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047939478	description	DESCRIPTION OF THE PREFERRED EMBODIMENTS The basic principle of the present invention is first described. Radioactive wastes produced from nuclear power plants, etc., are mostly composed of the substances shown in Table 1. TABLE 1 ______________________________________ Classification of radioactive wastes Source of generation Waste ______________________________________ BWR power plants Sulfuric acid (H.sub.2 SO.sub.4) Sodium hydroxide (NaOH) PWR power plants Boric acid (H.sub.3 BO.sub.3) Nuclear fuel reprocessing Nitric acid (HNO.sub.3) plants Sodium hydroxide (NaOH) ______________________________________ Thus, radioactive wastes can be classified into two types: acidic wastes and basic wastes. Usually, in consideration of corrosiveness of the storage tank, the waste liquids are stored in the state of being neutralized with each other or by further adding a basic substance. Whether neutralized or not, radioactive waste liquid contains only a few percent of solid radioactive material called "crud" including iron rust, and all of the principal components shown in Table 1 stay dissolved in the form of ions. For reducing the volume of such radioactive waste liquid, it has been practiced in the past to dry the waste liquid by a dryer to remove water therefrom to form a solid mass of the ions which have stayed dissolved in the waste liquid. This method, however, although high in the volume reducing effect, requires a high equipment cost as a dryer is needed. Also, since the solid mass produced by drying is still a soluble matter, it is necessary to give consideration to the possible elution of radioactive waste material. As a solution to this problem, the present inventors hatched an idea of rendering the ionic matter in the waste liquid into an insoluble salt or adding to the waste liquid a solid substance which is capable of adsorbing the ionic matter to thereby remove the ionic matter from the waste liquid in the form of a precipitate (or sediment). If the ionic matter in the radioactive waste liquid is settled into an insoluble precipitate, the remaining solution is neutral water alone and therefore it can be easily separated from the precipitate. According to this method, no drying step is required and also since the separated precipitate is formed as an insoluble matter, it is possible to eliminate any adverse effect of the sediment to the solidifying agent at the time of solidification and to also perfectly prevent the elution of radioactive waste material from the solidified body, i.e. the waste package. The basic principle in converting the ionic matter in radioactive waste liquid into an insoluble precipitate according to the present invention is now described. Regarding the individual ionic materials existing in waste liquid, for example, in sulfuric acid waste liquid from BWR power plants, there exist in such waste liquid sulfuric acid ions (SO.sub.4.sup.2-) and hydrogen ions (H.sup.+) as cations. To such system is added a substance which is combined with said ions to form an insoluble salt. For instance, ions of an alkaline earth metal (such as Ca.sup.2+, Ba.sup.2+, etc.) are added to the sulfuric acid ions (SO.sub.4.sup.2-) to cause a reaction of the following formula through which said sulfuric acid ions are made into an insoluble salt and deposited. ##STR2## Since hydrogen ions (H.sup.+) cannot be sedimented, hydroxyl ions (OH.sup.-) are added to convert such hydrogen ions into ordinary water. Generally, it is impossible to add ions alone into the solution, so that it needs to select a substance which is capable of giving said both cations and anions at the same time. In the above instance, both alkaline earth metal ions and hydroxyl ions can be added simultaneously by adding a hydroxide of an alkaline earth metal, for example, barium hydroxide (Ba(OH).sub.2). The reaction rate is unchanged no matter whether said barium hydroxide is added in the form of an aqueous solution or in the form of powder, and the reaction can be completed in a few minutes. By this method, the anions (sulfuric acid ions) can be settled into precipitate while the cations are made into water, and the precipitate alone needs to be solidified. In the ordinary nuclear power plants, however, waste liquid is stored not in said state of sulfuric acid but in the form of a neutral solution formed by adding a basic substance such as sodium hydroxide. In this case, the ionic substances which exist in waste liquid are sulfuric acid ions (SO.sub.4.sup.2-) and sodium ions (Na.sup.+). If alkaline earth metal ions are added to this system, the sulfuric acid ions are made into an insoluble precipitate in the way illustrated by formula (1). In this case, alkaline earth metal ions may be added in the form of a salt such as hydrochloride, nitrate, etc., or in the form of hydroxide. Addition in the form of a salt, however, is undesirable because of the possibility that there might be produced a soluble sodium salt bonded with sodium ions. Therefore, addition in the form of hydroxide is preferred. When said alkaline earth metal ions are added in the form of hydroxide, sodium hydroxide is produced beside the insoluble precipitate from the reaction shown by formula (3): ##STR3## If sodium hydroxide is removed by means of adsorption in the manner described below, the remaining waste liquid can be made into ordinary water. Also, by adding silicic acid (H.sub.2 SiO.sub.3) to NaOH, it is possible to synthesize water glass, and such water glass can be utilized as a solidifying agent for the waste material. FIG. 2 shows the conversion rate in the reaction of formula (3) when barium hydroxide and calcium hydroxide were added severally to the aqueous solution of sodium sulfate. In case of adding barium hydroxide, 100% conversion can be achieved by the reaction of one hour at 80.degree. C. In the case of calcium hydroxide, the conversion lowers to a fraction of the rate achievable in the case of barium hydroxide, and accordingly a longer time is required for the reaction, resulting in an increased processing cost. Thus, use of barium hydroxide is preferred. As for the kind of alkaline earth metal to be added, barium, calcium, strontium and magnesium are preferred in that order. The hydroxide of alkaline earth metal may be added either in the form of powder or as a solution thereof, but the former is preferred as a smaller capacity is required for the reaction vessel used. In case of adding powder, since the reaction starts after the powder was once dissolved in water to form alkaline earth metal ions, there is required water of at least an amount necessary for dissolving the powder, but this poses no problem as the concentration of waste liquid to be treated is usually of the order of 20% by weight. When barium hydroxide is added to a concentrated waste liquid mainly composed of sodium sulfate, insoluble barium sulfate is produced and the concentrated waste liquid becomes white turbid. This white turbidity occurs as the particles of barium sulfate exist in a suspended state, but the liquid does not become viscous and is capable of easy filtration. The solid matter which remains after the filtration contains barium sulfate produced by the insolubilization reaction and iron oxides called radioactive crud from nuclear power plants. The same holds true in case the main component of concentrated waste liquid is sodium borate or sodium sulfate. This solid matter may be stored in the form as it is, but preferably it is solidified with a suitable solidifying agent such as cement, water glass or plastic and stored as a solidified body of waste package. On the other hand, the filtrate, which becomes a sodium hydroxide solution, may be recovered as is, but when a solid substance which adsorbs sodium ions and is deposited is added, said sodium hydroxide solution can be resolved into a precipitate and ordinary water. For realizing this, however, the solid substance added needs to be the one which is capable of adsorbing sodium ions while releasing hydrogen ions. Ion exchange resin is a typical example of such substance. The present inventors found that the used ion exchange resin which is discharged as a waste material from nuclear power plants can be used for said purpose because such used ion exchange resin, when discharged out, still maintains more than 90% of its normal ion exchange capacity. The present invention is thus a very significant attainment from the aspect of volume reduction of radioactive wastes. The cation exchange resin which accounts for two thirds of the used ion exchange resin adsorbs cations such as sodium ions and releases hydrogen ions. Thus, when ion exchange resin is added to said sodium hydroxide solution, sodium ions are adsorbed by said resin while hydroxy ions are reduced into ordinary water through the following reaction: ##STR4## Since the reaction of formula (4) occurs very rapidly, it suffices to sufficiently mix the solid-state ion exchange resin and the sodium hydroxide solution. Alternatively, said ion exchange resin may be previously filled in a cylindrical object and the sodium hydroxide solution is passed through such cylindrical object. The used ion exchange resin discharged from nuclear power plants is either powdery (particle size being around 40 .mu.m) or granular (particle size being around 500 .mu.m). Both forms of resin can be used for the purpose of this invention. Beside such used ion exchange resin, a used filter aid (such as cellulose fiber) is also usable for said purpose. FIG. 3 shows the reduction of NaOH by the addition of ion exchange resin to the sodium hydroxide solution. It was observed that the amount of NaOH was reduced in accordance with the reaction of formula (4), and at the point when the amount of ion exchange resin added became 2.3 times by weight the initial amount of NaOH (that is, when the amount of ion exchange resin became 70% as against 30% of NaOH), NaOH was perfectly eliminated and the solution became ordinary water. Separation of solid-state ion exchange resin and water is easy. Also, since the metal ions of radioactive nuclides such as cobalt, cesium, manganese, etc., are adsorbed in the ion exchange resin, there scarecely exists radioactivity in the ordinary water separated from the ion exchange resin. Therefore, the separated water may be released to the living environment or evaporated if the measured value of radioactivity thereof is below the prescribed level. On the other hand, the ion exchange resin which has adsorbed sodium and radioactive nuclides is preferably solidified with an inorganic solidifying agent such as cement or sodium silicate. Generally, ion exchange resin has a high water absorptivity, and in case a simple method such as precipitation method is used for its separation from water as mentioned above, it can not be sufficiently dehydrated and the particles thereof contain a fairly large amount of water in the inside. Therefore, in case of using plastic for solidifying the resin, the hardening thereof is obstructed by the water remaining in the inside of the resin particles to retard the solidification. However, in case of using an inorganic solidifying agent, there is no necessity of giving consideration to the remaining water in the resin. Cement and sodium silicate (water glass), which are the typical examples of inorganic solidifying agent, are themselves a hydraulic solidifying agent which requires water when solidified, so that it is expedient to separate the ion exchange resin in a water-containing state and add cement powder thereto to effect solidification. Solidification can be also effected by adding powdery sodium silicate and its hardening agent, in place of cement. In this case, a more compact solidified body can be obtained. This NaOH adsorbing process by use of ion exchange resin is preferably carried out successively to the anion sedimentation process for achieving an efficient treatment of radioactive waste. That is, a substance (such as barium hydroxide) which is combined with anions to form an insoluble salt is added to the radioactive waste liquid principally composed of sodium sulfate, thereby settling the anions into a sediment, and then a solid-state substance (such as ion exchange resin) which adsorbs cations is added to the solution to settle the remaining cations in the solution while turning the residual waste liquid into neutral water. According to this method, precipitation of both anions and cations in the radioactive waste liquid can be accomplished in a single reaction vessel. The precipitate formed is a mixture of the precipitated anions and cations, so that solidification of such mixture provides a greater effect of volume reduction of the waste than in case the respective precipitates of anions and cations are solidified individually. As the solid substance for adsorbing the cations and settling them, there can be used the used ion exchange resin, which is a radioactive waste material, or a used filter aid, but such substance lowers the strength of the solidified body because of low modulus of elasticity. Therefore, the packing rate of ion exchange resin, etc., is strictly regulated for meeting the strength requirement of the solidified body that it must have a uniaxial compression strength of at least 150 kg/cm.sup.2. Consequently, a substantial portion of the produced solidified body is occupied by the ion exchange resin. On the other hand, the sediment or precipitate of anions is high in moduuus of elasticity because of the ion crystalline salt such as barium sulfate, and hence such sediment increases the strength of the solidified body. So, when said two types of precipitate are mixed and solidified, there is produced a solidified body in which barium sulfate of high modulus of elasticity fills up the areas around the particles of ion exchange resin of low modulus of elasticity as shown in FIG. 4. Therefore, such solidified body has a greater strength than the solidified body formed by using an ion exchange resin alone. As a result, the packing rate of ion exchange resin can be improved, and further, since the precipitate of the substance (barium sulfate) combined with anions is solidified simultaneously with the ion exchange resin, it becomes unnecessary to form a solidified body of the precipitate of barium sulfate, etc. Thus, the present invention can realize a striking waste volume reducing effect. FIG. 5 graphically illustrates the strength of the solidified body made by adding barium sulfate to ion exchange resin. In the illustrated examples, sodium silicate (water glass) was used as solidifying agent. In the graph of FIG. 5, curve A shows the uniaxial compressive strength of the solidified body made by solidifying resin alone with the solidifying agent, curve B represents the result obtained when barium sulfate alone was solidified with the solidifying agent, and curve C represents the case where a 7:3 mixture of resin and barium sulfate was solidified with the solidifying agent. From the comparison of curves A and C, it is seen that the produced solidified body has a greater strength when a mixture of resin and barium sulfate is used for forming a solidified body than when resin alone is used. Thus, according to the present invention, the packing rate of the waste material can be improved by an amount corresponding to the improvement of strength of the solidified body. It will be seen that the maximum waste packing rate for satisfying the standard uniaxial compressive strength of 150 kg/cm.sup.2 of the solidified body is approximately 25% in the case of curve A, whereas it can be increased up to about 40% in the case of curve C. As described above, the present invention is capable of not only simplifying the radioactive waste treating process but also remarkably reducing the volume of waste by treating together the radioactive waste liquid and used ion exchange resin released from nuclear power plants. In the present invention, in case the radioactive waste liquid to be treated is an aqueous solution of neutral salt of sodium sulfate, etc., there is required the used ion exchange resin of the amount which is 2 to 3 times by weight the solid matter (including dissolved ions) in the radioactive waste liquid for effecting adsorption and settling of the cations. In view of the fact that the rate of generation of used ion exchange resin in the existing nuclear power plants, especially BWR power plants, is increasing every year, the present invention is advantageous in this respect, too. The present invention will be further described with reference to the concrete examples of the invention. EXAMPLE 1 Treated in this example is a concentrated radioactive waste liquid principally composed of sodium sulfate and discharged from a boiling-water type nuclear power plant. Sulfuric acid ions in the waste liquid are deposited as barium sulfate and the remaining sodium ions in said waste liquid are deposited by having them adsorbed on the particles of used ion exchange resin to thereby reform the waste liquid into ordinayy water. This water is separated from the mixture of said two type of sediment, and the water-free mixture is solidified with an inorganic solidifying agent. A flow chart of the treating system in this example of the invention is shown in FIG. 1. The concentrated waste liquid principally composed of sodium sulfate (hereinafter referred to simply as concentrated waste liquid) 1 is a mixture of sodium hydroxide and sulfuric acid produced when regenerating the ion exchange resin in a condensing desalting apparatus, the mixture being concentrated to a concentration of about 20-25% by weight. This concentrated waste liquid 1 is stored in tank 4 and supplied to reactor 11 after passing through valve 7. Powder of barium hydroxide 2 stored in tank 5 is also supplied to said reactor 11 through valve 8. The feed of barium hydroxide is preferably equimolar to sodium sulfate in the concentrated waste liquid. In other words, powder of barium hydroxide is added in an amount of approximately 53 kg to 200 liters of the 20% concentrated waste liquid. Reactor 11 having said supplied concentrated waste liquid and barium hydroxide mixed therein is kept at 80.degree. C. by heater 20 and sufficiently stirred and mixed for about one hour by stirrer 53. The solution in reactor 11 becomes cloudy with generation of barium sulfate. The pH of the solution also rises to about 13 due to formation of barium hydroxide. A small portion was collected from said cloudy solution and filtered to separate into solid matter and liquid, and the solid matter was analyzed by X-ray diffractometry while the liquid by atomic-absorption spectroscopy. The analyses confirmed that the solid matter was barium sulfate and the liquid was sodium hydroxide. Then used ion exchange resin 3 stored in tank 6 is supplied into said cloudy solution 10 in reactor 11 through valve 9. The amount of said used ion exchange resin supplied is such that it is sufficient to adsorb the sodium ions in said cloudy solution. To be concrete, said resin is supplied in an amount of approximately 150 kg on the dry basis (1,500 kg as solution). Said amount of resin sufficient to adsorb sodium ions in the cloudy solution is explained in more concrete terms. The amount of resin to be added for sufficiently adsorbing sodium ions depends on the amount of sodium sulfate in the concentrated waste liquid. Regarding such sodium sulfate, the sulfuric acid ions are settled and sedimented by barium hydroxide in the first stage of this invention, and in the second stage the sodium ions in the by-produced sodium hydroxide are adsorbed by the resin. ##STR5## Thus, supposing that the initial dry weight of sodium sulfate is x kg, barium hydroxide is added in an amount of 1.92 kg in the sedimentation reaction of the first stage, and the resin is added in an amount of 3x kg in the sodium ion adsorption reaction of the second stage. Regarding the resin, since the used ion exchange resin is used, it is duly expected that the exchange capacity of the resin would be slightly reduced. The calculations were made here on the supposition that the used resin maintained 80% of the exchange capacity of the normal resin. In the actual operations, for giving latitude, it is advisable to add the resin in an amount of 3x kg plus 10-20% extra. After supply of the used ion exchange resin, the materials in reactor 11 are stirred and mixed for about one hour. Reactor 11 needn't be heated during this mixing operation. By approximately one hour stirring and mixing, sodium ions in the solution are completely adsorbed by the ion exchange resin and the solution is made into ordinary water, with a pH of 6-8. Then stirring in reactor 11 is stopped and the mixture is allowed to stand as it is for about 3hours. Consequently, solid matter 12 settles down at the bottom of the reactor and the supernatant becomes transparent water. The amounts of solid matter and water can be easily calculated as the sedimentation reaction by barium hydroxide and the adsorption of sodium ions by the used ion exchange resin take place at an almost 100% efficiency. In the instant example, the amount of the sediment was about 230 kg and water was about 1,500 kg The sediment was a mixture of 71 kg of barium sulfate and 159 kg of sodium-adsorbed ion exchange resin. Then the supernatant (water) is removed from reactor 11 by pump 13. It is to be noted that 1,300 kg of water is removed, leaving in the reactor 200 kg of water which is necessary for the solidification of the sediment. The radioactivity in the removed water was below 10.sup.-5 .mu.Ci/cc, which assures safe release of removed water into the living environment. The residual sediment 12 and water in reactor 11 are stirred and mixed by stirrer 53 to form a slurry. This slurry of sediment 12 and water is supplied into 200-liter drums 19 through valve 14. 215 kg of slurry is supplied into each drum. Also supplied into each drum is 145 kg of mixture of powdery sodium silicate and its powdery hardening agent stored in tank 16 (said mixture being hereinafter referred to as water glass solidifying agent). The feed of said water glass solidifying agent is calculated by load cell 17. The water glass solidifying agent supplied into drum 19 is sufficiently mixed with said slurry by stirrer 54, and the mixture is allowed to stand at room temperature to solidify by itself. There were produced two solidified bodies (each packed in a drum) in this example. After one-month curing, the properties of the solidified body were examined. The solidified body had a sectional structure as shown in FIG. 4, in which the BaSO.sub.4 particles 61 filled the areas surrounding the granules of ion exchange resin 60, and they were in a state of being fixed and solidified in the solidifying agent 15. Both resin 60 and BaSO.sub.4 particles 61 were seen dispersed quite uniformly. Also, the solidified body had a sufficient strength, with its uniaxial compressive strength being over 150 kg/cm.sup.2. As described above, according to this example of the invention, the concentrated waste liquid and the used ion exchange resin are treated through a sedimentation process, so that the waste disposal is greatly simplified and it also becomes possible to realize a substantial volume reduction of the waste and to obtain the strong solidified bodies of waste material. By using the processing apparatus of FIG. 1, there were produced the solidified bodies according to the same process as in the preceeding example except that cement was used as solidifying agent. The obtained solidified bodies were as strong as those obtained in the preceeding example where water glass was used as solidifying agent. Two solidified bodies were obtained in this case, too. Then, the water resistance of said solidified bodies made by using cement and water glass as solidifying agent, respectively, was examined. Cylindrical samples of 20 mm in diameter and 40 mm in height were obtained from the respective solidified bodies by core sampling, and these samples were immersed in 500 ml of deionized water and their weight change was measured, obtaining the results shown in FIG. 6. The solidified body obtained by using cement as solidifying agent suffered absolutely no weight change as shown by straight line 71, indicating the very excellent water resistance of this solidified body. On the other hand, the solidified body made by using water glass solidifying agent had an approximately 3% loss of weight in the initial phase of immersion but thereafter suffered no weight reduction as shown by curve 72. It was confirmed by analyzing the immersion water that the weight loss in the initial phase of immersion was due to the elution of disodium hydrogenphosphate (Na.sub.2 HPO.sub.4) by-produced when water glass was hardened. However, no noteworthy problem arises from such degree of elution of disodium hydrogenphosphate from the solidified body made by using water glass solidifying agent. More significant is the fact that it has been confirmed that the solidified body made by using water glass solidifying agent is less in the rate of elution of radioactivity, by about one order, than the solidified body made by using cement (see The Proceedings of the Fall Subcommittee Meeting of Japan Atomic Energy Society, 1984, G38). The foregoing results confirm that according to the present invention, there can be produced a solidified body of radioactive waste with extremely high water resistance, whether cement or water glass is used as solidifying agent. EXAMPLE 2 This example employs the same process as Example 1 for treating the concentrated waste liquid to form a sediment of barium sulfate, but in this example, sodium silicate (water glass) is synthesized from sodium ions and the dry powder of said two materials (barium sulfate and sodium silicate) is mixed with the dry powder of ion exchange resin and the mixture is solidified in a drum. FIG. 7 illustrates a flow chart of the processing system used in this example. Concentrated waste liquid 1 stored in tank 4 is supplied into reactor 11 through valve 7. Then barium hydroxide 2 stored in tank 5 is charged into said concentrated waste liquid in reactor 11 through valve 8. The amounts of said concentrated waste liquid and barium hydroxide supplied are the same as in Example 1. The mixture of concentrated waste liquid and barium hydroxide in said reactor 11 is kept at 80.degree. C. by heater 20 and stirred by stirrer 53 for about one hour. After this one-hour stirring, the solution was found turned into a sediment of barium hydroxide and an aqueous solution of sodium hydroxide. Then, with the inside of reactor 11 kept at 80.degree. C., silicic acid 23 stored in tank 27 was supplied into said reactor 11 through valve 31 and reacted for about 2 hours under stirring by stirrer 53. The feed of silicic acid 23 was about 1.5 times the feed of barium hydroxide. Immediately after supply of silicic acid, the solution in reactor 11 was in such a state that the particles of silicic acid were dispersed in the solution, but silicic acid was gradually reacted with sodium hydroxide as shown by formula (5) below to produce sodium silicate (water glass). In two hours, the reaction was totally completed and the particles of silicic acid disappeared. ##STR6## As a result, there was produced a mixture 33 of sediment of barium sulfate and solution of water glass in the reactor. This mixture 33 is then supplied to rotary vane evaporator 37 through valve 36. Said mixture 33 is dried and powdered in said evaporator 37, then passed through branching valve 38 and stored in tank 41 as mixed powder 39. It was confirmed that this mixed powder 39 was composed of barium sulfate and powder of sodium silicate (water glass). The slurry of used ion exchange resin 3 stored in tank 6 is dried and powdered separately from said mixture 33. That is, when valve 36 is closed, valve 9 is opened to supply said slurry of ion exchange resin 3 into said rotary vane evaporator 37 where said slurry is dried and powdered, then passed through branching valve 38 and stored in tank 42. Then, 140 kg of mixed powder 39 and 80 kg of resin powder 40 are supplied into drum 19 through valves 47 and 48, respectively, and mixed together in said drmm. Thereafter, about 40 kg of hardening agent 43 is supplied into said drum from tank 45 through valve 49, with simultaneous supply of about 80 kg of water 44 from water tank 46 through valve 50. The mixture of the supplied materials is stirred in drum 19 by stirrer 54 for a few minutes to form a pasty mixture 51 and the latter is left as it is to let it cure and solidify by itself. The obtained solidified body after one-month curing had excellent water resistance and high strength as the one produced in Example 1. It was thus confirmed that the objective solidified body with sufficiently high strength can be produced by using water glass prepared in this example (synthesized by reactor 11) as solidifying agent. Also, since the water glass prepared in this example is synthesized by adding silicic acid (H.sub.2 SiO.sub.3) to sodium hydroxide (NaOH) which is by-produced when forming the sediment of barium sulfate by adding barium hydroxide to the concentrated waste liquid, it is possible to synthesize water glass of any desire composition by properly adjusting the amount of silicic aiid added. Generally, water glass is represented by the chemical formula Na.sub.2 O.nSiO.sub.2, and its composition is usually expressed by weight ratio of silicon oxide (SiO.sub.2) and sodium oxide (Na.sub.2 O). By using the apparatus shown in FIG. 7, there were produced the solidified bodies in the same way as described above but by changing the amount of silicic acid 23 added, and their strength was measured, obtaining the results shown in FIG. 8. In the graph of FIG. 8, the water glass composition (SiO.sub.2 /Na.sub.2 O) was plotted as abscissa and the measured uniaxial compressive strength of the produced solidified bodies as ordinate. As seen from the graph, the solidified body strength is greatly affected by the water glass composition. It is also seen that the water glass composition that can provide the uniaxial compressive strength of 150 kg/cm.sup.2 or above, which is the lowest allowable strength of solidified body of waste for ocean dumping thereof, is in the range where SiO.sub.2 /Na.sub.2 O.apprxeq.1 to 4 by weight ratio. Thus, it is recommended to add silicic acid in an amount that would produce the water glass composition (SiO.sub.2 /Na.sub.2 O) of said range. FIG. 9 shows the results of measurement of water resistance of the solidified bodies made by changing the water glass composition in otherwise the same way a described above and immersed in water. In FIG. 9, the water glass composition is represented by SiO.sub.2 /Na.sub.2 O ratio by weight on the horizontal axis and the weight decreasing rate of solidified body on the vertical axis. It is seen from the graph of FIG. 9 that the water resistance is improved as the proportion of SiO.sub.2 in the composition increases, but the water resistance becomes constant when the SiO.sub.2 /Na.sub.2 O ratio becomes 1 or greater. This can be accounted for by the fact that SiO.sub.2 is insoluble in itself and forms the main structure of the solidified body while Na.sub.2 O tends to form a soluble salt, so that the increase of Na.sub.2 O invites a drop of water resistance. In relation to the optimal range of uniaxial compressive strength shown in FIG. 8, it is advised to select the SiO.sub.2 /Na.sub.2 O ratio from the range of 1-4. Further, by using the processing apparatus of FIG. 7, there were produced the various solidified bodies by changing the mixing ratio of mixed powder 39 of powdered barium sulfate and water glass and powder of ion exchange resin 40, and their strength was measured. As a result, it was found that the uniaxial compressive strength of solidified body greatly depends on the amount of resin in the solidified body. That is, the strength of solidified body lowers as the ratio of resin increases and the strength rises as the ratio of resin decreases. Since the solidified body is essentially required to have a uniaxial compressive strength of 150 kg/cm.sup.2 or above, the waste packing rate is reduced when the resin content in the waste is high, but the packing rate can be increased when the resin content is low. FIG. 10 is a graph showing the production ratio of the drums (solidified bodies) when the solidified bodies satisfying the uniaxial compressive strength of 150 kg/cm.sup.2 were produced by changing the ratio of resin powder to the mixed powder of waste (mixture of resin powder and barium sulfate) and water glass. As seen from this graph, in the present invention the production ratio of drums was the lowest when the ratio of resin powder to barium sulfate was 40-70% as shown by curve D. In case the resin powder and the mixed powder of barium sulfate and water glass were solidified severally from each other, the production ratio of drums (shown by line E) was always higher than in case the solidified bodies were produced according to the method of this invention (curve D). In the case of the present invention, as shown by curve D, the production ratio of drums is the lowest, that is, the waste packing rate per drum is the highest, when the resin content in the waste is around 40- 50%. This is due to the following reason. In Example 2, the sodium hydroxide (NaOH) produced in the process of conversion of the concentrated waste liquid into a sediment of barium sulfate is entirely altered into water glass serving as solidifying agent, so that the production of water glass is decided according to the amount of concentrated waste liquid. Thus, the ratio of water glass becomes higher than barium sulfate more than necessary, so that although the strength of solidified body becomes higher than 150 kg/cm.sup.2, the waste packing rate is reduced to the order of 30% by weight. When the resin content in the waste is increased by adding resin powder to barium sulfate and its ratio reaches 40-50% by weight, the amount of water glass produced becomes such amount that can provide the solidified body strength of just 150 kg/cm.sup.2. Since resin powder has been added by an amount corresponding to the reduction of produced water glass, the waste packing rate per drum becomes the highest. In BWR nuclear power plants, the rate of generation of barium sulfate to resin is approximately 3:7, so that if the ratio of resin is selected to be 70% by weight in the practice of this example of the invention, the waste treatment process is simplified. In this case, the waste packing rate is slightly lowered as indicated by point d on curve D. This is because the generation of water glass is reduced and it is required to add water glass from the outside for satisfying the solidified body strength of 150 kg/cm.sup.2. In case barium sulfate and resin are solidified severally, the number of the drums produced becomes always higher than in the case of the present invention. This is due to the fact that in case resin is solidified individually, the maximum waste packing rate that can satisfy the solidified body strength of 150 kg/cm is about 25% by weight as shown by curve A in FIG. 5, and in case barium sulfate is treated individually, the amount of water glass generated becomes superfluous as mentioned before, compelling a reduction of the maximum allowable barium sulfate packing rate to about 30% by weight. EXAMPLE 3 This example is illustrated in FIG. 11. In this example, the concentrated waste liquid is first deposited in the form of a sediment of barium sulfate, and then resin is added to let it adsorb NaOH in the remaining liquid. Some NaOH will remain only in case the amount of resin added is not sufficient to adsorb the entirety of NaOH. In this case, silicic acid 23 is supplied from tank 27 into reactor 11 where NaOH remains to synthesize a solidifying agent (water glass). As a result, there remains in reactor 11 an aqueous solution containing insolubilized barium sulfate, inactivated resin and water glass. Then the material from this reactor 11 is supplied into centrifugal thin-film dryer 37 where said material is dried and powdered and then solidified by adding a solidifying agent, a hardening agent and water. Since the solidifying agent already exists (synthesized water glass) in the dry powder, the solidifying agent is added only to supply the shortage in the solidifying step. The reaction product in the reactor may be made into a slurry by a concentrator, instead of drying and powdering it. In this case, it is unnecessary to add water in the solidifying step. In this example, since silicic acid is added to form water glass in case the amount of resin is short, there is provided a processing system that can accommodate itself to the variation of the amount of resin. In FIG. 11, the parts indicated by the same reference numerals as used in FIGS. 1 and 7 denote the same or corresponding parts in said Figures. EXAMPLE 4 This example concerns the case where the present invention was applied to the treatment of waste liquid composed of sodium borate generated from PWR nuclear power plants. In this example, the insolubilization reaction progresses in the way expressed by the following formula: ##STR7## Barium borate (BaB.sub.4 O.sub.7) is also an insoluble sediment, and therefore the insolubilization can be accomplished in the same way as in the case of waste liquid composed of sodium sulfate. In this case, however, there is a possibility that the reaction solution becomes viscous to defy sedimentation unless the process is carried out at a temperature above 60.degree. C., preferably around 80.degree. C. Other treatments can be accomplished in the completely same way as in preceeding Examples 1-3. EXAMPLE 5 Discussed here is the case where sodium sulfate waste liquid generated from nuclear fuel reprocessing plants is treated. In this case, the insolubilization reaction advances as follows: EQU 2NaNO.sub.3 +Ba(OH).sub.2 .fwdarw.Ba(NO.sub.3).sub.2 +2NaOH (8) Insolubilization can be accomplished extensively with Ba(NO.sub.3).sub.2, too, as its solubility is below 1/10 of that of NaNO.sub.3. Sedimentation can be also easily accomplished at normal temperature. Other processes can be carried out with ease after the manner of Examples 1-3 described above. EXAMPLE 6 In case of using an ion exchange resin having about 10 times greater exchange capacity than the presently used ones or in case the amount of concentrated waste liquid generated is only about 1/10 of the ordinary level, it is possible to accomplish insolubilizatoon without adding barium hydroxide because, in such cases, both anions and cations in the waste liquid can be entirely adsorbed by the ion exchange resin. According to this example, there is no need of adding barium hydroxide and the radioactive waste can be made into an insoluble sediment only by using an ion exchange resin. Also, when the waste liquid is treated with an additive, or a mixture of two or more miscible additives, which is capable of turning sulfuric acid ions and alkali metal ions into an insoluble sediment, addition of ion exchange resin 3 in said Examples 1-3 becomes unnecessary. According to this example, processing of waste liquid is possible without relying on the waste treating capacity of the ion exchange resin. The additives usable in this example include commercially available phosphorus-free detergent builders (hard water softening agent). A typical example of such phosphorus-free builders is synthetic zeolite, and this substance is considered to be an inorganic ion exchanger. If barium ions are beforehand adsorbed on this synthetic zeolite, it can adsorb sodium ions in the presence of a large quantity of sodium ions and releases barium ions. This enables simultaneous conversion of both sulfuric acid ions and sodium ions into insoluble substance. Other additive than said synthetic zeolite can be similarly applied to the process of this example if there is available such additive which is capable of simultaneous conversion of sulfuric acid ions and sodium ions into insoluble precipitate. As described above, in accordance with the present invention, it is possible to carry out processing and disposal of radioactive waste liquid and used ion exchange resin in an in-line system, and the processing steps and apparatus can be greatly simplified. It is further possible according to this invention to produce a waste package of radioactive waste with high strength and water resistance and to also attain a sizable reduction of the volume of radioactive waste.
	summary
	claims	1. A method for testing the seal of a glove which is installed in a particular port of an isolator, comprising:providing a test disc having a seal for connecting to the port in a hermetically sealed fashion, the test disc having a pressure-measuring device, a microprocessor, a memory and a data interface for transmission of information, the test disc further including a reading device configured to determine an identity of the particular isolator port;sealing an open end of a glove between the test disc and port so as to define an internal glove volume, the glove having a first identification element;placing the glove volume under excess pressure;measuring the glove volume pressure with the pressure-measuring device of the test disc;recording and storing a glove volume pressure profile with the microprocessor and memory;reading the first identification element of the glove with the reading device of the test disc to determine a glove identity; andstoring both the identity of the glove and the identity of the particular isolator port in the memory. 2. The method of claim 1, further including measuring the glove volume pressure over a predefined time period and comparing any pressure drop with a limiting value. 3. The method of claim 1, further including correlating historical data on previous tests of the glove and estimating a residual period of use of the glove therefrom. 4. The method of claim 1, further including simultaneously receiving the pressure profiles for a plurality of gloves from a plurality of test discs, and assigning the respective pressure profiles to a corresponding glove and port. 5. The method of claim 1, further including preventing removal of the test disc from the port if a defect in the glove is detected. 6. The method of claim 1, further including recording an early pressure profile for a specific glove at a relatively early point in time and comparing the early pressure profile with a later pressure profile which is recorded for this glove at a relatively late point in time, and estimating a residual period of use of the glove from the comparison. 7. The method of claim 1, further including providing an evaluation unit comprising a memory unit and an output unit connected to a user database, and transmitting the pressure profile with the identities of a corresponding glove and port to the evaluation unit, and estimating a residual period of use of the glove therefrom. 8. The method of claim 7, wherein the transmission of the pressure profile with the identities of a corresponding glove and port to the evaluation unit are done wirelessly. 9. The method of claim 7, wherein process-related data about the use of the glove is stored in the evaluation unit and taken into account during the estimation. 10. The method of claim 1, further including providing an identification element for the port of the isolator which can be read by the reading device of the test disc.
050733338	claims	1. A method of decontaminating radio nuclide-contaminated corrosion products, which are insoluble or sparingly soluble in acids, from primary systems surfaces in nuclear reactors of the pressurized water type, the boiler reactor type with hydrogen dosage and similar, especially for the decontamination for the purpose of demolishing or scrapping such reactors or components thereof, where the contaminated surfaces are contacted with an oxidation agent in an acid solution so as to obtain an oxidation in the presence of Ce.sup.4+ ions, ozone and chromic acid, and the corrosion products which have been made acid soluble by means of said oxidation are dissolved, characterized by performing said oxidation with Ce.sup.4+ ions, ozone and chromic acid with concentrations thereof required for said decontamination, in the presence of perhalogen acid at a pH below 3. 2. A method according to claim 1, characterized by performing said oxidation in the presence of Ce.sup.4+ in a concentration of 0.01-50 g/l, ozone in a concentration of 0.001-1 g/l and chromic acid in a concentration of 0.001-50 g/l. 3. A method according to claim 1, characterized by using as said cerium compound cerium perhalogenate perchlorate, or cerium nitrate. 4. A method according to claim 1, characterized by performing said oxidation in the presence of perhalogen acid in such a concentration that the pH value is below 2. 5. A method according to claim 1, characterized by performing said oxidation with perhalogen acid having a molarity within the range of 0.01-8M. 6. A method according to claim 1, characterized by using as said oxidizing agent an acidic aqueous solution of Ce.sup.4+ and chromic acid as well as ozone in a saturated solution and dispersed form. 7. A method according to claim 1, characterized by using as said oxidation agent a two-phase ozone gas-aqueous mixture where ozone in gaseous form has been dispersed in an acidic aqueous solution of Ce.sup.4+ and chromic acid. 8. A method according to claim 1, characterized by performing the oxidation and dissolution in one and the same step. 9. A method according to claim 1, characterized by performing the oxidation and dissolution at a temperature below about 60.degree. C. 10. A method according to claim 1, characterized by performing the oxidation with an external addition of chromic acid to the oxidation solution. 11. A method according to claim 1, characterized by performing said oxidation in the presence of Ce.sup.4+ in a concentration of 0.5-10 g/l, ozone in a concentration of 0.001-0.05 g/l and chromic acid in a concentration of 0.005-0.2 g/l. 12. A method according to claim 2, characterized by using as said cerium compound cerium perhalogenate, or cerium nitrate. 13. A method according to claim 2, characterized by performing said oxidation in the presence of perhalogen acid in such a concentration that the pH value is below 2. 14. A method according to claim 2, characterized by performing said oxidation with perhalogen acid having a molarity within the range of 0.01-8M. 15. A method according to claim 2, characterized by using as said oxidation agent an acidic aqueous solution of Ce.sup.4+ and chromic acid as well as ozone in a saturated solution and dispersed form. 16. A method according to claim 2, characterized by using as said oxidation agent a two-phase ozone gas-aqueous mixture where ozone in gaseous form has been dispersed in an acidic aqueous solution of Ce.sup.4+ and chromic acid. 17. A method according to claim 2, characterized by performing the oxidation and dissolution in one and the same step. 18. A method according to claim 2, characterized by performing the oxidation and dissolution at a temperature below about 60.degree. C. 19. A method according to claim 2, characterized by performing the oxidation with an external addition of chromic acid to the oxidation solution. 20. A method according to claim 2, characterized by performing said oxidation in the presence of Ce.sup.4+ in a concentration of 0.5-10 g/l, ozone in a concentration of 0.001-0.05 g/l and chromic acid in a concentration of 0.005-0.2 g/l. 21. A method according to claim 1 wherein said perhalogen acid is perchloric acid. 22. A method according to claim 3 wherein said cerium perhalogenate is cerium perchlorate. 23. A method according to claim 1 wherein said perhalogen acid is provided in such a concentration that the pH value is below 1. 24. A method according to claim 1 wherein said perhalogen acid is provided in such a concentration that the pH value is within the range of 0.5-1. 25. A method according to claim 1, characterized by performing said oxidation with perhalogen acid having a molarity within the range of 0.1-2M. 26. A method according to claim 9, characterized by performing the oxidation and dissolution at a temperature within the range of 20.degree.-30.degree. C. 27. A method according to claim 9, characterized by performing the oxidation and dissolution at a temperature within the range of 20.degree.-25.degree. C. 28. A method according to claim 2, characterized by using as said cerium compound cerium perchlorate. 29. A method according to claim 2, wherein perhalogen acid is provided in such a concentration that the pH value is below 1. 30. A method according to claim 2, wherein said perhalogen acid is provided in such a concentration that the pH value is within the range of 0.5-1. 31. A method according to claim 2, characterized by performing said oxidation with perhalogen acid having a molarity within the range of 0.1-2M. 32. A method according to claim 2, characterized by performing the oxidation and dissolution at a temperature within the range of 20.degree.-30.degree. C. 33. A method according to claim 2, characterized by performing the oxidation and dissolution at a temperature within the range of 20.degree.-25.degree. C.
	summary
048805599	claims	1. A composition consisting of (A) water; (B) about 0.5 to about 3% by weight of a ceric acid selected from the group consisting of tetrasulfato ceric acid, hexasulfamato ceric acid, hexaperchlorato ceric acid, and mixtures thereof; and (C) and about 1 to about 5% by weight of an inorganic acid, where said inorganic acid is sulfuric acid when said ceric acid is tetrasulfato ceric acid, sulfamic acid when said ceric acid is hexasulfamato ceric acid, perchloric acid when said ceric acid is hexaperchlorato ceric acid, and a corresponding mixture selected from the group consisting of sulfuric acid, sulfamic acid, and perchloric acid when said ceric acid is a mixture selected from the group consisting of tetrasulfato ceric acid, hexasulfamato ceric acid, and hexaperchlorato ceric acid. 2. A composition according to claim 1 wherein said ceric acid is tetrasulfato ceric acid. 3. A composition according to claim 1 which includes ozone.
051924927	abstract	Method and apparatus for maintaining a water level which immerses heat exchanger tubes, containing radioactive emitting material, within an inner shell of a steam generator while permitting space between the inner shell and a coaxial outer shell to be free of water during operations performed by workmen in such space after the apparatus is installed thereby reducing exposure of the workmen to harmful radiation. Seal support segments are installed around the inner shell at the lower end of the space and in engagement with the inner and outer shells. A pair of inflatable tubes are placed end-to-end on the support segments so as to encircle the inner shell. Seal retention segments which, together, form a ring around the inner shell are placed on the inflatable tubes and the latter tubes are inflated to form a water tight seal between the shells. The water level in the shells can be lowered to a level below the inflatable tubes during installation of the components and the water level within the inner shell can be raised so as to immerse the radiation emitting tubes after inflation of the inflatable tubes, but preferably, the radiation emitting tubes are maintained immersed in water until the components are installed and the inflation of the inflatable tubes, and water in the space is then pumped out.
	description	The information setting forth the placement of fuel bundles, each of which has various attributes, in a nuclear reactor core is referred to as the loading map. In conventional core design, creating the loading map is an experienced based, trial and error, iterative process. The core designer generally receives plant specific critical to quality factors such as plant cycle energy requirements, thermal and operational limits, shut down margins, etc. The core designer will also have information on the layout of the reactor core; namely, an indication of the how the nuclear fuel bundles are positioned within the core. Some of the critical to quality factors may even concern the layout. For example, the core designer may receive input requiring the positioning of certain fuel bundles within the layout. Given this information, the core designer then makes a guess, based on experience and various rules of thumb he may have developed over time, on the initial positioning of fuel bundles in the reactor core. Specifically, the core designer guesses how many fresh fuel bundles to place in the core, and what types of fresh fuel bundles to use. A fresh fuel bundle is a fuel bundle that has not been exposed. Fuel bundles of the same type have substantially the same attributes. The attributes include but are not limited to: uranium loading, average enrichment, gadolinia loading, number of axial zones, product line, and thermal-mechanical characteristics of the fuel bundles. Different types of fresh fuel bundles have one or more different attributes. In deciding how many fresh fuel bundles to use, the core designer is also deciding how many of the fuel bundles currently in the core to reuse. Reusing the fuel bundles currently present in the core can mean leaving a fuel bundle in its existing location, or moving the fuel bundle to a different location in the core. As part of the core design, the core designer also determines other operational parameters of the reactor core such as control blade positions, core flow, etc. Having specified these operational control parameters, a Nuclear Regulatory Commission (NRC) licensed simulation program is then run on the initial core design. Based on the results of the simulation, the core designer utilizes experience and rules of thumb to fix perceived problems in the design and, in general, improve the design; particularly with respect to the critical to quality factors. These changes may include changing the loading map. The process repeats until the core designer is satisfied with the design. The present invention provides a method and apparatus for using nuclear fuel discarded to one or more fuel pools in a loading map for a new cycle of a nuclear reactor. In one exemplary embodiment, a graphical user interface under the control of a computer processor provides a user with the capability to selectively populate a loading map with fuel bundles residing in at least one fuel pool. For example, the computer processor may include a memory storing at least one fuel pool database. The fuel pool database includes a list of at least a portion of the fuel bundles residing in the fuel pool, and the user may select which of these fuel bundles to use in creating the loading map. In an exemplary embodiment, the fuel pool database indicates one or more attributes for the listed fuel bundles, and the graphical user interface that includes one or more fuel pool database management tools for aiding in the selection process. For example the tools may provide for filtering and/or sorting the fuel pool database. In a further exemplary embodiment, the a graphical user interface is controlled to further allow the user to selectively populate the loading map with different types of fresh fuel bundles. For example, the computer processor may include a memory storing at least one fresh bundle type database. The fresh bundle type database includes a list of fresh bundle types, and the user may select which of these fuel bundles to use in creating the loading map. In an exemplary embodiment, the fresh bundle type database indicates one or more attributes for the listed fuel bundles types, and the graphical user interface that includes one or more fresh bundle type database management tools for aiding in the selection process. For example the tools may provide for filtering and/or sorting the fresh bundle type database. A reactor may then be operated using a loading map that contains fuel bundles recovered from one or more fuel pools. FIG. 1 illustrates an embodiment of an architecture according to the present invention. As shown, a server 10 includes a graphical user interface 12 connected to a processor 14. The processor 14 is connected to a memory 16. The server 10 is directly accessible by a user input device 18 (e.g., a display, keyboard and mouse). The server 10 is also accessible by computers 22 and 26 over an intranet 20 and the Internet 24, respectively. The operation of the architecture shown in FIG. 1 will be discussed in detail below. Creating a Template A user via input 18, computer 26 or computer 22 accesses the server 10 over the graphical user interface 12, and runs a loading map editor program stored in memory 16 according to an exemplary embodiment of the present invention. The loading map editor provides for creating and editing a graphical representation of a nuclear reactor core referred to as a template. However, another form of conveying this information, such as a text file, may also be thought of as the template. FIG. 2 illustrates a quarter-core screen shot of a partially completed template designed according to the methodologies of the present invention using the loading map editor of the present invention. When the loading map editor is initially run, the user has the option via a file menu 30 to access a previously created template or to begin a new template. Assuming the user begins a new template, the loading map editor request the user to identify the nuclear reactor for which the template is being created. The loading map editor then retrieves the geometry of the identified nuclear reactor from a relational database containing nuclear reactor plant characteristics stored in the memory 18. The loading map editor then displays a blank colorless fuel bundle field 36 of the appropriate size based on the retrieved plant characteristics with the rows and columns numbered (such as with the fuel bundle position Row 6, Column 3 in FIG. 2). Within the fuel bundle field 36, the user may then, for example, using a mouse associated with the input 18, computer 26 and computer 22 click on the fuel bundle positions 38 in the array of possible fuel bundle positions to identify the type (fresh, reinsert, or locked) and grouping of the actual fuel bundle in that position. In the context of a template, a bundle group consists of 1, 2, 4, or 8 bundles and an associated symmetry pairing of bundles within the group which may be performed either mirror or rotationally symmetric. As shown on the right side of FIG. 2, the loading map editor provides several tools for performing this assignment task. Specifically, the tools include the headings Load Type 40, Bundle Grouping 50 and Numbering Mode 60. Under the Load Type 40 tool heading, the loading map editor includes a Fresh radio button 42, a Reinsert radio button 44 and a Locked radio button 46. The Fresh, Reinsert and Locked radio buttons 42, 44 and 46 correspond to fresh, reinsert and locked fuel bundle categories. The user, for example, clicks on the desired radio button to choose the desired category and then clicks on the fuel bundle position 38 in the fuel bundle field 36 to assign that category to the fuel bundle position 38. The fresh fuel bundle category indicates to insert fuel bundles that have not been exposed. The loading map editor then displays “F” and a number “N” at the bottom of the fuel bundle position 38. The “F” indicates the fresh fuel bundle category, and the number “N” indicates the Nth fresh bundle type 38. As will be appreciated, the loading map editor maintains a count of the number of fuel bundle types assigned to the core. Multiple bundle positions can be assigned the same bundle type by specifying the same “F” and “N” value for each position. The locked fuel bundle category indicates that a fuel bundle currently occupying an associated fuel bundle position in an actual nuclear reactor core is to remain in that position in creating a new nuclear reactor core loading map. The loading map editor displays “L” and a number “N” in the fuel bundle position 38 when the locked fuel bundle category is assigned. The “L” indicates the locked fuel bundle category, and the number “N” indicates the Nth locked bundle group. The reinsert fuel bundle category indicates to insert a fuel bundle that has been exposed. The loading map editor displays only a number “N” in the fuel bundle position 38 when the reinsert fuel bundle category is assigned. The number indicates a priority of the fuel bundle position 38. The number and the priority indicated by the number will be described in detail below with respect to the Numbering Mode 60 heading. In an exemplary embodiment, the loading map editor displays the fuel bundle positions 38 in a color associated with the assigned category. For example, fresh are displayed in blue, locked are displayed in yellow, and reinserted are displayed in violet. Under the Bundle Grouping 50 heading, the loading map editor includes a “1” radio button, a “2” radio button, a “4” radio button, and an “8” radio button. When the “1” radio button is selected by the user, for example, by clicking on the “1” radio button, the category assigned by the user to a fuel bundle position 38 is associated only with the fuel bundle position 38 chosen. Selecting the “2” radio button and assigning a category to a fuel bundle position 38 causes the category to be assigned to the selected fuel bundle position as well as the fuel bundle position 180 degrees symmetric to the selected fuel bundle position. Selecting the “4” radio button causes the loading map editor to request the user to chose between rotational and mirror symmetry. Rotational symmetry is an image property indicating there is a center point around which the object is turned a certain number of degrees and the object still looks the same (i.e., it matches itself a number of times while it is being rotated,). Mirror symmetry (or line symmetry) indicates a correspondence in size, shape, and relative position of parts on opposite sides of a dividing line. If the user assigns a category to a fuel bundle position when rotational symmetry is chosen, this causes the category to be assigned to the selected fuel bundle position as well as the fuel bundle position 38 in each of the other quadrants rotationally symmetric to the selected fuel bundle position. If the user assigns a category to a fuel bundle position when mirror symmetry is chosen, this causes the category to be assigned to the selected fuel bundle position as well as the fuel bundle position in each of the other quadrants symmetric to the selected fuel bundle position. Selecting the “8” radio button causes the loading map editor to consider the total fuel bundle field 36 as octant symmetric—eight symmetric pie pieces. Assigning a category to a fuel bundle position when the “8” radio button is selected causes the category to be assigned to the selected fuel bundle position 38 as well as the fuel bundle positions 38 in each of the other eight pie pieces symmetric to the selected fuel bundle position 38. Under the Numbering Mode 60 heading, the loading map editor includes an Automatic radio button 62 and a Manual radio button 64. Choosing between an automatic numbering mode by selecting the Automatic radio button 62 and a manual numbering mode by selecting the Manual radio button 64 is only permitted when the Reinsert radio button 44 or Fresh radio button 42 has been selected. The numbering mode in general is inapplicable when the Locked radio button 46 is selected. When the Automatic radio button 62 is selected, the loading map editor, which maintains a count of the number of fuel bundle positions 38 assigned the reinsert fuel bundle category, assigns the count plus one to the next fuel bundle position 38 assigned the reinsert fuel bundle category. The assigned number is displayed at the bottom of the fuel bundle position 38. Likewise, the loading map editor maintains a count of the fresh bundle types. When a fuel bundle position 38 is assigned the fresh bundle category the count plus one, referred to above as N, is assigned to that position. “F” and the value of N are displayed at the bottom of the fresh fuel bundle position. When the Manual radio button 64 is selected, the loading map editor maintains the count of the number of fuel bundle positions 38 assigned the reinsert fuel bundle category, but does not assign numbers to the fuel bundle positions 38. Instead, the user may position a cursor in the fuel bundle position 38 and enter the number manually. As alluded to above, the assigned numbers represent assigned priorities. The priorities indicate an order for loading exposed fuel bundles based on an attribute of the exposed fuel bundles. The attributes include, but are not limited to, K infinity (which is a well-known measure of the energy content of the fuel bundle, exposure of the bundle (which is accumulated mega-watt days per metric ton of uranium in the bundle), residence time of the bundle (which is how long the bundle has been resident in the nuclear reactor core), etc. In one exemplary embodiment, the shade of the color associated with the reinserted fuel bundle positions varies (lighter or darker) in association with the assigned priority. The loading map editor according to the present invention also provides several viewing options via a view menu 34 and a zoom slide button 70. Adjusting the zoom slide button 70 by clicking and dragging the zoom slide button 70 to the left and the right decreases and increases the size of the displayed fuel bundle field 36. Under the view menu 34, the user has the option to view a single quadrant of the template, or a full core view of the template. Additionally, the user can control whether certain template attributes are displayed. Specifically, the view menu 34 includes the options of displaying the following in the loading template: control blades, bundle coordinates, core coordinates, etc. Having created the loading template, the user may save the template, or even a partially created template, to the memory 18 by selecting either the “Save” or “Save As” option in the file menu 30. As discussed above, instead of creating a new template, a previously created template may be viewed and, optionally, edited. Using the file menu 30, the user selects an “open” option. The loading map editor then displays the accessible templates stored in the memory 18 or a directory of memory 18. The user then selects an accessible template, for example, by clicking on one of the accessible templates. The loading map editor will then display the chosen template. The user may then edit the chosen template. For example, after selecting a fuel bundle position 38 the user may select under the edit menu to “clear” the category assigned to the fuel bundle position 38. Besides the category assigned to this fuel bundle position 38, the loading map editor also clears the category assigned to associated fuel bundle positions 38. Associated fuel bundle positions 38 are those fuel bundle positions 38 that were assigned the fuel bundle category along with the fuel bundle position 38 selected for clearing because of the bundle grouping chosen when the category was assigned to the fuel bundle position 38 chosen for clearing. When fuel bundle positions 38 assigned the fresh or reinserted category are cleared, the loading map editor adjusts the numbering associated with that category. In the case of the fresh bundle category, this is a conditional action based on whether other bundle positions have been assigned the same fresh bundle type. Specifically, the loading map editor performs a cascade operation such that fuel bundle positions assigned the same category and having higher numbers are renumbered in sequence beginning from the lowest number of a deleted fuel bundle position. For example, if reinsert bundle positions numbered 44, 43 and 42 were cleared, then reinsert bundle position having number 45 would be renumbered 42, reinsert bundle position having number 46 would be renumbered 43, etc. The loading map editor also changes the total count of fuel bundle positions assigned the category being cleared. When unassigned bundle positions are created through editing, the user may then newly assign categories to the unassigned bundle positions in the same manner and using the same tools to create a template as described above. In so doing, the user may decide to manually assign, for example, an existing priority to a newly assigned reinsert fuel bundle position. In this instance, the reinsert fuel bundle position already having this number and each reinsert fuel bundle position having a higher number are incremented by one. As a further alternative, the user may want to adapt an existing template for one reactor to another reactor of the same size and physical bundle configuration. To do this, the user may use the “save as” feature in the file menu 30 to create a duplicate of the loading template. Subsequent changes to the bundle field will then apply to the copied template. In addition to creating a template from ‘scratch’ or editing an existing template, the user may have the loading map editor derive a template from a previously loaded core. In the loading map editor, using the file menu 30, the user selects an “auto-generate template” option. The loading map editor then displays a list of the accessible fuel cycles stored in the memory 18. Each fuel cycle corresponds to an actual loading map for a fuel cycle of a nuclear reactor. As will be appreciated, the memory 18 may store loading maps for cycles of different nuclear reactors. Accordingly, the list of cycles displayed by the loading map editor identifies both the nuclear reactor and the cycle. From the list the user selects the cycle (hereinafter “the selected cycle”) that the template will be derived from. The loading map editor then accesses the loading map for the selected cycle. The user is then presented with a dialog box for entering input parameters of the derivation process. The input parameters include: a primary attribute (e.g., exposure, K infinity, etc.) for deriving the template, a tolerance level (discussed in detail below), group list members (8, 4, or 2 bundle groupings), bundle symmetry for groups of 4, and a maximum number of assignments to each group list member. For example the user may enter K infinity as the primary attribute, and a tolerance level of 0.2 (which, as described in detail below, is used for forming bundle groups). The user may further enter that groups of 8 and 4 are permitted, the groups of 4 should have mirror symmetry and that a maximum of 14 groups of 4 are permitted. In an exemplary embodiment, the loading map editor provides the user with a drop-down menu. The user selects list members desired for the template from the options given in the drop-down menu. These options include: groups of 8, 4 and 2; groups of 8 and 4; groups of 8 (which forces groups of 4 on the minor axis of the reactor core template); and groups of 4 and 2. In selecting the maximum number of assignments for each group, the user enters this data in the order of the smallest to the largest group size. However, the maximum number of assignments for the largest groups is not entered by the user, as this value is automatically determined based on the maximum number of assignments for the smaller groups. Once the user enters the input parameters, the loading map editor will begin generating a template. First the loading map editor asks the user if locked bundle positions are permitted, if so, then the loading map editor requests the user to identify the cycle previous to the selected cycle in the same manner that the selected cycle was identified. The loading map editor then compares the loading map for the selected cycle with the loading map for the previous cycle of the identified nuclear reactor. Specifically, for each bundle position in the reactor, the loading map editor determines if loading maps for the selected and previous cycles have a bundle with the same serial number in the same bundle position. If so, the bundle position is assigned the locked fuel bundle category in the loading template. After the locked fuel bundle positions are identified, the loading map editor identifies the fresh fuel bundle positions. Specifically, for each bundle position not already identified as a locked bundle position, the loading map editor determines from the characteristics of the selected loading map if the fuel bundle in that bundle position is a fresh fuel bundle. For each identified fresh fuel bundle, the loading map editor also determines the type of fresh fuel bundle from the characteristics of the selected loading map. The loading map editor then assigns the fresh fuel category to the associated fuel bundle position in the template and assigns a type count number N to the fuel bundle position. For each type of fresh fuel bundle located in the selected loading map, the loading map editor assigns a count value to that type. This count value is then assigned to the bundle position along with the fresh fuel bundle category assignment so that fresh fuel bundle positions that should have the same type of fresh fuel bundle are identified by the same value ‘N’ in the loading template. Next, the loading map editor determines whether the identified fresh bundle category positions form any bundle groups. As discussed above, the user identifies the bundle group members permitted in the template. The bundle group members form a group members list. For each bundle position assigned the fresh fuel bundle category, the loading map editor first determines if the bundle position (hereinafter the “current bundle position”) has already been assigned to a group. If so, then the loading map editor proceeds to the next bundle position. If not, then the loading map editor selects the largest group from the group member list and identifies each of the bundle positions that form such a group with the current bundle position. If each of the bundles positions forming the group has been assigned the fresh bundle category and are of the same type as the current bundle position, then the loading map editor records the group of bundle positions as a group. If each of the bundles positions forming the group has not been assigned the fresh bundle category or one of the bundles is not the same type as the current bundle position, then the loading map editor performs the above-described process for the next largest bundle group in the group member list. This process keeps repeating until a group is formed or there are no more groups in the group member list to test. If the members of the group member list have been tested, and no group has been formed, then the current bundle position is recorded as not belonging to a group. Next, the loading map editor identifies the reinserted fuel bundle positions. The bundle positions of the template not assigned to the locked or fresh fuel bundle categories are assigned the reinserted fuel bundle category. Then, the loading map editor determines whether the reinserted bundle category positions form any bundle groups. For each bundle position assigned the reinserted fuel bundle category, the loading map editor first determines if the bundle position (hereinafter the “current bundle position”) has already been assigned to a group. If so, then the loading map editor proceeds to the next bundle position. If not, then the loading map editor selects the largest group from the group member list and identifies each of the bundle positions that form the group with the current bundle position. If each of the bundles positions forming the group has not been assigned the reinserted bundle category, then the loading map editor determines if the next largest group in the group member list includes all reinserted fuel bundle positions. If no group from the group member list results in a group of reinserted fuel bundles, then the loading map editor records the current fuel bundle position as not belonging to a group. Once a group has been formed, the loading map editor calculates the average attribute value for the group. As discussed above, the user identified a primary attribute to use in deriving the template. Here, the loading map editor uses that attribute value for each fuel bundle in the selected loading map forming the associated group in the template to calculate the average attribute value. The loading map editor then determines if the attribute value for each fuel bundle in the group is with the tolerance level from the average attribute. Again, here, the tolerance level was a user input design parameter as discussed above. If the attribute value for each fuel bundle in the group is within the tolerance level of the average attribute value, then the loading map editor records the associated fuel bundle positions in the template as belonging to a group. Otherwise, the loading map editor performs the above-described process for the next largest bundle group in the group member list. This process keeps repeating until a group is formed or there are no more groups in the group member list to test. If the members of the group member list have been tested, and no group has been formed, then the current bundle position is recorded as not belonging to a group. The loading map editor then determines if the user specified maximum for a group in the group member list has been violated. If so the editor performs a group recombination and ranking process. For example, if the number of groups of 2 exceeds the user specified maximum the editor does the following: For each group of 2, the loading map editor determines if another group of 2 forms a group of 4 meeting the symmetry requirements entered by the user. The loading map editor then determines the average attribute value and standard deviation for each newly formed potential group of 4 and ranks the potential groups of 4 based on minimum standard deviation. Next, the highest ranked groups (i.e., those with the lowest standard deviation) are assigned to the groups of 4 until the groups of 2 list does not exceed the maximum number allowed based on the user input. Those potential groups of 4 not assigned remain as groups of two. Next, the same process is performed to combine groups of 4 into groups of 8 assuming the user input parameters permit groups of 8 and the user specified maximum for groups of 4 has been violated. As a final step, the reinserted fuel bundles are assigned a priority number that, as described above, appears in the template. The fuel bundles positions are ranked based on (1) the attribute value for the fuel bundle in the associated position in the loading map if the fuel bundle position does not form part of a group; or (2) by the average attribute value of the group if fuel bundle position does form part of a group. A priority number is then assigned by this ranking with the fuel bundles having the same average attribute assigned the same priority number. This completes the template derivation process, the resulting template is then displayed in the loading map editor allowing the user to save the resulting template for future use. Using the present invention as described above, a core designer may capture his experience and rules of thumb associated with the initial design of a loading map. Furthermore, this knowledge may then be used by others to improve or adapt templates to existing core designs. Creating Loading Map The loading map editor according to the present invention includes additional functionality that allows the user to generate a loading map from the loading template. In addition, the loading map editor provides increased flexibility in creating the loading map by allowing the user the option of reloading fuel bundles currently residing in one or more fuel pools. After accessing, creating and/or editing a reactor core template using the loading map editor as discussed above, the user may then create a loading map using the template. From the file menu 30, the user chooses a “load” option. The loading map editor then displays a loading screen that includes a template access window, template information window, reload window and a load fresh window. The template access window provides a user with a drop down menu for selecting a loading template stored in the memory 18. The template information window displays summary information for the selected loading template. The summary information includes, but is not limited to, the number of fresh bundle types, the number of reinserted fuel bundle positions and the number of locked bundle positions in the loading template. The summary information may also indicate the number of fresh bundle types and number of reinserted bundles currently added in creating the loading map. FIG. 3 illustrates an exemplary embodiment of a reload window displayed by the loading map editor. The window is divided into two parts: a filtered fuel pool table 100 and a reloading pool 200. The filtered fuel pool table 100 lists (1) the exposed fuel bundles currently in the nuclear reactor under consideration, except for those fuel bundles in locked fuel bundle positions 38, and (2) the fuel bundles in one or more fuel pools for this and other nuclear reactors. As is well-known, exposed fuel bundles removed from a nuclear reactor are stored in what is known as a fuel pool. Fuel bundles from two or more nuclear reactor cores located at a same site may be stored in the same fuel pool. As shown in FIG. 3, the filtered fuel pool table 100 lists each exposed fuel bundle by its serial number and bundle name. Each fuel bundle is assigned a unique serial number, used to assure traceability of the bundle from a quality assurance perspective. The bundle name is a character string identifier used to identify the fuel bundle product line as well as nuclear characteristics, such as uranium and gadolinia loading. The filtered fuel pool table 100 also lists one or more attributes of each exposed fuel bundle listed. These attributes may include K infinity, exposure, and the last fuel cycle number for which the bundle was resident in the core. Additional attributes for an exposed fuel bundle may include: 1) bundle product line, 2) initial uranium loading, 3) initial gadolinium loading, 4) number of axial zones, 5) historical fuel cycle numbers previous to the most recent for which the bundle was resident in the core, 6) the corresponding reactor in which the fuel bundle was resident for each of the historical fuel cycles, 7) accumulated residence time, and 8) fuel bundle pedigree, a parameter that reflects the usability of the bundle for continued reactor operation. The fuel bundle pedigree is determined from a number of factors the foremost being an inspection of the fuel, either visually or by some other non-destructive test procedure, which is designed to detect a current failed fuel bundle or the vulnerability of the bundle to future failure. Failure mechanisms include such items as corrosion, debris impact, and mechanical bowing of the fuel bundle. Another factor affecting pedigree is possible reconstitution of a fuel bundle, which is a repair process involving the replacement of damaged fuel rods with replacement rods that may be a uranium containing fuel rod or alternatively, a non-uranium containing rod (e.g. stainless steel), henceforth referred to as a ‘phantom’ rod. A pedigree attribute might be ‘RU’ and ‘RP’ for reconstituted with uranium and phantom rods, respectively, and ‘DC’, ‘DD’ and ‘DB’ for damaged by corrosion, debris, and bow, respectively. A ‘blank’ pedigree attribute would designate a bundle that was undamaged and useable. All attributes with the exception of bundle pedigree are populated within the database via a direct relationship with the historical fuel cycles. The fuel pedigree attribute for non ‘blank’ designations are entered into the database via a separate process that is tied to fuel inspection and reconstitution services. In this process, the fuel bundles in a fuel pool are inspected and the pedigrees of the fuel bundles ascertained from the inspection. Then, a bundle status program is accessed. The bundle status program provides a GUI menu for ‘Fuel Inspection’, which is accessed by the user. The user clicks on the pulldown menu ‘Add’ from the ‘Fuel Inspection’ menu, and is presented with a pop-up for typing in the bundle serial number and the pedigree designation, such as ‘DD’ corresponding to a debris damaged bundle. The pedigree data entered in this manner is associated with the fuel pool database. The user may also click a ‘Census’ option from the ‘Fuel Inspection’ menu. Selecting this option will perform a query of the fuel pool database and present the user with a list of bundle serial numbers and corresponding attribute data, as described previously, for those bundles containing a non-null pedigree designation. The user may elect to change existing pedigree information by selecting the bundle entry, right-clicking a ‘Modify’ option, which activates the pedigree attribute field, and entering the modified pedigree information. For example, a bundle that was previously damaged may have been reconstituted. Alternatively, the user may right-click a ‘Delete’ option, which has the effect of reverting the bundle pedigree status back to null. The reloading fuel pool table 200 provides the same information for each fuel bundle as provided by the filtered fuel pool table 100. Additionally, the reloading fuel pool table 200 indicates the priority number 202 for each fuel bundle group as set forth in the loading template. As discussed above with respect to the loading template, reinserted fuel bundles may be assigned as a group of 1, 2, 4 or 8 bundles. Accordingly, FIG. 3 shows that the highest priority reinserted fuel bundle position(s) are a group of four fuel bundles, and the next highest priority reinserted fuel bundle(s) are a group of eight fuel bundles. The reloading fuel pool table 200 is populated by moving fuel bundles from the filtered fuel pool table 100 into the reloading fuel pool table 200. As further shown in FIG. 3, the reload window further includes a set of tools 120 for aiding the user in selecting and moving fuel bundles from the filtered fuel pool table 100 to the reload fuel pool table 200. The set of tools 120 include, but are not limited to, a filter tool 130, a move right tool 160, a move left tool 170 and a delete tool 180. A user selects the filter tool 130 by, for example, clicking on the filter tool 130. This opens a filter window as shown in FIG. 4. As shown, the filter window lists the same attributes listed in the filtered fuel pool table 100, and allows the user to indicate to filter based on the attribute by clicking in the selection box 132 associated with the attribute. When an attribute has been selected, a check is displayed in the associated selection box 132. The user may also unselect an attribute by again clicking in the associated selection box. In this case, the check mark will be removed. For each attribute, the filter window may display one or more filter characteristics associated with the attribute. For example, for the filter characteristics of the K infinity attribute, the user may select a filter operator 134 of greater than, less than, or equal to and enter in a filter amount 136 associated with the filter operator 134. As shown in FIG. 4, a user has selected to filter based on K infinity, chosen the greater than filter operator, and entered the filter amount of 1.2. As a result, the loading map editor will filter the fuel bundles in the filtered fuel pool table 100 to display only those fuel bundles having a K infinity greater than 1.2. As another example, the exposure attribute also has an associated filter operator and filter amount. As will be appreciated, the filter characteristics of an attribute will depend on the attribute. Also, as will be appreciated, other methodologies for indicating the filter characteristics may be possible. For example, for the cycle attribute, the filter window provides a drop down menu for selecting the cycle number. FIG. 4 shows cycles 2 and 4 selected from the drop down menu for the cycle attribute. As a result, the loading map editor filters the filtered fuel pool table 100 to display only those fuel bundles whose most recent residence was in cycle 2 or cycle 4. Similarly, the user may elect to filter bundles based on their pedigree, product line, etc. Once the attributes for filtering on have been selected and the filter characteristics have been entered, the user causes the loading map editor to filter the filtered fuel pool table based on this information by clicking on the OK selection box. Alternatively, the user may cancel the filter operation by clicking on the CANCEL selection box. The filtered fuel pool table 100 also provides a filtering mechanism for filtering the fuel bundles listed therein. A user may sort the filtered fuel pool table 100 in ascending or descending order of an attribute by clicking on the attribute heading in the filtered fuel pool table 100. Once the user clicks on the attribute, the loading map editor displays a popup menu with the options “Sort Ascending” and “Sort Descending”. The filtered fuel pool table 100 is then filtered in ascending or descending order of the attribute based on the option clicked on by the user. To move fuel bundles from the filtered fuel pool table 100 to the reload fuel pool table 200, the user selects the fuel bundles for transfer by clicking and dragging to highlight one or more of the fuel bundles in the filtered fuel pool table 100. Then the user clicks on the move right tool 160. This causes the selected fuel bundles to populate the highest priority unpopulated fuel bundle positions in the reload fuel pool table 200. Alternatively, a user clicks and drags the highlighted fuel bundles into one of the priority sections of the reloading fuel pool table 200. Fuel bundles may also be moved from the reload fuel pool table 200 back into the filtered fuel pool table 100 by selecting fuel bundles in the reload fuel pool table 200 and clicking on the move left tool 170. Alternatively, the selected fuel bundles may be clicked and dragged back to the filtered fuel pool table 100. The delete tool 180 provides the user with the function of deleting fuel bundles from either the filtered or reload fuel pool tables 100 and 200. The user may select one or more fuel bundles in one of the tables, and click the delete tool to delete the selected fuel bundles from the table. Next, the loading of fresh bundles into the template will be described. FIG. 5 illustrates an exemplary embodiment of a load fresh window displayed by the loading map editor. The window is divided into two parts: a fresh bundle types table 300 and a fresh bundle pool table 400. The fresh bundle types table 300 lists the available fresh fuel bundle types. As shown in FIG. 5, the fresh bundle types table 300 lists each fresh fuel bundle type by its bundle name. The bundle name is a character string identifier used to identify the fuel bundle product line as well as nuclear characteristics, such as uranium and gadolinia loading. The fresh fuel bundle types table 300 also lists one or more attributes of each fresh fuel bundle type listed. These attributes may include K infinity, fuel bundle product line, average uranium-235 enrichment, percent (as a function of total fuel weight) of gadolinia burnable poison contained in the fuel bundle, number of gadolinia-containing fuel rods, and number of axial zones, where an axial zone is defined by a cross-sectional slice of the bundle that is homogeneous along the axial direction. Other attributes of the fresh bundle may include parameters for predicted thermal behavior, such as R-factors and local peaking, calculated for various bundle exposure values. R-factors are used as inputs to the critical power ratio (CPR) and are determined from a weighted axial integration of fuel rod powers. Local peaking is a measure of the fuel rod peak pellet and clad temperature. The fresh bundle pool table 400 provides the same information for each fuel bundle as provided by the fresh bundle types table 300. Additionally, the fresh bundle pool table 400 indicates the type number 402 for each type of fresh bundle in the loading template and then number of fresh fuel bundles of that type in the loading template. FIG. 5 shows that the first type of fresh fuel bundle position(s) are a group of four fuel bundles, and the next type of fresh fuel bundle(s) are a group of eight fuel bundles. The fresh bundle pool table 400 is populated by moving fuel bundles from the fresh bundle types table 300 into the fresh bundle pool table 400. As further shown in FIG. 5, the load fresh window includes the same filter tool 130, move right tool 160 and delete tool 180 for aiding the user in selecting and moving fuel bundles from the fresh bundle types table 300 to the fresh bundle pool table 400 as already described above. As will be appreciated, because the attributes for the fresh fuel bundles are different than the reinserted fuel bundles the filtering characteristics may also differ accordingly. The loading map editor also provides, as shown in FIG. 5, for filtering the fresh bundle types table 300 in ascending or descending order of an attribute in the same manner that the filtered fuel pool table 100 may be sorted. The selection and moving process for fresh fuel bundles does differ from the process for moving burnt fuel because the destination of the fuel must be chosen in the grouped fresh fuel bundle pool table 400 located on the right side of the fresh bundle types table 300. Namely, after a user selects the fresh bundle type from the fresh bundle types table 300, the user then selects one or more fuel bundle positions in the fresh fuel bundle pool table 400. By selecting the move right tool 160, the selected fuel bundle positions in the fresh fuel bundle pool table 400 are populated with the selected fresh bundle type. Alternatively, the user may click and drag the bundle type into the fresh fuel bundle pool table 400. Unlike with the filtered fuel pool table 100, the fresh fuel types are not removed from the fresh bundle types table 300 but are, instead, copied as fuel bundles into the fresh bundle pool table 400. Once the reinserted and fresh fuel bundle positions 38 are filled using the tools described in detail above, the user may click on a “populate” button displayed in the loading screen to have the loading map displayed. The user may then save the created loading map by using the “Save” or “Save As” options in the file menu 30. Having created the loading map, the user may then perform simulations on reactor core performance, etc. using the loading map created according to the methodologies of the present invention. By allowing the user to draw on the resources of the fuel pool(s), the present invention provides for greater flexibility in the creation of the loading map and may also reduce the overall cost in loading a nuclear reactor core. The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
	claims	1. A pattern writing method using a charged particle beam, comprising:irradiating a shot of a charged particle beam; anddeflecting the charged particle beam of the shot using a first deflector to set a beam-on state and a beam-off state for each shot and using a second deflector to form a variable-shaped beam for each shot, the first and second deflectors being arranged on an optical path of the charged particle beam, so as to write a pattern on a target object,wherein any one of the first and second deflectors controls deflection of a charged particle beam of a shot different from a shot which is controlled in deflection by another deflector in the same period, and a voltage of the second deflector reaches a target voltage for each shot before a charged particle beam for each shot reaches the second deflector. 2. The pattern writing method according to claim 1, wherein the deflecting the charged particle beam comprises causing the first and second deflectors to perform a pipeline process with respect to shots of the charged particle beam. 3. A pattern writing method using a charged particle beam, comprising:irradiating a shot of a charged particle beam;deflecting a charged particle of the beam to write a pattern on a target object;independently applying voltages to deflectors so that an original voltage applied to a deflector on an upper stage of a plurality of stages is applied to a deflector on a lower stage of the plurality of stages in accordance with movement of the charged particle, the original voltage applied to the deflector on the upper stage and the original voltage applied to the deflector on the lower stage being same in electrical polarity, by using the deflectors obtained by dividing a base deflector to cause the charged particle to obtain a predetermined amount of deflection in the plurality of stages, when deflecting the charged particle;beginning preparation for deflection of the next shot by at least another deflector when deflecting by one of the deflectors for a certain shot; andperforming control which charges an appropriate voltage as a sum of the deflectors to the charged particle irradiated, when deflecting the charged particle. 4. A charged particle beam writing apparatus, comprising:a first deflector configured to not deflect a charged particle beam to set a beam-on state and to deflect the charged particle beam to set a beam-off state;a second deflector configured to deflect the charged particle beam to shape the beam; anda third deflector configured to deflect the charged particle beam to a predetermined position on a target object,wherein at least two deflectors of the first, second, and third deflectors control deflection of charged particle beams of different shots in the same period, and a voltage of at least one of the second and third deflectors reaches a target voltage for each shot before a charged particle beam for each shot reaches the at least one of the second and third deflectors. 5. The charged particle beam writing apparatus according to claim 4, further comprising:a plurality of timing signal generating units configured to generate and to output first, second, and third timing signals to sequentially deflect charged particle beams of the same shot by the first, second, and third deflectors, respectively. 6. The charged particle beam writing apparatus according to claim 5,wherein the plurality of timing signal generating units are configured to independently generate the first, second, and third timing signals. 7. The charged particle beam writing apparatus according to claim 6, further comprising:a first voltage applying unit configured to receive the first timing signal and to apply a voltage to the first deflector on the basis of the first timing signal;a second voltage applying unit configured to receive the second timing signal and to apply a voltage to the second deflector on the basis of the second timing signal; anda third voltage applying unit configured to receive the third timing signal and to apply a voltage to the third deflector on the basis of the third timing signal. 8. The charged particle beam writing apparatus according to claim 7, further comprising:a first buffer configured to temporarily store a first deflection signal to be output to the first voltage applying unit;a second buffer configured to temporarily store a second deflection signal to be output to the second voltage applying unit; anda third buffer configured to temporarily store a third deflection signal to be output to the third voltage applying unit. 9. The charged particle beam writing apparatus according to claim 8, further comprising:a distribution unit configured to generate the first, second, and third deflection signals to distribute the first, second, and third deflection signals to the first, second, and third buffers, respectively. 10. The charged particle beam writing apparatus according to claim 4, further comprising:means for causing the first, second, and third deflectors to perform a pipeline process with respect to shots of the charged particle beam. 11. A charged particle beam writing apparatus, comprising:an irradiation unit configured to irradiate a charged particle beam;deflectors of a plurality of stages, each deflector having a deflector length shorter than a first deflector length that causes each charged particle in the charged particle beam to obtain a predetermined amount of deflection; anda voltage applying unit configured to independently apply voltages to the deflectors of the plurality of stages so that an original voltage applied to the deflector of an upper stage of the plurality of stages is applied to the deflector of a lower stage of the plurality of stages in accordance with movement of the charged particle, the original voltage applied to the deflector of the upper stage and the original voltage applied to the deflector of the lower stage being same in electrical polarity. 12. The charged particle beam writing apparatus according to claim 11, wherein the deflectors have stages separated from one another. 13. A charged particle beam writing apparatus, comprising:a first deflector configured to not deflect a charged particle beam to set a beam-on state for each shot and to deflect the charged particle beam to set a beam-off state for each shot;a second deflector configured to deflect the charged particle beam to form a variable-shaped beam for each shot; anda third deflector configured to deflect the charged particle beam to a predetermined position on a target object,wherein at least two deflectors of the first, second, and third deflectors control deflection of charged particle beams of different shots in the same period, and a voltage of at least one of the second and third deflectors reaches a target voltage for each shot before a charged particle beam for each shot reaches at least one of the second and third deflectors. 14. The pattern writing method using a charged particle beam according to claim 1, further comprising:adjusting a voltage applied to the second deflector to form the variable-shaped beam. 15. The charged particle beam writing apparatus according to claim 13, wherein a voltage applied to the second deflector is adjusted to form the variable-shaped beam.
