Device for storing target substance and method for producing target nuclide

Abstract

A storage device (10) for storing a target substance (1), which is an irradiation target of a particle beam, comprises: a target container (3) in which an internal space (3a) having an upper opening (3a1) and a lower bottom surface (3a2) is formed; and a sealing member (5a) which is attached to the target container (3) so as to close the opening (3a1) and seal the internal space (3a), and can transmit the particle beam. The bottom surface (3a2) includes a recess (D) recessed downward, and the target substance (1) is disposed in the recess (D).

Description

Target material storage device and method for producing target nuclides

[0001] The present invention relates to a storage device for storing a target material that is an irradiation target for a particle beam, and a method for producing a target nuclide using the same.

[0002] By irradiating a target material with a particle beam, it is possible to generate a target nuclide (atomic nucleus) through a nuclear reaction of the target nuclide contained in the target material. One of the target nuclides generated in this way is actinium-225 ( ２２５ Ac). ２２５ Ac is an alpha-ray emitting nuclide that is expected to be used in nuclear medicine therapy. In nuclear medicine therapy, a drug containing a radioisotope (RI) is selectively accumulated in the diseased area or lesion (cancer or benign disease area), and the radiation such as beta (β) rays and alpha (α) rays emitted from the RI kills the cells. ２２５ The demand for Ac is increasing rapidly.

[0003] ２２５ Ac is radioactive radium-226 ( ２２６ Ra) as a target substance, ２２６ It can be produced by the nuclear reaction of the following formula (1) which occurs when Ra is irradiated with a proton beam. ２２６ Ra + p → ２２５ Ac + 2n (1) where p is a proton and n is a neutron (see, for example, Patent Document 1).

[0004] Also, ２２５ Ac is ２２６ It can also be produced by the nuclear reaction of the following formula (2) that occurs when Ra is irradiated with a deuteron beam. ２２６ Ra + d → ２２５ Ac + 3n (2) where d is a deuteron and n is a neutron (see, for example, Patent Document 1).

[0005] Japanese Patent Application Laid-Open No. 2022-188190

[0006] but, ２２６ ​Ra is an extremely rare and expensive nuclide. When the target nuclide is rare, it is possible to efficiently generate the target nuclide by irradiating a small amount of target material containing the target nuclide with a particle beam having a narrow cross section. For example, it is possible to set the size of the target material and the cross section of the particle beam to a diameter of 3 mm or less when viewed from the irradiation direction of the particle beam.

[0007] It is necessary to confine the target material in a sealed space to prevent radioactive material from leaking outside. ２２６ Ra is naturally produced as the gaseous radionuclide radon-222 ( ２２２ In this case, radioactive material in gaseous state ２２２ It is necessary to keep Rn confined in a sealed space.

[0008] The present invention was made based on this new idea. That is, an object of the present invention is to make it possible to easily place even a small amount of target material at a predetermined location that will be the particle beam irradiation position in an enclosed space.

[0009] According to the present invention, there is provided a storage device for storing a target material that is an irradiation target of a particle beam, comprising: a target container having an internal space with an upward opening and a lower bottom surface; and a closure member attached to the target container so as to close the opening and seal the internal space, and through which the particle beam can pass, wherein the bottom surface includes a recess that is recessed downward, and the target material is placed in the recess.

[0010] According to the present invention, even a small amount of target material can be easily placed at a predetermined location in a sealed space where the particle beam will be irradiated.

[0011] 1A is a cross-sectional view of a storage device according to an embodiment of the present invention; FIG. 1B is a cross-sectional view taken along line 1B-1B in FIG. 1A; FIG. 2A is a partial enlarged view of FIG. 1, showing only the target container and the like; FIG. 2A is a view showing only the target container held in the recess of the target container; ２２６1A shows a jig for drying the Ra solution. It is a view taken along the arrows 3A-3A of FIG. 2A. It is a view taken along the arrows 3B-3B of FIG. 2B. It is a view taken along the arrows 4B-4B of FIG. 4A, which is a view showing only the first flow path member, the annular seal member, and the second closing member in FIG. 1A, but shows only the first flow path member. It is a view taken along the arrows 4C-4C of FIG. 4A. It is a schematic diagram showing a coolant circulation device. It is a view showing only the second flow path member in FIG. 1. It is a view taken along the arrows 6B-6B of FIG. 6A. It is a view taken along the arrows 6C-6C of FIG. 6A. It shows a state in which the storage device according to this embodiment is arranged in a predetermined position relative to the particle beam irradiation device. It is a view taken along the arrows VIII-VIII of FIG. 7, but shows only the beam aperture forming member. It is a partially enlarged view of FIG. 1, showing another example of a configuration showing only the target container and the like. It is a view taken along the arrows 9A-9C of FIG. 1A, showing yet another example of a configuration showing only the target container and the like. It is a partially enlarged view of FIG. 1, showing yet another example of a configuration showing only the target container and the like. It is a view taken along the arrows 9C-9C of FIG. Fig. 11A shows the configuration of a first connection device and a first supply pipe connection device according to a modified example. Fig. 11B shows a partial enlarged view of Fig. 1, showing another configuration example showing only the target container etc. Fig. 11C shows a partial enlarged view of Fig. 1, showing yet another configuration example showing only the target container etc. Fig. 11A shows a case where the shape of the depression is conical. Fig. 11B shows a case where the shape of the depression is conical.

[0012] An embodiment of the present invention will be described with reference to the drawings. In addition, common parts in each drawing are given the same reference numerals, and duplicated explanations will be omitted.

[0013] <Outline of Storage Device> Fig. 1A is a cross-sectional view showing a storage device 10 according to an embodiment of the present invention. Fig. 1B is a cross-sectional view taken along line 1B-1B in Fig. 1A. Note that Fig. 1A is a cross-sectional view taken along line 1A-1A in Fig. 1B. Fig. 2A is a partially enlarged view of Fig. 1, showing only the target container 3 and the like. Fig. 2B is a view showing only the target container 3 in Fig. 2A.

[0014] The storage device 10 is a device that stores a target material 1, which is an irradiation target of a particle beam, in a sealed manner from the outside. The storage device 10 is placed at a predetermined installation position on a beam path B (indicated by a dashed arrow in FIG. 1A etc.) through which a particle beam passes in the particle beam irradiation device. In this state, a particle beam generated by the particle beam irradiation device travels on the beam path B and is irradiated onto the target material 1 stored in the storage device 10. Note that in the present application, the target material 1 may be a solid or a liquid.

[0015] According to this embodiment, the target material 1 in the storage device 10 is irradiated with a particle beam from above (details will be described later). That is, the particle beam is irradiated with the target material 1 from above in a vertical direction or in a direction slightly inclined relative to the vertical direction.

[0016] The particle beam may be, for example, a charged particle beam. In this case, the charged particle beam may be accelerated (e.g., a proton beam) using an accelerator such as a cyclotron or a linac in a particle beam irradiation device. The particle beam may be irradiated onto the target material 1 in the storage device 10 with its cross section narrowed. For example, the cross-sectional dimension of the particle beam when irradiated onto the target material 1 may be 3 mm or less or 1 mm or less. Here, the cross-sectional dimension may be the maximum value of the dimensions in each direction perpendicular to the traveling direction of the particle beam, or the diameter if the cross section of the particle beam is circular.

[0017] The target material 1 contains a nuclide (hereinafter referred to as the target nuclide) that undergoes a nuclear reaction when the particle beam is irradiated onto the target material 1. The nuclear reaction of the target nuclide produces a target nuclide. In this embodiment, the target nuclide is radioactive radium-226 ( ２２６ Ra), and the target nuclide is actinium-225 ( ２２５ In this case, the particle beam may be, for example, a proton beam or a deuteron beam. However, according to the present invention, the target nuclide and the target nuclide are not limited to this combination. For example, when the target nuclide is ２２６ Ra, but the target nuclide may be other, and the target nuclide may be ２２６ It may be something other than Ra.

[0018] as a target nuclide ２２６ By irradiating Ra with a proton beam as a particle beam ２２５ The radioactivity A (Bq) of Ac can be calculated using the following formula (3). In formula (3), the symbols are as follows: A = NFσ(1-e －λｔ ) (3) N: per unit area ２２６ Ra atomic number [1 / cm ２ ] F: proton flux (beam intensity, current) [1 / s] σ: nuclear reaction cross section (nuclear reaction probability) [cm ２ ] λ: ２２５ Decay constant of Ac [1 / s] t: proton beam irradiation time [s]

[0019] Target substance 1 ２２６ Ra is a radioactive nuclide, and its handling is subject to strict regulations. It is also an extremely rare and expensive substance. ２２６ Ra emits alpha rays and produces the radionuclide radon-222 ( ２２２ Radon is a gas at room temperature, and in order to avoid internal exposure, it is necessary to prevent the gas from leaking. For this reason, it is important to use as little radon as possible. ２２６ Ra is the target nuclide, ２２５ In the manufacturing process of Ac ２２２ Complete containment of Rn is desirable.

[0020] Therefore, the storage device 10 according to this embodiment is configured to place a small amount of target material 1 in a location (recess D described below) in the internal space 3a of the sealed storage device 10 that is a predetermined irradiation position of the particle beam with a narrowed cross section.

[0021] 2A and 2B, the storage device 10 includes a target container 3 having an internal space 3a with an upward opening 3a1 and a downward bottom surface 3a2, and a closing member 5a that is attached to the target container 3 and is transmissive to a particle beam so as to close the opening 3a1 and seal the internal space 3a. The bottom surface 3a2 also includes a downwardly recessed depression D, in which a target material 1 is placed.

[0022] For example, the target material 1 can be placed in the storage device 10 as follows: The storage device 10 is transported to a sealed environment (e.g., the inside of a glove box), which is a work area sealed from the outside. In this sealed environment, with the opening 3a1 of the target container 3 open, the target material 1 is placed in the recess D on the bottom surface 3a2 of the internal space 3a. Then, by sealing the opening 3a1 with the first closing member 5a, a small amount of the target material 1 can be easily placed in the recess D, which corresponds to a predetermined particle beam irradiation position in the sealed internal space 3a. The storage device 10 is then removed from the sealed environment and placed in a predetermined installation position on the beam path B as described above.

[0023] In this state, a sharp particle beam with a small cross section is focused onto a small area (for example, an area of ​​10 mm as viewed vertically from above) placed in a small depression D. ２ This allows the amount of target nuclide required for producing the desired nuclide to be significantly reduced. ２２６ By irradiating Ra with a proton beam ２２５ When producing Ac, ２２５ Necessary for Ac production ２２６ The amount of Ra can be reduced by one order of magnitude. The area of ​​the opening of the recess D (i.e., the area of ​​the recess D as viewed vertically from above) is, for example, 10 mm ２ Below, 5mm ２ Below, 3mm ２ Less than or equal to 1 mm ２ It may be the following:

[0024] Furthermore, since the target material 1 only needs to be placed in the downward recess D, it is easy to place the target material 1 at a position where the particle beam will hit, and it is possible to stably hold the placed target material 1. For example, even if the solid target material 1 is melted by irradiation with the particle beam, the melted target material 1 can be stably held in the downward recess D.

