Superconducting magnet

Abstract

The present invention reduces quench risk for a superconducting magnet.　A superconducting magnet (101) according to an embodiment comprises: a bobbin (20) that holds a superconducting coil (10); and a thermally conductive material that extends from a first portion, which is a portion of the outer peripheral surface of the bobbin (20) that corresponds to the portion of the bobbin (20) where the superconducting coil (10) is disposed, to a second portion, which is a portion of the outer peripheral surface of the bobbin (20) that corresponds to the portion of the bobbin (20) where the superconducting coil (10) is not disposed.

Description

Superconducting magnet

[0001] The embodiments disclosed in this specification and the drawings relate to a superconducting magnet.

[0002] During the scan of a magnetic resonance imaging apparatus, eddy currents may be generated by the pulsed leakage magnetic field from the gradient magnetic field coil, which may cause the superconducting coil to generate heat. This mechanism is generally known as the GCIH phenomenon (Gradient Coil Induced Heating). When the superconducting coil generates heat due to the GCIH phenomenon, the superconducting coil may quench and the superconducting state of the superconducting coil may be broken.

[0003] Here, in order to reduce the quench risk of the superconducting coil, methods such as reducing the leakage magnetic field of the gradient magnetic field coil, suppressing the mechanical vibration of the thermal shield, and increasing the quench margin of the superconducting coil can be considered. However, for example, when higher image quality is required, since it is necessary to increase the output of the gradient magnetic field coil, it is desirable to take separate countermeasures.

[0004] Japanese Patent Application Laid-Open No. 2-195937

[0005] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to reduce the quench risk of the superconducting magnet. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problems. The problems corresponding to the respective effects of each configuration shown in the embodiments described later can also be positioned as other problems.

[0006] The superconducting magnet according to the embodiment includes a bobbin that holds a superconducting coil, and a heat conductive material that extends from a first portion on the outer peripheral surface of the bobbin corresponding to a portion of the bobbin where the superconducting coil is disposed to a second portion on the outer peripheral surface of the bobbin corresponding to a portion of the bobbin where the superconducting coil is not disposed.

[0007] Figure 1 shows an example of the configuration of a magnetic resonance imaging apparatus having a superconducting magnet according to an embodiment. Figure 2 shows an example of the configuration of a superconducting magnet according to the first embodiment. Figure 3 is an enlarged view showing a part of Figure 2. Figure 4 shows an example of the configuration of a superconducting magnet according to the first embodiment. Figure 5 shows an example of the arrangement of a heat conductive material according to the first embodiment. Figure 6 shows an example of the configuration of a superconducting magnet according to the second embodiment. Figure 7 shows an example of the configuration of a superconducting magnet according to the second embodiment.

[0008] (First Embodiment) Hereinafter, embodiments of the superconducting magnet will be described in detail with reference to the drawings. Figure 1 is a block diagram of a magnetic resonance imaging apparatus 100 having a superconducting magnet according to the first embodiment. As shown in Figure 1, the magnetic resonance imaging apparatus 100 includes a superconducting magnet 101, a static magnetic field power supply (not shown), a gradient magnetic field coil 103, a gradient magnetic field power supply 104, a bed 105, a bed control circuit 106, a transmitting coil 107, a transmitting circuit 108, a receiving coil 109, a receiving circuit 110, a sequence control circuit 120 (sequence control unit), and a computer 130 (also referred to as an "image processing device"). Note that the magnetic resonance imaging apparatus 100 does not include a subject P (for example, a human body). Furthermore, the configuration shown in Figure 1 is merely an example. For example, the parts within the sequence control circuit 120 and the computer 130 may be integrated or separated as appropriate.

[0009] The superconducting magnet 101 is a static magnetic field magnet formed in a hollow, approximately cylindrical shape, and generates a static magnetic field in its internal space. The detailed structure of the superconducting magnet 101 will be described in detail using Figures 2 to 5.

[0010] The gradient magnetic field coil 103 is a hollow, substantially cylindrical coil and is placed inside the superconducting magnet 101. The gradient magnetic field coil 103 is formed by combining three coils corresponding to the mutually orthogonal X, Y, and Z axes. These three coils receive current individually from the gradient magnetic field power supply 104, generating gradient magnetic fields in which the magnetic field strength changes along the X, Y, and Z axes. The gradient magnetic fields in the X, Y, and Z axes generated by the gradient magnetic field coil 103 are, for example, a slicing gradient magnetic field Gs, a phase encoding gradient magnetic field Ge, and a readout gradient magnetic field Gr. The gradient magnetic field power supply 104 supplies current to the gradient magnetic field coil 103.