	description	This application is a continuation of International Application No. PCT/CN2016/110396, filed on Dec. 16, 2016, which claims priority to Chinese Patent Application No. 201610517978.4, filed on Jul. 4, 2016; Chinese Patent Application No. 201620699033.4, filed on Jul. 4, 2016, the disclosures of which are hereby incorporated by reference. The present disclosure relates to an irradiation apparatus for radioactive rays, especially to a neutron therapy apparatus. A neutron therapy apparatus used in boron neutron capture therapy apparatus normally gives the irradiated object multiple angles irradiation because of need. In the past, in order to achieve this kind of multiple angles irradiation, the neutron therapy apparatus was normally fixed on some rotary apparatus which had enormous structure, and the rotation of the neutron therapy apparatus was driven by the rotation of the rotary apparatus. Obviously, the structure of the neutron therapy apparatus itself is already quite big, so it may need a rotary apparatus even bigger than the neutron therapy apparatus to drive the rotation of the neutron therapy apparatus by an external rotary apparatus, and quite large space is further needed to satisfy the rotation of the neutron therapy apparatus and the rotary apparatus at the same time. Therefore the whole apparatus is not only bulky but also with low application, and it is not benefit to the miniaturization design of the neutron therapy apparatus. The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. In order to provide a neutron therapy apparatus which give multi angles neutron beam irradiation, in one aspect of the present disclosure provides a neutron therapy apparatus includes: a beam shaping assembly including a moderator and a reflector surrounding the moderator, wherein the moderator moderates neutrons to a predetermined energy spectrum and the reflector guides deflected neutrons back to enhance the neutron intensity in the predetermined energy spectrum; a neutron generator embedded inside the beam shaping assembly, wherein the neutron generator generates neutrons after irradiated by an ion beam; at least a tube for transmitting the ion beam to the neutron generator, wherein the tube defines at least an axis; deflection magnets for changing the transmission direction of the ion beam; a collimator for concentrating neutrons; and an irradiation room for receiving a irradiated object, wherein the beam shaping assembly rotates around the axis of the tube. Implementations of this aspect may include one or more of the following features. More particularly, the neutron therapy apparatus further includes a supporting frame for holding the beam shaping assembly, the beam shaping assembly rotates around the axis of the tube and/or moves along the supporting frame. Furthermore, the tube includes a first tube portion defining a first axis and a second tube portion defining a second axis and connected with the first tube portion, the beam shaping assembly rotates around the first axis of the first tube portion or the second axis of the second tube portion. Furthermore, a first angle is formed between the first tube portion and the second tube portion, the degree of the first angle is changed to adjust the position of the beam shaping assembly relative to the irradiated object in the irradiation room. Furthermore, the supporting frame includes a first supporting part and a first track set in the first supporting part, the beam shaping assembly is retained on the first track of the supporting frame, the first track is concaved in the supporting frame so as to form a containing room connected with the irradiation room, the collimator extends into the irradiation room through the containing room. More particularly, both of the first supporting part and the first track are arranged in arc-shape, the first supporting part includes an arc-shaped external surface, the first track is concaved from the arc-shaped external surface of the first supporting part. More particularly, the tube further includes a third tube portion connected with the neutron generator, a second angle is formed between the second tube portion and the third tube portion, and the degree of the second angle is changed to adjust the position of the beam shaping assembly relative to the irradiated object in the irradiation room. The deflection magnets are fixed on the supporting frame, the deflection magnets include a first deflection magnet located between the first tube portion and the second tube portion and a second deflection magnet located between the second tube portion and the third tube portion, the ion beam in the first tube portion is transmitted into the second tube portion after the transmission direction is changed by the first deflection magnet, the ion beam in the second tube portion is transmitted into the third tube portion after the transmission direction is changed by the second deflection magnet, the ion beam in the third tube portion irradiates on the neutron generator to generate neutron beams. More particularly, the supporting frame further includes a second supporting part for supporting the second deflection magnet, the second supporting part includes a second track, the second supporting part moves in the second track while the beam shaping assembly moves in the first track. The neutron therapy apparatus further includes an accelerator, and the supporting frame further includes a third supporting part, the first deflection magnet is fixed on the third supporting part, the first tube portion is fixed between the accelerator and the first deflection magnet, the third tube portion is connected with the beam shaping assembly and the second deflection magnet, the second tube portion is connected with the first deflection magnet and the second deflection magnet. In another aspect of the present disclosure, a neutron therapy apparatus is provided to give multi angles neutron beam irradiation, the neutron therapy apparatus includes: a beam shaping assembly including a moderator and a reflector surrounding the moderator, wherein the moderator moderates neutrons to a predetermined energy spectrum and the reflector guides deflected neutrons back to enhance the neutron intensity in the predetermined energy spectrum; a neutron generator embedded inside the beam shaping assembly, wherein the neutron generator generates neutrons after irradiated by an ion beam; at least a tube for transmitting the ion beam to the neutron generator; deflection magnets for changing the transmission direction of the ion beam; a collimator for concentrating neutrons; and a supporting frame, wherein the beam shaping assembly retains on the supporting frame and moves on the supporting part. More particularly, the supporting frame includes a first supporting part for retaining the beam shaping assembly, a first track is set in the first supporting part, the first track is concaved in the supporting frame to form a containing room which is connected with the irradiation room, the collimator extends into the irradiation room through the containing room. Furthermore, both of the first supporting part and the first track are arranged in arc-shape, the first supporting part includes an arc-shaped external surface, the first track is concaved from the arc-shaped external surface of the first supporting part. More particularly, the deflection magnets are fixed on the supporting frame, the deflection magnets include a first deflection magnet and a second deflection magnet, the supporting frame includes a second supporting part having a second track for supporting the second deflection magnet, the second deflection magnet moves in the second track while the beam shaping assembly moves in the first track. More particularly, the tube includes a first tube portion defining a first axis connected to the accelerator and the first deflection magnet, a third tube portion connected to neutron generator, and a second tube portion defining a second axis connects the first tube portion and the third tube portion, the beam shaping assembly rotates around the first axis or the second axis, the ion beam in the first tube portion is transmitted into the second tube portion after the transmission direction has been changed by the first deflection magnet, the ion beam in the second tube portion is transmitted into the third tube portion after the transmission direction has been changed by the second deflection magnet, the ion beam in the third tube portion irradiates on the neutron generator to generate neutron beams. Furthermore, the supporting frame further includes a third supporting part, the first deflection magnet is fixed on the third supporting part. In another aspect of the present disclosure, a neutron therapy apparatus is provided to give multi angles neutron beam irradiation, the neutron therapy apparatus includes: a beam shaping assembly including a moderator and a reflector surrounding the moderator, wherein the moderator moderates neutrons to a predetermined energy spectrum and the reflector guides deflected neutrons back to enhance the neutron intensity in the predetermined energy spectrum; a neutron generator embedded inside the beam shaping assembly, wherein the neutron generator generates neutrons after irradiated by an ion beam; at least two tubes for transmitting the ion beam to the neutron generator; deflection magnets for changing the transmission direction of the ion beam; and a collimator for concentrating neutrons, wherein a first angle is formed between the two tubes, and the degree of the first angle is changeable. More particularly, the tubes includes a first tube portion connects to the accelerator, a third tube portion connects to the neutron generator, and a second tube portion connects the first portion and the third tube portion, the first angle is formed between the first tube portion and the second tube portion, a second angle is formed between the second tube portion and the third tube portion, at least one of the first angel and the second angel is changeable. More particularly, the neutron therapy apparatus includes a supporting frame for fixing the deflection magnets, the supporting frame includes a first supporting part with a first track for retaining the beam shaping assembly, the deflection magnets include a first deflection magnet and a second deflection magnet, the supporting frame further includes a second supporting part for supporting the second deflection magnet, the second supporting part includes a second track, the second deflection magnet moves in the second track while the beam shaping assembly moves in the first track. More particularly, the supporting frame includes a third supporting part, the first deflection magnet is fixed on the third supporting part. Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. Neutron capture therapy (NCT) has been increasingly practiced as an effective cancer curing means in recent years, and BNCT is the most common. Neutrons for NCT may be supplied by nuclear reactors or accelerators. Take AB-BNCT for example, its principal components comprise, in general, an accelerator for accelerating charged particles (such as protons and deuterons), a target, a heat removal system and a beam shaping assembly. The accelerated charged particles interact with the metal target to produce the neutrons, and suitable nuclear reactions are always determined according to such characteristics as desired neutron yield and energy, available accelerated charged particle energy and current and materialization of the metal target, among which the most discussed two are 7Li (p, n) 7Be and 9Be (p, n) 9B and both are endothermic reaction. Their energy thresholds are 1.881 MeV and 2.055 MeV respectively. Epithermal neutrons at a keV energy level are considered ideal neutron sources for BNCT. Theoretically, bombardment with lithium target using protons with energy slightly higher than the thresholds may produce neutrons relatively low in energy, so the neutrons may be used clinically without many moderations. However, Li (lithium) and Be (beryllium) and protons of threshold energy exhibit not high action cross section. In order to produce sufficient neutron fluxes, high-energy protons are usually selected to trigger the nuclear reactions. BNCT takes advantage that the boron (10B)-containing pharmaceuticals have high neutron capture cross section and produces 4He and 7Li heavy charged particles through 10B(n,α)7Li neutron capture and nuclear fission reaction. The two charged particles, with average energy at about 2.33 MeV, are of linear energy transfer (LET) and short-range characteristics. LET and range of the alpha particle are 150keV/micrometer and 8 micrometers respectively while those of the heavy charged particle 7Li are 175keV/micrometer and 5 micrometers respectively, and the total range of the two particles approximately amounts to a cell size. Therefore, radiation damage to living organisms may be restricted at the cells' level. When the boronated pharmaceuticals are gathered in the tumor cells selectively, only the tumor cells will be destroyed locally with a proper neutron source on the premise of having no major normal tissue damage. No matter BNCT neutron sources are from the nuclear reactor or the nuclear reactions between the accelerator charged particles and the target, only mixed radiation fields are produced, that is, beams comprise neutrons and photons having energies from low to high. As for BNCT in the depth of tumors, except the epithermal neutrons, the more the residual quantity of radiation ray is, the higher the proportion of nonselective dose deposition in the normal tissue is. Therefore, radiation causing unnecessary dose should be lowered down as much as possible. Besides air beam quality factors, dose is calculated using a human head tissue prosthesis in order to understand dose distribution of the neutrons in the human body. The prosthesis beam quality factors are later used as design reference to the neutron beams, which is elaborated hereinafter. The International Atomic Energy Agency (IAEA) has given five suggestions on the air beam quality factors for the clinical BNCT neutron sources. The suggestions may be used for differentiating the neutron sources and as reference for selecting neutron production pathways and designing the beam shaping assembly, and are shown as follows: Epithermal neutron flux >1×109 n/cm2s Fast neutron contamination <2×10−13 Gy-cm2/n Photon contamination <2×10−13 Gy-cm2/n Thermal to epithermal neutron flux ratio <0.05 Epithermal neutron current to flux ratio >0.7 Note: the epithermal neutron energy range is between 0.5 eV and 40 keV, the thermal neutron energy range is lower than 0.5 eV, and the fast neutron energy range is higher than 40 keV. 1. Epithermal Neutron Flux The epithermal neutron flux and the concentration of the boronated pharmaceuticals at the tumor site codetermine clinical therapy time. If the boronated pharmaceuticals at the tumor site are high enough in concentration, the epithermal neutron flux may be reduced. On the contrary, if the concentration of the boronated pharmaceuticals in the tumors is at a low level, it is required that the epithermal neutrons in the high epithermal neutron flux should provide enough doses to the tumors. The given standard on the epithermal neutron flux from IAEA is more than 109 epithermal neutrons per square centimeter per second. In this flux of neutron beams, therapy time may be approximately controlled shorter than an hour with the boronated pharmaceuticals. Thus, except that patients are well positioned and feel more comfortable in shorter therapy time, and limited residence time of the boronated pharmaceuticals in the tumors may be effectively utilized. 2. Fast Neutron Contamination Unnecessary dose on the normal tissue produced by fast neutrons are considered as contamination. The dose exhibit positive correlation to neutron energy, hence, the quantity of the fast neutrons in the neutron beams should be reduced to the greatest extent. Dose of the fast neutrons per unit epithermal neutron flux is defined as the fast neutron contamination, and according to IAEA, it is supposed to be less than 210−13Gy-cm2/n. 3. Photon Contamination (Gamma-ray Contamination) Gamma-ray long-range penetration radiation will selectively result in dose deposit of all tissues in beam paths, so that lowering the quantity of gamma-ray is further the exclusive requirement in neutron beam design. Gamma-ray dose accompanied per unit epithermal neutron flux is defined as gamma-ray contamination which is suggested being less than 210−13Gy-cm2/n according to IAEA. 4. Thermal to Epithermal Neutron Flux Ratio The thermal neutrons are so fast in rate of decay and poor in penetration that they leave most of energy in skin tissue after entering the body. Except for skin tumors like melanocytoma, the thermal neutrons serve as neutron sources of BNCT, in other cases like brain tumors, the quantity of the thermal neutrons has to be lowered. The thermal to epithermal neutron flux ratio is recommended at lower than 0.05 in accordance with IAEA. 5. Epithermal Neutron Current to Flux Ratio The epithermal neutron current to flux ratio stands for beam direction, the higher the ratio is, the better the forward direction of the neutron beams is, and the neutron beams in the better forward direction may reduce dose surrounding the normal tissue resulted from neutron scattering. In addition, treatable depth as well as positioning posture is improved. The epithermal neutron current to flux ratio is better of larger than 0.7 according to IAEA. FIG. 1 shows a neutron therapy apparatus 100 of the present application. The neutron therapy apparatus 100 includes a beam shaping assembly 10, a neutron generator 11 which is set inside the beam shaping assembly 10, at least a tube which transmits ion beam P from accelerator 200 to neutron generator 11, and deflection magnets 30 which change the transmission direction of ion beam P in the tube. The beam shaping assembly 10 includes a moderator 12 and a reflector 13 surrounding the moderator 12, the neutron generator 11 is embedded into the moderator 12 (refer to FIG. 2). The beam shaping assembly 10 further includes a beam outlet, and a collimator 40 which is fixed on an end face A where the beam outlet lays in. Referring to FIG. 3, the neutron therapy apparatus 100 further includes an irradiation room 50 for giving irradiation to irradiated object M and a supporting frame 60 for supporting the beam shaping assembly. The supporting frame 60 includes a first supporting part 61. A first track 611 is set in the first supporting part 61. For the convenience of manufacturing, both of the first supporting part 61 and the first track 611 are arc-shaped with the same circle center. In other embodiments, in order to enable the beam shaping assembly to have more irradiation positions in irradiation room 50, the first supporting part 61 and the first track 611 can further be set into other shapes, which are not specifically described herein. The beam shaping assembly 10 is retained on the first track 611 and moves in the first track 611, so that the neutron therapy apparatus can give irradiation to irradiated object M in irradiation room 50 in different angles. Referring to FIG. 4 to FIG. 6, as one embodiment, the first track 611 is set on the an arc-shaped external surface of the first supporting part 61. The irradiation room 50 is located below the first supporting part 61, the first track 611 is concaved from the arc-shaped external surface of the first supporting part 61, and forms a containing room 612 which is connected with irradiation room 50. A pair of holding protions 131 extend to the two sides of the beam shaping assembly 10 from the external surface of the reflector 13, the holding portions 131 are held by the first track 611 and move in the first track 611, the collimator 40 extends to the irradiation room 50 from the containing room 612. Without doubt, for the miniaturization design of the whole neutron therapy apparatus, holding portions are not necessary, instead, the end face A of the beam shaping assembly equipped with the collimator is coordinated with the first track 611. The end face A is retained on the first track 611 directly, and the neutron therapy apparatus 100 gives multi-angles irradiation to the irradiated object M by the movement of end face A in the first track 611. As another embodiment, the irradiation room 50 is located at one side of the first supporting part 61 instead of setting below the first supporting part 61, a holding portion extends out from the beam shaping assembly 10 and is located at one side of the beam shaping assembly 10, the holding portion is retained in the first track 611 and moves in the first track 611. The beam outlet of the beam shaping assembly 10 is facing to the irradiation room 50, so that the neutron therapy apparatus 100 can irradiate the irradiated object M (unshown in the Figures) in different angles as the beam shaping assembly 10 moves in the first track 611. The first track can further be set in a front face of the first supporting part. The holding portions extend out from the external surface of the reflector and is located at one side of the beam shaping assembly, the holding portions are held in the first track and move in the first track. There are many other emplements, for example, the beam shaping assembly is retained in the first track 611 by part of the reflector without setting holding portions, as long as the reflector is able to move in the first track and the neutron therapy apparatus is able to irradiate object M in irradiation room in different angles, which are not introduced in detail herein. The tube includes a first tube portion 21 fixed on accelerator 200, a third tube portion 22 fixed on neutron generator 11 and a second tube portion 23 connects the first tube portion 21 and the third tube portion 22. The first tube portion 21 defines a first axis I and the second tube portion 23 defines a second axis II. The deflection magnet 30 includes a first deflection magnet 31 and a second deflection magnet 32. One end of the first tube portion 21 is connected to accelerator 200, the other end is connected to the first deflection magnet 31; one end of the second tube portion 23 is connected to the first deflection magnet 31, the other end is connected to the second deflection magnet 32; one end of the third tube portion 22 is connected to the second deflection magnet 32, and the other end is connected to the beam shaping assembly 10. The beam shaping assembly 10 is able to rotate around the first axis I of the first tube portion 21 or the second axis II of the second tube portion 23, to change the irradiation angles of the beam shaping assembly 10. The transmission direction of ion beam P in the first tube portion 21 is deflected by the first deflection magnet 31 and transmitted into the second tube portion 23, after being deflected by the second deflection magnet 32, the ion beams P in the second tube portion 23 are transmitted into the third tube portion 22, the ion beams P in the third tube portion 22 are transmitted to the neutron generator 11 to generate neutron beams, the neutron beams are applied to the irradiation of neutron therapy apparatus 100. The supporting frame 60 further includes a second supporting part 62 above the first supporting part 61, the second deflection magnet 32 is retained on the second supporting part 62, a second track 621 is set in the second supporting part 62 to allow the second deflection magnet 32 to move in the second track 621 along with the beam shaping assembly 10. The concrete structure of the second track 621 can refer to that of the first track 611 mentioned foregoing, which is used for the retaining of the beam shaping assembly 10 and allows the movement of beam shaping assembly 10. The second supporting part 62 can further be set behind the first supporting part 61, as shown in FIG. 9. The beam shaping assembly 10 moves in the first track 611 according to different irradiation angles needed by the irradiated object M, when the beam shaping assembly 10 moves in the first track 611 and rotates around the first axis I, the third tube portion 22 moves along with the beam shaping assembly 10, and the second deflection magnet 32 moves in the second track 621 along with the movement of the third tube portion 22, the multi-angles irradiation of the neutron therapy apparatus 100 give to the irradiated object M in the irradiation room 50 is achieved. Without doubt, the beam shaping assembly 10 can further be set into a structure that can rotate around the second axis II of the second tube portion 23 to realize the multi-angles irradiation to the irradiated object in irradiation room 50, which is not elaborated here. As shown in FIG. 7 and FIG. 8, a first angle a1 is formed between the first tube portion 21 and the second tube portion 23, and a second angle a2 is formed between the second tube portion 23 and the third tube portion 22, the degree of both the first angle a1 and the second angle a2 can be changed. According to actual requirement, at least one of the first angle a1 and second angle a2 or both of the first angle and the second angle can be set to be changed, to reduce the limitation of the irradiation angle of beam shaping assembly 10. The neutron therapy apparatus 100 further includes a third supporting part 63 which is used for retaining the first deflection magnet 31. The third supporting part 63 can be retained on the supporting frame 60, as shown in FIG. 9, and it can further be directly fixed on the ground, as shown in FIG. 3. The following is the detailed description to the whole rotation process of the neutron therapy apparatus. Firstly, determine a irradiation direction according to the specific situations of the irradiated object. According to the determined irradiation direction, the beam shaping assembly 10 moves in the first track 611 to a position that can give irradiation to the irradiated object from such an angle, then position the third tube portion 22 after it moves to some specific place along with the beam shaping assembly 10. Secondly, determine the deflecting directions of the first deflection magnet 31 and the second deflection magnet 32 according to the position of the first tube portion 21, the third tube portion 22 and the second tube portion 23. For the position of the first tube portion 21 has been fixed, the position of the third tube portion 22 is determined by the movement of the beam shaping assembly 10. The second tube portion 23 is located between the first tube portion 21 and the third tube portion 22, the first deflection magnet 31 and the second deflection magnet 32 are fixed on each end of the second tube portion 23 respectively. Therefore the position of the second tube portion 23 can be at any position that can be acquired in the space after the positions of the first tube portion 21 and the third tube portion 22 have been determined. The deflecting directions of the first deflection magnet 31 and the second deflection magnet 32 are determined by the positions of the three tube portions, so that ion beam P can be transmitted into neutron generator 11 from accelerator 200. The ion beam P in the first tube portion 21 is transmitted into the second tube portion 23 after the transmission direction has been changed by the first deflection magnet 31. And then the ion beam P in the second tube portion 23 is transmitted into the third tube portion 22 after the transmission direction has been changed by the second deflection magnet 32. The ion beam P in the third tube portion 22 is directly irradiated to the neutron generator 11 to generate neutron beams, and the neutron beams give irradiation to the irradiated object. What should be pointed out is that, although the beam shaping assembly described above has the capability of shielding radioactive rays, extra shielding assembly can provide better shielding effect in the process of irradiation therapy for the irradiated object. Especially when the first track 611 is concaved from the external surface of the first supporting part 61 and forms a containing room 612 connects with the irradiation room 50 (refer to FIG. 5), a gap is formed between the beam shaping assembly 10, the containing room 612 and the irradiation room 50. In one aspect, such a gap will affect the aesthetics of the whole neutron therapy apparatus, in another aspect, such a gap will increase the leakage of radioactive rays in the process of irradiation. Therefore a shielding assembly 70 (70′) is necessary to cover the containing room 612 and shields the irradiation room 50 in the process of irradiation. Combined with the Figures, the specific structure of shielding assembly 70 (70′) is illustrated in the following. The shielding assembly 70 (70′) is able to move along with the movement of the beam shaping assembly 10 and shield the leakage of radioactive rays from the irradiation room 50. Referring to FIG. 10 and FIG. 11, the shielding assembly 70 includes two shielding parts 71 which can stretch out or contract along with the moving direction of the beam shaping assembly 10. The shielding parts 71 are located on two sides of the beam shaping assembly 10 respectively, one end of the shielding part 71 is connected with the supporting frame 60 and the other end is connected with the beam shaping assembly 10. Each shielding part 71 includes multi shielding portions 72 whose heads and tails are buckled on each other. A locking portion 73 is set on each end of the shielding portion 72. The locking portion 73 is able to move on the surface of the shielding portion 72 and mutually buckled on the locking portion adjoined to it. When the shielding part 71 contracts, the shielding portions 72 stack together one by one; when the shielding part 71 stretches out, the shielding portions 72 expand out one by one and buckled on each other, therefore the two adjoining shielding portions 72 are positioned. If part of the shielding part 71 stretches out, that is, as shown in FIG. 10, some shielding portions 72 are expanding out, while some others still are stacked together. In conclusion, due to the movement of the beam shaping assembly 10, the shielding portions 72 expand out or stack together. As shown in FIG. 13 and FIG. 14, when the beam shaping assembly 10 moves along the first supporting frame 61, the shielding part 71 located at one side of the beam shaping assembly 10 contracts and the shielding portions on this side gradually stack, and the shielding part 71 located at the other side of the beam shaping assembly 10 stretches out and the shielding portions on this side gradually expand out. When the shielding portions 72 stack together, the shielding part 71 far away from the irradiation room 50 is connected to the beam shaping assembly 10, and the portion of the shielding part 71 close to the irradiation room 50 is connected to the supporting frame 60. As described above, the first track 611 is set in arc-shape. In this embodiment, in order to achieve better shielding effect, every shielding portion 72 is set in arc-shape. After the shielding portions 72 stretch out one by one, the whole shielding part 71 is in arc-shape. In order to masximumly reduce the leakage of radioactive rays in the process of irradiation, the height H1 of the containing room 612 is not less than the thickness of the shielding assembly 70, the thickness of the shielding assembly 70 refers to the thickness of the multi shielding portions 72 stacked together. And the width W2 of the shielding assembly 70 is not less than the width W1 of the containing room 612. FIG. 15 shows another embodiment of shielding assembly 70′. The shielding assembly 70′ is connected to both sides of the beam shaping assembly 10 and forms the irradiation room 50 described before. The shielding assembly 70′ is an integal structure and is able to rotate around the supporting frame 61 along with the movement of the beam shaping assembly 10 (as shown in FIG. 16), and is able to shield the radioactive rays leaking from the irradiation room 50. In this embodiment, the shielding assembly 70′ is contained in the containing room 612, and the width W2′ of the shielding assembly 70′ is not less than the width W1 of the containing room 612. Without doubt, the thickness of the shielding assembly 70′ can further be set to be not more than the height H1 of the containing room 612. In one aspect, the shielding assembly 70 (70′) can shield the radioactive rays leaked from the beam shaping assembly 10, in another aspect, it covers in the gap formed between the irradiation room 50, containing room 612 and the beam shaping assembly 10, which is benefit to its aesthetics. In addition, a shielding wall (not labeled) can further be set at the outer side of the shielding assembly, which is able to move away from or close to the shielding assembly 10 and is able to support the shielding assembly. When the shielding wall moves away from the shielding assembly, the beam shaping assembly 10 rotates on the supporting frame 60 according to actual requirement, to get a proper irradiation position, and the shielding assembly moves along with the movement of the beam shaping assembly 10 and covers the irradiation room 50 and shields the radioactive rays all the time; when the beam shaping assembly 10 is located at the proper irradiation position, the shielding wall moves close to the shielding assembly and the shielding assembly is supported by the shielding assembly, the beam shaping assembly 10 irradiates to the irradiation room 50, and the shielding assembly shields the irradiation room 50. In one aspect, the setting of the shielding wall provides a supporting force for the shielding assembly, and shares part of the supporting force the supporting frame suffered; in another aspect, it shields the radioactive rays generated in the process of irradiation and increases the shielding effect. The arc-shape described herein indicates not only a certain arc-shape on a circle, but also the shapes formed by the connection of multi sections of straight lines, regular or irregular curves, which are similar to the arc-shape, all belong to the arc-shape described in the application. It should be understood that, the terms used herein such as “having”, “comprise” and “include” do not exclude the existence or addition of one or more other components or the combinations thereof. The above illustrates and describes basic principles, main features and advantages of the present disclosure. Those skilled in the art should appreciate that the above embodiments do not limit the present disclosure in any form. Technical solutions obtained by equivalent substitution or equivalent variations all fall within the scope of the present disclosure.
	summary
	claims	1. A system for intervention in an atmosphere of radioactive gas, notably tritium, where this system includes:a dynamic confinement device, including:a removable confinement barrier, able to surround an intervention zone, anda controlled air extraction device, able to keep intervention zone at a lower pressure than the exterior of this zone,and also including:a monitoring device, to monitor the radioactive gas concentration in the air of the intervention zone, anda detection and signalling device, to detect the exceedance of a predefined threshold by this concentration, and to signal the exceedance to the person or persons present in the intervention zone,in which the monitoring device includes a device for measuring the volume activity of the radioactive gas, andthe device for measuring the volume activity of the radioactive gas includes:an ionisation chamber, anda device to cause samples of the extracted air to flow in the ionisation chamber. 2. A system according to claim 1, in which the controlled air extraction device includes:a filtration device, to filter any dust in the air which is extracted from the intervention zone,an adjustment device, to adjust the flow rate of the air which is extracted, anda ventilation device. 3. A system according to claim 2, also including a device for measuring the flow rate of the air which is extracted. 4. A system according to claim 1, in which the device to cause the samples to flow in the ionisation chamber includes:a first device of the Venturi type to extract the samples, anda second device of the Venturi type to restore the extracted samples. 5. A system according to claim 4, in which the device to cause the samples to flow also includes:a turbine to increase the flow of the samples in the ionisation chamber, anda device to adjust the flow rate of the extracted samples. 6. A system according to claim 1, also including a device for measuring the air flow rate in the ionisation chamber to monitor continuously the validity of the measurement of the volume activity of the radioactive gas. 7. A system according to claim 1, in which the detection and signalling device includes means to determine the radioactive gas concentration over time.
047045396	description	DETAILED DESCRIPTION OF THE INVENTION Reference is first made to FIGS. 2 and 3 showing cart 10 providing the transportation of container 12 to the various stations illustrated in FIGS. 1A through 1H. Said cart 10 is substantially made of a framework 26, placed on a rolling platform 28 via a sliding and/or rolling support 30 therebetween, designed such as to allow a limited displacement perpendicular to the rolling direction of the platform, between framework 26 and said rolling platform 28, during the introduction of cart 10 in a loading hall for receiving a container 12. Due to this feature, the cart can travel on running paths of the railway track type, with the necessary clearances for accommodating the stresses (radius of curvature, cant of the track, etc.) as well as on running paths made and mounted with accuracy, provided in the loading hall where the cart travels. The lateral centering is provided by side guiding rails 32 located on the walls of the hall and locking means 34 are provided, designed so as to allow or suppress the side motion freedom according to whether the cart is outside or inside the hall. Container 12 is positioned on the framework 26 of the cart via a plate 36 on which it is placed (FIG. 3) and which comprises means 38, for example jacks, for adjusting the height and levelness of the upper face on the container. The positioning of container with respect to the longitudinal and transverse axes thereof is obtained by a jig 40, fixed on the top of container 12, and cooperating with reference axes 42, 42 located on the upper portion of the cart framework 26, while setting means are provided for positioning the container 12 in the cart 10. In this embodiment, said setting means are in the form of screw-nut systems 44, 44' such as threaded shafts extending inwardly from opposite sidewalls of the framework 26 are respectively placed in register with the upper 46 and lower 46' support stubs on opposite sides container 12. According to the invention, the screw-nut systems 44, 44' not only ensure the container positioning, but they also maintain it in position and resist efforts to move it even due to an earthquake. Finally a resilient bumper system 48, 48', interposed between each support stub of the container and each screw-nut system, allows accomodation of displacement due to the radial expansion of the container, caused by heating, once the container has been loaded with irradiated fuel. During translation of the cart from the penetration shaft 20 (FIG. 1C) to the station for reinserting the container plug (FIG. 1G), it is necessary to provide protection against radiations emitted by the irradiated fuels loaded in the container, said container being then without its sealing plug. This radiation protection, according to another feature of this invention, is provided by a pair of movable armored protection plates shown schematically at 50 (FIG. 4) mounted on the upper platform of the framework 26 of cart 10 in such manner that a minimal distance e is obtained between the ceiling of the loading hall H and said protection plate 50, the value of said minimal spacing being set by a known mechanical device such as jacks 54 for example. According to the invention, said armored protection plates also allow reducing the radiations from the irradiated fuel when the latter is moved through penetration shaft 20, during loading of the container (station of FIG. 1E). According to the invention, the armored protection plates are provided with manual or mechanized control means, shown schematically at 52, allowing movement of the plates towards or away from each other, so as to close them against each other or in order to load and unload the container from the cart. The armored protection plates 50 fit against each other and cover in part the upper face of container 12, a clearance between the plates and the upper face container being provided for accommodating a vertical expansion of the container, due to its heating after having received the fuel. An extra armored protection can also be provided against the radiations, shown schematically at 56, fixed either on container 12 or on the framework 26 of the cart, or integrated to said framework, in order to complete a radiation shield at the top of the container when the container plug is removed. According to another feature of the invention (FIG. 5), there is provided a support trestle 58 for the container plug 14, said trestle being disposed on the cart framework 26. Trestle 58 allows depositing the container plug on the cart once it has been removed from the container, during the period when the latter is underneath the penetration shaft 20. This feature obviates having the sealing plug suspended during the container docking and loading operations, and facilitates checking and possibly changing the plug seals. According to the invention, it is possible to provide suction means such as a sucking device 60, on support trestle 58 (FIG. 5) for avoiding any discharge or dissemination of the contamination of the plug lower face. According to the invention, all the mechanisms of the cart, of the penetration shaft and for the plug removal are designed so as to be adaptable to the various types of containers, by a simple addition of adapters, allowing compensation for the differences in dimensions thereof and the needed protection from radiation. For safety reasons, notably in the case of an incidental shutdown of the installation, after the loading of a container with irradiated fuel, it is necessary to cool down said container. To this effect (FIG. 6), the invention provides a cooling device for container 12, comprising a tubing 64, integrated with or fixedly attached to the cart framework 26, and which covers the container over the entire height of its cooling fins 66, the cooling being provided by water circulating in the space between tubing 64 and the container, said circulation being provided by flexible ducts 68, 68'. The lower and upper fluid tightness of the tubing on the container is provided by standard seals 62. The fluid continuity of the tightness between the loading or unloading pit or tank 22 and container 12 is provided by means of a conventional metallic bellows 70 (FIG. 7) which is concentric with a sleeve 70' extending downwardly from the loading pit 22, the bellows 70 being held at an upper end thereof by a flange 71 connected to the underside of the loading pit 22. According to the invention, the fluid tightness is provided between the bellows 70 and container 12 at the level of the bearing surface 72 of the latter which receives the plug, in order to avoid any contamination of the upper part of said container. The system for maintaining the bellows is disclosed in French Pat. No. 80 26 360 filed on Dec. 12, 1980 and published under No. 2 496 329 in the name of the assignee of the present invention. This system includes a series of springs 74 maintaining the bellows 70 in its idle position, by exerting an upward force on shafts 76 the respective lower ends of which are rigidly connected to a flange 78, so-called movable abutment flange, which provides the connection between a gasket carrying flange 80 and the bellows lower end. According to the invention, the metallic bellows 70 can be disassembled from the bottom, without it being necessary to disassemble the springs 74 and flange 78, by disassembling a lower flange 82 maintaining the whole system in position. With reference to FIG. 8, a description will now be given of a bellows engaging means which, in this embodiment, are mounted on a tubing 84 of cart 10 and which allow, once the cart is positioned underneath penetration shaft 20, to engage the bellows 70 and pull it downwardly in order to hold gaskets 81 on the gasket carrying flange 80 against container upper bearing surface 72 and to ensure the fluid tightness provided by the bellows. Said bellows engaging means, which are similar to those disclosed in the hereabovementioned French patent, comprise four assemblies identical to that shown in FIG. 8, it being understood that their number can vary as a function of the efforts which have to be exerted for pulling the bellows. Each assembly includes a treated steel screw shaft 86, provided with an frustoconical insertion end 86', the lower end of said screw being provided with a roll or roller abutment 88 accommodating the axial stress. Each screw 86 cooperates with a spherical collar nut 90 provided on the movable abutment flange 78. In the embodiment shown here, each spherical collar nut 90 is held within a base 92 with prevents the collar nut 90 from rotation being rotated, while leaving a clearance affording a sufficient freedom for the motion of the collar nut 90. Each collar nut 90 is applied on base 92 by springs 94 exerting a slight pressure on the collar nut, for facilitating easy engagement of screw 86 at the beginning of the screwing operation, described below. Base 92 is mounted on an adjustment flange 96 via resilient devices, made here of spring washers 98 having a double function: 1--to protect step-down gears 100 of a driving mechanism for screws 86, described below, when stopped in mechanical abutment, and PA0 2--provide a free expansion of the container while remaining locked, without introducing a new excessive stress in the system. The adjustment flange 96 also allows positioning of the axis of nut 90 with respect to the axis of screw 86, the cart serving as a jig. According to the invention, the screw devices hereabove described are designed so as to accommodate a large offset between the axis of nut 90 and that of screw 86 in order to obtain a greater freedom of positioning of the cart underneath penetration shaft 20. To this effect, the collar of nut 90 is designed so as to allow a displacement of the cart of at least 4 mm with respect to the penetration shaft, when there is an earthquake, while still ensuring the thighness. Still according to the invention (FIG. 9), the resilient mounting devices for collar nuts 90 formed by the spring washers 98 are used as a force limiting system at the contact between the gasket carrying flange 80 collar 96 and the container 12, by measuring the relative displacement between the adjustment flange 96 and the base 92. To this effect, the invention provides cam means, such as a cam 102, mounted on the adjustment flange 96, and an electrical contact 104 on the base 92, for the detection of said relative displacement (of course, a reverse disposition can also be envisaged without departing from the scope of the invention by mounting cam 102 on base 92 and contact 104 on flange 96). The relative displacement thus detected corresponds to the force exerted between the container 12 and the bellows 70"; due to the compression effected by the screw device. Each screw 86 stops turning in a locked position due to the information provided to suitable control means by the electrical contact 104 operated by cam 102. Each screw 86 is driven in rotation by a motor 106 and a step-down gear 100 unit, said motor/step-down gear unit comprising a braking system 108 with manual unlocking 110. The driving of screw 86 is obtained via a sheath 112 keyed to the step-down gears 100, there being two grooves and two keys 114 providing a rotating connection between screw 86 and the sheath 112. The latter is guided by a hollow shaft of the step-down gear 100 and it comes to bear against the ball or roller abutment 88, fixed onto the tubing 84 of the cart, thereby allowing introducing all the axial efforts into the cart, and thereby protecting the step-down gear. The sheath 112 provides the angular adjustment of the first thread of screw 86 via a cam 116 and an electrical device 118, the synchronous motor 106 providing the rotation motion. The lower end of screw 86 is fixed by an articulated connection 120 at the end of the shaft 122 of a double action pneumatic jacket 124. The hereabove described system being identical to the corresponding system disclosed in the aforementioned French patent, its operation will not be described and the reader is invited to refer to the corresponding description of said prior patent. According to the invention, a revolution counting device 126 is provided for each screw system, such as adjacent screw 86, for detecting and signalling a possible lack of synchronization of the rotation of the screw systems, any lack of synchronization of one of the screw systems causing the stoppage of all the screws. According to the invention, when an incident occurs on a screw, it is possible to put out of order the screw which is diametrically opposite thereto and to go on operating all the other screws, either for locking them to obtain the fluid tightness, or for unlocking them in order to remove the container from the penetration shaft. According to the invention, an emergency manual control can be provided, which can be coupled to each screw so as to be able to effect a manual coupling or uncoupling thereof. Finally, according to the invention, when a screw is jammed in a corresponding nut, it is possible to cut off the jammed screw underneath the armored protection plates, said system being such that after disconnecting the bellows from the container the portion of the screw which is jammed in the nut does not prevent the translation of the container on its cart, and therefore a resetting of the system in a "safety" position is possible. Obviously, this invention is not limited to the various embodiments described and shown, and it encompasses all possible variations thereof.
	claims	1. A maintenance system adapted for making a maintenance plan for consumable parts of an apparatus that is a maintenance target, comprising:an interval information acquiring unit configured to acquire information related to a combination of a visit interval that prescribes a time interval at which a visit should be made for maintenance operation for each consumable part, and a replacement interval, associated with the visit interval, that prescribes a time interval at which each consumable part should be replaced;a counter value acquiring unit configured to acquire a counter value that indicates actual use of consumable parts in the apparatus; anda maintenance plan calculating unit configured to calculate timing at which a next visit should be made for the apparatus, and a consumable part that should be replaced at the timing, on the basis of the information acquired by the interval information acquiring unit and the counter value acquired by the counter value acquiring unit. 2. The maintenance system according to claim 1, wherein the consumable parts include a cartridge in which plural consumable parts having different functions from each other are formed integrally as a unit. 3. The maintenance system according to claim 1, comprising:a replacement difficulty judging unit configured to judge whether or not the consumable part that should be replaced, calculated by the maintenance plan calculating unit, is a component that can only be replaced by a serviceman carrying out maintenance operation for the apparatus; anda notifying unit configured to, if the replacement difficulty judging unit judges that the consumable part is a component that can only be replaced by the serviceman, issue a notification that a visit should be made for the apparatus in order to replace the component. 4. The maintenance system according to claim 1, comprising:a visit interval calculating unit configured to calculate the visit interval for each consumable part on the basis of failure rate distribution of each consumable part;a replacement interval calculating unit configured to calculate the replacement interval for each consumable part on the basis of failure rate distribution of each consumable part; anda combination calculating unit configured to calculate information related to a combination of a time interval at which a visit should be made for maintenance operation and a consumable part that should be replaced at the timing, on the basis of the visit interval calculated by the visit interval calculating unit and the replacement interval calculated by the replacement interval calculating unit;wherein the interval information acquiring unit acquires the information calculated by the combination calculating unit. 5. The maintenance system according to claim 4, wherein the visit interval calculating unit randomly calculates the visit interval, and the replacement interval calculating unit randomly calculates the replacement interval, andthe combination calculating unit finds a combination of a visit interval and a replacement interval that minimizes a predetermined cost, on the basis of the visit interval calculated by the visit interval calculating unit and the replacement interval calculated by the replacement interval calculating unit. 6. The maintenance system according to claim 5, wherein the visit interval calculated for each consumable part by the visit interval calculating unit is set to be longer than the replacement interval calculated by the replacement interval calculating unit. 7. The maintenance system according to claim 5, wherein the predetermined cost is a sum of labor cost required for maintenance operation by a serviceman, material cost of consumable parts, and amount of loss caused by unavailability of the apparatus that is the maintenance target to a user. 8. The maintenance system according to claim 5, wherein the combination calculating unit performs search processing using a Monte Carlo method or a genetic algorithm on the basis of the visit interval calculated by the visit interval calculating unit and the replacement interval calculated by the replacement interval calculating unit, thereby finding a combination of a visit interval and a replacement interval that minimizes the predetermined cost. 9. The maintenance system according to claim 5, wherein the visit interval calculating unit and the replacement interval calculating unit calculate, on the basis of failure probability distribution of each consumable part, a value close to an interval with which the failure probability is predicted to be equal to or higher than a predetermined probability. 10. A maintenance system for making a maintenance plan for consumable parts of an apparatus that is a maintenance target, comprising:interval information acquiring means for acquiring information related to a combination of a visit interval that prescribes a time interval at which a visit should be made for maintenance operation for each consumable part, and a replacement interval, associated with the visit interval, that prescribes a time interval at which each consumable parts should be replaced;counter value acquiring means for acquiring a counter value that indicates actual use of consumable parts in the apparatus; andmaintenance plan calculating means for calculating timing at which a next visit should be made for the apparatus, and a consumable part that should be replaced at the timing, on the basis of the information acquired by the interval information acquiring means and the counter value acquired by the counter value acquiring means. 11. The maintenance system according to claim 10, comprising:replacement difficulty judging means for judging whether or not the consumable part that should be replaced, calculated by the maintenance plan calculating means, is a component that can only be replaced by a serviceman carrying out maintenance operation for the apparatus; andnotifying means for, if the replacement difficulty judging means judges that the consumable part is a component that can only be replaced by the serviceman, issuing a notification that a visit should be made for the apparatus in order to replace the component. 12. A maintenance method adapted for making a maintenance plan for consumable parts of an apparatus that is a maintenance target, comprising:acquiring information related to a combination of a visit interval that prescribes a time interval at which a visit should be made for maintenance operation for each consumable part, and a replacement interval, associated with the visit interval, that prescribes a time interval at which each consumable parts should be replaced;acquiring a counter value that indicates actual use of consumable parts in the apparatus; andcalculating using a CPU, timing at which a next visit should be made for the apparatus, and a consumable part that should be replaced at the timing, on the basis of the acquired information related to the combination of the visit interval and the replacement interval, and the acquired counter value. 13. The maintenance method according to claim 12, wherein the consumable parts include a cartridge in which plural consumable parts having different functions from each other are formed integrally as a unit. 14. The maintenance method according to claim 12, comprising:judging whether or not the consumable part that should be replaced is a component that can only be replaced by a serviceman carrying out maintenance operation for the apparatus; andif the consumable part is judged to be a component that can only be replaced by the serviceman, issuing a notification that a visit should be made for the apparatus in order to replace the component. 15. The maintenance method according to claim 12, comprising:calculating the visit interval for each consumable part on the basis of failure rate distribution of each consumable part;calculating the replacement interval for each consumable part on the basis of failure rate distribution of each consumable part; andcalculating the information related to the combination of the time interval and the replacement interval, on the basis of the visit interval as calculated and the replacement interval as calculated. 16. The maintenance method according to claim 15, wherein the visit interval is randomly calculated, and the replacement interval is randomly calculated, andthe combination of the visit interval and the replacement interval that minimizes a predetermined cost is found, on the basis of the visit interval as calculated and the replacement interval as calculated. 17. The maintenance method according to claim 16, wherein the visit interval calculated for each consumable part is set to be longer than the replacement interval. 18. The maintenance method according to claim 16, wherein the predetermined cost is a sum of labor cost required for maintenance operation by a serviceman, material cost of consumable parts, and amount of loss caused by unavailability of the apparatus that is the maintenance target to a user. 19. The maintenance method according to claim 16, wherein the combination of the visit interval and the replacement interval that minimizes the predetermined cost is found using a Monte Carlo method or a genetic algorithm on the basis of the visit interval as calculated and the replacement interval as calculated. 20. The maintenance method according to claim 16, wherein the visit interval and the replacement interval are each calculated on the basis of failure probability distribution of each consumable part and to have a value close to an interval with which the failure probability is predicted to be equal to or higher than a predetermined probability.
