Superconducting magnet device and magnetic resonance imaging device

Abstract

To efficiently cool multiple structures while reducing the amount of refrigerant used. [Solution] The superconducting magnet device according to the embodiment comprises a superconducting coil, a structure, a refrigerant tank, a heat exchanger, a refrigerator, a solid heat conductor, and a vacuum vessel. The superconducting coil is composed of a superconducting wire that forms a magnetic field. The structure is composed of a superconductor and is electrically connected to the superconducting coil. The refrigerant tank stores a refrigerant. The heat exchanger is exposed inside the refrigerant tank. The refrigerator cools the refrigerant. The solid heat conductor directly or indirectly thermally connects the refrigerant tank, the superconducting coil, and the structure. The superconducting coil or the structure is composed of at least two structures with different operating temperatures or superconducting properties as superconductors.

Description

Technical Field

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

Background Art

[0002] Conventionally, as a static magnetic field magnet that generates a static magnetic field in an imaging space where a subject is placed, a magnetic resonance imaging (MRI) device including a superconducting magnet device is known.

[0003] Generally, a superconducting magnet device provided in an MRI device includes a cooling container filled with a refrigerant such as liquid helium, a refrigerator that cools the refrigerant in the cooling container, and a superconducting coil immersed in the refrigerant in the cooling container. Here, the superconducting coil is composed of superconducting wire, and is energized in a state where it is cooled by the refrigerant and transitions to a superconducting state, thereby generating a magnetic field.

[0004] In recent years, in such a superconducting magnet device, it has been required to efficiently cool a plurality of structures to be cooled while reducing the amount of the refrigerant.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] One of the problems that the embodiments disclosed herein and in the drawings aim to solve is to efficiently cool multiple structures to be cooled while reducing the amount of refrigerant used. However, the problems that the embodiments disclosed herein and in the drawings aim to solve are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described later can also be positioned as other problems. [Means for solving the problem]

[0007] The superconducting magnet device according to this embodiment comprises a superconducting coil, a structure, a refrigerant tank, a heat exchanger, a refrigerator, a solid heat conductor, and a vacuum vessel. The superconducting coil is composed of a superconducting wire that forms a magnetic field. The structure is composed of a superconductor and is electrically connected to the superconducting coil. The refrigerant tank stores a refrigerant. The heat exchanger is exposed inside the refrigerant tank. The refrigerator cools the refrigerant. The solid heat conductor directly or indirectly thermally connects the refrigerant tank, the superconducting coil, and the structure. The vacuum vessel encloses the superconducting coil, the structure, the refrigerant tank, the heat exchanger, the refrigerator, and the solid heat conductor. The superconducting coil or the structure is composed of at least two structures with different operating temperatures or superconducting properties as superconductors. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 shows an example of the configuration of an MRI apparatus according to the first embodiment. [Figure 2] Figure 2 shows an example of a superconducting magnet device according to a comparative example of the first embodiment. [Figure 3] Figure 3 shows an example of a superconducting magnet device according to the first embodiment. [Figure 4] Figure 4 shows a modified example of the superconducting magnet device according to the first embodiment. [Figure 5] Figure 5 shows an example of a superconducting magnet device according to the second embodiment. [Figure 6]Figure 6 shows an example of a superconducting magnet device according to the third embodiment. [Figure 7] Figure 7 shows an example of a superconducting magnet device according to the fourth embodiment. [Figure 8] Figure 8 shows an example of a superconducting magnet device according to the fifth embodiment. [Figure 9] Figure 9 shows an example of a superconducting magnet device according to the sixth embodiment. [Figure 10] Figure 10 shows an example of a superconducting magnet device according to the seventh embodiment. [Figure 11] Figure 11 shows an example of a superconducting magnet device according to the eighth embodiment. [Modes for carrying out the invention]

[0009] Hereinafter, embodiments of the superconducting magnet apparatus and MRI apparatus according to the present application will be described in detail with reference to the drawings.

[0010] (First Embodiment) Figure 1 shows an example of the configuration of an MRI apparatus according to the first embodiment.

[0011] For example, as shown in Figure 1, the MRI apparatus 100 includes a static magnetic field magnet 1, gradient magnetic field coils 2, gradient magnetic field power supply 3, whole-body radio frequency (RF) coil 4, local RF coil 5, transmitting circuit 6, receiving circuit 7, RF shield 8, gantry 9, patient table 10, input interface 11, display 12, memory circuit 13, and processing circuits 14-17.

[0012] The static magnetic field magnet 1 generates a static magnetic field in the imaging space where the subject S is placed. Specifically, the static magnetic field magnet 1 is formed in a hollow, substantially cylindrical shape (including those with an elliptical cross-sectional shape perpendicular to the central axis), and generates a static magnetic field in the imaging space formed on its inner circumference.

[0013] The gradient magnetic field coil 2 is disposed inside the static magnetic field magnet 1 and generates a gradient magnetic field in the imaging space where the subject S is disposed. Specifically, the gradient magnetic field coil 2 is formed in a hollow substantially cylindrical shape (including those having an elliptical shape in a cross section orthogonal to the central axis), and has an X coil, a Y coil, and a Z coil corresponding to the X-axis, the Y-axis, and the Z-axis orthogonal to each other, respectively. The X coil, the Y coil, and the Z coil generate a gradient magnetic field that linearly changes along each axial direction in the imaging space based on the current supplied from the gradient magnetic field power supply 3. Here, the Z-axis is set to be along the magnetic flux of the static magnetic field generated by the static magnetic field magnet 1. Also, the X-axis is set to be along the horizontal direction orthogonal to the Z-axis, and the Y-axis is set to be along the vertical direction orthogonal to the Z-axis. Here, the X-axis, the Y-axis, and the Z-axis constitute a device coordinate system unique to the MRI apparatus 100.

[0014] The gradient magnetic field power supply 3 generates a gradient magnetic field in the imaging space by supplying current to the gradient magnetic field coil 2. Specifically, the gradient magnetic field power supply 3 supplies current individually to the X coil, the Y coil, and the Z coil of the gradient magnetic field coil 2, thereby generating a gradient magnetic field that linearly changes along the readout direction, the phase encoding direction, and the slice direction orthogonal to each other in the imaging space. Here, the axis along the readout direction, the axis along the phase encoding direction, and the axis along the slice direction constitute a logical coordinate system for defining the slice region or volume region to be imaged.