[0011] The bed 105 is equipped with a top plate 105a on which the subject P is placed, and under the control of the bed control circuit 106, the top plate 105a is inserted into the cavity (imaging port) of the gradient magnetic field coil 103 with the subject P placed on it. Normally, the bed 105 is set up so that its longitudinal direction is parallel to the central axis of the superconducting magnet 101. Under the control of the computer 130, the bed control circuit 106 drives the bed 105 to move the top plate 105a in the longitudinal and vertical directions.

[0012] The transmitting coil 107 is positioned inside the gradient magnetic field coil 103 and receives RF pulses from the transmitting circuit 108 to generate a high-frequency magnetic field. The transmitting circuit 108 supplies RF pulses to the transmitting coil 107 that correspond to the Larmor frequency, which is determined by the type of atom being targeted and the magnetic field strength.

[0013] The receiving coil 109 is positioned inside the gradient magnetic field coil 103 and receives magnetic resonance signals (hereinafter referred to as "MR signals" as needed) emitted from the subject P due to the influence of the high-frequency magnetic field. When the receiving coil 109 receives a magnetic resonance signal, it outputs the received magnetic resonance signal to the receiving circuit 110.

[0014] The transmitting coil 107 and receiving coil 109 described above are merely examples. The system can be constructed by combining one or more coils, such as a coil with only a transmitting function, a coil with only a receiving function, or a coil with both transmitting and receiving functions.

[0015] The receiving circuit 110 detects the magnetic resonance signal output from the receiving coil 109 and generates magnetic resonance data based on the detected magnetic resonance signal. Specifically, the receiving circuit 110 generates magnetic resonance data by digitally converting the magnetic resonance signal output from the receiving coil 109. The receiving circuit 110 also transmits the generated magnetic resonance data to the sequence control circuit 120. The receiving circuit 110 may be provided on the mounting device side, which includes the superconducting magnet 101 and the gradient magnetic field coil 103. Furthermore, some of the functions of the receiving circuit 110, such as the digital conversion of the magnetic resonance signal, may be provided on the receiving coil 109.

[0016] The sequence control circuit 120 performs imaging of the subject P by driving the gradient power supply 104, the transmitting circuit 108, and the receiving circuit 110 based on sequence information transmitted from the computer 130. Here, the sequence information is information that defines the procedure for performing imaging. The sequence information defines the strength and timing of the current supplied by the gradient power supply 104 to the gradient coil 103, the strength and timing of the RF pulse supplied by the transmitting circuit 108 to the transmitting coil 107, and the timing at which the receiving circuit 110 detects the magnetic resonance signal. For example, the sequence control circuit 120 is an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array), or an electronic circuit such as a CPU (Central Processing Unit) or MPU (Micro Processing Unit). Details of the pulse sequence executed by the sequence control circuit 120 will be described later.

[0017] Furthermore, the sequence control circuit 120 drives the gradient magnetic field power supply 104, the transmitting circuit 108, and the receiving circuit 110 to image the subject P. When it receives magnetic resonance data from the receiving circuit 110, it transfers the received magnetic resonance data to the computer 130.

[0018] Computer 130 performs overall control of the magnetic resonance imaging apparatus 100 and generates images. Computer 130 includes memory 132, input device 134, display 135, and processing circuit 150. Processing circuit 150 includes interface function 131, control function 133, and generation function 136.

[0019] In the first embodiment, each processing function performed by the interface function 131, control function 133, and generation function 136 is stored in memory 132 in the form of a program executable by a computer. The processing circuit 150 is a processor that reads the program from memory 132 and executes it to realize the function corresponding to each program. In other words, the processing circuit 150, in the state where each program has been read, will have the functions shown in the processing circuit 150 of Figure 1. In Figure 1, the processing functions performed by the interface function 131, control function 133, and generation function 136 are realized by a single processing circuit 150, but it is also possible to configure the processing circuit 150 by combining multiple independent processors, and each processor realizes the function by executing a program. In other words, each of the above functions may be configured as a program, and one processing circuit 150 may execute each program. As another example, a specific function may be implemented in a dedicated independent program execution circuit. In Figure 1, the interface function 131, control function 133, and generation function 136 are examples of a receiving unit, a control unit, and a generation unit, respectively. Furthermore, the sequence control circuit 120 is an example of a sequence control unit.

