Target irradiation system and method for recovering radioisotope from solid target

Abstract

The invention relates to a target irradiation system and a method for recovering radioisotopes from a solid target. A target irradiation system for irradiating a solid target having a metal layer with a charged particle beam emitted from a particle accelerator to generate a radioisotope of the metal layer, the target irradiation system being provided with: a target irradiation device which is disposed in a room provided in a building and is capable of irradiating the solid target with the charged particle beam by holding the solid target at an irradiation position of the charged particle beam; and a dissolving device which is disposed in the chamber and dissolves the radioisotope adhering to the solid target irradiated by the charged particle beam by the target irradiation device.

Description

[0001] This application is a divisional application of application No. 202080020988.1, application date March 26, 2020, and invention name “Target irradiation system and method for recovering radioactive isotopes from solid targets”. Technical Field

[0002] The present invention relates to a target irradiation system and a method for recovering radioactive isotopes from a solid target. Background Art

[0003] As shown in Patent Document 1, there is known a self-shielded cyclotron system having a self-shielded body, which houses a cyclotron inside and suppresses the release of radiation released from the cyclotron to the outside. In recent years, a device has been developed that obtains solid radioactive isotopes (RI: RadioIsotope) by irradiating a target having a metal layer with a charged particle beam. Such radioactive isotopes are used to manufacture radioactive drugs used in PET examinations (positron emission tomography examinations) in hospitals, etc. For example, in Patent Document 2, a target with a solid radioactive isotope attached is transported to a dissolution device, and the radioactive isotope is dissolved in the dissolution device, thereby recovering the RI.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2000-105293

[0007] Patent Document 2: Japanese Patent Application Publication No. 2014-115229 Summary of the invention

[0008] Technical issues to be solved by the invention

[0009] Here, the target is activated after being irradiated with the charged particle beam, so it is required to take the target out of the irradiation device and quickly dissolve the radioactive isotope in the dissolution device.

[0010] An object of the present invention is to provide a target irradiation system capable of taking out a target from an irradiation device and quickly dissolving a radioactive isotope in a dissolution device, and a method for recovering a radioactive isotope from a solid target.

[0011] Means for solving technical problems

[0012] The target irradiation system involved in the present invention is a system for irradiating a solid target having a metal layer with a charged particle beam emitted from a particle accelerator to generate radioactive isotopes in the metal layer. The target irradiation system comprises: a target irradiation device, which is arranged in a room set up in a building and holds the solid target at an irradiation position of the charged particle beam so that the solid target can be irradiated with the charged particle beam; and a dissolution device, which is arranged in the room and dissolves the radioactive isotopes attached to the solid target that has been irradiated with the charged particle beam by the target irradiation device.

[0013] In the target irradiation system involved in the present invention, the target irradiation device holds the solid target at the irradiation position of the charged particle beam, so that the solid target can be irradiated with the charged particle beam. As a result, radioactive isotopes are formed in the metal layer of the solid target at the position irradiated with the charged particle beam. In addition, the dissolving device dissolves the radioactive isotopes attached to the solid target that has been irradiated with the charged particle beam by the target irradiation device. As a result, the radioactive isotopes can be recovered by recovering the dissolving liquid. Here, the target irradiation device and the dissolving device are arranged in a room set in a building. Therefore, the process of irradiating the solid target with a charged particle beam and the process of recovering the radioactive isotopes by dissolving are both carried out indoors. Therefore, the solid target can be taken out from the target irradiation device and the radioactive isotopes can be quickly dissolved in the dissolving device.

[0014] The target irradiation system further includes a support portion for supporting the target irradiation device on the indoor floor, and the dissolving device can be supported on the floor by the support portion. In this case, since the target irradiation device and the dissolving device are supported by the common support portion, the two can be arranged in close positions.

[0015] The target irradiation system may further include a transport device that transports the solid target whose holding by the target irradiation device is released to the dissolution device. In this case, the solid target can be quickly transported from the target irradiation device to the dissolution device.

[0016] The target irradiation system further includes a shielding protective body, which is arranged indoors and accommodates the particle accelerator and the target irradiation device inside to shield the radiation released from the particle accelerator and the target irradiation device, and the dissolving device can be arranged inside the shielding protective body. In this case, when the solid target is transported from the target irradiation device to the dissolving device, the shielding protective body can shield the radiation.

[0017] The target irradiation system also includes a conveying device and a control unit, wherein the conveying device conveys the solid target from the target irradiation device to the dissolution device, and the control unit can control the conveying device so that after the metal layer is irradiated with a charged particle beam, the solid target dissolution device held in the target irradiation device is conveyed. Thus, the control unit automatically conveys the solid target based on the conveying device. Thus, the radiation exposure to the staff can be further suppressed. In addition, the control unit automatically conveys the solid target, thereby shortening the working time.

[0018] The target irradiation system also includes a shielding protective body, which is arranged indoors and contains a particle accelerator and a target irradiation device inside to shield the radiation released from the particle accelerator and the target irradiation device. The target irradiation system may include: a housing portion, which covers the dissolving device in the shielding protective body; and an exhaust portion, which discharges the gas in the housing portion to the outside of the shielding protective body. At this time, when the dissolved liquid in the dissolving device is vaporized, the gas is suppressed from diffusing into the shielding protective body by the housing portion. In addition, the gas in the housing portion can be discharged to the outside of the shielding protective body through the exhaust portion. As a result, other equipment in the shielding protective body can be suppressed from being corroded by the gas.

[0019] The target irradiation system further includes a conveying device for conveying solid targets, and the conveying device can support a plurality of solid targets. In this case, the conveying device can convey a plurality of solid targets to the irradiation position and the dissolution position without unloading the solid targets during the process. Thus, the influence of radiation exposure caused by unloading can be reduced.

[0020] The target irradiation system further includes a support device for supporting the solid target, the target irradiation device includes an irradiation port for emitting a charged particle beam, the dissolution device includes a dissolution port for supplying and recovering a dissolving liquid, and the support device can be connected to the irradiation port and to the dissolution port. In this case, the support device can serve as both a part of the target irradiation device and a part of the dissolution device.

[0021] The dissolution device may be provided with a plurality of dissolution ports for supplying and recovering the dissolution liquid. In this case, the dissolution process of radioactive isotopes of a plurality of nuclides can be performed without replacing the dissolution ports.

[0022] The target irradiation system irradiates a solid target having a metal layer with a charged particle beam emitted from a particle accelerator to generate radioactive isotopes of the metal layer, and the target irradiation system comprises: a target irradiation device that holds the solid target at an irradiation position of the charged particle beam so that the solid target can be irradiated with the charged particle beam; and a dissolving device that dissolves the radioactive isotopes attached to the solid target that has been irradiated with the charged particle beam by the target irradiation device, and the target irradiation device and the dissolving device are arranged in the same room set in a building. According to the target irradiation system, the same effect as the above-mentioned target irradiation system can be obtained.

[0023] A method for recovering radioactive isotopes from a solid target is to recover radioactive isotopes attached to a metal layer on a solid target having a metal layer. In the method for recovering radioactive isotopes from a solid target, a charged particle beam is irradiated on the solid target by a target irradiation device arranged in a shielded room of a building so that the solid target generates radioactive isotopes. The solid target irradiated with the charged particle beam is transported to a dissolving device arranged in the shielded room by a conveying device capable of conveying the solid target, and the radioactive isotopes attached to the solid target are dissolved by the dissolving device. According to the recovery method, the process of irradiating the solid target with a charged particle beam, the process of conveying the solid target, and the process of recovering the radioactive isotopes by dissolving are all carried out in the shielded room. Therefore, the solid target can be taken out from the target irradiation device and the radioactive isotopes can be quickly dissolved in the dissolving device. Moreover, radiation can be shielded in each process.

[0024] Effects of the Invention

[0025] According to the present invention, it is possible to provide a target irradiation system capable of taking out a target from an irradiation device and rapidly dissolving a radioactive isotope in a dissolution device, and a method for recovering a radioactive isotope from a solid target. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic configuration diagram showing a self-shielded cyclotron system including a target irradiation system according to one embodiment of the present invention.

[0027] Figure 2 It is a three-dimensional image of a solid target.

[0028] Figure 3 It is an enlarged view of the target irradiation system.

[0029] Figure 4 It is a flowchart showing the processing contents of the control unit.

[0030] Figure 5 It is an enlarged view showing the operation of the target irradiation system.

