Target Illumination System

Abstract

To provide a target irradiation system which can take out a target from an irradiation device, and can quickly melt a radioisotope by a melting device, and a method for recovering a radioisotope from a solid target.SOLUTION: A conveyance device 22 conveys a solid target 10 from a target irradiation device 20 for irradiating a solid target 10 with a charge particle beam B to a melting device 21 for recovering a radioisotope. Here, the target irradiation device 20 and the melting device 21 are arranged in a cyclotron chamber 152 provided in a building 150. Therefore, both a step of irradiating the solid target 10 with the charge particle beam and a step of recovering the radioisotope by melting are performed in the cyclotron chamber 152. Therefore, the solid target 10 is taken out from the target irradiation device 20, and the radioisotope can be quickly melted by the melting device 21.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a target irradiation system and a method for recovering radioisotopes from a solid target. [Background technology]

[0002] As shown in Patent Document 1, a self-shielded cyclotron system is known that houses a cyclotron and has a self-shield that prevents radiation emitted from the cyclotron from being released to the outside. In recent years, devices have been developed that obtain solid radioisotopes (RIs) by irradiating a target having a metal layer with a charged particle beam. Such radioisotopes are used to manufacture radiopharmaceuticals used in PET (positron emission tomography) scans in hospitals, etc. For example, in Patent Document 2, a target to which a solid radioisotope is attached is transported to a melting device, and the radioisotope is melted in the melting device, thereby recovering the RI. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-105293 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-115229 Summary of the Invention [Problem to be solved by the invention]

[0004] Here, the target becomes activated after being irradiated with the charged particle beam, so it is necessary to remove the target from the irradiation device and quickly melt the radioisotopes in a melting device.

[0005] An object of the present invention is to provide a target irradiation system that can remove a target from an irradiation device and quickly melt the radioactive isotopes in a melting device, and a method for recovering radioactive isotopes from a solid target. [Means for solving the problem]

[0006] The target irradiation system of the present invention is a target irradiation system that irradiates a solid target having a metal layer with a charged particle beam emitted from a particle accelerator to produce radioactive isotopes from the metal layer, and is equipped with a target irradiation device that is located in a room provided in a building and holds the solid target at an irradiation position for the charged particle beam, allowing the solid target to be irradiated with the charged particle beam, and a melting device that is located in the room and melts radioactive isotopes that have adhered to the solid target after irradiation with the charged particle beam by the target irradiation device has been completed.

[0007] In the target irradiation system according to the present invention, the target irradiation device holds the solid target at a charged particle beam irradiation position and enables the solid target to be irradiated with the charged particle beam. As a result, radioactive isotopes are formed in the metal layer of the solid target at locations irradiated with the charged particle beam. Furthermore, the melting device dissolves the radioactive isotopes attached to the solid target after the irradiation with the charged particle beam by the target irradiation device has been completed. As a result, the radioactive isotopes can be recovered by recovering the solution. Here, the target irradiation device and the melting device are located in a room provided in a building. Therefore, both the process of irradiating the solid target with the charged particle beam and the process of recovering the radioactive isotopes by melting are performed indoors. Therefore, the solid target can be removed from the target irradiation device and the radioactive isotopes can be quickly melted in the melting device.

[0008] The target irradiation system may further include a support that supports the target irradiation device relative to the floor of the chamber, and the melting device may be supported relative to the floor by the support. In this case, since the target irradiation device and the melting device are supported by a common support, they can be located close to each other.

[0009] The target irradiation system may further include a transport device that transports the solid target released from the target irradiation device to the melting device. In this case, the solid target can be quickly transported from the target irradiation device to the melting device.

[0010] The target irradiation system may be provided in a room, and may further include a shielding shield that houses the particle accelerator and the target irradiation device and that blocks radiation emitted from the particle accelerator and the target irradiation device, and the melting device may be provided in the shielding shield. In this case, the shielding shield can block radiation when the solid target is transferred from the target irradiation device to the melting device.

[0011] The target irradiation system may further include a transport device that transports the solid target from the target irradiation device to the melting device, and a control unit, and the control unit may control the transport device to transport the solid target held in the target irradiation device to the melting device after the metal layer is irradiated with the charged particle beam. In this way, the transport of the solid target by the transport device is automatically performed by the control unit. This can further reduce radiation exposure to workers. In addition, by having the control unit automatically transport the solid target, work time can be shortened.

[0012] The target irradiation system may be provided in a room, house a particle accelerator and a target irradiation device therein, and further include a shielding shield for blocking radiation emitted from the particle accelerator and the target irradiation device. The target irradiation system may also include a container for covering the melting device within the shielding shield, and an exhaust unit for exhausting gas within the container to the outside of the shielding shield. In this case, when the melting liquid of the melting device is vaporized, the container prevents the gas from diffusing into the shielding shield. Furthermore, the exhaust unit exhausts the gas within the container to the outside of the shielding shield. This prevents corrosion of other equipment within the shielding shield by the gas.

[0013] The target irradiation system may further include a transport device for transporting the solid targets, and the transport device may be capable of supporting multiple solid targets. In this case, the transport device can transport the multiple solid targets to the irradiation position and the melting position without removing the solid targets midway. This reduces the impact of radiation exposure due to the removal operation.

[0014] The target irradiation system may further include a support device for supporting the solid target, the target irradiation device including an irradiation port from which the charged particle beam is emitted, the melting device including a melting port for supplying and recovering the melting liquid, and the support device may be connected to the irradiation port and the melting port. In this case, the support device can be used as both a part of the target irradiation device and a part of the melting device.

[0015] The dissolution device may be provided with a plurality of dissolution ports for supplying and recovering the dissolution solution, in which case the dissolution process for multiple radioisotopes can be carried out without the need to replace the dissolution ports.

[0016] The target irradiation system irradiates a solid target having a metal layer with a charged particle beam emitted from a particle accelerator to produce radioactive isotopes from the metal layer, and includes a target irradiation device that holds the solid target at an irradiation position for the charged particle beam to enable irradiation of the solid target with the charged particle beam, and a melting device that melts the radioactive isotopes attached to the solid target after irradiation with the charged particle beam by the target irradiation device, where the target irradiation device and the melting device are located in the same room in a building. This target irradiation system can achieve the same functions and effects as the above-mentioned target irradiation system.

[0017] A method for recovering radioisotopes from a solid target includes recovering radioisotopes from a metal layer attached to a solid target. The method includes: irradiating the solid target with a charged particle beam using a target irradiation device located in a shielded chamber installed in a building to generate radioisotopes in the solid target; transporting the solid target after the irradiation with the charged particle beam is completed using a transport device capable of transporting the solid target to a melting device located in the shielded chamber; and melting the radioisotopes attached to the solid target using the melting device. According to this recovery method, the steps of irradiating the solid target with a charged particle beam, transporting the solid target, and recovering the radioisotopes by melting are all performed within the shielded chamber. Therefore, the solid target can be removed from the target irradiation device and the radioisotopes can be quickly melted in the melting device. Furthermore, radiation can be shielded during each step. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide a target irradiation system in which the target can be removed from the irradiation device and the radioactive isotopes can be quickly melted in a melting device, and a method for recovering radioactive isotopes from a solid target. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a schematic diagram illustrating a self-shielded cyclotron system including a target irradiation system according to an embodiment of the present invention. [Figure 2] FIG. 1 is a perspective view of a solid target. [Figure 3] FIG. 2 is an expanded view of the target illumination system. [Figure 4] 10 is a flowchart showing the processing contents of a control unit. [Figure 5] FIG. 2 is an expanded view showing the operation of the target illumination system. [Figure 6] FIG. 2 is an expanded view showing the operation of the target illumination system. [Figure 7] FIG. 2 is an expanded view showing the operation of the target illumination system. [Figure 8] FIG. 2 is an enlarged view showing the operation of the target illumination system. [Figure 9] FIG. 2 is an enlarged view showing the operation of the target illumination system. [Figure 10] FIG. 10 is an enlarged view showing a self-shielded cyclotron equipped with a target irradiation system according to a modified example. [Figure 11] FIG. 10 is a conceptual configuration diagram showing a target irradiation system according to a modified example. [Figure 12] FIG. 10 is a schematic configuration diagram showing a target irradiation system according to a modified example. [Figure 13] FIG. 13 is a schematic diagram showing the main parts of the target irradiation system shown in FIG. [Figure 14] FIG. 10 is a perspective view showing an example of a specific structure of a target exchanger. [Figure 15] FIG. 10 is a cross-sectional view showing a state in which the support device is pressed against the irradiation port. [Figure 16] FIG. 10 is a cross-sectional view showing a state in which the support device is pressed against the dissolution port. [Figure 17] FIG. 1 is a front view of a dissolution port. [Figure 18] FIG. 2 is a schematic diagram illustrating the operation of the target illumination system. [Figure 19] FIG. 2 is a schematic diagram illustrating the operation of the target illumination system. [Figure 20] FIG. 2 is a schematic diagram illustrating the operation of the target illumination system. [Figure 21] FIG. 2 is a schematic diagram illustrating the operation of the target illumination system. [Figure 22] FIG. 2 is a schematic diagram illustrating the operation of the target illumination system. [Figure 23] FIG. 2 is a schematic diagram illustrating the operation of the target illumination system. DETAILED DESCRIPTION OF THE INVENTION

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and redundant explanations will be omitted.

