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048790885	abstract	Nuclear fuel rods are checked for the presence of water in their interior by injecting bursts of ultrasound radially into the wall of each tube, producing echoing back and forth between the inner and outer surfaces of the tube. The rate of decay of this echoing indicates whether or not water is present.
	description	This application claims the benefit of priority of Japanese Patent Application No. 2003-360760 filed on Oct. 21, 2003, and the disclosure of which is incorporated herein by its entirely. 1) Field of the Invention The present invention relates to a scanning microscope system including a scanning microscope incorporated with an optical microscope, and, especially, to a scanning microscope system in which observations are made with a scanning microscope after a region to be observed with the scanning microscope is automatically selected with an optical microscope beforehand. 2) Description of the Related Art An observation technique that carries out time series observation of neurons widely dispersed in a sample is used for analysis of neurons to date. Specifically, the neurons to be observed are extracted among hundreds of neurons dispersed in the sample, observations and experiments are performed as the time passes, and the analysis is performed, based on statistical data obtained through the observations and the experiments. Moreover, there is performed a multipoint time lapse system such that the regions in which the neurons are dispersed in the sample are observed in time series while the regions are moved with a motor-driven stage. According to a scanning optical microscope disclosed in Japanese Patent No. 2824462, a sample multiple-stained with different fluorescent dyes is excited at different wavelengths, and a plurality of emitted fluoresces is detected with a photo detector. According to a disk-rotation confocal microscope is disclosed in Japanese Patent Application Laid-Open NO. 2003-5078, a disk provided with a transmission portion such as a slit pattern is inserted into an optical path in a common microscope, and rotation of the disk results in a confocal effect. Since neurons are dispersed in a sample when the neurons are observed with a scanning microscope conventionally, it is required to take from a few days to about one week before positions of the neurons are specified, a laser beam source suitable for an observation object is selected, and images of the neurons are acquired. Moreover, since, in the scanning microscope, regions in which there are the neurons are screened by laser beam, the fluorescence intensity of some neurons decreases before they are observed. Such observation is carried out repeatedly for a long time. Accordingly, the main body of the microscope is heated by, for example, the laser beam source of the microscope, thereby being deflected. Since a motor-driven stage is also repeatedly moved during the repeated observation, errors by movements of the motor-driven stage are accumulated, and therefore shifts of observation positions are caused. It is an object of the present invention to at least solve the problems in the conventional technology. A scanning microscope system according to one aspect of the present invention includes an optical microscope observation unit that irradiates a sample with excitation light, and forms an optical image from fluorescence emitted from the sample. The system also includes a scanning map creator and a flying spot scanning observation unit. The scanning map creator creates a scanning map indicating a scanning region in which a substance to be scanned exists in the sample, based on brightness of pixels of the optical image. The flying spot scanning observation unit scans the scanning region of the sample with laser beam, and forms a scanning image based on fluorescence emitted from the sample. The other objects, features, and advantages of the present invention are specifically set forth in or will become apparent from the following detailed description of the invention when read in conjunction with the accompanying drawings. Exemplary embodiments of the present invention will now be explained in detail below with reference to the accompanying drawings. The invention is not limited to these embodiments, or to observation of biological specimens such as cells in a biological, or medical field, but can be also applied to other uses such as inspection of industrial products. In a first embodiment, an image is acquired with an optical microscope, a region in which a pixel group forming the acquired image has great brightness is registered as a region in which there is a substance to be observed, and the registered region is observed with a scanning microscope. FIG. 1 is a block diagram that depicts a configuration of a scanning microscope system according to the first embodiment. In the scanning microscope system 1, an optical path in a microscope main body 2 is connected to an optical microscope observation unit 4 and a flying spot scanning observation unit 5 through an optical path switch 3, and the microscope main body 2, the optical microscope observation unit 4, and the flying spot scanning observation unit 5 are connected to a computer 6 including a monitor 8 in order to control the system. The computer 6 includes a main controller 61, a microscope-main-body controller 62 an optical-path-switch controller 63, an optical-microscope-observation unit controller 64, a scanning map creator 66, a scanning map searcher 67, a flying-spot-scanning-observation unit controller 68, an A/D (analog-digital) input channel (CH) 71 connected to the optical microscope observation unit 4, an A/D input CH 72 connected to the flying spot scanning observation unit 5, a memory 73, an image processor 74, and an image forming unit 83. The main controller 61 controls the microscope-main-body controller 62, the optical-path-switch controller 63, the optical-microscope-observation unit controller 64, the scanning map creator 66, the scanning map searcher 67, the flying-spot-scanning-observation unit controller 68, the image processor 74, and the image forming unit 83. The microscope main body 2 includes a reflecting mirror 21, a revolver 22, an object lens 23, and an motor-driven XY stage 24, and is controlled by the microscope-main-body controller 62 in the computer 6. A sample 25 is mounted on the motor-driven XY stage 24. FIG. 2A is a top view of the sample 25 on the motor-driven XY stage 24. FIG. 2B is a side view of the sample 25. The sample 25 has a thickness of L in the Z direction, and several hundreds of neurons 26 to be observed are scattered in the sample 25. The neurons 26 have been stained with fluorescent dyes beforehand according to observation objects. When an image of the sample 25 is acquired with the optical microscope observation unit 4, it is difficult to acquire only a sharp image at the focus position, and the image acquired with the optical microscope observation unit 4 includes component images, which are out of focus, at positions other than the focus position, because a focus depth is corresponding to the magnification (numerical aperture) of the object lens 23. The sample 25 mounted on the motor-driven XY stage 24 is irradiated with excitation light entered from the optical microscope observation unit 4, or the flying spot scanning observation unit 5 through the reflecting mirror 21, and the object lens 23 installed in the revolver 22. When the light is applied to the sample 25, the neuron 26 in the sample 25 to be observed emits fluorescence. The fluorescence emitted from the sample 25 is guided to the optical microscope observation unit 4 or the flying spot scanning observation unit 5 in the backward direction along the optical path, along which the light has entered, that is, through the object lens 23, the reflecting mirror 21, and the optical path switch 3. The optical path switch 3 includes a mirror 31 that can be inserted into the optical path, and the optical-path-switch controller 63 in the computer 6 controls the insertion of the mirror 31. When the mirror 31 is inserted onto the optical path in the optical path switch 3, the optical path in the microscope main body 2 is connected to the flying spot scanning observation unit 5. When the mirror 31 is removed from the path, the optical path in the microscope main body 2 is connected to the optical microscope observation unit 4. The microscope-main-body controller 62 electrically controls a focusing unit such as the revolver 22 and the motor-driven XY stage 24 in the microscope main body 2 in order to adjust the focus position. For example, the object lens 23 installed in the revolver 22 is moved in the Z direction for focusing in the Z direction, and the motor-driven XY stage 24 is done in the X and Y directions to acquire an image within a range specified by an observer. When the image is acquired with a CCD camera 44 in the optical microscope observation unit 4, and with the flying spot scanning observation unit 5, an image with approximately the same size is acquired with the object lens 23 with the same magnification. The optical microscope observation unit 4 includes a halogen lamp source 41, a excitation filter 42, a dichroic mirror 43, and a CCD camera 44, and is controlled by the optical-microscope-observation unit controller 64 in the computer 6. The halogen lamp source 41 is a white light source. The light source of the optical-microscope-observation unit controller 64 is not limited to a halogen lamp, and may use a white light source such as a xenon lamp. The excitation filter 42 extracts light with a wavelength exciting fluorescence, with which the sample 25 is stained, from white light emitted from the halogen lamp source 41. The light extracted with the excitation filter 42 enters the optical path switch 3 through the dichroic mirror 43. The CCD camera 44 receives the fluorescence and the reflection light emitted from the sample 25, which are passing through the dichroic mirror 43. The CCD camera 44 is a photoelectric converter that accumulates charges according to the amount of the light emitted from the sample 25. The A/D input CH 71 converts the charges accumulated in the CCD camera 44 into a digital electric signal, and each block of optical image information 76 in the memory 73 sequentially stores the charges. FIG. 3 is an exemplary view that depicts the optical image information 76, and one enlarged block forming the optical image information 76. One block of the optical image information 76 stores the image formed with the CCD camera 44. When images of the sample 25 are formed one by one from one end to the other while controlling the motor-driven XY stage 24, the extensive optical image information 76 as shown in FIG. 3 can be acquired. The size of each block of the optical image information 76 is an image size of X1Y1, which is acquired by the optical microscope observation unit 4 or the flying spot scanning observation unit 5. In the enlarged view of a block as shown in FIG. 3, pixels with high brightness are represented by open circle marks, and those with low one are done by solid circle marks. Portions with neurons 26 are schematically denoted by the open circle marks, because the brightness is high in the portions with the neurons. On the other hand, portions with no neurons 26 are denoted by the solid circle marks in a schematic manner, because the brightness is low in the portions with no neurons. The memory 73 stores the optical image information 76, a scanning map 77 created from the optical image information 76, scanning image information 79, a brightness and voltage conversion table 81, and an exposure time and voltage conversion table 82. The image processor 74 constructs an image for display on the monitor 8, using the optical image information 76, or the scanning image information 79 in the memory 73, which are acquired through the main controller 61. The optical image information 76 includes image data for each block, which is acquired from the optical microscope observation unit 4 through the A/D input CH 71, and integration of pieces of the image data for each block, and the scanning image information 79 is image data formed by the image forming unit 83, based on (1) output signals output from photomultipliers 56 in the flying spot scanning observation unit 5 through the A/D input CH 72, and (2) the scanning position information from the scanner 53. The brightness and voltage conversion table 81 sets the voltage of the photomultipliers 56 in the flying spot scanning observation unit 5, using the optical image information 76 acquired with the optical microscope observation unit 4. The exposure time and voltage conversion table 82 is used for setting the voltage of the photomultipliers 56 in the flying spot scanning observation unit 5, using exposure time of the CCD camera 44 when an image is acquired, using the automatic exposure control function of the CCD camera 44. The scanning map creator 66 counts, through the main controller 61, the number of pixels with brightness higher than a threshold, for example, the number of pixels represented by open circle marks among pixels in blocks in the optical image information 76 in the memory 73. If the number of pixels with brightness higher than a threshold is equal to or larger than a predetermined number in a block, the block is set as a block with neurons 26. That is, the scanning map creator 66 screens blocks with the neurons 26 to create the scanning map 77 that memorizes information on positions of the blocks. FIG. 4A is a view that depicts a step of screening by the scanning map creator 66. FIG. 4B is a view that depicts diagonally shaded blocks having the neurons 26 to be observed. FIG. 4C is a view that depicts one example of the scanning map 77. The scanning map creator 66 screens blocks as shown in FIG. 4A, using the CCD camera 44 in the optical microscope observation unit 4, to acquire the optical image information 76 for each block from the right to the left one by one in the X direction of the optical image information 76 and to determine whether the number of pixels with brightness equal to or higher than the threshold is equal to or larger than the predetermined number in the block with the acquired optical image information 76. When the process is completed for one horizontal row in the Y direction, the process proceeds to that of the subsequent row, which is just under the previous row by one in the Y direction, to repeat the similar screening. The scanning map creator 66 writes “1” into the positions of diagonally shaded blocks, in which the number of pixels with brightness equal to or higher than the threshold is equal to or larger than the predetermined number and it can be assumed as shown, for example, in FIG. 4B that there are the neurons 26 to be observed, and “0” into those of blocks in which the number of pixels with brightness equal to or higher than the threshold is smaller than the predetermined number. The scanning map 77 shown in FIG. 4C is created as described above. Thus, the blocks in which “1” is written in the scanning map 77 are registered in such a way that further detailed images are acquired with the flying spot scanning observation unit 5. Moreover, when it is confirmed that the brightness at the edge of a block is equal to or higher than the threshold, “1” is also substituted into the position of another block next to the block in the scanning map 77, based on link information for the pixels, and the another block is registered in such a way that the another block acquires an image with the flying spot scanning observation unit 5, because there are some cases in which one block that can be acquired in the flying spot scanning observation unit 5 is too small to put the whole axon of a neuron 26 therein. Under control of the optical-path-switch controller 63, the mirror 31 is inserted into the optical path of the optical path switch 3, and the optical path in the microscope main body 2 is connected to the flying spot scanning observation unit 5. Thereafter, the scanning map searcher 67 automatically searches for blocks in which “1” is written in the scanning map 77, and acquires detailed images of the blocks, in which “1” is written, through the flying spot scanning observation unit 5. The flying spot scanning observation unit 5 includes a laser beam source 51, a dichroic mirror 52 for switching excitation wavelengths, a scanner 53, a plurality of dichroic mirrors 54 that perform measurement, and a plurality of sets of barrier filters 55 and photomultipliers 56 which are connected to the dichroic mirror 54 one by one. Moreover, the flying-spot-scanning-observation unit controller 68 in the computer 6 controls the unit 5. The flying-spot-scanning-observation unit controller 68 controls the laser beam source 51 so that the source 51 emits laser beam with the same wavelength as that of the excitation filter 42 in the optical microscope observation unit 4. The dichroic mirror 52 reflects laser beam from the laser beam source 51 so that the light enters the scanner 53. The scanner 53 includes two not-shown galvanometer mirrors that perform X-direction scanning and Y-direction scanning. The scanner 53 scans a sample in the X and Y directions with light from the laser beam source 51 according to scanning control signals from the computer 6, and outputs end-of-scanning signals to the computer 6 whenever scanning one line in the X direction. The scanner 53 is provided so that the light that scans a sample in the X and Y directions is applied to the sample 25 in the microscope main body 2 as spot light through the optical path switch 3. Fluorescence or reflection light emitted from the sample 25, based on irradiation of spot light, is returned to the flying spot scanning observation unit 5 through the optical path switch 3. The light returned to the flying spot scanning observation unit 5 passes through the dichroic mirror 52, and the photoelectric converters such as the photomultipliers 56 receive only light with wavelengths limited with a measurement-wavelength switch such as the dichroic mirror 54, which perform measurement, and the barrier filters 55 as observers desire. The photoelectric converter such as the photomultipliers 56 accumulates charges according to the amount of the light, the A/D input CH 72 converts the charges to a digital electric signal, the image forming unit 83 forms a two-dimensional image, based on the output signals from the photomultipliers 56 and the scanning position information from the scanner 53, and the two-dimensional image is stored in the memory 73 as the scanning image information 79. The image processor 74, as required, constructs an image, based on the scanning image information 79 through the main controller 61, for display on the monitor 8. Processing of creating the scanning map 77 will be explained below. FIG. 5 is a flow chart that depicts processing that creates the scanning map 77. For example, at start of observation of the neurons 26 the main controller 61 activates the processing creating the scanning map 77, using commands and the like that observers input. When the processing that creates the scanning map 77 is started, in the first place, the optical-path-switch controller 63 removes the mirror 31 in the optical path switch 3, and the optical path in the microscope main body 2 is connected to the optical microscope observation unit 4 (step S501). Under control of the optical-microscope-observation unit controller 64, excitation light is extracted with the excitation filter 42 from the white light emitted from the halogen lamp source 41 in the optical microscope observation unit 4, and the light enters the microscope main body 2 from the optical path switch 3 through the dichroic mirror 43. The microscope-main-body controller 62 controls the excitation light that enters the microscope main body 2 so that the light irradiates the sample 25 mounted on the motor-driven XY stage 24 through the reflecting mirror 21 in the microscope main body 2, and the object lens 23 installed in the revolver 22 (step S502). When the sample 25 is irradiated with the excitation light, the neurons 26 to be observed in the sample 25 emit fluorescence. The CCD camera 44 receives the light which the sample 25 emits and passes through the dichroic mirror 43 (step S503). The A/D input CH 71 converts the charges, which the CCD camera 44 accumulates according to the amount of the light, into a digital electric signal, and one block in the optical image information 76 stores the signal (step S504). When the processing is not completed for all blocks (NO at step S505), the processing returns to step S502 to acquire the image of the subsequent block in the optical image information 76. When the processing of image acquisition is completed for all blocks (YES at step S505), the scanning map creator 66 counts the number of pixels with brightness equal to or higher than the threshold among pixels in the image in a block (step S506). When the number of pixels with brightness equal to or higher than the threshold in the block is equal to or larger than the predetermined number after the counting (YES at step S507), “1” is substituted into the position of the corresponding block in the scanning map 77, and the corresponding block is registered in such a way that the flying spot scanning observation unit 5 observes there (step S508). When the number of pixels with brightness equal to or higher than the threshold is smaller than the predetermined number (NO at step S507), “0” is substituted into the position of the corresponding block in the scanning map 77 (step S509). When the neurons 26 are substances to be observed and the brightness is confirmed at the edge of a block, “1” may be also substituted into the position of another block next to the corresponding block in the scanning map 77, based on link information for the pixels, in such a way that the flying spot scanning observation unit 5 observes there and the above blocks may be registered in such a way that the flying spot scanning observation unit 5 observes there. When the processing is not completed for all blocks (NO at step S510), the subsequent block is extracted (step S511), and the processing returns to step S506 to repeat the similar processing for the subsequent block. When the processing is completed for all blocks (YES at step S510), the processing of creating the scanning map 77 is completed. FIG. 6 is a flow chart that depicts variation processing of creating the scanning map 77. Processing from step S601 to step S604 is the same as the processing from step S501 to step S504 through which the image of one block in the optical image information 76 is acquired, and processing from step S605 to step S610 is the same as the processing from step S506 to step S511 through which it is determined whether the scanning map 77 registers one block, which acquired the image, in the optical image information 76. The second processing of creating the scanning map 77 determines whether blocks which continuously acquired images after acquiring the image of one block of the optical image information 76 are registered in the scanning map 77. The scanning map 77 may be created through processing according to either of FIG. 5 or FIG. 6. When the flying spot scanning observation unit 5 observes the neurons 26 in time series, processing of searching the scanning map 77 is started at intervals over time set with a timer and the like at completion of creating the scanning map 77. Subsequently, processing of searching the scanning map 77 is explained. FIG. 7 is a flow chart that depicts processing of searching the scanning map 77. For example, when the neurons 26 are observed in time series, the main controller 61 starts processing of searching the scanning map 77 at intervals over time set with a timer and the like. In the first place, under control of the optical-path-switch controller 63, the mirror 31 in the optical path switch 3 is inserted, and the optical path in the microscope main body 2 is connected to the flying spot scanning observation unit 5 (step S701). Then, the scanning map 77 searcher 67 sequentially searches the scanning map 77. If “1” is substituted into the position of the corresponding block in the scanning map 77 (YES at step S702), laser beam with the same wavelength as the excitation wavelength, which is emitted from the laser beam source 51 in the flying spot scanning observation unit 5 with the scanning optical-microscope-observation unit controller 64 and extracted with the excitation filter 42 in the optical microscope observation unit 4, irradiates the sample 25 on the microscope main body 2 as spot light through the optical path switch 3 under scanning in the X and Y directions with the scanner 53 (step S703). The fluorescence or the reflection light emitted from the sample 25 that is irradiation with the spot light returns to the flying spot scanning observation unit 5 through the optical path switch 3. The light returned to the flying spot scanning observation unit 5 passes through the dichroic mirror 52, and the photoelectric converter such as the photomultipliers 56 receives the light with wavelengths limited with a measurement-wavelength switch such as the dichroic mirror 54, which perform measurement, and the barrier filters 55 as observers desire (step S704). The A/D input CH 72 converts the charges, which the photomultipliers 56 accumulates according to the amount of the light, into a digital electric signal, the image forming unit 83 forms a two-dimensional image, based on the output signal from the photomultipliers 56 and the scanning position information from the scanner 53, and the memory 73 stores the image as the scanning image information 79 (step S705). The image processor 74 constructs an image with the scanning image information 79 through the main controller 61, and displays the image on the monitor 8 (step S706). If the processing is not completed for all blocks (NO at step S707), the subsequent block in the scanning map 77 is selected (step S708), and the processing returns to step S702 to repeat the similar processing. If the processing is completed for all blocks (YES at step S707), processing of searching the scanning map 77 is completed, and is started again at intervals over time set with a timer and the like. The first embodiment has a configuration in which, as shown at step S504 and step S604, one block in the optical image information 76 stores charges which the CCD camera 44 accumulates according to the amount of the light, but the size of the image formed with the CCD camera 44 is not limited to one block in the optical image information 76. A configuration in which an image for a plurality of blocks, for example, about three or four blocks is formed, the image is stored as an integrated one in the optical image information 76, and each block is screened may be applied. As explained above in detail, since the first embodiment has a configuration in which, among blocks in the optical image information 76 acquired with the optical microscope observation unit 4, blocks in which the number of pixels with brightness equal to or higher than the threshold is equal to or larger than the predetermined number are registered, and the scanning image information 79 for the blocks registered in the scanning map 77 is automatically acquired, using a timer and the like, it is possible to automatically observe neurons 26, which agree to an observation object, in detail with the flying spot scanning observation unit 5, it is possible to automatically observe neurons 26, which agree to an observation object, in detail with the flying spot scanning observation unit 5, though there are several hundreds of neurons 26 scattered on a sample to be observed. Accordingly, the load of observers can be reduced to shorten time required to observe. Moreover, as white light such as halogen light is used at screening with the optical microscope observation unit 4, less fading in fluorescence can be caused by screening, and sharp scanning image information 79 can be obtained. Optical image information 76 is acquired beforehand, using the CCD camera 44 in the optical microscope observation unit 4, in the first embodiment. Thereafter, the optical image information 76 acquired with the optical microscope observation unit 4 can be used when conditions are set in order to acquire the scanning image information 79, using the flying spot scanning observation unit 5. That is, if the voltage of the photoelectric converters such as the photomultipliers 56 in the flying spot scanning observation unit 5 is set, based on the optical image information 76 acquired beforehand with the optical microscope observation unit 4, or conditions by which images are formed, the best voltage of the photomultipliers 56 can be set. FIG. 8A is a view that depicts an example of the brightness and voltage conversion table 81. When the voltage of the photomultipliers 56 as the vertical axis is obtained from the brightness of the optical image information 76 acquired with the optical microscope observation unit 4 as the horizontal axis, using the brightness and voltage conversion table 81, the best voltage to drive the photomultipliers 56 can be automatically set when an image is acquired in the flying spot scanning observation unit 5. At this time, in order to use the same conditions under which an image for the optical image information 76 is acquired, the optical image information 76 is acquired, assuming that the charge accumulation time of the CCD camera 44 is constant. Similarly, the voltage of the photomultipliers 56 in the flying spot scanning observation unit 5 is set, using automatic setting function, which the CCD camera 44 has, to determine exposure time of each block. FIG. 8B is a view that depicts an example of the exposure time and voltage conversion table 82. When the voltage of the photomultipliers 56 as the vertical axis is obtained from the exposure time of the CCD camera 44 as the horizontal axis, using the exposure time and voltage conversion table 82, the best voltage to drive the photomultipliers 56 can be automatically set when an image is acquired in the flying spot scanning observation unit 5. A memory memorizes the voltage of the photomultipliers 56 obtained as described above together with position information for each block. When the number of pixels with brightness equal to or higher than the threshold in a block in the optical image information 76 acquired in the optical microscope observation unit 4 is equal to or smaller than the predetermined small number, sharp scanning image information 79 with less noise can be obtained, if, for example, the gain and the offset of the A/D input CH 72 are adjusted in such a way that the information in the corresponding block is removed as noise. The predetermined small number means a number smaller than a predetermined number by which it is judged at step S507 that neurons 26 to be observed exists. A second embodiment has a configuration in which a disk in which a plurality of pinholes or a plurality of slits are formed is inserted into a confocal position on an optical path in an optical microscope observation unit 4, a plurality of confocal images are acquired while moving a focus in the Z direction by rotating the disk, a plurality of acquired confocal images are laminated in the Z direction to form a three-dimensional image, regions in which substances to be observed exist are screened, based on the three-dimensional image, and regions to be inspected with a flying spot scanning observation unit 5 are specified. FIG. 9 is a block diagram that depicts a configuration of a scanning microscope system 100 according to the second embodiment of the present invention. In the scanning microscope system 100 shown in FIG. 9, components similar to those in the scanning microscope system 1 according to the first embodiment shown in FIG. 1 are denoted by the same reference numbers as those in FIG. 1. In FIG. 9, in an optical microscope observation unit 40, a spinning disk device 45 is arranged at a confocal position of an optical path in an optical microscope observation unit 4 according to the first embodiment. The spinning disk device 45 includes a spinning disk 46 in which a light-transmitting portion and a light-proof portion are alternately formed, and a motor 47 that rotates the spinning disk 46 at an approximately constant speed. The scanning optical-microscope-observation unit controller 64 controls the device 45. Even if a Nipkow disk, in which a plurality of pinholes are formed, is used instead of the spinning disk 46, the similar confocal effect can be obtained. The light emitted from the halogen lamp source 41 in the optical microscope observation unit 40 is projected onto the spinning disk 46 through an excitation filter 42. Light passing through slits of the spinning disk 46 is reflected by the reflecting mirror 21, passes through the object lens 23, and converges onto a sample 25. When the sample 25 is irradiated with excitation light, neurons 26 to be observed in the sample 25 emits fluorescence. The fluorescence emitted from the sample 25 is guided in the backward direction along the optical path, and only light that passes through the slits of the spinning disk 46 again passes through a dichroic mirror 43 to form a confocal image on a CCD camera 44. When the spinning disk device 45 is used, confocal image information 92 can be acquired for the thick sample 25. The charges accumulated in the CCD camera 44 are converted into a digital electric signal in an A/D input CH 71, and are sequentially stored at each block of the confocal image information 92 in a memory 73. The memory 73 stores (1) a plurality of pieces of the confocal image information 92 acquired by moving a focus in the Z direction little by little with the optical microscope observation unit 40, (2) brightness image information 93 created from the plurality of pieces of the confocal image information 92, (3) a scanning map 77 created from the brightness image information 93, and the like. An image processor 74 constructs a two-dimensional image from the confocal image information 92 stored in the memory 73 through a main controller 61, and displays the image on a monitor 8. Moreover, the unit 74 constructs a three-dimensional image 95 by laminating a plurality of pieces of confocal image information 92 in the Z direction, and displays the image on the monitor 8. FIG. 10 is a view of the three-dimensional image 95 made by laminating in the Z direction a plurality of pieces of the confocal image information 92 stored in the memory 73. Though a neuron 26 is recognized as a point in one confocal image 92, relations as a neuron 26 can be recognized in the three-dimensional image 95. Diagonally shaded portions in FIG. 10 are blocks in which a neuron 26 to be observed exists. A computer 60 includes a brightness-image-information creator 65 in addition to components of the computer 6 in the first embodiment. The brightness-image-information creator 65 creates the brightness image information 93 obtained by collecting, in the X and Y directions, information on all the pixels which have the highest brightness among pixels in the Z direction of the three-dimensional image 95, and a scanning map creator 66 creates a scanning map 77, based on the created brightness image information 93. FIG. 11 is a flow chart that depicts processing procedure by which the scanning map 77 is created, and which are inserted between step S501 and step S506 in FIG. 5. In the first place, an optical path in a microscope main body 2 is switched to the optical microscope observation unit 40 at step S501 in the first embodiment. Then, the optical-microscope-observation unit controller 64 extracts the excitation light from white light emitted from the halogen lamp source 41 in the optical microscope observation unit 40 with the excitation filter 42 and the excitation light enters the microscope main body 2 from an optical path switch 3 through the dichroic mirror 43 and the slits of the spinning disk 46 under control of the unit 64. A microscope-main-body controller 62 controls the excitation light that enters the microscope main body 2 so that the light irradiates the sample 25 mounted on a motor-driven XY stage 24 through the reflecting mirror 21 in the microscope main body 2, and the object lens 23 installed in the revolver 22 (step S111). When the excitation light irradiates the sample 25, the neurons 26 to be observed in the sample 25 emits fluorescence. The fluorescence emitted from the sample 25 is guided in the backward direction along the optical path, and only light that passes through the slits of the spinning disk 46 again passes through a dichroic mirror 43, and the CCD camera 44 receives the light (step S112). The charges accumulated in the CCD camera 44 according to the amount of the light are converted into a digital electric signal in the A/D input CH 71, and are stored in one block in the confocal image information 92 (step S113). When the processing is not completed for all blocks (NO at step S114), the processing returns to step S112 to acquire the image of the subsequent block. When the processing of image acquisition is completed for all blocks (YES at step S114), the focus of the microscope main body 2 is moved in the Z direction of a little (step S115). If n pieces of the confocal image information 92 are not acquired (NO at step S116), the processing returns to step S112 to acquire the subsequent confocal image information 92. On the other hand, if n pieces of the confocal image information 92 are acquired (YES at step S116), a plurality of pieces of the acquired confocal image information 92 are laminated in the Z direction to form the three-dimensional image 95 (step S117). The brightness-image-information creator 65 searches for the brightness of each pixel in the three-dimensional image 95 in the Z direction (step S118), processing that the highest brightness is assumed to be a brightness of the pixel is repeated for each pixel in the confocal image information 92 to form the brightness image information 93 (step S119), the processing returns to step S506 in the first embodiment, and processing of creating the scanning map 77 is continued. FIG. 12 is a flow chart that depicts other processing procedure by which the scanning map 77 is created, and which are inserted between step S601 and step S605 in FIG. 6. Processing from step S121 to step S123 is the same as the processing from step S111 to step S113 through which the image of one block in the confocal image information 92 is acquired. Processing from step S124 to step S128 is also the same as the processing from step S115 to step S119 through which blocks in the acquired confocal image information 92 are laminated in the Z direction to obtain the three-dimensional image 95 and the brightness image information 93. In the processing shown in FIG. 12, after acquiring the image of one block in the confocal image information 92, blocks acquiring the image are laminated in the Z direction, to obtain the three-dimensional image 95 for one block and the brightness image information 93 for one block. The scanning map 77 may be created according to processing shown either in FIG. 11, or in FIG. 12. When processing of creating the scanning map 77 is completed, processing of searching the scanning map 77 can be started in the similar manner to that of the first embodiment to acquire the scanning image information 79 of one block registered in the scanning map 77 with the flying spot scanning observation unit 5. Though the spinning disk device 45 is used in the second embodiment in order to obtain the confocal image information 92, there can be applied a configuration, instead of using the spinning disk device 45, in which image processing such as deconvolution is performed for the optical image information 76 acquired in the first embodiment to remove portions, which are out of focus, other than the focus included in the optical image information 76. In this case, image processing such as deconvolution can improve accuracy in screening of the neurons 26. As explained above in detail, according to the second embodiment, an optical tomogram of the sample 25 can be acquired without performing the image processing such as deconvolution to obtain sharp scanning image information 79 on a plane corresponding to the focus position, because the spinning disk device 45 is arranged in the CCD camera 44 in addition to the effect of the first embodiment. The three-dimensional image 95 of the sample 25 can be obtained by laminating the confocal image information 92 in the Z direction. Moreover, since the brightness image information 93 is created by collecting, in the X and Y directions, information on all the pixels that have the highest brightness among pixels in the Z direction of the three-dimensional image 95, and the scanning map 77 is created, based on the brightness image information 93, screening with high accuracy can be realized without overlooking neurons 26 with possibility that it is easy to miss the cells due to the thickness of the sample 25 in the Z direction. A third embodiment is a combination of the first embodiment and the second embodiment, and has a configuration in which a plurality of pieces of confocal image information 92 acquired by moving a focus in the Z direction little by little with a optical microscope observation unit 40 are screened respectively to form a three-dimensional scanning map, and a region to be observed with the flying spot scanning observation unit 5 is specified as a three-dimensional region. FIG. 13 is a block diagram that depicts a configuration of a scanning microscope system 200 according to the present invention. In the scanning microscope system 200 shown in FIG. 13, components similar to those in the scanning microscope system 1 according to the first embodiment shown in FIG. 1, and in the scanning microscope system 100 according to the second embodiment shown in FIG. 9 are denoted by the same reference numbers as those in FIG. 1 and FIG. 9. An optical microscope observation unit 40 has a configuration in which a spinning disk device 45 is arranged at a confocal position on an optical path to acquire a confocal image. An optical-microscope-observation unit controller 64 acquires a plurality of the confocal image information 92 obtained by moving a focus little by little in the Z direction with a optical microscope observation unit 40. A scanning map creator 66 creates a scanning map 77 for each of the acquired confocal image information 92 according to the flow chart in FIG. 5 or FIG. 6, and laminates the above scanning maps 77 in the Z direction to form a three-dimensional scanning map 97. FIG. 14A is a view that depicts an example of the three-dimensional scanning map 97, in which a region A represents positions of blocks registered as blocks, which acquires images with the flying spot scanning observation unit 5, according to the processing at step S508 or step S607 in the scanning map creator 66. Accordingly, a region to be observed with the flying spot scanning observation unit 5 can be specified as a three-dimensional region, using the three-dimensional scanning map 97. Then, processing that acquires scanning image information 79 excited by each fluorescence when a sample is multiple-stained is explained in the third embodiment. When the sample 25 is multiple-stained, an excitation filter 43 in the optical microscope observation unit 40 is changed according to the fluorescence with which the sample 25 is stained, and the wavelength of the excitation light with which the sample 25 is irradiated is switched to respectively acquire a confocal image 92. The scanning map 77 is created for each piece of acquired confocal image information 92 to laminate it in the Z direction. Thereby, a three-dimensional scanning map 97 like one as shown in FIG. 14A is created for each fluorescence with which the sample 25 is stained. For example, when the sample 25 is stained with triple fluorescence excited by three wavelengths of 351 nm, 488 nm, and 543 nm, the wavelength of the excitation filter 43 in the optical microscope observation unit 40 is switched to 351 nm in the first place for irradiation of the excitation light, and, for example, the three-dimensional scanning map 97 shown in FIG. 14A is created. The region A is an region excited by light with a wavelength of 351 nm. A cell in the region A emits fluorescence when excited by light with a wavelength of 351 nm. Similarly, when the excitation filter 43 in the optical microscope observation unit 40 is changed to cause the excitation light of 488 nm for irradiation, a three-dimensional scanning map 98 in FIG. 14B is created, the excitation filter 43 is changed to cause the excitation light of 543 nm for irradiation, and a three-dimensional scanning map 99 in FIG. 14C is created, it is found that a cell in a region B emits fluorescence when excited by light with a wavelength of 488 nm, and a cell in a region C emits fluorescence when excited by light with a wavelength of 543 nm. Then, the three-dimensional scanning map 97, the three-dimensional scanning map 98, and, the three-dimensional scanning map 99 are superimposed to create a three-dimensional scanning map 100 shown in FIG. 14D. According to the three-dimensional scanning map 100, it is found that two kinds of cells, one reacting to excitation light with a wavelength of 351 nm and the other reacting to excitation light with a wavelength of 488 nm, exist in a region D in which the region A and the region B overlap one another, two kinds of cells, one reacting to excitation light with a wavelength of 351 nm and the other reacting to excitation light with a wavelength of 543 nm, exist in a region E in which the region A and the region C overlap one another, and only one kind of a cell exists in a region in which there are no overlapped regions. An image processor 74 performs image processing in such a way that the region A of the three-dimensional scanning map 97 is displayed blue, the region B of the three-dimensional scanning map 98 is displayed green, the region C of the three-dimensional scanning map 99 is displayed red. The three-dimensional scanning map 97, the three-dimensional scanning map 98, the three-dimensional scanning map 99, which undergo the above image processing, and the three-dimensional scanning map 100 overlapping the above three maps are displayed on the monitor 8. When the three-dimensional scanning map 100 and the like are displayed on the monitor 8, the observer can visually understand that two kinds of cells, one reacting to excitation light with a wavelength of 351 nm and the other reacting to excitation light with a wavelength of 488 nm, exist in a region D in which the region A and the region B overlap one another, two kinds of cells, one reacting to excitation light with a wavelength of 351 nm and the other reacting to excitation light with a wavelength of 543 nm, exist in a region E in which the region A and the region C overlap one another, and only one kind of a cell exists in a region in which there are no overlapped regions. According to the three-dimensional scanning map 100, information on the kind of the laser beam source 51 and the laser wavelength, in addition to the X, Y, and Z positions information of a block to be irradiated with laser beam, can be obtained for each block. Though image acquisition conditions is obtained from the three-dimensional scanning map 100, the image acquisition conditions, by which the scanning image information 79 is acquired, are memorized in the memory 73 in the computer 600 as an image acquisition condition table 110. FIG. 15 is a view that depicts one example of the image acquisition condition table 110. The image acquisition condition table 110 memorizes kinds 111 of laser beam sources; laser wavelengths 112, and image acquisition conditions such as X, Y, and Z positions 113 of blocks. A flying-spot-scanning-observation unit controller 68 automatically selects the kind 111 of the laser beam source, and the laser wavelength 112 according to the image acquisition conditions memorized in the image acquisition condition table 110 to automatically acquire the scanning image information 79 at the X, Y, and Z positions 113 of the memorized block. As described in the third embodiment, the X, Y, and Z positions of the registered block can be accurately obtained. However, when registered blocks in the sample 25 are repeatedly observed for a long time while controlling a motor-driven focus adjusting unit such as the motor-driven XY stage 24, heat by a halogen lamp source 41 or a laser beam source 51, and the like causes rise in the temperature around the microscope to generate a possibility that deflection in the microscope main body 2 is caused. Moreover, repeated moving of the motor-driven XY stage 24 causes position displacement, and a possibility that the X, Y, and Z positions of the blocks registered as a region to be observed are displaced. In such case, on a regular basis, or, before observation with the flying spot scanning observation unit 5, the microscope main body 2 is connected to the optical microscope observation unit 40, and the position displacement in the Z direction is corrected after auto focusing with use of image data in the CCD camera 44. Moreover, when position displacement in pixels is found to be generated in comparison between the image acquired by the previous auto focusing and that by the current auto focusing, the amount of the displacement is automatically calculated to correct the position displacement of the X and Y positions. When the flying spot scanning observation unit 5 is connected to the microscope main body 2 after completion of the correction of the X, Y, and Z positions, the image information can be always acquired at the same position. Moreover, position displacement in the Z direction may be corrected by providing a well-known passive, or active auto focus (AF) unit in the optical microscope observation unit 4. As explained above in detail, according to the third embodiment, useless image acquisition time such as time, which is required to search for cells in conformity to the purpose of observation in each block, can be reduced, in addition to the effects of the embodiments 1 and 2. Moreover, as registered blocks is not irradiated with unnecessary laser beam even when a sample 25 is multiple-stained, fading in fluorescence can be prevented. Further, as registered blocks is irradiated with required laser beam, the scanning image information 79 is less disturbed by noise caused by cross talk between beams of laser beam. Furthermore, as observes is not required to set the laser beam source 51 as one of the image acquisition conditions for each block, the load of observers can be reduced. A scanning microscope system according to the present invention has an advantage that the system can quickly acquire a sharp scan image with a scanning microscope, because only a selection region is observed by fluorescence microscopy, using excitation light from a laser beam source in a flying spot scanning observation unit, after a sample is screened, using excitation light output from a white light source at an optical microscope observation unit to select the region in which there is a substance to be observed. Although the invention has been described with respect to a specific embodiment for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art which fairly fall within the basic teaching herein set forth.
	abstract	A radiation therapy system optimized for treating extremities such as the breast has unique geometrical features that enable the system to deliver an accurately located prescribed dose to a target volume while eliminating or reducing the collateral dose delivered to the rest of the patient. The patient lies in a prone position on a rotating, shielded table, with the anatomy to be treated protruding through an orifice in the table into the path of a radiation beam. An optional integral imaging system provides accurate target volume localization for each treatment session. Utilizing the effects of gravity on a prone patient maximizes the separation of a target volume within the breast to adjacent critical structures such as the chest wall, heart and lungs, thereby reducing long term complications not associated with the primary disease. A shielded interface surface between the radiation source and the patient reduces patient dose due to scattered or stray radiation. A shielded enclosure for the radiation sources combined with the shielded interface surface eliminates the need for primary shielding in the room and allows the therapy system to be used in a transportable, mobile facility.
055770908	description	DETAILED DESCRIPTION The ELMO experiments form a basis for calculating x-ray flux incident on an imaginary surface lying within a hot electron plasma annulus of the x-ray device of the present invention. However, the present invention departs from the ELMO work by replacing hydrogen (Z=1) as the fill gas with xenon (Z=54) to take advantage of the bremsstrahlung power scaling with Z.sup.2 (see Equation 1). Preferably, the present invention utilizes one of the noble gases (xenon, helium, neon, argon). For computational convenience and simplicity, it is assumed that the hot electrons are distributed uniformly throughout a well defined annular geometry. This calculation, although not rigorous, provides an order of magnitude estimate of the radiant flux levels of the device of the present invention as an x-ray source. The results of this calculation compare favorably to the dosage required for pasteurization and sterilization of various food products. It should be noted that thick target x-rays, produced by scattered ring electrons striking the sidewalls, x-ray emission from electron-atom collisions in the gas, and x-rays penetrating the irradiated food product are excluded from this estimation, making the results of the calculation a very conservative estimate of the radiation levels expected from the device of the present invention. Referring to FIG. 4, a sharp boundary model is assumed for a hot electron plasma annulus having inner and outer radii R.sub.1, R.sub.2, respectively. The x-ray power incident per unit area on an imaginary cylindrical surface of radius a (where a<R.sub.1 <R.sub.2) is calculated. The origin of the cylindrical coordinate system r,.theta.,z is taken at the right-hand side on the axis of the annulus as shown in FIG. 5. A truncated section of annulus is shown by solid lines in FIG. 5, while the remainder of the annulus is indicated by dotted lines. The truncated section is constructed by tangents drawn at the radius a, perpendicular to the z-axis. The angle of incidence .phi. is defined by an outward normal to the cylindrical surface drawn at the point a,0,-l, and a line of sight from an elementary volume of plasma rdrd.theta.dz within the truncated annulus. Radiation emitted from the truncated plasma volume, passes through the cylindrical surface at a,0,-l with an angle of incidence .phi. lying in a range of 0<.phi.<90.degree., while radiation from all other plasma regions, .phi.>90.degree., pass through the surface from the interior side. The radiation incident from the interior is neglected under the assumption that it is absorbed by material contained within a radius a. Inspection of FIGS. 4 and 5 reveal the following relations: EQU r.sub.1.sup.2 =r.sup.2 +a.sup.2 -2arCos.theta., Equation 3 EQU R.sup.2 =(z+l).sup.2 +r.sub.1.sup.2 =(z+l).sup.2 +r.sup.2 +a.sup.2 -2arCos.theta., Equation 4 where l is the distance along the z-axis from the edge of the annulus to the irradiated area, and the cosine of the angle of incidence Cos.phi. at the point a,0,-l is: ##EQU1## The limits of integration are also obtained from FIGS. 4 and 5: The angle .theta. varies over the range, ##EQU2## while the radius r varies from R.sub.1 .ltoreq.r.ltoreq.R.sub.2 and z varies from 0.ltoreq.z.ltoreq.L. Continuing the calculation of radiant flux emitted as bremsstrahlung from the annulus, the radiant flux or power dP.sub.s radiated by an elementary plasma volume within the annulus is EQU dP.sub.s =wrdrd.theta.dz, Equation 6 where the radiated power density w is defined by Equation 1. It is assumed that the radiation is distributed uniformly over a solid angle of 4.pi. steradians. This assumption is not quite correct, for the direction of radiation emitted by energetic electrons will be influenced by the distribution of the energetic electron velocities with respect to the magnetic field and the orientation of the magnetic field within the annulus. These effects tend to increase the x-ray emission in the direction of the axis, i.e., toward the imaginary surfce defined by the radius a, and tend to reduce the x-ray power emitted from adjacent parts of the annulus that would otherwise contribute to the radiant flux through the surface at the point a,0,-l. These effects are expected to offset one another, and for this order of magnitude estimation, they can be neglected without serious loss of accuracy. Under these assumptions, the radiant intensity of the x-rays I, or radiant flux per unit solid angle is calculated as, ##EQU3## With the elementary plasma volume at the apex, the solid angle d.OMEGA. subtended by the surface area dA on the imaginary surface at the point a,0,-l is, ##EQU4## and the bremsstrahlung power intercepted by this area is ##EQU5## Whereby, the irradiance or radiated power per unit area ##EQU6## incident at the reference point from the elementary plasma volume is ##EQU7## Substituting the expressions for R and Cos.phi. and integrating over the radiating source (i.e., the plasma annulus) yields the total bremsstrahlung power per unit area incident at the point a,0,-l radiated by the truncated annulus, is ##EQU8## where, ##EQU9## The factor of 2 in front of the integral is due to symmetry in the integration over .theta. as it is performed only from .theta..sub.1 to 0. As a quantitative example, consider a hot electron plasma annulus in the device of the present invention with dimensions R.sub.1 =0.5 m, R.sub.2 =0.6 m, and l=1 m. We take an imaginary cylindrical surface with a radius a=0.2 m, coaxial with the annulus, and calculate the incident power per unit area, i.e., the x-ray irradiance, incident on this surface for a background plasma density n.sub.i =5.times.10.sup.18 m.sup.-3, with ring electron density n.sub.e =0.1 n.sub.i, and an electron temperature T.sub.e =2 MeV in the rings. The results of integrating Equation 11 in watts per square meter incident at the cylindrical surface is plotted as a function of position l along the axis in FIG. 6. As expected, the irradiance is distributed symmetrically about the middle of the cylindrical axis. The x-ray irradiance ranges from about 2.4 kw/m.sup.2 at the ends of the 0.2 m radius cylindrical surface to greater than 4 kw/m.sup.2 at the center. To compare dose rates obtainable from the x-ray device of the present invention with dose rates available from conventional food irradiation facilities, the calculated irradiance values must be converted to exposure rates, i.e., from watts/m.sup.2 to Rad/s. The American Institute of Physics Handbook gives the exposure-to-fluence conversion in air as ##EQU10## where the photon energy E is in MeV. Assuming that the average energy of x-ray photon emission from the plasma is equal to the average energy of the electrons in the annulus, i.e., the electron temperature T.sub.e =2 MeV, then, the average number of photons/s for an incident radiant flux of 1 w/m.sup.2 is ##EQU11## where, T.sub.e is in MeV. Dividing Equation 13 by Equation 12 and cancelling out the photon energy gives a conversion factor of ##EQU12## Now, referring to the plot in FIG. 6, an object placed in the radiation field within an imaginary surface of radius a=0.2 m will be subjected to a dose rate of about 700 roentgen/s at the ends of the axis to about 1,170 roentgen/s at the middle of the axis of the device of the present invention. Conversion from exposure in roentgens to absorbed dose in Rads for an equivalent energy fluence on the medium, is obtained through the use of the following relation as discussed in T. N. Padikal, "Medical Physics," A Physicist's Desk Reference; Second Edition of Physics Vade Mecum, H. L. Anderson, editor in chief, page 227, American Institute of Physics, 1989. ##EQU13## where X is the exposure in roentgens, D.sub.H2O is the dose absorbed in Rads by a medium which has a mass energy absorption coefficient (.mu..sub.en /.rho.).sub.H2O equivalent to that of water. The values of the absorption coefficient (.mu..sub.en /.rho.) for air and water are 2.342.times.10.sup.-3 and 2.604.times.10.sup.-3 m.sup.2 /kg, respectively, for a mean photon energy of 2 MeV. Evaluating the term in the brackets results in a factor of 0.966 multiplying the exposure X in roentgens to obtain the dose in Rads absorbed by a water-like material. The overall conversion factor from w/m.sup.2 to Rads/s is 0.281 Rads/s/w/m.sup.2. Continuous dose rates of 668 Rad/s at the ends and 1,139 Rad/s at the middle of the axis of the x-ray device of the present invention are obtained as a result of the calculation. The total bremsstrahlung power radiated by the annulus in the device of the present invention is obtained by evaluating the power density w for the chosen parameters and forming its product with the volume of the annulus. Using the parameters specified above and Equation 1, the total bremsstrahlung power radiated by the annulus is 54 kw for background plasma density of 5.times.10.sup.18 m.sup.-3. The range of usable background plasma densities in the x-ray device of the present invention is determined by the plasma frequency f.sub.p, i.e., the cutoff frequency for electromagnetic propagation through a plasma. The plasma frequency f.sub.p is given by, ##EQU14## where n.sub.c is the critical density for cutoff of electromagnetic wave propagation through the plasma, e is the electronic charge, m.sub.e is the electron mass, and e.sub.0 is the permittivity of free-space. If the background plasma density exceeds the critical density value, microwave power cannot penetrate to the resonant region of the mirror field, so that ECH and hot electron production ceases. The relation between cutoff plasma frequency as a function of density, Equation 16 is plotted in FIG. 7. Referring to FIG. 7, high power tubes, generating microwave frequencies of 9 GHz to 90 GHZ, are required to operate an x-ray device of the present invention with background plasma densities over a range from 10.sup.18 to 10.sup.20 m.sup.-3. As discussed hereinafter, the maximum plasma density in the x-ray device of the present invention will not exceed n.sub.i <5.times.10.sup.19 m.sup.-3, so that microwave tubes with frequencies <60 GHz will suffice for operation. Gyrotron tubes which generate >200 kw over the specified microwave frequency range are available from the Microwave Power Tube Division of Varian Associates in Palo Alto, Calif. As a result of Department of Energy (DOE) investments in high-power microwave tubes, sources operable at frequencies of 28, 56, 90, and 140 GHz with nominal output powers of 200 kw are commercially available. Additionally, the magnitudes of magnetic fields that cause electron gyration about a field line to resonant with a microwave frequency from 9 to 90 GHz is 0.32 to 3.2 T (3.2 to 32 kgauss), respectively. The magnetic field for electron cyclotron resonance at 56 GHz is .congruent.2.0 T. As magnitudes of the resonant magnetic fields required are relatively modest, and the coil geometry is a simple solenoid, suitable electromagnetic coils are readily obtainable from commercial fabricators. The bremsstrahlung radiated power is dependent on the annular plasma density. The results of integrating Equation 11 for three values of background plasma densities, n.sub.i =5.times.10.sup.18, 10.sup.19, and 5.times.10.sup.19 m.sup.-3 with all other plasma parameters and dimensions remaining the same as the previous calculation, is plotted in FIG. 8. Here, the calculated peak values of radiant flux at the mid point of the axis are 4, 16, and 400 kw/m.sup.2 for background plasma densities n.sub.i of 5.times.10.sup.18, 10.sup.19, and 5.times.10.sup.19 m.sup.-3, respectively. The values of peak radiant flux, given above, correspond to dose rates of about 1.16, 4.54, and 116 kRad/s under the assumption that the mass energy adsorption coefficient of food products is equivalent to the mass energy adsorption coefficient of water. Thus, increasing the annulus plasma density significantly alters the radiated bremsstrahlung power output from the x-ray device of the present invention over a wide range. FIG. 9 is a schematic representation of the x-ray device of the present invention. The device 10 of the present invention includes two electromagnetic coils 12 that, when energized, provide the magnetic mirror field required to confine the plasma, as discussed above. The electromagnetic coils 12, preferably, are capable of producing a magnetic field having a magnitude in the range of 0.32 to 3.2T (3.2 to 32 kgauss). Device 10 includes a vacuum chamber 14 suitable for confining a gas 20. Preferably, the gas utilized in the present invention is one of the noble gases such as xenon (Xe), helium (He), neon (Ne) or argon (Ar). The chamber wall 16 is formed of a material that will pass x-rays, and may be made of steel, for example. Wall 16 is provided with a terminal 18 for microwave heating of the gas 20. The terminal 18 is connected to a microwave source 22. Microwave source 22 will preferably be capable of operating at frequencies in the range of 9 GHz to 90 GHz with a nominal output power of about 200 kw. As discussed above, the microwave frequency is chosen to be resonant with the second harmonic of the electron cyclotron frequency of particular regions of the mirror field. Heating of the gas 20 in this manner gives rise to the annular plasma structure shown as 24 in FIG. 9, as confined by the mirror magnetic field. In the present invention, the background plasma density n.sub.i in chamber 14 is preferably in the range of 10.sup.18 to 10.sup.20 electrons/m.sup.3, with the annular plasma density n.sub.e =0.1n.sub.i. The electron temperature Te in the annular plasma is preferably about 2 MeV. Chamber wall 16 includes a central cylinder 26 with interior opening 28 that is open on both ends to the surrounding air. The device 10 of the present invention includes a support 32 for supporting and locating the product 30 proximate to the chamber 14 for receiving x-rays radiating therefrom. Support 32 may be stationary, or preferably mobile, as shown in the embodiment of FIG. 9, in which support 32 includes a conveyor 34 for moving the product 30 through opening 28 in cylinder 26. This annular geometry shown in FIG. 9 is particularly well suited to irradiating food products moving through cylinder 26, as these products will be completely encircled by the radiating media. While the present invention is particularly effective in irradiating food products, it is applicable to any product where irradiation is desired. FIG. 10 illustrates an embodiment of the present invention in which a plurality of chambers 14 are arranged coaxially in series and each is connected to a microwave source 22. In certain applications, a plurality of microwave sources may be used. The arrangement of FIG. 10 increases the throughput capacity of the device. Further, this arrangement permits certain electromagnetic coils 12A to be shared between chambers 14. This reduces the number of coils required for n chambers from 2n to n+1, which results in capital savings. Radiation from chambers 14 is directed not only radially inward toward central opening 28 but also radially outward. In the embodiments of FIGS. 9 and 10, this outward radiation can be taken advantage of by circulating the products 30 on a conveyor system, for example, that makes several passes within a shielded room housing the x-ray devices 10. In this manner, the products 30, e.g. food products, receive a large x-ray dose prior to entering the central opening 28 in the device(s) and thereby reduces the time required in central region 28 for adequate exposure. Another embodiment of the present invention, shown in FIG. 11, takes further advantage of such outward radiation and eliminates the need for a central channel with a support or conveyor located therein. In such embodiment, the devices 10 are arranged in an array which could take any suitable form such as a rectangle or square (as shown). Such array surrounds central open area 36. Located within open area 36 is support 32 for locating the product(s) 30 proximately to x-ray devices 10 of the present invention. Support 32 may be stationary and may simply comprise a floor area, or may be movable, such as an elevator that lifts/lowers a pallet of food products 30 into/out of central open area 36. With reference again to FIG. 9 and assuming the platform 32 includes a conveyor 34, the previous calculations can be used to calculate the total dose D received by a cylindrical object passing through x-ray device 10 with a plasma annulus 24 of length L at a constant velocity V. Converting the results of the calculations plotted in FIG. 6 to Rads/s, the dose rate R(z) is modeled as a parabolic function of the distance x along the axis as EQU R(z)=-1,799(z-0.5).sup.2 +1,139, Equation 17 and this equation is plotted as a function of axial position in FIG. 12. For comparison, the curve appearing in FIG. 6 (after conversion to Rads/s) is also replotted in FIG. 12. The parabolic fit is very good as is seen in the graph. The analytical model is a convenient means of calculating the total dose D received by a cylindrical object transiting a plasma annulus 24 of length L at a constant velocity v. Assuming that only radiation directly entering the cylindrical surface is absorbed, i.e., neglecting the radiation incident on the circular ends and that penetrating through the product, e.g. food, the dose absorbed at an axial position z and radius r is given by the product of the rate of absorbed dose R(z) multiplied by the time dt spent at the position r,z. Since a point on the surface is moving at a constant velocity v, the time dt=dz/v, and by symmetry, dD(z)=2.pi.r R(z)dz/v is the dose absorbed through the elemental surface d.sigma.=2.pi.r dz. The total dose D in Rads absorbed by the cylindrical object is calculated by integrating Equation 17 along the z axis, i.e., ##EQU15## Using the device parameters from earlier calculations, i.e., L=1 m, and the radius of the imaginary surface a=0.2 m, the total dose received D is plotted as a function of velocity v.sub.i in FIG. 13. The products will receive a total dose better than 10 to 60 kRads (100 to 600 Gy) moving through x-ray device 10 at a speed of 0.1 to 0.02 m/s, (corresponding to a transit time of 10 to 50 s) respectively. This calculation does not include bremsstrahlung generated by the impact of energetic electrons on the walls 16 of device 10, so that this is a minimum dosage calculation. Additionally, dose rates absorbed by the product, e.g. food, are controlled by the amount of microwave power put into device 10 and the transsit time of the product through device 10. Thus, dosage may be lowered by lowering the microwave power input, or passing the products 30 through device 10 at higher speeds. The radiated power from x-ray device 10 of the present invention is consistent with achieving a high throughput of irradiated food products when compared to x-ray dosages required to perform food preservation treatments. The annular geometry of the x-ray device of the present invention (FIGS. 9 and 10) is highly amenable to irradiating products moving through the device, especially food products, as these products will be completely encircled by the radiating media. Operating a plurality of devices in series (FIG. 10) increases product throughput and results in certain capital savings. Arrangement of the x-ray devices in an array (FIG. 11) permits irradiation of large products. The calculated estimates of radiant flux of the present invention are conservative and do not take into account several factors that enhance x-ray intensity. These factors include the thick target bremsstrahlung from the side walls and the bremsstrahlung collisions with unionized gas atoms and electrons. Inclusion of these factors may increase the dose rates an order of magnitude over the calculated values, and accordingly, reduce the required exposure time by the same factor. While the present invention has been described in terms of preferred embodiments, various changes and modifications will become apparent to those having skill in the pertinent art. All such modifications and enhancements are intended to fall within the scope and spirit of the present invention, limited only by the following claims.
062597671	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to an X-ray device which includes an X-ray imaging apparatus and an X-ray generator for powering an X-ray source which co-operates with the X-ray imaging apparatus and also includes a diaphragm unit which is connected to the X-ray source and includes an adjustable diaphragm aperture in order to preset an exposure field on an X-ray image detection device, the diaphragm aperture being adjustable on the one hand by a drive unit which is controlled by a control system and on the other hand by adjusting means for manual adjustment of the diaphragm aperture. 2. Description of the Related Art X-ray devices of this kind are known for the formation of Bucky images. Such devices utilize image detection devices in the form of film/foil combinations of various formats which are accommodated in suitably dimensioned cassettes. The examiner then selects the cassette format required for the next X-ray exposure and inserts the cassette into the X-ray device. The X-ray device is provided with a measuring device for measuring the cassette format. The control system then adjusts the diaphragm aperture in dependence on the measured cassette format so that the exposure field corresponds to the cassette format or the format of the film present therein. Such X-ray devices require manual adjustment of the exposure field only if the examiner wishes to constrict the exposure field. Since recently so-called "digital" X-ray detectors are used as the image detection devices; such detectors include a large number of (for example, 2000.times.2000) detector elements which are arranged in the form of a matrix, are sensitive to light or X-rays and generate electric signals which are dependent on the X-ray intensity and are processed in the X-ray device. The X-ray device may comprise various imaging units, for example a grid exposure table for forming X-ray images of a supine patient and/or a grid wall stand for forming X-ray images of a standing patient; each of these units is provided with only a single digital detector of this kind whose dimensions, therefore, have to correspond to the largest possible exposure format (for example, 43.times.43 cm). Automatic adjustment of the diaphragm aperture to the format of this image detector, however, would in most cases require a rather substantial manual restriction of the exposure field, thus complicating the use of such an apparatus. Citation of a reference herein, or throughout this specification, is not to be construed as an admission that such reference is prior art to the Applicants' invention of the invention subsequently claimed. SUMMARY OF THE INVENTION It is an object of the present invention to simplify the use of an X-ray device whose imaging unit (units) has (have) an image detector which has each time only a single (maximum) format. On the basis of an X-ray device of the kind set forth this object is achieved in that there is provided a storage device which co-operates with the control system and in which a respective set of exposure parameters is stored for each of a number of organs, that each set contains, in addition to the exposure parameters for the X-ray detector, an adjustment value for adjusting the exposure field, and that, when an organ is selected, the adjustment value is fetched and the exposure field is adjusted, by way of the control system and the drive unit, in conformity with the adjustment value associated with the selected organ. The use of a storage device in which respective sets of exposure parameters are stored for various organs has since long been known in the X-ray imaging technique. According to such so-called APR (Anatomically Programmed Radiography) methods, essentially exposure parameters for the X-ray generator, for example the voltage to the X-ray tube, the current through the X-ray tube and the exposure duration, are stored in an organ-dependent manner in order to be fetched and adjusted when the relevant organ is selected. The invention is based on the recognition of the fact that the size of the exposure field is correlated to the organ or to the body region to be imaged by way of the subsequent X-ray exposure. Therefore, for each organ the size of the required exposure field is stored additionally. The stored adjustment value is fetched when the relevant organ is selected and controls, via the control system and the drive unit, the diaphragm unit in such a manner that the preset exposure field is adjusted. After that, the examiner need only slightly change the exposure field, if at all. During manual adjustment of the exposure field the examiner is present in the vicinity of the patient who is arranged, for example on a patient table. However, the other adjusting operations, for example selection of an organ, triggering of an X-ray exposure etc., are carried out at a control desk or a workstation which is situated in a room other than that in which the patient is present. In the embodiment wherein the control system is programmed in such a manner that, after actuation of the adjusting means, the manual adjustment of the exposure field is carried out or preserved independently of an adjustment value fetched before or after that, it is ensured that the manual adjustment made for the exposure of the relevant organ is not overwritten by an adjustment value stored for this organ so that it is canceled again. The appropriately programmed control system then consists effectively of a diaphragm controller which is arranged to control the drive unit and the diaphragm unit, as well as of the workstation which controls all components of the X-ray device as well as the overall exposure procedure. The further embodiment wherein the control system is programmed in such a manner that after an X-ray exposure or a change of a patient to be examined an exposure field adjusted by actuation of the adjusting means is adjusted in conformity with the relevant adjustment value fetched, however, enables a change-over to be made from the manual adjustment to the stored adjustment values when an X-ray exposure or change of patient has taken place after the manual adjustment. Bucky exposures or exposures on the wall stand are generally executed with a given distance between the X-ray source and the image detector, for example 1.15 m. In that case each exposure field corresponds to a given diaphragm aperture. However, it is often desirable to increase or decrease the distance between the X-ray source and the image detector. Therefore, the further embodiment wherein the distance between the X-ray source and the X-ray image detection device is adjustable, further comprising means for measuring this distance, and wherein the control system is programmed in such a manner that in dependence on the measured distance the diaphragm aperture has a value such that the size of the exposure field on the image detection device assumes its preset value, ensures that when said distance is changed, the diaphragm aperture is also readjusted in such a manner that the desired exposure field is obtained in the plane of the image detector. The invention can be used with an image detector indicating a flat detector with light-sensitive or X-ray sensitive detector elements which are arranged in the form of a matrix. The invention, however, can in principle be used for all imaging units involving only a single format of the image detector.
056446080	abstract	The performance of a compact heat exchanger in which a flow of air is employed to cool a flow of water can be enhanced by spraying water as a fine mist into the stream of coolant air. The water droplets, preferably less than 100 microns in diameter, coat the heat exchanger surface on the air side of the heat exchanger and provide evaporative cooling. The preferred form of heat exchange surface has strip fins.
	claims	1. A device for generating extreme ultraviolet and soft x-rays from a gas discharge, operated on the left-hand branch of the Paschen curve, comprising: two main electrodes, between which there is a gas-filled space, wherein each of said two main electrodes exhibits an opening, defining an axis of symmetry, and wherein the electrodes are formed in such a manner that the gas discharge forms exclusively in the volume, determined by an alignment of the openings; and where the plasma channel, generated on the axis of symmetry, is the source for at least one of the extreme ultraviolet and x-rays, and a means for increasing conversion efficiency including an auxiliary electrode provided behind the opening of one of the main electrodes. 2. The device as claimed in claim 1 , wherein at least one of the openings on the side facing away from the space is larger than on the side facing the space. claim 1 3. The device as claimed in claim 2 , wherein the openings exhibit the shape of a truncated cone. claim 2 4. The device as claimed in claim 1 , wherein the anode opening is designed as a non-continuous depression, and in particular as a blind hole. claim 1 5. The device as claimed in claim 1 , wherein each of said main electrodes has a ring-shaped opening, whereby the center of the ring lies on the axis of symmetry. claim 1 6. The device as claimed in claim 1 , wherein a pulse-forming network is provided as a power supply. claim 1 7. The device as claimed in claim 1 , wherein, in addition to the gas inlet and outlet opening for the working gas in the electrode space, there is at least one additional gas inlet or gas outlet opening. claim 1 8. The device as claimed in claim 1 , further comprising a system of capillaries, for vacuum separation, provided between the gas-filled space and highly evacuated areas of the device. claim 1 9. The device as claimed in claim 8 , wherein the system of capillaries is a micro channel plate or a Kumakhov lens. claim 8 10. A device for generating extreme ultraviolet and soft x-rays from a gas discharge, operated on the left-hand branch of the Paschen curve, comprising: two main electrodes, between which there is a gas-filled space, wherein each of said two main electrodes exhibits an opening, defining an axis of symmetry, and wherein the electrodes are formed in such a manner that the gas discharge forms exclusively in the volume, determined by an alignment of the openings; and where the plasma channel, generated on the axis of symmetry, is the source for at least one of the extreme ultraviolet and x-rays, and a means for increasing conversion energy including an auxiliary electrode, which exhibits an opening on the axis of symmetry, provided between the main electrodes. 11. The device as claimed in claim 10 , wherein at least one of the openings on the side facing away from the space is larger than on the side facing the space. claim 10 12. The device as claimed in claim 11 , wherein the openings exhibit the shape of a truncated cone. claim 11 13. The device as claimed in claim 10 , wherein the anode opening is designed as a non-continuous depression, and in particular as a blind hole. claim 10 14. The device as claimed in claim 10 , wherein each of said main electrodes has a ring-shaped opening, whereby the center of the ring lies on the axis of symmetry. claim 10 15. The device as claimed in claim 10 , wherein a pulse-forming network is provided as a power supply. claim 10 16. The device as claimed in claim 10 , wherein, in addition to the gas inlet and outlet opening for the working gas in the electrode space, there is at least one additional gas inlet or gas outlet opening. claim 10 17. The device as claimed in claim 10 , further comprising a system of capillaries, for vacuum separation, provided between the gas-filled space and highly evacuated areas of the device. claim 10 18. The device as claimed in claim 17 , wherein the system of capillaries is a micro channel plate or a Kumakhov lens. claim 17 19. A device for generating extreme ultraviolet and soft x-rays from a gas discharge, operated on the left-hand branch of the Paschen curve, comprising: two main electrodes, between which there is a gas-filled space, wherein each of said two main electrodes exhibits an opening, defining an axis of symmetry, and wherein the electrodes are formed in such a manner that the gas discharge forms exclusively in the volume, determined by an alignment of the openings: and where the plasma channel, generated on the axis of symmetry, is the source for at least one of the extreme ultraviolet and x-rays, wherein each of said main electrodes has a plurality of openings. 20. The device as claimed in claim 19 , wherein the openings in the main electrodes are arranged on a circle, through whose center runs the axis of symmetry. claim 19 21. The device as claimed in claim 19 , wherein at least one of the openings on the side facing away from the space is larger than on the side facing the space. claim 19 22. The device as claimed in claim 21 , wherein the openings exhibit the shape of a truncated cone. claim 21 23. The device as claimed in claim 19 , wherein the anode opening is designed as a non-continuous depression, and in particular as a blind hole. claim 19 24. The device as claimed in claim 19 , wherein each of said main electrodes has a ring-shaped opening, whereby the center of the ring lies on the axis of symmetry. claim 19 25. The device as claimed in claim 19 , wherein a pulse-forming network is provided as a power supply. claim 19 26. The device as claimed in claim 19 , wherein, in addition to the gas inlet and outlet opening for the working gas in the electrode space, there is at least one additional gas inlet or gas outlet opening. claim 19 27. The device as claimed in claim 19 , further comprising a system of capillaries, for vacuum separation, provided between the gas-filled space and highly evacuated areas of the device. claim 19 28. The device as claimed in claim 27 , wherein the system of capillaries is a micro channel plate or a Kumakhov lens. claim 27
	claims	1. A method for fusing particles, comprising:generating a substantially uniform electromagnetic field within an evacuated region;populating the chamber with a plurality of chargeable particles;pulsing an energizing beam a first instance along a beam path that is substantially parallel to the uniform electromagnetic field to energize at least some of the chargeable particles and cause them to travel in a circular pattern;pulsing the energizing beam a second instance along the same beam path after a period of time corresponding to a cyclotron frequency of the particles that is based on a charge of the particles and a mass of the particles; andpulsing the energizing beam a plurality of instances after the second instance at the cyclotron frequency to energize the particles sufficiently to cause at least two of the particles to collide at the location of the beam path with sufficient energy to fuse. 2. The method of claim 1, further comprising bounding the particles along the axis of the beam path in a first direction via a first confining electrode configured to repel the particles. 3. The method of claim 2, further comprising bounding the particles along the axis of the beam path in a second direction via a second confining electrode configured to repel the particles, such that the particles are axially bounded between the first confining electrode and the second confining electrode. 4. The method of claim 3, wherein at least one of the first confining electrode and the second confining electrode comprises a ring electrode. 5. The method of claim 3, wherein at least one of the first confining electrode and the second confining electrode comprises a disk electrode. 6. The method of claim 3, wherein at least one of the first confining electrode and the second confining electrode comprises a hyperbolic electrode. 7. The method of claim 1, further comprising collecting at least one particle via a stray particle collection electrode configured to collect particles that are not on a trajectory that results in being positioned along the beam path when the energizing beam is pulsed. 8. The method of claim 1, further comprising adding additional particles at a rate corresponding to a rate at which particles are fusing. 9. The method of claim 1, further comprising collecting energy from the pulsed energizing beam that is not absorbed by one of the plurality of particles via a beam recovery system. 10. The method of claim 1, further comprising evacuating the evacuated regions via a vacuum apparatus. 11. The method of claim 1, wherein pulsing an energizing beam comprises pulsing a laser beam. 12. The method of claim 1, wherein pulsing an energizing beam comprises pulsing an electron beam. 13. The method of claim 1, wherein pulsing an energizing beam comprises pulsing a neutral atom beam. 14. The method of claim 1, wherein pulsing an energizing beam comprises pulsing a proton beam. 15. The method of claim 1, further comprising injecting additional chargeable particles to replenish the chamber. 16. The method of claim 1, wherein the population of particles comprises deuterium particles. 17. The method of claim 1, wherein the population of particles comprises tritium particles. 18. A fusion reactor for fusing particles via multiple periodic ion collisions, comprising:a first evacuated region;a first plurality of chargeable particles positioned within the first evacuated region;a magnetic field generator to generate a substantially uniform magnetic field with field lines extending from a first end of the first evacuated region to a second end of the first evacuated region;an energizing beam source to generate a pulsed beam along an axis of the first evacuated region at a cyclotron frequency corresponding to a mass and charge of an individual chargeable particle of the first plurality of chargeable particles;a first confinement electrode to confine particles in a first direction along the axis of the first evacuated region; anda second confinement electrode to confine particles in a second direction along the axis of the first evacuated region such that particles are axially confined between the first confinement electrode and the second confinement electrode,wherein the magnetic field causes charged particles within the first evacuated region to move in a circular trajectory, and thereby radially confines the particles within the first evacuated region for at least particle velocities less than a velocity required for fusion of the particles. 19. The fusion reactor of claim 18, further comprising:a second evacuated region positioned proximate to and axially aligned with the first evacuated region to share the second confinement electrode,wherein the field lines of the substantially uniform magnetic field extend from a first end of the second evacuated region to a second end of the second evacuated region;a second plurality of chargeable particles positioned within the second evacuated region; anda third confinement electrode to confine particles in the second direction, such that the second plurality of chargeable particles are axially confined between the second confinement electrode and the third confinement electrode within the second evacuated region,wherein the pulsed beam from the energizing beam source to extend through the first evacuated region and through the second evacuated region along an axis of the second evacuated region. 20. The fusion reactor of claim 19, wherein at least one of the first, second, and third confinement electrodes comprises a ring electrode.
043839444	description	EXAMPLE Glass balls less than 2 mm in diameter were mixed with lead powder which was sedimentatively matched by way of a determination of its powder characteristic (e.g. particle size and shape, chemical composition, microstructure and particle density), i.e. the mixing was done in a liquid whose viscosity was variable as for example glycerin and alcohol in variable concentrations. The suspension of glass and lead in liquid was disposed in a mixing vessel which was moved in a tumbling mixer for about 3 hours, until a macroscopically homogeneous distribution of the two powders in the suspension had been achieved. Due to the sedimentatively matched similar sinking speeds, this distribution remained the same even after the powders settled in the suspension. The liquid was next evaporated at sufficiently low temperatures to avoid oxidation of the lead, which was minimized. The mixture was then pressed in steel molds at about 100 Newtons/mm.sup.2 compression pressure avoiding excessive pressure which would cause the resulting molded balls to burst. Finally, the pressed mixture was sintered at about 400.degree. K. for about 5 hours. In this example, the mixing ratio of volume of lead : volume of glass was equal to 7:1. The strength of the resulting molded bodies was good, and their diameter was 2 cm. It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.
