JP2000182821A - Superconducting magnet and its precooling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable sharp reduction of precooling time, without increasing cooling capacity and the number of refrigerators and restraining infiltrating heat in a state of stationary operation, and realize high performance and superior handleability, in a refrigerator directly cooled type superconducting magnet. SOLUTION: This magnet comprises a superconducting coil 1, a radiation shield 2 surrounding the superconducting coil 1, a vacuum vessel 3 surrounding the radiation shield 2 and a refrigerator 4 which is attached to the vacuum vessel 3 and cools the superconducting coil 1 and the radiation shield 2. In this case, a thermal contact mechanism 7 for precooling, with which the radiation shield 2 is thermally brought into contact with the superconducting coil 1 at primary cooling time of the superconducting coil 1, is installed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting magnet, and more particularly to an improvement in a refrigerator directly cooled type superconducting magnet.

[0002]

2. Description of the Related Art Generally, a superconducting coil of a superconducting magnet is cooled by immersion cooling in which the superconducting coil is immersed in a refrigerant and cooled by the latent heat of evaporation of the refrigerant, or direct cooling of a refrigerator.

FIG. 23 is a longitudinal sectional view of a conventional refrigerator directly cooled superconducting magnet described in JP-A-8-78737 and JP-A-6-132567. In FIG. 1, reference numeral 1 denotes a superconducting coil formed by winding a superconducting wire, the outside of which is surrounded by a radiation shield 2, and the radiation shield 2 is further surrounded by a vacuum vessel 3. A refrigerator 4 is mounted on the vacuum vessel 3. The superconducting coil 1 is thermally connected to a low-temperature stage 4 a of the refrigerator 4 via a heat conducting member 5, and a high-temperature stage 4 b is connected to a radiation shield. 2 and are cooled to about 5K and 80K, respectively. The superconducting coil 1 is supported by the heat insulating support member 6 from the vacuum vessel 3 or the radiation shield 2. As a material of the heat insulating support member 6, a titanium alloy or a glass fiber reinforced plastic (GFRP) is generally used.

As described above, since the superconducting magnet of the refrigerator directly cooled type does not use liquid helium, it is excellent in handleability, but the capacity of the 4.2K refrigerator is about 1 at present.
Since it is about W, it is applied to a relatively small superconducting magnet having a small heat capacity.

Next, the operation of the superconducting magnet will be described.

After evacuating the inside of the vacuum vessel 3 to a predetermined value,
The refrigerator 4 is operated to cool the radiation shield 2 by the high-temperature side stage 4b and to cool the superconducting coil 1 by heat conduction through the heat conduction member 5 by the low-temperature side stage 4a. Here, the superconducting coil 1 has a predetermined temperature, for example, about 5K.
This process of cooling to the temperature is called pre-cooling.

[0007] The superconducting coil 1 cooled to about 5K has no electric resistance, that is, a so-called superconducting state. Therefore, a current is supplied to the superconducting coil 1 from an external excitation power supply (not shown) to generate a required magnetic field. During normal operation, the superconducting coil 1 has no electric resistance, and therefore does not itself generate heat due to Joule heat even when a current flows. However, there is heat intrusion into the superconducting coil 1 from outside due to convection, conduction, and radiation.

[0008]

However, since the above-described refrigerator direct cooling type superconducting magnet does not use liquid helium, there is no need for operations such as liquid injection and the like, and the superconducting magnet is excellent in handleability. Determined by the capacity of the machine 4.

For this reason, when the large superconducting coil 1 having a large heat capacity is cooled only by the refrigerator 4, there is a problem that a very long time is required for so-called pre-cooling for cooling from room temperature to extremely low temperature. That is, when the superconducting coil 1 in the steady state is at a very low temperature, that is, in a superconducting state, the amount of heat penetrating into the low-temperature side stage 4a of the refrigerator 4 (heat load) is generally as small as 1 W or less and sufficiently frozen. Is a value that can be cooled by the machine 4,
With the cooling capacity of 1 W, it takes several days to several weeks to cool to about 5K.

The high-temperature stage 4b of the refrigerator 7 has a cooling capacity of several tens of watts from room temperature to about 50K. In the pre-cooling process, the radiation shield 2 having a small heat capacity becomes lower in temperature than the superconducting coil 1 more quickly. Contrary to the steady state, superconducting coil 1 is cooled by radiation by radiation shield 2.
However, the outer surface of the superconducting coil 1 is generally provided with a multilayer heat insulating material in order to suppress heat intrusion due to radiation, the cooling effect by radiation is extremely small, and the high temperature side stage 4b having a large cooling capacity up to around 50K. Cannot be used effectively, and as a result, there is a problem that the pre-cooling time becomes long.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and a high-performance, low-cost superconducting magnet capable of suppressing heat intrusion in a steady state and shortening a pre-cooling time is provided. The purpose is to provide.

Another object of the present invention is to provide a method for pre-cooling a superconducting magnet which can significantly reduce the pre-cooling time.

[0013]

According to the present invention, a superconducting coil, a radiation shield surrounding the superconducting coil, a vacuum vessel surrounding the radiation shield, a superconducting coil attached to the vacuum vessel, A superconducting magnet including a refrigerator that cools a radiation shield, the superconducting magnet including a pre-cooling thermal contact mechanism that thermally contacts the radiation shield and the superconducting coil during initial cooling of the superconducting coil.

With such a superconducting magnet, the radiation shield and the superconducting coil are brought into thermal contact with each other during pre-cooling. Cooling at the same time to shorten the pre-cooling time. In particular, the specific heat of copper, which is the main material of the superconducting coil, decreases as the temperature decreases, and is about 1/4 at 50K and 1/5 at 20K at room temperature.
It becomes 1/4000 at 0 and 4K. Therefore, the time required for cooling from room temperature where the specific heat is large to 50K can be significantly reduced.

According to a second aspect of the present invention, in the superconducting magnet according to the first aspect, the pre-cooling thermal contact mechanism is connected to a drive unit attached to the vacuum container and a shaft of the drive unit, and is connected to the vacuum container. A pressure rod attached via a bellows and a contact that is connected to the pressure rod and pressed against a contact plate fixed to the superconducting coil at the other end are attached, and the load from the pressure rod is superconducted. It consists of an adiabatic driver for transmitting to the coil, and a thermal anchor having one end attached to the radiation shield and the other end fixed to the contact.

With such a superconducting magnet, in addition to the function and effect of the superconducting magnet according to the first aspect, at the time of initial cooling, a radiation shield is provided from the driving portion outside the vacuum vessel via the adiabatic driving body with a pressing rod from the driving portion. The contact that is thermally connected to the superconducting coil is pressed against the contact plate fixed to the superconducting coil, and the radiation shield and the superconducting coil are both
Cool to around 0K. After that, when the superconducting coil is cooled down to 5K, the pressing rod is pulled out and the connector is detached from the superconducting coil, so that the conduction heat from the superconducting coil to the radiation shield can be cut off.

According to a third aspect, in the superconducting magnet according to the second aspect, an elastic body having one end engaged with the contact and the other end attached to the radiation shield is mounted.

With such a superconducting magnet, in addition to the function and effect of the superconducting magnet according to the second aspect, by pulling out the pressing rod, the connector and the contact plate can be reliably separated by the restoring force of the elastic body. Therefore, when the superconducting coil is cooled down to 5K, the conduction heat to the radiation shield can be reliably shut off.

According to a fourth aspect, in the superconducting magnet according to the third aspect, the elastic body is a leaf spring.

With such a superconducting magnet, in addition to the function and effect of the superconducting magnet according to the second aspect, the plate spring has a larger heat conduction area and a smaller heat conduction distance than the coil spring. Can be used as a heat conductive member together with the anchor.

According to the fifth aspect, in the superconducting magnet according to the second aspect, the elastic body is narrowly fitted between the pressing rod and the heat insulating cylinder.

With such a superconducting magnet, in addition to the effects of the superconducting magnet according to the second aspect, the load applied to the contact surface between the contact and the contact plate is a load corresponding to the spring constant of the elastic body. Therefore, even if a thermal expansion difference occurs between the vacuum container, the superconducting coil, the pre-cooling thermal contact mechanism, and the like, it can be absorbed by deformation of the elastic body and pressed with a substantially constant load during cooling. Further, thermal stress generated in each member due to a difference in thermal contraction can be reduced.

According to a sixth aspect of the present invention, in the superconducting magnet according to the first aspect, the pre-cooling thermal contact mechanism includes a drive unit attached to the vacuum vessel, and a drive unit connected to a shaft of the drive unit and connected to the vacuum vessel. A movable plate provided so as to be able to move forward and backward through the bellows, and a contact which is connected to the movable plate at one end and presses against a contact plate fixed to the superconducting coil at the other end are attached. A heat-insulating driver for transmitting the load applied from the driver via the movable plate to the superconducting coil, and a thermal anchor having one end attached to a radiation shield and the other end fixed to a contact. Have been.

With such a superconducting magnet, in addition to the function and effect of the superconducting magnet according to the first aspect, at the time of initial cooling, an adiabatic drive is performed by a movable plate from a driving section fixed to a gantry attached to a vacuum vessel. A contact thermally connected to the radiation shield and the thermal anchor via the body is pressed against a contact plate fixed to the superconducting coil to cool both the radiation shield and the superconducting coil to around 50K. After that, when the superconducting coil is cooled down to 5K, the movable plate is raised to separate the contact from the superconducting coil, so that the heat conduction from the superconducting coil to the radiation shield can be cut off.

According to a seventh aspect of the present invention, in the superconducting magnet according to the sixth aspect, the elastic body is sandwiched between at least one of the shaft of the drive unit and the movable plate, or at least one of the movable plate and the adiabatic drive unit.

With such a superconducting magnet, in addition to the function and effect of the superconducting magnet according to claim 6, the load applied to the contact surface between the contact and the contact plate is a load corresponding to the spring constant of the elastic body. Therefore, even if a thermal expansion difference occurs between the vacuum vessel, the superconducting coil, the pre-cooling thermal contact mechanism, and the like, it can be absorbed by deformation of the elastic body and pressed with a substantially constant load during cooling. Further, thermal stress generated in each member due to a difference in thermal contraction can be reduced.