[0025] For example, in the above-mentioned sealed environment (for example, a glove box), ２２６The solution of Ra is placed in the recess D in the target container 3 as the solution of the target substance 1, and the solution is simply dried. ２２６ A solid target material 1 containing Ra can be placed in the recess D. This drying may be performed by flowing a dry gas (e.g., dry helium gas, nitrogen gas, etc.) into the solution in the recess D. In this case, the drying may be performed using a drying device 80 (jig) as shown in FIG. 2C .

[0026] 2C shows an example of the configuration of a drying device (jig) 80. This drying device 80 includes a cover body 81 and a gas exhaust pipe 82. The drying device 80 may be used in the above-mentioned sealed environment.

[0027] The cover body 81 is removably attached to the target container 3 so as to surround the area above the opening 3a1 formed on the upper surface 3b of the target container 3. In this state (hereinafter referred to as the attached state), the cover body 81 may define a local airtight space 81a inside together with the upper surface 3b of the target container 3. The airtight space 81a is a space that is continuous upward from the internal space 3a of the target container 3 and its opening 3a1.

[0028] A gas inlet hole 81c and a gas outlet hole 81d are formed at different positions on the wall 81b of the cover body 81. The wall 81b has a side wall 81b1 surrounding the airtight space 81a and an upper wall 81b2 covering the airtight space 81a from above. The cover body 81 may be, for example, a cylindrical member whose upper end is closed by the upper wall 81b2 and whose lower end is open. However, other shapes may be used as long as the wall 81b (the side wall 81b1 and the upper wall 81b2) can form the airtight space 81a as described above. A sealing member (e.g., an O-ring, not shown) may be attached to the lower end of the side wall 81b1. The cover body 81 may be attached to the target container 3 by pressing the lower end of the side wall 81b1 of the cover body 81 against the upper surface 3b of the target container 3 by appropriate means to tightly seal the cover body 81 to the target container 3. This means is not shown, but may be, for example, a clamp that clamps the entire cover body 81 and the target container 3 from above and below (in the vertical direction in Figure 2C) so as to press the lower end of the side wall 81b1 against the upper surface 3b.

[0029] The dry gas described above is introduced into the airtight space 81a inside the cover body 81 from a gas supply source (not shown) outside the cover body 81 through the gas inlet hole 81c. A gas pipe fitting 83 may be attached to the gas inlet hole 81c. The tip of a gas inlet pipe 84 for introducing the dry gas may be connected to this gas pipe fitting 83. The dry gas from the gas supply source may be introduced into the airtight space 81a through the gas inlet pipe 84 and the inside of the gas pipe fitting 83 (i.e., the gas inlet hole 81c). Note that the gas pipe fitting 83 may be omitted, and the tip of the gas inlet pipe 84 may be airtightly attached to the gas inlet hole 81c.

[0030] The gas exhaust pipe 82 is attached to the cover body 81. The gas exhaust pipe 82 may pass through the gas exhaust hole 81d in an airtight manner or may be airtightly connected to the gas exhaust hole 81d. In the above-described attached state in which the cover body 81 is attached to the target container 3, the tip opening 82a of the gas exhaust pipe 82 is located in the internal space 3a of the target container 3 and faces the recess D in the vertical direction. In the example of FIG. 2C , the gas exhaust pipe 82 is attached to the cover body 81 so as to pass through the gas exhaust hole 81d in an airtight manner. In this case, the rear end of the gas exhaust pipe 82 is located outside the cover body 81. Alternatively, the rear end of the gas exhaust pipe 82 may be attached to a gas pipe fitting (not shown) attached to the gas exhaust hole 81d. As a result, the gas exhaust pipe 82 is airtightly connected to the gas exhaust hole 81d. In this case, the gas exhaust pipe 82 may be connected to another gas pipe arranged outside the cover body 81 via the gas pipe fitting. The gas exhaust pipe 82 may be a quartz pipe or a pipe made of other materials.

[0031] In this drying device 80 (jig), a dry gas is introduced into the airtight space 81 a through the gas inlet pipe 84 and the gas inlet hole 81 c. As shown by the dashed arrows indicating the flow of the dry gas in Fig. 2C , the dry gas introduced into the airtight space 81 a flows from above the upper surface 3 b of the target container 3 into the internal space 3 a below the upper surface 3 b, reaches the vicinity of the solution in the depression D, then flows into the gas exhaust pipe 82 from the tip opening 82 a of the gas exhaust pipe 82, passes through the gas exhaust pipe 82 and the gas exhaust hole 81 d, and flows to the outside of the cover body 81. Then, the dry gas is recovered through the gas exhaust pipe 82 or through the gas exhaust pipe 82 and the other gas pipe to a radon gas recovery device (not shown) outside the cover body 81. According to this flow of dry gas, the dry gas that has flowed near the solution flows into the gas exhaust pipe 82 from the tip opening 82a of the gas exhaust pipe 82 and is exhausted to the outside of the cover body 81 without reaching the upper surface 3b of the target container 3. This minimizes radioactive contamination of the upper surface 3b caused by radioactive substances in the solution in the recess D. The dry gas may be continuously introduced into the airtight space 81a through the gas inlet pipe 84 and the gas inlet hole 81c. In this case, the airtight space 81a may be suctioned by an appropriate suction device through the tip opening 82a of the gas exhaust pipe 82 and the gas exhaust pipe 82.

[0032] <Configuration of Target Vessel> The target vessel 3 may be made of a material having a higher melting point than the target material 1. For example, the material may be tantalum (Ta). In this case, the target material 1 contains tantalum (Ta) as a target nuclide. ２２６ Ra oxide ２２６ It may be RaO. ２２６ RaO is the heat generated by the irradiation of the target material 1 with the particle beam. ２２６ It may arise from Ra.

[0033] When the target vessel 3 is made of a material (for example, tantalum) that is difficult to dissolve in nitric acid or hydrochloric acid, the recess D in the target vessel 3 ２２６ The target material 1 containing Ra is irradiated with a particle beam as described above. ２２５ Ac is generated, and then nitric acid or hydrochloric acid is poured into the inner space 3 a of the target vessel 3 to dissolve the target material 1; ２２５ Ac can be chemically separated.

[0034] In the internal space 3a of the target container 3, a depression D may be formed in a part (for example, the center) of the bottom surface 3a2 facing upward. In this case, the bottom surface 3a2 may be a horizontal plane entirely except for the depression D. In this way, the target container 3 can be easily manufactured as long as the bottom surface 3a2 of the internal space 3a includes the depression D.

[0035] Target substance 1 ２２６ When Ra is contained, after the target material placed in the recess D is irradiated with the particle beam, the valuable material remaining in the recess D in the target container 3 is ２２６ Ra can be easily recovered with high efficiency.

[0036] Furthermore, when a small target vessel 3 is made of a material (e.g., tantalum) that is not easily dissolved in nitric acid or hydrochloric acid as described above, after the particle beam is irradiated onto the target material 1 placed in the recess D, the target vessel 3 can be placed in a beaker or the like and washed thoroughly with a small amount of acid.

[0037] Furthermore, when the target vessel 3 is covered with lead blocks to shield it from radiation from the radioactive nuclides inside the target vessel 3, since the target vessel 3 is small, only a small number of lead blocks can shield the radiation.

[0038] <Configuration for sealing the target container> Figure 3A is a view taken along the line 3A-3A in Figure 2A. Figure 3B is a view taken along the line 3B-3B in Figure 2B. The storage device 10 includes the first closing member 5a, the pressing member 7, and the annular sealing member 9 described above with respect to the target container 3.

[0039] The first closing member 5a may be attached to the upper surface 3b of the target container 3 so as to close the upward opening 3a1 (FIG. 2B) in the internal space 3a of the target container 3.

[0040] As described above, the first closing member 5 a is configured to be transmissive to the particle beam. In this embodiment, the first closing member 5 a is a sheet-shaped member (e.g., metal foil). In this case, the first closing member 5 a is formed of a material that is transmissive to the particle beam in its thickness direction. The material of the first closing member 5 a may be beryllium or a Harvar alloy (a cobalt-based alloy), but may also be other materials (e.g., metals such as Ti, Nb, Ta, Au, Pt, Ir, Ru, Rh, Pd, Al, Ag, Cu, Ni, Co, and Ti alloys, or graphite).

[0041] The thickness of the sheet-like first closing member 5a may be 1 μm or more and 1000 μm or less (for example, 1 μm or more and 100 μm or less, or 1 μm or more and 10 μm or less).

[0042] The pressing member 7 is attached to the target container 3 so as to cover the outer peripheral portion of the upper surface 5a1 of the first closing member 5a and press the first closing member 5a against the outer peripheral portion of the upper surface 5a1. When viewed from above, the pressing member 7 has a beam through-hole 7a formed therein so as to penetrate the pressing member 7 in the vertical direction in a range including the portion overlapping with the depression D.

[0043] Such a pressing member 7 may press the first closing member 5a against the upper surface 3b of the target container 3 over the entire circumference surrounding the opening 3a1 of the first closing member 5a. As a result, the first closing member 5a is sandwiched between the pressing member 7 and the upper surface 3b of the target container 3 over the entire circumference surrounding the opening 3a1. Note that the shape of the first closing member 5a when viewed from above may be circular as shown in FIG. 3A , but may also be other shapes.

[0044] The pressing member 7 is removably attached to the target container 3. For example, the pressing member 7 may be attached to the target container 3 with a fastening member 8 (bolt, screw, etc.). For example, as shown in FIGS. 2A and 2B , a threaded hole 3b2 may be provided on the top surface 3b of the target container 3, and a through-hole 7b ( FIG. 2A ) through which the fastening member 8 passes may be formed in the pressing member 7. The male threaded portion at the tip end of the fastening member 8 passed through the through-hole 7b may be threaded into the female thread of the threaded hole 3b2, thereby tightening the pressing member 7 to the top surface 3b of the target container 3 with the head 8a of the fastening member 8. The through-hole 7b may have a shape such that the head 8a of the fastening member 8 does not protrude upward from the top surface of the pressing member 7. That is, the through-hole 7b may have a lower portion and an upper portion having a cross-sectional area larger than that of the lower portion and into which the head 8a of the fastening member 8 is inserted. A plurality of such sets of fastening members 8, screw holes 3b2, and through holes 7b may be provided at different positions.

[0045] The annular sealing member 9 is provided to more reliably seal the gap between the first closing member 5a and the upper surface 3b of the target container 3. As shown in FIGS. 2B and 3B , an annular groove 3b1 in which the annular sealing member 9 is disposed is formed on the upper surface 3b of the target container 3 so as to surround the opening 3a1. When the annular sealing member 9 (the lower portion of the annular sealing member 9) is disposed in the annular groove 3b1, the annular sealing member 9, together with the first closing member 5a, is sandwiched between the pressing member 7 and the target container 3, thereby sealing the gap between the first closing member 5a and the upper surface 3b of the target container 3. The annular sealing member 9 may be formed from a heat-resistant material (e.g., rubber) that is capable of restoring its shape when deformed by an external force.

[0046] A plurality of such annular sealing members 9 may be provided. In the examples of Figures 2A and 3A, two annular sealing members 9a and 9b are provided as the annular sealing member 9. The plurality of annular sealing members 9a and 9b have different dimensions and are arranged at positions different distances from the inner opening 3a1. Furthermore, a plurality of annular grooves 3b1 in which the plurality of annular sealing members 9a and 9b are respectively arranged may be formed in the upper surface 3b of the target container 3. The plurality of annular sealing members 9a and 9b more reliably seal the gap between the first closing member 5a and the upper surface 3b of the target container 3.