[0020] In the above explanation, the term "processor" refers to circuits such as CPUs (Central Processing Units), GPUs (Graphical Processing Units), Application Specific Integrated Circuits (ASICs), and programmable logic devices (e.g., Simple Programmable Logic Devices (SPLDs), Complex Programmable Logic Devices (CPLDs), and Field Programmable Gate Arrays (FPGAs)). The processor performs its functions by reading and executing programs stored in memory 132.

[0021] Alternatively, instead of saving the program in memory 132, the program may be directly embedded within the processor's circuitry. In this case, the processor performs its functions by reading and executing the program embedded within the circuitry. Similarly, the bed control circuit 106, transmission circuit 108, reception circuit 110, etc., are also configured using the aforementioned processor and other electronic circuits.

[0022] The processing circuit 150 transmits sequence information to the sequence control circuit 120 via the interface function 131 and receives magnetic resonance data from the sequence control circuit 120. Upon receiving the magnetic resonance data, the processing circuit 150, which has the interface function 131, stores the received magnetic resonance data in the memory 132.

[0023] The magnetic resonance data stored in memory 132 is placed in k-space by the control function 133. As a result, memory 132 stores k-space data.

[0024] Memory 132 stores magnetic resonance data received by processing circuit 150 having interface function 131, k-space data arranged in k-space by processing circuit 150 having control function 133, image data generated by processing circuit 150 having generation function 136, and the like. For example, memory 132 is a semiconductor memory element such as RAM (Random Access Memory) or flash memory, a hard disk, or an optical disk.

[0025] The input device 134 receives various instructions and information inputs from the operator. The input device 134 is, for example, a pointing device such as a mouse or trackball, a selection device such as a mode switch, or an input device such as a keyboard. The display 135 displays a GUI (Graphical User Interface) for receiving input of imaging conditions, or images generated by the processing circuit 150 having a generation function 136, under the control of the processing circuit 150 having a control function 133. The display 135 is, for example, a display device such as a liquid crystal display.

[0026] The processing circuit 150, through its control function 133, performs overall control of the magnetic resonance imaging apparatus 100, controlling imaging, image generation, image display, etc. For example, the processing circuit 150 with the control function 133 receives input of imaging conditions (imaging parameters, etc.) via the GUI and generates sequence information according to the received imaging conditions. The processing circuit 150 with the control function 133 also transmits the generated sequence information to the sequence control circuit 120. The processing circuit 150, through its generation function 136, reads k-space data from the memory 132 and generates an image by applying reconstruction processing such as a Fourier transform to the read k-space data.

[0027] Figures 2 to 4 show the structure of the superconducting magnet 101. Figure 2 is an overall view of the structure of the superconducting magnet 101, and Figure 3 is an enlarged view of the area around region 300 in Figure 2. Figure 4 is an example of a cross-sectional view of the superconducting magnet 101.

[0028] As shown in Figure 2, gradient magnetic field coils 103 are arranged inside the cylindrical superconducting magnet 101, and the central space inside the gradient magnetic field coils 103 becomes the imaging space 200. Here, as shown in Figures 3 and 4, the superconducting magnet 101 has superconducting coils 10 (superconducting coils 10A, 10B, 10C, 10D, 10E), a helium tank 11, a thermal shield 12, and a vacuum tank 13.

[0029] The superconducting coil 10 is a coil made of a superconducting material that becomes superconducting under liquid helium. As shown in Figure 3, the superconducting coil 10 consists of multiple superconducting coils. For example, as shown in Figure 3, the superconducting coil 10 consists of multiple superconducting coils such as superconducting coils 10A, 10B, 10C, 10D, and 10E. Here, for example, superconducting coil 10A is the superconducting coil with the highest quench risk among superconducting coils 10A to 10E.

[0030] The helium tank 11 is a helium tank that houses a superconducting coil 10 and holds liquid helium for cooling the superconducting coil 10. The inside of the helium tank 11 is filled with liquid helium to maintain the superconducting state of the superconducting coil 10. The helium tank 11 also has a cooler 14 to maintain the low temperature of the liquid helium.