According to an eighth aspect of the present invention, in the superconducting magnet according to the first aspect, the pre-cooling thermal contact mechanism is connected to the drive unit attached to the radiation shield, and is fixed to the superconducting coil. It is composed of a contact pressed against the contact plate and a thermal anchor having one end attached to the contact and the other end fixed to a radiation shield.

With such a superconducting magnet, in addition to the functions and effects of the superconducting magnet according to the first aspect, since the drive unit is attached to the radiation shield, there is no structure penetrating the vacuum vessel, so that a mechanism is provided. Can also be easier,
Since the amount of heat entering from the room temperature portion to the radiation shield can be reduced, the heat insulation performance is improved.

According to a ninth aspect of the present invention, in the superconducting magnet according to any one of the second, sixth and eighth aspects, the driving unit includes a motor and a conversion unit that converts rotation of the motor into linear motion. It is configured.

With such a superconducting magnet, in addition to the function and effect of the superconducting magnet according to any one of claims 2, 6 and 8, the use of a motor as a driving source makes it possible to reduce the cost and the structure. Can be easy.

According to the tenth aspect, in the superconducting magnet according to the eighth aspect, the driving section is composed of a piezoelectric element.

With such a superconducting magnet, in addition to the functions and effects of the superconducting magnet according to claim 8, the contact is pressed against the superconducting coil by the piezoelectric element fixed to the radiation shield, and the radiation shield and the superconducting coil are contacted. Is thermally connected to the thermal anchor via a contact, so the mechanism is simpler and the heat generation is theoretically zero than that using a motor, so it is effective to reduce the amount of heat penetration It is. In addition, since the piezoelectric element is displaced by applying a voltage, no mechanical vibration is generated, and the superconducting coil can be operated at low cost.

According to the eleventh aspect, in the superconducting magnet according to the first aspect, the precooling thermal contact mechanism is pressed against a contact plate having one end fixed to the radiation shield and the other end fixed to the superconducting coil. And a helium gas supply pipe communicating with the telescopic container and supplying helium gas from the outside to the telescopic container.

With such a superconducting magnet, in addition to the effect of the superconducting magnet according to the first aspect, helium gas is supplied to the telescopic container to expand and contract, and the contact is pressed against the contact plate. Also, there is no self-heating unlike a motor. Since the pressing force is proportional to the pressure of the helium gas, a desired pressing force can be easily obtained. Since the heat transfer from the radiation shield to the contact is based on the heat conduction of the telescopic container and the convection of the helium gas, the cooling capacity is improved.

According to a twelfth aspect of the present invention, in the superconducting magnet according to any one of the second to eleventh aspects, each contact surface between the contact plate fixed to the superconducting coil and the contactor contacting the contact plate is provided. Irregularities are formed on at least one of the contact surfaces.

With such a superconducting magnet, in addition to the effect of the superconducting magnet according to any one of the second to ninth aspects, the contact surface pressure of the projection becomes large and the contact thermal resistance becomes small. As a result, the heat removal capability is improved, and the pre-cooling time can be shortened.

According to a thirteenth aspect, in the superconducting magnet according to any one of the second to eleventh aspects, at least one of a contact plate fixed to the superconducting coil and each contact surface of the contactor. An easy fusion metal was fixed to one contact surface.

According to such a superconducting magnet, in addition to the function and effect of the superconducting magnet according to any one of claims 2 to 11, since the fusible alloy is fixed to the contact surface, the heat removal capability is achieved. And the pre-cooling time can be shortened. In other words, easy fusible metals are soft metals that are well compatible with the mating surface, and have excellent adhesion to metals. In particular, indium fusible metals have a large thermal conductivity at extremely low temperatures and have a large contact thermal resistance. Can be reduced.

According to a fourteenth aspect, in the superconducting magnet according to any one of the second to eleventh aspects, the fusible alloy fixes at least one of indium, solder, lead and tin.

With such a superconducting magnet, in addition to the function and effect of the superconducting magnet according to any one of claims 2 to 11, if, for example, indium is fixed to the contact surface, the heat removal ability is improved. Pre-cooling time can be shortened. In other words, indium has a large thermal conductivity at a very low temperature, and is soft metal and is well compatible with the mating surface, and furthermore, has excellent adhesion to the metal, so that the contact thermal resistance of the contact surface can be reduced. .

According to a fifteenth aspect, in the superconducting magnet according to any one of the second to eleventh aspects, a tapered hole is formed in the contact plate fixed to the superconducting coil, and The outer periphery was formed in a tapered shape to fit into the tapered hole.

With such a superconducting magnet, the contact surface pressure is increased by the wedge effect in addition to the effect of the superconducting magnet according to any one of claims 2 to 11.

According to a sixteenth aspect, in the superconducting magnet according to any one of the second to eleventh aspects, a hole is formed in the contact plate fixed to the superconducting coil, and the hole contacts the outer periphery of the contact. Finger contacts were fitted to engage the holes in the plate.

In such a superconducting magnet, in addition to the functions and effects of the superconducting magnet according to any one of claims 2 to 11, the contactor and the contact plate may have a finger contact on the outer periphery in addition to the bottom surface. Because it comes into contact, the contact area increases and the thermal contact resistance decreases,
The heat removal capacity is improved, and the pre-cooling time can be shortened. Further, the finger contact can follow the eccentricity between the contact and the contact plate caused by a difference in thermal expansion or the like.

According to a seventeenth aspect, in the superconducting magnet according to any one of the second to eleventh aspects, a hole is formed in the contact plate fixed to the superconducting coil, and the contact is formed on the contact plate. A plurality of slits each having a cylindrical shape to fit into the hole and having an opening at the tip were formed on the periphery thereof.

According to such a superconducting magnet, in addition to the function and effect of the superconducting magnet according to any one of claims 2 to 11, a plurality of slits are formed in the contact. The thermal contact resistance between the contact and the contact plate can be reduced as if it were constituted by a plurality of leaf springs.

According to the eighteenth aspect, in the superconducting magnet according to the seventeenth aspect, an elastic body having a diameter-enlarging function is mounted inside the cylindrical contact.

With such a superconducting magnet, in addition to the function and effect of the superconducting magnet according to the seventeenth aspect, in addition to the spring action of the contact, the expanding diameter of the elastic body acts.
The thermal contact resistance between the contact and the contact plate can be further reduced.

According to the nineteenth aspect, in the superconducting magnet according to the eighth or eleventh aspect, a contact is formed by mounting a plurality of pins on the movable plate coupled to the drive unit, and the contact is fixed to the superconducting coil. A plurality of adapters detachably fitted to the pins were attached to the fixed plate to form a contact plate, and the pins and the radiation shield, and the adapter and the superconducting coil were thermally connected directly or indirectly, respectively, with a thermal anchor.

With such a superconducting magnet, in addition to the functions and effects of the superconducting magnet according to claim 8 or 11, the contact surface between the contactor and the contact plate has a plurality of pins and an adapter detachably fitted thereto. Therefore, thermal contact resistance is small and pre-cooling can be performed efficiently.

According to the twentieth aspect, a superconducting coil, a radiation shield surrounding the superconducting coil, a vacuum vessel surrounding the radiation shield, and a cooling vessel attached to the vacuum vessel to cool the superconducting coil and the radiation shield. In a superconducting magnet provided with a refrigerator, one end is fixed to a radiation shield directly or through a heat insulator, and the other end is fixed to a contact plate pressed to a contact plate fixed to a superconducting coil. A refrigerant container, a refrigerant supply pipe communicating with the telescopic refrigerant container and supplying a refrigerant from the outside to the telescopic refrigerant container, and a refrigerant discharge pipe communicating with the telescopic refrigerant container and discharging the refrigerant from the telescopic refrigerant container. Superconducting magnet.

With such a superconducting magnet, a refrigerant such as liquid nitrogen or liquid helium is supplied to the telescopic refrigerant container to extend the telescopic refrigerant container and press the contactor against the contact plate. The superconducting coil can be cooled by the latent heat of evaporation. Therefore, the pre-cooling time can be greatly reduced as compared with pre-cooling by the refrigerator alone.

According to the twenty-first aspect, a superconducting coil, a radiation shield surrounding the superconducting coil, a vacuum vessel surrounding the radiation shield, and attached to the vacuum vessel to cool the superconducting coil and the radiation shield. In a superconducting magnet provided with a refrigerator, a superconducting coil is:
It is a superconducting magnet supported by a support member having a thermal switching function from a radiation shield.

According to a twenty-second aspect, in the superconducting magnet according to the twenty-first aspect, the support member is formed of carbon fiber reinforced plastic (CFRP).

According to the superconducting magnets of claims 21 and 22, since the superconducting coil is supported by CFRP having a thermal conductivity 100 to 10 times larger than that at 4K from room temperature to about 80K, the structure is simplified. And has a heat switch function. Therefore, the pre-cooling time can be reduced, and at 4K in a steady state, it functions as a heat insulating support.

According to the twenty-third aspect, the superconducting coil, a radiation shield surrounding the superconducting coil, a vacuum vessel surrounding the radiation shield, and attached to the vacuum vessel to cool the superconducting coil and the radiation shield. In a superconducting magnet provided with a refrigerator, a refrigerant container disposed in a radiation shield, and a refrigerant supply pipe communicating the refrigerant supply system and the refrigerant discharge system disposed outside the refrigerant container and the vacuum container, respectively. And a refrigerant discharge pipe, wherein the refrigerant container and the superconducting coil are thermally connected directly or via a heat conducting member.

With such a superconducting magnet, a superconducting coil can be precooled by supplying a refrigerant such as liquid nitrogen or liquid helium from an external refrigerant supply system to a refrigerant container thermally connected to the superconducting coil. The pre-cooling time can be greatly reduced as compared with pre-cooling by the refrigerator alone.

According to a twenty-fourth aspect, in the superconducting magnet according to the twenty-third aspect, at least two types of refrigerant containers, a refrigerant container for liquid nitrogen and a refrigerant container for liquid helium, are provided.

With such a superconducting magnet, in addition to the functions and effects of the superconducting magnet according to claim 23,
Since the two types of refrigerant containers are provided, there is no need to perform vacuum replacement of the refrigerant, and the blockage of the refrigerant supply system due to the solidification of the refrigerant is prevented, the operation is simplified, and the pre-cooling time is shortened.