[0047] According to this configuration, the target material 1 is placed in the recess D of the target container 3 in the sealed environment (glove box), and then the opening 3a1 of the target container 3 is closed with the first closing member 5a using the pressing member 7. In this state, the storage device 10 is transported to a predetermined installation position on the beam path B, and the target material 1 in the target container 3 can be irradiated with a particle beam. Thereafter, the storage device 10 can be transported back into the sealed environment, the opening 3a1 of the target container 3 can be opened, and a process such as recovery of the target nuclide in the target material 1 can be performed.

[0048] 1A and 1B , the storage device 10 includes a first flow path forming structure 11 that forms a first sealed flow path F1 through which a cooling medium M flows on the upper surface 3b of the first closing member 5a. The cooling medium M flowing through the first sealed flow path F1 may be a cooling gas. One example of the gas is helium gas, but the gas is not limited to this.

[0049] The first sealed flow path F1 is entirely airtight (or liquidtight) from the outside, except for both ends of the first sealed flow path F1 connected to a supply pipe 16 and a recovery pipe 26, which will be described later. The both ends of the first sealed flow path F1 are shut off from the outside by first and second shutoff valves 18 and 28, which will be described later, respectively, so that the entire first sealed flow path F1 is sealed from the outside.

[0050] In the first flow path forming structure 11, a beam through hole 12a that penetrates in the vertical direction is formed in a portion that overlaps the first sealed flow path F1 and the recess D when viewed from above.

[0051] The first flow path forming structure 11 includes a second closing member 5b that closes the beam through hole 12a to seal the first sealed flow path F1 from above. The second closing member 5b is configured to be transparent to the particle beam. The configuration (shape, material, and thickness) of the second closing member 5b is the same as that of the first closing member 5a. Note that the second closing member 5b may be pressed against the first flow path forming structure 11 (the first flow path member 12 in the illustrated example) by, for example, a second flow path member 32, as described below.

[0052] 1A and 1B, the first flow path forming structure 11 has a first flow path member 12, first and second closing members 5a and 5b, and a pressing member 7. Seal members (e.g., annular seal members) not shown may be provided as appropriate between the multiple members that make up the storage device 10. This may allow the first sealed flow path F1 (and a second sealed flow path F2, described below) to be airtightly (or liquidtightly) sealed from the outside of the storage device 10.

[0053] Fig. 4A is a diagram showing only the first flow path member 12, the annular seal member 14 described below, and the second closing member 5b in Fig. 1A. Fig. 4B is a view taken along the arrows 4B-4B in Fig. 4A, but the annular seal member 14 and the second closing member 5b are omitted from the illustration. Fig. 4C is a view taken along the arrows 4C-4C in Fig. 4A. Fig. 4A is a cross-sectional view taken along the line 4A-4A in Fig. 4B.

[0054] The above-mentioned beam through hole 12a penetrates the center of the first flow path member 12 in the vertical direction. The second closure member 5b is attached to the upper surface 12e of the first flow path member 12 so as to close the beam through hole 12a and seal the first sealed flow path F1. As will be described later, the second closure member 5b may be pressed against the upper surface 12e of the first flow path member 12 by the second flow path member 32, and attached to the first flow path member 12 in this state.

[0055] As shown in FIGS. 1B and 4B , the first sealed flow path F1 may extend (e.g., linearly) through the first flow path forming structure 11 in a direction intersecting (e.g., perpendicular to) the vertical beam path B (hereinafter simply referred to as the intersecting direction). In this case, the first sealed flow path F1 includes the beam through hole 12a and two flow path holes 12b and 12c communicating with the beam through hole 12a. As shown in FIG. 4B , each of the flow path holes 12b and 12c has an opening 12b1 or 12c1 on the side surface of the first flow path member 12 and extends from the opening 12b1 or 12c1 to the beam through hole 12a (e.g., linearly in the intersecting direction). The two flow path holes 12b and 12c are formed at different positions (e.g., on opposite sides of the beam through hole 12a).

[0056] 4A and 4C, a fitting hole 12d is formed on the lower surface of the first flow path member 12. As shown in FIG. 1A, the pressing member 7 and an upper portion (e.g., the upper end) of the target container 3 are removably fitted into the fitting hole 12d. In this state, the bottom surface of the fitting hole 12d may be in close contact with the upper surface of the pressing member 7. The first flow path member 12 may be attached to the target container 3 by being coupled to a third flow path member 61 described below.

[0057] 4C, when viewed from below, the flow path holes 12b and 12c have an opening downward (toward the fitting hole 12d) at the portion that overlaps with the fitting hole 12d. The opening is closed by the upper surface of the pressing member 7 inserted into the fitting hole 12d.

[0058] As described above, the first flow path forming structure 11 forms a first sealed flow path F1 through which the cooling medium M flows on the upper surface 5a1 of the first closing member 5a, so that the first closing member 5a through which the particle beam passes can be directly cooled by the cooling medium M.

[0059] <Connection Structure Between First Sealed Flow Path and Cooling Medium Circulation Device> A cooling medium M (e.g., helium gas) circulated by the cooling medium circulation device 100 flows through the first sealed flow path F1. FIG. 5 is a schematic diagram showing the cooling medium circulation device 100. The cooling medium circulation device 100 includes a supply pipe 16 and a recovery pipe 26 connected to both ends of the first sealed flow path F1, respectively, to form a circulation flow path Fc including the first sealed flow path F1, the supply pipe 16, and the recovery pipe 26. The circulation flow path Fc is sealed from the outside. The cooling medium M flows through the circulation flow path Fc so as to circulate. Note that although the cooling medium circulation device 100 is not a component of the storage device 10 in this embodiment, it may be a component of the storage device 10 according to the present invention.

[0060] 5, the circulation flow path Fc includes a branching point and a merging point with respect to the second sealed flow path F2, as will be described later. The supply pipe 16 extends from the branching point of the circulation flow path Fc to a connecting point with the first sealed flow path F1, and the recovery pipe 26 extends from the connecting point with the first sealed flow path F1 to the merging point with the circulation flow path Fc.

[0061] The cooling medium circulation device 100 may include a pressure-feeding device 101 (e.g., a compressor) and a heat exchanger 102 provided in the circulation flow path Fc. The pressure-feeding device 101 pressure-feeds the cooling medium M to the supply pipe 16. The heat exchanger 102 indirectly cools the cooling medium M flowing through the circulation flow path Fc.

[0062] The entire circulation flow path Fc may be filled with the cooling medium M by any suitable method. For example, a vacuum pump and a cooling medium source may be connected to the circulation flow path Fc at different locations (locations other than the first and second sealed flow paths F1 and F2) via respective on-off valves, and the gas in the circulation flow path Fc may be evacuated by the vacuum pump to create a vacuum within the circulation flow path Fc, and then the evacuated circulation flow path Fc may be filled with the cooling medium M from the cooling medium source.

[0063] 1B , the storage device 10 includes first and second connecting devices C1 and C2 for detachably connecting both ends of the first sealed flow path F1 to the supply pipe 16 and the recovery pipe 26 of the cooling medium circulation device 100, respectively. The first connecting device C1 is attached to one end (first flow path forming structure 11) of the first sealed flow path F1, and is capable of connecting the supply pipe 16 of the cooling medium M to the first sealed flow path F1, forming a passage region R1 through which the cooling medium M from the supply pipe 16 flows to the first sealed flow path F1. The second connecting device C2 is attached to the other end (first flow path forming structure 11) of the first sealed flow path F1, and is capable of connecting the recovery pipe 26 of the cooling medium M to the first sealed flow path F1, forming a passage region R2 through which the cooling medium M flows from the first sealed flow path F1 to the recovery pipe 26.

[0064] The first connection device C1 has a first joint 15 that can be connected to and disconnected from a supply pipe 16. The first joint 15 may be provided at one end of the first sealed flow path F1, as in the example of FIG. 1B . In this case, the first joint 15 is airtightly (or liquid-tightly) attached to the first flow path forming structure 11 (the first flow path member 12 in the example of FIG. 1A ). The first joint 15 is configured to be connectable to a supply pipe 16 that supplies a cooling medium M to the first sealed flow path F1. With the first joint 15 connected to the supply pipe 16, the cooling medium M can flow from the supply pipe 16 through the first joint 15 into the first sealed flow path F1.

[0065] Meanwhile, a first supply pipe connection device Cs1 is attached to one end of the supply pipe 16. The first supply pipe connection device Cs1 is connectable to the first fitting 15 and forms a passage area Rs1 through which the cooling medium M from the supply pipe 16 flows to the first connection device C1. The first supply pipe connection device Cs1 has a supply pipe fitting 17 that can be connected to and disconnected from the first fitting 15. The supply pipe fitting 17 may constitute one end of the supply pipe 16. For example, a nut N is attached to the outer periphery of the first fitting 15 so as to be movable within a predetermined range in the axial direction. The nut N may be threaded onto a male thread formed on the outer periphery of the supply pipe fitting 17 and tightened to couple the first fitting 15 and the supply pipe fitting 17. Furthermore, the nut N can be rotated in a loosening direction from this state to remove the first fitting 15 from the supply pipe fitting 17. However, the first joint 15 may be removably coupled to the supply pipe joint 17 in other configurations. The nut N may be a component of the first joint 15.

[0066] The second connection device C2 has a second joint 25 that can be connected to and disconnected from the recovery pipe 26. The second joint 25 may be provided at the other end of the first sealed flow path F1, as in the example of FIG. 1B . In this case, the second joint 25 is airtightly (or liquid-tightly) attached to the first flow path forming structure 11 (the first flow path member 12 in the example of FIG. 1A ). The second joint 25 is configured to be connectable to the recovery pipe 26 that recovers the cooling medium M that has flowed through the first sealed flow path F1. With the second joint 25 connected to the recovery pipe 26, the cooling medium M can flow from the first sealed flow path F1 into the recovery pipe 26 through the second joint 25.

[0067] Meanwhile, a first recovery pipe connection device Cr1 is attached to one end of the recovery pipe 26. The first recovery pipe connection device Cr1 is connectable to the second joint 25 and forms a passage area Rr1 through which the cooling medium from the second joint device C2 flows into the recovery pipe 26. The first recovery pipe connection device Cr1 has a recovery pipe joint 27 that can be connected to and disconnected from the second joint 25. The recovery pipe joint 27 may constitute one end of the recovery pipe 26. For example, a nut N is attached to the outer periphery of the second joint 25 so as to be movable within a predetermined range in its axial direction. The second joint 25 and the recovery pipe joint 27 may be coupled by threading and tightening this nut N onto a male thread formed on the outer periphery of the recovery pipe joint 27. However, the second joint 25 may be detachably coupled to the recovery pipe joint 27 in other configurations. The nut N may be a component of the second joint 25 .

[0068] With the storage device 10 placed at a predetermined installation position on the beam path B, the first and second joints 15, 25 are connected to the supply pipe joint 17 and the recovery pipe joint 27, respectively. This forms a circulation flow path Fc consisting of the supply pipe 16, the first sealed flow path F1, the recovery pipe 26, and other parts of the cooling medium circulation device 100. As described above, the interior of this circulation flow path Fc is sealed from the outside. The cooling medium circulation device 100 circulates the cooling medium M through this circulation flow path Fc. As a result, the cooling medium M is supplied from the supply pipe 16 to the first sealed flow path F1, the cooling medium M that has flowed through the first sealed flow path F1 flows into the recovery pipe 26, and the cooling medium M that has flowed into the recovery pipe 26 is again supplied from the supply pipe 16 to the first sealed flow path F1. In this manner, the cooling medium M can be circulated.

