JP2003059713A - Superconductive magnet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a superconductive magnet which is reduced in size and capable of decreasing the evaporation loss of liquid helium. SOLUTION: A coil unit helium tank 2a where a superconductive coil 1 is housed is surrounded with a coil unit second thermal shield 17a and a coil unit thermal shield 8a. A helium tank 2b where liquid helium is reserved is surrounded with a helium unit second thermal shield 17b and a helium reservoir thermal shield 8b. The coil unit second thermal shield 17a and a coil unit thermal shield 8a are cooled down by a coil unit two-stage Giford-MacMahon cycle refrigerator 50a, and the helium unit second thermal shield 17b and a helium reservoir thermal shield 8b are cooled down by a helium reservoir two-stage Giford-MacMahon refrigerator 50b.

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 a superconducting magnet which can be easily maintained and reduced in size and weight.

[0002]

2. Description of the Related Art FIG. 26 shows, for example, Japanese Unexamined Patent Publication No. 5-136469.
FIG. 2 is a cross-sectional view showing an example of a conventional superconducting magnet described in Japanese Patent Publication No. JP-A No. 2004-242242, in which 1 is a superconducting coil, 2a is a coil portion helium tank as a coil cryogenic refrigerant tank that houses the superconducting coil 1, and 2b is a coil. Helium tank 2a
Helium tanks 2b and 5 as cryogenic refrigerant tanks arranged above the coil are coil portion helium tank 2a and helium tank 2
It is a helium pipe that communicates with b. The coil portion helium tank 2a is filled with liquid helium 3 as a cryogenic refrigerant stored in the helium tank 2b supplied through the helium pipe 5. Therefore, the superconducting coil 1 stored in the coil portion helium tank 2a
Is immersed in the liquid helium 3 and kept at a cryogenic temperature.

Reference numeral 8a denotes a coil portion heat shield arranged so as to surround the coil portion helium tank 2a, and 8b denotes a helium reservoir heat shield arranged so as to surround the helium reservoir tank 2b. The heat shield 8a and the helium reservoir heat shield 8b reduce heat intrusion into the coil portion helium tank 2a and the helium reservoir tank 2b. 6 is a liquid nitrogen container filled with liquid nitrogen 7 as a cryogen, and this liquid nitrogen container 6 is thermally connected to the helium reservoir heat shield 8b. Reference numeral 9 denotes a liquid nitrogen cooling pipe which is wound in thermal contact with the coil heat shield 8a. One end of the liquid nitrogen cooling pipe 9 communicates with the bottom of the liquid nitrogen container 6 and the other end is not shown. Communicates with the gas phase portion 6 a above the liquid nitrogen container 6.

Reference numeral 10 denotes a vacuum tank arranged so as to further surround the coil portion heat shield 8a and helium reservoir portion heat shield 8b arranged so as to surround the coil portion helium tank 2a and helium reservoir tank 2b. It is a plurality of columns that support the coil portion helium tank 2 a adiabatically with respect to the vacuum tank 10.

Reference numeral 12 denotes a Joule-Thomson cycle refrigerator for liquefying the evaporated helium gas in the helium tank 2b,
Reference numeral 13 is a compressor, 14 is a precooler for cooling high-temperature room-temperature high-pressure helium gas with helium gas returned at low temperature and low pressure, and 15 is high-pressure low-temperature helium gas cooled to a predetermined temperature to approximately atmospheric pressure. A Joule-Thomson valve that is isenthalpically expanded to liquefy a part of the expanded gas, 16 is disposed in the gas phase portion above the helium tank 2b, and liquid helium generated by the Joule-Thomson valve 15 evaporates in the helium tank 2b. It is a condenser for condensing and liquefying helium gas.

Next, the operation of the conventional superconducting magnet will be described. The superconducting coil 1 is cooled to an extremely low temperature (for example, 4.2 by liquid helium 3 in the helium tank 2a of the coil portion).
It is cooled to K) and has zero electric resistance, so-called superconducting state. Therefore, an exciting current is supplied to the superconducting coil 1 from an external power source (not shown) for the superconducting magnet via a current lead (not shown) to generate a required magnetic field. Then, the helium reservoir heat shield 8b is cooled to about 80K by heat conduction from the liquid nitrogen container 6 filled with the liquid nitrogen 7. Further, this liquid nitrogen 7 is a liquid nitrogen cooling pipe 9
Is circulated to cool the coil heat shield 8a.
Therefore, the helium tank 2b and the coil portion helium tank 2
The heat entering the heat a is vacuum-insulated by the vacuum chamber 10, and the radiant heat is blocked by the helium reservoir heat shield 8b and the coil heat shield 8a, so that the heat entering is reduced. Further, in order to support the magnetic field generated by the superconducting coil 1 and the weight of the superconducting coil 1, a column 11 is arranged between the superconducting coil 1 and the vacuum container 10.
Further, in order to reduce heat invasion, the column 11 has a thermal anchor in the middle coil heat shield 8a. However, the heat intrusion cannot be completely prevented, and the liquid helium 3 always continues to evaporate. Therefore, the above-mentioned Joule-Thomson refrigerator 12 is driven and the liquid helium generated by the Joule-Thomson valve 15 is condensed into the condenser 16
The helium gas thus evaporated is condensed and liquefied. Thereby, the evaporation of the liquid helium 3 in the helium reservoir 2b can be reduced or the evaporation amount can be made zero.

As another conventional example, the following superconducting magnet has been proposed. FIG. 27 shows, for example, JP-A-2
FIG. 6 is a cross-sectional view showing another example of the conventional superconducting magnet described in Japanese Patent Publication No. 298765. In this conventional superconducting magnet, a second heat shield 17 is arranged so as to surround the helium tank 2 that houses the superconducting magnet 1 so as to be immersed in the stored liquid helium 3, and the second heat shield 17 A heat shield 8 is arranged so as to surround the vacuum chamber 10 and further surrounds the heat shield 8.
Is provided. And Gifford McMahon Cycle Refrigerator 1 which is one of the cold storage refrigerators that are resistant to impurities
8 is used, the heat shield 8 is cooled by the first heat stage 19 of the Gifford-McMahon cycle refrigerator 18, and the second heat shield 1 is cooled by the second heat stage 20.
7 is cooled, and further, the helium tank 2 is cooled by the third heat stage 21.

The structure of the Gifford-McMahon cycle refrigerator 18 will be described with reference to FIG. Reference numeral 31 is a cylinder formed by coaxially connecting and integrating pipes whose diameters are successively reduced. Reference numeral 32 is a first stage displacer slidably arranged in the first stage of the cylinder 31.
Reference numeral 3 denotes a second-stage displacer, which is slidably disposed in the second-stage of the cylinder 31, like the first-stage displacer 32.
Is a third-stage displacer slidably arranged in the third stage of the cylinder 31. No)) is connected and integrated. 35, 3
Reference numerals 6 and 37 are provided to prevent helium gas from leaking between the first, second and third stage displacers 32, 33 and 34 and the respective stages of the cylinder 31.
Stage seal, 2nd stage seal and 3rd stage seal, 19,
Reference numerals 20 and 21 respectively denote a first-stage heat stage, a second-stage heat stage and a third-stage heat stage, 44, 45 and 46, which are arranged on the outer peripheral surface of each low-temperature end of the cylinder 31.
Is a space formed between the end surface of each stage of the cylinder 31 and the first-stage, second-stage and third-stage displacers 32, 33 and 34, respectively, the first-stage expansion space, the second-stage expansion space and the third stage. The first-stage expansion space, 38 is the first-stage regenerator using copper wire mesh as the regenerator material in the first-stage displacer 32, and 39 is 2
A lead ball was used as a regenerator material in the stage displacer 33. 2
The third-stage regenerator 40 is a third-stage regenerator using Ho-Er-Ru as a regenerator material in the third-stage displacer 34.

Reference numeral 13 is a compressor for compressing helium gas, 41 is an intake valve as a valve mechanism for controlling the timing of supplying high-pressure gas from the compressor 13 to the Gifford-McMahon cycle refrigerator 18, and 42 is a Gifford-McMahon cycle refrigerator 18. An exhaust valve as a valve mechanism that controls the timing of discharging low-pressure gas from the compressor 13 to the compressor 13, and 43 is a first, second, and third stage displacer 3 in the cylinder 31.
It is a drive motor that reciprocates 2, 33, 34 and opens and closes the intake valve 41 and the exhaust valve 42 in conjunction with this reciprocating motion.

The Gifford-McMahon cycle refrigerator 18 configured as described above operates as follows. First,
First stage, second stage and third stage displacer 32, 33,
34 is at the lowermost end, the intake valve 41 is open, and the exhaust valve 42 is closed.
The high-pressure helium gas compressed in 3 is supplied. As a result, the first, second and third expansion spaces 44, 4
5, 46 are in a high pressure state.

Next, the first-stage, second-stage and third-stage displacers 32, 33, 34 move upward, and accordingly, high-pressure helium gas is expanded into the first-stage, second-stage and third-stage expansion spaces 44, It is supplied to 45 and 46 one after another. During this time,
The intake and exhaust valves 41, 42 do not move. Therefore,
When the high-pressure helium gas passes through the first-stage, second-stage, and third-stage regenerators 38, 39, 40, it is cooled to a predetermined temperature by each regenerator material. Then, when the first, second and third stage displacers 32, 33, 34 are at the uppermost ends, the intake valve 41 is closed and the exhaust valve 42 is opened after a short delay. At this time, the high-pressure helium gas expands adiabatically to generate freezing. Therefore, the helium gas existing in the expansion spaces 44, 45, 46 of the first, second and third stages becomes low temperature and low pressure at each temperature level.