[0031] Figure 6It is an enlarged view showing the operation of the target irradiation system.

[0032] Figure 7 It is an enlarged view showing the operation of the target irradiation system.

[0033] Figure 8 It is an enlarged view showing the operation of the target irradiation system.

[0034] Fig. 9 It is an enlarged view showing the operation of the target irradiation system.

[0035] Fig.10 It is an enlarged view showing a self-shielded cyclotron including a target irradiation system according to a modification.

[0036] Fig.11 It is a conceptual configuration diagram showing a target irradiation system according to a modification example.

[0037] Fig.12 It is a schematic configuration diagram showing a target irradiation system according to a modified example.

[0038] Fig.13 Yes means Fig.12 A schematic diagram of the main parts of the target irradiation system is shown.

[0039] Fig.14 It is a perspective view showing an example of a specific structure of a target exchanger.

[0040] Fig.15 It is a cross-sectional view showing a state where the support device is pressed against the irradiation port.

[0041] Fig.16 It is a cross-sectional view showing a state where the support device is pressed against the dissolution port.

[0042] Fig.17 It is the front view of the dissolution port.

[0043] Fig.18 This is a schematic diagram showing the operation of the target irradiation system.

[0044] Fig.19 This is a schematic diagram showing the operation of the target irradiation system.

[0045] Fig. 20 This is a schematic diagram showing the operation of the target irradiation system.

[0046] Fig.21 This is a schematic diagram showing the operation of the target irradiation system.

[0047] Fig. 22 This is a schematic diagram showing the operation of the target irradiation system.

[0048] Fig.23This is a schematic diagram showing the operation of the target irradiation system. DETAILED DESCRIPTION

[0049] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the same reference numerals are given to the same or corresponding parts in each figure, and repeated description is omitted.

[0050] like Figure 1 As shown, the self-shielded cyclotron system 100 is a system installed inside a building 150. The self-shielded cyclotron system 100 involved in this embodiment is a system for producing radioactive isotopes (hereinafter sometimes referred to as RI) using a charged particle beam. The self-shielded cyclotron system 100 can be used as a cyclotron for PET, for example, and the RI produced in the system is used to produce radioactive drugs (including radiopharmaceuticals) as radioactive isotope-labeled compounds (RI compounds). As radioactive isotope-labeled compounds used in PET examinations (positron emission tomography examinations) in hospitals, etc., there are 18 F-FLT (fluorothymidine), 18 F-FMISO (Fluoronitriloimidazole) and 11 C-raclopride, etc.

[0051] The self-shielded cyclotron system 100 includes a cyclotron 2 (particle accelerator), a target irradiation system 3, and a shielding protection body 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 house covered with concrete (shielding wall). Therefore, by using the self-shielded cyclotron system 100, the user can obtain radioactive isotopes on the spot in the building.

[0052] The cyclotron 2 is an accelerator for emitting 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 surrounding the pair of magnetic poles and the vacuum box. Parts of a pair of magnetic poles face each other at a predetermined interval on the main surface of the vacuum box. In the gap between the pair of magnetic poles, the charged particles are multiply accelerated. As charged particles, for example, protons, heavy particles (heavy ions), etc. can be cited. In the present embodiment, the cyclotron 2 has a plurality of ports 2a for emitting charged particle beams. A target irradiation device 20 described later is formed in one of the plurality of ports 2a. The cyclotron 2 adjusts the trajectory of the charged particle beam in the acceleration space and takes out the charged particle beam from the desired port 2a.

[0053] The shielding protective body 4 is arranged indoors (inside the cyclotron room 152), and the cyclotron 2 and the target irradiation device 20 described later are contained inside to shield the radiation released from the cyclotron 2 and the target irradiation device 20 described later. The shielding protective body 4 is arranged inside the building, and the cyclotron 2 is contained inside to suppress the radiation released from the cyclotron 2 from being released into the cyclotron room 152. The shielding protective body 4 can shield the radiation in all directions by covering the cyclotron 2 in all directions. In the present embodiment, the shielding protective body 4 has a hexahedral box-shaped structure, but the shape is not particularly limited. The shielding protective body 4 separates the internal space of the building 150 (cyclotron room 152) and the internal space 120 of the self-shielded cyclotron system 100. The internal space of the building 150 can be configured as a space where other equipment or staff can pass. Therefore, the system in which only the cyclotron 2 is arranged in the room of the building is different from the self-shielded cyclotron system 100 of the present embodiment, and the walls constituting the surroundings of the room of the building do not correspond to the shielding protection body 4. The walls of the shielding protection body 4 are made of materials such as polyethylene, iron, lead, and heavy concrete. In addition to the cyclotron 2, a vacuum pump, wiring, etc. for operating the cyclotron 2 are arranged in the shielding protection body 4. In addition, the components of the target irradiation system 3 are also arranged in the shielding protection body 4. Therefore, the shielding protection body 4 functions as a support portion for supporting the target irradiation device 20 described later on the floor 151 of the cyclotron room 152. The dissolution device 21 described later is supported on the floor 151 by the shielding protection body 4 that functions as a support portion. According to the above-mentioned structure, the target irradiation device 20 described later and the dissolution device 21 described later are arranged in the same room (inside the cyclotron room 152) set in the building 150.

[0054] The target irradiation system 3 is a part that irradiates the solid target 10 with a charged particle beam and dissolves and recovers the radioactive isotopes generated by the irradiation. The target irradiation system 3 is formed near the outer periphery of the cyclotron 2 and is arranged in the shielding protection body 4. The solution containing the radioactive isotope obtained by the target irradiation system 3 is transported to a device 160 such as a refining device for refining the radioactive isotope in the solution and a synthesis device for synthesizing a drug via a transport pipe 161.

[0055] refer to Figure 2 , the solid target 10 is described. The solid target 10 includes a target substrate 13 and a metal layer 11. Specifically, Figure 2As shown, the solid target 10 forms a metal layer 11 as a target material on a target substrate 13 composed of a metal plate. In addition, the metal layer 11 is not limited to a high-purity metal layer, and can also be a metal oxide layer. The target substrate 13 is set in the device, and the charged particle beam B is irradiated to the metal layer 11, 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. As the material of the target substrate 13, a material that is insoluble in the dissolving solution is used, for example, Au, Pt, etc. Figure 2 The target substrate 13 shown is formed in a disk shape, but the shape and thickness are not particularly limited. As the target material, that is, the material of the metal layer 11, for example, 64 You, 89 Y. 100 Mo, 68 As the radioactive isotope 12 generated in response to the metal layer 11, there are 64 Cu, 89 Zr, 99m Tc, 68 Ga, etc. The metal layer 11 is formed by performing an electroplating process on the surface 10 a of the target substrate 13 . In addition, the process is not limited to the electroplating process, and a plate-shaped metal layer may be attached to the target substrate 13 . Figure 2 The metal layer 11 shown is formed in a circular shape at the center of the target substrate 13, but the shape and position are not particularly limited. In addition, when the charged particle beam B is irradiated on the metal layer 11, cooling water or the like can be supplied to the back side 10b of the target substrate 13. Thus, the heat generated by the metal layer 11 (and the target substrate 13) caused by the irradiation of the charged particle beam B can be absorbed by the cooling water or the like.

[0056] Next, refer to Figure 3 , the structure of the target irradiation system 3 is described in detail. The target irradiation system 3 irradiates the solid target 10 having the metal layer 11 with the charged particle beam emitted from the cyclotron 2 to generate the radioactive isotope of the metal layer 11. The target irradiation system 3 includes: a target irradiation device 20, a dissolving device 21, a conveying device 22 and a control unit 50.

[0057] The target irradiation device 20 is a device that is arranged in a room (inside the cyclotron room 152) provided in the building 150, and holds the solid target 10 at the irradiation position of the charged particle beam B, so that the solid target 10 can be irradiated with the charged particle beam B. The target irradiation device 20 holds the solid target 10 having the metal layer 11 at the irradiation position of the charged particle beam B. And, after the irradiation of the solid target 10 with the charged particle beam B is completed, the target irradiation device 20 releases the holding of the solid target 10. 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 clamping the solid target 10 with the fixed unit 23 and the movable unit 24. Both the fixed unit 23 and the movable unit 24 are accommodated in the shielding protective body 4.

