JP7128470B2 - Inspection apparatus and inspection method for cylindrical superconductor - Google Patents

Description

The present invention relates to an inspection apparatus and inspection method for cylindrical superconductors.

Development of a compact superconducting magnet for NMR using a superconducting bulk magnet obtained by magnetizing a bulk (mass) superconductor to capture a magnetic field is underway. For example, Patent Literature 1 discloses a superconducting magnet (magnetic field generator) in which a cylindrical inner superconductor is coaxially arranged inside a cylindrical outer superconductor. According to the superconducting magnet described in Patent Document 1, the outer superconductor and the inner superconductor are cooled to a superconducting critical temperature (Tc) or less in a state in which a uniform external magnetic field is applied in the central axis direction, and then , zero the applied magnetic field. As a result, the superconductor is magnetized and a uniform magnetic field space is formed in the bore (inner circumferential space) of the outer superconductor. At this time, a superconducting current is induced in the cylindrical circumferential surface of the inner superconductor so as to compensate for the applied magnetic field distribution that the outer superconductor could not hold. That is, the inner superconductor is magnetized so as to compensate for the disturbance of the magnetic field produced by the outer superconductor. This creates a more uniform magnetic field in the bore. By inserting a measurement sample and a measurement probe into a bore in which a uniform magnetic field is formed and obtaining an NMR spectrum from the signal detected by the measurement probe, structural analysis of the sample can be performed with relatively high accuracy.

In the cylindrical inner superconductor described in Patent Document 1, a supercurrent flows in the cylindrical peripheral surface as described above. Therefore, when the soundness of the superconducting state inside the cylindrical peripheral surface is damaged due to defects in the cylindrical peripheral surface, there are cases where the desired superconducting current cannot be formed in the cylindrical peripheral surface. can occur. In this case, the inner superconductor cannot sufficiently compensate the disturbance of the magnetic field produced by the outer superconductor. Therefore, it is preferable that the soundness of the superconducting state of the inner superconductor is good, and it is necessary to inspect in advance whether the soundness of the superconducting state of the inner superconductor is good.

However, conventionally, an inspection apparatus and an inspection method capable of inspecting the soundness of the superconducting state of such a cylindrical superconductor have not been developed. Non-Patent Document 1 describes a method for inspecting the magnetic field state of a superconducting wire, but does not mention an inspection apparatus and inspection method for a cylindrical superconductor. It is unclear how the method may be applied to cylindrical superconductors.

JP-A-2016-6826

Applied Physics Letters 90, 032506(2007),"Assessment of the local supercurrent densities in long superconducting coated conductors", M. Zehetmayer, R. Fuger, M. Eistere, F. Hengstberger, and H. W. Weber

(Problems to be solved by the invention)
SUMMARY OF THE INVENTION An object of the present invention is to provide an inspection apparatus and an inspection method capable of inspecting the soundness of the superconducting state of a cylindrical superconductor.

(means to solve the problem)
In the present invention, a shielding magnetic field detection sensor (53) arranged facing the cylindrical peripheral surface of a cylindrical superconductor (7) brought into a superconducting state and moving the shielding magnetic field detection sensor along the axial direction of the cylindrical superconductor. and a rotation unit (30) configured to rotate the shielding magnetic field detection sensor around the central axis of the cylindrical superconductor. It has two magnetic poles (N pole, S pole), one magnetic pole is arranged at a position facing the cylindrical peripheral surface of the cylindrical superconductor with the shielding magnetic field detection sensor interposed, and is movably shielded together with the shielding magnetic field detection sensor a magnet (55) connected to the magnetic field detection sensor, wherein the magnetic field applied from one magnetic pole of the magnet to the cylindrical superconductor is shielded by the cylindrical surface of the cylindrical superconductor. The superconducting state within the cylindrical surface of the cylindrical superconductor is detected by moving along the cylindrical surface of the cylindrical superconductor by driving the axially moving unit and the rotating unit. Provided is an inspection apparatus (1) for a cylindrical superconductor, which is configured to inspect the soundness of a cylindrical superconductor.

Cooling the cylindrical superconductor below its superconducting critical temperature Tc renders the cylindrical superconductor superconducting. When a magnetic field is applied by bringing one magnetic pole of a magnet close to the cylindrical surface of a cylindrical superconductor that has been brought into a superconducting state, a superconducting current (shielding current ) is induced. This shielding current shields the applied magnetic field from entering the cylindrical superconductor. This shielding of the applied magnetic field eliminates the magnetic field from the space between the cylindrical superconductor and the magnet. Therefore, the magnetic field (shielding magnetic field) formed between the cylindrical superconductor and the magnet is weakened. However, if a defect exists on the cylindrical surface of the cylindrical superconductor, the applied magnetic field penetrates the cylindrical superconductor through the defective portion because the shielding current is not sufficiently induced at that portion. When the applied magnetic field passes through the cylindrical superconductor in this way, the magnetic field enters between the cylindrical superconductor and the magnet, so that the shielding magnetic field becomes stronger. Also, if there is a location where the critical current density Jc, which is one of the superconducting properties of a superconductor, is locally weak, the shielding current will decrease, which will also increase the shielding magnetic field. Therefore, by detecting the shielding magnetic field along the cylindrical surface of the cylindrical superconductor, the soundness of the superconducting state (existence of defects, variations in critical current density, etc.) within the cylindrical surface of the cylindrical superconductor can be inspected. can do.

According to the present invention, the shielding magnetic field detection sensor is arranged to face the cylindrical peripheral surface of the cylindrical superconductor, and one magnetic pole faces the cylindrical peripheral surface of the cylindrical superconductor with the shielding magnetic field detection sensor interposed therebetween. A magnet is placed in the Therefore, the shielding magnetic field detection sensor detects a shielding magnetic field formed by shielding the magnetic field applied from the magnet by the cylindrical peripheral surface of the cylindrical superconductor. In the inspection apparatus according to the present invention, the shielding magnetic field detection sensor detects the shielding magnetic field while moving along the cylindrical peripheral surface of the cylindrical superconductor by driving the axially moving unit and the rotating unit. Therefore, it is possible to inspect the soundness of the superconducting state within the cylindrical circumferential surface of the cylindrical superconductor.

