so that a new propellant target is in position each time laser 10 fires. The resulting thrust/specific impulse may be precisely controlled by varying the speed of propellant tape 25 and the firing of laser 10. In addition, the frequency of laser pulse 12 will be a direct function of the burn rate of propellant target 30. The burn of propellant target 30 must be complete prior to moving a new propellant target into ignition chamber 40. The ignition transient time, steady-state burn-time, and tail-off transient for each propellant target 30 needs to be considered. Heat transfer must also be considered. In the embodiment shown, laser window 35 is integrated with ignition chamber 40, which is comprised of a material that is tolerant of high temperatures and high pressure, and is transparent to the wavelength of laser pulse 12. Laser window 35 prevents the hot gas which results from ignition/ablation from escaping through the top of ignition chamber 40 helping to control the outflow of gas by forcing it to pass through nozzle 85. Laser window 35 may be comprised of a material including, but not limited to polycarbonate resin thermoplastic (e.g., Lexan®), glass, plastic, resin, quartz, silicon, or any other material(s) that is transparent to a laser beam and is tolerant to high temperatures and pressure. FIG. 2a illustrates a top view of a first exemplary embodiment of propellant tape 25 for laser ignition/ablation propulsion system 100. Propellant tape 25 is comprised of a plurality of discrete propellant targets 30 positioned at regular intervals between transparent back cover 26 and transport layer 27. Propellant tape 25 is positioned so that transparent back cover 26 faces upward toward laser pulse 12 (see FIG. 2b). The design of propellant tape 25 is crucial. Propellant tape 25 must protect propellant targets 30 during storage and when a propellant target is ignited/ablated. Propellant tape 25 must prevent the contingency of other propellant targets igniting/ablating in an uncontrolled chain reaction. In the embodiment shown, transparent back cover 26 is a transparent, heavy duty, relatively thick foundation tape layer that is transparent to the wavelength of laser pulse 12 (not shown). Transparent back cover 26 must be comprised of a material that is robust and thick enough to tolerate the transient temperature and pressure that occurs during ignition/ablation. Openings are cut in transport layer 27 to the desired size of ignition/ablation material. The openings are then covered with a nonflammable membrane 31, which is secured to transport layer 27. The membrane 31 may be bonded, glued, or sewn to the front of transport layer 27. Containment border structures 29 are mounted to transport layer 27 so that they surround the openings. Ignition/ablation material is then attached to transport layer 27 forming propellant targets 30. In various embodiments, propellant targets 30 may be comprised of ignition or ablation material. Examples of ignition material include, but are limited to shuttle solid rocket booster propellant, Ammonium Perchlorate Composite Propellant, or another solid rocket propellant known in the art. For lower thrust levels, ablation material, such as paraffin may be used. Propellant targets 30 may be attached to transparent back cover 26 via adhesive properties of the ignition/ablation material or may be glued to transparent back cover 26 using adhesive. Transport layer 27 is secured to transparent back cover 26 so that propellant targets 30 are secured between transparent back cover 26 and transport layer 27. Transport layer 27 and transparent back cover 26 may be secured together by bonding, gluing, sewing, or another attachment means known in the art to form propellant tape 25. Transport layer 27 faces toward ignition chamber 40 (not shown). When propellant target 30 is ignited/ablated, propellant target 30 bursts through the membrane 31 into ignition chamber 40. In the embodiment shown, transparent back cover 26, transport layer 27, and the membrane 31 may be comprised of conductive materials, nonconductive materials, or a combination thereof. For example, transparent back cover 26 and transport layer 27 may be comprised entirely of nonconductive materials including, but not limited to para-aramid synthetic fiber (e.g., Kevlar®) and polyimide (e.g., Kapton®). The use of nonconductive materials prevents an electrical current from traveling through propellant tape 25 causing propellant targets other than the one in the ignition chamber to ignite. In various other embodiments, transparent back cover 26 and/or transport layer 27 may further contain reinforcing members which are nonconductive (e.g., para-aramid synthetic fibers, nylon threads) or nonconductive (e.g., metallic threads). The use of only nonconductive materials may be desirable to maximize safety and reliability; however, metallic reinforcement may be required for maximum performance. Similarly, the membrane 31 may be comprised of a relatively thin nonconductive material including, but not limited to plastic film, polyimide film, or other plastic film, and/or a conductive material including, but not limited to aluminum foil or another type of metallic foil. The membrane 31 enhances the storage life of propellant targets 30. In various embodiments, the membrane 31 is comprised of aluminum foil or another type of foil, and/or may be comprised of multiple layers (e.g., a conductive layer and a nonconductive layer). In various embodiments, an additive may be added inside the membrane 31 to further increase the storage capability of propellant targets 30. Transport layer 27 is the primary drive tape and must be thick enough to allow propellant tape 25 to be driven at a high rate of speed. In addition, transport layer 27 must be impervious to being burned cutting propellant tape 25 in multiple pieces, which would affect the movement of propellant tape 25. Transparent back cover 26 and transport layer 27 hold propellant targets 30 firmly in position during movement of propellant tape 25 and further enables propellant targets 30 to be accurately aligned between laser widow 35 (not shown) and ignition chamber 40. In the embodiment shown, propellant tape further includes sprocket holes 28, which correspond to inner gear sprockets 66 of takeup reel 20 (not shown) and aid in the unraveling of propellant tape 25. In the embodiment shown, propellant targets 30 are circular, but in other embodiments may be of another shape including, but not limited to doughnut-shaped, oval, square, rectangular, star-shaped, or may have an undefined shape or be randomly shaped. In other embodiments, propellant targets 30 have an array pattern so that one element of the array pattern is ignited and subsequently ignites other elements of the array. The cross section of propellant target 30 may also vary. For example, propellant target 30 may be concave or convex in order to optimize performance and cost. In various embodiments, propellant tape 25 may further include optional filler material 33 to smoothen propellant tape 25 so it is better adapted for winding/unwinding on storage feed reel 20 and storage takeup reel 22. In embodiments where ablation material, rather than ignition material, is used, the ablation material may be located continuously along the propellant tape. In various embodiments, one or more additional layers of transparent layers with square or circular openings may be joined continuously to the transparent back cover 26 for additional positioning and support of propellant tape 25. In still other embodiments, inserts are attached to transparent back cover 26 and are used to surround propellant targets 30. These inserts may be opaque to the wavelength of laser pulse 12. In various embodiments, transparent back cover 25 and transport layer 27 materials may vary depending on the ignition/ablation material used for propellant targets 30 and the associated ignition/ablation temperatures and pressures. The spacing and size of propellant targets 30 on propellant tape 25 is dependent upon a number of factors including, but not limited to the ignition/ablation material being used, the amount of ignition/ablation material in each propellant target, the length of propellant tape 25, the speed that propellant tape 25 moves through the ignition chamber, operation time, and the application for which laser ignition/ablation propulsion system 100 is being used. Propellant targets 30 should be located far enough apart so that one propellant target can be ignited without the risk of igniting adjacent propellant targets. If the propellant targets are located too close together, igniting/ablating one propellant target may cause a second propellant target to ignite/ablate outside of the ignition chamber. In an exemplary embodiment, propellant targets are uniformly spaced. In embodiments where the desired thrust variations for a mission application are known in advance, non-uniformed spacing of propellant targets may be desired. FIG. 2b illustrates a side view of a first exemplary embodiment of propellant tape 25 showing the direction that laser pulse 12 passes through propellant tape 25. FIG. 2c illustrates a top view of a second exemplary embodiment of propellant tape 25. In the embodiment shown, propellant tape 25 further includes wires 50 between propellant targets 30 and sprocket holes 28. Wires 50 provide additional reinforcement for extremely energetic events and only minimally affect the flexibility of propellant tape 25. FIG. 2d illustrates a top view of a third exemplary embodiment of propellant tape 25. In the embodiment shown, propellant tape 25 further includes wire ribbon 52 for additional reinforcement. In various embodiments, propellant tape 25 may be reinforced by embedding steel, para-aramid synthetic fiber, or other high tensile strength wires or threads which run the length of propellant tape 25. A mesh matrix may also be used to reinforce propellant tape 25. The addition of metallic elements (e.g., threads, wires, wire ribbon) provides a strong border for propellant tape 25 decreasing the likelihood that propellant tape 25 will be cut by ignition/ablation. The width and thickness of propellant tape 25 may also be adjusted to decrease the likelihood of propellant tape 25 being cut. FIGS. 3a through 3d illustrate perspective views of exemplary shapes of propellant targets. FIG. 3a illustrates propellants that are convex, FIG. 3b illustrates propellant targets that are concave, FIG. 3c illustrates donut-shaped propellant targets and FIG. 3d illustrates propellant targets that are arranged in an array. Propellant targets may be shaped and arranged in order to optimize performance and cost for each application. FIG. 4a illustrates a back view of an exemplary embodiment of propellant tape storage feed reel 20. Propellant tape 25 is wound on storage feed reel 20 and fed into ignition chamber 40 (not shown) and then rewound on storage takeup reel 22 (FIGS. 3a and 3b). In the embodiment shown, storage feed reel 20 is driven by gearbox 60 and motor 62, which is controlled by controller 64 (e.g., a computer). Controller 64 is isolated outside of the contained area where ignition/ablation occurs. Controller 64 may be hard-wired or wireless and a single controller may be capable of controlling multiple laser ignition/ablation propulsion systems. In an exemplary embodiment, controller 64 controls all aspects of thruster operation and communicates with reel motors and laser 10 (not shown), as well as the spacecraft controller. One controller may operate several reels depending on the mission application. FIG. 4b illustrates a front view of an exemplary embodiment of propellant tape storage feed reel 20 showing propellant tape 25, the direction of unraveling, and inner gear sprockets 66. Inner gear sprockets 66 correspond to sprocket holes 28 (not shown) in propellant tape 25 aiding in the placement and unraveling of propellant tape 25. FIG. 5a illustrates a back view of an exemplary embodiment of propellant tape storage takeup reel 22. In the embodiment shown, storage takeup reel 22 is driven by gearbox 60 and motor 62, which is controlled by controller 64. In the embodiment shown, controller 64 controls all aspects of thruster operation. In the embodiment shown, both storage feed reel 20 and storage takeup reel 22 are comprised of light, tough, heat-resistant materials. Storage feed reel 20 and storage takeup reel 22 may be comprised of nonconductive material including, but not limited to high strength plastic such as Kapton®, or carbon composite, and/or a conductive material including, but not limited to aluminum, beryllium, and combinations thereof. In addition, storage feed reel 20 protects propellant tape 25 from outside contamination and humidity. In various embodiments, one or both reels may be powered. For example, only storage takeup reel 22 is driven by an electric motor and the tension from storage takeup reel 22 is used to unwind propellant tape 25 from storage feed reel 20. In an exemplary embodiment, both storage feed reel 20 and storage takeup reel 22 have gearing which allows them to be driven by a single electric motor. Driving both reels allows for precise control of the tension of propellant tape 25. The controller would sense this level of tension and manage it accordingly to minimize the chance of pulling apart the tape. FIG. 5b illustrates a front view of an exemplary embodiment of propellant tape storage takeup reel 22 showing propellant tape 25 and inner gear sprockets 66 which correspond to sprocket holes 28 (not shown) on propellant tape 25. FIG. 6 illustrates a cross sectional of an exemplary embodiment of ignition chamber 40 showing laser window 35, target containment walls 42a, 42b, tape containment walls 74a, 74b, synchronizing mechanism 78a, 78b, propellant tape 25, propellant target 30, expended propellant target 32, and laser pulse 12. Target containment walls 42a, 42b and tape containment walls 74a, 74b isolate the ignition/ablation event from the rest of propellant tape 25, from other propellant targets 30, and from storage feed reel 20 and storage takeup reel 22. Target containment walls 42a, 42b seal off the ignition chamber 40 during an ignition/ablation event. During the ignition/ablation event, the only escape path for expanding gases is through nozzle 85 (not shown). Synchronizing mechanisms 78a, 78b are movable and are used to place additional pressure on propellant tape 25. Synchronizing mechanisms 78a, 78b are lowered creating an additional barrier between the ignited/ablated propellant target 30 and the adjacent propellant targets and reels 20, 22 (not shown) helping to maintain the structure of propellant tape 25 and to force the resulting hot gas into through nozzle 85 (not shown). Synchronizing mechanisms 78a, 78b are then retracted to allow propellant tape 25 to carry another propellant target 30 into ignition chamber 40. In the embodiment shown, synchronizing mechanisms 78a, 78b are lowered and retracted using a spring; however, in other embodiment another mechanism, such as movable pistons, may be used. In the embodiment shown, tape containment walls 74a, 74b are fixed and target containment walls 42a, 42b are movable and are synchronized to lift away from propellant tape 25 prior to propellant tape 25 moving, allowing a new propellant target 30 to be brought into ignition chamber 40. Propellant tape 25 also carries away all post-ignition/ablation contaminants preventing them from clouding laser window 35. FIG. 7 illustrates an exemplary embodiment of fiber optic transmission of laser pulse 12. In the embodiment shown, laser 10 is not located in the proximity of propellant target 30 and fiber optic cable 90 is used to transmit laser pulse 12 from laser 10 to propellant target 30. Fiber optic cable 90 is capable of carrying a sufficiently intense laser pulse to achieve ignition/ablation, enabling many packaging options for laser 10. Utilizing fiber optics enables the use of remote lasers from either the ground, space, internal to the ignition/ablation propulsion system 100, or from anywhere with a suitable environment to power the thruster. FIG. 8 illustrates a second exemplary embodiment of a packaging option for ignition/ablation propulsion system 100 showing controller 64, laser 10, ignition chamber 40, storage feed reel 20, storage takeup reel 22, and nozzle 85. The direction in which nozzle 85 points determines the direction of thrust. Nozzle 85 is controlled by controller 64. In the embodiment shown, ignition/ablation propulsion system 100 has one nozzle; however, in other embodiments, ignition/ablation propulsion system 100 may include more than one nozzle pointed in the same or in varying directions. The packaging option for ignition/ablation propulsion system 100 shown in FIG. 8 enables convenient packing into thruster modules with relatively long storage life. In addition, modular packaging allows for replenishment of attitude control propulsion subsystems (e.g., for a return mission). If scaled up, these modules could be used to push a potentially hazardous asteroid, meteoroid, or comet away avoiding a potential impact with Earth. FIG. 9a illustrates an exemplary embodiment of a configuration of a plurality of packaged ignition/ablation propulsion systems 100. In the embodiment shown, ignition/ablation propulsion systems 100 are stacked to achieve greater performance. FIG. 9b illustrates a second exemplary embodiment of a configuration of a plurality of packaged ignition/ablation propulsion systems 100 combined to thrust in several directions. In another embodiment, a movable mirror may be used to ignite/ablate all modules using a single laser pulse. FIG. 10 illustrates an exemplary embodiment of an ignition/ablation propulsion system having multiple ignition chambers 40 positioned along a single propellant tape 25. In various embodiments, multiple ignition chambers 40 may share one or more pairs of storage feed and storage takeup reels, one laser, and one controller. |
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abstract | A particle beam irradiation apparatus includes a synchrotron, two scanning electromagnets, an beam delivery apparatus for outputting an ion beam extracted from the synchrotron, and an accelerator and transport system controller, and a scanning controller. These controllers stop the output of the ion beam from the beam delivery apparatus; in a state where the output of the ion beam is stopped, change the irradiation position of the ion beam by controlling the scanning electromagnets; and after this change, control the scanning electromagnets to start the output of the ion beam from the beam delivery apparatus and to perform irradiations of the ion beam to at least one irradiation position a plurality of times based on treatment planning information. |
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description | The present invention relates generally to radiation-shielding devices for radioactive materials and, more particularly, to radiation-shielding assemblies used to enclose radioactive materials used in the preparation and/or dispensing of radiopharmaceuticals. Nuclear medicine is a branch of medicine that uses radioactive materials (e.g., radioisotopes) for various research, diagnostic and therapeutic applications. Radiopharmacies produce various radiopharmaceuticals (i.e., radioactive pharmaceuticals) by combining one or more radioactive materials with other materials to adapt the radioactive materials for use in a particular medical procedure. For example, radioisotope generators may be used to obtain a solution comprising a daughter radioisotope (e.g., Technetium-99m) from a parent radioisotope (e.g., Molybdenum-99) which produces the daughter radioisotope by radioactive decay. A radioisotope generator may include a column containing the parent radioisotope adsorbed on a carrier medium. The carrier medium (e.g., alumina) has a relatively higher affinity for the parent radioisotope than the daughter radioisotope. As the parent radioisotope decays, a quantity of the desired daughter radioisotope is produced. To obtain the desired daughter radioisotope, a suitable eluant (e.g., a sterile saline solution) can be passed through the column to elute the daughter radioisotope from the carrier. The resulting eluate contains the daughter radioisotope (e.g., in the form of a dissolved salt), which makes the eluate a useful material for preparation of radiopharmaceuticals. For example, the eluate may be used as the source of a radioisotope in a solution adapted for intravenous administration to a patient for any of a variety of diagnostic and/or therapeutic procedures. In one method of obtaining a quantity of the eluate from the generator, an evacuated container (e.g., an elution vial) may be connected to the generator at a tapping point. For example, a hollow needle on the generator can be used to pierce a septum of an evacuated container to establish fluid communication between the elution vial and the generator column. The partial vacuum of the container can draw eluant from an eluant reservoir through the column and into the vial, thereby eluting the daughter radioisotope from the column. The container may be contained in an elution shield, which is a radiation-shielding device used to shield workers from radiation emitted by the eluate after it is received in the container from the generator. After the elution is complete, the activity of the eluate may be calibrated by transferring the container to a calibration system. Calibration may involve removing the container from the shielding assembly and placing it in the calibration system to measure the amount of radioactivity emitted by the eluate. A breakthrough test may be performed to confirm that the amount of the parent radioisotope in the eluate does not exceed acceptable tolerance levels. The breakthrough test may involve transfer of the container to a thin shielding cup (e.g., a cup that effectively shields radiation emitted by the daughter isotope but not higher-energy radiation emitted by the parent isotope) and measurement of the amount of radiation that penetrates the shielding of the cup. After the calibration and breakthrough tests, the container may be transferred to a dispensing shield. The dispensing shield shields workers from radiation emitted by the eluate in the container as the eluate is transferred from the container into one or more other containers (e.g., syringes) for use later in the radiopharmaceutical preparation process. Dispensing shields are generally lighter weight and easier to handle than elution shields for the dispensing process because each of the containers may be used to fill multiple containers (e.g., off and on over the course of a day) and it is generally desirable to place the shielded container upside down on a work surface (e.g., tabletop surface) during the idle periods between transfer of the eluate into one container and the next. Prior art elution shields are generally not conducive for use as dispensing shields because, among other reasons, they may be unstable when inverted. For example, some elution shields have a heavy base that results in a relatively high center of gravity when the elution shield is upside down. Further, some elution shields have upper surfaces that are not adapted for resting on a flat work surface (e.g., upper surfaces with bumps that would make the elution shield unstable if it were placed on a flat surface upside down). Radiopharmacies have addressed this problem by maintaining a supply of elution shields and another supply of dispensing shields. This solution necessitates a transfer of the container from an elution shield to a dispensing shield, which can undesirably expose a worker to radiation. The same generator may be used to fill a number of containers before the radioisotopes in the column are spent. The volume of eluate needed at any time may vary depending on the number of prescriptions that need to be filled by the radiopharmacy and/or the remaining concentration of radioisotopes in the generator column. One way to vary the amount of eluate drawn from the column is to vary the volume of evacuated containers used to receive the eluate. For example, container volumes ranging from about 5 mL to about 30 mL are common and standard containers having volumes of 5 mL, 10 mL, or 20 mL are currently used in the industry. A container having a desired volume may be selected to facilitate dispensing of a corresponding amount of eluate from the generator column. Unfortunately, the use of multiple different sizes of containers is associated with significant disadvantages. For example, a radiopharmacy must either keep a supply of labels, rubber stoppers, flanged metal caps, spacers and/or lead shields in stock for each type of container it uses, or use shielding devices that can be adapted for use with containers of various sizes. One solution that has been practiced is to keep a variety of different spacers on hand to occupy extra space in the radiation shielding devices when smaller containers are being used. Unfortunately, this adds to the complexity and increases the risk of confusion because the spacers can get mixed up, lost, broken, or used with the wrong container and are generally inconvenient to use. For instance, some conventional spacers surround the sides of the containers in the shielding-devices, which is where labels may be attached to the containers. Accordingly, the spacers may mar the labels and/or adhesives used to attach the labels to the container resultantly causing the spacers to stick to the sides of the container or otherwise gum up the radiation-shielding device. Thus, there is a need for improved radiation-shielding assemblies and methods of handling containers containing one or more radioisotopes that facilitates safer, more convenient, and more reliable handling of radioactive materials produced for nuclear medicine. One aspect of the present invention is directed to a radiation-shielding assembly that may be used to shield a radioactive material in an elution process and/or in a dispensing process. The assembly includes a body having a cavity and an opening into the cavity defined therein. The assembly also includes a cap adapted for releasable attachment (e.g., via magnetism) to the body when the cap is in a first orientation relative to the body and for non-attached engagement with the body when the cap is in a second orientation relative to the body. Incidentally, a “non-attached engagement” or the like means that first and second structures interface but are not attached. An example of a non-attached engagement would be the interface of a drinking cup disposed on a coaster. Another aspect of the invention is directed to use of a radiation-shielding assembly. In this method, a cap of the radiation-shielding assembly is releasably attached to a body of the assembly to cover an opening into the body and to limit escape of radiation from inside the assembly. The cap is removed from the body and placed on an appropriate support surface (e.g., working surface). The body is inverted and placed on top of the cap so that the cap is in a different orientation relative to the body than it was when it was releasably attached to the body, thereby causing the cap and body to be in non-attached engagement. The body may be lifted from the cap to expose the opening. Another aspect of the invention is directed to a radiation-shielding assembly that can be used to shield an eluate (e.g., solution that includes a radioisotope from a radioisotope generator). The assembly has a body at least partially defining a cavity for receiving the eluate. There is an opening through the body into the cavity at an end of the body. The body is designed/configured to limit escape of radiation emitted by the radioisotope from the elution shield through the body. The assembly also has a base that may be releasably secured to the body at a second end thereof. The base has a sidewall extension portion aligned with the circumferential sidewall when the base is secured to the body. The sidewall extension portion of the base has a relatively lighter-weight construction in comparison to the circumferential sidewall of the body. For instance, the sidewall extension portion of the base may be made of a material exhibiting a first weight density, and the circumferential sidewall of the body may be made of another material having a second weight density greater than the first weight density. Another aspect of the invention is directed to a method of making an elution shield for a radioisotope received from a radioisotope generator. A body of the elution shield includes a radiation-shielding material and is formed to have a cavity for receiving the radioisotope therein. A base of the elution shield includes a material that would be substantially transparent to radiation emitted by the radioisotope. The material of the base is a relatively lighter-weight material than the radiation-shielding material of the body. The base is formed to connect to the body and extend the overall length of the elution shield to a length greater than the length of the body. Still another aspect of the invention is directed to a radiation-shielding assembly for holding any one of a set of containers that have different heights and that may be used to contain a radioactive substance. The assembly has a body at least partially defining a cavity for receiving a container. The assembly is preferably constructed to limit the escape of radiation emitted in the cavity from the assembly. The cavity has first and second opposite ends. The assembly also has a spacer that can be at least partially disposed in the cavity (e.g. at or near the second end of the cavity). The spacer is selectively adjustable to change the amount of space between a support surface of the spacer and the first end of the cavity by translation of the support surface so the support surface positions the containers in substantially the same location relative to the first end of the cavity. Yet another aspect of the invention is directed to a method of using a radiation-shielding assembly to handle containers that have different heights and which are used to hold a radioactive substance. A first container is placed in a cavity defined in the radiation-shielding assembly. A spacer is associated with the cavity and is utilized to position the first container at a predetermined location relative to an end of the cavity. The first container is subsequently removed from the cavity. The spacer is adjusted by moving the spacer along an axis of the cavity to change the amount of space between the spacer and the end of the cavity. A second container having a different height than the first container is placed in the cavity. The adjustment of the spacer results in the second container being positioned at substantially the same predetermined location as the first container was relative to the end of the cavity. Still another aspect of the invention is direction to a radiation-shielding assembly for container holding a radioactive eluate. The assembly has a body at least partially defining a cavity for receiving the container. There is an opening through the body into the cavity. The opening is sized to permit the container to be placed into and removed from the cavity. The body of the assembly is constructed to limit escape of radiation from the radioactive material through the body. The assembly also includes a locator in the cavity opposite the opening for at least assisting in locating the container in a predetermined position in the cavity. The locator may be characterized as a guide that can interface with one end of the container and that is shaped so that, upon interfacing with the end of the container, the collar may be used to at least generally steer or direct the container to the predetermined position in the cavity. The locator may include and of a wide range of materials. For instance, in some embodiments, the locator may include or be made entirely from a material that is substantially transparent to radiation. Another aspect of the invention is directed to a method of making a radiation shielding assembly for a container containing a radioactive eluate. A body of the assembly includes shielding material capable of substantially limiting passage of radiation through the material. The body is formed with a cavity for receiving the container of radioactive eluate. A locator is formed from a material that is substantially transparent to radiation so that the locator can be received in the cavity and engage the container when placed in the cavity to locate the container in (e.g., guide or steer the container toward) a predetermined position relative to the body in the cavity. Still another aspect of the invention is directed to a radiation-shielding assembly for holding any one of a set of containers having different heights that are used for containing a radioactive substance. The assembly has a body at least partially defining a cavity for receiving a container. The assembly also has a spacer adapted to be at least partially received in the cavity. The spacer can selectively be placed in the cavity to occupy space in the cavity to adapt the assembly for use with at least one of the smaller containers or removed from the cavity to adapt the assembly for use with at least one of the larger containers. The assembly may also have a base adapted for releasable connection to the body. The base may have a stowage receptacle defined therein that can receive the spacer when the spacer is removed from the cavity. Yet another aspect of the invention is a method of using a radiation-shielding assembly to hold containers having different heights that are used for containing a radioactive substance. A spacer is placed in a cavity of the assembly to adapt the assembly for use with a first container. The first container may be substantially enclosed in the cavity. The first container is subsequently removed from the cavity. The spacer may also be removed from the cavity to adapt the assembly for use with a second container that is taller than the first container. When not in use, the spacer may be stowed in a stowage receptacle formed in the assembly. The second container may be substantially enclosed in the cavity. Various refinements exist of the features noted in relation to the above-mentioned aspects of the present invention. Further features may also be incorporated in the above-mentioned aspects of the present invention as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to any of the illustrated embodiments of the present invention may be incorporated into any of the aspects of the present invention alone or in any combination. Corresponding reference characters indicate corresponding parts throughout the figures. Referring now to the figures, first to FIGS. 1-3 in particular, one embodiment of a radiation-shielding assembly of the present invention is shown as a rear-loaded dual-purpose radioisotope elution and dispensing shield, generally designated 101. The assembly 101 may enclose a container (e.g., eluate vial) containing a radioisotope (e.g., Technetium-99m) that emits radiation in a radiation-shielded cavity in the assembly, thereby limiting escape of radiation emitted by the radioisotope from the assembly. Thus, the assembly may be used to limit the radiation exposure to workers handling of one or more radioisotopes or other radioactive material. As shown in FIGS. 2 and 3, the illustrated assembly 101 generally has a body 103, a cap 105, a collar 107, and a base 109. The body 103 may include a circumferential sidewall 115 partially defining a cavity 117 adapted to receive a container 119 (shown in phantom). The cap 105 may be releasably attached to one end of the body 103 while the base 109 may be releasably attached to the other end of the body. The collar 107 may be received in the cavity 117, if desired, to help guide the container 119 into a desired position in the body 103 as it is loaded into the assembly 101. When assembled together, as shown in FIGS. 1 and 3, the body 103, cap 105, and base 109 may be used to enclose the container 119 in the cavity 117 of the assembly 101 and form a shielding unit that limits escape of radiation in the cavity 117 from the assembly 101. The sidewall 115 of the body 103 shown in the figures is substantially tubular, but the sidewall can have other shapes (e.g., polygonal) without departing from the scope of the invention. The sidewall 115 may be adapted to limit escape of radiation emitted in the cavity 117 from the assembly 101 through the sidewall. For example, in one embodiment the sidewall 115 includes a radiation-shielding material (e.g., lead, tungsten, depleted uranium or another dense material). The radiation-shielding material can be in the form of one or more layers (not shown). Some or all of the radiation-shielding material can be in the form of substrate impregnated with one or more radiation-shielding materials (e.g., a moldable tungsten impregnated plastic). Those skilled in the art will know how to design the body 103 to include a sufficient amount of one or more selected radiation-shielding materials in view of the amount and kind of radiation expected to be emitted in the cavity and the applicable tolerance for radiation exposure to limit the amount of radiation that escapes the assembly 101 through the sidewall 115 to a desired level. One end of the body 103 may define a first opening 121 to the cavity 117 and a second end of the body 103 may define a second opening 123 to the cavity 117, as shown in FIG. 3. The second opening 123 may be sized greater than the first opening 121. For example, the first opening 121 can be sized to prevent passage of the container 119 therethrough and yet permit passage of at least a tip of a needle (not shown) therethrough (e.g., a needle on a tapping point of a radioisotope generator). The body 103 shown in the figures, for example, includes an annular flange 127 extending radially inward from the sidewall 115 near the top of the sidewall. (As used herein the terms “top” and “bottom” are used in reference to the orientation of the assembly 101 in FIG. 3 but does not require any particular orientation of the assembly or position of component parts.) An inside edge 129 of the flange 127 defines the first opening 121, which may be a substantially circular opening. The flange 127 may have a chamfer 131 to facilitate guiding of the tip of a needle toward a pierceable septum (not shown) of the container 119 received in the cavity. The flange 127 may be integrally formed with the sidewall 115 or manufactured separately and secured thereto. The flange 127 may include a radiation-shielding material, as described above, to limit escape of radiation from the assembly 101. However, the flange 127 can be substantially transparent to radiation without departing from the scope of the invention. The second opening 123 may be sized to permit passage of a container 119 therethrough for loading and unloading of containers from the assembly 101. The cap 105 may be removed from the assembly 101 as shown in FIG. 5 so that the container 119 in the cavity 117 of the assembly can be fluidly interconnected with a radioisotope generator through the now exposed opening 121. Incidentally, “fluidly interconnected” or the like refers to a joining of a first component to a second component or to one or more components which may be connected with the second component, or a joining of the first component to part of a system that includes the second component so that a substance (e.g., an eluant and/or eluate) may pass (e.g., flow) at least one direction between the first and second components. The cap 105 of the embodiment shown in the figures is reversible. When the cap 105 is in a first orientation relative to the body 103 (shown in FIGS. 1 and 3), the cap may be releasably attached to the body. When the cap 105 is in a second orientation relative to the body 103 (e.g., inverted as shown in FIGS. 6 and 6A), the cap 105 may be adapted for non-attached engagement with the body 103. More specifically, FIGS. 6 and 6A show the cap in the same orientation as in FIGS. 1-3 while the body has been inverted relative to the cap and placed upside down on the cap. The configuration of the assembly 101 in FIG. 3 may be characterized by some to be convenient for carrying the container 119 of radioactive eluate in the cavity 117 from one place to another with less concern about the cap 105 accidentally falling off the body 103 and unnecessarily exposing people to radiation than if the cap 105 were simply set unattached on top of the assembly 101. The configuration of the assembly 101 in FIGS. 6 and 6A may be found to be convenient for storing the container 119 of radioactive eluate in an inverted position during idle time between the dispensing of eluate from the container 119 in the assembly into another container (e.g., a syringe) used downstream in the radiopharmaceutical preparation process. In addition, some users may find that orientation convenient because it allows a person to access the container 119 simply by lifting the body 103 off the cap 105 to expose the first opening 121. For example, the container 119 can be accessed by lifting the body 103 with a single hand as shown in FIG. 7, leaving the other hand free to perform another action (e.g., hold a syringe) in preparation for the dispensing process. There are a number of ways to design a cap 105 to be releasably attachable to the body 103 in the first orientation and adapted for non-attached engagement with the body 103 in the second orientation. The cap 105 shown in FIGS. 4 and 4A, for example, includes a magnetic portion 137 that attracts the body 103 when the cap is in the first orientation, thereby resisting movement of the cap 105 away from the body. In some embodiments, the body 103 may be constructed of a material (e.g., an alloy comprising one or more magnetic metals) that is attracted by the magnetic portion 137 of the cap 105. In other embodiments, the body 103 includes a material having a relatively weaker attraction or no attraction to the magnetic portion 137 of the cap 105 and an attracting element (not shown) made of a material that has a relatively stronger attraction to the magnetic portion (e.g., iron or the like) molded into or otherwise secured to the body to enable the magnetic portion of the cap to attract the body. When the cap 105 is in the second orientation, however, the attraction of the magnetic portion 137 of the cap to the body 103 is sufficiently attenuated (e.g., by an increase in distance between the body and the magnetic portion of the cap, magnetic “shielding”, etc.) so that the weight of the cap is sufficient to freely separate the cap from the body when one of the body and the cap is urged away from the other. As shown in FIGS. 3 and 6A, for example, the cap 105 may be constructed so that the magnetic portion 137 thereof is positioned adjacent (e.g. in contact with) the body 103 when the cap engages the body in the first orientation (FIG. 3) and separated from the body (e.g., by a substantially non-magnetic material 139) when the cap engages the body in the second orientation (FIG. 6A). The cap and/or the body may be equipped with detents, snaps and/or friction fitting elements or other fasteners that are operable to releasably attach the cap to the base without use of magnetism in the first orientation and which are substantially inoperable to attach the cap to the body in the second orientation without departing from the scope of the invention. The cap 105 may be adapted to limit escape of radiation emitted in the cavity 117 from the assembly 101 through the first opening 121 when the cap is releasably attached to the body 103 in the first orientation and when the cap is in non-attached engagement with the body in the second orientation. For example, the cap 105 may include one or more radiation-shielding materials (not shown), as described above. Those skilled in the art will be able to design the cap 105 to include a sufficient amount of one or more radiation-shielding material to achieve the desired level of radiation shielding. In order to reduce costs, radiation-shielding materials may be positioned at the center of the cap 105 (e.g., in registration with the first opening 121 when the cap is positioned relative to the body as shown in FIGS. 3 and 6), and the outer circumference of the cap may be made from less expensive and/or lighter-weight non-radiation-shielding materials, but this is not required for practice of the invention. The collar 107 (which, in some case, may be referred to as a container “locator” of sorts) may be placed in the cavity 117 to guide the container 119 into a desired and/or predetermined position as it is loaded into the cavity. For example, the collar 107 may be press fit into the cavity 117 so that the friction between the body 103 and the collar tends to hold the collar in the cavity. In other embodiments, the collar 107 may be secured to the body 103 by an adhesive or other suitable method of attachment. In yet other embodiments, the collar 107 may be an integral component of the body 103. The collar 107 may be adapted to assist in aligning the top of a container 119 with the first opening 121 of the body 103 to facilitate piercing of the container's septum by the tip of a needle on a radioisotope generator when the container is disposed in the cavity 117 of the body 103. In some embodiments, alignment of the top (e.g., mouth) of the container 119 with the first opening 121 may require the top of the container to be centered in the cavity 117, but the predetermined position to which the collar is constructed to guide the container can vary depending on the configuration of the particular assembly. In the embodiment shown in FIG. 3, the collar 107 may be position in the cavity 117 adjacent the first opening 121 and opposite the second opening 123. Referring to FIG. 3 in conjunction with FIGS. 17A-B, the collar 107 has an aperture 145 spanning between first and second sides of the collar. A first aperture opening is defined at the side of the collar 107 facing the second opening 123 of the body 103, and a second aperture opening of the collar is defined at the side of the collar facing the first opening 121 of the body. The aperture 145 may receive at least a part of a container 119 as it is loaded into the cavity through the second opening 123 in the body 103. The aperture 145 is shaped so that the collar 107 guides or steers the container 119 toward the predetermined position upon engagement of the inside of the collar 147 with the leading end of the container as it is being loaded into the cavity 117. For instance, the first opening of the aperture 145 may be greater in size than the second opening of the aperture. The aperture 145 of the collar 107 shown in FIGS. 17A and 17B is somewhat analogous to a funnel in that it is tapered. The collar 107 can have a different shape (e.g., be shaped to define a stepped or tiered aperture 145′ like the collar 107′ shown in FIGS. 18A and 18B) without departing from the scope of the invention. The top of the aperture 145 defined in the collar 107 may be shaped to engage or at least generally interface with about the top third of a cap 119a of the container 119 being held in the cavity 117, as shown in FIG. 3. It should be noted that other embodiments of the top of the aperture 145 may be shaped to engage or at least generally interface with more or less than about the top third of the cap 119a on the container 119. As illustrated, the collar 107 is operable to align (e.g., center) a septum of the container 119 with the first opening 121. The portion of the container 119 that is engaged by the collar may be varied in size and/or location without departing from the scope of the invention. The collar 107 may be constructed of any appropriate material, such as a relatively inexpensive, lightweight, durable, low-friction material (e.g., polycarbonate). Moreover, the material may be substantially transparent to radiation. Indeed, since the body 103 of the assembly 101 generally includes radiation-shielding material, it may be undesirable to include radiation-shielding material in the collar 107 as well. In other words, the collar 107 of some embodiments may include radiation-shielding material only to the extent such radiation-shielding material is needed to attain a desired and/or required level of radiation protection for a specific application. Use of a material that is transparent to radiation for the make-up of the collar 107 may beneficially allow the weight and/or cost of the assembly to be reduced. Those skilled in the art will appreciate that the cost of machining a cylindrical cavity 117 in the body 103 may tend to be less than the cost of machining a cavity in the body shaped to form one or more positioning structures (e.g., shoulders) on the body to be used to guide containers in the same manner as the collar 107. Radiation-shielding materials can be difficult to machine and may tend to be more expensive than other materials that may be used for the collar 107. Further, the overall weight of the assembly may be reduced by making the collar 107 out of relatively lighter-weight material instead of relatively heavier-weight materials that may be used to make the body 103. It is understood, however, that the body 103 can be manufactured by any method (e.g., molding) without departing from the scope of the invention. Moreover, use of other types of locators instead of a collar is considered to be within the scope of the invention. Still further, some embodiments of the invention have collars that include radiation-shielding materials. The base 109 may be releasably secured to the body 103. As best seen in FIGS. 12 and 13, the base 109 shown in the figures includes an extension element 161, a base shielding element 163, and a spacer system 165. The extension element 161 may be a generally tubular structure having an open top end 171 adapted for making a releasable connection to the body 103 (e.g., adjacent the second opening 123) and a closed bottom end 173. The extension element 161 may be constructed of one or more relatively inexpensive, lightweight, durable materials, such as high-impact polycarbonate materials (e.g., Lexan®), nylon, and the like. The bottom end 173 of the extension element 161 may be outwardly flared to provide a wider footprint for added stability when the assembly 101 is placed base down on a work surface (as shown FIG. 1). The extension element 161 may be used to lengthen the assembly 101, including the combined length of the body 103 and the base 109. For example, the extension element 161 may include a circumferential sidewall 181 generally corresponding to the circumferential sidewall 115 of the body 103 as shown in FIG. 1. As those skilled in the art know, some radioisotope generators are designed to work with a shielding assembly having a particular minimum length (e.g., six inches). The extension element 161 may be used in combination with a body 103 that would otherwise be too short for a particular radioisotope generator to satisfy the minimum length requirement of that generator. The base extension element 161 may be transparent to radiation because other parts of the assembly 101 can be designed to achieve the desired level of radiation shielding. Use of a relatively lighter-weight (e.g., non-radiation-shielding) extension element 161 to provide the required length allows the assembly 101 to be lighter and/or less expensive compared to a similar assembly that is constructed of relatively heavier-weight and/or more expensive materials (e.g., radiation-shielding materials) along the entirety of the minimum length required by a particular radioisotope generator. There may be a void (illustrated herein as a receptacle 203) in the base for additional weight reduction. For example, in one embodiment of the invention, the overall weight is no more than about 4 pounds. In another embodiment, the weight is no more than about 3 pounds. Use of the relatively lightweight extension element 161 may also shift the center of gravity of the assembly 101 toward the end of the body 103 defining the first opening 121, making the assembly more stable when inverted for use as a dispensing shield (See, FIG. 6). The base 109 may be adapted for being releasably attached to the body 103 by a quick turn connection 191 (e.g., a connection in which the base may be secured to and/or released from the body by twisting the base relative to the body by no more than about 180 degrees) as is shown in FIG. 9. When the base 109 is twisted to release it from the body 103, the quick turn connection 191 may be adapted to provide a positive indication that the base has been twisted far enough relative to the body to permit the assembly 101 to be opened. By enabling separation of the base 109 from the body 103 by twisting the base through a relatively small angle relative to the body (e.g., about 45 degrees in the illustrated embodiment) and/or providing a positive indication that the assembly 101 can be opened by pulling the base away from the body, some embodiments of the invention may help reduce the risk of accidentally dropping the base (and perhaps letting a container filled with and/or contaminated by radioactive material fall out of the body) in the course of opening the assembly, such as might occur with a conventional shielding assembly if a worker adjusts his or her grip on the assembly to twist the base some more when, unbeknownst to the worker, the base has already been twisted far enough to release of the base from the body. Referring to the embodiment shown in FIG. 9, for example, the quick turn connection 191 attaching the base extension element 161 and body 103 may be a “bayonet” type connection. The base extension element 161 may include a plurality of connecting elements 193 (e.g., lugs, threads, or the like) adapted for establishing a connection with a corresponding plurality of connecting elements 195 on the bottom end of the body 103. In one embodiment of the invention, the contact angle “α” (FIG. 10C) between corresponding connecting elements 193, 195 may be selected to provide a secure connection that makes it unlikely that the assembly 101 will be unintentionally opened as it is jostled about during handling and/or that makes it unlikely that the quick connection 191 will jam when someone tries to open the assembly. Referring to FIGS. 10A-10C, for instance, the contact angle “α” between the lugs 193 on the base extension element 161 and the mating lugs 195 on the body 103 may range from a relatively less steep angle that is empirically demonstrated to allow separation of the base 109 from the body without jamming to a relatively steeper angle that is about equal to the arctangent of the coefficient of friction between the mating connecting elements, both of which may vary depending on the materials used to form the connecting elements. As the coefficient of friction decreases, the contact angle “α” may be made less steep. In some embodiments, the coefficient of friction may be between about 0.1 to about 0.2. In other embodiments, the coefficient of friction is between about 0.12 and about 0.15. In still other embodiments, the coefficient of friction is about 0.12. The contact angle “α” may range from about 2 degrees to about 10 degrees in some embodiments. In other embodiments, the contact angle “α” may range from about 5 degrees to about 10 degrees. It is understood that a quick turn threaded connection (e.g., a multi-start threaded connection) between the body 103 and the base 109 can be provided with substantially the same contact angles discussed with reference to the bayonet connection 191 to reduce the risk of unintentional opening of the assembly and to reduce the likelihood of jamming when someone tries to open the assembly 101. Incidentally, some embodiments of the invention may exhibit contact angles and/or coefficients of friction that fall outside of the ranges described above. The quick turn connection 191 shown in FIGS. 9-10C may provide a positive indication when the base 109 has been rotated sufficiently relative to the body 103 to permit opening of the assembly 101 by limiting further rotation of the base when the base is capable of being separated from the body. For example, the lugs 193, 195 may be adapted to function as stops when the base 109 has been rotated far enough to open the assembly 101. Referring to FIGS. 10A-10C, for example, in one embodiment, the generally trapezoidal lugs 193, 195 on the base 109 and body 103 may be sized and spaced so that the lugs on the base may pass between the lugs on the body (FIGS. 10A and 10B). The quick turn connection 191 may be established by rotating the base 109 relative to the body 103 to cause the lugs 193, 195 to engage one another as shown in FIG. 10C. As the base 109 is rotated in the opposite direction to open the assembly 101, the lugs 193, 195 reach a point at which the lugs on the base may pass between the lugs on the body. At that point (FIG. 10B), the lugs 193 on the base 109 abut the lugs 195 on the body 103, thereby limiting the amount of rotation of the base that is possible. When a person opening the assembly 101 feels the lugs 193, 195 contact (e.g., “bump into”) each other, he or she knows that the base 109 can be separated from the body 103 without any additional rotation of the base relative to the body. FIG. 10D shows another embodiment of a quick turn connection 191′ in which the lugs 193′ on the base 109′ include ribs 193a′ extending their taller side. There may be clearance between the lugs 193′, 195′ (except for the ribs 193a′), but the lugs 195′ bump into the ribs 193a′ to provide a positive indication that the assembly 101 can be opened. The base shielding element 163 may be connected (either directly or indirectly as shown in FIG. 3) to the base extension element 161 so that connection of the base extension element to the body 103 interconnects the base shielding element to the body. The base shielding element 163 may be operable to limit escape of radiation emitted in the cavity 117 from the assembly 101 through the second opening 123 when the base extension element 161 is connected to the body 103. As shown in FIG. 3, for example, the base shielding element 163 may include a plug adapted to be slidably received by the second opening 123 of the body 103 into the cavity 117. The base shielding element 163 may be adapted to absorb and/or reflect radiation over an area that is substantially coextensive with the second opening 123, for example, by being configured as a plate having substantially the same shape and size as the opening. In some embodiments of the invention, the base shielding element may be adapted to substantially cover the second opening 123 without being received therein. The base shielding element 163 may include one or more radiation-shielding materials (not shown), as described above. Those skilled in the art will know how to design a base shielding element 163 to include a sufficient amount of one or more radiation-shielding materials to limit escape of radiation from the assembly 