Superconducting magnet with iron core, accelerator equipped with superconducting magnet with iron core, and particle beam therapy device equipped with accelerator

Abstract

To provide a superconducting magnet with an iron core that can efficiently protect a refrigerator port part.SOLUTION: A superconducting magnet 11 with an iron core comprises: iron cores 12, 13; a coil part vacuum container 20 provided inside the iron cores, the coil part vacuum container having a main coil 23 built therein; and refrigerator port parts 30 provided in the iron cores, and each including a body part 31 provided exposed to the surface of the iron core and a cold head part 32 extending from the body part to the main coil through the iron core and connected with the main coil. A magnetic shield part 202 is provided between the body part and the cold head part through which the cold head part penetrates.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a superconducting magnet with an iron core, an accelerator equipped with a superconducting magnet with an iron core, and a particle beam therapy system equipped with an accelerator. [Background technology]

[0002] High-energy ion beams used in particle beam therapy, physics experiments, etc. are generated using accelerators. Known accelerators that can generate beams with a kinetic energy per nucleon of around 200 MeV include, for example, cyclotrons, synchrotrons, and synchrocyclotrons (Patent Documents 1 and 2).

[0003] Patent Document 1 discloses a circular accelerator that accelerates a charged particle beam while increasing the orbital radius by applying high frequency waves in a main magnetic field, and that emits a charged particle beam by applying high frequency waves to the charged particle beam that have a different frequency from the high frequency waves used for acceleration.

[0004] Accelerators using superconducting magnets with iron cores, such as superconducting cyclotrons and superconducting synchrocyclotrons, are provided with multiple refrigerators to cool the main coil to ultra-low temperatures (Patent Document 2). In Patent Document 2, cryocoolers are provided in the radial direction.

[0005] Patent Document 3 discloses a superconducting magnet device with a refrigerator, which includes a vacuum vessel containing a superconducting coil and a magnetic shield that prevents the magnetic field generated by the superconducting coil from leaking to the outside. In Patent Document 3, the members that make up the vacuum vessel and the magnetic shield are integrally formed (see paragraphs 0033 and 0043 of Patent Document 3). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-133745 [Patent Document 2] Patent No. 5481070 [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-281469 Summary of the Invention [Problem to be solved by the invention]

[0007] However, due to constraints on accelerator installation, it is possible to install the refrigerator directly above or below the main coil. In this case, a through-hole is formed from the top or bottom surface of the core toward the main coil inside the core, and the refrigerator port is inserted into the through-hole so that it comes into contact with the main coil.

[0008] The main body of the refrigerator port houses a directional control valve, an electric motor, etc., and so it is necessary to protect these electrical devices with a magnetic shield to prevent leakage magnetic flux from the superconducting coil from adversely affecting them. It is possible to shield the entire surface of the iron core by covering it with a magnetic material, but this would increase costs.

[0009] On the other hand, when performing maintenance on an iron-cored superconducting magnet, the upper and lower iron cores must be separated to inspect or replace the internal components or adjust the magnetic field. However, if a refrigerator port is provided on the top or bottom of the iron core, handling the hoses and power cables for circulating the coolant connected to the refrigerator port becomes problematic. Removing these hoses and cables from the main electromagnet allows for disassembly and maintenance of the iron-cored superconducting magnet. However, removing the hoses and cables from the refrigerator port makes it impossible to maintain the main coil at a predetermined temperature, causing the main coil temperature to rise, resulting in a longer restart time for the accelerator after maintenance work. When an accelerator with an iron-cored superconducting magnet is used in a particle beam therapy system, the longer the restart time after maintenance work, the lower the treatment efficiency, which negatively impacts hospital management.

[0010] The present disclosure provides a superconducting magnet with an iron core that can efficiently protect a refrigerator port portion. [Means for solving the problem]

[0011] In order to solve the above problems, the iron-cored superconducting magnet according to the present invention comprises an iron core, a coil section vacuum vessel provided within the iron core, the coil section vacuum vessel containing a main coil, a refrigerator port provided in the iron core, a main body section provided so as to be exposed on the surface of the iron core, and a cold head section extending from the main body section through the iron core to the main coil and connected to the main coil, and a magnetic shield section provided between the main body section and the cold head section, the cold head section being provided so as to penetrate the magnetic shield section. [Effects of the Invention]