[0015] The gradient magnetic fields along the readout direction, the phase encoding direction, and the slice direction are superimposed on the static magnetic field generated by the static magnetic field magnet 1, thereby imparting spatial position information to the nuclear magnetic resonance (NMR) signal generated from the subject S. Specifically, the gradient magnetic field in the readout direction imparts the position information in the readout direction to the NMR signal by changing the frequency of the NMR signal according to the position in the readout direction. Further, the gradient magnetic field in the phase encoding direction imparts the position information in the phase encoding direction to the NMR signal by changing the phase of the NMR signal according to the position in the phase encoding direction. Further, when two-dimensional MR images (slice images) are acquired, the gradient magnetic field in the slice direction determines the position, thickness, and number of slices to be acquired by changing the frequency of the NMR signal according to the position in the slice direction. Further, when three-dimensional MR images (volume images) are acquired, the gradient magnetic field in the slice direction imparts the position information in the slice direction to the NMR signal by changing the phase of the NMR signal according to the position in the slice direction.

[0016] The whole-body RF coil 4 is disposed on the inner peripheral side of the gradient magnetic field coil 2, applies an RF pulse (excitation pulse or the like) to the subject S disposed in the imaging space, and receives the NMR signal (echo signal or the like) generated from the subject S due to the influence of the RF pulse. Specifically, the whole-body RF coil 4 is formed in a hollow substantially cylindrical shape (including those having an elliptical shape in the cross-section perpendicular to the central axis), and applies an RF pulse to the subject S disposed in the imaging space located on its inner peripheral side based on the RF pulse signal supplied from the transmission circuit 6. Then, the whole-body RF coil 4 receives the NMR signal generated from the subject S due to the influence of the RF pulse, and outputs the received NMR signal to the reception circuit 7. For example, the whole-body RF coil 4 is a birdcage type coil or a TEM (Transverse Electromagnetic) coil.

[0017] The local RF coil 5 is positioned near the subject S during imaging and receives the NMR signal generated from the subject S. Specifically, a local RF coil 5 is provided for each part of the subject S, and is positioned near the area to be imaged when imaging of the subject S is performed. It receives the NMR signal generated from the subject S due to the influence of the RF pulse applied by the whole-body RF coil 4, and outputs the received NMR signal to the receiving circuit 7. For example, the local RF coil 5 is a surface coil or a phased array coil composed of multiple surface coils combined as coil elements. The local RF coil 5 may also have a transmission function to apply RF pulses to the subject.

[0018] The transmitting circuit 6 outputs an RF pulse signal corresponding to the resonance frequency (Larmor frequency) unique to the target atomic nucleus placed in the static magnetic field to the whole-body RF coil 4 or the local RF coil 5. Specifically, the transmitting circuit 6 has a pulse generator, an RF generator, a modulator, and an amplifier. The pulse generator generates the waveform of the RF pulse signal. The RF generator generates an RF signal at the resonance frequency. The modulator generates an RF pulse signal by modulating the amplitude of the RF signal generated by the RF generator with the waveform generated by the pulse generator. The amplifier amplifies the RF pulse signal generated by the modulator and outputs it to the whole-body RF coil 4 or the local RF coil 5.

[0019] The receiving circuit 7 generates NMR data based on the NMR signal output from the whole-body RF coil 4 or the local RF coil 5, and outputs the generated NMR data to the processing circuit 15. Specifically, the receiving circuit 7 includes a selector, a preamplifier, a phase detector, and an A / D (analog / digital) converter. The selector selectively inputs the NMR signal output from the whole-body RF coil 4 or the local RF coil 5. The preamplifier amplifies the NMR signal output from the selector. The phase detector detects the phase of the NMR signal output from the preamplifier. The A / D converter generates NMR data by converting the analog signal output from the phase detector into a digital signal, and outputs the generated NMR data to the processing circuit 15. Note that, as described here, each process performed by the receiving circuit 7 does not necessarily have to be performed entirely by the receiving circuit 7; some processing (for example, processing by the A / D converter) may be performed by the whole-body RF coil 4 or the local RF coil 5.

[0020] The RF shield 8 is positioned between the gradient magnetic field coil 2 and the whole-body RF coil 4, shielding the gradient magnetic field coil 2 from RF pulses generated by the whole-body RF coil 4. Specifically, the RF shield 8 is formed in a hollow, substantially cylindrical shape (including those with an elliptical cross-section perpendicular to the central axis of the cylinder), and is positioned in the space on the inner circumference side of the gradient magnetic field coil 2 so as to cover the outer surface of the whole-body RF coil 4.

[0021] The rig 9 has a hollow bore 9a formed in a substantially cylindrical shape (including those with an elliptical cross-sectional shape perpendicular to the central axis), and houses a static magnetic field magnet 1, a gradient magnetic field coil 2, a whole-body RF coil 4, and an RF shield 8. Specifically, the rig 9 houses the whole-body RF coil 4 on the outer circumference of the bore 9a, the RF shield 8 on the outer circumference of the whole-body RF coil 4, the gradient magnetic field coil 2 on the outer circumference of the RF shield 8, and the static magnetic field magnet 1 on the outer circumference of the gradient magnetic field coil 2. Here, the space within the bore 9a of the rig 9 becomes the imaging space where the subject S is placed during imaging.

[0022] The examination bed 10 is equipped with a top plate 10a on which the subject S is placed, and when imaging of the subject S is performed, the top plate 10a on which the subject S is placed is moved into the imaging space. For example, the examination bed 10 is installed so that the longitudinal direction of the top plate 10a is parallel to the central axis of the static magnetic field magnet 1.

[0023] The input interface 11 receives various instructions and information input operations from the operator. Specifically, the input interface 11 is connected to the processing circuit 17 and converts the input operations received from the operator into electrical signals and outputs them to the processing circuit 17. For example, the input interface 11 can be implemented by a trackball for setting imaging conditions and regions of interest (ROI), a switch button, a mouse, a keyboard, a touchpad for input operations by touching the operating surface, a touchscreen that integrates a display screen and a touchpad, a non-contact input circuit using an optical sensor, and an audio input circuit. In this specification, the input interface 11 is not limited to those equipped with physical operating components such as a mouse or keyboard. For example, an electrical signal processing circuit that receives electrical signals corresponding to input operations from an external input device provided separately from the device and outputs these electrical signals to a control circuit is also included as an example of the input interface 11.