[0069] In this state, the particle beam irradiation device described above irradiates the particle beam onto the target material 1 in the storage device 10. At this time, the first closing member 5a, through which the particle beam passes, generates heat, but the first closing member 5a can be directly cooled by the cooling medium M flowing in the first sealed flow path F1.

[0070] Furthermore, the target nuclide contained in the target material 1 (e.g. ２２６ Ra) spontaneously decays into gaseous radionuclides (e.g. ２２２Rn), even if the gaseous radionuclide generated in the internal space 3a of the target container 3 leaks to the upper surface 5a1 side of the first closing member 5a, the upper surface 5a1 side is the first sealed flow path F1. Therefore, even if the gaseous radionuclide leaks to the upper surface 5a1 side of the first closing member 5a, the gaseous radionuclide can be contained within the first sealed flow path F1.

[0071] <Blocking structure for both ends of first sealed flow path> In order to block both ends of the first sealed flow path F1 from the outside when the both ends of the first sealed flow path F1 are removed from the supply pipe 16 and the recovery pipe 26, respectively, the first and second connecting devices C1 and C2 are provided with first and second shut-off valves 18 and 28, respectively, as shown in FIG. 1B.

[0072] The first shut-off valve 18 can open and close the above-mentioned passage region R1. That is, the first shut-off valve 18 can be switched between an open position where the cooling medium M can pass through the first passage region R1 (first joint 15) of the first connecting device C1 and a closed position where the cooling medium M cannot pass through the first passage region R1. In the example of FIG. 1B , the passage region R1 is an internal region of the first joint 15, and the first shut-off valve 18 is provided in the first joint 15.

[0073] 1B , the first shutoff valve 18 is provided inside the first joint 15. When the supply pipe joint 17 is connected to the first joint 15, the first shutoff valve 18 is automatically or manually operated to the open position. In one example, the first shutoff valve 18 is operated from the closed position to the open position by being pressed by a member on the supply pipe joint 17 side connected to the first joint 15 (for example, a tip end portion Va of a valve body V of a supply-side shutoff valve 19 described below), and is maintained in the open position.

[0074] Furthermore, the first shutoff valve 18 is automatically or manually operated to the closed position when the supply pipe fitting 17 is removed from the first fitting 15. In one example, when the supply pipe fitting 17 is removed from the first fitting 15, the first shutoff valve 18 (e.g., valve body V described below) is operated to the closed position by the elastic restoring force of an elastic member (e.g., elastic member E described below) provided in the first shutoff valve 18, and is maintained in the closed position.

[0075] The first shutoff valve 18 may include, for example, a valve body V and an elastic member E (e.g., a coil spring). The valve body V is movable between the open position and the closed position. The elastic member E applies an elastic restoring force to the valve body V so as to maintain the valve body V in the closed position.

[0076] The second shutoff valve 28 can open and close the above-mentioned passage region R2. That is, the second shutoff valve 28 can be switched between an open position where the cooling medium M can pass through the passage region R2 (second joint 25) of the second connecting device C2 and a closed position where the cooling medium M cannot pass through the passage region R2. In the example of FIG. 1B , the passage region R2 is an internal region of the second joint 25, and the second shutoff valve 28 is provided in the second joint 25.

[0077] 1B , the second shutoff valve 28 is provided inside the second joint 25. When the recovery pipe joint 27 is connected to the second joint 25, the second shutoff valve 28 is automatically or manually operated to the open position. In one example, the second shutoff valve 28 (e.g., its valve body V) is pressed by a member of the second joint 25 connected to the recovery pipe joint 27 (in one example, the tip portion Va of the valve body V), thereby being operated from the closed position to the open position and maintained in the open position.

[0078] Furthermore, the second shutoff valve is automatically or manually operated to the closed position when the recovery pipe joint 27 is removed from the second joint 25. In one example, when the recovery pipe joint 27 is removed from the second joint 25, the second shutoff valve 28 (e.g., its valve body V) is operated to the closed position by the elastic restoring force of an elastic member (e.g., elastic member E) provided in the second shutoff valve 28, and is maintained in the closed position.

[0079] The second shutoff valve 28 may have, for example, a valve body V and an elastic member E (e.g., a coil spring) similar to the first shutoff valve 18. The configuration and function of the valve body V and elastic member E of the second shutoff valve 28 may be the same as those of the valve body V and elastic member E of the first shutoff valve 18, and therefore a description thereof will be omitted.

[0080] When the target nuclide in the target material 1 spontaneously radioactively decays to become a gaseous radionuclide at room temperature, even if the gaseous radionuclide generated in the internal space 3a of the target container 3 leaks into the first sealed flow path F1 on the upper surface 5a1 side of the first closing member 5a, both ends of the first sealed flow path F1 can be closed by the first and second shut-off valves 18, 28 after the target material 1 in the target container 3 is irradiated with the particle beam. Therefore, in this state, the storage device 10 can be transported from a position on the beam path B into, for example, the above-mentioned sealed environment (glove box). Therefore, leakage of the gaseous radionuclide to the outside can be reliably prevented even during transportation.

[0081] <Supply Pipe and Recovery Pipe Shutoff Structure> In order to shut off the circulation flow path Fc other than the first sealed flow path F1 from the outside when both ends of the first sealed flow path F1 are detached from the supply pipe 16 and the recovery pipe 26, the first supply pipe connection device Cs1 and the first recovery pipe connection device Cr1 are respectively provided with a supply-side shutoff valve 19 and a recovery-side shutoff valve 29 shown in FIG. 1B . The first supply pipe connection device Cs1 and the first recovery pipe connection device Cr1 may be components of the coolant circulation device 100.

[0082] The supply-side shutoff valve 19 can open and close the above-mentioned passage region Rs1. That is, the supply-side shutoff valve 19 can be switched between an open position where the cooling medium M can pass through the passage region Rs1 (supply pipe joint 17) of the first supply pipe connection device Cs1 and a closed position where the cooling medium M cannot pass through the passage region Rs1. In the example of FIG. 1B , the passage region Rs1 is an internal region of the supply pipe joint 17, and the supply-side shutoff valve 19 is provided in the supply pipe joint 17.

[0083] 1B, the supply-side shutoff valve 19 is provided inside the supply pipe joint 17. When the supply pipe joint 17 is connected to the first joint 15, the supply-side shutoff valve 19 is automatically or manually operated to the open position.

[0084] When the supply pipe joint 17 is removed from the first joint 15, the supply-side shutoff valve 19 is automatically or manually operated to the closed position.

[0085] The configuration and function of the supply-side shutoff valve 19 may be the same as the configuration and function of the first shutoff valve 18. For example, when the supply pipe fitting 17 is connected to the first fitting 15, the supply-side shutoff valve 19 (e.g., its valve element V) may be moved from the closed position to the open position and maintained at the open position by being pressed by a member of the first fitting 15 (the tip portion Va of the valve element V). Also, when the supply pipe fitting 17 is removed from the first fitting 15, the valve element V of the supply-side shutoff valve 19 may be moved to the closed position and maintained at the closed position by the elastic restoring force of an elastic member E provided in the supply-side shutoff valve 19.

[0086] The recovery-side shutoff valve 29 can open and close the above-mentioned passage region Rr1. That is, the recovery-side shutoff valve 29 can be switched between an open position where the cooling medium M can pass through the passage region Rr1 (recovery pipe joint 27) of the first recovery pipe connection device Cr1 and a closed position where the cooling medium M cannot pass through the passage region Rr1. In the example of FIG. 1B , the passage region Rr1 is an internal region of the recovery pipe joint 27, and the recovery-side shutoff valve 29 is provided in the recovery pipe joint 27.

[0087] 1B, the recovery-side shutoff valve 29 is provided inside the recovery pipe joint 27. Once the recovery pipe joint 27 is connected to the second joint 25, the recovery-side shutoff valve 29 is automatically or manually operated to the open position.

[0088] When the recovery pipe joint 27 is removed from the second joint 25, the recovery side shutoff valve 29 is automatically or manually operated to the closed position.

[0089] The configuration and function of the recovery-side shutoff valve 29 may be the same as the configuration and function of the second shutoff valve 28. For example, when the recovery pipe joint 27 is connected to the second joint 25, the valve element V of the recovery-side shutoff valve 29 may be moved from the closed position to the open position by being pressed by a member of the second joint 25 (the tip portion Va of the valve element V), and may be maintained at the open position. Furthermore, when the recovery pipe joint 27 is detached from the second joint 25, the valve element V of the recovery-side shutoff valve 29 may be moved to the closed position by the elastic restoring force of an elastic member E provided in the recovery-side shutoff valve 29, and may be maintained at the closed position.

[0090] As described above, even if the gaseous radionuclides generated in the internal space 3a of the target container 3 leak into the circulation flow path Fc including the first sealed flow path F1 on the upper surface 5a1 side of the first closing member 5a, after the target material 1 in the target container 3 is irradiated with a particle beam, the flow path portion (including the supply pipe 16 and the recovery pipe) of the circulation flow path Fc other than the first sealed flow path F1 can be closed by the supply-side shutoff valve 19 and the recovery-side shutoff valve 29. Therefore, for example, if the gaseous radionuclides ２２２ In the case of Rn, if the flow path portion is left for one month in a state where it is blocked from the outside, ２２２ The radioactivity of Rn is reduced to 1 / 1000. ２２２ Rn is ２２２ It can also be disposed of through an Rn trap (activated charcoal trap at -100°C).

[0091] <Structure for forming a second sealed flow path> The storage device 10 includes a second flow path forming structure 31 that forms a second sealed flow path F2 on the upper surface of the second closing member 5b through which the cooling medium M flows. The cooling medium M flowing through the second sealed flow path F2 may be the same as the cooling medium M flowing through the first sealed flow path F1 (e.g., helium gas).

[0092] The entire second sealed flow path F2, except for both ends of the second sealed flow path F2 connected to a supply pipe 46 and a recovery pipe 56 (described later), is made airtight (or liquidtight) from the outside by the second flow path forming structure 31. The both ends of the second sealed flow path F2 are shut off from the outside by third and fourth shut-off valves 48 and 58 (described later), respectively, so that the entire second sealed flow path F2 is sealed from the outside.

[0093] In the second flow path forming structure 31, when viewed from above, a beam through hole 31a penetrating in the vertical direction is formed in a portion where the first and second sealed flow paths F1, F2 overlap with the recess D. In the example of Fig. 1A, this beam through hole 31a consists of beam through holes 32a, 33a, and 35a, which will be described later.

[0094] The second flow path forming structure 31 includes a third closing member 5c that closes the beam through hole 31a of the second flow path forming structure 31 so as to seal the second sealed flow path F2 from above. The third closing member 5c is configured to be transmissive to the particle beam. The configuration (shape, material, and thickness) of the third closing member 5c is the same as that of the first closing member 5a.

[0095] In the example of FIGS. 1A and 1B, the second flow path forming structure 31 has a second flow path member 32, a cover member 33, a pressing member 35, and second and third closing members 5b and 5c.