[0058] The fixing unit 23 is a cylindrical component fixed to the outer periphery of the cyclotron 2. The fixing 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 fixing 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 in a manner extending along the irradiation axis BL with the irradiation axis BL as the center line. The fixing unit 23 and the internal space 26 are arranged to be inclined downward relative to the horizontal direction.

[0059] The fixed unit 23 has a surface extending in the horizontal direction at the lower end side as an opposing surface 23a opposed to 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 component 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 component, thereby also playing the role of a sealing surface for sealing the solid target 10. In the present embodiment, on the opposing surface 23a, the portion where the internal space 26 opens (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 is held in such a manner that the metal layer 11 in the solid target 10 is arranged at the opening of the internal space 26.

[0060] The fixing unit 23 includes a vacuum foil 25 at a midway position of the internal space 26. The vacuum foil 25 keeps a region on the upstream side of the vacuum foil 25 in the internal space 26 in a vacuum state.

[0061] The fixing unit 23 has a charged particle beam B arranged at an irradiation position and a flow path 27 for blowing a gas such as helium to the vacuum foil 25. The flow path 27 has a main flow path 27a and branch flow paths 27b and 27c branched from the main flow path 27a. The branch flow path 27b extends toward the vacuum foil 25 and blows a gas to the vacuum foil 25. The branch flow path 27c extends toward the irradiation position RP of the solid target 10 and blows a gas to the held solid target 10.

[0062] The movable unit 24 moves forward and backward in the vertical direction relative to the fixed unit 23. When the solid target 10 is placed on the conveying tray 60, the movable unit 24 is arranged at a position separated downward from the fixed unit 23. When the solid target 10 is held at the irradiation position RP, the movable unit 24 is arranged at a position where the solid target 10 is sandwiched between the movable unit 24 and the fixed unit 23 (refer to Figure 5 ).

[0063] The movable unit 24 has a cylindrical shape extending in the vertical direction. The movable unit 24 is connected to a driving mechanism 28 that moves in the vertical direction at a part of the outer peripheral surface. A small diameter portion 29 protruding upward is formed at the upper end of the movable unit 24. The diameter of the small diameter portion 29 is at least smaller than the diameter of the inner peripheral portion of the conveying tray 60 described later. Thus, the small diameter portion 29 passes through the through hole on the inner peripheral side of the conveying tray 60 and abuts against the solid target 10, pressing the solid target 10 against the fixed unit 23 above.

[0064] The movable unit 24 has a surface extending in the horizontal direction as an opposing surface 24a that is opposed to the opposing surface 23a of the fixed unit 23 on the upper end side of the small diameter portion 29. 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, thereby also playing the role of a sealing surface for sealing the solid target 10. When the target irradiation device 20 holds the solid target 10, the opposing surface 23a and the opposing surface 24a clamp the solid target 10 (refer to Figure 5 ).

[0065] The movable unit 24 has an internal space 31 opened on the facing surface 24a. The internal space 31 is a space for storing a cooling medium for cooling the solid target 10. The internal space 31 is connected to a supply pipe 32 for supplying the cooling medium and a discharge pipe 33 for discharging the cooling medium.

[0066] The dissolving device 21 is a device that is arranged in a room (inside the cyclotron room 152) and dissolves the radioactive isotope attached to the solid target 10 that has been irradiated with the charged particle beam B by the target irradiation device 20. The dissolving device 21 dissolves the metal layer 11 containing the radioactive isotope in the solid target 10. The dissolving device 21 includes a fixed unit 40 and a movable unit 41. The dissolving device 21 is clamped by the fixed unit 40 and the movable unit 41 to hold the solid target 10. While holding the solid target 10, the dissolving device 21 supplies a dissolving liquid to at least the metal layer 11, dissolves the metal of the metal layer 11 containing the radioactive isotope in the dissolving liquid, and recovers the dissolving liquid together with the radioactive isotope. As the dissolving liquid, hydrochloric acid, nitric acid, etc. can be used. The fixed unit 40 and the movable unit 41 are contained in the shielding protective body 4.

[0067] The fixed unit 40 is arranged at a position separated from the fixed unit 23 of the target irradiation device 20 to the opposite side of the cyclotron 2. The fixed unit 40 includes: a cylindrical main body 48 extending in the up-down direction and a support part 49 supporting the main body 48 on the outer peripheral side. The main body 48 has a surface extending in the horizontal direction as an opposing surface 40a opposing the movable unit 41 at the lower end side. The solid target 10 is held at the position of the opposing surface 40a. A sealing component 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 component, thereby also playing a role as a sealing surface for sealing the solid target 10. The solid target 10 is held at the position of the opposing surface 40a.

[0068] The main body 48 has an internal space 42 opened on the facing surface 40a. The internal space 42 is a dissolving tank for storing a dissolving liquid used to dissolve the metal layer 11 of the solid target 10. In the internal space 42, a supply suction pipe 43 for supplying the dissolving liquid and a suction pipe 44 for sucking the dissolving liquid and the gas in the internal space 42 are connected. The diameter of the internal space 42 opened on 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. In addition, although the diameter of the facing surface 40a itself is not particularly limited, in this embodiment, it is smaller than the diameter of the solid target 10.

[0069] The support portion 49 is a cylindrical member having an end surface wall extending radially outward from the outer peripheral surface of the main body portion 48. The support portion 49 has a through hole 49a for inserting the main body portion 48 at a central position. A flange portion is formed near the upper end portion of the main body portion 48. The flange portion is engaged with the upper edge portion of the through hole 49a of the main body portion 48.

[0070] The movable unit 41 moves forward and backward in the vertical direction relative to the fixed unit 40. When the solid target 10 is mounted on the fixed unit 40, the movable unit 41 is arranged at a position separated downward from the fixed unit 40. When the metal layer 11 of the solid target 10 is dissolved in the dissolution device 21, the movable unit 41 is arranged at a position where the solid target 10 is sandwiched between the fixed unit 40 (refer to Fig. 9 ).

[0071] The movable unit 41 includes a main body 46 and a receiving plate 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 peripheral surface of the main body 46 is connected to a driving mechanism (not shown) that moves in the vertical direction. A groove structure for supporting the receiving plate 47 is formed at the upper end of the main body 46.

[0072] The receiving plate 47 includes a bottom wall 47a extending in the horizontal direction at the upper end of the main body 46 and a side wall 47b rising upward from the outer peripheral edge of the bottom wall 47a. The bottom wall 47a has a surface extending in the horizontal direction as an opposing surface 41a opposing the opposing surface 40a of the fixing unit 40. The opposing surface 41a contacts the solid target 10. When the dissolving device 21 holds the solid target 10, the opposing surface 40a and the opposing surface 41a sandwich the solid target 10 (see Fig. 9 ). The inner diameter of the side wall portion 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 portion 47b is arranged at a position higher than the solid target 10. Therefore, when the dissolving liquid leaks from the internal space 42 when the metal layer 11 of the solid target 10 is dissolved, the receiving plate portion 47 receives the dissolving liquid. In addition, the bottom surface side of the bottom wall portion 47a has a concave-convex structure for fitting with the groove structure of the main body portion 46.

[0073] In the dissolving device 21, the main body 48 and the receiving plate 47 in contact with the dissolving liquid are constituted as disposable devices that can be replaced. That is, the main body 48 is installed on the supporting part 49 in a manner that can be loaded and unloaded. The receiving plate 47 is installed on the main body 46 in a manner that can be loaded and unloaded. Here, the so-called "loading and unloading" means that even if the installation is completed temporarily, the staff can also easily remove the installation method through the usual maintenance work. For example, as a mounting structure that can be loaded and unloaded, a structure that is installed by bolting, or a structure that is installed by fitting or snapping at a strength that does not separate during dissolution can be cited. For example, fixed structures such as welding or welding do not belong to the method that can be loaded and unloaded. The material of the replaceable main body 48 and the receiving plate 47, for example, a material with high acid resistance such as Teflon (registered trademark) can be used.