According to a twenty-fifth aspect, in the superconducting magnet according to the twentieth aspect, the step of supplying a refrigerant to the telescopic refrigerant container at the time of initial cooling and the step of exhausting the refrigerant from the telescopic refrigerant container after the completion of the initial cooling are described. This is a method for pre-cooling the superconducting magnet having the above.

According to such a precooling method, the precooling can be performed up to 80K by using liquid nitrogen as a refrigerant and to 4.2K by using liquid helium, so that the precooling time is greatly reduced.

According to a twenty-sixth aspect of the present invention, the superconducting magnet according to the twenty-third aspect has a step of supplying a refrigerant to the refrigerant container at the time of initial cooling and a step of exhausting the refrigerant from the refrigerant container after the completion of the initial cooling. Pre-cooling method.

Even in such a pre-cooling method, the pre-cooling can be performed up to 80K by using liquid nitrogen as a refrigerant and up to 4.2K when liquid helium is used, so that the pre-cooling time is greatly reduced.

According to Claim 27, Claims 1, 20, and 2
24. In the superconducting magnet according to 1 or 23, the superconducting coil is held in the sealed container with a gap provided, and the cooling medium is caused to convect in the gap between the superconducting coil and the sealed container.

With such a superconducting magnet, in addition to the function and effect of the superconducting magnet according to claim 1, heat conduction between the coil windings is small and a part of the coil is cooled. However, even a superconducting coil having a structure that is difficult to cool as a whole is well cooled.

According to Claim 28, Claims 1, 20, and 2
24. In the superconducting magnet according to 1 or 23, a regenerator material is wound into a gap between the superconducting wires of the superconducting coil.

With such a superconducting magnet, in addition to the effect of the superconducting magnet according to claim 1, 20, 21 or 23, the current flowing through the superconducting coil can be increased / decreased at a high speed, and the superconducting coil can operate in a superconducting state. Breakage can be reduced and reliability can be improved.

According to claim 29, claims 1, 20, 2
23. The superconducting magnet according to 1 or 23, wherein the regenerator material pack is wound around the superconducting coil.

With such a superconducting magnet, in addition to the functions and effects of the superconducting magnet according to the present invention, the current flowing through the superconducting coil can be increased or decreased at a high speed, and the superconducting coil can operate in a superconducting state. Breakage can be reduced and reliability can be improved.

According to Claim 30, Claims 1, 20, and 2
23. The superconducting magnet according to 1 or 23, wherein a strip-shaped regenerator material pack is provided on the surface of the superconducting coil.

With such a superconducting magnet, in addition to the functions and effects of the superconducting magnet described in claim 1, 20, 21 or 23, the energizing current of the superconducting coil can be increased or decreased at a high speed, and the superconducting coil has a superconducting state. Breakage can be reduced and reliability can be improved.

According to claim 31, claims 1, 20, 2
23. The superconducting magnet according to 1 or 23, wherein a refrigerator having a larger capacity than the refrigerator is thermally detachably provided to the superconducting coil, and the refrigerator having a large capacity is thermally connected to the superconducting coil during initial cooling. When cooled to a predetermined temperature, the refrigerator having a large capacity is thermally cut off.

With such a superconducting magnet, in addition to the function and effect of the superconducting magnet according to claim 1, a refrigerator having a large capacity is provided so as to be thermally detachable from the superconducting coil. Therefore, when the cooling device is continuously cooled depending on the use or the purpose of use in a place where the installation place is narrow, only one refrigerator having a small capacity is required, the occupied area is reduced, and the handling can be facilitated. There are advantages such as.

According to Claim 32, Claims 1, 20, and 2
24. In the superconducting magnet according to 1 or 23, a sheet having high thermal conductivity is wound between the superconducting wires of the superconducting coil.

With such a superconducting magnet, in addition to the function and effect of the superconducting magnet according to claim 1, the amount of heat transferred to the refrigerator can be increased, and heat can be removed by disturbance of the superconducting coil. And cooling rate performance can be improved.

According to Claim 33, Claims 1, 20, and 2
24. In the superconducting magnet according to 1 or 23, one or both of a plurality of openings and rectifying ribs are formed in the winding frame of the superconducting coil.

With such a superconducting magnet, the cooling effect can be enhanced in addition to the effect of the superconducting magnet according to claim 1, 20, 21 or 23. The turbulent flow is likely to occur in a portion having a large amount, the flow resistance increases, and imbalance is eliminated.

[0078]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a superconducting magnet according to the present invention, and FIG. 2 is a sectional view showing an example of a pre-cooling thermal contact mechanism.

The superconducting coil 1 is formed by winding a superconducting wire. This superconducting coil 1 has a radiation shield 2
The radiation shield 2 is surrounded by a vacuum vessel 3. Vacuum container 3
Is provided with a refrigerator 4. The refrigerator 4 is connected to a low-temperature stage 4a. The superconducting coil 1 is thermally connected to the low-temperature stage 4a via the heat conducting member 5, and the radiation shield 2 is thermally connected to the high-temperature stage 4b. The temperature is cooled down to about 5K, and the radiation shield 2 and the superconducting coil 1 are cooled down to about 80K at substantially the same temperature by the high temperature side stage 4b.

The superconducting coil 1 is provided with a heat insulating support 6
a is supported from the radiation shield 2, and the radiation shield 2 is supported from the vacuum vessel 3 by the heat insulating support 6 b.

A pre-cooling heat connection mechanism 7 is provided between the radiation shield 2 and the superconducting coil 1. The pre-cooling heat connection mechanism 7 brings the radiation shield 2 and the superconducting coil 1 into thermal contact during the initial cooling of the superconducting coil 1, and the configuration thereof will be described with reference to FIG.

A drive unit 9 is attached to the vacuum vessel 3 via a stand 8, and a pressing rod 11 is connected to a shaft 9 a of the drive unit 9. The other end of the pressing rod 11 is attached to the vacuum container 3 via a bellows 10 for vacuum sealing so as to be able to expand and contract.

The lower end of the pressing rod 11 is engaged with the adiabatic driving body 12 via the elastic body 13, and a contact 14 is attached to the lower end of the adiabatic driving body 12. here,
As a material of the adiabatic driving body 12, for example, glass fiber reinforced plastic (GFRP), carbon fiber reinforced plastic (CFRP), ceramics and the like are preferable. As the elastic body 13, a coil spring may be used.
A disc spring having a large spring constant is more suitable.

One end of a thermal anchor 15 is fixed to the contact 14, and the other end of the thermal anchor 15 is attached to the radiation shield 2. Also, this contact 1
4 is engaged with a leaf spring 16 fixed to the radiation shield 2. The leaf spring 16 always keeps the contactor 14 in contact with the contact plate 1.
7 is applied. The thermal anchor 15 uses, for example, pure aluminum having a purity of 99.99% or more, and the contact 14 uses, for example, oxygen-free copper.

On the other hand, a contact plate 17 is fixed to the superconducting coil 1 so as to face the contact 14. As shown in FIG. 3, unevenness 17a is formed on at least one of the contact surfaces of the contact plate 17 fixed to the superconducting coil 1 and the contactor 14 that comes into contact with the contact plate 17.
The unevenness 17a may be a record-like groove, a concentric groove, a knurling process, or the like.

The contact plate 1 fixed to the superconducting coil 1
An easy fusion metal 14a is fixed to at least one of the contact surfaces of the contact 7 and the contact 14 that comes into contact therewith. The fusible alloy 14a is made of, for example, indium, solder,
Lead, tin and the like. In particular, indium 14a has a high thermal conductivity at an extremely low temperature, is soft metal, is well compatible with the mating surface, and has excellent adhesion to metal.

Next, the operation of the superconducting magnet configured as described above will be described.

The superconducting coil 1, the radiation shield 2, and the vacuum vessel 3 are usually thermally separated from each other.

At the time of initial cooling (pre-cooling), the pressing rod 11 is moved toward the superconducting coil 1 by the driving section 9 mounted on the upper portion of the vacuum vessel 3, and the pressing rod 11 is moved through the elastic body 13 and the heat insulating driving body 12. The contact 14 attached to the lower end of the adiabatic driver 12 is pressed against a contact plate 17 fixed to the superconducting coil 1.

The thermal anchor 15 is fixed to the contact 14 as described above, and the other end of the thermal anchor 15 is fixed to the radiation shield 2.
The radiation shield 2 and the superconducting coil 1 are thermally connected via the thermal anchor 15 and the contact 14 by pressing the superconducting coil 4 against the superconducting coil 1.

The thermal anchor 15 has a purity of 99.
The radiation shield 2 and the superconducting coil 1 are made of 99% or more pure aluminum and the contact 14 is made of oxygen-free copper.
Is large, and can be cooled by 20 W or more with a temperature difference of 1K.

Therefore, the radiation shield 2 and the superconducting coil 1 can be cooled to about 50K at substantially the same temperature by the high-temperature side stage 4a of the refrigerator 4.

When the temperature of the superconducting coil 1 reaches about 50K, which is the temperature reached by the high-temperature side stage 4a,
The drive unit 9 is reversely driven to release the contact between the contact 14 and the contact plate 17. After this separation, superconducting coil 1 is further cooled to about 5K by low-temperature side stage 4b of refrigerator 4. Therefore, the time required for cooling from room temperature where the specific heat is large to 50K can be significantly reduced.

The heat-insulating driving body 12 is made of glass fiber reinforced plastic (GFRP), has good heat-insulating performance, and suppresses heat conduction between the radiation shield 2 and the vacuum vessel 3 as much as possible.

Since the leaf spring 16 always exerts a force to separate the contact 14 from the contact plate 17, even if there is no mechanism for pulling out the adiabatic driving body 12 or the pressing rod 11, the contact spring 14 is reliably provided. Can be separated from the contact plate 17.

As described above, according to the first embodiment, at the time of pre-cooling, the radiation shield 2 and the superconducting coil 1 are brought into thermal contact by the pre-cooling heat connection mechanism 7, so that the cooling capacity is several tens of watts. Since the radiation shield 2 and the superconducting coil 1 are simultaneously cooled to about 50K by the large high-temperature stage 4b, the pre-cooling time can be reduced. In particular, the specific heat of copper, which is the main material of the superconducting coil 1, becomes smaller as the temperature becomes lower.
It becomes 1/4000 at 0 and 4K. Therefore, the time required for cooling from room temperature where the specific heat is large to 50K can be significantly reduced.

