JPH07307214A - Superconducting magnet system - Google Patents

Abstract

PURPOSE:To provide a small superconducting magnet system with a large and uniform magnetic spatial field. CONSTITUTION:In a cryostat unit, a space between an outer wall 1a and a heat radiation shield 14 is cooled at a temperature of about 80K by a refrigerator put at an upper part of a lid 2, while a space between the heat radiation shield 14 and a heat radiation shield 13 at a temperature of about 20K. A spherical superconducting coil 9 and a reserve tank 10 are put inside the heat radiation shield 13. A space with atmospheric pressure based on a room temperature and spherical core-shaped heat radiation shields 14a and 13a are included in the spherical superconducting coil 9. The radiation shields 14a and 13a are connected to the heat radiation shields 14 and 13 at the side walls and the cryostat unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a superconducting magnet device which is a strong magnetic field generator used in the fields of physicochemical experiments, substance analysis, medical treatment and the like.

[0002]

2. Description of the Related Art A superconducting magnet device capable of easily obtaining a strong magnetic field plays an important role in various fields such as a manufacturing process for manufacturing various industrial products, a physical chemistry experiment, a substance analysis, and medical treatment. Plays. However, in recent years, high magnetic field homogeneity and widening of the effective magnetic field homogenization region have been simultaneously demanded from the versatility of the purpose. To meet such demands, conventionally, a Helmholtz coil in which a pair of superconducting air-core coils are arranged at appropriate intervals has been used. But,
The magnetic field uniform area of the Helmholtz coil is relatively small with respect to the size of the coil, and if it deviates from the magnetic field uniform area, the magnetic field homogeneity rapidly deteriorates. As a countermeasure, there is a method of combining a double Helmholtz coil and an auxiliary coil, but it has not been sufficient.

This problem is solved by a spherical coil in which the diameter of the coil is continuously changed and the inner and outer surfaces of the coil are wound into a spherical shape. This spherical coil
Compared with the size of the coil, there is an advantage that a wide magnetic field uniform region can be obtained inside the coil. However, the size of the sample that can be inserted is limited because the opening for inserting the sample into the coil of the spherical coil is provided as small as possible so as not to impair the homogeneity of the magnetic field at the intersection of the coil axis and the coil spherical surface. However, there is a problem that the magnetic field uniform region in the spherical coil cannot be fully utilized.

There is also a method in which a spherical superconducting coil is formed using a superconducting wire and the coil is directly stored in a cryostat by an immersion cooling method to form a superconducting magnet device. It was not manufactured because it was virtually impossible to utilize the effective magnetic field uniform region in the spherical coil other than inserting the sample therein.

[0005]

SUMMARY OF THE INVENTION The present invention is to provide a superconducting magnet device using a spherical air-core coil capable of utilizing a wide magnetic field uniform region and capable of inserting and removing a sample.

[0006]

The present invention provides a superconducting magnet device comprising a magnetic field generating superconducting coil, a refrigerant for cooling the superconducting coil, and a cryostat for keeping the superconducting coil at a low temperature. A superconducting magnet device, characterized in that a plurality of superconducting air-core coils are combined and arranged so that the inner and outer surfaces form a sphere, and in the superconducting magnet device of the item, the material of the reel of the spherical superconducting air-core coil is aluminum or aluminum. A superconducting magnet device characterized by using at least one kind of material selected from alloys, copper, and copper alloys, wherein in the superconducting magnet device, a hollow portion is provided in a winding frame of the spherical superconducting air-core coil, A superconducting magnet device, characterized in that a refrigerant is passed through the hollow portion. In the superconducting magnet device, the outer surface of the spherical superconducting air-core coil is covered with at least one member of aluminum, aluminum alloy, copper, and copper alloy. A superconducting magnet device, characterized in that a plurality of heat radiation shield layers are provided inside and outside the superconducting air-core coil,
In the superconducting magnet device according to the item 1, a spherical shell connected to the outside by a worm bore is provided inside the spherical superconducting air-core coil, and a spherical room-temperature room-temperature atmospheric pressure space is provided inside the superconducting magnet device. In the superconducting magnet device according to the item, the winding frame of the spherical superconducting air-core coil, the spherical shell-shaped heat radiation shield layer inside the spherical superconducting air-core coil, and the spherical shell that forms a room temperature and atmospheric pressure space are divided into two. , Assemble a flange on the butt,
A superconducting magnet device characterized by having a structure capable of disassembling, wherein in the superconducting magnet device according to the paragraph, a preliminary tank for a refrigerant is provided in a heat radiation shield layer in a cryostat, and the reel of the spherical superconducting air-core coil is provided. The superconducting magnet device is characterized in that it is connected to the hollow portion of the above and the refrigerant is circulated.

[0007]

With the use of the spherical superconducting coil, the magnetic field generator is compact and can generate a strong magnetic field with a wide magnetic field uniform region.