[0024] The display 12 displays various types of information. Specifically, the display 12 is connected to the processing circuit 17 and converts the data of various types of information sent from the processing circuit 17 into electrical signals for display and outputs them. For example, the display 12 can be implemented as an LCD monitor, a CRT (Cathode Ray Tube) monitor, a touch panel, etc.

[0025] The memory circuit 13 stores various types of data. Specifically, the memory circuit 13 is connected to processing circuits 14-17 and stores various types of data input and output by each processing circuit. For example, the memory circuit 13 can be implemented using semiconductor memory elements such as RAM (Random Access Memory) or flash memory, or a hard disk or optical disc.

[0026] The processing circuit 14 has a bed control function 14a. The bed control function 14a controls the operation of the bed 10 by outputting control electrical signals to the bed 10. For example, the bed control function 14a receives instructions from the operator via the input interface 11 to move the top plate 10a in the longitudinal direction, vertical direction, or horizontal direction, and operates the bed 10's top plate 10a movement mechanism to move the top plate 10a according to the received instructions.

[0027] The processing circuit 15 has an acquisition function 15a. The acquisition function 15a acquires NMR data of the subject S by executing various pulse sequences. Specifically, the acquisition function 15a executes various pulse sequences by driving the gradient power supply 3, the transmitting circuit 6, and the receiving circuit 7 according to the sequence execution data output from the processing circuit 17. Here, the sequence execution data is data representing the pulse sequence and is information that defines the timing and strength of the current supplied by the gradient power supply 3 to the gradient coil 2, the timing and strength of the RF pulse signal supplied by the transmitting circuit 6 to the whole-body RF coil 4, and the timing of the NMR signal sampling by the receiving circuit 7. The acquisition function 15a then receives the NMR data output from the receiving circuit 7 as a result of executing the pulse sequence and stores it in the memory circuit 13. At this time, the NMR data stored in the memory circuit 13 is stored as k-space data representing a two-dimensional or three-dimensional k-space, with position information along the readout direction, phase encoding direction, and slice direction assigned by each of the aforementioned gradient magnetic fields.

[0028] The processing circuit 16 has a generation function 16a. The generation function 16a generates an MR image from the NMR data collected by the collection function 15a of the processing circuit 15. Specifically, under the control of the processing circuit 17, the generation function 16a reads the NMR data collected by the collection function 15a of the processing circuit 15 from the storage circuit 13, and generates a two-dimensional or three-dimensional MR image by applying reconstruction processing such as a Fourier transform to the read-out NMR data. Then, the generation function 16a stores the generated MR image in the storage circuit 13.

[0029] The processing circuit 17 has an imaging control function 17a. The imaging control function 17a controls the MRI device 100 as a whole by controlling each component of the MRI device 100. Specifically, the imaging control function 17a displays a GUI (Graphical User Interface) on the display 12 to receive various instructions and information input operations from the operator, and controls each component of the MRI device 100 in accordance with the input operations received via the input interface 11. For example, the imaging control function 17a receives input of imaging conditions from the operator and sets a pulse sequence for collecting NMR data of the subject S based on the input imaging conditions. The imaging control function 17a then generates sequence execution data representing the set pulse sequence and outputs it to the processing circuit 15, causing the collection function 15a of the processing circuit 15 to execute various pulse sequences. Also, for example, the imaging control function 17a controls the generation function 16a of the processing circuit 16 to reconstruct an MR image from the k-space data collected by the processing circuit 15. Furthermore, for example, the imaging control function 17a reads out the MR image stored in the memory circuit 13 in response to a request from the operator and displays the read-out MR image on the display 12.

[0030] Here, the processing circuits 14 to 17 described above are implemented, for example, by a processor. In this case, the processing functions of each processing circuit are stored in the memory circuit 13 in the form of a program that can be executed by a computer. Then, each processing circuit reads each program from the memory circuit 13 and executes it, thereby realizing the processing function corresponding to each program. In other words, each processing circuit, with each program read, will have the processing functions shown in Figure 1.

[0031] In this description, processing circuits 14 to 17 are assumed to be implemented by a single processor, but the embodiments are not limited to this. For example, each processing circuit may be composed of a combination of multiple independent processors, with each processor executing a program to realize each processing function. Furthermore, the processing functions of each processing circuit may be appropriately distributed or integrated across one or more processing circuits. Also, in the above description, a single memory circuit 13 is assumed to store the program corresponding to each processing function, but the embodiments are not limited to this. For example, multiple memory circuits may be distributed among the processing circuits, and each processing circuit may read the corresponding program from its individual memory circuit.

[0032] The configuration example of the MRI apparatus 100 according to this embodiment has been described above. Under this configuration, the MRI apparatus 100 according to this embodiment is equipped with a superconducting magnet device as a static magnetic field magnet 1 that generates a static magnetic field in the imaging space where the subject S is placed.

[0033] Figure 2 shows an example of a superconducting magnet device according to a comparative example of the first embodiment.

[0034] For example, as shown in Figure 2, a superconducting magnet device typically found in an MRI machine includes a cooling container filled with a refrigerant such as liquid helium, a refrigerator for cooling the refrigerant in the cooling container, and a superconducting coil immersed in the refrigerant in the cooling container. Here, the superconducting coil is made of superconducting wire and generates a magnetic field when it is cooled by the refrigerant, transitions to a superconducting state, and is then energized.

[0035] In recent years, such superconducting magnet devices have required efficient cooling of multiple structures while reducing the amount of refrigerant used.

[0036] Therefore, in the MRI apparatus 100 according to this embodiment, the superconducting magnet device provided as the static magnetic field magnet 1 is configured to efficiently cool multiple structures to be cooled while reducing the amount of refrigerant. The superconducting magnet device provided as the static magnetic field magnet 1 in the MRI apparatus 100 according to this embodiment will be described in detail below.

[0037] Figure 3 shows an example of a superconducting magnet device 200 according to the first embodiment.

[0038] For example, as shown in Figure 3, the superconducting magnet device 200 according to this embodiment includes a superconducting coil 201, structures 202 and 203, a refrigerant tank 204, a heat exchanger 205, a refrigerator 206, a radiation shield 207, a thermal anchor 208, a pre-cooling pipe 209, a refrigerant tank 210, piping 211, solid heat conductors 212 to 215, a heat capacity holder 216, a vacuum container 217, and a lid 218.