101 through the second opening 123 to a desired level. The spacer system 165 may include an adjustable spacer 201, which may be at least partially received in the cavity 117 for selectively configuring the assembly 101 to hold a container selected from a set of containers including containers having different heights (e.g., different volumes). Referring to the embodiment shown in the figures, for example, the spacer 201 may be slidably mounted in the receptacle 203 in the base 109 (e.g., a substantially cylindrical receptacle in the base extension element 161). The receptacle 203 in the base 109 may be adjoin the second opening 123 into the cavity 117 of the body 103 when the base is secured to the body, thereby positioning the spacer 201 for slidable extension into and retraction out of the cavity 117. The base shielding element 163, which may define a support surface for the container 119 when it is received in the cavity 117, may be secured (e.g., by a threaded connection or other method of attachment) to or integral with the spacer 201. By selective positioning of the spacer 201 with respect to the first opening 121, the position of the base shielding element 163 relative to the first opening 121 of the body 103 can be changed to position the top of each of the containers 119 at substantially the same location relative to the first opening, notwithstanding their different heights. The spacer 201 can be mounted in the assembly 101 in a variety of different ways. For example, the spacer 201 shown in the figures has a substantially cylindrical surface (e.g., outer surface) having a helical channel 205 defined therein. A detent 209 received in the channel 205 may be another component of the spacer system 165. In some embodiments, like the one shown in the figures, for instance, the detent 209 is associated with (e.g., mounted on) the base extension element 161, but in other embodiments the detent may be associated with other elements of the assembly 101. The detent 209 may be substantially fixed relative to the body 103 (e.g., when it is mounted on the base 109 while it is secured to the body). The detent 209 of the embodiment shown in the figures is a ball detent plunger. The ball detent plunger may be a threaded member 211 having a loosely captured ball 213 therein. A spring (not shown) may be positioned in the threaded member 211 to bias the ball 213 to a position in which a portion of the ball projects outward from an end of the threaded member. The threaded member 211 may be screwed into the base extension element 161 so that the end of the threaded member to which the ball 213 is biased is received in the channel 205. Other detents could be used instead, however. The detent 209 might be characterized as a cam, and the spacer 201 a cylindrical cam follower. The detent 209 engages one side of the helical channel 205 upon rotation of the spacer 201, producing movement (e.g., along an axis 197 of the cavity 117) of the spacer relative to the receptacle 203 in the base extension element 161. Depending on the direction of the rotation, the spacer 201 may be moved out of or into the receptacle 203, corresponding to translation farther into the cavity 117 and out of the cavity in the assembly 101, respectively. Further, as shown in FIGS. 11 and 12, a plurality of recesses 217 adapted to engage the tip of the ball detent plunger 209 may be formed in the bottom of the helical channel 205. Only some of these recesses 217 are shown in the figures. Each of the recesses 217 may be aligned with the ball 213 of the ball detent plunger 200 when the spacer 201 is in one of the positions in which the spacer is adjusted for use with a particular one of the containers in the set. Thus, when the spacer 201 is moved into that position, the tip 213 of the ball detent plunger 209 may engage the respective recess 217 producing an audible click and/or tactile feedback to indicate that the spacer is in position. The recesses 217 may help to hold the spacer 201 in the selected position. Moreover, the spacer 201 may include markings 221 indicating the different heights of the containers positioned on the spacer relative to the helical channel 205 so that when the spacer is positioned for use with one of the containers, the corresponding marking is in a predetermined position in which it is visible while the other markings are obscured from view. In the embodiment shown in the figures, for example, a window 223 is formed in the base 109 below the ball detent plunger 209. Markings 221 are located on the outer surface of the spacer 201 at positions that are offset from (e.g., below) the respective recess 217 an amount corresponding to the amount of offset between the detent 209 and the window 223. When the ball 213 of the ball detent plunger 209 is engaged with one of the recesses 217, the corresponding marking 221 is visible in the window 223. The remaining markings 221 are covered by the base extension element 161 so workers can tell what kind of container is held in the assembly 161 by looking through the window 223 to view the corresponding marking 221, thereby obviating the need to open the assembly 101 to determine or confirm what kind of container is in the assembly. FIGS. 14A-14C and 15A-15C, for example, show a sequence of adjustment of the spacer system 165 for three containers 119′, 119″, 119′″ having three different heights. FIG. 14A shows the spacer 201 positioned for use with a 20 mL container 119′ (FIG. 15A), as indicated by the lowered position of the spacer and the marking 221 of “20” on the spacer that is visible in the window 223 through the base extension element 161. By twisting the spacer 201 relative to the base extension element 161 generally about a central longitudinal axis of the base extension element, the spacer can be raised to adapt the assembly to hold a shorter 10 mL container 119″ (FIG. 15B). The spacer 201 is shown in this position in FIG. 14B, in which the marking 221 “10” is visible in the window 223 and the spacer has been raised above its position in FIG. 14A. By twisting the spacer 201 even more, the spacer rides farther upward on the ball detent plunger 209 and is thereby raised to adapt the assembly 101 for use with an even shorter 5 mL container 119′″ (FIG. 15C). The spacer 201 is shown in this position in FIG. 14C, in which the marking 221 “5” is visible in the window 223 and the spacer has been raised above its position in FIG. 14B. When the spacer 201 is adjusted to the desired position, the base 109 may be connected to the body 103 to enclose a container 119 in the assembly 101. FIGS. 15A-15C show a 20 mL, 10 mL, and 5 mL container 119′, 119″, 119′″ enclosed in the assembly 101, respectively, with the spacer 201 adjusted accordingly. As shown in FIGS. 15A-15C, the ball detent plunger 209 is engaged with one of the recesses 217 in the helical channel 205 at each of the three positions corresponding to one of the heights of the containers 119′, 119″, 119′″, providing indexed movement of the spacer 201 from a position suitable for use with one of the containers to a position suitable for use with a different one of the containers. It is understood that other constructions for adapting the assembly to work with containers having different heights may be used within the scope of the present invention. Referring to FIG. 16, a second embodiment of a spacer 201′ suitable for use with the assembly 101 shown in FIGS. 1-3, may include a first helical channel 205a′ and a second helical channel 205b′. The first channel 205a′ may be calibrated for use with a first set of containers (e.g., U.S. standard containers) and the second channel 205b′ may be calibrated for use with a second set of containers (e.g., European standard containers). Recesses 217′ and markings 221′ may be provided for each of the channels 205a′, 205b′ in the same way described for the spacer 201 describe previously. This allows the same assembly 101 to be used for indexed movement of the spacer 201′ for various different sets of containers. In order to switch from one set of containers to another, the ball detent plunger 209 is removed from one of the helical channels 205a′, 205b′ (e.g., by partially unscrewing the threaded member 211 to back the detent out of the channel), the spacer 201 is repositioned to align the other helical channel with the detent, and the ball detent plunger is replaced so that it received in the other helical channel. The base 109 of the assembly 101 shown in FIGS. 1-3 may be disconnected from the body 103 to load a container 119 (e.g., an evacuated elution vial) into the cavity. A worker may adjust the position of the spacer 201 in preparation of the assembly 101 for use with a particular container selected from a set of containers including containers having different heights. As the spacer 201 is moved into position (e.g., by grasping and turning an exposed portion of the spacer and/or base shielding element 163), the ball detent plunger 209 may engage the corresponding recess 217, producing an audible click and/or tactile sensation indicating to the worker that the spacer is in position. The position of the spacer 201 may be confirmed by looking through the window 223 in the base extension element 161 to see which of the markings 221 is visible therein. The container 119 may be loaded into the cavity 117 through the second opening 123 in the body 103. The collar 107 engages the top of the container 119 and guides it to the predetermined position in the cavity 117 (e.g., so that the septum at the top of the container is centered under the first opening 121). Then the base 109 may be reconnected to the body 103 to enclose the container 119 in the cavity 117. The spacer 201, having been adjusted for the height of the container C, holds the container so that its top is adjacent the first opening 121. Those skilled in the art will recognize that it is possible in some embodiments of the invention to adjust the position of the spacer 201 in the cavity 117 after the base 109 is connected to the assembly 101 without departing from the scope of the invention. The cap 105 may be removed for an elution process. For example, after the cap 205 is removed (FIG. 5), the container 119 may be connected to a radioisotope generator by piercing the septum of the container 119 with a needle in fluid communication with the generator using the first opening 121 for access to the container. Then the eluate may flow into the container 119 through the needle (e.g., using a vacuum pressure in the container to draw the eluate out of the generator). The needle may be removed from the container 119 when the container has received a desired volume of eluate. The cap 105 may be releasably attached to the body 103 to limit escape of radiation emitted by the eluate from the assembly 101 through the first opening 121. Because the cap 105 is held onto the body 103 (e.g., by magnetic attraction between the cap and body) the cap is less likely to be accidentally knocked off the body. The container 119 may be carried to another location, such as a calibration station, while in the assembly with the cap releasably attached to the body 103 in the first orientation. When the eluate is ready to be dispensed into other containers (e.g., syringes or other types of containers used for subsequent processing of the eluate), the cap 105 may be removed from the body 103 and placed bottom side down on a work surface. The then body 103 and base 109 of the assembly 101 may be inverted and placed on the cap 105 as shown in FIG. 6, for example. The cap 105 engages the body 103 and limits escape of radiation emitted by the eluate. When a worker is ready to transfer some of the eluate from the container 119 in the assembly to a different container, he or she may simply lift the body 103 and base 109 off the cap 105 to access the container through the first opening 121. For example, the body 103 and base 109 may be lifted off the cap 105 with a single hand (as shown in FIG. 7) and held with that hand while the eluate is transferred to the other container (e.g., by piercing the septum of the container 119 with the tip of a needle attached to a syringe and drawing the eluate into the syringe). After a desired amount of eluate has been withdrawn from the container 119 in the assembly 101, the body 103 and base 109 can be replaced on the cap 105 until more eluate is needed from the container. When the container 119 is empty or when the eluate in the container is no longer needed, the base 109 may be rotated relative to the body 103 to open the assembly 101. A worker may manually rotate the base 109 relative to the body 103. Because of the quick turn connection 191, the worker is able to release the base 109 from the body 103 by turning the base no more than about 180 degrees, which may be accomplished without requiring the worker to release his or her grip on the body or base to rotate the base farther. In one embodiment, the base 109 may be released from the body 103 by turning the base no more than about 90 degrees. In another embodiment, the base may be released from the body by turning the base no more than about 45 degrees. Moreover, when the base 109 has been rotated a sufficient amount to release the base from the body 103, the worker receives a positive indication (e.g., a tactile sensation such as an inability to rotate the base farther) that no additional turning of the base is required to separate the base from the body. This alerts the worker to the need to keep a firm grip on the base 109 and the body 103, thereby reducing the risk that the base will accidentally separate from the body and possibly let the container 119 fall out of the assembly 101. When the base 109 is separated from the body 103, the container 119 can be removed from the cavity 117. Then another evacuated container 119 may be selected and the process repeated. If the new container has a different height than the previous container, the spacer 201 may be adjusted accordingly. FIGS. 19 and 20 illustrate another embodiment of a radiation shielding assembly, generally designated 501, of the present invention. Except as noted, the illustrated assembly 501 is constructed and operates the same as the assembly 101 described above. Both assemblies 501, 101 include the same body 103, cap 105, base shielding element 163, and spacer system 165. The base 509 of the assembly 501 is similar in overall shape and function to the base 109 described above. One difference is that the base 509 comprises a radiation shielding element 521 and a non-shielding element 523. The shielding element 521 may be constructed of a relatively dense radiation shielding material (e.g., a moldable tungsten impregnated plastic material) while the non-shielding element 523 may be constructed of one or more relatively inexpensive, lightweight, durable materials, such as high impact polycarbonate materials (e.g., Lexan®), nylon, and the like. The non-shielding element 523 may surround at least a portion of the shielding element 521. For example, the shielding element 521 shown in the figures has a generally tubular portion 529. A moldable plastic material may be molded over the shielding element 521 to form the non-shielding element. One end 531 of the shielding element 521 may extend from the non-shielding element and be adapted to releasably secure the base 509 to the body 103 in substantially the same manner as the base 109 of the assembly 101 described above. As shown in FIGS. 19 and 20, the tubular portion 529 of the shielding element may transition from a relatively thicker portion 535 at the end that is closer to the body 103 when the base is releasably secured to the body to a relatively thinner portion 537 at the opposite end. Moreover, the non-shielding element 523 may extend farther away from the body 103 than the shielding element 521 when the base 509 is releasably secured to the body. Consequently, the radiation shielding provided by the base 509 may concentrated in the part of the base that is adjacent the radioactive material in the container C. Further, the center of gravity of the assembly 501 is shifted toward the end of the assembly opposite the base (compared to where it would be if the entire base were made of radiation shielding material), thereby increasing stability of the assembly when it is placed on a support surface (e.g., in a manner analogous to the way the assembly 101 described above is oriented in FIGS. 6 and 6A). The non-shielding element 523 may have an internal surface defining a plurality of inwardly extending ridges 525. The shielding element 521 may have an external surface defining a plurality of outwardly-extending ridges 527 such that the inwardly extending ridges-525 of the non-shielding element engage grooves 547 defined by the outwardly extending ridges and the outwardly extending ridges 527 engage grooves 545 defined by the inwardly extending ridges. The non-shielding element may be fixed to the shielding element by engagement of the grooves and ridges. One advantage of forming the non-shielding element 523 in an overmolding process is that the inwardly extending ridges 525 thereof may be formed in situ relative to the grooves defined by the outwardly extending ridges of the shielding element. It is understood that the base 509 shown in FIGS. 19 and 20 may be used with radiation shielding assemblies having configurations other than shown herein without departing from the scope of the present invention. Another embodiment of the invention is depicted in FIGS. 21-23C as a dual-purpose front loaded radiation shielding assembly, generally designated 301, which is suitable for use as elution and/or dispensing shield. As best seen in FIG. 22, the assembly includes a cap 305, a body 303 at least partially defining a cavity 317, a spacer 365, and a base 309. The assembly 301 is generally similar in construction and operation to the assembly 101 described above. The body 303 may be a two-part body including a main body 311 and a lid 313. The main body 311 may be a generally tubular structure having an open top end 333 defining an opening 323 (FIG. 22) sized to permit a container 119 to pass therethrough for loading and unloading of containers to and from the cavity 317 and a closed bottom end 363 adapted to limit escape of radiation emitted in the cavity 317 from the assembly 301 through the bottom of the body 303. The lid 313 is adapted to be received in the opening 323 of the main body 311. Moreover, the lid 313 defines an opening 321 that may be similar to the first opening 121 of the assembly 101 described above. The cap 305 may be similar in construction and operation to the cap 105 of the assembly 101 discussed above. The spacer 365 shown in FIGS. 22-23C may be a cylindrical sleeve having a perpendicular cross support 367 spanning the inner diameter of the spacer. The spacer 368 may be positioned as shown in 21A for use with a relatively shorter container 119′″. To adapt the assembly 301 for use with a taller container 119″, the spacer 365 may be inverted as shown in FIG. 23B. To adapt the assembly 301 for use with an even taller container 119′ the spacer 365 may be removed from the cavity. The bottom of the main body 311 may be adapted for connection (e.g., a threaded connection) to the base 309. The base of the embodiment shown in the figures may be similar in construction to the lightweight base extension element described above. The spacer system 165 described above is not used in this embodiment and the base shielding element 163 may be omitted because it would be redundant with the closed bottom end 363 of the main body 311. The base 309 defines a stowage receptacle 385 sized and shaped for storing the spacer 365 when it is not in the cavity 317. The base 309 and/or spacer 365 may be adapted to releasably secure the spacer within the stowage receptacle 385 to prevent the spacer from falling out of the stowage receptacle. For example, the base 309 may include detents 387 (FIGS. 23A-23C and 24) adapted to engage recesses 389 in the spacer to establish a snap connection between the spacer 365 and the base 309. Other fasteners could be used instead without departing from the scope of the invention. Use of the assembly 301 is generally similar to use of the assembly 101 described above. One difference in use is the manner in which containers 119 are loaded into and taken out of the cavity 317. The assembly 301 can be used for elution and dispensing just like the assembly 101 described previously. The spacer 365 may be adjusted for a particular container selected from a set of containers 119′, 119″, 119′″ having different heights. When the spacer 365 is not used (e.g., when the tallest container 119′ of the set is being held in the cavity 317) the spacer may be stowed in the stowage receptacle 385 in the bottom of the base 309, as shown in FIGS. 23C and 25. For example, the stowage receptacle 385 may be sized and shaped to permit the spacer 365 to be inserted into the stowage receptacle so that the spacer is in close fitting relationship with the sides of the receptacle. By inserting the spacer 365 into the receptacle 385, the user may engage a snap fit (as shown in the figures), a friction fit, or another suitable means of securing the spacer in the receptacle. The user may secure the spacer 365 in the receptacle 385 after it is already in the receptacle (e.g. by using a separate fastener, for example) without departing from the scope of the invention. Those skilled in the art will recognize that the radiation-shielding assemblies 101, 301 described above can be modified in many ways without departing from the scope of the invention. For example, the cap may be a non-reversible cap releasably attached to the body by a bayonet connection, a threaded connection, a snap connection or other suitable releasable fastening system without departing from the scope of the invention. The collar may be omitted if desired. The assembly can be modified to accommodate virtually any style of container. Likewise, the assembly can be modified for use with other styles of radioisotope generators. An assembly may be used only for elution or only for dispensing without departing from the scope of the invention. In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. When introducing elements of the present invention or the illustrated embodiments thereof, the articles “a”, “an”, “the”, and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including”, and “having” and variations of these terms are intended to be inclusive and mean that there may be additional elements other than the listed elements. Moreover, the use of “top” and “bottom” and variations of these terms is made for convenience, but does not require any particular orientation of the components. As various changes could be made in the above assemblies and methods without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying figures shall be interpreted as illustrative and not in a limiting sense. |
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claims | 1. A device for producing a 11C beam from a primary 12C beam, said device comprises a decelerator comprising hydrogen, H2, and configured to output said 11C beam suitable for external radiation therapy from said primary 12C beam incident on said decelerator, wherein said decelerator is a multi-medium decelerator comprising a hydrogen section followed by a decelerating section comprising a hydrogen rich material. 2. The device according to claim 1, wherein said decelerator comprises liquid H2. 3. The device according to claim 1, wherein said decelerator comprises a hydrogen section comprising said hydrogen H2 and having a thickness in an interval of from 20cm up to 70 cm. 4. The device according to claim 3, wherein said decelerator comprises said hydrogen section comprising said hydrogen H2 and having said thickness in an interval of from 20 cm up to 35 cm. 5. The device according to claim 1, wherein said decelerating section comprises a hydrogen rich plastic material. 6. The device according to claim 5, wherein said decelerating section comprises a hydrogen rich plastic material selected from the group of polyethylene and polypropylene. 7. The device according to claim 1, wherein said decelerating section comprises a hydrogen rich material selected from the group of liquid methane, liquid propane and liquid ammonia. 8. The device according to claim 1, wherein said decelerating section has a thickness selected to modulate a range of said 11C beam to reach a target depth in a subject to be irradiated by said 11C beam. 9. The device according to claim 1, wherein said decelerating section is in the form of a binary system of multiple slices of said hydrogen rich material. 10. The device according to claim 9, further comprising a slice adjuster configured to adjust a number of slices of said hydrogen rich material that are present in a beam path through said binary system to achieve a modulation of a range of said 11C beam. 11. The device according to claim 10, wherein said slice adjuster is configured to adjust said number N of slices of said hydrogen rich material to reduce said range of said 11C beam with an amount of ∑ i = 0 N - 1 2 i mm . 12. The device according to claim 1, wherein said decelerator is configured to output said 11C beam suitable for simultaneous external radiation therapy and dose delivery verification using positron emission tomography or positron emission tomography-computed tomography imaging. 13. A radiation system comprising:a device according to claim 1 to produce a 11C beam from a primary 12C beam;a set of quadropoles downstream of said device and configured to focus said 11C beam;a beam size collimator downstream of said set of quadropoles and configured to impose an angular limitation to said 11C beam; anda particle species and energy selection system downstream of said beam size collimator and configured to output a therapeutic 11C beam having a beam quality useful for external radiation therapy. 14. The radiation system according to claim 13, wherein said particle species and energy selection system comprises a set of bending magnets and a beam particle species and energy collimator. 15. The radiation system according to claim 14, wherein said particle species and energy selection system further comprises a variable wedge filter configured to reduce an energy spread of said 11C beam. 16. The radiation system according to claim 15, wherein said variable wedge filter is in the form of a variable liquid medium wedge filter with solid walls. 17. The radiation system according to claim 16, wherein said variable wedge filter is in the form of a variable liquid hydrogen, H2, wedge filter. 18. The radiation system according to claim 15, wherein said variable wedge filter comprises two axially rotatable wedges. 19. The radiation system according to claim 15, wherein said variable wedge filter is a multi-layer wedge. 20. The radiation system according to claim 13, further comprising a 12C beam provider configured to provide said primary 12C beam. 21. The radiation system according to claim 20, wherein said 12C beam provider comprises an ion source configured to produce 12C ions and a cyclotron configured to accelerate said 12C ions to form said primary 12C beam. 22. A method of producing a 11C beam from a primary 12C beam, said method comprising directing said primary 12C beam onto a device as defined in claim 1, said 11C beam suitable for external radiation therapy exiting said decelerator. 23. A radiation system comprising:a device for producing a 11C beam from a primary 12C beam, said device comprises a decelerator comprising hydrogen, H2, and configured to output said 11C beam suitable for external radiation therapy from said primary 12C beam incident on said decelerator;a set of quadropoles downstream of said device and configured to focus said 11C beam;a beam size collimator downstream of said set of quadropoles and configured to impose an angular limitation to said 11C beam; anda particle species and energy selection system downstream of said beam size collimator and configured to output a therapeutic 11C beam having a beam quality useful for external radiation therapy, wherein said particle species and energy selection system comprises:a set of bending magnets,a beam particle species,an energy collimator, anda variable wedge filter in the form of a variable liquid hydrogen, H2, wedge filter with solid walls and configured to reduce an energy spread of said 11C beam. |
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summary | ||
description | This application claims priority from U.S. Provisional Application Ser. No. 62/642,418 filed on 13 Mar. 2018, which is incorporated herein by reference in its entirety. This invention was made with government support under CA086307 awarded by the National Institutes of Health and DE-FG02-87EF60512 awarded by the Department of Energy. The government has certain rights in the invention. Not applicable. The present disclosure generally relates to methods of making radionuclides (e.g., Cu-64). Among the various aspects of the present disclosure is the provision of methods and systems for producing radionuclides (e.g., Cu-64). An aspect of the present disclosure provides for a method for manufacturing a radioisotope with improved specific activity comprising: providing a target material comprising a Ni isotope; providing a target material holder; providing a proton beam comprising a proton beam energy, a proton beam strike area, or a proton beam strike shape; or introducing the proton beam to the target material, resulting in a composition comprising a Cu radioisotope. In some embodiments, the target material comprises a target material area or target material shape; or the target material area or the target material shape has an approximately similar area or an approximately similar shape as the proton beam strike area or the proton beam strike shape, resulting in matching of the target material and the proton beam strike area or the proton beam strike shape. In some embodiments, the method comprises degrading or reducing the proton beam energy to below about 14.5 meV and focusing or constraining the proton beam. In some embodiments, the target material comprises Ni-64; the target material comprises about 80 mg or less of target material; the target material area is about 20 mm2 or less; the proton beam strike shape or the target material shape is not a circle; the proton beam strike shape or the target material shape is asymmetric; or the proton beam strike shape or the target material shape is approximately an oval shape. In some embodiments, the proton beam strike shape or the proton beam strike area is constrained to match the target material or the target material is modified to match the proton beam strike shape or the proton beam strike area. In some embodiments, the target material comprises a target material back and the target material back is mounted to the target material holder via an insulator. In some embodiments, the target material back comprises gold or platinum. In some embodiments, the target material back is keyed to orient the target material with the proton beam strike area, resulting in a keyed target material. In some embodiments, the target material holder is designed to accept a keyed target material back; or the target material holder orients the target material in the proton beam strike area of the proton beam. In some embodiments, the target material holder provides cooling or dissipates heat produced by the proton beam. In some embodiments, the target material holder provides cooling water and removes the cooling water. In some embodiments, the cooling water is deionized, having a resistivity of about 7.5 MΩ or greater than about 7.5 MΩ, preventing or reducing radioisotope contamination of the cooling water. In some embodiments, measuring the proton beam current of the target material back via a target material holder mounting flange; or recovering the target material. In some embodiments, the method results in a reduced amount of target material required to produce Cu-64 in high yield of at least about 7.5 Ci at saturation compared to the amount of target material required if the proton beam strike area or the proton beam strike shape does not match the target material area or the target material shape. In some embodiments, the Cu radioisotope has an activity of at least about 150 mCi/μA. In some embodiments, the Cu radioisotope has a specific activity of at least about 200 mCi/μg, at least about 250 mCi/μg, or at least about 300 mCi/μg. Another aspect of the present disclosure provides for a system for manufacturing a radioisotope with improved specific activity comprising: a target material; a target material holder; and a proton beam. In some embodiments, the target material comprises a target material back; the target material comprises a target material shape or a target material area; the proton beam comprises a proton beam strike area or a proton beam strike shape; and the target material area or the target material shape is approximately a similar area or shape as the proton beam strike area or the proton beam strike shape, resulting in matching of the target material and the proton beam. In some embodiments, the system comprises a material holder mounting flange capable of measuring the proton beam current of the target material back and the target material for beam steering. In some embodiments, the target material holder comprises a deionized water cooling system; the deionized water cooling system provides cooling water and removes the cooling water; or the cooling water is deionized, having a resistivity of about 7.5 MΩ or greater than about 7.5 MΩ, preventing or reducing radioisotope contamination of the cooling water. In some embodiments, the system comprises (i) Teflon™ coated vessels and Teflon™ coated connectors; (ii) vacuum drives, pressure drives, and syringe drives resulting in a flow of chemicals through the system and enabling standardization or reproducibility of target material recovery and radioisotope yield; (iii) a dissolution vessel comprising a Teflon™ gate valve for containing HCl vapor; or (iv) a digestion vessel comprising Teflon™ and a cooling fin, wherein the digestion vessel comprises a conical bottom and a Teflon™ spacer, wherein the Teflon™ spacer eliminates prevents blockage of a fluid pathway by the target material or the target material back. In some embodiments, the target material back is mounted to a target material holder via an insulator; the target material back comprises gold or platinum; the target material back is keyed to orient the target material with the proton beam strike area, resulting in a keyed target material; the target material holder is designed to accept a keyed target material back; or the target material holder orients the target material to the proton beam strike area of the proton beam. Other objects and features will be in part apparent and in part pointed out hereinafter. The present disclosure is based, at least in part, on the discovery that specific preparation and processing systems reliably manufacture Cu-64 chloride having an improved specific activity (e.g., about 200 mCi/μg or more or 250 mCi/μg) compared to previous methods. As shown herein, the enhanced specific activity was achieved using a proton particle accelerator and the Washington University designed target preparation and processing systems. The manufacturing process focused on critical steps to achieving high yield and specific activity Cu-64 chloride using specialized automation designed and built at Washington University. Although the concept of an optimal target material thickness to beam impingement area has been previously described, reducing the beam impingement area and limiting the area of the target material to achieve optimal thickness with less target material has not been discovered. The methods and systems as described herein routinely manufacture Cu-64 chloride with high specific activity and radionuclidic purity. Due to the enhanced properties, more doses can be prepared and shipped in one vial compared to other radionuclides. Cu-64 is a desirable radioisotope for its half-life and decay properties that provide unique imaging characteristics as demonstrated by the commercial success of the disclosed product. This includes multiple pharmaceutical companies seeking a reliable supply of high quality Cu-64 for their proprietary Cu-64 radiopharmaceuticals. The disclosed methods are improvements on known processes for manufacturing radionuclides (e.g., Cu-64) at increased yields and increased specific activities. Processes for the manufacture of Cu-64 are well known; see e.g. U.S. patent application Ser. No. 10/914,617, incorporated by reference in its entirety). Except as otherwise noted herein, therefore, the process of the present disclosure can be carried out in accordance with such processes. Improved Cu-64 Manufacturing System and Process The present disclosure provides for a system and optimized steps for improving the yield of high specific activity Cu-64 (see e.g., Example 1). For example, the method or system can comprise electroplating a Ni-64 target (thicker than conventional techniques); constraining a beam to optimize interaction with the target (e.g., measuring the beam shape and optimizing target shape to match the beam shape or constraining the beam shape to match the target); providing a dedicated deionized water cooling system for the target holder; Teflon™ coated vessels/connectors to allow for hands-free manipulation/separation of the Ni and Cu in 6 N HCl conditions; and/or a vacuum and syringe that drives enhanced reproducibility. Previous systems used a flat bottom digestion reactor made of Teflon™ directly heated with heat cartridges. The flat bottom and small diameter of the digestion vessel, that was just slightly larger than the target holder, required the irradiated target to be position face up to fully dissolve the Ni-64 containing Cu-64 from the gold disk target holder. This problem significantly increased the hand doses to personnel using the module. Additionally, the flat bottom digestion vessel coupled with the diameter contributed to the fluid pathway intermittently becoming blocked by the gold disk resulting in numerous failed process. The water cooled reflux condenser was too large to allow automatic dropping of the target in a standard hot cells. Additionally, the reflux condenser using room temperature water also failed to fully contain the 6 N HCl as indicated by rapid corrosion of the automation system. The rotatory pinch valves, designed to increase longevity of the tubing used for the fluid pathways were unreliable, and resulted in unacceptable leakage of chemicals used in the process and intermittently led to large dead volumes. The pinch valves also had stainless steel heads and bearing that corroded rapidly leading to a significant amount of failures and possible contamination of the Cu-64 chloride with iron. The flaws of this system prohibited it from producing high quality Cu-64 reliably and required the cyclotron facility to rely on manual techniques to manufacture Cu-64 and Cu-60 while developing another version of the module. A system was designed to address the flaws of the previous system by replacing the rotatory pinch valves with air actuated pinch valves having plastic and aluminum parts to insure they were more acid resistant. This reduced the potential of metal contamination from corroding valves having metals exposed to the processing area that were not acid resistant. The layout was optimized to reduce dead volumes and facilitate the flow of chemicals. The flat bottom digestion reactor made of Teflon™ directly heated with heat cartridges was modified to have a conical bottom that in bench top testing was an improvement but not 100% reliable. During bench top testing of this module it was decided to construct the next generation of automation using acid resistant plastics. In a version it was attempted to reduce the size of the column that contained the ion exchange resin and found that to be detrimental to the process. As a result of the difficulties with the previous designs, the cyclotron facility used effective manual remote method to process Cu-64 to produce acceptable specific activity Cu-64 chloride. The present Cu-64 separation module design corrected problems encountered with previous versions and was optimized to address issues experienced using the manual remote system. The present design uses vacuum, inert gas pressure with flow control and syringe drives to effect the flow of chemicals through the system. This is believed to be the first system to use all of the above methods for moving liquids through the automation system. While a single method could be used to effect movement of liquids, using all three for specific tasks have enabled improvement of reliability and % radiochemical yields. As described above, the digestion vessel was modified to improve reliability and eliminate the need to orient the target holder for optimal dissolution of the Ni-64 containing Cu-64 from the gold disk (target material substrate). The condenser intended to contain the HCl during heating was removed in favor of an in-house developed Teflon™ gate valve that allows the generation of pressure within the digestion vessel. This was shown to be more effective at containing the HCl acid vapor than the water-cooled reflux condenser that increases the difficulty of installing the module in a hot cell and requires an additional chilled water system. Instead of heating the Teflon™ digestion vessel directly with heat cartridges the digestion vessel is contained in aluminum housing that is heated and has cooling fin to allow for rapid cooling of the digestion vessel and contents. This allows the contents of the digestion vessel to be moved to an ion exchange column with shorter cool down periods. Additionally the bottom is conical, having a Teflon™ spacer added to the vessel to eliminate the need to orient the target and prevents blockage of the fluid pathway by the gold disk substrate. The flow pathways were optimized for precise fluid flow and easy replacement of chemical traps intended to contain acid vapor and Cu-64 in the unlikely event it aerosolized. Appropriate cleaning of the automated separation module was simplified with dedicated fluid pathways and were shown to be more effective at maintaining high specific activity of the product than disposable tubing, which is believed to be the result of small dead volume using non-disposable fluid pathways versus disposable. The digestion vessel was designed to allow for automatic delivery of the target from the cyclotron using dedicated carriers transported from the cyclotron to the hot cell using vacuum. Once in the hot cell, the carrier is automatically opened to drop the target in the digestion vessel that is then closed by the gate valve. The carrier is then returned to the cyclotron vault when needed to automatically collect the next Cu-64 target. The module drop also allows the target to be added by dropping into the digestion station from a shielded carrier. Using the disclosed process, including targetry and separation technology, high specific activity and high purity Cu-64 can be reliably produced that is suitable for radiochemistry and human use. Target Material and Target Material Substrate The system and methods described herein disclose a target material, a target material holder, a proton beam having a proton beam strike area or proton beam strike shape. The target material can be electroplated onto a substrate (e.g., a gold or metal plate) wherein the target material and substrate match or are approximately the same size, shape, and/or area as the proton beam strike size, shape, and/or area. As described herein, the target material (e.g., Ni-64) can be electroplated onto a substrate at about 100 mg or less of target material. For example, the target material can weigh between about 1 mg and about 200 mg. As another example, the target material can weigh about 1 mg; about 2 mg; about 3 mg; about 4 mg; about 5 mg; about 6 mg; about 7 mg; about 8 mg; about 9 mg; about 10 mg; about 11 mg; about 12 mg; about 13 mg; about 14 mg; about 15 mg; about 16 mg; about 17 mg; about 18 mg; about 19 mg; about 20 mg; about 21 mg; about 22 mg; about 23 mg; about 24 mg; about 25 mg; about 26 mg; about 27 mg; about 28 mg; about 29 mg; about 30 mg; about 31 mg; about 32 mg; about 33 mg; about 34 mg; about 35 mg; about 36 mg; about 37 mg; about 38 mg; about 39 mg; about 40 mg; about 41 mg; about 42 mg; about 43 mg; about 44 mg; about 45 mg; about 46 mg; about 47 mg; about 48 mg; about 49 mg; about 50 mg; about 51 mg; about 52 mg; about 53 mg; about 54 mg; about 55 mg; about 56 mg; about 57 mg; about 58 mg; about 59 mg; about 60 mg; about 61 mg; about 62 mg; about 63 mg; about 64 mg; about 65 mg; about 66 mg; about 67 mg; about 68 mg; about 69 mg; about 70 mg; about 71 mg; about 72 mg; about 73 mg; about 74 mg; about 75 mg; about 76 mg; about 77 mg; about 78 mg; about 79 mg; about 80 mg; about 81 mg; about 82 mg; about 83 mg; about 84 mg; about 85 mg; about 86 mg; about 87 mg; about 88 mg; about 89 mg; about 90 mg; about 91 mg; about 92 mg; about 93 mg; about 94 mg; about 95 mg; about 96 mg; about 97 mg; about 98 mg; about 99 mg; about 100 mg; about 101 mg; about 102 mg; about 103 mg; about 104 mg; about 105 mg; about 106 mg; about 107 mg; about 108 mg; about 109 mg; about 110 mg; about 111 mg; about 112 mg; about 113 mg; about 114 mg; about 115 mg; about 116 mg; about 117 mg; about 118 mg; about 119 mg; about 120 mg; about 121 mg; about 122 mg; about 123 mg; about 124 mg; about 125 mg; about 126 mg; about 127 mg; about 128 mg; about 129 mg; about 130 mg; about 131 mg; about 132 mg; about 133 mg; about 134 mg; about 135 mg; about 136 mg; about 137 mg; about 138 mg; about 139 mg; about 140 mg; about 141 mg; about 142 mg; about 143 mg; about 144 mg; about 145 mg; about 146 mg; about 147 mg; about 148 mg; about 149 mg; about 150 mg; about 151 mg; about 152 mg; about 153 mg; about 154 mg; about 155 mg; about 156 mg; about 157 mg; about 158 mg; about 159 mg; about 160 mg; about 161 mg; about 162 mg; about 163 mg; about 164 mg; about 165 mg; about 166 mg; about 167 mg; about 168 mg; about 169 mg; about 170 mg; about 171 mg; about 172 mg; about 173 mg; about 174 mg; about 175 mg; about 176 mg; about 177 mg; about 178 mg; about 179 mg; about 180 mg; about 181 mg; about 182 mg; about 183 mg; about 184 mg; about 185 mg; about 186 mg; about 187 mg; about 188 mg; about 189 mg; about 190 mg; about 191 mg; about 192 mg; about 193 mg; about 194 mg; about 195 mg; about 196 mg; about 197 mg; about 198 mg; about 199 mg; or about 200 mg. Recitation of each of these discrete values is understood to include ranges between each value. Recitation of each range is understood to include discrete values within the range. As described herein, the target material can be plated on a substrate or insulator having a plating area. The plating area can be about 20 mm2 or less. For example, the plating area can be between about 1 mm2 and about 40 mm2. As an example, the plating area can be about 1 mm2; about 2 mm2; about 3 mm2; about 4 mm2; about 5 mm2; about 6 mm2; about 7 mm2; about 8 mm2; about 9 mm2; about 10 mm2; about 11 mm2; about 12 mm2; about 13 mm2; about 14 mm2; about 15 mm2; about 16 mm2; about 17 mm2; about 18 mm2; about 19 mm2; about 20 mm2; about 21 mm2; about 22 mm2; about 23 mm2; about 24 mm2; about 25 mm2; about 26 mm2; about 27 mm2; about 28 mm2; about 29 mm2; about 30 mm2; about 31 mm2; about 32 mm2; about 33 mm2; about 34 mm2; about 35 mm2; about 36 mm2; about 37 mm2; about 38 mm2; about 39 mm2; or about 40 mm2. Recitation of each of these discrete values is understood to include ranges between each value. Recitation of each range is understood to include discrete values within the range. As described herein, the plating or substrate diameter can be about 5 mm or less. For example, the plating or substrate diameter can be between about 0.1 mm and about 10 mm. As an example, the plating or substrate diameter can be about 0.1 mm; 0.2 mm; about 0.3 mm; about 0.4 mm; about 0.5 mm; about 0.6 mm; about 0.7 mm, about 0.8 mm, about 0.9 mm; about 1 mm; about 1.1 mm; about 1.2 mm; about 1.3 mm; about 1.4 mm; about 1.5 mm; about 1.6 mm; about 1.7 mm, about 1.8 mm, about 1.9 mm, about 2 mm; about 2.1 mm; about 2.2 mm; about 2.3 mm; about 2.4 mm; about 2.5 mm; about 2.6 mm; about 2.7 mm; about 2.8 mm; about 2.9 mm; about 3 mm; about 3.1 mm; about 3.2 mm; about 3.3 mm; about 3.4 mm; about 3.5 mm; about 3.6 mm; about 3.7 mm; about 3.8 mm; about 3.9 mm; about 4 mm; about 4.1 mm; about 4.2 mm; about 4.3 mm; about 4.4 mm; about 4.5 mm; about 4.6 mm; about 4.7 mm; about 4.8 mm; about 4.9 mm; about 5 mm; about 5.1 mm; about 5.2 mm; about 5.3 mm; about 5.4 mm; about 5.5 mm; about 5.6 mm; about 5.7 mm; about 5.8 mm; about 5.9 mm; about 6 mm; about 6.1 mm; about 6.2 mm; about 6.3 mm; about 6.4 mm; about 6.5 mm; about 6.6 mm; about 6.7 mm; about 6.8 mm; about 6.9 mm; about 7 mm; about 7.1 mm; about 7.2 mm; about 7.3 mm; about 7.4 mm; about 7.5 mm; about 7.6 mm; about 7.7 mm; about 7.8 mm; about 7.9 mm; about 8 mm; about 8.1 mm; about 8.2 mm; about 8.3 mm; about 8.4 mm; about 8.5 mm; about 8.6 mm; about 8.7 mm; about 8.8 mm; about 8.9 mm; about 9 mm; about 9.1 mm; about 9.2 mm; about 9.3 mm; about 9.4 mm; about 9.5 mm; about 9.6 mm; about 9.7 mm; about 9.8 mm; about 9.9 mm; or about 10 mm. Recitation of each of these discrete values is understood to include ranges between each value. Recitation of each range is understood to include discrete values within the range. As described herein, the method provides for a thicker target and a reduction in target material. Compared to conventional methods, the plating area for the target material can be reduced by 20% and the target thickness can be increased by about 25%. This reduces the amount of material needed to produce a thick target material. The target material can have a thickness between about 1 μm and about 2,000 μm (2 mm). For example, the target material can have a thickness of about 1 μm; about 10 μm; about 20 μm; about 30 μm; about 40 μm; about 50 μm; about 60 μm; about 70 μm; about 80 μm; about 90 μm; about 100 μm; about 110 μm; about 120 μm; about 130 μm; about 140 μm; about 150 μm; about 160 μm; about 170 μm; about 180 μm; about 190 μm; about 200 μm; about 210 μm; about 220 μm; about 230 μm; about 240 μm; about 250 μm; about 260 μm; about 270 μm; about 280 μm; about 290 μm; about 300 μm; about 310 μm; about 320 μm; about 330 μm; about 340 μm; about 350 μm; about 360 μm; about 370 μm; about 380 μm; about 390 μm; about 400 μm; about 410 μm; about 420 μm; about 430 μm; about 440 μm; about 450 μm; about 460 μm; about 470 μm; about 480 μm; about 490 μm; about 500 μm; about 510 μm; about 520 μm; about 530 μm; about 540 μm; about 550 μm; about 560 μm; about 570 μm; about 580 μm; about 590 μm; about 600 μm; about 610 μm; about 620 μm; about 630 μm; about 640 μm; about 650 μm; about 660 μm; about 670 μm; about 680 μm; about 690 μm; about 700 μm; about 710 μm; about 720 μm; about 730 μm; about 740 μm; about 750 μm; about 760 μm; about 770 μm; about 780 μm; about 790 μm; about 800 μm; about 810 μm; about 820 μm; about 830 μm; about 840 μm; about 850 μm; about 860 μm; about 870 μm; about 880 μm; about 890 μm; about 900 μm; about 910 μm; about 920 μm; about 930 μm; about 940 μm; about 950 μm; about 960 μm; about 970 μm; about 980 μm; about 990 μm; about 1000 μm; about 1010 μm; about 1020 μm; about 1030 μm; about 1040 μm; about 1050 μm; about 1060 μm; about 1070 μm; about 1080 μm; about 1090 μm; about 1100 μm; about 1110 μm; about 1120 μm; about 1130 μm; about 1140 μm; about 1150 μm; about 1160 μm; about 1170 μm; about 1180 μm; about 1190 μm; about 1200 μm; about 1210 μm; about 1220 μm; about 1230 μm; about 1240 μm; about 1250 μm; about 1260 μm; about 1270 μm; about 1280 μm; about 1290 μm; about 1300 μm; about 1310 μm; about 1320 μm; about 1330 μm; about 1340 μm; about 1350 μm; about 1360 μm; about 1370 μm; about 1380 μm; about 1390 μm; about 1400 μm; about 1410 μm; about 1420 μm; about 1430 μm; about 1440 μm; about 1450 μm; about 1460 μm; about 1470 μm; about 1480 μm; about 1490 μm; about 1500 μm; about 1510 μm; about 1520 μm; about 1530 μm; about 1540 μm; about 1550 μm; about 1560 μm; about 1570 μm; about 1580 μm; about 1590 μm; about 1600 μm; about 1610 μm; about 1620 μm; about 1630 μm; about 1640 μm; about 1650 μm; about 1660 μm; about 1670 μm; about 1680 μm; about 1690 μm; about 1700 μm; about 1710 μm; about 1720 μm; about 1730 μm; about 1740 μm; about 1750 μm; about 1760 μm; about 1770 μm; about 1780 μm; about 1790 μm; about 1800 μm; about 1810 μm; about 1820 μm; about 1830 μm; about 1840 μm; about 1850 μm; about 1860 μm; about 1870 μm; about 1880 μm; about 1890 μm; about 1900 μm; about 1910 μm; about 1920 μm; about 1930 μm; about 1940 μm; about 1950 μm; about 1960 μm; about 1970 μm; about 1980 μm; about 1990 μm; or about 20000 μm. Recitation of each of these discrete values is understood to include ranges between each value. Recitation of each range is understood to include discrete values within the range. Isolation and Recovery of Radioisotopes of Copper Radioactive 60Cu, 61Cu, and 64Cu can be isolated and recovered as purified products of this discovery for further use in a radiolabel tracer compound. Each of the respective copper radionuclides (60, 61, and 64) can be produced from a different but respective enriched Ni target material for example: 60Cu is produced from 60Ni via the nuclear reaction 60Ni(p,n)60Cu, 61 Cu is produced from 61 Ni via the nuclear reaction 61Ni(p,n)61Cu and 64Cu is produced from 64Ni via the nuclear reaction 64Ni(p,n)64Cu. In some embodiments, 61Cu is also produced by the 62Ni[d,n]61Cu nuclear reaction. In some embodiments, the system can comprise two stand alone unit(s) in an automated system which can be operated together. In an embodiment, a first stand alone unit can be a functional automated copper radionuclide separation and purification process. In another embodiment, a second stand alone unit can be a functional automated copper radionuclide labeling process. In another embodiment, radioactive 60Cu, 61Cu, or 64Cu can be isolated and recovered as purified products of this discovery for further use in a radiolabel tracer compound. In another embodiment, the automated system can be electrically/pneumatically/communicatively configured, capable and functional in all operationally necessary embodiments. The process for enhancing the specific activity, yield, and purity can comprise processes for separating, purifying, and recovering radionuclides from a multi-component composition and labeling individual radionuclides. In some embodiments, the disclosed method utilizes liquid chromatography to selectively separate Nickel-60 from a mixture of Copper-60 and Nickel-60; selectively separate Nickel-61 from a mixture of Copper-61 and Nickel-61; or to selectively separate Nickel-64 from a mixture of Copper-64 and Nickel-64. Copper-64 can be useful in clinical, major medical treatment, and/or research facilities as it can be distributed to multiple sites and as a radionuclide for pharmaceutical. The term “chromatography” can include techniques involving mass-transfer between one or more stationary phases and one or more mobile phases such as typically carried out in a chromatographic separation zone. The term “chromatography” can include any useful form that uses a column or tube or container having an internal lumen to satisfactorily hold a stationary phase. Useful illustrative chromatographic techniques include open column chromatography, HPLC, or open tubular capillary chromatography. In some embodiments, Liquid Chromatography (LC) can be utilized as a mode of chromatography on a multi component feed composition containing a precursor nuclide of nickel and a nickel bombardment product being a radionuclide of copper. In separating radionuclides, LC utilizes a liquid mobile phase to successfully effectively separate the components of a mixture, such as a mixture of Copper-64 and Nickel-64. The Nickel-64 and Copper-64 components (or analytes) (or Nickel-60 in Copper-60 or Nickel 61 in Copper-61) can be dissolved in a solvent, and fed to a chromatographic column under atmospheric pressure or gravity. In the column, the mixture is resolved into its components. In some embodiments, the stationary phase is immobile packing material in the column. In some embodiments, the immobile packing material is held in place by an appropriate packing support in the lumen of the column. In some embodiments, the immobile packing material can be purchased as a part of the column or added to the lumen of the chromatographic column prior to loading of the components to be separated. The pressure in the column is generally atmospheric pressure in the range from about 1 to about 2 atmospheres (14.7 to 29.4 psi respectively). In some embodiments, the column is a vented column and elution is by gravity. In some embodiments, the column can be pressurized up to about 2.5 atm (35 psi) without affecting its operability. In some embodiments, the extraction process can use the ionic affinity of Nickel-60 or -61 or -64 to a solvent employed as a liquid mobile phase carrier to selectively remove the Nickel-60 or -61 or -64 from a liquid composition containing Nickel-60 or -61 or -64 and Copper-60 or -61 or -64, wherein the composition is loaded on a packing in a separation zone and the mobile phase carrier is passed there through. In some embodiments, the term “stationary phase” refers to solid support such as packing including ion exchange resin contained within the lumen or interior of the chromatographic separation such as in a column over which or through which the mobile phase flows. The mobile phase may be continuous, semi-continuous, or batch. In some embodiments, the composition containing Nickel-60 or -61 or -64 in Copper-60 or -61 or -64 is typically a liquid and can be injected into the mobile phase (HCl) of the chromatographic column through a coupled injector leak tight port. As the composition to be refined/purified flows with the mobile phase through the stationary phase in the chromatographic separation zone of the column, the components of that composition to be refined migrate to the stationary phase. The main requisite for selection of a mobile phase herein is its capability to dissolve the composition containing the copper and nickel radionuclides at least up to a concentration suitable for the detection system coupled to the effluent of the column. This means that the column is selected to have the capability to provide the desired degree of refining/purification/extraction of the composition loaded onto the column so as to provide a refined Copper-60 or -61 or -64 radionuclide from a mixture of Copper-60 or -61 or -64 radionuclide and Nickel-60 or -61 or -64. This inventive process comprises admixing a portion of a multi-component composition to be refined (i.e., having a Nickel-64 component desired to be purified) with a first mobile phase carrier to form a chromatographically separable multi-component separable composition comprising a first mobile phase carrier. The first mobile phase carrier has a high affinity for the Nickel-64 which is the material to be separated from the Copper-64. The chromatographically separable composition can be passed into a chromatographic separation zone having as packing therein ion exchange resins having an average particle diameter in the range from about 100 microns to about 200 microns. An eluent is thereby formed of a component (Nickel-64) of the multi-component composition. In some embodiments, the eluent is removed from the column and passed through an appropriate detector for analysis In some embodiments, the temperature of the chromatographic column can be in the range from about ambient temperature to about 60° C. or about 70° C. The initial addition of mobile phase carrier can be at about 98° C. and subsequent additions can be at about room temperature (about 25° C.). In some embodiments, the eluent of the individual desired radionuclide (Copper-60, Copper-61, or Copper-64) is temporarily retained within the chromatographic system. A second mobile phase carrier having an affinity for the temporarily retained copper radionuclide is passed/loaded into the chromatographic separation zone following a first mobile phase carrier, thereby forming a purified eluent containing the component of interest in a purified or refined form. In some embodiments, the column is a HCl (hydrochloric acid) acid attack resistant plastic or glass construction or a suitable rounded container and has leak-proof secure fittings at the ends of the column that connects the column to the injector at the loading end of the column and a detector at the effluent end. In some embodiments, the column has suitable internal configuration to hold the packing. In some embodiments, the purified eluent comprising the purified copper radionuclide can be there after passed into a label process for appropriate labeling of the refined copper radionuclide with a ligand, if desired. In some embodiments, (aqueous) HCl can be employed as a first mobile phase carrier. In some embodiments, the concentration of the HCl employed as a first mobile phase carrier to remove nickel radionuclide from the column is in the range from about 5 to about 7 and preferably from about 5.5 to about 6.5 molar. 