060581549	abstract	A sealable metal multipurpose canister for confining irradiated nuclear fuel assemblies and a sealing means therefor. The canister includes a tubular or cylindrical body having a vertical major axis and vertical wall, a lower end closed by a welded base and an open and sealable upper end having a vertical inner wall section including a transverse shoulder extending over at least a portion of the vertical inner wall. The sealing means includes a first solid metal sealing disk supported by the transverse shoulder and having a peripheral portion cooperating sealingly with the vertical inner wall, a second solid metal sealing disk resting on and above the first sealing disk and having a peripheral portion cooperating sealingly with the vertical inner wall and a gripping means located inside the upper end above the second sealing disk, and acting on the first and second sealing disks to create a leaktight seal.
	claims	1. method for electrodepositing Co and Fe, comprising:separating an anode chamber provided with an anode from a cathode chamber provided with a cathode by a cation exchange membrane,supplying a liquid containing Co ions and Fe ions and having pH 1 or less into the anode chamber,supplying a liquid containing at least one additive selected from a dicarboxylic acid and a salt thereof and a tricarboxylic acid and a salt thereof, each of which is represented by the following formula (1), into the cathode chamber, andapplying a voltage between the anode and the cathode, so that the Co ions and the Fe ions in the liquid in the anode chamber are moved into the liquid in the cathode chamber through the cation exchange membrane, and Co and Fe are precipitated on the cathode:M1OOC—(CHX1)a—(NH)b—(CX2X4)c—CX3X5—COOM2 (1)where, in the formula (1),X1, X2, and X3 each independently represent H or OH,X4 and X5 each independently represent H, OH, or COOM3,M1, M2, and M3 each independently represent H, a monovalent alkali metal, or an ammonium ion,a, b, and c each independently represent an integer of 0 or 1, andX4 and X5 do not simultaneously represent COOM3. 2. The method for electrodepositing Co and Fe according to claim 1, wherein the dicarboxylic acid is at least one selected from malonic acid, succinic acid, malic acid, tartaric acid, and iminodiacetic acid. 3. The method for electrodepositing Co and Fe according to claim 1, wherein the tricarboxylic acid is citric acid. 4. The method for electrodepositing Co and Fe according to claim 1, further comprising supplying an ammonium salt along with the liquid containing the at least one additive. 5. The method for electrodepositing Co and Fe according to claim 4, wherein the ammonium salt is at least one selected from ammonium chloride, ammonium sulfate, and ammonium oxalate. 6. The method for electrodepositing Co and Fe according to claim 4, further comprising supplying a liquid containing sulfuric acid or oxalic acid to the liquid containing the Co ions and the Fe ions,wherein a concentration of the ammonium salt in the liquid containing the Co ions and the Fe ions is 0.01 to 20 percent by weight,an acid concentration of the sulfuric acid in the liquid containing the Co ions and the Fe ions is 5 to 40 percent by weight, andan acid concentration of the oxalic acid in the liquid containing the Co ions and the Fe ions is 0.1 to 40 percent by weight. 7. The method for electrodepositing Co and Fe according to claim 1, wherein the tricarboxylic acid is ammonium citrate. 8. An apparatus for electrodepositing Co and Fe, comprising:an electrodeposition bath which includes an anode chamber provided with an anode, a cathode chamber provided with a cathode, and a cation exchange membrane separating the anode chamber from the cathode chamber;a voltage applicator for applying a voltage between the anode and the cathode;a liquid passer for allowing a liquid containing Co ions and Fe ions and having pH 1 or less to pass through the anode chamber; anda liquid passer for allowing a liquid containing at least one additive selected from a dicarboxylic acid and a salt thereof and a tricarboxylic acid and a salt thereof, each of which is represented by the following formula (1),wherein by applying the voltage between the anode and the cathode, the Co ions and the Fe ions in the liquid in the anode chamber are moved into the liquid in the cathode chamber through the cation exchange membrane, and Co and Fe are precipitated on the cathode:M1OOC—(CHX1)a—(NH)b—(CX2X4)c—CX3X5—COOM2 (1)where, in the formula (1),X1, X2, and X3 each independently represent H or OH,X4 and X5 each independently represent H, OH, or COOM3,M1, M2, and M3 each independently represent H, a monovalent alkali metal, or an ammonium ion,a, b, and c each independently represent an integer of 0 or 1, andX4 and X5 do not simultaneously represent COOM3. 9. The apparatus for electrodepositing Co and Fe according to claim 8, wherein the dicarboxylic acid is at least one selected from malonic acid, succinic acid, malic acid, tartaric acid, and iminodiacetic acid. 10. The apparatus for electrodepositing Co and Fe according to claim 8, wherein the tricarboxylic acid is citric acid. 11. The apparatus for electrodepositing Co and Fe according to claim 8, wherein the liquid containing the at least one additive further contains an ammonium salt. 12. The apparatus for electrodepositing Co and Fe according to claim 11, wherein the ammonium salt is at least one selected from ammonium chloride, ammonium sulfate, and ammonium oxalate. 13. The apparatus for electrodepositing Co and Fe according to claim 11, further comprising a storage bath storing a liquid containing sulfuric acid or oxalic acid supplied to the anode chamber,wherein a concentration of the ammonium salt in the liquid containing the Co ions and the Fe ions is 0.01 to 20 percent by weight,an acid concentration of the sulfuric acid in the liquid containing the Co ions and the Fe ions is 5 to 40 percent by weight, andan acid concentration of the oxalic acid in the liquid containing the Co ions and the Fe ions is 0.1 to 40 percent by weight. 14. The apparatus for electrodepositing Co and Fe according to claim 8, wherein the tricarboxylic acid is ammonium citrate.
	claims	1. A method for monitoring performance and determining the maintenance needs of an electromechanical system comprising the steps of:monitoring a plurality of predetermined system conditions;collecting monitored values of the plurality of said predetermined system conditions over time by steps including recording a plurality of monitored values representing each monitored predetermined system condition and the time of occurrence for each said recorded monitored value;calculating system maintenance needs from said collected monitored values by steps including comparing said collected monitored values representing a monitored system condition with a predetermined threshold value for said monitored system condition and determining whether a maintenance procedure is necessary to maintain the mechanical performance of said monitored system condition within predetermined limits; andwhere determined to be necessary initiating a maintenance procedure to maintain the mechanical performance of said monitored system condition within predetermined limits. 2. The method of claim 1, wherein said step of calculating includes the steps of:summing said recorded monitored values representing a monitored system condition; andcomparing a resulting sum of said recorded monitored values representing a monitored system condition against said predetermined threshold value for said monitored system condition to determine whether a maintenance procedure is necessary to maintain the mechanical performance of said monitored system condition within predetermined limits. 3. The method of claim 2, wherein said step of summing uses said recorded monitored values in accordance with their respective time of occurrence. 4. The method of claim 3, wherein said step of summing includes weighting said recorded monitored values in accordance with their respective predetermined system condition. 5. The method of claim 3, wherein said step of comparing includes weighting either said resulting sum or said threshold value in accordance with said respective time of occurrence. 6. The method of claim 5, wherein said recorded monitored values having a more recent time of occurrence are given a higher weight than said recorded monitored values having a less recent time of occurrence. 7. The method of claim 2 wherein said step of summing uses said recorded monitored values in accordance with their respective predetermined system condition. 8. The method of claim 7, wherein said step of summing includes weighting said recorded monitored values in accordance with their respective time of occurrence. 9. The method of claim 7, wherein said step of comparing includes weighting either said resulting sum or said threshold value in accordance with said predetermined respective system condition. 10. The method of claim 2, wherein said step of summing uses said recorded monitored values which indicate an error in their respective monitored system condition. 11. The method of claim 2, wherein said step of calculating uses recorded monitored values from a predetermined amount of most recent operation of said electromechanical system. 12. The method of claim 11, wherein said step of calculating divides said predetermined amount of most recent operation into sequential segments and weights recorded monitored values from more recent segments higher than recorded monitored values from less recent segments. 13. The method of claim 12, wherein said step of calculating substantially excludes periods of inactivity of said electromechanical system from said predetermined amount of most recent operation. 14. A system for monitoring performance and determining the maintenance needs of an electromechanical system having a plurality of monitored system conditions, comprising:a recording apparatus adapted for collecting and recording over time, a plurality of monitored values for each of the plurality of monitored system conditions along with a time of occurrence for each recorded value;a calculating system adapted for calculating system maintenance needs from said plurality of recorded monitored values representing each monitored system condition and their respective time of occurrence; andan output signal generating system for initiating a maintenance procedure to maintain the mechanical performance of said monitored system within predetermined limits. 15. The system of claim 14, wherein said calculating system includes:an adder adapted for summing said recorded monitored values representing a monitored system condition; anda comparator adapted for comparing a resulting sum of said monitored values representing a monitored system condition from said adder against a predetermined threshold value to determine whether to generate an output signal to initiate a maintenance procedure. 16. The system of claim 15, wherein said recorded monitored values are selected in accordance with their respective times of occurrence, and further wherein said resulting sum or said threshold value is weighted in accordance with said respective time of occurrence. 17. The system of claim 16, further comprising a multiplier adapted for weighting said recorded monitored values in accordance with their respective system conditions prior to summing by said adder. 18. The system of claim 14, wherein the electromechanical system is a printing apparatus. 19. A system for determining maintenance needs of a printer apparatus having a plurality of monitored conditions, comprising:a recording process adapted for collecting and recording over time, a plurality of monitored values for each of the plurality of monitored conditions along with a time of occurrence for each recorded value;a calculating process adapted for using said plurality of recorded monitored values and the time of occurrence of said values for calculating system maintenance needs by steps including comparing said collected monitored values representing a monitored condition with a predetermined threshold value for said monitored condition and determining whether a maintenance procedure is necessary to maintain the mechanical performance of said monitored condition within predetermined limits; andan output signal generating process adapted to generate an output signal to initiate a maintenance procedure to maintain the mechanical performance of said monitored condition of said printing apparatus within predetermined limits. 20. The system of claim 19, wherein said calculating process includes:an adder process adapted for summing selected types of said recorded values; anda comparator process adapted for comparing a resulting sum from said adder process against a predetermined threshold value to determine maintenance needs of said printing apparatus. 21. The system of claim 20, wherein said recorded values are selected for said adder process in accordance with their respective times of occurrence, and further wherein said resulting sum or said threshold value is weighted in accordance with said respective time of occurrence. 22. The system of claim 21, further comprising a multiplier process adapted for weighting the selected recorded values in accordance with their respective monitored conditions prior to summing by said adder process. 23. The system of claim 20, wherein said recorded values are selected for said adder process in accordance with their respective monitored conditions, and further wherein said resulting sum or said threshold value is weighted in accordance with said respective monitored condition. 24. The system of claim 23, further comprising a multiplier process adapted for weighting the selected recorded values in accordance with their respective time of occurrence prior to summing by said adder process. 25. The system of claim 19, wherein said calculating process is adapted for using recorded values which indicate an error with their respective monitored conditions. 26. The system of claim 19, wherein said calculating process is adapted to use recorded values from a predetermined amount of most recent operation of said printing apparatus. 27. The system of claim 26, wherein said calculating process divides said predetermined amount of most recent operation of said printing apparatus into sequential segments and weights recorded values from more recent segments higher than recorded values from less recent segments. 28. The system of claim 27, wherein said calculating process substantially excludes periods of inactivity of said printing apparatus from said predetermined amount of most recent operation.
	abstract	A charged particle beam drawing apparatus forms a map having meshes, forms representative figures, area of each representative figure in each mesh being equal to gross area of figures in each mesh, and calculates a proximity effect correction dose of the charged particle beam in each mesh on the basis of area of each representative figure in each mesh. If it is necessary to change the proximity effect correction dose of the charged particle beam for drawing at least one pattern corresponding to at least one figure, the charged particle beam drawing apparatus changes area of the at least one figure before the representative figures are formed by a representative figure forming portion, and changes the proximity effect correction dose of the charged particle beam for drawing the at least one pattern corresponding to the at least one figure, calculated by a proximity effect correction dose calculating portion.
	description	This application claims priority from Japanese Patent Application P2007-067043, filed on Mar. 15, 2007. The entire content of the aforementioned application is incorporated herein by reference. 1. Field of the Invention The present invention relates to an X-ray examination apparatus and an X-ray examination method using the same. 2. Description of the Related Art Recently, with high integration of an LSI (Large-Scale Integration) by submicron microfabrication technique, functions which were divided into a plurality of packages in the prior art can now be integrated into one LSI. Since increase in the number of pins that arise as a result of incorporating the functions necessary for one package cannot be responded with the conventional QFP (Quad Flat Package) and PGA (Pin Grid Array), LSI of BGA (Ball Grid Array) and CSP (Chip Size Package) package, in particular, is recently being used. The BGA package is used where ultraminiaturization is necessary such as a portable telephone even if the required number of pins is not great. The BGA and CSP package of the LSI greatly contribute to ultraminiaturization, but has a feature in that the solder portion etc. cannot be seen from the outer appearance after assembly. When inspecting a print substrate etc. mounted with the BGA or CSP package, the quality determination is performed by analyzing a transmissive image obtained by irradiating an X-ray onto an examining object. For instance, patent document 1 (refer to, for example, Japanese Patent Application Laid-Open Publication No. 2000-46760) discloses an X-ray sectional examination apparatus capable of obtaining a clear X-ray image by using an X-ray planar sensor to detect the transmissive X-ray. In such an X-ray examination apparatus, the X-ray is emitted by impinging the electron beam onto a target such as tungsten. When the electron beam impinges the target, the target is damaged. Thus, the target deteriorates if the electron beam is impinged on the same position of the target for greater than or equal to a predetermined time. The X-ray source of the X-ray examination apparatus includes a method in which a position of impinging the electron beam onto the target is fixed (fixed focus method), and a method in which the electron beam is repeatedly impinged onto a predetermined position in a discrete manner. Longer lifespan can be expected in the latter method than in the fixed focus method but the target similarly deteriorates. When the target deteriorates, maintenance of the target needs to be carried out as the irradiated X-ray amount decreases and the X-ray image becomes dark, or the image quality lowers and the examination efficiency degrades. The deterioration of the target is limited to a small portion where the electron beam impinges, and thus the user performs the maintenance of the target by rotating the target surface. The position where the electron beam impinges shifts from the deteriorated position, and characteristics similar to a new target can be obtained. For instance, when performing the X-ray examination using Micro-focus X-ray source L9191 manufactured by Hamamatsu Photonics K. K., the user carries out the maintenance of the target by manually rotating the target surface. Generally, the lifetime of the target of the transmissive X-ray source is between about 300 hours to 500 hours. If the frequency of use is small as with an analyzer, the period until the target deteriorates is long and the trouble necessary for carrying out the maintenance of the target will not be a problem. However, if operated for a long period of time as with an in-line examination apparatus, the period until the target deteriorates is short, and thus it is important that the maintenance of the target is easy and convenient to carry out. In a method of carrying out the maintenance by manually rotating the target, the maintenance workman needs to be familiar with the task and the task requires time. Information for maintenance, for example, how long and at which position of the target the X-ray is irradiated need to be managed. In the method of repeatedly using a predetermined position of the target in a discrete manner in the scanning X-ray source, the electron beam is impinged on a plurality of positions, and thus the amount of information for maintenance becomes enormous, and becomes difficult for the user to manage. In view of solving the above problems, it is an object of the present invention to provide an X-ray examination apparatus capable of efficiently using the target surface, and an X-ray examination method using the X-ray examination apparatus applied with an X-ray photographing method of the X-ray examination apparatus. It is another object of the present invention to provide an X-ray examination apparatus capable of reducing the trouble necessary for carrying out maintenance of the X-ray source by uniformly using the target surface of the same target, and an X-ray examination method using the X-ray examination apparatus applied with the X-ray photographing method of the X-ray examination apparatus. One aspect of the present invention relates to an X-ray examination method using an X-ray examination apparatus for examining an examining portion of an object by X-ray irradiation, the apparatus including a detection surface for detecting an intensity distribution of an X-ray set and entered to a position specified out of predetermined positions, an X-ray source capable of moving an X-ray focal position on a target surface and generating the X-ray, and a storage device for storing history information on generation of the X-ray at the position on the target surface as the X-ray focal position, the method including the steps of: setting the X-ray focal position corresponding to a position of the detection surface specified out of a plurality of first predetermined positions and the examining portion; detecting that an X-ray radiation dosage generated from the set X-ray focal position has exceeded a predetermined amount based on the history information of the storage device; changing and setting a specified position of the detection surface to one of a plurality of second predetermined positions different from the plurality of first predetermined positions according to the detection result; moving the X-ray focal position to a position reset according to the changed detection surface, and generating the X-ray; and detecting an intensity distribution of the X-ray transmitted through the examining portion on the detection surface. Preferably, the step of setting the X-ray focal position includes a step of determining the X-ray focal position on the target surface so that the X-ray transmits through the examining portion and enters the detection surface. Preferably, the step of changing and setting the specified position includes a step of specifying a plurality of detection surfaces for detecting the X-ray out of the plurality of second predetermined positions; the step of generating the X-ray includes steps of: determining each of the plurality of X-ray focal positions on the target surface so that the X-ray transmits through the examining portion and enters the plurality of detection surfaces, and moving an irradiating position applied with an electron beam of the X-ray source to the each determined X-ray focal position, and generating the X-ray; and the method further includes a step of: reconstructing image data of the examining portion based on data of the detected intensity distribution. Preferably, the step of detecting that the X-ray radiation dosage has exceeded the predetermined amount includes a step of detecting that at least an accumulated time in which the X-ray is generated from the set X-ray focal position has elapsed a predetermined time. Preferably, the step of determining each of the plurality of X-ray focal positions includes a step of determining the X-ray focal position excluding a position applied with the electron beam beyond the predetermined time. Preferably, the step of determining each of the plurality of X-ray focal positions includes a step of determining the X-ray focal position out of a position applied with the electron beam beyond the predetermined time excluding a range determined based on an area coefficient corresponding to a size of an X-ray focus. Preferably, the step of generating the X-ray includes a step of changing an irradiation position applied with an electron beam on the target surface by deflecting the electron beam, and moving the X-ray focal position. Another aspect of the present invention relates to an X-ray examination apparatus for examining an examining portion of an object with X-ray, the X-ray examination apparatus including: an X-ray detector having a plurality of detection surfaces for detecting the X-ray, the X-ray detector including a detection position changing part for changing the positions of the plurality of detection surfaces from a plurality of first predetermined positions to a plurality of second predetermined positions different from the plurality of first predetermined positions; an output controller for controlling an output process of the X-ray, the output controller including: a starting point setting part for setting, on the plurality of detection surfaces, each starting point of X-ray emission so that the X-ray transmits through the examining portion of the object and enters the each detection surface, a storage part for storing the each starting position and history information on emission of the X-ray from the each starting position in correspondence to each other, and a detection part for detecting that an accumulated irradiation time has elapsed a predetermined time on the set starting point position based on the history information in the storage part, and outputting the detection result to allow the detection position changing part to change, the starting point setting part resets the each starting point position when change is made by the detection position changing part, the apparatus further including: an X-ray output part for moving an X-ray focal position of an X-ray source to the each starting position and generating the X-ray; and a reconstruction part for reconstructing image data of the examining portion based on data of an intensity distribution of the X-ray transmitted through the examining portion detected on the plurality of detection surfaces. Preferably, the X-ray output part includes a part for deflecting an electron beam and moving an irradiation position on the target surface to move the X-ray focal position. Preferably, the detection position changing part includes: a rotatable base arranged with the plurality of detection surfaces on a circumference having a predetermined axis as a center; and a rotating part for rotating the rotatable base with the axis as the center; wherein the positions of the plurality of detection surfaces are changed from the plurality of first predetermined positions to the plurality of second predetermined positions by rotating the rotatable base by a constant angle according to the detection result of the detection part. Preferably, the starting point setting part sets the each starting point position excluding the position associated with an irradiation time that has elapsed the predetermined time based on the history information. Preferably, the output part further includes a specifying part for specifying an examining portion of the object. According to the X-ray examination apparatus and the examination method of the X-ray examining apparatus of the present invention, the target surface can be efficiently used. Embodiments of the present invention will be described with reference to the drawings. In the following description, same reference numerals are denoted for the same components. The names and the functions thereof are also the same. Therefore, detailed description thereon will not be repeated. (1. Configuration of the Present Invention) FIG. 1 shows a schematic block diagram of an X-ray examination apparatus 100 according to the present invention. The X-ray examination apparatus 100 according to the present invention will be described with reference to FIG. 1. It should be noted that configuration, dimension, shape, and other relative arrangements described below do not intend to exclusively limit the scope of the invention thereto unless specifically stated. The X-ray examination apparatus 100 includes a scanning X-ray source 10 for outputting X-rays, and a sensor base 22 being attached with a plurality of X-ray sensors 23 and being a rotatable base that rotates with a rotation axis 21 as a center. An examining target 20 is arranged between the scanning X-ray source 10 and the sensor base 22. The X-ray examination apparatus 100 also includes an image acquiring control mechanism 30 for controlling acquisition of rotation angle about the rotation axis of the sensor base 22 and image data from the X-ray sensor 23; an input unit 40 for accepting instruction input etc. by a user; and an output unit 50 for outputting measurement result etc. to the outside. The X-ray examination apparatus 100 furthermore includes a scanning X-ray source control mechanism 60, a calculation unit 70, and a memory 90. In such a configuration, the calculation unit 70 executes a program (not shown) stored in the memory 90 to control each unit, and performs a predetermined calculation process. The scanning X-ray source 10 is controlled by the scanning X-ray source control mechanism 60, and irradiates X-rays to the examining target 20. FIG. 2 shows a cross sectional view showing a configuration of the scanning X-ray source 10. With reference to FIG. 2, an electron beam 16 is irradiated to a target 11 such as tungsten from an electron gun 15 controlled by an electron beam controller 62 in the scanning X-ray source 10. An X-ray 18 is generated at a site (X-ray focal position 17) where the electron beam 16 impinges the target, and is emitted (output). The electron beam system is accommodated in a vacuum container 9. The inside of the vacuum container 9 is maintained in vacuum by a vacuum pump 14, and the electron beam 16 accelerated by a high voltage power supply 13 is emitted from the electron gun 15. In the scanning X-ray source 10, the site where the electron beam 16 impinges the target 11 can be arbitrarily changed by deflecting the electron beam 16 by means of a deflection yoke 12. For instance, an electron beam 16a deflected by the deflection yoke 12 impinges the target 11, and an X-ray 18a is output from an X-ray focal position 17a. Similarly, an electron beam 16b deflected by the deflection yoke 12 impinges the target 11, and an X-ray 18b is output from an X-ray focal position 17b. In the present invention, the scanning X-ray source 10 is of a transmissive type, and a target not in a ring shape but a target having a continuous surface is desirable so that, when generating the X-ray from a position (hereinafter referred to as “starting position of X-ray emission”) to become the starting position of X-ray emission set according to the examining target portion of the examining object, the degree of freedom in setting such a position can be enhanced, as hereinafter described. In the following description, the position is simply referred to as the X-ray focal position 17 as a collective term unless the position is particularly distinguished. The position of the X-ray source itself can also be mechanically moved each time when moving the X-ray focal position to the each starting position of X-ray emission. However, with the configuration shown in FIG. 2, when moving the X-ray focal position to the starting position of X-ray generation within a constant range, the X-ray source does not need to be mechanically moved, whereby it is possible to realize an X-ray examination apparatus excelling in maintenance and reliability. Alternatively, a plurality of X-ray sources may be arranged so as to be switched in time of use according to the starting position. The size of the X-ray focus formed when the electron beam 16 impinges the target 11 is generally from one sub-micron to a few hundred microns. When the electron beam impinges the same position of the target 11 for greater than or equal to a predetermined time, the relevant position and a predetermined range with such a position as the center deteriorate through thermal damage and the like. When the X-ray focal position deteriorates, the irradiated X-ray amount decreases and the X-ray image becomes darker, or the image quality lowers and the examination efficiency degrades. In the method of the prior art, the target 11 itself is rotated etc. so that the target of the X-ray focal position has the same characteristics as the new target in order to prevent lowering in image quality etc. However, this method takes time in the rotation task and needs to interrupt the X-ray examination. In the present invention, the position of each X-ray sensor 23 is changed, and the starting position of X-ray emission that becomes the X-ray focal position 17 is newly set so that the X-ray enters each X-ray sensor 23 after the position is changed. The scanning X-ray source 10 according to the present invention deflects the electron beam 16 to easily change the position the electron beam 16 impinges the target 11 to an arbitrary location, and thus the irradiating position of the electron beam can be moved according to an accumulative irradiation time on the target 11, and the maintenance of the target can be carried out without interrupting the X-ray examination. Returning back to FIG. 1, the scanning X-ray source control mechanism 60 includes an electron beam controller 62 for controlling the output of the electron beam. The electron beam controller 62 receives a specification of X-ray focal position, X-ray energy (tube voltage, tube current) from the calculation unit 70. The X-ray energy differs depending on the configuration of the examining target. The examining target 20 is arranged between the scanning X-ray source 10 and the X-ray sensor 23 (sensor base 22). The examining target 20 may be moved to an arbitrary position in X-Y-Z stage, or may be arranged at a position for examination by moving in one direction like a belt conveyor. If the examining target is small as in print mounting substrate, the examining target is moved with the scanning X-ray source 10 and the sensor base 22 fixed, but if the examining target is difficult to be arbitrarily moved since the examining target such as a glass substrate has a large area, the scanning X-ray source 10 and the sensor base 22 are moved with the relative position of the scanning X-ray source 10 and the sensor base 22 fixed. The X-ray sensor 23 is a two-dimensional sensor for detecting and imaging an X-ray output from the scanning X-ray source 10 and transmitted through the examining target 20. The X-ray sensor 23 may be a CCD (Charge Coupled Device) camera, I.I. (Image intensifier) tube, and the like. In the present invention, an FPD (Flat Panel Display) having satisfactory space efficiency is desirable since a plurality of X-ray sensors is arranged in the sensor base 22. High sensitivity is also desirable so that use can be made in an in-line examination, and the FPD of direct conversion method using CdTe is particularly desirable. In the following description, the sensor is simply referred to as the X-ray sensor 23 as a collective term unless the sensor is particularly distinguished. In the sensor base 22, the plurality of X-ray sensors 23 are attached on a circumference of the rotatable base on the scanning X-ray source 10 side. The sensor base 22 can rotate with the rotation axis 21 of the rotatable base as the center. Actually, the rotatable range only needs to be less than or equal to one rotation, and when N X-ray sensors are arranged on the circumference of the sensor base 22, the angle formed by the adjacent X-ray sensors and the center of rotation of the sensor base only needs to rotate about 360/N. Obviously, this equation is merely one specific example, and the rotation angle is not limited by such an equation. The rotation angle of the sensor base 22 is known by a sensor (not shown), and is retrieved to the calculation unit 70 via the input unit 40. The sensor base 22 is desirably raised and lowered in the up and down direction to adjust the scale of enlargement. In this case, the position of the sensor base 22 in the up and down direction is known by a sensor (not shown), and is retrieved to the calculation unit 70 by the input unit 40. The angle of the X-ray entering the X-ray sensor 23 changes when the sensor base 22 is raised and lowered in the up and down direction, and thus the inclination angle with respect to the sensor base 22 of the X-ray sensor 23 is desirably controllable. The image acquiring control mechanism 30 includes a rotation angle controller 32 for performing a control so that the sensor base rotates at an angle specified by the calculation unit 70, and an image data acquiring part 34 for acquiring image data of the X-ray sensor 23 specified by the calculation unit 70. The X-ray sensor specified by the calculation unit 70 may be one or may be in plurals. The input unit 40 is an operation input equipment for accepting input of a user. The output unit 50 is a display for displaying X-ray image etc. configured with the calculation unit 70 and information for maintenance of the target. That is, the user executes various inputs through the input unit 40, and various calculation results obtained by the processes of the calculation unit 70 are displayed on the output unit 50. The image displayed on the output unit 50 may be output for visible quality determination by the user or may be output as quality determination result of a quality determination part 78 to be hereinafter described. The calculation unit 70 includes a scanning X-ray source controller 72, an image acquiring controller 74, a 3D image reconstruction part 76, a quality determination part 78, a stage controller 80, an X-ray focal position calculating part 82, an imaging condition setting part 84, and a maintenance information managing part 86. The scanning X-ray source controller 72 determines the X-ray focal position and the X-ray energy, and sends a command to the scanning X-ray source control mechanism 60. The image acquiring controller 74 determines a rotation angle of the sensor base 22 and the X-ray sensor 23 to acquire the image, and sends a command to the image acquiring control mechanism 30. The image is acquired from the image acquiring control mechanism 30. The 3D image reconstruction part 76 reconstructs three-dimensional data based on a plurality of data acquired by the image acquiring controller 74. The quality determination part 78 determines the quality of the examining target based on 3D image data reconstructed by the 3D image reconstruction part 76 or perspective data. For instance, quality determination can be performed by recognizing the shape of a solder ball, and determining whether or not the shape is within a tolerable range defined in advance. An algorithm for performing quality determination or input information to the algorithm differ depending on the examining target and are available from the imaging condition information 94. The stage controller 80 controls a mechanism (not shown) for moving the examining target 20. The X-ray focal position calculating part 82 calculates the X-ray focal position, irradiation angle, and the like with respect to an examination area when examining a certain examination area of the examining object 20. The details thereof will be hereinafter described. The imaging condition setting part 84 sets the conditions for a case of outputting the X-ray from the scanning X-ray source 10 according to the examining target 20. The conditions include an application voltage on the X-ray tube, and imaging time. The maintenance information managing part 86 accumulates the time the electron beam is irradiated onto the target surface, and determines the X-ray focal position where the accumulative irradiation time has elapsed a predetermined threshold value (time representing lifetime of target) as a focal position that cannot be used as the starting position of X-ray emission. The lifetime of the target is notified to the user through alarm display etc. via the output unit 50. In the present embodiment, the lifetime of the target is determined with the irradiation time of the electron beam by way of example, but may be determined by the user by looking at the perspective image, or more generally, determined based on the X-ray generation amount. The lifetime of the target can be determined based on the X-ray generation amount with a method of assuming the intensity of the X-ray as a group of X-ray photons, or a method of analyzing the number of X-ray photons and the energy thereof. In the method of assuming the intensity of the X-ray as a group of photons, the decreasing rate of dosage (integrated dosage μSV, dosage per hour μSv/h) is determined using a dosemeter such as an ionization chamber. In the method of analyzing the number of X-ray photons and energy thereof, a profile of the X-ray generation amount in a desired target state (not reaching lifetime) (e.g., horizontal axis is energy of X-ray photon, vertical axis is number of photons) is obtained using a semiconductor X-ray detector etc., and determination is made based on change in the profile. For instance, determination is made that the lifetime is over when a shift amount exceeds a certain threshold value or when the decreasing rate of intensity (the number of photons) of the X-ray energy, which is important in examination, exceeds a threshold value. The memory 90 includes X-ray target maintenance information 91 storing information provided by the maintenance information managing part 86, X-ray focal position information 92 storing information related to the X-ray focal position calculated by the X-ray focal position calculating part 82, and imaging condition information 94 storing imaging condition set by the imaging condition setting part 84 and algorithm for performing quality determination. The X-ray target maintenance information 91 includes currently used target maintenance information in which the X-ray focal position currently being used in imaging and the accumulated X-ray irradiation time or the accumulation of the time the electron beam is irradiated on the X-ray focal position are corresponded to each other, previously used target maintenance information in which the X-ray focal position used in the past in imaging and the accumulated X-ray irradiation time of the X-ray focal position are corresponded to each other, and NG target maintenance information indicating the position of the target surface that cannot be used as the X-ray focal position. The X-ray target maintenance information 91 contains an area coefficient D corresponding to the size of the X-ray focus. As mentioned above, the size of the X-ray focus is generally one sub-micron to a few hundred microns, but actually, the surrounding area of the focus size is also subjected to damages such as thermal damage. The area coefficient D is thus set. The maintenance information managing part 86 determines a range of diameter D or diagonal D with the X-ray focal position as the center as the portion that is subjected to damage in the target and that cannot be used (lifetime is over) as the focal position of the X-ray. With respect to each examination area, the X-ray focal position information 92 is associated with the calculation result (focal position, irradiation angle, sensor imaging angle, sensor arrangement angle, sensor inclination angle, etc. with respect to each X-ray sensor 23) calculated by the X-ray focal position calculating part 82. This will be hereinafter specifically described. The memory 90 merely needs to be able to store data, and is configured by storage devices such as a RAM (Random Access Memory) and an EEPROM (Electrically Erasable and Programmable Read-Only Memory). FIG. 3 shows a view of the sensor base 22 when seen from the scanning X-ray source 10 side. In particular, FIG. 3A shows a view in which the X-ray sensors 23 arranged on the same radius, and FIG. 3B shows a view in which the X-ray sensors 23 are arranged on different radii. The sensor base 22 will be described with reference to FIG. 3. A plurality of X-ray sensor modules 25 in which a mechanism component for performing data processing etc. is compounded to the X-ray sensor 23 is attached to the sensor base 22. The X-ray sensor module 25 may be arranged so that the X-ray sensor 23 is on the circumference of the same radius of a circle having the center of rotation of the sensor base as a center, as shown in FIG. 3A, or may be arranged on a circumference of different radii, as shown in FIG. 3B. The sensor module 25 is desirably also arranged at the center of the sensor base 22. The X-ray sensor module 25 is desirably controlled so as to be freely movable in a radial direction by way of a slider 24. The imaged data of the examining target when seen from various degrees then can be acquired. FIG. 4 shows a side view showing the X-ray sensor module 25. A view of the X-ray sensor 23 when seen from an X-ray receiving part 26 side is also shown. The X-ray sensor module 25 will be described with reference to FIG. 4. The X-ray sensor module 25 includes the X-ray receiving part 26 for converting the X-ray to an electrical signal, and a data processing part 29 for creating data of the electrical signal and transmitting the data to the image data acquiring part 34 through a data cable 27. Power is externally supplied to the X-ray sensor module 25 via a power supply cable 28. The X-ray sensor module 25 can be freely moved in a radial direction by way of the slider 24, but may be fixed at a position. The X-ray sensor 23 is inclined by a constant angle (sensor inclination angle α) with respect to the sensor base 22. In FIG. 4, the sensor inclination angle α is fixed, but angular adjustment may be carried out according to the control by the image acquiring control mechanism 30. The plurality of X-ray sensor modules 25 are attached to the sensor base 22, but are respectively removable. Therefore, only the damaged X-ray sensor module can be replaced. FIG. 5 shows a conceptual view of an imaging system seen from the side. The imaging system will be described with reference to FIG. 5. In FIG. 5, the X-ray sensors 23a, 23b may be any X-ray sensor 23 as long they are in an opposing position relationship. In FIG. 5, the X-ray sensors 23a, 23b are respectively inclined by a constant angle (sensor inclination angle αA, αB) with respect to the sensor base 22. Suppose a distance Z1 is from the target surface of the scanning X-ray source 10 to the examining target 20, and distance Z2 is from the examining target 20 to the X-ray sensor 23. In FIG. 5, a work 130 is on the rotation axis of the sensor base 22. When imaging the work 130, a position (starting position of X-ray emission) at which the focal position (irradiating position of electron beam) of the X-ray output from the scanning X-ray source 10 to the X-ray sensor 23 is to be set is determined. For instance, an X-ray focal position 17a with respect to the X-ray sensor 23a is set at an intersection of a line connecting the sensor center 140 of the X-ray sensor 23a and the center of the work (examination area) 130 and the target surface of the scanning X-ray source 10. A perspective image 142 of the work is detected at the sensor center 140. That is, the starting position of X-ray emission is set such that the X-ray transmits through the work and enters the detection surface with respect to the detection surface of the corresponding X-ray sensor. Therefore, the sensor center 140 of the X-ray sensor 23a, the center of the work 130, and the X-ray focal position 17a are desirably lined on the same line, but the arrangement is not limited to such an arrangement as long the X-ray enters within a constant range of the detection surface. Suppose an angle formed by the line connecting the X-ray sensor 23 and the X-ray focal position 17 and the target surface of the scanning X-ray source 10 is an irradiation angle θ. For instance, the irradiation angles θA, θB are formed with respect to the X-ray sensors 23a, 23b, respectively. The angle is simply referred to as irradiation angle θ unless each irradiation angle is particularly distinguished. As shown in FIG. 5, when the works exists on a perpendicular line of the center of rotation of the sensor base, the irradiation angle θ for all the X-ray sensors 23 becomes equal. In the present invention, the work does not need to be on the center of rotation of the sensor base, and thus each irradiation angle is not necessarily equal to each other. FIG. 6 shows a view describing the sensor arrangement angle and a sensor base reference angle. In particular, FIG. 6A shows a view of before the sensor base is rotated, and FIG. 6B shows a view of after the sensor base is rotated by θs. The sensor arrangement angle and the sensor base reference angle will be described with reference to FIG. 6. In FIG. 6, the X-ray sensors 23a, 23b, 23c may be any X-ray sensor 23 as long as a relationship in which the X-ray sensors 23a, 23b are arranged so as to be adjacent to the X-ray sensor 23b on the circumference of the sensor 22 is obtained. As shown in FIG. 6A, a sensor base reference axis 140 that acts as a reference when indicating the position relationship with respect to the X-ray sensors 23 is defined in the sensor base 22. Here, an axis connecting the X-ray sensor 23a and the sensor 22 is the sensor base reference axis 140. Suppose an angle formed by the X-ray sensor 23 and the sensor base reference axis 140 is the sensor arrangement angle γ. For instance, the sensor arrangement angles γB, γC are formed with respect to the X-ray sensors 23b, 23c, respectively. The angle is simply referred to as sensor arrangement angle γ unless each sensor arrangement angle is particularly distinguished. As shown in FIG. 6B, suppose an axis corresponding to a position of the sensor base reference axis 140 in FIG. 6A is a reference coordinate axis 142. The reference coordinate axis 142 is an axis that becomes a reference when rotating the sensor base 22 for imaging. An angle formed by the reference coordinate axis 142 and the sensor base reference axis 140 is the sensor base reference angle θs. In the case of FIG. 6A, the sensor reference angle is zero degrees. FIG. 7 shows a view describing a target maintenance angle. In particular, FIG. 7A shows a view of after the reference coordinate axis is rotated by θm with respect to a mechanical coordinate system, and FIG. 7B shows a view of after the sensor base reference angle is rotated by θs with respect to the reference coordinate axis. The target maintenance angle will now be described with reference to FIG. 7. As shown in FIG. 7A, a mechanical coordinate system 141, which is a coordinate system fixed in the sensor base 22 and used when indicating an absolute position of each X-ray sensor 23, is defined in the sensor base 22. The mechanical coordinate system 141 acts as a reference when rotating the sensor base 22 to shift the X-ray focal position at the target 11. The angle formed by the reference coordinate axis 142 and the mechanical coordinate system 141 is the target maintenance angle θm. As shown in FIG. 7B, the sensor base reference axis 140 is rotated with respect to the reference coordinate axis 142 when rotating the sensor base 22 for imaging after rotation of target maintenance angle θm. As described above, the angle formed by the reference coordinate axis 142 and the sensor base reference axis 140 is the sensor base reference angle θs. FIG. 8 shows a conceptual view of the imaging system seen from above and from the side, showing an image at rotating the sensor base 22. A view of the scanning X-ray source 10 seen from the sensor base 22 side is also shown. The relationship between the position of the X-ray sensor and the X-ray focal position when the sensor base 22 is rotated will be described with reference to FIG. 8. As shown in FIG. 8, the X-ray focal position with respect to the X-ray sensor 23a is A0 and the X-ray focal position with respect to the X-ray sensor 23b is B0 before the sensor base 22 is rotated. In this case, the X-ray sensors 23a, 23b are at positions of AP0, BP0 when the sensor base 22 is seen from above. When the sensor base 22 is rotated by the target maintenance angle θm, the X-ray sensors 23a, 23b are at positions of AP1, BP1 when the sensor base 22 is seen from above. As described in FIG. 5, after the rotation of the sensor base 22, the X-ray focal position newly set with respect to the X-ray sensor 23a at the position AP1 is A1, and the X-ray focal position newly set with respect to the X-ray sensor 23b at the position BP1 is B1. Therefore, when the sensor base 22 is rotated, the position of the X-ray sensor 23 changes, and the X-ray focal position with respect to the X-ray sensor 23 also changes. FIG. 9 shows a view showing currently used target maintenance information. The currently used target maintenance information contained in the X-ray target maintenance information 91 will be described with reference to FIG. 9. In the currently used target maintenance information 200, an X-ray focal position 202 indicating the focal position of the X-ray used in imaging at the current time and an accumulated X-ray irradiation time 204 indicating the accumulated time the electron beam is irradiated on the relevant X-ray focal position are corresponded to each other. FIG. 10 shows a view showing previously used target maintenance information. The previously used target maintenance information contained in the X-ray target maintenance information 91 will be described with reference to FIG. 10. In the previously used target maintenance information 210, an X-ray focal position 212 indicating the focal position of the X-ray used in imaging in the past and an accumulated X-ray irradiation time 214 indicating the accumulated time the electron beam is irradiated on the relevant X-ray focal position are corresponded to each other. When the examining target or the examination area is changed, the information on the current X-ray focal position indicated by the currently used target maintenance information is stored in the previously used target information. FIG. 11 shows a view showing NG target maintenance information. The NG target maintenance information will be described with reference to FIG. 11. In the NG target maintenance information 220, an X-ray focal position 222 indicating a position that cannot be used as the X-ray focal position on the target surface, an accumulated X-ray irradiation time indicating the accumulated time the electron beam is irradiated on the relevant X-ray focal position, and an automatic determination flag 226 indicating whether the NG target is automatically decided are corresponded to each other. In the automatic determination flag 226, “ON” is indicated for the X-ray focal position that has been decided that the lifetime is over as the accumulated X-ray irradiation time has exceeded a predetermined threshold value by the maintenance information managing part 86 of the calculation unit 70. “OFF” is indicated for the X-ray focal position that has been decided that the lifetime is over by the user based on perspective image etc. The X-ray examination process described in the next section is then performed using the X-ray examination apparatus 100 having the above configuration. (2. Flow of X-Ray Examination Process) The X-ray examination apparatus 100 according to the present embodiment performs a lifetime determination on the focal position of the target surface when performing the following X-ray examination process. FIG. 12 shows a flowchart showing an outline of the X-ray examination process of the X-ray examination apparatus 100. The outline of the X-ray examination process will be described with reference to FIG. 12. The details of steps S100, 102, 104, and 112 will be hereinafter described. This flowchart is merely an example of the X-ray examination process, and may be executed with the steps interchanged. First, in step S100, the examination area is set with respect to the examining target, and the X-ray focal position information is calculated. The examination area may be arbitrarily set by the user through the input unit 40, or may be set referencing the information on the examination area set in advance. A plurality of examination areas may be set. The calculation unit 70 calculates the X-ray focal position information. In step S102, imaging is carried out based on the X-ray focal position information. Here, the process may proceed to the process of step S104 after all the imaging process is completed with respect to each X-ray sensor 23, or steps S102 and S104 may be performed in parallel in which case the imaged image data is sequentially provided for the process of step S104. Subsequently, in step S104, back projection is performed based on the plurality of image data to a three-dimensional reconstruction space to generate reconstruction data and obtain a CT image according to the CT algorithm. In step S106, examination is carried out based on the reconstruction data. The examination includes a case where the user performs the examination with the reconstruction data displayed on a display etc., and a case where decision is automatically made based on the reconstruction data. Lastly, in step S108, the calculation unit 70 determines whether or not imaging of all the examination areas set in step S100 is terminated. If determined that the imaging of all the examination areas is not terminated (NO in step S108), the examination area to be imaged is changed to the next set examination area in step S110, and the process returns to the process of step S102. If determined that the imaging of all the examination areas is terminated (YES in step S108), the calculation unit 70 makes a judgment on the lifetime of the target of the X-ray focal position currently used in imaging in step S112, and terminates the process. The timing for making the judgment on the lifetime of the target may be any timing as long as the X-ray examination apparatus is being used, and does not necessarily need to be performed after step S108. FIG. 13 shows a flowchart describing the process in step S100 of FIG. 12. The details of the process in step S100 of FIG. 12 will be described with reference to FIG. 13. In step S120, the input unit 40 accepts the setting of the examination area by the user. The location (e.g., position coordinate) of the examination area is then provided to the X-ray focal position calculating part 82. In step S122, the input unit 40 accepts the setting of number of imaging by the user. The number of imaging is then provided to the X-ray focal position calculating part 82. The number of imaging may be automatically set by the imaging condition setting part 84 according to the examining target and the examining item, or may be arbitrarily set by the user. In the present embodiment, the number of imaging is an integral multiples of the number of X-ray sensors attached to the circumference of the sensor base. Subsequently, in step S124, the X-ray focal position calculating part 82 determines whether or not the set number of imaging is greater than the number of X-ray sensors attached to the circumference of the sensor base. If determined that the number of imaging is greater than the number of X-ray sensor (YES in step S124), the X-ray focal position calculating part 82 calculates the sensor base reference angle at rotating the sensor base in step S126. If there are n X-ray sensors 23, and the number of imaging is n×m (m is an integer greater than or equal to 2), m sensor base reference angles are calculated. Specifically, the sensor base angle is 0 degree, 360/n/m degrees, . . . , (360/n/m)×x degrees (x=1, . . . , m−1). For instance an example of n=18, m=10 will be described by way of an example. In this case, the number of imaging is 18×10=180. The second sensor base reference angle is 360/18/10=2 degrees, and the last sensor base reference angle is (360/18/10)×9=18 degrees. If determined that the number of image is less than the number of X-ray sensor (NO in step S124), the process proceeds to step S128. In step S128, the X-ray focal position calculating part 82 calculates the information (X-ray focal position, sensor irradiation angle, sensor imaging angle) on each X-ray sensor with respect to the sensor base reference angle. Specifically, the following calculation is performed. The X-ray focal position calculating part 82 calculates the X-ray focal position corresponding to each X-ray sensor. For instance, the intersection of the line connecting the center of the X-ray sensor and the center of the examination area and the target surface is set as the X-ray focal position. The X-ray focal position calculating part 82 calculates the sensor irradiation angle based on the X-ray focal position. The X-ray focal position calculating part 82 calculates the sensor imaging angle β based on the X-ray focal position. The sensor imaging angle β is the angle formed by the line connecting the work 130 and the center of the X-ray sensor 23, and the X-ray sensor 23. The X-ray focal position information is calculated in the above manner. In the present embodiment, the sensor inclination angle α and the sensor arrangement angle γ do not need to be recalculated for every X-ray focal position as they are set in advance. Subsequently, in step S130, the X-ray focal position calculating part 82 determines whether calculation is terminated on all the sensor base reference angles. If determined that the calculation is not terminated on all the sensor base reference angles (NO in step S130), the process returns to the process of step S128. If determined that the calculation is terminated on all the sensor base reference angles (YES in step S130), the X-ray focal position calculating part 82 determines whether or not the X-ray focal position calculated in step S128 overlaps the X-ray focal position stored in the NG target maintenance information in the range of area coefficient D in step S131. If determined as overlapping (YES in step S131), the X-ray focal position calculating part 82 determines whether or not a rotation limit of the reference coordinate axis is exceeded in step S134. For instance, if N X-ray sensors are arranged on the circumference of the sensor base 22, the rotation limit is about 360/N, but the rotation limit is not limited thereto, and may be expressed with other equations or may be set in advance. If determined that the rotation limit is not exceeded (NO in step S134), the rotation angle controller 32 rotates the sensor base by a predetermined angle (sensor base maintenance angle θm) of smaller than or equal to the rotation limit in step S136 to change the position of the X-ray sensor 23, and the process returns to the process of S128. The sensor base maintenance angle θm may be set in advance or may be determined based on the sensor arrangement angle γ. If determined that the rotation limit is exceeded (YES in step S134), the process is terminated. If determined that the calculated X-ray focal position is not overlapping the NG target maintenance information (NO in step S131), the X-ray focal position calculating part 82 stores the calculation result on the focal position in the X-ray focal position information 92 in step S132. That is, with respect to the set examination area, the X-ray focal position, the irradiation angle θ, the sensor inclination angle α, the sensor imaging angle β, and the sensor arrangement angle γ for each X-ray sensor 23 calculated by the X-ray focal position calculating part 82 in step S128 are stored as the X-ray focal position information. The X-ray focal position calculating part 82 performs the process (step S100 of FIG. 12) of calculating the X-ray focal position information in the above manner. FIG. 14 shows a flowchart describing the process in step S102 of FIG. 12. The details of the process in step S102 of FIG. 12 will be described with reference to FIG. 14. First, the scanning X-ray source controller 72 references the X-ray focal position information 92 in step S150. In step S152, the scanning X-ray source controller 72 instructs the scanning X-ray source 10 to perform a control on the electron beam controller 62 to change the irradiating position of the electron beam to the X-ray focal position corresponding to the X-ray sensor. Subsequently, in step S154, the image acquiring controller 74 instructs the image data acquiring part 34 to acquire imaged data from the X-ray sensor that has detected the X-ray transmitted through the examination area. In step S156, the image acquiring controller 74 determines whether or not all the imaged data corresponding to the sensor base reference angle are acquired. If determined that all the imaged data are not acquired (NO in step S156), the process returns to the process of step S152. If determined that all the imaged data are acquired (YES in step S156), the image acquiring controller 76 determines whether or not the imaged data with respect to all the sensor base reference angles are acquired in step S158. If determined that the imaged data is not acquired for all the sensor base reference angles (NO in step S158), the image acquiring controller 74 instructs the rotation angle controller 32 to perform a control to rotate the sensor base 22 so as to agree to the sensor base reference angle which has not yet been rotated to in step S160, and the process proceeds to the process of step S152. If determined that the image data is acquired for all the sensor base reference angles (YES in step S158), the imaging process is terminated. The imaging process (step S102 of FIG. 12) is performed in the above manner. FIG. 15 shows a flowchart describing the process in step S104 of FIG. 12. The details of the process (CT algorithm) in step S104 of FIG. 12 will be described with reference to FIG. 15. In step S170, the 3D image reconstruction part 76 calculates projection data (absorption coefficient image) based on the acquired imaged data. The projection data will be briefly described. Generally, when the X-ray transmits through the examining object, the X-ray amount attenuates as expressed with the exponential function of the following equation (1) by the amount corresponding to the unique X-ray absorption coefficient of each part configuring the examining object.I=I0Exp(−μL) (1)where L indicates a transmission path length, μ indicates an X-ray absorption coefficient, I0 indicates an X-ray air data value, and I indicates X-ray sensor imaged data. The X-ray air data value is imaged data of the X-ray sensor imaged without arranging the examining object, and is generally referred to as a white image. The projection data (μL) calculated with the following equation (2) is obtained according to equation (1).ML=log(I0/I) (2) Various corrections are sometimes performed on the projection data or the X-ray imaged data of before calculating the projection data. For instance, a median filter may be applied to remove noise, or calibration may be performed if characteristics/sensitivity differ for every pixel in the X-ray sensor. In step S172, the 3D image reconstruction part 76 performs reconstruction of image data based on a plurality of projection data calculated in step S170 using the data stored in the X-ray focal position information 92. Various methods such as the Fourier transformation are proposed for the reconstruction method as described in “Digital image processing” (editor: Digital image processing editorial board, published by Computer Graphics Arts Society (CG-ARTS), second edition, published March 2006), pp. 149-154. In the present embodiment, convolution back projection method is used for the reconstruction method. This is a method of back projection by convoluting the filter function such as the Shepp-Logan to the projection data to reduce blurs. Back projection will be briefly described below. FIG. 16 shows a view describing back projection. A case of back projecting voxel data S0 of the reconstruction region 302 will be described by way of example with reference to FIG. 16. In this case, a value of the projection data of a point (pixel of X-ray sensor 304) P0 where the line connecting an X-ray source 300 and the voxel data S0 and an X-ray sensor 304 intersect is set as a value of the voxel data S0. Since the X-ray intensity differs depending on the position (coordinate) of the voxel in this case, intensity correction such as the FDK method may be performed based on the sensor inclination angle, the sensor imaging angle, the irradiation angle, the sensor arrangement angle, and the sensor base reference angle. A pixel P0 can be geometrically calculated from the information stored in the X-ray focal position information 92, and the values of the distance Z1 from the target surface to the examining target and the distance Z2 from the examining target to the center of the X-ray sensor, as shown in FIG. 5 when obtaining the pixel P0. Returning back to FIG. 15, the 3D image reconstruction part 76 lastly determines whether or not the process on all the imaged data is completed in step S174. If determined that the process on all the imaged data is not completed (NO in step S174), the process returns to the process of step S170. If determined that the process on all the imaged data is completed (YES in step S174), the process is terminated. FIG. 17 shows a flowchart for describing the process in step S112 of FIG. 12. The details of the process (lifetime judgment) in step S112 of FIG. 12 will be described with reference to FIG. 17. In step S180, the maintenance information managing part 86 adds the irradiation time of the electron beam to the accumulated X-ray irradiation time corresponded to the X-ray focal position currently used in imaging. In imaging, the exposure time of the X-ray sensor or the X-ray irradiation time is set, and thus the maintenance information managing part 86 calculates the accumulated X-ray irradiation time based on such a setting, and updates the currently used target maintenance information. The accumulated X-ray irradiation time may be calculated based on the time set as above, but the accumulated time may be measured by counting the actual irradiation time. In step S182, the maintenance information managing part 86 determines whether or not the accumulated X-ray irradiation time of the currently used X-ray focal position has exceeded the threshold value indicating the target lifetime. If determined that the threshold value is not exceeded (NO in step S182), the lifetime judgment process is terminated. If determined that the threshold value is exceeded (YES in step S182), the maintenance information managing part 86 instructs the output unit 50 to make a notification that the accumulated X-ray irradiation time exceeds the predetermined threshold value in step S184. The notification is made known to the user by turning ON the alarm, lighting a display lamp, displaying on the display, or the like. Subsequently, in step S186, the maintenance information managing part 86 determines whether or not the maintenance of the target is automatic. Automatic maintenance is a mode of automatically changing the focal position of the X-ray and the sensor base position to enable continuous operation of the X-ray examination apparatus. Manual maintenance is a mode in which the process performed in the automatic maintenance is performed by the user while checking. The X-ray examination cannot be performed in manual maintenance. The user can perform the setting on the automatic maintenance in advance through the input unit 40. If determined that the maintenance is not the automatic maintenance (NO in step S186), the maintenance information managing part 86 terminates the process. In this case, each process of steps S188 to 198 is performed by the user while checking. That is, the user himself/herself does not need to perform each process itself, and merely needs to proceed the process while checking the result of each step executed in the calculation unit 70. If determined that the maintenance is the automatic maintenance (YES in step S186), the X-ray focal position calculating part 86 calculates the X-ray focal position. The details thereof will be hereinafter described. In step S190, the maintenance information managing part 86 determines whether or not the usable X-ray focal position is obtained in step S188. If determined that the usable X-ray focal position is not calculated in step S188 (NO in step S190), the target needs to be replaced, and the maintenance information managing part 86 terminates the lifetime judgment process. If determined that the usable X-ray focal position is calculated (YES in step S190), the X-ray focal position calculating part 86 stores the calculation result in the X-ray focal position information 92 in step S192. The electron beam controller 62 reads the X-ray focal position information 92 and changes the X-ray focal position. In step S194, the maintenance information managing part 86 writes the information on the target used in the previously used target maintenance information, and writes the X-ray focal position information 92 in the currently used target maintenance information, and updates the X-ray target maintenance information 91. Subsequently, in step S196, the rotation angle controller 32 rotates the sensor base 22 so as to become the target maintenance angle calculated in step S188. In imaging, the sensor base after rotation thereafter becomes the reference (reference coordinate axis). Finally, in step S198, the maintenance information managing part 86 turns OFF the alarm and terminates the process. FIG. 18 shows a flowchart describing the process in step S188 of FIG. 17. The details of the process in step S188 of FIG. 17 will be described with reference to FIG. 18. In step S200, first the X-ray focal position calculating part 82 adds a predetermined angle (Δθ) set in advance to the target maintenance angle θm and updates the same. The calculation of the target maintenance angle is merely performed here, and the sensor base 22 is not actually rotated. In step S202, the X-ray focal position calculating part 82 determines whether or not the target maintenance angle has exceeded a limit angle. For instance, if N X-ray sensors are arranged on the circumference of the sensor base 22, the limit angle of the target maintenance angle is about 360/N, but the limit angle is not limited thereto, and may be expressed with other equations or may be set in advance. If determined that the target maintenance angle exceeded the limit angle (YES in step S202), the X-ray focal position calculating part 82 determines that the usable X-ray focal position cannot be calculated in step S216, and terminates the process. If determined that the target maintenance angle has not exceeded the limit angle (NO in step S202), the X-ray focal position calculating part 82 obtains the sensor base reference angle θs in step S204. As described in steps S124, 126 in FIG. 13, determination is made on whether the set number of imaging is greater than the number of X-ray sensors attached to the circumference of the sensor base, and the sensor base reference angle is calculated if determined that the number of imaging is greater than the number of X-ray sensors. The calculation method will be omitted since the description will be redundant. Subsequently, in step S206, the X-ray focal position calculating part 82 obtains an angle in the mechanical coordinate system of each X-ray sensor 23 in a certain sensor base reference angle θs. The sensor base 22 is rotated by the target maintenance angle θm with respect to the mechanical coordinate system indicating the absolute coordinate, and a number of sensor base reference angles θs exist with the rotated place as the reference. Therefore, the sensor base reference angle in the mechanical coordinate system becomes (θm+θs). That is, the position of each X-ray sensor 23 in the mechanical coordinate system becomes (θm+θs+γ) obtained by adding the sensor arrangement angle γ of each X-ray sensor 23 to the (θm+θs). In step S208, the X-ray focal position calculating part 82 obtains the X-ray focal position with respect to each X-ray sensor 23 by geometric arrangement of the imaging system based on the angle of each X-ray sensor 23 in the mechanical coordinate system obtained in step S206. In step S210, the X-ray focal position calculating part 82 determines whether the X-ray focal position with respect to each X-ray sensor 23 is calculated for the last sensor base reference angle. If a plurality of sensor base reference angles θs is calculated in step S204, the X-ray focal position is sequentially calculated for each sensor base reference angle, and determination is made on whether the X-ray focal position is calculated for the last sensor base reference angle. If determined that the last sensor base reference angle is not calculated (NO in step S210), the process after step S206 is performed for the next sensor base reference angle. If determined that the last sensor base reference angle is calculated (YES in step S210), the X-ray focal position calculating part 82 compares the calculated X-ray focal position and the X-ray target maintenance information 91 in step S212. Here, comparison is performed on whether the X-ray focal position indicated by the NG maintenance information contained in the X-ray target maintenance information 91 and the calculated X-ray focal position overlap in the range having the area coefficient D as diameter or diagonal line. In step S214, the X-ray focal position calculating part 82 determines whether overlapping the X-ray focal position of the NG target as a result of comparison in step S212. If determined as overlapping (YES in step S214), the process returns to the process of step S200 to newly recalculate the X-ray focal position. If determined as not overlapping (NO in step S214), the process is terminated. According to the X-ray examination method using the X-ray examination apparatus applied with the X-ray examination device and the X-ray photographing method of the X-ray examination apparatus according to the present invention, the irradiation time at the X-ray focal position of the target surface irradiated with the electron beam is stored. If determined that a predetermined time has elapsed, the position of the X-ray sensor is changed, and the X-ray focal position on the target is moved. The user thus can manage the maintenance of the X-ray examination apparatus with a computer etc. without touching the X-ray source. Therefore, the examination can be continued without requiring time for maintenance. Since the maintenance of the target of the X-ray source can be automatically performed, the X-ray examination apparatus can be easily and conveniently used. Since the irradiation time on one X-ray focal position is reduced by moving the electron beam, the time until the maintenance of the target becomes longer. The frequency of carrying out the maintenance on the target is thereby reduced. The embodiment disclosed herein is merely illustrative in all aspects, and should not be construed as being exclusive. The scope of the invention is defined by the Claims and not by the description given above, and the meaning equivalent to the Claims and all modifications within the scope of the Claims are intended to be encompassed.
	abstract	A nuclear reactor includes a pressure vessel and a nuclear reactor core disposed in the pressure vessel. A subterranean containment structure contains the nuclear reactor. An ultimate heat sink (UHS) pool is disposed at grade level, and an upper portion of the subterranean containment structure defines at least a portion of the bottom of the UHS pool. In some embodiments, the upper portion of the subterranean containment structure comprises an upper dome, which may protrude above the surface of the UHS pool to define an island surrounded by the UHS pool. In some embodiments, a condenser comprising a heat exchanger including hot and cold flow paths is disposed inside the subterranean containment structure; and cooling water lines operatively connect the condenser with the UHS pool.
	claims	1. An analyzer, comprising:a monochromator that receives X-ray radiation emitted by a sample and reflects and refracts the X-ray radiation to create diffraction lines; anda detector that receives the diffraction lines and converts the diffraction lines into an electrical signal;wherein:the monochromator comprises a single-crystal lithium fluoride doped with at least 0.018 mol per kg of a divalent positive ion M present in a fluorinated state; andthe analyzer is configured to perform elemental analysis of the sample. 2. The analyzer as claimed in claim 1, wherein the ionic radius of the divalent ion M ranges from 55 to 80 picometers. 3. The analyzer as claimed in claim 2, wherein M is present in the fluoride in an amount of at least 0.02 mol per kg. 4. The analyzer as claimed in claim 3, wherein M is present in the fluoride in an amount of at least 0.023 mol per kg. 5. The analyzer as claimed in claim 4, wherein M is present in the fluoride in an amount of at least 0.025 mol per kg. 6. The analyzer as claimed in claim 1, wherein M is present in the fluoride in an amount of at most 0.082 mol per kg. 7. The analyzer as claimed in claim 6, wherein M is present in the fluoride in an amount of at most 0.045 mol per kg. 8. The analyzer as claimed in claim 1, wherein M is Mg2+. 9. The analyzer as claimed in claim 1, wherein M is Co2+. 10. The analyzer as claimed in claim 1, wherein M is Zn2+. 11. The analyzer as claimed in claim 1, wherein M is a mixture of at least two ions chosen from Mg2+, Zn2+ and Co2+. 12. The analyzer as claimed in claim 1, wherein the fluoride is present in the form of a cube or a parallelepiped shape. 13. The analyzer as claimed in claim 1, wherein the volume of the fluoride ranges from 2.5×10−3 cm3 to 30 cm3. 14. The analyzer as claimed in claim 13, wherein the volume of the fluoride ranges from 0.01 to 20 cm3. 15. The analyzer as claimed in claim 1, wherein the fluoride has a cleaved surface. 16. The analyzer as claimed in claim 1, wherein the fluoride has a surface that is ground and then treated in an acid medium or polished. 17. The analyzer as claimed in claim 1, wherein the detector comprises at least one scintillator consisting of a rare-earth halide. 18. The analyzer as claimed in claim 17, wherein the rare-earth halide is CeCl3-doped LaCl3 or CeBr3-doped LaBr3. 19. A method, comprising:analyzing an element of a specimen with the analyzer as claimed in claim 1;wherein:the analyzer comprises a detector consisting of a scintillator; andthe scintillator is set on a line having a wavelength of less than 3 Å. 20. The method as claimed in claim 19, wherein the scintillator is set on a line having a wavelength of less than 2 Å. 21. The method as claimed in claim 20, wherein the scintillator is set on a line having a wavelength of less than 1.5 Å. 22. A process for performing elemental analysis of a sample, comprising:exciting the sample with a primary X-ray beam so that the sample emits a second X-ray beam by fluorescence;reflecting and refracting the second X-ray beam into diffraction lines with a monochromator; anddetecting the diffraction lines and converting the diffraction lines into an electrical signal with a detector;wherein the monochromator comprises a single-crystal lithium fluoride doped with at least 0.018 mol per kg of a divalent positive ion M present in a fluorinated state. 23. A single-crystal lithium fluoride doped with 0.023 to 0.082 mol per kg of a divalent positive ion M present in the fluorinated state, wherein essentially all M ions are in the single-crystal cation lattice. 24. The fluoride as claimed in claim 23, wherein the ionic radius of the divalent ion M ranges from 55 to 80 picometers. 25. The fluoride as claimed in claim 24, wherein M is present in an amount of at least 0.025 mol per kg. 26. The fluoride as claimed in claim 25, wherein M is present in an amount of at most 0.045 mol per kg. 27. The fluoride as claimed in claim 23, wherein M is Mg2+. 28. The fluoride as claimed in claim 23, wherein M is Co2+. 29. The fluoride as claimed in claim 23, wherein M is Zn2+. 30. The fluoride as claimed in claim 23, wherein M is a mixture of at least two ions chosen from Mg2+, Zn2+ and Co2+. 31. The fluoride as claimed in claim 23, wherein said fluoride is present in the form of a cube or a parallelepiped shape. 32. The fluoride as claimed in claim 23, wherein the volume of said fluoride ranges from 2.5×10−3 cm to 30 cm3. 33. The fluoride as claimed in claim 32, wherein the volume ranges from 0.01 to 20 cm3. 34. The fluoride as claimed in claim 23, wherein said fluoride has a cleaved surface. 35. The fluoride as claimed in claim 23, wherein said fluoride has a surface that is ground and then treated in an acid medium or polished. 36. A method for preparing a monochromator, comprising utilizing the fluoride of claim 23.
	abstract	A drawing apparatus includes an aperture array, a lens array configured to form a plurality of crossovers of a plurality of charged particle beams from the aperture array, and a projection system including an element having a single aperture and configured to converge the plurality of charged particle beams corresponding to the plurality of crossovers and to project the plurality of charged particle beams having passed through the single aperture onto the substrate. The lens array includes a correction lens array including a converging lens eccentric relative to corresponding one of a plurality of apertures of the aperture array such that the plurality of charged particle beams converged according to aberration of the projection system are converged to the single aperture. The lens array includes a magnifying lens array configured, so as to form the plurality of crossovers, to magnify a plurality of crossovers formed by the correction lens array.
043483550	abstract	A fuel assembly for the core of a boiling water nuclear reactor has a plurality of boxes each surrounding a respective bundle of fuel rods. These boxes, are connected at one end to a common bottom unit, intended to be connected to an opening in a supporting plate in the core, and are also connected at their other end to a common top unit. The boxes may be detachably connected to the bottom portion and the top unit and be relocatable within the fuel assembly. Alternatively, the bundles of rods may be arranged for easy withdrawal from the boxes to enable transfer of the rod bundles between the boxes.
039379698	abstract	A gamma ray camera system, such as an Anger-type camera, fitted with a collimator comprising an arrangement of straight and corrugated strips of lead foil. One embodiment comprises a parallel multi-channel collimator employing corrugated strips with regular, parallel corrugations. A second embodiment comprises a focusing multi-channel collimator employing corrugated strips having corrugations which focus substantially to a common point and are generally wider and deeper on the side more remote from said common point.
060524243	description	DETAILED DESCRIPTION OF THE INVENTION The present invention will now be described in detail with particular reference to the case where it is implemented to fabricate a vacuum vessel for a nuclear fusion device. FIG. 1 is a partial perspective view of a double-walled and ribbed vacuum vessel for a fusion device according to an embodiment of the invention. As shown, the vessel is composed of an inner wall 1 and connected via reinforcing ribs 2 to an outer wall 3. Both walls are made of a steel in the shape of a container. The vacuum vessel is to be placed in a tokamak fusion device. As shown in FIG. 2, a tokamak comprises essentially a torus-shaped vacuum vessel 12 which is to contain a plasma 11 and maintain a high vacuum, machinery 13 placed within the vacuum vessel 12 to surround the plasma 11, toroidal field coils 14 wrapped around the minor diameter of the torus, poloidal field coils 15 placed concentric with the vacuum vessel 12, and central solenoid coils 16 placed in a face-to-face relationship with the front of the vacuum vessel 12. The vacuum vessel 12 is also equipped with ports for assisting in maintenance and other operations. The sequence of assembling the vacuum vessel 12 is shown in FIG. 3. First, the inner wall 1 and ribs 2 are set up in T shapes and welded at sites 5 as shown in FIG. 1. Then, a shield 4 is inserted between adjacent ribs to fill the gap. In the last step, the outer wall 3 is placed over the ribs and an electron beam is externally applied at right angles to the outer wall such that the applied beam penetrates the outer wall to reach the abutting rib 2, thereby producing a piercing weld 6. Welding at sites 5 is performed before inserting the shields 4, so it can be effected internally by various welding techniques such as arc welding, electron beam welding and laser beam welding. On the other hand, piercing welding of the outer wall 3 to the ribs 2 is performed at sites 6 after inserting the shields, so external welding methods must be employed. In order to perform arc welding externally, it has been necessary to make holes in the outer wall as indicated by 7 in FIG. 13, through which multi-layer welding is effected. Called "plug welding", this technique requires a huge amount of mechanical work and an extensive welding time; in addition, it is practically impossible to reduce the distortion in welding. Electron beam welding involves fusing of the base metal and can hence penetrate a steel plate about 100 mm thick. The outer wall 3 can be welded to a rib 2 in one step and In the absence of the need to make through-holes as shown in FIG. 13, the amount of mechanical work that must be done is negligible. In addition, the strength of the joint between the outer wall and ribs can be increased by performing continuos welding as shown in FIG. 1. If one wants to obtain the same result by applying arc welding externally, he must first divide the outer wall 3 into short strips 8 as shown in FIG. 13 and then weld the ribs 2 to the strips and connect the strips together by butt or slot welding along lines 18. In this case, too, extensive time is taken to prepare the strips 8; in addition, the plates to be welded have to be clamped in a fixture, vice or jig in order to minimize the distortion in welding. If distortion occurs, the resulting mismatch between the ribs and the strips 8 and between the strips themselves has to be corrected, again taking considerable time. Electron beam welding permits continuous operations by merely moving an electron beam across the width of each strip and even in the fabrication of a large container, each welding site can be welded by one pass, contributing to a marked improvement in the operating efficiency. To make the welded joints of the outer wall and ribs shown in FIG. 1, at least two spaced weld beads are provided. Details of one such joint are shown in FIG. 4. Two weld beads 6 are provided symmetrically with respect to the central axis through the T joint of rib 2 and outer wall 3. FIG. 6 shows the symmetrical bending deformation that occurs predominantly at joints in a vacuum vessel for a fusion device. In FIG. 6, M represents the moment that causes the asymmetrical deformation. The nominal bending stress P.sub.b occurring in the joint shown in FIG. 6 is expressed by: ##EQU1## If an asymmetric bend occurs, bending stresses as shown in FIG. 6 develop in the joint. On the other hand, if two weld beads are provided symmetrically with respect to the center line, the bending stress developing in the right bead is equal in magnitude but opposite in direction to the bending stress in the left bead; as a result, the nominal bending stress occurring in the joint can be cancelled. If a bead width exceeding a weld width that can be obtained by one pass of electron beam welding is required, it should be secured by applying two or more passes of welding. If welding is done according to the scheme shown in FIG. 4, one bead line is fused only once with an electron beam and the desired welding can be accomplished without producing voids in the weldment. In order to reduce the distortion in welding, heat should not get into any areas other than those to be welded. In MIG welding used to perform slot welding, the heat input is about 6,000 kJ/mm whereas only about 1,500 kJ/mm of heat is supplied to produce a joint by performing electron beam welding in accordance with the invention. Thus, the heat input can be reduced to a quarter of the heretofore required value, with the result that the distortion in welding is sufficiently reduced. FIG. 7 shows the strength of primary stress that occurs when a pressure builds up within a vacuum vessel that uses the joint structure produced by electron beam welding according to the invention (see FIG. 4), as compared with the strength of primary stress that develops in a vacuum vessel that uses the joint structure produced by slot welding (see FIG. 5). Primary stress strength measurements were conducted by stress analysis in accordance with a finite element method. The horizontal axis of the graph in FIG. 7 plots Pm/T, where Pm is the strength of primary stress developing in the joint and T is the thickness of a rib plate. The welded joint of the invention was produced using two beads each having a relative width (b/T) of 0.125 whereas the slot welded joint was produced using on bead with a relative width (b/T) of 0.25; however, the weld width relative to the rib thickness T was the same in the two joints. The value of a/T, or the relative length of the unwelded area exterior to each bead root in the joint of the invention, was 0.125 whereas in the slot welded joint, a/T was 0.375. Obviously, the joint structure of the invention can be produced by the same amount of welding and yet the strength of primary stress can be sufficiently reduced to provide higher joint reliability. In order to prevent fracture from occurring at joints, their design stresses need be made comparable to the other parts of the vessel including the outer wall and the ribs. As FIG. 9 shows, if the sum of the widths of weld needs in the joint structure of the invention is at least 25% of the rib thickness, the strength of primary stress that will occur in the joint can be made smaller than the design stress for the outer wall, whereby fracture from the joint can be effectively prevented. The vacuum vessel used in a fusion device is subject to repeated occurrence of a large electromagnetic force due to the plasma disruption and, hence, fatigue strength is another design factor that must be considered. The fatigue strength of the joint can be enhanced by increasing the distance between beads as shown in FIG. 4. Referring again to FIG. 6, bending moments M asymmetric to the rib occur in the joint under the influence of an external electromagnetic force. The resulting stress distribution near the root of a weld bead is shown in FIG. 10 for both the welded joint of the invention and the slot welded joint. For both types of weld, a/T is 0.125 but b/T is 0.125 for the joint of the invention and 0.75 for the slot welded joint, which differs from the joint of the invention in that welding is done not only along the two beads but also in the space therebetween. The vertical axis of the graph in FIG. 10 plots tresca stress and the horizontal axis plots the distance from the bead root. Obviously, the stress distribution in the joint of the invention is in substantial agreement with that in the slot welded joint and the stress concentration in the bead root is independent of the bead width. Therefore, the joint of the invention is in no way different from the slot welded joint in terms of fatigue characteristics and since it can be produced with a smaller amount of welding, the joint of the invention is more favorable for the purpose of reducing the distortion in welding and shortening the overall working time. FIG. 11 shows the stress intensity factor K.sub..theta.max /.delta..sqroot.T as a function of a/T for the case where the joint of the invention is stressed as shown in FIG. 6. The value of K.sub..theta.max /.delta..sqroot.T plotted on the vertical axis of the graph in FIG. 11 is dimensionless and refers to a maximum principal stress intensity factor, in which .sigma. represents the bending stress. As one can see from FIG. 11, the smaller the distance between the welding point (a/T) and the surface of the rib, the smaller the value of K.sub..theta.max /.delta..sqroot.T and, hence, better fatigue characteristics are assured. If a/T exceeds 0.2, K.sub..theta.max /.delta..sqroot.T is substantially constant; therefore, better fatigue characteristics are achieved by adjusting a/T to 0.2 and below. FIG. 12 shows the interior of a double-wall structure for a vacuum vessel according to another embodiment of the invention. In this alternative case, wraparound welding is performed as indicated by 10 at both the start and end points of each joint produced by applying continuous electron beam welding along the rib. Since the ribs are subject to a strong force in the poloidal direction, the start and end points of electron beam welding which will be discontinuous areas are preferably reinforced by performing wraparound welding at the corresponding sites 10. Wraparound welding can be effected even after the shields are inserted and it contributes to a further improvement in the reliability of the joint of the invention. According to the welding method of the invention, the distortion in welding can be sufficiently reduced to enable precise and efficient assembling of a double-wall structure that can reasonably withstand the large electromagnetic force caused by plasma disruption.
	abstract	A nuclear fuel rod for a fast reactor is provided, in which a reactor core of the fast reactor can be designed compact-sized by reducing the length of the nuclear fuel rod to be smaller than the length of a conventional one. The nuclear fuel rod for a fast reactor includes a tubular fuel materials comprising a hollow portion formed therein, a tubular inner pipe inserted into the hollow portion of the tubular fuel materials to prevent collapse of the tubular fuel materials due to combustion of nuclear fuel, a tubular cladding pipe which surrounds the tubular fuel materials, and a liquid metal, or He gas or vacuum applied in a gap between the tubular fuel materials and the tubular cladding pipe, and the tubular inner pipe includes a collecting space formed therein to collect fission products such as fission gas which are generated due to combustion of the nuclear fuel.
	abstract	Within an upper plenum of a nuclear reactor, a portion of a heated coolant flows radially outward from a central portion of a core barrel (30) towards outlet nozzles (12) in a region of an upper core plate (21) extending outside of an outer periphery of the core along an inner wall of a core barrel (30). Portions of the coolant flows beneath the outlet nozzles (12). Thus, streams of heated coolant flowing in opposite directions may collide with each other. After collision, the flow directions of the heated coolant are changed to flow upward. Due to the collision, the coolant flow behavior becomes complicated and unstable, making it difficult to measure the temperature of the heated coolant with an outlet pipe (42) connected to the outlet nozzle (12). Within an upper plenum (40) defined above a fuel region through which a coolant flows and which is hydraulically communicated with a plurality of outlet nozzles (12) mounted on a side wall of a nuclear reactor vessel (10), short flow stabilizing members (1) each being lower than the outlet nozzle (12) are disposed in the vicinity of a core barrel (30) in an region outside of the fuel region.
	description	The invention relates generally to computerized modeling of integrated circuits and, in particular, to methods for distributing process variables by spatial interpolation for use in a circuit simulation tool. Electronic design automation (EDA) tools, such as circuit simulation tools, are routinely used to model integrated circuits. Effective circuit simulation tools permit a circuit designer to simulate the behavior of a complex design, identify any problems, and make alterations and enhancements to the integrated circuit before arriving at a final design. Circuit simulation tools formulate and solve the nonlinear algebraic differential equations associated with an integrated circuit design, as is known in the art. Accurate simulation modeling of on-chip process variables, such as film thicknesses, is essential to accurately model high-performance circuit behavior, such as timing, power consumption, functionality, and design yield. Various different conventional statistical spatial correlation methods for process variables are available for use in circuit simulation tools. In bounding box methods, a box is drawn around the objects that may be correlated and, based upon some metric of the box (e.g., a diagonal), a nominal level of spatial correlation is assumed. Unfortunately, bounding box methods represent an experience-based, heuristic approach. In exact methods, a principal component analysis (PCA) is executed to exactly identify the spatial correlation for each set of objects for which spatial correlation information is desired. Unfortunately, exact methods are a relatively expensive approach that is rarely implemented in practical tools. Rectangular grid methods, which represent the prevalent approach for statistical spatial correlation, employ a fixed rectangular grid smaller than the spatial correlation distance. A single PCA is performed and applied to all sets of objects being considered, as a function of which grid cell they occupy. The rectangular grid approach assumes that the spatial correlation is constant within each grid, which allows the spatial correlation to be considered by defining the contents of each grid element to be a linear combination of the raw statistical data in the surrounding grids. Although conceptually similar to the rectangular grid approach, the hexagonal grid approach may be more computationally accurate given the higher packing density and lowered directional dependence of hexagonal grid cells in comparison with rectangular grid cells. None of these conventional approaches is capable of continuously distributing the process variables across a chip, which denotes a significant deficiency. In rectangular and hexagonal grid approaches, discontinuities occur across grid boundaries. Devices bounded within each of the individual grid regions behave identically. However, devices bounded in adjacent grid regions behave differently regardless of the spacing between these devices, which leads to a mismatch in behavior. Generally, conventional approaches fail to maintain the local spatial correlation and, more often than not, are computationally inefficient. Consequently, improved methods are needed for distributing process variables for use in circuit simulation tools that overcome these and other deficiencies of conventional approaches of distributing process variables. In one embodiment, a method is provided for distributing a process variable using statistically-correct spatial interpolation. The method includes forming an array of equilateral triangles in a planar coordinate frame, assigning a numerical value of the random variable at each vertex of the array of equilateral triangles, and defining a plurality of test points at respective spatial locations in the planar coordinate frame that are bounded by the array of equilateral triangles. A numerical value of the random variable is distributed at each of the test points by spatial interpolation from one or more of the numerical values of the random variable assigned at each vertex of the array of equilateral triangles. The method further includes adjusting the numerical value of the random variable distributed at each of the test points with a respective correction factor. In accordance with embodiments of the invention, a process variable is randomly sampled from a global distribution and distributed across a chip at equally-spaced test points separated a maximum spatial correlation distance. A statistically-correct interpolation is used to compute the value of the process variable at any position on the chip. The algorithm, which is computationally efficient, can be implemented practically into the languages of conventional circuit simulation tools. Among the benefits of the embodiments of the invention is that process variables are continuously distributed across a chip in a computationally efficient manner. Global statistical distribution and local spatial correlation are maintained by the distribution process and the statistically-correct interpolation. With reference to FIG. 1 and in accordance with an embodiment of the invention, a user defines a global distribution function and a local spatial correlation in block 10 as process inputs for use in distributing a process variable. The user-defined global distribution function contains information relating to various measurements of the process variable made on a chip region 30 (FIG. 2). The global distribution function may be a Gaussian or normal distribution, although the invention is not so limited. For example, a Gaussian distribution with a mean of unity and a standard deviation (i.e., sigma) of 0.2 may be used as the global distribution function for the process variable. The global distribution function may be determined with the assistance of a data analysis software application like MATLAB® commercially available from The MathWorks, Inc. (Natick, Mass.). Correlation is the degree to which two or more quantities are linearly associated. The local spatial correlation supplies the minimum distance, d0, between adjacent spatial locations for which the process variable is spatially correlated. Spatial locations in the global distribution function that are near each other are more likely to have more similar characteristics than those placed far away, which is reflected in the local spatial correlation. For separations between spatial locations exceeding the minimum distance, d0, values of the random process variable are no longer spatially correlated and, instead, are assumed to be statistically independent. In general, the value of the process variable at each spatial location is distributed within a range bounded between a minimum value and a maximum value. The process variable may be, for example, a height or thickness of the metallization for the M1-level wiring of a multi-level interconnect for the integrated circuit. As a numerical example, an ideal targeted thickness of, for example, 35 nanometers (nm) may be specified in the circuit design for the metallization thickness for the M1-level wiring as a across the entire chip. However, at different spatial locations within the chip region 30, the actual metallization thickness may vary away from the targeted thickness. For example, the actual metallization thickness may range from a minimum value of 32 nm to a maximum value of 40 nm at different spatial locations within the chip region 30. For purposes of description, the term “chip” is considered herein to be synonymous with, and is used interchangeably with, the terms “integrated circuit” and “die”. In block 12, an array of test points 25 are identified in a chip region 30 where a process variable is to be distributed. For example, an array of 400 test points of different spatial locations within the chip region 30 may be specified by the user. The test points 25, which are input by the user, are positioned at regular, equally-spaced locations in a planar (x-y) coordinate frame in which one corner of the chip region 30 is located at the origin of the coordinate frame and the edges of the chip region 30 coincide with the ordinate and abscissa of the planar coordinate frame. In block 14, a plurality of seed points, such as the representative seed points 22, 24, 26, 28, for the process variable to be modeled in the chip design are identified in the chip region 30. As best shown in FIG. 3, adjacent pairs of seed points, including the representative seed points 22, 24, 26, 28, are spatially separated from each other in the x-y plane by a minimum distance, d0, where the local spatial correlation equals zero. An array of bounding equilateral triangles is constructed with edges or sides, such as side 36 of the representative equilateral triangle 34, that connect the seed points, such as the representative equilateral triangles 32, 34 having sides that connect seed points 22, 24, 26, 28. The array of equilateral triangles is a physically correct configuration for the randomly-sampled seed points of the process variable. Because of the arrangement of the seed points, the sides of the equilateral triangles, such as side 36 of representative equilateral triangle 34, have a length equal to the minimum distance, d0, at which the local spatial correlation equals zero. As a result, the grid size for the process variable distribution is equal to minimum distance, d0. Moreover, because of the arrangement of the seed points, a triangle vertex is defined at the spatial location of each seed point in the planar coordinate frame. The equilateral triangles bound the spatial locations of the test points identified in block 12. In block 16, the random process variable is distributed from the global distribution on the seed points in the array of equilateral triangles. The process variable distribution is accomplished by assigning a numerical value of the process variable computed from the global distribution at each of the seed points, which have definite spatial locations in the plane containing the array of bounding equilateral triangles. For example, as shown in FIGS. 4A and 4B, a numerical value of the process variable for each of the representative seed points 22, 24, 26, 28 of the equilateral triangles 32, 34 is picked from the global distribution function. The z-coordinate at each of the seed points 22, 24, 26, 28 is set equal to the numerical value of the process variable derived from the global distribution function. In block 18, a spatial interpolation method is used to interpolate a numerical value of the process variable at the spatial location of the test points 25 identified in block 12. The spatial interpolation method may be implemented using a circuit simulator, such as HSPICE commercially available from Synopsys, Inc. (San Jose, Calif.) or SPECTRE commercially available from Cadence Design Systems, Inc. (San Jose, Calif.). A variety of different interpolation algorithms may be employed to interpolate the numerical value of the process variable at the spatial location of each individual test point 25, as understood by a person having ordinary skill in the art. In block 20, the interpolated numerical value of the process variable at the spatial location of each test point is statistically corrected to account for deviations in the distribution at each test point location from the desired global distribution introduced by the spatial interpolation method. The statistical correction adjusts the interpolated numerical value for the process variable at each test point such that the distribution of all interpolated numerical values conforms more closely with the original global distribution function specified as a process input in block 10. In one embodiment, the statistical correction procedure involves mathematically adding a correction factor in the form of an offset to every interpolated numerical value of the process variable derived from the Monte Carlo simulation. The correction with the offset forces the standard deviation and spatial correlation factor of the interpolated numerical values to more closely match the standard deviation and spatial correlation factor of the user-defined global distribution function constituting one of the process inputs in block 10 (FIG. 1). In the absence of the correction factor, the standard deviation of the calculated values may be significantly smaller than the standard deviation of the global distribution function. The offsets forming the correction factor are continuous across the different equilateral triangles. The global distribution function is preserved on each iteration or run in a Monte Carlo runset, as well as for the accumulated results from different Monte Carlo runsets. The spatial correlation is user-controlled. For purposes of Monte Carlo simulation, the footprint of the representative triangles 32, 34 was divided into three distinct regions and the test points 25 (FIG. 3) were distributed among the three regions according to their spatial location. Certain test points 25 were positioned in planar interpolation regions, which are labeled on FIG. 4A as region “A” inside representative triangle 32 and region “C” inside representative triangle 34. Other test points 25 were positioned in a region “B” located between Regions A and C. Region B represents a curved surface bounded between the two circular arcs 40, 42 in the x-y plane swept about the origins of seed points 26 and 28. Each of the circular arcs 40, 42 has a radius equal to the minimum distance, d0. A representative test point, ta, from among test points 25 is located in Region A within the minimum distance, d0, from each of the seed points 22, 24, 26. Another representative test point, tb, from among test points 25 is located in Region B. Representative test point, tb, is distanced within the minimum distance, d0t from each of the seed points 22, 24, 26, 28. Arcs bordering the edges of the equilateral triangle, such as arc 44, indicate where the distance between neighboring pairs of seed points 22, 24, 26, 28 equals d0. For the representative test point, ta, in Region A, the value of the process variable (z_test) is interpolated onto a plane intersecting the seed points 22, 24, 26. Seed point 22 is assigned coordinates (x2,y2,z2), seed point 24 is assigned coordinates (x3,y3,z3), seed point 26 is assigned coordinates (x4,y4,z4), and representative test point, ta, is assigned coordinates (x_test, y_test). The value of the process variable (z_test) distributed by spatial interpolation at the representative test point, ta, in the planar-interpolation Region A is computed as follows:alpha=(x2−x1)/(x3−x4)gamma=(y1−y2)/(x2−x4)omega=1/(x2−x4)a=(x4−x_test)b=(y4−y_test)beta=(y3−y4)(x2−x4)/(x3−x4)−(y2−y4)AA=aomega−(agamma+b)/beta+(alpha/beta)(agamma+b)+1BB=(agamma+b)/beta−aomegaCC=−(alpha/beta)(agamma+b)z_test=AAz4+BBz2+CCz3 A numerical value for the process variable at additional test points of the array in Region A, as well as those test points of the array in Region C, are spatially interpolated in a similar manner to the procedure for spatially interpolating the value of the process variable for distribution at the representative test point, ta. For the representative test point, tb, in Region B, the value of the process variable (z_test) is distributed by spatial interpolation onto the curved surface between the arcs. Representative seed point 28 is assigned coordinates (x1,y1,z1) and the representative test point, tb, is assigned the spatial coordinates (x_test, y_test). The value of the process variable at test point, tb, within Region B is specified as a mathematical combination of the values of the process variable calculated for the planar-interpolation regions (Regions A and C). Within the planar interpolation region of seed points 22, 24, 28 (Region C), the following equations are solved:alpha=(x2−x3)/(x1−x3)gamma=(y3−y2)/(x2−x3)omega=1/(x2−x3)a=(x3−x_test)b=(y3−y_test)beta=(y1−y3)(x2−x3)/(x1−x3)−(y2−y3)AA—a=aomega−(agamma+b)/beta+(alpha/beta)(agamma+b)+1BB—a=(agamma+b)/beta−aomegaCC—a=−(alpha/beta)(agamma+b) Within the planar interpolation of seed points 22, 24, 26 (Region A), the following equations are solved:alpha=(x2−x3)/(x4−x3)gamma=(y3−y2)/(x2−x3)omega=1/(x2−x1)a=(x3−x_test)b=(y3−y_test)beta=(y4−y3)(x2−x3)/(x4−x3)−(y2−y3)AA—b=aomega−(agamma+b)/beta+(alpha/beta)(agamma+b)+1BB—b=(agamma+b)/beta−aomegaCC—b=−(alpha/beta)(agamma+b) The results from the planar interpolation in Region A and the planar interpolation in Region C are smoothly joined across Region B to determine a value of the process variable for test point, tb, by a mathematical combination given by:z_test=(kaAA—a+kbAA—b)z1+(kaBB—a+kbBB—b)z2+kaCC—az3+kbCC—bz4, wherein a ratio of the location of test point, tb, within Region B is given by:ka=(d_middle−l_middle)/d_middlekb=l_middle/d_middle A numerical value for the process variable distributed at additional test points of the array in Region B are spatially interpolated in a similar manner to the procedure for spatially interpolating the value of the process variable for distribution at the representative test point, tb. The statistical offset (stat_offset) added to each calculated value for each of the interpolated test points in the chip region 30, including the representative test points ta and tb, is given by the product of two multiplicative factors. The first multiplicative factor (stat_add) is a random numerical value chosen from original global distribution function with the mean set equal to zero (i.e., value in the original global distribution function minus the mean). The second multiplicative factor (f_c_test) used in the determination of the offset is computed contingent upon the specific interpolation method used to determine the calculated value of the process variable. In an exemplary embodiment, the value of the process variable at each of the seed points 22, 24, 26, 28, which are represented by the z-coordinates (z1, z2, z3, and z4), are assumed to have the same standard deviation and variance. For planar interpolation regions like Regions A and C, the second multiplicative factor (f_c_test) is given by:f—c_test=(1−((AA)2+(BB)2+(CC)2))1/2 The statistical offset (stat_offset) is given by:stat_offset=stat_addf—c_test. In intermediate curved-surface interpolation regions like Region B, the second multiplicative factor (f_c_test) is determined from a position dependent mathematical combination of the second multiplicative factor values in regions A and C given by:f—c_test=(1/(kaka+kbkb)1/2)(1−((kaAA—a+kbAA—b)2+(kaBB—a+kbBB—b)2+(kaCC—a)2+(kbCC—b)2))1/2 The statistical offset (stat_offset) for test point, tb, is given by:stat_offset=(stat_add—aka+stat_add—bkb)*f—c_test A numerical value of the process variable was interpolated for a plurality of test points within the chip region 30 using a local spatial correlation and a Gaussian global distribution function as process inputs. The mean of the Gaussian global distribution function was set at 1.0059 and the standard deviation was chosen to be 0.19735. The minimum distance, d0, where the local spatial correlation approaches zero, was chosen to be 90 microns (μm). After 1000 Monte Carlo iterations, the interpolated values of the process variable at the test points exhibited a mean of 1.0094 and a standard deviation of 0.14457. After executing a statistical correction as outlined above, the statistically-correct interpolated values of the process variable at the test points exhibited a mean of 1.0087 and a standard deviation of 0.19773. The conclusion is that the statistical correction procedure causes the mean and standard deviation of the interpolated values of the process variable to more closely approximate the mean and standard deviation of the global distribution function. In FIG. 5, the local spatial correlation for the statistically-correct interpolated values of the process variable is plotted as a function of separation distance between test points in the x-y plane (FIGS. 2, 3, 4A, 4B) for the 1000 Monte Carlo iterations. An envelope 50 is defined that bounds the scatter plot of the correlation coefficient from the different Monte Carlo iterations. Line 52 represents the global distribution function input into the interpolation process, which approaches zero at the minimum distance for the local spatial correlation. As apparent from the symmetry of the envelope 50 about line 52, the local spatial correlation of the process variable resulting from the statistically-correct interpolation approximates the local spatial correlation of the global distribution function used as a process input. In alternative embodiments of the invention, the local spatial correlation does not have to extend from unity to zero, as shown in FIG. 5. For example, the local spatial correlation may begin at a numerical value less than unity to represent truly random variations. As another example, the local spatial correlation can end above zero to represent global process variations. The statistically-correct interpolation techniques are described herein in the context of the design of on-chip circuitry and variations of process parameters or variables inside a single die (i.e., intra-die variations). However, the statistically-correct interpolation techniques may find wider applicability in any technological field that requires correct spatial correlation of a random parameter or variable. While the invention has been illustrated by a description of various embodiments and while these embodiments have been described in considerable detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Thus, the invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method, and illustrative example shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicants' general inventive concept.
	summary
052689425	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to cooling systems used to cool water in the nuclear reactor of nuclear power generating facilities and, more particularly, to temporary cooling systems which supplement existing cooling systems in such facilities. 2. Prior Art In nuclear power generating facilities, nuclear fuel and water are contained in a reactor vessel positioned in what is commonly called a refueling cavity or a reactor cavity. During power generation, a primary fluid, normally water, is heated by the nuclear fuel, providing steam for electric power generation. During shutdowns for refueling and other periods when the reactor is not operating, decay heat from the fuel continues to heat the water in the reactor vessel. The water must be cooled to a desired level before fuel may be removed from the vessel and transferred to the spent fuel pool (SFP) of the facility via the reactor cavity. The reactor core is cooled of residual decay heat during shutdown by a permanently installed residual heat removal (RHR) system. It provides heat exchange cooling for decay heat coming from the fuel in the reactor core during shutdown. The heat removal capacity of this system is necessarily large. During normal shutdown, the RHR system is operated for a number of days in order to remove decay heat from the fuel to a point where it may be removed from the core. This is due to the fact that the SFP, the eventual storage place for the fuel, has a permanently installed cooling system, the SFP Cooling System, which does not have sufficient cooling capacity to remove the high level of residual heat immediately following plant shutdown. Thus, in situations requiring removal of the fuel from the reactor core, the permanent cooling system configuration in present-day nuclear plants requires that the RHR system be operated for a period of days in order to cool the fuel such that it may then be removed to the SFP, then allowing reactor servicing, such as fuel replacement or the decontamination of components such as the reactor recirc system (RRS). The current practice prior to the instant invention was simply to wait until cooling by the RHR system was complete and then proceed to remove the fuel. This increased the facility shutdown period by the number of days required for such cooling, thus increasing the cost of the shutdown operation, lost revenues, as well as the cost of replacement power purchased during the shutdown. The cost of replacement power alone is currently measured in hundreds of thousands of dollars per day. However, permanently increasing the capacity of the SFP cooling system is inordinately expensive and impractical. It is therefore the accepted practice to continue with lengthy prior art cooling methods using the existing systems. SUMMARY OF THE INVENTION Considering the prior art problems discussed above, it is an object of this invention to provide a temporary cooling system and method for removing decay heat from a nuclear reactor which allow a temporary connection to be made to either the spent fuel pool or the reactor cavity of a nuclear reactor for supplemental cooling of the primary fluid within the SFP and/or the reactor, accomplished with temporarily placed cooling equipment. It is another object of this invention to provide a temporary cooling system and method for removing decay heat from a nuclear reactor wherein the primary fluid is both cooled and filtered for particulate matter. It is yet another object of this invention to provide a temporary cooling system and method for removing decay heat from a nuclear reactor wherein the primary fluid is both cooled and demineralized. Accordingly, in combination with a nuclear power generating facility including a composite fuel pool including a reactor cavity and a spent fuel pool fluidly connectable to the reactor cavity, the composite fuel pool at least partially containing a primary fluid, a nuclear reactor vessel positioned in the reactor cavity, a residual heat removal system installed in the facility and fluidly connectable to the reactor vessel, and a spent fuel pool cooling system installed in the facility and fluidly connectable to the spent fuel pool, a temporary cooling system is provided, comprising a primary heat exchange system including a primary heat exchanger for transferring heat from a primary fluid to a secondary cooling fluid. The primary heat exchanger is temporarily locatable in the facility, and is temporarily fluidly connected to the composite fuel pool. A primary pump, also temporarily locatable in the facility, circulates primary fluid through the primary heat exchanger, which cools the primary fluid to a desired point at a faster rate than the spent fuel pool cooling system, allowing fuel to be immediately removed from the reactor rather than waiting for the residual heat removal system to cool the primary fluid to a point at which the spent fuel pool cooling system is able to provide adequate cooling capacity. Particulate filtration and demineralization may also be furnished with the system and method of the invention.