Then, by moving the first, second and third displacers 32, 33, 34 downward, low temperature and low pressure helium gas is stored in the third, second and first stages of cold storage. After passing through the containers 40, 39 and 38, the gas is exhausted from the exhaust valve 42. At this time, the low-temperature and low-pressure helium gas is stored in the third, second, and first-stage regenerators 40, 3
After cooling the cold storage materials 9 and 38, they are returned to the compressor 13. Then, the first-stage, second-stage and third-stage displacers 32, 33, 34 are moved to the lowermost ends, and the volumes of the first-stage, second-stage and third-stage expansion spaces 44, 45, 46 are minimized. Closed, the exhaust valve 42 is closed and the intake valve 4
1 is opened, and high-pressure helium gas compressed by the compressor 13 is supplied, and the pressure in the expansion spaces 44, 45, 46 of the first, second and third stages changes from low pressure to high pressure. The above process is performed as one cycle. In this way, by repeating the above operation, the temperatures of the first, second and third heat stages 19, 20, 21 are cooled to 70K, 20K, 4.2K, respectively. here,
The three-stage Gifford-McMahon cycle refrigerator 18 has been explained, but the number of cylinders, displacers, regenerators, seals, and expansion spaces of the two-stage Gifford-McMahon cycle refrigerator is reduced from three to two. The other operations are similar to those of the three-stage Gifford McMahon cycle refrigerator 18. At this time, if the above-mentioned operation is repeated in the two-stage Gifford-McMahon cycle refrigerator, the first-stage and the second-stage heat stages are respectively 50
K and 4.2K.

[0013]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the superconducting magnet as described in Japanese Patent No. 6469, the coil heat shield 8a and the helium reservoir heat shield 8b are cooled by the liquid nitrogen 7 as described above, so that the liquid nitrogen 7 can be replenished at appropriate intervals. Since it is necessary and the liquid nitrogen container 6 must be provided,
There has been a problem that the superconducting magnet becomes large in size and accordingly the weight becomes large. Further, since the coil heat shield 8a and the helium reservoir heat shield 8b cooled by the liquid nitrogen 7 cannot be kept at the liquid nitrogen temperature or lower,
The heat invasion to the coil portion helium tank 2a and the helium reservoir tank 2b due to conduction or radiation depends on the boiling point temperature (77K) of the liquid nitrogen 7. As a result, there is also a problem that there is a limit in reducing the evaporation amount of the liquid helium 3 in the coil helium tank 2a and the helium reservoir tank 2b.

Further, the container for storing the liquid helium 3 is
Since the coil portion helium tank 2a and the helium reservoir tank 2b are divided into two places, the heat shield is the coil portion heat shield 8
a and a helium reservoir heat shield 8b. When both are thermally integrated via a heat transfer member, the thermal resistance of the connection becomes a problem. Therefore, if a conventional regenerator is installed at the coil heat shield 8a, the helium reservoir heat shield 8b is not sufficiently cooled and the temperature rises, so that heat intrusion into the helium reservoir tank 2a increases. Further, if the conventional regenerator type refrigerator is installed in the helium reservoir heat shield 8b, the coil heat shield 8a is not sufficiently cooled and the temperature becomes high, so that heat intrusion into the coil helium tank 2a becomes large. In either case, there was a problem that the evaporation of liquid helium 3 was large.

Further, in order to reduce the evaporation amount of the liquid helium 3, a Joule-Thomson cycle refrigerator 12 is provided. The Joule-Thomson cycle refrigerator 12 has helium as a working gas in the pores of the Joule-Thomson valve 15. There is a problem that not only the clogging due to slight impurities in the gas is likely to occur and handling is difficult, but also the cost is high because the Joule-Thomson cycle refrigerator 12 itself has a complicated structure.

On the other hand, in the conventional superconducting magnet described in JP-A-2-298765, liquid helium 3 is used.
Since the Gifford-McMahon cycle refrigerator 18 that is resistant to impurities is used to reduce the evaporation amount of helium gas, clogging due to slight impurities of helium gas is caused as compared with the conventional superconducting magnet using the Joule-Thomson cycle refrigerator 12. It is less likely to occur, easy to handle, simple in structure, and low in cost. However, the refrigerating capacity of the Gifford McMahon cycle refrigerator 18 depends on the temperature at which helium gas is liquefied (4K
Table) and temperature when cooling the heat shield (10K or more)
In, the optimum cycle frequency (cycle number per unit time) is different. Therefore, if the cycle frequency suitable for cooling the heat shield is deteriorated, the ability to liquefy the helium gas deteriorates. Conversely, if the cycle frequency suitable for liquefying the helium gas is deteriorated, the cooling capacity of the heat shield deteriorates
There is a problem that heat invasion into the helium tank 2 is increased and the evaporation amount of the liquid helium 3 is increased. Therefore, the liquefaction capacity of the helium gas in the Gifford-McMahon cycle refrigerator 18 was not sufficient, and it was necessary to improve the liquefaction capacity.

The present invention has been made to solve the above problems, and an object thereof is to obtain a superconducting magnet which can be downsized and which can reduce the evaporation amount of liquid helium.

[0018]

In a superconducting magnet according to the present invention, a superconducting coil, a coil cryogenic refrigerant tank for accommodating the superconducting coil and storing a cryogenic refrigerant, and a cryogenic temperature for the coil are provided. A cryogenic refrigerant reservoir provided in communication with the cryogenic tank and supplying the cryogenic refrigerant to the coil cryogenic refrigerant tank, a refrigerant reservoir heat shield surrounding the cryogenic refrigerant reservoir, and a coil electrode A coil heat shield provided to surround the low-temperature refrigerant tank and having a thermal resistance between the low temperature refrigerant heat shield and a refrigerant reservoir heat shield, and a vacuum tank provided to surround the refrigerant reservoir heat shield and the coil heat shield. Which is a superconducting magnet, wherein the regenerator for cooling the refrigerant reservoir heat shield for cooling the refrigerant reservoir heat shield, and the regenerator for cooling the coil heat shield for cooling the coil heat shield, Equipped with It is intended.

Further, in the superconducting magnet according to the present invention, the beam chamber, the pair of superconducting coils provided above and below the beam chamber so as to be thermally separated from each other, the superconducting coil being housed, and the cryogenic refrigerant. A cryogenic refrigerant tank for storing a coil portion, a cryogenic refrigerant reservoir tank that is provided in communication with the coil cryogenic refrigerant tank and supplies cryogenic refrigerant to the coil cryogenic refrigerant tank, and the cryogenic refrigerant tank And a coil portion heat shield having a thermal resistance between the refrigerant reservoir heat shield, which is provided to surround the coil reservoir cryoshield, and the refrigerant reservoir heat shield. A superconducting magnet having a heat shield and a vacuum chamber surrounding the heat shield, the cool storage refrigerating machine for cooling the heat sink of the refrigerant reservoir for cooling the heat shield of the refrigerant reservoir, and the coil portion. heat Those having a coil portion thermal shield cooling for regenerative refrigerator for cooling the Rudo.

Further, the refrigerant reservoir heat shield and the coil heat shield are each constituted of double heat shields, and the regenerator for cooling the refrigerant reservoir heat shield and the coil heat shield is a two-stage refrigerator. This is a Gifford McMahon cycle refrigerator.

Further, the refrigerant reservoir heat shield and the coil heat shield are each constituted by a single heat shield, and the regenerator for cooling the refrigerant reservoir heat shield and the coil heat shield is a single stage type. It is a Gifford McMahon cycle refrigerator.

Further, in the superconducting magnet according to the present invention, the superconducting coil, the cryogenic refrigerant tank for accommodating the superconducting coil and storing the cryogenic refrigerant, and the cryogenic refrigerant tank are provided so as to surround the cryogenic refrigerant tank. A superconducting magnet comprising a heat shield and a vacuum chamber provided so as to surround the heat shield, wherein a regenerator for cooling the heat shield cools the heat shield, and at least a part of the heat stage is a pole. A regenerator for cooling a cryogenic refrigerant tank, which is exposed to a gas phase portion of the cryogenic refrigerant tank and liquefies the vaporized gas of the cryogenic refrigerant, is provided.

Further, the bellows tube is attached so as to be thermally separated from the heat shield so that one end is opened to the atmosphere side and the other end is opened to the gas phase portion of the cryogenic refrigerant tank, and the bellows tube is opened to the atmosphere side. The cold storage refrigerator for cooling the cryogenic refrigerant tank is attached so that the heat stage of the cold storage refrigerant for cooling the cryogenic refrigerant tank faces the cryogenic refrigerant tank from the end.

Further, in the superconducting magnet according to the present invention, the superconducting coil, the cryogenic refrigerant tank for accommodating the superconducting coil and storing the cryogenic refrigerant, and the cryogenic refrigerant tank are provided so as to surround the cryogenic refrigerant tank. A superconducting magnet comprising a heat shield and a vacuum chamber provided so as to surround the heat shield, wherein the heat shield cooling regenerator for cooling the heat shield and at least a part of the heat stage are poles. A cold storage refrigerator for cooling a cryogenic refrigerant tank, which cools the cryogenic refrigerant tank by thermally connecting to a wall surface of the cryogenic refrigerant tank, is provided.

[0025]

According to the present invention, there is provided a cold storage type refrigerator for cooling the refrigerant reservoir heat shield and for cooling the coil heat shield for cooling the refrigerant reservoir heat shield and the coil heat shield, respectively. Therefore, both the coil heat shield and the coolant reservoir heat shield can be cooled without using liquid nitrogen. Then, the temperature reached by the regenerator is extremely lower than the boiling temperature of liquid nitrogen, heat invasion by conduction or radiation to the cryogenic refrigerant tank and coil cryogenic refrigerant tank is reduced, and the cryogenic refrigerant evaporates. The amount can be reduced. Further, it is not necessary to attach a liquid nitrogen container, and the size can be reduced.

Further, the heat entering the beam chamber causes the temperature of the coil heat shield to rise, so that the heat entering the cryogenic refrigerant reservoir and the coil cryogenic refrigerant tank increases, but the refrigerant reservoir heat shield and Since the cold storage refrigerator for cooling the refrigerant reservoir heat shield and the coil heat shield for cooling the coil heat shield are provided, the coil heat shield and the refrigerant reservoir heat shield can be used without using liquid nitrogen. Are both well cooled. Therefore,
The heat penetration into the cryogenic refrigerant reservoir and the coil portion cryogenic refrigerant tank is reduced, and the evaporation amount of the cryogenic refrigerant can be reduced.

In addition, the refrigerant reservoir heat shield and the coil heat shield are composed of double heat shields, and the cold storage type refrigerator for cooling the refrigerant reservoir heat shield and the coil heat shield is a two-stage type. Gifford McMahon cycle refrigerator. Therefore, clogging due to slight impurities in the working gas of the cold storage refrigerator is suppressed, and the refrigerator is easily handled. Further, since the double heat shield is cooled by the two-stage Gifford-McMahon cycle refrigerator, the refrigerant reservoir portion and the coil heat shield configured by the double heat shield are both cooled, and the double heat shield is Since the temperature of the heat shield on the low temperature side of the heat shield is lower than that when there is only one heat shield, heat intrusion into the cryogenic refrigerant reservoir tank and the coil portion cryogenic refrigerant tank is further reduced,
The evaporation amount of the cryogenic refrigerant can be reduced.