At the time of initial cooling, the contact 14 thermally connected to the radiation shield 2 and the thermal anchor 15 from the driving section 9 outside the vacuum vessel 3 via the heat insulating driving body 12 by the pressing rod 11 is removed. Contact plate 1 fixed to superconducting coil 1
7 and the radiation shield 2 and the superconducting coil 1 are both 5
After cooling to around 0K, the pressing rod 11 is pulled out, and the contact 14 is detached from the superconducting coil 1.
When the superconducting coil 1 is cooled down to 5K by the low-temperature side stage 4a, the conduction heat from the superconducting coil 1 to the radiation shield 2 can be cut off.

Since the plate spring 16 has a larger heat conduction area and a smaller heat conduction distance than the coil spring, it can be used together with the thermal anchor 15 as a heat conduction member.

The load applied to the contact surface between the contact element 14 and the contact plate 17 is a load corresponding to the spring constant of the elastic body 13, so that the vacuum vessel 3, the superconducting coil 1, the pre-cooling thermal contact mechanism 7, etc. Even if a thermal expansion difference occurs during the cooling, it can be absorbed by deformation of the elastic body 13 and pressed with a substantially constant load during cooling. Further, thermal stress generated in each member due to a difference in thermal contraction can be reduced.

The contact plate 1 fixed to the superconducting coil 1
Since the unevenness 17a is formed on at least one of the contact surfaces of the contact member 7 and the contact element 14 contacting the contact plate 17, the contact surface pressure of the convex portion increases, and the contact thermal resistance decreases. As a result, the heat removal ability is improved, and the pre-cooling time can be shortened.

Further, since at least one of the contact surfaces of the contact plate 17 fixed to the superconducting coil 1 and the contactor 14 which comes into contact with the contact plate 17, the easy fusion metal 14a, for example, indium 14a, is fixed. Indium 14a
Has a high thermal conductivity at cryogenic temperatures, is soft metal and is well compatible with the mating surface, and has excellent adhesion to metal, so that the contact thermal resistance of the contact surface can be reduced. Therefore, the heat removal ability is further improved, and the pre-cooling time can be shortened.

Next, a second embodiment of the present invention will be described. 1 and 2 are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 4 is a sectional view of a thermal contact mechanism for pre-cooling the superconducting magnet.

The second embodiment is different from the first embodiment shown in FIG. 2 in that the arrangement position of the bellows 10 and the contact structure between the contact 14 and the contact plate 17 are changed. Other configurations are the same as those of the first embodiment shown in FIG.

The drive unit 9 is mounted on the vacuum vessel 3 through the base 8.
Is attached. The drive unit 9 is provided with a shaft 9a which forms a part of the drive unit 9 and moves forward and backward.
The lower end of the shaft 9a is engaged with a movable plate 60 that moves forward and backward by engaging with the gantry 8 via the elastic body 13.

The movable plate 60 is connected to the adiabatic driver 12, and the lower end of the adiabatic driver 12 has the contactor 14 attached thereto. Further, the movable plate 60 is attached to the vacuum vessel 3 via a bellows 10 for vacuum tightness so as to be able to expand and contract.

One end of a thermal anchor 15 is fixed to the contact 14, and the other end of the thermal anchor 15 is attached to the radiation shield 2. A finger contact 61 is mounted on the outer periphery of the contact 14.

On the other hand, a contact plate 62 is fixed to the superconducting coil 1 so as to face the contact 14. The contact plate 62 is formed with a hole 62 a that fits into a finger contact 61 mounted on the outer periphery of the contact 14.

Next, the operation of the superconducting magnet configured as described above will be described.

Superconducting coil 1 and radiation shield 2 are usually thermally separated from each other.

At the time of initial cooling (pre-cooling), the drive unit 9 mounted on the upper portion of the vacuum vessel 3 is driven, and the drive of the drive unit 9 causes the shaft 9a to move forward and backward, in this case, the shaft 9a.
Descends. The lowering of the shaft 9a causes the movable plate 60 to move toward the superconducting coil 1 via the elastic body 13, and the contact 14 attached to the lower end of the adiabatic driver 12 connected to the movable plate 60 is Is inserted into the hole 62a of the contact plate 62 fixed to the contact plate 62. In this case, since the finger contact 61 is mounted on the outer periphery of the contact 14, the finger contact 61 is inserted into the hole 17 b of the contact plate 17, and the lower surface thereof is pressed against the bottom surface 62 b of the contact plate 62.

The thermal anchor 15 is fixed to the contact 14 as described above, and the other end of the thermal anchor 15 is fixed to the radiation shield 2.
The radiation shield 2 and the superconducting coil 1 are thermally connected via the thermal anchor 15 and the contact 14 by pressing the 4 on the superconducting coil 1 via the contact plate 62.

Therefore, the radiation shield 2 and the superconducting coil 1 can be cooled to about 50K at substantially the same temperature by the high-temperature side stage 4b of the refrigerator 4.

When the temperature of the superconducting coil 1 reaches about 50 K, which is the temperature reached by the high-temperature side stage 4b,
The drive unit 9 is reversely driven to release the contact between the contact 14 and the contact plate 62.

After this separation, superconducting coil 1 is connected to refrigerator 4
Is further cooled to about 5K by the low-temperature side stage 4a. However, the time required for cooling from room temperature, where the specific heat is large, to 50 K can be significantly reduced.

Note that the elastic body 13 may be mounted between the movable plate 60 and the adiabatic driving body 12.

As described above, according to the second embodiment, the arrangement position of the bellows 10, the contact 14 and the contact plate 1
Since the finger contact 61 is provided not only on the lower surface of the contact 14 but also on the outer periphery thereof, and the finger contact 61 makes contact with the contact plate 62, the contact area increases and the thermal contact resistance decreases. Become. Further, the finger contact 61 can follow the eccentricity of the contact 14 and the contact plate 62 caused by a difference in thermal expansion or the like, and can reliably maintain the thermal contact.

According to the second embodiment, the radiation shield 2 and the superconducting coil 1 are thermally contacted by the pre-cooling heat connection mechanism 7 during pre-cooling, as in the first embodiment. Therefore, the radiation shield 2 and the superconducting coil 1 are placed on the high-temperature side stage 4b having a large cooling capacity of several tens of watts by about 50K.
Pre-cooling time can be shortened because cooling is performed to the vicinity at the same time.
In particular, the specific heat of copper, which is the main material of the superconducting coil 1, decreases as the temperature decreases, and at 50K, the specific heat becomes about 1 /
It becomes 1/50 at 4, 20K and 1/4000 at 4K. Therefore, the time required for cooling from room temperature where the specific heat is large to 50K can be significantly reduced.

At the time of initial cooling, the contact element 1 thermally connected to the radiation shield 2 and the thermal anchor 15 by the driving section 9 outside the vacuum vessel 3 via the adiabatic driving body 12 is provided.
4 is pressed against a contact plate 62 fixed to the superconducting coil 1 to cool both the radiation shield 2 and the superconducting coil 1 to around 50 K. Then, the contact 14 is detached from the superconducting coil 1. When the superconducting coil 1 is cooled down to 5K by the side stage 4a, conduction heat from the superconducting coil 1 to the radiation shield 2 can be cut off.

The load applied to the contact surface between the contact element 14 and the contact plate 62 is a load corresponding to the spring constant of the elastic body 13, so that the vacuum vessel 3, the superconducting coil 1, the pre-cooling thermal contact mechanism 7 Even if there is a difference in thermal expansion between them, it can be absorbed by deformation of the elastic body 13 and pressed with a substantially constant load during cooling.
Further, thermal stress generated in each member due to a difference in thermal contraction can be reduced.

The contact plate 6 fixed to the superconducting coil 1
If at least one of the contact surfaces of the contact member 2 and the contact element 14 contacting the contact plate 62 is formed with the irregularities 17a as shown in FIG. Since the resistance is reduced, the heat removal ability is improved as a result, and the pre-cooling time can be shortened.

Further, at least one of the contact surfaces of the contact plate 62 fixed to the superconducting coil 1 and the contact 14 contacting the contact plate 62, as shown in FIG. 3, an easy fusion metal 14a, for example, indium 14a. If fixed, the indium 14a has a high thermal conductivity at extremely low temperatures, is soft metal and is well compatible with the mating surface, and has excellent adhesion to the metal, so that the contact thermal resistance of the contact surface can be reduced. Can be. Therefore, the heat removal ability is further improved, and the pre-cooling time can be shortened.

Next, a modified example of the second embodiment will be described.

FIG. 5 is a cross-sectional view of the second embodiment in which the contact 14 and the contact plate 62 are transformed into a contact 70 and a contact plate 71, respectively.

The hole 71a of the contact plate 71 is formed as a tapered hole that shrinks.

Further, the outer periphery of the contact 70 is formed in a tapered shape to be fitted in the tapered hole 71a of the contact plate 71.

With such a configuration, at the time of initial cooling (pre-cooling), the shaft 9a moves forward and backward by the drive of the driving unit 9 mounted on the upper portion of the vacuum vessel 3, and the shaft 9a at this time is moved.
The contact 70 attached to the lower end of the adiabatic driving body 12 is inserted into the tapered hole 71a of the contact plate 71 fixed to the superconducting coil 1 by the lowering of a.

Accordingly, the tapered hole 71a of the contact plate 71 is formed, and the outer periphery of the contact 70 is formed in the tapered hole 7a of the contact plate 71.
1a, the contact surface pressure is increased by the wedge effect, and the thermal contact resistance is reduced. As a result, the heat removal capability is improved and the pre-cooling time can be shortened.

FIG. 6 is a cross-sectional view of the second embodiment in which the contact 14 and the contact plate 62 are transformed into another contact 72 and a contact plate 73, respectively.

The contact plate 73 has a cylindrical hole 73a.

The contact 72 is formed in a cylindrical shape that fits into the cylindrical hole 73a of the contact plate 73, and a plurality of slits 72a having an opening at the tip are formed on the periphery thereof. The thermal contact resistance between the contact 72 and the contact plate 73 is reduced as if the contact 72 were constituted by a plurality of leaf springs.

