JP7370307B2 - Superconducting magnet device - Google Patents

Description

The present application relates to a superconducting magnet device.

In recent years, progress has been made in the development of superconducting wires in which a superconductor is embedded in a metal sheath or a superconducting thin film is formed on a substrate. Among these, oxide-based superconducting wires provided with a superconducting layer made of an oxide-based superconductor, which is a high-temperature superconductor whose transition temperature is higher than the liquid nitrogen temperature, are attracting attention. Superconducting coils formed by winding oxide-based superconducting wires are used in magnetic resonance diagnostic equipment (MRI), nuclear magnetic resonance analyzers (NMR), and other superconducting magnet devices that require a high-strength magnetic field. A technique has been proposed to generate a magnetic field using

In the above superconducting magnet device, in order to achieve high diagnostic accuracy, it is required to generate a magnetic field that is temporally stable and has high spatial uniformity. However, in superconducting coils made of oxide-based superconducting wires, the magnetic field distribution is distorted due to the influence of an additional magnetic field (hereinafter referred to as the shielding current magnetic field) generated inside the coil by the shielding current induced in the superconducting layer. However, there are technical issues such as magnetic fields that occur or that the magnetic field fluctuates over time.

This is because most oxide-based superconducting wires have a tape shape with a high aspect ratio for manufacturing reasons. In a superconducting coil wound with oxide-based superconducting wire, magnetic flux is applied perpendicularly to the wide surface during excitation, so a magnetic field (shielding current magnetic field) that is in the opposite direction to the magnetic field that is originally desired to be generated due to electromagnetic induction is generated. It is known from many previous studies that this phenomenon occurs.

Furthermore, in a superconducting coil in which an oxide-based superconducting wire is wound, there is a phenomenon in which localized heat generation (so-called hot spots) occurs inside the coil. Hot spots can occur anywhere in the superconducting wire inside the coil, and it is difficult to reliably prevent them by monitoring or protecting only specific areas. Once a hot spot is formed, it can rapidly generate heat and lead to burnout, so there is also a technical issue in that it is necessary to prevent damage to the superconducting coil when a hot spot occurs.

On the other hand, for example, in the method of operating a superconducting magnet device disclosed in Patent Document 1, the superconducting coil is heated to a first temperature during excitation, and after the superconducting coil is excited to the rated value, the superconducting coil is heated to the first temperature. A method is described that can suppress temporal changes in shielding current by cooling to a second temperature lower than the first temperature. At this time, it is described that in order to raise the temperature of the superconducting coil, the influence of the shielding current magnetic field is reduced in a short time by heating a cooling plate installed at the end of the superconducting coil.

JP 2017-33977 Publication Hirofumi Wada, Masayuki Shiga, “Magnetocaloric effect of compounds exhibiting first-order magnetic phase transition - Aiming for highly efficient magnetic refrigeration -”, Materia Vol. 39, No. 11 (2000)

However, with the method disclosed in Patent Document 1, it is difficult to control the contact state between the cooling plate and the end of the superconducting coil, it is not easy to uniformly warm the superconducting coil, and there are problems in that it is difficult to control the temperature of the superconducting coil. In addition, if there is a small defect in the superconducting coil and a hot spot occurs, most of the magnetic energy of the superconducting coil will be consumed in the hot spot, which may lead to burnout of the superconducting coil. There were such issues.

The present application was made to solve the above-mentioned problems, and is intended to reduce the influence of the shielding current magnetic field and prevent burnout of the superconducting coil in a superconducting magnet device equipped with a superconducting coil having a wound superconducting wire. The object of the present invention is to provide a superconducting magnet device that can suppress the occurrence of.

The superconducting magnet device disclosed in this application includes a superconducting coil around which a superconducting wire is wound, a power source that supplies current to the superconducting coil, a conducting wire wound around the superconducting coil via an insulating material, and cooling the superconducting coil. A heating means for generating heat in the superconducting wire or the conducting wire, and a consuming means for consuming the energy stored in the conducting wire. , and a changeover switch for switching between the heat generating means and the consumption means .

