JP2014157940A - Superconductive magnetic shield equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a superconductive magnetic shield equipment capable of achieving high magnetic shielding properties even if a tape-like superconductive wire material is used for it.SOLUTION: A superconductive magnetic shield equipment comprises: a first axial direction magnetic shield 12A and a second axial direction magnetic shield 12B having a superconductive material 15A for the first axial direction in which a tape-like superconductive material 21 having a first surface where a superconductive material layer 23 is thereon, and a second surface where the superconductive material layer 23 is not thereon, is formed in a ring shape; a lateral direction magnetic shield 13 having a superconductive material 16 for the lateral direction arranged orthogonally to or aslope to the axial direction of the second axial direction magnetic shield 12B and electrically connected to the second axial direction magnetic shield 12B; and a support body 11 for supporting magnetic shields 12A, 12B, 13, respectively. The second axial direction magnetic shield 12B is arranged at an outer periphery position of the first axial direction magnetic shield 12A, and the first axial direction magnetic shield 12A is configured that its first surface is positioned at the support body 11 side and the first surface of the second axial direction magnetic shield 12B is electrically connected to the lateral direction magnetic shield 13.

Description

  The present invention relates to a superconducting magnetic shield apparatus that performs magnetic shielding using a high-temperature superconductor.

  For example, a weak magnetic field measurement device that measures a weak magnetic field, such as a magnetoencephalograph or a magnetocardiograph, measures an external magnetic field such as geomagnetism as a disturbance. For this reason, the weak magnetic field measurement device is shielded by a magnetic shield device that shields the external magnetic field that becomes a disturbance so that the disturbance does not adversely affect the weak magnetic field measurement device, thereby measuring the weak magnetic field.

  Conventionally, as this magnetic shield device, there is one in which the entire inner wall of a room in which a weak magnetic field measuring device is installed is made of a magnetic shield material, and this magnetic shield room prevents the influence of an external magnetic field (see Patent Document 1). .

JP 2002-291713 A

  However, since the magnetic shield room is configured to magnetically shield the entire room, there is a problem that it becomes a large-scale facility.

  On the other hand, in recent years, tape-like superconducting wires have begun to be provided. It is desired to reduce the size and simplify the structure of the magnetic shield device by configuring the magnetic shield device using this tape-shaped superconducting wire.

  However, there are tape-shaped superconducting wires having various structures, and some are provided with a substrate containing a magnetic material (for example, RE123-based superconducting wires). When a superconducting magnetic shield is configured using such a tape-shaped superconducting wire, an improvement in the effect as a magnetic shield cannot be expected depending on the installation conditions.

  The present invention has been made in view of the above points, and an object thereof is to provide a superconducting magnetic shield device capable of realizing high magnetic shielding properties.

From a certain point of view,
A first axial magnetic shield having a first axial superconducting material formed in a ring shape from a tape-shaped superconducting material having a first surface on which a superconductor exists and a second surface on which the superconductor does not exist;
A tape-shaped superconducting material having a first surface on which a superconductor exists and a second surface on which the superconductor does not exist, and a second superconducting material formed in a ring shape; A second axial magnetic shield having a second axial superconducting material disposed at an outer peripheral position of the superconducting material;
A transverse magnetic shield having a superconducting material for transverse direction, which is disposed orthogonally or inclined with respect to the axial direction of the second axial magnetic shield and electrically connected to the second axial magnetic shield;
A support for supporting the first axial magnetic shield, the second axial magnetic shield, and the lateral magnetic shield;
The first axial magnetic shield is configured such that the first surface is located on the support side,
The second axial magnetic shield can be solved by a superconducting magnetic shield device characterized in that the first surface is positioned on the lateral magnetic shield side.

  According to the disclosed invention, even when a tape-shaped superconducting material having a first surface where a superconductor exists and a second surface where the superconductor does not exist is used, the shielding performance can be improved.

