JP2018010947A - Permanent current switch and superconducting magnet device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a permanent current switch which can be cooled and heated efficiently, without installing a complex structure in the device, and to provide a superconducting magnet device using the same.SOLUTION: In a permanent current switch, a superconducting wire 2 for conducting a permanent current is wound around refrigerant piping 1, as a bobbin, and a heater 3 is wound on the outer periphery thereof, thermally in contact therewith. In a superconducting magnet device including such a permanent current switch, cooling and heating are executed with high efficiency by opening/closing a refrigerant flow rate adjustment valve, respectively, when the permanent current switch is turned ON/OFF, and operation of the permanent current switch speeds up.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a superconducting magnet that energizes a permanent current using a permanent current switch.

  The connection and disconnection of the switch can be switched stably and freely at a desired timing, and the load on the refrigerator and liquid helium for cooling the superconducting coil by the heat of the heater for disconnecting the switch is suppressed. For example, Patent Document 1 discloses the following invention regarding a permanent current switch capable of performing the following.

  According to Patent Document 1, a winding frame for winding a coil, a heater wire wound in a coil shape on the winding frame, and a switch in which a superconducting wire is wound in a coil shape so as to overlap the heater wire And a permanent current switch for intermittently connecting a superconducting circuit including a superconducting coil provided in a superconducting device cooled in a refrigerator. It is disclosed that the current switch has a through hole that allows the inside and outside of the outer cylinder member to be in communication with each other and supplies gas and / or liquid refrigerant to the inside of the outer cylinder member.

JP 2014-209543 A

  However, when the outer cylinder member is installed in a limited space in the superconducting magnet device, the form of applicable superconducting magnet device may be limited due to the complicated piping structure and physical restrictions on the installation location. .

  Accordingly, an object of the present invention is to provide a superconducting magnet device having a permanent current switch that can be widely applied to various forms of superconducting magnet devices and can be efficiently switched on and off.

In order to solve the above-mentioned problems, the present invention has various embodiments. As an example thereof, a permanent current switch formed by winding a superconducting wire non-inductively and a closed circuit connected to the permanent current switch are provided. A superconducting coil to be formed, and a protective resistor connected in parallel with the superconducting coil;
A superconducting magnet device, wherein the superconducting magnet device has a pipe through which a refrigerant flows, and the permanent current switch is formed by winding the superconducting wire around the pipe. .

  ADVANTAGE OF THE INVENTION According to this invention, it can apply widely with respect to the superconducting magnet apparatus of various forms, Comprising: The permanent current switch and superconducting magnet apparatus which can be switched on / off efficiently can be provided.

1 is a cross-sectional view including a central symmetry axis of a permanent current switch 10 according to a first embodiment of the present invention. 1 is a conceptual diagram of a cooling system of a superconducting magnet device including a permanent current switch 10 according to a first embodiment of the present invention. 1 is an electric circuit diagram of a superconducting magnet device including a permanent current switch 10 according to a first embodiment of the present invention. It is another example of the electric circuit diagram of the superconducting magnet apparatus containing the permanent current switch 10 which concerns on the 1st Example of this invention. It is sectional drawing containing the central symmetry axis of the permanent current switch 10 which concerns on the 2nd Example of this invention. It is sectional drawing containing the central symmetry axis of the permanent current switch 10 which concerns on the 3rd Example of this invention.

  In the following description of the present invention, the superconducting magnet device, its cooling system, and the problems to be considered will be described.

  A superconducting magnet device is a device that can generate a magnetic field without generating Joule loss by energizing a coil in a superconducting state having no DC resistance. In order to maintain the superconducting coil in the superconducting state, the superconducting coil is cooled using, for example, an immersion cooling method or a conduction cooling method. Immersion cooling is a cooling method in which a superconducting coil is immersed in a refrigerant typified by liquid helium or liquid nitrogen, and the conduction cooling method is performed thermally through a refrigerator or a circulated refrigerant and a metal having good thermal conductivity. It is a method of indirectly cooling by connecting to. However, even with a superconducting magnet apparatus using an immersion cooling method, for example, a medical apparatus such as an MRI (Magnetic Resonance Imaging) apparatus, an NMR (Nuclear Magnetic Resonance) apparatus, a storage ring, a synchrotron, A superconducting magnet device for research and development used for a tron radiation light source or the like operates for a long period of several months to one year. During this period, vaporization of the refrigerant progresses little by little due to heat intrusion from outside the apparatus into the apparatus, and therefore a refrigerator is provided to recondense the refrigerant.