[0074] The conveying device 22 is a device for conveying the solid target 10 whose holding by the target irradiation device 20 is released to the dissolution device 21. The conveying device 22 conveys the solid target 10 from the target irradiation device 20 to the dissolution device 21. The conveying device 22 is arranged in the shielding protective body 4. The conveying device 22 includes: a conveying tray 60 for conveying in a state where the solid target 10 is placed, and a conveying driving unit 61 for driving the conveying tray 60. The conveying tray 60 is an annular member having a supporting portion for supporting the solid target 10 on the upper surface side. The conveying tray 60 has a groove portion formed throughout the inner peripheral side edge portion of the upper surface, and the outer peripheral edge of the lower surface side of the solid target 10 is mounted on the groove portion. The conveying driving unit 61 is composed of a combination of a driving source and a driving force transmission mechanism not shown. The conveying driving unit 61 conveys the solid target 10 to the position of the dissolution device 21 by moving the conveying tray 60 from the position of the target irradiation device 20 to the horizontal direction at least when the solid target 10 irradiated with the charged particle beam is conveyed to the dissolution device 21. The conveying drive unit 61 conveys the conveying 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 dissolving device 21. In addition, the conveying drive unit 61 can be constructed by using a known driving source such as a rotary motor and a linear motor and a driving force transmission mechanism such as a gear and a rod. The conveying drive unit 61 can be any structure as long as it is configured to avoid interference with other components and can perform the desired action. In addition, the position of the conveying tray 60 in each stage will be described in detail when explaining the later-described action.

[0075] The control unit 50 controls the self-shielded cyclotron system 100. The control unit 50 is composed of a CPU, a RAM, a ROM, an input / output interface, etc. The control unit 50 determines the control content according to the detection signals from each sensor in the device and the program stored in the ROM, and controls each component in the self-shielded cyclotron system 100. In addition, the control unit 50 may not be composed of one processing device, but may be composed of a plurality of processing devices. The control unit 50 may be arranged inside the shielding protective body 4, or may be arranged outside the shielding protective body 4.

[0076] The control unit 50 includes an irradiation control unit 51, a holding control unit 52, a dissolution control unit 53, and a transport control unit 54. The irradiation control unit 51 mainly controls the cyclotron 2, and controls the operation related to 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 the operation related to holding the solid target 10 by the target irradiation device 20. The dissolution control unit 53 mainly controls the dissolution device 21, and controls the operation related to dissolving the metal layer 11 of the solid target 10. The transport control unit 54 mainly controls the transport device 22, and controls the operation related to transporting the solid target 10. The transport control unit 54 controls the transport device 22 so that after irradiating the metal layer 11 with the charged particle beam B, the solid target 10 held in the target irradiation device 20 is transported to the dissolution device 21.

[0077] Next, refer to Figure 3 to Figure 9 , the operation of the target irradiation system 3 will be described together with the content of the control processing performed by the control unit 50. Figure 4 2 is a flowchart showing the content of the control processing by the control unit 50 . Figures 4 to 9 3 is a diagram showing the state of the target irradiation system 3 at each stage of the operation. Figures 4 to 9 In the figure, the control unit 50 and the conveying drive unit 61 are omitted. In addition, symbols not used in the description may be appropriately omitted.

[0078] like Figure 4 As shown in FIG. 1 , 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 arranges the target irradiation device 20, the dissolution device 21, and the conveying device 22 in the initial state. The control unit 50 sets the target irradiation system 3 to the initial state by driving the driving units of each component. Figure 3 The state shown in FIG. 1 is shown in FIG. 2 . In this state, the movable unit 24 is arranged at a position separated from the fixed unit 23 downward. The movable unit 41 is arranged at a position separated from the fixed unit 40 downward. The conveying tray 60 is arranged at a position separated from the fixed unit 23 downward 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, even if the conveying tray 60 moves in the horizontal direction, it will not interfere with each unit 23, 24, 40, 41. The control unit 50 can notify the staff of the state that the solid target 10 can be set through a monitor or the like. If it is detected that the staff has placed the solid target 10 on the conveying tray 60, the control unit 50 understands that the setting of the solid target 10 is completed. The control unit 50 can detect that the setting of the solid target 10 is completed through the detection of the sensor or the input of the staff.

[0079] 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: Figure 4 In S20, the holding control unit 52 of the control unit 50 controls the driving mechanism 28 of the movable unit 24 to move the movable unit 24 upward. Figure 5 As shown in FIG. 1 , the solid target 10 is sandwiched by the fixed unit 23 and the movable unit 24 at the irradiation position RP. In addition, while the movable unit 24 is moving upward, the solid target 10 placed on the conveying tray 60 is supported by the movable unit 24 that passes through the through hole of the conveying tray 60 from below. At this time, the conveying tray 60 may be raised while being supported by the movable unit 24. Alternatively, the conveying tray 60 may be driven so as to be raised together with the movable unit 24.

[0080] Next, the control unit 50 performs a process of irradiating the solid target 10 with the charged particle beam B (step S30: Figure 4 ). In S30, the irradiation control unit 51 of the control unit 50 irradiates the solid target 10 with the charged particle beam B by controlling the cyclotron 2. At this time, the holding control unit 52 controls the flow path system so that helium gas or the like is blown from the flow path 27 of the fixing unit 23 to the solid target 10 and the vacuum foil 25. In addition, the holding control unit 52 controls the piping system of the supply pipe 32 and the exhaust pipe 33 so that the cooling medium flows into the internal space 31 to cool the solid target 10.

[0081] When the process of S30 is completed, the holding control unit 52 of the control unit 50 controls the driving mechanism 28 of the movable unit 24 to move the movable unit 24 downward. Figure 6 As shown in FIG. 1 , the movable unit 24 returns to the position of the initial state. Also, the transport tray 60 also returns to the position of the reference height with the solid target 10 placed thereon.

[0082] Next, the control unit 50 performs a process of transporting the solid target 10 from the target irradiation device 20 to the dissolution device 21 (step S40: Figure 4 ) In S40, the conveying control unit 54 of the control unit 50 controls the conveying drive unit 61 of the conveying device 22 (reference Figure 3 ) so that the conveying tray 60 is horizontally moved from the target irradiation device 20 to the position of the dissolution device 21. Figure 7 As shown, the conveying tray 60 is arranged between the fixed unit 40 and the movable unit 41 while maintaining the position of the reference height in the height direction. Thus, the solid target 10 is arranged at a position facing the facing surface 40a opened in the internal space 42 on the lower side.

[0083] Next, the control unit 50 performs a process of placing the solid target 10 in the dissolution device 21 (step S50: Figure 4 ). In S50, if Figure 8 As shown, the dissolution control unit 53 of the control unit 50 controls the piping system of the suction pipe 44 to adsorb the solid target 10 to the opposing surface 40a through the internal space 42. In addition, before the solid target 10 is adsorbed, the solid target 10 is pressed against the opposing surface 40a of the main body 48 by the rise of the conveying tray 60. As a result, the internal space is sealed in a state where an O-ring (not shown) provided between the solid target 10 and the main body 48 is flattened. Thereafter, the conveying control unit 54 controls the conveying drive unit 61 (refer to Figure 3 ), the conveying tray 60 is moved to the position on the target irradiation device 20 side. Thus, interference between the conveying tray 60 and the movable unit 41 is avoided.

[0084] In S50, the dissolution control unit 53 controls the driving unit of the movable unit 41 to move the movable unit 41 upward. Fig. 9 As shown, the solid target 10 is sandwiched between the facing surface 40a of the fixed unit 40 and the facing surface 41a of the movable unit 41. At this time, the solid target 10 is pressed against the main body 48 from above while being accommodated in the receiving plate 47.

[0085] Next, the control unit 50 performs a process of dissolving the metal layer 11 of the solid target 10 in the dissolution device 21 to recover the radioactive isotope contained in the metal layer 11 (step S60: Figure 4 In S60, the dissolution control unit 53 of the control unit 50 controls the piping system of the supply suction pipe 43 to supply the dissolving liquid SL from the supply suction pipe 43 to the internal space 42. In addition, the dissolution control unit 53 controls the piping system of the suction pipe 44 to suck in and recover the dissolving liquid SL in which the radioactive isotope has been dissolved through the supply suction pipe 43. As described above, Figure 4 After the recovery of the radioactive isotope is completed, the worker removes the solid target 10 together with the main body 48 and the receiving plate 47 and moves them out of the shielding protective body 4 .

[0086] like Figure 1As shown, the solution SL in which the radioactive isotope is dissolved is discharged to the outside of the shielding protective body 4 and transported to a refining device for refining the radioactive isotope in the solution SL, or a synthesis device for synthesizing a drug, etc. 160. The refining device or the synthesis device can be arranged in the same building 150, or in different buildings (facilities). In the case of transporting the solution SL to the synthesis device, etc. in the same building 150, the solution SL is transported to the synthesis device, etc. through a transport pipe 161 connected to the supply suction pipe 43. Since radiation is released from the solution SL, the transport pipe 161 is covered by the shielding protective body, or passes through the shielding wall (floor or wall) of the building 150. In the case of transporting the solution SL to different buildings, the recovered solution SL is stored in a shielding box (a box that suppresses the release of radiation to the outside, such as a lead box), and is transported together with the shielding box by a car, etc.