[0021] As shown in FIG. 1, the self-shielded cyclotron system 100 is a system installed inside a building 150. The self-shielded cyclotron system 100 according to this embodiment is a system that produces radioisotopes (hereinafter, may be referred to as RI) using a charged particle beam. The self-shielded cyclotron system 100 can be used, for example, as a PET cyclotron, and the RI produced by this system is used, for example, to produce radiopharmaceuticals (including radiopharmaceuticals) that are radioisotope-labeled compounds (RI compounds). Radioisotope-labeled compounds used in PET examinations (positron emission tomography examinations) in hospitals, etc. include: 18 F-FLT (fluorothymidine), 18 F-FMISO (fluorosonidazole), 11 C-Raclopride, etc.

[0022] The self-shielded cyclotron system 100 includes a cyclotron 2 (particle accelerator), a target irradiation system 3, and a shielding shield 4. The self-shielded cyclotron system 100 is installed on a floor 151 of a building 150 in a cyclotron room 152 inside the building. The cyclotron room 152 is a room covered with concrete (shielding walls). Therefore, by using the self-shielded cyclotron system 100, a user can obtain radioisotopes on-site within the building.

[0023] The cyclotron 2 is an accelerator that emits a charged particle beam. The cyclotron 2 is a circular accelerator that supplies charged particles from an ion source into an acceleration space, accelerates the charged particles in the acceleration space, and outputs a charged particle beam. The cyclotron 2 has a pair of magnetic poles, a vacuum box, and an annular yoke that surrounds the pair of magnetic poles and the vacuum box. The pair of magnetic poles faces each other with a predetermined gap between them inside the vacuum box. Charged particles are multiply accelerated within the gap between the pair of magnetic poles. Examples of charged particles include protons and heavy particles (heavy ions). In this embodiment, the cyclotron 2 has multiple ports 2a that emit the charged particle beam. A target irradiation device 20, described below, is formed in one of the multiple ports 2a. The cyclotron 2 adjusts the trajectory of the charged particle beam within the acceleration space and extracts the charged particle beam from the desired port 2a.

[0024] The shielding shield 4 is provided indoors (inside the cyclotron chamber 152), houses the cyclotron 2 and a target irradiation device 20 (described later), and shields against radiation emitted from the cyclotron 2 and the target irradiation device 20 (described later). The shielding shield 4 is disposed inside a building, houses the cyclotron 2, and prevents radiation emitted from the cyclotron 2 from being emitted into the cyclotron chamber 152. The shielding shield 4 covers the cyclotron 2 from all directions, thereby shielding against radiation in all directions. In this embodiment, the shielding shield 4 has a hexahedral box-like structure, but the shape is not particularly limited. The shielding shield 4 separates the internal space of the building 150 (the cyclotron chamber 152) from the internal space 120 of the self-shielded cyclotron system 100. The internal space of the building 150 may be configured as a space in which other equipment is installed or through which workers and the like can pass. Therefore, the self-shielded cyclotron system 100 of this embodiment differs from a system in which the cyclotron 2 is simply placed inside a building, and the surrounding walls that form the building do not correspond to the shielding shield 4. The walls of the shielding shield 4 are made of materials such as polyethylene, iron, lead, and heavy concrete. In addition to the cyclotron 2, a vacuum pump and wiring for operating the cyclotron 2 are also placed inside the shielding shield 4. Components of the target irradiation system 3 are also placed inside the shielding shield 4. Therefore, the shielding shield 4 functions as a support that supports a target irradiation device 20 (described later) on a floor 151 of the cyclotron room 152. A melting device 21 (described later) is supported on the floor 151 by the shielding shield 4, which also functions as a support. With the above-mentioned configuration, the target irradiation device 20 (described later) and the melting device 21 (described later) are placed in the same room (cyclotron room 152) provided in the building 150.

[0025] The target irradiation system 3 is a part that irradiates a solid target 10 with a charged particle beam and dissolves and collects radioisotopes generated by the irradiation. The target irradiation system 3 is formed near the outer periphery of the cyclotron 2 and is placed inside a shielding shield 4. The solution containing the radioisotopes obtained in the target irradiation system 3 is sent via a transport pipe 161 to a device 160 such as a purification device that purifies the radioisotopes in the solution or a synthesis device that synthesizes pharmaceuticals.

[0026] The solid target 10 will be described with reference to FIG. 2. The solid target 10 includes a target substrate 13 and a metal layer 11. Specifically, as shown in FIG. 2, the solid target 10 has a metal layer 11 formed as a target material on a target substrate 13 made of a metal plate. The metal layer 11 is not limited to a layer of a highly pure metal, but may also be a layer of metal oxide. The target substrate 13 is set in an apparatus, and the metal layer 11 is irradiated with a charged particle beam B, thereby generating a trace amount of radioactive isotopes 12 in the irradiated portion. As a result, the radioactive isotopes 12 are contained in the metal layer 11. A material that is insoluble in the solvent, such as Au or Pt, is used as the material for the target substrate 13. The target substrate 13 shown in FIG. 2 is formed in a disk shape, but the shape and thickness are not particularly limited. The material for the metal layer 11, which is the target material, can be, for example, 64 Ni, 89 Y, 100 Mo, 68 Zn, etc. Examples of the radioisotope 12 generated in response to the metal layer 11 include: 64 Cu, 89 Zr, 99m Tc, 68Examples of suitable metals include Ga. The metal layer 11 is formed by plating the front surface 10a of the target substrate 13. Alternatively, a plate-shaped metal layer may be attached to the target substrate 13 instead of plating. The metal layer 11 shown in FIG. 2 is formed in a circular shape at the center of the target substrate 13, but the shape and position are not particularly limited. Cooling water or the like is supplied to the rear surface 10b of the target substrate 13 when the metal layer 11 is irradiated with the charged particle beam B. This allows the cooling water or the like to absorb heat generated by the metal layer 11 (and the target substrate 13) due to irradiation with the charged particle beam B.

[0027] Next, the configuration of the target irradiation system 3 will be described in detail with reference to Fig. 3. The target irradiation system 3 irradiates a solid target 10 having a metal layer 11 with a charged particle beam emitted from a cyclotron 2 to generate radioactive isotopes of the metal layer 11. The target irradiation system 3 includes a target irradiation device 20, a melting device 21, a transport device 22, and a control unit 50.

[0028] The target irradiation device 20 is disposed in a room (inside the cyclotron chamber 152) provided in the building 150, and is a device that holds the solid target 10 at an irradiation position of the charged particle beam B, enabling the solid target 10 to be irradiated with the charged particle beam B. The target irradiation device 20 holds the solid target 10 having a metal layer 11 at the irradiation position of the charged particle beam B. Furthermore, the target irradiation device 20 releases the holding of the solid target 10 after the irradiation of the solid target 10 with the charged particle beam B is completed. Specifically, the target irradiation device 20 includes a fixed unit 23 and a movable unit 24. The target irradiation device 20 holds the solid target 10 at the irradiation position RP by sandwiching the solid target 10 between the fixed unit 23 and the movable unit 24. Both the fixed unit 23 and the movable unit 24 are housed in the shielding shield 4.

[0029] The fixed unit 23 is a cylindrical member fixed to the outer periphery of the cyclotron 2. The fixed unit 23 is provided in a state extending along the irradiation axis BL of the charged particle beam B emitted from the cyclotron 2 and protruding from the outer periphery of the cyclotron 2. The fixed unit 23 has an internal space 26 for passing the charged particle beam B at a position corresponding to the irradiation axis BL of the charged particle beam B. The internal space 26 is formed to extend along the irradiation axis BL, with the irradiation axis BL as its center line. The fixed unit 23 and the internal space 26 are arranged to be inclined downward with respect to the horizontal direction.

[0030] The fixed unit 23 has a surface on its lower end side that extends horizontally as an opposing surface 23a that faces the upper surface of the movable unit 24. The fixed unit 23 holds the solid target 10 at the position of the opposing surface 23a. A sealing member such as an O-ring is provided on the opposing surface 23a. The opposing surface 23a abuts against the solid target 10 via the sealing member, thereby also functioning as a sealing surface for the solid target 10. In this embodiment, the location on the opposing surface 23a where the internal space 26 opens (and further the position of the irradiation axis BL therein) corresponds to the irradiation position RP. Therefore, when the target irradiation device 20 holds the solid target 10, it holds the solid target 10 so that the metal layer 11 of the solid target 10 is positioned at the opening of the internal space 26.

[0031] The fixed unit 23 is provided with a vacuum foil 25 at a midpoint of the internal space 26. The vacuum foil 25 maintains a vacuum in the region of the internal space 26 upstream of the vacuum foil 25.

