Superconducting magnet with iron core, accelerator including superconducting magnet with iron core, and particle beam therapy device including 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 device equipped with an accelerator. [Background technology]

[0002] High-energy ion beams used in particle beam therapy, physical experiments, etc. are generated by accelerators. Known accelerators that produce beams with kinetic energy per nucleon of about 200 MeV include, for example, cyclotrons, synchrotrons, and synchrocyclotrons (Patent Document 1 and Patent Document 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 emits a charged particle beam by applying to the charged particle beam a high frequency wave having a different frequency from the high frequency wave used for acceleration.

[0004] In accelerators using superconducting magnets with iron cores, such as superconducting cyclotrons and superconducting synchrocyclotrons, multiple refrigerators are provided 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 constituting 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] JP 2019-133745 A [Patent Document 2] Patent No. 5481070 [Patent Document 3] JP 2004-281469 A 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 to make 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 the electric motor and other electrical equipment with a magnetic shield to prevent leakage magnetic flux from the superconducting coil from adversely affecting them. It is possible to shield the iron core by covering almost the entire surface with a magnetic material, but this would increase costs.

[0009] On the other hand, when maintaining a superconducting magnet with an iron core, the upper and lower iron cores are separated to inspect or replace the equipment inside the core or adjust the magnetic field. However, if a refrigerator port is provided on the upper or lower surface of the core, the handling of the hose for circulating the coolant and the power cable connected to the refrigerator port becomes a problem. If these hoses and cables are removed from the main electromagnet, the superconducting magnet with an iron core can be disassembled and maintained. However, if the hoses and cables are removed from the refrigerator port, the main coil cannot be maintained at a specified temperature, the temperature of the main coil rises, and it takes time to restart the accelerator after maintenance work. When an accelerator having a superconducting magnet with an iron core is used in a particle beam therapy device, the longer the restart time after maintenance work, the lower the treatment efficiency, which has a negative impact on 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, a superconducting magnet with an iron core according to the present invention comprises an iron core, a coil section vacuum vessel provided within the iron core, the coil section vacuum vessel incorporating a main coil, a refrigerator port portion provided in the iron core, a main body portion provided and exposed on the surface of the iron core, and a cold head portion extending from the main body portion through the iron core to the main coil and connected to the main coil, a magnetic shield portion is provided between the main body portion and the cold head portion, and the cold head portion is provided so as to penetrate the magnetic shield portion. Effect of the Invention

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

[0013] [Figure 1] FIG. 1 is a top view showing one form of accelerator. [Diagram 2] Side view of the accelerator. [Diagram 3] Axial cross-sectional view of the accelerator. [Figure 4] FIG. 5 is an enlarged cross-sectional view of a portion of FIG. [Diagram 5] FIG. 13 is an explanatory diagram illustrating a state in which the upper core portion is displaced upward. [Figure 6] FIG. 13 is an explanatory diagram showing a state in which the upper core portion and the coil portion vacuum vessel are displaced upward. [Figure 7] FIG. 1 is a diagram showing the overall configuration of a particle beam therapy device that uses an accelerator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, 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 either 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 electric 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 having the minimum necessary area, so that with the refrigerator port and the compressor body connected by a cable, part of the iron core can be separated and displaced in the axial direction.

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

[0017] Therefore, in a 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, making it possible to treat a large number of patients.

[0018] In this embodiment, an apparatus having the following configuration is disclosed.

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

[0020] (Representation 2) A superconducting magnet with an iron core according to Representation 1, wherein the magnetic shield portion is provided in an area 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 portion made of a magnetic material that covers the main body portion.

[0023] (Representation 5) A superconducting magnet with an iron core, wherein the core comprises an upper core portion located axially above the core and a lower core portion located axially below the core, the coil portion vacuum vessel is located between the upper core portion and the lower core portion and is provided within the 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 core is provided such that a refrigerator port installation area where the refrigerator port portion is provided and other areas are capable of being displaced 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 division lines extending from both sides of the refrigerator port portion to the outer edge of the iron core, and the plurality of first division lines are formed up to a second division 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 portion for the cable to pass through is formed on the side of the iron core along 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 portion is provided on the upper iron portion and the lower iron portion.

[0027] (Representation 9) A 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 parting line is set at a position that displaces the upper 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 split lines include an upper second split line set at a position that displaces the upper core portion axially upward, and a lower second split line set at a position that displaces the upper core portion and the coil portion vacuum vessel axially upward.

[0030] (Representation 12) A superconducting magnet with an iron core as described in Representation 9, further comprising a lifting member, the cylinder body of the lifting member being attached to the lower iron part, and a rod extendably and contractibly attached to the cylinder body being attached to the upper iron part.