In addition, the refrigerant reservoir heat shield and the coil heat shield are constituted by a single heat shield, and the regenerator for cooling the refrigerant reservoir heat shield and the coil heat shield is a single stage type. Gifford McMahon cycle refrigerator. Therefore, it is possible to cool the refrigerant reservoir and the coil heat shield, which are composed of a single heat shield, without taking up space, and reduce the heat intrusion into the cryogenic refrigerant reservoir and the coil cryogenic refrigerant bath. Therefore, the evaporation amount of the cryogenic refrigerant can be reduced.

Generally, the refrigerating capacity of the cold storage type refrigerator depends on the cycle frequency. In the ideal state, the higher the cycle frequency, the higher the refrigerating capacity. However, in reality, as the cycle frequency increases, the processing flow rate per unit time increases, so that the capacity of the compressor becomes insufficient and the heat exchange efficiency of the regenerator decreases. As a result, the refrigeration amount does not increase or even decreases even if the cycle frequency increases. That is, the cycle frequency has an optimum value. Further, the amount of processing per unit time varies depending on the operating temperature of the cold storage refrigerator. Therefore, the optimum value of the cycle frequency depends on the operating temperature. Therefore, when the required operating temperature is different, the refrigerating capacity of the regenerator will be improved if the cycle frequency is made different according to the operating temperature.

According to the present invention, the regenerator for cooling the heat shield for cooling the heat shield and at least a part of the heat stage are exposed in the vapor phase portion of the cryogenic refrigerant tank to liquefy the vaporized gas of the cryogenic refrigerant. Since it is equipped with a cold storage refrigerator for cooling a cryogenic refrigerant tank, a cold storage refrigerator for cooling a heat shield for cooling a heat shield and a cryogenic refrigerant tank for liquefying an evaporated gas of a cryogenic refrigerant are cooled. It is possible to operate both the regenerator type refrigerator and the cold regenerator type refrigerator at the optimum cycle frequency, and to cool the heat shield and liquefy the vaporized gas of the cryogenic refrigerant under the optimum operating conditions. As a result, the temperature of the heat shield can be further lowered, and the evaporation amount of the cryogenic refrigerant can be further reduced.

Further, the bellows tube is attached so as to be thermally separated from the heat shield. Here, the temperature of the heat shield and the temperature of the cylinder of the regenerator for cooling the cryogenic refrigerant tank adjacent to the heat shield are different. Therefore, if the bellows tube and the heat shield are in good thermal contact, the temperature gradient of the bellows tube and the temperature gradient of the cylinder are different. Further, there is a cryogenic refrigerant gas atmosphere between the cylinder and the bellows tube, and if the temperature gradient is different, convection occurs and heat invasion into the cryogenic refrigerant tank increases. However, since the bellows tube is thermally separated from the heat shield, the temperature gradient between the bellows tube and the cylinder becomes the same, and heat loss due to convection in the bellows tube can be reduced. As a result, heat penetration into the cryogenic refrigerant tank is reduced, and the evaporation amount of the cryogenic refrigerant can be reduced.

Further, a regenerator for cooling the heat shield for cooling the heat shield, and a cryogenic refrigerant tank for cooling the cryogenic refrigerant tank by thermally connecting at least a part of the heat stage to the wall surface of the cryogenic refrigerant tank. Since it is provided with a regenerator for cooling, a regenerator type refrigerator for cooling the heat shield for cooling the heat shield and a regenerator type refrigerator for cooling the cryogenic refrigerant tank for cooling the cryogenic refrigerant tank Can be operated at the optimum cycle frequency, cooling of the heat shield and cooling of the cryogenic refrigerant tank can both be performed under optimum operating conditions, and the evaporation amount of the cryogenic refrigerant can be reduced.

[0033]

Embodiments of the present invention will be described below with reference to the drawings. Example 1. The first embodiment is an application of the present invention to a superconducting magnet for a synchrotron radiation device. 1 is a sectional view showing a superconducting magnet according to a first embodiment of the present invention. In the figure, the same or corresponding parts as those of the conventional superconducting magnet shown in FIGS. Is omitted.

In the figure, 17a is a second heat shield for the coil portion arranged inside the coil heat shield 8a so as to surround the coil helium bath 2a, and 17b is inside the helium reservoir heat shield 8b for the helium storage tank. Helium reservoir second heat shield arranged so as to surround 2b, 50
Reference numeral a is a two-stage coil unit Gifford-McMahon cycle refrigerator as a regenerator for cooling the heat shield of the coil unit. This two-stage coil unit Gifford-McMahon cycle refrigerator 50a has its first stage heat stage 51a.
The coil heat shield 8a to the second stage heat stage 5
The coil portion second heat shield 17a is cooled by 2a. Reference numeral 13a is a compressor that circulates a helium gas, which is a working gas, at a predetermined pressure in the two-stage coil unit Gifford-McMahon cycle refrigerator 50a. 50b
Is a helium reservoir two-stage Gifford-McMahon cycle refrigerator as a regenerator for cooling the refrigerant reservoir heat shield. The helium reservoir two-stage Gifford-McMahon cycle refrigerator 50b is the first stage heat. The stage 51b cools the helium reservoir heat shield 8b, and the second stage heat stage 52b cools the helium reservoir second heat shield 17b. Reference numeral 13b is a compressor for circulating the helium gas, which is a working gas, in the helium reservoir two-stage Gifford-McMahon cycle refrigerator 50b in the same manner as the compressor 13a.

Reference numerals 60a and 60b respectively denote a detachable current lead movable portion and a detachable current lead fixed portion for supplying a current to the superconducting coil 1, and 101 is immersed in the liquid helium 3 in the helium reservoir 2b and accommodated therein. 1
A permanent current switch consisting of a superconducting wire that operates in the mode of a persistent current flowing through the beam chamber, 61 a beam chamber, 62 a beam chamber heat shield arranged so as to surround the beam chamber 61, 63 a beam chamber heat shield 62
Is a beam portion second heat shield arranged so as to surround the. Although not shown, the beam chamber heat shield 62 is thermally connected to the coil heat shield 8a, and the beam second heat shield 63 is thermally connected to the coil second heat shield 17a. Reference numeral 25 denotes a magnetic shield provided on the outer periphery of the vacuum chamber 10. The magnetic shield 25 prevents the magnetic field generated by the superconducting coil 1 from leaking to the outside.

In the superconducting magnet according to the first embodiment constructed as described above, the superconducting coil 1 is cooled to a cryogenic temperature (for example, 4.2K) by the liquid helium 3 in the helium tank 2a of the coil portion, and becomes the superconducting state. In this state, the detachable current lead movable portion 60a is lowered to electrically contact the detachable current lead fixing portion 60b, and an exciting current is supplied from an external superconducting magnet power source (not shown) to a predetermined value. Generate a magnetic field. Then, when in a steady state, the superconducting coil 1 is passed through the permanent current switch 101.
To allow current to flow through the removable current lead movable part 60.
a is raised to break the electrical contact with the detachable current lead fixing portion 60b. Therefore, the superconducting coil 1 is in the permanent current mode, and a predetermined magnetic field can be generated in a state where the external superconducting magnet power supply is disconnected. On the other hand, the inside of the beam chamber 61 is evacuated to a high vacuum, and the electrons accelerated to a high energy are guided in this. The trajectory of the movement of the electrons is regulated by the magnetic field generated by the pair of superconducting coils 1 arranged so as to sandwich the bee chamber 61.

Here, the superconducting coil 1 is immersed in the liquid helium 3 filled in the helium bath 2a of the coil portion and kept at a cryogenic temperature. Then, the liquid helium 3 is supplied from the helium reservoir tank 2b provided above the coil portion helium tank 2a through the helium pipe 5. Further, the vacuum tank 10 is evacuated between the helium tank 2b and the coil portion helium tank 2a.
From the helium tank 2b and the coil portion helium tank 2a due to convection. Furthermore, heat intrusion exists in the form of radiation and conduction. Therefore, in order to reduce heat invasion to the coil portion helium tank 2a and the helium reservoir tank 2b due to radiation and conduction, the coil portion helium tank 2
The coil portion second heat shield 17a is arranged so as to surround a, and the coil portion heat shield 8a is arranged so as to surround the coil portion second heat shield 17a. Also,
The helium reservoir second heat shield 17b is arranged so as to surround the helium reservoir tank 2b, and the helium reservoir heat shield 8b is arranged so as to surround the helium reservoir second heat shield 17b. That is, the coil heat shield and the refrigerant reservoir heat shield are configured by double heat shields.

A column 11 is provided between the coil portion helium tank 2a and the helium reservoir tank 2b so as to fix their positions. Then, the heat invasion due to conduction mainly occurs through the pillar 11. In particular, the coil portion helium tank 2a has the superconducting coil 1 present therein.
It is necessary to have a pillar 11 that can withstand the weight of 1 and the electromagnetic force generated by the superconducting coil 1. Therefore, the pillar 11 must be thick and strong. For this reason, heat penetration due to conduction from the column 11 increases.

In order to reduce the heat penetration, a two-stage coil unit Gifford-McMahon cycle refrigerator 50a is provided. The coil unit two-stage Gifford-McMahon cycle refrigerator 50a is supplied with high-pressure helium gas from the compressor 13a and operates by discharging low-pressure helium gas to the compressor 13a. Coil heat shield 8a
Is the first stage heat stage 51a of the coil section two-stage Gifford-McMahon cycle refrigerator 50a, and the coil section second heat shield 17a is the second stage heat stage 5 of the coil section two-stage Gifford-McMahon cycle refrigerator 50a.
Cool with 2a. As a result, the coil heat shield 8
a is about 80K, and the coil portion second heat shield 17a is 2
Can be cooled to about 0K. And since the coil part 2nd heat shield 17a can be cooled to about 20K, the heat invasion to the coil part helium tank 2a will be the heat intrusion from 20K,
Heat penetration can be reduced as compared with cooling with liquid nitrogen. Further, since the two-stage coil unit Gifford-McMahon cycle refrigerator 50a is disposed in the vicinity of the column 11, heat can be efficiently introduced from the column 11.