  The energization method of the superconducting magnet device includes a power supply driving operation method in which a power source is always connected and energized, and a permanent current operation method in which the power source is connected only during excitation and the power source is disconnected after the excitation is completed. A permanent current switch exists as an indispensable component in executing the permanent current operation method. In the power drive operation system, the superconducting coil is electrically connected to the power source, and although it is designed to be thermally shut off, it is not easy to eliminate heat penetration from the outside, and it is not easy to connect to the superconducting magnet. The amount of heat penetration tends to increase. However, since the external circuit and the superconducting coil are electrically connected, there is an advantage that the stored energy can be quickly consumed by the external resistance when the magnetic field needs to be lost due to some trouble of the superconducting magnet device. In the permanent current operation system, the permanent current switch and the superconducting coil form an electric circuit that is closed, and they are all cooled. This method has an advantage that heat entry from outside is less than that of the power supply driving operation method because the low temperature part and the outside air are thermally separated. However, an external resistor for consuming stored energy must be installed in the cooling system, and a reduction in temperature rise due to heat generated by the superconducting coil and the external resistor tends to be a problem.

  In addition, the permanent current switch is required to be turned on and off as quickly as possible. The superconducting wire needs to be cooled when the permanent current switch is ON, and the superconducting wire needs to be heated when the switch is OFF. Since the cooling and heating time is the ON / OFF time of the permanent current switch, it is necessary to increase the thermal operation speed.

  In the immersion cooling method, since the superconducting coil is immersed in the refrigerant, it has a structure suitable for cooling, and the heater heat is also thermally insulated from the heater and the refrigerant so that the heater heat is effectively used for heating the superconducting coil. Is possible. On the other hand, when the conduction cooling method is adopted, cooling of the superconducting wire is performed only on the contact surface with the cooling part by conduction cooling, so that the cooling efficiency is lower than immersion cooling and the time required until the switch is turned on becomes longer. As a countermeasure against this, a cold storage material can be provided to increase the cooling efficiency, but conversely, the superconducting coil cannot be sufficiently heated by the heater when the switch is turned off, and the time required for the switch to be turned off becomes longer.

In order to operate a superconducting magnet device adopting a conduction cooling system with a permanent current, it is necessary to conduct and cool the permanent current switch together with the superconducting coil. In this method, cooling can be performed only from a portion where the cooling unit, the superconducting coil, and the permanent current switch are in thermal contact with each other, and cooling efficiency is reduced as compared with direct cooling immersed in a refrigerant having a large heat capacity.
Moreover, when installing outside a magnet apparatus, the member required for heat insulation was needed separately, and the subject that a structure became complicated occurred.

  The present invention has been made to solve the above-described problem, and a permanent current switch capable of efficiently switching on and off the permanent current switch without installing a complicated structure in the apparatus and the same It is a main object to provide a superconducting magnet device using the. Another object of the present invention is to provide various superconducting utilization devices having a cooling structure similar to that of the superconducting magnet device.

  Embodiments of the present invention will be described below with reference to the drawings.

  A permanent current switch according to a first preferred embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view including a central symmetry axis of a permanent current switch according to a first embodiment.

  In the permanent current switch of the present embodiment, as shown in FIG. 1, a superconducting wire 2 for passing a permanent current through the refrigerant pipe 1 is wound non-inductively, and the heater 3 is in thermal contact with the side surface thereof. (Hereinafter, this system is referred to as a permanent current switch 10 for convenience). The refrigerant pipe 1 is provided with a gutter 4 for fixing the superconducting wire 2 and the heater winding. In the example shown in FIG. 1, two flanges 4 are provided at a predetermined interval, and a portion sandwiched between the two flanges 4 and the flange 4 of the refrigerant pipe 1 (hereinafter referred to as a core equivalent portion 1A) is superconducting. It functions as a reel for the line 2. In addition, two or more ridges 4 may be provided instead of two. Moreover, it is desirable that the refrigerant pipe 1 and the flange 4 are made of nonmagnetic members. For example, aluminum alloy or austenitic stainless steel can be used. If these materials are used, the influence of the magnetic field generated when the superconducting coil L1 operates can be reduced, and the support structure of the permanent current switch 10 can be simplified. Further, in order to secure a contact surface between the winding structure of the superconducting wire 2 and the core equivalent portion 1A and maintain thermal conductivity, a low melting point metal sheet member is provided between the superconducting wire 2 and the core equivalent portion 1A. You may arrange. For example, an iridium sheet is a candidate.