According to the superconducting magnet device disclosed in the present application, when it becomes necessary to urgently demagnetize the superconducting coil, energy can be consumed by the energy consuming means connected in parallel to the conductive wire wound around the superconducting coil. This has the effect of suppressing the occurrence of burnout of the superconducting coil.

1 is a schematic configuration diagram of a superconducting magnet device according to Embodiment 1. FIG. FIG. 3 is a diagram showing an electric circuit of a superconducting coil and a conducting wire in Embodiment 1. FIG. 2 is a cross-sectional view showing the configuration of a superconducting coil and a conducting wire in Embodiment 1. FIG. 3 is a diagram showing an electric circuit of a superconducting coil and a conducting wire used in simulation in Embodiment 1. 5 is a diagram showing a current waveform based on the simulation result of FIG. 4. FIG. FIG. 7 is a perspective view showing the configuration of a superconducting coil, a first conducting wire, and a second conducting wire in Embodiment 2. FIG. FIG. 7 is a diagram showing an electric circuit of a superconducting coil, a first conductive wire, and a second conductive wire in Embodiment 2. FIG.

Embodiment 1.
FIG. 1 is a schematic configuration diagram of a superconducting magnet device according to Embodiment 1, and FIG. 2 is a diagram showing an electric circuit of a superconducting coil and a conducting wire of the superconducting magnet device shown in FIG. 1. FIG. 3 is a cross-sectional view showing the structure of a superconducting coil and a conducting wire. FIG. 4 is a diagram showing an electric circuit of a superconducting coil and a conducting wire used in the simulation. Further, FIG. 5 is a diagram showing a current waveform based on the simulation result of FIG. 4.

First, details of each part constituting the superconducting magnet device 1 according to the first embodiment will be explained with reference to FIGS. 1 and 2.
A superconducting magnet device 1 houses a superconducting coil 2 around which a superconducting wire 21 is wound, a conducting wire 3 that is wound around the superconducting coil 2 and is covered with an insulating material 31, and the superconducting coil 2, and is heat-insulated from the outside. A vacuum container 4, a refrigerator 5 which is a cooling means for the superconducting coil 2, a superconducting coil power source 7 which excites the superconducting coil 2, a heat generating means 8 which causes the conducting wire 3 to generate heat, and a consuming means 9 which consumes the energy of the conducting wire 3. , a changeover switch 10a that switches between the heat generating means 8 and the consumption means 9, and a cutoff switch 10b that cuts off the superconducting coil current source 72. In the embodiment, a case will be described in which an oxide-based superconducting wire is used as the superconducting wire 21.

The vacuum container 4 plays a role of insulating the outside of the container and the superconducting coil 2. Generally, the superconducting coil 2 is operated at a temperature of 20K or less, so the vacuum vessel 4 only needs to be able to reduce heat intrusion into the superconducting coil 2 due to radiant heat from the outside, and a radiant heat shield is used for the vacuum vessel 4. It may be a configuration. Although not shown, the vacuum vessel 4 may be a known cryogenic vacuum vessel called a cryostat made of stainless steel, aluminum alloy, other metals, reinforced fiber plastic (FRP), or the like.

Next, the superconducting coil 2 is cooled by the refrigerator 5. The refrigerator 5 includes a compressor 54, a cold head 51, and a hose 53 connecting the cold head 51 and the compressor 54. The refrigerator 5 may be a known refrigerator, such as a Gifford-McMahon refrigerator, a Stalin refrigerator, or a pulse tube refrigerator. The refrigerator 5 is connected to the superconducting coil 2 via a heat transfer path formed by a first good thermal conductor 61 and a second good thermal conductor 62. The first thermal conductor 61 is fastened or bonded to the refrigerator 5 and the second thermal conductor 62, and the second thermal conductor 62 is cooled via the first thermal conductor 61.