	summary
	summary
	description	The present invention relates to a process automation system for determining, monitoring and/or influencing different process variables and/or state variables in at least one manufacturing or analytical process. The process automation system includes: at least one control station; and a plurality of field devices, which measure, monitor or influence the process variables and/or state variables. Fundamental progress in microelectronics and sensor technology have, in recent years, led to a miniaturization of field devices and to an integration of functionalities into the field devices, which has brought about in automation technology an effective and economical application of integrated, decentralized systems. In such field devices, embodied as sensors and actuators, not only are measured-values ascertained, but, also, the measured values are preprocessed and linearized in the sensor or in the actuator. In given cases, a self-diagnosis of the sensor or actuator is performed in the sensor or in the actuator. Prerequisite for introduction of these decentralized functionalities into a closed automation concept having “intelligent” sensors and actuators is increased information- and data-exchange of these decentralized units, among one another and/or with a control station. In process automation technology, for this reason, in recent years, a number of fieldbus systems have arisen, which relate either to company-specific areas of application (e.g. BITBUS, CAN, MODBUS, RACKBUS) or meet an international standard (e.g. HART, PROFIBUS-PA, Foundation FIELDBUS, Ethernet). The large number of fieldbus systems currently used in industrial automation and process control technology will not be explicitly explored. Instead, they will be referenced simply with the generally applicable term, “fieldbus”. Currently, for measuring arrangements including at least one sensor and/or one measurement transmitter, a plurality of diagnostic functions are provided. Thus, today, the diagnosis and monitoring of measured- or state-variables by means of warning- and alarm-limit-values of a minimum- and maximum-value belong to the state of the art. For diagnosis of individual attributes, both methods and apparatus, e.g. in the form of measuring field devices, are known, which enable statements to be made concerning functional ability of the measuring field device or its remaining life expectancy; compare, for example, the published German Patent application DE 102 55 288 A1. Such discloses prediction of a point in time, when maximum life expectancy of the field device will probably be reached. Thus, from influencing variables registered supplementally in addition to the process variables and from estimation of their influence on life expectancy or functional ability of the field device and/or individual modules or components thereof, a statement can be made concerning remaining service life. In published German patent application DE 10 2004 340 042 A1, on the basis of an access counter, a remaining service life prognosis is calculated for the data memory of a field device. Published German patent application DE 10 2004 012 420 A1 takes into consideration, furthermore, also the current characteristics of the measuring environment, as well as the history of the process conditions. As a function of a loading model, thus, an evaluation of the already transpired loading of the measuring system is possible. Based on this evaluation, statements can be derived concerning remaining service life of the system. In this publication only two measured variables (pH-value, temperature) ascertained locally in the field device are taken into consideration for diagnosis as regards loading of the sensor. Although these discussed manners of proceeding already enable a certain measure of diagnostic ability, an improved knowledge concerning the qualitative state of a measuring arrangement in measurement operation would be desirable. Due to the decentralized distribution of the individual process components, or field devices, in a process automation system, it is necessary, that information and measured values of the individual field devices be forwarded, for the purpose of diagnosis and analysis of the field devices and their measured values, to all other process components of a process and/or to the control station, for example, via the fieldbus. An object of the invention is to provide a decentralized process automation system, which makes available, to each field device of a process, the entire, ascertained information concerning such process. For achieving the object, a process automation system for determining, monitoring and/or influencing different process variables and/or state variables in at least one manufacturing or analytical process is provided. The process automation system includes: at least one control station; and a plurality of field devices, which measure, monitor or influence the process variables and/or state variables. In each field device, there is provided at least one sensor for ascertaining a measured value of a process variable and/or state variable and/or one actuator for influencing a process variable and/or state variable by means of an actuating value. Each field device makes available the cyclically or acyclically ascertained, measuring-device-specific, measured values and/or actuating values of the process variable and/or state variable to every other field device of the process automation system, so that available to each field device as information are all ascertained measured values and/or actuating values of the manufacturing or analytical process and that current information of all ascertained measured values and/or actuating values of the process variables and/or state variables is available to each field device as a current process-state-vector. An especially advantageous further development of the process automation system of the invention provides that a digital fieldbus is provided, via which the field devices communicate with the control station and among one another, wherein each of the field devices, continuously or cyclically, jointly reads the measured values and/or actuating values of the other field devices of the manufacturing or analytical process provided on the digital fieldbus and stores these jointly read, measured values and/or jointly read, actuating values as information at predetermined positions in the process-state-vector. Each field device jointly reads the measured values placed by the others on the fieldbus, and stores them, depending on characteristic variable, priority indicator and/or time stamp at predefined positions in the process-state-vector. The process-state-vector is formed directly in the individual field devices. Thus, the fieldbus is not, as in the preceding example of an embodiment, supplementally timewise occupied by the transmission of the process-state-vector from the control station. If a new field device is initialized on the fieldbus, or on a two-wire-connecting line, during operation of the process automation system, then such field device asks, for example, another field device or the control station, to provide the current process-state-vector. Through this request for transmission of the current process-state-vector, the new field device can perform in the process automation system, directly after the initializing in the fieldbus and the providing of the process-state-vector, the diagnosis of the measured values and the field device function, as well as the plausibility monitoring of the measured values. In a preferred form of embodiment of the invention, it is provided, that the individual field devices transmit the field-device-specific, measured values and/or the field-device-specific, actuating values, via a two-wire-connecting line and/or a fieldbus, to the control station cyclically or upon request, and the control station transmits the collected information in the form of the process-state-vector, cyclically or upon request of the field devices, to all field devices. In this embodiment of the invention, the individual measured values of a process are collected in the control station and arranged and stored in a process-state-vector. This process-state-vector is then transmitted at the same time to each individual field device, so that in each field device the same process-state-vector is present for additional processing. In an additional preferred embodiment of the process automation system of the invention, it is provided, that a control/evaluation unit is present in the field devices and/or in the control station, wherein the control/evaluation unit uses the information of the process-state-vector for reviewing plausibility of the current measured values ascertained with the field device and/or the current actuating values of the current process variable and/or for function-diagnosis of the field device. On the basis of the measured values stored in the process-state-vector of other field devices in the process, a plausibility review of the measured value ascertained in the current field device can be done. For example, in the case of measuring the draining of fill substance from the container through a flow measuring device, taking into consideration the container geometry, a fill level change can be deduced. The calculated fill level change and the fill level change measured with a fill-level measuring device can be compared with one another, and, thus, a statement made concerning accuracy, and reproducibility, of the measured value. In an advantageous form of embodiment of the invention, a control/evaluation unit is provided in the field devices and/or in the control station, wherein the control/evaluation unit ascertains, from the information of the process-state-vector and from a predetermined mathematical model, the life expectancy and/or need for maintenance of the field device and/or individual electronics modules and/or the total system. Another advantageous embodiment of the invention is that in which a control/evaluation unit is provided in the field devices and/or in the control station, wherein the control/evaluation unit analytically and/or numerically derives from the information of the process-state-vector at least one other measured value characterizing the process. Some process variables and/or state variables, such as, for example, the density of the fill substance, cannot be ascertained directly by means of a sensor. The control/evaluation unit in the field device derives this density, for example, from a plurality of pieces of information of the process-state-vector. In an especially preferred form of embodiment of the invention, it is provided, that, in the case of use of a process automation system in at least two manufacturing or analytical processes, the process-state-vector is supplied with a characteristic variable characterizing the manufacturing or analytical process and serving for identification and/or for grouping of all ascertained measured values of the field devices with the manufacturing or analytical process to which they belong. Through this characterizing characteristic variable, it is possible to assign the individual measured values of the different field devices to the processes with which they are associated. To this end, it is provided, that this indicator is stored in the field device, so that the field device can be associated with a certain process. This associating of the measured values to a process is necessary, since, in the case of diagnosis of the measured values or the states of the field devices and/or in the case of plausibility review of the measured values of the field devices, then such will be on the basis of equal process conditions and measuring conditions. A purpose-supporting embodiment of the invention includes providing in the process-state-vector a time stamp characterizing the point in time of the ascertaining of the measured values. This time stamp is utilized, in order to collect measured values, which were ascertained at the same point in time or in a predefined period of time, together in a process-state-vector. In this way, it is assured, that older measured values are not compared with younger measured values, in case, for example, process conditions have changed in the intervening time. Furthermore, for a trend- or historical-investigation of the measured values, the point in time of their determining is necessary, in order that an informative and time-based presentation of the trend or the history of the measured values can be performed. For forming the time average of the measured values, for example, from the time stamp, the time span is ascertained, in which the measured values were ascertained. Moreover, by the association of the measured values to the point in time of their registering, signals as a function of time and trends can be ascertained. From a trend, for example, also a statement concerning the aging behavior of the sensor or actuator can be made. In an advantageous form of embodiment of the process automation system of the invention, it is provided, that the individual measured values and/or actuating values of the process variables and/or state variables are arranged at predetermined locations in the process-state-vector. Through unified arrangement of the different measured values, such as e.g. pressure, temperature, fill level, flow, e.g. flow rate, pH-value, conductivity and viscosity, in the process-state-vector, the position of a measured value is fixed in the process-state-vector. Therefore, for example, the measured value does not have to carry units in the process-state-vector, in order that it can be identified. Stored in the field device is the information concerning at which position in the process-state-vector the specific measured value is located, what units it has and its order of magnitude. If, in a process, a certain measured value cannot, based on, for example, a missing, or malfunctioning, field device, be ascertained, then stored at its position in the process-state-vector is a zero, or some other indicator that no measured value is present. A supplementing embodiment of the invention includes, that a priority designation of the measured values is provided, for indicating rank of the record of the measured value or actuating value in the process-state-vector when a plurality of measured values or actuating values of a single process variable exists. For example, based on the accuracy of measurement, with which a measured value was ascertained by a field device, a priority indicator is assigned, which fixes, which measured value of a plurality of measured values of the process variable, e.g. temperature, is entered in the process-state-vector. Furthermore, the priority indicator establishes, that measured values of the same process variable with a lower priority in the process-state-vector can be over-written by higher-ranked, measured values. An advantageous embodiment of the invention provides that the control- and evaluation-unit encrypts the information of the process-state-vector. Through the encryption of the information of the process-state-vector, only selected field devices can jointly read and again decode the information of the process-state-vector. Through the encryption of the process-state-vector, the information and measured values concerning the process are protected. An advantageous form of embodiment of the invention includes that, in each field device or in the control station, historical information concerning older measured values and/or older actuating values is stored with the current information of current measured values in a process-state-matrix. For determining the curve as a function of time and/or the trend of the measured- and actuating-values, it is advantageous to have the current and older values present in a fixed form. In an advantageous form of embodiment of the invention, it is provided, that the control/evaluation unit ascertains, from the current information and the historical information, the life expectancy and/or need for maintenance of the field device and/or checks the plausibility of the current measured value and/or current actuating values of the current process variable ascertained with the field device and/or ascertains the function-diagnosis of the field device and/or the trend of the measured values. FIG. 1 shows a process automation system 1 of the invention. Process automation system 1 is constructed of a control station 4 and a plurality of field devices 5 distributed between a container of a first process 2 and a container of a second process 3. The individual field devices 5 communicate among one another and with the control station 4 via a fieldbus 15 and/or two-wire-connecting lines 14. Integrated in the control station 4 is a control- and evaluation-unit 16, which carries out the control of the automation process, evaluation of the measured values Mx or actuating values Ax of the individual field devices 5 and/or analysis and diagnosis of the information I and the measured values Mx of the field devices 5. A process variable G, or procedure variable, is a physical variable, which occurs exclusively in the case of state changes and, as a result, is path dependent. The measured values Mx and actuating values Ax are values of process variables G or state variables Z of the process 2, 3 ascertained from the sensor 11 or actuator 12 of the field devices 5. In the first process 2 in FIG. 1, for example, two fill level measuring devices 6, a limit-level measuring device 7 and an analytical measuring device 8 are provided. Integrated between the containers of the first process 2 and the second process 3 is a flow measuring device 9, which ascertains transport of fill substance between the two containers of the processes 2, 3. The field devices 5 of the first process 2 communicate via a digital fieldbus 15, such as e.g. Profibus PA or Foundation Fieldbus, with one another and/or with the control station 4. Analogously to hardwired communication via a digital fieldbus 15, communication can also be accomplished via a corresponding wireless communication unit according to known standards, such as e.g. ZigBee, WLAN and Bluetooth. This is, however, not explicitly embodied in the illustrated example of an embodiment of FIG. 1. Integrated in the second process 3, for example, as field devices 5 are a pressure measuring device 10, a temperature measuring device 17 and an actuator 13 for operating a valve, these communicating via a direct two-wire-connecting line 14 with the control station 4 or among one another. Communication via the two-wire-connecting line 14 occurs, for example, according to the HART-standard, which modulates onto an analog, 4-20 mA, electrical current signal a digitized, high-frequency signal as an additional information carrier. In the current state of the art, only measured values Mx and/or information I concerning the process 2, 3 are known, which are ascertained in or from the field device 5 itself. However, this information I concerning the process 2, 3 is not sufficient for calculating the need for maintenance or the life expectancy of the field device 5. In order currently in the case of field devices 5 to obtain a statement concerning their life expectancy or need for maintenance, on the one hand, information I is derived from the measured values Mx directly present in the field device 5. On the other hand, however, also other measured values Mx of other process variables G and/or state variables Z are necessary for an exact and/or expanded, diagnostic function of the field device 5, and these cannot be measured directly or indirectly by means of the one sensor 11 in the field device 5. Furthermore, it is, for reasons of cost and/or space, most often, however, not possible to integrate in the field device 5 an additional sensor 11 for measuring the measured values Mx of a process variable G needed for the diagnosis. Most often, the additional information I of the process 2, 3 is, however, already present by way of other field devices 5 of the individual processes 2, 3 distributed in the process automation system 1 and must only be appropriately provided. A place in the process automation system 1, where all information I of the process 2, 3 comes together, is, for example, the control station 4. Various field devices 5 of different manufacturers can be connected to the control station 4. The algorithms for executing the calculatory functions and diagnostic functions in the field device 5 are only known to the manufacturer of the device. It is, thus, a disadvantage to implement the device-specific algorithms of the calculatory functions and diagnostic functions directly in the control station 4, since it is then necessary to store and, when required, to invoke all device-specific algorithms of the different field devices 5 of different manufacturers in the control station 4. For these reasons, it is of advantage, to implement the calculation of life expectancy and the diagnosis directly in the field devices 5, since, in this case, only the one device-specific algorithm of the calculatory functions and diagnostic functions needs to be present in the field device 5. However, it is then also necessary, that all information I of the process P needed for execution of the algorithm be available to the field device 5. A first form of embodiment of the invention is, therefore, that, in the control station 4, all measured values Mx are collected as information I in the form of a unified process-state-vector P and this unified process-state-vector P is transmitted to the field devices 5 of the process 2, 3. In the field devices 5, for example, by means of the additional information I of the created process-state-vector P, calculations for life expectancy of the sensor 11 or the field device 5 or for a plausibility determination of the measured value Mx of the field device 5 can be performed. Furthermore, it is possible through direct comparison of the different measured values Mx of a shared process variable G to lessen the measurement error, and/or measurement uncertainty, of the measuring. Available to each field device 5 is, separated according to the processes, the same information I in the form of a unified process-state-vector P. The associating of the field devices 5 to the individual processes 2, 3 occurs, for example, by means of a characteristic variable K characterizing the manufacturing or analytical process and assigned to the measured values Mx on the fieldbus 15 or the two-wire-connecting lines 14, thus enabling an assigning of the individual measured values Mx to the process-state-vector P describing the relevant process 2, 3. An advantage of this embodiment is, that the operator of a process automation system need not exactly know, which additional information I of the individual connected field device 5 is required, but, instead, the field device fetches the necessary additional information I from a uniform process-state-vector P. In a second form of embodiment of the invention, the measured values Mx of the individual field devices 5 of a particular process 2, 3 are transmitted according to a standardized transmission protocol, such as e.g. Profibus PA or Fieldbus Foundation, via the digital fieldbus 15. The corresponding measured values Mx are jointly read by each individual field device 5 on the digital fieldbus 15 and stored in a control-evaluation unit 16 in memory as a process-state-vector P. The automatic, joint reading of the different measured values Mx on the digital fieldbus 15 and the automatic placing of the different measured values Mx in a process-state-vector P is then possible, because the different measured values Mx are unequivocally identifiable. This can be effected by a system-wide, unique identifier, such as e.g. a bus address of the field device 5, by associating with the identifier a physical/chemical measured variable for the field device 5 or the sensor 11, along with the dimension of the measured variable—thus, for example, temperature in degrees Celsius. Alternatively, the different measured values Mx of a process 2, 3 can be characterized on the digital fieldbus by a designating element specifying the measured value Mx. Associated with the measured values Mx and actuating values Ax transmitted via the two-wire-connecting lines 14 or the fieldbus 15 to the additional field devices 5 and/or the control station 4 is a designating element, on the basis of which the measured values Mx are associated in the dimension and unit of measurement of the corresponding process variable G. For example, in the case of the transmission of temperature as measured value, the unit of measurement, degrees Celsius, and the order of magnitude, 1, are sent via the fieldbus 15 or the four-wire-connecting line 14 as designating element of the measured value Mx. An option is also to transmit as designating element a predefined variable via the fieldbus 15 or the two-wire-connecting line 14. The predefined variable is stored in the field device 4 in the control- and evaluation-unit 16 in combination with a unit of measurement characterizing the measured value Mx and with an order of magnitude of the corresponding measured value Mx. The specific measured values Mx of each field device 5, such as e.g. temperature, pressure, pH-value in the process 2, 3, are stored by the control- and evaluation-unit 16 in the field device of the process-state-vector P at a predetermined position in the process-state-vector P. Each control- and evaluation-unit 16 in a field device 5 knows on the basis of the unified arrangement of the individual, different, measured values Mx, the position in the process-state-vector, where the corresponding measured value M, such as e.g. the pressure value, is stored. This second embodiment has the advantage, that, for example, the knowledge concerning the calculation of the life expectancy as a function of all process variables G and/or state variables Z and/or state variables Z no longer can be calculated only in the control station 4, but, instead, that this diagnosis and analysis can occur directly in and by the field device 5. In the following, a selection of application examples of the process-state-vector in a process automation system 1 is presented. In addition to determining pH-value by means of an analytical measuring device 8, also the process pressure is calculated as information I. From this, for example, the next date for a recalibration, or the life expectancy of the pH-electrode, can be calculated in the field device 5. The propagation velocity of a freely radiating, fill-level measuring device 6 utilizing microwave radiation is pressure-dependent. For calculating the exact travel time of a microwaves-pulse and, thus, for determining exact fill level of a fill substance in a container, the exact pressure in the process 2, 3 must be known. From the process-state-vector P, the fill-level measuring device 6 reads the measured value Mx of pressure of the pressure measuring device 10 from the same process 2, 3. Thus, an exact measuring of the fill level is made possible, taking into consideration the exact pressure in the process 2, 3. In the case of a fill-level measuring device 6 ascertaining fill level in a container of the process 2, 3 by means of travel time of an ultrasonic-pulse, a temperature sensor is integrated in the ultrasonic transducer for determining temperature of the process 2, 3. Through a measured value Mx of the temperature from the process-state-vector P, for example, of a temperature measuring device 17 in the same process, it is possible to conduct a plausibility determination of the measured value ascertained with the temperature sensor of the ultrasonic transducer. When the distribution of the field devices 5 in processes 2, 3 is known, then, also, plausibility can be determined between the measured values Mx. FIG. 2 illustrates production of a process-state-vector P and/or a process-state-matrix PM in the control/evaluation unit 16 in a field device 5 or in a control station 4. Via the fieldbus 15 or the two-wire-connecting lines 14, the individual measured values Mx and/or actuating values Ax are collected and stored at their appropriate positions in the process-state-vector P or in the process-state-matrix PM. On the basis of the characteristic variable Kx and the time stamp Tx, the measured values Mx or the actuating values Ax of the processes 2, 3 are associated with the appropriate process-state-vector P or a column in the process-state-matrix PM. The registering point in time, or registering time period, of the ascertaining of the measured values Mx and/or actuating values located in this column is stored, for example, as a time stamp in the last row of the corresponding column, so that the time behavior of the measured values Mx and actuating values Ax in the process-state-matrix PM can be ascertained. The measured values Mx-t and/or the actuating values Ax-t are characterized according to their assignment to a current time stamp Tx. As already described above, the measured values Mx and/or the actuating values Ax are either jointly read directly on the fieldbus 15 by the connected field devices 5 and stored in the field devices 5 and at the assigned positions in the process-state-vector P or the process-state-matrix PM, or the measured values Mx and actuating values Ax are collected in a central unit, e.g. the control station 4, as process-state-vector P or process-state-matrix PM and the entire process-state-vector P or the entire process-state-matrix PM is sent via the fieldbus 15 or the two-wire-connecting line 14 back to the individual field devices 4. Thus, present at the same time and conformedly in each field device 4 are all ascertainable measured values Mx and/or all settable actuating values Ax of the state variables Z and/or process variables G of the process 2, 3.
043119123	description	DESCRIPTION OF SPECIFIC EMBODIMENTS Turning now to FIG. 1, the invention will be described with respect to a preferred application in a radioactive well logging system and particularly one in which the neutron source is operated in a pulsed mode. The well logging system comprises a logging tool 3 which is suspended from a cable 4 within a well 5 traversing a subterranean formation of an interest indicated by reference numeral 6. The well bore may be lined or unlined with casing but normally will be filled with a fluid such as drilling mud, oil or water. Signals from the logging tool are transmitted uphole via suitable conductors in the cable 4 to an uphole analysis and control circuit 8. Circuit 8 operates on the downhole measurements and applies one or more output functions to a recorder 9. In addition, circuit 8 transmits certain control functions to the logging tool via conductors in cable 4. As the logging tool is moved through the hole, a depth recording means, such as measuring sheave 10, produces a depth signal which is applied to recorder 9, thus correlating the downhole measurements with the depths at which they are taken. The logging tool 3 comprises a pulsed neutron source 12, a downhole power supply 14 for the source, and a radiation detector 15, which responds to primary or secondary radiation in the formation in response to the output of the pulsed neutron source. For example, the detector 15 may be a gamma ray detector, a thermal neutron detector or an epithermal neutron detector. While only one detector is shown, it will be recognized that such logging tools may comprise a plurality of detectors responsive to similar or dissimilar radiation. The pulsed neutron source is an accelerator-type neutron tube comprising a replenisher section 16, an ionization section 18, and a target section 19. Replenisher section 16 may comprise replenisher element 16a which releases deuterium gas in response to an applied DC or AC voltage from power supply 14. Target section 19 comprises a tritium target 19a. The target section also includes an extraction-focusing electrode assembly as describe hereinafter and a negative high voltage supply (not shown) which functions to direct ions from the ionization section 18 to the target 19 while suppressing the counter current flow of secondary electrons produced by ion impact on the target. The ionization section 18 is a Penning-type ion source and includes anode means 18a and cathode means 18b and 18c. The neutron source 12 may be operated in a continuous or in a pulsed mode. In either mode of operation, deuterium gas released upon the application of power to the replenisher element 16 enters the ionization section 18 where the gas molecules are ionized by a positive (with respect to cathodes 18b and 18c) ionization voltage applied across anode 18 and cathodes 18b and 18c. The deuterium ions formed in the ionization section are then accelerated toward the target 19a by a negative voltage applied to the target section. For example, a positive voltage or voltage pulse with an amplitude from a few hundred volts to a few kilovolts may be applied to anode member 18a and a -100 kilovolt voltage applied to target section 19. The Penning ionization section of accelerator-type neutron tube may be of the "cold cathode" or of the "hot cathode" type. In the cold cathode source, the primary electrons are produced by field emission when a positive voltage pulse is applied to the anode. In the hot cathode type of source, electrons are initially produced by thermionic emission from an electrically heated filament. The cold cathode source suffers the disadvantage, which is of particular significance when the neutron source is operating in a pulsed mode, of having a time lag before the electron flux reaches a sufficient value for optimum ionization of the accelerator gas. Thus, upon applying a positive voltage pulse to the anode there normally is a period of from about 3-10 microseconds in which the electron flux builds up to an equilibrium value. The hot cathode source does not suffer this disadvantage because electrons are instantly available from thermionic emission. However, the hot cathode source requires an additional high voltage power supply which is particularly significant in the case of downhole logging tools where the power requirements must be met by transmission from the surface. The concentration of ionized accelerator gas is dependent upon the accelerator gas pressure, i.e., the concentration of gas molecules in the replenisher section and the efficiency of the ionization section. Ionization efficiency is directly related to the flux and energy of free electrons in the ionization section. Therefore, a relatively inefficient ionization process would require a relatively high accelerator gas pressure, i.., a higher concentration of gas molecules. Conversely, the accelerator gas pressure can be significantly reduced by increasing the electron flux in the ionization section. A very significant increase in neutron production is realized by having an ion source that operates efficiently at low gas pressure in the range of a few microns of Hg pressure. This relationship holds true for continuous ion sources as well as for the pulsed ion sources. The efficiency of the ionization section of the neutron source may be significantly increased by formulating the active surface of one or both of the cathodes with a material having a secondary electron emission factor of 2 or more. Materials which are especially useful in formulating the cathode surfaces including metallic oxides such as aluminum oxide, beryllium oxide, barium oxide, and magnesium oxide. Preferred metal oxides include beryllium oxide, aluminum oxide, and magnesium oxide since these materials are relatively stable in a low pressure environment of hydrogen or its heavy isotopes and, if sufficiently thick, are stable to ion impact. Of the oxides mentioned, beryllium oxide is most resistant to reduction in a hydrogen environment, and thus is especially suitable. Beryllium oxide provides a secondary electron emission factor which is in excess of 3, which is preferred. The efficiency of the ionization section of the neutron source further may be increased by formulating the active surface of at least one of the cathodes with a radioactive material which functions as a negative beta -.beta.-) ray emitter. Radioactive materials which are pure .beta.- ray emitters are especially suitable. If desired, both cathodes may be provided with active surfaces formulated of a .beta.- ray emitting material. Thus, one or more active cathode surfaces may be formulated of radioactive materials such as nickel-63, promethium-147, and carbon-14. Nickel-63 is particularly useful because it is a pure .beta.- emitter and it has a relatively long half-life of nearly 100 years. Nickel-63 can be readily plated onto a support element that is also a good conductor of magnetic flux such as soft iron, alloys of iron, nickel, etc. In an alternative arrangement, the active surface of one of the cathodes is provided with a .beta.- ray emitting material whereas the active surface of the other cathode contains a material having a secondary electron emission factor of at least 2 as described above. In a further configuration of the ionization section which may be employed in conjunction with cathode materials which function as .beta.- ray emitters and/or materials of a relatively high secondary electron emission factor as described previously as well as with more conventional cathode materials, one of the cathode members is formed with an active surface having a protuberant portion which extends axially into the chamber of the ionization section. A second cathode member has an aperture therein along the axis of the protuberant portion to provide for the extraction of ions from the ionization chamber. Preferably, the protuberant portion of the cathode surface is in a closer proximity to the ionization section anode than the remainder of the active cathode surface. This configuration of the cathode member functions to increase the electrical field at the peripheral edge of the protuberant portion and through the central interior of the ionization section, thus enhancing field emission of electrons at the peripheral edge, and therefore increasing the probability that the electron emitted from the cathode will travel to the opposing cathode rather than being collected by the anode. The cathode surface having a protuberant portion may be formulated of a .beta.- ray emitting material or a material having a secondary electron emission factor of at least 2. Where the active surface of the first cathode is formulated of a .beta.- ray emitting material, the active surface of the second cathode member may be formulated of a material having a secondary electron emission factor of at least 2. In addition, a portion of the active surface of the first cathode member, which is recessed with respect to the protuberant portion, may also be formulated of a material having a secondary electron emission factor of 2 or more. The cathode member interposed between the ionization chamber and the target chamber has an aperture therein to provide for the extraction of the ionized gas particles into the target chamber and ultimately into contact with the target. The side of the cathode member exposed to the target chamber is in the form of a recessed convergent surface with the aperture at the vortex thereof. Thus, the cathode surface may be the nature of a concave surface or the interior of a frustum. The extraction electrode interposed between the target and the cathode has a divergent projecting surface facing the recessed cathode surface. This electrode member has an aperture at the apex of the projecting surface through which the ions are accelerated to bombard the target. Thus, the surface of the extraction electrode as viewed from the cathode may be convex or frusto-conical in shape. The relationship of the cathode and extraction electrode surfaces are such as to concentrate the electrical field in the target chamber through the central portion thereof, thus enhancing the acceleration and extraction of ions through the cathode aperture to the target. In addition, the ratio of the aperture diameter to its length is not less than 0.75 and preferably is greater than one in order that the electrical field established in the target chamber will penetrate into the ion source and efficiently extract ions from the ionization chamber and furthermore to reduce ion neutralization. Ions contacting the interior surface of the aperture along its length are neutralized by capturing a free electron from the metallic cathode surface, therefore, ion neutralization is reduced by reducing the surface area of probable contact. Turning now to FIG. 2 of the drawing, there is illustrated a sectional view of the ionization and target sections of the neutron accelerator tube. The ionization section comprises primary and secondary cathode members 22 and 24 which define the upper and lower ends of the chamber 25 in which ionization of the accelerator gas actually takes place. Extending peripherally about the interior of the chamber 25 and located intermediate the cathode members 22 and 24 is an anode member 27. The anode member 27 is mounted on ceramic insulating collars 29 and 30 and thus is insulated from metallic sleeves 32 and 33 which, together with the cathode members, defines the remainer of the ionization chamber. Sleeves 32 and 33 and anode 27 are formed of a nonmagnetic or relatively low permeability metal such as an AISI 300 series austenitic stainless steel. An annular magnet 35 extends around the exterior of the ionization chamber and extends beyond the upper and lower ends of the anode member as shown. Extending from the anode member and between the ceramic collars 29 and 30, and through magnet 35, and an annular ring 37 is an electric lead 38 to a high voltage power supply for the anode. The cathode member 22 is provided with channels 36 through which accelerator gas from the replenisher section 16 flows into the ionization chamber. Cathode member 24, cathode member 22, and annular ring 37 are all formed of materials which are highly permeable to magnetic flux. For example, these elements may be formed of soft iron or certain stainless steels such as AISI series 410 stainless steel. The upper portion of cathode member 24 and the ring 37 together with the lower portion of cathode member 24 and cathode member 22 thus establish a high permeability flux path which extends initially outwardly from the ends of magnet 35 and then turns inwardly to the active surfaces of the cathode members. The high permeability paths established by cathodes 22 and 24 and ring 37 direct most of the magnetic flux between the north and south poles of magnet 35 into the interior of the chamber 25. In addition, it will be recognized from an examination of FIG. 2 that the strongest electric field established upon the application of a positive voltage to anode member 27 will extend from protuberant portion 42 of cathode member 22. This increases the probability that electrons emitted from cathode members 22 and 24 will impact the opposing cathode surface rather than being collected by anode member 27 and together with the spiraling action imparted by the increased magnetic field within the chamber increases the probability that the electrons will impact accelerator gas molecules to produce the desired ions. The surfaces of cathode members 22 and 24, which are exposed to the chamber 25, may be formed of any suitable material. Preferably, the surfaces are formed of a beta ray emitting material and/or a material having a high secondary electron emission factor as described previously. Thus, surface 22a on protuberant portion 42 may be formulated of nickel-63 and the recessed portion 22b of the active surface of cathode member 22 formulated of a material such as beryllium oxide. The active surface 24a of cathode member 24 may similarly be formed of beryllium oxide. The target section includes a target support member 50 and target 51. The face 52 of the target is formulated of a material such as zirconium, titanium or scandium which will absorb or contains sorbed tritium. Target support member 50 extends into the target chamber 48 through a lower bulkhead member (not shown). The target chamber is formed in addition by cathode member 24 and a glass collar 54 which is held in place by a Kovar or other metallic sleeves 55 and 56. Sleeve 55 is welded to cathode member 24 and sleeve 56 is similarly secured to the bottom support member (not shown). The surface 58 of cathode 24 exposed to the interior of the target chamber converges down to the point at which aperture 40 extends through the cathode member from the ionization chamber to the target chamber. The ratio of the diameter of the aperture 40 to its length (from surface 24a to recessed surface 58) is greater than 0.75 and preferably greater than one in order to provide for efficient extraction of the accelerator gas ions from the ionization chamber and to reduce ion loss by neutralization. In this regard, by making the thickness of the cathode member relatively thin at the location of the aperture the electric field established in the target chamber as described hereinafter tends to extend into the ionization chamber, thus facilitating the extraction of ions and their acceleration toward the target 51. An extraction electrode 60 is interposed between the target surface 52 and the cathode surface 58. The electrode 60 has an aperture 62 therein and the surface 63 facing the cathode surface 58 is projected toward the cathode surface and diverges away from aperture 62. An illustrated in FIG. 2, the electrode surface 63 is of the same general configuration as the cathode surface 58 and is generally parallel therewith. Thus, the slopes of the surfaces 58 and 63 in the direction of the target are substantially the same. The cathode and electrode surfaces tend to concentrate the electric field between the electrode and the cathode along the axis of apertures 40 and 62. A relatively strong field extends from the edge of aperture 40 to the edge of aperture 62. In addition, the field extends into aperture 40 somewhat thus increasing the probability that ions produced in chamber 25 will be extracted and accelerated toward the target surface 52. By shaping the electrode surface 63 so that its slope toward the target is at least as great as the slope of surface 58, the field strength in the peripheral regions of chamber 48 can be maintained at an acceptable level without internal arcing associated with field emission breakdown. In a further embodiment of the invention, the extraction electrode member 60 is shaped such that the slope of surface 63 toward the target is greater than that of surface 58. Thus, in the peripheral regions of the chamber the distance between a point on surface 58 and the corresponding point on surface 63 is greater than the distance between the corresponding surfaces in the central portion of the chamber. This further weakens the electric field in the peripheral portion of the chamber relative to the field through the central portion thereof and, again, reduces the probability of internal arcing and increases the probability that the accelerated ions will impact the target. As noted previously, the diameter of the aperture through the cathode member 24 preferably is greater than the length thereof. Preferably, the wall of electrode 60 is relatively thin so that this same relationship holds for aperture 62. In fact, it is preferred that the diameter of aperture 62 be at least 2 times greater than the length thereof. This relationship substantially lessens the probability that ions accelerated through the target chamber 48 will impact the electrode, thus increasing the bombardment rate on the target. It is further preferred that the diameter of aperture 62 be greater than aperture 40. This relationship provides for ion optics in the target chamber such that the target can be placed in relatively close proximity to the extraction electrode. As noted previously, the extraction electrode 60 is maintained at a slightly lower negative potential than target 52 during production of the neutron burst. For example, the target may be maintained at a potential of -95 KV and the electrode at a potential of -100 KV. The cathode 24 is, of course, positive with respect to the target and extraction electrode and negative with respect to the anode 27. Thus, the cathode 24 may be at chassis ground and the anode during the time that neutrons are produced at a positive voltage of from several hundred to perhaps 3 KV. The negative voltages may be applied to the extraction electrode and target by any suitable means. One suitable technique is to connect the target and extraction electrode in parallel to the same negative voltage source with the resistance in the target circuit being greater than the resistance in the electrode circuit. Thus, when the tube is quiescent the target and electrode are the same negative voltage. However, as accelerator gas ions are produced the resulting current flow through the resistance in the target circuit reduces the voltage at the target by an appropriate amount.
045340528	abstract	The invention provides a block for partially limiting a radiation beam, allowing a first part of this beam to be limited corresponding to a first maximum half angle of opening.. This rectilinearly movable block comprises a cylindrical active surface.. Because of this active surface, said block defines new limits for the beam without modifying the starting orientation of this active surface in dependence on the positions which it may occupy through its rectilinear movement.
047073250	claims	1. A gauge plate for use in customizing replacement upper core plate inserts of a nuclear reactor of the type including a pressure vessel, a core barrel disposed within the pressure vessel, a lower internal structure disposed in the core barrel and including a baffle plate arrangement, and an upper internals structural package having an upper core plate at its lower end, with the upper core palte being provided with a plurality of peripheral grooves which each contain an insert machined to close tolerances for engaging respective approximately rectangular shaped guide pins extending radially inwardly from the inner surface of the core barrel for aligning the upper internals structural package relative to the lower internal structure, said gauge plate comprising: a circular metal plate of a known diameter corresponding substantially to that of the upper core plate of the nuclear reactor to be gauged; a plurality of U-shaped gauging slots formed in the peripheral surface of said gauge plate and extending between its major surfaces, said gauging slots being formed at locations corresponding to the respective locations of the radially inwardly directed guide pins of the reactor to be gauged and being of a known size sufficient to receive the respective guide pins with clearance on all sides; first means for positioning said gauge plate within the nuclear reactor vessel to be gauged, while it contains a baffle plate arrangement but not the upper internals structural package, at the normal elevation of the upper core plate inserts and the guide pins; second means, disposed on said gauge plate, for positioning said gauge plate relative to the baffle plate arrangement of the reactor to be gauged; gauge means in said gauge plate for determining the actual position of the gauge plate relative to the baffle plate arrangement; and remotely controlled measuring means, disposed on said gauge plate, for measuring the clearances between each of said U-shaped gauging slots and the adjacent surfaces of a respective guide pin and the clearance between the peripheral surface of said gauge plate and the inner surface of the core barrel adjacent each said gauging slot, and for providing an indication of the measured clearances at a remote location. positioning the gauge plate in the core barrel of a nuclear reactor vessel containing a baffle plate arrangement but with the upper internals structural package removed, so that the gauge plate rests on the upper end of the baffle plate arrangement with the guide pins of the reactor vessel extending into the respective guaging slots of the gauge plate and with the positioning pins of the guage plats being properly positioned relative to the baffle plate arrangement; at each of said gauging slots and with the gauge plate in the same position, (a) measuring the difference between the peripheral surface of the gauge plate and the inner surface of the reactor core barrel, and (b) measuring the clearance between each of the three sides of the U-shaped gauging slot and the adjacent sides of the associated guide pin; and, with the gauge plate in the same position, determining the actual position of the gauge plate in relation to the baffle plates by inserting gauging means into each of the gauging holes. positioning the gauge plate in the core barrel of a nuclear reactor vessel containing a baffle plate arrangement but with the upper internals structural package removed, so that the gauge plate rests on the upper end of the baffle plate arrangement with the guide pins of the reactor vessel extending into the respective gauging slots of the gauge plate and with the positioning pins of the gauge plate being properly positioned relative to the baffle plate arrangement; successively inserting gauge pins of known different size into one of the gauging holes to determine the largest diameter gauge pin which can be inserted, and then, leaving this largest diameter gauge pin inserted in its respective gauging hole; repeating said steps of successively inserting and leaving for each of the other gauging holes; and thereafter, at each of said gauging slots, (a) measuring the clearance between the peripheral surface of the gauging plate and the inner surface of the reactor core barrel, and (b) measuring the clearance between each of the three sides of the U-shaped gauging slot and the adjacent sides of the associated guide pin. 2. A gauge plate as defined in claim 1 wherein said gauge plate has a thickness substantially less than that of the upper core plate for the reactor. 3. A gauge plate as defined in claim 1 wherein said first means comprises a plurality of support pads disposed on one major surface of said gauge plate and positioned so as to be able to rest on the upper end of the baffle plates of the baffle plate arrangement of the reactor in which said gauge plate is to be used, said support pads being of a thickness so as to position said gauge plate at the elevation of the interface of the upper core plate inserts and the guide pins when said pads are resting on the upper ends of the baffle plates. 4. A gauge plate as defined in claim 3 wherein said second means comprises a plurality of positioning pins extending from said one major surface of said gauge plate, with said positioning pins being located on said gauge plate at respective positions corresponding to the outer most positions of the fuel assembly top nozzles of the reactor, and with each being of a length so that it can extend into the area enclosed by the baffle plate arrangement when said gauge plate is resting on the upper ends of the baffle plates. 5. A gauge plate as defined in claim 4 wherein eight of said positioning pins are provided in four pairs, with two of said pairs of being located along each of the respective cardinal axes of the surface of said gauge plate, with the two said pairs along each cardinal axis being diametrically opposed, and with said positioning pins of each said pair being symmetrically disposed with respect to the associated cardinal axis. 6. A gauge plate as defined in claim 4 wherein said gauging means includes a plurality of gauging holes extending through said gauge plate for receiving gauge pins, with said gauging holes being located at positions corresponding to the expected positions of respective baffle plates of the reactor in which the gauge plate is to be used. 7. A gauge plate as defined in claim 6 wherein said gauging holes are located at positions corresponding to the expected positions of respective baffle plates which cooperate with said positioning pins to position said gauge plate. 8. A gauge plate as defined in claim 6 wherein three of said gauging holes are provided with two of said gauging holes being located at positions corresponding to the positions of two adjacent baffle plates and the third gauging hole being located at a position corresponding to a baffle plate diametrically opposite one of said two adjacent baffle plates. 9. A gauge plate as defined in claim 8 wherein the center line of each of said gauging holes is displaced by a common given dimension from the expected position of the upper edge of the respective baffle plate in a direction perpendicular to the inner surface of the respective baffle plate. 10. A gauge plate as defined in claim 1 wherein said plate includes a plurality of relatively large area openings extending between the major surfaces in the interior portion of said plate. 11. A gauge plate as defined in claim 1 wherein four of said gauging slots are provided with said gauging slots being symmetrically disposed about the circumference of said gauge plate. 12. A gauge plate as defined in claim 1 wherein said measuring means comprises a respective set of four linear measurement devices mounted on the upper major surface of said guage plate adjacent each said U-shaped gauging slot, with three of said measurement devices each being disposed adjacent and perpendicular to a respective one of the three surfaces defining a respective U-shaped gauging slot and the fourth of said measuring devices being adjacent the periphery of said gauge plate and oriented in a radial direction. 13. A method of measuring and providing actual dimensions of the lower internals guide pin locations of a nuclear reactor vessel for use in customizing a replacement upper internals structural package so that it will mate with existing lower internal structure using a gauge plate as defined in claim 6 comprising the steps of: 14. A method as defined in claim 13 wherein the gauge plate includes at least three gauging holes with two of the gauging holes being located at positions corresponding to the positions of two adjacent baffle plates and the third gauging hole being located at a position corresponding to a baffle plate diametrically opposite one of the two adjacent baffle plates, and with the center line of each of the gauging holes being displaced by a common given dimension from the expected position of the upper edge of the respective baffle plate in a direction perpendicular to the inner surface of the respective baffle plate; and wherein said step of determining the actual position of the gauge plate relative to the baffle plates includes inserting gauge pins of known size into the gauging holes until the inner surface of the respective baffle plate is located. 15. A method as defined in claim 14 wherein said step of inserting includes successively inserting gauge pins of known different size into one of the gauge holes to determine the largest diameter gauge pin which can be inserted, and then, with this largest diameter gauge pin inserted in its respective gauge hole, repeating said step of successively inserting for each of the other gauge holes. 16. A method as defined in claim 15 wherein said step of determining the actual position of the gauge plate relative to the baffle plates is carried out before said steps (a) and (b). 17. A method of measuring and providing actual dimensions of the lower internals guide pin locations of a nuclear reactor vessel for use in customizing a replacement upper internals structural package so that it will mate with existing lower internal structure using a gauge plate including: a circular metal plate of a known diameter corresponding substantially to that of the upper core plate of the nuclear reactor to be gauged; a plurality of U-shaped gauging slots formed in the peripheral surface of said gauge plate and extending between its major surfaces, said gauging slots being formed at locations corresponding to the respective locations of the radially inwardly directed guide pins provided on the inner surface of the core barrel of the reactor to be gauged and being of a known size sufficient to receive the respective guide pins with clearance on all sides; a plurality of support pads disposed on one major surface of said gauge plate and positioned so as to be able to rest on the upper end of the baffle plates of the baffle plate arrangement of the reactor in which said gauge plate is to be used, with said support pads being of a thickness so as to position said gauge plate at the normal elevation of the interface of the upper core plate and the guide pins when said pads are resting on the upper ends of the baffle plates; a plurality of positioning pins extending from said one major surface of said gauge plate, with said positioning pins being located on said gauge plate at respective positions corresponding to the outer most positions of the fuel assembly top nozzles of the reactor, and with each being of a length so that it can extend into the area enclosed by the baffle plate arrangement when said gauge plate is resting on the upper ends of the baffle plates; at least three gauging holes extending through said gauge plate for receiving gauge pins, with two of said gauging holes being located at positions corresponding to the expected positions of two adjacent baffle plates and the third gauging hole being located at a position corresponding to a baffle plate diametrically opposite one of said two adjacent baffle plates, and with the center line of each of said gauging holes being displaced by a common given dimension from the expected position of the upper edge of the respective baffle plate in a direction perpendicular to the inner surface of the respective baffle plate; said method comprising the steps of: 18. A method as defined in claim 17 wherein said steps of measuring and said step of inserting are controlled and carried out from a remote location.
	abstract	An integrated passive cooling containment structure for a nuclear reactor includes a concentric arrangement of an inner steel cylindrical shell and an outer steel cylindrical shell that define both a lateral boundary of a containment environment of the nuclear reactor that is configured to accommodate a nuclear reactor and an annular gap space between the inner and outer steel cylindrical shells, a concrete donut structure at a bottom of the annular gap space, and a plurality of concrete columns spaced apart azimuthally around a circumference of the annular gap and extending in parallel from a top surface of the concrete donut structure to a top of the annular gap space. The outer and inner steel cylindrical shells and the concrete donut structure at least partially define one or more coolant channels extending through the annular gap space.
045434883	description	DETAILED DESCRIPTION ON THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic end view of an basket for breeder fuel elements according to the present invention. The basket includes spent fuel receiving steel tubes 1 which are located in apertures 11 formed in a steel plate 2. One or more steel plates 2 may be employed and spaced along the longitudinal axis of the basket to surround the steel tubes 1 at spaced points. The steel tubes 1 and plates 2 form a steel framework about which is cast a metallic material 3 of non-ferrous metal such as aluminum. The slot 4 in the block 3 and the plates 2 serve for orientation of the basket within the cavity of a container (not shown). The centering pins 5 are necessary if the basket is assembled with two or more plates 2 to align the apertures 11 in the several plates. FIG. 2 shows another embodiment in end view where the basket has tubular inserts 7 which are square in cross-section and which are made of steel. On the left-hand side of FIG. 2, the size of the inserts 7 is shown as such that seventeen steel inserts for spent boiling water fuel elements can be placed within a cast circular mass or block 9 whereas on the right-hand side, the size of larger steel inserts 7 is shown as such that seven can be provided for receiving spent pressure water fuel elements. Between the square steel inserts 7, B.sub.4 C plates 8 are inserted as neutron absorbers in the block 9 which is, again, a non-ferrous metallic material or alloy such as aluminum, copper or alloys of these metals. The spent fuel is inserted into the interior 10 of the inserts 7. FIG. 3 shows a schematically a cross-section side view of the basket of FIG. 1 according to the present invention. The basket includes the steel tubes 1 and the steel plates 2 which align the tubes 1. The steel framework consisting of steel tubes 1 and plates 2 is cast about with a metallic material 3 of non-ferrous material as aluminum. The slot 4 is necessary to orientate the basket within the cavity of a container. The centering pins 5 serve for alignment of the apertures 11 if the basket is assembled with two or more plates 2 which are stacked over each other.
055704689	description	DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, numeral 4 indicates a washing device, which includes a spray device 1 for ejecting liquid, a solvent filtering device 2, and a chelate liquid filtering device 3. The spray device 1, which is not shown in detail in the drawing, comprises a pipe provided with a multitude of nozzles. As shown in FIGS. 3 and 4, the washing device 4 comprises a frame 15, to which is provided a main vessel 18 having an opening 16 and a lid 17. A decontamination vessel 22 is rotatably arranged in the main vessel 18. Numeral 19 indicates a multitude of pores formed in the decontamination vessel 22. As shown in FIGS. 5 and 6, the decontamination vessel 22 is formed as a cylindrical body formed of wedge wires 25, which are supported by support bars 26 such that slits are defined between these wedge wires. These slits constitute the pores 19. Thus, in this invention, the term "pores" includes "slits". Numeral 28 indicates an end plate. Numeral 20 indicates an opening, and numeral 21 indicates an opening/closing cover having a multitude of pores 19 like the decontamination vessel 22. The pores 19 have a width or size that is smaller than that of the shot blasting grit. Referring to FIG. 4, numeral 29 indicates rotating members, which consist, for example, of racing rollers. These rotating members support decontamination vessel 22. The decontamination vessel 22 is driven by a driving device 23. Further, the decontamination vessel 22 has a suspension lug 30, by means of which the decontamination vessel 22 can be suspended from an overhead travelling hoist (not shown) so that it can be moved to another main vessel 18 (not shown). Referring to FIG. 1, numeral 5 indicates a solvent supply device, which comprises a solvent vessel 31 containing, for example, methylene chloride, and a first pump 32. The solvent is circulated by way of the spray device 1 and the solvent filtering device 2. Numeral 6 indicates a solvent purifying device which purifies the solvent by heating, vaporizing, and cooling. The solvent purifying device 6 has a second pump 33 and is connected to a rinse solvent supply device 7 comprising rinse solvent vessel 34 for rinsing and a third pump 35. Numeral 36 indicates a fourth pump. Numeral 8 indicates a chelate liquid supply device, which circulates the chelate liquid by way of a chelate liquid vessel 37, a fifth pump 38, the spray device 1, and the chelate liquid filtering device 3, and, then, back to the chelate liquid vessel 37. Numeral 10 indicates an electrolytic processing device for electrolyzing the chelate liquid which contains metal ions. In the electrolytic processing device 10, the chelate liquid is electrolyzed to thereby lose its chelating property. In a precipitating device 11, a precipitant is added to the chelate liquid which has lost its chelating property, thereby generating floes in the liquid. These flocs are removed by filtering the liquid by a filtering device Examples of the precipitant include sodium hydroxide, aqueous ammonia, potassium hexacyanoferrate, and high-molecular coagulant. The water generated in the filtering device 9 is supplied to an ion exchange device 39, where it becomes clean water. A chelating agent is added to the clean water in a chelating agent supply device 12 and the resulting solution is supplied to the chelate liquid vessel 37 again. Numerals 38, 40, and 42 indicate fifth, sixth. seventh and eighth pumps, respectively. The clean water generated in the ion exchange device 39 may be discharged. In FIG. 1, numeral 55 indicates a storage vessel, and, in FIG. 2, numeral 56 indicates an oscillating sieve for removing foreign matter from the grit. Numeral 13 indicates a hot air generator, which comprises a heater 43 and a compressed air generator 44 and supplies hot air to the main vessel 18. Referring to FIG. 7, numeral 46 indicates an apparatus for inspecting substances contaminated with radioactivity, mainly used to inspect shot blast radioactivity and also available for inspection of other objects, for example, machine parts. Numeral 47 indicates a belt conveyor, which is made to intermittently run in the direction indicated by the arrow A47. Numeral 48 indicates a scintillation counter, which is formed as an elongated, band-like component extending perpendicular to the belt conveyor 47 so as to cover the entire width of the conveyor 47. The scintillation counter 48 is connected to a computerized control unit 49, which has a memory bank and is connected to a change-direction device 50 provided on the belt conveyor 47. Numeral 51 indicates a hopper. Numeral 52 indicates a defective-item receiver, and numeral 53 indicates a non-defective-item receiver. The shot blasting grit fed from the hopper 51 is intermittently moved in the direction of the arrow A47 by the belt conveyor 47, and is inspected for radioactivity, block by block each movement. A block in which radioactivity has been detected is memorized in the computerized control unit 49, and is removed by being changed in direction by the change-direction device 50 upon reaching the same. In this way, shot blasting grit free from radioactivity is collected. The operation of the apparatus of this invention will now be described. First, grit contaminated with radioactivity and a polishing-cleaning material are fed into the decontamination vessel 22. An example of the polishing-cleaning material is a ceramic material. Then, the opening 20 is closed, and the opening 16 of the main vessel 18 is also closed. The decontamination vessel 22 is then rotated, and methylene chloride is ejected from the spray device 1, with the gas collecting device 14 being actuated. The grit is washed by the methylene chloride, and any radioactive paint or the like coexisting with the grit is removed therefrom, thereby decontaminating the grit. Such contaminated paint or the like is removed through filtration by the solvent filtering device 2. Next, this methylene chloride is drained from the main vessel 18, and the grit is dried by hot air supplied from the hot air generator 13. Subsequently, chelate liquid, supplied from the chelate liquid supply device 8, is ejected from the spray device 1, and the decontamination vessel 22 is rotated. The chelate liquid removes the radioactive metal ions in the grit, and is filtered by the chelate liquid filtering vessel before it returns to the chelate liquid vessel 37 to be circulated for decontamination. The chelate liquid is then electrolyzed by the electrolytic processing device 10 to thereby lose its chelating property. Then a precipitant is added to the chelate liquid, thereby forming floes in the liquid. These floes are removed by filtering the liquid by the filtering device 9. Then, the liquid is turned into clean water by the ion exchange device 39, supplied with fresh chelating agent from the chelating agent supply device 12 to be regenerated, and then returned to the chelate liquid supply device 8. Part of the methylene chloride is transferred from the solvent vessel 31 to the solvent purifying device 6, where it is heated to be gasified and then cooled to be liquefied, whereby the methylene chloride is purified, and thereafter transferred to the rinse solvent vessel 34. Next, the chelate liquid is drained from the main vessel 18, and hot air is supplied from the hot air generator for drying of the grit. The temperature of this hot air is 70.degree. C., which is much higher than the boiling point of methylene chloride. Accordingly, the temperature of the grit is raised to approximately 70.degree. C. However, even after the above draining, some chelate liquid still remains in the grit, so that the drying process takes time and is difficultto perform. In this condition, a rinse solvent consisting of methylene chloride is supplied. This rinse solvent is then rapidly vaporized, and, by the force of this vaporization, the remaining chelate liquid is separated from the grit. The liquid is then brought to the filtering device 2 by the subsequently fed rinse solvent, and is filtered by the filtering device 2 before it is recovered. The rinse solvent containing the chelate liquid is separated therefrom by an oil water separator 46, which effects separation through difference in specific weight, and is recovered in the solvent vessel 31. The grit in the main vessel 18 has been heated, so that the remaining methylene chloride is immediately vaporized to effect drying of the grit, with the result that the removal of the chelate liquid takes place quickly. Advantages of the method of this invention will now be described. In the method of this invention, constructed as described above, the chelate liquid containing contaminated metal ions and remaining on the substance contaminated with radioactivity and adhering thereto, is separated from the contaminated substance by a rapid vaporization of the solvent, and then drained along with the subsequently supplied solvent, thereby effectively decontaminating the substance. Further, the draining of the solvent immediately results in a dried state, so that the bothersome operation of removing the remaining chelate liquid by drying process can be eliminated. This can be achieved very effectively when the solvent is methylene chloride. When the contaminated substance is shot blasting grit, which consists of fine particles, it is possible to quickly and effectively perform the difficult operations of separating and removing the remaining and adhering chelate liquid. Next, advantages of the apparatus of this invention will be described. In the apparatus of this invention, constructed as described above, a single apparatus can perform all of the following processes: decontamination using a solvent, decontamination using a chelate liquid, rinsing using the solvent, in which rapid separation and removal of remaining chelate liquid is effected, drying of the grit, and so on. The chelate liquid is electrolyzed by an electrolytic device, and in the precipitating device a precipitant is supplied to the chelate liquid which has lost its chelating property by the electrolysis, thereby forming flocs in the liquid. These floes are removed by filtering the liquid by the filtering device. Then, the liquid is turned into clean water by the ion exchange device. By supplying some chelating agent to this clean water, the liquid can be recycled. Thus, a single apparatus can perform all of the decontamination processes. Accordingly, the installation space for the apparatus can be reduced. Further, there is no need to provide complicated devices for moving the contaminated substance between a number of decontaminating apparatuses, nor is it necessary to perform the bothersome operation of moving the contaminated substance from one apparatus to another. In addition, since the pores 19 of the decontamination vessel 22 have a size or width which is smaller than that of the grit, it is possible for the grit to be decontaminated effectively. Further, since the decontamination vessel 22 has a polishing-cleaning material, polishing and cleaning can be conducted simultaneously with the so-called running-liquid washing using the solvent and the chelate liquid, thereby conducting decontamination effectively. Further, in an aspect of the invention where the decontamination vessel 22 is detachably formed with respect to the main vessel 18, and a plurality of main vessels 18 and a plurality of decontamination vessels 22 are formed, it is possible to separately conduct a process requiring a long time and that requiring a relatively short time, thereby achieving an improvement in operational efficiency.
	claims	1. A nuclear reactor fuel assembly for an operating reactor nuclear core comprising:a channel having a wall;a fuel bundle including full length fuel rods, tie rods and at least water rod, wherein the wall extends around the perimeter of the fuel bundle,an upper end plug on an upper end of each of the full length fuel rods, the tie rods and the at least one water rod;an upper tie plate within the wall of the channel including a planar network of interconnected ribs and first pin support apertures, wherein the first pin support apertures are adapted to receive the upper end plugs and the planar network includes open regions between the ribs and the first pin support apertures, anda debris shield including a porous region at least coextensive with the planar network, wherein the porous region includes second pin support apertures, the second pin support apertures are each coaxial with one first pin support apertures, and pores in the porous region are individually smaller than each of the second pin support apertures, andwherein the debris shield is adjacent the planar network and is above the full length fuel rods, the tie rods and the at least one water rod. 2. The nuclear reactor fuel assembly in claim 1 wherein the porous region extends at least to the wall of the channel. 3. The nuclear reactor fuel assembly in claim 1 wherein the debris shield includes a flat panel section at least coextensive with the planar network of the upper tie plate.
	abstract	A radiation-monitoring diagnostic hodoscope system for producing an approximate image of radiation-detecting components within or external to a pressure vessel of an operating, damaged, or shutdown nuclear-power plant.
	claims	1. A rotatable contamination barrier for use with an EUV radiation system, the barrier comprising:a blade structure configured to trap contaminant material coming from a radiation source;a bearing structure, coupled to a static frame, configured to rotatably bear the blade structure; andan eccentric mass element displaced relative to a central axis of rotation to balance the blade structure in the bearing structure. 2. The barrier of claim 1, wherein a plurality of eccentric mass elements are provided in at least two planes displaced laterally along the central axis of rotation. 3. The barrier of claim 1, wherein the eccentric mass element is displaceable relative to the central axis of rotation. 4. The barrier of claim 3, further comprising:a imbalance sensor configured to provide a signal of a sensed imbalance of the contamination barrier in the bearing structure; andan adjustment unit configured to automatically adjust the eccentric mass element in response to the signal. 5. The barrier of claim 4, wherein the imbalance sensor unit is configured to measure an eccentric displacement of the blade structure in a lateral plane that is the same as or parallel to the lateral plane wherein the eccentric mass element is provided. 6. The barrier of claim 1, wherein the bearing structure is configured to be operated in a vacuum environment and comprises a gas bearing. 7. The barrier of claim 1, wherein the blade structure comprises a rotatable shaft and a plurality of closely packed blades mounted to the rotatable shaft, the blades radially oriented relative to the rotatable shaft. 8. The barrier of claim 7, wherein the eccentric mass element comprises an addition of mass to the rotatable shaft, a shift of mass on or in the rotatable shaft, removal of mass from the rotatable shaft, or any combination of the foregoing. 9. The barrier of claim 7, wherein the rotatable shaft is thermally stabilized against thermal energy imparted on the plurality of blades by EUV radiation and/or debris. 10. The barrier of claim 9, wherein the rotating shaft comprises a thermally stabilizing coupling element configured to couple a shaft part that is borne in the bearing structure and a shaft part that provides a mount to the blade structure. 11. The barrier of claim 10, wherein the shaft part borne in the bearing structure comprises an alloy comprising molybdenum and wherein the coupling element is comprised of an alloy comprising tantalum. 12. A balancing unit to balance a rotatable contamination barrier, the unit comprising:a bearing structure configured to bear a blade structure of the rotatable contamination barrier;a imbalance sensor unit configured to provide a signal of a sensed imbalance of the blade structure in the bearing structure during rotation of the blade structure; anda calculating unit configured to calculate a location to provide one or more eccentric mass elements on or to the blade structure and the amount of such mass, the calculating unit communicatively coupled to the imbalance sensor. 13. The balancing unit of claim 12, wherein the calculating unit is configured to calculate a location of the one or more eccentric mass elements in a lateral plane that is the same as or parallel to a lateral plane wherein the imbalance sensor unit senses the imbalance. 14. The balancing unit of claim 13, wherein the bearing structure is configured to be mounted in a vacuum environment and comprises a gas bearing. 15. The balancing unit of claim 12, wherein the imbalance sensor unit comprises a plurality of force sensors configured to measure a force exerted on the bearing structure by the blade structure when rotating. 16. A method of balancing a rotatable contamination barrier for use in an EUV radiation system, comprising:bearing a blade structure in a bearing structure provided in a vacuum environment;sensing an imbalance of the blade structure in the bearing structure during rotation of the blade structure; andcalculating, based on the sensed imbalance, a location to provide an eccentric mass element on or to the blade structure and an amount of such mass. 17. The method of claim 16, further comprising:providing the blade structure with an eccentric mass element to balance the blade structure in the bearing structure; andautomatically adjusting the eccentric mass element in response to the imbalance signal. 18. A method of cleaning a rotatable contamination barrier for use with an EUV radiation system, comprising:adjusting an eccentric mass element of the contamination barrier to provide an imbalance; androtating the contamination barrier with the imbalance to shake clean the contamination barrier. 19. A lithographic apparatus, comprising:a rotatable contamination barrier configured to receive a beam of radiation, the contamination barrier comprising a blade structure configured to trap contaminant material coming from a radiation source, a bearing structure, coupled to a static frame, configured to rotatably bear the blade structure, and an eccentric mass element displaced relative to a central axis of rotation to balance the blade structure in the bearing structure;an illumination system configured to condition the radiation beam;a support constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam;a substrate table constructed to hold a substrate; anda projection system configured to project the patterned radiation beam onto a target portion of the substrate.
052290654	claims	1. Method for measuring the temperature of the primary coolant fluid of a nuclear reactor comprising a pressure vessel in which is arranged the core of the reactor and a primary circuit having at least one loop on which is arranged a steam generator, and which comprises pipes (16, 55) in which the primary coolant fluid of the reactor circulates, one of said pipes being a hot leg (16), another of said pipes being a cold leg (55), connecting the pressure vessel to the steam generator, and another pipe, or the cold leg (55), ensuring the return of the coolant fluid coming from the steam generator into the pressure vessel, said method comprising the steps of (a) sampling coolant fluid from a substantially horizontal part of the hot leg (16) at at least three points (19, 20, 21) distributed at the periphery of a straight section of the hot leg (16), in such a way that at least one of the sampling points (20, 21), or lower sampling point, is situated beneath the axis (17) of the hot leg (16); (b) measuring the temperature of the coolant water sampled at each of the sampling points (19, 20, 21) at its outlet from the hot leg (16); and (c) reintroducing the coolant fluid into the hot leg (16) at a point (22) situated in a position substantially diametrically opposite one of the lower sampling points (20, 21), on the straight section of the hot leg (16). (a) at least three devices for sampling coolant fluid, traversing the wall of a substantially horizontal part of the hot leg (16) and distributed at the periphery of a straight section of said hot leg so that at least one of the sampling devices (20, 21) is situated beneath the axis (17) of the hot leg (16); and (b) an element (22) for reintroducing coolant fluid into the hot leg (16), arranged in a position substantially diametrically opposite one of the sampling devices situated beneath the axis (17) of the hot leg (16) and pipes (24, 25, 26) connecting each of the sampling devices (19, 20, 21) to the reintroduction element (22). 2. Method according to claim 1, wherein the coolant fluid is sampled at three points (19, 20, 21) arranged at 120.degree. to one another about the axis (17) of the hot leg (16), in a straight section of said hot leg (16). 3. Method according to claim 1, wherein the temperature of the coolant fluid is measured at a point (56) situated in the vicinity of the upper part of the cold leg (55) of the primary circuit. 4. Method according to claim 1, wherein the mean of the temperatures measured at each of the sampling points (19, 20, 21) of the hot leg (16) is calculated by electronic means. 5. Method according to claim 1, wherein the temperature of the coolant water reintroduced into the hot leg (16) is measured at the point situated in a position substantially diametrically opposite one of the lower sampling points (20, 21), and the temperature of the coolant water reintroduced at the reintroduction point (22) is compared with the mean of the temperatures measured at said three sampling points (19, 20, 21). 6. Device for measuring the temperature of the primary coolant fluid of a nuclear reactor comprising a pressure vessel in which is arranged the core of the reactor and a primary circuit having at least one loop on which is arranged a steam generator, and which comprises pipes (16, 55) in which the primary coolant fluid of the reactor circulates, one of said pipes being a hot leg (16), connecting the pressure vessel to the steam generator, and another of said pipes being a cold leg (55), ensuring the return of the coolant fluid coming from the steam generator into the pressure vessel, said device comprising 7. Device according to claim 6, wherein each of the sampling devices (19, 20, 21) is in the form of a scoop comprising a part in the form of a glove finger fixed in an opening (28) traversing the wall of the hot leg (16) and having, in its part situated inside the hot leg (16), openings (31) traversing its wall and opening out into a central channel (32), and a projection (34) comprising an internal bore (36) communicating with the central channel (32) of the part in the form of a glove finger, in which projection is fixed a temperature-measuring probe (39) carried by a support (38) ensuring the sealed closure of the bore of the projection (34) fixed to the outer surface of the hot leg (16), said projection comprising a channel (41) opening out into its bore (36) and brought into communication with a pipe (24) connected at its other end to the reintroduction element (22). 8. Device according to claim 6 or 7, wherein the reintroduction element (22) consists of a projection (46) fixed to the outer surface of the hot leg (16) in the region of an opening (45) traversing the wall of the hot leg (16) and comprising a bore (48) communicating with the opening (45) in which is fixed a temperature probe (51) on a support (50) ensuring the sealed closure, towards the outside, of the bore (48) of the projection (46), said projection (46) comprising at least three radial channels (52) opening out into the bore (48) of the projection (46), each of said channels communicating with a pipe (24, 25, 26) connected to a sampling device (19, 20, 21). 9. Device according to claim 8, wherein the support (50) arranged in the bore (48) of the projection (46) of the reintroduction element (22) is replaced by a plug closing the bore (48) of the projection (46). 10. Device according to claim 7, wherein the reintroduction element (22) consists of a projection (46) fixed to the outer surface of the hot leg (16) in the region of an opening (45) traversing the wall of the hot leg (16) and comprising a bore (48) communicating with the opening (45) in which is fixed a temperature probe (51) on a support (50) ensuring the sealed closure, towards the outside, of the bore (48) of the projection (46), the projection (46) furthermore comprising at least three channels (51) of radial direction opening out into the bore (48) of the projection (46), each communicating with a pipe (24, 25, 26) connected to a sampling device (19, 20, 21).
	abstract	A shielding grid constructed of a radiation absorbing material for use with an array of discreet, non contiguous radiation sensors to protect such sensors from scattered radiation. The sensors each have a radiation sensitive area with a width and a length. In designing the grid a prototile having a prototile width and a prototile length is developed. The prototile width is equal to the radiation sensitive area width divided by an integer and the prototile length is also equal to the radiation sensitive area length divided by a integer. The prototile contains a motif contained solely within the prototile that forms a pattern when a plurality of prototiles sufficient to cover the array of discreet sensor are arrayed contiguously. The grid is constructed with the radiation absorbing material in this pattern.
	abstract	Disclosed is a scanning device using radiation beam for backscatter imaging. The scanning device includes a radiation source; a stationary shield plate and a rotary shield body positioned respectively between the radiation source and the subject to be scanned, wherein the stationary shield plate is fixed relative to the radiation source, and the rotary shield body is rotatable relative to the stationary shield plate. The ray passing area permitting the rays from the radiation source to pass through the stationary shield plate is provided on the stationary shield plate, and ray incidence area and ray exit area are respectively provided on the rotary shield body. During the process of the rotating and scanning of the rotary shield body, the ray passing area of the stationary shield plate intersects consecutively with the ray incidence area and the ray exit area of the rotary shield body to form scanning collimation holes. Further, a scanning method using radiation beam for backscatter imaging is also provided.
	claims	1. A radiation inspection system, comprising:a radiation source for emitting an initial beam and a beam modulating device for modulating the initial beam into a scanning beam, wherein the beam modulating device comprises a first collimating structure disposed at a beam exit side of the radiation source and a second collimating structure disposed at a beam exit side of the first collimating structure, the first collimating structure comprises a first collimating port, the second collimating structure comprises a second collimating port, the second collimating structure is movable relative to the first collimating structure to change a relative position of the first collimating port with the second collimating port, wherein the beam modulating device is shifted between a first operational state in which the beam modulating device modulates the initial beam into a fan beam, and a second operational state in which the beam modulating device modulates the initial beam into a pencil beam variable in position. 2. The radiation inspection system according to claim 1, wherein in the second operational state, the second collimating structure is translatable and/or rotatable relative to the first collimating structure to change an intersecting position of the second collimating port and the first collimating port in a direction perpendicular to an exit direction of the initial beam, thereby changing a position of the pencil beam. 3. The beam modulating device according to claim 1, wherein the first collimating structure comprises a first collimating plate; and the second collimating structure comprises a second collimating plate. 4. The radiation inspection system according to claim 3, wherein the first collimating plate is a first flat collimating plate, and the second collimating plate is a second collimating flat plate; or, the first collimating plate is a first collimating curved plate, and the second collimating plate is a second collimating curved plate. 5. The radiation inspection system according to claim 3, wherein the first collimating plate is parallel to the second collimating plate. 6. The radiation inspection system according to claim 1, wherein the first collimating port is a first collimating slit; and the second collimating port is a second collimating slit. 7. The radiation inspection system according to claim 1, wherein at least one of the first collimating slit and the second collimating slit is a straight-linear collimating slit. 8. The radiation inspection system according to claim 7, wherein the second collimating slit is disposed obliquely or vertically with respect to the first collimating slit. 9. The radiation inspection system according to claim 1, wherein:the first collimating structure is stationary, and the second collimating structure is movably disposed; or,the first collimating structure is movably disposed, and the second collimating structure is stationary; orthe first collimating structure and the second collimating structure are movably disposed. 10. The radiation inspection system according to claim 1, wherein the radiation source comprises a neutron source. 11. The radiation inspection system according to claim 10, wherein the neutron source comprises a photoneutron source. 12. The radiation inspection system according to claim 10, wherein the radiation inspection system further comprises a neutron modulating mask, which is disposed on the periphery of the neutron source, to modulate neutrons generated by the neutron source. 13. The radiation inspection system according to claim 12, wherein the neutron modulating mask comprises a moderating layer, which is disposed at the periphery of the neutron source to moderate the neutrons produced by the neutron source. 14. The radiation inspection system according to claim 13, wherein the neutron modulating mask comprises a shielding layer, shielding layer is disposed at the periphery of the moderating layer and comprises a shielding portion that shields the moderated neutrons and a neutron exit port that is disposed on the beam exit side for emitting the initial beam. 15. The radiation inspection system according to claim 1, comprising a detection device and a controller, wherein the detection device is configured to receive photons scattered by an inspected object radiated by the scanning beam, and the controller is coupled to the detection device to receive a detection signal from the detection device and form an inspection result according to the detection signal. 16. The radiation inspection system according to claim 15, wherein the detection device comprises a first detecting module and a second detecting module having an energy resolution higher than the first detecting module, wherein the first detecting module and the second detecting module are configured to receive the photons scattered by the inspected object radiated by the scanning beam; the controller is coupled to the first detecting module to receive a first detection signal from the first detecting module and form a first inspection result according to the first detection signal; the controller is also coupled to the second detecting module to receive a second detection signal from the second detecting module and to form a second inspection result according to the second detection signal. 17. The radiation inspection system according to claim 16, wherein the detection device comprises a first detecting module foreground collimating structure for forming a beam shape of the photons entering the first detecting module; and/or the detection device comprises a second detecting module foreground collimating structure for forming a beam shape of the photons entering the second detecting module. 18. The radiation inspection system according to claim 16, wherein in the second operational state, the second detecting module is fixed in position with respect to the pencil beam in a detecting process. 19. A radiation inspection method, for inspecting an inspected subject by using the radiation inspection system according to claim 1, comprising:placing the beam modulating device in a first operational state, and scanning the inspected subject by using the fan beam to determine a suspected area to be accurately inspected; andplacing the beam modulating device in a second operational state, and accurately scanning the suspected area by using the pencil beam. 20. The radiation inspection method according to claim 19, wherein the radiation inspection system comprises a first detecting module and a second detection having an energy resolution higher than the first detecting module, and the radiation inspection method comprises:in the first operational state, the first detecting module detects separately, or the first detecting module and the second detecting module detect simultaneously to determine the suspected area;in the second operational state, the second detecting module detects separately, or the first detecting module and the second detecting module detect simultaneously to accurately inspect the suspected area.