  Moreover, the refrigerant | coolant piping 1 and the eaves 4 do not necessarily need to be the same material, and the eaves 4 may be comprised with fiber reinforced plastics, for example. Since the fiber reinforced plastic is lighter than metal, the strength required for its weight in the permanent current switch 10 of this embodiment configured by using a part of the refrigerant pipe 1 as a winding frame. This is advantageous in considering the support structure.

  Further, it is desirable to take insulation between the refrigerant pipe 1 and the flange 4 and the wound superconducting wire 2. As a method of taking insulation, for example, a member capable of maintaining mechanical strength and insulation performance at an extremely low temperature can be cited. Specifically, a polyimide film, a polyethylene film, a polyamide film, or the like can be used.

  In addition, when the wound superconducting wire 2 is further bound and fixed from the outer periphery, or when the wires are bonded to each other by an adhesive that maintains a sufficient adhesive force even under resin molding or cryogenic temperature, It is not always necessary to have the ridge 4. Further, the shape of the flange 4 is not necessarily limited to the flange shape, as long as it can prevent the wire from being collapsed.

  Next, a cooling system related to the superconducting magnet device 100 using the permanent current switch 10 shown in FIG. 1 will be described. FIG. 2 shows an example of a cooling system including the permanent current switch 10 and the object to be cooled 20 in the superconducting magnet device 100 having the permanent current switch 10 of the first embodiment.

  As shown in FIG. 2, the cooling system in the superconducting magnet device 100 of the present embodiment basically includes a refrigerant pipe 1 having a branch and serving as a refrigerant flow path, and means for changing the refrigerant flow path at the branch. And a heat transfer member that thermally connects the coolant flow path and the object to be cooled 20 to be cooled. In FIG. 2, the heat transfer member is omitted. The cooling system shown in FIG. 2 is simplified for easy understanding, and the number of branches of the refrigerant pipe 1, the number of times the refrigerant pipe 1 is wound around the object 20 to be cooled, The diameter, the number, and the bending of the pipe 1 can be arbitrarily changed as necessary.

  A more detailed description of the cooling system of the superconducting magnet device 100 is as follows.

  The refrigerant pipe 1 constituting the cooling system has at least a refrigerant inlet and a refrigerant outlet. FIG. 2 shows a case where each one is provided. However, the same number need not be provided for each. Next, the main flow of refrigerant in the cooling system will be described. The refrigerant introduced from the introduction port partially has a flow path that is divided into at least two through the branching portion. Among the refrigerant pipes divided by branching, one refrigerant pipe has a flow rate adjusting valve 11A and a permanent current switch 10 arranged in series. The other refrigerant pipe is a bypass pipe, and a flow rate adjusting valve 11B is installed as necessary in order to adjust the flow rate to the permanent current switch 10 side. In addition, the branched refrigerant pipes are unified again at the junction, and merge as refrigerant pipes for cooling the object to be cooled 20. In addition, the refrigerant whose temperature has been raised in the path from the inlet to the outlet is cooled by a refrigerator connected to the tip of the outlet, and can be used again as a refrigerant.

  Next, a method for exciting and demagnetizing the superconducting coil L1, which is the object to be cooled 20, using the permanent current switch 10 of the present embodiment will be described. FIG. 3 shows an outline of an electric circuit that the superconducting magnet apparatus 100 of the present embodiment configures. The superconducting coil L1 and the permanent current switch 10 are housed in a vacuum vessel, and a structure is adopted in which heat penetration is suppressed by a radiation shield.

  The circuit that the superconducting magnet device 100 configures mainly includes the superconducting coil L1, the protective resistor R1 connected to the superconducting coil L1, and the permanent current switch 10. The power supply 31 and the switch 32 are not included in the main configuration of the superconducting magnet device 100, but constitute the circuit during excitation.

  First, excitation of the superconducting magnet device 100 will be described. When exciting the superconducting magnet device 100, that is, exciting the superconducting coil L1, the heater 3 is heated by energization, and the superconducting wire 2 of the permanent current switch 10 is shifted to the normal conducting state. At this time, the voltage generated at both ends of the permanent current switch 10 is obtained by multiplying the excitation speed dI / dt of the power supply 31 by the inductance L of the superconducting coil L1, and is an induced voltage LdI / dt generated at both ends of the coil. This induced voltage is equal to a voltage obtained by multiplying the resistance value generated by the normal conducting transition of the superconducting wire 2 by the current flowing through the permanent current switch 10.