[0032] The fixing unit 23 has a flow path 27 that sprays a gas such as helium onto the charged particle beam B and the vacuum foil 25 arranged at the irradiation position. The flow path 27 has a main flow path 27a and branch flow paths 27b and 27c that branch off from the main flow path 27a. The branch flow path 27b extends toward the vacuum foil 25 and sprays gas onto the vacuum foil 25. The branch flow path 27c extends toward the irradiation position RP of the solid target 10 and sprays gas onto the held solid target 10.

[0033] The movable unit 24 moves up and down relative to the fixed unit 23. When placing the solid target 10 on the carrier tray 60, the movable unit 24 is disposed at a position spaced downward from the fixed unit 23. When holding the solid target 10 at the irradiation position RP, the movable unit 24 is disposed at a position where the solid target 10 is sandwiched between the movable unit 24 and the fixed unit 23 (see FIG. 5).

[0034] The movable unit 24 has a cylindrical shape extending in the vertical direction. A portion of the outer circumferential surface of the movable unit 24 is connected to a drive mechanism 28 that moves in the vertical direction. A small diameter portion 29 that protrudes upward is formed at the upper end of the movable unit 24. The diameter of the small diameter portion 29 is smaller than at least the diameter of the inner circumferential portion of a carrier tray 60 described below. As a result, the small diameter portion 29 passes through a through hole on the inner circumferential side of the carrier tray 60 and comes into contact with the solid target 10, pressing the solid target 10 against the fixed unit 23 above.

[0035] The movable unit 24 has a surface extending horizontally at the upper end of the small diameter portion 29 as an opposing surface 24a that faces the opposing surface 23a of the fixed unit 23. A sealing member such as an O-ring is provided on the opposing surface 24a. The opposing surface 24a abuts against the solid target 10 via the sealing member, and thereby also functions as a sealing surface for the solid target 10. When the target irradiation device 20 holds the solid target 10, the opposing surface 23a and the opposing surface 24a sandwich the solid target 10 therebetween (see FIG. 5).

[0036] The movable unit 24 has an internal space 31 that opens at the opposing surface 24a. The internal space 31 is a space for storing a cooling medium for cooling the solid target 10. A supply pipe 32 for supplying the cooling medium and a discharge pipe 33 for discharging the cooling medium are connected to the internal space 31.

[0037] The melting device 21 is disposed inside the room (inside the cyclotron chamber 152) and melts radioisotopes attached to the solid target 10 after irradiation with the charged particle beam B by the target irradiation device 20. The melting device 21 melts the metal layer 11 containing the radioisotope in the solid target 10. The melting device 21 includes a fixed unit 40 and a movable unit 41. The melting device 21 holds the solid target 10 by sandwiching it between the fixed unit 40 and the movable unit 41. While holding the solid target 10, the melting device 21 supplies a dissolving liquid to at least the metal layer 11, dissolves the metal in the metal layer 11 containing the radioisotope in the dissolving liquid, and recovers the dissolving liquid together with the radioisotope. Hydrochloric acid, nitric acid, or the like is used as the dissolving liquid. The fixed unit 40 and the movable unit 41 are housed in a shielding shield 4.

[0038] The fixed unit 40 is disposed at a position spaced apart from the fixed unit 23 of the target irradiation device 20 on the opposite side of the cyclotron 2. The fixed unit 40 includes a cylindrical main body 48 extending in the vertical direction, and a support portion 49 that supports the main body 48 on its outer periphery. The main body 48 has, at its lower end, a surface that extends horizontally as an opposing surface 40a that faces the movable unit 41. The solid target 10 is held at the position of the opposing surface 40a. A sealing member such as an O-ring is provided on the opposing surface 40a. The opposing surface 40a abuts against the solid target 10 via the sealing member, and therefore also functions as a sealing surface for the solid target 10. The solid target 10 is held at the position of the opposing surface 40a.

[0039] The main body 48 has an internal space 42 that opens at the facing surface 40a. The internal space 42 is a dissolving tank for storing a dissolving liquid for dissolving the metal layer 11 of the solid target 10. A supply / suction pipe 43 for supplying the dissolving liquid and a suction pipe 44 for suctioning the dissolving liquid and suctioning gas within the internal space 42 are connected to the internal space 42. The diameter of the internal space 42 that opens at the facing surface 40a is at least smaller than the diameter of the solid target 10 and larger than the diameter of the metal layer 11. Note that the diameter of the facing surface 40a itself is not particularly limited, but in this embodiment it is smaller than the diameter of the solid target 10.

[0040] The support portion 49 is a cylindrical member having an end wall that extends radially outward from the outer circumferential surface of the main body portion 48. The support portion 49 has a through hole 49a at its center for inserting the main body portion 48. A flange portion is formed near the upper end of the main body portion 48. This flange portion engages with the upper edge of the through hole 49a of the main body portion 48.

[0041] The movable unit 41 moves up and down relative to the fixed unit 40. When the solid target 10 is attached to the fixed unit 40, the movable unit 41 is disposed at a position spaced downward from the fixed unit 40. When the metal layer 11 of the solid target 10 is melted by the melting device 21, the movable unit 41 is disposed at a position where the solid target 10 is sandwiched between the movable unit 41 and the fixed unit 40 (see FIG. 9).

[0042] The movable unit 41 includes a main body 46 and a receiving tray 47 provided on the upper end side of the main body 46. The main body 46 has a cylindrical shape extending in the vertical direction. A portion of the outer circumferential surface of the main body 46 is connected to a drive mechanism (not shown) that moves in the vertical direction. A groove structure for supporting the receiving tray 47 is formed at the upper end of the main body 46.

[0043] The receiving tray 47 includes a bottom wall 47a extending horizontally at the upper end of the main body 46 and a side wall 47b extending upward from the outer periphery of the bottom wall 47a. The bottom wall 47a has a horizontally extending facing surface 41a facing the facing surface 40a of the fixed unit 40. The facing surface 41a abuts against the solid target 10. When the melting device 21 holds the solid target 10, the facing surfaces 40a and 41a sandwich the solid target 10 therebetween (see FIG. 9 ). The inner diameter of the side wall 47b is larger than the diameter of the solid target 10. Furthermore, when the solid target 10 is held, the upper end of the side wall 47b is positioned higher than the solid target 10. Therefore, if the melting liquid leaks from the internal space 42 while the metal layer 11 of the solid target 10 is being melted, the receiving tray 47 receives the melting liquid. The bottom wall portion 47a has a recessed and protruding structure on the lower surface thereof for fitting with the groove structure of the main body portion 46.

[0044] In the dissolving apparatus 21, the main body 48 and the receiving pan 47, which come into contact with the dissolving liquid, are configured as replaceable disposable parts. That is, the main body 48 is detachably attached to the support 49. The receiving pan 47 is detachably attached to the main body 46. Here, "detachable" refers to an attachment mode in which, even once attached, an operator can easily remove them through normal maintenance work. For example, examples of a detachable attachment structure include a structure that is attached using bolts or a structure that is attached by fitting or engaging with a sufficient strength to prevent disassembly during dissolving. For example, a fixing structure such as welding or fusion does not fall under the category of a detachable form. The replaceable main body 48 and receiving pan 47 can be made of a material with high acid resistance, such as Teflon (registered trademark).

[0045] The transport device 22 transports the solid target 10, which has been released from the target irradiation device 20, to the melting device 21. The transport device 22 transports the solid target 10 from the target irradiation device 20 to the melting device 21. The transport device 22 is arranged inside the shielding shield 4. The transport device 22 includes a transport tray 60 that transports the solid target 10 placed thereon, and a transport driver 61 that drives the transport tray 60. The transport tray 60 is an annular member having a support portion on its upper surface for supporting the solid target 10. The transport tray 60 has a groove formed around the entire periphery on the inner periphery of its upper surface, and the outer periphery of the lower surface of the solid target 10 is placed in the groove. The transport driver 61 is configured by a combination of a drive source and a drive force transmission mechanism (not shown). The transport drive unit 61 transports the transport tray 60 to the melting device 21 by moving the transport tray 60 horizontally from the position of the target irradiation device 20 when transporting the solid target 10 irradiated with a charged particle beam to the melting device 21. The transport drive unit 61 transports the transport tray 60 from the area between the fixed unit 23 and the movable unit 24 of the target irradiation device 20 to the area between the fixed unit 40 and the movable unit 41 of the melting device 21. The transport drive unit 61 may be configured using a known drive source such as a rotary motor or a linear motor and a drive force transmission mechanism such as a gear or a rod. The transport drive unit 61 may have any configuration as long as it can avoid interference with other components and perform the desired operation. The position of the transport tray 60 at each stage will be described in detail when explaining the operation below.

[0046] The control unit 50 controls the self-shielded cyclotron system 100. The control unit 50 is composed of a CPU, RAM, ROM, an input / output interface, etc. The control unit 50 determines the control content based on detection signals from each sensor in the device and a program stored in the ROM, and controls each component in the self-shielded cyclotron system 100. Note that the control unit 50 does not have to be composed of a single processing device, and may be composed of multiple processing devices. The control unit 50 may be located inside the shielding shield 4 or outside the shielding shield 4.

