JPH07147496A - Superconductive magnetic shielding structure - Google Patents

Abstract

PURPOSE:To enable a superconductive magnetic shielding structure to shield an object contained in it from the influence of a magnetic field which penetrates through an opening and to be set compact in structure as a whole by a method wherein a superconductive case of circular or square tube is superconductively joined to the opening of the superconductive magnetic shielding structure. CONSTITUTION:A cylindrical magnetic shield structure main body 1 which is provided with closed upper and lower ends and an opening 4 at its side wall and formed of superconductive material board, a cylindrical case 2 whose upper and lower ends are both open is large in the L/D ratio (L: length, D: diameter) and formed of superconductive material board, and the cylindrical case 2 is superconductively joined to the cylindrical magnetic shield structure main body 1 in one piece with superconductive paste by inserting the one end of the case 2 into the opening 4 of the main body 1. By this setup, a superconductive magnetic shield structure wherein the structure main body l and the case 2 communicate with each other can be obtained. Thus, an external magnetic line of force is indirectly weakened, and an external magnetic field can be prevented from penetrating into a shield structure main body through an opening.

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 making a relatively large 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. It is about things.

[0002]

2. Description of the Related Art A magnetic shield structure using a superconductor is a magnetic shield structure utilizing the Meissner effect that magnetic lines of force cannot enter the inside of the superconductor. For example, a tubular structure is made of a material having the Meissner effect. Then, it is cooled to a temperature below the critical temperature to transform it into a superconducting state, and the internal space of the structure is magnetically shielded.

However, such a structure must be provided with an opening for the entry and exit of people and the loading and unloading of equipment, which is favorable because of the magnetic field penetrating into the interior from the opening. Since no effective shielding effect is obtained, precise magnetic measurement inside the magnetic shield structure becomes impossible.

Therefore, a cylindrical structure having a very large length with respect to the opening diameter is required. For example, in order to obtain a magnetically shielded space having a shielding rate of about 10 ⁻⁶ times against a magnetic field from each direction. Requires a cylindrical superconducting structure having one end closed at least 5 times the opening diameter, which requires a large space, and is difficult to manufacture, resulting in high cost.

Further, since it is difficult to provide a door with a superconductor in order to obtain a space with less magnetic noise by the superconductor, a structure as shown in FIG. 11 attached heretofore has been proposed. However, as shown in FIG. 11, the space that is not originally required becomes large, and therefore a large amount of expensive superconducting material is required, resulting in an increase in cost and a reduction in the degree of freedom in the installation space of the magnetic shield room. there were.

Further, when the originally required magnetic shield space is narrowed and is intended to be wide, the originally unnecessary space portion must be widened at the same ratio, and the area of the unnecessary space portion is considerably large. However, there is a problem that the entire structure cannot be compactly packed and stored in a limited narrow space.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and allows humans to move in and out and equipment to be carried in.
By blocking the effect of inevitable magnetic field coming in through the opening for carrying out, it is possible to realize a sophisticated magnetic shielded space that enables precise magnetic measurement inside the magnetic shield structure, and the entire structure is compact. In summary, it is an object of the present invention to provide a superconducting magnetic shield structure capable of housing the structure in a limited narrow space.

[0008]

According to a first aspect of the present invention, one end of a box made of a superconducting material having both ends opened is superconductingly coupled to the opening of a magnetic shield structure body having an opening made of a superconducting material. Is a superconducting magnetic shield structure, characterized in that it is integrated with the main body of the structure, and the inside is communicated,

According to a third aspect of the present invention, the magnetic shield structure main body having an opening made of a superconducting material is formed of a superconducting material having both ends opened, which is formed by sharing a part of the structure main body. A superconducting magnetic shield structure characterized in that one end of a box is superconductingly coupled to be integrated with the main body of the structure, and the inside is communicated.

In the invention according to claim 1, it is preferable that the box has a cylindrical shape or a rectangular tube shape.
In the invention of (1), it is preferable that the shape of the box is a plane arc shape or a rectangular tube shape.