On the other hand, the helium storage tank 2b also receives heat from a column (not shown), though not so much as the coil portion helium tank 2a. Further, the coil portion helium tank 2a and the helium reservoir tank 2b are connected by a helium pipe 5, but in this portion, a heat shield is arranged so as to cover the vicinity of the helium pipe 5 in order to save space. Therefore, the coil portion heat shield 8a and the coil portion second heat shield 17 are provided.
The heat transfer area between a and the helium reservoir heat shield 8b and the helium reservoir second heat shield 17b is small, and the heat conduction is poor. Further, the coil portion heat shield 8a and the coil portion second
The heat shield 17a, the helium reservoir heat shield 8b, and the helium reservoir second heat shield 17b do not use a material having a high thermal conductivity in order to prevent an eddy current. From the above, even if the refrigerating capacity of the coil section two-stage Gifford-McMahon cycle refrigerator 50a is sufficient, even the helium reservoir part heat shield 8b and the helium reservoir part second heat shield 17b can be obtained. It cannot be cooled sufficiently. Therefore, apart from the coil section two-stage Gifford-McMahon cycle refrigerator 50a, a helium reservoir two-stage Gifford-McMahon cycle refrigerator 50b as a regenerator for cooling the heat shield of the refrigerant reservoir is provided near the helium tank 2b. It is installed in. This two-stage helium reservoir Gifford-McMahon cycle refrigerator 50b is supplied with high-pressure helium gas from the compressor 13b and is operated by exhausting low-pressure helium gas to the compressor 13b to operate the helium reservoir heat shield 8b. In the first stage heat stage 51b of the two-stage Gifford McMahon cycle refrigerator 50b, the helium reservoir second heat shield 17b in the second stage heat stage 52b of the helium reservoir two-stage Gifford McMahon cycle refrigerator 50b,
Cool to 80K and 20K respectively. Therefore,
The heat penetration into the helium reservoir 2b is from 20K, and the heat penetration can be reduced as compared with cooling with liquid nitrogen.

On the contrary, the helium reservoir two-stage Gifford-McMahon cycle refrigerator 50b alone has the coil portion heat shield 8a and the coil portion second heat shield 17a for the reason described above even if the refrigerating capacity is sufficient. It is not possible to sufficiently cool even. Therefore, by using both the coil section two-stage Gifford-McMahon cycle refrigerator 50a and the helium reservoir two-stage Gifford-McMahon cycle refrigerator 50b, heat intrusion into the coil section helium tank 2a and helium reservoir tank 2b is reduced. Therefore, the evaporation amount of liquid helium 3 can be reduced.

As described above, according to the first embodiment, the coil section two-stage Gifford-McMahon cycle refrigerator 50 is used.
a and the helium reservoir two-stage Gifford-McMahon cycle refrigerator 50b cools the coil heat shield and the refrigerant reservoir heat shield, respectively, so that the cooling performance can be improved and the evaporation amount of the liquid helium 3 can be increased. A small and lightweight superconducting magnet for a synchrotron, which can be reduced in size, has a longer supply interval of liquid helium, and can be simplified in maintenance, can be obtained.

The coil heat shield is composed of the coil heat shield 8a and the coil second heat shield 17a, and the refrigerant reservoir heat shield is composed of the helium reservoir heat shield 8b and the helium reservoir heat shield 17b. The two-stage coil unit Gifford-McMahon cycle refrigerator 50a and the helium reservoir two-stage Gifford-McMahon cycle refrigerator 50b cool the coil unit heat shield and the refrigerant reservoir heat shield, respectively. Therefore, the cooling performance can be further improved, and the evaporation amount of the liquid helium 3 can be further reduced.

Example 2. The second embodiment is an application of the present invention to a superconducting magnet for a synchrotron radiation device. In the second embodiment, as shown in FIG.
In the superconducting magnet according to the first embodiment, a coil unit single-stage Gifford-McMahon cycle refrigerator 50c is newly provided as a regenerator for cooling the heat shield of the coil unit. This single-stage coil unit Gifford-McMahon cycle refrigerator 50c is connected to a compressor 13c that supplies helium gas, which is a working gas, at a high pressure, and further, the first stage heat stage 51c of the coil unit heat shield in the vicinity of the column 11. It is arranged so as to cool 8a.

As described above, according to the second embodiment, in the superconducting magnet according to the first embodiment, since the coil unit single-stage Gifford-McMahon refrigerator 50c is newly arranged, the coil unit of the column 11 is provided. The cooling temperature of the portion connected through the heat shield 8a can be lowered, and the weight of the superconducting coil 1 housed in the helium bath 2a of the coil portion and the conduction from the column 11 supporting the electromagnetic force generated by the superconducting coil 1 can be reduced. It is possible to further suppress the amount of vaporization of the liquid helium 3 in the coil helium tank 2a by suppressing the invasion heat.

Example 3. In this third embodiment, the present invention is applied to a superconducting magnet for a levitation railway.
3 is a sectional view showing a superconducting magnet according to Embodiment 3 of the present invention, and FIG. 4 is a sectional view taken along the line IV-IV of FIG. 3, in which 70a is a helium reservoir heat shield 8b.
Helium reservoir single-stage Gifford-McMahon cycle refrigerator as a cold storage refrigerator for cooling the refrigerant reservoir heat shield, 70b and 70c respectively for cooling the coil heat shield 8a for cooling the coil heat shield 8a. A first single-stage Gifford-McMahon cycle refrigerator for the coil section and a second single-stage Gifford-McMahon cycle refrigerator for the coil section as a cold storage refrigerator. These helium reservoir single-stage Gifford-McMahon cycle refrigerators 70a, coil part first single-stage type and coil part second single-stage type Gifford-McMahon cycle refrigerator 70b, 70
One compressor 13a for supplying helium gas as a working gas is connected to c. 130 is a pillar 1
A member having a high thermal conductivity such as aluminum or copper between the intermediate part of 1 and the first heat stages 71b and 71c of the coil part first and coil part second single-stage Gifford-McMahon cycle refrigerators 70b and 70c. , 110 is a current lead for supplying an exciting current to the superconducting coil 1, 81 is a thermal anchor provided in the middle portion of the current lead 110 in thermal contact with the coil heat shield 8a, and 82 is In order to recover the vaporized gas of the liquid helium 3 in the coil portion helium tank 2a, a recovery pipe is provided so as to open to the gas phase part in the upper part of the helium reservoir tank 2b, and 84 is a current lead cooling pipe.

As described above, according to the third embodiment, the heat shield is cooled by a plurality of refrigerators, that is, the helium reservoir heat shield 8b is the helium reservoir single-stage Gifford-McMahon cycle refrigerator 70a, and the coil portion. Heat shield 8a
Is cooled by the coil unit first single-stage Gifford-McMahon cycle refrigerator 70b and the coil unit second single-stage Gifford-McMahon cycle refrigerator 70c, so that the heat load of each heat shield unit is frozen. Machine 7
0a, 70b, 70c can share the heat shield evenly, and can evenly cool the heat shield, reduce heat invasion to the helium tank 2b and the coil portion helium tank 2a by radiation, and reduce the evaporation amount of the liquid helium 3. can do.
Also, a plurality of columns 11 that directly connect the room temperature part and the helium tank.
Thermal anchor 81 of the middle part of the
Can be reliably cooled via the heat transfer member 130, the helium reservoir heat shield 8b, and the coil heat shield 8a so as to directly connect the above-mentioned refrigerators 70a, 70b, 70c to the first-stage heat stages 71a, 71b, 71c. Therefore, the helium tank 2b for heat conduction and the helium tank 2 for the coil portion
It is also possible to reduce the heat penetration into a.

Example 4. FIG. 5 is a sectional view showing a two-stage type Gifford-McMahon cycle refrigerator according to the fourth embodiment of the present invention. In the figure, the same or corresponding parts as those of the conventional Gifford-McMahon cycle refrigerator shown in FIG. The same reference numerals are given and the description thereof is omitted.

In the figure, reference numeral 38 is a first-stage regenerator, and the first-stage regenerator 38 is constructed, for example, by filling a high temperature side with copper mesh and a low temperature side with lead balls. 39 is a second stage regenerator, and this second stage regenerator 39 is, for example, Ho-Er-Ru, Er-N
It is filled with regenerator materials with compositions such as i, GdRh, Er-Ni-Co, and Ey-Yb-Ni.

A two-stage Gifford having the above structure
The McMahon refrigerator operates as follows. First, the first and second stage displacers 32 and 33 are at the bottom end,
With the intake valve 41 opened and the exhaust valve 42 closed, the high-pressure helium gas compressed by the compressor 13 is introduced into the first-stage and second-stage expansion spaces 44, 45 to be in a high-pressure state. There is. Next, the first-stage and second-stage displacers 32, 33 move upward, and along with this, high-pressure helium gas is expanded in the first-stage and second-stage expansion spaces 4
4,45. During this time, the intake and exhaust valves 41, 42 do not move. The high-pressure helium gas is cooled to a predetermined temperature by each regenerator material when passing through the first-stage and second-stage regenerators 38, 39. Then, when the first-stage and second-stage displacers 32, 33 are at the uppermost ends, the intake valve 41 is closed and the exhaust valve 42 is opened, and the high-pressure helium gas expands to a low pressure and freezing occurs. At this time, the first-stage and second-stage expansion spaces 44, 45
The helium gas present in is low temperature and low pressure. Then, by moving the first-stage and second-stage displacers 32, 33 downward, low-temperature, low-pressure helium gas passes through the first-stage and second-stage regenerators 38, 39 and is exhausted from the exhaust valve 42. To be done. At this time, the low temperature and low pressure helium gas is stored in the first and second stage regenerators 38, 39.
After cooling the regenerator material, the process returns to the compressor 13. After that, in a state where the volumes of the first-stage and second-stage expansion spaces 44, 45 are minimized, the exhaust valve 42 is closed, the intake valve 41 is opened, and the high-pressure helium gas compressed by the compressor 13 is introduced, 1st and 2nd stage expansion space 4
The pressure of 4, 45 changes from low pressure to high pressure. This two-stage Gifford-McMahon cycle refrigerator operates with the above process as one cycle.