[0012] According to the present invention, the main body of the refrigerator port can be protected by the magnetic shield. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a top view showing one form of accelerator. [Figure 2] Side view of the accelerator. [Figure 3] Axial cross section of the accelerator. [Figure 4] FIG. 5 is an enlarged cross-sectional view of a part of FIG. 4. [Figure 5] FIG. 10 is an explanatory diagram schematically showing a state in which the upper core portion is displaced upward. [Figure 6] FIG. 10 is an explanatory diagram schematically showing a state in which the upper iron core portion and the coil portion vacuum vessel are displaced upward. [Figure 7] Overall configuration diagram of a particle beam therapy device that uses an accelerator. DETAILED DESCRIPTION OF THE INVENTION

[0014] Below, a superconducting magnet with an iron core and an accelerator equipped with a superconducting magnet with an iron core will be described with reference to the drawings. Furthermore, a particle beam therapy device equipped with an accelerator will also be described. In this embodiment, a refrigerator port is provided at least above or below the iron core, and is located as close as possible to the main coil. Furthermore, in this embodiment, a magnetic shield is provided between the main body of the refrigerator port and the cold head of the refrigerator port, thereby effectively protecting electrical equipment (e.g., an electric motor) built into the main body from leakage magnetic flux.

[0015] Furthermore, in this embodiment, the refrigerator port is protected by a magnetic shield with the minimum necessary area, so that part of the iron core can be separated and displaced in the axial direction while the refrigerator port and the compressor body are connected by a cable.

[0016] As a result, in this embodiment, the core can be divided in the axial direction and displaced upward while the refrigerator port is operating, while protecting the refrigerator port from leakage magnetic flux, allowing maintenance work on the iron-cored superconducting magnet to be performed. After the maintenance work on the iron-cored superconducting magnet is completed, the iron core that was displaced upward can be returned to its original position, allowing the accelerator to be operated. In this embodiment, maintenance work on the iron-cored superconducting magnet can be performed while the main coil is still cooled by the refrigerator port, allowing the accelerator to be quickly restarted.

[0017] Therefore, in the particle beam therapy device equipped with the accelerator described in this embodiment, the treatment time can be extended while efficiently maintaining the superconducting magnet with an iron core, and a large number of patients can be treated.

[0018] This embodiment discloses an apparatus having the following configuration.

[0019] (Representation 1) A superconducting magnet with an iron core, comprising: an iron core; a coil vacuum vessel provided within the iron core, the coil vacuum vessel incorporating a main coil; a refrigerator port provided in the iron core, the main body provided exposed on the surface of the iron core; and a cold head extending from the main body through the iron core to the main coil and connected to the main coil, wherein a magnetic shield is provided in the portion where the main body is installed.

[0020] (Representation 2) The superconducting magnet with an iron core according to Representation 1, wherein the magnetic shield portion is provided in a region where the main body portion contacts the iron core.

[0021] (Representation 3) The superconducting magnet with an iron core according to Representation 2, wherein the magnetic shield section is provided as a part of the coil section vacuum vessel.

[0022] (Representation 4) The superconducting magnet with an iron core according to Representation 3, further comprising a case made of a magnetic material that covers the main body.

[0023] (Representation 5) A superconducting magnet with an iron core, wherein the iron core comprises an upper core portion located axially above the iron core and a lower core portion located axially below the iron core, the coil portion vacuum vessel is located between the upper core portion and the lower core portion and is provided within the iron core, the refrigerator port portion is provided in at least one of the upper core portion or the lower core portion, the main body portion is connected to a compressor main body via a cable, and the iron core is provided so that a refrigerator port installation area where the refrigerator port portion is provided and other areas are displaceable axially relative to each other.

[0024] (Representation 6) A superconducting magnet with an iron core according to Representation 5, wherein the refrigerator port installation area has a plurality of first dividing lines extending from both sides of the refrigerator port portion to the outer edge of the iron core, and the plurality of first dividing lines are formed up to a second dividing line provided in the axial direction of the iron core.

[0025] (Representation 7) A superconducting magnet with an iron core according to Representation 6, in which, when the refrigerator port installation area and the other area are displaced relative to each other in the axial direction, a passage for the cable to pass through is formed on the side of the iron core in a direction parallel to the axial direction.

[0026] (Representation 8) The superconducting magnet with an iron core according to Representation 7, wherein the refrigerator port is provided on the upper iron part and the lower iron part.

