Superconducting magnet apparatus and busbar assembly for superconducting magnet apparatus

Abstract

The bus assembly (20) for the superconducting magnet device includes an outer bus (40a) and an inner bus (40b). The outer bus (40a) connects the first superconducting coil side cable (34a) to the first power supply side cable (36a), and together with the first superconducting coil side cable (34a) and the first power supply side cable (36a), forms an outer deflection path (44a). The inner bus (40b) connects the second superconducting coil side cable (34b) to the second power supply side cable (36b), and together with the second superconducting coil side cable (34b) and the second power supply side cable (36b), forms an inner deflection path (44b). The outer deflection path (44a) and the inner deflection path (44b) deflect in parallel, and the path length of the outer deflection path (44a) is greater than the path length of the inner deflection path (44b).

Description

Technical Field

[0001] This invention relates to a superconducting magnet device and a bus assembly for a superconducting magnet device. Background Technology

[0002] Typically, a superconducting magnet device comprises a superconducting coil and a vacuum container, which houses the superconducting coil while it is cooled to an ultra-low temperature. The power supply for the superconducting coil is located outside the vacuum container. Coil electrodes connected to the superconducting coil are disposed on the outside of the vacuum container, and the power supply and coil electrodes are connected via a feed cable.

[0003] Previous technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2013-258116 Summary of the Invention

[0004] The technical problem to be solved by the invention The inventors of this application studied the aforementioned superconducting magnet device and discovered the following problems. At least a portion of the feed cable is laid along a predetermined path on the outside of the vacuum container. The path of the feed cable may include at least one cable deflection point. With the miniaturization of superconducting magnet devices developed in recent years, the area on the surface of the vacuum container where the feed cable can be placed has decreased, thus it is desirable for the bending radius of the feed cable at the cable deflection point to also decrease. However, the feed cable must be deflected with a bending radius greater than the allowable bending radius specified in its specifications. Such limitations may hinder the saving of cable placement space.

[0005] One exemplary objective of one embodiment of the present invention is to provide a technique that helps save cable configuration space in a superconducting magnet device.

[0006] means for solving technical problems According to one embodiment of the present invention, a superconducting magnet device includes: a superconducting coil; a power supply; a first superconducting coil side cable and a second superconducting coil side cable connected to the superconducting coil; a first power supply side cable and a second power supply side cable connected to the power supply; and a bus assembly having an outer bus and an inner bus. The outer bus connects the first superconducting coil side cable to the first power supply side cable, and together with the first superconducting coil side cable and the first power supply side cable, forms an outer deflection path. The inner bus connects the second superconducting coil side cable to the second power supply side cable, and together with the second superconducting coil side cable and the second power supply side cable, forms an inner deflection path. The outer deflection path and the inner deflection path deflect in parallel, and the path length of the outer deflection path is greater than the path length of the inner deflection path.

[0007] According to one embodiment of the present invention, a bus assembly for a superconducting magnet device includes: an outer bus that connects a first superconducting coil-side cable to a first power supply-side cable and forms an outer deflection path together with the first superconducting coil-side cable and the first power supply-side cable; and an inner bus that connects a second superconducting coil-side cable to a second power supply-side cable and forms an inner deflection path together with the second superconducting coil-side cable and the second power supply-side cable. The outer deflection path and the inner deflection path deflect in parallel, and the path length of the outer deflection path is greater than the path length of the inner deflection path.

[0008] Invention Effects According to the present invention, a technique is provided that helps to save cable configuration space in superconducting magnet devices. Attached Figure Description

[0009] Figure 1 This is a schematic diagram illustrating the superconducting magnet device involved in the embodiment.

[0010] Figure 2 It is shown schematically. Figure 1 A cross-sectional view of the AA line section of the superconducting magnet device shown.

[0011] Figure 3 This is a top view schematically illustrating an example of a busbar assembly that can be mounted on a superconducting magnet device according to an embodiment.

[0012] Figure 4 This is an example of the action applied to Figure 3 A schematic diagram of the forces acting on the busbar assembly shown.

[0013] Figure 5 This is a top view schematically illustrating another example of a bus assembly involved in the implementation.

[0014] Figure 6 This is a top view schematically illustrating another example of a bus assembly involved in the implementation.