[0087] Next, the effects of the target irradiation system 3 according to the present embodiment will be described.

[0088] The target irradiation system 3 involved in this embodiment irradiates the solid target 10 having a metal layer 11 with the charged particle beam B emitted from the cyclotron 2 to generate radioactive isotopes of the metal layer 11. The target irradiation system 3 comprises: a target irradiation device 20, which is arranged in a cyclotron chamber 152 set in a building 150, and holds the solid target 10 at the irradiation position of the charged particle beam B, so that the solid target 10 can be irradiated with the charged particle beam B; and a dissolution device 21, which is arranged in the cyclotron chamber 152, and dissolves the radioactive isotopes attached to the solid target 10 that has been irradiated with the charged particle beam B by the target irradiation device 20.

[0089] In the target irradiation system 3, the target irradiation device 20 is to hold the solid target 10 at the irradiation position of the charged particle beam B, so that the solid target 10 can be irradiated with the charged particle beam B. As a result, in the metal layer 11 of the solid target 10, a radioactive isotope is formed at the portion irradiated with the charged particle beam B. In addition, the dissolving device 21 dissolves the radioactive isotope attached to the solid target 10 that has been irradiated with the charged particle beam B by the target irradiation device 20. As a result, the radioactive isotope can be recovered by recovering the dissolving liquid. Here, the target irradiation device 20 and the dissolving device 21 are arranged in a cyclotron chamber 152 set in a building 150. Therefore, the process of irradiating the solid target 10 with a charged particle beam and the process of recovering the radioactive isotope by dissolving are both performed in the cyclotron chamber 152. Therefore, the solid target 10 can be taken out from the target irradiation device 20 and the radioactive isotope can be quickly dissolved in the dissolving device 21.

[0090] The target irradiation system 3 further includes a shielding protection body 4, which serves as a support portion to support the target irradiation device 20 on the floor 151 of the cyclotron chamber 152, and the dissolution device 21 is supported on the floor 151 by the support portion. At this time, the target irradiation device 20 and the dissolution device 21 are supported by a common support portion, so the two devices can be arranged at close positions.

[0091] The target irradiation system 3 further includes a transport device 22 that transports the solid target 10 released from the holding by the target irradiation device 20 to the dissolution device 21. In this case, the solid target 10 can be quickly transported from the target irradiation device 20 to the dissolution device 21.

[0092] The target irradiation system 3 further comprises: a shielding protective body 4, which is arranged in the cyclotron chamber 152 and accommodates the cyclotron 2 and the target irradiation device 20 therein to shield the radiation emitted from the cyclotron 2 and the target irradiation device 20, and the dissolving device 21 is arranged in the shielding protective body 4. At this time, the shielding protective body 4 can shield the radiation when the solid target 10 is transported from the target irradiation device 20 to the dissolving device 21.

[0093] The target irradiation system 3 further includes a conveying device 22 and a control unit 50. The conveying device 22 conveys the solid target 10 from the target irradiation device 20 to the dissolution device 21. The control unit 50 controls the conveying device 22 so that after the metal layer 11 is irradiated with the charged particle beam B, the solid target 10 held in the target irradiation device 20 is conveyed to the dissolution device 21. Thus, the conveying device 22 conveys the solid target 10 automatically through the control unit 50. Thus, the radiation exposure to the workers can be further suppressed. In addition, the control unit 50 automatically conveys the solid target 10, thereby shortening the working time.

[0094] The target irradiation system 3 irradiates the solid target 10 having the metal layer 11 with the charged particle beam B emitted from the cyclotron 2 to generate the radioactive isotope of the metal layer 11, and the target irradiation system 3 comprises: a target irradiation device 20, which holds the solid target 10 at the irradiation position of the charged particle beam B so that the solid target 10 can be irradiated with the charged particle beam B; and a dissolving device 21, which dissolves the radioactive isotope attached to the solid target 10 that has been irradiated with the charged particle beam B by the target irradiation device 20, and the target irradiation device 20 and the dissolving device 21 are arranged in the same cyclotron room 152 installed in the building 150. According to the target irradiation system 3, the same effect as described above can be obtained.

[0095] A method for recovering radioactive isotopes from a solid target 10 is to recover radioactive isotopes attached to a metal layer 11 on a solid target 10 having a metal layer 11. In the method for recovering radioactive isotopes from a solid target 10, a target irradiation device 20 disposed in a shielded room of a building 150 irradiates the solid target 10 with a charged particle beam B to generate radioactive isotopes on the solid target 10, and a transport device 22 capable of transporting the solid target 10 transports the solid target 10, after which the irradiation with the charged particle beam B is completed, to a dissolution device 21 disposed in the shielded room, and the radioactive isotopes attached to the solid target 10 are dissolved by the dissolution device 21. According to the recovery method, the steps of irradiating the solid target 10 with the charged particle beam B, transporting the solid target 10, and recovering the radioactive isotopes by dissolution are all performed in the shielded room. Therefore, the solid target can be taken out from the target irradiation device 20 and the radioactive isotopes can be quickly dissolved in the dissolution device 21. Furthermore, radiation can be shielded in each process.

[0096] In the self-shielded cyclotron system 100 involved in the present embodiment, the target irradiation device 20 holds the target having the metal layer 11 at the irradiation position RP of the charged particle beam B. Therefore, the charged particle beam B is irradiated to the solid target 10 held by the target irradiation device 20. As a result, in the metal layer 11 of the solid target 10, the radioactive isotope 12 is formed at the portion irradiated by the charged particle beam B. In addition, the dissolving device 21 is provided with a dissolving device that dissolves the metal layer 11 containing the radioactive isotope in the solid target 10. As a result, the radioactive isotope can be recovered by recovering the dissolving liquid. The transport device 22 transports the solid target 10 from the target irradiation device 20 that irradiates the solid target 10 with the charged particle beam B to the dissolving device 21 that recovers the radioactive isotope. Here, the target irradiation device 20, the dissolving device 21 and the transport device 22 are arranged in the shielding protective body 4. Therefore, the process of irradiating the solid target 10 with the charged particle beam B, the process of recovering the radioactive isotope by dissolution, and the process of transporting the target between the two processes are all performed in the shielding protective body 4. Therefore, in each process, the radiation released from the solid target 10 after the charged particle beam irradiation is blocked by the shielding body. As described above, the safety of radiation exposure when obtaining radioactive isotopes can be further improved.

[0097] The self-shielded cyclotron system 100 further includes a control unit 50, which can control the conveying device 22 so that after the metal layer 11 is irradiated with the charged particle beam B, the solid target 10 held in the target irradiation device 20 is conveyed to the dissolution device 21. Thus, the conveying device 22 automatically conveys the solid target 10 through the control unit 50. Thus, the safety of radiation exposure can be further improved. In addition, the control unit 50 automatically conveys the solid target 10, thereby shortening the working time.

[0098] The present invention is not limited to the above-described embodiment, and various modifications as described below can be made without departing from the gist of the present invention.

[0099] For example, you can use Fig.10 structure. Fig.10 The self-shielded cyclotron system shown may include: a housing 70 that covers the dissolution device 21 in the shielding protective body 4; and an exhaust portion 71 that discharges the gas in the housing 70 to the outside of the shielding protective body 4. The housing 70 covers only the dissolution device 21 but does not cover the target irradiation device 20. In addition, an opening 70a may be formed in the housing 70 at a location through which the conveying tray passes. In addition, the opening 70a may be closed when the conveying tray does not pass through. Furthermore, the exhaust portion 71 may include an exhaust pipe that passes through the shielding protective body 4 from the housing 70 and is connected to the outside of the shielding protective body 4. The exhaust portion 71 may include a pump or the like provided on the exhaust pipe.

[0100] Thus, when the solution in the dissolving device 21 is gasified, the gas can be prevented from diffusing into the shielding body 4 by the container 70. Furthermore, the gas in the container 70 can be discharged to the outside of the shielding body 4 by the exhaust portion 71. Thus, other equipment in the shielding body 4 can be prevented from being corroded by the gas.

