JPH07162191A - Superconducting magnetic shield structure - Google Patents

Abstract

(57) [Abstract] [Purpose] To simplify the structures of the superconducting shield and the cryostat, obtain a large-scale magnetic shield structure at low cost, and obtain a floor structure with high rigidity. A main cryostat 12 having an opening 13a at one end and vertically arranged with the opening 13a facing downward.
And a tubular structure 13 composed of an outer superconducting shield 11 made of a superconducting material arranged in the main cryostat 12, a sub-cryostat 20 arranged in an opening 13a of the cylindrical structure 13, and a sub-cryostat. The cryostat 20 is provided with a floor superconducting shield 21 made of a superconducting material, and a plurality of superconducting coupled cylindrical openings 21a formed in the floor superconducting shield 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting magnetic shield structure for creating a magnetic shield space in the fields of biomagnetic field measurement, minute magnetic field measurement such as precision physical measurement, and EB exposure of semiconductor manufacturing equipment.

[0002]

2. Description of the Related Art A magnetic shield structure utilizing a superconductor is a magnetic shield structure utilizing the Meissner effect in which magnetic field lines cannot enter the inside of the superconductor. Is to magnetically shield the internal space of the superconducting shield. For example, as shown in FIG. 9, the structure is such that the opening 1a of the superconducting shield 1 made of a tubular structure is oriented horizontally and the inside and outside of the superconducting shield 1 are covered with a cryostat (cooling structure) 2. In such a horizontal type tubular structure, in the case where a person can put inside it or construct a floor on which articles such as materials and devices can be stably placed, the magnetic shield performance is ensured and the superconducting shield 1 The floor structure must be such that no load is applied to the floor.

FIG. 10 shows an example of a conventional floor structure. FIG. 10A is a sectional view and FIG. 10B is a view seen from the direction B in FIG. In the floor structure 4, the floor member 4a is inserted from the opening 1a so that the load does not act on the superconducting shield 1.
The floor member 4a is supported by the external support member 4b.

FIG. 11 shows another example of a conventional floor structure,
FIG. 1A is a sectional view, and FIG. 1B is a perspective view of a main part. A plurality of supporting members 4c are provided on the floor member 4a, while a cylindrical opening 5 is formed on the lower side of the superconducting shield 1 so that
The support member 4c of a penetrates the cylindrical opening 5. In this case, if the length L is sufficiently large with respect to the opening diameter D of the tubular opening 5, it is possible to prevent the magnetic flux from entering from the tubular opening 5.

[0005]

However, in the above-mentioned conventional method, since it is a horizontal type tubular structure, as shown in FIG. 9, ribs 3 are provided to prevent deformation of the cryostat 2 due to its own weight. Therefore, there is a problem that it is necessary to increase rigidity. Further, in the case of the floor structure method shown in FIG. 10, there is a problem that it is difficult to form a rigid floor structure because the floor member 4a is cantilevered, and in the case of FIG. Although it is possible to have a rigid floor structure, the structure of the superconducting shield 1 is complicated, and the cryostat 2 shown in FIG. 9 must have a structure for supporting the load of the superconducting shield 1. There is a problem that the manufacturing cost increases.

In order to solve this problem, the present inventor has
An improvement proposal is made in Japanese Patent Application No. 5-206366. This will be described with reference to FIG. 7. The superconducting shield 1
1 and a cryostat 12 that covers the inner and outer surfaces thereof
The cylindrical structure 13 is formed by and the cylindrical structure 13 is arranged vertically with the opening 13a of the cylindrical structure 13 facing downward, and the cylindrical structure 13 is made of a non-magnetic material. The floor member 15 is provided, and the opening 13 of the tubular structure 13 is provided.
a is a plurality of ring-shaped tubular members 1 made of a high magnetic permeability material.
6a to 16d are arranged in multiple layers. According to this structure, it is not necessary for the cryostat 12 to support the superconducting shield body 11, and the floor member 15 is directly supported on the base plate 14 via the support member 15a, whereby the floor member 15 and the superconducting shield body 11 are supported. Further, the structure of the cryostat 12 can be simplified and the floor structure having high rigidity can be obtained.

By the way, in FIG. 7, in consideration of magnetically shielding the opening 13a of the tubular structure 13 by the superconducting shield 11 in order to improve the magnetic shield performance, the structure shown in FIG. Become. That is, the superconducting shield 11 includes the protruding cylinder 1 surrounding the support member 15a.
1a is formed, and the cryostat 12 has a projection cylinder 11
It is necessary to form a protruding cylinder 12a that surrounds a and a through hole 12b that penetrates the support member 15a. However, integrally forming the projection cylinders 11a and 12a and the through hole 12b in the superconducting shield 11 and the cryostat 12 has a problem that the structure becomes complicated and the manufacturing cost increases.