In the present invention, inspecting the soundness of the superconducting state is used in the sense of inspecting whether or not a cylindrical superconductor can uniformly form a shielding current (superconducting current) in the cylindrical peripheral surface. . The soundness of the superconducting state is evaluated by the uniformity of the shielding magnetic field detected by the shielding magnetic field sensor along the cylindrical circumferential surface of the cylindrical superconductor or the transmission magnetic field described later. It is represented by the presence or absence of change in the magnitude of the magnetic field or the magnitude of the penetrating magnetic field. Specifically, if a region with a weak shielding magnetic field (or permeation magnetic field) continues, it can be determined that the superconducting state is healthy (that is, a uniform shielding current can be formed), and the shielding magnetic field (or permeation magnetic field) is strong. If there is an area, it can be determined that the superconducting state is unhealthy (that is, the shielding current cannot be formed uniformly) due to the existence of a defect or a decrease in the critical current density. Therefore, when the shielding magnetic field (transmission magnetic field) is uniformly weak (small) along the cylindrical surface of the cylindrical superconductor, it can be evaluated that the superconducting state of the cylindrical superconductor is uniformly sound. In addition, if there is a region where the shielding magnetic field (transmission magnetic field) is locally strong (large), by specifying the locally strong region, the presence and position of the defect, or the difference in the critical current density Jc depending on the location can be detected.

Further, according to the present invention, since the magnetic field (shielding magnetic field) weakened by the shielding current of the cylindrical superconductor is detected, the soundness of the superconducting state of the surface of the cylindrical peripheral surface facing the magnet can be effectively inspected. can do.

The area of the area where the shielding magnetic field detection sensor (specifically, the magnetic sensing part of the shielding magnetic field detection sensor) faces the cylindrical peripheral surface of the cylindrical superconductor is the area where the magnet sandwiches the shielding magnetic field detection sensor and the cylinder of the cylindrical superconductor. It is preferably smaller than the area of the region facing the peripheral surface. According to this, the inspection accuracy can be improved by reducing the area of the shielding magnetic field detected by the shielding magnetic field detection sensor.

As an example, the magnet and the shielding magnetic field detection sensor are arranged in the inner peripheral space of the cylindrical superconductor, as shown in the fourth embodiment described later. In this case, the shielding magnetic field detection sensor is arranged to face the inner peripheral surface of the cylindrical superconductor, and one of the magnetic poles of the magnet faces the inner peripheral surface of the cylindrical superconductor with the shielding magnetic field detection sensor interposed therebetween. be. With this configuration, it is possible to inspect the soundness of the superconducting state mainly on the surface of the inner circumference of the cylindrical superconductor. Moreover, since the shielding magnetic field detection sensor and the magnet are arranged in the inner peripheral space of the cylindrical superconductor, the inspection apparatus can be made compact. Therefore, when inspecting the soundness of a cylindrical superconductor incorporated in a superconducting magnet for NMR, for example, the inspection can be performed while the cylindrical superconductor is incorporated in the superconducting magnet.

When the shielding magnetic field detection sensor is arranged in the inner peripheral space of the cylindrical superconductor, the shielding magnetic field detection sensor is a first sensor (43A) and a second sensor ( 43B). In this case, one magnetic pole (for example, N pole) of the magnet is arranged to face the inner peripheral surface of the cylindrical superconductor with the first sensor interposed therebetween, and the other magnetic pole (for example, S pole) of the magnet is arranged with the second sensor interposed therebetween. It is preferable to arrange at a position facing the inner peripheral surface of the cylindrical superconductor. The first sensor detects a shielding magnetic field formed by shielding the magnetic field applied from one magnetic pole to the cylindrical superconductor by the cylindrical peripheral surface of the cylindrical superconductor, and the second sensor detects the other magnetic field. It is preferable to detect a shielding magnetic field formed by shielding the magnetic field applied to the cylindrical superconductor from the magnetic poles of the cylindrical superconductor by the cylindrical peripheral surface of the cylindrical superconductor. Also, the first sensor and the second sensor may be arranged at positions different from each other by 180° in the circumferential direction of the cylindrical superconductor. According to this, two places on the inner peripheral surface of the cylindrical superconductor can be inspected at the same time, so that the inspection time can be shortened.

As another example, the magnet and the shielding magnetic field detection sensor may be arranged in the outer peripheral space of the cylindrical superconductor as shown in the first embodiment described later. In this case, the shielding magnetic field detection sensor is arranged to face the outer peripheral surface of the cylindrical superconductor, and one of the magnetic poles of the magnet is arranged to face the outer peripheral surface of the cylindrical superconductor with the shielding magnetic field detection sensor interposed therebetween. be. According to this, it is possible to inspect the soundness of the superconducting state mainly on the surface of the outer circumference of the cylindrical superconductor.

In addition, the present invention provides a transmission magnetic field detection sensor (43) arranged facing the cylindrical peripheral surface of the cylindrical superconductor (7) in a superconducting state, and a transmission magnetic field detection sensor along the axial direction of the cylindrical superconductor. an axial movement unit (20) configured to move, a rotation unit (30) configured to rotate the transmitted magnetic field detection sensor around the central axis of the cylindrical superconductor; It has two different magnetic poles (N pole, S pole), and one magnetic pole is disposed at a position facing the permeation magnetic field detection sensor across the cylindrical surface of the cylindrical superconductor, and is movable together with the permeation magnetic field detection sensor. and a magnet (55) connected to a transmission magnetic field detection sensor in the transmission magnetic field detection sensor, the magnetic field applied from one magnetic pole of the magnet to the cylindrical superconductor is transmitted through the cylindrical surface of the cylindrical superconductor. Superconductivity within the cylindrical surface of the cylindrical superconductor is detected by moving along the cylindrical surface of the cylindrical superconductor by driving the axially moving unit and the rotating unit. An inspection apparatus (1) for a cylindrical superconductor is provided, which is configured to be able to inspect the soundness of the state.

As described above, when a magnetic field is applied by bringing one of the magnetic poles of the magnet close to the cylindrical surface of the cylindrical superconductor in a superconducting state, the applied magnetic field is shielded by the cylindrical surface of the cylindrical superconductor due to the shielding current. . However, as the applied magnetic field increases, part of the applied magnetic field penetrates the cylindrical surface of the cylindrical superconductor. However, the magnetic field created by this penetration (transmission magnetic field) is weak if the superconducting state of the cylindrical superconductor is healthy. However, if a defect exists on the cylindrical surface of the cylindrical superconductor, the applied magnetic field penetrates the cylindrical superconductor through the defective portion because the shielding current is not sufficiently induced at that portion. When the applied magnetic field penetrates the cylindrical superconductor in this manner, the transmitted magnetic field becomes stronger. Also, if there is a location where the critical current density Jc, which is one of the superconducting properties of a superconductor, is locally weak, the shielding current will decrease, which will also increase the permeation magnetic field. Therefore, by detecting the magnetic field transmitted along the cylindrical surface of the cylindrical superconductor, the soundness of the superconducting state (existence of defects, variations in critical current density Jc, etc.) in the cylindrical surface of the cylindrical superconductor can be determined. can be inspected.