[0096] The above-mentioned beam through holes 32a, 33a, 35a extend vertically through the centers of the second flow path member 32, the cover member 33, and the pressing member 35. As will be described later, the third closing member 5c is disposed between the cover member 33 and the pressing member 35 so as to close the beam through hole 31a.

[0097] Fig. 6A is a view showing only the second flow path member 32 in Fig. 1. Fig. 6B is a view taken along the line 6B-6B in Fig. 6A. Fig. 6C is a view taken along the line 6C-6C in Fig. 6A.

[0098] 6A and 6B , the second sealed flow path F2 may extend (e.g., linearly) through the second flow path forming structure 31 in a direction intersecting (e.g., perpendicular to) the beam path B. In this case, when viewed from above, the second sealed flow path F2 may extend so as to intersect with the first sealed flow path F1. That is, when viewed from above, the first and second sealed flow paths F1 and F2 may extend (e.g., linearly) so as to intersect (e.g., perpendicular to) each other at the position of the beam path B.

[0099] The above-described second closing member 5b may be sandwiched between the second flow path member 32 and the first flow path member 12. For example, the second flow path member 32 may press the second closing member 5b against the upper surface 12e of the first flow path member 12 over the entire circumference surrounding the through hole 31a (32a) in the second closing member 5b.

[0100] The second flow path member 32 may be attached to the first flow path member 12 by fastening it to the upper surface 12e of the first flow path member 12 with fastening members (bolts, screws, etc.) not shown. The configuration of the fastening members may be similar to that of the fastening member 8 described above. For example, as shown in FIGS. 6B and 6C , a downward fitting hole 32d is formed in the upper surface 32e of the second flow path member 32, and a plurality of through holes 32g through which the fastening members pass are formed in the bottom surface 32d1 of the fitting hole 32d. As shown in FIG. 4B , threaded holes 12e2 into which the fastening members are threaded are formed in the upper surface 12e of the first flow path member 12 at positions aligned with the through holes 32g. The male threads at the tip of the fastening members passed through each through hole 32g may be threaded into the corresponding threaded holes 12e2 and tightened, thereby sandwiching the second flow path member 32 between the heads of the rear ends of the fastening members and the first flow path member 12.

[0101] An annular seal member 14 is provided to more reliably seal the gap between the second closing member 5b and the upper surface 12e of the first flow path member 12. The annular seal member 14, together with the second closing member 5b, is sandwiched between the second flow path member 32 and the first flow path member 12. Like the above-described annular seal member 9, the annular seal member 14 may be formed from a material (e.g., rubber) that is heat resistant and has the ability to restore its shape when deformed by an external force.

[0102] With regard to the annular seal member 14, an annular groove 12e1 (FIG. 4B) may be formed so as to surround the beam through hole 12a on the upper surface 12e of the first flow path member 12. The annular seal member 14 is disposed in this annular groove 12e1.

[0103] The second sealed flow path F2 includes the beam through hole 32a, two flow path holes 32b and 32c communicating with the beam through hole 32a, and two grooves 32f. The beam through hole 32a, the flow path holes 32b and 32c, and the grooves 32f are formed in the second flow path member 32. Each of the flow path holes 32b and 32c has an opening 32b1 or 32c1 on the side surface of the second flow path member 32 and extends (e.g., linearly) from the opening 32b1 or 32c1 to the groove 32f. The two flow path holes 32b and 32c are formed in different positions (e.g., on opposite sides of the beam through hole 32a). Each groove 32f is formed in the bottom surface 32d1 of the fitting hole 32d of the second flow path member 32 so as to communicate between the beam through hole 32a and the flow path hole 32b or 32c.

[0104] A protrusion 33b that protrudes downward is formed in the center of the underside of the cover member 33. As shown in Fig. 1A, the protrusion 33b fits into the fitting hole 32d from above. The protrusion 33b and the fitting hole 32d have shapes that match each other (for example, the same circular shape when viewed from above). A beam through-hole 33a is opened in the underside of the protrusion 33b.

[0105] 1A, the third closing member 5c may be sandwiched between the lower surface of the protruding portion 33b of the cover member 33 and the pressing member 35. For example, the pressing member 35 may press the third closing member 5c against the lower surface of the protruding portion 33b over the entire circumference surrounding the beam through hole 33a in the third closing member 5c when viewed from above.

[0106] The pressing member 35 may be attached to the protruding portion 33b by being fastened to the underside of the protruding portion 33b with a fastening member (bolt, screw, etc.) (not shown). The configuration of the fastening member may be the same as that of the fastening member 8 described above.

[0107] An annular seal member 37 may also be provided. The annular seal member 37, together with the third closing member 5c, is sandwiched between the lower surface of the protruding portion 33b of the cover member 33 and the pressing member 35. Similar to the above-described annular seal member 9, the annular seal member 37 may be formed from a material (e.g., rubber) that is heat resistant and exhibits the ability to restore its shape when deformed by an external force.

[0108] With regard to the annular seal member 37, an annular groove 33b1 (FIG. 1A) may be formed so as to surround the beam through hole 33a on the lower surface of the protruding portion 33b of the cover member 33. The annular seal member 37 may be disposed in this annular groove 33b1.

[0109] The lower surface of the pressing member 35 may come into close contact with the bottom surface 32d1 of the fitting hole 32d of the second flow path member 32, and close the upward opening of the groove 32f formed in the bottom surface 32d1.

[0110] As described above, the second flow path forming structure 31 forms a second sealed flow path F2 through which the cooling medium M flows on the upper surface of the second closing member 5b, so that the second closing member 5b through which the particle beam passes can be directly cooled by the cooling medium M.

[0111] Furthermore, even if the gaseous radionuclides generated in the internal space 3a of the target container 3 as described above leak into the first sealed flow path F1 on the upper surface 12e side of the first closing member 5a and further leak into the second sealed flow path F2 on the upper surface side of the second closing member 5b, the upper surface side is the second sealed flow path F2. Therefore, even if the gaseous radionuclides leak to the upper surface side of the second closing member 5b, the gaseous radionuclides can be contained within the second sealed flow path F2. Furthermore, by providing the first to third closing members 5a, 5b, and 5c, leakage of the gaseous radionuclides to the outside can be prevented in a triple manner.

[0112] <Connection Structure Between Second Sealed Flow Path and Cooling Medium Circulation Device> As with the first sealed flow path F1, the second sealed flow path F2 is configured to allow a circulating cooling medium M (e.g., helium gas) to flow therethrough by the cooling medium circulation device 100. While the cooling medium circulation device 100 is not a component of the storage device 10 in this embodiment, it may be a component of the storage device 10 according to the present invention. Furthermore, the cooling medium circulation device 100 may also serve as the above-described cooling medium circulation device 100 that causes the cooling medium M to flow through the first sealed flow path F1. That is, as shown in FIG. 5 , the above-described cooling medium circulation device 100 further includes a supply pipe 46 and a recovery pipe 56 connected to both ends of the second sealed flow path F2, respectively, to form a circulation flow path Fc including the second sealed flow path F2, the supply pipe 46, and the recovery pipe 56.

[0113] 5 , the circulation flow path Fc may branch into two flow path portions at a branching point, and then the two branched flow path portions may join at a joining point. One of the two flow path portions comprises the supply pipe 16, the first sealed flow path F1, and the recovery pipe 26, and the other comprises the supply pipe 46, the second sealed flow path F2, and the recovery pipe 56.

[0114] The circulation flow path Fc including the first sealed flow path F1 and the circulation flow path Fc including the second sealed flow path F2 may be formed independently of each other. In this case, a cooling medium circulation device 100 including a supply pipe 16 or 46, a recovery pipe 26 or 56, a pumping device 101, a heat exchanger 102, etc. may be provided for each of the first and second sealed flow paths F1 and F2.

[0115] 1A , the storage device 10 includes third and fourth connecting devices C3 and C4 for detachably connecting both ends of the second sealed flow path F2 to the supply pipe 46 and the recovery pipe 56 of the cooling medium circulation device 100, respectively. The third connecting device C3 is attached to one end of the second sealed flow path F2 (second flow path forming structure 31), is capable of connecting the supply pipe 46 of the cooling medium M to the second sealed flow path F2, and forms a passing region R3 through which the cooling medium M from the supply pipe 46 flows to the second sealed flow path F2. The fourth connecting device C4 is attached to the other end of the second sealed flow path F2 (second flow path forming structure 31), and is capable of connecting the recovery pipe 56 of the cooling medium M to the second sealed flow path F2, and forms a passing region R4 through which the cooling medium M flows from the second sealed flow path F2 to the recovery pipe 56.

[0116] The third connection device C3 has a third joint 45 that can be connected to and disconnected from the supply pipe 46. The third joint 45 may be provided at one end of the second sealed flow path F2, as in the example of FIG. 1A . In this case, the third joint 45 is airtightly (or liquid-tightly) attached to the second flow path forming structure 31 (the second flow path member 32 in the example of FIG. 1A ). The third joint 45 is configured to be connectable to the supply pipe 46 that supplies the cooling medium M to the second sealed flow path F2. With the third joint 45 connected to the supply pipe 46, the cooling medium M can flow from the supply pipe 46 through the third joint 45 into the second sealed flow path F2.

[0117] Meanwhile, a second supply pipe connection device Cs2 is attached to one end of the supply pipe 46. The second supply pipe connection device Cs2 is connectable to the third joint 45 and forms a passage region Rs2 through which the cooling medium M from the supply pipe 46 flows to the third connection device C3. The second supply pipe connection device Cs2 has a supply pipe joint 47 that can be connected to and disconnected from the third joint 45. The supply pipe joint 47 may constitute one end of the supply pipe 46.

[0118] The fourth connection device C4 has a fourth joint 55 that can be connected to and disconnected from the recovery pipe 56. The fourth joint 55 may be provided at the other end of the second sealed flow path F2, as in the example of FIG. 1A . In this case, the fourth joint 55 is airtightly (or liquid-tightly) attached to the second flow path forming structure 31 (the second flow path member 32 in the example of FIG. 1A ). The fourth joint 55 is configured to be connectable to the recovery pipe 56 that recovers the cooling medium M that has flowed through the second sealed flow path F2. With the fourth joint 55 connected to the recovery pipe 56, the cooling medium M can flow from the second sealed flow path F2 into the recovery pipe 56 through the fourth joint 55.

[0119] Meanwhile, a second recovery pipe connection device Cr2 is attached to one end of the recovery pipe 56. The second recovery pipe connection device Cr2 is connectable to the fourth joint 55 and forms a passage region Rr2 through which the cooling medium M from the fourth connection device C4 flows into the recovery pipe 56. The second recovery pipe connection device Cr2 has a recovery pipe joint 57 that can be connected to and disconnected from the fourth joint 55. The recovery pipe joint 57 may constitute one end of the recovery pipe 56.

[0120] The configurations and functions of the third fitting 45, the fourth fitting 55, the supply pipe fitting 47, and the recovery pipe fitting 57 may be the same as the configurations and functions of the first fitting 15, the second fitting 25, the supply pipe fitting 17, and the recovery pipe fitting 27 described above with respect to the first sealed flow path F1, respectively.