062787667	description	DESCRIPTION OF THE INVENTION The following embodiments illustrate and exemplify the present invention and concept thereof. Yet in that regard they are deemed to afford the best embodiments for the purpose of disclosure and to provide a basis for the claims herein which define the scope of the present invention. Referring to FIG. 1, a patient's body B lies on a treatment machine couch 1 which is typical for a LINAC. The patient's head H is secured by a stereotactic ring 2 and head posts 3 to the patient's cranium. The ring 2 is immobilized to the LINAC couch by attachments 4. A target volume 5 is shown within the patient's head. A LINAC machine 7 is shown schematically by the dotted outline. Within the gantry of the LINAC are usually a set of blocking jaws which are typical opposing sets of orthogonal jaws, indicated by the pair 8 and 9 which move in the directions indicated by the arrow 10, and jaws 11 and 12, indicated by the arrows 13. A source of X-rays S delivers an X-ray beam with nominal direction indicated by the dashed line 15 converging on the target volume 5. The X-ray beam is defined by the outline of the circular collimator aperture 16 and the position of the jaws 8, 9, 11, and 12 as they intercept the beam profile through the aperture 16. The invention relates to the use, in combination, of circular apertures or other shaped fixed apertures together with blocking jaws in a linear accelerator to provide hybrid shapes of beams which enable better conformal dosimetry towards the target volume. FIG. 2 gives an example of a so-called "beam's-eye view" of a circular collimator used in conjunction with straight edged jaws in accordance with the present invention. The circular collimator profile is indicated by the dashed outline 18, and the straight edged jaws are illustrated by the dashed area 8 and 9. This view is as seen by the beam looking down the direction of the circular collimator. The nominal beam axis 15 of FIG. 1 is indicated through the point 19 in FIG. 2. The open area between the jaws 8 and 9 and the circular collimator is indicated by the solid line perimeter 20. For an irregularly shaped target volume, indicated by the profile 21, the solid line 20 conforms very much more closely to the target volume than if only the circular collimator 18 were used or, alternatively, if only the jaw configurations 8 and 9 were used. Thus the combination of the circular collimator and straight edged jaws gives much more conformality to a target volume from a given beam direction than the jaws separately or the circular collimators separately. Referring again to FIG. 1, such a configuration of beam's-eye view profile would then be swept through arcs indicated by the arrows 21 according to the so-called gantry angle and couch angle of a linear accelerator (see the specifications, for example, from Varian Corporation, California, or Siemens Corporation, California, for LINACs). Referring to FIG. 3 is another embodiment example of the present invention where (with similar numbering as given above) jaws 8 and 9 provide a straight edge perimeter and jaw 12 is one of an orthogonal pair which together with the circular collimator aperture gives rise to a solid line contour 22 that conforms relatively tightly to the tumor profile 23. Here the use of three jaws is invoked to eclipse the circular aperture 18 to provide better conformality. Other examples may be given of irregularly shaped tumors and one, two, three, or four jaws of the typical four pairs in a LINAC, as illustrated in FIG. 1, can be used to bring in secant type eclipses to the circular collimator shape to provide the best conformality with this combination of apertures. Different size radius collimators 18 could be invoked, depending on the size of the tumor. In accordance with the present invention and illustrated by FIG. 4, a system and process comprising determination of jaw positions 25 and selection of circular collimators 26 is used in cooperation with a conformal treatment planning system 27 such as the XKnife software and computer workstation of Radionics, Inc., Burlington, Mass. Such a computer workstation will have input data from image scanning of the patient's body 28 from a CT or MRI scanner, and treatment planning of beams and dosimetry can be handled in computer system 27. From this, a selection of jaw configurations in combination with circular aperture sizes can be derived, thus determining the values of jaw position 25 and circular collimator size 26. Once determined for a given arc, the jaws and circles may be fixed and the delivery of an arc with this configuration, such as illustrated by arc 30 in FIG. 1, can give rise to conformal radiation to target volume 5. The jaws may also move as the beam arc is swept over the patient in a more dynamic mode. Thus, a process of treatment planning with jaw and circular arc beams is illustrated. CT image data 28 together with treatment planning system is in accordance with the target volume and appropriate beam positions. Thereby, a selection of jaw positions and circular collimator sizes can be determined together with associated arc therapy. The treatment planning system 27 can also derive the arc positions and the arc lengths as well as X-ray dose to optimize the dosimetry on a target such as 5 in FIG. 1. Dose algorithms can be derived (such as those from XKnife or XPlan of Radionics, Inc., Burlington, Mass.) that can derive dosimetry from such jaw/circular collimator ports with swept LINAC arcs. The results of such dosimetry indicate, according to the present invention, that the quality of the conformality of the dose to the target volume is superior and the degree of radiation to normal tissue outside of the target volume is reduced from the situation where only circular collimators are used or only standard jaw configurations are used independently. Thus the present invention represents an improvement over the dosimetry possible by each of these previously used, independent methods. Since square jaws are existent in most standard linear accelerators, and circular collimators are used in standard radiosurgery, the combination of these two elements when used according to the present invention can give substantially superior radiation dose to a target volume. Once a treatment plan has been derived, the appropriate dose plan, collimator sizes, LINAC settings, and arc configurations can be derived (element 32), and the treatment of the patient can proceed (element 33). Variations of the present invention may be apparent to those skilled in the art, and the system may take other forms with a multitude of variations. The use of noncircular collimators (aperture 16) can be invoked, and this can be used as cut blocks. The use of non-orthogonal jaws in a LINAC may also be used. A non-conventional set of jaws involving one or more jaw configurations may be used in conjugation with a circular aperture in accordance with the present invention to improve treatment planning. For instance, a special set of extra jaws could be built into the LINAC in conjugation with a circular collimator as a dedicated jaw-circle collimator apparatus. Various dose algorithms may be used to determine the dosimetry for jaws and circular collimators. In view of these considerations, and as will be appreciated by persons skilled in the art, implementations, systems, and processes could be considered broadly and with reference to the claims as set for below.
	description	This application claims the benefit of U.S. Provisional Application No. 61/114,113, “Mixed Bismith Compounds for Iodine Capture”, filed Nov. 13, 2008; which is incorporated by reference herein. The United States Government has rights in this invention pursuant to Department of Energy Contract No. DE-AC04-94AL85000 with Sandia Corporation. The invention relates generally to methods and materials for disposal of radioactive iodine wastes from nuclear reactor fuel cycles, as well as capture and immobilization of non-radioactive iodine species. Radioactive 129I is one of the longer-lived fission products (1.6×107 years) resulting from the generation of nuclear energy, and it is also one that is associated with considerable public concern by virtue of the obvious mechanism whereby it may become concentrated in the human body. Historically, 129I was simply discharged to the atmosphere. Currently, iodine is discharged to the ocean (principally the seas around Europe) for isotope dilution with the natural iodine in seawater. With the growth of research on advanced fuel cycles in the United States and abroad, there is a strong interest in the separations and waste form development for all radioisotopes that are isolated in the developing nuclear cycles. This includes the initial trapping of gaseous iodine radioisotopes, and their incorporation into waste forms. Whether wastes are slated for above ground storage, or underground burial, a serious need is that the radionuclides (129I, in our case) exist in chemical forms that will not be readily dissolved should water gain access to the site. A second major consideration is that the wastes not exist as powders, since an accident during storage or handling could produce a cloud of radioactive dust with the potential for causing widespread contamination. A number of research groups have investigated the complex crystal structures of layered bismuth oxy-iodide compounds. In particular, the researchers focused on the subtle, yet related, differences in the topography of the bismuth oxide layers, and the stacking around the iodine complexes located between the layers (see FIG. 1). Due to the high measured stability limits of bismuth carbonates and iodides with respect to saline groundwater, recent research in Canada has focused on the use of individual bismuth oxyiodide compounds as candidates for radioactive iodine waste forms. Hence, a need exists for improved methods of synthesizing mixed-layer bismuth oxyiodine and oxy-iodate materials for use in the in-situ recovery of radioactive iodine from caustic waste streams and/or final waste form. In particular, we are focused on the use of these mixed-layer Bi—O—I waste forms if repository conditions are at temperatures at, or below, those under which the iodine was initially captured. The invention relates to materials and methods of synthesis of mixed-layered bismuth oxy-iodine materials, in an effort to develop materials for iodine recovery from caustic waste streams (e.g., NaOH or KOH) and/or for final waste disposal; in particular, if repository conditions included ambient temperatures similar to those under which the iodine was initially captured. The results presented involve the in-situ crystallization of layered bismuth oxide compounds with aqueous dissolved iodine (which resides as both iodide (I−) and iodate (IO3−) forms in solution). Although individual bismuth oxy-iodide compounds (e.g., BiOI) have already been described in the context of capturing radioiodine, our contribution is the unexpected discovery that there are mixed-layered bismuth oxy-iodine materials that optimize both the uptake of iodine and the degree of insolubility (and un-leachability) of iodine in water. These optimized mixed-layered Bi—O—I materials are suitable as a durable waste form for repository conditions such as are predicted at the Yucca Mountain repository (YMP), or in a similar type of repository that could be developed in coordination with iodine production via DOE/Nuclear Energy-Fuel Cycle R&D Program (FCR&D) and Global Nuclear Energy Program (GNEP, currently focused on US-foreign interactions only) production cycles. This technology provides a one-step process for both iodine sequestration and storage for nuclear fuel cycles or non-nuclear industrial processes. By properly controlling reactant concentrations, optimized compositions of the mixed-layered bismuth oxy-iodine materials can be made that have both a high iodine weight percentage and a low solubility in normal groundwater environments. The general term “bismuth oxy-iodine compounds” is broadly defined herein to include both the iodide (I−) and iodate (IO3−) forms of iodine. The term “mixed-layered Bi—O—I materials” and “mixed-layered bismuth oxy-iodine materials” are interchangeable. Our novel technology generally involves the in-situ crystallization of layered bismuth oxide compounds (See FIG. 1) with aqueous dissolved iodine (which resides as both iodide and iodate in solution). Although individual bismuth oxy-iodide compounds (e.g., BiOI) have already been described in the context of capturing radioiodine, our unique contribution is the unexpected discovery that there are mixed-layered Bi—O—I materials, not described in the prior work, which optimize both the uptake of iodine and the degree of insolubility (and un-leachability) of iodine. When optimized, these mixed-layered Bi—O—I materials are durable materials that are especially suitable as a waste forms for repository conditions, such as are predicted at the Yucca Mountain repository (YMP) or in a similar type of repository that could be developed in coordination with iodine production via advanced nuclear fuel production cycles (or other fuel storage and reprocessing technologies). In this work, we iddntified two (known) layered bismuth oxy-iodide lattice types (lattice phases), i.e., BiOI and Bi5O7I, as primary building blocks in our synthesized mixed-layered Bi—O—I materials. The proportions (relative to each other) of the known lattice phases, BiOI and Bi5O7I, (and possibly additional, unknown Bi—O—I lattice phases) was optimized by to produce a series of intimately mixed layered Bi—O—I materials that have both high iodine uptake in aqueous solutions, and minimal leachability of the iodine component. Leachability concerns in predicted repository conditions include temperatures below 100° C., and in contact with groundwater (aqueous environment) containing competing ions of chloride and carbonate. The meaning of our term “mixed-layered Bi—O—I materials” is different than a simple mechanical mixture (i.e., combination) of individual BiOI or Bi5O7I particles. Instead, the term “mixed-layered Bi—O—I materials” means a “chemical assemblage at an atomistic or molecular scale of at least two different Bi—O—I lattice types or lattice phases.” The “at least two different Bi—O—I lattice types or lattice phases” could be BiOI, or Bi5O7I, or they could be other Bi—O—I lattice phases that haven't yet been identified. The optimized mixed-layered Bi—O—I materials that we made were synthesized under the general mild precipitation method of adding a mixture of Bi(NO3)3+HNO3+KI (or KIO3) into a basic solution (e.g., with NaOH or KOH). The resultant precipitates were aged at elevated temperature (e.g., 70-90° C. for 24 hours, and they ranged in color from yellow to orange depending on composition ranges. The heated solution begins at mild basic pH (approximately >7), and then falls with time to become acidic (pH≈3-4). The solid settles and the solution is decanted off. The solids were repeatedly washed/soaked with DI water until the ionic strength drops and the solids remain in suspension. At this point, the wet slurry was dried at 90° C. for 12 hours, or until completely dry. The methodology we developed for this discovery used a series of varying bismuth-to-iodine ratios in the different mixes that were progressively increased in 10% increments. Ideally, the sample with the greatest content of iodine should have had a Bi:I molar ratio of 1:1, conducive to forming the compound BiOI, if all of the iodine had reacted with the bismuth. In reality, complete uptake of iodine stopped in the mixture of lattice phases in the series at sample #7, and synthesis of pure BiOI was never achieved. Unexpectedly, we discovered that the optimum composition of the mixed-layered Bi—O—I materials fell in the middle of the “1-10” series, (i.e., samples 4, 5, 6), rather than at either end of the spectrum. These three optimized materials incorporated 17-22 wt % iodine into their structures. The relative representations of Bi5O7I and BiOI lattices in the optimized materials were determined by X-Ray Diffraction, XRD, and the elemental compositions were established by X-Ray Fluorescence (XRF). In the optimized materials (samples 4, 5, 6) the relative contributions of the two known bismuth oxyiodide lattice phases were calculated to be: 15-20 mole % Bi5O7I and 85-80 mole % BiOI. Also, the three samples, which had the highest amount of incorporated iodine, also had the lowest solubility of all the materials' combinations when exposed to chloride, sulfate, and carbonate-containing solutions (simulants for possible groundwater contaminants). This last result is quite surprising, because according to Taylor and Lopata, in “Stability of Bismuth Oxyiodides in Aqueous Solutions at 25° C.”, CAN. J. CHEM. Vol. 64, 1986, pp. 290-294, they found: “From the viewpoint of radioactive iodine immobilization, the most important conclusion is that Bi5O7I is seven orders of magnitude more stable than BiOI towards hydrolysis.” However, in our synthesized optimum materials, the highest stability (lowest iodine solubility) was achieved with a very different proportion, i.e., 15-20 mole % Bi5O7I and 85-80 mole % of BiOI (opposite from what Taylor would have predicted from their work). Method of Synthesis All chemicals were used as received without further purification from Fisher Scientific—Certified. In house analytical testing used for characterizing the composition and solubility of the iodine loaded on inorganic bismuth waste forms include: (1) Orion specific ion electrode, (2) PerkinElmer Elan 6100 ICP-MS (3) X-ray fluorescence ARL (Thermo) QUANT'X EDXRF Analyzer, (4) TA Instruments STD Q666 Simultaneous DTA-TGA, (5) Powder X-ray (XRD) Bruker AXS-D8 Advance powder diffractometer. Leaching studies were carried out by a generalized deionized water solubility test (similar to the modified Product Consistency Test Procedure B (PCT test, American Society for Testing and Materials Standards. Standard Test Method for Determining Chemical Durability of Nuclear, Hazardous, and Mixed Waste and Glasses. The Product Consistency Test (PCT), 2008 Annual Book of ASTM Standards. American Society for Testing and Materials Standards, West Conshohocken, Pa., 2008.) method in which powders of the resultant bismuth oxyiodide mixtures were leached in deionized water. A 10 wt % (10 g water/1 g solid) solution of the bismuth powdery material is suspended in DI H2O, and heated at 90° C. for 24 hours in a screw top Teflon container. The resultant liquid was analyzed by ICP-MS (or specific iodine electrode) for leached iodine, and the pH was measured on the cooled solution using a standard pH electrode. Three series of samples (i.e., the “41” series, the “42” series, and the “1-10” series) were prepared by dissolving bismuth nitrate (e.g., as Bi(NO3)3.5H2O) and potassium iodide, mixing them in various ways, and then causing a precipitate to form by occasionally adding a basic solution made with sodium hydroxide (or with any alkali or alkaline earth oxide or hydroxide). Other bismuth salts can be used in place of bismuth nitrate (e.g., bismuth trichloride). Specific details of preparation are given below: Appropriate amounts of solid bismuth nitrate and potassium iodide (KI) salts were added dry to a bottle. Samples 41A and 41B had Bi-to-I ratios appropriate to making Bi5O7I (Bi:I=5); 41C and 41D appropriate to making Bi7O9I3 (Bi:I=2.33); and 41E and 41F appropriate to making Bi4O5I2 (Bi:I=2.00). Then, DI water (˜50 ml) was added and the mixes put on a shaker at room temperature for about an hour. Finally, alternately in every other sample, an aliquot (˜22 ml) of 1 M NaOH (samples 41 B, D, F), or an approximately equal amount of deionized water (samples 41 A, C, E), was added. The mixes were then set back on the shaker overnight. The next afternoon they went into the oven (along with the “42 Series” mixes) to age over the weekend at 90°. C. After three days, the samples were cooled to room temperature, the supernate was decanted off, and the heated solids were rinsed repeatedly with deionized water. At the end of the process the supernates from 41B, 41D and 41F were still strongly basic (blue pH paper), while 41A, 41C and 41E were quite acid (red pH paper). Table 1 summarizes the composition and XRD results. TABLE 1Composition and Characteristicsof Series “41” and “42” Samples:ChemicalAnalysisbybyPrep:25-35by XRFXRFDe-NaOHdeg.I/BiBi/IsignAdded~8.6 A2-ThetamolarmolarBi:IIntensityColor? PeakPeaks41A0.0061595light brownnomajor5, 1 major41B0.2144.685mediumorangeyestrace6, 3 major41C0.011912.33darkorangenomajor4, 1 major41D0.4332.312.33darkorangeyestrace, 3 majorshifted 41E0.0071402light brownnosmall4, 3 major41F0.5201.922darkorangeyestrace,6, 5 majorshifted42A0.0091145mediumbrownnomajor5, 3 major42B0.2134.695light yellowyesnone5, 3 major42C0.015682.33darkbrownnomajor5, 3 major42D0.4052.472.33light orangeyesnone5, 1 major42E0.024422darkbrownnomajor5, 1 major42F0.5211.922light orangeyesnone 2 major Mixes 42 A-F were designed to have the same Bi:I ratios as in the “41 Series”, but the order in which the constituents were mixed was different. First, the appropriate amounts of bismuth nitrate salts were placed in the bottles, and then an aliquot (˜22 ml) of either 1 M NaOH (samples 42 B, D, F) or deionized water (samples 42 A, C, E) was added. Then, 50 ml of deionized water was added to each bottle, and the mixes put on a (room temperature) shaker for 15 minutes. Generally, a white, milky slurry formed as the bismuth nitrate dissolved and hydrolyzed. Finally, the appropriate amounts of KI were added as a solid salt, and the bottles returned to the shaker for about two hours. Samples were then placed in the 90° C. oven over the weekend. The following Monday, the samples were cooled to room temperature, the supernate was decanted off, and the heated solids were rinsed repeatedly with deionized water. At the end of the process the supernates from 42B, 42D and 42F were still strongly basic (blue pH paper), while 42A, 42C and 42E were quite acid (red pH paper). See results in Table 1. The “1-10” series samples were prepared as follows. In this instance, rather than trying to mix Bi and I in specific proportions chosen to mimic known bismuth oxyiodine compounds, the Bi to I ratio was stepped up progressively in small (i.e., 10%) increments. As shown in Recipe #1, these samples were prepared by dissolving bismuth nitrate and potassium iodide in deionized water, and then bringing the pH to near 7 by adding sodium hydroxide (and occasionally back titrating with a little acetic acid when adding the standard aliquot of NaOH resulted in a pH significantly above 7). Samples were then incubated in the 90° C. oven overnight. The bismuth to iodine ratios in the different mixes (samples 1-10) were increased by 10% increments, so that the sample with the greatest content of iodine would have had a Bi:I molar ratio of 1.4 (conducive to forming the compound Bi7O8I5), if all of the iodine had reacted with the bismuth. However, analysis of the post-synthesis fluids indicated, however, that complete uptake of iodine stopped with the 7th sample in the “1-10” series, so that the synthesis of Bi7O8I5 was not actually achieved in samples #8, 9, or 10. The results are shown in Table 2. 1. Label sample bottles #1 through 10; 2. Add 4 g (+/−0.1 g) of Bismuth Nitrate, Bi(NO3)3.5H2O, into each of the ten bottles; 3. Add 50 ml of deionized water to each bottle; 4. Put them on a shaker for 20-40 minutes; 5. Add X grams of potassium iodide (KI) individually to the appropriate bottle, according to the following: Sample No.X grams of KI10.13720.27430.41140.54850.68460.82170.95881.09591.232101.369 6. Shake, record the color produced, then shake for 30 minutes, record color; 7. Add 20 ml of 1 M NaOH to each bottle, shake for 1 hour or overnight, and record color; 8. Place in oven and heat at 90° C. for overnight or over the weekend; 9. Cool the bottles to room temperature, decant the supernate off (save the supernate); and 10. Rinse the remaining precipitated solids repeatedly with deionized water and dry. TABLE 2Composition and Characteristics of the “1-10” Series Sampleswt %wt %molarmolarmoleswt %% I in thepH afterBiII:BiBi:IOIsupernateheating179.404.620.118.791.444.980.41%2.1272.226.450.175.731.417.450.31%2.3377.9914.210.362.811.3214.190.32%2.3474.8017.990.472.131.2617.980.30%4.7569.9021.800.611.641.2022.220.27%5.2657.3717.700.601.661.2022.030.29%6.5767.7228.100.811.231.0927.690.27%6.8861.3324.330.781.291.1126.7712.86%6.9963.7727.380.841.191.0828.4015.55%6.81066.1625.870.761.311.1226.4826.50%6.7 The rational for carrying out the “1-10 Series” synthesis experiments was to approach the matter of synthesis in a more controlled manner. Toward this end, more system variables were assessed; as well as having the Bi:I proportions in the starting mixes incremented in smaller steps. After synthesis, two parameters were measured on the remaining supernate: the pH and the residual iodine left in the solution from which the solids had precipitated (See Table 2). Although the pH of the synthesis fluid was nearly neutral in all samples prior to the final incubation at 90° C., the heating process resulted in further reactions in samples 1-3, which lowered the pH. A post-test iodide analysis of the supernate in samples #1-7 revealed that effectively all of the iodine added in the initial mix was taken up by the solid precipitates. In contrast, for samples 8-10, an analysis of the post-heating supernate suggests that not all of the iodine provided in the synthesis ended up on the solids. This picture was confirmed by the XRF analysis of the solids (FIG. 2), which showed that after sample 7 (i.e., in samples 8, 9, 10) the iodine content of the solids no longer increased, in spite of the fact that additional iodine was provided by the synthesis recipe. The actual weight percent of iodine in the samples, of course, depends on all of the components in the compound (i.e., Bi, O, I, plus any contaminants). In this case the amount of oxygen assumed to be present was computed based on what would be needed to maintain charge balance in a compound containing only oxygen, iodine (as iodide), and bismuth. Earlier FTIR studies on similar compounds had confirmed that neither hydroxide nor carbonate (as a contaminant in the NaOH used in the preparation) were present in significant amounts. Also, the XRF (SEM-EDS) studies confirmed that neither Na nor K (from the base used to precipitate the compounds) was incorporated to a significant degree in the solid precipitates. So, this is a reasonable assumption. X-ray Diffraction (XRD) Studies on Bismuth Oxyiodine Materials Powder X-ray diffraction patterns (XRD) were obtained for all of the materials described above. Many of the patterns exhibit similar features, although in detail there are significant differences, which have entailed some effort to resolve. FIGS. 3 and 4 provide diffraction data on the three “41” and “42” samples (respectively) which exhibited significant uptake of iodine (e.g., B, D, and F). FIG. 5 provides a full display of all ten traces from the “1-10” series materials. These traces ultimately provided the basis for characterizing the materials that were the most stable, and contained the highest proportions of iodine (and hence make the most attractive targets for potential waste form development). Solubility Studies on Bismuth Oxyiodine Materials The solubility of our novel mixed-layered bismuth oxy-iodine materials can be approached from two directions; solubility in pure deionized water using a PCT-type test protocol, and the solubility in normal groundwaters (e.g., with Na+, K+, Ca2+, Mg2+, Cl−, HCO3−, SO42−.). Fortunately, basic thermodynamic data is available for both BiOI and Bi5O7I. Calculations involving these data indicate that both HCO3− and Cl− will quantitatively displace iodide from the waste, even if only present at concentrations of just a few tens of parts per million. Thermodynamic data for the sulfate solubility is not available. Thus, to model the performance of a repository, one can simply equate the outward iodide flux to the incoming flux of chloride plus bicarbonate (and maybe sulfate), provided that the basic solubility of the waste form is significantly less than the indigenous concentrations of the common groundwater anions. In our leaching tests, the level of iodine leached from the various materials is a few parts per million. FIG. 7 clearly demonstrates that there is a significant difference in the overall stability of the different materials, with the materials giving relatively well-defined patterns for BiOI holding a distinct advantage (e.g. lower solubility and, hence, greater stability) over materials at either end of the compositional spectrum. In a general sense, this picture is also supported by the series “41-42” samples (FIG. 6), though, since these experiments did not explore the low-iodine end of the spectrum curves analogous to ASH3-#2 in FIG. 7. Tables 3-5 summarize the solubility test data. (Note: The sample designated “ASH3-#2” is the same as sample 2; “ASH3-#4” is the same as sample 4, “JLK-41B” is the same as sample 41B, etc.) It is noteworthy that these solubility results are quite different from predictions based on thermochemical properties of BiOI3 and Bi5O7I; and that this distinction serves to emphasize the difference between our mixed-layered Bi—O—I materials and the two end-member compositions (BiOI and Bi5O7I); or simple mechanical mixtures thereof. TABLE 3Solubility (ppm iodine) of bismuth oxviodine materials in deionized water.Temp- ASH3-ASH3-ASH3-ASH3-ASH3-° C.#2 #4#6#8#10250.030.010.040.520.91470.070.010.011.031.30750.760.070.012.612.67902.620.210.043.693.62Temp-JLK-JLK-JLK- JLK-JLK- JLK-° C.41B41D41F42B42D42F250.080.060.100.050.140.68470.240.120.410.040.490.43750.220.311.810.020.301.39900.270.552.190.060.421.99 TABLE 4Post-test quench pH values of solubility experiment fluids after sitting for 2-3 weeks at RT.Temp- ASH3-ASH3-ASH3-ASH3-ASH3-° C.#2 #4#6#8#10253.103.463.74.544.45472.983.523.604.544.55753.703.353.614.204.17903.083.153.564.044.05Temp-JLK-JLK-JLK- JLK-JLK- JLK-° C.41B41D41F42B42D42F254.193.814.293.923.723.98473.923.764.183.883.663.82753.733.653.913.683.363.69903.663.64 no spl. left3.713.443.67 TABLE 5Solubility (ppb iodine) of “1-10” series materials in deionized water.Temp° C.#2#4#6#8#102510.204.6911.70178.47333.624723.624.933.71388.52385.3077260.4621.452.61930.37576.8894856.8177.6212.671110.021191.63(PPb)iodine In summary, we unexpectedly discovered a set of closely-related mixed-layered Bi—O—I materials (samples #4-6, Table 2), containing 17-22 weight % iodine, and having X-ray diffraction patterns related to BiOI, (see FIG. 8), which leaches out significantly less iodine than materials synthesized with either more, or less, iodine (relative to the amounts of Bi in the mix). In terms of sample identification, we calculated, for example, that the sample #10 X-ray diffraction pattern could be best matched by assuming a scaled mix of 2 “parts” of the Bi5O7I, XRD pattern and 5 “parts” of the BiOI XRD pattern (See FIG. 9). For the optimized materials (samples 4, 5, 6), the relative contributions to the total XRD pattern from the XRD patterns of the two known bismuth oxyiodide lattice phases was calculated to be: 15-20 mole % Bi5O7I and 85-80 mole % BiOI. FIG. 10 shows the amounts of iodine released (leached) from exposure to deionized water for 3 days at various temperatures. FIG. 11 shows the amounts of iodine released (leached) from exposure to deionized water for 3 days at various temperatures with 0.005 M of common groundwater anions (i.e., sulfate, carbonate, and chloride) added to the water. It can be seen that sample #6 was more stable than sample #8 with respect to iodine leaching. The presence of carbonate ion (HCO3−) produced the greatest amount of iodine leaching. FIG. 12 shows the amounts of iodine released (ppb) for samples 2, 4, 6, 8, and 10 after 3 days exposure to deionized water at 94° C. (see Table 5). One would normally expect there to be a smooth, linear change in solubility as a function of varying composition (wt % iodine), based on a simple rule-of-mixtures behavior, in the samples tested (i.e., there would be a straight line between sample 2 and 10). However, what we unexpectedly found was a strong minimum in the solubility curve at samples 4 and 6 (i.e., at about 18% wt % iodine), where the solubility was reduced a factor of 100× at the minimum, compared to the maximum (for samples 8 and 10). This was a very unexpected result, and supports our belief that our synthesized mixed-layered Bi—O—I materials are not simple mechanical mixtures of the two known, layered end-member compositions (BiOI, and Bi5O7I), but, rather, are a much more complex chemical assemblage, intimately-mixed at an atomistic-scale of two or more layered Bi—O—I lattice phases, possibly more, whose structure is much more stable to dissolution by water than either of the two end-member compositions (BiOI, and Bi5O7I) by themselves. This assessment is further supported by Scanning Electron Microscope (SEM) photomicrographs. FIG. 13 shows a 1000× magnification of sample #1. Long, rectangularly-shaped crystalline blocks can be seen, along with thin plates (flakes) and balls made of flakes (“flakey” balls). FIG. 14 shows a 1000× magnification of sample #6. A few crystalline blocks can be seen, but most of the image shows balls made of thin flakes (“flakey” balls). FIG. 15 shows a 1000× magnification of sample #10. The image shows both balls made of thin flakes (“flakey” balls), and long, thin spikes (needles). Clearly, the microstructure of the three different samples (1, 6 and 10) are vastly different, and are not simple mechanical mixtures of the two known, layered end-member compositions (BiOI, and Bi5O7I). The SEM micrographs in FIGS. 13-15 also show that our synthesized mixed-layered Bi—O—I materials have a very high specific surface area (see, e.g., FIG. 13). It is rather remarkable that, despite the high specific surface area microstructure, any of these materials could have a very low solubility in ground water (e.g., the middle series samples 4, 5, & 6). By using these optimized mixed-layered bismuth oxy-iodine materials, the greatest cost savings can be realized from: (1) the ability to implement this technology into processing wastes from civilian and defense nuclear power cycles and reactors, and by (2) reducing energy consumption plus reduced potential radiological exposure to workers by combined sequestration and waste form materials processing. This process can be applied across the United States and world wide for the removal and storage (for decay) of radioactive iodine compounds. It can be used for both defense and civilian nuclear power cycle productions of iodine gas and iodine aqueous compounds. With respect to the iodine leaching tests shown in FIG. 11, it can be seen that carbonate is apparently the anion of greatest concern in groundwater (i.e., greatest leaching). This raises the interesting possibility of synthesizing even more stable compounds that deliberately incorporate the same carbonate species along with the iodine to make a mixed-layered bismuth-oxygen-carbonate-iodine material. The particular examples discussed above are cited to illustrate particular embodiments of the invention. Other applications and embodiments of the apparatus and method of the present invention will become evident to those skilled in the art. It is to be understood that the invention is not limited in its application to the details of construction, materials used, and the arrangements of components set forth in the following description or illustrated in the drawings. The scope of the invention is defined by the claims appended hereto.
	abstract	The present disclosure generally relates to methods and structures for the production of radioisotopes from the thermal neutron irradiation of selected natural isotopes. The methods, structures and operations are applicable to the production of any radioisotope that may be produced from neutron irradiation.
	claims	1. An emergency core cooling system provided for a boiling water reactor plant comprising:three safety divisions for an active safety system, each of said safety divisions including a high pressure core cooling system having no less than 100% of the injection capacity required for cooling a reactor core at a design basis accident, a low pressure core cooling system having no less than 100% of the injection capacity required for cooling the reactor core at the design basis accident, a residual heat removal system, which is commonly used as the low pressure core cooling system, having no less than 100% of a heat removal capacity required for cooling the reactor core and a containment vessel at the design basis accident, and an emergency power supply source for feeding electric power to the high pressure core cooling system, the low pressure core cooling system, and the residual heat removal system; andat least one safety division for a passive safety system including an isolation condenser that cools and safely shuts down the reactor core for no less than 8 hours without replenishing cooling water even when a fire in a first safety division for the active safety system, a single failure in a second safety division for the active safety system and online maintenance in a third safety division for the active safety system occur simultaneously,wherein the active safety system does not include a pre-stage booster pump of which failure can cause a loss of whole function of one safety division. 2. The system according to claim 1, wherein the emergency power supply source provided in each of the safety divisions for the active safety system includes at least one emergency diesel generator. 3. The system according to claim 2, wherein the emergency power supply source includes at least one auxiliary gas turbine generator in each of the safety divisions for the active safety system. 4. The system according to claim 2, wherein the emergency power supply source provided in each of the safety divisions for the active safety system is connected to at least one shared gas turbine generator, said shared gas turbine generator being equipped outside of the safety divisions for the active safety system and shared among the safety divisions for the active safety system. 5. The system according to claim 1, wherein the safety division for the passive safety system further includes a passive containment cooling system. 6. The system according to claim 5, wherein the safety division for the passive safety system further includes a gravity-driven core cooling system. 7. The system according to claim 1, wherein the low pressure core cooling system provided in each of the safety divisions for the active safety system further includes a containment spray system comprising a containment spray header, a containment spray header connecting pipe, and a containment spray injection valve for spraying cooling water into the containment vessel. 8. The system according to claim 1, wherein the residual heat removal system is provided independently of the low pressure core cooling system in each of the safety divisions for the active safety system, said residual heat removal system including a containment spray system comprising a containment spray header, a containment spray header connecting pipe, and a containment spray injection valve for spraying cooling water into the containment vessel. 9. A boiling water reactor plant comprising:a reactor pressure vessel containing a reactor core;a containment vessel containing the reactor pressure vessel;an emergency core cooling system having three safety divisions for an active safety system, each of said safety divisions for the active safety system including a high pressure core cooling system having no less than 100% of the injection capacity required for cooling the reactor core at a design basis accident, a low pressure core cooling system having no less than 100% of the injection capacity required for cooling the reactor core at the design basis accident, a residual heat removal system, which is commonly used as the low pressure core cooling system, having no less than 100% of a heat removal capacity required for cooling the reactor core and the containment vessel at the design basis accident, and an emergency power supply source for feeding electric power to the high pressure core cooling system, the low pressure core cooling system, and the residual heat removal system; andat least one safety division for a passive safety system including an isolation condenser that cools and safely shuts down the reactor core for no less than 8 hours without replenishing cooling water even when a fire in a first safety division for the active safety system, a single failure in a second safety division for the active safety system and online maintenance in a third safety division for the active safety system occur simultaneously,wherein the active safety system does not include a pre-stage booster pump of which failure can cause a loss of whole function of one safety division.
	abstract	An exposure method and a semiconductor device production method that control a rise in temperature of a mask irradiated by a charged particle beam. A displacement of the position of a pattern accompanying with the rise in temperature of the mask and the pattern are projected on an exposed object with a high accuracy. After an electron beam scans one scan line, scan lines are jumped by over a number of scan lines and the electron beam scans the next scan line. Since the number of the overjumped lines is a set number that control the temperature rise of a membrane by overlapping of the electron beam, the temperature rise is controlled by an interlaced-scanning. After one interlaced-scanning, similar to the above the scan lines are jumped over by the predetermined number of scan lines and the electron beam scans the next scan lines.
	claims	1. A control rod, comprising:a tie-rod;a handle mounted to an upper end portion of said tie-rod;a connector plate mounted to a lower end portion of said tie-rod;four sheaths having a U-shaped cross-section, welded intermittently to said tie-rod at a plurality of locations of a weld portion in the axial direction of said tie-rod, extending in four directions from said tie-rod, said sheaths having an upper end in the axial direction welded to said handle and a lower end in the axial direction welded to said connector plate; anda neutron absorbing member disposed inside each of said sheaths,wherein an upper end of said weld portion located at an uppermost position in the axial direction of said tie-rod among the plurality of said weld portions between said tie-rod and said sheath in the axial direction is disposed at a position within a range between 0.8 and 13% of total axial length Ls of said sheath below an upper end of said sheath. 2. The control rod according to claim 1,wherein said upper end of said weld portion located at said uppermost position is disposed at a position within a range between 10 to 13% of said total axial length Ls below said upper end of said sheath. 3. A control rod, comprising:a tie-rod;a handle mounted to an upper end portion of said tie-rod;a connector plate mounted to a lower end portion of said tie-rod;four sheaths having a U-shaped cross-section and a plurality of projecting portions, which are welded at a weld portion to said tie-rod, protruding in a direction perpendicular to an axial core of said tie-rod being formed intermittently on a tie-rod-side end portion in an axial direction of said tie-rod, extending in four directions from said tie-rod, said sheaths having an upper end in the axial direction welded to said handle and a lower end in the axial direction welded to said connector plate; anda neutron absorbing member disposed in each of said sheaths,wherein an upper end of said weld portion located at an uppermost position in the axial direction of said tie-rod among said weld portions between said tie-rod and said plurality of projecting portions is disposed at a position within a range between 0.8 and 13% of a total axial length Ls of said sheath below the upper end of said sheath. 4. The control rod according to claim 3,wherein said upper end of said weld portion located at said uppermost position is disposed at a position within a range between 10 and 13% of said total axial length Ls below said upper end of said sheath. 5. The control rod according to claim 1,wherein said neutron absorbing member is a hafnium member. 6. The control rod according to claim 4,wherein said neutron absorbing member is a hafnium member. 7. The control rod according to claim 1, wherein the sheaths are made of stainless steel and have a plurality of apertures therein, and wherein the neutron absorbing member is disposed inside each of said sheaths so as to form a gap between said neutron absorbing member and said sheath. 8. The control rod according to claim 3, wherein the sheaths are made of stainless steel and have a plurality of apertures therein, and wherein the neutron absorbing member is disposed inside each of said sheaths so as to form a gap between said neutron absorbing member and said sheath.
	claims	1. A vented nuclear fission fuel module, comprising:a nuclear fission fuel element arranged to generate a gaseous fission product;a valve body associated with said nuclear fission fuel element, said valve body defining a plenum therein for receiving the gaseous fission product; anda valve in operative communication with the plenum for controllably venting the gaseous fission product from the plenum. 2. The vented nuclear fission fuel module of claim 1, wherein said valve body comprises a flexible diaphragm coupled to said valve for moving said valve to a closed position. 3. The vented nuclear fission fuel module of claim 1, further comprising:a cap mounted on said valve; anda manipulator arranged to extend to said cap for manipulating said cap. 4. The vented nuclear fission fuel module of claim 1, further comprising a manipulator arranged to extend to said valve for manipulating said valve. 5. The vented nuclear fission fuel module of claim 1, further comprising:an articulated manipulator arm arranged to extend to the plenum; anda receptacle carried by said articulated manipulator arm and arranged to engage with the plenum for receiving the gaseous fission product controllably vented from the plenum. 6. The vented nuclear fission fuel module of claim 1, wherein said valve is responsive to a parameter chosen from pressure in the plenum and a type of gaseous fission product in the plenum. 7. The vented nuclear fission fuel module of claim 1, further comprising a sensor in operative communication with the plenum. 8. The vented nuclear fission fuel module of claim 7, wherein said sensor senses a parameter chosen from pressure in the plenum and a type of gaseous fission product in the plenum. 9. The vented nuclear fission fuel module of claim 7, wherein said sensor comprises a sensor chosen from a radiation sensor, from a chemical sensor, and an optical sensor. 10. The vented nuclear fission fuel module of claim 7, wherein said sensor comprises a transmitter. 11. The vented nuclear fission fuel module of claim 10, wherein said transmitter is configured to transmit an identification signal identifying said valve body. 12. The vented nuclear fission fuel module of claim 1, further comprising a canister surrounding said fuel element. 13. The vented nuclear fission fuel module of claim 12,wherein said canister has a bottom portion defining a first opening; andwherein said canister has a side portion defining a second opening. 14. The vented nuclear fission fuel module of claim 13, wherein said canister comprises a tube sheet therein having a contour shaped for guiding a coolant along a coolant flow path extending from the first opening and through the second opening. 15. The vented nuclear fission fuel module of claim 13, wherein said canister comprises a ceramic tube sheet therein for dissipating heat and having a contour shaped for guiding a coolant along a coolant flow path extending from the first opening and through the second opening. 16. The vented nuclear fission fuel module of claim 1, further comprising a reservoir coupled to said valve for receiving the gaseous fission product vented by said valve. 17. The vented nuclear fission fuel module of claim 16, wherein said reservoir comprises a filter for separating a condensed phase fission product from the gaseous fission product. 18. The vented nuclear fission fuel module of claim 17, wherein said filter comprises a filter chosen from a HEPA filter, a semi-permeable membrane, an electrostatic collector, and a cold trap. 19. The vented nuclear fission fuel module of claim 1, further comprising a controller coupled to said valve for controlling operation of said valve. 20. A vented nuclear fission fuel module, comprising:a plurality of nuclear fission fuel element bundles arranged to generate a gaseous fission product;a plurality of valve bodies associated with respective ones of said plurality of nuclear fission fuel element bundles, at least one of said plurality of valve bodies defining a plenum therein for receiving the gaseous fission product;a valve disposed in the at least one of said plurality of valve bodies and in communication with the plenum for controllably venting the gaseous fission product from the plenum;a flexible diaphragm coupled to said valve for moving said valve; anda removable cap threadably mounted on said valve. 21. The vented nuclear fission fuel module of claim 20, wherein said flexible diaphragm is arranged to move said valve to a closed position. 22. The vented nuclear fission fuel module of claim 20, further comprising an articulated manipulator arm arranged to extend to said cap for threadably dismounting said cap from said valve. 23. The vented nuclear fission fuel module of claim 20, further comprising an articulated manipulator arm arranged to extend to said valve for operating said valve. 24. The vented nuclear fission fuel module of claim 20, further comprising:an articulated manipulator arm arranged to extend to the plenum; anda receptacle carried by said articulated manipulator arm and arranged to engage with the plenum for receiving the gaseous fission product vented from the plenum. 25. The vented nuclear fission fuel module of claim 20, wherein said valve is responsive to a parameter chosen from pressure in the plenum and a type of gaseous fission product in the plenum. 26. The vented nuclear fission fuel module of claim 20, further comprising a sensor in operative communication with the plenum. 27. The vented nuclear fission fuel module of claim 26, wherein said sensor senses a parameter chosen from pressure in the plenum, a type of gaseous fission product in the plenum, and a radioactive fission product in the plenum. 28. The vented nuclear fission fuel module of claim 26, wherein said sensor comprises a sensor chosen from a radiation sensor, a chemical sensor, and an optical sensor. 29. The vented nuclear fission fuel module of claim 26, wherein said sensor comprises a transmitter. 30. The vented nuclear fission fuel module of claim 29, wherein said transmitter is configured to transmit an identification signal identifying said valve body. 31. The vented nuclear fission fuel module of claim 26, further comprising a canister surrounding at least one of said plurality of nuclear fission fuel element bundles. 32. The vented nuclear fission fuel module of claim 31,wherein said canister has a bottom portion defining a flow opening; andwherein said canister has a side portion defining a flow port. 33. The vented nuclear fission fuel module of claim 32, wherein said canister comprises a tube sheet therein having a contour on an underside surface thereof shaped for guiding a coolant along a curved coolant flow path extending from the flow opening and through the flow port. 34. The vented nuclear fission fuel module of claim 32, wherein said canister comprises a ceramic tube sheet therein for dissipating heat and having a contour on an underside surface thereof shaped for guiding a coolant along a curved coolant flow path extending from the flow opening and through the flow port. 35. The vented nuclear fission fuel module of claim 20, further comprising a reservoir coupled to said valve for receiving the gaseous fission product vented by said valve. 36. The vented nuclear fission fuel module of claim 35, wherein said reservoir comprises a removable filter for separating and capturing a condensed phase fission product from the gaseous fission product. 37. The vented nuclear fission fuel module of claim 36, wherein said filter comprises a filter chosen from a HEPA filter, a semi-permeable membrane, an electrostatic collector, and a cold trap. 38. The vented nuclear fission fuel module of claim 20, wherein said valve is operable to controllably vent the gaseous fission product according to a predetermined release rate for minimizing size of an associated gaseous fission product clean-up system. 39. The vented nuclear fission fuel module of claim 20, further comprising a controller coupled to said valve for controlling operation of said valve.
	summary
	description	This application claims priority to Provisional Application Ser. No. 61/316,956, filed Mar. 24, 2010. 1. Field This invention relates to a device for transporting control rod assemblies between fuel assemblies in a facility associated with a nuclear power generation plant and, more specifically, to a device for transferring control rod assemblies among fuel assemblies that uses an overhead crane as its primary lifting mechanism. 2. Related Art Fuel for a nuclear reactor used to create steam and, ultimately, electricity, generally is in the form of fuel rods containing a fissile material. When fuel rods are being stored, the fuel rods are typically supported in nuclear fuel assemblies arranged as spaced parallel arrays. Fuel assemblies are stored in racks in a protective medium, such as water containing boric acid. In addition to the fuel rods, poison rods and/or water displacer rods are dispersed throughout the fuel assemblies to control the fission process. Poison rods generally include a plurality of elongated rods, each containing a neutron absorbent material, which fit in longitudinal openings, or thimbles, defined in the fuel assemblies. The top end of each poison rod is attached to a web or spider, thereby forming a poison rod assembly. A T-shaped bar or threaded hub is affixed to the top of the web or spider creating an easily accessible attachment point for lifting a poison rod assembly so it may be transferred from one fuel assembly to another. Because the poison rods, which are approximately 12 to 14 feet (3.66 to 4.27 meters) long, are only connected by the web or spider located at the top of the poison rod assembly, the lower end of the poison rods move freely, and, as such, can be difficult to reinsert within a second fuel assembly without the aid of a means for alignment. Prior art transfer devices provided comb assemblies as an alignment means. A comb assembly consists of at least two plates having slots corresponding to the rows of poison rods in the poison rod assembly. The plates are oriented at 90° to each other. As such, when the plates are positioned on top of each other, a grid is formed with an opening for a poison rod at each intersection of the slots. To provide extra stability, comb assemblies typically have two spaced grids. Each comb grid is typically formed of four plates, two plates with channels extending in one direction and two plates with channels extending in perpendicular direction. The plates are divided so that the comb assemblies may be moved aside while the web portion of the poison rod assembly is being lifted from the fuel assembly. Once the web portion of the poison rod assembly is above the comb assemblies, the comb assemblies are brought into place providing support and guidance for the poison rods. As shown in Hornack et al., U.S. Pat. No. 5,325,408, some prior art transfer devices use a winch located at the top of the transfer device to lift the poison rod assembly. Movement of the transfer device itself between fuel cells, is accomplished by a gantry crane in the fuel cell storage facility. Thus, this type of prior art lifting device consists of at least two lifting means, one to lift the transfer device itself, and one to lift the poison rod assembly within the transfer device. Burton et al., U.S. Pat. No. 6,327,322, recognize the advantage of the transfer device functioning with a single lifting mechanism. However, movement of the transfer device was still awkward because of the extended length of the transfer mechanism which was suspended from the gantry crane. According, a further improvement in the transfer mechanism is desired that will improve its reliability and ease of operation. The foregoing object is achieved by a transfer device for moving a control rod assembly between fuel assemblies using an overhead crane. The control rod assembly has a plurality of spaced control rods which are supported from an overhead web or spider frame which aligns the control rod with guide thimble tubes in the fuel assemblies in which the control rods are designed to be inserted. In accordance with this embodiment, the transfer device includes an upper latch tube assembly having a longitudinal axis. An elongated inner member is slidably supported within the upper latch tube assembly is operable to telescope substantially coaxially with the longitudinal axis. A gripper assembly is supported from the elongated inner member and has an actuation arm reciprocably slidably supported within the elongated inner member to move substantially along the longitudinal axis a selected distance to actuate a gripper at one end of the gripper assembly. Another end of the gripper assembly is connected to an end of the elongated inner member which at another end includes a bail which is adapted to be attached to an overhead crane. An interlock assembly is attached to the upper latch tube assembly and selectively couples the elongated inner member to the upper latch tube assembly at one or another of two elevations along the longitudinal axis, with the one elevation being in a substantially extended position and the another elevation being in a substantially retracted position. An elongated enclosure assembly extends along the longitudinal axis and has a length at least substantially equal to the height of the control rod assembly. The length of the elongated closure assembly is substantially rigidly connected to one end of the upper latch tube assembly and has another end configured to key on the top of the fuel assembly or a can in which the fuel assembly is inserted. A plurality of alignment cards are laterally disposed in a spaced, tandem array along the length of the enclosure assembly with each of the alignment cards having openings that are aligned and sized to pass a control rod of the control rod assembly, so that the control rods are withdrawn into the enclosure assembly in alignment with the guide thimble tubes of the fuel assembly. The alignment cards further include a central opening through which the gripper assembly can pass through and at least some of the alignment cards central opening is sized to pass at least a portion of the elongated inner member. Preferably, the alignment cards prevent rotation of the gripper assembly whether or not the gripper assembly is attached to a control rod assembly. Desirably, the gripper assembly includes a central body having a generally rectangular cross section profile that fits in a corresponding central opening in at least some of the alignment cards. In one embodiment, the gripper assembly includes at least one laterally extending fin that fits in a corresponding slot in at least some of the alignment cards. Preferably, the gripper assembly includes a plurality of laterally extending fins that are spaced around a circumference of the gripper assembly and are desirably, equally spaced around the circumference of the gripper assembly. In another embodiment, a distal lateral end of the fin is contoured to have an enlarged cross section that fits in a corresponding opening in at least some of the alignment cards. Preferably, the contour is round and the distal lateral end of the fin has a bullet nose in at least one end in a direction of travel of the gripper assembly. Desirably, the distal lateral end of the fin has a bullet nose in an end on either side of the direction of travel of the gripper assembly. In another embodiment, the gripper assembly is biased in a latched condition. Referring to FIG. 1, there is illustrated a spent fuel storage pool 10 which contains a plurality of spent nuclear fuel racks 12. The spent fuel pool 10 is a sealed enclosure comprised of concrete 14 and a sealed metallic liner 16. The spent fuel pool 10 is filled with a shielding medium, such as water containing boric acid 18. Each fuel rack 12 includes a plurality of vertically oriented spaced apart fuel cells 20. Each cell 20 is sized to received a fuel assembly 50 (described below). Each cell 20 has a metallic can 22 affixed to the top of the cell 20. The can 22 may include a square funnel to guide a fuel assembly 50 into its storage position. As shown in FIG. 2, the can 22 includes two bores 24, 26 in raised plates 25, 27 at diagonally opposite corners. The remaining corners of the can 22 define standoff plates 28, 30. However, it should be appreciated that the fuel assembly top nozzle may have the bores 24, 26, raised plates 25, 27 and standoff plates 28, 30, without departing from the intent of this embodiment. Referring to FIG. 2, a poison rod assembly 40 is shown partially extracted from a fuel cell 20. Each fuel assembly 50 is formed in part from fuel rods 52 which are intermixed with poison rods 42. The fuel rods 52 are generally positioned on the periphery of the fuel assembly 50 and the poison rods 42 are generally positioned in an inner portion of the fuel assembly 50. The poison rods 42 are joined at their top portions by a support web 44 which may take the form of the spider 44 illustrated in FIG. 2 or other rudimentary web form such as that described in U.S. Pat. No. 6,327,322. A hub 46 is centrally attached to the support web 44 extending upwardly, forming an easily accessible attachment point for lifting the poison rod assembly 40. When the poison rod assembly 40 is positioned within the fuel assembly 50, each poison rod 42 is disposed within a thimble 48 mounted in the fuel assembly 50 between a top nozzle 32 and a bottom nozzle which is not shown. Referring to FIG. 1, a poison rod assembly transfer device 70 of the present invention is illustrated within a spent fuel pool 10. The transfer device 70 is suspended within the spent fuel pool 10 by an overhead crane 60. The overhead crane 60 is coupled to a moveable walkway 62 and gantry 63. The moveable walkway 62 and the gantry 63 are mounted on walkway rails 64 located above the water line 18 of the spent fuel pool 10. The crane 60, moveable walkway 62 and gantry 63 are used to lift the transfer device 70 and a poison rod assembly 40 and move them between fuel cells 20. The transfer device 70 is seated on a fuel cell 20 and attached to a poison rod assembly 40 as detailed below. Though, the transfer device discussed hereafter is described with regard to the movement of a poison rod assembly, it should be appreciated that the transfer device can also be employed to move any control rod assembly, such as an annular burnable absorber assembly, water displacement rod assembly, or neutron source assembly with only a modification to the gripper attachment point to provide a compatible coupling of the transfer device to the assembly to be moved. Similarly, the transfer device may be used in the main containment of such a facility to move control assemblies within the core of a nuclear reactor, though that might not be the most efficient use of the apparatus. The transfer device 70 is shown in more detail generally in FIGS. 3, 3A, 3B and 3C, with different sections shown in more detail in the remaining figures. The transfer device 70 includes four basic sections; an upper latch tube section 100, an inner support tube assembly 200, an enclosure assembly 300 and a gripper assembly 400 which can generally be appreciate from FIGS. 3, 3A, 3B and 3C. The outer member is comprised of the upper latch tube assembly 100 and an enclosure assembly 300 which are rigidly connected at the flanges 102, 302, respectively. The enclosure assembly 300 supports and protects the poison rod assembly 40 as it is extracted from the fuel cell 20. In the preferred embodiment, the upper latch tube assembly 100 is tubular. The enclosure assembly 300 is fixed below the upper latch tube assembly 100. The enclosure assembly 300 is an appropriate length to support substantially the full length of the poison rod assembly when it is drawn within the enclosure assembly. Inner support tube assembly 200 is slidably disposed within the upper latch tube assembly 100 and the enclosure assembly 300, and is coupled at its lower end to the gripper assembly 400. The gripper assembly 400 includes a gripper 402 at its distal end that rides within the enclosure assembly 300, traveling substantially over the longitudinal length thereof. The inner support tube assembly 200 and upper latch tube assembly 100 can be selectively coupled by an interlock device 110. The interlock device 110 locks the inner support tube assembly 200 in either an upper position 202 as shown in FIG. 3C or a lower position 204 as shown in FIG. 3B. The inner support tube assembly 200 is attached to the crane 60 as shown in FIG. 1 so that, when the inner support tube assembly 200 is not coupled to the upper latch tube assembly 100 and through the upper latch tube assembly 100 to the enclosure assembly 300 and the crane 60 is raised, enclosure assembly 300 and upper latch tube assembly 100 remain stationary and the inner support tube assembly 200 and gripper assembly 400 move vertically. When the interlock device 110 is engaged, however, inner support tube assembly 200 is coupled to the upper latch tube assembly 100 and the enclosure assembly 300 and raising the crane 60 raises the entire transfer device. It should be noted that the actuator 168 that operates the gripper 402 on the gripper assembly 400, through the shaft 416 (as will be explained hereafter), has a cylinder 169 that blocks the lower latch openings 220, 222 (FIG. 9) in the inner support tube assembly 200 when the inner support tube is fully inserted in the enclosure assembly 300 and the gripper 402 is activated. In this position, (shown in FIG. 3B), the cylinder prevents the interlock 110 from latching the inner support tube 200 to the upper latch tube assembly 100. In that way, the poison rod assembly cannot be raised until it is fully supported in the enclosure assembly 300. Thus, lifting of a poison rod assembly 40 is accomplished by an operator using the crane 60 to position the transfer device 70 over a fuel cell 20 containing a poison rod assembly 40. Once the transfer device 70 is seated on the fuel cell 20, the operator uses crane 60 to lower the inner support tube assembly 200 and the gripper assembly 400 until the gripper 402 engages the hub 46 of the poison rod assembly 40. When the gripper 402 has engaged the hub 46, the operator releases the interlock 110 and uses crane 60 to lift the inner support tube assembly 200, the gripper assembly 400 and the poison rod assembly 40. Once the poison rod assembly 40 is withdrawn from the fuel cell 20, the operator may use the moveable gantry 63 to reposition the crane 60 and transfer device 70 above another fuel cell 20. The transfer device 70 is seated on the second fuel cell 20 and the poison rod assembly 40 can be inserted into the second fuel cell 20. When the poison rod assembly 40 is seated within the second fuel cell 20, the gripper assembly 400 is disengaged from the poison rod assembly 40 and the transfer device 70 is removed. As shown in FIGS. 6, 7 and 8, the enclosure assembly 300 includes two C-members 304 held in spaced relationship by a number of horizontal guide plates (also referred to as alignment cards) 306 which are supported in a spaced tandem array along the length of the C-members 304. It should be appreciated that the C-members could be replaced by four angle channels at the corners or a tubular housing. The C-members 304 define a preferably square, frame cavity 308 that has slotted guide bars 309 proximate the corners as shown in FIGS. 6 and 8. Each C-member 304 has an upper end 310, located at the enclosure assembly upper end and a lower end 312 located at the enclosure assembly lower end. At the lower end 312 of the C-members 304 is a mounting pedestal 314. The C-members 304 are attached to the mounting pedestal 314 and the mounting pedestal 314 has a central opening 316 that communicates with the central cavity 308 of the enclosure assembly 300. The mounting pedestal can be better observed from the isometric view shown in FIG. 7. The central opening 316 in the pedestal 314 is sized to allow the poison rod assembly 40 to pass therethrough. The pedestal 314 communicates with the alignment cards 306 as the poison rod assembly is withdrawn. In operation, the poison rod assembly will be lifted through the pedestal 314 and alignment cards 306 by the gripper assembly 400 into a position within the frame of the enclosure assembly cavity 308. The pedestal 314 lower surface has at least one projection 318 with the preferred embodiment having at least two projections 318 extending downwardly from diagonally opposite corners as shown in FIG. 7. The projections 318 are sized to engage the bore holes 24, 26 on the fuel rod assembly top nozzle or assembly can 22. Thus, seating the transfer device 70 on the fuel cell 20 is accomplished by the operator lowering the device 70 until the projections 318 are seated within the bore holes 24, 26. Once the projections 318 are so seated, the transfer device 70 is resting on the fuel cell can 20. The configuration of the alignment cards 306 is shown in FIG. 8 and includes a number of round openings 320 through which the poison rods pass and slots 322 through which webs on the gripper assemblies 400 slide as will be described hereafter. The alignment cards 306 also include a central opening 324 which is configured to correspond to the central body shape of the gripper assembly 400. Slotted guide bars 309 extend the full length of the C-members 304 and guide the gripper assembly 400 in between alignment cards 306. As previously mentioned, the upper latch tube assembly 100 is fixed at its lower end 102 to an upper flange 302 of the enclosure assembly 300. Thus, when the transfer device 70 is seated on a fuel cell 20, enclosure assembly 300 and, therefore, upper latch tube assembly 100 are fixed in place. As noted above, inner support tube assembly 200 is slidably disposed within the upper latch tube assembly 100 and enclosure assembly 300. Thus, as shown in FIGS. 3, 3B and 3C, when the enclosure assembly 300 and upper latch tube assembly 100 are fixed in place, the inner support tube assembly 200 can slide between the upper position 202 and the lower position 204 within the enclosure assembly 300 and the upper latch tube assembly 100. As shown in FIG. 9, a platform 206 is mounted at the upper end 208 of the inner support tube assembly 200. The lifting platform 206 includes a medial opening 210 therethrough and a lifting bail 212 disposed above the platform 206. The inner support tube assembly 200 passes through the medial hole 210 and has a flange 214 that contacts the upper surface of the platform 206. The crane 60 is attached by conventional means to the bail 212. Thus, raising or lowering the inner support tube assembly 200 or transfer device 70 is accomplished through the crane 60 acting upon platform 206. Centering rails 226 center the inner support tube in the bushing 228 (FIGS. 3B and 3C) as the inner support tube assembly 200 moves within the enclosure assembly 300. As shown in FIGS. 3C, 4, 5 and 9, the interlock device 210 allows the upper latch tube assembly 100 and, thus, the enclosure assembly 300 to be locked in either the upper position 202 or the lower position 204 with respect to the inner support tube assembly 200. In the upper position 202, the inner support tube assembly 200 is raised so that the gripper assembly 400 is adjacent to the top of the frame of the enclosure assembly 300. In the lower position 204, the gripper assembly 400 is adjacent to the lower end of the enclosure assembly 300, but, in the preferred embodiment, spaced above the mounting pedestal 314. However, it should be appreciated, that, in the lower position the gripper 402 of the gripper assembly 400 could be at or just below the mounting pedestal 314. When the inner support tube assembly 200 is in either locked position, 202 or 204, raising or lowering the crane 60 will lift or lower the transfer device 70. When the interlock device 110 is in an unlocked position, raising or lowering the crane 60 will slide the inner support tube assembly 200 and the gripper assembly 400 between the upper position 202 and the lower position 204 as shown in FIGS. 3B and 3C or allow the gripper assembly 400 to be lowered below the mounting pedestal 214 to engage a poison rod assembly 40. The interlock device 110 is located adjacent to the upper end of the upper latch tube assembly 100. The interlock device 110 includes a pair of latch members 112 and 114, and a release mechanism 116, which includes support collar assembly 118 linking members 120, 122, a double clevis 124, push rod 126, spring 128, and interlock support plate 130. Additionally, the upper latch tube assembly 100 has two openings 132 and 134, spaced 180° apart, located adjacent to the interlock device 110. Finally, inner support tube assembly 200 has an upper pair of openings 216, 218 and a lower pair of openings 220, 222, each spaced 180° apart as shown in FIG. 9. The upper openings 216 and 218, are located proximal to the upper end of the inner support tube assembly 200 and the lower openings 220 and 222 are spaced approximately 13-15 feet (4-4.6 meters), just over the length of the poison rod assembly, below the upper openings 216, 218. As will be detailed below, spring 128, cooperating with linking members 120, 122 and push rod 126 urge the latch members 112, 114 to pass through the outer openings 132, 134 and either the upper or lower inner support tube assembly openings 116, 118, 120, 122 whereupon the inner support tube assembly 200 will be locked in place relative to the upper latch tube assembly 100. Support collar 118 includes a collar 136, pin supports 138, 140, and pins 142, 144. As shown in FIGS. 4 and 5, the support collar 136 is rectangular with an offset medial opening 146 therethrough, and a plurality of fasteners 148. As shown in FIG. 5, the pin supports 138, 140 are disposed below the collar 136 held by fasteners 148 which are disposed within fasteners holes through the collar 136. It should be appreciated that although not shown in the views illustrated in FIGS. 4 and 5, the pin supports 138, 140 extend on either side of the latch members 112, 114. Each pin support 138, 140 has a flat body with a pin opening respectively for pins 142, 144 and a perpendicular mounting flange 150, 152. The mounting flanges 150, 152 incorporate threaded fastener holes which cooperate with the fasteners 148 to attach the pin supports 142, 144 below and to the collar 136. When disposed below the collar 136, the pin supports 142, 144 form pairs with aligned pin openings through which the rotatable pins 142, 144 are disposed. Each pin 142, 144 is fixed to a linking member 120, 122 and to a latch member 112, 114. In the preferred embodiment, as shown in FIG. 5, latch members 112, 114 are butterfly wing-shaped plates having a tab 154, wheels 156 which ride in wheel cavities and axles 158 which fit through mounting holes in the tab. Opposing tabs 154, one for each of the latch members 112, 114, are shaped with a convex outer edge with notches 160 between outer edges of the tabs and the tab plates. Cavities for the wheels 156 are within either tab on the latch members 112, 114. The wheels 156 are disposed within either wheel cavity and held in place by either axle 158. The wheels 156 extend beyond the outer edges of the tabs. The latch members 112, 114 are fixed to either pin 142, 144 and rotate about the pin's axis. Latch members 112, 114 are attached to the pins 142, 144 so that the tabs 154 are proximal to the housing of upper latch tube assembly 100 and so that latch members 112, 114 are disposed below the support collar 136. Referring again to FIGS. 4 and 5, interlock support plate 130 is rectangular having push rod opening 162. Interlock support plate 130 is disposed adjacent to the top of the upper latch tube assembly 100, above collar 136. Collar assembly 118 is disposed about the upper latch tube assembly 100 above openings 132, 134. Collar assembly tab opening 146 and support plate tab opening 162 are aligned vertically. Push rod 126 is slidably disposed through collar assembly tab opening 146 and support plate tab opening 162. Push rod 126 has an upper end and a lower end. A ball knob 164 is disposed at the upper end of push rod 126. Horizontal double clevis 124 is disposed at the lower end of push rod 126. Linking members 120, 122 are flat, rectangular members having a pivot hole at one end and pin mounting holes for receiving the pins 142, 144 at the opposite end. Linking members 120, 122 are rotatably coupled about the pivots on the double clevis 124, one linking member 120, 122 on either side of a double clevis 124. As stated above, linking members 120, 122 are each fixedly attached to a pin 142, 144; this attachment is through the pin mounting holes in the double clevis. Push rod 126 has a flange 166 disposed at locations spaced above collar assembly 118. Spring 128 is a helical coil spring wrapped around push rod 126 and positioned between collar 136 and flange 166, thus biasing push rod 126 upward placing the latch members 112, 114 in a normally latched position. Thus, the interlock device 110 engages the inner support tube assembly 200 and the upper latch tube assembly 100 in a similar fashion, regardless of whether the inner support tube assembly 200 is in its upper position 202 or its lower position 204. Accordingly, the following description shall address the operation of the interlock device 110 as if the inner support tube assembly 200 is in its upper position 202 and tabs 154 on the latch members 112, 114 pass through the inner support tube assembly lower openings 220, 222. It is understood, however, that the following description is equally applicable to operation of the interlock device 110 with the inner member upper openings 216, 218. If crane 60 is lifting the inner support tube assembly 200, attached to the bail 212, while tabs 254 of latch members 112, 114 pass through the inner support tube assembly 200 lower openings 220, 222, the inner support tube assembly 200 will slide within the upper latch tube assembly until the lower edge of lower openings 220, 222 of the inner support tube assembly 200 contact the notches 160 on the latch members 112, 114. When the lower edges of the lower openings 220, 222 contact the notches 160, the inner support tube assembly 200 is prevented from sliding within the upper latch tube assembly 100. At this point, raising the crane 60 will lift the entire transfer device 70 as the lifting force is transferred from the inner support tube assembly 200 through the interlock device 110 to the upper latch tube assembly 100. In operation, as push rod 126 is biased upward by spring 128, push rod 126 lifts the double clevis 124. The double clevis 124, in turn, lifts linking members 120, 122. Linking members 120, 122 act upon the pins 142, 144 which, in turn, acts upon the latch members 112, 114, biasing latch members 112, 114 toward the inner support tube assembly 200. Tabs 154 of the latch members 112, 114 pass through the openings 132, 134 in the upper latch tube assembly 100. When the inner support assembly 200 is in either its upper position 202 or its lower position 204, tabs 154 of latch members 112, 114, also pass through either inner support tube assembly 200 upper openings 216, 218 or lower openings 220, 222. Thus, when the push rods 126 is in its upper position and the openings 132, 134 in the upper latch assembly are aligned with the inner support tube assembly openings 216, 218 or 220, 222, the latch members 112, 114 are in the locked position. To release the interlock device 110 and allow the inner support tube assembly 200 to slide within the upper latch tube assembly 100, an operator must operate the release mechanism 116 by pressing the ball knob 164 which will counteract the force of the spring 128 acting on the push rod 286 and push the rod 126 into its lower position. When push rod 126 is in its lower position, push rod 126 lowers double clevis 124. Double clevis 124, in turn, lowers linking members 120, 122. Linking members 120, 122 act upon pins 142, 144 which, in turn, act upon the latch members 112, 114, rotating latch members 112, 114 away from the inner support tube assembly 200 and the upper latch tube assembly 100. Tabs 154 of latch members 112, 114 are then removed from the upper latch tube assembly 100 openings 132, 134 and either inner support tube assembly 200 upper openings 216, 218 or lower openings 220, 222. Thus, when the push rod 126 is in its upper position the latch members 112, 114 are in the unlocked position. With the latch members 112, 114 in the unlocked position, inner support tube assembly 200 can slide freely within the upper latch tube assembly 100. As the inner support tube assembly 200 slides up or down within the upper latch tube assembly 100, the inner support tube assembly 100 openings either upper or lower 216, 218 or 220, 222, will no longer be aligned with the outer member openings 132, 134. Instead, as the inner support tube assembly 200 is being raised or lowered, the outer surface of the inner support tube assembly 200 is exposed through the openings 132, 134 in the upper latch tube assembly 100. Once the outer surface of the inner support tube assembly 200 is exposed through the upper latch tube assembly 100 openings 132, 134 the operator may release the ball knob 164 and allow latch members 112, 114 to be biased by the spring 128 towards the housing of the upper latch tube assembly 100. Wheels 156 will now contact the outer surface of the inner support tube assembly 200 allowing the inner support tube assembly outer surface to slide between the latch members 112, 114. When the inner support tube assembly 200 reaches either its upper position 202 or its lower position 204, the inner support tube assembly openings, either upper or lower, 216, 218 or 220, 222, will align with the upper latch tube assembly openings 132, 134 and latch members 112, 114 will close, once again locking the inner support tube assembly 200 within the upper latch tube assembly 100. The upper portion of the inner support tube assembly 200 was described with respect to FIG. 9. FIG. 11 is a cross sectional view of the lower portion of the gripper assembly 400 which is attached through a rod extension, not shown, to the lower portion 224 of the inner support tube assembly 200. The gripper assembly includes two sets of laterally extending fins 404 and 406. Each set of fins includes four separate fins 408 that are equal distantly spaced by 90° around a central hub 410 that has a generally square cross section with the fins extending from the corners of the square central hub 410 as shown in the cross sectional view illustrated in FIG. 11. Each of the fins has an axially extended rounded distal ends that terminates axially at either end in a bullet nose. The intermediate lateral sections of the fins 414 ride in the slots 322 of the alignment cards 306 while the distal ends of the fins 412 ride in the rounded openings 320 within some of the slots 322, the central hub 410 rides in the central opening 324 of the alignment cards 306 all of which assure that the gripper assembly will maintain its orientation as it moves axially within the enclosure assembly 300. The distal ends of the fins 412 ride on the slotted guide bars 309 in between the alignment cards for continued support over the length of the enclosure assembly 300. The gripper 402 at the distal axial end of the gripper assembly 400 is activated by an axially slidable central shaft 416 which is connected to the actuator handle 168 shown in FIG. 4. The actuator handle is maintained in position by a locking pin 170. Movement of the central shaft 416 in a direction toward the gripper 402 spreads the gripper and will lock the gripper within the poison rod assembly hub 46. The design of the gripper increases actuator locking force with any increase in downward load. A spring or springs 418 are captured on either side of a spring spacer 420 and the lower spring is captured between the spacer and the central fin hub 410. The spring or springs 418 are compressed in the gripper assembly and compensate for the approximately sixty percent of the actuator rod weight, and preferably, though not shown in FIG. 10, biases the gripper 402 in a normally locked position. In operation, the transfer device 70 is seated on a fuel cell 20 as described above. For the purpose of understanding the operation of the transfer device, at this time assume that the inner support tube assembly 200 is in its lower locked position 204. The operator then releases the interlock device 110 and uses the crane 60 to lower the gripper assembly 400 onto the poison rod assembly 40. The gripper 402 will fit into the hub 46. The operator then activates the actuator handle 68 locking the hubs to the gripper and inserts the locking pin 70 to secure the connection. The operator then uses the crane 60 and the ball knob 64 to lift the inner support tube assembly 200 there by raising the gripper 402 and poison rod assembly 40 into the enclosure assembly 300 cavity 308. The interlock device 110 will not latch into the support tube 200, as a cylinder blocks the upper support tube latch opening. Once the inner support tube assembly 200 reaches its upper position 202, the interlock device 110 will engage. After the interlock device 110 has been engaged in the upper position, crane 60 lifts the transfer device 70 off the fuel cell 20. The operator then uses the gantry 64 to reposition the transfer device 70 over a different fuel cell 20. The transfer device 70 is then seated on the second fuel cell 20 as described above. Once the transfer device is seated on the second fuel cell, the operator releases the interlock device 110 by depressing the ball knob 164 and lowers the crane 60 thereby lowering the poison rod assembly 40 into the new fuel cell 20. After the poison rod assembly 40 is inserted into a second fuel cell 20, the operator releases the actuation handle 168 by withdrawing the locking pin 170 and pulling up on the handle to unlatch the poison rod assembly 40 from the gripper assembly 400. The operator then raises the crane 60 to lift the inner support tube assembly 200 until the interlock device 110 engages the lower openings 220, 222. Once the interlock device 110 is engaged in the lower openings 220, 222 in the inner support tube assembly 200, the crane 60 may lift the transfer device 70 off the fuel cell 20. Transporting the transfer device 70 in the telescoped condition with the inner support tube assembly 200 telescoped within the upper latch tube assembly 100 and the enclosure assembly 300 makes movement of the transfer device less awkward and easier to control. While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular embodiments disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any and all equivalents thereof.