046541837	claims	1. A process for selective neutralization of H.sup.- ions in a magnetic field to produce an intense negative hydrogen ion beam with spin polarized protons, comprising the steps of: providing a multi-ampere beam of H.sup.- ions; providing a beam of laser light, any photon of which has sufficient energy to photodetach one electron from any one of the H.sup.- ions; providing a uniform solenoidal magnetic field around a portion of the length of said beam of H.sup.- ions to effectively spin polarize the H.sup.- ions in said beam, thereby to produce a first group of ions with proton spin aligned with said magnetic field and to produce a second group of ions with proton spin opposed to said magnetic field; directing said beam of laser light through the spin polarized beam of H.sup.- ions to selectively neutralize the majority of the ions in one of said groups, without neutralizing the ions in the other group; separating said one group of ions from said other group of ions, and directing said other group of ions in an intense H.sup.- ion beam toward a predetermined objective. 2. A process as defined in claim 1 wherein said beam of laser light is produced by a 1135 .ANG. laser whose photodetachment products are a free electron and an H.sup.o atom excited in the n=2 level. 3. A process as defined in claim 1 wherein said beam of laser light is produced by a 32,000 .ANG. laser. 4. A process as defined in claim 1 wherein said beam of laser light is produced by a laser operating in the range 1135 .ANG. to 32,000 .ANG.. 5. A process as defined in claim 4 wherein said magnetic field is below 10.sup.8 Gauss and said beam of laser light is produced by either a 1135 .ANG. laser or by a 16,000 .ANG. laser. 6. A process as defined in claim 5 wherein said beam of laser light is positioned transverse to, and in intersecting relationship with, said spin polarized beam of H.sup.- ions. 7. A process as defined in claim 5 wherein said beam of laser light is positioned substantially co-linearly with said spin polarized beam of H.sup.- ions. 8. A process as defined in claim 6 wherein the first group of ions is neutralized, and wherein the second group of ions is separated from the first group of ions and formed into an intense beam of H.sup.- ions. 9. A process as defined in claim 8 wherein said second group of ions is separated from the first group of ions by curving the longitudinal axis of said magnetic field, thereby to bend said intense beam of H.sup.- ions in a path that diverts said second group of ions away from the neutralized ions in the first group. 10. A process as defined in claim 8 wherein said intense beam of H.sup.- ions is a multi-ampere beam. 11. A process as defined in claim 5 wherein said magnetic field is at least 100 Gauss and is sufficiently strong to result in Zeeman hyperfine splitting of the H.sup.- ion beam into two populations or groups of ions whose neutralization energy is solely dependent, respectively, on the selective polarization of their respective nuclei in said H.sup.- ion beam.
	claims	1. A method of resetting a substrate processing apparatus having a chamber, the method comprising:an evacuating step of evacuating the chamber;a temperature setting step of setting a temperature in the chamber;an abnormality judgment step of judging whether or not there is an abnormality in the chamber;a seasoning step of stabilizing an atmosphere in the chamber so as to conform to predetermined processing conditions; anda displaying step of displaying results judged in said abnormality judgment step,wherein:said abnormality judgment step comprises measuring at least one selected from data that change in response to a change in a state inside the chamber, and comparing the measured data with reference data that corresponds to the measured data for a normal state in the chamber; andin said temperature setting step, the temperature in the chamber is set to a temperature different from a temperature in the chamber during ordinary substrate processing. 2. A method as claimed in claim 1, wherein in said abnormality judgment step, a processing gas that does not cause production of a reaction product in the chamber is introduced while a substrate in the chamber is subjected to a predetermined process. 3. A method as claimed in claim 2, wherein the processing gas comprises only oxygen. 4. A method as claimed in claim 1, wherein the measured data comprises a log showing a state of at least one component part of the substrate processing apparatus. 5. A method as claimed in claim 4, wherein the log is of an impedance of a matcher that adjusts high-frequency electrical power applied to a lower electrode disposed in the chamber. 6. A method as claimed in claim 4, wherein the log is of a voltage between a lower electrode disposed in the chamber and a matcher that adjusts high-frequency electrical power applied to the lower electrode. 7. A method as claimed in claim 4, wherein the log is of an opening extent of a control valve that controls a pressure in the chamber. 8. A method as claimed in claim 1, wherein the measured data is processed substrate light emission data. 9. A method as claimed in claim 8, wherein the light emission data relates to a light intensity ratio. 10. A method as claimed in claim 1, wherein the measured data is data relating to a high-frequency power source that supplies high-frequency electrical power applied to a lower electrode disposed in the chamber. 11. A method as claimed in claim 1, wherein in said evacuating step, the temperature in the chamber is raised. 12. A method as claimed in claim 1, wherein in said seasoning step, stability of the atmosphere in the chamber is detected based on a difference in light emission data between two consecutively processed substrates. 13. A method as claimed in claim 12, wherein in said seasoning step, the stability of the atmosphere in the chamber is detected based on a derivative of the difference in the light emission data. 14. A method as claimed in claim 1, wherein in said abnormality judgment step, a leak in the chamber is detected based on a ratio of light emission amounts at different wavelengths for light emission from a processed substrate. 15. A computer-readable storage medium storing a program for causing a computer to implement a method of resetting a substrate processing apparatus having a chamber, the program comprising:an evacuating module for evacuating the chamber;a temperature setting module for setting a temperature in the chamber;an abnormality judgment module for judging whether or not there is an abnormality in the chamber;a seasoning module for stabilizing an atmosphere in the chamber so as to conform to predetermined processing conditions; anda displaying module for displaying results judged by said abnormality judgment module,wherein:said abnormality judgment module measures at least one selected from data that change in response to a change in a state inside the chamber, and compares the measured data with reference data that corresponds to the measured data for a normal state in the chamber; andsaid temperature setting module sets the temperature in the chamber to a temperature different from a temperature in the chamber during ordinary substrate processing. 16. A substrate processing apparatus comprising:a chamber;an evacuating device that evacuates said chamber;a temperature setting device that sets a temperature in said chamber;an abnormality judgment device that judges whether or not there is an abnormality in said chamber;a seasoning device that stabilizes an atmosphere in said chamber so as to conform to predetermined processing conditions; anda displaying device for displaying results judged by said abnormality judgment device,wherein:said abnormality judgment device measures at least one selected from data that change in response to a change in a state inside said chamber, and compares the measured data with reference data that corresponds to the measured data for a normal state in said chamber; andsaid temperature setting device sets the temperature in the chamber to a temperature different from a temperature in the chamber during ordinary substrate processing.
	description	FIG. 1 shows a grating element 1 with a plurality of individual gratings 9 in a beam path of an illumination system. Individual gratings 9 are arranged one after the other in the beam direction. Light from a light source 3 is gathered by a collecting component, a collector 5. Collector 5 in this example is an ellipsoidal mirror, which produces an image of light source 3. A collimated light bundle with an aperture of around NA=0.1 is deflected in grazing incidence by grating element 1 after collector 5 so that an intermediate image of light source 3 comes to lie in or near a diaphragm plane 200 of a physical diaphragm, i.e., diaphragm 7.3. By use of further physical diaphragms, i.e., diaphragms 7.1 and 7.2, arranged in front of diaphragm 7.3, a part of the unwanted radiation can be filtered out in order to reduce the heat load on diaphragm 7.3. Diaphragm 7.3 in one embodiment can have a circular opening. Diaphragm 7.3 is situated in a focal plane of a desired diffraction order, here, the xe2x88x921 order (reference numeral 16). Further diaphragms 7.1, 7.2 can be additionally cooled, which is not depicted. Grating element 1 can also be cooled, for example, by a cooling on its backside. A backside cooling device 8 is preferably a liquid cooling device with an inlet 10.1 and an outlet 10.2. With grating element 1 and diaphragm 7.3, it is possible to totally block the 0th order, which comprises all wavelengths of light source 3 in an illumination system according to the invention. Furthermore, all higher orders except the xe2x88x921 order are also blocked. Discrete grating periods for an arrangement of individual gratings 9 arranged one after the other according to the invention shall now be given below. For the derivation, we shall resort to reflective imaging optics, wherein the optics will image light from a virtual intermediate image, corresponding to the 0th order, in an actual image, corresponding to the +1 or xe2x88x921 order. A solution is then given by a hyperboloid. A grating element designed in a plane must thus have grating grooves, in an ideal case, that are given by points of intersection of a hyperbolic family of curves with this plane, the family of curves being defined by hyperbolas, which have a light path difference of nxcfx80 for a point-to-point image between a focal point without a mirror and the nth order. The inventors have discovered that, under grazing incidence, this grating element with optical effect can be resolved sufficiently well by an array of individual gratings arranged one after the other or above the other, without the imaging quality of the illumination system being unacceptably impaired. Parameters used for a formal derivation of a grating element according to the invention are given in FIG. 2. Here: xcex1i: is the angle at which the light beam impinges on the grating element, xcex1t: is the angle at which the beam is diffracted by the grating element, and h, hxe2x80x2: are the heights of the image loci. A particular beam, which impinges on grating element 1 at the angle xcex1i, is reflected at angle xcex1t in the 0th diffraction order. The first diffraction order for this beam needs to be far enough away that a separation of the diffraction orders is possible taking into consideration the diameter of the image of light source 3 at the focal point. It is then possible, by an arrangement of diaphragm 7.3 in the plane where the focal point comes to lie, to completely block the 0th diffraction order, which comprises all wavelengths. The beam angle of the first diffraction order relative to the grating surface, i.e., angle xcex1t, must be respectively larger or smaller than angle xcex1i by xcex94xcex1, where: Δ ⁢ xe2x80x83 ⁢ α greater than 2 ⁢ arctan ⁡ ( D 21 ) ( 1 ) wherein: D: is the distance of a desired diffraction order from the 0th diffraction order in a filter plane l: is the distance between a locus of reflection on a mirror with grating and an image point. For a central ray, hereinafter termed the chief ray, let an angle of incidence be xcex1i(0). From this, we can determine the heights h and hxe2x80x2 of image loci. Likewise, z-coordinates of the image loci can be calculated relative to a ray intersection point of the chief ray with the mirror: h=l0 sin xcex1i(0)xe2x80x83xe2x80x83(2) hxe2x80x2=l0 sin xcex1t(0)=l0 sin(xcex1i(0)+xcex94xcex1)xe2x80x83xe2x80x83(3) z=l0 cos xcex1i(0)xe2x80x83xe2x80x83(4) zxe2x80x2=l0 cos xcex1t(0)=l0 cos(xcex1i(0)+xcex94xcex1)dz=zxe2x88x92zxe2x80x2xe2x80x83xe2x80x83(5) Now, for every other beam, designated by its angle xcex1i, it is possible to determine a length to the 0th order l(xcex1i) and a length to the 1st order lxe2x80x2(xcex1i), as well as a new z-coordinate zxe2x80x2(xcex1i)=z(xcex1i)xe2x88x92dz, wherein hxe2x80x2(xcex1i)=hxe2x80x2=const. From the quantities lxe2x80x2(xcex1i) and zxe2x80x2(xcex1i), a local diffraction angle xcex1t(xcex1i) is determined as: α t ⁡ ( α i ) = arccos ⁡ ( z xe2x80x2 ⁡ ( α i ) l xe2x80x2 ⁡ ( α i ) ) ( 6 ) and there follows for the local grating period P: P = λ cos ⁢ xe2x80x83 ⁢ α i - cos ⁢ xe2x80x83 ⁢ α i ⁡ ( α i ) ( 7 ) We shall now give two examples of embodiments of grating spectral filters with individual gratings arranged one after the other, with a grating period being different for the individual gratings. An arrangement of the individual gratings in a plane is especially advantageous for cooling the grating, since the grating can be provided with a cooling gradient on its backside, for example, cooling channels. The values for xcex1i, xcex1t, the grating period, a starting value and an ending value along the z-axis, and a Blaze depth of a grating element produced from individual gratings arranged one after the other will be found in Tables 1 and 2. Regarding a definition of the Blaze depth, refer to FIG. 8 in the following description. Table 1 shows an example of an embodiment for 21 linear gratings. Table 2 shows an example of an embodiment for 31 linear gratings. The following parameters are given: The individual gratings are designed as so-called Blaze gratings, i.e., they are optimized for maximum efficiency in the desired diffraction order. This is achieved approximately by a triangular groove profile. An ideal Blaze depth B in a scalar approximation is calculated by B = "LeftBracketingBar" n "RightBracketingBar" ⁢ λ sin ⁢ xe2x80x83 ⁢ α t + sin ⁢ xe2x80x83 ⁢ α i ( 8 ) Table 1: 21 grating segments made from individual gratings, which are arranged one after the other in a plane, together yield a spectral filter. Starting and ending positions of the gratings in terms of a point of incidence of a chief ray with a surface in which the gratings lie are given. Table 2 31 grating segments made from individual gratings, which are arranged one after the other in a plane, together yield a spectral filter. Starting and ending positions of the gratings in terms of a point of incidence of a chief ray with a surface in which the gratings lie are given. FIG. 3 shows a grating period of individual gratings as a function of an angle of incidence xcex1i. The points reflect discrete values of the example of the embodiment with 31 individual gratings according to Table 2. FIGS. 4A and 4B show spot diagrams of a point image of the xe2x88x921 diffraction order for a design wavelength of 13.5 nm in a diaphragm plane, FIG. 4A with 21 and FIG. 4B with 31 individual gratings. The discrete nature of the grating element is made evident by a slight wash-out in the y-direction, but this is negligibly small, especially for N greater than 30 gratings with less than xc2x10.5 mm; the image of the light source is washed out by this amount in the y-direction. The scale indicated in FIGS. 4A and 4B pertains to the scaling in both the x and the y directions. In order to reduce manufacturing expense, in another embodiment of the invention it is proposed to have identically configured grating segments, but to incline these with an angle of tilt so that a desired diffraction order is pointed in a target direction. In this way, in the simplest case, one can put a spectral filter together from an array of identical individual gratings. FIG. 5 shows such a grating element. Grating element 1 comprises a plurality of individual gratings 9 inclined against a plane of incidence E. In order to compute an angle of inclination of an individual grating 9 with a constant grating period, one can use the Laue construction shown in FIGS. 6A and 6B. The reference symbols used hereafter can be found in these drawings. With the known angle xcfx89=180xc2x0xe2x88x92xcex1ixe2x88x92xcex1t="sgr"i+"sgr"txe2x80x83xe2x80x83(9) it follows for the angle of inclination xcex2: xcex2=xcex1i+"sgr"ixe2x88x9290xc2x0xe2x80x83xe2x80x83(10) The angles"sgr"i and"sgr"t are associated by the Laue equation to the grating period P in the following manner: sin ⁢ xe2x80x83 ⁢ σ i - sin ⁢ xe2x80x83 ⁢ σ t = λ P ( 11 ) Solving equation (11) with (9) in terms of"sgr"i yields sin ⁢ xe2x80x83 ⁢ σ i = - b + b 2 - 4 ⁢ ac 2 ⁢ a ( 12 ) wherein: a=2(1+cos xcfx89) b = - 2 ⁢ xe2x80x83 ⁢ λ P ⁢ ( 1 + cos ⁢ xe2x80x83 ⁢ ω ) c = λ 2 P 2 - sin 2 ⁢ ω In this manner, the angles of inclination xcex2 of the individual gratings can be calculated. Table 3 contains an of example an embodiment with 40 individual gratings, the following parameters being given: Table 3: Angles of inclination of the grating element with 40 individual gratings. Grating period: 1.5007 xcexcm FIG. 6C shows the inclination angle xcex2 of the individual gratings as a function of the angle of incidence xcex1i. The points reflect the discrete points of the example of embodiment with 40 individual gratings according to Table 3. FIG. 7 shows a spot diagram of a point image of the xe2x88x921 diffraction order in the diaphragm plane. The discrete nature of the grating element is made evident by a slight washout in the y-direction, but this is negligibly small with xe2x89xa6xc2x10.5 mm; the image of the light source is washed out by this amount in the y-direction. The scale indicated in FIG. 7 pertains to the scaling both in the x and the y directions. With the grating spectral filters according to the examples of embodiment in Table 1, Table 2 and Table 3, wavelengths greater than approximately 17 nm can be almost totally filtered out. Wavelengths less than this are only partly filtered. By the invention the heat load on the mirrors of a projection system can be clearly reduced. As an alternative to an arrangement of individual gratings 9 in a plane or tilted next to each other, they can also be arranged one above the other. An arrangement of one above the other yields a grating spectral filter 1, as shown in FIG. 9. The individual gratings of the individual planes are designated 9.1 and 9.2. The same components as in the embodiment according to FIG. 1 are given the same reference numbers. The gratings arranged one above the other can have a different grating period or can be tilted relative to each other. In order to obtain a grating element 1 with optimal diffraction efficiency, each individual grating of the grating element is preferably designed as a Blaze grating. FIG. 8 shows a Blaze grating with approximately triangular groove profile. Reference 11 designates a ray impinging on grating 9, designed as a Blaze grating, with a grating period P; 12 designates a ray reflected on the grating 9 in the 0th order and 16 designates a ray diffracted in the xe2x88x921 order. Since the Blaze depth according to equation (8) is dependent on an angle of incidence of the beams impinging onto the grating 9, in an ideal case, each individual grating 9 of the grating element will have a different Blaze depth B. If one uses grating elements 1 whose local Blaze angle and, thus, grating depth as indicated in equation (8) changes with the position on the grating, one obtains a maximum efficiency according to FIG. 10, since the diffraction efficiency in the xe2x88x921 order xcex7(xe2x88x921) is a function of the Blaze depth. As FIG. 10 shows, the diffraction efficiency xcex7(xe2x88x921) also depends on the materials used. In FIG. 10, reference number 100 designates the diffraction efficiency xcex7(xe2x88x921) for a wavelength of xcex=13.5 nm for ruthenium; reference number 102 is for palladium; reference number 104 is for rhodium; and reference number 106 is for gold. As follows from FIG. 10, a highest efficiency of 0.7 is achieved with ruthenium. A coating of palladium or rhodium, which has better long-term properties, only has an efficiency xcex7(xe2x88x921) of 0.67, which is only around 3% poorer. Gold is conventionally used for synchrotron gratings, but as curve 106 reveals, it has a much poorer efficiency than the mentioned materials at xcex=13.5 nm. To simplify fabrication, all individual gratings can be produced with the same Blaze depth of, for example, 25 nm, and even so a diffraction efficiency xcex7(xe2x88x921) of greater than 55% or 0.55 is achieved. FIG. 11 shows an EUV projection exposure system with a grating element 1 according to the invention. The EUV projection exposure system comprises a light source 3, and a collecting optical component or so-called collector 5, which is configured as a nested collector according to the German patent application DE-A-10102934, submitted on Jan. 23, 2001 to the German Patent Office for the Applicant, whose disclosure content is also included in its entirety in the present application. Collector 5 images light source 3, which lies in an object plane 202 of an illumination system, in a secondary light source 4 in or near the diaphragm plane of diaphragm 7.3. In this embodiment the illumination system for illuminating an arc shaped field in the field plane 22 comprises light source 3, grating element 1, diaphragms 7.1, 7.2, 7.4, 7.5, 7.6 and 7.7 as well as diaphragm 7.3, and as further optical elements, facetted mirrors 29.1, 29.2, and mirrors 30.1, 30.2 and 32. In the present case, light source 3, also referred to as a primary light source, which can be, for example, a laser plasma source or a plasma discharge source, is arranged in the object plane 202 of the illumination system; an image of light source 3, which is also termed a secondary light source 4, comes to lie in an image plane of the illumination system. Between grating element 1 and diaphragm 7.3 are arranged additional diaphragms 7.1, 7.2, in order to block out the light of unwanted wavelengths, especially wavelengths greater than 30 nm. According to the invention, the focus of the xe2x88x921 order will come to lie in the diaphragm plane of diaphragm 7.3, i.e., light source 3 is imaged by collector 5 and grating element 1, which functions as a grating spectral filter in the xe2x88x921 diffraction order almost stigmatically in the diaphragm plane of diaphragm 7.3. Imaging in all other diffraction orders is not stigmatic. Furthermore, the illumination system of the projection system comprises an optical system 20 to form and illuminate a field plane 22 with an annular field. The optical system 20 comprises, as a mixing unit for homogeneous illumination of the annular field, two facet mirrors 29.1, 29.2, as well as two imaging mirrors 30.1, 30.2 and a field-forming grazing-incidence mirror 32. Additional diaphragms 7.4, 7.5, 7.6, 7.7 are arranged in optical system 20 to suppress stray light. The first facet mirror 29.1, so-called field facet mirror, generates a plurality of secondary light sources in or near a plane of the second facet mirror 29.2, so-called pupil facet mirror. The optical elements 30.2, 30.1, 32 following this images the pupil facet mirror 29.2 in an exit pupil 34 of the illumination system, which comes to lie in an entrance pupil of a projection objective 26. Angles of inclination of the individual facets of the first and second facet mirrors 29.1, 29.2 are designed so that images of the individual field facets of the first facet mirror 29.1 are superimposed in a field plane 22 of the illumination system and thus a largely homogenized illuminating of a pattern-bearing mask, which comes to lie in field plane 22, is achieved. A segment of the annular field is formed by field-forming grazing-incidence mirror 32 operating under grazing incidence. A double-faceted illumination system is disclosed, for example, in the U.S. Pat. No. 6,198,793, and imaging and field-forming components are disclosed in PCT/EP/00/07258. The disclosure contents of these publications are fully incorporated in the present application. The pattern-bearing mask arranged in the field plane 22, also known as a reticle, is imaged by means of projection objective 26 in an image plane 28 of field plane 22. Projection objective 26 is a 6-mirror projection objective, such as is disclosed in the U.S. Application No. 60/255,214, submitted on Dec. 13, 2000 at the US Patent Office for the Applicant, or DE-A-10037870, whose disclosure content is fully incorporated in the present Application. An object being exposed, for example, a wafer, is arranged in image plane 28. The invention indicates for the first time an illumination system with which it is possible to select unwanted wavelengths directly after the primary light source. 1 Grating element 3 Light source 4 Secondary light source 5 Collector 7.1, 7.2, 7.3 7.4, 7.5, 7.6 7.7 Diaphragms of the illumination system 8 Cooling device 9, 9.1, 9.2 Individual gratings 10.1, 10.2 Inlet and outlet of the cooling device 11 Incident beam 12 Beam diffracted in 0th order 16 Beam diffracted in the xe2x88x921 order 20 Optical system 22 Field plane 26 Projection objective 28 Image plane of the field plane 29.1, 29.2 Facet mirrors 30.1, 30.2 Imaging mirrors 32 Field-forming mirror 34 Exit pupil of the illumination system 100, 102, 104, 106 Diffraction efficiency xcex7(xe2x88x921) for various materials 200 diaphragm plane 202 object plane
	abstract	For irradiating a layer (3) a radiation beam (7) is directed and focused to a spot (11) on the layer (3), relative movement of the layer (3) relative to the optical element (59) is caused so that, successively, different portions of the layer (3) are irradiated and an interspace (53) between a surface of the optical element (59) nearest to the layer (3) is maintained. Furthermore, at least a portion of the interspace (53) through which the radiation irradiates the spot (11) on the layer (3) is maintained filled with a liquid (91). By directing a gas flow (71-73) to a surface zone (74) of the layer (3), liquid (91) is reliably prevented from passing that surface zone (74), without causing damage to the layer (3). The liquid (91) is drawn away from the layer (3) in the vicinity of the surface zone (74).
	claims	1. A laser welding apparatus for spacer grid of nuclear fuel assembly, comprising:a base frame including a chamber installment hole, a guide rail installed along the chamber installment hole, and a damper arranged in an end of the guide rail;a welding chamber unit assembled with the base frame in guidance by the guide rail and equipped with an operable door in front and a glass window at the top to be airtight;a laser welding unit mounted on the base frame for radiating laser through the glass window to weld spacer grid in the welding chamber unit; anda locking member for fixing the welding chamber unit on the base frame,wherein the locking member comprises:a locking block protruding from a bottom of the welding chamber unit;a locking arm arranged so as to be pivoted to the base frame to support the locking block, the locking arm including a first wing and a second wing which respectively extend in different directions from a pivoting center, the first wing including a convex surface; anda locking pin mounted on the base frame for restricting rotation of the locking arm,wherein the damper restricts movement of the welding chamber unit toward the damper along the guide rail, andwherein the welding chamber unit is fixed on the base frame, such that the welding chamber unit is located adjacent to the damper with the movement of the welding chamber toward the damper being restricted and the damper facing a left side of the locking block, the locking arm, which has been rotated in a first direction, comes in contact with a right side of the locking block with the convex surface of the first wing being in direct contact with the locking block, and the locking pin comes in direct contact with the second wing and restricts the locking arm from further rotating in the first direction. 2. The welding apparatus for spacer grid of nuclear fuel assembly according to claim 1, wherein the base frame further comprises a glass cover prepared to cover the glass window. 3. The welding apparatus for spacer grid of nuclear fuel assembly according to claim 2, wherein a ventilation hole interconnected with the welding chamber unit is formed in a flange to which the glass window is fixed, and the flange is characterized by a ventilation valve arranged in the flange and controlled to be opened or closed by the glass cover. 4. The welding apparatus for spacer grid of nuclear fuel assembly according to claim 1, wherein the welding chamber unit comprises a position detecting unit for detecting the standard position of a driving pad which rotates a welding rotation plate in which the spacer grid is settled, and outputting an electrical detection signal. 5. The welding apparatus for spacer grid of nuclear fuel assembly according to claim 1, the locking member further comprises a handle bar protruding from the locking arm in a rotation axis direction of the locking arm.
	summary
	claims	1. A method comprising:characterizing variations in feature dimensions of an integrated circuit that is to be fabricated in accordance with a design, by a set of processes that produce topographical variations in the integrated circuit, the variations in feature dimension being caused by the topographical variations, the set of processes comprising at least a first process, wherein the first process comprising electroplated copper deposition or chemical mechanical polishing, the set of processes further comprising at least a second process, the second process comprising a lithographic or etching process; andwherein the act of characterizing the variations comprises analysis of impacts of interactions between the first process and the second process. 2. The method of claim 1 in which the variations that are characterized are for a damascene process flow. 3. The method of claim 1 in which the variations that are characterized corresponds to line width variations based upon thickness variation on a wafer surface. 4. The method of claim 1 in which the etching process comprises a plasma etching process. 5. The method of claim 1 in which the characterizing is provided as a service in a network. 6. The method of claim 5 in which the network comprises an intranet, an extranet, or an internet, and the characterizing is provided in response to user requests. 7. The method of claim 1 further including using an electronics design automation (EDA) tool in conjunction with the characterizing. 8. A method comprising:using a pattern-dependent model of topographical variation to predict feature dimension variations or electrical characteristics of an integrated circuit that is to be fabricated in accordance with a design by a set of processes that produce topological variation, the set of processes comprising at least a first process, wherein the first process comprising electroplated copper deposition or chemical mechanical polishing, the set of processes further comprising at least a second process, the second process comprising a lithographic or etching process; andwherein the act of predicting feature dimension variations or electrical characteristics comprises analysis of impacts of interactions between the first process and the second process, andverifying that the predicted feature dimensions or electrical characteristics conform to the design. 9. A method comprising:using a pattern-dependent model of topographical variation to predict characteristics of an integrated circuit that is to be fabricated in accordance with a design by a set of processes, the set of processes comprising at least a first process, wherein the first process comprising electroplated copper deposition or chemical mechanical polishing, the set of processes further comprising at least a second process, the second process comprising a lithographic or etching process; andwherein the act of predicting characteristics comprises analysis of impacts of interactions between the first process and the second process, andverifying that the predicted characteristics conform to the design,the characteristics including feature dimensions or electrical characteristics. 10. The method of claim 9 in which the set of processes comprises plasma etch and the characteristics include sidewall angle, trench width, or trench depth. 11. The method of claim 9 in which the characteristics include feature dimensions. 12. The method of claim 9 in which the characteristics include electrical characteristics. 13. The method of claim 9 in which the variations are for a damascene process flow. 14. The method of claim 9 in which the variations corresponds to line width variations based upon thickness variation on a wafer surface. 15. The method of claim 9 in which the characteristics comprise feature width. 16. The method of claim 9 in which the characteristics are associated with all of the integrated circuit. 17. The method of claim 9 in which the characteristics are associated with less than all of the integrated circuit. 18. The method of claim 9 in which the verifying of the predicted characteristics includes verifying feature widths. 19. The method of claim 9 in which the verifying of the predicted characteristics also includes verifying the topographical variation. 20. The method of claim 9 in which the verifying of the predicted characteristics includes verifying physical and electrical parameters that result from feature width variation. 21. The method of claim 9 in which the prediction or verification is done in response to a request received electronically from a network. 22. The method of claim 9 in which the prediction or verification is provided as a web service. 23. The method of claim 9 in which using a pattern-dependent model of topographical variation to predict characteristics of the integrated circuit includes using the model with respect to at least two different process features. 24. The method of claim 23 in which the process features comprise process recipes. 25. The method of claim 24 in which the process recipes include different tool settings for a tool. 26. The method of claim 24 in which the process recipes include power settings. 27. The method of claim 24 in which the process recipes include etch times. 28. The method of claim 24 in which the process recipes include polish times. 29. The method of claim 24 in which the process recipes include deposition times. 30. The method of claim 24 in which the process recipes include pressures. 31. The method of claim 23 in which the process features comprise tools. 32. The method of claim 31 in which the tools comprise tools made by two different vendors. 33. The method of claim 23 in which the process features comprise consumables. 34. The method of claim 33 in which the consumables comprise photoresists or mask types. 35. The method of claim 23 in further including choosing among the process features based on the prediction. 36. A method comprising:using a pattern-dependent model to predict variations in feature dimensions of an integrated circuit that is to be fabricated in accordance with a design by a set of processes that include a fabrication process that will impart topographical variation to the integrated circuits, the set of processes further comprising at least a second process, the second process comprising a lithographic or etching process; andwherein the act of predicting variations comprises analysis of impacts of interactions between the fabrication process and the second process. 37. The method of claim 36 in which the variations are for a damascene process flow. 38. The method of claim 36 in which the variations that are characterized corresponds to line dimension variations based upon thickness variation on a wafer surface. 39. The method of claim 38 in which the line dimension variations comprise line width variations. 40. The method of claim 36 in which the predicting is provided as a service in a network. 41. The method of claim 40 in which the network comprises an intranet, an extranet, or an internet, and the predicting is provided in response to user requests. 42. The method of claim 36 also including using an electronics design automation (EDA) tool in conjunction with the predicting. 43. A method comprising:using a pattern-dependent model to predict characteristics of an integrated circuit that is to be fabricated in accordance with a design by a process that includes (a) a fabrication process that will impart topographical variation to the integrated circuit and (b) a lithography or etch process, wherein the act of predicting characteristics comprises analysis of impacts of interactions between the fabrication process and the lithographic or etch process, andcertifying that the predicted characteristics meet specifications of the design. 44. A method comprising:using a pattern-dependent model to predict characteristics of an integrated circuit that is to be fabricated in accordance with a design by a process that includes (a) a fabrication process that will impart topographical variation to the integrated circuit and (b) a subsequent lithography or etch process wherein the act of predicting characteristics comprises analysis of impacts of interactions between the fabrication process and the lithographic or etch process, andcertifying that the predicted characteristics resulting from the process up to the lithography or etch process will meet specifications of the design. 45. A computer program product comprising a tangible computer usable medium having executable code to execute a process, the process comprising:characterizing variations in feature dimensions of an integrated circuit that is to be fabricated in accordance with a design, by a set of processes that produce topographical variations in the integrated circuit, the variations in feature dimension being caused by the topographical variations, the set of processes comprising at least a first process, wherein the first process comprising electroplated copper deposition or chemical mechanical polishing, the set of processes further comprising at least a second process, the second process comprising a lithographic or etching process; andwherein the act of characterizing the variations comprises analysis of impacts of interactions between the first process and the second process. 46. The computer program product of claim 45 in which the variations that are characterized are for a damascene process flow. 47. The computer program product of claim 45 in which the variations that are characterized corresponds to line width variations based upon thickness variation on a wafer surface. 48. The computer program product of claim 45 in which the etching process comprises a plasma etching process. 49. A system comprising:means for characterizing variations in feature dimensions of an integrated circuit that is to be fabricated in accordance with a design, by a set of processes that produce topographical variations in the integrated circuit, the variations in feature dimension being caused by the topographical variations, the set of processes comprising at least a first process, wherein the first process comprising electroplated copper deposition or chemical mechanical polishing, the set of processes further comprising at least a second process, the second process comprising a lithographic or etching process; andwherein the means for characterizing the variations comprises means for analysis of impacts of interactions between the first process and the second process. 50. The system of claim 49 in which the variations that are characterized are for a damascene process flow. 51. The system of claim 49 in which the variations that are characterized corresponds to line width variations based upon thickness variation on a wafer surface. 52. The system of claim 49 in which the etching process comprises a plasma etching process. 53. A computer program product comprising a tangible computer usable medium having executable code to execute a process, the process comprising:using a pattern-dependent model of topographical variation to predict characteristics of an integrated circuit that is to be fabricated in accordance with a design by a set of processes, the set of processes comprising at least a first process, wherein the first process comprising electroplated copper deposition or chemical mechanical polishing, the set of processes further comprising at least a second process, the second process comprising a lithographic or etching process, wherein the act of predicting characteristics comprises analysis of impacts of interactions between the first process and the second process,verifying that the predicted characteristics conform to the design, andthe characteristics including feature dimensions or electrical characteristics. 54. The computer program product of claim 53 in which the set of processes comprises plasma etch and the characteristics include sidewall angle, trench width, or trench depth. 55. The computer program product of claim 53 in which the characteristics include feature dimensions. 56. The computer program product of claim 53 in which the characteristics include electrical characteristics. 57. The computer program product of claim 53 in which the characteristics comprise feature width. 58. The computer program product of claim 53 in which the verifying of the predicted characteristics includes verifying feature widths. 59. The computer program product of claim 53 in which the verifying of the predicted characteristics also includes verifying the topographical variation. 60. The computer program product of claim 53 in which the verifying of the predicted characteristics includes verifying physical and electrical parameters that result from feature width variation. 61. A system comprising:means for using a pattern-dependent model of topographical variation to predict characteristics of an integrated circuit that is to be fabricated in accordance with a design by a set of processes, the set of processes comprising at least a first process, wherein the first process comprising electroplated copper deposition or chemical mechanical polishing, the set of processes further comprising at least a second process, the second process comprising a lithographic or etching process, wherein the act of predicting characteristics comprises analysis of impacts of interactions between the first process and the second process,means for verifying that the predicted characteristics conform to the design, andthe characteristics including feature dimensions or electrical characteristics. 62. The system of claim 61 in which the set of processes comprises plasma etch and the characteristics include sidewall angle, trench width, or trench depth. 63. The system of claim 61 in which the characteristics include feature dimensions. 64. The system of claim 61 in which the characteristics include electrical characteristics. 65. The system of claim 61 in which the characteristics comprise feature width. 66. The system of claim 61 in which the means for verifying of the predicted characteristics includes means for verifying feature widths. 67. The system of claim 61 in which the means for verifying of the predicted characteristics also includes means for verifying the topographical variation. 68. The system of claim 61 in which the means for verifying of the predicted characteristics includes means for verifying physical and electrical parameters that result from feature width variation.
	description	The invention relates to the use of a sample carrier in a charged particle instrument, a method of using such a sample carrier, and an apparatus equipped to use such a sample carrier. Sample carriers are used to carry samples in a charged particle instrument such as in a Scanning Electron Microscope (SEM) and Focused Ion Beam instruments (FIB). Charged particle instruments such as a SEM's and a FIB's are known per se. Charged particle instruments such as a SEM or a FIB employ a focused beam of charged particles, such as electrons or ions, to irradiate a sample with a current of typically between 1 pA and 100 nA. The focused beam (a beam of charged particles with an energy of e.g. between 0.1 keV and 30 keV) is scanned over the sample. In response to the impinging charged particles secondary radiation emanates from the sample in the form of e.g. secondary electrons, X-rays, light, etc. As the beam impinges at one point at a time only, this secondary radiation is (at each moment) position dependant. By detecting the secondary radiation of interest, the sample may be analysed and/or an image may be formed. To analyse a sample in a charged particle instrument the sample is normally mounted on a stub. The stub may in turn be mounted on e.g. a stage being part of the charged particle instrument. This stage positions the sample such that an area of interest of the sample is scanned by the charged particle beam. As the sample is irradiated with charged particles, charging of the sample may occur. Charging of the sample influences the position where the beam of charged particles impinges on the sample. Charging also influences e.g. the amount of secondary electrons emanating from the sample. Therefore charging of the sample is a known problem when using a charged particle instrument. The simplest way to avoid charging is by forming the stub from a metal, and in the charged particle instrument connecting the stub (with the sample mounted on it) to a fixed voltage, such as ground potential. Before the sample is inspected in the charged particle instrument it is often observed in an optical microscope. To that end the sample is mounted on a microscope slide. As known to the person skilled in the art conventional microscope slides are made of glass and are highly insulating. Therefore conventional microscope slides are not suited to be used as a sample carrier in a charged particle instrument. A disadvantage of the stubs used in charged particle instrument is that they are not compatible with those types of optical microscopy using transmission of light through the sample. Therefore the sample carriers used in a charged particle instrument are not suited as sample carrier in an optical microscope. The invention aims to provide a sample carrier that can be used in both an optical microscope using transmission of light through the sample and that can be used in charged particle instrument. The invention also aims to provide an alternative to the known sample carriers for charged particle instruments. To that end the invention comprises the use of an optical microscope slide coated with a transparent conductive layer of a metal oxide as sample carrier in a scanning charged particle apparatus. The invention is based on the insight that a microscope slide with a conductive coating of metal oxide is very well suited to be used as sample carrier for a charged particle instrument. Such a microscope slide is known from e.g. SPI Supplies Division, Structure Probe, Inc; West Chester, Pa. 19381-0656 USA, and is sold under the name “SPI Supplies® Brand Indium-Tin-Oxide (ITO) Coated Microscope Slide”. These microscope slides are intended to be used in cases where a sample, such as living tissue, is observed at e.g. body temperature. The coating is used as a resistive heater. The known microscope slide comprises a glass, quartz or polymer carrier, at one side coated with a electrically conductive layer of indium-tin oxide. The conductive layer has a sheet resistance of between 8 Ω and 100 Ω. The conductive layer is not covered with an insulating layer. The microscope slide is transparent to light and can be used as a normal microscope slides. By passing a current through the conductive layer the slides are heated. It is remarked that similar microscope slides are known from other supplier. However, sheet resistance, exact composition of the conductive layer and method of attaching the conductive layer to the carrier may differ. As the current of the charged particle beam is less than 100 nA or even less than 1 nA, a sheet resistance of less than 1 kΩ or even less than 1 MΩ results in sufficient low resistance so as to cause negligible charging. By using the microscope slide in a charged particle instrument and connecting the conductive layer to a fixed potential—such as ground potential-charging of the glass or polymer of the microscope slide is avoided. As the conductive layer itself is not covered with an insulating layer, a sample mounted on the layer is connected to the conductive layer and thereby charging of the sample is avoided. Such layers can be made very smooth, making them well suited for inspection not only in an optical microscope but also in a charged particle instrument. A measurement of the surface roughness of an ITO (Indium Tin Oxide) layer with a thickness of 365 nm, corresponding with a sheet resistance of 10 Ω, is given in ‘Super smooth metal oxide thin films using closed field reactive magnetron spuftering’, J. M. Walls et al., 48th Annual Technical Conference Proceedings of the Society of Vacuum Coaters (2005), 36-40. These measurements show that the roughness of the layer shows a peak-to-peak roughness of 4.4 nm and an RMS roughness of 0.453 nm, comparable to the roughness of the underlying glass surface. It is remarked that in US patent application number US2006/0284108A1 a microscope slide is described as sample carrier in a charged particle apparatus. FIG. 2 of the mentioned patent application shows a particle optical apparatus where a microscope slide is used as sample carrier, on which microscope slide a vacuum seal is formed. The problem of charging is mentioned in the corresponding part of the description, and a solution is proposed by the use of an ESEM column, that is: to work in a vacuum with a partial pressure of about 0.1 mbar to 10 mbar of e.g. water, resulting in a reduction of charging. As another possibility mentioned is to evaporate a metal onto a microscope slide. As known to the person skilled in the art this will normally result in a microscope slide with a much reduced transparency and a surface roughness inferior to the surface roughness reported in the before mentioned article of Walls et al. The patent application does not mention the use of a metal oxide as a coating for microscope slides. It is also remarked that U.S. Pat. No. 4,183,614 describes a microscope slide with a slightly conductive coating. It describes in its column 3, lines 47 to 50 that such a coating is beneficial for dissipating charge. As known to users of optical microscopes small insulating particles, such as dust particles, may get charged while bringing them onto a microscope slide. As a result the particles may group together or form clusters, which may give rise to artifacts. The microscope slides with a conductive coating may be used to eliminate this effect. However, dissipating initial charge from e.g. a charged dust particle differs from the removal of an impinging current in a vacuum. U.S. Pat. No. 4,183,614 does not mention or imply the use of such a microscope slide in a particle-optical apparatus, such as a SEM. In a further embodiment the metal oxide is ITO (Indium Tin Oxide). ITO is a well known transparent coating for e.g. glasses and is used in the microscope slides sold by SPI. Other uses are in e.g. the conductive patterns on glass in LCD displays, plasma displays, etc. In another embodiment of the use of an optical microscope slide coated with a transparent conductive layer as sample carrier in a charged particle apparatus the charged particle instrument is a SEM or a FIB. In an aspect the invention provides a method for observing a sample, the method comprising providing an optical microscope slide, at least one side of said microscope slide covered with a transparent conductive layer, providing a sample, and mounting the sample on the optical microscope slide at the side of the slide covered with the transparent conductive layer, characterized in that the method further comprises inspecting or modifying the sample in an evacuated volume of a charged particle apparatus while the sample is mounted on the microscope slide, said conductive layer electrically connected to a fixed potential. In an embodiment of the method according to the invention the fixed potential is earth potential. By grounding the microscope slide the impinging current is returned to earth. In another embodiment to the method according to the invention the method further comprises observing the sample with an optical microscope. In a further embodiment of the method according to the invention the metal oxide comprises indium-tin oxide (ITO). In another embodiment of the method according to the invention the charged particle apparatus is a SEM or a FIB. In another aspect the invention provides an apparatus for inspecting a sample, said apparatus equipped with an optical microscope to observe the sample, and a charged particle column to observe or modify the sample with a beam of charged particles, is according to the invention characterized in that the optical microscope is equipped to inspect the sample while it is mounted on a microscope slide, said microscope slide coated with a conductive layer, the charged particle column is equipped to inspect or modify the sample while it is mounted on the microscope slide, and the conductive layer of the microscope slide is kept at a constant voltage while observing or modifying the sample with the beam of charged particles. It is remarked that an apparatus equipped with an optical microscope and a charged particle column is known and was commercially sold by Akashi Seisakusho Ltd, Japan, under the name LEM-2000. The apparatus is equipped with an optical microscope with a magnification of between 50× and 250×, and a TEM column for observing the sample with a magnification of between 250× and 45000×. This apparatus is equipped to observe samples mounted on grids with a diameter of 7 mm. It is impossible to observe samples mounted on a microscope slide with this apparatus. It is also remarked that an apparatus equipped with an optical microscope and a charged particle column is sold by Topcon, Japan as the Opti-SEM 300. This apparatus is equipped with an optical microscope and a SEM column. However, the optical microscope is not capable to observe light transmitted through the sample. The apparatus is not equipped to handle microscope slides, nor is it equipped to keep the conductive layer of such a slide at constant potential. In an embodiment of the apparatus according to the invention the apparatus is equipped to inspect the sample by using light transmitted through the sample. In another embodiment of the apparatus according to the invention the apparatus is equipped to irradiate the sample with the beam of charged particles while it is simultaneously inspected with the optical microscope. In yet another embodiment of the apparatus according to the invention the charged particle column is a FIB column or a SEM column. In still another apparatus according to the invention the region of interest that is observed with the optical microscope is centred with the region of interest that is observed with the charged particle column. In this embodiment it is possible to observe a region of interest simultaneously with the charged particle column and the optical microscope. It is remarked that it is possible that both the optical microscope and the charged particle column observe the sample from the same side, but that it is also possible that they observe the sample from opposite sides, i.e. that the optical microscope views the sample through the microscope slide. In yet another embodiment of the apparatus according to the invention the apparatus is equipped to form a vacuum seal against the microscope slide when the sample is observed with a beam of charged particles. As known to the person skilled in the art a sample to be inspected and/or analysed in a charged particle instrument must be placed in an evacuated environment. The microscope slide shows a perfectly flat surface, on which a vacuum seal can be formed with e.g. an O-ring. This makes the microscope slide especially suited for use in a SEM of the type described in the before mentioned US patent application number US2006/0284108A1. FIG. 1 schematically shows a microscope slide according to the invention. The microscope slide 10 comprises a glass plate 1 covered with a thin, conductive layer 2 of a metal oxide, A sample 4 is placed on the side of the microscope slide on which the conductive layer 2 is deposited. Herewith the sample 4 is in electrical contact with the conductive layer 2. By connecting the conductive layer 2 to a fixed potential, such as ground potential, charging of the sample is avoided. This can be done by contacting the conductive layer with a metal holder, of which a part 3 is shown. FIG. 2 schematically shows a particle-optical apparatus equipped to use the microscope slide according to the invention. A vacuum chamber 100 is evacuated by vacuum pumps (not shown). On the vacuum chamber a charged particle column 102 is mounted. The charged particle column comprises a charged particle source 104 producing a beam of charged particles, such as electrons or ions, along a particle-optical axis 106. The charged particles are manipulated by lenses 108 and deflector 110, thereby enabling focusing of the charged particle beam onto the sample 4 and scanning it over the sample. Where the charged particle beam irradiates the sample secondary radiation in the form of e.g. secondary electrons, backscattered electrons or X-rays are generated. This secondary radiation is detected by a detector 112. The sample 4 is mounted on a microscope slide 10 according to the invention. The microscope slide is pushed against a metal holder 3 by resilient member 5, thereby ensuring an electric contact between the metal holder 3 and the microscope slide 10. A flexible wire 7 connects the metal holder 3 with a fixed potential, that is: it is grounded via the vacuum chamber. The metal holder 3 and the microscope slide 10 are mounted on a stage 114, so that an area of interest on the sample 4 can be brought on the particle-optical axis 106. An optical microscope 130 is mounted on the vacuum chamber 100 in such a way that the optical axis of the optical microscope and the particle-optical axis 106 of the charged particle column 102 coincide. Therefore the region of interest observed by the optical microscope 130 is aligned with the region of interest observed by the charged particle column 102. Light from a light source 136, such as a laser, a LED light or an incandescent light bulb, is passed through the wall of the vacuum chamber 100 through window 134 and focused on the sample 4 by mirror 132. Mirror 132 shows a hole 116 to pass the beam of charged particles produced by the charged particle column 102 to the sample. The person skilled in the art will recognize that many variations are possible. The light source 136 can e.g. be mounted inside the vacuum chamber 100, so that window 134 is not necessary anymore. A mirror focusing the light onto the sample need not be used. Also the microscope 130 can be positioned inside the vacuum chamber 100. The path of light can be reversed, that is: the light may irradiate the sample through the microscope slide 10 and the optical microscope 130 can view the sample from the same side as where the particle beam irradiates the sample.
	claims	1. A corona treatment apparatus for surface treating a web of material comprising:a frame;a rotatable ground roller mounted to the frame;a mount attached to the frame;a high-voltage electrode mounted to the mount and mounted proximate to the ground roller;anda motor directly connected to the mount and configured to adjust the position of the mount and the electrode relative to the frame. 2. The corona treatment apparatus of claim 1, further comprising a sensor configured to sense a thickness of the web of material, and a processor in communication with the sensor and in communication with the motor, the processor configured to activate the motor to adjust the position of the mount and the electrode relative to the frame when a thickened area of the web of material is sensed by the sensor. 3. The corona treatment apparatus of claim 1, further comprising a second motor attached to the mount and configured to adjust the position of the mount and the electrode relative to the frame. 4. The corona treatment apparatus of claim 3, further comprising a sensor configured to sense a thickness of the web of material, and a processor in communication with the sensor and in communication with the motors, the processor configured to activate the motors to adjust the position of the mount and the electrode relative to the frame when a thickened area of the web of material is sensed by the sensor. 5. The corona treatment apparatus of claim 1, wherein the ground roller has an axis around which the ground roller rotates, the mount includes a pair of first mounting plates movably connected to the frame, the first mounting plates being connected to the frame by a pair of pins engaged within elongated angled slots, the slots being angled relative to the axis of the ground roller such that the first mounting plates are moveable relative to the frame in a direction which is angled relative to the axis of the ground roller when the motor is activated, a second mounting plate attached to the first mounting plates, the second mounting plate being moveable relative to the first mounting plates in a direction which is parallel to the axis of the ground roller, the electrode being attached to the second mounting plate. 6. The corona treatment apparatus of claim 5, further including a plurality of wheels mounted between the second mounting plate and the first mounting plates, the wheels being attached to the second mounting plate. 7. The corona treatment apparatus of claim 5, further including a motor engaging block attached to the second mounting plate and through which a drive shaft of the motor extends, the motor engaging block being moveable relative to the first mounting plates. 8. The corona treatment apparatus of claim 7, wherein the motor engaging block is attached to the second mounting plate by a plurality of pins engaged through a slot. 9. The corona treatment apparatus of claim 5, further comprising a second motor attached to the mount and configured to adjust the position of the mount and the electrode relative to the frame. 10. The corona treatment apparatus of claim 9, further comprising a sensor configured to sense a thickness of the web of material, and a processor in communication with the sensor and in communication with the motors, the processor configured to activate the motors to adjust the position of the mount and the electrode relative to the frame when a thickened area of the web of material is sensed by the sensor. 11. The corona treatment apparatus of claim 1, wherein the ground roller has an axis around which the ground roller rotates, the frame has an elongated slot provided therethrough, and the mount includes a support having an end portion extending through the elongated slot in the frame, mounting plates attached to the support and to the electrode, wherein the support, the mounting plates and the electrode can be moved vertically relative to the ground roller when the motor is activated. 12. The corona treatment apparatus of claim 11, wherein the mounting plates comprises a pair of first mounting plates attached to the support, a pair of second mounting plates attached to the first mounting plates, the second mounting plates being moveable relative to the first mounting plates in a direction which is parallel to the axis of the ground roller, the electrode being attached to the second mounting plates. 13. The corona treatment apparatus of claim 12, further including a plurality of wheels mounted between the second mounting plates and the first mounting plates, the wheels being attached to the second mounting plates. 14. The corona treatment apparatus of claim 11, wherein the support is rotatable relative to the frame. 15. The corona treatment apparatus of claim 11, further comprising a second motor attached to the mount and configured to adjust the position of the mount and the electrode relative to the frame. 16. The corona treatment apparatus of claim 15, further comprising a sensor configured to sense a thickness of the web of material, and a processor in communication with the sensor and in communication with the motors, the processor configured to activate the motors to adjust the position of the mount and the electrode relative to the frame when a thickened area of the web of material is sensed by the sensor. 17. A method comprising:passing a web of material between a ground roller and an electrode, the web of material having a first thickness and a second thickness, the first thickness being greater than the second thickness;sensing the thickness of the web of material prior to entry of the web of material between the ground roller and the electrode;upon sensing the first thickness of the web of material, activating a motor to move the electrode a first predetermined distance away from the ground roller; andupon sensing the second thickness of the web of material, activating the motor to move the electrode a second predetermined distance away from the ground roller, the second predetermined distance being less than the first predetermined distance. 18. The method of claim 17, wherein two motors are used to move the electrode.
	description	The present invention relates generally to the field of nuclear power generation and in particular to a new and useful tube support bar for retaining and positioning water tubes within a nuclear steam generator. Water tubes for nuclear steam generators are typically 0.5 to 0.75 inches in diameter with a nominal wall thickness of 0.045 inches. In the once-through steam generator design, the tube bundle consists of straight tubes. In a recirculating steam generator, depicted in FIG. 1, the tube bundle is made up of U-tubes. In a pressurized water nuclear power station, steam generators, which are large heat exchangers, transfer heat, produced via nuclear reactions in the reactor core, from a primary water coolant to a secondary water coolant that drives the steam turbine. The primary coolant is pressurized, which allows the primary water coolant to be heated in the reactor core with little or no boiling. For example, in a light water reactor, the primary coolant is pressurized to about 2250 psia and heated to about 600 deg F. in the reactor core. From the reactor, the primary water coolant flows to a steam generator, where it transfers heat to the secondary coolant. In a U-tube, or recirculating steam generator, the primary coolant enters at the bottom of the steam generator, flows through tubes having an inverted U-shape transferring heat to the secondary coolant, and then exits at the bottom of the steam generator. The secondary coolant is pressurized only to a pressure below that of the primary side, and boils as it flows along the outside of the tubes, thereby producing the steam needed to drive the turbine. Nuclear steam generators must be capable of handling large quantities of two-phase secondary coolant moving at high flow rates, and are therefore very large structures. For example, a nuclear U-tube steam generator can weigh more than 450 tons, with a diameter exceeding 12 feet and an overall length of greater than 70 feet. It may contain as many as 9,000 or more of the long, small diameter, thin-walled U-shaped tubes. For a general description of the characteristics of nuclear steam generators, the reader is referred to Chapters 47 and 52 of Steam/Its Generation and Use, 40th Edition, The Babcock & Wilcox Company, Barberton, Ohio, U.S.A., ©1992, the text of which is hereby incorporated by reference as though fully set forth herein. Heat exchangers such as nuclear steam generators require tube restraints or supports, to position the tubes and to restrain the tubes against flow induced vibration forces. Tube support bars are therefore used in some nuclear steam generators is to keep the small diameter, thin wall heat transfer tubes in position and to prevent damage to the tubes due to vibration or external loads. In one tube support structure flat tube support bars are positioned at intervals along the tube bundle within the cylindrical shroud of the steam generator, forming lattice or tube support bar arrays. Each tube support bar array consists of two spaced rings that hold a latticework of crisscrossing flat bars between them. The flat bars, intersecting each other on their edges, form a diamond shape around each tube, thereby providing good vibration dampening yet allowing the steam-water mixture to flow through the tube bundle with minimal pressure drop. One known type of lattice tube support bar array is manufactured by Babcock & Wilcox Canada Ltd. The lattice tube support bar array has a plurality of flat bars aligned parallel to one of two directions, for supporting the multiplicity of water tubes in the steam generator. When bars of different direction cross over each other, they form angles at bar intersections of 60° and 120°. Some of the bars, termed high-bars, provide most of the strength and rigidity of the array. Other smaller bars, termed low-bars, form a finer latticework that separates each tube. Low-bars comprise the majority of the bars in the array, and are about 1 inch high. Each low-bar is a unitary structure having flat sides made of a single material, typically stainless steel. High-bars, about 3 inches in height, are used about every 4 to 8 bars in the array, and have slots in their edges to permit bars arranged in the other direction to cross at the same level within a surrounding peripheral ring. The slots are typically 1 inch deep for low-bar intersections and 1½ inches deep for high-bar intersections. The high-bars are used to help position the low-bars within the array, and to transmit accumulated load to a peripheral heavy structural ring surrounding the bars. The peripheral heavy ring is connected to the outer shroud and shell of the steam generator, thereby conveying the support load to the shroud and shell. As shown with exaggeration in FIG. 2, there is generally a gap between the heat exchanger tubes 90 and the low-bars 30, which is produced by the tolerance of the bar manufacture and is required for assembly. Similarly, gaps may exist between the heat exchanger tubes and the high-bars. Flow of steam and water past the tube induces vibrations which may not be effectively restrained due to the inherent gap. This in turn may reduce the tube life expectancy. One known anti-vibration support is disclosed in U.S. Pat. No. 5,072,786, which describes a tube support bar design using a plurality of special hairpin springs. For a typical nuclear steam generator, this design requires the manufacture and assembly of a very, very large number of spring parts, so that it is difficult to apply the idea in practice. Therefore a new design for an anti-vibration tube support which reduces vibration, yet is easy to manufacture and install would be welcomed by industry. The present invention is drawn to a new apparatus and method for eliminating the gap between tubes and their respective support tube support bars in a nuclear steam generator, whereby the tubes are disposed in the correct positions, and whereby fretting and vibration damage are substantially eliminated. The tube support bars are made of special bimetallic bars or strips. The tube support bar is made by taking a first flat elongated metallic bar and attaching it to a second flat metallic bar at specific intervals. The second flat metallic bar has a coefficient of thermal expansion greater than that of the first bar. The tube support bars are flat during manufacture and installation at a first temperature, such as room temperature. At a second, or operating temperature, higher than the first temperature, however, each support bar automatically forms a plurality of “hill-shape” springs. Such “hill-shaped” springs engage the adjacent tube, thereby eliminating the gap between the tube and its respective support. The springs are not formed at room temperature, thereby providing a suitable clearance to assure ease of installation of tubes, or, alternatively, making the support bar easy to install after the tubes are in place. It is therefore an object of the present invention to provide a tube support bar which minimizes gaps between the tubes and the support bar. A further object of the invention is to minimize flow induced vibration of the tubes in a steam generator, thereby extending the useful life of the tubes. It is a still further object of the invention to provide a tube support bar which is easy to manufacture, install, or remove for replacement. Accordingly, an improved tube support structure is provided for use within an array of generally parallel heat exchanger tubes. The tube support structure has a tube support bar for use in operation between a pair of tubes. The bar is made of a first metallic strip attached to a second metallic strip at spaced intervals. The first strip has a coefficient of thermal expansion greater than the second strip. At a first temperature, the first and second strips are flat. At a second temperature higher than the first temperature, the first strip takes on a convex shape. In another embodiment, a support for heat transfer tubes in a steam generator is provided. The support includes a plurality of bars installed between the heat transfer tubes so that a gap exists between the bars and the heat transfer tubes. Spring means are welded to at least one of the bars at intervals, with the spring means having a thinner thickness than the bar. The spring means and the bar have different thermal expansion coefficients so that at a non-operating temperature of the steam generator the spring means does not contact the adjacent tube and at the operating temperature of the steam generator the spring means contacts the adjacent heat tube. In yet another embodiment, a method is provided for making a tube support bar for supporting heat transfer tubes in a steam generator. A first metal layer is welded to a second metal layer at intervals to form a support bar. The first metal layer and the second metal layer have different thermal expansion coefficients so that at a non-operating temperature of the steam generator the bar is flat, and at the operating temperature of the steam generator the first layer forms a convex shape between the intervals. Several support bars are installed in the steam generator so that a gap exists between the tubes and the support bars. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming part of this disclosure. For a better understanding of the present invention, and the operating advantages attained by its use, reference is made to the accompanying drawings and descriptive matter, forming a part of this disclosure, in which a preferred embodiment of the invention is illustrated. Referring now to the drawings, in which like reference numerals are used to refer to the same or functionally similar elements, FIG. 1 shows a nuclear steam generator 10 having a series of tube support bar arrays 12 at various points along its height for supporting a plurality of water tubes within the steam generator. The tube support bar arrays 12 have a peripheral ring 14 supporting a series of high- and low-bars 3, 130, respectively, as shown in FIG. 3. The high- and low-bars 3, 130 are arranged parallel to one of two directions, with intersection angles of 60° and 120° where bars 3, 130 oriented in different directions cross each other. Referring to FIGS. 4–8, according to the subject invention, low-bar 130 is made of a relatively thin, preferably continuous, first strip or bar 132 secured to a relatively thick, preferably continuous, second strip or bar 134 via attachment 140. Attachment 140 is preferably made at uniformly spaced intervals 136 along and transverse to the length of low-bar 130. First strip 132 is selected to have a coefficient of thermal expansion which is higher than that of the second strip. As shown in FIGS. 6 and 7, at a given temperature, typically room temperature or standard temperature, both strips 132 and 134 are flat, making it easy to insert heat exchanger tubes 90 within bars 130, or, alternatively, to insert bars 130 between rows of tubes 90. At higher temperatures the greater thermal expansion of the first strip causes it to take on a convex shape, as shown in FIG. 8. The following example is provided for the purpose of further illustrating the invention, but is in no way to be taken as limiting. For an application in a nuclear steam generator, low-bar 130 preferably has height of 1″. Low-bar 130 is comprised of a relatively thick strip 134 that is 0.08″ thick and made of SA 240 type 410S, a known bar material, and a relatively thin strip 132 that is 0.02″ thick and made of SB-166 1690, a nickel alloy. Thin strip 132 is spot-welded on the thick strip 134 at intervals 136 of about 1″, or about 2 tube diameters plus tolerance. When the nuclear steam generator is heated to its operating temperature (e.g. about 550 deg. F.), the different thermal expansion coefficients of these two metals (6.51E-06 per deg. F. and 8.13 E-06 per deg. F., respectively) produce a cyclic convex hill shape along the bar 130. Non-linear buckling finite element analysis predicts that the thermal compression stress within the thin strip 132 produces a deformed, convex hill shape as shown in FIG. 9. It is worth noting that only the thin strip 132 is buckled, while thick strip 134 remains straight. Each convex hill shape forms a spring, thereby eliminating the gap between heat exchanger tube 90 and bar 130. This eliminates or reduces flow-induced vibration and fretting, thus increasing tube life expectancy. The improved tube support bars 130 are simple to manufacture and can be made in a regular shop environment. As an added advantage, improved tube support bars 130 can be used without affecting existing steam generator assembly techniques. While specific embodiments and/or details of the invention have been shown and described above to illustrate the application of the principles of the invention, it is understood that this invention may be embodied as more fully described in the claims, or as otherwise known by those skilled in the art (including any and all equivalents), without departing from such principles. As one example, a thin strip 132 could be welded on both sides of thick strip 134 thereby forming a convex hill shape on each side of thick strip 134 when heated to its operating temperature. As another example, the invention could also be applied to the high-bars 3 of a lattice support bar array. The invention could also be applied in retrofit applications, e.g. as an auxiliary anti-vibration bar, and may also be suitable for use in the U-bend region of a recirculating steam generator.
	abstract	To conduct a fluid, the transducer has a flow tube which in operation is vibrated by an excitation assembly and whose inlet-side and outlet-side vibrations are sensed by means of a sensor arrangement. To produce shear forces in the fluid, the flow tube is at least intermittently excited into torsional vibrations about a longitudinal flow-tube axis. The transducer further comprises a torsional vibration absorber which is fixed to the flow tube and which in operation covibrates with the torsionally vibrating flow tube, thus producing reactive torques which at least partially balance torques developed in the vibrating flow tube. One of the advantages of the transducer disclosed is that it is dynamically balanced to a large extent even in the face of variations in fluid density or viscosity.
	abstract	A multi-gun FIB system for nanofabrication provides increased throughput at reduced cost while maintaining resolution. Multiple guns are maintained in modular gun chambers that can be vacuum isolated from the primary vacuum chamber containing the targets. A system can include multiple gun chambers, each of which van include multiple guns, with each gun chamber being capable of being vacuum isolated, so that each gun chamber can be removed and replaced without disturbing the vacuum in other gun chambers or in the main chamber. An optical column is associated with each gun. Optical elements for multiple columns can be formed in a bar that extends into several columns. Some of the optical elements are positioned in the gun chambers and others are positioned in the primary vacuum chamber. A through-the-lens secondary particle collection can be used in connection with each of the individual columns.
