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	claims	1. An apparatus for watertight sealing of a steam generator nozzle, comprising:an attachment ring adapted to be fitted in an interior of said nozzle, said attachment ring comprising:a plurality of retaining tabs extending from an interior of said attachment ring towards a center of said attachment ring;a plurality of receiving slots formed between said retaining tabs; anda nozzle dam landing formed in the interior of the attachment ring below the retaining tabs;a nozzle dam adapted for insertion into said attachment ring and abutment against said nozzle dam landing, said nozzle dam comprising:two top disc segments;a plurality of radial protrusions extending from the two top disc segments of the nozzle dam and fixed with respect to the two top disc segments, said radial protrusions adapted to pass through said receiving slots of said attachment ring and directly interlock between and directly abut against said nozzle dam landing and said retaining tabs for fixing said nozzle dam in said attachment ring upon rotation of the nozzle dam in the attachment ring; anda seal covering at least a bottom side of the nozzle dam for effecting a watertight seal between the nozzle dam and the attachment ring. 2. An apparatus in accordance with claim 1, wherein the nozzle dam and seal form a nozzle dam assembly. 3. An apparatus in accordance with claim 2, wherein:the seal forms a hinge connecting the two top disc segments, enabling the nozzle dam. 4. An apparatus in accordance with claim 3, further comprising:a center locking mechanism for locking the two top disc segments together in an unfolded state of the nozzle dam. 5. An apparatus in accordance with claim 1, further comprising:a rotation limiting mechanism provided on the nozzle dam to prevent over-rotation of the nozzle dam in the attachment ring. 6. An apparatus in accordance with claim 1, further comprising:a locking mechanism for locking the nozzle dam into the attachment ring. 7. An apparatus in accordance with claim 6, wherein the locking mechanism comprises a locking pin or a locking tab. 8. An apparatus in accordance with claim 1, further comprising:cladding fitted into the interior of said nozzle;wherein said attachment ring is fixed in said cladding. 9. An apparatus in accordance with claim 1, wherein:the attachment ring is machined from cladding provided in the interior of the nozzle. 10. An apparatus in accordance with claim 1, wherein the seal extends over the bottom side of the nozzle dam at over at least a portion of the nozzle dam edge. 11. An apparatus in accordance with claim 1, wherein the seal extends over the bottom side of the nozzle dam and beyond the edges of the nozzle dam. 12. An apparatus in accordance with claim 1, wherein the seal comprises an inflatable seal. 13. An apparatus in accordance with claim 12, wherein the seal is pressurized remotely after interlocking of said nozzle dam in said attachment ring. 14. An apparatus in accordance with claim 13, further comprising:a computerized pressurization control and monitoring station for controlling and monitoring said remote pressurization of said seal. 15. An apparatus in accordance with claim 13, wherein said seal comprises a segmented seal having a diaphragm extending over the bottom side of the nozzle dam and pneumatic seals extending around a circumference of the nozzle dam. 16. An apparatus in accordance with claim 15, wherein two pneumatic seals are provided with an annulus arranged therebetween. 17. An apparatus in accordance with claim 15, wherein said segments of said seal are adapted to be pressurized and monitored independently by a pressurization control and monitoring station. 18. An apparatus in accordance with claim 15, wherein the diaphragm comprises a mechanical seal which is activated by flow of water.
	abstract	A method is disclosed for adjusting a collimator of an X-ray source. In an embodiment, the method includes detecting an arrangement of an X-ray detector with respect to the X-ray source; automatically determining an adjustment for the collimator based on the detected position of the X-ray detector with respect to the X-ray source; and automatically adjusting the collimator based on the determined adjustment for the collimator. An X-ray device and computer readable medium are also disclosed.
	description	The present application is a divisional of U.S. patent application Ser. No. 11/851,352, filed Sep. 6, 2007 now U.S. Pat. No. 8,135,107, which claims priority to U.S. Provisional Patent Application No. 60/842,868, filed Sep. 6, 2006, the entireties of which are hereby incorporated by reference. The present invention relates generally to the field of storing and/or transporting high level waste, such as spent nuclear fuel rods, and specifically to apparatus and methods of storing and/or transporting spent nuclear fuel rods in a dry and hermetically sealed state. In the operation of nuclear reactors, hollow zircaloy tubes filled with enriched uranium, known as fuel assemblies, are burned up inside the nuclear reactor core. It is necessary to, remove these fuel-assemblies from the reactor after their energy has been depleted to a predetermined level. Upon depletion and subsequent removal from the reactor, these spent nuclear fuel (“SNF”) rods are still highly radioactive and produce considerable heat, requiring-that great care be taken in their subsequent packaging, transporting, and storing. Specifically, the SNF emits extremely dangerous neutrons and gamma photons. It is imperative that these neutrons and gamma photons be contained at all times subsequent to removal from the reactor core. In defueling a nuclear reactor, the SNF is removed from the reactor and placed under water, in what is generally known as a spent fuel pool or pond storage. The pool water facilitates cooling of the SNF and provides adequate radiation shielding. The SNF is stored in the pool for a period of time that allows the heat and radiation to decay to a sufficiently low level so that the SNF can be transported with safety. However, because of safety, space, and economic concerns, use of the pool alone is not satisfactory where the SNF needs to be stored for any considerable length of time. Thus, when long-term storage of SNF is required, it is standard practice in the nuclear industry to store the SNF in a dry state subsequent to a brief storage period in the spent fuel pool. Dry storage of SNF typically comprises storing the SNF in a dry inert gas atmosphere encased within a structure that provides adequate radiation shielding. Systems that are used to store SNF for long periods of time in the dry state typically utilize a hermetically scalable and transportable canister or similar structure that serves as a vessel for the transfer and storage of the SNF. One such canister, known as a multi-purpose canister (“MPC”), is described in U.S. Pat. No. 5,898,747, to Krishna P. Singh, issued Apr. 27, 1999, the entirety of which is hereby incorporated by reference. Typically, the SNF is loaded into an open canister that is submerged under water in a fuel pool. Once loaded with SNF, the canister is removed from the pool, placed in a staging area, dewatered, dried, hermetically sealed and transported to a storage facility. An example of a canister drying method can be found in U.S. Pat. No. 7,096,600, to Krishna P. Singh, issued Aug. 29, 2006, the entirety of which is hereby incorporated by reference. Because a typical canister does not by itself provide the necessary radiation shielding properties, canisters are often positioned within large storage containers known as casks/overpacks during all stages of transportation and/or storage. An example of a canister transfer and storage operation can be found in U.S. Pat. No. 6,625,246, to Krishna P. Singh, issued Sep. 23, 2003, the entirety of which is hereby incorporated by reference. A dry storage canister (“DSC”) provides the confinement boundary for the stored SNF. Thus, the structural and hermetic integrity of the DSC is extremely important. An existing DSC is sold in the United States by Transnuclear, Inc. of Columbia, Md. under the tradename NUHOMS. The NUHOMS DSC is a single-walled vessel with two top closure lids, including an inner top lid and an outer top lid. The closure lids are welded to a canister body after the SNF has been loaded into it. In the United States, the practice of using two closure lids to create a double confinement barrier only at the field welded closure location is motivated by the fact that field welds are generally less sound than those made in the factory. However, in other countries, the creation of a double confinement barrier only at the field welded closure does not meet nuclear regulatory mandates. For example, Ukrainian regulatory practice calls for a double confinement boundary all around the SNF. To meet this dual-confinement requirement, the NUHOMS DSC comprises a hermetically-sealed fuel tube in which SNF rods in the form of a fuel bundle (half of a fuel assembly) is placed. These fuel tubes are positioned within the main cavity of the NUHOMS DSC. However, the body of the NUHOMS DSC remains a single-walled cylindrical vessel. The fuel tube concept of the NUHOMS DSC meets the basic Ukrainian regulation that a double confinement boundary exist all around the SNF. However, as will be discussed in greater detail below, it has been discovered that this design suffers from a number of significant drawbacks and engineering design flaws. It is an object of the present invention to provide an apparatus for transporting, storing and/or supporting high level radioactive waste. It is another object of the present invention to provide an apparatus for transporting, storing and/or supporting spent nuclear fuel. A further object of the present invention is to provide an apparatus for storing spent nuclear fuel that essentially precludes the potential of radiological release to the environment. A yet further object of the present invention is to provide an apparatus for storing, transporting and/or supporting spent nuclear fuel in a dry state. Another object of the present invention is to create a system of storing spent nuclear fuel with two independent containment boundaries around the entirety of the spent nuclear fuel stored therein that contain radiological matter, such as gases and/or particulates. A further object of the present invention is to provide an apparatus for storing spent nuclear fuel with two independent radiological containment boundaries that facilitate heat removal via conformal contact therebetween. A still further object of the present invention is to provide a canister for storing spent nuclear fuel having two independent radiological containment boundaries surrounding a cavity. Another object of the present invention is to provide an improved fuel basket for supporting spent nuclear fuel. A still further object of the present invention is to provide a vented fuel tube for holding high level radioactive waste. Yet another object is to provide a fuel basket that can efficiently accommodate both poison rods and spent nuclear fuel. These and other objects are met by the present invention, which one aspect can be a canister for storing and/or transporting spent nuclear fuel rods comprising: a first shell forming a cavity for receiving spent nuclear fuel rods; a first plate connected to the first shell so as to form a floor of the cavity; a first lid enclosing the cavity; the first shell, the first plate and the first lid forming a first hermetic containment boundary about the cavity; a basket for supporting a plurality of spent nuclear fuel rods positioned within the cavity; a second shell surrounding the first shell so that an inner surface of the second shell is in substantially continuous surface contact with an outer surface of the first shell; a second plate connected to the second shell; a second lid; and the second shell, the second plate and the second lid forming a second hermetic containment boundary that surrounds the first radiation containment boundary. In another aspect, the invention can be a canister apparatus for storing and/or transporting spent nuclear fuel rods comprising: a first pressure vessel comprising a first shell forming a first cavity for receiving spent nuclear fuel rods, a first plate connected to the first shell so as to enclose a first end of the first cavity, and a first lid connected to the first shell so as to enclose a second end of the first cavity; a second pressure vessel comprising a second shell forming a second cavity, a second plate connected to the second shell so as to enclose a first end of the second cavity, and a second lid connected to the second shell so as to enclose a second end of the second cavity; and the first pressure vessel located within the second cavity so that an inner surface of the second shell is in substantially continuous surface contact with an outer surface of the first shell. In yet another aspect, the invention can be a canister apparatus for storing transporting spent nuclear fuel rods comprising: a first metal pressure vessel having an outer surface and forming a cavity for receiving spent nuclear fuel rods; a second metal pressure vessel having an inner surface; and the first pressure vessel located within the second pressure vessel so that a substantial entirety of the outer surface of the first metal pressure vessel is in substantially continuous surface contact with the inner surface of the second metal pressure vessel. In still another aspect, the invention can be a canister apparatus for storing and/or transporting spent nuclear fuel rods comprising: a first structural assembly forming a cavity for receiving spent nuclear fuel rods, the first structural assembly forming a first gas-tight containment boundary surrounding the cavity; a second structural assembly surrounding the first structural assembly, the second structural assembly forming a second gas-tight containment boundary surrounding the cavity; and wherein the first structural assembly and second structural assembly are in substantially continuous surface contact with one another. In yet another aspect, the invention can be a basket apparatus for supporting a plurality of spent nuclear fuel rods within a containment structure comprising: a plurality of disk-like grates, each disk-like grate having a plurality of cells formed by a gridwork of beams; and means for supporting the disk-like grates in a spaced arrangement with respect to one another and so that the cells of the disk-like grates are aligned. In a further aspect, the invention can be a basket apparatus for supporting a plurality of spent nuclear fuel rods within a containment structure comprising: a disk-like grate having a ring-like structure encompassing a gridwork of beams; the gridwork of beams comprising a first series of parallel beams, a second series of parallel beams and a third series of parallel beams; and wherein the first, second and third series of parallel beams are arranged in the ring-like structures so as to intersect and form a plurality of cells. In another aspect, the invention can be a basket apparatus for supporting a plurality of spent nuclear fuel rods within a containment structure comprising: a disk-like grate having a ring-like structure encompassing a gridwork of beams; and the gridwork of beams forming a first set of cells having a first shape and a second set of cells having a second shape. Referring to FIG. 1, a dual-walled DSC 100 according to one embodiment of the present invention is disclosed. The dual-walled DSC 100 and its components are illustrated and described as an MPC style structure. However, it is to be understood that the concepts and ideas disclosed herein can be applied to other areas of high level radioactive waste storage, transportation and support. Moreover, while the dual-walled DSC 100 is described as being used in combination with a specially designed fuel basket 90 (which in of itself constitutes an invention), the dual-walled DSC 100 can be used with any style of fuel basket, such as the one described in U.S. Pat. No. 5,898,747, to Krishna P. Singh, issued Apr. 27, 1999. In fact, in some instances it may be possible to use the dual-walled DSC 100 without a fuel basket, depending on the intended function. Furthermore; the dual-walled DSC 100 can be used to store and/or transport any type of high level radioactive waste and is not limited to SNF. As will become apparent from the structural description below, the dual-walled DSC 100 contains two independent containment boundaries about the storage cavity 30 that operate to contain both fluidic (gas and liquid) and particulate radiological matter within the cavity 30. As a result, if one containment boundary were to fail, the other containment boundary will remain intact. While theoretically the same, the containment boundaries formed by the dual-walled DSC 100 about the cavity 30 can be literalized in many ways, including without limitation a gas-tight containment boundary, a pressure vessel, a hermetic containment boundary, a radiological containment boundary, and a containment boundary for fluidic and particulate matter. These terms are used synonymously throughout this application. In one instance, these terms generally refer to a type of boundary that surrounds a space and prohibits all fluidic and particulate matter from escaping from and/or entering into the space when subjected to the required operating conditions, such as pressures, temperatures, etc. Finally, while the dual-walled DSC 100 is illustrated and described in a vertical orientation, it is to be understood that the dual-walled DSC 100 can be used to store and/or transport its load in any desired orientation, including at an angle or horizontally. Thus, use of all relative terms through this specification, including without limitation “top,” “bottom,” “inner” and “outer,” are used for convenience only and are not intended to be limiting of the invention in such a manner. The dual-walled DSC 100 dispenses with the single-walled body concept of the prior art DSCs. More specifically, the dual walled DSC 100 comprises a first shell that acts as an inner shell 10 and a second shell that acts as an outer shell 20. The inner and outer shells 10, 20 are preferably cylindrical tubes and are constructed of a metal. Of course, other shapes can be used if desired. The inner shell 10 is a tubular hollow shell that comprises an inner surface 11, an outer surface 12, a top edge 13 and a bottom edge 14. The inner surface 11 of the inner shell 10 forms a cavity/space 30 for receiving and storing SNF. The cavity 30 is a cylindrical cavity formed about a central axis. The outer shell 20 is also a tubular hollow shell that comprises an inner surface 21, an outer surface 22, a top edge 23 and a bottom edge 24. The outer shell 20 circumferentially surrounds the inner shell 10. The inner shell 10 and the outer shell 20 are constructed so that the inner surface 21 of the outer shell 20 is in substantially continuous surface contact with the outer surface 12 of the inner shell 10. In other words, the interface between the inner shell 10 and the outer shell 20 is substantially free of gaps/voids and are in conformal contact. This can be achieved through an explosive joining, a cladding process, a roller bonding process and/or a mechanical compression process that bonds the inner shell 10 to the outer shell 20. The continuous surface contact at the interface between the inner shell 10 and the outer shell 20 reduces the resistance to the transmission of heat through the inner and outer shells 10, 20 to a negligible value. Thus, heat emanating from the SNF loaded within the cavity 30 can efficiently and effectively be conducted outward through the shells 10, 20 where it is removed from the outer surface 22 of the outer shell via convection. The inner and outer shells 10, 20 are preferably both made of a metal. As used herein, the term metal refers to both pure metals and metal alloys. Suitable metals include without limitation austenitic stainless steel and other alloys including Hastelloy™ and Inconel™. Of course, other materials can be utilized. The thickness of each of the inner and outer shells 10, 20 is preferably in the range of 5 mm to 25 mm. The outer diameter of the outer shell 20 is preferably in the range of 1700 mm to 2000 mm. The inner diameter of the inner shell 10 is preferably in the range of 1700 mm to 1900 mm. The invention, however, is not limited to any specific size and/or thickness of the shells 10, 20. In some embodiments, it may be further preferable that the inner shell 10 be constructed of a metal that has a coefficient of thermal expansion that is equal to or greater than the coefficient of thermal expansion of the metal of which the outer shell 20 is constructed. Thus, when the SNF that is stored in the cavity 30 and emits heat, the outer shell 20 will not expand away from the inner shell 10. This ensures that the continuous surface contact between the outer surface 12 of the inner shell 10 and the outer surface 21 of the outer shell 20 will be maintained and a gaps will not form under heat loading conditions. The dual-walled DSC 100 further comprises a first lid that acts as an inner top lid 60 for the inner shell 10 and a second lid that acts as an outer top lid 70 for the second shell 20. The inner and outer top lids 60, 70 are plate-like structures that are preferably constructed of the same materials discussed above with respect to the shells 10, 20. Preferably the thickness of the inner top lid 60 is in the range of 100 mm to 300 mm. The thickness of the outer top lid is preferably in the range of 50 mm to 150 mm. The invention is not, however, limited to any specific dimensions, which will be dictated on a case-by-case basis and the radioactive levels of the SNF to be stored in the cavity 30. Referring now to FIG. 2, the inner top lid 60 comprises a top surface 61, a bottom surface 62 and an outer lateral surface/edge 63. The outer top lid 70 comprises a top surface 71, a bottom surface 72 and an outer lateral surface/edge 73. When fully assembled, the outer lid 70 is positioned atop the inner lid 60 so that the bottom surface 72 of the outer lid 70 is in substantially continuous surface contact with the top surface 61 of the inner lid 60. During an SNF underwater loading procedure, the inner and outer lids 60, 70 are removed. Once the cavity 30 is loaded with the SNF, the inner top lid 60 is positioned so as to enclose the top end of the cavity 30 and rests atop the brackets 15. Once the inner top lid 60 is in place and seal welded to the inner shell 10, the cavity 30 is evacuated/dried via the appropriate method and backfilled with nitrogen, helium or another inert gas. The drying and backfilling process of the cavity 30 is achieved via the holes 64 of the inner lid 60 that form passageways into the cavity 30. Once the drying and backfilling is complete, the holes 61 are filled with a metal or other wise plugged so as to hermetically seal the cavity 30. Referring now to FIGS. 1 and 3 concurrently, the outer shell 20 has an axial length L2 that is greater than the axial length L1 of the inner shell 10. As such, the top edge 13 of the inner shell 10 extends beyond the top edge 23 of the outer shell 20. Similarly, the bottom edge 24 of the outer shell 20 extends beyond the bottom edge 13 of the inner shell 10. The offset between the top edges 13, 23 of the shells 10, 20 allows the top edge 13 of the inner shell 10 to act as a ledge for receiving and supporting the outer top lid 70. When the inner lid 60 is in place, the inner surface 11 of the inner shell 10 extends over the outer lateral edges 63. When the outer lid 70 is then positioned atop the inner lid 60, the inner surface 21 of the outer shell 20 extends over the outer lateral edge 73 of the outer top lid 70. The top edge 23 of the outer shell 20 is substantially flush with the top surface 71 of the outer fop lid 70. The inner and outer top lids 60, 70 are welded to the inner and outer shells 10, 20 respectively after the fuel is loaded into the cavity 30. Conventional edge groove welds can be used. However, it is preferred that all connections between the components of the dual-walled DSC 100 be through-thickness weld. The dual-walled DSC 100 further comprises a first plate that acts as an inner base plate 40 and a second plate that acts as an outer base plate 50. The inner and outer base plates 40,50 are rigid plate-like structures having circular horizontal cross-sections. The invention is not so limited, however, and the shape and size of the base plates 40, 50 is dependent upon the shape of the inner and outer shells 10, 20. The inner base plate 40 comprises a top surface 41, a bottom surface 42 and an outer lateral surface/edge 43. Similarly, the outer base plate 50 comprises a top surface 51, a bottom surface 52 and an outer lateral surface/edge 53. The top surface 41 of the inner base plate 40 forms the floor of the cavity 30. The inner base plate 40 rests atop the outer base plate 50. Similar to the other corresponding components of the dual-walled DSC 100, the bottom surface 42 of the inner base plate 40 is in substantially continuous surface contact with the top surface 51 of the outer base plate 50. As a result, the interface between the inner base plate 40 and the outer base plate 50 is free of gaseous gaps/voids for thermal conduction optimization. An explosive joining, a cladding process, a roller bonding process and/or a mechanical compression process can be used to effectuate the contact between the base plates 40, 50. Preferably, the thickness of the inner base plate 40 is in the range of 50 mm to 150 mm. The thickness of the outer base plate 50 is preferably in the range of 100 mm to 200 mm. Preferably, the length from the top surface of the outer top lid 70 to the bottom surface of the outer base plate 50 is in the range of 4000 mm to 5000 mm, but the invention is in no way limited to any specific dimensions. The outer base plate 50 may be equipped on its bottom surface with a grapple ring (not shown) for handling purposes. The thickness of the grapple ring is preferably between 50 mm and 150 mm. The outer diameter of the grapple ring is preferably between 350 mm and 450 mm. Referring now to FIGS. 2 and 4 concurrently, the inner shell 10 rests atop the inner base plate 40 in a substantially upright orientation. The bottom edge 14 of the inner shell 10 is connected to the top surface 41 of the inner base plate 40 by a through-thickness single groove (V or J shape) weld. The outer surface 12 of the inner shell 10 is substantially flush with the outer lateral edge 43 of the inner base plate 40. The outer shell 20, which circumferentially surrounds the inner shell 10, extends over the outer lateral edges 43, 53 of the inner and outer base plates 40, 50 so that the bottom edge 24 of the outer shell 20 is substantially flush with the bottom surface 52 of the outer base plate 50. The inner surface 21 of the outer shell 20 is also connected to the outer base plate 50 using a through-thickness edge weld. In an alternative embodiment, the bottom edge 24 of the outer shell 20 could rest atop the top surface 51 of the outer base plate 50 (rather than extending over the outer later edge of the base plate 50). In that embodiment, the bottom edge 24 of the outer shell 20 could be welded to the top surface 51 of the outer base plate 50. When all of the seal welds discussed above are completed, the combination of the inner shell 10, the inner base plate 40 and the inner top lid 60 forms a first hermetically sealed structure surrounding the cavity 30, thereby creating a first pressure vessel. Similarly, the combination of the outer shell 20, the outer base plate 50 and the outer top lid 70 form a second sealed structure about the first hermetically sealed structure, thereby creating a second pressure vessel about the first pressure vessel and the cavity 30. Theoretically, the first pressure vessel is located within the internal cavity of the second pressure vessel. Each pressure vessel is engineered to autonomously meet the stress limits of the ASME Code with significant margins. Unlike the prior art DSC, all of the SNF stored in the cavity 30 of the dual-walled DSC 100 share a common confinement space. The common confinement space (i.e, cavity 30) is protected by two independent gas-tight pressure retention boundaries. Each of these boundaries can withstand both sub-atmospheric supra-atmospheric pressures as needed, even when subjecte to the thermal load given off by the SNF within the cavity 30. Referring now to FIG. 5, the dual-walled DSC 100 is illustrated having a fuel basket 90 positioned within the cavity 30 in a free-standing orientation. The fuel basket 90 serves to hold and support a plurality of SNF rods (which are located within fuel tubes 91) in the desired arrangement and maintains the desired separate locality. The fuel basket 90 comprises a plurality of disk-like grates 92 arranged in a stacked and spaced orientation. The separation between the disk-like grates 92 is accomplished via a plurality of vertically oriented tie-rods that pass through the cells of the disk-like grates 92. Once the tie rods are in place, one of the disk-like grates 92 is slid into position. Tubular sleeves that can not pass through the cells are then placed over the tie-rods and above the disk-like grates 92 in place. The next disk-like grates 92 is then slid down the tie rods. However, because the tubular sleeves can not pass through the disk-like grates 92, the two disk-like grates 92 are maintained in the spaced relation. The grates 92 are disc-like frames comprising a ring 185 and a plurality of series of beams 182, 183, 184. The outer surface 186 of the ring 185 is in surface contact with the inner surface 11 of the inner shell 10. The outer diameter of the disk-like grate 92 is preferably 1700 mm to 1900 mm. The outer diameter, however, is dependent upon the size of the cavity 30. In the illustrated embodiment, the number of grates 92 is nine, and the thickness of each grate 92 is preferably between 1 mm and 10 mm. However, the invention is not so limited, so long as the SNF rods are adequately supported within the cavity 30. Referring now to FIGS. 5 and 6, concurrently, the fuel basket 90 further comprises a plurality of ventilate fuel tubes 91. As will be discussed in greater detail below, when assembled, the ventilated fuel tubes 91 are inserted through the cells 180 of the stack of grates 92, which are aligned. The ventilated fuel tubes 91 form cylindrical cavities 193 (FIG. 9) in which the SNF rods will reside. Preferably, the fuel cells 180 around the outer perimeter of the grates 92 (i.e. the slots 180 nearest to the inner surface 11 of the inner shell 10) remain free of SNF rods. Referring now to FIG. 7, the grates 92 also comprise a plurality of smaller cells 181 for slidably receiving poison rods 93. The poison rods 93 are provided between the loaded fuel tubes 91 to control reactivity in necessary cases. The number of poison rods 93 is selected to ensure that the computed keff the SNF rods at maximum design basis initial enrichment, with no credit for burn up, and with the inclusion of all uncertainties and biases is less than 0.95. However, in some embodiments, the poison rods 93 may not be required at all. The pitch P between each of the ventilated fuel tubes 91 is between 100 mm and 150 mm. The invention is not so limited however, and the pitch between the ventilated fuel tubes 91 is affected by both the size of the cavity 30 and the number and location of the poison rods 93, and the radioactivity of the load to be stored. Referring now to FIG. 8, a top view of one of the grates 92 is illustrated. The grate 92 is a honey-comb grid like structure. The grates 92 comprise a ring structure 185, a first series of substantially parallel beams 182, a second series of substantially parallel beams 183 and a third series of substantially parallel beams 184. The ring structure 185 encompasses the a first, second and third series of substantially parallel beams 182-184. The entire grate 92 can be constructed of a metal, such as steel or aluminum, or any of the materials discussed above. The first, second and third series of substantially parallel beams 182-184 are arranged within the ring structure 185 so that each one of the series of beams 182-184 intersects with the other two series of beams 182-184. The intersection of the series beams 182-184 forms a gridwork that results in an array of fuel cells 180 and an array of poison rod cells 181. More specifically, the general outline of the fuel cells 180 is created by the intersection of the first and second series of beams 182,183 while the poison rod cells 181 are created by the intersection of the third series of beams 184 with the first and second series of beams 182, 183. When assembled, the fuel cells 180 receive the fuel tubes 91 while the poison rod cells 181 receive the poison rods 93. As can be seen the poison rod cells 181 are smaller and of a different shape than the fuel cells 180. The relative arrangement of first, second and third series of substantially parallel beams 182-184 with respect to one another is specifically selected to create hexagonal shaped fuel cells 180 and triangular shaped poison cells 181. Of course, additional series of beams and/or arrangement can be used to create cells that have different shapes, including octagonal, pentagonal, circular, square, etc. The desired shape may be dictated by the shape of the fuel tube and SNF fuel assembly to be stored. The series of beams 182, 183, 184 are rectangular strips (i.e., elongated plates) having notches (not visible) strategically located along their length to facilitate assembly. More specifically, notches that extend into the edges of the beams for at least ½ the height of the beams are provided. The notches are arranged on the beams 182-184 so that when the beams 182-184 are arranged in the desired gridwork, the notches of the bottom edge of some beams 182-184 are aligned with the notches on the top edge of the remaining beams 182-184. The beams 182-184 can then slidably mate with one another via the interaction between the notches. The beams 182, 183, 184 are then welded to each other at their intersecting points via tungsten inert gas process. While the beams 182-184 are illustrated as strips, the invention is not so limited and other structures may be used to form the gridwork, such as rods. Referring now to FIG, 9, the structure of the poison rods 93 and the ventilated fuel tubes 91 will be described. In the illustrated embodiment, the poison rods 93 are hollow tubular members having a cavity 196 for receiving a neutron absorbing material. For example, the hollow tubular member can be constructed of a stainless steel and filled with boron-carbide powder. In other embodiment, the poison rods 93 can be constructed of a monolithic material, such as a metal matrix material, such as Metamic™. The outer diameter of the poison rods 93 is between 20 mm and 40 mm and the inner diameter is between 10 mm and 40 mm. The invention is not so limited, however. When assembled in the DSC 100, the poison rods 93 are of a sufficient length so as to extend along the full height of the SNF rods stored within the fuel tubes 91. Turning now to the fuel tubes 91, the ventilated fuel tubes 91 are designed to allow for ventilation of heat emitted by the SNF rods 200 stored therein. The ventilated fuel tube 91 comprises a tubular body portion 191 and a ventilated cap portion 192. The tubular body portion 191 forms a cavity 193 for receiving the SNF rods 200, e.g., in the form of fuel bundles (half fuel assemblies). Preferably, the ventilated fuel tubes 91 have a horizontal cross sectional profile such that the cavity 193 accommodates no more than one fuel bundle. However, this is not limiting of the invention. The outer and inner diameter of the tubular body portion 191 of the ventilated fuel tube 91 is preferably between 75 mm and 125 mm, but the invention is not so limited. The tubular body portion 191 comprises a closed bottom end 194 and open top end 197. The closed bottom end 197 is a tapered and flat bottom. As will be discussed in further detail below, the tapering of the closed bottom end 197 allows for better air flow through the dual walled DSC 100. In an alternative embodiment, the closed bottom end 197 could further comprise holes and/or vents for improved air flow and heat removal. The ventilated cap portion 192 is connected to the open top end of the body portion 191 once the cavity 193 is filled with the SNF rods 200. The cap portion 192 is a non-unitary structure with respect to the tubular body 191 and removable therefrom. The caps 192 prevent any of the solid contents from spilling out during handling operations in the processing facility. The caps 192 of the tubes 91 comprise one or more openings 195 that provide passageways into the cavity 193 from the cavity 30. The openings 195 are covered with fine-mesh screen (not visible) so as to prevent any build-up of pressure in the fuel tube 191 while containing any small debris within the cavity 193 of the tube 91. It has been discovered that one inherent flaw in the design of the NUHOMS DSC is that the hermetically sealed fuel tube creates a mini-pressure vessel around the SNF rods stored therein. Because of the small confinement space/volume available in the hermetically sealed fuel tube of the NUHOMS DSC, even a small amount of water or release of plenum gas from the inside of the SNF rods can raise the internal pressure in the fuel tube steeply, rendering it susceptible to bursting. As a result, the integrity of the fuel tube of the NUHOMS DSC as a pressure vessel can not be assured when used to store previously waterlogged SNF rods that contain micro-cracks with a high level of confidence. The ventilated fuel tubes 91 of the present invention, on the other hand, prevent pressure buil-up by allowing ventilation with the larger cavity 30 via the opening 195 in the cap 192 The openings 195 are generally triangular in shape, but can be circular, rectangular or any other shape, so long as the proper venting is achieved. Referring again to FIG. 5, when the ventilated fuel tubes 92 are positioned in the dual walled DSC 100, a plenum exists between the top of the ventilated fuel tubes 91 and the bottom surface 62 of the inner top lid 60. As mentioned previously, it is also preferable that the perimeter of the grid plate 92 remain free of fuel tubes 91. Whereas the present invention has been described in detail herein, it should be understood that other and further modifications, apart from those shown Or suggested herein, may be made within the spirit and scope of the present invention. It is also intended that all matter contained in the foregoing description or shown in any accompanying drawings shall be interpreted as illustrative rather than limiting.
054950627	summary	TECHNICAL FIELD The present invention relates to methods of decontaminating soil, and more specifically, to the decontamination of nuclear waste-containing soils by methods which also permit the reclamation of residual soil products. BACKGROUND OF THE INVENTION As a result of military testing programs involving the detonation of nuclear devices, both in the United States and abroad, the environment, and particularly vast areas of soil in testing zones have become contaminated with nuclear waste materials. In some instances, for example, detonation of a nuclear device failed to achieve the needed critical mass of the radioactive components, resulting in substantial quantities of enriched uranium and plutonium being scattered over wide areas of desert testing grounds. In addition to nuclear testing programs, contamination of soil with radioactive materials has occurred at nuclear weapon manufacturing sites, such as at Hanford, Wash.; Rocky Flats, Colo.; Savannah River, Ga.; Oak Ridge, Tenn., and elsewhere through spills or releases into the environment. Efforts to successfully decontaminate these sites have proven difficult and extremely costly due to massive amounts of soil requiring treatment and/or storage. Cleanup has usually meant a slow and costly process where the contaminated soil is excavated and transferred to a different location for storage. Abandoned salt mines and mountain repositories have been proposed as storage facilities for nuclear wastes, but too often rejected later on for technical and/or political reasons. Because of a finite amount of space available for storage of nuclear waste materials progress in the reclamation of contaminated sites has been slow. In an effort to mitigate the nuclear waste storage crisis systems for reducing bulk quantities of contaminated soil requiring storage have been proposed wherein the radioactive components are concentrated in a soil fraction. One system, for example, employs an aqueous washing process requiring the use of soil scrubbing chemicals, multiple separation steps, water treatment, and so on. Although quite effective in concentrating radioactive components in silt and clay fractions of soil, capital and operating costs per ton of soil treated are viewed as economically unattractive. Consequently, most methods proposed for concentrating nuclear waste have not received wide acceptance. Accordingly, there is need for an innovative, cost-effective process for decontaminating soils containing nuclear waste materials, such as those generated at sites of nuclear weapon plants, nuclear testing sites, and wherever treatment calls for managing substantial volumes of soil contaminated with radioactive materials. The process should enable reduction of the space otherwise required for storage of untreated soils by concentrating in a small fraction of the soil while also permitting reclamation of these sites. SUMMARY OF THE INVENTION It is therefore a principal object of the invention to provide improved, more economic methods for separating radioactive ,components from contaminated soil wherein the treated soil is made sufficiently free of the potentially toxic radioactive components as to permit reclamation of the soil. The expression "sufficiently free" is intended to mean soil treated according to the present invention so it (i) is practically devoid of all unwanted radioisotopes (radionuclides), or (ii) contains residual amounts of low-level radioisotopes allowing treated soil to be reclaimed as is, or (iii) contains amounts of low-level radioisotopes which can be diluted sufficiently with an inert material to reduce its activity to an acceptable level. Expressions, such as "nuclear waste" and "radioactive waste" as recited in the specification and claims are intended to refer to soils contaminated with isotopic forms of elements having unstable nuclei which disintegrate and emit energy most commonly as alpha particles, beta particles and gamma rays. They include mainly products or by-products of nuclear fission or unreacted products of a nuclear device. Representative examples include such radionuclides as Cs.sup.137 ; Co.sup.60 ; K.sup.40 ; Pu.sup.235 ; U.sup.235 ; U.sup.238 ; Ru.sup.103 ; Te.sup.99 ; Sr; Rb; Y; Re; Rh; Pd; Tc; Np and Am. Methods of the invention provide for the recovery of nuclear waste materials in soil fractions, particularly in small, high surface area particles, such as soil fines and silt fractions of clay for subsequent storage or further treatment. By concentrating nuclear waste materials in soil fines and clay silt, for example, storage space requirements per ton of soil treated are significantly reduced, perhaps by as much as 90 percent over storage space requirements otherwise required for untreated soils. Methods of the invention comprise the steps of: (a) mixing a liquid ammonia with a soil contaminated with nuclear waste in a closed vessel to form an ammonia-nuclear waste containing soil dispersion or slurry; PA1 (b) allowing soil particles to selectively precipitate from the slurry or dispersion of step (a) to form a lower solid phase of soil particulates while forming an upper liquid-solid phase comprising soil fines dispersed in the liquid ammonia. The soil particulates of the lower solid phase have a greater bulk density relative to the soil fines of the upper liquid-solid phase; PA1 (c) separating the upper liquid-solid phase from the lower solid phase of soil particulates, the fines of the upper liquid-solid phase having the majority of the radionuclide contaminant(s), or in other words, the lower solid phase is sufficiently free of the nuclear waste materials, and PA1 (d) separating the ammonia from the soil fines containing the nuclear waste material for disposal or further treatment of the fines. PA1 (a) mixing a liquid ammonia with soil contaminated with nuclear waste in a closed vessel to form an ammonia-nuclear waste-containing soil dispersion or slurry; PA1 (b) treating the dispersion or slurry of step (a) with solvated electrons by contacting with a reactive metal; PA1 (c) allowing soil particles to selectively precipitate from the dispersion or slurry of step (b) to form a lower solid phase of soil particulates while forming an upper liquid-solid phase comprising soil fines suspended in the liquid ammonia, the soil particulates of the lower solid phase having a greater bulk density relative to the soil fines of the upper liquid-solid phase; PA1 (d) separating the upper liquid-solid phase from the lower solid phase of soil particulates, the lower solid phase of soil particulates being sufficiently free of the nuclear waste, and PA1 (e) separating the ammonia from the soil fines for disposal or further treatment of the fines. The term "disposal" is intended to include storage of the nuclear waste-containing soil fines. The expression "further treatment" is intended to include any procedure which will modify the potentially toxic properties of the radionuclide material to substances of reduced toxicity and impact on the environment, or to materials which can be recovered as useful by-products. It will be understood, methods of storage and further treatment of the concentrated nuclear waste material do not constitute part of this invention. Such methods are known by persons skilled in the art. Mazur et al in U.S. Pat. No. 5,110,364 disclose ammonia as a pretreatment in desorbing organic compounds, and particularly halogenated organic compounds like PCBs from soil, followed by chemical destruction of the compound by dehalogenation through a chemical reduction mechanism with solvated electrons. Mazur et al, however, fail to teach or suggest utilizing ammonia as a means of separating soil into fractions wherein the larger, lower surface area particulates are allowed to separate out from the less dense liquid ammonia-solid phase containing the smaller, higher surface area soil fines. In contradistinction, the methods of Mazur et al provide for treating "whole" soil in the reduction of the halogenated carbon compound contaminants without first isolating particles from the slurry containing the highest concentration of the contaminant. Serendipitously, it was found that radionuclides appear to have a preferential affinity for the smaller, higher surface area fines and silts of soils, clays and sand. Hence, by isolating the fines and silt particulates, especially the smaller particles having higher surface areas relative to the particles precipitating out of ammonia-soil dispersions one, in effect, is selectively concentrating the nuclear waste material in the smallest volume of natural solid carrier material to effectively lessen the tonnage volume of material requiring storage or further treatment. Accordingly, it is a primary objective of the invention to provide an improved more economic method for concentrating a substantial portion of the nuclear waste material in a reduced soil fraction for more efficient management of soil cleanup projects involving large volumes of soil, so as to permit reclamation of major volumes of previously contaminated soil. It is still a further object of the invention to optionally include the step of recovering and recycling for reuse in the foregoing process the ammonia from step (d), the recovery and recycling being performed by methods already known in the art. For purposes of this invention, the expression "liquid ammonia" as used herein is intended to include anhydrous liquid ammonia or ammonia-containing solutions, such as aqueous ammonia solutions. It is still a further object to provide an additional embodiment of the invention for decontaminating soil containing nuclear waste by the steps of: While this inventor has observed that ammonia has a unique ability to form very fine slurries when mixed with soils, it was observed that dispersions of soil appear to be further altered by some mechanism not fully understood, when in the presence of solvated electrons formed by dissolving metal reactions with ammonia. That is, by contacting the ammoniated soil dispersion with either an alkali or alkaline earth metal, solvated electrons are formed in the mixture, in-situ. The solvated electrons appear in some instances to optimize separation of smaller soil fines. In some instances where particle size cross-section is larger than desired, electrons solvated in liquid ammonia appear to provide more optimal demarcation and separation of the smaller fines containing nuclear waste materials from other particles of the slurry. As in the first embodiment of the invention, the foregoing second embodiment of the invention contemplates the step of recovering and recycling the ammonia from step (e) for reuse. Similarly, the precipitated residual solid soil particles of step (d) are sufficiently free of radioisotopes to permit reclamation of large bulk volumes of soil.
	abstract	A computer implemented method, apparatus, and computer usable program code to collect information for a system or processor having a transition between an idle state and a non-idle state. Idle counts occurring during execution of code are collected to form collected system or processor information. The collected system or processor information is provided to an application for analyzing why a processor becomes idle.
046506306	summary	BACKGROUND OF THE INVENTION This invention relates to a process and apparatus for producing energy through the fusion of atomic nuclei and more particularly relates to a novel process and apparatus wherein the particles which are to enter into the fusion reaction are contained in counter-moving, relatively low energy beams in vacuum without a plasma. The production of energy in a fusion reaction is well known although a successful self-maintaining process has not yet been carried out. The fusion reaction for the production of energy is desirable since it employs readily available fuels, particularly isotopes of hydrogen, and since fusion energy is safe and environmentally acceptable. The process is safe because very small amounts of particles, particularly deuterium and tritium, react at any instant so that a large uncontrolled release of energy is impossible. Moreover, fusion is inherently safe since the fusion process is quenched in response to any failure of the confinement system. In order to obtain a self-sustained fusion reaction it is known that the so-called Lawson criterion must be satisfied. The Lawson criterion places inherent requirements on fusion systems such as the pulsed Tokamak system so that a power density in a plasma of deuterium and tritium must be about 18 kilowatts per cubic centimeter while a magnetic confinement field is required for the creation of the magnetic bottle which confines the plasma in a magnetic field of about 140 kilogauss. These requirements are extremely difficult to fulfill and explain the long delay in completion of, and high capital cost of Tokamak type equipment which will be capable of carrying out a self-sustained fusion process. More specifically, some of the difficulties with successful operation of devices such as the Tokamak Fusion Test Reactor are as follows: 1. It is necessary to have a sufficient density of hydrogen isotopes such as deuterium or tritium to permit the fusion reaction. However, this density is difficult to maintain eletrically because it is difficult to obtain a sufficient voltage gradient in the plasma to effectively add energy and thus increase the temperature of either the positive ions or the electrons. All attempts to obtain an electrical gradient cause an electron current to flow but do not add very much energy to the positive ions which are the particles which must have high velocity in order to obtain the collisions needed to produce the fusion reaction. 2. Since the deuterium or tritium gas density should be relatively high, it is difficult to purge gas impurities from the plasma container. The existence of these impurities reduces the probability of fusion reaction between particles since they absorb energy from the isotope ions without contributing to the possibility of a fusion reaction. The impurity problem is well known and is complicated by the fact that the energy density in the plasma must be extremely high, causing the vaporization of many solids which are used in constructing the apparatus. 3. The positive ions of deuterium and tritium which are expected to combine are all positively charged and therefore repel each other in the plasma. Consequently, it is difficult to obtain a collision which causes a fusion reaction rather than an elastic collision. Several thousand collisions are required at the correct velocity vector direction and magnitude in order to cause a single fusion reaction. In the past, attempts to solve this problem were simply efforts which add to the density and energy of the plasma to cause more collisions even though the probability of a fusion reaction was extremely low because of the random velocity vector directions of the particles. In order to add energy to the plasma, various heating methods are now being used in Tokamak machines. These include ohmic heating and neutral beam heating. Ohmic heating does not produce ion velocity vectors in the correct directions within the plasma to cause high energy collisions because when high fields are produced, the major velocity components are mostly in the same direction as that caused by the ohmic heating current flow. Consequently, ohmic heating of the gas encounters great difficulties of application. The use of neutral beam heating of the plasma and radio frequency heating are helpful but these require extremely large capital investment and complex equipment for the reactor. BRIEF DESCRIPTION OF THE INVENTION In accordance with the present invention, two ion beams preferably one of deuterium and one of tritium each having an appropriate relatively low energy are accelerated directly toward one another in vacuum. The beams can be moved linearly in an elongated vacuum chamber or can be rotated in counter-rotating directions relative to one another in circular paths. Preferably, but not necessarily, the two beams will be made up respectively of positive and negative ions, thus causing the intersecting ions to attract one another electrostatically and increasing the probability of a fusion collision. Energy which is produced by fusion of intersecting particles is removed as by a heat absorbing fluid which is circulated around the vacuum chamber. The heat absorbing fluid may be liquid lithium which can also serve as a source of tritium ions through conventional processing of the lithium. Note that ions other than deuterium and tritium can be used but deuterium and tritium are the preferred ions since they will undergo a fusion reaction at the lowest temperature known for various combinations of fusing particles. The present invention avoids the problems identified above in connection with previous fusion machines since applicant's device need not satisfy the Lawson criteria. There is no plasma and the number of free electrons is held to a low level. The production of energy in high vacuum in accordance with the invention is possible because of the relatively low energy density of the ions and the ability to employ fast vacuum pumping to remove neutral atoms and impurities, and also because of the absence of a need for a voltage gradient in the reaction chamber. The positive and negative hydrogen isotope ion beams are produced by well-known techniques. For example, the negative ion beam can be created by passing a positive ion beam through an alkali metal vapor such as sodium or cesium. A high percentage of the positive ions will then pick up two electrons and hold them long enough to be accelerated. The velocity vectors of the counter-moving beams may be controlled over a relatively narrow range in magnitude and direction so that there will be sufficient energy to cause the fusion reaction to occur but not so high that it will cause the fusing atoms to fly apart. The employment of the novel invention causes a substantial increase in the probability of continuing fusion reactions at relatively low total energy levels for the ion densities used in the novel method and apparatus.
	summary
	abstract	A method for improving resolution of X-ray radiography systems of the type used to obtain images of internal features of human bodies or to view contents of luggage articles, cargo containers and the like comprises positioning a plurality of baffle plates between the rear surface of an X-ray radiation detector array and a back stop used to limit transmitted X-ray radiation to a safe level. The baffle plates are made of a high atomic-number metal such as iron or lead which reduces by absorption, scattering or other attenuating processes the intensity of X-ray radiation back scattered from the back-stop onto the detector array, thus reducing noise contributions to signals output from detector elements of the array and thereby improving the quality of radiographic images formed from detector output signals. A back-scattered X-ray radiation attenuation apparatus according to the present invention utilizes pairs of horizontal upper and lower baffle plates disposed longitudinally rearward from upper and lower sides of individual X-ray radiation detector elements, or groups of elements, of a detector array, and optionally includes pairs of baffle plates disposed transversely to the horizontally disposed plates to thereby form an array of tubular collimatator elements which intercept and attenuate X-ray radiation scattered from locations on a back-stop on lateral sides of as well as above and below the detector elements.
	summary
	abstract	A method of making an anti-scatter X-ray grid device, and the X-ray grid device made therefrom, includes providing a substrate made of a material substantially non-absorbent of X-rays that includes channels therein; applying a layer, also of a substantially non-absorbent of X-rays material, onto a sidewall(s) of the channels, wherein the layer comprises a second material; and then applying a material substantially absorbent of X-rays into a portion of the channels, so as to define a plurality of X-ray absorbing elements. The present invention has been described in terms of specific embodiment(s), and it is recognized that equivalents, alternatives, and modifications, aside from those expressly stated, are possible and within the scope of the appending claims.
048572616	claims	1. In a nuclear reactor pressure vessel having a removable closure head with a plurality of ports projecting therethrough, and an upwardly extending shroud enclosing said ports, the shroud having a plurality of openings therein, a reactor vessel head area monitor comprising: (i) a video camera attached to the cooling shroud adjacent one of said openings; (ii) a lens operably attached to the camera such that the video camera receives video images of the reactor vessel head area within the shroud; and (iii) a light source attached to the shroud for illuminating the reactor vessel head area (i) a plurality of video cameras, one each attached to one of said doors of the shroud adjacent the aperture; (ii) a wide angled lens operably attached to each video camera such that said video cameras receive video images of the reactor vessel head area; (iii) a plurality of lamps for illuminating the reactor vessel head area, each of said lamps having a variable intensity, attached to each of said doors, two each attached adjacent to each video camera, one on either side of said video camera; (iv) means for selectively illuminating said lamps; (v) means for selectively varying the intensity of said illuminated lamps; and (vi) means for individually energizing each of said video cameras. (i) positioning a plurality of video cameras on said shroud adjacent to said openings; (ii) attaching a wide-angled lens to each of said video cameras such that said video cameras receive video images of the reactor vessel head area therethrough; (iii) placing a plurality of lamps, each having a variable intensity, adjacent to said video cameras for illuminating said ports; (iv) selectively illuminating at least one of said lamps; (v) selectively varying the intensity of said illuminated lamps; and (vi) individually energizing each of said video cameras to receive video images of the entire reactor vessel head area. 2. The reactor vessel head area monitor as recited in claim 1, wherein the light source comprises a plurality of lamps, each having a variable intensity, disposed about the circumference of the shroud, means for selectively illuminating each lamp, and means for varying the intensity of said lamps when illuminated. 3. The reactor vessel head area monitor as recited in claim 1, further comprising a case constructed of neutron shielding material, the case enclosing the camera and having an aperture therein such that the lens receives video images therethrough. 4. The reactor vessel head area monitor as recited in claim 3, further comprising means for circulating a flow of air around the video camera to dissipate heat therefrom. 5. The reactor vessel head area monitor as recited in claim 1, further including means for displaying said video images received by the video camera. 6. The reactor vessel head area monitor as recited in claim 5, further including means for retrievably storing said video images received by the video camera. 7. The reactor vessel head area monitor as recited in claim 1, wherein said openings in the shroud are viewing windows, the video camera being attached on an exterior surface thereof so as to receive video images of said ports of the reactor vessel head area. 8. In a nuclear reactor pressure vessel having a removable closure head with a plurality of ports projecting therethrough, and a shroud extending upwardly from said closure head and enclosing said ports, the shroud having a plurality of doors thereon and having an aperture therethrough, a reactor vessel head area monitoring system comprising: 9. The reactor vessel head area monitoring system as recited in claim 8, further comprising a case constructed of neutron shielding material enclosing each said video camera. 10. The reactor vessel head area monitoring system as recited in claim 9, further comprising means for circulating a flow of cooling air around each of said video cameras. 11. The reactor vessel head area monitoring system as recited in claim 8, further comprising means for displaying said video images received by each of said video cameras. 12. The reactor vessel head area monitoring system as recited in claim 11, further comprising means for retrievably storing said video images received by each of said video cameras. 13. The reactor vessel head area monitoring system as recited in claim 12, further comprising a case constructed of neutron shielding material enclosing each said video camera. 14. The reactor vessel head area monitoring system as recited in claim 13, further comprising means for circulating a flow of cooling air around each of said video cameras. 15. A method of monitoring a closure head of a nuclear reactor pressure vessel, the closure head having a plurality of ports projecting therethrough, and a shroud extending upwardly from said closure head and enclosing said ports which are monitored, the shroud having a plurality of openings therein, the method comprising the steps of: 16. The method as recited in claim 15, including the step of shielding each of said video cameras within a case of neutron shielding material, the case having an aperture therein such that the video camera receives video images therethrough. 17. The method as recited in claim 16, further including the step of directing a flow of air around each of said video cameras to dissipate heat therefrom. 18. The method as recited in claim 15, further including the step of displaying said video images received by each of said video cameras. 19. The method as recited in claim 18, further including the step of retrievably storing said video images received by each of said video cameras. 20. The method as recited in claim 19, further including the step of directing a flow of air around each of said video cameras to dissipate heat therefrom.
	claims	1. A three-dimensional grating magneto optical trap (3D GMOT) comprising:a single input light beam having its direction along a first axis, an area along a second and third axis that are both normal to the first axis, and a substantially flat input light beam intensity profile extending across its area;a circular, diffraction-grating surface positioned normal to the first axis and extending along the second and third axis; the circular, diffraction-grating surface having closely adjacent grooves arranged concentrically around a gap formed in the center of the circular, diffraction-grating surface;the circular, diffraction-grating surface configured to:diffract first-order light beams that intersect within an intersection region that lies directly above the gap, andsuppresses reflections and diffractions of all other orders; anda quadrupole magnetic field with its magnitude being zero within the intersection region;wherein the 3D GMOT is configured to trap a cold-atom cloud within the intersection region. 2. The 3D GMOT of claim 1, wherein each of the diffracted first-order light beam's intensity is between 15 and 35% of the input light beam's intensity. 3. A method for trapping a cold-atom cloud, the method comprising providing a three-dimensional grating magneto optical trap (3D GMOT), comprising:providing a first, single input light beam having its direction along a first axis, an area along a second and third axis that are both normal to the first axis, and a substantially flat input light beam intensity profile extending across its area;providing a circular, diffraction-grating surface positioned normal to the first axis and extending along the second and third axis; the circular, diffraction-grating surface having closely adjacent grooves arranged concentrically around a gap formed in the center of the circular, diffraction-grating surface;the circular, diffraction-grating surface configured to:diffract first-order light beams that intersect within an intersection region that lies directly above the gap, andsuppresses reflections and diffractions of all other orders; andproviding a quadrupole magnetic field with its magnitude being zero within the intersection region;wherein the 3D GMOT is configured to trap the cold-atom cloud within the intersection region. 4. The method of claim 3, wherein each of the diffracted first-order light beam's intensity is between 15 and 35% of the input light beam's intensity.
	abstract	A suspended basket includes a plurality of plates, tie rods, and adjustable length threaded tie rod couplings connecting threaded ends of the tie rods with threaded features of the plates. Control rod drive mechanisms (CRDMs) with CRDM motors are mounted in the suspended basket, which is suspended in a pressure vessel above a nuclear reactor core to control insertion of control rods into the reactor core. In one embodiment each adjustable length threaded tie rod coupling is a turnbuckle coupling that includes a sleeve threaded onto the threaded end of the tie rod and onto the threaded feature of the plate, and the sleeve is rotatable to adjust the position of the tie rod respective to the plate. Guide frames may be mounted in the suspended basket between the CRDMs and the nuclear reactor core to guide portions of the control rods withdrawn from the nuclear reactor core.