[0027] (Representation 9) The superconducting magnet with an iron core according to Representation 8, wherein the second parting line is set at a position that displaces the upper core portion axially upward.

[0028] (Representation 10) A superconducting magnet with an iron core according to Representation 8, wherein the second dividing line is set at a position that displaces the upper iron core portion and the coil portion vacuum vessel axially upward.

[0029] (Representation 11) A superconducting magnet with an iron core according to Representation 8, wherein the second dividing lines include an upper second dividing line set at a position that displaces the upper core section axially upward, and a lower second dividing line set at a position that displaces the upper core section and the coil section vacuum vessel axially upward.

[0030] (Representation 12) A superconducting magnet with an iron core according to Representation 9, further comprising a lifting member, the cylinder body of the lifting member being attached to the lower iron part, and a rod provided in an extendable manner on the cylinder body being attached to the upper iron part.

[0031] (Representation 13) An accelerator comprising the superconducting magnet with an iron core according to any one of Representations 1 to 12.

[0032] (Representation 14) A particle beam therapy device comprising: an irradiation device that irradiates a target with a beam accelerated by the accelerator according to Representation 13; and a control device that controls the accelerator and the irradiation device. [Example]

[0033] The first embodiment will be described with reference to Figures 1 to 7. Figure 1 is a top view of the accelerator 10. Figure 2 is a side view of the accelerator 10. Figure 3 is an axial cross-sectional view of the accelerator 10.

[0034] A total of four lifting members 40 may be provided on the outer periphery of the main electromagnet 11, spaced apart by 90 degrees, or a total of three lifting members 40 may be provided on the outer periphery of the main electromagnet 11, spaced apart by 120 degrees. Alternatively, five or more lifting members 40 may be provided on the outer periphery of the main electromagnet 11.

[0035] The accelerator 10 of this embodiment is, for example, a frequency modulation type variable energy accelerator. This accelerator 10 is a circular accelerator that has a time-constant magnetic field as a main magnetic field and accelerates ions (protons, carbon) circulating in the main magnetic field by a high-frequency electric field.

[0036] The accelerator 10 includes a radio frequency acceleration cavity 101 (see FIG. 7) that forms an accelerating electric field for accelerating ions, a rotary variable capacitor (not shown) for modulating the frequency of the accelerating electric field, an additional magnetic field generating shim (not shown) that applies a kick action from a stable region to circulating ions by the magnetic field formed by magnetic pole 121 (see FIG. 3), a disturbance electrode (not shown) that generates a disturbance electric field for extracting ions that have been kicked by the additional magnetic field generating shim from the accelerator 1, a low-level radio frequency generator (not shown) that controls the accelerating electric field, and a disturbance radio frequency controller (not shown) that controls the disturbance electric field. The accelerator 10 has a region where the circular orbits of multiple ions, each orbiting with different energies, converge and a region where they separate, and ions injected in different cycles orbit simultaneously with approximately the same energy.

[0037] The main electromagnet 11 of the accelerator 10 is provided with a plurality of refrigerator ports 30 and a plurality of lifting members 40. The refrigerator ports 30, which are an example of "refrigerator port sections," are provided in a plurality (for example, two on each side) on the upper and lower surfaces of the main electromagnet 11. As described above, a plurality of lifting members 40 are provided spaced apart on the outer periphery of the main electromagnet 11. A plurality of support legs 50 are provided on the lower surface of the main electromagnet 11. The main electromagnet 11 is supported on a floor (not shown) by each support leg 50. The refrigerator ports 30 and the lifting members 40 will be described in more detail below.

[0038] The main electromagnet 11 of the accelerator 10 includes, for example, an upper core portion 12 located on the axially upper side, a lower core portion 13 located on the axially lower side, and an intermediate portion 14 located between the upper core portion 12 and the lower core portion 13. The intermediate portion 14 is located outside a coil portion vacuum vessel 20, which will be described later. An upper axial parting line 17, which serves as an "upper second parting line," is provided between the upper core portion 12 and the intermediate portion 14. A lower axial parting line 18, which serves as a "lower second parting line," is provided between the lower core portion 13 and the intermediate portion 14.