[0039] The superconducting coil 201 is composed of superconducting wires that form a magnetic field. Specifically, the superconducting coil 201 is composed of low-temperature superconductor (LTS) wires.

[0040] Structures 202 and 203 are each made of superconductors and are electrically connected to the superconducting coil 201. For example, structure 202 is a Persistent Current Switch (PCS). A PCS is made by winding a superconducting wire without induction and is a switch that can disconnect the superconducting coil circuit when it transitions to a normal conducting state. Also, for example, structure 203 is superconducting solder. Superconducting solder is used to join superconducting wires and becomes superconducting when cooled.

[0041] Here, the superconducting coil 201, structure 202, and structure 203 each have different operating temperatures or superconducting properties. The operating temperature is a temperature lower than the critical temperature and is set as the temperature at which operation in a superconducting state is possible. The superconducting properties are the critical temperature (Tc), critical magnetic field (Bc), or critical current (Ic). The critical temperature (Tc) is the temperature at which the transition occurs from the superconducting state to the normal conducting state, the critical magnetic field (Bc) is the magnetic field at which the transition occurs from the superconducting state to the normal conducting state, and the critical current (Ic) is the current at which the transition occurs from the superconducting state to the normal conducting state.

[0042] Furthermore, the superconducting coil 201, structure 202, and structure 203 are each constructed using low-temperature superconductor (LTS) material, high-temperature superconductor (HTS) material, protective material, matrix material, and substrate, respectively, which have different thermal conductivity or specific heat properties. The LTS material is, for example, a metal such as NbTi or Nb3Sn. The HTS material is, for example, a metal such as REBCO, MgB2, or Bi. The protective agent, matrix material, and substrate are, for example, metals such as Cu, CuNi, Al, or Ag.

[0043] Furthermore, in this embodiment, the superconducting coil 201, structure 202, and structure 203 are configured such that the heat capacity of structure 202 is smaller than that of the superconducting coil 201, and the heat capacity of structure 203 is smaller than that of structure 202.

[0044] The refrigerant tank 204 stores a refrigerant such as liquid helium.

[0045] The heat exchanger 205 is exposed inside the refrigerant tank 204 and reliquefies the vaporized refrigerant and returns it to the refrigerant tank 204.

[0046] The refrigerator 206 cools the refrigerant in the refrigerant tank 204. Specifically, the refrigerator 206 has a high-temperature end 206a that is at a first temperature (e.g., 50K) and a low-temperature end 206b that is at a second temperature lower than the first temperature (e.g., 4K), and the refrigerant in the refrigerant tank 204 is cooled to the second temperature at the low-temperature end 206b.

[0047] The radiant shield 207 is positioned between the vacuum vessel 217 and the multiple structures to be cooled housed within the vacuum vessel 217, reducing heat intrusion into each structure. Specifically, the radiant shield 207 is made of a metal such as aluminum or copper, and is thermally connected to the high-temperature end 206a of the refrigerator 206 to maintain a first temperature, thereby reducing heat intrusion from the vacuum vessel 217, which is at ambient temperature, into each structure. Note that only a portion of the radiant shield 207 is shown in Figure 3.

[0048] The thermal anchor 208 reduces heat intrusion through the pre-cooling pipe 209 by thermally connecting the radiant shield 207 and the pre-cooling pipe 209.

[0049] The pre-cooling tube 209 is positioned to be in thermal contact with the outer circumference of the superconducting coil 201, and the superconducting coil 201 is pre-cooled by the circulation of cooling gas through an inlet and outlet exposed to the outside of the vacuum vessel 217. Specifically, the pre-cooling tube 209 is made of a metal with low thermal conductivity (e.g., phosphorus-deoxidized copper) from the inlet and outlet to the point where the thermal anchor 208 is connected, and the part of the pre-cooling tube 209 that is in contact with the outer circumference of the superconducting coil 201, as well as the part that is the outer circumference of the superconducting coil 201, is made of a metal with high thermal conductivity.

[0050] The refrigerant tank 210 stores the refrigerant transported from the refrigerant tank 204, seals the structure 202 in the refrigerant while it is immersed in it, and cools the structure 202 to a second temperature.

[0051] The piping 211 is installed between the refrigerant tank 204 and the refrigerant tank 210, and transports refrigerant from the refrigerant tank 204 to the structure 202 inside the refrigerant tank 210.

[0052] Here, the piping 211 has at least two parameters set from among dimensions, thermal conductivity, and thermal load, depending on the operating temperature or superconducting properties of the structure 202.

[0053] The solid thermal conductors 212-215 are made of metals with high thermal conductivity (for example, pure aluminum or copper), and directly or indirectly thermally connect the refrigerant tank 204 to the superconducting coil 201, and the refrigerant tank 204 to the structure 203.

[0054] For example, the solid heat conductors 212 to 215 are made of metals with high thermal conductivity formed in the form of plates, squares, tapes, or sheets, or of metals formed in the form of cylindrical pipes with a set thermal conductivity depending on the structure they are in thermal contact with. Of these, the metals formed in the form of tapes are preferable to the other materials because they are readily available and easy to manufacture.

[0055] Specifically, the solid heat conductor 212 has one end in thermal contact with the refrigerant tank 204 and the other end in thermal contact with a point on the outer circumference of the superconducting coil 201. By propagating the temperature of the refrigerant in the refrigerant tank 204 to the superconducting coil 201, the superconducting coil 201 is cooled to a second temperature.

[0056] Furthermore, the solid heat conductors 213 and 214 each have one end that is thermally in contact with the refrigerant tank 204, and the other end that is thermally in contact with a point within the range from the point where the thermal anchor 208 of the pre-cooling pipe 209 is connected to the point where it contacts the outer circumference of the superconducting coil 201. By transmitting the temperature of the refrigerant in the refrigerant tank 204 to the superconducting coil 201 via the pre-cooling pipe 209, the superconducting coil 201 is cooled to a second temperature.

[0057] Furthermore, the solid heat conductor 215 has one end in thermal contact with a point on the pipe 211 and the other end in contact with the structure 203, and cools the structure 203 to a second temperature by transmitting the temperature of the refrigerant in the refrigerant tank 204 to the structure 203 via the pipe 211.