[0047] The control unit 50 includes an irradiation control unit 51, a holding control unit 52, a melting control unit 53, and a transport control unit 54. The irradiation control unit 51 mainly controls the cyclotron 2 and controls operations related to the irradiation of the charged particle beam B by the cyclotron 2. The holding control unit 52 mainly controls the target irradiation device 20 and controls operations related to the holding of the solid target 10 by the target irradiation device 20. The melting control unit 53 mainly controls the melting device 21 and controls operations related to melting the metal layer 11 of the solid target 10. The transport control unit 54 mainly controls the transport device 22 and controls operations related to the transport of the solid target 10. After the metal layer 11 is irradiated with the charged particle beam B, the transport control unit 54 controls the transport device 22 to transport the solid target 10 held in the target irradiation device 20 to the melting device 21.

[0048] Next, the operation of the target irradiation system 3 will be described together with the details of the control process by the control unit 50 with reference to Fig. 3 to Fig. 9. Fig. 4 is a flowchart showing the details of the control process by the control unit 50. Figs. 4 to 9 are diagrams showing the state of the target irradiation system 3 at each stage during operation. For the sake of explanation, the control unit 50 and the transport drive unit 61 are omitted from Figs. 4 to 9. Also, reference numerals that are not used in the explanation may be omitted as appropriate.

[0049] As shown in FIG. 4, the control unit 50 performs a process for setting the solid target 10 in the target irradiation system 3 (step S10). In the process of S10, the control unit 50 places the target irradiation device 20, the melting device 21, and the transport device 22 in their initial positions. The control unit 50 drives the drive units of each component to bring the target irradiation system 3 into the state shown in FIG. 3. In this state, the movable unit 24 is positioned downwardly away from the fixed unit 23. The movable unit 41 is positioned downwardly away from the fixed unit 40. The transport tray 60 is positioned downwardly away from the fixed unit 23 and at a reference height. Here, the "reference height" refers to a predetermined height position between the fixed unit 23 and the movable unit 24 and between the fixed unit 40 and the movable unit 41 in the height direction. At this height position, the transport tray 60 does not interfere with the units 23, 24, 40, and 41 even when moved horizontally. The control unit 50 may notify the operator via a monitor or the like that the solid target 10 can be set. When the control unit 50 detects that the operator has placed the solid target 10 on the carrier tray 60, it determines that the setting of the solid target 10 has been completed. The control unit 50 may detect that the setting of the solid target 10 has been completed by detection by a sensor or input by the operator.

[0050] Next, the control unit 50 performs a process of holding the solid target 10 at the irradiation position RP of the charged particle beam B (step S20: FIG. 4). In S20, the holding control unit 52 of the control unit 50 controls the drive mechanism 28 of the movable unit 24 to move the movable unit 24 upward. As a result, as shown in FIG. 5, the solid target 10 is sandwiched between the fixed unit 23 and the movable unit 24 at the irradiation position RP. Note that, during the process of the movable unit 24 moving upward, the solid target 10 placed on the transport tray 60 is supported by the movable unit 24 that has passed through the through-hole of the transport tray 60 from below. At this time, the transport tray 60 may rise while being supported by the movable unit 24. Alternatively, the transport tray 60 may be driven to rise together with the movable unit 24.

[0051] Next, the control unit 50 performs a process of irradiating the solid target 10 with the charged particle beam B (step S30: FIG. 4). In S30, the irradiation control unit 51 of the control unit 50 controls the cyclotron 2 to irradiate the solid target 10 with the charged particle beam B. At this time, the holding control unit 52 controls the flow path system so that helium gas or the like is sprayed from the flow path 27 of the fixing unit 23 onto the solid target 10 and the vacuum foil 25. The holding control unit 52 also controls the piping system of the supply pipe 32 and the discharge pipe 33 to flow a cooling medium into the internal space 31 to cool the solid target 10.

[0052] When the process of S30 is completed, the holding control unit 52 of the control unit 50 controls the drive mechanism 28 of the movable unit 24 to move the movable unit 24 downward. As a result, the movable unit 24 returns to its initial position, as shown in Fig. 6. Also, the transport tray 60, with the solid target 10 placed thereon, returns to its reference height position.

[0053] Next, the control unit 50 performs a process of transporting the solid target 10 from the target irradiation device 20 to the melting device 21 (step S40: FIG. 4). In S40, the transport control unit 54 of the control unit 50 controls the transport drive unit 61 (see FIG. 3) of the transport device 22 to horizontally move the transport tray 60 from the target irradiation device 20 to the position of the melting device 21. As a result, as shown in FIG. 7, the transport tray 60 is positioned between the fixed unit 40 and the movable unit 41 while maintaining a position at the reference height in the height direction. As a result, the solid target 10 is positioned at a position facing, on the lower side, the opposing surface 40a where the internal space 42 is opened.

[0054] Next, the control unit 50 performs a process of setting the solid target 10 in the melting device 21 (step S50: FIG. 4). In S50, as shown in FIG. 8, the melting control unit 53 of the control unit 50 controls the piping system of the suction tube 44 to adsorb the solid target 10 onto the facing surface 40a through the internal space 42. Before adsorbing the solid target 10, the transport tray 60 is raised to press the solid target 10 against the facing surface 40a of the main body 48. This crushes an O-ring (not shown) provided between the solid target 10 and the main body 48, sealing the internal space. Thereafter, the transport control unit 54 controls the transport drive unit 61 (see FIG. 3) to move the transport tray 60 to a position on the target irradiation device 20 side. This prevents the transport tray 60 from interfering with the movable unit 41.

[0055] In S50, the dissolution control unit 53 controls the drive unit of the movable unit 41 to move the movable unit 41 upward. As a result, the solid target 10 is sandwiched between the opposing surface 40a of the fixed unit 40 and the opposing surface 41a of the movable unit 41, as shown in Fig. 9. At this time, the solid target 10 is held in the receiving tray 47 and pressed against the main body 48 from above.

[0056] Next, the control unit 50 performs a process of recovering radioisotopes contained in the metal layer 11 by melting the metal layer 11 of the solid target 10 using the melting device 21 (step S60: FIG. 4). In S60, the dissolution control unit 53 of the control unit 50 controls the pipeline system of the supply / suction pipe 43 to supply the dissolving liquid SL from the supply / suction pipe 43 to the internal space 42. The dissolution control unit 53 also controls the pipeline system of the suction pipe 44 to suck and recover the dissolving liquid SL in which the radioisotopes have been dissolved using the supply / suction pipe 43. This completes the control process shown in FIG. 4. After the radioisotopes have been recovered, the operator removes the solid target 10 together with the main body 48 and the receiving tray 47 and takes it out of the shielding shield 4.

[0057] As shown in FIG. 1 , the solution SL in which the radioisotopes have been dissolved is discharged outside the shield 4 and sent to an apparatus 160, such as a purification apparatus for purifying the radioisotopes in the solution SL or a synthesis apparatus for synthesizing pharmaceuticals. The purification apparatus or synthesis apparatus may be located in the same building 150 or in a different building (facility). When the solution SL is to be transported to a synthesis apparatus or the like in the same building 150, the solution SL is sent to the synthesis apparatus or the like through a transport pipe 161 connected to the supply / suction pipe 43. Because the solution SL emits radiation, the transport pipe 161 is covered with a shielding shield or passes through a shielding wall (floor or wall) of the building 150. When the solution SL is to be transported to another building, the collected solution SL is stored in a shielding box (a box that suppresses the emission of radiation to the outside, such as a lead box), and the shielding box is transported by automobile or the like.

[0058] Next, the operation and effect of the target irradiation system 3 according to this embodiment will be described.

[0059] The target irradiation system 3 of this embodiment is a target irradiation system 3 that irradiates a solid target 10 having a metal layer 11 with a charged particle beam B emitted from a cyclotron 2 to generate radioactive isotopes of the metal layer 11, and is equipped with a target irradiation device 20 that is arranged in a cyclotron chamber 152 provided in a building 150 and holds the solid target 10 at an irradiation position of the charged particle beam B to enable irradiation of the solid target 10 with the charged particle beam B, and a melting device 21 that is arranged in the cyclotron chamber 152 and melts radioactive isotopes attached to the solid target 10 after irradiation of the charged particle beam B by the target irradiation device 20 has been completed.

[0060] In the target irradiation system 3, the target irradiation device 20 holds the solid target 10 at an irradiation position of the charged particle beam B, enabling the solid target 10 to be irradiated with the charged particle beam B. As a result, radioactive isotopes are formed in the metal layer 11 of the solid target 10 at locations irradiated with the charged particle beam B. Furthermore, the melting device 21 dissolves the radioactive isotopes attached to the solid target 10 after the irradiation with the charged particle beam B by the target irradiation device 20 is completed. As a result, the radioactive isotopes can be recovered by recovering the solution. Here, the target irradiation device 20 and the melting device 21 are disposed in a cyclotron chamber 152 provided in a building 150. Therefore, both the process of irradiating the solid target 10 with the charged particle beam and the process of recovering the radioactive isotopes by melting them are performed in the cyclotron chamber 152. Therefore, the solid target 10 can be removed from the target irradiation device 20 and the radioactive isotopes can be quickly melted in the melting device 21.