	description	1. Field of the Invention The present invention relates to a human phantom apparatus, a finger phantom apparatus, an apparatus for measuring a characteristic of an antenna using the phantom apparatus, an antenna apparatus, and a radio communication apparatus with the antenna apparatus. In particular, the present invention relates to a human phantom apparatus and a finger phantom apparatus which are used upon measuring a characteristic of an antenna apparatus, an apparatus for measuring a characteristic of an antenna apparatus using the same phantom apparatus, an antenna apparatus constituted based on measurement results of the apparatus for measuring the characteristic of the antenna apparatus, and a radio communication apparatus using the antenna apparatus. 2. Description of the Related Art In recent years, mobile communication systems, each using a radio communication apparatus such as a mobile phone or the like have been rapidly developed. Generally, the mobile phone is used in the vicinity of a human body, and therefore, it is important to highly accurately measure characteristics of an antenna of the mobile phone, in such a state that the mobile phone is attached to the human body. A conventional measurement of the characteristics of the antenna of the mobile phone has the following disadvantages. Since it has been difficult for a human subject to maintain his or her attitude, reproducibility is deteriorated. Due to great differences among human subjects, it is difficult to relatively compare measurement results with each other. For these reasons, the characteristics of the antenna of the mobile phone have been conventionally measured using a human phantom apparatus as disclosed in, for example, a first patent document of Japanese patent laid-open publication No. JP-P2000-082333-A, and a second patent document of Japanese patent laid-open publication No. JP-P2002-107396-A. According to the first patent document, for example, in order to provide a composite dielectric capable of mass-producing solid biological phantoms in short time at a lower manufacturing cost, and having uniformly stable electric characteristics, the composite dielectric used for a solid biological phantom is characterized by containing thermosetting resin of 40 to 90 volume % and electrically conductive powder of 10 to 60 volume % (100 volume % in all). According to the second patent document, for example, in order to measure the change in the characteristics due to a positional relationship between the antenna attached with the mobile phone and the human body or an ear, in particular, with higher accuracy, there is provided a human phantom apparatus that is constructed by a head section including ear sections, a body section, an arm section, a left hand section, and a moving means, and the human phantom is characterized by allowing the arm section to move by the moving means. The second patent document particularly provides the human phantom apparatus having an attitude for holding the mobile phone on the ear of the human phantom apparatus. The mobile phone is used as a conventional telephone, and further, the mobile phone is also used as a data terminal for transmitting and receiving E-mails and viewing web pages using WWW (Word Wide Web). The frequency increases of using the mobile phone in a user's attitude of holding the mobile phone by his hand in front of his chest. This attitude is referred to as a PDA (Personal Digital Assistance) attitude hereinafter. In order to establish a higher quality of telephone speech communication quality of the mobile phone even in these circumstances, it is necessary to measure the characteristics of the antenna of the mobile phone with higher accuracy in accordance with the positional relationship between the antenna and the human body. As disclosed by the second patent document, the conventional human phantom apparatus simulates an attitude in telephone speech communication of holding the mobile phone near the ear on the side of the head section, and is unable to measure the characteristics of the antenna in a PDA attitude. In the PDA attitude, the distance between the antenna of the mobile phone and the human body is larger than that that in the conventional attitude of the telephone speech communication. For this reason, it is disadvantageously difficult to highly accurately measure the characteristics of the antenna using the human phantom apparatus different from an actual human body in shapes of sections such as a shoulder, a chest, and an arm, in such a state that a radio wave radiated from a portable radio communication apparatus held in the PDA attitude is reflected and absorbed by the human phantom apparatus. In addition, since the human phantom apparatus includes a solid material such as composite dielectric or the like, it is disadvantageously difficult to highly accurately simulate a state of the adhesion between fingers and the mobile phone, in such a state that the human phantom apparatus holds the mobile phone. The electric characteristics of the human body change according to the radio frequency being used. In order to deal with this change, it is necessary to manufacture the human phantom apparatus by re-adjusting the composition ratio of the solid materials according to the radio frequency band. As a result, the manufacturing cost disadvantageously increases. Further, there has been desired a radio communication apparatus that includes at least two antennas, that performs diversity reception, and that can receive radio signals satisfactorily at levels larger than those of the prior art. It is an object of the present invention to provide a human phantom apparatus, a finger phantom apparatus, and an antenna characteristic measurement apparatus using the human phantom apparatus and the finger phantom apparatus capable of solving the above-mentioned conventional disadvantages, holding a radio communication apparatus such as a mobile phone or the like in a PDA attitude, and measuring a characteristic of an antenna of the radio communication apparatus with accuracy higher than that of the prior art. It is another object of the present invention to provide an antenna apparatus capable of solving the conventional disadvantages, and receiving a radio signal satisfactorily based on measurement results of the antenna characteristic measurement apparatus for use in a radio communication apparatus that includes at least two antennas and performs diversity reception, and a radio communication apparatus using the antenna apparatus. According to one aspect of the present invention, there is provided a human phantom apparatus with a body section, a head section connected with the body section, at least one shoulder section connected with the body section, and an arm section including a hand section. The arm section is connected with the shoulder section. Each of the body section, the head section, the at least one shoulder section, and the arm section is filled with a human body equivalent material. The human phantom apparatus has an attitude of holding a radio communication apparatus by the hand section of the arm section, so that the human phantom apparatus looks at a display unit of the radio communication apparatus in front of the body section. In the above-mentioned human phantom apparatus, the head section is preferably arranged to be inclined from a vertical direction of the human phantom apparatus. The above-mentioned human phantom apparatus preferably further includes a first rotational connecting device which rotatably connects the head section on the body section at a depression angle direction of the human phantom apparatus. The above-mentioned human phantom apparatus preferably further includes a second rotational connecting device which rotatably connects the hand section around the arm section at the depression angle direction of the human phantom apparatus so as to change an inclined angle of the radio communication apparatus with respect to a horizontal direction. The above-mentioned human phantom apparatus preferably further includes a first slidable connecting device which slidably connects the shoulder section with the arm section so as to change an interval between the body section and the hand section. The above-mentioned human phantom apparatus preferably further includes a second slidable connecting device which slidably connects the shoulder section with the body section substantially in a vertical direction of the human phantom apparatus. In the above-mentioned human phantom apparatus, the human phantom apparatus is preferably employed to measure a characteristic of an antenna of the radio communication apparatus. According to another aspect of the present invention, there is provided a finger phantom apparatus which includes a hollow fingertip section made of an elastic material, and a hollow finger root section made of a dielectric material. The fingertip section and the finger root section are filled with a human body equivalent material, and are sealed. According to a further aspect of the present invention, there is provided a finger phantom apparatus which includes a hollow fingertip section made of an elastic material, and a finger root section made of a solid phantom. The finger section is filled with a human body equivalent material. In the above-mentioned finger phantom apparatus, the finger phantom apparatus is preferably employed to measure a characteristic of an antenna of a radio communication apparatus. According to a still further aspect of the present invention, there is provided an antenna characteristic measurement apparatus which measures a characteristic of an antenna of the radio communication apparatus using the human phantom apparatus. The antenna characteristic measurement apparatus includes a control device. The control device measures the characteristic of the antenna of the radio communication apparatus, by changing at least one parameter selected from (a) an interval between the body section and the radio communication apparatus, (b) an inclined angle of the radio communication apparatus with respect to a horizontal direction, and (c) a height of the radio communication apparatus. In the above-mentioned antenna characteristic measurement apparatus, the human phantom apparatus preferably includes the finger phantom apparatus. In the above-mentioned antenna characteristic measurement apparatus, the characteristic of the antenna of the radio communication apparatus are preferably measured in such a state that the fingertip section is brought into contact with an input device of the radio communication apparatus. According to a still further aspect of the present invention, there is provided an antenna apparatus for use in a radio communication apparatus. The antenna apparatus includes at least two antennas. The two antennas are arranged in the radio communication apparatus, so that an absolute value d0 of a horizontal interval between the two antennas satisfies the following Equation:d0=λ/4+(nλ)/2, where λ is a wavelength of a radio wave to be used, and n is an integer equal to or larger than zero. According to a still further aspect of the present invention, there is provided an antenna apparatus for use in a radio communication apparatus. The antenna apparatus includes at least two antennas. The two antennas are arranged in the radio communication apparatus, so that an absolute value d0 of a horizontal interval between the two antennas, in such a state that the radio communication apparatus is inclined at a predetermined inclined angle with respect to a horizontal direction, satisfies the following Equation:d0=λ/4+(nλ)/2, where λ is a wavelength of a radio wave to be used, and n is an integer equal to or larger than zero. According to a further aspect of the present invention, there is provided a radio communication apparatus which includes the above-mentioned antenna apparatus. According to a still further aspect of the present invention, there is provided an antenna apparatus for use in a radio communication apparatus. The antenna apparatus includes at least two antennas including a first antenna and a second antenna. The first and second antennas are arranged in the radio communication apparatus, so that an absolute value d0 of a difference between (a) a horizontal interval between the body section of the human phantom apparatus and the first antenna and (b) a horizontal interval between the body section of the human phantom apparatus and the second antenna, in such a state that the radio communication apparatus is held by the hand section of the human phantom apparatus satisfies the following Equation:d0=λ/4+(nλ)/2, where λ is a wavelength of a radio wave to be used, and n is an integer equal to or larger than zero. According to a still further aspect of the present invention, there is provided an antenna apparatus for use in a radio communication apparatus. The antenna apparatus includes at least two antennas including a first antenna and a second antenna. The first and second antennas are arranged in the radio communication apparatus, so that an absolute value d0 of a difference between (a) a horizontal interval between the body section of the human phantom apparatus and the first antenna and (b) a horizontal interval between the body section of the human phantom apparatus and the second antenna, in such a state that the radio communication apparatus is held so as to be inclined at a predetermined inclined angle with respect to a horizontal direction by the hand section of the human phantom apparatus satisfies the following Equation:d0=λ/4+(nλ)/2, where λ is a wavelength of a radio wave to be used, and n is an integer equal to or larger than zero. According to a still further aspect of the present invention, there is provided a radio communication apparatus which includes the above-mentioned antenna apparatus. Accordingly, it is possible to faithfully simulate such a state that the radio communication apparatus is held in a PDA attitude, and to measure the characteristics of the antenna with accuracy higher than that of the prior art by measuring an antenna of the radio communication apparatus using the human phantom apparatus. Further, by designing dimensions of inner walls of respective sections of the human phantom apparatus based on standard dimensions of an adult male according to predetermined statistic data, it is possible to measure the characteristics of the antenna of the radio communication apparatus having larger universality. The human phantom apparatus is provided as a liquid phantom having a physiological saline solution, water, or an SAR solution filled into a dielectric container made of resin or the like. In this case, even if antenna measurement should be done for various radio frequencies, the characteristics of the antenna of the radio communication apparatus 111 can be measured only by filling a physiological saline solution, water, or an SAR solution according to electric properties of a human body for the respective radio frequencies. In addition, it is possible to greatly reduce a manufacturing cost as compared with that of a solid phantom made of a solid material. By making a position and an angle at which the radio communication apparatus is held adjustable by the sliding mechanism, it is possible to measure radiation characteristics of the antenna using the interval between the radio communication apparatus and the human phantom apparatus and the inclined angle of the radio communication apparatus as parameters. In addition, the attitude of the display unit of the radio communication apparatus can be adjusted to always face or oppose the head section of the human phantom apparatus, so that the human phantom apparatus looks at the display unit. Therefore, it is possible to measure the characteristics of the antenna of the radio communication apparatus with accuracy higher than that of the prior art. Further, when a plurality of antennas are arranged in the radio communication apparatus, they are arranged so that an absolute value of the difference between intervals “d1” and “d2” between the antennas and the body section of the human phantom apparatus, respectively, is λ/4 or a value obtained by adding a multiple of a natural number of λ/2 to λ/4, in such a state that the radio communication apparatus is held so as to be inclined at a predetermined inclined angle, and further, the antenna having a higher reception level in a propagation environment within a line of sight is selected as a transmission antenna. Then it is possible to improve a space diversity effect and to suppress deterioration of antenna sensitivity in the PDA attitude. Moreover, by employing the finger phantom apparatus having a container a tip end portion of which is made of an elastic material such as rubber, it is possible to highly accurately simulate such a state that a finger contacts with the antenna or the radio communication apparatus, and to measure the characteristics of the antenna with accuracy higher than that of the prior art. Preferred embodiments according to the present invention will be described below with reference to the attached drawings. The same reference numerals are used for components similar to each other. FIG. 1 is a front view which illustrates a configuration of a human phantom apparatus 101 according to the first preferred embodiment of the present invention. FIG. 2 is a side view which illustrates a configuration of the human phantom apparatus 101 shown in FIG. 1. FIG. 3 is a top view which illustrates a configuration of the human phantom apparatus 101 shown in FIG. 1. As shown in FIGS. 1 to 3, the human phantom apparatus 101 according to the first preferred embodiment is characterized by including a head section 102, a body section 103, a right shoulder section 104, a left shoulder section 107, and a right arm section 105 connected with the right shoulder section 104 and having a right hand section 106. The human phantom apparatus 101 is characterized by having a PDA attitude of holding a portable radio communication apparatus 111 by the right hand section 106 of the right arm section 105 in front of the body section 103, so that the human phantom apparatus 101 looks down at a liquid crystal display unit 111a of the portable radio communication apparatus 111. In this case, the PDA attitude means an attitude of holding the portable radio communication apparatus 111 by the right hand section 106 in front of the chest of the body section 103 of the human phantom apparatus 101, so that the human phantom apparatus 101 can operate the portable radio communication apparatus 111 such as a PDA (Personal Digital Assistant) or the like upon looking at the liquid crystal display unit 111a thereof. Referring to FIGS. 1 to 3, the body section 103 is formed integrally with a pedestal 108 so as to be mounted on the pedestal 108, and the head section 102 is formed integrally with the body section 103 so as to be mounted on the body section 103. The head section 102 is provided to be inclined from the vertical direction of the human phantom apparatus 101, which is parallel to the zenith direction, so that the human phantom apparatus 101 looks down at the liquid crystal display unit 111a of the portable radio communication apparatus 111, as described later in detail. The right shoulder section 104 is connected with an upper right side surface of the body section 103 through a shoulder section sliding mechanism including sliding sections 103a and 104b, so that the right shoulder section 104 is slidable and fixable substantially in the vertical direction, which is parallel to the up and down directions of the human phantom apparatus 101. In addition, the left arm section 107 is connected with an upper left side surface of the body section 103. By the sliding of the shoulder sliding mechanism including the sliding sections 103a and 104b, the height in the vertical direction of the hand section 106 that holds the portable radio communication apparatus 111 can be changed, so that the height of the portable radio communication apparatus 111 can be changed. Further, the right arm section 105 is connected with the right shoulder section 104 through an arm sliding mechanism that includes sliding sections 104c and 105b, so that the right arm section 105 is slidable and fixable in a horizontal direction which is parallel to the front and back direction or the back and forth direction of the human phantom apparatus 101. Further, the right hand section 106 is connected with a tip end of the right arm section 105 through a hand section rotation mechanism using a screw of a screw reception section 105c, so that the right hand section 106 is rotatable around an axis of the right arm section 105 in a depression angle direction, in which the human phantom apparatus 101 looks down at the liquid crystal display unit 111a. The surfaces of the head section 102, the body section 103, the right shoulder section 104, the right arm section 105, the right hand section 106, and the left shoulder section 107 are made of resin such as FRP (Fiber Reinforced Plastics) or the like so as to have a thickness of 2 to 8 mm. A solution of a medium having an electric constant close to that of a human body (e.g., a physiological saline solution or water (when the used radio frequency is relatively low)) or an SAR solution, as a human body equivalent material, is injected and filled into interiors of the head section 102, the right shoulder section 104, the right arm section 105, and the right hand section 106 through injection holes 102a, 104a, 105a, and 106a, respectively. The head section 102 is formed integrally with the body section 103 and inside hollows thereof are communicated each other, so that the solution injected from the injection hole 102a of the head section 102 is also filled into the interior of the body section 103. The SAR solution is a solution used to measure an SAR (Specific Absorption Rate) that is an electric power absorbed by a unit mass due to exposure of a living body such as a human or the like to an electromagnetic field, and is used as the human body equivalent material. At a used radio frequency f of, for example, 900 MHz, the SAR solution preferably includes sucrose of 56.6%, demineralized water of 40.92%, sodium chloride of 1.48%, hydroxyl cellulose of 1.0%, and germicide of 0.1%. In addition, at a used radio frequency f of, for example, 1900 MHz, the SAR solution preferably includes butyl Carbitol of 44.92%, demineralized water of 54.90%, and sodium chloride of 0.18%. In the present specification, symbol % indicates percentage of a volume content. The injection hole 102a of the head section 102 is formed in a vertex section of the head section 102, and this leads to prevention of mixture of the air when the solution is injected into the human phantom apparatus 101. FIG. 4 is a longitudinal sectional view which illustrates a configuration in the vicinity of a portion in which the right shoulder section 104 and the right arm section 105 of the human phantom apparatus 101 shown in FIG. 1 are engaged with each other. FIG. 5 is a side view which illustrates a configuration in the vicinity of the portion in which the right shoulder section 104 and the right arm section 105 of the human phantom apparatus 101 shown in FIG. 1 are engaged with each other. Referring to FIG. 4, the right shoulder section 104 is formed integrally with the sliding section 104c, and the right arm section 105 is formed integrally with the sliding section 105b. The sliding section 104c is inserted and engaged with the sliding section 105b. In this case, the right arm section 105 including the sliding section 105b is constituted to slide in the front and back directions of the human phantom apparatus 101 relative to the right shoulder section 104 including the sliding section 104c. As shown in FIGS. 4 and 5, a screw 109 penetrating the sliding section 105b and received by the sliding section 104c can fix the right arm section 105 including the sliding section 105b onto the right shoulder section 104 including the sliding section 104c. Further, the right shoulder section 104 including the sliding section 104b has a sliding mechanism similar to that of FIGS. 4 and 5 with respect to the body section 103 including the sliding section 103a. The right shoulder section 104 including the sliding section 104b slides in the vertical direction of the body section 103 including the sliding section 103a, and is fixed to the body section 103 including the sliding section 103a by a screw 110 of FIG. 2. FIG. 6 is a front view which illustrates such a state that the right shoulder section 104 is moved upward, the right arm section 105 is moved backward, and the right hand section 106 is rotated so that the human phantom looks down at the liquid crystal display unit 111a of the portable radio communication apparatus 111 at a low depression angle in the human phantom apparatus 101 shown in FIG. 1. FIG. 7 is a side view which illustrates a state of the human phantom apparatus 101 shown in FIG. 6. FIG. 8 is a top view which illustrates a state of the human phantom apparatus 101 shown in FIG. 6. As shown in FIGS. 6 to 8, a positional relationship among the portable radio communication apparatus 111, the head section 102, and the body section 103 can be easily adjusted. In this case, the sliding sections 103a and 104b serving as the shoulder sliding mechanism move the right shoulder section 104 upward, and the sliding sections 104c and 105b serving as the arm sliding mechanism move the right arm section 105 in the front direction of the human phantom apparatus 101. Further, the screw reception section 105c serving as a fingertip rotation mechanism rotates the right hand section 106a in a direction as indicated by an arrow 106A of FIG. 7, so that the human phantom apparatus 101 looks down at the liquid crystal display unit 111a of the portable radio communication apparatus 111 at the low depression angle. As a result, even if the user operates the portable radio communication apparatus 111 when making the portable radio communication apparatus 111 closer to his face, the liquid crystal display unit 111a of the portable radio communication apparatus 111 can be adjusted to have an angle at which the liquid crystal display unit 111a is visible relative to lines of eyes of the human phantom apparatus 101. In addition, the fingertip rotation mechanism can adjust the right hand section 106, so that the liquid crystal display unit 111a can always face or oppose to the head section 102. The human phantom apparatus 101 constituted as mentioned above has the PDA attitude of holding the portable radio communication apparatus 111 by the right hand section 106 of the right arm section 105 in front of the body section 103, so that the human phantom apparatus 101 looks down at the liquid crystal display unit 111a that serves as a display unit of the portable radio communication apparatus 111, i.e., so that lines of the eyes of the human phantom apparatus 101 reach the liquid crystal display unit 111a. Therefore, the PDA attitude can be faithfully simulated, and the characteristics of the antenna of the portable radio communication apparatus 111 can be measured with accuracy higher than that of the prior art. Furthermore, the human phantom is provided as a liquid phantom having the solution such as the physiological saline solution as filled into a dielectric container made of resin or the like. In this case, even if various radio frequencies are used, the characteristics of the antenna of the portable radio communication apparatus 111 can be similarly measured only by injecting and filling the solution according to the electric properties of the human body at the respective radio frequencies. Therefore, it is possible to remarkably reduce the manufacturing cost as compared with that of a solid phantom made of a solid material. In the first preferred embodiment, the injection holes 102a, 104a, 105a, and 106a are formed in the respective components 102, 104, 105, and 106. However, the present invention is not limited to this, and for example, a plurality of injection holes may be formed in each of the components 102, 104, 105, and 106. This makes it is possible to facilitate discharging the solution filled into the interiors of these components 102, 104, 105, and 106. In this case, it is important to provide each injection hole at a position which does not influence the measurement results. That is, it is important to form each injection hole at a position at which a positional relationship that the solution is present between each injection hole and the portable radio communication apparatus 111 is satisfied. As shown in FIG. 2, for example, it is preferable that the injection hole 104a is formed in an upper side surface of the right shoulder section 104, and that the injection hole 105a is formed in a central side surface of the right arm section 105. It is also preferable to form a drainage hole (not shown) in a lower end portion of the back of the body section 103. If the dimensions of the inner walls of the head section 102, the body section 103, the right shoulder section 104, the right arm section 105, the right hand section 106, and the left shoulder section 107 are designed based on standard dimensions of an adult male according to predetermined statistical data, it is possible to measure the characteristics of the antenna having a larger universality. By faithfully simulating an actual human body shape, it is possible to measure situations in which a radio wave radiated from the portable radio communication apparatus 111 as held in the PDA attitude is reflected and absorbed by the human phantom apparatus 101 with higher accuracy, and to measure an electromagnetic influence of the human body on the portable radio communication apparatus 111 with higher accuracy, than those of the prior art. FIG. 9 is a front view which illustrates a configuration of a human phantom apparatus 301 according to a modified preferred embodiment of the first preferred embodiment of the present invention. FIG. 10 is a side view which illustrates such a state that a head section 302 is caused to slide by a head section sliding and rotation mechanism to rotate the head section 302, so that a human phantom looks down at a liquid crystal display unit 111a of a portable radio communication apparatus 111 in the human phantom apparatus 301 shown in FIG. 9. The human phantom apparatus 301 according to the modified preferred embodiment of the first preferred embodiment is constituted so that a head sliding mechanism is provided between the head section 302 and a body section 303 and is fixed by a screw section 305. This makes it possible for the head section 302 can be rotated in the front and back directions, as indicated by an arrow 305A, so as to slide on a circular concave portion of an upper end portion of the body section 303, and to orient or direct lines of eyes of the human phantom apparatus 301 to a downward direction. Then the lines of eyes of the human phantom apparatus 301 can be adjusted so as to oriented toward the front direction relative to the liquid crystal display unit 111a of the portable radio communication apparatus 111, and so that the human phantom apparatus 301 can look down at the liquid crystal display unit 111a. Therefore, the characteristics of the antenna can be measured with accuracy higher than that of the prior art. In the preferred embodiment and the modified preferred embodiment thereof, there are described the human phantom apparatuses 101 and 301 each having the left and right shoulder sections 104 and 107. However, the present invention is not limited to this, and the human phantom apparatus may include at least one shoulder section so that a hand section of the shoulder section holds the portable radio communication apparatus 111. In the preferred embodiment and the modified preferred embodiment thereof, the instance of holding the portable radio communication apparatus 111 by the right hand section 106 is described. However, the present invention is not limited to this. Alternatively, the human phantom apparatus may be constituted to further include a left arm section and a left hand section connected with the left shoulder section 107 or include only the left arm section and the left hand section which are connected with the left shoulder section 107, and to hold the portable radio communication apparatus 111 by the left hand section. Further, the portable radio communication apparatus 111 may be held by the right and left hand sections. In this case, similar sliding mechanisms are provided between the left shoulder section 107 and the body section 103 and between the left shoulder section 107 and the left arm section, respectively, and further, a rotational mechanism is provided between the left arm section and the left hand section. In the preferred embodiment and the modified preferred embodiment thereof, the pedestal 108 is not necessarily provided. However, since the pedestal 108 can produce an effect of safety against overturning, the pedestal 108 is preferably provided as long as the pedestal 108 is large enough not to influence the characteristics of the antenna. Besides, a grip may be attached to the pedestal 108, and then, it is possible to facilitate moving the human phantom apparatus 101 or 301. In the preferred embodiment and the modified preferred embodiment thereof, upper halves of the human phantom apparatuses 101 and 103 are provided, respectively. However, the present invention is not limited to this. As long as the human phantom apparatus includes at least the respective sections shown in the preferred embodiment and the modified preferred embodiment thereof, the human phantom apparatus may be a standing whole body model or a sitting whole body model. In the preferred embodiment and the modified preferred embodiment thereof, the liquid phantom having the solution such as the solution of the medium having an electric constant close to that of the human body, e.g., the SAR solution injected into the interiors of the respective components is described. However, the present invention is not limited to this. The human phantom apparatus may be a solid phantom. In this case, materials of the solid phantom preferably include silicon emulsion of 50%, demineralized water of 29.97%, glycerin of 15%, agar of 5%, and sodium benzoate of 0.3%. In the preferred embodiment and the modified preferred embodiment thereof, the dimensions of the human phantom are designed as the standard dimensions of the adult male based on the predetermined statistical data. However, the present invention is not limited to this. The human phantom apparatus may be constituted based on standard dimensions of an adult female or average dimensions each separated by ages. By thus employing the human phantoms of various dimensions, it is possible to measure changes in the characteristics of the antenna due to the differences between individuals with higher accuracy. FIG. 11 is a cross-sectional view and a block diagram which illustrate a configuration of an antenna characteristic measurement system using a human phantom apparatus 101 according to a second preferred embodiment of the present invention. Referring to FIG. 11, the antenna characteristic measurement system is constituted so that a pedestal of the human phantom apparatus 101 is fixed onto a turntable 403 disposed on a floor of a radio wave darkroom 401, and so that the turntable 403 can be rotated by a motor 404. The rotation of the turntable 403 is controlled by a rotation controller 408. In addition, the human phantom apparatus 101, a portable radio communication apparatus 111, and the turntable 403 constitute a measurement target antenna 402. A receiving antenna 405 such as a Yagi-Uda antenna, a beam antenna or the like is disposed at a position where the antenna 405 is opposed to the measurement target antenna 402 in the radio wave darkroom 401. At the time of measuring the characteristics of the antenna, the turn table 403 is rotated, a radio wave is radiated from the portable radio communication apparatus 111, the radiated radio wave is received by the reception antenna 405, then a radio signal of the received radio wave is received by a radio receiver 406, the received radio signal is subjected to processings such as high frequency amplification, frequency transformation, and detection, and thereafter, a detected electric signal is inputted to a system controller 407 including a network analyzer. The system controller 407 outputs signals such as a measurement start control signal, a measurement end control signal or the like to the rotation controller 408, measures the characteristics of the antenna, such as radiation pattern characteristics or input impedance characteristics, of the antenna 402 of the portable radio communication apparatus 111, and displays measurement results on a CRT display unit 409. In this case, as shown in FIG. 12, (a) an interval “d” between the portable radio communication apparatus 111 attached to the hand section 106 of the human phantom apparatus 101 and the body section 106 of the human phantom apparatus 101 having the PDA attitude, and (b) an inclined angle θ (which is a rotational angle from the X axis on the XZ plane of FIG. 12; this angle is referred to as an inclined angle hereinafter) of the portable radio communication apparatus 111 with respect to a depression angle direction of the human phantom apparatus 101 are adjusted to have constant values, respectively. By thus measuring the radiation pattern characteristics or impedance characteristics of the antenna included in the portable radio communication apparatus 111 using the interval “d” between the human phantom apparatus 101 and the portable radio communication apparatus 111 and the inclined angle θ as parameters, it is possible to measure influences of a human body onto the portable radio communication apparatus 111 with higher accuracy. The radiation pattern characteristics mean herein electric power antenna gain directional characteristics with respect to an arbitrary cut surface. The characteristics of the antenna according to the present invention are not limited to this, and may be antenna characteristics such as a radiation efficiency, an effective gain, a diversity antenna gain, a complex directivity gain characteristics including phase information, a correlation coefficient, or the like, which are calculated from the electric power antenna gain directional characteristics. FIG. 13 is a perspective view which illustrates a shape and a size of a portable radio communication apparatus 501 used in the antenna characteristic measurement system shown in FIG. 11. FIG. 14 is a graph which illustrates measurement results of measuring the antenna characteristics using the antenna characteristic measurement system shown in FIG. 11, and which illustrates a radiation efficiency of an antenna of the portable radio communication apparatus 501 with respect to the interval “d”. FIG. 15 is a graph which illustrates measurement results of measuring the characteristics of the antenna using the antenna characteristic measurement system shown in FIG. 11, and which illustrates an antenna gain of the antenna of the portable radio communication apparatus 501 in the +X direction with respect to the interval “d”. FIG. 12 illustrates a positional relationship and a coordinate system between the human phantom apparatus 101 and the portable radio communication apparatus 501 serving as a terminal model. Referring to FIG. 13, the portable radio communication apparatus 501 serving as the terminal model is constituted to include a rectangular-parallelepiped-shaped metal housing 502 having a length of 12.5 cm, a width of 3.5 cm, and a thickness of 2 cm, and a quarter-wave monopole antenna 503 having a length of 8.3 cm. The quarter-wave monopole antenna 503 is arranged on an upper end portion of the metal housing 502 in parallel along the longitudinal direction of the metal housing 502. An electric power of radio signal is supplied to the quarter-wave monopole antenna 503 from a feeding point 504 located in a connection section located on the upper end portion of the metal housing 502. Further, referring to FIG. 12, the portable radio communication apparatus 501 serving as the terminal model is attached to and held by the hand section 106 of the human phantom apparatus 101, so that the interval between the feeding point 504 and a body section 103 of the human phantom apparatus 101 in the X direction is set to a value of “d”, and so that the depression angle as rotated from the X axis to the Z axis direction is set to 50 degrees. FIG. 14 illustrates measurement results of the radiation efficiency measured by the antenna characteristic measurement system shown in FIG. 11 if the interval “d” is changed to 13, 16, 20, 25, and 30 (cm) in such a state that the hand section 106 of the human phantom apparatus 101 holds the portable radio communication apparatus 501 serving as the terminal model. FIG. 15 illustrates measurement results of the directivity gain in the +X direction at a measurement frequency of 900 MHz. As is apparent from FIGS. 14 and 15, the radiation efficiency of the antenna of the portable radio communication apparatus 501 is more improved as the interval “d” is larger, whereas the antenna gain in the +X direction periodically or cyclically changes relative to the change in the interval “d”. In the example shown in FIG. 15, at the interval “d” of about 23, 39, and 55 cm, the maximum antenna gain of about 0 dBi is obtained. At the interval “d” of about 14, 32, and 48 cm, the minimum antenna gain of about −10 dBi is obtained. As can be seen, the large change in the antenna gain in the +X direction relative to the change in the radiation efficiency represents that the human phantom apparatus 101 functions in a manner similar to that of a reflector plate of a corner reflector antenna. In other words, if the total length of the path from a location when the radio wave having a wavelength of λ is radiated from the antenna through a location when it is reflected by the human phantom apparatus 101 to a location when it is returned to the antenna is λ/2, then the radiated radio wave and the incident radio wave after being reflected are opposite in phase at the position of the antenna to be cancelled by each other. If the total length of the path is A, the radio waves are equal in phase, so that these radio waves are summed up. These relations can be expressed by, for example, the following Equations (1) and (2):d=λ/4+(nλ)/2 (1), andd=(nλ)/2 (2). In the Equations (1) and (2), “n” denotes an integer equal to or larger than zero. The Equation (1) represents such a case where the directivity gain in the +X direction is the minimum. The Equation (2) represents such a case where the directivity gain in the +X direction is the maximum. Actually, however, since the shape of the human body has irregularities, an absolute value of the interval “d” is not strict. Therefore, it is rather important to periodically or cyclically repeat high and low gains at an interval of λ/2. This is evident from FIG. 15. With the used frequency f of, for example, 900 MHz, λ/2 is 16.7, which is an intensifying condition based on the Equation (2). In FIG. 15, at the interval “d” of 20 cm, the antenna gain in the +X direction is the maximum; however, at the interval “d” of 13.30 cm, the antenna gain in the +X direction is the minimum. It is understood from FIG. 15 that a change amount of the interval “d” at this time is 17 cm corresponding to λ/2. As can be seen from the above, as shown in FIG. 18, when a plurality of antennas 1303 and 1305 is arranged on the portable radio communication apparatus 111, the respective antennas 1303 and 1305 are arranged at positions of the maximum antenna gain and the minimum antenna gain so that the antenna at one position has the minimum antenna gain, and the antenna at the other position always has the maximum antenna gain, respectively, namely, so that the absolute value d0=\|d1−d2\| of the difference between intervals “d1” and “d2” between the respective antennas 1303 and 1305 and the body section 103 of the human phantom apparatus 101 (the difference between the intervals d1 and d2 in the horizontal direction, in such a state that the portable radio communication apparatus 111 is held and inclined at the inclined angle of, for example, 50 degrees in FIG. 18) is λ/4, 3λ/4, 5λ/4, 7λ/4, . . . , that is, so that the absolute value d0 of the difference between the intervals “d1” and “d2” satisfies the following Equation (3). In this case, it is possible to improve the diversity effect with respect to the +X axis direction and to thereby greatly improve practical reception sensitivity and transmission radiation characteristics of the radio communication apparatus 111:d0=λ/4+(nλ)/2 (3). In the Equation (3), “n” denotes an integer equal to or larger than zero. Referring to FIG. 18, the positions of the body section 103 when the intervals “d1” and “d2” are measured actually are different from each other, respectively, between the intervals “d1” and “d2”, namely, they are slightly different from each other in the horizontal direction. However, when designing the antenna position of the portable radio communication apparatus 111, the positional difference may be set to substantially zero, and the Equation (3) may be applied. However, if the positions of the two antennas in the vertical direction in the portable radio communication apparatus 111 are greatly different from each other, it is necessary to apply the Equation (3) in light of the actual intervals “d1” and “d2” in the horizontal direction due to the difference in the positions of the body section. It is to be noted that, when designing the portable radio communication apparatus 111, the size of an actual user, a standard size, or a specific size instead of the body section 103 of the human phantom apparatus 101 may be considered. Furthermore, if the portable radio communication apparatus and a base station are located within a line of sight, for example, at hot spots such as those at a railway station, a park or the like in a propagation environment within a line of sight, it can be easily supposed that a time occupation rate of the antenna having a high reception level when diversity reception is carried out. Therefore, by using the antenna having a higher reception level as a transmission antenna, the telephone speech quality of the potable radio communication apparatus can be further improved. In this case, it is more effective when the absolute value of the difference between the intervals “d1” and “d2” between the respective antennas and the human body is λ/4. In case of an application in the 2 GHz band, for example, λ/4 corresponds to an interval of 3.75 cm. Therefore, when the two antennas are arranged at an interval of 3.75 cm, and the antenna having a higher reception level is used as the transmission antenna, then it is possible to suppress deterioration of the antenna sensitivity that depends on the PDA attitude of the portable radio communication apparatus as compared with the arrangement of the antennas at an interval of 7.5 cm. The same thing is true for an application in a 5 GHz band. Then λ/4 corresponds to an interval of 1.5 cm, and therefore, when the two antennas are arranged at an interval of 1.5 cm or 4.5 cm and the antenna having a higher reception level is used as the transmission antenna, then it is possible to suppress the deterioration of the antenna sensitivity that depends on the PDA attitude of the portable radio communication apparatus, as compared with the arrangement of the antennas at an interval of 3 cm or 6 cm which is a multiple of a natural number of λ/2. In case of an application in an 8 GHz band, λ/4 corresponds to an interval of 1 cm or less. Therefore, utilizing the periodic or cyclic change in the antenna gain, the antennas may be arranged at an interval of, for example, 3λ/4 or 5λ/4. In this case, the same advantageous effects can be attained. FIG. 16 is a perspective view which illustrates a shape and a size of a portable radio communication apparatus 1301 that includes two antennas 1303 and 1305 according to a first implemental example of the present invention. Referring to FIG. 16, a monopole antenna 1303 having a feeding point 1304 in a corner of an upper end surface of a metal housing 1302 of the portable radio communication apparatus 1301 is provided so as to extend in the vertical direction. On the other hand, a planar inverted-F antenna 1305 is provided on an upper left portion of a front surface of the metal housing 1302 so as to be in parallel to the front surface thereof. A position 1305q located on the surface of the planar inverted-F antenna 1305 to be slightly shifted from the central portion of the surface is connected with a feeding point 1306 on the front surface through a feeding conductor 1305qr, and a position 1305p of a part of an edge of an upper end portion of the planar inverted-F antenna 1305 is short-circuited so as to be grounded to the metal housing through a short-circuit conductor 1305pr. The two antennas 1303 and 1305 are connected with a radio communication circuit (not shown) through the feeding points 1304 and 1306, respectively. The radio communication circuit includes a radio receiver, a radio transmitter, a diversity control circuit for carrying out diversity reception and diversity transmission using the two antennas 1303 and 1305, and a controller that controls the respective components of the circuit. FIG. 17 is a side view which illustrates a horizontal interval “D” between the feeding points 1304 and 1306 of the two antennas 1303 and 1305, respectively, in such a state that the portable radio communication apparatus 1301 shown in FIG. 16 is held so as to be inclined at an inclined angle of 50 degrees when the potable radio communication apparatus 1301 is held by the human phantom apparatus 101. FIG. 17 illustrates the horizontal interval “D” between the feeding points 1304 and 1306 of the respective antennas 1303 and 1305 in such a state that the portable radio communication apparatus 1301 is held so as to be inclined at the inclined angle of 50 degrees and held. The respective antennas 1303 and 1305 are located at the positions of the maximum antenna gain and the position of the minimum antenna gain, respectively, (namely, the antenna at one position has minimum antenna gain, the antenna at the other position always has maximum antenna gain), so that the above-defined interval “D” becomes λ/4, 3λ/4, 5λ/4, 7λ/4, . . . , as mentioned above when the positions of the body section 103 in the horizontal direction which are reference points of the intervals “d1” and “d2” substantially coincide with each other in FIG. 18, namely, becomes the right side of the Equation (3), or, so that the absolute value d0=D of the difference between the intervals “d1” and “d2” shown in FIG. 18 satisfies the Equation (3). In this case, it is possible to improve the diversity effect with respect to the +X axis direction. It is noted that the inclined angle θ in the horizontal direction is not limited to 50 degrees but may be any inclined angle at which the user holds the portable radio communication apparatus 111 when inclining the portable radio communication apparatus 111. The horizontal inclined angle is set preferably to an angle in a range from 20 to 70 degrees, more preferably to an angle in a range from 30 to 60 degrees. Further, the present invention is not limited to this, and the absolute value d0 of the difference between the intervals may be set when the portable radio communication apparatus 111 is not inclined, namely, at the inclined angle θ of 90 degrees. FIG. 19 is a perspective view which illustrates a shape and a size of a portable radio communication apparatus 1401 that includes two antennas 1403 and 1405 according to a second implemental example of the present invention. Referring to FIG. 19, the housing antennas 1403 and 1045 each made of a rectangular conductor pattern are formed in the vicinity of an upper end portion and that of a lower end portion of a rear surface (on a front surface opposed to which, a liquid crystal display unit and a keypad are formed) of a resin housing 1402 of the portable radio communication apparatus 1401, respectively. A feeding point 1404 of the housing antenna 1403 is located so as to be closer to the upper end portion, whereas a feeding point 1406 of the housing antenna 1405 is located so as to be closer to the lower end portion. FIG. 20 is a side view which illustrates a horizontal interval “D” between the feeding points 1404 and 1406 of the two antennas 1403 and 1405, respectively, in such a state that the portable radio communication apparatus 1401 shown in FIG. 19 is inclined at an inclined angle of 50 degrees when the portable radio communication apparatus 1401 is held by the human phantom apparatus 101. FIG. 20 illustrates the horizontal interval “D” between the feeding points 1404 and 1406 of the respective antennas 1403 and 1405 when the portable radio communication apparatus 1403 is inclined at the inclined angle of 50 degrees and held. The respective antennas 1403 and 1405 are located at the positions of the maximum antenna gain and the position of the minimum antenna gain, respectively, (namely, the antenna at one position has minimum antenna gain, the antenna at the other position always has maximum antenna gain), so that the above-defined interval “D” becomes λ/4, 3λ/4, 5λ/4, 7λ/4, . . . , as mentioned above when the positions of the body section 103 in the horizontal direction which are reference points of the intervals “d1” and “d2” substantially coincide with each other in FIG. 18, namely, becomes the right side of the Equation (3), or, so that the absolute value d0=D of the difference between the intervals “d1” and “d2” shown in FIG. 18 satisfies the Equation (3). In this case, it is possible to improve the diversity effect with respect to the +X axis direction. In the second preferred embodiment as mentioned above, when changing the interval “d” and the inclined angle θ, the characteristics of the antenna of the portable radio communication apparatus 111 are measured. However, the present invention is not limited to this. The characteristics of the antenna of the portable radio communication apparatus 111 may be measured by changing a vertical height of the portable radio communication apparatus 111 using the shoulder sliding mechanism that includes the sliding sections 103a and 104b. That is, in the measurement of the characteristics of the antenna of the portable radio communication apparatus 111, the characteristics of the antenna may be changed by changing at least one parameter selected from the interval “d”, the inclined angle θ, and the height. FIG. 21 is a perspective view which illustrates an appearance of a finger phantom apparatus 601 according to the third preferred embodiment of the present invention when a physiological saline solution 606 is injected into the finger phantom apparatus 601. FIG. 22 is a perspective view which illustrates an appearance of the finger phantom apparatus 601 shown in FIG. 21 when the physiological saline solution 606 is not injected into the finger phantom apparatus 601. FIG. 23A is a side view which illustrates a configuration of a finger phantom root section 602 of the finger phantom apparatus 601 shown in FIG. 21. FIG. 23B is a side view which illustrates a configuration of a screw section 602b engaged with the finger phantom root section 602 shown in FIG. 23A. FIG. 24 is a side view which illustrates a configuration of a circular cylindrical member 603 with which the finger phantom root section 602 shown in FIG. 23A is engaged. As shown in FIGS. 21, 22, 23A and 23B, the finger phantom apparatus 601 of the present preferred embodiment is characterized by including the hollow finger phantom root section 602, the hollow circular cylindrical member 603, and a fingertip section 604 including a hollow container made of an elastic material such as rubber or the like. Referring to FIGS. 23A and 23B, the screw section 602a is formed on a left tip end of the finger phantom root section 602, and a screw reception section 602c is formed on a right tip end of the section 602. A physiological saline solution or an SAR solution, for example, is injected so as to be filled into the finger phantom root section 602 as a human body equivalent material. By screwing the screw section 602 with the screw reception section 602c, a right end portion of the finger phantom root section 602 is sealed. Referring to FIG. 24, the circular cylindrical member 603 is a hollow circular cylindrical member made of resin such as acryl, polypropylene or the like. A screw reception section 603a is formed in the circular cylindrical member 603. A ring-shaped groove having a diameter smaller than an outer diameter of the circular cylindrical member 603 is formed in a fingertip fixing section 603b provided in the vicinity of one end portion or a left end portion of the circular cylindrical member 603. As shown in FIGS. 21 and 22, by fitting a ring-shaped stopper 605 into this groove on the circular cylindrical member 603 through the fingertip section 604, the fingertip section 604 is fixed onto the circular cylindrical member 603 by the stopper 605. In the finger phantom apparatus 601 shown in FIG. 22, the finger phantom root section 602 is inserted into the circular cylindrical member 603 to screw the screw section 602a of the circular cylindrical member 603 with the screw reception section 603a of the finger phantom root section 602. In addition, the screw section 602b is inserted into the screw reception section 602c of the finger phantom root section 602 to screw the screw section 602b with the screw reception section 602c, and the fingertip section 604 is faded away. Next, the screw section 602b is unscrewed, the physiological saline solution 606 or the SAR solution is filled into the fingertip section 604, the circular cylindrical member 603, and the finger phantom root section 602, thereafter, the screw section 602b is screwed, and this leads to that the fingertip section 604 is fully filled so as to be sealed as shown in FIG. 21. FIG. 25 is a front view which illustrates such a state that the finger phantom apparatus 601 shown in FIG. 21 is brought into contact with an antenna 702 of a folding portable radio communication apparatus 702. FIG. 26 is a perspective view which illustrates such a state that a real thumb 703 contacts with the antenna 702 shown in FIG. 25. In case of the conventional solid phantom or liquid phantom using a hard container made of FRP resin or the like, the contact portion of the phantom with the antenna 702 is limited to only a part of the antenna 702. Due to this, it is extremely difficult to faithfully simulate such a state that the actual thumb contacts with the antenna 702 as shown in FIG. 26. In contrast, there will be considered an instance in which the finger phantom apparatus 601 including the fingertip section 604 made of the elastic material such as rubber or the like is brought into contact with the antenna 702 of the portable radio communication apparatus 701 as shown in FIG. 25. The portable radio communication apparatus 701 is constituted so that an upper housing 710 and a lower housing 720 are foldable through a hinge section 730. A liquid crystal display unit 711 is arranged in a central portion of an inner side surface of the upper housing 710, and a sound hole section 712 for outputting a voice produced from a loudspeaker is formed above the liquid crystal display unit 711. In addition, a keypad section 721 including a key 222 and serving as input means is arranged in a central portion of the lower housing 720, and a microphone 723 is arranged below the keypad section 721. Further, the antenna 702 is arranged to extend upward so as to protrude from an upper left end portion of the lower housing. Referring to FIG. 25, when the fingertip section 604 is brought into contact with the antenna 702 using the finger phantom apparatus 601 including the fingertip section 604 made of the elastic material such as rubber or the like, a part of the fingertip section 604 in contact with the antenna 702 is depressed in accordance with a contact pressure. Therefore, it is possible to simulate almost the same state as or similar state to that of the actual finger, and to measure the characteristics of the antenna 702 with accuracy higher than that of the prior art. In addition, the thickness of the container of the fingertip section 604 can be reduced as compared with that of the conventional liquid phantom. Therefore, it is possible to be closer to an actual contact state, and to measure the characteristics of the antenna 702 with accuracy higher than that of the prior art. FIG. 27 is a perspective view which illustrates an appearance of a finger phantom apparatus 801 according to a modified preferred embodiment of a third preferred embodiment of the present invention. FIG. 28 is a side view which illustrates an appearance of a finger phantom root section 802 shown in FIG. 27. Referring to FIGS. 27 and 28, the finger phantom apparatus 801 according to the modified preferred embodiment of the third preferred embodiment is characterized by including the finger phantom root section 802 made of a solid phantom material such as composite dielectric or the like, instead of the finger phantom root section 602 shown in FIG. 21. A screw section 802a is provided on a left end portion of the finger phantom root section 802. The screw section 802a is inserted into and screwed with a screw reception section 603a of a circular cylindrical member 603. The solid phantom material preferably includes silicon emulsion of 50%, demineralized water of 29.97%, glycerin of 15%, agar of 5%, and sodium benzoate of 0.3%. Even in the finger phantom apparatus 801 constituted as mentioned above, a fingertip section 604 that is a section in contact with an antenna or a portable radio communication apparatus is the liquid phantom having a physiological saline solution 606 filled into a container made of an elastic member such as rubber. The finger phantom apparatus 801 according to the modified preferred embodiment of the third preferred embodiment exhibits the same function and advantageous effects as those of the third preferred embodiment. FIG. 29 is a perspective view which illustrates an appearance of a finger phantom apparatus 901 according to a fourth preferred embodiment of the present invention. FIG. 30 is a side view which illustrates a configuration of a finger phantom root section 902 shown in FIG. 29. FIG. 31 is a side view which illustrates a configuration of a screw section 902b engaged with a screw reception section 902c of the finger phantom root section 902 shown in FIG. 30. FIG. 32 is a top view which illustrates a configuration of the finger phantom root section 902 shown in FIG. 30. FIG. 33 is a side view which illustrates a configuration of a circular cylindrical member 902 shown in FIG. 29. The finger phantom apparatus 901 according to the fourth preferred embodiment simulates a thumb, and is characterized by including the hollow finger phantom root section 902, the hollow circular cylindrical member 903, and the hollow fingertip section 904 having a container made of an elastic material such as rubber or the like. A physiological saline solution 906 is filled into the finger phantom root section 902 having the screw section 902a provided on a left tip end. The screw section 902b formed at the highest position on an upper end portion of the finger phantom root section 902 is screwed with the screw reception section 902c serving as an injection hole for injecting the physiological saline solution 906. In addition, the screw section 902a is provided on the left side end portion of the finger phantom root section 902. Further, a screw reception section 903a is provided on a right side end portion of the hollow circular cylindrical member 903 made of resin such as acryl or polypropylene. A small ring-shaped groove having a diameter smaller than an outside diameter of the circular cylindrical member 903 is formed in a finger fixing section 903b in the vicinity of the screw reception section 903a. Referring to FIG. 29, by fitting a ring-shaped stopper 905 into this groove on through the fingertip section 904, the fingertip section 904 is fixed to the circular cylindrical member 903 by the stopper 905. In addition, the physiological saline solution 906 is filled into the fingertip section 904 and the circular cylindrical member 903, then the finger phantom root section 902 is inserted into the circular cylindrical member 903, and the screw section 902a is screwed with the screw reception section 903a, and this leads to that the finger phantom apparatus 901 is sealed. FIG. 34 is a front view which illustrates such a state that a folding portable radio communication apparatus 701 is held by the finger phantom apparatus 901 shown in FIG. 29 and a hand section 1001 of hand phantom, so that a lower housing 720 of the portable radio communication apparatus 701 is sandwiched between the finger phantom apparatus 901 and the hand section 1001 of hand phantom when a keypad section 721 serving as an input means or an input device and provided on the lower housing 720 of the portable radio communication apparatus 701 is pressed by the finger phantom apparatus 901. Referring to FIG. 34, by holding the folding portable radio communication apparatus 701 constituted in a manner similar to that of FIG. 25 by the finger phantom apparatus 901 constituted as mentioned above and the hand section 1001 of hand phantom, so that the lower housing 720 of the portable radio communication apparatus 701 is sandwiched between the finger phantom apparatus 901 and the hand section 1001 of hand phantom when a key 722 serving as the input means and provided on the lower housing 720 of the portable radio communication apparatus 701 is pressed by the fingertip section 904 of the finger phantom apparatus 901, it is possible to highly accurately simulate such a state that E-mails or the like are actually transmitted and received using the portable radio communication apparatus 701, to ensure good reproducibility, and measure the characteristics of the antenna with higher accuracy. Further, by using a hand section including the hand section 1001 of hand phantom and the finger phantom apparatus 901 as right fingers of the human phantom apparatus described in the preceding preferred embodiments, it is possible to simulate a PDA attitude more faithfully, and to measure the characteristics of the antenna with accuracy higher than that of the prior art. In the preferred embodiments mentioned so far, the physiological saline solution 906 is used as the human body equivalent material. However, the present invention is not limited to this. The water or the SAR solution may be used instead of the physiological saline solution 906 as mentioned above. The finger phantom apparatus according to each of the third preferred embodiment, the modified preferred embodiment thereof, and the fourth preferred embodiment may be used in the human phantom apparatus according to the first preferred embodiment or to the antenna characteristic measurement system according to the second preferred embodiment. In the preferred embodiments mentioned so far, the portable radio communication apparatus is used. However, the present invention is not limited to this. The present invention may be applied to various types of radio communication apparatuses. As mentioned so far, the human phantom apparatus according to the present invention is a human phantom apparatus including: a body section, a head section connected with the body section, at least one shoulder section connected with the body section. and an arm section connected with the at least one shoulder section and including a hand section. In this case, each of the body section, the head section, the at least one shoulder section, and the arm section filled with a human body equivalent material, and the human phantom apparatus has an attitude of holding a radio communication apparatus by the hand section of the arm section, so that the human phantom apparatus looks at a display unit of the radio communication apparatus in front of the body section. Accordingly, it is possible to faithfully simulate such a state that the radio communication apparatus is held in a PDA attitude, and to measure the characteristics of the antenna with accuracy higher than that of the prior art by measuring an antenna of the radio communication apparatus using this human phantom apparatus. Further, by designing dimensions of inner walls of respective sections of the human phantom apparatus based on standard dimensions of an adult male according to predetermined statistic data, it is possible to measure the characteristics of the antenna having a larger universality. The human phantom apparatus is provided as a liquid phantom having a physiological saline solution, water, or an SAR solution filled into a dielectric container made of resin or the like. In this case, even if various frequencies are used, the characteristics of the antenna of the radio communication apparatus 111 can be measured only by filling a physiological saline solution, water, or an SAR solution according to electric properties of a human body at the respective frequencies. In addition, it is possible to greatly reduce the manufacturing cost as compared with that of a solid phantom made of a solid material. By making the position and the angle when the radio communication apparatus is held adjustable by the sliding mechanism, it is possible to measure the radiation characteristics of the antenna using the interval between the radio communication apparatus and the human phantom apparatus and the inclined angle of the radio communication apparatus as parameters. In addition, the attitude of the display unit of the radio communication apparatus can be adjusted to always face or oppose to the head section of the human phantom apparatus, so that the human phantom apparatus looks at the display unit. Therefore, it is possible to measure the characteristics of the antenna of the radio communication apparatus with accuracy higher than that of the prior art. Further, when a plurality of antennas is arranged in the radio communication apparatus, the respective antennas are arranged so that an absolute value of the difference between intervals “d1” and “d2” between the antennas and the body section of the human phantom apparatus, respectively, is λ/4 or a value obtained by adding a multiple of a natural number of λ/2 to λ/4, in such a state that the radio communication apparatus is held so as to be inclined at a predetermined inclined angle, and so that the antenna having a higher reception level in a propagation environment within a line of sight is selected as a transmission antenna. In this case, it is possible to improve the diversity effect and to suppress deterioration of antenna sensitivity in the PDA attitude. Moreover, by employing the finger phantom apparatus having a container made having a tip end portion made of an elastic material such as rubber, it is possible to highly accurately simulate such a state that the finger contacts with the antenna or the radio communication apparatus, and to measure the characteristics of the antenna with accuracy higher than that of the prior art. Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.
	description	1. Field of the Invention This invention relates generally to an industrial process, and, more particularly, to applying a self-adaptive filter to a drifting industrial process, such as a semiconductor fabrication process. 2. Description of the Related Art There is a constant drive within the semiconductor industry to increase the quality, reliability and throughput of integrated circuit devices, e.g., microprocessors, memory devices, and the like. This drive is fueled by consumer demands for higher quality computers and electronic devices that operate more reliably. These demands have resulted in a continual improvement in the manufacture of semiconductor devices, e.g., transistors, as well as in the manufacture of integrated circuit devices incorporating such transistors. Additionally, reducing the defects in the manufacture of the components of a typical transistor also lowers the overall cost per transistor as well as the cost of integrated circuit devices incorporating such transistors. Generally, a set of processing steps is performed on a group of wafers, sometimes referred to as a “lot,” using a variety of processing tools, including photolithography steppers, etch tools, deposition tools, polishing tools, rapid thermal processing tools, implantation tools, etc. The technologies underlying semiconductor processing tools have attracted increased attention over the last several years, resulting in substantial improvements. One technique for improving the operation of a semiconductor processing line includes using a factory wide control system to automatically control the operation of the various processing tools. The manufacturing tools communicate with a manufacturing framework or a network of processing modules. Each manufacturing tool is generally connected to an equipment interface. The equipment interface is connected to a machine interface that facilitates communications between the manufacturing tool and the manufacturing framework. The machine interface can generally be part of an Advanced Process Control (APC) system. The APC system initiates a control script based upon a manufacturing model, which can be a software program that automatically retrieves the data needed to execute a manufacturing process. Often, semiconductor devices are staged through multiple manufacturing tools for multiple processes, generating data relating to the quality of the processed semiconductor devices. During the fabrication process, various events may take place that affect the performance of the devices being fabricated. That is, variations in the fabrication process steps result in device performance variations. Factors, such as feature critical dimensions, doping levels, particle contamination, film optical properties, film thickness, film uniformity, etc., all may potentially affect the end performance of the device. Various tools in the processing line are controlled in accordance with performance models to reduce processing variation. Commonly controlled tools include photolithography steppers, polishing tools, etching tools, and deposition tools, etc. Pre-processing and/or post-processing metrology data is supplied to process controllers for the tools. Operating recipe parameters, such as processing time, are calculated by the process controllers based on the performance model and the metrology data to attempt to achieve post-processing results as close to a target value as possible. Reducing variation in this manner leads to increased throughput, reduced cost, higher device performance, etc., all of which equate to increased profitability. Run-to-run control in semiconductor manufacturing is a type of batch control, where a batch may be as small as one wafer or as large as several lots of wafers. The standard output of a run-to-run controller is a process recipe. This recipe defines the set points for “low-level” controllers built into the processing tool. In this way, the run-to-run controller supervises the tool controller by specifying required values for process variables such as temperature, pressure, flow, and process time. The tool controller initiates the activities necessary to maintain these variables at the requested values. A typical run-to-run control setup includes a feedback loop where adjustments are made to the recipe parameters based on batch properties measured after processing. Typically, the job of the run-to-run controller is to ensure that each batch hits its inline target values. Inline targets refer to measurements that are taken while the wafers have only completed some of their processing steps. The inline targets are designed to provide guidelines for the functional parts at the end of the manufacturing line. Because the process states and other variables in the manufacturing processes can change over time, a successful controller must adapt to changing process conditions. At the foundation of such an adaptive controller are system identification techniques that aim to determine a model with the same input-output characteristics and possibly the same natural model structure as the physical system under study. In many practical applications, it is not feasible to obtain an exact model form for the process under study. Thus, online system identification often takes the form of a parameter estimation problem. In this formulation, a form for the model is predetermined, and the model parameters are updated recursively from process data. Changing process conditions can be seen as a change in the estimated model parameters over time. To achieve adequate performance in an uncertain environment, the control system should react quickly to process changes. Adaptive control techniques are a class of control schemes where the controller automatically adjusts its model parameters and tunes to account for observed changes in the process itself. These techniques often rely on online model parameter estimation, and the controller settings are continually adjusted to match the current system model derived from the measurements. Online system identification techniques are active as the process under study is running. They use process measurements and recursively update a system model of predetermined form. The estimator observes the system and adjusts the model parameters within the chosen model structure. In general, the estimator does not have a complete set of data with which to work. It only has access to the measurements that have already been made. A common exponentially weighted moving average (EWMA) filtering technique can be used in recursive parameter estimation. Here, a new parameter estimate is obtained by using a weighted combination of a parameter estimate based on the current measurement and the current parameter estimate as shown:{tilde over (x)}k+1=λxk+(1−λ){tilde over (x)}k, (1) where x is the measured value, {tilde over (x)} is the estimate, and λ is the exponential weighting factor. While the EWMA filtering technique is generally effective, it may not be particularly effective in estimating the true process state because of the presence of drifting disturbances and non-linear, changing slope. The EWMA filtering technique is slow to react to a fast drifting process in order to filter white noise (for example, when λ<0.5). Aside from the EWMA filtering techniques, Kalman filters can also be used in recursive parameter estimation. While Kalman filters are generally useful in drifting processes, they are not generally effective when non-white noise is present (e.g., a change in the slope of the drift). The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above. In one embodiment of the present invention, a method is provided for applying a self-adaptive filter to a drifting process. The method comprises processing a workpiece, measuring an output characteristic of the processed workpiece and modifying a previous estimated process state based at least on the measured output characteristic. The method further comprises estimating a next process state based at least on the modified previous estimated process state. In another embodiment of the present invention, an apparatus is provided for applying a self-adaptive filter to a drifting process. The apparatus comprises an interface communicatively coupled to a control unit. The interface is adapted to receive an output characteristic of a processed workpiece. The control unit is adapted to modify a previous estimated process state based at least on the received output characteristic and estimate a next process state based at least on the modified previous estimated process state. In a further embodiment of the present invention, an article comprising one or more machine-readable storage media containing instructions is provided for applying a self-adaptive filter to a drifting process. The one or more instructions, when executed, enable the processor to receive a measured output characteristic of a processed workpiece, modify a previous estimated process state based at least on the received output characteristic and estimate a next process state based at least on the modified previous estimated process state. In a further embodiment of the present invention, a system is provided for applying a self-adaptive filter to a drifting process. The system comprises a processing tool and a controller. The processing tool is adapted to process a workpiece. The controller is adapted to receive a measured output characteristic associated with the processed workpiece, modify a previous estimated process state of the processing tool based at least on the measured output characteristic and estimate a next process state of the processing tool based at least on the modified previous estimated process state. While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. Turning now to the drawings, and specifically referring to FIG. 1, a block diagram of a system 100 is illustrated, in accordance with one embodiment of the present invention. The system 100, in the illustrated embodiment, includes at least one process operation 102 for implementing an industrial process, such as a semiconductor fabrication process, a photographic process, a chemical process, or any other process in which the process state(s) or process output may drift with time. In the system 100, the process operation 102 may be performed using one or more processing tools 105. Generally, the particular type of process operation 102 that is performed, and the type of processing tool(s) 105 employed in that process operation 102, depends on the particular implementation. For example, in the context of a chemical industrial process, the process operation 102 may include processing a polymer. In the context of a photographic process, the process operation 102 may, for example, include processing a film. For illustrative purposes, the process operation 102 depicted in FIG. 1 is at least a portion of a semiconductor fabrication process, which, for example, may be part of an overall semiconductor process flow. Examples of the process operation 102 may be an etch process, deposition process, chemical mechanical planarization (CMP), and the like. The processing tool 105, in the illustrated embodiment, may take the form of any semiconductor fabrication equipment used to produce a processed workpiece, such as a silicon wafer. The semiconductor process may be utilized to produce a variety of integrated circuit products including, but not limited to, microprocessors, memory devices, digital signal processors, application specific integrated circuits (ASICs), or other similar devices. An exemplary processing tool 105 may include an exposure tool, an etch tool, a deposition tool, a polishing tool, a rapid thermal anneal processing tool, a test-equipment tool, an ion implant tool, a packaging tool and the like. In the system 100 of FIG. 1, the processing tool 105 has an associated equipment interface 110, and a metrology tool 112 has an associated equipment interface 113, for interfacing with an Advanced Process Control (APC) framework 120. In the illustrated embodiment, the metrology tool 112 measures aspects of the workpieces (e.g. wafers) 106 that are processed in the process operation 102 to provide processed workpieces 107. The metrology tool 112, in one embodiment, may be capable of measuring aspects of the workpieces off-line, in-line, in Situ or a combination thereof. The manufacturing system 100 may include a manufacturing execution system (MES) 115 that is coupled to the APC framework 120. The manufacturing execution system 115 may, for example, determine the processes that are to be performed by the processing tool 105, when these processes are to be performed, how these processes are to be performed, etc. In the illustrated embodiment, the manufacturing execution system 115 manages and controls the overall system through the APC framework 120. An exemplary APC framework 120 that may be suitable for use in the manufacturing system 100 may be implemented using the Catalyst system offered by KLA-Tencor, Inc. The Catalyst system uses Semiconductor Equipment and Materials International (SEMI) Computer Integrated Manufacturing (CIM) Framework compliant system technologies and is based on the Advanced Process Control (APC) Framework. CIM (SEMI E81-0699—Provisional Specification for CIM Framework Domain Architecture) and APC (SEMI E93-0999—Provisional Specification for CIM Framework Advanced Process Control Component) specifications are publicly available from SEMI, which is headquartered in Mountain View, Calif. The APC framework 120 includes a process controller 155 that, through a feedback or feedforward process, aids the processing tool 105 towards performing a desired process to thereby achieve a desired result. The process controller 155 in the illustrated embodiment includes a control unit 156, a storage unit 157, and a process model 158 that is storable in the storage unit 157. The process controller 155, based at least on an input from an estimator module 180, uses the process model 158 to determine the next control move for the processing tool 105. The particular control actions taken by the process controller 155 depend on the particular processes performed by the processing tool 105, and the output from the estimator module 180. The process model 158 may be developed empirically using commonly known linear or non-linear techniques. The process model 158 may be a relatively simple equation-based model (e.g., linear, exponential, weighted average, etc.) or a more complex model, such as a neural network model, principal component analysis (PCA) model, partial least squares projection/latent structures (PLS) model, or the like. The specific implementation of the process model 158 may vary depending on the modeling techniques selected and the process being controlled. The process controller 155, in one embodiment, maintains incoming “state” information associated with the process operation 102, where the “state” information may be based at least in part on the characteristics (i.e., wafer state data) of the wafer selected for gathering metrology data and/or state information known about the controlled processing tool 105 (i.e., tool state data). In the illustrated embodiment, the process controller 155 is computer programmed with software to implement the functions described. However, as will be appreciated by those of ordinary skill in the art, a hardware controller designed to implement the particular functions may also be used. Moreover, the functions performed by the process controller 155, as described herein, may be performed by multiple controller devices distributed throughout a system. Additionally, the process controller 155 may be a stand-alone controller, resident in the processing tool 105, or part of a system controlling operations in an integrated circuit manufacturing facility. The estimator module 180 estimates the next tool state of the processing tool 105 (or the next processing state) based on metrology data associated with a previously processed workpiece and a previous estimate state. The estimator module 180 receives data from the metrology tool 112 via the associated equipment interface 113. One embodiment of the estimator module 180 is described in FIG. 2, which is discussed in greater detail below. Referring again to FIG. 1, the estimator module 180 provides the estimated next tool state to a process controller 155, which then generates the next recipe or control move for the processing tool 105 based on the estimated next tool state. For example, in the context of an etching process, the estimator module 180 may estimate an etch rate of the processing tool 105, and then provide the estimated etch rate to the process controller 155, which then determines an etch time (i.e., recipe) that the processing tool 105 should etch the next workpiece (e.g., wafer). Unless specifically stated otherwise, or as is apparent from the discussion, terms such as “processing” or “computing” or “calculating” or “determining” or “displaying” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical, electronic quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system's memories or registers or other such information storage, transmission or display devices. It should be understood that the illustrated components shown in the block diagram of the system 100 in FIG. 1 are illustrative only, and that, in alternative embodiments, additional or fewer components may be utilized without deviating from the spirit or scope of the invention. For example, in one embodiment, the MES 115 may interface with the APC framework 120 through an associated equipment interface. Additionally, it should be noted that although various components, such as the equipment interface 110 of the system 100 of FIG. 1 are shown as stand-alone components, in alternative embodiments, such components may be integrated into the processing tool 105. Similarly, the estimator module 180 may be integrated into the process controller 155. Referring now to FIG. 2, a block diagram of the estimator module 180 is illustrated, in accordance with one embodiment of the present invention. The estimator module 180 includes a state estimate modifying module 210, a filter module 220, a limit module 230, and an EWMA module 240. The estimator module 180 of FIG. 2 is described in the context of the industrial system 100 of FIG. 1. Moreover, for the purposes of describing the estimator module 180 of FIG. 2, it is herein assumed that the process operation 102 of FIG. 1 is an etch process and that the processing tool 105 is an etch tool. The estimator module 180, in one embodiment, uses a state space model that describes the system dynamics of the etching process depicted by the process operation 102 of FIG. 1. For illustrative purposes, it is herein assumed that the dynamic behavior of the etch rates of the processing tool 105 can be described using a linear drift model shown in equations (2) and (3):x(k+1)=Ax(k)+v(k), (2)y(k)=Cx(k)+w(k), (3) where exemplary values of A and C may be A = [ 1 1 0 1 ] and C = [ 1 0 ] In the illustrated example, x ⁡ ( k ) = [ x ⁢ ⁢ 1 ⁢ ( k ) x ⁢ ⁢ 2 ⁢ ( k ) ] ,and thus comprises two states, an etch rate state x1(k) and a slope of the drift state x2(k). In the above equations, y(k) represents the output measurement (e.g., actual measured etch rate), v(k) represents the process noise term, and w(k) represents the measurement noise. The filter module 220 in the illustrated embodiment includes a Kalman filter for predicting the next state of the processing tool 105 or predicting the next processing state. In alternative embodiments, other filters or filtering techniques may be employed to predict the next process or tool states. Because the filter module 220 includes a Kalman filter, the general form of the steady-state filter module 220 is illustrated by equation (4):{circumflex over (x)}(k+1)=A{circumflex over (x)}(k)+L(y(k)−C{circumflex over (x)}(k)), (4) where L is the Kalman filter gain, and {circumflex over (x)}(k) is the estimate of x(k). As shown in equation (4), the next estimate process state, {circumflex over (x)}(k+1), is typically calculated based on the previous state estimate, {circumflex over (x)}(k). In accordance with one embodiment of the present invention, the previous state estimate, {circumflex over (x)}(k), is modified by the state estimate modifying module 210 before it is provided to the filter module 220 (i.e., the Kalman filter in this example). In particular, in one embodiment, the first element (etch rate), {circumflex over (x)}1(k), of the previous state estimate, {circumflex over (x)}(k), is modified in the manner set forth in equation (5):{circumflex over (x)}1(k)new=ζ{circumflex over (x)}(k)+(1−ζ)y(k), (5) where ζ is a weighting factor within an exemplary range of 0 and 1, y(k) is the process output (i.e., the actual measured etch rate in this example), and {circumflex over (x)}(k)new represents the modified first element of the previous state estimate. In an alternative embodiment, the state estimate modifying module 210 may modify the previous state estimate in the manner described by equation (6) below:{circumflex over (x)}1(k)new=ζ{circumflex over (x)}(k)+(1−ζ)(y(k)+y(k−1))/2, (6) where ζ is a weighting factor within an exemplary range of 0 and 1, and y(k) and y(k−1) are the two previous process outputs (i.e., in this example, the two previous actual measured etch rates). As can be seen, in equation (6), the new previous state, {circumflex over (x)}1(k)new, is calculated based on combining the previous estimate state, {circumflex over (x)}1(k), with an average of the two previous process outputs (i.e., y(k)+y(k−1)/2). In alternative embodiments, the previous estimate state, {circumflex over (x)}1 (k), can be modified in any other desirable manner based on the process output y(k) or previous outputs (i.e., y(k−1), y(k−2), and so forth). Once the previous estimate state, {circumflex over (x)}1(k), is modified using equations (5) or (6), the state estimate modifying module 210 provides the modified estimate state to the filter module 220, which then estimates the next process state, {circumflex over (x)}(k+1). The next process state, {circumflex over (x)}(k+1), may be calculated by substituting the modified previous state estimate, {circumflex over (x)}(k)new, for the previous state estimate, x(k), in equation (4) above. The result of this substitution is shown in equation (7) below:{circumflex over (x)}(k+1)=A{circumflex over (x)}(k)new+L(y(k)−C{circumflex over (x)}(k)new), (7) Thus, the filter module 220, estimates the next process state, {circumflex over (x)}(k+1), in the manner set forth in equation (7). The combination of the state estimate modifying module 210 and the filter module 220 forms an “adaptive” filter in the sense that when a process disturbance is introduced, the disturbance causes a large difference between {circumflex over (x)}(k) and y(k). This difference translates into {circumflex over (x)}(k)new diverging from {circumflex over (x)}(k), which changes the Kalman Gain, as is evident by inspection of equation (7) above. Thus, the larger the difference between {circumflex over (x)}(k) and y(k), the larger the change within the Kalman Gain. The estimator module 180 of FIG. 2 in the illustrated embodiment includes the limit module 230 and the EWMA module 240 that is coupled to the output of the limit module 230. The limit module 230, in one embodiment, may be utilized to control the change in the slope of the drift (i.e., the second state of {circumflex over (x)}(k)) that is provided by the Kalman filter. That is, in order to prevent sudden, large changes in the slope of the drift, which may adversely affect the estimation of the process states, the limit module 230 may limit the changes to some maximum preselected value. Limiting the amount of change in the slope of the drift to the preselected value may be needed in some circumstances because of the inherent delays associated with receiving the metrology data or errors associated with measurements of output characteristics. The EWMA module 240 of the estimator module 180 may be employed to reduce error variance in the estimated process states. Although in the illustrated embodiment of FIG. 2, the estimator module 180 includes modules 210, 220, 230, and 240, in an alternate embodiment the estimator module 180 may not necessarily employ all four modules, depending on the implementation. For example, in one embodiment, if the features of the limit module 230 and EWMA module 240 are not desired, the estimator module 180 may include the state estimate modifying module 210 and the filter module 220. As another example, if a reduction in estimate error variance provided by the EWMA module 240 is not desired, then the estimator module 180 may include modules 210, 220, and 230. Similarly, other combinations may be desirable, depending on the particular implementation. The modules 210, 220, 230, and 240 may be implemented in hardware, software, or a combination thereof. Referring now to FIG. 3, a flow diagram of a method that may be implemented in the manufacturing system 100 of FIG. 1 is illustrated, in accordance with one embodiment of the present invention. For ease of illustration, the method of FIG. 3 is described in the context of an etch process, although the method is not limited as such and may be applicable to any drifting process. The estimator module 180 estimates (at 308) a process state, which in the illustrated example is an etch rate. The etch rate, in one embodiment, is provided to the process controller 155, which determines a control move (e.g., etch time) for the processing tool 105. The processing tool 105 processes (at 310) a workpiece based on the estimated process state. In the context of an etch process, the processing tool 105 etches a wafer based on the recipe (or control move) that is generated based on the estimated etch rate. The metrology tool 112 (or an in-situ metrology tool) measures (at 312) one or more output characteristics of the workpiece processed (at 310) by the processing tool 105. In the context of an etch process, the metrology data may, for example, include the etch depth of the processed wafer. The metrology data is provided to and received by (at 315) the estimator module 180. The estimator module 180 modifies (at 320) the estimated process state (see block 308) based at least on the received output measurements. Because the estimated process state was calculated for the previously processed workpiece, it is hereinafter referred to as “the previous process state estimate.” In one embodiment, the previous process state estimate is modified in a manner set forth in equation (5) or (6), depending on the desired implementation. The modified “previous process estimate” is then provided to the filter module 220. The filter module 220 estimates (at 325) a next process state based on at least the modified estimated process state. In one embodiment, the filter module 220 estimates the next process state (at 325) in accordance with equation (7) set forth above. In one embodiment, the limit module 230 may be utilized to limit (at 330) the change in the second state of the next process state to a preselected threshold value. As noted above, the second state, in the illustrated example, corresponds to a drifting slope state. The preselected threshold value that is chosen depends on the particular implementation, and may be a range of values, in one embodiment. For example, in the context of an etch process, the preselected threshold value may be a range from −0.01 to −0.1 that defines the minimum and maximum change in the slope that is allowed. In one embodiment, the EWMA module 240 may be applied (at 335) to reduce error variance in the next process state determined by the filter module 220. That is, the EWMA module 240 may apply the conventional common exponentially weighted moving average filtering technique to further improve the process state estimation. While the method of FIG. 3 is described in the context of processing a single workpiece, it should be understood that the method is not limited as such. The method can be readily extended to a process in which a batch or a lot of workpieces are processed substantially simultaneously. FIGS. 4-6 illustrate exemplary graphs of an etch process in which one or more embodiments of the present invention are employed for process state estimation (i.e., etch rate estimation, in the instant example). In FIG. 4, the state estimate modifying module 210 and the filter module 220 of FIG. 2 are employed to estimate the etch rate. In FIG. 5, the state estimate modifying module 210, the filter module 220, as well as the limit module 230 are employed to estimate the etch rate. In FIG. 6, all of the modules 210, 220, 230, and 240 of the estimator module 180 of FIG. 2 are employed to estimate the etch. Referring in particular to FIG. 4, a graph of an etch process is illustrated in which the state estimate modifying module 210 and the filter module 220 are employed to estimate the etch rate. The x-axis represents time, and the y-axis represents the etch rate. In the illustrated example of FIG. 4, graph 410 represents the actual (or real) etch rate of the etch process, graph 420 represents the etch rate estimation by the conventional EWMA filtering technique, graph 430 represents the etch rate estimation by a conventional Kalman filter, and graph 440 represents the etch rate estimation by the estimator module 180 of the present invention in which modules 210 and 220 are employed. The general path of graph 410 (the actual etch rate) illustrates that the etch rate generally drifts with time, and along the way, several disturbances are encountered (as evidenced by the presence of several peaks and valleys). As can been seen with reference to FIG. 4, when the process drifts fast (see time t1 where the slope of the line is relatively steep or large), the EWMA estimation graph 420 lags, and thus is not quick to follow the actual drift. With respect to the Kalman estimation graph 430, it is not very effective to the drift slope changes (see time t2). As can be seen, graph 440, which represents the state estimation of one embodiment of the present invention, is more adept to a fast drifting process as well as to a drift slope change. Referring now to FIG. 5, a graph of an etch process is illustrated in which the state estimate modifying module 210, the filter module 220, and the limit module 230 of FIG. 2 are employed to estimate the etch rate. The x-axis represents time, and the y-axis represents the etch rate. In the illustrated example of FIG. 5, graph 510 represents the actual (or real) etch rate of the etch process, graph 520 represents the etch rate estimation by the conventional EWMA filtering technique, graph 530 represents the etch rate estimation by a conventional Kalman filter, and graph 540 represents the etch rate estimation by the estimator module 180 of the present invention in which modules 210, 220, and 230 are employed. As can been seen with reference to FIG. 5, at time t1, graph 540 of the estimator module 180 is substantially closer to the actual etch rate (i.e., graph 510) than the EWMA estimation graph 520. This is because the limit module 230 of the estimator module 180 is employed in this example to reduce the amount of change that is allowed in the slope of the drift. Similarly, at time t2, graph 540 tracks the actual etch rate 510 closer than the Kalman graph 530 because of the limits placed on the drifting slope. Referring now to FIG. 6, a graph of an etch process is illustrated in which the state estimate modifying module 210, the filter module 220, the limit module 230, and the EWMA module 240 of FIG. 2 are employed to estimate the etch rate. The x-axis represents time, and the y-axis represents the etch rate. In the illustrated example of FIG. 6, graph 610 represents the actual (or real) etch rate of the etch process, graph 620 represents the etch rate estimation by the conventional EWMA filtering technique, graph 630 represents the etch rate estimation by a conventional Kalman filter, and graph 640 represents the etch rate estimation by the estimator module 180 of the present invention in which modules 210, 220, 230 and 240 are employed. As can been seen with reference to FIG. 6, the estimation of the etch rate by the estimator module 180, as indicated by graph 640, is improved around the region identified by reference number 650. This improvement is due in part to the application of the EWMA module 240 (see FIG. 2) to the output of the limit module 230. Referring now to FIG. 7, an exemplary simulation graph that compares the performance of the EWMA, the Kalman filter, and the estimator module 180 is illustrated, in accordance with one embodiment of the present invention. In particular, FIG. 7 illustrates a reference output graph 710, a state estimation graph 720 generated based on applying an EWMA filtering technique, a state estimation graph 730 generated based on applying a Kalman filter, and a state estimation graph 740 generated based on applying the estimator module 180 employing the state estimate modifying module 210 and the filter module 220 of FIG. 2. As can been seen in FIG. 7, the estimator module 180 of the present invention, as compared to the Kalman filter and EWMA, is more responsive to drift and step disturbances. Moreover, the graph shows that the steady state error from the estimator module 180 is smaller than those from the EWMA or Kalman filter. One or more embodiments of the present invention improve the estimation of process states. The described embodiments are useful in estimating process states in a variety of processes that may drift with time. Because of their self-adaptive nature, the state estimation techniques described herein are effective in reacting to large step and drifting disturbances, while providing unbiased estimates with smaller mean square error. The various system layers, routines, or modules may be executable by the control unit 156 (see FIG. 1). As utilized herein, the term “control unit” may include a microprocessor, a microcontroller, a digital signal processor, a processor card (including one or more microprocessors or controllers), or other control or computing devices. The storage unit 157 (see FIG. 1) referred to in this discussion may include one or more machine-readable storage media for storing data and instructions. The storage media may include different forms of memory including semiconductor memory devices such as dynamic or static random access memories (DRAMs or SRAMs), erasable and programmable read-only memories (EPROMs), electrically erasable and programmable read-only memories (EEPROMs) and flash memories; magnetic disks such as fixed, floppy, removable disks; other magnetic media including tape; and optical media such as compact disks (CDs) or digital video disks (DVDs). Instructions that make up the various software layers, routines, or modules in the various systems may be stored in respective storage devices. The instructions when executed by a respective control unit cause the corresponding system to perform programmed acts. The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.
	summary
048620050	claims	1. An apparatus for detecting radiation in hand-holdable objects, comprising: a. a radiation detector assembly including a radiation detector means having a top side that is sensitive to both beta and gamma radiation throughout its area, and a platform means disposed over the top side of the detector means for both supporting the hand-holdable object being examined and for uniformly spacing the object from the detector means, and b. a shielding cabinet for containing the radiation detector assembly and shielding the detector means from background radiation, said cabinet having an access opening for allowing an operator to deposit and withdraw an object onto and the off of the platform means. a. a radiation detector assembly including a first radiation detector means having a top side that is sensitive to both beta and gamma radiation throughout substantially all of its area, wherein the area of the top side includes a plurality of mutually overlapping zones, each of which is independently sensitive to radioactivity for both increasing the sensitivity of the detector means as a whole over background radiation and for facilitating locating which particular area of an object is contaminated with radioactive particles, and a platform means including a section of sheet material having a plurality of openings disposed over the top side of the detector means, wherein the area of the openings is at least 70 percent of the area of the sheet material as a whole to allow said sheet material to substantially conduct beta radiation, and b. a shielding cabinet for containing the radiation detector assembly and shielding the detector means from background radiation, said shielding cabinet having an access opening for allowing an operator to deposit and withdraw an object onto and off of the platform means. 2. The apparatus defined in claim 1, wherein the detector means includes a plurality of mutually adjacent zones, each of which is independently sensitive to radioactivity for indicating which portions of a particular object are contaminated with radioactive particles. 3. The apparatus defined in claim 2, wherein said detector means is a gas-flow proportional detector having a single conductive housing for forming one electrode of one charge, and a plurality of parallel electrode wires for forming multiple electrodes of an opposite charge. 4. The apparatus defined in claim 3, wherein said radiation detector assembly includes a source of pressurized counting gas fluidly connected to said gas-flow proportional detector for constantly replenishing the counting gas within the detector. 5. The apparatus defined in claim 4, wherein the radiation detector assembly includes a spare gas-flow proportional detector that is likewise fluidly connected to said source of pressurized counting gas so that said spare detector will be substantially purged and ready for operation in the event of a malfunction of said original detector. 6. The apparatus defined in claim 1, wherein said platform means includes a perforated sheet of metal wherein the area of the openings in the sheet takes up at least 60 percent of the area of the sheet to render the sheet substantially conductive to beta radiation. 7. The apparatus defined in claim 1, wherein the platform means includes a removable protective film for preventing lint and debris from entering the detector means. 8. The apparatus defined in claim 7, wherein said film is a film of flexible plastic material. 9. The apparatus defined in claim 8, wherein the density thickness of said film is between 0.2 and 0.8 mg/cm.sup.2. 10. The apparatus defined in claim 6, wherein said platform means further includes a support grid for supporting both a film of aluminized flexible plastic material and said perforated sheet of metal. 11. The apparatus defined in claim 1, wherein said shielding cabinet includes a sheet of shielding material supporting the detector means, for shielding the detector means from background radiation and for reflecting a portion of the gamma radiation that the top side of the detector means is exposed to in order to increase the gamma radiation sensitivity of the detector means. 12. The apparatus defined in claim 1, wherein said shielding cabinet includes at least one cabinet door for providing additional access to the top side of the detector means. 13. The apparatus defined in claim 1, wherein said shielding cabinet includes cabinet doors on opposing sides to allow objects longer than the width of the shielding cabinet to be passed over the top side of the detector means. 14. The apparatus defined in claim 1, wherein at least some of the walls of the shielding cabinet include a pocket means for receiving a sheet of shielding material. 15. The apparatus defined in claim 14, further including an end cap means for opening and closing said pocket means. 16. The apparatus defined in claim 15, wherein said pocket means is of sufficient size to receive more than one sheet of shielding material so that the amount of radiation afforded by the walls of the shielding cabinet may be varied. 17. The apparatus defined in claim 1, further including a support cabinet for supporting said shielding cabinet. 18. The apparatus defined in claim 1, further comprising a foot-switch means for actuating the detector means. 19. The apparatus defined in claim 1, further comprising a support cabinet means for both supporting the shielding cabinet and for housing radiation detector circuitry that is electrically connected to the radiation detector means. 20. The apparatus defined in claim 12, wherein said cabinet door forms a shelf leading into the top side of the detector means when opened. 21. An apparatus for detecting radiation in hand-holdable objects, comprising: 22. The apparatus defined in claim 21, wherein said shielding cabinet includes doors on opposing sides of the cabinet and door support assemblies for pivotally connecting each of said doors along one of its sides to the cabinet, and wherein each door support assembly substantially aligns the respective door with the top side of the radiation detector means when said doors are opened so that said doors may be used as shelves. 23. The apparatus defined in claim 22, wherein said door support assemblies each include an elongated link member that is slidably engaged with a rivet. 24. The apparatus defined in claim 21, wherein said detector means is a gas-flow proportional detector having a single conductive housing for forming one electrode of one charge, and a plurality of parallel electrode wires for forming multiple electrodes of an opposite charge. 25. The apparatus defined in claim 21, wherein the platform means includes a screen member and a removable protective film for preventing lint and debris from entering the detector means. 26. The apparatus defined in claim 25, wherein said film is a film of flexible plastic material. 27. The apparatus defined in claim 26, wherein the density thickness of said film is between 0.2 and 0.8 mg/cm.sup.2. 28. The apparatus defined in claim 26, wherein said platform means further includes a support grid for supporting both a film of aluminized flexible plastic material as well as said screen member. 29. The apparatus defined in claim 21, wherein said shielding cabinet includes a sheet of shielding material for supporting the detector means, shielding the detector means from background radiation and for reflecting a portion of the gamma radiation that the top side of the detector means is exposed to in order to increase the gamma radiation sensitivity of the detector means. 30. The apparatus defined in claim 21, wherein at least some of the walls of the shielding cabinet include a pocket means for removably mounting a sheet of shielding material. 31. The apparatus defined in claim 30, further including an end cap means for opening and closing said pocket means. 32. The apparatus defined in claim 31, wherein said pocket means is of sufficient size to receive more than one sheet of shielding material so that the amount of radiation afforded by the walls of the shielding cabinet may be varied. 33. The apparatus defined in claim 31, further comprising a foot-switch means for actuating the detector means. 34. The apparatus defined in claim 21, further comprising a support cabinet means for both supporting the shielding cabinet and for housing a radiation detector circuitry that is electrically connected to the radiation detector means. 35. The apparatus defined in claim 21, wherein the access opening is orthogonally oriented with respect to the radiation sensitive, top most side of the detector means to minimize the exposure of the detector means to background radiation. 36. The apparatus defined in claim 35, wherein the access opening is offset with respect to the detector means to prevent direct rays of background radiation from striking the detector means. 37. The apparatus defined in claim 21, further including a support table means for supporting a second detector means over the first detector means, and for defining a space between said first and second detectors that elongated objects may be conducted through.
	abstract	The parallel radiation (12) emanating from a sample 4 in a known apparatus for X-ray analysis (for example, for diffraction) is analyzed according to wavelength and focused in a focus 20 by a parabolic multilayer mirror 14. A collimator 28 is positioned around said focus. The resolution of the apparatus can be enhanced by making the angular passage width of the collimator smaller than the maximum range of its reflection angle xcex1max. In accordance with the invention the resolution of the apparatus will be better defined and hence enhanced by implementing the exit collimator 28 in such a way that the angular value for the passage width from every reflecting point A or B of the mirror surface is substantially independent of the position of the reflecting points. Preferably, the exit collimator 28 is implemented in the form of two mutually parallel knife edges which are situated at different distances from the reflecting points of the multilayer mirror.
	summary
043084605	description	DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings, there is shown a fuel storage system 50 which includes a circular base plate 55 having opposed upper surface 56 and lower surface 57. A circular groove 58 is in the upper surface 56 spaced inwardly from the edge of the circular plate 55. An O-ring gasket 59 is positioned in the groove 58 and may be made of any suitable material, such as neoprene. Depending from the lower surface 57 of the circular base plate 55 is a pedestal 60 which is cylindrical and has a beveled end 61 and a central aperture 62 extending the length thereof, the pedestal extending perpendicularly from the circular base plate 55. A cotter pin hole 64 extends transversely of the pedestal 60 near the beveled end 61 thereof and is provided with a cotter pin 65. A cover 70 has a cylindrical body portion 71 closed by a flat top portion 72 having a circular aperture 73 therein. The aperture 73 is closed by a filter 75 which may be porous stainless steel having openings about 5 microns in diameter. The cover 70 and more particularly the cylindrical body portion 71 terminates in an annular flange 77 having the same radial dimension as the circular plate 55, the annular flange being dimensioned to overlie the circular plate 55 and more particularly to be in registry with the circular groove 58 and the O-ring gasket 59 positioned therein. The cover 70 further includes a handle 80 pivotally mounted as at 81 to the cover. The cover 70 and the circular plate 55 are maintained in sealed relation by means of a V-clamp 85 which provides quick disconnecting of the cover 70 and the base plate 55 when access to the radioactive material stored in a nuclear material fuel box 115 positioned in the storage area 110 defined by the circular base plate 55 and the cover 70. The beveled end 61 of the pedestal 60 prevents balancing of the storage system 50 on the pedestal 60 which would result in an unstable condition. The beveled end 61 also facilitates introduction of the pedestal onto a stand 90 which includes a flat base plate 91 and perpendicularly upstanding rod 92, the rod being dimensioned to receive the pedestal 60 thereover. The stand 90 is used in the laboratory when the nuclear material present in the fuel box 115 is to be removed for experimental purposes or for inventory. When the system 50 is used for out of the way storage purposes, a wall mount 100 is provided. The wall mount 100 includes two vertically spaced apart collars 101 each attached to an arm 102 connected to a wall 105. Each of the collars 101 has a vertically extending aperture 103 therein aligned and dimensioned to receive the pedestal 60 of the storage system 50 therethrough. In this manner, individual ones of the storage systems 50 may be stored at preselected positions along the wall 105 thereby to prevent accidental assembly of a critical mass. In a constructional example of the present invention, the nuclear fuel box 115 is dimensioned to carry plutonium plates varying in sizes from 2".times.2".times.2" to 2".times.2".times.8" or enriched uranium 235 plates varying in size from 2".times.2".times.2" to 2".times.3". The nuclear fuel box 115 may be made of any suitable shielding material such as lead. The object is to make the fuel storage system 50 as small as possiible for weight purposes to facilitate easy transport by operating personnel. The preferred construction material is, although not necessarily, cast aluminum with the base plate 55 being 3/4 inch thick and 4 15/16 inches in diameter. Similarly, the cover 70 is cast aluminum of about 1/8 inch thickness with the flange 77 being thicker. The cover 70 is about 63/4 inches high and has a diameter of 4 15/16 inch to match that of the base plate 55. The pedestal 60 is about 11/2 inches in diameter and approximately 21/2 inches long. The stand 90 as well as the wall mount 100 must be dimensioned to accommodate the specific fuel storage system 50, and the sizes may vary from the specific example given. Another advantage of the present invention is that when nuclear material is stored in the storage system 50 and mounted on a wall mount 100 it is substantially tornado or earthquake proof, the cotter pin 65 serving to lock the system 50 in place on the wall mount 100. The filter 75 is preferably made of a porous stainless steel metal with the pores being about 5 microns in diameter, thereby allowing gases to escape but preventing radioactive particles from contaminating the atmosphere. In general, only one V-clamp 85 is necessary to maintain the cover 70 in sealed relation with the base plate 55, but more may be used if deemed necessary. The V-clamp 85 is of the type that is maintained in the clamped position by a threaded member (not shown) but various alternatives well known to those skilled in the art may be used. It will be seen that there has been provided a fuel storage system which is light weight and easily accessible. The system is not designed nor is it capable of functioning as a transport container but is specifically designed for use in a laboratory where containment is necessary yet relatively quick and easy access to the nuclear material is required. When mounted on a wall 100, the fuel storage system 50 of the present invention is substantially earthquake and tornado proof and ensures against inadvertent assembly of any critical masses. While there has been illustrated what at present is considered to be the preferred embodiment of the present invention, it will be understood that various modifications and alterations may be made therein without departing from the scope of the present invention, which is intended to be covered in the claims appended thereto.
	claims	1. A facility comprising:at least one shielding barrier forming at least one wall of a room, wherein a thickness of the at least one shielding barrier is 0.5 meter to 6 meters, wherein the shielding barrier comprises a radiation shielding fill material comprising at least fifty percent by weight of an element having an atomic number from 12 to 83. 2. The facility of claim 1, wherein the at least one shielding barrier provides shielding for a person, a radio sensitive object, or an electronic device against radiation radiating from opposite the at least one wall from the person or the electronic device. 3. The facility of claim 1, wherein the at least one shielding barrier comprises a plurality of walls and provides protection against the radiation for a person located outside the room, or provides protection for a radio sensitive object or an electronic device located outside the room. 4. The facility of claim 1, wherein the at least one shielding barrier comprises a plurality of walls and provides protection against the radiation for a person located inside the room or provides protection for an electronic device located inside the room. 5. The facility of claim 1, wherein the radiation shielding fill material comprises at least fifty percent by weight of at least one of magnetite or hematite based on the total weight of the radiation shielding fill material. 6. The facility of claim 1, wherein the at least one wall comprises a plurality of removable panels that are combinable to form the at least one wall. 7. The facility of claim 6, wherein the plurality of removable panels are constructed to be assembled together by aligning one panel with another panel. 8. The facility of claim 6, wherein the plurality of removable panels are constructed to be assembled together by aligning one panel of the plurality of removable panels above or below another panel of the plurality of removable panels. 9. The facility of claim 6, wherein the plurality of removable panels are constructed to be assembled together by aligning one of the plurality of removable panels on either side with another panel of the plurality of removable panels. 10. The facility of claim 6, wherein the radiation shielding fill material is removable or replaceable. 11. The facility of claim 6, wherein the plurality of removable panels are transportable to a construction site for assembling at the construction site to create the at least one wall. 12. The facility of claim 6, wherein the plurality of removable panels can be recombined to change: a shape of a shielded void space, change a shape of a shielded room, to increase shielding or to decrease shielding. 13. The facility of claim 6, wherein the radiation shielding fill material is positioned between at least two of the plurality of removable panels. 14. The facility of claim 6, wherein the plurality of removable panels comprise a shippable module having conduit or ducts placed therein prior to shipping to a construction site. 15. The facility of claim 6, wherein at least one of the plurality of removable panels can be removed while other of the plurality of removable panels maintain shielding or maintain structure for the facility. 16. A method of providing a facility comprising:providing a plurality of shielding modules to form at least one compartment of at least one shielding barrier, wherein a thickness of the at least one shielding barrier is 0.5 meter to 6 meters; andproviding radiation shielding fill material comprising at least fifty percent by weight of an element having an atomic number from 12 to 83 for filling the at least one compartment. 17. The method of claim 16, wherein the at least one shielding barrier provides shielding for a person, a radio sensitive object or an electronic device against radiation radiating from a source opposite the at least one shielding barrier from the person or the electronic device. 18. The method of claim 16, wherein the at least one shielding barrier comprises a plurality of walls forming a room and the at least one shielding barrier provides protection against radiation originating inside of the room for a person located outside the room, or provides protection for a radio sensitive object or an electronic device located outside the room. 19. The method of claim 16, wherein the at least one shielding barrier comprises a plurality of walls forming a room and the at least one shielding barrier provides protection against the radiation originating outside of the room for a person located inside the room, or provides protection for a radio sensitive object or an electronic device located inside the room. 20. The method of claim 16, wherein the radiation shielding fill material comprises at least fifty percent by weight of at least one of magnetite or hematite based on the total weight of the radiation shielding fill material. 21. The method of claim 16, wherein the plurality of shielding modules each have at least one side comprising a metal wall. 22. The method of claim 16, wherein the plurality of shielding modules are a plurality of prefabricated modules. 23. The method of claim 22, further comprising shipping the plurality of prefabricated modules to a construction site. 24. The method of claim 22, further comprising assembling together the plurality of prefabricated modules at a construction site by aligning one of the plurality of prefabricated modules with another of the plurality of prefabricated modules. 25. The method of claim 22, wherein the radiation shielding fill material is positioned between at least two of the plurality of prefabricated modules. 26. The method of claim 16, wherein the at least one shielding barrier comprise a plurality of shielding barriers forming a room within a room. 27. The method of claim 16, wherein the radiation shielding fill material is removable, or the radiation shielding fill material is replaceable with another radiation shielding fill material. 28. A method for providing a facility comprising:assembling a plurality of prefabricated modules to create a shielding barrier; andfilling at least one compartment of the shielding barrier with a radiation shielding fill material, wherein a thickness of the at least one shielding barrier is 0.5 meter to 6 meters and the radiation shielding fill material comprises at least fifty percent by weight of an element having an atomic number from 12 to 83. 29. The method of claim 28, wherein the at least one compartment comprises a plurality of compartments including a first compartment and a second compartment. 30. The method of claim 29, wherein in the filling step, the first compartment is filled with the radiation shielding fill material and the second compartment is not filled with the radiation shielding fill material. 31. The method of claim 29, wherein in the filling step, the radiation shielding fill material of the first compartment is different from the radiation shielding fill material of the second compartment. 32. The method of claim 28, wherein the radiation shielding fill material is replaceable with a different radiation shielding fill material having different shielding properties. 33. The method of claim 28, wherein the radiation shielding fill material is removable from the at least one compartment.