055457959	description	DESCRIPTION OF PREFERRED EMBODIMENTS Laboratory tests which illustrate the decontamination method of this invention are described in detail below. A radioactively contaminated metallic object weighing approximately 200 kg, which in this laboratory test was a crane hook, was placed into an empty polypropylene tank with a capacity of approximately 300 l. The entire metal surface area of the crane hook was estimated to be approximately 2 m.sup.2. In a second step, 150 l of a 0.5% formic acid decontamination solution or agent was added to the bath. In a third step, the crane hook was left in the bath at an ambient temperature for 5 to 16 hours. Subsequently, the stoichiometrically depleted decontamination solution was pumped out. At this point the radioactivity of the used decontamination agent and the remaining radioactivity of the metallic object was measured, and the foregoing steps were repeated. These steps had to be repeated numerous times, depending on the extent of the radioactive contamination. After it was determined that the residual radioactivity of the crane hook was below the permissible threshold, the used decontamination agent was electrolytically treated in the same bath. The remaining sludge, comprising predominantly Fe, Fe (OH).sub.x, and other impurities, including the absorbed radioactivity, were solidified with cement after sedimentation and sanitized. In a final step, remaining water was then passed through an ion exchanger and subsequently delivered to a sewage treatment plant. In other laboratory tests, the time required for stripping a radioactive layer of metal from a sample of A43 steel was determined. The tests were performed on a sample weighing 200 g and having the dimensions of 50.times.100.times.5 mm. From these laboratory tests it was determined that with a decontamination solution having a very low formic acid concentration, such as 0.3 Mol/l, metallic stripping could be very precisely controlled by altering the bath temperature. Thus, it was determined, for example, that with a bath temperature of 19.degree. C. the stripping rate was 1.1 mg/cm.sup.2 .multidot.hr, while a bath temperature of 80.degree. C. produced a stripping rate of 35 mg/cm.sup.2 .multidot.hr. As in the laboratory test previously discussed, the used radioactively contaminated solution was subjected to anodic oxidation by means of electrolysis. The iron hydroxide sludge formed in this laboratory test absorbed the radioactivity. After sedimentation, the remaining water was used for further decontamination. A quantitative comparison between the method taught by U.S. Pat. No. 4,508,641 and a decontamination method according to this invention reveals that a decontamination method according to this invention produces 30 times less secondary waste than the method taught by the '641 patent. This comparison clearly shows the economic significance of the method of this invention. Although the examples cited herein utilize formic acid, the method of this invention can be performed absolutely identically using acetic acid instead of formic acid, as described, without changes regarding concentration or temperature. The two low-molecular carboxylic acids, formic acid and acetic acid, are the only carboxylic acids which are usable for this purpose. All higher-molecular carboxylic acids form complex byproducts which cause an increase in secondary waste. In the examples described hereinabove, contacting of the radioactive surfaces was performed by dipping the radioactively contaminated metallic object into a bath. Another form of contacting of the acid-containing aqueous solution with the radioactive surface comprises spreading the metallic objects to be decontaminated on a surface and drizzling or spraying the objects with the acid-containing aqueous solution. The acid-containing aqueous solution contacting the surface to be decontaminated is substantially stoichiometrically depleted of acid in the contact area. After a short reaction time, it is then possible to wash down the metallic surface with a stream of increased pressure. In the process, the substantially stoichiometrically depleted acid-containing aqueous solution is washed away, together with reaction products possibly formed on the metallic surface. Thereafter the metallic surface to be decontaminated can again be sprayed or drizzled. This treatment at intervals completely corresponds to a sequence of baths. Only a mechanical surface cleaning is performed by the spraying between two spraying or drizzling operations. This mechanical cleaning could also be achieved by brushes. The alternating drizzling and washing operations can be performed with the same acid-containing aqueous solution, which is always almost completely stoichiometrically depleted of acid in the contact area. This can be done until the entire amount of the acid-containing aqueous solution has been nearly totally stoichiometrically used up. It is preferred, in this method, that washing off the surface of the object with water is the last step. This method is usable for all mentioned metals or for alloys containing such metals. Tests of radioactive lead plates in particular have shown that this method is extremely simple and quick. The following qualitative conversion takes place during the process of this invention: EQU Pb+2 CH.sub.3 COOH+H.sub.2 O.sub.2 .fwdarw.Pb (CH.sub.3 COOH).sub.2 +H.sub.2 O+PB oxides A dark coating formed on the lead plates by this process is simply washed off by spraying. The stoichiometrically depleted solution is regenerated by separating off a sludge of Pb oxides by sedimentation, which solidifies and is processed as radioactive waste. The remaining solution is electrolytically treated in accordance with the following reactions: Reaction at the cathode: EQU Pb.sup.2+ +2e.sup.- .fwdarw.Pb.sup.o Lead precipitation Reaction at the anode: EQU COOH.sup.- +H.sup.+ .fwdarw.HCOOH Acid regeneration EQU Pb.sup.2+ +O.sub.2.sup.2- .fwdarw.PbO.sub.2 Lead oxide formation The lead precipitation products as well as the lead oxide are radioactive and are solidified with sludge and disposed of. The regenerated acid is radiation-free and suitable for reuse. It is only necessary to set the concentration again.
042740355	abstract	A field emission electron gun including a cathode, a control electrode which is disposed in the vicinity of the cathode, an anode which is disposed for accelerating electrons emitted from the cathode, and a source of a D.C. voltage to be applied between the cathode and the anode. Also, there is provided a switching arrangement capable of changing-over a potential of the control electrode between ground potential and a potential of the cathode, and an arrangement capable of varying relative positions of the cathode and the control electrode.
	abstract	Various embodiments of the invention provide devices, methods and systems, including without limitation data acquisition systems, that can provide flexible sensing and/or data acquisition solutions. An exemplary sensing device, which may be in communication with one or more computers, such as a server, etc., can include one or more sensor(s), a processor and/or a data store. The sensing device can, perhaps in response to instructions received from the computer, filter and/or otherwise process data acquired by the sensor before transmitting the desired data to the computer. The sensing device may store some or all of the acquired data locally and/or may transmit, replicate, etc. some or all of the stored data to the computer.
	description	This application claims priority to U.S. Provisional Patent Application Ser. No. 62/331,660, filed May 4, 2016, the disclosure of which is hereby incorporated by reference in its entirety. The field of the disclosure relates generally to transfer of radionuclide generators and, more particularly, to systems and methods for sanitizing transfer mechanisms of radionuclide generator column assemblies. Radioactive material is used in nuclear medicine for diagnostic and therapeutic purposes by injecting a patient with a small dose of the radioactive material, which concentrates in certain organs or regions of the patient. Radioactive materials typically used for nuclear medicine include Technetium-99m (“Tc-99m”), Indium-111m (“In-111”), Thallium-201, and Strontium-87m, among others. Such radioactive materials may be produced using a radionuclide generator. Radionuclide generators generally include a column that has media for retaining a long-lived parent radionuclide that spontaneously decays into a daughter radionuclide that has a relatively short half-life. The column may be incorporated into a column assembly that has a needle-like outlet port that receives an evacuated vial to draw saline or other eluant liquid, provided to a needle-like inlet port, through a flow path of the column assembly, including the column itself. This liquid may elute and deliver daughter radionuclide from the column and to the evacuated vial for subsequent use in nuclear medical imaging applications, among other uses. Prior to use in medical applications, radionuclide generators are sterilized such that when sterile eluant is eluted through the device, the resulting elution is also sterile and suitable for injection into a patient. Additionally, column assemblies of radionuclide generators intended for use in the medical industry generally undergo sterility testing to ensure the column assemblies are sterile and suitable for producing sterile, injectable elutions. At least some known methods of sterility testing column assemblies require an extended period of time between collection and processing of a sterility test sample, and/or excessive handling of a vial in which an elution sample is collected for use in sterility testing. These circumstances may result in false negative results and false positive results. A need exists for improved systems and methods for transferring radionuclide generator column assemblies from a production line to a clean room environment for collection of sterility test samples, and for systems and methods for sanitizing and maintaining sanitized environments in which sterility test samples are collected. This Background section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. In one aspect, a system includes a radiation containment chamber, an isolator connected to the radiation containment chamber, a rotating transfer door positioned between the radiation containment chamber and the isolator, and an antimicrobial vapor generator connected to the isolator. The rotating transfer door includes a cavity for receiving a radionuclide generator column assembly, and is rotatable between a first position, in which the cavity is open to the radiation containment chamber, and a second position, in which the cavity is open to the isolator. The transfer door is adapted to rotate while antimicrobial vapor is introduced into the isolator by the antimicrobial vapor generator. In another aspect, a method of sanitizing an isolator that is connected to a radiation containment chamber of a system for producing radionuclide generators includes introducing an antimicrobial vapor into the isolator. The system includes a rotating transfer door for transferring radionuclide generator column assemblies between the isolator and the radiation containment chamber. The method further includes rotating the transfer door while the antimicrobial vapor is circulated within the isolator. Various refinements exist of the features noted in relation to the above-mentioned aspects. Further features may also be incorporated in the above-mentioned aspects as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to any of the illustrated embodiments may be incorporated into any of the above-described aspects, alone or in any combination. Corresponding reference characters indicate corresponding parts throughout the several views of the drawings. FIG. 1 is a schematic view of a system 100 for manufacturing radionuclide generators. The system 100 shown in FIG. 1 may be used to produce various radionuclide generators, including, for example and without limitation, Technetium generators, Indium generators, and Strontium generators. The system 100 of FIG. 1 is particularly suited for producing Technetium generators. A Technetium generator is a pharmaceutical drug and device used to create sterile injectable solutions containing Tc-99m, an agent used in diagnostic imaging with a relatively short 6 hour radiological half-life, allowing the Tc-99m to be relatively quickly eliminated from human tissue. Tc-99m is “generated” via the natural decay of Molybdenum (“Mo-99”), which has a 66 hour half-life, which is desirable because it gives the generator a relatively long two week shelf life. During generator operation (i.e., elution with a saline solution), Mo-99 remains chemically bound to a core alumina bed (i.e., a retaining media) packed within the generator column, while Tc-99m washes free into an elution vial, ready for injection into a patient. While the system 100 is described herein with reference to Technetium generators, it is understood that the system 100 may be used to produce radionuclide generators other than Technetium generators. As shown in FIG. 1, the system 100 generally includes a plurality of stations. In the example embodiment, the system 100 includes a cask loading station 102, a formulation station 104, an activation station 106, a fill/wash station 108, an assay/autoclave loading station 110, an autoclave station 112, an autoclave unloading station 114, a quality control testing station 116, a shielding station 118, and a packaging station 120. The cask loading station 102 is configured to receive and handle casks or containers of radioactive material, such as a parent radionuclide, and transfer the radioactive material to the formulation station 104. Radioactive material may be transported in secondary containment vessels and flasks that need to be removed from an outer cask prior to formulation. The cask loading station 102 includes suitable tooling and mechanisms to extract secondary containment vessels and flasks from outer casks, as well as transfer of flasks to the formulation cell. Suitable devices that may be used in the cask loading station 102 include, for example and without limitation, telemanipulators 122. At the formulation station 104, the raw radioactive material (i.e., Mo-99) is quality control tested, chemically treated if necessary, and then pH adjusted while diluting the raw radioactive material to a desired final target concentration. The formulated radioactive material is stored in a suitable containment vessel (e.g., within the formulation station 104). Column assemblies containing a column of retaining media (e.g., alumina) are activated at the activation station 106 to facilitate binding of the formulated radioactive material with the retaining media. In some embodiments, column assemblies are activated by eluting the column assemblies with a suitable volume of HCl at a suitable pH level. Column assemblies are held for a minimum wait time prior to charging the column assemblies with the parent radionuclide. Following activation, column assemblies are loaded into the fill/wash station 108 using a suitable transfer mechanism (e.g., transfer drawer). Each column assembly is then charged with parent radionuclide by eluting formulated radioactive solution (e.g., Mo-99) from the formulation station 104 through individual column assemblies using suitable liquid handling systems (e.g., pumps, valves, etc.). The volume of formulated radioactive solution eluted through each column assembly is based on the desired Curie (Ci) activity for the corresponding column assembly. The volume eluted through each column assembly is equivalent to the total Ci activity identified at the time of calibration for the column assembly. For example, if a volume of formulated Mo-99 required to make a 1.0Ci generator (at time of calibration) is ‘X’, the volume required to make a 19.0Ci generator is simply 19 times X. After a minimum wait time, the charged column assemblies are eluted with a suitable volume and concentration of acetic acid, followed by an elution with a suitable volume and concentration of saline to “wash” the column assemblies. Column assemblies are held for a minimum wait time before performing assays on the column assemblies. The charged and washed column assemblies are then transferred to the assay/autoclave load station 110, in which assays are taken from each column assembly to check the amount of parent and daughter radionuclide produced during elution. Each column assembly is eluted with a suitable volume of saline, and the resulting solution is assayed to check the parent and daughter radionuclide levels in the assay. Where the radioactive material is Mo-99, the elutions are assayed for both Tc-99m and Mo-99. Column assemblies having a daughter radionuclide (e.g., Tc-99m) assay falling outside an acceptable range calculation are rejected. Column assemblies having a parent radionuclide (e.g., Mo-99) breakthrough exceeding a maximum acceptable limit are also rejected. Following the assay process, tip caps are applied to the outlet port and the fill port of the column assembly. Column assemblies may be provided with tip caps already applied to the inlet port. If the column assembly is not provided with a tip cap pre-applied to the inlet port, a tip cap may be applied prior to, subsequent to, or concurrently with tip caps being applied to the outlet port and the fill port. Assayed, tip-capped column assemblies are then loaded into an autoclave sterilizer 124 located in the autoclave station 112 for terminal sterilization. The sealed column assemblies are subjected to an autoclave sterilization process within the autoclave station 112 to produce terminally-sterilized column assemblies. Following the autoclave sterilization cycle, column assemblies are unloaded from the autoclave station 112 into the autoclave unloading station 114. Column assemblies are then transferred to the shielding station 118 for shielding. Some of the column assemblies are transferred to the quality control testing station 116 for quality control. In the example embodiment, the quality control testing station 116 includes a QC testing isolator that is sanitized prior to QC testing, and maintained at a positive pressure and a Grade A clean room environment to minimize possible sources of contamination. Column assemblies are aseptically eluted for in-process QC sampling, and subjected to sterility testing within the isolator of the quality control testing station 116. Tip caps are reapplied to the inlet and outlet needles of the column assemblies before the column assemblies are transferred back to the autoclave unloading station 114. The system 100 includes a suitable transfer mechanism for transferring column assemblies from the autoclave unloading station 114 (which is maintained at a negative pressure differential, Grade B clean room environment) to the isolator of the quality control testing station 116. In some embodiments, column assemblies subjected to quality control testing may be transferred from the quality control testing station 116 back to the autoclave unloading station 114, and can be re-sterilized and re-tested, or re-sterilized and packaged for shipment. In other embodiments, column assemblies are discarded after being subjected to QC testing. In the shielding station 118, column assemblies from the autoclave unloading station 114 are visually inspected for container closure part presence, and then placed within a radiation shielding container (e.g., a lead plug). The radiation shielding container is inserted into an appropriate safe constructed of suitable radiation shielding material (e.g., lead, tungsten or depleted uranium). Shielded column assemblies are then released from the shielding station 118. In the packaging station 120, shielded column assemblies from the shielding station 118 are placed in buckets pre-labeled with appropriate regulatory (e.g., FDA) labels. A label uniquely identifying each generator is also printed and applied to each bucket. A hood is then applied to each bucket. A handle is then applied to each hood. The system 100 may generally include any suitable transport systems and devices to facilitate transferring column assemblies between stations. In some embodiments, for example, each of the stations includes at least one telemanipulator 122 to allow an operator outside the hot cell environment (i.e., within the surrounding room or lab) to manipulate and transfer column assemblies within the hot cell environment. Moreover, in some embodiments, the system 100 includes a conveyance system to automatically transport column assemblies between the stations and/or between substations within one or more of the stations (e.g., between a fill substation and a wash substation within the fill/wash station 108). In the example embodiment, some stations of the system 100 include and/or are enclosed within a shielded nuclear radiation containment chamber, also referred to herein as a “hot cell”. Hot cells generally include an enclosure constructed of nuclear radiation shielding material designed to shield the surrounding environment from nuclear radiation. Suitable shielding materials from which hot cells may be constructed include, for example and without limitation, lead, depleted uranium, and tungsten. In some embodiments, hot cells are constructed of steel-clad lead walls forming a cuboid or rectangular prism. In some embodiments, a hot cell may include a viewing window constructed of a transparent shielding material. Suitable materials from which viewing windows may be constructed include, for example and without limitation, lead glass. In the example embodiment, each of the cask loading station 102, the formulation station 104, the fill/wash station 108, the assay/autoclave loading station 110, the autoclave station 112, the autoclave unloading station 114, and the shielding station 118 include and/or are enclosed within a hot cell. In some embodiments, one or more of the stations are maintained at a certain clean room grade (e.g., Grade B or Grade C). In the example embodiment, pre-autoclave hot cells (i.e., the cask loading station 102, the formulation station 104, the fill/wash station 108, the assay/autoclave loading station 110) are maintained at a Grade C clean room environment, and the autoclave unloading cell or station 114 is maintained at a Grade B clean room environment. The shielding station 118 is maintained at a Grade C clean room environment. The packaging stations 120 are maintained at a Grade D clean room environment. Unless otherwise indicated, references to clean room classifications refer to clean room classifications according to Annex 1 of the European Union Guidelines to Good Manufacturing Practice. Additionally, the pressure within one or more stations of the system 100 may be controlled at a negative or positive pressure differential relative to the surrounding environment and/or relative to adjacent cells or stations. In some embodiments, for example, all hot cells are maintained at a negative pressure relative to the surrounding environment. Moreover, in some embodiments, the isolator of the quality control testing station 116 is maintained at a positive pressure relative to the surrounding environment and/or relative to adjacent stations of the system 100 (e.g., relative to the autoclave unloading station 114). FIG. 2 is a perspective view of an example elution column assembly 200 that may be produced with the system 100. As shown in FIG. 2, the column assembly 200 includes an elution column 202 fluidly connected at a top end 204 to an inlet port 206 and a charge port 208 through an inlet line 210 and a charge line 212, respectively. A vent port 214 that communicates fluidly with an eluant vent 216 via a venting conduit 218 is positioned adjacent to the inlet port 206, and may, in operation, provide a vent to a vial or bottle of eluant connected to the inlet port 206. The column assembly 200 also includes an outlet port 220 that is fluidly connected to a bottom end 222 of the column 202 through an outlet line 224. A filter assembly 226 is incorporated into the outlet line 224. The column 202 defines a column interior that includes a retaining media (e.g., alumina beads, not shown). As described above, during production of the column assembly 200, the column 202 is charged via the charge port 208 with a radioactive material, such as Molybdenum-99, which is retained with the interior of the column 202 by the retaining media. The radioactive material retained by the retaining media is also referred to herein as the “parent radionuclide”. During use of the column assembly 200, an eluant vial (not shown) containing an eluant fluid (e.g., saline) is connected to the inlet port 206 by piercing a septum of the eluant vial with the needle-like inlet port 206. An evacuated elution vial (not shown) is connected to the outlet port 220 by piercing a septum of the elution vial with the needle-like outlet port 220. Eluant fluid from the eluant vial is drawn through the elution line, and elutes the column 202 containing parent radionuclide (e.g., Mo-99). The negative pressure of the evacuated vial draws eluant from the eluant vial and through the flow pathway, including the column, to elute daughter radionuclide (e.g., Tc-99m) for delivery through the outlet port 220 and to the elution vial. The eluant vent 216 allows air to enter the eluant vial through the vent port 214 to prevent a negative pressure within the eluant vial that might otherwise impede the flow of eluant through the flow pathway. After having eluted daughter radionuclide from the column 202, the elution vial is removed from the outlet port 220. The column assembly 200 shown in FIG. 2 is shown in a finally assembled state. In particular, the column assembly 200 includes an inlet cap 228, an outlet cap 230, and a charge port cap 232. The caps 228, 230, 232 protect respective ports 206, 214, 220, and 208, and inhibit contaminants from entering the column assembly 200 via the needles. Prior to final packaging, elution column assemblies of radionuclide generators intended for use in the medical industry are sterilized such that when sterile eluant is eluted through the device, the resulting elution is also sterile and suitable for injection into a patient. Known methods of sterilizing column assemblies include aseptic assembly, and autoclave sterilization of a vented column assembly. Aseptic assembly generally includes sterilizing components of the column assembly separately, and subsequently assembling the column assembly in an aseptic environment. Autoclave sterilization generally includes exposing a vented column assembly, having a column loaded with parent radionuclide, to a saturated steam, or a steam-air mixture environment. Elution column assemblies of radionuclide generators intended for use in the medical industry generally undergo sterility testing to ensure the column assemblies are sterile and suitable for producing sterile, injectable elutions. Suitable methods for sterility testing elution column assemblies include membrane filtration and direct inoculation. Direct inoculation generally involves transferring elution from an eluted vial using a syringe into a test tube containing growth media (also referred to as culture media), and incubating the test tube to determine if any viable microbial organisms exist. In membrane filtration sterility testing, a column assembly is eluted, and the eluted product liquid is passed through a sterile plastic canister containing a sterilizing filter at the canister outlet. If viable microorganisms exist in the product liquid, they are retained by the sterilizing filter inside the canister. The canister is then filled with suitable growth media (e.g., soybean-casein digest medium (TSB) or fluid thioglycollate medium (FTM)), and incubated at a target temperature for approximately 2 weeks to promote growth of any existing microbial life retained by the canister. FIG. 3 is a perspective view of an example sterility test collection kit 300. The example sterility test collection kit 300 includes an inlet needle 302 fluidly connected to two collection canisters 304 via separate fluid conduits 306, and each collection canister 304 includes a membrane filter 308 at a corresponding canister outlet 310 for retaining microbial life. To collect a sterility test specimen from an eluted vial, the inlet needle 302 is fluidly connected to the vial by piercing a septum of the inverted vial, and draining fluid from the vial into the collection canisters 304. A pump (e.g., a peristaltic pump) may be used to facilitate pumping fluid from the vial into the collection canisters 304. Collecting a sterility test sample by membrane filtration includes eluting a column assembly into a vial, draining or otherwise passing the elution liquid into at least one sterility test canister, and filling the canister with growth media after a target number of vials have been drained. Sterility canisters are then processed via incubation at temperatures appropriate for microbial growth, and observed for growth after approximately 2 weeks. Previous methods of sterility testing radionuclide generators, such as Tc-99m generators, included eluting the generators into vials, and transferring the punctured vials to a different location (e.g., a different lab) to collect and process sterility test liquid from the punctured vials. To collect the sterility test samples, the punctured vials are loaded into an isolator, and the isolator contents, including punctured vials, testing supplies, tools, isolator walls, gloves, etc. are sanitized with highly concentrated (30%-35%) vaporized hydrogen peroxide (VHP). Following VHP sanitization, sterility test samples are collected by draining punctured vials through sterility canisters, which are subsequently filled with growth media, sealed, incubated, and observed for growth after approximately 2 weeks. Prior sterility test samples are usually collected about 24 hours after an elution is collected. Prior sterility testing methods are susceptible to both false negative results, and false positive results. False negative sterility testing results can occur due to the amount of time required to collect and process sterility test samples (during which viable microorganisms are not incubated, and have no nutrient supply). False negative sterility testing results can also occur due to prolonged exposure to high radiation fields within the elution vial, which can destroy viable microorganisms. False positive sterility testing results can occur due to repeated handling of punctured vials in “dirty” environments. Methods for sterility testing radionuclide generators (e.g., Tc-99m generators) during the manufacturing and assembly process of the generator are disclosed herein. For example, methods for obtaining a sterility test sample (e.g., by membrane filtration) from a radionuclide generator during the production process are disclosed herein. These methods provide several advantages over prior sterility test methods, as described in more detail herein. Embodiments of the present disclosure facilitate immediate sterility test sample collection following sterilization and elution of radionuclide generator column assemblies. For example, embodiments of the present disclosure include sterilizing column assemblies in an autoclave, loading individual column assemblies into a tungsten transfer shield (or other suitable radiation shield, such as lead or depleted uranium), transferring the transfer shield (including the column assembly) from a negatively pressurized Grade B hot cell into a pre-sanitized, positively pressurized Grade A sterility testing isolator, removing inlet and outlet tip caps, eluting the column assembly into a sterile elution vial via sterile eluent vial (all with pre-VHP-sanitized exteriors), and immediately draining the eluted vial through at least one sterility test canister to collect the sterility test sample. Moreover, in some embodiments, tip caps are re-applied to the column assembly following sterility test sample collection, and the column assembly is re-sterilized and packaged as saleable product, or re-sterilized and re-sampled. FIG. 4 is a perspective view of an example autoclave unloading station 400 suitable for use with the system 100 of FIG. 1. FIG. 5 is a perspective view of an isolator 500 suitable for use in the quality control testing station 116 of FIG. 1. FIG. 6 is a perspective view of an interior 600 of the isolator 500. FIGS. 4-6 include arrows indicating the general process flow for collecting a sterility test sample from a column assembly. As shown in FIG. 4, the autoclave unloading station 400 includes autoclave unloading rails 402, each positioned on the downstream (i.e., unloading) side of an autoclave sterilizer (not shown in FIG. 4). In the example embodiment, the system 100 includes two autoclave sterilizers 124 (shown in FIG. 1), and the example autoclave unloading station 400 includes two sets of autoclave unloading rails 402. Each set of the autoclave unloading rails 402 receives a cart (not shown) containing up to eight racks 404 (with up to eight column assemblies 200 per rack) from one of the autoclave sterilizers 124. The cart may be removed from the autoclave sterilizers 124, and the racks 404 transferred to an autoclave unloading shuttle 406 using an autoclave unloading mechanism including, for example and without limitation, automated or semi-automated transfer mechanisms such as telemanipulators (e.g., telemanipulators 122, shown in FIG. 1) and pneumatic cylinders. The autoclave unloading station 400 also includes automated tooling 408 (also referred to as “pick-and-place” tooling) configured to automatically transfer one of the column assemblies 200 from one of the racks 404 positioned on the shuttle 406 to a transfer shield 410. The transfer shield 410 is constructed of suitable radiation shielding material including, for example and without limitation, tungsten, lead, and depleted uranium. The transfer shield 410 is operatively connected to a linear slide mechanism 412 (broadly, a transfer mechanism) configured to transfer the transfer shield 410 into a rotating transfer door 414. In the example embodiment, the linear slide mechanism 412 includes a pair of parallel rails 416 that engage a base 418 of the transfer shield 410. In operation, the transfer shield 410 is pneumatically driven by a pneumatic actuator (not shown in FIG. 4), and slides along the rails 416 into the rotating transfer door 414. The base 418 of the transfer shield 410 and the rails 416 are constructed of materials that provide a low coefficient of friction between the base 418 and the rails 416 to facilitate sliding of the transfer shield 410 on the rails 416. In the example embodiment, the rails 416 are constructed of stainless steel, and the base 418 of the transfer shield 410 is constructed of PEEK (polyetheretherketone). In other embodiments, the rails 416 and the base 418 of the transfer shield 410 are constructed of any suitable materials that enable the system 100 to function as described herein. The rotating transfer door 414 is located between the autoclave unloading station 400 and the quality control testing station 116 (shown in FIG. 1), and is configured to transfer the transfer shield 410 containing one of the column assemblies 200 between the autoclave unloading station 400 and the quality control testing station 116 (specifically, an isolator 500 of the quality control testing station 116, shown in FIG. 5). The transfer door 414 includes a cavity 420 sized and shaped to receive the transfer shield 410 therein. In FIG. 4, the transfer door 414 is shown in a first position in which the cavity 420 is open to or in communication with the autoclave unloading station 400 such that the transfer door 414 can receive the transfer shield 410 in the cavity 420. The transfer door 414 is operatively connected to a motor (not shown in FIG. 4) that causes the transfer door 414 to rotate about a vertical axis. In some embodiments, the transfer door 414 is connected to a servo-controlled motor to precisely control rotation of the transfer door 414. The transfer door 414 is rotatable between the first position (shown in FIG. 4) and a second position (not shown) in which the cavity 420 is open to or in communication with the interior 600 of the isolator 500. In operation, the transfer shield 410 is positioned within the cavity 420 of the transfer door 414 via the linear slide mechanism 412, and the transfer door 414 rotates from the first position to the second position such that the transfer shield 410 can be transferred to the isolator 500. The transfer door 414 also includes radiation shielding (not shown in FIG. 4) that maintains a minimum thickness (e.g., 6 inches) of radiation shielding between the autoclave unloading station 400 and the external environment when the transfer door 414 is rotated, regardless of the angle of rotation. In other words, the shielding of the rotating transfer door 414 maintains a minimum shielding thickness along shine paths from the autoclave unloading station 400. Suitable materials from which the radiation shielding may be constructed include, for example and without limitation, lead, tungsten, and depleted uranium. In other embodiments, the autoclave unloading station 400 may include any suitable transfer mechanism(s) that enables transfer of a column assembly 200 from the autoclave unloading station 400 to the isolator 500, including, for example and without limitation, a transfer drawer, a two door air lock system, and a telemanipulator. Although not illustrated in FIG. 4, the autoclave unloading station 400 is or includes a hot cell or radiation containment chamber such that the components of the autoclave unloading station 400 are enclosed within the radiation containment chamber. That is, the components of the autoclave unloading station 400 are enclosed within an enclosure constructed of nuclear radiation shielding material designed to shield the surrounding environment from nuclear radiation. Additionally, in some embodiments, the autoclave unloading station 400 is maintained at a Grade B or higher class clean room environment. That is, the autoclave unloading station 400 has a clean room classification of Grade B or higher. The isolator 500 includes an enclosure 502 defining the interior 600 (shown in FIG. 6), and a viewing window 504 to allow an operator to view the interior 600 of the isolator 500. The isolator 500 also includes a plurality of operator access ports 506 to allow an operator to access the interior 600 of the isolator 500, and perform operations therein. The operator access ports 506 may be sealed with suitable films or barriers (not shown in FIG. 5) to provide a seal between the exterior environment and the interior 600. The interior 600 is substantially sealed from the exterior environment to provide a relatively clean environment within which to collect and process sterility test samples. Additionally, as compared to other stations of the system 100 (e.g., the autoclave unloading station 400), the isolator 500 has relatively little or no radiation shielding. In some embodiments, for example, the enclosure 502 is constructed of metals, plastics, glass, and combinations thereof. In one embodiment, the enclosure 502 is constructed of stainless steel, PEEK, and tempered glass. Referring to FIG. 6, the isolator 500 includes a linear slide mechanism 602 configured to transfer the transfer shield 410 from the transfer door 414 and into the interior 600 of the isolator 500. In the example embodiment, the linear slide mechanism 602 is substantially identical to the linear slide mechanism 412 within the autoclave unloading station 400, and operates in substantially the same manner. The isolator 500 also includes an elution collection apparatus 604 and a sterility test sample collection system 606 configured to collect a sterility test sample from a column assembly 200 within the transfer shield 410. The elution collection apparatus 604 includes an eluant vial 608 and an evacuated elution vial (not shown in FIG. 6). The eluant vial 608 contains an eluant (e.g., a saline solution) which elutes the column assembly when fluidly connected thereto. The eluant vial 608 and the elution vial are held in an inverted position by a vial holder 610 configured to position and manipulate the vials to facilitate production of an elution sample and a sterility test sample. For example, the vial holder 610 is configured to position the eluant vial and the elution vial over the inlet port and the outlet port of the column assembly, respectively. The vial holder 610 can then be lowered such that each vial fluidly connects to a respective inlet or outlet port of the column assembly, thereby producing an elution sample within the elution vial. The vial holder 610 may be automated, semi-automated, or manually manipulated (e.g., through the operator access ports 506 in the isolator 500). The sterility test sample collection system 606 includes an inlet needle 612 fluidly connected to two collection canisters via two, separate fluid conduits (not shown in FIG. 6), and a peristaltic pump 614 configured to pump fluid from the inlet needle through the conduits and into the collection canisters. The collection canisters are enclosed within a shielded container 616 constructed of suitable radiation shielding material, including, for example and without limitation, stainless steel, lead, and tungsten. The inlet needle 612, fluid conduits, and collection canisters may have the same configuration as in the sterility test collection kit 300 shown in FIG. 3. As shown in FIG. 6, the inlet needle 612 is oriented in a vertically upward orientation. In operation, after an elution sample is collected in the elution vial, the vial holder 610 is rotated about a vertical axis to position the elution vial over the inlet needle 612. The vial holder 610 is lowered so that the elution vial septum is pierced by the inlet needle 612, which fluidly connects the elution vial with the sterility test sample collection system 606. The contents of the elution vial are then transported to the collection canisters through the fluid conduits with the assistance of the peristaltic pump 614. In other embodiments, the elution collection apparatus 604 may be omitted, and a column assembly 200 may be eluted directly into the collection canisters of the sterility test sample collection system 606. In some embodiments, for example, the sterility test sample collection system 606 may include a septum, instead of the inlet needle 612, that is pierceable by the needle-like outlet port 220 of the column assembly 200 to connect the column assembly 200 to the collection canisters. In such embodiments, the peristaltic pump 614 may be used to draw or “suck” eluent through the column assembly 200 and directly into the sterility test collection canisters without any intermediate vials. Once one or more sample have been collected in the collection canisters, growth media is added to the collection canisters, and the canisters are incubated to promote the growth of any existing microbial life retained by the canisters. The eluant and elution vials are discarded, and new tip caps are applied to the inlet port and the outlet port of the column assembly. After the sterility test sample is collected, the column assembly is transferred back to the autoclave unloading station 400 via the rotating transfer door 414. Specifically, the linear slide mechanism 602 of the isolator 500 slides the transfer shield 410 into the rotating transfer door 414 (shown in FIG. 4), and the transfer door 414 rotates from the second position (not shown) to the first position (shown in FIG. 4) such that the cavity 420 of the transfer door 414 is open to the autoclave unloading station 400. FIG. 7 is another perspective view of the autoclave unloading station 400, including arrows indicating the general process flow of a column assembly when the column assembly is returned to the autoclave unloading station 400 from the isolator 500. When the transfer door 414 is rotated to the first position (shown in FIG. 7), the transfer shield 410 is pulled or otherwise transferred out of the cavity 420 along rails 416, and the automated tooling 408 transfers the column assembly from the transfer shield 410 to a rack positioned on the autoclave unloading shuttle 406. In some embodiments, the column assembly is loaded into one of the autoclave sterilizers 124 (shown in FIG. 1), re-sterilized, and returned to the radionuclide generator production line. The column assembly may then be transferred back to the isolator 500 for additional sterility testing, or transferred to the shielding station 118 to be packaged for sale. In other embodiments, the column assembly may be discarded following collection of a sterility test sample. Embodiments of the systems and methods described herein facilitate collection of a sterility test sample in a relatively clean environment, and within a relatively short amount of time following production of a sterilized column assembly. In some embodiments, for example, a sterility test sample is collected from a column assembly within 4 hours of sterilization, within 2 hours of sterilization, or even within 1 hour of sterilization. Additionally, in some embodiments, a sterility test sample is collected from a column assembly within 7 hours of the column assembly being charged with a parent radionuclide, within 5 hours of the column assembly being charged, or even within 4 hours of the column assembly being charged. An example method of collecting a sterility test sample from a column assembly includes sterilizing a column assembly with a sterilizer (e.g., one of the sterilizers 124), the column assembly including a column having a parent radionuclide contained therein, transferring the column assembly from the sterilizer to a first clean room environment (e.g., the autoclave unloading station 400), transferring the column assembly from the first clean room environment to a second clean room environment (e.g., the isolator 500), and collecting a sterility test sample from the column assembly within the second clean room environment. In some embodiments, the first clean room environment is negatively pressurized, and the second clean room is positively pressurized. Further, in some embodiments, the first clean room environment has at least a Grade B clean room classification, and the second clean room environment has a Grade A clean room classification. Additionally, in some embodiments, such as the embodiment shown in FIGS. 4-7, a column assembly is transferred directly from the sterilizer to the first clean room environment, and directly from the first clean room environment to the second clean room environment to collect the sterility test sample. Another example method of collecting a sterility test sample from a column assembly includes transferring a column assembly from a radionuclide generator production line to an isolator, collecting a sterility test sample from the column assembly within the isolator, and returning the column assembly to the radionuclide generator production line. An example system suitable for carrying out methods of this disclosure includes a sterilization station (e.g., sterilization station 112) including at least one autoclave sterilizer (e.g., autoclave sterilizer 124), a hot cell or radiation containment chamber (e.g., autoclave unloading station 400) adjoining the sterilization station and enclosing a first clean room environment, and an isolator (e.g., QC sampling isolator 500) connected to the hot cell and enclosing a second clean room environment. In some embodiments, the first clean room environment has a clean room classification of Grade B or higher, and includes an autoclave unloader configured to remove the column assembly from the autoclave sterilizer. Additionally, in some embodiments, the isolator has a clean room classification of Grade A, and includes a sterility test sample collection system for collecting a sterility test sample from a radionuclide generator column assembly. Moreover, in some embodiments, the hot cell is negatively pressurized, and the isolator is positively pressurized. The systems and methods of the present disclosure provide several advantages over known sterility testing procedures and systems. For example, embodiments of the disclosed systems and methods facilitate minimizing false negative sterility test results by reducing the time between column assembly production and sterility testing. Embodiments of the present disclosure include eluting radioactive liquid from column assemblies into vials, immediately draining the contents of the eluted vials into sterility testing canisters, adding growth media to the canisters, and incubating the canisters within a relatively short time after elution. Minimizing the time between elution collection and sterility testing facilitates detection of viable microorganisms present in the column assembly. Other methods wait up to 24 hours post-elution before starting the sterility testing process. During that time, living microorganisms present in the column assembly elution may die from lack of nutrients, or die from high background radiation present in the elution, resulting in a false negative sterility test result. Embodiments of the disclosed systems and methods also facilitate minimizing false positive sterility test results by reducing the amount of handling and exposure to relatively dirty environments as compared to prior sterility test methods. For example, because elutions are collected and immediately drained within a sanitized Grade A environment, methods and systems of the disclosure facilitate minimizing the possibility of a false positive sterility test result caused by external contamination from repeated handling of punctured vials in dirty environments. Additionally, the systems and methods of the present disclosure facilitate reuse of column assemblies that are used for quality control (i.e., sterility testing). For example, because new tip caps are applied to column assembly inlet and outlet ports within a Grade A clean room environment after sterility test samples are collected, the column assemblies can be re-sterilized and sold, or re-sampled in the isolator. Also, embodiments of the systems and methods described provide an asynchronous pipeline that facilitates continued production of saleable generators even if sterility testing equipment is temporarily inoperable. For example, if sterility testing equipment or transfer equipment temporarily prevents the transfer of column assemblies from the autoclave unloading station to the sterility testing isolator, column assemblies targeted for quality control sterility sampling can be held in a buffer area (e.g., between the autoclave unloading rails shown in FIG. 4, or on a semicircular buffer near the left-most pick and place station shown in FIG. 4), while other column assemblies not targeted for QC sampling are transported to final packaging. Because the sampling pipeline is asynchronous, the system and methods facilitate minimizing delays that might otherwise impact process throughput. In addition to systems and methods for sterility testing of radionuclide generator column assemblies, the present disclosure also provides systems and methods for sanitizing the environment in which sterility test samples are collected, as well as systems and methods for transferring column assemblies to a pre-sanitized environment. For example, prior to sterility test sample collection, the isolator 500 may be sanitized with an antimicrobial vapor (e.g., vaporized hydrogen peroxide). The autoclave unloading station 400 may also be sanitized with an antimicrobial vapor prior to sterility test sample collection. Further, in some embodiments, the isolator 500 is positively pressurized (has a higher pressure) relative to the surrounding environment and/or relative to the adjoining autoclave unloading station 400, and has a clean room classification higher than the adjoining autoclave unloading station 400 (e.g., Grade A) to minimize the potential for external viable contamination that may otherwise cause a false positive sterility test result. Systems and methods for transferring column assemblies between a negatively pressurized hot cell and a positively pressurized isolator are provided. The systems and methods described herein facilitate maintaining the cleanliness of the isolator and the hot cell, and improving the accuracy of sterility test results, as described in more detail herein. Additionally, embodiments of the system and methods described herein facilitate sanitization of the isolator and hot cell prior to sterility test sample collection. FIG. 8 is a top view of the rotating transfer door 414 between the autoclave unloading station 400 and the isolator 500 of the quality control testing station 116. Walls of the autoclave unloading hot cell 400 and the isolator enclosure 502 are omitted in FIG. 8. As shown in FIG. 8, the rotating transfer door 414 is enclosed within an enclosure 802 constructed of radiation shielding material. More specifically, the rotating transfer door 414 is housed within an enclosure cavity 804 defined by the enclosure 802. The spacing between the rotating transfer door 414 and the enclosure 802 is greatly exaggerated in FIG. 8 for illustrative purposes. The actual spacing between the rotating transfer door 414 and the enclosure 802 is relatively small such that, in some embodiments, air flow from the isolator interior 600 into the autoclave unloading station 400 is relatively small compared to a unidirectional downward airflow in each of the isolator interior 600 and the autoclave unloading station 400. In the example embodiment, the enclosure 802 is constructed of lead clad in stainless steel, although the enclosure 802 may be constructed of any other suitable radiation shielding material, including, for example and without limitation, tungsten and depleted uranium. The enclosure 802 defines a first access opening 806 and a second access opening 808. The first access opening 806 provides access to the enclosure cavity 804 from the autoclave unloading station 400, and the second access opening 808 provides access to the enclosure cavity 804 from the isolator 500. In this embodiment, a guillotine-style sealing door 810 is positioned within the autoclave unloading station 400 and between the autoclave unloading station 400 and the transfer door 414. The sealing door 810 is configured to seal off the first access opening 806 such that the transfer door 414 and the isolator 500 are isolated from the autoclave unloading station 400. The sealing door 810 is moveable from a first, opened position to a second, closed position in which the sealing door 810 covers the first access opening 806 and occludes the rotating transfer door 414. In some embodiments, the sealing door 810 includes an inflatable sealing gasket that extends around the first access opening 806, and sealingly engages the enclosure 802 and/or a flange on the transfer door 414 to seal off the transfer door 414 and the isolator 500 from the autoclave unloading station 400. The rotating transfer door 414 includes a circular base 812 and a radiation shield 814 mounted to and extending upwards from the base 812. The radiation shield 814 is constructed from lead clad in stainless steel in the example embodiment, although the radiation shield 814 may be constructed of any other suitable radiation shielding material, including, for example and without limitation, tungsten and depleted uranium. The radiation shield 814 defines the cavity 420 in which the transfer shield 410 is received. In the example embodiment, the transfer door radiation shield 814 is U-shaped, and defines a U-shaped cavity for receiving the transfer shield 410. In other embodiments, the radiation shield 814 may have any suitable shape that enables the system 100 to function as described herein. In the example embodiment, the transfer door base 812 has a diameter of about 18 inches and the transfer door radiation shield 814 has a maximum thickness of about 12 inches. Additionally, the sides or wings of the radiation shield 814 each have a thickness of about 3 inches. The radiation shield 814 thereby provides at least 6 inches of radiation shielding between the autoclave unloading hot cell 400 and the isolator 500, regardless (i.e., irrespective) of the angle of rotation of the transfer door 414. In other embodiments, the transfer door base 812 and the radiation shield 814 may have any suitable dimensions that enable the system 100 to function as described herein. In some embodiments, the transfer door 414 may have a total weight, including the radiation shield 814, of at least 400 pounds, at least 600 pounds, at least 700 pounds, at least 800 pounds, at least 900 pounds, at least 1000 pounds, and even up to 1500 pounds. To facilitate rotation of the transfer door 414, the transfer door base 812 is rotatably supported by a bearing assembly, shown in FIGS. 9 and 10. As shown in FIGS. 9 and 10, the example bearing assembly includes a lower bearing 902 and an upper bearing 904. In the example embodiment, the upper and lower bearings 902, 904 are both tapered roller bearings, although one or both of the lower bearing 902 and the upper bearing 904 may be other than a tapered roller bearing in other embodiments. The lower bearing 902 is disposed between the transfer door base 812 and a bottom 906 of the enclosure 802. The upper bearing 904 is connected to an upper support shaft 908 that extends through a top 910 of the enclosure 802 and into the enclosure cavity 804. The upper bearing 904 is disposed between a top 912 of the transfer door 414 and the upper support shaft 908. The taper of the upper roller bearing 904 acts as a centering device to center the transfer door 414 when the lower bearing 902 is raised into engagement with the transfer door base 812. The lower bearing 902 supports the majority of the transfer door weight, and the moment load of the transfer door 414 is distributed between the lower bearing 902 and the upper bearing 904. As shown in FIG. 10, in this embodiment, an outer ring 1002 of the lower bearing 902 bears against a flanged sleeve 1004 at the enclosure bottom 906, and an inner ring 1006 of the lower bearing 902 bears against the transfer door base 812 while centered on a removable shaft 1008. In some embodiments, the bearing assembly provides sufficient freedom of rotation of the transfer door 414 such that the transfer door 414 can be precisely rotated with a servo-controlled motor 914 (shown in FIG. 9). The transfer door 414 door may be rotated at any suitable rotation rate that enables the system 100 to function as described herein. In some embodiments, for example, the transfer door 414 is rotated by the motor 914 at a rate of between about 0.5 inches per second and about 1.5 inches per second, or between about 1.5 revolutions per minute and about 2.5 revolutions per minute. In some embodiments, the transfer door 414 is rotated by a motor at a rate of about 1.0 inches per second, or about 2 revolutions per minute. Referring again to FIG. 8, the transfer door 414 also includes a pair of rails 816 mounted to the transfer door base 812 and positioned within the cavity 420. The transfer door rails 816 are aligned with the rails 416 of the linear slide mechanism 412 in the autoclave unloading station 400, and are spaced from the linear slide mechanism rails 416 in a longitudinal direction. The transfer door rails 816 are spaced from the linear slide mechanism rails 416 by a distance less than a diameter of the transfer shield base 418 such that the transfer shield 410 can slide along the rails and be transferred between the transfer door rails 816 and the linear slide mechanism rails 416. The distance or spacing between the transfer door rails 816 and the linear slide mechanism rails 416 is also large enough to receive the sealing door 810 positioned within the autoclave unloading hot cell 400. As shown in FIG. 8, the linear slide mechanism 412 of the illustrated embodiment includes a shaft 818 and a retaining clip 820 connected to a distal end of the shaft 818 for engaging the transfer shield base 418. The shaft 818 is operatively connected to an actuator (e.g., a pneumatic cylinder, not shown) to linearly displace the shaft 818 in a longitudinal direction. The shaft 818 is driven by the actuator in forward and backward directions to transfer the transfer shield 410 in and out of the transfer door cavity 420. To transfer a column assembly from the autoclave unloading station 400 to the isolator 500, the column assembly is placed in the transfer shield 410, and the transfer shield 410 is slid along linear slide mechanism rails 416 by the linear slide mechanism 412. In particular, the retaining clip 820 engages the transfer shield base 418, and the shaft 818 is driven in the forward direction by the actuator to slide the transfer shield 410 along linear slide mechanism rails 416 and transfer door rails 816. When the transfer shield 410 is positioned within the transfer door cavity 420, the transfer door 414 is rotated from the first position (shown in FIG. 8) to the second position by the motor 914 operatively connected to the transfer door base 812. When the transfer door 414 is in the second position, the linear slide mechanism 602 within the isolator 500 removes the transfer shield 410 from the transfer door cavity 420 by sliding the transfer shield 410 along rails 822 within the isolator 500. Once the transfer shield 410 is positioned within the isolator 500, a sterility test sample may be collected from the column assembly within the transfer shield 410. As noted above, the isolator 500 may be sanitized with an antimicrobial vapor (e.g., vaporized hydrogen peroxide) prior to sterility test sample collection. In some embodiments, the rotating transfer door 414 is configured to facilitate sanitization of all surfaces of the rotating transfer door 414, including interior surfaces defining the transfer door cavity 420, and exterior surfaces of the transfer door 414. In some embodiments, for example, the transfer door 414 is configured to rotate during the sanitization process. As the transfer door 414 rotates during sanitization, interior and exterior surfaces are exposed to the isolator opening (i.e., the second access opening 808), and are thereby exposed to VHP being circulated within the isolator 500. In some embodiments, the transfer door 414 is rotatable 360° about its vertical rotation axis. This allows the transfer door 414 to be rotated by at least one complete revolution during a sanitization process such that the entire exterior surface of the transfer door 414 is exposed to the antimicrobial vapor during the sanitization process. Additionally, in the illustrated embodiment, the enclosure 802 surrounding the transfer door 414 includes air returns 824 fluidly connected to the enclosure cavity 804 in which the transfer door 414 is housed. The air returns 824 extend through the enclosure 802 and into the enclosure cavity 804. The air returns 824 may connect to the enclosure cavity 804 at any suitable location that enables the system 100 to function as described herein. In the illustrated embodiment, the air returns 824 are connected to the enclosure cavity 804 along opposing sides of the enclosure cavity 804 at approximately a vertical mid-point of the enclosure 802, and proximate to the autoclave unloading cell side of the enclosure 802. The air returns 824 facilitate fluid flow between the isolator interior 600 and the enclosure cavity 804, and thereby facilitate fluid flow around the exterior of the transfer door 414 and within the transfer door cavity 420. The air returns 824 may be connected to a recirculation device (e.g., a fan, blower, or pump) via a fluid conduit to create a localized negative pressure within the enclosure cavity 804 to draw antimicrobial vapor within the enclosure cavity 804 during an isolator sanitization process. The example embodiment includes two air returns 824, although other embodiments may include more or less than two air returns. Moreover, in some embodiments, multiple air returns may be connected together (using, for example, a wye) upstream of a VHP return unit. In some embodiments, the isolator 500 is sanitized prior to the sterility test sample collection by circulating an antimicrobial vapor, such as vaporized hydrogen peroxide (VHP) within the isolator interior 600 using a suitable a fluid handling system. FIG. 11 is a schematic view of the isolator 500 and an example fluid handling system 1100 suitable for circulating antimicrobial vapor (e.g., VHP) within the interior 600 of the isolator 500 and the transfer door 414 (FIG. 8). In this embodiment, the isolator 500 includes a plurality of vapor inlets 1102 near the top of the isolator 500, and a plurality of recirculating outlets 1104 near the bottom of the isolator 500. The vapor inlets 1102 are connected to a return air duct 1105 in parallel with a suitable antimicrobial vapor generator 1106 via a fluid conduit 1108. The outlets 1104 are connected to the return air duct 1105 in parallel with the antimicrobial vapor generator 1106 via a fluid conduit 1112. The fluid handling system 1100 includes at least one recirculation device 1110 to recirculate air and the antimicrobial vapor within the isolator interior 600. In this embodiment, the fluid handling system 1100 includes two recirculation devices 1110, each connected upstream of a respective vapor inlet 1102. The recirculation devices 1110 are also connected to the return air duct 1105, the fluid conduit 1112, and the air returns 824. The antimicrobial vapor generator 1106 may include, for example and without limitation, a VHP generator. The recirculation device 1110 may include, for example and without limitation, a blower, a fan, and a pump. In this embodiment, each of the recirculation devices 1110 includes a fan. Further, in this embodiment, the air returns 824 are fluidly connected to the recirculation devices 1110 via the fluid conduits 1108 and 1112 and the return air duct 1105, such that operation of the recirculation devices 1110 generates a localized negative pressure within the enclosure cavity 804 (shown in FIG. 8), thereby drawing antimicrobial vapor towards and into the enclosure cavity 804. In this embodiment, the air returns 824 are connected to the isolator recirculation devices 1110 to recirculate antimicrobial vapor within the isolator 500 during the sanitization process. In other embodiments, the air returns 824 are connected to a different, dedicated recirculation device. The antimicrobial vapor may be recirculated within the isolator interior 600 for any suitable amount of time. In some embodiments, the transfer door 414 is rotated during the isolator sanitization process. In other words, the transfer door 414 is rotated while antimicrobial vapor is circulated within the isolator interior 600. The transfer door 414 may be rotated by at least one complete revolution during the sanitization process such that the entire exterior surface of the transfer door is exposed to the antimicrobial vapor. An example method of sanitizing the isolator 500 includes sealing the isolator 500 from the surrounding environment (including the adjoining autoclave unloading station 400), and recirculating VHP within the isolator interior. In some embodiments, sealing the isolator 500 includes lowering (or otherwise moving) the sealing door 810 to the second position, and inflating the inflatable gasket to seal off the isolator 500 and transfer door 414 from the autoclave unloading hot cell. In some embodiments, the method also includes rotating the transfer door 414 during the isolator sanitization process (i.e., while VHP is circulated or recirculated within the isolator interior). In some embodiments, the transfer door 414 is rotated at least one complete revolution, at least two complete revolutions, at least three complete revolutions, and even up to five complete revolutions while VHP is circulated within the isolator interior. In other embodiments, the transfer door 414 may be rotated any number of complete or partial revolutions that enables the system 100 to function as described herein. Moreover, in some embodiments, the transfer door 414 is continuously rotated during the sanitization process (e.g., while VHP is circulated within the isolator 500) at a suitable rate such that the transfer door 414 rotates a desired number of revolutions (e.g., 1, 2, 3, 4, or more revolutions) during the sanitization process. In some embodiments, for example, the transfer door 414 is continuously rotated at a rate of between about 1.5 revolutions per minute and about 2.5 revolutions per minute during the sanitization process (e.g., while VHP is circulated within the isolator 500). Moreover, in some embodiments, the method includes drawing VHP through the air returns 824 in the enclosure 802 using a suitable pump, fan, or blower fluidly connected to the air returns 824 Another example method of sanitizing the isolator 500 includes: a) lowering the guillotine-style sealing door 810; b) inflating the inflatable gasket to seal off the isolator 500 and the transfer door 414 from the autoclave unloading hot cell; c) stabilizing the temperature in the isolator 500; d) dehumidifying the isolator (e.g., down to about 10% humidity); e) introducing VHP into the isolator interior with a VHP generator; f) rotating the transfer door 414 while the VHP is circulated through the isolator interior; g) circulating the VHP through the enclosure cavity 804 via the air returns 824 to circulate around the exterior surface of the transfer door 414 as the exterior surface rotates past the second access opening 808 to the isolator 500; h) recirculating the VHP within the isolator interior for a set exposure time (e.g., 40 minutes); i) aerating the isolator interior; j) rotating the transfer door 414 while the isolator interior is aerated; and k) orienting the transfer door in the second position (i.e., where the transfer door cavity 420 is open to the isolator 500) at the end of the sanitization process. In some embodiments, the autoclave unloading station 400 may also be sanitized before, during, or after the isolator 500 is sanitized. For example, the autoclave unloading station 400 is VHP sanitized while the sealing door 810 is in the closed position (e.g., while the isolator 500 is being sanitized). Moreover, in some embodiments, the sealing door 810 is maintained in the closed position until both the isolator 500 and the autoclave unloading station 400 are sanitized to prevent, for example, dirty air from an unsanitized isolator to blow into a sanitized hot cell. Embodiments described above facilitate immediate collection of sterility test samples by providing a transfer mechanism between an autoclave unloading hot cell and an isolator in which sterility test samples are collected. In particular, some embodiments include a rotating transfer door airlock system that facilitates transfer of radionuclide generator column assemblies from the autoclave unloading hot cell to the isolator. Embodiments of the rotating transfer door airlock system provide a suitable amount of radiation shielding regardless of the rotational position of the transfer door. Additionally, embodiments of the rotating transfer door airlock system facilitate maintaining a positive pressure within the isolator, and a negative pressure within the autoclave unloading hot cell connected to the isolator by restricting most airflow between these two spaces. Airflow between a Grade A isolator and a Grade B autoclave unload hot cell is relatively small and constant regardless of the rotational position of the transfer door, which facilitates maintaining downward unidirectional airflow within each of the isolator and the hot cell, even during product transfers. Embodiments of the rotating transfer door also facilitate maintaining the clean room class of the isolator by maintaining the isolator at a positive pressure and the autoclave unloading cell at a negative pressure, and thereby inducing airflow only from the Grade A isolator to the Grade B autoclave unloading cell. Further, because the interstitial gap through the rotating transfer door and the enclosure or housing is small, airflow between the Grade A isolator and the Grade B autoclave unloading cell is relatively small with respect to the downward unidirectional airflow within each of the isolator and the autoclave unloading cell. Moreover, regardless of rotational position, operation of the rotating door does not disrupt unidirectional airflow in either area, which helps maintain particulate levels in both areas, even during product transfers. For example, the rotating transfer door facilitates avoiding abrupt pressure changes between the isolator and the autoclave unloading cell, which might otherwise disrupt unidirectional downward air flow. Other transfer mechanisms, such as transfer drawers and air locks, can affect unidirectional air flow within areas as drawers or air lock doors are opened and closed, for example, by creating abrupt pressure changes within adjoining cells, resulting in air flow disturbances as air rapidly flows out of one cell and into the other. Drawers and air locks also transfer significantly more air between environments (e.g., from a Grade B environment into a Grade A environment) than is transferred using a rotating door with unidirectional continuous airflow from a Grade A to a Grade B environment. Additionally, embodiments of the rotating transfer door facilitate sanitizing the isolator, as well as all surfaces of the transfer door exposed to the isolator. In particular, embodiments of the rotating transfer door are configured to rotate while an antimicrobial vapor is circulated through the isolator, thereby exposing the entire interior and exterior surfaces of the rotating transfer door to the antimicrobial vapor. Additionally, embodiments of the rotating transfer door include one or more air returns that draw air, including antimicrobial vapors, into the space surrounding the rotating transfer door, thereby exposing the interstitial space surrounding the rotating transfer door to the antimicrobial vapor. When introducing elements of the present invention or the embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. As various changes could be made in the above constructions and methods without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
048805599	abstract	Disclosed is a method of decontaminating the metal surfaces in the cooling system of a nuclear reactor by contacting the metal surfaces with an aqueous solution containing about 0.5 to about 3% of a ceric acid which can be tetrasulfato ceric acid, hexasulfamato ceric acid, hexaperchlorato ceric acid, or mixtures thereof, and about 1 to about 5% of an inorganic acid that forms a complex with the ceric acid.. The cerium III in the aqueous solution can be oxidized to cerium IV to increase the life and effectiveness of the solution. After oxidation, the aqueous solution can be passed through a hydrogen form cation exchange column to remove metal ions. If the aqueous solution contains uranyl or plutonyl ions these can be recovered by extraction for use in making fuel.. Also disclosed is a decontaminating solution of water containing about 0.5 to about 3% of a ceric acid which can be tetrasulfato ceric acid, hexasulfamato ceric acid, hexaperchlorato ceric acid, or mixtures thereof, and about 1 to about 5% of an inorganic acid that forms a complex with the ceric acid.
050698613	abstract	The apparatus comprises a pole (32), a C-shaped frame (34) fastened to one end of the pole (32) and having two branches (35, 36) substantially parallel to one another and an adjoining part (37) between the two branches, an extraction screw (40) engaged in an internally threaded hole passing through one branch (35) of the frame (34) and having one end forming a punch (50) directed towards lthe inside of the frame (34), and a means (43) for the remote actuation of the extraction screw (40) by screwing or unscrewing. The apparatus also possesses a centring ring (47) arranged round a smooth part of the extraction screw located between its threaded part and its end (50) forming the punch. Unscrewing is carried out by exerting a torque about the axis of the screw (16a) to be extracted, by means of the pole (32) and the frame (34), after the extraction screw has been tightened. The apparatus can be used particularly for carrying out the unscrewing and extraction of screws for the fastening of springs (27) of the fuel assembly of a nuclear reactor.
	summary
	description	The invention relates to a method for dismantling a steam generator or heat exchanger, in particular a steam generator or heat exchanger of a nuclear power plant. Such steam generators or heat exchangers include a plurality of primary circuit tubes with contaminated inner tube surfaces, one or more of said tubes being closed with a respective plug at both ends. The nuclear reactor of a nuclear power plant contains the reactor core, which consists of fuel elements in which nuclear energy is released through controlled nuclear fission and radioactive decay and is converted into heat. This heat heats a coolant which is pumped through the reactor thereby carrying the energy out of the reactor. The coolant is then supplied to a steam generator, and the generated steam drives the turbines of the power plant. The steam generator transfers the heat of the reactor coolant to the water-steam circuit. Configured as tube bundle heat exchangers, these steam generators convert feed water into live steam for driving the turbines. The collecting chamber is connected to the main coolant lines of the reactor cooling system via inlet and outlet nozzles. Coming from the collecting chamber, the reactor coolant flows through the tubes while emitting heat and reaches the outlet chamber, from where it is supplied to the main coolant pump. The tube bundle is connected to the tube sheet of the steam generators. The tubes of a steam generator may be up to 20 meters in length. In natural circulation, the entering feed water flows upward inside the tube bundle. In the steam dome located above the tube bundle, the residual steam moisture is separated, and the dried steam is then led out via the outlet nozzle. In nuclear power plants, the inner surfaces of the tubes of the steam generators are contaminated during operation of the plant. The integrity of the tubes is ensured through regular inspections. If an inspection reveals damage such as a reduced wall thickness, both sides of the affected tube, i.e. the inlet end as well as the outlet end, are sealed with plugs in the region of the tube sheet as a precaution. As a result, the surface contamination is also encapsulated. When the steam generator is dismantled, the tubes are decontaminated in a preceding step, for example through mechanical or chemical processes. Since the tubes which have been sealed with the plugs are not accessible to such decontamination, the problem arises that these tubes cannot be processed further, i.e. dismantled, without additional steps. The object of the invention is therefore to provide a method which prevents contaminations present on the inner surfaces of the tubes from escaping from the tubes during dismantling of the steam generator or heat exchanger. This object is achieved with a method for dismantling a steam generator or heat exchanger comprising the features according to claim 1. Advantageous configurations and modifications are specified in the respective dependent claims. The method according to the invention comprises the steps of: a) opening one or both ends of each sealed tube by creating an opening in the respective plug or by removing the respective plug; b) introducing a viscous polymer which will cure inside the tube into the initially sealed and now opened tubes, said polymer filling the tube across the full tube cross-section at least in the region of the tube ends and immobilizing contaminations in the filled portion inside the tube; c) detaching the tubes provided with polymer after the polymer has cured, the detached tubes being sealed by the cured polymer; d) sorting out the detached tubes provided with the polymer. By introducing a polymer which cures inside the tubes, the loose contamination is retained inside the tube and cannot escape when the tube is detached. In the close-down of nuclear power plants, it has become a widely established practice to perform a so-called “full system decontamination” as a last step before shutdown. Since radioactive waste is very expensive, attention needs to be paid to creating a minimum amount of “highly radioactive waste”. The open tubes which are not provided with plugs and the sealed tubes filled with the polymer belong to different waste categories, so that the sealed tubes filled with the polymer are sorted out and disposed of separately from the open tubes that are not provided with plugs. The advantages of the invention consist in particular in the fact that any type of chemical or mechanical treatment of the contaminated tubes can be avoided through the method according to the invention. Due to the damage already existing in the tubes, such a treatment of the tubes always involves the risk that the tubes will break and thereby cause contamination to be carried over to the secondary side. Such a carry-over of contamination is to be avoided by all means since the secondary side is strictly free of contamination. A further advantage of the invention is that the method is, on the one hand, much more cost-effective than known alternative methods and, on the other hand, provides a high level of safety. According to an advantageous modification of the invention, a cross-linking polymer is used, in particular a polymer which performs cross-linking through polyaddition and consists of or comprises, for example, silicone and/or polyurethane and/or epoxy resin. According to an embodiment variant of the invention, the interior of the tube may be filled completely with the polymer. Further, according to an alternative embodiment variant of the invention, the interior of the tube may be filled with the polymer in the region of the two tube ends, for example from the tube end up to 0.5 meters beyond a tube sheet. “Completely” may be understood to mean that the complete interior of the tube from one tube end to the other is filled with the polymer. In other words, no hollow spaces or empty regions are to remain inside the tube. “In the region of the tube ends” may be understood to mean that the introduced polymer extends from the tube end into the tube, for example up to 0.5 meters beyond the tube sheet, at both ends. In other words, a hollow space or empty region remains between the two filled regions. The polymer may be introduced using one or more lines, wherein a line is inserted into the tube through an opened tube end or a respective line is inserted through each respective opened tube end of a tube. Said line may be, for example, a hose or a flexible tube. To deliver the line or lines to the tube end or tube ends, they may be delivered to the steam generator or heat exchanger via the manholes or the loop lines. Such lines should have a maximum possible inner diameter to obtain a minimum frictional resistance of the polymer, which still has a low viscosity at that time, while being injected through the lines. The polymer is introduced in particular using pressure, said pressure preferably being generated by a pressure unit connected to the polymer blender. The pressure applied by said unit may range between 1 bar of excess pressure and 150 bars of excess pressure. This depends on the conditions, such as the diameter and/or the length of the tube and the line. According to an embodiment variant, the tubes are U-shaped tubes both ends of which end in a tube sheet, wherein a line is inserted through one of the opened tube ends and is then led to the turning point of the U-shaped tube, and wherein the polymer is then injected into the tube through the line, the line being retracted from the tube while injecting the polymer until the interior of the corresponding half of the tube is filled with polymer. According to an alternative embodiment variant, the tubes are U-shaped tubes both ends of which end in a tube sheet, wherein a line is inserted through one of the opened tube ends and is then led into the tube as far as about 0.5 meters beyond the tube sheet, and wherein the polymer is then injected into the tube through the line, the line being retracted from the tube while injecting the polymer until the corresponding portion of the tube is filled with polymer. In both embodiment variants, the second half or the second portion of the tube may be filled with polymer through the second open tube end in a like manner simultaneously with or subsequently to the injection of the polymer into said corresponding half or into said corresponding portion of the U-shaped tube. According to a modification of the invention, all tubes which are not sealed with plugs may be decontaminated, in particular through mechanical or chemical cleaning processes, for example through abrasive processes such as blasting processes, or through scavenging processes using solvents, prior to opening the sealed tubes. The openings may be created in the plugs by drilling, in particular using a two-stage drilling process, in order to avoid loose pieces. The opening may also be created by milling or eroding or other suitable processes. The openings may have a minimum diameter of, for example, 5 mm. The maximum diameter preferably corresponds roughly to the inner diameter of the tube, i.e. the plug is removed completely. The tubes may have inner diameters of about 10 to 20 mm. The detaching of the tubes provided with the polymer preferably also involves detaching the open tubes which are not provided with plugs and subsequently sorting out the tubes provided with polymer. According to a preferred and expedient modification of the invention, the tubes provided with polymer and/or the open tubes not provided with plugs are detached directly at or near a tube sheet or at the level of a tube sheet, in particular by sawing, said detaching being performed along a provided separation line which is preferably orthogonal to the vertically extending tubes. As an alternative, it is also possible to detach the tubes in a lying position. The separation line may, however, also be provided so as to extend through a tube sheet. The tubes completely filled with polymer are preferably segmented into multiple pieces, preferably after detachment, said segmenting being performed through cutting and/or sawing and/or thermal separation processes. Such segmenting facilitates the further processing, i.e. the transport of the tubes, which have a considerable length of up to 20 meters in the non-segmented state. The detached and sorted tubes provided with the polymer may be treated and/or disposed of as radioactive waste. Additionally or alternatively, the open tubes not provided with plugs may be treated and/or disposed of as less radioactive waste or non-radioactive waste after dismantling. The detached and sorted tubes provided with the polymer and the open tubes not provided with plugs may be assigned to different waste categories and disposed of separately. The invention will be explained in more detail below, also with respect to further features and advantages, by the description of embodiments and by reference to the accompanying drawing. FIG. 1 shows a simplified schematic representation of a steam generator 10 with which the method according to the invention for dismantling a steam generator 10 can be carried out. For reasons of clarity, the steam generator is shown to contain merely one primary circuit tube 11, which is shown enlarged. Normally, however, a steam generator will comprise a plurality of tubes 11, for example several thousands of such tubes 11. The method according to the invention initially involves opening one or both ends 12 of each sealed tube 11 by creating an opening 14 in the respective plug 13 or by removing the respective plug 13. FIG. 1 shows a tube 11 both ends 12 of which have been opened, the right end 12 by creating an opening 14 in the plug 13, and the left end 12 by removing the plug 13. The openings 14 in the plugs 13 are preferably created by drilling, in particular using a two-stage drilling process, in order to avoid loose pieces. However, milling or eroding processes are also possible instead of drilling. Prior to opening the sealed tubes 11, all tubes 11 which are not provided with plugs 13 are preferably decontaminated through mechanical or chemical cleaning processes, for example through abrasive processes such as blasting processes, or through scavenging processes using solvents. After opening one or both ends 12 of each sealed tube 11, a viscous polymer 24 which will cure inside the tube 11 is introduced into the initially sealed and now opened tube or tubes 11. The polymer 24 fills the tube 11 across the full tube cross-section at least in the region of the tube ends 12 and immobilizes contaminations in the filled portion inside the tube 11. The polymer used is a polymer 24 which performs crosslinking through polyaddition and consists of or comprises, for example, silicone and/or polyurethane and/or epoxy resin. Two variants for introducing the polymer will now be explained: According to the first variant, the interior 16 of the tube is filled completely with the polymer 24. This is done by introducing the polymer 24 using a line 15 configured as a hose, wherein said hose 15 is inserted through an opened tube end 12. To deliver the hose 15 to the tube end 12, it may be delivered to the steam generator 10 via the manhole 20 and/or the loop lines 21. The polymer 24 is introduced in particular using pressure, said pressure being generated by a pressure unit 23 connected to the polymer blender 22. The tubes 11 of the steam generator 10 are U-shaped tubes 11 both ends 12 of which end in a tube sheet 17. The hose 15 is inserted through one of the opened tube ends 12, in FIG. 1 the right tube end 12, and is then led to the turning point 18 of the U-shaped tube 11. The polymer 24 is then injected into the tube 11 through the hose 15, the hose 15 being retracted from the tube 11 while injecting the polymer 24 until the interior 16 of the corresponding half of the tube 11 is filled with polymer 24. FIG. 1 shows the beginning of the injection process. A part of the tube 11 has already been provided with polymer, and the hose 15 has already been retracted from the tube 11 to some extent. Simultaneously with or subsequently to, in FIG. 1 subsequently to, the injection of the polymer 24 into the corresponding half of the U-shaped tube, the second half of the tube 11 is filled with polymer 24 through the second opened tube end 12 in a like manner. According to the second variant, which is not shown in FIG. 1, the interior 16 of the tube is filled with the polymer 24 in the region of the two tube ends 12, for example over a length of about 0.5 meters, measured from the upper end of the tube sheet. This is done by introducing polymer 24 using two hoses 15, wherein a respective hose 15 is inserted into a tube 11 through each respective opened tube end 12 of said tube 11. The tubes 11 are U-shaped tubes 11 both ends 12 of which end in a tube sheet 17, wherein a hose 15 is inserted into the tube 11 through one of the opened tube ends 12 and is then led into the tube 11 as far as about 0.5 meters, measured from the upper end of the tube sheet. The polymer 24 is then injected into the tube 11 through the hose 15, the hose 15 being retracted from the tube 11 while injecting the polymer 24 until the corresponding portion of the tube 11 is filled with polymer 24. Simultaneously with or subsequently to the injection of the polymer 24 into the corresponding portion of the U-shaped tube 11, the second portion of the tube 11 is filled with polymer 24 through the second opened tube end 12 in a like manner. Once the polymer 24 has cured, the tubes 11 provided with polymer 24 are detached. At this time, the detached tubes 11 are sealed by the cured polymer 24. The detaching of the tubes 11 provided with the polymer 24 preferably also involves detaching the open tubes 11 which are not provided with plugs 13. The tubes 11 provided with polymer 24 as well as the open tubes 11 not provided with plugs 13 are detached by sawing directly at or near the tube sheet 17, said detaching being performed along a provided separation line A which is orthogonal to the vertically extending tubes 11. As an alternative, the separation line may, however, also be provided so as to extend through the tube sheet (not shown). The detached tubes 11 provided with the polymer 24 are then sorted out. After detachment, the tubes 11 completely filled with polymer 24 are segmented into multiple pieces, said segmenting being performed by sawing or other separation processes. The detached and sorted tubes 11 provided with the polymer 24 are treated and disposed of as radioactive waste. The open tubes 11 not provided with plugs 13 are treated and disposed of as less radioactive waste or non-radioactive waste after dismantling. 10 steam generator 11 tube 12 tube end 13 plug 14 opening in plug 15 hose 16 interior 17 tube sheet 18 turning point 19 hand hole 20 manhole 21 loop line 22 polymer blender 23 pressure unit 24 polymer A separation line
	abstract	A tool for cleaning a pool, particularly in a radioactive environment. The tool comprises a liquid filtering device, a pump, and a tank. The tank comprises an inlet for liquid from the pool. The tank at least partly houses the filtering device and the pump. The filtering device is arranged between the inlet and the pump so as to fluidically connect said inlet and pump.
	abstract	The disclosure relates to an optical module with first and second components, a supporting structure and an anticollision device. The first component is supported by the supporting structure and is arranged adjacent to and at a distance from the second component to form a gap. The supporting structure defines a path of relative movement, on which the first and second components move in relation to one another under the influence of a disturbance, a collision between collision regions of the first and second components occurring if the anticollision device is inactive. The anticollision device includes a first anticollision unit on the first component, which produces a first field, and a second anticollision unit on the second component, which is assigned to the first anticollision unit and produces a second field.
	abstract	An in-situ testing apparatus for testing the integrity of rib plugs used to seal faulty reactor boiler tubes consists of a cup-shaped member with a groove on the open end, a tapped hole for attaching a hydraulic hose of known pressure, and a hole through the top of the member. A seal is installed in the groove on the open end of the cup to seal to the primary face of a tubesheet around the tested rib plug. A threaded mandrel goes through the hole in the top of the cup-shaped member and engages the expander member of the rib plug. The threading action of the mandrel into the expander draws the seal against the tubesheet to seal the testing apparatus and allows the rib plug to be in-situ pressure tested.
	claims	1. An electronic device comprising: a sensor outputting signals indicating environmental conditions experienced by said electronic device; a non-volatile memory storing ones of said signals that exceed a limit; and an audible output device outputting signals stored in said non-volatile memory, thereby providing feedback of said environmental conditions experienced by said electronic device that exceed said limit; wherein said sensor and said non-volatile memory operate when said electronic device is off and, when said electronic device is turned on, said non-volatile memory provides said history through said output device, and wherein, when said environmental conditions exceed an alert threshold, said audible output device immediately sounds an alert, both when said device is off and when said device is on. 2. The electronic device in claim 1 , wherein said output device comprises a display device. claim 1 3. The electronic device in claim 1 , wherein said signals indicate when said environmental conditions occurred and a magnitude of said environmental conditions. claim 1 4. The electronic device in claim 1 , wherein said non-volatile memory initiates a diagnostic program after said electronic device experiences an environmental condition that exceeds said limit, wherein said diagnostic program evaluates whether said environmental condition has damaged said electronic device. claim 1 5. The electronic device in claim 1 , further including a connection to a network, said signals stored in said non-volatile memory being transmitted to said network. claim 1 6. A portable computing device comprising: an acceleration sensing unit outputting signals indicating accelerations experienced by said portable computing device; a non-volatile memory storing ones of said signals that exceed a limit; and an audible output device outputting signals stored in said non-volatile memory, thereby providing immediate feedback of said accelerations experienced by said portable computing device that exceed said limit, both when said device is on and when said device is off. 7. The portable computing device in claim 6 , wherein said output device comprises a display device. claim 6 8. The portable computing device in claim 6 , further comprising a direct access storage device wherein said signals indicate when said accelerations occurred, a magnitude of said accelerations, and a position of a slider of said direct access storage device when said accelerations occurred. claim 6 9. The portable computing device in claim 8 , wherein said non-volatile memory initiates a diagnostic program after said computer experiences acceleration that exceeds said limit, wherein said diagnostic program evaluates whether said acceleration has damaged said direct access storage device. claim 8 10. The portable computing device in claim 6 , further including a connection to a network, said signals stored in said non-volatile memory being transmitted to said network. claim 6 11. The portable computing device in claim 6 , wherein said acceleration sensing unit and said non-volatile memory operate when said portable computing device is off and, when said portable computing device is turned on, said non-volatile memory displays said history on said output device. claim 6 12. A method for protecting an electronic device comprising: detecting environmental conditions experienced by said electronic device; generating signals indicating said environmental conditions experienced by said electronic device; storing ones of said signals that exceed a limit; outputting signals stored in said non-volatile memory, thereby providing feedback of said environmental conditions experienced by said electronic device that exceed said limit; and performing said detecting, said generating, and said storing when said electronic device is off and, when said electronic device is turned on, performing said outputting, wherein, when said environmental conditions exceed an alert threshold above said limit, said device immediately sounds an alert, both when said device is off and when said device is on. 13. The method in claim 12 , wherein said outputting comprises generating a display. claim 12 14. The method in claim 12 , wherein said signals indicate when said environmental conditions occurred and a magnitude of said environmental conditions. claim 12 15. The method in claim 12 , further comprising initiating a diagnostic program after said electronic device experiences an environmental condition that exceeds said limit, wherein said diagnostic program evaluates whether said environmental condition has damaged said electronic device. claim 12 16. The method in claim 12 , further comprising transmitting said signals in said non-volatile memory to an external network. claim 12 17. An electronic device comprising: a sensor outputting signals indicating environmental conditions experienced by said electronic device; a non-volatile memory storing ones of said signals that exceed a limit; an output device outputting signals stored in said non-volatile memory, thereby providing a history of said environmental conditions experienced by said electronic device that exceed said limit; and a peak detection unit storing a largest one of said signals said non-volatile memory periodically sampling said peak detection unit, wherein said sensor and said non-volatile memory operate when said electronic device is off and, when said electronic device is turned on, said non-volatile memory provides said history through said output device. 18. A portable computing device comprising: an acceleration sensing unit outputting signals indicating accelerations experienced by said portable computing device; a non-volatile memory storing ones of said signals that exceed a limit; an audible output device outputting signals stored in said non-volatile memory, thereby providing a history of said accelerations experienced by said portable computing device that exceed said limit; and a peak detection unit storing a largest one of said signals, said non-volatile memory periodically said peak detection unit. 19. A method for protecting an electronic device comprising: detecting environmental conditions experienced by said electronic device; generating signals indicating said environmental conditions experienced by said electronic device; storing ones of said signals that exceed a limit; outputting signals stored in said non-volatile memory, thereby providing a history of said environmental conditions experienced by said electronic device that exceed said limit; performing said detecting, said generating, and said storing when said electronic device is off and, when said electronic device is turned on, performing said outputting; periodically storing a largest signal of said signals; and periodically sampling and resetting said largest signal.