[0031] Furthermore, a heat shield 12 is provided on the outside of the helium tank 11 to reduce heat intrusion due to radiant heat from outside the superconducting magnet 101, and the heat shield 12 is further covered by a vacuum chamber 13 to provide vacuum insulation inside.

[0032] Having outlined the structure of the superconducting magnet 101, the background of this embodiment will now be explained.

[0033] During scanning by the magnetic resonance imaging apparatus 100, eddy currents are generated primarily in the thermal shield 12 due to pulsed leakage magnetic fields from the gradient magnetic field coils 103. The Lorentz force between these eddy currents and the magnetic field of the superconducting coil 10 can cause the thermal shield 12 to vibrate mechanically. This superimposes new eddy currents within the thermal shield 12, and the resulting eddy magnetic field affects the helium tank 11, causing it to overheat. This mechanism is generally known as the GCIH (Gradient Coil Induced Heating) phenomenon. Specifically, if the GCIJ phenomenon causes eddy magnetic fields generated by mechanical vibrations in the thermal shield 12 due to leakage magnetic fields from the gradient magnetic field coils 103 to overheat the superconducting coil 10 in the helium tank 11, the superconducting coil 10 faces the risk of quenching and subsequent destruction of its superconducting state. As an example, in Figure 3, among the superconducting coils 10, superconducting coil 10A corresponds to the largest magnetic field, and therefore has a high risk of quenching.

[0034] To reduce the quench risk of the superconducting coil 10, methods such as lowering the leakage magnetic field of the gradient coil 103, suppressing the mechanical vibration of the thermal shield 12, increasing the quench margin of the superconducting coil 10, and controlling the pulse sequence executed by the sequence control circuit 120 can be considered. However, if higher image quality is required, for example, it is necessary to increase the output of the gradient coil 103, so it is desirable that additional measures be taken.

[0035] The embodiment is based on the above background, and the superconducting magnet 101 according to the embodiment comprises, for example, a helium tank 11 for holding liquid helium to cool the superconducting coil 10A (superconducting coil 10), and a heat conductive material 1, as shown in Figure 5. The heat conductive material 1 extends from the outer circumferential surface of the helium tank 11, from a first portion 3 corresponding to the part of the helium tank 11 where the superconducting coil 10A is located, to a second portion 4 corresponding to the outer circumferential surface of the helium tank 11 where the superconducting coil 10 is not located. Furthermore, an insulating material 2 is placed between the part of the helium tank 11 corresponding to the part where the superconducting coil is located and the heat conductive material 1.

[0036] As the thermal conductive material 1, a high thermal conductive material such as high-purity aluminum is used. That is, the thermal conductive material 1 may be a material containing aluminum. Since high thermal conductive materials are generally also high electrical conductive materials, the thermal conductive material 1 is also a high electrical conductive material. Furthermore, the thermal conductive material 1 is placed inside the heat shield 12.

[0037] With this configuration, the presence of the heat conductive material 1 allows the heat generated by the GCIH phenomenon to be actively generated within the heat conductive material 1, thereby reducing the heat generated within the helium tank 11. Furthermore, the presence of the insulating material 2 prevents the heat generated within the heat conductive material 1 from being transferred to the superconducting coil 10A, thereby reducing the risk of the superconducting coil 10A quenching. In addition, since the heat conductive material 1 extends from the outer circumferential surface of the helium tank 11, specifically from a first portion 3 corresponding to the part of the helium tank 11 where the superconducting coil 10A is located, to a second portion 4 corresponding to the outer circumferential surface of the helium tank 11 where the superconducting coil 10 is not located, heat generated in the first portion 3 can be discharged through the second portion 4, for example, thereby reducing the risk of quenching.

[0038] (Modifications of the First Embodiment) The embodiments are not limited to the examples described above. In the above embodiments, the case in which high-purity aluminum material is used as the heat conductive material 1 was described, but other materials may be used as the heat conductive material 1. For example, the heat conductive material 1 may be high-purity copper. That is, the heat conductive material 1 may be a material containing copper.