[0039] The middle section 14 can be fixed to the top iron 12 by a connecting member (not shown). In this case, when the top iron 12 is lifted by the plurality of lifting members 40, the middle section 14 also rises together with the top iron 12. This causes an opening to appear in the main electromagnet 11 along the axial lower parting line 18, allowing workers to perform maintenance work inside the main electromagnet 11.

[0040] Maintenance work may include, for example, measuring the magnetic field inside the main electromagnet 11, adjusting magnetic field correction equipment (not shown) based on the magnetic field measurement results, and inspecting or replacing equipment (not shown) such as a high-frequency kicker.

[0041] As will be described later, a part of the upper core portion 12 and a part of the lower core portion 13 are separated as a refrigerator port installation area 111 where a refrigerator port 30 is provided. The refrigerator port installation area 111 can also be called a refrigerator port installation section 111 or a core separation section 111.

[0042] 3, main magnetic poles 121 and 131 facing each other are provided in the center of the main electromagnet 11. The main magnetic pole 121 is provided in the center of the lower surface of the upper core portion 12, and another main magnetic pole 131 is provided in the center of the upper surface of the lower core portion 13. These main magnetic poles 121 and 131 generate a main magnetic field.

[0043] The space between the main magnetic poles 121, 131 serves as a beam passage region 16 through which the ion beam circulates. A superconducting coil (main coil) 23 is provided along the inner walls of the upper core portion 12 and the lower core portion 13 so as to surround the periphery of the main magnetic poles 121, 131.

[0044] More specifically, an upper superconducting coil 23 is provided on the inner peripheral surface of the upper core portion 12 so as to surround the outside of the main pole 121. A lower superconducting coil 23 is provided on the inner peripheral surface of the lower core portion 13 so as to surround the outside of the main pole 131. Each superconducting coil 23 is attached to and supported by a coil frame 22.

[0045] The outside of the coil frame 22 is surrounded by a coil section shield plate 21. A shield plate 201 surrounding a refrigerator port 30 provided above the main electromagnet 11 is connected to the upper side of the coil section shield plate 21. A shield plate surrounding a refrigerator port 30 provided below the main electromagnet 11 is connected to the lower side of the coil section shield plate 21. The shield plate 21 prevents heat from the outside from being transferred to the superconducting coil 23 inside the shield plate 21.

[0046] A magnetic shield part 202 is provided above the shield part 201 on a flange part on which the main body part 31 of the refrigerator port 30 is installed. The magnetic shield part 202 is made of a magnetic material such as pure iron or SS400 and has a disk or rectangular plate shape with a hole 2021 (see FIG. 4) through which the cold head 32 is inserted, so as to cover the underside of the main body part 31. In other words, the cold head 32 is provided so as to penetrate the magnetic shield part 202.

[0047] As shown in the enlarged view of FIG. 4, the superconducting coil 23, the coil frame 22, and the coil shield plate 21 are provided inside the coil vacuum vessel 20. The coil vacuum vessel 20 is also called a cryostat. The coil vacuum vessel 20 maintains the vacuum and temperature inside it. The temperature inside the coil vacuum vessel 20 is maintained by the cooling capacity of each refrigerator port 30.

[0048] The inside of the main electromagnet 11 is evacuated by a vacuum pump (not shown). The main electromagnet 11 is provided with a plurality of through-holes for connecting the outside with the beam passing region 16. For example, a beam extraction through-hole (not shown) for extracting the accelerated beam and a beam monitor mounting hole (not shown) for mounting a beam monitor are provided in the intermediate portion 14 of the main electromagnet 11. In addition, the intermediate portion 14 of the main electromagnet 11 is provided with a through-hole for extracting the coil conductor of the superconducting coil 23 to the outside and a through-hole for inputting high-frequency power to the acceleration electrode (neither of which are shown).

[0049] The structure of the cryogenic refrigerator that cools the superconducting coil 23 of the main electromagnet 11 will be described with reference to Figures 1 and 3. As described above, the top iron 12 is provided with two refrigerator ports 30 spaced apart in the diametric direction. The bottom iron 13 is also provided with two refrigerator ports 30 spaced apart in the diametric direction.

[0050] The cold head 32 extending from the main body 31 of each refrigerator port 30 incorporates a displacer (not shown). The base end of the cold head 32 passes through the magnetic shield 202 and is connected to the main body 31. The tip of the cold head 32 comes into contact with the coil frame 22 and cools the superconducting coil 23 in the coil frame 22 to a predetermined temperature.