6 M HCl is prepared from concentrated 12 M, ultra-pure 99.999999%, copper-free HCl and 18 Meg-ohm water. HCl (hydrochloric acid) also known as muriatic acid and chlorohydric acid is available commercially as an aqueous concentrate at about 12 M. In some embodiments, (aqueous) HCl is employed as a second mobile phase carrier to remove the temporarily intentionally retained copper radionuclide from the column. The concentration of the HCl employed as a liquid, a second mobile phase carrier, is in the range from about 0.3 M to about 0.7 M and preferably from about 0.4 M to about 0.6 M. 0.5 M HCl is prepared from concentrated 12 M, ultra-pure 99.999999%, copper-free HCl and 18 Meg-ohm water. Essentially, the first mobile phase carrier can be a high molarity aqueous hydrochloric acid composition and the second mobile phase carrier can be a low molarity aqueous hydrochloric acid composition. In some embodiments, the second mobile phase carrier can be passed through the column after the passage of the first mobile phase carrier through the column. In some embodiments, both the first mobile phase carrier and second mobile phase carrier can be passed through the column in the same direction over column packing. Typical materials of construction of the first chromatographic separation zone include acid resistant plastic or glass such as plastics and glass resistant to chemical attack by 6 N HCl (and above) and acid fumes or any suitable rounded container having a lumen therein. In some embodiments, the removed eluent can be further processed for 60Ni, 61Ni, or 64Ni recovery recycling. In some embodiments, 60Cu, 61Cu, or 64Cu can be retained into the ion exchange column resin. The enriched nickel nuclide is eluted from the column and isolated for recycling purposes for the preparation on another target material. 60CU, 61Cu, or 64Cu is subsequently recovered by addition of about 0.5 N HCl to elute purified 60CU, 61 Cu, or 64Cu for recovery and subsequently for labeling. In one embodiment, the column can comprise a borosilicate (glass) Econo-column from Bio-Rad having catalog number 737-1031. Other sizes and material construction of columns can be employed for this application. In more detail the 737-1031 chromatographic column is 1.0×30 cm, 24 ml. About 4 cm of packing material is used in the column or 2.74 to 2.76 grams and preferably near 2.75 grams of packing material. Packing support which is understood to be a porous polymer bed support is manually packed in the column. In some embodiments, the column has translucent polypropylene end fittings (such as Luer-Lok) which allow visualization of the column bed. Another illustrative useful column is a jacketed Econo-Column which is another type of Econo-Column from Bio-Rad and which has an integral water jacket. The term “chromatographic separation zone” is employed herein to mean any zone capable of effecting a separation of the components of a multi-component composition and includes useful chromatographic zones such as chromatographic columns of any useful shape, size, description or composition. As used herein, the term “column” includes a plastic or glass high normality hydrochloric acid resistant tube or rounded container having a lumen therein with polished inner surface and fittings at both ends suitably configured for packing with small porous adsorbent particles as column packing therein. The term “packing” is employed throughout this application and includes any ion exchange resin or any suitable retaining material employed in the internal volume of a chromatographic separation zone which is capable of retaining thereon a component of interest (copper radionuclide) releasable from the packing upon elution with an appropriately selected mobile phase carrier. The term “multi-component composition” is employed throughout to mean a composition containing more than one component and includes compositions such as mixtures as well as true solutions. As used herein, the term “preparation, synthesis, purification and recovery” to such a state/condition ready for use such as use as a radionuclide with a tracer compound for diagnostic imaging in animals. In an embodiment, packing employed in a chromatographic separation zone in a first embodiment of this discovery has a particle size diameter in the range from about 30 to about 1000 microns and preferably from about 35 to about 400 microns. The type of packing as retention support material which may be employed in the chromatographic separation zone and any second chromatographic separation zone is selected to retain a component of interest within a discreet zone of the packing which is releasable upon sequential elution with an appropriately selected mobile phase carrier after reading this specification. In some embodiments, the packing is selected to temporarily retain Copper-60, Copper-61, or Copper-64, which is sequentially and selectively releasable from such temporary retention by passing an appropriate mobile phase carrier over the packing containing the Copper-60, Copper-61, or Copper-64. Typical useful non-limiting packing includes polystyrene, divinyl benzene resin, or silica base packing. In an embodiment, packing employed comprises Bio-Rad AGO 1-X8 Resin, 100-200 mesh chloride from catalog 140-1441, Bio-Rad Laboratories, 2000 Alfred Nobel Drive, Hercules, Calif. 84547. The resin is a styrene type-quaternary ammonium having a medium effective pore size with a Total Capacity of 2.6 meq/dry g, 1.2 meq/ml resin bed, Actual Wet Mesh Range of 80-140 (US Std) 106-180 microns, Moisture content of 39-48% by wt. and density (nominal) 0.75 gm/ml. The term “mobile phase carrier” is employed throughout this application to include any composition capable of being passed into a chromatographic separation zone to effect the elution of a compound temporarily retained in the packing of a chromatographic separation zone. Typically the mobile phase carrier is a liquid or in liquid form at the time of being passed. In some embodiments, the particular mobile phase carrier associated with first chromatographic separation zone corresponds with the type of packing employed in a first chromatographic separation zone. Copper Radioisotopes Described herein are methods and systems for producing Cu radioisotopes with increased yield, purity, and specific activity. As used herein, the term “detectably labeled” includes respective highly purified 60Cu, 61Cu, or 64Cu labeled compounds having an effective amount of an emitting copper radionuclide radiolabel therewith suitably accommodating for use in effective administration/therapy to living mammals. The longer half-life (t1/2) of the copper radioisotopes allows for regional or national production. A radionuclide can also be referred to as a radioactive nuclide, radioisotope, or radioactive isotope. Imaging Agent As described herein, the copper radionuclides can be used as an imaging agent in humans and animals. In some embodiments, small animal imaging using copper radionuclides (60Cu, 61Cu and 64Cu) can be performed on rodents (including mice and rats) following administration thereto of copper radiopharmaceuticals. As used herein, the term “small animal” imaging includes imaging performed on cats, dogs, mice, rats and rodents. As used herein the term “rodent” includes members of the Order of Rodentia including squirrels, rats, prairie dogs, porcupines, mice, lemmings, marmots, guinea pigs, hamsters, gophers, gerbils, chipmunks, chinchillas, beaver, capybaras, porcupines, ground squirrels, or beaver. Safety In some embodiments, from a safety perspective, the process is monitored by using a suitable radiation detector and alerting system behind the column to monitor the activity displacement from the dissolution used to the recovery unit configured for, adapted to and affixed to the effluent process connection of the separation column. Formulation As described herein, the copper radionuclides can be formulated for use as an imaging agent or a therapeutic agent. For example, the copper radionuclides can be used as a PET imaging agent. As another example, the copper radionuclides can be used as a radiotherapeutic agent or radiopharmaceutical. Conventionally, the term “purified 64Cu” has a—specific activity—in the range from about 20 mCi/μg to about 200 mCi/μg and preferably at least about 20 mCi/μg for use as an imaging agent and a higher specific activity ranging from about 150 mCi/μg to about 200 mCi/μg for use as a therapeutic agent. As described herein, the disclosed improved process provides for a “purified 64Cu” having a specific activity in the range from at least about 200 mCi/μg to at least about 250 mCi/μg for use as an imaging agent or a therapeutic agent. For example, the 64Cu made according to the present disclosure can have a specific activity of about mCi/μg; about 13 mCi/μg; about 14 mCi/μg; about 15 mCi/μg; about 16 mCi/μg; about 17 mCi/μg; about 18 mCi/μg; about 19 mCi/μg; about 20 mCi/μg; about 21 mCi/μg; about 22 mCi/μg; about 23 mCi/μg; about 24 mCi/μg; about 25 mCi/μg; about 26 mCi/μg; about 27 mCi/μg; about 28 mCi/μg; about 29 mCi/μg; about 30 mCi/μg; about 31 mCi/μg; about 32 mCi/μg; about 33 mCi/μg; about 34 mCi/μg; about 35 mCi/μg; about 36 mCi/μg; about 37 mCi/μg; about 38 mCi/μg; about 39 mCi/μg; about 40 mCi/μg; about 41 mCi/μg; about 42 mCi/μg; about 43 mCi/μg; about 44 mCi/μg; about 45 mCi/μg; about 46 mCi/μg; about 47 mCi/μg; about 48 mCi/μg; about 49 mCi/μg; about 50 mCi/μg; about 51 mCi/μg; about 52 mCi/μg; about 53 mCi/μg; about 54 mCi/μg; about 55 mCi/μg; about 56 mCi/μg; about 57 mCi/μg; about 58 mCi/μg; about 59 mCi/μg; about 60 mCi/μg; about 61 mCi/μg; about 62 mCi/μg; about 63 mCi/μg; about 64 mCi/μg; about 65 mCi/μg; about 66 mCi/μg; about 67 mCi/μg; about 68 mCi/μg; about 69 mCi/μg; about 70 mCi/μg; about 71 mCi/μg; about 72 mCi/μg; about 73 mCi/μg; about 74 mCi/μg; about 75 mCi/μg; about 76 mCi/μg; about 77 mCi/μg; about 78 mCi/μg; about 79 mCi/μg; about 80 mCi/μg; about 81 mCi/μg; about 82 mCi/μg; about 83 mCi/μg; about 84 mCi/μg; about 85 mCi/μg; about 86 mCi/μg; about 87 mCi/μg; about 88 mCi/μg; about 89 mCi/μg; about 90 mCi/μg; about 91 mCi/μg; about 92 mCi/μg; about 93 mCi/μg; about 94 mCi/μg; about 95 mCi/μg; about 96 mCi/μg; about 97 mCi/μg; about 98 mCi/μg; about 99 mCi/μg; about 100 mCi/μg; about 101 mCi/μg; about 102 mCi/μg; about 103 mCi/μg; about 104 mCi/μg; about 105 mCi/μg; about 106 mCi/μg; about 107 mCi/μg; about 108 mCi/μg; about 109 mCi/μg; about 110 mCi/μg; about 111 mCi/μg; about 112 mCi/μg; about 113 mCi/μg; about 114 mCi/μg; about 115 mCi/μg; about 116 mCi/μg; about 117 mCi/μg; about 118 mCi/μg; about 119 mCi/μg; about 120 mCi/μg; about 121 mCi/μg; about 122 mCi/μg; about 123 mCi/μg; about 124 mCi/μg; about 125 mCi/μg; about 126 mCi/μg; about 127 mCi/μg; about 128 mCi/μg; about 129 mCi/μg; about 130 mCi/μg; about 131 mCi/μg; about 132 mCi/μg; about 133 mCi/μg; about 134 mCi/μg; about 135 mCi/μg; about 136 mCi/μg; about 137 mCi/μg; about 138 mCi/μg; about 139 mCi/μg; about 140 mCi/μg; about 141 mCi/μg; about 142 mCi/μg; about 143 mCi/μg; about 144 mCi/μg; about 145 mCi/μg; about 146 mCi/μg; about 147 mCi/μg; about 148 mCi/μg; about 149 mCi/μg; about 150 mCi/μg; about 151 mCi/μg; about 152 mCi/μg; about 153 mCi/μg; about 154 mCi/μg; about 155 mCi/μg; about 156 mCi/μg; about 157 mCi/μg; about 158 mCi/μg; about 159 mCi/μg; about 160 mCi/μg; about 161 mCi/μg; about 162 mCi/μg; about 163 mCi/μg; about 164 mCi/μg; about 165 mCi/μg; about 166 mCi/μg; about 167 mCi/μg; about 168 mCi/μg; about 169 mCi/μg; about 170 mCi/μg; about 171 mCi/μg; about 172 mCi/μg; about 173 mCi/μg; about 174 mCi/μg; about 175 mCi/μg; about 176 mCi/μg; about 177 mCi/μg; about 178 mCi/μg; about 179 mCi/μg; about 180 mCi/μg; about 181 mCi/μg; about 182 mCi/μg; about 183 mCi/μg; about 184 mCi/μg; about 185 mCi/μg; about 186 mCi/μg; about 187 mCi/μg; about 188 mCi/μg; about 189 mCi/μg; about 190 mCi/μg; about 191 mCi/μg; about 192 mCi/μg; about 193 mCi/μg; about 194 mCi/μg; about 195 mCi/μg; about 196 mCi/μg; about 197 mCi/μg; about 198 mCi/μg; about 199 mCi/μg; about 200 mCi/μg; about 201 mCi/μg; about 202 mCi/μg; about 203 mCi/μg; about 204 mCi/μg; about 205 mCi/μg; about 206 mCi/μg; about 207 mCi/μg; about 208 mCi/μg; about 209 mCi/μg; about 210 mCi/μg; about 211 mCi/μg; about 212 mCi/μg; about 213 mCi/μg; about 214 mCi/μg; about 215 mCi/μg; about 216 mCi/μg; about 217 mCi/μg; about 218 mCi/μg; about 219 mCi/μg; about 220 mCi/μg; about 221 mCi/μg; about 222 mCi/μg; about 223 mCi/μg; about 224 mCi/μg; about 225 mCi/μg; about 226 mCi/μg; about 227 mCi/μg; about 228 mCi/μg; about 229 mCi/μg; about 230 mCi/μg; about 231 mCi/μg; about 232 mCi/μg; about 233 mCi/μg; about 234 mCi/μg; about 235 mCi/μg; about 236 mCi/μg; about 237 mCi/μg; about 238 mCi/μg; about 239 mCi/μg; about 240 mCi/μg; about 241 mCi/μg; about 242 mCi/μg; about 243 mCi/μg; about 244 mCi/μg; about 245 mCi/μg; about 246 mCi/μg; about 247 mCi/μg; about 248 mCi/μg; about 249 mCi/μg; or about 250 mCi/μg. Recitation of each of these discrete values is understood to include ranges between each value. Recitation of each range is understood to include discrete values within the range. As used herein, the expression “pharmaceutically acceptable” can apply to a composition comprising a compound or its copper radiolabeled counterpart herein, which contains composition ingredients that can be compatible with other ingredients of the composition as well as physiologically acceptable to the recipient, e.g., a mammal such as a human. In an embodiment, a composition can comprise one or more carriers, useful excipients and/or diluents. In some embodiments, the composition comprises at least one of a 60Cu, 61 Cu, or 64Cu detectably labeled compound. A pharmaceutical composition can comprise a (purified, if desired) tracer compound with an emitting radiolabel such as a copper nuclide and optionally a suitable adjuvant such as a surfactant which is pharmacologically acceptable to the patient such as to a living mammal such as a living human. The pharmaceutical can comprise a water soluble salt of a tracer compound in an aqueous with an associated emitting radiolabel as well as a saline solution. High purity radiolabel and high activity radiolabel are preferred. The choice of tracer compound and radiolabel will be determined to an extent by the particular affliction being diagnosed, such as cancer. The agents and compositions described herein can be formulated by any conventional manner using one or more pharmaceutically acceptable carriers or excipients as described in, for example, Remington's Pharmaceutical Sciences (A. R. Gennaro, Ed.), 21st edition, ISBN: 0781746736 (2005), incorporated herein by reference in its entirety. Such formulations will contain a therapeutically effective amount of a biologically active agent described herein, which can be in purified form, together with a suitable amount of carrier so as to provide the form for proper administration to the subject. In some embodiments, as used herein the term “patient” includes a human and a non-human such as feline, canine, horse and murine. The term “formulation” refers to preparing a drug in a form suitable for administration to a subject, such as a human. Thus, a “formulation” can include pharmaceutically acceptable excipients, including diluents or carriers. The term “pharmaceutically acceptable” as used herein can describe substances or components that do not cause unacceptable losses of pharmacological activity or unacceptable adverse side effects. Examples of pharmaceutically acceptable ingredients can be those having monographs in United States Pharmacopeia (USP 29) and National Formulary (NF 24), United States Pharmacopeial Convention, Inc, Rockville, Md., 2005 (“USP/NF”), or a more recent edition, and the components listed in the continuously updated Inactive Ingredient Search online database of the FDA. Other useful components that are not described in the USP/NF, etc. may also be used. The term “pharmaceutically acceptable excipient,” as used herein, can include any and all solvents, dispersion media, coatings, antibacterial and antifungal agents, isotonic, or absorption delaying agents. The use of such media and agents for pharmaceutical active substances is well known in the art (see generally Remington's Pharmaceutical Sciences (A. R. Gennaro, Ed.), 21st edition, ISBN: 0781746736 (2005)). Except insofar as any conventional media or agent is incompatible with an active ingredient, its use in the therapeutic compositions is contemplated. Supplementary active ingredients can also be incorporated into the compositions. A “stable” formulation or composition can refer to a composition having sufficient stability to allow storage at a convenient temperature, such as between about 0° C. and about 60° C., for a commercially reasonable period of time, such as at least about one day, at least about one week, at least about one month, at least about three months, at least about six months, at least about one year, or at least about two years. The formulation should suit the mode of administration. The agents of use with the current disclosure can be formulated by known methods for administration to a subject using several routes which include, but are not limited to, parenteral, pulmonary, oral, topical, intradermal, intramuscular, intraperitoneal, intravenous, subcutaneous, intranasal, epidural, ophthalmic, buccal, and rectal. The individual agents may also be administered in combination with one or more additional agents or together with other biologically active or biologically inert agents. Such biologically active or inert agents may be in fluid or mechanical communication with the agent(s) or attached to the agent(s) by ionic, covalent, Van der Waals, hydrophobic, hydrophilic or other physical forces. Controlled-release (or sustained-release) preparations may be formulated to extend the activity of the agent(s) and reduce dosage frequency. Controlled-release preparations can also be used to effect the time of onset of action or other characteristics, such as blood levels of the agent, and consequently affect the occurrence of side effects. Controlled-release preparations may be designed to initially release an amount of an agent(s) that produces the desired therapeutic effect, and gradually and continually release other amounts of the agent to maintain the level of therapeutic effect over an extended period of time. In order to maintain a near-constant level of an agent in the body, the agent can be released from the dosage form at a rate that will replace the amount of agent being metabolized or excreted from the body. The controlled-release of an agent may be stimulated by various inducers, e.g., change in pH, change in temperature, enzymes, water, or other physiological conditions or molecules. Agents or compositions described herein can also be used in combination with other therapeutic modalities, as described further below. Thus, in addition to the therapies described herein, one may also provide to the subject other therapies known to be efficacious for treatment of the disease, disorder, or condition. Therapeutic Methods Also provided is a process of treating cancer in a subject in need administration of a therapeutically effective amount of a radiopharmaceutical comprising a copper radioisotope, so as to increase the survival time of tumor-bearing subjects or reduce tumor burden. Recently there has been a renewed interest in Cu-64 as a therapeutic due to its relatively long half-life. For example, F-18 half-life is not long enough to bind to some receptors. Methods described herein are generally performed on a subject in need thereof. A subject in need of the therapeutic methods described herein can be a subject having, diagnosed with, suspected of having, or at risk for developing cancer. A determination of the need for treatment will typically be assessed by a history and physical exam consistent with the disease or condition at issue. Diagnosis of the various conditions treatable by the methods described herein is within the skill of the art. The subject can be an animal subject, including a mammal, such as horses, cows, dogs, cats, sheep, pigs, mice, rats, monkeys, hamsters, guinea pigs, and chickens, and humans. For example, the subject can be a human subject. Generally, a safe and effective amount of a radiopharmaceutical agent is, for example, that amount that would cause the desired therapeutic effect in a subject while minimizing undesired side effects. In various embodiments, an effective amount of a radiopharmaceutical agent described herein can substantially inhibit the growth of cancer, slow the progress of cancer, or limit the development of cancer. According to the methods described herein, administration can be parenteral, pulmonary, oral, topical, intradermal, intramuscular, intraperitoneal, intravenous, subcutaneous, intranasal, epidural, ophthalmic, buccal, or rectal administration. When used in the treatments described herein, a therapeutically effective amount of a radiopharmaceutical agent can be employed in pure form or, where such forms exist, in pharmaceutically acceptable salt form and with or without a pharmaceutically acceptable excipient. For example, the compounds of the present disclosure can be administered, at a reasonable benefit/risk ratio applicable to any medical treatment, in a sufficient amount to increase the survival time of tumor-bearing subjects, reduce tumor burden, substantially inhibit the growth of cancer, slow the progress of cancer, or limit the development of cancer. The amount of a composition described herein that can be combined with a pharmaceutically acceptable carrier to produce a single dosage form will vary depending upon the host treated and the particular mode of administration. It will be appreciated by those skilled in the art that the unit content of agent contained in an individual dose of each dosage form need not in itself constitute a therapeutically effective amount, as the necessary therapeutically effective amount could be reached by administration of a number of individual doses. Toxicity and therapeutic efficacy of compositions described herein can be determined by standard pharmaceutical procedures in cell cultures or experimental animals for determining the LD50 (the dose lethal to 50% of the population) and the ED50, (the dose therapeutically effective in 50% of the population). The dose ratio between toxic and therapeutic effects is the therapeutic index that can be expressed as the ratio LD50/ED50, where larger therapeutic indices are generally understood in the art to be optimal. The specific therapeutically effective dose level for any particular subject will depend upon a variety of factors including the disorder being treated and the severity of the disorder; activity of the specific compound employed; the specific composition employed; the age, body weight, general health, sex and diet of the subject; the time of administration; the route of administration; the rate of excretion of the composition employed; the duration of the treatment; drugs used in combination or coincidental with the specific compound employed; and like factors well known in the medical arts (see e.g., Koda-Kimble et al. (2004) Applied Therapeutics: The Clinical Use of Drugs, Lippincott Williams & Wilkins, ISBN 0781748453; Winter (2003) Basic Clinical Pharmacokinetics, 4th ed., Lippincott Williams & Wilkins, ISBN 0781741475; Shamel (2004) Applied Biopharmaceutics & Pharmacokinetics, McGraw-Hill/Appleton & Lange, ISBN 0071375503). For example, it is well within the skill of the art to start doses of the composition at levels lower than those required to achieve the desired therapeutic effect and to gradually increase the dosage until the desired effect is achieved. If desired, the effective daily dose may be divided into multiple doses for purposes of administration. Consequently, single dose compositions may contain such amounts or submultiples thereof to make up the daily dose. It will be understood, however, that the total daily usage of the compounds and compositions of the present disclosure will be decided by an attending physician within the scope of sound medical judgment. Again, each of the states, diseases, disorders, and conditions, described herein, as well as others, can benefit from compositions and methods described herein. Generally, treating a state, disease, disorder, or condition includes preventing or delaying the appearance of clinical symptoms in a mammal that may be afflicted with or predisposed to the state, disease, disorder, or condition but does not yet experience or display clinical or subclinical symptoms thereof. Treating can also include inhibiting the state, disease, disorder, or condition, e.g., arresting or reducing the development of the disease or at least one clinical or subclinical symptom thereof. Furthermore, treating can include relieving the disease, e.g., causing regression of the state, disease, disorder, or condition or at least one of its clinical or subclinical symptoms. A benefit to a subject to be treated can be either statistically significant or at least perceptible to the subject or to a physician. Administration of a radiopharmaceutical agent can occur as a single event or over a time course of treatment. For example, a radiopharmaceutical agent can be administered daily, weekly, bi-weekly, or monthly. For treatment of acute conditions, the time course of treatment will usually be at least several days. Certain conditions could extend treatment from several days to several weeks. For example, treatment could extend over one week, two weeks, or three weeks. For more chronic conditions, treatment could extend from several weeks to several months or even a year or more. Treatment in accord with the methods described herein can be performed prior to, concurrent with, or after conventional treatment modalities for cancer. Administration As used herein, the term “administration” can include the successful administration of an individually highly purified 60Cu, 61Cu, or 64Cu labeled compound by any useful means to a living mammal and its successful introduction into the mammal internally such as by intravenous injection in an effective method which results in that compound, its salt, its ions, metabolites or derivatives being made biologically available to that mammal receiving administration of the highly purified 60Cu, 61Cu and 64Cu labeled compound for medicinal or therapeutic use. In some embodiments, the mammal is a living nonhuman mammal such as a canine, feline, rat, rodent, mouse or a living cell therefrom. In an embodiment, the highly purified 60Cu, 61Cu, or 64Cu labeled compound can be made biologically available to the mammal patient. In some embodiments, the administration comprises giving of at least one of a highly purified 60Cu, 61Cu, or 64Cu detectably labeled compound. In some embodiments, the mammal is a human and the radionuclide is individually Copper-60 or Copper-61, or Copper-64. As used herein, the term “dosage” can include that amount of automatically separated, recovered and purified 60Cu, 61Cu, or 64Cu compound which when effectively administered to a living mammal provides an effective amount of biologically available 60Cu, 61Cu, or 64Cu labeled compound to the living mammal to enable radioimage detection and acquisition via external radioimage detector or to enable a therapeutically effective response (e.g., reduction in tumor size, reduction in cancer cells, reduction in tumor/cancer burden). In some embodiments, the term “tissue” includes mammalian body tissue of the mammal being administered the radiolabeled compound. Agents and compositions described herein can be administered according to methods described herein in a variety of means known to the art. As discussed above, administration can be parenteral, pulmonary, oral, topical, intradermal, intramuscular, intraperitoneal, intravenous, subcutaneous, intranasal, epidural, ophthalmic, buccal, or rectal administration. Agents and compositions described herein can be administered in a variety of methods well known in the arts. Administration can include, for example, methods involving oral ingestion, direct injection (e.g., systemic or stereotactic), implantation of cells engineered to secrete the factor of interest, drug-releasing biomaterials, polymer matrices, gels, permeable membranes, osmotic systems, multilayer coatings, microparticles, implantable matrix devices, mini-osmotic pumps, implantable pumps, injectable gels and hydrogels, liposomes, micelles (e.g., up to 30 μm), nanospheres (e.g., less than 1 μm), microspheres (e.g., 1 μm-100 μm), reservoir devices, a combination of any of the above, or other suitable delivery vehicles to provide the desired release profile in varying proportions. Other methods of controlled-release delivery of agents or compositions will be known to the skilled artisan and are within the scope of the present disclosure. Delivery systems may include, for example, an infusion pump which may be used to administer the agent or composition in a manner similar to that used for delivering insulin or chemotherapy to specific organs or tumors. Typically, using such a system, an agent or composition can be administered in combination with a biodegradable, biocompatible polymeric implant that releases the agent over a controlled period of time at a selected site. Examples of polymeric materials include polyanhydrides, polyorthoesters, polyglycolic acid, polylactic acid, polyethylene vinyl acetate, and copolymers and combinations thereof. In addition, a controlled release system can be placed in proximity of a therapeutic target, thus requiring only a fraction of a systemic dosage. Agents can be encapsulated and administered in a variety of carrier delivery systems. Examples of carrier delivery systems include microspheres, hydrogels, polymeric implants, smart polymeric carriers, and liposomes (see generally, Uchegbu and Schatzlein, eds. (2006) Polymers in Drug Delivery, CRC, ISBN-10: 0849325331). Carrier-based systems for molecular or biomolecular agent delivery can: provide for intracellular delivery; tailor biomolecule/agent release rates; increase the proportion of biomolecule that reaches its site of action; improve the transport of the drug to its site of action; allow colocalized deposition with other agents or excipients; improve the stability of the agent in vivo; prolong the residence time of the agent at its site of action by reducing clearance; decrease the nonspecific delivery of the agent to nontarget tissues; decrease irritation caused by the agent; decrease toxicity due to high initial doses of the agent; alter the immunogenicity of the agent; decrease dosage frequency, improve taste of the product; or improve shelf life of the product. Definitions and methods described herein are provided to better define the present disclosure and to guide those of ordinary skill in the art in the practice of the present disclosure. Unless otherwise noted, terms are to be understood according to conventional usage by those of ordinary skill in the relevant art. In some embodiments, numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth, used to describe and claim certain embodiments of the present disclosure are to be understood as being modified in some instances by the term “about.” In some embodiments, the term “about” is used to indicate that a value includes the standard deviation of the mean for the device or method being employed to determine the value. In some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the present disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the present disclosure may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements. The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. In some embodiments, the terms “a” and “an” and “the” and similar references used in the context of describing a particular embodiment (especially in the context of certain of the following claims) can be construed to cover both the singular and the plural, unless specifically noted otherwise. In some embodiments, the term “or” as used herein, including the claims, is used to mean “and/or” unless explicitly indicated to refer to alternatives only or the alternatives are mutually exclusive. The terms “comprise,” “have” and “include” are open-ended linking verbs. Any forms or tenses of one or more of these verbs, such as “comprises,” “comprising,” “has,” “having,” “includes” and “including,” are also open-ended. For example, any method that “comprises,” “has” or “includes” one or more steps is not limited to possessing only those one or more steps and can also cover other unlisted steps. Similarly, any composition or device that “comprises,” “has” or “includes” one or more features is not limited to possessing only those one or more features and can cover other unlisted features. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the present disclosure and does not pose a limitation on the scope of the present disclosure otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the present disclosure. Groupings of alternative elements or embodiments of the present disclosure disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims. All publications, patents, patent applications, and other references cited in this application are incorporated herein by reference in their entirety for all purposes to the same extent as if each individual publication, patent, patent application or other reference was specifically and individually indicated to be incorporated by reference in its entirety for all purposes. Citation of a reference herein shall not be construed as an admission that such is prior art to the present disclosure. Having described the present disclosure in detail, it will be apparent that modifications, variations, and equivalent embodiments are possible without departing the scope of the present disclosure defined in the appended claims. Furthermore, it should be appreciated that all examples in the present disclosure are provided as non-limiting examples. The following non-limiting examples are provided to further illustrate the present disclosure. It should be appreciated by those of skill in the art that the techniques disclosed in the examples that follow represent approaches the inventors have found function well in the practice of the present disclosure, and thus can be considered to constitute examples of modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments that are disclosed and still obtain a like or similar result without departing from the spirit and scope of the present disclosure. The manufacturing process of Cu-64 with high yield, specific activity, and purity, includes the target preparation by electroplating, bombardment with a proton beam having an energy of 14.25 MeV, and a specialized processing system developed at Washington University to produce Cu-64 chloride and recovery of the enriched Ni-64. Parameters Electroplating—the goal in this example was to achieve a thick target. Here, the disclosed process uses less than 80 mg of enriched Ni-64 to achieve a thick target. To accomplish this, the target material plating area was limited to 20 mm2. The plating area restriction typically requires modification to the proton beam shape of the cyclotron used to produce Cu-64 by focusing and constraining the proton beam prior to striking the target material. Reduction of the size of the plating area, (see e.g., FIG. 3), for example, using Ni-64 as the target can be accomplished by reducing the plating area by 20%, and increasing the target thickness by 25%, thus reducing the amount of Ni-64 needed to produce a thick target. Reducing the amount of Ni-64 will significantly reduce cost and continue to improve specific activity. Improving the yield to material usage is established by reducing area, thus increasing the thickness of the target. To accomplish this, the target material was limited to a plating area 20 mm2. The plating area restriction required modification to the proton beam shape of the cyclotron used to produce Cu-64 by constraining the proton beam prior to striking the target material. Reducing the plating area improved the process. The disclosed design focuses on shaping the plating area to match the beam spot. To accomplish this, target holders were slightly redesigned to insure the orientation of the plated Ni-64. Other plating parameters metals and chemicals used and power inputs are well defined. Metals are nickel-plated routinely for appearance. Visual Analysis of Ni-64 Target Prior to Bombardment Microscopic analysis of the electroplated Ni-64 target material has eliminated unexpected vaporized target and aids in predicting target saturation yields based on irregularities in the plating surface that can occur. Target holders align the Ni-64 target material in beam and provide front and back face cooling that allows for increased beam currents and yields. Target holders used in these experiments are both ACSI and Washington University designed target holders. Both target holders were adapted to Cu-64 production, by adding a dedicated deionized cooling water system to the target holder. This removed the ACSI target holder from the cyclotron chilled water system as it was designed. Additionally, the water connections to the target holder and valves used to control deionized water flow were also replaced to be compatible with deionized water having a resistivity of ≥7.5 MΩ. The dedicated chilled water system for the Washington University designed target was installed to prevent radioisotope contamination of the chilled water system of the cyclotron and reduce copper contamination. The specific activity of the Cu-64 chloride and the quality of recovered Ni-64 were improved when the deionized water, the target material holder came into contact with, was significantly improved from ≥2 MΩ to ≥7.5 MΩ. To maintain the high quality water, the deionization cartridge type was changed to eliminate both cations and anions, to insure ≥7.5 MΩ quality water. These steps were taken to limit contamination of the Cu-64 chloride. Improved specific activity of Cu-64 and quality of recovered Ni-64 was obtained by reducing potential for metal contaminants by eliminating parts that were not deionized water compatible. We also changed the deionization cartridge type to eliminate both cations and anions to insure ≥7.5 MΩ quality water. These steps are intended to reduce Cu, Ni, Fe, Zn, and/or Co contamination or keep Cu, Ni, Fe, Zn, and/or Co contamination to a minimum. The improved target holder specifically aided the objective of reducing the plating area of target material to match beam spot includes a key method, allowing bombardment of non-symmetrical targets. Specialized Processing The Cu-64 separation module was constructed from HCl resistant materials where possible—special attention was paid to avoid iron and zinc based materials. When unavoidable the components made of stainless steel were coated with Teflon™ materials. Dissolution of Ni-64 containing Cu-64 with 6 N HCl occurred in a gated Teflon™ dissolution vessel (any plastic that is HCl and heat resistant to 260° C. would be suitable) closed during heating. The Teflon™ gate valve allows for hands free target addition and contains hot acid under pressure without contaminating the Cu-64 chloride. Separation of Ni-64 and Cu-64 was performed by controlled liquid chromatography this step optimizes both the recovery of the Ni-64 and purity of the Cu-64 chloride. The Cu-64 separation module design (see e.g., FIG. 1A-FIG. 1D), improved previous versions and was optimized to address issues experienced using the manual remote system. The latest design uses vacuum, pressure, and syringe drives to affect the flow of chemicals through the system and enables the standardization of the Ni-64 recovery and Cu-64 chloride yield. It is believed that the disclosed system is the first system to use all of the above methods for moving liquids through the automation system. While a single method could be used to effect movement of liquids, using all three for specific tasks have enabled improved reliability and % radiochemical yields. The dissolution vessel was modified to improve reliability and eliminate the need to orient the target holder for optimal dissolution of the Ni-64 containing Cu-64 from the gold disk. The reflux condenser on past version of the Cu-64 separation model intended to contain HCl vapor during heating was removed in favor of an in house developed Teflon™ gate valve that allow the generation of pressure within the digestion vessel. This has proven more effective at containing the HCl acid vapor than the water-cooled reflux condenser and decreased the difficulty of installing the module in a standard hot cell. The Teflon™ digestion vessel is contained in aluminum housing that is heated to 125-140° C. during digestion and has cooling fin to allow for rapid cooling of the digestion vessel and contents. This allows the contents of the digestion vessel to be move to ion exchange column with shorter cool down periods. Additionally the bottom is conical, having a Teflon™ spacer added to the vessel to eliminate the need to orient the target and prevents blockage of the fluid pathway by the gold disk substrate. The flow pathways were optimized for precise fluid flow and easy replacement of chemical traps intended to contain acid vapor and Cu-64 in the unlikely event it aerosolized. Appropriate cleaning of the automated separation module was simplified with dedicated fluid pathways and proved more effective at maintaining high specific activity of the product than disposable tubing, believed to be the result of small dead volume using non-disposable fluid pathways versus disposable. The dissolution vessel was designed allow for automatic delivery of the target from the cyclotron using dedicated carriers transported from the cyclotron vault to the hot cell using vacuum. Once in the hot cell, the carrier is automatically opened to drop the target in the dissolution vessel that is then closed by the gate valve to begin the process of separating the Cu-64 from the gold disk target holder. The carrier is then returned to the cyclotron vault when needed to automatically collect the next Cu-64 target. The solid target transfer system was designed with specialized station in the hot cell module that allows the target to be added into the dissolution vessel from a specialized carrier automatically and returned the cyclotron vault target drop. The Cu-64 chloride produced is eluted in 0.5 M HCl, to be useful in labeling, the 0.5 M HCl Cu-64 Chloride is evaporated to dryness using trapping systems to neutralize the 0.5 M HCl. It is then reconstituted in microliter amounts of 0.1 M HCl with the quantity of 0.1 M HCl determined by need concentrations. Improved Process Of the important steps in producing high purity and specific activity radionuclides with proton irradiations, one of the more complicated to achieve is limiting the amount of target material needed to produce thick target yields for the planned proton energy bombardment. This was accomplished by degrading the energy of the beam to below 14.5 MeV and focusing of the proton beam. Performing this step usually results in an asymmetric shaped beam strike. As a result, the asymmetric beam shape using a typical or conventional target and target holder system requires more target material than is necessary to reliably produce radionuclides in high yields. This unnecessary target material can increase the cost to produce a radioisotope and negatively impact the specific activity. There are numerous methodologies for determining the size, shape, and intensity of a proton beam produced by a particle accelerator. The present invention describes a method that allows for further minimization of the target material needed, in the present case, Ni-64 to produce Cu-64 once the beam shape has been determined. As part of the electroplating process, an insulator was applied on the target back to be plated with the target material made of gold or platinum that allowed for shaping of the target material to closely match the area of the beam strike area (see e.g., FIG. 4). For example, if the beam spot is an elongated oval, and the beamline opening is a circle, the improved target shape would be an oval that is approximately the size of the overlapping beamline opening and beamspot, such as an oval (see e.g., FIG. 4). The target back was keyed to assure the orientation of the target material with the beam spot (see e.g., FIG. 5). The target holder is a specialized system that holds the target back and material in the beam strike area of the proton accelerator and provides cooling necessary to dissipate the heat from the bombardment. Additionally the target holder system is designed to clear or remove the cooling water, drying the target back in the process. The target holder is designed to accept the keyed target back that provides for the target material to be orientated to the beam strike. An insulated target holder mounting flange to the beamline insures accurate beam current measurements on the target back and target material and allows for better beam steering (see e.g., FIG. 6). The full implementation of this process reduced the amount of target material needed to produce Cu-64 in high yield of 7.5 Ci at saturation, reliably producing 150 mCi/μA with the specific activity expected to routinely exceed 300 mCi/μg (see e.g., Table 1). TABLE 1Specific activities obtained using various methods.TransistioningPatent ApplicationPrevious MethodsMethodsMethod (Partial)mCi/mCi/mCi/DateμgDateμgDateμgJan. 3, 201244Jan. 7, 2014138Jan. 3, 2018354Jan. 10, 2012181Jan. 14, 2014172Jan. 9, 2018240Jan. 12, 201288Jan. 21, 2014158Jan. 16, 2018375Jan. 17, 2012167Jan. 28, 2014271Jan. 23, 2018619Jan. 31, 2012290Feb. 4, 2014115Jan. 30, 2018859Feb. 7, 2012161Feb. 11, 2014430Feb. 6, 2018885Feb. 14, 201277Feb. 18, 2014226Feb. 13, 2018702Feb. 21, 2012239Mar. 6, 2014219Feb. 15, 2018479Feb. 28, 2012219Mar. 11, 2014397Feb. 20, 2018648Mar. 6, 2012110Mar. 18, 2014286Feb. 22, 2018465Mar. 8, 201217Mar. 25, 2014293Feb. 27, 2019349Mar. 20, 201230Apr. 1, 2014230Mar. 1, 2018308Mar. 27, 201236Apr. 3, 2014145Mar. 3, 2018335Average128Average237Average509 |
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abstract | A direct pool cooling type passive safety grade decay heat removal method and system for removing core decay heat in a pool type liquid metal reactor when a normal heat removal system breaks down. In the liquid metal reactor comprising a reactor vessel, the interior of which is partitioned into a hot pool above a core and a cold pool around the core so that liquid level difference between the hot pool and the cold pool is maintained by a primary pumping head under normal steady-state conditions, is disposed at least one circular vertical tube in such a manner that the sodium in the circular vertical tube is maintained with the same liquid level as the liquid level of the sodium in the cold pool. In the circular vertical tube is disposed a sodium-sodium heat exchanger, which is connected to a sodium-air heat exchanger mounted above a reactor building via a heat removing sodium loop, in such a manner that it is placed at the position higher than a liquid level of the sodium in the cold pool under the normal steady-state conditions. |
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claims | 1. A contour collimator for radiotherapy, comprisinga plurality of plate-shaped diaphragm elements provided in a guiding block and movably arranged with respect to one another to form a contour diaphragm for a radiation beam emitted by a radiation source towards the collimator, andat least one drive for moving the diaphragm elements, whereineach diaphragm element is associated with its own drive of the at least one drive, the drives of a group of diaphragm elements are arranged substantially adjacent to one another, and each drive is a linear motor, whereineach linear motor comprises a linearly movable rod directly fixed to the associated diaphragm element,wherein the linear motors of a group of diaphragm elements are arranged in horizontal and vertical rows, a vertical row of linear motors is associated with a sub-group of diaphragm elements adjacent to each other in a horizontal direction,wherein each diaphragm element comprises a portion extended towards an associated linear motor, the extended portion comprises an angled portion located at an end facing the linear motor, wherein an associated rod is fixed to the angled portion,wherein extended portions of a sub-group of the diaphragm elements are connected to the angled portions at positions shifted in a horizontal direction, andwherein extended portions of a sub-group of the diaphragm elements are offset from a longitudinal axis of the associated rods. 2. The contour collimator according to claim 1, wherein each linear motor and the associated diaphragm element are arranged substantially within a common plane. 3. The contour collimator according to claim 1, wherein the linear motors of a group of diaphragm elements are arranged parallel to each other. 4. The contour collimator according to claim 1, wherein each linear motor comprises a housing, wherein the rod is extendable through the housing. 5. The contour collimator according to claim 1, wherein each linear motor comprises coils, wherein the rod comprises magnets, wherein the rod is arranged so as to be linearly movable between the coils. 6. The contour collimator according to claim 1, wherein the rod is welded or screwed to the associated diaphragm element. 7. The contour collimator according to claim 1, wherein the angled portions of a sub-group of diaphragm elements are arranged at the same position in a horizontal direction. 8. The contour collimator according to claim 1, wherein the rod protrudes from the linear motor in a direction facing away from the diaphragm element in a retracted position of the rod. |
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summary | ||
claims | 1. A device for improving resolution capability of an x-ray optical apparatus for an x-ray incident from a direction of incidence, comprising:a mirror element comprising a mirror edge formed as a cylindrical shell section around an edge axis,wherein the mirror element is spaced apart, in a radial direction, from a focal axis that is parallel to the direction of incidence,the edge axis is oriented at a first non-zero angle relative to the focal axis when viewed along a radial axis, andthe edge axis is oriented at a second non-zero angle relative to the focal axis. 2. The device of claim 1, wherein:the mirror element further comprises a second mirror edge adjacent the mirror edge,the second mirror edge is formed as a second cylindrical shell section around a second edge axis, anda plane comprising the edge axis and the second edge axis is tilted with respect to the direction of incidence. 3. The device of claim 2, wherein:the mirror edge corresponds to an approximation of a hyperbolic form, andthe second mirror edge corresponds to an approximation of a parabolic form. 4. The device of claim 2, further comprising another mirror element having a third mirror edge and a fourth mirror edge adjacent the third mirror edge. 5. The device of claim 4, wherein:the third mirror edge is formed as a third cylindrical shell section around a third edge axis,the other mirror element is spaced apart, in another radial direction, from the focal axis,the third edge axis is oriented at the first non-zero angle relative to the focal axis when viewed along another radial axis extending in the other radial direction, andthe third edge axis is oriented at the second non-zero angle relative to the focal axis. 6. The device of claim 5, wherein:the other mirror element is adjacent the mirror element, andthe mirror element and the other mirror element are spaced apart from the focal axis by a same distance. 7. The device of claim 6, wherein a transition between the mirror element and the other mirror element comprises a stepped offset. 8. The device of claim 4, further comprising a plurality of additional mirror elements forming a ring around the focal axis. 9. The device of claim 1, wherein a width of the mirror element is smaller than approximately one tenth of a radial distance between the mirror element and the focal axis. 10. The device of claim 9, wherein the width of the mirror element corresponds to an arc length of less than approximately two degrees in the radial direction. 11. The device of claim 1, wherein a magnitude of tilt between the edge axis and the direction of incidence is in a range of approximately one half a degree to approximately five degrees. 12. The device of claim 1, further comprising an additional mirror element spaced apart from the focal axis in the radial direction. 13. The device of claim 12, wherein a spacing of the additional mirror element from the focal axis is larger than a spacing of the mirror element from the focal axis. 14. The device of claim 1, wherein the mirror element is spaced apart, in the radial direction, from the focal axis of a focal point of the x-ray optical apparatus. 15. The device of claim 1, wherein when viewed along the radial axis:the mirror edge is arranged in a rotated position that is rotated about the radial axis relative to a reference position,in the reference position the edge axis is parallel to the focal axis, andin the rotated position the edge axis is rotated relative to the focal axis by the first non-zero angle. 16. A device for improving resolution of an x-ray optical apparatus associated with an x-ray incident from a direction of incidence, comprising:a mirror element having a first portion and a second portion adjacent the first portion,wherein the first portion comprises a first cylindrical shell section formed around a first edge axis tilted at a first non-zero angle relative to a focal axis that is parallel to the direction of incidence,the second portion comprises a second cylindrical shell section formed around a second edge axis tilted at a second non-zero angle relative to the focal axis, the second non-zero angle being different from the first non-zero angle, andthe first edge axis and the second edge axis are oriented at a third non-zero angle relative to the focal axis when viewed along a radial axis in a radial direction. 17. The device of claim 16, wherein a plane containing the first edge axis and the second edge axis is tilted at an offset angle relative to the focal axis. 18. The device of claim 17, wherein:the offset angle is in a range of approximately one half a degree to approximately five degrees, anda width of the mirror element is smaller than approximately one tenth of a radial distance between the mirror element and the focal axis. 19. The device of claim 16, wherein:the first portion comprises an approximation of a hyperbolic form, andthe second portion comprises an approximation of a parabolic form. 20. The device of claim 16, further comprising another mirror element having a third portion and a fourth portion adjacent the third portion,wherein the third portion comprises a third cylindrical shell section,the fourth portion comprises a fourth cylindrical shell section tilted relative to the third portion,the other mirror element is arranged in a stepped offset relative to the mirror element, andthe other mirror element is rotated about another radial axis that is perpendicular to the focal axis. 21. The device of claim 20, further comprising a plurality of additional mirror elements,wherein the mirror element, the other mirror element, and the plurality of additional mirror elements form a ring around the focal axis. 22. The device of claim 16, wherein when viewed along the radial axis:the first cylindrical shell section is arranged in a rotated position that is rotated about the radial axis relative to a reference position,in the reference position the first edge axis is parallel to the focal axis, andin the rotated position the first edge axis is rotated relative to the focal axis by the third non-zero angle. |