[0058] Here, each of the solid heat conductors 212 to 214 has at least two parameters set from among dimensions, thermal conductivity, and thermal load, depending on the operating temperature or superconducting properties of the superconducting coil 201. Similarly, each of the solid heat conductors 215 has at least two parameters set from among dimensions, thermal conductivity, and thermal load, depending on the operating temperature or superconducting properties of the structure 203.

[0059] The heat capacity holder 216 is made of a metal having a predetermined heat capacity (for example, SUS, etc.) and is attached to the solid heat conductor 212 to hold the heat capacity of the solid heat conductor 212.

[0060] Here, the heat capacity holder 216 has at least two parameters set from among dimensions, thermal conductivity, and thermal load, depending on the operating temperature or superconducting properties of the superconducting coil 201 which is cooled by the solid heat conductor 212.

[0061] The vacuum vessel 217 encloses the superconducting coil 201, structure 202, structure 203, refrigerant tank 204, heat exchanger 205, radiation shield 207, thermal anchor 208, pre-cooling pipe 209, refrigerant tank 210, piping 211, solid heat conductors 212-215, and heat capacity holder 216.

[0062] The lid 218 is attached to the vacuum container 217 so as to cover the inlet and outlet of the pre-cooling tube 209, and by creating a vacuum inside, the pre-cooling tube 209 is kept in a vacuum state.

[0063] With the above-described configuration, compared to immersion-type superconducting magnet devices in which superconducting coils are submerged in a coolant in a cooling container, the superconducting coils can be cooled with a small coolant tank, thus reducing the amount of coolant required. Furthermore, by individually cooling multiple structures to be cooled using solid heat conductors and piping, it becomes possible to efficiently cool each structure, which may have different operating temperatures or superconducting properties.

[0064] Therefore, according to the first embodiment, multiple structures to be cooled can be efficiently cooled while reducing the amount of refrigerant.

[0065] Furthermore, the above-described configuration makes it possible to reduce the amount of refrigerant compared to immersion-type superconducting magnet devices, thereby enabling a lighter superconducting magnet device.

[0066] Furthermore, with the above-described configuration, by attaching the heat capacity holder 216 to the solid heat conductor 212, even if the refrigerator 206 stops due to a power outage or the like, the temperature rise of the solid heat conductor 212 caused by heat entering from the atmosphere through the refrigerator 206 can be slowed down. As a result, for example, even if the refrigerator 206 stops and a quench (an event in which a part of the superconducting coil returns from a superconducting state to a normal conducting state) occurs, the temperature rise of the superconducting coil 201 until the refrigerator 206 is restored can be suppressed, and the time until the cooling of the superconducting coil 201 is completed after restoration can be shortened. As a result, for example, an uninterruptible power system (UPS) prepared for power outages can be made unnecessary, and the magnetic field can be maintained for a long time.

[0067] In the example shown in Figure 3, the superconducting magnet device 200 is shown to have a pre-cooling pipe 209, but the configuration of the superconducting magnet device 200 according to the first embodiment is not limited to this, and it may not have a pre-cooling pipe 209 or a lid 218.

[0068] Figure 4 shows a modified example of the superconducting magnet device 200 according to the first embodiment.

[0069] For example, as shown in Figure 4, the superconducting magnet device 200 may have the pre-cooling pipe 209, lid 218, solid heat conductor 213, and thermal anchor 208 removed from the configuration shown in Figure 3.

[0070] In this configuration, one end of the solid heat conductor 214 is thermally in contact with the refrigerant tank 204, and the other end is thermally in contact with a point on the outer circumference of the superconducting coil 201. By directly transmitting the temperature of the refrigerant in the refrigerant tank 204 to the superconducting coil 201, the superconducting coil 201 is cooled to a second temperature.

[0071] The first embodiment has been described above, but the configurations of the superconducting magnet device and MRI device described above can also be implemented by appropriately changing some of the configurations. Therefore, the following describes modified versions of the superconducting magnet device and MRI device according to the first embodiment as other embodiments. In the following embodiments, the focus will be on the differences from the previously described embodiment, and components that perform the same role will be given the same reference numerals, and detailed descriptions will be omitted.

[0072] (Second embodiment) Figure 5 shows an example of a superconducting magnet device 300 according to the second embodiment.

[0073] For example, as shown in Figure 5, the superconducting magnet device 300 according to this embodiment differs from the superconducting magnet device 200 according to the first embodiment in that it has a solid heat conductor 301 instead of a refrigerant tank 210 and piping 211.

[0074] The solid heat conductor 301, like the solid heat conductors 212-215, is made of a metal with high thermal conductivity (for example, pure aluminum or copper), and thermally connects the refrigerant tank 204 to structures 202 and 203.

[0075] Specifically, the solid heat conductor 301 has one end in thermal contact with the refrigerant tank 204 and the other end in thermal contact with the structures 202 and 203 respectively, and cools the structures 202 and 203 to a second temperature by transmitting the temperature of the refrigerant in the refrigerant tank 204 to the structures 202 and 203.

[0076] Here, the solid heat conductor 301 has at least two parameters set from among dimensions, thermal conductivity, and thermal load, depending on the operating temperature or superconducting properties of the structure 202 and structure 203, respectively.

[0077] According to the above-described configuration, the same effects as in the first embodiment can be obtained, and compared to the first embodiment, the structure 202 can be cooled without using the refrigerant tank 210, thus reducing manufacturing costs.

[0078] (Third embodiment) Figure 6 shows an example of a superconducting magnet device 400 according to the third embodiment.

[0079] For example, as shown in Figure 6, the superconducting magnet device 400 according to this embodiment differs from the superconducting magnet device 200 according to the first embodiment in that it further includes a superconducting coil 401, a solid heat conductor 402, a connecting part 403, and a connecting part 404.

[0080] The superconducting coil 401 is composed of superconducting wires that form a magnetic field. Specifically, the superconducting coil 401 is composed of HTS material wires. Here, the superconducting coil 401 is electrically connected to structures 202 and 203.

[0081] In other words, the superconducting magnet device 400 according to this embodiment has a hybrid cooling structure that combines a superconducting coil 201 made of LTS material and a superconducting coil 401 made of HT wire material.

[0082] The solid heat conductor 402, like the solid heat conductors 212-215, is made of a metal with high thermal conductivity (for example, pure aluminum or copper), and thermally connects the refrigerant tank 204 and the superconducting coil 401.