The present invention solves the above problems and simplifies the structures of the superconducting shield and the cryostat, enables the production of a large-scale magnetic shield structure at low cost, and obtains a highly rigid floor structure. An object of the present invention is to provide a superconducting magnetic shield structure that can be used.

[0009]

In order to achieve the above object, the superconducting magnetic shield structure of the present invention has an opening 13a at one end and is vertically arranged with the opening 13a being the lower side. A cylindrical structure 13 composed of a main cryostat 12 and an outer superconducting shield 11 made of a superconducting material arranged in the main cryostat 12, and an opening 13 a of the cylindrical structure 13. Sub-cryostat 20, a floor superconducting shield 21 made of a superconducting material disposed in the sub-cryostat 20, and a plurality of superconducting cylindrical openings 21a formed in the floor superconducting shield 21. And is provided.

A magnetic shield member 22 made of a high magnetic permeability material may be provided between the main cryostat 12 and the sub-cryostat 20, or may be provided inside the tubular structure 13. Through hole 20 formed in the sub-cryostat 20 and through which a supporting member 15a of the floor member 15 is penetrated
a may be provided. Here, the numbers added to the above configuration are for comparison with the drawings in order to facilitate understanding of the present invention, and the configuration of the present invention is not limited thereby.

[0011]

In the present invention, for example, as shown in FIG.
Since the superconducting magnetic shield structure is placed vertically and the superconducting shields 11 and 21 and the cryostats 12 and 20 are divided into two for the wall and the floor, the structures of the superconducting shield and the cryostat are simplified. .

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an embodiment of the superconducting magnetic shield structure of the present invention. FIG. 1 (A) is a longitudinal sectional view, and FIG. 1 (B) is taken along line BB in FIG. 1 (A). 2 is a perspective view of the sub-cryostat as viewed in the direction of the arrow.

In FIG. 1, an inner surface and an outer surface of a cylindrical outer superconducting shield 11 made of a superconducting material are covered with a main cryostat 12 and are sealed at intervals to form a cylindrical structure 13. The cylindrical structure 13 is arranged on the base 14 with the opening 13a facing downward so that the entire cylindrical structure 13 is placed vertically. As the superconducting material, a well-known material that becomes a superconductor at an extremely low temperature, for example, an oxide superconductor is used. A floor member 15 made of a non-magnetic material is provided in the cylindrical structure 13 and is supported at a predetermined height by a support member 15a.

An opening 13b is provided on the side surface of the cylindrical structure 13, and passes through the opening 13b and onto the floor member 15,
People, articles (materials, devices, etc.) enter and leave. Opening 13
A magnetic shield door (not shown) is installed in b.

An auxiliary cryostat 20 is arranged below the floor member 15. As shown in FIG. 2, a through hole 20a is formed in the sub-cryostat 20, and the support member 15 of the floor member 15 is provided in the through hole 20a.
a is penetrated. In the sub-cryostat 20, a plurality of cylindrical openings 21a are formed in a lattice shape, and a floor superconducting shield 21 is superconductingly coupled by a superconducting material. The lattice-shaped opening of the floor superconducting shield 21 is designed to have a length L that is sufficiently long with respect to its diameter D.

Further, in the opening 13a of the tubular structure 13, between the main cryostat 12 and the sub-cryostat 20, the magnetic shielding member 2 made of a high magnetic permeability material is provided.
2 is provided to prevent the magnetic flux from entering between the main cryostat 12 and the sub-cryostat 20.

FIG. 3 is a plan view showing another embodiment of the floor superconducting shield of the present invention. In this embodiment, the floor superconducting shield has a plurality of cylindrical openings 21a.
Are formed in a honeycomb shape and are superconductingly coupled by a superconducting material. Also in this case, the honeycomb-shaped opening is designed to have a length L sufficiently longer than the diameter D thereof.

FIG. 4 is a schematic sectional view showing various modifications of the magnetic shield member 22 according to the present invention.

FIG. 5 shows a modification of the tubular structure according to the present invention. A cylinder 23 is provided above the wall shield body 11 and the main cryostat 12, and an opening 13 similar to that shown in FIG.
b is formed to secure a length L that is sufficiently long with respect to the opening diameter D.

Next, the function and effect of the present invention having the above structure will be described. As shown in Fig. 6, 1
When combining cylinders with open ends, the height of the superconductor on the side wall of both the inner and outer cylinders becomes high, the cryostat becomes large and the cost becomes high, and the height direction is increased due to lifting. A high space is required, but in the present invention, the superconducting shields 11 and 21 and the cryostats 12 and 20 are divided into two for outside and for the floor, and the superconducting shield and the cryostat constituting the lower part are formed. Due to the compact shape, a large magnetic shield structure can be manufactured at low cost without requiring a very high lifting space.