  During excitation of the superconducting magnet device 100, it is desirable that Joule loss generated in the permanent current switch 10 is sufficiently small. This is because there is a concern that the superconducting wire 2 may be damaged if the Joule loss is excessive. As a countermeasure, it is conceivable to suppress the current flowing into the permanent current switch 10 and measures such as designing the resistance value generated at both ends of the permanent current switch 10 to be sufficiently high are taken. 3 is inserted in parallel with the circuit composed of the superconducting coil L1 and the power source 31 while being connected in series with the diode D1. During excitation, current does not flow through the protective resistor R1 unless a voltage exceeding the turn-on voltage of the diode D1 is applied. The operation of the protective resistor R1 and the diode D1 will be described later.

  In the electric circuit described above, excitation is started when the switch 32 is turned on and a current is supplied from the power source 31 to the superconducting coil L1. The current supplied from the power supply 31 is controlled so as to increase gently until a target current to be applied to the superconducting coil L1 is reached (this is called reaching a rated state). The permanent current switch 10 is heated from the heater 3 so as to maintain a normal conduction state during excitation. After the superconducting coil L1 is excited to the rated state, the energization of the heater 3 is stopped.

  During the period in which the superconducting coil L1 is excited, the flow rate adjusting valve 11A (hereinafter referred to as the valve 11A) is closed. The valve 11 </ b> A is a member connected in series with the permanent current switch 10 with respect to the flow path of the refrigerant, and can control the amount of refrigerant flowing into the permanent current switch 10. That is, the supply of the refrigerant to the permanent current switch 10 is stopped by closing the valve 11A during the excitation period. During the excitation period, the heater 3 continues to heat the permanent current switch 10, but since the supply of the refrigerant to the permanent current switch 10 is stopped, the permanent current switch even when the amount of heat of the heater 3 is small. 10 can be quickly transferred to the normal state. In the example shown in FIG. 2, the valve 11 </ b> A is disposed in front of the permanent current switch 10 in the direction in which the refrigerant circulates. However, the valve 11 </ b> A may be disposed behind the branch portion to the junction portion. . In any case, the supply of the refrigerant to the permanent current switch 10 can be selectively stopped.

  During the period in which the superconducting coil L1 is excited, the flow rate adjusting valve 11B (hereinafter referred to as the valve 11B) is in an open state. If the valve 11B is in the open state, the refrigerant cools the superconducting coil L1 through the refrigerant pipe 1.

  Next, the operation and control of the cooling system in a state where the superconducting coil L1 has reached the rated state will be described. After the superconducting coil L1 is excited, the valve 11A is opened. When the valve 11A is in the open state, the refrigerant flowing through the refrigerant pipe 1 can flow into the path where the permanent current switch 10 is provided via the branch portion, unlike during excitation. That is, the valve 11A is means for changing the flow rate of the refrigerant with respect to the pipe provided with the permanent current switch 10 including zero. By this means, the superconducting wire 2 is cooled by flowing the refrigerant through the refrigerant pipe 1 provided with the permanent current switch 10, whereby the permanent current switch 10 becomes conductive with zero resistance (this state is referred to as the permanent current switch 10). (Referred to as ON state).

  At this time, the electric circuit is a closed circuit in which current flows through the superconducting coil L1 and the permanent current switch 10. In this state, the switch 32 can be turned off to disconnect the power source 31 from the electric circuit. The above is the method for exciting the superconducting coil L1. Note that after the superconducting coil L1 reaches the rated state, the valve 11B may be closed, and control may be performed so as to flow intensively with respect to the refrigerant pipe 1 provided with the permanent current switch 10. By supplying the refrigerant to the permanent current switch 10 in a concentrated manner, the permanent current switch 10 is cooled more quickly, and can be shifted more quickly from the normal conduction state to the superconducting state.