048225525	summary	BACKGROUND OF THE INVENTION This invention relates to passively scanning the gamma radiation emission count of a nuclear fuel contained within a fuel rod to determine enrichment levels and uniformity throughout the fuel rod. Nuclear energy has become an important source and supply of energy for many countries throughout the world. The nuclear fuel elements used in the generation of energy usually are composed of a multiplicity of nuclear fuel rods encased within a central reactor core. The nuclear fuels used are typically composed of small pellets of uranium or some other fissionable isotope such as plutonium encased within a long tubular housing commonly known as the fuel rod. Even though a number of pellets are contained within each fuel rod, each pellet must have a proper percentage of fissionable isotope (enrichment) as compared with other pellets. Natural uranium has an enrichment factor of approximately 0.71% which corresponds to the percentage of the highly fissionable uranium-235 (U.sup.235) isotope. After processing to enrich the U.sup.235 isotope content, the uranium content typically has a U.sup.235 enrichment factor ranging from three to five percent and is commonly a uranium dioxide (UO.sub.2) powder derived from gaseous uranium hexaflouride (UF.sub.6). The powder is pelletized for placement within the fuel rods and the fuel rods scanned to assure that all pellets are of a uniform enrichment. The scanning operation is important since a non-homogenous fuel rod having varying enrichments throughout or a deviant average enrichment varying from an established norm could create severe variations in fuel burn-up or heating while a reactor is in operation. Two methods have been previously employed to scan a nuclear fuel contained within a fuel rod for variations in enrichment along the rod (i.e., enrichment uniformity); either a passive or an active system has been used. A passive system detects the natural radiation of the nuclear fuel while an active system induces an additional radiation in the nuclear fuel above that amount irradiated naturally and detects that additional radioactivity. Of these two systems, the most efficient and commonly used method previously employed has been the active system. In an active system, a primary radiation consisting of neutrons from a source such as Californium-252 bombards the nuclear fuel within a fuel rod inducing a secondary radiation of gamma emissions and prompt or delayed fast neutrons. This secondary radiation is then counted to determine fuel content and enrichment. Even though these active systems have proven feasible in the past for scanning ordinary fuel rods containing nuclear fuels, difficulties often arise when scanning recently manufactured nuclear fuels. Manufacturers have begun to add thermal neutron absorbing materials (burnable poisons) to the nuclear fuels encased within a fuel rod which makes scanning such a rod by the common active system impracticable since an ambiguity exists between the primary radiation absorption of the burnable poison and the effects of the fuel enrichment. These burnable poisons such as Gadolinium, Europium and Boron are added to the nuclear fuel to reduce reactivity variations during the fuel burn-up in nuclear reactors. The loss of reactivity through the depletion of the nuclear fuel is partially compensated through the destruction of the burnable poison by neutron absorption during reactor operation. Since the more commonly used active system is limited in its accuracy by the burnable poison content within a nuclear fuel, a passive system is the other alternative which can be used for scanning a nuclear fuel having with it associated burnable poisons. A passive system detects the radiation caused by the natural decay of the nuclear fuel. For example, the 185 KeV (thousand electron volts) gamma radiation emitted by U.sup.235 may be detected in order to determine the enrichment factor of a nuclear fuel using U.sup.235 as the fissionable isotope. The amount of burnable poison associated with the nuclear fuel has no bearing upon the natural gamma radiation emitted by the fuel. Unfortunately, prior attempts to use passive systems for determining enrichment values have been limited since a gamma radiation detector or scintillator of the type commonly used is not able to reliably detect the very low natural irradiations which are associated with conventional fuel rods, and thus the error rate was relatively high. Not only were the prior passive systems limited by this relatively high error rate, but other limitations hindered the passive system such as interference from other gamma radiation energies. Many detectors have an unacceptable poor resolution making the differentiation between the various spectral energy lines difficult. For example, in a nuclear fuel with a high U.sup.238 content, the higher energy gamma radiation from the U.sup.238 daughter, Protactinium-234 is great enough to interfere with the resolution of a detector. Therefore, it is an object of the present invention to provide a method of and an apparatus for passively scanning the gamma radiation emission count of a nuclear fuel contained within a fuel rod to determine enrichment uniformity, and which overcomes the abovenoted limitations of the prior passive systems. It is a further object of the present invention to provide a method of and apparatus for passively scanning the gamma radiation emission count of a nuclear fuel contained within a fuel rod to determine enrichment uniformity, and which are fully automatic. SUMMARY OF THE INVENTION In accordance with the present invention, there are provided a method of and apparatus for passively scanning the gamma radiation emission count of nuclear fuel contained within a fuel rod to determine enrichment uniformity. More particularly, a fuel rod is advanced along a linear path of travel, and the natural gamma radiation emission count at each of a plurality of regularly spaced apart discrete segments along the length of the rod is repeatedly detected at a predetermined energy level as the fuel rod advances along its linear path of travel. The outputs for each of the detecting steps from each segment are summed to obtain a total gamma radiation count for each segment and from the total count obtained from each segment, the enrichment value for each segment and the average enrichment value for the fuel rod may be calculated. In accordance with the present invention, the possibility of error is minimized, since the error potential decreases for each detector added, and the error potential of the system is inversely proportional to the total number of counts obtained. Each fuel rod is also preferably monitored to detect deviations from a specific enrichment value and/or for deviations in the enrichment values of adjacent segments of said fuel rod greater than a predetermined percentage. During operation, fuel rods are stored on a feed table. From the feed table, the fuel rods are sequentially transferred onto a rod advancing means and advanced while its gamma radiation emissions are counted. After scanning, the fuel rods are transferred onto an unloading table from the rod advancing means.
	description	Electric generating plants are usually housed in conventional industrial type buildings above ground. These buildings enclose electric generators, steam turbines and a steam-producing unit. The steam-producing unit may be an oil-fired furnace, a coal burning furnace or a nuclear reactor. While the steam producing unit is usually housed together with generators and turbines, that unit functions independently. This invention provides a support and release structure to mount a nuclear reactor underground in a prebored disposal shaft. This provides the unit with a lifetime stable working platform. At the same time it is always in a constant stand by mode, ready to be dropped and buried in case of an accidental radioactive rupture. It is also in a position to be safely disposed of when it is obsolete and must be discarded. FIG. 1 is a diagram of such an installation. Most of the installation is below ground level 10 from which the bored shaft 14 is excavated. The nuclear reactor 18 and its heat exchanger 26 are enclosed in an envelope 22 suspended in the bored shaft 14. This envelope 22 is preferably bullet shaped and designed to be dropped down that shaft. The envelope and its payload are suspended from a preferably single steel support stem 30. That stem 30 passes through a release mechanism, preferably the firebox of a preferably electric furnace 34. When that electric furnace is energized, the stem is melted and severed. The envelope 22 with its contents are then free to drop down the bored shaft 14. Another release mechanism for severing the stem is to substitute (or add) an explosive device 98 to replace the electric furnace 34 to sever the stem. An alternative to the single round stem is to substitute several stems of conventional steel construction forms, such as xe2x80x9cIxe2x80x9d beams to act as multiple stems. In this case the severing devices are preferably explosive charges. This would allow the severance to occur simultaneously at each of the multiple stems. Returning to FIG. 1, adjacent to the bored shaft 14 are several levels of work areas 62. These provide access to the reactor for workers to control, maintain, replace fuel rods and the reactor, and to process the obsolete to be discarded fuel rods 70. These working areas are made accessible by elevator 66. The bottom work area processes the depleted discarded fuel rods which are dropped from the reactor 18. It houses a pulverizing machine 58 to reduce those fuel rods to fine granulated particles 74. These particles at the same time are mixed with very large proportions of filler, such as sand or earth. This will dilute their heat production and radiation to lower, preferably safe, acceptable levels. This mixture 158 is then preferably collected in a bag 134 and dropped to the bottom of the shaft 14. Above ground is a hopper 38 filled with fine grained dry sand 42. That hopper 38 channels the sand into a drainage pipe 46 which leads downward at an angle, emptying into the bored shaft 14. The sand in the pipe is held in place by a breakaway tear away gate 50. This gate is tied to the envelope 22 near its top by a cable 54. When the envelope 22 and its contents are dropped, the cable 54 tears away the breakaway gate 50, allowing the sand to flow out into the bored shaft 14 on top of the dropped enclosure 22. This layer of sand hopefully will be sufficient to contain any wayward radioactivity from a damaged reactor. Sand mixed with even a minute amount of dampness has a tendency to cake in place and will not flow freely. To insure that the sand moves along uninterrupted, measures must be taken to eliminate anything impeding the flow of the sand through the drainage pipe 46 and the hopper 38. An enlarged diameter of the drainage pipe 46 would help. Also all units containing the sand must have their contact surfaces coated with a waterproof sealant to keep out the moisture. These units would include the breakaway tear away gate 50, the interior of the drainage pipe 46 and the contact surfaces of the cement hopper 38. A waterproof covering of the sand stored in the hopper 38 must be provided. Also, the vertical surface walls of the bored shaft 14 must be coated with a waterproof sealant 118 to a depth below the ground water. This will eliminate the possibility of contaminating the ground water with radioactivity. The sand 42 should be kiln dried before it is put into this system to eliminate moisture. Gravel or pebbles may be substituted for the sand 42. A system of many ball shaped wire brushes 162 may preferably be located along the path of the flowing sand 42. These wire brushes should be tied to the breakaway tear away gate 50 and to the other wire brushes 162 by several long, coiled (with much slack) steel cables 122. The wire brushes 162 will preferably vary in size. They would be small at the lower end and will gradually get larger at the upper end in the hopper 38. This will break up any caking of the sand and aid the free flowing of that sand. An alternative or supplement to the wire brushes 162 are spring steel fingers 86 shown in FIG. 2. They will pass through and loosen the sand 42. These steel fingers should vary in size. The steel fingers mounted at the lower end would be smaller. The steel fingers at the upper end in the hopper would be larger. After the enclosure 22 and its contents have been released to fall to the bottom of the bored shaft 14, the hopper 38 can then be used as a funnel to direct earth fill from a giant power shovel or bulldozer. When the bored shaft 14 is filled with earth up to a short distance below ground level 10, the steel support structure above ground 170 may be removed and scrapped. This steel structure will not be radioactive. Then the concrete foundation 82 may be broken up and dropped down the shaft 14. The unfilled open bored shaft may then be completely filled with earth fill. Nuclear reactors vary in size depending on their individual uses. Note the mini-reactors used in submarines and spacecraft. On the other hand there is nothing limiting the size of the reactor and its envelope. It can be large enough to accommodate almost any size desirable. For use in an electric generating plant a medium size reactor with its heat exchanger and structure could be in the range of 4,000 tons (3,628 metric tons). This is the size of a small ocean going freighter. The steel stem would preferably be 39 inches (100 centimeters) in diameter. The diameter of the bored shaft would preferably be approximately 60 feet (approximately 18.28 meters). The depth of the bored shaft would preferably be approximately 1200 feet (approximately 365.76 meters). This depth could vary depending on the type of nuclear reactor fuel, the makup of the subsoil and the opinions of nuclear engineers at each installation. A thick cap 182 of concrete may be added for more protection from above ground attack or underground accidental rupture, similar to a conventional containment vessel. Preferably, the nuclear reactor is installed from directly above. FIG. 3 is a cross section showing the reinforced concrete foundation 82 mounted at the top of the bored shaft 14. This is required to support the entire weight of the reactor and its supporting structure. Also shown is a cross section of the hopper 38 and its drainage pipe 46 which would be installed at the same time. FIG. 4 is a view looking down at the circular reinforced concrete foundation 82. This shows the contour required to incorporate the concrete hopper 38. FIG. 5 is a cross section of the welded steel preliminary support structure 170 mounted on the foundation 82 over the bored shaft 14 adjacent to the drainage pipe 46 and the hopper 38. FIG. 6 is a view from above and looking down at the steel preliminary support structure 170. It has an opening in the center over the bored shaft 14 down through which all of the reactor and its main support structure has to be lowered by crane, one piece at a time. FIG. 7 is a cross section of the envelope 22 and its contents, the heat exchanger 26 and the reactor 18. This diagram shows how the envelope 22 is suspended from the steel preliminary support structure 170. The envelope 22 suspended in the bored shaft 14 is larger than the opening above. All of the structure and equipment below must be fabricated in sections small enough to be lowered through the access opening above and assembled in place. Work must be started at the top of the envelope by installing the top sections piece by piece. The assembly will preferably progress downward section by section until the nose section at the bottom is complete. The section of the envelope 22 contacting the concrete foundation 82 is preferably tilted inboard approximately 5xc2x0 from the vertical to give positive clearance on separation during the envelope drop. The tilted surface will preferably bear on the concrete foundation 82, giving lateral support and stability to the whole suspended unit during its years of working lifetime. Preferably vertical ribs 94 give added strength to the upper section of the envelope 22. They play an important part in the separation of the envelope 22 (with its contents) from the steel preliminary support structure 170 above ground level 10. The heat exchanger 26 and the atomic reactor 18 (without its nuclear fuel rods) must be lowered by crane through the opening at the top piece by piece (or subassembly by subassembly) and installed in place. FIG. 8 is a cross section of a welded plug assembly. Its function is to permanently attach the suspended envelope to the preliminary steel support structure. The plug assembly consists of a lower plug support structure 102, a steel stem 30, an explosive charge mount 98, an electric furnace 34 and an upper plug support structure 106. The steel stem 30 is preferably a solid forged steel rod shaped member designed to be melted and severed when the need arises. It also supports the electrical furnace 34 and the explosive charge mounting 98. The electric furnace 34 consists of a steel supporting structure, a brick firebox, blowers and heating elements. It is preferably round in shape and preferably completely encircles the steel stem. This provides uniform heating to the outside surface of the stem when the need arises. The top horizontal surface of the steel supporting structure of the electric furnace is attached by welding to the steel stem. The bottom horizontal surface of the steel supporting structure of the electric furnace is unattached and is free to slide up and down the steel stem. This results in a slip fit with the steel stem when it is severed by melting. The explosive charge mount 98 is a structure that encircles the steel stem 30. Its function is to support a high explosive charge to sever the steel stem 30. This is a backup feature in case the electric furnace is damaged and cannot function. The actual explosive charge will normally be stored underground a safe distance away. It would be installed only when actually needed. It would be dangerous and unreliable to be installed in place below the furnace for long periods of the reactor""s working lifetime. FIG. 9 is a view of the plug assembly viewed from above and looking down at the assembly 106 and stem 30. FIG. 10 is a view of the plug assembly viewed from below and looking up at that assembly 102 and stem 30. FIG. 11 is a view looking down at the top of the plug assembly showing a single round bar stem. FIG. 12 is a view looking down at the top of the plug assembly showing a double xe2x80x9cIxe2x80x9d beam stem. FIG. 13 is a view looking down at the top of the plug assembly showing a quadruple xe2x80x9cIxe2x80x9d beam stem. FIG. 14 is a cross section showing how the plug assembly is inserted into the completed part of the installation. The completed part of the installation includes the bored shaft 14 at ground level 10 with the concrete foundation 82. This is the base for the preliminary steel support 170 holding the envelope 22 with its contents. The plug assembly includes the lower plug support structure 102, which has a cavity 110 (see FIG. 15), the explosive charge mount 98, the electric furnace 34, the steel stem 30 and the upper plug support structure 106. This is only a conceptual diagram because the plug assembly will have to be installed piecemeal to fit down through the access opening on top. FIG. 15 is a cross section of the invention after the plug assembly has been installed and the reactor is ready for the insertion of fuel rods and activation. Assembly is accomplished as follows: first, the envelope 22 and its contents are suspended from vertical stiffener ribs 94 of the welded preliminary support structure 170 shown in FIG. 5. The next step is to install the welded plug assembly shown in FIG. 8. This is assembled and installed in pieces and sub assemblies small enough to pass down through the opening at the top of the envelope 22. Now the weight of the envelope and its contents are supported by a duplicate structure up through the steel stem 30 into the welded preliminary support structure 170. The cavity 110 is filled with concrete. This, when coupled with the concrete foundation 82 will result in a complete concrete protective cover over the entire suspended reactor installation. The envelope 22 and its stiffener ribs 94 are then cut, in the area indicated 78, with an acetylene cutting torch, completely around the periphery of the envelope 22. This will result in all of the weight of the envelope 22 and its contents (the reactor 18 and the heat exchanger 26) being suspended from the stem 30. The upper area 174 of the plug assembly will be preferably filled with sand. A cap 182 of concrete will be preferably added on top of the installation. This will give added protection from any airborne or ground level bomb attack. The thickness of the cap 182 can be increased to whatever degree of protection is desired. An access passageway 178 must be installed from the top surface of the cap 182 down to above the cavity 110 in the plug assembly (which has been filled with concrete). This will provide access to monitor and maintain the electric furnace 34, to install the explosive charge in its structure 98 and to provide passageway for the steam lines, the water feed lines and the electrical supply lines to the reactor. All of these lines must have designs that would allow them to be manually disconnected or to be automatically disconnected when the envelope 22 is dropped. FIG. 16 shows the process that pulverizes the spent depleted fuel rods and mixes them with a very large proportion of sand or earth. This eliminates their heat production and reduces their radiation level. All of these operations can be monitored and controlled remotely from above ground level. First the spent fuel rods 70 are dropped from the envelope 22 through their exit chute 126. They then fall into the sand blasting machine hopper 130. Next they are fed into the sand blasting machine 58. The spent fuel particles coming from the sandblaster are mixed with sand and dropped into a large preferably fabric bag 134. This bag has a small remotely controlled explosive device 138 in the bottom. The bag preferably has a drawstring closure 142 at the top. A steady stream of sand or earth is released from the ground level and dropped down the supply pipe 146 during the pulverizing process to fall to the bottom of the bored shaft 14. A steady stream of this material can be assured by being fed from ground level by an auger feed or a stream of compressed air. When a fuel rod is completely pulverized the bag 134 is closed by its draw string 142 and dropped to the bottom of the bored shaft 14. The impact of the bag 134 hitting the bottom will cause it to rupture spreading the mixture over the bottom. When the falling earth from above covers the spread mixture to a sufficient depth the remotely controlled explosive device 138 is activated. The small explosion further spreads the radioactive particles. As more earth falls, more insulation is added to the material at the bottom of the bored shaft. Another method of pulverizing the spent fuel rods is to use a grinder in place of the sandblaster. The bag 134 collects all of the fuel rod particles and carries all of the radiation to the bottom of the shaft. It does not contaminate the walls of the bored shaft near ground level. Before the envelope 22 and its contents are dropped to their safe burial, it is desirable but not absolutely necessary to eject all fuel rods from the reactor and to process them to reduce their radiation. If an emergency does not allow the time to do this processing, the envelope can be dropped with the reactor fuel rods still in place. FIG. 17 shows the pulverizing machine 58 in the retracted position when not in use. In this position it is clear of the envelope 22 when it is dropped. Preferably, it is mounted on two rails on the floor and two rails in the ceiling. The unit may be extended to process the spent fuel rods and may be withdrawn when not in use. Preferably, the sand blaster hopper 130 fits inside the ceiling of its work area 62. The bag 134 has hit bottom and ruptured, spreading its mixture even more. More earth fill is falling from the supply pipe 146. The remotely actuated explosive device 138 is triggered adding more mixing and providing more insulation. Any part or all of the pulverizing machine 58 may be rolled out and dropped down the shaft if it becomes radioactive. A new replacement must be installed. The unit is expendable. FIG. 18 is an alternative version of processing the spent fuel rods 70. They will be pulverized by either the sandblasting or grinder method. The particles are dropped into the shaker mixing box 154 (attached to the pulverizing machine 58). Also flowing into this box through a pipe 150 from ground level 10 is an earth filler or sand material. This will allow a much larger proportion of filler relative to the proportion of spent fuel rod particles. This mixture 158 falls directly out of the bottom of the shaker mixing box 154 down the bored shaft 14 and ends up at the bottom of the shaft. This will result in a much lower radiation level because there is no limit to the proportion of earth filler added to the proportion of fuel rod particles. The final result would be a buried mixture with no heating properties and with radiation levels equal to the ore from which the fuel rods were mined, or at least with acceptable levels of heat and radiation. If an installation will process fuel from more than one nuclear plant, the bored shaft must be commensurately deeper to accommodate the extra volume of mixture. FIG. 19 is a cross section of the suspended reactor installation moments after the steel stem 30 has been severed by melting in the electric furnace 34. The envelope 22 containing the reactor 18 and the heat exchanger 26 has started its final drop. The fiberglass breakaway tear away sand gate 50 is torn away by the pull of the cable 54 attached to the envelope 22. The fine sand 42 starts to flow from the drainage pipe 46 into the bored shaft 14. The flow of the stream of sand 42 is assured by the action of the ball shaped round wire brushes 162, and their interconnecting cables 122 as they move along their path. This will break up any long time caking of the sand. FIG. 20 shows the reactor installation after the steel stem 30 has been severed. The envelope 22 with its contents, the reactor 18 and heat exchanger 26, have dropped to a permanent safe burial on top of the processed discarded fuel rods and its mixture 158. The drop of the envelope has caused the rupture of the breakaway tear away sand gate 50, allowing the sand 42 (in the drainage pipe 46 and hopper 38) to fall down the bored shaft 14 on top of the envelope 22. The sand 174 that filled the cavity above the concrete 110 in the plug assembly and surrounded the steel stem will be free to fall down the bored shaft 14. The fuel rod processing machine 58 is discarded by dropping it down the bored shaft 14. All of the steel structure remaining at the top of the bored shaft at ground level 10 must be removed and scrapped. It is not radioactive. Earth fill 166 is funneled down the hopper 38 until the bored shaft is filled to the bottom of the drainage pipe 46. The concrete foundation 82 is broken up and dropped down the bored shaft 14. The remaining portion of the bored shaft, the work areas and elevator are filled with earth fill 166. At the ground level 10 there is installed a bronze plaque 114 telling future generations of what lies buried beneath this spot. The present invention provides a wide latitude in locating the nuclear reactor relative to the other units of the electric generating plant. If a reactor becomes unusable for any reason it (as an independent interchangeable unit) can be replaced by a new unit at any reasonable distance away. The expensive turbines, generators, cooling towers and matrix of existing power grids are unaffected by radiation and can still be used. FIG. 21 is a separate installation incorporating the depleted waste fuel rod processing feature shown in FIG. 18. This installation should be located conveniently near the stockpile of waste fuel rods to be processed. This processing would render safe and harmless any dangerous waste fuel rods presently in storage or produced in the future worldwide. These processed waste fuel rods would be non-heat producing and with a low specified radiation level. The more dilute (with sand or loose earth) the lower the radiation level. The only limiting factor would be the expense of the filler and providing its underground disposal space. This separate installation is to be located over a small bored vertical shaft 186. That small bored vertical shaft is coated with a water proof sealant 118 down to a level below ground water. This assures that ground water is never contaminated by radiation. At ground level 10 over the small bored vertical shaft 186, there is installed the shaker mixing box 154 attached to the pulverizing machine 58. Also attached to the shaker mixing box 154 is a grinder attachment 190 and a waste fuel rod receiving hopper 130. The actual processing begins by inserting the to be processed depleted waste fuel rod 70 into the waste fuel rod receiving hopper 130. The grinder attachment 190 pulverizes the waste fuel rod 70. The resulting fuel rod particles 74 fall into the shaker mixing box 154. The shaker mixing box 154 thoroughly mixes the two substances and drops the mixture 158 down through the screened bottom of the box. That mixture ends up at the bottom of the shaft 186. When the desired number of rods are processed, the bored vertical shaft is plugged with loose earth. The installation is moved to its next location to process another series of waste fuel rods. The mobility of this unit eliminates the danger of accidents that can happen when transporting the fuel rods to a single disposal site. This invention may be used wherever it is desired to locate a nuclear reactor and to dispose of the resulting nuclear waste (including the reactor itself) without the necessity of transporting that waste.
	abstract	A linear accelerator head for use in a medical radiation therapy system can include a housing, an electron generator configured to emit electrons along a beam path, and a microwave generation assembly. The linear accelerator head may include a waveguide that is configured to contain a standing or travelling microwave. The waveguide can include a plurality of cells that are disposed adjacent one another, wherein each of the plurality of cells may define an aperture configured to receive electrons therethrough. The linear accelerator head can further include a converter and a primary collimator.
	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 cutoff 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.
040424545	description	DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention provides a method of producing homogeneous, striation-free doping of a Si body over its entire length and cross-section in a simple, rational (i.e. pre-calculable) and reproducible matter independent of the body diameter. By following the principles of the invention, it is practical to produce uniformly resistive n-type Si bodies having a resistivity greater than 30 ohm .times. cm and having an exact and homogeneous dopant distribution therein. The invention is based on the recognition that pure Si crystals may be rendered n-conductive by radiation thereof with thermal neutrons and provides for homogeneously distributing dopants and Si in such a manner that polycrystalline Si rods or bodies are freed from any donor material present therein by way of crucible-free zone melting in a suitable environment, such as in a vacuum or in a protective gas, and that the resultant polycrystalline rods are then transformed in a known manner to the monocrystalline state. The specific electrical resistivity of such monocrystalline rods, which at this stage is highly ohmic and may be n- or p-conductive, is then measured and the monocrystalline rods are then subjected to controlled radiation by thermal neutrons under time, intensity and location or target area parameters such that the desired n-conductivity is produced in the monocrystalline Si bodies. With a so-called radiogeneous doping of silicon in accordance with the nuclear reaction: EQU Si.sup.30 (n,.gamma.) Si.sup.31 .sup..beta..sup.- P.sup.31 the following simple computation is valid, presuming that the entire amount of Si.sup.31 is completely decayed and that the transmutation of Si.sup.30 is negligibly small: EQU N.sub.p = 1.7 .times. 10.sup.-.sup.4 .times. .phi. .times. t wherein N.sub.p is the phosphorous concentration in atoms/cm.sup.3 ; .phi. is the thermal neutron flow in neutrons/cm.sup.2 .times. sec.; and t is the radiation time in seconds. The invention includes the use of seed or nucleation crystals having a (111)-, (100)- or a (115)-orientation in transforming polycrystalline Si bodies into monocrystalline bodies. The use of such seed crystals facilitates the production of dislocation-free silicon by an additional zone-melting process prior to submitting the Si bodies to neutron radiation, even in the case of fairly large diameter rods. The invention also includes the rotation of the Si rods about the longitudinal axis thereof. Further, the invention includes subdividing the attained monocrystalline Si bodies into relatively smaller bodies, i.e. disks, before subjecting such disks to radiation by thermal neutrons. The production of a thermal neutron flow is known in the art and suitable core reactors of the light water moderated type or the graphite moderated type may be utilized as a radiation source. The single FIGURE schematically illustrates a zone melted dislocation-free (111)-oriented Si rod 1 undergoing radiation by thermal neutrons in a suitable operational environment O.sub.E. The neutron field or flux is schematically illustrated by the dots. (The behavior of thermal neutrons is considered analogous to a gas which fills the interior space of a Moderator.) As indicated on the drawing, the radiation target area, location or position is selected such that a lesser concentration of neutrons is present on a select portion of the body than on other areas of the body. In the embodiment shown, the concentration of neutrons is less in the area of the seed crystal 3 than on the remaining portions of the rod. The dots 2 show the greater concentration of thermal neutrons (and thus a greater extent of doping) while the dots 21 show a lesser concentration of thermal neutrons on the seed crystal 3. The curved double-headed arrow 4 schematically indicates the rotation of rod 1 about its longitudinal axis during the radiation step. With the foregoing general discussion in mind, an exemplary detailed embodiment is presented which will illustrate to those skilled in the art the manner in which the invention may be carried out. However, this embodiment is not intended and should not be construed as limiting the scope of the invention in any manner whatsoever. A polycrystalline Si rod having a rod length of 900 mm and a diameter of 35 mm is procured for use as a starting material. The specific resistivity of such polycrystalline rod is measured with the aid of a high frequency and comprises 550 ohm .times. cm, n-type. This rod is then subjected to a zone melt process in a vacuum environment and thereafter or simultaneously therewith, a seed crystal having a (111)-orientation is connected (by melting and solidification of adjacent surfaces) to the rod. This zone melting process transforms the rod into a zone melted monocrystalline rod which upon measurement has a specific resistivity of 1230 ohm .times. cm, n-type. After two further zone melting processes in a vacuum environment, the rod exhibits a specific resistivity of 2300 ohm .times. cm, p-type. Thereafter, the rod is subjected to a further zone melting process in a protective gas environment, such as argon, in order to convert the rod into a dislocation-free Si monocrystalline rod. During this further zone melting, the original rod diameter of 35 mm is changed to 55 mm by a known process, however, if desired, the original rod diameter may be maintained. This Si rod has a specific resistivity of a p-conduction type, which at the seed crystal end is 2500 ohm .times. cm and decreases to 2050 ohm .times. cm at the opposite end thereof. On the basis of the resistivity analysis, it is determined that the element boron is the prevalent p-impurity in the crystal. The concentration of boron corresponds to an amount in the range of about 4.6 .times. 10.sup.12 to about 6.6 .times. 10.sup.12 atoms of boron/cm.sup.3 of silicon. The desired n-doping in the Si monocrystalline rod is 130 ohm .times. cm, which corresponds to about 4 .times. 10.sup.13 atoms of phosphorous/cm.sup.3 of silicon. The neutron flow intensity in the reactor into which the rod is introduced is adjusted to 8 .times. 10.sup.13 neutron/cm.sup.2 .times. sec..sup.1 and the rod is subjected to this neutron flow for about 1 hour. A homogeneous doping, free of striations over the entire rod length is attained when the neutron flux is controlled in such a manner that the neutron concentration is about 5% lower in the area of the seed crystal of the monocrystalline body than in other areas of such body. In other words, the embodiment shown, the neutron flux is approximately 5% greater in the area of the original monocrystalline body (which showed up to 6.6 .times. 10.sup.12 atoms of boron/cm.sup.3 of silicon) than in the area of the seed crystal. The shape of the monocrystalline Si body being subjected to nuclear radiation is not critical and Si crystal disks, wafers, rods, etc. may be doped in accordance with the principles of the invention. The invention also includes heat-tempering the doped Si bodies after the neutron radiation step so as to eliminate any possible crystal lattice damage which may have occurred. Preferably, such heat-tempering takes place for about 1 hour in a silicon tube or furnace heated to temperatures above 1000.degree. C. However, this tempering process may be omitted if desired, particularly when the doped Si monocrystalline bodies are further processed or worked into semiconductor components and high-temperature conditions are involved in such further processing. When a silicon body having a specific resistivity of 15,000 to 18,000 ohm .times. cm, n-type is procured as a starting material, a specific resistivity of 120 ohm .times. cm target value may be obtained by the practice of the invention whereby 4.2 .times. 10.sup.13 atoms of phosphorous/cm.sup.3 are produced therein by way of neutron transmutation. Thereby, the specific resistivity (.rho.) fluctuation in the initial or starting body (about 30%) is decreased to approximately 0.3% in the final body. The invention thus provides for the first time a method of producing Si monocrystalline bodies having a relatively large diameter (greater than 30 mm) which are dislocation-free and without striations and having a homogeneous phosphorous doping therein so that resistivity (.rho.) fluctuations in axial and radial directions are less than about .+-.3%. Such doped Si monocrystalline bodies have a wide field of use and are particularly useful in the production of power rectifiers and thyristors operable with high currents and blockage voltages (for example, larger than 5000 V) while exhibiting an excellent avalanche behavior. The method of the invention is also advantageously used for the production of multidiodes (vidicons). It is thought that the invention and its advantages will be understood from the foregoing description and it is apparent that various changes may be made in the process, form, construction and arrangements of the parts without departing from the scope of the invention or sacrificing its material advantages, the forms hereinbefore described and illustrated in the drawing being merely preferred embodiments.
	abstract	Disclosed is a correction container of a Marinelli, wherein a first groove is formed in the lower portion of the container body formed with a diameter corresponding to the inner diameter of the lower surface of the Marinelli beaker, to be attached to a detector of a detecting system for nuclide analysis, a second groove having a diameter smaller than that of the first groove is formed on the upper portion, and an intake and exhaust hole is formed through the first groove to the second groove.
	claims	1. A control rod for nuclear reactors comprising:four wings including neutron absorbing hafnium;a front end structural member which has a cross shape in cross section and includes brackets bonded to leading ends of the wings; anda terminal end structural member which has a cross shape in cross section and includes brackets bonded to tailing ends of the wings, whereinthe four wings are bonded to a wing bonding member including a cross-shaped center shaft so as to form a cross shape in such a manner that the wings are spaced from each other at predetermined intervals in an axial direction,at least the front end structural member and the wing bonding member are made of a zirconium alloy containing hafnium of which the hafnium content is greater than or equal to that of natural compositions,the wings have principal portions including neutron absorbing plates having neutron absorbing portions, each of the wings has an outer surface which is configured to be opposed to a fuel assembly, and each of the wings includes a composite member that includes a hafnium plate or a hafnium-zirconium alloy plate diluted by zirconium and a zirconium plate that is of pure zirconium, the zirconium plate covering the outer surface of each wing that is configured to be opposed to the fuel assembly, andthe neutron-absorbing plates are opposed to each other in such a manner that trap spaces in which reactor water is present are disposed between the neutron absorbing plates, and a thickness of each neutron absorbing plate is substantially uniform in a direction in which the control rod is inserted or withdrawn. 2. The control rod according to claim 1, further comprising tie rods, disposed in the wings, for connecting the front end structural member and the terminal end structural member to each other, wherein the neutron-absorbing plates are mounted in the wings so as to slide from the leading ends toward the tailing ends of the wings or from the tailing ends toward the leading ends of the wings. 3. The control rod according to claim 2, wherein the tie rods are made of hafnium. 4. The control rod according to claim 1, further comprising wing end reinforcing members which are disposed in the trap spaces between the neutron absorbing plates and which slides in the axial direction of the control rod. 5. The control rod according to claim 4, wherein the wing end reinforcing members are made of hafnium. 6. The control rod according to claim 1, wherein each of the neutron absorbing portions has a first portion extending from the leading end of the neutron-absorbing portion and having a length equal to 1/24 to 2/24 of a length of the neutron absorbing portion, a second portion extending from the first portion and having a length equal to a difference obtained by subtracting the length of the first portion from ¼ to ½ of the length of the neutron absorbing portion, and a third portion extending from the tailing end of the neutron absorbing portion, in which the second portion has a width greater than that of the third portion, and an outer end of a leading portion of each wing is aligned with that of a tailing portion of the wing. 7. The control rod according to claim 6, wherein the first portion has a width less than that of the second portion. 8. The control rod according to claim 1, further comprising a hafnium-zircaloy composite material and short narrow hafnium rods, wherein the hafnium-zircaloy composite material is repeatedly mount-folded and valley-folded so as to provide mount-folded and valley-folded portions which are arranged at equal intervals and which extend in parallel to each other, the valley-folded folded portions are brought close to each other so that the folded hafnium-zircaloy composite material has a cross shape in horizontal cross section, and the hafnium rods are arranged in end portions of the wings in form of spacers. 9. The control rod according to claim 8, further comprising a tie cross made of zircaloy, wherein the valley-folded portions partially have longitudinal holes regularly and intermittently arranged in the axial direction and portions of the tie cross are arranged above and below the longitudinal holes so as to maintain the cross shape and improve mechanical strength. 10. The control rod according to claim 1, further comprising short narrow hafnium rods functioning as spacers, wherein the four composite members are bent so as to provide an L-shape, bent portions of the composite members are brought close to each other so as to be directed to a center of a cross shape, and the hafnium rods are attached to end portions of the bent composite members. 11. The control rod according to claim 10, further comprising a tie cross made of zircaloy, wherein the bent portions partially have longitudinal holes regularly and intermittently arranged in the axial direction and portions of the tie cross are arranged above and below the longitudinal holes so as to maintain the cross shape and improve mechanical strength. 12. The control rod according to claim 1, wherein each wing is formed so that two of the composite members are opposed to each other with a space therebetween and spacers for keeping spaces are fixed to both ends of the composite members in an inserting or withdrawing direction and a perpendicular direction, and the four wings are bonded to a tie cross including a cross-shaped center shaft so as to form a cross shape in such a manner that the wings are spaced from each other at predetermined intervals in the axial direction. 13. The control rod according to claim 1, wherein each wing is formed so that one of the composite members is bent so as to provide a U-shape with a space, and a plurality of short spacers are fixed to end portions of the bent composite member located on the side close to a cross-shaped center shaft included in a tie cross, the tie cross is spaced from the wing at a predetermined distance in the axial direction, and the four wings are bonded to each other so as to form a cross shape. 14. The control rod according to claim 1, wherein each wing is formed so that one of the composite members is bent so as to provide a cylindrical shape, both end portions of the bent composite member are bonded to each other to form a cylinder, which is then pressed into a flattened tube, and a plurality of short spacers are fixed to outer end portions and inner portions of the flattened tube, the inner portions being located on the side close to a cross-shaped center shaft, which is included in a tie cross, and the four wings are bonded to form a cross shape so that the tie cross is spaced from the wings at a predetermined distance in the axial direction. 15. The control rod according to claim 1, wherein the wings are fixed with members, located in a vicinity of end portions of the cross-shaped center shaft for preventing the wings from being opened. 16. The control rod according to claim 1, wherein spacers, made of hafnium, disposed in the outer end portions of the wings are short rods and center portions of the short rods are fixed to the composite members. 17. The control rod according to claim 1, whereineach of the zirconium plates has a thickness in the range of approximately 0.2 to 0.5 millimeters, andeach of the composite members has a thickness in the range of approximately 2 to 2.5 millimeters. 18. The control rod according to claim 1, wherein each of the composite members includes another different zirconium plate, the zirconium plate and the another different zirconium plate sandwiching the hafnium plate or the hafnium-zirconium alloy plate. 19. A control rod for nuclear reactors comprising:four wings including neutron absorbing hafnium;a front end structural member which has a cross shape in cross section; anda terminal end structural member which has a cross shape in cross section, whereinthe four wings are bonded to a wing bonding member including a cross-shaped center shaft so as to form a cross shape in such a manner that the wings are spaced from each other at predetermined intervals in an axial direction,at least the front end structural member and the wing bonding member are made of a zirconium alloy containing hafnium of which the hafnium content is greater than or equal to that of natural compositions,the wings have principal portions including neutron absorbing plates having neutron absorbing portions, each of the wings has an outer surface which is configured to be opposed to a fuel assembly, and each of the wings includes a composite member that includes a middle plate, which is a hafnium plate or a hafnium-zirconium alloy plate diluted by zirconium, a first zirconium plate, and a second zirconium plate, the first zirconium plate being bonded to a top surface of the middle plate, and the second zirconium plate being bonded to a bottom surface of the middle plate, the top surface and the bottom surface of the middle plate being covered by the first and second zirconium plates, respectively, without side surfaces of the middle plate being covered by zirconium plates, and the first zirconium plate covering the outer surface of each wing that is configured to be opposed to the fuel assembly, andthe neutron-absorbing plates are opposed to each other in such a manner that trap spaces in which reactor water is present are disposed between the neutron absorbing plates, and a thickness of each neutron absorbing plate is substantially uniform in a direction in which the control rod is inserted or withdrawn.
	summary
050531905	summary	The present invention primarily relates to integral water cooled nuclear reactors with pressurisers, and is particularly applicable to water cooled nuclear reactors of the integral pressurised water reactor (PWR) type and the integral indirect cycle boiling water reactor (BWR) type with integral pressurisers. However the invention is also applicable to integral water cooled nuclear reactors with separate pressurisers and to dispersed PWR's with separate pressurisers. The present invention is particularly suitable for use with light water, the invention is also applicable for use with heavy water moderated water cooled reactor types. A problem associated with integral pressurised water reactors (PWR's) of the saturated self pressurised type is that the reactor cores have a certain amount of boiling in the moderator/coolant to make up for heat losses from the pressuriser and due to non-uniformity in the distribution of cooling across the reactor core. Perturbations in the boiling voidage can cause unwanted disturbances in power level and flow distribution in the reactor core. Also, the transient and steady state pressure of the reactor coolant can be affected by variations in the patterns and levels of boiling voidage. In the prior art voidage has been controlled by means of an external pressuriser. In contrast to pressurised water reactors (PWR's), boiling water reactors (BWR's) are designed to operate with substantial amounts of boiling voidage in their reactor cores. But unlike PWR's in which an intermediate heat exchanger or steam generator is used to raise steam for an indirect turbo-generator Rankine cycle, in most BWR power plants the steam raised in the reactor core is ducted to the turbo-alternator in a direct Rankine cycle arrangement. A disadvantage of the direct cycle arrangement is that the working fluid passing through the turbine, condenser and feed system of the power plant is slightly radioactive. An alternative arrangement is to provide within the steam space of the boiling water reactor pressure vessel, an intermediate heat exchanger or steam generator, as in the integral PWR. However, in the indirect cycle BWR case steam vapour from the reactor core condenses on the primary circuit side of the intermediate heat exchanger steam generator and is returned directly to the reactor core without leaving the reactor pressure vessel. As with a dispersed PWR pressure control and transient coolant inventory control in an integral PWR could be effected by means of an external or integral pressuriser which communicates with the primary circuit through a surge pipeline. However a simple pressuriser/surgeline arrangement could not be employed with an indirect cycle BWR as it is intrinsically unstable. A slight excess of reactor core power over steam demand power would cause the pressuriser to flood. In the case of a PWR the simple pressuriser/surge line arrangement is meta-stable. Here the pressuriser is maintained at a higher temperature than in the reactor pressure vessel and reactor core and a large excess of reactor core power over steam demand is required to cause the pressuriser to flood and the reactor pressure vessel or primary circuit and reactor core to become blanketed in steam. A further problem with water cooled reactors is that under some accident conditions the supply of coolant to the reactor core can be suddenly impaired or lost, resulting in severe reactor core damage in a timescale shorter than can be prevented by engineered safety systems of the prior art. The present invention seeks to provide an integral pressuriser for integral PWR's for controlling the unwanted effects of variation of in core voidage in self pressurised integral PWR's under steady state and transient conditions. The present invention also seeks to provide an integral pressuriser for integral indirect cycle BWR's for controlling primary pressure, primary water level in the steam generator and the degree of boiling in the reactor core under steady state and transient conditions. The present invention also seeks to provide an integral pressuriser for integral PWR's and indirect cycle BWR's which is absolutely stable in normal, upset and accident conditions. The present invention also seeks to provide an external pressuriser for integral PWR's and indirect cycle BWR's which is absolutely stable under normal, upset and accident conditions. The present invention further seeks to provide a reserve supply of coolant immediately and continuously available, to the primary circuit and reactor core under the action of gravity, and a means for preventing steam blanketing of the primary circuit and reactor core during accident conditions. The present invention also seeks to provide a low cost water cooled nuclear reactor power plant in low and moderate power ratings. Accordingly the present invention provides a water cooled nuclear reactor and pressuriser assembly comprising a reactor core, a pressuriser, a primary water coolant circuit arranged to cool the reactor core, the reactor core and at least a portion of the primary water coolant circuit being enclosed by a pressure vessel, the pressuriser having a water space and a steam space, at least a portion of the water space of the pressuriser being positioned above an upper portion of the primary water coolant circuit, at least one means which communicates between the pressuriser and the primary water coolant circuit to connect the steam space of the pressuriser with the upper portion of the primary water coolant circuit, at least one surge port means which communicates between the pressuriser and the primary water coolant circuit to connect the water space of the pressuriser with a portion of the primary water coolant circuit positioned below any normal effective water level range in the primary water coolant circuit, the at least one surge port means being arranged to have relatively low flow resistance for water from the water space of the pressuriser to the primary water coolant circuit and relatively high flow resistance for water from the primary water coolant circuit to the water space of the pressuriser whereby the at least one means which communicates between the steam space of the pressuriser and the upper portion of the primary water coolant circuit allows excess vapour formed in the primary water coolant circuit to flow to the steam space of the pressuriser to increase the stability of the assembly. The reactor core, the primary coolant circuit and the pressuriser may be arranged as an integral unit enclosed by the pressure vessel, at least one casing arranged in the pressure vessel to substantially divide the pressure vessel into a first chamber and a second chamber, the reactor core and the primary coolant circuit being arranged in the second chamber, the pressuriser being arranged in the first chamber, the casing preventing interaction between the water in the primary water coolant circuit and the water in the water space of the pressuriser. The reactor core may be arranged in the lower region of the lower chamber, the primary coolant circuit comprising a riser passage to convey relatively hot water and steam to at least one heat exchanger, and a downcomer passage to convey relatively cool water from the at least one heat exchanger to the reactor core. The riser passage may be defined by a hollow cylindrical member, the downcomer passage being defined between the hollow cylindrical member and the pressure vessel. The at least one heat exchanger may be positioned in an upper region of the downcomer passage. The at least one surge port means may comprise a hydraulic diode. The casing may comprise an annular member which extends downwards from the peripheral region thereof, an annular passage being formed between the annular member of the casing and the pressure vessel for the flow of water from the water space of the pressuriser to the primary coolant circuit and from the primary coolant circuit to the steam space of the pressuriser. The pressuriser may form a surge tank positioned in the first chamber, the surge tank being defined by the pressure vessel and the casing. The casing may comprise an annular member which extends downwards from a peripheral region thereof, the annular member being secured to the pressure vessel to form an annular lower portion of the surge tank with the pressure vessel. The casing may comprise a bottom member positioned below the reactor core, the casing dividing the pressure vessel into a first outer chamber and a second inner chamber, the second inner chamber being substantially defined by the casing. A peripheral region of the casing may be secured to the pressure vessel, the casing may be arranged to divide the pressure vessel into a first vertically upper chamber and a second vertically lower chamber. The at least one surge port means may connect a lower portion of the water space of the surge tank with the primary water coolant circuit in the region of the reactor core. The at least one surge port means may connect the lower portion of the water space of the surge tank with the primary water coolant circuit below the reactor core. The riser passage may be defined by a hollow cylindrical member, the downcomer passage being defined between the hollow cylindrical member and the casing. The pressuriser may be a separate pressuriser. The at least one surge port means may connect a lower portion of the water space of the surge tank with a lower portion of the downcomer passage in the region of the heat exchanger. The at least one surge port means may connect a lower portion of the water space of the surge tank with a lower portion of the downcomer passage below the heat exchanger. The at least one surge port means may comprise a re-entrant nozzle. The at least one surge port means may comprise a hydraulic diode. The at least one means which communicates between the pressuriser and the primary coolant circuit may comprise at least one pipe which interconnects at least one port in the casing with the steam space in the pressuriser. The casing may comprise an annular member which extends downwards from a central region thereof, a peripheral region of the casing may be sealingly secured to the pressure vessel, the annular member may be sealed at its lower end to form a lower portion of the surge tank. At least one of the means which communicate between the pressuriser and the primary water coolant circuit may comprise a spray nozzle. At least one of the means which communicate between the pressuriser and the primary water coolant circuit may connect the steam space of the pressuriser with the primary water coolant circuit above the heat exchanger. The water cooled nuclear reactor may be an integral pressurised water reactor. The pressuriser may have heating means to heat the water in the water space. The water cooled nuclear reactor may be an integral indirect cycle boiling water reactor, the at least one means which communicates between the steam space of the pressuriser and the upper portion of the primary water coolant circuit controlling the effective water level in the primary water coolant circuit.
046506390	abstract	The invention concerns a method and apparatus for eliminating leakage spaces between the partitions (1) surrounding the core of a pressurized water nuclear reactor, after it is brought into operation.. Operations are carried out under water, during shutdown of the reactor. The defective joins (12) between the partitions (1) are identified. For each join, the partitions (1) are pierced, the hole inside a partition (1) is screw-threaded, the swarf is recovered, a screw with diametrical expansion is introduced and screwed into the hole and the screw is expanded by displacement of a rod in the longitudinal direction of the screw. Moving location, the operations are repeated for each defective join (12). The apparatus comprises a case (25) containing a drum (36) bearing tools for boring (54-65), screw-threading, and screwing, a cleaning tube and a punch for locking the screw.. The invention is applicable to work on pressurized water nuclear reactors, after they have been brought into operation.
043081010	abstract	The present invention relates to an improved attachment assembly for clamping a nuclear reactor foot ring into engagement with a surrounding support wall while allowing for thermal expansion of the foot ring.