[0011]

Next, the present invention will be described in detail. In the invention of claim 1, as shown in FIG. 1 and FIG. 2, human beings enter and leave the main body of the magnetic shield structure in which the upper and lower ends of a cylindrical or rectangular tube formed of a plate-shaped superconducting material are closed. An opening for loading and unloading of equipment is provided, and both ends are opened to the opening, and the ratio of the length (L) to the opening diameter (D: inner diameter in the case of a cylindrical shape, width in the case of a square tube). (L / D) is preferably 3 or more, and one end of a box formed of a plate-shaped superconducting material having a cylindrical shape (FIG. 1) or a rectangular tube shape (FIG. 2) is superconductingly coupled with a superconducting paste or the like. It is a superconducting magnetic shield structure which is integrated with the superconducting structure body and has the inside communicating with each other.

The shapes of the magnetic shield structure body and the box forming the above-mentioned superconducting magnetic shield structure are not limited to the cylindrical shape or the rectangular tube shape illustrated in FIGS. 1 and 2, but may be slightly modified. Of course, the shape of the cross section of each part may not be uniform. It suffices that the box shields the invasion of external magnetic fields and allows humans to enter and exit and equipment to be carried in and out.

In the superconducting magnetic shield structure constructed as described above, the intrusion of the external magnetic field from each direction is shielded by the structure body made of the superconducting material, the box body and the superconducting joint portion, and in particular, it should enter through the opening. The magnetic lines of force are shielded by a box made of a superconducting material as described later (FIG. 10), and the inside of the magnetic shield structure main body is completely magnetically shielded to obtain a high-level magnetic shielding space.

In the invention of claim 3, as illustrated in FIGS. 3 and 5, a human being is attached to the main body of the magnetic shield structure in which the upper and lower ends of a cylindrical or rectangular tube formed of a plate-shaped superconducting material are closed. And an opening for loading and unloading of equipment and a part of the main body of the structure are shared, and both ends are open, and the length (L) (in the case of a plane arc shape, an arc shape) The ratio of the length) to the width (D) of the opening (in the case of a rectangular tube shape or a plane arcuate shape, the cross-sectional lateral width is large), preferably 3 or more of a rectangular tube shape (FIG. 3) or a plane arc shape (FIG. ) Is a superconducting magnetic shield structure in which one end of the box formed of the superconducting material is superconductingly coupled to the opening with a superconducting paste or the like to be integrated with the main body of the structure, and the insides of both are connected to each other.

The shape of the magnetic shield structure body constituting the superconducting magnetic shield structure according to the third aspect of the invention is not limited to the cylindrical shape or the rectangular tube shape illustrated in FIGS. 3 and 5. Needless to say, the shape of the box body is not limited to the rectangular tube shape or the plane arc shape, and the cross-sectional shape of each part may not be uniform. Further, the magnetic shielding effect against the external magnetic field is similar to that of the invention of claim 1 above.

FIGS. 7 and 8 are explanatory views when an external magnetic field is applied to a superconducting magnetic shield structure in which a box is not continuously provided in the opening, and FIG. 7 is a superconducting magnetic shield in which no box is continuously provided. FIG. 8 is a perspective view of the structure body, and FIG. 8 shows a state of penetration of magnetic force lines when an external magnetic field (Hex) is applied to the structure body.

That is, in the superconducting magnetic shield structure, the external magnetic field (Hex) is shielded by the Meissner effect because the external magnetic field (Hex) cannot enter the structure from the portions other than the opening, but the leakage magnetic field leaks from the opening. The magnetic field lines penetrate into the main body of the magnetic shield structure, and the attenuation rate (Htr / Hex) is remarkably reduced particularly near the opening, and the magnetic shield effect inside the structure is hardly recognized.

FIGS. 9 and 10 are explanatory views when an external magnetic field is applied to a superconducting magnetic shield structure in which a rectangular cylindrical box body is superconductingly coupled to the opening, and FIG. 9 is a rectangular cylindrical shape at the opening. FIG. 10 is a perspective view of a superconducting magnetic shield structure in which a box is superconductingly coupled, and FIG. 10 shows a state of penetration of magnetic force lines when an external magnetic field (Hex) is applied to the superconducting magnetic shield structure.