FIG. 1 is a perspective view of a superconducting magnetic shield device according to an embodiment of the present invention. FIG. 2 is a plan view of a superconducting magnetic shield device according to an embodiment of the present invention. FIG. 3 is an exploded perspective view of the superconducting magnetic shield device according to an embodiment of the present invention. FIG. 4 is an enlarged perspective view showing the first and second axial superconducting materials. FIG. 5 is an enlarged cross-sectional view showing the joining position of the first and second axial superconducting materials and the lateral superconducting material. FIG. 6 is a diagram showing a superconducting current generated in the axial superconducting material when an axial magnetic field is applied. FIG. 7 is a diagram showing a superconducting current generated between an axial superconducting material and a lateral superconducting material when a transverse magnetic field is applied. FIG. 8 is a diagram for explaining one configuration of the tape-shaped superconducting material.

  Next, embodiments of the present invention will be described with reference to the drawings.

  1 to 3 show a superconducting magnetic shield device 10 according to a first embodiment of the present invention. 1 is a perspective view of a superconducting magnetic shield device 10, FIG. 2 is a plan view, and FIG. 3 is an exploded perspective view. The superconducting magnetic shield device 10 is applied to a weak magnetic field measuring device that measures a weak magnetic field such as a magnetoencephalograph or a magnetocardiograph.

  The superconducting magnetic shield device 10 includes a support 11, a first axial magnetic shield 12A, a second axial magnetic shield 12B, a lateral magnetic shield 13, and the like. In the present embodiment, the support 11, the first axial magnetic shield 12A, the second axial magnetic shield 12B, and the lateral magnetic shield 13 are arranged in order from the innermost periphery. Therefore, the superconducting magnetic shield device 10 has a structure in which the support 11, the magnetic shields 12A and 12B in the axial direction, and the magnetic shield 13 in the lateral direction are overlapped in quadruplicate.

  The superconducting magnetic shield device 10 has a cylindrical shape as a whole. Therefore, a magnetic field shielding space portion 14 (hereinafter, simply referred to as a space portion 14) is formed in the central portion, and when the superconducting magnetic shield device 10 is applied to a magnetoencephalograph, the brain is placed inside the space portion 14. A magnetometer is provided, and the head of a person to be measured is inserted.

  Hereinafter, each component which comprises the superconducting magnetic shield apparatus 10 is demonstrated.

  First, the support 11 will be described. The support 11 has a cylindrical shape and supports the axial magnetic shields 12 </ b> A and 12 </ b> B and the lateral magnetic shield 13. The material of the support 11 is not particularly limited, but in the present embodiment, a resin or metal that is nonmagnetic and has good moldability is used. In addition, a cooling pipe (not shown) through which a coolant for cooling magnetic shields 12A, 12B, and 13 to be described later flows is disposed on the inner periphery of the support 11.

  The first axial magnetic shield 12A and the second axial magnetic shield 12B shield against an axial magnetic field.

  In this specification, the magnetic field in the axial direction of the cylinder (directions indicated by arrows Z1 and Z2 in the figure) is called the axial magnetic field, and the magnetic field in the direction orthogonal to the axial direction of the cylinder is called the transverse magnetic field. . A magnetic shield against an axial magnetic field is called an axial magnetic shield, and a magnetic shield against a transverse magnetic field is called a transverse magnetic shield. Moreover, the magnetic field applied from directions other than an axial direction or a horizontal direction can be decomposed | disassembled into an axial direction magnetic field and a horizontal direction magnetic field. For this reason, in the following description, only an axial magnetic field and a transverse magnetic field will be described.

  The first axial magnetic shield 12A is composed of a plurality of first axial superconducting materials 15A, and the second axial magnetic shield 12B is composed of a plurality of second axial superconducting materials 15B.

  FIG. 4 shows an enlarged pair of corresponding first and second axial superconducting materials 15A and 15B. In addition, the figure shows a state in which a pair of first and second axial superconducting materials 15A and 15B are stacked in two stages.