[0101] Furthermore, the structure of the target irradiation system shown in the above-mentioned embodiments is only an example, and the shape and arrangement can be appropriately changed within the scope of the present invention. For example, the transport device can use an arm-shaped gripper for gripping the target instead of the transport tray.

[0102] In addition, the transport device automatically transports the target through the control unit. Alternatively, the transport device itself can be driven by a worker manually. In this case, the target is contained in the self-shielding body, so the safety of radiation exposure can be further improved.

[0103] Can be set as Fig.11 The target irradiation system 3 shown in (a) is Fig.11In the example shown in (a), the target irradiation device 20 and the dissolving device 21 can be arranged in the irradiation room 153 which is different from the cyclotron room 152 of the building 150. At this time, the charged particle beam emitted from the cyclotron 2 is transported from the cyclotron room 152 to the target irradiation device 20 of the irradiation room 153 via the transport line 155. At this time, the target irradiation device 20 and the dissolving device 21 are supported by the floor 151 of the irradiation room 153 through the support part 156.

[0104] And, it can be set as Fig.11 (b) shows the target irradiation system 3. Fig.11 In the example (b) of FIG. 1 , the cyclotron 2, the target irradiation device 20, and the dissolution device 21 are arranged in the same cyclotron chamber 152. Figure 1 The structure shown is different, and the shielding protection body 4 can be omitted.

[0105] In addition, in the above-mentioned embodiment, a cyclotron is cited as an example of a particle accelerator, but the present invention is not limited to a cyclotron. For example, a linear accelerator may be adopted as a particle accelerator.

[0106] Can be used Fig.12 The target irradiation system 200 is shown. The target irradiation system 200 includes a fixing unit 211 of a target irradiation device 210 , a fixing unit 221 of a dissolution device 220 , a support device 230 , a target exchanger 240 , and a control unit 260 .

[0107] In order to explain the target irradiation system 200, an XYZ coordinate system is set. The X-axis direction is parallel to the horizontal direction. Fig.12 The Y-axis direction is a direction perpendicular to the X-axis direction and parallel to the horizontal direction. Fig.12 The left side of the paper in the middle is set as the positive side in the Y-axis direction. The up-down direction is set as the Z-axis direction. The upper side is set as the positive side in the Z-axis direction.

[0108] like Fig.13 As shown, the fixed unit 211 of the target irradiation device 210 is provided with an internal space 213 for the charged particle beam B to pass through at a position corresponding to the irradiation axis BL of the charged particle beam B. The internal space 213 is formed in a manner extending along the irradiation axis BL with the irradiation axis BL as a center line. In the present embodiment, the irradiation axis BL of the charged particle beam B extends parallel to the Y-axis direction. And the charged particle beam B irradiates 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.

[0109] The fixing unit 211 includes an irradiation port 212 for emitting the charged particle beam B. The irradiation port 212 has a surface extending parallel to the XZ plane as an opposing surface to the sealing surface 230a of the support device 230. The irradiation port 212 has an opening portion where the internal space 213 opens. The charged particle beam B is emitted from the opening portion.

[0110] The fixed unit 221 of the dissolution device 220 is arranged at a position separated from the fixed unit 211 of the target irradiation device 210 to the positive side in the X-axis direction. The fixed unit 221 has a plurality of dissolution ports 222A and 222B for supplying and recovering the dissolution liquid SL. The dissolution ports 222A and 222B can recover radioactive isotopes of different nuclides. Therefore, the dissolution ports 222A and 222B can supply and recover different dissolution liquids SL. However, the dissolution ports 222A and 222B can recover radioactive isotopes of the same nuclide. The dissolution ports 222A and 222B are arranged adjacent to each other in the X-axis direction. In addition, the dissolution ports 222A and 222B have surfaces extending parallel to the XZ plane as opposing surfaces opposing the sealing surface 230a of the support device 230. The center lines SCL and SCL of the opposing surfaces of the dissolution ports 222A and 222B extend parallel to the Y-axis direction in a state separated from each other in the X-axis direction. Furthermore, the center lines SCL and SCL of the dissolution ports 222A and 222B are set at the same height as the irradiation axis BL. In addition, the dissolution ports 222A and 222B can be detached from the dissolution device 220. That is, the dissolution ports 222A and 222B can be detachably mounted on the mounting table 223. Thus, the dissolution ports 222 can be replaced according to the nuclide of the radioisotope.

[0111] refer to Fig.16 and Fig.17 , the structure of the dissolution port 222A will be described in detail. In addition, the dissolution port 222B has the same structure as the dissolution port 222A, so the description is omitted. The dissolution port 222A has an opposing surface 222a for the sealing surface 230a of the support device 230 to be pressed. In addition, the dissolution port 222A has a flow path 224 and an adsorption structure 226.

[0112] The flow path 224 allows the dissolved liquid SL to circulate. The flow path 224 is formed inside the dissolution port 222A component and opens at the opposing surface 222a. The flow path 224 allows the dissolved liquid SL to flow out from the opening and sucks the dissolved liquid SL from the opening. In addition, a flow path forming component 227 protrudes from the position of the center line SCL of the opposing surface 222a and protrudes toward the negative side in the Y-axis direction. The flow path forming component 227 is a component that forms a flow path for the dissolved liquid SL in the internal space 233 by being inserted into the internal space 233 of the support device 230. The flow path 224 opens at adjacent positions in the circumferential direction of the flow path forming component 227. In addition, the dissolution port 222A has two flow paths 224, but the number is not particularly limited.

[0113] The adsorption structure 226 is a mechanism for attracting the sealing surface 230a in contact with the opposing surface 222a. The adsorption structure 226 has a circular groove 226a centered on the center line SCL. In addition, the adsorption structure 226 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.

[0114] like Fig.12 and Fig.13 As shown, the support device 230 is a device for supporting the solid target 10. The support device 230 is connected to the irradiation port 212 and is connected to the dissolution ports 222A and 222B. Therefore, the support device 230 functions as a movable unit of the target irradiation device 210. In addition, the support device 230 functions as a movable unit of the dissolution device 220. In addition, in the present embodiment, as described later, the target exchanger 240 can be equipped with a plurality of support devices 230. Therefore, the target irradiation system 200 can be equipped with a plurality of support devices 230 according to the purpose. In the present embodiment, the target irradiation system 200 is configured to have two support devices 230A and 230B.

[0115] refer to Fig.15 , the structure of the support device 230 is described in detail. Fig.15 As shown, the support device 230 is a component having a substantially cylindrical shape. The center line CL of the support device 230 extends parallel to the Y-axis direction. The support device 230 includes a first component 231 and a second component 232. The support device 230 is divided into the first component 231 and the second component 232 at a midway position in the length direction, i.e., the Y-axis direction. The first component 231 is arranged on the positive side in the Y-axis direction, i.e., the upstream side in the irradiation direction of the charged particle beam B. The second component 232 is arranged on the negative side in the Y-axis direction, i.e., the downstream side in the irradiation direction of the charged particle beam B.

[0116] The support device 230 supports the solid target 10 by sandwiching the solid target 10 between the first component 231 and the second component 232. The support device 230 supports the solid target 10 and tilts it relative to the center line CL. The tilting direction of the solid target 10 is not particularly limited. Here, the solid target 10 tilts toward the upper side (positive side of the Z-axis direction) as it moves from the positive side of the Y-axis direction toward the negative side. The first component 231 has a support surface 231a at the end of the negative side in the Y-axis direction. The second component 232 has a support surface 232a at the end of the positive side in the Y-axis direction. The support surface 231a of the first component 231 and the support surface 232a of the second component 232 are opposed to each other in a state parallel to each other. And, the support surfaces 231a, 232a are tilted in the same manner as the tilting direction of the solid target 10 described above. On the support surfaces 231a, 232a, a sealing portion having an O-ring is provided near the end of the outer peripheral side of the solid target 10.

[0117] The first component 231 has the above-mentioned sealing surface 230a at the end on the positive side of the Y-axis direction. Therefore, the first component 231 functions as a component connected to the irradiation port 212 and connected to the dissolution ports 222A and 222B. A sealing portion having an O-ring is provided on the sealing surface 230a. The first component 231 has an internal space 233 extending parallel to the Y-axis direction at the position of the center line CL. The internal space 233 extends in a manner extending from the sealing surface 230a to the supporting surface 231a. As a result, the solid target 10 is exposed to the internal space 233. The internal space 233 functions as a conveying path of the target irradiation device 210 that guides the charged particle beam B to the solid target 10. In addition, the internal space 233 functions as a dissolution tank of the dissolution device 220 that circulates the dissolving liquid SL. The first member 231 is a member that allows the charged particle beam B to pass therethrough and allows the dissolving liquid SL to flow therethrough, and therefore, as the material of the first member 231 , a material having chemical resistance, radiation resistance, and heat resistance, such as Nb or ceramics, is preferably used.