[0083] Specifically, the solid heat conductor 402 has one end in thermal contact with the refrigerant tank 204 and the other end in thermal contact with the outer circumference of the superconducting coil 401. By propagating the temperature of the refrigerant in the refrigerant tank 204 to the superconducting coil 401, the superconducting coil 401 is cooled to a second temperature.

[0084] Here, the solid heat conductor 402 has at least two parameters set from among dimensions, thermal conductivity, and thermal load, depending on the operating temperature or superconducting properties of the superconducting coil 401.

[0085] The connection part 403 thermally connects the superconducting coil 401 and the structure 202. The connection part 404 also thermally connects the superconducting coil 401 and the structure 203. This makes it possible to equalize the temperatures of the superconducting coil 201, structure 202, structure 203, and superconducting coil 401 to a second temperature.

[0086] According to the above configuration, the same effects as in the first embodiment can be obtained, and by cooling the superconducting coil 201 and the superconducting coil 401 individually, it becomes possible to efficiently cool each superconducting coil in a hybrid cooling structure.

[0087] (Fourth embodiment) Figure 7 shows an example of a superconducting magnet device 500 according to the fourth embodiment.

[0088] For example, as shown in Figure 7, the superconducting magnet device 500 according to this embodiment differs from the superconducting magnet device 400 according to the third embodiment in that it has piping 501 instead of solid heat conductor 402.

[0089] The piping 501 is positioned to be in thermal contact with the outer circumference of the superconducting coil 401, and cools the superconducting coil 401 to a second temperature by transporting refrigerant from refrigerant tank 204 to refrigerant tank 210.

[0090] Here, the piping 501 has at least two parameters set from among dimensions, thermal conductivity, and thermal load, depending on the operating temperature or superconducting characteristics of the superconducting coil 401.

[0091] According to the above-described configuration, the same effects as in the first embodiment can be obtained, and compared to the superconducting magnet device 400 according to the third embodiment, the superconducting coil 401 can be cooled by the piping 501 through which the refrigerant flows, making it possible to cool the superconducting coil 401 more efficiently.

[0092] (Fifth embodiment) Figure 8 shows an example of a superconducting magnet device 600 according to the fifth embodiment.

[0093] For example, as shown in Figure 8, the superconducting magnet device 600 according to this embodiment differs from the superconducting magnet device 400 according to the third embodiment in that it has a solid heat conductor 601 and a coolant tank 602 instead of the solid heat conductor 402 and the connecting parts 403 and 404.

[0094] The solid heat conductor 601, like the solid heat conductors 212-215, is made of a metal with high thermal conductivity (for example, pure aluminum or copper), and thermally connects the high-temperature end 206a of the refrigerator 206 to the superconducting coil 401.

[0095] Specifically, the solid heat conductor 601 has one end in thermal contact with the high-temperature end 206a of the refrigerator 206, and the other end in thermal contact with the outer circumference of the superconducting coil 401. By propagating the temperature of the high-temperature end 206a of the refrigerator 206 to the superconducting coil 401, the superconducting coil 401 is cooled to a first temperature.

[0096] Here, the solid heat conductor 601 has at least two parameters set from among dimensions, thermal conductivity, and thermal load, depending on the operating temperature or superconducting properties of the superconducting coil 401.

[0097] The refrigerant tank 602 is in thermal contact with the superconducting coil 401 and provides auxiliary cooling to the superconducting coil 401 with a liquid or gaseous refrigerant filled inside.

[0098] With the above-described configuration, the same effects as in the first embodiment can be obtained, and compared to the superconducting magnet device 400 according to the third embodiment, the HT wire superconducting coil 401 is cooled to a first temperature, and the LTS material superconducting coil 201 is cooled to a second temperature lower than the first temperature, making it possible to cool each superconducting coil more efficiently in a hybrid cooling structure.

[0099] (Sixth embodiment) Figure 9 shows an example of a superconducting magnet device 700 according to the sixth embodiment.

[0100] For example, as shown in Figure 9, the superconducting magnet device 700 according to this embodiment differs from the superconducting magnet device 600 according to the fifth embodiment in that it has a refrigerant tank 701, a heat exchanger 702, a refrigerator 703, and piping 704 instead of a solid heat conductor 601 and a refrigerant tank 602.

[0101] Refrigerant tank 701 stores refrigerants such as liquid nitrogen and liquid hydrogen.

[0102] The heat exchanger 702 is exposed inside the refrigerant tank 701 and reliquefies the vaporized refrigerant and returns it to the refrigerant tank 701.

[0103] The refrigerator 703 cools the refrigerant in the refrigerant tank 701. Specifically, the refrigerator 703 has a high-temperature end 703a that reaches a first temperature (e.g., 50K), and cools the refrigerant in the refrigerant tank 701 to the first temperature at the high-temperature end 703a. The refrigerator 703 may also have a low-temperature end that reaches a second temperature lower than the first temperature (e.g., 4K), similar to the refrigerator 206 described in the above embodiment.

[0104] The piping 704 is positioned to be in thermal contact with the outer circumference of the superconducting coil 401, and cools the superconducting coil 401 to a first temperature by circulating the refrigerant in the refrigerant tank 701.

[0105] Here, the piping 704 has at least two parameters set from among dimensions, thermal conductivity, and thermal load, depending on the operating temperature or superconducting characteristics of the superconducting coil 401.

[0106] In other words, the superconducting magnet device 700 according to this embodiment includes a plurality of refrigerators, each configured to maintain a superconducting state against the heat load generated by the structure to be cooled, and the superconducting coil 401, which is made of HTS wire, is thermally connected to one of the plurality of refrigerators.

[0107] According to the above-described configuration, the same effects as those of the first and fifth embodiments can be obtained, and compared to the superconducting magnet device 400 according to the third embodiment, the superconducting coil 401 can be cooled by the piping 704 through which the refrigerant flows, making it possible to cool the superconducting coil 401 more efficiently.

[0108] (Seventh Embodiment) Figure 10 shows an example of a superconducting magnet device 800 according to the seventh embodiment.

[0109] For example, as shown in Figure 10, the superconducting magnet device 800 according to this embodiment differs from the superconducting magnet device 600 according to the fifth embodiment in that it has a refrigerator 801, a refrigerant tank 802 and a heat exchanger 803 instead of a solid heat conductor 601 and a refrigerant tank 602.