  The first and second axial superconducting materials 15A and 15B are both configured by bending the tape-shaped superconducting material 21 into a ring shape (annular shape). Further, since the first and second axial superconducting materials 15A and 15B are formed by forming the tape-shaped superconducting material 21 into a ring shape, both end portions thereof are in an attached state. Hereinafter, a portion where both ends of the first axial superconducting material 15A are attached is referred to as a first end 17A, and a portion where both ends of the second axial superconducting material 15B are attached is a second end. 17B (see FIG. 4).

  The first end 17A and the second end 17B are joined by a conductive joining material such as solder. Accordingly, the axial superconducting materials 15A and 15B constituting the axial magnetic shields 12A and 12B constitute a one-turn coil.

  FIG. 8 is an enlarged view showing the tape-shaped superconducting material 21 constituting the first axial superconducting material 15A and the second axial superconducting material 15B.

  The tape-shaped superconducting material 21 is configured such that a superconducting material layer 23, a substrate 24, and the like are laminated from the first surface (front surface) side to the second surface (back surface). That is, the superconducting material layer 23 is located on the first surface side, and the substrate 24 is located on the second surface side. In FIG. 8, only the main structure of the tape-shaped superconducting material 21 is shown.

The superconducting material layer 23 is, for example, an RE-based superconductor (RE: rare earth element) that exhibits a superconducting phenomenon at a liquid nitrogen temperature (77 K) or higher, particularly a RE-based superconductor represented by a composition formula of REBa ₂ Cu ₃ O ₇ -δ. ((RE) BCO) can be used.

  The substrate 24 is provided so that the tape-shaped superconducting material 21 maintains mechanical strength. At the time of manufacturing the tape-shaped superconducting material 21, the substrate 24 also functions as a base material for forming the superconducting material layer 23. As the substrate 24, for example, a Ni alloy (Hastelloy; registered trademark) having good mechanical characteristics and thermal characteristics is generally used. This Hastelloy is a low magnetic metal substrate and a material with low conductivity. For example, FYSC-SC05 (model number) manufactured by Fujikura Co., Ltd. can be used as the tape-shaped superconducting material 21 configured as described above.

  The tape-shaped superconducting material 21 configured as described above has a higher mechanical strength and is more resistant to strain than a superconducting material alone. For this reason, even if the tape-shaped superconducting material 21 is formed in a loop shape as shown in FIG. 4, the high-temperature superconducting material is not damaged by the distortion, and the yield can be improved. Further, by using the tape-shaped superconducting material 21, the handling of the axial superconducting materials 15A and 15B is facilitated, and the assembly work of the first axial magnetic shields 12A and 12B can be easily performed.

  Next, the transverse magnetic shield 13 will be described.

  Unlike the axial magnetic shields 12A and 12B, the lateral magnetic shield 13 is linear. Therefore, the axial magnetic shields 12A and 12B and the horizontal magnetic shield 13 are configured to extend in directions orthogonal to each other, as shown in FIGS.

  Moreover, in this embodiment, it is comprised so that the longitudinal direction of each superconducting material 16 for each horizontal direction may become parallel to an axial direction. Furthermore, the superconducting material 16 for the lateral direction is disposed so as to surround the outer peripheral position of the cylindrical second magnetic shield 12B.

  As shown in an enlarged view in FIG. 5, each lateral superconducting material 16 is joined to the second axial superconducting material 15 </ b> B constituting the second axial magnetic shield 12 </ b> B located outside by using solder 19. Is done. Thus, the second axial superconducting material 15B and the lateral superconducting material 16 are configured such that the second axial magnetic shield 12B and the lateral magnetic shield 13 are electrically connected.

  Next, the operation when a magnetic field is applied from the outside in the superconducting magnetic shield device 10 having the above configuration will be described with reference to FIGS.