[0118] When the support device 230 is connected to the irradiation port 212, the sealing surface 230a of the first component 231 is pressed against the irradiation port 212. And the internal space 233 is in communication with the internal space 213. The support device 230 is arranged 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.

[0119] The second component 232 functions as a cooling structure for cooling the solid target 10. The second component 232 has a groove 234 at the position of the support surface 232a. The back surface 10b of the solid target 10 is exposed in the internal space of the groove 234. Therefore, the cooling medium W supplied to the groove 234 contacts the solid target 10. The second component 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. In addition, the second component 232 is a component that exposes the solid target 10, so it is preferable to use a rust-proof material such as SUS as the material of the second component 232.

[0120] Then, if Fig.16 As shown, when the support device 230 is connected to the dissolution port 222A, the sealing surface 230a of the first component 231 is pressed against the opposing surface 222a of the dissolution port 222A. The support device 230 is configured so that the center line CL coincides with the center line SCL of the dissolution port 222A. A portion of the sealing surface 230a is opposite to the groove portion 226a of the adsorption structure 226. Thus, the sealing surface 230a is adsorbed on the vacuumed groove portion 226a. In addition, the flow path forming component 227 is inserted into the internal space 233. Thus, a flow path of the dissolving liquid SL is formed in the internal space 233. The internal space 233 is in a state of being connected to the opening of the flow path 224. The dissolving liquid SL supplied from the flow path 224 contacts the surface 10a of the solid target 10. The dissolving liquid SL in which the radioactive isotope is dissolved is recovered from the flow path 224.

[0121] Next, the target exchanger 240 will be described. Fig.12 and Fig.13 As shown, the target exchanger 240 functions as a conveying device for conveying the solid target 10. The target exchanger 240 supports the solid target 10 via the supporting device 230. The target exchanger 240 includes a holder 241 on which a plurality of supporting devices 230 can be mounted. Therefore, the target exchanger 240 can support a plurality of solid targets 10. Furthermore, the holder 241 can slide in the X-axis direction in a state where the plurality of supporting devices 230 are mounted. Therefore, the holder 241 can convey the solid target 10 in the X-axis direction together with the plurality of supporting devices 230.

[0122] refer to Fig.14 , an example of the specific structure of the target exchanger 240 is described. Fig.14 As shown, 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 .

[0123] The base plate 242 is a member that serves as a base plate for mounting the first sliding plate 243 and the second sliding plate 244. A guide rail 242a extending in the Y-axis direction is provided on the upper surface of the base plate 242 (see FIG. Fig.12 The base plate 242 is connected to a fixing plate 249 in an orthogonal manner, and the fixing plate 249 is used to install and fix the target exchanger 240 to the cyclotron.

[0124] The first sliding plate 243 is a plate-shaped member having a rectangular shape when viewed from above. A guide rail 251 extending along the X-axis direction is provided at the edge portion of the positive side of the first sliding plate 243 in the Y-axis direction. The first cylinder 246 is installed on the side surface of the negative side of the first sliding plate 243 in the Y-axis direction. The first cylinder 246 moves the drive shaft forward and backward in the Y-axis direction, thereby reciprocating the holder 241 and the first sliding plate 243 in the Y-axis direction. The second cylinder 247 is mounted on the upper surface of the first sliding plate 243. The drive shaft of the second cylinder 247 is capable of moving forward and backward in the X-axis direction.

[0125] The third cylinder 248 is mounted on the upper surface of the first sliding plate 243. The driving shaft of the third cylinder 248 is capable of moving forward and backward in the Y-axis direction. The driving shaft of the second cylinder 247 is connected to the third cylinder 248. Therefore, the second cylinder 247 moves the driving shaft forward and backward in the X-axis direction, thereby reciprocating the third cylinder 248 in the X-axis direction together with the retaining frame 241 engaged with the driving shaft (details will be described later).

[0126] A mounting plate 252 extending in the Y-axis direction is mounted on the upper surface of the third cylinder 248. A striking member 253 is mounted on the positive end of the mounting plate 252 in the Y-axis direction. The striking member 253 abuts against a micro switch 259 provided on the second slide plate 244 described later, thereby detecting the position of the second slide plate 244 in the X-axis direction.

[0127] The second sliding plate 244 has a rectangular base 256 and a retaining frame 241 erected on the base 256. On the lower surface of the base 256, a bushing 255 with a U-shaped cross-section extending in the X-axis direction is installed. The retaining frame 241 is rectangular when viewed from the front. The retaining frame 241 has four retaining holes 257 for retaining the supporting device 230, and these retaining holes 257 respectively embed and retain a roughly cylindrical supporting device 230. The four retaining holes 257 are arranged side by side along the X-axis direction. Thus, the retaining frame 241 can retain up to four supporting devices 230. In the present embodiment, the retaining frame 241 retains two supporting devices 230A and 230B, but two more supporting devices 230 can be retained by adding.

[0128] Four micro switches 259 are mounted on the front surface of the base 256 of the second slide plate 244 at the same interval as the interval of the holding holes 257. The striking member 253 abuts against the micro switches 259 to detect the position of the second slide plate 244 in the X-axis direction. In addition, engaging holes 261 are provided below the micro switches 259. The engaging holes 261 are configured such that the diameter thereof is substantially the same as the diameter of the drive shaft of the third cylinder 248, and the drive shaft can be engaged in the engaging holes 261. Thus, the holder 241 is driven by the second cylinder 247 to reciprocate in the X-axis direction.

[0129] 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 opposite to the irradiation port 212 or the dissolution port 222A, 222B. At this time, the target exchanger 240 has a mechanism for pressing the support device 230 against the irradiation port 212 or the dissolution port 222A, 222B. Specifically, as Fig.12 and Fig.13 As shown, the target exchanger 240 has push-out mechanisms 270A and 270B. The push-out mechanisms 270A and 270B include: a support member 271 connected to the first sliding plate 243; a cylinder 272 that moves the drive shaft forward and backward in the Y-axis direction; and a push-out member 273 that pushes out the support device 230. The push-out member 273 is disposed on the drive shaft of the cylinder 272. Thus, the push-out member 273 is moved toward the positive side in the Y-axis direction by the cylinder 272, and the support device 230 is pressed toward the dissolution device 220 side. Fig.13 As shown, the ejection mechanism 270A is disposed at a position opposite to the support device 230A. The ejection mechanism 270B is disposed at a position opposite to the support device 230B. For example, when the support device 230A is disposed at a position opposite to the dissolution port 222B by the retaining frame 241 (refer to Fig. 20 ), the ejection mechanism 270A presses the support device 230A onto the dissolution port 222B.

[0130] The control unit 260 controls the operation of the target exchanger 240 by sending control signals to the driving units (cylinders) of the target exchanger 240. Fig.13 and Figure 18 to Figure 23 , an example of the control content by the control unit 260 will be described. 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 can be changed appropriately.

[0131] Fig.13 and Figure 18 to Figure 23 An example of the operation when the radioactive isotope of one nuclide is recovered using two solid targets 10 is shown. Fig.13As shown in FIG. 2 , the two support devices 230A and 230B are held by the holder 241. When viewed from the positive side in the X-axis direction, the support device 230A is held in the first holding hole 257. When viewed from the positive side in the X-axis direction, the support device 230B is held in the second holding hole 257. The control unit 260 controls the second cylinder 247 (refer to FIG. 247 ) of the target exchanger 240. Fig.14 ) and the holder 241 is arranged at a position opposite to the fixing unit 211. At this time, the holding hole 257 on the most positive side of the holder 241 in the X-axis direction, that is, the support device 230A is arranged at a position opposite to the irradiation port 212. This position is called the "initial position". In addition, in the following description, this control content is expressed as "the control unit 260 arranges the support device 230A at a position opposite to the irradiation port 212". The same expression is also used for the control content with the same purpose as this control content.