Note that the connection mode between the first good thermal conductor 61 and the second good thermal conductor 62 shown in FIG. may have been done. Further, the first good thermal conductor 61 and the second good thermal conductor 62 may each be formed of a single member, or may be formed by combining members formed from a plurality of good thermal conductors. good. This heat transfer path can take any form as required. As the first good thermal conductor 61 and the second good thermal conductor 62, pure aluminum, oxygen-free copper, or other metals that have high thermal conductivity at extremely low temperatures can be used.

Furthermore, the rigidity of the first good thermal conductor 61 and the second good thermal conductor 62 can be changed arbitrarily according to the required specifications, so that the thermal stress caused by thermal contraction when the superconducting coil 2 is cooled can be changed. For relaxation, it is also possible to use a flat braided conductor or the like that can be bent with a certain degree of curvature. Note that the cooling unit for cooling the superconducting coil 2 may have a configuration in which the superconducting coil 2 is immersed in a refrigerant such as liquid helium, liquid nitrogen, or liquid hydrogen contained in the vacuum container 4 instead of using the refrigerator 5. good.

The superconducting coil power source 7 plays a role of exciting the superconducting coil 2. As shown in FIG. 1, the superconducting coil power source 7 is connected to the superconducting coil 2 housed in the vacuum container 4 via a lead wire 71. Further, as shown in FIG. 2, the superconducting coil power source 7 generally includes a superconducting coil current source 72 and a protective resistor 73 connected in parallel to the superconducting coil 2, and a diode connected in series to the protective resistor 73. (not shown) is inserted. Further, in FIG. 2, a configuration may be adopted in which a switch element called a persistent current switch for flowing a persistent current in the current closed circuit of the superconducting coil is added in parallel to the superconducting coil power source 7 and the superconducting coil 2.

The conducting wire 3 is covered with an insulating material 31 and wound around the superconducting coil 2, and as shown in FIG. consuming means 9. Furthermore, it has a changeover switch 10a for switching between the heat generating means 8 and the consumption means 9. The changeover switch 10a may be a physical switch, a semiconductor switch, or the like, and its type is not particularly limited.

The heating means 8 generates heat by passing current through the conducting wire 3 using, for example, a current source for the conducting wire that supplies a current for causing the conducting wire 3 to generate heat.

The consuming means 9 consumes the energy of the conductor 3, and for example, the conductor 3 may be electrically connected by short-circuiting both ends of the conductor 3 to consume energy by heat generated by the resistance of the conductor 3 itself, or Other than the method of consuming energy by the resistance of the conductor 3 or the heat generation of the resistor by providing a resistor at both ends of the conductor 3 and electrically connecting it, there is no particular limitation on the method.

Next, the structures of the superconducting coil 2 and the conducting wire 3 will be explained. FIG. 3 shows a cross-sectional view of the superconducting coil 2 and three turns of the conducting wire 3. The superconducting coil 2 is manufactured by winding a superconducting wire 21, and the superconducting wire 21 has a tape shape with a high aspect ratio for manufacturing reasons. The conducting wire 3 has a structure wound around the superconducting coil 2, and has a structure covered with an insulating material 31 and electrically insulated. For example, the electrical conductor 3 may be insulated by forming an enamel coating, or by wrapping a commercially available insulating tape such as Kapton tape or polyimide tape to serve as an insulating material. Alternatively, a structure may be adopted in which the conducting wire 3 is not coated with insulation, but the superconducting wire 21 is coated with insulation.

Next, a method of exciting the superconducting magnet device 1 according to this embodiment will be explained.
By adopting a structure in which the conducting wire 3 is wound around the superconducting coil 2, the temperature of the superconducting coil 2 can be controlled by heat generation of the conducting wire 3. Before the excitation of the superconducting coil 2 is completed, the conducting wire 3 generates heat by passing a current through the conducting wire 3, thereby increasing the temperature of the conducting wire 3. Here, since the conducting wire 3 is wound around the superconducting coil 2, heat transfer between them is performed efficiently, and as a result, the temperature of the superconducting coil 2 also increases.