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051981840 | claims | 1. A reactor containment vessel having an outer wall structure an inside of which is divided into upper and lower drywells by means of a diaphragm floor and in which a suppression chamber is arranged, a reactor pressure vessel is supported by a pedestal and a line, a cable and a duct are disposed in and between the upper and lower drywells, said pedestal having a cylindrical structure surrounding the reactor pressure vessel, said pedestal comprising a plurality of concrete wall sections and a plurality of connecting vent sections which are arranged alternately along a circumferential direction of the cylindrical pedestal, wherein the line, the cable and the duct are arranged in each of the connecting vent sections and a vent pipe is arranged in each of the concrete wall sections so that the line, the cable and the duct and the vent pipe occupy different positions in their cross sections, said vent pipe having an open end opened to the drywell. 2. A reactor containment vessel according to claim 1, wherein each of the connecting vent sections is composed of a hollow passage section and a concrete wall section. 3. A reactor containment vessel according to claim 1, wherein a vacuum breaker means is further disposed in the reactor containment vessel at a portion above the open end of the vent pipe, said vacuum breaker means including a fixing pipe for mounting a vacuum breaker to the pedestal, said fixing pipe having one end opened to the drywell. 4. A reactor containment vessel according to claim 1, wherein said vent pipe has an end portion extended to the diaphragm floor and opened to the drywell and wherein a vacuum breaker means is further disposed in the reactor containment vessel, said vacuum breaker means being mounted to the extended portion of the vent pipe and including a fixing pipe for mounting a vacuum breaker to the pedestal, said fixing pipe having one end opened to an inside of the vent pipe. |
abstract | In one embodiment a micro-electro mechanical system is disclosed. A MEMS structure can include a frame, a movable structure and a set of structural beams to suspend the movable structure from the frame. The system can also include a set of conductor routing beams. The conductor routing beams can provide a conductive path from the frame to the movable structure. The set of structural beams can have a spring rate that is more than ten times the spring rate of the set of conductor routing beams. Accordingly, multiple routing beams can be utilized to support multiple conductors without significantly affecting the mechanical movement or dynamic properties of the movable structure. |
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abstract | The invention comprises a system for redundantly determining the state of a charged particle beam, such as beam position, direction, energy, and/or intensity. For example, the charged particle beam state is determined: (1) in an extraction system from a synchrotron, (2) in a charged particle beam transport path, and/or (3) at or about a patient undergoing charged particle cancer therapy using one or more film layers designed to emit photons upon passage of a charged particle beam, which yields information on position and/or intensity of the charged particle beam. The emitted photons are used to calculate position, direction, and/or intensity of the treatment beam in imaging and/or during tumor treatment. |
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claims | 1. A method of manufacturing a core shroud for a nuclear power plant, the method comprising steps of:setting a narrow groove between abutting surfaces of first and second metal members adjacent to each other, each of the first and second metal members having a respective thickness not less than 30 mm, with a root face on each of the abutting surfaces, each root face having its length which is between 25% and 95% of a thickness of a thinner one of the first and second metal members; andlaser welding the abutting surfaces with a welding wire to construct the core shroud, the laser welding being performed in a shielding gas including nitrogen,wherein the welding wire comprises an austenitic stainless steel including a ferrite content of 14-20% calculated from the material composition of the welding wire, and a ratio between Cr in the austenitic stainless steel and Ni in the austenitic stainless steel is 1.9-2.2. 2. The method of manufacturing a core shroud for a nuclear power plant in claim 1, wherein:a curved surface is provided in an end portion of a groove bottom portion of said narrow groove, and a width of the groove bottom portion constructed by intersecting points of an extension line of a side surface in both sides of said narrow groove and an extension line of the groove bottom portion is set to 1 mm to 4 mm, andan angle of the groove formed by the side surfaces in both sides of said groove is between 1 degree and 7 degrees. 3. The method of manufacturing a core shroud for a nuclear power plant in claim 1, wherein:a step is formed between the abutting surfaces of the first and second members, ora concavity is formed in one of the metal members and a convexity is formed in the other metal member. 4. The method of manufacturing a core shroud for a nuclear power plant as claimed in claim 1, further comprising the steps of:forming a weld groove by butting the root faces;complete penetration welding the root faces from one side or both sides; anddeposition welding said narrow groove portion while adding the welding wire. |
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summary | ||
claims | 1. A nuclear plant, comprising:a containment;a pressure relief line communicating with said containment and enabling pressure relief in said containment by blowing off a pressure relief gas;a blower device and a venturi scrubber connected in series in said pressure relief line, said venturi scrubber being disposed in a container with a scrubbing liquid;said blower device and said venturi scrubber being dimensioned to establish in said venturi scrubber, in an operating state of said blower device, a flow velocity of the pressure relief gas conveyed in said pressure relief line of more than 130 m/s;said blower device connected upstream from said venturi scrubber;said venturi scrubber including a venturi tube configured to be passively fed with a scrubbing liquid due to a negative pressure at the constriction of said venturi tube, andsaid venturi tube is formed with an entry region configured to be fed with the scrubbing liquid. 2. The nuclear plant according to claim 1, wherein said blower device and said venturi scrubber are dimensioned to establish a flow velocity of the pressure relief gas of more than 180 m/s in said venturi scrubber. 3. The nuclear plant according to claim 1, wherein said blower device is a radial fan with a rated speed of more than 10,000 rpm and a pressure of at least 200 mbar. 4. The nuclear plant according to claim 3, wherein said blower device is rated for a pressure of more than 500 mbar. 5. The nuclear plant according to claim 1, wherein said venturi scrubber comprises a multiplicity of venturi tubes having outlets, a comparatively large number of said venturi tubes are disposed with the respective said outlets above an intended setpoint level of the scrubbing liquid, and a comparatively small number of said venturi tubes are disposed with an outlet direction directed downward. 6. The nuclear plant according to claim 5, wherein up to approximately 10% of said venturi tubes are disposed with the outlet direction directed downward. 7. The nuclear plant according to claim 1, wherein said venturi scrubber comprises a plurality of venturi tubes having a throat cross-sectional area and an inlet cross-section area for the scrubbing liquid, and a ratio of said throat cross-sectional area to said inlet area is less than 10:1. 8. The nuclear plant according to claim 7, wherein said ratio is approximately 3:1. 9. The nuclear plant according to claim 1, wherein said venturi scrubber comprises a plurality of substantially round venturi tubes with a throat width of less than about 80 mm. 10. The nuclear plant according to claim 9, wherein said throat width of said venturi tubes is less than about 40 mm. 11. The nuclear plant according to claim 1, wherein said venturi scrubber comprises a plurality of substantially flat venturi tubes with a throat width of less than about 100 mm. 12. The nuclear plant according to claim 1, wherein said venturi scrubber comprises a plurality of venturi tubes with a height to throat width ratio of more than 20. 13. The nuclear plant according to claim 1, wherein said venturi scrubber comprises a plurality of venturi tubes with a height to throat width ratio of more than 50. 14. The nuclear plant according to claim 1, which further comprises a scrubbing liquid reservoir connected to said container on a scrubbing liquid side thereof. 15. The nuclear plant according to claim 1, which further comprises a feedback line connecting a scrubbing liquid side of said container to an interior of said containment. 16. The nuclear plant according to claim 15, wherein said feedback line is connected via said pressure relief line to the interior of said containment. 17. The nuclear plant according to claim 16, wherein said container is disposed geodetically lying at least approximately 5 m higher than an exit point of said pressure relief line from said containment. 18. The nuclear plant according to claim 17, wherein said container is disposed at least 10 m above said exit point. 19. The nuclear plant according to claim 1, wherein said pressure relief line, said blower device, and said venturi scrubber together form a pressure relief and activity retention system, and wherein an electrical power supply of the system components of said pressure relief and activity retention system, including control systems thereof, is constructed independently of the nuclear plant. 20. The nuclear plant according to claim 1, wherein said blower device is dimensioned so that, taking into account gases and vapor mixtures and leaks produced during incidents in a core region, a negative pressure of less than 5 mbar in an interior of said containment, a positive head pressure of approximately 500 mbar on a pressure side of said blower device is established during operation of said blower device. 21. The nuclear plant according to claim 1, which further comprises at least one of a centrifugal drop separator and a fiber separator connected in said pressure relief line downstream of said venturi scrubber. 22. The nuclear plant according to claim 21, wherein said fiber separator has fibers with a thickness of more than 50 μm. 23. The nuclear plant according to claim 21, wherein said fiber separator has fibers with decreasing fiber thickness. 24. The nuclear plant according to claim 1, which further comprises a metal fiber filter with a fiber thickness of up to 5 μm connected in said pressure relief line downstream of said venturi scrubber. 25. The nuclear plant according to claim 24, wherein said metal fiber filter has stainless steel fibers or sintered filter fibers with pore or fiber diameters of less than 5 μm. 26. The nuclear plant according to claim 1, wherein the scrubbing liquid in said container has a pH of at least 9. 27. A method for relieving pressure in the nuclear plant according to claim 1, which comprises:subjecting the venturi scrubber to a flow velocity of the pressure relief gas conveyed in said pressure relief line of more than 130 m/s; andconnecting said blower device upstream from said venturi scrubber. 28. The method according to claim 27, which comprises setting the flow velocity to more than 180 m/s. 29. The nuclear plant according to claim 1, wherein: said venturi tube has at least one feature selected from the group consisting of: a nozzle with a nozzle circumference and an annular slot feed around said nozzle circumference, a throat width of less than 80 mm, a flat construction with a throat width of less than 100 mm, a height to throat width ratio of more than 20. |
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053848128 | description | DETAILED DESCRIPTION OF THE INVENTION Referring now to the figures, wherein similar structures common to each figure will be referenced by the same reference numbers throughout this specification for simplicity of exposition, a cabling arrangement of the present invention for a nuclear reactor vessel is illustrated in three different positions in FIGS. 1-3. Nuclear reactor vessel 1 is located within a containment (not shown). A structural wall 5 within the containment spaced from reactor vessel 1 and extending to about the elevation of an IHP 7 sealed to the top of reactor vessel 1 at flange 8 defines a cavity 9 that is filled with water during refueling of the reactor. IHP 7 consists of a reactor vessel head 11, control rod drive mechanisms (CRDM's) (not shown), control rod position indicators (RPI's) (not shown), cooling fans 13 and other associated hardware. An operating deck 15, typically supported by wall 5 and located outside cavity 9 distal from reactor vessel 1, separates a sub--space 17 below deck 15 on a far side 19 of wall 5 from an operating area 21 above deck 15. Power, control and other electrical cables 23 to the CRDM's or RPI's are run from connector plates 25, 27 mounted on IHP 7 where cables 23 are connected at their first ends 29, through an opening 31 in deck 15, and then to control panels 33 located in sub-space 17 where cables 23 are connected at their second ends 35 (FIG. 1). Cavity 9 is typically filled with water during refueling of reactor vessel 1 when reactor vessel head 11 is removed. Prior to refueling, first ends 29 of all cables 23 must be disconnected from IHP 7 and removed from the area around cavity 9, and preferably removed into sub-space 17 (FIG. 3). A movable frame 41 is provided to facilitate removal of cables 23 from an area around reactor vessel 1 and from operating area 21 before refueling, and also to facilitate reconnection of cables 23 to IHP 7 after refueling and before start-up of the reactor. Frame 41 supports a length of each cable extending through frame 41, and is movable, with cables 23, between a first position 43 outside sub-space 17 proximate head package 7 (FIG. 1) and a second position 45 in sub-space 17 (FIG. 3). Frame 41 in first position 43 is oriented generally horizontally and straddles a top 47 of wall 5. In second position 45, frame 41 is oriented about vertically proximate far side 19 of wall 5. A pivot arrangement 49 near a first end 51 of frame 41 distal from reactor vessel 1 and overhanging sub-space 17 permits frame 41 to pivot between first position 43 and a substantially vertically oriented intermediate position 53 (FIG. 2). Frame 41 can be moved between first position 43 and intermediate position 53 by any of a variety of mechanisms known in the mechanical arts. For example, frame 41 can be hoisted and lowered with removable cables 54 attached to an electrically powered overhead winch (not shown). Frame 41, while vertically oriented, is guided through opening 31 along a predetermined path between intermediate position 53 and second position 45 by a guide mechanism 55. Guide mechanism 55 can include, preferably, a track 57 fixed in an about vertical orientation proximate distal side 19 of wall 5 and means 58 located near first end 51 of frame 41 engaging track 57 such that movement of frame 41 is restricted to the predetermined path parallel to track 57 between the intermediate position 53 and second position 45. Frame 41 can be raised and lowered into sub-space 17 by the same mechanism that moves frame 41 between first position 43 and second position 45, or guide mechanism 55 can further include a separate motive system 59 operably connected to the frame for providing a motive force for lifting, or lifting and lowering, the frame between second position 45 and intermediate position 53. The motive system can be powered by any number of standard modes of powering lift systems, such as, for example, electric motors, hydraulics, and pneumatics, that are found in the elevator and fork-lift arts. Referring now also to FIGS. 4-6, frame 41 preferably includes a connector plate 61 at a second end 63 opposite first end 51 and proximate head package 7 when frame 41 is in first position 43, and through which each of cables 23 pass in spaced relation. The frame can also advantageously include a retraction system for retracting the ends of the cables toward the connector plate after they are disconnected from the IHP. The retraction system can, for example, spring bias the cables or use counterweights to retract the cables. FIG. 6 illustrates a plurality of elongated tension springs 65, each having a first end 67 proximate connector plate 61 connected to a different one of the plurality of cables 23, and each having a second end 68 distal from connector plate 61 connected to a fixed member 69 within frame 41. The springs 65 bias each of cables 23 such that a connector 71 at first end 29 of each of cables 23 is retracted towards connector plate 61 when each of cables 23 is disconnected from head package 7. Horizontal cross bars 73 extending between opposite sides 75 and 77 of frame 41, as illustrated in FIG. 5, provide support to at least some of the plurality of cables 23 between first end 51 of frame 41 and second end 63 of frame. Vertically arranged spacers 79 prevent crossing of at least some of cables 23 between first end 51 of frame 41 and second end 63 of frame 41. First end 51 of frame 41 is preferably open such that cables 23 freely hang down out of frame 41 in all frame positions and extend in catenaries to control panels 33 at their second ends 35 (FIGS. 1-3). Removable cover plates (not shown) can be used, if desired, to cover opening 31 and provide more usable deck space when frame 41 is in second position 45 in sub-space 17. A temporary platform 81 provides operator access to first ends 29 of cables 23 for connecting them to IHP 7 when frame 41 is in first position 43. A seismic hold-down 83 of a type known in the art, such as a clevis arrangement, at top 47 of wall 5 latches to frame 41 and provides stability in the event of a strong vibration. Whereas particular embodiments of the present invention have been described above for purposes of illustration, it will be appreciated by those skilled in the art that numerous variations of the details may be made without departing from the invention as described in the appended claims. |
051475995 | description | DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, 1 designates the fuel assembly, which is composed of a large number of long fuel rods retained by spacer lattices 2. Between the fuel rods 1 there are arranged guide tubes 3, which are also kept in predetermined positions by the spacer lattices 2. The guide tubes 3, which are somewhat longer than the fuel rods 1 and extend somewhat above and below the ends of the fuel rods, are fixed to the top tie plate 4 and the bottom tie plate 5. The detail 6, which shows the upper part of the attachment of a guide tube 3 to the top tie plate 4, is shown enlarged in FIG. 2. In FIG. 2, the upper end of the guide tube 3 is joined to a top sleeve 7 by means of a number of beads. The upper end 8 of the top sleeve 7 is somewhat reinforced and inside of this part a peripheral slot 9 is arranged. This corresponds to the previously mentioned first locking element. Through the top tie plate 4 a hole 10 is provided. Through this hole there is inserted from above a guide sleeve 11 provided with a flange 12. This guide sleeve 11 is provided with a bead 13 surrounding the sleeve 11, this bead 13 constituting the mentioned second locking element. The bead 13 is to fit into the slot 9. The guide sleeve 11 is also provided with a slit 14 (see FIG. 4). A locking sleeve 15 is inserted into the guide sleeve 11. Further, a seat 16 for the top sleeve 7 is bored in the top tie plate 4. In FIG. 6 the bead 13 of the guide sleeve has been filled up. FIG. 3 shows the upper part 8 of the top sleeve 7 with the slot 9. FIG. 4 shows the guide sleeve with the slit 14 and FIG. 5 the locking sleeve 15. The mounting operation is carried out such that the top tie plate 4 is placed on the guide tubes 3 so that the upper ends 8 of the top sleeves 7 are guided into the seats 16. Then a guide sleeve 11 is pressed down through the hole 9, whereupon the guide sleeve, because of the slit 14, rebounds so that it enters the hole in spite of the bead 13. It is pressed in so far that the bead falls down into the slot 9, the guide sleeve 11 and the top sleeve 7 thus being locked to each other. The length of the guide sleeve 11 is then adapted such that, at the very moment when the bead 13 falls down into the slot 9, the flange 12 impinges against the upper part of the top tie plate 4. In this way a stable locking of the top tie plate 4 to the guide tubes 3 is achieved. To prevent the bead 13 from being pulled out of the slot 9, a locking sleeve 15 is then inserted into the guide sleeve 11. In this way the first locking element, the slot 9, is interlocked to the second locking element, the bead 13. To ensure that also the locking sleeve 15 is not detached, it can be secured by a swelling (not shown) over the bead 13 or below the sleeve 11 in those cases where the bead 13 according to FIG. 6 is not filled. It would, of course, be possible to have other forms of locking elements between the top sleeve and the guide sleeve, such as, for example, different forms of resilient hooks or the like. When the top tie plate is to be removed, first the locking sleeves 15 and then the guide sleeves 11 are removed. Thereafter, the top tie plate 4 rests completely freely on the top sleeves 7 of the guide tubes 3. |
045432333 | summary | BACKGROUND OF THE INVENTION This invention relates to positioning and load bearing pads on fuel ducts for liquid metal cooled nuclear reactor fuel assemblies, especially for sodium cooled nuclear reactor fuel assemblies. Fuel assemblies for nuclear reactors may be enclosed within a duct which serves to direct coolant flow through the fuel assembly. The fuel assemblies of the reactor are typically arranged in a grouping called the reactor core, which may contain hundreds of fuel assemblies. The array of fuel assemblies may cause adjacent fuel assembly ducts to abut on one another or surfaces of a core support grid. The fuel assembly duct may be provided with load pad structure, perhaps with a specially hardened surface, to bear contact between adjacent ducts or between ducts and a support grid. Such load pad is intended to endure chaffing and perhaps establish a desired clearance between ducts. In current designs, the load pads are either welded to the ducts or are integral to the duct walls. The ducts are usually built of 316 stainless steel. As a result of radiation induced swelling, the useful life of a duct is limited to about three reactor fuel cycles. In an effort to extend duct life the use of ferritic steel for the ducts is being considered with the consequence that process steps used to form welded or integral load pads have become extremely difficult. It is therefore desired to provide a load pad which is not welded or integral to the fuel assembly duct. SUMMARY OF THE INVENTION The invented load pad is a mechanically attached structure which fits snugly into a duct wall receptacle and is secured therein by a spring loaded, spirally wound ring which mates with a groove in the pad and a groove in the duct wall. The load pad has a hardened surface suitable for frictional wear resistance. |
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claims | 1. A charged-particle beam exposure apparatus comprising:a charged-particle beam source for emitting a charged-particle beam;an electrooptic system array which has a plurality of electron lenses and forms a plurality of intermediate images of said charged-particle beam source by the plurality of electron lenses; anda projection electrooptic system for projecting on a substrate the plurality of intermediate images formed by said electrooptic system array,said electrooptic system array including:at least two electrodes arranged along paths of a plurality of charged-particle beams, each of said at least two electrodes having a plurality of apertures on the paths of the plurality of charged-particle beams; anda shield electrode which is interposed between said at least two electrodes and has a plurality of shields corresponding to the respective paths of the plurality of charged-particle beams. 2. A charged-particle beam exposure apparatus comprising:a charged-particle beam source for emitting a charged-particle beam;an electrooptic system array which has a plurality of electron lenses and forms a plurality of intermediate images of said charged-particle beam source by the plurality of electron lenses; anda projection electrooptic system for projecting on a substrate the plurality of intermediate images formed by said electrooptic system array,said electrooptic system array including:upper, middle, and lower electrodes arranged along paths of a plurality of charged-particle beams, said upper, middle, and lower electrodes having pluralities of apertures on the paths of the plurality of charged-particle beams; anda lower shield electrode which is interposed between said lower and middle electrodes and has a plurality of shields corresponding to the respective paths of the plurality of charged-particle beams. 3. A device manufacturing method comprising the steps of:installing a plurality of semiconductor manufacturing apparatuses including a charged-particle beam exposure apparatus in a factory; andmanufacturing a semiconductor device by using the plurality of semiconductor manufacturing apparatuses,the charged-particle beam exposure apparatus having:a charged-particle beam source for emitting a charged-particle beam;an electrooptic system array which has a plurality of electron lenses and forms a plurality of intermediate images of the charged-particle beam source by the plurality of electron lenses; anda projection electrooptic system for projecting on a substrate the plurality of intermediate images formed by the electrooptic system array,the electrooptic system array including:at least two electrodes arranged along paths of a plurality of charged-particle beams, each of the at least two electrodes having a plurality of apertures on the paths of the plurality of charged-particle beams; anda shield electrode which is interposed between the at least two electrodes and has a plurality of shields corresponding to the respective paths of the plurality of charged-particle beams. 4. The method according to claim 3, further comprising the steps of:connecting the plurality of semiconductor manufacturing apparatuses by a local area network;connecting the local area network to an external network of the factory;acquiring information about the charged-particle beam exposure apparatus from a database on the external network by using the local area network and the external network; andcontrolling the charged-particle beam exposure apparatus on the basis of the acquired information. |
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054689708 | claims | 1. Device for collimating divergent beams of a radiation, said device comprising a plurality of parallel plys of wires which are made of or coated with a material able to absorb the radiation so as to collimate a beam of the radiation which propagates along a direction which is substantially parallel to the plys. 2. Device according to claim 1, wherein the wires are round. 3. Device according to claim 1, wherein in each ply, each wire of row n for any whole number n greater than or equal to 3 is tangent to a plane which passes between the wire of row n-1 of this ply and the wire of row 1 of an adjacent ply and which is tangent to this wire of row 1 and this wire of row n-1, the wires of row 1 corresponding to an inlet of the device. 4. Device according to claim 1, wherein said material is able to absorb neutrons, the device thus being able to collimate beams of neutrons. 5. Device according to claim 4, wherein said material is boron. 6. Device according to claim 1, wherein in each ply, spacing of the wires increases from the inlet to the outlet of the collimator. 7. Device according to claim 1, wherein the wires are individually stretched between two parallel plates. 8. Process for collimating a divergent beam of a radiation, said process including the steps of providing a device comprising a plurality of parallel plys of wires which are made of or coated with a material able to absorb the radiation, and sending said beam toward said device along a direction which is substantially parallel to the plys. |
abstract | A method and system for the thermoelectric conversion of nuclear reactor generated heat including upon a nuclear reactor system shutdown event, thermoelectrically converting nuclear reactor generated heat to electrical energy and supplying the electrical energy to a mechanical pump of the nuclear reactor system. |
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abstract | A nuclear power plant according to an embodiment comprises: a reactor well; a reactor well upper lid; an operation floor; an operation floor area wall; a standby gas treatment system; and a reactor well exhaust section to release the gas inside the reactor well to the environment without releasing the gas into the operation floor area in an event of a predetermined accident, e.g., causing diminished cooling of a containment vessel or otherwise increasing its temperature. The standby gas treatment system includes: a suction pipe to take in gas inside the reactor building; an exhaust fan; a standby gas treatment system exhaust pipe; a heater that is disposed between the suction pipe and the standby gas treatment system exhaust pipe; and a filter to filter the gas heated by the heater and to send the gas to the standby gas treatment system exhaust pipe. |
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description | This application is a national phase entry under 35 USC 371 of International Patent Application No. PCT/CN2018/084648 filed on Apr. 26, 2018, which claims priority to Chinese Patent Application No. 201720620521.6 filed on May 31, 2017, which are incorporated herein by reference in their entirety. The present disclosure relates to the field of radiation therapy instruments, and in particular, to a collimating body and a multi-source focusing radiation therapy head. Radiation therapy, as a means of cancer treatment, is currently widely used in medicine. A multi-source focusing radiation therapy, one of the radiation therapy technologies, integrates modern computer technologies, stereotactic technologies and surgeries, which may geometrically focus the rays emitted by the radioactive source, concentrate on niduses, and destroy the tissue within the target in a one-time and lethal manner, while the rays pass through normal human tissue with little damage. The existing multi-source focusing radiation therapy equipment includes a roller, a treatment head and a treatment bed. The treatment head is mounted on the roller, and the roller drives the treatment head to rotate around a focus. The treatment bed is located on a side of the roller in an axial direction, and the treatment bed may move along the roller in the axial direction through the center opening of the roller. The treatment head sequentially includes a shielding body, a source body and a collimating body from the outside to the inside, and the shielding body is located outside the source body for shielding radiation of the radioactive source to the external environment. The source body is provided with a plurality of carrier chambers and ray through-holes, and the carrier chambers are used for loading the radioactive source. The collimating body is provided with a plurality of conical collimating holes for focusing beams emitted by the radioactive source. During treatment, the collimating holes on the collimating body are aligned with the ray through-holes on the source body, and ray beams emitted by the radioactive source in the source body pass through the ray through-holes and the collimating holes and converge to the focus to treat the affected regions of the patient on the treatment bed. Since the shapes of the affected regions of the patient are often irregular, the affected regions in different positions require different sizes and shapes of the radiation field. During the treatment, for the treatment of different affected regions, the collimating bodies having different aperture sizes need to be changed, which makes the treatment process complicated. In order to simplify this process, a plurality of the collimating holes having different aperture sizes are disposed on one collimating body, and the collimating body is moved to match the collimating holes having different aperture sizes according to the treatment needs. With the improvement of precision requirements of modern radiation therapy technologies, not only the accuracy of the shape of the radiation field projected onto the tumor is required, but also the accuracy of the radiation doses projected onto the tumor is required. It is difficult to satisfy the requirement of high accuracy treatment by using the existing collimating bodies having a plurality of the collimating holes with different aperture sizes because of the single shape of the radiation field and low control accuracy of dose rates. Therefore, how to provide a collimating body and a multi-source focusing radiation therapy head that may adjust the shapes of the radiation field and improve the accuracy of the dose control at the focus becomes an urgent problem to be solved in the art. The purpose of the present disclosure is to provide a collimating body and a multi-source focusing radiation therapy head that may adjust a shape of the radiation field at the focus, increase a dose control range and improve accuracy of the dose control. The purpose of the present disclosure is achieved by the following technical solutions. A collimating body includes a first collimating portion, and the first collimating portion includes a first collimating hole set; a second collimating portion, and the second collimating portion includes a second collimating hole set; the first collimating portion and the second collimating portion are arranged side by side in a side-by-side direction and closely fitted; the first collimating portion and the second collimating portion are able to move oppositely in a direction perpendicular to the side-by-side direction, so as to align or stagger the first collimating hole set and the second collimating hole set. Preferably, the first collimating portion includes at least one first collimating hole set; the second collimating portion includes a plurality of second collimating hole sets, and the plurality of second collimating hole sets are distributed in the direction perpendicular to the side-by-side direction; at least one of the plurality of second collimating hole sets is configured in a way that an aperture size of each second collimating hole in the at least one of the plurality of second collimating hole sets is not completely equal to an aperture size of each second collimating hole in other second collimating hole sets. Preferably, the second collimating portion includes at least one second collimating hole set; the first collimating portion includes a plurality of first collimating hole sets, and the plurality of first collimating hole sets are distributed in the direction perpendicular to the side-by-side direction; at least one of the plurality of first collimating hole sets is configured in a way that an aperture size of each first collimating hole in the at least one of the plurality of first collimating hole sets is not completely equal to an aperture size of each first collimating hole in other first collimating hole sets. Preferably, the first collimating portion includes a plurality of first collimating hole sets, and an aperture sizes of each of the plurality of first collimating hole sets is not completely equal to each other; the second collimating portion includes a plurality of second collimating hole sets, and an aperture sizes of each of the plurality of second collimating hole sets is not completely equal to each other. Preferably, the number of the first collimating hole sets included in the first collimating portion is equal to the number of the second collimating hole sets included in the second collimating portion. Preferably, the first collimating hole set includes a plurality of first collimating holes having a same aperture size, and the second collimating hole set includes a plurality of second collimating holes having a same aperture size. Preferably, the first collimating hole set includes a plurality of first collimating holes with aperture sizes which are not completely equal to each other, and the second collimating hole set includes a plurality of second collimating holes with aperture sizes which are not completely equal to each other. Preferably, the number of the first collimating holes included in each first collimating hole set is equal to the number of the second collimating holes included in each second collimating hole set. Preferably, the number of the first collimating holes included in each first collimating hole set is different from the number of the second collimating holes included in each second collimating hole set. Preferably, the first collimating portion includes a plurality of first collimating hole sets, and the second collimating portion includes a plurality of second collimating hole sets, and an aperture size of each of the plurality of first collimating hole sets is equal to an aperture size of each of the plurality of second collimating hole sets in one-to-one correspondence. Preferably, the collimating body further includes a first driving portion, and the first driving portion is configured to drive the first collimating portion to move in the direction perpendicular to the side-by-side direction relative to the second collimating portion. Preferably, the collimating body further includes a first brake portion, and the first brake portion is configured to limit a movement of the first driving portion. Preferably, the collimating body further includes a second driving portion, and the second driving portion is configured to drive the second collimating portion to move in the direction perpendicular to the side-by-side direction relative to the first collimating portion. Preferably, the collimating body further includes a second brake portion, and the second brake portion is configured to limit a movement of the second driving portion. Preferably, the first collimating portion includes a first stepped portion, and the second collimating portion includes a second stepped portion that cooperates with the first stepped portion. A multi-source focusing radiation therapy head includes any one of the above collimating bodies. A collimating body of the present disclosure includes the first collimating portion and the second collimating portion. The first collimating portion and the second collimating portion are arranged side by side in the side-by-side direction and closely fixed. The first collimating portion includes a first collimating hole set, and the second collimating portion includes a second collimating hole set. The first collimating portion and the second collimating portion may be oppositely moved in the direction perpendicular to the side-by-side direction, so as to align or stagger the first collimating hole set and the second collimating hole set. In this manner, relative positions of the first collimating portion and the second collimating portion may be adjusted in the direction perpendicular to the side-by-side direction, so as to adjust relative positions of the first collimating hole sets and the second collimating hole sets, realize different combinations of the first collimating hole sets and the second collimating hole sets, adjust shapes and sizes of the radiation field, provide more kinds of shapes of the radiation field, and increase a dose control range at the focus and improve an accuracy of the dose control. In the description of the present disclosure, it will be understood that the orientation or positional relationship indicated by the terms “center”, “lateral”, “upper”, “lower”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer” and so on are based on the orientation or positional relationship shown in the drawings, and is merely for the convenience of description of the present disclosure and the simplification of the description, rather than indicate or imply that the device or component referred to must have a particular orientation, configuration and operation in a particular orientation, and thus cannot be construed as the limitation of the present disclosure. Moreover, the terms “first” and “second” are only used for describing purpose, and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined with “first” and “second” may explicitly or implicitly include one or more of the features. In the description of the present disclosure, the term “a plurality of” means two or more than two, unless specified otherwise. Additionally, the terms “comprising”, “including”, and any deformation thereof are intended to cover a non-exclusive inclusion. In the description of the present disclosure, unless specified or defined otherwise, it will be noted that the terms “mounted”, “connected”, “coupled” should be understood broadly, for example, a fixed connection, a detachable connection, or an integral connection; a mechanical or electrical connection; a direct connection or an indirect connection via intermediaries; an inner communication between two elements. The specific meanings of the above terms in the present disclosure can be understood by those ordinary skilled in the art according to specific situations. The present disclosure will be further described in combination with the drawings and preferred embodiments. As shown in FIG. 1 and FIG. 2, a collimating body is disclosed in this embodiment, including a first collimating portion 11 and a second collimating portion 12. The first collimating portion 11 and the second collimating portion 12 are arranged side by side in a side-by-side direction and closely attached. The first collimating portion 11 includes a first collimating hole set 21, and the second collimating portion 12 includes a second collimating hole set 22. The first collimating portion 11 and the second collimating portion 12 may be oppositely moved in a direction perpendicular to the side-by-side direction, so as to align or stagger the first collimating hole set 21 and the second collimating hole set 22. In this manner, relative positions of the first collimating portion 11 and the second collimating portion 12 may be adjusted in the direction perpendicular to the side-by-side direction, so as to adjust relative positions of the first collimating hole set 21 and the second collimating hole set 22, realize different combinations of the first collimating hole set 21 and the second collimating hole set 22, adjust shapes and sizes of radiation field, provide more kinds of shapes of the radiation field, and increase a dose control range at a focus and improve an accuracy of the dose control. The number of the first collimating hole sets 21 and the number of the second collimating hole sets 22 are not limited in the embodiment. The first collimating hole set 21 may be set as one set, and the second collimating hole set 22 may also be set as one set. Different shapes of the radiation field and dose adjustments may be realized by different combinations of first collimating hole sets and second collimating hole sets. Of course, the first collimating hole set 21 may be set as one set, and the second collimating hole set 22 may be set as two or more sets, so that the shape of the radiation field is more diverse. Of course, the second collimating hole set 22 may be set as one set and the first collimating hole set 21 may be set as two or more sets. It is also possible that the first collimating hole set 21 is set as two or more sets, and the second collimating hole set 22 is also set as two or more sets. The number of the first collimating hole sets 21 and the number of the second collimating hole sets 22 may be the same or different. In the embodiment, each first collimating hole set may include one first collimating hole, and may also include two or more first collimating holes. Aperture sizes of the two or more first collimating holes may be the same or different. Each second collimating hole set may include one second collimating hole, and may also include two or more second collimating holes. Aperture sizes of the two or more second collimating holes may be the same or different. The number of the first collimating holes in the first collimating hole set may be the same as or different from the number of the second collimating holes in the second collimating hole set. Aperture sizes of the first collimating holes in the first collimating hole set may be the same as or different from aperture sizes of the second collimating holes in the second collimating hole set. In the embodiment, for example, as shown in FIG. 3, the first collimating portion 11 includes one first collimating hole set 21 (FIG. 3 shows only part of structure of the first collimating portion 11. It should be understood that the first collimating portion 11 may include other numbers of first collimating hole sets, for example, two or three or five or more sets of first collimating hole sets); the second collimating portion 12 includes a plurality of second collimating hole sets 22, and the plurality of second collimating hole sets 22 are distributed in the direction perpendicular to the side-by-side direction. At least one of the plurality of second collimating hole sets 22 is configured in a way that an aperture size of each second collimating hole in the at least one of the plurality of second collimating hole sets is not completely equal to an aperture size of each second collimating hole in other second collimating hole sets. In this manner, an aperture size of each second collimating hole in the at least one of the plurality of second collimating hole sets 22 is not completely equal to an aperture size of each second collimating hole in other sets. Relative positions of the first collimating portion 11 and the second collimating portion 12 are adjusted in a relative movement direction shown in FIG. 3 to make the first collimating hole set 21 aligned side by side with the second collimating hole set 22 to form different shapes of the radiation field at the focus. As shown in FIG. 3, the first collimating portion 11 includes one first collimating hole set 21. The first collimating hole set 21 includes three first collimating holes 23 arranged side by side, and aperture sizes of the three first collimating holes 23 are the same. The second collimating portion 12 includes four second collimating hole sets 22, which are arranged in four rows, including a first second collimating hole set 221, a second second collimating hole set 222, a third second collimating hole set 223 and a fourth second collimating hole set 224. Each second collimating hole set includes three second collimating holes, aperture sizes of the three second collimating holes in a same set are the same, and the four second collimating hole sets have different aperture sizes (in this case, the aperture size of the second collimating hole set is equal to an aperture size of each second collimating hole in the set). An aperture size of the first second collimating hole set 221 may be set as the largest, an aperture size of the third second collimating hole set 223 may be set as the smallest, and an aperture size of the second second collimating hole set 222 may be set as greater than the aperture size of the third second collimating hole set 223 but less than an aperture size of the fourth second collimating hole sets 224. In this way, the relative positions of the first collimating portion 11 and the second collimating portion 12 may be adjusted, so that the first collimating hole set 21 may be aligned with the first second collimating hole set 221, or may also be aligned with the second second collimating hole set 222, or may also be aligned with the third second collimating hole set 223, or may also be aligned with the fourth second collimating hole set 224, which may form different shapes and sizes of the radiation field by alignment of different second collimating hole sets and the first collimating hole set 21. As shown in FIG. 4, in a case where the first collimating hole set 21 is aligned with one of the second collimating hole sets 22, ray beams emitted by six radioactive sources pass through the first collimating hole set 21 in the first collimating portion 11 and the second collimating hole sets 22 in the second collimating portion 12 to form two kinds of spots having different sizes. A combination of the two kinds of spots having different sizes may realize an adjustment of the shapes of the radiation field at the focus and an adjustment of a radiation dose at the focus. The ray beams are focused on the focus through the collimating holes. Since aperture sizes of the four second collimating hole sets 22 are different, the shapes and sizes of the radiation field formed at the focus may be adjusted, so as to obtain various shapes of the radiation field, and adjust the radiation dose at the focus more accurately. Of course, in the embodiment, the second collimating portion 12 may include two second collimating hole sets 22 having the same aperture sizes, as long as an aperture size of at least one of the second collimating hole sets 22 is different from aperture sizes of other second collimating hole sets 22, so as to achieve more various shapes and sizes of the radiation field. In the embodiment, the number of the first collimating holes in each first collimating hole set is not limited, and the number of the second collimating holes in each second collimating hole set is also not limited, and the above description is only an example. Exemplified in this embodiment, as shown in FIG. 5, the second collimating portion 12 includes one second collimating hole set 22 (FIG. 5 shows only part of structure of the second collimating portion 12. It should be understood that the second collimating portion 12 may include other numbers of second collimating hole sets, for example, two or three or five or more sets of second collimating hole sets). The first collimating portion 11 includes a plurality of first collimating hole sets 21, and the plurality of first collimating hole sets 21 are distributed in the direction perpendicular to the side-by-side direction. At least one of the plurality of first collimating hole sets 21 is configured in a way that an aperture size of each first collimating hole in the at least one of the plurality of the first collimating hole sets 21 is not completely equal to an aperture size of each first collimating hole in other first collimating hole sets 21. In this way, the second collimating hole sets 22 may be aligned with different first collimating hole sets 21 to form different shapes and sizes of the radiation field at the focus. For example, as shown in FIG. 5, the first collimating portion 11 includes four first collimating hole sets 21, which are arranged in four rows, including a first first collimating hole set 211, a second first collimating hole set 212, a third first collimating hole set 213 and a fourth first collimating hole set 214. Each first collimating hole set 21 includes three first collimating holes 23, aperture sizes of the three second collimating holes in a same set are the same, and aperture sizes of the four first collimating hole sets 21 are different (in this case, the aperture size of the second collimating hole set is equal to an aperture size of each second collimating hole in the set). An aperture size of the first first collimating hole set 211 may be set as the largest, an aperture size of the third first collimating hole set 213 may be set as the smallest, and an aperture of the second first collimating hole set 212 may be set as greater than the aperture size of the third first collimating hole set 213 but less than an aperture size of the fourth first collimating hole set 214. The second collimating portion 12 includes one second collimating hole set 22, the second collimating hole set 22 includes three second collimating holes 24 arranged side by side, and aperture sizes of the three second collimating holes 24 are the same. In this way, the relative positions of the first collimating portion 11 and the second collimating portion 12 may be adjusted, so that the second collimating hole set 22 may be aligned with the four different first collimating hole sets 21. The second collimating hole set 22 may be aligned with the first first collimating hole set 211, or may also be aligned with the second first collimating hole set 212, or may also be aligned with the third first collimating hole set 213, or may also be aligned with the fourth first collimating hole set 214, and aperture sizes of the four first collimating hole sets are different, which may form different shapes and sizes of the radiation field by alignment of different first collimating hole sets and the second collimating hole set. As shown in FIG. 4, in a case where the second collimating hole set 22 is aligned with one of the first collimating hole sets 21, rays are focused to a focus 9 through the collimating holes. Since the apertures sizes of the four first collimating hole sets 21 are different, the shapes and sizes of the radiation field formed at the focus may be adjusted, so as to obtain rich shapes of the radiation field, and the radiation dose at the focus may be adjusted more precisely. Of course, in the embodiment, the first collimating portion 11 may have two first collimating hole sets 21 having the same aperture size, as long as an aperture size of at least one of the first collimating hole sets 21 is different from aperture sizes of other first collimating hole sets 21, so as to achieve more various shapes and sizes of the radiation field. In the embodiment, the number of the second collimating holes in the second collimating hole sets is not limited, and the above is only an example. The number of the first collimating holes in each first collimating hole set is also not limited, and the above is only an example. Exemplified in this embodiment, as shown in FIG. 6, the first collimating portion 11 includes a plurality of first collimating hole sets 21, an aperture size of each first collimating hole in each first collimating hole set 21 is the same, and aperture sizes of the plurality of first collimating hole sets 21 are not completely equal to each other. The second collimating portion 12 includes a plurality of second collimating hole sets 22, an aperture size of each second collimating hole in each second collimating hole set 21 is the same, and aperture sizes of the plurality of second collimating hole sets 22 are not completely equal to each other. In this manner, in a case where relative positions between the first collimating portion 11 and the second collimating portion 12 are adjusted, different first collimating hole sets 21 may be aligned with different second collimating hole sets 22, thereby further increasing a diversity of the shapes and sizes of the radiation field. For example, as shown in FIG. 6, the first collimating portion 11 includes four first collimating hole sets 21, which are arranged in four rows, including the first first collimating hole set 211, the second first collimating hole set 212, the third first collimating hole set 213 and the fourth first collimating hole set 214. Each first collimating hole set 21 includes three first collimating holes 23, the aperture sizes of the three first collimating holes 23 in a same set are the same, and the aperture sizes of the four first collimating hole sets 21 are different (in this case, the aperture size of the first collimating hole set 21 is equal to an aperture size of each first collimating hole 23 in the set). The aperture size of the first first collimating hole set 211 may be the largest, the aperture size of the third first collimating hole set 213 may be set as the smallest, and the aperture size of the second first collimating hole set 212 may be set as greater than the aperture size of the third first collimating hole set 213 but less than the aperture size of the fourth first collimating hole set 214. The second collimating portion 12 includes four second collimating hole sets 22, and the four second collimating hole sets 22 are arranged in four rows, including the first second collimating hole set 221, the second second collimating hole set 222, the third second collimating hole set 223 and the fourth second collimating hole set 224. Each second collimating hole set includes three second collimating holes, aperture sizes of the three second collimating holes 24 in a same set are the same, and the aperture sizes of the four second collimating hole sets 22 are different (in this case, the aperture size of the second collimating hole set 22 is equal to an aperture size of each first collimating hole 24 in the set). The aperture size of the first second collimating hole set 221 may be set as the largest, the aperture size of the third second collimating hole set 223 may be set as the smallest, and the aperture size of the second second collimating hole set 222 may be set as greater than the aperture size of the third second collimating hole set 223 but less than the aperture size of the fourth second collimating hole set 224. In this way, in a case where relative positions of the first collimating portion 11 and the second collimating portion 12 are adjusted, the first first collimating hole set 211 may be aligned with the first second collimating hole set 221, or may also be aligned with the second second collimating hole set 222, or may also be aligned with the third second collimating hole set 223, or may also be aligned with the fourth second collimating hole set 224. The second first collimating hole set 212 may be aligned with the first second collimating hole set 221, or may also be aligned with the second second collimating hole set 222, or may also be aligned with the third second collimating hole set 223, or may also be aligned with the fourth second collimating hole set 224. Alignments of the third first collimating hole set 213 and the fourth first collimating hole set 214 with each second collimating hole set 22 are similar. Since the aperture sizes of the four first collimating hole sets 21 are not completely equal to each other, and the aperture sizes of the four second collimating hole sets 22 are not completely equal to each other, different first collimating hole sets 21 may be aligned with different second collimating hole sets 22 by adjusting the relative positions of the first collimating portion 11 and the second collimating portion 12 to obtain more various shapes of the radiation field, which may meet needs of different occasions and increase application range of products. Of course, in the embodiment, other numbers of the first collimating hole sets may be provided, such as two or three or five or more first collimating hole sets. Aperture sizes of the plurality of first collimating hole sets may also be the same in two sets, or aperture sizes of first collimating holes in a certain collimating hole set may be different. In the embodiment, other numbers of the second collimating hole sets may be provided, such as two or three or five or more second collimating hole sets. Aperture sizes of the plurality of second collimating hole sets may also be the same in two sets, or aperture sizes of