Accelerator

Abstract

To provide an accelerator capable of simplifying a cooling structure.SOLUTION: A coil vacuum vessel 24 encloses an acceleration space 20 in which charged particles are accelerated and the acceleration space 20 is maintained in a vacuum. The heat-generating devices are placed inside the coil vacuum vessel 24. A heat sink 61 for cooling the heat-generating devices is formed as a part of the coil vacuum vessel 24.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to accelerators. [Background technology]

[0002] In accelerators such as superconducting cyclotrons and superconducting synchrocyclotrons, there are heat-generating devices in the beam acceleration space where charged particles are accelerated and shaped into a beam. Examples of heat-generating devices include high-voltage cables of radio-frequency ion extraction devices for extracting beams. In addition, parts that generate heat when hit by a beam, such as beam scrapers for adjusting the beam size, are also heat-generating devices.

[0003] If the temperature of heat-generating devices becomes high, it may cause changes in the magnetic field distribution and deterioration of the vacuum level inside the accelerator, which may lead to deterioration of the beam quality, etc. For this reason, it is necessary to properly cool the heat-generating devices.

[0004] One possible method for cooling the heat-generating devices is to directly cool the devices by installing piping through which a cooling medium such as water flows in the vacuum region of the accelerator. However, this method has the problem that the structure for laying the piping becomes complicated because various devices and wiring are installed inside the accelerator, leading to increased costs. There is also a risk that the cooling medium will leak from the piping into the accelerator.

[0005] In response to this, Patent Document 1 describes that a heat sink provided around the shielding film may be used as a cooling unit for cooling the shielding film arranged in the vacuum region inside the accelerator. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2015-75410 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, Patent Document 1 does not disclose a specific method for installing the heat sink, making it difficult to simplify the cooling structure.

[0008] An object of the present disclosure is to provide an accelerator that allows for a simplified cooling structure. [Means for solving the problem]

[0009] An accelerator according to one aspect of the present disclosure is an accelerator that accelerates and emits charged particles, and includes a vacuum vessel that encloses an acceleration space in which the charged particles are accelerated and places the acceleration space in a vacuum state, a heat-generating device disposed within the vacuum vessel, and a cooling structure for cooling the heat-generating device, the cooling structure being formed as part of the vacuum vessel. Effect of the Invention

[0010] According to the present invention, it is possible to simplify the cooling structure. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a front view of an accelerator according to one embodiment of the present disclosure. [Diagram 2] FIG. 2 is a top view of an accelerator according to one embodiment of the present disclosure. [Diagram 3] FIG. 1 is a longitudinal cross-sectional view of an accelerator according to one embodiment of the present disclosure. [Figure 4] 1 is a diagram showing a configuration on a core division surface of an accelerator according to an embodiment of the present disclosure as viewed from above. [Diagram 5] FIG. 2 is a diagram for explaining an example of a heat generating device and a cooling method thereof; [Figure 6] 11A and 11B are diagrams for explaining another example of a heat generating device and a cooling method thereof. [Figure 7] FIG. 2 is a diagram illustrating an example of a heat sink. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0013] FIG. 1 is a front view of an accelerator according to an embodiment of the present disclosure, FIG. 2 is a top view of the accelerator according to an embodiment of the present disclosure, and FIG. 3 is a longitudinal cross-sectional view of the accelerator according to an embodiment of the present disclosure taken along line AA in FIG. 2.

[0014] 1 to 3, the accelerator 1 of this embodiment is an accelerator that accelerates charged particles and emits them as a beam (ion beam), and is, for example, a superconducting cyclotron or a superconducting synchrocyclotron, etc. However, the accelerator 1 is not limited to these examples.

[0015] The accelerator 1 has a superconducting magnet 10 with an iron core. The superconducting magnet 10 with an iron core is a main magnetic field generating device that generates a main magnetic field for circulating the beam, and has a substantially cylindrical iron core (return yoke) 11. The iron core 11 is configured so as to be separable into upper and lower parts across an iron core dividing plane P, which is a substantially horizontal plane passing through the approximate center in the vertical direction.

[0016] The iron core 11 is provided with supporting legs 12 that support the iron core 11, and a lifter 13 that raises and lowers the upper part of the iron core 11 in order to separate the iron core 11 into upper and lower parts. There may be a plurality of supporting legs 12.

[0017] 3, an acceleration space 20 is formed inside the iron core 11, which is symmetrical above and below the iron core dividing plane P. In the acceleration space 20, a main magnetic field oriented in the vertical direction is generated by the superconducting magnet 10 with an iron core, and the beam orbits within the acceleration space 20 due to the main magnetic field.