Here, before the excitation of the superconducting coil 2 is completed, the temperature of the superconducting coil 2 is raised to the first target temperature by the heating means 8, and after the excitation of the superconducting coil 2 is completed, the heating means 8 is released, and the refrigerator is By lowering the temperature of the superconducting coil 2 to the second target temperature lower than the first target temperature by 5, the critical current of the superconducting coil 2 is lower than when exciting at the second target temperature. The amount of induced shielding current is smaller than when exciting at the first target temperature. Therefore, after completion of excitation, the critical current is improved by lowering the temperature to the second target temperature, and the pinning force of the superconducting material in the superconducting layer of the superconducting wire 21 can be made larger than the first target temperature. , it becomes possible to suppress fluctuations in the shielding current magnetic field.

After the excitation of the superconducting coil 2 at the first target temperature is completed, the heating means 8 becomes unnecessary and the circuit of the conducting wire 3 is switched to the consuming means 9. As a result, in the unlikely event that the superconducting coil 2 needs to be urgently demagnetized due to a hot spot due to a minute defect, quenching due to magnetic instability, or other factors, the superconducting coil ² can be The energy E of No. 2 can be consumed not only in the electric circuit of the superconducting coil 2 including the protective resistor 73, but also in the electric circuit of the magnetically coupled conducting wire 3. Here, let L be the inductance of the superconducting coil 2, and I be the current of the superconducting coil 2. As a result, the electrical circuit of the conducting wire 3 will be responsible for part of the energy consumption of the superconducting coil 2, so the energy consumed by the electrical circuit of the superconducting coil 2 including the protective resistor 73 can be reduced. This makes it possible to prevent burnout of superconducting coils.

FIG. 4 shows an electric circuit diagram when the superconducting coil current source 72 is cut off by the cutoff switch 10b in case emergency demagnetization is required. Here, a case is shown in which a resistor 91 is used as the consumption means 9 that consumes energy. Further, FIG. 5 shows simulation results (current waveforms of the superconducting coil 2 and the conducting wire 3) in the electric circuit of FIG. 4. Here, as an example, the inductance of the superconducting coil 2 is 10H, the value of the protective resistor 73 connected in parallel with the superconducting coil 2 when viewed from the superconducting coil current source 72 is 1Ω, and the rated current value of the superconducting coil 2 is 200A, the inductance of the conductor 3 was 10H, the coupling coefficient between the superconducting coil 2 and the conductor 3 was 0.98, and the resistance 91 of the conductor 3 was 1Ω.

FIG. 5 shows current changes in the superconducting coil 2 and the conducting wire 3. Note that the emergency degaussing start point is set to time 0 seconds. In the electrical circuit shown in FIG. 4, 200 kJ of energy of the superconducting coil 2 is consumed in the electrical circuit composed of the superconducting coil 2 and the protective resistor 73, and the electrical circuit composed of the conducting wire 3 and the resistor 91. Here, for simplicity, it is assumed that the superconducting coil 2 and the conducting wire 3 have only inductance and no resistance. In the case of the above parameters, the energy consumed in the electric circuit of the superconducting coil 2 and the protective resistor 73 is 104 kJ, and the energy consumed in the electric circuit of the conducting wire 3 and the resistor 91 is 96 kJ.

On the other hand, when the conducting wire 3 is not magnetically coupled to the superconducting coil 2 (when the coupling coefficient is zero), the energy of 200 kJ of the superconducting coil 2 is consumed only by the superconducting coil 2 and the protective resistor 73. Ru. Therefore, the energy consumed by the superconducting coil 2 and the protective resistor 73 is approximately half that of an electric circuit including only the superconducting coil 2 and the protective resistor 73. This result shows that the occurrence of burnout in the superconducting coil 2 can be suppressed.

As described above, according to the superconducting magnet device according to the first embodiment, when it becomes necessary to urgently demagnetize the superconducting coil, the energy consuming means connected in parallel to the conductive wire wound around the superconducting coil can demagnetize the superconducting coil. By consuming energy, it is possible to suppress the occurrence of burnout of the superconducting coil.