As shown in FIG. 6, when an axial magnetic field (B _A ) is applied to the superconducting magnetic shield device 10, the first axial magnetic shield 12A is mainly used in the configuration of this embodiment as will be described later. Function. That is, when an axial magnetic field (B _A ) is applied, a superconducting current A is generated in the superconducting material layer 23 of the superconducting material 15A for the axial direction close to the space 14 in the circumferential direction, whereby the axial magnetic field (B _A ) can be prevented from affecting the space 14.

On the other hand, as shown in FIG. 7, when a transverse magnetic field (B _S ) is applied to the superconducting magnetic shield device 10, the transverse magnetic shield 13 functions. That is, when the horizontal direction magnetic field (B _S) is applied, the provided is axial superconducting material 15B (15A) and lateral superconductive material 16 on the outside, application of a transverse magnetic field (B _S) A superconducting current A that flows in the circular direction around the position is generated.

The axial superconducting material 15B of the second axial magnetic shield 12B located on the outside is electrically connected to the lateral superconducting material 16 by joining with a solder 19 (see FIG. 5). Therefore supercurrent A generated in the horizontal direction magnetic field (B _S) flows across the superconducting material layer 23 in the axial and lateral tape-like superconducting material 15B, 16, thereby the horizontal direction magnetic field (B _S) is the space 14 can be prevented from being affected.

  By the way, the tape-shaped superconducting material 21 used in this embodiment has different characteristics on the first surface (front surface) and the second surface (back surface) as described above. For this reason, when the tape-shaped superconducting material 21 is used as the first and second axial magnetic shields 12A and 12B, the shield of the superconducting magnetic shield device 10 depends on the orientation of the first surface and the second surface of the tape-shaped superconducting material 21. It is possible to influence the characteristics.

  That is, the substrate 24, which is a low magnetic metal base material, is configured to face the magnetic field shielding space, a phenomenon in which a magnetic field is sucked into the substrate 24 occurs, and the second surface side on which the substrate 24 is disposed is on the magnetic field shielding space side ( If the first axial magnetic shield 12A is arranged so that the support 11 side is directed and the first surface side on which the superconducting material layer 23 is disposed faces outward, the magnetic shielding effect of the superconducting magnetic shield device 10 is reduced. It is because it ends up.

  For this reason, in the present embodiment, the first axial magnetic shield 12A is disposed so that the first surface side (side on which the superconducting material layer 23 is disposed) is located on the magnetic field shielding space side (support 11 side). . Specifically, the tape-shaped superconducting material 21 is formed so that the first surface side on which the superconducting material layer 23 is disposed is outside, and the first superconducting material 15A for the axial direction is formed by forming this into a ring shape. Formed.

  In the first axial magnetic shield 12A having the first axial superconducting material 15A configured as described above, when an external magnetic field enters the space 14, the superconducting material layer 23 is reduced in the direction in which the external magnetic field is reduced. A superconducting current is generated. Further, since the low magnetic substrate 24 is located on the outside, the phenomenon that the external magnetic field is sucked into the substrate 24 does not occur. Therefore, according to the configuration of the present embodiment, the magnetic shield effect of the superconducting magnetic shield device 10 can be improved.

On the other hand, when the first axial magnetic shield 12A is configured as described above, the non-conductive substrate 24 is located outside. Therefore, even if the lateral superconducting material 16 is directly disposed on the second surface of the first axial magnetic shield 12A, the plurality of lateral superconducting materials 16 cannot be electrically connected. A shielding effect against the transverse magnetic field (B _S ) cannot be expected.

  Thus, in the present embodiment, the second axial magnetic shield 12B made of the tape-shaped superconducting material 21 is provided outside the first axial magnetic shield 12A. The second axial magnetic shield 12B is configured such that the first surface on which the superconducting material layer 23 is provided is on the outside (side facing the lateral superconducting material 16).