[0051] The main body 31 is provided with an electric motor for driving the displacer, a supply directional switching valve for supplying the cooling gas to the cold head 22, and a return directional switching valve for returning the cooling gas from the cold head 22 to the compressor 37 (none of which are shown). The electric motor is electrically connected to the compressor 37 via a cable 321 (see FIG. 3).

[0052] The main body 31 is provided with a supply port 33 through which cooling gas is supplied and a return port 34 through which the cooling gas is returned to the compressor 37. The supply port 33 and the compressor 37 are mechanically connected by a supply hose 35, which is an example of "cables." The return port 34 and the cooler 37 are mechanically connected by a return hose 36, which is another example of "cables." In this way, various cables 321, 35, and 36 for connecting to an external device such as the compressor 37 are connected to the refrigerator port 30 of the cryogenic refrigerator.

[0053] The main body 31 of the refrigerator port 30 is covered with a case 38 made of a magnetic material. The main body 31 is protected from the magnetic flux generated by the superconducting coil 23 by the magnetic shield part 202 located below and the case 38 located above.

[0054] The refrigerator port installation area 111 will now be described. In the refrigerator port installation area 111, the area where the refrigerator port 30 is installed in the upper core portion 12 and the lower core portion 13 is physically separated from the other cores, and can be relatively displaced in the axial direction (up and down direction).

[0055] The refrigerator port installation region 111 will be described using the upper core portion 12 shown in FIG. 1 as an example. The two refrigerator ports 30 are provided diametrically opposite each other on the upper core portion 12, and the locations where they are installed on the upper core portion 12 are circular (in plan view). First dividing lines 301 are provided from both sides of the circular installation locations toward the outer edge of the upper core portion 12. Of the circular installation locations of the refrigerator ports 30, the outer edge of a semicircular portion closer to the center of the upper core portion 12 is also separated from the other cores. That is, the installation region 111 of the refrigerator ports 30 is formed in a horizontal U-shape in plan view, and is separated from the other cores other than the installation region 111. The refrigerator port installation region 111 of the upper core portion 12 is separated from the other upper core portion 12 up to the upper dividing line 17.

[0056] The magnetic shield part 202 is present in the refrigerator port installation area 111 together with the refrigerator port 30 .

[0057] Although not shown, the lower core portion 13 also has two refrigerator ports 30 that are diametrically opposed to each other. The area where each refrigerator port 30 is installed on the lower core portion 13 is circular (in plan view). First dividing lines (not shown) are provided from both sides of the circular installation area toward the outer edge of the lower core portion 13. The outer edge of the semicircular portion of the circular installation area of ​​the refrigerator port 30 that is closer to the center of the lower core portion 13 is also separated from the other cores. That is, the installation area 111 of the refrigerator port 30 is formed in a horizontal U-shape in plan view and is separated from the other cores other than the installation area 111. The area sandwiched between the first dividing lines 301 is the area where cables 321, 35, and 36 are pulled out. The cables 321 and hoses 35 and 36 are pulled out from the area sandwiched between the first dividing lines 301 toward the outer periphery along the diameter of the main electromagnet 11. Therefore, even if the refrigerator port installation area 111 and the other iron cores are displaced in the axial direction, the cables 321, 35, 36 do not need to be removed from the refrigerator port 30.

[0058] The refrigerator port installation area 111 of the lower core section 13 is separated from the other lower core sections 13 up to the lower dividing line 18. The configuration of each refrigerator port installation area 111 of the lower core section 13 is similar to the configuration of each refrigerator port installation area 111 of the upper core section 12 shown in Fig. 1. Even when the refrigerator port installation area 111 and the other cores are displaced in the axial direction, there is no need to detach cables from the refrigerator ports 30.

[0059] The lifting members 40 will now be described. A plurality of lifting members 40 are provided around the main electromagnet 11, and the lower sides of their main bodies are attached to the outer circumferential surface of the lower core portion 13. The lifting members 40 may be electrically operated, hydraulically operated, or pneumatically operated. The tips of the rods 41 of the lifting members 40 are attached to the outer circumferential surface of the upper core portion 12. By extending the rods 41, the lifting members 40 can displace only the upper core portion 12, or the upper core portion 12 and the intermediate portion 14, axially upward of the main electromagnet 11. By retracting the rods 41, the lifting members 40 can place the upper core portion 12 on the intermediate portion 14, or place the upper core portion 12 and the intermediate portion 14 on the lower core portion 13. The lifting members 40 operate in accordance with control signals from a control device (not shown). The above-mentioned cryogenic refrigerator (refrigerator port 30, compressor 37) also operates in accordance with a control signal from a control device (not shown).