[0039] Furthermore, the embodiments are not limited to the examples described above. For example, in one embodiment, the second portion 4 of the heat conductive material 1 may be in contact with the helium tank 11. That is, the heat conductive material 1 may have a contact portion 5 that is in contact with the helium tank 11 at a location away from the superconducting coil 10. For example, the second portion 4 on the outer circumferential surface of the helium tank 11, corresponding to the portion of the helium tank 11 where the superconducting coil 10A is not located, may be welded to the helium tank 11. Another example is that the second portion 4 may be in contact with the helium tank 11 via vacuum grease with high thermal conductivity. Another example is that the second portion 4 may be in contact with the helium tank 11 via a soft metal such as a metal containing indium. In this way, by the heat conductive material 1 being in contact with the helium tank 11 at the second portion 4 corresponding to the portion where the superconducting coil 10A is not located, the heat generated in the heat conductive material 1 can be efficiently discharged, and the quench risk of the superconducting coil 10A can be reduced.

[0040] In this embodiment, the heat conductive material 1 does not need to be in contact with the helium tank 11. In this case, heat is less likely to be released into the helium tank 11, thus reducing the amount of liquid helium consumed. On the other hand, in this case, the temperature of the heat conductive material 1 itself will be higher than the liquid helium temperature, so the conductivity of the heat conductive material 1 will decrease, and the shielding effect of the eddy magnetic field will be slightly reduced.

[0041] Furthermore, in this embodiment, the superconducting magnet 101 may have the thermal conductive material 1 placed in locations corresponding to all parts of the superconducting coils 10A to 10E, or it may have the thermal conductive material 1 placed only in the parts corresponding to specific superconducting coils. For example, the thermal conductive material 1 may extend from the outer surface of the helium tank 11, from a first portion 3 corresponding to the part of the helium tank 11 where the superconducting coil 10A with the highest quench risk is located, to a second portion 4 corresponding to the part where no superconducting coils 10 are located.

[0042] Also, in the example of FIG. 5, the case where the heat conductive material 1 is extended from the first portion 3 to the second portion 4 in the radial direction of the superconducting magnet 101 (that is, the vertical direction of the drawing in FIG. 5) has been described. However, the embodiment is not limited to this. In the embodiment, the heat conductive material 1 may be extended in the axial direction of the superconducting magnet 101 (that is, the left - right direction of the drawing in FIG. 5).

[0043] (Second Embodiment) In the first embodiment, the case where the superconducting coil is cooled using liquid helium with the helium tank 11 has been described. However, the embodiment is not limited to this. In the second embodiment, the case where the magnetic resonance imaging apparatus 100 is so - called helium - free, that is, the case where the cooling of the superconducting magnet 101 is performed in a helium - free manner, will be described.

[0044] FIG. 6 shows an example of the configuration when the superconducting magnet 101 is helium - free. The structure outside the heat shield 12 of the superconducting magnet 101 is the same as that in the first embodiment. Here, when the superconducting magnet 101 is helium - free, the helium tank 11 does not exist. Instead, as shown in FIG. 6, the superconducting magnet 101 has a bobbin 20 (winding frame) that holds the superconducting coil 10, and the bobbin 20 that holds the superconducting coil 10 is supported by a member 40 extending from the heat shield 12. Different from the first embodiment having the helium tank 11, the superconducting coil 10 is directly connected to the cooler 14 by a conductor 30 such as a metal.

[0045] Here, as shown in FIG. 6, the superconducting magnet 101 according to the second embodiment includes a bobbin 20 that holds the superconducting coil 10, and a heat conductive material 1 that extends from a first portion on the outer peripheral surface of the bobbin 20 corresponding to the portion where the superconducting coil 10 is disposed in the bobbin 20 to a second portion on the outer peripheral surface of the bobbin 20 corresponding to the portion where the superconducting coil 10 is not disposed in the bobbin 20. Also, the heat conductive material 1 is connected to a heat conductive material 41 connected to the member 40 that supports the bobbin 20. Further, a heat insulating material 2 is disposed between the portion corresponding to the portion where the superconducting coil 10 is disposed in the bobbin 20 and the heat conductive material 1.

[0046] As the heat conduction material 1, a high heat conduction material such as a high purity aluminum material is used. That is, the heat conduction material 1 may be a material containing aluminum. Since a high heat conduction material is generally also a high electrical conduction material, the heat conduction material 1 is also a high electrical conduction material. Further, the heat conduction material 1 is disposed inside the heat shield 12.