Here, the two-stage Gifford McMahonsa
The refrigeration amount of the icicle refrigerator can be expressed by the following equation. Q₁= ∫_V1P₁dV Q_Two= ∫_V2P_TwodV In addition, Q₁: Freezing amount of the first stage P₁1st stage expansion space pressure V₁: Volume of the first expansion space Q_Two: Second stage frozen amount P_Two: Pressure in the second expansion space V_Two: Volume of the second expansion space Is. Increase refrigeration capacity for liquefying cryogenic refrigerant gas
To increase the refrigerator, that is, V₁, V_TwoTo increase
Just do it. However, V₁And V_TwoFrozen with larger
Because the processing flow rate of the machine increases,
The lesser 13 is required, and the power of the motor 43 is increased.
I have to ask. Therefore, cryogenic refrigerant gas
Even if the ability to liquefy is increased, the efficiency will decrease.
So V₁+ V _TwoConstant, the compressor 13
The motor 43 is a conventional motor, and is a liquid of cryogenic refrigerant gas.
If you try to increase the conversion ability,₁Decrease V
_TwoIt turns out that it is sufficient to increase. And V₁+ V_Two
Is constant, V_TwoAs V increases₁Decreases
It Then, from the above equation, the cooling of the first heat stage 19
Freezing capacity is reduced and the temperature of the first heat stage 19 is high.
Become As a result, heat invasion of the second heat stage 20
Input increases, and as a result, the refrigerating capacity of the second heat stage 20
Decrease, that is, the ability to liquefy cryogenic refrigerant gas also decreases
To do. Therefore, the first stage expansion for the second stage expansion space 45
Volume ratio of space 44 (V₁/ V _Two) Has an optimal range
Will be.

In order to investigate this optimum range, an experiment was conducted using the experimental apparatus shown in FIG. In this experimental apparatus, the cylinder 31 is arranged in a vacuum container 131, the temperature of the first heat stage 19 is measured by a Pt—Co temperature sensor 132, and the temperature of the second heat stage 20 is measured by a Ge temperature sensor 133. The cartridge heater 134 was attached to the second heat stage 20, and the temperature of each stage when the cartridge heater 134 was loaded was measured. The heater load amount at this time corresponds to the freezing amount of the refrigerator. The first heat stage 19 has a radiation shield plate 13 for preventing radiation from room temperature to the second heat stage 20 and improving measurement accuracy.
5 was arranged. Then, the diameter of the first-stage expansion space is made constant with this experimental device and the diameter of the second-stage expansion space is increased.

FIG. 7 shows the measurement results obtained by the above experimental apparatus. In FIG. 7, the horizontal axis represents the volume of the first expansion space / the volume of the second expansion space (V ₁ / V ₂ ), and the vertical axis represents the volume of the second heat stage at the helium gas condensation temperature of 4.2K. The freezing capacity is described. From this experimental result, if the maximum refrigerating capacity is 0.9 W and the volume of the first expansion space / the volume of the second expansion space (V ₁ / V ₂ ) is in the range of 0.45 to 2.8. It can be seen that it has a refrigerating capacity of 0.45 W or more. Also, since the experiment of FIG. 7 uses the same compressor 13 and the same drive motor 43, the required electric input is almost constant. Therefore, the two-stage Gifford
Volume of the first expansion space of the McMahon cycle refrigerator / 2
The volume (V ₁ / V ₂ ) of the stage expansion space is 0.45 to 2.
By setting it in the range of 8, the refrigerating capacity for liquefying the helium gas can be improved, and at the same time, the efficiency can be improved.

Example 5. FIG. 8 is a sectional view showing a two-stage Gifford-McMahon cycle refrigerator according to Embodiment 5 of the present invention. In the fourth embodiment, the first-stage regenerator 38 and the second-stage regenerator 39 are integrated in the first-stage and second-stage displacers 32 and 33, respectively. The regenerator 38 and the second-stage regenerator 39 are separately provided, and the first-stage cylinders 31 and 1
The second stage displacer 32, the second stage cylinder 120 and the second stage displacer 33 are independently provided, and the first stage regenerator 38 and the first stage cylinder 31 are connected to the second stage regenerator 39 and the second stage cylinder, respectively. 120 is connected to each of the communication pipes. In this case, the first-stage regenerator 38 and the second-stage regenerator 39 are in a stationary state, but the operation of the cycle is the same as that of the two-stage type Gifford-McMahon cycle refrigerator of the fourth embodiment, and the same dimension. Under the condition, the refrigerating capacity will be almost the same.

Example 6. The sixth embodiment is an application of the present invention to a superconducting magnet for a synchrotron radiation device. 9 is a sectional view showing a superconducting magnet according to Embodiment 6 of the present invention. In the figure, 80 is a two-stage Gifford-McMahon cycle refrigerator for helium liquefaction as a regenerator for cooling a cryogenic refrigerant tank. This two-stage Gifford-McMahon cycle refrigerator for helium liquefaction 80 is Second heat stage 20
Is exposed to the gas phase part of the helium reservoir 2b. The sixth embodiment has the same configuration as the first embodiment except that a two-stage Gifford-McMahon cycle refrigerator 80 for liquefying helium is provided.

That is, in the sixth embodiment, a cryogenic refrigerant tank is composed of the coil portion helium tank 2a and the helium reservoir tank 2b, and the coil portion heat shield 8a, the coil portion second heat shield 17a, the helium reservoir heat shield 8b and The helium reservoir second heat shield 17b constitutes a heat shield. Then, the coil heat shield 8a is provided by the first and second heat stages 51a and 52a of the coil two-stage Gifford-McMahon cycle refrigerator 50a.
The second heat shield 17a of the coil portion is cooled, and the first and second heat stages 51b and 5b of the Gifford-McMahon cycle refrigerator 50b of the two-stage helium reservoir portion are cooled.
The helium reservoir heat shield 8b and the helium reservoir second heat shield 17b are cooled by 2b. further,
The helium gas evaporated in the helium tank 2b is directly liquefied by the second heat stage 20 of the helium liquefying two-stage Gifford-McMahon cycle refrigerator 80.

Here, in the helium liquefaction two-stage Gifford-McMahon cycle refrigerator 80, the volume ratio of the first-stage expansion space to the second-stage expansion space is 1.4, and the helium condensing temperature (4.2K). Refrigeration capacity is cycle frequency 45
It is 0.8 W at rpm. This refrigerating capacity depends on the cycle frequency. FIG. 10 uses the experimental apparatus shown in FIG. 6 to change the cycle frequency of the drive motor 43,
This figure shows the effect of cycle frequency on refrigeration capacity. From FIG. 10, when the temperature is 4.2 K, the optimum cycle frequency is 45 rpm and the refrigeration amount at that time is 0.8 W.
Is. On the other hand, in the case of 10K, the optimum cycle frequency is 6
It is 0 rpm. If the temperature is 4.2K, 60 rp
When operated at m, the amount of refrigeration is 0.35 W, and only about 40% of the amount of refrigeration at the optimum cycle frequency can be obtained.
That is, the optimum cycle frequency tends to increase as the temperature increases. Therefore, it is understood that it is more efficient to separate the refrigerator for liquefying helium and the refrigerator for cooling the heat shield.

As described above, according to the sixth embodiment, the regenerator for cooling the heat shield and the regenerator for liquefying helium are respectively provided. Therefore, by optimizing the cycle frequency of the Gifford-McMahon cycle refrigerator applied to the portions where the refrigeration generation temperature differs between the heat shield cooling unit and the helium liquefying unit, high efficiency operation is possible, and liquid helium 3 The amount of evaporation is reduced, and in some cases it is not evaporated. As a result, the superconducting magnet for the synchrotron becomes smaller and lighter, the cooling performance is improved, and the evaporation amount of the liquid helium 3 is significantly reduced. Then, the replenishment interval of the liquid helium 3 is greatly extended, and the maintenance can be simplified.

Example 7. Embodiment 7 is an application of the present invention to a superconducting magnet of a synchrotron radiation device. 11 is a sectional view showing a superconducting magnet according to Embodiment 7 of the present invention, and FIG. 12 is a partial sectional view showing a first stage heat stage 19 of a two-stage Gifford McMahon refrigerator 80 for liquefying helium. In the figure, 182
Is a soft metal, and 83 is a first heat stage connection part.
Here, this Example 7 was carried out as described above except that the first heat stage 19 of the two-stage Gifford-McMahon cycle refrigerator 80 for liquefying helium was used for cooling the second heat shield 17b of the helium reservoir. The configuration is the same as in Example 6.

According to the seventh embodiment, the first stage heat stage 19 and the first stage heat stage stage connecting portion 8 are provided.
2 is a two-stage type Gifford-McMahon cycle refrigerator 80 for liquefying helium when it is installed
You can insert it by sliding. Further, since the soft metal 182 such as indium is sandwiched between the first-stage heat stage 19 and the first-stage heat stage connecting portion 83, thermal contact between the two is improved, and
Since the cooling of the helium reservoir second heat shield 17b can be enhanced by the first heat stage 19 via the first heat stage connecting portion 83, heat intrusion into the helium reservoir 2b can be further reduced.

Example 8. The eighth embodiment is an application of the present invention to a superconducting magnet for a synchrotron radiation device. FIG. 13 is a sectional view showing a superconducting magnet according to Embodiment 8 of the present invention, in which 181 is a current lead cooling member. In the eighth embodiment, a current lead cooling member 181 made of, for example, a copper flexible wire is used to intermediate the first heat stage 19 of the two-stage Gifford-McMahon cycle refrigerator 80 for helium liquefaction and the detachable current lead movable part 60a. The configuration is the same as that of the sixth embodiment except that the detachable current lead movable portion 60a can be cooled by thermally connecting it to an appropriate portion of.

The removable current lead movable part 60a is cooled by the evaporated helium gas, but when the evaporation amount of the liquid helium 3 decreases, the amount of cooling of the removable current lead movable part 60a becomes insufficient and the temperature rises. However, heat invasion into the helium tank 2b is increased. According to the eighth embodiment, the detachable current lead movable portion 60a is cooled by the first heat stage 19 of the two-stage Gifford-McMahon cycle refrigerator 80 for helium liquefaction via the current lead cooling member 181 to be detachable. It is possible to reduce heat intrusion into the helium reservoir 2b due to the temperature rise of the current lead movable portion 60a.