In this case, as the material of the contact 72, a copper alloy having a high tensile strength is desirable in order to exhibit a spring effect more. For example, alumina dispersion strengthened copper, silver-containing copper, beryllium copper, and the like.

Further, when an elastic body 74 having a diameter increasing function is mounted inside the cylindrical contact 72, the expanding force of the elastic body 74 acts in addition to the spring action of the contact 72.
The thermal contact resistance between the contact 72 and the contact plate 73 can be further reduced. As the elastic body 74 in this case, a C-type spring is preferable in terms of configuration.

With such a configuration, at the time of initial cooling (pre-cooling), the drive of the drive unit 9 mounted on the upper part of the vacuum vessel 3 causes the shaft 9a to move forward and backward.
The contact 72 attached to the lower end of the adiabatic driving body 12 due to the lowering of the contact hole 73 of the contact plate 73 fixed to the superconducting coil 1
3a.

Therefore, the contact plate 73 is formed with a cylindrical hole 73a, and the contact 72 is formed into a cylindrical shape that fits into the cylindrical hole 73a of the contact 73, and the distal end is opened on the periphery thereof. Since a plurality of slits 72a are formed, the contact surface pressure between the contact 72 and the contact plate 73 is increased, and the thermal contact resistance is reduced. As a result, the heat removal capability is improved, and the pre-cooling time can be shortened.

Next, a third embodiment of the present invention will be described.

FIG. 7 is a sectional view of a pre-cooling thermal contact mechanism for a superconducting magnet.

The second embodiment is different from the first embodiment shown in FIG. 2 in that the driving section 9 is attached to the radiation shield 2. Other configurations are the same as those of the first embodiment shown in FIG. 2, and therefore, the same components are denoted by the same reference characters and description thereof will be omitted.

The driving unit 9 includes a motor 18 that rotates and
A conversion unit 19 converts the rotational motion of the motor 18 into a linear motion, and is attached to the radiation shield 2. A contact 14 is attached to the shaft 9 a of the drive unit 9, and one end of a thermal anchor 15 attached to the radiation shield 2 is fixed to the contact 14.

On the other hand, a contact plate 17 facing the contact 14 is fixed to the superconducting coil 1.

Next, the operation of the superconducting magnet configured as described above will be described.

At the time of initial cooling (pre-cooling), the radiation shield 2
The contact 14 is moved to the superconducting coil 1 side by the driving unit 9 attached to the contact plate 1 fixed to the superconducting coil 1.
Press on 7.

The thermal anchor 15 is fixed to the contact 14, and the other end of the thermal anchor 15 is fixed to the radiation shield 2, so that when the contact 14 is pressed against the superconducting coil 1, the radiation The shield 2 and the superconducting coil 1 are thermally connected via a thermal anchor 15 and a contact 14.

When the temperature of the superconducting coil 1 reaches about 50 K, which is the temperature reached by the high-temperature side stage 4b, the driving section 9 is reversely driven, and the contact between the contact 14 and the contact plate 17 is released. After this separation, superconducting coil 1 is further cooled to about 5K by low-temperature side stage 4a of refrigerator 4.

Therefore, the time required for cooling from room temperature, where the specific heat is large, to 50K can be greatly reduced.

As described above, according to the third embodiment, since the drive unit 9 is attached to the radiation shield 2, in addition to the effects of the first embodiment, the drive unit 9 penetrates through the vacuum vessel 3. Since there are no structures, the mechanism can be simplified, the amount of heat that enters the radiation shield 2 from the room temperature can be reduced, and the heat insulation performance can be improved.

Further, in addition to the functions and effects of the first embodiment, since the driving unit 9 is attached to the radiation shield 2,
Since there is no structure penetrating through the vacuum vessel 3, the mechanism can be simplified, and the amount of heat that enters the radiation shield 2 from the room temperature can be reduced, so that the heat insulation performance is improved.

Further, since the drive unit 9 is constituted by the motor 18 and the conversion unit 19 for converting the rotation of the motor 18 into a linear motion, the structure can be inexpensive and the structure can be simplified.

Here, as the motor 18, there are an electric motor, a fluid drive motor, an ultrasonic motor, and the like. In the case of a superconducting magnet which requires a high magnetic field accuracy, an ultrasonic motor using no magnetic material is suitable.

Incidentally, the third embodiment may be modified as follows.

FIG. 8 is a cross-sectional view of a pre-cooling thermal contact mechanism when a piezoelectric element 20 is used for the driving section 9 according to the third embodiment of the present invention.

One end of the piezoelectric element 20 is
1 to the radiation shield 2 and the other end to the mounting bracket 2
2 is attached to the contact 14.

With such a configuration, the radiation shield 2
The contact 14 is pressed against the superconducting coil 1 by the piezoelectric element 20 fixed to the superconducting coil 1, and the radiation shield 2 and the superconducting coil 1 are thermally connected via the thermal anchor 15 and the contact 14.

Since the mechanism is simpler and heat generation is theoretically zero compared with the drive unit 9 using the above-described motor, it is effective to reduce the amount of heat penetration.

In addition, since the piezoelectric element 20 is displaced by applying a voltage, no mechanical vibration occurs and the superconducting coil 1 can be operated stably.

Therefore, the mechanism is simpler than that using a motor, and heat generation is theoretically zero. Therefore, it is effective to reduce the amount of heat intrusion.
, The mechanical vibration does not occur, and the superconducting coil 1 can be operated at low cost.

Next, a fourth embodiment of the present invention will be described.

FIG. 9 is a sectional view of a pre-cooling thermal contact mechanism for a superconducting magnet.

This fourth embodiment is similar to the third embodiment shown in FIG.
In this embodiment, the driving unit 9 is replaced with a telescopic container 23 driven by helium gas.

The telescopic container 23 has one end fixed to the radiation shield 2 and the other end fixed to the contact 14. The telescopic container 23 is provided with a helium gas supply pipe 25 for supplying a helium gas 24 from the outside of the vacuum container 3 to the telescopic container 23.

Next, the operation of the superconducting magnet configured as described above will be described.

At the time of initial cooling (pre-cooling), helium gas 24 is supplied to the telescopic container 23 to extend the telescopic container 23,
The contact 14 is pressed against the contact plate 17. Then, heat is transferred from the radiation shield 2 to the contact 14 by the heat conduction of the telescopic container 23 and the convective heat transfer of the helium gas 24, and the superconducting coil 1 is cooled via the contact 14 and the contact plate 17.

When the temperature of the superconducting coil 1 reaches about 50 K and reaches the temperature reached by the high-temperature stage 4b, the expansion container 23
When the helium gas 24 is exhausted, the contact between the contact 14 and the contact plate 17 is released by the spring effect of the telescopic container 23. By this separation, superconducting coil 1 is further cooled to about 5K by low-temperature side stage 4a of refrigerator 4.

As described above, according to the fourth embodiment, the cooling capacity can be improved by the heat conduction of the telescopic container 23 and the convective heat transfer of the helium gas 24, and it is necessary to cool from room temperature having a large specific heat to 50K. Time can be greatly reduced.

Further, unlike the motor, it does not generate heat by itself, and can reduce the invasion heat. Since the pressing force is proportional to the pressure of the helium gas, a desired pressing force can be easily obtained.

Here, as the material of the elastic container 23, copper or aluminum having high thermal conductivity is preferable. Also, FIG.
As shown in FIG. 0, the radiation shield 2 and the contact 14 may be thermally connected by a thermal anchor 15 as in the first to third embodiments.

Next, a fifth embodiment of the present invention will be described.

FIG. 11 is a sectional view of a thermal contact mechanism for pre-cooling a superconducting magnet.

The fifth embodiment is different from the fourth embodiment shown in FIG.
In this embodiment, the contact structure between the contact 14 and the contact plate 17 is different from that of the first embodiment.

The telescopic container 23 fixed to the radiation shield 2
A plurality of pins 27 are mounted on a movable plate 26 coupled to the superconducting coil 1 to form a contact 14. On the other hand, a plurality of adapters 28 detachable from the pin 27 are mounted on a fixed plate 29 fixed to the superconducting coil 1. The contact plate 17 is configured by being mounted, and the pin 27 and the radiation shield 2 are thermally connected to the adapter 28 and the superconducting coil 1 by the thermal anchor 15, respectively.

With such a configuration, at the time of initial cooling (pre-cooling), helium gas 24 is supplied to the telescopic container 23 to extend the telescopic container 23, and the pins 27 are fitted to the adapters 28 to make thermal contact. Let it.

As a result, heat is transferred from the radiation shield 2 to the superconducting coil 1 via the thermal anchor 15, the pins 27, and the adapter 28, and the superconducting coil 1 is cooled.

As described above, according to the fifth embodiment, since the thermal contact surface is constituted by the plurality of pins 27 and the adapter 28 which is detachably fitted to the pins 27, the thermal contact surface is surely brought into surface contact. Low thermal contact resistance and efficient pre-cooling.

Although the thermal anchor 15 is fixed to each pin 27 and each adapter 28 in the fifth embodiment, the pins 27 and the adapter 28 are respectively attached to the movable plate 26 or the fixed plate 29 having good heat conduction. The movable plate 26 and the radiation shield 2, and the fixed plate 29 and the superconducting coil 1 may be thermally connected to each other by the thermal anchor 15 by soldering or brazing.

Next, a sixth embodiment of the present invention will be described.

FIG. 12 is a sectional view of a thermal contact mechanism for pre-cooling a superconducting magnet.

This sixth embodiment is similar to the fourth embodiment shown in FIG.
In this embodiment, a refrigerant such as liquid nitrogen or liquid helium is used instead of helium gas.

The expandable and contractible refrigerant container 30 has one end fixed to the radiation shield 2 and the other end fixed to the contact 14. The telescopic refrigerant container 30 includes a vacuum container 3
From the refrigerant supply system 33 installed outside the
0 is provided with a refrigerant supply pipe 31 for supplying a refrigerant such as liquid nitrogen or liquid helium, and a refrigerant discharge pipe 32 for discharging the refrigerant to an external refrigerant discharge system 34.

Further, the refrigerant discharge pipe 32 is provided with an exhaust system 35 for evacuating the inside of the telescopic refrigerant container 30.

Next, the operation of the superconducting magnet configured as described above will be described.