[0047] According to such a configuration, similar to the first embodiment, in the second embodiment, due to the presence of the heat conduction material 1, heat generation due to the GCIH phenomenon can be actively generated within the heat conduction material 1, and as a result, heat generation of the superconducting coil 10 can be reduced. Further, due to the presence of the heat insulating material 2, heat generated within the heat conduction material 1 can be prevented from being transmitted to the superconducting coil 10, and the risk of the superconducting coil 10 quenching can be reduced. Further, the heat conduction material 1 extends from a first portion on the outer peripheral surface of the bobbin 20 corresponding to the portion of the bobbin 20 where the superconducting coil 10 is disposed to a second portion on the outer peripheral surface of the bobbin 20 corresponding to the portion of the bobbin 20 where the superconducting coil 10 is not disposed. Therefore, for example, heat generated in the first portion can be discharged through the second portion, so that the quenching risk can be reduced.

[0048] Further, the form of the bobbin 20 in the embodiment is not limited to the above example. For example, as shown in FIG. 7, a bobbin that holds each of the superconducting coils constituting the superconducting coil 10 may have the superconducting magnet 101 according to the second embodiment. The bobbin 20a shown in FIG. 7 is an example of such a bobbin.

[0049] Note that the embodiment is not limited to the above example. As an example, the heat conduction material 1 may be, for example, high purity copper. Further, the second portion of the heat conduction material may contact the bobbin 20. As an example, the second portion may be welded to the bobbin 20. As another example, the second portion may contact the bobbin 20 through a vacuum grease having high heat conductivity. As another example, the second portion may contact the bobbin 20 through a soft metal such as a metal containing indium.

[0050] According to at least one embodiment described above, the quench risk of superconducting magnets can be reduced.

[0051] While several embodiments have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be implemented in a variety of other forms, and various omissions, substitutions, modifications, and combinations of embodiments are possible without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents.

[0052] 1. Thermal conductive material 2. Insulating material 3. First part 4. Second part 5. Contact part 10A. Superconducting coil 10B. Superconducting coil 10C. Superconducting coil 10D. Superconducting coil 10E. Superconducting coil 10. Superconducting coil 11. Helium tank 12. Thermal shield 13. Vacuum tank 20. Bobbin 30. Conductor 40. Component 41. Thermal conductive material 101. Superconducting magnet 103. Gradient magnetic field coil

Claims

1. A superconducting magnet comprising: a bobbin for holding a superconducting coil; and a thermal conductive material extending from a first portion of the outer circumferential surface of the bobbin, corresponding to the portion of the bobbin where the superconducting coil is located, to a second portion of the outer circumferential surface of the bobbin, corresponding to the portion of the bobbin where the superconducting coil is not located.

2. A superconducting magnet comprising: a helium tank for holding liquid helium for cooling a superconducting coil; and a thermal conductive material extending from a first portion of the outer circumferential surface of the helium tank, corresponding to the portion of the helium tank in which the superconducting coil is located, to a second portion of the outer circumferential surface of the helium tank, corresponding to the portion of the helium tank in which the superconducting coil is not located.

3. The superconducting magnet according to claim 1, wherein the cooling of the superconducting magnet is performed in a helium-free manner.

4. The superconducting magnet according to claim 1, wherein the heat conductive material is connected to a member supporting the bobbin.

5. An insulating material is placed between the portion of the bobbin corresponding to the portion in which the superconducting coil is arranged and the heat conductive material. The superconducting magnet according to claim 1.

6. An insulating material is placed between the portion of the helium tank corresponding to the portion where the superconducting coil is located and the heat conductive material. The superconducting magnet according to claim 2.

7. The superconducting magnet according to claim 1 or 2, wherein the thermal conductive material is a material containing aluminum.

8. The superconducting magnet according to claim 1 or 2, wherein the heat conductive material is a material containing copper.

9. The superconducting magnet according to claim 2, wherein the second portion of the heat conductive material is in contact with the helium tank.

10. The superconducting magnet according to claim 9, wherein the second portion is welded to the helium tank.

11. The superconducting magnet according to claim 9, wherein the second portion is in contact with the helium tank via vacuum grease.

12. The superconducting magnet according to claim 9, wherein the second portion is in contact with the helium tank via a metal.

13. The superconducting magnet according to claim 12, wherein the metal is an indium-containing metal.

14. The superconducting magnet according to claim 1 or 2, wherein the heat conductive material is disposed inside the heat shield.

15. The superconducting magnet according to claim 2, wherein the first portion is the outer surface of the helium tank and corresponds to the portion where the superconducting coil with the highest quench risk is located.

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