Example 9. The ninth embodiment is an application of the present invention to a superconducting magnet for a levitation railway.
14 is a sectional view showing a superconducting magnet according to Embodiment 9 of the present invention. In the ninth embodiment, the coil portion helium tank 2a and the helium reservoir tank 2b constitute a cryogenic refrigerant tank, the coil portion heat shield 8a and the helium reservoir heat shield 8b constitute a heat shield, and the helium reservoir single stage Gifford is provided. The helium reservoir heat shield 8b is cooled by the first stage heat stage 71a of the McMahon cycle refrigerator 70a, and the helium storage tank 2b is cooled by the second stage heat stage 20 of the helium liquefying Gifford McMahon cycle refrigerator 80. It liquefies the evaporated helium gas.

As described above, according to the ninth embodiment, the helium reservoir heat shield 8b is cooled by the helium reservoir single-stage Gifford-McMahon cycle refrigerator 70a,
It is possible to suppress heat from entering the helium tank 2b. The helium gas evaporated in the helium tank 2b and the coil portion helium tank 2a is liquefied by a helium liquefying two-stage Gifford-McMahon cycle refrigerator 80 different from the helium reservoir single-stage Gifford-McMahon cycle refrigerator 70a. As a result, the cycle frequency of each refrigerator can be optimized for high-efficiency operation, cooling performance can be improved, and the evaporation amount of liquid helium 3 can be reduced.
The replenishment interval of the liquid helium 3 is greatly extended, and the maintenance can be simplified.

Example 10. The tenth embodiment is an application of the present invention to a superconducting magnet for a levitation railway. FIG. 15 is a sectional view showing a superconducting magnet according to Embodiment 10 of the present invention. In this tenth embodiment, a helium liquefaction two-stage Gifford-McMahon cycle refrigerator 80 has its second heat stage 20 connected to the helium tank 2.
The structure is the same as that of the above-described third embodiment except that it is exposed to the gas phase portion in b.

According to the tenth embodiment, the helium reservoir single-stage type Gifford-McMahon cycle refrigerator 70a and the coil portions first and second single stages for cooling the helium reservoir heat shield 8b and the coil heat shield 8a, respectively. Type Gifford McMahon cycle refrigerator 70b, 70
In addition to the effect of the third embodiment, the helium gas evaporated in the helium tank 2b and the coil portion helium tank 2a is liquefied by a helium liquefaction two-stage Gifford-McMahon cycle refrigerator 80 different from c. hand,
The cycle frequency of each refrigerator can be optimized for high-efficiency operation, the cooling performance can be improved, the evaporation amount of liquid helium 3 can be reduced, the replenishment interval of liquid helium 3 can be greatly extended, and maintenance can be simplified. be able to.

Example 11. The eleventh embodiment is an application of the present invention to a superconducting magnet for a levitation railway. 16 is a sectional view showing a superconducting magnet according to Embodiment 11 of the present invention. In the eleventh embodiment, the coil unit second single-stage Gifford-McMahon cycle refrigerator 7 is used.
0c is removed, and the first heat stage 7 of the first single-stage coil type Gifford-McMahon cycle refrigerator 70b is removed.
1b by coil heat shield 8a and current lead 110
The structure is the same as that of the above-described tenth embodiment except that and are cooled.

The current lead 110 is the helium tank 2 in the coil section.
The helium gas evaporated in a and the helium tank 2b is cooled by flowing through the current lead cooling pipe 84. However, when the evaporation amount of the liquid helium 3 is reduced, the cooling effect by the current lead cooling pipe 84 is reduced, the temperature of the current lead 110 is increased, and the heat penetration into the coil helium tank 2a is increased. The amount of evaporation does not drop below a certain value. According to the eleventh embodiment, since the current lead 110 is cooled by the first heat stage 71b of the coil unit first single-stage Gifford-McMahon cycle refrigerator 70b, the temperature rise of the current lead 110 is suppressed, It is possible to reduce heat intrusion into the coil helium bath 2a.

Example 12 The twelfth embodiment is an application of the present invention to a superconducting magnet for a levitation railway. 17 is a sectional view showing a superconducting magnet according to Embodiment 12 of the present invention. This Example 12 is a two-stage Gifford McMahon cycle refrigerator 8 for liquefying helium.
The structure is similar to that of the ninth embodiment except that the helium reservoir heat shield 8b is cooled by the first heat stage 19 of 0. According to this twelfth embodiment, a two-stage Gifford-McMahon cycle refrigerator 8 for liquefying helium is provided.
Since the helium reservoir heat shield 8b is cooled by the first heat stage 19 of 0, the helium reservoir heat shield 8b
The cooling capacity of b is improved, and the temperature of the helium reservoir heat shield 8b is lowered. As a result, the heat penetration into the helium reservoir 2b is reduced, and the evaporation amount of the liquid helium 3 is further reduced.

Example 13 The thirteenth embodiment is an application of the present invention to a superconducting magnet for a levitation railway. 18 is a sectional view showing a superconducting magnet according to Embodiment 13 of the present invention. In this Example 13, the low temperature side of the current lead 110 is, for example, Y-Ba-Cu-O, Bi-Sr-Ca-Cu-.
Same as Example 11 except that the high temperature superconducting current lead 110a is made of a high temperature superconductor such as O, Tl-Ba-Ca-Cu-O, La-Ba-Cu-O. Has been done. It is cooled to about 50K by the thermal anchor 81 of the current lead 110, and the high temperature superconducting current lead 110a is placed on the lower temperature side than that, so that it is in the superconducting state. Therefore, the electrical resistance of the high temperature superconducting current lead 110a is zero, and the thermal conductivity is small. When current is flowing through the current lead 110 and the high-temperature superconducting current lead 110a, Joule heat is zero on the temperature lower side than the thermal anchor 81, and heat loss due to heat conduction is small. Therefore,
The heat penetration into the coil helium tank 2a is reduced, and the evaporation amount of the liquid helium 3 is also reduced.

Example 14 The fourteenth embodiment is an application of the present invention to a superconducting magnet for a synchrotron radiation device. FIG. 19 is a sectional view showing a superconducting magnet according to Embodiment 14 of the present invention. This Example 1
4 is the superconducting magnet according to the first embodiment,
A two-stage Gifford-McMahon cycle refrigerator 80 for liquefying helium is arranged in the vacuum of the vacuum tank 10, and the second
The heat stage 20 is brought into contact with the wall surface of the helium reservoir 2b to cool it.

According to the fourteenth embodiment, the helium tank 2b
The evaporated helium gas inside is reliquefied when it touches the wall surface of the helium reservoir 2b. Since the cylinder 31 of the helium liquefaction two-stage Gifford-McMahon cycle refrigerator 80 is arranged in a vacuum, convective heat transfer around the cylinder 31 can be eliminated and heat loss can be reduced. As a result, the evaporation of the liquid helium 3 can be further reduced.

Example 15. The fifteenth embodiment is an application of the present invention to a superconducting magnet for a synchrotron radiation device. 20 is a sectional view showing a superconducting magnet according to Embodiment 15 of the present invention. This Example 1
5 is configured in the same manner as in Example 14 except that the helium reservoir heat shield 17b is cooled by the first heat stage 19 of the helium liquefaction two-stage Gifford-McMahon cycle refrigerator 80. ing. According to this fifteenth embodiment, the first heat stage 1 of the two-stage Gifford-McMahon cycle refrigerator 80 for liquefying helium.
9 and the helium reservoir heat shield 17b are thermally connected to each other, the helium reservoir heat shield 17b is further cooled and the temperature is lowered, heat invasion into the helium reservoir tank 2b can be reduced, and vaporization of the liquid helium 3 is prevented. It can be reduced.

Example 16 The sixteenth embodiment is an application of the present invention to a superconducting magnet for a levitation railway. 21 is a sectional view showing a superconducting magnet according to Embodiment 16 of the present invention. In the sixteenth embodiment, the coil portion helium tank 2a and the helium reservoir tank 2b constitute a cryogenic refrigerant tank, the coil portion heat shield 8a and the helium reservoir heat shield 8b constitute a heat shield, and the helium reservoir single-stage Gifford is provided. The helium reservoir heat shield 8b is cooled by the first stage heat stage 71a of the McMahon cycle refrigerator 70a, and the helium tank 2b is cooled by the second stage heat stage 20 of the helium liquefying Gifford McMahon cycle refrigerator 80. It is designed to cool the wall surface.

As described above, according to the sixteenth embodiment, the helium reservoir heat shield 8b is cooled by the helium reservoir single-stage Gifford-McMahon cycle refrigerator 70a to prevent heat from entering the helium reservoir 2b. In addition, the wall surface of the helium tank 2b is cooled by the helium liquefaction two-stage Gifford-McMahon cycle refrigerator 80, and the helium gas evaporated in the helium tank 2b is liquefied by touching the wall surface of the helium tank 2b. Also,
Helium Reservoir Single-stage Gifford ・ Two-stage Gifford for helium liquefaction different from McMahon cycle refrigerator 70a
Helium tank 2b by McMahon cycle refrigerator 80
Since the wall surface of the refrigerator is cooled, the cycle frequency of each refrigerator can be optimized for high efficiency operation, the cooling performance is improved, the evaporation amount of liquid helium 3 can be reduced, and the replenishment interval of liquid helium 3 can be reduced. It can be greatly extended and the maintenance can be simplified.

Example 17 22 shows a first embodiment of the present invention.
FIG. 7 is a cross-sectional view of essential parts showing a superconducting magnet according to No. 7. In the figure, 90 is a bellows tube configured so that one end is opened to the atmosphere side and the other end is opened to the gas phase part of the helium reservoir 2b, 91 is a radiation shielding plate, and this bellows pipe 90 is a helium reservoir heat The shield 8b and the helium reservoir second heat shield 17b are thermally separated from each other and arranged in a non-contact manner. Then, in the seventeenth embodiment, the two-stage Gifford-McMahon cycle refrigerator 80 for liquefying helium is bellows which is thermally separated from the helium reservoir heat shield 8b and the helium reservoir second heat shield 17b. Tube 90
It is attached so as to face the inside of the helium reservoir 2b from the open end on the atmosphere side.