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

[0032] (Representation 14) A particle beam therapy apparatus 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. EXAMPLES

[0033] A 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. The 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 gives a kicking action from a stable region to ions orbiting by a magnetic field formed by a magnetic pole 121 (see FIG. 3), a disturbance electrode (not shown) that generates a disturbance electric field for taking out the ions 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 an area where the circular orbits of a plurality of ions orbiting with different energies are concentrated and an area where they are dispersed, and ions injected in different cycles orbit at approximately the same energy at the same time.

[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 a "refrigerator port section", are provided in a plurality (e.g., 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 side of the main electromagnet 11. The main electromagnet 11 is supported by the support legs 50 on a floor (not shown). The refrigerator ports 30 and the lifting members 40 will be described in further 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 is provided between the upper core portion 12 and the intermediate portion 14 as an "upper second parting line". A lower axial parting line 18 is provided between the lower core portion 13 and the intermediate portion 14 as a "lower second parting line".

[0039] The middle section 14 can be fixed to the top iron section 12 by a connecting member (not shown). In this case, when the top iron section 12 is lifted by the multiple lifting members 40, the middle section 14 also rises together with the top iron section 12. This causes an opening to appear in the main electromagnet 11 along the axial lower split 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 results of the magnetic field measurement, and inspecting or replacing equipment (not shown) such as a high-frequency kicker.

[0041] As 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 in which a refrigerator port 30 is provided. The refrigerator port installation area 111 can also be called a refrigerator port installation portion 111 or a core separation portion 111.

[0042] 3, main magnetic poles 121, 131 facing each other above and below 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, 131 generate a main magnetic field.

[0043] The space between the main magnetic poles 121, 131 serves as a beam passing region 16 in 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 circumferential 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 circumferential 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 the 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 on the upper side of 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 on the lower side of 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 on the upper side of the shield part 201 at 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 having a hole 2021 (see FIG. 4) through which the cold head 32 is inserted, so as to cover the lower surface side of the main body part 31. That is, 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. 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 middle part 14 of the main electromagnet 11. In addition, 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) are provided in the middle part 14 of the main electromagnet 11.

[0049] The structure of the cryogenic refrigerator for cooling the superconducting coil 23 of the main electromagnet 11 will be described with reference to Fig. 1 and Fig. 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 control valve for supplying the cooling gas to the cold head 22, and a return directional control 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, 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 in which the refrigerator port 30 is installed of 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. In the two refrigerator ports 30 provided to face each other in the diameter direction of the upper core portion 12, the locations where the refrigerator ports 30 are installed on the upper core portion 12 are circular (in plan view). A first division line 301 is provided from both sides of the circular installation location 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 port 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 division line 17.

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

[0057] Although not shown in the figure, the lower core portion 13 is also provided with two refrigerator ports 30 facing each other in the diameter direction of the lower core portion 13. In each refrigerator port 30, the portion where the refrigerator port 30 is installed on the lower core portion 13 has a circular shape (in a plan view). First division lines (not shown) are provided from both sides of the circular installation portion toward the outer edge of the lower core portion 13. Of the circular installation portion of the refrigerator port 30, the outer edge of the semicircular portion closer to the center of the lower core portion 13 is also separated from the other cores. That is, the installation region 111 of the refrigerator port 30 is formed in a horizontal U-shape in a plan view, and is separated from the other cores other than the installation region 111. The region sandwiched by each first division line 301 is the pull-out region for the cables 321, 35, 36. The cable 321 and the hoses 35, 36 are pulled out to the outer periphery side along the diameter direction of the main electromagnet 11 within the region sandwiched by each first division line 301. Therefore, even if the refrigerator port installation area 111 and the other 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 part 13 is divided from the other lower core parts 13 up to the lower dividing line 18. The configuration of each refrigerator port installation area 111 of the lower core part 13 is similar to the configuration of each refrigerator port installation area 111 of the upper core part 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 remove the cables from the refrigerator ports 30.

[0059] The lifting member 40 will be described. A plurality of lifting members 40 are provided around the main electromagnet 11, and the lower side of the main body is attached to the outer circumferential surface of the lower core portion 13. The lifting member 40 may be of an electric type, hydraulic type, or pneumatic type. The tip of the rod 41 of the lifting member 40 is attached to the outer circumferential surface of the upper core portion 12. The lifting member 40 can displace only the upper core portion 12, or the upper core portion 12 and the intermediate portion 14, to the axially upper side of the main electromagnet 11 by extending the rod 41. The lifting member 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 by contracting the rod 41. The lifting member 40 operates according to a control signal from a control device (not shown). The above-mentioned cryogenic refrigerator (refrigerator port 30, compressor 37) also operates according to a control signal from a control device (not shown).