	summary
050733338	summary	TECHNICAL FIELD The present invention relates to a method by which radioactive coatings or deposits on the walls of the primary heating system in nuclear reactors of the pressurized water type, the boiler reactor type with hydrogen dosage, etc., can be removed. More specifically, the invention relates to the decontamination of acid insoluble or in acid sparingly soluble corrosion or oxidation products from such primary system surfaces. In this respect the invention is a development of the technique which comprises contacting the contaminated surfaces with an oxidation agent in an acid solution and dissolving those corrosion products which have been made acid soluble by said oxidation. BACKGROUND OF THE INVENTION The background of and an elucidation of the problems in connection with corrosion products derived from the primary heating system of nuclear reactors are closely described in U.S. Pat. No. 4,704,235 (corresponds to Swedish Publication No. 451,915 and U.S. Pat. No. 4,704,235. Said patent specification also discloses a method by means of which many of the problems within this area are eliminated or at least substantially reduced. Said method is especially adapted for use in operating and maintaining working plants of the pressurized water reactor type. The present invention represents a development of the method referred to, where the invention has been shown to give an improved decontamination effect as well as the possibility of obtaining a final product that is less environmentally harmful or more suited to be deposited than the final product disclosed in the above-mentioned Swedish patent specification. In this context, it has turned out that the invention is such effective and advantageous that it is especially well suited for the decontamination of reactors in connection with an ultimate demolition thereof or a scrapping of spent components thereof. A practically useful and accepted method of last-mentioned type is definitely desired in Sweden today. Thus, the Swedish nuclear plants comprise reactors which were started between 1972 and 1985. A natural consequence thereof is that the requirements for maintenance and repairs of system components will continue to increase. Eventually some of these components have to be replaced. Replacements have already started of a number of large components, such as preheaters, moisture separators, etc., at some of those plants which were started first. The replaced components can either be transferred to SFR for an ultimate deposit, optionally after some intermediate deposit in the plants, or be conditioned for example to make possible a free-classification/recycling of material. If the latter alternative is chosen, which is the preferred one if one wants to minimize the total volume of waste to be sent to the ultimate deposit, there will for instance be a great demand for decontamination methods giving high decontamination factors (DF). In addition thereto it must be possible to take care of the secondary waste obtained in an acceptable way. It has been found that the method according to the invention gives a solution to said problem. In this context it can be added that today a number of "hard" decontamination methods are available but that generally these methods are characterized by several treatment steps, which for instance means that large amounts of chemicals have to be taken care of. Furthermore, many of these chemicals are difficult to treat. The method according to U.S. Pat. No. 4,704,235 is based on an exposure of the contaminated surfaces or oxides to an oxidation agent in an acid solution, which oxidation agent is a combination of Ce.sup.4+ ions, ozone and chromic acid, nitric acid being specifically mentioned as the most effective and suitable acid. The present invention is based on principally the same oxidation components, i.e. Ce.sup.4+, ozone and chromic acid, the oxidation, however, being performed under different acid conditions than according to the prior art, which has been found to give essential advantages for many purposes. U.S. Pat. No. 4,657,596 discloses the use of a decontamination agent which may contain a perhalogen acid, but said decontamination agent does not comprise all components which are required according to the present invention to obtain a synergistic effect. Furthermore, U.S. Pat. No. 4,657,596 does not disclose or even suggest that a perhalogen acid might be better than any of the other acids mentioned. Rather, the best decontaminating factors are obtained by means of an agent based on sulphuric acid. GENERAL DISCLOSURE OF THE INVENTION More specifically, the present invention relates to a method of decontaminating radio nuclide-contaminated corrosion products, which are sparingly soluble or insoluble in acids, from primary system surfaces in nuclear reactors of the pressurized water type and the boiler type with hydrogen dosage or similar, where the contaminated surfaces are contacted with an oxidation agent in an acid solution so as to obtain an oxidation in the presence of Ce.sup.4+ ions, ozone and chromic acid, and the corrosion products which have been made acid soluble through said oxidation are dissolved. The novel feature of the invention is that it has surprisingly been found that essential improvements relative to the prior art can be obtained if said oxidation with Ce.sup.4+ ions, ozone and chromic acid is performed in the presence of perhalogen acid at relatively low pH values. More specifically, the method according to the invention is characterized by performing the oxidation with Ce.sup.4+ ions, ozone and chromic acid with such concentrations thereof which are required for the decontamination, in the presence of perhalogen acid at a pH below 3. Thus, it has been found that essentially higher decontamination factors are obtained by means of perhalogen acid as the acid to be used in the oxidation, the use of perhalogen acid also representing the essential advantage that after the finalized treatment said acid can be reduced in a manner known per se to any halogenide-containing compound, which is considerably more suitable for deposition than an environmentally non-favourable nitrate or any environmentally non-favourable nitrogen compound according to the prior art. In this context, it has been found that the method according to the invention is such effective that it is especially well suited for the decontamination of reactors for a complete demolition or dismantling thereof or for a scrapping of components from said reactors. The measure that the oxidation reaction according to the present invention is performed "in the presence of perhalogen acid" should be interpreted in a wide sense, i.e. it is not absolutely necessary to add perhalogen acid initially as the acid medium, although this is generally the most suitable and preferred embodiment. Thus, said perhalogen acid can also be formed in situ in the reaction by starting from a halogen-containing acid, where the halogen is present in a lower valence state or stage than in perhalogen acid, the starting acid being oxidized by the present ozone up to perhalogen acid during the reaction. As perhalogen acid such as perchloric acid is preferably used, but the method could be performed also with perbromic acid or periodic acid, although the two last-mentioned acids are somewhat weaker as oxidizing agents than the preferred perchloric acid. Therefore, for convenience the invention will be discribed in connection with a use of perchloric acid, although it should be understood that corresponding considerations are applicable to perbromic and pariodic acid, respectively. As was mentioned above the oxidation is performed at relatively low pH values, viz. at a pH below 3, an especially preferable embodiment, however, being a performance of the method at a pH of at most 2 or below 2 or even more preferable at most 1 or below 1, especially within the pH range of 1-0.5. Generally this means that the oxidation is performed with perhalogen acid, preferably perchloric acid, having a molarity within the range of 0.01-8M, preferably within the range of 0.1-2M. As will be illustrated more below the claimed combination of oxidation agents in the specified perhalogen acid medium has been shown to give an unexpectedly good synergistic effect. This means that the amounts or concentrations used of the different components of the oxidation system are not primarily the characteristic features of the invention, but said concentrations can of course easily be determined by the skilled artisan in each case based on the decontamination effect desired or required. Generally, however, it can be mentioned that suitable concentrations are the following: Ce.sup.4+, i.e. calculated as cerium in the utilized salt, within the range of 0.01-50 g per liter of used aqueous solution; ozone within the range of 0.001-1 g/l and chromic acid in a contration of 0.001-50 g/l. Especially preferable concentrations according to the invention within the above-defined ranges are 0.5-10 g/l as concerns cerium, 0.001-0.05 g/l as concerns ozone and 0.005-0.2 g/l as concerns chromic acid. Otherwise, the components of the combined oxidation agent according to the invention can principally be chosen in accordance with the prior art, i.e. mainly in accordance with the disclosure of the above-mentioned Swedish patent specification. Thus, for instance for the cerium component it is not necessary to start from a Ce.sup.4+ salt, but one may well start from a Ce.sup.3+ salt, the Ce.sup.3+ ion automatically being oxidized up to a valence stage of 4 by the present ozone. As said cerium compound or cerium salt it is preferable to start directly with cerium perchlorate as perchloric acid is utilized as the acid medium, i.e. so as to avoid the incorporation of different ions into the system. In such a case cerium perchlorate is prepared in a manner known per se, which need not be described here. Similar considerations are applicable to perbromate and periodate. However, the method according to the invention is applicable to the use of any cerium salt that does not interfere with the reaction, another suitable example of a cerium salt being cerium nitrate. The only matter of importance is that the Ce.sup.4+ ion required for the oxidation is available. Thus, such cerium salts which give precipitations (for instance cerium sulphate) or gas evolution (for instance cerium chloride) and similar should be avoided. Also the chromic acid can be selected in accordance with those principles which are disclosed in the above-mentioned Swedish patent specification. However, it can be added that the primary feature of the invention is that chromic acid is present during the oxidation reaction per se. This does not necessarily mean that an external additional chromic acid is necessary, since the method is essentially merely intended for the decontamination of chromium-containing steel, which means that the requisite quantities or concentrations of chromic acid are automatically formed after some starting period of operation. It has also been shown that the present method gives a remarkably good effect as concerns the dissolution of chromium rich spinels of the type that it present in pressurized water reactors, etc. However, an external as well as initial addition of chromic acid is preferred according to the invention. Also concerning the ozone the previously known principles for the addition thereof are applicable, i.e. essentially those principles which are disclosed in the above-mentioned Swedish patent specification. According to a preferable embodiment of the invention this means that as the oxidation agent there is used an acid aqueous solution of the cerium compound and the chromic acid and ozone in a preferably saturated solution and in the dispersed form. However, according to another embodiment of the method according to the invention the oxidation agent can be utilized in the form of a two-phase ozone gas-aqueous mixture, where ozone in gaseous form has been dispersed in an acidic aqueous solution of cerium compound and chromic acid. It has been found that the method according to the invention is such effective that it is possible to perform in one single step the oxidation as well as the dissolution with the desired results, which means that this is also a preferable embodiment of the method. Another advantage of the method is that the desired results can be obtained when performing said method at such a low temperature as room temperature, which is of course very valuable. Thus, an especially preferable embodiment of the method according to the invention means that the decontamination is performed at room temperature or even lower, i.e. primarily at a temperature within the range of 20.degree.-30.degree. C., especially within the range of 20.degree.-25.degree. C. However, the method according to the invention is of course performable also at higher temperatures, although it may generally be suitable to work at a temperature below about 60.degree. C., since otherwise the decomposition of for instance ozone may become so vigorous that it counteracts the effect that is generally achieved by raising the temperature, i.e. the common effect that the reaction rate increases with increasing temperatures. As was mentioned above the method according to the invention is advantageous through the choice of perchloric acid also through the fact that after the finalized treatment said acid can be reduced in a manner known per se to a more environmentally favourable waste or deposit product than the previously specifically mentioned nitrate. Thus, a preferable embodiment of the method according to the invention means that the solution obtained after oxidation and dissolution is treated with a previously known reducing agent to reduce the perchloric acid to an environmentally favourable chloride salt. Such a chloride salt may for instance be sodium chloride, said reducing agent for instance being sodium sulphide. In this case there is obtained as the end product, in addition to sodium chloride, also sodium sulphate and an extremely minor amount of colloidal sulphur. Since the seawater contains sodium chloride as well as sodium sulphate a discharge of the end product referred to into said recipient would be possible without causing any problems. As has already been stated above corresponding considerations are applicable to perbromic and periodic acids, bromide and iodide, respectively, being obtained. However, before said reduction of perchloric acid is performed any conventional purification of the solution may be accomplished. This can be made by adding after the finalized decontamination ascorbic acid in the desired concentration, for instance 1-2 g/l, the following reduction reactions taking place: Cr.sup.6+ present in the solution as chromate is reduced to Cr.sup.3+ PA1 Ce.sup.4+ is reduced to Ce.sup.3+ PA1 Fe.sup.3+ is reduced to Fe.sup.2+ PA1 O.sub.3 is reduced to O.sub.2. On the contrary the perchloric acid is not effected by the ascorbic acid. As an alternative to sodium sulphide as the reducing agent of this kind reference can be made to a hydroxylamine compound, for instance the nitrate, acetate or chloride. After the addition of ascorbic acid one can then perform a conventional purification with cation exchange resin, all metals and nuclides present being completely removed. The purified solution now contains perchloric acid plus a minor amount of nitric acid (for example in a concentration of about 25 g/l and 3.5 g/l, respectively). Then the reduction referred to above is performed with an inorganic reducing agent, for instance sodium sulphide. An alternative as concerns the waste handling means that the solution purified with a cation exchange resin is then purified with an anion exchange resin. After a treatment with lime the anion exchange resin mass is then cast throughout or within cement.
	claims	1. An apparatus for putting risers under tension, characterized in that it comprises vertical guides ( 7 ) in a derrick; toothed racks ( 4 ) in the vertical guides ( 7 ); a gripper means ( 5 , 12 ) designed for selectable interaction with a riser, connected ( 6 ) to the racks ( 4 ), and drive units ( 9 ) arranged in the derrick for drive-actuation of the racks ( 4 ) in the vertical guides ( 7 ), the gripper means maintaining the riser under tension when the gripper means interacts with the riser. 2. An apparatus according to claim 1 , characterised in that the gripper means includes a platform ( 5 ) having gripper members ( 12 ) for interaction with the riser. claim 1 3. An apparatus for putting risers under tension, characterized in that it comprises vertical guides ( 7 ) in a derrick; toothed racks ( 4 ) in the vertical guides ( 7 ); a gripper means ( 5 , 12 ) designed for interaction with a riser, connected ( 6 ) to the racks ( 4 ), and drive units ( 9 ) arranged in the derrick for drive-actuation of the racks ( 4 ) in the vertical guides ( 7 ); wherein the gripper means includes a platform ( 5 ) having gripper members ( 12 ) for interaction with the riser; the gripper members being in the form of flaps ( 12 ) supported in the platform so as to be capable of being swung towards one another, each flap having a recess ( 26 ) adapted to the half circumference of the riser. 4. An apparatus according to claim 1 , characterized in that the drive units ( 9 ) include hydraulic drive motors. claim 1 5. An apparatus according to claim 2 , characterized in that a rig floor ( 13 ) is capable of being connected to the racks ( 4 ). claim 2 6. An apparatus according to claim 1 , characterized in that the rig floor is connected to the toothed racks ( 4 ) by means of hydraulically actuated keys ( 14 ). claim 1 7. An apparatus according to claim 6 , characterised in that the rig floor ( 13 ) is connected to the hydraulically actuated keys ( 14 ) by means of hydraulic working cylinders ( 15 ) so that the drilling floor can be height-adjusted relative to the keys. claim 6 8. An apparatus for putting risers under tension, comprising: vertical guides in a derrick; toothed racks in the vertical guides; a gripper connected to the racks and adapted to selectably interact with a riser, the gripper maintaining the riser under tension when selectably interacting with the riser and for not maintaining the riser under tension when not selectably interacting with the riser; and drive units arranged in the derrick for drive-actuation of the racks in the vertical guides. 9. The apparatus according to claim 8 , wherein the gripper includes a plurality of flaps adapted to swing toward each other. claim 8 10. The apparatus according to claim 9 , wherein each of the flaps includes a recess adapted to a half circumference of the riser. claim 9 11. The apparatus according to claim 8 , wherein the gripper includes first and second flaps, each of the flaps adapted to move between horizontal and vertical positions, the gripper maintaining the riser under tension when each of the first and second flaps is in the horizontal position. claim 8
053373375	claims	1. A fuel assembly comprising a plurality of first fuel rods containing a nuclear fuel material free from a burnable poison and a plurality of second fuel rods containing the nuclear fuel material and the burnable poison, the plurality of the second fuel rods including (A) a plurality of second fuel rods containing a first burnable poison, located at positions in an outermost row in a cross-section of the fuel assembly, and (B) a plurality of second fuel rods containing a second burnable poison having a larger thermal neutron absorption cross-section than a thermal neutron absorption cross-section of the first burnable poison, located at positions in an inner region of the cross-section of the fuel assembly other than the outermost row. 2. A fuel assembly according to claim 1, wherein (A) the second fuel rods containing the first burnable poison are located at corners in the outermost row. 3. A fuel assembly according to claim 15, wherein the first burnable poison is boron and the second burnable poison is gadolinium. 4. A nuclear reactor core, comprising a plurality of fuel assemblies, at least one of the fuel assemblies including a plurality of first fuel rods containing a nuclear fuel material free from a burnable poison and a plurality of second fuel rods containing the nuclear fuel material and the burnable poison, the plurality of the second fuel rods comprising (A) a plurality of second fuel rods containing a first burnable poison, located at positions in an outermost row in a cross-section of the fuel assembly, and (B) a plurality of second fuel rods containing a second burnable poison having a larger thermal neutron absorption cross-section than a thermal neutron absorption cross-section of the first burnable poison, located at positions in an inner region of the cross-section of the fuel assembly other than the outermost row. 5. A nuclear reactor core according to claim 4, wherein (A) the second fuel rods containing the first burnable poison are located at corners in the outermost row. 6. A nuclear reactor core according to claim 4, wherein the first burnable poison is boron and the second burnable poison is gadolinium.
	claims	1. A system, comprising:a distribution conduit;at least two centrifugal machines configured to supply a working fluid to the distribution conduit, wherein one of the at least two centrifugal machines comprises a lead centrifugal machine and a second of the at least two centrifugal machines comprises a lag centrifugal machine;a working fluid parameter indicator that measures a process parameter associated with the working fluid supplied to the distribution conduit by the at least two centrifugal machines; anda controller that validates the sensitivity of the working fluid parameter indicator to measure the process parameter associated with the working fluid, the controller validating the sensitivity of the working fluid parameter indicator as a function of operation of the lag centrifugal machine relative to the lead centrifugal machine during an operational test of the centrifugal machines. 2. The system according to claim 1, wherein the operational test includes turning on the lag centrifugal machine while the lead centrifugal machine is on to contribute in sharing a load of supplying the working fluid to the distribution conduit, and turning off the lag centrifugal machine after operating in conjunction with the lead centrifugal machine for a predetermined period of time to transfer the load back to the lead centrifugal machine. 3. The system according to claim 2, wherein the controller receives a plurality of process parameter measurements from the working fluid parameter indicator during the operational test. 4. The system according to claim 3, wherein the controller compares the plurality of process parameter measurements to a baseline of previously obtained process parameter measurements. 5. The system according to claim 4, wherein the controller validates the sensitivity of the working fluid parameter indicator in response to determining that the plurality of process parameter measurements obtained during the operational test are within an acceptable range of deviation to the baseline of previously obtained process parameter measurements. 6. The system according to claim 3, wherein the controller forms an operational test signature from the plurality of process parameter measurements, wherein the operational test signature is characterized by a peak portion indicative of when the lag centrifugal machine turned on, a trough portion indicative of when the lag centrifugal machine turned off, a middle portion between the peak portion and the trough portion that is indicative of a stable state in which the lead centrifugal machine and the lag centrifugal machine share the load. 7. The system according to claim 6, wherein the controller compares the operational test signature to a baseline operational test signature having a baseline peak portion indicative of a turn-on event for the lag centrifugal machine, a baseline trough portion indicative of a turn-off event for the lag centrifugal machine, a baseline middle portion between the baseline peak portion and the baseline trough portion that is indicative of a stable operational running event in which the lead centrifugal machine and the lag centrifugal machine share the load. 8. The system according to claim 7, wherein the controller validates the sensitivity of the working fluid parameter indicator in response to determining that the peak portion, middle portion and trough portion of the operational test signature are within an acceptable range of deviation to the baseline peak portion, the baseline middle portion and the baseline trough portion of the baseline operational test signature, respectively. 9. The system according to claim 1, wherein the lead centrifugal machine and the lag centrifugal machine operate in parallel sharing the supply of the working fluid to the distribution conduit. 10. The system according to claim 1, further comprising a working fluid regulator that regulates the flow of the working fluid according to the process parameter measured by the working fluid parameter indicator. 11. A system, comprising:a distribution conduit;at least two redundant centrifugal machines configured to supply a working fluid to the distribution conduit, wherein one of the at least two redundant centrifugal machines comprises a lead centrifugal machine and a second of the at least two redundant centrifugal machines comprises a lag centrifugal machine;a flow splitter conduit that splits the flow of the working fluid from the at least two redundant centrifugal machines to the distribution conduit into different flow paths;one or more working fluid parameter indicators that measures a process parameter associated with the working fluid as supplied from the flow splitter conduit to the distribution conduit;a working fluid regulator located between the flow splitter conduit and the distribution conduit that regulates the flow of the working fluid therebetween according to the process parameter measured by the one or more working fluid parameter indicators; anda controller that validates the operational health of at least one of the working fluid parameter indicators and the working fluid regulator based on an operational test performed on the lead centrifugal machine and the lag centrifugal machine. 12. The system according to claim 11, wherein the operational test includes turning on the lag centrifugal machine while the lead centrifugal machine is on to contribute in sharing a load of supplying the working fluid to the distribution conduit, and turning off the lag centrifugal machine after operating in conjunction with the lead centrifugal machine for a predetermined period of time to transfer the load back to the lead centrifugal machine. 13. The system according to claim 12, wherein the controller receives a plurality of process parameter measurements from each of the working fluid parameter indicators during the operational test. 14. The system according to claim 13, wherein the controller compares the plurality of process parameter measurements to a baseline of previously obtained process parameter measurements. 15. The system according to claim 14, wherein the controller validates the operational health of at least one of the working fluid parameter indicators and the working fluid regulator in response to determining that the plurality of process parameter measurements obtained during the operational test are within an acceptable range of deviation to the baseline of previously obtained process parameter measurements. 16. The system according to claim 13, wherein the controller forms an operational test signature from the plurality of process parameter measurements, wherein the operational test signature is characterized by a peak portion indicative of when the lag centrifugal machine turned on, a trough portion indicative of when the lag centrifugal machine turned off, a middle portion between the peak portion and the trough portion that is indicative of a stable state in which the lead centrifugal machine and the lag centrifugal machine share the load. 17. The system according to claim 16, wherein the controller compares the operational test signature to a baseline operational test signature having a baseline peak portion indicative of a turn-on event for the lag centrifugal machine, a baseline trough portion indicative of a turn-off event for the lag centrifugal machine, a baseline middle portion between the baseline peak portion and the baseline trough portion that is indicative of a stable operational running event in which the lead centrifugal machine and the lag centrifugal machine share the load. 18. The system according to claim 17, wherein the controller validates the operational health of at least one of the working fluid parameter indicators and the working fluid regulator in response to determining that the peak portion, middle portion and trough portion of the operational test signature are within an acceptable range of deviation to the baseline peak portion, the baseline middle portion and the baseline trough portion of the baseline operational test signature, respectively. 19. The system according to claim 11, wherein the lead centrifugal machine and the lag centrifugal machine operate in parallel sharing the supply of the working fluid to the distribution conduit. 20. The system according to claim 11, further comprising an orifice valve located between the flow splitter conduit and the distribution conduit, wherein the orifice valve is located along a first flow path between the flow splitter conduit and the distribution conduit and the working fluid regulator is located along a second flow path between the flow splitter conduit and the distribution conduit.
	description	1. Field of the Invention The present invention relates to an optical axis adjusting mechanism for X-ray lens for adjusting an optical axis of an X-ray lens implemented in an X-ray analytical instrument, an X-ray analytical instrument, and a method of adjusting an optical axis of an X-ray lens. 2. Description of the Related Art In recent years, an X-ray analytical instrument for detecting an X-ray emitted from a sample in response to electron beam irradiation on the sample has been known to the public. A superconducting X-ray detector is preferably used as the X-ray analytical instrument of this kind because it dramatically enhances the energy resolution from the conventional level. Incidentally, since the traveling directions of the emitted X-rays are individually different, it is desirable to enlarge the area of a receiver section of the detector in order for enhancing the receiving efficiency of the detector. However, in order for enhancing the energy resolution of the detector, the X-ray detector, in particular the superconducting X-ray detector has no other choice than reducing the area of the receiver section. As a result, the detection efficiency of the X-rays emitted from the sample decreases. To cope with the above, the use of an X-ray lens is thought to be effective for enhancing the detection efficiency, and a method of applying a multispindle goniometer to optical axis adjustment is reported (See Giorgio Cappuccio et. al., “Capillary optics as an X-ray condensing lens: An alignment procedure” Kumakhov optics and application: selected research papers on Kumakhov optics and application 1998-2000 Edited by Muradin A. Kumakhov. Bellingham, Wash., USA: SPIE, c2000). In the method of adjusting the optical axis while mounting the X-ray lens on the multispindle goniometer, however, it is difficult to dispose a sample, a sample stage, an excitation source such as an electron gun or an X-ray source, a superconducting X-ray detector, and other analytical detectors in a limited space, and accordingly, the detectors need to be set apart from the sample, thus problematically degrading the device performance. Therefore, an object of the invention is to provide an optical axis adjusting mechanism for an X-ray lens, an X-ray analytical instrument and a method of adjusting an optical axis of an X-ray lens, capable of enhancing detection efficiency of an X-ray while preventing degradation of the device performance. An optical axis adjusting mechanism according to an aspect of the invention includes an exit side adjusting mechanism for adjusting an exit side focal point of the X-ray lens to focus on an X-ray detector, and an entrance side adjusting mechanism for adjusting an entrance side focal point of the X-ray lens to focus on an analytical point of a sample, and the entrance side adjusting mechanism is disposed with a greater distance from the X-ray lens than a distance between the exit side adjusting mechanism and the X-ray lens. According to this aspect of the invention, firstly the exit side focal point of the lens is adjusted by the exit side adjusting mechanism to focus on the X-ray detector, and by adjusting the entrance side focal point to focus on the analytical point of the sample by the entrance side adjusting mechanism in this state, the X-ray emitted from the sample and then collected by the X-ray lens can be detected by the detector, thus the detection efficiency can be enhanced. And further, since the entrance side adjusting mechanism is disposed with a greater distance from the X-ray lens than the distance between the exit side adjusting mechanism and the X-ray lens, the entrance side adjusting mechanism can be operated for focusing on the sample without disturbing the X-ray analytical instrument, thus enhancing workability. And, according to this aspect of the invention, since the space necessary for focusing on the sample can be reduced, the analytical detectors such as the superconducting X-ray detector can be disposed in the limited space, thus the detection efficiency of the X-ray can be enhanced while preventing degradation of the device performance. Further, the exit side adjusting mechanism preferably includes a mechanism capable of translating the X-ray lens in parallel with two directions perpendicular to the optical axis of the X-ray lens. Thus, the focal point can be adjusted to focus on the X-ray detector by translating in parallel with two directions perpendicular to the optical axis of the X-ray lens in adjusting the exit side focal point. Further, the exit side adjusting mechanism preferably includes a mechanism capable of rotationally moving the X-ray lens around two axes passing through the entrance side focal point of the X-ray lens and perpendicular to the optical axis of the X-ray lens. By thus arranging the configuration, the exit side focal point position can be adjusted without changing the entrance side focal point position. Further, the exit side adjusting mechanism preferably includes a detachable section configured to allow at least a portion operated by an operator to be detached. Thus, the operator can execute the operation more easily in adjusting the exit side focal point to focus on the X-ray detector by executing the operation while the detachable section is attached. And, by removing the detachable section therefrom after adjusting the exit side focal point of the lens to focus on the X-ray detector, the exit side adjusting mechanism can be prevented from disturbing the adjustment by the entrance side adjusting mechanism for focusing the entrance side focal point on the analytical point of the sample, thus enhancing the workability. Further, the X-ray lens is preferably equipped with a holding mechanism for keeping the X-ray lens in a position adjusted by the exit side adjusting mechanism. Accordingly, the exit side focal point of the lens is firstly adjusted by the exit side adjusting mechanism, and then, while keeping the adjusted position with the holding mechanism, the entrance side focal point of the X-ray lens can be adjusted by the entrance side adjusting mechanism, thus enhancing the workability. Note that in the case that the exit side adjusting mechanism includes the detachable section, the entrance side focal point of the lens can be adjusted while the holding mechanism keeps the adjusted position of the exit side focal point of the lens and the detachable section is removed, thus the workability can further be enhanced. Further, the X-ray detector is preferably a superconducting X-ray detector mounted on a refrigerator, the entrance side adjusting mechanism is preferably disposed adjacent to the refrigerator, and the exit side adjusting mechanism can preferably be moved integrally with the refrigerator. Accordingly, by moving the exit side adjusting mechanism integrally with the refrigerator in adjusting the entrance side focal point of the X-ray lens by the entrance side adjusting mechanism to focus on the analytical point of the sample, the entrance side focal point of the lens can be adjusted while keeping the positional relationship between the exit side focal point and the detector, and keeping the temperature of the X-ray detector at a predetermined level by the refrigerator, thus the workability can be enhanced. Further, the entrance side adjusting mechanism preferably includes a mechanism capable of translating the refrigerator in parallel with two directions traversing the optical axis of the X-ray lens. Namely, the configuration includes two kinds of parallel translations. Accordingly, by translating the refrigerator in parallel with two directions traversing the optical axis of the X-ray glens in adjusting the entrance side focal point, the X-ray lens can be moved integrally with the refrigerator to focus on the analytical point of the sample. Therefore, in implementing the X-ray lens in the instrument on which the sample is mounted, there is no need to implement it in a condition in which the adjustment in the two directions traversing the optical axis has been executed previously, but it is enough to execute the adjustment of the X-ray lens by the entrance side adjusting mechanism after it is implemented. Thus, the requirement for the positional accuracy of the X-ray lens in implementation in the instrument on which the sample is mounted can be eased, thus enhancing the workability. Further, it is preferable that the two directions are substantially perpendicular to the optical axis of the X-ray lens. Accordingly, the movement of the X-ray lens in the optical axis direction in adjusting the entrance side focal point can be suppressed, thus the risk of defocus in the optical axis direction can be avoided. Thus, the adjustable range of the parallel translation can be extended to ease the requirement for the positional accuracy of the X-ray lens in implementing the X-ray lens in the instrument on which the sample is mounted, thus enhancing the workability. Further, the entrance side adjusting mechanism preferably includes a mechanism capable of translating the refrigerator in parallel with a horizontal direction perpendicular to the optical axis of the X-ray lens. Namely, the configuration includes one kind of parallel translation. Accordingly, by translating the refrigerator in parallel with the horizontal direction substantially perpendicular to the optical axis of the X-ray lens in adjusting the entrance side focal point, the X-ray lens can be moved integrally with the refrigerator to focus on the analytical point of the sample. Therefore, in implementation in the instrument on which the sample is mounted, there is no need to implement it in a condition in which the adjustment in the translatable direction described above has been executed, but it is enough to execute the adjustment of the X-ray lens by the entrance side adjusting mechanism after it is implemented. Thus, the requirement for the positional accuracy of the X-ray lens in implementation in the instrument on which the sample is mounted can be eased, thus enhancing the workability. Note that in the case that a positional adjustment in the direction perpendicular to the translatable direction is necessary, the adjustment can be executed by changing the irradiation position of the excitation source taking a measure of, for example, changing the focal distance of the electron gun. Further, the entrance side adjusting mechanism preferably includes a mechanism capable of rotationally moving the refrigerator around each of two axes positioned differently from the optical axis of the X-ray lens and passing through the refrigerator or an area adjacent to the refrigerator. Namely, the configuration includes two kinds of rotational movements. Accordingly, by rotationally moving the refrigerator around each of two axes positioned differently from the optical axis of the X-ray lens and passing through the refrigerator or an are adjacent to the refrigerator in adjusting the entrance side focal point, the X-ray lens can be moved integrally with the refrigerator to focus on the analytical point of the sample. Therefore, in implementing the X-ray lens in the instrument on which the sample is mounted, there is no need to implement it in a condition in which the positional adjustment of the X-ray lens in the rotationally movable direction described above has been executed previously, but it is enough to execute the adjustment of the X-ray lens by the entrance side adjusting mechanism after it is implemented. Thus, the requirement for the positional accuracy of the X-ray lens in implementing it in the instrument on which the sample is mounted can be eased, thus enhancing the workability. Further, the entrance side adjusting mechanism preferably includes a mechanism capable of rotationally moving the refrigerator around a rotational axis positioned differently from the optical axis of the X-ray lens and passing through the refrigerator or an area adjacent to the refrigerator, and it is preferable that the rotational axis the mechanism rotationally moves the refrigerator around is substantially perpendicular to the ground. Namely, the configuration includes one kind of rotational movement. Accordingly, by rotationally moving the refrigerator around the rotational axis in adjusting the entrance side focal point, the X-ray lens can be moved integrally with the refrigerator to focus on the analytical point of the sample. Therefore, in implementation in the instrument on which the sample is mounted, there is no need to implement it in a condition in which the positional adjustment of the X-ray lens in the movable direction in accordance with the rotational movement described above has been executed, but it is enough to execute the adjustment of the X-ray lens by the entrance side adjusting mechanism after it is implemented. Thus, the requirement for the positional accuracy of the X-ray lens in implementation in the instrument on which the sample is mounted can be eased, thus enhancing the workability. Note that in the case that a positional adjustment in the direction perpendicular to the translatable direction is necessary, the adjustment can be executed by changing the irradiation position of the excitation source taking a measure of, for example, changing the focal distance of the electron gun. Further, the entrance side adjusting mechanism preferably moves the entrance side focal point of the X-ray lens approximately parallel to a direction substantially perpendicular to the optical axis of the X-ray lens by the rotational movement around the rotational axis. Accordingly, the movement of the X-ray lens in the optical axis direction in adjusting the entrance side focal point can be suppressed, thus the risk of defocus in the optical axis direction can be avoided. Thus, the adjustable range of the rotational movement can be extended to ease the requirement for the positional accuracy of the X-ray lens in implementing it in the instrument on which the sample is mounted, thus enhancing the workability. Further, the entrance side adjusting mechanism preferably includes a mechanism capable of moving the entrance side focal point of the X-ray lens integrally with the refrigerator in a horizontal direction. Accordingly, by moving the refrigerator in the horizontal direction in adjusting the entrance side focal point, the X-ray lens can be moved in the horizontal direction integrally with the refrigerator to focus on the analytical point of the sample. Therefore, in implementation in the instrument on which the sample is mounted, there is no need to implement it in a condition in which the positional adjustment of the X-ray lens in the horizontal direction has been executed previously, but it is enough to execute the adjustment of the X-ray lens by the entrance side adjusting mechanism after it is implemented. Thus, the requirement for the positional accuracy of the X-ray lens in implementation in the instrument for adjusting the entrance side focal point can be eased, thus enhancing the workability. Further, the entrance side adjusting mechanism preferably includes a mechanism capable of translating the entrance side focal point of the X-ray lens integrally with the refrigerator in parallel with a direction traversing the optical axis of the X-ray lens, and a mechanism capable of rotationally moving the entrance side focal point of the X-ray lens integrally with the refrigerator around an axis positioned differently from the optical axis of the X-ray lens. Namely, the configuration includes one kind of parallel translation and one kind of rotational movement. Accordingly, by translating in parallel and rotationally moving the refrigerator with respect to the axes having the relationship described above with the optical axis in adjusting the entrance side focal point, the X-ray lens can be moved integrally with the refrigerator to focus on the analytical point of the sample. Therefore, in implementation in the instrument on which the sample is mounted, there is no need to implement it in a condition in which the adjustment in the parallel translatable direction and the rotationally movable direction described above has been executed, but it is enough to execute the adjustment of the X-ray lens by the entrance side adjusting mechanism after it is implemented. Thus, the requirement for the positional accuracy of the X-ray lens in implementing in the instrument on which the sample is mounted can be eased, thus enhancing the workability. Further, the entrance side adjusting mechanism is preferably capable of adjusting the entrance side focal point of the X-ray lens, while firmly connecting a stage mounting the entrance side adjusting mechanism to an analytical vessel containing the sample, an excitation source and a detector, and then inserting the X-ray lens in the analytical vessel. Accordingly, the entrance side focal point of the X-ray lens can be adjusted by adjusting the position of the refrigerator by the entrance side adjusting mechanism while the stage is firmly connected to the analytical vessel, thus the workability can be enhanced. Further, the entrance side adjusting mechanism is preferably capable of adjusting the entrance side focal point of the X-ray lens, while connecting the refrigerator to a scanning electron microscope via a bellows, and firmly connecting a stage mounting the entrance side adjusting mechanism to the scanning electron microscope, and then inserting the X-ray lens in a vacuum vessel of the scanning electron microscope. Accordingly, the entrance side focal point of the X-ray lens can be adjusted by adjusting the position of the refrigerator by the entrance side adjusting mechanism while the stage is firmly connected to the scanning electron microscope, thus the workability can be enhanced. Further, a method of adjusting an optical axis according to another aspect of the invention includes the step of disposing an entrance side adjusting mechanism for adjusting an entrance side focal point of the X-ray lens to focus on an analytical point of a sample with a greater distance from the X-ray lens than a distance between an exit side adjusting mechanism for adjusting an exit side focal point of the X-ray lens to focus on an X-ray detector and the X-ray lens, the step of adjusting, by the exit side adjusting mechanism, the exit side focal point of the X-ray lens to focus on the X-ray detector, and the step of adjusting, by the entrance side adjusting mechanism, the entrance side focal point of the X-ray lens to focus on the analytical point of the sample after adjusting the exit side focal point. According to this aspect of the invention, the entrance side adjusting mechanism can be operated without disturbing the X-ray analytical instrument in focusing on the sample, thus the workability can be enhanced. Further, an X-ray analytical instrument according to still another aspect of the invention includes the optical axis adjusting mechanism for an X-ray lens described above. Accordingly, the entrance side adjusting mechanism can be operated without disturbing the X-ray analytical instrument in focusing on the sample, thus the workability can be enhanced. According to the invention, the detection efficiency of an X-ray can be enhanced while preventing degradation in the performance of the instrument. An optical axis adjusting mechanism for X-ray lens, an X-ray analytical device and a method of adjusting an optical axis of an X-ray lens according to each of embodiments of the invention will hereinafter be explained with reference to the accompanying drawings. FIG. 1 is a schematic cross-sectional view of an X-ray analytical device equipped with an optical axis adjusting mechanism for an X-ray lens according to an embodiment of the invention. As shown in the drawing, the X-ray analytical device 11 according to the present embodiment is used while being mounted in a scanning electron microscope (SEM for short) 7 for detecting X-rays emitted from a sample 10 held in the scanning electron microscope 7, thereby analyzing the sample. The X-ray analytical device 11 has a configuration in which an X-ray lens 1 is mounted on the tip of a snout 3, which has an elongate cylindrical shape, to be inserted in the scanning electron microscope 7. The X-ray lens 1 is disposed so that the entrance side surface thereof faces the sample 10 held in the scanning electron microscope 7. Meanwhile, an X-ray detector 9 is disposed inside the snout 3 so as to face the exit side surface of the X-ray lens 1. A superconducting X-ray detector is used as the X-ray detector 9 in the present embodiment. And, a refrigerator 6 is disposed in a base end side of the snout 3, and the superconducting X-ray detector 9 is refrigerated to a predetermined temperature near to the transition end by the refrigerator 6. The snout 3 is provided integrally with the refrigerator 6 in the present embodiment. Accordingly, the focal point of the entrance side (the sample 10 side) of the X-ray lens 1 mounted on the snout 3 can be adjusted by operating an entrance side adjusting mechanism (the specific configuration thereof will be described later with reference to FIGS. 9 through 18) 13 to move the refrigerator 6, and therefore the snout 3 integrally provided to the refrigerator 6, in two directions perpendicular to the optical axis L as illustrated with the arrows. Meanwhile, an exit side adjusting mechanism 12 is provided on a tip portion of the snout 3, and the focal point of the exit side (the detector 9 side) of the X-ray lens 1 can be adjusted by operating the exit side adjusting mechanism 12. FIG. 2 is a schematic cross-sectional view of the exit side adjusting mechanism provided on the tip portion of the snout. As shown in the drawing, the tip portion of the snout 3 is provided with a lens holder slide 4 capable of sliding a lens holder 2 for holding the X-ray lens 1 in a substantially perpendicular direction with respect to the optical axis L. The exit side focal point of the X-ray lens 1 is adjusted to focus on the superconducting X-ray detector 9 by operating the lens holder slide 4. FIG. 3 is a schematic cross-sectional view of the entrance side adjusting mechanism disposed in the refrigerator side. As shown in the drawing, the X-ray analytical device 11 is adjusted, while the tip portion of the snout 3 is inserted in a vessel of the scanning electron microscope 7 holding the sample 10 inside, by the entrance side adjusting mechanism 13 mounted on the refrigerator 6 integrally coupled to the snout 3 so as to adjust the entrance side focal point of the X-ray lens 1 to focus on the sample 10. In this case, a bellows 8 is mounted between the vessel of the scanning electron microscope 7 and the refrigerator 6 and in the periphery of the snout 3, and the exit side focal point of the X-ray lens can be adjusted by moving the snout 3 integrally with the refrigerator 6 while maintaining the contact between the X-ray analytical device 11 and the scanning electron microscope 7 by the bellows 8. Now, the characteristics of the X-ray lens 1 will be explained with reference to FIG. 4. FIG. 4 is an explanatory diagram showing necessary accuracy in adjusting the focal points of the X-ray lens. As shown in the drawing, the X-ray lens 1 is formed to have focusing accuracy required in a direction along the optical axis L of 2 mm and focusing accuracy required in a direction perpendicular to the optical axis L of 100 nm. Namely, the X-ray lens 1 has characteristics requiring relatively low focusing accuracy in the direction along the optical axis L while requiring relatively high accuracy in the direction perpendicular to the optical axis L. Note that the numerical values shown in the drawing are examples only, and it is obvious that the focusing accuracy is not limited to the numeral values. FIG. 5 is an explanatory view showing a condition of an exit side adjustment processing device with the snout mounted thereon. As shown in the drawing, the exit side adjustment processing device is equipped with a vessel 28 formed substantially hollow and having a substantially rectangular cross-section, an X-ray source 27 mounted inside the vessel 28 for emitting an X-ray in a predetermined direction, and a micrometer 26 for adjusting the position of the X-ray source 27. And, the exit side position of the X-ray lens 1 is adjusted by operating micrometers 25 mounted on the tip portion of the snout 3 to slide the lens holder 2 accommodating the X-ray lens 1 in a condition in which the tip portion of the snout 3 is inserted from an opening section (not shown) of the vessel 28. FIG. 6 is a cross-sectional view showing a substantial part of the exit side adjusting mechanism provided on the tip portion of the snout. As shown in the drawing, the lens holder slide 4 is provided with slots 31 for inserting the micrometers 25 formed in the circumferential surface thereof. FIG. 7 is a plan view showing the exit side adjusting mechanism. As shown in the drawing, the micrometers 25 are implemented to the inserting slots 31 at the tip end part of the snout 3, and an operator operates the micrometers 25 to execute the exit side adjustment of the X-ray lens 1. Further, a frame 37 for holding the micrometers 25 is disposed in the periphery of the snout 3. As described above, the micrometers 25 to be operated by the operator are arranged to be detachable from the snout 3. FIG. 8 is a cross-sectional view showing an internal structure of the exit side adjusting mechanism shown in FIG. 7. As shown in the drawing, pressing components 36 for holding the lens holder slide 4 with pressure are mounted on tip portions of the micrometers 25 and inside the frame 37. The positions of the pressing components 36 can be shifted alternatively near to and apart from the lens holder slide 4 by rotating the respective micrometers 25 in forward and backward directions, respectively. Further, the frame 37 has a pushing spring 38 built-in for biasing the lens holder slide 4 in a direction for abutting on the pressing components 36. Therefore, the position of the lens holder slide 4 can be controlled by operating the micrometers 25 to shift the positions of the pressing components 36, thereby adjusting the exit side focal point of the X-ray lens 1 held in the lens holder slide 4. Further, holding screws 33 are provided for keeping the position of the lens holder slide 4. FIG. 9 is a schematic cross-sectional view showing a rough outline of the entrance side adjusting mechanism. FIG. 10 is a schematic plan view of the entrance side adjusting mechanism shown in FIG. 9. As shown in FIG. 9, a refrigerator supporting member 46 mounted on the lower surface of the refrigerator 6 and a receiving section 45 of a bracket 41 fixed to the vessel of the scanning electron microscope 7 along the side surface thereof are connected with each other via a turntable member 44. The turntable member 44 is rotatably mounted on the receiving section 45 via a spindle 42 provided in a center portion of the turntable member 44. Thus, the turntable member 44 can rotate with respect to the receiving section 45 alternatively in forward and backward directions, accompanied by the refrigerator 6 coupled to the turntable member 44 rotating around the spindle 42 (See FIG. 10). Further, the supporting member 46 is pivotally mounted on the turntable member 44 via a rotary shaft 43. Thus, the refrigerator 6 coupled to the supporting member 46 can be pivoted around the rotary shaft 43. By thus rotationally moving the refrigerator 6, the snout 3 integrally coupled to the refrigerator 6 and further the entrance side focal point of the X-ray lens 1 mounted on the tip potion of the snout 3 can be adjusted. FIG. 11 is a schematic plan view showing a rough outline of another entrance side adjusting mechanism. FIG. 12 is a schematic cross-sectional view of the entrance side adjusting mechanism shown in FIG. 11. FIG. 13 is a schematic rear view of the entrance side adjusting mechanism shown in FIG. 11. As shown in these drawings, the supporting member 46 for supporting the refrigerator 6 is supported at three points via an adjusting plate 51 connected to the bracket 41. In other words, by using a supporting protrusion 53, which is formed substantially on the center axis of the snout 3 from a view point in the height direction, as a base point, and changing the heights of adjusting screws 52 formed on lines traversing the center axis of the snout 3, the position of the refrigerator 6 can be adjusted, thus the entrance side focal point of the X-ray lens 1 can be adjusted. FIG. 14 is a schematic cross-sectional view showing a rough outline of still another entrance side adjusting mechanism. As shown in the drawing, the supporting member 46 for supporting the refrigerator 6 and the bracket 41 are connected to each other via a sliding member 62. The sliding member 62 is formed to be able to slide as illustrated with the arrow P along a slide guide 61 provided to the bracket 41. Thus, with such movement of the sliding member 62, the refrigerator 6 coupled to the supporting member 46 can also slide as illustrated with the arrow P. Further, the supporting member 46 can slide along a sliding guide 63 provided to the sliding member 62 in directions of the arrow Q (the directions perpendicular to the sheet). By thus sliding the refrigerator 6 in the directions of arrows P and Q (either direction is substantially perpendicular to the optical axis of the X-ray lens 1), the entrance side focal point of the X-ray lens 1 connected to the refrigerator 6 can be adjusted in two directions perpendicular to the optical axis thereof. FIG. 15 is a schematic cross-sectional view showing a rough outline of still another entrance side adjusting mechanism. As shown in the drawing, the supporting member 46 for supporting the refrigerator 6 and the bracket 41 are connected to each other via a sliding member 72. The sliding member 72 is formed to be able to slide as illustrated with the arrow Q along a slide guide 71 provided to the bracket 41. Thus, with such movement of the sliding member 72, the refrigerator 6 coupled to the supporting member 46 can also slide as illustrated with the arrow Q. Further, the sliding member 72 is pivotally connected to the supporting member 46 via the rotary shaft 43. Thus, the supporting member 46 can be pivoted around the rotary shaft 43 alternatively in forward and backward directions. Accordingly, similarly to other embodiments described above, by sliding or rotationally moving the refrigerator 6, the snout 3 integrally coupled to the refrigerator 6 and further the entrance side focal point of the X-ray lens 1 mounted on the tip potion of the snout 3 can be adjusted. FIG. 16 is a schematic cross-sectional view showing a rough outline of still another entrance side adjusting mechanism. Further, FIG. 17 is a perspective view showing a substantial part of the entrance side adjusting mechanism shown in FIG. 16, and FIG. 18 is a cross-sectional view in the direction perpendicular to the direction of FIG. 16. As shown in these drawings, the supporting member 46 for supporting the refrigerator 6 and the bracket 41 are pivotally connected to each other via the rotary shaft 43. Thus, the supporting member 46 can be pivoted around the rotary shaft 43 alternatively in forward and backward directions. Further, in the present embodiment, as shown in FIG. 18, the rotary shaft 43 is pivotally mounted between protruding sections 81 extending below the supporting member 46 so as to pass through a receiving section 82. Therefore, the supporting member 46 can be shifted with respect to the receiving section 82 along the center axis direction (denoted by the arrow Q) of the rotary shaft 43. Accordingly, similarly to other embodiments described above, by sliding or rotationally moving the refrigerator 6, the snout 3 integrally coupled to the refrigerator 6 and further the entrance side focal point of the X-ray lens 1 mounted on the tip potion of the snout 3 can be adjusted. FIG. 19 is a schematic cross-sectional view showing a rough outline of another example of the exit side adjusting mechanism. In the exit side adjusting mechanism having the configuration shown in the drawing, the x-ray lens 1 is arranged to be able to rotationally move around two axes each passing through the entrance side focal point (the X-ray source 27 in this vessel) and perpendicular to the optical axis L. In other words, in the drawing, the axes R1 and R2 are both perpendicular to the optical axis L, and the axis R1 is arranged in the direction perpendicular to the sheet while the axis R2 is arranged in the same plane as the sheet, namely in the direction perpendicular to the axis R1. Accordingly, the X-ray lens 1 rotationally moves on a rotational locus r1, which is a circle within the same plane as the sheet, taking the axis R1 as the rotational axis. Further, the X-ray lens 1 rotationally moves on a rotational locus r2 (for the sake of convenience of illustration, a circular arc in an oblique plane is illustrated in FIG. 19), which is a circle within a plane perpendicular to the sheet, taking the axis R2 as the rotational axis. By thus arranging the configuration, the exit side focal point position can be adjusted without changing the entrance side focal point position. Note that it is obvious that the axes R1 and R2 are not limited to the above arrangement, provided the axes R1 and R2 are perpendicular to the optical axis L. Although the content of the invention is explained with reference to the embodiments as described above, it is obvious that the content of the invention is not limited to the embodiments only. For example, although the case of the application to the superconducting X-ray detector is explained in the embodiments, the application is not so limited, but the application to other types of X-ray detectors such as an X-ray detector utilizing a silicon detector is also possible.
047298553	description	DESCRIPTION OF THE INVENTION It is an object of the process of this invention to reduce the radioactivity of metal surfaces having radioactive deposits thereon. This is accomplished by passing over the surface an aqueous solution that contains the water soluble condensation reaction product formed when a water soluble aliphatic polycarboxylic acid reacts with a hydrazine compound having the general formula: ##STR2## where each R group in the formula is independently selected from hydrogen and alkyl to C.sub.4. The R group is preferably hydrogen because when the R group is alkyl, an alcohol is emitted (instead of water) which creates an additional handling problem and, also, the hydrogen compound, hydrazine, is more effective. The water soluble aliphatic polycarboxylic acid may be any aliphatic organic acid containing two or more carboxylic acid groups which will react with the hydrazine compound to form a condensation reaction product. Preferably, the polycarboxylic acid contains two carboxylic acid groups, as those compounds tend to be more soluble and more easily oxidized, and are more reactive with the hydrazine compound. The preferred polycarboxylic acid is oxalic acid, although tartaric acid, citric acid, nitrilotriacedic acid, ethylenediaminetetraacedic acid, succinic acid, and other polycarboxylic acids can also be used. The condensation reaction product can be formed by stoichiometrically reacting (plus or minus about 10 mole percent) the hydrazine compound with the aliphatic polycarboxylic acid. It is preferable to react one mole of the hydrazine compound for each equivalent of the polycarboxylic acid so that each carboxylic acid group on the aliphatic polycarboxylic acid is reacted with one hydrazine compound molecule. However, it is also possible to leave some free carboxylic acid groups on the condensation reaction product by reacting less than one mole of the hydrazine compound with each equivalent of the polycarboxylic acid. A one-to-one equivalent ratio is preferred as it seems to produce a stronger chelant. Thus, dihydrazine oxalate is preferred to mono-hydrazine oxalate. The reaction will proceed without a catalyst in water at about a 5% concentration between room temperature and about 50.degree. C., and is complete in about one to four hours. The resulting solution can be used directly, or it can be evaporated to solids and the solids used to form the decontamination solution. The decontamination solution is formed by making an aqueous solution of the condensation reaction product at a concentration of about 0.05 to about 10% by weight based on total solution weight; less than about 0.05% is ineffective and more than about 10% is unnecessary. The decontamination solution is circulated over the deposit on the metal surface for about 2 to 24 hours at a temperature of about 80.degree. to about 125.degree. C., though times and temperatures can vary as desired. After the solution has contacted the deposit, it is passed through a cationic ion exchange column to remove whatever metal ions have been chelated by the condensation reaction product. The cationic ion exchange resin can be formed with a strong acid or a weak acid, and can be loaded with a variety of cations, but it is preferable to load the column with N.sub.2 H.sub.5.sup.+ or the cationic moiety of the condensation reaction product. For example, if N.sub.2 H.sub.3 CH.sub.3 is used to form the condensation reaction product, the cationic exchange column would be loaded with N.sub.2 H.sub.5.sup.+ or, preferably, with N.sub.2 H.sub.4 CH.sub.3.sup.+, to prevent the hydrazine moiety of the condensation reaction product from being loaded onto the column in preference to the chelated metal ions. A further advantage of preloading the ion exchange column with the cationic moiety of the condensation reaction product is that an excess of that moiety is a reducing agent and reduces metal ions, such as ferric, to less corrosive and more soluble forms, such as ferrous. If metal surfaces from a pressurized water reactor, such as steam generator tubes, are to be treated, is it preferable to follow the decontamination solution with a rinsing, then with an oxidizing solution, followed by a second rinse and a second treatment with the decontamination solution. This three step procedure is more effective in reducing decontamination, and results in a larger decontamination factor (DF, radioactivity before treatment divided by radioactivity after treatment). Oxidizing solutions are well known in the art and typically include alkali permanganates (i.e., mixtures of alkali metal hydroxides and alkali metal permanganates), such as an aqueous solution of 2% potassium permanganate and 10% sodium hydroxide. If the metal surfaces are from a boiling water reactor, the oxidation step, while it may be useful, can be omitted. When the decontamination solution is exhausted or must be disposed of, it is mixed with an oxidizing agent which oxidizes the condensation reaction product to nitrogen, carbon dioxide, and water. Suitable oxidizing agents include ozone and hydrogen peroxide. Hydrogen peroxide is preferred as it is readily available, inexpensive, and produces a minimum amount of solids. The oxidant should be added at a concentration of preferably between about stoichiometric and about 10 mole percent in excess of stoichiometric, although up to five times stoichiometric can be used. If the metal surfaces are treated with a separate oxidizing solution, such as an alkali permanganate, the decontamination solution may be mixed with the alkali permanganate solution to destroy the condensation reaction product. If an "R" group in the above general formula is alkyl, a higher temperature and oxidant concentration will be required to fully oxidize the condensation reaction product to gases than if the "R" groups are all hydrogen. The following examples further illustrate this invention. EXAMPLE A hydrazine oxalate condensation reaction product was prepared by adding 37.43 grams of hydrazine and 52.63 grams of oxalic acid to 1000 milliliters of water. The mixture was heated at 50.degree. C. for four hours and was then evaporated to dryness under a vacuum at 50.degree. C. to produce a white powder of hydrazine oxalate. A decontamination solution was prepared by adding 2.459 grams of the hydrazine oxalate to 700 milliliters of water to form a 0.35 percent by weight hydrazine oxalate solution. The solution was heated to 90.degree. C. An actual pressurized water reactor Inconel tube specimen having a radioactive deposit thereon was placed in the heated solution for two hours without agitation. The specimen was removed, rinsed, and placed in a 5% solution of 0.83% potassium permanganate and 4.17% sodium hydroxide for two hours at 95.degree. C. without agitation. The specimen was rinsed and again placed in fresh hydrazine oxalate decontamination solution again for two hours at 90.degree. C. with no agitation. A decontamination factor of 8.06 was obtained with most of the activity removal occurring in the last step. This is regarded as a good result considering that the specimen was exposed for only two hours, at a low concentration, without agitation, and at only 90.degree. C.
	claims	1. An apparatus for simultaneously measuring two fuel rods assembled in a nuclear fuel assembly, the apparatus comprising:a frame installed in a vertical direction;a cylinder supported by the frame and configured to move vertically along the frame;a first probe disposed at a first side of the cylinder, the cylinder configured to move the first probe vertically, the first probe configured to measure a cladding of a first fuel rod that is at a periphery of the nuclear fuel assembly, the first probe including:a first lower plate mounted on the cylinder and configured to support the first probe,a fuel rod guide part disposed on the first lower plate and having a semi-circular channel shape formed in the vertical direction, the fuel rod guide part configured to move along the first fuel rod,a guide roller mounted above the fuel rod guide part disposed on the first lower plate and configured to guide the first probe along the first fuel rod,a first eddy current sensor mounted on the fuel rod guide part and configured to detect an amount of eddy current induced on the first fuel rod, andat least one supporting guide part disposed on the first lower plate side by side with the fuel rod guide part, the supporting guide part having a semi-circular channel shape and being configured to move along a neighboring fuel rod placed next to the first fuel rod; anda second probe disposed at a second side of the cylinder and configured to simultaneously measure a cladding of a second fuel rod that is disposed at an interior position of the nuclear fuel assembly not adjacent to the first fuel rod. 2. The apparatus as set forth in claim 1, wherein the first probe is configured to measure the cladding of the first fuel rod of the nuclear fuel assembly using the first eddy current sensor while the first eddy current sensor moves in the vertical direction along the first fuel rod. 3. The apparatus as set forth in claim 1, wherein the second probe includes: a second lower plate mounted on the cylinder and supporting the second probe, a strip disposed on the second lower plate, having a thin and long strip shape configured to be inserted between fuel rods in the nuclear fuel assembly; and a second eddy current sensor mounted on one end of the strip and configured to measure the cladding of the second fuel rod of the nuclear fuel assembly. 4. The apparatus as set forth in claim 1, further comprising: a transverse transfer unit configured to support the first and second probes and configured to move the first and second probes along a first horizontal direction; a longitudinal transfer unit configured to support the transverse transfer unit and configured to move the first and second probes along a second horizontal direction orthogonal to the first horizontal direction; and a support unit configured to support both the transverse transfer unit and the longitudinal transfer unit, wherein the second probe is configured to measure the cladding of the second fuel rod of the nuclear fuel assembly using the second eddy current sensor while the second eddy current sensor moves in the second horizontal direction. 5. An apparatus for simultaneously measuring two fuel rods assembled in a nuclear fuel assembly, the apparatus comprising:a support unit;a longitudinal transfer unit disposed on the support unit and including first guide rails mounted on the longitudinal transfer unit;a transverse transfer unit disposed on the longitudinal transfer unit and including second guide rails mounted on the transverse transfer unit and a transfer table moving along the second guide rails, the transverse transfer unit configured to move in a first horizontal direction on the longitudinal transfer unit along the first guide rails;a frame disposed on the transfer table of the transverse transfer unit and configured to move in a second horizontal direction that is orthogonal to the first horizontal direction along with the transfer table;a cylinder configured to move vertically along the frame;a first probe disposed at a first side of the cylinder, the cylinder configured to move the first probe vertically, the first probe configured to measure a cladding of a first fuel rod that is at a periphery of the nuclear fuel assembly, the first probe including:a first lower plate mounted on the cylinder and configured to support the first probe,a fuel rod guide part disposed on the first lower plate and having a semi-circular channel shape formed in the vertical direction, the fuel rod guide part configured to move along the first fuel rod,a guide roller mounted above the fuel rod guide part disposed on the first lower plate and configured to guide the first probe along the first fuel rod,a first eddy current sensor mounted on the fuel rod guide part and configured to detect an amount of eddy current induced on the first fuel rod, andat least one supporting guide part disposed on the first lower plate side by side with the fuel rod guide part, the supporting guide part having a semi-circular channel shape and being configured to move along a neighboring fuel rod placed next to the first fuel rod; anda second probe disposed at a second side of the cylinder and configured to simultaneously measure a cladding of a second fuel rod that is disposed at an interior position of the nuclear fuel assembly not adjacent to the first fuel rod and including:a second lower plate mounted on the cylinder and configured to support the second probe,a strip disposed on the second lower plate, having a thin and long strip shape configured to be inserted between fuel rods in the nuclear fuel assembly; anda second eddy current sensor mounted on one end of the strip and configured to measure the cladding of the second fuel rod of the nuclear fuel assemblywherein the first probe is configured to measure the cladding of the first fuel rod of the nuclear fuel assembly using the first eddy current sensor while the first eddy current sensor moves in the vertical direction along the first fuel rod, andwherein the second probe is configured to measure the cladding of the second fuel rod of the nuclear fuel assembly using the second eddy current sensor while the second eddy current sensor moves in the first horizontal direction.
	claims	1. A method for treating a tumor of a patient in a treatment room with positively charged particles, comprising the steps of:delivering the positively charged particles from an accelerator along a beam transport path, the beam transport path redirectable as a function of time to yield a plurality of incident vectors of the positively charged particles into the treatment room;redirecting portions of the positively charged particles traveling along each of said plurality of incident vectors, with at least one output nozzle of said beam transport path, to the tumor;wherein a first vector, of said plurality of incident vectors, comprises a first direction entering the treatment room and intersecting the tumor,wherein a second vector, of said plurality of incident vectors, comprises a second direction entering the treatment room and not intersecting the tumor;said step of redirecting directing a first portion of the positively charged particles from the first vector to a first tumor treatment path entering a front of the tumor; andsaid step of redirecting directing a second portion of the positively charged particles from the second vector to a second tumor treatment path entering at least one of a side of the tumor and a back of the tumor relative to the front of the tumor. 2. The method of claim 1, further comprising the steps of:treating the tumor with: (1) the first tumor treatment path entering the front of the tumor and (2) the second tumor treatment path entering the side of the tumor without rotating a gantry supporting a section of said beam transport path. 3. The method of claim 2, further comprising a step of:treating the tumor on opposite sides of an interfering component of the patient without rotation of the patient and without transmitting the positively charge particles through the interfering component using the first portion of the positively charged particles intersecting the front of the tumor and the second portion of the positively charged particles intersecting the back of the tumor. 4. The method of claim 3, wherein the interfering component comprises a portion of a nervous system of the patient. 5. The method of claim 2, further comprising the steps of:limiting the first portion of the positively charged particles to a Bragg peak energy not reaching an interfering component when treating the tumor at a proximal side of the interfering component; andsaid step redirecting scanning the second portion of the positively charged particles to a treatment vector tangential to a distal side of the interfering component. 6. The method of claim 1, further comprising the step of:using a first beam path switching magnet to switch the beam transport path from a first statically positioned beamline, directing the first portion of the positively charged particles, to a second statically positioned beamline, directing the second portion of the positively charged particles, wherein said second statically positioned beamline comprises use of at least one beam turning magnet not used to turn said first statically positioned beamline. 7. The method of claim 6, further comprising the step of:within five seconds, treating the tumor using the first statically positioned beamline and the second statically positioned beamline. 8. The method of claim 6, further comprising the step of:using a second beam path switching magnet to switch to a third statically positioned beamline, wherein a third vector, of said plurality of incident vectors, comprises a third direction passing by the tumor without entering the tumor, said second direction and the third direction intersecting at an angle of greater than sixty degrees and less than eighty-five degrees as viewed in two-dimensions. 9. The method of claim 1, further comprising the step of:sequentially disconnecting said output nozzle from a first beamline of said beam transport path, moving said output nozzle, and connecting said output nozzle to a second beamline of said beam transport path. 10. The method of claim 1, wherein the first vector and the second vector do not intersect in an isocenter point about which a gantry supporting a section of the beam transport path rotates. 11. The method of claim 2, further comprising the step of:prior to said step of redirecting, using at least one fiducial marker and at least one fiducial detector to determine a relative position of the patient and the first vector. 12. The method of claim 11, further comprising the step of:transforming a doctor approved tumor irradiation plan using an isocenter point to an irradiation plan calibrated to at least one of the plurality of incident vectors. 13. The method of claim 11, further comprising the step of:determining an unobstructed path from said exit nozzle to the patient using said at least one fiducial marker and said at least one fiducial detector. 14. The method of claim 13, wherein the first vector maintains a distance of at least two centimeters from the second vector. 15. The method of claim 13, further comprising the step of:offsetting the tumor of the patient, relative to an isocenter of a gantry system configured to move said output nozzle, by at least five inches on a first axis and by at least five inches on a second axis, the second axis perpendicular to the first axis. 16. An apparatus for treating a tumor of a patient in a treatment room with positively charged particles, comprising:a synchrotron;a beam transport path configured to deliver the positively charged particles from said synchrotron, the beam transport path redirectable as a function of time to yield a plurality of incident vectors, each of said plurality of incident vectors directed into the treatment room; andat least one output nozzle configured to redirect portions of the positively charged particles traveling along each of said plurality of incident vectors to the tumor,wherein a first vector, of said plurality of incident vectors, comprises a first direction entering the treatment room and intersecting the tumor,wherein a second vector, of said plurality of incident vectors, comprises a second direction entering the treatment room and not intersecting the tumor,said at least one output nozzle configured to: (1) redirect a first portion of the positively charged particles from the first vector to a first tumor treatment path entering a front of the tumor and (2) redirect a second portion of the positively charged particles from the second vector to a second tumor treatment path entering a side of the tumor relative to the front of the tumor.
060884177	summary	BACKGROUND OF THE INVENTION Field of the Invention The invention relates to an apparatus for leak detection and leak location in a nuclear plant, in particular in a pipeline of a nuclear plant, having a collection line which is permeable to a substance to be detected and communicates with a pump and with a sensor for the substance, and in which the sensor is not suited to detecting the radioactivity of the substance. The invention also relates to a method for detecting and locating leaks in a nuclear plant, in particular in a pipeline of a nuclear plant, in which the concentration of a substance from the plant that has penetrated a collection line is measured. German Published, Non-Prosecuted Patent Application 24 31 907 corresponding to U.S. Pat. Ser. No. 3,977,233, discloses an apparatus for leakage detection and location (which is abbreviated as LEOS). That apparatus includes a collection line which is permeable to the substances to be detected. Communicating with the collection line is a pump, with which volumes of a transport medium, such as air, are pumped in succession through the collection line. Disposed at the end of the collection line is at least one sensor, which detects substances that have penetrated the collection line. A special construction of such a collection line is known from European Patent 0 175 219 B1. It has permeable points, which may be formed of sintered metal and are spaced apart from one another. The line is impermeable between those permeable points. U.S. Pat. No. 5,301,538 describes a further leak detecting and locating apparatus, which has at least two collection lines permeable to substances to be detected. The collection lines discharge into a common gas sensor, which in particular may be a sensor for radioactive radiation. In particular, there may be two gas sensors. A device for monitoring a line in which radioactive substances are carried, is known from Published Japanese Patent Application JP 59 166 986. That line is surrounded by a collection line of larger diameter, which communicates with a radioactivity detector. SUMMARY OF THE INVENTION It is accordingly an object of the invention to provide an apparatus and a method for leak detection and location, which overcome the hereinafore-mentioned disadvantages of the heretofore-known apparatuses and methods of this general type in such a way that a second, diverse evidence of leakage is possible. As a result, even more-reliable leakage detection and location are to be assured. With the foregoing and other objects in view there is provided, in accordance with the invention, an apparatus for detecting and locating leaks in a nuclear plant, in particular in a pipeline of a nuclear plant, comprising a collection line permeable to a substance to be detected; a pump communicating with the collection line; a sensor communicating with the collection line for sensing the substance, the sensor not suited to detecting radioactivity of the substance; and a detector communicating with the collection line for detecting radioactivity of the substance. This detector may be a gamma detector. In that case, not only the maximum concentration of a substance that has penetrated but also the maximum activity of the penetrating substance is determined and utilized for detecting and locating leaks. Thus two redundant apparatuses for leakage location are obtained. In accordance with another feature of the invention, there is provided a branch line which communicates with the detector and branches off upstream of the sensor. In accordance with a further feature of the invention, there is provided a suction pump associated with the detector. In accordance with an added feature of the invention, there is provided a supply container in which the detector is disposed. In accordance with an additional feature of the invention, there is provided a valve disposed upstream of the collection line. In accordance with yet another feature of the invention, the sensor determines a concentration of substances. In accordance with yet a further feature of the invention, there are provided openings which are located at intervals in the collection line and at which check valves are disposed. These check valves are constructed in such a way that they open if a predetermined pressure fails to be attained, but otherwise are closed. If the sensor line is closed at its entrance by a valve and a suction pump upstream of the radioactivity detector is turned on, these check valves open once the predetermined pressure fails to be attained. The location of the leak can be determined from the period of time that elapses between the opening of the check valves and the response of the detector for detecting the radioactivity, if the flow speed in the collection line is known. This advantageously provides two possibilities of leakage location, thereby assuring reliable results. With the objects of the invention in view there is also provided a method for detecting and locating leaks in a nuclear plant, in particular a pipeline of the nuclear plant, which comprises measuring concentration and radioactivity of a substance from a nuclear plant having penetrated a collection line. In accordance with another mode of the invention, if the flow speed in the collection line is known, the location of the leak is determined, for instance, from the period of time that has elapsed between a pressure surge in the collection line and a response of the detector for detecting radioactivity. In accordance with a concomitant mode of the invention, the pressure surge may in particular be brought about by the opening of at least one check valve. Other features which are considered as characteristic for the invention are set forth in the appended claims. Although the invention is illustrated and described herein as embodied in an apparatus and a method for leak detection, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
047987006	claims	1. In combination with a gas-cooled high temperature reactor having discrete absorber material elements for shutting down said reactor and a core filled with spherical fuel elements, a graphite side reflector comprising at least one nose-shaped projection protruding radially into the reactor core from said graphite side reflector, said at least one nose-shaped projection comprising: (a) at least one vertically disposed cavity adapted to receive said discrete absorber material elements, (b) a vertically disposed, continuous opening which forms a passageway for communication between said cavity and the core of the reactor, and (c) blocking means cooperatively engaged with said projection and positioned within said continuous opening for preventing direct communication between said cavity and the core of the reactor, said opening having a maximum width adjacent said cavity which is less than the minimum dimension of said discrete absorber elements in order to prevent passage of said elements into said continuous opening for said cavity. 2. The combination according to claim 1, wherein said blocking means comprises a graphite block cooperatively and freely engaged by correspondingly shaped portions of said projection and positioned transversely to said opening. 3. The combination according to claim 1, wherein said at least one nose-shaped projection comprises a plurality of graphite nose stones stacked one upon the other, said nose stones each including a vertically disposed continuous opening aligned with the vertically disposed continuous opening in adjacent nose stones. 4. The combination according to claim 1, comprising at least two nose-shaped projections uniformly positioned around the circumference of the reactor. 5. The combination according to claim 4, comprising four nose-shaped projections uniformly positioned around the circumference of the reactor in the form of opposing pairs aligned along a common axis. 6. The combination according to claim 1, wherein said vertically disposed , continuous opening extends from said cavity in said nose-shaped projection toward a center of said reactor core. 7. The combination according to claim 1, wherein said at least one nose-shaped projection comprises a plurality of grooves in the exterior surface thereof, wherein said continuous opening in the projection is a lateral extension of one of the exterior grooves toward said cavity. 8. The combination according to claim 1, wherein said continuous opening has a constant gap width. 9. The combination according to claim 1, wherein said continuous opening has a width which increases in dimension toward said core. 10. The combination according to claim 1, wherein said continuous opening has straight lateral surfaces. 11. The combination according to claim 1 wherein said continuous opening extends from said cavity in a direction away from the center portion of said core and comprises lateral curving surfaces.
052241360	claims	1. An apparatus for acquiring a tomographic projection set of an imaged object, the apparatus comprising: an x-ray generator for projecting a beam of x-rays through the imaged object at a plurality of angles about the imaged object gantry plane substantially perpendicular to a translation axis; an x-ray detector opposing the x-ray generator through the imaged object for receiving the x-ray beam at the plurality of angles to create a projection set; a table for supporting and translating the imaged object by a translation distance along a translation axis with the acquisition of the projection set during a first period, the translation being concurrent with the projections of the plurality of angles; a means for alternately sweeping the beam by a predetermined compliance distance along the translation axis in a first direction during the first period, and in a second direction along the translation axis but counter to the translation of the imaged object during a second period, wherein the compliance distance is limited to less than the translation distance and wherein the beam of x-rays is received by the x-ray detector throughout the sweeping of the beam by the compliance distance. 2. The apparatus as recited in claim 1 including additionally an exposure controller for controlling the exposure of the imaged object by the x-ray beam during the first period so that the exposure during the first period is greater than the x-ray exposure of the imaged object by the x-ray beam during a second period. 3. The apparatus as recited in claim 2 wherein the exposure controller reduces the intensity of the x-ray beam during the second period. 4. The apparatus as recited in claim 1 wherein the means for alternatively sweeping sweeps the x-ray beam during a first portion of the first period so as to maintain the beam centered on a predetermined volume element on the translation axis in the imaged object within the predetermined compliance distance and stops the sweeping of the x-ray beam during a second portion of the first period at the limit of the predetermined compliance distance. 5. The apparatus as recited in claim 4 wherein the first portion is divided equally between the start and end of the first period. 6. The apparatus as recited in claim 1 wherein the means for alternatively sweeping, sweeps of the x-ray beam during the first period so as to maintain a constant angular motion of the beam during the first period. 7. The apparatus recited in claim 1 wherein the means for alternatively sweeping comprises a collimator positioned between the x-ray generator and the imaged object, the collimator having an aperture movable along the translation axis. 8. The apparatus recited in claim 1 wherein the means for alternatively sweeping comprises an x-ray source having a focal point movable along the translation axis and collimator having a aperture movable along the translation axis.