	description	Notice: More than one reissue application has been filed for the reissue of U.S. Pat. No. 6,510,202. The reissue applications are application Ser. No. 11/039,457 (the present application) and Ser. No. 11/039,456, all of which are divisional reissues of US Pat. No. 6,510,202. The present invention relates to an imaging apparatus, imaging method, and computer-readable storage medium which stores processing steps in executing the method, which are used for, e.g., an apparatus or system for performing radiation imaging of an object using a grid. Conventionally, a radiation method of irradiating an object with radiation such as X-rays and detecting the intensity distribution of the radiation transmitted through the object to acquire the radiation image of the object is widely used in the field of industrial non-destructive inspection or medical diagnosis. In the most popular radiation imaging method, a combination of a so-called “screen” which emits fluorescent light by radiation and a silver halide film is used. In the above radiation imaging method, first, an object is irradiated with radiation. The radiation transmitted through the object is converted into visible light by the screen to form a latent image on the silver halide film. After that, the silver halide film is chemically processed to acquire a visible image. A thus obtained film image (radiation image) is a so-called analog picture and is used for medical diagnosis or inspection. A computed radiography apparatus (to be referred to as a “CR apparatus” hereinafter) which acquires a radiation image using an imaging plate (to be referred to as an “IP” hereinafter) coated with a stimulable phosphor as a phosphor is also being put into practice. When an IP primarily excited by radiation irradiation is secondarily excited by visible light such as a red laser beam, light called stimulable fluorescent light is emitted. The CR apparatus detects this light emission using a photosensor such as a photomultiplier to acquire a radiation image and outputs a visible image to a photosensitive material or CRT on the basis of the radiation image data Although the CR apparatus is a digital imaging apparatus, it is regarded as an indirect digital imaging apparatus because the image formation process, reading by secondary excitation, is necessary. The reason for “indirect” is that the apparatus cannot instantaneously display the radiation image, like the above-described apparatus (to be referred to as an “analog imaging apparatus” hereinafter) which acquires an analog radiation image such as an analog picture. In recent years, a technique has been developed, which acquires a digital radiation image using a photoelectric conversion device in which pixels formed from small photoelectric conversion elements or switching elements are arrayed in a matrix as an image detection means for acquiring a radiation image from radiation through an object. Examples of a radiation imaging apparatus employing the above technique, i.e., having phosphors stacked on a sensor such as a CCD or amorphous silicon two-dimensional image sensing element are disclosed in U.S. Pat. Nos. 5,418,377, 5,396,072, 5,381,014, 5,132,539, and 4,810,881. Such a radiation imaging apparatus can instantaneously display acquired radiation image data and is therefore regarded as a direct digital imaging apparatus. As advantages of the indirect or direct digital imaging apparatus over the analog imaging apparatus, a filmless system, an increase in acquired information by image processing, and database construction become possible. An advantage of the direct digital imaging apparatus over the indirect digital imaging apparatus is instantaneity. The direct digital imaging apparatus can be effectively used on, e.g., a medical scene with urgent need because a radiation image obtained by imaging can be immediately displayed at that place. When the radiation imaging apparatus described above is used as a medical apparatus to detect the radiation transmission distribution of a patient as an object to be examined, a scattering ray removing member called a “grid” is normally inserted between the patient and a radiation transmission distribution detector (to be also simply referred to as a “detector” hereinafter) to reduce the influence of scattering rays generated when radiation is transmitted through the person to be examined. A grid is formed by alternately arranging a thin foil of a material such as lead which hardly passes radiation and that of a material such as aluminum which readily passes radiation perpendicularly to the irradiation direction of radiation. With this structure, radiation components such as scattering rays in the patient, which are generated when the patient is irradiated with radiation and have angles with respect to the axis of irradiation, are absorbed by the lead foil in the grid before they reach the detector. For this reason, a high-contrast image can be obtained. If the grid stands still during imaging, the radiation reaching the lead in the grid is wholly absorbed including both the scattering rays and the primary rays of radiation. Since a distribution difference distribution corresponding to the array in the grid is formed at the detection section, a striped radiation image is detected, resulting in inconvenience in reading at the time of image diagnosis or the like. A radiation imaging apparatus having a mechanism for moving the grid during imaging has already been placed on the market. However, in the above-described conventional radiation imaging apparatus having a grid, a light receiving scheme using a sensor such as a CCD or amorphous silicon two-dimensional image sensing element is not used, and a signal read by a two-dimensional solid-state image sensing element is real-time electrical processing. For this reason, unlike an analog imaging apparatus or an indirect digital imaging apparatus such as a CR apparatus, the influence of vibration of the imaging section or the electromagnetic influence of the driving motor due to grid movement poses a problem. More specifically, the vibration of the imaging section due to grid movement also vibrates the capacitor and signal lines. The weak electric capacitance varies, and noise is superposed on the radiation image. Additionally, in the signal read by the sensor, when the motor is driven near the sensor to move the grid, the signal potential or control power supply potential varies due to the influence of electromagnetic noise, and noise is superposed on the radiation image. The radiation image with noise superposed thereon may deteriorate, e.g., the medical diagnostic performance. On the other hand, in the sensor such as a two-dimensional solid-state image sensing element, the amount of charges accumulated in the sensor increases in proportion to the signal accumulation time due to the influence of a dark current even in an unexposed state. The larger the amount of charges that do not contribute to an image signal becomes, the larger the noise added to the output image signal becomes. Hence, imaging control is preferably optimized to make the accumulation time in the sensor as short as possible while eliminating the influence of grid vibration. Neither an apparatus nor system that implement such control are conventionally available. In the conventional X-ray imaging apparatus, an X-ray beam is projected from an X-ray source through an object such as a medical patient to be analyzed. After the X-ray beam passes through the object to be examined, normally, an image intensifier converts the X-ray radiation into a visible light image, a video camera generates an analog video signal from the visible image, and the video signal is displayed on a monitor. Since an analog video signal is generated, image processing for automatic luminance adjustment and image enhancement is performed in an analog domain. A solid-state X-ray detector having high resolving power has already been proposed, which is constructed by a two-dimensional array using 3,000 to 4,000 detection elements represented by photodiodes for each dimension. Each element generates an electrical signal corresponding to a pixel luminance of an X-ray image projected to the detector. The signals from the respective elements are individually read and digitized. Then, the signals are subjected to image processing, stored, and displayed. A medical X-ray image need needs to have 4,096 or more grayscale levels. In addition, since the X-ray dose is preferably suppressed to reduce the exposure amount, the image signal amount is also limited. For this reason, an extremely noise-free system is required as compared to a general image sensing element. In medical X-ray imaging, a grid is used to suppress the influence of X-ray scattering. A fixed grid is generally unsuitable to with a solid-state X-ray image sensing element and poses a problem of aliasing, a system may be built using a movable grid. As described above, a medical X-ray image sensing apparatus is required to be noise-free. A vibration caused by the movable grid can be a new noise source. The noise is generated by, e.g., the piezoelectric effect of a high-permittivity capacitor used in a circuit for generating a reference potential or simply because the parasitic capacitance in the read circuit varies due to the vibration. To obtain the highest image quality, grid drive control, X-ray detector movement control, and X-ray detector driving method must be appropriately executed. The present invention has been made to solve the above problem, and has as its object to provide an imaging apparatus, imaging method, and computer-readable storage medium which stores processing steps of executing the method, which can provide a high-quality image optimum for medical diagnosis or the like by an arrangement for preventing any degradation in image quality due to the influence of electromagnetic noise and vibration caused by grid movement. It is another object of the present invention to provide an imaging apparatus and method which can easily and reliably obtain a satisfactory image without any influence of vibration of a grid or X-ray detection means system by a very simple arrangement. In order to achieve the above objects, an imaging apparatus according to the first aspect of the present invention is characterized by the following arrangement. That is, there is provided an imaging apparatus which has a movable element related to imaging and an image sensing element, and has a function of sensing an image of an object with the image sensing element and reading as an image signal a signal generated by the image sensing element, comprising control means system for stopping moving movement of the element related to imaging, and after the stop of stopping the movement, starting reading the of a signal generated by the image sensing element. An imaging apparatus according to the second aspect of the present invention is characterized by the following arrangement. That is, there is provided an imaging apparatus which has a movable element related to imaging and an image sensing element, and has a function of sensing an image of an object with the image sensing element and reading as an image signal a signal generated by the image sensing element, comprising drive means system for moving the element related to imagingby the image sensing element, and control means system for controlling to cause the drive means system to operate the element related to imaging at a predetermined speed without any acceleration during an operation period related to a read reading a signal from the image sensing element. An imaging apparatus according to the third aspect of the present invention is characterized by the following arrangement. That is, there is provided an imaging apparatus which has a movable element related to imaging and an image sensing element, and has a function of sensing an image of an object with the image sensing element and reading as an image signal a signal generated by the image sensing element, comprising drive means system for moving the element related to imagingby the image sensing element, and control means system for controlling to cause the drive means system to operate the element related to imaging at a uniform acceleration during an operation period related to a read reading a signal from the image sensing element. An imaging apparatus according to the fourth aspect of the present invention is characterized by the following arrangement. That is, there is provided an imaging apparatus which has a movable element related to imaging and an image sensing element, and has a function of sensing an image of an object with the image sensing element and reading as an image signal a signal generated by the image sensing element, comprising drive means system for moving the element related to imagingby the image sensing element, and control means system for controlling to execute execution of a drive operation related to image acquisition upon determining that a value of a vibration is not more than a predetermined value during an operation period related to an image read from the image sensing element. An imaging apparatus according to the fifth aspect of the present invention is characterized by the following arrangement. That is, there is provided an imaging apparatus having a function of sensing an image of an object with an image sensing element and reading as an image signal a signal generated by the image sensing element, comprising drive means system for moving the image sensing element, and control means system for stopping moving movement of the image sensing element by the drive means system, and after the stop of stopping the movement, starting reading of an accumulated signal from the image sensing element. An imaging apparatus according to the sixth aspect of the present invention is characterized by the following arrangement. That is, there is provided an imaging apparatus having a function of sensing an image of an object with an image sensing element and reading as an image signal a signal generated by the image sensing element, comprising drive means system for moving the image sensing element, and control means system for controlling to cause the drive means system to operate the image sensing element at a predetermined speed without any acceleration during an operation period related to a read reading of a signal from the image sensing element. An imaging apparatus according to the seventh aspect of the present invention is characterized by the following arrangement. That is, there is provided an imaging apparatus having a function of sensing an image of an object with an image sensing element and reading as an image signal a signal generated by the image sensing element, comprising drive means system for moving the image sensing element, and control means system for controlling to cause the drive means system to operate the image sensing element at a uniform acceleration during an operation period related to a read reading a signal from the image sensing element. An imaging apparatus according to the eighth aspect of the present invention is characterized by the following arrangement. That is, there is provided an imaging apparatus having a function of sensing an image of an object with an image sensing element and reading as an image signal a signal generated by the image sensing element, comprising drive means system for moving the image sensing element, and control means system for controlling to execute execution of a drive operation related to image acquisition upon determining that a value of a vibration is not more than a predetermined value during an operation period related to an image read from the image sensing element. An imaging method according to the first aspect of the present invention is characterized by the following step. That is, there is provided an imaging method of sensing an image of an object with an image sensing element and reading a signal generated by the image sensing element while moving a movable element related to imaging, comprising the step of stopping moving movement of the element related to imaging, and after the stop of stopping the movement, starting reading the signal from the image sensing element. An imaging method according to the second aspect of the present invention is characterized by the following step. That is, there is provided an imaging method of sensing an image of an object with an image sensing element and reading a signal generated by the image sensing element while moving a movable element related to imaging, comprising the step of, in moving the element related to imaging at the time of image sensing by the image sensing element, controlling to operate operation of the element related to imaging at a predetermined speed without any acceleration during an operation period related to a read of the reading a signal from the image sensing element. An imaging method according to the third aspect of the present invention is characterized by the following step. That is, there is provided an imaging method of sensing an image of an object with an image sensing element and reading a signal generated by the image sensing element while moving a movable element related to imaging, comprising the step of, in moving the element related to imaging at the time of image sensing by the image sensing element, controlling to operate operation of the element related to imaging at a uniform acceleration during an operation period related to a read of the reading a signal from the image sensing element. An imaging method according to the fourth aspect of the present invention is characterized by the following step. That is, there is provided an imaging method of sensing an image of an object with an image sensing element and reading a signal generated by the image sensing element while moving a movable element related to imaging, comprising the step of, in moving the element related to imaging at the time of image sensing by the image sensing element, controlling to execute execution of a drive operation related to image acquisition upon determining that a value of a vibration of the image sensing element is not more than a predetermined value during an operation period related to an image read from the image sensing element. An imaging method according to the fifth aspect of the present invention is characterized by the following step. That is, there is provided an imaging method of sensing an image of an object with a movable image sensing element and reading a signal generated by the image sensing element, comprising the step of stopping moving movement of the image sensing element, and after the stop of stopping the movement, starting reading the of a signal from the image sensing element. An imaging method according to the sixth aspect of the present invention is characterized by the following step. That is, there is provided an imaging method of sensing an image of an object with a movable image sensing element and reading a signal generated by the image sensing element, comprising the step of controlling to operate operation of the image sensing element at a predetermined speed without any acceleration during an operation period related to a read of the reading a signal from the image sensing element. An imaging method according to the seventh aspect of the present invention is characterized by the following step. That is, there is provided an imaging method of sensing an image of an object with a movable image sensing element and reading a signal generated by the image sensing element, comprising the step of controlling to operate operation of the image sensing element at a uniform acceleration during an operation period related to a read of the reading a signal from the image sensing element. An imaging method according to the eighth aspect of the present invention is characterized by the following step. That is, there is provided an imaging method of sensing an image of an object with a movable image sensing element and reading a signal generated by the image sensing element, comprising the step of controlling to execute execution of a drive operation related to image acquisition upon determining that a value of a vibration of the image sensing element is not more than a predetermined value during an operation period related to an image read from the image sensing element. A computer-readable storage medium according to the present invention is characterized in that the storage medium stores a processing program for executing the above imaging method. Other objects and advantages besides those discussed above shall be apparent to those skilled in the art for the description of a preferred embodiment of the invention which follows. In the description, reference is made to accompanying drawings, which form a part hereof, and which illustrate an example of the invention. Such example, however, is not exhaustive of the various embodiments of the invention, and therefore reference is made to the claims which follow the description for determining the scope of the invention. The embodiments of the present invention will be described below with reference to the accompanying drawings. (First Embodiment) The present invention is applied to, e.g., a radiation imaging system 100 as shown in FIG. 1. <Arrangement of Radiation Imaging System 100> As shown in FIG. 1, the radiation imaging system 100 has an arrangement in which an imaging device 110 for acquiring an image signal of an object (patient) 102 to be examined, a control device 111 for controlling the entire system 100, a storage device 112 for storing various data such as a control program for control processing by the control device 111 and the image, a display device 113 for displaying the image or the like, an image processing device 114 for executing arbitrary image processing for the image signal of the patient 102, which is obtained by the imaging device 110, an imaging condition instruction device 115 for instructing various imaging conditions in the imaging device 110, an imaging button 116 for instructing the system 100 to start imaging operation, and a radiation generator 117 for generating a radiation (e.g., X-rays) from a radiation tube 101 to the patient 102 are connected to each other through a system bus 120 to exchange data. The imaging device 110 is located at a position where the radiation generated from the radiation tube 101 of the radiation generator 117 can be received through the patient 102, and comprises a chest stand 103, grid 104, phosphor 105, sensor (two-dimensional solid-state image sensing element) 106, signal reading section 107, and grid moving section 108. The chest stand 103, grid 104, phosphor 105, and sensor 106 are arranged in this order from the side of the radiation tube 101 of the radiation generator 117. <Series of Operations of Radiation Imaging System 100> Outlines of the imaging procedure and radiation image generation process in the radiation imaging system 100 will be described here. The user (e.g., radiation technician) positions the patient 102 to the chest stand 103 and selectively inputs appropriate imaging conditions (e.g., tube voltage, tube current, irradiation time, type of sensor 106, and type of radiation tube 101) using the imaging condition instruction device 115. In this embodiment, the imaging conditions are manually input by the user through the imaging condition instruction device 115. However, the present invention is not limited to this. For example, the imaging conditions may be input through a network (not shown) connected to the imaging device 110. Next, the user presses the imaging button 116 to request the control device 111 to start imaging operation. After receiving the imaging operation start request from the user, the control device 111 performs initialization necessary in the system 100 and prompts the radiation generator 117 to irradiate the person with radiation. In accordance with the irradiation instruction from the control device 111, the radiation generator 117 generates radiation from the radiation tube 101. The radiation generated from the radiation tube 101 passes through the patient 102 and reaches chest stand 103. The chest stand 103 is exposed by the radiation transmitted through the patient 102 with a transmitted radiation distribution in accordance with the structure in the patient 102. Since the chest stand 103 is sufficiently transparent to the radiation, the radiation transmitted through the chest stand 103 reaches the grid 104. The grid 104 removes scattering ray components in the radiation transmitted through the chest stand 103 and sends only effective radiation components to the phosphor 105. The phosphor 105 converts the radiation (effective radiation) from the grid 104 into visible light in accordance with the spectral sensitivity of the sensor 106. The sensor 106 receives the radiation from the phosphor 105, converts the radiation light into an electrical signal (image signal) by two-dimensional photoelectric conversion, and accumulates it. The present invention is not limited to this. The sensor 106 may directly convert the radiation from the grid 104 to the electrical signal (image signal). The signal reading section 107 reads the image signal accumulated in the sensor 106 and stores the signal in the storage device 112 as a radiation image signal. The image processing device 114 performs appropriate image processing for the radiation image signal stored in the storage device 112. The display device 113 displays the radiation image signal after processing by the image processing device 114. <Most Characteristic Operation and Arrangement of Radiation Imaging System 100> FIG. 2 is a flow chart showing operation control processing executed by the control device 111 for the system 100. FIGS. 3A to 3F are timing charts showing the operation control timing. The processing shown in FIG. 2 corresponds to processing from the above-described imaging condition input by the user to image signal read from the sensor 106. Step S201 The control device 111 recognizes an irradiation time T exp, the type of sensor 106 used for imaging, and the type of radiation tube 101 on the basis of imaging conditions selectively input by the user through the imaging condition instruction device 115. In accordance with the recognized information, the control device 111 determines control until radiation irradiation and control after radiation irradiation by processing from step S202. Step S202 The control device 111 determines a sensor initialization time Tss in accordance with the type of sensor 106. The sensor initialization time Tss changes depending on the type of sensor 106. For example, when the sensor 106 requires predischarge of a dark current, the pre-read time is the sensor initialization time Tss. From this time, signal accumulation in the sensor 106 starts. Step S203 The control device 111 determines a grid initialization time Tgs and grid vibration convergence time Tge from the irradiation time T exp. More specifically, to reduce stripe image formation on the object by the grid 104, for example, radiation must be transmitted through stripes of 10 or more cycles. However, the moving distance of the grid 104 is limited. Hence, the moving speed of the grid 104 must be optimized in accordance with the irradiation time T exp. In addition, since the grid 104 generally has a focal point, the irradiation central position of radiation and the central position of the grid 104 must be aligned to obtain an image with a satisfactory quality. Hence, a time required until the optimum moving speed (target moving speed) of the grid 104 is obtained and the position of the grid 104 reaches the irradiation central position (target position) of radiation corresponds to the grid initialization time Tgs. In this embodiment, the grid initialization times Tgs until the target moving speed and position of the grid 104 are obtained and the grid vibration convergence times Tge required to converge device vibration caused by movement are obtained as a table by experiments in correspondence with, e.g., various patterns of irradiation time T exp and moving speed of the grid 104 and stored in the storage device 112 in advance. The grid initialization time Tgs and grid vibration convergence time Tge corresponding to the actually obtained irradiation time T exp are determined from the table information in the storage device 112. Step S204 The control device 111 determines a pre-irradiation delay time Txs and post-irradiation delay time Txe on the basis of the type of radiation tube 101. The pre-irradiation delay time Txs is a time after the radiation generator 117 is instructed to permit radiation irradiation until the radiation generator 117 actually starts radiation irradiation, and is determined by the type of radiation generator 117 or radiation tube 101. In this embodiment, the pre-irradiation delay times Txs corresponding to, e.g., various types of radiation generator 117 or radiation tube 101 are prepared as a table in advance, and a corresponding pre-irradiation delay time Txs is determined from the table information. The post-irradiation delay time Txe is a delay time after the elapse of irradiation time T exp until the radiation generator 117 actually ends the radiation irradiation. The post-irradiation delay time Txe is also determined in accordance with the same procedure as that for the pre-irradiation delay time Txs. Step S205 The control device 111 determines an irradiation delay time T1. The irradiation delay time T1 is a delay time after an imaging request is input by the user through the imaging button 116 until the radiation generator 117 actually starts radiation irradiation. Of the sensor initialization time Tss determined in step S202, the grid initialization time Tgs determined in step S203, and the pre-irradiation delay time Txs determined in step S204, the longest time is determined as the irradiation delay time T1. Step S206 The control device 111 determines a time table before irradiation. This time table is determined from the sensor initialization time Tss determined in step S202, the grid initialization time Tgs determined in step S203, and the pre-irradiation delay time Txs determined in step S204. More specifically, the control sequence and times (timings) of initialization of the sensor 106, start of drive of the grid 104, and radiation irradiation instruction (irradiation permission) to the radiation generator 117 after the imaging request input by the user through the imaging button 116 is recognized are determined by subtracting each delay time from the irradiation delay time T1 determined in step S205. The initialization timing of the sensor 106 is determined as “T1−Tss”. The drive start timing of the grid 104 is determined as “T1−Tgs”. The radiation irradiation instruction (irradiation permission) timing for the radiation generator 117 is determined as “T1−Txs”. Step S207 After control before radiation irradiation is control parameters are determined in the above-described way, the control device 111 determines whether an imaging request is input by the user through the imaging button 116 and stands by until an imaging request is received. Step S208 Upon recognizing that an imaging request is input by the user through the imaging button 116, the control device 111 executes operation control according to the time table determined in step S206. Initialization of the sensor 106 is started after the elapse of “T1−Tss”, drive of the grid 104 is started after the elapse of “T1−Tgs”, and irradiation permission is executed after the elapse of “T1−Txs”. Step S209 The control device 111 stands by until the total time (T1+T exp+Txe) of the irradiation time (actual exposure time) T exp determined in step S201, the post-irradiation delay time Txe determined in step S204, and the irradiation delay time T1 determined in step S205 elapses. Step S210 When recognizing that the time (T1+T exp+Txe) has elapsed, the control device 111 stops driving the grid 104 through the grid moving section 108. Step S211 The control device 111 stands by until the grid vibration convergence time Tge determined in step S203 elapses. Step S212 When recognizing that the grid vibration convergence time Tge has elapsed, the control device 111 causes the signal reading section 107 to start reading the signal accumulated in the sensor 106. In the operation control for the radiation imaging system 100 shown in the flow chart of FIG. 2, especially, since the operation stands by for the post-irradiation delay time Txe after the elapse of irradiation time T exp, stripe image formation on the object by the grid 104 can be prevented. In addition, since drive the driving of the grid 104 is stopped, the influence of electromagnetic noise generated from the grid moving section 108 can be prevented. Furthermore, since the operation stands by for the grid vibration convergence time Tge after the stop of drive stopping the driving of the grid 104, the influence of device vibration can be prevented. Hence, after the imaging request from the user is recognized, the control device 111 controls the operation of the system 100 in accordance with the flow chart in FIG. 2, thereby acquiring a satisfactory image. The above operation control for the radiation imaging system 100 will be described below in more detail with reference to the timing charts shown in FIGS. 3A to 3F. The timing charts of FIGS. 3A to 3F explain timings after the imaging button 116 is pressed. In accordance with the imaging conditions input by the user, for example, Irradiation time T exp=100 ms Sensor initialization time Tss=200 ms Grid initialization time Tgs=300 ms Pre-irradiation delay time Txs=100 ms Grid vibration convergence time Tge=300 ms Post-irradiation delay time Txe=100 ms are determined. In this case, the irradiation delay time T1 as the longest time of the sensor initialization time Tss, grid initialization time Tgs, and pre-irradiation delay time Txs is determined byT1=max(tss, Tgs, Txs)=Tgs=300 ms Operation control until radiation irradiation is determined from these initial conditions. Next, control timings for sensor initialization, start of grid movement, and irradiation permission instruction after recognition of the imaging request are determined by subtracting a corresponding time required for operation from the irradiation delay time T1.Sensor initialization timing: T1−Tss=100 msGrid movement start timing: T1−Tgs=0 msIrradiation enable signal transmission timing: T1−Txs=200 ms Control timings after radiation irradiation are so determined that movement control for the grid 104 is stopped after the elapse of actual irradiation time obtained by adding the irradiation time T exp and post-irradiation delay time Txe to the irradiation delay T1, and the signal read from the sensor 106 is started after the elapse of grid vibration convergence time Tge. That is, the grid control stop timing and signal read start timing are determined byGrid control stop timing: T1+T exp+Txe=500 msSignal read start timing: T1+T exp+Txe+Tge=800 ms After the control timings are determined, an imaging request (FIG. 3A) input by the user by pressing the imaging button 116 is waited upon. When an imaging request is recognized, operation control for the radiation imaging system 100 is started on the basis of the determined control timings. First, movement (motion) of the grid 104 is started, as shown in FIG. 3B. The moving speed of the grid 104 acceleratingly increases and reaches an irradiation enable state after the elapse of 300 ms (grid initialization time Tgs=300 ms), as shown in FIG. 3C. Next, as shown in FIG. 3F, after the elapse of 100 ms (sensor initialization timing: T1−Tss=100 ms) from imaging request recognition, initialization of the sensor 106 is started. After the elapse of 200 ms (sensor initialization time Tss=200 ms), initialization of the sensor 106 is ended. As shown in FIG. 3D, after the elapse of 200 ms (irradiation enable signal transmission timing: T1−Txs=200 ms) from imaging request recognition, the radiation generator 117 is instructed to start irradiation. The radiation generator 117 starts actual irradiation after the elapse of 100 ms (pre-irradiation delay time Txs=100 ms), as shown in FIG. 3E. After the elapse of 500 ms (grid control stop timing: T1+T exp+Txe=500 ms) from imaging request recognition, actual irradiation by the radiation generator 117 is ended. At this time, movement control for the grid 104 is stopped, as shown in FIG. 3B, and the moving speed of the grid 104 gradually decreases. Along with this deceleration, the vibration of the imaging device 110, that is generated by moving the grid 104, starts converging. After that, as shown in FIG. 3F, after the elapse of 800 ms (signal read start timing: T1+T exp+Txe+Tge=800 ms) from imaging request recognition, the signal reading section 107 is instructed to end signal accumulation in the sensor 106 and start reading the signal. At this time, the vibration of the imaging device 110 has become so small that it does not affect the image quality. As a result, a satisfactory image can be obtained. (Second Embodiment) The present invention is applied to, e.g., a radiation imaging system 300 as shown in FIG. 4. This radiation imaging system 300 has the same arrangement as that of the radiation imaging system 100 shown in FIG. 1 except that a radiation detector 302 for detecting a radiation irradiation state and an a vibration measurement device 301 for measuring the vibration state of a grid 104 are prepared in an imaging device 110. The same reference numerals as in the radiation imaging system 100 shown in FIG. 1 denote the same parts in the radiation imaging system 300 shown in FIG. 4, and a detailed description thereof will be omitted. Only parts different from the radiation imaging system 100 in FIG. 1 will be described in detail. FIG. 5 is a flow chart showing operation control processing executed by a control device 111 of this embodiment for the system 300. FIGS. 6A to 6H are timing charts showing the operation control timing. The same step numbers as in the flow chart of FIG. 2 denote the same processing steps in the flow chart of FIG. 5, and a detailed description thereof will be omitted. Step S201 The control device 111 recognizes an irradiation time T exp, the type of sensor 106 used for imaging, and the type of radiation tube 101 on the basis of imaging conditions selectively input by the user through an imaging condition instruction device 115. In accordance with the recognized information, the control device 111 determines control until radiation irradiation and control after radiation irradiation by processing from step S202. Step S202 The control device 111 determines a sensor initialization time Tss in accordance with the type of sensor 106. Step S203′ The control device 111 determines a grid initialization time Tgs (time until the grid 104 reaches the target moving speed and position) from the irradiation time T exp. Step S204′ The control device 111 determines a pre-irradiation delay time Txs (time after radiation irradiation permission is instructed to a radiation generator 117 until the radiation generator 117 actually starts radiation irradiation) on the basis of the type of radiation tube 101. Step S205 The control device 111 determines an irradiation delay time T1 (the longest time of the sensor initialization time Tss, grid initialization time Tgs, and pre-irradiation delay time Txs). Step S206 The control device 111 determines, as a time table before irradiation, the initialization timing of the sensor 106 as “T1−Tss”, the drive start timing of the grid 104 as “T1−Tgs”, and the radiation irradiation instruction (irradiation permission) timing for the radiation generator 117 as “T1−Txs”. Step S207 After control before radiation irradiation is control parameters are determined in the above-described way, the control device 111 determines whether an imaging request is input by the user through an imaging button 116 and stands by until an imaging request is received. Step S208 Upon recognizing that an imaging request is input by the user through the imaging button 116, the control device 111 executes operation control according to the time table determined in step S206. Initialization of the sensor 106 is started after the elapse of “T1−Tss”, drive the driving of the grid 104 is started after the elapse of “T1−Tgs”, and irradiation permission is executed after the elapse of “T1−Txs”. Step S209′ The control device 111 determines on the basis of a detection signal output from the radiation detector 302 whether radiation irradiation by the radiation generator 117 is ended. Step S210 Upon recognizing that radiation irradiation by the radiation generator 117 is ended, the control device 111 stops driving the grid 104 through a grid moving section 108. Step S211′ The control device 111 determines on the basis of a measurement result from the vibration measurement device 301 whether the vibration of the grid 104 has converged. Step S212 When recognizing that the vibration of the grid 104 has converged, the control device 111 causes a signal reading section 107 to start reading the signal accumulated in the sensor 106. In the operation control for the radiation imaging system 300 shown in the flow chart of FIG. 5, especially when the end of radiation irradiation is recognized in accordance with the detection result from the radiation detector 302, drive the driving of the grid 104 is stopped. For this reason, the influence of electromagnetic noise generated from the grid moving section 108 can be prevented. Furthermore, since the operation stands until it is determined on the basis of the measurement result from the vibration measurement device 301 that the vibration of the grid 104 has converged after the stop of drive stopping the driving of the grid 104, the influence of device vibration can be prevented. Hence, after the imaging request from the user is recognized, the control device 111 controls the operation of the system 300 in accordance with the flow chart in FIG. 5, thereby acquiring a satisfactory image. The above operation control for the radiation imaging system 300 will be described below in more detail with reference to the timing charts shown in FIGS. 6A to 6H. The timing charts of FIGS. 6A to 6H explain timings after the imaging button 116 is pressed. In accordance with the imaging conditions input by the user, for example, Irradiation time T exp=100 ms Sensor initialization time Tss=200 ms Grid initialization time Tgs=300 ms Pre-irradiation delay time Txs=100 ms are determined. In this case, the irradiation delay time T1 as the longest time of the sensor initialization time Tss, grid initialization time Tgs, and pre-irradiation delay time Txs is determined byT1=max(Tss, Tgs, Txs)=Tgs=300 ms Operation control until radiation irradiation is determined from these initial conditions. Next, control timings for sensor initialization, start of grid movement, and irradiation permission instruction after recognition of the imaging request are determined by subtracting a corresponding time required for operation from the irradiation delay time T1.Sensor initialisation timing: T1−Tss=100 msGrid movement start timing: T1−Tgs=0 msIrradiation enable signal transmission timing: T1−Txs=200 ms After the control timings are determined, an imaging request (FIG. 6A) input by the user by pressing the imaging button 116 is waited upon. When an imaging request is recognized, operation control for the radiation imaging system 300 is started on the basis of the determined control timings. First, movement (motion) of the grid 104 is started, as shown in FIG. 6B. Simultaneously, the vibration detection signal representing that the grid 104 is in a moving state is set at High level, as shown in FIG. 6G. The moving speed of the grid 104 acceleratingly increases and reaches an irradiation enable state after the elapse of 300 ms (grid initialization time Tgs=300 ms), as shown in FIG. 6C. Next, as shown in FIG. 6H, after the elapse of 100 ms (sensor initialization timing: T1−Tss=100 ms) from imaging request recognition, initialization of the sensor 106 is started. After the elapse of 200 ms (sensor initialization time Tss=200 ms), initialization of the sensor 106 is ended. As shown in FIG. 6D, after the elapse of 200 ms (irradiation enable signal transmission timing: T1−Txs=200 ms) from imaging request recognition, the radiation generator 117 is instructed to start irradiation. The radiation generator 117 starts actual irradiation after the elapse of 100 ms (pre-irradiation delay time Txs=100 ms), as shown in FIG. 6E. Simultaneously, the radiation detection signal representing radiation irradiation is set at High level, as shown in FIG. 6F. When radiation irradiation is ended, and the output from the radiation detector 302 becomes smaller than a predetermined threshold value, it is determined that irradiation is ended. As shown in FIG. 6F, the radiation detection signal is set at Low level. Along with this processing, movement control for the grid 104 is stopped, as shown in FIG. 6B. The moving speed of the grid 104 gradually decreases. The vibration state of the grid 104 at this time is observed by the vibration measurement device 301. When the vibration of the imaging device 110, that is generated by moving the grid 104, starts converging, and it is recognized that the output from the vibration measurement device 301 becomes smaller than a predetermined vibration amount, the vibration detection signal is set at Low level, as shown in FIG. 6G. As shown in FIG. 6F, the signal reading section 107 is instructed to end signal accumulation in the sensor 106 and start reading the signal. At this time, the vibration of the imaging device 110 has become so small that it does not affect the image quality. As a result, a satisfactory image can be obtained. The object of the present invention is achieved even by supplying a storage medium which stores software program codes for implementing the functions of the host and terminal in accordance with the first and second embodiments to in a system or apparatus and causing the computer (or a CPU or MPU) of the system or apparatus to read and execute the program codes stored in the storage medium. In this case, the program codes read from the storage medium implement the functions of the first and second embodiments by themselves, and the storage medium which stores the program codes constitutes the present invention. As a storage medium for supplying the program codes, for example, a ROM, a floppy disk, hard disk, optical disk, magnetooptical disk, CD-ROM, CD-R, magnetic tape, non-volatile memory card or the like can be used. The functions of the first and second embodiments are implemented not only when the readout program codes are executed by the computer but also when the operating system (OS) running on the computer performs part or all of actual processing on the basis of the instructions of the program codes. The functions of the first and second embodiments are also implemented when the program codes read from the storage medium are written in the memory of a function expansion board inserted into the computer or a function expansion unit connected to the computer, and the CPU of the function expansion board or function expansion unit performs part or all of actual processing on the basis of the instructions of the program codes. As described above, according to the above embodiments, since the grid is stopped before the read of reading of the signal accumulated in the image sensing element is started, the influence of electromagnetic noise due to grid movement can be eliminated. Hence, no noise is superposed on the image (radiation image or the like) obtained from the read signal from the image sensing element, and high-quality image can be obtained. When a predetermined standby time is set from the stop of the grid, the signal read from the image sensing element starts after the influence of vibration of the imaging element due to grid movement is reduced. For this reason, an image with a higher quality can be obtained. Hence, the quality of the image can be prevented from degrading due to the influence of electromagnetic noise upon grid movement. In addition, the quality of the image can be prevented from degrading due to the influence of vibration of the image sensing element upon grid movement. For example, when the above embodiments are applied to radiation imaging, a satisfactory radiation image free from noise can be provided. For this reason, a diagnostic error in image diagnosis can be reliably prevented. (Third Embodiment) FIG. 7 is a block diagram showing the arrangement of an X-ray image sensing system according to the third embodiment of the present invention. Reference numeral 10 denotes an X-ray room; 12, an X-ray control room; and 14, a diagnosis room. The X-ray control room 12 has a system controller 20 for controlling the entire operation of the X-ray image sensing system. An operator interface 22 having an X-ray exposure request switch, touch panel, mouse, keyboard, joystick, foot switch, and the like is used by an operator 21 to input various instructions to the system controller 20. The contents of instructions by the operator 21 are, e.g., imaging conditions (still/moving image, X-ray tube voltage, tube current, and X-ray irradiation time), imaging timing, image processing conditions, ID of a patient, and processing method for a read image. An image sensing controller 24 controls the X-ray image sensing system placed in the X-ray room 10. An image processor 26 processes an image obtained by the X-ray image sensing system in the X-ray room 10. Image processing by the image processor 26 includes, e.g., image data correction, space filtering, recursive processing, grayscale processing, scattered ray correction, and dynamic range (DR) compression processing. A large-capacity high-speed storage device 28 stores basic image data processed by the image processor 26 and is formed from, e.g., a hard disk array such as a RAID. A monitor display (to be referred to as a monitor hereinafter) 30 displays an image. A display controller 32 controls the monitor 30 to make it display various characters and images. Reference numeral 34 denotes a large-capacity external storage device (e.g., a magnetooptical disk). A LAN board 36 connects the X-ray control room 12 to the diagnosis room 14 to transfer, e.g., an image obtained in the X-ray room 10 to the apparatus in the diagnosis room 14. An X-ray generator 40 for generating X-rays is placed in the X-ray room 10. The X-ray generator 40 comprises an X-ray tube 42 for generating X-rays, a high-voltage source 44 controlled by the image sensing controller 24 to drive the X-ray tube 42, and an X-ray stop 46 for converging an X-ray beam generated by the X-ray tube 42 to a desired image sensing region. A patient 50 as an object to be examined lies on an imaging bed 48. The imaging bed 48 is driven in accordance with a control signal from the image sensing controller 24 so that the direction of the patient 50 with respect to the X-ray beam from the X-ray generator 40 can be changed. An X-ray detector 52 for detecting the X-ray beam transmitted through the patient 50 and the imaging bed 48 is placed under the imaging bed 48. The X-ray detector 52 comprises a stack of a grid 54, scintillator 56, photodetector array 58, and X-ray exposure amount monitor 60, and a driver 62 for driving the photodetector array 58. The grid 54 is arranged to reduce the influence of X-ray scattering caused when the X-rays are transmitted through the patient 50. The grid 54 is formed from an X-ray non-absorbing member and X-ray absorbing member and has a stripe structure of, e.g., Al and Pb. In X-ray irradiation, to prevent moire by the matrix ratio relationship between the photodetector array 58 and the grid 54, the X-ray detector 52 vibrates the grid 54 in accordance with a control signal from the driver 62 on the basis of settings from the image sensing controller 24. In the scintillator 56, the matrix substance of phosphor is excited (absorbed) by high-energy X-rays, and fluorescent light in the visible region is generated by the recombination energy. That is, the X-rays are converted into visible light. The fluorescent light is generated by the matrix itself such as CaWo4 or CdWo4 or luminescence center substance such as CsI:Tl or ZnS:Ag doped into the matrix. The photodetector array 58 converts the visible light obtained by the scintillator 56 into an electrical signal. The X-ray exposure amount monitor 60 is arranged in order to monitor the X-ray transmission amount. The X-ray exposure amount monitor 60 may directly detect X-rays using a silicon crystal light-receiving element or the like, or detect fluorescent light generated by the scintillator 56. In this embodiment, the X-ray exposure amount monitor 60 is formed from an amorphous silicon light-receiving element formed on the lower surface of the substrate of the photodetector array 58, detects visible light (proportional to the X-ray dose) transmitted through the photodetector array 58, and transmits the light amount information to the image sensing controller 24. The image sensing controller 24 controls the X-ray generator 40 on the basis of the information from the X-ray exposure amount monitor 60 to adjust the X-ray dose. The driver 62 drives the photodetector array 58 under the control of the image sensing controller 24 to read a signal from each pixel. Operations of the photodetector array 58 and driver 62 will be described later in detail. In the diagnosis room 14, an image processing terminal 70 for processing an image from the LAN board 36 or assisting the diagnosis, a video display monitor 72 for outputting an image (moving image/still image) from the LAN board 36, an image printer 74, and a file server 76 for storing image data are prepared. A control signal from the system controller 20 to each device can be generated by an instruction from the operator interface 22 in the X-ray control room 12 or the image processing terminal 70 in the diagnosis room 14. Basic operation of the system controller 20 will be described next. On the basis of an instruction from the operator 21, the system controller 20 outputs an imaging condition instruction to the image sensing controller 24 for controlling the sequence of the X-ray image sensing system. On the basis of the instruction, the image sensing controller 24 drives the X-ray generator 40, imaging bed 48, and X-ray detector 52 to obtain an X-ray image. The X-ray image signal output from the X-ray. detector 52 is supplied to the image processor 26, subjected to image processing designated by the operator 21, displayed on the monitor 30 as an image, and simultaneously, stored in the storage device 28 as basic image data. The system controller 20 also executes image re-processing and display of its result, image data transfer to a device on the network, storage, video display, and film printing on the basis of instructions from the operator 21. Basic operation of the system shown in FIG. 7 will be described in accordance with the signal flow. The high-voltage source 44 of the X-ray generator 40 applies a high voltage for generating X-rays to the X-ray tube 42 in accordance with a control signal from the X-ray tube 42. The X-ray tube 42 generates an X-ray beam. The patient 50 as an object to be examined is irradiated with the generated X-ray beam through the X-ray stop 46. The X-ray stop 46 is controlled by the image sensing controller 24 in accordance with the position where the object is to be irradiated with the X-ray beam. That is, the X-ray stop 46 shapes the X-ray beam as the image sensing region changes so as not to perform unnecessary X-ray irradiation. The X-ray beam output from the X-ray generator 40 passes through the patient 50 who lies on the imaging bed 48 transparent to X-rays, and the imaging bed 48 and enters the X-ray detector 52. The imaging bed 48 is controlled by the image sensing controller 24 such that the X-ray beam passes through the object to be examined at different portions or in different directions. The grid 54 of the X-ray detector 52 reduces the influence of X-ray scattering caused by passing the X-ray beam through the patient 50. To prevent moire by the matrix ratio relationship between the photodetector array 58 and the grid 54, the image sensing controller 24 vibrates the grid 54 in X-ray irradiation. In the scintillator 56, the matrix substance of phosphor is excited (absorbs the X-rays) by the high-energy X-rays, and fluorescent light in the visible region is generated by the recombination energy generated at that time. The photodetector array 58 arranged adjacent to the scintillator 56 converts the fluorescent light generated by the scintillator 56 into an electrical signal. That is, the scintillator 56 converts the X-ray image into a visible light image, and the photodetector array 58 converts the visible light image into an electrical signal. The X-ray exposure amount monitor 60 detects the visible light (proportional to the X-ray dose) transmitted through the photodetector array 58 and supplies the detection amount information to the image sensing controller 24. The image sensing controller 24 controls the high-voltage source 44 on the basis of the X-ray exposure amount information to cut off or adjust the X-rays. The driver 62 drives the photodetector array 58 under the control of the image sensing controller 24 to read a pixel signal from each photodetector. Details of the photodetector array 58 and driver 62 will be described later. The pixel signal output from the X-ray detector 52 is supplied to the image processor 26 in the X-ray control room 12. Since large noise is generated by X-ray generation in the X-ray room 10, the signal transmission path from the X-ray detector 52 to the image processor 26 must be highly resistant to noise. More specifically, a digital transmission system having an advanced error correction function or a shielded twisted pair line or optical fiber by a differential driver is preferably used. Although details will be described later, the image processor 26 switches the image signal display format on the basis of an instruction from the system controller 20, executes image signal correction, space filtering, and recursive processing in real time, and also can execute grayscale processing, scattered ray correction, and DR compression processing. The image processed by the image processor 26 is displayed on the screen of the monitor 30. Simultaneously with real-time image processing, image information (basic image) that has undergone only image correction is stored in the storage device 28. The image information stored in the storage device 28 is reconstructed to satisfy a predetermined standard (e.g., Image Save & Carry (IS&C)) and stored in the external storage device 34 and a hard disk in the file server 76 on the basis of an instruction from the operator 21. The devices in the X-ray control room 12 are connected to a LAN (or WAN) through the LAN board 36. A plurality of X-ray image sensing systems can be connected to the LAN. The LAN board 36 outputs image data in accordance with a predetermined protocol (e.g., Digital Imaging and Communications in Medicine (DICOM)). By displaying the X-ray image on the screen of the monitor 72 connected to the LAN as a high-resolution still image or moving image, real-time remote diagnosis by a doctor is possible almost simultaneously with X-ray imaging. FIG. 8 is a circuit diagram showing an equivalent circuit of a construction unit of the photodetector array 58. One element is formed from a photodetection section 80 and a switching thin film transistor (TFT) 82 for controlling charge accumulation and read reading and is generally formed from amorphous silicon (a-Si) on a glass substrate. The photodetection section 80 is formed from a parallel circuit of a photodiode 80a and capacitor 80b, and a capacitor 80c connected in series with the capacitor 80b. Charges by the photoelectric conversion effect are described as a constant current source 81. The capacitor 80b may be either the parasitic capacitance of the photodiode 80a or an additional capacitor for improving the dynamic range of the photodiode 80a. The common bias electrode (to be referred to as a D electrode hereinafter) of the photodetection section 80 is connected to a bias power supply 84 through a bias line Lb. An electrode (to be referred to as a G electrode hereinafter) on the side of the switching TFT 82 of the photodetection section 80 is connected to a capacitor 86 and charge reading preamplifier 88 through the switching TFT 82. The input to the preamplifier 88 is also connected to ground through a reset switch 90 and signal line bias power supply 91. Device operation of the photodetection section 80 will be described with reference to FIGS. 9A to 9C. FIGS. 9A and 9B are views showing the energy band of a photoelectric conversion element that exhibits the refresh and photoelectric conversion mode operations of this embodiment. FIGS. 9A and 9B show states in the direction of thickness of each layer. A lower electrode (G electrode) 301 is formed from Cr. An insulating layer 302 is formed from SiN and inhibits both electrons and holes from passing. The thickness of the insulating layer 302 is set to be 50 nm or more such that electrons and holes cannot move by the tunnel effect. A photoelectric conversion semiconductor layer 303 is formed from an intrinsic semiconductor layer of hydrogenated amorphous silicon a-Si. An injection inhibiting 304 is formed from an n-type a-Si layer for inhibiting holes from being injected into the photoelectric conversion semiconductor layer 303. An upper electrode (D layer) 305 is formed from Al. In this embodiment, the D electrode does not completely cover the n-layer. However, since electrons freely move between the D electrode and the n-layer, the D electrode and n-layer always have an equipotential state. The following description will be made assuming this. This photoelectric conversion element performs two types of operation: refresh mode and photoelectric conversion mode in accordance with the manner the voltage is applied to the D and G electrodes. Referring to FIG. 9A, a potential negative with respect to the G electrode is applied to the D electrode. Holes represented by solid dots in the mode shown in FIG. 9B is held for a certain period, the state returns to the refresh mode shown in FIG. 9A again. The holes that are staying in the i-layer 303 are moved to the D electrode, as described above, and simultaneously, a current corresponding to the holes flows. The number of holes corresponds to the total amount of light incident during the photoelectric conversion mode period. At this time, a current corresponding to the number of electrons injected into the i-layer 303 also flows. The number of electrons is almost constant and is detected by subtraction. That is, the photoelectric conversion element of this embodiment can output the amount of light incident in real time and simultaneously output the total amount of light incident for a given period. However, when the period of the photoelectric conversion mode becomes long due to some reason, or the illuminance of incident light is high, no current may flow although light is incident. This is because a number of holes stay in the i-layer 303 and are recombined with holes in the i-layer 303, as shown in FIG. 9C. If the light incident state changes in this state, a current may unstably flow. When the mode is returned to the refresh mode, the holes in the i-layer 303 are swept, and a current proportional to light flows again in the next photoelectric conversion mode. In the above description, in sweeping holes in i-layer 303 are moved to the D electrode by the electric field. Simultaneously, electrons represented by hollow dots are injected into the i-layer 303. At this time, some holes and electrons are recombined in the n-layer 304 and i-layer 303 and disappear. When this state continues for a sufficiently long time, the holes in the i-layer 303 are swept from the i-layer 303. To change this state to the photoelectric conversion mode shown in FIG. 9B, a potential positive with respect to the G electrode is applied to the D electrode. Electrons in the i-layer 303 are instantaneously moved to the D electrode. However, holes are not moved to the i-layer 303 because the n-layer 304 acts as an injection inhibiting layer. When light becomes incident on the i-layer 303 in this state, the light is absorbed to generate electron-hole pairs. The electrons are moved to the D electrode by the electric field, and the holes move through the i-layer 303 and reach the interface between the i-layer 303 and the insulating layer 302. However, since the holes cannot enter the insulating layer 302 and move to the interface to the insulating layer 302 in the i-layer 303, a current flows from the G electrode to maintain the electrical neutrality. This current corresponds to the electron-hole pairs generated by the light and is therefore proportional to the incident light. After the state in the photoelectric conversion the i-layer 303 in the refresh mode, it is ideal to sweep all holes. However, even when some holes are extracted, an effect can be obtained, and a current equal to that described above can be obtained without any problem. That is, it is only necessary to prevent the state shown in FIG. 9C in the detection opportunity in the next photoelectric conversion mode, and it suffices to determine the potential of the D electrode with respect to the G electrode in the refresh mode, the period of the refresh mode, and the characteristics of the n-layer 304 as an injection inhibiting layer. Electron injection into the i-layer 303 in the refresh mode is not a necessary condition. The potential of the D electrode with respect to the G electrode is nor limited to a negative potential. When a number of holes stay in the i-layer 303, the electric field in the i-layer 303 is applied in a direction to move the holes to the D electrode even when the potential of the D electrode is higher than that of the G electrode. For the characteristics of the n-layer 304 as an injection inhibiting layer as well, the capability of injecting electrons into the i-layer 303 is not a necessary condition. Referring back to FIG. 8, the signal read from one pixel will be described. First, the switching TFT 82 and reset switch 90 are temporarily turned on to set the bias power supply 84 at a potential in the refresh mode. After the capacitors 80b and 80c are reset, the bias power supply 84 is set at a potential in the photoelectric conversion mode, and the switching TFT 82 and reset switch 90 are sequentially turned off. After that, X-rays are generated to irradiate the patient 50. The scintillator 56 converts the X-ray image transmitted through the patient 50 into a visible light image. The photodiode 80a is turned on by the visible light image to discharge the capacitor 80b. The switching TFT 82 is turned on to connect the capacitors 80b and 86. Information in the capacitor 80c is also transmitted to the capacitor 86. The voltage by charges accumulated in the capacitor 86 is amplified by the preamplifier 88, or the charges are converted into a voltage by a capacitor 89 indicated by the dotted line, and the voltage is externally output. FIG. 10 is a circuit diagram showing another equivalent circuit of a construction unit of the photodetector array 58. One element is formed from the photodetection section 80 and switching thin film transistor (TFT) 82 for controlling charge accumulation and read reading and is generally formed from amorphous silicon (a-Si) on a glass substrate. The photodetection section 80 is formed from the parallel circuit of the photodiode 80a and capacitor 80b. Charges by the photoelectric conversion effect are described as the constant current source 81. The capacitor 80b may be either the parasitic capacitance of the photodiode 80a or an additional capacitor for improving the dynamic range of the photodiode 80a. The cathode of the photodetection section 80 (photodiode 80a) is connected to a bias power supply 85 through the bias line Lb as a common electrode (D electrode). The anode of the photodetection section 80 (photodiode 80a) is connected from the gate electrode (G electrode) to the capacitor 86 and charge reading preamplifier 88 through the switching TFT 82. The input to the preamplifier 88 is also connected to ground through the reset switch 90 and signal line bias power supply 91. First, the switching TFT 82 and reset switch 90 are temporarily turned on to reset the capacitor 80b. Then, the switching TFT 82 and reset switch 90 are turned off. After that, X-rays are generated to irradiate the patient 50. The scintillator 56 converts the X-ray image transmitted through the patient 50 into a visible light image. The photodiode 80a is turned on by the visible light image to discharge the capacitor 80b. The switching TFT 82 is turned on to connect the capacitors 80b and 86. Information of the discharge amount of the capacitor 80b is also transmitted to the capacitor 86. The voltage by charges accumulated in the capacitor 86 is amplified by the preamplifier 88, or the charges are converted into a voltage by the capacitor 89 indicated by the dotted line, and the voltage is externally output. Photoelectric conversion operation when the photoelectric conversion element shown in FIG. 9 or 10 is expanded to a two-dimensional array will be described next. FIG. 11 is a schematic view showing the equivalent circuit of the photodetector array 58 having photoelectric conversion elements arranged in a two-dimensional array. Two-dimensional read operation is the same as in the above two types of equivalent circuits, and FIG. 11 shows an arrangement using the equivalent circuit shown in FIG. 10. The photodetector array 58 is formed from about 2,000×2,000 to 4,000×4,000 pixels, and the array area is about 200 mm×200 mm to 500 mm×500 mm. Referring to FIG. 11, the photodetector array 58 is formed from 4,096×4,096 pixels, and the array area is 430 mm×430 mm. Hence, the size of one pixel is about 105 μm×105 μm. In this case, 4,096 pixels arranged in the horizontal direction form one block, and 4,096 blocks are arranged in the vertical direction to obtain a two-dimensional structure. Referring to FIG. 11, the photodetector array having 4,096×4,096 pixels is formed from one substrate. However, four photodetector arrays each having 2,048×2,048 pixels may be combined. In this case, although combining the four photodetector arrays is time-consuming, the yield of each photodetector array improves, and the total yield also improves. As described with reference to FIGS. 8 and 10, one pixel is formed from one photodetection section 80 and switching TFT 82. Each of photoelectric conversion elements PD (1,1) to (4096,4096) corresponds to the photodetection section 80, and each of transfer switches SW (1,1) to (4096,4096) corresponds to the switching TFT 82. The gate electrode (G electrode) of a photoelectric conversion element PD (m,n) is connected to a common column signal line Lcm for that column through a corresponding switch SW (m,n). For example, the photoelectric conversion elements PD (1,1) to (4096,1) of the first column are connected to a first column signal line Lc1. All the common electrodes (D electrodes) of the photoelectric conversion elements PD (m,n) are connected to the bias power supply 85 through the bias line Lb. Control terminals of the switches SW (m,n) of the same row are connected to a common row selection line Lrn. For example, the switches SW (1,1) to (1,4096) of the first row are connected to a row selection line Lr1. the The row selection lines Lr1 to Lr4096 are connected to the image sensing controller 24 through a line selector 92. The line selector 92 is constituted by an address decoder 94 which decodes a control signal from the image sensing controller 24 and determines a specific photoelectric conversion element from which the signal charges are to be read, and 4,096 switch elements 96 turned on/off in accordance with the output from the address decoder 94. With this arrangement, signal charges can be read from the photoelectric conversion element PD (m,n) connected to the switch SW (m,n) connected to the arbitrary line Lrn. As the simplest structure of the line selector 92, it may be constructed by a shift register used in, e.g., a liquid crystal display. The column signal lines Lc1 to Lc4096 are connected to a signal read circuit 100 controlled by the image sensing controller 24. In the signal read circuit 100, reset switches 102-1 to 102-4096 reset the column signal lines Lc1 to Lc4096 to a reset reference potential 101. Preamplifiers 106-1 to 106-4096 amplify signal potentials from the column signal lines Lc1 to Lc4096. Sample-and-hold (S/H) circuits 108-1 to 108-4096 sample and hold the outputs from the preamplifiers 106-1 to 106-4096. An analog multiplexer 110 multiplexes the outputs from the sample-and-hold circuits 108-1 to 108-4096 on the time axis. An A/D converter 112 converts the analog output from the multiplexer 110 into a digital signal. The output from the A/D converter 112 is supplied to the image processor 26. In the photodetector array shown in FIG. 11, 4,096×4,096 pixels are divided into 4,096 columns by the column signal lines Lc1 to Lc4096, and signal charges are simultaneously read from 4,096 pixels per row, transferred to the analog multiplexer 110 through the column signal lines Lc1 to Lc4096, preamplifiers 106-1 to 106-4096, and S/H circuits 108-1 to 108-4096, multiplexed on the time axis, and sequentially converted into a digital signal by the A/D converter 112. Referring to FIG. 9, the signal read circuit 100 has only one A/D converter 112. Actually, A/D conversion is simultaneously executed by four to 32 systems. This is because the image signal read time must be shortened without unnecessarily increasing the analog signal band and A/D conversion rate. The signal charge accumulation time and A/D conversion time have a close relationship. When high-speed A/D conversion is performed, the band of the analog circuit widens, and a desired S/N ratio can hardly be attained. Normally, the image signal read time need be shortened without unnecessarily increasing the A/D conversion speed. To do this, a number of A/D converters are used to A/D-convert the output from the multiplexer 110. However, the larger the number of A/D converters is, the higher the cost becomes. Considering the above points, an appropriate number of A/D converters are used. Since the X-ray irradiation time is about 10 to 500 msec, the full screen read time or charge accumulation time is appropriately set on the order of 100 msec or relatively short. For example, to sequentially drive all pixels to read an image, the analog signal band is set to about 50 MHz, and A/D conversion is performed at a sampling rate of, e.g., 10 MHz. In this case, at least four A/D converters are required. In this embodiment, A/D conversion is simultaneously performed by 16 systems. The outputs from the 16 A/D converters are input to 16 corresponding memories (e.g., FIFO) (not shown). By selectively switching the memories, image data corresponding to one continuous scanning line is transferred to the image processor 26. FIG. 12 is a schematic timing chart of the sensor read. Two-dimensional drive in sensing a still image by X-ray irradiation of one cycle will be described with reference to FIGS. 11 and 12. Reference numeral 601 schematically denotes an X-ray exposure request control signal; 602, an X-ray exposure state; 603, a current in the current source 81 in the sensor; 604, a control state of the row selection line Lrn; and 605, an analog input to the A/D converter 112. In the equivalent circuit sensor shown in FIG. 8, first, the driver 62 sets the bias line to a bias value Vr in the refresh mode, connects all the column signal lines Lc1 to Lc4096 to the reset reference potential 101 to initialize them to a predetermined bias value of the column signal lines Lc, and applies a positive voltage Vgh to all the row selection lines Lr1 to Lr4096. The switches (1,1) to (4096,4096) are turned on to refresh the G electrodes of all the photoelectric conversion elements to Vbt and the D electrodes to Vr. After that, the driver 62 sets the bias line Lb to a bias value Vs in the photoelectric conversion mode, release all the column signal lines Lc1 to Lc4096 from the reset reference potential 101, and applies a voltage Vg1 to all the row selection lines Lr1 to Lr4096 to turn off the switches (1,1) to (4096,4096). The mode shifts to the photoelectric conversion mode. Operation from here is common to the equivalent circuit sensors shown in FIGS. 8 and 10, and a description thereof will be commonly done. While keeping the bias line at the bias value Vs in the photoelectric conversion mode, all the column signal lines Lc are connected to the reset reference potential 101 to reset the column signal lines. After that, the positive voltage Vgh is applied to the row selection line Lr1 to turn on the switches (1,1) to (1,4096) and reset the G electrodes of the photoelectric conversion elements of the first column to Vbt. Next, the row selection line Lr1 is set to the positive voltage Vg1 to turn off the switches (1,1) to (1,4096). All the pixels are reset by sequentially repeating row selection, thereby completing preparation for imaging. Since the above operation is the same as the signal charge read operation except whether signal charges are read, operation after this reset operation is called a “pre-read”. During this pre-read operation, all the row selection lines Lr can be simultaneously set to Vgh. In this case, however, when preparation for the read is completed, the signal line potential is largely shifted from the reset voltage Vbt, and a signal with high S/N radio can hardly be obtained. In the above-described example, the row selection lines Lr1 to Lr4096 are reset in this order. However, they can be reset in an arbitrary order under the control of the driver 62 on the basis of the setting of the image sensing controller 24. An X-ray exposure request is waited upon while repeating the pre-read operation. When an exposure request is generated, the pre-read operation is performed again to prepare for image acquisition, and X-ray exposure is waited. When preparation for image acquisition is completed, X-ray exposure is executed in accordance with an instruction from the image sensing controller 24. After X-ray exposure, signal charges are read from the photoelectric conversion elements 80. First, the voltage Vgh is applied to the row selection line Lr of a certain row (e.g., Lr1) of the photoelectric conversion element array to output accumulated charge signals to the signal lines Lc1 to Lc4096. Signals of 4,096 pixels are simultaneously read from the column signal lines Lc1 to Lc4096 in units of columns. Next, the voltage Vgh is applied to another row selection line Lr (e.g., Lr2) to output accumulated charge signals to the signal lines Lc1 to Lc4096. Signals of 4,096 pixels are simultaneously read from the column signal lines Lc1 to Lc4096 in units of columns. All pieces of image information are read by sequentially repeating this operation for the 4,096 column signal lines. During the operation, the charge accumulation time of each sensor corresponds to a time after the reset operation is ended, i.e., the TFT 82 in the pre-read mode is turned off until the TFT 82 is turned on to read charges. Hence, the accumulation time and timing change for each row selection. After an X-ray image is read, a correction image is acquired. This correction data is necessary to acquire a high-quality image and is used to correct the X-ray image. The basic image acquisition procedure is the same as described above except that no X-ray exposure is performed. The charge accumulation time in reading the X-ray image equals that in reading the correction image. When high-resolution image information is unnecessary, or the image data read speed need be high, all pieces of image information need not always be read. In accordance with the imaging method selected by the operator 21, the image sensing controller 24 sets a drive instruction of thinning, pixel averaging, or region extraction for the driver 62. To thin the image data, first, the row selection line Lr1 is selected, and in outputting signals from the column signal lines Lc, signal charges are read from one column while incrementing, e.g., n of Lc2n−1 (n: natural number) one by one from 0. After that, signals are read from one row while incrementing m of Lr2m−1 (m: natural number) one by one from 1. In this example, the number of pixels is thinned to 1/4. The driver 62 thins the number of pixels to 1/9, 1/16, or the like in accordance with a setting instruction from the image sensing controller 24. For pixel averaging, when the voltage Vgh is simultaneously applied to row selection lines Lr2m and Lr2m+1 during the above-described operation, TFTs 2m and 2n and TFTs 2m+1 and 2n are simultaneously turned on, so that analog addition of two pixels in the column direction can be performed. This means that not only addition of two pixels but also analog addition of a puerility plurality of pixels in the column signal line direction can be easily performed. For addition in the row direction, when adjacent pixels (Lc2n and Lc2n+1) are digitally added after A/D conversion output, the sum of 2×2 square pixels can be obtained together with the above analog addition. Hence, the data can be read at a high speed without wasting the X-ray irradiation. As another method of decreasing the total number of pixels to increase the read speed, the image read region is limited. To do this, the operator 21 inputs a necessary region from the operator interface 22, the image sensing controller 24 issues an instruction to the driver 62 on the basis of the input region, and the driver 62 changes the data read range and drives the two-dimensional detector array. In this embodiment, in the high-speed read mode, 1,024×1,024 pixels are read at 30 F/S. That is, in the entire region of the two-dimensional detector array, addition processing of 4×4 pixels is performed to thin the number of pixels to 1/16, and in the smallest range, an image is sensed in a 1,024×1,024 range without thinning. With this image sensing, a digital zoom image can be obtained. FIG. 13 is a timing chart including image sensing operation of the X-ray detector 52. The operation of the X-ray detector 52 will be described mainly with reference to FIG. 13. Reference numeral 701 denotes an image sensing request signal to the operator interface 22; 702, an actual X-ray exposure state; 703, an imaging request signal from the image sensing controller 24 to the driver 62 on the basis of an instruction from the operator 21; 704, an imaging ready signal of the X-ray detector 52; 705, a drive signal for the grid 54; 706, a power control signal in the X-ray detector 52; 707, a driven state of the X-ray detector (especially charge read operation from the photodetector array 58); and 708, an image processing or display state. Until a detector preparation request or imaging request is input by the operator 21, the driver 62 stands by in a power control off state, as indicated by 706. More specifically, referring to FIG. 11, the row selection lines Lr, column signal lines Lc, and bias line Lb are kept at an equipotential state (especially signal GND level) by a switch (not shown), and no bias is applied to the photodetector array 58. Alternatively, power supply including the signal read circuit 100, line selector 92, and bias power supply 84 or 85 may be cut off to keep the row selection lines Lr, column signal lines Lc, and bias line Lb at the GND potential. In accordance with an imaging preparation request instruction (701: 1st SW) from the operator 21 to the operator interface 22, the image sensing controller 24 outputs an instruction to shift the X-ray generator 40 to an imaging ready state and shift the X-ray detector 52 to an imaging preparation state. Upon receiving the instruction, the driver 62 applies a bias to the photodetector array 58 and repeats (refresh and) pre-read Fi. The request instruction is, e.g., the 1st SW of the exposure request switch to the X-ray generator (normally, rotor up for the tube or the like is started) or, when a predetermined time (several sec or more) is required by the X-ray detector 52 for imaging preparation, an instruction for starting preparation of the X-ray detector 52. In this case, the operator 21 need not consciously issue the imaging preparation request instruction to the X-ray detector 52. That is, when patient information or imaging information is input to the operator interface 22, the image sensing controller 24 may interpret it as a detector preparation request instruction and shift the X-ray detector 52 to the detector preparation state. In the detector preparation state, in the photoelectric conversion mode, to prevent a dark current from being gradually accumulated in the photodetection section 80 after the pre-read and the capacitor 80b (80c) from being held in the saturated state, the (refresh R and) pre-read Fi is repeated at a predetermined interval. This driving performed in the period when no actual X-ray exposure request is generated although the imaging preparation request from the operator 21 has been received, i.e., driving in which the pre-read Fi performed in the detector preparation state is repeated at a predetermined time interval T1 will be referred to as “idling drive” hereinafter. The period when the idling drive is performed in the detector preparation state will be referred to as an “idling drive period” hereinafter. How long the idling drive period continues is undefined in practical use. To minimize the read operation with load on the photodetector array 58 (especially the TFTs 82), the time interval T1 is set to be longer than that in the normal imaging operation, and the pre-read Fi dedicated to idling for which the ON time of the TFTs 82 is shorter than that in a normal read drive Fr. For a sensor that requires the refresh R, the refresh R is performed once for several times of pre-read Fi. X-ray image acquisition mainly performed by the X-ray detector 52 will be described next. Drive of the X-ray detector 52 in acquiring an X-ray image is mainly comprised of two image acquisition cycles. As indicated by 707, one is X-ray image acquisition drive, and the other is correction dark image acquisition drive. The drive cycles are almost the same except whether X-ray exposure operation is performed. Each drive cycle has three parts: an image sensing preparation sequence, charge accumulation (exposure window), and image read. X-ray image acquisition will be described below in accordance with the sequence. In accordance with an imaging request instruction (701: 2nd SW) from the operator 21 to the operator interface 22, the image sensing controller 24 controls imaging operation while synchronizing the X-ray generator 40 with the X-ray detector 52. In accordance with the imaging request instruction (701: 2nd SW), an imaging request signal is asserted provided to the X-ray detector at a timing represented by the X-ray exposure request signal 703. The driver performs predetermined image sensing preparation sequence drive operations as indicated by the imaging driven state 707 in response to the imaging request signal. More specifically, if the refresh is necessary, the refresh is performed. Then, a pre-read FR dedicated to the imaging sequence is performed a predetermined number of times, and a pre-read Fpf dedicated to the charge accumulation state is performed to shift the state to the charge accumulation state (image sensing window: T4). The number of times and time interval T2 of the pre-read Fp for the image sequence are based on values preset prior to the imaging request from the image sensing controller 24. Optimum drive is automatically selected depending on the image sensing portion or whether the request from the operator 21 represents priority on the operability or image quality. A period (T3) from the exposure request to the end of imaging preparation is required to be short in practical use. Hence, the pre-read Fp dedicated to the image sensing preparation sequence is performed. In addition, independently of the state of idling drive, when an exposure request is generated, the image sensing preparation sequence drive is immediately started to shorten the period (T3) from the exposure request to the end of imaging preparation, thereby improving the operability. In synchronism with the image sensing preparation of the photodetector array 58, the driver 62 starts moving the grid 54 to sense an image while setting the grid in an optimum moving state in synchronism with the actual X-ray exposure 702. In this case as well, the driver 62 operates on the basis of an optimum grid moving start timing and optimum grid moving speed that are set by the image sensing controller. In this embodiment, to eliminate the influence of vibration by the operation of the grid 54, the start of movement of the grid 54 is controlled such that a change in acceleration becomes small. In addition, in executing the pre-read Fpf dedicated to the charge accumulation state, which is readily affected by vibration, the grid 54 is controlled to exhibit uniform motion (still state or motion at uniform speed). When image sensing preparation of the X-ray detector 52 is ended, the driver 62 returns the X-ray detector ready signal 704 to the image sensing controller 24. On the basis of this signal transition, the image sensing controller 24 asserts provides the X-ray generation request signal 702 to the X-ray generator 40. The X-ray generator 40 generates X-rays while receiving the X-ray generation request signal 702. When a predetermined amount of X-rays is generated, the image sensing controller 24 negates the X-ray generation request signal 702, thereby notifying the X-ray detector 52 of the image acquisition timing. On the basis of this timing, the driver 62 immediately stops the grid 54 and starts operating the signal read circuit 100 that has been in the standby state. After the OFF time of the grid 54 and a predetermined wait time to stabilize the signal read circuit 100, when operation of reading image data from the photodetector array 58 and acquiring a raw image for the image processor 26 on the basis of the driver 62 is ended, the driver 62 shifts the signal read circuit 100 to the standby state again. In this embodiment, to eliminate the influence of vibration by the operation of the grid 54, the grid 54 is controlled to exhibit uniform motion (including the still state) before drive of an X-ray image acquisition frame Frxo that is most readily affected by vibration noise. Alternatively, a vibration sensor for measuring vibration may be attached to the X-ray detector 52, and the drive of the X-ray image acquisition frame Frxo may be started after confirming that the vibration by the grid or other factors has converged to a predetermined or less value. Subsequently, the X-ray detector 52 acquires a correction image. That is, the above imaging sequence for imaging is repeated to acquire a dark image without X-ray irradiation, and the correction dark image is transferred to the image processor 26. In the image sensing sequence, the X-ray exposure time or the like may slightly change between imaging cycles. However, when the same image sensing sequence is reproduced, including such differences, to acquire a rough image, an image with a higher quality can be obtained. However, the operation of the grid 54 is not limited to this. The grid 54 may be set still to suppress the influence of vibration in acquiring the rough image. In this case, after the image is almost acquired, the grid 54 is initialized at a predetermined timing that does not affect the image quality. FIG. 14 is a block diagram showing the flow of image data in the image processor 26. Reference numeral 801 denotes a multiplexer for selecting a data path; 802 and 803, X-ray image and rough image frame memories; 804, an offset correction circuit; 805, a gain correction data frame memory; 806, a gain correction circuit; 807, a defect correction circuit; and 808, other image procession circuits. An X-ray image acquired by the X-ray image acquisition frame Frxo in FIG. 13 is stored in the X-ray image frame memory 802 through the multiplexer 801. A correction image acquired in a correction image acquisition frame Frno is stored in the dark image frame memory 803 through the multiplexer 801. When the images are almost stored, offset correction (e.g., Frxo−Frno) is performed by the offset correction circuit 804. Subsequently, the gain correction circuit 806 performs gain correction (e.g., (Frxo−Frno)/Fg) using gain correction data Fg which is acquired and stored in the gain correction frame memory in advance. For the data transferred to the defect correction circuit 807, the image is continuously interpolated not to generate any sense of incompatibility at a dead pixel or connections between a plurality of panels of the X-ray detector 52, thus completing sensor-dependent correction processing resulted from the X-ray detector 52. In addition, the image procession circuits 808 execute general image processing such as grayscale processing, frequency processing, and emphasis processing. After that, the processed data is transferred to the display controller 32, and the image is displayed on the monitor 30. FIGS. 15 and 16 are views showing examples of the driving mechanism of the grid 54. A frame 901 holds the grid 54. A cam mechanism 902 for vibrating the frame 901 is connected to a rotating mechanism such as a grid driving motor (not shown). The grid driving motor (not shown) rotates and stops at the grid moving timing shown in FIG. 13 in accordance with an instruction from the driver 62, thereby moving the grid 54 in the direction indicated by the arrow or stopping the grid 54. An elastic member 1001 for moving the grid is formed from, e.g., a spring. A mechanism 1002 for moving the grid 54 to the home position is formed from, e.g., a solenoid. A braking mechanism 1003 stops the grid 54. In the initialization operation, the solenoid mechanism 1002 is operated to move the grid to the home position indicated by the broken line, and the grid is stopped by the braking mechanism 1003. The grid 54 is moved by canceling the braking on the basis of an instruction from the driver 62. The braking mechanism 1003 stops the grid in accordance with an instruction from the driver 62 at a predetermined timing. As described above, according to the X-ray image sensing apparatus of this embodiment, a satisfactory image can be easily and reliably obtained without any influence of vibration of the grid 54 or the like by a very simple arrangement. (Fourth Embodiment) In this embodiment, the internal arrangement of an X-ray room 10 is almost the same as in FIG. 7, and a description of common units will be omitted. Reference numeral 48b denotes part of an imaging bed 48 and represents a bed for a fluoroscopic system in FIG. 17. A fluoroscopic II (Image Intensifier) 1101 is controlled by an image sensing controller 24 to transfer an acquired image to an image processor 26 and then display the image on a monitor 30 or monitor dedicated to a fluoroscopic image, like an X-ray detector 52. The X-ray detector 52 is mainly located at a position B during a fluoroscopic image acquisition period and mainly moves to a position A during a simple image acquisition period. The X-ray detector 52 is moved in accordance with an instruction from the image sensing controller 24 to the imaging bed 48. The moving operation is performed by a mechanical means (not shown) for moving the X-ray detector 52. FIG. 18 is a timing chart including image sensing operation of the X-ray detector 52. The operation of the X-ray detector 52 of this embodiment will be described mainly with reference to FIG. 18. FIG. 18 is almost the same as FIG. 13, and different points will be mainly explained. Reference numeral 1201 denotes an image sensing request signal to an operator interface 22, which represents a simple X-ray imaging request state in FIG. 13 but a fluoroscopic/simple imaging request in this embodiment. Reference numeral 702 denotes an actual X-ray exposure state; 703, an imaging request signal from the image sensing controller 24 to a driver 62 on the basis of an instruction from an operator 21; 704, an imaging ready signal of the X-ray detector 52; 705, a drive signal for a grid 54; 706, a power control signal in the X-ray detector 52; 707, a driven state of the X-ray detector (especially charge read operation from a photodetector array 58); and 708, an image data transfer state or an image processing or display state. In addition, reference numeral 1202 denotes an X-ray output state for X-ray fluoroscopy; 1203, a concept of moving speed of the X-ray detector 52; and 1204, a position of the X-ray detector 52. While no request is received from the operator 21, the X-ray detector 52 stands by at the position B of the imaging bed 48. When a fluoroscopy request 1201 from the operator 21 is detected, fluoroscopic imaging is started (1202), and simultaneously, the X-ray detector 52 starts idling drive (707). When the operator 21 determines the object to be sensed and outputs a general imaging preparation request (1st SW: 1201), the X-ray generator 40 starts preparing for X-ray generation for general imaging and ends the preparation after a predetermined time. When the operator 21 inputs a general imaging request (2nd SW: 1201), the image sensing controller 24 starts X-ray image acquisition drive, instructs the X-ray detector 52 to prepare for imaging (703), stops fluoroscopic imaging (1202), and starts moving the X-ray detector 52 (1203 and 1204). In this embodiment, the image sensing controller 24 as a control means performs control such that the driver 62 operates the photodetector array 58 in a steady state with a converged vibration, i.e., at a predetermined speed (uniform speed) without acceleration during an operation period related to the read of the X-ray detector 52 as a detection means. At the start of moving, moving is started while continuously changing the acceleration not to increase the vibration. Since a time T3 until the end of imaging preparation of the X-ray detector 52 is known in advance, the X-ray detector 52 is completely moved to the general imaging position A within a time according to the time T3. However, in the driven state 707, when vibration occurs at the time of a frame Fpf immediately before the end of imaging preparation, noise is readily superposed on the image. To prevent this, immediately after the end of the frame Fpf, stop operation of the X-ray detector 52 is started, and until this time, the X-ray detector 52 is controlled to move at a constant speed without generating any acceleration. When preparation is ended, the X-ray exposure 702 is performed. Immediately after exposure is ended, an X-ray image acquisition frame Frxo is driven to acquire an X-ray image (707). After the end of X-ray exposure 702, fluoroscopic imaging should be started as soon as possible. After the drive of the X-ray image acquisition frame Frxo is ended, correction dark image acquisition drive is started, and simultaneously, movement of the X-ray detector 52 from the position A to the position B is immediately started (1204). As in the preceding X-ray image acquisition drive, movement is started while continuously changing the acceleration not to increase the vibration. Since the time T3 until the end of imaging preparation of the X-ray detector 52 is known in advance, as in the X-ray image acquisition drive, the X-ray detector 52 is completely moved to the general imaging position B within a time according to the time T3. Contents related to the frame Fpf immediately before the end of imaging preparation are also the same as in the X-ray image acquisition drive. When movement from the position A to the position B is ended, fluoroscopic imaging is resumed, and the fluoroscopic image can be redisplayed from this time. After that, a rough image acquisition frame Frno is driven at a predetermined timing to acquire a rough image. The general image is subjected to predetermined image processing and then displayed on the monitor 30. For the control, as in the third embodiment, a sensor (not shown) capable of detecting a vibration amount may be arranged in or near the X-ray detector 52, and a predetermined read (e.g., the X-ray image acquisition frame Frxo, dark image acquisition frame Frno, or frame Fpf immediately before the end of imaging preparation) may be started when the vibration becomes equal to or smaller than a predetermined value. For the control, except a predicted period of vibration in the driver 62, an operation period related to the image read of the X-ray detector 52 may be set, and drive related to image acquisition may be performed during this operation period. As described above, according to the X-ray image sensing apparatus of this embodiment, a satisfactory image can be easily and reliably obtained without any influence of vibration of the X-ray detector 52 or the like by a very simple arrangement. (Fifth Embodiment) In this embodiment, the internal arrangement of an X-ray room 10 is almost the same as in FIG. 7, and a description of common units will be omitted. Reference numeral 48b denotes part of an imaging bed 48 and represents a bed for a fluoroscopic system in FIG. 17. A fluoroscopic II (Image Intensifier) 1101 is controlled by an image sensing controller 24 to transfer an acquired image to an image processor 26 and then display the image on a monitor 30 or monitor dedicated to a fluoroscopic image, like an X-ray detector 52. The X-ray detector 52 is mainly located at a position B during a fluoroscopic image acquisition period and mainly moves to a position A during a simple image acquisition period. The X-ray detector 52 is moved in accordance with an instruction from the image sensing controller 24 to the imaging bed 48. The moving operation is performed by a mechanical means (not shown) for moving the X-ray detector 52. FIG. 19 is a timing chart including image sensing operation of the X-ray detector 52. The operation of the X-ray detector 52 of this embodiment will be described mainly with reference to FIG. 19. FIG. 19 is almost the same as FIG. 13, and different points will be mainly explained. Reference numeral 1201 denotes an image sensing request signal to an operator interface 22, which represents a simple X-ray imaging request state in FIG. 13 but a fluoroscopic/simple imaging request in this embodiment. Reference numeral 702 denotes an actual X-ray exposure state; 703, an imaging request signal from the image sensing controller 24 to a driver 62 on the basis of an instruction from an operator 21; 704, an imaging ready signal of the X-ray detector 52; 705, a drive signal for a grid 54; 706, a power control signal in the X-ray detector 52; 707, a driven state of the X-ray detector (especially charge read operation from a photodetector array 58); and 708, an image data transfer state or an image processing or display state. In addition, reference numeral 1202 denotes an X-ray output state for X-ray fluoroscopy; 1203, a concept of moving speed of the X-ray detector 52; and 1204, a position of the X-ray detector 52. While no request is received from the operator 21, the X-ray detector 52 stands by at the position B of the imaging bed 48. When a fluoroscopy request 1201 from the operator 21 is detected, fluoroscopic imaging is started (1202), and simultaneously, the X-ray detector 52 starts idling drive (707). When the operator 21 determines the object to be sensed and outputs general imaging preparation request (1st SW: 1201), the X-ray generator 40 starts preparing for X-ray generation for general imaging and ends the preparation after a predetermined time. When the operator 21 inputs a general imaging request (2nd SW: 1201), the image sensing controller 24 starts X-ray image acquisition drive, instructs the X-ray detector 52 to prepare for imaging (703), stops fluoroscopic imaging (1202), and starts moving the X-ray detector 52 (1203 and 1204). In this embodiment, the image sensing controller 24 as a control means performs control such that the driver 62 operates the photodetector array 58 in a steady state with a converged vibration, i.e., at a predetermined acceleration during an operation period related to the read of the X-ray detector 52 as a detection means. When a desired acceleration is obtained, the motion preferably shifts to uniformly accelerated motion. In general control, actually, the acceleration abruptly changes (arrows in 1205). Since a time T3 until the end of imaging preparation of the X-ray detector 52 is known in advance, the X-ray detector 52 is completely moved to the general imaging position A within a time according to the time T3. When the movement and frame Fpf are synchronously ended, the time from the 2nd SW to the X-ray exposure 702 can be minimized. Hence, a frame Fpf is required to be ended at the time of predetermined deceleration (negative acceleration). In the driven state 707, when vibration occurs at the time of the frame Fpf immediately before the end of imaging preparation, noise is readily superposed on the image. To prevent this, the frame Fpf is acquired at a timing when the vibration due to the abrupt change in acceleration has converged, and the X-ray detector 52 is stopped immediately after the end of the frame Fpf. When preparation is ended, the X-ray exposure 702 is performed. After the end of X-ray exposure 702, fluoroscopic imaging should be started as soon as possible. Hence, movement of the X-ray detector 52 from the position A to the position B is started immediately after the end of exposure (1204). Simultaneously, the X-ray image acquisition frame Frxo is driven at the time of uniform acceleration (or uniformly accelerated motion) at the timing when the vibration due to a change in acceleration converges, thereby acquiring an X-ray image. After the end of the X-ray image acquisition frame Frxo, correction dark image acquisition drive is started. Since the time T3 until the end of imaging preparation of the X-ray detector 52 is known in advance, as in the X-ray image acquisition drive, the X-ray detector 52 is completely moved to the general imaging position B within a time according to the time T3. Contents related to the frame Fpf immediately before the end of imaging preparation are also the same as in the X-ray image acquisition drive. When movement from the position A to the position B is ended, fluoroscopic imaging is resumed, and the fluoroscopic image can be redisplayed from this time. After that, a dark image acquisition frame Frno is driven at a predetermined timing to acquire a dark image. The general image is subjected to predetermined image processing and then displayed on the monitor 30. For the control, as in the third embodiment, a sensor (not shown) capable of detecting a vibration amount may be arranged in or near the X-ray detector 52, and a predetermined read (e.g., the X-ray image acquisition frame Frxo, dark image acquisition frame Frno, or frame Fpf immediately before the end of imaging preparation) may be started when the vibration becomes equal to or smaller than a predetermined value. For the control, except a predicted period of vibration in the driver 62, an operation period related to the image read of the X-ray detector 52 may be set, and drive related to image acquisition may be performed during this operation period. As described above, according to the X-ray image sensing apparatus of this embodiment, a satisfactory image can be easily and reliably obtained without any influence of vibration of the X-ray detector 52 or the like by a very simple arrangement. Three embodiments, the third to fifth embodiments, have been described above. The present invention is applied to a cooling fan or any other potential vibration source. The present invention also incorporates a case wherein to operate various devices to implement the functions of the above-described embodiments, software program codes for implementing the functions of the embodiments are supplied to a computer in an apparatus or system connected to the devices, and the devices are operated in accordance with a program stored in the computer (or CPU or MPU) of the system or apparatus. In this case, the software program codes themselves implement the functions of the above-described embodiments, and the program codes themselves and a means for supplying the program codes to the computer, e.g., a storage medium which stores such program codes constitute the present invention. As the storage medium for storing such program codes, for example, a floppy disk, hard disk, optical disk, magnetooptical disk, CD-ROM, magnetic tape, nonvolatile memory card, ROM, or the like can be used. The functions of the above-described embodiments are implemented when the supplied program codes are executed by the computer. In addition, even when the functions of the above-described embodiments are cooperatively implemented by an operating system (OS) running on the computer or another application software, the program codes are included in the embodiments of the present invention. The functions of the above-described embodiments are also implemented when the supplied program codes are stored in the memory of a function expansion board inserted into the computer or a function expansion unit connected to the computer, and the CPU of the function expansion board or function expansion unit performs part or all of actual processing on the basis of the instructions of the program codes. As has been described above, according to the third to fifth embodiments, a radiation image sensing apparatus (image sensing apparatus) and image sensing method which can easily and reliably obtain a satisfactory image without any influence of vibration or a grid or X-ray detection means by a very simple arrangement can be provided. The present invention is not limited to the above embodiments and various changes and modifications can be made within the spirit and scope of the present invention. Therefore, to apprise the public of the scope of the present invention, the following claims are made.