[0060] FIG. 6 shows a schematic diagram of a state where only the upper core portion 12 is displaced upward. When the connection between the upper core portion 12 and the intermediate portion 14 is released and the rods 41 of the lifting members 40 are extended, the upper core portion 12 moves upward away from the intermediate portion 14. Since the upper core portion 12 and the installation area 111 where the upper refrigerator port 30 is provided are separated, the refrigerator port installation area 111 does not follow the upward displacement of the upper core portion 12 and maintains its current position and posture. Since the cables (electrical cables, cooling gas hoses) connected to the refrigerator port 30 are not displaced either, there is no need to remove these cables from the refrigerator port 30. In other words, the shape (in plan view) of the refrigerator port installation area 111 is set so that it is not necessary to remove the cables from the refrigerator port 30. However, this description is merely one example, and the refrigerator port installation area 111 may be formed in another shape 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. This allows an operator to perform magnetic force measurements, settings of a magnetic force adjustment device, and the like.

[0062] FIG. 6 is an explanatory diagram that shows a schematic 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 attitude, 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 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 radio frequency acceleration cavity 101 forms an accelerating electric field for accelerating ions into an ion beam through a radio frequency power input through hole (not shown). The radio frequency acceleration cavity 101 is equipped with, for example, a dee electrode for acceleration and a rotary variable capacitor for modulating the frequency of the accelerating electric field (both not shown).

[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 passing 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 to a target inside 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 to 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 device 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. When the particle beam therapy device 1 irradiates the target with an appropriate dose, it moves to the next energy and irradiates the beam to the target 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, and the time for treating the patient can be extended.

[0071] According to this embodiment configured as described above, a magnetic shield portion 202 is provided between the main body portion 31 of the refrigerator port 30 and the cold head 32, so that leakage magnetic flux from the superconducting coil 23 can be prevented from affecting the electrical equipment in the main body portion 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 portion 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, 13 by bringing the refrigerator port 30 close to the superconducting coil 23, the iron cores 12, 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 relatively in the axial direction, a passage for the cables to pass through 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, etc., 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 evenly cooled. 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 makes it possible to simplify the overall configuration.

[0076] Note that a line connecting two refrigerator ports 30 axially penetrating the upper core portion 12 (a line in the diameter direction of the main electromagnet 11; the same applies below) and a line connecting two refrigerator ports 30 axially penetrating the lower core portion 13 may be set at a different angle. 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 port 30 is arranged to be cooled from above and below the axial direction of the cores 12 and 13 in close proximity to the superconducting coil 23, the radial dimension of the main electromagnet 11 can be reduced, and the area required for installation of the accelerator 10 can be reduced. For example, when the refrigerator port is inserted from the radial direction of the main electromagnet as in Patent Document 2, the radial dimension of the accelerator increases, so the area required for installation also increases and the installation costs increase. In contrast, in this embodiment, the refrigerator port 30 is attached from above and below the main electromagnet 11, so the radial dimension of the accelerator 10 can be shortened, the area required for installation of the accelerator 10 can be reduced, and the 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 superconducting coil 23 can be maintained at a predetermined temperature by the other three refrigerator ports 30.

[0079] In this embodiment, the lower side of the main body 31 of the refrigerator port 30 is protected by the magnetic shield part 202, and the iron core 111 in the area where the refrigerator port 30 is installed is separated from the other iron cores. Therefore, it is possible to separate the upper and lower cores while protecting the main body 31 of the refrigerator port 30 from leakage magnetic flux and keeping the refrigerator port 30 in operation.

[0080] In this embodiment, the cold head 32 is provided penetrating the magnetic shield portion 202, so that the main body portion 31 can be brought closer to the surface of the iron core. This allows the length dimension from the cold head 32 to the superconducting coil 23 to be shortened, and the superconducting coil 23 can be cooled efficiently. In contrast, if the magnetic shield portion is not provided below the main body portion 31, the cold head 32 needs to be placed away from the superconducting coil 23 to protect the electric devices in the main body portion 31 from the leakage magnetic flux of the superconducting coil 23. However, if the cold head 32 is placed 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 embodiment. A person skilled in the art can make various additions and modifications within the scope of the present invention. The above-described embodiment is not limited to the configuration example shown in the attached drawings. The configuration and processing method of the embodiment can be appropriately changed 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 the one shown in the drawings.

[0082] In addition, each component of the present invention can be selected arbitrarily, and the invention having the selected configuration is also included in the present invention. Furthermore, the configurations 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 core section, 13: lower 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 is provided to penetrate the magnetic shield. A superconducting magnet with an 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 further includes 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 an axially upper side of the core, and a lower core portion located on an axially lower side of the core, the coil portion vacuum vessel is disposed within the core and is located between the upper core portion and the lower 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 upper core portion and the lower core portion are provided with the refrigerator port portion.

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

8. The second division 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 parting 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 division lines include an upper second division line set at a position that displaces the upper core portion axially upward, and a lower second division 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. Further, a lifting member is provided, 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 for irradiating a target with a beam accelerated by the accelerator according to claim 12; A control device for controlling the accelerator and the irradiation device; Equipped Particle beam therapy equipment.

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