At the time of initial cooling (pre-cooling), the telescopic refrigerant container 3
0 to supply liquid nitrogen to extend the telescopic refrigerant container 30,
The contact 14 is pressed against the contact plate 17.

Thus, the superconducting coil 1 can be cooled by the latent heat of evaporation of the liquid nitrogen via the contactor 14 and the contact plate 17. The cooling capacity by the latent heat of evaporation is several kilowatts compared to the cooling capacity of the high-temperature side stage 4b of the refrigerator of several tens of watts. Can be shortened.

In this state, the liquid nitrogen in the telescopic refrigerant container 30 may be discharged to separate the contactor 14 and the contact plate 17 from each other. By supplying liquid helium into the telescopic refrigerant container 30, the superconducting coil 1 can be cooled to about 5K.
When cooling to the liquid helium temperature, the expansion and contraction refrigerant container 30 and the radiation shield are fixed via a heat insulating material.

After the completion of the pre-cooling, the contact 14 and the contact plate 17 are separated from each other, and the inside of the telescopic refrigerant container 30, the refrigerant supply pipe 31, and the refrigerant discharge pipe 32 is evacuated to the outside to the radiation shield 2 from the outside. 2 to superconducting coil 1
The heat of penetration into the body can be reduced.

As described above, according to the sixth embodiment, a refrigerant such as liquid nitrogen or liquid helium is supplied to the telescopic refrigerant container 30 to extend the telescopic refrigerant container 30 and the contactor 14 is brought into contact with the contact plate 17. The superconducting coil 1 can be cooled by the latent heat of evaporation of the refrigerant.

Therefore, the pre-cooling time can be greatly reduced as compared with pre-cooling by the refrigerator alone. For example, regardless of the cooling capacity of the refrigerator 4, the superconducting coil 1
Can be quickly cooled to a predetermined temperature.

The expansion / contraction refrigerant container 30 may be separately provided for liquid helium and liquid nitrogen.

In this case, there is no need to perform vacuum replacement of the refrigerant, and it is possible to prevent the refrigerant supply system from being clogged by solidification of the refrigerant (for example, when liquid nitrogen and liquid helium are used, liquid nitrogen is solidified). The operation is simplified, and the pre-cooling time is shortened.

Next, a seventh embodiment of the present invention will be described.

FIG. 13 is a sectional view of a superconducting magnet.

In the seventh embodiment, the supporting structure of superconducting coil 1 shown in FIG. 23 is changed. Other configurations are the same as those of the conventional superconducting magnet shown in FIG. 23, and thus the same components are denoted by the same reference characters and description thereof will be omitted.

The radiation shield 2 is supported from the vacuum vessel 3 by a heat insulating support member 6, and the superconducting coil 1 is independently supported by the radiation shield 2 by a heat insulating support member 36. Here, the heat insulating support member 36 is made of carbon fiber reinforced plastic (hereinafter, referred to as CFRP).

Since the thermal conductivity of this CFRP from room temperature to about 80K is 100 to 10 times larger than that at 4K, the superconducting coil 1 is cooled by the radiation shield 2 during precooling.

On the other hand, at the time of 4K operation, the heat conductivity of the heat insulating support member 36 made of CFRP is small and has a so-called thermal switching function, so that heat entering the superconducting coil 1 from the radiation shield 2 can be suppressed.

Therefore, the structure of the superconducting coil 1 can be simplified.
The cooling time can be reduced, and at 5K in a steady state, it functions as a heat insulating support.

Next, an eighth embodiment of the present invention will be described.

FIG. 14 is a sectional view of a superconducting magnet.

Since the basic configuration of the eighth embodiment is the same as that of the conventional superconducting magnet shown in FIG. 23, the same elements are denoted by the same reference numerals and description thereof will be omitted.

The refrigerant container 37 is provided in the radiation shield 2 so as to be thermally connected to the superconducting coil 1. The refrigerant container 37 has a refrigerant supply pipe 31 for supplying a refrigerant such as liquid nitrogen or liquid helium from a refrigerant supply system 33 provided outside the vacuum container 3 to the refrigerant container 37, and a refrigerant supply pipe 31 for supplying an external refrigerant discharge system 34. And a refrigerant discharge pipe 32 for discharging the air.

Furthermore, the refrigerant discharge pipe 32 has a refrigerant container 3
An exhaust system 35 for replacing the inside of the chamber 7 with a vacuum is provided.

Next, the operation of the superconducting magnet configured as described above will be described.

At the time of initial cooling (pre-cooling), liquid nitrogen is supplied to the refrigerant container 37, and the superconducting coil 1 is cooled by the latent heat of evaporation of the liquid nitrogen in the refrigerant container 37.

The cooling capacity by the latent heat of evaporation is several kW compared to the cooling capacity of the high-temperature side stage 4b of the refrigerator of several tens of watts.
Pre-cooling time can be greatly reduced.

Further, the superconducting coil 1 can be cooled down to 4.2K by evacuating the refrigerant container 37 by the exhaust system 35 and then supplying liquid helium into the refrigerant container 37.

After the completion of the precooling, the inside of the superconducting coil 1 can be reduced by evacuating the refrigerant container 37, the refrigerant supply pipe 31, and the refrigerant discharge pipe 32 from the outside.

As described above, according to the eighth embodiment, refrigerant container 37 thermally connected to superconducting coil 1 can be used.
Since the superconducting coil 1 can be pre-cooled by supplying a coolant such as liquid nitrogen or liquid helium from the external coolant supply system 33, the pre-cooling time can be greatly reduced as compared with pre-cooling by the refrigerator alone. Thereby, the superconducting coil 1 can be quickly cooled to a predetermined temperature in a short time of about two days without depending on the cooling capacity of the refrigerator 4.

[0208] The refrigerant container 37 may be separately provided for liquid helium and liquid nitrogen. In this case, it is not necessary to perform vacuum replacement of the refrigerant, and it is possible to prevent the refrigerant supply system from being blocked due to solidification of the refrigerant (for example, when liquid nitrogen and liquid helium are used, the liquid nitrogen is solidified). Is simplified and the pre-cooling time is shortened.

The refrigerant container 37 and the superconducting coil 1 may be thermally connected via a thermal anchor.

In each of the above embodiments, the contact 14 and the contact plate 17 in the superconducting magnet pre-cooling thermal contact mechanism shown in FIGS. 7 to 10 and FIG.
As shown in FIG. 3 above, at least one of the contact surfaces of the contactor 14 and the contact plate 17 has unevenness 1
7a may be formed, or the easy fusion metal 14a may be fixed to at least one of the contact surfaces of the contact plate 17 and the contactor 14.

The structure applied to the superconducting magnets of the first to eighth embodiments will be described below.

First, a ninth embodiment of the present invention will be described.

FIG. 15 is a sectional view of a superconducting magnet.

This superconducting magnet is applied to the superconducting magnets of the first to eighth embodiments. The superconducting coil 1 is held in a closed vessel 40 with its periphery covered with helium gas 41. The superconducting coil 1 is cooled by a helium gas 41 in which a cooling unit 42 indicated by a hatched portion in the upper part of the closed vessel 40 is cooled by a refrigerator.

The superconducting coil 1 and the closed vessel 40 are fixed with a sufficient gap therebetween, and the helium gas 41 cooled by the cooling section 42 at the upper part of the closed vessel 40 is supplied with the superconducting coil. 1, a gap 43b below the superconducting coil 1 below the gap 43a inside the
c, convection that passes through the upper gap 43d and returns to the cooling section 42 again is likely to occur.

The flow of the helium gas 41 increases the thermal conductivity between the superconducting coil 1 and the helium gas 41, thereby improving the cooling performance.

As described above, according to the ninth embodiment, the superconducting coil 1 is provided inside the sealed container 40 with the gaps 43a to 43a.
3d is provided and held, and helium gas 41 is convected in the gaps 43a to 43d between the superconducting coil 1 and the inside of the sealed container 40, so that the heat conduction between the coil windings of the superconducting coil 1 is small and a part of the coil is removed. The superconducting coil 1 having a structure in which the whole is hardly cooled even when cooled can be cooled well. That is,
A superconducting coil, such as a non-impregnated coil, which has a small heat conduction between coil windings and has a structure in which the whole is hardly cooled even when a part of the coil is cooled, can be cooled well.

The effect is particularly large at the time of initial cooling, and cooling can be performed in a short time. By dividing the coil vertically, the contact area between the helium gas 41 and the superconducting coil 1 increases, and the effect is further enhanced.

Further, since the specific heat of the helium gas 41 is large at about 4K, it has the same effect as the heat storage material of the ninth embodiment described below.

Most of the cooling time is from room temperature to 10
Since the cooling time is about 0K, the helium gas 41, whose heat capacity is extremely small in this temperature range, and has an extremely large specific heat in the vicinity of 4K, does not burden the cooling during the initial cooling and does not conduct heat. The effect of improving the rate can be exhibited, and at low temperatures, the effect as a cold storage material is exhibited.

Next, a tenth embodiment of the present invention will be described.

FIG. 16 is a main enlarged view of the cut piece shape of the superconducting magnet.

The superconducting coil 1 is obtained by winding a sheet-like cold storage material 45 between the layers during the step of winding the superconducting wire 44 in a coil shape.

The regenerative material 45 is formed of, for example, Er3Ni (erbium nickel). The material wound between the layers may be a tape-like material, or may be wound not on the layers but on a superconducting wire. This cold storage material 45 is E
In addition to r3Ni, for example, ErNi2, Er0.4Dy
0.6Ni2, ErNi, Er0.2Dy0.8Ni
2, DyNi2, Pb, Gd0.5Er0.5Rh, etc. are effective.

On the other hand, FIG. 17 is a main enlarged view of a cut piece shape of a superconducting magnet, and shows an example in which a string-like cold storage material 46 is wound into a gap between superconducting wires.

This cold storage material 46 is also made of, for example, Er3
Ni, ErNi2, Er0.4Dy0.6Ni2, Er
Ni, Er0.2Dy0.8Ni2, DyNi2, P
b, Gd0.5Er0.5Rh and the like are effective.

With such a configuration, superconducting coil 1
The superconducting coil 1 generates heat when increasing or decreasing the conduction current to the superconducting coil 1, and the superconducting state of the superconducting coil 1 is broken even if the conduction current is increased or decreased at a speed higher than a certain speed. Is gone.