[0015] Figure 7 This is a top view schematically illustrating another example of a bus assembly involved in the implementation.

[0016] Figure 8 This is a top view schematically illustrating another example of a bus assembly involved in the implementation. Detailed Implementation

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description and drawings, the same or equivalent constituent elements, components, and processes are labeled with the same reference numerals, and repeated descriptions are omitted where appropriate. The scaling and shapes of the illustrated parts are schematic for ease of explanation and should not be interpreted as limiting unless otherwise specified. The embodiments are illustrative and do not limit the scope of the present invention in any way. All features or combinations thereof described in the embodiments are not necessarily essential features of the present invention.

[0018] Figure 1 This is a schematic diagram illustrating the superconducting magnet device 10 according to the embodiment. Figure 2 It is shown schematically. Figure 1 The diagram shows a cross-sectional view of the superconducting magnet device 10 along line AA. As an example, the superconducting magnet device 10 can be mounted on a high magnetic field utilization device, such as a cyclotron, synchrotron, or other high magnetic field utilization device, to generate the high magnetic field required by that device.

[0019] The superconducting magnet device 10 includes: a superconducting coil 12; a power supply 13 for the superconducting coil 12; a vacuum container 14 for housing the superconducting coil 12; a current lead 16 connected to the superconducting coil 12 and disposed in the vacuum container 14; a feed cable 18 disposed on the outside of the vacuum container 14 and connecting the power supply 13 and the current lead 16; and a bus assembly 20 disposed in the vacuum container 14 for wiring the feed cable 18.

[0020] like Figure 2 As shown, a pair of superconducting coils 12 can be provided in the superconducting magnet device 10. The two superconducting coils 12 have the same diameter annular shape centered on the central axis C, and are spaced apart from each other in the axial direction (direction of the central axis C). The superconducting coils 12 are capable of generating an axial magnetic field on their radially inner side.

[0021] Vacuum container 14 provides an ultra-low temperature vacuum environment 22 within its internal space suitable for placing the superconducting coil 12 in a superconducting state. Vacuum container 14 is, for example, a cryostat. As an example, vacuum container 14 may have a cylindrical shape surrounding the superconducting coil 12. Vacuum container 14 is made of a metallic material such as stainless steel or other suitable high-strength material to withstand ambient pressure (e.g., atmospheric pressure). Within the ultra-low temperature vacuum environment 22 inside vacuum container 14, a heat shield 24 surrounding the superconducting coil 12 is also provided to reduce thermal intrusion into the superconducting coil 12. In this example, two heat shields 24 are provided corresponding to each pair of superconducting coils 12.

[0022] Furthermore, a pair of magnetic poles 26 disposed in the hollow portion of the vacuum container 14, and a magnetic yoke 28 forming a magnetic circuit together with the magnetic poles 26, are provided. These two magnetic poles 26 are respectively disposed inside the corresponding superconducting coils 12, forming a superconducting electromagnet with an iron core. The magnetic yoke 28 has an upper magnetic yoke 28a and a lower magnetic yoke 28b, surrounding the vacuum container 14. When the superconducting magnet device 10 is used as a cyclotron, it can be disposed in the gap 30 between the magnetic poles 26. Figure 2 The ion source and accelerating electrode are omitted from the diagram.

[0023] The superconducting coil 12 is thermally connected, for example, to a two-stage Gifford-McMahon (GM) cryo-crystal or other type of cryogenic cryo-crystal 32, and is used in a cryogenic state cooled to below the superconducting transition temperature. The heat shield 24 can be cooled to a first cooling temperature, for example, 30K to 80K, by the high-temperature stage cooling platform of the cryogenic cryo-crystal 32, and the superconducting coil 12 can be cooled to a second cooling temperature, for example, 3K to 20K, below the first cooling temperature, by the low-temperature stage cooling platform. In this example, the superconducting magnet device 10 is configured as a so-called conduction-cooled type, that is, the superconducting coil 12 is directly cooled by the cryogenic cryo-crystal 32, but it can also be cooled by a so-called immersion-cooled type, that is, the superconducting coil 12 is cooled by a cryogenic liquid refrigerant such as liquid helium.