According to the present invention, the transmission magnetic field detection sensor is arranged to face the cylindrical peripheral surface of the cylindrical superconductor, and one magnetic pole faces the transmission magnetic field detection sensor across the cylindrical peripheral surface of the cylindrical superconductor. A magnet is placed at the position. In other words, the permeation magnetic field detection sensor and the magnet are arranged to face each other with the cylindrical peripheral surface of the cylindrical superconductor sandwiched therebetween. Therefore, the transmission magnetic field detection sensor detects a transmission magnetic field formed by the magnetic field applied from the magnet passing through the cylindrical peripheral surface of the cylindrical superconductor. In the inspection apparatus according to the present invention, the transmission magnetic field detection sensor detects the transmission magnetic field while moving along the cylindrical peripheral surface of the cylindrical superconductor by driving the axial movement unit and the rotation unit. Therefore, it is possible to inspect the soundness of the superconducting state within the cylindrical circumferential surface of the cylindrical superconductor. Further, by detecting the magnetic field passing through the cylindrical surface of the cylindrical superconductor, the soundness of the superconducting state over the entire thickness direction of the cylindrical superconductor can be inspected.

The area of the region where the penetrating magnetic field detection sensor (specifically, the magnetic sensing part of the penetrating magnetic field detection sensor) faces the cylindrical peripheral surface of the cylindrical superconductor is the area where the magnet faces the cylindrical peripheral surface of the cylindrical superconductor. It is preferably smaller than the area. According to this, the inspection accuracy can be improved by reducing the transmission magnetic field area detected by the transmission magnetic field detection sensor.

As an example, the penetrating magnetic field detection sensor is arranged in the inner peripheral space of the cylindrical superconductor, as shown in the first embodiment described later. In this case, the transmission magnetic field detection sensor is arranged to face the inner peripheral surface of the cylindrical superconductor, and the magnet is cylindrical so that one magnetic pole faces the transmission magnetic field detection sensor across the cylindrical peripheral surface of the cylindrical superconductor. It is arranged facing the outer peripheral surface of the superconductor. With this configuration, it is possible to inspect the soundness of the superconducting state mainly on the surface of the inner circumference of the cylindrical superconductor.

Further, as another example, the transmission magnetic field detection sensor may be arranged in the outer peripheral space of the cylindrical superconductor, as shown in Modified Example 2 which will be described later. In this case, the transmission magnetic field detection sensor is arranged to face the outer peripheral surface of the cylindrical superconductor, and the magnet is a cylindrical superconducting magnet so that one magnetic pole faces the transmission magnetic field detection sensor across the cylindrical peripheral surface of the cylindrical superconductor. It is arranged facing the inner peripheral surface of the body. According to this, it is possible to inspect the soundness of the superconducting state mainly on the surface of the outer circumference of the cylindrical superconductor.

Also, a yoke (46) may be provided on the rear surface of the transmitted magnetic field detection sensor. According to this, the detection sensitivity of the transmission magnetic field detection sensor is improved by concentrating the transmission magnetic field on the yoke.

In addition to the transmission magnetic field detection sensor, the inspection apparatus of the present invention is arranged between the magnet and the cylindrical superconductor, and is arranged to face the transmission magnetic field detection sensor with the cylindrical peripheral surface of the cylindrical superconductor interposed therebetween. , a shielding magnetic field detection sensor (53) configured to be movable together with the transmission magnetic field detection sensor by driving the axial movement unit and the rotation unit. Then, the shielding magnetic field detection sensor detects a shielding magnetic field formed by shielding the magnetic field applied from one magnetic pole of the magnet to the cylindrical superconductor by the cylindrical peripheral surface of the cylindrical superconductor. The soundness of the superconducting state within the cylindrical circumferential surface of the cylindrical superconductor may be inspected by detecting while moving along the cylindrical circumferential surface of the cylindrical superconductor by driving the rotating unit. According to this, the penetrating magnetic field and the shielding magnetic field can be detected at the same time, and the inspection accuracy is further improved.

Also, the magnet used in the inspection apparatus according to the present invention may be a permanent magnet. By using a permanent magnet, an applied magnetic field can be formed without the need for incidental equipment such as a power source. Therefore, the structure of the inspection device can be simplified.

Also, the magnet used in the inspection device according to the present invention may be a coil or an electromagnet. By using a coil or an electromagnet, it is possible to change the magnitude and direction of the current applied to it, thereby changing the magnitude and direction of the magnetic field applied to the cylindrical superconductor. Therefore, the applied magnetic field can be adjusted to set optimum inspection conditions.

The cylindrical superconductor is formed in a cylindrical shape by spirally winding a cylindrical base material (71) and a superconducting wire around the inner or outer peripheral surface of the cylindrical base material. and superconducting layers (72, 73). In this case, the axial movement unit and the rotation unit are controlled so that the shielding magnetic field detection sensor and/or the transmission magnetic field detection sensor move along the cylindrical circumferential surface of the cylindrical superconductor along the spiral winding direction of the superconducting wire. good.

When inspecting the soundness of the superconducting state of the cylindrical surface of the cylindrical superconductor formed by spirally winding the superconducting wire, for example, first, the axial movement unit is driven to inspect the cylindrical superconductor along the axial direction. Then, the rotation unit is driven to rotate the inspection area by a predetermined angle. After that, the axial movement unit is driven to inspect the cylindrical superconductor along the axial direction. By repeating this, it is possible to inspect the entire cylindrical peripheral surface. However, in this case, it may be necessary to map the results of the inspection along the axial direction at each rotation angle in order to identify the location of the unhealthy portion. In contrast, by inspecting the cylindrical superconductor along the direction of the spiral winding as in the present invention, the rotation angle and the axial position change continuously, so the soundness of the superconducting state can be checked in real time without mapping. identification of sexuality and unhealthy areas can be performed.