That is, even if an external magnetic field (Hex) is applied to the main body of the superconducting magnetic shield structure, the box and the superconducting coupling portion in the same manner as described above, the superconducting electric current that cancels this flow without interruption and shields the external magnetic field (Hex). To do. However, a sneaking magnetic field tries to enter from the opening of the box,
When the L / D ratio of the box is at least 3 or more, the external magnetic field (Hex) is almost completely shielded, so that a high magnetic shielding space can be obtained in the magnetic shield structure body. Next, an embodiment of the present invention will be described with reference to the drawings.

[0020]

【Example】

Example 1 FIG. 1 shows an opening 4 on a side wall formed of a plate-shaped superconducting material.
Both ends of the magnetic shield structure main body 1 having closed cylindrical upper and lower ends are provided with the openings 4 and both ends thereof are opened, and the ratio (L / D) of the length (L) to the opening diameter (D) is large. One end (the left end in the figure) formed of a plate-shaped plate-shaped superconducting material is superconductingly coupled to the opening 4 of the magnetic shield structure body 1 with a superconducting paste to be integrated with the structure body 1. ,
This is a superconducting magnetic shield structure in which the structure body 1 and the inside of the box 2 communicate with each other. As the superconducting material, a well-known material having superconductivity at an extremely low temperature can be used.

Example 2 FIG. 2 shows an opening 4 formed on a side wall of a plate-shaped superconducting material.
Both ends are opened to the opening 4 of the main body 1 of the magnetic shield structure which is closed at the upper and lower ends of the rectangular cylindrical shape having a length (L).
And one end (the left end in the figure) of the box body 2 formed of a plate-shaped superconducting material in the shape of a rectangular tube having a large ratio (L / D) of the opening width (cross sectional width) (D) to the magnetic shield structure body 1 It is a superconducting magnetic shield structure in which the opening 4 is superconductingly coupled with a superconducting paste to be integrated with the structure body 1, and the structure body 1 and the inside of the box 2 communicate with each other. As the superconducting material, a known material having superconducting properties at an extremely low temperature can be used as in the first embodiment.

Embodiment 3 FIG. 3 shows an opening 4 is provided in the side wall A of a magnetic shield structure body 1 having a rectangular tubular shape formed of a plate-shaped superconducting material and having its upper and lower ends closed. Both ends formed by sharing the A side wall, which is a part, are opened, and the length (L) and the entrance / exit 5
Ratio (L / D) of lateral width (D) of the same shape and size as the opening 4
With a large superconducting material, one end of the box body 2 is superconductingly coupled to the opening 4 of the magnetic shield structure body 1 with a superconducting paste to be integrated with the structure body 1 and It is a superconducting magnetic shield structure in which the inside of the box 2 communicates. FIG. 4 is a view from the X, Y, and Z directions. The box 2 is formed by the A side wall, the B side wall, and the upper and lower wall surfaces, and is manufactured to have the same height as the structure body 1. As the superconducting material, the same material plate as in Examples 1 and 2 was used.

Embodiment 4 FIG. 5 is a perspective view of a superconducting magnetic shield structure, and FIG. 6 is a plan view thereof. In this embodiment, the cylindrical upper and lower ends made of a plate-shaped superconducting material are An opening 4 is provided in the side wall of the closed magnetic shield structure body 1, and both ends formed by sharing the side wall A having a plane arc shape, which is a part of the structure body 1, are opened to form a plane arc shape. Side wall length (L),
Superconducting one end of a planar arc-shaped box body 2 made of a superconducting material having a large ratio (L / D) with a width (D) between both side walls to an opening of the magnetic shield structure body 1 with a superconducting paste. It is a superconducting magnetic shield structure in which the structure body 1 and the inside of the box 2 are connected to each other and integrated with the structure body 1. The box 2 is formed by A and B side walls having a plane arc shape and upper and lower wall surfaces, and is manufactured to have the same height as the structure main body 1. As the superconducting material to be used, the same materials as those in Examples 1 to 3 were used.