[0061] The target irradiation system 3 further includes a shielding shield 4 as a support part that supports the target irradiation device 20 on the floor 151 of the cyclotron chamber 152, and the melting device 21 is supported on the floor 151 by the support part. In this case, since the target irradiation device 20 and the melting device 21 are supported by a common support part, they can be arranged in close positions.

[0062] The target irradiation system 3 further includes a transport device 22 that transports the solid target 10, which has been released from the holding by the target irradiation device 20, to the melting device 21. In this case, it is possible to quickly transport the solid target 10 from the target irradiation device 20 to the melting device 21.

[0063] The target irradiation system 3 is provided in the cyclotron chamber 152, houses the cyclotron 2 and the target irradiation device 20 therein, and further includes a shielding shield 4 that blocks radiation emitted from the cyclotron 2 and the target irradiation device 20, and the melting device 21 is provided inside the shielding shield 4. In this case, the shielding shield 4 can block radiation when the solid target 10 is transferred from the target irradiation device 20 to the melting device 21.

[0064] The target irradiation system 3 further includes a transport device 22 that transports the solid target 10 from the target irradiation device 20 to the melting device 21, and a control unit 50. The control unit 50 controls the transport device 22 to transport the solid target 10 held in the target irradiation device 20 to the melting device 21 after the metal layer 11 is irradiated with the charged particle beam B. As a result, the transport of the solid target 10 by the transport device 22 is automatically performed by the control unit 50. This makes it possible to further reduce radiation exposure to workers. Furthermore, the automatic transport of the solid target 10 by the control unit 50 makes it possible to shorten the work time.

[0065] The target irradiation system 3 irradiates a solid target 10 having a metal layer 11 with a charged particle beam B emitted from a cyclotron 2 to generate radioactive isotopes of the metal layer 11, and includes a target irradiation device 20 that holds the solid target 10 at an irradiation position for the charged particle beam B to enable the solid target 10 to be irradiated with the charged particle beam B, and a melting device 21 that melts the radioactive isotopes attached to the solid target 10 after irradiation with the charged particle beam B by the target irradiation device 20, and the target irradiation device 20 and the melting device 21 are located in the same cyclotron room 152 provided in a building 150. With this target irradiation system 3, it is possible to obtain the same actions and effects as those described above.

[0066] The method for recovering radioisotopes from a solid target 10 involves recovering radioisotopes from a metal layer 11 attached to the solid target 10. The method involves a target irradiation device 20 located in a shielded room in a building 150 irradiating the solid target 10 with a charged particle beam B to generate radioisotopes in the solid target 10, a transport device 22 capable of transporting the solid target 10 transports the solid target 10, after irradiation with the charged particle beam B, to a melting device 21 located in the shielded room, and the melting device 21 melts the radioisotopes attached to the solid target 10. According to this recovery method, the steps of irradiating the solid target 10 with the charged particle beam B, transporting the solid target 10, and recovering the radioisotopes by melting are all performed within the shielded room. Therefore, the solid target can be removed from the target irradiation device 20 and the radioisotopes can be quickly melted in the melting device 21. Furthermore, radiation can be shielded in each step.

[0067] In the self-shielded cyclotron system 100 according to this embodiment, the target irradiation device 20 holds a target having a metal layer 11 at an irradiation position RP of the charged particle beam B. Therefore, the solid target 10 held by the target irradiation device 20 is irradiated with the charged particle beam B. As a result, radioactive isotopes 12 are formed in the metal layer 11 of the solid target 10 at the locations irradiated with the charged particle beam B. The melting device 21 also includes a melting device that melts the metal layer 11 containing the radioactive isotope in the solid target 10. This allows the radioactive isotope to be recovered by recovering the solution. The transport device 22 transports the solid target 10 from the target irradiation device 20, where the solid target 10 is irradiated with the charged particle beam B, to the melting device 21, where the radioactive isotope is recovered. The target irradiation device 20, the melting device 21, and the transport device 22 are disposed within the shielding shield 4. Therefore, the process of irradiating the solid target 10 with the charged particle beam B, the process of recovering the radioisotopes by dissolving them, and the process of transporting the target between these processes are all performed inside the shield 4. Therefore, in each process, the radiation emitted from the solid target 10 after being irradiated with the charged particle beam is blocked by the self-shield. As a result, safety against exposure when obtaining radioisotopes can be further improved.

[0068] The self-shielded cyclotron system 100 further includes a control unit 50, which may control the transport device 22 to transport the solid target 10 held in the target irradiation device 20 to the melting device 21 after the metal layer 11 is irradiated with the charged particle beam B. In this way, the transport of the solid target 10 by the transport device 22 is automatically performed by the control unit 50. This can further improve safety against radiation exposure. In addition, the automatic transport of the solid target 10 by the control unit 50 can shorten the operation time.

[0069] The present invention is not limited to the above-described embodiment, and various modifications such as those described below are possible within the scope of the present invention.

[0070] For example, a configuration as shown in FIG. 10 may be employed. The self-shielded cyclotron system shown in FIG. 10 may include a housing unit 70 that covers the melting device 21 within the shielding shield 4, and an exhaust unit 71 that exhausts gas within the housing unit 70 to the outside of the shielding shield 4. The housing unit 70 does not cover the target irradiation device 20, but covers only the melting device 21. An opening 70a may be formed in the housing unit 70 at a location through which a transport tray passes. This opening 70a may be closed when a transport tray is not passing through. The exhaust unit 71 may have an exhaust pipe that passes from the housing unit 70 through the shielding shield 4 and communicates with the outside of the shielding shield 4. The exhaust unit 71 may include a pump or the like provided in the exhaust pipe.

[0071] As a result, when the dissolving liquid in the dissolving device 21 is vaporized, the accommodation unit 70 prevents the gas from diffusing into the shielding shield 4. Furthermore, the gas inside the accommodation unit 70 is exhausted to the outside of the shielding shield 4 by the exhaust unit 71. As a result, other devices inside the shielding shield 4 can be prevented from being corroded by the gas.

[0072] Furthermore, the configuration of the target irradiation system shown in each of the drawings of the above-described embodiment is merely an example, and the shape and arrangement may be changed as appropriate as long as they are within the scope of the present invention. For example, the conveying device may employ an arm-shaped gripping unit that grips the target instead of a conveying tray.

[0073] The transport of the target by the transport device was performed automatically by the control unit. Alternatively, the drive of the transport device itself may be performed manually by an operator. Even in this case, the target is housed in a self-shielded chamber, further improving safety against radiation exposure.

[0074] A target irradiation system 3 as shown in Fig. 11(a) may be used. In the example shown in Fig. 11(a), the target irradiation device 20 and the melting device 21 may be placed in an irradiation chamber 153 separate from a cyclotron chamber 152 in a building 150. In this case, the charged particle beam extracted from the cyclotron 2 is transported from the cyclotron chamber 152 to the target irradiation device 20 in the irradiation chamber 153 via a transport line 155. In this case, the target irradiation device 20 and the melting device 21 are supported on the floor 151 of the irradiation chamber 153 by supports 156.

[0075] 11(b) may also be used. In the example shown in FIG. 11(b), the cyclotron 2, the target irradiation device 20, and the melting device 21 are arranged in the same cyclotron chamber 152. In this case, unlike the configuration shown in FIG. 1, the shielding shield 4 may be omitted.

[0076] In the above-described embodiment, a cyclotron is given as an example of a particle accelerator, but the particle accelerator is not limited to a cyclotron. For example, a linear accelerator may be adopted as the particle accelerator.

[0077] 12 may be employed. The target irradiation system 200 includes a fixing unit 211 of a target irradiation device 210, a fixing unit 221 of a melting device 220, a support device 230, a target exchanger 240, and a control unit 260.

[0078] For the purpose of explaining the target irradiation system 200, an XYZ coordinate system is set. The X-axis direction is parallel to the horizontal direction. One side in the X-axis direction (the front side of the paper in FIG. 12) is the positive side in the X-axis direction. The Y-axis direction is perpendicular to the X-axis direction and parallel to the horizontal direction. One side in the Y-axis direction (the left side of the paper in FIG. 12) is the positive side in the Y-axis direction. The up-down direction is the Z-axis direction. The upper side is the positive side in the Z-axis direction.

[0079] 13, the fixed unit 211 of the target irradiation device 210 includes an internal space 213 for passing the charged particle beam B at a position corresponding to the irradiation axis BL of the charged particle beam B. The internal space 213 is formed to extend along the irradiation axis BL with the irradiation axis BL as its center line. In this embodiment, the irradiation axis BL of the charged particle beam B extends parallel to the Y-axis direction. Furthermore, the charged particle beam B is irradiated from the positive side to the negative side in the Y-axis direction. Therefore, the internal space 213 extends parallel to the Y-axis direction.