In addition, the present invention has a shielding magnetic field detection sensor (53) arranged facing the cylindrical peripheral surface of the cylindrical superconductor (7) in a superconducting state, and two different magnetic poles (N pole, S pole). a sweeping step of sweeping a magnet (55) arranged at a position where the magnetic poles face the cylindrical peripheral surface of the cylindrical superconductor with the shielding magnetic field detection sensor interposed therebetween, in the axial direction and the circumferential direction of the cylindrical superconductor; While the shielding magnetic field detection sensor sweeps the shielding magnetic field formed by the magnetic field applied from one magnetic pole of the magnet to the cylindrical superconductor being shielded by the cylindrical peripheral surface of the cylindrical superconductor in a sweeping process and a shielding magnetic field detection step for detecting a cylindrical superconductor.

According to the inspection method of the present invention, the shielding magnetic field detection sensor detects the shielding magnetic field while being swept along the cylindrical peripheral surface of the cylindrical superconductor. Therefore, it is possible to inspect the soundness of the superconducting state within the cylindrical circumferential surface of the cylindrical superconductor.

In addition, the present invention has a transmission magnetic field detection sensor (43) arranged facing the cylindrical peripheral surface of the cylindrical superconductor (7) in a superconducting state, and two different magnetic poles (N pole, S pole). a sweeping step of sweeping a magnet (55) arranged at a position where the magnetic poles face a penetrating magnetic field detection sensor across the cylindrical peripheral surface of the cylindrical superconductor in the axial direction and the circumferential direction of the cylindrical superconductor; A transmission magnetic field detection sensor detects a transmission magnetic field formed by a magnetic field applied from one magnetic pole of a magnet to a cylindrical superconductor and transmitted through the cylindrical surface of the cylindrical superconductor while being swept in a sweeping process. and a penetrating magnetic field detection step for detecting a cylindrical superconductor.

According to the inspection method of the present invention, the penetrating magnetic field detection sensor detects the penetrating magnetic field while being swept along the cylindrical peripheral surface of the cylindrical superconductor. Therefore, it is possible to inspect the soundness of the superconducting state within the cylindrical circumferential surface of the cylindrical superconductor.

In the inspection method described above, the cylindrical superconductor is formed by spirally winding a cylindrical substrate (71) formed in a cylindrical shape and a superconducting wire on the inner or outer peripheral surface of the cylindrical substrate. and superconducting layers (72, 73) formed in a shape. In this case, in the sweeping step, the shielding magnetic field detection sensor and/or the permeation magnetic field detection sensor may be swept so as to move along the cylindrical peripheral surface of the cylindrical superconductor along the spiral winding direction of the superconducting wire. . According to this, it is possible to specify the soundness of the superconducting state of the cylindrical superconductor and the unsound portion in real time.

FIG. 1 is a schematic partial cross-sectional view showing a cylindrical superconductor inspection apparatus according to the first embodiment. FIG. 2 is a schematic cross-sectional view showing the connection configuration of the rotation unit, inner inspection unit, and outer inspection unit. FIG. 3 is a sectional view taken along line III--III in FIG. FIG. 4 is a schematic perspective view of a cylindrical superconductor. FIG. 5 is a schematic cross-sectional view of a cylindrical superconductor cut along a plane including its axial center. FIG. 6 shows separately the spirally wound inner superconducting layer and the outer superconducting layer. FIG. 7 is a schematic cross-sectional view of a container in which a cylindrical superconductor is arranged. FIG. 8 is a diagram showing the positional relationship between the cylindrical superconductor in the container and the inspection apparatus at the start of inspection. FIG. 9 is a schematic diagram showing the arrangement relationship of an inner Hall element, an outer Hall element, and an outer permanent magnet with respect to a cylindrical superconductor. FIG. 10 is a conceptual diagram showing the magnetic field detected by the outer Hall element. FIG. 11 is a conceptual diagram showing the magnetic field detected by the inner Hall element. FIG. 12 is a diagram conceptually showing the relationship between the shielding magnetic field detected by the outer Hall element and the presence or absence of defects in the cylindrical superconductor. FIG. 13 is a diagram conceptually showing the relationship between the transmitted magnetic field detected by the inner Hall element and the presence or absence of defects in the cylindrical superconductor. FIG. 14A shows a cylindrical superconductor with an inner superconducting layer and an outer superconducting layer that are intentionally defective. FIG. 14B is a diagram showing the unfolded state of the superconducting wire constituting the inner superconducting layer and the superconducting wire constituting the outer superconducting layer. FIG. 15 is a development view of a cylindrical body in which the inner superconducting layer and the outer superconducting layer are overlapped. FIG. 16 is a diagram showing measurement results of the shielding magnetic field detected by the outer Hall element. FIG. 17 is a diagram showing the measurement results of the transmitted magnetic field detected by the inner Hall element. FIG. 18 is a diagram showing the measurement results of the shielding magnetic field shown in FIG. 16 by mapping them onto a developed view of the cylindrical superconductor. FIG. 19 is a diagram showing the measurement result of the transmitted magnetic field shown in FIG. 17 by mapping it on a developed view of the cylindrical superconductor. FIG. 20 is a graph showing the relationship between the rotation angle and the strength of the magnetic field when the position of the cylindrical surface of the cylindrical superconductor formed by spirally winding the superconducting wire is represented by the rotation angle. 21 is a schematic cross-sectional view showing a connection configuration of a rotating unit, an inner inspection unit, and an outer inspection unit of an inspection apparatus according to Modification 2. FIG. FIG. 22 is a diagram showing the arrangement relationship between the inspection device and the cylindrical superconductor when the inspection device according to Modification 2 is used to inspect the cylindrical superconductor set in the container. FIG. 23 is a schematic diagram showing an example of spirally sweeping an outer Hall element having two Hall elements according to the second embodiment. FIG. 24 is a diagram showing the arrangement relationship between the outer Hall element and the inner superconducting layer and the outer superconducting layer of the cylindrical superconductor. FIG. 25 is a diagram showing a state in which a cylindrical superconductor cooled by a refrigerator is inspected by an inspection apparatus according to the third embodiment. FIG. 26 is a schematic diagram showing the arrangement relationship among a refrigerator, a cylindrical superconductor, an inner Hall element, an outer Hall element, and an outer permanent magnet. FIG. 27 relates to the fourth embodiment, and is a diagram showing a state in which a cylindrical superconductor incorporated in a superconducting magnet of an NMR apparatus is inspected by an inspection apparatus. FIG. 28 is a diagram showing a superconducting magnet incorporating a cylindrical superconductor. FIG. 29 is a diagram showing an example of inspection using the inspection apparatus according to the fifth embodiment. FIG. 30 is a diagram showing an example of inspection using the inspection apparatus according to the sixth embodiment. FIG. 31 is a diagram showing an example of inspection using the inspection apparatus according to the seventh embodiment. FIG. 32 is a diagram showing an example of inspection using the inspection apparatus according to the eighth embodiment. FIG. 33 is a diagram showing an example of inspection using the inspection apparatus according to the ninth embodiment.