051401657	claims	1. A vessel for solidifying radioactive waste pellets comprising: a vessel body; an inner lid mounted within said vessel body and fixedly secured to an upper portion of said vessel body, said inner lid having an opening formed at a generally central portion thereof; and means for preventing the pellets from floating fixedly secured at one end thereof to said inner lid and extending into said opening to define therebetween gaps allowing the passage of a solidifying material in the state of a liquid or a slurry therethrough but preventing the passage of the radioactive waste pellets therethrough, said pellet float prevention means, when receiving a downward urging force, being bent downward to enlarge the gaps for allowing the radioactive waste pellets to pass therethrough, and said pellet float prevention means being returned by a resilient restoring force to its initial position when said downward urging force is released. (a) a vessel for solidifying radioactive waste pellets comprising (i) a vessel body; (ii) an inner lid mounted within said vessel body and fixedly secured to an upper portion of said vessel body, said inner lid having an opening formed at a generally central portion thereof; and (iii) means for preventing the pellets from floating fixedly secured at one end thereof to said inner lid and extending into said opening to define therebetween gaps allowing the passage of a solidifying material in the state of a liquid or a slurry therethrough but preventing the passage of the radioactive waste pellets therethrough, said pellet float prevention means, when receiving a downward urging force, being bent downward to enlarge the gaps for allowing the radioactive waste pellets to pass therethrough, and said pellet float prevention means being returned by a resilient restoring force to its initial position when said downward urging force is released; and (b) a charge pipe for insertion through said opening of said inner lid so as to charge the radioactive waste pellets into said vessel body, a distal end of said charge pipe which is adapted to be inserted through said opening being generally rounded. 2. A vessel according to claim 1, wherein said pellet float prevention means comprises a plurality of coil springs fixedly secured to said inner lid in a radial manner, some of said plurality of coil spring extending to an area close to the center of said opening in said inner lid. 3. A vessel according to claim 1, wherein said pellet float prevention means comprises straight resilient wires fixedly secured to said inner lid in a radial manner, some of said plurality of resilient wires extending to an area close to the center of said opening in said inner lid. 4. A vessel according to claim 2, wherein said plurality of coil springs are extended in such a manner that the axis of each of said coil springs is displaced a predetermined angle from the center of said opening in said inner lid. 5. A vessel according to claim 3, wherein said plurality of straight resilient wires are extended in such a manner that the axis of each of said resilient wires is displaced a predetermined angle from the center of said opening in said inner lid. 6. A vessel according to claim 1, wherein said pellet float prevention means comprises resilient elements fixedly secured to said inner lid, and bar-like elements fixedly secured to said resilient elements and normally urged by a resilient force of said resilient elements to a generally horizontal position, said resilient elements of said pellet float prevention means being arranged in a radial manner, and said bar-like elements having one end which is held against an inner peripheral surface of said opening of said inner lid in said generally horizontal position of said bar-like elements so as to prevent upward movement of said bar-like elements beyond said generally horizontal position. 7. A vessel according to claim 1, wherein said pellet float prevention means comprises base elements fixedly secured to a lower surface of said inner lid, bar-like elements hingedly connected to said base elements, and resilient elements normally urging said bar-like elements to a generally horizontal position, and said bar-like elements having a stop surface which is held against said base elements in said generally horizontal position of said bar-like elements so as to prevent an upward movement of said bar-like elements beyond said generally horizontal position. 8. A vessel according to claim 1, wherein said pellet float prevention means comprises a pair of metal nets hingedly connected to a lower surface of said inner lid, and a pair of resilient elements which respectively urge normally said pair of metal nets to a generally horizontal position. 9. A vessel according to claim 1, wherein said inner lid has a plurality of air bleed holes formed therethrough. 10. A combination comprising: 11. A combination according to claim 10, wherein said pellet float prevention means comprises a plurality of coil springs fixedly secured to said inner lid in a radial manner, some of said plurality of coil springs extending to an area close to the center of said opening in said inner lid. 12. A combination according to claim 10, wherein said pellet float prevention means comprises straight resilient wires fixedly secured to said inner lid in a radial manner, some of said plurality of resilient wires extending to an area close to the center of said opening in said inner lid. 13. A combination according to claim 11, wherein said plurality of coil springs are extended in such a manner that the axis of each of said coil springs is displaced a predetermined angle from the center of said opening in said inner lid. 14. A combination according to claim 12, wherein said plurality of said straight resilient wires are extended in such a manner that the axis of each of said resilient wires is displaced a predetermined angle from the center of said opening in said inner lid.
056339011	description	DESCRIPTION OF THE PREFERRED EMBODIMENT The permanent pool cavity seal according to the invention is generally comprised of seal plate 10, inner seal ring 13, outer seal ring 14, J-shaped flexible ring 11, support ring 12, leveling screw support arm 15, leveling screw 16, and means for covering and sealing access hole 32 in seal plate 10. Seal plate 10 is an annular member preferably formed from stainless steel, which is 1.5 inches in thickness for withstanding the weight of the water and the impact of any fuel which may be dropped during the refueling operation. Seal plate 10 is formed from a plurality of arcuate plates such that they form an annular seal plate 10 when positioned adjacent to each other around reactor vessel 26. The arcuate plates are splice welded together before being welded respectively to support ring 12 and J-shaped flexible ring 11. Seal plate 10 is provided with a plurality of access holes 32 spaced around its circumference. Access holes 32 provide access to nuclear instruments positioned therebelow in the refueling pool cavity 21 between reactor vessel 26 and concrete shielding structure 25 and allow circulation of air from beneath reactor vessel 26 during normal reactor operations. Each access hole 32 in seal plate 10 has two annular concentrically disposed grooves 30, each containing an O-ring 31 to provide the seal around its circumference. Each access hole cover 28 is secured in its associated access hole 32 by bolts 35 and has a hole 29 and hole plug 33 which is fastened by bolts and which provides means to check the seal condition before the refueling cavity is flooded. Seal plate 10 is provided with an annular support ring 12 and an annular J-shaped flexible ring 11 that extends axially from the seal plate. Support ring 12 is preferably formed from the same material as seal plate 12. Support ring 10 is formed from a plurality of arcuate plates such that they form the annular support ring 12 when positioned adjacent to each other on the refueling pool floor 23. The arcuate plates are splice welded together before being welded to seal plate 10. J-shaped flexible ring 11 must also be structurally flexible enough to accomodate the radial and axial thermal expansion or contraction of the reactor vessel 26. J-shaped flexible ring 11 is preferably formed from stainless steel which has 0.1 to 0.2 inches thickness. J-shaped flexible ring 11 is formed form a plurality of arcuate plates such that they form an annular J-shaped flexible ring 11 when positioned adjacent to each other on the reactor vessel flange 27. The arcuate plates are splice welded together before being welded to seal plate 10. Seal plate 10 is welded respectively to support ring 12 and J-shaped flexible ring 11 before in-place installation. Outer seal ring 14 and inner seal ring 13 are preferably formed from the same material as seal plate 10. Outer seal ring 14 and inner seal ring 13 are formed from a plurality of arcuate plates that form the outer seal ring 14 and inner seal ring 13 respectively, when positioned adjacent to each other. The arcuate plates forming the outer and inner seal rings are splice welded together before being attached by bolts 36 and sealingly welded to reactor vessel flange 27 and embedded ring 24 in refueling pool floor 23, respectively. A plurality of support arms 15 underneath the seal plate 10 are provided to support seal plate 10. Each support arm 15 extending from the refueling pool cavity wall 25 toward the seal plate 10 adjacent the J-shaped flexible seal 11 may have at least a leveling screw 16 to adjust the level of seal plate 10.
	abstract	Certain aspects pertain to Fourier ptychographic imaging systems, devices, and methods that implement an embedded pupil function recovery.
	claims	1. A concrete cask comprising:an inner shell made from metal;an outer shell made from metal;a shielding body composed of concrete and provided between said inner shell and said outer shell;heat transfer fins provided between said inner shell and said outer shell; andan accommodation portion formed inside said inner shell for accommodating a radioactive substance therein thereby being kept from the outside of the cask, whereinsaid concrete includes portland cement, andsaid heat transfer fins each has an inner shell-side and an outer shell-side and is configured such that said inner shell-side is in contact with the inner shell and the outer shell-side is formed with at least a portion that is not in contact with the outer shell; orsuch that said outer shell-side is in contact with the outer shell and the inner shell-side is formed with at least a portion that is not in contact with the inner shell. 2. The concrete cask according to claim 1, comprising at least a first heat transfer fin provided in contact with said outer shell and a second heat transfer fin provided in contact with said inner shell, the first heat transfer fin and the second heat transfer fin being provided so as to overlap each other and so that there is a clearance between said first and said second heat transfer fins in said overlap portion. 3. The concrete cask according to claim 2, wherein when the length of the overlap portion of said first and said second heat transfer fins is denoted by w1 and the clearance between said first and said second heat transfer fins in the overlap portion is denoted by a1, then the following relation is satisfied:a1·(2·λc·w1·Lc)/(λf·t),where λc: thermal conductivity of the concrete (W/m·K);Lc: thickness of the concrete shielding body (m);λf: thermal conductivity of the heat transfer fins (W/m·K);t: thickness of the heat transfer fins (m). 4. The concrete cask according to claim 1, wherein the side of said heat transfer fins that forms said separation portion is formed to have substantially an L-like shape so as to be provided with an opposite surface facing said inner shell or said outer shell. 5. The concrete cask according to claim 4, wherein if the separation clearance of said separation portion is denoted by a2, the following relationship is satisfied:a2·(2·λc·w2·Lc)/(λf·t),where λc: thermal conductivity of the concrete (W/m·K);Lc: thickness of the concrete shielding body (m);λf: thermal conductivity of the heat transfer fins (W/m·K);t: thickness of the heat transfer fins (m);w2: length of said opposite surface in the width direction (m). 6. The concrete cask according to claim 1, wherein said heat transfer fins are formed to have substantially an I-like shape, when viewed from the shell end. 7. The concrete cask according to claim 1, wherein said separation portion is composed so as to separate completely the heat transfer fins and the inner shell or outer shell. 8. The concrete cask according to claim 1, wherein said heat transfer fins are disposed at an angle to the radial direction of said shielding body. 9. The concrete cask according to claim 1, wherein openings are formed in said heat transfer fins. 10. The concrete cask according to claim 1, wherein said shielding body comprises a metal material in at least one shape of grains, particles, or fibers. 11. The concrete cask according to claim 1, wherein said shielding body contains 15 mass % or more of hydroxide retaining water as crystals with a melting point and decomposition temperature higher than 100° C. 12. The concrete cask according to claim 1, wherein said shielding body is sealed so as to be shielded from outside air. 13. The concrete cask according to claim 1, wherein said radioactive substance is contained in a canister which includes a body and a lid, and said canister is placed in said accommodation portion. 14. A concrete cask comprising:an inner shell made from metal;an outer shell made from metal;a shielding body composed of concrete and provided between said inner shell and said outer shell; andan accommodation portion for accommodating a radioactive substance inside said inner shell thereby being kept from the outside of the cask, whereinsaid shielding body is composed of said concrete including portland cement and a metal material that has a high thermal conductivity, wherein said cask has heat fins located between said inner shell and said outer shell. 15. The concrete cask according to claim 14, wherein the thermal conductivity of the shielding body is 4 (W/m·K) or more. 16. The concrete cask according to claim 14, wherein said shielding body comprises a metal material in at least one shape of grains, particles, or fibers. 17. The concrete cask according to claim 14, wherein said shielding body contains 15 mass % or more of hydroxide retaining water as crystals with a melting point and decomposition temperature higher than 100° C. 18. The concrete cask according to claim 17, wherein said hydroxide shows poor solubility or insolubility in water. 19. The concrete cask according to claim 14, wherein said radioactive substance is contained in a canister which includes a body and a lid, and said canister is placed in said accommodation portion.
	summary
042784980	summary	The invention relates to an earthquake-proof mounting support control rod drives of nuclear reactors, preferably pressurized-water reactors, including a reactor pressure vessel with a convex vessel cover and also control rods and control rod drive shafts which are coupled thereto and are mounted so as to be movable in axial direction thereof within tubular drive housings extending pressure-tightly through the pressure vessel cover and sealed against the outside, the drive housings including control rod drive stub tubes forming respective feed-through passageways and pressure tube sealingly connected thereto, such as by a flange connection, especially, the control rod drive stub tubes extending with different stub tube lengths above the spherical vessel cover. From the journal "Kerntechnik, Isotopentechnik und Chemie," 1968, No. 4, pages 217 to 225, especially FIG. 9 (see also the associated reprint pages 1 as well as 7 to 9), control rod drives of the hereinaforementioned type have become known heretofore. The problem underlying the invention is to construct these heretofore known control rod drives with respect to earthquake safety in such a manner that undesirable earthquake vibrations of the control rod drives, including the stub tubes thereof are reliably avoided. A basic beginning is from the realization that certain groups of control rod drives with the same stub tube length, if struck in the resonance-frequency range, can be excited to especially heavy vibrations by the foundation shocks due to an earthquake, whereas others, which are outside the resonance frequency range, are not so excitable. This involves especially transversal vibrations, longitudinal vibrations being only of secondary importance. It is accordingly an object of the invention to provide an earthquake-proof mounting support which will take such transversal vibrations into account. With the foregoing and other objects in view, there is provided in accordance with the invention, an earthquake-proof mounting support of the type hereinbefore defined which offers a solution for the problem that is presented providing that the upper ends of the pressure tubes are flexibly connected to each other by grid bars of a support grid. Thus, use is made of the fact that the control rod drives individually or in groups vibrate differently with respect to frequency, amplitude and direction in the event of an earthquake or of another phenomenon initiating vibrations. Mutual cancellation of the undesired vibration is thus achieved by means of the invention, or at least a reduction to smaller amplitudes is achieved by mutual attenuation. Through the use of grid link bars, unimpeded thermal movement of the drive housings in the axial direction thereof without mutual interference is achieved whereas, in the event of excitation in transversal direction due to an earthquake, the vibrations are cancelled due to coupling. In accordance with another feature of the invention, the support grid comprises two subgrids respectively disposed in a lower and an upper grid plane. The vibration suppression is thereby even more effective, and the grid stiffness in the transversal direction is improved. In accordance with a further feature of the invention, the grid bars of the one grid plane are disposed in rotated relationship to the grid bar direction of the other grid plane. By the term grid, there is understood herein that, in one plane, there are at least two different grid bar directions. The grid bars can therefore be disposed in rectangular, square, rhombic or zig-zag configuration, wherein the hereinaforementioned rotation of the grid direction from the one to the next plane (statically defined truss structure) is especially advantageous. This structure is then stiff or rigid not only in two principal directions of the one grid, but also in other vibration directions which form an angle therewith. In accordance with an added feature of the invention, one subgrid is disposed in the form of a rectangular raster or screen, especially a square screen, and the other subgrid is formed of diagonal bars, the joints of which lie approximately in a projection of the corners of the one subgrid onto the other subgrid. The square raster or screen for the one subgrid represents the preferred embodiment since, in most cases, also, the control rod drives and the pressure tubes thereof are disposed in the form of such a raster or screen. In accordance with an additional feature of the invention, the grid bars are divided into halves, and the two grid bar halves are connected together by turnbuckle means. On the one hand, this affords equalization of tolerances in the assembly and, on the other hand, vibration-damping coupling between respective adjacent tubes can be made strong enough without adverse effect on the flexible connection for the relative thermal expansions. In accordance with another embodiment of the invention the earthquake-proof mounting support when applied to reactor pressure vessels wherein the control rod drives, including drive housings and associated drive shafts, extend pressure-tightly through a spherical bottom wall of the pressure vessel and are disposed with the pressure tubes thereof protruding downwardly and/or in which the free axial length of the drive housings of the control rod drives are approximately equal to one another, preferably for boiling-water reactors, the pressure tubes are articulatingly connected to each other in the vicinity of the lower ends thereof by the grid bars of the support grid in such a manner that the free axial lengths of the drive housings, measured from the outside of the spherical bottom wall or the outside of the spherical cover, respectively, to the grid joint, are different as viewed over the cross section of the support grid. Other features which are considered as characteristic for the invention are set forth in the appended claims. Although the invention is illustrated and described herein as embodied in an earthquake-proof mounting support for control-rod drives of nuclear reactors, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
051195984	abstract	A method of constructing a top slab to provide a containment roof over a nuclear-power generating building, in particular, a method for utilizing overhead spaces bounded by a wall of the containment building and a shielding wall of the pressure vessel building, wherein the sequential steps involve; erecting a plurality of paired support columns on tops of the wall and of the shielding wall; building upper structural components across said paired support columns; installing a slab liner equipped with slab anchors beneath said lower structural components by suitable joining means; constucting a reinforcing network above said lower structural components; encasing said lower structural components and said reinforcing network; and pouring concrete over the slab liner to a suitable depth.
	abstract	A system for particle beam therapy has an adjustable gantry for beam delivery to a patient site. The gantry has a beam coupling section, a first beam bending section with beam deflection and/or focusing magnets. A beam transport section receiving the particle beam from the first beam bending section and guiding the particle beam to a second beam bending section. The beam exits at a window of a beam nozzle. A patient table/chair is rotatable in the horizontal plane or in a plane being parallel to the horizontal plane and optionally being adjustable vertically. The gantry is supported by a tilting mechanism allowing the gantry to be tilted vertically by an angle Φ1ε[−90°; +90°]. A rotation mechanism is disposed in a way that the second beam bending section and the beam nozzle are rotatable by an angle Φ2ε[−180°; +180°] around a direction given by the angle Φ1.
	description	The invention relates to the field of radiography. More particularly, the invention relates to an anti-scatter device. The invention further relates to a method of manufacturing the anti-scatter device. The invention further relates to a use of the anti-scatter device. Anti-scatter devices are typically removable devices that are attached onto a detecting end of an x-ray imaging device. The anti-scatter device, typically situated between the object and the x-ray detection device, is advantageously used in the removal of background haze or loss of contrast in the generated x-ray image that are caused by scattered radiation. These anti-scatter devices are designed to selectively permit the passage of primary and attenuated x-rays passing through an object during an imaging procedure and absorbs or prevents the passage of scattered radiation. A typical anti-scatter device comprises an array of x-ray absorbing material, each separated by a spacer material. The array of x-ray absorbing material, which is typically made of lead, is oriented at specific angles that are specific to a particular x-ray imaging system. The spacer material is arranged to provide mechanical stability to the anti-scatter grid as well as to prevent changes in the orientation of the x-ray absorbing material. However, with the use of anti-scatter devices, the average power levels of the x-rays have to be increased. This is because of the increased absorption of x-rays by the x-ray absorbing material. Subsequently, the dosage of x-rays that a patient receives during an imaging procedure is increased with the use of the anti-scatter grid. An embodiment of an anti-scatter device for radiography is disclosed in U.S. Pat. No. 6,594,342 B2. The anti-scatter device disclosed includes a plurality of generally radiation absorbing elements and a plurality of generally non-radiation absorbing elements. The plurality of generally non-radiation absorbing elements includes a plurality of voids and desirably that the non-radiation absorbing elements include an epoxy or a polymeric material and a plurality of hollow microspheres. The document further discloses an apparatus for forming the anti-scatter device in which the apparatus includes a pivoting arm and a surface for use in aligning a plurality of spaced-apart and generally radiation absorbing elements relative to a radiation source. Using the technique as disclosed, it becomes difficult and expensive to manufacture the anti-scatter device. This is because of special requirements of including a plurality of microspheres in the generally non-radiation absorbing material. Furthermore, it is possible that some or all of these microspheres will degrade with time and cause varied absorption and non-absorption of scattered radiation in the anti-scatter device. This results in reduction in the resolution of the image generated. It is, therefore, an object of the invention to provide an anti-scatter device that provides improved resolution of an image. A first aspect of the invention provides an exemplary anti-scatter device for suppressing scattered radiation is disclosed. As explained hereinabove, the use of the term radiation in the present context should be construed as being x-rays. The anti-scatter device comprises a plurality of x-ray absorbing layers. The anti-scatter device further comprises a plurality of spacer layers, such that each spacer layer is arranged between any two of the plurality of x-ray absorbing layers in order to hold each of the plurality of x-ray absorbing layers in a pre-defined orientation. Furthermore, each of the plurality of spacer layers comprises a plurality of unsealed voids to reduce the absorption of x-rays incident on at least a portion on each of the spacer layers. Detailed information on the predefined orientation of the spacer layers with respect to the x-ray absorbing layers can be found in prior art document, U.S. Pat. No. 6,594,342 B2, which is herein incorporated by reference. The plurality of unsealed voids on each of plurality of spacer layers may advantageously be used to further reduce the absorption of x-rays that are incident on each of the spacer layers, thereby facilitating proper detection of x-rays. A further advantage of having the plurality of unsealed voids on the spacer layers is that the dosage of x-rays that an object, for example a patient undergoing an imaging procedure is reduced. In other words, for a given dosage of x-rays that an object receives, using such a device as embodied herein facilitates the generation of an image with improved resolution. Furthermore, the device also facilitates a reduction in the amount of x-ray dosage received by the patient. This is because in an imaging apparatus using an anti-scatter device, the average x-ray power levels are higher than in a procedure where the anti-scatter device is not used. However, as will be appreciated by a person skilled in the art, anti-scatter devices are necessary to reduce the effects of scattered radiation that tend to reduce the resolution of the generated image. In a further embodiment of the invention, the spacer layer in the anti-scatter device comprises a fiber material. Fiber material may advantageously be used due to ease of forming the plurality of voids, particularly when mechanical and/or optical means are used to form the plurality of voids and also because of ease with which the composite strips may be formed. For example, in one implementation, the fiber material could be a plant fiber material such as cotton paper. In accordance with a further aspect of the invention, a method of manufacturing an anti-scatter device for suppressing scattered radiation is disclosed. The method comprises applying a first bonding material on a first surface of a spacer material. The method also comprises attaching at least a layer of x-ray absorbing material onto a second surface of the spacer material via a second bonding material to form a composite foil. The method also comprises forming a plurality of unsealed voids on at least a portion on each of the spacer material. The method further comprises forming a plurality of composite strips from the composite foil and stacking each composite strip over another of the composite strip from the plurality of composite strips. The method further comprises applying heat on the stacked composite strips to activate the first bonding material to bond the plurality of composite strips in a pre-defined orientation. One advantage of the anti-scatter device is that it is inexpensive to manufacture because it involves very little modification to existing processes of manufacturing anti-scatter grids that are currently being made while providing for improved resolution of the generated image when used in conjunction with a radiographic imaging apparatus. The spacer material is typically less absorbent to x-rays than the x-ray absorbent material. As described previously, the spacer material is used in between each of the plurality of x-ray absorbent material to hold the x-ray absorbent material in a desired orientation. The spacer material is typically a fiber material. For example, in certain implementations, the spacer material may, for example, be a type of paper or paper-like material. However, appropriate material such as plastic or any other material that is generally non-absorbent to x-rays, may be substituted and should be considered to be within the scope of the invention. Other desired properties of the spacer material, apart from the ability to absorb as little x-rays as possible is to be able to provide mechanical stability to the device, and to be non-degradable over time. The first bonding material is applied to the first surface of the spacer material. For example, shellac glue may be used as the first bonding material. The first bonding material is chosen such that it can be thermally activated at any desired point in time. The x-ray absorbing material is attached to the second surface of the spacer material using the second bonding material. The x-ray absorbing material is arranged to absorb any scattered radiation i.e., any attenuated x-rays that does not contribute to generation of a proper image. It must be noted that when x-rays pass through an object, most of the x-rays get attenuated and pass through the object along the same direction of incidence. However, some of the x-rays, during passage through the object, are subjected to a change in direction due to scattering. In certain instances, the energy of the x-rays may be decreased in energy. These are termed as scattered radiation, which is a form of secondary radiation. The arrangement of the spacer layer having the first bonding material and the second bonding material on either sides and the x-ray absorbing layer affixed to the spacer layer via the second bonding material is called the composite foil. Before the composite foil is formed, a plurality of unsealed voids is formed on the spacer layer. It must be noted that the plurality of unsealed voids may be formed on the spacer layer at any point in time prior to the formation of the composite foil. While the layer of spacer material generally is non-absorbent to radiation, there will be some amount of x-ray absorption by the spacer material. The formation of the unsealed voids on each layer of the spacer material further reduces the absorption of x-rays by the spacer material. The composite foil is then cut into a plurality of composite strips. Once the composite strips are formed, they are stacked one on top of the other. It should be noted that, once the stacking is done, the x-ray absorbing layer of each of the composite strip would be in contact with the first bonding material of an adjacent composite strip. Furthermore, it should be evident that, notwithstanding the first and the second bonding material, each layer of x-ray absorbing material is essentially sandwiched between two layers of the spacer material and vice versa. As described hereinabove, the function of each layer of the spacer material includes allowing the passage of primary and attenuated x-rays, providing mechanical stability to the device as well as holding each of the layers of x-ray absorbing materials in a specified orientation. Once the stack is formed, heat is applied on the stack to activate the first bonding material due to which, each of the composite strips in the stack bonds with its adjacent composite strip, thereby forming the device. In a further embodiment of the invention, the method comprises forming the plurality of the unsealed voids on the spacer material prior to applying the first bonding material. An advantage of forming the plurality of voids on the spacer material in this manner is that easy handling of the spacer material is facilitated. In a further embodiment of the invention, the method comprises forming the plurality of voids on the spacer material prior to forming the composite foil, but after the application of the first bonding material. An advantage of forming the plurality of voids on the spacer layer after application of the first bonding material but before the formation of the composite foil is that it eliminates protrusions of the first bonding material in the spacer material at an interface with the x-ray absorbing material. In a further embodiment of the invention, the method comprises forming the plurality of the unsealed voids via at least one of a mechanical means, a chemical means or an optical means. In a certain implementation, the mechanical means may comprise a device arranged to punch holes in the spacer material. In other implementations, the mechanical means may comprise a drilling device or a sawing device. In a certain other implementation, chemical means may be employed to form the plurality of voids on the spacer material using etching techniques commonly known in the art. In a certain other implementation, the plurality of voids may also be formed on the spacer material using optical means such as by the use of high intensity lasers. It should be noted that the choice of mechanical, chemical or optical means to form the plurality of holes depends on the size, shape of the unsealed voids that are required to be formed, as well as on the spacer material. An advantage of forming the unsealed voids on the spacer material is that it allows for better control during the formation of the voids. Also, in certain implementations, the unsealed voids may be formed in a manner that allows for different sized voids to be present at different spots along the spacer material depending on requirements. In accordance with a further aspect of the present invention, an exemplary method of use of an anti-scatter device for suppressing scattered radiation in a data acquisition device is disclosed. The method involves providing the anti-scatter device for attachment on a detecting surface of the data acquisition apparatus such that the detecting surface is arranged to receive via the device at least a portion of x-rays emitted. The anti-scatter device comprises a plurality of x-ray absorbing layers arranged in a pre-defined orientation and a plurality of spacer layers such that each spacer layer is arranged between any two of the plurality of x-ray absorbing layers in order to hold the plurality of x-ray absorbing layer in the pre-defined orientation. Furthermore, each spacer layer comprises a plurality of voids arranged to reduce absorption of x-rays incident on at least a portion on each of the plurality of spacer layers. Turning now to the drawings and referring first to FIG. 1, an exemplary arrangement of a composite foil 100 that constitute and form an anti-scatter device for selectively passing x-rays is illustrated. The composite foil 100 comprises a layer of x-ray absorbing material 110, a layer of spacer material 120, a layer of a first bonding material 130 and a layer of a second bonding material 140. Furthermore, as stated previously, the layer of spacer material 120 comprises a plurality of voids, generally represented by reference numeral 150. The layer of x-ray absorbing material 110 may typically constitute lead. However, with advancements in technology, any suitable x-ray absorbing material may be substituted in lieu of lead to achieve a similar functionality and that such substitution should be construed as being within the scope of the invention as described herein. In certain other implementations, the layer of x-ray absorbing material 110 may be constituted from a combination of two or more x-ray absorbing materials as well. While in the presently illustrated figure, the plurality of voids 150 are shown as being oriented along a specific axis of the layer of spacer material 120, i.e., along the wider surface of the layer of the spacer material 120, it should be noted that in certain other implementations of the invention, the plurality of voids 150 may be situated along the any other planar orientation of the layer of spacer material 120. In other words, the plurality of voids 150 may be formed along a width of the layer of spacer material 120. However, for all discussions herein below, the former arrangement of the plurality of voids 150 shall be considered. Detailed discussion on the plurality of voids shall be presented in the sections that follow herein below. The first bonding material 130 has the property that after it has been applied, it can be thermally activated at any later point in time. An example of such a bonding material is shellac glue. In one exemplary embodiment of the invention, the first bonding material 130 is applied to one surface of the layer of spacer material 120, while a second bonding material 140 is applied to another, opposite, surface of the layer of the spacer material 120. The second bonding material 140 is arranged to attach the layer of x-ray absorbing material 110 to the layer of spacer material 120. The second bonding material 140 may not have the property that lets it to be activated at a later point in time. The purpose of the second bonding material 140 is to firmly attach the layers of x-ray absorbing material 110 and the spacer material 120 and to hold the two layers (110, 120) in a specific orientation with respect to each other. An example for the choice of the second bonding material may be epoxy glue. Preferably, the first bonding material 130 and the second bonding material 140 should be capable of absorbing as little x-rays as possible. It should be noted that, the layers of x-ray absorbing material 110 and spacer material 120 would typically be in the form of foils having respective thicknesses. Therefore, once these aforementioned layers are arranged together, the result is the composite foil 100 having an exposed layer of the first bonding material 130 on one side, the layer of the spacer material 120, the layer of second bonding material 140 and a layer of the x-ray absorbing material 110 having an exposed surface on an other side of the composite foil. The plurality of voids 150 can be made in a variety of ways and in a variety of shapes and sizes. As will be appreciated by a person skilled in the art, the material of the spacer layer would play a significant role in determining how the plurality of voids are to be formed and by using what means. One desirable property of the spacer layer is that it should provide sufficient mechanical stability to the anti-scatter device and also be capable of holding the layers of x-ray absorbing material in a desired and pre-determined orientation. This further means that the spacer layer should be capable of not degenerating over time causing an alteration in the orientation of the layers of the x-ray absorbing material. The plurality of unsealed voids 150 may be formed by chemical means, mechanical means or optical means, and in certain instances, a combination of one or more of the aforementioned means. For example, when the spacer layer comprises a fiber material, such as cotton paper, mechanical means provide an easy way of forming the plurality of unsealed voids 150. The mechanical means could include a contraption that performs in a manner such as a paper-punching machine, having the desired depth of punch and the shape of punch. The contraption could, further, be configured to suit different thickness and type of spacer material as desired. In yet another implementation, the plurality of unsealed voids 150 may be formed by chemical means, such as selective chemical etching to form the desired shape and size of the voids. By suitably controlling the exposure of the spacer material to different kinds of solvents or gases, the shape and size of the voids can be controlled. In certain other implementation, using optical means such as lasers may form the plurality of unsealed voids 150. Using lasers has a good advantage that the accuracy of the plurality of voids and the exact geometry of the voids can be easily controlled and adjusted. Typically, when lasers are used to form the voids, it is controlled by means of a microprocessor that can be dynamically programmed to form various sizes and shapes of voids or can be pre-programmed for a specific requirement. While the sections herein above discussed in detail about the formation of the plurality of unsealed voids, it should also be noted that the layer of spacer material could, in certain implementations, comprise multiple slices. These slices, when properly and accurately arranged, may leave voids in between each of the slice thereby forming a plurality of voids in the layer of spacer material. Returning back to the discussion of FIG. 1, the composite foil 100, thus formed, is then cut into a plurality of composite strips, such that each composite strip has the same cross sectional layers as that of the composite foil. FIG. 2 illustrates an exemplary stack that forms the anti-scatter device 200. The anti-scatter device 200 comprises a plurality of composite strips 210, each composite strip generally represented by reference numeral 210. As will be known from previous discussion, each composite strip will include a layer of x-ray absorbing material 215, a layer of spacer material 230, a first bonding material 220 and a second bonding material 240. As will be evident from FIG. 2, the layer of the first bonding material 220 in a particular composite strip 210 will be in contact with the layer of x-ray absorbing material 215 on another composite strip 210 above it. In this way, by the addition of composite strips 210 to the stack, a device for selectively passing x-rays and having a particular dimension can be formed, where each composite strip can be oriented at a specific angle of incidence of x-rays. It should be particularly noted that once the composite strips are placed in a specific orientation, the first bonding material 220 in each of the composite strips 210 is activated. Activation of the first bonding material 220 can be done in a variety of ways. For example, in certain implementation, when the first bonding material 220 is shellac glue, the first bonding material 220 may be activated by providing thermal energy to the stack of composite strips. The shellac glue gets activated, and each composite strip 210 gets stuck to the composite strip located above it and forms a rigid structure representing an anti-scatter device that can be used to selectively pass x-rays. It should be particularly noted that once the rigid structure is formed, the orientation of the composite strips may not be preferably changed. To elucidate the use of this stack, consider an exemplary x-ray imaging system 300 as illustrated in FIG. 3. The x-ray imaging system 300 includes an x-ray source 310, and an x-ray detector 320. These are mounted on a movable arm 330 to provide mobility of the source 310 and the detector 320 over any desired region. The imaging system 300 further includes a patient table 340. The x-ray detector 320 has mounted on it, an anti-scatter device 350. The anti-scatter device 350 is a detachable unit and is used essentially to remove of any background haze or loss of contrast in the generated x-ray image that are caused by scattered radiation. The anti-scatter device 350 is situated always between the x-ray detector 320 and an object 360 undergoing an imaging procedure and placed on the patient table 340. As mentioned previously, by employing an anti-scatter device in accordance with different aspects of the present technique, the x-ray dosage that a patient would receive during an imaging procedure is significantly reduced and as will be described in the sections herein below, the anti-scatter device embodied herein is also inexpensive. It is also worth noting, that the anti-scatter device is also typically enclosed or encapsulated to provide it with a rigid and strong outer casing. Using carbon fiber or carbon composites for encapsulation has an advantage that the anti-scatter device is transparent to x-rays and does not cause any distortion in the x-rays that pass through it. Furthermore, the distance between the x-ray source and the x-ray detector is typically constant. This is the reason that anti-scatter devices are almost always custom designed in accordance with the design specification for each specific x-ray imaging system. This is also why that the different layers of x-ray absorbing material and spacer material have to be oriented in a specific angle or direction during the formation of the anti-scatter device. This means that, a particular anti-scatter device designed for one particular model of an x-ray imaging system may not be used with similar or equal effect in a different x-ray imaging system. FIG. 4 illustrates one exemplary embodiment of a layer of spacer material 400 comprising a plurality of unsealed voids 450. As illustrated, the plurality of unsealed voids 450, circular in this case, are arranged along defined rows and columns. An advantage of having such an arrangement is the ease of forming the plurality of unsealed voids. FIGS. 5 through 7 illustrate different embodiments of a layer of spacer material 500, 600, 700 respectively, each having a particular pattern of the plurality of unsealed voids 550, 650 and 750 respectively. FIG. 5 illustrates the plurality of unsealed voids 550 that are circular but arranged in a staggered orientation. An advantage of such staggering is that more unsealed voids can be made on a given area of the spacer material 500. However, care should be taken to ensure that mechanical rigidity of the spacer material, and thereby that of the anti-scatter device is not compromised. FIG. 6 illustrates the embodiment of the spacer material 600 where the unsealed voids are elliptical in shape and arranged along a definite row and column arrangement. While not illustrated, it should be noted that the elliptical shaped unsealed voids could also be arranged in a staggered arrangement as illustrated in FIG. 5 for the case of circular unsealed voids. FIG. 7 illustrates an arrangement of rectangular shaped unsealed voids 750 on an exemplary embodiment of the spacer material 700. The advantage of the embodied arrangement is that there can be maximum utilization of space to provide the unsealed voids 750 on the spacer material 700. While the preceding FIGS. 4 through 7 illustrated various exemplary embodiments depicting various shapes and arrangements of the plurality of unsealed voids on the spacer material, it should be realized that these representations are not to be considered as limiting. In certain exemplary implementations, the spacer material may have a combination of one or more of the embodied shapes of the unsealed voids or may include certain shapes that are not illustrated herein. Such deviations to achieve similar effects as presented herein should be construed as being within the scope of the present invention. FIG. 8 illustrates an exemplary method of manufacturing an anti-scatter device. In the illustrated embodiment, the method involves applying the first bonding material on a first surface of a layer of the spacer material. The method also involves forming a plurality of unsealed voids on at least a portion of the spacer material. Further, the method involves attaching at least a layer of x-ray absorbing material onto a second surface of the layer of the spacer material via a second bonding material to form a composite foil. Furthermore, the method involves forming a plurality of composite strips from the composite foil and stacking each composite strip on top of another composite strip. Finally, the method involves applying heat (thermal energy) on each composite strip to activate the first bonding material to bond the plurality of composite strips in a predefined orientation to form the anti-scatter device. As discussed previously, in certain other embodiments, another exemplary method of manufacturing the anti-scatter device, as illustrated in FIG. 9, may comprise the step of forming the plurality of unsealed voids on at least a portion of the layer of the spacer material prior to applying the first bonding material on a first surface of the layer of the spacer material. The order in the described embodiments of the method of the current invention is not mandatory, a person skilled in the art may change the order of steps or perform steps concurrently using threading models, multi-processor systems or multiple processes without departing from the concept as intended by the current invention. It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word “comprising” does not exclude the presence of elements or steps other than those listed in a claim. The word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the system claims enumerating several means, several of these means can be embodied by one and the same item of computer readable software or hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
	claims	1. An apparatus for irradiating an object with a charged particle beam, the apparatus comprising: an object carrier for holding the object to be irradiated, the object carrier having a plurality of support elements for supporting the object, the plurality of support elements defining a surface to receive the object; wherein the plurality of support elements each have an elastic contact portion for supporting a separate part of the object, the elastic contact portions each having: (i) a primary force exerting toward the object to substantially maintain the contact portion in contact with the object while being irradiated; and (ii) a secondary force exerted on the contact portion that is small enough to prevent the contact portion from sticking below the object but large enough to stabilize the object under the influence of operational vibrations when the object is being irradiated. 2. The apparatus of claim 1 , wherein each support element comprises a cylindrical body with the contact portion extending from an end of it, the cylindrical body being moveably mounted in a cylindrical cavity with a spring acting on the body for providing the primary force, and the cylindrical body being in frictional contact with the cylindrical cavity for providing the secondary force. claim 1 3. The apparatus of claim 2 , wherein the cylindrical body has a central longitudinal axis, and the contact portion is eccentrically disposed relative to said central axis and projects toward the object. claim 2 4. The apparatus of claim 3 , wherein the cavity is defined in a support element housing. claim 3 5. The apparatus of claim 3 , wherein the cavity is formed from a bore in a carrier body that contains the plurality of support elements. claim 3 6. The apparatus of claim 1 , wherein the primary and secondary forces are suitable to maintain support contact and adequately resist operational vibrations over a predefined range of operational beam/object tilt angles. claim 1 7. A carrier for supporting a an object to be irradiated by a charged particle beam, the carrier comprising: a carrier body adjustable for tilting the object to a desired tilt angle relative to the beam; a plurality of support elements mounted to the carrier body, each support element having a resiliently moveable protrusion extending away from the carrier body with each protrusion being disposed to supportably contact a distinct part of the object; wherein the plurality of protrusions substantially remain in supportable contact with the object when it is being irradiated regardless of the tilt angle, wherein each protrusion is (i) resiliently strong enough to substantially maintain contact with the object and to sufficiently resist being displaced when subjected to operating vibrations, but (ii) resiliently weak enough so as not to push the object away from the other protrusions. 8. The carrier of claim 7 , wherein each support element includes: claim 7 a housing fixed to the carrier body, a member slidably mounted within the housing, the member being slidable to and away from the carrier body, the protrusion being disposed at a distal end of the member away from the carrier body, and a spring mounted within the housing and coupled to the member to provide the protrusion with at least part of its resilience. 9. The apparatus of claim 8 , wherein the spring applies to the member a force that is sufficient to maintain the protrusion against the object but small enough not to disengage the object from other protrusions, and the housing provides a frictional force against the member such that the member sufficiently resists displacement when subjected to operating vibrations. claim 8 10. The apparatus of claim 9 , wherein the object is a wafer to be carried on its underside, the underside being irregularly shaped. claim 9 11. The apparatus of claim 8 , wherein the housing and member have circular cross-sections. claim 8 12. The apparatus of claim 8 , wherein the protrusion is off-center from the central axis of the member in the direction of movement. claim 8 13. A particle optical apparatus comprising: a beam source; and an object carrier for operably receiving an object to be irradiated by a beam generated from thc beam source, the carrier including: (i) a carrier body adjustable to vary the tilt angle between the object and the beam over a range of operating angles, (ii) a plurality of support elements distributed on the carrier body to support an object, the support elements each including (1) a moveable member extending toward the object""s under surface, the member having a contact portion at its distal end away from the carrier body to supportably contact the object underside, wherein the plurality of contact portions collectively support the object, (2) a spring mounted to the member to push it against the object, and (3) a cavity structure in frictional contact with the member when the object is being carried, (iii) wherein the spring provides sufficient force to maintain its associated member in contact with the object but weak enough so as not to push the object off of other member contact portions, and the frictional contact being sufficient enough to resist operable vibration but small enough so that the member does not stick below the object after being depressed. 14. The apparatus of claim 13 , wherein the member functions as described in claim 17 over the range of operable tilt angles. claim 13 claim 17 15. The apparatus of claim 13 , wherein each support element further comprises a housing with a cavity that defines the cavity structure. claim 13 16. The apparatus of claim 15 , wherein the housing is a cylindrical structure with a cylindrical cavity for slidably receiving the member, which has a corresponding cylindrical shape. claim 15 17. The apparatus of claim 16 , wherein the contact portion is a pin extending out of the member at the distal end. claim 16 18. The apparatus of claim 17 , wherein the pin extends out from the cylindrical member from an off-center position to create a moment sufficient to generate the frictional contact between the member and the housing. claim 17
	claims	1. An apparatus for providing a signal indicative of a property of an earth formation, the apparatus comprising:a carrier configured to be conveyed through a borehole penetrating the earth formation;a neutron source disposed on the carrier and configured to emit neutrons into the earth formation;a radiation detector disposed on the carrier and configured to detect radiation from the earth formation due to interaction of emitted neutrons with the earth formation and to provide the signal indicative of the property; anda radiation detector neutron shield configured to shield the radiation detector from emitted neutrons that did not interact with the earth formation;wherein the radiation detector shield comprises a glass ceramic material having a plurality of nano-crystallites, each nano-crystallite in the plurality having a periodic crystal structure with a diameter or dimension that is less than 1000 nm that includes Li and/or Boron and a rare-earth element that have positions in the periodic crystal structure of each nano-crystallite. 2. The apparatus according to claim 1, wherein the radiation detector shield defines an opening configured to admit the radiation from the earth formation due to interaction of emitted neutrons with the earth formation. 3. The apparatus according to claim 1, further comprising:downhole electronics disposed on the carrier, coupled to the radiation detector and configured to process the signal indicative of the property to estimate the property; anda downhole electronics neutron shield configured to shield the downhole electronics from neutrons emitted by the neutron source;wherein the downhole electronics shield comprises a glass ceramic material having a plurality of nano-crystallites, each nano-crystallite in the plurality having a periodic crystal structure with a diameter or dimension that is less than 1000 nm and includes a rare-earth element that has positions in the periodic crystal structure of each nano-crystallite. 4. The apparatus according to claim 3, wherein at least one of the detector neutron shield and the downhole electronics neutron shield comprises a plurality of sections. 5. The apparatus according to claim 4, where the plurality of sections is connected by at least one of an adhesive and a mechanical fastener. 6. The apparatus according to claim 1, wherein the radiation detector comprises a neutron detector. 7. The apparatus according to claim 1, wherein the radiation detector comprises a gamma-ray detector. 8. The apparatus according to claim 1, wherein the property is porosity and/or density. 9. The apparatus according to claim 1, wherein the glass ceramic material comprises a composition of 10B, 6Li and rare-earth oxides, Sm2O3, Er2O3, Yb2O3, Nd2O3. 10. The apparatus according to claim 1, wherein the glass ceramic material comprises a composition of a natural B and rare-earth oxides, Sm2O3, Er2O3, Yb2O3, and Nd2O3. 11. The apparatus according to claim 1, wherein the glass ceramic material comprises a composition of 10B and rare-earth oxides, Sm2O3, Er2O3, Yb2O3, Nd2O3. 12. The apparatus according to claim 1, wherein the radiation detector neutron shield comprises an electrical penetration for electrically connecting an electrical conductor to the radiation detector. 13. The apparatus according to claim 1, wherein the carrier comprises at least one of a drill string, coiled tubing, a slickline and a wireline. 14. A method for providing a signal indicative of a property of an earth formation, the method comprising:conveying a carrier through a borehole penetrating the earth formation;emitting neutrons into the earth formation using a neutron source disposed on the carrier;detecting radiation from the earth formation due to interaction of emitted neutrons with the earth formation using a radiation detector configured to provide a signal indicative of the property;shielding the radiation detector from emitted neutrons that did not interact with the earth formation using a radiation detector neutron shield, wherein the radiation detector shield comprises a glass ceramic material having a plurality of nano-crystallites, each nano-crystallite in the plurality having a periodic crystal structure with a diameter or dimension that is less than 1000 nm that includes Li and/or B and a rare-earth element that have positions in the periodic crystal structure of each nano-crystallite. 15. The method according to claim 14, further comprising shielding downhole electronics disposed on the carrier and coupled to the radiation detector from neutrons emitted by the neutron source using a downhole electronics neutron shield, the downhole electronics neutron shield comprising a glass ceramic material having a glass ceramic material that includes a plurality of nano-crystallites, each nano-crystallite in the plurality having a periodic crystal structure with a diameter or dimension that is less than 1000 nm and includes a rare-earth element that has positions in the periodic crystal structure of each nano-crystallite. 16. The method according to claim 14, wherein the glass ceramic material comprises a composition of 10B, 6Li and rare-earth oxides, Sm2O3, Er2O3, Yb2O3, Nd2O3. 17. The method according to claim 14, wherein the glass ceramic material comprises a composition of a natural B and rare-earth oxides, Sm2O3, Er2O3, Yb2O3, and Nd2O3. 18. The method according to claim 14, wherein the glass ceramic material comprises a composition of 10B and rare-earth oxides, Sm2O3, Er2O3, Yb2O3, Nd2O3.
	description	Referring to FIG. 2, a membrane mask according to an embodiment of the present invention includes a silicon wafer 11, a membrane film 12 formed thereon and implemented by a first material having a relatively low atomic number, and a mask body pattern 13 formed thereon and implemented by a second material having a relatively high atomic number. The membrane film 12 has an implanted area 14 at the bottom of the mask body pattern 13 except for the opening in the mask body pattern 13. The implanted area 14 is formed by implanting or adding heavy atoms having an atomic number higher than the atomic number of the first material to the membrane film 12. The heavy atoms in the implanted area 14 have a function of scattering electron beams or absorbing X-rays in association with the mask body pattern 13. The area of the membrane film 12 other than the implanted area 14 has an inherent function for suitably passing therethrough electron beams or X-rays due to the absence of the heavy atoms therein. Examples of the first material in the membrane film 12 include silicon nitride (SiN), silicon carbide (SiC), boron nitride (BN), diamond (C) etc. The heavy atoms in the implanted area 14 of the membrane film 12 may be preferably selected from heavy metals, and more preferably selected from the heavy metals tabulated on he periodic table at the sixth period and the subsequent periods. Examples of the heavy metals include tungsten (W), tantalum (Ta), gold (Au), platinum (Pt), lead (Pb) etc. The implanted heavy atoms may include a plurality of heavy metals. The material for the mask body pattern 13 may be preferably selected from heavy metals or heavy alloys such as W. Ta, TaGe, TaReGe. The mask body pattern 13 may preferably include one or more of the heavy metals tabulated on the periodic table at the sixth period and the subsequent periods. Referring to FIGS. 3A to 3F, there is shown a fabrication process for fabricating a membrane mask according to an embodiment of the present invention. The membrane mask is used for an electron beam lithography, for example. In FIG. 3A, a silicon nitride film (SiN) 22 is deposited on the top surface of a silicon wafer 21 having a diameter of 200 mm by using a LPCVD (low pressure chemical vapor deposition) technique to a thickness of 100 nm (nanometers). It is to be noted that the thickness of the silicon nitride film 22 is preferably 150 nm or less. Subsequently, the silicon nitride film 22 is spin-coated with resin to form a resin film thereon, followed by patterning thereof using an electron beam lithographic technique to form a resist pattern 23, as shown in FIG. 3B. The resist pattern 23 has openings therein for implanted areas to be formed for scattering the electron beams. Thereafter, heavy metal ions such as tungsten or chrome ions are implanted into the silicon nitride film 22 by using a resist pattern 23 as a mask, thereby forming a heavy-metal-implanted area 24. The resist pattern 23 is then removed, as shown in FIG. 3C. A tungsten film 25 is deposited on the silicon nitride film 22 including the heavy-metal-implanted area 24 by using a sputtering or LPCVD technique to a thickness of about 10 nm, as shown in FIG. 3D. It is to be noted that the thickness of the tungsten film 25 is preferably 20 nm or less. Subsequently, the tungsten film 25 is spin-coated with resist to form a resist film thereon, followed by an electron is beam lithography thereof to form a resist pattern. The underlying tungsten film 25 is then selectively etched by using a dry-etching technique using the resist pattern, as shown in FIG. 3E. Thereafter, a mask pattern is formed on the bottom surface of the silicon wafer 21, followed by anisotropic back etching of the silicon wafer 21 by a wet etching technique using potassium hydroxide (KOH) as an etchant and the silicon nitride film 22 as an etch stopper Thus, the silicon nitride film 22 is formed as a membrane film having an implanted area 24, as shown in FIG. 3F. The wet etching step may be replaced by a dry etching step. Referring to FIGS. 4A to 4F, there is shown another fabrication process for fabricating the membrane mask of FIG. 2 according to another embodiment. The membrane mask is used for an electron beam lithography, for example. A silicon nitride film 32 is deposited to a thickness of 130 nm by using a LPCVD technique on the top surface of a silicon wafer 32 having a diameter of 200 mm. A mask having a specified opening is then formed on the bottom surface of the silicon wafer 31, followed by back etching of the silicon wafer 31 by a wet etching technique using KOH as an etchant, to thereby leave a film of the silicon wafer 31 having a thickness of 0.1 to 1 mm and underlying the silicon nitride film 32, as shown in FIG. 4A. The silicon nitride film 32 is then spin-coated with resist to form a resist film thereon, followed by patterning thereof to form a resist pattern 33, as shown in FIG. 4B. Subsequently, tungsten ions are selectively implanted into the silicon nitride film 32 by using the resist pattern 33 as a mask to form a heavy-metal-implanted area 34. The resist pattern 33 is then removed, as shown in FIG. 4C. The order of the steps may be reversed so that the back etching step of the silicon wafer 31 is conducted after the implanting of the tungsten ions. Thereafter, tungsten is sputtered onto the silicon nitride film 32 including the heavy-metal-implanted area 34, thereby forming a tungsten film 35 having a thickness of 15 nm, as shown in FIG. 4D. The tungsten film 35 is subjected to an electron beam lithographic patterning, whereby a portion of the tungsten film 35 is left on the heavy-metal-implanted area 34, as shown in FIG. 4E. Subsequently, the remaining film 31a of the silicon wafer 31 is removed by a back etching, whereby the silicon nitride film 32 is disposed as a membrane film, as shown in FIG. 4F. The final back etching step may be an isotropic etching step wherein an etching mask is not necessarily used. In the first fabrication process, there is a possibility that the silicon wafer may be subjected to a deformation due to a tensile stress applied from the membrane film after the back etching of the silicon wafer. On the other hand, in the second fabrication process, the tensile stress of the membrane film is removed to some extent before the film for the mask body is formed. In this process, the distortion of the silicon wafer after the back etching of the silicon wafer can be alleviated, whereby the membrane mask has a lower deformation. Since the above embodiments are described only for examples, the present invention is not limited to the above embodiments and various modifications or alterations can be easily made therefrom by those skilled in the art without departing from the scope of the present invention. For example, the back etching of the silicon wafer may be conducted before the deposition of the mask body film, such as before or after the implantation of the heavy metal ions. In addition, the membrane mask of the present invention can be applied to an X-ray lithography and an ion beam lithography as well as an electron beam lithography.
052290662	abstract	The present invention is a system which determines nuclear reactor control rod axial position using a deviation signature database generated from a current or reference signal pattern produced by one or more strings of axially dispersed fixed incore detector sections in the reactor core. The deviation signature database is produced by assuming deviant axial positions for the control rods in the core, calculating expected detector signals for the assumed positions and storing the deviation of expected signals from a calibration reference along with corresponding assumed rod positions. The signature database is periodically updated to take into account changed core conditions. When a change in detector responses is detected the system performs a signature analysis of the deviations in the signature database using the current deviation from the reference to search for the closest match. The change indicates not only the bank or individual rod that has moved but also the direction of movement allowing the search of the database to be circumscribed to the portion associated with the bank or individual rod and direction of movement. The closest match is used to incrementally search for the exact rod position by calculating expected response deviations for each assumed incremental move and comparing the expected response deviation to actual response deviations. If the system searches past the actual position, the last assumed position is output.
040574660	abstract	A method of conditioning the fuel of a nuclear reactor core to minimize failure of the fuel cladding comprising increasing the fuel rod power to a desired maximum power level at a rate below a critical rate which would cause cladding damage. Such conditioning allows subsequent freedom of power changes below and up to said maximum power level with minimized danger of cladding damage.
	summary
	summary
047568526	claims	1. A method of installing a vent in a nuclear waste storage container, which comprises the steps of: inserting a reversibly porous, air-diffusible, water-restrictive polymer plug, having an internal face, an external face, and a contact face connecting said internal face to said external face, a predetermined distance into a port formed in a wall of said container, said plug also provided with a means for securing said plug in said port, a means for sealing said contact face against a closed wall defined by said port in said wall of said container, and a means for receiving an insertion tool, located in an excess region of said plug adjacent said external face of said plug; and removing said excess portion of said plug protruding from said container wall after said step of inserting is completed, making it difficult to tamper with said vent when installed and providing a minimal area of exposure of said plug above said wall, protecting said plug from damage by external forces.
	description	The invention will be described with reference to an embodiment in which the apparatus for radiation analysis is formed by an X-ray analysis apparatus, more particularly, an X-ray diffraction apparatus. Therein, the analysing radiation has the form of X-ray radiation. However, there should be pointed out that the invention is applicable to all further apparatus for radiation analysis in which a collimator is used for the analysing radiation beam. FIG. 1 is a diagrammatic representation of a known X-ray analysis apparatus, in this case being an X-ray diffraction apparatus. In this apparatus a goniometer 4 is mounted on a frame 2. This goniometer 4 can be provided with an angular encoder for measuring the angular rotation of the X-ray source 7 which is mounted thereon and of the detector device 9 which is also mounted thereon. The goniometer is furthermore provided with a sample holder 8 on which a sample 10 is arranged. An angular encoder may be provided on the sample holder for the cases where measurement of the angular rotation of the sample is important. The X-ray source 7 includes a holder 12 for an X-ray tube (not shown in the Figure) which is secured in the holder by way of a fixing ring 20. This X-ray tube includes a high-voltage connector 15 for applying the high voltage and the filament current to the X-ray tube via high-voltage cable 18. On the same side of the X-ray tube, supply and discharge ducts 22 and 24 for the cooling water of the X-ray tube are provided. The tube holder 12 further includes an exit window for X-rays 44 and a unit 16 for parallelization of the X-ray beam (a Soller-slit collimator). The plates of the Soller-slit collimator 16 are parallel to the plane of drawing in such a way that the X-ray beam generated by the X-ray source 7 illuminates the sample 10 with a divergent beam. The detector device 9 comprises a holder 26 for a Soller-slit collimator, a holder 28 for a monochromator crystal, and a detector 30. The plates of the Soller-slit collimator in holder 26 are also parallel to the plane of drawing. If the X-ray source and the detector are both rotatable around the sample, it is not necessary for the sample to be mounted so as to be rotatable. However, it is alternatively possible to mount the X-ray source so as to be stationary as this may sometimes be necessary in the case of voluminous and heavy X-ray sources. In that case, the sample holder as well as the detector should be rotatable. The X-ray diffraction apparatus as shown in FIG. 1 also includes a processing device for processing the various measured data. This processing device comprises a central processing unit 32 with a memory unit 36 and a monitor 34 for the presentation of the various data and for the display of the measured and calculated result. The X-ray source 7, the detector device 9 and the sample holder 8, mounted on the goniometer 4, are all provided with a unit (not shown) for determining the angular position of the respective element relative to the scaled graduation of the goniometer. A signal representing this angular position is transferred to the central processing unit 32 via connection leads 38-1, 38-2 and 38-3. FIG. 1 shows a so-called Bragg-Brentano arrangement, which means that the X-rays emanating from a single point are again focused at one point after reflection by the sample 10, provided that the surface of the sample is tangent to a circle through the point of origin and the focal point. The sample 10 is irradiated by means of X-rays originating from the X-ray source 7. An anode 40, which forms part of the X-ray tube that is not further shown in this Figure, is diagrammatically represented in this X-ray source. In anode 40 the X-rays are generated in a customary manner by exposing this anode to high-energetic electrons. As a result, X-rays 42 emanating from X-ray window 44 are generated in the anode. The said point of origin in the arrangement shown in FIG. 1 is not formed by a single point, but by a line focus 41 on the anode which line focus is perpendicular to the plane of drawing. Said focal point is formed by the point of union 43 of the beam 45 leaving the sample at the area of the entrance of the detector 30. Consequently, this arrangement has a focusing effect only in the plane of drawing. FIG. 2 shows a respective view of an embodiment of a variable Soller-slit collimator in which the plates of the collimator have a rectangular shape. The collimator shown comprises a stack of collimator plates 46 with spacings 48. All the plates in this collimator have the same dimensions. A radiation beam 45 whose aperture angle is bounded by the collimator is incident in parallel with the plane of the collimator plates 46. The angle of aperture xcex1 of the radiation beam is given by twice the ratio of spacing d between the plates 46 to the collimating element length L exposed to the radiation beam (see also FIG. 2b), so that the following holds xcex1=2d/L. The value of the magnitude L may be varied by rotating the collimator plates around a shaft 50 that is perpendicular to the plane of the plates 46. For this purpose, a movement mechanism is provided, in this embodiment formed by a shaft 50 and a drive unit 52 in which the shaft 50 is carried in bearings and which is fixedly connected to the analysis apparatus the collimator forms part of. The drive unit comprises, for example, a motor for rotating the shaft, which motor is controlled by a control unit 54 which may form part of a computer belonging to the analysis apparatus. When the measurements to be carried out by the analysis apparatus so require, the collimator plates 46 are rotated around the shaft 50 until the correct aperture angle is reached, that is, until the relationship xcex1=2d/L, where xcex1 is a prescribed value, has been satisfied. FIG. 3 shows a perspective view of a second embodiment of a variable Soller-slit collimator according to the invention. This embodiment is pre-eminently suitable for the devices in which the radiation beam is strongly diverging or converging in a plane parallel to the collimator plates. This situation may occur, for example, in a spectrometer of the Bragg-Brentano type. With a beam so divergent, the value of L (i.e. the collimator plate length L exposed to the radiation beam 45) is not the same for all the rays in the radiation beam. This may be a disadvantage for measurements that require a high degree of accuracy. It can be demonstrated that for such measurements a Soller-slit collimator having elliptically shaped plates eliminates this disadvantage entirely or to a large extent. Just like in the collimator as shown in FIG. 2, the collimator in FIG. 3 is driven via shaft 50 in the same way as has already been described with reference to FIG. 2. FIG. 4 shows a perspective view of an embodiment of a variable Soller-slit collimator with X-ray optical fibres according to the invention. Such fibres are known per se for influencing radiation beams of X-rays. With such fibres, a high degree of collimation, i.e. a very small aperture angle of the radiation beam, may be obtained. The collimator shown in this Figure comprises a two-dimensional stack of X-ray fibres 60. The X-ray fibres 60 have the same cross-section, but a length that depends on their height in the stack. Parallel with the axial direction of the X-ray fibres 60, a radiation beam 45 is incident whose aperture angle is bounded by the stack of X-ray fibres. The aperture angle of the radiation beam is determined by the ratio of the internal cross section and the length of the hollow fibre. The aperture angle may thus be varied by reciprocating the collimator. For this purpose, a movement mechanism is provided in this embodiment, which is formed by a holder for the stacking of X-ray fibres, which holder comprises two guides 62 which may be reciprocated by a driving rod 64, the guides 62 being led along parts 56 of the arrangement of the analysis apparatus. The driving of said movement is performed by a drive unit 52 in which the driving rod 64 is carried in bearings and which is also fixedly connected to the analysis apparatus. The drive unit comprises, for example, a motor for reciprocating the driving rod, which motor is controlled by a control unit 54 which may form part of a computer belonging to the analysis apparatus. When the measurements to be performed by the analysis apparatus so require, the collimator is reciprocated until the correct aperture angle is reached.
056299648	summary	A neutron absorbing apparatus which includes two adjacent neutron absorbing plates and a mounting assembly with latching means configured to be easily secured to fuel assemblies while the fuel assemblies remain under water in a fuel storage rack, thereby eliminating the need to remove the fuel assemblies or the fuel storage rack for installation. The two neutron absorbing plates are positioned orthogonally to form a chevron cross section which can be placed about the fuel assemblies by insertion in the existing space between the fuel assemblies and the cell walls of a fuel storage rack. A prescribed orientation of the chevron configured neutron absorbing plate in the cells of the fuel storage rack together with the selected use of a single neutron absorbing plate economically provides sufficient neutron absorption in all radial directions about the fuel assemblies to maintain safe storage conditions in closely packed fuel storage racks. FIELD OF THE INVENTION The present invention generally relates to the apparatus and method used for the close packing of nuclear fuel assemblies and more specifically to a neutron absorber which is attached directly to and partially surrounds a fuel assembly. The means for attachment to the fuel assembly facilitates the installation of the present invention on the fuel assembly while it is stored in an underwater fuel storage rack without the need to remove the fuel assembly or the fuel storage rack. BACKGROUND Nuclear power plants are currently required to store their spent fuel assemblies on site. Storage is accomplished by placing the spent fuel assemblies in closely packed fuel storage racks located at the bottom of on site storage pools. To provide maximum storage space, the storage racks contain a large number of adjacent storage cells, each cell being capable of accepting a spent fuel assembly. The walls of the cells include a neutron absorber to avoid criticality and to permit the close packing of the nuclear fuel assemblies. This type of storage has been in use for over 15 years and in many sites the neutron absorber in the cell walls has begun to deteriorate. In order to extend the period over which the fuel assemblies may be stored in this manner, it is necessary to either replace the neutron absorber in the cell walls or to add an additional neutron absorber to the cell or the fuel assembly. Although there are a wide variety of neutron absorbers, as well as methods for their fabrication and installation which theoretically could be applied in this application, there are generally no prior art neutron absorbers or methods capable of permitting on site installation in an economically feasible manner. The economic aspect of the installation of a neutron absorber is one of the most important because the retrofitting of the nuclear fuel storage racks at one site alone can cost tens of millions of dollars. The high cost is due in large measure to the great expense for new storage rack design, fabrication, licensing, and installation, as well as the expense for old rack removal and radioactive waste disposal incurred during this removal. An example of an economically unsuitable prior art approach which could technically be applied to address the retrofitting process described above is contained in U.S. Pat. No. 4,787,029. In this patent, a fuel rack is described that is designed to store closely packed fuel assemblies. Within this fuel rack, a neutron absorber is encased in the cell walls that surround each spent fuel assembly. To apply this fuel rack to a retrofitting application, all the spent fuel assemblies in an old installed rack would first have to be removed and placed in temporary storage. Following this, the old rack would have to be removed and disposed of as radioactive waste. Finally, the new rack would have to be installed and the spent fuel assemblies would then have to be placed in the new storage rack, all at great expense. A second example of an unsuitable prior art approach for this retrofitting application is provided by U.S. Pat. No. 5,198,183. This patent illustrates a neutron absorber that may be inserted within the fuel assembly itself. The application of the neutron absorber described in this patent is also not economically feasible for retrofitting applications because it would require the steps of retrieval of the spent fuel assemblies from the underwater storage rack, the modification of the fuel assemblies by the installation and locking in place of the neutron absorber within the fuel assembly, and finally the return of the modified fuel assemblies to their cells in the underwater fuel rack, all of which would have to be carried out on site by skilled operators using specialized remotely operated equipment. A third example of an unsuitable prior art approach for this retrofitting application is provided by a commercially available thick neutron absorber formed of boron carbide in an aluminum matrix. This neutron absorber is typically 0.1 to 0.2 inch thick and is recommended for installation about all four sides of a fuel assembly. This recommendation may be prompted by the relatively poor absorption properties of boron. By specifying the placement of the thick neutron absorber about all four sides of an unmodified fuel assembly, it becomes difficult, if not impossible, to install this absorber while the fuel assembly remains in a storage rack because there is usually insufficient clearance between the fuel assembly and the wall of the storage rack cell to accept such a thick walled neutron absorber. In an attempt to compensate for this problem, it is recommended that the fuel assembly be modified by retrieving it from the storage rack and removing the flow channel to make room for the thick walled absorber. If such a procedure is followed, the user must incur the cost of retrieval of each spent fuel assembly, disposal of the radioactive flow channel, installation of the new neutron absorber and return of the fuel assembly to the fuel rack. In attempting to solve the fuel assembly storage problem, this approach has created another nuclear waste storage and disposal problem which generally cannot be carried out on site. In addition, the thick walled neutron absorber presents a potential failure mode over its lifetime. This absorber is first fabricated as a single plate which is then folded to have a rectangular cross section. The area in which the fold takes place contains the neutron absorbing material. Microscopic cracks occurring along the line of the fold could later develop into leaks which could reduce the effectiveness of this type of neutron absorber. Unfortunately, this is the exact problem that this absorber was designed to correct. These and other limitations of the prior art are overcome by the present invention which is described in the following detailed specifications. SUMMARY OF THE INVENTION In a preferred embodiment of the present invention, a neutron absorber plate is folded into a chevron cross sectional pattern, enabling the neutron absorber to cover two surfaces of a fuel assembly. Attached to the the top end of the chevron configured neutron absorber plate is a mounting plate adapted to fit over the top of a BWR fuel assembly and be secured to the assembly by means of a latch mounted on the mounting plate. This apparatus containing the neutron absorber plate is lowered into a storage pool where it is guided into position over a cell of the fuel storage rack containing a fuel assembly. The apparatus is then lowered further to insert the chevron configured plate between the cell walls and the fuel assembly. Clips on the lower end of the neutron absorber plate grip the lower end of the fuel assembly while the latching means on the mounting plate is used to secure the mounting plate to the top of the fuel assembly. The latching means is easily secured to the fuel assembly by tightening a captured screw contained within the latching means. The captured screw is tightened by means of a socket wrench affixed to the end of an extended shaft. The mechanism for lowering the absorber plates is similar to that which is used to place the fuel assemblies in storage. No specially trained personnel with metal working skills or costly equipment is required, nor is there any requirement for the removal or rework of any equipment, such as fuel racks or assemblies. Multiple absorber plates having the chevron configuration of the present invention are each positioned in their respective cells in the same quadrant in which the first installed absorber plate is placed to provide absorber coverage in all radial directions about the fuel assemblies. The only areas not covered by this orientation of the absorber plates are two outside surfaces of the fuel rack which generally do not require coverage because they face an open water area. The open water serves as the neutron absorber in such cases. However, additional absorber coverage may be provided on these surfaces, if desired, by applying to the outside of the fuel rack a flat plate form of the invention which has been designed for this purpose.