Therefore, the lateral superconducting material 16 is joined to the first surface of the second axial magnetic shield 12B by using the solder 19 so that each lateral superconducting material 16 becomes the second axial magnetic shield 12B. It becomes the structure electrically connected through the superconducting material layer 23. As a result, even if a superconducting current is generated by the transverse magnetic field (B _S ), the superconducting current flows across the superconducting material layer 23 of the axial and transverse tape-like superconducting materials 15B, 16; The influence of B _S ) can be reliably reduced.

  Here, attention is paid to a position where the first axial magnetic shield 12A disposed on the inner side and the second axial magnetic shield 12B disposed on the outer side face each other.

  As described above, the outside of the first axial magnetic shield 12A is the second surface on which the substrate 24 is disposed. The inner side of the second axial magnetic shield 12B is also a second surface on which the substrate 24 is disposed. Therefore, it is difficult to electrically connect the first axial magnetic shield 12A and the second axial magnetic shield 12B.

  However, in order to enhance the shielding effect in the space 14, it is desirable to electrically connect the plurality of first axial superconducting materials 15A. Therefore, in the superconducting magnetic shield device 10 according to the present embodiment, as shown in FIGS. 2 and 4, the insides of the plurality of first axial superconducting materials 15 </ b> A are electrically connected using the connecting superconducting wire 30. It is configured. The connecting superconducting wire 30 is preferably a non-magnetic material because it is a superconducting material and is disposed in the space 14. Examples of this material include DI-BSCCO manufactured by Sumitomo Electric Industries, Ltd.

In this way, by configuring the plurality of first axial superconducting materials 15A to be connected by the connecting superconducting wire 30, the influence of the axial magnetic field (B _A ) acting in the space portion 14 is reliably reduced. Can be made.

  It is desirable that the connection position of the connecting superconducting wire 30 is set to the position where the first end portion 17A having high electrical resistance is formed in the first axial superconducting material 15A. By adopting this configuration, since the superconducting current generated in the first axial superconducting material 15A flows bypassing the connecting superconducting wire 30, the electrical resistance at the first end 17A is substantially reduced, Therefore, the shielding effect can be enhanced.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments described above, and various modifications are possible within the scope of the gist of the present invention described in the claims. It can be modified and changed.

10 Superconducting Magnetic Shield Device 11 Support 12A First Axial Magnetic Shield 12B Second Axial Magnetic Shield 13 Lateral Magnetic Shield 14 Space 15A First Axial Superconducting Material 15B Second Axial Superconducting Material 16 Superconducting material for lateral direction 17A First end portion 17B Second end portion 18, 19 Solder 21 Tape-shaped superconducting material

Claims (3)

A first axial magnetic shield having a first axial superconducting material formed in a ring shape from a tape-shaped superconducting material having a first surface on which a superconductor exists and a second surface on which the superconductor does not exist;
A tape-shaped superconducting material having a first surface on which a superconductor exists and a second surface on which the superconductor does not exist, and a second superconducting material formed in a ring shape; A second axial magnetic shield having a second axial superconducting material disposed at an outer peripheral position of the superconducting material;
A transverse magnetic shield having a superconducting material for transverse direction, which is disposed orthogonally or inclined with respect to the axial direction of the second axial magnetic shield and electrically connected to the second axial magnetic shield;
A support for supporting the first axial magnetic shield, the second axial magnetic shield, and the lateral magnetic shield;
The first axial magnetic shield is configured such that the first surface is located on the support side,
The superconducting magnetic shield device, wherein the second axial magnetic shield is configured such that the first surface is located on the lateral magnetic shield side.   2. The superconducting magnetic shield device according to claim 1, wherein the tape-shaped superconducting material has a substrate on the second surface side. A first axial magnetic shield is composed of a plurality of the first axial superconductors,
The superconducting magnetic shield device according to claim 1 or 2, wherein the plurality of first axial superconducting materials are electrically connected by a connecting superconducting wire made of a nonmagnetic material.

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