[0060] FIG. 6 schematically illustrates a state in which only the upper core section 12 has been displaced upward. When the connection between the upper core section 12 and the intermediate section 14 is released and the rods 41 of each lifting member 40 are extended, the upper core section 12 moves upward away from the intermediate section 14. Because the upper core section 12 and the installation area 111 where the upper refrigerator ports 30 are provided are separated, the refrigerator port installation area 111 does not follow the upward displacement of the upper core section 12 but maintains its current position and posture. Because the cables (electrical cables, cooling gas hoses) connected to the refrigerator ports 30 do not displace either, there is no need to remove these cables from the refrigerator ports 30. In other words, the shape (in plan view) of the refrigerator port installation area 111 is set so that there is no need to remove the cables from the refrigerator ports 30. However, this description is merely an example, and the refrigerator port installation area 111 may be formed in other shapes, as shown in other embodiments described later.

[0061] When the upper core portion 12 is displaced upward, the upper side of the coil portion vacuum vessel 20 is exposed, which allows the worker to perform magnetic force measurements, set the magnetic force adjustment device, and so on.

[0062] FIG. 6 is an explanatory diagram that schematically shows a state in which the upper core portion 12 and the intermediate portion 14 (the coil portion vacuum vessel 20 held by the intermediate portion 14) are displaced upward.

[0063] The intermediate section 14 is attached to the outside of the coil vacuum vessel 20. When the rod 41 of the lifting member 40 is extended while the intermediate section 14 and the upper core section 12 are connected by a connecting member (not shown), the upper core section 12, the intermediate section 14, and the coil vacuum vessel 20 are displaced upward. This allows workers to inspect or repair the area around the coil vacuum vessel 20.

[0064] Even when the upper core section 12, the intermediate section 14, and the coil section vacuum vessel 20 are displaced upward, the refrigerator port installation area 111 maintains its position and posture, and the cables connected to the refrigerator port 30 do not interfere with the upward displacement of the upper core section 12, the intermediate section 14, and the coil section vacuum vessel 20. Therefore, the main electromagnet 11 can be partially disassembled to perform maintenance work while the refrigerator port 30 is still operating.

[0065] 7 is a diagram showing the overall configuration of a particle beam therapy system 1 that uses an accelerator 10. The particle beam therapy system 1 includes the accelerator 10, a beam transport system 2, an irradiation device 3, a treatment table 4, an overall control device 5, an irradiation control device 6, a treatment plan database 7, and a treatment planning device 8.

[0066] The RF acceleration cavity 101 forms an accelerating electric field for accelerating ions into an ion beam through a RF power input through-hole (not shown). The RF acceleration cavity 101 is equipped with, for example, an acceleration dee electrode and a rotary variable capacitor (neither of which is shown) for modulating the frequency of the accelerating electric field.

[0067] An ion source 103 for supplying hydrogen ions is installed at a position offset from the center above the main electromagnet 11. The ion source 103 supplies ions to a beam passage region 16 inside the accelerator 10 through a beam injection through-hole (not shown).

[0068] The beam transport system 2 is a mechanism that transports an ion beam (hereinafter also referred to as the beam) accelerated by the accelerator 10 to the irradiation device 3. The irradiation device 3 is a device that irradiates the beam transported by the beam transport system 2 onto a target within a patient PT fixed to a treatment table 4. An overall control device 5 controls the accelerator 10, the beam transport system 2, and the irradiation device 3. An irradiation control device 6 controls the beam irradiation onto the target. A treatment plan database 7 stores treatment plans created by a treatment planning device 8. The treatment planning device 8 creates a beam irradiation plan for the target.

[0069] In the particle beam therapy system 1, the energy and dose of the particle beam to be irradiated are determined by a treatment plan. The energy and dose of the particle beam determined by the treatment plan are input sequentially from the overall control device 5 to the irradiation control device 6. After irradiating the target with an appropriate dose, the particle beam therapy system 1 shifts to the next energy and irradiates the target with the beam again.