054208998	summary	TECHNICAL FIELD This invention relates to the field of nuclear reactors in general and to a tool used to lift a nuclear reactor fuel bundle channel from a fuel bundle assembly in particular. BACKGROUND Typically, BWR nuclear fuel bundles and channels are delivered to reactor sites in separate shipping containers. At the sites, the fuel bundles are removed from their shipping containers, inspected, and stored hanging on racks in a fuel preparation room. Before moving the fuel bundle to the reactor, the channel is installed over the bundle. There are occasions, however, when the channel must be removed from its associated fuel bundle. Once the channel has been installed on the fuel bundle, however, with the lower end of the channel fitted over the finger springs in the lower tie plate assembly, and with the top of the channel in place, snug against the upper tie plate, removal of the channel can be problematic. The channel is initially moved upwardly off the fuel bundle (about ten inches) so that a crane lift device can be attached to the channel. After the crane lift device has been attached, the crane hook is coupled to the lift device and the crane is then used to remove the channel from the fuel bundle. The initial upward movement of the channel currently is done manually to gain the approximate ten inches of elevation required to clear the upper tie plate. Typically, one or two people lift the channel and a third person then connects the crane lift device. If the channel is dropped during this procedure, however, the channel as well as the fuel bundle can be damaged. There is thus a need for a device which will permit a fuel bundle channel to be removed from a fuel bundle in a simpler, more reliable and less labor intensive manner. SUMMARY OF THE INVENTION This invention provides a locking channel grapple which permits channel removal from a fuel bundle to be accomplished reliably and safely by one person. The grapple device in accordance with this invention is adapted to attach to a crane lifting hook and then lowered over a fuel bundle. The grapple is designed to provide clearance so it can move down without interference over the upper tie plate bail and into position over the channel. The grapple includes screw actuated lifting feet fixed to a respective pair of lever arms. The lifting feet are positionable under the channel gussets at opposite corners of the channel. The grapple device has a central shaft to which the lever arms are pivotally mounted. The shaft is formed with screw threads at a lower end thereof, threadably receiving a cross piece pinned to the lever arms at locations between the ends of the latter. The pins are slideable within slots formed in the respective lever arms so that, when the shaft is turned by a serrated knob or handle, the lever arms are caused to swing outwardly moving the lifting feet under the channel gussets. The lifting feet on each lever arm are forked so that spaced lifting elements will fit around the upper tie plate boss or bosses on which the channel gussets rest, and which is formed with a threaded hole for receiving a bolt passing through the channel gusset. The screw action of the lever arms effectively holds the lifting feet under the channel gussets, preventing from slipping from under the channel gusset(s) during lifting. The lifting feet on each lever arm also have a secondary foot or slider which is captured in a slot between the spaced lifting elements, permitting the movable secondary foot to be located centrally under a respective channel gusset as described below. The secondary foot, unlike the forked lifting feet, has a hole in its end which, after the channel is lifted away from the tie plate boss, can be aligned with the bolt hole in the channel gusset by sliding the secondary foot to its extreme outside position. A pair of conventional ball lock pins are attached to the grapple device by chains or cables so they will be readily available for use with the sliders described above. Specifically, after the hole in the secondary foot of each pair of lifting feet is aligned under a respective channel gusset hole, the ball lock pin is inserted through the channel gusset hole and through the hole in the secondary foot, further insuring against relative lateral movement between the channel and the grapple. The ball lock pin will safely secure the channel to the grapple until the channel is securely back in its storage place, or until it is re-mounted on the fuel bundle. In its broader aspects, therefore, the present invention relates to a grapple for use with a fuel bundle channel of a nuclear reactor wherein the channel is provided with a pair of gussets in opposite diagonal comers of an upper end of the channel, each gusset having a hole therein, the grapple comprising a pair of lever arms, each provided with a channel lifting foot at a lower end of the respective lever arm, the lever arms movable to a channel lifting position wherein the channel lifting foot of each lever arm is located under a respective one of the pair of channel gussets, and wherein each lifting foot includes a pair of laterally spaced lifting elements such that the lifting foot may engage the underside of the gusset on either side of the gusset hole.
	abstract	The invention provides a method for isolating scandium, the method having the steps of dissolving titanium nuclear targets to create a solution; contacting the solution with a resin so as to retain scandium on the resin and generate an eluent containing titanium; contacting the scandium-containing resin with acid of a first concentration to remove impurities from the resin; and contacting the scandium-containing resin with an acid of a second concentration to remove scandium from the resin.
	description	This application is a continuation of PCT/DE 03/02890, Sep. 1, 2003. 1. Field of the Invention The present invention concerns a method for operating a computed tomography apparatus with an x-ray radiator rotatable around a system axis, with an x-ray detector and with a radiator-side gating device that has two opposite absorber elements that can be adjusted in a straight line, in particular that can be adjusted with regard to their separation from one another, for variable delimitation of the ray beam. An examination subject is scanned during rotation of the x-ray radiator and relative translational movement between the x-ray radiator and the examination subject in the direction of the system axis. 2. Description of the Prior Art In an examination of an examination subject or a patient in an x-ray diagnostic apparatus, the examination subject is moved into an x-ray beam emitted by an x-ray source, and the radiation actuated by the subject is detected by an x-ray detector. The examination subject is thus located in the beam path between the x-ray source and the x-ray detector. The typical x-ray tubes used as x-ray radiators emit x-ray radiation in a significantly larger solid angle than is necessary for examination at the patient. In order to prevent unnecessary radiation exposure at the patient, unnecessary x-rays are gated (blanked out). For this, in conventional x-ray apparatuses it is known to dispose a radiator-side gating device immediately after the x-ray radiator in the beam path. Such gating device is also designated as a primary beam diaphragm. For example, such a primary beam diaphragm, with diaphragm plates that can be moved opposite to one another as absorber elements, is known from European Application 0 187 245. In computed tomography apparatuses with multi-row x-ray detectors, a detector-side beam diaphragm (or a beam diaphragm near to the detector) that is mounted in the beam path between the patient and the x-ray detector is also frequently used in addition to a radiator-side gating device that is arranged in the beam path between the x-ray radiator and the patient. It is thereby possible to shadow one or more detector rows of the multiple detector rows and to use the remaining detector rows as active detector rows. Such a collimator is known from U.S. Pat. No. 6,396,902 the entire bearing body composed of x-ray-absorbing material must be moved. This occurs by rotation of the bearing body, which is why the bearing body is also curved around a second axis. In order to also be able to bring another diaphragm slit into the matching position, the rotation axis would have to be located at the height of the focus of the x-ray radiator. This is at best possible with very large mechanical effort. Alternatively, the rotated bearing body would have to be readjusted into the correct position via a shifting movement, which is likewise very elaborate. Moreover, the production of a bearing body curved around two axes is expensive, because this must also be produced from x-ray-absorbing material, meaning from a material with a high atomic number. A further disadvantage of the x-ray collimator known from U.S. Pat. No. 6,396,902 is that only a finite number of slits of discrete width can be applied or, respectively, introduced on or in the bearing body. An object of the present invention is to provide a method for operating a computed tomography apparatus having a beam-gating diaphragm disposed near and preceding the radiation detector, wherein over-radiation of the patient at the beginning and at the end of a scan are avoided. The above object is achieved in accordance with the present invention in a method for operating a computed tomography apparatus wherein the movable elements of a beam-gating diaphragm disposed preceding the radiation detector are adjusted in an asymmetrical manner. According to the invention, this object is achieved by a method for operation of a computed tomography apparatus with a radiator-side gating device having absorber elements exhibiting a curved shape. The gating device has an adjustment device that acts on the absorber elements such that the absorber elements can be moved perpendicularly to their longitudinal direction, so they can be adjusted (displaced) relative to one another. The elements can be moved in a direction parallel to the system axis. The absorber elements exhibit the curved shape at their outer contour that delimits the x-ray beam, i.e. for example at an edge forming a diaphragm slit. To prevent unnecessary radiation exposure for the examination subject, the gating device is operated in accordance with the inventive method with absorber elements opened to different widths with regard to a center beam of the active, (i.e. radiation detecting) surface of the x-ray detector. This prevents over-radiation of the patient at the beginning and at the end of a scan movement of a scan (in particular a spiral scan), by allowing the gating device to be adjusted quasi-asymmetrically. For example, before the beginning and/or after the end of the scan movement, in particular the relative movement, one of the absorber elements is positioned in a closed position and the other absorber element is positioned in an open position. After the beginning of the scan movement, in particular the relative movement, the absorber element located in the closed position is preferably opened in synch with the scan movement, in particular with the relative movement. It is likewise possible that, before the end of the scan movement (in particular the relative movement), one of the absorber elements located in the open position is closed in synchronization with the scan movement, in particular with the relative movement. A dynamic variation of the collimation width is thus effected with the gating device. In an advantageous manner, the slit width is continuously or freely selectable between the curved absorber elements or diaphragm jaws, and thus the slice thickness that is adjustable at the computed tomography apparatus can assume non-discrete values. Wide detector rows can be only partially irradiated, and thus slices that are thinner than the width of the detector elements are also possible in a simple manner. Moreover, the gating device requires absorber elements that are necessarily curved only in one direction or in one plane and thus exhibit, for example, a shape as is created given bending of a plate around a straight edge (for example “banana shape”). The gating device can thus also be produced simply. The variation that is continuous to the greatest possible extent, of the slit width or the collimation width possible in the computed tomography apparatus allows—as already mentioned—a free selection of the slice thickness and a flexible selection of the active rows of detector elements. However, a readjustment of the diaphragm setting given a change of the focus size in the x-ray receiver occurring during the operation is still possible. Since the absorber elements can be moved independently of one another, it is possible to move the absorber elements not only opposite one another, but also concurrently in the same direction. For example, a diaphragm readjustment is possible given a variation of the focus position in the diaphragm rays that occurs during the operation (focal spot tracking). This means that the entire slice can also be shifted in the z-direction with a constant slice width. Moreover, a dynamic variation of the collimation width is possible, whereby (for example) an unwanted over-radiation at the beginning and at the end of a spiral scan can be reduced, by one of the absorber elements remaining closed at the beginning of the scan and only being opened at the beginning of the scan with the beginning of the translational patient bed movement in the direction of the system axis. The same is true in reverse for the end of the scan. The adjustment device for each of the absorber elements indicates a separate adjustment unit, whereby the adjustment units are preferably fashioned for linear movement of the appertaining absorber element. With such a linear movement, it is ensured in an advantageous manner that sections of the curved absorber element matching one another still lie opposite one another after a relative movement in the direction of the system axis. Each adjustment unit has a (preferably mutual) linear guide as well as a drive acting on the absorber elements. As an alternative, each adjustment unit can have a linear motor, for example with a corresponding guide. The curvature of the absorber elements proceeds in a plane perpendicular to the system axis. The curvature in particular exhibits the shape of a circular arc whose center point lies in the focus of the x-ray radiator. Identical distances between the focus and all ray-delimiting edge regions of the absorber elements are thereby achieved in a simple manner. According to another embodiment, the curvature radii of the absorber elements differ from one another by a value of 0.5% to 10% from the interval. The advantage that results from this is to enable a hundred-percent closure of the diaphragm, because due to finishing tolerances it is normally not sufficient for the absorber elements to cease movement upon coming into contact with stop. Rather, they must at least slightly overlap, viewed in the direction of the x-ray beam. Such an overlapping is possible in an advantageous manner without scraping as a result different curvature radii. A CT apparatus of the third generation is shown in FIG. 1 in section. Its data acquisition arrangement includes an x-ray radiator 2 with a gating device 3 positioned in front of it, near the source, and an x-ray detector 5, fashioned as a laminar array of a number of rows and columns of detector elements (one of these is designated 4 in FIG. 1), with an optional beam diaphragm (not shown) positioned in front of the x-ray detector 5, close to the detector 5. For clarity, in FIG. 1 only four rows of detector elements 4 are shown; however, the x-ray detector 5 can have further rows of detector elements 4, optionally also with different widths b. The x-ray radiator 2 with the gating device 3 on one side and the x-ray detector 5 with its beam diaphragm on the other side are mounted opposite one another on a rotary frame (gantry) (not shown), such that a pyramidal x-ray beam emitted by the x-ray radiator 2 in the operation of the CT apparatus 1 and gated by the adjustable gating device 3 (the ray beams of which x-ray beam are designated with 8) strikes the x-ray detector 5. By means of the gating device 3 and, if applicable, by means of the detector-proximate beam diaphragm, a cross-section of the x-ray beam is adjusted such that only that region of the x-ray detector 5 is uncovered (exposed) that can be directly struck by the x-ray beam. In the operating mode illustrated in FIG. 1, there are four rows of detector elements that are designated as active rows. If applicable, further existing rows are covered by the detector-proximate beam diaphragm and are therefore not active. The gating device 3 primarily serves to prevent an unnecessary radiation exposure of the examination subject, in particular a patient, by keeping rays that otherwise do not arrive at the active rows away from the examination subject or patient. The rotary frame can be rotated around a system axis Z by means of a drive unit. The system axis Z is parallel to the z-axis of a spatial rectangular coordinate system shown in FIG. 1. The columns of the x-ray detector 5 likewise proceed in the direction of the z-axis, while the rows (whose width b is measured in the direction of the z-axis and is, for example, 1 mm) proceed to the system axis Z and the z-axis. In order to be able to bring the examination subject, for example the patient, into the beam path of the x-ray beam, a support device 9 is provided that can be shifted parallel to the system axis Z, thus in the direction of the z-axis, such that a synchronization exists between the rotational movement of the rotary frame and the translational movement of the support device 9 with the ratio of translation speed to rotation speed constant. This ratio is adjustable by setting a desired value selected for the infeed h of the support device 9 per rotation of the rotary frame. A volume of an examination subject located on the support device 9 can thus be examined in the course of a volume scanning. The volume scanning is effected in the form of a spiral scan in the sense that, during rotation of the rotary frame and simultaneous translation of the support device 9 per rotation of the rotary frame, a number of projections are acquired from various projection directions. During the spiral scan, the focus F of the x-ray radiator 2 moves on a spiral track S relative to the support device 9. A sequence scan is also possible as an alternative to this spiral scan. The measurement data, read out in parallel during the spiral scan from the detector elements 4 of each active row of the detector system 5 and corresponding to the individual projections, are subjected to a digital-analog conversion in a data processing unit 10, and are serialized and transferred to an image computer 11 which shows the result of an image reconstruction on a display unit 16, for example a video monitor. The x-ray radiator 2, for example an x-ray tube, is supplied with the necessary voltages and currents by a generator unit 17 (optionally likewise mutually rotating). In order to be able to adjust this to the respectively necessary values, a control unit 18 with keyboard 19 that allows the necessary adjustments is associated with the generator unit 17. All operation and control of the CT apparatus 1 ensues by means of the control unit 18 and the keyboard 19, with the control unit 18 is connected with the image computer 11. Among other things, the number of the active rows of detector elements 4 (and therewith the position the gating device 3 and of the optional detector-proximate beam diaphragm) can be adjusted, for which purpose the control unit 18 is connected with adjustment units 20 and 21 associated with the gating device 3 and the optional detector-proximate beam diaphragm. Furthermore the rotation time that the rotary frame requires for a complete rotation can be adjusted by means of the drive unit 22 associated with the rotary frame being connected with the control unit 18. FIG. 2 shows the gating that results with a known gating device 3A with two separate absorber elements 30A, 31A. Shown is an x-ray beam with edge rays 8A that emanates from a focus F of an x-ray radiator 2A. Both edge rays 8A emanating from the focus F and passing the (in FIG. 2) rear absorber element 30A respectively cover a distance d2 from the absorber element 30A. In contrast to this, the comparable distance d1 in the indicated central ray 36 is less than in the edge rays 8A. This is also true for the edge rays on the opposite side of the slit 32A. The result is that an x-ray beam whose outer contour 34A is not rectangular is gated on the x-ray detector 5A with its individual detector elements 4A shown in cross-section. In order to fully irradiate all detector elements 4A of the detector row (with width b, the outer contour 34A must be set such that its width B2 at the edge approximately corresponds to the width b of the detector row. As a result of the different distances d1≠d2, a larger width B1 of the outer contour 34A of the x-ray beam then results in the middle of the detector row. The portion of the x-ray beam occurring in this barrel-shaped region (here shown exaggerated, but nevertheless disturbing with regard to the radiation dose) is ultimately not used. The gating device 3 of the CT apparatus 1 according to the invention according to FIG. 1 is illustrated in FIG. 3 in a schematic representation and perspective view. The gating device 3 has two curved absorber elements 30, 31, between which a slit 32 is formed that can pass the x-rays emanating from the focus F of the x-ray radiator 2. The absorber elements 30, 31 (produced from heavy metal, for example tungsten and/or tantalum) are curved in a circular arc, with the middle point of the circular arc lying in the focus F of the x-ray radiator 2. It is thereby ensured that the respective spacings of the edge rays 8 and of a central ray 36 respectively measured from the focus F to the absorber elements 30 (or 31), exhibit the same value d. In an advantageous manner, this causes the x-ray beam gated by the x-ray detector 5 to exhibit in cross-section a rectangular outer contour 34 whose constant width B can be precisely adapted to the width b of one or more detector rows. Both absorber elements 30, 31 can be moved or driven independently of one another, in parallel or opposite, which is indicated by corresponding double arrows 40, 41 in FIG. 3. FIG. 4 shows how the gating device 3 (shown schematically) can be accommodated in a common housing 50, together with a filter device 45 with one or more (copper) spectral filters 46 (with drive element 47 belonging to the filter changer) and with a wedge filter 48 serving for variable attenuation of the x-ray beam. The housing 50 has an entrance opening 51 on the side of the focus F and an exit opening 52 on the opposite side. Moreover, FIG. 4 shows a separate adjustment unit 60 and 61 for each of the absorber elements 30, 31, with which the absorber elements 30, 31 can be moved linearly, independently of one another. In the exemplary embodiment of FIG. 4, the first adjustment unit 60 for one of the absorber elements 30 includes a first drive 62 fashioned as a step motor, which acts on one of the absorber elements 30 via a first transmission 63 and via a first toothed belt 64. For the other absorber element 31 (not visible in FIG. 4), a second drive 67 (likewise fashioned as a step motor) and a second transmission 68 are correspondingly present in the second adjustment unit 61. Both drive units 62, 67 act (for example via different spindle guides) on the two absorber elements 30, 31 moving linearly in the z-direction on the same linear guide 65. The gating device 3 according to FIG. 3 is shown in FIG. 5 in a perspective representation according to a second exemplary embodiment. The special banana-like shape of the diaphragm backs 30, 31 is better visible in FIG. 5. Moreover, it can be seen in FIG. 5 that the common linear guide 65 can have a left-side first track 65A as well as a right-side second track 65B. The gating device 3 of FIG. 5 is explained again in FIG. 6 in a cross-section representation in the z-direction. In FIG. 6 it can be seen that the absorber elements 30, 31 are slightly displaced relative to one another in the height direction y, essentially corresponding to the direction of the radiated x-ray beam, in order to prevent passage of x-ray radiation (dependent on finishing tolerances) given a complete closing of the gating device 3. In order to be able to execute the overlap of the absorber elements 30, 31 without friction, it is advantageous that the curvature radii of the absorber elements are slightly different. For example, these are 197 mm and 200 mm, respectively. A third exemplary embodiment of the gating device according to FIG. 3 is shown in detail in FIG. 7. This exemplary embodiment is essentially identical to the exemplary embodiment according to FIG. 5, but differs by the respective adjustment units 60, 61 for the absorber elements 30 and 31 a first linear motor 71 with a guide and a second linear motor 72, likewise with corresponding guide. Instead of a linear guide, other linear adjustment possibilities can be used. With the gating device 3, in connection with a focus-phi-z regulated control, it is possible to make appropriate adjustments to account for variation of the focus position or focus size in the x-ray radiator 2 in the diaphragm adjustment. Although modifications and changes may be suggested by those skilled in the art, it is the invention of the inventors to embody within the patent warranted heron all changes and modifications as reasonably and properly come within the scope of their contribution to the art.
	summary
	description	The present invention relates to an apparatus for shielding X-rays. The invention further relates to an X-ray device such as an X-ray spectrometer or an X-ray diffractometer comprising an X-ray shielding apparatus. The advent of so-called X-ray lenses (also called “Kurnakhov lenses”) over two decades ago has prepared the ground for lightweight, portable X-ray devices with a broad spectrum of applications in areas as different as metallurgy, geology, chemistry, forensic laboratories and customs inspection. In a similar way as conventional optical lenses redirect visible or near-visible photons, X-ray lenses redirect electromagnetic radiation in the X-ray radiation band and may thus be used to collimate or focus a beam of X-rays. An X-ray lens is conventionally formed from a plurality of capillaries. Each capillary guides the X-rays captured at a front end thereof to the opposite end by way of total external reflection. This rule applies so long as the angle of incidence at the front end does not exceed a critical angle. If the critical angle is exceeded, X-rays can no longer be captured within the capillary. In such a case, the capillary becomes transparent to the X-rays. Originally, an X-ray lens was a bulky device with dimensions in the region of up to several meters. These large dimensions were mainly the result of separate support structures that were required to keep the individual capillaries in place. Commercial use of X-ray lenses became feasible when it was recognized that the support structures can be omitted if the X-ray lens is produced out of one or more glass capillary bundles using glass drawing techniques. By fusing the capillary mantles together, separate support structures became obsolete. Today, the commercial application of X-ray lenses includes portable X-ray spectrometers, lightweight X-ray diffractometers and many other small-sized devices. Such devices typically comprise an X-ray source (such as an X-ray tube), an X-ray lens and a detector. X-rays emitted from the X-ray source are focused by the X-ray lens onto a tiny spot on a sample. The detector detects the X-rays emitted back from the sample and generates an output signal that can for example be spectrally analysed to determine the chemical elements included in the sample. As is well known, the exposition to X-rays is hazardous to human beings such as operators of X-ray spectrometers X-ray diffractometers and other X-ray devices. Accordingly, the construction of such devices necessitates X-ray safety considerations. There are various approaches to cope with the hazards resulting from X-ray radiation in X-ray devices. One approach is the incorporation of shielding materials. If the X-ray devices include only stationary components, shielding can quite easily be effected by means of stationary shielding walls. In devices with movable components such as a positioning mechanism for an X-ray lens, however, it is often necessary to provide a more sophisticated shielding mechanism that includes an adjustable X-ray passage. Accordingly, there is a need for an X-ray shielding apparatus having an adjustable X-ray passage. Also, there is a need for an X-ray device including an X-ray shielding apparatus with an adjustable X-ray passage. According to a first aspect of the invention, an X-ray shielding apparatus having an adjustable X-ray passage is provided. The X-ray shielding apparatus comprises a stationary member having an aperture and one or more shielding members that are movable in relation to the stationary member and made from an X-ray shielding material. The one or more shielding members define an X-ray passage within the aperture that is smaller than the aperture, and the movement of the one or more shielding members is restricted such that the one or more shielding members in each position relative to the stationary member cover the aperture at least in an area outside the X-ray passage. The X-ray passage may for example be defined by an opening of a single shielding member or by the intersection of openings of several shielding members. In one variation, the one or more shielding members completely cover the aperture in an area outside the X-ray passage. Depending on the shielding requirements, it may in another variation be sufficient to cover the aperture not completely, but at least in a portion surrounding the X-ray passage. A guiding mechanism for guiding the movement of the at least one shielding member in relation to the stationary member may be provided. The guiding mechanism may include a guided element coupled to one of the stationary member and the least one shielding member. The guided element may be constituted by a protrusion coupled to the at least one shielding member. Additionally, the guiding mechanism may include a guiding structure coupled to the other one of the stationary member and the at least one shielding member and defining a stop for the guided element. The guiding structure is for example constituted by a rim of the stationary member or of the at least one shielding member. In one embodiment, the guiding structure is constituted by a rim of the aperture of the stationary member. The one or more shielding members may have various shapes. Preferably, the shielding members have a substantially planar shape (such as a disc or washer). In one example, the at least one shielding member is constituted by an annular ring plate. As mentioned above, the X-ray shielding apparatus may either comprise a single shielding member or a plurality of individual shielding members. If two or more shielding members are provided, the individual shielding members may be arranged one behind the other and may collectively cover the aperture except for the area of the X-ray passage. In one implementation, the X-ray shielding apparatus comprises a first shielding member with a first opening and a second shielding member with a second opening. The second opening may have a smaller size than the first opening and may thus substantially define the X-ray passage. Moreover, the first shielding member may have a first outer diameter and the second shielding member may have a second outer diameter substantially smaller than the first outer diameter. The X-ray shielding apparatus may include a tube member extending through the first and the second (and any further) shielding members. In one embodiment, the tube member has a diameter that essentially corresponds to the diameter of the smallest one of the first and the second (and any further) openings. Preferably, the tube member is constituted by an X-ray lens or is configured to receive an X-ray lens. The axial position of the tube member relative to one or both of the first and second shielding members may be adjustable (e.g. for positioning an inlet focus or an outlet focus of the X-ray lens). According to a further aspect of the invention, an X-ray device is provided. The X-ray device comprises an X-ray source, an X-ray lens for redirecting X-rays emitted from the X-ray source, and an X-ray shielding component for selectively transmitting X-rays towards or through the X-ray lens. The X-ray shielding component includes a stationary member having an aperture and one or more shielding members movable in relation to the stationary member and made from an X-ray shielding material, wherein the one or more shielding members define an X-ray passage within the aperture that is smaller than the aperture and wherein the movement of the one or more shielding members is restricted such that the one or more shielding members in each position relative to the stationary member cover the aperture at least in an area outside the X-ray passage. The X-ray lens may comprise one or more bundles of capillaries. Furthermore, the X-ray device may comprise a positioning component for the X-ray lens that is disposed downstream of the shielding component and that is made from a material (such as a aluminium) essentially transparent to X-rays. In the following, the invention will exemplarily be described with reference to a preferred embodiment in the form of an X-ray spectrometer comprising an X-ray shielding apparatus with one stationary member and two movable shielding members. It should be noted that the invention can also be practised in other X-ray devices such as diffractometers and in shielding apparatuses having a different structure (e.g. including more than one stationary member and/or including one, three or more shielding members). Also, while the invention is hereinafter described with reference to shielding members having central circular openings, the X-passage may alternatively be defined by shielding members having eccentric openings or having any other kind of means for defining the X-ray passage. FIG. 1 shows a cross sectional view of an X-ray spectrometer 10 according to an embodiment of the present invention. The spectrometer 10 includes an X-ray source 12 constituted by an X-ray tube. The spectrometer 10 further comprises a shutter 14, a positioning/shielding module 16, a sample housing 18 with a sample 20 arranged on a sample positioning platform 22, and a detector 24. An X-ray beam generated within the X-ray source 12 and indicated by reference numeral 26 passes along an optical axis 30 through the shutter 14. An X-ray (or Kumakhov) lens 28 focuses the X-ray beam onto a tiny spot on the sample 20 (note that the size of the sample 20 is exaggerated in the schematic drawing of FIG. 1). The detector 24 collects the X-rays emitted back from the sample 20 and outputs a spectrum signal indicative of the chemical elements included in the sample 20. In the view of FIG. 1, the X-ray source 12 and the shutter 14 have been rotated by 90° about the optical axis 30 of the spectrometer 10 to better illustrate their structure. The spectrometer 10 shown in FIG. 1 has a compact tabletop design and is transportable for in-situ analysis. The samples may be provided in a wide range of physical forms, including solids, powders, pressed pellets, liquids, granules, films and coatings. The typical element detection capabilities of the spectrometer 10 under atmospheric conditions range from aluminum (Al) to uranium (U). The spectrometer 10 allows for a qualitative and quantitative elemental analysis down to very low elemental concentrations and sample sizes of 20 μm. Like conventional X-ray tubes, the X-ray source 12 includes a cathode 32 to emit electrons and an anode 34 to collect the electrons emitted by the cathode 32. Thus, a flow of electrical current is established as the result of a high voltage connected across the cathode 32 and the anode 34. The electron flow within the X-ray source 12 is focussed onto a very small spot (the “hot spot”) 36 on the anode 34. The anode 34 is precisely angled at typically 5 to 15 degrees off perpendicular to the electron current so as to allow the escape of some of the X-rays generated at the “hot spot” 36 upon annihilation of the kinetic energy of the electrons colliding with the anode 34. The X-ray beam 26 thus generated is emitted from the “hot spot” 36 essentially perpendicular to the direction of the electron current and essentially along the optical axis 30 at diverging angles. The X-rays emitted from the X-ray source 12 first pass the shutter 14 attached to a housing 38 of the X-ray source 12. The shutter 14 selectively blocks the X-ray beam 26 generated within the X-ray source 12 and thus provides a control mechanism for selectively switching the Irradiation of the sample 20 “on” or “off”. The positioning/shielding module 16 is arranged downstream (in relation to X-ray source 12) of the shutter 14 and is rigidly attached to the shutter 14 by means of an interface member (not shown in FIG. 1). The positioning/shielding module 16 includes an X-ray shielding component 40, a positioning component 42 for the X-ray lens 28, and a lens mounting component 44 for rigidly coupling the X-ray lens 28 to the positioning component 42. The individual components 40, 42, 44, which are shown only schematically in FIG. 1, are illustrated in more detail in the various views of FIGS. 2 to 6. As becomes apparent from FIGS. 3 to 6, the X-ray shielding component 40 has an outer flange 46 with two screw holes 48 for rigidly attaching the entire positioning apparatus 16 to the shutter 14 (and thus to the X-ray source 12). The outer flange 46 therefore serves as an interface member of the positioning/shielding module 16 in relation to the shutter 14/the X-ray source 12. The X-ray shielding component 40 further comprises structural elements for limiting the X-ray beam essentially to an inlet opening of the X-ray lens 28. These structural elements will be described in more detail below. The X-ray lens (not shown in FIGS. 2 to 6) is fixedly mounted in a tube member 50. The tube member 50 in turn is rigidly coupled to the lens mounting component 44. The lens mounting component 44 comprises a base member 52 attached to the positioning component 42. The base member 52 has a central opening for receiving the tube member 50. A plurality of tongues 54 with outer threaded portions 56 extend from the opening of the base member 52 and in the axial direction of the tube member 50. The lens mounting component 44 further comprises a collar member 58 with a central opening through which the tube member 50 extends. The collar member 58 can be screwed onto the tongues 54 and cooperates with their outer threaded portions 56. Be means of an additional screw (not shown) extending in perpendicular to the tube member 50 and through the collar member 58, the free end of at least one of the tongues 54 can be moved towards the tubular member 50 as the screw is screwed into the collar member 58. Accordingly, a clamping connection between the tubular member 50 on the one hand and the lens mounting component 44 on the other hand is established. The positioning component 42 is arranged upstream of the lens mounting component 44 and includes two translation stages 60, 62 as well as two goniometer stages 64, 66. As can be seen from FIG. 2, the base member 52 of the lens mounting means 44 is attached to the bottom of the first translation stage 60. The individual positioning stages 60, 62, 64, 66 are arranged one behind the other. Starting with a first translation stage 60 as the most downstream positioning stage, a second translation stage 62, a first goniometer stage 64 and a second goniometer stage 66 as the most upstream positioning stage follow. Each of the positioning stages 60, 62, 64, 68 has a central X-ray passage 68, 70, 72, 74, respectively, through which the tubular member 50 extends. In combination, the first translation stage 60 and the second translation stage 62 form an xy translation stage. Accordingly, the first translation stage 60 has a first axis of translation, namely the x axis, which in FIG. 2 runs perpendicular to the axis of the tubular member 50 and in parallel to the drawing plane. The second translation stage 62 has a second axis of translation, namely the y axis which runs perpendicular to the x axis and perpendicular to the axis of the tubular member 50. By means of respective knobs, the first and second translation stage 60, 62 can be actuated independently from each other. In an alternative embodiment not shown in the drawings, a third translation stage having a third axis of translation (z axis) that runs perpendicular to both the first and second axis of translation may be provided. The two goniometer stages 64, 66 are arranged upstream of the two translation stages 60, 62. In their combination, the first goniometer stage 64 and the second goniometer stage 66 form a theta-phi goniometer that provides for two independent rotations about a common centre of rotation. This common centre of rotation is substantially constituted by the “hot spot” 36 shown in FIG. 1, i.e. by the X-ray emitting portion of the X-ray source 12. An actuation of the first goniometer stage 64 tilts the tube member 50 (with the X-ray lens) about a first tilting axis that runs through the “hot spot” 36 shown in FIG. 1 and in the drawing plane of FIG. 1 perpendicular to the optical axis 30. An actuation of the second goniometer stage 66 tilts the tube member 50 about a second tilting axis that also runs through the “hot spot” 36 and that is perpendicular to both the first tilting axis and the drawing plane of FIG. 1. The X-ray shielding component 40 is attached to the upstream end of the second translation stage 66 via screws extending through openings 92 in the flange portion 46 (FIG. 4). The shielding component 40 is configured to block all X-rays outside the circular X-ray passage defined by the upstream (Inlet) opening 90 of the tubular member 50 and thus efficiently shields the positioning component 42 from X-rays. Accordingly, the individual components of the positioning component 42 (such as the translation stages 60, 62 and the goniometer stages 64, 66) can without any X-ray safety problem be manufactured from conventional materials (such as aluminium) which generally are transparent or nearly transparent to X-rays. The construction of the X-ray shielding component 40 will now be described with particular reference to FIGS. 2, 5 and 6. In the embodiment, the X-ray shielding component 40 includes three separate members, namely a stationary member 94 and two movable shielding members 96, 98. The stationary member 94 and the shielding members 96, 98 are made from an X-ray shielding material such as steel. The stationary member 94 is integrally formed with the flange 46 and has a pot shape with a central circular aperture 100 in its bottom (FIG. 2). The stationary member 100 forms a housing for the two shielding members 96, 98. Each of the two shielding members 96, 98 is disc-shaped and has a central circular opening 102, 104. The shielding members 96, 98 are arranged one behind the other within the housing defined by the stationary member 94. The outer diameter of the downstream shielding member 98 is larger than the outer diameter of the upstream shielding member 96. Moreover, the diameter of the opening 104 of the downstream shielding member 98 is larger than the diameter of the opening 102 of the upstream shielding member 96. The tube member 50 extends trough the openings 102, 104 of the shielding members and through the aperture 100 of the stationary member 94. The diameter of the opening 102 of the upstream shielding member 96 essentially corresponds to the outer diameter of the tube member 50. The upstream shielding member 96 is mounted on the tube member 50 by means of a press fit connection. The press fit is not completely rigid, so that the axial position of the upstream shielding member 96 in relation to the tube member 50 can be adjusted. The diameter of the central opening 104 of the downstream shielding member 98 is substantially larger than the outer diameter of the tube member 50. Accordingly, the downstream shielding member 98 is only loosely coupled to the tube member 50 and is movable in a radial direction relative to the tube member 50. The outer diameters of the shielding members 96; 98 as well as the diameters of the respective openings 102, 104 and of the aperture 100 of the stationary member 94 are chosen such that the shielding members 96, 98 may in each position relative to the stationary member 94 completely cover the aperture 100 in an area outside the X-ray passage defined by the inlet opening 90 of the tube member 50. This can be seen in FIGS. 4 and 6. The movement of the shielding members 96, 98 in relation to the stationary member 94 is guided by a guiding mechanism that includes the inner rim 106 of the pot-shaped stationary member 94, the outer rim 108 of the downstream shielding member 98, the outer surface of the tube member 50, and the rim 112 of the aperture 100. The guiding mechanism ensures that none of the shielding members 96, 98 can be moved (by an actuation of the positioning component 42) to a position where the aperture 100 is not covered in an area surrounding the inlet opening 90 of the tube member 50. To this end, the outer rim 108 of the shielding member 98 cooperates with the inner rim 106 of the stationary member 94, and the outer surface of the tube member 50 annular cooperates with the inner rim 112 of the aperture 100. Accordingly, the tube member 50 can arbitrarily be positioned (by means of the positioning component 42, which thus “actuates” the shielding member 40) without any X-ray safety problem resulting from X-rays passing through the aperture 100 outside the inlet opening 90. Moreover, the individual parts of the positioning component 42 can be manufactured without any X-ray safety problem from aluminium which is transparent to X-rays. While the current invention has been described with respect to a particular embodiment, those skilled in the art will recognize that the current invention is not limited to the specific embodiment described and illustrated herein. Therefore, it is to be understood that the present disclosure is only illustrative. It is intended that the invention be limited only by scope of the claims appended hereto.
	abstract	Using the hierarchy cell5, cell51, cell52, cell4 of the figure cells in the design pattern data, it is not necessary to take the actual forms of patterns and the arrangement information of data (relation between patterns, period of arrangement) into consideration, and therefore, characters for CP exposure can be extracted effectively.
059329300	summary	FIELD OF THE INVENTION This invention generally relates to fissionable fuel material for use in nuclear reactors. In particular, the invention is directed to an improvement in the process for fabricating mixed-oxide fuel for a nuclear reactor. BACKGROUND OF THE INVENTION The need to dispose of plutonium derived from the dismantlement of nuclear weapons is a serious problem. One step which can be taken to alleviate this problem is to recycle weapons-grade plutonium as fuel for a nuclear reactor power plant. This solution requires that the plutonium be transported from the weapons site to the fuel fabrication facility. However, this prospect raises the concern about the best method for plutonium shipment and storage from both the safety and diversion standpoints. Historically, plutonium has been shipped as the metal, nitrate or oxide. The metal form must be shipped within an inert atmosphere to prevent oxidation. In a postulated accident, the plutonium metal would be difficult to disperse into the environment because of its dense form. However, if the plutonium metal comes into contact with air, it can oxidize or burn and thus form the oxide. The oxide is a fine powder which could be readily dispersed into the environment. Furthermore, plutonium metal is ideal for fabrication of nuclear weapons and is thus highly susceptible as a target for diversion. The nitrate is a liquid which is slightly more resistant to diversion but can be easily dispersed into the environment in the event that the storage container is breached during an accident or act of sabotage. The oxide is generally shipped as a fine powder which is more resistant to diversion than is the liquid nitrate. However, the oxide can also be easily dispersed into the environment if the storage container breaks open during an accident or act of sabotage. Thus, there is a need for a safe and secure method for transporting weapons-grade plutonium to the fuel fabrication facility. Previous mixed-oxide fuel fabrication has relied on fine plutonia feed powders usually converted from plutonium nitrate solutions to the oxide by direct precipitation processes or as a co-precipitated compound with uranium. These conversion processes result in a very fine powder that is blended with urania to produce mixed-oxide feed material. In some cases, this blended material has been milled by a high-energy process to improve the plutonium dispersion. Statistical sampling and metallographic examination techniques are utilized to qualify each powder blend. One hundred percent inspection techniques are utilized to verify that gross plutonium dispersion did not occur in any portion of a completed fuel rod. SUMMARY OF THE INVENTION The present invention is a process for fabricating weapons-grade plutonium into mixed-oxide fuel for use in a nuclear reactor. The plutonium is converted into plutonia powder at a site remote from the fuel fabrication facility and then the plutonia powder is pressed and fired into high-density plutonia pellets for transport to the fuel fabrication facility. Since the pellets are relatively insoluble, it is difficult to separate the plutonium from the high-density pellets which serve as a diversion-resistant and environmentally sound method of shipping the plutonia for use as a feed material. Plutonia in pellet form provides the greatest fabrication challenge from the standpoint of plutonium homogeneity. Comminution methods must be employed to reduce the plutonia pellets to a fine powder for blending with urania feed to produce mixed oxide acceptable for reactor operation. In this process the plutonia pellets are ground into a fine powder and screened to segregate the fines. The fines are blended with urania to form a mixed-oxide powder blend which can be fabricated into fuel pellets by standard techniques. Since the fine plutonia powder produced by comminution methods does not tend to agglomerate like powder produced by chemical processes, a homogeneous blend of mixed oxide can be more easily produced.
047042460	claims	1. In the replacement of an old split-pin assembly of the guide tube of a nuclear reactor by a new split-pin assembly, said new split-pin assembly including a new split pin and a new nut securing the new split pin to the guide tube, said new nut having a locking cap to be crimped to said new split pin, said new split-pin assembly being positioned to be processed, a method of crimping said locking cap to said new split pin, the said method being practiced with a crimping mechanism and a support for supporting said crimping mechanism, said support being in retracted position in its standby state, the said method including, advancing said support from said retracted position to an intermediate position, said support being so advanced in a first general direction, generally defined by a first plane, thereafter advancing said support in a second general direction, defined by a second plane generally transverse to said first plane, to set said crimping mechanism, relative to said positioned split-pin assembly, in position to crimp said locking cap to said new split pin, and thereafter actuating said crimping mechanism to crimp said locking cap to said new split pin. 2. The method of claim 1 practiced with a cylinder having a piston connected to the support and moveable by the cylinder, the said method including the step of moving the piston linearly continuously from a first position to a second position to advance the support both in the first general direction and in the second general direction. 3. The method of claim 1 practiced with a crimping mechanism having crimping jaws normally set in non-crimping setting, wherein the support in being advanced in the second general direction sets the crimping mechanism with crimping jaws in the non-crimping setting in a position in which the crimping jaws encompass the locking cap. 4. The method of claim 3 practiced with a crimping mechanism wherein the crimping jaws have cam surfaces and cam-follower rollers moveable cooperatively along said surfaces to set said crimping jaws selectively in non-crimping or crimping setting, said method including the step, to be carried out while the jaws encompass the locking cap in non-crimping setting, of moving said cam-follower rollers to set said crimping jaws in crimping setting. 5. The method of claim 1 practiced with the support in retracted vertical position in the standby state, wherein the first plane is generally vertical and the second plane is generally horizontal. 6. The method of claim 1 practiced with the support locked in retracted position by a latch, the said method including the step of unlocking said latch preparatory to advancing said support from said retracted position to the intermediate position. 7. The method of claim 1 practiced with a crimping mechanism having a surface which matches the external surface of the nut of the new split-pin assembly, wherein when the crimping mechanism is set in position to crimp the locking cap by advancing the support in the second direction, said surface of said crimping mechanism is seated in engagement with said external surface of said nut.
044219881	summary	BACKGROUND OF THE INVENTION This invention relates to charged particle beam scanning of a workpiece and, more particularly, to a method of and apparatus for highly efficient, highly uniform ion beam scanning of a workpiece, such as a semicondutor wafer. Ion implantation has become a standard technique for introducing impurities into semiconductor wafers in a controlled and rapid manner. A beam of ions is generated in a source and directed with varying degrees of acceleration toward the semiconductor wafer. The impurities are introduced into the bulk of semiconductor wafers by using the momentum of the ions as a means of embedding them in the crystalline lattice of the semiconductor material. Uniformity of impurity concentration over the surface of the semiconductor wafer is of utmost importance in semiconductor processing. In addition, one of the major objectives in commercial semiconductor processing is to achieve a high throughput in terms of wafers processed per unit time. One way to achieve high throughput is to simultaneously process a number of wafers in a batch. Such systems typically involve mechanical movement of wafers in relation to a beam which is scanned in one dimension. Batch processing systems, however, are generally large to accommodate the batches and are generally used only for high dose implantations. In addition, throughput is less than optimum because of the time required to manually change batches. Furthermore, if the processing system experiences a problem, large numbers of expensive semiconductor wafers can be destroyed. Another approach has been to process wafers one at a time and to employ automatic wafer handling to improve throughput. The wafer is typically held stationary and the ion beam is electrostatically scanned in a two dimensional pattern over its surface. Such a pattern is disclosed in U.S. Pat. No. 4,283,631 issued Aug. 11, 1981 to Turner. Constant amplitude scanning signals are applied to x and y deflection plates to deflect the ion beam in a square Lissajous pattern. The scanning signals are scaled in amplitude to insure that the square pattern covers the round semiconductor wafer. (Wafers typically have one flat edge, but for present purposes this can be ignored.) In addition, the dimension of the square pattern is made slightly larger than the diameter of the wafer to provide a certain amount of overscan. Overscan is necessary to avoid nonuniformities in the doping of the wafer when the beam reverses direction after each scan line and to allow for variations in wafer diameter and position. Furthermore, as the cross-sectional dimension of the ion beam increases, the amount of overscan must be increased to insure that the beam is entirely off the wafer before it is reversed. It can be seen that time spent by the system in scanning the corners of the square pattern outside the periphery of the wafer is unproductive in terms of ion implantation and reduces system throughput. In typical prior art systems, the time spent by the system in scanning portions of the pattern outside the periphery of the semiconductor wafer has been as much as 30% of the total scanning time. An arrangement for reducing wasted scanning time and confining the scan pattern to the general shape of a circle is disclosed in U.S. Pat. No. 4,260,897, issued Apr. 7, 1981 to Bakker et al. Semicircular conductive elements placed on opposite sides of the wafer detect the ion beam when it scans off the wafer and cause reversal of the scan direction. However, such an arrangement adds complexity to the system. Furthermore, the detector elements are subject to degradation by the ion beam and must be changed to correspond to the size of the semiconductor wafer being processed. It is a general object of the present invention to provide a new and improved method of and apparatus for scanning a charged particle beam over a workpiece. It is another object of the present invention to provide a method of and apparatus for scanning a charged particle beam over a workpiece in a highly efficient pattern. It is yet another object of the present invention to provide a method of and apparatus for scanning a charged particle beam over a workpiece in a highly uniform pattern. It is still another object of the present invention to provide a method of and apparatus for scanning a charged particle beam over a workpiece in a pattern which enhances the speed with which workpieces are processed. It is a further object of the present invention to provide a method of and apparatus for scanning a charged particle beam over a workpiece in a pattern corresponding in shape to the shape of the workpiece. It is a further object of the present invention to provide a method of and apparatus for scanning a charged particle beam over a workpiece in a pattern which is selectable in size to correspond to the size of the workpiece. SUMMARY OF THE INVENTION According to the present invention, these and other objects and advantages are achieved in apparatus for scanning a charged particle beam over a workpiece. The apparatus comprises first deflection means for deflection of the beam in response to a first scanning voltage and means coupled thereto for generating the first scanning voltage. The first scanning voltage includes alternating positive ramp portions and negative ramp portions and transitions therebetween. The positive and negative ramp portions are controllable in time duration. The apparatus further comprises second deflection means for deflection of the beam in response to a second scanning voltage and means coupled thereto for generating the second scanning voltage. The first and the second deflection means are operative to deflect the beam in mutually perpendicular directions. The second scanning voltage remains constant during the positive and negative ramp portions and is incremented at the time of the transitions between ramp portions. The apparatus still further includes means for controlling the time durations of the positive and negative ramp portions according to a series of predetermined time durations so as to provide a scan pattern corresponding in size and shape to the size and shape of the workpiece. According to another aspect of the present invention, there is provided a method for scanning a charged particle beam over a workpiece in a charged particle beam irradiation system of the type including first deflection means and second deflection means operative to deflect the beam in mutually perpendicular directions in response to voltages applied thereto. The method comprises the steps of generating a first scanning voltage which includes alternating positive ramp portions and negative ramp portions and transitions therebetween and applying the first scanning voltage to the first deflection means. The positive and negative ramp portions are controllable in time duration. The method further comprises the steps of generating a second scanning voltage, which remains constant during the positive and negative ramp portions and which is incremented at each of the transitions between ramp pportions, and applying the second scanning voltage to the second deflection means. The method still further comprises the step of controlling the durations of the positive and negative ramp portions according to a predetermined sequence so as to provide a scan pattern corresponding in size and shape to the size and shape of the workpiece.
	summary
054810612	summary	TECHNICAL FIELD The present invention relates to a method of solidifying industrial wastes and solid bodies. More particularly, the present invention is concerned with a method of solidifying industrial wastes which comprises solidifying hazardous industrial wastes, such as a radioactive waste, with hydraulic materials, such as cement, so as to render them suitable for storage and solid bodies obtained thereby. BACKGROUND ART As is well known, it is necessary in order to ensure stable storage and disposal of industrial wastes, such as radioactive wastes, generated in radioactive substance handling facilities, such as a nuclear power plant, that such wastes should be solidified by Packing them together with a solidifying material into a container, thereby preventing hazardous substances, such as radioactive substances, from diffusing into the environment. Examples of the solidification method include one in which use is made of a solidifying material such as cement, asphalt, thermoplastics, thermosetting plastics, water glass, or the like. Although all of these solidifying materials are satisfactory from the viewpoint of attaining the object of preventing radioactive substances from diffusing into the environment, differences arise in the handling characteristics and the amount of packing of the waste according to the properties of each of them. Among these solidifying materials, cement has advantages that (1) it is an inorganic material and therefore exhibits high fire resistance, (2) it is hardenable at ordinary temperatures, and (3) it is generally used and therefore stable supply thereof is ensured. However, for the following reasons, the cement has a problem that there is a limitation to the amount of packing of the waste. That is, a solidifying material comprising cement gives rise to voids as the result of shrinkage accompanying hardening. For details of this shrinkage of cement, reference may be made to A. M. Neville: "Properties of Concrete", 1977 published by Pitman Publishing Limited, (translation by Goto and Osaka published by Gihodo Publishing Co., Ltd. on Nov. 30, 1979). According to this literature, hardened cement consists of gel particles of hydrated cement, gel voids (gel pore) constituted of minute gaps formed among said gel particles, and capillary voids (capillary cavity) formed among agglomerates constituted of said gel particles and said gel voids. When water is mixed with cement at a water to cement ratio of 0.5, 60 ml of water and 40 ml of the cement are present in 100 ml of the resultant mixture. With the progress of hardening of the cement, however, the mixture comes to consist of 61.6 ml of hydrated cement gels, 24.0 ml of gel voids, and 14.4 ml of capillary voids. The gel voids are filled with water generally known as "gel water". Under normal conditions, there is no chance for this water to be removed. Consequently, only capillary voids remain as space and account for as much as 14% of the whole. When such voids are present, there occurs a problem that an increase in the amount of packing of the waste is accompanied by an increase in radioactivity leaching rate. Accordingly, known use of a cement solidifying material has had a drawback that the amount of packing of the waste cannot be increased because otherwise the radioactivity leaching rate will increase. Examples of the radioactive wastes include those obtained in a boiling water reactor power plant (hereinafter referred to as "BWR plant") of which the major components are sodium sulfate and an ion exchange resin. All of these wastes exhibit water absorptivity. That is, sodium sulfate exhibits water absorptivity through formation of a hydrate and subsequent dissolution thereof. On the other hand, the ion exchange resin exhibits water absorptivity since it has hydrophilic ion exchange groups. When radioactive wastes are to be solidified with hydraulic materials, such as cement, the added water is absorbed by the water-absorptive radioactive wastes since they contain water-absorptive substances as described above. Further, when the amount of packing of the waste is large, the fluidity necessary for hardening the cement cannot be maintained, which makes solidification impossible. In the above-described known cement solidification technique, no attention has been paid to two factors, i.e., capillary voids generated after hardening and viscosity increase of a water/cement mixture caused by water-absorptive radioactive wastes. Consequently, the known technique has had a drawback that the amount of packing of the waste cannot be increased. Disclosure of Invention: An object of the present invention is to provide a solidification method in which the radioactivity leaking rate of the wastes, e.g., radioactive wastes, incorporated in solid bodies can be decreased by reducing the volume of capillary voids even when the amount of packing of the waste is increased. Another object of the present invention, in addition to the above, is to enable the water/cement mixture to keep its viscosity below a predetermined value even when the amount of packing of the waste is increased in solidifying water-absorptive wastes with a water/cement mixture. The above-described objects of a method of solidifying industrial wastes with cement can be attained by mixing the industrial wastes with cement which is substantially non-shrinkable or expansible with respect to volume change upon hardening, and then hardening the cement, thereby forming solid bodies. It is preferred that the cement be hardened after addition of a hydrophilic material to the cement. The use of cement capable of generating expansible substances, such as ettringite, i.e., non-shrinkable or expansible cement for hardening, leads to formation of compact solid bodies having voids, such as capillary voids, of reduced volume, thereby enabling the radioactivity leaching rate to be decreased. Moreover, since no shrinkage accompanies hardening, no tensile stress occurs in the cement surrounding minute waste particles in the solid bodies, thereby enabling a reduction in the mechanic air, strengths (cracks etc.) of the solid bodies to be minimized. In addition, the capability of limiting the radioactivity leaking and the decrease in the mechanical strengths as described above enables the amount of packing of the waste to be increased. Further, prior addition of a hydrophilic material enables the cement fluidity before hardening to be maintained even after complete absorption of water by water-absorptive radioactive wastes. This is extremely advantageous in carrying out hardening.
	claims	1. A device for attenuating an electromagnetic pulse generated in an installation wherein a high-power laser beam is sent to a target mounted on a target support, comprising:an electrically conductive plate, electrically connected to an electrical earth of the installation and to which the target support is fixed;a plate of material which absorbs electromagnetic waves fixed to one face of the electrically conductive plate located on the target support side; andmeans for passing a discharge current which is the result of an interaction of the laser beam with the target between the target and the electrically conductive plate, wherein the means for passing the discharge current are equipped with means for attenuating said current. 2. The device according to claim 1, wherein the means for passing the discharge current comprise an electrically conductive element mounted in series with a current limiting resistance, wherein the electrically conductive element mounted in series with the current limiting resistance constitutes the target support. 3. The device according to claim 1, wherein the means for passing the discharge current comprise an electrically conductive element mounted in series with an inductance, wherein the electrically conductive element mounted in series with the inductance constitutes the target support. 4. The device according to claim 1, wherein the means for passing the discharge current are made up of an electrically conductive element and the means for attenuating the current are made up of an element of material which absorbs a magnetic field which surrounds the electrically conductive element, wherein the electrically conductive element surrounded by the material which absorbs the magnetic field forms the target support. 5. The device according to claim 1, wherein the means for passing the discharge current are made up of an electrically conductive element mounted in series with a current limiting resistance and with an inductance, wherein the electrically conductive element mounted in series with the resistance and the inductance constitutes the target support. 6. The device according to claim 5, wherein an element of material which absorbs a magnetic field surrounds the electrically conductive element. 7. The device according to claim 1, wherein the target support is made of an electrically insulating material and the means for passing the discharge current comprise an electrically conductive part mounted in series with a current limiting resistance, a first end of the electrically conductive part being linked to the target and a second end of the electrically conductive part being fixed to the electrically conductive plate, in an opening made in the plate of material which absorbs electromagnetic waves. 8. The device according to claim 1, wherein the target support is made of an electrically insulating material and the means for passing the discharge current comprise an electrically conductive part mounted in series with an inductance, a first end of the electrically conductive part being linked to the target and a second end of the electrically conductive part being fixed to the electrically conductive plate, in an opening made in the plate of material which absorbs electromagnetic waves. 9. The device according to claim 1, wherein the target support is made of an electrically insulating material, the means for passing the discharge current comprise an electrically conductive part, a first end of the electrically conductive part being linked to the target and a second end of the electrically conductive part being fixed to the electrically conductive plate, in an opening made in the plate of material which absorbs electromagnetic waves and the means for attenuating the current are made up of an element of material which absorbs a magnetic field which surrounds the electrically conductive part. 10. The device according to claim 1, wherein the target support is made of an electrically insulating material and the means for passing the discharge current comprise an electrically conductive part mounted in series with a current limiting resistance and an inductance, a first end of the electrically conductive part being linked to the target and a second end of the electrically conductive part being fixed to the electrically conductive plate, in an opening made in the plate of material which absorbs electromagnetic waves. 11. The device according to claim 10, wherein an element of material which absorbs a magnetic field surrounds the electrically conductive part. 12. The device according to claim 1, wherein the material which absorbs the electromagnetic waves is a ferrite. 13. The device according to claim 4, wherein the material which absorbs the magnetic field is a ferrite. 14. The device according to claim 6, wherein the material which absorbs the magnetic field is a ferrite. 15. The device according to claim 9, wherein the material which absorbs the magnetic field is a ferrite. 16. The device according to claim 11, wherein the material which absorbs the magnetic field is a ferrite. 17. The device according to claim 1, wherein a plate of electrically insulating material covers a face of the electrically conductive plate located on the side opposite the target support.
	description	The present invention relates to a containment vessel and a nuclear power plant provided with the containment vessel. As a representative example of a conventional boiling water reactor (BWR), which has been put into practical use, there is known an advanced BWR (ABWR). Hereinafter, an outline of structures of a containment vessel and the like of the ABWR will be described with reference to FIG. 6 (see Patent Document 1, etc.) In FIG. 6, a core 1 is accommodated inside a reactor pressure vessel (RPV) 2. A containment vessel (CV) 3 includes a cylindrical side wall (tubular side wall) 4, a top slab 5 closing an upper portion of the cylindrical side wall 4, a containment vessel head 6 provided at a center portion of the top slab 5, and a base mat 7 supporting the above components and closing a lower portion of the cylindrical side wall 4. The above components are designed so as to withstand a pressure rise upon occurrence of a design basis accident and constitute a pressure boundary. An inner space of the containment vessel 3 is partitioned into a dry well (DW) 8 accommodating the reactor pressure vessel 2 and a suppression chamber (wet well) (WW) 9. The reactor pressure vessel 2 is supported by a vessel support 10 through a vessel skirt 11. A part of a space inside the dry well 8 above the vessel skirt 11 is referred to as an upper dry well 12, and a part of the space inside the dry well 8 below the vessel skirt 11 is referred to as a lower dry well 13. The suppression chamber 9 is installed so as to circumferentially surround the lower dry well 13 and has, inside thereof, a suppression pool (ST) 14. The dry well 8 and the suppression pool. 14 are connected to each other by vent pipes 15. The dry well 8 and the wet well 9 have an integral structure having a cylindrical shape to constitute the containment vessel 3. A horizontal floor separating the dry well 8 and the wet well 9 from each other is referred to as a diaphragm floor 16. The containment vessel 3 has a design pressure of 3.16 kg/cm2 in gauge pressure. The cylindrical side wall 4 and the top slab 5 are formed of reinforced concrete with thicknesses of about 2 m and about 2.4 m, respectively. Inner surfaces of the cylindrical side wall 4 and the top slab 5 are each lined with a steel liner (not illustrated) for the purpose of suppressing leakage of radioactive materials. The base mat 7 is formed of reinforced concrete with a thickness of about 5 m. In FIG. 6, an edge line of the cylindrical side wall 4 representing a joint part between the cylindrical side wall 4 and the top slab 5 is extended to a topmost potion of the containment vessel 3 for making a boundary therebetween easy to understand. Actually, there may be a case where the top slab 5 is placed on the cylindrical side wall 4. Alternatively, since both the cylindrical side wall 4 and the top slab 5 are formed of reinforced concrete, there may be a case where the joint part between the cylindrical side wall 4 and the top slab 5 constitutes a common part (continuous structure) to make the boundary obscure. The containment vessel in which the primary structures are formed of reinforced concrete is generally referred to as RCCV. The containment vessel head 6 is formed of a steel so as to be capable of being removed upon refueling. Recently, there exists a type in which a water shield pool (not illustrated) is arranged above the containment vessel head 6. Further, recently, there exists a type in which a cooling water pool (not illustrated) of a passive safety system is arranged above the top slab 5. A design leak rate of the containment vessel 3 is about 0.5%/day In recent years, a plan is being studied in which the cylindrical side wall 4 and the top slab 5 are each not formed of the reinforced concrete but of a steel concrete composite (SC composite). The SC composite is obtained by filling concrete between two steel plates. The use of the SC composite eliminates the need of laying rebar and allows module construction. There is known, as an example in which the SC composite is adopted to a nuclear power plant, a shield building of AP1000 made by Toshiba/Westinghouse. Patent Document 1: Japanese Patent Application Laid-Open Publication No. 2004-333357 It is widely admitted today that, of all the radioactive materials released from the core upon occurrence of a design basis accident, particulate radioactive materials cause most serious radiation exposure damage to environment. Above all, particulate radioactive iodine inflicts maximal damage. The particulate radioactive materials have high water solubility and are thus difficult to leak from a water sealed portion. It is appreciated that radioactive noble gas and the like diffuse in the atmosphere even if they leak at a design leak rate to contribute less to the radiation exposure. Therefore, in order to reduce exposure dose upon occurrence of a design basis accident, it is important to minimize leakage of the particulate radioactive materials. A conventional ABWR has a structure in which water is pooled above the top slab and the containment vessel head, so that even if a design basis accident occurs to cause the particulate radioactive materials to be released inside the containment vessel, the released particulate radioactive materials are difficult to leak. Further, storage of pool water in the suppression pool makes it difficult for the particulate radioactive materials to leak. Furthermore, upon occurrence of a design basis accident, coolant flowing out from the reactor pressure vessel is pooled in the lower dry well, so that the particulate radioactive materials are difficult to leak from the lower dry well. Thus, it is the particulate radioactive materials leaking to environment through the tubular side wall having no water sealing effect that increase the exposure dose. In particular, a number of penetrations for electric systems or piping are formed in the cylindrical side wall and, actually, the leakage through the cylindrical side wall accounts for the most part of the design leak rate of the containment vessel. Thus, in order to reduce the exposure dose upon occurrence of a design basis accident, it is necessary to prevent the particulate radioactive materials leaking through the cylindrical side wall from being released to environment. The conventional ABWR is designed to apply filtering to the particulate radioactive materials upon occurrence of a design basis accident by using a standby gas treatment system (not illustrated). However, a loss of power may occur under actual severe accident conditions to stop the standby gas treatment system, so that there is a possibility that an excessive amount of the particulate radioactive materials are released to environment. Further, under severe accident conditions, a large amount of hydrogen is generated from core fuel by metal-water reaction, with the result that an internal pressure of the containment vessel 3 rises to a design pressure or more (about double the design pressure). More specifically, non-condensable gases such as a large amount of hydrogen generated from the core fuel and nitrogen existing before occurrence of the accident pass through the vent pipes 15, accompanied by steam in the dry well 8 to the suppression pool 14 where the non-condensable gases are pushed into a gas phase of the wet well 9 to be compressed, causing the internal pressure of the containment vessel 3 to rise. A pressure of the steam in the dry well 8 is slightly higher than the pressure caused by the compression of the non-condensable gases in the gas phase of the wet well 9. Under such a high-pressure condition, there is a possibility that leakage from the containment vessel 3 exceeds the design leak rate. An object of the present invention is to suppress, without relying on an external power source, the particulate radioactive materials from being released to environment upon occurrence of a reactor accident and to restrict an internal pressure of the containment vessel to a design pressure or less for ensuring safety. In order to achieve the object, according to an aspect of the present invention, there is provided a containment vessel comprising: a horizontally-extending base mat supporting a load of a reactor pressure vessel accommodating a core; an inner shell disposed on the base mat so as to gas-tightly cover the reactor pressure vessel; and an outer shell disposed on the base mat so as to horizontally cover an outer periphery of the inner shell in an gas-tight manner, the inner shell including: a first cylindrical side wall having a lower end connected to the base mat and an upper end located higher than at least an upper end of the core and horizontally surrounding a periphery of the reactor pressure vessel; a containment vessel head covering an upper portion of the reactor pressure vessel; a first top slab gas-tightly connecting a periphery of the containment vessel head and an upper end portion of the first cylindrical side wall; a dry well constituting a part of the first cylindrical side wall and accommodating the reactor pressure vessel; and a wet well constituting a part of the first cylindrical side wall and accommodating a suppression pool connected to the dry well through a vent pipe, the outer shell including: a second cylindrical side wall having a lower end connected to the base mat and surrounding an outer periphery of the first cylindrical side wall; a second top slab gas-tightly connecting an upper end of the second cylindrical side wall and the inner shell; and an outer well which is a space gas-tightly surrounded by the second cylindrical side wall, the second top slab, and the base mat. According to another aspect of the present invention, there is provided a nuclear power plant comprising a containment vessel including: a horizontally-extending base mat supporting a load of a reactor pressure vessel accommodating a core; an inner shell disposed on the base mat so as to gas-tightly cover the reactor pressure vessel; and an outer shell disposed on the base mat so as to horizontally cover an outer periphery of the inner shell in an gas-tight manner, the inner shell including: a first cylindrical side wall having a lower end connected to the base mat and an upper end located higher than at least an upper end of the core and horizontally surrounding a periphery of the reactor pressure vessel; a containment vessel head covering an upper portion of the reactor pressure vessel; a first top slab gas-tightly connecting a periphery of the containment vessel head and an upper end portion of the first cylindrical side wall; a dry well constituting a part of the first cylindrical side wall and accommodating the reactor pressure vessel; and a wet well constituting a part of the first cylindrical side wall and accommodating a suppression pool connected to the dry well through a vent pipe, the outer shell including: a second cylindrical side wall having a lower end connected to the base mat and surrounding an outer periphery of the first cylindrical side wall; a second top slab gas-tightly connecting an upper end of the second cylindrical side wall and the inner shell; and an outer well which is a space gas-tightly surrounded by the second cylindrical side wall, second top slab, and base mat. According to the present invention, the double confinement function allows the particulate radioactive materials released from the core fuel upon occurrence of the reactor accident to be confined in the containment vessel without relying on an external power source. Embodiments of the present invention will be described based on FIGS. 1 to 5. In FIGS. 1 to 5, the same reference numerals are given to the same or similar components as in FIG. 6, so a description thereof will be omitted and only the essential elements will be explained. [First Embodiment] A first embodiment of a containment vessel (CV) according to the present invention will be described with reference to FIG. 1. FIG. 1 is an elevational cross-sectional view illustrating a containment vessel according to the first embodiment of the present invention. The first embodiment of the present invention differs from the above conventional example in that a tubular side wall of a containment vessel 3 is doubled. More specifically, the tubular side wall is constituted by a first cylindrical side wall 4a, and a second cylindrical side wall 4b which is formed so as to surround the first cylindrical side wall 4a with a predetermined interval therebetween. Further, a second top slab 5b is installed so as to cover an upper portion of the second cylindrical side wall 4b. The second cylindrical side wall 4b and the second top slab 5b also constitute a pressure boundary, a design pressure of which is about 2.11 kg/cm2 to about 3.16 kg/cm2 in gauge pressure. An upper portion of the first cylindrical side wall 4a is covered by a first top slab 5a and a containment vessel head 6. A design pressure of this portion is about 3.16 kg/cm2 in gauge pressure. A structure constituted by the first cylindrical side wall 4a, first top slab 5a, containment vessel head 6, and a segment 7a of a horizontally-extending base mat 7 that is located directly below the first cylindrical side wall 4a, first top slab 5a, and the containment vessel head 6 is referred to as inner shell 17. On the other hand, a structure constituted by the second cylindrical side wall 4b, second top slab 5b, and a segment 7b of the horizontally-extending base mat 7 that is located directly below the second cylindrical side wall 4b and the second top slab 5b is referred to as outer shell 18. Further, a space surrounded by outer surfaces of the first cylindrical side wall 4a, second top slab 5b, and the second cylindrical side wall 4b and the part 7b of the base mat 7 that is located directly below the first cylindrical side wall 4a, second top slab 5b, and the second cylindrical side wall 4b is referred to as outer well 19. FIG. 1 illustrates a case where the second top slab 5b is located at the same height position as the first top slab 5a. Although FIG. 1 illustrates an example in which the first and second top slabs 5a and 5b are joined to the first cylindrical side wall 4a from both sides thereof, the joining method is not limited to this. For example, a joining method may be adopted in which the first and second top slabs 5a and 5b are joined to each other in a horizontal direction, and an upper end of the first cylindrical side wall 4a is connected to a lower portion of the joined top slabs 5a and 5b. Further, alternatively, the first and second top slabs 5a and 5b and the first cylindrical side wall 4a may be joined together such that the joint part therebetween constitute a continuous common part therebetween. An inner space of the inner shell 17 is partitioned into a dry well (DW) 8 accommodating a reactor pressure vessel (RPV) 2 and a wet well (suppression chamber, WW) 9. The reactor pressure vessel 2 is supported by a vessel support 10 through a vessel skirt 11. The vessel support 10 is supported by the base mat 7 through a cylindrical pedestal 30. That is, a load of the reactor pressure vessel 2 is finally supported by the base mat 7. Apart of a space inside the dry well 8 above the vessel skirt 11 is referred to as an upper dry well 12, and a part of the space inside the dry well 8 below the vessel skirt 11 is referred to as a lower dry well 13. The wet well 9 is installed so as to circumferentially surround the lower dry well 13 and has, inside thereof, a suppression pool (SP) 14. The dry well 8 and the wet well 9 are partitioned by a partition wall including a diaphragm floor 16. The dry well 8 and the suppression pool 14 are connected to each other by vent pipes 15. The dry well 8 and the wet well 9 constitute, as a whole, a cylindrical space surrounded by the first cylindrical side wall 4a. The first cylindrical side wall 4a serves as outer walls of the upper dry well 12 and the wet well 9. In the present embodiment, heights of the reactor pressure vessel 2 and the wet well 9 are slightly increased as compared to those of the conventional ABWR so that the upper end of the core 1 is located at the same height or lower than the diaphragm floor 16. A gas-phase vent pipe 20 connecting a gas phase portion of the wet well 9 and the outer well 19 is provided. An isolation and connection switching system (ICSS) 21 is provided at an inlet of the gas-phase vent pipe 20. The isolation and connection switching system 21 is configured to be closed during normal operation of the reactor and be opened upon occurrence of an accident. For example, as the isolation and connection switching system 21, a rupture disk, a vacuum break valve, and an automatic isolation valve are available. The rupture disk is designed to be actuated to break the disk-shaped partition plate arranged in a pipe and allow communication with the atmosphere when a predetermined pressure difference takes place, and does not have isolation or closure function after the actuation. In other words, atmosphere can flow forwardly or backwardly through the rupture disk depending on the pressure difference after the actuation. The vacuum break valve is a highly reliable gas-phase check valve. The vacuum break valve is designed to be actuated to allow communication with the atmosphere when a predetermined pressure difference takes place but become closed to shut off the flow path when the pressure difference becomes small. The atmosphere can flow forwardly through the vacuum break valve but not backwardly. It is typically used when the forward communication feature and the backward isolation feature need to be realized highly reliably. The automatic isolation valve is typically a motor-driven valve or pneumatically driven valve that is designed to be automatically opened and closed when a predetermined pressure difference takes place. It can be held to an open state and returned to a closed state after it is opened. If it is a motor-driven valve, it will take some time for actuation. If it is a pneumatically driven valve, it is actuated quickly but an accumulator is required. It is a matter of choice in a design phase which type of the isolation and connection switching system is to be selected. The functional feature that is common to the above-described types of isolation and connection switching system 21 is that they normally provide an isolated state but begin to allow the atmosphere to flow forwardly when a predetermined pressure difference takes place. In other words, any of the above-listed isolation and connection switching systems 21 provide an isolated state when the nuclear reactor is operating normally and the gas phase portion of the wet well 9 and the outer well 19 are separated. Additionally, the isolation and connection switching system 21 will maintain an isolated state if a transient or a small scale loss-of-coolant accident not accompanied by a pressure rise in the gas phase portion of the wet well 9 occurs. As a result, the transient or small scale loss-of-coolant accident can be confined to the inner shell 17. To this end, the first tubular side wall 4a does not have an opening portion other than the gas-phase vent pipe 20. On the other hand, when a large break loss-of-coolant accident or a severe accident occurs, the pressure of the gas-phase portion of the wet well 9 rises. When the pressure has risen to reach the pressure difference for actuating the isolation and connection switching system 21, the isolation and connection switching system 21 is opened, which brings the gas-phase portion of the wet well 9 and the outer well 19 into communication with each other. Then, as a result, the pressure rise in the inner shell 17 caused by the non-condensable gas, such as hydrogen and nitrogen, accumulated in the gas-phase portion of the wet well 9 is released into the inside of the outer shell 18, thereby significantly mitigating the pressure rise in the containment vessel 3. Further, a large amount of hydrogen is released to the inside of the containment vessel 3 upon occurrence of a severe accident, so that hydrogen detonation can take place if the atmosphere in the containment vessel 3 is air. In order to eliminate such a risk, the atmosphere inside the containment vessel 3, including the outer well 19, is replaced by nitrogen so as to be held in a state where oxygen concentration is lower than that of ordinary air. In the present embodiment, although not illustrated in FIG. 1, a fuel pool 27 (see FIG. 5) is arranged above the first and second top slabs 5a and 5b. Further, a water shield 28 (see FIG. 5) is arranged above the containment vessel head 6. In the present embodiment, it is possible to maintain the internal pressure of the containment vessel low upon occurrence of a severe accident. The volume of the free space in the outer well 19 is about four times the volume of the free space in the wet well 9. Therefore, the internal pressure of the containment vessel can be suppressed to a quarter of the conventional level at the severe accident. Thus, it is possible to easily reduce the pressure at the severe accident to the design pressure level or less. Further, according to the present embodiment, in the case of a small-scale accident where the isolation and connection switching system 21 is not opened, the radioactive materials are confined by the double confinement structure having the first cylindrical side wall 4a and the second cylindrical side wall 4b, thereby suppressing the radioactive materials from being released to environment. Further, in a case of an accident severe enough to open the isolation and connection switching system 21, the internal pressure of the inner shell 17 and that of the outer well 19 are equalized, with the result that a pressure difference between the inside and outside of the first cylindrical side wall 4a becomes negligible, thereby preventing the particulate radioactive materials floating in the dry well 8 from directly leaking through the first cylindrical side wall 4a. The particulate radioactive materials floating in the dry well 8 is guided to the inside of the suppression pool 14 through the vent pipes 15 to be dissolved in the suppression pool water, so that only a minute amount of the particulate radioactive materials are moved to the wet well gas phase portion. Then, the minute amount of the particulate radioactive materials are moved to the outer well 19 through the isolation and connection switching system 21 but are confined by the outer shell 18, thereby substantially completely eliminate the leakage to environment. Although a large amount of hydrogen is moved to the outer well 19 upon occurrence of a severe accident, the atmosphere in the outer well 19 is replaced by the nitrogen to limit oxygen concentration to a low level, thereby eliminating the risk of occurrence of the hydrogen detonation. As described above, according to the present embodiment, a large amount of particulate radioactive materials released from the core fuel upon occurrence of an accident can be confined inside the containment vessel by the double confinement function. The radioactive materials can be confined inside the containment vessel without an external power source but only with a passive means, so that even if a severe accident occurs resulting from a natural disaster such as a giant earthquake, it is possible to ensure safety of surrounding habitants without need of evacuation. A pressure rise in the containment vessel caused by a large amount of hydrogen generated from the core upon occurrence of a severe accident can be suppressed to a low level, so that even if the severe accident condition continues for a long time, it is possible to prevent occurrence of overpressure breakage of the containment vessel and excessive leakage. [Second Embodiment] FIG. 2 is an elevational cross-sectional view illustrating a containment vessel according to a second embodiment of the present invention. In the present embodiment, an upper end of the second cylindrical side wall 4b is located lower than that of the first cylindrical side wall 4a, and the second top slab 5b extends horizontally at a position lower than the first top slab 5a. In an example illustrated in FIG. 2, the second top slab 5b is joined to the first cylindrical side wall 4a. The joint part between the second top slab 5b and the first cylindrical side wall 4a may constitute a common part therebetween. In the present embodiment, when a fuel pool 27 (see FIG. 5) is arranged above the first and second top slabs 5a and 5b, a part of the fuel pool 27 that is located above the second top slab 5b can be made deeper than a part of the fuel pool 27 that is located above the first top slab 5a. [Third Embodiment] FIG. 3 is an elevational cross-sectional view illustrating a containment vessel according to a third embodiment of the present invention. In the present embodiment, a part of the outer well 19 is partitioned by a pressure-tight partition wall 22 to form an equipment room 23 with air atmosphere. In the equipment room 23, equipment such as residual heat removal system heat exchangers or panels for various electrical facilities can be installed. Other configurations are the same as those of the first embodiment. A volume of the outer well 19 is sufficiently large, so that a part of the outer well 19 can be used as the equipment room 23. In particular, the particulate radioactive materials do not leak outside the suppression pool 14 due to water sealing effect of the suppression pool water, so that it is effective to use this area as the equipment room 23. Further, in the present embodiment, the same effects as those in the first embodiment can be obtained. [Fourth Embodiment] FIG. 4 is an elevational cross-sectional view illustrating a containment vessel according to a fourth embodiment of the present invention. In the present embodiment, an outer pool 24 is provided at a lower portion of the outer well 19, a leading end of the gas-phase vent pipe 20 is guided to the water in the outer pool 24, and a scrubbing nozzle 25 is attached to the leading end portion of the gas-phase vent pipe 20. Other configurations are the same as those of the first embodiment. The scrubbing nozzle 25 is, e.g., a venturi nozzle. For example, as the venturi nozzle, one similar to a scrubbing nozzle of FILTRA MVSS developed against a severe accident in a Swedish BWR plant may be adopted. The outer pool 24 is separated from the suppression pool 14 by the first cylindrical side wall 4a so as to prevent the water from being circulated and mixed between them. According to the present embodiment, when the isolation and connection switching system 21 is opened upon occurrence of a reactor accident, high-pressure gas in the wet well 9 is guided to the water in the outer pool 24 through the gas-phase vent pipe 20. At this time, fine bubbles are generated in the water of the outer pool 24 by the scrubbing nozzle 25, and a minute amount of the particulate radioactive materials floating in the gas phase of the wet well 9 are dissolved in the water pooled in the outer pool 24. According to the fourth embodiment, it is possible not only to obtain the same effects as those in the first embodiment, but also to further suppress the particulate radioactive materials from leaking outside from the outer well 19. A medication such as sodium hydroxide that increases the dissolving property of iodine may be mixed in the water of the outer pool 24. This allows radioactive iodine to be dissolved in the water of the outer pool 24 more reliably. Alternatively, non-radioactive iodine may be mixed in the water of the outer pool 24. In this case, when the radioactive iodine flows into the water of the outer pool 24, replacement reaction between the radioactive organic iodine and non-radioactive iodine takes place, thereby efficiently eliminating the radioactive organic iodine. [Fifth Embodiment] FIG. 5 is an elevational cross-sectional view illustrating a nuclear power plant according to a fifth embodiment of the present invention. In the present embodiment, an upper protective barrier 26 against airplane crash is installed so as to cover an upper portion of the containment vessel with the second cylindrical side wall 4b and the second top slab 5b of the containment vessel 3 of the second embodiment (FIG. 2) as a base. In FIG. 5, illustration of the gas-phase vent pipe 20 is omitted. The upper protective barrier 26 does not constitute the containment vessel 3 and is thus need not have pressure tightness. Further, in the present embodiment, the fuel pool 27 is arranged above the first top slab 5a and the second top slab 5b, and the water shield 28 is arranged above the containment vessel head 6. The fuel pool 27 and the water shield 28 are located inside the upper protective barrier 26. According to the present embodiment, it is possible to protect a passive safety system (not illustrated) and the fuel pool 27 arranged above the top slabs 5a and 5b of the containment vessel 3 against airplane crash accident. A protective barrier against airplane crash that has conventionally been proposed is installed so as to rise from the base mat 7 and cover the entire outer periphery of the containment vessel 3 (e.g., double containment vessel). On the other hand, in the present embodiment, the protective barrier is installed on the second cylindrical side wall 4b, using the second cylindrical side wall 4b as a part of thereof, so that it is possible to significantly reduce cost and amount of material. The second cylindrical side wall 4b has a pressure-tight structure and thus serves as the protective barrier against airplane crash by itself, thereby eliminating the need to additionally provide a protective barrier for protecting the side wall portion. That is, according to the present embodiment, the containment vessel 3 itself is protected by the outer shell 18, thus eliminating the need to additionally provide a protective barrier for protecting the side wall portion. [Other Embodiments] The above embodiments are merely illustrative, and the present invention is not limited thereto. For example, the features of the respective embodiments can be combined together in very different ways. More specifically, although the upper protective barrier 26 and the like are added to the containment vessel of the second embodiment to achieve the fifth embodiment, the upper protective barrier 26 may be added to the containment vessels of the first, third, or fourth embodiments. Further, the gas-phase vent pipe 20 may be omitted in the first, second, third, and fifth embodiments. 1: Core 2: Reactor pressure vessel (RPV) 3: Containment vessel (CV) 4: Cylindrical side wall 4a: First cylindrical side wall 4b: Second cylindrical side wall 5: Top slab 5a: First top slab 5b: Second top slab 6: Containment vessel head 7: Basemat 8: Dry well (DW) 9: Wet well (suppression chamber, WW) 10: Vessel support 11: Vessel skirt 12: Upper DW 13: Lower DW 14: Suppression pool (SP) 15: Vent pipe 16: Diaphragm floor 17: Inner shell 18: Outer shell 19: Outer well 20: Gas-phase vent pipe 21: Isolation and connection switching system (ICSS) 22: Partition wall 23: Equipment room 24: Outer pool 25: Scrubbing nozzle 26: Upper protective barrier 27: Fuel pool 28: Water shield 30: Pedestal
044629559	description	DETAILED DESCRIPTION FIG. 1 shows a portion of a rack for a fuel element 1 fast at its lower part to a support structure 2 comprising part 3 for the engagement of the support structure 2 on the upper end of the support device according to the invention. The upper part of this support device is constituted by a support part 4 the upper portion of which, engaged in the part 3 of the support structure of the rack of fuel elements, is constructed in the shape of a vertical pin 6 including a shoulder 7 on which the structure 2 comes to rest with the interposition of support pads 8. Referring to FIGS. 1 and 2, it is seen that the lower portion of the part 4, of greater width than the upper portion, has a profiled portion 9 constituting a roller path. This roller path 9 is machined on the lower surface of the part 4. The support device comprises also a second intermediate support part 10 and a third support 11 itself resting on the bottom 12 of the pool of the fuel of the reactor. Between the support parts 4 and 10, are arranged two rollers with horizontal axes 14, 15, while between the support parts 10 and 11 are also arranged two rollers, with horizontal axes 17 and 18. The axes of the rollers 14 and 15 parallel with one another are oriented in a horizontal direction X, while the axes of the parallel rollers 17 and 18 are oriented in a second horizontal direction Y perpendicular to the direction X. The support part 10 has on its upper surface a roller track 20 and on its lower surface another roller track 21. The support part 11 comprises a roller track 24 on its upper surface. The rollers 14 and 15 are in contact through tracks 9 and 20 with the support parts 4 and 10, respectively. The rollers 17 and 18 are in contact with the parts 10 and 11 through tracks 21 and 24, respectively. The tracks 9 and 20 on the one hand, and 21 and 24 on the other hand, have a profiled shape in the transverse direction with respect to the rollers and have, in this direction, a succession of ramps (such as 9a, 9b and 9o on the roller path 9) having successively rising and descending profiles. The profiles of the ramp portions of two opposite, facing roller tracks (such as 9 and 20) are reversed. The rollers 14, 15, 17 and 18 comprise a cylindrical central portion and two terminal portions of short conical length enabling the centering of these rollers with respect to the roller tracks which are also profiled in the longitudinal direction with respect to the rollers to represent two inclined lateral parts such as 9e and 9f for the roller track 9. For example, the roller 15 comprises a cylindrical central portion 15a and two conical end parts 15b and 15c which come respectively into support on the inclined surfaces 9e and 9f of the roller track 9. The rollers have rotational axes (such as 25 for the roller 14) which enable the rollers 14 and 15 on the one hand and 17 and 18 on the other hand to be connected, through a linking element such as 27 traversed by the end of the axle 26 of the roller 15 on which is screwed a nut 28 (or the set 26', 27', 28' at the other end of the roller). The rollers 14 and 15 on the one hand and 17 and 18 on the other hand are thus connected to one another with a constant axial separation at each of their ends. Upon positioning of the support device on the bottom of the pool, the support parts and the rollers are kept in contact by means of screws 30 with a hexagonal head 31 enabling the supports 4 and 11 to be connected, and to exert a sufficient force between the supports and the rollers. When the support device has been placed in position, the linkages between the supports 4 and 11 are eliminated by removing the screws 30. The three support parts are then totally independent. When the borne element constituted by the fuel element rack is urged by a force in the direction X or in the direction Y, there occurs a movement of the element with respect to the support surface 12, either by movement of the set constituted by the borne element, the supports 4 and 10 as well as the set of upper rollers 14 and 15 with respect to the support part 11, by rolling of the roller 17 and 18 on the tracks 21 and 24, or by movement of the set constituted by the borne element and the support 4 with respect to the support 10, by rolling of the roller 14 and 15 on the tracks 9 and 20. If the borne element undergoes a stress in a different direction from X and from Y, the movement of this element with respect to the support surface 12 occurs at the same time through rolling of the rollers 14 and 15 and of the rollers 17 and 18. In all cases, the horizontal translation can only occur with a vertical movement of the upper part, hence of the borne element. The mass of the borne element is countered by gravity in the vertical movement, which permits, with a judicious choice of the shape of the profiles of the rollers paths, the selective combination of the acceleration and the displacement of the element with respect to the support. In all cases where the stresses originate in the fixed support, for example in the case of an earthquake causing large oscillations of the ground and of the support surface resting on the ground, the action of the support device to reduce the displacements and/or the accelerations of the borne element with respect to the support brings into play the same displacements as those which have been described in the case of a horizontal displacement of the borne element with respect to the fixed support. In all cases, the inertial forces in the vertical direction along an axis Z perpendicular to the axes Z and Y are transmitted integrally from the borne element to the bearer element, or conversely. In this case, neither the displacements nor the accelerations are therefore attenuated by the device according to the invention. In reality, in the case of an assembly rack for nuclear reactors, these racks are constituted by juxtaposed modular elements, and each of these modular elements is placed and supported on four devices of the type described. The reaction of the whole of the support device constituted by four elementary devices is similar to that of the elementary system itself. The invention is not limited to the embodiment which has just been described. Thus it is possible to conceive the use of any number of rollers in each of the upper or lower sets of the support device. These different rollers can be arranged with a fixed difference between centers by means of a junction bar connecting their axles, or they can be arranged freely individually or in partial groups, by provision of a special shape of the bearing tracks holding the rollers in spaced positions. The roller tracks can be attached to the support parts or machined directly in the the support parts. The rollers themselves can be produced in monoblock form or include several parts threaded onto the same axle. It is also possible to intercalate, between the lower support part resting on the fixed support and this fixed support, mechanical or hydraulic supporting and regulating means enabling the horizontality of the set of lower rollers to be regulated. Finally, the device according to the invention can find application outside of supports of racks for fuel assemblies in the storage pool of a pressurized water reactor. Thus it is possible to use these support devices each time that it is desired to avoid distortions of a supported structure which can undergo mechanical or thermal stresses. In all cases, the device enables the induced accelerations and the displacements to be minimized without the use of guidance locking or damping devices placed laterally with respect to the structure.
	summary
043307094	description	FIG. 1 is a sectional view of the electronic objective according to the invention. This objective is of revolution about its axis z z'. It comprises a core in two parts 1 and 2, one part surrounding the other. The inner part 2 is of ferrite and has a cylindrical portion 21 which is connected to two frustoconical portions 22 and 23 forming a divergent part in the vicinity of its output pupil 3. The outer part 1 of soft iron marries up with the shape of the part 2. It is separated therefrom by an airgap 4 and closes onto the output pupil. The output pupil is carried by support 5 of duralumin which is itself carried by the lower part of the polepiece. According to the invention, two magnetic deflectors 6 and 7 are provided, the deflector 6 being placed in the upstream part in the portion 21 of the lens and the other deflector 7 being placed in the region of the frustoconical portion 22. A diaphragm 8 located at the input of the objective limits the aperture of the electron beam. The two deflectors are each formed by an assembly of coils created a magnetic field perpendicular to the axis z z'. A coil 9 is wound around the parts 1 and 2. FIG. 2 represents, in a non-limitative example, the variation of the intensity B of the magnetic field created by the lens along the axis of the later, the origin z=0 being in the plane of the output pupil 3, the abscissae being in centimeters and the ordinates in Gauss. It can be seen that the two deflectors are placed so that the deflector 6 is upstream in the region where the field does not exceed 10 Gauss, and the other deflector 7 is downstream in a region where the field varies between 100 and 200 Gauss. The maximum value of the field after a relatively small increasing slope reaches its maximum value at 300 Gauss in the vicinity of z=-1 cm and drops to zero where Z=0. This being so, FIG. 3 is a top plan view of one of the deflectors, the other deflector being identical and FIG. 4 is a perspective view of the two deflectors. For reasons of clarity, only a part of each deflector has been shown in FIG. 4. Each deflector comprises (FIG. 3) two parts 61 and 62, 71 and 72, one of which is for scanning in x and the other for scanning in y. Each part is divided into two coils which are symmetrical relative to the axis z z' and disposed in series. Each of these coils is wound as shown in FIG. 4 around a portion of a cylinder of revolution subtending an angle of 120.degree. C. The two parts are disposed in such manner that their transverse axes of symmetry are perpendicular to each other. In one embodiment, the height of the cylinders is the same, namely 3 cm, the diameter of the inner cylinder is of the order of 2.4 cm and that of the outer cylinder is of the order of 5 cm. Each semi-deflector 61 or 62, 71 or 72 carries a variable current. The currents in the coils 61-71, 62-72 (not shown in FIG. 4) are respectively proportional to the amplitudes of deflection of the beam along the two axes Ox and Oy which are perpendicular to each other, the assembly forming with the axis z z' a reference trirectangular trihedral and the axes Ox and Oy being located in the plane of the object to be scanned. FIG. 4 shows that the two deflectors are offset by an angle .theta.=180.degree.+.alpha., .alpha. being between 35.degree. and 45.degree.. The ratio of the intensities in the two deflectors is constant and substantially equal to 2. Tests and calculation have shown that the objective according to the invention has the following advantages: (a) The spacing of the ferrite part 2 from the metal part 1 avoids eddy currents which retard the establishment of the magnetic field in the middle of each deflector in the case where a current pulse is applied to the two coils. On the other hand, the presence of the polepiece of soft iron prevents any saturation of the ferrite piece in the case where the lens is highly convergent. (b) The deflection by two successive deflecting stages and their respective angular offset minimizes aberrations, particularly in the case where the upper deflector is in the region where the axial field is weak, the second being in a region where the axial field is strong. The latter must be sufficiently remote from the output pupil and from the iron polepieces so that the transverse field it creates does not close onto the lower polepiece.
	claims	1. A method for manufacturing a control rod of a nuclear reactor, the control rod comprising a blade including neutron absorbers and sheathes, a tie rod to be fixed to the blade at a first groove, a handle to be fixed to the blade at a second groove and a lower-blade to be fixed to the blade at a third groove, said method comprising: cutting weep holes for water to cool the neutron absorbers in the sheath and cutting a periphery of the sheath; bending the sheath cut in the cutting step to a C-shape; inserting the neutron absorbers in a bent portion of the sheath formed by bending in the bending step; welding the blade to the tie rod so that the first groove is welded reliably to secure a penetration bead on a rear surface of the sheath by irradiating a laser beam on a first portion deviated from the first groove within a range of 2 mm, the blade to the handle so that the second groove is welded reliably to secure a penetration bead on the rear surface of the sheath by irradiating a laser beam on a second portion deviated from the second groove within a range of 2 mm, and the blade to the lower-blade so that the third groove is welded reliably to secure a penetration bead on the rear surface of the sheath by irradiating a laser beam on a third portion deviated from the third groove within a range of 2 mm; and finishing portions welded in the welding step. 2. A method for manufacturing a control rod of a nuclear reactor according to claim 1 , wherein the laser beam is one of a YAG laser beam or a CO2 laser beam. claim 1 3. A method for manufacturing a control rod of a nuclear reactor according to claim 1 , wherein the welding step comprises performing a TIG welding on a first position deviated from the first groove, a second position deviated from the second groove, and a third position deviated from the third groove within a range of 3 mm. claim 1 4. A method for manufacturing a control rod of a nuclear reactor according to one of the claims 1 , 2 or 3 , wherein the cutting step comprises cutting the weep holes and the sheath with high-pressure nitrogen gas. 5. A method for manufacturing a control rod of a nuclear reactor according to one of the claims 1 , 2 or 3 , wherein the inserting step comprises aligning ragged end faces of the sheath which are connected to the tie rod by laser cutting with high-pressure nitrogen gas. 6. A method for manufacturing a control rod of a nuclear reactor according to one of the claims 1 , 2 or 3 , wherein the welding step comprises forming two slits in one of the tie rod, the handle and the lower-blade, inserting projections of the blade in the slits, and irradiating the laser beam on one of a boundary between the blade and the tie rod and a boundary between the blade and the lower-blade. 7. A method for manufacturing a control rod of a nuclear reactor according to one of the claims 1 or 3 , wherein the welding step comprises welding the blade by irradiating one of a YAG laser beam or a CO 2 laser beam on a position deviated from the first, second, and third grooves toward a thick structure portion whose thickness is greater than a depth of the first, second, and third grooves respectively to form a penetration bead. 8. A method for manufacturing a control rod of a nuclear reactor according to claim 2 , wherein the welding step comprises welding the blade by irradiating said one of the YAG laser beam or the CO 2 laser beam on a position deviated from the first, second, and third grooves toward a thick structure portion whose thickness is greater than a depth of the first, second, and third grooves respectively to form a penetration bead. claim 2
051715201	abstract	A wear resistant coating (50) for fuel rod cladding (20) comprises a ceramic material (52) which is premixed with a glass (54). The cladding tube is heated and the ceramic/glass mixture is flame sprayed onto the cladding tube. The coating is applied to lower portions of the fuel rods (10) in the area of the first support grid (12) where debris tends to fret the fuel rod.
	claims	1. An apparatus for forming a nano pattern comprising:a laser to generate a beam;a beam splitter to split the beam from the laser into two beams having the same intensity;variable mirrors to reflect the two beams split by the beam splitter to a substrate;beam expansion units to expand the diameters of the two beams, respectively positioned on paths of the two beams traveling toward the substrate;a beam blocking unit, installed on an upper part of the substrate, to transmit only a specific region of the expanded beam through the beam expansion unit and to block a remaining region to form a uniform pattern; anda substrate transfer device to transfer the substrate vertically and horizontally, to allow the entire surface of the substrate to be irradiated, installed on a lower part of the substrate,wherein the beam blocking unit only transmits a central part of the expanded beams, the central part of the beams having maximum intensity,wherein the substrate transfer device transfers substrate sequentially by an equal amount to each section of the uniform pattern, andthe central parts of the beams are limited to being greater than half of the maximum intensity thereof. 2. The apparatus for forming the nano pattern according to claim 1, further comprising reflection mirrors to change a path of the beam generated by the laser disposed between the laser and the beam splitter. 3. A method for forming a nano pattern comprising:generating a beam through a laser;splitting the beam into two beams having the same intensity through a beam splitter;directing the two beams to a substrate through variable mirrors;expanding diameters of the beams through beam expansion units respectively positioned on paths of the two beams traveling toward the substrate;illuminating the substrate by transmitting only a central part of the expanded beams through a beam blocking unit installed on an upper part of the substrate;irradiating the beams over the entire surface of the substrate to form a uniform pattern by a movement of a substrate transfer device having the substrate mounted thereon and installed on a lower part of the substrate, the substrate transfer device being moved vertically and horizontally by amounts equal to each section of the uniform pattern, the central part of the beams having a maximum intensity; andirradiating the beams sequentially forming the uniform patterns on the substrate by transferring the substrate as much as each uniform pattern,wherein the central parts of the beams are limited to being greater than half of the maximum intensity thereof. 4. The method according to claim 3, further comprising coating the substrate with UV curable resin. 5. The method according to claim 3, further comprising:changing a path of the beam generated from the laser through at least one reflection mirror.