[0080] The fixed unit 211 includes an irradiation port 212 that emits a charged particle beam B. The irradiation port 212 has a surface that extends parallel to the XZ plane as an opposing surface facing the sealing surface 230a of the support device 230. The irradiation port 212 has an opening that opens to an internal space 213. The charged particle beam B is emitted from the opening.

[0081] The fixing unit 221 of the dissolving device 220 is disposed at a position spaced apart from the fixing unit 211 of the target irradiation device 210 toward the positive side in the X-axis direction. The fixing unit 221 includes a plurality of dissolving ports 222A, 222B for supplying and recovering dissolving solutions SL. The dissolving ports 222A, 222B may recover radioisotopes of different nuclides. Therefore, the dissolving ports 222A, 222B can supply and recover different dissolving solutions SL. However, the dissolving ports 222A, 222B may recover radioisotopes of the same nuclide. The dissolving ports 222A, 222B are disposed adjacent to each other in the X-axis direction. Furthermore, the dissolving ports 222A, 222B have a surface extending parallel to the XZ plane as an opposing surface facing the sealing surface 230a of the support device 230. Center lines SCL, SCL of the opposing surfaces of the dissolution ports 222A, 222B extend parallel to the Y-axis direction while being spaced apart from each other in the X-axis direction. The center lines SCL, SCL of the dissolution ports 222A, 222B are set at the same height as the irradiation axis BL. The dissolution ports 222A, 222B may be detachable from the dissolution apparatus 220. That is, the dissolution ports 222A, 222B may be detachably attached to the mounting table 223. This allows the dissolution port 222 to be replaced depending on the nuclide of the radioisotope.

[0082] The configuration of the dissolution port 222A will be described in detail with reference to Figures 16 and 17. Note that the dissolution port 222B has a configuration similar to that of the dissolution port 222A, and therefore its description will be omitted. The dissolution port 222A has an opposing surface 222a against which the sealing surface 230a of the support device 230 is pressed. The dissolution port 222A also has a flow path 224 and an adsorption structure 226.

[0083] The flow path 224 allows the solution liquid SL to flow. The flow path 224 is formed inside the member of the dissolving port 222A and opens at the opposing surface 222a. The flow path 224 allows the solution liquid SL to flow out from the opening and also sucks the solution liquid SL from the opening. A flow path forming member 227 protrudes toward the negative side in the Y-axis direction from the position of the center line SCL of the opposing surface 222a. The flow path forming member 227 is a member that is inserted into the internal space 233 of the support device 230 to form a flow path for the solution liquid SL in the internal space 233. The flow paths 224 open at positions adjacent to each other in the circumferential direction of the flow path forming member 227. The dissolving port 222A has two flow paths 224, but the number is not particularly limited.

[0084] The suction structure 226 is a mechanism that sucks the sealing surface 230a in contact with the opposing surface 222a. The suction structure 226 has an annular groove 226a centered on the center line SCL. The suction structure 226 also has a vacuum exhaust path 226b formed in the dissolution port 222A. The vacuum exhaust path 226b opens at the position of the groove 226a.

[0085] 12 and 13, the support device 230 is a device that supports the solid target 10. The support device 230 is connected to the irradiation port 212 and also to the dissolving ports 222A and 222B. Therefore, the support device 230 functions as a movable unit of the target irradiation device 210. The support device 230 also functions as a movable unit of the dissolving device 220. In this embodiment, the target exchanger 240 can mount multiple support devices 230, as described below. Therefore, the target irradiation system 200 can be provided with multiple support devices 230 depending on the application. In this embodiment, the target irradiation system 200 is provided with two support devices 230A and 230B.

[0086] The configuration of the support device 230 will be described in detail with reference to FIG. 15. As shown in FIG. 15, the support device 230 is a member having a substantially cylindrical shape. A center line CL of the support device 230 extends parallel to the Y-axis direction. The support device 230 includes a first member 231 and a second member 232. The support device 230 is divided into the first member 231 and the second member 232 at a midpoint in the longitudinal direction, i.e., in the Y-axis direction. The first member 231 is disposed on the positive side in the Y-axis direction, i.e., on the upstream side in the irradiation direction of the charged particle beam B. The second member 232 is disposed on the negative side in the Y-axis direction, i.e., on the downstream side in the irradiation direction of the charged particle beam B.

[0087] The support device 230 supports the solid target 10 by sandwiching the solid target 10 between a first member 231 and a second member 232. The support device 230 supports the solid target 10 so that it is inclined with respect to the center line CL. The inclination direction of the solid target 10 is not particularly limited. Here, the solid target 10 is inclined so as to move upward (toward the positive side in the Z-axis direction) as it moves from the positive side to the negative side in the Y-axis direction. The first member 231 has a support surface 231a at an end on the negative side in the Y-axis direction. The second member 232 has a support surface 232a at an end on the positive side in the Y-axis direction. The support surface 231a of the first member 231 and the support surface 232a of the second member 232 face each other in parallel. The support surfaces 231a and 232a are inclined in the same direction as the inclination direction of the solid target 10 described above. The support surfaces 231a and 232a are provided with seal portions each having an O-ring near the end portion on the outer circumferential side of the solid target 10.

[0088] The first member 231 has the above-mentioned sealing surface 230a at its end on the positive side in the Y-axis direction. Therefore, the first member 231 functions as a member connected to the irradiation port 212 and connected to the dissolving ports 222A and 222B. A seal having an O-ring is provided on the sealing surface 230a. The first member 231 has an internal space 233 extending parallel to the Y-axis direction at the center line CL. The internal space 233 extends from the sealing surface 230a to the support surface 231a. This exposes the solid target 10 to the internal space 233. The internal space 233 functions as a transport path of the target irradiation device 210 that guides the charged particle beam B to the solid target 10. The internal space 233 also functions as a dissolving tank of the dissolving device 220 that circulates the dissolving liquid SL. Since the first member 231 is a member that allows the charged particle beam B to pass through and the dissolving liquid SL to flow through, it is preferable that the material of the first member 231 be a material that is chemical-resistant, radiation-resistant, and heat-resistant, such as Nb or ceramic.

[0089] When the support device 230 is connected to the irradiation port 212, the sealing surface 230a of the first member 231 is pressed against the irradiation port 212. Furthermore, the internal space 233 and the internal space 213 are in communication with each other. The support device 230 is disposed so that the center line CL coincides with the irradiation axis BL. In this state, the position where the irradiation axis BL intersects with the surface 10a of the solid target 10 is the irradiation position RP.

[0090] The second member 232 functions as a cooling structure for cooling the solid target 10. The second member 232 has a groove 234 at the position of the support surface 232a. In the internal space of the groove 234, the back surface 10b of the solid target 10 is exposed. Therefore, the cooling medium W supplied to the groove 234 comes into contact with the solid target 10. The second member 232 has cooling channels 236 and 237 extending in the Y-axis direction. The cooling channels 236 and 237 are connected to the groove 234. The cooling channel 236 supplies the cooling medium W to the groove 234. The cooling channel 237 recovers the cooling medium W from the groove 234. Since the second member 232 is a member for cooling the solid target 10, it is preferable to use a rust-resistant material such as SUS as the material for the second member 232.

[0091] Next, as shown in FIG. 16 , when the support device 230 is connected to the dissolution port 222A, the sealing surface 230a of the first member 231 is pressed against the opposing surface 222a of the dissolution port 222A. The support device 230 is positioned so that its center line CL coincides with the center line SCL of the dissolution port 222A. A portion of the sealing surface 230a faces the groove 226a of the chucking structure 226. As a result, the sealing surface 230a is chucked to the groove 226a, which is evacuated. Furthermore, the flow path forming member 227 is inserted into the internal space 233. As a result, a flow path for the dissolution liquid SL is formed within the internal space 233. The internal space 233 is in communication with the opening of the flow path 224. The dissolution liquid SL supplied from the flow path 224 comes into contact with the surface 10a of the solid target 10. The dissolution liquid SL in which the radioisotope is dissolved is recovered from the flow path 224.

[0092] Next, the target exchanger 240 will be described. As shown in FIGS. 12 and 13, the target exchanger 240 functions as a transport device that transports the solid target 10. The target exchanger 240 supports the solid target 10 via the support devices 230. The target exchanger 240 includes a holder 241 to which a plurality of support devices 230 can be attached. Therefore, the target exchanger 240 can support a plurality of solid targets 10. Furthermore, the holder 241 is slidable in the X-axis direction with the plurality of support devices 230 attached. Therefore, the holder 241 can transport the solid target 10 together with the plurality of support devices 230 in the X-axis direction.

[0093] 14, a description will be given of an example of a specific structure of the target exchanger 240. As shown in FIG. 14, the target exchanger 240 includes a base plate 242, a first slide plate 243, a second slide plate 244, a first cylinder 246, a second cylinder 247, and a third cylinder 248.

[0094] The base plate 242 is a member that serves as a base for mounting the first and second slide plates 243, 244. A guide rail 242a (see FIG. 12) extending in the Y-axis direction is provided on the upper surface of the base plate 242. The base plate 242 is connected perpendicularly to a fixing plate 249 that fixes the target exchanger 240 to the cyclotron.