[0132] Then, if Fig.18 As shown, the control unit 260 controls the first cylinder 246 of the target exchanger 240 so that the first sliding plate 243 (reference Fig.12 ) moves toward the positive side in the Y-axis direction, thereby pressing the support device 230A onto 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 does not particularly press on other components. In addition, in the following description, the control content is expressed as "the control unit 260 presses the support device 230A onto the irradiation port 212". The same expression is also used for the control content with the same purpose as the control content. The control unit 260 controls the target irradiation device 210 to irradiate the charged particle beam B onto the solid target of the support device 230A. If the irradiation is completed, the control unit 260 releases the support device 230A from pressing the irradiation port 212.

[0133] Then, if Fig.19 As shown in FIG. 2 , the control unit 260 arranges the support device 230A at a position opposite to the dissolution port 222B. Fig. 20 As shown, the control unit 260 controls the first cylinder 246 of the target exchanger 240 so that the first sliding plate 243 (reference Fig.12) moves toward the positive side in the Y-axis direction, thereby arranging the support device 230A near the dissolution port 222B. In addition, the control unit 260 presses the support device 230A onto the dissolution port 222B by extending the cylinder 272 of the ejection mechanism 270A. At this time, the support device 230B also moves toward the positive side in the Y-axis direction, but the support device 230B does not particularly press on other components. In addition, in the following description, the control content is expressed as "the control unit 260 presses the support device 230A onto the dissolution port 222B". The same expression is also used for the control content with the same purpose as the control content. The control unit 260 controls the dissolution device 220 to supply the dissolving liquid SL to the support device 230A, and recovers the dissolving liquid SL in which the radioactive isotopes of the solid target 10 are dissolved. If the recovery is completed, the control unit 260 releases the support device 230A from pressing the dissolution port 222B. Then, the control unit 260 returns the positions of the support devices 230A and 230B to the initial positions.

[0134] Then, if Fig.21 As shown, the control unit 260 arranges the support device 230B at a position opposite to 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 pressing of the support device 230B against the irradiation port 212.

[0135] Then, if Fig. 22 As shown, the control unit 260 arranges the support device 230B at a position opposite to the dissolution port 222B, and presses the support device 230B onto the dissolution port 222B. The control unit 260 controls the dissolution device 220 to supply the dissolution liquid SL to the support device 230B, and recovers the dissolution liquid SL in which the radioactive isotopes of the solid target 10 are dissolved. When the recovery is completed, the control unit 260 releases the pressing of the support device 230B on the dissolution port 222B. Then, the control unit 260 restores the positions of the support devices 230A and 230B to the initial positions. As described above, the recovery of the radioactive isotopes using the two solid targets 10 is completed.

[0136] Next, an example of the operation when the radioactive isotopes of two nuclides are recovered using two solid targets 10 will be described. In addition, the operation common to the above operation will be described using the common drawings.

[0137] The control unit 260 executes Fig.18 The operation shown irradiates the solid target 10 of the support device 230A with the charged particle beam B. Fig.23As shown, the control unit 260 arranges the support device 230A at a position opposite to the dissolution port 222A, and presses the support device 230A against the dissolution port 222A. The control unit 260 controls the dissolution device 220 to supply the dissolution liquid SL to the support device 230A, and recovers the dissolution liquid SL in which the radioactive isotopes of the solid target 10 are dissolved. When the recovery is completed, the control unit 260 releases the pressing of the support device 230A on the dissolution port 222A. Then, the control unit 260 restores the positions of the support devices 230A and 230B to the initial positions.

[0138] Next, the control unit 260 executes Fig.21 The operation shown irradiates the solid target 10 of the support device 230B with the charged particle beam B. Next, by executing Fig. 22 The action shown in FIG. 2 recovers the radioactive isotope of the solid target 10 of the support device 230B. At this time, the dissolution port 222B uses a dissolving liquid SL different from the dissolving liquid used in the dissolution port 222A. Thus, the radioactive isotope of the solid target 10 of the support device 230B is recovered by the dissolving liquid SL different from the dissolving liquid for the support device 230A. Then, the control unit 260 returns the positions of the support devices 230A and 230B to the initial positions. As described above, the recovery of the radioactive isotope using the two solid targets 10 is completed.

[0139] In addition, it is also possible to use one solid target 10 to recover the radioactive isotope of one nuclide. Figures 18 to 20 The support device 230B is omitted and only the support device 230A is used. Figures 18 to 20 Action shown.

[0140] As described above, the target irradiation system 200 further includes a target exchanger 240 for conveying the solid target 10, and the target exchanger 240 can support a plurality of solid targets 10. In this case, the target exchanger 240 can convey a plurality of solid targets 10 to the irradiation position and the dissolution position without disassembling the solid targets 10 on the way. Thus, the influence of radiation exposure caused by the disassembly work can be reduced.

[0141] For example, in recycling Fig.18 , 23 After the radioactive isotope of the solid target 10 of the support device 230A shown in FIG. 1 is removed, the solid target 10 is replaced without any special work (disassembly work) or the like. Fig.21 , 22In this way, in the target irradiation system 200, once the solid targets 10 are set for a plurality of the supporting devices 230, the target irradiation system 200 can automatically perform multiple switching, irradiation, dissolution and recovery processes of the solid targets 10. As a result, the radiation exposure associated with the replacement work of the solid targets 10 can be greatly reduced.

[0142] The target irradiation system 200 further includes a support device 230 for supporting the solid target 10. The target irradiation device 210 includes an irradiation port 212 for emitting a charged particle beam B. The dissolution device 220 includes dissolution ports 222A and 222B for supplying and recovering a dissolving liquid SL. The support device 230 can be connected to the irradiation port 212 and to the dissolution ports 222A and 222B. In this case, the support device 230 can serve as both a part of the target irradiation device 210 and a part of the dissolution device 220.

[0143] The dissolution device 220 may include a plurality of dissolution ports 222A and 222B for supplying and recovering the dissolution liquid SL. In this case, the dissolution process of radioactive isotopes of a plurality of nuclides can be performed without replacing the dissolution ports 222A and 222B.

[0144] Explanation of symbols

[0145] 2-cyclotron, 3, 200-target irradiation system, 4-shielding protection body (supporting part), 10-solid target, 11-metal layer, 20, 210-target irradiation device, 21, 220-dissolving device, 22-conveying device, 50-control part, 70-accommodating part, 71-exhaust part, 100-self-shielded cyclotron system, 212-irradiation port, 222A, 222B-dissolving port, 230, 230A, 230B-supporting device (target irradiation device, dissolving device), 240-target exchanger (conveying device).

Claims

1. A target irradiation system for generating radioactive isotopes by irradiating a charged particle beam emitted from an accelerator, the target irradiation system comprising: a target irradiation device that holds a solid target at an irradiation position of the charged particle beam so as to be able to irradiate the solid target with the charged particle beam; and a dissolving device for dissolving the radioactive isotope attached to the solid target irradiated with the charged particle beam by the target irradiation device using a strong acid, The irradiated solid is targeted to slide on the dissolution device.

2. The target irradiation system according to claim 1, further comprising: a support portion supporting the target irradiation device, The dissolving device is supported by the supporting portion.

3. The target irradiation system according to claim 1 or 2, further comprising: a conveying device for conveying the solid target from the target irradiation device to the dissolution device; and Control Department, The control unit controls the transport device so as to transport the solid target held by the target irradiation device to the dissolution device after the metal layer is irradiated with the charged particle beam.

4. The target irradiation system according to any one of claims 1 to 3, further comprising: a conveying device for conveying the solid target, The transport device is capable of supporting a plurality of the solid targets.

5. The target irradiation system according to any one of claims 1 to 4, further comprising: a supporting device, supporting the solid target, The target irradiation device includes an irradiation port for emitting the charged particle beam. The dissolving device is provided with a dissolving port for supplying and recovering the dissolving liquid. The supporting device is connected to the irradiation port and to the dissolution port.

6. The target irradiation system according to any one of claims 1 to 5, wherein: The dissolving device includes a plurality of dissolving ports for supplying and recovering a dissolving liquid.

7. The target irradiation system according to any one of claims 1 to 6, wherein: The target irradiation device and the dissolution device are arranged in the same room installed in a building.

8. A method for recovering radioactive isotopes from a solid target, wherein the method recovers radioactive isotopes attached to a solid target having a metal layer, wherein: The solid target irradiated with the charged particle beam is slid and transported to the dissolution device by a transport device capable of transporting the solid target. The radioactive isotope attached to the solid target is dissolved by the dissolution device using a strong acid.

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