The fact that the current supplied to the superconducting coil 1 can be increased or decreased at a high speed allows the superconducting coil 1 to be used in a wider range of use and lower operating costs.

As described above, according to the tenth embodiment, since the cold storage material 45 or 46 is wound in the gap between the superconducting wires of the superconducting coil 1, the current flowing through the superconducting coil 1 can be increased or decreased at a high speed. The state in which the superconducting coil 1 is broken in the superconducting state can be reduced, and the reliability can be improved.

That is, in the example of the superconducting coil 1 manufactured by the conventional method, the limit is 10 A / s, but in the superconducting coil 1 of the present invention, the flowing current can be increased or decreased about three times faster. When used at the same increasing and decreasing rate of the current, the superconducting state of the superconducting coil 1 can be reduced until it can be said that there is almost no breakage state, and the reliability as a superconducting magnet can be greatly improved.

Next, an eleventh embodiment of the present invention will be described.

FIG. 18 is an enlarged view of a main part of the superconducting magnet.

This superconducting magnet is composed of a superconducting coil 1
In addition, since the cool storage material pack 47 is wound, the same effects as those of the ninth embodiment can be obtained, and the construction is easy.

Next, a twelfth embodiment of the present invention will be described.

FIG. 19 is an enlarged view of a main part of the superconducting magnet.

This superconducting magnet is composed of a superconducting coil 1
Of the superconducting coil 1 can be increased / decreased at a high speed as in the tenth embodiment, and the state of the superconducting coil 1 in which the superconducting state is broken can be reduced. , Reliability can be improved, and its construction is easy.

This superconducting magnet is similar to that shown in FIG.
Superconducting magnet 1 as well as the superconducting magnet shown in FIG.
Although the example in which the cold storage material 48 is attached to the outside is shown, it is not limited to this, and it is also possible to attach the inside to the inside.

Since the cold storage material pack 47 shown in FIG. 18 is adhered in the same direction as the superconducting wire, if there is a gap between the cold storage material packs 47, the effect of the present invention on the wire in the gap is Although it is low, if it is a strip-shaped cold storage material 48 like the superconducting magnet of the present invention, it can be stuck to the superconducting wire in a substantially vertical direction, and even if there is a gap between the cold storage materials, the effect is large.

Next, a thirteenth embodiment of the present invention will be described.

FIG. 20 is an enlarged view of a main part of the superconducting magnet.

This superconducting magnet is provided with a refrigerating machine 49 having a larger capacity than the refrigerating machine 4 detachably, separately from the refrigerating machine 4 for steady cooling.

The large-capacity refrigerator 49 can be installed and operated only at the time of initial cooling, and can be removed or thermally cut when cooled to about 40 to 50K. In this example, a heat conducting plate 51 made of copper is directly attached to the high-temperature side stage 50 of the refrigerator 49 and comes into contact with the heat conducting plate 52 attached to the superconducting coil 1.

As described above, according to the thirteenth embodiment,
A refrigerator 49 having a larger capacity than the refrigerator 4 for steady-state cooling is thermally detachably provided to the superconducting coil 1, and the refrigerator 49 having a large capacity is thermally connected to the superconducting coil 1 during initial cooling. Since the large-capacity refrigerator 49 is thermally cut off when cooled to a predetermined temperature, the small-capacity refrigerator is required to be continuously cooled depending on the use in a narrow installation place or the degree of the purpose of use. 4 only needs to be one unit, the occupied area is reduced, and handling is easy.
Further, there are advantages such as lower maintenance costs.

When the cooling and heating are frequently repeated or the initial cooling time is required to be shortened, the cooling can be performed more quickly by operating the large-capacity refrigerator 49 for precooling.

Next, a fourteenth embodiment of the present invention will be described.

FIG. 21 is a main enlarged view of a cut piece shape of the superconducting magnet.

This superconducting magnet is composed of a superconducting coil 1
The aluminum sheet 53 is wound between the layers during the step of winding the superconducting wire 44 in a coil shape.

Aluminum has a high thermal conductivity.
The amount of heat transfer to the refrigerator can be increased, the heat removal due to disturbance of the superconducting coil 1 and the cooling speed performance can be improved, and the effect can be doubled if applied to the superconducting magnet shown in FIG.

In addition to the aluminum sheet 53, indium, lead, and an indium-lead alloy used as low-temperature solder are also effective.

As described above, according to the fourteenth embodiment, since the aluminum sheet 53 having a high thermal conductivity is wound between the superconducting wires of the superconducting coil 1, the amount of heat transfer to the refrigerator can be increased. Heat removal due to disturbance of the superconducting coil 1 and cooling speed performance can be improved.

Next, a fifteenth embodiment of the present invention will be described.

FIG. 22 is a perspective view of a superconducting coil in the superconducting magnet.

The winding frame 54 of the superconducting coil 1 is provided with a plurality of holes 55. Generally, a long hole or a slit which is long in the axial direction of the superconducting coil has a higher cooling effect. In this example, since the winding frame 54 is formed as thin as possible, the diameter 56 of each hole 55 can be made sufficiently larger than the thickness 57 of the winding frame 54, and the hole 55 having a high cooling effect can be obtained.

If the diameter 56 of the hole 55 or the length of the slit is smaller than the thickness of the winding frame 54, the flow of the helium gas flowing on the surface of the winding frame 54 will not sufficiently hit the superconducting coil surface,
The effect of the hole 55 does not live sufficiently.

On the other hand, a rectifying rib 58 is spirally provided on the winding frame 54 of the superconducting coil 1.

The rectifying ribs 58 are originally intended to obtain the rectification of the refrigerant. However, if the rectifying ribs 58 cause imbalance in the flow rate between the rectifying ribs 58, the flow rate is increased. The portion becomes turbulent, and acts to increase the flow resistance and eliminate the imbalance.
Further, since the turbulent flow has a large thermal conductivity, cooling of the entire superconducting coil 1 is not impaired.

In FIG. 22, the rectifying rib 58 does not have a sufficient angle. However, by providing one rectifying rib 58 at an angle such that the winding frame 54 makes at least one round, Even if the flow rate between the rectifying ribs 58 remains unbalanced, cooling over the entire length of the superconducting coil 1 can be achieved only by cooling with helium gas during that time.

The superconducting coil 1 is sufficiently cooled in the circumferential direction by the heat conduction of its windings, but has a structure with very poor heat conduction in the axial direction. When the helium gas flows, the cooling effect increases.

Further, the gap between the winding frame 54 and the coil container is made larger than the plate thickness of the winding frame 54. This is to ensure a sufficient flow rate of the helium gas.

In this state, if a turbulence promoting mechanism is provided in the gap between the winding frame 54 and the coil container and between the rectifying ribs 58, heat transfer between the winding frame 54 and the superconducting coil 1 and the helium gas is improved, and The cooling of the coil 1 is improved, and the reliability is improved.

As described above, according to the fifteenth embodiment, since one or both of the plurality of holes 55 and the rectifying ribs 58 are formed in the winding frame 54 of the superconducting coil 1, the cooling effect is enhanced. Even if the flow rate of the refrigerant becomes unbalanced, a portion having a large flow rate becomes turbulent, the flow resistance increases, and the imbalance can be eliminated.

[0262]

As described above, according to the present invention, the pre-cooling time can be greatly reduced without increasing the cooling capacity of the refrigerator or increasing the number of refrigerators in the refrigerator directly cooled superconducting magnet. It is possible to provide a superconducting magnet having high performance and excellent handleability capable of suppressing invasion heat in a steady operation state.

Further, according to the present invention, it is possible to provide a method for pre-cooling a superconducting magnet which can greatly reduce the pre-cooling time.

Further, according to the present invention, it is possible to provide a superconducting magnet which can improve the heat conduction performance and further reduce the time required for the initial cooling.

Further, according to the present invention, it is possible to provide a superconducting magnet in which the superconducting state is not destroyed by a large heat intrusion or a sudden heat generation by improving the heat conduction performance or attaching a regenerator material having a large heat capacity.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a superconducting magnet according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing an example of a pre-cooling thermal contact mechanism according to the first embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing an example of a contact portion of the pre-cooling thermal contact mechanism according to the first embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of a pre-cooling thermal contact mechanism of a superconducting magnet according to a second embodiment of the present invention.

FIG. 5 is a sectional view showing a modification of the contactor and the contact plate according to the second embodiment of the present invention.

FIG. 6 is a sectional view showing another modification of the contact and the contact plate according to the second embodiment of the present invention.

FIG. 7 is a longitudinal sectional view of a pre-cooling thermal contact mechanism of a superconducting magnet according to a third embodiment of the present invention.

FIG. 8 is a longitudinal sectional view of a pre-cooling thermal contact mechanism when a piezoelectric element is used for a drive unit according to a third embodiment of the present invention.

FIG. 9 is a longitudinal sectional view of a pre-cooling thermal contact mechanism of a superconducting magnet according to a fourth embodiment of the present invention.

FIG. 10 is a longitudinal sectional view showing a modification of the pre-cooling thermal contact mechanism of the superconducting magnet according to the fourth embodiment of the present invention.

FIG. 11 is a longitudinal sectional view of a pre-cooling thermal contact mechanism of a superconducting magnet according to a fifth embodiment of the present invention.

FIG. 12 is a longitudinal sectional view of a pre-cooling thermal contact mechanism of a superconducting magnet according to a sixth embodiment of the present invention.

FIG. 13 is a longitudinal sectional view of a superconducting magnet according to a seventh embodiment of the present invention.

FIG. 14 is a longitudinal sectional view of a superconducting magnet according to an eighth embodiment of the present invention.

FIG. 15 is a longitudinal sectional view of a superconducting magnet according to a ninth embodiment of the present invention.

FIG. 16 is a main enlarged view of a cut piece shape of a superconducting magnet according to a tenth embodiment of the present invention.

FIG. 17 is a view showing another example of the superconducting magnet according to the tenth embodiment of the present invention.

FIG. 18 is a main enlarged view of a superconducting magnet according to an eleventh embodiment of the present invention.

FIG. 19 is a main enlarged view of a superconducting magnet according to a twelfth embodiment of the present invention.

FIG. 20 is a main perspective view of a superconducting magnet according to a thirteenth embodiment of the present invention.