(First embodiment)
A first embodiment of the present invention will be described below. FIG. 1 is a schematic partial cross-sectional view showing a cylindrical superconductor inspection apparatus (hereinafter simply referred to as an inspection apparatus) 1 according to the first embodiment. As shown in FIG. 1, the inspection apparatus 1 includes a manual elevation operation unit 10, an axial movement unit 20, a rotation unit 30, an inner inspection unit 40, an outer inspection unit 50, and a controller (not shown).

The manual lifting operation unit 10 has a support guide 11, an upper plate 12, a ball screw rod 13, a ball nut 14, and a manual handle 15, and is placed on a base plate P made of aluminum, for example.

The support guide 11 is a long plate-like member whose lower end is fixed to the base plate P and extends upward from the base plate P. As shown in FIG. A top plate 12 is fixed to the upper end of the support guide 11 . The upper plate 12 has a fixed portion 12a fixed to the support guide 11 and an extension portion 12b extending leftward in FIG. 1 from the fixed portion 12a. The upper end portion of the ball screw rod 13 is rotatably supported on the extended portion 12b of the upper plate 12. As shown in FIG. The ball screw rod 13 extends vertically downward from the upper plate 12 . A lower end of the ball screw rod 13 is rotatably supported by a bearing member (not shown) provided on the base plate P. As shown in FIG.

A male screw is formed on the outer circumference of the ball screw rod 13 . A ball nut 14 is attached to the outer periphery of the ball screw rod 13 so as to be screwed into a male thread formed on the outer periphery of the ball screw rod 13 so as not to rotate about the axis.

A manual handle 15 is provided above the top plate 12 . A manual handle 15 passes through the upper plate 12 and is connected to the upper end of the ball screw rod 13 . The manual handle 15 is rotatable about a vertical axis, and is configured to rotate the ball screw rod 13 about the axis. As the ball screw rod 13 rotates about its axis, the ball nut 14 screwed to the ball screw rod 13 moves up and down.

The axial movement unit 20 has a joint block 21 , a support case 22 , a first electric motor 23 , a ball screw rod 24 and an axial movement stage 25 .

The joint block 21 is connected to the ball nut 14 of the manual lifting operation unit 10 . A support case 22 is connected to the joint block 21 . The support case 22 has a lower plate 221 and support rods 222 . The support rod 222 extends vertically as shown in FIG. 1 and is connected to the joint block 21 at its lower portion. A lower plate 221 is fixed to the lower end of the support rod 222 . The lower plate 221 has a fixed portion 221a for fixing the support rod 222 and an extension portion 221b extending leftward in FIG. 1 from the fixed portion 221a.

A first electric motor 23 is fixed to the upper end of the support rod 222 . The first electric motor 23 is supported by the support rod 222 so that its output shaft faces downward. An upper end of a ball screw rod 24 is coaxially connected to the output shaft of the first electric motor 23 . Therefore, when the first electric motor 23 is driven, the ball screw rod 24 rotates about its axis. The lower end of the ball screw rod 24 is rotatably supported by the extending portion 221b of the lower plate 221. As shown in FIG. Driving of the first electric motor 23 is controlled by a controller.

A male screw is formed on the outer circumference of the ball screw rod 24 . An axial movement stage 25 is attached to the outer periphery of the ball screw rod 24 so as not to rotate about the axis. The axial movement stage 25 has a through hole through which the ball screw rod 24 penetrates, and the through hole is formed with a female screw that engages with a male screw formed on the outer periphery of the ball screw rod 24 . Therefore, when the ball screw rod 24 is rotated by driving the first electric motor 23, the axial movement stage 25 moves up and down along the axial direction of the ball screw rod 24, that is, the vertical direction.

The rotation unit 30 has a case 31 , a second electric motor 32 and a rotation stage 33 . The case 31 is formed in the shape of a rectangular parallelepiped with a space inside, and its upper wall is connected to the axial movement stage 25 of the axial movement unit 20 via an L-shaped bracket 34 . A second electric motor 32 is arranged inside the case 31 .

A disc-shaped rotary stage 33 is embedded in the lower wall of the case 31 . The rotating stage 33 is attached to the case 31 so as to be rotatable around the vertical axis via a bearing member such as a bearing. The rotary stage 33 is coaxially rotatably connected to the output shaft of the second electric motor 32 inside the case 31 . Therefore, when the second electric motor 32 is driven, the rotary stage 33 rotates around the vertical axis. Driving of the second electric motor 32 is controlled by a controller.

An inner inspection unit 40 is connected to the rotating unit 30 , and an outer inspection unit 50 is connected to the inner inspection unit 40 . FIG. 2 is a schematic cross-sectional view showing the connection configuration of the rotating unit 30, the inner inspection unit 40, and the outer inspection unit 50. As shown in FIG. As shown in FIG. 2 , the inner inspection unit 40 has an inner rod portion 41 , an inner inspection plate 42 , an inner Hall element 43 and an inner spacer 44 .

The inner rod portion 41 is a cylindrical member elongated in the vertical direction. The inner rod portion 41 has an enlarged diameter head portion 41a forming the upper end portion thereof, and a body portion 41b extending downward in FIG. 2 from the head portion 41a. An engagement member 35 is connected by a bolt to a portion of the lower surface of the rotation stage 33 of the rotation unit 30 near the outer periphery. The engaging member 35 includes a cylindrical body portion 35a extending downward from a portion near the outer periphery of the disk-shaped rotary stage 33, and a collar portion 35b extending radially inward from the lower end portion of the body portion 35a. have. The lower surface of the head portion 41 a of the inner rod portion 41 is engaged with the upper surface of the flange portion 35 b of the engaging member 35 . In this state, the engagement member 35 is tightened to the rotation stage 33 by bolts, so that the head portion 41 a of the inner rod portion 41 is sandwiched between the rotation stage 33 and the engagement member 35 . The inner rod portion 41 is fixed to the rotating unit 30 by such clamping. In this fixed state, the central axis of the rotary stage 33 and the longitudinal central axis of the main body portion 41b of the inner rod portion 41 are aligned. Therefore, when the rotary stage 33 rotates, the inner rod portion 41 rotates around the axis integrally therewith.