[0110] The refrigerator 801 cools the refrigerant in the refrigerant tank 802. Specifically, the refrigerator 801 has a high-temperature end 801a that reaches a first temperature (e.g., 50K), and cools the refrigerant in the refrigerant tank 802 to the first temperature at the high-temperature end 801a. The refrigerator 801 may also have a low-temperature end that reaches a second temperature lower than the first temperature (e.g., 4K), similar to the refrigerator 206 described in the above embodiment.

[0111] The refrigerant tank 802 stores a refrigerant such as liquid nitrogen or liquid hydrogen cooled by the refrigerator 801, and seals in the superconducting coil 401 while it is immersed in the refrigerant, thereby cooling the superconducting coil 401 to a first temperature.

[0112] The heat exchanger 803 is exposed inside the refrigerant tank 802 and reliquefies the vaporized refrigerant and returns it to the refrigerant tank 701.

[0113] In other words, the superconducting magnet device 800 according to this embodiment, similar to the sixth embodiment, includes a plurality of refrigerators, each configured to maintain a superconducting state against the thermal load generated by the structure to be cooled, and the superconducting coil 401, composed of HTS wire, is thermally connected to one of the plurality of refrigerators.

[0114] According to the above-described configuration, the same effects as those of the first and fifth embodiments can be obtained, and compared to the superconducting magnet device 700 according to the sixth embodiment, the superconducting coil 401 can be cooled more efficiently because the refrigerant stored in the refrigerant tank 802 can directly cool the superconducting coil 401.

[0115] Furthermore, in the superconducting magnet devices 300 to 800 described in the second to seventh embodiments above, similar to the modified example of the first embodiment shown in Figure 4, the pre-cooling pipe 209, lid 218, solid heat conductor 213, and thermal anchor 208 may be omitted from the configuration shown in Figures 5 to 10.

[0116] (Eighth embodiment) Figure 11 shows an example of a superconducting magnet device 900 according to the eighth embodiment.

[0117] For example, as shown in Figure 11, the superconducting magnet device 900 according to this embodiment differs from the superconducting magnet device 400 according to the third embodiment in that it has a refrigerator 901, refrigerant tank 902, heat exchanger 903 and solid heat conductor 904 instead of a refrigerant tank 204, heat exchanger 205, refrigerator 206, thermal anchor 208, pre-cooling pipe 209, refrigerant tank 210, piping 211, solid heat conductors 212-215, heat capacity holder 216, lid 218 and solid heat conductor 402.

[0118] The refrigerator 901 cools the refrigerant in the refrigerant tank 902. Specifically, the refrigerator 901 has a high-temperature end 901a that is at a first temperature (e.g., 50K) and a low-temperature end 901b that is at a second temperature lower than the first temperature (e.g., 4K), and the refrigerant in the refrigerant tank 902 is cooled to the second temperature at the low-temperature end 901b.

[0119] The refrigerant tank 902 stores a refrigerant such as liquid helium cooled by the refrigerator 901, and seals in the superconducting coil 201, structure 202, and structure 203 while they are immersed in the refrigerant, thereby cooling the superconducting coil 201, structure 202, and structure 203 to a first temperature.

[0120] The heat exchanger 903 is exposed inside the refrigerant tank 902 and reliquefies the vaporized refrigerant and returns it to the refrigerant tank 902.

[0121] The solid heat conductor 904, like the solid heat conductor 402 described in the third embodiment, is made of a metal with high thermal conductivity (for example, pure aluminum or copper), and thermally connects the refrigerant tank 902 and the superconducting coil 401.

[0122] Specifically, the solid heat conductor 904 has one end in thermal contact with the refrigerant tank 902 and the other end in thermal contact with the outer circumference of the superconducting coil 401. By transmitting the temperature of the refrigerant in the refrigerant tank 902 to the superconducting coil 401, the superconducting coil 401 is cooled to a first temperature.

[0123] Here, the solid heat conductor 904 has at least two parameters set from among dimensions, thermal conductivity, and thermal load, depending on the operating temperature or superconducting properties of the superconducting coil 401.

[0124] With the above-described configuration, the same effects as in the first embodiment can be obtained, and compared to the superconducting magnet device 400 according to the third embodiment, the superconducting coil 201, structure 202 and structure 203 can be directly cooled by the refrigerant stored in the refrigerant tank 902, making it possible to cool the superconducting coil 201, structure 202 and structure 203 more efficiently.

[0125] (Other embodiments) In the embodiment described above, an example was given in which the heat capacity holder 216 is attached only to the solid heat conductor 212. However, the embodiment is not limited to this, and for example, heat capacity holders may be similarly attached to all or some of the other solid heat conductors.

[0126] Furthermore, in the embodiments described above, the locations and number of solid heat conductors provided in the piping that transports the refrigerant from the refrigerant tank to the structure to be cooled, and the solid heat conductors that directly or indirectly thermally connect the refrigerant tank and the structure to be cooled, are not limited to the configuration described in each embodiment, and may be appropriately changed depending on the operating temperature or superconducting characteristics of the structure to be cooled. For example, solid heat conductors may be in thermal contact with multiple locations in the piping. Also, for example, solid heat conductors may be in thermal contact with multiple locations on the outer circumference of a superconducting coil. Also, for example, solid heat conductors may be in thermal contact with one or more locations on the side plate or inner circumference of a superconducting coil.

[0127] Furthermore, in the embodiments described above, a heater with adjustable temperature may be provided in place of any one of the solid heat conductor, piping, and heat capacity holder, or in addition to the solid heat conductor, piping, and heat capacity holder. In this case, the heater is in thermal contact with the structure to be cooled, and at least two of the following parameters—size, thermal conductivity, and heat load—may be set according to the operating temperature or superconducting properties of the structure to be cooled.

[0128] Furthermore, while the above description illustrates an example in which the "processor" reads and executes programs corresponding to each processing function from a memory circuit, the embodiments are not limited to this. The term "processor" refers to circuits such as a CPU (Central Processing Unit), GPU (Graphics Processing Unit), Application Specific Integrated Circuit (ASIC), and Programmable Logic Device (e.g., Simple Programmable Logic Device (SPLD), Complex Programmable Logic Device (CPLD), and Field Programmable Gate Array (FPGA)). When the processor is a CPU, for example, the processor realizes each processing function by reading and executing programs stored in a memory circuit. On the other hand, when the processor is an ASIC, instead of storing programs in a memory circuit, the processing function is directly incorporated as a logic circuit within the processor's circuit. Note that each processor in this embodiment is not limited to being configured as a single circuit for each processor; multiple independent circuits may be combined to form a single processor, and its processing functions may be realized in this way. Furthermore, the multiple components shown in Figure 1 may be integrated into a single processor to realize its processing function.