the second collimating holes in a certain collimating hole set may be different. In this embodiment, the number of the first collimating hole sets and the number of the second collimating hole sets may be the same or different, for example, the above four first collimating hole sets and four second collimating hole sets may also be set as three first collimating hole sets and five second collimating hole sets, or other numbers of first collimating hole sets and other numbers of second collimating hole sets, or the like. In the present embodiment, the number of the first collimating holes in any one of the first collimating hole sets is not limited, and the number of the second collimating holes in any one of the second collimating hole sets is also not limited. The number of the first collimating holes in any one of the collimating hole sets and the number of the second collimating holes in any one of the second collimating hole sets may be same or different, for example, there are three first collimating holes in one of the first collimating hole sets, and three second collimating holes in one of the second collimating hole sets. Of course, there may be four first collimating holes in one of the first collimating hole sets, and three or five or other numbers of the second collimating holes in one of the second collimating hole sets. Exemplified in this embodiment, the number of the first collimating hole sets included in the first collimating portion is equal to the number of the second collimating hole sets included in the second collimating portion. In this way, in a case where the first collimating portion and the second collimating portion are adjusted, it is more convenient to align the first collimating hole sets and the second collimating hole sets, and align different first collimating hole sets and different second collimating hole sets, thereby conveniently and quickly switching the shapes and sizes of the radiation field. For example, as shown in FIG. 6, the first collimating portion 11 includes four first collimating hole sets 21, and the second collimating portion includes four second collimating hole sets 22, and of course, other numbers of the first collimating hole sets 21 and the second collimating hole sets 22 may also be set, such as one, two or three or five first collimating hole sets 21 and second collimating hole sets 22. Exemplified in this embodiment, each first collimating hole set may have one or two or more first collimating holes. In a case where there are a plurality of first collimating holes, aperture sizes of the plurality of first collimating holes may be the same or different. As shown in FIG. 6, aperture sizes of the plurality of first collimating holes 23 may be the same in the embodiment. Aperture sizes of three first collimating holes 23 in the first first collimating hole sets 211 are the same, aperture sizes of three first collimating holes 23 in the second first collimating hole sets 212 are the same, aperture sizes of three first collimating holes 23 in the third first collimating hole sets 213 are the same, and aperture sizes of three first collimating holes 23 in the fourth first collimating hole sets 214 are the same. However, aperture sizes of the first collimating holes 23 in the first first collimating hole sets may be the same as or different from aperture sizes of the first collimating holes 23 in the second first collimating hole sets, aperture sizes of the first collimating holes in the third first collimating hole sets, and aperture sizes of the first collimating holes in the fourth first collimating hole sets. In this embodiment, an aperture size of each first collimating hole in each first collimating hole set may be selected to be different to increase the diversity of the shapes and sizes of the radiation field. For example, each second collimating hole set may have one or two or more second collimating holes. In a case where there are a plurality of second collimating holes, aperture sizes of the plurality of second collimating holes may be the same or different. As shown in FIG. 6, aperture sizes of the plurality of second collimating holes 24 may be the same in the embodiment. Aperture sizes of three second collimating holes in the first second collimating hole set 221 are the same, aperture sizes of three second collimating holes in the second second collimating hole set 222 are the same, aperture sizes of three second collimating holes in the third second collimating hole set 223 are the same, and aperture sizes of three second collimating holes in the fourth second collimating hole set 224 are the same. However, aperture sizes of the second collimating holes in the first second collimating hole sets may be the same as or different from aperture sizes of the second collimating holes in the second second collimating hole sets, aperture sizes of the second collimating holes in the third second collimating hole sets, and aperture sizes of the second collimating holes in the fourth second collimating hole sets. In this embodiment, an aperture size of each second collimating hole in each second collimating hole set may be selected to be different to increase the diversity of the shapes and sizes of the radiation field. Exemplified in this embodiment, the aperture sizes of the plurality of first collimating hole sets are the same as the aperture sizes of the plurality of second collimating hole sets. For example, as shown in FIG. 6, distribution of the first collimating hole sets 21 and distribution of the second collimating hole sets 22 may be symmetrically arranged, and an axis of symmetry is a straight line segment formed by an intersection of the first collimating portion 11 and the second collimating portion 12. For example, as shown in FIG. 6, the aperture size of the first first collimating hole set 211 in this embodiment is the same as the aperture size of the first second collimating hole set 221, the aperture size of the second first collimating hole set 212 is the same as the aperture size of the second second collimating hole set 222, the aperture size of the third first collimating hole set 213 is the same as the aperture sizes of the third second collimating hole set 223, and the aperture size of the fourth first collimating hole set 214 is the same as the aperture size of the fourth second collimating hole set 224. Of course, in the embodiment, other numbers of the first collimating hole sets and second collimating hole sets may be set, such as two or three or five or six first collimating hole sets and second collimating hole sets. Exemplified in the embodiment, as shown in FIG. 1, the collimating body includes a first driving portion 31, and the first driving portion 31 drives the first collimating portion 11 to move in the direction perpendicular to the side-by-side direction relative to the second collimating portion 12, so as to adjust the relative positions of the first collimating portion 11 and the second collimating portion 12 in the direction perpendicular to the side-by-side direction to align or stagger the first collimating hole sets 21 and the second collimating hole sets 22. Power sources of the first driving portion 31 may adopt motor drive, aerodynamic drive, hydraulic drive and the like. A driving connection portion of the first driving portion may be connected to the power source and the first collimating portion by adopting a telescopic rod, or connected to the power source and the first collimating portion by a gear unit, or connected power source and the first collimating portion by a worm and gear, or connected to the power source and the first collimating portion by a ball screw, or connected to the power source and the first collimating portion by a polished rod slider, or the like. As shown in FIG. 1, a transmission mode may be realized by a motor driven ball screw in this embodiment. The first driving portion 31 includes a first motor 41, and an output shaft of the first motor 41 is connected to a first lead screw 42. The first collimating portion 11 is mounted on the first lead screw 42 to drive a movement of the first collimating portion 11 as the first lead screw 42 rotates. In this embodiment, the collimating body further includes a first brake portion, and the first brake portion is configured to limit a movement of the first drive portion. In this way, during the treatment, a deflection of the first collimating portion due to factors such as gravity may be prevented in a case where the therapy head is deflected to an angle, and the first brake portion is adopted to keep the first collimating portion stationary, not deflected. The first brake portion may be a brake mounted on the power output shaft, or a brake restricting the movement of the first collimating portion, or a brake mounted on the motor shaft in this embodiment. Exemplified in the embodiment, as shown in FIG. 1, the collimating body further includes a second driving portion 32, and the second driving portion 32 drives the second collimating portion 12 to move in the direction perpendicular to the side-by-side direction relative to the first collimating portion 11. In this way, the second collimating portion 12 may be driven to move, so as to adjust the relative positions of the second collimating portion 12 and the first collimating portion 11 in the direction perpendicular to the side-by-side direction to align or stagger the first collimating hole sets 21 and the second collimating hole sets 22. Power sources of the second driving portion 32 may adopt motor drive, aerodynamic drive, hydraulic drive and the like. A driving connection portion of the second driving portion may be connected to the power source and the second collimating portion by adopting a telescopic rod, or connected to the power source and the second collimating portion by a gear unit, or connected power source and the second collimating portion by a worm and gear, or connected to the power source and the second collimating portion by a ball screw, or connected to the power source and the second collimating portion by a polished rod slider, or the like. As shown in FIG. 1, a transmission mode may be realized by a motor driven ball screw in this embodiment. The second driving portion 32 includes a second motor 43, and an output shaft of the second motor 43 is connected to the second lead screw 44. The second collimating portion 12 is mounted on the second lead screw 44 to drive a movement of the second collimating portion 12 as the lead screw rotates. The embodiment may provide only the first driving portion or only the second driving portion, or both the first driving portion and the second driving portion, which may all realize a relative movement of the first collimating portion and the second collimating portion in the direction perpendicular to the side-by-side direction. In this embodiment, the collimating body further includes a second brake portion, and the second brake portion is configured to limit a movement of the second driving portion. In this way, during the treatment, a deflection of the second collimating portion due to factors such as gravity may be prevented in a case where the therapy head is deflected to an angle, and the second brake portion is adopted to keep the second collimating portion stationary, not deflected. The second brake portion may be a brake mounted on the power output shaft, or a brake restricting the movement of the second collimating portion, or a brake mounted on the motor shaft in this embodiment. Exemplified in this embodiment, as shown in FIG. 7, the first collimating portion 11 includes a first stepped portion 45, and the second collimating portion 12 correspondingly includes a second stepped portion 46 that cooperates with the first stepped portion 45. In this way, a shape of a fitting surface of the first collimating portion 11 and the second collimating portion 12 is a complementary stepped shape to ensure a close fit between the first collimating portion 11 and the second collimating portion 12 to prevent radiation leakage. In the embodiment, the first collimating portion 11 and the second collimating portion 12 may also respectively include two or more stepped portions. For example, the first collimating portion 11 includes two or more stepped portions, and the second collimating portion 12 correspondingly includes two or more stepped portions. The embodiment is not limited to the above descriptions. For example, the first collimating portion and the second collimating portion may also have other shapes. In the embodiment, shapes of the first collimating portion and the second collimating portion are not limited. In the embodiment, a combination of the collimating hole sets having different aperture sizes may be realized by adopting the relative movement between the first collimating portion and the second collimating portion, thereby not only achieving adjustment of different shapes of the radiation field at the focus, but also increasing the dose control range at the focus and improving the accuracy of the dose control. A multi-source focusing radiation therapy head is disclosed in the embodiment, including any one of the above collimating bodies. For example, in the embodiment, in a case where the shapes of the radiation field or a dose rate at the focus needs to be adjusted, a servo motor is started to drive the ball screw feed, and the relative movement between the first collimating portion and the second collimating portion is driven by the ball screw. In a case where a target collimating hole set on the first collimating portion is aligned with a target collimating hole set on the second collimating portion, the servo motor is turned off and the brake is kept in a braking state before the treatment may be started. The above is a further detailed description of the present disclosure in combination with the specific preferred embodiments, and it cannot be assumed that the specific embodiments of the present disclosure are limited to these descriptions. For an ordinary person skilled in the art to which the present disclosure pertains, a number of simple deductions or substitutions may be made without departing from the spirit, which will be considered as belonging to the protection scope of the present disclosure. |
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062427474 | summary | FIELD OF THE INVENTION The present invention pertains to an ion implantation apparatus for implanting ions into targets such as silicon wafers, and more particularly to a method and system for optimizing the operational parameters of a linear accelerator (linac) in such an apparatus. BACKGROUND OF THE INVENTION In an ion implantation apparatus having a conventional acceleration system, operational parameters regarding the acceleration of the ions in the beam can be easily obtained by analysis. For example, in an acceleration method which utilizes an electrostatic field, typical in most ion implantation apparatuses, the required voltage (V) of a power supply which is used to create the electrostatic field is simply obtained by the following equation (1) using the ionic valence value (n) of the desired ions and the desired energy (E) of the ions, typically measured in kilo-electron volts (keV). EQU V=E/n (1) When the electric field is applied in multiple stages, the sum of all of the fields can be made to be equal to the value V. However, in an ion implantation apparatus utilizing a radio frequency (RF) linear accelerator (linac), comprised of resonator modules each having an accelerating electrode, both the amplitude (in kilovolts (kV)) and the frequency (in Hertz (Hz)) of the accelerating electrode output signal must be determined as operating parameters of the resonator module. Moreover, when a multiple-stage RF linac is utilized, the phase difference (.PHI.) (in degrees(.degree. )) of each accelerating electrode output signal is included within the required operational parameters. When a multiple-stage RF linac is used, the amplitude, frequency and phase difference of the accelerating electrode output signals cannot be analytically determined using the incoming energy of the ions into the RF linac and the post-acceleration desired energy of the ions. This is because there are indefinite sets of solutions corresponding to the combination of required parameters. In addition, when magnets (such as a quadrupole magnet or an electromagnet) are used for controlling the lateral spread of an ion beam during or after acceleration, or when electrostatic lenses (such as electrostatic quadrupole electrodes) are used to provide a convergence/divergence effect on the beam, their operation parameters (e.g., electrical current or voltage) must be also determined. However, such magnetic or electrostatic operational parameters cannot be determined until the RF linac parameters are determined, because the optimum values for these factors are altered depending on the energy of the ions passing therethrough. In addition, the strength of the electric field of the RF linac affects the convergence/divergence of the magnet or electrostatic lens. Furthermore, even after the RF linac parameters (amplitude, frequency, and phase) are determined, the magnetic or electrostatic operational parameters cannot be analytically determined but are instead calculated step by step. As previously discussed, in an ion implantation apparatus in which ions are accelerated using an electrostatic voltage, acceleration parameters can be easily determined by analysis. Hence, if data such as an acceleration condition (the ionic valence value of ions) and a desired energy is entered by an operator or provided by a higher level computer, the necessary acceleration parameter (e.g., electrical current or voltage) can be calculated by a control device of the ion implantation apparatus and automatically determined by analytical solution of equations. FIG. 5 shows such a process for determining an electrostatic acceleration parameter. However, in the case of an implantation apparatus including an RF linac, the RF linac operational parameters (amplitude, frequency and phase) and the parameters of a convergence/divergence lens which controls the convergence/divergence of an ion beam cannot be analytically obtained. As shown in FIG. 6, a typical process for determining the linac operational parameters involves first selecting combinations of parameter values that have previously been found to optimize operation of the RF linac for a particular desired target energy level. The selection is based on acceleration conditions and a desired final energy value. If the selected combination of parameter values results in achievement of the target energy value, the selected combination of parameters is used without changes. If however, as is likely, the target energy value is not achieved using the selected combination of parameter values, the combination of parameter values that comes closest to achieving the target energy value is chosen to actually accelerate an ion beam. Then, by gradually changing the control parameters, a combination of parameters is found for obtaining a beam with the target energy. Through successive iterations, using trial-and-error operations that are necessary because changing one parameter affects the others, the parameters are adjusted gradually until an optimum combination of parameter values are found. However, the process as shown in FIG. 6 requires a very large amount of time and effort to arrive at the optimum combination of operational parameters. In addition, one cannot be sure that the obtained combination of parameters is the optimum combination. Moreover, the adjustment must be performed by an operator and hence, an automatic start-up and operation cannot be achieved for an ion beam with a new set of operating conditions. It is therefore a purpose of the present invention to provide quick and easy automatic calculation of RF linac operational parameters for an ion implantation apparatus. Another purpose of the present invention is to enable the generation of an ion beam having a desired energy level in a short period of time. Yet another purpose of the present invention is to enable operating parameters for a convergence/divergence lens in an ion implanter to be established with ease and in a short period of time. SUMMARY OF THE INVENTION The present invention provides an ion implantation apparatus which has an RF linear accelerator (linac) which produces ion energy of a desired value by accelerating or decelerating ions using a radio frequency (RF) field, and a control calculation device which automatically calculates at least one of the RF linac operational parameters, which are amplitude, frequency and phase. In particular, the control calculation device simulates the ion beam acceleration and deceleration based on numeric value calculation codes which are stored in advance therein and automatically calculates at least one of the RF linac operational parameters. The RF linac has one or more RF power supplies and one or more amplitude control devices for controlling the amplitude of the output of the RF power supplies. The control calculation device includes logic that uses stored numeric value calculation codes to calculate a numeric value of the RF amplitude. This value controls the one or more amplitude control devices, which control the output voltage amplitudes of the one or more RF power supplies. The RF linac has one or more RF power supplies and one or more phase control devices for controlling the phase of output of the RF power supplies. The control calculation device includes logic that uses the numeric value calculation codes to calculate a numeric value of the RF phase. This value controls the one or more phase control devices, which control the output voltage phases of the one or more RF power supplies. The RF linac has one or more RF power supplies and one or more frequency control devices for controlling the frequency of the output of the RF power supplies. The control calculation device includes logic that uses the numeric value calculation codes to calculate a numeric value of the RF. This value controls the one or more frequency control devices, which control the output voltage frequencies of the one or more RF power supplies. The RF linac has one or more RF resonators and one or more frequency control devices for controlling the resonance frequency of the RF resonators. The control calculation device includes logic that uses the numeric value calculation codes to calculate a numeric value of the RF frequency. This value controls the one or more frequency control devices, which control the resonance frequencies of the one or more RF resonators. The present inventions also provide an ion implantation apparatus which includes convergence/divergence lenses for efficiently transporting the ion beam by converging and diverging the ions in the beam, and a control calculation device that automatically calculates at least one of the parameters of the convergence/divergence lenses, which are electrical current and voltage. In the present invention, the control calculation device includes logic that simulates the ion beam acceleration and deceleration based on the numeric value calculation codes that are stored in advance therein, and automatically calculates parameters of the convergence/divergence lenses. The control calculation device of the present invention can provide a combination of RF linac operational parameters (amplitude, frequency and phase) so that the transmission efficiency of an ion beam through the linac is maximized using stored numeric value calculation codes. Furthermore, the control calculation device of the present inventions can also calculate the operational parameters of convergence/convergence lenses, which control conversion and diversion of an ion beam, using stored numeric value calculation codes. |
description | This application claims the benefit of U.S. Provisional Application No. 60/528,083, filed Dec. 9, 2003. 1. Technical Field The described invention relates generally to controlling dose uniformity during ion implantation. More particularly, the described invention is directed to controlling the uniformity and dose of a semiconductor wafer by using variable scan velocity in multiple scan directions and is particularly suited for low energy implant applications. 2. Related Art Ion implantation processes typically require a uniform and consistent dose or amount of ions to be implanted into a semiconductor wafer. Dose is generally a function of ion beam current density and time that the wafer spends in front of an ion beam. Current serial implanters provide an ion beam that is horizontally either an electrostatically scanned spot beam or a uniform ribbon beam. Serial implanters may also use a magnetically scanned spot beam, and a dual mechanically scanned (raster) spot beam. One conventional approach provides a horizontally uniform ion beam, and then mechanically moves the wafer at a constant velocity in the vertical direction. In another conventional approach, the wafer is moved vertically and the ion beam is moved back-and-forth across the wafer. Unfortunately, both of these approaches are problematic for the low energy market because the beam has to be manipulated, which requires continual tuning of the ion beam. As a result, the required implant time is increased and wafer throughput is decreased. One approach to address this situation is disclosed in U.S. Pat. No. 6,677,599 to Berrian. Under this approach, a wafer is translated at a non-uniform velocity through the ion beam as it is simultaneously rotated at a rotational velocity. A shortcoming of this device is that the constant rotation of the wafer introduces unnecessary complexity into attaining a uniform dose. Constant rotation also introduces to two other problems. First, maintaining constant tilt and wafer orientation is very difficult. In particular, the wafer holder needs to rotate around its axis for any tilted implant, which greatly complicates the mechanism. Second, continuous rotation of a product wafer has been shown to damage the product wafer a couple of different ways. First, fine scale structures on the wafer may not have sufficient structural integrity to withstand the centripetal acceleration, and, second, the rotation greatly adds to the kinetic energy when particles collide with the wafer surface and enhance the destructive potential of the particles. In view of the foregoing, an approach is desired for allowing the use of an at least partially un-tuned beam to be used to attain a uniform implant without the problems of the related art. The invention includes a system, method and program product for enhancing dose uniformity during ion implantation. The present invention is directed to allowing the use of an at least partially un-tuned ion beam to obtain a uniform implant by scanning the beam in multiple rotationally-fixed orientations (scan directions) of the target at variable scan velocities. The non-uniform scan velocities are dictated by a scan velocity profile that is generated based on the ion beam profile. The beam can be of any size, shape or tuning. A platen holding a wafer is rotated to a new desired rotationally-fixed orientation after a scan, and a subsequent scan occurs at the same scan velocity profile or a different scan velocity profile. This technique may be used independently or in conjunction with other uniformity approaches to achieve the required level of uniformity. A first aspect of the invention is directed to a method for conducting uniform dose ion implantation of a target with an ion beam, the method comprising the steps of: providing an ion beam; determining an ion beam profile of the ion beam; determining a scan velocity profile based on the ion beam profile, the scan velocity profile dictating a non-uniform scan velocity across the target to provide a uniform dose; implanting the target using the ion beam including varying a scan velocity according to the scan velocity profile; rotating the target from a rotationally-fixed orientation about a location substantially at a center of the target to a subsequent rotationally-fixed orientation; and repeating the implanting step. A second aspect of the invention is directed to an apparatus for conducting uniform dose ion implantation of a target with an ion beam, the apparatus comprising: a source of an ion beam for implanting the target, the ion beam having an ion beam profile; a target scan translator configured to move the target through the ion beam according to a scan velocity profile that is based on the ion beam profile, the scan velocity profile dictating a non-uniform scan velocity across the target; a target rotator configured to rotate the target from the rotationally-fixed orientation about a location substantially at a center of the target to a subsequent rotationally-fixed orientation between at least two implanting procedures; and a controller configured to operate the target scan translator and the target rotator to provide a substantially uniform dose of ions across the target. A third aspect of the invention is directed to a computer program product comprising a computer useable medium having computer readable program code embodied therein for controlling an ion implanter system to provide a substantially uniform dose to a target, the ion implanter system including a target translator configured to move the target through the ion beam and a target rotator configured to rotate the target about a location substantially at a center of the target, the program product comprising: program code configured to determine an ion beam profile of the ion beam; program code configured to determine a scan velocity profile based on the ion beam profile, the scan velocity profile dictating a non-uniform scan velocity across the target to be used by the target translator to provide a substantially uniform dose to the target; and program code configured to determine whether to rotate the target using the target rotator between ion implant procedures from a rotationally-fixed orientation about a location substantially at a center of the target to a subsequent rotationally-fixed orientation. The foregoing and other features of the invention will be apparent from the following more particular description of embodiments of the invention. Referring to the drawings, FIG. 1 illustrates an ion implanter system 10 for conducting uniform dose ion implantation of a target (i.e., wafer) with an ion beam. According to the invention, an ion beam 14 is scanned across a target 16 at non-uniform or variable scan velocity under the control of a processor 50. Ion implanter system 10 includes, inter alia, a source 12 of ion beam 14 for implanting a target 16 that is mounted on a platen 18, a target scan translator 30, a target rotator 40 and processor 50. Ion beam 14 may have any size or shape, and may be tuned or at least partially un-tuned according to the invention. However, the beam must have non-zero beam current at the position where the center of the target will be scanned. It is preferred, but not essential, that the beam is as wide as the target. If the beam is not as wide as the target, the number of orientations increases greatly. Ion beam 14 has an ion beam profile that indicates the ability of the ion beam to provide a uniform dose at various portions thereof. Ion beam profile may be one-dimensional or two-dimensional and may include, for example, current density across ion beam 14, and may be determined by processor 50 using a detector 60 such as a multi-pixel Faraday detector. More particularly, each scan path is discretized and ion beam 14 current is measured at each step in an embodiment of the present invention. The beam current is assumed to be stable or constant. Processor 50 is also configured to operate target scan translator 30 and target rotator 40 to provide a substantially uniform dose of ions across target 16, as will be described in more detail below. Target scan translator 30 is configured to move target 16 through ion beam 14 in a translating fashion, i.e., into and out of page of FIG. 1, according to a scan velocity profile that is based on the ion beam profile. It should be recognized that moving target 16 through ion beam 14 can include: translationally moving the target 16, moving ion beam 14 across target 16, or a combination of both movements. The scan velocity profile dictates a non-uniform scan velocity to accommodate the ion beam imperfections as evidenced by the ion beam profile. Target rotator 40 is configured to rotate target 16 from the rotationally-fixed orientation about a location substantially at a center of the target to a subsequent rotationally-fixed orientation between at least two implanting scans. That is, between implanting scans, the scan direction is varied by rotating target 16. Any number of scan directions, i.e., wafer orientations, may be used. FIG. 2 shows one example of the present invention where four scan directions are performed by rotating the wafer through orientations of 0°, 90°, 180°, and 270°. In this embodiment, each rotation is for about 90°. In one embodiment, one scan velocity profile can be used for all scan directions based on the ion beam profile. However, a specific scan velocity profile for each scan based on the ion beam profile may be utilized in other aspects of the present invention. With further regard to the scan velocity profile, in an alternative embodiment, the scan velocity profile may also be based on the rotationally-fixed orientation (scan direction) of the target. For instance, if the scan direction is not the first scan direction used, the amount of dose provided at the previous one or more scan directions can be considered to determine the new scan velocity profile, as will be described more fully below. Referring to FIG. 3, a flow diagram of the operational methodology of system 10 will now be described in conjunction with the structure of FIG. 1. In a first step S1, ion beam 14 is provided in a conventional fashion. In a second step S2, the ion beam profile of the ion beam is determined by processor 50 measuring ion beam 14 using detector 60. Both steps S1 and S2 occur before the target is scanned. In step S3, a scan velocity profile is determined based on the ion beam profile by processor 50 (FIG. 2). As noted above, the scan velocity profile dictates a non-uniform scan velocity across the target to provide a uniform dose, which determines the time that ion beam 14 remains on each portion of target 16 and accordingly the dose. Use of multiple scan directions and non-uniform scan velocity may be combined with various search routines. A search routine may be iterative and convergent for modifying velocity and re-evaluating sigma distribution across the entire wafer. The variable scan velocity may be found in a number of ways, including a multi-dimensional search or solution of a set of coupled equations. FIG. 4 shows a flow diagram of one embodiment for determining the scan velocity using a multi-dimensional search method. In a first step S101, a starting velocity profile is identified. Two examples of starting velocity profiles are a uniform velocity profile and a velocity profile that is proportional to the current in the beam profile, namely one that scans faster at positions corresponding to high beam currents and slower at positions corresponding to low beam currents. In step S102, the dose on the wafer at each position is computed for the velocity profile combined with the ion beam profile information. The standard deviation of the calculated dose is also computed and used to evaluate the performance of the velocity profile. In the next step S103, a determination is made as to whether the standard deviation meets the target criterion. If YES, the scan velocity profile is used to implant at step S104, i.e., step S4 of FIG. 3, described in more detail below. If NO, at step S105, a determination is made as to whether a number of allowed attempts to find a satisfactory velocity profile has been exceeded. If YES, then an error is indicated and processing stops at step S106. If NO at step S105, a new velocity profile is computed at step S107. This new velocity profile might be computed by making a systematic modification of the old profile, or might be computed by a textbook multi-dimensional search algorithm (such as downhill simplex). At an optional step S108, a determination is made as to whether the new velocity profile is acceptable. For example, the new velocity profile may by tested for “smoothness” in order to limit the velocity excursions and wear on mechanical components. A smooth, slowly varying velocity profile is desirable because it limits the amount of acceleration, jerk (which is the derivative of acceleration) and loading on mechanical components such as motors and bearings. The scan system has a limited ability to follow really erratic velocity profiles, which tends to increase wear. Acceptable profiles may also be tested for calculated uniformity. If the new velocity profile is deemed unacceptable (e.g., insufficiently smooth), i.e., NO at step S108, then it is corralled, at step S109, and then re-tested via repetitions of steps S102–S108. If the new velocity profile is deemed acceptable, i.e., YES at step S108, then processing proceeds to repeat steps S102–S108. These steps are continued until the entire scan velocity profile is optimized for the required standard deviation of the dose uniformity. Returning to FIG. 3, in step S4, target 16 is implanted using ion beam 14 including using a non-uniform or varying scan velocity, e.g., the velocity at which target translator 40 moves target 16, according to the scan velocity profile. In step S5, a determination is made as to whether a rotating of target 16 is required. In one preferred embodiment, this determination is simply ascertaining how many scan directions were specified by a user. However, other more complex determinations based on the dose previously applied may be implemented, if desired. If YES at step S5, then at step S6, target 16 is rotated from a rotationally-fixed orientation about a location substantially at a center of the target to a subsequent rotationally-fixed orientation, as shown in FIG. 2, to provide a new scan direction. If NO at step S5, then processing ends. Step S7 represents an optional step in which a determination as to whether to change the scan velocity profile is desired or necessary after rotating (step S5) to the subsequent rotationally-fixed orientation (scan direction). This determination can be triggered by any desired operational parameter of system 10 exceeding (equal, above or below) a threshold. In one example, beam instability as indicated by the average current density of the ion beam profile exceeding a threshold may be used. In an alternative embodiment, this determination can simply be user specified, e.g., use the new scan velocity profile every two rotations. If it is determined that the scan velocity profile is to be changed, i.e., YES at step S7, the scan velocity determining step S3 is repeated. In this case, the scan velocity profile may be different for a subsequent implanting step. If NO at step S7, or after a new scan velocity profile is determined (step S3), the implanting step S4 is repeated for the new rotationally-fixed orientation (scan direction). Processing may then continue to repeat steps S3–S7 for as many scan directions as desired. Conventional glitch recovery techniques may be employed where necessary. The above-described approach utilizing multiple scan directions and variable scan velocity may realize improved dose uniformity (for example, within a sigma <1% (not shown)) with an un-tuned or partially tuned beam while maintaining a high throughput of wafers. FIGS. 5A, 5B and 5C illustrate dose uniformities for various implanting methods. FIG. 5A shows a conventional single pass implant at a constant scan velocity. FIG. 5B shows a conventional four pass implant where each of the passes is scanned at a constant scan velocity. A four pass implant according to one embodiment of the present invention is shown in FIG. 5C where each of the passes is scanned at a variable scan velocity that is determined based on the detected ion beam profile. A comparison of FIGS. 5B and 5C illustrates the improved dose uniformity realized according to the present invention. The above-described approach may also be used independently or in conjunction with other uniformity approaches to achieve the required level of uniformity. In the previous discussion, it will be understood that the method steps discussed are performed by processor 50 executing instructions of a program product stored in memory. It is understood that the various devices, modules, mechanisms and systems described herein may be realized in hardware, software, or a combination of hardware and software, and may be compartmentalized other than as shown. They may be implemented by any type of computer system or other apparatus adapted for carrying out the methods described herein. A typical combination of hardware and software could be a general-purpose computer system with a computer program that, when loaded and executed, controls the computer system such that it carries out the methods described herein. Alternatively, a specific use computer, containing specialized hardware for carrying out one or more of the functional tasks of the invention could be utilized. The present invention can also be embedded in a computer program product, which comprises all the features enabling the implementation of the methods and functions described herein, and which—when loaded in a computer system—is able to carry out these methods and functions. Computer program, software program, program, program product, or software, in the present context mean any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after the following: (a) conversion to another language, code or notation; and/or (b) reproduction in a different material form. Variations of the methods, systems and apparatus as described above may be realized by one skilled in the art. Although the methods, apparatus and systems have been described relative to specific embodiments thereof, they are not so limited. Obviously many modifications and variations may become apparent in light of the above teachings. Many additional changes in the details, materials, and arrangement of the parts and algorithms, herein described and illustrated, can be made by those skilled in the art. Accordingly, it will be understood that the present invention is not to be limited to the embodiments disclosed herein, can include practices otherwise than specifically described, and are to be interpreted as broadly as allowed under the law. |
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047524391 | abstract | A gas cooled high temperature nuclear reactor utilizes an independent cooling system for the safety enclosure surrounding the reactor vessel. The cooling system comprises means for circulating cooling medium at least on the reactor side of a concrete safety enclosure shell and a separate closed cooling loop for circulation of separate cooling medium through a reservoir of the first cooling medium and to the outside of the entire nuclear reactor installation. |
abstract | A method of evaluating at least one quantity relating to the distortion of a nuclear fuel assembly, the method including the following steps: the nuclear fuel assembly is placed in a volume of water bounded by an upper free surface; a camera is placed outside the volume of water, above the free surface; at least one image of at least one lateral face of the nuclear fuel assembly is taken; the at least one image is analyzed graphically and the at least one quantity relating to the distortion of the nuclear fuel assembly is deduced therefrom. |
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summary | ||
claims | 1. Process for manufacturing a nuclear component via the method of chemical vapor deposition of an organometallic compound by direct liquid injection (DLI-MOCVD), the nuclear component being chosen from a nuclear fuel cladding, a spacer grid, a guide tube, a plate fuel and an absorber rod, the nuclear component comprising:i) a support containing a substrate based on a metal chosen from zirconium, titanium, vanadium, molybdenum or base alloys thereof and at least one protective layer;ii) said at least one protective layer coating said support and composed of a protective material comprising chromium which is a partially metastable chromium comprising a stable chromium crystalline phase comprising chromium of centered cubic crystallographic structure according to the Im-3m space group and a metastable chromium crystalline phase comprising chromium of centered cubic crystallographic structure according to the Pm-3n space group;the process comprising the following successive steps:a) vaporizing a mother solution containing a hydrocarbon-based solvent free of oxygen atoms and a precursor of bis(arene) type comprising chromium; the precursor having a decomposition temperature comprised between 300° C. and 600° C.;b) introducing the mother solution vaporized in step a) into a chemical vapor deposition reactor in which is located said support to be covered and the atmosphere of which is at a deposition temperature comprised between 300° C. and 450° C. and at a deposition pressure comprised between 13 Pa and 7000 Pa, which brings about the deposition of said at least one protective layer on said support. 2. Process for manufacturing a nuclear component according to claim 1, wherein the nuclear component further comprises a liner placed on the inner surface of said support, which is the surface of said support opposite to the medium that is external to the nuclear component. 3. Process for manufacturing a nuclear component according to claim 2, wherein the process further comprises, before step a), depositing the liner at a deposition temperature comprised between 200° C. and 400° C., onto the inner surface of said support by chemical vapor deposition of an organometallic compound (MOCVD) or DLI-MOCVD with, as precursor(s), a titanium amide and further a precursor comprising silicon, a precursor comprising aluminum and/or a liquid additive comprising nitrogen if the material of which the liner is composed comprises, respectively, silicon, aluminum and/or nitrogen. 4. The process for manufacturing a nuclear component according to claim 2, wherein the nuclear component comprises an inner volume and an inner protective layer which coats the inner surface of said support coated with the liner. 5. Process for manufacturing a nuclear component according to claim 1, wherein the mother solution further contains an additional precursor having a decomposition temperature comprised between 300° C. and 600°, a carbon incorporation inhibitor or a mixture thereof. 6. The process for manufacturing a nuclear component according to claim 5, wherein the additional precursor is at least one precursor of bis(arene) type comprising an addition element chosen from yttrium, aluminum, vanadium, niobium, molybdenum, tungsten, a precursor comprising aluminum or yttrium as addition elements, or mixtures thereof such that the protective material is doped with the addition element. 7. Process for manufacturing a nuclear component according to claim 1, wherein said at least one protective layer is an outer protective layer which coats the outer surface of said support which is the surface of said support facing the medium that is external to the nuclear component. 8. Process for manufacturing a nuclear component according to claim 1, wherein the process further comprises, after step b):c) performing on said at least one protective layer at least one step chosen from a subsequent treatment step of ionic or gaseous nitridation, ionic or gaseous silicidation, ionic or gaseous carbosilicidation, or ionic or gaseous nitridation followed by ionic or gaseous silicidation or carbosilicidation. 9. Process for manufacturing a nuclear component according to claim 1, wherein the precursor of bis(arene) type comprising chromium or the precursor of bis(arene) type comprising the addition element comprise, respectively, an element M which is chromium or the addition element; the element M being in oxidation state zero (M0) so as to have a precursor of bis(arene) type comprising the element M0. 10. The process for manufacturing a nuclear component according to claim 1, wherein the substrate is coated with an interposed layer placed between the substrate and the at least one protective layer. 11. The process for manufacturing a nuclear component according to claim 1, wherein the nuclear component comprises an inner volume and an inner protective layer which coats the inner surface of said support. |
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description | Referring now in detail to the figures of the drawings, which show embodiment examples that relate to spacers with longitudinal webs and transverse webs that form rectangular meshes, and first, particularly, to FIG. 1 thereof, there is seen a longitudinal web 1 and transverse webs 2, 3 and 4 crossing it. The webs form a left-hand mesh in which no spring has as yet been inserted, whereas in a right-hand mesh, a spring 5 protrudes out from the center of the transverse web 2. In this embodiment, a domed, resilient or sprung central part 6 merges at the top and the bottom through a convex curvature 7 into a respective upper end strip 8 and lower end strip 9. A center line of a fuel rod to be inserted in the web is designated by reference symbol Axe2x80x94A. In an operating position, the center line Axe2x80x94A is located in the center between the webs 2 and 4. A profiled section is seated parallel to the center line Axe2x80x94A, on each rim of the two end strips 8, 9 of the spring 5. The spring therefore has four profiled sections of which only an upper front profiled section 10 and a lower front profiled section 11 are visible in FIG. 1. Corresponding rear profiled sections 10xe2x80x2, 11xe2x80x2 are covered and are therefore not shown in the drawing. In addition, the longitudinal web 1 in the right-hand part of FIG. 1 likewise carries a spring. However, that spring protrudes into a mesh located behind the longitudinal web 1 so that FIG. 1 only shows those parts of that spring (otherwise covered) which protrude through openings 12, 13, 14, 15 or are visible through these openings. The visible parts of the (otherwise covered) spring are two end strips 16, 17 and profiled sections 18, 19, 20, 21 seated on their lateral rims. The openings 12, 13, 14, 15 are repeated in the longitudinal web in the left-hand part of FIG. 1. Each of the openings 12, 13, 14, 15 contains a slot-shaped opening part 22, 23, 24, 25 extending in the same direction (namely to the left) transverse to the center line Axe2x80x94A. The profiled sections 18, 19, 20, 21 are seated on ends of the opening parts 22, 23, 24, 25. These profiled sections touch lateral end edges 26, 27, 28, 29 of the slots 22, 23, 24, 25. Each opening part 22, 23, 24, 25 ends in an enlarged opening part 30, 31, 32, 33. In the right-hand part of FIG. 1 it may be seen that the profiled sections 18, 19, 20, 21, which protrude through the slot-shaped opening parts 22, 23, 24, 25 in the operating position of the corresponding spring, can be removed from the openings 12, 13, 14, 15 if they are displaced along the slot-shaped opening parts 22, 23, 24, 25 to the right as far as the enlarged opening parts 30, 31, 32, 33. This displaced position corresponds to an assembly position of the spring. The slot-shaped parts of the assembly openings 12, 13, 14, 15 have a length which practically corresponds to half a distance between the profiled rims of the springs (i.e. practically half the spring width). The enlarged cross-sectional areas 30, 31 therefore come to rest in the center between the end edges 26, 28 and 27, 29 of the slots. The idea of this dimensioning is clear from FIG. 2. When a fuel rod 35 is inserted into the mesh, it presses the resilient central part 6 of the spring 5, with the connected convex curvatures 7, 8, into enlarged cross-sectional openings or snap-in openings 36, 37, which are increased in such a way that their upper edge and lower edges protrude beyond upper and lower dimensions of the spring 5. Therefore, in this way, the convex curvatures 7, 8 are used in order to fix the spring 5 when it is loaded by a fuel rod 35 and presses the fuel rod onto corresponding holding elements (for example knobs or protuberances 38, 39 on a side of the mesh opposite to the spring). Although springs with a C-shape are preferred, other spring shapes, provided they produce the desired spring force, can be combined with the fastening according to the invention. This is shown in FIGS. 3 to 5 using a spring 40 with a hat-shaped or plate-shaped central part 41. FIG. 4, in particular, shows rims 42, 43, 44, 45 on two end parts 46, 47 connected to the central part 41. These rims carry profiled sections 48, 49, 50, 51 which are in contact with respective inner parts 53, 53xe2x80x2 on an inside surface 55 of a wall 56 (represented by interrupted lines). Outer parts 52, 52xe2x80x2 of these profiled sections 48, 49, 50, 51 protrude through the non-illustrated assembly opening and encompass its opening rim. These assembly openings 60, 61, 62, 63 are represented more precisely in FIG. 6. In that figure, end edges of slot-shaped opening parts 70, 71, 72, 73 are designated by reference numerals 65, 66, 67, 68. The profiled sections 48, 49, 50, 51 touch these end edges in the operating position of the spring. In this case, the slot-shaped opening parts 70, 71, 72, 73 do not extend at right angles to the center line of the fuel rod but instead at a certain angle, so the spring must be compressed when it has to be displaced from the operating position into the assembly position. This is only possible while the spring is not loaded by a fuel rod (see FIG. 2) so that, in the loaded condition, the spring is locked in the operating position. In this case as well, the slot-shaped opening parts 70, 71, 72, 73 end in enlarged cross-sectional areas 75, 76, 77, 78. Arrows 79 indicate the width of the springs (the distance between outer side edges of the profiled sections), which correspond to a corresponding width 79 in FIG. 4. A cross section through a different spring, corresponding to FIG. 5, is shown in FIG. 7. This spring is inserted through an enlarged opening area 12xe2x80x2 of an assembly opening provided in a web 1xe2x80x2 through the use of profiled rims of its end strips 8xe2x80x2. The spring is then displaced in the direction of an arrow 79xe2x80x2 along a slot-shaped part 22xe2x80x2 of the assembly opening, sufficiently far for it to butt onto an end edge 26xe2x80x2 of that slot-shaped part. Since the profiled rims determine the size of the opening area 12xe2x80x2, these rims are initially bent toward one another. In this way, upper profiled sections (or all four profiled sections under certain circumstances) can be inserted in the common opening area 12xe2x80x2. In addition, this provides an improvement of a contact surface, through the use of which inner profiled section parts 53a are supported on an inner surface 2xe2x80x2 of the web. Whereas an outer profiled section part 53b encompasses an edge of the web 1xe2x80x2 at a rim of the slot 22xe2x80x2 which is only above and below the plane of the drawing, another rim 53c carries a protuberance which, in this case, is configured in the shape of a barb. In this way, the spring is locked in a snap-in opening 23xe2x80x2 of the web as soon as the operating position is taken up. In an embodiment example shown in FIG. 8, a central part 81 of a spring 80 likewise merges into end strips which extend approximately parallel to the center line of the fuel rod and which have lateral rims 82, 83, 84, 85 that are bent away from the fuel rod and pass through corresponding assembly openings 86, 87. Outer profiled section parts 91, 92, 93, 94, which protrude on the back of a web are, in this case (in a manner similar to FIG. 5), again bent around and spread in order to encompass edges of the openings 86, 87 with a larger surface. However, as a departure from FIGS. 1 to 7, only two slot-shaped opening parts are provided in this case. The upper slot-shaped opening part 86 is associated with the upper profiled section pair 91, 92 and the lower opening part 87 is associated with the lower profiled section pair 93, 94. Enlarged cross-sectional areas 88, 89 connected to the opening parts 86, 87 are located, in this embodiment example, at a position at which one longitudinal wall is crossed by a transverse wall. The spring is therefore inserted in the corresponding webs before the spacer is welded. Although this prevents a damaged spring, for example, from being subsequently changed, it reliably prevents a spring from becoming unintentionally loose if a rod is removed from the fuel assembly during inspection work. In order to fix the spring in the operating position, each end strip 95, 96 carries a locking knob or protuberance 97, 98 which engages in a corresponding locking window 97xe2x80x2, 98xe2x80x2 in the web. The spring can therefore only be removed from the operating position if the corresponding end strips are bent sufficiently far away from the web. In addition, the end strips of FIG. 8 carry further knobs or protuberances 99, 99xe2x80x2 which point in the direction toward the resilient central part and act as a stop that limits the deflection of the resilient central part during loading of the spring. This can prevent the spring from being overstrained and damaged when the corresponding fuel rod is inserted in the mesh. Generally speaking, it suffices if the outer profiled section parts, on the rims of the end strips, which are bent away from the fuel rod and protrude through the assembly openings, are only profiled in one direction, i.e. are configured as support webs which pass through the web in the assembly opening approximately at right angles and extend approximately parallel to the center line of the fuel rod. A bottom of such a first spring 100 is shown on the left in FIG. 9. A central part 101 is substantially covered by end strips 102 and 103 with snap-in knobs or protuberances 104, 105. Four profiled sections 106, 107, 108, 109, which form lateral rims of the end strips 102 and 103 as flat support webs, can be seen. A top of a second spring 110 with a central part 111 and end strips 112, 113 that are covered (and therefore only indicated by interrupted lines) are shown on the right. In this position of the two springs 100 and 110, the two springs are symmetrically placed relative to one another to the extent that the bottom of the first spring 100 points to the bottom of the second spring 110. FIG. 10 shows two parallel webs 120, 121 of the spacer. The spring 100 is inserted from the left into the web 120 and the spring 110 is inserted from the right into the web 121. Profiled sections 106, 116 and 107, 117 on the rims of the two springs 100, 110 differ somewhat in this case. One outer profiled section part 123 of the profiled section 106, which is