Further, as can be seen from FIG. 2, a part of the upper portion of the main body portion 41b of the inner rod portion 41 is formed with a connecting notch surface 41c that is notched radially inward. Further, an inner cutout surface 41d is formed in the lower portion of the main body portion 41b of the inner rod portion 41 by cutting it radially inward. The formation position of the connecting notch surface 41c and the formation position of the inner notch surface 41d in the circumferential direction of the main body portion 41b of the inner rod portion 41 substantially match.

An inner inspection plate 42 is arranged on the inner cutout surface 41d of the inner rod portion 41 so as to come into surface contact therewith. Then, the inner inspection plate 42 is fixed to the lower cutout surface 41d by bolts. The inner inspection plate 42 is arranged so as to protrude further downward from the lower end of the main body portion 41b of the inner rod portion 41 while being fixed to the inner cutout surface 41d. The inner inspection plate 42 has a mounting surface 42a facing radially outward of the body portion 41b of the inner rod portion 41 in a fixed state, and an inner spacer 44 made of an insulating material is attached to the mounting surface 42a. An inner Hall element 43 is attached through the hole. The inner Hall element 43 functions as a magnetic field sensor that detects the magnetic field created by the magnetic flux passing through it. As can be seen in FIG. 2, the inner spacer 44 and the inner Hall element 43 are attached to the lower portion of the inner test plate 42 .

The outer inspection unit 50 has an outer rod portion 51 , an outer inspection plate 52 , an outer Hall element 53 , an outer spacer 54 and an outer permanent magnet 55 .

Similarly to the inner rod portion 41, the outer rod portion 51 is also elongated in the vertical direction, and has a rectangular cross section when cut in the horizontal direction. The outer rod portion 51 has a head portion 51a constituting its upper end portion, and a body portion 51b extending downward in FIG. 2 from the head portion 51a. The head portion 51a is formed to protrude leftward in FIG. 2 from the main body portion 51b. Then, the outer rod portion 51 is attached to the inner rod portion 41 so that the left end surface of the head portion 51a comes into contact with the connection notch surface 41c formed in the upper portion of the main body portion 41b of the inner rod portion 41. are arranged. Then, the head portion 51a is fixed to the connecting notch surface 41c of the inner rod portion 41 via a fastening member such as a bolt. When the head portion 51a is fixed to the connecting notch surface 41c, the main body portion 51b of the outer rod portion 51 is arranged parallel to the main body portion 41b of the inner rod portion 41 with a certain gap therebetween. 3 is a cross-sectional view taken along the line III-III of FIG. 2, showing the state of connection between the body portion 41b of the inner rod portion 41 and the head portion 51a of the outer rod portion 51. As shown in FIG.

An outer cutout surface 51c is formed in a portion of the lower portion of the main body portion 51b of the outer rod portion 51 that faces the inner cutout surface 41d formed in the main body portion 41b of the inner rod portion 41 . The outer inspection plate 52 is arranged on the outer cutout surface 51c so as to come into surface contact therewith. Then, the outer inspection plate 52 is fixed to the outer cutout surface 51c by bolts. The outer inspection plate 52 is arranged so as to protrude further downward from the lower end of the main body portion 51b of the outer rod portion 51 while being fixed to the outer cutout surface 51c. Further, the outer inspection plate 52 has a mounting surface 52a that faces the mounting surface 42a of the inner inspection plate 42 attached to the inner rod portion 41 in a fixed state with a certain gap therebetween. , an outer Hall element 53 is attached via an outer spacer 54 made of an insulating material. The outer Hall element 53 functions as a magnetic field sensor that detects the magnetic field created by the magnetic flux passing through it. As can be seen in FIG. 2, the outer spacers 54 and the outer Hall elements 53 are attached to the lower portion of the outer test plate 52 .

Further, an outer permanent magnet 55 is embedded in a lower portion of the outer inspection plate 52 and at a position facing the outer Hall element 53 via the outer spacer 54 . In this embodiment, a neodymium magnet (NdFeB magnet) is used as the outer permanent magnet 55 . The outer permanent magnet 55 has two different magnetic poles (N pole and S pole), and is embedded in the outer inspection plate 52 so that the N pole faces the outer Hall element 53 with the outer spacer 54 interposed therebetween. .

As can be seen from FIG. 2, the inner inspection plate 42 and the outer inspection plate 52 are arranged so as to face each other. The inner Hall element 43 attached to the inner inspection plate 42 is arranged to face the outer Hall element 53 attached to the outer inspection plate 52 . Further, the body portion 41b of the inner rod portion 41 and the components attached thereto (the inner inspection plate 42, the inner Hall element 43, the inner spacer 44) are arranged in the inner peripheral space of the cylindrical superconductor to be inspected. It is sized so that it can be Further, when the body portion 41b of the inner rod portion 41 and the components attached thereto are arranged in the inner peripheral space of the cylindrical superconductor, the body portion 51b of the outer rod portion 51 and the components attached thereto These components (outer test plate 52, outer Hall element 53, outer spacer 54, outer permanent magnet 55) are dimensioned so that they are arranged on the outer peripheral side of the cylindrical superconductor. That is, when the main body portion 41b of the inner rod portion 41 and the components attached thereto are arranged in the inner peripheral space of the cylindrical superconductor, the main body portion 41b of the inner rod portion 41 and the main body portion 51b of the outer rod portion 51 The inner inspection unit 40 and the outer inspection unit 50 are configured so that the cylindrical peripheral surface of the cylindrical superconductor is sandwiched between the gaps.

2 and 3, a plurality of grooves 41e recessed radially inward are formed in the outer circumference of the body portion 41b of the inner rod portion 41 along the axial direction. In this embodiment, four grooves 41e are formed on the outer circumference of the body portion 41b of the inner rod portion 41 at regular intervals along the circumferential direction. A signal line having one end connected to the inner Hall element 43 is arranged in the groove 41e. 2, the signal line having one end connected to the outer Hall element 53 is connected to the surface of the body portion 51b of the outer rod portion 51 (specifically, the surface facing the body portion 41b of the inner rod portion 41). ). The other ends of these signal lines are electrically connected to a controller (not shown).