[0024] The power supply 13 is located outside the vacuum container 14 and is electrically connected to the superconducting coil 12 via current leads 16 and feed cables 18. Excitation current is supplied from the power supply 13 to the superconducting coil 12 via the current leads 16 and feed cables 18. Thus, the superconducting magnet device 10 can generate a strong magnetic field. The power supply 13 can be located in a separate building or room from the vacuum container 14.

[0025] The current leads 16 are arranged in pairs, at least on the positive and negative sides. For example... Figure 1 As shown, an airtight terminal 16a is provided at the end of the current lead 16 on the ambient side (room temperature side) for introducing current into the vacuum container 14 by penetrating the wall of the vacuum container 14. In the illustrated example, the airtight terminal 16a is provided on the upper surface of the vacuum container 14, but this configuration is not limited to. The opposite end (low temperature side) of the current lead 16 is connected to the superconducting coil 12 inside the vacuum container 14.

[0026] The power supply cable 18 includes a first superconducting coil side cable 34a and a second superconducting coil side cable 34b connected to the superconducting coil 12, and a first power supply side cable 36a and a second power supply side cable 36b connected to the power supply 13. The first superconducting coil side cable 34a and the second superconducting coil side cable 34b extend parallel to each other and are connected to the busbar assembly 20 at least in the vicinity of the busbar assembly 20. Similarly, the first power supply side cable 36a and the second power supply side cable 36b extend parallel to each other and are connected to the busbar assembly 20 at least in the vicinity of the busbar assembly 20.

[0027] In this example, the first superconducting coil side cable 34a and the first power supply side cable 36a are used as feed lines on the positive side, and the second superconducting coil side cable 34b and the second power supply side cable 36b are used as feed lines on the negative side. Therefore, one end of the first superconducting coil side cable 34a is connected to the hermetically sealed terminal 16a of the current lead 16 on the positive side, and the other end is connected to one end of the first power supply side cable 36a via the bus assembly 20. The other end of the first power supply side cable 36a is connected to the positive terminal of the power supply 13. Similarly, one end of the second superconducting coil side cable 34b is connected to the hermetically sealed terminal 16a of the current lead 16 on the negative side, and the other end is connected to one end of the second power supply side cable 36b via the bus assembly 20. The other end of the second power supply side cable 36b is connected to the negative terminal of the power supply 13. Alternatively, in contrast to this example, the first superconducting coil side cable 34a and the first power supply side cable 36a could be used as feed lines on the negative side, and the second superconducting coil side cable 34b and the second power supply side cable 36b could be used as feed lines on the positive side.

[0028] The first superconducting coil side cable 34a and the second superconducting coil side cable 34b can also be supported by a flexible cable support 38. As described above, the yoke 28 can have an upper yoke 28a and a lower yoke 28b. In order to ensure the working space for external access to the vacuum container 14 when maintaining the superconducting magnet device 10, the yoke 28 can be configured to allow the upper yoke 28a to move upward away from the lower yoke 28b. One end of the cable support 38 is connected to the upper yoke 28a and the other end is connected to the lower yoke 28b, and it can support these feed cables to allow the first superconducting coil side cable 34a and the second superconducting coil side cable 34b to move along with the upper yoke 28a relative to the lower yoke 28b.

[0029] As described below, bus assembly 20 provides a cable routing structure that allows the feed cable 18 to deflect at any angle (90 degrees in the example) along the surface of vacuum container 14. As an illustrative configuration, bus assembly 20 may be disposed on the surface of yoke 28. In the illustrated example, bus assembly 20 is disposed, for example, on the side of lower yoke 28b.

[0030] Figure 3This is a top view schematically illustrating an example of a bus assembly 20 that can be mounted on a superconducting magnet device 10 according to an embodiment. The bus assembly 20 has multiple buses, such as an outer bus 40a and an inner bus 40b. The outer bus 40a and the inner bus 40b are arranged in parallel. These buses are formed, for example, by good conductors such as copper or aluminum. Furthermore, the bus assembly 20 has a support body 42 having a support surface 42a. The support body 42 can be formed, for example, by a metal material such as stainless steel or other suitable materials. The outer bus 40a and the inner bus 40b are respectively supported on the support surface 42a by an insulating material on the support body 42.