[0070] According to the particle beam therapy device 1 configured in this manner, since it is equipped with the accelerator 10 described above, maintenance work on the main electromagnet 11 can be performed while each refrigerator port 30 is operating, thereby extending the time for treating patients.

[0071] According to the present embodiment configured as described above, the magnetic shield part 202 is provided between the main body part 31 of the refrigerator port 30 and the cold head 32, so that the leakage magnetic flux from the superconducting coil 23 can be prevented from affecting the electrical equipment inside the main body part 31.

[0072] In this embodiment, the main body 31 is further covered with a case 38 made of a magnetic material, so that the main body 31, together with the magnetic shield 202, can be protected from leakage magnetic flux.

[0073] According to this embodiment, in the superconducting magnet 11 with an iron core, which is cooled from above and below the iron cores 12 and 13 by bringing the refrigerator port 30 close to the superconducting coil 23, the iron cores 12 and 13 are arranged so that the refrigerator port installation area 111 where the refrigerator port portion 30 is provided and other areas can be displaced relatively in the axial direction, so that maintenance work on the main electromagnet 11 can be performed while the refrigerator port 30 is operating.

[0074] In this embodiment, when the refrigerator port installation area 111 and other areas are displaced relative to each other in the axial direction, a passage for passing cables is formed on the side of the core in a direction parallel to the axial direction. Therefore, even if part of the core separates and displaces in the axial direction, it is possible to prevent the cables of each refrigerator port 30 from interfering with the core, and maintenance work on the main electromagnet 11 can be performed while each refrigerator port 30 is operating.

[0075] In this embodiment, as shown in Fig. 1, two refrigerator ports 30 are provided facing each other in the diameter direction of the main electromagnet 11, so that the superconducting coil 23 can be cooled evenly. Furthermore, in this embodiment, as shown in Fig. 3, each refrigerator port 30 penetrating the upper core portion 12 and each refrigerator port 30 penetrating the lower core portion 13 are arranged on a straight line in the axial direction. This simplifies the overall configuration.

[0076] The line connecting the two refrigerator ports 30 axially penetrating the upper core portion 12 (the line in the diameter direction of the main electromagnet 11; the same applies below) and the line connecting the two refrigerator ports 30 axially penetrating the lower core portion 13 may be set at different angles. For example, the line connecting the upper refrigerator ports 30 and the line connecting the lower refrigerator ports 30 may be configured to differ by a predetermined angle, such as 90 degrees.

[0077] In this embodiment, because the refrigerator ports 30 are placed close to the superconducting coils 23 and cooled from above and below the axial direction of the iron cores 12 and 13, the radial dimension of the main electromagnet 11 can be reduced, and the area required for installing the accelerator 10 can be reduced. For example, if the refrigerator ports are inserted from the radial direction of the main electromagnet as in Patent Document 2, the radial dimension of the accelerator increases, which increases the area required for installation and increases installation costs. In contrast, in this embodiment, the refrigerator ports 30 are attached from above and below the main electromagnet 11, so the radial dimension of the accelerator 10 can be shortened, the area required for installing the accelerator 10 can be reduced, and installation costs can be reduced.

[0078] In this embodiment, a total of four refrigerator ports 30 are arranged, two above and two below the main electromagnet 11. Therefore, by adjusting the cooling capacity setting, even if one of the refrigerator ports 30 fails, the other three refrigerator ports 30 can maintain the superconducting coil 23 at a predetermined temperature.

[0079] In this embodiment, the lower side of the main body 31 of the refrigerator port 30 is protected by the magnetic shield 202, and the iron core 111 in the area where the refrigerator port 30 is installed is separated from the other iron cores. Therefore, the main body 31 of the refrigerator port 30 can be protected from leakage magnetic flux, and the iron core can be separated into upper and lower parts while the refrigerator port 30 is operating.

[0080] In this embodiment, the cold head 32 is provided so as to penetrate the magnetic shield 202, allowing the main body 31 to be brought closer to the surface of the iron core. This allows the length from the cold head 32 to the superconducting coil 23 to be shortened, allowing the superconducting coil 23 to be cooled efficiently. In contrast, if a magnetic shield is not provided below the main body 31, the cold head 32 needs to be located away from the superconducting coil 23 to protect the electrical equipment inside the main body 31 from leakage magnetic flux of the superconducting coil 23. However, if the cold head 32 is located away from the superconducting coil 23, the superconducting coil 23 cannot be cooled efficiently.