Since aluminum alloy and copper alloy are used for the winding frame of the superconducting coil and the cover outside the coil, these alloys have a similar coefficient of thermal expansion to that of the superconducting wire, so that they are not deformed or cracked due to temperature changes. It is stable without generation, has high thermal conductivity, and consumes little refrigerant. It is non-magnetic, has mechanical strength, and has good workability.

The cooling efficiency is improved by circulating the cooling medium in the hollow portion of the winding frame for cooling.

By providing a plurality of heat radiation shield layers, the penetration of radiant heat is reduced, the consumption of refrigerant is reduced, and the cryostat can be miniaturized.

By making the region of high magnetic field homogeneity in the spherical coil at room temperature and atmospheric pressure, it becomes easy to attach a sample to which a magnetic field is applied.

By dividing the spherical coil, the heat radiation shield, and the cryostat in the spherical coil into two hemispheres, it is possible to insert a sample or experimental equipment into the cryostat without disassembling the entire cryostat. Becomes

By adopting the indirect cooling method utilizing the thermosiphon effect, the superconducting magnet can be separated from the liquid helium tank, and the superconducting magnet can be easily divided.

[0014]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an external perspective view of a superconducting magnet device using the horizontal type spherical coil of the present invention. Figure 2
It is the perspective view which abbreviate | omitted the service port on the outer surface of the cryostat, and showed the structure inside the cryostat. FIG. 3 is a sectional view showing a detailed configuration of the superconducting magnet device of the present invention.

As shown in FIG. 1, in this embodiment, a spherical coil 9 is arranged near the bottom of a cylindrical cryostat 1 having a bottom, and a refrigerant (liquid helium) 1 is arranged on the top thereof.
There are 5 spare tanks 10. At the upper end of the cryostat 1, there is a flange 2a, and it is in close contact with the flange 2a,
When the cryostat 1 is evacuated, there is a disk-shaped lid 2 that holds the interior vacuum. Flange 2a and lid 2
There are a plurality of holes 7 penetrating therethrough, which are fastened and fixed by bolts and nuts (not shown in the drawing). A refrigerator 6 is provided above the lid 2 to cool the inside of the cryostat to a low temperature. On the outer side surface of the cryostat 1, there is a service port 3 and a disc-shaped lid 4
By removing, the heat radiation shield (not shown) and the spherical coil 9 inside the cryostat 1 can be disassembled and assembled. The flange 4a of the service port 3 and the outer periphery of the lid 4 have a plurality of holes 8 penetrating therethrough, which are tightened by bolts and nuts (not shown in the drawing) to maintain a vacuum. Further, in the center of the lid 4 of the service port 3, there is a hole 5 connected to a warm bore 16 which communicates with the room temperature and atmospheric pressure space inside the spherical coil 9.

As shown in FIG. 2, the cryostat according to the present invention has a total of three layers, that is, an outer wall 1a for holding the interior of the cryostat 1 in a vacuum and two layers of heat radiation shields 13 and 14 for preventing radiant heat from entering the interior. It has a wall structure. The spare tank 10 for the refrigerant 15 and the spherical coil 9 are installed in the innermost wall.

Further details of the structure will be described with reference to FIG.
The inside of the cryostat 1 held in vacuum is about 80K between the outer wall 1a and the heat radiation shield 14 and about between the heat radiation shield 14 and the heat radiation shield 13 due to the refrigerator 6 installed on the lid 2. Each is cooled to a temperature of 20K. The spherical coil 9 and the reserve tank 10 for the refrigerant 15 are installed inside the heat radiation shield 13 of about 20K. Further, spherical shell-shaped heat radiation shields 14a and 13a are also provided inside the spherical coil 9, and are connected to the heat radiation shields 14 and 13 on the side walls.

The refrigerant 15 in the spare tank 10 falls by gravity and passes through a pipe 17 connecting the spare tank 10 of the refrigerant 15 and the spherical coil 9 to a flange from a lower portion of a flange 19 of a winding frame 18 of the spherical coil 9. Hollow part 20 in 19
The ball-shaped coil 9 is indirectly cooled. The cooling medium 15 that has cooled the winding frame 18 of the spherical coil 9 passes through the pipe 17 a from the upper portion of the flange 19 of the winding frame 18 and returns to the cooling medium 15 again.
It circulates in the spare tank 10 of.

The aluminum alloy winding frame 18 of the spherical coil 9 is a spherical shell having an inner diameter of 350 mm, and two hemispherical shells are formed by abutting and connecting the respective flanges 19 to each other. A groove for a coil is provided on the outer surface of the bobbin 18, and a niobium titanium superconducting ultrafine multifilamentary wire is closely wound in the groove so that a magnetic field of 3 Tesla is generated at the center of the coil.
A set of pancake type coils 21 is wound. As a measure against the electromagnetic stress that tends to spread in the radial direction when a large current flows through the circular coil, the pancake type coil 21 is covered with a hemispherical housing 22 made of an aluminum alloy. The coil 21 is adhesively fixed to the winding frame 18 with an epoxy resin. In addition, the room temperature and atmospheric pressure space 23
The spherical shell 23a forming the is a spherical shell having an inner diameter of 210 mm,
A worm bore 16 having an inner diameter of 24 mm is connected to the coil center axis.