[0129] Here, the program executed by the processor is provided pre-installed in ROM (Read Only Memory) or memory circuits. This program may also be provided as a file in an installable or executable format on computer-readable storage media such as CD (Compact Disk)-ROM, FD (Flexible Disk), CD-R (Recordable), or DVD (Digital Versatile Disk). Alternatively, this program may be stored on a computer connected to a network such as the Internet and provided or distributed by downloading it via the network. For example, this program consists of modules containing the functional units described above. In actual hardware, the CPU reads the program from a storage medium such as ROM and executes it, loading each module onto the main memory and generating it in the main memory.

[0130] Furthermore, in the embodiments described above, each component of each illustrated device is a functional concept and does not necessarily have to be physically configured as shown. In other words, the specific form of distribution or integration of each device is not limited to that shown, and all or part of them can be functionally or physically distributed or integrated in any unit according to various loads and usage conditions. Moreover, each processing function performed by each device can be implemented, in whole or in any part, by a CPU and a program that is analyzed and executed by the CPU, or by hardware using wired logic.

[0131] Furthermore, among the processes described in the embodiments described above, all or part of the processes described as being performed automatically can be performed manually, or all or part of the processes described as being performed manually can be performed automatically by known methods. In addition, the processing procedures, control procedures, specific names, and information including various data and parameters shown in the above document and drawings can be arbitrarily changed unless otherwise specified.

[0132] According to at least one embodiment described above, it is possible to efficiently cool multiple structures to be cooled while reducing the amount of refrigerant.

[0133] 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 carried out in a variety of other forms, and various omissions, substitutions, modifications, and combinations of embodiments can be made 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.

[0134] With respect to the above embodiments, the following additional notes are disclosed as aspects of the invention and selective features. (Note 1) A superconducting coil composed of superconducting wires that form a magnetic field, A structure made of a superconductor and electrically connected to the superconducting coil, A refrigerant tank for storing refrigerant and sealing the structure while it is immersed in the refrigerant, A heat exchanger exposed inside the refrigerant tank, A refrigerator for cooling the aforementioned refrigerant, A solid heat conductor that directly or indirectly thermally connects the refrigerant tank and the superconducting coil, The superconducting coil, the structure, the refrigerant tank, the heat exchanger, the refrigerator, and the vacuum vessel enclosing the solid heat conductor Equipped with, The superconducting coil or the structure is composed of at least two structures with different operating temperatures or superconducting properties. Superconducting magnet device. [Explanation of Symbols]

[0135] 100 Magnetic Resonance Imaging (MRI) Equipment 200, 300, 400, 500, 600, 700, 800, 900 Superconducting Magnet Device 201,401 Superconducting Coils 202,203 Structures 204,701,802,902 refrigerant tanks 205,702,803,903 Heat exchanger 206,703,801,901 Refrigeration units 206a,703a,801a,901a High temperature end 206b,901b Low temperature end 211,501,704 Piping 212, 213, 214, 215, 301, 402, 601, 904 Solid thermal conductors 216 Heat capacity retainer 217 Vacuum container

Claims

1. A superconducting coil composed of superconducting wires that form a magnetic field, A structure made of a superconductor and electrically connected to the superconducting coil, A refrigerant tank for storing refrigerant, A heat exchanger exposed inside the refrigerant tank, A refrigerator for cooling the aforementioned refrigerant, A solid heat conductor that directly or indirectly thermally connects the refrigerant tank, the superconducting coil, and the structure, The superconducting coil, the structure, the refrigerant tank, the heat exchanger, the refrigerator, and the vacuum vessel enclosing the solid heat conductor Equipped with, The superconducting coil or the structure is composed of at least two structures with different operating temperatures or superconducting properties. Superconducting magnet device.

2. The superconducting properties are the critical temperature, critical magnetic field, or critical current. The superconducting magnet device according to claim 1.

3. The superconducting coil or structure is constructed using at least two of the following materials: low-temperature superconducting material, high-temperature superconducting material, protective material, base material, and substrate, each having different thermal conductivity or specific heat properties. The superconducting magnet device according to claim 1 or 2.

4. The solid heat conductor is made of a metal with high thermal conductivity formed in the shape of a plate, square, tape, or sheet, or a metal formed in the shape of a cylindrical pipe with a thermal conductivity set according to the structure it is in thermal contact with. The superconducting magnet device according to claim 1 or 2.

5. A piping system for transporting the refrigerant from the refrigerant tank to at least one of the structure and the superconducting coil, A heat capacity holder attached to the solid heat conductor and holding the heat capacity of the solid heat conductor, Furthermore, The superconducting magnet device according to claim 1 or 2.

6. At least one of the components among the solid heat conductor, the piping, the heat capacity holder, and the heater is in thermal contact with at least one location of the superconducting coil and the structure with a small heat capacity, and at least two parameters among the dimensions, thermal conductivity, and thermal load of the at least one component are set according to the operating temperature or the superconducting characteristics. The superconducting magnet device according to claim 5.

7. The solid heat conductor is in thermal contact with at least one location of the piping. The superconducting magnet device according to claim 5.

8. The solid heat conductor is in thermal contact with at least one location of the superconducting coil. The superconducting magnet device according to claim 1 or 2.

9. The superconducting coil or the structure contains a high-temperature superconducting material or a low-temperature superconducting material. The superconducting coil or the structure is thermally connected to either the low-temperature end or the high-temperature end of the refrigerator via at least one of the refrigerant tank, the piping, the solid heat conductor, and the refrigerant. The superconducting magnet device according to claim 5.

10. The aforementioned refrigerator includes one or more refrigerators, each configured to maintain a superconducting state against the heat load generated by the structure being cooled. The superconducting coil is thermally connected to one of the one or more refrigerators. The superconducting magnet device according to claim 9.

11. A magnetic resonance imaging apparatus comprising a superconducting magnet device according to claim 1 or 2 as a static magnetic field magnet for generating a static magnetic field in the imaging space where the subject is placed.

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