[0031] The outer bus 40a connects the first superconducting coil side cable 34a to the first power supply side cable 36a, and together with the first superconducting coil side cable 34a and the first power supply side cable 36a, forms an outer deflection path 44a. The inner bus 40b connects the second superconducting coil side cable 34b to the second power supply side cable 36b, and together with the second superconducting coil side cable 34b and the second power supply side cable 36b, forms an inner deflection path 44b.

[0032] The outer deflection path 44a and the inner deflection path 44b deflect in parallel. The outer deflection path 44a deflects 90 degrees along the support surface 42a from the starting point A1 to the ending point B1. The inner deflection path 44b deflects 90 degrees along the support surface 42a from the starting point A2 to the ending point B2, inside the outer deflection path 44a.

[0033] Therefore, the path length of the outer deflection path 44a (i.e., the length along the outer deflection path 44a from its starting point A1 to its ending point B1) is greater than the path length of the inner deflection path 44b (i.e., the length along the inner deflection path 44b from its starting point A2 to its ending point B2). To achieve this, the length L1 of the outer busbar 40a along the outer deflection path 44a is greater than the length L2 of the inner busbar 40b along the inner deflection path 44b.

[0034] In this example, the direction of the feed cable 18 is switched using the outer bus 40a and the inner bus 40b, so the feed cable 18 itself does not bend near the bus assembly 20 due to cable deflection. The first superconducting coil side cable 34a is installed at one end of the outer bus 40a at a 90-degree angle to it, and the second superconducting coil side cable 34b is installed at one end of the inner bus 40b at a 90-degree angle to it. The first superconducting coil side cable 34a and the second superconducting coil side cable 34b extend in a straight line from the outer bus 40a and the inner bus 40b, respectively. Furthermore, the first power supply side cable 36a extends in a straight line from the other end of the outer bus 40a along its length, and the second power supply side cable 36b extends in a straight line from the other end of the inner bus 40b along its length.

[0035] For ease of understanding, Figure 1 The permissible bending radius R of the feeder cable 18 is shown in the specification. In other words, the feeder cable 18 is not allowed to deflect with a bending radius smaller than the permissible bending radius R. The permissible bending radius R of the feeder cable 18 may have a certain size, such as... Figure 3 As shown, the bending radius r achievable by the bus assembly 20 can be smaller than the allowable bending radius R. This is because, as described above, the cable direction can be switched using the outer bus 40a and the inner bus 40b without bending the feeder cable 18 itself. Furthermore, the feeder cable 18 can also be bent to a certain extent when wiring is required.

[0036] Thus, the bus assembly 20 involved in the embodiment can confine the deflection of the feed cable 18 to a smaller space. Therefore, according to the embodiment, it can be applied to the miniaturization of the superconducting magnet device 10, achieving space-saving cable configuration.

[0037] Figure 4 This is an example of the action applied to Figure 3 This is a schematic diagram of the forces acting on the bus assembly 20. In this example, as described above, the first superconducting coil side cable 34a, the outer bus 40a, and the first power supply side cable 36a are connected to the positive terminal of the power supply 13, while the second superconducting coil side cable 34b, the inner bus 40b, and the second power supply side cable 36b are connected to the negative terminal of the power supply 13. When the superconducting coil 12 is energized by the power supply 13, the current I1 flowing through the outer bus 40a and the current I2 flowing through the inner bus 40b are of the same magnitude but opposite in direction. The magnetic field B generated by the superconducting coil 12 can have a direction along the support surface 42a of the support body 42 around the bus assembly 20.

[0038] The force F1 generated by current I1 and magnetic field B and acting on the outer busbar 40a is opposite in direction to the force F2 generated by current I2 and magnetic field B and acting on the inner busbar 40b, and they can at least partially cancel each other out. Therefore, the resultant force acting on the support 42 is reduced. The fixing force (e.g., bolt tightening force in the case of bolt fixing) for fixing the busbar assembly 20 to the vacuum container 14 can be reduced, and the fixing structure of the busbar assembly 20 can be simplified. This advantage can be obtained by connecting one of the first power supply cable 36a and the second power supply cable 36b to the positive terminal of the power supply 13, and the other of the first power supply cable 36a and the second power supply cable 36b to the negative terminal of the power supply 13.