FIG. 21 is a main enlarged view of a cut piece shape of a superconducting magnet according to a fourteenth embodiment of the present invention.

FIG. 22 is a perspective view of a superconducting coil in a superconducting magnet according to a fifteenth embodiment of the present invention.

FIG. 23 is a longitudinal sectional view of a conventional refrigerator supercooling magnet of direct cooling type.

[Explanation of symbols]

 1: Superconducting coil 2: Radiation shield 3: Vacuum container 4: Refrigerator 4a: Low-temperature side stage 4b: High-temperature side stage 5: Heat conducting member 6a, 6b, 36: Heat insulating support material 7: Pre-cooling thermal contact mechanism 8: Stand 9: drive unit 9a: shaft 10: bellows 11: pressing rod 12: heat insulating cylinder 13: elastic body 14: contact 14a: indium 15: thermal anchor 16: leaf spring 17: contact plate 17a: unevenness 18: motor 19: Converter 20: Piezoelectric element 21: Fixture 22: Mounting bracket 23: Telescopic container 24: Helium gas 25: Helium gas supply pipe 26: Movable plate 27: Pin 28: Adapter 29: Fixed plate 30: Telescopic refrigerant container 31: Refrigerant Supply pipe 32: Refrigerant discharge pipe 33: Refrigerant supply system 34: Refrigerant discharge system 35: Exhaust system 37: Refrigerant container 40: Closed container 41: Helium gas 42: Cold Cooling parts 43a to 43d: gaps 45, 46, 48: cold storage material 47: cold storage material pack 49: refrigerator 50: high-temperature side stage 51, 52: heat conductive plate 54: reel 55: hole 58: rectifying rib 60: movable Plate 61: finger contact 62: contact plate 62a: hole 62b: bottom surface 70: contact 71: contact plate 71a: tapered hole 72: contact 73: contact plate 73a: hole 74: elastic body

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Makoto Kyoto 2-4-4 Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture F-term in the Toshiba Keihin Works (reference) 4M114 AA02 AA17 AA20 AA22 AA31 AA40 CC03 CC12 CC13 CC16 CC18 DA02 DA07 DA09 DA10 DA12 DA51 DA54 DA55 DB62

Claims (33)

[Claims] 1. A superconducting coil, a radiation shield surrounding the superconducting coil, a vacuum vessel surrounding the radiation shield, and a refrigerator attached to the vacuum vessel and cooling the superconducting coil and the radiation shield. A superconducting magnet, comprising: a pre-cooling thermal contact mechanism for thermally contacting the radiation shield and the superconducting coil during initial cooling of the superconducting coil. 2. The pre-cooling thermal contact mechanism includes a drive unit attached to the vacuum container, and an expansion rod coupled to a shaft of the drive unit and attached to the vacuum container via a bellows. When,
A contact for pressing against a contact plate fixed to the superconducting coil is attached to the other end connected to the drawing rod, and an adiabatic driver for transmitting a load from the pressing rod to the superconducting coil. One end is attached to the radiation shield,
The superconducting magnet according to claim 1, wherein the other end is constituted by a thermal anchor fixed to the contact. 3. The superconducting magnet according to claim 2, wherein one end is engaged with the contact, and the other end is fitted with an elastic body attached to the radiation shield. 4. The superconducting magnet according to claim 3, wherein said elastic body is a leaf spring. 5. The superconducting magnet according to claim 2, wherein an elastic body is narrowly fitted between the pressing rod and the heat insulating driving body. 6. The pre-cooling thermal contact mechanism includes a drive unit attached to the vacuum vessel, and is connected to a shaft of the drive unit and moves with respect to the vacuum vessel via a bellows so as to be movable forward and backward. And a contact that has one end connected to the movable plate and the other end pressed against a contact plate fixed to the superconducting coil is attached to the movable plate. And a thermal anchor having one end attached to the radiation shield and the other end fixed to the contact. The superconducting magnet according to claim 1, wherein 7. The superconducting magnet according to claim 6, wherein an elastic body is sandwiched between at least one of the axis of the driving section and the movable plate, or between the movable plate and the adiabatic driving body. . 8. The pre-cooling thermal contact mechanism includes: a drive unit attached to the radiation shield; a contact coupled to the drive unit and pressed by a contact plate fixed to the superconducting coil; 2. A superconducting magnet according to claim 1, wherein said superconducting magnet is constituted by a thermal anchor fixed to said radiation shield at the other end. 9. The apparatus according to claim 2, wherein the drive unit includes a motor and a conversion unit that converts the rotation of the motor into a linear motion. Superconducting magnet. 10. The superconducting magnet according to claim 8, wherein the driving section is made of a piezoelectric element. 11. The pre-cooling thermal contact mechanism has one end fixed to the radiation shield and the other end fixed to a contact pressed against a contact plate fixed to the superconducting coil. 2. The superconducting magnet according to claim 1, comprising a container and a helium gas supply pipe communicating with the telescopic container and supplying helium gas to the telescopic container from the outside. 12. A method according to claim 1, wherein at least one of contact surfaces of a contact plate fixed to said superconducting coil and a contact contacting said contact plate has irregularities. Item 12. The superconducting magnet according to any one of items 2 to 11. 13. An easy fusion metal is fixed to at least one of contact surfaces between the contact plate fixed to the superconducting coil and the contactor. Item 12. The superconducting magnet according to any one of items 11 to 12. 14. The superconducting magnet according to claim 2, wherein the fusible alloy has at least one of indium, solder, lead, and tin fixed thereto. 15. The contact plate fixed to the superconducting coil has a tapered hole formed therein, and an outer periphery of the contact is formed in a tapered shape to be fitted in the tapered hole. Any one of claims 2 to 11
Superconducting magnet according to the item. 16. The contact plate fixed to the superconducting coil, wherein a hole is formed, and a finger contact that engages with the hole of the contact plate is mounted on an outer periphery of the contact. The superconducting magnet according to any one of claims 11 to 11. 17. A hole is formed in the contact plate fixed to the superconducting coil, and the contact is formed in a cylindrical shape to be fitted in the hole of the contact plate, and a distal end portion is opened on a periphery thereof. The superconducting magnet according to any one of claims 2 to 11, wherein a plurality of slits are formed. 18. The superconducting magnet according to claim 17, wherein an elastic body having a diameter increasing function is mounted inside the cylindrical contact. 19. A plurality of pins are mounted on a movable plate coupled to the driving unit to form a contact, and a plurality of pins are detachably fitted to the pins on a fixed plate fixed to the superconducting coil. The contact plate is configured by mounting an adapter, and the pin and the radiation shield, and the adapter and the superconducting coil are thermally connected directly or indirectly by the thermal anchor, respectively. Superconducting magnet. 20. A superconducting coil, a radiation shield surrounding the superconducting coil, a vacuum vessel surrounding the radiation shield, and a refrigerator attached to the vacuum vessel and cooling the superconducting coil and the radiation shield. A superconducting magnet comprising: a telescopic refrigerant having one end fixed to the radiation shield directly or via a heat insulator, and the other end fixed to a contact pressed against a contact plate fixed to the superconducting coil. A container, a refrigerant supply pipe communicating with the telescopic refrigerant container and supplying a refrigerant from the outside to the telescopic refrigerant container, and a refrigerant discharge pipe communicating with the telescopic refrigerant container and discharging the refrigerant from the telescopic refrigerant container. A superconducting magnet, comprising: 21. A superconducting coil, a radiation shield surrounding the superconducting coil, a vacuum vessel surrounding the radiation shield, and a refrigerator attached to the vacuum vessel and cooling the superconducting coil and the radiation shield. A superconducting magnet comprising: a superconducting magnet, wherein the superconducting coil is supported by a support member having a thermal switching function from the radiation shield. 22. The superconducting magnet according to claim 21, wherein said support member is formed of carbon fiber reinforced plastic. 23. A superconducting coil, a radiation shield surrounding the superconducting coil, a vacuum vessel surrounding the radiation shield, and a refrigerator attached to the vacuum vessel and cooling the superconducting coil and the radiation shield. A superconducting magnet comprising: a refrigerant container disposed in the radiation shield; a refrigerant supply pipe for communicating the refrigerant container and a refrigerant supply system and a refrigerant discharge system disposed outside the vacuum container; and A superconducting magnet comprising a refrigerant discharge pipe, wherein the refrigerant container and the superconducting coil are thermally connected directly or via a heat conducting member. 24. The superconducting magnet according to claim 23, wherein at least two kinds of refrigerant containers are disposed, a refrigerant container for liquid nitrogen and a refrigerant container for liquid helium. 25. The superconducting magnet according to claim 20, comprising: a step of supplying a refrigerant to the telescopic refrigerant container at the time of initial cooling; and a step of exhausting the refrigerant from the telescopic refrigerant container after completion of the cooling. Pre-cooling method for superconducting magnets. 26. The superconducting magnet according to claim 23, comprising: a step of supplying a refrigerant to the refrigerant container at the time of initial cooling; and a step of exhausting the refrigerant from the refrigerant container after the completion of the cooling. Pre-cooling method for superconducting magnet. 27. The superconducting coil is held in a sealed container with a gap provided therebetween, and a cooling medium is convected in a gap between the superconducting coil and the sealed container. Superconducting magnet as described. 28. A cooling material is wound in a gap between superconducting wires of said superconducting coil.
The superconducting magnet according to any one of 20, 21, and 23. 29. The superconducting magnet according to claim 1, wherein a regenerative material pack is wound around the superconducting coil. 30. A strip-shaped regenerator material pack is provided on the surface of the superconducting coil.
The superconducting magnet according to any one of 0, 21 and 23. 31. A refrigerator having a larger capacity than the refrigerator is thermally detachably provided to the superconducting coil, and the refrigerator having a large capacity is thermally connected to the superconducting coil during initial cooling. The superconducting magnet according to any one of claims 1, 20, 21 and 23, wherein the refrigerator having a large capacity is thermally cut off when cooled to a predetermined temperature. 32. The superconducting magnet according to claim 1, wherein a sheet having a high thermal conductivity is wound between the superconducting wires of the superconducting coil. 33. The superconducting coil according to claim 1, wherein one or both of a plurality of openings and rectifying ribs are formed in the winding frame of the superconducting coil. Superconducting magnet as described.