[0095] The first slide plate 243 is a plate-like member having a rectangular outer shape in a plan view. A guide rail 251 extending along the X-axis direction is provided on the edge of the first slide plate 243 on the positive side in the Y-axis direction. A first cylinder 246 is attached to the side surface of the first slide plate 243 on the negative side in the Y-axis direction. The first cylinder 246 advances and retreats a drive shaft in the Y-axis direction, causing the holder 241 to move back and forth in the Y-axis direction together with the first slide plate 243. A second cylinder 247 is mounted on the upper surface of the first slide plate 243. The drive shaft of the second cylinder 247 can advance and retreat in the X-axis direction.

[0096] A third cylinder 248 is mounted on the upper surface of the first slide plate 243. The drive shaft of the third cylinder 248 is movable back and forth in the Y-axis direction. The drive shaft of the second cylinder 247 is connected to the third cylinder 248. Therefore, when the second cylinder 247 moves the drive shaft back and forth in the X-axis direction, the third cylinder 248 moves back and forth in the X-axis direction together with the holder 241 with which the drive shaft is engaged (details will be described later).

[0097] A mounting plate 252 extending in the Y-axis direction is attached to the upper surface of the third cylinder 248. An abutter 253 is attached to the end of the mounting plate 252 on the positive side in the Y-axis direction. The abutter 253 comes into contact with a microswitch 259 provided on the second slide plate 244, which will be described later, thereby detecting the position of the second slide plate 244 in the X-axis direction.

[0098] The second slide plate 244 has a rectangular parallelepiped base 256 and a holder 241 erected on the base 256. A liner 255 with a U-shaped cross section extending in the X-axis direction is attached to the underside of the base 256. The holder 241 is rectangular in front view. The holder 241 has four holding holes 257 for holding the support devices 230, and the approximately cylindrical support devices 230 are fitted into and held in these holding holes 257. The four holding holes 257 are arranged side by side along the X-axis direction. This allows the holder 241 to hold a maximum of four support devices 230. In this embodiment, the holder 241 holds two support devices 230A and 230B, but can also hold two additional support devices 230.

[0099] Four microswitches 259 are attached to the front surface of the base 256 of the second slide plate 244 at the same pitch as the holding holes 257. The position of the second slide plate 244 in the X-axis direction is detected when the attacker 253 abuts against these microswitches 259. In addition, an engagement hole 261 is provided below each microswitch 259. The engagement hole 261 has approximately the same size as the diameter of the drive shaft of the third cylinder 248, and is configured so that the drive shaft can engage with this engagement hole 261. As a result, the holder 241 moves back and forth in the X-axis direction when driven by the second cylinder 247.

[0100] As described above, the target exchanger 240 can transport the supported solid target 10 together with the support device 230 in the X-axis direction. The target exchanger 240 transports the support device 230 to a position facing the irradiation port 212 or the dissolving ports 222A, 222B. At this time, the target exchanger 240 includes a mechanism for pressing the support device 230 against the irradiation port 212 or the dissolving ports 222A, 222B. Specifically, as shown in FIGS. 12 and 13 , the target exchanger 240 includes push-out mechanisms 270A, 270B. The push-out mechanisms 270A, 270B include a support member 271 connected to the first slide plate 243, a cylinder 272 that moves a drive shaft back and forth in the Y-axis direction, and a push-out member 273 that pushes out the support device 230. The push-out member 273 is provided on the drive shaft of the cylinder 272. As a result, cylinder 272 moves push-out member 273 to the positive side in the Y-axis direction, thereby pressing support device 230 toward dissolving device 220. As shown in Fig. 13, push-out mechanism 270A is provided at a position facing support device 230A. Push-out mechanism 270B is provided at a position facing support device 230B. For example, when holder 241 positions support device 230A at a position facing dissolving port 222B (see Fig. 20), push-out mechanism 270A presses support device 230A against dissolving port 222B.

[0101] The control unit 260 controls the operation of the target exchanger 240 by transmitting control signals to each driving unit (cylinder) of the target exchanger 240. An example of the control content by the control unit 260 will be described with reference to Fig. 13 and Figs. 18 to 23. However, the operation of the target irradiation system 200 is not limited to the following example, and the number of solid targets 10 and the number of nuclides may be changed as appropriate.

[0102] 13 and 18 to 23 show an example of the operation when a radioisotope of one nuclide is recovered using two solid targets 10. First, as shown in FIG. 13, two support devices 230A and 230B are held by a holder 241. The support device 230A is held in the first holding hole 257 as seen from the positive side in the X-axis direction. The support device 230B is held in the second holding hole 257 as seen from the positive side in the X-axis direction. The control unit 260 controls the second cylinder 247 (see FIG. 14) of the target exchanger 240 to place the holder 241 at a position facing the fixing unit 211. At this time, the holding hole 257 on the most positive side in the X-axis direction of the holder 241, i.e., the support device 230A, is placed at a position facing the irradiation port 212. This position is referred to as the "initial position." In the following description, this control content will be expressed as "the control unit 260 places the support device 230A at a position facing the irradiation port 212." Similar expressions will be used for this control content and other control content with the same meaning.

[0103] Next, as shown in FIG. 18 , the control unit 260 controls the first cylinder 246 of the target exchanger 240 to move the first slide plate 243 (see FIG. 12 ) toward the positive side in the Y-axis direction, thereby pressing the support device 230A against the irradiation port 212. At this time, the support device 230B also moves toward the positive side in the Y-axis direction, but the support device 230B is not pressed against any other member. In the following description, this control content will be expressed as "the control unit 260 presses the support device 230A against the irradiation port 212." Similar expressions will be used for this control content and other control content with the same meaning. The control unit 260 controls the target irradiation device 210 to irradiate the solid target of the support device 230A with the charged particle beam B. When the irradiation is completed, the control unit 260 releases the support device 230A from pressing it against the irradiation port 212.

[0104] Next, as shown in FIG. 19, the control unit 260 positions the support device 230A at a position facing the dissolving port 222B. Furthermore, as shown in FIG. 20, the control unit 260 controls the first cylinder 246 of the target exchanger 240 to move the first slide plate 243 (see FIG. 12) toward the positive side in the Y-axis direction, thereby positioning the support device 230A in front of the dissolving port 222B. Furthermore, the control unit 260 extends the cylinder 272 of the push-out mechanism 270A to press the support device 230A against the dissolving port 222B. At this time, the support device 230B also moves toward the positive side in the Y-axis direction, but the support device 230B is not pressed against any other component. In the following description, this control content will be expressed as "the control unit 260 presses the support device 230A against the dissolving port 222B." Similar expressions are used for this control content and other control content with the same meaning. The control unit 260 controls the dissolving device 220 to supply the dissolving liquid SL to the support device 230A and collect the dissolving liquid SL in which the radioisotope of the solid target 10 has been dissolved. After the collection is completed, the control unit 260 releases the support device 230A from pressing against the dissolving port 222B. Then, the control unit 260 returns the positions of the support devices 230A and 230B to their initial positions.

[0105] 21 , the control unit 260 places the support device 230B at a position facing the irradiation port 212 and presses the support device 230B against the irradiation port 212. The control unit 260 controls the target irradiation device 210 to irradiate the solid target of the support device 230B with the charged particle beam B. When the irradiation is completed, the control unit 260 releases the support device 230B from the pressing against the irradiation port 212.

[0106] Next, as shown in FIG. 22 , the control unit 260 places the support device 230B at a position facing the dissolving port 222B and presses the support device 230B against the dissolving port 222B. The control unit 260 controls the dissolving device 220 to supply a dissolving liquid SL to the support device 230B and recover the dissolving liquid SL in which the radioactive isotopes from the solid targets 10 have been dissolved. Once the recovery is complete, the control unit 260 releases the support device 230B from pressing it against the dissolving port 222B. Then, the control unit 260 returns the positions of the support devices 230A and 230B to their initial positions. This completes the recovery of radioactive isotopes using two solid targets 10.

[0107] Next, an example of the operation for recovering two radioisotopes using two solid targets 10 will be described. Operations common to the above-mentioned operations will be described using common drawings.

[0108] The control unit 260 irradiates the solid target 10 on the support device 230A with a charged particle beam B by performing the operation shown in FIG. 18 . Next, as shown in FIG. 23 , the control unit 260 places the support device 230A at a position facing the dissolving port 222A and presses the support device 230A against the dissolving port 222A. The control unit 260 controls the dissolving device 220 to supply a dissolving liquid SL to the support device 230A and collect the dissolving liquid SL in which the radioactive isotopes of the solid target 10 have been dissolved. After the collection is completed, the control unit 260 releases the support device 230A from pressing it against the dissolving port 222A. Then, the control unit 260 returns the positions of the support devices 230A and 230B to their initial positions.