Embodiment 2.
FIG. 6 is a perspective view showing the structure of the superconducting coil, the first conducting wire, and the second conducting wire in the second embodiment, and FIG. 7 is a perspective view showing the configuration of the superconducting coil, the first conducting wire, and the second conducting wire in the second embodiment. FIG. 3 is a diagram showing an electric circuit of conductive wires. The difference from Embodiment 1 is that in Embodiment 2, the conducting wire is composed of a first conducting wire and a second conducting wire. The other configurations are the same as those in Embodiment 1, so explanations will be omitted.

Embodiment 2 shows another configuration in which the conducting wire 3 is heated by current application. As shown in FIG. 6, the conducting wire 3 in the second embodiment is covered with an insulating material 31 and is composed of a first conducting wire 3a and a second conducting wire 3b arranged in parallel, and is wound around the superconducting coil 2. and is insulated.

When exciting the superconducting coil 2, one end of the first conducting wire 3a and one end of the second conducting wire 3b are connected so that current flows in the same direction and in opposite directions to the superconducting coil 2, respectively. ing. Further, the first conducting wire 3a and the second conducting wire 3b are insulated except for their both ends, and are also insulated from the superconducting coil 2. This configuration is known as a non-inductive winding, and the currents flowing through the first conductor 3a and the second conductor 3b are always 180° different in phase and in opposite directions, so they are mutually opposite. The generated magnetic fields can be canceled out. Therefore, the induced voltage generated when a varying current is passed through the first conductive wire 3a and the second conductive wire 3b is almost the same as the induced voltage due to the first conductive wire 3a and the induced voltage due to the second conductive wire 3b. It becomes zero. This makes it possible to reduce the power capacity of the power supply when passing current, thereby achieving cost reduction and downsizing.

FIG. 7 shows an example of an electric circuit diagram having the above effect. When heating the first conductive wire 3a and the second conductive wire 3b, current is applied by the conductor current source 11 to heat the first conductive wire 3a and the second conductive wire 3b by the resistance 121 of the first conductive wire and the resistance 122 of the second conductive wire. When heating, the switch 101 is opened, the switch 102 is shorted, and the switch 103 is opened, so that currents in opposite directions are passed through the first conducting wire 3a and the second conducting wire 3b.

When the superconducting coil 2 is in steady operation, one end of the first conducting wire 3a and one end of the second conducting wire 3b are electrically connected, and the other end of the first conducting wire 3a and the other end of the second conducting wire 3b are electrically connected. By connecting the superconducting coil 2 and the conductive wire 3, the magnetic coupling between the superconducting coil 2 and the conducting wire 3 can be increased. By shorting the switch 101, opening the switch 102, and shorting the switch 103 in FIG. 7, the energy of the superconducting coil 2 can be consumed in the circuit of the first conducting wire 3a and the circuit of the second conducting wire 3b. The switching of the electric circuit described above may be a physical switch or a semiconductor switch, and the type thereof is not particularly limited.

As described above, according to the superconducting magnet device according to the second embodiment, when it becomes necessary to urgently demagnetize the superconducting coil, the energy of the superconducting coil can be consumed by the electric circuit of the first conducting wire and the second conducting wire. Therefore, similarly to the first embodiment, there is an effect that it is possible to suppress the occurrence of burnout of the superconducting coil.

Embodiment 3.
The superconducting magnet device according to Embodiment 3 is related to the structure of the conductive wire which is wound around the superconducting coil described in Embodiment 1 and is insulated, and the difference from Embodiment 1 is as follows. In No. 3, there is another configuration in which the conducting wire is heated by applying current. Except for this point, the configuration of the superconducting magnet device of Embodiment 3 is the same as that of Embodiment 1, so the explanation will be omitted.

When a current is applied to the superconducting coil 2 around which the superconducting wire 21 is wound, a magnetic field distribution is formed. Since the magnetic field strength or magnetic field direction differs depending on the position of the superconducting wire 21, the electromagnetic load on the superconducting wire 21 differs depending on the position. The amount of shielding current induced by this electromagnetic load and the amount of variation in the magnetic field perpendicular to the wide surface of the superconducting wire 21 differs, and the influence of the shielding current on the magnetic field also changes. Therefore, by making the cross-sectional area of the conductor 3 different depending on the position, a large amount of shielding current is induced, and in places where the influence on the design magnetic field is large, the amount of heat generated by the conductor 3 is increased, and the influence on the design magnetic field is small. However, by reducing the amount of heat generated by the conducting wire 3, the amount of heat generated inside the superconducting coil 2 can be controlled.