060977795	claims	1. A reactor pressure vessel of a nuclear reactor comprising: a top guide having a plurality of top guide beams and top guide beam segments, said top guide beams defining a plurality of cell openings, said top guide beam segments extending from said top guide beams to define a plurality of group openings within each of said cell openings, each said group opening sized to receive a plurality of fuel bundles; a core plate spaced from said top guide; and a plurality of fuel bundles and a plurality of large control rods arranged in an F-lattice arrangement, each said large control rod comprising four fuel bundle receiving channels, each said fuel bundle receiving channel sized to receive a same number of fuel bundles as each of said group openings, said large control rod movable between said core plate and said top guide. a plurality of fuel bundles; a plurality of large control rods arranged in an F-lattice arrangement, each said large control rod comprising four fuel bundle receiving channels, at least one of said channels sized to receive at least two of said fuel bundles therein; and a top guide having a plurality of group openings, each said group opening sized to receive a same number of fuel bundles as one of said fuel bundle receiving channels. a top guide having a plurality of top guide openings; a core plate spaced from said top guide; and a plurality of fuel bundles and a plurality of large control rods arranged in an F-lattice arrangement, each said large control rod comprising four fuel bundle receiving channels, each said fuel bundle receiving channel sized to receive a plurality of fuel bundles, each said large control rod movable between said core plate and said top guide. 2. A reactor pressure vessel in accordance with claim 1 wherein each said cell opening is sized to receive sixteen fuel bundles and wherein each group opening is sized to receive four fuel bundles. 3. A reactor pressure vessel in accordance with claim 1 wherein said plurality of fuel bundles extend between said top guide and said core plate, at least one of said fuel bundles positioned in one of said group openings. 4. A reactor pressure vessel in accordance with claim 3 further comprising a spring and guard assembly coupled to at least one of said fuel bundles. 5. A reactor pressure vessel in accordance with claim 3 further comprising a channel spacer coupled to at least one of said fuel bundles. 6. A reactor pressure vessel comprising: 7. A reactor pressure vessel in accordance with claim 6 wherein said group openings are sized to receive four fuel bundles. 8. A reactor pressure vessel in accordance with claim 6 wherein said top guide comprises a plurality of beams defining a plurality of cell openings, each said cell opening sized to receive a plurality of fuel bundles, and a plurality of beam segments, said beam segments extending from said top guide beams to define a plurality of group openings within each of said cell openings. 9. A reactor pressure vessel of a nuclear reactor comprising: 10. A reactor pressure vessel in accordance with claim 9 wherein each said large control rod comprises a central portion having four blades extending therefrom, said blades defining four fuel bundle receiving channels. 11. A reactor pressure vessel in accordance with claim 9 wherein each said fuel bundle receiving channel is sized to receive four fuel bundles. 12. A reactor pressure vessel in accordance with claim 9 wherein said top guide comprises a plurality of top guide beams, and wherein each said large control rod is configured to be inserted in at least one of said top guide beams. 13. A reactor pressure vessel in accordance with claim 12 wherein each said large control rod comprises a central portion having a plurality of blades extending therefrom, said top guide further comprises a plurality of top guide beams, and wherein at least one of said top guide beams includes at least one recess sized to receive a portion of one of said blades. 14. A reactor pressure vessel in accordance with claim 9 wherein said plurality of fuel bundles extend between said top guide and said core plate, at least one of said fuel bundles positioned in one of said fuel bundle receiving channels. 15. A reactor pressure vessel in accordance with claim 14 further comprising a spring and guard assembly coupled to at least one of said fuel bundles. 16. A reactor pressure vessel in accordance with claim 14 further comprising a channel spacer coupled to at least one of said fuel bundles.
042108179	abstract	Film changers used in biplane radiography are provided with shields having radiolucent and radiopaque sections which are alternately disposed in front of the x-ray film presented by the film changers for exposure. Operation of the two shields is synchronized to dispose the radiopaque portion of one shield in front of one changer when the radiolucent portion of the other shield is disposed in front of the other changer such that scattered radiation cannot reach film in the one changer and fog it when an image is being recorded by the other changer. In one disclosed embodiment of the invention, the shield is a flexible endless belt with alternating radiopaque and radiolucent sections mounted for rotation in a loop around the film changer. In a second disclosed embodiment of the invention, planar discs having alternating radiopaque and radiolucent sectors are rotated in front of the film changers. In yet another embodiment of the invention, planar members, each having one radiopaque and one radiolucent section, are mounted for reciprocal movement in front of the film changers.
042960746	abstract	A method of decladding an assembly comprising an element selected from the group consisting of uranium, thorium and mixtures thereof, clad in stainless steel, zirconium, or an alloy consisting essentially of zirconium and containing minor amounts of nickel, chromium, tin, iron or combinations thereof. In a first step the cladding is scored or perforated to expose the selected element. Thereafter, the assembly is exposed to a hydrogen atmosphere at an elevated temperature for a time sufficient for the hydrogen and selected element to react and form a hydride. The temperature then is further increased to decompose the hydride back to gaseous hydrogen and the selected element. The hydriding-dehydriding preferably are repeated at least two additional times to ensure complete release of any volatile gases present. The formation of the hydride which has substantially greater volume than the selected element ruptures the cladding assembly and the subsequent dehydriding leaves the selected element in a friable granular form whereby it is readily separable from the cladding material by conventional mechanical means such as sieving or the like.
	description	This application priority from, and is a 35 U.S.C. §111(a) continuation of, co-pending PCT international application serial number PCT/US2006/000113, filed on Jan. 3, 2006, incorporated herein by reference in its entirety, which claims priority from U.S. provisional application Ser. No. 60/641,302, filed on Jan. 3, 2005, incorporated herein by reference in its entirety. This invention was made with Government support under Grant No. DMR 0309886, awarded by the National Science Foundation and Grant Nos. N00014-03-1-07 and N00014-04-1-07, awarded by the Department of Defense. The Government has certain rights in this invention. A portion of the material in this patent document is subject to copyright protection under the copyright laws of the United States and of other countries. The owner of the copyright rights has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the United States Patent and Trademark Office publicly available file or records, but otherwise reserves all copyright rights whatsoever. The copyright owner does not hereby waive any of its rights to have this patent document maintained in secrecy, including without limitation its rights pursuant to 37 C.F.R. §1.14. 1. Field of the Invention This invention pertains generally to fusion research, and more particularly to the use of a pyroelectric crystal in a deuterated atmosphere to generate fusion under desktop conditions. 2. Description of Related Art While progress in fusion research continues with magnetic and inertial confinement, alternative approaches—such as Coulomb explosions of deuterium clusters and ultrafast laser-plasma interactions—also provide insight into basic processes and technological applications. However, attempts to produce fusion in a room temperature solid-state setting, including “cold” fusion and “bubble” fusion, have met with deep skepticism. Gently heating a pyroelectric crystal in a deuterated atmosphere can generate fusion under desktop conditions. The electrostatic field of the crystal is used to generate and accelerate a deuteron beam (>100 keV and >4 nA), which, upon striking a deuterated target, produces a neutron flux over 400 times the background level. The presence of neutrons within the target is confirmed by pulse shape analysis and proton recoil spectroscopy. The applicable reaction is D+D→3He (820 keV)+n (2.45 MeV). An aspect of the invention is a method, comprising positioning a probe tip adjacent a crystal, and using the probe tip to produce field ionization of a neutron source; wherein the ionization results in production of neutron flux; and wherein the crystal is a pyroelectric or piezoelectric crystal. One embodiment further comprises heating the crystal, wherein the crystal is a pyroelectric crystal. In another embodiment, the pyroelectric crystal comprises lithium tantalite. Another embodiment further comprises providing a deuterated or tritiated target in a position of a trajectory defined by the probe tip. In another embodiment, the target comprises erbium dideuteride. Another embodiment further comprises providing a target in a position of a trajectory defined by the probe tip, wherein the target comprises a neutron source. In other embodiments, the crystal is ruptured, compressed, or exploded; the crystal comprises a matrix or mosaic of crystals; the crystal comprises a laminated crystal; or the probe tip is one of a plurality of tips adjacent the crystal. Another aspect of the invention is a method, comprising locating a probe tip adjacent a pyroelectric crystal, heating the pyroelectric crystal in an environment containing a gaseous source of neutrons, wherein heating the pyroelectric crystal produces a beam about the probe tip, and positioning a target in a trajectory of the beam, wherein contact between the beam and the target produces a neutron flux. In other embodiments, the pyroelectric crystal comprises lithium tantalite, or the target comprises erbium dideuteride. A still further aspect of the invention is an apparatus, comprising: a chamber, means for securing a pyroelectric crystal in the chamber, means for positioning a probe tip adjacent the pyroelectric crystal; and means for positioning a target comprising a neutron source. One embodiment further comprises means for heating said pyroelectric crystal. In other embodiments, the chamber is configured to contain an atmosphere comprising a neutron source; the pyroelectric crystal comprises lithium tantalite; or the target comprises erbium dideuteride. Further aspects of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing preferred embodiments of the invention without placing limitations thereon. Referring more specifically to the drawings, for illustrative purposes the present invention is embodied in the apparatus generally shown in FIG. 1A through FIG. 4C. It will be appreciated that the apparatus may vary as to configuration and as to details of the parts, and that the method may vary as to the specific steps and sequence, without departing from the basic concepts as disclosed herein. Because its spontaneous polarization is a function of temperature, heating or cooling a pyroelectric crystal in vacuum causes bound charge to accumulate on faces normal to the polarization. A modest change in temperature can lead to a surprisingly large electrostatic field. For example, heating a lithium tantalate crystal from 240 K to 265 K decreases its spontaneous polarization by 0.0037 Cm−2. In the absence of spurious discharges, introducing this magnitude of surface charge density into the particular geometry of our experiment (FIG. 1A, 1B) gives a potential of 100 kV. Attempts to harness this potential have focused on electron acceleration and the accompanying bremsstrahlung radiation, but using the crystal to produce and accelerate ions has been studied much less. Seeking to drive the D-D fusion reaction, we set out to develop a method of reliably producing an ion beam of sufficient energy (>80 keV) and current (>1 nA). We demonstrate such a method using a tungsten tip to generate the high field (>25 V nm−1) necessary for gas phase field ionization of deuterium. The vacuum chamber setup is shown in FIG. 1A. A cylindrical z-cut LiTaO3 crystal 12 (diameter, 3.0 cm; height, 1.0 cm) was mounted inside a chamber 14 with negative axis facing outward onto a hollow copper block 16. A heater 18 is located adjacent the crystal 12. On the exposed crystal face, we attached a copper disc 20 (diameter, 2.5 cm; height, 0.5 mm), allowing charge to flow to a tungsten probe 22 (shank diameter, 80 μm; tip radius, 100 nm; length, 2.3 mm) (FIG. 1B). The probe geometry was chosen so that the tip field was approximately 25 V nm−1 when the crystal face was charged to 80 kV. D2 pressure was set using a leak valve and monitored with a D2 compensated Pirani gauge. The target 24 was a molybdenum disc coated with ErD2. FIG. 1A also shows calculated equipotentials and D+ trajectories 26 for a crystal charged to 100 kV; calculations were performed using finite-element methods. The grounded copper mesh 28 (85% open area, 19.8-mm wire) shields the Faraday cup 30. The cup 30 and target 24 are connected to a Keithley 6485 picoammeter and biased to +40 V to collect secondary electrons and help prevent avalanche discharges. FIG. 1B shows the same trajectories as in FIG. 1A, but near the tip 22. Using a shorter tip reduces the beam's angular spread. The neutron detector (not shown) consists of six liquid scintillator (BC-501A and NE213) cells (diameter, 127 mm; height, 137 mm), each optically coupled to a 127-mm Hamamatsu R1250 photomultiplier tube (PMT). One output of each PMT was fed into a logical OR trigger, while the other output was fed into two Acqiris DC270 8-bit (1 gigasample per second) 4-channel digitizers configured as a single 8-channel digitizer. For every trigger, a 650-ns waveform was digitized simultaneously on all channels and written to disk for later analysis. To better resolve the bremsstrahlung endpoint, a 2.5-cm aluminium filter was placed between the X-ray detector and the viewport. The vacuum chamber's thick stainless steel walls and lead sheet shielded the neutron detector from X-rays. A typical run is shown in FIG. 2A-2D. FIG. 2A shows the crystal temperature as a function of time. The heating rate was 12.4 K min−1, corresponding to a pyroelectric current of 22 nA and a heating power of 2 W. FIG. 2B shows X-rays detected, FIG. 2C shows Faraday cup current, and FIG. 2D shows neutrons detected, each as a function of time, for the same run. For the results shown in FIG. 2A-2D, the chamber's deuterium pressure was held at 0.7 Pa throughout the run. First, the crystal was cooled down to 240 K from room temperature by pouring liquid nitrogen into the cryogenic feedthrough. At time t=15 s, the heater was turned on. At t=100 s, X-ray hits due to free electrons striking the crystal were recorded. At t=150 s, the crystal had reached 80 kV and field ionization was rapidly turning on. At t=160 s and still not above 0° C., the neutron signal rose above background. Ions striking the mesh and the surrounding aperture created secondary electrons that accelerated back into the crystal, increasing the X-ray signal. At t=170 s, the exponential growth of the ion current had ceased, and the tip was operating in the strong field regime, in which neutral molecules approaching the tip ionize with unity probability. The neutron flux continued to increase along with crystal potential until t=220 s, when we shut off the heater. Then, the crystal lost charge through field ionization faster than the reduced pyroelectric current could replace it, resulting in a steadily decreasing crystal potential. At t=393s, the crystal spontaneously discharged by sparking, halting the effect. Pulse shape analysis and proton recoil spectroscopy of neutron detector data collected during the run are shown in FIG. 3A-3B. The energy scale, given in electron equivalent (e.e.) energy, was calibrated against Compton edges of a series of γ-ray sources and is proportional to anode charge. FIG. 3A shows the pulse shape discrimination (PSD) spectrum. The PSD variable “slow light/fast light” is the ratio of integrated light in the tail of the PMT signal generated by an event in the liquid scintillator, to the integrated light around the signal's peak. Electron recoils are in the lower branch, and proton recoils, having longer scintillation decay, are in the upper branch. The events enclosed within the upper region are compared against tabulated pulse shapes, rejecting unusual events such as PMT double pulsing. There were a total of 15,300 valid neutrons over the course of the 400-s run. From the distribution of events, we estimate that the number of electron events leaking into the proton branch is negligible compared to the 1% cosmic background. FIG. 3B shows the proton recoil spectrum. Valid neutron events are shown in histogram format. For comparison, we also show our detector's simulated responses to 1.45 MeV, 2.45 MeV and 3.45 MeV centre-of-mass boosted neutrons. The majority of background triggers, as collected in the first 100 s of the run, have an electron recoil shape (900 counts per second) and are due to cosmic muons and γ-rays, compared with relatively few triggers having a proton recoil shape (33 counts in the first 100 s). Correcting for our 18% 2.45-MeV neutron detection efficiency, the observed peak neutron flux was 800 neutrons per second. We may compare this observed peak neutron flux to the neutron flux expected from the ion beam striking the ErD2 target. At the time of peak neutron flux, the ion current was 4.2 nA and the accelerating potential, inferred from the bremsstrahlung endpoint, was 115 kV. Using tabulated stopping powers and fusion cross-sections, we calculate a neutron flux of 900 neutrons s−1. This is a slight overestimate, because part of the ion beam struck outside the target and there was an oxide layer on the target. In FIG. 4A-4C, neutron time-of-flight measurements are presented as further evidence for this fusion reaction, demonstrating the delayed coincidence between the outgoing α-particle and the neutron. In FIG. 4A, a deuteron 40 is shown striking a thin disk of deuterated plastic scintillator 24, where it fuses with another deuteron, producing an 820-keV 3He 42 and a 2.45-MeV neutron 44. The α-particle 42 promptly scintillates in the plastic 24, recorded by a photomultiplier tube 46 coupled to the glass UHV viewport 48 through a silicone optical pad 50. The neutron 44, on the other hand, leaves the vacuum chamber 14, and is shown detected via proton recoil in the liquid scintillator 52. FIG. 4B shows simultaneously captured PMT traces, demonstrating the α-particle-neutron coincidence. The plastic scintillator trace, shown in the upper panel, has a large α-particle hit at t=0 ns, whereas the smaller hits are incident deuterons that stopped in the plastic but did not fuse. The liquid scintillator trace, shown in the lower panel, has a proton hit at t=6 ns. FIG. 4C shows time-of-flight results. The distribution of neutron flight times is shown in the upper histogram. As the neutron emission and detection volumes are finite and relatively closely spaced, we observe a range of flight times. The Monte Carlo flight time distribution, including a constant term to account for background, is shown fitted. The peak in the distribution roughly corresponds with the 5.6 ns it takes a 2.45-MeV neutron moving with a velocity of 0.07c (where c is the speed of light) to travel 12 cm. The relative timing offset between the two PMTs was calibrated using back-to-back 511-keV γ-rays from a 22Na source, as shown in the lower histogram. Using deuterated plastic scintillator (BC-436) as both a deuterated target, and as a scintillation material, allowed us to pinpoint individual fusion events. The scintillator was mounted inside the chamber against a glass ultrahigh-vacuum (UHV) viewport, through which a Hamamatsu H1949-50 PMT was coupled via a silicone optical pad (FIG. 4B). The side of the scintillator facing the beam had a 50-nm layer of evaporated aluminium and was connected to the picoammeter. The aluminium prevented the target from charging up, allowed for a reliable beam current measurement, and helped screen out stray light originating from within the chamber. To minimize background hits, yet still collect valid coincidences, we used a reduced deuterium pressure and a reduced heating rate so that the ion current was around 10 pA. Running at this low level permitted prolonged runs. For example, the data shown in FIG. 4C were taken from a single heating cycle lasting over eight hours. The present invention is not limited to the foregoing example, but can be enhanced by varying the included components. For example, the response of a crystal is preferably optimized by controlling the size, purity, conductivity, dielectric coefficient, chemical composition, mounting, and roughness. A matrix or mosaic of crystals may also be used in place of a single crystal. In this embodiment, these crystals would be grouped into an array that optimizes the field or current. A geometry can be preferably chosen that maximizes the electric field, or other desirable parameter. Laminated crystals can be used. Finally, all forms of piezoelectric crystals are appropriate, creating embodiments that include crystals in which stress and strain, rather than temperature, can be used to create fields for fusion. The term “mounting” refers to the method used to attach the crystal to a heater, a cooler, or some other source of stimulus. The term also includes the technique used to fasten a tip or electrode to a crystal face. Examples include the use of conducting or non-conducting epoxy, vacuum glues, silver paint, or other mounting methods, such as clamping. An electrode is a surface that conditions the electric field generated by the crystal, and includes sheets, foils, or films of such materials as gold, aluminum, or tungsten. Other suitable metals can also be used. The tip, as disclosed encompasses a region which has a sharp or a rounded edge whose radius of curvature ranges from microns to about 10 nanometers. A tip is not limited to merely a solid material, but can be made from a liquid, including, but not limited to, a gallium coating on a metal. In addition, an array of tips can be used to improve the yield. Moreover, the overall environment, which includes, but is not limited to, the ambient temperature, humidity, and pressure, is variable as well. Finally, applications using deuterated or tritiated systems are possible. In such applications, deuterium or tritium gas is introduced into the region of the crystal, or the hydrogen in the crystal is replaced with deuterium or tritium. Deuterium or tritium can also be adsorbed onto the crystal surface or loaded into the crystal. Gases and targets incorporating other elements that undergo nuclear reactions are also included in the present invention. The value of any of these variables is preferably chosen to minimize or prevent unwanted internal and surface discharges (e.g., sparking). Alternatively, the crystal, if ruptured, compressed, or exploded, can also produce a fusion reaction. Ultimately, the choice design parameters of the entire system takes all these variables into account. The parameters include, but are not limited to, the strength and spatial dependence of the electric field, the localization of the electric field, the current of ions and electrons emitted, and the energy and quantity of x-rays generated by the crystal with various mountings, tips, and stimuli. Although the reported fusion is not useful in the power-producing sense, we anticipate that the system will find application as a simple palm-sized neutron generator. We note that small (about centimetre-sized) pyroelectric crystals can produce ion beams of sufficient energy and current to drive nuclear fusion. We anticipate increasing the field ionization current by using a larger tip, or a tip array, and by operating at cryogenic temperatures. With these enhancements, and in addition using a tritiated target, we believe that the reported signal could be scaled beyond 106 neutrons s−1. Pyroelectric crystals may also have applications in electrostatic fusion devices, such as the Farnsworth fusor, and as microthrusters in miniature spacecraft. Applications also include use as a compact focused ion generator for the front end of a neutron camera in associated particle imaging (API). Although the description above contains many details, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Therefore, it will be appreciated that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” All structural, chemical, and functional equivalents to the elements of the above-described preferred embodiment that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112, sixth paragraph, unless the element is expressly recited using the phrase “means for.”
	summary
055464351	description	DESCRIPTION OF THE PREFERRED EMBODIMENT In the FIGURE, 1 designates a loading machine for fuel assemblies for a pressurized-water reactor, 2 the reactor hall floor along which the loading machine is movable, 3 the reactor vessel, 4 the reactor core, 5 a pool located above the reactor vessel with reactor water, and 6 the reactor water in the reactor vessel and in the pool. The loading machine is provided with a lifting mast 7 of preferably telescopic design. The mast 7 is cylindrical and has an internal chamber wide enough to house a fuel assembly. A gripping device 8 provided at the end of a wire 8' provided inside the mast 7 is adapted to grip a lifting handle on a fuel assembly 10 which in the illustrated case is being lifted out of the reactor core and drawn well into the mast by a motor 11. The mast with the fuel assembly 9 is lifted upp into the pool 5 so that the fuel assembly comes near the upper water level, but so that the fuel assembly is surrounded by water 12. The mast counteracts that water which has passed the fuel assembly spreads to the area ouside the mast, which would mean that leaked-out fission products would be lost for the analysis. A hose 14 or other conduit extends from the upper part of the mast 7 to a little distance below the water level inside the mast but above the fuel assembly 9. The conduit 14 includes a pump 13 by means of which the water is sucked from the water 12 inside the mast 7, which is open in its lower end. The reactor water is caused to stream inside the mast 7 from below as marked by arrows and to flow around and through the fuel assembly 9 by the action of the pump 13. The fuel assembly is all the time located below the water level. Water is pumped by the pump 13 to a gas separator 22 in which gases present in the water are released therefrom by lowering the pressure and therewith decreasing the solubility of the gases in water. The gas separator 22 includes at least one gas space 23 having a small volume and one water reservoir 24. The gas space 23 and the water reservoir 24 are separated by means of a waterseal 25. In order to achieve a more effective release of the gases present in the samples in accordance with the present invention, the water is finely-divided, or atomized, with the aid of spray devices 26 mounted in the gas space 23, in conjunction with passing the water to the gas separator 22. The gases released from the water, these gases possibly containing gaseous fission products, are mixed with a working gas present in the gas separator 22 and are pumped through a gas circuit 27 to a measuring chamber 28 in which the gases are analyzed for the occurrence of gaseous fission products with the aid of a detector which functions to detect radioactivity in gases. The detection result could be presented on a display 35. The degasified water is passed to the water reservoir 24 in which any radioactivity in the water could be detected separately (not shown). Alternatively, water samples can be sent to a separate laboratory for analysis. Then the degasified water is conducted back to the pool 5 through a hose 36. In the case of low activity in the water samples, the enrichment of gaseous fission products in the detection system necessary for detection purposes is achieved by pumping large quantities of water sample through the gas separator 22 in which the water is degasified. The gas circuit 27 includes a pump 31 which functions to pump any gas present in the circuit 27 and the gas space 23 around said gas circuit 27 and the gas space 23, therewith enriching any gaseous fission products present. To ensure that dry gas is delivered to the measuring chamber 28 for detecting radioactivity in gases, the gas circuit 27 conveniently includes a moisture separator 32, a gas dryer 33 and an iodine trap 34 between the gas space 23 and the measuring chamber 28. While the invention has been described with reference to a specific embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the true spirit and scope of the invention. In addition, modifications may be made without departing from the essential teachings of the invention as expressed in the accompanying claims.
	claims	1. A method of replacing a subassembly within a core spray nozzle of a nuclear reactor, the subassembly including a T-box and a thermal sleeve, and the core spray nozzle including a safe end with a converging inner surface, the method comprising:removing the T-box and the thermal sleeve;providing a second T-box and a second thermal sleeve, the second T-box having a first end adjacent the second thermal sleeve;assembling a cruciform subassembly in the safe end of the core spray nozzle, the cruciform subassembly configured to create a seal against an inner circumference of the converging inner surface; andadjusting a clamp attached to a second or third end of the second T-box to seal the cruciform subassembly against the converging inner surface of the safe end of the core spray nozzle. 2. The method of claim 1, whereinassembling the cruciform subassembly in the safe end of the core spray nozzle includes joining together a primary cruciform wedge and a secondary cruciform wedge. 3. The method of claim 1, further comprising:inserting a draw bolt through the cruciform subassembly. 4. The method of claim 1, further comprising:providing a spider adjacent to the cruciform subassembly; andinserting a draw bolt through the spider and the cruciform subassembly. 5. The method of claim 4,wherein the spider directly contacts the cruciform subassembly. 6. The method of claim 2, wherein the primary cruciform wedge includesa first support member extending between a first web member and a second web member, anda second support member extending between a third web member and a fourth web member. 7. The method of claim 6, wherein the secondary cruciform wedge includesa third support member extending between a fifth web member and a sixth web member, anda fourth support member extending between a seventh web member and an eighth web member. 8. The method of claim 7, wherein joining together the primary cruciform wedge and the secondary cruciform wedge includes joining the primary and secondary cruciform members such that the first, second, third, fourth, fifth, sixth, seventh, and eighth webs form an “X” shaped configuration and the first, second, third, and fourth support members form a substantially contiguous support member. 9. The method of claim 8, wherein the first, second, third, and fourth support members are tapered to engage an inside surface of the nozzle safe end. 10. The method of claim 8, wherein the inner circumference of the converging inner surface is defined by an interface between the first, second, third, and fourth support members of the primary cruciform wedge and the secondary cruciform wedge and the converging inner surface. 11. The method of claim 4, wherein the spider is configured to connect to the cruciform subassembly. 12. The method of claim 11, wherein the cruciform subassembly includes a side facing the spider and the spider includes a side facing the cruciform subassembly and the side of the cruciform subassembly facing the spider includes one of a tongue and a groove and the side of the spider facing the cruciform subassembly includes the other of the tongue and the groove. 13. The method of claim 12, further comprising:connecting the spider and the cruciform subassembly via the tongue and groove. 14. A method of replacing a subassembly within a core spray nozzle of a nuclear reactor, the subassembly including a T-box and a thermal sleeve, and the core spray nozzle including a safe end with a converging inner surface, the method comprising:removing the T-box and the thermal sleeve;providing a second T-box and a second thermal sleeve, the second T-box having a first end adjacent the second thermal sleeve;inserting replacement hardware configured to create a seal against an inner circumference of the converging inner surface; andsealing the replacement hardware against the converging inner surface of the safe end of the core spray nozzle by adjusting a clamp attached to a second or third end of the second T-box. 15. The method of claim 14, wherein inserting replacement hardware includes inserting a primary cruciform wedge into the safe end of the core spray nozzle and inserting a secondary cruciform wedge into the safe end of the core spray nozzle. 16. The method of claim 15, further comprising:inserting a draw bolt through the primary cruciform wedge and the secondary cruciform wedge. 17. The method of claim 14, further comprising:providing a spider adjacent to the replacement hardware;inserting a draw bolt through the replacement hardware, and the spider to attach the spider to the replacement hardware. 18. The method of claim 17, whereinthe spider directly contacts the replacement hardware. 19. The method of claim 14 further comprising:providing a spider near the replacement hardware;inserting a drawbolt through the spider and replacement hardware; andtensioning the drawbolt to press the spider against the replacement hardware such that the spider does not directly contact an inside surface of the nozzle safe end.
	summary
	claims	1. A feed-through element for harsh environments, comprising:a support body with an access opening;at least one functional element is arranged in the access opening; andan electrically insulating fixing material securing the at least one functional element in the access opening and electrically insulating the at least one functional element from the support body,wherein the electrically insulating fixing material contains a glass or a glass ceramics with a volume resistivity of greater than 1.0×1010 Ωcm at the temperature of 350° C. and said glass or glass ceramics comprises in mole % on oxide basis:SiO2 25-55,B2O30.1-15,Al2O3 0-15,MO 20-50, andM2O 0-<2,wherein MO is selected from the group consisting of MgO, CaO, SrO, BaO, and any combinations thereof, andwherein M2O is selected from the group consisting of Li2O, Na2O, K2O, and any combinations thereof. 2. The feed-through element according to claim 1, wherein the electrically insulating fixing material has an electrical insulation resistivity of at least 500 MΩ at an operation temperature of 260° C. 3. The feed-through element according to claim 1, wherein the at least one functional element is selected from the group consisting of an electrical conductor, a waveguide, a cooling-fluid line, a housing of a thermo element, and a hollow element which carries further functional elements. 4. The feed-through element according to claim 1, wherein the electrically insulating fixing material fixes the at least one functional element within the access opening to withstand pressures in excess of 42000 psi at an operational temperature of 260° C. 5. The feed-through element according to claim 1, wherein the electrically insulating fixing material hermetically seals the access opening. 6. The feed-through element according to claim 1, wherein the electrically insulating fixing material has a CTE that matches a CTE of the support body. 7. The feed-through element according to claim 1, wherein the electrically insulating fixing material has a CTE that is smaller than a CTE of the support body, whereby at least at room temperature the support body exerts an additional holding pressure to the electrically insulating fixing material. 8. The feed-through element according to claim 1, wherein the support body is made from a ceramic selected from the group consisting of Al2O3 ceramics, stabilized ZrO2 ceramics, Mica, and any combinations thereof. 9. The feed-through element according to claim 1, wherein the support body is made from a metal selected from the group consisting of stainless steel SAE 304 SS, stainless steel SAE 316 SS, Inconel, and alloys or combinations thereof. 10. The feed-through element according to claim 1, wherein the functional element comprises a metal material selected from the group consisting of Beryllium Copper, Nickel-Iron Alloy, Kovar, Inconel and alloys or combinations thereof. 11. The feed-through element according to claim 1, wherein the functional element consists essentially of Beryllium Copper and the support body consists essentially of stainless steel SAE 304 SS or stainless steel SAE 316 SS. 12. The feed-through element according to claim 1, wherein the functional element consists essentially of Nickel-Iron Alloy and the support body consists essentially of 304 SS or Inconel. 13. The feed-through element according to claim 1, further comprising a connector element consisting essentially of Kovar, wherein the support body consists essentially of Inconel. 14. The feed-through element according to claim 1, further comprising a connector element consisting essentially of Inconel, wherein the support body consists essentially of Inconel. 15. The feed-through element according to claim 1, wherein the glass or glass ceramic comprises in mole % on oxide basis:SiO235-50,B2O3 5-15,Al2O3 0-5,MO30-50, andM2O 0-<1. 16. The feed-through element according to claim 1, wherein the glass or glass ceramic comprises in mole % on oxide basis:SiO235-50,B2O3 5-15,Al2O3 0-<2,MO30-50, andM2O 0-<1. 17. The feed-through element according to claim 1, wherein the glass or glass ceramic is essentially free of materials selected from the group consisting of M2O, PbO, fluorines, and any combinations thereof. 18. The feed-through element according to claim 1, wherein the glass or glass ceramic additionally comprises in mole % on oxide basis:ZrO20-10,Y2O30-10, andLa2O30-10. 19. The feed-through element according to claim 1, wherein the glass or glass ceramic comprises up to 30% of volume of fillers. 20. The feed-through element according to claim 19, wherein the fillers are selected from the group consisting of ZrO2, Al2O3, MgO, and any combinations thereof. 21. The feed-through element according to claim 1, wherein the access opening has an inner access opening wall with a structure that prevent movement of the electrically insulating fixing material in relation to the support body. 22. The feed-through element according to claim 1, wherein the access opening has at least a region with a cylindrical or truncated profile. 23. The feed-through element according to claim 1, further comprising a connector element having a structure that prevents movement of the connector element in relation to the electrically insulating fixing material and the support body when pressure is exerted on the feed-through element. 24. A downhole oil and/or gas drilling or exploration device comprising the feed-through element according to claim 1. 25. A containment of an energy generation or energy storage device comprising the feed-through element according to claim 1. 26. A containment of a reactor or storage device of toxic and/or harmful matter comprising the feed-through element according to claim 1. 27. A spacecraft or space rover vehicle comprising the feed-through element according to claim 1. 28. A sensor or actuator being encapsulated within a housing comprising the feed-through element according to claim 1.
054770530	abstract	This invention relates to a radiographic intensifying screen excellent in sharpness and durability, which comprises a support, a fluorescent layer formed on the support, and a protective layer formed by coating a solution containing a protective layer-forming resin on the fluorescent layer, wherein a water repellent layer or a resin layer which may optionally contain a water repellent is provided between the fluorescent layer and the protective layer, or the fluorescent layer may optionally contain a water repellent, and also relates to a process for preparing the same.
	summary
	claims	1. A beam steering system for a tunable monochromator, the system comprising:a first diffraction element configured to reflect, as a reflected beam, an input beam incident on a surface of the first diffraction element, the input beam having an input beam vector, the first diffraction element rotatable about the input beam vector, the reflected beam having a reflected beam vector; anda second diffraction element configured to reflect, as an output beam having a beam exit angle, the reflected beam incident on a surface of the second diffraction element, and the second diffraction element rotatable about both the input beam vector and the reflected beam vector. 2. The beam steering system of claim 1, wherein the first diffraction element and the second diffraction element each comprise crystal. 3. The beam steering system of claim 1, wherein the first diffraction element and the second diffraction element each comprise a multilayer. 4. The beam steering system of claim 1, wherein the first diffraction element and the second diffraction element each comprise a grating. 5. The beam steering system of claim 1, wherein the output beam has an energy in the x-ray radiation range. 6. The beam steering system of claim 1, wherein the beam exit angle is a fixed angle. 7. The beam steering system of claim 1, further comprising:a first mount physically coupled to the first diffraction element, the first mount configured to rotate the first diffraction element about the input beam vector; anda second mount physically coupled to the second diffraction element, the second mount configured to rotate the second diffraction element about the input beam vector and the reflected beam vector. 8. The beam steering system of claim 7, further comprising a three-axis translation stage physically coupled to the second diffraction element, the three-axis translation stage configured to translate the second diffraction element in three orthogonal directions. 9. The beam steering system of claim 8, further comprising:a controller communicatively coupled to (i) the first mount, the controller configured to control the rotation of the first diffraction element, (ii) the second mount, the controller configured to control the rotation of the second diffraction element, and (iii) the three-axis translation stage, the controller configured to control the position of the second diffraction element; anda processor communicatively coupled to the controller, the processor configured to provide the controller with (i) rotational coordinates of the first diffraction element, (ii) rotational coordinates of the second diffraction element, and (iii) translational coordinates of the second diffraction element. 10. The beam steering system of claim 1, wherein the first diffraction element is physically configured such that the input beam has an angle of incidence on the first diffraction element, with the angle of incidence being determined by a desired energy of the output beam. 11. A method for tuning output beam energy of a tunable monochromator, the method comprising:rotating a first diffraction element around an input beam vector by a first angle value, the first diffraction element configured to reflect, as a reflected beam having a reflected beam vector, an input beam having the input beam vector;rotating a second diffraction element around the input beam vector by the first angle value;rotating the second diffraction element around the reflected beam vector by a second angle value; andreflecting, by the second diffraction element, the reflected beam as an output beam having a beam exit angle. 12. The method of claim 11, wherein the first diffraction element and the second diffraction element each comprise crystal. 13. The method of claim 11, wherein the first diffraction element and the second diffraction element each comprise a multilayer. 14. The method of claim 11, wherein the first diffraction element and the second diffraction element each comprise a grating. 15. The method of claim 11, wherein the output beam has an energy in the x-ray radiation range. 16. The method of claim 11, wherein the output beam has a fixed beam exit angle. 17. The method of claim 11, further comprising:rotating, by a first mount physically coupled to the first diffraction element, the first diffraction element about the input beam vector; androtating, by a second mount physically coupled to the second diffraction element, the second diffraction element about the input beam vector and the reflected beam vector. 18. The method of claim 17, further comprising translating, by a three-axis translation stage physically coupled to the second diffraction element, the second diffraction element. 19. The method of claim 18, further comprising:a controller communicatively coupled to (i) the first mount, (ii) the second mount, and (iii) the three-axis translation stage, the controller configured to:control the rotation of the first diffraction element;control the rotation of the second diffraction element; andcontrol the position of the second diffraction element;and;provide, by a processor communicatively coupled to the controller, the controller with (i) rotational coordinates of the first diffraction element, (ii) rotational coordinates of the second diffraction element, and (iii) translational coordinates of the second diffraction element. 20. The method of claim 11, further comprising:positioning the first diffraction element such that the input beam has an angle of incidence on the first diffraction element, with the angle of incidence being determined by a desired energy of the output beam.
	summary
049845101	abstract	A sphincter seal, to accommodate variations in diameters of drums, is employed at a posting port into a containment. The seal comprises an annular assembly of inner and outer brush seals between which are sandwiched rings of resilient material. An elastic garter is secured to the resilient rings to resist deformation of the rings through use.
	abstract	A radiation resistant high-entropy alloy is provided, having an FCC structure, defined by general formula of FeCoNiVMoTixCry, where 0.05≤x≤0.2, 0.05≤y≤0.3, x and y are molar ratios. The radiation resistant high-entropy alloy has excellent irradiation resistance and is subject to radiation hardening saturation at high temperature (600° C.) in a condition of a high dose (1-3×1016 ions/cm2) of helium ion irradiation. A lattice constant of the high-entropy alloy decreases abnormally after irradiation. The high-entropy alloy has a radiation resistance far higher than that of a conventional alloy and has an excellent plasticity and specific strength. In an as-cast condition and at room temperature, a tensile break strength of the high-entropy alloy is higher than 580 MPa, an engineering strain (a tensile elongation) of the high-entropy alloy is greater than 30%.
	summary
044951442	description	DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, the preferred embodiment of the monitoring system of the present invention includes fission chamber detectors 10, a preamplifier and signal conditioning unit 11, and a signal processor and display unit 12. The fission chamber detectors are located inside the biological shield 14 that surrounds the reactor core 15. The preamplifier and signal conditioning unit 11 is located outside the containment vessel 16, usually within about five hundred feet (one hundred fifty meters) of the fission chambers 10. The preamplifier and signal conditioning unit 11 is connected to the fission chambers 10 by a plurality of coaxial cables 17. The signal processor and display unit 12 is located in a control room remote from the containment vessel and is connected to the preamplifier and signal conditioning unit by a plurality of twisted shielded pairs 19. Each of the coaxial cables 17 is uniquely constructed for withstanding high pressure, high temperature and high nuclear radiation and for shielding against electrical noise. Referring to FIG. 2, each coaxial cable includes a center conductor 20 closely covered by a thin coaxial high temperature insulating layer 21, which in turn is closely covered by a relatively thick coaxial dielectric layer 22 for withstanding nuclear radiation. The dielectric layer is closely covered by a solid coaxial sheath layer 24 of a conductive metal, such as copper. Preferably, the solid sheath layer 24 is 14 mils (0.35 mm) thick bare copper that has an outside diameter of 0.25 inch (6.35 mm); the shielding layer 22 is cross-linked polyethylene for shielding against approximately 10.sup.9 rads of nuclear radiation; the insulating layer 21 is poly(amide-imide) for providing insulation against temperatures up to about 200 degrees Centigrade; and the center conductor is 12 AWG bare copper wire. This combination of materials also withstands such high pressures, temperature, and nuclear radiation as are likely to be encountered within the containment vessel 16 in the event of a loss-of-coolant accident. The cross-sectional area of the sheath layer 24 is similar to the cross-sectional area of the center conductor 20 and both have low resistance for reducing attenuation and increasing noise immunity. Referring to FIG. 3, all of the fission chambers 10 are contained in a single container 25. Coaxial cables 17a with coaxial connectors are individually connected to the respective coaxial connectors 51 of the fission chambers for conducting neutron signal pulses to preamplifiers 27 contained in the preamplifier and signal conditioning unit 11. The coaxial cables 17a are collected within a flexible metal hose 29a and passed through to a first junction box 31. The coaxial cables 17a are coupled to extended coaxial cables 17b by connectors 33 within the first junction box 31 so that if it is necessary to replace the coaxial cables 17a from within the biological shield 14, one will not necessarily have to replace any of the remaining coaxial cables 17b, 17c or 17d extending outward through the wall of the containment vessel 16 to the preamplifiers 27. The coaxial cables 17b extending outward from the first junction box 31 are also collected in a flexible metal hose 29b, which carries the coaxial cables 17b to a second junction box 32 adjacent the inside of the wall of the containment vessel 16. Inside the second junction box 32, the coaxial cables 17b are separated and passed through separate flexible metal hoses 29c. The coaxial cables 17b and the flexible metal hoses 29c are connected to conductors 17c that penetrate the wall of the containment vessel 16. Such connection is by high pressure coaxial or triaxial connector fittings 34b. The conductors 17c continue through the wall of the containment vessel 16, and are connected to coaxial cables 17d that pass through separate flexible metal hoses 29d. The metal hoses 29d and the coaxial cables 17d are connected at the outside of the wall of the containment vessel 16 by high pressure coaxial or triaxial connector fittings 34b to the conductors 17c. The cables 17d pass into a third junction box 35 adjacent the outside of the wall. The junction boxes 31, 32 and 35 are high pressure junction boxes and the fittings 34a used to connect the flexible metal hose 29a, 29b, 29c, 29d and 29e to the junction boxes are high pressure fittings. The junction boxes are sealed by materials for withstanding such levels of gamma radiation as would be expected to occur in the event of a loss-of-coolant accident. The metal hoses 29a, 29b, 29c, 29d and 29e protect the coaxial cables 17 and associated coaxial connectors from potentially destructive contaminants under high pressure. The metal pipe 30 provides structural support for the coaxial cables 17a and the flexible metal hose 29a to prevent flexure in the zone of high nuclear radiation. Inside the third junction box 35, the coaxial cables 17b are again collected into a single flexible hose 29e, through which they pass to the inside of the preamplifier and signal conditioning unit 11, where they are separated and coupled to separate preamplifiers 27. The solid sheath layer 24 (FIG. 2) is coaxially covered by an outer insulating layer 28 for electrically insulating the coaxial cables 17 (FIG. 3) from the metal hose 29. The outer insulating layer must be capable of withstanding high nuclear radiation and high temperature. Referring to FIG. 4, the container 25 in which the fission chambers 10 are contained is a pressure-resistant cylindrical container. The fission chambers 10 are held in place laterally by a spacer 36 having a shoulder 37 for engaging the chambers 10. The fission chambers 10 are held in place longitudinally by a spring 39 which consists of an aluminum cylinder, which has a wall thickness of 0.25 inch (0.62 cm) and a spiral groove 40 that is 0.125 inch (0.31 cm) wide. The fission chambers 10 are electrically insulated from the container 25. The container 25 is sealed by an end cap 41. The end 42 of the container 25 is cut at an angle of 45 degrees. The end cap 41 has a side surface 44 that flares in at an angle of 45 degrees to mate with the end surface 42 of the container 25. The end cap 41 is threaded into the container 25 to provide a metal to metal seal between the end cap 41 and the container 25. The pipe 30 (FIG. 3) is threaded into the end cap 41. The container 25 is positioned vertically in a detector thimble (not shown) mounted inside the biological shield 14. The detector thimble diameter is different in different installations. The outside diameter of the container 25 is less than the inside diameter of the detector thimble. Adjustable wedges 48 are included on end cap 41 for wedging the container 25 within the detector thimble so that the container 25 remains stationary. The adjustable wedges 48 are eccentric cams. Referring to FIG. 5, each fission chamber 10 is of standard construction except that the coaxial connector 51 is tightly sealed to the body 52 of the fission chamber 10 by a metal O-ring 50. FIG. 6 illustrates how the solid sheath 24 is tightly sealed to a standard coaxial cable connector 53. The connector 53 has a conductive body 54. One end 55 of the body 54 is adapted for connecting the center conductor 20 of the coaxial cable to another conductive element, such as an electrode, a terminal or another coaxial cable center conductor. Such construction is standard and need not be further discussed. A special conductive adapter 56 is sealed to the other end of the connector body 54. The adapter has exterior threads 57 at one end which are tightly sealed to the interior threads 58 of the connector body 54. The conductive adapter 56 includes a bore 59 that closely fits around the solid sheath 24. The other end of the adapter 56 has exterior threads 60. A conductive ferrule 61 is closely fitted over the solid sheath 24 at the other end of the adapter 56. A nut 62 is screwed onto the exterior threads 60 of the adapter and pinches the ferrule 61 between the adapter 56 and the nut 62 to seal the solid sheath 24 to the conductive body 54 against contaminants under high pressure. FIG. 7 shows an alternative embodiment of a conductive adapter 63 for tightly sealing the solid sheath 24 to the conductive body 54 of a standard coaxial cable connector 53. The alternative adapter 63 has a flange 64 that is sealed to the end surface 65 of the connector body 54 by high temperature solder, brazing or welding. The adapter 63 does not have threads at the one end which engage the connector body 54, such as the threads 57 of the adapter 56 in the embodiment of FIG. 6. In other respects, the adapter 63 is identical to the adapter 56 and is connected to the solid sheath 24 in the same manner as the adapter 56. The electronic circuit aspects of the monitoring system are described with reference to FIGS. 8, 9, and 10. Referring first to FIG. 8, within the fission chamber container 25, there are four fission chamber detectors, as symbolized by electrodes 66 and shields 67 and 69. The electrodes 66 of the fission chambers are respectively connected to the inputs of the preamplifiers 27. The outer electrode 69 of one of the fission chamber detectors is connected by a line 71 to a current amplifier 72 in the preamplifier and signal conditioning unit 11. The preamplifier and signal conditioning unit 11 further includes four very sensitive threshold detectors 74, a less sensitive threshold detector 75, a band pass filter and full wave rectifier circuit 76, an OR gate and cable driver circuit 77, a second cable driver circuit 79, an operation monitoring circuit 80, an excitation voltage circuit 81, and a DC power supply circuit 82. The excitation voltage circuit 81 provides a high voltage signal on line 83 to a high voltage input terminal 84 of each of the preamplifiers 27, as shown in FIG. 9. The DC power supply circuit 82 provides DC voltage supply signals to each of the other components of the unit 11 as required. It is adapted for connection to an AC line supply voltage power source. The output of the DC power supply circuit 82 are connected by line 85 to the operation monitoring circuit 80 so that the operation of the DC power supply 82 can be monitored. The power supply connections from the DC power supply 82 are not shown in the Drawing. The output of each of the preamplifiers 27 is connected via lines 86 to the input of each of the very sensitive threshold detectors 74. The output of each of the threshold detectors 74 are connected via the lines 99 to the input of the OR gate and cable driver circuit 77. The output of the preamplifier 27a also is connected via line 86a to the input of the less sensitive threshold detector 75 and via line 86b to the input of the bandpass filter and fullwave rectifier circuit 76. The output of the less sensitive threshold detector 75 and the output of the bandpass filler and fullwave rectifier circuit 76 are respectively coupled by lines 87 and 89 to the input of the second cable driver circuit 79. The operation monitoring circuit monitors an alpha current signal provided on line 71 from the fission chamber electrode 69, the high voltage signal on line 83 from the excitation voltage circuit 81 and the supply voltage signal on line 85 from the DC power supply circuit 82. The output of the operation monitoring circuit 80 is connected via line 90 to an alarm device 93 as shown in FIG. 10. When the operation monitoring circuit 80 detects an irregularity in any of the signal on line 71 from the fission chamber outer electrode 69, the signal on line 83 from the excitation voltage circuit 91, or the signal on line 85 from the DC power supply circuit, the operation monitoring circuit 80 provides an alarm signal via line 90 to the alarm device 93 (FIG. 10). FIG. 9 shows the detail of an input stage of the preamplifier circuit 27a. The input stage includes a control terminal 91, a coaxial cable input terminal 92, capacitances C1, C2 and C3, resistances R1, R2, R3, R4, R5, R6 and R7, protective diodes D1, D2 and D3 and a field effect transistor (FET) Q1. The resistance R1 is connected between the high voltage input terminal 84 and the coaxial cable input terminal 92. The capacitance C1 and the resistance R2 are connected in series between the coaxial cable input terminal 92 and an input conduction terminal of the FET Q1. The capacitance C2 is connected between the high voltage input terminal 84 and circuit ground. The diode D1 is connected between the input conduction terminal of the FET Q1 and circuit ground for enabling conduction to circuit ground of a signal that is more than 0.7 volts above circuit ground. The diodes D2 and D3 are connected in series between the input conduction terminal of the FET Q1 and circuit ground for enabling conduction to circuit ground of a signal that is more than 1.4 volts below circuit ground. The resistance R3 is connected between the control terminal 91 and the gate of the FET Q1. The resistance R4 and the capacitance C3 are connected in parallel between the gate of the FET Q1 and circuit ground. The resistance R5 is connected between the control terminal 91 and the output conduction terminal of the FET Q1 and the resistance R6 is connected between the output conduction terminal of the FET Q1 and an input stage output terminal 95. The resistances R5 and R6 provide a conduction path from the control terminal 91 to the input stage output terminal 95. The resistance R7 is connected between the input stage output terminal 95 and a negative bias voltage terminal 94. The resistance R1 and capacitance C2 are for filtering electrical noise from a high voltage signal applied to the terminal 84. The capacitance C1 is a coupling capacitance. The protective diode D1 protects the preamplifier 27a against excessively large positive voltage excursions at the input terminal 92; and the protective diodes D2 and D3 protect the preamplifier against excessively large negative voltage excursions at the input terminal 92. A negative bias voltage is applied to terminal 94. The values of the resistances R3, R4, R5, R6 and R7 are chosen to provide a control circuit for the FET Q1 such that when a first predetermined voltage signal is applied to the terminal 91, the FET Q1 is enabled to pass input neutron signal pulses received at the coaxial cable input terminal 92 onto the input stage output terminal 95; and such that when a higher second predetermined voltage signal is applied to the terminal 91, the FET Q1 is inhibited from conduction. The preamplifier 27a further contains a high frequency current amplifier (not shown) which has an input transistor having its emitter connected to the output terminal 95 of the input stage shown in FIG. 9. The value of the resistance R2 in the input stage is chosen so that when the FET Q1 is on, the resistance of the series combination of the resistance R2, the resistance of the FET Q1, the resistance R6 and the resistance of the emitter of the input transistor in the high frequency current amplifier (not shown) matches the characteristic impedance of the coaxial cable connected to the coaxial cable input terminal 92. This reduces neutron signal reflection in the coaxial cable. The control circuit for the FET Q1 also enables the FET Q1 to be inhibited from conducting neutron signal pulses received from a fission chamber detector 10 at the coaxial cable input terminal 92 when it is desired to provide a test signal to the preamplifier 27a. A test signal generator 96 is included in the signal processor and display unit 12 (FIG. 10) for providing a test signal via line 97 to the control terminal 91 of the input stage of the preamplifier 27a. The test signal generator 96 provides a test signal, having a voltage level equal to or exceeding the second predetermined voltage level required for inhibiting the FET Q1 from conducting. Accordingly, the input stage of the preamplifier 27a can be controlled remotely for inhibiting the passage of neutron signals received from a fission chamber 10 through the preamplifier 27a, and for enabling a test signal to be passed through the preamplifier 27a in lieu of the received signals. All of the preamplifiers 27 are constructed in the same manner as the preamplifier 27a. However, in the preferred embodiment, only the preamplifier 27a has its control terminal 91 connected to the test signal generator 96. Each of the preamplifiers 27 is packaged in a separate module and operates independently of the other preamplifiers; whereby if one preamplifier fails, the other preamplifiers 27 and the system continue to operate, and repairs can be made without having to disable the entire system. Neutron signal pulses received by the preamplifiers 27 via the lines 70 from the fission chamber 10 are amplified to provide amplified pulses on the lines 86 to the very sensitive threshold detector 74. The very sensitive threshold detectors 74 detect only those pulses on the lines 86 that exceed a predetermined low threshold and provide detected signals respectively containing a corresponding number of detected pulses on lines 99 to the OR gate and cable driver circuit 77. The OR gate and cable driver circuit 77 provides a high level pulsed digital signal on line 100 that is representative of multi-level neutron signal pulses received from the fission chamber detectors 10. As a result of such conditioning by the very sensitive threshold detectors 74 and the OR gate and cable driver circuit 77, the high level pulsed digital signal provided on line 100 can be transmitted to the remotely located signal processing and display unit 12 by twisted shielded pairs 19 (FIG. 1) rather than by more expensive coaxial cables, as is done in prior art systems. The less sensitive threshold detector 75 is connected to the preamplifier 27a for detecting only those pulses on line 86a from the preamplifier 27a that exceed a higher second predetermined threshold and provides a second detected signal containing a corresponding number of detected pulses on line 87 to the cable driver circuit 79. The bandpass filter and fullwave rectifier circuit 76 is connected to the preamplifier 27a for conditioning the amplified neutron signal pulses on line 86b to provide a conditioned mean voltage signal on line 89 that has a DC level that is proportional to the square root of reactor power. The line cable driver circuit 79 combines the signals on lines 87 and 89 to provide a combined signal on line 101. The combined signal includes high level digital pulses that are representative of high level neutron signal pulses received from a fission chamber detector 10, and a DC signal component derived from the conditioned mean voltage signal on line 86b that is proportional to the square root of reactor power. As a result of such conditioning by the less sensitive threshold detector 75, the bandpass filter and full wave rectifier circuit 76 and the cable driver circuit 79, the combined signal provided on line 101 can be transmitted to the remotely located signal processing and display unit 12 by twisted shield pairs 19 (FIG. 1). The current amplifier 72 is connected to the fission chamber shield 69 for providing an amplified signal on line 102 that is representative of a direct current signal on line 71 from the fission chamber detector. Referring to FIG. 10, the signal processor and display unit 12 includes the test generator 96, a first log countrate circuit 104, a second log countrate circuit 105, a log mean square voltage circuit 106, first, second and third differentiators 107, 108 and 109, a voltage controlled switch 110, a slave switch 111, a scaling amplifier 112, a calibration circuit 113, a first reactor power display 115, a first reactor power rate-of-change display 116, a second reactor power display 117, a second reactor power rate-of-change display 118, a linear power display 120 and the alarm device 93. The first log countrate circuit 104 processes the pulsed signal on line 100 to provide a first power signal on line 122 that is proportional to the logarithm of the rate of pulses in the pulsed signal on line 100. The signal on line 122 is proportional to the logarithm of reactor power in a first power range that includes power levels which prevail when the reactor is started. In this embodiment the first power signal provided on line 122 represents reactor power in a first power range of from 10.sup.-12 to 10.sup.-6 times full reactor power. The power display 115 is connected to line 122 to display an indication of reactor power within this range. The first differentiator 107 differentiates the first power signal on line 122 to provide a first rate-of-change signal on line 123 that is proportional to the rate of change of the logarithm of reactor power when reactor power is in the first power range. The first reactor power rate-of-change display 116 is connected to line 123 to display an indication of the rate of change of reactor power. The second log countrate circuit 105 processes the combined signal on line 101 to provide a second power signal on line 124 that is proportional to the logarithm of the rate of pulses in the signal on line 101. The second power signal on line 124 is proportional to the logarithm of reactor power in a second power range of from 10.sup.-10 to 10.sup.-4 times full reactor power. At reactor power levels above this range, the pulses in the signal on line 101 occur at such frequency as to become indistinguishable. As a result, the log countrate circuit 105 is not capable of providing a meaningful output signal when the reactor power is above about 10.sup.-4 times full reactor power. In order to measure reactor power above 10.sup.-4 times full reactor power, the log mean square voltage circuit 106 processes the DC signal component of the combined signal on line 101 to provide a third power signal on line 126 that is proportional to the logarithm of the voltage of the condition means voltage signal on line 89. The third power signal on line 126 is proportional to the logarithm of reactor power in a third power range of from about 10.sup.-5 to 1 times full reactor power. This third power range includes the peak operating power of the reactor. The second differentiator 108 differentiates the second power signal on line 124 to provide a second signal on line 127 that is proportional to the rate of change of the logarithm of reactor power when reactor power is in the second power range. The third differentiator 109 differentiates the third power signal on line 126 to provide a third signal on line 129 that it is proportional to the rate of change of the logarithm of reactor power when reactor power is in the third power range. The reactor power ranges respectively represented by the first, second and third power signals on lines 122, 124 and 126 from the first log countrate circuit 104, the second log countrate circuit 105 and the log means square voltage circuit 106 overlap. The calibration circuit 113 is connected to the first log countrate circuit 104, the second log countrate circuit 105 and the log mean square voltage circuit 106 for calibrating such circuits so that the power signals produced therefrom respectively on lines 122, 124 and 126 correspond in the overlapping portions of the respective power ranges. The voltage-controlled switch 110 is connected to receive the second and third power signals from lines 124 and 126 and to pass the signals from line 124 onto output line 130 to the power display 117 when the voltage level of the signal on line 126 is less than a predetermined voltage that is representative of a reactor power level below the level at which the pulses on line 101 become so frequent as to become indistinguishable. When the voltage level of the signal on line 126 becomes equal to or exceeds such predetermined voltage, the voltage-controlled switch 110 passes the signals from line 126 onto the output line 130. The slave switch 111 is connected to the voltage controlled switch 110 to switch between its input lines when the master voltage-controlled switch 110 switches between its input lines. Accordingly, the slave switch is connected to receive signals from lines 127 and 129 and to pass the signals from line 127 onto output line 131 to the rate of change display 118 when the voltage level of the signal on line 126 is less than the predetermined voltage, and to pass the signals from line 129 onto output line 131 to the rate-of-change display 118 when the voltage level of the signal on line 126 is equal to or exceeds the predetermined voltage. As a result, the present invention provides simple alignment of the signals derived from pulse counting with the signals derived from the mean square voltage processing technique without incurring the spurious transients in the rate-of-change signals that were incident to the more complicated prior art alignment techniques. The power display 117 is connected to line 130 to display an indication of reactor power within the range of from 10.sup.-10 to 1 times full reactor power. The second reactor power rate-of-change display 118 is connected to line 131 to display an indication of the rate of change of reactor power. The signal on line 102 is provided to the scaling amplifier 112; and the linear power display 120 is connected to the scaling amplifier 112 for displaying an indication of power.
	description	This application claims the benefit of Korean Patent Application No. 10-2016-0131621, filed on Oct. 11, 2016, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. One or more embodiments relate to an installation structure for installing control rod drive mechanisms and cable sealing units in a nuclear reactor pressure vessel, and more particularly, to an installation structure having a structure, by which control rod drive mechanisms and cable sealing units may be installed together in a nuclear reactor pressure vessel, so that disassembling, assembling, and maintenance processes may be performed easily when replacing nuclear fuel. In general, nuclear fuel assemblies are loaded in a core of a nuclear reactor pressure vessel, and control rod drive mechanisms are installed on an upper portion of a nuclear reactor. A control rod absorbs neutrons in order to adjust a reaction rate of nuclear fuel, a control rod driving shaft is coupled to an upper end portion of the control rod, and the control rod drive mechanism is a device for elevating the control rod driving shaft in vertical direction. An in-vessel type control rod drive mechanism installed in a nuclear reactor is mainly used in small/medium-sized nuclear reactors. As described above, the in-vessel type control rod drive mechanism is installed in the nuclear reactor pressure vessel, and accordingly, cables for the control rod drive mechanisms are installed to penetrate through the nuclear reactor pressure vessel for supplying electric power from outside and transmitting/receiving a position signal of the control rod. A reactor coolant for heat exchange circulates in the nuclear reactor pressure vessel. A penetration tube that penetrates through the nuclear reactor pressure vessel for installing cables has to be sealed so as to prevent leakage of the reactor coolant during driving of the nuclear reactor, and to do this, a cable sealing unit is installed in the nuclear reactor pressure vessel. In order to replace the nuclear fuel, the nuclear reactor has to stop operating, and the control rod drive mechanisms and the cable sealing units exposed to the reactor coolant, which is a radioactive material, during the operation of the nuclear reactor have to be rapidly disassembled, assembled, and maintained. FIGS. 1 and 2 show an example of an instrumentation and control penetration flange for a pressurized water reactor according to the related art. Referring to FIGS. 1 and 2, a core 14 containing nuclear fuel is positioned on a lower portion in a reactor container 12, and a control rod drive mechanism (CRDM) is installed on an upper portion in the reactor container 12. A penetration flange 44 (or sealing ring) having a loop shape is installed between an upper end flange 42 of the reactor container 12 and a head 22 covering the reactor container 12, and the CRDM is installed in the reactor container 12 separately from the penetration flange 44. A plurality of ports 48 extending in a radial direction are formed in the penetration flange 44, and a utility conduit 50 is inserted in each of the plurality of ports 48 so that a cable may be inserted into the reactor container 12 via the utility conduit 50. As described above, according to the related art illustrated in FIG. 1, the penetration flange 44 is installed between the reactor container 12 and the head 22 to be located adjacent to the upper end portion of the CRDM, and the cable independently penetrates through the penetration flange 44. Thus, cables occupy a large wiring space, and it is difficult to perform the installation and maintenance. Also, the CRDM and the penetration flange 44 are configured as separate devices, and thus, a simple structure for easily maintaining and repairing the CRDM exposed to radioactive material may not be obtained. In addition, it is difficult to independently replace the cable sealing unit and the CRDM, and thus, an operator may be exposed to high risk and the related art is not economically efficient. One or more embodiments include an installation structure for installing control rod drive mechanisms and cable sealing units in a nuclear reactor pressure vessel, wherein the installation structure has an integrated structure that makes assembling, disassembling, and maintenance of the control rod drive mechanisms and the cable sealing units easy and reduces working hours in a highly-radioactive region so as to improve safety and economic feasibility. Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments. According to one or more embodiments, an installation structure for installing control rod drive mechanisms and cable sealing units in a nuclear reactor pressure vessel, the installation structure includes: a sealing flange having a ring shape and being hermetically coupled between an upper pressure vessel and a lower pressure vessel of the nuclear reactor pressure vessel; a cylindrical tube extending downward vertically from an internal edge of the sealing flange; and a support plate provided horizontally to block a lower end portion of the cylindrical tube, wherein a plurality of mounting holes that penetrate through the sealing flange horizontally are arranged in the sealing flange with predetermined intervals therebetween along a circumferential direction, the cable sealing units are inserted and mounted in the plurality of mounting holes, and the control rod drive mechanisms are installed on the support plate to be supported. A plurality of low temperature coolant passages that vertically penetrate through the sealing flange may be provided in the sealing flange with predetermined intervals therebetween along a circumferential direction. A low temperature coolant passage connecting recess having a ring shape that connects upper portions of the plurality of low temperature coolant passages to one another and communicates with the plurality of low temperature coolant passages may be formed in an upper surface of the sealing flange. A plurality of high temperature coolant passages may be formed in the support plate so as to vertically penetrate through the support plate. The plurality of low temperature coolant passages may be located at an outer portion of the cylindrical tube, and the plurality of high temperature coolant passages may be located at an inner portion of the cylindrical tube. A plurality of control rod driving shaft insertion holes, in which control rod driving shafts elevated by the control rod drive mechanisms are inserted, may be formed in the support plate so as to vertically penetrate through the support plate. A plurality of installation recesses, in which a lower end portion of the control rod drive mechanism is inserted, may be formed in an upper surface of the support plate, and the control rod driving shaft insertion hole may be formed at a center portion of each of the plurality of installation recesses. A plurality of cables may be led into the nuclear reactor pressure vessel through one cable sealing unit mounted in each of the plurality of mounting holes. The cable sealing unit may include a penetration tube that is fixedly inserted in the mounting hole of the sealing flange, a thimble inserted to the penetration tube, and a guide tube inserted into the thimble, and the plurality of cables may be inserted to the guide tube. Hereinafter, an installation structure for installing a control rod drive mechanism and a cable sealing unit in a nuclear reactor pressure vessel according to embodiments of the present disclosure will be described with reference to accompanying drawings. Throughout the specification, like reference numerals denote the same elements. FIG. 3 is a cross-sectional view schematically showing a state in which an installation structure 200 for installing a control rod drive mechanism 110 and a cable sealing unit 120 in a nuclear reactor pressure vessel 100 is installed in the nuclear reactor pressure vessel 100, FIG. 4 is a perspective view of the installation structure 200 of FIG. 3, and FIG. 5 is a cross-sectional view of the installation structure 200 taken along a line A-A of FIG. 4. Referring to FIGS. 3 to 5, the installation structure 200 according to the present embodiment is a structure for installing the control rod drive mechanism 110 and the cable sealing unit 120 in the nuclear reactor pressure vessel 100. The installation structure 200 according to the present embodiment may be applied to the nuclear reactor pressure vessel 100 of a mid-flange type. The nuclear reactor pressure vessel 100 of the mid-flange type is divided into an upper pressure vessel 101 and a lower pressure vessel 102, and the upper pressure vessel 101 and the lower pressure vessel 102 are hermetically coupled to each other via an upper flange 103 positioned on a lower end portion of the upper pressure vessel 101 and a lower flange 104 positioned on an upper end portion of the lower pressure vessel 102. A core containing a nuclear fuel 105 is positioned in the nuclear reactor pressure vessel 100, and the control rod drive mechanism 110 is positioned above the core. The control rod drive mechanism 110 is a device for vertically elevating a control rod driving shaft 112 coupled to an upper end portion of a control rod (not shown). The control rod drive mechanism 110 is installed on the installation structure 200 according to the present embodiment to be supported, and this will be described below in detail. The installation structure 200 according to the present embodiment is installed between the upper pressure vessel 101 and the lower pressure vessel 102 of the nuclear reactor pressure vessel 100. Therefore, the installation structure 200 is located at a middle portion in a height direction of the nuclear reactor pressure vessel 100. The installation structure 200 according to the present embodiment includes a sealing flange 210, a cylindrical tube 220, and a support plate 230. The sealing flange 210 has a ring shape and is installed between the upper pressure vessel 101 and the lower pressure vessel 102 of the nuclear reactor pressure vessel 100, in more detail, between the upper flange 103 and the lower flange 104. The sealing flange 210 is firmly coupled to the upper flange 103 and the lower flange 104 to seal a gap between the upper pressure vessel 101 and the lower pressure vessel 102 of the nuclear reactor pressure vessel 100. To do this, a plurality of coupling holes 212 penetrating through the sealing flange 210 in a vertical direction are arranged in the sealing flange 210 with predetermined intervals therebetween along a circumferential direction. A coupling unit, for example, a plurality of bolts (not shown), may be firmly coupled to the upper flange 103 and the lower flange 104 via the plurality of coupling holes 212. In addition, a unit for preventing leakage of the coolant in the nuclear reactor pressure vessel 100, for example, O-rings (not shown), may be provided on upper and lower surfaces of the sealing flange 210. A plurality of mounting holes 214 penetrating through the sealing flange 210 in a horizontal direction are radially arranged with predetermined intervals therebetween in an outer circumferential surface of the sealing flange 210. The cable sealing unit 120 is inserted into each of the plurality of mounting holes 214, and this will be described later with reference to FIGS. 10 and 11. In addition, a plurality of low temperature coolant passages 216 penetrating through the sealing flange 210 in a vertical direction are arranged in the sealing flange 210 with predetermined intervals therebetween along the circumferential direction. The plurality of low temperature coolant passages 216 are provided in the sealing flange 210 at a portion located inside the nuclear reactor pressure vessel 100, and a low temperature coolant flowing in the nuclear reactor pressure vessel 100 flows downward after passing through the plurality of low temperature coolant passages 216. Each of the plurality of low temperature coolant passages 216 may have a square-shaped cross-section as shown in FIG. 4, but is not limited thereto, that is, they may have a circular cross-section. The cylindrical tube 220 may extend a predetermined distance downward from an internal edge of the sealing flange 210 in a vertical direction. A length of the cylindrical tube 220 is determined based on cable wirings. The cylindrical tube 220 connects the support plate 230 that will be described later to the sealing flange 210. The sealing flange 210, the cylindrical tube 220, and the support plate 230 may be connected to one another by a welding process, but are not limited thereto. In addition, the cylindrical tube 220 may function as a separation wall for separating the low temperature coolant passing through the plurality of low temperature coolant passages 216 formed in the sealing flange 210 from the high temperature coolant passing through a plurality of high temperature coolant passages 236 formed in the support plate 230 that will be described later. That is, the low temperature coolant passages 216 are provided on an external portion of the cylindrical tube 220 and the high temperature coolant passages 236 are provided on an internal portion of the cylindrical tube 220, and thus, the low temperature coolant and the high temperature coolant are separate from each other based on the cylindrical tube 220 and thus flow in opposite directions. The support plate 230 is provided to block a lower end portion of the cylindrical tube 220. The support plate 230 may be installed at the lower end portion of the cylindrical tube 220 by a welding process, but is not limited thereto. The control rod drive mechanism 110 is installed on the support plate 230 to be supported. This will be described later with reference to FIGS. 8 and 9. The plurality of high temperature coolant passages 236 penetrate through the support plate 230 in a vertical direction as described above. The high temperature coolant flowing in the nuclear reactor pressure vessel 100 flows upward by passing through the plurality of high temperature coolant passages 236. FIG. 6 is a perspective view showing a modified example of the installation structure 200 of FIG. 4, and FIG. 7 is a cross-sectional view of the installation structure taken along a line B-B of FIG. 6. The installation structure 200 shown in FIGS. 6 and 7 is identical with the structure of the installation structure shown in FIGS. 4 and 5 except for the structure of the low temperature coolant passage, and thus, only differences between the installation structures will be described hereinafter. Referring to FIGS. 6 and 7, a low temperature coolant passage connecting recess 218 having a ring shape is formed to a predetermined depth in an upper surface of the sealing flange 210 for connecting upper portions of the plurality of low temperature coolant passages 216 to one another. The low temperature coolant passage connecting recess 218 is connected to the plurality of low temperature coolant passages 216. That is, the plurality of low temperature coolant passages 216 are formed in a bottom surface of the low temperature coolant passage connecting recess 218. According to the above structure, the passage in which the low temperature coolant flows may be ensured as much as possible, and a weight of the installation structure 200 may be reduced. FIG. 8 is a partial cross-sectional view schematically showing a structure in which the control rod drive mechanism 110 of FIG. 3 is coupled to the support plate 230 of the installation structure 200 of FIG. 5. Referring to FIG. 8, the control rod drive mechanism 110 is a device for elevating the control rod driving shaft 112 connected to the control rod (not shown). In the present disclosure, the control rod drive mechanism 110 is installed on the support plate 230 of the installation structure 200 to be supported. In detail, a lower end portion of the control rod drive mechanism 110 is fixedly installed on the support plate 230. To do this, a flange 114 may be provided at the lower end portion of the control rod drive mechanism 110, and a plurality of installation recesses 234 in which the flange 114 at the lower end portion of the control rod drive mechanism 110 are inserted to a predetermined depth are formed in the upper surface of the support plate 230. The control rod drive mechanism 110 may be fixedly installed on the support plate 230 by a fixing unit, e.g., a bolt 238, in a state in which the flange 114 at the lower end portion of the control rod drive mechanism 110 is inserted in the installation recesses 234. In addition, besides the plurality of high temperature coolant passages 236, a plurality of control rod driving shaft insertion holes 232, in which the control rod driving shaft 112 is inserted, penetrate through the support plate 230 in the vertical direction, and the control rod driving shaft 112 may elevate through the control rod driving shaft insertion holes 232. The control rod driving shaft insertion hole 232 is formed at a center portion of the installation recess 234. A detailed coupling structure between the control rod drive mechanism 110 and the support plate 230 above is just an example, and may vary depending on the structure of the control rod drive mechanism 110. FIG. 9 is a partial cross-sectional view showing an example in which a high temperature coolant passage 236 of FIG. 8 is installed at a different location. Referring to FIG. 9, the plurality of high temperature coolant passages 236 may be provided at the location where the control rod drive mechanism 110 is installed. In detail, the plurality of high temperature coolant passages 236 may be provided to penetrate through the support plate 230 in the vertical direction at the location where the installation recess 234 is formed. Here, the plurality of high temperature coolant passages 236 may also vertically penetrate through the flange 114 at the lower end portion of the control rod drive mechanism 110. Alternatively, the plurality of high temperature coolant passages 236 may be also provided at the location illustrated in FIG. 8, in addition to the location of FIG. 9. FIG. 10 is a partial cross-sectional view schematically showing a state in which the cable sealing unit 120 of FIG. 3 is coupled to the sealing flange 210 of the installation structure 200 of FIG. 5, and FIG. 11 is a schematic cross-sectional view of the structure of the cable sealing unit 120 of FIG. 10. Referring to FIG. 10, the cable sealing unit 120 is inserted and mounted to each of the plurality of mounting holes 214 that penetrate through the sealing flange 210. The cable sealing unit 120 includes a penetration tube 121 that is fixedly inserted into the mounting hole 214 of the sealing flange 210, and the penetration tube 121 includes an external end portion 122 and an internal end portion 123 blocking opposite ends thereof. The penetration tube 121 may be fixed to the sealing flange 210 by a welding process (W) in a state of being inserted in the mounting hole 214. Referring to FIG. 11, a thimble insertion hole 124 that penetrates through the external end portion 122 and the internal end portion 123 of the penetration tube 121 is formed, and a thimble 125 is inserted and installed in the thimble insertion hole 124. A guide tube 126 is inserted in the thimble 125, and at least one cable, e.g., a plurality of cables 127 are inserted in the guide tube 126 as a bundle. A plurality of protrusions 128 that are convex inward are formed from the thimble 125 to support the guide tube 126 not to be shaken. The cable 127 supplies electric power to the control rod drive mechanism 110 in the nuclear reactor pressure vessel 100 and transmits and receives control signals and location signals. In addition, although not shown in the drawings, a swagelok may be installed on an outer portion of the penetration tube 121 in order to finally seal the penetration tube 121. Since the swagelok is well known in the art, detailed descriptions thereof are omitted. In addition, one thimble 125 is installed penetrating through one cable sealing unit 120 in FIG. 11, but two or more thimbles 125 may be installed penetrating through one cable sealing unit 120, and at least one, for example, a plurality of cables 127 may be inserted in a bundle into each of the two or more thimbles 125. That is, according to the present disclosure, the plurality of cables 127 may be led in the nuclear reactor pressure vessel 100 via each of the plurality of mounting holes 214 that penetrate through the sealing flange 210. As described above, the installation structure 200 according to the present disclosure has a structure, in which the control rod drive mechanism 110 and the cable sealing unit 120 may be inserted together in the nuclear reactor pressure vessel 100, and thus, assembling, disassembling, and maintenance operations of the control rod drive mechanism 110 and the cable sealing unit 120 may be performed easily and collectively, working hours in a high-radioactive region may be reduced, and the control rod drive mechanism 110 and the cable sealing unit 120 may be independently replaced and thus economically efficient. Also, since the installation structure 200 is located at a middle portion in a height direction of the nuclear reactor pressure vessel 100, that is, at a location where the cables 127 of the control rod drive mechanism 110 are wired, wiring distances of the plurality of cables 127 may be reduced and spatial efficiency may be improved. Also, since the plurality of cables 127 are configured to penetrate through the sealing flange 210 of the installation structure 200 in a bundle, easiness in wiring and maintaining the plurality of cables 127 may be improved. Since the number of mounting holes 214 in which the cable sealing unit 120 is mounted may be reduced, it may be easy to maintain a pressure boundary and a flow resistance of the reactor coolant may be reduced in the nuclear reactor pressure vessel 100. In addition, since the plurality of low temperature coolant passages 216 and the plurality of high temperature coolant passages 236 are provided in the installation structure 200, the reactor coolant may sufficiently circulate in the nuclear reactor pressure vessel 100. According to the present disclosure, the installation structure for installing the control rod drive mechanism and the cable sealing unit in the nuclear reactor pressure vessel is integrally configured, and thus, the control rod drive mechanism and the cable sealing unit may be separated and moved at once from the nuclear reactor pressure vessel to be disassembled, assembled, and maintained in a separate and safe place. In addition, working hours in a highly-radioactive region may be reduced, an operator's exposure to radiation may be reduced and economic efficiency may be improved. Also, since the installation structure is located at a height where the cables are wired in the control rod drive mechanism and a plurality of cables penetrate through the sealing flange of the installation structure in a bundle, wiring distances of the plurality of cables may be reduced, and thus, a spatial efficiency may be improved and easiness in wiring and maintaining of the cables may be improved. It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the inventive concept as defined by the following claims.