In the inspection apparatus 1 configured as described above, when the axially moving unit 20 (the first electric motor 23) is driven, the rotation unit 30, the inner inspection unit 40, and the outer inspection unit 50 move integrally in the vertical direction. That is, the inner Hall element 43 included in the inner inspection unit 40 and the outer Hall element 53 and the outer permanent magnet 55 included in the outer inspection unit 50 are connected so as to be integrally moved by driving the axial movement unit 20. It means that Further, when the rotation unit 30 (second electric motor 32) is driven, the inner inspection unit 40 and the outer inspection unit 50 are integrally rotated around the center axis of the body portion 41b of the inner rod portion 41. That is, the inner Hall element 43 provided in the inner inspection unit 40, and the outer Hall element 53 and the outer permanent magnet 55 provided in the outer inspection unit 50 are connected so as to integrally rotate by driving the rotation unit 30. It will be.

Next, a cylindrical superconductor to be inspected will be described. FIG. 4 is a schematic perspective view of a cylindrical superconductor 7. FIG. FIG. 5 is a schematic cross-sectional view of the cylindrical superconductor 7 cut along a plane including its central axis. As shown in FIGS. 4 and 5 , the cylindrical superconductor 7 has a cylindrical substrate 71 , an inner superconducting layer 72 and an outer superconducting layer 73 .

The cylindrical base material 71 is formed in a cylindrical shape, for example, from copper or the like. An inner superconducting layer 72 is formed on the outer peripheral surface of the cylindrical base material 71 . The inner superconducting layer 72 is formed in a cylindrical shape by spirally winding an elongated superconducting wire (superconducting tape) around the outer peripheral surface of the cylindrical substrate 71 . An outer superconducting layer 73 is formed on the outer periphery of an inner superconducting layer 72 formed in a cylindrical shape by spirally winding a superconducting wire. As with the inner superconducting layer 72 , the outer superconducting layer 73 is also formed in a cylindrical shape by spirally winding an elongated superconducting wire (superconducting tape) around the outer peripheral surface of the cylindrical inner superconducting layer 72 . That is, the cylindrical superconductor 7 is formed by laminating a cylindrical superconductor composed of two layers of superconducting wires on the outer circumference of the cylindrical base material 71 .

6A and 6B are views separately showing the spirally wound inner superconducting layer 72 and the outer superconducting layer 73. FIG. 6A shows the inner superconducting layer 72, and FIG. 6B shows the outer superconducting layer 73. showing. As can be seen from FIG. 6A, the inner superconducting layer 72 is formed in a cylindrical shape by spirally winding the superconducting wire, and the side edges of axially adjacent superconducting wires meet without gaps. Therefore, a boundary line (hereinafter referred to as a spiral boundary) B1 between adjacent side edges of the spirally wound superconducting wire is formed in a spiral shape. As can be seen from FIG. 6(b), the outer superconducting layer 73 is also formed in a cylindrical shape by spirally winding the superconducting wire, and the side edges of the axially adjacent superconducting wires are joined without any gap. For this reason, a boundary line (hereafter referred to as a spiral boundary) B2 between adjacent side edges of the spirally wound superconducting wire is formed in a spiral shape.

Further, as can be seen by comparing FIGS. 6(a) and 6(b), the formation position of the spiral boundary B1 formed in the inner superconducting layer 72 and the spiral boundary B2 formed in the outer superconducting layer 73 The formation positions are shifted in the axial direction, specifically, so that the spiral boundary B1 and the spiral boundary B2 are farthest apart in the axial direction. Both are formed so as to be out of pitch. Therefore, in the state where the outer superconducting layer 73 is laminated on the inner superconducting layer 72, the spiral boundary B1 in the inner superconducting layer 72 is positioned at the center position in the width direction of the superconducting wire constituting the outer superconducting layer 73. Thus, the spiral boundary B2 of the outer superconducting layer 73 is located at the central position in the width direction of the superconducting wire constituting the inner superconducting layer 72 .

The reason why the spiral boundary B1 of the inner superconducting layer 72 and the spiral boundary B2 of the outer superconducting layer 73 are shifted in the axial direction is as follows. This cylindrical superconductor 7 is used as the inner superconductor disclosed in Patent Document 1. In this case, the cylindrical superconductor 7 is configured so as to be able to form a superconducting current loop (shielding current) along its circumferential direction. Here, a superconducting current loop cannot be formed across the helical boundary B1 of the inner superconducting layer 72 and the helical boundary B2 of the outer superconducting layer 73 . Therefore, when the helical boundary B1 of the inner superconducting layer 72 and the helical boundary B2 of the outer superconducting layer 73 coincide with each other, a desired superconducting current loop is formed across these helical boundaries B1 and B2. I can't. Regarding this point, if the helical boundary B1 of the inner superconducting layer 72 and the helical boundary B2 of the outer superconducting layer 73 are axially displaced, the helical boundary B1 can be formed like the superconducting current loop L1 shown in FIG. A superconducting current loop that cannot be formed in the inner superconducting layer 72 because it straddles can be formed in the outer superconducting layer 73 without straddling the spiral boundary B2 as shown in FIG. 6(b). Similarly, a superconducting current loop that cannot be formed in the outer superconducting layer 73 because it straddles the spiral boundary B2 like the superconducting current loop L2 shown in FIG. It can be formed without straddling the spiral boundary B2. In this manner, the spiral boundary B1 of the inner superconducting layer 72 and the spiral boundary B2 of the outer superconducting layer 73 are shifted in the axial direction for the purpose of freely forming a superconducting current loop on the cylindrical peripheral surface of the cylindrical superconductor 7. ing. For details, refer to Patent Document 1.

In inspecting the cylindrical superconductor 7 with the inspection apparatus 1, the cylindrical superconductor 7 (specifically, the inner superconducting layer 72 and the outer superconducting layer 73) is brought into a superconducting state. In order to bring the cylindrical superconductor 7 into a superconducting state, it is necessary to cool the cylindrical superconductor 7 below the superconducting critical temperature Tc. For this purpose, in this embodiment, the cylindrical superconductor 7 is arranged in a container filled with liquid nitrogen.