	summary
06212255&	summary	BACKGROUND OF THE INVENTION X-Ray irradiation of blood plasma is one of the methods sanctioned by the U.S. Food and Drug Administration for providing a product which diminishes the chance of transfusion-induced diseases. For this purpose, the radiation dose and dose distributions that may occur from X-ray sources must be controlled accurately for meeting regulatory requirements. X-ray irradiation for sterilization has several advantages over gamma ray irradiation, electron beam application and other types of blood purification. First, X-rays can be accurately controlled in application and secondly, equipment for providing the X-rays is relatively safe, and also, the equipment for providing the X-rays is comparatively inexpensive as compared to the other types of blood purification. SUMMARY OF INVENTION The inventive blood irradiator provides a uniform dose of X-ray beam irradiation for a blood plasma contained in a blood transfusion bag. In one embodiment, the bag is placed in a selected cannister for receiving the X-ray beam, and the system includes two X-ray tubes positioned to irradiate the bag from opposite sides to provide a uniform radiation to the blood in the bag. The foregoing features and advantages of the present invention will be apparent from the following more particular description of the invention. The accompanying drawings, listed herein below, are useful in explaining the invention.
	claims	1. A method of assisting with authenticating a workpiece, the method comprising:(a) generating ions;(b) accelerating the ions in an accelerator with an energy of at least 100 A-MeV and a beam power of at least 1 kW;(c) creating an accelerated isotope from the accelerated ions; and(d) implanting the accelerated isotope in the workpiece to assist with the authenticating of the workpiece. 2. The method of claim 1, wherein the accelerating of the ions occurs by using a facility comprising a superconducting cyclotron accelerator. 3. The method of claim 2, wherein the generating of the ions occurs by using one of: (a) an electron cyclotron resonance source or (b) an electron beam ion source. 4. The method of claim 2, wherein the generating of the ions occurs by using one of: (a) microwaves in a low pressure gas, or (b) thermionic emissions of electrons to ionize a base material in its gaseous state. 5. The method of claim 2, wherein the ions are rare heavy ions. 6. The method of claim 1, further comprising using a gamma ray detector with keV energy resolution to nondestructively identify at least one of: (a) the isotope, or (b) a position of the isotope, to assist in the authenticity of the workpiece after the implanting step. 7. The method of claim 1, further comprising placing a removable mask, having a unique hole pattern, against the workpiece and emitting the accelerated isotope through the hole pattern before the implanting step. 8. The method of claim 1, further comprising using different combinations of rare isotopes to create customizable workpiece identifiers in additional workpieces. 9. The method of claim 1, further comprising applying a visual marker to the workpiece adjacent to a location of the isotope implantation. 10. The method of claim 1, wherein the creating of the accelerated isotope comprises fragmenting the accelerated ions to create a fragmented isotope and then re-accelerating the fragmented isotope. 11. The method of claim 1, wherein the workpiece includes a painting on canvas and the isotope penetrates into and is implanted inside the workpiece between 5 mm and 1 micron deep from an entry surface thereof. 12. The method of claim 1, wherein the workpiece is metallic and the isotope penetrates into and is implanted inside the workpiece between 5 mm and 1 micron deep from an entry surface thereof. 13. A method of assisting with authenticating workpieces, the method comprising:(a) generating ions;(b) accelerating the ions in a superconducting cyclotron accelerator;(c) creating a first combination of rare isotopes and a second combination of rare isotopes;(d) transmitting the first combination of rare isotopes through holes in at least one removable mask toward a first of the workpieces;(e) transmitting the second combination of rare isotopes through the holes in the at least one removable mask toward a second of the workpieces; and(f) causing the first and second combinations of rare isotopes to penetrate into the respective workpieces between 5 mm and 1 micron deep from an entry surface of each of the workpieces adjacent the mask, wherein the first and second combinations of rare isotopes are different, which creates unique authenticating indications. 14. The method of claim 13, wherein each of the rare isotopes has a measurable and precise alpha or gamma decay emission, but not a beta decay emission. 15. The method of claim 13, wherein the generating of the ions occurs by using one of: (a) an electron cyclotron resonance source or (b) an electron beam ion source. 16. The method of claim 13, wherein the generating of the ions occurs by using one of: (a) microwaves in a low pressure gas, or (b) thermionic emissions of electrons to ionize a base material in its gaseous state. 17. The method of claim 13, further comprising using an isotope ratio mass spectrometer to nondestructively identify at least one of: (a) the first or second combinations of rare isotopes, or (b) a position of the first or second combinations of rare isotopes, to assist in the authenticity of the workpieces after the implanting step. 18. The method of claim 13, further comprising applying a visual marker to each of the workpieces adjacent to a location of implantation of the first or second combinations of rare isotopes. 19. A workpiece comprising:(a) a pre-made workpiece substrate;(b) a visual marker; and(c) rare isotopes internally located within the pre-made substrate adjacent the visual marker, the rare isotopes providing a customized identifier based on at least one of: a pattern, quantity, isotope combinations, or half-life;(d) the rare isotopes having:the half-life of at least three months;a precise and measurable alpha or gamma decay emission;a unique isotope signature; and wherein the rare isotopes are a combination of rare isotopes including at least one of: 14864Gd, 19476Os, 6026Fe, 12650Sn, 22888Ra, or 21082Pb. 20. The workpiece of claim 19, wherein:the combination of the rare isotopes is arranged in a unique pattern implanted within the substrate between 5 mm and 1 micron deep from an entry surface thereof.
	abstract	A method for retracting in-core instrument thimble tubes from the reactor core prior to refueling a nuclear reactor with top mounted instrumentation. The apparatus includes a penetration flange interposed between the head flange and the reactor vessel flange through which the instrumentation cabling passes. The penetration flange is connected to the upper internals and is raised relative thereto to retract instrumentation thimbles from the core prior to removal of the upper internals from the reactor vessel for refueling. The penetration flange is removed from the vessel with the upper internals.
	claims	1. An ion optical assembly comprising:a mounting body having a front side and a back side;a front securing member having a threaded surface and a contact face;a front member having a threaded opening configured to accept the threaded surface of the front securing member, the front member being attached to the mounting body by at least one attachment member; anda first plurality of ion optical elements disposed between the front side of the mounting body and the front member,each ion optical element of the first plurality having a recess structure adapted to receive a complimentary registration structure, a registration structure aligning an ion optical element of the first plurality with respect to at least one other ion optical element of the first plurality when said registration structure is registered in a complimentary recess structure by application of a compressive force by the front securing member against the first plurality of ion optical elements;wherein the threaded opening of the front member is configured such that when the threaded surface of the front securing member is engaged in the threaded opening of the front member, the contact face of the front securing member can contact an ion optical element of the first plurality and apply a compressive force against the first plurality of ion optical elements. 2. The ion optical assembly of claim 1, further comprising:a back securing member having a threaded surface and a contact face;a back member having a threaded opening configured to accept the threaded surface of the back securing member, the back member being attached to the mounting body by at least one attachment member; anda second plurality of ion optical elements disposed between the back side of the mounting body and the back member,each ion optical element of the second plurality having a recess structure adapted to receive a complimentary registration structure, a registration structure aligning an ion optical element of the second plurality with respect to at least one other ion optical element of the second plurality when said registration structure is registered in a complimentary recess structure by application of a compressive force by the back securing member against the second plurality of ion optical elements;wherein the threaded opening of the back member is configured such that when the threaded surface of the back securing member is engaged in the threaded opening of the back member, the contact face of the back securing member can contact an ion optical element of the second plurality and apply a compressive force against the second plurality of ion optical elements. 3. The ion optical assembly of claim 1, wherein the threaded opening comprises one or more of a substantially continuous helical ridge, a substantially continuous spiral ridge, an interrupted helical ridge, an interrupted spiral ridge, and combinations thereof. 4. The ion optical assembly of claim 3, wherein the threaded surface of the front securing member is engaged in the threaded opening of the front member by screwing the front securing member into the threaded opening of the front member. 5. The ion optical assembly of claim 1, wherein the threaded opening comprises one or more of a substantially continuous circular ridge, an interrupted circular ridge, and combinations thereof. 6. The ion optical assembly of claim 5, wherein the threaded surface of the front securing member is engaged in the threaded opening of the front member by pushing the front securing member into the threaded opening of the front member. 7. The ion optical assembly of claim 1, wherein the contact surface of the front securing member is beveled and the ion optical element contacted by the front securing member has a beveled surface adapted to receive said beveled contact surface. 8. The ion optical assembly of claim 1, wherein the front member is attached to the mounting body by three attachment members. 9. The ion optical assembly of claim 1, wherein the at least one attachment members comprises a rod. 10. The ion optical assembly of claim 1, wherein the mounting body comprises a region for performing ion fragmentation. 11. The ion optical assembly of claim 1, wherein the region for performing ion fragmentation comprises a collision cell. 12. The ion optical assembly of claim 1, wherein the front securing member is self locking in the front member upon application of a pre-selected torque. 13. A system for mounting and aligning ion optic components, comprising:a mounting base having a mounting surface and a back surface opposite the mounting surface, the mounting surface having a plurality of pairs of protrusions protruding from the mounting surface and one or more mounting structures associated with each pair of protrusions;at least one electrical connection element associated with each pair of protrusions, the connection elements passing through the mounting base from the back surface to the mounting surface;two or more ion optic component supports, each ion optic component support having a pair of recesses configured to receive one or more of the plurality of pairs of protrusions;such that when the pair of recesses of an ion optic component support is brought into registration with the corresponding pair of protrusions by mounting an ion optic component to the mounting base using the one or more mounting structures associated with the pair of protrusions, an ion optics component mounted in said ion optic component support is substantially aligned with another ion optics component so mounted and an electrical connection site on said ion optics component is proximate to a corresponding electrical connection element associated with said corresponding pair of protrusions. 14. The system of claim 13, wherein one of the ion optic component supports comprises a mounting body having a region for performing ion fragmentation. 15. The system of claim 14, wherein the region for performing ion fragmentation comprises a collision cell. 16. The system of claim 14, wherein an ion optics assembly is mounted to the mounting body, wherein the ion optics assembly comprises:a front securing member having a threaded surface and a contact face;a front member having a threaded opening configured to accept the threaded surface of the front securing member, the front member being attached to the mounting body by at least one attachment member; anda first plurality of ion optical elements disposed between a front side of the mounting body and the front member,each ion optical element of the first plurality having a recess structure adapted to receive a complimentary registration structure, a registration structure aligning an ion optical element of the first plurality with respect to at least one other ion optical element of the first plurality when said registration structure is registered in a complimentary recess structure by application of a compressive force by the front securing member against the first plurality of ion optical elements;wherein the threaded opening of the front member is configured such that when the threaded surface of the front securing member is engaged in the threaded opening of the front member, the contact face of the front securing member can contact an ion optical element of the first plurality and apply a compressive force against the first plurality of ion optical elements. 17. The system of claim 16, wherein the ion optics assembly comprises:a back securing member having a threaded surface and a contact face;a back member having a threaded opening configured to accept the threaded surface of the back securing member, the back member being attached to the mounting body by at least one attachment member; anda second plurality of ion optical elements disposed between a back side of the mounting body and the back member,each ion optical element of the second plurality having a recess structure adapted to receive a complimentary registration structure, a registration structure aligning an ion optical element of the second plurality with respect to at least one other ion optical element of the second plurality when said registration structure is registered in a complimentary recess structure by application of a compressive force by the back securing member against the second plurality of ion optical elements;wherein the threaded opening of the back member is configured such that when the threaded surface of the back securing member is engaged in the threaded opening of the back member, the contact face of the back securing member can contact an ion optical element of the second plurality and apply a compressive force against the second plurality of ion optical elements. 18. The system of claim 13, wherein the plurality of pairs of protrusions are configured such that only one orientation of an ion optic component support will enable the pair of recesses of the ion optic component support to be brought into registration with the corresponding pair of protrusions. 19. The system of claim 13, wherein the pairs of protrusions are configured to have different shapes for ion optic component supports for different ion optic components. 20. An ion optical assembly comprising:a mounting body having a front side and a back side, and a region disposed therein for performing ion fragmentation by collision induced dissociation;a front securing member having a threaded surface and a contact face;a front member having a threaded opening configured to accept the threaded surface of the front securing member, the front member being attached to the mounting body by at least one attachment member;a first plurality of ion optical elements disposed between the front side of the mounting body and the front member,each ion optical element of the first plurality having a recess structure adapted to receive a complimentary registration structure, a registration structure aligning an ion optical element of the first plurality with respect to at least one other ion optical element of the first plurality when said registration structure is registered in a complimentary recess structure by application of a compressive force by the front securing member against the first plurality of ion optical elements;wherein the threaded opening of the front member is configured such that when the threaded surface of the front securing member is engaged in the threaded opening of the front member, the contact face of the front securing member can contact an ion optical element of the first plurality and apply a compressive force against the first plurality of ion optical elements;a back securing member having a threaded surface and a contact face;a back member having a threaded opening configured to accept the threaded surface of the back securing member, the back member being attached to the mounting body by at least one attachment member; anda second plurality of ion optical elements disposed between the back side of the mounting body and the back member,each ion optical element of the second plurality having a recess structure adapted to receive a complimentary registration structure, a registration structure aligning an ion optical element of the second plurality with respect to at least one other ion optical element of the second plurality when said registration structure is registered in a complimentary recess structure by application of a compressive force by the back securing member against the second plurality of ion optical elements;wherein the threaded opening of the back member is configured such that when the threaded surface of the back securing member is engaged in the threaded opening of the back member, the contact face of the back securing member can contact an ion optical element of the second plurality and apply a compressive force against the second plurality of ion optical elements.
	claims	1. A system for an intensity-modulated proton therapy of a predetermined volume within an object, the system comprising:a) a proton source for generating a proton beam being adjustable with respect to beam intensity;b) a degrader being optionally disposed in the proton beam for attenuating energy of protons in the proton beam to a desired proton energy in the proton beam;c) a beam transport system being supported by a support frame pivotable around an optical axis; said beam transport system including:d) a plurality of proton beam bending and/or focusing units;e) a beam nozzle having an outlet for the proton beam for penetrating a predetermined volume of the object;f) a beam bending magnet being disposed upstream of said nozzle; andg) a couple of sweeper magnets being disposed upstream of said beam bending magnet for sweeping the proton beam in both lateral directions before the proton beam enters into said beam bending magnet,h) said beam nozzle defining a cross-sectional scanning area substantially perpendicular to the proton beam in the range of 10 cm×30 cm, andi) said sweeper magnets and said beam bending magnet being controlled to substantially provide a parallel beam orientation over a complete cross-sectional scanning area and for delivering a substantially 1:1 beam image of the proton beam before entering into said beam bending magnet as compared to the beam image after the bending. 2. The system according to claim 1, wherein a preabsorber body is optionally disposed between the outlet of the nozzle and the object. 3. The system according to claim 1, wherein the cross-sectional scanning area is oriented substantially perpendicular to a longitudinal axis of the proton beam, and a moving mechanism for the preabsorber body is provided which is remotely controllable to move the preabsorber body from a parking position into an absorbing position to cover the complete scanning area. 4. The system according to claim 2, wherein the preabsorber body comprises at least one of carbon and beryllium. 5. The system according to claim 1, wherein a collimator is optionally pivoted into the proton beam upstream of the beam bending magnet; said collimator being movable radially and/or azimuthally. 6. The system according to claim 1, wherein the object is supported by a table which is optionally movable in a plane being substantially perpendicular to the proton beam by a table driving unit, whereby the movement of the table is detected by the table driving unit to control a deflection of the proton beam in a respective sweeper magnet for annihilating a relative shift between the object and the proton beam during dose painting. 7. A process for an intensity-modulated proton therapy of a predetermined volume within an object; comprising the steps of:a) discretising the predetermined volume into a number of iso-energy layers each corresponding to a determined energy of the proton beam;b) determining a final target dose distribution for each iso-energy layer; andc) applying at least a predetermined part of the final target dose distribution by parallel beam scanning by controlling respective beam sweepers thereby for scanning one iso-energy layer after the other using an intensity-modulated proton beam while scanning a predetermined iso-energy layer. 8. The process according to claim 7, including the step of multiple painting of the respective iso-energy layers, so that each painting delivers a predetermined part of the final target dose distribution. 9. The process according to claim 7, including the step of geometrically field patching by moving a support table continuously, thereby simultaneously compensating the displacement of the motion of the support table with an offset applied to the beam sweepers. 10. The process according to claim 7, including the step of magnetically scanning at each iso-energy layer along the contour of a target volume and on similar equidistant contours in an interior of the target volume, thereby shaping the dose by using beam intensity modulation along the contours. 11. The process according to claim 7, including the step of applying imaged collimation on the scanned beam by using a collimator block being radially and/or azimuthally moved into the proton beam at a coupling point of a beam transport system. 12. The process according to claim 7, including the step of controlling the beam sweepers and beam bending magnet to substantially provide a parallel beam orientation over a complete cross-sectional scanning area and to deliver a substantially 1:1 beam image of a proton beam before entering into the beam bending magnet as compared to the beam image after the bending.
	abstract	A lithographic apparatus includes a radiation system configured to form a projection beam of radiation. The radiation system includes a radiation source that emits radiation, a filter system for filtering debris particles out of the radiation beam, and an illumination system configured to condition a radiation beam. A projection system is configured to project the projection beam of radiation onto a substrate. The filter system includes a plurality of foils for trapping the debris particles. At least one foil includes at least two parts that have a mutually different orientation and that are connected to each other along a substantially straight connection line. Each of the two parts substantially coincide with a virtual plane that extends through a predetermined position that substantially coincides with the radiation source. The straight connection substantially line coincides with a virtual straight line that also extends through the predetermined position.
	summary
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	claims	1. A CT system comprising: rotatable gantry having an opening defining a scanning bay; a movable table configured to translate a subject to be scanned along a first axis within the scanning bay; an x-ray projection source configured to project x-rays projected toward the subject; a pre-subject filter to filter x-rays projected toward the subject, the filter having a variable attenuation profile; and a computer programmed to: determine an attenuation pattern of the subject; translate the filter along the first axis as a function of the attenuation pattern of the subject; and acquire imaging data of the subject. 2. The CT system of claim 1 wherein the computer is further programmed to translate the filter in a transverse direction as a function of the attenuation pattern of the subject. claim 1 3. The CT system at claim 2 wherein the computer is further programmed to position the filter as a function of the attenuation pattern of the subject to reduce radiation exposure to dose reduction regions of the subject. claim 2 4. The CT system of claim 3 wherein the dose reduction regions include anatomical regions sensitive to radiation. claim 3 5. The CT system of claim 1 wherein the computer is further programmed to determine the attenuation pattern of the subject from a set of patient projections. claim 1 6. The CT system of claim 1 wherein the computer is further programmed to move the filter as a function of gantry rotation. claim 1 7. A radiographic imaging system comprising: a scanning bay; a movable table configured to move a subject to be scanned fore and aft along a first direction within the scanning bay; an x-ray projection source configured to project x-rays in an x-ray beam toward the subject; a pair of cam filters formed of attenuating matter, wherein each cam filter has a length and an attenuation profile that varies as a function of filter length and wherein the attenuation profile of each filter is a function of filter thickness; and a computer programmed to: determine a region-of-interest of the subject; position the pair of cam filters to limit x-ray exposure outside the region-of-interest; and translate at least one of the filters in the first direction to either increase or decrease x-ray exposure to the region of interest. 8. The radiographic imaging system of claim 7 wherein the pair of cam filters is oriented in an x-axis. claim 7 9. The radiographic imaging system of claim 7 wherein each cam filter has an elliptical shape. claim 7 10. The radiographic imaging system of claim 7 wherein the computer is further programmed to decrease a space between the pair of filters to narrow the x-ray beam and increase the space between the pair of filters to widen the x-ray beam. claim 7
	description	This application claims priority to U.S. Provisional Patent Application No. 61/785,037, filed on Mar. 14, 2013, the entire contents of which are hereby incorporated by reference herein. The present disclosure relates to material testing. More particularly, the present disclosure relates to a density gauge having a radioactive source and a detector for testing material density. Measuring one or more characteristics of a construction material is important for insuring integrity of a given building project. For example, in the road construction industry, it is important to determine the density of the underlying soil surface before, during, and after layment of asphalt or concrete, and additionally for determining the density of the asphalt or concrete during the laying process. If the density is less than a desired amount, additional rolling or compacting of the soil, asphalt or concrete may be required. There are many methods for determining the density of the road surface, however, the most efficient and accurate method for determining density has been by using a nuclear source and counting or analyzing the nuclear radiation with some type of nuclear detector. Using a nuclear source has the disadvantage of subjecting use of nuclear sources to regulatory oversight. Conventional nuclear-based density gauges may have various disadvantages associated therewith, including shielding required to limit accidental or inadvertent exposure to the nuclear source. Accordingly, new and improved nuclear density gauges are needed. This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description of Illustrative Embodiments. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. According to one or more embodiments disclosed herein, a gauge is provided. The gauge includes a source housing, detector, and a base that carries the source housing and detector. According to one or more embodiments disclosed herein, the gauge includes a control mechanism by which a source is deployed. According to one or more embodiments disclosed herein, the gauge includes planned breakage area by which the source housing is attached to the base. According to one or more embodiments disclosed herein, the gauge includes a shielding material such as lead encased in a rugged housing including steel or tungsten. According to one or more embodiments disclosed herein, the source has an exposure rate less than a predetermined threshold. According to one or more embodiments disclosed herein, the gauge surface has an exposure rate less than a predetermined threshold. According to one or more embodiments disclosed herein, the volume surrounding the gauge has an exposure rate less than a predetermined threshold. According to one or more embodiments disclosed herein, the partial area incorporating the steradian immediate the gauge has an exposure rate less than a predetermined threshold. While the disclosure of the technology herein is presented with sufficient details to enable one skilled in this art to practice the invention, it is not intended to limit the scope of the disclosed technology. The inventors contemplate that future technologies may facilitate additional embodiments of the presently disclosed subject matter as claimed herein. Moreover, although the term “step” may be used herein to connote different aspects of methods employed, the term should not be interpreted as implying any particular order among or between various steps herein disclosed unless and except when the order of individual steps is explicitly described. According to one or more embodiments, a gauge is illustrated in FIG. 1 and generally designated 10. In the particular embodiment that is illustrated, the gauge 10 includes a detector 12 and a base 14 that carries the detector 12. The detector 12 may be any appropriately configured device that is able to detect one or more measurements related to a nuclear source. For example, detector 12 may be a Geiger Mueller tube, a scintillation detector, and the like. Uses for a gauge 10 according to various embodiments described herein include but are not limited to measuring density and moisture of compacted soils, asphalt, and concrete in roadway and industrial scale parking lots. Further uses include determining moisture and density of soils, soil bases, aggregate, concrete, and asphaltic concrete without the use of core samples. With additional reference to FIG. 1, the gauge 10 further includes a source rod housing 16 (that is carried by the base 14. The base/source housing 21 may define a shield material 20 circumferentially extending inwards. The shield material 20 may be any appropriately configured or selected material capable of shielding nuclear radiation, including, without limitation, lead, tungsten, and the like. A guide rod or enclosure 18 may be provided for guiding and indexing the source rod housing 16. A source rod 22 is positioned within the source rod housing 16 in the gauge 10 illustrated in FIG. 1, FIG. 2, and FIG. 3. The source rod 22 carries a source 24 that is translatable between a shielded position within the source housing 21 and a measuring position external of and extended out of the source housing 21. The source 24 may be any appropriately configured source, such as, for example a source that contains 0.00333 GBq (0.09 mCi) of Cs-137. In that or other embodiments, Co-60 is provided as a source. Cs-137 has the advantage of a having a lower ionizing energy than that of Co-60 which has the advantage of a shorter half-life. The source 24 may be carried within a multiple of source shields 26. The source shield 26 may be made of any appropriately shielding material, such as, for example, tungsten carbide. The source rod 22 may further include a shield material 30 spaced-downwardly from the source 24. In this manner, the source 24 is encased by a shield material in all directions when in the source housing 21, specifically, the shield material 20 enclosing around a circumference of the source 24, the source shield 26 on an upward facing portion of the source 24 and the shield material 30 on a downward facing portion of the source 24. The source 24 from the factory is also doubly encapsulated in stainless steel. There is also lead shielding in the base of the gauge 10, but this is more for isolating the detectors in the background mode, and tuning the response in the standard mode. As illustrated in FIG. 2 and with further reference to FIG. 4, the housing/tower casing 16 defines a failure zone 32 about a bottom thereof. This failure zone 32 is provided such that the base 14 separates from the source housing 21 about the failure zone 32 during an impact. In this manner, the source 24 remains in the source housing 16 and remains encapsulated in all directions by shield material 20, source shield 26, and shield material 30 when in the shielded position. As such, during a failure where the source housing 16 breaks off from the base 14, the source 24 remains entirely shielded and limits any radiation exposure that would otherwise occur. Shield material 30 may be lead, tungsten, or tungsten carbide, or any other appropriate material. FIG. 4 shows an accelerometer 28 that may be provided, illustrated in this embodiments about base 14, for measuring acceleration of the gauge 10 in order to detect mishandling thereof. As will be discussed in further detail, the information related to acceleration may be used to provide one or more alerts to an operator, service technician, or the like. The failure zone 32 is illustrated defining a cutout 34 that extends into the housing 16 and a corresponding cutout 38 defined in the shield material 30. In this manner, the cutout 34 provides for an area of decreased structural integrity and provides for a clean break plane of the source housing 16 about the base 14 during an impact. The cutout 34 may extend around an entire circumferential periphery of the source housing 16 as illustrated. Cutout 38 may extend entirely through shield material 30, thereby leaving a lower portion of shield material 33 that is configured to break off with the base 14. Breakaway fasteners then would connect the lower portion of the shield to the upper portion. Though cutout 34 is illustrated as forming the failure zone, any manner of other structural, material, or other designs could be employed. For example, perforations could be provided along a circumference of the housing 16, a material could be employed in select portions having reduced structural integrity or characteristics, or some latching/unlatching structure could be provided that is configured for failure upon an impact. Failure zone could be located in the gauge base 14 instead of the tower assembly 16, so that the tower assembly 16 breaks away keeping part of the base intact with the shielding. Examples of failure scenarios include, when the gauge 10 is on site, and a vehicle or compactor runs over it or if damage is done by other equipment, then the source 24 and shielding 20, 26 and 30 would break away from the base 14 and not separate from each other. That is, the shielding breaks away with the source 24 staying intact, thus shielding the source 24 even upon damage to the gauge 10. By ruggedizing the tower/bioshield assembly in a configuration that, in the event of an accident, will break away from the base 14 and other portions of the gauge 10 with the tower/bioshield assembly intact to keep the source 24 shielded, safety and integrity of containment is assured. This feature has merit with regard to regulations and represents a unique design feature along with the shielding in the source rod tip to eliminate, in some embodiments, a moveable shutter or shield. FIG. 5 illustrates an actuator assembly 36 that is configured for translating source rod 22 so as to move the source 24 from the shielded to other positions such as the measurement position, the background and the standard position. The actuator assembly 36 may include an electronic access module 40 that must be activated in order to advance the actuator assembly 36 from the locked position to the unlocked position. The electronic access module 40 may be any appropriately configured module, such as, for example, an RFID reader that communicates with an RFID card, FOB, dongle, or the like of an authorized operator. The RFID key could be worn and use low power Bluetooth. The Bluetooth link in the user's phone could act as an automatic authorized key. In this manner, the operator must have one of the RFID card, FOB, dongle, and the like to communicate with the RFID reader in order to unlock the actuator assembly 36. Alternatively, an RFID ring to be worn by users, or a medallion, otherwise worn or carried, may unlock the source electronically. Retracting the source to the safe position may not require a key to allow a safe configuration of the source to be implemented whether RFID access is satisfied or not. In other words, retraction back to the shielded position of source 24 does not require authentication with one or more security features disclosed herein. In this manner, in the instance where a source 24 is extended into the measuring position but later the operator does not know or does not have authentication access, the source 24 can still be retracted into the shielded position but cannot then be extended into the measuring position. A keypad is provided in some embodiments to work in conjunction with or in lieu of an RFID key. A controller executing software executable instructions may be provided. To activate the actuator assembly 36, the trigger 42 is squeezed while gripping handle 46. This causes an arcuate profile of extension 48 of trigger 42 to impart translation of index piston 44 in the A direction arrow. A hook 50 of the index piston 44 is now spaced-apart from an index strip 52 defined on guide bar 15. With the hook 50 spaced-apart from index strip 52, the source rod 22 can be translated downwardly in the B direction arrow. A desired measurement depth is selected by releasing the handle 46 when hook 50 is proximal a corresponding index strip 52 opening. Further downward translation or return of the source rod 22 to the uppermost position may be accomplished by squeezing trigger 42, and placing the source rod 22 in a desired position. It is contemplated that although FIG. 5 shows electronic locks and authentication codes, that a mixture of mechanical locks and assemblies could be incorporated to keep unauthorized persons from exposing the source. For instance, a magnetic latch with a magnet placed at a certain spot may authenticate and allow a pin to be removed and the trigger actuated. Likewise, an allen screw (key) or latch uncovered using a keyed (key) window is also effective in unauthorized exposure of the source. Thus a double key approach. Alternatively, in the embodiment in which an electromechanical lock assembly 60 is utilized, a solenoid 62 pushes a plunger 64 into a lock pin 66 that extends into engagement with the index piston 44. A biasing spring 68 is provided for biasing the lock pin 66 into a biased, locked state. A bushing 70 may be provided for guiding the lock pin 66. The solenoid 62 is configured for being in communication with the electronic access module 40. Still, in other embodiments, a mechanical key, lock pad, and the like may be employed for actuating the spring engaged locking pin 66 Upon communication and authentication with electronic access module 40, the solenoid 62 translates the plunger 64 and lock pin 66 upwards away from the index piston 44, the trigger 42 is squeezed, and the index piston translates in the B direction arrow as illustrated in FIG. 7 such that the hook 50 is not within an index strip 52 opening and the source rod 22 can be translated along the B direction arrow by pushing downward on handle 46. Returning the source 24 to the stored/background position automatically locks the handle 46 in one or more embodiments. The pin 66 can retract back to the initial position or can be left into the unlatched position. FIG. 6 illustrates the index piston 44 translated in the direction of arrow A where the translated position is shown in solid lines and the un-translated position is shown in broken lines. If the operator picks up the gauge 10 by grabbing onto handle 46, the handle 46 translates upwardly with the source 24 so that the gauge 10 returns to the shielded position. In one or more embodiments, an orientation detector may be utilized and in communication with the electronic access module 40 and will only allow unlocking of the actuator assembly 36 when the orientation detector 96 detects that the gauge 10 is in a horizontal, generally bottom facing downward position. In this manner, the gauge 10 cannot be turned on its side and the source 24 extended, exposing the operator to radiation. This will eliminate the ability for a user to tilt the gauge sideways to observe the source entering the hole in the ground. Other methods of lining up the source with the hole are possible, such as using a locating mat or template, pad or plate that locates the gauge directly over and aligning the source with the hole. For example, a plastic box larger than the base of the gauge is positioned over the testing hole that is 0.75 in. in diameter. A short plug of slightly smaller diameter is placed in the hole, with a “cross” frame that aligns the plastic gauge locater with the hole. Once the locater is aligned with the hole, the plug and cross are removed. Then the gauge can be placed interior to the locator with its source aligned directly over the hole. The source can then be lowered perfectly in the hole without having to tilt the gauge to the side to see the alignment. A thin pad, template, or plate could also suffice as a template. A braded holed eyelet slightly greater in diameter than 0.75 in could locate the source hole, and the thin template has an outline of the gauge. The method here would be to place the template on the predrilled hole, and flatten the thin template to the soil. Then the gauge would be placed on its outline ensuring that the source was aligned. Still in other embodiments such as in FIG. 6, an electromechanical or electromagnetic lock assembly 41 may be included and positioned about any part of the actuator assembly 36. In one embodiment illustrated, the electromagnetic lock assembly 41 is positioned about an index piston 44 and in communication with the electronic access module 40. The electromagnetic lock assembly 41 produces an electromagnetic force against index piston 44 and maintains the index piston 44 into place until an authorized operator communicates with the electronic access module 40. In this manner, the electromagnetic lock assembly 41 prevents unauthorized use of the gauge 10 by limiting operation of the actuator assembly 36 and maintaining the source 24 in the shielded position within the source housing 16. FIG. 8 and FIG. 9 illustrate placement and use of the gauge 10. A hole 80 is bored into a surface, such as a soil or sub-base surface or surface to which asphalt or concrete top layer is about to be constructed. The operator uses a template to mark or locate the position of the gauge relative to the hole 80 and then places the gauge 10 such that the source rod 22 is directly above the hole. A looking glass, visual port or similar may be provided on a portion of the gauge 10 to additionally help with this alignment or location of source in the hole. Once the gauge 10 is correctly in place, the source rod 22 is translated into the measuring position by actuating the actuator 36 as discussed with reference to FIG. 5, FIG. 6, and FIG. 7. Source rod 22 is translated into the “background” position (FIG. 8) where the “shielded” tip of the source rod is only extend out of the base 14. In this position the shielding material placed on the base 14 shields the gamma radiation reaching the detector. The gamma-radiation that is counted is correlated to the natural gamma-radiation emitted by the soil, asphalt, or concrete. A measurement of the natural gamma-radiation is required when using low activity gamma-radiation sources. FIG. 9 shows the source rod in a ‘measurement’ position. Measurements are then received by the detector 12 and any other characteristics that should be monitored such as location, time, authentication, and orientation detector. The measurement process may occur over a defined period of time in order to get a significant number of measurement counts. One or more methods are illustrated in the flow chart in FIG. 10 and generally designated 100. The one or more methods 100 include forming a hole in a ground or road surface 102, positioning the gauge such that the source and hole are aligned 104, this may incorporate a locating pad or device, authenticating user access by one or more authentication methods 106, translating the source into a measuring position 108, and recording, analyzing and displaying measurements from the detector 110. The authentication step may be any of the security methods disclosed herein, such as, for example, use of the access control module 40 described herein. In one or more embodiments, the method 100 may include: 1) Prepare the test site. Level soil with scraper plate and drill or punch hole at least 2 inches deep 2) Place gauge on the site with respect to hole using gauge positioning template, locating pad or plate 3) Keep source rod in SAFE (shielded) position 4) Take a standard count by pressing STD key 5) Follow instructions on display message-1: “count accepted. Place the source rod to BGD position and press ENTER key” message-2: “count not accepted: retake count” message-3: “count not accepted: Move source rod to SAFE position and retake count” <pressing ESC key takes to the ready screen.> 6) For message-1 (count is accepted), move source rod to BGD position 7) Press ENTER key 8) Now gauge will check whether the source rod is in BGD position and take a BGD count. If source rod is not in BGD position, gauge displays message-1: “Place the source rod to BGD position and press ENTER key” 9) Now gauge will check whether the new standard count follows the decay trend and display message-1: “New standard count accepted” message-2: “New standard count x % different than the expected count. Do you want to accept the new count? Yes/No” 10) If count is acceptable, the gauge a) determines the ‘Active Standard Count’ b) assigns filenames and archives SAFE and BGD spectra c) displays filenames of SAFE and BGD spectra d) store the ‘Active Background Count’ Normal operations include taking a daily standard count by drilling a hole at least 2 inches deep into a surface. In the step of forming a hole, the hole is drilled into the test material at least 1 inch deeper than the desired measurement depth. The gauge is placed over the test hole (using the template), with the source rod generally vertically aligned over the test hole. The source rod is extended into the test hole for measurement of the host material. According to FIG. 10, access to the source 24 is restricted by safety features and modules. The source rod 22 is contained within the source rod housing 21 using security fasteners, which the typical user would not have access to. The source rod 22 may be constructed primarily of stainless steel. The end cap 26 may be constructed of stainless steel with a tungsten insert or gamma-ray absorbing insert such as lead. The source 24 is placed into the end cap 26 and the end cap 26 is permanently attached to the source rod 22 by welding for example. The interrogator system 94 may then communicate with the accelerometer 28 to determine that an impact event that could lead to failure has or has not occurred. In one or more embodiments, in the option of using a regular sliding bioshield material, an electronic alarm system to interrogate the shield integrity is desired. This alarm system could be a mechanical switch, magnetic sensor, optical, electronic, proximity, radiation leak detector as example. The interrogator system 94 integrated into the carrying case or base 14 could also be deployed. The interrogator system 94 could interrogate the shield integrity by radiation signature, acoustic signature, electric and magnetic field sensors, proximity sensors. For example, a simple capacitive sensor can detect if the source rod 22 is in its exact position for storage. If the source 24 is removed or has mechanical problems, that would translate into a different location that could be detected by the electronic circuitry. This type of system would be used for a backscatter gauge, where the bottom shield 30 is significantly shortened or eliminated. Diagnostics capabilities in various embodiments are included, for example to monitor the condition of the source, even when un-attended. Control/monitoring module 202 may be provided for addressing these diagnostic capabilities. A gauge controller may execute diagnostic routines in this case. If the source level becomes too large or too small, authorities could be notified. An alarm could be provided or transmitted by wireless communication, wired communication, audible report, or visual indication. Other diagnostic devices may include monitors for charging, voltage, source monitoring, count monitoring, source rod position monitoring, and temperature monitoring. A gauge position sensor may require a condition that precludes extending the source rod into air. The orientation detector 96 may be provided, and may be in communication or integrated with a locking device to assure an upright position of the gauge before permitting the source to be deployed. Diagnostic alarms could be transmitted by WiFi, Bluetooth, or cellular link. The accelerometer 28 may be provided to record shock/stress data. Such data can be used to monitor gauge handling conditions, particularly for example to confirm mishandling or characterize handling conditions in the event of damage to the detector crystal (for example, for warranty purposes). Other capabilities and features include: an on-board GPS device 98 for tracking of the gauge and an electronic lockout feature if the gauge is not returned to authorized personnel or facilities for safety inspection and gauge calibration occasionally, for example at predetermined intervals. A tethered source and source rod would require breaking the tether and activating an alarm. Such alarm could be audible or a communication alarm and could be triggered by voltage and current measurements of the tethered rod. In at least one embodiment, a source view port is provided to help overcome difficulties that sometimes occur in getting the source rod to slide into the test hole. In some cases, a user considers exposing the source rod to assure alignment and insertion into the test hole. An optical view port may be provided to permit the user to visually confirm source rod alignment with the test hole. A leaded glass or lens could be used to cut down on radiation exposure from the visual port. Natural light entry is permitted in some examples. An LED or other light emitting device can be included to illuminate the area under the gauge and around the test hole. A small camera is included in some embodiments to facilitate viewing of the source and test hole. The display could be on the gauge screen, or wirelessly linked to an alternative display such as a cell phone. Alternatively, a template may be used to determine proper placement of the gauge 10. A moisture measurement system 90 is provided in some embodiments. In particular embodiments, a non-nuclear moisture sensor is attached external to the gauge 10, with an attaching mechanism in the left or right side of the gauge base. Integrated moisture sensors are also considered. Cables for the non-nuclear sensor exit and extend from the interior of the gauge through a port in the gauge cover. The non nuclear sensor eliminates the need for a neutron emitting source, however a small neutron source may be permitted. In this matter, replacing the neutron with an electromagnetic moisture or non nuclear moisture system reduces the radioisotope configuration greatly. Examples of non nuclear moisture systems include capacitance, microwave, reflectance measurements, monopole, down hole, surface, chemical and thermal. Moisture data is transferred to the gauge controller by wire or wirelessly. Super sensitive detectors such as scintillation detectors are very efficient at reducing the gamma ray sources while keeping the standard deviation well above acceptable levels. As such, the counting statistics of these systems is substantially the same as conventional gauges with 8mCi Cs-137 gamma sources and gas Geiger Mueller tubes. In one example, a non-nuclear moisture sensor is attached externally to the gauge, with an attaching mechanism in the left side of the gauge base. This system could also be integrated into or with the gauge 10 such as directly on the bottom. Exemplary non-nuclear moisture sensors include a fringing field capacitance device on the bottom surface, a monopole, a dipole, microwave resonator, integrated into the drill rod, or based on radar principles such as GPR, impulse radar, FMCW radar. Sensors could be ground coupled or non-contacting. Cables for Non-nuclear sensor leave the interior of the gauge through ports on the gauge outer shell. In one or more embodiments, the source 24 is in a doubly encapsulated source capsule, which may be placed with a spring and spacer into a third capsule, which is screwed or pressed onto the Stainless Steel source rod, and then welded into place. The NRC requires that the source 24 in hand not cause greater exposure than a threshold. The third encapsulation permits higher activity to fall within regulatory standards. Previously, double-encapsulated sources were transported then further encapsulated when assembled with a source rod. According to embodiments described herein, a triple-encapsulated source is assembled permanently sealed, and transported. According to one or more embodiments, one or more aspects that may have already been disclosed such as a GPS tracking system, automatic locking system, or even CO-60 which has a 5.26 year half life (Cs-137 has a 30 year half life) may be employed. 60 uCi will be reduced to 30 uCi after 5 years and still have 30 times more than the exempt quantity; whereas cesium would take 30 to 60 years and 80 uCi will be reduced to 40 uCi after 30 years and still have 4 times more than the exempt quantity. The one or more embodiments herein may lead to a few manufacturing processes. Examples might be robotic welding of the source rods, source storage methods and in house procedures from shipping in to assembly, monitoring storage areas and areas where the source is handled etc. Regarding storage of multiple gauges and concerns there toward total activity and exposure, a storage alarm could be included whereby radiation background is measured. If it gets above some set point, an alarm or notification is executed. The alarm could be the gauges as well since they have detectors in them and communication modules as an option. A gauge could wake up and do a count, even when in a shipping container in storage. An extra detector and electronics system could be incorporated into the shipping container for constant monitoring. In one or more embodiments, the source 24 may be provided with a triple encapsulation, or quadruple encapsulation using the source rod tip as the final welded assembly. Here, the source vendor would sell the complete source rod as an entire length, which may be 14 inches long. Then the dose would be from the source rod tip, and would be much less, but at a better rate for instrument precision and background correction. At that point, the source 24 could be much bigger because of the added protection of a third or fourth layer of steel. The one or more embodiments may be accomplished as a second or even first encapsulation. Alternatively, this could be replicated at the second or even first encapsulation step with proper design and corporation. Hence, the final encapsulation could take on the form being defined as a first, second or third encapsulation. The length or dimensions of the encapsulation may not be important, just the final dose rate by definition. By triple encapsulation of the proper shielding materials, and forming a window for a highly directional radiation source, a greater amount of energetic photons from a larger source could be directed to the detector while satisfying any regulatory objectives. The overall radiation profile would be reduced, yet performance increased. A system is illustrated in the system diagram of FIG. 11 and generally designated 200. The system 200 is embodied on the gauge 10 and includes a control module 202 that is configured to communicate with one or more modules and aspects disclosed herein. The system 200 may be in communication with the detector 12 and monitors and stores one or more measurements found thereon onto a memory 84. Memory 84 may be ROM, RAM, or any other appropriately configured memory. A communication module 86 may also be provided and is configured for wired or wireless communication with a computer, server, or the like. The control module 202 may be in communication with the accelerometer 28. In this manner, when the control module 202 and accelerometer 28 detect an acceleration of the gauge 10 above a predetermined threshold, the control module 202 may determine that an event has occurred that could compromise the integrity of the source 24. The control module 202 may then direct the detector system 94 to interrogate the source 24 and associated shielding to determine if a compromise of the source or shielding has occurred. The system 200 may further include a moisture sensor 90 to eliminate the need for a neutron source or may be used in combination with the neutron source or gamma source 24 in order to determine additional construction property characteristics. In this manner, both neutron related and moisture related characteristics could be determined. The system 200 may further include an orientation detector 96. The orientation detector 96 may be any appropriately configured detector and may be in communication with the authentication module 40 and the electromagnetic lock 60. In this manner, when the control module 202 determines that the orientation detector 96 does not detect a generally horizontal position of gauge 10, the control module 202 can direct the electromechanical lock 60 to lock the source rod 22 such that the source 24 remains in the stored position. The control module 202 may be in communication with the GPS capability module 98 and may be configured to transmit location, time, and other desired characteristics. Additionally, a keypad 82 may be provided for communication with the authentication module 40 and any other device to which an input may be desired. While the embodiments have been described in connection with the preferred embodiments of the various figures, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiment for performing the same function without deviating therefrom. Therefore, the disclosed embodiments should not be limited to any single embodiment, but rather should be construed in breadth and scope in accordance with the appended claims.
042108179	claims	1. An apparatus for practicing biplane radiography comprising first and second X-ray emitters arranged to direct x-rays through a common object along intersecting planes and first and second film changers for sequentially presenting film for exposure by x-rays generated by said first and second x-ray emitters respectively, the improvement for eliminating cross-fogging comprising: first and second shielding means associated with the first and second film changers respectively, each said shielding means having radiolucent and radiopaque portions alternately disposed in front of the associated film changer to allow or block passage of x-rays to the film presented for exposure, respectively; and means for synchronizing the shield means to dispose the radiopaque portion of one shielding means in front of the film presented for exposure by its associated film changer when the radiolucent portion of the other shielding means is disposed in front of the film presented for exposure by its associated film changer. 2. The apparatus of claim 1 wherein at least one of said shielding means comprises a flexible endless belt having alternating radiolucent and radiopaque portions with said endless belt forming a loop which surrounds said film changer. 3. The apparatus of claim 1 wherein at least one of said shielding means comprises a planar member having adjacent radiolucent and radiopaque portions and mounted for movement in a plane parallel to the plane of the film presented for exposure. 4. The apparatus of claim 3 wherein said shielding means comprises a disc mounted for rotation in said plane parallel to the plane of the film presented for exposure and having alternating sectors of radiolucent and radiopaque material. 5. The apparatus of claim 3 wherein said shielding means comprises a planar member having one radiopaque and one translucent section mounted for reciprocal movement.