044366558	abstract	A method and apparatus for removing and disposing of contaminants from a contaminated fluid makes use of an expendable collection receptacle which is encapsulated in an inert protective matrix except for inlet and outlet ports and which is capable of removing and retaining contamination from the liquid when passed therethrough. The removed and retained contamination is subsequently encapsulated in a solid material within the receptacle by introducing a settable fluid material into the receptacle. The inlet and outlet ports are then encapsulated in a solid inert matrix so that the receptacle can be disposed of.
	description	Embodiments of the present invention will be described below in detail with reference to the drawings. A first embodiment of the present invention will be described with reference to FIGS. 1 to 9. FIG. 2 is a conceptual block diagram showing an overall system configuration of a medical system including a radiation beam irradiator comprising a multi-leaf collimator of this embodiment and an accelerator. In the radiation beam irradiator, a radiation beam (also referred to simply as a xe2x80x9cbeamxe2x80x9d hereinafter), such as a charged particle beam, accelerated by an accelerator (synchrotron) 101 is outputted from a rotating irradiator 102 under control of a control unit 23 for irradiation to the diseased part of a patient K. By turning the rotating irradiator 102 about an axis of the rotation, the beam can be irradiated to the diseased part from a plurality of directions. (1) Outline and Operation of Synchrotron 101 The synchrotron 101 comprises a high-frequency applying apparatus 111 for applying a high-frequency magnetic field and electric field (referred to together as a xe2x80x9chigh-frequency electromagnetic fieldxe2x80x9d hereinafter) to the beam to increase the amplitude of betatron oscillation of the beam; deflecting electromagnets 112 for bending a track of the beam; quadrupole electromagnets 113 for controlling the betatron oscillation of the beam; hexapole electromagnets 114 for exciting resonance for exiting of the beam; a high-frequency accelerating cavity 115 for accelerating the beam; an inlet unit 116 for introducing the beam into the synchrotron 101, and outlet deflectors 117 for guiding the beam to exit the synchrotron 101. When the control unit 23 outputs an emission command to a pre-stage accelerator 104, the pre-stage accelerator 104 emits a beam of low energy in accordance with the emission command. The beam is guided to the inlet unit 116 of the synchrotron 101 through a beam transporting system, and then introduced to the synchrotron 101. The introduced beam goes around within the synchrotron 101 while its track is bent by the deflecting electromagnets 112. While the beam is going around within the synchrotron 101, it undergoes the betatron oscillation under actions of the quadrupole electromagnets 113. The oscillation frequency of the betatron oscillation is properly controlled in accordance with the amount of excitation of the quadrupole electromagnets 113 so that the beam stably orbits within the synchrotron 101. During the orbiting, a high-frequency magnetic field is applied to the beam in the high-frequency accelerating cavity 115, whereby energy is applied to the beam. As a result, the beam is accelerated and the beam energy is increased. When the energy of the beam orbiting within the synchrotron 101 is increased to a level of energy E, the application of energy to the beam in the high-frequency accelerating cavity 115 is stopped. At the same time, a gradient of the beam orbit is changed under well-known control by the quadrupole electromagnets 113, the hexapole electromagnets 114 and the high-frequency applying apparatus 111. The magnitude of the betatron oscillation is hence abruptly increased due to resonance, causing the beam to exit the synchrotron 101 through the outlet deflectors 117. In the above-described operation of the synchrotron 101, in accordance with the depth position of the diseased part inputted from a remedy scheduling unit 24 (described later in detail), the control unit 23 determines the energy E of the beam that is to be irradiated to the diseased part in a predetermined irradiating direction (usually the beam is irradiated in plural directions). Further, the control unit 23 calculates patterns of current values supplied to the deflecting electromagnets 112, the quadrupole electromagnets 113 and the high-frequency accelerating cavity 115 for accelerating the beam in the synchrotron 101 to a level of the energy E, and also calculates current values supplied to the high-frequency applying apparatus 111 and the hexapole electromagnets 114 for emitting the beam of the energy E. The calculated current values are stored in a storage means in the control unit 23 corresponding to levels of the energy E for each component, and are outputted to a power supply 108 or 109 when the beam is accelerated or exits. (2) Outline and Operation of Rotating Irradiator 102 The beam exiting the synchrotron 101 enters the rotating irradiator 102. The rotating irradiator 102 comprises a gantry 122, on which deflecting electromagnets 123, quadrupole electromagnets 124 and an outlet nozzle 120 are mounted, and a motor 121 for rotating the gantry 122 about a predetermined axis of rotation (see FIG. 2). The beam having entered the rotating irradiator 102 is introduced to the outlet nozzle 120 while the beam track is bent by the deflecting electromagnets 123 and the betatron oscillation is adjusted by the quadrupole electromagnets 124. The beam introduced to the outlet nozzle 120 first passes between scanning electromagnets 201, 202. Sinusoidal AC currents being 90 degrees out of phase are supplied to the scanning electromagnets 201, 202 from power supplies 201A, 202A. The beam passing between magnet poles of the scanning electromagnets 201, 202 is deflected by magnetic fields generated from the scanning electromagnets 201, 202 so that the beam makes a circular scan at a position of the diseased part. The beam having passed the scanning electromagnets 201, 202 is diffused by a diffuser 203 so as to have an enlarged diameter, and then passes a ridge filter 204A (or 204B). The ridge filter 204A (or 204B) attenuates the beam energy at such a predetermined rate that the beam energy has a distribution corresponding to a thickness of the diseased part. The radiation dose is then measured by a dosimeter 205. Thereafter, the beam is introduced to a porous member 206A (or 206B) that gives the beam an energy distribution corresponding to a bottom shape of the diseased part. Further, the beam is shaped by a multi-leaf collimator 200 in match with a horizontal shape of the diseased part, and then irradiated to the diseased part. Usually, as mentioned above, the beam is irradiated to the diseased part from a plurality of directions. This embodiment shows, by way of example, the case of irradiating the diseased part from two directions. Two ridge filters 204A, 204B are fabricated beforehand for each of the two irradiating directions corresponding to respective values of thickness of the diseased part determined by the remedy scheduling unit 24. Also, the porous members 206A, 206B are fabricated beforehand for each of the two irradiating directions corresponding to respective bottom shapes of the diseased part determined by the remedy scheduling unit 24. The fabricated ridge filters 204A, 204B are mounted on a rotating table 204C, and the fabricated porous members 206A, 206B are mounted on a rotating table 206C. An axis of rotation of the rotating table 206C is offset from the center of the beam track. By turning the rotating table 206C, therefore, the porous member 206A or 206B can be alternately arranged to lie across the beam track, and the beam having an energy distribution corresponding to each of the two irradiating directions can be formed. Additionally, the rotating table 206C is of the same construction as the rotating table 204C. When setting or changing the irradiating direction, an inclination angle signal corresponding to the irradiating direction is outputted from the control unit 23 to the motor 121, whereupon the motor 121 rotates the gantry 122 to an inclination angle indicated by the outputted signal and the rotating irradiator 102 is moved to a position where it is able to irradiate the beam to the diseased part from the selected irradiating direction. Also, the control unit 23 outputs, to the rotating tables 204C and 206C, signals for instructing them to arrange the ridge filter 204A (or 204B) and the porous member 206A (or 206B), corresponding to the selected irradiating direction, so as to lie across the beam track. The rotating tables 204C, 206C are rotated in accordance with the instruction signals. Then, a control signal corresponding to the selected irradiating direction is outputted from the control unit 23 to a collimator controller (leaf position control computer) 22. Responsively, the collimator controller 22 makes control such that, as shown in FIG. 3, a number of leaf plates 1 (described later in detail) provided in the multi-leaf collimator 200 are positioned in an opposing relation to provide a gap space G, which defines an irradiation area (field) F of a beam X in match with a horizontal shape of the diseased part as viewed in the selected irradiating direction. As a result, of the beam having reached the multi-leaf collimator 200 after passing the porous member 206A (or 206B), a component directing to other areas than the irradiation field F is shielded by the leaf plates, and the irradiation to an unnecessary part can be prevented. Important features of the present invention reside in mechanisms for driving the leaf plates of the multi-leaf collimator 200. Details of those features will be described below in sequence. (3) Basic Construction and Operation of Multi-leaf Collimator 200 FIG. 1 is a perspective view showing the detailed structure of the multi-leaf collimator 200; FIG. 4 is a front view as viewed in the direction of A in FIG. 1; FIG. 5 is a plan view of the multi-leaf collimator in a state where an upper coupling portion 201a (described later) and an upper support 7a (described later) of a leaf plate driver 200R (described later); and FIG. 6 is a plan view as viewed in the direction of B in FIG. 5. Referring to FIGS. 1, 4, 5 and 6, the multi-leaf collimator 200 comprises leaf plate driving body 200L and 200R. Each leaf plate driver 200L or 200R comprises a plurality (twelve in this embodiment, but the number may be greater than it) of leaf plates 1, which are movable to form the irradiation field F of the radiation beam and capable of shielding the radiation beam; an upper guide 3 and a lower guide 5 for receiving an upper sliding portion 1A and a lower sliding portion 1B of each leaf plate 1, respectively, and supporting them to be slidable in the longitudinal direction of the leaf plate 1 (left and right direction in FIG. 4); upper air cylinders 2 and lower air cylinders 4 capable of pressing the upper guide 3 and the lower guide 5 upward and downward, respectively; a support structure 7 including an upper support 7a and a lower support 7b for fixedly supporting the upper air cylinders 2 and the lower air cylinders 4, respectively, and an intermediate portion 7c connecting the upper support 7a and the lower support 7b; a motor 8 provided as a driving source for the leaf plates 1; a pinion gear 6 disposed coaxially with a drive shaft 8a of the motor 8 and connected to the drive shaft 8a on the side of the intermediate portion 7c; and a braking plate 9 brought into contact with the leaf plates 1 for holding them stationary by frictional forces (as described later in detail). The motor 8 is a known servo motor in this embodiment. A motor and a rotary encoder are coaxially arranged as an integral unit, and a pulse signal is outputted for each certain small angle of rotation. The upper air cylinders 2 and the lower air cylinders 4 are each constituted by a known single- or double-actuated air cylinder. For example, a piston is disposed in a cylindrical cylinder chamber, and a rod projecting out of the cylinder chamber is attached to the piston. In an operative condition, compressed air from a compressed air source is supplied to a bottom-side chamber, whereupon the piston is moved to the rod side by overcoming the biasing force of a spring disposed on the rod side. As a result, the rod is extended. Upon shift to an inoperative (stop) condition, the compressed air supplied to the bottom-side chamber is discharged (for example, by being made open to the atmosphere), whereby the piston is returned to the bottom side by the biasing force of the spring. As a result, the rod is contracted for return to the original position. The leaf plate 1 comprises upper and lower sliding portions 1A, 1B inserted in the upper and lower guides 3, 5, respectively, and a shield portion 1C coupling the upper and lower sliding portions 1A, 1B and shielding the radiation beam. The shield portions 1C of every two adjacent leaf plates 1 are arranged to be able to slide in a close contact relation. To that end, the upper and lower sliding portions 1A, 1B are each formed to have a smaller thickness than the shield portion 1C for securing spaces necessary for installing the upper and lower guides 3, 5. Also, to that end, the upper and lower guides 3, 5 and the upper and lower air cylinders 2, 4 associated with the adjacent leaf plates 1 are arranged in an alternately displaced relation (in a zigzag pattern), as shown in FIGS. 1, 5 and 6. A rack gear 12 is partly provided on an upper edge of the lower sliding portion 1B of each leaf plate 1 in the leaf plate driver 200L. The aforesaid pinion gear 6 is arranged in a position where it is able to engage (mesh) with the rack gear 12. On the other hand, the aforesaid braking plate 9 is disposed opposite to a lower edge of the upper sliding portion 1A of each leaf plate 1 in the leaf plate driver 200L. When moving the leaf plate 1, the lower air cylinder 4 is set to the operative condition and the upper air cylinder 2 is set to the inoperative (stop) condition, whereupon the leaf plate 1 is moved upward to mesh the rack gear 12 with the pinion gear 6, while the lower edge of the upper sliding portion 1A is moved away (disengaged) from an upper surface of the braking plate 9. By operating the motor 8 in such a state, the leaf plate 1 can slide in the predetermined direction through transmission of the driving force of the motor 8. Then, when stropping the leaf plate 1, the motor 8 is first stopped to cease the movement of the leaf plate 1. After that, by setting the upper air cylinder 2 to the operative condition and the lower air cylinder 4 to the inoperative condition, the leaf plate 1 is moved downward to release the rack gear 12 from mesh with the pinion gear 6, while the lower edge of the upper sliding portion 1A is partly brought into abutment against the upper surface of the braking plate 9. The leaf plate 1 is thereby positively held stationary at that position. Likewise, in the leaf plate driver 200R, a rack gear 12 is partly provided on a lower edge of the upper sliding portion 1A of each leaf plate 1, and the aforesaid braking plate 9 is disposed opposite to an upper edge of the lower sliding portion 1B. By setting the upper air cylinder 2 to the operative condition, the leaf plate 1 is moved downward to mesh the rack gear 12 with the pinion gear 6 so that the leaf plate 1 slides by the driving force of the motor 8, while the upper edge of the lower sliding portion 1B is moved away from a lower surface of the braking plate 9. Also, by setting the lower air cylinder 4 to the operative condition, the leaf plate 1 is moved upward to release the rack gear 12 from mesh with the pinion gear 6, while the upper edge of the lower sliding portion 1B is partly brought into abutment against the lower surface of the braking plate 9. The leaf plate 1 is thereby positively held stationary at that position. An upper coupling portion 201a, a lower coupling portion 201b, and an intermediate coupling portion 201c (see FIGS. 5 and 6) are disposed respectively between the upper supports 7a, between the lower supports 7b, and between the intermediate supports 7c of the leaf plate driving body 200L, 200R for coupling them. Of those coupling portions, the upper and lower coupling portions 201a, 201b have cutouts 202 formed therein to allow passage of the radiation beam. (4) Control System (4-1) Overall Construction FIG. 7 is a functional block diagram showing a system configuration of a control system in a medical system including the multi-leaf collimator 200 of this embodiment. In addition to the remedy scheduling unit 24, the control unit 23 and the collimator controller 22 mentioned above, the control system further comprises a leaf position driving actuator 14 (servo motor 8 in this embodiment) controlled in accordance with a rotation driving command and a driving stop command from the collimator controller 22; a driving force transmitting/cutoff mechanism 15 (upper and lower air cylinders in this embodiment) controlled in accordance with a driving force transmitting command and a driving force cutoff command from the collimator controller 22; a braking force transmitting/cutoff mechanism 16 (upper and lower air cylinders in this embodiment, described later in detail) controlled in accordance with a braking force transmitting command and a braking force cutoff command from the collimator controller 22; and a position detecting mechanism 19 (servo motor 8 in this embodiment, described later in detail) for outputting a position detected signal for each leaf plate 1 to the collimator controller 22. It is to be noted that, as described above, this embodiment is arranged to transmit or cut off the driving force from the pinion gear 6 and to cut off or transmit the braking force from the braking plate 9 at the same time, and switching between transmission and cut off of the driving force or the braking force is performed by the upper and lower air cylinders cylinders 2, 4. Consequently, the driving force transmitting/cutoff mechanism 15 and the braking force transmitting/cutoff mechanism 16 are constituted by a common mechanism. Further, the driving force transmitting command serves also as the braking force cutoff command, and the driving force cutoff command serves also as the braking force transmitting command. (4-2) Remedy Scheduling Unit 24 The remedy scheduling unit 24 comprises, for example, a computer, a plurality of display devices, an input device, and a patient database (the patient database may be separately prepared and connected to the unit 24 via a network). The remedy scheduling unit 24 has the function of aiding the remedy scheduling work to be made by a doctor as a pre-stage for carrying out actual irradiation. Practical examples of the remedy scheduling work include identification of the diseased part, decision of the irradiation area and the irradiating directions, decision of the radiation dose irradiated to the patient, and calculation of a dose distribution in the patient body. (A) Identification of Diseased Part In a diagnosis prior to the remedy, for example, three-dimensional image data of a tumor in the patient body is taken beforehand by an X-ray CT inspection and an MRI inspection. Those inspection data is given with a number for each patient, and is stored and managed as digital data in the patient database. In addition to the inspection data, the patient database also contains information such as the name of patient, the patient number, the age, height and weight of patient, the diagnosis and inspection records, historical data for diseases that the patient has suffered, historical data for remedies that the patient has taken, and remedy data. Stated otherwise, all data necessary for remedy of the patient is recorded and managed in the patient database. The doctor can access the patient database, as required, to acquire the image data of the diseased part and display the image data on the display devices of the remedy scheduling unit 24. Specifically, it is possible to display the image data of the diseased part as a three-dimensional image looking from any desired direction, and as a sectional image sliced at each of different depths looking from any desired direction. Further, the remedy scheduling unit 24 has the functions of assisting the doctor to identify the diseased part, such as contrast highlighting and area painting-out with a certain gradation level as a threshold for each image. The doctor identifies an area of the diseased part by utilizing those assistant functions. (B) Tentative Selection of Irradiation Area and Irradiating Directions Subsequently, the doctor makes an operation to decide the irradiation area that envelops the diseased part and includes an appropriate margin in consideration of a possibility that the diseased part may move in the patient body due to breathing, for example. Further, the doctor selects several irradiating directions out of interference with the internal organs highly susceptible to radiation, such as the spine. (C) Decision of Contour of Irradiation Field Based on the several irradiating directions, an image of the irradiation field looking from each irradiating direction is displayed, and the contour of the irradiation field covering the whole of a tumor is displayed in a highlighted manner. Also, a three-dimensional image of the diseased part is displayed, and a position of a maximum section and a three-dimensional shape subsequent to the maximum section are displayed. Those images are displayed on a plurality of display screens separately, or on one display screen in a divided fashion. Herein, the contour of the irradiation field decided provides basic (original) data for the irradiation field F shaped by the multi-leaf collimator 200, and the three-dimensional shape data subsequent to the maximum section provides basic (original) data for irradiation compensators, such as the porous members 206A, 206B. (D) Decision of Irradiating Direction and Radiation Dose Irradiated to Patient The remedy scheduling unit 24 has the function of automatically deciding a position of each leaf plate 1 of the multi-leaf collimator 200 based on information regarding the contour of the irradiation field, and can display the automatically decided position of each leaf plate 1 and an image of the maximum section of the irradiation field in a superimposed relation. At this time, the doctor can provide an instruction to finely change and adjust the position of each leaf plate 1 with reference to the superimposed images, or the position of each leaf plate 1 can be decided in response to an operation instruction provided by the doctor while the superimposed images are displayed. The decision result of the position of each leaf plate 1 is promptly reflected in the display on the display device. Based on both the leaf-plate set position information and the irradiation compensator information, the remedy scheduling unit 24 simulates a radiation dose distribution in the patient body and displays a calculation result of the dose distribution on the display device. On that occasion, irradiation parameters such as the radiation dose irradiated to the patient and the radiation energy are given by the doctor, and the simulation is performed for each of the selected several irradiating directions. The doctor finally selects the irradiating direction in which the most preferable result was obtained. The selected irradiating direction and the associated set position information for the leaf plates 1 of the multi-leaf collimator 200, irradiation compensator data, and irradiation parameters are stored in the patient database as remedy data specific to the patient. (4-2) Control Unit 23 and Collimator Controller 22 The control unit 23 comprises an input device and a display device, which serve as a user operation interface. Also, the control unit 23 is able to acquire the patient remedy data, including the set position information for the leaf plates 1 decided in the remedy scheduling unit 24, via network connection from the patient database associated with the remedy scheduling unit 24, and to display the acquired data on the display device for confirmation by the doctor, etc. Then, in practical irradiation, when a user of the set position information for the leaf plates 1 (a doctor or a radiotherapeutic engineer engaged in assisting the doctor""s remedy based on the remedy schedule), for example, inputs the start of irradiation remedy, the control unit 23 outputs a command for starting movement of the leaf plates to the collimator controller 22 in accordance with the set position information for the leaf plates 1. In response to the command from the control unit 23, the collimator controller 22 outputs necessary control commands to respective subordinating mechanisms, i.e., the leaf position driving actuator 14, the driving force transmitting/cutoff mechanism 15, and the braking force transmitting/cutoff mechanism 16. Upon receiving the movement start command, the collimator controller 22 controls those subordinating mechanisms so that each leaf plate 1 is moved to the predetermined set position. (4-3) Control of Leaf Plate Movement to Set Position The procedures for moving each leaf plate 1 by the collimator controller 22 will first be described with reference to FIG. 8 showing a control flow in this case. Referring to FIG. 8, the control flow begins when the collimator controller 22 receives the movement start command from the control unit 23. Note that this flow proceeds in parallel for each of the leaf plate driving body 200L, 200R concurrently. First, in step 10, the collimator controller 22 receives the set position information for each leaf plate 1 from the control unit 23 and stores it in a storage means (not shown). Then, in step 20, the driving force transmitting command (which serves also as the braking force cutoff command as described above) for transmitting the driving force to all the leaf plates 1 of the leaf plate driver 200L (or 200R) is outputted to the driving force transmitting/-cutoff mechanism 15 (all the upper and lower air cylinders 2, 4 in this embodiment). With this step, in the leaf plate driver 200L, the upper air cylinders 3 and the lower air cylinders 4 associated with all the leaf plates 1 are brought respectively into the inoperative condition and the operative condition (in the leaf plate driver 200R, the upper air cylinders 3 and the lower air cylinders 4 associated with all the leaf plates 1 are brought respectively into the operative condition and the inoperative condition). Thus, all the leaf plates 1 associated with the leaf plate driver 200L (or 200R) are moved away from the braking plate 9 and are meshed with the pinion gear 6. Next, in step 30, the collimator controller 22 outputs, to the leaf position driving actuator 14 (servo motor 8 in this embodiment), a rotation driving command (leaf advance command) to rotate the motor 8 in the leaf advancing direction (=inserting direction, i.e., direction to narrow the space gap G corresponding to the irradiation field F). Responsively, the motor 8 of the leaf plate driver 200L (or 200R) starts rotation, whereupon all the leaf plates 1 start moving forward in the inserting direction in a transversely aligned state. Then, in step 40, an amount of insertion (current position) of each leaf plate 1 is detected. Specifically, the collimator controller 22 receives a rotation signal (aforesaid pulse signal) outputted from the servo motor 8 which serves as the position detecting mechanism 19, and determines a rotation angle of the pinion gear 6 from the rotation signal. Further, the collimator controller 22 determines an amount of movement of each leaf plate 1 from both the rotation angle and a gear ratio of a rack-and-pinion mechanism comprising the pinion gear 6 and the rack gear 12, and totalizes the amount of movement from the origin, thereby obtaining current position information for each leaf plate 1. Subsequently, the control flow proceeds to step 50 where it is determined whether any of all the leaf plates 1 has reached the set position of the relevant leaf plate 1, which is defined by the leaf-plate set position information stored in the collimator controller 22. If not so, the control flow returns to step 20 for repeating the above-described steps in the same manner, and if so, the control flow proceeds to step 60. In step 60, the collimator controller 22 outputs a driving stop command (leaf stop command) to the leaf position driving actuator 14 (servo motor 8 in this embodiment). In accordance with that command, the rotation of the motor 8 is stopped and the movements of all the leaf plates 1 are stopped simultaneously. Thereafter, in step 70, the driving force cutoff command (which serves also as the braking force transmitting command as described above) is outputted to the driving force transmitting/cutoff mechanism 15 (upper and lower air cylinders 2, 4) associated with the leaf plate 1 that has reached the set position. With this step, in the leaf plate driver 200L, the lower air cylinder 4 and the upper air cylinder 3 associated with the relevant leaf plate 1 are brought respectively into the inoperative condition and the operative condition (in the leaf plate driver 200R, the lower air cylinder 4 and the upper air cylinder 3 associated with the relevant leaf plate 1 are brought respectively into the operative condition and the inoperative condition). Thus, the relevant leaf plate 1 is out of mesh with (disengaged from) the pinion gear 6, moves away (departs) from it, and is brought into contact with the braking plate 9. As a result, the relevant leaf plate 1 is held stationary at the set position with stability. Then, in step 80, it is determined whether all the leaf plates 1 associated with the leaf plate driver 200L (or 200R) have reached the set positions. If not so, the control flow returns to step 20 for repeating the above-described steps in the same manner until all the leaf plates 1 reach the set positions. More specifically, in step 20, the rotation of the motor 8 is started again, whereby all of the remaining leaf plates 1 start moving forward again while leaving the leaf plate 1 at the set position, which has reached there in above step 70. Then, through steps 20 to 70, the operations of stopping all the remaining leaf plates 1 upon one leaf plate 1 reaching the set position, cutting off the driving force (making disengagement) and transmitting the braking force for only the relevant one leaf plate 1, transmitting the driving force (making engagement) again and releasing the braking force again for the remaining leaf plates 1, and resuming insertion of the remaining leaf plates 1 are repeated until all the leaf plates 1 are completely moved to the set positions and the driving force is cut off for all the leaf plates 1. When all the leaf plates 1 have reached the set positions and the driving force is cut off for all the leaf plates 1, the determination in step 80 is satisfied and the collimator controller 22 outputs a leaf-plate insertion end signal to the control unit 23 in step 90, thereby completing the control flow. In the above-described steps, the current position information and the driving status of each leaf plate 1 under management of the collimator controller 22 are always transmitted to the control unit 23 and displayed on the display device of the control unit 23. (4-4) Return Control of Leaf Plate to Origin Position When the leaf plates have all been positioned to the set positions as described above and then irradiation of a radiation beam is ended, the control unit 23 outputs a leaf-plate return-to-origin command to the collimator controller 22 upon the end of irradiation remedy being instructed from the user of the set position information for the leaf plates 1. Upon receiving the return-to-origin command from the control unit 23, the collimator controller 22 controls the aforesaid subordinating mechanisms to move each leaf plate 1 for return to the origin position in a similar but reversed manner to that described above in (4-3). The procedures for returning each leaf plate 1 to the origin by the collimator controller 22 will be described with reference to FIG. 9 showing a control flow in this case. Referring to FIG. 9, the control flow begins when the collimator controller 22 receives the return-to-origin command from the control unit 23. Note that, similarly to the flow of FIG. 8, this flow also proceeds in parallel for each of the leaf plate driving body 200L, 200R concurrently. First, in step 110, the driving force transmitting command (which serves also as the braking force cutoff command) for transmitting the driving force to all the leaf plates 1 of the leaf plate driver 200L (or 200R) is outputted to the driving force transmitting/cutoff mechanism 15 (upper and lower air cylinders 2, 4). With this step, in the leaf plate driver 200L, the upper air cylinders 3 and the lower air cylinders 4 associated with all the leaf plates 1 are brought respectively into the inoperative condition and the operative condition (in the leaf plate driver 200R, the upper air cylinders 3 and the lower air cylinders 4 associated with all the leaf plates 1 are brought respectively into the operative condition and the inoperative condition). Thus, all the leaf plates 1 associated with the leaf plate driver 200L (or 200R) are moved away from the braking plate 9 and are meshed with the pinion gear 6. Next, in step 120, the collimator controller 22 outputs, to the leaf position driving actuator 14 (servo motor 8 in this embodiment), a rotation driving command (leaf retreat command) to rotate the motor 8 in the leaf retreating direction (=withdrawing direction, i.e., direction to widen the aforesaid space gap G). Responsively, the motor 8 of the leaf plate driver 200L (or 200R) starts rotation, whereupon all the leaf plates 1 start moving backward in the withdrawing direction in a transversely not-aligned state (position difference among the leaf plates 1 remain the same). Then, in step 130, an amount of withdrawal (current position) of each leaf plate 1 is detected. Specifically, as with the above case, the collimator controller 22 determines an amount of movement of each leaf plate 1 from a rotation signal outputted from the servo motor 8 which serves as the position detecting mechanism 19, and obtains current position information for each leaf plate 1 based on the determined amount of movement. In step 140, it is determined whether any of all the leaf plates 1 has reached the origin position. If not so, the control flow returns to step 120 for repeating the above-described steps in the same manner, and if so, the control flow proceeds to step 150. In step 150, the collimator controller 22 outputs a driving stop command (leaf stop command) to the leaf position driving actuator 14 (motor 8). In accordance with that command, the rotation of the motor 8 is stopped and the movements of all the leaf plates 1 are stopped simultaneously while they remain in the transversely not-aligned state. Instead of above steps 130 to 150, this embodiment may be modified such that, for example, a limit switch (not shown) is provided beforehand in the vicinity of the origin at a certain distance, and when one leaf plate 1 is withdrawn to a position near the origin and contacts the limit switch, a signal indicating the arrival of the relevant leaf plate 1 to the position near the origin is outputted from the limit switch to the collimator controller 22. In such a modified case, for example, at the timing at which the relevant leaf plate 1 is further withdrawn and an amount of withdrawal of the relevant leaf plate 1 from the time having received the above signal becomes equal to the distance from the limit switch to the origin, the driving stop command is outputted to the motor 8 so as to stop the movements of all the leaf plates 1 simultaneously. Thereafter, the control flow proceeds to step 160 where the driving force cutoff command (which serves also as the braking force transmitting command) is outputted to the driving force transmitting/cutoff mechanism 15 (upper and lower air cylinders 2, 4) associated with the leaf plate 1 that has reached the origin position. With this step, in the leaf plate driver 200L, the lower air cylinder 4 and the upper air cylinder 3 associated with the relevant leaf plate 1 are brought respectively into the inoperative condition and the operative condition (in the leaf plate driver 200R, the lower air cylinder 4 and the upper air cylinder 3 associated with the relevant leaf plate 1 are brought respectively into the operative condition and the inoperative condition). Thus, the relevant leaf plate 1 is out of mesh with (disengaged from) the pinion gear 6, moved away (departs) from it, and is brought into contact with the braking plate 9. As a result, the relevant leaf plate 1 is completely returned to the origin position and is held stationary there with stability. Then, in step 170, it is determined whether all the leaf plates 1 associated with the leaf plate driver 200L (or 200R) have returned to the origin positions. If not so, the control flow returns to step 110 for repeating the above-described steps in the same manner until all the leaf plates 1 return to the origin positions. More specifically, in step 110, the rotation of the motor 8 is started again, whereby all of the remaining leaf plates 1 are withdrawn again in the retreating direction while they remain in the transversely not-aligned state. Then, through steps 110 to 170, the operations of stopping all the remaining leaf plates 1 upon one leaf plate 1 returning to the origin position, cutting off the driving force (making disengagement) and transmitting the braking force for only the relevant one leaf plate 1, transmitting the driving force (making engagement) again and releasing the braking force again for the remaining leaf plates 1, and resuming withdrawal of the remaining leaf plates 1 are repeated until all the leaf plates 1 are completely returned to the origin positions and the driving force is cut off for all the leaf plates 1. When all the leaf plates 1 have returned to the origin positions and the driving force is cut off for all the leaf plates 1, the determination in step 170 is satisfied and the collimator controller 22 outputs a leaf-plate return-to-origin end signal to the control unit 23 in step 180, thereby completing the control flow. In the above-described steps, the current position information and the driving status of each leaf plate 1 under management of the collimator controller 22 are always transmitted to the control unit 23 and displayed on the display device of the control unit 23. In the foregoing description, the servo motor 8 in each of the leaf plate driving body 200L, 200R constitutes one driving means defined in Claim 1, and the pinion gear 6, all the upper and lower air cylinders 2, 4, and all the upper and lower guides 3, 5 cooperatively constitute driving force transmitting means that is capable of transmitting the driving force to a plurality of leaf plates at the same time and cutting off the driving force selectively for each leaf plate. Also, the servo motor 8 and the pinion gear 6 in each of the leaf plate driving body 200L, 200R constitutes one driving force generating means defined in Claim 2, which is provided to be capable of transmitting the driving force to the plurality of leaf plates at the same time. A pair of upper and lower air cylinders 2, 4 and a pair of upper and lower guides 3, 5, which are provided for each leaf plate 1, cooperatively constitute a plurality of engaging/disengaging means that are provided in a one-to-one relation to the plurality of leaf plates and are each capable of selectively engaging and disengaging a corresponding leaf plate with or from the one driving force generating means. Further, the braking plate 9 constitutes holding means capable of abutting against the leaf plates to hold the leaf plates in predetermined positions. Moreover, the collimator controller 22 constitutes control means, defined in Claim 8, for controlling the one driving means and the driving force transmitting means, and constitutes control means, defined in Claim 9, for controlling the one driving force generating means and the engaging/disengaging means. (5) Advantages of This Embodiment With the multi-leaf collimator of this embodiment, as described above (particularly in (3) and (4)), in each of the leaf plate driving body 200L and 200R, the driving force of the one common motor 8 can be transmitted to a plurality of leaf plates 1 at the same time, and the driving force can be selectively cut off for each leaf plate 1. When driving each leaf plate 1 from the origin position to the set position, the driving force is transmitted to the plurality of leaf plates 1 at the same time, causing all the leaf plates 1 to start movement simultaneously. Then, when one leaf plate 1 reaches the set position, the driving force applied to the relevant leaf plate 1 is cut off to leave it at the set position. By repeating such a step, all the leaf plates 1 are successively positioned to the set positions. Conversely, when returning all the leaf plates 1 to the origin positions from the set condition, the driving force is transmitted to all the leaf plates 1 in the different set positions at the same time, causing all the leaf plates 1 to start movement simultaneously while they remain in the transversely not-aligned state. Then, when one leaf plate 1 returns to the origin position, the driving force applied to the relevant leaf plate 1 is cut off to hold it at the origin position. By repeating such a step, all the leaf plates 1 are successively returned to the origin positions. Thus, since the leaf plates 1 can be successively positioned in each of the leaf plate driving body 200L and 200R while moving a plurality of leaf plates at the same time, a time required for completing the formation of the irradiation field, when the irradiation field is to be formed with high accuracy, can be shortened in comparison with a conventional structure wherein a number of leaf plates must be positioned one by one successively in each leaf plate driver. As a result, physical and mental burdens imposed on patients can be reduced. A second embodiment of the present invention will be described with reference to FIGS. 10 to 12. In this embodiment, the support structure of each leaf plate 1 is modified, and the driving force transmitting/cutoff mechanism 15 and the braking force transmitting/cutoff mechanism 16 are separately provided. The same components as those in the first embodiment are denoted by the same reference numerals, and a description of those components is omitted herein. FIG. 10 is a perspective view showing the structure of principal parts of a leaf plate driver 200R provided in a multi-leaf collimator of this embodiment. For the sake of simplicity, only three of total twelve leaf plates 1 are shown in FIG. 10. FIG. 11 is a front view as viewed in the direction of C in FIG. 10, and FIG. 12 is a perspective view showing the detailed structure of one leaf plate 1 in FIGS. 10 and 11. Referring to FIGS. 10, 11 and 12, in the leaf plate driver 200R provided in the multi-leaf collimator of this embodiment, a vertical position of each leaf plate 1 is always held constant. More specifically, an upper end 1a and a lower end 1b of each leaf plate 1 are contacted with respective rollers 26 rotatably provided on an upper projection 25A and a lower bottom plate 25B of a housing 25. Also, a lower edge of an upper sliding portion 1A and an upper edge of a lower sliding portion 1B of each leaf plate 1 are contacted with respective rollers 26 rotatably provided on upper and lower surfaces of an intermediate projection 25C of the housing 25. With such a structure, the leaf plate 1 is able to slide in the longitudinal direction thereof (left and right direction in FIG. 11) while its vertical displacement is restricted by the rollers 26. On the other hand, a position of each leaf plate 1 in the thickness direction thereof is maintained with such an arrangement that all the leaf plates 1 are sandwiched between a pressing mechanism 28 vertically provided on the housing lower bottom plate 25B and a housing body 25d disposed to extend in the vertical direction. More specifically, the pressing mechanism 28 includes a rotatable roller 28A, which is contacted with one of the total twelve leaf plates 1 positioned closest to the pressing mechanism 28. Though not shown, the housing body 25d also includes a rotatable roller, similar to the roller 28A, which is contacted with one of the twelve leaf plates 1 positioned closest to the housing body 25d. Thus, outermost two of the total twelve leaf plates 1 in the thickness direction thereof are restricted by the rollers from both sides, whereby the total twelve leaf plates 1 are each restricted from displacing in the thickness direction. On both lateral surfaces of the upper sliding portion 1A and the lower sliding portion 1B of each leaf plate 1, frictional sliding members 35A, 35B are provided in contact with the adjacent leaf plates 1. Since the pressing mechanism 28 applies a load for pressing all the leaf plates 1 toward the housing body 25d, the leaf plates 1 are held in a condition contacting with each other at the frictional sliding members 35A, 35B. The pressing load applied to the leaf plates 1 from the pressing mechanism 28 is adjusted such that the leaf plates 1 are slidable individually. A rack gear 12 is disposed at the top of the upper sliding portion 1A of each leaf plate through an air-cushion mechanism 31. A pinion gear 6 connected to the motor 8 is provided in an opposing relation to the rack gear 12 of each leaf plate 1. When compressed air is introduced to the air-cushion mechanism 31 through a piping system (not shown) and the air-cushion mechanism 31 is vertically expanded (=in operative condition), the rack gear 12 is raised up into mesh with the pinion gear 6 for transmitting the driving force. When the compressed air is discharged through a piping system (not shown), the air-cushion mechanism 31 is contracted and the rack gear 12 is out of mesh with the pinion gear 6, thereby disabling (cutting off) the transmission of the driving force. Stated otherwise, the air-cushion mechanism 31 provided for each leaf plate 1 fulfills the function of the driving force transmitting/-cutoff mechanism 15 described above in the first embodiment with reference to FIG. 7. Further, in this embodiment, an air cylinder 34 for moving a braking plate 9 up and down serves as the braking force transmitting/cutoff mechanism 16 shown in FIG. 7. More specifically, the air cylinder 34 is provided on the backside (underside) of the housing bottom plate 25B in a one-to-one relation to the leaf plates 1, and has a rod 34a penetrating the housing bottom plate 25B to project upward. The braking plate 9 is connected to a fore end of the rod 34a. As with the air cylinders 2, 4 used in the first embodiment of the present invention, the air cylinder 34 is constituted by a known single- or double-actuated air cylinder. When compressed air is supplied from a compressed air source to a bottom-side chamber, the rod 34a is extended (operative condition), the braking plate 9 is raised upward to such an extent that an upper surface of the braking plate 9 abuts against the leaf plate lower end 1b to produce braking force. The leaf plate 1 is hence stopped and held at that position by frictional force. Subsequently, when the compressed air supplied to the bottom-side chamber is discharged (for example, by being made open to the atmosphere), a piston is returned to the bottom side by the biasing force of a spring. As a result, the rod 34a is contracted (inoperative or stop condition) for return to the original position so that the leaf plate is made free (released) from the braking force. Thus, in this embodiment, the air cylinder 34 provided for each leaf plate 1 serves as the braking force transmitting/cutoff mechanism 16 described above in connection with FIG. 7. Additionally, the braking plate 9 comes into contact with the leaf plate 1 and generates frictional braking force only when the air cylinder 34 is operated to raise the braking plate 9 upward. While the above description is made in connection with, for example, the leaf plate driver 200R on one side, the leaf plate driver 200L on the other side is of the same structure. Control procedures for driving the leaf plates 1 in this embodiment having the above-mentioned construction are basically the same as those in the first embodiment described above with reference to FIGS. 8 and 9 except that the transmission/cutoff of the driving force and the transmission/cutoff of the braking force are separately controlled. More specifically, the procedures for moving the leaf plates 1 to the set positions, described above in connection with FIG. 8, and the procedures for returning the leaf plates 1 to the origin positions, described above in connection with FIG. 9, are modified as follows. In steps 20 and 110, a driving force transmitting command for transmitting the driving force to the leaf plates 1 is outputted to the air-cushion mechanism 31 that serves as the driving force transmitting/cutoff mechanism 15, and a braking force cutoff command is outputted to the air cylinder 34 that serves as the braking force transmitting/Attorney mechanism 16. In accordance with those commands, the air-cushion mechanism 31 is brought into the operative condition and the air cylinder 34 is brought into the inoperative condition, respectively, whereby the braking plate 9 departs away from the leaf plate 1 and the pinion gear 6 meshes with the rack gear 12. Also, in steps 70 and 160, a driving force cutoff command for cutting off the driving force applied to the leaf plates 1 is outputted to the air-cushion mechanism 31, and a braking force transmitting command is outputted to the air cylinder 34. In accordance with those commands, the air-cushion mechanism 31 is brought into the inoperative condition and the air cylinder 34 is brought into the operative condition, respectively, whereby the braking plate 9 contacts with the leaf plate 1 and the pinion gear 6 is out of mesh with the rack gear 12. In the foregoing description, the pinion gear 6 and all the air-cushion mechanisms 31 in each of the leaf plate driving body 200L, 200R cooperatively constitute driving force transmitting means defined in Claim 1, which is capable of transmitting the driving force to a plurality of leaf plates at the same time and cutting off the driving force selectively for each leaf plate. Also, the air-cushion mechanisms 31 provided in each of the leaf plate driving body 200L, 200R in a one-to-one relation to the leaf plates 1 constitute a plurality of engaging/-disengaging means that are provided in a one-to-one relation to the plurality of leaf plates and are each capable of selectively engaging and disengaging a corresponding leaf plate with or from the one driving force generating means. This embodiment can also provide similar advantages as those in the first embodiment of the present invention. While the driving force is transmitted in the first and second embodiments through meshing of the pinion gear 6 with the rack gear 12, the present invention is not limited to such an arrangement. For example, the arrangement may be modified such that a rubber roller having a cylindrical shape is provided instead of the pinion gear 6, the upper and lower edges of the upper and lower sliding portions 1A, 1B of each leaf plate 1 are each formed in an ordinary shape without the rack gear 12, and the rubber roller is brought into engagement with the upper and lower edges of the upper and lower sliding portions 1A, 1B for transmitting the driving force through frictional force produced upon the engagement. This modification can also provide similar advantages. Further, in the first and second embodiments, the upper and lower air cylinders 2, 4 or the air cylinders 34 are used as the driving force transmitting/cutoff mechanism 15 or the braking force transmitting/cutoff mechanism 16. Instead of those cylinders, however, known linearly reciprocating actuators provided with solenoid magnets (electromagnets) may be used. This modification can also provide similar advantages. While the first and second embodiments employ the servo motor 8 as the leaf position driving actuator 14, a stepping motor may be used instead. A stepping motor is a motor that rotates through a minute angle for each pulse when a pulse-shaped signal is applied as a drive signal to the motor. Usually, a rotation angle per pulse of the drive signal is reliably provided with high accuracy. In this modification, the drive signal for driving the stepping motor can be used instead of the rotation signal obtained from the servo motor 8 in the first and second embodiments. This modification can also provide similar advantages. In the first and second embodiments, the servo motor 8 functions also as the position detecting mechanism 19. However, the present invention is not limited to such an arrangement, and the position detecting mechanism 19 may be constituted by a linear encoder separately provided. A linear encoder comprises, for example, a rotary encoder, a wire, and a winding reel. The reel is rotated corresponding to the distance through which the wire is drawn out, and the rotary encoder connected to the reel generates a rotation signal. In this modification, the linear encoder is provided in the same number as the leaf plates 1 because it is connected to each leaf plate 1 in a one-to-one relation. Then, each linear encoder always outputs, to the collimator controller 22, pulse signals corresponding to the distance of movement of the leaf plate 1 connected to that linear encoder. Based on the known relationship between the pulse signal and the distance of movement of the leaf plate, the collimator controller 22 adds up the distance of movement of each leaf plate 1 and stores it therein as the position information. Furthermore, instead of the linear encoder, another type of linear displacement detector may be connected to each leaf plate 1. Other types of linear displacement detector include, for example, a linear scale, a linear potentiometer, and an LVDT (Linear Variable Differential Transformer). A linear scale comprises a linear rule and a reading head. The reading head moving over the linear rule optically or magnetically reads position symbols disposed on the rule with minute intervals, and outputs a pulse signal. A position detecting method based on a pulse signal is the same as the case described above. A linear potentiometer comprises a linear resistor and a slider linearly moving in slide contact with the resistor. Based on the fact that a resistance value between a terminal connected to one end the resistor and a terminal connected to the slider is given by a resistance value corresponding to the length of the resistor from the resistor terminal to the slider position, the resistance value is linearly changed depending on the distance through which the slider has moved. By connecting a power supply between both the terminals and measuring a voltage therebetween, the resistance value is read after transformation into voltage. In this case, the collimator controller 22 reads the voltage through an A/D converter and calculates the amount of movement of the slider (leaf plate) based on both the relationship between resistance value and voltage in a resistancexe2x80x94voltage converter and the linear relationship between displacement and resistance value, which is specific to the linear potentiometer. An LVDT comprises a unit made up of an excited primary coil and a secondary coil which are coaxially arranged side by side, and an iron core arranged to lie at the centers of the primary coil and the secondary coil and to extend in a straddling relation to both the coils. A linear displacement of the iron core connected to a measurement target is outputted as a change in an output voltage of the secondary coil, which is produced as the strength of coupling between the primary coil and the secondary coil changes. Design parameters are set such that the relationship between displacement and output voltage is linear and provides a constant gradient. Manners for reading the voltage and calculating the displacement are similar to those in the above case. According to the present invention, as described above, it is possible to shorten a positioning time required for forming an irradiation area with high accuracy using a number of leaf plates, and to reduce physical and mental burdens imposed on patients.
	description	This is a continuation of application Ser. No. 11/798,395 filed 14 May 2007, now U.S. Pat. No. 7,435,959 which is a continuation of application Ser. No. 11/197,584 filed 8 Aug. 2005, U.S. Pat. No. 7,217,923 B2, which is a continuation of application Ser. No. 10/857,956 filed 2 Jun. 2004, U.S. Pat. No. 6,936,819 B2, which is a continuation of application Ser. No. 10/389,882 filed 18 Mar. 2003, U.S. Pat. No. 6,765,204, which is a continuation of application Ser. No. 09/684,469 filed 6 Oct. 2000, U.S. Pat. No. 6,573,499. The present invention relates to microstructured pattern inspection method, particularly, to a method of inspecting the microstructured patterns, such as contact holes and linear patterns, that are formed on semiconductor wafers with the photolithography that uses an optical exposure apparatus such as a stepper. In the manufacture of semiconductors, photolithography is used to form patterns on semiconductor wafers. The formation of these patterns most commonly uses the reduction projection alignment method that applies an apparatus in which a reticle formed by enlarging the circuit patterns for several chips is used for reduction projection alignment (hereinafter, this apparatus is referred to as the stepper). In the reduction projection alignment method using the stepper, a reduced image of the mask pattern of the reticle is exposed to light so as to be projected and formed on the photoresist coating of the wafer, with the result that a resist pattern, a copy of the reticle mask pattern, is formed on that wafer by processing chemically the photosensitized photoresist coating. The patterns for several chips that have been formed on the reticle can be copied with a single shot (exposure). This procedure is “stepped and repeated” to copy more such patterns on the wafer. An example of forming contact holes on the insulating film of the wafer is described below. First, a photoresist coating is formed on the insulating film. Next, the photoresist coating undergoes exposure using a reticle provided with a pattern of contact holes of the design size and arrangement, and then undergoes chemical processing. After this, contact hole patterns passing through the insulating film can be formed on the wafer by performing processes such as etching, and in this etching process, the photoresist coating that has been created by copying the required pattern functions as a mask. To ensure that the stepper forms patterns on the wafer as described above, the microstructured patterns on the dimensionally enlarged reticle must undergo reduction projection alignment on the wafer through projection optics. The surface and bottom of the exposed layer (photoresist coating) of the patterns that have been exposed to light in the reduction projection alignment process occasionally differ in size, shape, position, and other factors. The first main cause of these differences is a combination of defects in the wafer material and defects in the workmanship of the substance exposed to light on the wafer, such as a resist. The warping, distortion, deflection, and the like, of the wafer itself can occur during its manufacture or according to the subsequent elapse of time or the particular ambient environmental conditions such as temperature, and these defects affect optical interference. The shapes of the patterns formed will also be affected by the nature of the substance to be used as a resist, and by the resist coating thickness, coating status, and other factors. Such deviations (from design specifications) in terms of the forming positions and dimensions at the exposed surface and bottom of the microstructured patterns due to the characteristics of the exposed substance (hereinafter, these deviations are collectively called “dislocations”) are usually distributed over a wide range in a specific area of the wafer, and with a fixed tendency. The second main cause is such insufficiency in the performance of the optics used in the stepper as schematized in FIG. 2. As shown in FIG. 2(a), no problems occur in the vicinity of the reticle center. As shown in FIG. 2(b), however, if light is emitted obliquely to the surface of the wafer, lens aberration, such as astigmatism or comatic aberration, will occur at the edges of the reticle. Dislocation due to such aberration mainly appears within a single-shot area, radially from its central position and with a fixed tendency. The third main cause is a defect in the nature of the optics of the stepper, that is to say, a shift in focal position (defocusing), which arises from the fact that the lenses in the optics used for exposure suffer deformation due to the heat generated during exposure (this event is called “lens heating”). The fourth main cause is a defect in the performance of the optics of the stepper. If the optics of the stepper has any inclined parts such as lens, since the emitted light enters laterally, the exposure pattern within a single-shot area skews in a fixed direction. Differences between the design specifications and actually formed patterns are mainly caused by the four factors described above. The first problem resulting from these differences is that dislocation occurs between the patterns that were formed on the surface and bottom of the photoresist. Similarly, there also occurs misalignment with respect to the pattern in the lower layer or upper layer of the insulator, due to the axial and position offsets between the design specifications and actually exposed patterns. Axial or position offsets in contact hole patterns reduce the area of the hole, thus increasing electrical resistance, and finally leading to deteriorated semiconductor performance. In some cases, the semiconductor loses electroconductivity, which is a critical defect in the semiconductor device itself. With respect to these problems, at present, exposure accuracy at the bottom area of the microstructured patterns is usually evaluated by calculating the area of the bottom. However, there is no established method for evaluating quantitatively the optics of the stepper, the wafer, or the like, from the quantity or direction of pattern dislocation or from these factors. The present invention is therefore intended to provide a method of evaluating each microstructured pattern of a semiconductor by calculating as a dislocation vector the relationship in position between the surface and bottom of the photoresist on the microstructured pattern. The present invention is also intended to provide a method of evaluating exposure accuracy quantitatively on a single-shot, single-chip, or wafer-by-wafer basis, or a method of evaluating each section of the pattern exposure system, detecting abnormality, and issuing a related warning. During microstructured pattern evaluation based on the present invention, the formation status of the patterns on the surface of the exposed layer (hereinafter, simply called the surface layer) and at the bottom of the exposed layer (hereinafter, simply called the bottom layer) and the relationship in position between the surface layer and the bottom. layer are analyzed, then the relative dislocation between both layers is calculated as a dislocation vector, and this vector is displayed on the screen of the corresponding apparatus. Also, a warning will be issued if the dislocation vector oversteps the dislocation tolerance that has been set beforehand. In addition, the exposure system, the wafer, and other targets can be evaluated by classifying calculated characteristic quantities according to the particular tendency and characterizing each single-shot, single-chip, or wafer area. That is to say, according to the present invention, the microstructured pattern inspection method for inspecting the microstructured patterns formed on the thin coating of a substrate through pattern optical exposure is characterized in that said inspection method comprises a process for acquiring images of the microstructured patterns formed on said thin coating, a process for identifying both the shape of the microstructured pattern on the surface of said thin coating and the shape of the microstructured pattern at the bottom of said thin coating, from said images, and a process for detecting the dislocation between the two microstructured patterns that have been identified in the third process mentioned above. The shapes of the microstructured patterns can be identified by detecting the profiles of the patterns. For circular microstructured patterns such as contact hole patterns, misalignment between the gravity center of the circular pattern on the surface of a thin coating and the gravity center of the circular pattern at the bottom of the thin coating is detected as a dislocation. For linear microstructured patterns, misalignment between the central axis of the linear pattern on the surface of said thin coating, and the central axis of the linear pattern at the bottom of said thin coating, is detected as said dislocation. The dislocation of microstructured patterns can be visually and easily recognized by displaying at the patterns an arrow indicating the size and direction of the dislocation. It is desirable that the profiles of the microstructured patterns be displayed as marks such as approximate curves or discontinuous dots. A microstructured pattern inspection method based on the present invention can further comprise a process in which said dislocation is detected at a plurality of positions within the required zone, and a process in which a dislocation that characterizes said zone is detected through statistical processing of the dislocation at said multiple positions. In this case, the dislocation of the entire microstructured patterns in the corresponding zone can be visually and easily recognized by displaying in that zone the appropriate arrow according to the particular size and direction of the dislocation characterizing the zone. This zone can be either a single-shot area or a single-chip area. Since a process for comparing the distribution tendency of the dislocation at said multiple positions, and the distribution tendency of the dislocation estimated to occur if trouble is detected in the corresponding microstructured pattern forming apparatus, is also included in the microstructured pattern inspection method described above, trouble with the microstructured pattern forming apparatus can be detected. In addition, according to the present invention, the microstructured pattern inspection method for inspecting the microstructured patterns formed on the thin coating of a substrate through pattern optical exposure is characterized in that said inspection method comprises a process for acquiring images of the microstructured patterns formed on said thin coating, a process for identifying the shapes of the microstructured patterns from said images, and a process for categorizing the corresponding microstructured patterns by the characteristic quantities of the respective shapes. This microstructured pattern inspection method can also include a process in which the corresponding microstructured patterns are categorized at a plurality of positions within a single-shot or single-chip area, and a process in which the categories of the microstructured patterns characterizing said single-shot or single-chip area are determined through statistical processing of the categorizing results obtained at said multiple positions. During statistical processing of the categorizing results, the quantity of inspection within, for example, each shot or each chip, and the number of microstructured patterns belonging to a specific category are compared and the highest pattern in terms of rate is characterized as a typical pattern at the particular position. Overall characteristics can be visually and easily identified by displaying a single-shot or single-chip zone in the appropriate color according to the particular category of the microstructured patterns characterizing the corresponding single-shot or single-chip area. Under the present invention, not only the edge positions corresponding to the surface and bottom of the exposed layers of the contact hole and/or linear patterns are displayed, but also the dislocation between the patterns on both layers is displayed as a dislocation vector at the same time. And a warning will be issued if the dislocation vector oversteps a predetermined tolerance. Thus, it becomes easy to automate the evaluation of microstructured pattern exposure accuracy and to confirm the exposure accuracy. In addition, not only the edge positions corresponding to the surface and bottom of the exposed layers of the contact hole and/or linear patterns are displayed, but also the characteristic quantities of exposed patterns in terms of shape are calculated at the same time. And a warning will be issued if these characteristic quantities overstep their tolerances. Thus, it becomes easy to automate the evaluation of microstructured pattern exposure accuracy and to confirm the exposure accuracy. In addition, it is valid to analyze the dislocation vector and characteristic quantities in combined form. Furthermore, useful data for trouble detection in the optics of the stepper, for statistical evaluation of thermal stresses due to thermal treatment over a wide range, and for statistical evaluation of lens aberration such as astigmatism or comatic aberration, can be collected by analyzing the distributions of the characteristic quantities of dislocation vectors and/or microstructured patterns over a broader area such as a single-chip or single-shot area or the entire wafer. And the inspection of said microstructured patterns to any multiple processes enables collected data to be fed back to subsequent processes. Embodiments of the present invention are described below with reference to the accompanying drawings. First, the methods of calculating and displaying the dislocation vectors with respect to the contact hole patterns and linear patterns formed on the exposed layer (photoresist coating) of the wafer are described. Next, the method of analyzing the causes of the dislocation by analyzing a multiplicity of dislocation vectors and deriving a general tendency is described. FIG. 1 is a schematic diagram showing an example of a microstructured pattern inspection apparatus designed to be used for an inspection method based on the present invention. In FIG. 1, a scanning-type electronic microscope is shown as a typical microstructured pattern inspection apparatus. Electron gun 1 provides heating filament 2 with electroheating to obtain electron beam 8. Electron beam 8, after being drawn from Wehnelt units 4, is accelerated by anodes 5, then condensed through condensing lenses 6, and scanned by deflecting coil unit 7 to which deflecting signals are applied from deflecting signal generator 15. After that, object lenses 9 focus the electron beam on sample 11 placed in samples compartment 10. Thus, electron beam 8 is scanned one-dimensionally or two-dimensionally across sample 11 on which microstructured patterns are inscribed. When electron beam 8 is radiated, secondary electrons will be generated in the vicinity of the surface of sample 11 according to the particular shape of the sample and these electrons will be detected by secondary electron detector 17. The secondary electrons that have thus been detected will then be amplified by amplifier 18 to become the luminance modulated signals of CRT 14 synchronized with deflecting signal generator 15. The luminance modulated signals will reproduce the secondary electron images generated on the surface of sample 11 by the electron beam 8 that was radiated in synchronization. Information on the microstructured patterns formed on the surface of the sample can be acquired using this procedure. The secondary electron images displayed on CRT 14 will be picked up by camera 13 as required. FIG. 3 is a flowchart showing the flow of microstructured pattern dislocation vector calculation based on the microstructured pattern image information that has thus been acquired. The methods of detecting and displaying dislocation vectors in the case that the microstructured patterns to undergo dislocation detection are contact hole patterns formed on the exposed layer (photoresist coating), are described below. In this case, although microstructured pattern images are acquired using a scanning-type electronic microscope, these pattern images can likewise be acquired using a means other than a scanning-type electronic microscope, such as an optical microscope. First, in step 11, the microstructured pattern images that have been acquired using a means such as a scanning-type electronic microscope, are displayed on an image display unit and then an image of any single contact hole pattern is specified using a mouse cursor or the like. In step 12, polar coordinate conversions are performed on the selected contact hole pattern image, then a plurality of cross-sectional waveform information is created as profiles on a fixed-angle basis in a radial direction from the center of the contact hole pattern, and these profiles are provided with various differentiation processes and threshold value processes to derive several target edges. Among all these target edges, only the edge corresponding to the exposed layer surface of the contact hole pattern (hereinafter, this edge is called the inner circle) and the edge corresponding to the exposed layer bottom (hereinafter, this edge is called the outer circle) are detected. The further structural complexity and finesse of the microstructured patterns themselves, improvements in the performance of the inspection apparatus to be used, and other factors are offering a more abundance in terms of the edge information obtained as profiles, thereby making it more difficult to detect the edge corresponding to the desired position. The sections corresponding to the above-mentioned outer and inner circles (edges), however, are abundant in edge information and exist at almost a fixed distance in all angle directions from the center of the contact hole (namely, those sections take a circular shape). Therefore, the edge corresponding to the desired position can be detected more accurately by deriving as more target edges as possible and then detecting the outer and inner circles from edge information. In step 13, the centers of gravity of the inner and outer circles that were detected in step 12 are derived as M1 and M2, respectively. In this step, although position information on the inner and outer circles is represented as the centers of gravity, the crossing point between the major and minor axes of a circle, for example, can also be taken as the position information relating to the circle. In this case, however, fixed criteria must always be used during a series of inspection processes for microstructured patterns. In step 14, the vector pointing from the gravity center M1 of the inner circle towards the gravity center M2 of the outer circle is calculated as the dislocation vector of the contact hole. Before this calculation is made, the tolerance for the dislocation of the microstructured patterns must be set through, for example, visually checking the image that was acquired by the inspection apparatus. The maximum and minimum allowable vectors should be established as the dislocation tolerance. Likewise, tolerances should also be set for the areas or major and minor diameters of the inner and outer circles, or for the area ratio between the circles. Thus, the calculated dislocation vector is judged whether it is out of the tolerance. As shown in FIG. 4, the inner and outer circles that have been measured at each angle with respect to the selected contact hole are displayed on the screen of the image display unit as the circles connecting the to-be-detected edges having the edge information corresponding to those measured circles, and as the arrow connecting the dislocation vector (calculated in step 14) from M1 towards M2. In FIG. 4, although the positive direction of the dislocation vector is shown as the direction from M1 to M2, the direction from M2 to M1 can also be set as the positive direction, only if fixed criteria is always used. During the judgment process of step 14, if the size and direction of the dislocation vector fall within the previously set tolerance, processing will advance from step 14 to step 15 and the inner and outer circles of the contact hole and the dislocation vector will be displayed in white on the screen to indicate that the circles and the dislocation vector stay within their tolerances. Conversely, if the size and direction of the dislocation vector overstep the previously set tolerance, processing will skip to step 16 and the inner and outer circles of the contact hole and the dislocation vector will be displayed in red to warn the user that the circles and the dislocation vector are outside their tolerances. In addition to or instead of the dislocation vector, the shapes of the inner and outer circles of the contact hole should be used as a criterion for judging whether the particular contact hole is an allowable hole. Typical categories relating to the shapes of the inner and outer circles include, as shown in FIG. 5, the degree of circularity (whether the circle is a true circle or an ellipsis), the ratio of the major and minor diameters, the absolute area value, or the area ratio of the inner and outer circles. These shapes of the circles should be categorized either as large, medium, or small shapes, or according to the particular ratio relative to a reference value. At the same time, tolerances on individual categories should also be established. The shapes of the inner and outer circles of the contact hole to be inspected are compared with the respective tolerances after being analyzed whether the shapes belong to which of the established categories. If the shape of the contact hole oversteps the tolerance, that contact hole will be displayed in color on the image display unit as a warning. FIG. 6 shows an example in which the shape of the contact hole will be displayed if the tolerance is overstepped. An example of the display made if the outer circle is greater than its maximum allowable major diameter is shown in FIG. 6(a), wherein the difference from the tolerance is displayed as an arrow and the outer circle itself is displayed in a color meaning a warning, such as red. An example of the display made if the outer circle is smaller than its minimum allowable major diameter is shown in FIG. 6 (b), wherein the difference from the tolerance is displayed as an arrow and the circle corresponding to the outer circle is displayed in a color meaning a warning, such as red. An example of the display made if the outer circle is smaller than its minimum allowable area is shown in FIG. 6(c), wherein the inside of the outer circle is displayed in a color meaning a warning, such as light red. Although the examples shown in FIG. 6 are for evaluating the shape of the outer circle of a contact hole, similar evaluations can also be performed on the inner circle of the contact hole. Next, the methods of detecting and displaying a dislocation vector in the case that the microstructured patterns to be inspected are linear patterns formed on exposed layers are described with reference being made to the flowcharts of FIGS. 3 and 7. First, in step 11 of FIG. 3, images of the linear patterns to be inspected using a microstructured pattern inspection apparatus such as a scanning-type electronic microscope or optical microscope. Next, in step 12, fixed detection range 21 is set, as shown in FIG. 7(a), for the acquired linear pattern images and then as shown in FIG. 7(b), edges are detected within detection range 21, wherein the linear edges on the surface and at the bottom of the exposed layer (photoresist coating). After this, processing proceeds to step 13, in which the central axes of the linear edges on the surface and at the bottom of the photoresist coating are obtained as L1 and L2, respectively, as shown in FIG. 7(b). FIG. 7(c) is a cross-sectional view of section A—A shown in FIG. 7(b). The perpendicular line from the center of axis L1 in detection range 21 to axis L2 is recognized as the dislocation vector (L1-L2) of the linear pattern as shown in FIG. 7(d). In this case as well, the tolerance for the dislocation is set through, for example, visual image checks using the inspection apparatus. In step 14, comparison is made between the dislocation vector that was calculated in step 13, and the dislocation tolerance that has been established beforehand. During the judgment process of step 14, if the size of the calculated dislocation vector falls within the previously set tolerance, processing will skip to step 16 and the edge and dislocation vector of the linear pattern will be displayed in red as a warning. Conversely, if the size of the dislocation vector oversteps the previously set tolerance, processing will advance to step 15 and the edge and dislocation vector of the linear pattern will be displayed in white on the screen. As with those of contact hole patterns, the shapes of linear patterns can be categorized separately for the surface and bottom each of the exposed layer (photoresist coating), and whether the particular linear pattern is an allowable pattern can be judged. Typical categories relating to the shapes of linear patterns include, as shown in FIG. 8, the shape, line width, etc. of the pattern. Tolerances should also be established for the shapes and widths of the linear patterns so that if a linear pattern oversteps the tolerances, that linear pattern will be displayed in a color, such as red, to warn the operator. Next, the evaluation of a plurality of stepper-exposed contact hole and linear patterns or other microstructured patterns, especially, the method of evaluating an area equivalent to a single reticle shot or chip is described. An example of evaluating microstructured patterns using two indexes . . . dislocation vector and shape . . . is shown in this description. As shown in FIG. 9, multiple chips (31a, 31b, 31c, and so on) usually exist in single-shot area 30. First, a single shot of image information on exposed patterns is acquired by the scanning-type electronic microscope or other inspection apparatus. Contact hole patterns or linear patterns are selected at multiple positions within a single-shot area, then shape information is acquired for each pattern, and the dislocation vectors of each contact hole or linear pattern are calculated using the method described in the flowchart of FIG. 3. At this time, in chips 31a, 31b, 31c, and so on, of a single-shot area, sample patterns for calculating dislocation vectors at typical positions such as the corners (32a to 32d) and center (32e) of each chip, should be selected in order to implement chip comparison as well as shot comparison. Also, it is desirable that unless inspection throughput does not decrease significantly, more such sample patterns as possible should be selected at equal intervals within the chip area. In addition, these sample patterns should be acquired at the same position of each chip. The dislocation vectors that have been calculated for each contact hole pattern or linear pattern are displayed as arrows each originating from, for example, the gravity center position of the particular contact hole pattern or linear pattern. If the calculated dislocation vectors overstep the respective tolerances, a warning will be displayed in red. With respect to these calculated dislocation vectors at each sample within the single-shot or single-chip area, the corresponding patterns will then be categorized as shown in FIG. 10. For the entire single-shot area, the patterns will be categorized according to the size (large, medium, or small) of the entire dislocation vector shown in FIG. 10(a), and according to the direction (either of about eight directions such as top, upper right, right, lower right, bottom, lower left, left, and upper left) of the entire dislocation vector shown in FIG. 10(b). The contact hole patterns or linear patterns are also categorized according to the particular direction and dimensional deviation of each dislocation vector that was acquired at a typical position within the single-shot or single-chip area. For direction, the dislocation vector at each sample is characterized, depending on, for example, as shown in FIG. 10(c), whether the vector points in the same direction, outward, inward, or in an irregular direction. For dimensional deviations, individual dislocation vectors are characterized, depending on, for example, as shown in FIG. 10(d), whether the patterns are equal, large only at edges, large only in the center of the reticle, or large in a specific position only. Each characteristic quantity is linked to the area from which the particular characteristics have been extracted. The methods of categorizing patterns are not limited to the four types shown in FIG. 10; other characteristic quantities can be used instead, provided that they represent the tendencies of the dislocation vectors within the single-shot area. The dislocation vectors representing the entire single-shot or single-chip area are calculated as follows: In the “k”th area of chips, for example, a contact hole pattern of one “k” chip and a linear pattern of two “k” chips are set as sample patterns for the calculation of the corresponding dislocation vectors, and each chip is provided with such processing as described in the flowchart of FIG. 3. When the dislocation vectors that have thus been calculated for the contact hole pattern are taken as SH1, SH2, and so on up to SHk1, and the calculated dislocation vectors of the linear pattern are taken as SL1, SL2, and so on up to SLk2, dislocation vector VCk representing the chip can be calculated using expression 1 below. If each pattern differs in design specifications, since the sizes of the dislocation vectors calculated will also differ, adjustments will be performed using coefficients α and β. The dislocation vectors representing each shot area can also be calculated similarly. VC k _ = ∑ i = 1 k ⁢ ⁢ 1 ⁢ α i ⁢ SH i _ + ∑ j = 1 k ⁢ ⁢ 2 ⁢ β j ⁢ SL i _ [ Expression ] After the contact hole and linear patterns have been categorized by their shapes as shown in FIG. 5 or 6, the results are statistically processed in the single-shot or single-chip range, and for example, the largest value in terms of the number of categories is taken as a typical value of the shape relating to the corresponding area. The occurrence of some abnormality caused by the four factors described earlier in this SPECIFICATION can be estimated by characterization relating to the thus-calculated sizes and distributions of the dislocation vectors within a single-shot area, and from categorizing results on the shapes of the contact hole or linear patterns. FIG. 11 shows the tendency of dislocation vectors occurring in a single-shot area when lens aberration is detected in the pattern projection optics. For example, if, as shown in FIG. 11(a), the dislocation vector points in a radially inward direction from the center of the reticle within a single-shot area, or if the contact hole is deformed into either a vertically long shape towards the center of the reticle as shown in FIG. 11(b), or a horizontally long shape towards the center of the reticle as shown in FIG. 11(c), such abnormality is likely to be due to lens aberration in the stepper. If these characteristics are detected, therefore, a warning implying the occurrence of lens aberration in the projection optics of the stepper will be displayed along with images of the corresponding pattern. FIG. 12 shows the tendency of dislocation vectors occurring when the projection optics is axially misaligned or has any inclined lenses. If, as shown in FIG. 12, multiple dislocation vectors within a single-shot area point in the same direction, this implies abnormality due to axial misalignment of the projection optics. If these characteristics are detected, therefore, a warning will be issued by, for example, displaying a message indicating the abnormality. FIG. 13 is an explanatory diagram of the linear patterns formed when defocusing due to lens heating is occurring. The linear pattern formed when the best focus is obtained, is shown in FIG. 13(a), and the linear patterns formed during defocusing are shown in FIGS. 13(b) and (c). Shown at the left of FIGS. 13(a), (b), (c) each are top views of the linear pattern, and shown at right are cross-sectional epitomic views of the linear pattern. FIG. 13(b) shows a linear pattern whose defocusing direction is plus (this indicates that the focal position is above the exposed surface), and this linear pattern has a thin top and is thicker as it goes downward. FIG. 13(c) shows a linear pattern whose defocusing direction is minus (this indicates that the focal position is below the exposed surface), and this linear pattern has a thin top and a flared, indistinct bottom. Since these patterns having a thin top and/or a thick/indistinct bottom are likely to be due to defocusing, a warning is displayed to imply the occurrence of the abnormality. Lens heating is caused by the accumulation of heat inside, and on the surfaces of the, lenses due to continued exposure for a long time. Characteristics on the “lens heating” event of the lenses to be used can be understood by examining chronological changes in the shape of the pattern. FIG. 14 shows an example of a tendency occurring with the dislocation vectors if the wafer itself is deformed or if the photoresist coating is not uniform. Warped or deflected wafer or nonuniform photoresist coating affects the axial misalignment of the entire wafer significantly. Factors due to defects in wafer status, however, can be evaluated by calculating dislocation vectors with respect to each chip within each wafer and examining their tendencies. As briefly shown in FIG. 14, abnormality due to either defects in the status of the wafer itself or nonuniform photoresist coating, is usually distributed in one specific area of wafer 30. Therefore, the occurrence of abnormality due to either defects in the status of the wafer itself or nonuniform photoresist coating, can be estimated by concentrating attention on such specific characteristics and analyzing their distributions within the wafer area. The method of displaying information on the dislocation vectors and shapes of microstructured patterns such as contact hole and linear patterns, is described next. One or more areas are specified for each chip in each wafer area, and any dislocation vectors in the specified area(s) are calculated. Also, dislocation vectors for each chip or each shot are characterized using a similar method to [Expression 1] shown above. When information on the dislocations of microstructured patterns is displayed, either a view showing the wafer when it is partitioned into shot areas, or a view showing a specific shot area when it is partitioned into chip areas is displayed on the screen of the display unit first and then the dislocation vectors that were calculated for each shot area of the wafer or for each chip area in a specific shot are displayed in color. As with the processing sequence shown in the flowchart of FIG. 3, if the dislocation vectors overstep the respective tolerances for each shot or each chip, a warning will be issued by displaying the vectors in a conspicuous color such as red. FIG. 15 is an explanatory diagram of the saving format of the dislocation vector and characteristic quantity data calculations obtained from each pattern of a wafer. The data is of the tree structure having a hierarchy covering the wafer, shots, chips, and in-chip patterns. Each in-chip pattern record has pattern's x- and y-coordinates, pattern information (whether the pattern has a linear shape or a contact hole shape), the size and direction of the dislocation vector of the corresponding pattern, shape information, and other characteristic quantities. On a chip-by-chip basis, the average of various information on the pattern belonging to the chip is retained as a record of that chip. Likewise, on a shot-by-shot basis, the average of various information on the chip corresponding to the shot is retained as a record. Also, each value retains as its “parent” the ID of the area of the immediately upper hierarchical level, as its “brother” the ID of an area derived from that parent, and as its “child” the ID of the immediately lower hierarchical level of direct lineage. Chip “3”, for example, retains “1” as its parent, “4” as its brother, and “7” and “8” as its children. Examples in which the dislocation vector characteristic quantities that have been acquired using the method described above are statistically processed and displayed on the screen, are shown in FIGS. 16 and 17. The display shown in FIG. 16 relates to the corresponding wafer, and the display in FIG. 17 is for the corresponding shot range. As shown in FIG. 16, wafer display mode displays information on a shot-by-shot basis. On the wafer map, each shot area is partitioned by a shape such as a square, and the characteristic quantity and dislocation vector of each entire shot area are displayed. A specific number from 1 to 16 is assigned to each shot area, with the number corresponding to the coordinates within the wafer. Each shot area from 1 to 16 on the wafer map is displayed properly in color coded form according to the characteristic quantity representing the shot (the greatest characteristic quantity in the shot: A, B, C, or, D). Also, the dislocation vector representing the shot area is displayed in overlapped form on that shot area. The distribution of characteristic quantities on the shape of the microstructured pattern is digitally displayed in the table at the bottom of the display. Numerals in this table denote the number of times each characteristic quantity appeared in each shot area. At the right end of the table is displayed the total number of times each characteristic quantity appeared in the entire shot range, and if this appearance tendency shows any characteristics, these characteristics will be displayed under “Evaluation”. When a typical tendency is analyzed beforehand and actual evaluations apply to that tendency, explanatory statements on further detailed analyses on the tendency will be displayed with “(1)” or “(2)” at the bottom of the screen display. As shown in FIG. 17, chip display mode displays information on a chip-by-chip basis. In shot display mode, a map of the wafer is also displayed at the same time to indicate to what position on the wafer map the current shot corresponds. Each chip from 1 to 8 within the shot is displayed properly in color coded form according to the characteristic quantity representing the chip (the greatest characteristic quantity in the chip: A, B, C, or, D). Also, the dislocation vector representing the chip is displayed in overlapped form on that chip. The distribution of characteristic quantities on the shape of the microstructured pattern is digitally displayed in the table at the bottom of the display. At the right end of the table is displayed the total number of times each characteristic quantity appeared, and if this appearance tendency shows any characteristics, these characteristics will be displayed under “Evaluation”. When a typical tendency is analyzed beforehand and actual evaluations apply to that tendency, explanatory statements on further detailed analyses on the tendency will be displayed with “(1)” or “(2)” at the bottom of the screen display. In the example of FIG. 17, “Abnormal” is shown as the evaluation of characteristic quantity B, and the column of chip 1 is displayed in light red. The display shown in FIG. 16 or 17 changes according to the characteristic quantity to which attention is to be given (the layout of the display remains the same). For example, if this characteristic quantity is “A: Characteristics of the circle” as shown at the top of FIG. 5, the characters “True circle”, “vertically long”, “Horizontally long”, “Oblique (1)”, and “Oblique (2)”, are assigned to the items of characteristic quantities A, B, C, D, and E, respectively, in FIG. 16 or 17. When five categories are present, the number of items is also five (from A to E) and five different colors are assigned as display colors. The display of each shot or chip area is coded in the color corresponding to the characteristic quantity representing the area. Also, “Characteristic quantity” in the table functions as a button, and with each press of this button, the categorizing basis in FIG. 5 changes to “Characteristics of the circle” first and then “Ellipticity”, “Area”, and so on, in that order. As “Characteristic quantity” changes in this way, the numeric data in the table and the display color of the shot area within the wafer map or of the chip area within the shot will also correspondingly change. Although it is not shown in the corresponding FIG., display mode for a single-chip range is also provided. This display mode for a single-chip range is very similar to the display mode for a single-shot range, and in the single-chip display mode, any dislocation vectors of the sample patterns within one chip are displayed at the patterns. The shot display also appears at the same time so that the position of the current chip in the shot can be readily identified. FIG. 18 shows the relationship between wafer display, shot display, and chip display. In the wafer display mode shown in FIG. 18(a), for example, if the operator clicks in shot area 2 on the display with a large dislocation vector, the current display will change to the shot display mode to display that shot in enlarged form as shown in FIG. 18(b). Average dislocation vectors on each chip of the shot are displayed in the shot display mode, and in this mode, if the operator clicks at chip 7 on the display with a large dislocation vector, that chip will be displayed in enlarged form and the distribution of dislocation vectors in the chip will also be displayed, as shown in FIG. 18(c). Thus, the position with a significant dislocation vector can be detected. It is also possible to move control to the shot display mode by double-clicking on the shot display, and to return control to the original shot display mode by double-clicking on the chip display. The database structure shown in FIG. 15 is used during movement from the wafer display mode to the shot display mode, or vice versa. For example, when control is moved from the display of shot 1 to that of a chip, the corresponding chip display is created using the information of chips 3 and 4. FIG. 19 is a flowchart explaining the entire procedure relating to microstructured pattern inspection based on the present invention. First, in step 21, the wafer to be inspected is loaded into an inspection apparatus such as a scanning-type electronic microscope or optical microscope. Next, in step 22, the shot (or chip) to be inspected for dislocation vector or geometrical characteristics of the microstructured pattern is specified, and processing further advances to step 23, wherein the dislocation vector calculating position in the shot (or chip) is then specified. Next, in steps 24 to 28, dislocation vector calculation and characterization are executed for the specified microstructured pattern. In step 29, the calculated dislocation vector or the characteristic quantity of shape is judged whether the corresponding tolerance is overstepped, and if the tolerance is not overstepped, processing will proceed to step 30, wherein the dislocation vector or the microstructured pattern will then be displayed in normal color. Conversely, if the tolerance is overstepped, processing will skip to step 31, wherein the dislocation vector or the microstructured pattern will then be displayed in red as a warning. Processing will proceed to step 32, wherein characteristic tendencies on either the distribution of the dislocation vectors that were calculated in steps 24 to 28, or the shape of the specified microstructured pattern will then be statistically analyzed. Processing will further proceed to step 33, wherein judgment will be made whether the tendency of characteristic quantities that was analyzed in step 32 will imply abnormality about the stepper or wafer. In the judgment process of step 33, a combination of, for example, such dislocation vector distribution patterns as shown in FIGS. 11(a), 12, and 14, and the known causes of the abnormality, or a combination of such pattern shape-related characteristic quantity distribution patterns as shown in FIGS. 11(b), 11 (c), and 13, and the known causes of the abnormality, is retained as a table, and the tendency of the characteristic quantities that were calculated in step 32 is checked against the table to search for the actual cause of the abnormality. If the distribution pattern of the dislocation vectors or the distribution of the shape-related characteristic quantities of the microstructured pattern exists in the table and implies abnormality about the stepper or wafer, processing will advance to step 34 and a warning message on the cause of the abnormality will be displayed. According to the present invention, microstructured pattern exposure accuracy can be automatically evaluated and easily confirmed. Also, trouble in the optics of the stepper or in the wafer can be detected by evaluating the distributions of the characteristics of microstructured patterns over a broader area such as a single-chip or single-shot area or the entire wafer.