  Next, a method for demagnetizing the superconducting coil L1 will be described. If an abnormality occurs during operation of the superconducting magnet device 100, it is necessary to shift the permanent current switch 10 from the superconducting state to the normal conducting state. In this case, the superconducting wire 2 of the permanent current switch 10 can be efficiently transferred to normal conduction by supplying current to the heater 3 after the valve 11A is closed. By closing the valve 11A, the supply of the refrigerant to the permanent current switch 10 can be selectively stopped. The superconducting wire 2 transitioned to normal conduction has an electric resistance, and a voltage calculated by the generated resistance and the energization current is generated at both ends of the permanent current switch 10.

  By selecting the turn-on voltage of the diode D1 to be lower than the voltage generated at both ends of the permanent current switch 10 at the time of demagnetization, a current flows through the conductor including the diode D1 and the external resistor R1, The energy stored in the superconducting coil L1 is consumed by Joule heat generation, and the magnetic field can be lost. The turn-on voltage is determined based on the durability of the superconducting wire 2 and the magnitude of current in the rated state.

  In addition, when the stored energy is consumed, the superconducting coil L1 is actively subjected to normal conduction transition, and energy is distributed and consumed using the superconducting coil L1 that has undergone normal conduction transition together with the external resistor R1, thereby shortening the demagnetization time and increasing local temperature Can be suppressed. In that case, for example, as shown in FIG. 4, a heater resistor R2 is added to the current path including the diode D1 and the external resistor R1 in order to thermally transfer the superconducting coil L1 to the normal conducting state, and the superconducting coil L1 is thermally Make contact. The current flowing through the heater resistor R2 may be supplied from an external power source.

  As described above, the superconducting magnet device 100 of the present embodiment includes the permanent current switch 10 having a part of the refrigerant pipe as a winding frame. Further, the refrigerant pipe 1 forms a pipe-shaped portion where the flow path branches and merges again in at least one place, and the permanent current switch 10 is provided in one of the branched refrigerant pipes. Further, there is provided means for supplying and stopping the refrigerant to the refrigerant pipe to which the permanent current switch 10 is fixed during the period from the branching to the merge. This means is, for example, a valve 11A as shown in FIG.

  As a result of having the cooling system configured as described above, the superconducting magnet device 100 according to the first embodiment can quickly perform the ON / OFF operation of the permanent current switch 10 while performing the permanent current operation by the conduction cooling method. Become. Further, since the permanent current switch 10 is formed by using a part of the refrigerant pipe 1 as a winding frame, a space necessary for installing the permanent current switch 10 inside the superconducting magnet device 100 can be reduced. .

  In the above-described example, the valve 11B is provided in the refrigerant pipe 1, but it may not be provided as long as sufficient refrigerant can be supplied to the permanent current switch 10 after excitation. Moreover, although the example shown in FIG. 2 showed the case where the branch part of the refrigerant | coolant piping 1 was provided ahead of the part which cools the to-be-cooled target 20 in the direction through which a refrigerant | coolant flows, a branch part is to be cooled. It may be provided at the same position or behind it.

  A permanent current switch 10 according to a preferred second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view including the central symmetry axis of the permanent current switch 10 according to the second embodiment. Since the ON / OFF control of the permanent current switch 10 and the excitation / demagnetization method of the superconducting magnet device 100 in this embodiment are the same as those in the above-described embodiment, the description thereof is omitted.

  In the permanent current switch 10 of the present embodiment, a part of the refrigerant pipe 1 is composed of a combination of different materials. Specifically, the core equivalent portion 1A around which the superconducting wire 2 is wound is formed of a high heat conductive member. The piping part 1B which comprises the both ends is formed of a low heat conductive member having a relatively lower thermal conductivity than the high heat conductive member forming the core equivalent part 1A. The refrigerant pipe 1 is a pipe formed by joining the core equivalent part 1A and the pipe part 1B to each other. Thereby, in the process of exciting the superconducting coil L1, the temperature of the refrigerant pipe 1, particularly the core equivalent portion 1A, is uniformly and quickly cooled by the refrigerant. For example, high-purity copper or aluminum can be used as the high heat conductive member, and stainless steel or the like can be used as the low heat conductive member. Further, in the process of demagnetizing the superconducting coil L1, when the superconducting wire 2 is heated by the heater 3, the heat of the heater 3 is efficiently transferred to the superconducting wire 2 without diffusing heat around the permanent current switch 10. be able to.

  In addition, all the piping corresponding to the branch part provided with the permanent current switch 10 is configured by a high heat conductive member, and is configured by a low heat conductive member centering on other piping, particularly piping not used for cooling the object to be cooled 20. May be. In this case, for example, in the example illustrated in FIG. 2, in the branch portion of the refrigerant pipe 1, the pipe provided with the permanent current switch 10 is configured with a high heat conductive member, and the other pipe is configured with a low heat conductive member. Is done.