For example, when the superconducting coil 2 has a solenoid coil shape, the location where the vertical magnetic field is largest in the wound superconducting wire 21 is at the end of the superconducting coil 2 in the axial direction. The amount of induced shielding current depends on the magnetic field strength, so strictly speaking, it is different, but basically the amount of induced shielding current depends on the amount of change in the vertical magnetic field of the superconducting wire 21, so if the shielding current is large The induced point is the end of the superconducting coil 2 in the axial direction. That is, in order to reduce the degree of influence of the shielding current on the designed magnetic field, it is effective to reduce the influence of the shielding current at the axial end of the superconducting coil 2.

Furthermore, in order to increase the amount of temperature change at the end of the superconducting coil 2, the cross-sectional area of the conducting wire 3 wound around the superconducting coil 2 is reduced, thereby increasing the amount of heat generated by the conducting wire 3. On the other hand, since the amount of induced shielding current is relatively small in the center of the superconducting coil 2, the amount of temperature change may be small, and energy savings can be achieved by reducing unnecessary heat generation. Therefore, the cross-sectional area of the conducting wire 3 may be large.

As described above, the superconducting magnet device according to the third embodiment has the same effects as the first embodiment, and also optimizes the heat generation amount of the conductor according to the degree of influence of the shielding current magnetic field on the design magnetic field. Therefore, by optimizing the amount of heat generated, energy saving is achieved by reducing unnecessary heat generation, and by effectively reducing the amount of induced shielding current, a magnetic field with high precision relative to the design magnetic field can be achieved. It has the effect of being able to realize the following.

Embodiment 4.
The superconducting magnet device according to Embodiment 4 relates to the heating means of the conducting wire described in Embodiment 1, and the difference from Embodiment 1 is that in Embodiment 4, the conducting wire is made of a magnetocaloric material. The point is that it is structured. Except for this point, the configuration of the superconducting magnet device of Embodiment 4 is the same as that of Embodiment 1, so a description thereof will be omitted.

According to Non-Patent Document 1, magnetic materials such as erbium cobalt nickel have been discovered as magnetocaloric materials having a magnetic transition point near 10 to 20 K, which is the operating temperature of the superconducting coil 2. In this magnetocaloric material, when a change in the magnetic field occurs near the magnetic transition point, a heat generating/endothermic effect called a magnetocaloric effect can be obtained. Generally, when the magnetic field applied to a magnetocaloric material increases, it generates heat, and when the applied magnetic field decreases, it produces an endothermic effect.

By adding a magnetocaloric material having this characteristic to the superconducting wire 21, the conducting wire 3, or the resin used to maintain the shape of the superconducting coil 2, the magnetocaloric material is not applied to the magnetocaloric material during excitation of the superconducting coil 2. When the magnetic field increases, this magnetocaloric material generates heat, and the temperature of the superconducting coil 2 increases. Further, by making this magnetocaloric material into powder form, the amount added can be controlled, and as a result, the calorific value of the magnetocaloric material can also be controlled. Thereby, the temperature of the superconducting coil 2 can also be controlled, and the temperature of the superconducting coil 2 as shown in Embodiment 1 can be controlled and raised.

Therefore, by using a magnetocaloric material as a heat generating means, the amount of heat generated by the superconducting coil can be controlled. Since the magnetocaloric material operates passively, it is not necessary to have a complicated control mechanism, and it becomes possible to realize a heat generating means at low cost.

As described above, the superconducting magnet device according to the fourth embodiment has the same effect as the first embodiment, and also maintains the shape of the superconducting wire, conducting wire, or superconducting coil by using a magnetocaloric material as the heat generating means. By adding it to the resin used for this purpose, the temperature of the superconducting coil can be controlled by utilizing the phenomenon in which the magnetic material generates heat due to the applied magnetic field.