054901871	description	DETAILED DESCRIPTION OF THE INVENTION Experimental studies by Applicants have led to in situ observations by hot-stage transmission electron microscopy (TEM) of anomalously rapid helium bubble diffusion in aluminum with a low concentration of lead, and in aluminum with a low concentration of indium, at annealing temperatures above the melting point of the impurity species. In these experimental studies, samples of 99.999% pure aluminum alloyed with 200 ppm by weight of lead, and separately, with 1000 ppm by weight of indium, were thinned to electron transparency and subsequently irradiated with 50-keV helium ions to produce a helium concentration of approximately 20 atomic ppm. The implanted samples were then annealed at 723-743 K for several minutes, during which time video recordings were made of spherical helium bubbles undergoing Brownian motion and eventually coalescing or disappearing at a foil surface. The participation of the impurity, which is not visibly apparent at the annealing temperature, was verified in each case by cycling the sample temperature between room temperature and the annealing temperature. It was observed that solid precipitates attached to helium bubble facets appeared during slow cooling to room temperature but did not appear during a rapid quench. In the latter case, the precipitate subsequently formed at approximately 520 K, and disappeared again above the melting temperature of the impurity, as the sample temperature was increased. This is shown in FIG. 1 which is a bright-field electron micrograph, taken after slow cooling the aluminum matrix to room temperature. FIG. 1 shows solid indium precipitates (dark spots) attached to preferred helium bubbles (white spheres) in the aluminum matrix. Also apparent in FIG. 1 as collections of dark spots (indium) superimposed on the light spherical region are remnants of helium bubbles that have reached a foil surface. FIG. 1 also illustrates the insolubility of the indium with the host aluminum metal. Video images were used to obtain bubble diffusion coefficients D.sub.b at the annealing temperatures in the following manner. Spatial displacements transverse to the electron beam were measured for each of several lead- and indium-coated bubbles during successive 1 second time intervals. The collection of N measurements for each bubble must possess (in the limit of an infinite number of measurements) a Gaussian probability distribution, since the N measurements can be regarded as single measurements for N noninteracting, identical bubbles, all initially located together on a two-dimensional plane at r=0 and at time t=0. Thus the radial distribution of measurements r at time t can be expressed by the following equation: ##EQU1## so that integrating p over the entire plane produces the total N measurements. The number of displacements r between r.sub.i and r.sub.j (with r.sub.i <r.sub.j) is then approximately EQU n.sub.ij =N exp [-r.sub.i.sup.2 /4D.sub.b t]-N exp [-r.sub.j.sup.2 /4D.sub.b t] This expression provides the areas N.sub.i,i+1 for Gaussian histograms that are compared to the histograms of measured bubble displacements. The bubble diffusion coefficient D.sub.b that provides the best match, for each of the monitored helium bubbles, is presented in the following Table 1. TABLE 1 ______________________________________ R (nm) D.sub.b (nm.sup.2 /s) D.sub.s (.mu.m.sup.2 /s) ______________________________________ Pb/He 5.15 2.0 0.70 6.0 1.2 0.77 In/He 7.9 2.0 3.85 16.0 7.0 227.0 26.5 0.8 195.0 ______________________________________ The rapid bubble diffusion shown in Table 1 results from enhanced diffusion of aluminum atoms at the bubble/matrix interface. If the latter is assumed independent of bubble size, the corresponding surface diffusion coefficients D.sub.s may be calculated from the following standard relationship: EQU D.sub.b =(3.OMEGA..sup.4/3 /2.pi.R.sup.4)D.sub.s where R is the gas bubble radius and .OMEGA. is the volume of a matrix atom. These values are given in Table 1 and are also presented in FIG. 2 together with D.sub.s taken from other experiments showing helium bubble growth in pure aluminum at various annealing temperatures. FIG. 2 shows the calculated surface diffusion coefficients D.sub.s plotted against the scaled annealing temperature T/T.sub.m for helium bubble diffusion in aluminum. In FIG. 2, T.sub.m is the melting temperature (933 K) of the aluminum matrix. The open circles and the crosses shown in FIG. 2 indicate values of D.sub.s for bubbles with attached liquid lead and indium precipitates, respectively, determined from direct observation of their Brownian motion at 723-743 K. (The numerical values are shown in Table 1). The open and solid diamonds in FIG. 2 indicate the D.sub.s (m.sup.2 s.sup.-1) values for helium bubbles with and without attached lead precipitates, respectively, at 823 K, derived from experimental studies by Applicants. The solid circle shows the average value of D.sub.s determined from measurements of coarsening of helium bubbles in neutron-irradiated, helium-implanted pure aluminum, during annealing at 0.96 T.sub.m. The bars associated with that point indicate the range of five values. The solid curve shown in FIG. 2 is obtained from the expression EQU D.sub.s =0.086 exp [-(2.1 eV)/kT]m.sup.2 s.sup.-1 which is a fit to the data point with a 2.1 eV activation energy for surface diffusion. The bars at 0.83T.sub.m (823 K) indicate the estimate of D.sub.s derived from similar measurements of bubble growth in helium-implanted pure aluminum. The mechanism by which atomic diffusion at the bubble surface is increased is unclear. However, it is important to note that the binary phase diagrams for these aluminum alloys show negligible solubility of the impurity in the matrix material so that the impurity will segregate to the free surfaces provided by the gas bubbles; an impurity melting temperature lower than that of the matrix and of the annealing temperature; and some solubility of the matrix atoms in the liquid impurity. These characteristics suggest a liquid dissolution process, whereby a liquid layer of impurity atoms at the bubble surface acts as a conduit for rapid transport of dissolved aluminum atoms. Two liquid dissolution mechanisms for bubble diffusion, that rely on the properties of the attached liquid precipitates have been considered by Applicants. Volume diffusion of an equilibrium concentration of aluminum atoms through a thin layer of liquid impurity at the bubble surface produces bubble diffusion coefficients in good agreement with those derived from observations. Alternatively, the liquid coating may instead simply remove the bubble facets. In a preferred embodiment of the present invention, the direction of bubble or void migration is biased by the application of a temperature gradient across the host metal or alloy which contains small amounts of impurities, such as lead or indium. For example, those skilled in the art of nuclear reactor technology know that during the fission process the internal temperature of a fuel rod will be greater than the external or cladding temperature, thereby constituting a temperature gradient across the fuel rod cladding. The same is true for nuclear reactor containment structural materials, wherein the internal surface temperature of a containment vessel will be greater than the external surface temperature, thereby creating a temperature gradient across the containment structural material. The temperature gradient to be applied should be such that the higher temperature is greater that the melting point of the impurity metal particles, but lower than the melting point of the host metal or metal alloy. The diffusing surface atoms will tend to move from the hotter side of the bubble or void toward the colder side, thus producing a net movement of the bubble or void up the temperature gradient and out of the metal/alloy material. Controlling the migration of the bubbles and voids is particularly advantageous in fusion and fission reactors and results in preventing the known long-term deleterious effects of inert gases in the reactor cladding or containment structural materials. The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments described explain the principles of the invention and practical application and enable others skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.
051397340	abstract	A unique resin processing system for providing and removing resin to large demineralizer vessels during chemical decontamination of nuclear reactor primary systems is disclosed. Resin is premeasured in a batching tank for accurate filling of demineralilzer resin bed while minimizing personnel radioactivity exposure. Sluice water transfers spent resin to a storage tank and, thereafter, is recycled for subsequent sluicing operations. Spent resin from the storage tank is periodically delivered to high integrity containers for ultimate disposal.
	claims	1. A nuclear medical diagnostic device, comprising:a plurality of γ-ray detectors, circularly disposed, and converting incident γ-rays to electric signals;a collimator unit comprising a one dimensional collimator arranged along a front of the plurality of the γ-ray detectors in a rotatable manner and one dimensional collimator having a shielding material arranged in a direction and residing on a part of a peripheral of the plurality of the γ-ray detectors and shielding a part of single photons, and a plurality of ceptors fixed on a whole periphery in the front of the plurality of γ-ray detectors, wherein the ceptors and the shielding material of the one dimensional collimator are combined to form a two dimensional collimator, wherein the two dimension collimator has a shielding material formed into a lattice shape;a collimator position detecting mechanism, detecting a position of the collimator;a simultaneous measuring mechanism, outputting the electric signals about simultaneously output from the plurality of γ-ray detectors as simultaneous measuring signals;an energy discriminating mechanism, discriminating first signals and second signals among the electric signals output from the plurality of γ-ray detectors, wherein the first signals are generated by the single photons emitted from a first agent accumulated in a test subject, and the second signals are generated by positrons emitted from a second agent accumulated in the test subject;a first position specifying mechanism, specifying a position of the first agent accumulated in the test subject according to the first signals and the position of the collimator; anda second position specifying mechanism, specifying a position of the second agent accumulated in the test subject according to the simultaneous measuring signals and the second signals,wherein the positions of the first agent and the second agent are simultaneously specified. 2. The nuclear medical diagnostic device according to claim 1, whereinthe energy discriminating mechanism further comprises a scattered ray removing mechanism, and the scattered ray removing mechanism removes the signals that are about simultaneously measured by two γ-ray detectors among the plurality of γ-ray detectors from the first signals, so as to reduce an influence due to a scattered ray of an annihilation γ-ray generated by the positrons emitted from the second agent accumulated in the test subject.
	claims	1. A scintillator array comprising:a first scintillator element;a second scintillator element; anda reflector provided between the first and second scintillator elements and having a width of 80 μm or less therebetween,wherein each scintillator element includes a polycrystal containing a rare earth oxysulfide phosphor, the polycrystal having a radiation incident surface of 1 mm or less×1 mm or less in area,wherein an average crystal grain diameter of the polycrystal is not less than 5 μm nor more than 30 μm, the average crystal grain diameter being defined by an average intercept length of crystal grains in an observation image of the polycrystal with a scanning electron microscope,wherein a maximum length or a maximum diameter of defects on the polycrystal is 40 μm or less, andwherein a ratio of a total area of defects on a scanning surface to an area thereof is 10% or less, the ratio being, defined by inspecting an inside of the polycrystal under a measurement condition including a frequency of 200 MHz, a focal length of 2.9 mm, a scanning pitch of 2.5 μm, a scanning surface size of 1 mm×1 mm, a sample thickness of 1 mm, and a detection limit defect length of 3 μm using ultrasonic flaw detection. 2. The scintillator array according to claim 1, wherein the defect includes at least one selected from the group consisting of a hole, a flaw, a foreign material including a component different from a component of the rare earth oxysulfide phosphor, a hetero-phase having the same components as components of, and a crystal structure different from a crystal structure of, the rare earth oxysulfide phosphor, and a hetero-phase including a component different from a component of the rare earth oxysulfide phosphor. 3. The scintillator array according to claim 1, wherein the rare earth oxysulfide phosphor is expressed by a formula of A2O2S:Pr, wherein A is at least one element selected from the group consisting of Y, Gd, La and Lu,or wherein the rare earth oxysulfide phosphor is expressed by a formula of (Gd1-xA′x)2O2S:Pr, wherein A′ is at least one element selected from the group consisting of Y, La and Lu, and x is a number satisfying 0≤x≤0.1. 4. The scintillator array according to claim 3, wherein the rare earth oxysulfide phosphor contains at least one element selected from the group consisting of cerium, zirconium, and phosphorus. 5. A radiation detector comprising:the scintillator array according to claim 1; anda photoelectric converter to convert light from the scintillator array into electricity. 6. A radiation inspection device comprising:a radiation source to irradiate an inspection object with radiation rays; andthe radiation detector according to claim 5, the radiation detector being configured to detect radiation rays through the inspection object.
	summary
	summary
	claims	1. A nuclear power system, comprising:a reactor vessel that comprises a reactor core mounted within a volume of the reactor vessel, the reactor core comprising one or more nuclear fuel assemblies configured to generate a nuclear fission reaction;a riser positioned above the reactor core;a primary coolant flow path that extends from a bottom portion of the volume below the reactor core, through the reactor core, within the riser, and through an annulus between the riser and the reactor vessel back to the bottom portion of the volume;a primary coolant that circulates through the primary coolant flow path to receive heat from the nuclear fission reaction and release the received heat to generate electric power in a power generation system fluidly or thermally coupled to the primary coolant flow path; anda control rod assembly system positioned in the reactor vessel and configured to position a plurality of control rods in only two discrete stationary positions, such that the plurality of control rods are fully withdrawn from the reactor core in a first discrete position of the only two discrete stationary positions and the plurality of control rods are fully inserted into the reactor core in a second discrete position of the only two discrete stationary positions, and wherein the nuclear power system does not include any other control rods positioned within the reactor vessel and configured to control a power output of the nuclear fission reaction. 2. The nuclear power system of claim 1, wherein the control rod assembly is configured to adjust the plurality of control rods from the first discrete position to the second discrete position by at least one of:releasing the plurality of control rods to fall to the second discrete position from the first discrete position; orforcibly urging the plurality of control rods from the first discrete position to the second discrete position. 3. The nuclear power system of claim 1, wherein the plurality of control rods are sufficient to shut down the nuclear fission reaction or maintain the nuclear fission reaction at a sub-critical state in the second discrete position. 4. The nuclear power system of claim 1, further comprising a control system communicably coupled to the power generation system and configured to control a power output of the nuclear fission reaction independent of the control rod assembly system during a normal operation of the nuclear power system. 5. The nuclear power system of claim 4, wherein the control system is configured to perform operations to control one or more parameters of the power generation system comprising:determining that the power output of the nuclear fission reaction is greater than an upper value or less than a lower value;based on the determination, controlling the power generation system to adjust at least one of a turbine inlet steam valve or a feed water pump to adjust the power output of the nuclear fission reaction; andsubsequent to the adjustment, determining that the power output is within a range between the upper and lower values. 6. The nuclear power system of claim 5, wherein the operation of controlling the power generation system to adjust at least one of the turbine inlet steam valve or the feed water pump to adjust the power output of the nuclear fission reaction comprises at least one of:adjusting the turbine inlet steam valve toward a fully closed position to decrease the power output of the nuclear fission reaction, or adjusting the turbine inlet steam valve toward a fully open position to increase the power output of the nuclear fission reaction; ordecreasing an output flowrate of the feed water pump to decrease the power output of the nuclear fission reaction, or increasing the output flowrate of the feed water pump to increase the power output of the nuclear fission reaction. 7. The nuclear power system of claim 4, wherein the control system is configured to perform operations to control one or more parameters of a chemical injection system comprising:determining that the power output of the nuclear fission reaction is greater than an upper value or less than a lower value;based on the determination, adjusting an amount of a chemical injected into the reactor core from the chemical injection system to adjust the power output of the nuclear fission reaction; andsubsequent to the adjustment, determining that the power output is within a range between the upper and lower values. 8. The nuclear power system of claim 7, wherein the operation of adjusting the amount of the chemical injected into the reactor core from the chemical injection system comprises at least one of:increasing the amount of the chemical injected into the reactor core from the chemical injection system to decrease the power output of the nuclear fission reaction; ordecreasing the amount of the chemical injected into the reactor core from the chemical injection system to increase the power output of the nuclear fission reaction.
	claims	1. A method of manufacturing a top nozzle for a nuclear fuel assembly, the method comprising steps of:(a) casting a main body of the top nozzle, the main body being integrated into a single body with a coupling plate coupled to a guide thimble and a perimeter wall protruding upwards from a perimeter of the coupling plate;(b) forming a fastening pin hole in a vertical direction extending through an upper surface of a spring clamp provided on the top nozzle;(c) forming an elliptical pin head seat having a closed elliptical shape inside the upper surface of the spring clamp such that the elliptical pin head seat encloses an upper end portion of the fastening pin hole and, when taken from a plan view, the elliptical pin head seat is entirely enclosed by solid portions of the spring clamp without being open to or exposed to an exterior;(d) inserting a drill tip or a milling tip into the elliptical pin head seat and additionally removing an interior portion of the body of the spring clamp by the tip, after the elliptical pin head seat is completed and before forming a spring insert hole, thereby reducing time taken to conduct an electro-discharge machining process;(e) forming the spring insert hole by performing the electro-discharge machining process upon the spring clamp in an insert direction of a hold-down spring unit so that the spring insert hole has an upper surface, a lower surface, an outer side surface, an inner side surface and a back surface, with at least the outer side surface and the inner side surface completely closing an outer side and an inner side, respectively, of the spring insert hole;(f) coupling an end of the hold-down spring unit into the spring insert hole via a front side thereof;(g) providing a fastening pin having an elliptical shaped head, the elliptical shaped head being fitted into the elliptical pin head seat; and(h) inserting the fastening pin into the fastening pin hole, wherein the steps (a), (b), (c), (d), (e), (f), (g) and (h) are performed in this order. 2. A method of manufacturing a top nozzle for a nuclear fuel assembly, the method comprising steps of:(a) casting a main body of the top nozzle, the main body being integrated into a single body with a coupling plate coupled to a guide thimble and a perimeter wall protruding upwards from a perimeter of the coupling plate;(b) forming a fastening pin hole in a vertical direction extending through an upper surface of a spring clamp provided on the top nozzle;(c) forming an elliptical pin head seat having a closed elliptical shape in an upper end of the fastening pin hole and inside the upper surface of the spring clamp such that the elliptical pin head seat encloses an upper end portion of the fastening pin hole and, when taken from a plan view, the elliptical pin head seat is entirely enclosed by solid portions of the spring clamp, without being open to or exposed to an exterior;(d) inserting a drill tip or a milling tip into the elliptical pin head seat and additionally removing an interior portion of the body of the spring clamp by the tip, after the elliptical pin head seat is completed and before forming a spring insert hole, thereby reducing time taken to conduct an electro-discharge machining process;(e) forming the spring insert hole by performing the electro-discharge machining process upon the spring clamp in an insert direction of a hold-down spring unit so that the spring insert hole has an upper surface, a lower surface, an outer side surface, an inner side surface and a back surface, with at least the outer side surface and the inner side surface completely closing an outer side and an inner side, respectively, of the spring insert hole;(f) coupling an end of the hold-down spring unit into the spring insert hole via a front side thereof;(g) providing a fastening pin having an elliptical shaped head, the elliptical shaped head being fitted into the elliptical pin head seat; and(h) inserting the fastening pin into the fastening pin hole,wherein the steps (a), (b), (c), (d), (e), (f) and (g) are performed in this order.
	description	This application claims priority to U.S. Provisional Patent Application No. 62/774,303, filed Dec. 2, 2018, titled PROCESSING ULTRA HIGH TEMPERATURE ZIRCONIUM CARBIDE MICROENCAPSULATED NUCLEAR FUEL, the entire disclosure of which is incorporated by reference herein. The entire disclosures of U.S. Pat. No. 9,299,464 B2 “Fully Ceramic Nuclear Fuel and Related Methods” and U. S. Patent 2017/0025192 A1 “Method for Fabrication of Fully Ceramic Microencapsulated Nuclear Fuel” are incorporated by reference herein. This invention relates to a nuclear fuel. More specifically this invention describes a new fuel form and the method for fabrication of this inert matrix fuel whereby a fragile fuel microencapsulation is consolidated within an ultra-high-temperature-ceramic (UHTC) (zirconium carbide) that serves as a secondary and very high-temperature barrier to fission product release. There are many known types of nuclear fuel for both research, power producing nuclear reactors, and reactor for space exploration. The most common example of nuclear fuel is the ceramic uranium oxide pellet that is contained within a thin metallic cladding. That cladding both provides a rigid structure to hold the fuel and serves as the barrier to fission product release to the coolant stream. A second example of nuclear fuel is an inert matrix fuel (IMF) in which a fissile material such as (or containing) U-235 is dispersed in an inert host matrix. That inert matrix may be a refractory ceramic and is intended to provide a rigid host for the fuel as well as provide a measure of fission product retention. Yet a third example is a microencapsulated fuel, in one example known as the fully ceramic microencapsulated FCM™ fuel. This fuel type, similar to that of the IMF, has a distinct non-fuel matrix surrounding a plurality of fueled particles otherwise known as microencapsulations. In contrast with the IMF the microencapsulated fuels utilize an engineered fuel microencapsulation, such as the tri-isotropic (TRISO) or bi-isotropic (BISO) fuel forms which layers pyrolitic graphite and SiC (for the TRISO) around the fissile fuel kernels thus providing barriers to fission product retention within the fuel. The historic and most common porous host matrix is graphite. Such a fuel was developed as early nuclear thermal propulsion rockets with good success. This FCM fuel has the attribute of having both a primary fission product barrier (the TRISO fuel particle) and a secondary barrier being the SiC matrix. This combination thus provides two rugged barriers to fission product release. The SiC matrix of the known FCM™ fuel is fabricated through a Transient Eutectic-Phase (TEP) process whereby rare earth oxides are utilized to reduce the sintering temperature and pressure required to achieve full density for the SiC matrix. As taught in U.S. Pat. No. 9,299,464 B2 and 2017/0025192 A1 this process is essential in allowing a process window for which the fragile TRISO particles will not be crushed and thereby rendered ineffective in a fuel application. However, while the standard FCM product is considered robust for application temperatures up to 1850° C., above that temperature unacceptable SiC matrix degradation occurs due to instability of TEP SiC. Moreover, for application in systems such as nuclear thermal rocket engines the reaction between SiC and hot hydrogen is unacceptable. In order to move into a higher performance regime, a higher temperature ultra-high temperature ceramic (UHTC) that replaces the SiC matrix of the microencapsulated fuel is put forward. Typical UHTC's and their maximum application temperatures are provided in the table below. Of those materials listed zirconium carbide has a number of attractive features as an ultra-high temperature fuel matrix, though has historically been very difficult to process, requiring temperature and pressure well in excess of that which would crush modern TRISO fuel microencapsulation. The present invention provides a process to fabricate a zirconium carbide matrix microencapsulated fuel at conditions favorable to the use of TRISO fuel. Melt or Decomp.CrystalDensityTemperatureMaterialFormulastructure(g/cm3)(° C.)Niobium nitrideNbNCubic8.4702573Tantalum nitrideTaNCubic14.302700Vanadium carbideVCCubic5.772810Silicon carbideSiCCubic3.212820Zirconium nitrideZrNFCC7.292950Titanium nitrideTiNFCC5.392950Tantalum borideTaB2HCP12.543040Titanium carbideTiCCubic4.943100Titanium borideTiB2HCP4.523225Zirconium borideZrB2HCP6.103245Hafnium borideHfB2HCP11.193380Hafnium nitrideHfNFCC13.93385Zirconium carbideZrCFCC6.563400Niobium carbideNbCCubic7.8203490Tantalum carbideTaCCubic14.503768Hafnium carbideHfCFCC12.763958 The present invention provides the concept for a zirconium-carbide-matrix, ultra-high-temperature ceramic matrix fuel designed for advanced nuclear application. As envisioned, in comparison with standard FCM fuel which would achieve a nominal specific impulse in the range of 500-600 s, the use of ZrC-based or pure ZrC matrix UHTC FCM fuel would achieve in the range of 700-850 s. Application of this fuel includes nuclear rocket engines and systems requiring fuel of limited fission product release to operate at temperatures in excess of 2500° C. Use of ZrC matrix UHTC FCM could incorporate TRISO of standard or more rugged SiC micropressure vessels for short durations in the temperature range of 2200-2400° C., 2 hr time periods. Advanced microencapsulation whereby ZrC shells replace the SiC microencapsulation of the TRISO can be considered for longer life or higher temperature application. The TRISO containing ZrC is known to the literature (i.e. TRIZO), displaying similar crush strength to standard modern TRISO. The critical step towards achieving fabrication of the ZrC matrix UHTC FCM is the ability to consolidate a near full density matrix of ZrC while not compromising the function of the entrained second phase fissile fuel: to not crush, deform, or substantially react layers. In the case of a SiC (or ZrC) TRISO microencapsulation this means consolidation without rupture of a significant (<10 ppm) number of the SiC (or ZrC) protective shell layers. This is accomplished through suppression of the normal pressures and temperatures required for sintering of zirconium carbide. In addition to a low failure fraction of TRISO particles a measure of success for the matrix is to achieve near full density without interconnected porosity. As described, two methods have achieved acceptable levels of success in producing ZrC matrix UHTC FCM: A) Transient Eutectic-Phase Processing, B) Hydrogen Aided Sintering. 1 Microencapsulated fuel 1A Fissile fuel kernel 1B Outer pyrolitic carbon layer of microencapsulated fuel 1C SiC or alternate UHTC layer of microencapsulated fuel 1D Inner pyrolitic carbon layer of microencapsulated fuel 1E Buffer graphitic layer of microencapsulated fuel 2 Ceramic fuel sleeve 3 FCM mixture to be cold pressed 3A FCM constituent mixture: Zr and C powder, microencapsulated fuel, silica, aluminum oxide, and/or neutron poison rare earth oxides. 3B FCM constituent mixture: Zr and C powder, yttrium oxide, aluminum oxide, and neutron poison rare earth oxide. FIG. 1 provides a schematic similar to the known fully ceramic microencapsulated (FCM.) Whereby the known FCM utilizes SiC powder as a major matrix constituent, FIG. 1 portrays a fuel that is comprised of the fissile-fuel containing microencapsulation, in this case depicted as a Tri-Isotropic (TRISO) particle (item 1.) The new ZrC-matrix UHTC FCM fuel is demonstrated with acceptable matrix density and encapsulation integrity, post-processing, as achieved by the following means: Transient Eutectic-Phase Approach: Utilizing a combination of kinetic ball milling and high-shear milling to combine a certain volume fraction of ZrC powder and small percentage of SiC and oxide (such as Al2O3 and Y2O3) powders. This combination of ZrC, SiC and oxide powders form the dense matrix of this UHTC microencapsulated fuel. The compact of FIG. 1, forming the UHTC-FCM are fabricated at pressures not exceeding 20 MPa and temperatures not exceeding 2000° C. to attain a continuous, low porosity, ZrC matrix surrounding TRISO particles which remain unbroken and intimately bonded with the matrix following processing. The amount of oxide eutectic aids in the starting powder mix for processing the UHTC FCM fuel is up to 3 weight percent. The amount of SiC in the starting powder mix is up to 30 weight percent. Specifically, the transient eutectic phase (TEP) SiC mixture is comprised using 94% SiC, 3.9% Al2O3, 2.1% Y2O3 by mass. The density was critically sensitive to both amount and ratio of rare earth additives. The SiC powder used were either 35 nm or 85 nm nanophase powder produced by chemical vapor deposition process. The TEP SiC mixture was mixed with milling media, dried, deagglomerated and re-dispersed in atmosphere prior to use. The feedstock material consists of powders sourced from commercial vendors and processed under typical methodologies found in ceramic powder forming and sintering. The TEP SiC mixture was added to ZrC in ratios of ZrC with 10 wt % TEP SiC mixture and re-mixed as previously described. The feedstock powder is mixed with a proprietary set of dispersants, binders, flow plasticizers and release agents, which assist in rheological properties needed for forming operations. Sintering was conducted inside graphite tooling, configured for ˜10 mm diameter. Green bodies are formed in-die by loading the powder mixture directly into prepared graphite tooling. A cylindrical graphite die with a cylindrical cavity was lined with graphite foil. This conducts heat into the pellet and provides a release interface for the consolidated pellet. The pellet is formed by pouring the ZrC-based powder, followed by compaction by spark plasma sintering (SPS) for 10 minutes at 20 MPa at room temperature during the vacuum cycle. Before sintering the pressure was reduced to 10 MPa. The applied pressure was limited in order to establish processing conditions compatible with TRISO particles, which fail at low pressures at room temperature. Sintering temperatures of 1875° C. for 10 minutes. After sintering, the ZrC-10% TEP SiC mixture made into solid pellets. The pellets achieved 93% theoretical density. Hydrogen Aided Reaction Sintering: Utilizing a non-stoichiometric mixture of ZrC powder, ZrH and carbon powder the UHTC FCM ZrC matrix takes advantage of enhanced diffusion in a sub-stoichiometric ZrC and the decomposition of ZrH at approximately 900° C. In the absence of hydride decomposition the temperature and pressures were in excess of 2000° C. and 60 MPa with <95% theoretical density. With the addition of percent levels of ZrH the compact achieves near full density at temperatures under 1800° C. Powder handling and direct current sintering is carried out in a similar fashion to the Transient Eutectic-Phase Approach. Pressures not exceeding 20 MPa and temperatures in the 1650-1800° C. range produce a dense matrix and rupture-free TRISO microencapsulations. ZrH additions up to 10 weight percent by mass are demonstrated effective with free carbon in the range of 0.1 to 4% by mass.
	description	In order to improve performance such as the quantity of the current and response speed, the inventors of the present invention have studied techniques for optimizing the height of a barrier and the space-charges density by examining potentials dispersed between a first electrode film formed on a substrate and an X-ray detection layer mainly consisted of amorphous selenium, and potentials dispersed between a second electrode formed on the X-ray detection layer and the X-ray detection layer along with materials for the first electrode. The inventors fabricated a two-dimensional X-ray detection plate comprising semi-insulating charge transport layers with different thicknesses, which are formed on a TFT panel having a plurality of capacitors, thin film transistors (TFTs) and first electrode films formed thereon, and an X-ray detection layer mainly consisted of amorphous selenium and a second electrode film formed in a two-dimensional matrix. The inventors compared the resolutions of X-ray images that depend on the thicknesses of the semi-insulating charge transport layers. An embodiment of an X-ray detector according to the invention will be described first. For example, an X-ray detector is used in which ITO, diantimony trisulfide, amorphous selenium and gold are used on a glass substrate as a first electrode film, a charge transport layer, an X-ray detection layer and a second electrode film, respectively. However the present invention is not limited to this example. Stainless steel boats respectively loaded with diantimony trisulfide, selenium and gold were placed in a vacuum chamber of a vacuum deposition apparatus. A substrate made of glass having a first electrode film made of ITO formed in advance was transported into the vacuum chamber. After evacuating the vacuum chamber to a predetermined pressure, the diantimony trisulfide was heated with a resistance heating element to emit a vapor of diantimony trisulfide in the vacuum chamber, thereby forming a charge transport layer with a 3 xcexcm thick diantimony trisulfide thin film. The evaporation of diantimony trisulfide was then stopped, and selenium was similarly heated to emit a vapor of selenium in the vacuum chamber, thereby forming an X-ray detection layer with 500 xcexcm thick amorphous selenium thin film on the surface of the charge transport layer. The evaporation of selenium was then stopped, and gold was heated to emit a vapor of gold in the vacuum chamber, thereby forming a second electrode film with 0.1 xcexcm thick gold film on the surface of the X-ray detection layer. The substrate was then removed from the vacuum chamber. Reference numeral 31 as shown in FIG. 1 represents an X-ray detection plate according to a first embodiment of the invention obtained through the above-described steps. A first electrode film 12, a charge transport layer 13, an X-ray detection layer 14 and a second electrode film 15 are formed in the same order on a substrate 11. A power supply 20 was connected between the first electrode film 12 and second electrode film 15 of the X-ray detector 31 to apply a voltage, thereby measuring electrical characteristics of the same. FIG. 3 shows the result of the measurement. It would be understood that no current flows when a negative voltage is applied to the second electrode film and that a current flows when a positive voltage is applied. For the purpose of comparison, an X-ray detection plate 32 having a structure as shown in FIG. 2s was fabricated by forming an X-ray detection layer 14 made of amorphous selenium directly on the surface of a first electrode film 12 made of ITO and forming a second electrode film 15 consisted of a gold film directly on the surface of the X-ray detection layer 14. The X-ray detection plate 32 has no charge transport layer. A measurement of the electrical characteristics of the element 32 indicated that a current flows in both positive and negative directions as shown in FIG. 4. Based on the waveform of the current, the X-ray detection plate 32 shown in FIG. 2a can be represented by an equivalent circuit in which two diodes 41 and 42 are inverse-parallel connected as shown in FIG. 7b. The inverse-parallel connected circuit of the diodes 41 and 42 is regarded as physical properties of amorphous selenium. Then, a first electrode film 12 made of ITO, a charge transport layer 13 mainly consisted of diantimony trisulfide and a second electrode film 15 consisted of a gold thin film were formed in the same order on a substrate 11 made of glass to fabricate an X-ray detection plate 33 having no X-ray detection layer as shown in FIG. 2b. A measurement of the electrical characteristics of the X-ray detection plate 33 indicated resistive characteristics as shown in FIG. 5. The specific resistance was 108 xcexa9cm. Therefore, an equivalent circuit of the X-ray detection plate 33 shown in FIG. 2b can be represented by a resistive component 44 as shown in FIG. 7c. The resistive component 44 is regarded as physical properties of diantimony trisulfide layer. The X-ray detection plate 31 according to the first embodiment has the inverse-parallel connected circuit of diodes 41 and 42 shown in FIG. 7b and the resistive component 44 shown in FIG. 7C because it has the X-ray detection layer 14 made of amorphous selenium and the charge transport layer 13 mainly consisted of diantimony trisulfide which are stacked on one another. Further, since the X-ray detection plate 31 according to the first embodiment as a whole exhibits diode characteristics as shown in FIG. 3, the X-ray detection plate 31 consequently has an equivalent circuit in which a inverse-parallel connected circuit of diodes 41 and 42, a resistive component 44 and a reverse-blocking diode 43 are connected in series as shown in FIG. 7a. The anode of the reverse-blocking diode 43 faces the second electrode film 15, and the cathode of the same faces the first electrode film. A comparison between the structure of the X-ray detection plate 31 according to the first embodiment and the structures of the X-ray detection plates 32 and 33 shown in FIGS. 2A and 2B indicates that the reverse-blocking diode 43 represents the electrical characteristics of the interface between the X-ray detection layer 14 and charge transport layer 13. For the purpose of comparison, an X-ray detection layer 14 consisted of amorphous selenium was formed on a first electrode film 12 made of ITO, and a charge transport layer 13 mainly consisted of diantimony trisulfide was formed on the surface thereof, and a second electrode film 15 consisted of a gold thin film was formed on the surface of the charge transport layer 13 to fabricate an X-ray detection plate 34 as shown in FIG. 2c. The electrical characteristics of the X-ray detection plate 34 having such a structure are diode characteristics as shown in FIG. 6. However, the current flows in the direction opposite to that of the X-ray detection plate 31 according to the invention because the X-ray detection layer 14 and charge transport layer 13 are formed in the reverse order. FIG. 7d shows an equivalent circuit of the X-ray detection plate 34. An X-ray detector according to the invention will now be described. Reference numeral 57 in FIG. 9 represents an embodiment of an X-ray detector according to the invention. The X-ray detector 57 has an X-ray detection plate 40 which is an embodiment of the invention. FIG. 8 shows a sectional view of the X-ray detection plate 40. The X-ray detection plate 40 has an insulating substrate 81, and a plurality of charge storage elements 86 comprising a plurality of capacitors 87 and a plurality of thin film transistors (TFTs) 88 are formed on the insulating substrate 81. A plurality of first electrode films 82 are formed on the charge storage elements 86. The first electrode films 82 are electrically connected to the plurality of capacitors 87 respectively. The first electrode films 82 are insulated from each other, and a charge transport layer 83 consisted of an diantimony trisulfide thin film is formed on the surface thereof. An X-ray detection layer 84 consisted of an amorphous selenium thin film is formed on the charge transport layer 83, and a second electrode film 85 mainly consisted of gold is further formed on the surface of the X-ray detection layer 84. The charge transport layer 83 may be made of a substance other than diantimony trisulfide provided that it is a semi-insulating resistor whose specific resistance is between 106 xcexa9cm and 1012 xcexa9cm inclusive. FIG. 10 is an equivalent circuit diagram of the charge storage elements 86. The X-ray detector 57 according to the invention has a power supply 55, an X-ray irradiator 50 and a gate driver 90. The thin film transistors 88 is turned off by the gate driver 90, and an X-ray 5a is radiated by the X-ray irradiator 50 while a negative voltage applied to the second electrode film 85 by the power supply 55. When the second electrode film 85 is irradiated by the X-ray which has been transmitted by an object to be measured, signal charges in accordance with the object to be measured are generated in the X-ray detection layer 84. The signal charges are consisted of holes which are positive charges and electrons which are negative charges. A bias electrical field inclined in the direction of the thickness of the X-ray detection layer 84 is formed between the first electrode films 82 and the second electrode film 85 by the voltage applied by the power supply 55, and the signal charges generated in the X-ray detection layer 84 are moved by the bias electrical field toward the first electrode films 82 and the second electrode film 85 according to their polarities. The capacitors 87 are connected to the respective first electrode films 82 at one end thereof and are connected to a ground potential at the other end thereof. Since the thin film transistors 88 are off, the capacitors 87 are charged by a current that have flown as a result of the movement of the signal charges. The X-ray detector 57 according to the invention has a charge-to-voltage conversion circuit 89 and a display device 93. When the thin film transistors 88 are turned on by the gate driver 90, the high voltage ends of the capacitors 87 are connected to the charge-to-voltage conversion circuit 89, and the charge-to-voltage conversion circuit 89 converts the charges into voltage signals which are displayed on the display device 93. FIG. 9 is a schematic illustration of a configuration of the X-ray detector 57 shown in FIG. 8. The gate terminals of the thin film transistors 88 provided at each pixel on a row of the matrix are commonly connected to the gate driver 90. Amplifier circuits 91 are provided in the charge-to-voltage conversion circuit 89 in the same quantity as the plurality of rows of the matrix, and the drain terminals of the thin film transistors 88 on each column of the matrix are connected to the respective amplifier circuit 91. A signal charge input to each amplifier circuit 91 is converted into a voltage and output by the amplifier circuit 91 to a multiplexer 92. Signals output by the amplifier circuits 91 are sent by the multiplexer 92 to the image display device 93 pixel by pixel on each row and column at predetermined time intervals. An image enhancement circuit for image enhancement such as removal of noises is provided in the display device 93. The image enhancement circuit performs appropriate image processing, and the signals are reconstructed as a two-dimensional image which is in turn displayed on a display area of the display device 93. Then, xe2x80x9cdark currentxe2x80x9d, xe2x80x9csignal currentxe2x80x9d, xe2x80x9cfall timexe2x80x9d and xe2x80x9crise timexe2x80x9d were measured on the X-ray detection plate 31 according to the first embodiment. Conditions of measurement are following: 1. Dark Current A negative current was applied to the second electrode film 15 to generate an electrical field of 10 V/xcexcm in the X-ray detection plate 31, and a current obtained after leaving the plate in a dark place for ten minutes in such a state was measured as xe2x80x9ca dark currentxe2x80x9d. The dark current is preferably 100 pA/cm2 or less. 2. Signal Current After measuring the dark current, the second electrode film 15 was irradiated with an X-ray having a predetermined intensity from above with a negative voltage of the same magnitude as measurement of dark current applied thereto, and a current that flew through the X-ray detection plate 31 was measured when irradiated by the X-ray. The signal current is preferably 70 pA/cm2 or more. In order to stabilize the current, the current was measured when one minutes passed after the beginning of the irradiation with the X-ray, and the current was defined as xe2x80x9ca signal currentxe2x80x9d. Referring to conditions for the irradiation with an X-ray at this time, the voltage applied to the X-ray tube was set at 80 kV, and the quantity of the X-ray directed to the X-ray detection plate 31 was set at 1.8 R/min. 3. Fall Time When the irradiation with an X-ray is stopped after the measurement of the signal current, the current value decreases. The time spent before the current decreased to 10% of the dark current after the end of the irradiation with an X-ray was defined as xe2x80x9ca fall timexe2x80x9d. The fall time is preferably 0.1 sec. or less. 4. Rise Time When the signal current is measured by irradiating the plate with an X-ray after measuring the dark current, the current increases after the irradiation with an X-ray is started and stabilizes at a predetermined value (the magnitude of the signal current). The time spent before the current increased to 90% of the signal current after the beginning of the irradiation with an X-ray was defined as xe2x80x9ca rise timexe2x80x9d. The rise time is preferably 0.1 sec. or less. The following table shows results of such measurement on the X-ray detection plate 31 according to the first embodiment and on second through seventh embodiments of the invention and first through fifth comparative examples. [Second Embodiment] An X-ray detection plate according to a second embodiment of the invention was fabricated which had the same structure as that of the X-ray detection plate 31 of the first embodiment except that the first electrode film 12 of the X-ray detection plate 31 of the first embodiment was changed from an ITO thin film to a gold thin film, and measurement was carried out on the same contents as measured on the X-ray detection plate 31 of the first embodiment. [Third Embodiment] An X-ray detection plate according to a third embodiment of the invention was fabricated which had the same structure as that of the X-ray detection plate 31 of the first embodiment except that the first electrode film 12 of the X-ray detection plate 31 of the first embodiment was changed from an ITO thin film to an aluminum thin film, and measurement was carried out on the same contents as measured on the X-ray detection plate 31 of the first embodiment. [Fourth Embodiment] An X-ray detection plate according to a fourth embodiment of the invention was fabricated which had the same structure as that of the X-ray detection plate 31 of the first embodiment except that the thickness of the X-ray detection layer 14 mainly consisted of amorphous selenium of the X-ray detection plate 31 of the first embodiment was changed from 500 xcexcm to 1000 xcexcm, and measurement was carried out on the same contents as measured on the X-ray detection plate 31 of the first embodiment. [Fifth Embodiment] An X-ray detection plate according to a fifth embodiment of the invention was fabricated which had the same structure as that of the X-ray detection plate 31 of the first embodiment except that the thickness of the charge transport layer 13 mainly consisted of diantimony trisulfide of the X-ray detection plate 31 of the first embodiment was changed from 3 xcexcm to 0.01 xcexcm, and measurement was carried out on the same contents as measured on the X-ray detection plate 31 of the first embodiment. [Sixth Embodiment] An X-ray detection plate according to a sixth embodiment of the invention was fabricated which had the same structure as that of the X-ray detection plate 31 of the first embodiment except that the thickness of the charge transport layer 13 mainly consisted of diantimony trisulfide of the X-ray detection plate 31 of the first embodiment was changed from 3 xcexcm to 40 xcexcm, and measurement was carried out on the same contents as measured on the X-ray detection plate 31 of the first embodiment. [Seventh Embodiment] While diantimony trisulfide was used as the material of the charge transport layer of the X-ray detection plate 31 of the first embodiment, a charge transport layer of an X-ray detection plate of a seventh embodiment was formed by a cadmium zinc telluride thin film having a thickness of 3 xcexcm instead of diantimony trisulfide. The X-ray detection plate of the seventh embodiment had the same structure as that of the X-ray detection plate 31 of the first embodiment except the material of the charge transport layer, and measurement was carried out on the same contents as measured on the X-ray detection plate 31 of the first embodiment. [First Comparative Example] An X-ray detection plate as a first comparative example was fabricated by using a substrate 11 made of glass having a first electrode film 12 consisted of ITO formed thereon, forming an X-ray detection layer 13 made of amorphous selenium directly on the surface of the first electrode film 12 without forming the charge transport layer 13 and forming a second electrode film 15 consisted of a gold thin film with a thickness of 0.2 xcexcm on the surface of the same. The X-ray detection plate as the first comparative example had the same structure as that of the X-ray detection plate 31 of the first embodiment except that the charge transport layer 13 was not provided, and the X-ray detection plate as the first comparative example is also subjected to measurement of the same contents as measured on the X-ray detection plate 31 of the first embodiment. [Second Comparative Example] An X-ray detection plate as a second comparative example was fabricated which had the same structure as that of the X-ray detection plate of the first comparative example except that the first electrode film was consisted of an gold thin film instead of ITO, and measurement was carried on the same contents as measured on the X-ray detection plate 31 of the first embodiment. [Third Comparative Example] An X-ray detection plate as a third comparative example was fabricated which had the same structure as that of the X-ray detection plate of the first comparative example except that the first electrode film was consisted of an aluminum thin film instead of ITO, and measurement was carried on the same contents as measured on the X-ray detection plate 31 of the first embodiment. [Fourth Comparative Example] An X-ray detection plate as a fourth comparative example was fabricated which had the same structure as that of the first embodiment except that the charge transport layer was formed with a 3 xcexcm thick cadmium sulfide thin film instead of diantimony trisulfide, and measurement was carried on the same contents as measured on the X-ray detection plate 31 of the first embodiment. [Fifth Comparative Example] An X-ray detection plate as a fifth comparative example was fabricated which had the same structure as that of the first embodiment except that the charge transport layer was formed with a 3 xcexcm thick cerium oxide thin film instead of diantimony trisulfide, and measurement was carried on the same contents as measured on the X-ray detection plate 31 of the first embodiment. [Evaluation 1] As apparent from Table 1, the X-ray detection plates as the first through third comparative examples having no charge transport layer are not practical because holes from the first electrode can not be blocked and the dark current which is a sensor noise becomes very high. The X-ray detection plate as the fourth comparative example has a charge transport layer consisted of cadmium sulfide. Since cadmium sulfide has a specific resistance of 80xcexa9cm. It is lower than 106 xcexa9cm, and it has no function of blocking holes injected from the first electrode film, which increases the dark current. The X-ray detection plate as the fifth comparative example has a charge transport layer consisted of cerium oxide. Cerium oxide has a specific resistance of 105 xcexa9cm and it is less than 106 xcexa9cm. Although it exhibits diode characteristics, its function of blocking holes injected from the first electrode film is weak, which increases the dark current. Unlike the first through fifth comparative examples described above, in the case of the X-ray detection plates of the first through sixth embodiments, a diode formed at the interface between charge transport layer mainly consisted of diantimony trisulfide and the X-ray detection layer made of amorphous selenium blocks the injection of holes into the X-ray detection layer from the first electrode film and does not block holes injected into the charge transport layer from the X-ray detection layer and charges injected into the X-ray detection layer from the charge transport layer. Thus, noise components can be reduced, and response can be improved. The seventh embodiment had preferable results although zinc telluride cadmium is used instead of diantimony trisulfide. Therefore, an X-ray detection plate according to the invention can be fabricated using substances other than diantimony trisulfide as long as the charge transport layer is a semi-insulating resistor whose specific resistance is between 106 xcexa9cm and 1012 xcexa9cm inclusive and the junction between the charge transport layer and the X-ray detection layer has characteristics of a diode whose cathode is the charge transport layer side and whose anode is the X-ray detection layer side. It was found that no reverse blocking diode is formed when the diantimony trisulfide content of the charge transport layer according to the invention is 91 weight % or less. As a result of an experiment, electrical characteristics as shown in FIG. 3 are achieved when 95 weight % or more of diantimony trisulfide is included in the charge transport layer. The purity of selenium in the an X-ray detection layer in such a case was 99.99 weight %. Referring to impurities other than selenium in an X-ray detection layer, it has been found that As, Te, Mg, Si, Fe, Al, Cu, Ag, Cl and Na exist. As and Te do not affect electrical characteristics when their content is 10 weight % or less. Referring to selenium for forming an X-ray detection layer, selenium with high purity may be used as a deposition source. Alternatively, an amorphous X-ray detection layer including tellurium or an X-ray detection layer including arsenic may be provided by using an alloy of selenium and tellurium or an alloy of selenium and arsenic as a deposition source and selenium as a main component. Referring to other impurities in an X-ray detection layer, it is assumed that they do not affect electrical characteristics if the content is 1 weight % or less. [Eighth Embodiment] A two-dimensional X-ray detector as shown in FIGS. 8 and 9 was fabricated, and the spatial frequency characteristics or MTF (modulation transfer function) that serve as an index of resolution was measured. ITO was used as the first electrode film; diantimony trisulfide with a thickness of 3.0 xcexcm was used as the charge transport layer; amorphous selenium with a thickness of 500 xcexcm was used as the X-ray detection layer; and gold was used as the second electrode layer. The pixel size of the two-dimensional X-ray detector was 150 xcexcm. MTF was measured using lead slits with slits width in the range from 10 xcexcm to 20 xcexcm, and the data was measured with the slits inclined relative to the direction of the columns of the two-dimensional X-ray detector at an angle in the range from about 1xc2x0 to 2xc2x0. [Sixth Comparative Example] A two-dimensional X-ray detector was fabricated which had the same structure as that of the eighth embodiment except that the thickness of diantimony trisulfide was 0.07 xcexcm, and MTF of the same was measured. [Evaluation 2] As shown in FIG. 11, the MTF of the sample as the eighth embodiment is close to a theoretical value, which indicates that there is no reduction in resolution. On the contrary, the MTF of the sample as the sixth comparative example is much smaller than a theoretical value, which indicates that there is a reduction in resolution. When two-dimensional X-ray detectors similar to the eighth embodiment are fabricated using the structures shown in the fourth and fifth comparative examples and X-ray images are obtained, the resultant images have unclear contrast and include after-images, which indicates that no clear images can not be obtained. As described above, when the second electrode film of an X-ray detection plate according to the invention is irradiated with an X-ray, the X-ray is transmitted by the second electrode film to enter the X-ray detection layer mainly consisted of amorphous selenium, and carriers which are pairs of electrons and holes are generated in the X-ray detection layer by the energy of the X-ray. In this case, when the X-ray is radiated with voltages applied between the first and second electrode films, each of the carriers generated in the X-ray detection layer is moved by the electrical fields and collected by the first and second electrode films. Referring to the polarities of the voltages applied between the first and second electrode films, when the voltage applied to the second electrode film is lower than the voltage applied to the first electrode film, electrons are collected by the first electrode film and holes are collected by the second electrode film by the action of the electrical fields. In the X-ray detection plate according to the invention, a charge transport layer formed with a semi-insulating resistor is provided between the first electrode film at the positive voltage and the X-ray detection layer at the negative voltage. This charge transport layer is in contact with the x-ray detection layer mainly consisting of amorphous selenium, and a diode whose anode side is the x-ray detection layer side and whose cathode is the charge transport layer side. This diode is formed between the X-ray detection layer and the charge transport layer caused by the physical property of the charge transport layer. Since a diode have rectification characteristics, holes are prevented from being injected into the X-ray detection layer by the diode even when the holes are injected into the charge transport layer from the first electrode film. As a result, the dark current that acts as dark noises can be reduced by two digits without reducing the mobility and the life of carriers. The diode does not hinder the movement of holes generated in the X-ray detection layer to the second electrode film. Further, it does not hinder the movement of electrons from the first electrode film into the charge transport layer. Therefore, only noise components are reduced, and the life after repeated use and response can be improved to improve the sensitivity of the X-ray detector consequently. When the charge transport layer of an X-ray detector according to the invention is semi-insulating, there is a significant advantage in that the dispersion of carriers which have entered the charge transport layer can be prevented to prevent any reduction of resolution. It has been empirically revealed that the semi-insulating charge transport layer must have a thickness of 0.01 xcexcm or more as a lower limit, and the upper limit of the thickness is 50 xcexcm for reasons including peeling of the film. Further, a thickness in the range from 0.1 xcexcm to 5 xcexcm inclusive is especially preferable because it will provide excellent spatial frequency characteristics. An X-ray detection plate according to the invention and an X-ray detector utilizing the X-ray detection plate will allow an X-ray to be detected with a high signal-to-noise ratio. A two-dimensional X-ray detector according to the invention is advantageous as a two-dimensional X-ray photographic apparatus that serves various industrial purposes beside medical applications because it provides images of high quality with high resolution.
	abstract	In an electronic design automation technique for optical proximity correction, a mask is represented by a function with an exact analytical form over a mask region. Using the physics of optical projection, a solution based on a spatial frequency analysis is determined. Spatial frequencies above a cutoff are determined by the optical system do not contribute to the projected image. Spatial frequencies below this cutoff affect the print (and the mask), while those above the cutoff only affect the mask. Frequency components in the function below this cutoff frequency may be removed, which will help to reduce computational complexity.
	claims	1. A vibratory transducer for a fluid flowing in a pipe, comprising:an essentially straight flow tube communicating with the pipe for conducting the fluid, said flow tube being operable to vibrate;an antivibrator fixed to said flow tube, said antivibrator extending essentially parallel to said flow tube;an excitation assembly acting on said flow tube for vibrating said flow tube; anda sensor arrangement for sensing vibrations of said flow tube, said sensor arrangement being adapted to sense both torsional vibration and flexural vibrations of said flow tube wherein:said sensor arrangement includes a sensor coil fixed to said antivibrator and an armature fixed to said flow tube; andsaid sensor coil is magnetically coupled to said armature such that a variable measurement voltage influenced by rotational and lateral relative motions between said flow tube and said antivibrator is induced in said sensor coil. 2. The vibratory transducer as claimed in claim 1, further comprising:a transducer case coupled to said flow tube. 3. The vibratory transducer as claimed in claim 2, further comprising:a transducer case coupled to said flow tube wherein:said transducer case is fixed to inlet and outlet tube sections. 4. The vibratory transducer as claimed in claim 1, wherein:said flow tube communicates with the pipe via an inlet tube section, ending in an inlet end of said flow tube, and via an outlet tube section, ending in an outlet end of said flow tube. 5. The vibratory transducer as claimed in claim 1, wherein:said sensor is adapted to sense both, torsional vibrations and flexural vibrations simultaneously. 6. The vibratory transducer as claimed in claim 1, wherein:in operation said flow tube performs, at least intermittently, torsional vibrations about an imaginary longitudinal flow-tube axis. 7. The vibratory transducer as claimed in claim 6, wherein:in operation antivibrator vibrates, at least partially, out of phase with said torsionally vibrating vibration flow tube. 8. The vibratory transducer as claimed in claim 6, wherein:in operation said flow tube performs, at least intermittently, flexural vibrations about an imaginary longitudinal flow-tube axis. 9. The vibratory transducer as claimed in claim 6, wherein:in operation said flow tube performs flexural vibrations about an imaginary longitudinal flow-tube axis simultaneously with said torsional vibrations. 10. The vibratory transducer as claimed in claim 9, wherein:said sensor coil is adapted to sense both, torsional vibrations and flexural vibrations simultaneously. 11. The vibratory transducer as claimed in claim 10, wherein:the sensor coil is fixed to said antivibrator outside all principal axes of inertia of said sensor arrangement. 12. The vibratory transducer as claimed in claim 1, wherein:in operation said flow tube performs, at least intermittently, flexural vibrations about an imaginary longitudinal flow-tube axis. 13. The vibratory transducer as claimed in claim 1, wherein:said antivibrator is essentially straight. 14. The vibratory transducer as claimed in claim 13, wherein;said antivibrator is connected to said flow tube as to be essentially coaxial with said flow tube. 15. The vibratory transducer as claimed in claim 14, wherein:said antivibrator is in the form of a tube. 16. The vibratory transducer as claimed in claim 1, wherein:said antivibrator is in the form of a tube. 17. The vibratory transducer as claimed in claim 1, wherein:the sensor coil is fixed to said antivibrator outside all principal axes of inertia of said sensor arrangement. 18. A meter for measuring a viscosity of a fluid flowing in a pipe, said meter including a vibratory transducer, comprising:an essentially straight flow tube communicating with the pipe for conducting the fluid, said flow tube being operable to vibrate;an antivibrator fixed to said flow tube, said antivibrator extending essentially parallel to said flow tube;an excitation assembly acting on said flow tube for vibrating said flow tube; anda sensor arrangement for sensing vibrations of said flow tube, said sensor arrangement being adapted to sense both torsional vibrations and flexural vibrations of said flow tube wherein:said sensor arrangement includes a sensor coil fixed to said antivibrator and an armature fixed to said flow tube; andsaid sensor coil is magnetically coupled to said armature such that a variable measurement voltage influenced by rotational and lateral relative motions between said flow tube and said antivibrator is induced in said sensor coil. 19. A vibratory transducer for a fluid flowing in a pipe, comprising:an essentially straight flow tube communicating with the pipe for conducting the fluid, said flow tube being operable to vibrate;an antivibrator fixed to said flow tube, said antivibrator extending essentially parallel to said flow tube:an excitation assembly acting on said flow tube for vibrating said flow tube; anda sensor arrangement for sensing vibrations of the flow tube said sensor arrangement being adapted to sense both torsional and flexural vibrations of said flow tube, wherein:said sensor arrangement includes a sensor coil fixed to said flow tube and an armature fixed to said antivibrator; and said sensor coil is magnetically coupled to said armature such that a variable measurement voltage influenced by rotational and lateral relative motions between said flow tube and said antivibrator is induced in said sensor coil. 20. The vibratory transducer as claimed in claim 19, wherein:said sensor coil is fixed to said antivibrator outside all principal axes of inertia of said sensor arrangement. 21. The vibratory transducer as claimed in claim 19, wherein:in operation said flow tube performs, at least intermittently, torsional vibrations about an imaginary longitudinal flow-tube axis. 22. The vibratory transducer as claimed in claim 21, wherein:in operation said flow tube performs, at least intermittently, flexural vibrations about an imaginary longitudinal flow-tube axis. 23. The vibratory transducer as claimed in claim 22, wherein:in operation said flow tube performs flexural vibrations about an imaginary longitudinal flow-tube axis simultaneously with said torsional vibrations. 24. The vibratory transducer as claimed in claim 23, wherein:said sensor coil is adapted to sense both, torsional vibrations and flexural vibrations simultaneously. 25. The vibratory transducer as claimed in claim 24, wherein:the sensor coil is fixed to said antivibrator outside all principal axes of inertia of said sensor arrangement. 26. The vibratory transducer as claimed in claim 19, wherein:in operation said flow tube performs, at least intermittently, flexural vibrations about an imaginary longitudinal flow-tube axis. 27. The vibratory transducer as claimed in claim 19, wherein:said antivibrator is essentially straight. 28. The vibratory transducer as claimed in claim 27, wherein:said antivibrator is connected to said flow tube as to be essentially coaxial with said flow tube. 29. The vibratory transducer as claimed in claim 28, wherein:said antivibrator is in the form of a tube. 30. The vibratory transducer as claimed in claim 19, wherein:said antivibrator is in the form of a tube. 31. The vibratory transducer as claimed in claim 19, wherein:said sensor coil is adapted to sense both torsional vibrations and flexural vibrations simultaneously. 32. The vibratory transducer as claimed in claim 19, further comprising:a transducer case coupled to said flow tube. 33. The vibratory transducer as claimed in claim 19, wherein:said flow tube communicates with the pipe via an inlet tube section, ending in an inlet end of said flow tube, and via an outlet tube section, ending in an outlet end of said flow tube. 34. The vibratory transducer as claimed in claim 33, further comprising:a transducer case coupled to said flow tube, wherein:said transducer case is fixed to inlet and outlet tube sections. 35. A meter for measuring a viscosity of a fluid flowing in a pipe, said meter including a vibratory transducer comprising:an essentially straight flow tube communicating with the pipe for conducting the fluid, said flow tube being operable to vibrate;an antivibrator fixed to said flow tube, said antivibrator extending essentially parallel to said flow tube;an excitation assembly acting on said flow tube for vibrating said flow tube; anda sensor arrangement for sensing vibrations of the flow tube said sensor arrangement being adapted to sense both torsional and flexural vibrations of said flow tube, wherein:said sensor arrangement includes a sensor coil fixed to said flow tube and an armature fixed to said antivibrator; andsaid sensor coil is magnetically coupled to said armature such that a variable measurement voltage influenced by rotational and lateral relative motions between said flow tube and said antivibrator is induced in said sensor coil.
053393392	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS This industrial site 5 has not shown automatic installations, whose operation is checked by sensors 10 distributed over the site 5 and which are grouped around the collection or reading points 12. Equipments 11 having a certain operating state are also linked with these collection points and can be in the form of valves, switches, etc. Each collection point 12 is pinpointed on the site 5 and indicated by a label carrying an identification bar code of the said point. In order to locate a collection point 12, the site 5 can e.g. be divided into levels, level 1 corresponding to a building 14, level 2 to part of the building designated as a cell 16, level 3 to part of the cell designated as a unit 18, whereby the latter can have several collection points 12. In the drawing, the building 14 is subdivided into two cells 16 separated by a mixed line. The cells 16 are subdivided into units 18 by broken lines. The site 5 also has at least one control room 20 in which is installed at least one central computer 22 connected to a radiofrequency transceiver 24. The computer 22 can be of the microcomputer type. Various data are contained in a general file kept up to date after each round. This file recorded in the central computer 22 contains all the collection points 12 to which are allocated the identification references permitting their location. The file also contains the list of sensors 10 and equipments 11 grouped around the collection points 12. These sensors 10 and equipments 11 are indicated by identification references. This list in the file is completed by various informations, e.g. the type of sensor (thermal, electric, sensitive to radiation, sensitive to fumes) or equipment (valve, switch, elevator), the geographical location, the normally expected characteristics or values, tolerance thresholds, the checks to be carried out on the data collected during the rounds, the values obtained during the different rounds already performed, the time and date of these readings, the measuring units used and any other information making it possible to carry out an effective inspection, such as e.g. assistance comments on the decision regarding each of the sensors and equipments. Inter alia, this file makes it possible to display on a video monitor of a plan of the industrial site equipped with all the collection points, the sensors and equipments to be monitored. Before starting on his round, the watchman chooses from within the central file a sequence of collection points 12, sensors 10 to be checked and equipments to be checked and/or whose operating state is to be modified. This sequence is recorded in the central computer 22 and is defined by the performance course of the round on the site 5. Recording also takes place of the informations (or part thereof, but at least the reference values, historical values corresponding e.g. to the last five readings, tolerance thresholds and assistance comments on the decision) concerning the collection points 12, the sensors 10 and the equipments 11 to be monitored. Standard paths provided with information relating thereto are also available. They make it unnecessary for the watchman to redefine his complete path when starting out on each occasion. These standard paths can be modified at random. When the sequence or combination has been established, a theoretical time necessary for the path between each collection point 12 is defined. This time is recorded in a memory of the central computer 22 for each path between two collection points 12. Each round starts from the control room 20, where the watchman copies again the sequence established, as well as the informations relating thereto in a memory of a portable microcomputer 26 equipped with a screen associated with a radiofrequency transceiver 28. This microcomputer 26 is also equipped with a wand reader for reading a bar code 30. On the basis of said data, the microcomputer 26 carried during the round guides the watchman by indicating to him towards which collection point 12 he should move, together with the equipments or sensors 10 to be checked. At each passage to a collection point 12, the watchman reads the bar code carrying the identification reference of the point using the wand reader 30. This bar code reading constitutes a validation of the passage of the watchman to the collection point 12. The microcomputer 26 records the reading and allocates thereto a passage time table by means of an internal clock. Moreover, the microcomputer 26 displays on the screen a message confirming to the watchman that the collection point is indeed that provided in the sequence constituting the round. In the opposite case, the display on the screen of the portable microcomputer indicates the collection point normally provided. At this stage the operator has the choice between confirming the modification of the instruction provided by validating said information on the keyboard or of moving to the displayed collection point and carrying out again in situ an identification reading by reading the bar code. At each reading of an identification reference of the collection point, a pinpointing or location signal is transmitted by the transmitter 28 connected to the portable microcomputer 26 to the receiver 24 connected to the central computer 22. The effect of the reception of the signal is to trigger an internal clock within the computer 22. If the following validation has not taken place when the theoretical time between two validations and which has been defined beforehand has elapsed, an alarm is given by the central computer 22. Initially said alarm can be a signal transmitted by the transmitter 24 associated with the central computer 22 to the receiver 28 associated with the portable microcomputer 26. This signal triggers a sound and/or visual transmission or the display of a message on the screen of the microcomputer 26. The watchman must then reply by a message which he enters into the microcomputer 26 and which is transmitted by radiofrequency transmission to the computer 22. If no response is received, the computer 22 can alert an emergency team, which will intervene as quickly as possible when the location of the watchman becomes known. At each collection point 12, the watchman collects the informations supplied by the sensors 10 and records them in a memory of the portable microcomputer 26. He also carries out the checks and/or operating state changes of the equipments 11 and records information relating to said equipments. For each sensor 10 or equipment 11, the microcomputer 26 makes a comparison between said informations and the prerecorded values corresponding to a normal operation of the installations. This comparison and also the definition of tolerance thresholds makes it possible to detect any operational abnormality. Following each acquisition of informations concerning the sensors 10 or equipments 11, the watchman must carry out a validation. When the validated value is non-standard, via the transmitter 28, the microcomputer 26 transmits a message to the central computer 22. As a function of the defective sensor 10 and the type of abnormal condition, said central computer alerts a maintenance team, which can operate rapidly and effectively. Optionally, the central computer 22 can automatically interrupt certain electrical or other circuits. When an abnormal operating state is detected, the watchman can display historical informations stored in the portable microcomputer 26 and which concern measurements performed during preceding rounds. The portable microcomputer 26 also displays assistance comments on the decision and, as a function of the particular case, the watchman can change the passage sequence to the collection points 12, check sensors 10 or equipments 11 not planned during the definition of the round, or even interrupt his round, whilst still keeping the central computer 22 informed via the radiofrequency link. For each checked sensor 10 or equipment 11, the watchman is responsible for recording comments on the operation of the installations. These comments favour an effective preventative maintenance, because they make it possible to avert incidents. For example, a maintenance team alerted by these comments can replace a particular part before it deteriorates and in fact as soon as it has deficiency symptoms. At the end of he round, the informations read on the sensors 10 and contained in a memory of the portable microcomputer 26 are recorded in a memory of the central computer 22 in such a way that they can be processed there, whilst the central file is also updated. The processing can consist of statistics concerning a large number of rounds, evolutions of informations supplied by the sensors, or an analysis of variations in the reaadings of the sensors. If desired, a written paper report of all the informations can be obtained. The process according to the invention makes it possible to follow several watchmen from the same control room. The permanent link between the central computer and the portable microcomputer enables decisions to be taken rapidly and effectively. As a result of this link and the informations contained in the portable microcomputer, the watchman can analyze abnormal situations and act as a consequence thereof. He is responsible for his actions, whilst still being controlled by the central computer.
051401657	abstract	A vessel for solidifying radioactive waste pellets includes a vessel body, an inner lid mounted within the vessel body and fixedly secured to an upper portion of the vessel body, and a device for preventing the pellets from floating fixedly secured one end thereof to the inner lid. The inner lid has an opening formed at a generally central portion thereof, and the pellet float prevention device is extended into the opening of the inner lid to define gaps therebetween allowing the passage of a solidifying material in the state of a liquid or a slurry therethrough but preventing the passage of the radioctive waste pellets therethrough. The pellet prevention device, when receiving a downward urging force, is bent downward to enlarge the gaps therebetween for allowing the radioactive waste pellets to pass therethrough. The pellet float prevention device is returned by a resilient restoring force to its initial position when the downward urging force is released. The pellet float prevention device comprises a plurality of coil springs fixedly secured to the inner lid in a radial manner, and some of the plurality of coil springs extend to an area close to the center of the opening in the inner lid. The coil springs are extended in such a manner that the axis of each of the coil springs is displaced a predetermined angle from the center of the opening in the inner lid.
	claims	1. A process for destruction of organic contaminants in dredged material for the formulation of a beneficial end product wherein the process is sequentially set forth:(a) sorting out particles greater than ¼ inch in size;(b) diluting the remaining material with water;(c) separating out sand, gravel and non-contaminated organic matter;(d) adding a reductive agent to the remaining material;(e) separating out particles from the remaining material such that about 10% of the dredged material remains;(f) adding an oxidizing agent to the remaining material from step (e);(g) adjusting the dwell time and amount of oxidizing agent added on the basis of total organic carbon (TOC) and chemical oxygen demand (COD) to the remaining material;(h) separating out particles 60 microns or less from the remaining material;(i) adding a reducing agent to the remaining material;(j) adding an oxidizing agent to particles 60 microns or less in size in the remaining material;(k) adjusting the pH in the remaining material;(l) separating out particles 60 microns or less in size from the remaining material;(m) adding a reducing agent to the particles from step (l) and dewatering;(n) separating the remaining material into:(1) filtrate; and(2) filter cake,wherein said filtrate is recycled to the above process. 2. The method of claim 1 further comprising providing a source of contaminated sediment. 3. The process of claim 1 wherein a site survey is conducted to determine the types of contamination involved.
	summary
	abstract	A column assembly of a radionuclide generator includes a column that retains a parent radionuclide that spontaneouosly decays to a relatively short-lived daughter radionuclide. A fluid path extends from an inlet port to the column and then to an outlet port and allows daughter radionuclide to be eluted from the radionuclide generator for use. Improved retention of parent radionuclide in the column is accomplished by preventing fluid from entering the flow path in a liquid state, such as during sterilization. Proper column chemistry is also promoted by preventing excess moisture from coalescing in the column, which may promote a higher and/or more reliable yield of daughter radionuclide from a radionuclide generator.
	description	The invention relates to an adjusting device and method for adjusting imaging parameters, such as in particular the X-ray dose, the tube current, the tube voltage, the pulse length and the filter settings of an X-ray apparatus in order to minimize the radiation load on a patient. Many diagnostic and therapeutic procedures in medicine are carried out nowadays under X-ray fluoroscopic observation. In order to minimize the radiation exposure of the patient and the personnel, efforts are made to achieve an adequate image quality with the lowest possible radiation doses. With this in mind, manufacturers include in the X-ray equipment APR settings (APR=Anatomical Programmed Radiography), which contain pre-programmed values of the imaging parameters for various imaging scenarios (body regions/organs, clinical considerations, etc.). The values also include parameters of real-time dose control by means of which the dose is substantially controlled such that the mean brightness in a predefined field on the detector or image amplifier (e.g. a circle in the center of the detector) has a predefined value. The user normally has no possibility of better adjusting the APR settings for a particular situation. Such an adjustability would be desirable, however, since the predetermined imaging parameters in particular situations can be sub-optimal, for instance if the absorption model on which they are based is inappropriate under the latest clinical conditions. A typical example of such a situation is a catheter of large diameter used in electrophysiological examinations. A catheter of this type stands out clearly from its background, so that the X-ray images generated using standard parameters typically use a larger X-ray dose than necessary. In order to adjust imaging parameters of an X-ray apparatus, it is known from JP-11299765 to calculate imaging parameters for a given maximum X-ray dose such that the contrast-to-noise ratio of an interesting object is maximized. Against this background, it is an object of present invention to provide means for adjusting imaging parameters of an X-ray apparatus which permit minimizing of the radiation load. This object is achieved by a device with the aspects and features described and discussed via the present disclosure and a method with the aspects and features likewise described and discussed herein, with various advantageous embodiments proviede for illusstrative purposes. The device according to the invention serves to adjust imaging parameters of an X-ray apparatus and comprises the following components: A user interface, by means of which, with the aid of a preliminary image generated with the X-ray apparatus, a user may specify an image of interest region such as, for instance, an object (e.g. a vessel section and/or a catheter) and a visibility criterion desired for this image region. Preferably, the visibility criterion is calculated from the selected image region and its surroundings. The user interface typically comprises a monitor for displaying the preliminary images and input means and a keyboard and/or mouse. A data processing device linked to the user interface and the X-ray apparatus. The data processing device is arranged, for instance with suitable programs, to carry out the following steps: a) Calculation of adjusted imaging parameters of the X-ray apparatus, during the use of which a predetermined visibility criterion is achieved for the given image region. The given image region and the given visibility criterion for it may particularly be predefined by a user of the device based on a preliminary image, via the user interface. b) Control of the X-ray apparatus on the basis of the calculated, adjusted imaging parameters. The device described allows to set imaging parameters of an X-ray apparatus in relation to a concrete application situation, while a desired visibility criterion for an interesting image region such as, for instance, a catheter is taken as a reference. In this way, the user is provided with X-ray images that meet his requirements with regard to visibility of interesting structures, whereby the imaging parameters and therefore the radiation load are automatically set such that the desired result is achieved. By specifying a very low, but simultaneously sufficient, visibility criterion and by limitation to a relevant image region or object, the user may thereby achieve, in particular, that the images are generated with precisely the minimum required dose. This avoids both exposures with a high dose, which generate an unnecessarily high visibility of interesting structures, as well as exposures with too low a dose that would have to be repeated. The data processing apparatus may, in particular, be arranged for determining the current value of the visibility criterion for a given image region in a preliminary image. A step of this type may be carried out, in particular, within the framework of the calculation of adjusted imaging parameters, so that a current and a desired value of the visibility criterion are available for this. Depending upon the actual definitions chosen for the visibility criterion and the imaging parameters, conclusions concerning the adjusted imaging parameters may often be drawn from the ratio of the two variables. As imaging parameters of the X-ray apparatus to be adjusted, often those, in particular, come into consideration that influence the X-ray dose per exposure, the intensity of the X-ray radiation during an exposure and/or the quality of the X-ray radiation during an exposure. The X-ray dose is, in general, the fundamental variable on whose stipulation the values of intensity or radiation quality depend. Furthermore, the intensity of the X-ray radiation is typically determined by the tube current of the X-ray source, while the quality of the X-ray radiation is determined by the tube voltage and/or the setting values of filter elements of the X-ray source. For the definition of visibility criteria which relate to a particular image region or an object and/or the surroundings thereof, there are various possibilities. Preferably, the contrast-to-noise ratio CNR of the interesting image region may be used. This is defined as the quotient of the contrast of the image region to the noise in a predefined relevant region of the image. The “contrast of the image region” may be defined, for instance, as the difference between the (mean) gray value of the image region (or the mean gray value of the edge of the image region) and the (mean) gray value of a (nearer) surrounding area of the image region. Use of a mean gray value suggests itself since in X-ray images, the image background is not homogeneous and may vary greatly. Furthermore, the relevant region of the image in which the noise is determined, preferably extends to the image region and a surrounding area. This takes account of the fact that the image noise in an X-ray image is normally not constant, but varies locally. However, the image noise may possibly also be determined globally and taken as the basis for the whole image. The noise is typically quantified by its associated gray-value range in the relevant region. The stipulation of an interesting image region may be carried out by the user, in that, for instance, he completely delimits the region of interest with suitable input means or predefines corner points for predefined sectional geometries (rectangular window, etc.). Preferably, however, the data processing device is arranged to support the user in a semi-automatic process in that, by means of at least one pixel predefined via the user interface, it segments an interesting image region on a preliminary image. For instance, the user could stipulate the end points of a catheter section and the data processing device could automatically segment the piece of the catheter lying between these points. According to further feature of the device, the data processing device is arranged to take account of the influence of image manipulation procedures when calculating adjusted imaging parameters. A typical image manipulation procedure is noise filtration to reduce image noise. If therefore the contrast-to-noise ratio is taken as a basis for the visibility criterion, it is appropriate for the data processing device not to start from the noise values in the original image, but from the noise values after suitable noise filtration. The device also preferably contains a regulating module for feedback control of imaging parameters of the X-ray apparatus during an X-ray image. The adjusted imaging parameters calculated by the device may represent basic target values, such as the X-ray dose per image, where “dynamic” imaging parameters such as, for instance, the tube current or the tube voltage during an image are subject to constant feedback monitoring. Furthermore, the imaging parameters calculated by the device may also include starting values for feedback-controlled variables. In particular, the control module may contain an image brightness control in order to end the X-ray image when a predetermined threshold for image brightness is achieved. According to another further feature, the device contains means for detecting changes in the imaging geometry. Changes of this type may, for instance, come about through displacement of the patient table or rotation of the X-ray apparatus. With the imaging geometry, the effect of previously calculated imaging parameters also changes, so that the data processing device is preferably designed such that it adjusts these imaging parameters on detecting a change in the imaging geometry such that the predetermined visibility criterion is (probably) also achieved under the new imaging geometry. For an adjustment of this type, the data processing device may for instance determine the patient's thickness and take it into account. The invention also concerns a method for adjusting imaging parameters of an X-ray apparatus, including the following steps: a) Generating of a preliminary image with starting values for the imaging parameters; b) interactive stipulation of an interesting image region and of a visibility criterion desired for this image region; c) calculation of adjusted imaging parameters for the X-ray apparatus, with the use of which the predetermined visibility criterion for the predetermined image region is achieved; d) control of the X-ray apparatus based on the calculated, adjusted imaging parameters. The method implements, in a general form, the steps executable with a device of the type described above. For a detailed explanation of the details, advantages and further developments of the method, reference is therefore made to the above description. The invention also concerns an X-ray apparatus having an adjusting device for adjusting imaging parameters, the adjusting device including, for example, a user interface allowing a user to specify an image region of interst and a visibiliy criteria (e.g., a contrast-to-noise ratio of a region of interest) associated therewith, and a data processing device suitable to among other things, calculate adjusted imaging parameters,and control an X-ray apparatus on the basis of such calculated parmeters. Other benefical aspects and features specific to the adjusting device of the present disclosure are discussed hereinafter. These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter. On the left side of the FIGURE, an X-ray apparatus 1 comprising a C-arm with an X-ray source 2 and an X-ray detector 4 are shown. With the aid of the X-ray apparatus 1, 3 X-ray projection images of a patient may be generated, these being passed on to an image recording module 9 in an attached data processing device 5 (workstation). The data processing device 5 also contains a generator-control module 7, which is linked on its output side to the X-ray source 2 in order to control imaging parameters such as, in particular, the X-ray tube current I, the tube voltage V and the pulse length L of the X-ray pulses. The generator-control module 7 is also linked to the image recording module 9 in order, for instance, to carry out feedback image brightness control during an X-ray image. The data processing device 5 is also linked to a user interface 6 which contains a monitor 6a, a keyboard 6b and a mouse 6c. On the monitor 6a, an image generated with the X-ray apparatus 1 may be displayed. If the user desires a reduction of the X-ray dose and/or an improvement in the image quality, he may activate a suitable adjusting procedure on the data processing device 5. Within the framework of this procedure, firstly a current preliminary image generated with the X-ray apparatus 1 is displayed on the monitor 6a. For the generating of the preliminary image, for instance, a predetermined APR setting is used which was previously selected by the user according to the underlying clinical situation and is set, through a plurality of control parameters, to standard settings. The user is then required to indicate a certain region of interest ROI or an interesting object (an anatomical detail or a certain medical device, such as a catheter) on the image and to stipulate a desired value for a visibility criterion of this region ROI. By means of the interactive intervention by the user, definite identification of a region of interest ROI is, for instance, possible even if the interesting object itself has few characteristics or is ambiguous as, for instance, in the case of a plurality of medical instruments in the visual region with different requirements regarding image quality. The region of interest ROI may naturally also be incoherent or may include a plurality of individual objects, for instance an anatomical object such as the left ventricle and a catheter. Various possibilities are available for the indexing of an interesting object ROI by the user. For instance, the user may stipulate the start point A and the end point B of an interesting object ROI. The data processing device 5 may then extend the given points A, B to a more detailed object definition using suitable segmentation algorithms. Furthermore, as previously mentioned, a desired reference value must be stipulated by the user for a visibility criterion of the object. A suitable visibility criterion in this context is the contrast-to-noise ratio CNR, since it places the image noise in relation to the contrast between the object and its background. In particular, the (mean) contrast of the object relative to a surrounding area around the object may be placed in relation to the mean noise in a surrounding area around the object. The user may either stipulate a particular minimum reference value CNRref for the contrast-to-noise ratio, or a standard value from the system may be used for this, predefined, for instance, in the APR settings. Given the interesting image region ROI and the reference value CNRref, the data processing device 5 can then determine optimum imaging parameters for the given application, the precise patient and the interesting image region ROI. For this purpose, initially in a module 10 of the data processing device, for the current preliminary image, the contrast between the interesting object ROI and its surroundings is measured and the image noise determined. From these values, the current value CNRm of the contrast-to-noise ratio can be calculated. In a further module 8 of the data processing device 5, a comparison between the measured contrast-to-noise ratio CNRm and the desired value CNRref is subsequently carried out. If the measured value CNRm is smaller than the desired value CNRref, that is the visibility of the interesting object ROI is too small, the imaging parameters of the X-ray apparatus 1 must be altered such that in the subsequent image recordings, a high X-ray dose is used. If, however, the measured value CNRm is greater than the reference value CNRref, so that the region of interest ROI is imaged better than required, the X-ray dose can be reduced by a corresponding amount. Typically for carrying out the parameter adjustments described, the ratio between the measured and desired contrast-to-noise ratio, CNRm:CNRref is calculated. Taking account of technical and legally predefined limit values, the basic specifications for the X-ray images, such as the value Q0 of the desired dose per image may be made available, adjusted dependent upon the calculated ratio and the generator-control module 7. Furthermore, the module 8 may also give commands f to the collimator of the X-ray source 2 in order to control the setting of filter elements. During the creation of a subsequent X-ray image, dynamic imaging parameters, such as tube current I and tube voltage V are controlled with a brightness-based dose check, whereby the adjusted imaging parameters Q0 are taken into account, in order to depict the interesting object ROI with an optimum X-ray dose. The X-ray dose Q may generally be influenced by two parameters: the radiation intensity, which is determined by the tube current I; and the radiation quality, which is determined by the extent of the ray filtration and by the tube voltage. According to a special embodiment of the method, only the radiation intensity is adjusted, dependent upon the clinical conditions. This means that the number of X-ray photons irradiating the patient is increased linearly in relation to the ratio between the desired and the measured contrast-to-noise ratios CNRref:CNRm. In another embodiment of the method, it is not only the tube current I, but also the radiation quality that is modulated in order to achieve the desired contrast-to-noise ratio between the interesting object ROI and its surroundings. In the process, various compromises have to be found between different, partially contradictory requirements, in order to find the optimum imaging conditions, e.g.: patient thickness vs. image quality (CNR) vs. kVp (peak tube voltage), patient thickness vs. patient irradiation vs. kVp. In order to improve the results obtained with the method, in the calculation of the new dose settings Q0, in module 8 the noise filtration during processing of X-ray images may be taken into account. As the dose is reduced, the noise component of an image signal increases. However, by means of image processing methods, the noise may be partially eliminated and the image quality thereby improved. For this reason, it is advantageous for the exposure parameters to be determined taking account of noise filtration. The method may be further developed such that the calculated imaging parameters, such as the dose setting Q0, may be adjusted to changes in the acceptance angle and the system geometry. Thus, during the X-ray exposures, the physician may, for instance, displace the patient table or change the position of the C-arm of the X-ray apparatus 1 in order to depict a different perspective of the patient's anatomy. For the handling of such procedures, the patient thickness may be determined from the preliminary image, used to determine the measured contrast-to-noise ratio CNRm. Following changes to the system geometry, the patient thickness and the quotient between the actual contrast-to-noise ratio CNRm and the desired value CNRref must then be recalculated to update the dose settings Q0 based on these calculations and to pass them on to the generator-control module 7. In this way, despite an altered geometry, the system can continue to operate at an optimum balance between image quality and radiation dose used. Summarizing, the above method achieves the following advantages: minimizing radiation load while simultaneously ensuring adequate visibility of interesting structures; in that regard, dose reductions by a factor of 2 are possible; improvement of visibility of details given inadequate imaging conditions; no necessity for segmentation of an interesting object in real time (i.e. no potential source of instability); obviousness of the interesting object even in the presence of a plurality of objects in the visual range; ensuring a given level of visibility even when the interesting object is situated outside the viewing region; robustness with respect to changing the system geometry, since the fundamental visibility model of the object of interest can be extrapolated in relation to various patient thicknesses; small changes required to the existing system architectures for integration of the method; in particular the existing brightness-based dosing may remain unchanged; the number of APR settings to be implemented may be minimized.
	summary
047643404	abstract	A device for relieving thermally induced stresses developed in a nuclear fuel assembly during reactor heatup is disclosed herein. The device generally comprises a stress relieving fastener capable of connecting a fuel assembly top nozzle, which may be stainless steel, to a threaded stud, which may be Zircaloy. The stud is attached to a fuel assembly channel. The fastener includes a threaded nut having a deformable portion for relieving thermally induced stresses developed in the stud by the differential thermal expansion of the top nozzle and stud. In a first embodiment of the nut, the deformable portion comprises a circumferential, deformable ridge which is substantially recessed from the marginal edge of the nut and which is disposed on the bottom most surface of the nut. The ridge contacts the top nozzle when the nut threadedly engages the stud. A second embodiment of the nut is similar to the first embodiment except that the deformable ridge is disposed flush with the marginal edge of the nut. The deformable portion in the second embodiment may also include a circumferential, deformable first groove which is formed in the lower portion of the nut. In addition, the second embodiment may include a deformable second groove formed in the bottom most surface of the nut. During reactor heatup, thermally induced stresses may develop in the stud. The deformable portion of the nut deforms, thereby relieving the thermally induced stresses.
	abstract	Molecule for attaching a radioactive parent nuclide to a support, comprising at least one functional group for attaching the radioactive parent nuclide; and a molecular moiety suitable for establishing a nonpolar bond to the support.