Further, since the superconducting magnetic shield structure is placed vertically and the superconducting shields 11 and 21 and the cryostats 12 and 20 are divided into two for outside and for the floor, the superconducting shield and the cryostat are separated. The structure is simplified, and it is possible to manufacture superconducting magnetic shield structures by manufacturing in the factory and combining them on site without manufacturing on site, thus reducing manufacturing cost, ensuring quality, shortening construction period, maintenance. Can be facilitated. Further, since the cylindrical structure 13 is placed vertically, its own weight is supported by the end portion on the side of the opening 13a, and the structure of the main cryostat 12 does not need to have a higher rigidity than that of the horizontal placement type. Since the main cryostat 12 does not need to support the superconducting shield 11, the structure is simplified and the manufacturing cost can be reduced. Further, by placing the cylindrical structure 13 vertically, the floor member 15 does not penetrate the wall shield body 11 and the main cryostat 12, and the floor member 15 is directly placed on the substrate 14 via the support member 15a. Since it is supported, the structures of the floor member 15, the superconducting shields 11, 21 and the cryostats 12, 20 can be simplified, and the floor structure with high rigidity can be obtained.

In this case, in order to enhance the magnetic shield performance, the height of the floor member 15 is increased, and as a result, the tubular structure 1
Although the height of 3 is also required to be high, the floor superconducting shield body 21 made of a superconducting material and the magnetic shielding member 22 made of a high magnetic permeability material disposed in the opening 13a prevent magnetic flux from entering from below the floor, It is possible to reduce the height of the structure 13 and thus reduce the manufacturing cost. Further, the floor superconducting shield 21 can be arranged in a self-supporting state.

[0023]

As is clear from the above description, according to the present invention, the structures of the superconducting shield and the cryostat can be simplified, a large magnetic shield structure can be manufactured at low cost, and a floor structure having high rigidity can be obtained. Can be obtained.

[Brief description of drawings]

1 shows an embodiment of a superconducting magnetic shield structure of the present invention, FIG. 1 (A) is a longitudinal sectional view, and FIG. 1 (B) is FIG.
It is sectional drawing seen in the arrow direction along the BB line of (A).

FIG. 2 is a perspective view of the sub-cryostat of FIG.

FIG. 3 is a plan view showing another embodiment of the floor superconducting shield according to the present invention.

FIG. 4 is a schematic cross-sectional view showing various modifications of the magnetic shield member according to the present invention.

FIG. 5 is a cross-sectional view showing a modified example of the tubular structure according to the present invention.

FIG. 6 is a schematic diagram for explaining the effect of the present invention.

FIG. 7 is a cross-sectional view of a superconducting magnetic shield structure for explaining the invention of the prior application.

8A and 8B are views for explaining the problems of the present invention, in which FIG. 8A is a sectional view of a superconducting magnetic shield structure, and FIG.
[Fig. 3] is a partial perspective view of a cryostat.

FIG. 9 is a sectional view showing an example of a conventional superconducting magnetic shield structure.

FIG. 10 shows an example of a conventional floor structure, FIG. 10 (A) is a sectional view, and FIG. 10 (B) is a view seen from the direction B in FIG. 10 (A).

11A and 11B show another example of a conventional floor structure, FIG. 11A is a sectional view, and FIG. 11B is a perspective view of a main part.

[Explanation of symbols]

11 ... Outer superconducting shield, 12 ... Main cryostat, 13 ... Cylindrical structure 13a ... Opening, 15 ... Floor member, 15a ... Supporting member 20 ... Sub-cryostat, 20a ... Through hole, 21 ... Floor superconducting shield 21a ... Cylindrical opening, 22 ... Magnetic shielding member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shinichi Shibuya 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd. (72) Sumio Mukaiyama 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction Within the corporation

Claims (3)

[Claims] 1. A main cryostat having an opening at one end and vertically arranged with the opening facing downward, and an outer superconducting shield made of a superconducting material arranged in the main cryostat. A tubular structure, a sub-cryostat disposed in an opening of the tubular structure, a superconducting shield for a floor made of a superconducting material disposed in the sub-cryostat, and a superconducting shield for the floor. A superconducting magnetic shield structure comprising: a plurality of superconducting coupled cylindrical openings formed in the body. 2. The superconducting magnetic shield structure according to claim 1, wherein a magnetic shielding member made of a high magnetic permeability material is provided between the main cryostat and the sub-cryostat. 3. A floor member made of a non-magnetic material, which is disposed inside the tubular structure, and a through hole formed in the sub-cryostat for penetrating a supporting member of the floor member. The superconducting magnetic shield structure according to claim 1 or 2.