According to the seventeenth embodiment, the bellows tube 90
And helium reservoir heat shield 8b and helium reservoir second
Since the bellows tube 90 is disposed in non-contact with the heat shield 17b, the temperature distribution of the bellows tube 90 becomes equal to the temperature distribution of the cylinder 31 of the two-stage Gifford-McMahon cycle refrigerator 80 for helium liquefaction, and the bellows tube 90 and the cylinder 31 are separated from each other. There is no natural convection between them. Therefore, there is no increase in heat penetration due to convection in the bellows tube 90. Further, the radiation shield plate 91 is not in contact with the helium reservoir heat shield 8b and the helium reservoir second heat shield 17b, but since the overlapping portion is provided, the radiation from the vacuum chamber 10 enters the helium reservoir 2b. Nothing. As a result, heat penetration does not increase by disposing the two-stage Gifford-McMahon cycle refrigerator 80 for liquefying helium in the superconducting magnet.

Example 18. FIG. 23 is a first embodiment of the present invention.
FIG. 9 is a cross-sectional view of essential parts showing a superconducting magnet according to No. 8, in which 92 is made of, for example, glass epoxy resin, phenol resin, or the like, and the radiation shielding plate 91, the helium reservoir heat shield 8b, and the helium reservoir second heat shield 17b. Is a thermal insulator that is disposed between and and thermally separates the radiation shield plate 91 from the helium reservoir heat shield 8b and the helium reservoir second heat shield 17b. The other structure is similar to that of the seventeenth embodiment. According to the eighteenth embodiment, the bellows tube 90, the helium reservoir heat shield 8b, and the helium reservoir second heat shield 17b are made of the heat insulator 9.
Although they are in contact with each other through 2, the thermal insulator 92 is sandwiched between them, so that they are close to being thermally non-contact, and the same effect as that of the above-mentioned seventeenth embodiment can be obtained.

Example 19 FIG. 24 shows the first embodiment of the present invention.
FIG. 9 is a cross-sectional view of a main part showing a superconducting magnet according to No. 9, in which 93 is, for example, a styrofoam, a multilayer heat insulating material,
Bellows tube 9 made of felt mat, natural rubber, etc.
It is a convection preventive material disposed between 0 and the cylinder 31 of the two-stage Gifford-McMahon cycle refrigerator 80 for liquefying helium. The other structure is similar to that of the seventeenth embodiment. According to the nineteenth embodiment, the bellows tube 90 and the cylinder 3 of the helium liquefying two-stage Gifford-McMahon cycle refrigerator 80 are protected by the convection preventive material 93.
Further, convection with 1 is prevented, and heat intrusion into the helium tank 2b can be further reduced.

Example 20. FIG. 25 shows a second embodiment of the present invention.
2 is a cross-sectional view of a main part of a superconducting magnet according to No. 0, in which 94 is a heat conduction block provided on the wall surface of the helium reservoir 2b, and is a second stage of the helium liquefying two-stage Gifford-McMahon cycle refrigerator 80. The freezing generated in the multi-stage heat stage 20 is conducted to the helium reservoir 2b. In this Example 20, the second heat stage 20 and the heat conduction block 94 were processed into a tapered shape,
The second heat stage 20 is arranged while sliding on the heat conduction block 94. The soft metal 18 is provided between the second heat stage 20 and the heat conduction block 94.
It is sandwiched between 2 and has good thermal contact. Therefore, the refrigeration generated in the second heat stage 20 of the helium liquefaction two-stage Gifford-McMahon cycle refrigerator 80 can be efficiently transferred to the helium reservoir 2b.

In each of the above embodiments, the Gifford-McMahon cycle refrigerator is used as the regenerator, but the Gifford-McMahon cycle refrigerator is a regenerator that operates in the Gifford-McMahon cycle. In addition to the machine, it also includes a cold storage refrigerator that operates in an improved Solvay cycle similar to the Gifford McMahon cycle.

In each of the above embodiments, the Gifford-McMahon cycle refrigerator is used as the regenerator, but the regenerator is not limited to the Gifford-McMahon cycle refrigerator, and is, for example, Stirling. It can also be applied to refrigerators, pulse tube refrigerators, and Burmeyer refrigerators.

[0083]

Since the present invention is constituted as described above, it has the following effects.

The superconducting magnet according to the present invention is provided so as to communicate with a superconducting coil, a coil cryogenic refrigerant tank for accommodating the superconducting coil and storing cryogenic refrigerant, and a coil cryogenic refrigerant tank. , A cryogenic refrigerant reservoir for supplying the cryogenic refrigerant to the coil cryogenic refrigerant tank, a refrigerant reservoir heat shield surrounding the cryogenic refrigerant reservoir, and a coil cryogenic refrigerant tank surrounding the cryogenic refrigerant tank A superconducting magnet comprising a coil heat shield having thermal resistance between the refrigerant reservoir heat shield and a vacuum chamber provided surrounding the refrigerant reservoir heat shield and the coil heat shield, Since the regenerator for cooling the refrigerant reservoir heat shield for cooling the refrigerant reservoir heat shield and the coil regenerator for cooling the coil heat shield for cooling the coil heat shield are provided, liquid nitrogen for Not even, can cool the coil portion thermal shield and coolant reservoir unit heat shield, it is not necessary to provide a liquid nitrogen container, nor should periodically replenished liquid nitrogen. Therefore, the superconducting magnet can be reduced in size and weight. Moreover, the coil heat shield and the refrigerant reservoir heat shield are both cooled, the evaporation amount of the cryogenic refrigerant gas is reduced, the replenishment interval of the cryogenic refrigerant can be extended, and the maintenance can be simplified. .

Further, in the superconducting magnet according to the present invention, the beam chamber, the pair of superconducting coils provided above and below the beam chamber so as to be thermally separated from each other, the superconducting coil are stored, and the cryogenic refrigerant is stored. Coil section cryogenic refrigerant tank to liquefy, provided in communication with the coil section cryogenic refrigerant tank, to supply the cryogenic refrigerant tank to the coil section cryogenic refrigerant tank, and to surround the cryogenic refrigerant tank A refrigerant heat shield and a coil, which are provided so as to surround the provided refrigerant reservoir heat shield and the coil cryogenic refrigerant tank and have thermal resistance between the refrigerant reservoir heat shield and the refrigerant reservoir heat shield. A superconducting magnet including a vacuum chamber provided surrounding a partial heat shield, wherein a cold storage type refrigerator for cooling the refrigerant reservoir heat shield for cooling the refrigerant reservoir heat shield, and a coil heat shield. Since it is equipped with a cold storage refrigerator for cooling the coil heat shield for cooling, it is possible to cool the coil heat shield and the refrigerant reservoir heat shield without using liquid nitrogen, so there is no need to provide a liquid nitrogen container. Also, there is no need to replenish liquid nitrogen regularly. Therefore, the superconducting magnet can be reduced in size and weight. Moreover, the coil heat shield and the refrigerant reservoir heat shield are both cooled, the evaporation amount of the cryogenic refrigerant gas is reduced, the replenishment interval of the cryogenic refrigerant can be extended, and the maintenance can be simplified. .

Further, the refrigerant reservoir heat shield and the coil heat shield are constituted by double heat shields, and the regenerator for cooling the refrigerant reservoir heat shield and the coil heat shield is provided as a two-stage Gifford. Since the McMahon cycle refrigerator is used, the double heat shields of the refrigerant reservoir and the coil heat shield are both cooled, and the heat shield on the low temperature side of the double heat shield is lower than the liquid nitrogen temperature. Since the temperature is lower than that when there is only one heat shield, heat intrusion into the cryogenic refrigerant reservoir tank and the coil portion cryogenic refrigerant tank can be reduced, and evaporation of the cryogenic refrigerant can be further reduced. Therefore, it is possible to further reduce the size and weight of the superconducting magnet, and it is possible to further simplify the maintenance.

Further, the refrigerant reservoir heat shield and the coil heat shield are constituted by a single heat shield, and the regenerator for cooling the refrigerant reservoir heat shield and the coil heat shield is provided as a single-stage Gifford. -Since it is a McMahon cycle refrigerator, it can cool the single refrigerant reservoir and coil heat shield sufficiently without taking up space, and prevents heat from entering the cryogenic refrigerant tank and coil cryogenic refrigerant tank. The amount of evaporation of the cryogenic refrigerant can be reduced. Therefore, the superconducting magnet can be further reduced in size and weight, and the maintenance can be simplified.

Further, in the superconducting magnet according to the present invention, the superconducting coil, the cryogenic refrigerant tank for accommodating the superconducting coil and storing the cryogenic refrigerant, and the heat provided around the cryogenic refrigerant tank are provided. A superconducting magnet comprising a shield and a vacuum chamber provided surrounding the heat shield, wherein a regenerator for cooling the heat shield cools the heat shield, and at least a part of the heat stage is a cryogenic refrigerant. Since it is provided with a regenerator for cooling the cryogenic refrigerant tank that is exposed to the gas phase portion of the tank and liquefies the evaporated gas of the cryogenic refrigerant, a regenerator type refrigerator that cools the heat shield and a cryogenic refrigerant Both the regenerator refrigerator that liquefies the gas can be operated at the optimum cycle frequency, and the cooling performance can be improved. Therefore, the temperature of the heat shield can be lowered and the evaporation of the cryogenic refrigerant can be reduced. Therefore, the replenishment interval of the cryogenic refrigerant can be greatly extended, and the maintenance of the superconducting magnet can be greatly simplified.

Further, the bellows tube is attached so as to be thermally separated from the heat shield so that one end is opened to the atmosphere side and the other end is opened to the vapor phase portion of the cryogenic refrigerant tank, and the atmosphere side opening end of the bellows tube is attached. Since the heat stage of the regenerator for cooling the cryogenic refrigerant tank is installed so that the heat stage of the regenerator for cooling the cryogenic refrigerant tank faces the cryogenic refrigerant tank, heat loss due to convection in the bellows pipe is reduced. can do. For this reason, heat intrusion into the cryogenic refrigerant tank is reduced, and the evaporation amount of the cryogenic refrigerant can be reduced. Therefore, the maintenance of the superconducting magnet can be simplified.