  A preferred third permanent current switch 10 of the present invention will be described with reference to FIG. FIG. 6 is a cross-sectional view including the central axis of symmetry of the permanent current switch 10 according to the third embodiment.

The permanent current switch 10 of this embodiment has a configuration in which a superconducting wire 2 and a refrigerant pipe 1C are wound together around a conductor winding frame 30, and a heater 3 is wound around the outer periphery of the superconducting wire 2. That is, the refrigerant pipe 1 </ b> C in the present embodiment is a modification of the pipe provided with the permanent current switch 10 in the branched portion in FIG. 2. In the present embodiment, the refrigerant pipe 1 itself is not used as a winding frame of the permanent current switch 10. ON / OFF of the permanent current switch 10 in this embodiment
The OFF control is the same as in the above embodiment. When the permanent current switch is ON, the superconducting wire 2 that is in thermal contact with the refrigerant pipe 1C is cooled by cooling the refrigerant.

  When the permanent current switch is OFF, the superconducting wire 2 is thermally transferred to normal conduction by energizing the heater 3. At this time, the refrigerant pipe 1C and the heater 3 are arranged in a thermally non-contact manner so that the heat of the heater 3 is not removed by the refrigerant. By adopting such a structure, even when the superconducting wire 2 of the permanent current switch 10 has a multi-layer structure, cooling with a refrigerant can be performed with high efficiency.

  Although the embodiments of the present invention have been described with reference to a plurality of examples, the embodiments of the present invention are not limited to these. The member to be used, the structure of the refrigerant pipe 1, the number of superconducting coils installed can be changed as appropriate. The superconducting magnet device 100 described in each embodiment can be used for a magnetic resonance imaging apparatus, a charged particle beam deflecting electromagnet, or the like. By using these devices, efficient excitation and demagnetization can be performed, which can contribute to improvement of convenience of these devices.

DESCRIPTION OF SYMBOLS 1 Refrigerant piping 1A Winding core equivalent part 1B Piping part 1C Refrigerant piping 2 Superconducting wire 3 Heater 4 鍔 10 Permanent current switch 11A, 11B Flow rate adjustment valve 20 Object to be cooled (superconducting coil L1)
30 Conductor frame 31 Power supply 32 Switch 100 Superconducting magnet device R1 External resistance (protection resistance)
D1 Diode L1 Superconducting coil R2 Heater resistance

Claims (7)

A permanent current switch formed by winding a superconducting wire non-inductively,
A superconducting coil connected to the permanent current switch to form a closed circuit;
A protective resistor connected in parallel with the superconducting coil;
A superconducting magnet device comprising:
The superconducting magnet device has a pipe through which a refrigerant flows,
The permanent current switch is a superconducting magnet device in which the superconducting wire is wound around the pipe. The superconducting magnet device according to claim 1,
A bypass pipe provided for the pipe around which the permanent current switch is wound;
A flow rate changing means for changing a flow rate of the refrigerant with respect to the pipe around which the permanent current switch is wound;
A superconducting magnet device. The superconducting magnet device according to claim 1 or 2, wherein
The pipe around which the permanent current switch is wound is made of at least two kinds of materials, and the material forming the part that contacts the superconducting wire has higher thermal conductivity than the material forming the other part. Magnet device. The superconducting magnet device according to any one of claims 1 to 3,
A heater composed of a heater wire wound together with the superconducting wire with respect to the pipe;
A superconducting magnet device in which the superconducting wire forming the permanent current switch is disposed between the pipe and the heater wire. The superconducting electromagnet device according to any one of claims 1 to 4,
A duct disposed in a magnetic field space formed by the superconducting magnet device and through which a charged particle beam passes;
A deflection electromagnet apparatus comprising: The superconducting electromagnet device according to any one of claims 1 to 4,
A bed on which the subject is placed;
Transport means for moving the bed and transporting the subject to a uniform magnetic field space generated by the superconducting electromagnet apparatus;
Analyzing means for analyzing a nuclear magnetic resonance signal from the subject placed in the uniform magnetic field space;
A magnetic resonance imaging apparatus comprising:   A permanent current switch formed by winding a superconducting wire around a pipe that transmits refrigerant.

Images