[0018] 3, inside the core 11, two superconducting coils 21 for generating a main magnetic field are arranged substantially symmetrically with respect to the core dividing plane P. Each superconducting coil 21 is housed in a coil frame 22. The coil frame 22 is surrounded by a coil section shield plate 23 that blocks radiant heat from the outside. Furthermore, the superconducting coil 21, the coil frame 22 and the coil section shield plate 23 are contained in a coil section vacuum vessel 24 that keeps the inside in a vacuum state.

[0019] Further, refrigerators 25 are provided on the upper and lower parts of the core 11 for cooling the superconducting coils 21 to a temperature below the temperature at which the superconducting coils 21 exhibit complete diamagnetism. The refrigerator 25 provided on the upper part cools the superconducting coils 21 arranged above the core division surface P, and the refrigerator 25 provided on the lower part cools the superconducting coils 21 arranged above the core division surface P. In this embodiment, a total of four refrigerators 25 are provided, two on the top and two on the bottom, but the number of refrigerators 25 is not limited to this example.

[0020] Refrigerator 25 includes refrigerator port 26 extending into coil vacuum vessel 24, and is thermally coupled to superconducting coil 21 inside coil shield plate 23 via refrigerator port 26. Refrigerator port 26 is surrounded by port shield plate 27 that blocks radiant heat from the outside. Furthermore, port shield plate 27 is contained within port vacuum vessel 28, the inside of which is kept in a vacuum state.

[0021] The coil section vacuum vessel 24 and the port section vacuum vessel 28 are used not only to create a vacuum state inside, but also as vacuum vessels to create a vacuum state in the space surrounded by the coil section vacuum vessel 24 and the port section vacuum vessel 28, including the acceleration space 20. This space is evacuated by a vacuum pump (not shown). Since the coil section vacuum vessel 24 and the port section vacuum vessel 28 are installed in a vacuum state inside, there is no need to connect them to a vacuum pump.

[0022] 4 to 6 are diagrams for explaining heat generating devices in accelerator 1 and a cooling structure for cooling the heat generating devices.

[0023] 4 is a top view of the configuration on the core division plane P of the accelerator 1. As shown in FIG. 4, an acceleration space 20 is formed so as to be surrounded by a vacuum vessel (coil section vacuum vessel 24), and the acceleration space 20 has a beam acceleration electrode 30 that generates an accelerating electric field for accelerating the beam circulating in the acceleration space 20. The beam acceleration electrode 30 is, for example, a radio frequency acceleration cavity. This allows the beam to be accelerated while circulating in the acceleration space 20 until it has a desired energy.

[0024] Also installed in the acceleration space 20 are a beam extraction device 50 for extracting the beam circulating in the acceleration space 20 to the outside, and a radio frequency kicker 55 for disturbing the beam circulating in the acceleration space 20 to excite an electric field that guides the beam to the beam extraction device 50. Also, a coaxial cable 56 is connected to the radio frequency kicker 55 as a cable for supplying a drive signal for driving the radio frequency kicker 55.

[0025] The beam extraction device 50 generates heat due to the collision of the beam, and the coaxial cable 56 generates heat due to the drive signal. Therefore, the beam extraction device 50 and the coaxial cable 56 become heat-generating devices that generate heat. In addition, a cooling structure for cooling the heat-generating devices is formed in a part of the coil unit vacuum vessel 24.

[0026] FIG. 5 is a diagram for explaining the beam extraction device 50, which is a heat generating device, and a method for cooling it. FIG. 6 is a diagram for explaining the coaxial cable 56, which is a heat generating device, and a method for cooling it.

[0027] As shown in Figs. 4 to 6, the accelerator 1 is provided with a plurality of ducts 60 for drawing out the coaxial cables 56 and the beams to the outside. In this embodiment, at least a part of the wall surface of the duct 60 for drawing out the coaxial cables 56 is formed of a heat sink 61 which is a cooling structure. The heat sink 61 and the beam extraction device 50 are thermally coupled to each other via a heat transfer member 70. The coaxial cables 56 are thermally coupled to the heat sink 61 by being disposed on the wall surface of the duct 60 formed of the heat sink 61.

[0028] The beam extraction device 50 and the coaxial cable 56 are examples of heat generating devices, and the heat generating devices are not limited to these, and may be other devices that require cooling. For example, the heat generating devices may include devices for accelerating the beam, such as the beam acceleration electrode 30. In this embodiment, the plurality of heat generating devices (the beam extraction device 50 and the coaxial cable 56) are thermally coupled to the same heat sink 61, but a separate heat sink may be provided for each heat generating device. The heat sink 61 does not have to be formed in the duct 60 as long as it is formed as a part of the vacuum vessel.

[0029] Fig. 7 is a diagram showing an example of a heat sink 61. Specifically, Fig. 7(a) is a bottom view of the heat sink 61, Fig. 7(b) is a right side view of the heat sink 61, and Fig. 7(c) is a front view of the heat sink 61.