Next, a procedure for incorporating a sample or experimental equipment in the room temperature and atmospheric pressure space 23 will be described. First, the flange 16a that hermetically seals the worm bore 16 and the lid 4 of the service port 3 to vacuum is removed. Next, the lid 4 of the service port 3 is removed. Further, the disk-shaped 80K heat radiation shield (copper plate) 14b and the 20K heat radiation shield 13b curved in an arc shape are removed by removing screws (not shown in the drawing) on the outer circumference. Then, the bolt of the flange 19 (not shown in the drawing) is removed, and the hemispherical portion of the spherical coil 9 is removed. Also, hemispherical shell-shaped 80K heat radiation shields 14a and 2
The screws (not shown in the drawing) of the flanges 14c and 13c of the 0K heat radiation shield 13a are removed and removed. Finally, the bolt (not shown in the drawing) of the flange 23b of the spherical shell 23a forming the room temperature and atmospheric pressure space 23 to which the worm bore 16 is connected is removed to form the room temperature and atmospheric pressure space 23. Remove half of the. After this, the sample and the experimental equipment can be installed in the room temperature and atmospheric pressure space 23. The assembly may be performed in the reverse order of the above.

[0021]

As described above, the superconducting magnet device using the spherical coil according to the present invention can obtain a small and wide uniform magnetic field space region, and according to the purpose of work, Since the spherical coil can be easily disassembled, assembled, and maintained, efficient work can be performed.

[Brief description of drawings]

FIG. 1 is an external perspective view of a horizontal superconducting magnet device using a spherical coil of the present invention.

FIG. 2 is a perspective view showing the internal structure of the superconducting magnet device of FIG. 1 with a part of the cryostat omitted.

FIG. 3 is a sectional view of a horizontal superconducting magnet device of the present invention.

[Explanation of symbols]

1 Cryostat 1a (Cryostat) Outer Wall 2 (Cryostat) Lid 2a (Cryostat) Flange 3 Service Port 4 (Service Port) Lid 4a (Service Port) Flange 5 (Open to Warm Bore of Service Port) 6 Refrigeration Machine 7 Hole (on lid of cryostat) Hole 8 (on lid of service port) 9 Spherical coil (whole) 10 Spare tank (for refrigerant) 13, 13a, 13b (20K) Heat radiation shield 14, 14a, 14b ( 80K heat radiation shield 13c (20K spherical heat radiation shield) flange 14c (80K spherical heat radiation shield) flange 15 refrigerant (liquid helium) 16 warm bore 16a (worm bore) flange 17,17a pipe 18 reel 19 (of reel) Flange 20 hollow portion 21 (superconducting) coil 22 housing 23 cold atmospheric space portion 23a spherical shell 23b (the spherical shell) flanges

Claims (8)

[Claims] 1. A superconducting magnet device comprising: a magnetic field generating superconducting coil; a coolant for cooling the superconducting coil; and a cryostat for keeping the superconducting coil at a low temperature, wherein the superconducting coil is a combination of a plurality of circular superconducting air-core coils. A superconducting magnet device characterized in that the outer surfaces are arranged so as to form a sphere. 2. The superconducting magnet device according to claim 1, wherein the material of the winding frame of the spherical superconducting air-core coil is at least one of aluminum, aluminum alloy, copper and copper alloy.
A superconducting magnet device characterized by using more than one kind of material. 3. The superconducting magnet device according to claim 1, wherein a hollow portion is provided in a winding frame of the spherical superconducting air-core coil, and a refrigerant is passed through the hollow portion. 4. The superconducting magnet device according to claim 1, wherein the outer surface of the spherical superconducting air-core coil is covered with at least one member of aluminum, aluminum alloy, copper and copper alloy. . 5. The superconducting magnet device according to claim 1, wherein a plurality of heat radiation shield layers are provided inside and outside the spherical superconducting air-core coil. 6. The superconducting magnet device according to claim 1, wherein a spherical shell connected to the outside by a worm bore is provided inside the spherical superconducting air-core coil, and a spherical space at room temperature and atmospheric pressure is provided inside. Is a superconducting magnet device. 7. The superconducting magnet device according to claim 1, wherein a winding frame of the spherical superconducting air-core coil, and a spherical shell-shaped heat radiation shield layer inside the spherical superconducting air-core coil,
A superconducting magnet device characterized in that a spherical shell that creates a space at normal temperature and atmospheric pressure is divided into two parts, and a flange is provided at the abutting part so that the structure can be assembled and disassembled. 8. The superconducting magnet device according to claim 1, wherein a preliminary tank for the refrigerant is provided in the heat radiation shield layer in the cryostat, and the tank is connected to the hollow portion of the winding frame of the spherical superconducting air-core coil to circulate the refrigerant. A superconducting magnet device characterized by being made.