[0039] And, as Figure 3 As shown, the outer bus 40a and the inner bus 40b can be supported with a specified bus spacing D. The bus spacing D can be set such that, when the superconducting magnet device 10 is operating at its rated current, the electric field generated between the outer bus 40a and the inner bus 40b is below a specified upper limit value. Here, the specified upper limit value of the bus spacing electric field can be set from the viewpoint of preventing discharge between the outer bus 40a and the inner bus 40b. For example, the specified upper limit value of the bus spacing electric field can be 0.1 kV / m or more, or 1 kV / m or more. For example, the specified upper limit value of the bus spacing electric field can be 100 mV / m or less, 100 kV / m or less, or 10 kV / m or less.

[0040] Figure 5 This is a top view schematically illustrating another example of the bus assembly 20 according to the embodiment. As shown, the bus assembly 20 may include an insulating member 46 disposed between the outer bus 40a and the inner bus 40b. The insulating member 46 may also be a wall provided on the support 42 to separate the outer bus 40a and the inner bus 40b. The insulating member 46 may be formed, for example, of fiber reinforced plastic (FRP) such as glass fiber reinforced plastic (GFRP) or other suitable insulating materials. In this way, the risk of discharge between the outer bus 40a and the inner bus 40b can also be reduced.

[0041] The present invention has been described above with reference to embodiments. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and various design changes and modifications are possible, and these modifications are also included within the scope of the present invention. Various features described in conjunction with certain embodiments can also be applied to other embodiments. New embodiments resulting from combinations possess the effects of the combined embodiments.

[0042] In the above embodiments, an example is given of a one-to-one connection between the feed cable 18 on the superconducting coil 12 side and the feed cable 18 on the power supply 13 side via a bus assembly 20, but the present invention is not limited thereto. See the following references... Figure 6 The busbar assembly 20 can be configured to branch or flow the feeder cable 18.

[0043] Figure 6 This is a top view schematically illustrating another example of the bus assembly 20 involved in the embodiment. As shown, the first power-side cable 36a may include multiple power-side cables, and the outer bus 40a may branch the first superconducting coil-side cable 34a into multiple power-side cables. Similarly, the second power-side cable 36b may also include multiple power-side cables. The inner bus 40b may also branch the second superconducting coil-side cable 34b into multiple power-side cables.

[0044] Although the illustration is omitted, the first superconducting coil side cable 34a can also include multiple coil side cables, and the outer busbar 40a can branch the first power supply side cable 36a into multiple coil side cables. The second superconducting coil side cable 34b can include multiple coil side cables, and the inner busbar 40b can branch the second power supply side cable 36b into multiple coil side cables.

[0045] In the above embodiments, an example was given of bus assembly 20 having two buses (40a, 40b), but the present invention is not limited thereto. See the following references... Figure 7 As described, bus assembly 20 may have three or more buses, through which three or more feed cables 18 can be deflected. The length of these buses can be set such that the longer the bus is located on the outer periphery of the cable deflection.

[0046] Figure 7 This is a top view schematically illustrating another example of the bus assembly 20 according to the embodiment. In addition to the outer bus 40a and the inner bus 40b, the bus assembly 20 may also include a third bus 40c. The third bus 40c can connect the third superconducting coil side cable 34c to the third power supply side cable 36c by switching the direction of the third superconducting coil side cable 34c relative to the third power supply side cable 36c. The third bus 40c may be shorter than the inner bus 40b, or it may be positioned further inward than the inner bus 40b.

[0047] The third superconducting coil side cable 34c and the third power supply side cable 36c can also be third feed cables connecting the superconducting coil 12 to the power supply 13. The superconducting magnet device 10 may also have other electrical equipment different from the superconducting coil 12, such as auxiliary superconducting coils, normal conducting coils, and measuring equipment. The third superconducting coil side cable 34c and the third power supply side cable 36c can also be feed cables connecting these devices to the power supply 13.

[0048] Figure 8 This is a top view schematically illustrating another example of the bus assembly 20 involved in the embodiment. Figure 7 Similarly, in the example, Figure 8 In the example, bus assembly 20 includes an outer bus 40a, an inner bus 40b, and a third bus 40c. As shown, bus assembly 20 can utilize these three buses to achieve a 180-degree cable deflection in a space-saving manner.