043308643	abstract	Methods and apparatus for plasma generation, confinement and control such as Tokamak plasma systems are described having a two layer field shaping coil system comprising an inner coil layer close to the plasma and an outer coil layer to minimize the current in the inner coil layer.
050892134	abstract	A nuclear fuel identification code reader has an optical sensor for detecting a first nuclear fuel identification code marked on a fuel assembly and an ultrasonic wave sensor for detecting a second nuclear fuel identification code marked on the fuel assembly. It further has first means for recognizing the nuclear fuel identification code based on information derived from the optical sensor and second means for recognizing the nuclear fuel identification code based on information derived from the ultrasonic wave sensor. When the nuclear fuel identification code cannot be recognized by the first means, the detection by the ultrasonic wave sensor and the recognition of the nuclear fuel identification code by the second means are effected. The nuclear fuel identification code can be recognized in a short time with a high accuracy.
	claims	1. An operation method of a boiling water type nuclear reactor core in which a plurality of fuel assemblies, each enclosed in a channel box, are loaded and a plurality of control rods, each having control blades, are arranged between said channel boxes, characterized in that: long blade control rods, each having control rod blades which extend in four directions and each of which is arranged between channel boxes on a diagonal line of square bundle regions, each square bundle region being formed by a plurality of fuel assemblies; short blade control rods, each having a latitudinal control rod blade length of about one half of the width of each of said square bundle regions and each of which is arranged between said channel boxes in the center of each of said square bundle regions; said long blade control rods each having a latitudinal control rod blade length of about one of said square bundle regions so as to be twice as long as the latitudinal control rod blade length of each of said short blade control rods; and wherein reactivity control during operation and at time of scram is effected by using said short blade control rods arranged between said central channel boxes of said square bundle region. 2. An operation method of a boiling water type nuclear reactor core in which a plurality of fuel assemblies, each enclosed in a channel box, are loaded and a plurality of control rods, each having control blades, are arranged between said channel boxes, characterized in that: long blade control rods, each having control rod blades which extend in four directions and each of which is arranged between channel boxes on a diagonal line of square bundle regions, each square bundle region being formed by a plurality of fuel assemblies; short blade control rods, each having a latitudinal control rod blade length of about one half of the width of each of said square bundle regions and each of which is arranged between said channel boxes in the center of each of said square bundle regions; said long blade control rods each having a latitudinal control rod blade length of about of said square bundle regions so as to be twice as long as the latitudinal control rod blade length of each of said short blade control rods; and wherein reactivity control at time of the reactor being shutdown is effected by using said long blade control rods arranged between said channel boxes on the diagonal lines of said square bundle regions. 3. An operation method of a boiling water nuclear reactor core in which a plurality of fuel assemblies, each enclosed in a channel box, are loaded and a plurality of control rods, each having control blades, are arranged between said channel boxes, characterized in that: long blade control rods, each having control rod blades which extend in four directions and each of which is arranged between channel boxes on a diagonal line of square bundle regions, each square bundle region being formed by a plurality of fuel assemblies; short blade control rods, each having a latitudinal control rod blade length of about one half of the width of each of said square bundle regions and each of which is arranged between said channel boxes in the center of each of said square bundle regions; said long blade control rods each having a latitudinal control rod blade length of about one of said square bundle regions so as to be twice as long as the latitudinal control rod blade length of each of said short blade control rods; and wherein reactivity control in normal operation is effected by using said long blade control rods arranged between said channel boxes on the diagonal of said square bundle regions.
046997610	claims	1. In a reconstitutable fuel assembly having at least one control rod guide thimble and a top nozzle, said guide thimble including an upper end portion having an annular externally threaded section, said top nozzle including at least one tubular alignment sleeve having a lower annular internally threaded section and being rototably movable relative to said guide thimble upper end portion between lowered and raised positions for threading and unthreading its internally threaded section onto and from said externally threaded section of said guide thimble upper end portion for attaching and detaching said top nozzle onto and from said guide thimble, and intergral reusable locking arrangement for said top nozzle comprising: (a) inner means mounted on said guide thimble upper end portion above said externally threaded section thereon; and (b) outer means mounted on said alignment sleeve above said internally threaded section thereon; (c) said inner and outer means being configured to coact with one another as said internally threaded section of said alignment sleeve is threaded on said externally threaded section of said guide thimble upper end portion when attaching said top nozzle to said guide thimble and to provide a locking force which must be overcome in order to unthread said internally threaded section of said alignment sleeve from said externally threaded section of said guide thimble upper end portion for detaching said top nozzle from said guide thimble. said inner means takes the form of a thin-walled tubular section on said guide thimble upper end portion having a first external diametric size; said outer means takes the form of an axial section on said alignment sleeve having a second internal diametric size which is greater than said first external diametric size of said thin-walled tubular section for accommodating insertion of said tubular section into said axial section; and a protruding region is defined on one of said tubular and axial sections and has a third diametric size being proportioned relative to said first and second diametric sizes of said respective tubular and axial sections whereby rotational movement of said alignment sleeve relative to said guide thimble upper end portion from said raised toward said lowered position causes interference contact of said protruding region with the other of said tubular and axial sections so as to produce said locking force as said internally threaded section of said alignment sleeve is threaded onto said externally threaded section of said guide thimble upper end portion. 2. The locking arrangement as recited in claim 1, wherein said locking force takes the form of a constant torsional drag produced between said inner and outer means as said alignment sleeve is rotatably moved relative to said guide thimble upper end portion between said lowered and raised positions. 3. The locking arrangement as recited in claim 1, where said outer means on said alignment sleeve and said inner means on said guide thimble upper end portion are axially displaced from one another when said internally threaded section on said alignment sleeve is initially rotatably moved into threaded engagement with said externally threaded section on said guide thimble upper end portion whereby the mechanical advantage produced by threading said internally threaded section of said alignment sleeve onto said externally threaded section of said guide thimble upper end portion can be used to overcome said locking force as said alignment sleeve is threaded onto said guide thimble upper end portion. 4. The locking arrangement as recited in claim 1, wherein said inner means takes the form of a thin-walled tubular section on said guide thimble upper end portion having a first external diametric size and an enlarged region defined thereon of a second external diametric size which is greater than said first external diametric size of the remainder of said tubular section. 5. The locking arrangement as recited in claim 4, wherein said outer means takes the form of an axial section on said alignment sleeve having a third internal diametric size which is greater than said first external diametric size of said thin-walled tubular section on said guide thimble upper end portion but less than said second external diametric size of said enlarged region on said tubular section, whereby rotational movement of said alignment sleeve relative to said guide thimble upper end portion from said raised toward said lowered position causes interference contact of said axial section of said alignment sleeve with said tubular section enlarged region of said guide thimble upper end portion so as to produce said locking force. 6. The locking arrangement as recited in claim 5, wherein said enlarged region takes the form of a circumferential protrusion on said tubular section. 7. The locking arrangement as recited in claim 1, wherein: 8. The locking arrangement as recited in claim 7, wherein said locking force takes the form of a constant torsional drag produced between said protruding region and said other of said tubular and axial sections as said alignment sleeve is rotatably moved relative to said guide thimble upper end portion between said lowered and raised positions. 9. The locking arrangement as recited in claim 7, wherein said protruding region on said one of said tubular and axial sections is axially displaced from said other of said tubular and axial sections when said internally threaded section on said alignment sleeve is initially rotatably moved into threaded engagement with said externally threaded section on said guide thimble upper end portion whereby the mechanical advantage produced by threading said internally threaded section of said alignment sleeve onto said externally threaded section of said guide thimble upper end portion can be used to overcome said locking force as said alignment sleeve is threaded onto said guide thimble upper end portion. 10. The locking arrangement as recited in claim 7, wherein said first diametric size of said tubular section is less than the exterior diametric size of said externally threaded section of said guide thimble upper end portion. 11. The locking arrangement as recited in claim 7, wherein said second diametric size of said axial section is less than the interior diametric size of said internally threaded section of said alignment sleeve. 12. The locking arrangement as recited in claim 7, wherein said enlarged region takes the form of a circumferential protrusion on said tubular section.
	description	This application is a Divisional of U.S. application Ser. No. 12/162,067, filed Jul. 24, 2008, which is a national stage application filed under 35 USC §371 of International Application No. PCT/JP2007/051047, filed Jan. 24, 2007, which claims the benefit of priority from Japanese Application No. 2006-16519, filed on Jan. 25, 2005, Japanese Application No. 2006-58847, filed on Mar. 6, 2006 and Japanese Application No. 2006-58862, filed on Mar. 6, 2006, the entire disclosures of which are hereby incorporated by reference. The present invention relates to an inspection apparatus and an inspection method for inspecting a pattern formed in a surface of a sample and in particular, to a projection type electron beam sample inspection apparatus for inspecting or evaluating a pattern (for example, an overlay mark pattern) formed in a sample, such as a wafer or a substrate, by irradiating an electron beam onto the surface of the sample and an inspection method for inspecting or evaluating the pattern by using the same inspection apparatus. A semiconductor manufacturing process involves the steps of exposing, etching and thin-film deposition, which steps are repeated several or a dozen times. One critical factor in those steps is defects that could be created in respective steps, and so the detection of electrical defects can be critical among others. In addition, matching (overlay) of locations between a wiring pattern formed in an under layer and a wiring pattern to be formed in an upper layer in a plurality of wiring patterns stacked one on top of the other is also critical. It is extremely difficult for a conventional optical microscope to detect the electrical defect and it takes a long inspection period for a SEM (Scanning type Electron Microscope) to make an inspection over a large area. Further, in such an inspection apparatus using an electron beam, an effect from charge-up in a sample surface could inhibit a clear image from being obtained. Further, in a conventional approach, the matching has been provided, for example, by making an alignment (an overlay inspection) by means of a light (an optical microscope) in conjunction with a mark of specified purpose (an overlay mark) employed for alignment of the locations between the pattern in the under layer and the pattern in the upper layer. Patent document: U.S. Pat. No. 6,091,249 As described above, in the inspection of the sample surface by using the electron beam, a resultant image could lack focus due to the charge-up in the sample surface caused by the electron beam irradiation. In addition, since the overly mark has a different pattern size from that of the actual device pattern, such an overlay inspection using light is subject to an effect of coma aberration from the light, often resulting in an alignment offset in which the actual device pattern is shifted and exposed to the light, even if the overlay mark is within a tolerance range in the alignment. Further, since the overly mark has a different pattern size from that of the actual device pattern, such overlay inspection by means of the light as described above is subject to an effect of coma aberration from the light, often resulting in the alignment offset in which the actual device pattern is shifted and exposed to the light, even if the overlay mark is within a tolerance range in the alignment. The present invention has been made in the light of the problems pointed above, and an object thereof is to provide an inspection method and an inspection apparatus for inspecting a sample surface with highly improved accuracy enabled by controlling a sample voltage with charge-up in the sample taken into account, which would not be provided by the prior art, in the sample surface inspection apparatus used in a manufacturing process of a semiconductor device. Another object of the present invention is to provide an inspection method and an inspection apparatus which enable a surface inspection to be carried with high accuracy by modifying a sample voltage in dependence on an amount of the electron beam. Still another object of the present invention is to provide an inspection apparatus and an inspection method for inspecting a sample with high efficiency and high accuracy enabled by controlling a stage such that the stage may be moved in synchronism with an operating frequency of a sensor during inspection and a time required to move the stage may be minimized during the stage being moved between patterns to be inspected. Another object of the present invention is to provide a projection type inspection apparatus or an inspection method for inspecting a surface adapted to improve a speed and accuracy in an inspection of a pattern by controlling an irradiation geometry of an electron beam relative to a pattern so as to be associated with a movement of a sample or by elongating it along the moving direction of the sample. According to the present invention as defined in claim 1, provided is a method for inspecting a sample surface by using an electron beam method sample surface inspection apparatus, in which an electron beam generated by an electron gun of the electron beam method sample surface inspection apparatus is irradiated onto the sample surface, and secondary electrons emanating from the sample surface are formed into an image toward an electron detection plane of a detector for inspecting the sample surface, the method characterized in that a condition for forming the secondary electrons into an image on the detection plane of the detector is controlled such that a potential in the sample surface varies in dependence on an amount of the electron beam irradiated onto the sample surface. In one method for controlling the image forming condition for the secondary electrons in the present invention, a sample voltage or a retarding voltage may be modified in dependence on an amount of the electron beam irradiated onto the sample surface. Further, the detector may be an EB-CCD. It is to be noted that the detector may comprise a MCP and a TDI-CCD. According to the present invention as defined in claim 4, provided is an electron beam method sample surface inspection apparatus, comprising: an electron gun for generating an electron beam to be irradiated onto a sample surface; a primary optical system for guiding the electron beam onto the sample surface; a detector for detecting secondary electrons emanating from the sample surface; and a secondary optical system for guiding the secondary electrons onto the detector, the apparatus characterized in further comprising a voltage adjustment mechanism for modifying a potential in the sample surface in dependence on an amount of the electron beam. In the invention as designated above, the apparatus may comprise as the voltage adjustment mechanism a means for modifying the sample voltage or the retarding voltage in dependence on an amount of the electron beam irradiated onto the sample surface. Further, the detector may be an EB-CCD. It is to be noted that the detector may comprise a MCP and a TDI-CCD. In the method and apparatus for inspecting a surface of a sample to provide a defect inspection or the like for a semiconductor device according to the present invention as designated above, preferably, the secondary optical system for guiding secondary electrons emanating from the sample surface in response to the electron beam irradiated onto the semiconductor wafer to the detector may include a quadrupole lens and further the method may include a step for forming the secondary electrons into an image by using a plurality of electrostatic lenses. Further, the detector for the secondary electrons may include, in addition to the MCP and the TDI-CCD as designated above, a fluorescent screen between the MCP and the TDI-CCD. Alternatively, an EB-TDI may be used instead of the MCP and the TDI-CCD, or an EB-CCD may also be used. In the present invention as designated above, the voltage adjustment mechanism or the means for modifying the retarding voltage may comprise a stabilizing direct current power source for modifying an output voltage in accordance with an external signal and a computer serving for controlling the voltage modification, in which a command is input to the computer so that a resultant output value (output voltage) of the stabilizing current power source represents a desired value for modifying the potential in the sample surface. According to the invention as defined in claim 7, provided is an inspection method for inspecting a pattern formed in a sample by using an electron beam, the method characterized in that a stage holding a sample thereon is moved at a frequency in synchronism with an operating frequency of a sensor during inspection of a pattern to be inspected and a moving speed of the stage is controlled so that a time required for movement is minimized during the stage being moved to another pattern to be inspected. In the inspection method as designated above, the pattern to be inspected may include two or more patterns consisting of different sectional structures or different materials, and a plurality of patterns may be inspected concurrently. According to the invention as defined in claim 9, provided is an inspection apparatus for inspecting a pattern formed in a sample by using an electron beam, comprising: a holding mechanism for holding the sample; a stage with the holding mechanism mounted thereon, and adapted to be movable in at least one direction; an electron beam source for generating electrons for irradiation of the electron beam directed to the sample; a first electro-optical system for guiding the electron beam generated from the electron beam source onto the sample for irradiation of the electron beam to the sample; a detector for detecting electrons emanating from the sample; and a second electro-optical system for guiding the electrons to the detector, the apparatus further comprising a control unit to provide control so that the stage is moved at a speed in synchronism with an operating speed of the detector during inspection of the pattern, and the stage is accelerated when being moved to another pattern on the sample. In the inspection apparatus as designated above, the pattern to be inspected may include two or more patterns consisting of different sectional structures or different materials, and a plurality of patterns may be inspected concurrently. According to another aspect of the invention, provided is an inspection apparatus for inspecting a pattern formed on a sample by using an electron beam, comprising: a holding mechanism for holding the sample; a stage with the holding mechanism mounted thereon, and adapted to be movable in at least one direction; an electron beam source for generating electrons for irradiation of the electron beam directed to the sample; a first electro-optical system for guiding the electron beam generated from the electron beam source onto the sample for irradiation of the electron beam to the sample; a detector for detecting electrons emanating from the sample; and a second electro-optical system for guiding the electrons to the detector, wherein an irradiation geometry of the electron beam to the pattern defines an elongated irradiation geometry that is longer than a length of the pattern along the moving direction of the stage during the stage being moved serially for inspecting the pattern so that the pattern could have been previously subject to the irradiation of electrons. Further, according to another aspect of the invention, provided is an inspection apparatus for inspecting a pattern formed on a sample by using an electron beam, comprising: a holding mechanism for holding the sample; a stage with the holding mechanism mounted thereon, and adapted to be movable in at least one direction; an electron beam source for generating electrons for irradiation of the electron beam directed to the sample; a first electro-optical system for guiding the electron beam generated from the electron beam source onto the sample for irradiation of the electron beam to the sample; a detector for detecting electrons emanating from the sample; and a second electro-optical system for guiding the electrons to the detector, the inspection apparatus further comprising a control unit for controlling an irradiation geometry of the electron beam in association with an operation of the stage so that the irradiation geometry of the electron beam onto the pattern allows the pattern to be previously subject to the irradiation of electrons during the stage of moving serially for inspecting the pattern. In the sample surface inspection apparatus according to the present invention as designated above, the secondary optical system for guiding secondary electrons emanating from the sample surface in response to the electron beam irradiated onto the sample, such as a semiconductor wafer, to the detector may include a quadrupole lens and the apparatus may further include a step for forming the secondary electrons into an image by using a plurality of electrostatic lenses. Further, the detector for the secondary electrons emanating from the sample may comprise the TDI and the fluorescent screen. Further, the detector for the secondary electrons may include, in addition to the fluorescent screen and the TDI-CCD as designated above, a MCP located before the fluorescent screen. Alternatively, an EB-TDI may be used instead of the MCP and the TDI-CCD, or an EB-CCD may also be used. Further, a combination of the MCP and the EB-CCD may be employed. In the inspection apparatus as designated above, the pattern to be inspected may include two or more patterns consisting of different sectional structures or different materials, and a plurality of patterns may be inspected concurrently. As stated above, according to the present invention, in the inspection of the surface of the sample, such as a wafer, a substrate and the like, in the manufacturing process of the semiconductor device, the surface inspection with high accuracy can be achieved by modifying the sample voltage in dependence on an amount of the electron beam and thus quality and throughput of the semiconductor device can be improved. Further, in the sample surface inspection, the detection of the overlay can be accomplished and thus the sample surface inspection apparatus with high accuracy in the semiconductor device manufacturing process can be supplied. In addition, in the manufacturing of the semiconductor device, the detection of the overlay can be accomplished quickly yet with high accuracy and thus the defect inspection apparatus with high accuracy in the semiconductor device manufacturing can be supplied. 1, 1a Sample inspection apparatus 2, 2a Primary optical system 3 Secondary optical system 4 Detection system 5, 5a Stage unit 12 Chamber 21, 21a Electron gun 23 ExB filter 41, 41a Detector 42 Storage unit An embodiment of a method for inspecting a sample surface for any defects or the like according to the present invention will be described below. First, referring to FIG. 1, an entire apparatus for implementing the embodiment of a surface inspection method for inspecting a sample surface for any defect is shown with reference numeral 1. In FIG. 1, reference numeral 2 designates a primary electro-optical system (hereinafter, simply referred to as a primary optical system), 3 a secondary electro-optical system (hereinafter, simply referred to as a secondary optical system), 4 a detection system, 5 stage unit disposed on a vibration isolation bed having a known structure, all of which are contained in a housing 11 defining a chamber 12. The chamber 12 is constructed such that it can be controlled to have a desired atmosphere, a vacuum atmosphere, for example, by a unit which is not shown. A sample “W”, such as a wafer or a substrate, for example (the following description of the present embodiment is directed to an example using the wafer as the sample) can be securely but removably placed on a wafer holding table 51 in the stage unit 5 having a known structure and function by a known means, such as an electrostatic chuck, for example. The wafer holding table 51 is configured to move serially or in a step-and-repeat manner in at least one direction of two orthogonal axial directions, or X and Y directions. A vibration proofing structure of the vibration isolating bed may be formed from a non-contacting bearing. As shown in detail in FIG. 2, an electron gun 21 of the primary optical system for irradiating a primary electron beam may use an electron gun of a thermionic emission type or a Schottky type. The primary electron beam “B1” emitted from the electron gun 21 will have its configuration shaped properly via a quadrupole lens 22 and the like of the primary optical system and then irradiated onto the surface of the sample or the wafer W placed on the wafer holding table 51. In this stage, the primary electron beam is guided through an ExB filter or Wien filter 23 comprising an electric field and a magnetic field to the wafer surface. The geometry of the primary electron beam emitted from the electron gun 21 of the primary optical system 2 may be shaped such that it is irradiated onto the sample surface with uniform distribution to an extent larger than an area corresponding to pixels of a TDI-CCD or a CCD constructing a detector 41 of the detection system 4. Secondary electrons “B2” are generated from the surface of the wafer W in response to the irradiation of the primary electron beam, by an amount corresponding to energy of the primary electron beam. Those secondary electrons are accelerated by an electrode located adjacent to the wafer toward the defector side until the secondary electrons have a predetermined amount of kinetic energy. The accelerated secondary electrons B2 go straight through the ExB filter or Wien filter 23 comprising the electric field and the magnetic field as described above, and are guided to the secondary electro-optical system (hereinafter simply referred to as the secondary optical system) 3. In this stage, the wafer surface could have been charged by the irradiation of the primary electron beam, and consequently the secondary electrons may occasionally fail in acceleration to the predetermined amount of kinetic energy. In the event of such a failure, the secondary electrons could not be successfully formed into an image on a detection plane of the detector 41, resulting in no image obtained or an unfocused image. To address this, a charge amount from the electron beam irradiation over the wafer surface should be previously calculated, and the sample voltage or the retarding voltage should be modified adaptively in dependence on the calculated charge amount. This enables the secondary electrons to be accelerated to the predetermined amount of kinetic energy by taking the amount of charging from the electron beam irradiation into account. Secondary electrons are formed into an image on the detector 41 as a map projection image by the secondary optical system 3. The electric lens or electrostatic lens 31, a component of the secondary optical system 3, comprises plural sheets of coaxially located electrodes having apertures or a plurality of electrode groups disposed coaxially, wherein a number of thus configured lenses are disposed in multi-level. The electric lens serves to enlarge image data possessed by the secondary electrons, while guiding it to the detector as map projection data so as not to lose position and surface data on the wafer W. The detector 41 may comprise a MCP (Multi Channel Plate) in conjunction with a fluorescent screen and a TD-CCD or EB-CCD or EB-TDI. The electrons multiplied by the MCP are then converted to light in the fluorescent screen, which light signal is taken by the TDI-CCD and output as an image signal. Alternatively, the secondary electrons may be directly introduced into the EB-CCD for converting into the image signal. It is to be noted that each of the components of the primary and the secondary optical system as well as the detecting system may have a known structure and function, and so any further description should be herein omitted. The stage unit 5 for holding the wafer W may have a structure to provide a serial movement, if the detector is the TDI-CCD or the EB-TDI. Further, the stage is structured not only to make a serial movement but also to repeat a go-and-stop motion in case of the detector implemented by the TDI-CCD or the EB-TDI. If the detector is the CCD or the EB-CCD, the stage is also allowed to repeat the go-and-stop motion. The position of the stage is always measured by a laser interferometer, though not shown, in a known method, and a current value of the position given by the measurement from the laser interferometer is compared to a predetermined target value, and based on a resultant residual error, a signal for correcting the residual error is sent to an electrostatic lens control unit (not shown) of the secondary optical system 3. A correction mechanism is provided, in which a moving and stopping motion or a speed fleck and minute vibration during these motions may be corrected by modifying the path of the secondary electrons by means of the electrostatic lens as described above, so that a stable image-forming condition can be always provided on the detection plane of the detector. The stage unit is provided with a brake system (not shown), and the brake system may be used upon stopping of the stage so as to reduce or even eliminate any minute vibration during stopping motion. If the detector is the TDI or the EB-TDI, the apparatus has such a function that the moving distance of the stage is measured by the laser interferometer, and the image data taken by the TDI or the EB-TDI may be forwarded each time the stage is moved by a predetermined distance. Electric image data obtained by the detector 41 is stored in a storage unit 42. The storage unit 42 is contained in a control section for controlling the TDI-CCD so as to synchronize the timing for controlling the TDI-CCD with the timing for storing data. The image signal is input by a known method to an image processing unit though not shown, where signal processing or image analysis is carried out in a known method to identify the location of defect and determine the type of defect, and the result may be notified to an observer, while at the same time being stored in a storage media. For the overlay inspection, a shift length in an orthogonal two directions or in the X and Y directions and a shift amount in a rotational angle (θ) between the under layer pattern formed in advance and the upper layer pattern formed thereon are calculated from the image analysis to determine whether the overlay is right or wrong. For the defect inspection, a cell-to-cell inspection for making a comparison between patterns in a repeated pattern arrangement or a die-to-die inspection for making a comparison between images through pattern matching by every die may be applied. Alternatively, a die-to-any die inspection for making a comparison of one die to other many dies or a die-to-CAD data inspection for making a comparison of one die to a predetermined pattern in the specific design may be applied. To determine whether a defect exists or not, a difference is determined relative to the comparative image and a site with a larger difference should be considered defective. Further, for the defect inspection, a physical defect in an oxide film transcription pattern or in a wiring, an electrical defect of short-circuit and an electrical defect of open-circuit, such as potential contrast or voltage contrast, can be also detected. The items to be inspected may be a product of wafer, a TEG (Test Element Group), a reticle or a mask. The inspection may be selectively performed in an on-line or off-line inspection, and it is also possible in the on-line inspection method to provide a feedback of an inspection result directly to a semiconductor manufacturing line as an electric signal or the like via a signal line. Further, it is also possible in the off-line inspection method that the inspection result is directly input from a terminal of the inspection apparatus to provide a feedback thereof to the semiconductor manufacturing line as an electric signal or the like via a signal line. The inspection result may be used for quality control in the course of manufacturing process via a communication with a host computer in the semiconductor manufacturing line. With reference to FIG. 1, the description is now directed to an operation for loading the wafer W as before the inspection onto the stage unit 5 within the chamber 12 and unloading the wafer W as after the inspection from the stage unit. A preparatory environment compartment 62 located adjacent to the chamber 12 of the sample surface inspection apparatus 1 is configured such that in the semiconductor manufacturing process, an environment associated with the wafer carried in from the outside is altered to an environment existing inside the chamber 12 where the stage unit 5 with the wafer holding table 51 is located, until the environment within the preparatory environment compartment 62 is in conformity with the environment inside the chamber 12 to allow the wafer as before the inspection to be carried in from the preparatory environment compartment 62 onto the wafer holding table. Specifically, a gate valve 63 is disposed between the housing 11 and a housing 61. The housing 11 defines the chamber 12 containing the vibration isolating bed having a known vibration proofing structure, and the stage unit 5 having the wafer holding table 51. The stage unit 5 is disposed on the vibration isolating bed. The housing 61 defines the preparatory environment compartment 62. The chamber 12 and the preparatory environment compartment 62 can be selectively placed in communication with each other or blocked from each other, via the gate valve 53. In addition, another gate valve or flange may be arranged in order to introduce, into the preparatory environment compartment, the wafer in the chamber and the preparatory environment compartment 62. In this regard, when the wafer is transferred between the preparatory environment compartment 62 and the chamber 12 through the gate valve 63, the environments inside both of the chamber and the compartment are kept substantially equal (e.g., in a vacuum atmosphere at a degree of vacuum around 10−4 Pa to 10−6 Pa). Since in the semiconductor manufacturing process, the wafer subject to the inspection before being transferred to a subsequent step is held in an environment suitable for a transfer to the subsequent step, the preparatory environment compartment is firstly controlled to achieve the environment for transferring the wafer to the subsequent step in a known manner by means of a gas supply unit (not shown) and a vacuum evacuation unit, both having a known structure. Once the environment for transferring the wafer to the subsequent step and the environment inside the preparatory environment compartment (vacuum condition) have become equal, the another valve or flange operable to introduce the wafer into the preparatory environment compartment is opened to allow the wafer to be introduced into the preparatory environment compartment 62, where the vacuum evacuation system or the gas supply unit as mentioned above is controlled to now achieve the same environment (vacuum condition) as the environment in which the wafer holding table 51 is located or inside the chamber 12. After that, the gate valve 63 for isolating the chamber 12 from the preparatory environment compartment 62 is opened to allow the wafer W as before the inspection to be transferred onto the wafer holding table 51 (this step referred to as loading). After the transfer of the wafer as before the inspection having been completed, the gate valve 63 is closed, and the environment in which the wafer holding table is located is adjusted to be suitable for the inspection and then the inspection is started. When the wafer having finished with the inspection is carried out of the wafer holding table 51 (the operation referred to as unloading) and transferred to the subsequent step, the operation may be carried out in an inverse order to the loading. In this regard, preferably the vacuum evacuation unit may be implemented by a combination of a turbo-molecular pump 66 with a dry-root pump 67, but a rotary pump equipped with an oil mist trap or a molecular sieve may be used instead of the dry-roots pump. FIG. 3 shows an embodiment comprising a plurality (two in the illustrated embodiment) of preparatory environment compartments 62. The loading and the unloading operations of the wafer to be inspected may be carried out concurrently in a parallel manner. In addition, the preparatory environment compartment may have a function for storing a stock consisting of a plurality of wafers at one time. In this case, the number of operations for opening the gate valve may be reduced and so an efficient inspection as well as loading and unloading operations can be achieved. FIG. 4 shows a control flow of a wafer voltage (also referred to as a substrate voltage, a sample voltage or a retarding voltage, whereas collectively referred to as the wafer voltage for the purport of clarity). The flow as illustrated in FIG. 4 represents the flow in one-shoot image-taking in the Still-mode with the CCD or the EB-CCD or the TDI-CCD. The wafer voltage (the substrate voltage, the sample voltage or the retarding voltage) is referred to as a voltage that is previously applied to a sample, such as a wafer and a substrate. This represents the embodiment in which a Dose amount (referred to as a dosage of the electron beam, representing an amount of irradiated charges as per a unit area over a sample such as a wafer and a substrate, hereinafter referred to as the Dose amount) is calculated from a signal of current density and a blanking signal so as to control the EB-CCD by using the blanking signal. A current density “Je” can be computed from an electron current value of an electron gun. The Dose amount for the wafer surface can be calculated from the current density Je and a blanking cancellation time “τS” of the blanking signal. Wherein, Dose amount=Je·τS The electrostatic capacity “C” as per unit area in the sample surface, or the wafer surface, can be determined from the data on the wafer surface, for example, a resist thickness “d” and a relative dielectric constant “∈r”. Wherein, C=∈r·∈0/d (unit area is calculated by cm2, ∈0 is a dielectric constant in vacuum) In addition, from CV=Q, a variation in wafer surface voltage ΔV=Q/C, wherein, the wafer surface voltage may be also referred to as a substrate surface voltage or a sample surface voltage, representing a voltage determined by summing up (superposing) an originally applied wafer voltage and a voltage applied through the irradiation of the electron beam to the wafer. On the other hand, the “Q” represents a total amount of electrons irradiated to the wafer surface and assuming that a secondary electron emission rate is denoted by “γ” at the time of landing energy “LE” (keV), thenQ=Dose amount·(1−γ)=Je·τS·(1−γ) Therefore, the variation in wafer surface voltage can be expressed as follows:ΔV=Je·τS·(1−γ)·d/∈r·∈0 Accordingly, the wafer voltage (or the retarding voltage) RTD should be adjusted to satisfyRTD+ΔV=design value (secondary electron drawing voltage). FIG. 5 shows another control flow of the wafer voltage. This represents an embodiment for a case where the blanking signal is determined based on the signal from EB-CCD, and the Dose amount is determined from the blanking signal and a current density signal. FIG. 6 illustrates a relationship among the wafer voltage, the EB-CCD and the blanking signal, when one-shoot image-taking in the Still-mode with the CCD or EB-CCD or TDI-CCD is performed serially by a number of times. Since the Dose amount varies at each image-taking operation, therefore the wafer voltage (the retarding voltage) must be adjusted in each case. That is to say, the same image can be always obtained by adjusting the wafer voltage in each case, and integration is applied to those images to obtain an image with high S/N ratio and thus to improve the precision during image analysis. It is to be noted that the integration may be repeated by any times as desired. Specifically, an optimal number of times of integration may be set according to the specific conditions of the wafer. In this way, the inspection can be carried out under an optimal inspection condition according to the specific wafer. FIG. 7 shows another embodiment of the blanking signal. In this embodiment, since a blanking cancellation would occur by a number of times during an exposure period to the EB-CCD, the variation in wafer surface voltage ΔV can be expressed as follows:ΔV=Je·Σ(τS)·(1−γ)·d/∈r·∈0 In this way, the image can be obtained by adjusting the Dose mount such that the sum of the wafer voltage and the variation in wafer surface voltage can satisfy the image formation condition for the secondary optical system. The exposure period and the blanking cancellation period can be determined relatively as desired. Specifically, the blanking cancellation period may be longer than the exposure period. In this case, to calculate the Dose amount, the exposure time may be substituted for the τS. Referring now to FIG. 8, a specific image forming condition of the secondary optical system will be described. A primary electron beam generated by an electron gun is irradiated onto a surface of a wafer (or a substrate) prepared as a sample via a primary optical system (not shown in FIG. 8). Secondary electrons emanate from the wafer surface in response to the irradiation of the electron beam. Those secondary electrons are guided to a secondary optical system by using a combination of a wafer voltage (or a retarding voltage) with a voltage by an electrode located in the secondary optical system. In this step, the secondary electrons are guided so as to satisfy an image forming condition as determined previously in the specific design and thus formed into an image on a detection plane of a detector represented by an EB-CCD. If the potential in the surface of the wafer varies due to the irradiation of the electron beam, the combination of the wafer voltage with the voltage by the electrode located in the secondary optical system could not satisfy the image forming condition as determined previously in the design, and consequently the secondary electrons can not be formed into an image on the detection plane of the detector. To address that, an amount of potential in the wafer surface that would be varied in dependence on the irradiation of the electron beam may be previously superposed on the combination of the wafer voltage with the voltage by the electrode located in the secondary optical system. The primary electron beam generated by the electron gun is irradiated onto the surface of the wafer (or the substrate) prepared as the sample via the primary optical system (not shown in FIG. 8). During this step, the electron beam is irradiated concurrently to a plurality of patterns formed on the substrate consisting of at least two different types of materials or at least two different types of sectional structures. Further, the electron beam is irradiated onto an area larger than a field of view in a mapping optical system. From this wafer surface, the secondary electrons emanate in response to the irradiation of the electron beam. Those secondary electrons are guided to the secondary optical system by means of a combination of the wafer voltage (or the retarding voltage) with the voltage by the electrode located in the secondary optical system. During this step, the secondary electrons are guided so as to satisfy the image forming condition as determined previously in the specific design and formed into an image on the detection plane of the detector represented by the EB-CCD. In this way, when the plurality of patterns formed on the substrate consisting of at least two different types of materials or two different types of sectional structures are irradiated concurrently, the different types of materials or the different types of sectional structures have different amounts of charge-up from one another, and so if the substrate voltage or the retarding voltage is set to the specific charge-up amount in conformity with either one of the materials or sectional structures, then the contrast between the different types of materials or sectional structures on the substrate can be enhanced for image formation. Further, by providing the irradiation of the electron beam onto the area larger than the field of view of the mapping optical system, the symmetry of the image in the X- and Y-directions can be ensured and thus an enlarged image representing realistically an actual image (an actual pattern) can be obtained. Although before the irradiation of the electron beam, the combination of the wafer voltage (or the retarding voltage) of the secondary optical system with the voltage by the electrode located in the secondary optical system is not in conformity with the image forming condition as determined previously in the design, as a change occurs in the potential in the wafer surface by the irradiation of the electron beam, the secondary electrons are due to satisfy the image forming condition for the secondary optical system as determined previously in the design and thus can be formed into an image on the detection plane of the detector. The combination of the wafer voltage with the voltage by the electrode located in the secondary optical system may be set as desired in dependence on the specific type of the sample, such as the substrate and the wafer or the specific material of the surface of the sample in conjunction with a current value or a current density or an energy of the electron beam. The combination of the wafer voltage with the voltage by the electrode located in the secondary optical system may be set so that the secondary electrons, after a number of times of irradiation, can satisfy the image forming condition for the secondary optical system as determined previously in the design. The combination of the wafer voltage with the voltage by the electrode located in the secondary optical system may be set such that for each irradiation of the electron beam, the secondary electrons may satisfy the image forming condition for the secondary optical system as determined previously in the design, so that when the electron beam is irradiated by a number of times, the combination of the wafer voltage with the voltage by the electrode located in the secondary may be controlled for each irradiation of the electron beam such that the secondary electrons can satisfy the image forming condition for the secondary optical system as determined previously in the design. In this case, the images obtained during each time of irradiation may be summed up. When a scanning image is taken by scanning the stage or the electron beam, the combination of the substrate voltage or the retarding voltage with the voltage by the electrode located in the secondary optical system may be controlled in response to the current density or current value of the electron beam and the scanning speed of the stage or electron beam so that the secondary electrons can satisfy the image forming condition for the secondary optical system as determined previously in the design. An embodiment of an overlay inspection method will now be described. First referring to FIG. 9, there is shown a conceptual diagram illustrating an overlay inspection. In FIG. 9, reference numeral 100 designates a silicon substrate, 101 an oxide film layer, 102 an under layer pattern, 103 a deposition film layer, and 104 a resist layer after having been exposed to a light and then developed. A semiconductor manufacturing process involves a number of etching processes. An etching process provides the steps of applying a resist over a deposition film to be desirably etched, for example, the oxide film 103; exposing the resist to a light or an electron beam and then developing it so as to form a desired pattern in the resist layer 104; and etching and thereby removing a portion of the deposition film, for example, the oxide film that is not covered with the resist layer so as to form it into a desired pattern. Over the pattern 102 that has been created in the first etching process (hereinafter used to refer a pattern of an overlay mark), the step of burying or deposition of a new film is applied, and thus formed film will again need to be processed by etching. In this stage, the pattern (an under layer pattern) 102 that has been created in the previous process and a pattern (an upper layer pattern) 105 that will be newly created by etching must be in conformity to each other in accordance with a design. To address this, a mark for alignment is used to inspect the conformity between the under layer pattern 102 and the upper layer pattern 105. Since the resist has been already applied over the under layer pattern for the etching of the upper layer pattern, the under layer pattern needs to be viewed or observed through the resist. Further, the inspection of the overlay requires that the upper layer pattern and the under layer pattern must be viewed or observed simultaneously. In the overlay inspection, primarily the under layer pattern may often reside beneath the resist or the oxide film. Occasionally, it may reside beneath a conductive layer. Primarily, the upper layer pattern may be formed by exposing the resist to a light, which can be accomplished by the exposure only, or by the steps up to the post-baking or up to the development. FIG. 10 shows a conceptual diagram of an inspection area. The overlay inspection may be applied to a limited number of dies, such as D1 to D8 in FIG. 2, for example, but not to every one of the dies. Consequently, in order to reduce the time required for travelling between dies to be inspected, the stage should be accelerated up to its maximum speed for travelling between the dies to be inspected. Referring now to FIG. 11, there is shown a conceptual diagram of an overlay mark arrangement. The overlay mark can be occasionally arranged in each die in such a configuration as shown in FIG. 11. The inspection is occasionally limited to certain marks but not applied to every one of the overlay marks. Therefore, in order to reduce a time required for travelling between the marks, the stage is accelerated to a maximum speed for travelling between the marks. Referring now to FIG. 12, an entire apparatus for implementing a surface inspection method for inspecting a sample surface for any defect or the like on a sample surface according to the present embodiment is designated by reference numeral 1. Since the apparatus of the present embodiment is similar to that of FIG. 1 except that a computer is coupled to both of the stage control unit and the storage unit 41, description on the structure and the operation of common parts is herein omitted. A sample “W”, such as a wafer or a substrate, for example (the following description of the present embodiment is directed to an example using the wafer as the sample) may be securely but removably placed on a wafer holding table 51 in the stage unit 5 having a known structure and function by a known means, such as an electrostatic chuck, for example. The wafer holding table 51 is configured to move serially or in a step-and-repeat manner in at least one direction of two orthogonal axial directions, or X and Y directions. A vibration proofing structure of the vibration isolating bed may be formed from a non-contacting bearing. As shown in detail in FIG. 2, an electron gun 21 of the primary optical system for irradiating a primary electron beam may use an electron gun of a thermionic emission type or a Schottky type. It is to be noted that the electron gun 21 may be separate from the components of the primary optical system. The primary electron beam “B1” emitted from the electron gun 21 will have its configuration shaped properly via a quadrupole lens 22 and the like of the primary optical system and then irradiated onto the surface of the sample or the wafer W placed on the wafer holding table 51. In this stage, the primary electron beam is guided through an ExB filter or a Wien filter 28 comprising an electric field and a magnetic field to the wafer surface. An electron beam may be shaped by the lens of the primary optical system such that a size of an irradiation area on the sample is larger than that of a pattern in the sample surface, especially the pattern size of the overlay pattern. Further, the electron beam is shaped such that it has substantially a circular or elliptical shape and it has generally uniformly distributed beam intensity. The electron beam is irradiated substantially onto a center of the overlay mark. The irradiation of the electron beam onto the sample surface is provided by a blanking electrode (not shown) located in the middle of the primary optical system 2. When the electron beam is to be irradiated onto the sample surface, the voltage at the electrode is set to 0V (zero volt) or to a voltage level required to control the path of the electron beam, and the electron beam is advanced substantially centrically through the primary optical system. If the electron beam is not intended to irradiate the sample surface, a sufficient voltage to divert the electron beam completely out of the primary optical system is applied to the blanking electrode so as to guide the electron beam to an outer wall constituting the primary optical system or a specialized electrode (not shown) or the like to achieve blanking for preventing the electron beam from being irradiated onto the sample surface. FIG. 13 shows an overlay mark or an overlay pattern. The overlay mark may employ a bar-in-bar type or a bar-in-box type pattern. The outer bars represent an under layer pattern below a resist layer and the inner bars or box represent the resist pattern, which may have been undergone the steps up to exposure, exposure and PEB (preheating) or up to development. The under layer pattern may be an STI structure or may be a metal wiring or a trench structure. Secondary electrons “B2” are generated from the surface of the wafer W in response to the irradiation of the primary electron beam, by an amount corresponding to energy of the primary electron beam. Those secondary electrons are accelerated by an electrode located adjacent to the wafer toward the defector side until the secondary electrons have a predetermined amount of kinetic energy. The accelerated secondary electrons B2 go straight through the ExB filter or Wien filter 28 comprising the electric field and the magnetic field as described above, and are guided to the secondary electro-optical system (hereinafter simply referred to as the secondary optical system) 3. In this stage, the wafer surface could have been charged by the irradiation of the primary electron beam, and consequently the secondary electrons may occasionally fail in acceleration to the predetermined amount of kinetic energy. In the event of such a failure, the secondary electrons could not be successfully formed into an image on a detection plane of a detector 41, resulting in no image obtained or an unfocused image. To address this, a charging amount from the electron beam irradiation over the wafer surface should be previously calculated, and a sample voltage or a retarding voltage should be modified adaptively in dependence on the calculated charging amount. This enables the secondary electrons to be accelerated to the predetermined amount of kinetic energy by taking the amount of charging from the electron beam irradiation into account. Secondary electrons are formed into an image on the detector 41 as a map projection image by the secondary optical system 3. The electric lens or electrostatic lens 31, a component of the secondary optical system 3, comprises plural sheets of coaxially located electrodes having apertures or a plurality of electrode groups disposed coaxially, wherein a number of thus configured lenses are arranged in multi-level. The electric lens serves to enlarge image data possessed by the secondary electrons, while guiding it to the detector as map projection data so as not to lose position and surface data on the wafer W. The detector 41 may comprise a MCP (Multi Channel Plate) in conjunction with a fluorescent screen and a TD-CCD or EB-CCD or EB-TDI. The electrons multiplied by the MCP are then converted to light in the fluorescent screen, which light signal is taken by the TDI-CCD and output as an image signal. Alternatively, the secondary electrons may be directly introduced into the EB-CCD for converting into the image signal. It is to be noted that each of the components of the primary and the secondary optical system as well as the detecting system may have a known structure and function, and so any further description should be herein omitted. The stage unit 5 for holding the wafer W may have a structure to provide a serial movement if the detector is the TDI-CCD or the EB-TDI. Further, the stage is structured not only to make a serial movement but also to repeat a go-and-stop motion in case of the detector implemented by the TDI-CCD or the EB-TDI. If the detector is the CCD or the EB-CCD, the stage is also allowed to repeat the go-and-stop motion. The position of the stage is always measured by a laser interferometer, though not shown, in a known method, and a current value of the position given by the measurement from the laser interferometer is compared to a predetermined target value, and based on a resultant residual error, a signal for correcting the residual error is sent to an electrostatic lens control unit (not shown) of the secondary optical system 3. A correction mechanism is provided, in which a moving and stopping motion or a speed fleck and minute vibration during these motions may be corrected by modifying the path of the secondary electrons by means of the electrostatic lens as described above, so that a stable image-forming condition can be always provided on the detection plane of the detector. The stage unit is provided with a brake system (not shown), and the brake system may be used upon stopping of the stage so as to reduce or even eliminate any minute vibration during stopping motion. The electric image data obtained by the detector 4 is input to an image processing unit, though not shown, where signal processing or image analysis is carried out to identify the location of defect and determine the type of defect, and the result may be notified to an observer, while being stored in a storage media. For the overlay inspection, a shift length in the X and Y directions and a shift amount in a rotational angle (θ) between the under layer pattern and the upper layer pattern are calculated from the image analysis to determine whether the overlay is right or wrong. The inspection may be selectively performed in an on-line or off-line inspection, and it is also possible in the on-line inspection method to provide a feedback of an inspection result directly to a semiconductor manufacturing line as an electric signal or the like via a signal line. Further, it is also possible in the off-line inspection method that the inspection result is directly input from a terminal of the inspection apparatus to provide a feedback thereof to the semiconductor manufacturing line as an electric signal or the like via a signal line. The inspection result may be used for quality control in the course of manufacturing process via a communication with a host computer in the semiconductor manufacturing line. Since the operations for loading the wafer W as before the inspection onto the stage unit 5 within the chamber 12 and unloading the wafer W as after the inspection out of the stage unit are similar to those described above with reference to FIG. 1, the detailed description is herein omitted. It is a matter of course that a configuration comprising a plurality (two in this embodiment) of the preparatory environment compartments 62 as shown in FIG. 3 may be applicable to the illustrated embodiment. A Dose amount (referred to as a dosage of the electron beam, representing an amount of irradiated charges as per a unit area over a sample such as a wafer and a substrate, hereinafter referred to as the Dose amount) is calculated from a signal of current density and a blanking signal, and the EB-CCD is controlled by using the blanking signal. The theory for controlling the RTD voltage or the substrate voltage will be as follows, similarly to that in the embodiment above. A current density “Je” can be computed from an electron current value of an electron gun. The Dose amount for the wafer surface can be calculated from the current density Je and a blanking cancellation time “τS” of the blanking signal. Wherein, Dose amount=Je=τS The electrostatic capacity “C” as per unit area in the sample surface, or the wafer surface, can be determined from the data on the wafer surface, for example, a resist thickness “d” and a relative dielectric constant “∈r”. Wherein, C=∈r·∈0/d (unit area is calculated by cm2, ∈0 is a dielectric constant in vacuum) In addition, from CV=Q, a variation in wafer surface voltage ΔV=Q/C, wherein, the wafer surface voltage may be also referred to as a substrate surface voltage or a sample surface voltage, representing a voltage determined by summing up (superposing) an originally applied wafer voltage and a voltage applied through the irradiation of the electron beam to the wafer. On the other hand, the “Q” represents a total amount of electrons irradiated to the wafer surface and assuming that a secondary electron emission rate is denoted by “γ” at the time of landing energy “LE” (keV), thenQ=Dose amount·(1−γ)=Je·τS·(1−γ) Therefore, the variation in wafer surface voltage can be expressed as follows:ΔV=Je·τS·(1−γ)·d/∈r·∈0 Accordingly, the wafer voltage (or the retarding voltage) RTD should be adjusted to satisfyRTD+ΔV=design value (secondary electron drawing voltage). FIG. 14 shows a conceptual diagram of a motion of the stage. The description will be given to the stage motion in a case where the EB-TDI or the TDI is employed as the detector for image-taking operation. The stage is accelerated up to a maximum speed until it reaches the position of the overlay mark as determined previously, and then in the overlay mark region, the stage is moved at a speed in synchronism with an operating frequency of the EB-TDI or the TDI for taking an image of the overlay mark. Further, when moving to another overlay mark, the stage is moved while being accelerated. A step-and-repeat motion is performed for taking an image by the EB-CCD or the CCD. It is to be noted that to take an image of the overlay mark, the same overlay mark may be used repeatedly by a number of times for image-taking. For the overlay inspection, there may be a case where the condition to determine the ΔV for viewing the under layer pattern is different from the condition to determine the ΔV for viewing the upper layer pattern. Since in this case, it is impossible to obtain the upper layer pattern and the under layer pattern at the same time, the image taking operation is carried out a number of times to thereby obtain the lower layer pattern and the upper layer pattern separately, and those images are combined to form a synthetic image, from which any misalignment between the under layer pattern and the upper layer pattern may be detected or calculated. In this operation, the same pattern may be repeatedly used for image-taking. Alternatively, the repeated image taking may be applied to each die repeatedly or may be applied to each wafer repeatedly. To do this, preferably the conditions for obtaining an image, especially the RTD and the Dose amount, may be set to the conditions suitable for the under layer pattern. Especially, there may be a case where the sectional structure or the material of the substrate surface and thus a time period for charging and a time period for the charges in the surface to escape (discharging period) are different from each other in dependence on the specific process. In such a case, even if a single pattern is subject to image-taking, the pattern may be subject to image-taking with a time difference rather than repeated serial operations. Turning now to FIGS. 15(A) and 15(B), the theory of the overlay image-taking will be described. In FIGS. 15(A) and 15(B), respectively, the vertical axis indicates a potential in the surface of the sample or the wafer and the horizontal axis indicates a time elapsed since the beginning of the electron beam irradiation. The description is herein directed to the image-taking by a single irradiation as shown in FIG. 15(A). If an amount of irradiation of electrons is increased for the image-taking to be accomplished by a single irradiation, the potential in the wafer surface could rise to V6 within a charging period determined in dependence on a feature of the wafer surface. Assuming that the condition for forming the secondary electrons from the wafer surface into an image by adjusting the surface potential and the RTD is V3, then in the single image-taking operation as shown in FIG. 15(A), the surface potential of the wafer would exceed the level of the image forming condition before the image being taken, resulting in only an unfocused image or no image obtained. Further, if the amount of irradiation (i.e., dose) of electrons is decreased in order to make the final surface (V6) to V3 by being charged, an amount of secondary electrons is decreased, and accordingly a resultant image would be dark or no image would be obtained. In contrast to that, when the irradiation of electron beam is given little by little with some interval between irradiations, as shown in FIG. 15(B), the wafer surface potential can be discharged during the interval between respective irradiations, so that the potential in the wafer surface can be controlled by taking advantage of the charging and discharging from the irradiation to thereby make it possible to take an image at a specific timing that can produce V3 representing the image forming condition. The above approach is illustrated in a conceptual diagram in FIG. 16. This shows an example of an operation for such a substrate that requires a longer time for discharging so that the surface potential is not easily attenuated, in which if the repeated image taking operations are carried out continuously, the surface potential would vary quickly and significantly and thus the RTD adjustment could not provide sufficient effect to satisfy the image forming condition of the secondary EO (Electro-Optic) system or of the secondary optical system which provides the image forming condition of the secondary electrons on the detector surface. After taking an image of pattern (i.e., a pattern of an overlay mark formed in a die, which will be used in the reference) 1 in a die 1 by a single time, the operation process is moved to a pattern 2 in a die 2 for taking an image thereof by a single time, and then moved to a pattern 3 in a die 3 for taking an image thereof by a single time, followed by taking images of a plurality of dies including die 4, a die 5 . . . and a die n, each by a single time, and after a series of image-taking of every die of n dies each by single time having been completed, the operation process returns back to the pattern 1 of the die 1 for a second image-taking. Each second image-taking is applied to the die 2, the die 3 . . . and the die n, and in this way, this operation is repeated by m times as required. In this regard, any misalignment between the upper layer pattern and the under layer pattern may be calculated from a synthetic image from the image taken in the first image-taking and the image taken in the second image-taking, in which the images to be used to form the synthetic image may be those taken at any time of the image-taking operation as desired. Although FIG. 16 shows an example where the image-taking operation is conducted while moving from one die to another die, if images of a plurality of patterns within a single die are to be taken, then a plurality of image-taking operations may be carried out while moving from one pattern to another pattern within the die. Again in this case, any misalignment between the upper layer pattern and the under layer pattern may be calculated from a synthetic image from the image taken in the first operation and the image taken in the second operation, in which the images to be used to form the synthetic image may be those taken at any time of image-taking operation as desired. As shown in FIG. 16, if the image-taking of one pattern is repeated by a number of times, as moving from one pattern to another pattern, preferably the apparatus may have a function for controlling a speed of the stage so that a distance of stage movement should be minimized and a time required for moving the stage should be equal among all movements (the interval between image-taking of respective patterns should be made constant). If there are a large number of patterns to be inspected, the patterns may be organized into groups of a desired number of patterns so as to conduct the image-taking on a group-by-group basis, rather than taking images of all patterns at once. Preferably, the n number of patterns contained in the group may be determined from a time difference (or an interval period) required for image-taking and a moving speed of the stage, as calculated from the feature regarding the charging period and the discharging period of the substrate. The feature regarding the charging period and the discharging period of the substrate is input previously into the control unit for controlling the movement of the stage, which will be combined with the position data of the pattern to be inspected for calculating the condition where the distance or time period of movement between patterns can be minimized and the period of movement between patterns is equal among all patterns. Further, the feature regarding the charging period and the discharging period of the substrate is input previously into the control unit for controlling the movement of the stage, which will be combined with the position data of the pattern to be inspected for calculating a specific number of patterns to be required for inspection and calculating the condition where the inspection time can be minimized and the period of movement between patterns is equal among all patterns. Specifically, the procedure will be carried out in the following steps. First of all, the discharging period from a point of time when the electron beam is irradiated onto the wafer until the charge amount in the wafer surface becomes 0 or a predetermined value is measured. Then, a number or positions of the overlay marks subject to image-taking, or the groups of overlay marks subject to image-taking are determined based on the calculated discharging period as stated above. Specifically, as described above, since in the illustrated embodiment, a contrast suitable for image-taking can be obtained by repeating several times a series of operations in which the irradiation of the electron beam is applied to the overlay mark at a single location and before the charge amount in the wafer surface becomes 0 or the predetermined value, another electron beam irradiation to the same overlay mark is carried out, therefore it is required to adjust the time interval from the first irradiation of the electron beam to the predetermined overlay mark to the second irradiation of the electron beam to the same overlay mark so as not to exceed the discharging time period. Secondly, the period for moving between overlays should be adjusted equally. This yields an equal time interval between one irradiation and another of the electron beam to each overlay and thus the equal charge amount in each overlay results in a homogeneous image taken for each overlay. To adjust the moving period, the highest moving speed of the stage is taken as a reference. In the illustrated embodiment, the overlays to be measured are previously determined, and the moving period taken in the case to move the stage by the longest moving distance between two of those determined overlays at the highest speed has been taken as a reference (the moving period in this case is referred to as a reference moving period). Then, the stage moving speed between the respective overlays may be set such that the moving period for between respective overlays should be equal to the reference moving period. If a sum of the moving periods obtained in the above procedure exceeds the discharging period, the selection of the overlays should be made again. In another embodiment, every combination of the moving distances between the overlay marks as well as the maximum moving speed of the stage are previously stored in the storage media in an apparatus, and the discharging period is input through the input section in the apparatus, so that the computing section in the apparatus may execute an operation to determine a path to allow the maximum number of overlays to be subject to the image-taking operation within a range not exceeding the discharging period of the wafer surface or the time determined by subtracting a desired time period from the discharging period. Further, there would be a case where the moving speed or the acceleration varies along respective axes, such as along the X- or Y-axis, or depending on each specific position along the axes in accordance with a configuration of the stage, and in such a case, the variation should be taken into account for calculating or computing the moving period. When the images of the upper and the under layer patterns are taken separately from each other, the RTD should be controlled in dependence on the Dose amount. Irradiation of laser light may be employed as a method for controlling the ΔV. This irradiation of the laser light can provide a more precise control for a surface potential increment. The laser light is irradiated in advance and then the electron beam is irradiated. The surface potential increment has been modified by a quantum effect from the irradiation of the laser light, and the surface potential increment in the sample surface, which could not have been fine-tuned simply through the Dose amount control, can be now successfully tuned, so that a clearer image can be obtained. The surface potential tuning by the irradiation of the laser light and the adjustment of the RTD and the Dose amount can be provided by controlling these three factors together in a comprehensive manner and concurrently. Although it is possible to apply the integration by all images in case of repeated image taking, alternatively the upper layer pattern image and the under layer pattern image may be taken separately, wherein the laser light irradiation amount and the potential increment in the sample surface can be fine-tuned only when taking the under layer pattern image. Alternatively, the potential increment in the sample surface by the irradiation of the laser light may be fine-tuned when taking the image of the upper layer pattern, or the laser light irradiation may be provided at any times. Further, the laser light irradiation may be provided during no image being taken, but it is suspended or blocked during the image taking. Referring now to FIG. 17, a sample inspection apparatus according to another embodiment of the present invention is generally shows by reference numeral 1a. In the inspection apparatus 1a, an electron gun 21a of a thermionic emission type or a Schottky type for irradiating an electron beam onto the wafer is located right above a stage unit 5a. A primary electron beam B1 emitted from the electron gun is irradiated onto a wafer surface, while its beam configuration being shaped through a primary optical system 2a comprising an electrostatic lens 22a, such as a quadrupole lens and the like. The primary electron beam is irradiated onto an overlay mark, while being driven to make a scanning operation in the X- and the Y-directions. Same as the foregoing embodiment, the wafer may be securely but removably placed on a wafer holding table 51 in the stage unit 5 having a known structure and function by a known means, such as a vacuum chuck, for example. The wafer holding table 51 is configured to move serially or in a step-and-repeat manner in at least one direction of two orthogonal axial directions, or X and Y directions. A vibration proofing structure of the vibration isolating bed may be formed from a non-contacting bearing. Secondary electrons B2 are generated from the surface of the wafer in response to the irradiation of the electron beam, by an amount corresponding to energy of the primary electron beam. Those secondary electrons are accelerated by an adjacent electrode until the secondary electrons have a predetermined amount of kinetic energy and then guided to a detector 41a via a secondary optical system, though not shown. In this stage, the wafer surface could have been charged by the irradiation of the electron beam, and consequently the secondary electrons may occasionally fail in acceleration to the predetermined amount of kinetic energy as designed. In the event of such a failure, no image or an unfocused image could be obtained. To address this, as applied in the foregoing embodiment, a charging amount from the electron beam irradiation over the wafer surface should be previously calculated, and the substrate voltage or the retarding voltage should be modified adaptively in dependence on the calculated charging amount. This enables the secondary electrons to be accelerated to the predetermined amount of kinetic energy by taking the amount of charging from the electron beam irradiation into account. Processing of the image detected by the detector may be carried out in a similar manner to that described in the foregoing embodiment, and any detailed description should be herein omitted. Operations for loading the wafer W as before the inspection onto the stage unit 5a within the chamber 12 and unloading the wafer W as after the inspection are similar to the operations in the foregoing embodiment, and the description will be herein omitted. FIG. 18 shows yet another example of the present invention. FIG. 18 depicts a processing apparatus using a charged particle beam, in which the movement of the stage as shown in FIG. 16 is also applicable to a case for processing a material, such as an insulating material, that is easily charged and associated with a problem of precision of processing arising from being charged. If the work piece is easily charged and consequently could not be processed in a single operation with a high energy density, then it is processed with a lower energy density. If there are a number of work pieces, the process may make use of a time waiting for a first work piece to be discharged so as to move to a second work piece and process during this waiting period. Although FIG. 18 shows an example of a charged particle beam, an energy particle beam including, for example, a high-speed atomic beam, or an energy beam including, for example, a laser, a maser and an X-ray may be used instead of the charged particle beam. It is to be noted that since the configuration and operations of the processing apparatus may be similar to those in the conventional ones with an exception of its pattern inspection apparatus and inspection method according to the present invention, any detailed description on those will be herein omitted. Yet another embodiment of a sample surface inspection method according to the present invention will now be described. A conceptual diagram of the overlay inspection is similar to the illustration of FIG. 9 and the description on that will be omitted. Further, since the apparatus used in this embodiment is similar to that shown in FIG. 1, the description will be given again with reference to FIG. 1. In FIG. 1, an entire apparatus for implementing a surface inspection method for inspecting a sample surface for any defect and so on is shown with reference numeral 1. In FIG. 1, reference numeral 2 designates a primary electro-optical system (hereinafter, simply referred to as a primary optical system), 3 a secondary electro-optical system (hereinafter, simply referred to as a secondary optical system), 4 a detection system, 5 a stage unit disposed on a vibration isolating bed having a known structure, all of which are contained in a housing 11 defining a chamber 12. The chamber 12 is constructed such that it can be controlled to have a desired atmosphere, a vacuum atmosphere, for example, by a device though not shown. A sample “W”, such as a wafer or a substrate, for example (the following description of the present embodiment is directed to an example using the wafer as the sample) may be securely but removably placed on a wafer holding table 51 in the stage unit 5 having a known structure and function by a known means, such as a chuck, for example. The wafer holding table 51 is configured to move serially or in a step-and-repeat manner in at least one direction of two orthogonal axial directions, or X and Y directions. A vibration proofing structure of the vibration isolating bed may be formed from a non-contacting bearing. The electron gun 21 of the primary optical system for irradiating a primary electron beam may use an electron gun of a thermionic emission type or a Schottky type. It is to be noted that the electron gun may be a separate component from the primary optical system. The primary electron beam B1 emitted from the electron gun 21 is irradiated onto the surface of the sample or the wafer W placed on the wafer holding table 51 while being shaped in its configuration properly via the primary optical system 2 comprising an electrostatic lens, such as a quadrupole lens 22 and the like. An electromagnetic lens may be used in addition to the electrostatic lens such as the quadrupole lens for shaping the electron beam. In FIG. 19, there is shown a conceptual diagram for shaping the beam configuration by using additionally a shielding element having an aperture or an opening of a desired geometry, such as an aperture member 26. The quadrupole lens has been applied in advance with a voltage so as to form the beam into a desired beam size and geometry which are predetermined. The configuration of the aperture has been also selected to be suitable for forming the beam into the desired beam size and geometry which are predetermined. It is also possible to provide a plurality of aperture members, each having a different configuration, which will be exchangeably used in accordance with the specific type of wafer or inspection pattern. The voltage applied to the quadrupole lens may be also varied in dependence on the specific type of wafer or inspection pattern. Those may be controlled by a control unit for controlling the bean configuration, which is capable of calculating the condition automatically to determine a combination of the voltage applied to the quadrupole lens with the configuration of the aperture. It is possible to shape the beam configuration only with a rectangular aperture. In this case, the beam configuration is controlled by the control unit operable to control the beam configuration in accordance with the specific type of wafer or inspection pattern, in which the control unit calculates a condition automatically for selecting an optimal aperture. Further, the configuration of the aperture may be an elliptical shape in addition to the rectangular shape. In this stage, the primary electron beam is guided through an ExB filter or a Wien filter 28 comprising an electric field and a magnetic field, to the wafer surface. The electron beam is formed into the beam sized to be larger than the size of the pattern in the sample surface, especially of the overlay pattern. The electron beam is formed to achieve a generally uniform distribution of the beam intensity. The electron beam is irradiated substantially to a center of the overlay mark. The irradiation of the electron beam onto the sample surface is controlled by a blanking electrode 23 located in the middle of the primary optical system 2, as shown in FIG. 20. When the electron beam is to be irradiated onto the sample surface, the voltage at the electrode is set to 0V (zero volt) or to a voltage level required to control the path of the electron beam, and the electron beam is advanced substantially centrically through the primary optical system. If the electron beam is not intended to irradiate the sample surface, a sufficient voltage to divert the electron beam completely out of the primary optical system is applied to the blanking electrode 23 so as to guide the electron beam to an outer wall constituting the primary optical system or a specialized electrode 24 or the like to achieve blanking for preventing the electron beam from being irradiated onto the sample surface. The blanking electrode may be constructed from a quadrupole electrode. The direction for deflecting the electron beam may be either of the orthogonally crossing X direction or Y direction, or the diagonal direction (including an X-directional component and an Y-directional component). The blanking electrode 23 may comprise a quadrupole electrode. FIG. 21 shows a conceptual diagram of the direction for deflecting the electron beam. In FIG. 21, “IP” designates a pattern to be inspected including an under layer pattern 102 and an upper layer pattern, and “BA” designates an irradiation range of the primary electron beam. Preferably, the direction for deflecting the electron beam may be either in the heading direction of the stage or the opposite direction thereto. The direction for deflecting the electron beam may be any desired direction relative to the heading direction of the stage. Since the overlay mark or the overlay pattern used in the illustrated embodiment is similar to that shown in FIG. 13, and the explanation thereof is herein omitted. Secondary electrons “B2” are generated from the surface of the wafer W in response to the irradiation of the primary electron beam, by an amount corresponding to energy of the primary electron beam. Those secondary electrons are accelerated by an electrode located adjacent to the wafer toward the defector side until the secondary electrons have a predetermined amount of kinetic energy. The accelerated secondary electrons B2 go straight through the ExB filter or Wien filter 28 comprising the electric field and the magnetic field as described above, and are guided to the secondary electro-optical system (hereinafter simply referred to as the secondary optical system) 3. In this stage, the wafer surface could have been charged by the irradiation of the primary electron beam, and consequently the secondary electrons may occasionally fail in acceleration to the predetermined amount of kinetic energy. In the event of such a failure, the secondary electrons could not be successfully formed into an image on a detection plane of a detector 41, resulting in no image obtained or an unfocused image. To address this, a charging amount from the electron beam irradiation over the wafer surface should be previously calculated to determine a beam size and a shape thereof. This enables the secondary electrons to be accelerated to the predetermined amount of kinetic energy by taking the amount of charging from the electron beam irradiation into account. Secondary electrons are formed into an image on the detector 41 as a map projection image by the secondary optical system 3. The electric lens or electrostatic lens 31, a component of the secondary optical system 3, comprises plural sheets of coaxially located electrodes having apertures or a plurality of electrode groups disposed coaxially, wherein a number of thus configured lenses are arranged in multi-level. The electric lens serves to enlarge image data possessed by the secondary electrons, while guiding it to the detector as map projection data so as not to lose position and surface data on the wafer W. The detector 41 may comprise a MCP (Multi Channel Plate) in conjunction with a fluorescent screen and a TD-CCD or EB-CCD or EB-TDI. The electrons multiplied by the MCP are then converted to light in the fluorescent screen, which light signal is taken by the TDI-CCD and output as an image signal. Alternatively, the secondary electrons may be directly introduced into the EB-CCD for converting into the image signal. It is to be noted that each of the components of the primary and the secondary optical system as well as the detecting system may have a known structure and function, and so any further description should be herein omitted. Further, the secondary electrons after having been multiplied by the MCP may be introduced directly into the EB-TDI. In addition, the fluorescent screen along with the TDI may construct the detector. The stage unit 5 for holding the wafer W may have a structure to provide a serial movement if the detector is the TDI-CCD or the EB-TDI. Further, the stage is structured not only to make a serial movement but also to repeat a go-and-stop motion in case of the detector implemented by the TDI-CCD or the EB-TDI. If the detector is the CCD or the EB-CCD, the stage is also allowed to repeat the go-and-stop motion. The position of the stage is always measured by a laser interferometer, though not shown, in a known method, and a current value of the position given by the measurement from the laser interferometer is compared to a predetermined target value, and based on a resultant residual error, a signal for correcting the residual error is sent to an electrostatic lens control unit (not shown) of the secondary optical system 3. A correction mechanism is provided, in which a moving and stopping motion or a speed fleck and minute vibration during these motions may be corrected by modifying the path of the secondary electrons by means of the electrostatic lens as described above, so that a stable image-forming condition can be always provided on the detection plane of the detector. The stage unit is provided with a brake system (not shown), and the brake system may be used upon stopping of the stage so as to reduce or even eliminate any minute vibration during stopping motion. The electric image data obtained by the detector 4 is input to an image processing unit, though not shown, where signal processing or image analysis is carried out to identify the location of defect and determine the type of defect, and the result may be notified to an observer, while being stored in a storage media. For the overlay inspection, a shift length in the X and Y directions and a shift amount in a rotational angle (θ) between the under layer pattern and the upper layer pattern are calculated from the image analysis to determine whether the overlay is right or wrong. The inspection may be selectively performed in an on-line or off-line inspection, and it is also possible in the on-line inspection method to provide a feedback of an inspection result directly to a semiconductor manufacturing line as an electric signal or the like via a signal line. Further, it is also possible in the off-line inspection method that the inspection result is directly input from a terminal of the inspection apparatus to provide a feedback thereof to the semiconductor manufacturing line as an electric signal or the like via a signal line. The inspection result may be used for quality control in the course of manufacturing process via a communication with a host computer in the semiconductor manufacturing line. With reference to FIG. 1, the description is now directed to an operation for loading the wafer W as before the inspection onto the stage unit 5 within the chamber 12 and unloading the wafer W as after the inspection from the stage unit. A preparatory environment compartment 62 located adjacent to the chamber 12 of the sample surface inspection apparatus 1 is configured such that in the semiconductor manufacturing process, an environment associated with the wafer carried in from the outside is altered to an environment existing inside the chamber 12 where the stage unit 5 with the wafer holding table 51 is located, until the environment within the preparatory environment compartment 62 is in conformity with the environment inside the chamber 12 to allow the wafer as before the inspection to be carried in from the preparatory environment compartment 62 onto the wafer holding table. Specifically, a gate valve 63 is disposed between the housing 11 and a housing 61. The housing 11 defines the chamber 12 containing the vibration isolating bed having a known vibration proofing structure, and the stage unit 5 having the wafer holding table 51. The stage unit 5 is disposed on the vibration isolating bed. The housing 61 defines the preparatory environment compartment 62. The chamber 12 and the preparatory environment compartment 62 can be selectively placed in communication with each other or blocked from each other, via the gate valve 53. In addition, another gate valve or flange may be arranged in order to introduce, into the preparatory environment compartment, the wafer in the chamber and the preparatory environment compartment 62. In this regard, when the wafer is transferred between the preparatory environment compartment 62 and the chamber 12 through the gate valve 63, the environments inside both of the chamber and the compartment are kept substantially equal (e.g., in a vacuum atmosphere at a degree of vacuum around 10−4 Pa to 10−6 Pa). Since in the semiconductor manufacturing process, the wafer subject to the inspection before being transferred to a subsequent step is held in an environment suitable for a transfer to the subsequent step, the preparatory environment compartment is firstly controlled to achieve the environment for transferring the wafer to the subsequent step in a known manner by means of a gas supply unit (not shown) and a vacuum evacuation unit, both having a known structure. Once the environment for transferring the wafer to the subsequent step and the environment inside the preparatory environment compartment (vacuum condition) have become equal, the another valve or flange operable to introduce the wafer into the preparatory environment compartment is opened to allow the wafer to be introduced into the preparatory environment compartment 62, where the vacuum evacuation system or the gas supply unit as mentioned above is controlled to now achieve the same environment (vacuum condition) as the environment in which the wafer holding table 51 is located or inside the chamber 12. After that, the gate valve 63 for isolating the chamber 12 from the preparatory environment compartment 62 is opened to allow the wafer W as before the inspection to be transferred onto the wafer holding table 51 (this step referred to as loading). After the transfer of the wafer as before the inspection having been completed, the gate valve 63 is closed, and the environment in which the wafer holding table is located is adjusted to be suitable for the inspection and then the inspection is started. When the wafer having finished with the inspection is carried out of the wafer holding table 51 (the operation referred to as unloading) and transferred to the subsequent step, the operation may be carried out in an inverse order to the loading. In this regard, preferably the vacuum evacuation unit may be implemented by a combination of a turbo-molecular pump 66 with a dry-root pump 67 as shown in FIG. 1, but a rotary pump equipped with an oil mist trap or a molecular sieve may be used instead of the dry-root pump. A configuration comprising a plurality (two in this case) of preparatory environment compartment 62 as shown in FIG. 3 is also applicable to the illustrated embodiment. A certain level of irradiation of the electrons onto the surface is required in order to obtain a capacity contrast on the surface. To obtain this required irradiation amount (referred hereinafter to as a required Dose amount) of electron beam, the present invention is characterized in having an irradiation shape of the electron beam with a long beam length along a scanning direction of the stage relative to the pattern to be inspected. The length of the beam is determined by the required Dose amount. The required Dose amount may be controlled to achieve the best contract between an outer pattern and an inner pattern, and may be determined in dependence on the specific stage speed and the current density. The geometry, material, sectional structure and the like of the surface of each specific wafer may be input, and the beam length may be determined from the input data and applied. In that case,Beam length X0=Hz·Cwf·ΔV/Je where: Hz: Operating frequency of TDI (stage speed) Cwf: Electrostatic capacity of wafer surface determined in dependence on the sectional structure, surface material and the like of the wafer, which may be determined, as follows: by way of example, assuming that a wafer having been applied with the resist by the resist thickness of “d”, and the relative dielectric constant of the resist is denoted by ∈r and the dielectric constant in vacuum is denoted by ∈0, thenCwf=d/(∈r·∈0)ΔV=VEO−VRTD EEO: Drawing voltage of secondary electrons VRTD: Substrate voltage or retarding voltage Je: Irradiated current density to substrate. Owing to the deflection (blanking) of the electron beam, the sample surface is subject to the irradiation of the electron beam having a slightly high density of distribution in the direction of the deflected electron beam. This may lead to a small bias in the charged condition over the sample surface. To address that, a correction of the Dose amount may be applied via the blanking. To do so, an amount of correction is calculated with the blanking direction aligned with the scanning direction, and a required Dose amount by “X0” is determined. The blanking direction may be the stage scanning direction or the direction opposite the stage scanning direction. Assuming that the term of correction for the X0 via the blanking is denoted by “XB”, the blanking time by “τB”, and the distance for the beam to move on the substrate surface by “L”, thenXB=Hz·L·τB, andthe beam length X0 after the correction by the blanking will be given byX0=Hz·Cwf·ΔV/Je±XB (It is to be noted that the sign ± depends on the blanking direction, where the + designates the blanking direction opposite the heading direction of the stage. The sign − designates the blanking direction in conformity with the heading direction of the stage.) Further, the correction for the required Dose amount by the blanking may be provided by the control to the substrate voltage or the retarding voltage for controlling the increment of the substrate surface potential. In this case, the voltage adjustment ΔVB will be given byΔVB=Je·τB/Cwf In order to reduce the correction amount for the required Dose amount by blanking; the blanking direction may be set to be perpendicular to the heading direction of the stage. Further, if there is no need for correction on the required Dose amount by blanking to be taken into account; the blanking direction may be in any desired directions. The beam length may be changed for each specific wafer, or may be changed depending on the sectional structure of the specific pattern to be inspected or the specific material of the surface. For example, data on the beam length may be previously included in a recipe, so that when the wafer is loaded, the beam length may be determined to be suitable for that specific wafer or pattern to be inspected. FIG. 22 shows a physical relationship between the irradiated electron beam and the pattern to be inspected. In FIG. 22, the region indicated with the cross-hatching represents the irradiation area by the electron beam and the size of the area. Although in the illustrated example, the irradiation area assumes a geometry with arched upper and lower edges and straight left and right edges, the area may have a rectangular shape or an elliptic shape that is elongated along the moving direction of the stage. As the beam starts to irradiate the pattern to be inspected and at the time when the pattern to be inspected has moved by X0, the pattern to be inspected can pass across and under the TDI sensor. Using this timing, the TDI sensor starts importing of the image. In this way, the beam irradiation begins at the position by the distance X0 away from the location of the TDI sensor, and the required Dose amount for the image-taking would be given to the pattern to be inspected during the stage being moved by the distance X0. FIG. 23 shows another irradiation example. Depending on the arrangement of the pattern to be inspected, the X0 may be set to be a half of that calculated from the required Dose amount, and in that case the stage may be moved in a turn-back manner. In the illustrated example, the region indicated with the cross-hatching represents the irradiation area by the electron beam and the size of the area. The beam irradiation begins at the position by (½)/·X0 away from the location of the TDI sensor, the stage turns back after having moved by (½)/·X0, and the stage again moves by (½)/·X0, where the image-taking is executed by the TDI sensor. This allows the Dose amount equal to that given by the X0 movement to be provided to the pattern to be inspected. In this approach, if the pattern to be inspected subsequently to the pattern to be inspected first is located downstream to the first pattern, or located at a position opposite to the moving direction of the stage required for the first inspection, then the distance for the stage to travel should be cut by half, contributing to time saving. The field of view for image-taking comprises a pixel number of the TDI, 512 pix in the X direction (identical to the scanning direction of the stage in the illustrated example) and 2048 pix in the Y direction, in which data integration by 512 pix is configured, while the stage providing the X-directional scanning. The beam is configured to be elongated toward the upstream side along the X direction of the field of view, and the region where the TDI imports the image has been already given the required Dose amount by this elongated electron beam thereby allowing the TDI to obtain the image of the pattern to be inspected. In this stage, the Y-directional dimension (beam width) of the irradiated beam may be any dimension (width) as desired depending on the dimension of the pattern to be inspected. If the larger pattern is inspected by using a low magnification factor, the beam width may be sized larger than the Y-directional pixel size (e.g., 2048 pix) of the TDI, while on the other hand, if the smaller pattern is inspected by using a high magnification factor, the beam width may be sized smaller than the Y-directional pixel size (e.g., 2048 pix) of the TDI. Determining the beam diameter as described above can provide a more efficient image-taking of the overlay marks and patterns, especially for an arrangement of the overlay marks or patterns that are aligned side by side in a certain direction. Specifically, the pattern subject to image-taking is applied with the irradiation of the primary electron since before the timing for image-taking (this scanning referred to as Pre-Dose), so that the pattern subject to image-taking should have been charged sufficiently at the time of taking an image of the pattern. If the patterns subject to image-taking are disposed serially along a certain direction, and if the beam diameter is determined in association with the moving of the stage as in the present invention, then each of the patterns subject to image-taking would be ready as they have been charged equally for image-taking. Specifically, if the image-taking is carried out simply by taking the distance between patterns subject to image-taking and the stage speed into account, while moving the stage at a constant speed, an image of the pattern subject to image-taking that would have been held in an optimal charged condition can be taken successfully without the need to stop the stage each time at the location of the pattern subject to image-taking and stay there until the pattern subject to image-taking is charged to a constant charge amount, as is the case with the stop-and-repeat approach. Referring now to FIG. 24, there is shown an example for measuring a distribution of lens aberration of an exposure unit with an inspection apparatus using an electron beam. FIG. 24 shows an example of a pattern distribution for lens aberration research. A set of isolated pattern is used as the pattern for research, and a required number of patterns for lens aberration research is lined up at a space as required therebetween. The set of patterns is transferred onto a sample surface by the exposure unit, and any offset of that set of patterns is examined to study the distribution of the lens aberration. In the illustrated example, the electron beam was irradiated onto the pattern over a large area, and the image is taken serially with the TDI or the EB-TDI, while providing a scanning operation by the stage or the beam. Since the overlay mark in the layers of a product is not applied to every one of the chips, therefore the image is taken by repeating the process of step-and-repeat, while moving to the pattern section required to take a stationary image by the CCD or the EB-CCD using the electron beam having a larger area to irradiate the pattern. In that case, the image may be taken in the Still-mode of the TDI or the EB-TDI. Further, only the pattern section may be scanned for taking an image.