	summary
	description	The present invention relates to a novel temperature detecting device forming a multipoint rod thermometer designed to detect temperatures at various points. The main application of the invention is to the detection of the occurrence of boiling crises by means of a device for electrically simulating nuclear fuel rods intended to be assembled into assemblies using spacer grids and intended to be used in what are referred to as power reactors and more particularly pressurized water reactors (PWRs). Implementation of such a device allows nuclear fuel rods to be qualified thermo-hydraulically, and in particular allows the occurrence of boiling crises in the liquid in which they are intended to be submerged to be detected under conditions that are representative of an actual nuclear reactor. The occurrence and location of a boiling crisis must be detected in electrical simulating devices with response times that would allow safety systems to be activated. Generally, the invention aims to detect, using one and the same device, temperatures at various points distributed in a plurality of axial and azimuthal positions and in particular distributed with a high spatial density. Although described with reference to the main application, the temperature detecting device according to the invention may be used to detect various temperatures or temperature gradients at various points on a given wall to be monitored, the temperatures at each point being detected by radiated heat. To qualify a nuclear fuel rod assembly intended to be used in a pressurized water nuclear reactor (PWR), it is necessary to carry out boiling crisis tests. More precisely, it is necessary to be able to detect the occurrence and location of boiling crises. Specifically, a boiling crisis may generally be defined as a substantial change in wall temperature for a small variation in thermo-hydraulic control parameters. A boiling crisis manifests itself by an abrupt degradation in the heat exchange between a heated wall and the coolant that surrounds it, i.e. an abrupt increase in wall temperature. Thus, in a PWR reactor, the occurrence of this effect could cause the cladding of a nuclear fuel rod to rupture. In other words, nuclear fuel rod assemblies must be qualified with respect to boiling crises in order to allow operating tolerances to be evaluated for the operating conditions encountered during nominal operation, incidents or control transients, and the risk of damaging rod claddings, which are the first containment barrier of the fuel, to be limited. This qualification consists in defining experimentally the occurrence and location of a boiling crisis by means of devices for electrically simulating nuclear fuel rods generating high heat flux densities. Implementation of a simulating device consists in submerging the device in an almost uninterrupted flow of liquid and slowly varying a single thermo-hydraulic parameter, while the other parameters are adjusted to preset constant values, until a boiling crisis is obtained. As regards devices used to simulate electrically nuclear fuel rods generating high heat flux densities, most of those used are what are referred to as direct heating devices because the cladding of the device, which makes contact with the heated water, also constitutes the resistive heating element. In other words, the cladding is directly heated. The Applicant has also proposed, in patent application FR 11 54336, filed 18 May 2011, an electrical simulating device employing indirect heating, which especially allows nuclear fuel assemblies intended to be submerged in an electrically conductive coolant to be qualified, such as is the case for the generation IV fast breeder reactors (FBRs) that used sodium as a coolant (Na-FBRs), which will require high heat flux density sodium boiling tests to be carried out. Whatever the type of electrical simulating device, the detection of the occurrence of a boiling crisis and its location requires a high spatial measurement density and, for safety reasons, very short response times, access constraints being very tight because the devices are made up of tubes of small diameter. In particular, a high spatial measurement density is required because of the high thermal flux density that, in general, has a nonuniform axial profile, due to neutron transport. The grids are of shape, size and axial positions identical to those of a assembly in a reactor. Up to now in practice, in simulating devices employing direct heating, thermocouples cladded with steel or another analogous material are welded directly to the heated cladding at points to be monitored, i.e. in zones where boiling crises are expected. This technique has many drawbacks which may be enumerated as follows: it substantially limits the number of measurement points due to the very limited space available for thermocouples in the device; it may cause local disruption of the heating current in the cladding and therefore of the heat flux density and thus of the boiling effects observed; it is relatively expensive in terms of investment and in terms of the man-hours required to form the measurement points, more particularly in the case of a large number of tests; and with this technique it is impossible to recover the measurement instrumentation and the heated claddings. In the simulating device employing indirect heating of the aforementioned patent application FR 11 54336, the Applicant proposes to insert each of a plurality of thermocouples into a groove produced on the outside periphery of an unheated cladding making direct contact with the liquid to be heated, with the attendant advantage of allowing the thermocouples to be positioned with a high precision. Nonetheless, the number of measurement points remains limited, the cost of forming the measurement points remains high and it is again not possible with this technique to recover the measurement instrumentation and the instrumented claddings. Moreover temperature detecting devices, commonly called multipoint rod thermometers/pyrometers, that comprise elements sensitive to temperature, such as resistance thermometers, thermoelectric couples or thermistors, housed in a protective cladding, are known. These rod thermometers have the advantage of being able to be implanted in situ, of not physically impacting the one or more walls of the object on which temperature is detected and of being recoverable after the temperature measurements. This being so, currently available rod thermometers do not allow a very high spatial measurement density to be obtained, are relatively expensive and cannot actually be implanted in zones in which the available space, or in other words access, is very restricted. There is therefore a need to improve existing temperature detecting devices and techniques, especially with a view to obtaining a higher spatial measurement density, even in zones where available access space is very restricted, with a view to decreasing the cost of instrumentation for measuring walls to be monitored, and with a view to making it possible to recover and reuse all the components of the measurement instrumentation and the monitored walls, such as the heated or unheated claddings of devices for electrically simulating nuclear fuel rods. The general aim of the invention is therefore to provide a novel temperature detecting device that meets this need at least partially. One particular aim of the invention is to provide a temperature detecting device that is able to be used in a device for electrically simulating a nuclear fuel rod. To do this, the subject of the invention, according to one of its aspects, is a device for detecting temperature, forming a rod thermometer, comprising: a plurality of elements sensitive to temperature; and a protective cladding of longitudinal axis X in which the sensitive elements are partially housed, characterized in that the cladding is made of a metal constituting one of the two metals of a thermocouple, and in that the sensitive elements consist in a plurality of wires made of a metal different from that of the cladding and constituting the other of the two metals of a thermocouple, one of the ends of each of the wires being welded to the interior of the cladding so as to form a measurement junction of a given thermocouple, the welded ends of the wires being distributed in a plurality of axial and azimuthal positions relative to the axis X in the interior of the cladding, each of the wires exiting from the cladding via at least one of its ends. In other words, the invention consists in giving a cladding of a rod thermometer, which in the prior art only had the function of protecting the sensitive elements, another function, namely the function of a metal common to a plurality of thermocouples, the other metal of each of the thermocouples being that of a wire welded directly to the cladding, the wires being distributed in a plurality of axial and azimuthal positions. In yet other words, according to the invention, the metal of the cladding is used as one of the two metals of a thermocouple and as a metal common to all the thermocouples; a wall temperature is detected by radiated heat at a point set by a single wire made of the other metal of the thermocouple. By virtue of the invention, it is possible to detect temperatures in as many as several hundred zones per object to be monitored, such an object possibly being an electrical simulator of nuclear fuel rods, while keeping the cost of the measurement instrumentation relatively low. The rod thermometer according to the invention is, moreover, independent of the object to be monitored, it and the objects to be monitored, such objects possibly being the heated claddings of electrical simulating devices, may therefore be reused many times. In other words, the rod thermometer according to the invention has many advantages relative to the detection techniques of the prior art: it increases the number of temperature detection points, typically to several per linear centimeter; the thermocouples do not disrupt the heat flux density locally; the cost of the measurement instrumentation is substantially decreased; the rod thermometer and objects to be monitored, such objects possibly being heated claddings, are easy to recover; and the rod thermometer according to the invention may be adapted to detect temperatures under a wide range of environmental conditions, because of the very high spatial density of the detection points. Preferably, the metal of the cladding is a type-K material. Again preferably, the metal of the wires is a type-K material. Thus, according to one preferred variant embodiment, the cladding is either made of chromel or of a nickel/chromium alloy such as Inconel® 600, and the wires are made of alumel. Such type-K thermocouples have the advantage of being able to measure a wide range of temperatures and of being inexpensive. According to one advantageous feature, the wires are covered with an electrical insulator apart from their junction ends. Thus, each thermocouple is electrically insulated from the others and from the cladding. According to one preferred variant embodiment, the alumel wires are covered with an alumina deposit. Preferably, the thickness of the cladding is smaller than or equal to 0.1 mm. Again preferably, the outside diameter of the wires is smaller than or equal to 0.1 mm. With these dimensions, the thermal inertia of a measurement point at the junction between a wire and the cladding is relatively small, thereby ensuring a relatively short response time. It is thus possible to detect the occurrence of a boiling crisis very rapidly. Typically, in an electrical simulation device employing direct heating, for a heated cladding temperature of below 750° C., and for an increase in the temperature of the latter of about 1000° C. per second, the inventors believe that it is possible, by virtue of the rod thermometer according to the invention, to detect deviations in temperature above the required detection threshold, typically more than 10° C., in a time shorter than 100 ms. A boiling crisis in a device for electrically simulating a nuclear fuel rod is thus detected as soon as the temperature variation exceeds the set threshold, which is at least equal to 10° C. According to one advantageous feature, the rod thermometer comprises at least one adapter-tube made from the same metal as the cladding and of larger outside diameter than that of the cladding, the adapter-tube being brazed around the cladding at the end where the metal wires exit. This makes it easier to fit the rod thermometer in a heated cladding. Another subject of the invention, according to another of its aspects, is a process for manufacturing the rod thermometer described above, comprising the following steps: cutting longitudinally along two opposite generatrices a tube made of a metal constituting one of the two metals of a thermocouple, so as to form two half tubes; welding one end of each of the plurality of wires made of a metal constituting one of the two metals of a thermocouple to the interior of at least one half tube, the ends of the welded wires being distributed in a plurality of axial and azimuthal positions; and reconstituting the metal tube forming the cladding by welding along each generatrix while leaving the plurality of metal wires to exit via at least one of its ends. Such a manufacturing process is simple to implement especially because the interior of the half tubes is easy to access. Each metal wire may also easily be unwound from conventional reels holding about one hundred meters of wire. Preferably, the welding of one of the ends of the wires to at least one half tube is achieved by arc welding. Again preferably, the reconstituting welding is spot welding. These well-characterized welding techniques allow very precise measurement junctions to be produced. The invention also relates, according to another aspect, to a method for installing the temperature detecting device described above in a device for simulating electrically a nuclear fuel rod comprising at least one tube made of an electrically conductive material, referred to as the heated tube, that is intended to heat a liquid, in order to detect the occurrence of a boiling crisis in the liquid, in which, the cladding forming the common metal of the thermocouples is arranged in the interior of the electrical simulating device and at a distance from the heated tube, the space between the cladding and the heated tube is filled with a pressurized insulating gas and the space filled with pressurized insulating gas is sealed. According to one advantageous variant embodiment, in order to avoid the risk of short circuits, the arrangement at distance is achieved by means of spacers made of an electrically insulating material, such as ceramic spacers, that are fastened to the exterior of the cladding housing the welded wires and fitted so that there is play with the interior of the heated tube, in zones devoid of wires. The play between the spacers and the interior of the tube corresponds to a fitting tolerance increased by an allowance for thermal expansion. According to one advantageous variant embodiment, to decrease the response time of the temperature detection, the interior of the heated tube and/or the exterior of the cladding is treated, before the arrangement, so as to provide it (them) with a thermal emissivity at least equal to 0.8. The treatment may advantageously consist either of controlled oxidation of the tube, preferably by heating in an oxidizing atmosphere, or of coating with a material having a high thermal emissivity, such as a black paint. Lastly, one subject of the invention is the use of a rod thermometer according to the invention as described above, installed using the method described above, to detect the occurrence of a boiling crisis. It will be noted here that electrical simulating devices of the direct heating type (FIGS. 1 and 3) and of the indirect heating type, as described and claimed in patent application FR 1 154 336, (FIG. 2) must allow the occurrence of a boiling crisis, defined as a substantial change in wall temperature for a small variation in thermo-hydraulic control parameters, to be detected. It will also be noted that in all of FIGS. 1 to 3, the references Lt, Ln and Lc and l respectively designate: Lt: overall length of the electrical simulating device; Ln: length of the device submerged in the liquid; Lc: heated length of the device; and l: overall length of the rod thermometer. It should be noted that in the design of direct heating electrical simulating devices (FIGS. 1 and 3) provision is made for an electrical connection to be submerged in the liquid to be heated (Liq), whereas an indirect heating electrical simulating device (FIG. 2) is designed so that there is no submerged electrical connection, this being advantageous because there is then no need to provide for sophisticated electrical insulation from the exterior environment. It will also be noted that to carry out boiling crisis tests, an electrical simulating device in which a rod thermometer according to the invention is installed is arranged within a assembly (not shown) of a plurality of identical devices with spacer grids inside a tank (not shown) containing the liquid to be heated, the two electrical connections protruding from the tank while being insulated therefrom by suitable means, and the tubular resistor is supplied with DC current. For pressurized water reactors, the liquid to be heated is water. For other applications, the liquid to be heated may be different. Typically for sodium-cooled fast breeder reactors (Na-FBR), the liquid to be heated is sodium. For these boiling crisis tests the following parameters are fixed for each electrical simulating device: heated length Lc, typically from 1 to 4.3 meters; the axial heat flux density profile per rod, typically from 0.2 to 3.5 MW/m2; exterior cladding outside diameter typically from 8.5 to 10.7 mm; and total electrical supply, typically 250 V with a maximum local gradient equal to 100 V/m. Likewise, for these tests, the following parameters are fixed for the assembly together of a plurality of electrical simulating devices: the type and the positions of the spacer grids, defining the type and the pitch of the cells of an assembly; and the number of devices per assembly, which must be small, typically from 19 to 37. The internal operating conditions of the electrical simulating device as follows: internal operating temperature in the steady-state: 450° C.; internal operating temperature during a boiling crisis: 800° C.; and internal neutral-gas pressure: 180 bars. For the sake of clarity, analogous elements of direct and indirect heating devices have been given the same references. FIG. 1 shows an electrical simulating device that is conventionally referred to as a direct heating device. The device 1 consists of a resistor 2 taking the form of a tube that also serves as an external cladding. In other words, the tubular cladding 2 also plays the role of an electrical resistor, i.e. the part supplied with current in order to heat the liquid in which the device is submerged. The interior 20 of the tubular resistor/cladding 2 is filled with pressurized nitrogen. Two electrical connections 30, 31 are each inserted into one of the ends of the resistor/cladding 2. One of the connections 30 is that which supplies the current: it is drilled through its center in order to house the rod thermometer 4 according to the invention of longitudinal axis X, which extends longitudinally along the axis of the device in the interior of the heated cladding 2 through the space occupied by the pressurized insulating gas 20, as will be detailed below. In this end, the seal tightness of the heated cladding 2 to the pressurized nitrogen in the interior 20 thereof is ensured both by the connection 30 itself and by an end plug 5 made of an electrically insulating material. The other 31 of the connections is that through which the current leaves: it is unapertured and therefore also serves as a sealing plug. FIG. 2 shows an indirect heating electrical simulating device 1 such as described and claimed in patent application FR 1 154 336. It essentially consists of: a tubular resistor 2 of the same type as that of the direct heating device 1 shown in FIG. 1, in order to obtain a high heat flux density having an axial profile dependent only on the variation in the thickness of the resistor, and a uniform, i.e. azimuthally invariant, transverse profile; the radial dimensions of the tubular resistor are smaller in order to electrically insulate it using an added electrically insulating but thermally conductive intermediate element 6 that preferably has a very high thermal conduction coefficient; an external cladding 7 of a thermally conductive material that encases the tubular resistor 2/intermediate element 6 assembly, the outside diameter of said cladding being the fixed diameter indicated above (8.5 to 10.7 mm), i.e. that of the claddings of nuclear fuel rods intended for PWR reactors; and a rod thermometer 4 according to the invention installed in the interior of the resistor 2 in the space occupied by the pressurized insulating gas 20. Furthermore, the tubular resistor 2 is supplied with DC current via the connection 30. For applications other than the qualification of nuclear fuel, the electrical supply may be a single-phase AC supply. In the embodiment in FIG. 2 the electrically insulating and thermally conductive intermediate element is a column of ceramic pellets 6 drilled through their center, stacked one on top of the other and inserted around the tubular resistor 2 over its entire length and around a portion of the electrical connections 30, 31. In the electrical simulating devices 1 described above, given the fixed internal operating conditions and parameters, during a boiling crisis in which the exchange coefficient drops to a very low value, the temperature of the heated element wall 2 in FIG. 1 and of the external cladding wall 7 in FIG. 2 increases by 1750 K/s with an uncertainty of 300 K. The electrical power supply of the heated element 2 must be cut with a characteristic fall time shorter than 170 ms, thereby, on account of the properties of the power supply control unit, leaving about 100 ms for the characteristic detection time. Up to now, in the prior art, the temperature detecting devices used to detect boiling crises in electrical simulating devices consisted of thermocouples, for example eight K-type thermocouples made of inconel 600, each arranged making contact with the heated element 2 in FIG. 1 or the exterior cladding 7 in FIG. 2 in various axial and azimuthal positions in locations specified with a tolerance of +/−2 mm. In a direct heating device 1 analogous to that shown in FIG. 1, the thermocouples were welded directly to the heated cladding 2. In an indirect heating device 1 analogous to that described in patent application FR 1 154 336 and shown in FIG. 2, provision was made to insert the thermocouples into grooves produced in the exterior of the external cladding 7. The locations specified for the arrangement with direct contact of the thermocouples according to the prior art corresponded to zones in which a boiling crisis was expected to occur. With such a detection method according to the prior art, the number of temperature detection points was thus limited, typically to about ten per device 1, essentially because of the relatively high cost in terms of investment and in terms of the man-hours required for installation. Furthermore, once the tests had been carried out, on the one hand the actual thermocouples, and on the other hand the heated element 2 in FIG. 1 or the external cladding 7 in FIG. 2, were rendered unusable. To alleviate these drawbacks, the inventors of the present invention had the idea of producing a rod thermometer 4 such as shown in FIG. 3. The rod 4 according to the invention comprises a protective cladding 40 made of a metal constituting one of the two metals of a thermocouple. A plurality of wires 4.1, 4.2, 4.3 made of a metal different from that of the cladding and constituting the other of the two metals of a thermocouple is housed in the interior of the protective cladding 40. One of the ends of each of the wires 4.1, 4.2, 4.3 is welded to the interior of the cladding so as to form a measurement junction of a given thermocouple, the welded ends of the wires being distributed in a plurality of axial and azimuthal positions relative to the axis X in the interior of the cladding, each of the wires exiting from the cladding via at least one of its ends. Thus, one end of one wire 4.1, 4.2, 4.3 is welded in each axial and azimuthal position that must be monitored for the purposes of detecting a boiling crisis. Preferably, the metal of the protective cladding 40 and that of the wires 4.1, 4.2, 4.3 form K-type thermocouples. The metal wires 4.1, 4.2, 4.3 are preferably covered with an electrically insulating coating in order to insulate them from each other and from the protective cladding 40 (apart from the junctions) As shown in FIG. 3, the protective cladding is preferably made up of two portions 40, 41, the larger-diameter top portion being brazed around the bottom portion. The top portion 41 thus forms an adapter and makes it easier to fit the connection 30. To produce the rod thermometer 4 according to the invention, it is advantageously possible to proceed in the following way: cutting longitudinally along two opposite generatrices a tube 40 made of a metal constituting one of the two metals of a thermocouple, so as to form two half tubes; welding one end of each of the plurality of wires 4.1, 4.2, 4.3 made of a metal constituting one of the two metals of a thermocouple to the interior of at least one half tube, the ends of the welded wires being distributed in a plurality of axial and azimuthal positions (FIG. 3); and joining the two half tubes to make the metal tube forming the protective cladding by welding along each generatrix while leaving the plurality of metal wires to exit via at least one of its ends. The welding of one of the ends of the wires 4.1, 4.2, 4.3 to at least one half tube is achieved by arc welding and the reconstituting welding is spot welding. Provision may be made to braze or weld a seal-tight end fitting to the bottom portion of the reconstituted metal tube 40. In order to fit the rod thermometer in the interior either of the external heated cladding 2 (direct heating device 1 in FIG. 1) or of the internal resistor 2 (indirect heating device 1 in FIG. 2), the protective cladding 40 forming the common metal of the thermocouples is arranged in the interior of and at a distance from this heated tube 2, the space between the cladding and the heated tube is filled with a pressurized insulating gas 20 and the space filled with pressurized insulating gas 20 is sealed by means of one or more electrically insulating elements 5. To create the seal level with an electrically insulating element 5, such element possibly being a ceramic shim, a metal/ceramic/metal brace may advantageously be produced on the one hand with the adapter-tube 41 and on the other hand with the tube 2. Moreover, in order to ensure the rod thermometer 4 is held mechanically in the tube 2, it is possible to form a mechanical metal/metal joint between the adapter-tube 41 and the tube 2 under the electrically insulating shim 5. To avoid the risk of short-circuits, the protective cladding 40 is equipped with spacers or shims 8 made of an electrically insulating material, such as a ceramic, in zones outside of the measurement junctions. These shims 8 fastened to the exterior of the protective cladding 40 are dimensioned in order to be fitted so that there is play with the interior of the heated tube 2. The play between the shims 8 and the interior of the tube corresponds to a fitting tolerance increased by an allowance for thermal expansion. To improve the response time of the measurement instrumentation, the emissivity of the internal face of the heated tube 2 may be increased so as to be higher than a value of 0.8. Likewise, the emissivity of the external face of the protective cladding may be increased to a value higher than 0.8. In the top portion 41 of the rod thermometer according to the invention a seal 9 may be formed between the metal wires 4.1, 4.2, 4.3 and the cladding 41 that also allows said wires to be held in position. By way of example, the dimensions and materials of complete devices 1 and of the rod thermometer 4 according to the invention are given below. Dimensions: complete device 1: Submerged length Ln: 1.2 to 4.5 m; Total length Lt: 1.5 to 4.8 m; external cladding 2 or 7: Outside diameter: 8.5 to 10.7 mm; Thickness: ˜1 mm with a value of 0.5 mm for a peak power flux equal to 3.5 MW/m2; resistor 2: Heated length Lc: 1 to 4.3 m; Outside diameter smaller by about 0.5 mm to the inside diameter of the external cladding 7; Inside diameter dependent on the electrical resistance in question; ceramic pellets 6: Thickness: about 2 mm; shims 8: Outside diameter 4.9 mm; Inside diameter: 4 mm; Height: 10 mm; rod thermometer 4 according to the invention: Overall length l: 1 to 3 m; Outside diameter: 4 mm; protective cladding 40: Thickness: 0.1 mm; metal wires 4.1, 4.2, 4.3 . . . Diameter: 0.1 mm.Materials: external cladding 7: Inconel 600 or 316 L stainless steel; resistor 2: Inconel 600 or 70/30 cupronickel; stacked pellets 6 made of boron nitride or aluminum nitride and ceramic coating 22 made of zirconia; electrical connections 30, 31: copper, nickel or molybdenum; sealing element 5: ceramic shim brazed on the one hand to the tube 2 and on the other hand to the adapter-tube 41; electrically insulating sealing elements 9: resin or silicone; shims 8: alumina or zirconia; rod thermometer 4 according to the invention: protective cladding 40: chromel or Inconel® 600; wires 4.1, 4.2, 4.3: alumel covered with alumina. With the dimensions and materials indicated for the rod thermometer 4 according to the invention, the thermal inertia of the latter is a relatively low, thereby leading to a relatively short response time. Typically, for an increase in the temperature of the cladding 2 of 1000° C./s, a set detection threshold higher than 10° C. is reached by the rod thermometer 4 in less than 100 ms for a cladding temperature 2 below 750° C. Although described exclusively with regard to a device for electrically simulating a nuclear fuel rod for carrying out boiling crisis tests, the device according to the invention described above with reference to FIGS. 2 and 3 may also be used more generally in detection of the temperature of a wall for which a high measurement density is required in the axial and azimuthal directions.
	summary
	claims	1. A system for localizing an underwater remotely controlled vehicle moving within a structure filled at least partially with water, comprising:a map of the structure, the map indicating locations of one or more landmarks defined on the structure;a pan-tilt-zoom camera, disposed in the water at a stationary position with respect to the structure;software, executing on a processor, the software iterating a loop performing the functions of:panning, tilting and zooming the camera to follow a plurality of fiducials mounted on the vehicle;collecting an image from the camera;estimating an angular velocity of the camera about a vector comprising a combination of the pan and tilt axes of the camera;predicting a future state of the system based on a current state of the system and the estimate of the angular velocity;calculating a correction to the predicted state of the system based on detecting in the collected image, the plurality of fiducials on the vehicle and one or more of the landmarks indicated on the map of the structure;applying the correction to the predicted state of the system; andusing the corrected predicted state as a previous state for a next iteration of the loop;wherein the predicted state of the system includes at least a position and an orientation of the vehicle with respect to the structure and current pan, tilt and zoom settings of the camera. 2. The system of claim 1 wherein predicting the future state of the system is further based on one or more additional terms representing the focal length of the camera. 3. The system of claim 1 wherein predicting the future state of the system produces a predicted state and a covariance of the predicted state. 4. The system of claim 3 wherein applying the corrected state to the predicted state produces a corrected state and a covariance of the corrected state. 5. The system of claim 1 wherein the estimate of the angular velocity of the camera is based on a comparison of the collected image with one or more previous images. 6. The system of claim 5 wherein estimating the angular velocity of the camera uses image registration in a homography-based method. 7. The system of claim 6 wherein the image registration is intensity-based. 8. The system of claim 1 wherein the estimate of the angular velocity of the camera is based on pan and tilt angles reported by the camera. 9. The system of claim 1 wherein detecting the one or more landmarks defined on the structure from the collected image uses the map of the structure and a previous state of the system as inputs. 10. The system of claim 1 wherein the software performs the further function of detecting the one or more landmarks defined on the structure and updating the map of the structure by updating a position of the one or more detected landmarks. 11. The system of claim 10 wherein the one or more landmarks are defined points or lines on the structure. 12. The system of claim 11 wherein the map of the structure consists of a series of intersecting planes. 13. The system of claim 12 wherein the lines represent the intersections between the planes. 14. The system of claim 1 wherein the software performs the further function of determining an initial position and initial orientation of the camera. 15. The system of claim 1 wherein the software performs the further function of determining an initial location of the vehicle. 16. The system of claim 1 wherein the software performs the further function of suspending tracking and attempting to re-acquire the vehicle when tracking of the vehicle is determined to have been lost. 17. The system of claim 4 wherein the software uses an extended Kalman filter to determine the predicted state and the covariance of the predicted state and the corrected state and the covariance of the corrected state. 18. The system of claim 1 wherein the camera is enclosed in a watertight housing. 19. The system of claim 18 wherein the housing is disposed at a fixed location relative to the structure and the vehicle. 20. The system of claim 1 wherein the detected landmarks are projected from a frame representing the structure to a frame representing an optical center of the camera. 21. The system of claim 1 wherein the one or more landmarks are detected in the image using feature detection based on geometric shape.
	abstract	A method for joint configuration of nuclear power plant fuel includes the following steps: (S1) for at least one operating unit, based on an equilibrium cycle or transition cycle reactor core design, at least one new fuel element is added to at least one operating unit; (S2) after running a combustion cycle, and on basis of the new fuel elements in step (S1), more first spent fuel elements are obtained from the at least one operating unit than are obtained from the equilibrium cycle or transition cycle reactor core design, and said first spent fuel elements are kept in reserve; (S3) for at least one new starting unit, a scheduled number of new fuel elements, as well as the first spent fuel elements obtained for reserve in step (S2), are set in the first reactor cores of at least one new starting unit.
052272680	claims	1. An X-ray mask comprising: an X-ray permeable film, having a first main surface and a second main surface opposite to said first main surface, supported by a supporting frame formed of silicon; an LSI circuit pattern and a first alignment pattern formed on the first main surface of said X-ray permeable film; and a second alignment pattern, substantially identical to said first alignment pattern, formed on the second main surface of said X-ray permeable film at a position corresponding to said first alignment pattern. coating a photosensitive material over the second main surface of an X-ray permeable film being installed on a supporting frame and having a first LSI circuit pattern and a first alignment pattern formed on the first main surface; and forming a second alignment pattern opposite to said first main surface and self-adjustingly on the second main surface of said X-ray permeable film through an exposure of said photosensitive material from the first main surface of said X-ray permeable film with the first alignment pattern, which was formed on said first main surface, used as a mask and then a development of said photosensitive material. coating a photosensitive material over the second main surface of an X-ray permeable film being installed on a supporting frame and having a first LSI circuit pattern and a first alignment pattern formed on the first main surface; forming a second LSI pattern and a second alignment pattern opposite to said first main surface and self-adjustingly on the second main surface of said X-ray permeable film through an exposure of said photosensitive material from the first main surface with the LSI circuit pattern and the first alignment pattern, which was formed on the first main surface, used as a mask and then a development of said photosensitive material; and eliminating selectively the second LSI circuit pattern formed on the second main surface of said X-ray permeable film. disposing an X-ray mask, which has an X-ray permeable film with an LSI circuit pattern and a first alignment pattern formed on a first main surface and also with a second alignment pattern formed on a second main surface opposite to said first main surface at a position corresponding to that of said first alignment pattern, close to a wafer surface with the first main surface of said X-ray permeable film facing said wafer surface; and irradiating the second main surface of said X-ray permeable film with X-rays after an alignment has been performed at least through the use of diffracted lights emitted from the second alignment pattern formed on the second main surface of said X-ray permeable film upon irradiating the second main surface of said X-ray permeable film with laser beam. 2. A fabricating method of an X-ray mask having a first main surface and a second main surface comprising the steps of: 3. A fabricating method of an X-ray mask having a first main surface and a second main surface comprising the steps of: 4. An exposure method comprising the steps of:
039393666	abstract	Radioactive energy is converted to electric energy by irradiating a converter body of semiconductor material etc. with radioactive rays to produce a number of electron-hole pairs in the converter, applying a magnetic field to the converter in a direction perpendicular to the direction of diffusion of the electron-hole pairs to separate the electrons and the holes in a direction perpendicular to the direction of diffusion of the electron-hole pairs and to the direction of application of the magnetic field and deriving the electrons and the holes from electrodes provided on the respective end faces of the converter body as electric energy.
055454275	description	EXAMPLE 1 In this example preparation takes place of a first aluminium butoxide solution by mixing under a dry nitrogen atmosphere 125 g of secondary aluminium butoxide Al(OC.sub.4 H.sub.9).sub.3 obtained from Aldrich Chemical Company with an ethanol quantity such that the ethanol:butoxide molar ratio is 8, the solution being mixed for 10 min. In another beaker, preparation takes place of a lithium hydroxide suspension by suspending 21.3 g of LiOH, H.sub.2 O in an ethanol quantity such that the ethanol:lithium hydroxide molar ratio is 5. The suspension is then added to the solution (the ethanol:aluminium alkoxide molar ratio then being 13) and vigorous stirring thereof is maintained for 30 min. during which the temperature rises to 80.degree. C. This gives a white solution. This is followed by the hydrolysis of the solution by adding deionized and decarbonated water in a quantity such that the water:aluminium butoxide molar ratio is 10 and in this way a viscous mixture is obtained, which is stirred for a further 10 min. The white, pasty mixture is then dried in an oven at 150.degree. C. for 2 h or in an autoclave at 250.degree. C. and under a pressure of 7 MPa. Thus, a fine beta lithium aluminate powder is obtained. Analysis of this powder by X-ray diffraction shows that it is indeed beta lithium aluminate. This powder undergoes cold isostatic pressing or moulding under a pressure of 200 MPa for 1 min. in order to form diameter 10 mm pellets. These pellets are then directly sintered in alumina crucibles at a temperature of 850.degree. C., under air and for 2 h with a heating speed of 3.degree. C./min., after embedding the pellets in a powder bed having the same composition in order to limit stoichiometry variations. X-ray diffraction analysis of the product obtained shows that it is gamma lithium aluminate. After sintering, there is a longitudinal shrinkage of 18%, but no dilatometric anomaly is detected during beta/gamma transformation. After sintering at 850.degree. C., the relative density is 70% and the microstructure corresponds to ultrafine particles of sizes below 0.1 .mu.m. EXAMPLE 2 The same operating procedure as in example 1 is used, but sintering is carried out at 1000.degree. C. for 2 hours. In this case the density is 92% and the grain size is 0.2 to 0.3 .mu.m. EXAMPLE 3 The same operating procedure as in example 1 is used, but sintering takes place at 1100.degree. C. for 2 hours. This leads to dense pellets with a density of 99% and a uniform microstructure with grain sizes of 2 to 3 .mu.m. EXAMPLE 4 The same operating procedure as in example 1 is used, but sintering takes place at 1150.degree. C. for 2 hours. This leads to grain sizes of 3 to 8 .mu.m. Thus, the choice of a sintering temperature from 850.degree. to 1150.degree. C. makes it possible to adapt the grain sizes of the gamma lithium aluminate and obtain the desired dimensions in the range 0.1 to 10 .mu.m, with a density which evolves between 70 and 100% of the theoretical density. EXAMPLE 5 Preparation of Li.sub.4.025 Al.sub.3.925 Si.sub.0.05 O.sub.8. In this example the operating procedure of example 1 is followed, but to the secondary aluminium butoxide solution in ethanol is added a tetraethoxysilane solution in ethanol prior to adding the lithium hydroxide suspension. The tetraethoxysilane solution is prepared in the following way. 1.46 ml of tetraethoxysilane is dissolved in an ethanol quantity such that the ethanol:silicon alkoxide molar ratio is 4, followed by the prehydrolysis of the alkoxide at a pH of approximately 2 for 1 hour. This solution is then added to the freshly prepared solution of sec aluminium butoxide in ethanol and then the operations take place as in example 1. By sintering at 1100.degree. C., this gives a relative density of 95% and the microstructure obtained corresponds to grains with a size of 0.3 .mu.m. Thus, the process according to the invention is very interesting because it makes it possible to eliminate the prior calcination stage for transforming beta lithium aluminate into gamma lithium aluminate and easily regulate the microstructure and density of the product obtained.
	claims	1. A method of refueling a pressurized water nuclear reactor having a pressure vessel; an upper removable head for sealably engaging an upper opening in the pressure vessel; a core having an axial dimension supported within the pressure vessel; a plurality of nuclear fuel assemblies supported within the core, at least two of the fuel assemblies having at least one instrumentation thimble extending axially therethrough; an upper internals assembly supported above the core and having axially extending instrumentation guide paths supported therethrough with each of the instrumentation thimbles that are configured to receive instrumentation through the upper internals assembly being aligned with one of the instrumentation guide paths; the upper internals assembly including an instrumentation grid assembly plate supported above and axially movable relative to a lower portion of the upper internals; at least two in-core instrumentation thimble assemblies respectively extending through a corresponding one of the instrumentation guide paths into a corresponding one of the instrumentation thimbles and retractable into the upper internals assembly when the instrumentation grid assembly plate is raised; each of the in-core instrumentation thimble assemblies having a signal output lead that is routed within the vicinity of the instrumentation grid plate to and through a penetration flange that fits between the removable head and the pressure vessel; and an electrical connector that connects each of the signal output leads from the at least two in-core instrumentation assemblies to an output cable that extends through the penetration flange to the exterior of the pressure vessel, the method comprising the steps of:lowering a water level in the pressure vessel below the penetration flange and the electrical connector;removing the upper removable head from the penetration flange;disconnecting the electrical connector which simultaneously disconnects each of the signal output leads associated with the at least two in-core instrumentation thimble assemblies from the penetration flange;axially raising the instrumentation grid assembly plate until the instrumentation thimble assemblies are above the core;exposing the core by removing the upper internals assembly; andrefueling the core. 2. The method of claim 1 wherein the disconnecting step simultaneously disconnects all of the instrumentation thimble assemblies from the penetration flange by disconnecting the electrical connector. 3. The method of claim 1 including the step of shielding the instrumentation thimble assemblies as the instrumentation thimble assemblies are raised out of the core. 4. The method of claim 1 including the step of sealing an open end of the electrical connector. 5. The method of claim 1 wherein the in-core instrumentation thimble assemblies are attached to the instrumentation grid assembly plate. 6. The method of claim 1 wherein the instrumentation guide paths include a telescoping sleeve that is attached to the instrumentation grid assembly plate and the raising step extends the telescoping sleeve. 7. The method of claim 1 wherein the head is removed before the water is lowered below the penetration flange and the electrical connector.
	description	Other characteristics and advantages of the invention will be seen more clearly upon reading the following examples, which are naturally given as an illustration and are not restrictive. The following examples illustrate the preparation of phosphosilicate apatites corresponding to four embodiments of the invention. In all these examples, the method according to the invention is used to prepare said phosphosilicate apatites from the following reagents: CaF2, SiO2, Ca2P2O7, CaCO3 and PuO2 with Na2CO3, GdF3 and/or Gd2O3, if required. Na0.45Ca9.1Pu0.45(PO4)5.55(SiO4)0.45F2xe2x80x83xe2x80x83III. To obtain 10 g of britholite complying with the above formula, a first mixture is first of all prepared in acetone using the following quantities of reagents: CaCO3: 2.3405 g PuO2: 1.1307 g SiO2: 0.2479 g Ca2P2O7: 6.4662 g, and Na2CO3: 0.2187 g. All the reagents, except CaF2, are mixed in acetone and dried in an oven at 100xc2x0 C. for 1 hour. They are then ground to obtain a particle size of 50 xcexcm and calcined for 1 to 2 hours at 900xc2x0 C. to break down the carbonates. After cooling, 0.7160 g of CaF2 is added, and the two powders are again mixed in acetone. After the acetone has evaporated completely in an oven at 100xc2x0 C. (around thirty minutes), grinding is performed with 50% by weight of distilled water in jars in ZrO2 to obtain a powder with a particle size of 10 xcexcm. The reagent powder is then compacted to 400 MPa (4000 bar) with the application of slow and progressive pressure (20 MPa/min; 200 bar/min). This makes it possible to increase the thermal conductivity of the powder and the calcination will be affected. The reaction time for a given temperature and pressure will be decreased. The pellet obtained is then calcined at 1500xc2x0 C. for 6 hours in a nitrogen atmosphere. Under these conditions, there is no loss of fluorine due to volatility during the reagent sintering. Ca9.46 Gd0.08 Pu0.46 (PO4)5 SiO4 F2xe2x80x83xe2x80x83V. In this case, the same procedure as for example 1 is followed, but the reagents used to prepare the first mixture are present in the following proportions: CaCO3: 2.7945 g PuO2: 1.1425 g SiO2: 0.5446 g Ca2P2O7: 5.7585 g, and Na2CO3: 0.4804 g. After heat treatment to break down the calcium carbonate, 0.7078 g of CaF2 is added and the final mixture of the powders is performed, as in example 1. A homogeneous dense ceramic containing plutonium and gadolinium is thus obtained. Ca9.04Gd0.48Pu0.48(PO4)4.56(SiO4)1.44F2xe2x80x83xe2x80x83VII To obtain 10 g of britholite corresponding to the above formula, the following reagents in the following proportions are used to prepare the first mixture: CaCO3: 3.0089 g PuO2: 1.1361 g SiO2: 0.7474 g Ca2P2O7: 5.0047 g, and Gd2O3: 0.7515 g. All these reagents are mixed in acetone and dried in an oven as in example 1. They are then ground to obtain a particle size of approximately 50 xcexcm and the mixture is heated to 900xc2x0 C. to break down the carbonates. After cooling, 0.6745 g of CaF2 is added and the final mixture and grinding are performed as in example 1. The powder obtained is shaped in a carbon mould using a piston and the mould is then heated by induction. A pressure of 25 MPa is then applied at the end of the 15 minute stage at 700xc2x0 C. and calcination is continued at a temperature of the order of 1100xc2x0 C. for one hour, applying a pressure of 25 MPa. If the homogeneity of the matrix is not satisfactory, the pellet undergoes fine grinding, followed by annealing at a very high temperature (1600xc2x0 C.) in a neutral atmosphere without any risk of loss of fluorine. Ca9.55PU0.45(PO4)5.1(SiO4)0.9F2xe2x80x83xe2x80x83IX. In this example, the same procedure as in example 3 is followed using the following quantities of reagents: CaCO3: 3.1481 g PuO2: 1.1241 g SiO2: 0.4930 g Ca2P2O7: 5.9073 g, and CaF2: 0.7118 g. The product obtained following the pressurised sintering is a dense, homogeneous ceramic wherein all the fluorine is incorporated. It is to be noted that the improved incorporation of fluorine in the method according to the invention is due to the use of a neutral or reducing atmosphere which does not favour fluorine-oxygen exchanges, and due to the fact that the synthesis and densification are carried out in only one step at a high temperature. The dense ceramics obtained in this way are more homogeneous since the calcination and/or annealing temperatures are higher. These two improvements made to the method described in document [1] improve the conditioning of plutonium considerably. In addition to the intrinsic properties offered by the present invention, additional confinement properties are offered in that the products obtained come in the form of dense monoliths, which reduces the exchange surface for leaching. In addition, according to the invention, it is possible to add a neutrophage product such as Hf or a neutron poison such as Gd in the form of microinclusions or as a substitution to reduce criticality risks. [1]: WO-A-95/02886.
	summary
	abstract	An exposure apparatus includes a projection optical system for projecting a pattern of an original onto a substrate, a stage for holding the substrate, a cover for substantially surrounding an exposure light path, from an end portion of the projection optical system, at a side facing the stage, to the stage, a first supply port provided inside the cover, for supplying a purge gas into a space surrounded by the cover, and a first exhaust port provided in an end portion of the cover at a side facing the stage, for exhausting the gas.
	claims	1. A reactor oscillation power range monitor comprising:a receiving unit which receives local power range monitor (LPRM) signals generated from a plurality of LPRM detectors provided in a reactor core, the LPRM detectors distributed over the entire reactor core into several groups in a regular manner, each group classified as a cell and each of the LPRM signals allocated to a specified cell;an exclusion processing unit which searches the LPRM signals allocated to each cell for an LPRM signal corresponding to an exceptional condition, wherein the exceptional condition determines a LPRM signal unsuitable for a power oscillation monitoring;an averaging unit which averages the allocated LPRM signals for each of the cells by excluding the LPRM signals corresponding to the exceptional condition and outputs an average flux value;a time averaging unit which calculates a time average of the average flux value and outputs a time averaged flux value;a normalized value calculation unit which divides the average flux value by the time averaged flux value and outputs a normalized value;an initialization unit which outputs an initialization signal when a value of an LPRM signal changes to correspond or not correspond to the exceptional condition, the initialization signal identifying the cell allocated to the LPRM signal;a determination unit which derives at least one of amplitude and cycle of the power oscillation from the normalized value and performs determination of nuclear thermal hydraulic instability based on a predetermined algorithm; andin response to the initialization signal, the normalized value calculation unit outputs a constant value instead of the normalized value of the cell identified by the initialization signal. 2. The reactor oscillation power range monitor according to claim 1, wherein the determination unit is configured to initialize the predetermined algorithm in response to the initialization signal. 3. The reactor oscillation power range monitor according to claim 1, wherein the normalized value calculation unit is configured to continue outputting the constant outputted in response to the initialization signal until at least all LPRM signals subjected to calculation of the normalized value become the same. 4. The reactor oscillation power range monitor according to claim 1, further comprising a timing control unit which causes the determination unit to initialize the algorithm during a period in which the constant continues to be outputted from the normalized value calculation unit. 5. The reactor oscillation power range monitor according to claim 4, whereinthe timing control unit sets the period in which the constant continues to be outputted from the normalized value calculation unit. 6. A reactor power oscillation monitoring method comprising the steps of:receiving local power range monitor (LPRM) signals generated from a plurality of LPRM detectors provided in a reactor core, the LPRM detectors distributed over the entire reactor core into several groups in a regular manner, each group classified as a cell and each of the LPRM signals allocated to a specified cell;searching the LPRM signals allocated to each cell for an LPRM signal corresponding to an exceptional condition;outputting an average flux value by averaging the allocated LPRM signals for each of the cells by excluding the LPRM signals corresponding to the exceptional condition, wherein the exceptional condition determines a LPRM signal unsuitable for a power oscillation monitoring;outputting a time averaged flux value by calculating a time average of the average flux value;outputting a normalized value by dividing the average flux value by the time averaged flux value;outputting an initialization signal identifying the cell allocated to an LPRM signal having a value which changes to correspond or not correspond to the exceptional condition; andperforming determination based on a predetermined algorithm by deriving at least one of amplitude and cycle of the power oscillation from the normalized value of nuclear thermal hydraulic instability.
	abstract	It is an object of one of the inventions to acquire a radiation image in which a stripe pattern originating from a scattered ray removing grid is less apt to interfere with observation. An image acquisition apparatus of one of the inventions includes a sensor for spatially sampling a radiation transmission distribution of an object to be imaged at a spatial sampling interval and acquiring an image of the object, and a scattered ray removing grid for removing scattered rays from the object, wherein an interval of elements of the scattered ray removing grid is set such that a spatial frequency of a stripe pattern, in the image, which originates from the scattered ray removing grid becomes not greater than 40% of a sampling frequency that is a reciprocal of the spatial sampling interval.
	summary
	abstract	A pharmaceutical pig is used to transport a syringe containing a liquid radiopharmaceutical from a radiopharmacy to a medical facility for administration to a patient. The pharmaceutical pig includes an elongate polymer cap that is removably attached to an elongate polymer base. The elongate polymer cap includes a cap shell that completely encloses a cap shielding element and the elongate polymer base includes a base shell that completely encloses a base shielding element. Preferably the polymer utilized for the cap shell and the base shell is polycarbonate resin, e.g., LEXAN®. An inner liner is not utilized and the cap shielding element and the base shielding element, which are preferably, but not necessarily, made of lead, are completely sealed and unexposed.
	summary
	claims	1. A refractive arrangement for X-rays comprising: a member of low-Z material, said member of low-Z material having a first end adapted to receive X-rays emitted from an X-ray source and a second end from which said X-rays, received at said first end, emerge and first and second surfaces wherein said arrangement further comprises a plurality of substantially sawtooth formed triangular grooves disposed, between at least part of said first end and second end, on at least one of said first or second surfaces, said plurality of grooves oriented such that said X-rays, which are received at said first end, pass through said member of low-Z material and said plurality of grooves, and emerge from said second end, are refracted to a focal point. 2. The arrangement of claim 1 , characterized in, that said member of low-Z material consists of a plastic material, specially one of from the group comprising polymethylmethacrylate, vinyl and PVC. claim 1 3. The arrangement of claim 1 , characterized in, that said member of low-Z material consists of beryllium. claim 1 4. The arrangement according to claim 1 , characterized in, that said grooves have the form of sawteeth with substantially straight cuts. claim 1 5. The arrangement according to claim 1 , characterized in, that said pluralities of grooves have varying sizes, decreasing or increasing continuously from said first end towards said second end. claim 1 6. A mammography x-ray apparatus including a refractive arrangement according to claim 1 . claim 1 7. A refractive X-ray lens comprising: a volume of low-Z material, said volume having a first end adapted to receive X-rays emitted from an X-ray source and a second end from which said X-rays received at said first end, emerge and first and second surfaces wherein said volume further comprises a plurality of substantially sawtooth formed triangular grooves disposed between at least part of said first end and second end, on at least one of said first and second surfaces, said plurality of grooves oriented such that said X-rays which are received at said first end, pass through said volume of low-Z material and said plurality of grooves, and emerge from said second end, are refracted to a focal point. 8. The lens according to claim 7 , characterized in that the lens comprises of two volumes arranged such that the surfaces with the plurality of grooves are facing each other. claim 7 9. The lens according to claim 8 , characterized in that said two volumes each have a tilt angle to an optical axis of said X-ray. claim 8 10. The lens according to claim 9 , characterized in that a focal length of each of the two volumes of the lens is varied by separately varying each tilt angle. claim 9 11. The lens according to claim 9 , characterized in, that said volume of low-Z material consists of beryllium. claim 9 12. The lens according to claim 8 , characterized in that said volumes have non-coincident focal points. claim 8 13. The lens according to claim 7 , characterized in that said volume of low-Z material consists of a plastic material, specially one from the group comprising polymethylmethacrylate, vinyl or PVC. claim 7 14. An X-ray system for two-dimensional focusing of X-rays and including at least two lenses according to claim 7 , characterized in that the focusing is obtained by arranging said at least two lenses, such that each x-ray traverses both of lenses in sequence and that one of said at least two lenses are rotated around an optical axis with respect to the other lens. claim 7 15. A method of providing two-dimensional focusing by using two saw-tooth profile refractive x-ray lenses according to claim 7 , such that each x-ray will traverse both of them in sequence and such that the said second saw-tooth profile refractive x-ray lens is rotated around the optical axis with respect to the said first saw-tooth profile refractive x-ray lens. claim 7 16. The lens of claim 7 , characterized in that said refractive lens is coupled to at least one second commercial-grade compound refractive x-ray lens such that an array of compound refractive x-ray lenses is formed. claim 7 17. A method for providing a bimodal energy distribution from an X-ray source using the saw-tooth profile refractive x-ray lens of claim 7 . claim 7 18. A mammography x-ray apparatus including a lens arrangement according to claim 7 . claim 7 19. An x-ray crystallography arrangement including a lens arrangement according to claim 7 . claim 7 20. An x-ray microscope arrangement including a lens arrangement according to claim 7 . claim 7 21. A method for fabricating a sawtooth triangular profile refractive X-ray lens wherein transferring shapes of triangular grooves onto a carrier by means of an engraving arrangement is performed, producing a master, and using said master for pressing grooves on a suitable material. 22. The method according to claim 21 , characterized in that said material is vinyl or PVC. claim 21 23. A refractive arrangement for X-rays comprising: a member of low-Z material, said member of low-Z material having a first end adapted to receive X-rays emitted from an X-ray source and a second end from which emerge said X-rays received at said first end, and first and second surfaces characterized in that it further comprises a plurality of substantially sawtooth formed grooves disposed between said first and second ends on at least one of said first or second surfaces, said plurality of grooves oriented such that said X-rays which are received at said first end, pass through said member of low-Z material and said plurality of grooves, and emerge from said second end, are refracted to a focal point, further characterized in that said pluralities of grooves have varying sizes, decreasing or increasing continuously from said first end towards said second end. 24. A refractive X-ray lens comprising: a volume of low-Z material, said volume having a first end adapted to receive X-rays emitted from an X-ray source and a second end from which emerge said X-rays received at said first end and first and second surfaces, characterized in that said volume further comprises a plurality of substantially saw-tooth formed grooves disposed between said first and second ends on at least one of said at least two surfaces, said plurality of grooves oriented such that said X-rays which are received at said first end, pass through said volume of low-Z material and said plurality of grooves, and emerge from said second end, are refracted to a focal point, further characterized in that the lens comprises of two volumes arranged such that the surfaces with the plurality of grooves are facing each other, further characterized in that said two volumes each have a tilt angle relative to an optical axis of said X-ray. 25. A refractive X-ray lens comprising: a volume of low-Z material, said volume having a first end adapted to receive X-rays emitted from an X-ray source and a second end from which emerge said X-rays received at said first end and first and second surfaces, characterized in that said volume further comprises a plurality of substantially saw-tooth formed grooves disposed between said first and second ends on at least one of said at least two surfaces, said plurality of grooves oriented such that said X-rays which are received at said first end, pass through said volume of low-Z material and said plurality of grooves, and emerge from said second end, are refracted to a focal point, further characterized in that the lens comprises of two volumes arranged such that the surfaces with the plurality of grooves are facing each other, further characterized in that said volumes have non-coincident focal points. 26. The lens according to claim 24 , characterized in that a focal length of each of the two volumes of the lens is varied by separately varying each tilt angle. claim 24 27. The lens according to claim 24 , characterized in that said volume of low-Z material consists of beryllium. claim 24 28. An X-ray system for two-dimensional focusing of X-rays and including at least two refractive X-ray lenses, each lens comprising: a volume of low-Z material, said volume having a first end adapted to receive X-rays emitted from an X-ray source and a second end from which emerge said X-rays received at said first end and first and second surfaces, characterized in that said volume further comprises a plurality of substantially saw-tooth formed grooves disposed between said first and second ends on at least one of said at least two surfaces, said plurality of grooves oriented such that said X-rays which are received at said first end, pass through said volume of low-Z material and said plurality of grooves, and emerge from said second end, are refracted to a focal point, characterized in that the focusing is obtained by arranging said at least two lenses, such that each X-ray traverses both of lenses in sequence and that one of said at least two lenses is rotated around an optical axis with respect to the other lens. 29. A method of providing two-dimensional focusing by using two saw-tooth profile refractive X-ray lenses, each lens comprising: a volume of low-Z material, said volume having a first end adapted to receive X-rays emitted from an X-ray source and a second end from which emerge said X-rays received at said first end and first and second surfaces, characterized in that said volume further comprises a plurality of substantially saw-tooth formed grooves disposed between said first and second ends on at least one of said at least two surfaces, said plurality of grooves oriented such that said X-rays which are received at said first end, pass through said volume of low-Z material and said plurality of grooves, and emerge from said second end, are refracted to a focal point, such that each X-ray will traverse both of them in sequence and such that the said second saw-tooth profile refractive X-ray lens is rotated around ab optical axis with respect to the said first saw-tooth profile refractive X-ray lens. 30. A refractive X-ray lens comprising: a volume of low-Z material, said volume having a first end adapted to receive X-rays emitted from an X-ray source and a second end from which emerge said X-rays received at said first end and first and second surfaces, characterized in that said volume further comprises a plurality of substantially saw-tooth formed grooves disposed between said first and second ends on at least one of said at least two surfaces, said plurality of grooves oriented such that said X-rays which are received at said first end, pass through said volume of low-Z material and said plurality of grooves, and emerge from said second end, are refracted to a focal point, further characterized in that said refractive lens is coupled to at least one second commercial-grade compound refractive X-ray lens such that an array of compound refractive X-ray lenses is formed.
047605901	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a multioperation accelerator of simple design, usable more particularly in radiotherapy for treatments using low or average amounts of energy. 2. Description of the Prior art In radiotherapy a distinction is made, among others, of two types of equipment, the radiation generators using radioactive sources, such for example as cobalt, and the particle (particularly electron) accelerators. These latter offer a great flexibility of use and allow high energies to be reached up to 40 MeV electrons and 25 MeV photons. However, such apparatus are costly. Particularly, the systems for adjusting and varying the power of the beam (so as to obtain the different operating conditions) acting on the acceleration parameters, particularly the HF power, have a great influence on the cost price of the installation. Furthermore, the cobalt generator has its own particular qualities which means that it is very greatly appreciated by doctors although handling of the radioactive sources requires precautions. The radiation of the cobalt is a photon radiation which is very penetrating despite a low energy (1.3 MeV photons) since 50% of the maximum dose is still available at a depth of 12 cm in the tissue. On the other hand, the "skin dose" is relatively high which means, in certain cases, surface irradiation which is too high with consequent risks of burning. Now, at the present time, it is possible to construct accelerator structures capable of supplying the electron energy (about 4 MeV) required for obtaining 1.3 MeV photons as with cobalt, and this for a relatively low cost price. SUMMARY OF THE INVENTION One of the aims of the invention consists then in perfecting a radiotherapy unit using a photon beam produced from an accelerator but whose characteristics are fairly close to those of cobalt with however additional facilities and particularly that of being able to use several types of beam. For example, a beam may be required having the same characteristics as cobalt radiation and also other beams having closely related characteristics, in particular improved characteristics in so far as the problem of the "skin dose" is concerned. Another aim of the invention is to provide a system of low cost price, of the same order of size as a cobalt generator. According to the general principle of the invention, the power of the accelerator remains constant (thus saving on the systems for adjusting the high frequency wave) whereas variations in operating conditions and characteristics of the beam are obtained by switching targets and/or filters at the output of the accelerator. More precisely, the invention provides a multioperation accelerator of the particle beam type comprising a target bombarded by said particle beam so as to generate a photon beam, wherein the HF power for supplying said accelerator is fixed at a predetermined level and it comprises several switchable targets and/or filters at the output of said accelerator, allowing a predetermined number of target-filter combinations to which correspond as many photon beams with different chosen characteristics.
	summary
	claims	1. A method of manufacturing nuclear fuel cladding comprising:depositing nanoparticles on a base cladding to form at least one nanomaterial layer, the nanoparticles having an average grain size of between 5 to 400 nanometers,the at least one nanomaterial layer including two nanomaterial layers, each having a different composition, the two nanomaterial layers including a first nanomaterial layer formed of first nanoparticles and a second nanomaterial formed of second nanoparticles,the depositing of nanoparticles on the base cladding comprising:depositing the first nanoparticles on an outer surface of the base cladding to form the first nanomaterial layer, the first nanoparticles consisting of one of metal nanoparticles or ceramic nanoparticles, anddepositing the second nanoparticles on an outer surface of the first nanomaterial layer to form the second nanomaterial layer, the second nanoparticles consisting of the other of metal nanoparticles or ceramic nanoparticles. 2. The method as recited in claim 1 wherein the depositing includes electrochemically depositing the nanoparticles on the base cladding. 3. The method as recited in claim 1 wherein the depositing comprises:activating the base cladding such that a native surface layer of base cladding is removed;forming a pre-filming layer on the base cladding after the native surface layer is removed; andelectrochemically depositing the nanoparticles on the pre-filming layer. 4. The method as recited in claim 3 wherein the electrochemically depositing the nanoparticles on the pre-filming layer comprises adding an additive to limit grain sizes of the nanomaterial layer by preventing crystal growth past a predetermined upper limit. 5. The method as recited in claim 1 wherein the base cladding is formed of a zirconium alloy. 6. The method as recited in claim 1 further comprising nanostructuring the base cladding before depositing the nanoparticles on the base cladding. 7. The method as recited in claim 1 wherein the nanomaterial layer has a thickness of two to one hundred times an average grain size of the base cladding. 8. The method as recited in claim 7 wherein the base cladding has an average grain size between 4 and 70 μm.
062158538	summary	CROSS-REFERENCE TO RELATED APPLICATIONS Not applicable. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT Not applicable. BACKGROUND OF THE INVENTION The present invention generally relates to medical diagnostic imaging systems, and in particular to X-ray collimator sizing and alignment in an X-ray imaging system employing a solid state X-ray detector. Conventional X-ray imaging has found wide use in the medical diagnostic imaging industry. X-ray imaging systems are commonly used to capture, as examples, thoracic, cervical, spinal, cranial, and abdominal images that often include the information necessary for a doctor to make an accurate diagnosis. When having a thoracic X-ray image taken, for example, a patient stands with his or her chest against an X-ray sensor as an X-ray technologist positions the X-ray sensor and an X-ray source at an appropriate height. The X-ray energy generated by the source and attenuated to various degrees by different parts of the body, passes through the body and is detected by the X-ray sensor. An associated control system (where the X-ray sensor is a solid state imager) scans the detected X-ray energy and prepares a corresponding diagnostic image on a display. If the X-ray sensor is conventional film, the film is subsequently developed and displayed using a backlight. Regulatory requirements mandate that imaging systems limit the X-ray field generated by the X-ray tube to an area that the X-ray sensor can acquire. X-ray imaging systems therefore use a collimator between the X-ray tube and the patient to constrain the X-ray field. To this end, the collimator may be constructed using horizontal and vertical lead blades that form an opening accurately corresponding to the X-ray sensor or desired anatomical area. During system calibration one must insure that the collimator blades can not be positioned at a size or orientation that allows imaging outside of the X-ray sensor. Furthermore, it is also of great importance that the horizontal and vertical blades are centered within the area of the X-ray sensor. These safeguards are required to prevent undesirable or unnecessary exposure of the patient to X-ray energy, and to insure excellent image quality. In the past, however, the X-ray sensor was an X-ray sensitive screen and film combination. During system calibration a field engineer manually estimated the collimator sizing and centering using a field light positioned within the collimator. The field engineer then verified the calibration by exposing and developing the film. If measurements taken on the developed film indicated inappropriate collimator positioning, then the field engineer had to repeat the calibration process, after using a mechanical linkage and a screwdriver to manually adjust the collimator blade sizing and alignment. In the past, it was not uncommon for a single attempt at collimator calibration to require 5 or 6 minutes or more, and, taking into account repetition to ensure correct collimator sizing and alignment, as much as 30 minutes or more to finish calibration for a single size of film. Because most X-ray imaging systems are flexible enough to use numerous sizes and orientations of film (e.g., 14.times.17 and 17.times.14, 11.times.14 and 14.times.11, 8.times.10 and 10.times.8, as well as 5.times.7 and 7.times.5 inches), the field engineer required a significant amount of time to perform a complete collimator calibration. In addition, every calibration resulted in wasted film that could have been used to capture a diagnostic image for a doctor, and the accuracy attainable through manual collimator sizing and alignment was limited by human error. A need has long existed for a method and apparatus for X-ray collimator sizing and alignment that overcomes the disadvantages discussed above and others previously experienced. SUMMARY OF THE INVENTION A preferred embodiment of the present invention provides a method for calibrating the size and alignment of a collimator. The method includes the step of acquiring a digital image showing collimator blades in front of a region of interest. An X-ray solid state image sensor typically obtains the image, and the region of interest may correspond, for example, to a desired image or exposure size on the image sensor. The method then determines the position of one or more of the collimator blades or collimator assembly shown in the digital image. To this end, the method may determine the width between pairs of blades, as well as the rotation associated with one or more of the blades. The method may then adjust the position of one or more collimator blades to expose the region of interest. Calibration may proceed over any predetermined number of exposure sizes. A preferred embodiment of the present invention also provides a collimator calibration subsystem. The calibration subsystem includes a communication interface that exchanges data with collimator blade sensors, collimator blade actuators, and an image sensor. The calibration processor preferably includes a central processor coupled to a memory and the communication interface. The memory may include instructions for acquiring a digital image from the image sensor that shows the collimator blades in front of a region of interest, instructions for determining the position of the collimator blades, and instructions for adjusting a position of a collimator blade to expose the region of interest. Both the method and apparatus of the preferred embodiment may iteratively acquire an image, determine the position of the collimator blades, and adjust the positions of the collimator blades until the collimator reaches a predetermined size and alignment within a predetermined degree of accuracy.
042740070	abstract	A transport or storage canister for radioactive wastes has an upright one-piece cast iron or steel vessel with an upwardly open mouth adapted to receive a complementary, stepped plug-type cover which is overlain by a safety cover which peripherally overhangs the plug cover and is likewise recessed in the top of the body. Seals are provided between the several steps so that respective gaps or compartments are formed, the compartments communicating with a fitting in the body which enables monitoring or control units to be connected to the compartments to determine whether leakage may have occurred.
	abstract	Nuclear reactor systems and methods are described having many unique features tailored to address the special conditions and needs of emerging markets. The fast neutron spectrum nuclear reactor system may include a reactor having a reactor tank. A reactor core may be located within the reactor tank. The reactor core may include a fuel column of metal or cermet fuel using liquid sodium as a heat transfer medium. A pump may circulate the liquid sodium through a heat exchanger. The system may include a balance of plant with no nuclear safety function. The reactor may be modular, and may produce approximately 100 MWe.
	claims	1. A process of recycling sodium salt in a wet reprocessing process of a spent nuclear fuel, comprising:a neutralization step in which a nitric acid liquid waste or an off-gas having nitric acid dissolved therein which is produced through a wet reprocessing process comprising a dissolution step for dissolving a spent nuclear fuel in nitric acid is neutralized by adding or contacting one or more sodium salts selected from the group consisting of sodium hydroxide, sodium hydrogencarbonate and sodium carbonate to or with the nitric acid liquid waste or the off-gas, thereby yielding a sodium nitrate liquid waste;a sodium nitrate-decomposition step in which the sodium nitrate liquid waste obtained in the neutralization step is reductively decomposed with a reducing agent, thereby decomposing sodium nitrate into a nitrogen gas and the sodium salt(s); anda recycle step for recycling the sodium salt(s) produced in the sodium nitrate-decomposition step into the neutralization step or the wet reprocessing process,wherein the reductive decomposition in the sodium nitrate-decomposition step is carried out by reductive decomposition using a reducing agent and a catalyst or by reductive decomposition using a reducing agent under supercritical conditions where water serves as a supercritical fluid. 2. The process according to claim 1, further comprising an evaporative concentration step in which the sodium nitrate liquid waste obtained in the neutralization step is concentrated by evaporation, and the concentrated sodium nitrate liquid waste obtained in the evaporative concentration step is reductively decomposed in the sodium nitrate-decomposition step. 3. The process according to claim 1, wherein a part of the sodium salt(s) to be recycled in the recycle step is brought and mixed in a solidified substance of a radioactive waste for solidification. 4. The process according to claim 1, wherein a part of the sodium salt(s) to be recycled in the recycle step is brought and mixed in a vitrified waste of a high-level radioactive waste for use as a part of a glass raw material. 5. A process of recycling sodium salt in a wet reprocessing process of a spent nuclear fuel, comprising:an organic solvent washing step in which an organic solvent used in a wet reprocessing process of a spent nuclear fuel is washed with one or more sodium salts selected from the group consisting of sodium hydroxide, sodium hydrogencarbonate and sodium carbonate;a neutralization step in which a liquid waste of the sodium salt(s) produced in the organic solvent washing step is neutralized with nitric acid, thereby yielding a sodium nitrate liquid waste;a sodium nitrate-decomposition step in which the sodium nitrate liquid waste produced in the neutralization step is reductively decomposed with a reducing agent, thereby decomposing sodium nitrate into a nitrogen gas and the sodium salt(s); anda recycle step for recycling the sodium salt(s) produced in the sodium nitrate-decomposition step into the organic solvent washing step or the wet reprocessing process,wherein the reductive decomposition in the sodium nitrate-decomposition step is carried out by reductive decomposition using a reducing agent and a catalyst or by reductive decomposition using a reducing agent under supercritical conditions where water serves as a supercritical fluid. 6. The process according to claim 5, further comprising an evaporative concentration step in which the sodium nitrate liquid waste obtained in the neutralization step is concentrated by evaporation, and the concentrated sodium nitrate liquid waste obtained in the evaporative concentration step is reductively decomposed in the sodium nitrate-decomposition step. 7. The process according to claim 5, wherein a part of the sodium salt(s) to be recycled in the recycle step is brought and mixed in a solidified substance of a radioactive waste for solidification. 8. The process according to claim 5, wherein a part of the sodium salt(s) to be recycled in the recycle step is brought and mixed in a vitrified waste of a high-level radioactive waste for use as a part of a glass raw material. 9. The process according to any one of claims 1 to 6, wherein a part of the sodium salt(s) to be recycled in the recycle step is brought and mixed in a solidified substance of a radioactive waste for solidification. 10. The process according to any one of claims 1 to 6, wherein a part of the sodium salt(s) to be recycled in the recycle step is brought and mixed in a vitrified waste of a high-level radioactive waste for use as a part of a glass raw material.
	claims	1. A method of manufacturing a grid for selective transmission of electromagnetic radiation, the method comprising:providing a structural element that has minimum structure dimensios and comprises a plurality of particles of a first radiation-absorbing material, wherein at least 90% of all particles of the plurality of particles have a maximum particle size larger than 10% of the minimum structure dimensions, further wherein the particles are sintered together and pores are present between neighbouring particles;inserting a liquid second material into the pores, wherein the second material has a melting temperature lower than a melting temperature of the first radiation-absorbing material; andsolidifying the second material. 2. The method according to claim 1, wherein the liquid second material comprises a radiation-absorbing material. 3. The method according to claim 1, wherein the particles of the first radiation-absorbing material are sintered together by selective laser sintering. 4. The method according to claim 1, wherein the liquid second material is inserted into the pores by dipping the structural element into a bath of liquefied material. 5. The method according to claim 1, wherein the liquid second material is liquefied by melting. 6. A grid for selective transmission of electromagnetic radiation comprising a structural element that has minimum structure dimensions and comprises a plurality of particles of a first radiation-absorbing material, wherein at least 90% of all particles of the plurality of particles are larger than 10% of the minimum structure dimensions, further wherein the particles are sintered together such that pores are present between neighbouring particles and wherein the pores are at least partially filled with a second solid material, and further wherein the second material has a melting temperature lower than a melting temperature of the first radiation-absorbing material. 7. The grid according to claim 6, wherein the second material is a radiation-absorbing material. 8. The grid according to claim 6, wherein the second material is a metal. 9. The grid of according to claim 6, wherein the second material is selected out of a group consisting of of silver, lead, copper and alloys thereof. 10. The grid of according to claim 6, wherein the first radiation-absorbing material is selected out of a group comprising molybdenum and tungsten. 11. A medical imaging device comprising a grid according to claim 6.
	claims	1. An ionizing radiation tolerant camera, comprising:a camera module comprising, an electronic image sensor and a lens package, said electronic image sensor and lens package are in fixed alignment to each other,an ionizing radiation shielding enclosure within which said camera module is disposed, said ionizing radiation shielding enclosure defining an opening for allowing passage of light into said ionizing radiation shielding enclosure and to the image sensor,an ionizing radiation shield,a heat absorbing cooling element connected to the camera module, said cooling element functioning to dissipate heat from the camera module,a pivot structure for simultaneously pivoting the ionizing radiation shielding enclosure together with the camera module, with the electronic image sensor and lens package within the ionizing radiation shielding enclosure, as a unit, relative to the ionizing radiation shield between an adjustable active position in which the ionizing radiation shielding enclosure opening is uncovered, and a shielded position in which the ionizing radiation shielding enclosure opening is directed towards the ionizing radiation shield; anda support structure on which the ionizing radiation shield is mounted and on which the pivot structure is mounted to enable the ionizing radiation shield and the ionizing radiation shielding enclosure, with the camera module therein, to move together in a desired rotational pan direction. 2. An ionizing radiation tolerant camera as claimed in claim 1, wherein the heat absorbing cooling element is thermally connected to a cooling device. 3. An ionizing radiation tolerant camera as claimed in claim 2, wherein the cooling device comprises a thermoelectric cooling module. 4. An ionizing radiation tolerant camera as claimed in claim 1, wherein heat pipes are provided for dissipation of heat from the heat absorbing cooling element to a position outside of the ionizing radiation shielding enclosure. 5. An ionizing radiation tolerant camera as claimed in claim 4, wherein the heat pipes extend substantially horizontally. 6. An ionizing radiation tolerant camera as claimed in claim 4, wherein the heat pipes are connected to a heat sink mounted on an outside wall of the enclosure. 7. An ionizing radiation tolerant camera as claimed in claim 1, wherein the ionizing radiation shielding enclosure is made from a material comprising hydrocarbon plastics. 8. An ionizing radiation tolerant camera as claimed in claim 7, wherein the ionizing radiation shielding enclosure is made from a material comprising boron. 9. An ionizing radiation tolerant camera as claimed in claim 1, wherein the ionizing radiation shielding enclosure has an average thickness of 3-10 cm. 10. An ionizing radiation tolerant camera as claimed in claim 9, wherein the ionizing radiation shielding enclosure has an average thickness of about 5 cm. 11. An ionizing radiation tolerant camera as claimed in claim 1, wherein the opening is covered by a transparent front panel. 12. An ionizing radiation tolerant camera as claimed in claim 1, wherein the camera module is arranged in an insulating and moisture-proof body. 13. An ionizing radiation tolerant camera as claimed in claim 12, wherein the camera module is enclosed in a housing. 14. An ionizing radiation tolerant camera as claimed in claim 13, wherein the housing comprises neutron radiation shielding material. 15. An ionizing radiation tolerant camera as claimed in claim 12, wherein the camera module is enclosed in a gamma radiation shielding layer. 16. An ionizing radiation tolerant camera as claimed in claim 1,further comprises a motorized actuator for said pivot structure; andthe ionizing radiation shielding enclosure with the camera module disposed therein, is powered by said motorized actuator to pivot as a unit in relation to said ionizing radiation shield between a shielded position in which the opening of the ionizing radiation shielding enclosure is directed toward said ionizing radiation shield and the adjustable operating position in which the opening of the ionizing radiation shielding enclosure is uncovered.
	claims	1. A scanning probe microscope (SPM) comprising:a first scanner that has a probe carrier holder, and changes a position of the probe carrier holder along a straight line;a second scanner that is decoupled from the first scanner and changes a position of a sample within a plane; anda tray configured to store a spare probe carrier and a spare probe attached to the spare probe carrier,wherein the probe carrier holder includes a plurality of protrusions that are configured for engagement with corresponding holes formed on the spare probe carrier. 2. The SPM of claim 1, further comprising:a probe carrier and a probe attached to the probe carrier,wherein the probe carrier can be attached to the probe carrier holder and detached from the probe carrier holder, and includes a plurality of holes corresponding to the protrusions of the probe carrier holder. 3. The SPM of claim 2, wherein the probe carrier is formed of metal. 4. The SPM of claim 1, wherein the tray includes a plurality of protrusions. 5. The SPM of claim 4, further comprising:a probe carrier and a probe attached to the probe carrier,wherein the probe carrier can be attached to the probe carrier holder and detached from the probe carrier holder, and includes a plurality of holes corresponding to the protrusions of the probe carrier holder and to the protrusions of the tray. 6. The SPM of claim 4, wherein the probe carrier is formed of metal. 7. The SPM of claim 1, wherein the probe carrier holder is formed of a permanent magnet or an electromagnet, includes a portion formed of a permanent magnet or an electromagnet, or includes a vacuum chuck. 8. The SPM of claim 1, wherein the tray is formed of a permanent magnet or an electromagnet, or includes a portion formed of a permanent magnet or an electromagnet. 9. The SPM of claim 1, wherein the probe carrier holder includes three protrusions that are hemispherical. 10. A scanning probe microscope (SPM) comprising:a first scanner that has a probe carrier holder, and changes a position of the probe carrier holder along a straight line;a second scanner that is decoupled from the first scanner and changes a position of a sample within a plane; anda tray configured to store a spare probe carrier and a spare probe attached to the spare probe carrier,wherein the probe carrier holder includes a plurality of protrusions that are configured for engagement with corresponding recesses formed on the spare probe carrier. 11. The SPM of claim 10, further comprising:a probe carrier and a probe attached to the probe carrier,wherein the probe carrier can be attached to the probe carrier holder and detached from the probe carrier holder, and includes a plurality of recesses corresponding to the protrusions of the probe carrier holder. 12. The SPM of claim 11, wherein the probe carrier is formed of metal. 13. The SPM of claim 10, wherein the tray includes a plurality of protrusions. 14. The SPM of claim 13, further comprising:a probe carrier and a probe attached to the probe carrier,wherein the probe carrier can be attached to the probe carrier holder and detached from the probe carrier holder, and includes a plurality of recesses corresponding to the protrusions of the probe carrier holder and to the protrusions of the tray. 15. The SPM of claim 13, wherein the probe carrier is formed of metal. 16. The SPM of claim 10, wherein the probe carrier holder is formed of a permanent magnet or an electromagnet, includes a portion formed of a permanent magnet or an electromagnet, or includes a vacuum chuck. 17. The SPM of claim 10, wherein the tray is formed of a permanent magnet or an electromagnet, or includes a portion formed of a permanent magnet or an electromagnet. 18. The SPM of claim 10, wherein the probe carrier holder includes three protrusions that are hemispherical. 19. A scanning probe microscope (SPM) comprising:a tray configured to store a plurality of probe carriers,a first scanner that changes a position of a probe carrier that is attached thereto along a straight line;a second scanner that is decoupled from the first scanner and changes a position of a sample within a plane; andwherein the probe carriers each have female engagement portions that are configured to mate with male engagement portions disposed on the first scanner and the tray. 20. The SPM of claim 19, wherein the female engagement portions are holes or recesses and the male engagement portions are hemispherical projections.
	summary
	claims	1. A laser welding apparatus comprising:a welding head including a head body, and a collimate lens opposite to an end face of an optical fiber connected to the head body and installed in the head body; anda welding head scanning apparatus of scanning the welding head;wherein a laser path of introducing a laser emitted from the optical fiber and passing through the collimate lens is formed in the head body;wherein the welding head includes no lenses except the collimate lens;wherein a laser outlet of the laser path is formed in an end portion of the head body;wherein the laser outlet has a size that allows the laser, which is a parallel beam converted by the collimate lens, to pass through the laser outlet;wherein a powder feed path of introducing metallic powder which is a filler metal is formed in the head body, the powder feed path being contained entirely within the head body; andwherein an injection outlet of the powder feed path is formed in the end portion of the head body. 2. The laser welding apparatus according to claim 1, wherein the powder feed path includes a first portion parallel to the laser path and a second portion arranged at an acute angle to the laser path.

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