In addition, in the above embodiment, the case where mainly an oxide-based superconducting wire having a high aspect ratio is used as the superconducting wire has been described as an example, but it is also possible to provide a heating means to an insulated conducting wire wound around a superconducting coil. The method of controlling the temperature of the superconducting coil and consuming the energy of the superconducting coil by adding the superconducting wire is not limited to the case where the superconducting wire is an oxide-based superconducting wire. Further, in the above embodiment, a case has been described in which an oxide-based high temperature superconducting wire is used as the superconducting wire, but similar effects can be expected when using a low temperature superconducting wire such as NbTi or Nb3Sn.

Additionally, while this application describes various exemplary embodiments and example implementations, the various features, aspects, and functions described in one or more embodiments may differ from those described in a particular implementation. The present invention is not limited to the application of the embodiments, but can be applied to the embodiments alone or in various combinations.
Accordingly, countless variations not illustrated are envisioned within the scope of the technology disclosed herein. For example, this includes cases where at least one component is modified, added, or omitted, and cases where at least one component is extracted and combined with components of other embodiments.

Moreover, in the figures, the same reference numerals indicate the same or corresponding parts.

1 superconducting magnet device, 2 superconducting coil, 21 superconducting wire, 3 conducting wire, 3a first conducting wire, 3b second conducting wire, 31 insulating material, 4 vacuum container, 5 refrigerator, 51 cold head, 53 hose, 54 compressor, 61 first thermal conductor, 62 second thermal conductor, 7 superconducting coil power source, 71 lead wire, 72 superconducting coil current source, 73 protective resistor, 8 heating means, 9 consuming means, 91 resistor, 10a changeover switch, 10b cutoff switch, 101, 102, 103 switch, 11 current source for conducting wire, 121 resistance of first conducting wire, 122 resistance of second conducting wire

Claims (6)

A superconducting coil wound with superconducting wire,
a power source that supplies current to the superconducting coil;
a conducting wire wound around the superconducting coil via an insulating material;
means for cooling the superconducting coil;
a heat generating means for causing the superconducting wire or the conducting wire to generate heat;
consuming means for consuming the energy stored in the conductive wire ,
The circuit of the conducting wire includes a portion wound around the superconducting coil, the heating means, the consuming means, and a changeover switch for switching between the heating means and the consuming means.
A superconducting magnet device characterized by: Before completion of excitation of the superconducting coil, the superconducting coil is heated to a first target temperature by heat generation of the conducting wire,
The superconducting magnet according to claim 1, wherein after completion of excitation of the superconducting coil, heating is canceled and the superconducting coil is cooled to a second target temperature lower than the first target temperature. Device. 3. The superconducting magnet device according to claim 2, wherein after completion of excitation of the superconducting coil, heating is stopped and the energy of the conductive wire is consumed. A superconducting coil wound with superconducting wire,
a power source that supplies current to the superconducting coil;
a conducting wire wound around the superconducting coil via an insulating material;
means for cooling the superconducting coil;
a heat generating means for causing the superconducting wire or the conducting wire to generate heat;
consuming means for consuming the energy stored in the conductive wire,
The conductive wire is composed of a first conductive wire and a second conductive wire arranged in parallel and is wound around the superconducting coil,
When heating the superconducting coil, one end of the first conducting wire and one end of the second conducting wire are short-circuited, and the other end of the first conducting wire and the other end of the second conducting wire are connected to each other by the heating means. connected to a current source for a conductor, and current is applied to the first conductor and the second conductor in which phases are different from each other by 180°,
A superconducting magnet device, wherein the other end of the first conducting wire and the other end of the second conducting wire are short-circuited during steady operation of the superconducting coil. The superconducting magnet device according to any one of claims 1 to 4, wherein the conductive wire has a cross-sectional area that differs depending on its position . A magnetocaloric material is added to the resin used for the conductive wire, the superconducting wire, or the superconducting coil,
6. The superconducting magnet device according to claim 1, wherein the superconducting coil is heated by heat generated by the magnetocaloric material.

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