[0030] The heat sink 61 shown in Fig. 7 has a supply port 62 to which water, which is a refrigerant (cooling medium) for cooling a heat-generating device, is supplied, a refrigerant flow path 63 through which the water supplied to the supply port 62 passes, and an outlet 64 through which the water that has flowed through the refrigerant flow path 63 is discharged. In the example of Fig. 7, the refrigerant flow path 63 is arranged in a serpentine manner, but is not limited to this example. Moreover, the heat sink 61 is formed such that the supply port 62 and the outlet 64 are provided outside the vacuum container (24).

[0031] The heat sink 61 is composed of a substrate 65 in which a coolant flow path 63 is formed, and a lid 66 that covers the substrate 65. The substrate 65 and the lid 66 are joined together by, for example, welding.

[0032] As described above, according to this embodiment, the vacuum vessel (24) surrounds the acceleration space (20) in which charged particles are accelerated, and the acceleration space 20 is placed in a vacuum state. The heat-generating devices (50, 56) are disposed inside the vacuum vessel (24). The cooling structure (61) for cooling the heat-generating devices (50, 56) is formed as part of the vacuum vessel (24). This eliminates the need to provide piping or the like for cooling the heat-generating devices inside the vacuum vessel, and thus simplifies the cooling structure for cooling the heat-generating devices.

[0033] In the present embodiment, the vacuum vessel 24 has a duct 60, and the cooling structure 61 is formed as at least a part of the wall surface of the duct 60. In this case, it is possible to easily form the cooling structure as a part of the vacuum vessel.

[0034] In the present embodiment, the cooling structure (61) is a heat sink, particularly a heat sink having a refrigerant flow path (63) through which a refrigerant passes, and a refrigerant supply port 62 and a refrigerant discharge port 64 are provided outside the vacuum container (24). This makes it possible to easily supply and discharge the refrigerant. It also makes it possible to further prevent the refrigerant from leaking into the vacuum container.

[0035] In addition, in this embodiment, the multiple heat generating devices 50, 56 are thermally coupled to a single heat sink 61. In this case, it is possible to further simplify the cooling structure.

[0036] In this embodiment, the heat generating device is the beam extraction device 50, and the beam extraction device 50 and the cooling structure 61 are thermally coupled via a heat transfer member 70. This makes it possible to appropriately cool the beam extraction device 50.

[0037] In this embodiment, the heat-generating device is the coaxial cable 56 of the high-frequency kicker 55, and the coaxial cable 56 is disposed on the cooling structure 61. This makes it possible to easily cool the coaxial cable 56.

[0038] The above-described embodiments of the present disclosure are illustrative examples of the present disclosure, and are not intended to limit the scope of the present disclosure to only these embodiments. A person skilled in the art can implement the present disclosure in various other forms without departing from the scope of the present disclosure. [Explanation of symbols]

[0039] 1: accelerator 10: superconducting magnet with iron core 11: iron core 12: support leg 13: lifter 20: acceleration space 21: superconducting coil 22: coil frame 23: coil shield plate 24: coil vacuum vessel 25: refrigerator 26: refrigerator port 27: port shield plate 28: port vacuum vessel 30: beam acceleration electrode 50: beam extraction device 55: high frequency kicker 56: coaxial cable 60: duct 61: heat sink 62: supply port 63: coolant flow path 64: exhaust port 65: substrate 66: lid 70: heat transfer member

Claims

1. An accelerator that accelerates and emits charged particles, a vacuum vessel that encloses an acceleration space in which the charged particles are accelerated and that places the acceleration space in a vacuum state; A heat generating device disposed inside the vacuum vessel; a cooling structure for cooling the heat generating device, The accelerator, wherein the cooling structure is formed as part of the vacuum vessel.

2. the vacuum vessel has a duct; The accelerator of claim 1 , wherein the cooling structure is formed as at least a portion of a wall of the duct.

3. The accelerator of claim 1 , wherein the cooling structure is a heat sink.

4. the heat sink includes a supply port through which a coolant is supplied, a coolant flow path through which the coolant supplied to the supply port passes, and a discharge port through which the coolant that has flowed through the coolant flow path is discharged; The accelerator according to claim 3 , wherein the supply port and the exhaust port are provided outside the vacuum vessel.

5. The accelerator of claim 3 , wherein a plurality of said heat generating devices are thermally coupled to the same said heat sink.

6. the heat generating device is an extraction device for extracting the charged particles to the outside, The accelerator of claim 1 , wherein the removal device and the cooling structure are thermally coupled via a heat transfer member.

7. the heat generating device is a cable that supplies a drive signal for driving a high frequency kicker that guides the charged particles to an extraction device for extracting the charged particles to the outside, The accelerator of claim 1 , wherein the cable is disposed on the cooling structure.

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