initially pushed through a non-illustrated assembly opening and protrudes through a slot of the web 120, has a recess 124 with a width b, which is not necessary for the profiled section 116. The width b corresponds approximately to the width of the profiled section 116 at a position where this profiled section 116 merges into an end strip 112. In addition, the spring 110 also differs from the spring 100, as is shown in FIG. 9, by the fact that inner surfaces of web-type rims 116, 118 of the spring 110 are at a distance from each other which is equal to or slightly larger than a distance axe2x80x2 between outer surfaces of web-type rims 106, 108 of the spring 100. The following is achieved, as is shown in FIG. 9, by this profiling: The two springs are already shown in such a way that their central parts point to opposite sides. If the spring 100 is, for example, displaced to the right, this makes it possible for the rims of the spring 100 to be inserted from the left into the corresponding rims of the spring 110, which are rims that point to the left. The two springs can therefore be simultaneously fastened to a common wall in such a way that their end strips are opposite to one another, as is shown in FIG. 11 through the use of a wall 130. The spring 100 is therefore inserted from the left, corresponding to an arrow 131, and the spring 110 is inserted from the right, corresponding an arrow 132, into a widened opening in the wall 130. The springs are displaced in the opening until, at the upper end strips 102 and 112, the profiled sections 106 and 116 of both springs, or the profiled sections 108 and 118, respectively, form a mutually engaging profiled section pair. At the lower end strips 103, 113, a profiled section pair is correspondingly formed from the profiled sections 107 and 117 and a second pair of mutually engaging profiled sections is formed from the profiled sections 109, 119. FIG. 12 shows the wall 130 with an enlarged cross-sectional area before the springs 100 and 110 are inserted in directions corresponding to the arrows 131 and 132 into corresponding assembly openings 134, through the use of their profiled section parts. The profiled sections of the two springs then finally engage in one another and the spring pair can then be displaced laterally along the edge of a slot-shaped opening part into the operating position. FIG. 13 shows a corresponding cross section of the fully assembled spring pair. The cross-sectional plane selected for FIG. 13 is indicated by numerals XIIIxe2x80x94XIII in FIG. 11. FIG. 14 shows the bottom of a spring 150 which represents a combination of the two-springs 100 and 110 from FIG. 9 to the extent that lateral rims 151, 152 of an upper end strip 150xe2x80x2 are formed corresponding to the rims 106, 108 of the end strip 102 of the spring 100. Corresponding lower rims 153, 154 are formed corresponding to the lower rims 117, 119 of the spring 110. If the spring 150 is pivoted about its transverse center line CC, the left-hand spring 150 of FIG. 14 becomes a right-hand spring 160. These two springs 150, 160 can now be combined to form a spring pair in the same manner as has been presented in FIGS. 12 and 13. This embodiment, therefore, only necessitates a single spring type. In a spring 170 of FIGS. 15 and 16, a right-hand upper rim 173 of an upper end strip 171 and a left-hand lower rim 174 of a lower end strip 172 are formed corresponding to the web-type rims of the spring 100. However, a left-hand upper rim 176 and a right-hand lower rim differ from the rim of the spring 100 to the extent that outer profiled section parts 176xe2x80x2, 177xe2x80x2 protruding beyond the web are bent outward over the rim of the slot-shaped opening part. The spring 170 therefore presents a combination of the spring 150 and the spring shown in FIG. 8. In addition, the profiled sections 174, 176 of the spring 170 can also be combined to provide a single profiled section which can be used for all four rims 181, 182, 183, 184 of the spring, as is shown by a spring 180 of FIG. 17. In this embodiment, one profiled section part 185 corresponds to the profiled section part 176xe2x80x2 and another profiled section part 186 corresponds to the profiled section part 174. It may therefore be seen that the fastening according to the invention opens many variation possibilities. In a spacer, such as is shown as a portion of a pressurized water reactor, for example, in FIG. 18, webs 200, 201, 202, 203, etc. generally form square meshes in which two adjacent mesh sides each carry a spring in the center protruding into the mesh. The spring presses the fuel rod of this mesh (the fuel rods are omitted for the sake of clarity) against opposite knobs or protuberances 205. Two individual knobs or protuberances are usually located opposite a spring. The knobs or protuberances are disposed one above the other and respectively above and below the plane in which the spring presses against the fuel rod. In general, each two adjacent meshes (for example meshes 206, 207) form a pair. The springs (for example the springs 110 and 100) which protrude into the meshes of a pair from a common wall separating the meshes of the pair, can be fastened as shown in FIGS. 10 to 17. Since pressurized water fuel assemblies also have some meshes which contain a guide tube 204 on which the spacer is fastened, instead of a fuel rod, there can be deviations in the configuration in pairs of the meshes, so that unpaired springs (for example the spring 5) can also be necessary. Similar relationships can also be caused by water pipes, such as are used in many boiling water fuel assemblies, replacing some fuel rods. FIG. 19 shows a longitudinal section through a part of the meshes 206 and 207 with springs 210, 110 and 100 supported on the webs 200 and 203. An assembly opening can be recognized in a wall 200. The assembly opening is necessary for inserting the spring 210 or a spring pair of which, apart from the first spring 210, only an outer profiled section part is visible, which is respectively formed on side rims of end strips of a second spring. The assembly opening, which in this case is formed of two slot-shaped opening parts 220 and 230, has a widened opening area 221 which is laterally offset relative to the position in which the spring 210 (or the spring pair mentioned above) is located. This widened opening area is advantageously applied at the position of the web at which this web crosses another web 203 in the finally assembled fuel assembly. Therefore, this widened opening area is blocked when the webs are joined together to form a grid-shaped spacer after the insertion of the springs. In accordance with FIGS. 12 and 13, the spring 210 is inserted through the use of the profiled section parts of its end strips from the front of the web shown in FIG. 19. Only inner profiled section parts 250, 251, 252, 253 of the spring 210 remain in the mesh while outer profiled section parts, which are not visible in FIG. 19, protrude into the adjacent mesh. Outer profiled section parts 240, 241, 242, 243 of the other spring are correspondingly pushed from the adjacent mesh (i.e. the back of the wall 200) through an opening area 220xe2x80x3 and the two springs are joined together in such a way that one profiled section pair 240, 250 or 241, 251 or 242, 252 or 243, 253 results in each case. If the widened opening area is to be used to insert corresponding springs in both a position D and in a position E, slot-shaped opening parts (220, 220xe2x80x2, 230, 230xe2x80x2) symmetrically emerge from this opening area toward both sides. These slot-shaped opening parts have edges 221, 222 and 231, 232 at the top and at the bottom, which act as a guide for the profiled section pairs when these profiled section pairs are displaced laterally from the assembly position into the operating position D. In this operating position, two profiled section pairs, namely the profiled section pair 240, 250 and the profiled section pair 241, 251 then touch the end edges 225, 235, located one above the other, of the slot-shaped opening parts 220, 230. Apart from the extremely small material requirement for the fastening of the spring and the great freedom of choice for the shape of the spring itself, the invention has the great advantage of permitting two springs protruding into adjacent meshes to be seated in the same assembly opening in the center of a mesh wall. The principle which is used can be briefly stated by using the spring 5 of FIG. 18 as an example: The spring, of which only an upper end 301 is visible in FIG. 18, has one rim 302, 303 for each of the sides at this upper end. That rim is bent out of the mesh 206 around the center line of the fuel assembly in such a way that it penetrates through an assembly opening 304 into the web 201. These two rims (302, 303) each carry a profiled section which approximately form-lockingly encompasses one edge of the assembly opening 304. The lower end of the spring also has one rim that is correspondingly bent outward on both sides with a profiled section form-lockingly encompassing an edge of the assembly opening. As is shown in the figures, generally each spring (FIGS. 1 through 8) or each pair of springs (FIGS. 11 through 19) is associated with one assembly opening area and at least one snap-in opening in a web. The snap-in opening (e.g. 97xe2x80x2 or 98xe2x80x2 in FIG. 8 and the opening for the snap-in knob or protuberence 98 or 105 in FIG. 10) may be separated from the assembly opening area, but it may as well be integrated into that assembly opening area, especially in the enlarged parts of that area. That is shown in FIG. 1, where the convex curvature 7 snaps in the enlarged part 30 of the assembly opening area, or in FIG. 6, where a concave protrusion 40xe2x80x2 (FIG. 3) of spring 40 snaps in the enlarged part 75. Each assembly opening area is formed of several parts which may be joined into one window or separated from each other. In FIG. 1, for instance, the assembly opening area is formed of four enlarged opening parts 30, 31, 32, 33 and four slot-shaped opening parts 22, 23, 24, 25, each slot-shaped opening part ending in an enlarged opening part. On the other hand, FIG. 8 shows only two slot-shaped opening parts 86, 87 and only two enlarged opening parts (enlarged cross-sectional areas 88, 89) forming one assembly opening area. |
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claims | 1. A method of evaluating the performance of a relief pitcher in the late innings of a baseball game in which the pitcher inherits at least one player on base, the method comprising the steps of establishing the number of runs Ri scored by such inherited runners; establishing the number of batters B faced in such innings; evaluating the Relief Quotient “RQ”, where: RQ = k ( Ri + E B ) n where k is first a predetermined constant selected to scale the RQ to a desired range of magnitudes, n is a second predetermined constant that may be positive or negative and E is a parameter that may be an integer or equal to 0 ; andstoring RQ in a tangible medium for subsequent use. 2. A method as defined in claim 1, wherein the runs Ri are modified or weighed by at least one factor reflecting a condition in the baseball game at the time that the relief pitcher is brought into the game. 3. A method as defined in claim 2, wherein the runs Ri are modified by a plurality of weighted factors. 4. A method as defined in claim 2, wherein said factor is a function of the number of the inning. 5. A method as defined in claim 4, wherein said factor increases for each subsequent inning. 6. A method as defined in claim 2, wherein said factor is a function of the number of outs. 7. A method as defined in claim 6, wherein said factor increases as the game moves through the innings. 8. A method as defined in claim 6, wherein said factor increases with the number of outs. 9. A method as defined in claim 2, wherein said factor is a function of the base on which the inherited runner is on. 10. A method as defined in claim 9, wherein said factor decreases as the base number increases. 11. A method as defined in claim 1, wherein a constant “k” is selected to provide an RQ in the range of 1–10. 12. A method as defined in claim 1, wherein said RQ is computed on the basis of a pitcher's performance within at least a part of one season. 13. A method as defined in claim 1, wherein said RQ is compiled on a pitcher's performance over a lifetime of pitching. 14. A method as defined in claim 1, wherein the RQ is compiled as follows: RQ = { { k × [ Fi [ ( k1 × R1 ) + ( k2 × R2 ) + ( k3 × R3 ) ] + F0 [ ( k1 × R1 ) + ( k2 × R2 ) + ( k3 × R3 ) ] + Fi [ ( k1 × R1 ) + ( k2 × R2 ) + ( k3 × R3 ) ] + F1 [ ( k1 × R1 ) + ( k2 × R2 ) + ( k3 × R3 ) ] + Fi [ ( k1 × R1 ) + ( k2 × R2 ) + ( k3 × R3 ) ] + F2 [ ( k1 × R1 ) + ( k2 × R2 ) + ( k3 × R3 ) ] ] + E } ÷ B } n ,wherein k is a scaling factor;k1, k2 and k3 are all base scaling factors;Fi is the Inning Factor;F0, F1 and F2 are the “No. of Out” Factors;Ri, R2 and R3 are Base Factors;n is a predetermined constant that may be positive or negative;E is an arbitrary factor for use particularly when “n” is a negative number; andB is the total number of batters faced by the pitcher. 15. A method as defined in claim 1, wherein n is positive. 16. A method as defined in claim 1, wherein n is negative. 17. An apparatus for evaluating the performance of a relief pitcher in the final innings of a baseball game in which the pitcher inherits at least one player on base, comprising:means for establishing the number of runs Ri scored by such inherited runner;means for establishing the number of batters B faced in such innings;means for evaluating the Relief Quotient “RQ”, where: RQ = k ( Ri + E B ) n ,and k is first a predetermined constant selected to scale the RQ to a desired range of magnitudes and n is a second predetermined constant; andmeans for storing RQ in a tangible medium for subsequent use. 18. An apparatus as defined in claim 17, wherein said evaluation means comprises a computer programmed to perform the required computations when the number of runs (Ri) number of batters faced (B) are entered. 19. An apparatus as defined in claim 17, wherein n is positive. 20. An apparatus as defined in claim 17, wherein n is negative. 21. A device for evaluating or comparing the performance or efficiency of a relief pitcher in the final innings of a baseball game in which the pitcher inherits at least one player on base, the device comprising means for providing a quantity defined as follows:RQ=k*((Ri+E)/B)**n, where Ri is equal to the number of runs scored by the inherited runners, B is the number of batters faced by the pitcher and k is a first predetermined constant selected to scale the RQ to a desired range of magnitudes and n is a second predetermined constant, said quantity being storable in a tangible medium for subsequent use. 22. A device as defined in claim 21, wherein the RQ is compiled as follows: RQ = { { k × [ Fi [ ( k1 × R1 ) + ( k2 × R2 ) + ( k3 × R3 ) ] + F0 [ ( k1 × R1 ) + ( k2 × R2 ) + ( k3 × R3 ) ] + Fi [ ( k1 × R1 ) + ( k2 × R2 ) + ( k3 × R3 ) ] + F1 [ ( k1 × R1 ) + ( k2 × R2 ) + ( k3 × R3 ) ] + Fi [ ( k1 × R1 ) + ( k2 × R2 ) + ( k3 × R3 ) ] + F2 [ ( k1 × R1 ) + ( k2 × R2 ) + ( k3 × R3 ) ] ] + E } ÷ B } n ,wherein k is a scaling factor;k1, k2 and k3 are all base scaling factors;Fi is the Inning Factor;F0, F1 and F2 are the “No. of Out” Factors;R1, R2 and R3 are Base Factors;n is a predetermined constant that may be positive or negative;E is an arbitrary factor for use particularly when “n” is a negative number; andB is the total number of batters faced by the pitcher. 23. A device as defined in claim 21, wherein k is selected to provide an RQ in the range of 1–10. 24. A device as defined in claim 21, wherein said RQ is computed on the basis of a pitcher's performance within at least a part of one season. 25. A device as defined in claim 21, wherein said RQ is compiled on a pitcher's performance over a lifetime of pitching. 26. A device as defined in claim 21, wherein n is positive. 27. A device as defined in claim 21, wherein n is negative. 28. A method of evaluating a performance measure of a relief pitcher in a baseball game, wherein same relief pitcher inherits at least one player on base upon entering the game, the method comprising:a first step of establishing the number of runs Ri scored by such inherited runners;a second step of establishing the number of batters B faced in such innings;a third step of calculating a Relief Quotient “RQ”: RQ = k ( Ri + E B ) n ,wherein k is first a predetermined constant selected to scale the RQ relative to a desired range of magnitudes suitable for easy comparison, and n is a second predetermined constant selected from a group including at least one of +1 and −1, and E is a parameter that may be an integer or equal to 0; andstoring RQ in a tangible medium for subsequent use. 29. A method of calculating a performance measure of a relief pitcher in a baseball game, wherein said relief pitcher inherits at least one player on base upon entering the game, the method comprising:a first step of establishing the number of runs Ri scored by such inherited runners;a second step of establishing the number of batters B faced in such innings;a third step of calculating a Relief Quotient “RQ”: RQ = k ( Ri + E B ) n ,wherein k is first a predetermined constant selected to scale the RQ relative to a desired range of magnitudes suitable for easy comparison, and n is a second predetermined constant selected from a group including at least one of +1 and −1, and E is a parameter that may be an integer or equal to 0; andstoring RQ in a tangible medium for subsequent use. 30. A method of calculating a performance measure of a designated relief pitcher in a selected baseball game relative to a calculated average of a plurality of relief pitchers in a plurality of baseball games, wherein each said relief pitcher inherits at least one player on base upon entering the game, the method comprising:a first step of monitoring and recording a performance of said plurality of relief pitchers in said plurality of baseball games wherein said step of recordation includes the recordation, for each relief pitcher, of the number of runs Ri scored by such inherited runners and the recordation of the number of batters B faced in all such innings;a second step of calculating and recording a Relief Quotient “RQ” as a performance measure for each of said plurality of relief pitchers in an accessible database in accordance with the following equation: RQ = k ( Ri + E B ) n ,wherein k is first a predetermined constant selected to scale the RQ relative to a desired range of magnitudes suitable for easy comparison, and n is a second predetermined constant selected from a group including at least one of +1 and −1, and E is a parameter that may be an integer or equal to 0;a third step of calculating and recording an average Relief Quotient and a best possible Relief Quotient of said plurality of relief pitchers in said accessible database;a fourth step of monitoring and recording a performance of said designated relief pitcher in said selected baseball game;a fifth step of calculating and recording a Relief Quotient “RQ” of said designated relief pitcher in said database according to said equation;a sixth step of comparing said Relief Quotient from said designated relief pitcher to at least one of said average Relief Quotient and said best possible Relief Quotient to evaluate said performance of said designated relief pitcher; andstoring RQ in a tangible medium for subsequent use in at least one of said third through sixth steps. |
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059784326 | claims | 1. A dispersion fuel, comprising 30-55 vol % of spherical particles of an alloy dispersed in a nonfissionable matrix, wherein the alloy is selected from the group consisting of (1) uranium and 4-9 wt % Q and (2) uranium, 4-9 wt % Q and 0.1-4 wt % X, wherein Q is selected from the group consisting of Mo, Nb and Zr; and X is selected from the group consisting of Mo, Nb, Zr, Ru, Pt, Si, Ir, Pd, W and Ta, with the proviso that Q.noteq.X, and the uranium is present in a meta-stable .gamma.-U phase. 2. A process of manufacturing spherical particles of an alloy selected from the group consisting of (1) uranium and 4-9 wt % Q and (2) uranium, 4-9 wt % Q and 0.1-4 wt % X, wherein Q is selected from the group consisting of Mo, Nb and Zr; and X is selected from the group consisting of Mo, Nb, Zr, Ru, Pt, Si, Ir, Pd, W and Ta, with the proviso that Q.noteq.X, the process comprising providing uranium and alloying metals Q and optionally X in an atomizing chamber having a vacuum above 10.sup.-3 torr; melting the uranium and the alloying metals to produce an alloy melt; forming melt droplets of the alloy melt; and cooling the melt droplets at a cooling rate of above 10.sup.4 .degree. C./sec to produce spherical particles of the alloy. |
042886961 | summary | BACKGROUND OF THE INVENTION This invention relates to pulsed neutron well logging and more particularly to means for controlling the neutron output of a neutron generator tube used in pulsed neutron well logging. In recent years pulsed neutron well logging has become a commercially important well logging technique. Pulsed neutron techniques have been utilized for measuring the thermal neutron lifetime or thermal neutron decay time of earth formations in the vicinity of a well borehole, for making activation analyses of elemental constituents of the earth formations in the vicinity of the well borehole, for making porosity measurements of the earth formations in the vicinity of the well borehole and for making inelastic neutron scattering measurements for fast neutrons. In each of these well logging techniques the pulsed neutron source used to generate neutron pulses for the physical measurements has typically been an evacuated tube, deuterium-tritium accelerator type source. Such sealed off or evacuated tube neutron sources generally comprise an outer envelope of glass, metal or some other vacuum encapsulation material, such as ceramic, which houses therein the elements of the neutron generator tube. The tube elements generally comprise a target which is electrically insulated at a high voltage potential, a source of ions which may be accelerated onto the target by its high voltage potential and a pressure regulator or replenisher element which may be used to stabilize or or control the amount of pressure of gas within the evacuated outer envelope. Gas pressures of about 10.sup.-2 mm Hg. are typical for the operation of these tubes. The replenisher or pressure regulator of neutron generator tubes generally comprises a heater element which is surrounded by a surface which is capable of absorbing or emitting gas molecules of the gas filling the evacuated tube envelope as a function of its temperature. The capability of such a surface for emitting or absorbing gases in the tube envelope is controlled by the temperature of a heating element associated with it. When the heating element is elevated in temperature, the surrounding gas impregnated surface is encouraged to dispel absorbed gases by thermal emission. When the heating element is cooled, the surrounding surfaces associated with it are encouraged to absorb gases from the atmosphere inside the evacuated tube envelope. The amount of gas present in the tube envelope controls the amount of gas present in the ion source and hence, the capability of the ion source to produce positively charged ions of gas for acceleration onto the target material. In a typical neutron generator tube operation, the gas present in the evacuated envelope may be either deuterium gas or a mixture of deuterium and tritium gas. The target material is impregnated with tritium. Thus when deuterium ions are formed in the ion source and accelerated onto the target by its high voltage potential, the electrostatic Coulomb repulsion between the ions being accelerated and the nuclei of the tritium atoms is overcome and nuclear fusion takes place. This produces the unstable isotope helium 5 which immediately decays by the emission of an approximately 14 MEV monoenergetic neutron characteristic of this decay. A problem which has been associated with the use of such neutron generator tubes in well logging has been that the output of the neutron generator falls off as a function of time as the tritium in the target material is effectively used up by the nuclear reactions and by heating of the target. Also high voltage power supply voltage variations, replenisher heater current variations and ion source emission capability can cause neutron output to vary. For most well logging operations it is highly desirable that during a given logging run the neutron output of the tube remain constant and also as high as possible. High output is desirable to promote the nuclear interactions sought to be measured by the well logging technique in use. Consistency of the neutron output is desirable to promote measurement consistency and to avoid systematic errors. BRIEF DESCRIPTION OF THE INVENTION The neutron output of a neutron generator tube is a function of the target current of the tube. The target current, in turn, is a function of the target high voltage, the ion source voltage and the replenisher heater current. In the present invention, the target high voltage is at a fixed value. The ion source voltage is pulsed at a given repetition rate and pulse width. By varying the replenisher heater current and hence its heater element temperature, the average neutron output of the tube is controlled. In a preferred embodiment of the present invention, the target beam current is monitored, converted to a voltage signal and compared to a reference voltage. An error voltage developed from this comparison is used to control the replenisher current in such a manner that the replenisher current is automatically adjusted to maintain a constant value of the average target beam current corresponding to the reference voltage. A circuit for accomplishing this is provided which may be described as a series regulation replenisher current control circuit. Such a circuit may be used to vary the replenisher heater current or even turn off the replenisher current completely. The circuit embodiments of the present invention provide advantages over prior art control circuits for controlling neutron generator tubes in that improved regulation of the replenisher current is accomplished and a relative simple circuit using few parts is required for this. The replenisher current regulating circuit of the present invention also has a smaller power consumption than those known in the prior art and is capable of operating at temperatures of up to 200.degree. C. An additional feature of the control circircuitry of the present invention is the remote turn on or off capability of the replenisher heater current with relatively lower power COSMOS logic level voltages. The foregoing as well as other features and advantages of the present invention are described with particularly in the appended claims. The invention is best understood by reference to the following detailed description thereof when taken in conjunction with the accompanying drawings in which: |
description | The present invention contains subject matter related to Japanese Patent Application No. 2005-115937, filed in the Japanese Patent Office on Apr. 13, 2005 and Japanese Patent Application No. 2005-172315 filed in the Japanese Patent Office on Jun. 13, 2005, the entire contents of which are incorporated herein by reference. This invention relates to a working apparatus for doing works in a lower part of the inside of a nuclear reactor or the like and a working method of operating such an apparatus. Intra-nuclear-reactor working apparatus are generally used for intra-reactor operations such as inspections, examinations and preventive maintenances of the inner surface of nuclear reactor pressure vessels (RPVs) and intra-reactor structures. Particularly, when the weld line found in a lower part of the shroud support plate of a lower part of a boiling water nuclear reactor is the target of operation, it is difficult for the intra-nuclear-reactor working apparatus to get to the weld line and the operation faces various problems such as a limited working space and a long working time because it is difficult to access the target that is located in a very narrow area. Various intra-nuclear-reactor working apparatus have been proposed to carry out such an operation in a short period of time and secure a larger working space at a place having access difficulties. Firstly, an intra-nuclear-reactor working apparatus comprising a remotely operated vehicle (ROV) to be used in water that is equipped with a thruster for moving back and forth and for turning, a thruster for moving up and down and for moving sideways and an underwater camera is known (See, inter alia, Japanese Patent Application Laid-Open Publication No. Hei 11-14784, the entire contents of which being incorporated herein by reference). The apparatus disclosed in the cited reference is provided with an arm mechanism that can be turned and an inspection means selected from an ultrasonic inspection means, a radiation-resistance television camera, an infrared camera and so on is replaceably fitted to the front end of the mechanism. In this known apparatus, an X-Y scanner mechanism is arranged at the front end of the arm mechanism and any of a various inspection means is fitted to the scanner mechanism. For example, the arm mechanism and the selected inspection means are conveyed to the site of inspection by means of the thrusters of the underwater ROV and the X-Y scanner is pressed near the target of inspection and operated to scan the target by the selected inspection means, utilizing the degree of freedom of operation of the X-Y scanner. Secondly, a vehicle type mobile body designed to be used as intra-nuclear-reactor working apparatus as described below is known (See Japanese Patent Application Laid-Open Publication No. 2001-296385, the entire contents of which being incorporated herein by reference). This apparatus has a plurality of wheeled arms (cylinder rods) to be extended under the shroud support plate toward the RPV and the shroud support to make the apparatus itself to be preliminarily anchored there. Then, thrusters or the wheels that the mobile body is provided with are driven to move the apparatus to the working site along the periphery. The pressure being applied to the cylinder rods is raised there in order to securely anchor the apparatus. The apparatus is held in position by the wheels that are pressed by unfolding the work reaction force exerted by the object of work, in other words, the apparatus can hold a large work reaction force. Additionally, it is possible to accurately position the apparatus in a peripheral direction so that the apparatus can be highly reliable in repeated positioning by driving the wheels to travel and move. VT (visual testing) apparatus realized by mounting an inspection camera on a swimming type vehicle and UT (ultrasonic testing) apparatus realized by combining a swimming type vehicle and an arm to mount a UT probe for the purpose of inspecting weld lines in water located under the shroud support plate in a lower part of the core are known. It is possible to inspect a broad area in a short period of time in order to efficiently perform an assigned work by using such a swimming type vehicle and auxiliary mechanisms such as arms, because of their mobility and flexibility. However, preventive maintenance works and welding works involving brush polishing, water washing, water jet peening and/or laser peening encounter a large reaction force in the work, and hence it is difficult to carry out the work by using a swimming type vehicle for conveying objects, positioning itself and holding the position. Additionally, it is difficult for such a swimming type vehicle to move accurately and position itself to give rise to a difficulty in repeated positioning. On the other hand, a system for unfolding traveling wheels toward the inner wall of a pressure vessel and a shroud support, anchoring itself to a given position and driving thrusters or wheels to move horizontally, can utilize a large reaction force in the work to support itself and move and position itself accurately. However, when such a system is driven to travel by means of wheels in a peripheral direction of the shroud or the RPV, it can be vertically displaced. It is difficult to prevent or suppress such a vertical displacement. In view of the above-identified problems of the prior art, it is therefore an object of the present invention to provide a working apparatus and a working method that are adapted to move over a broad range within a short period of time with a limited number of setting operations, withstand a large reaction force and easily position itself repeatedly, moving along a structure in water and positioning itself. In order to attain the object, according to an aspect of the present invention, a working apparatus for doing works below a structure is provided. The apparatus comprises: a working equipment for doing works; a folding/unfolding mechanism that can be folded when moving the working equipment and unfolded when doing a work; a conveyance mechanism for conveying the working equipment and the folding/unfolding mechanism to the site of the work; a pressing mechanism for pressing the working equipment against the structure; and a traveling mechanism including wheels for traveling under and along the structure and positioning the apparatus. According to another aspect of the present invention, a working apparatus for doing works on a structure in water is provided. The apparatus comprises: a main body casing including a ballast tank; a working equipment arranged at an upper part of the main body casing so as to be able to project outward by way of a drive mechanism and adapted to do various works on the structure; a float arranged at an upper part of the main body casing so as to be able to project outward by way of a drive mechanism; and wheels arranged at outside of the working equipment and the float and adapted to abut the structure so as to turn the working equipment and the float. According to another aspect of the present invention, a working method for doing works under a structure is provided. The method comprises: conveying a working equipment and a folding/unfolding mechanism to a working position with the folding/unfolding mechanism held in a folded state; unfolding the folding/unfolding mechanism and setting up the working equipment under the structure after conveying the working equipment and the folding/unfolding mechanism to the working position; pressing the set up working equipment against a lower surface of the structure; moving the working equipment along the lower surface of the structure and positioning it; and doing a work on the structure by means of the moved and positioned working equipment. According to another aspect of the present invention, a working method for doing works under a shroud support plate arranged between a nuclear reactor pressure vessel and a shroud is provided. The method comprises: removing an access hole cover fitted to an access hole arranged at the shroud support plate; conveying a working equipment under the shroud support plate through the access hole after the cover removing step; and doing a work at a lower part in the nuclear reactor by means of the conveyed working equipment after the conveying step. Now, embodiments of the working apparatus and working method according to the present invention will be described referring to the accompanying drawings. Throughout the drawings, the same or similar components are denoted respectively by the same reference symbols and will not be described repeatedly. FIG. 1 is a schematic cross sectional view of the first embodiment of intra-nuclear-reactor working apparatus according to the present invention, showing how it is arranged in position. Referring to FIG. 1 that illustrates a lower part of a nuclear reactor that is the working site in the nuclear reactor, the site is found in a narrow area located below the shroud support plate 7 and surrounded by the inner wall of the nuclear reactor pressure vessel (RPV) 2, the shroud support cylinder 5 on which a nuclear fuel assemblies are placed, the shroud support legs 6 that are legs of the shroud support cylinder 5, and so on. The shroud support plate 7 is a horizontal annular plate arranged between the shroud support cylinder 5 and the RPV 2. A large number of weld lines are found in such a narrow area. They include an H8 horizontal weld line 9 that is the weld line connecting the shroud support cylinder 5 and the shroud support plate 7, and an H9 horizontal weld line 10 that is the weld line connecting the RPV 2 and the shroud support plate 7, along with an H10 weld line 11, an H11 weld line 12 and an AD-2 weld line 13. When conducting various works for these weld lines 9 to 13, such as inspection, polishing, water washing, preventive maintenance and repairing, the inside of the RPV 2 is filled with water and the intra-nuclear-reactor working apparatus 20 is arranged in the water. A cable (not shown) is connected to the intra-nuclear-reactor working apparatus 20 and the other end of the cable is connected to the control section and the operation section of the control apparatus arranged on the operating floor or on the fuel exchanger located above the RPV 2. Now, the intra-nuclear-reactor working apparatus 20 will be described below. FIG. 2 is a front view of the intra-nuclear-reactor working apparatus 20 of FIG. 1, showing the configuration thereof. FIG. 3 is a schematic plan view of the intra-nuclear-reactor working apparatus 20 of FIG. 1, showing the configuration thereof. FIG. 4 is a front view of the wheel folding/unfolding mechanism 32 of FIG. 1, showing the configuration thereof. As shown in the drawings, the intra-nuclear-reactor working apparatus 20 includes a cylindrical main body casing 22 that contains a ballast tank 21. Wheel folding/unfolding mechanisms 23, 32 for unfolding a working equipment 30 or a traveling wheel 24 are mounted in an upper part of the main body casing 22. At least three folded traveling wheels 24 to be unfolded are provided. The working equipment 30 is arranged between a pair of traveling wheels 24. Ball casters 25 are fitted respectively to upper parts of the three traveling wheels 24. An original point detection sensor 31 for defining an original point is fitted to an upper part of the intra-nuclear-reactor working apparatus 20. Two vertical thrusters 28 are fitted to a lower part of the main body casing 22 (although only one of them is shown in FIG. 4) so as to be driven by a drive motor 27. Further, two vertical thrusters 26 are fitted to a center part of the main body casing 22 (although only one of them is shown in FIG. 4) so as to driven by a drive motor (not shown). The main body casing 22 has a cylindrical profile and is dimensionally so designed as to be able to pass through a round hole (not shown) of the reactor core support plate 3. The total height of the intra-nuclear-reactor working apparatus 20 is dimensionally so defined that, after passing through the round hole of the reactor core support plate 3 and moving into a lower part of the reactor, the apparatus 20 can pass among the shroud support legs 6 and move into an area below the shroud support plate 7. A plurality of floats 29a, 29b are arranged at an upper part of the intra-nuclear-reactor working apparatus 20 so as to position the center of buoyancy above the center of gravity in water even after injecting air into the ballast tank 21 to completely fill the latter with air so that the intra-nuclear-reactor working apparatus 20 can hold its attitude without toppling down in water. As shown in FIG. 3, at least three wheel folding/unfolding mechanisms 23, 32 are arranged in the intra-nuclear-reactor working apparatus 20. Referring to the drawings, two floats 29a, a wheel 24 and a ball caster 25 are fitted to a single wheel folding/unfolding mechanism 23, whereas a float 29b is sandwiched between a pair of wheel folding/unfolding mechanisms 32, and a wheel 24 and a ball caster 25 are fitted to the front end of each of the wheel folding/unfolding mechanisms 32. The traveling wheels 24 of the wheel folding/unfolding mechanisms 23, 32 are driven by respective wheel drive motors 40 that are directly and coaxially linked to the rotary shafts thereof. A roller 46 for gauging the distance by which the roller traveled along the outer lateral surface of the shroud and a rotary sensor 45 directly linked to it are fitted to the lower end of each of the wheel drive motors 40. The traveling wheels 24, the rollers 46 and the rotary sensors 45 are linked to the main body casing 22 by way of parallel links 42 in such a way that each of the wheel folding/unfolding mechanisms can be stored in position with the wheel rotary shaft held upright by means of an air cylinder 41. Each of the parallel links 42 is supported at the opposite ends thereof by brackets 60 and pins 61 so as to be able to rotate freely. The intra-nuclear-reactor working apparatus 20 moves down below the shroud support plate 7 as the wheel folding/unfolding mechanisms 23, 32 are held upright and stored in position. Thereafter, the traveling wheels 24, the rollers 46 and the rotary sensors 45 are pressed against the shroud support cylinder 5 and the inner wall of the RPV 2 by supplying air to the air cylinders 41 to generate traveling drive force in a horizontal direction so that the intra-nuclear-reactor working apparatus 20 can move along the outer peripheral surface of the shroud. At the same time, it is possible to gauge the relative distance by which the intra-nuclear-reactor working apparatus 20 traveled along the outer peripheral surface of the shroud by means of the rollers 46 and the rotary sensors 45 pressed against the outer peripheral surface. While the driving air cylinders 41 are arranged at an upper part of the main body casing 22 in the illustrated embodiment, drive sources may alternatively be arranged below the ballast tanks 21 for the wheel folding/unfolding mechanisms 23, 32 to produce links that can be unfolded by the drive sources. With such an arrangement, the attitude of the intra-nuclear-reactor working apparatus 20 can be made more stable in water because the center of gravity is lowered by the arrangement. Now, how the intra-nuclear-reactor working apparatus 20 is handled will be described below. FIG. 5 is a front view of the intra-nuclear-reactor working apparatus 20 of the first embodiment according to the present invention, showing how it is operated, and FIG. 6 is a plan view of the intra-nuclear-reactor working apparatus of this embodiment, also showing how it is operated. The intra-nuclear-reactor working apparatus 20 is adapted to carry out various operations, for instance, on the H8 horizontal weld line 9 that is the weld line located under the shroud support plate 7 as shown in FIG. 1. The intra-nuclear-reactor working apparatus 20 is suspended from above the RPV 2 by means of a cable (not shown) and lowered into the RPV 2 that is filled with water. Then, it is moved into a narrow area located in a lower part of the reactor, passing by an upper grid plate and the reactor core support plate 3. At this time, the insides of the ballast tanks 21 are evacuated and water is injected into them to reduce the buoyancy and generate a falling force. At the same time, downwardly propelling force of the vertical thrusters 28 are combined with the falling force to drive the intra-nuclear-reactor working apparatus 20 downwardly in water. Then, the intra-nuclear-reactor working apparatus 20 is made to pass among the shroud support legs 6 and go below the shroud support plate 7. When driving the intra-nuclear-reactor working apparatus 20 to move, air is injected into the ballast tank 21 or water is discharged from the inside of the ballast tank 21 to make the weight of the entire apparatus substantially equal to 0 kgf in water and drive the apparatus horizontally by means of the horizontal thrusters 26. Then, the working equipment 30 made to face the shroud support cylinder 5 by rotating it around the vertical axis. Thereafter, the traveling wheels 24 are unfolded until immediately before they touch the outer peripheral surface of the shroud support cylinder 5. Then, air is injected into the ballast tank 21 to expel the water in the inside and lift up the intra-nuclear-reactor working apparatus 20 until the three ball casters 25 touch the lower surface of the shroud support plate 7. As the vertical position of the intra-nuclear-reactor working apparatus 20 is determined in the above-described manner, the unfolding power is raised to press the traveling wheels 24 firmly against the shroud support cylinder 5 and the inner wall of the RPV 2. For traveling, the traveling wheels 24 are driven to turn, while the ball casters 25 are constantly held in contact with the lower surface of the shroud support plate 7 by the buoyancy generated by the ballast tank 21. Then, as a result, it is possible to move the intra-nuclear-reactor working apparatus 20 horizontally along the H8 weld line 9. The reference position in a peripheral direction for the H8 horizontal weld line 9, or the original point for traveling, is defined by detecting the inner edge of the round hole of the shroud support plate 7 where the jet pump adaptor 8 is rigidly anchored by means of an original detecting sensor 31, which may typically be an ultrasonic distance sensor. Then, the rollers 46 are made to contact the wall surface to directly gauge the traveled distance by the rotary sensors 45 and computationally determine the traveled relative distance from the original point by the rotary sensors 45. Then, the intended work is carried out by means of an appropriate one of the various pieces of working equipment 30, while remotely regulating the relative position and the attitude of the apparatus relative to the target of work by means of the scanning mechanism. If the work is a visual inspection, a CCD camera is mounted as working equipment 30 and a universal head is mounted as scanning mechanism. Then, the weld line and its vicinity will be continuously shot, while moving the apparatus horizontally and regulating the universal head and the camera angle so as to shoot the desired region. Alternatively, an ultrasonic flaw detection sensor or an eddy current flaw detection sensor may be mounted with a scanning mechanism having a desired degree of freedom to carry out a similar work. Any of various works can also be performed for the H9 horizontal weld line 10 by moving so as to make the working equipment 30 face the inner wall of the RPV 2 and unfolding the related components, following a similar sequence of operation. With this embodiment, it is possible to perform a preventive maintenance operation or a welding operation such as an inspection, a cleaning operation, a polishing operation, water washing, water jet peening and/or a laser peening operation to a weld line that is found in a hard-to-be-accessed area below the shroud support plate 7 when conducting any of various operations on the intra-reactor structures in the nuclear reactor pressure vessel that is immersed in water in a nuclear reactor. Additionally, the working apparatus can cover a wide area with a limited number of times of immersions of installations to carry out works efficiently. Still additionally, since the traveling wheels 24 are unfolded and pressed against a wall, it is possible to support a large reaction force and hence carry out a work stably. Furthermore, since the intra-nuclear-reactor working apparatus can continuously travel on the outer wall surface of the shroud support cylinder 5 by means of the traveling wheels 24, it is possible to accurately and continuously position the apparatus and restore the apparatus to an original position. Thus, it is possible to improve the quality of the work it carries out. Sine the intra-nuclear-reactor working apparatus can move along the lower surface of the shroud support plate 7 by utilizing buoyancy, the vertical position of the apparatus can be reliably secured to further improve the quality of the work it carries out. The working equipment 30 is selected from a brush for polishing operations, a grinding jig, a washing water nozzle, a water jet peening head for preventive maintenance, a laser peening head and a welding head for repairing works and mounted in the intra-nuclear-reactor working apparatus. Thus, by using any of these pieces of working equipment 30, it is possible to perform polishing operations, cleaning operations, operation for improving stresses as preventive maintenance and repairing operations. Therefore, with this embodiment, it is possible to perform, in addition to inspection, polishing operations, cleaning operations, operation for improving stresses as preventive maintenance and repairing operations on the weld lines located in a narrow area under the shroud support plate which is difficult to access. In this embodiment, the conveyance mechanism of the intra-nuclear-reactor working apparatus is realized by the two horizontal thrusters 26 and by regulating the buoyancy of the ballast tank 21. More specifically, the embodiment is driven to move up and down respectively by the rising power and the falling power generated by the ballast tank 21. It is driven to move horizontally and turn around a vertical axis by the propelling force of the horizontal thrusters. This embodiment provides improved handling capabilities because the degree of freedom of driving and the number of cables are reduced. Additionally, it is possible to make the intra-nuclear-reactor working apparatus 20 submerge and surface or become pressed against the lower surface of the shroud support plate with a simplified structure. In this embodiment, preferably the traveling wheels 24 are rubber wheels having a shape of a truncated cone that are fitted in position with the larger diameter side facing downward. With this arrangement, it is possible to apply an upwardly displacing force to the apparatus as the traveling wheels 24 are pressed against a wall surface and driven to rotate. Then, along with the buoyancy of the ballast tank, it is possible to firmly press the apparatus against the lower surface of the shroud support plate so that the apparatus can securely move horizontally along the shroud support plate. FIG. 7 shows the second embodiment of intra-nuclear-reactor working apparatus according to the present invention. The components of this embodiment that are same as or similar to those of the first embodiment are denoted respectively by the same reference symbols and will not be described in detail any further. This embodiment differs from the first embodiment illustrated in FIG. 2 in that the drive mechanism 32 for supporting the working equipment 30 and the float 29b includes two links that are arranged adjacently in a horizontal direction. Otherwise, this embodiment is identical with the first embodiment. Now, the third embodiment of the present invention will be described below by referring to FIGS. 8 and 9. The components of this embodiment that are same as or similar to those of the first embodiment are denoted respectively by the same reference symbols and will not be described in detail any further. As shown in FIGS. 8 and 9, an upper grid plate 43 having an opening and a reactor core support plate 3 having an opening are arranged in the pressure vessel 2. The intra-nuclear-reactor working apparatus 20 is led to an area located under the shroud support plate 7 by way of either of two routes 44, 145, one for accessing the area under the shroud support plate 7 from the inner surface side of the shroud 100, passing through the opening of the upper grid plate 43 and the opening of the reactor core support plate 3, and one for accessing the area under the shroud support plate 7 from the outer surface side of the shroud 100, passing through the access hole 46a. This embodiment can carry out any of various works on the intra-nuclear-reactor structures in the pressure vessel 2 that is immersed in water in a nuclear reactor regardless of the intra-nuclear-reactor environment. More specifically, it can be used to carry out any of various works on the H8 horizontal weld line 9 that is the weld line of the shroud support cylinder 5 and the shroud support plate 7, the H9 horizontal weld line 10 that is the weld line of the pressure vessel 2 and the shroud support plate 7, the H10 weld line 11 that is the weld line of the shroud support legs 6 and the shroud support cylinder 5, the H11 weld line 12 that is the weld line of the shroud support legs 6 and the pressure vessel 2, the AD-2 weld line 13 that is the weld line of the jet pump 8 and the shroud support plate 7. For instance, if all the control rod guide tubes 141 and the fuel are installed and it is not possible to take the access route 44 leading to an area under the shroud support plate 7, it is possible to take off the access hole cover 146 and take the access route 145. As shown in FIGS. 10 and 11, the access hole 46a arranged in the pressure vessel 2 is covered by the access hole cover 146. The access hole cover 146 is rigidly secured to the peripheral edge 46b of the access hole 46b by means of a total of six bolts (binding sections) 50 and a retainer 52 is arranged between the access hole cover 146 and each of the nuts 51. Each of the bolts 50 is engaged with a nut 51 and the stoppers 53 that operate as anti-revolution means are formed by using spring mechanisms. Thus, the bolts 50 can be fitted and removed with ease. Since the stopper 53 of each of the bolts 50 is formed by using a spring mechanism 53, the access hole cover 146 can be fitted and removed with ease by means of a handling jig that is exclusively designed as anti-revolution key. With this arrangement, it is possible to easily carry out operations including inspections, polishing, washing with water, water jet peening, laser peening for preventive maintenance, and repairing operations such as welding in an area located below the shroud support plate 7 by removing the access hole cover 146 if the reactor is loaded with the fuel (not shown) and the control rod guide tubes 141 in the inside. Now, the fourth embodiment of intra-nuclear-reactor working apparatus according to the present invention will be described below. In this embodiment, the mechanism constituting members and the strength holding members of the intra-nuclear-reactor working apparatus and the working equipment are formed by using a polymeric resin material. Specific examples of materials that can be used for this embodiment include polyamide type resins, polyimide type resins, polyether-ether-ketone resins and polyether-sulfone-resins that are excellent in terms of resistance against radioactive rays, water-absorbing property, mechanical strength and thermal resistance. All or part of these materials may be used for the above mechanism composing members and the strength holding members. Thus, with this embodiment, it is possible to replace polymeric resin materials in place of metal materials in order to reduce the weight of the various pieces of equipment, such as an intra-nuclear-reactor working apparatus or working equipment in water. As a result, the ballast tank can be dimensionally reduced to consequently reduce the overall dimensions of the apparatus. As the apparatus is made lightweight and downsized, it can be handled easily and it can pass through narrow areas so that the reliability of operation of the apparatus is also improved. The present invention is not limited to the above-described embodiments, which may be modified in various different ways without departing from the scope of the present invention. For example, inspection results may be displayed on a display apparatus. For example, while the above-described embodiments of intra-nuclear-reactor working apparatus and working method are adapted to be used in nuclear reactors, the present invention can broadly be applied various working apparatus and various working methods. Additionally, while the above-described embodiments of working apparatus and working method are adapted to operations in water, they can be modified in various different ways as pointed out below. For example, while the operation mechanisms including the adhering/traveling modules 22 and related mechanisms may be housed in a water-tight case or the like and adapted to perform adhering/traveling operations in water, the working equipment of a working apparatus according to the present invention may be separated from them and put in air so as to operate in air. As another example, the adhering/traveling modules 22 and the thrusters 41 may be dimensionally raised to use a large drive source and a large drive mechanism for the thrusters 41 so that the thrusters 41 may acquire a sufficiently large air flow rate to produce a large adhering force in air as they are driven to rotate at high speed. With such an arrangement, a working apparatus and a working method according to the present invention may be applied to works in air. |