Further, in the superconducting magnet according to the present invention, the superconducting coil, the cryogenic refrigerant tank for accommodating the superconducting coil and storing the cryogenic refrigerant, and the heat provided around the cryogenic refrigerant tank are provided. A superconducting magnet comprising a shield and a vacuum chamber provided surrounding the heat shield, wherein a regenerator for cooling the heat shield cools the heat shield, and at least a part of the heat stage is a cryogenic refrigerant. It has a regenerator for cooling the cryogenic refrigerant tank that cools the cryogenic refrigerant tank by thermally connecting it to the wall surface of the tank, so it cools the regenerator type refrigerator that cools the heat shield and the cryogenic refrigerant tank. It is possible to operate both the regenerator type refrigerator and the regenerator type refrigerator that operate at the optimum cycle frequency and improve the cooling performance. Therefore, the temperature of the heat shield can be lowered, and the evaporation of the cryogenic refrigerant in the cryogenic refrigerant tank can be reduced. Therefore, the periodic replenishment interval of the cryogenic refrigerant can be greatly extended, and the maintenance of the superconducting magnet can be greatly simplified.

[Brief description of drawings]

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

FIG. 2 is a sectional view showing a superconducting magnet according to Embodiment 2 of the present invention.

FIG. 3 is a sectional view showing a superconducting magnet according to a third embodiment of the present invention.

4 is a cross-sectional view taken along the line IV-IV of FIG.

FIG. 5 is a schematic cross-sectional view showing a cold storage refrigerator according to Embodiment 4 of the present invention.

FIG. 6 is a cross-sectional view showing an experimental device for a cold storage type refrigerator according to a fourth embodiment of the present invention.

FIG. 7 is a graph showing the relationship between the volume ratio of the first-stage expansion space and the second-stage expansion space and the amount of refrigeration in the cold storage refrigerator according to Embodiment 4 of the present invention.

FIG. 8 is a schematic sectional view showing a cold storage refrigerator according to Embodiment 5 of the present invention.

FIG. 9 is a sectional view showing a superconducting magnet according to Embodiment 6 of the present invention.

FIG. 10 is a graph showing the relationship between the cycle frequency and the amount of refrigeration of the regenerative refrigerator in the superconducting magnet according to Embodiment 6 of the present invention.

FIG. 11 is a sectional view showing a superconducting magnet according to Embodiment 7 of the present invention.

FIG. 12 is a partial cross-sectional view around a first heat stage of a cold storage refrigerator in a superconducting magnet according to Embodiment 7 of the present invention.

FIG. 13 is a sectional view showing a superconducting magnet according to Embodiment 8 of the present invention.

FIG. 14 is a sectional view showing a superconducting magnet according to Embodiment 9 of the present invention.

FIG. 15 is a sectional view showing a superconducting magnet according to Embodiment 10 of the present invention.

FIG. 16 is a sectional view showing a superconducting magnet according to Embodiment 11 of the present invention.

FIG. 17 is a sectional view showing a superconducting magnet according to Embodiment 12 of the present invention.

FIG. 18 is a sectional view showing a superconducting magnet according to Embodiment 13 of the present invention.

FIG. 19 is a sectional view showing a superconducting magnet according to Embodiment 14 of the present invention.

FIG. 20 is a sectional view showing a superconducting magnet according to Embodiment 15 of the present invention.

FIG. 21 is a sectional view showing a superconducting magnet according to Embodiment 16 of the present invention.

FIG. 22 is a cross-sectional view of essential parts showing a superconducting magnet according to Embodiment 17 of the present invention.

FIG. 23 is a cross-sectional view of essential parts showing a superconducting magnet according to Embodiment 18 of the present invention.

FIG. 24 is a cross-sectional view of essential parts showing a superconducting magnet according to Embodiment 19 of the present invention.

FIG. 25 is a cross-sectional view of essential parts showing a superconducting magnet according to Embodiment 20 of the present invention.

FIG. 26 is a sectional view showing an example of a conventional superconducting magnet.

FIG. 27 is a sectional view showing another example of a conventional superconducting magnet.

FIG. 28 is a schematic cross-sectional view showing an example of a cold storage refrigerator in a conventional superconducting magnet.

[Explanation of symbols]

1 superconducting coil, 2a coil portion helium tank (coil portion cryogenic refrigerant tank), 2b helium reservoir (cryogenic refrigerant reservoir), 3 liquid helium (cryogenic refrigerant), 8a coil portion heat shield, 8b helium reservoir heat shield ( Refrigerant reservoir heat shield), 13 Compressor, 17a Coil portion second heat shield (coil portion heat shield), 17b Helium reservoir second heat shield (refrigerant reservoir heat shield), 31
Cylinder, 32 1st stage displacer, 33 2nd stage displacer, 38 1st stage regenerator, 39 2nd stage regenerator, 41 exhaust valve (valve mechanism), 42 intake valve (valve mechanism), 43 drive motor, 44 1 Stage 2 expansion space, 45 Stage 2 expansion space, 50a Coil section 2 stage type Gifford McMahon cycle refrigerator (cooling type refrigerator for coil heat shield cooling), 50b Helium reservoir 2 stage Gifford McMahon cycle refrigerator Machine (cooling type refrigerator for cooling the heat shield of the refrigerant reservoir), 50c coil single-stage Gifford-McMahon cycle refrigerator (cooling type refrigerator for cooling the heat shield of the refrigerant reservoir), 61 beam chamber, 70a helium reservoir Part Single-stage Gifford
McMahon Cycle Refrigerator (Regenerative Refrigerator for Cooling Heat Shield of Refrigerant Reservoir), 70b Coil Part 1st Stage Gifford McMahon Cycle Refrigerator (Regenerative Refrigerator for Cooling Heat Shield of Coil), 70c Coil Part 2nd single-stage Gifford-McMahon cycle refrigerator (cold storage refrigerator for cooling the heat shield of coil part), 80-helium liquefaction 2-stage Gifford McMahon refrigerator (cooling refrigerator for cooling cryogenic refrigerant tank), 90 bellows tube.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akinori Ohara             8-1-1 Tsukaguchihonmachi, Amagasaki-shi Mitsubishi Electric             Central Research Institute Co., Ltd. (72) Inventor Toshiyuki Amano             8-1-1 Tsukaguchihonmachi, Amagasaki-shi Mitsubishi Electric             Itami Manufacturing Co., Ltd. (72) Inventor Takeo Kawaguchi             1-3 1-2 Wadazaki-cho, Hyogo-ku, Kobe-shi             Ryo Electric Co., Ltd.Kobe Works

Claims (7)

[Claims] 1. A superconducting coil, a coil cryogenic refrigerant tank for accommodating the superconducting coil and storing cryogenic refrigerant, and a coil cryogenic refrigerant tank provided in communication with each other.
A cryogenic refrigerant reservoir for supplying the cryogenic refrigerant to the coil cryogenic refrigerant tank, a refrigerant reservoir heat shield provided surrounding the cryogenic refrigerant reservoir, and surrounding the coil cryogenic refrigerant tank And a coil chamber heat shield having thermal resistance between the coolant reservoir heat shield and the refrigerant reservoir heat shield, and a vacuum chamber surrounding the coolant reservoir heat shield and the coil heat shield. A superconducting magnet, a regenerator for cooling the refrigerant reservoir heat shield for cooling the refrigerant reservoir heat shield, and a regenerator for cooling the coil heat shield for cooling the coil heat shield. A superconducting magnet characterized by being equipped. 2. A beam chamber, a pair of superconducting coils provided above and below the beam chamber so as to be thermally separated from each other, and a coil portion cryogenic temperature for accommodating the superconducting coil and storing a cryogenic refrigerant. A refrigerant tank and a cryogenic refrigerant tank provided in communication with the coil portion cryogenic refrigerant tank, the cryogenic refrigerant reservoir tank for supplying the cryogenic refrigerant to the coil portion cryogenic refrigerant tank, and provided to surround the cryogenic refrigerant reservoir tank , A refrigerant reservoir heat shield having a thermal resistance between the refrigerant reservoir heat shield,
A superconducting magnet comprising: a coil heat shield provided to surround the coil cryogenic refrigerant tank; and a vacuum tank provided to surround the refrigerant reservoir heat shield and the coil heat shield. , A cold storage refrigerator for cooling the refrigerant reservoir heat shield for cooling the refrigerant reservoir heat shield, and a cold storage refrigerator for cooling the coil heat shield for cooling the coil heat shield And a superconducting magnet. 3. The refrigerant reservoir heat shield and the coil heat shield are each configured by a double heat shield, and the regenerator for cooling the refrigerant reservoir heat shield and the coil heat shield is a two-stage refrigerator. The superconducting magnet according to claim 1, wherein the superconducting magnet is a Gifford-McMahon cycle refrigerator. 4. The refrigerant reservoir heat shield and the coil heat shield are each constituted by a single heat shield, and the cold storage refrigerator for cooling the refrigerant reservoir heat shield and the coil heat shield is a single stage type. The superconducting magnet according to claim 1, wherein the superconducting magnet is a Gifford-McMahon cycle refrigerator. 5. A superconducting coil, a cryogenic refrigerant tank for accommodating the superconducting coil and storing a cryogenic refrigerant, a heat shield surrounding the cryogenic refrigerant tank, and the heat shield. A superconducting magnet having a vacuum tank provided to surround the cold storage refrigerating machine for cooling the heat shield for cooling the heat shield, and at least a part of a heat stage for the cryogenic refrigerant tank. A superconducting magnet, comprising: a regenerator for cooling a cryogenic refrigerant tank, which is exposed to a phase portion and liquefies the vaporized gas of the cryogenic refrigerant. 6. A bellows tube is attached so as to be thermally separated from a heat shield so that one end is opened to the atmosphere side and the other end is opened to a gas phase part of a cryogenic refrigerant tank, and the bellows tube is opened to the atmosphere side. 6. The cold storage refrigerator for cooling the cryogenic refrigerant tank is attached so that the heat stage of the cold storage refrigerant for cooling the cryogenic refrigerant tank faces the cryogenic refrigerant tank from the end. Superconducting magnet. 7. A superconducting coil, a cryogenic refrigerant tank for accommodating the superconducting coil and storing a cryogenic refrigerant, a heat shield surrounding the cryogenic refrigerant tank, and the heat shield. A superconducting magnet having a vacuum tank provided surrounding the cold storage refrigerating machine for cooling a heat shield for cooling the heat shield, and at least a part of a heat stage on a wall surface of the cryogenic refrigerant tank. And a regenerator for cooling a cryogenic refrigerant tank, which is thermally connected to the cryogenic refrigerant tank to cool the cryogenic refrigerant tank.