After cooling the superconducting magnetic shield structures having L / D of 3 or more in Examples 1 to 4 described above with liquid nitrogen (77K), the superconducting magnetic shield structures were externally parallel and perpendicular to the central axis of the structure main body 1. A magnetic field was applied to measure the magnetic shielding characteristics.

As a result, a shielded space having an extinction ratio (Htr / Hex) of 10 ⁻⁶ or more was obtained inside each superconducting magnetic shield structure body 1.

[0026]

According to the present invention, the ratio (L) of the length (L) to the opening diameter (D) is set in the opening of the main body of the superconducting magnetic shield structure.
/ D) is preferably 3 or more in the form of a tubular or rectangular tubular superconducting box, the external magnetic field lines are indirectly weakened and the external magnetic field from the opening into the shield structure body. It is possible to shield the invasion of the air and to obtain a highly shielded space.

Moreover, according to the present invention, the entire structure can be compactly packed, and the structure can be housed in a limited narrow space.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a superconducting magnetic shield structure in which cylindrical boxes according to the present invention are combined.

FIG. 2 is a perspective view showing an embodiment of a superconducting magnetic shield structure in which rectangular tubular boxes according to the present invention are combined.

FIG. 3 is a perspective view showing an embodiment of a superconducting magnetic shield structure according to the present invention, in which a rectangular tubular box body sharing a part of the magnetic shield structure body is coupled.

FIG. 4 is a diagram showing X, of the superconducting magnetic shield structure shown in FIG.
It is an arrow view from the Y and Z directions.

FIG. 5 is a perspective view showing an embodiment of a superconducting magnetic shield structure according to the present invention, in which planar arc-shaped boxes sharing a part of the magnetic shield structure main body are combined.

FIG. 6 is a plan view of the superconducting magnetic shield structure shown in FIG.

FIG. 7 is a perspective view of a superconducting magnetic shield structure in which a box is not coupled to the opening of the magnetic shield structure body.

8 is an explanatory diagram of magnetic force lines when an external magnetic field is applied to the structure shown in FIG.

FIG. 9 is a perspective view of a superconducting magnetic shield structure in which a rectangular tubular box is coupled to the opening of the magnetic shield structure body.

FIG. 10 is an explanatory diagram of magnetic force lines when an external magnetic field is applied to the structure shown in FIG.

FIG. 11 is an explanatory cross-sectional view of a conventional magnetic shield structure.

[Explanation of symbols]

 1-Superconducting magnetic shield structure main body 2-Box 3-Superconducting coupling section 4-Aperture section 5-Inlet / outlet port 6-Magnetic field line A-Shared side wall B-Side wall D-Opening diameter or opening width L-Box length a − Superconducting magnetic shield space − Space not actually needed

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Sumio Mukaiyama, 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd. (72) Masahiro Kojima 1-2-8, Marunouchi, Chiyoda-ku, Tokyo Dowa Mining Co., Ltd. (72) Inventor Hideetsu Haseyama 1-2-8 Marunouchi, Chiyoda-ku, Tokyo Dowa Mining Co., Ltd.

Claims (4)

[Claims] 1. A magnetic shield structure body having an opening made of a superconducting material, wherein one end of a box made of a superconducting material whose both ends are open is superconductingly coupled to the opening so as to be integrated with the structure body and communicate with the inside. A superconducting magnetic shield structure characterized by being formed. 2. The superconducting magnetic shield structure according to claim 1, wherein the box has a cylindrical shape or a rectangular tube shape. 3. A magnetic shield structure main body having an opening made of a superconducting material, wherein one end of a box made of a superconducting material having both ends opened and formed by sharing a part of the structure main body is superconducting. A superconducting magnetic shield structure, characterized in that the superconducting magnetic shield structure is integrated with the structure body and communicates with the inside. 4. The superconducting magnetic shield structure according to claim 3, wherein the box has a plane arc shape or a rectangular tube shape.