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039792579 | description | DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows a boiling-water reactor 1, a removable cover 2 closing the top of a pressure vessel 3 by means of a releasable flange connection 4. In the lower portion or lower third of the pressure vessel the reactor core 5 is positioned, this core comprising any of the prior art arrangements of individual fuel rod assemblies. Feed water is fed in through a feed-water inlet 6 and pumped outwardly through the reactor core 5 by a pump 7 having a motor 8 outside of the vessel. Above the reactor core 5 there is a steam collection dome 10 by which steam generated from the feed-water flow upwardly through the reactor core is collected, the steam discharging into water separators 12 which are structurally connected with or combined with a control rod guide arrangement 11 for a control element or assembly 13. An extension of the control rod guide 11 goes through the steam space 14 in the upper part of the vessel 3 where steam dryers 15 are additionally accommodated. The steam flows through the latter before leaving the pressure vessel via its steam outlet 16. The drive 17 for the control rod assembly 13 is arranged outside of the vessel and above its removable cover 2. This drive may be hydraulic or electric and in particular it may be an electro-magnetic mechanism. FIG. 1 shows that in spite of the pump motor 8 only little space is required underneath the reactor core 5 so that the reactor, as a whole, may have a low center of gravity when positioned in its usual concrete containment. This provides high stability and, therefore, greater safety against earthquakes occurring at the reactor installation. In FIGS. 2 and 3 two possibilities for guiding the control rods in the separator 12 are shown. In FIG. 2 a control rod assembly 13 with a cross-shaped profile is shown seated in the cylindrical separator 12. The cross is guided at the free ends of all of its arms by two parallel flanges 18, in each instance, so that it is accurately fixed insofar as its position in the reactor core is connected. In spite of this accurate guidance, which ensures the correct engagement of the control rod elements in the gaps normally formed in the fuel assemblies of the core 5, the external space required for the separator 12 is not increased at all, while the clear cross section of its interior is not affected appreciably by the control rod assembly. In FIG. 3 a cluster rod assembly is shown comprising four symmetrically distributed, so-called finger rods 21 associated with a central drive rod 20. The finger rods consist of neutron-absorbing material and are fastened at the drive rod end 20, at the upper finger rods ends via arms 22. The finger rods 21 are guided in tracks 23 which have cutouts fitted to the circular cross section of the finger rods 21 and are attached to the inside of the separator 12. Again only little space is, therefore, required inside of the separator 12 and no additional space on the outside is required at all. A side view on a larger scale is shown for the lastmentioned embodiment, in FIG. 4. The finger rods 21 run above the steam dome 10 in a standpipe 25 firmly connected with the steam dome 10. The standpipe 25 encloses the previously mentioned tracks 23 which extend down and end just above the reactor core 5 and are held together by a ring 26. The standpipe 25 also serves as an outlet for the steam, which is conducted into water separators 12 enclosing the standpipe 25. By means of baffles 27 provision is made here for a flow-wise favorable deflection, the separated water being returned downwardly into the core 5, while the steam leaves in an upward direction into the steam space 14. Above the separator 12 a steam dryer 15 is further provided which is also structurally combined or connected with a guide tube 30 for the control rod drive. The individual finger rods 21 can be associated with a single fuel assembly or with several adjoining fuel assemblies. Their length, which is provided with absorbing material, is advantageously shorter than the length of the tracks 23, so that the effect of the neutron-absorbing material, which can also be capable of burnoff, can be utilized locally targeted. In FIG. 5 the guidance of the control rod 13 in the interior of the core 5 is indicated, this figure showing on the left side the guidance for a finger control rod, and on the right, for a so-called cross rod as shown by FIG. 2. It can be seen that in the fuel assembly 32 one guide tube 33 is provided for each of the fingers 21. The guide tube 33 consists preferably of Zry 4 or a zirconium-niobium alloy; it extends almost to the lower core plate 35 and is part of the fuel assembly support structure. For this reason, it may be possible in some cases to dispense with the otherwise customary fuel element case. A shock absorber 34 is shown there. The control guide tube 33 progressively reduces in diameter as at 37 and 38 and is filled with the water. If the control rod is dropped, it successively displaces decreasing amounts of water providing a progressively increasing resistance to its fall, providing a shock-absorbing action. |
abstract | A control rod grasped by a hook of a grasping equipment is moved down and is positioned at an upper end of a hollow piston of a control rod drive mechanism (CRD) in a state that the control rod is fully withdrawn from a core. Furthermore, the hook is inserted into an opening of a handle of the control rod. The hook is lifted up so as to make contact with the handle. The control rod grasped by the grasping equipment is rotated by a grasping equipment rotation apparatus. A state that gaps formed between joint convexities in a coupling socket of the control rod are positioned right above coupling spud convexities of the hollow piston occurs. At this time, the control rod falls by its own weight and the coupling spud convexities pass through the gaps. A grasping equipment movement apparatus suppresses the falling speed of the control rod. The control rod is rotated at 90° and the control rod and CRD are connected. The time required for connecting the control rod and the hollow piston of the control rod drive mechanism can be shortened even further. |
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063046326 | abstract | The movement of an anti-scatter grid in a radiography apparatus is a continuous curve having point symmetry with respect to the point whose time coordinate is equal to half the exposure time, and for which the space derivative of the time variable has two linear portions which are symmetrical with respect to a symmetry axis passing through the middle of the range of movement of the grid. The grid is moved with a high rate of movement close to the starting position and the end position. |
summary | ||
summary | ||
046648690 | summary | BACKGROUND OF THE INVENTION The invention relates to a practical method for commercially producing radiopharmaceutical activities and, more particularly, relates to a method for the preparation of about equal amount of Radon-211 (.sup.211 Rn) and Xenon-125 (.sup.125 Xe) including a one-step chemical procedure following an irradiation procedure in which a selected target of Thorium (.sup.232 Th) or Uranium (.sup.238 U) is irradiated. The disclosed method is also effective for the preparation in a one-step chemical procedure of substantially equal amounts of high purity .sup.123 I and .sup.211 At. In many research applications it is desirable to have available the relatively long-lived radio-iodine isotope labels that have been found to be very useful in studying disease processes. In other applications, such as for therapeutic radiation dose treatment of certain human diseases, it has been found that the radionuclide .sup.211 At is very useful. It is also known that .sup.123 I is ideal for imaging in nuclear medicine, while .sup.211 At has desirable properties as a label of therapeutic radiopharmaceuticals that are used in the treatment of human diseases such as cancer and rheumatoid arthritis. Accordingly, it is recognized that a method for affording simultaneous production of about equal amounts of .sup.125 Xe and .sup.211 Rn would be of considerable value in making systematic investigations of the energetic and ionic reactions of .sup.125 I and .sup.211 At (the daughters of .sup.125 Xe and .sup.211 Rn, respectively) during excitation labeling of organic compounds. Moreover, conclusions concerning the chemistry of astatine are often drawn by extrapolation from iodine chemistry. Moreover, it is desirable to label organic compounds intended for biomedical studies with both iodine and astatine isotopes in order to ascertain biochemical behavior and in vivo stability. Thus, a method of preparing both the radionuclides (.sup.211 Rn and .sup.125 Xe) in a relatively carrier-free state is of value, because such extrapolations will thus be made more economically practical in view of the fact that with such a method the radiochemical yields can be optimized. Before the development of the invention disclosed herein, it is not believed that any other processes or methods existed for the commercially practical, simultaneous preparation of substantially equal amounts of .sup.211 Rn and .sup.125 Xe. By practicing the method of the invention, such useful quantities of high radionuclidic purity, carrier-free .sup.211 At and .sup.125 I can be readily prepared. Accordingly, by the method of the invention, a single source containing both of those parent radionuclides is made available for dual-tracer preparation of radiopharmaceuticals, such as monoclonal antibodies. Also, the method of the invention enables the preparation of high purity .sup.123 I and .sup.211 At, in the same chemical form and media, so that truly double-labeled compounds, which must be obtained in high specific activity for diagnostic and therapeutic applications, can be achieved. The chemistry of .sup.211 At is particularly difficult, because there are no stable isotopes of that element, so chemistry with .sup.211 At is generally based upon extrapolation from iodine chemistry. Thus, it is believed that the types of double-labeled radiopharmaceuticals, that can be economically prepared by practicing the method of the invention, will have future applications where the labeled compound can be administered to a patient, with the .sup.123 I label being used to locate a given desired site, such as the site of a tumor, for example, while the .sup.211 At is used for therapeutic treatment of the site. As indicated above, .sup.211 At does not have nuclear decay properties that would permit its use for imaging and, on the other hand, there are no alpha-emitting radionuclides of iodine, which would permit their therapeutic use. Prior to the present invention, it was known that high purity .sup.211 Rn could be prepared by bombarding .sup.209 Bi with .sup.7 Li particles, for example, in a type of method such as that described in U.S. Pat. No. 4,364,898 which issued Dec. 29, 1982. However, that patent and related prior art methods do not disclose or suggest a method for simultaneously producing substantially equal amounts of radionuclides that are suitable for double-labeling compounds in the manner explained above. In the applicants' co-pending U.S. patent application, Ser. No. 598,624, which was filed Apr. 10, 1984, there is disclosed a process for reliably producing a .sup.211 At radiopharmaceutical by a process that includes forming a suitable bismuth target and then irradiating it with alpha particles, preparatory to chemically treating the target to elute .sup.211 At, which is then collected in a controlled volume of eluent for use in selected radiopharmaceutical procedures. The disclosure of that co-pending U.S. patent application is referred to and incorporated herein by reference for its teaching of suitable techniques for forming radiation target bodies and target backing materials, as well as for the techniques described therein for irradiating such target materials. OBJECTS OF THE INVENTION A primary object of the invention is to provide a method for reliably and consistently preparing nearly equal amounts of .sup.211 Rn and .sup.125 Xe, simultaneously, using a one-step irradiation of a single target to form useful quantities of selected isotopes, followed by a chemical extraction and purification procedure, all hereinafter referred to simply as a one-step chemical procedure. Another object of the invention is to provide a method for simultaneously obtaining comparable quantities of high purity .sup.123 I and .sup.211 At. A further object of the invention is to provide a method for preparing at least two radionuclides in the same chemical form and media so that they can be used together to facilitate subsequent chemistry. Yet another object of the invention is to provide a method for the simultaneous preparation of .sup.211 Rn and .sup.125 Xe, which method utilizes a novel one-step irradiation and subsequent distillation and collection procedure, our so-called one-step chemical procedure. Still another object of the invention is to provide a method of for readily preparing .sup.211 Rn, .sup.211 At, .sup.125 Xe, .sup.125 I, .sup.123 Xe, and .sup.123 I using a one-step chemical procedure that yields a first mixture of about equal amounts of .sup.211 Rn and .sup.125 Xe, and a separate second mixture of about equal amounts of .sup.123 I and .sup.211 At. Additional object and advantages of the invention will become apparent to those skilled in the art from the description of it presenting herein, considered in conjunction with the accompanying drawings. SUMMARY OF THE INVENTION In one preferred arrangement of the invention almost equal quantities of .sup.211 Rn and .sup.125 Xe are prepared using a one-step chemical procedure in which a suitably irradiated fertile target material, such as thorium-232 or uranium-238, is treated to extract those radionuclides from it. In the same one-step chemical procedure about equal quantities of .sup.211 At and .sup.123 I are prepared and stored for subsequent use. In a modified arrangement of the method of the invention, it is practiced to separate and store about equal amounts of only .sup.211 Rn and .sup.125 Xe, while preventing the extraction or storage of the radionuclides .sup.211 At and .sup.123 I. |
claims | 1. A background reduction system comprising:a charged particle source configured to generate a charged-particle beam; anda louvered structure including one or more apertures configured to selectively transmit charged particles according to their angle of incidence;a charged-particle detector configured to receive charged particles selectively transmitted by the louvered structure. 2. The background reduction system of claim 1, wherein the angle of incidence is from about 10 degrees to about 50 degrees. 3. The background reduction system of claim 1, wherein the charged-particle beam is directed onto a target substrate. 4. The background reduction system of claim 1, wherein the louvered structure is configured for selectively transmitting secondary charged particles emitted from the target substrate. 5. The background reduction system of claim 1, wherein the louvered structure comprises a particle-absorbing composition. 6. The background reduction system of claim 1, wherein the particle-absorbing composition is a particle-absorbing coating of a base louvered substrate. 7. The background reduction system of claim 1, wherein the louvered structure includes a first portion including one or more apertures having a first angle of acceptance and a second portion including one or more apertures having a second angle of acceptance different than the first angle of acceptance. 8. The background reduction system of claim 1, wherein the charged-particle detector is a position-sensitive charged-particle detector. 9. The background reduction system of claim 1, wherein one or more apertures of the louvered structure are substantially linear in shape. 10. The background reduction system of claim 1, wherein one or more apertures of the louvered structure are at least partially arcuate in shape. 11. A method for background reduction comprising:generating a charged-particle beam;disposing a louvered structure in a path of one or more charged particles for selectively transmitting one or more charged particles according to an angle of incidence of the one or more charged particles; anddetecting one or more selectively transmitted charged particles. 12. The method of claim 11, wherein the angle of incidence is from about 10 degrees to about 50 degrees. 13. The method of claim 11, further comprising:directing the charged-particle beam onto a target substrate. 14. The background reduction system method of claim 13, wherein the disposing a louvered structure in a path of one or more charged particles for selectively transmitting one or more charged particles generated by the charged-particle beam according to an angle of incidence of the one or more charged particles comprises:disposing a louvered structure in a path of one or more secondary charged particles emitted from the target substrate for selectively transmitting the one or more secondary charged particles emitted from the target substrate according to an angle of incidence of the one or more secondary charged particles. 15. A system for background reduction system comprising:means for generating a charged-particle beam;means for disposing a louvered structure in a path of one or more charged particles for selectively transmitting one or more charged particles according to an angle of incidence of the one or more charged particles; andmeans for detecting one or more selectively transmitted charged particles. 16. The method system of claim 15, wherein the angle of incidence is from about 10 degrees to about 50 degrees. |
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049884743 | description | DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a nuclear reactor fuel assembly 1 in an overview. It consists of many fuel rods 2, which are held in their position by several interim spacer supports 3 which are axially separated. Upper and a lower fuel assembly tie plates 4, 5 are held together by guide tubes that are not shown. The guide tubes or an instrumentation tube, also not shown, carry the spacer supports and attach them at their axial interval. As can be seen from FIG. 2, which shows a partial region of a spacer support on a larger scale, each fuel rod 2 passes through a cell 6, so that it is enclosed by four crosspieces 7 that form the cell, whose jut-out pieces 8 formed in part elastically contact fuel rod 2. If crosspieces lying at the periphery of the spacer support are damaged, then they are removed and their function is taken over by a holding component 9 described in more detail below. The repair process and the respective holding component 9 can be recognized from FIG. 3. Cell 6 exists only as a cell carcass of a fuel rod 2 (corner rod) positioned on a corner of spacer support 3, after separation of the damaged piece 7 indicated by the dot-dash line. A holding component 9 has, as can also be seen in FIGS. 4-8, on each of its free ends an elastically formed projection 10, which engages in a slot 11 of a cross piece 7. The holding component 9 contacting a fuel rod 2 over a part of its circumference thus fixes the fuel rod and prevents an undesired swinging of this fuel rod. The elastic projections assure, on the one hand, a precise positioning of the rod, and, on the other hand, permit a vertical displacement of the fuel rod for equilibrating heat expansions and radiation-conditioned longitudinal changes. Several examples of embodiments of holding component 9 can be seen in FIGS. 4-8. All of the embodiments consist of a metal strip, which displays on its free ends formations of projection 10 engaged in a slot 11 of the crosspiece, which formations are adapted to the particular dimensions of the respective fuel rod. Whereas FIG. 4 shows a holding component consisting of a metal strip, a holding component can be seen from FIGS. 5 and 8, which is provided with a recess 12 for adapting to the elastic force. A jut-out piece 13 according to FIG. 7 which is formed elastically if necessary, reduces the contact surfaces between fuel rod 2 and holding component 9 and also simplifies the passage of the coolant between the fuel rod and the holding component. A holding component 9 with projections 10 according to FIG. 6 with slightly angled sides formed elastically simplifies the introduction of the holding component into grooves 11 of the cell carcass; in this case the latter are arranged at the intersecting points of two crosspieces 7. The metal strip for producing a holding component consists of a material (e.g. Inconel 718 or 750 ), which retains its spring properties even during irradiation. An example of embodiments, which shows a holding component for a "non-corner rod" is described by FIGS. 11 and 12. After removing the peripheral crosspiece 7, a cell carcass with three crosspieces remains. The holding component 9 according to FIG. 11 consists of a sheet metal adapted to the contour of the fuel rod, of which upper and lower edges 14 extend hook-shaped projections 10a. They are also formed elastically and are set into crosspieces 7. The removal of the damaged crosspiece 7 of a cell 6 may be conducted with an installed fuel rod. However, it may also be necessary to dismantle the fuel rod and to replace it by a new fuel rod or a dummy fuel rod 15. The previously described holding components may be inserted for the dummy fuel rod. In order to secure the holding component against axial displacement, a dummy fuel rod 15 may display a snap ring groove 16 (FIG. 9) and/or also a longitudinal groove 17 (FIG. 10). The snap ring groove 16 is thus adapted to the height of a holding component such that there is sufficient play for assuring the rod motion for equilibration of heat expansions. This form of embodiment has the advantage that no parts exist that project over the dummy fuel rod and that would offer an attack surface, e.g., for catching onto the adjacent fuel assembly. The axially running longitudinal groove 17 is then necessary if a mounting tool has parts projecting inside above the holding component. Another form of embodiment directed in particular for use with a dummy fuel rod 15 is shown in FIG. 13. Accordingly, by running crosswise to the axis the dummy fuel rod 15 passes through borehole 18, which is provided with a depression 19. The holding component 9a is formed like a type of split pin. It has a head 20, from which extend two arms 21 formed elastically, which arms have projections 10 of the type shown in FIGS. 4-8 on their free ends, each of which extend from holding component 9. After passing through borehole 18, whereby projections 10 lie against the borehole wall, elastically, arms 21 spread apart again and engage with their projections 10 into slot 11 of crosspieces 7 of spacer support 3. The head 20 of holding component 9a thus comes to lie on the shoulder of depression 19, so that the fixed position of the dummy fuel rod 15 is produced. |
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description | The present invention relates generally to radiotherapy and irradiation systems, and particularly to an adjustable aperture collimator useful in such radiotherapy and irradiation systems. Multi-leaf collimators (MLCs) are used in radiotherapy for aperture forming intended to shape a radiation beam. Examples of multiple layer MLCs include those described in U.S. Pat. Nos. 6,266,393 and 6,526,123 and to Ein-Gal, the disclosures of which are incorporated herein by reference. MLCs provide a stationary aperture for radiotherapy. Dynamic aperture formation is also known in the art. For example, U.S. Pat. No. 4,868,843 to Nunan describes a system that dynamically controls an x-ray field of a fan beam. A multileaf collimator is positioned in the fan beam including a first set of leaves which can be individually moved into or out of the fan x-ray beam to block or pass individual radiation pixels. Continuous monitoring of alignment of the patient's anatomy with both inner and outer edges of the fan beam is obtained with a linear detector array retractably mounted on the opposite side of the patient from the x-ray source. Tapered extensions, added to a second opposite set of leaves of the MLC are variably positionable to attenuate the dose rate in individual radiation pixels of the fan x-ray beam. The patient scan is obtained by moving the patient perpendicularly to and through the fan x-ray field while the dose delivered in each radiation pixel is dynamically controlled. Normal tissue is protected by the positions of the first set of leaves of the MLC, which attenuate transmission to less than 5% of open field dose. Depth variations from the patient surface to the plane at treatment depth are compensated at each radiation pixel of the field by the positions of the tapered extensions of the second, opposite, set of leaves of the MLC, providing variable transmission from 50% to 100% of open field dose, for example. Reduced dose to critical organs such as the spinal cord can thereby be delivered in each treatment fraction However, dynamic aperture formation for target tracking requires leaf speed significantly higher than presently available. Increasing MLC leaf speed is presently complicated and expensive. The present invention seeks to provide a novel device and method for aperture formation for MLCs, which can provide fast aperture motion, as is described hereinbelow. There is thus provided in accordance with an embodiment of the present invention a collimator including an inner border whose inner perimeter defines an aperture, an outer border positioned outwards of the inner border, an enclosure being defined and bounded between the inner and outer borders, the enclosure being sufficiently filled with a radiopaque pliable material so as to block a predefined amount of radiation from passing through the enclosure, while allowing radiation to pass through the aperture, and at least one actuator attached to at least one point of the inner border operable to deform the inner border so as to modify a shape of the aperture. The radiopaque pliable material may include a radiopaque liquid, a radiopaque powder, a dispersion (e.g., suspension or emulsion) of powdered radiopaque material in a carrier or a radiopaque gas. The inner border may be constructed of a flexible material, such as rubber. A sensor may be provided that senses a parameter related to irradiation. The sensor is in operative communication with the at least one actuator, and the at least one actuator changes the shape of the aperture in accordance with information sensed by the sensor. The collimator may further include apparatus for determining position and shape of the aperture (e.g., a camera). There is also provided in accordance with an embodiment of the present invention an irradiation system including a source of radiation that emits a radiation beam, and a collimator that collimates the radiation beam, the collimator including an inner border whose inner perimeter defines an aperture, an outer border positioned outwards of the inner border, an enclosure being defined and bounded between the inner and outer borders, the enclosure being sufficiently filled with a radiopaque pliable material so as to block a predefined amount of radiation from passing through the enclosure, while allowing radiation to pass through the aperture, and at least one actuator attached to at least one point of the inner border operable to deform the inner border so as to modify a shape of the aperture. Reference is now made to FIG. 1, which illustrates an irradiation system 10 with an adjustable aperture collimator 12, constructed and operative in accordance with an embodiment of the present invention. In the non-limiting illustrated embodiment, irradiation system 10 (e.g., a LINAC) includes a gantry 14 which can be rotated about a horizontal axis 16 in the course of a therapeutic treatment. Collimator 12 is fastened to an extension of gantry 14 in which is disposed a source 18 of radiation, such as a linear accelerator, for generating a radiation beam 20. Any radiation may be used, such as but not limited to, electron radiation or photon radiation (gamma radiation). As is known in the art, during treatment, beam 20 is trained on a target which lies in the isocenter of the gantry rotation. Imaging apparatus (not shown), such as a fluoroscope or ultrasound apparatus, for example, may be provided for imaging the target irradiated by radiation beam 20. The imaging apparatus may be used in conjunction with a closed loop, feedback control system (not shown) for controlling a position of gantry 14 and for controlling the functioning of collimator 12. Reference is now made to FIG. 2, which illustrates the adjustable aperture collimator 12 of FIG. 1, in accordance with a non-limiting embodiment of the present invention. Collimator 12 includes an inner border 22 (of any arbitrary shape) whose inner perimeter defines an aperture 24 (of any arbitrary shape). The inner border 22 may be constructed of a flexible material, such as rubber. An outer border 26 (of any arbitrary shape) is positioned outwards of the inner border 22. The outer border 26 may be constructed of a flexible material, such as rubber, or of a rigid material, such as metal. An enclosure 28 is defined and bounded between the inner and outer borders 22 and 26. Enclosure 28 is sufficiently filled with a radiopaque pliable material 30 so as to block a predefined amount of radiation from passing through enclosure 26, while allowing radiation to pass through aperture 24. One or more actuators 32 are operatively attached to one or more points of inner border 22. Actuators 32 are operable to deform the inner border 22 so as to modify a shape of aperture 24. For example, actuator 32 may be a solenoid or linear actuator with a push-pull rod attached to the perimeter of inner border 22. The radiopaque pliable material 30 may include a radiopaque liquid, gas, powder, paste or thixotropic material. For example, the radiopaque pliable material 30 may include a radiopaque liquid, such as but not limited to, perfluorooctylbromide, a mixture of perfluorooctylbromide with other fluorocarbon liquids, or other radiopaque liquids such as barium sulfate, or any combination thereof. The radiopaque pliable material 30 may include a radiopaque powder, paste or thixotropic material, such as but not limited to, lead, tin, tungsten, antimony, bismuth, bismuth oxide, or any mixture thereof, or a dispersion (e.g., suspension or emulsion) of powdered radiopaque material in a carrier. The radiopaque pliable material 30 may include a radiopaque gas, such as but not limited to, xenon or krypton. The radiopaque pliable material 30 may include any combination of all or some of the above. A sensor 34 may be provided that senses a parameter related to irradiation, such as but not limited to, radiation dosage, position of patient, position of tumor, temperature of tumor, etc. Sensor 34 may be a position sensor, accelerometer, capacitance sensor, radiation dose sensor, temperature sensor, etc. Sensor(s) 34 may be in operative communication with the actuator(s) 32 which change the shape of aperture 24 in accordance with information sensed by sensor(s) 34. The collimator 12 may further include apparatus 36 for determining position and shape of the aperture (e.g., a camera). Sensor(s) 34 and apparatus 36 may operate in a closed loop control with actuator(s) 32 for changing and monitoring the shape of aperture 24. Collimator 12 may be mounted on a movable interface 38 (FIG. 1) (e.g., an XY table or a turntable and the like) attached to gantry 14 at the output of radiation source 18. The movable interface 38 is operable to receive target positional data (from sensors 34, actuators 32 or apparatus 36 or other controllers or sensors or combination thereof) and accordingly move collimator 12 (and the associated aperture 24) relative to the radiation source 18 (typically, in a plane generally perpendicular to radiation beam 20) so that the radiation beam 20 that passes through aperture 24 is generally oriented toward the target (statically and/or dynamically). The scope of the present invention includes both combinations and subcombinations of the features described hereinabove as well as modifications and variations thereof which would occur to a person of skill in the art upon reading the foregoing description and which are not in the prior art. |
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056299656 | description | PREFERRED EMBODIMENTS OF THE INVENTION An embodiment of the present invention will be explained hereinbelow with reference to FIG. 1. FIG. 1 shows a control element included in a diving bell type control rod equipped with a sodium inflow port according to one embodiment of the present invention. This control element comprises a cladding tube 1 immersed in a sodium coolant, a pellet chamber 3 for loading pellets 2 of B.sub.4 C formed inside the cladding tube 1, an intermediate plug 4 disposed above the pellet chamber 3, an upper chamber 5 formed above the intermediate plug 4, a vent tube 6 so disposed as to allow the pellet chamber 2 to communicate with the upper chamber 5 while penetrating through the intermediate plug 4, an upper vent hole 7 and a lower vent hole 8 formed in upper and lower two stages in such a manner as to penetrate through the cladding tube 1 located at the upper chamber 5, a sodium inflow port 9 so formed as to open to the upper surface of the intermediate plug 4, and a sodium introduction tube 10 so formed as to extend from the sodium inflow port 9 to the inside of the pellet chamber 3 while penetrating through the intermediate plug 4. The control element as shown in FIG. 1 is disposed and immersed in sodium coolant in the primary cooling system of a fast reactor in a longitudinal direction as shown in the drawing. The construction of this control element is similar to that of the conventional diving bell type control rod of the helium bond type in that the pellet chamber, the intermediate plug, the upper chamber, the vent tube and the vent hole are provided. However, the control element of the present invention is constituted by adding the upper vent hole 7 and the lower vent hole 8 formed in upper and lower two stages as the vent hole, the sodium inflow port 9 opening to the upper surface of the intermediate plug 4 and the sodium introduction tube 10 extending from the sodium inflow port 9 into the pellet chamber 3 while penetrating through the intermediate plug 4. The control element is shaped into the sodium bond type by merely adding such simple components. Since the control element is constituted into the sodium bond type, the gap between the cladding tube 1 and the pellet 2 can be enlarged, so that ACMI can be avoided for a long time and service life of the control rod can be improved. The reason why the vent holes 7 and 8 are disposed in the upper and lower two stages is that the helium gas is allowed to escape to the outside from the upper vent hole 7 while sodium can flow in from the lower vent hole 8. If the vent hole is disposed in only one of the upper and lower stages, the internal pressure due to the helium gas restricts the inflow of sodium into the pellet chamber 3. The sodium inflow port 9 and the sodium introduction tube 10 are disposed so as to let sodium inside the upper chamber 5 flow down into the pellet chamber 3. The sodium introduction tube 10 is formed so that the lower end thereof extends downward from the lower end surface 6A of the vent tube 6. This is because the helium gas generated from the pellet 2 during use can be introduced into the vent tube 6 from the lower end surface 4A of the intermediate plug 4 but is prevented from entering the sodium introduction tube 10. In short, the sodium charging route comprises sodium outside the control element.fwdarw.lower vent hole 8.fwdarw.upper chamber 5.fwdarw.sodium inflow port 9.fwdarw.sodium introduction tube 10.fwdarw.pellet chamber 3.fwdarw.vent tube 6. On the other hand, the helium discharging route during use comprises the pellet chamber 3.fwdarw.vent tube 6.fwdarw.upper chamber 5.fwdarw.helium space 12.fwdarw.upper vent hole 7.fwdarw.sodium outside the control element (indicated by arrow in FIG. 1). In this way, the sodium charging route and the helium discharging route are mutually independent in the control rod of the present invention. Accordingly, in comparison with the case where charging of sodium and discharging of helium are effected by one route, the present invention can make the B.sub.4 C powder dispersed in sodium inside the control element remain in the control element and can prevent its outflow outside the control element. Further, because the sodium charging route is formed so that sodium flows from the upper portion to the inside and because there is no opening at the lower part of the control element, the outflow of the B.sub.4 C powder outside the control element can be prevented. Since the present invention has the sodium charging function, it can drastically reduce the length of the vent tube 6 in comparison with the diving bell type control rod of the helium bond type which prevents intrusion of sodium into the pellet chamber by the elongated vent tube (compare the length of vent tube 6 shown In FIG. 1 with that of the vent tube 53 shown in FIG. 4). Reference numeral 11 denotes an upper end plug and reference numeral 12 denotes a helium space. The lower end of the control element is provided with a lower end plug (not shown). The control rod is produced by bundling a plurality of control elements shown in FIG. 1. In the diving bell type control rod equipped with the sodium inflow port and including the control elements having the construction described above, sodium is charged and helium is discharged in the following way. During assembling of the control element, the upper and lower vent holes 7 and 8 are sealed by a solder seal (not shown) and helium is enclosed in the control element. When this control element is immersed in sodium coolant of the fast reactor, the solder seal is molten by the heat of sodium, so that sodium coolant flows into the upper chamber 5 from the lower vent hole 8 while the helium gas in the upper chamber 5 previously enclosed during assembling is emitted from the upper vent hole 7 outside the control element. Thus sodium flows into the upper chamber 5. Next, sodium flows down into the pellet chamber 3 from the sodium inflow port 9 through the sodium introduction tube 10 due to the pressure difference between the upper vent hole 7 and the lower vent hole 8. Sodium in the pellet chamber 3 then rises inside the vent tube 6 up to the liquid level in the upper chamber 5 outside the vent tube 6. Sodium in the upper chamber 5 and the vent tube 6 attains a free liquid level of the level A. As sodium flows in this way, the major proportion of helium enclosed in the cladding tube 1 at the time of assembling is discharged outside the control element through the route comprising the pellet chamber 3.fwdarw.vent tube 6.fwdarw.helium space 12.fwdarw.upper vent hole 7. As described above, the inside of the control element, that is, the upper chamber 5, the pellet chamber 3, the vent tube 6 and the gap between the pellet 2 and the cladding tube 1, are filled with sodium. The helium gas generated from the B.sub.4 C pellet 2 during use enters the vent tube 6 from the lower end surface 4A of the intermediate plug 4 and is further discharged from the upper vent hole 7 outside the control element. Because the lower end of the sodium introduction tube 10 extends below the lower end surface 6A of the vent tube 6, the helium gas hardly enters the sodium introduction tube 10. As being understood from the foregoing, in the diving bell type control rod equipped with the sodium inflow port of the present invention, sodium flows into the upper chamber from the lower vent hole, and sodium inside the upper chamber flows down into the pellet chamber through the sodium inflow port and the sodium introduction tube, and rises in the vent tube. In this way, the pellet chamber is filled with sodium. During this charging of sodium, the helium gas enclosed in the cladding tube is discharged outside from the upper vent hole through the vent tube. The helium gas generated from the B.sub.4 C pellet during use does not enter the sodium introduction tube because the sodium introduction tube extends below the lower end surface of the vent tube, but is discharged outside through the vent tube and the upper vent hole. Accordingly, the control element of the present invention provides the following effects. Since the control element is provided with the sodium charging function and attains the sodium bond type, it can retard the time of generating ACMI and can drastically prolong service life. Moreover, because the present invention can provide the diving bell type control rod of the helium bond type, which has attained proven performance and has had high reliability in safety in the past, with the sodium charging function without a drastic change of the construction, the present invention can produce the control element having high reliability at a low production cost. When the control rod is loaded into the reactor, sodium is allowed to flow and is charged from the lower vent hole disposed at the upper part of the control element. Therefore, the outflow of the boron carbide powder from the lower part of the control element into the cooling system can be prevented. Sodium is charged through the sodium introduction tube while helium is discharged through the vent tube so that the sodium charging route and the helium discharging route are mutually independent. Therefore, the boron carbide powder dispersed into sodium in the control element can be retained inside the control element. In the conventional diving bell type control rod of the helium bond type, further, intrusion of sodium into the pellet chamber is prevented by increasing the length of the vent tube whereas in the present invention, the control element is provided with the sodium charging function. Therefore, the length of the vent tube can be drastically reduced, and the overall length of the control rod can be reduced. |
047708425 | abstract | The present invention is a multimode sensor system that transmits power down a common bus coaxial cable typically using an alternating current power source. Each remote unit connected to the coaxial cable and through an isolation transformer converts the alternating current power to direct current power for an integrated circuit bus interface. The interface is connected to the sensors. The interface is externally pin programmable to provide a carrier at a frequency for a channel assigned to the remote unit. The carrier is provided by a ripple counter producing a frequency divided signal compared to a fixed reference frequency, where the result of the comparison controls a voltage controlled oscillator. When plural low frequency analog signals are to be transmitted over the common bus, an on-chip multiplexer multiplexes the signals to an off-chip, external analog-to-digital converter. The analog-to-digital converter loads an on chip parallel to serial register that applies each bit of the sampled signal serially to an on chip Manchester encoder. The encoder modifies the input voltage of the voltage controlled oscillator operating at the carrier frequency. The oscillator signal is applied to the coaxial cable. Receivers at the end of the coaxial cable are each tunable to a designated carrier frequency and each decode the respective encoded signal. If a high frequency analog signal is supplied to the voltage controlled oscillator, the carrier is modulated by the high frequency signal and the receiver demodulates the signal. The integrated circuit is arranged so that the digital circuitry is generally isolated from the analog circuitry so noise immunity is enhanced. |
description | The invention relates to a particle-optical appliance provided with an objective lens and with aberration-correcting means for correcting lens errors of the objective lens, which aberration-correcting means consists of: a first group of optical elements, consecutively consisting of a first, a second and a third quadrupole lens and a first octupole; a second group of optical elements, consecutively consisting of a second octupole and a fourth, a fifth and a sixth quadrupole lens; and at least one third octupole, placed outside both groups of optical elements, whereby the first and the second octupole and the third and the fourth quadrupole lens are placed between the first and the second quadrupole on the one hand and the fifth and the sixth quadrupole on the other hand,in which the quadrupole lenses determine the paths of electrically charged particles in the aberration-correcting means in such a manner as to cause imaging of octupoles upon one another. Such an appliance is known from US patent application No. US 2004/0004192 A1. The aberration-correcting means (aberration corrector) described in this document comprise a first group of optical elements and a second group of optical elements. In the direction of ray propagation (see the reference numerals in the cited US document), the first group of optical elements consecutively consists of two quadrupoles 51 and 52, a combination of a quadrupole and an octupole 61, and a quadrupole 53. In the direction of ray propagation, the second group of optical elements consecutively consists of a quadrupole 55, a combination of a quadrupole and an octupole 62, and two quadrupoles 56 and 57. A further octupole 64 can be placed prior to the above-mentioned elements; alternatively, this octupole 64 can be omitted and an octupole 63 can be placed behind the above-mentioned elements. In total, this known aberration corrector thus consists of eight quadrupoles and three octupoles. Using the aberration corrector described in the cited US document, it is possible to completely correct the third-order spherical aberration of the objective lens, and also to correct all fifth-order geometric image errors. Moreover, the cited US document sets forth that it is possible to additionally correct the axial chromatic aberration of first order. The invention aims to provide a particle-optical appliance provided with an aberration corrector made up of quadrupoles and octupoles, which aberration corrector has a simpler construction than the aberration corrector described in the cited US patent document, whereby at least the same aberration-correcting power is maintained. To this end, the particle-optical appliance according to the invention is characterized in that: in a first axial plane, the first and the second octupole are not imaged upon one another, and the second and the third octupole are imaged upon one another; in a second axial plane perpendicular to the first axial plane, the first and the second octupole are not imaged upon one another, and the first and the third octupole are imaged upon one another; and an axial beam in the first axial plane passes through the axial point of the first octupole and in the second axial plane passes through the axial point of the second octupole, as a result of which third-order lens errors of the objective lens are corrected, and fifth-order lens errors of the objective lens are, at the least, minimized. The cited US document sets forth that all octupoles must be imaged upon one another, both in the x-z plane and in the y-z plane. The invention is based upon the insight that this is an overly stringent demand, which can be softened. Softening said overly stringent demand is made possible by the fact that an axial ray in the first axial plane is sent through the axial point of the first octupole and in the second axial plane is sent through the axial point of the second octupole. Put another way: with the aid of quadrupoles, a first line focus is formed in the first octupole and a second line focus—perpendicular to the first one—is formed in the second octupole. The softened demand now requires that, in a first axial plane, the first and the second octupole are not imaged upon one another and the second and the third octupole are imaged upon one another, and, in a second axial plane perpendicular to the first axial plane, the first and the second octupole are not imaged upon one another, and the first and the third octupole are imaged upon one another. By somewhat softening said overly stringent demand in this manner, full correction of said aberrations of the objective can still occur, as a result of which, in the aberration corrector according to the invention, one can suffice with just six quadrupoles instead of eight. In this manner, not only are construction costs of the corrector reduced, but the dimensions thereof can also reduce, and, as a result of the smaller number of components, the excitation adjustment and the alignment within the particle-optical appliance also become less complicated. In an embodiment of the particle-optical appliance according to the invention, the quadrupole field of the third quadrupole lens and the octupole field of the first octupole overlap one another at least partially, and the quadrupole field of the fourth quadrupole lens and the octupole field of the second octupole overlap one another at least partially. In this manner, it is possible to embody said quadrupoles and octupoles as one physical whole, as a result of which, in the case of a magnetic multipole, for example, a single iron circuit will suffice, as will a single electrical power supply unit. Moreover, as a result of the spatial coincidence of said quadrupoles and octupoles, space is saved, as a consequence of which the construction of the particle-optical apparatus can be more compact. In another embodiment of the particle-optical appliance according to the invention, the third octupole is located at that side of the aberration-correcting means at which the objective lens that is to be corrected in the particle-optical appliance is not located. So as to achieve an optimal correction, it is generally desirable in the case of quadrupole-octupole correctors that the third octupole be imaged onto the coma-free plane of the objective to be corrected. Now, if the third octupole is located at that side of the corrector at which the objective lens is located, then a transfer lens will be necessary between this octupole and the objective, so as to achieve the image referred to. However, if the third octupole is located at that side of the corrector at which the objective lens that is to be corrected in the particle-optical appliance is not located, then the objective can be placed at the other side of the corrector, and a transfer lens is thus unnecessary. In yet another embodiment of the particle-optical appliance according to the invention, the third octupole is divided into a first portion and an equal second portion by a cross-section perpendicular to the optical axis, which portions are respectively located on opposite sides of both groups of optical elements, and a plane of mirror symmetry perpendicular to the optical axis is present in such a manner that, when mirrored with respect to said symmetry plane, the positions of the three quadrupoles and the octupole of the first group, and the first portion of the third octupole, yield the locations of the three quadrupoles and the octupole of the second group, and of the second portion of the third octupole, whereby the excitations of the quadrupoles of the first group are opposite to those of the corresponding quadrupoles of the second group. With the aid of these measures, a number of lens errors of the fifth order are corrected. These fifth-order lens errors can be represented in a manner known per se, according to a systematic classification; see, in this context, the article by M. Haider et al. in Ultramicroscopy 81, (2000), pp. 163-175. In this classification, all axial geometric lens errors of the third and the fifth order are divided into various groups, in which the coefficients are indicated by the letters A, C, D and S. The coefficients are further provided with an index that indicates the order of the relevant lens error. For example, in this classification system, the generally known coefficient of the third-order spherical aberration is indicated by C3. The coefficients of the lens errors that are corrected using the above-mentioned measures are indicated in said classification by A5 and S5; they can be respectively described as the fifth-order aberration with six-fold symmetry and the fifth-order aberration with two-fold symmetry. In this manner, these lens errors are therefore all made equal to zero. In yet another embodiment of the particle-optical appliance according to the invention, the third and the forth quadrupole lens are each embodied as a combination of magnetostatic and electrostatic quadrupoles. By employing these measures, one achieves a situation whereby the axial chromatic lens error of the first order and the first degree (i.e. the chromatic lens error that is proportional to (ΔU/U)1, in which U is the acceleration voltage of the charged particles) is made equal to zero, and whereby non-axial chromatic lens errors are made relatively small. An axial lens error should be interpreted as being a lens error whose magnitude does not demonstrate a proportionality to the distance to the optical axis. (An example of an axial lens error is the previously mentioned third-order spherical aberration with coefficient C3; an example of a non-axial lens error is the third-order coma, whose magnitude is proportional to the distance r to the optical axis.) Moreover, by employing these measures, one also achieves a situation whereby the axial chromatic errors of degree 2—which in the case of a conventional corrector would be strongly increased by this corrector—are reduced once again in the present corrector as a result of the above-mentioned measures. In a further embodiment of the particle-optical appliance according to the invention, a further quadrupole lens from the first group of optical elements and a further quadrupole lens from the second group of optical elements are each embodied as a combination of a magnetostatic and an electrostatic quadrupole. The technical effect of these measures is that it is possible to make further chromatic aberrations exactly equal to zero, namely either the chromatic magnification error (Ccm) or the axial chromatic error of degree two (Ccc). Although it is possible in this manner and with these measures to make, according to choice, one of both errors exactly equal to zero and to reduce the other, it is hereby generally not possible to simultaneously make both exactly equal to zero. In yet a further embodiment of the particle-optical appliance according to the invention, a transfer lens system is placed between the corrector and the objective to be corrected, which system causes the particle rays to pass through a point of intersection in the optical axis, at the location of which point of intersection a seventh quadrupole is placed. It should be pointed out that a transfer lens system should also be interpreted as referring to a single lens. The technical effect of said measures is that, once again, it is hereby possible to make further chromatic aberrations exactly equal to zero, namely either the chromatic magnification error (Ccm) or the axial chromatic error of degree two (Ccc). In this case also, it is generally not possible, using these measures, to simultaneously make both these errors exactly equal to zero. In yet a further embodiment of the particle-optical appliance according to the invention, the three quadrupole lenses from the first group of optical elements and the three quadrupole lenses from the second group of optical elements are all embodied as a combination of magnetostatic and electrostatic quadrupoles, and the first, the second, the fifth and the sixth quadrupole are also embodied to be achromatic. Using these measures, three types of lens errors can be corrected, namely: (1) The axial chromatic lens error of the first order and the second degree, which is indicated by Ccc; (2) The geometric-chromatic mixed axial lens errors of the third order and the first degree. These mixed lens errors consist of three components, namely a component that is circularly symmetric about the optical axis, indicated by C3c; a component that demonstrates two-fold symmetry about the optical axis, indicated by S3c; and a component that demonstrates four-fold symmetry about the optical axis, indicated by A3c; and (3) The non-axial chromatic lens error of the first order and the first degree, indicated by Ccm.It should be pointed out that, using the above-mentioned measures, of said three types of lens error, two can generally be simultaneously made equal to zero, whereby the third—although made much smaller—does not become exactly equal to zero. In yet another embodiment of the invention, at least three further octupoles are added, which are placed at the locations of the first, the second and the third octupole, respectively, which first, second and third octupoles are even octupoles and which first, second and third further octupoles are uneven octupoles, each of which uneven octupoles, as a result of a cross-section perpendicular to the optical axis, consists of a first and a second portion, in which the ratio of the excitations of the first and the second portion of each uneven octupole is such that the contribution of the uneven octupoles to the third-order axial aberrations is equal to zero, and in which the total excitation of all uneven octupoles is such that the anisotropic coma of the combination of the aberration-correcting means and the objective lens to be corrected is equal to zero. Because the three further octupoles can be of relatively small optical power, it is easily possible in this manner to achieve a correction of the anisotropic coma. In this paragraph, an embodiment will first be given pertaining to the making of a paraxial design of a corrector according to the invention. So as to avoid rendering the calculations pertaining to the making of a corrector design with six quadrupoles and three octupoles extremely complicated and/or confused, one can adopt a number of simplifying initial conditions. Such initial conditions can, in principle, be freely chosen, whereby the number of such initial conditions must naturally lie within the degrees of freedom offered by the design of corrector. A first approximation of the final design makes use of (and is thus valid for) the paraxial propagation of rays in the corrector. Such initial conditions may, for example, be: (1) One chooses a corrector that is telescopic, i.e. a ray incident upon the corrector parallel to the optical axis will also emerge from the corrector parallel to the optical axis; (2) The six quadrupoles and two of the three octupoles are positioned w.r.t. one another on the optical axis in such a manner that a plane of mirror symmetry is present (perpendicular to the optical axis), which, in this case, means that, when mirrored w.r.t. that symmetry plane, the locations of three of the six quadrupoles yield the locations of the remaining three quadrupoles, and that, when mirrored, the location of one of the two octupoles yields the location of the other of the two octupoles; (3) The excitations of the six quadrupoles are anti-symmetric w.r.t. the symmetry plane, which is to say that, in the case of an electrostatic embodiment of the quadrupoles, a positive (negative) pole on one side of the symmetry plane corresponds to a negative (positive) pole on the other side of the symmetry plane, and that, in the case of a magnetostatic embodiment of the quadrupoles, a north pole (south pole) on one side of the symmetry plane corresponds to a south pole (north pole) on the other side of the symmetry plane. Moreover, one would naturally also like the conditions according to the current invention to be satisfied, i.e. (1) that in a first axial plane, further referred to as the x-z plane, the first and the second octupole are not imaged onto one another, but the second and the third octupole are, and (2) that in a second axial plane perpendicular to the first axial plane, further referred to as the y-z plane, the first and the second octupole are not imaged onto one another, but the first and the third octupole are, and (3) that an axial ray in the x-z plane passes through the axial point of the first octupole and in the y-z plane passes through the axial point of the second octupole. The above-mentioned initial conditions and requirements result in five equations, as will be demonstrated hereunder. The ray propagation in an optical system with quadrupoles is determined by means of two independent rays in the x-z plane and two independent rays in the y-z plane. As usual, the independent rays are chosen to be the co-called axial ray and the field ray. In this context, an axial ray is understood