[0049] If necessary, multiple busbar assemblies 20 can be provided in the superconducting magnet device 10. For example, when there are multiple deflection points in the path of the feed cable 18, a busbar assembly 20 can be provided at each deflection point.

[0050] Based on the implementation methods, the present invention has been described using specific statements. However, the implementation methods only represent one aspect of the principle and application of the present invention. Many modifications or configuration changes can be made to the implementation methods without departing from the spirit of the present invention as defined in the claims.

[0051] Industrial availability This invention can be applied to the field of superconducting magnet devices and busbar assemblies for superconducting magnet devices.

[0052] Symbol Explanation 10-Superconducting magnet device, 12-Superconducting coil, 13-Power supply, 20-Bus assembly, 34a-First superconducting coil side cable, 34b-Second superconducting coil side cable, 36a-First power supply side cable, 36b-Second power supply side cable, 40a-Outer bus, 40b-Inner bus, 42-Support body, 44a-Outer deflection path, 44b-Inner deflection path, 46-Insulating component.

Claims

1. A superconducting magnet device, characterized in that, have: Superconducting coils; power supply; The first superconducting coil side cable and the second superconducting coil side cable are connected to the superconducting coil; The first power supply side cable and the second power supply side cable are connected to the power supply. as well as Bus assembly, having an outer bus and an inner bus, The outer busbar connects the first superconducting coil side cable to the first power supply side cable, and together with the first superconducting coil side cable and the first power supply side cable, forms an outer deflection path. The inner busbar connects the second superconducting coil side cable to the second power supply side cable, and together with the second superconducting coil side cable and the second power supply side cable, forms an inner deflection path. The outer deflection path and the inner deflection path deflect in parallel, and the path length of the outer deflection path is greater than the path length of the inner deflection path.

2. The superconducting magnet device according to claim 1, characterized in that, The length of the outer busbar along the outer deflection path is greater than the length of the inner busbar along the inner deflection path.

3. The superconducting magnet device according to claim 1 or 2, characterized in that, The bus assembly includes a support body that supports the outer bus and the inner bus at a bus spacing of such spacing that the bus spacing is set such that when the superconducting magnet device is operating at its rated current, the electric field generated between the outer bus and the inner bus is below a predetermined upper limit.

4. The superconducting magnet device according to claim 1 or 2, characterized in that, The bus assembly includes an insulating member disposed between the outer bus and the inner bus.

5. The superconducting magnet device according to claim 1 or 2, characterized in that, The bus assembly is configured such that the electromagnetic force acting on the outer bus when the superconducting coil is energized by the power source at least partially cancels out the electromagnetic force acting on the inner bus when the superconducting coil is energized by the power source.

6. The superconducting magnet device according to claim 1 or 2, characterized in that, One of the first power-side cable and the second power-side cable is connected to the positive terminal of the power supply, and the other of the first power-side cable and the second power-side cable is connected to the negative terminal of the power supply.

7. The superconducting magnet device according to claim 1 or 2, characterized in that, The first power-side cable and the second power-side cable each include multiple cables.

8. The superconducting magnet device according to claim 1 or 2, characterized in that, The bus assembly also includes a third bus that connects the third superconducting coil side cable to the third power supply side cable.

9. The superconducting magnet device according to claim 1 or 2, characterized in that, The bus assembly deflects the first superconducting coil side cable by 90 degrees relative to the first power supply side cable and deflects the second superconducting coil side cable by 90 degrees relative to the second power supply side cable.

10. The superconducting magnet device according to claim 1 or 2, characterized in that, The bus assembly deflects the first superconducting coil side cable by 180 degrees relative to the first power supply side cable and deflects the second superconducting coil side cable by 180 degrees relative to the second power supply side cable.

11. A bus assembly for a superconducting magnet device, characterized in that, have: The outer busbar connects the first superconducting coil side cable to the first power supply side cable, and together with the first superconducting coil side cable and the first power supply side cable, forms an outer deflection path. as well as The inner busbar connects the second superconducting coil side cable to the second power supply side cable, and together with the second superconducting coil side cable and the second power supply side cable, forms an inner deflection path. The outer deflection path and the inner deflection path deflect in parallel, and the path length of the outer deflection path is greater than the path length of the inner deflection path.

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