047584033	description	DESCRIPTION OF PREFERRED EMBODIMENTS FIGS. 1 and 2 show schematically a fragment of a grid which comprises two intersecting sets of plates 10 and 12 defining pockets or openings for receiving elongate elements 14. The major part at least of these elements are fuel elements 30 as shown in FIG. 6. Others may be guide tubes 32 which slidably receive reactivity control and/or shim rods. A plurality of such grids 22 will be distributed along the elongate elements and secured to the guide tubes 32. The guide tubes 32 and end nozzles 34,36 secured thereto constitute a supporting structure of a fuel assembly 40. Each grid pocket is provided with two half-fins, placed on the same side of the grid. Because each of these half-fins only concerns a single pocket, it is possible to place all the half-fins on the same side of the grid since they do not interfere with the assembly of the half-plates by lap joint intersection. The half-fins 18 oriented in one direction may be carried by plates 12, those 20 oriented in the perpendicular direction being carried by plates 10. Thus, each pocket comprises two opposite half-fins along one of its diagonals and at each intersection of two orthogonal plates are to be found two half-fins perpendicular to each other. In FIG. 1 it can be seen that the amount of material represented by the half-fins is the same for all the pockets. This amount of material is also the same for all the hydraulic cells, such as cell 16 shown by broken lines in FIG. 2. The hydraulic balance is achieved in all the cells, except possibly for the edge cells, and comprises two incoming flows and two outgoing flows as can be seen in FIG. 2. Finally, there is direct circulation in the constrictions in two directions. The half-fins may be formed by simply bending flaps stamped in the plates before assembling these latter. In the variant shown in FIG. 3, each cell such as 16a only comprises a single half-fin 18a or 20a. The half-fins of two adjacent cells are orthogonal and the diagonal symmetry of the hydraulic flows is maintained. The hydraulic balance is maintained, with one incoming flow and one outgoing flow. The amount of material represented by the fins remains the same for all the hydraulic cells. FIGS. 4 and 5 show a possible grid construction corresponding to the diagram of FIG. 3. Grid 22 shown in these Figures has a general conventional construction. It comprises plates 10 and 12, generally made from a zirconium based alloy, assembled by lap jointing and welded at their intersection points. Each plate comprises fuel element bearing bosses 24 and different openings cooperating with springs for applying the elements against the bosses. In the case illustrated, these springs are inserted. Some of the springs, for example spring 26, are double and are inserted in straddling relation in indentations opening in one of the edges of the plates. Other springs, such as spring 28, are single and so of dissymmetrical construction. Grids of this kind are described in prior documents, particularly French Patent No. 82 17717. The grid of FIGS. 4 and 5 comprises a half-fin per hydraulic cell. Each plate 10 carries half-fins 18a with a pitch double that of the pockets. All the half-fins of the same plate 10 are slanting in the same direction, opposite that of the half-fins of the two adjacent plates 10. The half-fins 18a are thus disposed in quincunx arrangement. One pocket out of two is thus provided with two half-fins 18a placed at the ends of its diagonal, at least the current part of the grid, and the pockets respectively provided with and devoid of fins are distributed in a checkerboard arrangement. This arrangement must sometimes be modified at the edge of the grids where certain half-fins 18a may have a reversed arrangement, symmetrical with respect to the external plate. The same arrangement is to be found for the half-fins 20a carried by plates 12. The choice between the arrangement shown in FIG. 1 and that of FIGS. 3 to 5 will depend on the relative importance which is attached to homogenization of the mixture and reduction of pressure losses. In the case of a single half-fin per hydraulic cell, mixing of the fluid streams by deflection is not as complete, but on the other hand the pressure drop is appreciably reduced since the number of half-fins is reduced practically by half. The invention is susceptible of numerous variants and it applies to grids of very varied construction. In particular, the invention may be used when the springs for holding the fuel elements in the grids are formed by parts stamped out from the plates, as is described for example in French Patent No. 1,536,258.
	summary
	abstract	A containment tube includes a sealed tube comprising silicon carbide, first and second ends, an inner bore extending along at least a portion of its axial length between the first and second ends, and contains a radioactive material within the bore of the sealed tube. The first end has a plug residing in the inner bore to close the first end, and the second end has a distal wall that closes the inner bore at the second. At least one of the first or second ends is bonded to the sealed tube by a sinter bond.
	abstract	The present invention provides a boiling water reactor nuclear power plant in which a reactor core support plate, upper grid plate, and a reactor core consisting of fuel assemblies supported by these plates are provided in the inner base portion of a nuclear reactor pressure vessel. Control rod guide tubes and a reactor core shroud are positioned over the upper grid plate, and a control rod drive mechanism is provided further above same, whereby the control rods can be inserted from above the reactor core, and natural circulation of cooling water inside the reactor can be achieved by means of a chimney effect of the control rod guide tubes. According to the above structure, there can be provided a compact and economical nuclear power plant.
050842340	summary	BACKGROUND OF THE INVENTION The invention is directed to an absorption casing for a source of radioactive radiation, particularly for a nuclear reactor, having a first layer for the absorption of gamma radiation, a second layer for the absorption of neutron radiation and a third layer for the absorption of alpha and beta radiation. In nuclear reactors, a plurality of safety precautions are provided for preventing escape of direct radioactive radiation and radioactive fission products. For instance, the pressure vessel of the reactor in a nuclear power plant, being a steel containment, reduces the gamma radiation. The pressure vessel of the reactor is surrounded by a shield of steel-reinforced concrete, having a thickness of about two meters, which effects additional screening against the remaining gamma radiation and neutron radiation. The concrete safety container, having a sealing skin, and the reactor building present further barriers against the escape of radioactive radiation. Thus, for shielding the reactor, a plurality of comparatively thick walls are required. In their totality, all these barriers provide that, outside of the reactor, escape of direct radiation is possible only to an allowable extent. If one of these barriers fails due to leakage, there is no secure protection anymore against the issuing of radioactive radiation. Reliable protection against the gaseous radioactive fission products generated during nuclear reaction does not exist. SUMMARY OF THE INVENTION It is the object of the invention to provide an absorption casing for a source of radioactive radiation which effects reliable protection against intrusion or escape of radioactive fission products. According to the invention, the object is solved in that a fourth layer of gas-impermeable material is provided, enclosing the source of radioactive radiation from all sides, for retaining the gaseous fission products. According to the invention, the source of radioactive radiation is completely surrounded by a layer of gas-impermeable material. This fourth layer effects complete enclosure of the radioactive radiation source. Therefore, the radioactive fission products cannot escape and remain within the space enclosed by the fourth layer. Accordingly, the radioactive fission products cannot intrude into the remaining layers for absorption of the different types of radiation and contaminate these layers. By shielding the radioactive radiation source with respect to the radioactive fission products, these gaseous substances, being generated in a nuclear reaction, can be evacuated on a controlled basis without contaminating other protecting barriers. Preferably, the fourth layer consists of a zirconium alloy. The layer of zirconium alloy, even if having a small thickness only, reliably shields the environment of the radioactive radiation source against gaseous fission products. In principle, the succession of the individual layers is optional; however, the fourth layer of gas-impermeable material should be closest to the source of radiation so as to protect the subsequent layers against penetration by radioactive fission products. The first layer for absorbing gamma radiation preferably consists of lead, the second layer for absorbing neutron radiation consists of boron, hafnium, cadmium or beryllium, and the third layer for absorbing alpha and beta radiation consists of aluminium. For effectively absorbing the radioactive radiation and for shielding off the gaseous radioactive fission products, respectively, the absorption casing need only have a comparatively small thickness because the individual layers, even when of comparatively small thickness, already accomplish effective absorption of radiation and shielding against the radioactive substances. By the series of layers of the invention, the radioactive rays (alpha, beta, gamma and neutron radiation) are effectively absorbed. The thickness of the individual layers substantially depends on the intensity of the radiation. The lead layer should be about three times as thick as each other layer. By the inventive casing for the absorption of radiation and fission products, the environment of plants having nuclear reactors is reliably protected. Therefore, the invention decisively contributes to the protection of the environment against radioactive contamination. For protection against risks in nuclear power plants having light-water reactors, the above-mentioned four layers are sufficient. In "fast breeders" or "fast breeding reactors", in which plutonium is generated during nuclear fission, it is suitable to provide a fifth layer consisting of titanium. By this titanium layer, the radioactive radiation issuing from the plutonium is absorbed in a particularly effective manner. Preferably, all of the layers are arranged at distances to each other to allow different expansion of the individual layers upon rise of temperature. Spacers can be arranged between the individual layers; preferably, between each pair of neigboring layers, there is arranged a layer of an elastic material to compensate the difference in expansion of neigboring layers. The absorption casing of the invention can be used for linings in nuclear power plants, transport containers for radioactive materials, intermediate and final waste disposal sites for radioactive waste, as well as for nuclear fuel processing and reprocessing plants. Further, the absorption casing can be used for enclosures of atomic satellite drive units and for linings of X-ray rooms and laboratories. Additionally, the absorption casing of the invention can find application in the protection of fall-out shelter rooms, production sites and military buildings against radioactive radiation and substances. For shielding the reactor of a nuclear power plant, an absorption casing according to the invention is preferably provided both on the inner side of the reactor building and on the inner side of the reactor safety container which is arranged within the reactor building. In both cases, the layer of zirconium alloy forms the layer closest to the reactor core. A further possibility for shielding the reactor consists in that the series of layers is integrated into the wall of the reactor building and the reactor safety container, the fourth layer (of zirconium alloy) being the innermost layer also in this case. By arranging the successive layers both at the reactor building and at the safety container or, respectively, on the walls of the reactor building and of the safety container, a double protection is given with respect to the reactor. Even in case of a maximum credible accident, involving the melting of the reactor core and--in the further course of the accident--of the concrete shell of the safety container, the absorption casing on the reactor building or in the wall thereof offers reliable protection against radioactive radiation and radioactive substances until destruction of the safety container as such. Also for anti-radiation shielding of shut-down nuclear power plants, the absorption casing of the invention is applicable. In this case, the absorption casing is preferably arranged around the entire reactor building. This can particularly be achieved in that the series of layers is attached to the reactor building from the outside, with the layer of zirconium alloy being arranged on the inner side of the absorption casing facing the reactor building. For anti-radiation shielding of final radioactive-waste disposal sites, the absorption casing is preferably arranged around the entire final disposal site. Also here, the layer of zirconium alloy is located on the inner side of the absorption casing. According to the respective intensity of the radioactive radiation to be shielded off, it can also suffice to close only the entrances to the final radioactive-waste disposal site by the absorption casing. Finally, the absorption casing of the invention is also suited for the protection of all kinds of installations against radioactive radiation and substances; in these cases, the layer of zirconium alloy is arranged on the outside of the absorption casing surrounding the installation to be protected. The absorption casing of the invention is adapted to provide anti-radiation shielding of shut-down nuclear power plants by "secured containment" of the nuclear power plant. In this variant of an anti-radiation shielding, all solid and insoluble active substances are permanently contained in situ by a tight safety enclosure. The monitoring of technical safety systems and safe access to the shut-down plant are guaranteed over the whole time span of the containment. Access to the premises is possible then as before, and safety checks, performed by measuring devices, and the like procedures are possible at all times. The radiation exposure resulting from the "securely contained" shut-down nuclear power plant is considerably decreased by the inventive absorption casing. As compared to other nuclear waste disposal measures, complete containment of the shut-down nuclear power plant by a safety enclosure provided with the absorption casing can be obtained at relatively low costs. An embodiment of the invention will be explained in greater detail hereunder with reference to the Figures, wherein
	summary
052084620	abstract	A phosphor is placed on a light emitting surface of a solid state optical source. The phosphor absorbs the narrow bandwidth light from the optical source, and emits light that has a wide bandwidth. A lens is used to collect and focus the wide bandwidth light.
	description	The present application claims priority from Japanese application JP 2006-322204 filed on Nov. 29, 2006, the content of which is hereby incorporated by reference into this application. The present invention relates to a method for manufacturing a wafer having a circuit pattern, and more particularly to a technique of inspecting a fine pattern using a charged particle beam. The scanning electron microscope is an apparatus for accelerating the primary electron discharged from the electron source, converging the same by an objective lens to narrow down the primary electron beam, scanning the sample with the primary electron beams by using a scanning deflector, detecting secondary signals generated from the sample by the irradiation of the primary electron beam and displaying this detected signal intensity as observation image. In order to obtain highly contrasted observation images, an efficient detection of secondary signals is required. In order to make a detector arranged outside the optical axis detect efficiently secondary signals, it is necessary to apply an electromagnetic field on the optical axis to deflect the secondary signals. However, this electromagnetic field increases the aberration of the primary electron beam. Therefore, in order to obtain a high-definition observation image enlarged at a high magnification, it is necessary to reduce the aberration of the primary electron beam. Therefore, it is necessary to contain the aberration of the primary electron beam generated on the optical axis between the electron source and the focus point on the sample. JP-A No. 7(1995)-192679 discloses the technology of separating the orbit of the secondary electrons and the reflected electrons by using a deflector for deflecting the secondary electrons out of the axis of the primary electron beam and detecting selectively the secondary electrons and the reflected electrons. JP-A No. 9(1997)-171791 shows an example of reducing the aberration amount of the primary electron beam generated in the secondary electron deflection field to detect efficiently the secondary electrons. JP-A No. 9(1997)-171791 discloses the technology of providing a secondary electron conversing electrode in which an opening for allowing the passage of the primary electron beam above the secondary electron detector, converting the secondary electrons generated or the reflected electrons from the sample that had collided with the secondary electron conversing electrode into secondary electrons, deflecting and detecting the same by the detector by using the secondary electron deflector to which the electromagnetic field is applied orthogonally to the secondary electron suction electric field, and canceling deflection by the electric field and deflection by the magnetic field by orthogonalizing the suction electric field and the magnetic field and correct the same. This technology is a method of detecting indirectly the secondary electrons (indirect detection method of secondary electron), and the deflection amount of the secondary electron can be small, and the impacts on the primary electron beam will be small in comparison with the direct detection method of deflecting the secondary electron substantially towards the detector. However, in the configuration of the detector disclosed in JP-A No. 9(1997)-171791, the energy width of the primary electron beam generates deflection chromatic aberration in the secondary electron deflection field, and expands the diameter of the primary electron beam by several nanometers. For a scanning electron microscope in which a nm-order resolving power is required, the deflection chromatic aberration described above is not negligible. On the other hand, a technology for reducing the deflection chromatic aberration by the secondary beam deflector is disclosed in JP-A No. 2001-357808. JP-A No. 2001-357808 discloses the technology of canceling the deflection aberration of the primary electron beam generated in the deflector by installing a secondary electron deflector that applies magnetic field orthogonally to the secondary electron deflection magnetic field in order to deflect the secondary electrons, and by installing another deflector to be operated under the condition that the polarity of deflection direction will be directly opposite to the electron source side from the deflector mentioned above. A semiconductor circuit pattern inspection includes a step of detecting defects at a low magnification and another step of obtaining inspection images for observing detailed defects at a high magnification and inspecting patterns. The normally used magnification is approximately 5,000-40,000 times for the detection of defects described above, the magnification of the image for inspection mentioned above is approximately 50,000-200,000 times and the resolution performance required for the images to be inspected is in the nm order. Secondary electron images obtained mainly by detecting the secondary electrons generated in the surface layer of sample are contrasted by the difference in materials and edge effect. As a result, it is possible to detect defective parts by comparing the secondary electron images of two observation points having the same structure. However, the surface of a semiconductor wafer is often covered with an insulator to form a circuit, dapples of brightness in the image (shadings) not attributable to defects often develop on the secondary electron image due to an electrostatic charge of the sample, after the irradiation of primary electron beam. Such shadings are highly likely to cause wrong detections in the process of detecting defects in the secondary electron images. Therefore, in order to correctly detect and observe defects in the secondary electron images, it is necessary to obtain high-definition and highly contrasted observation images without shading. JP-A No. 9(1997)-171791 does not pay attention to the fact that, due to changes in the angle of the deflection electric field to the secondary electron conversing electrode on the equipotential surface depending on the in-plane position on the secondary electron conversing electrode where secondary electrons collide, the efficiency of detecting the secondary electrons discharged from the secondary electron conversing electrode (called “tertiary electron”) is varied. There is no problem if secondary electrons collide in a narrow area on the secondary electron conversing electrode. However, when the secondary electrons are greatly deflected due to a low magnification for observation or uneven distribution of electrostatic charge of sample, secondary electrons collide in the area where detection efficiency of the secondary electron conversing electrode change resulting in the shading described above. These points are not taken into consideration. In electron beam application apparatus, the primary electrons extracted from the electron source have an energy width determined by the electron source. When primary electrons pass through the secondary electron deflector shown in JP-A No. 9(1997)-171791, they go straight ahead because the latter is designed in such way that the deflection action due to the electric field and the deflection action due to the magnetic field applied vertically to the electric field for the primary electron beam having an energy V would cancel each other. However, if the primary electrons have an energy width of ΔV, the deflector mentioned above gives an angle of deflection θ to the primary electron beam having an energy of V+ΔV with the optical axis. And it gives a deflection distance r at a place separated by a distance L from the deflector. Such deflection amounts enlarge the diameter of the primary electron beam on the sample, and causes resolving power to deteriorate, and as a result it will be difficult to achieve the required resolving power at a high magnification. The technology of reducing the impact of aberration by this deflector on primary electron beam is disclosed in JP-A No. 2001-367808 as described above. However, it is limited to the disclosure of constitution according to the direct detection method of secondary electrons, and its application to the indirect detection method of secondary electrons is not disclosed. And according to JP-A No. 2001-357808, the first deflector for deflecting the secondary electrons towards the detector and the second deflector for canceling deflection chromatic aberration are located at separate positions. As a result, the second deflector corrects the deflection angle θ that the first deflector gives to the primary electrons, and cannot correct the deflection distance r. The object of the present invention is to provide a charged particle beam apparatus, a scanning microscope, and sample observation method wherein the deflection aberration of the primary electron can be corrected in the indirect detection method of the secondary electrons. In order to achieve the above-mentioned object, the present invention provides a charged particle beam apparatus for irradiating a sample with primary charged particle beam and detecting secondary charged particles secondarily generated including a stage to hold the sample, a charged particle source for generating the primary charged particle beam, a condenser lens for converging the primary charged particle beam, an objective lens for irradiating the sample with the converged primary charged particle beam, a secondary electron conversion unit arranged between the condenser lens and the objective lens, and the secondary electron conversion unit includes a secondary electron conversing electrode to which the secondary charged particles generated from the samples are collided, a first E×B deflector for deflecting the secondary electrons generated on the secondary electron conversing electrode, a secondary E×B deflector for reducing the deflection chromatic aberration generated on the primary charged particle beam by the first E×B deflector, and a detector for detecting the secondary electrons generated by the secondary electron conversing electrode. And in the sample observation method according to the present invention, a desired area of the sample is scanned with the primary charged particle beam, the secondary charged particle generated secondarily from the desired area as a result of the irradiation of the primary charged particle beam is made to collide with the secondary electron conversing electrode, and then the secondary electrons generated by the collision with the first E×B deflector arranged on the surface of the secondary electron conversing electrode on the sample side through an insulator are injected into the detector. At the same time, the deflection chromatic aberration that develops in the primary charged particle beam in the first E×B deflector by the second E×B deflector arranged on surface of the secondary electron conversing electrode on the electron source side through an insulator is reduced. And according to this sample observation method, it is possible to reduce deflection color aberration by disposing the first E×B deflector and the second E×B deflector with a 180 degree rotation to the primary electron particle beam. Furthermore, according to this sample observation method, it is possible to reduce the in-plane variation of detection efficiency by applying the voltage of the ground electrode of the first E×B deflector to the secondary electron conversing electrode as the reference potential. According to the present invention, it will be possible to detect efficiently secondary signals without increasing aberration of the primary electron beam, and to increase the inspection speed and sensitivity by detecting defects by means of high-resolution and highly contrasted observation images. We will describe below the embodiments of the present invention with reference to drawings. FIG. 1 shows a review SEM (scanning electron microscope) constituting the first embodiment. The review SEM of this embodiment is an apparatus designed to obtain the image of defects or foreign matters in a semiconductor wafer, to detect fatal defects and classify the detected defects. The review SEM is an electron beam applied apparatus carried out by a scanning electron microscope having a semi-in-lens objective lens, and includes roughly speaking an electron optical system, a sample chamber 27, a control unit 26 and an electronic detection system. The electronic optical system includes an electronic gun 1, an extraction electrode 2, an acceleration electrode 3, a first condenser lens 4, a second condenser lens 6, an aperture diaphragm 5, a scanning deflector 7, an objective lens 8, and a magnetic electrode 13 above the objective lens. The sample chamber 27 includes a stage 9. The magnetic electrode 13 above the objective lens includes a booster voltage power source of variable voltage 12, and the stage 9 includes a retarding voltage power source 11 with variable voltage. The electronic detection system includes E×B deflectors 31 and 32, secondary electron conversing electrodes 33 and 35, a secondary electronic detector 34, stereoimage detectors 41a and 41b. The secondary electron conversing electrode 33 is connected with a voltage power source 37. The detected signals are sent to the detected signals processor 24, where the former are computed and processed for the judgment of defects. The images taken in are displayed on the monitor 25. The operational commands and operational conditions of various parts of the apparatus are inputted and outputted by the control unit 26. As shown in FIG. 2, the E×B deflector 31 includes four electrodes for making the deflection magnetic field 60, 61, 62a and 62b, four coils for making a deflection magnetic field 63a, 63b, 63c, and 63d, a ground electrode 67, and insulators 66a and 66b. The electrode 60 is connected with the voltage power source 64 so that the positive voltage may be applied, and the electrode 61 is connected with the voltage power source 65 so that the negative voltage may be applied. The electrode 61 may be grounded in some cases. The electrodes 62a and 62b are grounded. The E×B deflector 32 includes four electrodes for making the deflection magnetic field 70, 71, 72a and 72b, four coils for making the deflected magnetic field 73a, 73b, 73c, and 73d, a ground electrode 77, and insulators 76a and 76b. The electrode 70 is connected with the voltage power source 74 so that the positive voltage may be applied, and the electrode 71 is connected with the voltage power source 75 so that the negative voltage may be applied. The electrode 71 may be grounded in some cases. The electrodes 72a and 72b are grounded. The secondary electron conversing electrode 33 is connected with the voltage power source 37. It is connected with the E×B deflector 31 through the insulator 66a and with the E×B deflector 32 through the insulator 76a. The two E×B deflectors 31 and 32 are connected on the same axis with the opening through which the primary electron beam passes serving as the central axis. The secondary electron detector 34 includes a fluorescent body 38, a secondary electron suction high-voltage electrode 39 and a detector 40. In this embodiment, E×B deflectors 31 and 32, a secondary electron conversing electrode 33, and a secondary electron detector 34 located between the condenser lens and the scanning deflector 7 constitute the secondary electron conversion unit. This secondary electron conversion unit has a function of reducing the deflection chromatic aberration. This secondary electron conversion unit should preferably be disposed near the crossover point of the primary electron beam passing through the condenser lens. As the electron source for the electron gun 1, for example a diffusion supply-type thermal field emission electron source is used. And the electron gun 1 has an extraction electrode 2, and the primary electron beam is extracted from the electron gun 1 by applying voltage on the extraction electrode 2. A negative voltage −V0 is applied on the acceleration electrode 3, and the primary electron beam passes through the acceleration electrode 3 with an energy of V0. Then, it is converged by the condenser lens 4 and constitutes a crossover 14. The condenser lens 4 is connected with the condenser lens power source 20, and the control unit 26 controls its operation. And at the time of passing through the aperture 5, its current is limited. And the primary electron beam is converged by the condenser lens 6 to make the crossover 15. The condenser lens 6 is connected with the condenser lens power source 21, and the control unit 26 controls its operation. The condenser lens 4 and the condenser lens 6 are controlled in such a way that the crossover 15 may be located between the E×B deflector 31 and the scanning deflector 7. The primary electron beam is narrowed down sharply by the objective lens having an objective lens power source 23 controlled by the control unit 26. The stage 9 includes a voltage-variable retarding voltage power source 11 so that the high-voltage potential-Vr for decelerating the primary electron beam (retarding potential) may be variable. Due to the retarding potential, the primary electron beam, being drastically decelerated directly above the substrate to be inspected 10 mounted on the stage 9, is converged on the substrate to be inspected by the objective lens 8. And the scanning deflectors 7 disposed in two stages between the condenser lens 6 and the objective lens scan the substrate to be inspected 10. The scanning deflectors 7 are connected with the scanning signal generator 22, and the control unit 26 controls their operation. The energy of the primary electron beam at the time of irradiation on the sample is (V0−Vr). Since the values of V0=2 kV and Vr=1.2 kV are set in this embodiment, the sample is irradiated with a primary electron beam of 800 eV. At this time, we take the running direction of the primary electron as the z axis. The irradiation of the primary electron beam generates secondary electrons having an energy of approximately 0-50 eV, and reflected electrons having an energy higher than 50 eV from the substrate to be inspected 10. The energy of the generated secondary electrons is expressed as ESE. The angle θS.E. between the sample surface and the normal line shall be the emission angle of the secondary electrons and the reflected electrons. Since the retarding voltage Vr is applied on the stage, the energy of the secondary electrons will be (ES.E.+Vr). The electrode 13 above the objective lens includes a variable-voltage booster voltage power source 12 so that a positive potential (booster potential) for increasing secondary electrons may be applied thereon. In this embodiment, we have chosen a booster potential of 2 kV. This potential pulls up the secondary electrons to the electron source side by the booster potential, causes the secondary electrons to advance being wound up towards the electron source side by the magnetic field created by the objective lens, and to pass through the hole in the secondary electron conversing electrode 35 to collide with the secondary electron conversing electrode 33. The reflected electrons generated by the substrate to be inspected are divided into four categories by the angle of emission. (1) The component having a very low emission angle θS.E. passes through the hole of the secondary electron conversing electrode 35 and collides with the secondary electron conversing electrode 33. (4) The component having a high emission angle θS.E. collides with the objective lens 8 and fails to reach the detector. And the component (2) close to (1) collides with the secondary electron conversing electrode 35 between (1) and (2), and the component (3) close to (4) directly penetrates into the detectors 41a and 41b. The collision of the reflected electrons with the secondary electron conversing electrode 35 results in the generation of secondary electrons from the secondary electron conversing electrode 35. The detectors 41a and 41b detect the signals of secondary electrons. The reflected electrons generated at large angles fail to collide with the secondary electron conversing electrode 35 and are directly detected by the detectors 41a and 41b. The detectors 41a and 41b are located at corresponding positions (right and left). This structure is intended to separate the reflected electron into the right and left ones and to enable to observe more three-dimensionally the defects, foreign matters and other items for observation on the substrate to be inspected. The secondary electron conversing electrode 33 is a discoidal electrode having a central hole for allowing the passage of primary electron beam and includes a means for applying voltage. Phosphor bronze is used as its material because of ease of acquisition and processing, but other materials may be used. Its surface is coated with gold mainly in order to prevent the adhesion of polluting matters by the irradiation with secondary electron beams. In addition to gold, silver, platinum and the like may be used. And materials having a high efficiency of generating secondary electrons by the irradiation of electron beams such as MgO may sometime be coated on the gold coating layer. The wound up secondary electrons are deflected by the scanning deflector 7 and collide with the secondary electron conversing electrode 33. Secondary electrodes are generated on the secondary electron conversing electrode 33, and the secondary electrons are deflected by the secondary electron deflector 31 in the direction of the secondary electron detector 34. As mentioned above, FIG. 2 shows an embodiment of the deflectors 31 and 32. In FIG. 2, the E×B deflector 31 for deflecting the secondary electron is situated on the side of the stage from the secondary electron conversing electrode 33 and is connected with the secondary electron conversing electrode 33 through an insulator 76a. The E×B deflector 22 for canceling the deflection aberration created by the deflector 31 in relation to the primary electron beam is situated on the side of the electron source from the secondary electron conversing electrode 33, and joins with the secondary electron conversing electrode 33 through an insulator 76a. Although the E×B deflector 31 and the E×B deflector 32 have the same electrode and coil disposed in the same way, they are disposed in two-rotation symmetrical positions so that their deflection electric field and their deflection magnetic field may be inversed. A cross-sectional view cut out along the line (1) in FIG. 2 is the central section of FIG. 2, and illustrates the detector 34 and the E×B detector 31. The E×B deflector 31 is a deflector that puts the deflection electric field (E) and the deflection magnetic field (B) into action orthogonally. It creates a deflected electric field (E) by creating a difference in electric potential between two symmetrical electrodes, i.e. the electrode 60 and the electrode 61 so that the secondary electrons may be deflected towards the detector 34. In this embodiment, the electrode 60 is charged with the positive potential and the electrode 61 is charged with the negative potential. The deflection direction of the secondary electron is expressed by x axis. When an axis perpendicular to the x axis and the z axis is expressed as the y axis, the disposition of symmetrical grounding electrodes 62a and 62b on both sides of the y axis can create a uniform deflection electric field in the deflector 31. The electrodes 60, 61, 62a and 62b are sections of a discoidal electrode obtained by splitting the same. And the degree of splitting is 120 degrees for the electrode 60 and the electrode 61, and 60 degrees for the electrode 62a and the electrode 62b. And the electrode 60 is a mesh electrode allowing the secondary electrons to penetrate inside and to reach the detector 34. The detector 34 includes a second electron extraction high-voltage electrode 39 for accelerating secondary electrons, a fluorescent body 38 and a detector 40. The electrode 39 accelerates the secondary electrons that have penetrated the mesh electrode and the secondary electrons emitted from the mesh electrode with which the secondary electrons had collided. In this embodiment, we applied a 10 kV voltage to the electrode 39, accelerated the secondary electrons to penetrate into the fluorescent body 38 and detected the secondary electrons that emitted from the same with the detector 40. For the detector 40, we used an electronic light amplifier. For the detector 40, a semiconductor detector, a multi-channel plate detector or the like may be used. The electrode 61, the electrode 62a, and the electrode 62b need not be mesh electrodes but may be plate electrodes. The deflection magnetic field (B) is made of two pairs of electrode 60, electrode 61 and electrode 62a and electrode 62b arranged outside the part where they are adjacent, a total of four coils 63a, 63b, 63c, and 63d. The cross-sectional view obtained by cutting off FIG. 2 upper section by the line (2) is FIG. 2 lower section and illustrates the E×B detector 32. The electrode 70 is charged with a negative potential, while the electrode 71 is charged with a positive potential. Therefore, its deflection polarity is reverse of that of the deflector 31. Its deflection magnetic field is put into action in such a way that it may be reverse to that of the deflector 31. The E×B deflectors 31 and 32 are operated under a condition that they have no deflective action on the primary electron beam (Wien condition) when the deflection direction of the electric field and the deflection direction of the magnetic field vis-à-vis the primary electron beam cancel each other. Let us consider the following model of deflector. When the length of a deflection electrode is expressed by 2×1L, the distance between deflection electrodes is expressed by dL, when +VL/2 is applied to the deflection electrode in the deflection direction of the secondary electron, and −VL/2 is applied to the opposite deflection electrode, and when the intensity of the deflection magnetic field is expressed by BL, the deflection amount ΔxL at a place separated by LL from the center of the center of the deflector to the sample side is expressed by the equation (1). [Equation 1] Δ ⁢ ⁢ x L = ( deflection ⁢ ⁢ amount ⁢ ⁢ in ⁢ ⁢ the ⁢ ⁢ deflection ⁢ ⁢ electric ⁢ ⁢ field ⁢ ⁢ Δ ⁢ ⁢ x EL ) - ( deflection ⁢ ⁢ amount ⁢ ⁢ in ⁢ ⁢ the ⁢ ⁢ deflection ⁢ ⁢ magnetic ⁢ ⁢ field ⁢ ⁢ Δ ⁢ ⁢ x BL ) = l L × L L d L × V L V 0 - 2 ⁢ e m × B L × l L × L L V 0 Equation ⁢ ⁢ ( 1 ) In the above equation, the acceleration voltage is expressed by V0, the mass of electron is expressed by m, and the quantity of electric charge of electrons is expressed by e. It is possible to satisfy the Wien condition by setting the parameters in such a way that ΔxL may be nil. Since the force that the deflection electric field exerts to the secondary electrons and the force that the deflection magnetic field exerts to the same are in the same direction, in the equation (1) the symbol of ΔxL will be positive, and the deflection action works towards the detector side. And although in this embodiment we showed two pairs and total four deflection magnetic coils, it is possible to an orthogonal magnetic field with a pair and two coils. However, with two pairs and total of four coils, it is possible to create a magnetic field of a higher orthogonal degree to the deflection electric field. FIG. 3 shows an example of orbit of the secondary electrons when the secondary electron conversing electrode 33 is grounded for comparison. Since the potential beam is parallel with the secondary electron conversing electrode 33 in an area close to the detector (referred to as “Area I”), the secondary electrons emitted from the Area 1 are strongly affected by the force directed towards the sample from the deflection electric field. As a result, the secondary electrons do not enter the detector and hit the lower part of the cover of the detector, resulting in a lower efficiency of detecting the secondary electrons in the Area 1. In an area far apart from the detector (referred to as “Area II”), as the secondary electrons emitted in the opposite direction from the detector collide with the electrode 62, the efficiency of detecting the secondary electrons decreases in the Area II. Therefore, there are differences in the efficiency of detecting the secondary electrons in the surface of the secondary electrons conversion electrode, and it becomes uneven. When the sample is observed at a low magnification, the secondary electrons are intensely deflected by the scanning deflector, and scan the secondary electron conversing electrode 33. When the scope of scanning includes the Area I and II where the efficiency of detection has declined, there are differences in the efficiency of detecting the secondary electrons depending on the place of scanning, and this can be the cause of development of shading (spots of brightness) on the acquired image. If any shading appears, due to the use of difference information of contrast between the normal part and the defective part in the judgment of defects, normal inspections cannot be performed. Accordingly, in this embodiment, as shown in FIGS. 1 and 2, the voltage control means 37 is used to apply voltage on the secondary electron conversing electrode 33, to control the potential at a level higher than the electrodes 62a and 62b and to adjust thus the equipotential distribution, and thus to create the force for pulling up the secondary electrons towards the conversion electrode. In this way, the secondary electrons that collide with the lower part of the cover for the detector and the electrode 61 and are not absorbed by the detector advance between the secondary electron conversing electrode 33 and the grounded electrode 67. FIG. 4 shows an example of orbit of the secondary electrons when a voltage is applied to the secondary electron conversing electrode 33. As FIG. 4 shows clearly, the deflected secondary electrons penetrate the mesh deflection electrode 60, are accelerated by the electric field created by the extraction electrode 39, hit the fluorescent body 38, and excite the fluorescent body to generate light. The detector 40 detects this light. The E×B deflector 31 orthogonalizes the deflection electric field and the deflection magnetic field so that there may be no deflection action on the primary electrons. It generates, however, a deflection chromatic aberration in the primary electron beam having an energy width of (ΔV0). The quantity of deflection ΔxLC of the primary electrons having an energy of V0+ΔV0 at a place separated by LL from the center of the deflector is expressed by the equation (2). [Equation 2] Δ ⁢ ⁢ x LC = ( 1 L × L L d L × V L V 0 + Δ ⁢ ⁢ V 0 - 2 ⁢ e m × B L × 1 L × L L V 0 + Δ ⁢ ⁢ V 0 ) Equation ⁢ ⁢ ( 2 ) Another deflector whose polarity is inverted is arranged for correcting the deflection aberration. In other words, the length of the deflection electrode of the E×B deflector 32 for correcting deflection aberration is set at 2×Iu, the distance between deflection electrodes is set at du, −Vu/2 is applied on the deflection electrode in the deflection direction of the secondary electrons, and +Vu/2 is applied on the symmetric deflection electrode, and the intensity of the deflection magnetic field is set at Bu. The quantity of deflection of ΔxUC of the primary electrons mentioned above at a location separated by Lu from the center of the deflector to the sample side is expressed by the equation (3). [Equation 3] Δ ⁢ ⁢ x UC = - ( 1 U × L U d U × V U V 0 + Δ ⁢ ⁢ V 0 - 2 ⁢ e m × B U × 1 U × L U V 0 + Δ ⁢ ⁢ V 0 ) Equation ⁢ ⁢ ( 3 ) The total sum of the quantity of deflection of the upper and lower deflectors is the total sum of the equation (2) and the equation (3). [Equation 4] Δ ⁢ ⁢ x = ( 1 L × L L d L × V L V 0 + Δ ⁢ ⁢ V 0 - 2 ⁢ e m × B L × 1 L × L L V 0 + Δ ⁢ ⁢ V 0 ) - ( 1 U × L U d U × V U V 0 + Δ ⁢ ⁢ V 0 - 2 ⁢ e m × B U × 1 U × L U V 0 + Δ ⁢ ⁢ V 0 ) Equation ⁢ ⁢ ( 4 ) It is possible to reduce deflection chromatic aberration by setting the length of the deflection electrode and the voltage to be applied in such a way that the value of equation (4) may be zero. Incidentally, the energy width of the primary electron beam is determined by the electron source 1, and the energy width of the electron source Zr/0/W used in this embodiment is evaluated at 0.6 eV. This primary electron beam passing through the condenser lens 6 creates a crossover point between the deflectors 31, 32 and the scanning deflector 7. The primary electron beam having an energy of (V0+ΔV0) has the total sum Δx of the deflection quantity of the upper and lower deflectors and the total sum Δθ of deflection angle of the upper and lower deflectors at the crossover point. In this embodiment, the secondary electron conversing electrode 33 and two deflectors are connected each other through an insulator. The two deflectors are arranged at close positions, and as the distance between the crossover point and the respective deflector is approximately the same, it is possible to correct both Δθ and Δx, and the primary electron beam penetrates vertically the center of the objective lens and pass through the same. Generally, when the primary electron beam enters a electromagnetic lens with an angle, an aberration develops out of axis. However, in order to reduce aberration with an objective lens for which an electromagnetic lens is used, it is necessary to inject the primary electron beam vertically into the objective lens 8. As stated above, the configuration of this embodiment that enables to inject the primary electron beam vertically along the center of the objective lens 8 enables to cancel deflection chromatic aberration with a good precision even if an electromagnetic lens is used for the objective lens 8 shown in FIG. 1. FIG. 5 shows a second embodiment. The configuration of this embodiment is a configuration in which the position of the deflector 31 and that of the deflector 32 in the first embodiment are switched. FIG. 5 shows the same configuration as that of the first embodiment except the position of the deflector 31 and the deflector 32. The configuration of the second embodiment is characterized in that the deflector 31 for deflecting the secondary electrons is located closer to the side of the electron source than the deflector 32 for correcting aberration and is connected with the secondary electron conversing electrode 33 through an insulator. The deflector 31 and the deflector 32 are connected through an insulator, and are operated in such a way that their polarity of deflection may be reverse. In the first place, the secondary electrons are deflected by the deflection field created by the deflector 32 for correcting aberration. After passing through the deflection field mentioned above, they are deflected by the deflection field created by the deflector 31 for deflecting the secondary electrons. The direction of deflection by these two deflectors is directly opposite because the polarity of deflection of the two deflectors is reversed, and the quantity of deflection cancels each other. Since the action of deflection for the secondary electrons remains unchanged and the action of correcting aberration for the primary electron beam also remains unchanged, the effect will be, like the first embodiment, that the efficiency of detecting the secondary electrons will be high and uniform in the surface of the secondary electron conversing electrode. And the effect of correcting deflection aberration for the primary electrons can be obtained in the same way as in the first embodiment. Then, we will describe a third embodiment. While, in the first embodiment, the whole secondary electron conversing electrode was set in a same potential, in this embodiment, a secondary electron conversing electrode 33′ having a structure capable of changing continuously potential is used as the secondary electron conversing electrode. We will describe the secondary electron conversing electrode 33′ of this embodiment with reference to FIG. 6. It is the same as the first embodiment except the structure of the secondary electron conversing electrode. In the first place, a thin metal foil having an equivalent dimension and shape as the surface area of the secondary electron conversing electrode is divided and cut out into n pieces. The direction of cutting is in the parallel direction with the y axis. And the greater the value of n is, the better. The cut out metal foils will be pasted on the surface of the secondary electron conversing electrode in such a way that they may not contact each other, and the adjacent metal foils are connected with resistances. Therefore, n pieces of metal foils are connected in series by using n−1 pieces of resistances (Ω). All the n−1 pieces of resistances to use shall be those having the same resistance value. Incidentally, the secondary electron conversing electrode 33′ shall have an opening for allowing the passage of primary electron beam at its center. When a potential V1 is applied to the electrode 60 of the deflector 31 and a potential V2 is applied to the electrode 61, a power source shall be arranged in such a way that the deflection electric field electrode 60 side of the metal foil pasted on the surface of the secondary electron conversing electrode 33 may be V1 and the deflection electric field electrode 61 side may be V2. Since the metal foils are connected in series, potentials of (V1−V2)/n will be distributed. According to the above-mentioned configuration of this embodiment, the equipotential beam of the deflection electric field is vertical to the secondary electron conversing electrode, as shown in the first embodiment the secondary electrons will be absorbed into the detector without any loss. Then, as the fourth embodiment of the present invention, we will show in FIG. 7 an example of carrying out the present invention in a semiconductor dimension measurement scanning electron microscope (dimension measurement SEM) for measuring the dimension of semiconductor patterns. If there is any shading on the acquired image (or two-dimensional distribution information of pixels) for measuring the dimension and inspecting semiconductor patterns, it is impossible to precisely measure the dimension and evaluate semiconductor patterns. Therefore, the configuration of this embodiment is effective. This embodiment shows an example of carrying out the present invention in a scanning electron microscope having a semi-in-lens objective lens. The dimension measurement SEM can be broadly divided into the electron optical system, the sample chamber 327, the control unit 326, and the electron detection system. The electron optical system includes an electron gun 301, an extraction electrode 302, an acceleration electrode 303, condenser lens 304 and 306, an aperture diaphragm 305, a scanning deflector 307, an objective lens 308, and an objective lens upper magnetic electrode 313. The sample chamber 327 includes a stage 309. The objective lens upper magnetic electrode 313 includes a variable voltage booster voltage power source 312, and the stage 309 includes a variable voltage retarding voltage power source 311. The electron detection system includes E×B detectors 331 and 332, a secondary electron conversing electrode 333, and a secondary electron detector 334. The secondary electron conversing electrode 333 is connected with a voltage power source 337. The detected signals are transmitted to the transmitted signals processer 324 for measurement of dimensions. The images taken in are displayed on the monitor 325. The operation commands and operation conditions for various parts of the apparatus are inputted and outputted in and from the control unit 326. As FIG. 8 shows, the E×B deflector 331 includes four electrodes 360, 361, 362a and 362b for creating a deflection electric field, four coils 363a, 363b, 363c and 363d for creating a deflection magnetic field, a ground electrode 367 and insulators 366a and 366b. The electrode 360 is connected with a voltage power source 364 so that a positive voltage may be applied thereto, and the electrode 361 is connected with a voltage power source 365 so that a negative voltage may be applied thereto. The electrode 361 may sometimes be grounded. The electrodes 362a and 362b are grounded. The E×B deflector 332 includes four electrodes 370, 371, 372a and 372b for creating deflection electric field, four coils 373a, 373b, 373c and 373d for creating deflection magnetic field, a ground electrode 377 and insulators 376a and 376b. The electrode 370 is connected with a voltage power source 374 so that a negative voltage may be applied thereto, and the electrode 371 is connected with a voltage power source 375 so that a positive voltage may be applied thereto. The electrode 371 may sometimes be grounded. The electrodes 372a and 372b are grounded. The secondary electron conversing electrode 333 is connected with the voltage power source 337, and it is connected with the E×B deflector 331 through an insulator 336a, and with the E×B deflector 332 through an insulator 376a. The two E×B deflectors 331 and 332 are connected on the same axis with the opening for allowing the passage of the primary electron beam as its central axis. The secondary electron detector 334 includes a fluorescent body 338, a secondary electron suction high-voltage electrode 339, and a detector 340. The electron gun 301 includes an extraction electrode 302, and the primary electron beam is extracted from the electron gun by applying voltage on the extraction electrode 302. For the electron source of the electron gun 301, a diffusion supply-type thermal field emission electron source Zr/O/W is used. A negative voltage −V0 is applied on the acceleration electrode 303, and the primary electron beam passes through the acceleration electrode 303 with an energy V0. In this embodiment, we chose 3 kV for V0. Then, it is converged by the condenser lens 304 to create a crossover point 314. The condenser lens 304 is connected with the condenser lens power source 320, and the control unit 326 controls its operation. And its current is restricted while it passes through the aperture diaphragm 305. And the primary electron beam is converged in the condenser lens 306, to create a crossover point 315. The condenser lens 306 is connected with the condenser lens power source 321, and the control unit 326 controls its operation. The condenser lens 304 and the condenser lens 306 are controlled in such a way that the crossover point 315 may be situated between the E×B deflector 331 and the scanning deflector 307. The primary electron beam is narrowed down sharply by an objective lens having an objective lens power source 323 controlled by the control unit 326. The stage 309 includes a variable voltage retarding voltage power source 311 so that the high-voltage potential for decelerating the primary electron beam −Vr (retarding potential) may be variable. Due to the retarding potential, the primary electron beam, being abruptly decelerated directly above the sample, is converged by the objective lens on the sample. And the deflection coil 307 disposed in two stages between the condenser lens and the objective lens causes the primary electron beam to scan the substrate to be inspected 310. The scanning deflector 307 is connected with the scanning signal generator 322, and the control unit 326 controls its operation. At the time of irradiation of samples, the energy of the primary electron beam is (V0−Vr). Like the first embodiment, by the irradiation of the primary electron beam, the sample 310 generates secondary electrons having an energy of approximately zero to 50 eV and reflected electrons having an energy higher than 50 eV. The objective lens upper magnetic electrode 313 includes a variable voltage booster voltage power source 312 so that a positive potential for pulling up the secondary electrons (booster potential Vb) may be applied thereto, and the secondary electrons are pulled up to the electron source side by the booster potential. Since we chose 2.2 kV for Vr in this embodiment, the primary electron beam penetrates the sample with an energy of 800 eV. We chose 6 kV for Vb. The secondary electrons advance to the electron source side being wound up to the electron source side by the pull-up electric field created by the booster electrode and the magnetic field created by the objective lens. Due to the absence of stereoimage detector for detecting reflected electrons, and a high value of Vb in comparison with the first embodiment, there are a large number of secondary electrons pulled up to the electron source side. Between the condenser lens 306 and the objective lens, a secondary electron conversing electrode 333, being a discoidal electrode having a central hole for allowing the passage of the primary electron beam, is provided. The secondary electron conversing electrode 333 includes a means for applying voltage, and phosphor bronze is used for the material because of ease of acquisition and processing. Other materials may be used. The surface is coated with gold mainly for the purpose of preventing polluting materials from sticking thereon due to the irradiation of the secondary electron beam. Other materials may be used for the coasting material. The secondary electron conversing electrode 333 is connected with the deflector 331 for deflecting secondary electrons on the sample side through an insulator, and with a deflector 332 for canceling the aberration of the primary electron beam on the electron source side through an insulator. The embodiment of various deflectors is the same as the first embodiment. The secondary electrons collide with the secondary electron conversing electrode 333, from which the secondary electrons are generated. By the deflection field of the deflector 331, the secondary electrons are deflected in the direction of the detector, infiltrate a mesh electrode 360 and enter the detector 340 being accelerated by the suction electrode 339. Also in this embodiment, like the cause of generation of shading described in the first embodiment, if the secondary electron conversing electrode has no means of applying voltage, the efficiency of detecting the secondary electrons varies depending on the position where the secondary electrons collide with the secondary electron conversing electrode 333, and the efficiency of detecting the secondary electrons becomes uneven in the surface of the secondary electron conversing electrode. When we observe samples at a low magnification, the secondary electrons are largely deflected by the scanning deflector, and if there is any area where the efficiency of detection has fallen down in the scope of scanning while we are scanning the secondary electron conversing electrode 333, the efficiency of detecting the secondary electrons varies depending on the position of scanning. This constitutes a cause for the appearance of shading on the acquired images. The presence of shadings on the acquired image constitutes a cause that cannot be measured correctly in the dimension measurement SEM for evaluating the dimension of semiconductor patterns from the acquired image. Therefore, a voltage is applied on the secondary electron conversing electrode 333 by the controlling means of voltage 337, and the voltage is controlled at a level higher than the electrodes 362a and 362b to adjust the equipotential distribution. Thus, the force is created for pulling up the secondary electrons towards the conversion electrode. In this way, the secondary electrons that collided with the cover beneath the detector or the electrode 361 and were not absorbed by the detector advance between the secondary electron conversing electrode 333 and the grounded electrode 367. Incidentally, the embodiment of the deflector is similar to the first embodiment, and its structure is shown in FIG. 8. Since the structure is the same, the deflection action on the primary electron beam and the deflection action on the secondary electron are similar to the first embodiment, and in addition as the two deflectors having reverse deflection polarity are joined respectively through the secondary electron conversing electrode and an insulator, the correction of deflection aberration by the deflectors vis-à-vis the primary electron beam can obviously be obtained in the same way as the first embodiment.
	description	This invention relates to particle beam therapy system in which a particle beam is applied such as performing cancer treatment by irradiating a particle beam. Irradiation method of particle beam therapy system is divided broadly into two methods. That is, a broad irradiation method in which a beam is irradiated into whole of patient's affected area simultaneously and a scanning irradiation method in which a beam is scanned and irradiated. In order to realize a broad beam irradiation method and a scanning irradiation method, equipment and controlling methods which are suited for the irradiation methods are required. Regarding irradiation apparatuses which are used for conventional scanning irradiation methods, in order to increase accuracy of irradiation position of patient's affected area, a configuration, in which a vacuum region or a region of gas which is lighter than air such as helium is secured and scattering of a beam is suppressed so as to reduce a size of a beam, has been proposed. A part in which a vacuum region or a gas region is secured is indicated as a chamber (beam transport chamber, gas chamber, etc.), or a duct (vacuum duct, etc.). In order to irradiate a beam having a small spot size, an irradiation apparatus which is used for a scanning irradiation method should have a configuration such that a scattering of a beam in a path, before an irradiation object (isocenter) which is caused by air has to be suppressed. Therefore, according to the configuration, right up to an irradiation position is a vacuum region or a gas region, and substances which scatter a beam including an isolation window (beam outlet window) in the region are arranged in the most downstream which is close to an irradiation object. Further, regarding a broad beam irradiation method, equipment including a spread out Bragg peak forming filter, a collimator and a bolus should be installed in an irradiation apparatus. By using the equipment, an energy distribution of a beam and a beam shape are formed so as to form a particle beam irradiation filed which is suited to a shape of an affected area. According to a broad beam irradiation method, an irradiation field is formed by scattering a particle beam; therefore, it is not necessary to suppress a spot size to be small. Consequently, unlike an irradiation system apparatus which is used for a scanning irradiation method, it is not required to have the configuration such that a vacuum duct is arranged right up to an irradiation object so as to suppress a scattering caused by air in an irradiation apparatus. As above mentioned, a configuration of a scanning irradiation method and that of a broad beam irradiation are different, therefore, it is difficult to realize a plurality of irradiation methods at one irradiation unit. These irradiation methods have different characteristics and depending on an irradiation part and a shape of an affected part, suited irradiation method is different. As a configuration for realizing a scanning irradiation method and a broad beam irradiation method, Patent Document 1 discloses a configuration, that is, a plurality of treatment rooms are provided, in some of the treatment rooms, an irradiation apparatus of a scanning irradiation method is installed, and in other treatment rooms, an irradiation apparatus of a broad beam irradiation method is installed. However, according to the above-mentioned method, an irradiation unit is required for each irradiation method, therefore, cost as a whole of system is increased. As a configuration for resolving the above-mentioned points, Patent Document 2 discloses a configuration, that is, a gas chamber for suppressing scatter of a particle beam is made to be extendable in the beam traveling direction, and in space which is made by contracting the gas chamber, equipment which is necessary for a broad beam irradiation are inserted so as to enable to realize a broad beam irradiation in the same irradiation unit. Patent Document 1: JP 2007-268031A Patent Document 2: JP 2010-17365A Non-Patent Document 1: “Design and construction of a ripple filter for a smoothed depth dose distribution in conformal particle therapy”, Uli Weber and Gerhard Kraft, Phys. Med. Biol. 44 (1999) 2765-2775 Here, a spread out Bragg peak forming filter (hereinafter, will be referred to as a ridge filter) will be described. A ridge filter has a configuration such that is a necessary number of a bar ridge which is generally made of aluminum, brass, etc. and has a mountain-shaped cross-section are arranged so as to form an irradiation field. Regarding the ridge filter in order to obtain a flat spread out Bragg peak region, processing in several hundred micro meter to several ten micro meter order accuracy is required to form an inclined plane of the bar ridge. Therefore, it requires extremely long time (=cost) to manufacture a bar ridge having a long depth and height. Consequently, it is preferable such that a size of a ridge filter (Length: L, height: h) is small and pitch: λ of bar ridges is large. In order to make a size of a ridge filter to be small, it is necessary to arrange a ridge filter itself apart from an irradiation object as far as possible. Further, in order to make a pitch: λof bar ridges to be large, it is necessary to arrange a ridge filter apart from an irradiation object. In Non-Patent Document 1, the above-mentioned relationship between a distance to an irradiation object and a pitch of bar ridges was described in detail. Here, a problem regarding the configuration which was cited in Patent Document 2 will be described. According to the configuration disclosed in Patent Document 2, equipment which is used for a broad beam irradiation method is inserted in space which is made by contracting a gas chamber. However, in a case where a telescopic gas chamber is used, according to the configuration of the gas chamber, even where a gas chamber is contracted at a maximum, an area which is occupied by the gas chamber is not zero. Therefore, the gas chamber is positioned on a beam line. In order to reduce the size, Patent Document 2 proposes a telescopic mechanism of a cylindrical gas chamber in which the cylindrical gas chamber is divided by some sections so as to make outer shape to be larger toward downstream. However, in order to shorten a length of a gas chamber in a beam direction when the gas chamber is contracted, it is necessary to increase a number of sections for dividing. As the number of dividing increases, an outer shape of the gas chamber becomes extremely larger than a size which is necessary for passing a beam. Therefore, it is necessary for the configuration for inserting equipment which is used for a broad beam irradiation to arrange in a position having no interference with the gas chamber. Consequently, a distance which is necessary for switching of equipment becomes longer. In a case where a vacuum bellows, etc. is used in stead of a gas chamber is used, the same problem is generated. In a case where a vacuum bellows is used, it is considered such that the condition becomes worse than a case where a gas chamber is used. (In a case of a vacuum bellows, even when a bellows is contracted, the length is substantially half of full length.) Because of the above-mentioned reason, according to equipment layout of Patent Document 2 when a broad beam irradiation is performed, a position of a ridge filter is extremely apart from a scanning electromagnet by an installation space of a gas chamber. As above mentioned, it is necessary to keep a distance between a ridge filter and an irradiation object, as a result, large space for arranging equipment which is necessary for irradiation is required. This invention relates to a particle beam therapy system which realizes a plurality of irradiation methods by one irradiation nozzle in a particle beam therapy system which is used for cancer treatment. In order to solve the above-mentioned problems of conventional apparatus, this invention aims to provide a particle beam therapy system which can use a ridge filter which can be manufactured easily even when space between a scanning electromagnet and an irradiation object is small. According to this invention, in a particle beam therapy system comprising a scanning electromagnet for irradiation an irradiation object by scanning a particle beam which travels in a vacuum duct, and an irradiation unit having a beam outlet window from which a particle beam comes out from a vacuum duct to the atmosphere, wherein the irradiation unit has the configuration such that a vacuum duct is provided which can be divided by a flange surface at an irradiation object side than a scanning electrode, in a case where a vacuum duct for a scanning irradiation method which is provided at an irradiation object side than a flange surface is moved so as not to overlap with a beam line of a particle beam, a ridge filter for a broad beam irradiation method can be provided in space which is on a beam line of a particle beam and where the vacuum duct for a scanning irradiation method was provided before it was moved. According to a particle beam therapy system of this invention, when equipment configuration is switched from that of a scanning irradiation method to that of a broad beam irradiation method, a ridge filter which is required for a broad beam irradiation method can be provided in the vicinity of a scanning electromagnet, therefore, a ridge filter, which can be manufactured easily even in a case where space from a scanning electromagnet to an irradiation object is small, can be used. Embodiment 1 FIG. 1 is a front view showing a configuration of an irradiation unit which is a main unit of a particle beam therapy system according to Embodiment 1 of this invention. FIG. 2 is a schematic bird's-eye view showing an example of whole configuration of a particle beam therapy system to which this invention is applied. In FIG. 2, a particle beam which is generated and pre-accelerated by a pre-accelerator 16 enters an accelerator (syncrotron) 14 so as to be accelerated to be necessary beam energy, and is extracted from an extracting deflector to a beam transport unit 17, reaches an irradiation unit 18 and irradiates an affected part of a patient which is an irradiation object. The beam transport unit 17 comprises a bending electromagnet 12, 13 and a vacuum duct 15, etc. In FIG. 2, at a position of the bending electromagnet 13, a beam transport system is branched, and one of the beam transport system connects to a rotating gantry 19. A part of the beam transport unit 17 and an irradiation unit 18a are mounted on the rotating gantry 19. By rotating the rotating gantry 19, an irradiation direction of the irradiation unit 18a can be changed. An irradiation unit 18b which is connected to other part of the branched beam transport system is not mounted on a rotating gantry, however, the configuration of the irradiation unit 18a and that of the irradiation unit 18b are basically same. Here, the irradiation units 18a and 18b are referred to collectively as the irradiation unit 18. FIG. 1 shows the configuration in a case where a scanning irradiation method is performed. In FIG. 1, a particle beam which is extracted from the accelerator 14 is transported in the vacuum duct 15. In the irradiation unit 18, the particle beam passes through a vacuum duct 4 which secures a vacuum region and is communicated and a vacuum duct for a scanning irradiation method 6. And then, the particle beam comes out from a beam outlet window 7a to the atmosphere so as to irradiate an affected part which is an irradiation object. In FIG. 1, only an isocenter 11 which is a reference position of an affected part is shown. A particle beam scans an irradiation object with scanning electromagnets 5a and 5b (which are collectively referred to as a scanning electromagnet 5). The irradiation unit 18 comprises a vacuum duct transfer mechanism 60 for evacuating the vacuum duct for a scanning irradiation method 6 from a beam line 1 (a center of the beam line is indicated by reference note 1 with alternate long and short dash line), in order to switch a configuration of equipment arrangement of a scanning irradiation method to that of equipment arrangement of a broad beam irradiation method, a connection flange surface 47 with the vacuum duct 4,a gate valve 48 of the vacuum duct 4 for dividing a vacuum region just before the scanning electromagnet 5 and a scatterer 41 for scattering a particle beam in accordance with an irradiation field. Further, the irradiation unit 18 comprises a ridge filter 42 for spreading out Bragg peak of a particle beam in a depth direction and a range shifter 43 for adjusting a range of a particle beam. Here, the ridge filter 42 and the range shifter 43 are attached to a ridge filter transfer mechanism 61 so as to be able to transfer to a direction which is parallel with a beam line 1. Next, operation will be described. In a case where an irradiation is performed by a scanning irradiation method by a particle beam therapy system according to EMBODIMENT 1, in order to reduce a spot size of a beam at a beam irradiation position by suppressing scattering of a particle beam as far as possible, the particle beam therapy system has the configuration such that a vacuum duct is arranged right up to a beam irradiation position. Here, a scatterer 41 is not required, therefore, the scatterer 41 is made to evacuate at a side of the beam line 1. In a case where a particle beam is a proton beam, in a scanning irradiation method, a ridge filter 42 is not required, however, in other particle beams, in some cases, a ridge filter is used for enlarging slightly an energy width. For example, in a case of heavy particle beam such as a carbon beam, a Bragg peak width is extremely sharp in comparison with that of a proton beam. Therefore, in order to reduce an irradiation time, in some cases, a ridge filter is used for forming a spread out Bragg peak (SOBP) having a certain size (several mm) so as to irradiate to a certain depth width in one scanning. However, in this case, the ridge filter is for spreading a width of a SOBP to be several mm, and a height of bar ridges may be shorter than a width of the SOBP. Even in a case where an arrangement position is not far from an irradiation object, a ridge filter, which can be manufactured easily than a ridge filter for broad beam, can be used. Further, a reach depth of a particle beam (range distance) is determined by energy of a particle beam; therefore, it is required to change energy of a particle beam so as to change a range distance of an energy beam. When energy is changed only by adjusting energy of an accelerator, it takes time for switching energy. Therefore, in some cases, a range shifter for reducing energy of a particle beam is used so as to change energy of a particle beam. A particle beam may be scattered by a range shifter. When the above-mentioned is taken into account, it is preferable such that a range shifter is arranged at a downstream side as far as possible, that is, at a position as close as possible to an irradiation object. Consequently, in a case where the ridge filter 42 or the ridge shifter 43 is used, an arrangement shown in FIG. 1 is preferable. Next, a case where irradiation method is switched from a scanning irradiation method to a broad beam irradiation method will be described. FIG. 3 shows the state of an irradiation unit shown in FIG. 1 in which an irradiation method is switched from a scanning irradiation method to a broad beam irradiation. In a scanning irradiation method, a particle beam therapy system has the configuration such that a vacuum duct for scanning irradiation method 6 is arranged at a position which is close to an irradiation position so as not to enlarge a beam spot size. On the other hand, in a broad beam irradiation method, it is necessary to enlarge an energy width of a particle beam. Therefore, it is necessary to arrange the ridge filter 42 at a position which is away from an irradiation object. In a particle beam therapy system according to EMBODIMENT 1, all of the vacuum ducts for scanning irradiation method 6 which are provided at downstream of the scanning electromagnet 5 are removed so as to evacuate from a position on the beam line 1. As a result, large space can be secured. FIG. 1 shows the configuration in which the vacuum duct for scanning irradiation method 6 can be separated from the vacuum duct 4 by a flange surface 47 which is provided at downstream of the scanning electromagnet 5. Further, the particle beam therapy system has the configuration such that when the vacuum duct for scanning irradiation method 6 is removed from a flange, by a driving base which receives the vacuum duct for scanning irradiation method 6 and a vacuum duct transfer mechanism 60 having a driving rail, the vacuum duct for scanning irradiation method 6 is slid, and evacuated easily from a position on the beam line 1 so as not to overlap with the beam line 1. After the vacuum ducts for scanning irradiation method 6 is removed, the vacuum duct connecting flange surface 47 is a final surface, therefore, as shown in FIG. 3, a beam outlet window 7b is attached on the flange surface 47. In space which is generated by sliding the vacuum duct for scanning irradiation method 6 by the vacuum duct transfer mechanism 60, the ridge filter 42 is transferred by a ridge filter transfer mechanism 61 in a direction close to the flange surface 47, raised to a position which is just below the beam outlet window 7b, and installed. In this time, the ridge filter 42 is switched from that for a scanning irradiation method to that for a broad beam irradiation method. Further, the range shifter 43 is transferred up and down as appropriate, and a bolus 44 and a patient collimator 45 are placed as appropriate. Further, when a scanning irradiation method is performed, the scatter 41 which was evacuated from a position on the beam line 1 is transferred to a position on the beam line 1. By performing the above-mentioned, a broad beam irradiation can be performed. By the configuration in which the bolus 44 and the patient collimator 45 are attached to a lower surface of the range shifter 43 by attaching a holder for insertion with a rail, the bolus 44 and the patient collimator 45 can be installed easily. Further, the ridge filter 42 and the range shifter 43 can be inserted by using a linear driving mechanism or a rotary driving mechanism using air or a motor. Further, according to the above-mentioned configuration, the vacuum ducts for scanning irradiation method 6 is evacuated by sliding, however, a method, in which a rotary supporting mechanism is provided and a flange and insertion space are switched by rotating a supporting mechanism, can be realized. In a case where a vacuum separation surface is not provided at a position which is upper stream than the vacuum duct for scanning irradiation method 6, and the vacuum duct for scanning irradiation method 6 is communicated from upstream, by removing the vacuum duct for scanning irradiation method 6, all of vacuum of beam transport system is broken. In this case, it takes time for increasing a degree of vacuum; therefore, it is preferable such that a gate valve is arranged at a position which is just upstream of the scanning electromagnet 5. The gate valve 48 may be arranged just downstream of the scanning electromagnet 5. When the vacuum duct for scanning irradiation method 6 is removed, by closing the gate valve 48, influence to a degree of vacuum can be suppressed only in an area which is downstream than the gate valve 48. When the gate valve 48 serves a function of a final beam outlet window, it is not necessary to attach the beam outlet window 7b, therefore, switching can be performed in shorter time. As above-mentioned, according to EMBODIMENT 1, in a broad beam irradiation method, the vacuum duct for scanning irradiation method 6 which is used for a scanning irradiation method is evacuated so as not to overlap with a beam line 1 through which a beam passes, and in vacant space, the ridge filter 42 is transferred in a direction of the beam line so as to arrange. Consequently, the ridge filter 42 can be arranged at a position which is away from an irradiation object, whole of irradiation unit can be formed compactly and a ridge filter which can be easily manufactured can be used. Embodiment 2 FIG. 4 and FIG. 5 are views showing the configuration of an irradiation unit which is a main unit of a particle beam therapy system according to EMBODIMENT 2. FIG. 4 shows the configuration in a case where a scanning irradiation method is performed in a particle beam therapy system according to EMBODIMENT 2. According to EMBODIMENT 1, a scanning irradiation method has the configuration in which a ridge filter is used. In a case where an irradiation is performed by a scanning irradiation method, scattering of a beam of a particle beam is suppressed as much as possible so as to reduce a size of a beam spot at a beam irradiation position. Consequently, in many cases, a particle beam therapy system has the configuration such that a vacuum duct is arranged right up to a beam irradiation position as shown in FIG. 4. In this time, a scatterer 41, a ridge filter 42 and a range shifter 43 are not required; therefore, the scatterer 41, the ridge filter 42 and the range shifter 43 are evacuated so as not to overlap with a beam line 1. Next, in EMBODIMENT 2, a method in which equipment configuration of a scanning irradiation method is switched to that of a broad beam irradiation method will be described. In a scanning irradiation method, in order to reduce a beam spot size, a particle beam therapy system has the configuration such that a vacuum duct is arranged right up to an irradiation position. However, according to the above-mentioned configuration, there is not any space for arranging a ridge filter, etc. which is used for a broad beam irradiation method. In a case where a ridge filter, etc. is arranged with the arrangement of a vacuum duct for scanning irradiation method 6 as shown in FIG. 4 as it is, a ridge filter is arranged in space at downstream of the vacuum duct for scanning irradiation method 6 (before an irradiation position). Consequently, a distance to an irradiation object is short, as a result, it is difficult to manufacture a ridge filter which can be used in this distance. According to Patent Document 2, space for arranging an apparatus is generated by contracting a gas chamber. However, according to EMBODIMENT 2, a particle beam therapy system has the configuration such that the vacuum duct for scanning irradiation method 6 which is arranged at downstream of a scanning electromagnet 5 is removed and evacuated so as to secure space which is much larger than space disclosed in Patent Document 2. In FIG. 4, the vacuum duct for scanning irradiation method 6 has the configuration such that the vacuum duct for scanning irradiation method 6 can be separated from a vacuum duct 4 at a flange surface 47 which is downstream of the scanning electromagnet 5. Further, the particle beam therapy system has the configuration such that when the vacuum duct for scanning irradiation method 6 is removed from a flange, by a driving base which receives the vacuum ducts and a vacuum duct transfer mechanism 60 having a driving rail, the vacuum duct for scanning irradiation method 6 is slid and evacuated easily from a position on the beam line 1 so as not to overlap with the beam line 1. FIG. 5 shows the configuration in which an irradiation method is switched to a broad beam irradiation method in EMBODIMENT 2. After the vacuum duct for scanning irradiation method 6 is removed, a vacuum duct connecting flange surface 47 is a final surface, therefore, as shown in FIG. 3, a beam outlet window 7b is attached on the flange surface 47. In space which is generated by sliding the vacuum duct for scanning irradiation method 6, the ridge filter 42 and the range shifter 43 are inserted. Further, the scatter 41 which was evacuated from a position on the beam line 1 when a scanning irradiation method was performed is transferred to a position on the beam line 1. Further, as appropriate, by attaching a bolus 44 and a patient collimator 45, a broad beam irradiation can be performed. By the configuration in which the bolus 44 and the patient collimator 45 are attached to an lower surface of the range shifter 43 by attaching a holder for insertion with a rail, the bolus 44 and the patient collimator 45 can be installed easily. Further, the ridge filter 42 and the range shifter 43 can be inserted by using a linear driving mechanism or a rotary driving mechanism using air or a motor. Further, according to the above-mentioned configuration, the vacuum duct for scanning irradiation method 6 is evacuated by sliding, however, a method, in which a rotary supporting mechanism is provided and a flange and insertion space is switched by rotating the supporting mechanism, can be realized. As above-mentioned, according to EMBODIMENT 2, in a broad beam irradiation method, the vacuum duct for scanning irradiation method 6 which is used for a scanning irradiation method is evacuated so as not to overlap with a beam line 1 through which a beam passes, and in vacant space, the ridge filter 42 is inserted. Consequently, the ridge filter 42 can be arranged at a position which is away from an irradiation object, whole of irradiation unit can be formed compactly and a ridge filter which can be easily manufactured can be used. Embodiment 3 FIG. 6 and FIG. 7 are views showing the configuration of an irradiation unit which is a main unit of a particle beam therapy system according to Embodiment 3 of this invention. FIG. 7 is a cross-sectional view taken on line A-A of FIG. 6. According to the configuration of EMBODIMENT 1 and EMBODIMENT 2, in a case of a scanning irradiation method, a position of a beam outlet window is determined by a length of a vacuum duct for scanning irradiation method 6, therefore, a position of the beam outlet window can not be adjusted according to a size of an irradiation object. However, in a case of a scanning irradiation method, a spot size is reduced to be as small as possible, therefore, it is preferable such that a position of the beam outlet window is made to be closer to an irradiation object as much as possible. According to EMBODIMENT 3, the configuration in which a height of the beam outlet window can be changed can be realized. By referring to FIG. 6 and FIG. 7, an irradiation unit of a particle beam therapy system according to EMBODIMENT 3 will be described. According to EMBODIMENT 3, a particle beam therapy system has the characteristic such that the system comprises a rotating disk type vacuum duct support mechanism 62 for holding a plurality of vacuum ducts for scanning irradiation method 6a, 6b and 6c having a different length. First, in FIG. 6 and FIG. 7, the vacuum duct for scanning irradiation method 6a which is attached on a beam line 1 is removed and slid by a vacuum duct transferring mechanism 63 so as to evacuate to vacant space of the rotating disk type vacuum duct support mechanism 62 for holding the vacuum duct for scanning irradiation method 6a at a position where the position does not overlap with the beam line 1. After that, the rotating disk type vacuum duct support mechanism 62 is rotated so as to set at an angle by which a vacuum duct for scanning irradiation method having a length which is different from that of the vacuum duct for scanning irradiation method 6a, for example, the vacuum duct for scanning irradiation method 6b can be provided. By setting the above-mentioned, by the vacuum duct transferring mechanism 63, the vacuum duct for scanning irradiation method 6b having a different length can be transferred on the beam line 1. By attaching the vacuum duct for scanning irradiation method 6b to a connecting flange surface 47, a height of a beam outlet window 7a can be changed. In FIG. 7, a case where three types of vacuum duct are arranged is described, however, by enlarging a size of rotating disk; a number of types of vacuum duct whose length can be changed can be increased. Further, by providing a ridge filter transfer mechanism 61 which was described in EMBODIMENT 1, after a height of a beam outlet window is changed, a position of a ridge filter and that of a range shifter can be changed according to a height of the beam outlet window. In EMBODIMENT 3, as a supporting mechanism for holding a plurality of vacuum ducts for scanning irradiation method at a position where a beam line 1 does not overlap is described. In addition to the above-mentioned, as a supporting mechanism for holding a plurality of vacuum ducts for scanning irradiation method at a position where a beam line 1 does not overlap, a length of a vacuum duct can be changed in the same way as that of the above-mentioned, by making the configuration in which a plurality of branching points at a side of evacuation of a vacuum duct transfer mechanism are provided, or making the configuration in which a vacuum duct can be divided in a direction of the beam line 1 so as to provide a vacuum duct transfer mechanism at each dividing unit. Embodiment 4 As an irradiation unit 18a which is mounted on a rotating gantry 19 shown in FIG. 1, one of irradiation units 18 which were described in the EMBODIMENTs 1 to 3 can be applied. Generally, irradiation of a particle beam is performed while a rotating gantry is stopped. In a case where one of irradiation units 18 which were described in EMBODIMENTs 1 to 3 is mounted on a rotating gantry, it is preferable from a view point of operation such that transferring operation of a vacuum duct is performed at zero degree of gantry angle (an angle where an irradiation unit is arranged vertically). 1: beam line 4, 15: vacuum duct 6, 61, 6b, 6c: vacuum duct for a scanning irradiation method 5, 5a, 5b: scanning electromagnet 7a, 7b: beam outlet window 11: isocenter 12, 13: bending electromagnet 14: accelerator 17: beam transport unit 18, 18a, 18b: irradiation unit 19: rotating gantry 41: scatterer 42: ridge filter 43: range shifter 44: bolus 45: patient collimator 47: flange surface 48: gate valve 60, 63: vacuum duct transfer mechanism 61: ridge filter transfer mechanism 62: rotating disk type vacuum duct support mechanism
	summary
	abstract	Using a beam current of an ion beam, a dose amount to a substrate, and a reference scan speed, a scan number of the substrate is calculated as an integer value in which digits after a decimal point are truncated. If the scan number is smaller than 2, the process is aborted. If the scan number is equal to or larger than 2, it is determined whether the scan number is even or odd. If the scan number is even, the current scan number is set as a practical scan number. If the scan number is odd, an even scan number which is smaller by 1 than the odd scan number is obtained, and the obtained even scan number is set as a practical scan number. A practical scan speed of the substrate is calculated by using the practical scan number, the beam current, and the dose amount.
046613064	abstract	Apparatus is disclosed for introducing a low neutron moderating fluid into the reactor vessel of a spectral shift pressurized water nuclear reactor and for distributing the moderating fluid through the lower core support plate into the fuel assemblies in the core.

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