to be a ray that, as regards a sample to be investigated in the particle-optical appliance, intersects that sample in the axial point of the sample, and a field ray is understood to be a ray that intersects the sample outside the axial point of the sample. The positive direction of the optical axis is indicated by z; the course of an axial ray in dependence upon z in the x-z plane is indicated by xa(z), that of a field ray in the x-z plane by xf(z), that of an axial ray in the y-z plane by ya(z), and that of a field ray in the y-z plane by yf(z). As is generally known to persons skilled in the relevant art, the octupoles in quadrupole-octupole correctors have no effect on the paraxial ray propagation in the corrector. It is therefore only the quadrupoles that determine the paraxial ray propagation in the corrector. By assuming the above-mentioned mirror symmetry, it holds that two independent paraxial rays in front of the mirror plane in the x-z plane (y-z plane) demonstrate the same course as those two rays behind the mirror plane in the y-z plane (x-z plane). In the form of a formula, this can be expressed as follows: ya(z)=xa(—z), y′a(z)=−x′a(−z), yf(z)=−xf(−z) and y′f(z)=x′f(−z). In these expressions, x′a(z), y′a(z), x′f(z) and y′f(z) are the derivatives with respect to z of the respective rays, as a function of z. From these expressions, the following four relations are obtained at the location of the symmetry plane with position z=0: xa(0)=ya(0), x′a(0)=−y′a(0), x′f(0)=y′f(0) and xf(0)=−yf(0). In these last four relations, x′a(0), x′f(0), y′a(0) and y′f(0) are the respective slopes of the rays xa(z), xf(z), ya(z) and yf(z) at the location of the symmetry plane. One must realize in this instance that, of these four relations, only three are independent, because one must also satisfy the condition that the determinant of the transfer matrix be equal to 1. As a result of this dependence, one of the four relations set forth above can be omitted, e.g. xf(0)=−yf(0), so that only three mutually independent relations remain. Consequently, so as to arrive at the five equations previously referred to, two further equations are required. To this end, one must first satisfy the stipulations according to the present invention that 1) an axial ray in the first axial plane (i.e. the x-z plane) passes through the axial point of the first octupole, and that 2) an axial ray in the second axial plane (i.e. the y-z plane) passes through the axial point of the second octupole. Satisfying one of these stipulations gives rise to an equation; for example, satisfying stipulation 1) gives rise to the equation xa(0)=x′a(0)d. This latter equation is obtained based upon the insight that satisfying these requirements is equivalent to the situation whereby the field rays are refracted in such a manner by the first three quadrupoles that, as a result, a line focus is formed (perpendicular to the direction of the line focus in the x-z plane) in the middle of the same octupole; as a result, the relation xa(0)=x′a(0)d applies. As a result of the assumed symmetry (see the above-mentioned starting conditions (2) and (3)), satisfying one of the stipulations (in this case, therefore, the above-mentioned condition 1)) results in the other stipulation being satisfied (above-mentioned condition 2)). In this manner, satisfying stipulations 1) and 2) leads to just one equation, namely the above-mentioned equation xa(0)=x′a(0)d, which forms the fourth equation. Secondly, one must also satisfy the stipulations according to the invention that 3) in a first axial plane (i.e. the x-z plane) the first and the second octupole are not imaged upon one another, and the second and the third octupole are imaged upon one another, whereby the relevant ray is the field ray in the x-z plane xf(z), and that 4) in a second axial plane (i.e. the y-z plane) perpendicular to the first axial plane, the first and the second octupole are not imaged upon one another, and the first and the third octupole are imaged onto one another, whereby the relevant ray is the field ray in the y-z plane yf(z). Satisfying one of these stipulations gives rise to an equation; for example, satisfying stipulation 4) leads to the equation yf(0)=y′f(0)d. As a result of the symmetry already referred to above, satisfying stipulations 3) and 4) leads to the one equation referred to above, viz. yf(0)=y′f(0)d, which forms the fifth equation. In summary, the five equations that apply at the location of the symmetry plane can be expressed as follows:xa(0)=ya(0) (1)x′a(0)=−y′a(0) (2)x′f(0)=y′f(0) (3)xa(0)=x′a(0)d (4)yf(0)=y′f(0)d (5) So as to arrive at a design for an aberration corrector according to the invention based on these five equations, the following quantities must be determined: the z-position of each of the four quadrupoles (3 parameters), and the thickness in the z-direction of each of the three quadrupoles (3 parameters), and the excitation of each of the three quadrupoles (3 parameters), and the z-position of the octupole that is placed at a distance d from the symmetry plane, i.e. the value of d (1 parameter), and the desired z-position of the third octupole (1 parameter). So as to arrive at a design, a total of 3+3+3+1+1=11 parameters must therefore be determined; the equations (1) to (5) set forth above must thereby be satisfied, which means that, in designing a corrector, 11−5=6 degrees of freedom are still available. Very many paraxial designs are therefore possible and, so as to maintain a good overview of the design process, one can initially adopt a simplified starting scenario and can use the design resulting therefrom as a starting scenario for the complete, non-simplified design process. As the simplified starting scenario, one may, for example, choose a thin lens approximation for the quadrupoles, i.e. one initially chooses a thickness of zero. As a result, these three parameters do not have to be determined, so that the number of degrees of freedom is reduced from six to three. This means that, if a proper choice of the value of these last three parameters is made in advance, a set of five (non-linear) equations in five variables has to be solved. The value of these three parameters to be chosen in advance may be: the distance zQ1 of the first quadrupole to the symmetry plane M is 80 mm, the distance zQ2 of the second quadrupole to the symmetry plane M is 60 mm, and the distance zQ1 of the first octupole to the symmetry plane M is 60 mm. The above-mentioned set of five equations can now be solved in a manner known per se, e.g. with the aid of the so-called multi-dimensional Newton-Raphson method. In order to apply this method, a properly chosen set of initial values is required, e.g. the distance zQ3 of the third octupole to the symmetry plane=115 mm, the distance zQ3 of the third quadrupole to the symmetry plane=35 mm and, further, three excitations for the quadrupoles, all of which are equal and have alternating sign. With these starting assumptions, and without solving the above-mentioned five equations, a course of paraxial paths as depicted in FIG. 1a would be obtained. In that figure (and in FIGS. 1b and 1c), the axial ray in the x-z plane xa is depicted by the solid bold line 2, the field ray in the x-z plane xf is depicted by the dot-dashed line 4, the axial ray in the y-z plane ya is depicted by the thin dashed line 6, and the field ray in the y-z plane yf is depicted by the interrupted dashed line 8. Also depicted in these figures are the positions of the first quadrupole Q1, the second quadrupole Q2 and the third quadrupole Q3, and the position of the first octupole O1, the second octupole O2, and the third octupole O3 that is divided into two equal portions O3a and O3b. By applying the iterating Newton-Raphson method, the following solutions are found: the distance zO3a of the portion O3a of the third octupole to the symmetry plane=120 mm, the distance zQ3 of the third quadrupole to the symmetry plane=30 mm and, further, three excitations for the quadrupoles such that the course of paraxial paths obtained as a result thereof is as depicted in FIG. 1b. One can choose a similar approach in the case of an assumption that the lens thickness is not equal to zero. As an initial condition, a thickness of 10 mm is now assumed for all quadrupoles. The iterative Newton-Raphson method is now applied again to this configuration, which finally leads to a course of paraxial paths as depicted in FIG. 1c. In this figure, the middle of the quadrupoles is depicted. It is hereby found that the distance zO3 of the third octupole to the symmetry plane is 115 mm and that the distance ZQ3 from the middle of the third quadrupole to the symmetry plane is 34 mm. The paraxial design of the corrector is thus completed. (a) For TEM, STEM and SEM in General In order to arrive at a practical design of corrector starting out from the paraxial design, a number of further requirements have to be met. These requirements lead, on the one hand, to conditions regarding the error-correcting power and, on the other hand, to practical conditions regarding the application of the corrector, particularly in a specific particle-optical appliance, such as a Transmission Electron Microscope (TEM), a Scanning Electron Microscope (SEM), or a Scanning Transmission Electron Microscope (STEM). In order to satisfy said requirements/conditions, it is sometimes desirable to assign to the six freely chosen parameters (the six degrees of freedom) in the description of the paraxial design set forth above an initial value that is different from the values that are mentioned in the paraxial design above. In this manner, one can satisfy all sorts of requirements as set forth above, e.g. (1) keeping to a low value the signal-to-noise ratio in the excitation current and/or excitation voltage of the optical elements, (2) for a given bore value, preventing magnetic saturation of the iron circuits of the optical elements, or keeping electrostatic elements below the electrical breakdown voltage, (3) assigning values to the geometric aberration coefficients C3 (=the generally known 3rd-order spherical aberration) and C5 (=the fifth-order spherical aberration) in such a manner that these lens errors compensate one another, and (4) reducing the seventh-order axial aberrations to a sufficient extent. It should be pointed out that the consideration as to whether or not to electromagnetically excite the quadrupoles in the corrector so as to correct chromatic aberration, and whether or not to adjust these quadrupoles so as to be exactly achromatic, is dependent upon the area of application of the corrector. One can distinguish two principal areas of application where this is concerned, namely a first area of application involving high-voltage TEM (HV TEM) and (high-voltage) STEM (HV STEM), and a second area of application involving SEM and low-voltage TEM (LV TEM). In the first area of application (HV TEM and HV STEM), the quadrupoles Q1, Q2, Q5 and Q6 are all embodied to be exclusively magnetic or exclusively electric; of themselves, they are therefore not achromatically embodied. Quadrupoles Q3 and Q4 are both electromagnetically embodied, and their chromatic state is such that they demonstrate a chromatic deviation that is opposite to that of the objective lens to be corrected, as a result of which the axial chromatic aberration thereof is corrected. In the second area of application (SEM and LV TEM), all quadrupoles are electromagnetically embodied. The quadrupoles Q1 and Q6 are thereby of themselves exactly achromatic. The chromatic state of the quadrupoles Q2 and Q5 is such that they deviate to a very small extent from an achromatic state, so that the condition Ccmx=Ccmy=0 is satisfied. The chromatic state of the quadrupoles Q3 and Q4 is such that they demonstrate a chromatic deviation that is opposite to that of the objective lens to be corrected, as a result of which the axial chromatic aberration thereof is corrected (b1) The Definitive Design for High-Voltage TEM and STEM Specifically In the case of the definitive design specifically for a TEM, some additional requirements can be formulated, viz. (5) reducing the fifth-order coma to a sufficient extent, and (6) reducing the chromatic magnification error Ccm to a sufficient extent. The importance of satisfying requirement (3) lies in the fact that, in this manner, thin samples that can be regarded as phase objects still maintain a sufficient Contrast Transfer Function in images with extremely high resolution. In the case of the definitive design specific to a SEM or a STEM, it is true to say that satisfying requirements (5) and (6) is not of primary importance, but a TEM design in which those requirements are satisfied can be used without drawbacks in the case of a STEM. It is therefore easy to use this design both in the case of a TEM and a STEM. Satisfying requirement (6) is of particular importance in the case of a TEM, in which acceleration voltages of the order of magnitude of 300 kV are commonplace. In that case, for the purpose of correcting chromatic aberration, at any rate the third and the fourth quadrupole are embodied as electromagnetic elements, but, because of the high acceleration voltage, the first, second, fifth and sixth quadrupole are preferably embodied to be purely magnetic. However, this can have consequences as regards the chromatic magnification error, which can be explained as follows. Between the corrector and the objective to be corrected, a transfer lens system is placed, which system can be embodied to have a quadrupole lens. If no quadrupole lens is present therein, the chromatic magnification error cannot be made exactly equal to zero. If a quadrupole lens is present therein, one can choose between two situations: one can make the chromatic magnification error exactly equal to zero but, in that case, the third-order isotropic coma will not be equal to zero, or one can make the third-order isotropic coma exactly equal to zero but, in that case, the chromatic magnification error will not be equal to zero. (The lens errors that do not remain exactly equal to zero maintain a small residual value in this case). One therefore has a choice between a full correction of the chromatic magnification error and a full correction of said third-order isotropic coma, depending on the area of application of the corrector. In performing the actual design process, use is also made of the insight that still further improvements in the optical properties of the design can be achieved by additionally applying octupoles of relatively low optical power (or rather: of relatively little influence on the electrons) at the location of the first, the second, the fifth and the sixth quadrupole; these four extra octupoles must also satisfy the symmetry requirements w.r.t. the plane of mirror symmetry. They are applied inter alia to correct the intrinsic third-order aberrations of the associated quadrupoles. If the transfer lens system referred to earlier is present, a further degree of freedom is obtained in the design, viz. the intrinsic magnification of this transfer lens system. During the design process, for the purpose of calculating the excitations of all octupoles, one maintains the requirement that the third-order axial aberrations and the third-order isotropic coma (in the event that the quadrupole lens in the transfer lens system is not active) be reduced to zero. The aberration coefficients concerned (eight in principle, but, as a result of the mirror symmetry, only four are independent) are linearly dependent upon the octupole excitations, and are therefore described using four linear equations. The total number of octupoles is formed in this instance by the four relatively strongly excited octupoles and the four octupoles of relatively little influence. As a result of the mirror symmetry, these eight octupoles thus also have four degrees of freedom. The octupole excitations to be determined for the total of eight octupoles can therefore be found from four linear equations with four unknowns. In addition, one has the possibility during the design process, at locations where the zero crossings of the rays in the corrector should lie in the relatively strongly excited octupoles, not to situate these zero crossings exactly in the middle of those octupoles, but rather at a somewhat deviated position, though still within the z-position of the iron circuit or of the electrodes of the octupoles, and thus within the effective region of the octupole fields. This possibility yields a further three degrees of freedom. Execution of this design process occurs with the aid of a simulation program in which all sorts of parameters can be set according to desire. Such a simulation program must satisfy a number of requirements, the most important of which are: the simulation program must be able to simulate the behavior of quadrupoles with a finite thickness, and the attendant fringing fields, and the simulation program must be able to simulate all aberrations of the quadrupoles and of the octupoles with a finite thickness, and the attendant fringing fields, and the simulation program should preferably contain a routine for solving n equations with n unknowns (e.g. according to the Newton-Raphson method), in which n is at least equal to five, so as to be able to tackle the five equations (1) to (5) that apply at the position of the symmetry plane in the paraxial design, and the simulation program should preferably be able to calculate the above-mentioned octupole excitations, which requires a routine for solving four equations in four unknowns. Such a simulation program can, for example, be obtained by modifying an existing, commercially available program so as to satisfy the above-mentioned requirements. (b2) The Definitive Design for SEM or Low-Voltage TEM Specifically The definitive design specifically for a SEM or a low-voltage TEM is basically the same as that for high-voltage TEM, whereby an extra requirement must be formulated as regards two quadrupoles, namely Q1 and Q6 or Q2 and Q5. This is because, when the quadrupoles Q1, Q2, Q5 and Q6 are all made exactly achromatic, a (small) chromatic magnification error will usually arise, indicated by Ccmx and Ccmy (for the x-z plane and the y-z plane, respectively). So as to make this chromatic magnification error exactly equal to zero, the quadrupoles Q2 and Q5 or Q1 and Q6 must be made somewhat achromatic in equal measure, with a deviation from the magnetic excitation that is of the order of magnitude of 1% of the total magnetic excitation. (c1) The Course of the Design Process in the Case of STEM or High-Voltage TEM The design process now proceeds along the following lines: If one considers as given quantities the acceleration voltage of the electrons and the optical properties of the objective lens to be corrected, then a relatively large number of degrees of freedom remains for use in the actual design process. A distinction can be made between two groups of degrees of freedom, viz. those degrees of freedom for which values must be chosen at the start of the design process, and those degrees of freedom whose values must be determined during the design process. The first group of degrees of freedom is formed by: The six degrees of freedom described in the paragraph “The paraxial design”, which are left over from the original eleven degrees of freedom after satisfying the five equations that apply at the location of the symmetry plane; and The optical power of the third and fourth quadrupoles, which, for the purpose of correcting the chromatic aberration, are embodied as electromagnetic quadrupoles. The electric field strength is thereby determined as follows: starting with the paraxial design with only magnetic excitation, the paraxial excitation is augmented by an extra magnetic excitation M′ and an electrostatic field strength E whose total value is such that the contribution of M′+E to the quadrupole optical power is zero for a nominal energy Uo and that Cc-correction is obtained for the objective. One of the quadrupoles works thereby for the x-z plane and the other quadrupole for the y-z plane. This addition of electric quadrupole field strength yields, in principle, 1 degree of freedom (because of the mirror symmetry). The intrinsic magnification of the transfer lens system similarly yields, in principle, 1 degree of freedom. If, however, for one of these two parameters (electric quadrupole field strength and intrinsic magnification) a value is chosen, then the other parameter can be calculated via the requirement that the total chromatic aberration be zero. This therefore yields a balance of 1 degree of freedom; and The possibility, referred to above in the paragraph (b1) “The definitive design for high-voltage TEM and STEM specifically”, at those locations where the zero crossings of the rays within the corrector must lie within the octupoles, not to situate these zero crossings exactly in the middle of the octupoles but, rather, somewhat deviated therefrom (in general, 4 degrees of freedom, but, as a result of said mirror symmetry, 2 degrees of freedom).In total, this first group therefore yields 6+1+2=9 degrees of freedom. The second group of degrees of freedom is made up of those degrees of freedom whose values have to be determined during the design process. The second group of degrees of freedom is formed by: Those octupole excitations, referred to above in the paragraph “The definitive design for TEM and STEM specifically”, for which the third-order axial aberrations and the isotropic coma become zero. As set forth there, 4 degrees of freedom follow herefrom; and The positions of the first portion and the second portion of the third octupole, which positions should be chosen in such a manner that the lens error indicated by D5 (the axial fifth-order aberration with four-fold symmetry) becomes zero. As a result of the mirror symmetry, this yields 1 degree of freedom; and Optionally: as referred to in the paragraph (b1) “The definitive design for high-voltage TEM and STEM specifically”, the excitation of the quadrupole lens in the transfer lens system so as make the chromatic magnification error Ccmx, Ccmy equal to zero. This optionally yields 1 degree of freedom.In total, this second group therefore yields 4+1=5 (optionally 6) degrees of freedom, so that the design process for TEM and STEM has a total of 9+5=14 (optionally 9+6=15) degrees of freedom.(c2) The Course of the Design Process in the Case of SEM or Low-Voltage TEM The course of the design process in the case of a SEM or a low-voltage TEM is basically the same as that for a TEM, whereby it should be understood that the extra requirements for the quadrupoles Q2 and Q5 or Q1 and Q6 set forth above in the paragraph (b2) “The definitive design for SEM or low-voltage TEM specifically” must be satisfied. In the situation whereby the quadrupoles Q1, Q2, Q5 and Q6 are all initially made exactly achromatic, this therefore means that, in one of said two pairs of quadrupoles Q2 and Q5 or Q1 and Q6, the exactly adjusted achromatic state will be made somewhat chromatic, so as to satisfy Ccmx=Ccmy=0. (d) The Steps in the Design Process for TEM, STEM and SEM (1) A starting value is chosen for the nine parameters of the first group (see the paragraph “The course of the design process in the case of STEM or high-voltage TEM” above). Specifically for SEM or low-voltage TEM, the quadrupoles Q1, Q2, Q5 and Q6 are all initially made exactly achromatic, after which quadrupoles Q2 and Q5 or Q1 and Q6 are made somewhat chromatic, so as to satisfy Ccmx=Ccmy=0; (2) A starting value is chosen for the positions of the first portion (O3a) and the second portion (O3b) of the third octupole (see the paragraph (c1) “The course of the design process in the case of high-voltage TEM and STEM” above); (3) The five equations that apply at the location of the symmetry plane, as referred to in the paragraph “The paraxial design”, are solved; (4) The excitation of all octupoles is determined in such a manner that the third-order axial aberrations and the isotropic coma become zero. As set forth above in the paragraph (b1) “The definitive design for high-voltage TEM and STEM specifically”, these excitations are calculated by solving four linear equations with four unknowns; (5) One now checks if the axial fifth-order aberration with four-fold symmetry (coefficient D5) is equal to zero. If that is not the case, then the starting values referred to in step (2) above are modified, and steps (2) to (5) are repeated as often as necessary to ensure that D5 is zero; (6) All relevant aberrations are determined, and one also checks if the requirements with regard to the electrical power supplies are satisfied. Said relevant aberrations are: the fifth-order spherical aberration (coefficient C5), the fifth-order isotropic coma, the seventh-order aberrations, and the isotropic chromatic magnification errors (coefficients Ccmx and Ccmy). In the case of these aberrations, it is checked whether they have been made sufficiently small. The requirements w.r.t. the electrical power supplies concern the stability, i.e. whether variations in voltage and/or current as a function of time and the signal-to-noise ratio are sufficiently small. If these requirements are not satisfied, then steps (1) to (6) are repeated using modified starting values until the design of corrector satisfies the stipulated requirements. In the event of application in a SEM or a low-voltage TEM, one can also make the aberration coefficients A3c and C3c equal to zero in this manner. Moreover, as a result of the symmetry w.r.t. the mirroring middle plane M, it transpires that S3c=0, so that all mixed (i.e. mixed geometric-chromatic) aberrations of the third order and the first degree are thus equal to zero. The aberration coefficients A3c, C3c and S3c referred to here are defined in analogy to the definitions known from the aforementioned article by M. Haider. The following expression thereby applies: - S 3 = Re ( 1 4 ω 2 ϖ 2 C 3 + ω 3 ϖ S 3 + 1 4 ϖ 4 A 3 ) in which the quantities in this expression correspond to the quantities employed in the relevant expression used by Haider. By incorporating a factor ε=ΔU/U in this expression (U=the acceleration voltage), one obtains the expression for the coefficients of the mixed geometric-chromatic aberrations: - S 3 c = ɛ Re ( 1 4 ω 2 ϖ 2 C 3 c + ω 3 ϖ S 3 c + 1 4 ϖ 4 A 3 c ) in which, by adding an index c to the aberration coefficients, one indicates that one is dealing here with the coefficients of the mixed geometric-chromatic aberrations. FIG. 2 relates to the course of rays in a corrector according to the invention for use in a STEM or a high-voltage TEM. In this figure, the course of axial rays 2 and 6 and of field rays 4 and 8 is depicted in the x-z plane and the y-z plane of the corrector. The axial ray in the x-z plane is thereby depicted by a solid bold line 2, the field ray in the x-z plane by a dot-dashed line 4, the axial ray in the y-z plane by a thin dashed line 6, and the field ray in the y-z plane by the interrupted dashed line 8. The design of the corrector used hereby was obtained according to the above-mentioned paragraph “The steps in the design process for TEM, STEM and SEM”. The locations on the optical axis (the z-axis) of the six quadrupoles Q1 to Q6 are herein depicted, as are the locations on the z-axis of both octupoles O1 and O2, and the locations of the portions O3a and O3b of the third octupole that has been divided into two equal portions. The plane of mirror symmetry is located at position z=0. Moreover, using the reference numerals 28, 30, 32, 34, 36 and 38, the excitations of the quadrupoles Q1, Q2, Q3, Q4, Q5 and Q6 are indicated in the form of the strength of the field on the optical axis. The following values and data pertain to this design: The quadrupoles Q1, Q2, Q5 and Q6 are embodied to be solely magnetic. The quadrupoles Q3 and Q4 are embodied to be electromagnetic. At the locations of the quadrupoles Q1, Q2, Q5 and Q6, magnetic octupoles of relatively low optical power have been added. The portions O3a and O3b of the third octupole that has been divided into two equal portions are imaged onto the coma-free plane of the objective lens. Acceleration voltage: 300 kV. Focal length of the objective lens to be corrected: 2.3 mm. Cc of the objective lens: 1.4 mm. Cs of the objective lens: 1.2 mm. Internal radius of the multipoles: 2 mm. Length of the quadrupoles Q3 and Q4: 56 mm. Length of the octupole portions O3a and O3b: 16 mm. Magnification of the transfer lens system: 1.2 (as a result of which the beam diameter at the entrance to the objective is 1.2 times as large as in the exit plane of the corrector). Octupole portions O3a and O3b are displaced by a distance of 2.92 mm w.r.t. their paraxial position (i.e. the position where the Gaussian rays cross the z-axis), away from the symmetry plane. The zero crossings of the rays xa and yf (ya and xf) in quadrupole Q3 (Q4) are both displaced by a distance of 3.05 mm w.r.t. the middle of that quadrupole, away from the symmetry plane (i.e. they still coincide, but they no longer lie exactly in the middle of the quadrupole).In Table 1 that follows, the aberrations of the combination of the corrector and the objective lens (specifically for a TEM) are depicted. In the table, the aberrations in rows 1 to 5 are indicated using the symbols according to the cited article by Haider et al. The third column relates to the situation whereby the quadrupole lens in the transfer lens system (Quadrupole Field Lens, QFL) is turned off; in the forth column, it is turned on. #QFLoffon1C3, S3, A3 (mm)002C5 (mm)−0.31−0.313S5 (mm)0−1.454D5 (mm)005A5 (mm)006S80 (mm)577S62 (mm)−9−88S44 (mm)−31−309S26 (mm)383910S08 (mm)−5−2.511Sx30 = Sx120−2.312Sy21 = Sy0302.313i Fan0.7 i0.7 i14Sx508415Sx32−42−4616Sx143417Sy41−8−418Sy23434719Sy05−3−320Ccx, Ccy (mm)0021Cccx (mm)71222Cccy (mm)171223Ccmx−3.0024Ccmy3.00In rows 6 to 10 of Table 1, the seventh-order aberration coefficients are indicated; as is evident from the values concerned, these are of the order of magnitude of a few centimeters at most. Rows 11 and 12 indicate the coefficients of the isotropic coma. Row 13 relates to the anisotropic coma; the correction for this will be discussed in what follows. Rows 14 to 19 indicate the coefficients of the fifth-order coma; from the values concerned, it is evident that this group of lens errors is negligible. Row 20 indicates the coefficients of the chromatic aberration in both the x-z plane (Ccx) and the y-z plane (Ccy). Rows 21 and 22 indicate the coefficients of the axial chromatic error of degree two Ccc in the x-z plane (Cccx) and the y-z plane (Cccy) respectively. Rows 23 and 24 indicate the coefficients of the chromatic magnification error (Ccm) in the x-z plane (Ccmx) and the y-z plane (Ccmy) respectively. According to an aspect of the invention, it is possible to correct the anisotropic coma in the case of application in a TEM. This correction can be achieved by locating the various multipoles as in FIG. 2, in which a first octupole O1, a second octupole O2 and a third octupole O3 are present (all magnetostatic), and in which the third octupole is divided into two equal portions O3a and O3b. These four octupoles are of the even type, as will be explained further below. To define an even or an uneven multipole (i.e. a multipole with even or uneven symmetry), the x and y coordinates are expressed in polar coordinates r and φ according to x=r cos φ and y=r sin φ. The azimuthal dependence of the scalar electrostatic potential is now proportional to cos (n φ) for even multipoles and proportional to sin (n φ) for uneven multipoles; for the scalar magnetostatic potential, it is so that the azimuthal dependence is proportional to sin (n φ) for even multipoles and proportional to cos (n φ) for uneven multipoles. Here, n is a whole number, e.g. n=2 for quadrupoles and n=4 for octupoles. So as to achieve the correction of the anisotropic coma, said four even magnetostatic octupoles are modified, which modification can be thought of as occurring as follows: 1) A copy is made of each even octupole, which copies are located in such a manner that they have the same z position as the associated even octupoles, and each of which copies is rotated through 22.5° about the z-axis w.r.t. the original associated octupole; these rotated copies now form four uneven octupoles. 2) Next, one considers each of these four rotated copies as being divided into two equal portions by a cross-section perpendicular to the z-axis, namely a first portion and a second portion, after which 3) The excitations of the first and the second portion of the uneven octupole are chosen to have such a ratio that the contribution of the uneven octupoles to the third-order axial aberrations is equal to zero, and 4) The total excitation of all uneven octupoles is chosen in such a manner that the anisotropic coma of the combination of the corrector and the objective is equal to zero. In the case of this last point 4), it should be pointed out that, as a result of the symmetry w.r.t. the mirror plane z=0, the excitation of the uneven portions is anti-symmetric w.r.t. the symmetry plane. FIGS. 3a and 3b depict the distribution of the magnetostatic field that thus arises on the z-axis. FIG. 3b represents the same field distribution as that in FIG. 3a, whereby the vertical scale of FIG. 3b is stretched by a factor of the order of magnitude of 40 w.r.t. that of FIG. 3a; as a result of this, the details of the field distribution in the vicinity of z=−45 mm to z=−100 mm and of z=+45 mm to z=+100 mm are more clearly visible. FIG. 3a depicts in more detail the field distributions on the z-axis of the octupoles O3a and O3b; in addition, the axial field of the octupoles O1 and O2 is schematically depicted therein. The axial field of the even portion of octupole O3a (O3b) is depicted herein by the solid line 40 (42), and the axial field of the uneven portion of octupole O3a (O3b) is depicted herein by a dashed line. It should be pointed out that the even and the uneven portions of O3a and O3b in the z-direction are equally long. The uneven portions are divided into two equally long portions 44 (48) and 46 (50) in the z-direction. The excitations of the uneven portions, i.e. the field strengths on the z-axis, are now chosen in such a manner that both of the abovementioned conditions are satisfied, i.e. 1) that the ratios of the field strengths 44 (48) and 46 (50) are such that the contribution of the uneven octupoles 44, 46 and 48, 50 to the third-order axial aberrations is equal to zero, and 2) that the total field strengths of the uneven octupoles 44, 46 and 48, 50, together with the uneven portions 56, 58 and 60, 62 of the octupoles O1 and O2 (see FIG. 3)—which uneven portions will be discussed later—are such that the anisotropic coma of the combination of the corrector and the objective is equal to zero. Moreover, FIG. 3b depicts in more detail the field distributions on the z-axis of the octupoles O1 and O2. The axial field of the uneven portion of octupole O1 (O2) is depicted herein by the solid line 52 (54), and the axial field of the uneven portion of octupole O1 (O2) is depicted herein by a dashed line. It should be pointed out that the even and the uneven portions of O1 and O2 in the z-direction are equally long. The uneven portions are divided into two equally long portions 56 (60) and 58 (62) in the z-direction. The excitations of the uneven portions, i.e. the field strengths on the z-axis, are now chosen in such a manner that both of the abovementioned conditions are satisfied, i.e. 1) that the ratios of the field strengths 56 (60) and 58 (62) are such that the contribution of the uneven octupoles 56, 58 and 60, 62 to the third-order axial aberrations is equal to zero, and 2) that the total field strengths of the uneven octupoles 56, 58 and 60, 62, together with the uneven portions of the octupoles O3a and O3b, are such that the anisotropic coma of the combination of the corrector and the objective is equal to zero. For a system corrected for the anisotropic coma in this manner, the aberrations of the combination of the corrector and the objective lens are indicated in the following Table 2. The values and data already set forth with regard to the description of FIG. 2a are applicable in this case. In Table 2, the aberrations in rows 1 to 5 are indicated using the symbols according to the abovementioned article by Haider et al. The letter i in Table 2 indicates the imaginary unit. #1C3, S3, A3 (mm)02C5 (mm)−0.323S5 (mm)0.11 i4D5 (mm)05A5 (mm)0.32 i6S80 (mm)57S62 (mm)−98S44 (mm)−309S26 (mm)3510S08 (mm)−511Sx30 = Sx12012Sy21 = Sy03013i Fan014Sx50815Sx32−4116Sx14317Sy41−818Sy234219Sy05−320|Sx41|, . . . |Sy50|≦521Ccx, Ccy (mm)022Cccx (mm)723Cccy (mm)1724Ccmx−3.025Ccmy3.026C3c (mm)1327S3c (mm)−1.9-0.5 i28A3c (mm)4.9In Table 2 above, row 13 is of particular importance, from which it transpires that the anisotropic coma has indeed been made exactly equal to zero. Compare herewith the corresponding value in row 13 of Table 1, in which no correction was made for the anisotropic coma.It is true that the aberration coefficients S5 and A5 indicated in rows 3 and 5 are no longer equal to zero in this embodiment, but their value is still so small as to be negligible. FIG. 4 relates to the course of rays in a corrector according to the invention for use in a SEM or a low-voltage TEM. In this figure, the course of axial rays 2 and 6 and of field rays 4 and 8 is depicted in the x-z plane and the y-z plane of the corrector. The design of the corrector used hereby was obtained according to the above-mentioned paragraph “The steps in the design process for TEM, STEM and SEM”, whereby the passages for SEM and low-voltage TEM are of particular importance. In this FIG. 4, the locations on the optical axis (the z-axis) of the six quadrupoles Q1 to Q6 are depicted, as are the locations on the z-axis of both octupoles O1 and O2, and the locations of the portions O3a and O3b of the third octupole that has been divided into two equal portions. Moreover, using the reference numerals 28, 30, 32, 34, 36 and 38, the excitation of the quadrupoles Q1, Q2, Q3, Q4, Q5 and Q6 is indicated in the form of the strength of the field on the optical axis. The plane of mirror symmetry is located at position z=0. The following values and data pertain to this design: All quadrupoles are embodied to be electromagnetic. The quadrupoles Q1 and Q6 are of themselves exactly achromatic. The quadrupoles Q2 and Q5 deviate so little from the exact achromatic state that the condition Ccmx=Ccmy=0 is satisfied. The quadrupoles Q3 and Q4 are (negatively) chromatic in such a manner that, as a result, the (positive) chromatic aberration of the objective is corrected. At the locations of the quadrupoles Q1, Q2, Q5 and Q6, magnetic octupoles of relatively low optical power have been added; these octupoles correct inter alia the intrinsic third-order aberrations of the associated quadrupoles. The portions O3a and O3b of the third octupole that has been divided into two equal portions are imaged onto the coma-free plane of the objective lens using a transfer lens system. The acceleration voltage of the electrons is 10 kV. The focal length of the objective lens to be corrected is 1.49 mm. Cc of the objective lens: 1.17 mm. Cs of the objective lens: 1.64 mm. Internal radius of the multipoles: 3 mm. Length of the quadrupoles Q3 and Q4: 17 mm. Length of the octupole portions O3a and O3b: 8 mm. Magnification of the transfer lens system: 0.764 (as a result of which the beam diameter at the entrance to the objective is 0.764 times as large as in the exit plane of the corrector).The aberrations of the combination of the corrector and the objective lens are indicated in the following table 3. In the situation set forth, the quadrupole lens in the transfer lens system (QFL) is turned off. #1C3, S3, A3 (mm)02C5 (mm)−0.473S5 (mm)04D5 (mm)05A5 (mm)06S80 (mm)287S62 (mm)−708S44 (mm)−2109S26 (mm)−4210S08 (mm)1411Sx30 = Sx12012Sy21 = Sy03013Sx503014Sx32−7715Sx14−7216Sy41−7517Sy23−2818Sy051319Ccx, Ccy (mm)020Cccx (mm)−2.221Cccy (mm)−2.222Ccmx023Ccmy024C3c (mm)025S3c (mm)026A3c (mm)0 In Table 3 above, the aberrations in rows 1 to 5 are indicated using the symbols according to the abovementioned article by M. Haider et al. In rows 6 to 10, the seventh-order aberration coefficients are indicated; as transpires from the values concerned, these are of the order of magnitude of a few centimeters at most. Rows 11 and 12 indicate the coefficients of the isotropic coma. Rows 13 to 18 indicate the coefficients of the fifth-order coma; from the values concerned, it is evident that this group of lens errors is negligible. In row 19, it transpires that the coefficients of the chromatic aberration in both the x-z plane (Ccx) and the y-z plane (Ccy) have become exactly equal to zero. In rows 20 and 21, it transpires that the coefficients of the axial chromatic error of degree two Ccc in the x-z plane (Cccx) and the y-z plane (Cccy), respectively, have been made very small. In rows 23 to 26, it transpires that the coefficients of the chromatic magnification error (Ccm) in the x-z plane (Ccmx) and the y-z plane (Ccmy), respectively, and the mixed aberrations A3c, C3c and S3c of the third order and the first degree, have been made equal to zero. FIG. 5a renders a schematic depiction of the positioning of the corrector according to the invention in a TEM. The beam of electrons thereby successively traverses a condenser system 10, a sample 12 to be investigated in the TEM, an objective lens 14, a transfer lens system 16 consisting of two transfer lenses 18 and 20, an aberration corrector 22 according to the invention, a further lens 24, and a projector system 26. The aberration corrector 22 is bordered by two portions O3a and O3b of the third octupole. FIG. 5b renders a schematic depiction of the positioning of the corrector according to the invention in a SEM or a STEM. The beam of electrons thereby successively traverses a condenser system 10, an intermediate lens 28, an aberration corrector 22 according to the invention, a transfer lens system 16 consisting of two transfer lenses 18 and 20, a probe-forming objective lens 14, and a sample 12 to be investigated in the SEM or the STEM. The aberration corrector 22 is bordered by two portions O3a and O3b of the third octupole. |
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045171548 | summary | FIELD OF THE INVENTION The present invention relates to nuclear power plants and, more particularly, to a self-test subsystem for a nuclear reactor protection system. Specifically, between sensors such as core overheat sensors and a corresponding safety or operation function, such as the insertion of rods to shutdown a reactor, there is located an electronic nuclear reactor protection system. The readiness of this system to respond to emergency conditions is the subject of this disclosure. Specifically, provision is herein disclosed for constant self-test of such systems to assure that at all times a power plant is in readiness to respond to emergency. BACKGROUND OF THE INVENTION Modern nuclear safety requirements are high. In the prior art it is known to have nuclear reactor protection systems. An example of such a system is helpful to the reader. Specifically, if core overheat is detected, it is usually detected in sensors. The sensors in turn have to communicate through a nuclear reactor protection system to actuate core apparatus for correcting the condition. Assuming that overheat has been detected by a sensor, an appropriate response (used in this disclosure as a primary example) may be the insertion of rods to absorb neutrons and shutdown the reactor. This may be part of a system wide emergency shutdown known as a "scram". In such a system there is always the danger of latent failures. Specifically, and as time lapses after a test has occurred, the probability increases that the system may be inoperative. The system must await the next actual test until proper operation can again be confirmed and a lower probability of failure established. The seriousness of undetected failures becomes even more apparent when one considers the case of so called "common mode failures". "Common mode failures" are system wide. Because they are system wide, common mode failures affect the system throughout, even at points of system redundancy. Failures due to high voltage transients, fire, earthquake, and other mechanical causes may remain latent until the system is exercised. If system exercise is to occur in response to an emergency, no one may be aware that the system is incapable of responding to the emergency until the required emergency procedure is instituted. Then it is too late. An operator may respond to an emergency in a number of different ways by moving the plant from the perilled operating state to one that is safer. All of these safer states require different operating configurations of the plant. In nuclear plants, the availability of different operating configurations has not heretofore been capable of test without actual plant manipulation. SUMMARY OF THE PRIOR ART Prior art testing of nuclear plants has included manual tests. In such manual tests, portions of the system are first isolated. Thereafter, these isolated portions are individually exercised. During such individual exercise, at least three conditions can occur, all of which are detrimental to the plant operating state. First, an isolated portion of the plant may have to be rendered inoperative for the test to occur. Whenever any portions of the plant are rendered inoperative, emergency responses and/or plant operations must of necessity be adversely affected. For example, individual exercise of rods in the reactor core will of itself affect core reaction. Secondly, while the exercise is occurring, system failure is still possible and may become even more catastrophic. Typically, the isolated portion of the system is not capable of responding to an emergency. For example, assuming that one of four banks of reactor rods is being tested and therefore rendered inoperative, failure of a second bank of reactor rods leaves shutdown capacity at a reduced level of design system capacity. Finally, some shutdown components of the system require that the system go completely off-line. When the system goes completely off-line, at best, valuable power output is lost. System losses at rates of $200,000 per hour necessitated because of tests are common and known. Moreover, testing itself can cause an undetected failure. For example, rods are actuated and a solenoid breaks while returning the rods. The result of the test shows the solenoid to be working while in actuality it is now broken and the break will not be detected until the next test. SUMMARY OF THE INVENTION A self-test system for a nuclear power plant, nuclear reactor protection system is disclosed. Nuclear protection systems are the electronic controls, typically including circuit cards, located intermediate between sensors (as for detecting core overheat) and a control (as for providing rod injection to shut down a reactor). Constant surveillance of the nuclear system protection system is provided by a microprocessor that serially addresses protection system circuit cards and loads them at predetermined input points with test commands. The addressed cards are thereafter simultaneously activated by a system-wide command. The test command is a pulse which is so short in duration that its affect is transparent to the system and cannot cause overall system operation. The pulse passes through the actuating electrical components to verify, on the real actuating path, the operating integrity of the system. After an appropriate response interval, the output state of the system is recorded in system-wide resident registers. Thereafter, with response data contained in these registers frozen at the recorded state, the output is read. This result is compared with the expected output in computer memory. If correspondence between memory output and register output is found, the next sequential set of test commands is acted upon. If correspondence is not found, a subroutine search is automatically conducted to locate the error. The disclosed self-test subsystem is duplicated in four separate divisions with each division testing one of the four duplicate protection systems. The three remaining and idle divisions constantly monitor the active subsystem's operation. The end result is an overall system which reduces the mean time to discover error, thus minimizing mean time to repair and maximizing protection system availability and safety. The separation of the protection system into four duplicate divisions is not dependent on the disclosed invention and the invention may be applied to protective systems with a different number of divisions. OTHER OBJECTS, FEATURES AND ADVANTAGES An objective of this invention is to disclose a process for testing the electronic controls of a nuclear reactor protection system. According to this aspect of the invention, test input registers throughout the nuclear reactor protection system are serially loaded on command from a computer. These test input registers, once wholly loaded, are simultaneously activated by a system-wide command. Test pulses are released, which test pulses have such short duration in real time that they are not seen by or are "transparent" to the nuclear plant operating system. The test pulses pass through the real actuating electronic components of the nuclear system thus causing the components to be in fact tested for their actual electronic integrity. Thereafter and when an appropriate period of time has passed, the response data contained in the registers are frozen so as to record the protection system's state. Once the data is frozen, the system wide registers are serially read and their output compared with predetermined, correct responses stored in memory. Where matching occurs, system integrity is verified. An advantage to this apparatus is that no part of the power plant need be isolated for testing of nuclear system integrity to occur. Therefore, even though the disclosed process is continually verifying the operational integrity of the plant, in no way is the plant's ability to respond to an emergency adversely affected. For example, in testing the controls to exercise rods in a reactor, no actual exercise of the rods is required. A further advantage of the disclosed process is that since system exercise is not required for testing, the system is at all times capable of responding to an emergency. The necessity of rendering inoperative banks of rods, for example, is not required for a test of the nuclear reactor protection system. Yet a further advantage of this apparatus is to reduce substantially the necessity of taking the system off-line. Accordingly, expensive test periods wherein system downtime is required are avoided. Yet another object of this invention is to disclose an apparatus for practicing the disclosed process. Specifically, at least one computer (here having a central processing unit and associated memories) sequentially tests various discrete systems. In the test of each group of protection system circuits, input registers at preselected locations throughout the protection system's electronic cabinets are serially addressed and thereafter loaded with test commands. When the input registers are loaded, test impulses of a duration short enough to be transparent to overall operation are simultaneously released by a system-wide pulse. This simultaneous release causes the effectively transparent pulses to travel through the real actuating path of the system. After an appropriate interval, and upon receipt of signal, the system response state is frozen in resident registers. These registers are thereafter read and their output compared to data stored in memory output to verify integrity of the real operating path of the system. An advantage of this aspect of the invention is that the test process of this invention may be continually and repeatedly practiced by a computer. The computer in practicing the test process continually and remotely verifies the operational integrity of a nuclear reactor protection system. Yet another advantage of this aspect of the invention is that the system is capable of detecting whether any discrete emergency function, in whole or in part, is sufficiently functional to move the plant to another operating state. For example, during either normal operation or crisis, an operator can ascertain relatively quickly before rearrangement of the operating state of the plant, whether the next and intended operating state of the plant is available. Yet another object of this invention is to disclose partitioning of the protection system's circuits into subgroupings in the event that an error is located. According to this aspect of the invention and where the memory output does not compare with the desired register output, partitioning of the test can occur. In such partitioning, either additional system output registers may be read or, alternatively, new system subtests may be initiated. Further, appropriate branching can be accomplished so that testing is directed with increasing particularity towards points of system failure. Yet another object of this invention is to disclose the components of the test system and in particular to disclose replacable circuit cards. According to this aspect of the invention, the cards include electronic apparatus for recognizing serial addresses and registers for input or output of either test commands or system status. These discrete cards are replacable and inventoried so that when a point of failure is located with particularity, a technician may be dispatched for card removal and replacement to restore system integrity. A further advantage of this apparatus is continuous testing wherein the mean time to discover failure is dramatically reduced. The sooner the failure is discovered and located, the sooner it can be repaired and the system be made available. Using the formula: EQU (MTBF/MTBF+MTBR=A, where: A=Availability, PA1 MTBF=Mean Time between Failures, and PA1 MTBR=Mean Time between Repairs, it is easily seen that as MTBR is reduced, availability approaches the desired 100%. An advantage of testing without affecting functional operation is that the particular system being tested remains fully operative, thus retaining full safety protection for the plant. Furthermore, when simple hardware design precautions are observed, failures in the self-test system itself cannot affect any essential circuitry of the nuclear reactor protection system. Another advantage of automatic, computerized testing over manual testing is speed. The self-test system performs a complete agenda of tests within 30 minutes as compared to many days of manual test. It also allows for testing by request as well as automatic surveillance. A further advantage of the self-test system is the ability to test using simulated plant state input to the nuclear system protection system. By not requiring the plant to be in any particular actual state to conduct the test, time is saved and availability thereby enhanced. This is especially true for seldom-used states such as core overheating which would require a scram. Yet another advantage of this invention is that there are four independent self-test controllers, one for each of the redundant nuclear system protection systems. There are no electrical connections between the four self-test controllers, the only intercommunication being through optically coupled isolators. The advantage of this isolation is that if, for example, one of the self-test controllers were shorted out it would not affect the operation of the others. Furthermore, there are minor variations in the design of the four self-test controllers (for example, wiring) in order to avoid any possible common-mode systematic design error. |
claims | 1. An installation method of equipment, comprising:forming a pit container unit including a first frame, reinforcing steel members, a pit container, and an anchor member supporting mechanism, the forming including:disposing the first frame at a location different from an installation location of the equipment;disposing the reinforcing steel members proximate to the first frame to reinforce the first frame;placing the pit container on the first frame inside the reinforcing steel members;attaching an anchor member supporting mechanism to the pit container, the anchor member supporting mechanism including a supporting member to support a ring state anchor member positioned at an outer peripheral side of the pit container and a ring state reinforcing member having a center hole wherein a part of each reinforcing steel member is passed through a gap formed between the center hole and an outer peripheral portion of the pit container;placing a second frame on a base to be the installation location of the equipment;placing pit container unit on the second frame via the first frame;embedding a portion of the pit container unit and second frame not including the anchor member supporting mechanism, in concrete using a by primary concrete pour;disposing an anchor bolt unit including a plurality of foundation bolts for equipment installation fixed to the ring state anchor member, on the anchor member supporting mechanism after embedding the portion of the pit container unit by the primary concrete pour;correcting a positional relationship of the plurality of foundation bolts relative to the pit container by using a template member having a plurality of positioning holes into which the plurality of foundation bolts on the anchor bolt unit are individually inserted;embedding the pit container unit and the anchor bolt unit in concrete using a secondary concrete pour;wherein the secondary concrete pour does not embed the template member in concrete, andwherein the positional relationship of an opening portion of the pit container and the plurality of foundation bolts is maintained by the template after the secondary concrete pour,removing the template;moving the equipment into the pit container after removal of the template member; andfixing the equipment via the plurality of foundation bolts. 2. The installation method of equipment according to claim 1, wherein correcting the positional relationship of the pit container and the plurality of foundation bolts includes:spot welding the supporting member to the anchor member after the position of the foundation bolts has been corrected to fall within a tolerance range by inserting the foundation bolts into the positioning holes of the template member. 3. The installation method of equipment according to claim 1, wherein the equipment is a vertical pump. 4. The installation method of equipment according to claim 2, wherein correcting the positional relationship of the pit container and the plurality of foundation bolts includes:removing the template member and disposing additional reinforcing steel members to reinforce an upper side of the pit container unit after the supporting member and the anchor member are spot welded. |
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