[0081] The present invention is not limited to the above-described embodiments. Those skilled in the art can make various additions and modifications within the scope of the present invention. The above-described embodiments are not limited to the configuration examples shown in the accompanying drawings. The configurations and processing methods of the embodiments can be modified as appropriate within the scope of achieving the object of the present invention. For example, the shape of the refrigerator port installation area is not limited to that shown in the drawings.

[0082] Furthermore, the components of the present invention can be selected arbitrarily, and the invention including the selected components is also included in the present invention. Furthermore, the components described in the claims can be combined in combinations other than those explicitly stated in the claims. [Explanation of symbols]

[0083] 1: particle beam therapy device, 2: beam transport system, 3: irradiation device, 4: treatment table, 5: overall control device, 6: irradiation control device, 7: treatment plan database, 8: treatment plan device, 10: accelerator, 11, 11A, 11B: main electromagnet, 12: upper iron core section, 13: lower iron core section, 14: intermediate section, 20: coil section vacuum vessel, 23: superconducting coil, 30: refrigerator port, 31: main body section, 32: cold head, 35, 36: cooling gas hose, 38: case, 40: lifting member, 111: refrigerator port installation area, 202: magnetic shield section, 301: first dividing line, 321: power cable

Claims

1. A superconducting magnet with an iron core, Iron core and a coil section vacuum vessel provided within the iron core, the coil section vacuum vessel housing a main coil; a refrigerator port provided in the iron core, the refrigerator port including: a main body provided and exposed on a surface of the iron core; and a cold head extending from the main body through the iron core to the main coil and connected to the main coil; A magnetic shield is provided between the main body and the cold head, and the cold head penetrates the magnetic shield. Superconducting magnet with iron core.

2. The magnetic shield is provided as a part of the coil vacuum vessel.

2. The superconducting magnet with an iron core according to claim 1.

3. The main body is further provided with a case made of a magnetic material.

3. The superconducting magnet with an iron core according to claim 2.

4. the core includes an upper core portion located on the axially upper side of the core and a lower core portion located on the axially lower side of the core, the coil portion vacuum vessel is provided within the iron core and is located between the upper iron core portion and the lower iron core portion, the refrigerator port portion is provided in at least one of the upper core portion and the lower core portion, and the main body portion is connected to a compressor main body via a cable and a hose, The iron core is provided such that a refrigerator port installation area where the refrigerator port portion is provided and other areas are relatively displaceable in the axial direction.

2. The superconducting magnet with an iron core according to claim 1.

5. The refrigerator port installation region has a plurality of first division lines extending from both sides of the refrigerator port portion to an outer edge of the iron core, and the plurality of first division lines are formed to a second division line provided in the axial direction of the iron core.

5. The superconducting magnet with an iron core according to claim 4.

6. When the refrigerator port installation area and the other area are displaced relative to each other in the axial direction, a passage portion through which the cables and hoses pass is formed on a side surface of the core along a direction parallel to the axial direction.

6. The superconducting magnet with an iron core according to claim 5.

7. The refrigerator port portion is provided in the upper core portion and the lower core portion.

7. The superconducting magnet with an iron core according to claim 6.

8. The second dividing line is set at a position that displaces the upper core portion axially upward.

8. The superconducting magnet with an iron core according to claim 7.

9. The second dividing line is set at a position that displaces the upper core portion and the coil portion vacuum vessel axially upward.

8. The superconducting magnet with an iron core according to claim 7.

10. The second dividing lines include an upper second dividing line set at a position that displaces the upper core portion axially upward, and a lower second dividing line set at a position that displaces the upper core portion and the coil portion vacuum vessel axially upward.

8. The superconducting magnet with an iron core according to claim 7.

11. It also has a lifting member, The cylinder body of the lifting member is attached to the lower core portion, and a rod provided in an extendable manner on the cylinder body is attached to the upper core portion.

9. The superconducting magnet with an iron core according to claim 8.

12. An accelerator comprising the superconducting magnet with an iron core according to any one of claims 1 to 11.

13. an irradiation device that irradiates a target with a beam accelerated by the accelerator according to claim 12; a control device that controls the accelerator and the irradiation device; Equipped with Particle beam therapy equipment.

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