056687281	description	BEST MODE FOR CARRYING OUT THE INVENTION Referring now to the drawing figures, particularly to FIG. 1, there is illustrated a fuel bundle, generally designated B, including a plurality of full-length fuel rods 20 and part-length fuel rods 22. Full-length fuel rods 20 extend the full distance between a lower tie plate 14 and an upper tie plate 16. It will be appreciated that the part-length fuel rods 22 extend from the lower tie plate 14, terminating in the fuel bundle B short of the upper tie plate 16. A plurality of spacers are provided along the length of the fuel bundle, spacers S4 and S5 being illustrated. A channel C also surrounds the matrix of full and partial length fuel rods, as well as the spacers, for confining the liquid flow through the fuel bundle. It will be appreciated that the part-length fuel rods terminate shod of the upper tie plate to define one or more steam vent volumes between the part-length fuel rods and the upper tie plate. For example, four groups of part-length fuel rods 22 of four rods each are illustrated in FIG. 1 defining four steam vent volumes designated as V1-V4. While a 10.times.10 array of fuel rods is illustrated in FIG. 1, it will be appreciated that other arrays of fuel rods may be employed with the present invention, for example, a 9.times.9 array and that other combinations of part-length and full-length fuel rods at various locations within the fuel bundle can be provided. Additionally, deflectors D are illustrated in FIG. 1 at lateral and axial locations within the fuel bundle and above the groups of part-length fuel rods, respectively. It will be appreciated, however, that a single deflector D or string of deflectors can be used in the fuel bundle, for example, at a centrally located position as illustrated in the embodiment of FIGS. 3 and 4 where the part-length rods are disposed only in the central portion of the bundle. As illustrated in FIGS. 1 and 2, the part-length fuel rods may lie in groups of four such rods with deflectors D disposed above the upper ends of those groups of rods, respectively. As illustrated in FIGS. 3-5, the part-length fuel rods 20 may be centrally disposed within the fuel bundle, for example, in a 4.times.4 array, with surrounding fuel rods being symmetrically disposed about the part-length rods 20. Each steam vent region V above a group of part-length rods is thus void of nuclear material and forms a volume for venting steam upwardly within the bundle for flow out of the bundle, e.g., for driving a turbine to generate electricity. It will be appreciated that improved critical power is obtained by maintaining high-density liquid in the interstices of the full-length fuel rods, particularly in the upper two-phase region of the nuclear fuel bundle including the region above the upper ends of the part-length rods. Thus, it is desirable to deflect liquid flowing upwardly within the fuel bundle into the interstices of the full-length rods, while simultaneously providing a path for steam to vent from the fuel bundle. To accomplish this in a fuel bundle employing part-length fuel rods, deflector D is disposed over the upper ends of the part-length rods 22 as illustrated in FIGS. 1-5. As will be seen in FIGS. 3 and 5, the part-length rods are supported in a spacer, for example, spacer S5, and terminate slightly above the spacer. The deflector D may be disposed just above and at distributed locations above the ends of the part-length rods 22 for deflecting liquid passing upwardly within the interstices of the part-length fuel rods 22 laterally outwardly into the interstices of the full-length fuel rods. By deflecting the liquid laterally, the liquid has a tendency to stay within the interstitial volumes of the full-length fuel rods, while the lower density steam may flow therefrom into the steam vent region V above deflector D for flow upwardly and out of the fuel bundle. To locate the deflector D in the fuel bundle, clips 24 are provided on the spacer S5 to maintain the deflector D in position to deflect the liquid laterally outwardly. The deflector D can be removed from the clips and the bundle, providing full access to the part-length rods 22. While the deflector can be releasably supported solely from a spacer, a structural support rod 32 provides support for the deflector 30 from the upper tie plate 16. In this manner, the deflector may be withdrawn through a correspondingly shaped opening in the upper tie plate to provide access to the part-length fuel rods. The deflector 30 may also be releasably supported by a combination of support rod 32 and clips releasably securing the deflector to the spacer. In FIGS. 1 and 2, the deflectors D may comprise flat plates P1-P4 disposed over the upper ends of the groups of part-length fuel rods 22. The deflector plates P1-P4 likewise deflect fluid issuing from the interstices of the part-length fuel rods laterally outwardly into the interstices of the full-length fuel rods. Referring now to FIGS. 6 and 7, the deflector D may be configured other than as a flat plate, particularly to minimize the pressure drop and to improve liquid deflection effectiveness. For example, i FIGS. 6 and 7, a generally inverted pyramidal-shaped deflector 30 is disposed in the steam vent volume V above the upper ends of the part-length fuel rods 22. It will be appreciated that the steam vent volume V defined within the confines of surrounding full-length rods is essentially four-sided and, consequently, the pyramidal-shaped deflector 30 may be inverted and disposed within that rectilinear volume. In FIGS. 8 and 9, a similar inverted pyramidal-shaped deflector 34 is provided. However, the deflector 34 is rotated about a vertical axis about 45.degree. (as compared with the deflector of FIG. 6 and 7) so that the flat triangular sides lie in opposition to the corners of the is rectilinear-shaped steam vent volume V. Thus, the generally triangular-shaped surfaces of deflector 34 are extended upwardly from their bases to fill in the corner areas of the steam vent volume V whereby the horizontally-projected area of the deflector 34 is substantially coextensive with the horizontal rectilinear area of the steam vent path. Liquid flowing upwardly from the interstices of part-length rods 22 is thereby deflected by the flat sides of the inverted deflector 34 into the volumes between the full-length fuel rods 20 to maintain a high density of liquid in that region. Again, the deflector 34 may be supported by a rod 36 depending from the upper tie plate, the deflector being centered with a spacer S, e.g., by clips or springs for easy removal through the upper tie plate. In FIGS. 10 and 11, there is illustrated a generally inverted conical deflector 40 supported by a structural support rod 42 from the upper tie plate and centered by the spacer similarly as in the preceding embodiment. It will be appreciated that because the steam vent volume is generally square in cross-sectional configuration, the conical deflector 40 extends upwardly into the corners of the steam vent volume as illustrated. That is, the conical-shaped surface of deflector 40 is extended upwardly from its full circular base (corresponding in diameter to the width of the steam vent volume) to fill in the corner areas of the steam vent volume V whereby the horizontally projected area of the deflector 40 is substantially coextensive with the rectilinear area of the steam vent path. This inverted conical deflector affords a substantial uniform distribution of liquid into the interstices of the full-length rods. As illustrated in FIGS. 12-14, an eight-sided pyramidal-shaped deflector 50 is provided. In this configuration, four of the flat areas 54 of the eight-sided pyramidal-shaped deflector can be disposed in opposition to the four corners, respectively, of the steam vent volume and extended upwardly beyond the base of the pyramid such that the entire cross-sectional area of the steam vent volume is occupied by portions of deflector 50. Thus, the horizontally projected area provided by deflector 50 is substantially coextensive with the horizontal rectilinear area of the steam vent path. Referring to FIG. 15, an inverted pyramidal or conical deflector 60 is provided with openings in registration with the part-length fuel rods. In this form, the inverted pyramid deflector is disposed at a location lower than the upper ends of the part-length fuel rods by receiving the part-length fuel rods through the respective registering openings. Consequently, the upwardly flowing liquid is deflected outwardly of the interstices of the part-length fuel rods and into the interstices of the full-length fuel rods prior to reaching the level of the upper ends of the part-length rods. Referring to FIG. 16, a cover or lid 70 may be disposed over the deflector plate 60 illustrated in FIG. 15. The cover is in a symmetrical form relative to the inverted deflector. For example, it may comprise an upstanding pyramid corresponding in shape to the inverted pyramidal deflector 60, thereby assisting in reducing the pressure drop across the deflector. Referring to FIG. 17, a swirl deflector is provided. In this configuration, swirl segments 70 are positioned just above one or more of the spacers and overlay the part-length fuel rods 22. A support rod 74 is also provided to mount and remove the swirl deflectors through the upper end of the fuel bundle. In all forms of deflector, the deflector is removable from the bundle or otherwise releasable to a position enabling access to and removal of the part-length rods from the bundle. While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
	summary
	abstract	A system for automatic production of radioisotopes includes an irradiation unit connectable to a cyclotron and having an electrolytic cell; a purification unit for purifying the radioisotope formed in the irradiation unit; two conduits for transferring an irradiated and electrodissolved target from the irradiation unit to the purification unit; and a central control unit for controlling both the operating units and the transfer means. The method for producing radioisotopes is such that the target carrier is not dissolved together with the irradiated target.
	abstract	Heat from an ex-vessel mass of core material is removed to cooler regions of a containment envelope via liquid and/or vapor phase transport. Various aspects provide for contacting the ex-vessel core material with a material having properties including melting point, boiling point, and condensation kinetics such that condensation of the material in cooler regions of the containment envelope is at least as fast as evaporation of the material due to heat absorption from the core material and associated species.
	claims	1. A steam generator level control system configured to prevent oscillation of a steam generator level at a nuclear power plant, the steam generator level control system comprising:a comparator configured to compare a steam generator level with a predetermined level-set value;a proportional integral control output unit configured to generate a proportional integral control value by using an output from the comparator;a high-level priority control signal generator configured to output a signal instructing to enter a high-level priority control mode if the steam generator level is equal to or greater than first criteria, and output a signal deactivating the high-level priority control mode if the steam generator level is equal to or less than second criteria after the steam generator level is equal to first criteria; anda high-level priority control signal receiver configured to control a control signal using the proportional integral control value of the proportional integral control output unit to be transmitted to a main feedwater pump and a feedwater control valve in a normal mode, obstruct a control signal using a value of the proportional integral control output unit in the high-level priority control mode, and control a predetermined output value to be transmitted to the main feedwater pump and the feedwater control valve,wherein the proportional integral control output unit comprises:a proportional integral controller configured to generate a proportional integral control value by using an output from the comparator; andan output reducer configured to control the proportional integral controller to generate, for a certain time, the proportional integral control value lower than the proportional integral control value in the normal mode if a high-level priority control mode is deactivated according to a signal from the high-level priority control signal generator,wherein the output reducer reduces the proportional integral control value until the steam generator level is reduced to a value equal to or less than a predetermined value after the high-level priority control mode is deactivated.
	claims	1. A method for developing a multi-focus primary collimator, said method comprising:creating a virtual system comprising a first source, a collimator block and a first detector;extending a first beam in the virtual system from the first source via the collimator block to the first detector;selecting a size of the first beam based on a configuration of the virtual system; anddisplaying the virtual system to a user via a display device. 2. A method in accordance with claim 1, wherein the virtual system further comprises a second detector, the method further comprising:extending a second beam in the virtual system from the first source via the collimator block to the second detector; andselecting a size of the second beam based on a configuration of the virtual system. 3. A method in accordance with claim 1, wherein the virtual system further comprises a second source, the method further comprising establishing a width of the first beam based on a distance between the first source and the second source. 4. A method in accordance with claim 1, wherein the virtual system further comprises a second source adjacent to the first source, the method further comprising establishing a width of the first beam based on a distance between the first source and the second source. 5. A method in accordance with claim 1, wherein the virtual system further comprises a second source, the method further comprising establishing a width of the first beam based on a distance between the first source and the second source and based on a number of detectors in the virtual system including the first detector. 6. A method in accordance with claim 1, wherein the virtual system further comprises a second source and a second detector, the method further comprising establishing a width of the first beam based on a distance between the first source and the second source and based on a number of detectors in the virtual system including the first detector and the second detector, wherein the first detector receives the first beam and the second detector receives a second beam from the first source. 7. A method in accordance with claim 1, wherein the virtual system further comprises a gantry, and wherein the collimator block includes a primary collimator placed between the first source and an opening of the gantry. 8. A method in accordance with claim 1 further comprising developing a virtual collimator channel, within the collimator block, at a passage of the first beam via the collimator block. 9. A method in accordance with claim 1, wherein the virtual system further comprises a second detector, the method further comprising:extending a second beam from the first source via the collimator block to the second detector:selecting a size of the second beam based on a configuration of the virtual system; anddeveloping a first virtual channel, within the collimator block, at a plurality of positions of a passage of the first beam via the collimator block; anddeveloping a second virtual channel, within the collimator block, at a plurality of positions of a passage of the second beam via the collimator block. 10. A processor configured to:create a virtual system comprising a first source, a collimator block and a first detector;extend a first beam from the first source via the collimator block to the first detector;select a size of the first beam based on a configuration of the virtual system; andpresent the virtual system to a user on a display device. 11. A processor in accordance with claim 10, wherein the virtual system further comprises a second detector, the processor further configured to:extend a second beam from the first source via the collimator block to the second detector; andselect a size of the second beam based on a configuration of the virtual system. 12. A processor in accordance with claim 10, wherein the virtual system further comprises a second source, the processor further configured to establish a width of the first beam based on a distance between the first source and the second source. 13. A processor in accordance with claim 10, wherein the virtual system further comprises a second source adjacent the first source, the processor further configured to establish a width of the first beam based on a distance between the first source and a second source. 14. A processor in accordance with claim 10, wherein the virtual system further comprises a second source, the processor further configured to establish a width of the first beam based on a distance between the first source and the second source and based on a number of detectors in the virtual system including the first detector. 15. A processor in accordance with claim 10, wherein the virtual system further comprises a second source and a second detector, the processor further configured to establish a width of the first beam based on a distance between the first source and the second source and based on a number of detectors in the virtual system including the first detector and the second detector, wherein the first detector receives the first beam and the second detector receives a second beam from the first source. 16. An imaging system comprising:at least one actual source configured to generate energy;at least one actual detector configured to detect a portion of the energy; anda processor configured to:create a virtual system embodying a relative placement of the at least one actual source and the at least one actual detector, the virtual system comprising a first source, a collimator block and a first detector;extend a first beam from the first source via the collimator block to the first detector;select a size of the first beam based on a configuration of the virtual system; andpresent the virtual system to a user on a display device. 17. An imaging system in accordance with claim 16, wherein the virtual system further comprises a second detector and wherein said processor is further configured to:extend a second beam from the first source via the collimator block to the second detector; andselect a size of the second beam based on a configuration of the virtual system. 18. An imaging system in accordance with claim 17 further comprising an actual collimator block, wherein the size of the first beam is used to develop a first collimator channel in the actual collimator block and the size of the second beam is used to develop a second collimator channel in the actual collimator block. 19. An imaging system in accordance with claim 16, wherein the virtual system further comprises a second source and wherein said processor is further configured to establish a width of the first beam based on a distance between the first source and the second source. 20. An imaging system in accordance with claim 16, wherein the virtual system further comprises a second source adjacent to the first source and wherein said processor is further configured to establish a width of the first beam based on a distance between the first source and the second source. 21. An imaging system in accordance with claim 16, wherein the virtual system further comprises a second source and wherein said processor is further configured to establish a width of the first beam based on a distance between the first source and the second source and based on a number of detectors in the virtual system including the first detector. 22. An imaging system in accordance with claim 16 further comprising an actual collimator block, wherein the size of the first beam is used to develop a first collimator channel in the actual collimator block.
055132316	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of a cask 10 for transportation and short-term storage of spent nuclear fuel is shown in FIG. 1. The cask 10 includes a body 12 constructed from a tubular structural shell 14 having an upper shell portion 16 and a lower shell portion 18. The lower shell portion 18 is sealed by a bottom closure plate 20 that has a central access aperture 22 that is sealed with an access cover plate 24. The upper shell portion 16 is sealed with a top closure plate 26. The exterior of the structural shell 14 is shielded with a neutron absorbing shield jacket 28. Two diametrically opposed upper trunnions 30 (only one shown) are secured within upper trunnion mounting sleeves 32 to the exterior of the upper shell portion 16. Two lower trunnions 34 are secured in diametric opposition to the lower shell portion 18 within lower trunnion mounting sleeves 36. As used herein throughout, "bottom" and "lower" refer to the end of the cask 10 and its components closest in proximity to the bottom closure plate 20. while the words "top" and "upper" refer to the opposite end proximate the top closure plate 26. A dry storage canister 38 for spent nuclear fuel is shown installed within the interior cavity 40 of the cask 10. The construction of the dry storage canister 38 is fully described in a U.S. Pat. No. 5,438,597, the disclosure of which is hereby expressly incorporated by reference. A plurality of lugs 42 are secured to the structural shell 14 and to the annular ends of the shield jacket 28 about the circumference of the cask 10, on both the lower and upper (not shown) ends of the shield jacket 28. The purpose of the lugs 42 is to enable mating of the cask 10 with impact limiters during transport. Impact limiters and transportation skids suitable for use in transporting the cask 10 are fully disclosed in a U.S. Pat. No. 5,394,449, the disclosure of which is hereby expressly incorporated by reference. Referring now to FIG. 2, the construction of the body 12 shall be described. The body 12 has an overall cylindrical configuration and includes the structural shell 14. The structural shell 14 has a tubular configuration and defines a central longitudinal axis 44 that is aligned with the central longitudinal axes of the other annular components of the body 12, as shall be described. The lower shell portion 18 of the structural shell 14 also has a tubular configuration, defining a circumferential bottom edge 46 and a circumferential top edge 48. The length of the lower shell portion 18 is approximately two-thirds the length of the structural shell 14. The upper shell portion 16 extends the remaining one-third of the length, and defines a circumferential lower edge 50 and a circumferential top edge 52. The upper edge 48 of the lower shell portion 18 abuts and is welded to the lower edge 50 of the upper shell portion 16, using a full penetration weld around the entire circumference of the structural shell 14. The upper shell portion 16 and lower shell portion 18 each have a central axis that is aligned with the longitudinal axis 44, and cooperatively define a right cylinder. The lower shell portion 18 is formed from a rigid material, preferably a corrosion resistant metal, and most preferably a stainless steel, such as ASME SA-240 type 304 austentitic stainless steel. However, the upper shell portion 16 is preferably formed from a material having a higher load beating strength, also preferably a stainless steel, such as ASME SA-240 type XM-19 high alloy stainless steel. Type XM 19 stainless steel is also austentitic, but has approximately twice the load bearing strength of type 304. As shown in FIG. 1, the upper trunnions 30 are secured to the upper shell portion 16. The upper trunnions 30 are intended to be used for hoisting and lifting the cask 10, both when empty and when loaded with a full canister 38. Thus, the upper trunnions 30 in use transmit significant shear and tensile loads to the upper shell portion 16. The lower shell portion 18 carries the lower trunnions 34, which are used to upright and stabilize the cask 10 during transport, as shall be described subsequently, and thus are subjected to lower loading. Because type XM-19 stainless steel is more costly than type 304 stainless steel, the cost of manufacture is reduced by utilizing the XM-19 for the load beating portions of the cask 10. Both portions of the structural shell 14 can be formed and welded from rolled plate. Referring to FIG. 2, coaxially installed within the structural shell 14 is an inner shell 54, which also may be formed film type 304 stainless steel or other suitable corrosion resistant structural materials. The inner shell 54 is slightly smaller in external diameter than the interior of the structural shell 14, and thus defines an annular space therebetween. This annular space is filled with a gamma radiation absorbing material 56, such as ASTM B-29 chemical lead. The steel contained in the structural shell 14 and the inner shell 54, as well as the bottom closure plate 20 and top closure plate 26, also serve to absorb gamma radiation. The shield jacket 28 has a tubular configuration and is installed over and surrounds the majority of the length of the structural shell 14. The shield jacket 28 is formed from a tubular outer skin 58. The internal diameter of the outer skin 58 is greater than the external diameter of the shell 14, thus defining an annular space that is filled with a neutron radiation absorbing shield material 60. One suitable neutron radiation absorbing shield material 60 is a hydrogenous solid neutron absorbing material, such as a cementious castable neutron absorbing material. The upper and lower ends of the shield jacket 28 are closed by upper and lower annular support rings 62 and 63, respectively, welded to the exterior of the structural shell 14 and the edges of the outer skin 58. The lower annular support right 63 includes stainless steel rupture discs which prevent over pressurization of the shield jacket 28. A pair of elongate rails 64 are secured by welding or other means to the interior of the inner shell 54 of the body 12. The rails 64 are oriented parallel to the central longitudinal axis 44 of the cask 10, and extend the length of the inner shell 54. Each rail 64, also shown in FIG. 6, is formed from a strip of flat sheet. The rails 64 are spaced radially apart from each other within the same radial quadrant of the inner shell 54. The rails 64 are positioned on the side of the cask body 12 that rests on the trailer or other support surface when the cask 10 is laid down horizontally Each rail 64 is preferably formed from a material that is harder than the material used to construct the inner shell 54, such as a hardened stainless steel, which provides a non-gouging, low-friction surface for the canister 38 to slide on during installation or removal of the canister 38 from the cask 10. One suitable material is nitronic 60, cold reduced sheet, ASTM A-240, grade UNS, 521800, RC29.35 stainless steel. The bottom edge 46 of the lower shell portion 18 and the bottom edge of the inner shell 54 are each welded to the bottom closure plate 20, thereby sealing the bottom end of the body 12, as shall be described in more detail subsequently. The top edge 52 of the upper shell portion 16 and the top edge of the inner shell 54 are each welded to an annular sealing ring 66. The top closure plate 26 can be secured to the annular sealing ring 66 to selectively close the top end of the body 12. Reference will now be had to FIGS. 2 and 3A to describe the configuration of the annular sealing ring 66. The sealing ring 66 has a main body portion having an essentially rectangular cross section. An annular lower flange 70 extends downwardly from the lower surface of the body portion 68 adjacent the inner edge of the ring 66. The lower flange 70 has an internal diameter substantially equal to the internal diameter of the internal shell 54. The top edge 52 of the upper shell portion 16 is welded to the main body portion 68 of the annular sealing ring 66, while the lower edge of the lower flange 70 is welded to the top edge of the inner shell 54. Both welds are full penetration welds extending around the full circumference of the annular sealing ring 66. The top surface of the body portion 68 defines an annular abutment surface 74. An annular upper flange 76 projects upwardly from the abutment surface 74 along the outer perimeter of the annular sealing ring 66. A hardened sealing surface is formed on the abutment surface 74 by an annular hardened metal inlay 78. The inlay 78 is preferably formed by weld overlay of a hard metal onto the base metal of the annular sealing ring 66. The annular sealing ring 66 is preferably formed from a machined ring forging of type 304 stainless steel. The inlay 78 is preferably formed of inconel alloy. The inlay 78 wraps the inner upper corner of the body portion 68 of the annular sealing ring 66, so that it provides a hard polished surface on both the inner portion of the abutment surface 74 and the upper portion of the internal diameter of the body portion 68. The hard surface provided by the inlay 78 is highly resistant to permanent deformation upon impact of the joint area of the cask 10. Referring still to FIGS. 2 and 3A, the top closure plate 26 is configured as a solid disk. The top plate 26 has an annular recess formed about its perimeter in its bottom side that defines an annular sealing surface 80. The annular sealing surface 80 corresponds in dimension substantially to the abutment surface 74 of the annular sealing ting 66. As shown in FIG. 3 A, the top closure plate 26 is installed on the body 12 by sliding the top closure plate 26 within the annular upper flange 76 of the annular sealing ting 66. When so installed, the sealing surface 80 of the top closure plate 26 abuts the abutment surface 74 of the annular sealing ting 76. A non-recessed center portion 82 of the bottom side of the top closure plate 26 is received within the inside diameter of the body portion 68 of the annular sealing ring 66. The inlay 78 provides the sealing surface for the annular sealing ring 66. Two annular grooves 84 are formed in the portion of the sealing surface 80 of the top closure plate 26 that overlies the inlay 78. As shown in FIG. 3A, a seal 86 is received within each of the grooves 84. The seals may be either deformable metal seals, or elastomefic seals, e.g., O-rings, or alternately configured elastomeric seals. The seals 86 are deformed between the top closure plate 26 and the annular sealing ring 66, and retained within the grooves 84. Referring to FIG. 3B, each of the grooves 84 defines a half-dovetail cross-section, having a bottom surface 88, a first orthogonal side surface 90, and a second, inwardly angled side surface 92. The half-dovetail configuration of the grooves 84 ensures that the seals 86 are retained within the grooves 84 when the body 12 is positioned either horizontally or vertically and the top closure plate 26 is removed. The weld between the annular sealing ring 68 and the inner shell 54 is airtight. The weld between the annual sealing ring 68 and the upper shell portion 16 is also believed to be airtight, but is not tested for that characteristic. Likewise, the seal joint formed by the sealing surface 80, abutment surface 74, and seal 86 is also airtight. The top closure plate 26 is selectively secured to the annular sealing ring 66 by installing a plurality of bolts 94 through recessed apertures 96 formed at evenly-spaced intervals about the perimeter of the top closure plate 26 into correspondingly located threaded passages 98 formed in the abutment surface 74 of the annular sealing ring 66. Drain holes (not shown) are provided at the base of each threaded passage 98. Referring to FIG. 6, two monitoring ports 100 are formed in the top closure plate and are selectively sealed by plugs 102. Attention is now directed to FIGS. 2 and 4 to describe the airtight joints formed between the bottom closure plate 20 and the structural shell 14 and inner shell 54. The bottom shell 20 is also configured as a solid disk. An annular flange 104 projects upwardly from the top (i.e., inner) surface of the bottom closure plate 20, at a location spaced radially inwardly from the outer perimeter of the top closure plate 20. When the bottom closure plate 20 is placed over the bottom end of the body 12, an upper edge of the flange 104 abuts the lower edge of the inner shell 54. The upper edge of the flange 104 is welded to the lower edge of the inner shell 54. The bottom edge 46 of the lower shell portion 18 is welded to the bottom closure plate 20. Both welds are full penetration welds formed about the full circumference of the bottom closure plate 20, and the weld between the inner shell 54 and the flange 104 is airtight. The weld between the lower shell portion 18 and the flange 104 is also believed to be airtight, but is not tested for that characteristic. A drain port 106 is formed through the bottom closure plate 20, from the top (inner) surface of the plate to the plate's outer circumference, and is sealed with a threaded bolt 108 capped by a threaded plug 110. The threaded bolt 108 and threaded plug 110 each include a seal (not shown) that is leak tight. The port 106 permits drainage of liquids from the interior cavity 40 of the cask 10. The drain port 106 may be located at any orientation on the bottom of the cask. Referring to FIGS. 2 and 5A, the central access aperture 22 is formed centrally through the bottom closure plate 20. An annular recess 112 is formed in the bottom (i.e., outer) side of the bottom closure plate 20, effectively enlarging the diameter of the bottom portion of the central access aperture 22. The recess 112 defines an annular abutment surface 114. A hardened inlay 116, which may be formed by weld overlay of a hard metal, such as inconel, is formed angularly around the innermost portion of the abutment surface 114 adjoining the access aperture 22. The inlay 116 is polished to define a sealing surface. The access cover plate 24 is configured as a solid disk having an outer diameter that is sized to be received within the recess 112. An annular recess is formed in the top (i.e., inner) side of the access cover plate 24 about the plate's perimeter to define a sealing surface 118. A non-recessed center portion 120 is bordered by the sealing surface 118. When the access cover plate 24 is assembled to the bottom closure plate 20, the access cover plate 24 is received within the recess 112 of the bottom closure plate 20, with the center portion 120 of the access plate 24 being received within the central access aperture 22. The sealing surface 118 overlies the inlay 116 in this installed configuration. Referring to FIGS. 5A and 5B, two half-dovetailed annular grooves 122, configured similarly to the previously described grooves 84 in the top closure plate 26, are formed in the sealing surface 118. Again, seals (not shown) are received within the grooves 122 and are compressed between the sealing surface 118 and the inlay 116 to form an airtight seal between the ram closure plate 24 and the bottom closure plate 20. The ram closure plate 24 is retained in place by a plurality of bolts 124 inserted through recessed apertures 126 formed at spaced intervals about the periphery of the access cover plate 24 and received within threaded passages 128 formed at corresponding locations in the abutment surface 114 of the bottom closure plate 20. The bottom closure plate 20 is preferably formed from a machine forging, such as a type 304 stainless steel forging. The ram closure plate is preferably formed from a higher strength material, such as type XM-19 stainless steel. Referring to FIG. 6, the construction of the shield jacket 28 will now be described in greater detail. As noted previously, the outer skin 58 of the shield jacket 28 is larger than the external diameter of the upper shell portion 16 and lower shell portion 18. The annular space created therebetween is filled with neutron radiation absorbing shield material 60. Neutron radiation shielding material 60 is not a strong load bearing material, and thus a plurality of elongate reinforcing members 130 are embedded within the shield material 60. The elongate reinforcing members 130 are oriented so as to be parallel to the central axis 44 of the cask body 12. Each reinforcing member 130, which are also illustrated in FIGS. 8 and 9, is bent centrally along its length on two fold lines, such that each member 130 defines a flattened V-shaped cross section. Each member 130 thus has an elongate center portion 132 and first and second elongate leg portions 134 that project angularly outwardly from the center portion 132. The center portion 132 of each member 130 is welded to the interior of the outer skin 58 of the shield jacket 28. The projecting edges of each of the two leg portions 134 contacts and is welded to the outside of the structural shell 14. This gives a "corrugated" reinforcing effect to the structure of the shield jacket 28. The reinforcing members 130 transfer heat from the structural shell 14 through the shield jacket 28 to the exterior of the cask 10 to remove the decay heat of spent fuel contained within the cask 10, and also provide an integral structural system for supporting the cask during transport. Reference is now had to FIGS. 1, 7, and 8 to describe an additional feature of the cask 10. The cask 10 includes a tie-down key way structure 136. The key way structure 136 serves as an anchor point for a tie-down that secures the cask 10 to a transport skid for secure transportation. The key way structure 136 defines an elongate arcuate opening formed through the shield jacket 28 approximately mid-length of the body 12. The key way structure 136 has a radially oriented length and an axially oriented width, and is formed from four frame members that are welded directly to the structural shell 14. Referring now to FIGS. 7 and 8, the long sides of the key way structure 136 are formed by arcuate bearing blocks 138 that are mounted arcuately in spaced-apart disposition on the lower shell portion 18. The perimeter frame of the key way structure 136 is completed by two longitudinally oriented tie-bar members 140 welded across the opposing ends of the bearing blocks 138. Each of the bearing blocks 138 and tie-bars 140 is welded to the lower shell portion 18, and cooperatively define a rectangular frame. A recess 142 is formed in the outer surface of each of the bearing blocks 138 and tie-bars 140 about the inner perimeter of the frame defined thereby. The perimeter frame defined by the bearing blocks 138 and tie-bars 140 are further reinforced by an arcuate pad plate 144 that fits over the beating blocks 138 and tie-bars 140. The pad plate 144 is disposed within the interior of the shield jacket 28 and is welded directly to the lower shell portion 18, as well as to the bearing blocks 138 and tie bars 140. The outer skin 58 of the shield jacket 28 is also welded to the tie bars 140 and bearing blocks 138. The pad plate 144, tie bars 140, and bearing blocks 138 are preferably formed from a high-strength metal, such as type XM-19 stainless, due to the stress imposed on them during use. Because it is desired that the key way structure 136 be sacrificed rather than the integrity of the structural shell 14 in the event of excessive loads applied to the key way structure 136, the welds between the key way structure 136 and the lower shell portion 18 and outer skin 58 of the shield jacket 28 are relatively small. This ensures that the key way structure 136 will give way prior to breakage of the structural shell 14 in the event of extreme loads on the key way structure 136. The construction of the upper trunnions 30 and lower trunnions 34 will now be described with reference to FIGS. 9 and 10, respectively. The upper trunnions 30 and lower trunnions 34 are similarly constructed except as noted. Thus, only the upper trunnion 30 will be described with it being understood that the same description applies to the lower trunnion 34. The upper trunnion 30 has a cylindrical body 146. An annular flange 148 is formed about the midsection of the body 146. A recess 150 is formed in one of the circular faces 152 of the body 146, and extends fully into the interior of the body 146 to define a cavity 154. The body 146 thus has a hollow configuration. The portion of the trunnion body 146 between the flange 148 and the first face 152 defines a cylindrical base 156. The interior cavity 154 is filled with neutron radiation absorbing shield material 60. The neutron shield material 60 is capped and retained by a circular back plate 158 that is received within the recess 150 and welded in position. The presence of the neutron shield material 60 reduces streaming of neutrons through the upper trunnions 30. A cylindrical beating projection 160 projects from the second circular face 162 of the trunnion body 146. An annular flange 164 is formed about the end of the bearing projection 160. The bearing projection 160, flange 164, and second circular face 162 cooperatively define a beating groove that can be grasped by a correspondingly contoured hook for transport of the cask 10. A plurality of apertures 166 are formed through the flange 48 at spaced intervals about the perimeter of the upper trunnion 30, for purposes of securement to the cask 10 by bolts 168. The lower trunnions 34 are configured similarly to the upper trunnions 30, except that no cylindrical beating projection 160 projects from the trunnion body 146. Additionally, the interior cavity 154 is not filled with a neutron shield material, and back plate 158 is also not included. The upper trunnion 30 can be selectively and releasably secured to the cask body 12 by engagement with the upper trunnion mounting sleeve 32. The upper trunnion mounting sleeve 32 consists of a tubular sleeve that projects through and is welded to the upper shell portion 16. A circular aperture 170 is formed through the upper shell portion 16 at the desired location for the upper trunnion mounting sleeve 32. A similarly oriented aperture is formed through the outer skin 58 of the shield jacket 28. The upper trunnion mounting sleeve 32 is installed through the shield jacket 28 and the upper shell portion 16 such that the central axis (not shown) of the upper trunnion mounting sleeve 32 is oriented radially relative to the longitudinal axis 44 of the cask body 12. The upper trunnion mounting sleeve 32 is welded fully about its perimeter to the upper shell portion 16. Additionally, a weld is formed between the outer skin 58 of the shield jacket 28 and the upper trunnion mounting sleeve 30. A circular trunnion filler plate 171 is installed within the upper trunnion mounting sleeve 32, and positioned within the radially inward end of the trunnion mounting sleeve 30 so as to be in line with the arc of the upper shell portion 16. The trunnion filler plate 170 is welded to the interior of the upper trunnion mounting sleeve 32 to seal the radially interior end of the upper trunnion mounting sleeve 32. An annular recess 172 is formed about the entry to the upper trunnion mounting sleeve 32. To secure the upper trunnion 30 in position on the cask 10, the circular base 156 of the upper trunnion 30 is slidably received within the interior passage 174 defined by the upper trunnion mounting sleeve 32, and the flange 148 of the upper trunnion 30 is received within the recess 172. The dimensional tolerances of the interior passage 174 of the upper trunnion mounting sleeve 30 and the recess 172, as well as the base 156 and flange 148 of the upper trunnion 30, are closely controlled such that a very close slip fit is formed between the upper trunnion 30 and the upper trunnion mounting sleeve 32. This ensures that the upper trunnion 30 cannot become cocked within the upper trunnion mounting sleeve 32. The bolts 168 are installed through the apertures 166 and the flange 148 of the upper trunnion 30 and into correspondingly arranged threaded passages 176 formed into the recess 172 of the upper trunnion mounting sleeve 32. Because of this two-piece mounting of the upper trunnion 30, utilizing the separate upper trunnion 30 and upper trunnion mounting sleeve 32, the upper trunnion 30 can be removed as desired when hoisting of the cask 10 is not required. Additionally, because the upper trunnion mounting sleeve 32 receives and captures the upper trunnion 30, the bolts 168 are substantially isolated from shear and tensile loads, which instead are transmitted from the upper trunnion 30 to the upper trunnion mounting sleeve 32 and then to the structural shell 14. This construction helps to ensure that the upper trunnions 30 are not tom off of the structural shell 14 when the upper trunnions 30 are grasped to hoist the weight of the cask 10 and the contents therein. The upper trunnion mounting sleeve 32 and upper trunnion 30 are preferably formed from a high strength metal, such as type XM-19 stainless steel. The trunnion backing plate 158 can be formed from type 304 stainless steel or other suitable metals. Referring to FIG. 10, the lower trunnion mounting sleeve 36 is identically constructed and secured to the lower shell portion 18, as was the upper trunnion sleeve 32 constructed and secured to the upper shell portion 16, except as noted herein. Because the stresses imposed on the lower trunnions 34 are not as great as those imposed on the upper trunnions 30, a recess 172 is not formed in the outer face of the lower trunnion mounting sleeve 36 to receive the flange 148 of the lower trunnion 34. Instead, the axial length of the lower trunnion mounting sleeve 36 is correspondingly reduced, and the flange 148 of the lower trunnion 34 abuts the annular exterior face 178 of the lower trunnion mounting sleeve 36. Referring now to FIG. 11 A, oecen when the cask 10 has been loaded with a canister 38, the cask 10 will be temporarily stationary on-site. During such times, it is not required to mount the upper trunnions 30 and lower trunnions 34 on the cask 10. In such instances, it is desired to further reduce neutron streaming past the trunnions 30 and gamma streaming past trunnions 34 by removing the trunnions 30 and 34, and capping the upper trunnion mounting sleeves 32 with trunnion shields 180 trunnion mounting sleeves 36 with trunnion shields 181. Trunnion shields 180 are metal disks that are filled with neutron shield material 60 (not shown) and bolted to the upper trunnion mounting sleeves 32. Trunnion shields 180 are solid metal disks bolted to the upper trunnion mounting sleeves. Additionally, when not in transport, the key way structure 136 is not being utilized. At such times, it is desirable to mount a key way shield 182 (also shown in FIG. 1) to cover the key way structure 136. The key way shield 182 is again filled with a neutron shield material 60 and is secured by bolting a top plate 184 to the frame of the key way structure 136. This again is to reduce neutron streaming through the key way structure 136. Finally, during unloading of the canister 38 from the cask 10, it is necessary to remove the access cover plate 24 from the bottom closure plate 20, as shall be described briefly below. During such times when the access cover plate 24 is removed from the cask 10 and it is not actually necessary to insert a ram, as shall be described, through the central access aperture, an access aperture shield assembly 186 is secured centrally to the bottom closure plate 20 to cover the access aperture 22. Referring to FIG. 11B, the access aperture shield assembly 186 consists of an annular first shield member 188 that is formed from two annular plates 190 that are secured together by an annular ring 192. An aperture 194 is formed centrally through the plates 190, and an internal ring 196 borders this aperture 194. The interior of the first shield member 188 is filled with a neutron absorbing shield material 60. A second similarly constructed shield member 198 is also utilized. Shield member 198 is also formed as a disk, but is a smaller diameter than shield member 188, and includes no central aperture. It also is filled with neutron absorbing shield material 60. Shield member 198 is supported by a plurality of hangers 200, extending outwardly from the first shield member 188 around aperture 194 in the shield member 188. When both the shield member 198 and shield member 188 are utilized, the complete area of the central access aperture 22 is shielded. Referring to FIGS. 12, 13 and 14, in another aspect, the present invention relates to a skid for supporting and protecting the transportation cask for spent nuclear fuel during transportation. FIG. 12 illustrates a conventional trailer 226 that includes a transportation cask enclosed by skid 220 formed in accordance with the present invention and a pair of impact limiters 222 formed in accordance with the invention described in the application entitled Impact Limiter For Spent Nuclear Fuel Transportation Cask. In FIG. 12, the transportation cask is not visible, as it is completely encased by skid 220 and impact limiters 222. Skid 220 is further enclosed by a curtain of expanded metal 224, which further obscures skid 220 and the transportation cask. The curtain of expanded metal 224 is provided around skid 220 in order to shield skid 220 and the transportation cask from sunlight. In FIG. 12, the longitudinal axis of the transportation cask is parallel to the length of trailer 226. Impact limiters 222 are positioned on opposite ends of the generally cylindrical transportation cask. Skid 220 supports the transportation cask along its length between impact limiters 222, as described below in more detail. Referring primarily to FIGS. 13 and 14, transportation skid 220 comprises a lower supporting member 290 and an upper retaining member 292. Lower supporting member 290 carries the vertical and lateral cask loads and includes a plurality of parallel spaced-apart plates 294 lying perpendicular to the longitudinal axis of the transportation cask. Plates 294 include an outer peripheral portion that is substantially square and in use rests on the bed of a transportation trailer. The inner periphery of plates 294 includes a trough which in the illustrated embodiment is semicircular and mates with a portion of the exterior surface of the transportation cask. At the bottom of the trough in supporting member 290 is a saddle 291 that comprises a plate extending lengthwise along the bottom of the trough and widthwise up the sides of the trough. In the illustrated embodiment, saddle 291 occupies approximately one-third of the bottom radius of the trough. At the bottom of the trough centrally located along the length of saddle 291 is an upward protruding rectangular block 296 that serves as a shear key for mating with tie-down keyway structure (136 in FIG. 1) on the transportation cask. Block 296 cooperates with the transportation cask in order to provide an independent means for carrying axial shear loads for the cask. Spaced-apart plates 294 of lower supporting member 290 are connected by a plurality of longitudinal fins 201 running parallel to the longitudinal axis of the transportation cask. In the illustrated embodiment, plates 294 are made from one-inch steel plates and fins 201 comprised of one-half-inch thick steel plates. Plates 294 provide support for the transportation cask for downward, vertical and transverse loads from the cask. Upper retaining member 292 carries vertical upward loads for the cask and includes a plurality of spaced-apart plates 298 lying perpendicular to the longitudinal axis of the transportation cask. In the illustrated embodiment, the inner periphery of plates 298 includes an inverted semi-circular trough that is a mirror image of the trough in supporting member 290. The outer periphery of plates 298 is substantially concentric with its inner periphery. Upper retaining member 292 also includes a plurality of parallel longitudinal fins 202 that are positioned parallel to the longitudinal axis of the transportation cask. In the illustrated embodiment, plates 298 and fins 202 are made from metal, such as aluminum. Upper retaining member 292 and lower supporting member 290 mate with each other to define a cylindrical cavity which completely encases the neutron shielding material (60 in FIG. 2). As described above, the neutron radiation Shielding material is not a strong load-bearing material, and accordingly, a plurality of elongate reinforcing members (130 in FIG. 6) are embedded within the shield material. The elongate reinforcing members are oriented so as to be parallel to the central axis of the cask body. The radial spacing between fins 201 and fins 202 is such that when the transportation cask is mated with rectangular block 296, the center portions 132 of the elongate reinforcing members 130 in the neutron radiation shielding material are aligned and rest along longitudinal fins 201 and 202. Accordingly, the neutron shielding material does not carry the load of the cask, but rather the elongate reinforcing members resting on the longitudinal fins serves to carry the load of the cask. Utilization of the cask 10 shall now be briefly described. When it is desired to install a canister 38 into the cask 10, the access cover plate 24 is secured to the bottom closure plate 20, while the top closure plate 26 is removed from the cask body 12. The canister 38 is installed into the interior cavity 40 of the cask body 12. These operations are performed inside pools or otherwise in accordance with industry practice. Transport of the open cask during this time is made by grasping the upper trunnions 30 to hoist the cask 10. After water is drained from the interior of the cask 10, and the cask 10 is dried in accordance with standard industry practice, the top closure plate 26 is secured to the cask body 12. The cask 10 is now hoisted by again hooking the upper trunnions 30 to move the cask 10 to a transport trailer. While being hoisted, the cask 10 is oriented vertically with the weight of the cask being supported by the upper trunnions 30. The cask 10 is then repositioned horizontally on a trailer, during which operation the lower trunnions 34 are utilized to stabilize and reposition the cask 10. The cask 10 can then be transported to the site where the canister 38 is to be installed in a horizontal storage module or other storage module. Once the cask 10 has arrived at the storage site, the top closure plate 26 is removed and the top end of the open cask body 12 is docked with the intended storage module. The access cover plate 24 can then be removed, and replaced with the access aperture shield assembly 186 to reduce neutron streaming. When it is time to transfer the canister 38 from the cask 10 to the storage module, the second shield member 198 is removed from the access aperture shield assembly 186. A ram can then be inserted through the remaining shield member 198 and the access aperture 22 into the interior cavity 40 of the cask body 12. The ram then pushes the canister 38, which slides on the rails 64 as it moves through the open end of the cask body 12, defined by the annular sealing ring 66. The canister 38 thus moves into the storage module. Once transfer of the canister 38 is completed, the cask 10 can be reassemble and reutilized. For transportation, the reverse operations to those described above are performed to retrieve the canister into the cask. The cask in then lifted from the trailer and placed on a suitable transportation skid, such as described above, with a shear key which engages the keyway structure 136. The trunnions 30 and 34 are removed and trunnion shields 180 and 181 are installed. While the present invention has been described above in terms of a preferred embodiment, it should be readily apparent to those of ordinary skill in the art that various alterations, modifications and substitutions may be made within the scope of the present invention. For example, materials other than those described can be utilized to form the components of the cask 10, provided that they meet the parameters set forth herein. It is thus intended that the scope of letters patent granted hereon be limited only by the definitions contained in the appended claims.
043839444	claims	1. A method for producing a molded body containing radioactive wastes, in which the wastes are mixed with molten glass or are melted together with glass formers to form a melt, and the melt is converted into glass granules or glass powder comprising: (a) mixing the glass granules or glass powder with a powder of a metal selected from the group consisting of lead, iron, silver, cobalt, nickel, tin and mixtures thereof, wherein the glass-to-metal ratio is selected so that the glass-to-metal ratio in the molded body is 20:1 to 1:6, by volume, and, (b) condensing the mixture resulting from step (a) by subjecting the mixture to pressure of 25 Newtons/mm.sup.2 to 500 Newtons/mm.sup.2 to form a molded body in which the glass granules or glass powder are discontinuously embedded without contacting each other in the metal which forms a continuous metal matrix phase. 2. The method of claim 1, further comprising sintering the condensed mixture at a temperatue below the melting point of the lowest melting metal present in the mixture, in order to increase the strength and density of the molded body. 3. The method of claim 1 or 2 wherein the step of condensing the mixture is done at room temperature. 4. The method of claim 1 or 2, wherein the glass granules or glass powder and metal powder which are mixed are sedimentatively matched. 5. The method of claim 1 or 2 wherein said radioactive wastes are high activity radioactive wastes. 6. The method of claim 1 or 2 wherein said radioactive wastes are medium activity radioactive wastes. 7. The method of claim 1 or 2 wherein said radioactive wastes are derived from actinide concentrates or from ashes and residues of combustion of organic radioactive wastes. 8. The method according to claim 1 or 2 wherein the particle size of said glass granules or glass powder is about 1 .mu.m to about 2 mm. 9. The method of claim 1 or 2 wherein said glass granules or glass powder have particles in the form of spheres or cylindrical fibers, said particles being statistically oriented in the molded body. 10. The method of claim 1 or 2 wherein the ratio of the average size of the particles of said glass granules or glass powder to the average size of the particles of said metal powder is approximately equal to ##EQU3## where .rho. glass is the density of the glass and .rho. metal is the density of the metal. 11. The method of claim 1, wherein the metal powder is lead. 12. The method of claim 1, wherein the metal powder is silver. 13. The method of claim 1, wherein the metal powder is a mixture of metal powders. 14. The method of claim 1, wherein the metal powder is selected from the group consisting of lead, silver, cobalt, tin and mixtures thereof.
055639259	description	DETAILED DESCRIPTION The invention is described below with primary reference to a system for delivering X-ray radiation to a field of a patient, and for delimiting the field using at least one movable plate in the beam path from a radiation source. This is by way of example only. The invention may be used to adjust the delivery of any type of energy, for example, electrons (instead of X-rays), to any type of object (not just a human patient), provided the amount of energy delivered to the field can be sensed or estimated. FIG. 1 shows a radiation treatment device 2 of common design, in which plates 4 and a control unit in a housing 9 and a treatment unit 100 constructed in accordance with the principles of the invention are used. The radiation treatment device 2 comprises a gantry 6 which can be swiveled around a horizontal axis of rotation 8 in the course of a therapeutic treatment. Plates 4 are fastened to a projection of gantry 6. To generate the high-powered radiation required for the therapy, a linear accelerator is located in gantry 6. The axis of the radiation bundle emitted from the linear accelerator and gantry 6 is designated by 10. Electron, photon, or any other detectable radiation can be used for the therapy. During the treatment the radiation beam is trained on a zone 12 of an object 13, for example, a patient who is to be treated, and who lies at the isocenter of the gantry rotation. The rotational axis 8 of gantry 6, the rotational axis 14 of a treatment table 16, and the beam axis 10 all preferably intersect in the isocenter. The construction of such a radiation treatment device is described in general in a brochure "Digital Systems for Radiation Oncology", Siemens Medical Laboratories, Inc. A91004-M2630-B358-01-4A00, September 1991. The area of the patient that is irradiated is known as the field. As is well known, the plates 4 are substantially impervious to the emitted radiation. They are mounted between the radiation source and the patient in order to delimit the field. Areas of the body, for example, healthy tissue, are therefore subjected to as little radiation as possible, and preferably to none at all. In the preferred embodiment of the invention, at least one of the plates is movable so that the distribution of radiation over the field need not be uniform (one region can be given a higher dose than another); furthermore the gantry can preferably be rotated so as to allow different beam angles and radiation distributions without having to move the patient around. Neither or these features is necessary according to the invention: the invention may also be used with fixed-field devices (no movable plates), with constant radiation delivery rates, and with fixed-angle beams (no rotatable gantry). Radiation treatment device 2 also includes a central treatment processing or control unit 100, which is usually located apart from radiation treatment device 2. The radiation treatment device 2 is normally located in a different room to protect the therapist from radiation. Treatment unit 100 includes output devices, such as at least one visual display unit or monitor 70, and an input device such as a keyboard 19, although data can be input also through data carriers, such as data storage devices, or an verification and recording or automatic set-up system 102, which is described below. The treatment processing unit 100 is typically operated by the therapist who administers actual delivery of a radiation treatment as prescribed by an oncologist. By utilizing the keyboard 19, or other input device, the therapist enters into a control unit 76 of the treatment unit 100 the data that defines the radiation to be delivered to the patient, for example, according to the prescription of the oncologist. The program can also be input via another input device like a data storage device, through data transmission, or using the automatic set-up system 102. On the screen of a monitor 70 various data can be displayed before and during the treatment. FIG. 2 shows portions of an illustrative radiation treatment device 2 and portions of treatment unit 100 in more detail. An electron beam 1 is generated in an electron accelerator 20. Accelerator 20 comprises an electron gun 21, a wave guide 22 and an evacuated envelope or guide magnet 23. A trigger system 3 generates injector trigger signals and supplies them to injector 5. Based on these injector trigger signals, injector 5 generates injector pulses which are fed to electron gun 21 in accelerator 20 for generating electron beam 1. Electron beam 1 is accelerated and guided by wave guide 22. For this purpose, a high frequency (HF) source (not shown) is provided which supplies radio frequency (RF) signals for the generation of an electromagnetic field supplied to wave guide 22. The electrons injected by injector 5 and emitted by electron gun 21 are accelerated by this electromagnetic field in wave guide 22 and exit at the end opposite to electron gun 21 as electron beam 1. Electron beam 1 then enters a guide magnet 23, and from there is guided through a window 7 along axis 10. After passing through a first scattering foil 15, the beam goes through a passageway 51 of a shield block 50 and encounters a second scattering foil 17. Next, it is sent through a measuring chamber 60, in which the dose is ascertained. If the scattering foils are replaced by a target, the radiation beam is an X-ray beam. Finally, aperture plate arrangement 4 is provided in the path of radiation beam 1, by which the irradiated field of the subject of investigation is determined. Aperture plate arrangement 4 includes a pair of plates 41 and 42. As is described above, this is just one example of a beam-shielding arrangement that can be used in the invention. The invention will work with others also as long as there is an aperture plate arrangement that defines an irradiated field. Plate arrangement 4 comprises a pair of aperture plates 41 and 42 and an additional pair of aperture plates (not shown) arranged perpendicular to plates 41 and 42. In order to change the size of the irradiated field the aperture plate can be moved with respect to axis 10 by a drive unit 43 which is indicated in FIG. 2 only with respect to plate 41. Drive unit 43 comprises an electric motor which is coupled to plates 41 and 42 and which is controlled by a motor controller 40. Position sensors 44 and 45 are also coupled to plates 41 and 42, respectively, for sensing their positions. This is just one example of such a system. The invention will work with other systems also, as long as there is a beam-shielding arrangement that defines an irradiated field and as long as sensors are provided to indicate the field size. Motor controller 40 is coupled to a dose control unit 61 which includes a dosimetry controller and which is coupled to a central processing unit 18 for providing set values for the radiation beam for achieving given isodose curves. The output of the radiation beam is measured by a measuring chamber 60. In response to the deviation between the set values and the actual values, dose control unit 61 supplies signals to trigger system 3, which changes in a known manner the pulse repetition frequency so that the deviation between the set values and the actual values of the radiation beam output is minimized. In such a radiation treatment device the dose absorbed by object 13 is dependent on the type of filter used for shaping the radiation beam. If a wedge filter built from absorbing material is inserted in the trajectory of the radiation beam, then the preset dose has to be increased according to the wedge factor in order to supply the desired dose to object 13. FIG. 3 shows isodose curves for a conventional wedge filter 46 in the path of the radiation beam emitted from radiation source 17 to object 13. The radiation beam is shaped on the one hand by the wedge filter and on the other hand by aperture plates 41 and 42. Due to the absorbing material of wedge filter 46, the isodose curve in the center 10 of the beam on object 13 has a maximum value of Dmax, which is the maximum value at a spot in center 10 of the beam on the surface object 13 without wedge filter 46. In the illustrated example, Dmax is roughly 72%. The wedge factor defined as the ratio of doses with and without wedge filter 46 is thus, in this case 0.72. FIG. 4 shows isodose curves in a radiation treatment device according to the invention. Instead of including a wedge-shaped absorber in the path of the radiation beam, the filter function is performed by changing the radiation output of the radiation beam and by simultaneously moving at least one plate 41 and keeping the other plates of plate arrangement 4 stationary. A radiation treatment device having such a filter arrangement is disclosed in U.S. Pat. No. 5,148,032. Although this U.S. Patent describes the possibility of moving any plate, in the following, the invention is described in connection with only one plate being moved and the other plates being kept stationary. This is for the sake of simplicity only. The invention may be used for multiple moving plates as well. When in FIG. 4 plate 41 moves in the direction of arrow A toward plate 42 and at the same time the radiation output is changed according to a desired wedge angle, by adjusting the speed of plate 41 and/or correspondingly, the value of the isodose curve through the center of the beam on the surface of object 13 equals Dmax=100%. Thus, by using a wedge function instead of a wedge-shaped absorber an efficiency factor of "1" or 100% can be established; in other words, the dose delivered at that point is 100% of the prescribed dose, although the same relative isodose profiles are maintained. That means that the therapist does not have to take into account a wedge factor when defining the treatment, although wedge shaped isodose curves are established. FIG. 2 shows those portions of treatment unit 100 which are necessary to carry out the invention. Treatment unit 100 comprises central processing unit 18 and which is programmed by the therapist according to the instructions of the oncologist so that the radiation treatment device carries out the prescribed radiation treatment. Through keyboard 19 the prescribed delivery of the radiation treatment is input. Central processing unit 18 is connected, on the one hand, with the input device, such as the keyboard 19, for inputting the prescribed delivery of the radiation treatment and, on the other hand, with a dose control unit 61 that generates the desired values of radiation for the controlling trigger system 3. Trigger system 3 then adapts the pulse repetition frequency or other parameters in a corresponding, conventional manner. The ability to change the radiation output is generally known and it is particularly advantageous to use a digital dosimetry system because then it can easily be controlled by the digital output of central processing unit 18. Central processing unit 18 includes control unit 76 which controls the execution of the program and which supplies position signals P for controlling the opening of plate arrangement 4 and nominal dose signals D (corresponding to the plate position that would be demanded using prior art methods, that is, without regard to output factor compensation) for adjusting the radiation output at the output of radiation source 17. A memory 77 is also provided in or is connected to the central processing unit 18 for supplying correction signals C, which the processing unit uses to adjust the radiation output dependent on the position signals P supplied from position sensors 44 and 45 in order to achieve the predetermined constant output factor. The preferred arrangement of the memory unit is that, for each plate position (field size), it has stored a corresponding wedge correction signal C. The memory thus stores a table of wedge correction factors. If more than one set of movable plates is included in the system, then the table will be correspondingly multi-dimensional, and arranged using any known data structure, so that a wedge correction factor is available for any combination of plate positions. Control unit 76 and memory 77 apply the nominal dose and wedge correction signals D and C, respectively, to a combination circuit 78, which combines the values to generate set signals S. The set signals S are in turn applied to the dose control unit 61, which sets the radiation output. The combination circuit 78 will depend on the form in which the wedge correction signals are generated and stored. Assume that the wedge correction signals C are stored as additive offsets to the set radiation output. In this case, the combination circuit will be an adder which adds the wedge correction signals C to nominal dose signals D. This is the preferred embodiment, since it is simplest. If, however, the wedge correction factors are multipliers, for example, an increase in radiation output from a sensed value of 72% would require a multiplicative correction signal of about 139%. Instead of storing actual values of the wedge correction signals C, it is also possible to store the parameters of a wedge correction function for the various field sizes. The processing unit would then evaluate the wedge correction function for each current field size using the parameters stored in the memory, and would then generate the wedge correction signals (additive or multiplicative) itself. The wedge correction signals are determined before actual treatment of a patient in one or more calibration runs. To determine relative wedge correction values, a reference surface is irradiated with a known reference plate position, and the radiation output over the surface is sensed by a conventional sensing device (not shown), which generates radiation output signals, which are applied to the processing unit 18. In particular, the radiation output at a reference point (for example, at the center of the beam) is sensed. The reference surface need not lie in the patient plane, although if it does the calibration will typically be easier and more accurate. The plates are then moved to a new opening position, the radiation output is sensed and the needed amount of adjustment is determined to create the proper isodose profile for that position. This process is continued until correction values are stored for the reference surface over the entire range of motion of the plates. If more than one set of movable plates is included, then correction values will be sensed and stored for each combination of plate positions; the number of combinations will depend on the desired or required resolution. The correction values indicate by how much the radiation output (for example, dose rate) is to be changed (via the wedge correction signals) such that the delivered dose distribution is equal to the desired dose distribution, that is, the isodose profiles are generated corresponding to what they would be if the radiation output were held constant and a physical wedge were included in the beam path. During actual treatment, for each plate position, the processing unit adjusts the radiation output to correspond to what is needed to generate the correct isodose profile. Since no actual physical wedge is included, however, and the system is calibrated for 100% output at the reference point, the therapist need not perform any calculations to adjust for a wedge factor. If additive offsets are chosen for the wedge correction factors, then the difference between the sensed output values and the desired output value is stored. If multiplicative correction factors are chosen, then ratios are stored. Alternatively, any known function approximation method may be used to generate the parameters of an approximating function of the additive or multiplicative wedge correction factors required. A "course" of radiation treatment may, and often does, have more than one field, and may run over several different sessions. In some cases, hundreds of different (and, in some cases, fixed) sequential fields with different wedges are used during a course, for example, to provide proper irradiation of a field that has a complicated geometry or prescribed dose profile, to lessen discomfort to the patient, or to adjust the field as a tumor shrinks during treatment. The invention therefore also comprises an optional verification and recording or "auto set-up" system 102 (see FIG. 2), which stores and downloads to the radiation system (via the CPU 18 or directly into the memory) the parameters, for example, of the geometry, of the various fields of the course of treatment, and/or the tables of wedge correction factors that were derived during earlier calibration runs for the various fields.