[0121] With the storage device 10 placed at a predetermined installation position on the beam path, the third and fourth joints 45, 55 are connected to the supply pipe joint 47 and the recovery pipe joint 57, respectively. This forms a circulation flow path Fc consisting of the supply pipe 46, the second sealed flow path F2, the recovery pipe 56, and other parts of the cooling medium circulation device 100. The interior of this circulation flow path Fc is sealed from the outside. The cooling medium circulation device 100 circulates the cooling medium M through this circulation flow path Fc. As a result, the cooling medium M is supplied from the supply pipe 46 to the second sealed flow path F2, the cooling medium M that has flowed through the second sealed flow path F2 flows into the recovery pipe 56, and the cooling medium M that has flowed into the recovery pipe 56 is again supplied from the supply pipe 46 to the second sealed flow path F2. In this manner, the cooling medium M can be circulated.

[0122] As described above, even if the gaseous radionuclides generated in the internal space 3a of the target container 3 leak into the first sealed flow path F1 on the upper surface 12e side of the first closing member 5a and further leak into the second sealed flow path F2 on the upper surface 32e side of the second closing member 5b, the gaseous radionuclides can be contained within the first and second sealed flow paths F1 and F2.

[0123] Furthermore, in this embodiment, portions of the first and second joints 15, 25 and portions of the third and fourth joints 45, 55 are located on the same imaginary horizontal plane. This allows the vertical dimension of the storage device 10 to be reduced. In this case, when viewed from above, the first and second sealed flow paths F1, F2 extend so as to intersect (e.g., perpendicular to) each other at positions overlapping with the recess D, thereby preventing the first and second joints 15, 25 and the third and fourth joints 45, 55 from interfering with each other. In other words, when viewed from above, the entire first and second joints 15, 25 are positioned offset from the third and fourth joints 45, 55, thereby avoiding mutual interference.

[0124] <Blocking structure for both ends of second sealed flow path> In order to block both ends of the second sealed flow path F2 from the outside when the both ends of the second sealed flow path F2 are detached from the supply pipe 46 and the recovery pipe 56, respectively, the third and fourth connecting devices C3 and C4 are provided with third and fourth shut-off valves 48 and 58, respectively, as shown in FIG. 1A.

[0125] The third shut-off valve 48 can open and close the above-mentioned passage region R3. That is, the third shut-off valve 48 can be switched between an open position where the cooling medium M can pass through the passage region R3 (third pipe joint 45) of the third connecting device C3 and a closed position where the cooling medium M cannot pass through the passage region R3. In the example of FIG. 1A , the passage region R3 is an internal region of the third joint 45, and the third shut-off valve 48 is provided in the third joint 45.

[0126] 1A, the third shutoff valve 48 is provided inside the third joint 45. When the supply pipe joint 47 is connected to the third joint 45, the third shutoff valve 48 is automatically or manually operated to the open position.

[0127] Also, when the supply pipe fitting 47 is removed from the third fitting 45, the third shut-off valve 48 is automatically or manually operated to the closed position.

[0128] The fourth shutoff valve 58 can open and close the above-mentioned passage region R4. That is, the fourth shutoff valve 58 can be switched between an open position where the cooling medium M can pass through the passage region R4 (fourth pipe joint 55) of the fourth connecting device C4 and a closed position where the cooling medium M cannot pass through the passage region R4. In the example of FIG. 1A , the passage region R4 is an internal region of the fourth joint 55, and the fourth shutoff valve 58 is provided in the fourth joint 55.

[0129] 1A, the fourth shutoff valve 58 is provided inside the fourth joint 55. When the recovery pipe joint 57 is connected to the fourth joint 55, the fourth shutoff valve 58 is automatically or manually operated to the open position.

[0130] Also, when the recovery pipe joint 57 is removed from the fourth joint 55, the fourth shutoff valve 58 is automatically or manually operated to the closed position.

[0131] The configuration and function of the third and fourth shutoff valves 48, 58 may be the same as the configuration and function of the first and second shutoff valves 18, 28 described above with respect to the first sealed flow path F1.

[0132] <Supply Pipe and Recovery Pipe Shutoff Structure for Second Sealed Flow Path> In order to shut off the flow path portions of the circulation flow path Fc other than the second sealed flow path F2 from the outside when both ends of the second sealed flow path F2 are detached from the supply pipe 46 and the recovery pipe 56, the second supply pipe connection device Cs2 and the second recovery pipe connection device Cr2 are respectively provided with the supply-side shutoff valve 49 and the recovery-side shutoff valve 59 shown in Fig. 1A. The second supply pipe connection device Cs2 and the second recovery pipe connection device Cr2 may be components of the coolant circulation device 100.

[0133] The supply-side shutoff valve 49 can open and close the above-mentioned passage region Rs2. That is, the supply-side shutoff valve 49 can be switched between an open position where the cooling medium M can pass through the passage region Rs2 (supply pipe joint 47) of the second supply pipe connection device Cs2 and a closed position where the cooling medium M cannot pass through the passage region Rs2. In the example of FIG. 1A, the passage region Rs2 is an internal region of the supply pipe joint 47, and the supply-side shutoff valve 49 is provided in the supply pipe joint 47.

[0134] 1A, the supply-side shutoff valve 49 is provided inside the supply pipe joint 47. When the supply pipe joint 47 is connected to the third joint 45, the supply-side shutoff valve 49 is automatically or manually operated to the open position.

[0135] When the supply pipe joint 47 is removed from the third joint 45, the supply-side shutoff valve 49 is automatically or manually operated to the closed position.

[0136] The recovery-side shutoff valve 59 can open and close the above-mentioned passage region Rr2. That is, the recovery-side shutoff valve 59 can be switched between an open position where the cooling medium M can pass through the passage region Rr2 (recovery pipe joint 57) of the second recovery pipe connection device Cr2, and a closed position where the cooling medium M cannot pass through the passage region Rr2. In the example of FIG. 1A , the passage region Rr2 is an internal region of the recovery pipe joint 57, and the recovery-side shutoff valve 59 is provided in the recovery pipe joint 57.

[0137] 1A, the recovery-side shutoff valve 59 is provided inside the recovery pipe joint 57. When the recovery pipe joint 57 is connected to the fourth joint 55, the recovery-side shutoff valve 59 is automatically or manually operated to the open position.

[0138] When the recovery pipe joint 57 is removed from the fourth joint 55, the recovery side shutoff valve 59 is automatically or manually operated to the closed position.

[0139] The supply-side shutoff valve 49 and the recovery-side shutoff valve 59 may have the same configurations and functions as the supply-side shutoff valve 19 and the recovery-side shutoff valve 29 described above with respect to the first sealed flow path F1.

[0140] As described above, even if the gaseous radioactive nuclide generated in the internal space 3a of the target container 3 leaks into the circulation flow path Fc including the second sealed flow path F2 on the upper surface 32e side of the second closing member 5b, after the target material 1 in the target container 3 is irradiated with a particle beam, the flow path portion of the circulation flow path Fc other than the second sealed flow path F2 (the portion including the supply pipe 46 and the recovery pipe) can be closed by the supply side shut-off valve 49 and the recovery side shut-off valve 59.

[0141] <Configuration for Cooling the Target Container> The storage device 10 may include a third flow path member 61 attached to the target container 3. The third flow path member 61 is formed with a refrigerant flow path F3 through which a cooling medium flows to cool the target container 3. This cooling medium may be a liquid such as water.

[0142] 1A, a fitting hole 61a into which the target vessel 3 is removably fitted from above is formed in the upper surface 61b of the third flow path member 61. This fitting hole 61a opens to the upper surface 61b of the third flow path member 61. The target vessel 3 is fitted into the fitting hole 61a of the third flow path member 61 so that the outer bottom surface and outer peripheral surface of the target vessel 3 are in close contact with the bottom surface and inner peripheral surface of the fitting hole 61a, respectively.

[0143] 1A , the lower portion of the target container 3 is fitted into the fitting hole 61a of the third flow path member 61, and as described above, the pressing member 7 and the upper portion of the target container 3 are fitted into the fitting hole 12d of the first flow path member 12, and in this state, the upper surface 61b of the third flow path member 61 and the lower surface 12f of the first flow path member 12 may be in close contact with each other. In this state, the third flow path member 61 and the first flow path member 12 may be removably coupled to each other.

[0144] For example, through holes through which fastening members (e.g., bolts or screws, not shown) penetrate in the vertical direction may be formed in the cover member 33, the second flow path member 32, and the first flow path member 12 at positions aligned with each other on the outer circumferential side of the target container 3, and threaded holes (not shown) may be formed in the upper surface 61b of the third flow path member 61 at positions aligned with these through holes. The front ends of the fastening members may be threadedly engaged with the threaded holes in the upper surface 61b of the third flow path member 61 through these through holes, thereby sandwiching and fixing the cover member 33 and the first and second flow path members 32 between the heads of the rear ends of the fastening members and the third flow path member 61. These through holes and threaded holes may be formed at a plurality of positions that do not interfere with the first and second sealed flow paths F1 and F2 when viewed from above, and the fastening members may be provided at each of these positions as described above.

[0145] The refrigerant flow path F3 of the third flow path member 61 may be formed so as to contact the outer surface (e.g., the outer bottom surface) of the target container 3. Joints 63, 64 may be provided at both ends of the refrigerant flow path F3, respectively. These joints 63, 64 may be attached to the third flow path member 61. A pipe joint 72 at the tip of a refrigerant supply pipe 71 that supplies the cooling medium to the refrigerant flow path F3 is removably attached to one of the joints 63, and a pipe joint 74 at the tip of a refrigerant discharge pipe 73 that discharges the cooling medium that has flowed through the refrigerant flow path F3 from the refrigerant flow path F3 is removably attached to the other joint 64.

[0146] 7 shows the state in which the storage device 10 according to this embodiment is placed at the predetermined installation position relative to the particle beam irradiation device (designated by reference numeral 20 in FIG. 7). In this state, the particle beam from the particle beam irradiation device 20 is irradiated onto the target material 1 placed in the recess D in the target container 3 of the storage device 10.

[0147] A shaping device 400 and a particle beam adjusting mechanism 200 are provided between the particle beam irradiation device 20 and the storage device 10. The shaping device 400 and the particle beam adjusting mechanism 200 shape the cross-sectional shape of the particle beam emitted from the particle beam irradiation device 20 into a narrowed shape.

[0148] The particle beam adjusting mechanism 200 includes a support structure 201 and a beam aperture forming body 202. The storage device 10 in the predetermined installation position is located below the particle beam adjusting mechanism 200.

[0149] The storage device 10 is attached to the support structure 201. For example, the flange portion 33c of the cover member 33 and the flange portion 201a of the support structure 201 are connected by, for example, a quick coupling or bolts (not shown). This places the storage device 10 in the predetermined installation position. The support structure 201 has an attachment portion 201b to which the beam aperture former 202 is attached and which supports the beam aperture former 202.

[0150] 8 is a view taken along the line VIII-VIII in FIG. 7, but shows only the beam aperture forming member 202. The beam aperture forming member 202 has a plurality of current detection portions 202a that are separated from one another. When viewed from above, these current detection portions 202a form beam passage holes 202b through which a charged particle beam (e.g., a proton beam) passes as a particle beam.

[0151] When the storage device 10 is attached to the support structure 201 as described above, the center of the beam passage hole 202b may coincide with the center of the depression D in the target container 3 of the storage device 10 when viewed from the direction of travel of the charged particle beam (vertical direction).