[0109] Next, the control unit 260 irradiates the solid target 10 of the support device 230B with the charged particle beam B by performing the operation shown in FIG. 21. Next, the control unit 260 recovers radioactive isotopes from the solid target 10 of the support device 230B by performing the operation shown in FIG. 22. At this time, the dissolving port 222B uses a dissolving liquid SL different from that used in the dissolving port 222A. As a result, the radioactive isotopes from the solid target 10 of the support device 230B are recovered with a dissolving liquid SL different from that used for the support device 230A. Then, the control unit 260 returns the positions of the support devices 230A and 230B to their initial positions. This completes the recovery of radioactive isotopes using the two solid targets 10.

[0110] It is also possible to recover one type of radioisotope using one solid target 10. In this case, the support device 230B is omitted from Figures 18 to 20, and only the support device 230A is used to perform the operations shown in Figures 18 to 20.

[0111] As described above, the target irradiation system 200 further includes a target exchanger 240 that transports the solid targets 10, and the target exchanger 240 is capable of supporting a plurality of solid targets 10. In this case, the target exchanger 240 can transport a plurality of solid targets 10 to the irradiation position and the melting position without removing the solid targets 10 along the way. This reduces the impact of radiation exposure due to the removal work.

[0112] For example, after radioisotopes are collected from the solid target 10 of the support device 230A as shown in Figures 18 and 23, processing is performed on the solid target 10 of the support device 230B as shown in Figures 21 and 22 without any particular replacement (removal) work of the solid target 10. In this way, once the solid targets 10 are set for multiple support devices 230, the target irradiation system 200 can automatically perform the switching, irradiation, dissolution, and collection processes of the solid targets 10 multiple times. This significantly reduces the radiation exposure associated with the replacement work of the solid targets 10.

[0113] The target irradiation system 200 further includes a support device 230 that supports the solid target 10, the target irradiation device 210 includes an irradiation port 212 from which a charged particle beam B is emitted, the melting device 220 includes dissolving ports 222A and 222B that supply and recover a dissolving liquid SL, and the support device 230 may be connected to the irradiation port 212 and also to the dissolving ports 222A and 222B. In this case, the support device 230 can be used as both a part of the target irradiation device 210 and a part of the melting device 220.

[0114] The dissolving device 220 may include a plurality of dissolving ports 222A, 222B for supplying and recovering the dissolving solution SL. In this case, the dissolving process for a plurality of radioisotopes can be performed without the need to replace the dissolving ports 222A, 222B.

[0115] [Form 1] A target irradiation system for generating radioactive isotopes of a metal layer by irradiating a solid target having a metal layer with a charged particle beam extracted from a particle accelerator, the system comprising: a target irradiation device that is arranged in a room provided in a building and that holds the solid target at an irradiation position of the charged particle beam to enable irradiation of the solid target with the charged particle beam; a melting device that is disposed in the chamber and melts the radioactive isotope that has adhered to the solid target after irradiation with the charged particle beam by the target irradiation device. Target illumination system. [Form 2] a support for supporting the target irradiation device relative to a floor of the chamber; The melting apparatus is supported relative to the floor by the support. 2. The target illumination system of claim 1. [Form 3] a conveying device that conveys the solid target released from the holding by the target irradiation device to the melting device; 3. The target irradiation system according to claim 1 or 2. [Form 4] a shielding shield provided in the chamber, containing the particle accelerator and the target irradiation device therein, and blocking radiation emitted from the particle accelerator and the target irradiation device; The melting device is provided within the shielding shield. The target irradiation system according to any one of the first to third aspects. [Form 5] a transport device that transports the solid target from the target irradiation device to the melting device; a control unit, The target irradiation system according to any one of the first to fourth aspects, wherein the control unit controls the transport device to transport the solid target held in the target irradiation device to the melting device after the metal layer is irradiated with the charged particle beam. [Form 6] a shielding shield provided in the chamber, containing the particle accelerator and the target irradiation device therein, and blocking radiation emitted from the particle accelerator and the target irradiation device; a housing portion that covers the melting device within the shield; 6. The target irradiation system according to any one of aspects 1 to 5, further comprising: an exhaust unit that exhausts gas from within the container unit to the outside of the shield. [Form 7] a transport device for transporting the solid target; 7. The target irradiation system according to any one of aspects 1 to 6, wherein the transport device is capable of supporting a plurality of the solid targets. [Form 8] a support device for supporting the solid target; the target irradiation device includes an irradiation port from which the charged particle beam is emitted, the dissolving device includes a dissolving port for supplying and recovering a dissolving solution; 8. The target irradiation system according to any one of aspects 1 to 7, wherein the support device is coupled to the irradiation port and also to the dissolution port. [Form 9] 9. The target irradiation system according to any one of aspects 1 to 8, wherein the dissolving device includes a plurality of dissolving ports for supplying and recovering the dissolving liquid. [Form 10] A target irradiation system for generating radioactive isotopes of a metal layer by irradiating a solid target having a metal layer with a charged particle beam extracted from a particle accelerator, the system comprising: a target irradiation device that holds the solid target at an irradiation position of the charged particle beam and enables the solid target to be irradiated with the charged particle beam; a melting device that melts the radioactive isotope attached to the solid target after the irradiation of the charged particle beam by the target irradiation device has been completed, the target irradiation device and the melting device are arranged in the same room in a building. Target illumination system. [Form 11] A method for recovering radioisotopes from a solid target, comprising recovering radioisotopes from a metal layer attached to the solid target, the method comprising: a target irradiation device disposed in a shielded room in a building irradiates the solid target with a charged particle beam to generate the radioisotope in the solid target; transporting the solid target, which has been irradiated with the charged particle beam, to a melting device disposed in the shielding chamber by a transport device capable of transporting the solid target; dissolving the radioisotope attached to the solid target by the dissolving device; A method for recovering radioisotopes from solid targets. [Explanation of symbols]

[0116] 2...cyclotron, 3,200...target irradiation system, 4...shielding shield (support part), 10...solid target, 11...metal layer, 20,210...target irradiation device, 21,220...melting device, 22...transport device, 50...control part, 70...accommodation part, 71...exhaust part, 100...self-shielded cyclotron system, 212...irradiation port, 222A, 222B...melting port, 230, 230A, 230B...support device (target irradiation device, melting device), 240...target exchanger (transport device).

Claims

1. A target irradiation system for generating radioisotopes by irradiating a charged particle beam extracted from an accelerator, comprising: a target irradiation device that holds a solid target at an irradiation position of the charged particle beam and enables the solid target to be irradiated with the charged particle beam; a dissolving device that dissolves, with strong acid, the radioactive isotopes attached to the solid target after the irradiation of the charged particle beam by the target irradiation device has been completed; Equipped with A target irradiation system, comprising: a step of sliding the solid target after irradiation into the melting device.

2. a support portion that supports the target irradiation device; The melting apparatus is supported by the support portion. The target illumination system of claim 1 .

3. a transport device that transports the solid target from the target irradiation device to the melting device; a control unit, 3. The target irradiation system according to claim 1, wherein the control unit controls the transport device to transport the solid target held in the target irradiation device to the melting device after the metal layer of the solid target is irradiated with the charged particle beam.

4. a transport device for transporting the solid target; The target irradiation system according to claim 1 , wherein the transport device is capable of supporting a plurality of the solid targets.

5. A target irradiation system for generating radioisotopes by irradiating a charged particle beam extracted from an accelerator, comprising: a target irradiation device that holds a solid target at an irradiation position of the charged particle beam and enables the solid target to be irradiated with the charged particle beam; a dissolving device that dissolves, with strong acid, the radioactive isotopes attached to the solid target after the irradiation of the charged particle beam by the target irradiation device has been completed; a support device for supporting the solid target; Equipped with Sliding the irradiated solid target into the melting device; the target irradiation device includes an irradiation port from which the charged particle beam is emitted, the dissolving device includes a dissolving port for supplying and recovering a dissolving solution; The support device is coupled to the illumination port and is coupled to the dissolution port.

6. The target irradiation system according to claim 1 , wherein the melting device comprises a plurality of melting ports for supplying and recovering the melting liquid.

7. 7. The target irradiation system according to claim 1, wherein the target irradiation device and the melting device are arranged in the same room in a building.

8. a transport device for transporting the solid target; the transport device includes a transport tray that transports the solid target while placing the solid target thereon; The target irradiation system according to any one of claims 1 to 7, wherein the transport tray is retracted from the melting device when the melting device melts the radioactive isotopes attached to the solid target.

9. The target irradiation system according to any one of claims 1 to 8, wherein the melting device has a main body having an internal space, and the solid target is pressed against the main body to block the internal space, and a melting liquid is supplied into the internal space, thereby dissolving the radioactive isotope attached to the solid target with the melting liquid.

10. a transport device for transporting the solid target; the transport device includes a transport tray that transports the solid target while placing the solid target thereon; The target irradiation system according to claim 1 , wherein the transport tray holds the irradiated solid target and slides it into the melting device.

11. 1. A method for recovering radioisotopes from a solid target, comprising recovering radioisotopes adhering to a solid target having a metal layer, the method comprising: a conveying device capable of conveying the solid target slides the solid target after the irradiation of the charged particle beam to a melting device; dissolving the radioisotope attached to the solid target with a strong acid by the dissolving device; A method for recovering radioisotopes from solid targets.

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