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	claims	1. A process for production of radiostrontium comprising the steps of:bombarding a hermetically sealed target containing metallic rubidium inside a target shell, with a beam of accelerated protons;melting of the rubidium inside the target shell after the bombarding thereof to yield a rubidium-containing liquid composition;extracting radiostrontium from the rubidium-containing liquid composition via sorption at the temperature in the range of 275-350° C. on a sorbing surface of the target shell in contact with the rubidium-containing liquid composition;removing the rubidium-containing liquid composition from the target shell; andwashing radiostrontium with a solvent from the sorbing surface;wherein the rubidium-containing liquid composition contains oxygen in an amount of 0.1 to 4 wt %. 2. The process according to claim 1, wherein the material of the rubidium target shell is stainless steel, tantalum, niobium, tungsten, molybdenum, nickel, or a noble metal or a mixture thereof. 3. The process according to claim 1, wherein the radiostrontium is washed from the inner target shell surface with organic alcohols, water, or hydrochloric acid or a mixture thereof. 4. A process for production of radiostrontium comprising the steps of:bombarding a target made of metallic rubidium with a beam of accelerated protons;melting of the rubidium to yield a rubidium-containing liquid composition;extracting radiostrontium from the rubidium-containing liquid composition by circulating the rubidium-containing liquid composition during bombarding through a closed loop equipped with a trap wherein the loop is maintained at a temperature in the range from 10 to 200° C., wherein radiostrontium is extracted from the rubidium-containing liquid composition via sorption on the sorbing surface on parts of the trap heated to a temperature in the range of 220-350° C. which is in contact with the rubidium-containing liquid composition; andwashing radiostrontium with a solvent from the surface of the parts of the trapwherein the rubidium-containing liquid composition contains oxygen in an amount of no more than 3.0 wt %. 5. The process according to claim 4 wherein the material of parts of the trap is stainless steel, tantalum, niobium, titanium, zirconium, tungsten, molybdenum, nickel, or a noble metal or a mixture thereof. 6. The process according to claim 4 wherein radiostrontium is washed from the surface of parts of the trap with organic alcohols, water, or hydrochloric acid or a mixture thereof. 7. A process for producing radiostrontium comprising the steps of:bombarding a target made of metallic rubidium with a beam of accelerated protons;melting of the rubidium to yield a rubidium-containing liquid composition;extracting radiostrontium from the rubidium-containing liquid composition by circulating the rubidium-containing liquid composition during bombarding through a closed loop equipped with a trap wherein the loop is maintained at a temperature in the range from 10 to 38° C., and filtering the rubidium-containing liquid composition through a filtering unit made of a porous material comprising stainless steel, tantalum, niobium, titanium, zirconium, tungsten, molybdenum, nickel, or noble metals, wherein radiostrontium is extracted from the rubidium-containing liquid composition via sorption on a sorbing surface on parts of the filtering unit in contact with the rubidium-containing liquid composition;washing radiostrontium with a solvent from the surface of the parts of the filtering unit,wherein the rubidium-containing liquid composition contains oxygen in an amount of 0.1 to 4.0 wt %. 8. The process according to claim 7 wherein radiostrontium is washed from the surface of the filtering unit with organic alcohols, water, or hydrochloric acid or a mixture thereof. 9. The process according to claim 7, wherein the target is hermetically sealed.
	abstract	A focused ion beam apparatus and a focused ion beam irradiation method are disclosed. Even in the case where a magnetic field exists on the optical axis of an ion beam and the particular magnetic field undergoes a change, the ion beam is focused without separating the isotopes on the sample at the same ion beam spot position as if the magnetic field is not existent. A canceling magnetic field is generated on the optical axis of the ion beam from a canceling magnetic field generator thereby to offset the deflection of the ion beam due to the external magnetic field.
062228978	description	DETAILED DESCRIPTION FIG. 1 is a side view of a scan apparatus 100 positioned about a pipe elbow 102. Apparatus 100 can inspect piping 104 and welds 106 of pipe elbows 102 in a reactor pressure vessel (not shown) of a boiling water reactor (not shown). Apparatus 100 includes a scan head 108 having at least one ultrasonic transducer 110 and a motor 112 that moves scan head 108 along a pipe elbow axis 114. In one embodiment, scan head 108 includes a pair of spaced apart ultrasonic transducers 110. Scan head 108 allows transducers 110 to remain substantially in contact with pipe elbow 102 while scan head 108 traverses pipe elbow 102. Ultrasonic transducers 110 can detect flaws in piping 104 and welds 106 of pipe elbows 102. Transducers 110 are contoured to conform to piping 104. Scan apparatus 100 further includes a scan platform 116 and a pivot arm 118 having a first end 120 and a second end 122. Pivot arm 118 connects scan platform 116 to a pivot pin 124. Specifically, pivot arm second end 122 is connected to scan platform 116 and pivot arm first end 120 is connected to pivot pin 124. Motor 112 pivots pivot arm second end 122 about pivot pin 124. The connection of scan head 108 to pivot arm second end 122 allows ultrasonic transducers 110 to pivot substantially about pivot pin 124 when pivot arm second end 122 pivots about pivot pin 124. FIGS. 2 and 3 are bottom views of scan apparatus 100 including a pair of transducer probes 126 including ultrasonic transducers 110, a connector 128, and a pair of transducer arms 130 each having a first end 132 and a second end 134. Each transducer arm first end 132 is connected to one of transducer probes 126. Connector 128 connects both transducer arm second ends 134 to scan platform 116 which is connected to motor 112. Connector 128, transducer arms 130, and transducer probes 126 form a gimbals that allows ultrasonic transducers 110 to orbit freely about scan platform 116. This freedom of movement of ultrasonic transducers 110 allows ultrasonic transducers 110 to remain in contact with pipe elbow 102 throughout the movement of scan head 108 along pipe elbow 102. Scan platform 116 includes an arcuate cutout 136 having a size and shape to accommodate piping 104. Connector 128 slides along arcuate cutout 136. As connector 128 slides along cutout 136, ultrasonic transducers 110 rotate, at least partially, about a circumference of piping 104. FIG. 4 is a top view of scan apparatus 100 showing connector 128, scan platform 116, and arcuate cutout 136. Connector 128 is positioned at an end of its sliding movement and ultrasonic transducers 110 are rotated fully to their rightmost position. In operation, piping 104 and welds 106 of pipe elbow are inspected using scan apparatus 100 by a method that includes positioning scan head 108 and at least one transducer probe 126 such that at least one ultrasonic transducer 110 is in substantial contact with a pipe elbow surface 138. In one embodiment, there are two transducer probes 126, each holding one ultrasonic transducer 110. Ultrasonic transducers 110 are in substantial contact with pipe elbow surface 138 and are spaced approximately 180 degrees apart. Scan head 108 is then moved axially along pipe elbow 102 by utilizing motor 112 to pivot ultrasonic transducers 110 substantially about pivot pin 124. This axial movement allows transducer probes 126 to travel axially along pipe elbow 102 while ultrasonic transducers 110 remain in substantial contact with pipe elbow surface 138. The step of moving scan head 108 includes pivoting scan head 108 up to about 90 degrees to accommodate a bend in pipe elbow 102 and to enable scan head 108 to access all pipe elbow surfaces 138. During the axial movement, scan head 108 inspects piping 104 and welds 106 in pipe elbow 102 to detect flaws. Scan apparatus 100 moves with a wrist scan motion to enhance the ability of transducer probes 126 to remain in contact with pipe elbow surface 138 during inspection and to enable ultrasonic transducer signals to better penetrate piping 104 and welds 106 of pipe elbow 102. Piping 104 and welds 106 of pipe elbow 102 are inspected as transducer probes 126 move substantially perpendicular to welds 106. FIG. 5 is a side view of a scan apparatus 100 positioned about pipe elbow 102 at a first axial point 140. The axial movement of scan head 108 occurs along pipe elbow 102 in a first direction from first axial point 140 to a second axial point 142. Connector 128 then slides along arcuate cutout 136, incrementally rotating, in a raster type manner, transducer probes 126. Scan head 108 then moves axially along pipe elbow 102 in a second direction from second axial point 142 to first axial point 140. Again, connector 128 slides along cutout 136, incrementally rotating, in a raster type manner, transducer probes 126. Each incremental rotation of transducer probes 126 moves transducer probes 126 about a partial circumference of piping 104. The axial movement of transducer probes 126 and the incremental rotation at the ends of the axial movement are repeated until transducer probes 126 have investigated pipe elbow surface 138 in its entirety. A method of positioning ultrasonic transducer probes 126 to examine piping 104 and welds 106 of pipe elbow 102 includes locating scan apparatus 100 at pipe elbow 102. Since scan apparatus 100 is for use in a reactor pressure vessel of a boiling water reactor, scan apparatus 100 can be deployed in water to a depth of more than about 60 feet. Scan head 108 is then adjusted to allow at least a portion of piping 104 to enter arcuate cutout 136. The next step includes positioning transducer probes 126 substantially in contact with pipe elbow 102, and moving scan head 108 axially along pipe elbow 102. Transducer probes 126 are maintained in substantial contact with pipe elbow 102 throughout the movement of scan head 108 axially along pipe elbow 102. The axial movement of pipe elbow 102 begins at first axial point 140 and moves in a first direction to second axial point 142. Connector 128 is then moved incrementally along arcuate cutout 136 which causes transducer probes 126 and transducer arms 130 to rotate partially about a circumference of piping 102. Scan head 108 is then moved axially along pipe elbow 102 in a second direction from second axial point 142 to first axial point 140. Again, connector 128 is moved incrementally along arcuate cutout 136 which causes transducer probes 126 and transducer arms 130 to rotate partially about the circumference of piping 104. The axial movement of transducer probes 126 and the incremental rotation at the completion of the axial movement are repeated until transducer probes 126 have investigated pipe elbow surface 138 in its entirety. Scan apparatus 100 can be applied to various diameter piping 104 and enables volumetric examination of entire pipe elbows 102. Transducer probes 126 can maintain contact with pipe elbow surface 138 due, at least in part, to the connections between transducer probes 126 and scan platform 116. These connections provide a wrist scan motion that enhances the ability of transducer probes 126 to contour to pipe elbow surface 138 and enables ultrasonic transducer signals to better penetrate pipe elbow surface 138. From the preceding description of various embodiments of the present invention, it is evident that the objects of the invention are attained. Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is intended by way of illustration and example only and is not to be taken by way of limitation. Accordingly, the spirit and scope of the invention are to be limited only by the terms of the appended claims.
	summary
	summary
	abstract	A spacecraft and spacesuit having a radiation shield are disclosed. The shield comprises a hydrogen-containing material encapsulated or bound in a polymer. The hydrogen-containing material has a higher hydrogen content than polyethylene. The hydrogen-containing material may be: encapsulated in a polymer container, sandwiched between layers of polymer, mixed with a polymer as binder, or held in the pores of a polymer foam. The hydrogen may be a hydride or borohydride such as beryllium borohydride, ammonium octahydrotriborate, lithium borohydride tetramethyl ammonium borohydride and beryllium hydride. Methods of manufacturing the shield are also disclosed.
	summary
	claims	1. A diagnostic system for protecting a tap-changer comprising:a sensor, positioned to detect temperature changes;an initial measured temperature, indicating an initial temperature measured by said sensor prior to initiating a tap change;a calculated temperature value, calculated according to the particular tap change to take place;a threshold value determined based on said initial measured temperature and said calculated temperature value, at which an alarm is generated;a second measured temperature indicating an actual temperature measured by said sensor after a tap change has been initiated;said alarm generated by the diagnostic system if said second measured temperature exceeds said threshold value. 2. The diagnostic system according to claim 1, further comprising a second threshold value above which, flow of electrical power through said tap-changer will be interrupted. 3. The diagnostic system according to claim 2, in which said second threshold value is higher than said first threshold value. 4. A diagnostic system for preventing degradation to electrical contacts in a tap-changer comprising:a contact measurement device for measuring a contact position;a contact signal generated by said contact measurement device, indicative of whether the contact is open or closed;a threshold time value related to a maximum amount of time that the contact may be in the contact position;a controller for receiving the contact signal and generating a closed time value based on the contact signal;said controller comparing the closed time value to said threshold time value to determine if the closed time value exceeds said threshold time value;a warning message generated by the diagnostic system indicating that said threshold time value has been exceeded. 5. The diagnostic system according to claim 4, further comprising a temperature sensor located in the vicinity of the contact to measure temperature and generate a temperature signal, said controller receiving the temperature signal and determining whether the warning message should be generated based on both the threshold time value and the temperature signal. 6. The diagnostic system according to claim 5, wherein the higher the temperature signal, the shorter the threshold time value must be for the system to generate the warning message. 7. The diagnostic system according to claim 4, further comprising a current sensor to measure current through the contact and generate a current signal, said controller receiving the current signal and determining whether the warning message should be generated based on both the threshold time value and the current signal. 8. The system according to claim 7, wherein the higher the current signal, the shorter the threshold time value must be for the system to generate the warning message. 9. The diagnostic system according to claim 4, further comprising:a temperature sensor located in the vicinity of the contact to measure temperature and generate a temperature signal;a current sensor to measure current through the contact and generate a current signal;said controller receiving the temperature signal and the current signal and determining whether the warning message should be generated based on, the threshold time value, the temperature signal, and the current signal. 10. The system according to claim 9, wherein the higher the temperature signal and/or the higher the current signal, the shorter the threshold time value must be for the system to generate the warning message.
046876243	claims	1. A liquid metal cooled fast breeder reactor, including a reactor vessel, a reactor core within said reactor vessel, a shield plug device adapted to seal an upper opening of said reactor vessel, said shield plug device consisting of a fixed plug and at least a single rotating plug eccentrically rotatively mounted to said fixed plug, an upper core structure extending downwardly through said rotating plug toward said reactor core, and a fuel handling mechanism suspended vertically down into said reactor vessel through said rotating plug, said fuel handling mechanism comprising: a fuel handling body, a rotational driving device, mounted on said rotating plug so as to reduce therewith, for rotationally driving said fuel handling body with respect to said rotating plug about a fuel handling body axis of rotation, said rotational driving device supporting an upper portion of said fuel handling body, and an aseismatic support fixed to and extending radially outwardly from said upper core structure, said aseismatic support securing a lower portion of said fuel handling body and including means for fixing said lower portion against radial and circumferential movement with respect to said upper core structure. a fuel handling body, a rotational driving device, mounted on said rotating plug so as to rotate therewith, for rotationally driving said fuel handling body with respect to said rotating plug about a fuel handling body axis of rotation, said rotational driving device supporting an upper portion of said fuel handling body, and an aseismatic support extending radially outwardly from said upper core structure, said aseismatic support securing a lower portion of said fuel handling body and including a securing ring fixed to the outer surface of said upper core structure, a holder having a plurality of radially outwardly extended projections, said holder being fixed to said fuel handling body, and a plurality of rolling elements, each being rotatably held between said projections and said securing ring, for permitting said holder to move circumferentially within said securing ring. 2. A liquid cooled fast breeder reactor according to claim 1, wherein said fuel handling body extends downward through said rotating plug into said reactor vessel and said fuel handling body axis of rotation is horizontally spaced from said upper core structure. 3. A liquid cooled fast breeder reactor according to claim 1 wherein said rotational driving device comprises means for supporting said fuel handling body above said rotating plug. 4. A liquid cooled fast breeder reactor according to claim 1, further comprising a gripper for gripping fuel rods at a position radially spaced from said fuel handling body axis of rotation, mounted to a lower end of said fuel handling body so as to extend radially outward from said fuel handling body axis of rotation and rotate with rotation of said fuel handling body by said rotational driving device. 5. A liquid metal cooled fast breeder reactor, including a reactor vessel, a reactor core within said reactor vessel, a shield plug device adapted to seal an upper opening of said reactor vessel, said shield plug device consisting of a fixed plug and at least a single rotating plug eccentrically rotatably mounted to said fixed plug, an upper core structure extending downwardly through said rotating plug toward said reactor core, and a fuel handling mechanism suspended vertically down into said reactor vessel through said rotating plug, said fuel handling mechanism comprising: 6. The liquid metal cooled fast breeder reactor according to claim 5, wherein said aseismatic support is further provided with a fender, said fender being positioned on said upper core structure and at a position slightly above said securing ring.
	abstract	A writing apparatus including a selector unit responsive to receipt of input data of a pattern to be written by shots of irradiation of an electron beam, configured to select a current density of the electron beam being shot and a maximal shot size thereof based on the input data of the pattern to be written; and a writing unit configured to create an electron beam with the current density selected by said selector unit, shape the created electron beam into a shot size less than or equal to said maximal shot size in units of the shots, and shoot the shaped electron beam onto a workpiece to thereby write said pattern.
039649687	summary	The present invention relates to nuclear reactors, and, more particularly, to a nuclear reactor fuel assembly primarily employed in fast reactors with a liquid-metal heat transfer fluid. BACKGROUND OF THE INVENTION It is known in the art to employ a nuclear reactor fuel assembly wherein at least some of the fuel elements are provided with spacer members, each formed as a wire arranged in a helical line on the lateral surface of each of said fuel elements and adjoining, in the contact planes, the fuel elements in immediate proximity to those fuel elements which carry said spacer members. This practice is used in most operating fast reactors with a sodium coolant. The spacer member used herein is a structural element designed for space fixation of fuel elements. In the fuel assembly of this type of reactor, the spacer member is formed as a single wire fixed on the ends of each fuel element, and forcibly wound in a helical line about the lateral surface thereof. Each fuel element of the fuel assembly is fixed at a required number of points, vertically and perimetrically, through contact with the spacer members disposed on the adjacent fuel elements. It is obvious from the above that with such a design of the fuel assembly, a modification of the principle is possible whereby only some, but not all, of the fuel elements are provided with spacer members. The spacer member formed as a single wire helically arranged on the lateral surface of the fuel element is of fairly simple design, but one which nevertheless provides for the required tightness for the packing of the fuel elements in the fuel assembly and for their secure fixation, as well as for satisfactory thermal and hydraulic characteristics of the fuel assembly as a whole. These advantages account for the wide popularity of the foregoing fuel assembly design in the world reactor-manufacturing industry. As far as high-power fast reactors are concerned, however, the core elements are exposed to entirely different conditions and altogether new operating factors are involved. Thus, exposure to high integrated neutron fluxes (on the order of 10.sup.23 1/sq.cm. and higher), typical of such reactors, causes the jackets of the fuel elements to swell to a considerable degree, with their outer diameter increasing by as much as several percent (.DELTA. d/d.sub.o). In the above-described fuel assembly, the resultant lateral deformation of the fuel elements will cause an inadmissible degree of deformation of the assembly housing and induce additional contact stresses in the jackets of the fuel elements contacting one another by way of the highly rigid spacer members, with the result that the possible service life of the fuel elements will be severely shortened, the fuel cycle costs raised and the general reactor economics adversely affected. SUMMARY OF THE INVENTION It is an object of the present invention to provide a nuclear reactor fuel assembly of such a design that would ensure a longer service life of the constituent fuel elements. The foregoing object is attained by the fact that in a nuclear reactor fuel assembly, wherein at least some of the fuel elements are provided with spacer members formed as a wire arranged in a helical line on the lateral surface of those fuel elements and adjoining, in planes of cntact, the adjacent fuel elements, in accordance with the invention, each spacer member is provided with at least two additional wires which together with the main wire define a bunch of wires, wherein each of the wires adjoins at least two adjacent wires along the entire length thereof, with all the wires being rigidly interconnected between said planes of contact. The proposed nuclear reactor fuel assembly ensures a longer service life for its cnstituent fuel elements, and is also conductive to a more economical fuel cycle for high speed breeder power reactors wherein it is employed.
	description	This application claims the benefit of Japanese Application No. 2006-055417 filed Mar. 1, 2006. The present invention relates to an X-ray CT apparatus which is a medical X-ray CT (Computed Tomography) apparatus or an industrial X-ray CT apparatus and which holds operations of an X-ray data acquisition system or information for imaging conditions and performs image reconstruction based on the same, upon a conventional scan (axial scan), a cine scan, a helical scan, a variable-pitch helical scan or a helical shuttle scan. An X-ray CT apparatus acquires X-ray projection data by scanning a subject with X rays and image-reconstructs a tomographic image of the subject, based on the X-ray projection data (refer to, for example, Japanese Unexamined Patent Publication No. 2004-173756). Such an X-ray CT apparatus has a two-dimensional X-ray area detector of a matrix structure typified by, for example, a multi-row X-ray detector or a flat panel. Upon data acquisition by a conventional scan (axial scan), a cine scan or a helical scan, a scanning table is changed in a z direction by the operation of an X-ray data acquisition system during scan to perform X-ray data acquisition. In the case of a variable-pitch helical scan and a helical shuttle scan, an absolute coordinate position or a relative coordinate position of a z-direction coordinate of the scanning table is recorded for each view or at several views as position information of the scanning table. Described specifically, when a scanning table velocity changes like v(t) as shown in FIG. 16, a scanning table position changes like z(t) and a data acquisition view number linearly increases like N(i). Therefore, for example, data of a scanning table position z(t1) is recorded so as to correspond to an N(t1) view. Incidentally, the data of the scanning table position z(t1) may be recorded with being added to X-ray projection data. Here, an encoder for detecting a position is installed in the scanning table as in the case of a rotary encoder, a linear encoder or the like, and the installed encoder is used to obtain data about each position of the scanning table in real time during scan. For example, X-ray projection data and position data of the scanning table at the time that the X-ray projection data is obtained, are stored in association with each other. For example, as file data different from the X-ray projection data, the position data of the scanning table is stored in association with it each other. Thereafter, image reconstruction is carried out using the X-ray projection data and the position data of the scanning table both associated with each other, thereby to obtain a tomographic image of the subject. Therefore, there is a case in which the addition of the X-ray projection data to each view is not easy. Further, there was a case where when z-direction coordinate information of the scanning table corresponding to each view was contained as another file, it was not easy to associate the z-direction coordinate information of the scanning table and each view for the X-ray projection data with each other upon image reconstruction. Thus, there was a case in which a problem arose in that the association of the X-ray projection data and the scanning table z-direction coordinate information with each other upon the X-ray projection data acquisition or image reconstruction was not easy. In an X-ray CT apparatus having a multi-row X-ray detector or an X-ray CT apparatus having a two-dimensional X-ray area detector typified by a flat panel, there is a tendency to increase the number of channels of an X-ray detector and increase the number of views for X-ray projection data as the resolution in a row direction rises. Further, there is a tendency to make the rotational velocity of the gantry fast. That is, the number of views per unit time trends to increase. A z-direction position of a scanning table or cradle is measured by the scanning table. Its z-direction position data is added to X-ray projection data obtained by a data acquisition system (DAS) of a scanning gantry rotating section at a scanning gantry fixing section. Therefore, this control becomes difficult due to the increase in the number of views per unit time. Thus, an object of the present invention is to provide an X-ray CT apparatus capable of efficiently describing and storing position information and photography information of an X-ray data acquisition system by less parameters. When an operator sets an imaging condition, the operations of an X-ray data acquisition system and a scanning table or cradle are determined. The scanning table or cradle will be explained below as the scanning table. That is, as the operations of the X-ray data acquisition system and the scanning table with a subject placed thereon, a scanning table z-direction coordinate position, a scanning table x-direction coordinate position, a scanning table y-direction coordinate position, a scanning gantry rotating section rotation-angle position, a scanning gantry tilt angle position, a scanning gantry x-direction coordinate position, a scanning gantry y-direction coordinate position, and a scanning gantry z-direction coordinate position are predicted upon setting of the imaging condition. Since the X-ray data acquisition system and the scanning table are normally feedback-controlled with an accuracy of 0.1 mm or less, they do not deviate vastly from their predicted values. Therefore, if the predicted operations of X-ray data acquisition system and scanning table can be described by several parameters, then the operations of the X-ray data acquisition system and the scanning table can be reproduced if the parameters are recorded. FIG. 17 describes the manner of traveling of the scanning table (or cradle) in the z direction. If parameters for cradle acceleration, cradle deceleration, a cradle stationary velocity, a cradle initial position, a cradle stop position, a cradle acceleration end position and a cradle deceleration start position exist, then the operation of the scanning table or cradle can be described. If the scanning gantry and the scanning table corresponding to the X-ray data acquisition system can be moved with sufficient accuracy as predicted based on the parameters, it is then unnecessary to subject information about a scanning table z-direction coordinate position, a scanning table x-direction coordinate position, a scanning table y-direction coordinate position, a scanning gantry rotating section rotation-angle position, a scanning gantry tilt angle position, a scanning gantry x-direction coordinate position, a scanning gantry y-direction coordinate position, and a scanning gantry z-direction coordinate position set for each view to measurement, data acquisition and addition to X-ray projection data. Therefore, in the present invention, the operation of a scanning gantry corresponding to an X-ray data acquisition system, and the operation of a scanning table or cradle are predicted when an operator sets an imaging condition, and described with operation parameters. When the parameters are added to X-ray projection data upon X-ray data acquisition to perform image reconstruction, the image reconstruction is carried out using the operation parameters. Alternatively, the operation parameters are inserted into another file and associated with the X-ray projection data. Upon execution of image reconstruction, the image reconstruction is carried out using the operation parameters. In order to solve the above problems, there is provided an X-ray CT apparatus according to a first aspect, comprising a scanning table for placing a subject thereon and moving the subject placed thereon; a scanning gantry comprising an X-ray generator, an X-ray detector for detecting the X rays in opposition to the X-ray generator, and a rotation device for rotating the X-ray generator and the X-ray detector, for causing the X-ray generator to expose X rays to the subject moved by the scanning table while the X-ray generator and the X-ray detector are being rotated about the subject, and performing a scan for causing the X-ray detector to detect the X rays transmitted through the subject thereby to acquire X-ray projection data; image reconstructing device for image-reconstructing the X-ray projection data acquired by the scanning gantry; image display device for displaying a tomographic image reconstructed by the image reconstructing device; and imaging condition setting device for setting an imaging condition including a parameter for operating the scanning gantry and/or a parameter for causing the scanning table to move the subject upon execution of the scan, wherein the image reconstructing device reconstructs the X-ray projection data using the parameter for operating the scanning gantry and/or the parameter for causing the scanning table to move the subject set by the imaging condition setting device as the imaging condition. In the X-ray CT apparatus according to the first aspect, the operations of an X-ray data acquisition system comprising the X-ray data acquisition device and the scanning table are recognized in advance by operation parameters. Since the position of an X-ray beam passing through each pixel on an image reconstruction plane can be predicted properly upon image reconstruction, the image reconstruction can be carried out with a high degree of accuracy. In order to solve the above problems, there is provided an X-ray CT apparatus according to a second aspect, wherein in the X-ray CT apparatus according to the first aspect, the X-ray data acquisition device adds the parameters set as the imaging condition by the imaging condition setting device to the X-ray projection data and records the result of addition therein. In the X-ray CT apparatus according to the second aspect, the operations of an X-ray data acquisition system comprising the X-ray data acquisition device and scanning table are recognized in advance by operation parameters, and the operation parameters are added to X-ray projection data. Since the position of an X-ray beam passing through each pixel on an image reconstruction plane can be predicted properly based on the operation parameters added to the X-ray projection data upon image reconstruction, the image reconstruction can be performed accurately. In order to solve the above problems, there is provided an X-ray CT apparatus according to a third aspect, wherein the X-ray data acquisition device records, as parameters for the operations of the X-ray data acquisition device and the scanning table, data containing at least one of a scanning table z-direction coordinate position, a scanning table x-direction coordinate position, a scanning table y-direction coordinate position, a scanning gantry rotating section rotation-angle position, a scanning gantry tilt angle position, a scanning gantry x-direction coordinate position, a scanning gantry y-direction coordinate position, and a scanning gantry z-direction coordinate position. In the X-ray CT apparatus according to the third aspect, even when the scanning gantry, and the X-ray data acquisition device and scanning table lying thereinside are allowed to perform photography and diagnoses by various applications or various operations, the operations of the X-ray data acquisition system comprising the X-ray data acquisition device and scanning table lying in the scanning gantry are recognized more by respective operation parameters. If the scanning gantry and the X-ray data acquisition device and scanning table lying thereinside can be moved with satisfactory accuracy as recognized, then an X-ray beam passing through each pixel on an image reconstruction plane can be predicted properly upon image reconstruction. Therefore, the image reconstruction can be carried out accurately. There is provided an X-ray CT apparatus according to a fourth aspect, wherein in the X-ray CT apparatus according to any of the first to third aspects, an X-ray data acquisition system has X-ray data acquisition device which records at least one of at least one absolute coordinate value or relative coordinate value of a scanning table z-direction coordinate position, a scanning table x-direction coordinate position, a scanning table y-direction coordinate position, a scanning gantry rotating section rotation-angle position, a scanning gantry tilt angle position, a scanning gantry x-direction coordinate position, a scanning gantry y-direction coordinate position, and a scanning gantry z-direction coordinate position. In order to solve the above problems, in the X-ray CT apparatus according to the fourth aspect, the operation parameters set by the scanning gantry, and the X-ray data acquisition device and scanning table lying thereinside are recorded using the absolute coordinate value and the relative coordinate value when the operation parameters are recorded in the third aspect. Since the position of an X-ray beam passing through each pixel on an image reconstruction plane can be properly predicted absolutely or relatively upon image reconstruction, the image reconstruction can be carried out accurately. In order to solve the above problems, there is provided an X-ray CT apparatus according to a fifth aspect, wherein in the X-ray CT apparatus according to any of the first to fourth aspects, an X-ray data acquisition system has X-ray data acquisition device which records at least one of at least one absolute coordinate value or relative coordinate value of a scanning table z-direction coordinate position, a scanning table x-direction coordinate position, a scanning table y-direction coordinate position, a scanning gantry rotating section rotation-angle position, a scanning gantry tilt angle position, a scanning gantry x-direction coordinate position, a scanning gantry y-direction coordinate position, and a scanning gantry z-direction coordinate position and adds the same to X-ray projection data. In the X-ray CT apparatus according to the fifth aspect, when the operation parameters set by the scanning gantry, and the X-ray data acquisition device and scanning table lying thereinside are recorded in the third or fourth aspect, they are recoded with being added to X-ray projection data. It is thus unnecessary to associate the operation parameters with another file where they are set as another file. Therefore, the operation of the X-ray data acquisition device can be predicted on software of an image reconstruction device according to a simpler file operation upon image reconstruction. Further, the position of an X-ray beam passing through each pixel on an image reconstruction plane can properly be predicted upon image reconstruction. It is therefore possible to carry out the image reconstruction accurately. In order to solve the above problems, there is provided an X-ray CT apparatus according to a sixth aspect, wherein in the X-ray CT apparatus according to any of the first to fifth aspects, the X-ray data acquisition device records at least one of accelerations or decelerations about operations in a scanning table z direction, a scanning table x direction, a scanning table y direction, a scanning gantry rotating section rotation-angle direction, a scanning gantry tilt angle direction, a scanning gantry x-direction angle direction, a scanning gantry y-direction angle direction and a scanning gantry z-direction angle direction of an X-ray data acquisition system. In the X-ray CT apparatus according to the sixth aspect, the acceleration and deceleration at each time are contained in the operation parameters set by the scanning gantry corresponding to the X-ray data acquisition device, and the X-ray data acquisition device thereinside and scanning table lying in the first to fifth aspects. Since the velocities and travel distances for the operations are known from this point, the prediction of the operations can be carried out properly. Thus, since the position of an X-ray beam passing through each pixel on an image reconstruction plane can be properly predicted upon image reconstruction, the image reconstruction can be carried out accurately. In order to solve the above problems, there is provided an X-ray CT apparatus according to a seventh aspect, wherein in the X-ray CT apparatus according to any of the first to sixth aspects, the X-ray data acquisition device records at least one of initial positions, stop positions, acceleration end positions or deceleration start positions about operations in a scanning table z direction, a scanning table x direction, a scanning table y direction, a scanning gantry rotating section rotation-angle direction, a scanning gantry tilt angle direction, a scanning gantry x-direction angle direction, a scanning gantry y-direction angle direction and a scanning gantry z-direction angle direction of an X-ray data acquisition system. In the X-ray CT apparatus according to the seventh aspect, the initial positions, stop positions, acceleration end positions or deceleration start positions about the operations are contained in the operation parameters set by the scanning gantry corresponding to the X-ray data acquisition device, and the X-ray data acquisition device and scanning table lying thereinside in the first to sixth aspects. From this point, the position of the X-ray data acquisition system is known in combination with the acceleration and deceleration, so the prediction of the operations can be carried out properly. Thus, since the position of an X-ray beam passing through each pixel on an image reconstruction plane can be predicted properly upon image reconstruction, the image reconstruction can be carried out accurately. In order to solve the above problems, there is provided an X-ray CT apparatus according to an eighth aspect, wherein in the X-ray CT apparatus according to any of the first to seventh aspects, the X-ray data acquisition device records stationary velocities about operations in a scanning table z direction, a scanning table x direction, a scanning table y direction, a scanning gantry rotating section rotation-angle direction, a scanning gantry tilt angle direction, a scanning gantry x-direction angle direction, a scanning gantry y-direction angle direction and a scanning gantry z-direction angle direction of an X-ray data acquisition system. In the X-ray CT apparatus according to the eighth aspect, the steady-state or stationary velocities are contained in the operation parameters set by the scanning gantry corresponding to the X-ray data acquisition device, and the X-ray data acquisition device and scanning table lying thereinside in the first to seventh aspects. From this point, the position of the X-ray data acquisition system can be reconfirmed, and the prediction of each operation reduced in error can be carried out properly. Thus, since the position of an X-ray beam passing through each pixel on an image reconstruction plane can be predicted properly upon image reconstruction, the image reconstruction can be carried out accurately. In order to solve the above problems, there is provided an X-ray CT apparatus according to a ninth aspect, wherein in the X-ray CT apparatus according to any of the first to eighth aspects, when X-ray projection data corresponding to respective views are image-reconstructed, the image reconstructing device reproduces position information of an X-ray data acquisition system to perform image reconstruction. In the X-ray CT apparatus according to the ninth aspect, there is a need to reproduce the position information of the X-ray data acquisition system by the operation parameters upon image reconstruction in the first to eighth aspects. Thus, since the position of an X-ray beam passing through each pixel on an image reconstruction plane can be predicted properly upon image reconstruction, the image reconstruction can be performed accurately. In order to solve the above problems, there is provided an X-ray CT apparatus according to a tenth aspect, wherein in the X-ray CT apparatus according to any of the first to ninth aspects, the operations of an X-ray data acquisition system about a scanning table z direction, a scanning table x direction, a scanning table y direction, a scanning gantry rotating section rotation-angle direction, a scanning gantry tilt angle direction, a scanning gantry x-direction angle direction, a scanning gantry y-direction angle direction and a scanning gantry z-direction angle direction of an X-ray data acquisition system are linear control. In the X-ray CT apparatus according to the tenth aspect, the operations of the scanning gantry corresponding to the X-ray data acquisition device, and the X-ray data acquisition device and scanning table lying thereinside are linearly-controlled. Consequently, the prediction of the operations becomes simple and hence the burden on a control system is reduced. Thus, since the position of an X-ray beam passing through each pixel on an image reconstruction plane can be predicted properly upon image reconstruction, the image reconstruction can be carried out accurately. In order to solve the above problem, there is provided an X-ray CT apparatus according to an eleventh aspect, wherein in the X-ray CT apparatus according to any of the first to ninth aspects, the operations of an X-ray data acquisition system about a scanning table z direction, a scanning table x direction, a scanning table y direction, a scanning gantry rotating section rotation-angle direction, a scanning gantry tilt angle direction, a scanning gantry x-direction angle direction, a scanning gantry y-direction angle direction and a scanning gantry z-direction angle direction of an X-ray data acquisition system are nonlinear control. In the X-ray CT apparatus according to the eleventh aspect, the operations of the scanning gantry corresponding to the X-ray data acquisition device, and the X-ray data acquisition device and scanning table lying thereinside are nonlinearly-controlled. Consequently, the discontinuity of acceleration can be eliminated and hence smoother operations can be taken. In particular, it is preferable to use the scanning table because it gives a softer operation to a subject placed thereon. Since the position of an X-ray beam passing through each pixel on an image reconstruction plane can properly be predicted upon image reconstruction even in this case, the proper image reconstruction can be carried out. In order to solve the above problems, there is provided an X-ray CT apparatus according to a twelfth aspect, wherein in the X-ray CT apparatus according to any of the first to eleventh aspects, the image reconstructing device performs three-dimensional image reconstruction as image reconstruction. In the X-ray CT apparatus according to the twelfth aspect, the three-dimensional image reconstruction is used to perform image reconstruction properly after the X-ray beam passing through each pixel on the image reconstruction plane is properly predicted upon image reconstruction in the first to eleventh aspects. Consequently, each X-ray projection data is backprojected on its corresponding proper position as viewed in the z direction and hence the photography or imaging of a tomographic image reduced in artifact and good in image quality can be realized. In order to solve the above problems, there is provided an X-ray CT apparatus according to a thirteenth aspect, wherein in the X-ray CT apparatus according to any of the first to twelfth aspects, the X-ray data acquisition device records at least one of an initial value, a completion value, an acceleration value, a deceleration value and a constant value with respect to at least one imaging condition of an X-ray tube voltage, an X-ray tube current, a scan velocity, an X-ray collimator aperture or open width and an X-ray collimator open position. In the X-ray CT apparatus according to the thirteenth aspect, even at executing portions of continuous operations, operations and changes, of an X-ray data acquisition system related to a mechanism system or an analog electric circuit, such as the X-ray tube voltage, X-ray tube current, scan velocity, X-ray collimator open width and X-ray collimator open position, the operations of the portions can be predicted and described with operation parameters when operated in X-ray data acquisition during photography in a manner similar to the prediction of the z-direction position of the scanning table, the prediction of the scanning gantry tilt angle and the like. Executing image reconstruction in consideration of the operations upon image reconstruction at this time enables proper image reconstruction. In order to solve the above problems, there is provided an X-ray CT apparatus according to a fourteenth aspect, wherein in the X-ray CT apparatus according to any of the first to thirteenth aspects, the X-ray data acquisition device adds at least one of an initial value, a completion value, an acceleration value, a deceleration value and a constant value to X-ray projection data and records the result of addition therein, with respect to at least one imaging condition of an X-ray tube voltage, an X-ray tube current, a scan velocity, a view data acquisition sampling frequency, the number of data acquisition channels and the number of data acquisition rows. In the X-ray CT apparatus according to the fourteenth aspect, the continuous operations, operations and changes of the X-ray data acquisition system can be described with their corresponding operation parameters, and the operation parameters can be recorded with being added to the X-ray projection data in the thirteenth aspect. Thus, image reconstruction can be executed properly by performing the image reconstruction in consideration of the operations upon the image reconstruction. According to the present invention, an X-ray CT apparatus can be realized which is capable of efficiently storing position information and photography or imaging information of an X-ray data acquisition system. The present invention will hereinafter be explained in further detail by embodiments illustrated in the figures. Incidentally, the present invention is not limited to or by the embodiments. [Apparatus Construction] FIG. 1 is a block diagram of an X-ray CT apparatus according to a first embodiment of the present invention. As shown in FIG. 1, the X-ray CT apparatus 100 according to the present embodiment is equipped with an operation console 1, an imaging or scanning table 10 and a scanning gantry 20. As shown in FIG. 1, the operation console 1 includes an input device 2 which receives an input from an operator, a central processing unit 3 which executes data processing such as a pre-process, an image reconstructing process, a post-process, etc. a data acquisition buffer 5 which acquires or collects X-ray detector data acquired by the scanning gantry 20, a monitor 6 which displays a tomographic image image-reconstructed from projection data obtained by pre-processing the X-ray detector data, and a memory or storage device 7 which stores programs, X-ray detector data, projection data and X-ray tomographic images therein. In the present embodiment, an input for imaging or photographing conditions is inputted from the input device 2 and stored in the storage device 7. An example of an imaging condition input screen is shown in FIG. 14. As shown in FIG. 1, the scanning table 10 includes a cradle 12 which inserts and draws a subject into and from a bore or aperture of the scanning gantry 20 with the subject placed thereon. Although not shown in the figure in particular, the cradle 12 is elevated and moved linearly on the scanning table 10 by a motor built in the scanning table 10. As shown in FIG. 1, the scanning gantry 20 includes an X-ray tube 21, an X-ray controller 22, a collimator 23, a beam forming X-ray filter 28, a multi-row X-ray detector 24, a DAS (Data Acquisition System) 25, a rotating section controller 26 which controls the X-ray tube 21 or the like that are mounted on a rotating section 15 so as to be rotated about a body axis of the subject, and a control controller 29 which swaps control signals or the like with the operation console 1 and the scanning table 10. Here, the beam forming X-ray filter 28 is configured so as to be thinnest in thickness as viewed in the direction of X rays directed to the center of rotation corresponding to the center of imaging, to increase in thickness toward its peripheral portion and to be able to further absorb the X rays as shown in FIG. 2. Therefore, in the present embodiment, the body surface of a subject whose sectional shape is nearly circular or elliptic can be less exposed to radiation. The scanning gantry 20 can be tiled about ±30° or so forward and rearward as viewed in the z direction by a scanning gantry tilt controller 27. The X-ray tube 21 and the multi-row X-ray detector 24 are rotated about the center of rotation IC as shown in FIG. 2. Assuming that the vertical direction is a y direction, the horizontal direction is an x direction and the travel direction of the table and cradle orthogonal to these is a z direction, the plane at which the X-ray tube 21 and the multi-row X-ray detector 24 are rotated, is an xy plane. The direction in which the cradle 12 is moved, corresponds to the z direction. FIGS. 2 and 3 are explanatory diagrams showing a geometrical arrangement or layout of the X-ray tube 21 and the multi-row X-ray detector 24 as viewed from the xy plane or yz plane. As shown in FIG. 2, the X-ray tube 21 generates an X-ray beam called a cone beam CB. Incidentally, when the direction of a central axis of the cone beam CB is parallel to the y direction, this is defined as a view angle 0°. As shown in FIG. 2, the multi-row X-ray detector 24 has X-ray detector rows arranged in plural form in the z direction and has, for example, X-ray detector rows corresponding to 256 rows. Each of the X-ray detector rows has X-ray detector channels corresponding to, for example, 1024 channels as viewed in a channel direction. As shown in FIG. 2, the X-ray beam emitted from an X-ray focal point of the X-ray tube 21 is spatially controlled in X-ray dosage by the beam forming X-ray filter 28 in such a manner that more X rays are radiated in the center of a reconstruction area or plane P and less X rays are radiated at a peripheral portion of the reconstruction area P. Thereafter, the X rays are absorbed by the subject that exists inside the reconstruction area P, and the X rays transmitted through the subject are acquired by the multi-row X-ray detector 24 as X-ray detector data. As shown in FIG. 3, the X-ray beam emitted from the X-ray focal point of the X-ray tube 21 is controlled in the direction of a slice thickness of a tomographic image by the X-ray collimator 23. That is, the X-ray beam is controlled in such a manner that the width of the X-ray beam becomes D at a central axis of rotation IC. Then, the X rays are absorbed into the subject existing in the vicinity of the central axis of rotation IC, and the X rays transmitted through the subject are acquired by the multi-row X-ray detector 24 as X-ray detector data. Thus, the projection data acquired by application of the X rays are outputted from the multi-row X-ray detector 24 to the DAS 25 and A/D converted by the DAS 25. Then, the data are inputted to the data acquisition buffer 5 via a slip ring 30. Thereafter, the data inputted to the data acquisition buffer 5 are processed by the central processing unit 3 in accordance with the corresponding program stored in the storage device 7, so that the data are image-reconstructed as a tomographic image. Afterwards, the tomographic image is displayed on a display screen of the monitor 6. Outline of Operations The outline of each operation of the X-ray CT apparatus 100 is shown below. FIG. 4 is a flow chart showing the outline of the operations of the X-ray CT apparatus according to the present embodiment. At Step P1, as shown in FIG. 4, the subject is first placed on the cradle 12 and its alignment is made. Here, a slice light center position of the scanning gantry 20 is aligned with a reference point of each region of the subject placed on the cradle 12. Next, at Step P2, scout image acquisition is performed as shown in FIG. 4. Here, a scout image is normally photographed at view angles of 0° and 90°. Incidentally, only a 90° scout image may be photographed or imaged as in the case of, for example, the head, depending upon each region. The details of the photographing of the scout image will be described later. Next, at Step P3, an imaging or photographing condition is set as shown in FIG. 4. Here, the imaging condition is normally set while the position and size of a tomographic image to be photographed are being displayed on a scout image. In this case, the whole X-ray dosage information corresponding to one helical scan, variable-pitch helical scan, helical shuttle scan, conventional scan (axial scan) or cine scan is displayed. When the number of rotations of a scanning gantry rotating section (an X-ray data acquisition system) or the set value of imaging (X-ray application) time is inputted upon the cine scan, X-ray dosage information corresponding to the inputted number of rotations in the area of interest of the subject or the time inputted is displayed. Upon setting of an imaging condition for the helical shuttle scan or the variable-pitch helical scan, operation parameters for performing z-direction operation control can be defined at the scanning table. These operation parameters are determined upon the setting of the imaging condition and sent to a scanning table control section to actually operate the scanning table. Then, these operation parameters are added to X-ray projection data. Upon image reconstruction, the position of an X-ray beam passing through each pixel on an image reconstruction plane is properly predicted in consideration of such an operation to perform proper three-dimensional image reconstruction. This image reconstruction will be explained in detail in FIG. 5 shown below. The three-dimensional image reconstruction will be described in detail in FIG. 7 shown below. The details of the operation parameters for the helical shuttle scan or the variable-pitch helical scan will also be explained later. Next, at Step P4, tomographic image photography is performed as shown in FIG. 4. The details of the tomographic image photography and the image reconstruction will be described later. Next, at Step P5, an image-reconstructed tomographic image is displayed as shown in FIG. 4. Next, at Step P6, a three-dimensional image display is performed as shown in FIG. 4. Here, a tomographic image photographed continuously in a z direction is used as a three-dimensional image and three-dimensionally image-displayed as shown in FIG. 15. As methods for the three-dimensional image display, may be mentioned, a volume rendering three-dimensional image display method, an MIP (Maximum Intensity Projection) image display method, an MPR (Multi Plain Reformat) image display method, a three-dimensional reprojection image display method, etc. They are used properly according to diagnostic applications. [Outline of Operations at Tomographic Image Photography and scout Image Photography] The outline of operations of the X-ray CT apparatus 100 at the execution of tomographic image photography (Step P4 in FIG. 4) and scout image photography (Step P2 in FIG. 4) upon will be shown below. FIG. 5 is a flow chart showing the outline of the operations for the tomographic image photography and scout image photography, of the X-ray CT apparatus 100 of the embodiment according to the present invention. At Step S1, data acquisition is first performed as shown in FIG. 5. When the data acquisition is carried out by a helical scan upon executing the tomographic image photography, the operation of rotating the X-ray tube 21 and the multi-row X-ray detector 24 about the subject and carrying out data acquisition of X-ray detector data while the cradle 12 placed on the imaging or scanning table 10 is being linearly moved, is performed. Upon the helical scan for acquiring or collecting the X-ray detector data, data acquisition in a constant-speed range is performed. Upon a variable-pitch helical scan or a helical shuttle scan, data acquisition is performed even at acceleration and deceleration in addition to the data acquisition in the constant-speed range. In this case, scanning table z-direction operation parameters predicted by the central processing unit 3 including imaging condition setting device are added to X-ray detector data D0 (view, j, i) indicated by a view angle view, a detector row number j and a channel number i. FIG. 17 is a diagram showing operations of the scanning table (cradle) at the helical shuttle scan. FIG. 17 describes the manner in which the scanning table is moved in the z direction. If parameters like, for example, cradle acceleration, cradle deceleration, a cradle stationary speed or velocity, a cradle initial position, a cradle stop position, a cradle acceleration end position and a cradle deceleration start position exist as shown in FIG. 17 here, then the operations of the scanning table can be described. If the scanning gantry and the scanning table corresponding to the X-ray data acquisition system can be moved with sufficient accuracy as predicted based on the parameters, it is then unnecessary to subject information about a scanning table z-direction coordinate position, a scanning table x-direction coordinate position, a scanning table y-direction coordinate position, a scanning gantry rotating section rotation-angle position, a scanning gantry tilt angle position, a scanning gantry x-direction coordinate position, a scanning gantry y-direction coordinate position, and a scanning gantry z-direction coordinate position set for each view to measurement, data acquisition and addition to X-ray projection data. Upon the conventional scan (axial scan) or the cine scan, the data acquisition system is rotated once or plural times while the cradle 12 placed on the scanning table 10 is being fixed to a given z-direction position, thereby to perform data acquisition of X-ray detector data. The cradle 12 is moved to the next z-direction position as needed and thereafter the data acquisition system is rotated once or plural times again to perform data acquisition of X-ray detector data. On the other hand, upon execution of the scout image photography, the operation of fixing the X-ray tube 21 and the multi-row X-ray detector 24 and performing data acquisition of X-ray detector data while the cradle 12 placed on the scanning table 10 is being linearly moved, is performed. Next, at Step S2, a pre-process is performed as shown in FIG. 5. Here, the pre-process is performed on the X-ray detector data D0 (view, j, i) to convert it into projection data. As shown in FIG. 6, the pre-process comprises an offset correction of Step S21, logarithmic translation of Step S22, an X-ray dosage correction of Step S23 and a sensitivity correction of Step S24. Upon the scout image photography, the pre-processed X-ray detector data is displayed with each of a pixel size in the channel direction and a pixel size in the z direction corresponding to the cradle linear moving direction being made coincident with a display pixel size of the monitor 6. Next, at Step S3, a beam hardening correction is performed as shown in FIG. 5. Here, the beam hardening correction is effected on the pre-processed projection data D1 (view, j, i). Assuming that upon the beam hardening correction of Step S3, projection data subjected to the sensitivity correction S24 at the pre-process S2 is defined as D1 (view, j, i) and data subsequent to the beam hardening correction of Step S3 is defined as D11 (view, j, i), the beam hardening correction is expressed in the form of, for example, a polynomial as given by the following expression (1). [1]D11(view,j,i)=D1(view,j,i)·(B0(j,i)+B1(j,i)·D1(view,j,i)+B2(j,i)·D1(view,j,i)2) Expression (1) Since, at this time, the independent beam hardening corrections can be carried out for every j row of the detectors, the difference between X-ray energy characteristics of the detectors placed for every row can be corrected if tube voltages of respective data acquisition systems are different on the imaging condition. Next, at Step S4, a z-filter convolution process is performed as shown in FIG. 5. Here, the z-filter convolution process for applying filters in the z direction (row direction) is effected on the projection data D11 (view, j, i) subjected to the beam hardening correction. That is, after the pre-process at each view angle and each data acquisition system, projection data of the multi-row X-ray detector D11 (view, j, i) (where i=1 to CH and j=1 to ROW) subjected to the beam hardening correction is multiplied in the row direction by filters in which such row-direction filter sizes as expressed in the following expressions (2) and (3) are five rows, for example. However, (the expression 3) is satisfied.(w1(i), w2(i), w3(i), w4(i), w5(i)) (Expression 2) [ 2 ] ∑ k = 1 5 ⁢ w k ⁡ ( i ) = 1 ( Expression ⁢ ⁢ 3 ) The corrected detector data D12 (view, j, i) is given as expressed in the following expression (4): [ 3 ] D ⁢ ⁢ 1 ⁢ ⁢ 2 ⁢ ⁢ ( view , j , i ) = ∑ k = 1 5 ⁢ ( D ⁢ ⁢ 11 ⁢ ( view , j + k - 3 , i ) · w k ⁡ ( j ) ) ( Expression ⁢ ⁢ 4 ) Incidentally, assuming that the maximum value of the channel is CH and the maximum value of the row is ROW, the following expressions (5) and (6) are established. [4]D11(view,−1,i)=D11(view,0,i)=D11(view,1,i) (Expression 5) [5]D11(viw,ROW,i)=D11(view,ROW+1,i)=D11(view,ROW+2,i) (Expression 6) When row-direction filter coefficients are changed for every channel, slice thicknesses can be controlled depending upon the distance from an image reconstruction center. In a tomographic image, its peripheral portion generally becomes thicker in slice thickness than the reconstruction center thereof. Therefore, the row-direction filter coefficients are changed at the central and peripheral portions, and the row-direction filter coefficients are widely changed in width in the neighborhood of a central channel and narrowly changed in width in the neighborhood of a peripheral channel, thereby making it possible to make the slice thickness uniform at both the peripheral portion and the image reconstruction center. Controlling the row-direction filter coefficients at the central and peripheral channels of the multi-row X-ray detector 24 in this way makes it possible to control the slice thickness at the central and peripheral portions. Thickening the slice thickness slightly by each row-direction filter yields extensive improvements in both artifact and noise. Thus, the degree of the improvement in artifact and the degree of the improvement in noise can also be controlled. That is, it is possible to control the quality of a three-dimensionally image-reconstructed tomographic image in the xy plane. In addition to above, a tomographic image having a thin slice thickness can also be realized by setting row-direction (z-direction) filter coefficients to deconvolution filters. Next, at Step S5, a reconstruction function convolution process is performed as shown in FIG. 5. That is, X-ray projection data subjected to the processes up to the (Expression 6) is subjected to Fourier transformation and multiplied by a reconstruction function, followed by being subjected to inverse Fourier transformation. Assuming that upon the reconstruction function convolution process S5, data subsequent to the z filter convolution process is defined as D12, data subsequent to the reconstruction function convolution process is defined as D13, and the convoluting reconstruction function is defined as Kernel(j), the reconstruction function convolution process is expressed as given by the following expression (7): [6]D13(view,j,i)=D12(view,j,i)Kernel(j) (Expression 7) That is, since the independent reconstruction function convolution process can be performed for every j row of the detectors, the reconstruction function Kernel (j) can correct differences in noise characteristic and resolution characteristic for every row. Next, at Step S6, a three-dimensional backprojection process is performed as shown in FIG. 5. Here, the three-dimensional backprojection process is effected on the projection data D13 (view, j, i) subjected to the reconstruction function convolution process to determine backprojection data D3 (x, y, z). An image-reconstructed image is three-dimensionally image-reconstructed on an xy plane corresponding to a plane orthogonal to the z axis. A reconstruction area or plane P to be shown below is assumed to be parallel to the xy plane. The three-dimensional backprojection process will be explained later referring to FIG. 5. Next, at Step S7, a post-process is performed as shown in FIG. 5. Here, the post-process including image filter convolution, CT value conversion and the like is effected on the backprojection data D3 (x, y, z) to obtain a CT or tomographic image D31 (x, y). Assuming that upon the image filter convolution process in the post-process, a tomographic image subsequent to the three-dimensional backprojection is defined as D31 (x, y, z), data subsequent to the image filter convolution is defined as D32 (x, y, z), and a two-dimensional image filter convolved on the xy plane corresponding to a tomographic image plane is defined as Filter(z), the following expression (8) is established. [7]D32(x,y,z)=D31(x,y,z)Filter(z) (Expression 8) That is, since the independent image filter convolution process can be performed for every j row of the detectors, it is possible to correct differences in noise characteristic and resolution characteristic for every row. An image space z-direction filter convolution process shown below may be performed after the two-dimensional image filter convolution process. The image space z-direction filter convolution process may be performed before the two-dimensional image filter convolution process. Further, a three-dimensional image filter convolution process may be performed to bring about such an effect as to share both the two-dimensional image filter convolution process and the image space z-direction filter convolution process. Assuming that upon the image space z-direction filter convolution process, a tomographic image subjected to the image space z-direction filter convolution process is defined as D33 (x, y, z), and a tomographic image subjected to the two-dimensional image filter convolution process is defined as D32 (x, y, z), the following relation (expression 9) is established. However, v(i) becomes such a coefficient row as expressed below (in expression 10) in the form of image space z-direction filter coefficients at which the width in the z direction is 21+1. [ 8 ] D ⁢ ⁢ 32 ⁢ ( x , y , z ) = ∑ i ⁢ = ⁢ - 1 ⁢ l ⁢ D ⁢ ⁢ 32 ⁢ ( x , y , z + i ) · v ⁡ ( i ) ( Expression ⁢ ⁢ 9 ) [ 9 ] v ⁡ ( - l ) , v ⁡ ( - l + 1 ) , … ⁢ ⁢ v ⁡ ( - 1 ) , v ⁡ ( 0 ) , v ⁡ ( 1 ) , … ⁢ ⁢ v ⁡ ( l - 1 ) , v ⁡ ( l ) ( Expression ⁢ ⁢ 10 ) Upon the helical scan, the image space filter coefficient v(i) may be an image space z-direction filter coefficient independent on a z-direction position. However, when the two-dimensional X-ray area detector 24 or the multi-row X-ray detector 24 broad in detector width as viewed in the z direction is used in particular, the image space z-direction filter coefficient v(i) can be subjected to detailed adjustments dependent on row positions of respective tomographic images upon execution of the conventional scan (axial scan) or the cine scan if the image space z-direction filter coefficient v(i) is given as each of image space z-direction filter coefficients dependent on the positions of the rows of the X-ray detector in the z direction. Therefore, this is further effective. The so-obtained tomographic images are displayed on the monitor 6. [Three-Dimensional Backprojection Process] The outline of the operation at the time that the three-dimensional backprojection process is carried out (S6 in FIG. 5) at the operations of the X-ray CT apparatus 100, is shown below. FIG. 7 is a flow chart showing the details of the three-dimensional backprojection process. In the present embodiment, an image to be image-reconstructed is three-dimensionally image-reconstructed on an xy plane corresponding to a plane orthogonal to the z axis. That is, the reconstruction area P is assumed to be parallel to the xy plane. At Step S61, attention is first given to one of all views (i.e., views corresponding to 360° or views corresponding to “180°+fan angles”) necessary for image reconstruction of a tomographic image as shown in FIG. 7. Projection data Dr corresponding to respective pixels in a reconstruction area P are extracted. Here, as shown in FIGS. 8(a) and 8(b), a square area of 512×512 pixels, which is parallel to the xy plane, is assumed to be a reconstruction area P. Further, a pixel row L0 parallel to an x axis of y=0, a pixel row L63 of y=63, a pixel row L127 of y=127, a pixel row L191 of y=191, a pixel row L255 of y=255, a pixel row L319 of y=319, a pixel row L383 of y=383, a pixel row L447 of y=447, and a pixel row L511 of y=511 are taken as rows. Thus, if projection data on lines T0 through T511 obtained by projecting these pixel rows L0 to L511 on the plane of the multi-row X-ray detector 24 in an X-ray penetration direction are extracted as shown in FIG. 9, then they result in projection data Dr (view, x, y) of the pixel rows L0 to L511. However, x and y correspond to respective pixels (x, y) of the tomographic image. The X-ray penetration direction is determined depending on geometrical positions of the X-ray focal point of the X-ray tube 21, the respective pixels and the multi-row X-ray detector 24. However, the operation of the scanning table is predicted for each view from the scanning table operation parameters added to the X-ray detector data. Further, the z coordinates z (view) of X-ray detector data D0 (view, j, i) are determined as the table linear movement z-direction position Ztable (view). Since the z-direction positions of the X-ray focal point and the multi-row X-ray detector in the data acquisition geometrical system are known even in the case of the X-ray detector data D0 (view, j, i) placed under acceleration and deceleration and during a constant velocity, the X-ray penetration direction can be accurately determined by prediction. Thus, three-dimensional image reconstruction for each pixel of a tomographic image can be carried out. Incidentally, when some of lines are placed out of the multi-row X-ray detector 24 as viewed in the channel direction as in the case of, for example, the line T0 obtained by projecting, for example, the pixel row L0 on the plane of the multi-row X-ray detector 24 in the X-ray penetration direction, the corresponding projection data Dr (view, x, y) is set to “0”. When it is placed outside the multi-row X-ray detector 24 as viewed in the z direction, the corresponding projection data Dr (view, x, y) is determined by extrapolation. Thus, as shown in FIG. 10, the projection data Dr (view, x, y) corresponding to the respective pixels of the reconstruction area P can be extracted. Next, at Step S62, as shown in FIG. 7, the projection data Dr (view, x, y) are multiplied by a cone beam reconstruction weight coefficient to create projection data D2 (view, x, y) as shown in FIG. 11. Now, the cone beam reconstruction weight function w (i, j) is as follows. Generally, when the angle which a linear line connecting the focal point of the X-ray tube 21 and a pixel g(x, y) on the reconstruction area P (xy plane) at view=βa forms with a center axis Bc of an X-ray beam is assumed to be γ and its opposite view is assumed to be view=βb in the case of fan beam image reconstruction, their relations are expressed as given by the following expression (11).βb=βa+180°−2γ (Expression 11) When the angles which the X-ray beam passing through the pixel g(x, y) on the reconstruction area P and its opposite X-ray beam form with the reconstruction plane P, are assumed to be αa and αb respectively, they are multiplied by cone beam reconstruction weight coefficients ωa and ωb dependant on these and added together to determine backprojection pixel data D2 (0, x, y). In this case, it is given as expressed in the following expression (12).D2(0,x,y)=ωa·D2(0,x,y)—a+ωb·D2(0,x,y)—B (Expression 12) where D2(0,x,y)_a shows backprojection data of view βa, and D2(0,x,y)_b shows backprojection data of view βb. Incidentally, the sum of the cone beam reconstruction weight coefficients corresponding to the beams opposite to each other is expressed like the following expression (13):ωa+ωb=1 (Expression 13) The above addition with multiplication of the cone beam reconstruction weight coefficients ωa and ωb enables a reduction in cone angle artifact. For example, ones determined by the following expressions can be used as the cone beam reconstruction weight coefficients ωa and ωb. Incidentally, ga indicates the weight coefficient of the view βa and gb indicates the weight coefficient of the view βb. When ½ of a fan beam angle is assumed to be γmax, the following relations are established as given by the following expressions (14) to (19): [10]ga=f(γmax,αa,βa) (Expression 14) [11]gb=f(γmax,αb,βb) (Expression 15) [12]xa=2·gaq/(gaq+gbq) (Expression 16) [13]xb=2·gbq/(gaq+gbq) (Expression 17) [14]wa=xa2·(3−2xa) (Expression 18) [15]wb=xb2·(3−2xb) (Expression 19) (For example, q=1). Assuming that max [ ] are defined as functions which adopt or take the maximum values as examples of ga and gb, for example, ga an gb are given as expressed in the following expressions (20) and (21). [16]ga=max[0, {(π/2+γmax)−\|βa\|}]·\|tan(αa))\| (Expression 20) [17]gb=max[0, {(π/2+γmax)−\|βb\|}]·\|tan(αb))\| (Expression 21) In the case of the fan beam image reconstruction, each pixel on the reconstruction area P is further multiplied by a distance coefficient. Assuming that the distance from the focal point of the X-ray tube 21 to each of the detector row j and channel i of the multi-row X-ray detector 24 corresponding to the projection data Dr is r0, and the distance from the focal point of the X-ray tube 21 to each pixel on the reconstruction area P corresponding to the projection data Dr is r1, the distance coefficient is given as (r1/r0)2. In the case of parallel beam image reconstruction, each pixel on the reconstruction area P may be multiplied by the cone beam reconstruction weight coefficient w (i, j) alone. Next, at Step S63, as shown in FIG. 7, the projection data D2 (view, x, y) is added to its corresponding backprojection data D3 (x, y) in association with each pixel. Described specifically, as shown in FIG. 12, the projection data D2 (view, x, y) is added to its corresponding backprojection data D3 (x, y) cleared in advance in association with each pixel. Next, it is determined at Step S64 as shown in FIG. 7 whether backprojection data D2 corresponding to all views necessary for image reconstruction are added. Here, when addition is not made (NO), Steps S61 through S63 are repeated with respect to all the views (i.e., views corresponding to 360° or views corresponding to “180°+fan angles”) necessary for image reconstruction of the tomographic image to obtain backprojection data D3 (x, y) as shown in FIG. 12. On the other hand, when addition is made (Yes), the present or actual process is terminated as shown in FIG. 7. Incidentally, the reconstruction area P may be set as a circular area whose diameter is 512 pixels, without setting it as the square area of 512×512 pixels as shown in FIGS. 13(a) and 13(b). [Operation Parameters] Embodiments about the details of the operation parameters for the X-ray CT apparatus 100 will be explained below. The operation parameters at the helical shuttle scan are shown in the first embodiment. FIG. 18 shows the z-direction operations of the scanning table at the helical shuttle scan. In FIG. 18, z0 indicates a scanning table initial position. z1 indicates a scanning table acceleration end position. z2 indicates a scanning table deceleration start position. z3 indicates a scanning table stop position. Here, as shown in FIG. 18, the scanning table is accelerated at a scanning table acceleration a1 in the range of z0 to z1. The scanning table is decelerated at a scanning table deceleration a2 in the range of z2 to z3. The scanning table is operated at a scanning table constant velocity v1 in the range of z1 to z2. In the present embodiment, the scanning table is controlled using z coordinates without using the time. This is because a scanning table control device for actually controlling the scanning table is easy to control it using the z coordinates of the scanning table rather than its control using the time. Of course, the control of the scanning table is made possible similarly even where it is controlled by the time without being controlled by the z coordinates. The helical shuttle scan is shuttled plural times as in the case of z0 to z3 to z0 to z3 as well as the above operations from z0 to z3. FIG. 18 shows the manner in which the helical shuttle scan is shuttled 1.5 times. One example illustrative of the operation parameters for the helical shuttle scan is shown in Table of FIG. 19. A second embodiment shows operation parameters at a variable-pitch helical scan. FIG. 20 shows z-direction operation parameters of the scanning table at the variable-pitch helical scan. Here, the operation parameters may be treated as another file associated with X-ray projection data or may be added to the X-ray projection data. Incidentally, FIG. 23 shows an example in which operation parameters are added to their corresponding X-ray projection data. In the X-ray projection data, an X-ray detector channel direction extends from a 1 channel to a CH channel, a row direction extends from a 1 row to a ROW row, the number of views per rotation is assumed to be N, and the number of rotations at which data acquisition is made at this time, is assumed to be M. Operation parameters are inserted into part of header information of X-ray projection data. In FIG. 20, z0 indicates a scanning table initial position. z1 indicates a scanning table acceleration end position. z2 indicates a scanning table deceleration start position. z3 indicates a scanning table deceleration end position. z4 indicates a scanning table acceleration start position. z5 indicates a scanning table acceleration end position. z6 indicates a scanning table deceleration start position. z7 indicates a scanning table deceleration end position. z8 indicates a scanning table deceleration start position. z9 indicates a scanning table stop position. Here, the scanning table is accelerated at a scanning table acceleration a1 in the range of z0 to z1. The scanning table is decelerated at a scanning table deceleration a2 in the range of z2 to z3. The scanning table is accelerated at a scanning table acceleration a3 in the range of z4 to z5. The scanning table is decelerated at a scanning table deceleration a4 in the range of z6 to z7. The scanning table is decelerated at a scanning table deceleration a5 in the range of z8 to z9. The scanning table is operated at a scanning table constant velocity v1 in the range of z1 to z2. The scanning table is operated at a scanning table constant velocity v2 in the range of z3 to z4. The scanning table is operated at a scanning table constant velocity v1 in the range of z5 to z6. The scanning table is operated at a scanning table constant velocity v3 in the range of z7 to z8. A third embodiment shows operation parameters at a scan reduced in needless exposure at the time that an X-ray data acquisition system lying in a scanning gantry is tilted during a helical scan. FIG. 21 shows the outline of the operation of tilting the X-ray data acquisition system in such a manner that X-ray needless exposure is reduced in the embodiment for the helical scan thereby to acquire or collect data. FIG. 22 shows operation parameters for tilting the X-ray data acquisition system in such a manner that the X-ray needless exposure is reduced in the embodiment for the helical scan, thereby to control tilt angles for tilting the data acquisition system upon execution of the scan. Here, −θ0 indicates an initial value of a tilt angle of the X-ray data acquisition system. A z-direction table coordinate position at this time is z0. −θ1 indicates an acceleration end position of the tilt angle of the X-ray data acquisition system. A z-direction table coordinate position at this time is z4. θ2 indicates a deceleration start position of the tilt angle of the X-ray data acquisition system. A z-direction table coordinate position at this time is z5. +θ0 indicates a stop position of the tile angle of the X-ray data acquisition system. A z-direction table coordinate position at this time is z3. The tilt angle of the X-ray data acquisition system is accelerated in the range of [−θ0, −θ1] as shown in FIG. 22. Acceleration A at this time changes nonlinearly as expressed in the following expression (22): [18]A=a1·cos(b1·t)+c1 (Expression 22) The tilt angle of the X-ray data acquisition system is decelerated in the range of [θ2, +θ0]. Deceleration B at this time changes nonlinearly as expressed in the following expression (23): [19]B=a2·cos(b2·t)+c2 (Expression 23) The X-ray data acquisition system is operated at a constant angular velocity ω1 in the range of [−θ1, θ2]. In this case, control on the tilt of the data acquisition system is set to be carried out by a cos curve (cosine curve) in advance, whereby parameters for an accelerating operation are simplified as (a1, b1 and c1) and parameters for a decelerating operation are simplified as (a2, b2 and c2). And they can also be stored as operation parameters. Although the operation parameters for the tilt angles of the X-ray data acquisition system have been described above, the z-direction operation parameters of the scanning table may be made similar to the first and second embodiments. As described above, the X-ray CT apparatus 100 according to the present embodiment includes the scanning table 10 which moves the cradle 12 with the subject placed thereon within imaging space, the scanning gantry 20 which applies X rays to the subject placed on the cradle 12 moved within the imaging space and performs the scan for detecting the X-rays transmitted through the subject to thereby obtain projection data, the central processing unit 3 which controls the operations of the scanning table 10 and the scanning gantry 20 to execute the scan thereby to acquire plural projection data in time-series order and image-reconstructs by calculation, a tomographic image of the subject from the projection data obtained by execution of the scan, and the monitor 6 which displays the tomographic image image-reconstructed by the central processing unit 3 on its display screen (see FIG. 1). Here, the scanning table 10 moves the cradle 12 along the body axial direction (z direction) of the subject placed on the cradle 12 on the basis of each control signal outputted from the central processing unit 3. The scanning gantry 20 includes the X-ray tube 21 which applies X rays from the periphery of the subject moved by the scanning table 10 to the subject within the imaging space so as to rotate with the direction extending along the z direction as the axis, and the multi-row X-ray detector 24 which detects the X rays radiated from the X-ray tube 21 and transmitted through the subject. The respective parts are controlled based on the control signals outputted from the central processing unit 3. The X-ray tube 21 applies the X rays onto the subject such that they are brought to a cone shape spread in the channel direction extending along the direction of rotation of the X-ray tube rotated around the subject and the row direction extending along the rotational-axis direction of its rotation. In the multi-row X-ray detector 24, a plurality of X-ray detectors for detecting the X rays radiated from the X-ray tube 21 and transmitted through the subject are arranged in matrix form so as to correspond to the channel and row directions (see FIGS. 2 and 3). Upon photographing the subject by using the X-ray CT apparatus 100, the condition for performing the scan about the subject is first inputted to the input device 2 by the operator. Thereafter, the central processing unit 3 sets parameters for operating the scanning gantry 20 and parameters for moving the cradle 12 with the subject placed thereon to the scanning table 10 as viewed in the z direction, based on the condition inputted to the input device 2. For example, parameters are set such that the helical shuttle scan is carried out as described above. Described specifically, the initial position of the cradle 12 at the time that the execution of the scan is started, acceleration at which the cradle 12 is accelerated and moved from the initial position, an acceleration end position at which the acceleration and movement of the cradle is terminated, the velocity at which the cradle 12 is moved constant from the acceleration end position, a deceleration start position at which the cradle 12 moved constant is decelerated, deceleration at which the cradle 12 is decelerated and moved from the deceleration start position, a stop position where the moved cradle 12 is stopped, the timing at which projection data is obtained at the scanning gantry 2, are respectively set as parameters. Next, the central processing unit 3 controls the operations of the scanning gantry 2 and the scanning table 10, based on the set parameters to execute a scan. For example, the helical shuttle scan is carried out based on the parameters set as described above. At this time, the storage device 7 stores or processes a plurality of projection data obtained in a time sequence order by execution of the scan, and position data about the positions of the cradle 12 moved in the z direction when the projection data are respectively obtained, therein in association with one another upon storage of X-ray projection data or an image reconstruction process. Here, the central processing unit 3 calculates position data about the respective positions of the cradle 12 moved in the row direction z when the projection data are respectively obtained, on the basis of both the parameters for moving the scanning gantry 20 and the parameters for moving the cradle 12 with the subject placed thereon to the scanning table 10. Thereafter, the calculated positions data and the projection data obtained by execution of the scan are respectively stored in the storage device 7 in association with one another. That is, in the present embodiment, the position data of the cradle 12 obtained by operation by device of the central processing unit 3 are stored in association with the corresponding projection data without storing the position data of the cradle 12 obtained by measurement by device of hardware such as a rotary encoder, a linear encoder or the like in association with the projection data. Next, the central processing unit 3 image-reconstructs a tomographic image of the subject on the basis of the respective X-ray projection data and the position data stored in association with the X-ray projection data. And the monitor 6 displays the tomographic on its display screen. Thus, in the present embodiment, the operator sets the imaging condition to thereby determine the operations of the X-ray data acquisition system and the scanning table or the cradle. That is, as the operations of the X-ray data acquisition system and the scanning table with the subject placed thereon, a scanning table z-direction coordinate position, a scanning table x-direction coordinate position, a scanning table y-direction coordinate position, a scanning gantry rotating section rotation-angle position, a scanning gantry tilt angle position, a scanning gantry x-direction coordinate position, a scanning gantry y-direction coordinate position, and a scanning gantry z-direction coordinate position are predicted upon setting of the imaging condition. Since the X-ray data acquisition system and the scanning table are normally feedback-controlled with an accuracy of 0.1 mm or less, they do not deviate vastly from their predicted values. Therefore, in the present embodiment, the operations of the X-ray data acquisition system and the scanning table can be reproduced by describing the predicted operations of the X-ray data acquisition system and the scanning table by several parameters in advance and recording the parameters. Thus, in the present embodiment, the X-ray CT apparatus having the two-dimensional X-ray area detector of matrix structure typified by the multi-row X-ray detector or flat-panel X-ray detector is capable of efficiently storing position information and photography information of the X-ray data acquisition system at the conventional scan (axial scan), the cine scan, the helical scan, the variable-pitch helical scan or the helical shuttle scan. Incidentally, the image reconstructing method according to the present embodiment may be a three-dimensional image reconstructing method based on a conventional known Feldkamp method. Further, another three-dimensional image reconstructing method may be adopted. Alternatively, two-dimensional image reconstruction may be used. Although the present embodiment has described the operations in the z direction alone as the operations of the scanning table, similar effects can be brought about even in the case where the scanning table is operated in the x and y directions. Although the present embodiment has described the tilt operations as the operations of the X-ray data acquisition system in the scanning gantry, similar effects can be brought about even in the case where the scanning gantry is operated in the x, y and z directions. Although the first or second embodiment has described the case in which the scanning gantry 20 is not tilted, similar effects can be brought about even in the case of a so-called tilt scan in which the scanning gantry 20 is tiled. Although the present embodiment has described the case in which the X-ray projection data acquisition is not synchronized with the biological signal, similar effects can be brought about even when synchronization with a biological signal, particularly, a cardiac signal is taken. Although the present embodiment has described the X-ray CT apparatus having the two-dimensional X-ray area detector of the matrix structure, which is typified by the multi-row X-ray detector or the flat panel X-ray detector, similar effects can be brought about even in the case of an X-ray CT apparatus having a one-row X-ray detector. In the present embodiment, the row-direction (z-direction) filters different in coefficient every row are convolved to adjust variations in image quality, provide a uniform slice thickness for each row, prevent the occurrence of artifacts and realize the quality of an image low in noise. Although various z-direction filter coefficients are considered therefor, any can bring about similar effects. Although the present embodiment has been described on the basis of the medical X-ray CT apparatus, it can be applied even to an X-ray CT-PET apparatus, an X-ray CT-SPEC apparatus and the like combined with an industrial X-ray CT apparatus or other apparatus.

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