[0152] The cross-sectional dimension of the beam passage hole 202b may be, for example, but is not limited to, 5 mm or less, 3 mm or less, or 1 mm or less. Here, the cross-sectional dimension of the beam passage hole 202b may be the diameter if the cross section is circular, or may be the maximum dimension in each direction along the cross section (i.e., each direction perpendicular to the passage direction of the particle beam) if the cross section is not circular.

[0153] In the example of Fig. 8, the number of current detection units 202a is four, but this is not limited to this. Each current detection unit 202a may be formed in a plate shape. Each current detection unit 202a is formed from a material that generates a current when hit by a charged particle beam. The material is, for example, tantalum, but is not limited to this.

[0154] In this way, when the charged particle beam strikes the current detection portion 202a, a current is generated in the current detection portion 202a, and based on this current, the beam shape control portion 300 controls the charged particle beam shaping device 400 (e.g., multiple electromagnets) so that no current is generated in the current detection portion 202a. This causes the charged particle beam to be shaped into a sharply focused cross-sectional shape so that the charged particle beam passes through the beam passage hole 202b without striking any of the current detection portions 202a. As a result, the charged particle beam with such a sharply focused cross-sectional shape can be accurately irradiated onto the small target material 1 placed in the recess D in the target container 3.

[0155] Furthermore, by attaching, for example, a water cooling mechanism to the beam aperture forming member 202, a high intensity particle beam can be used.

[0156] The present invention is not limited to the above-described embodiment, and various modifications may be made within the scope of the technical concept of the present invention. For example, the storage device 10 according to the embodiment of the present invention may not have all of the above-described features, or may have only some of the above-described features.

[0157] Furthermore, any of the following modified examples 1 to 6 may be adopted alone, or any combination of modified examples 1 to 6 may be adopted. In this case, the points not described below may be the same as those described above.

[0158] (Modification 1) In the internal space 3a of the target container 3, the depression D included in the bottom surface 3a2 may be formed so that the cross section along the horizontal plane becomes smaller as it extends downward. That is, the depression D may be formed in a tapered shape that becomes smaller as it extends downward.

[0159] 9A and 9B, the entire bottom surface 3a2 of the internal space 3a may be the depression D, or as shown in Figures 9C and 9D, the depression D may be formed in a portion (e.g., the center) of the bottom surface 3a2 facing upward in the internal space 3a of the target container 3. In the latter case, the depression D may have a conical shape, for example, as shown in Figures 9C and 9D.

[0160] (Modification 2) The storage device 10 may include the target container 3, the first closing member 5a, and the pressing member 7 (for example, the configuration shown in FIG. 2 ), and may not have any other configuration. In this case, a flange portion to be attached to the flange portion 201a described above may be provided on the pressing member 7 or another portion.

[0161] (Modification 3) The second sealed flow path F2 and the configuration related to the second sealed flow path F2 may not be provided in the storage device 10. In this case, the second closing member 5b may be attached to the upper surface 12e of the first flow path member 12 by an appropriate member or the like.

[0162] (Modification 4) Each pair of a first connecting device C1 and a first supply pipe connecting device Cs1, a pair of a second connecting device C2 and a first recovery pipe connecting device Cr1, a pair of a third connecting device C3 and a second supply pipe connecting device Cs2, and a pair of a fourth connecting device C4 and a second recovery pipe connecting device Cr2 may have other configurations as long as they are connectable to each other and separable from each other, and when separated from each other, each valve body V automatically closes each passage area R1, Rs1, R2, Rr1, R3, Rs2, R4, Rr2.

[0163] An example of this other configuration may be a "Quick Connect" (e.g., a double-end shut-off type quick connect) sold by Swagelok. That is, the first coupling 15, the first shut-off valve 18, the supply pipe coupling 17, and the supply-side shut-off valve 19 in the pair of the first connecting device C1 and the first supply pipe connecting device Cs1 may constitute a "quick connect." The same applies to the other pairs.

[0164] (Modification Example 5) Figure 10 shows other configuration examples of each pair of a first connection device C1 and a first supply pipe connection device Cs1, a pair of a second connection device C2 and a first recovery pipe connection device Cr1, a pair of a third connection device C3 and a second supply pipe connection device Cs2, and a pair of a fourth connection device C4 and a second recovery pipe connection device Cr2.

[0165] The first connecting device C1 and the first supply pipe connecting device Cs1 may be configured as follows: The first joint 15 is located upstream of the first shutoff valve 18 and adjacent to (e.g., directly connected to) the first shutoff valve 18. The first joint 15 and the first shutoff valve 18 are coupled to each other and to the first flow path forming structure 11. The supply pipe joint 17 is located downstream of the supply-side shutoff valve 19 and adjacent to (e.g., directly connected to) the supply-side shutoff valve 19. The first joint 15 and the supply pipe joint 17 are connectable to and separable from each other. The opening and closing operations of the first shutoff valve 18 and the supply-side shutoff valve 19 may be independent of the connection and disconnection of the first joint 15 and the supply pipe joint 17. The first shutoff valve 18 and the supply-side shutoff valve 19 may be, for example, ball valves, and may be opened and closed manually.

[0166] Similarly, the second connecting device C2 and the first recovery pipe connecting device Cr1 may be configured as follows: The second joint 25 is located downstream of the second shutoff valve 28 and adjacent to (e.g., directly connected to) the second shutoff valve 28. The second joint 25 and the second shutoff valve 28 are coupled to each other and to the first flow path forming structure 11. The recovery pipe joint 27 is located upstream of the recovery side shutoff valve 29 and adjacent to (e.g., directly connected to) the recovery side shutoff valve 29. The second joint 25 and the recovery pipe joint 27 are connectable to and separable from each other. The opening and closing operations of the second shutoff valve 28 and the recovery side shutoff valve 29 may be independent of the connection and disconnection of the second joint 25 and the recovery pipe joint 27. The second shutoff valve 28 and the recovery side shutoff valve 29 may be, for example, ball valves, and may be opened and closed manually.

[0167] The third connecting device C3 and the second supply pipe connecting device Cs2 may be configured as follows: The third joint 45 is located upstream of the third shutoff valve 48 and adjacent to (e.g., directly connected to) the third shutoff valve 48. The third joint 45 and the third shutoff valve 48 are coupled to each other and to the second flow path forming structure 31. The supply pipe joint 47 is located downstream of the supply-side shutoff valve 49 and adjacent to (e.g., directly connected to) the supply-side shutoff valve 49. The third joint 45 and the supply pipe joint 47 are connectable to and separable from each other. The opening and closing operations of the third shutoff valve 48 and the supply-side shutoff valve 49 may be independent of the connection and disconnection of the third joint 45 and the supply pipe joint 47. The third shutoff valve 48 and the supply-side shutoff valve 49 may be, for example, ball valves, and may be opened and closed manually.

[0168] Similarly, the fourth connecting device C4 and the second recovery pipe connecting device Cr2 may be configured as follows: The fourth joint 55 is located downstream of the fourth shutoff valve 58 and adjacent to (e.g., directly connected to) the fourth shutoff valve 58. The fourth joint 55 and the fourth shutoff valve 58 are coupled to each other and to the second flow path forming structure 31. The recovery pipe joint 57 is located upstream of the recovery side shutoff valve 59 and adjacent to (e.g., directly connected to) the recovery side shutoff valve 59. The fourth pipe joint 55 and the recovery pipe joint 57 are connectable to and separable from each other. The opening and closing operations of the fourth shutoff valve 58 and the recovery side shutoff valve 59 may be independent of the connection and disconnection of the fourth pipe joint 55 and the recovery pipe joint 57. The fourth shutoff valve 58 and the recovery side shutoff valve 59 may be, for example, ball valves, and may be opened and closed manually.

[0169] According to such a modified example 5, when the first connecting device C1 and the first supply pipe connecting device Cs1, which are connected to each other, are to be separated, first, the first shutoff valve 18 and the supply-side shutoff valve 19, which are open, are closed before the separation, and then the first joint 15 and the supply pipe joint 17, which are connected to each other, are detached from each other to separate them from each other. As a result, the radionuclide radon-222 ( ２２２The same applies to the second connecting device C2 and the first recovery pipe connecting device Cr1.

[0170] (Modification 6) The storage device 10 may include a cover sheet 3c that covers the recess D from above so as to confine the target material 1 placed in the recess D in the recess D (or a local space including the recess D). The cover sheet 3c is placed in the internal space 3a of the target container 3 and is attached directly or indirectly to the target container 3. The cover sheet 3c is formed of a material (e.g., beryllium, titanium, etc.) that is transmissive to the particle beam in its thickness direction. The thickness of the cover sheet 3c may be, for example, 10 μm or more and 100 μm or less.

[0171] 11A shows a configuration example in which the cover sheet 3c is directly attached to the target container 3 (bottom surface 3a2). In FIG. 11A, the cover sheet 3c is attached to the outer periphery of the bottom surface 3a2 surrounding the upper opening of the recess D, thereby blocking the recess D (the upper opening) from above. In this regard, the storage device 10 may include an attachment member 3d. The attachment member 3d covers the outer periphery of the cover sheet 3c and is attached to the outer periphery of the bottom surface 3a2 so as to press the cover sheet 3c against the outer periphery. When viewed from above, the attachment member 3d has a beam through hole 3d1 formed in the area overlapping with the recess D so as to penetrate the attachment member 3d in the vertical direction.

[0172] The mounting member 3d is removably attached to the outer periphery of the bottom surface 3a2. For example, as shown in Fig. 11A, the mounting member 3d may be attached to the outer periphery of the bottom surface 3a2 by fastening members 3e (bolts, screws, etc.). This attachment method may be the same as the attachment method of the pressing member 7 described above.

[0173] 11B shows another example of a configuration in which the cover sheet 3c is indirectly attached to the target container 3. In FIG. 11B, the cover sheet 3c is attached to the target container 3 via an attachment portion 3f. The attachment portion 3f is removably inserted into the internal space 3a so as to fit into the internal space 3a. The attachment portion 3f may have, for example, a cylindrical shape. The attachment portion 3f has a through hole 3fh penetrating in the vertical direction, and the through hole 3hf is vertically connected to the recess D. The cover sheet 3c is attached to the attachment portion 3f so as to be positioned midway through the through hole 3fh and cover the recess D from above, thereby blocking a local space including the recess D from above. This local space includes the portion of the through hole 3fh located below the cover sheet 3c and the recess D.

[0174] The mounting portion 3f may be sandwiched and held between the outer peripheral portion of the bottom surface 3a2 surrounding the upper opening of the recess D and the pressing member 7. In this case, as shown in Fig. 11B, the beam through hole 7a of the mounting member 7 may have the same dimensions and shape as the through hole 3fh when viewed from above.

[0175] The mounting portion 3f has a first member 3f1 and a second member 3f2 that sandwich the cover sheet 3c from above and below. The second member 3f2 may be attached to the bottom surface of the first member 3f1 by fastening members 3i (bolts, screws, etc.). This attachment method may be the same as the attachment method for the pressing member 7 described above. The mounting portion 3f (second member 3f2) is installed on the outer periphery of the bottom surface 3a2 of the internal space 3a.

[0176] In this modified example 6, as in the above-described embodiment and modified example 1, the recess D may have a shape in which the cross-sectional area in the horizontal plane is constant as shown in Figures 11A and 11B (for example, a cylindrical or prismatic shape), or a shape in which the cross-sectional area decreases downward as shown in Figures 11C and 11D (for example, a conical shape), or may have another shape. Note that the configurations shown in Figures 11C and 11D are the same as those in Figures 11A and 11B, respectively, except for the shape of the recess D.

[0177] 1 target substance, 3 target container, 3a internal space, 3a1 opening, 3a2 bottom surface, 3b upper surface, 3b1 annular groove, 3b2 screw hole, 5a first closing member, 5a1 upper surface, 5b second closing member, 5c third closing member, 7 pressing member, 7a beam through hole, 7b through hole, 8 fastening member, 8a head, 9, 9a, 9b annular sealing member, 10 storage device, 11 first flow path forming structure, 12 first flow path member, 12a beam through hole, 12b, 12c flow path hole, 12b1, 12c1 opening, 12d fitting hole, 12e upper surface, 12e1 annular groove, 12e2 screw hole, 12f lower surface, 13 fastening member, 14 annular sealing member, 15 first joint, 16 supply pipe, 17 Supply pipe joint, 18 First shutoff valve, 19 Supply side shutoff valve, 20 Particle beam irradiation device, V Valve body V, Va Tip portion, E Elastic member, N Nut, 25 Second joint, 26 Recovery pipe, 27 Recovery pipe joint, 28 Second shutoff valve, 29 Recovery side shutoff valve, 31 Second flow path forming structure, 31a Beam through hole, 32 Second flow path member, 32a Beam through hole, 32b, 32c Flow path hole, 32b1, 32c1 Opening, 32d Fitting hole, 32d1 Bottom surface, 32e Top surface, 32f Groove, 32g Through hole, 33 Cover member, 33a Beam through hole, 33b Protrusion, 33b1 Annular groove, 33c Flange portion, 35 Pressing member, 35a Through hole, 37 Annular seal member, 45 Third joint, 46: Supply pipe, 47: Supply pipe joint, 48: Third shutoff valve, 49: Supply-side shutoff valve, 55: Fourth joint, 56: Recovery pipe, 57: Recovery pipe joint, 58: Fourth shutoff valve, 59: Recovery-side shutoff valve, 61: Third flow path member, 61a: Fitting hole, 61b: Upper surface, 63,64 Joint, 71 Coolant supply pipe, 72 Joint, 73 Coolant discharge pipe, 74 Joint, 80 Drying device (jig), 81 Cover body, 81a Airtight space, 81b Wall portion, 81b1 Side wall, 81b2 Upper wall, 81c Gas inlet hole, 81d Gas discharge hole, 82 Gas discharge pipe, 82a Tip opening, 83 Gas pipe joint, 84 Gas inlet pipe, 100 Cooling medium circulation device, Fc Circulation flow path, 101 Compressor, 102 Heat exchanger, 200 Particle beam adjustment mechanism, 201 Support structure, 201a Flange portion, 201b Mounting portion, 202 Beam hole former, 202a Current detection portion, 202b Beam passing hole, 300 Beam shape control unit, 400 Shaping device, C1 to C4 First to fourth connection devices, Cs1 first supply pipe connection device, Cs2 second supply pipe connection device, Cr1 first recovery pipe connection device, Cr2 second recovery pipe connection device, D recess, F1 first sealed flow path, F2 second sealed flow path, F3 refrigerant flow path, M cooling medium, R1, R2, Rs1, Rs2, Rr1, Rr2 passing area,

Claims

1. A storage device for storing a target material that is an irradiation target of a particle beam, comprising: a target container having an internal space with an upward opening and a lower bottom surface; and a closure member that is attached to the target container so as to close the opening and seal the internal space, and that is permeable to the particle beam, wherein the bottom surface includes a downwardly recessed depression in which the target material is placed.

2. The storage device of claim 1, wherein the recess is formed in a portion of the bottom surface facing upward.

3. The storage device according to claim 1, wherein the recess is formed so that a cross section of the recess taken along a horizontal plane becomes smaller as it progresses downward.

4. The storage device according to claim 1, further comprising a cover sheet that covers the recess from above so as to confine the target substance placed in the recess.

5. A storage device as described in claim 1, wherein the opening is formed in the upper surface of the target container, and the closing member is formed in a sheet shape that is transparent to the particle beam and is attached to the upper surface of the target container so as to block the opening.

6. A storage device as described in claim 1, further comprising a pressing member attached to the target container so as to cover an upper surface of the closing member and press the closing member against the upper surface of the target container, wherein when viewed from above, the pressing member has a beam through hole formed in an area including a portion that overlaps with the recess.

7. A storage device as described in claim 6, wherein an annular groove is formed on the upper surface of the target container surrounding the opening, and an annular sealing member is disposed in the annular groove, and the annular sealing member, together with the closing member, is sandwiched between the pressing member and the target container.

8. The storage device of claim 7, wherein a plurality of annular grooves are formed on the upper surface of the target container, surrounding the opening at different positions from each other, and a plurality of annular sealing members are disposed in each of the plurality of annular grooves.

9. A storage device as claimed in any one of claims 1 to 8, further comprising a flow path forming structure for forming a sealed flow path for flowing a cooling medium on an upper surface of the closing member, wherein in the flow path forming structure, a beam through hole penetrating in the vertical direction is formed in a portion which overlaps with the sealed flow path and the recess when viewed from above, and wherein the closing member is a first closing member, and the flow path forming structure comprises a second closing member which closes the beam through hole so as to seal the sealed flow path from above, and wherein the second closing member is configured to be transparent to the particle beam.

10. A storage device as described in claim 9, comprising a first connection device attached to one end of the sealed flow path, capable of connecting a cooling medium supply pipe to the sealed flow path, and forming a passage area through which the cooling medium from the supply pipe flows to the sealed flow path, the first connection device having a first joint capable of connecting to and separating from the supply pipe, and a shut-off valve capable of opening and closing the passage area; and a second connection device attached to the other end of the sealed flow path, capable of connecting a cooling medium recovery pipe to the sealed flow path, and forming a passage area through which the cooling medium flows from the sealed flow path to the recovery pipe, the second connection device having a second joint capable of connecting to and separating from the recovery pipe, and a shut-off valve capable of opening and closing the passage area of ​​the second connection device.

11. The storage apparatus according to claim 10, further comprising: a cooling medium circulation device which includes the supply pipe and the recovery pipe and circulates the cooling medium in a circulation flow path which includes the sealed flow path and the supply pipe and the recovery pipe; a supply pipe connection device which is provided at one end of the supply pipe and connectable to the first joint and forms a passage area through which the cooling medium from the supply pipe flows to the first connection device, the supply pipe connection device having a supply pipe joint which can be connected to the first joint and separated from the first joint, and a supply side cutoff valve which can open and close the passage area of ​​the supply pipe connection device; and a recovery pipe connection device which is provided at one end of the recovery pipe and connectable to the second joint and forms a passage area through which the cooling medium from the second connection device flows to the recovery pipe, the recovery pipe connection device having a recovery pipe joint which can be connected to the second joint and separated from the second joint, and a recovery side cutoff valve which can open and close the passage area of ​​the recovery pipe connection device.

12. The storage device described in claim 10, wherein the sealed flow path and the flow path forming structure are respectively a first sealed flow path and a first flow path forming structure, and the storage device further comprises a second flow path forming structure that forms a second sealed flow path through which a cooling medium flows on an upper surface of the second closing member, and in the second flow path forming structure, a beam through hole that penetrates in the vertical direction is formed in a portion that overlaps with the second sealed flow path and the recess when viewed from above, and the second flow path forming structure comprises a third closing member that closes the beam through hole of the second flow path forming structure so as to seal the second sealed flow path from above, and the third closing member is configured to be transparent to the particle beam.

13. The storage device according to claim 12, further comprising: a third connection device attached to one end of the second sealed flow path, capable of connecting a second supply pipe of the cooling medium to the second sealed flow path, and forming a passage area through which the cooling medium from the second supply pipe flows to the second sealed flow path, the third connection device having a third joint capable of connecting to the second supply pipe and separating from the second supply pipe, and a shutoff valve capable of opening and closing the passage area of ​​the third connection device; and a fourth connection device attached to the other end of the second sealed flow path, capable of connecting a second return pipe of the cooling medium to the second sealed flow path, and forming a passage area through which the cooling medium flows from the second sealed flow path to the second return pipe, the fourth connection device having a fourth joint capable of connecting to the second return pipe and separating from the second return pipe, and a shutoff valve capable of opening and closing the passage area of ​​the fourth connection device.

14. A storage device as described in claim 13, wherein a portion of the first and second joints and a portion of the third and fourth joints are located on the same imaginary horizontal plane, and when viewed from above, the first and second sealed flow paths extend so as to intersect with each other at a position overlapping with the recess, thereby preventing the first and second joints and the third and fourth joints from interfering with each other.

15. The storage device according to claim 13, further comprising: a cooling medium circulation device including the second supply pipe and the second return pipe, and circulating the cooling medium in a circulation flow path including the second sealed flow path and the second supply pipe and the second return pipe; a supply pipe connection device provided at one end of the second supply pipe, connectable to the third joint, and forming a passage area through which the cooling medium from the second supply pipe flows to the third connection device, the supply pipe connection device having a supply pipe joint capable of being connected to and separated from the third joint, and a supply side shutoff valve capable of opening and closing the passage area of ​​the supply pipe connection device; and a return pipe connection device provided at one end of the second return pipe, connectable to the fourth joint, and forming a passage area through which the cooling medium from the fourth connection device flows to the second return pipe, the return pipe connection device having a return pipe joint capable of being connected to and separated from the fourth joint, and a return side shutoff valve capable of opening and closing the passage area of ​​the return pipe connection device.

16. A storage device according to any one of claims 1 to 7, comprising a flow path member attached to the target container and forming a refrigerant flow path through which a cooling medium for cooling the target container flows.

17. A method for producing a target nuclide using a storage device according to any one of claims 1 to 8, comprising the steps of: placing a target material in the recess on the bottom surface through the opening of the target container of the storage device in a sealed environment; closing the opening with the closure member to seal the internal space; thereafter, moving the storage device from the sealed environment; and positioning the storage device relative to the particle beam irradiation device so that the bottom surface faces upward and the recess is located on the passage path of a particle beam from a particle beam irradiation device. In this state, the particle beam from the particle beam irradiation device is irradiated from above onto the target material in the recess, thereby producing a target nuclide by a nuclear reaction of the target nuclide contained in the target material.

18. A method for producing a target nuclide as claimed in claim 17, wherein, before closing the opening with the closing member, a solution of the target material is poured into the recess and the solution is dried to place the solid target material in the recess; in a drying process for drying the solution, a cover body having a gas inlet hole and a gas exhaust hole is used, and a gas exhaust pipe that airtightly penetrates the gas exhaust hole or is airtightly connected to the gas exhaust hole is attached to the cover body; in the drying process, by attaching the cover body to the target container so as to surround an area above the opening of the target container, an airtight space continuing upward from the opening of the target container is partitioned by the cover body, and a tip opening of the gas exhaust pipe faces the recess; in this state, a dry gas is introduced into the airtight space through the gas inlet hole, the dry gas is caused to flow from the tip opening of the gas exhaust pipe into the gas exhaust pipe, and then the dry gas is exhausted to the outside of the cover body through the gas exhaust pipe and the gas exhaust hole.