FIG. 7 is a schematic cross-sectional view of a container 81 in which a cylindrical superconductor 7 is arranged. As shown in FIG. 7, the container 81 has a disk-shaped bottom wall 82 and a cylindrical side wall 83 standing upward from the peripheral edge of the bottom wall 82, and has a bottomed cylindrical shape with an open top surface. present. A support disc 84 is also mounted within the container 81 . Support disc 84 has an outer diameter equal to the inner diameter of side wall 83 and is fixed parallel to bottom wall 82 at a position slightly above bottom wall 82 . An annular groove 841 is formed in the center of the support disk 84, and an inner through hole 842 and an outer through hole 843 are formed inside and outside the annular groove 841, respectively. The inner and outer diameters of the annular groove 841 match the inner and outer diameters of the cylindrical superconductor 7 . The cylindrical superconductor 7 is placed in the container 81 with its lower end inserted into the annular groove 841 . Thereby, the cylindrical superconductor 7 is arranged coaxially with the container 81 within the container 81 .

Next, a method for inspecting the cylindrical superconductor 7 using the inspection apparatus 1 will be described. First, the inspection apparatus 1 is assembled as shown in FIG. Next, the manual handle 15 of the assembled inspection device 1 is rotated to move the joint block 21 to the uppermost position. As a result, the axial movement unit 20 connected to the manual lifting operation unit 10 moves to the uppermost position. Next, the first electric motor 23 of the axial movement unit 20 is controlled to move the axial movement stage 25 to the uppermost position. As a result, the rotation unit 30 connected to the axial movement unit 20 via the L-shaped bracket 34, the inner inspection unit 40 connected to the rotation unit 30, and the outer inspection unit 50 connected to the inner inspection unit 40 are Move together to the highest position.

Further, as shown in FIG. 7, one end (lower end) of the cylindrical superconductor 7 to be inspected is fixed in the annular groove 841 of the supporting disk 84 inside the container 81 . Next, the container 81 to which the cylindrical superconductor 7 is fixed is arranged directly below the inner inspection unit 40 and the outer inspection unit 50 of the inspection apparatus 1 . After that, the manual handle 15 of the manual elevation operation unit 10 is rotated to lower the inner inspection unit 40 and the outer inspection unit 50 . At this time, in a state in which the central axis of the main body portion 41b of the inner rod portion 41 of the inner inspection unit 40 coincides with the central axis of the cylindrical superconductor 7 in the container 81, the main body portion 41b and the components attached thereto ( The inner inspection plate 42, the inner Hall element 43, the inner spacer 44) enter the inner peripheral space of the cylindrical superconductor 7, and the body portion 51b of the outer rod portion 51 of the outer inspection unit 50 and the components attached thereto. Manually adjust the position of the container 81 with respect to the inspection device 1 so that (the outer inspection plate 52, the outer Hall element 53, the outer spacer 54, the outer permanent magnet 55) face the outer circumference of the cylindrical superconductor 7 in the container 81. do.

After the position adjustment is completed, the second electric motor 32 is controlled to fix the rotating unit 30 at a preset rotating position of 0°. Next, by controlling the first electric motor 23, the axial position of the axially moving unit 20 is adjusted so that the inner Hall element 43 and the outer Hall element 53 face the peripheral surface of the lowermost end of the cylindrical superconductor 7. set. After that, in order to prevent the magnetic field of the outer permanent magnet 55 from being captured by the cylindrical superconductor 7 , the first electric motor 23 is controlled so that the outer permanent magnet 55 is moved axially outward of the cylindrical superconductor 7 ( The inner inspection unit 40 and the outer inspection unit 50 are once moved upward so that the upper end is positioned above the upper end). Next, the container 81 is filled with liquid nitrogen, and the liquid nitrogen stops boiling. After the boiling of the liquid nitrogen stops, the first electric motor 23 is controlled again to lower the inner inspection unit 40 and the outer inspection unit 50 to the previously set axial positions. Then start the inspection. FIG. 8 is a diagram showing the positional relationship between the cylindrical superconductor 7 in the container 81 and the inspection apparatus 1 at the start of inspection. As shown in FIG. 8, the cylindrical superconductor 7 is completely submerged in the liquid nitrogen inside the container 81 . As a result, the cylindrical superconductor 7 is cooled below the superconducting critical temperature Tc, thereby making the cylindrical superconductor 7 (the inner superconducting layer 72 and the outer superconducting layer 73) superconducting. An inner inspection unit 40 is arranged on the inner peripheral side of the cylindrical superconductor 7 and an outer inspection unit 50 is arranged on the outer peripheral side of the cylindrical superconductor 7 . Therefore, the inner Hall element 43 of the inner inspection unit 40 is arranged on the inner peripheral side of the cylindrical superconductor 7, and the outer Hall element 53 and the outer permanent magnet 55 of the outer inspection unit 50 are arranged on the outer peripheral side of the cylindrical superconductor 7. be done.

FIG. 9 is a schematic diagram showing the arrangement relationship of the inner Hall element 43, the outer Hall element 53, and the outer permanent magnet 55 with respect to the cylindrical superconductor 7. As shown in FIG. As shown in FIGS. 8 and 9, the inner Hall element 43 is arranged to face the inner peripheral surface (cylindrical peripheral surface) of the cylindrical superconductor 7 . As described above, since the innermost circumference of the cylindrical superconductor 7 is formed by the cylindrical base material 71 , the inner Hall element 43 is formed through the cylindrical base material 71 . It will face layer 72 . The inner Hall element 43 according to this embodiment corresponds to the transmitted magnetic field detection sensor of the present invention.

The outer Hall element 53 is arranged to face the outer peripheral surface (cylindrical peripheral surface) of the cylindrical superconductor 7 , specifically, the outer superconducting layer 73 of the cylindrical superconductor 7 . The outer Hall element 53 according to this embodiment corresponds to the shielding magnetic field detection sensor of the present invention.

9, the outer permanent magnet 55 is arranged so that its N pole faces the outer peripheral surface (cylindrical peripheral surface) of the cylindrical superconductor 7 with the outer Hall element 53 interposed therebetween. The outer permanent magnet 55 is arranged at a position where the N pole side faces the inner Hall element 43 with the cylindrical peripheral surface of the cylindrical superconductor 7 interposed therebetween. The outer permanent magnet 55 according to this embodiment corresponds to the magnet of the present invention.

As shown in FIG. 9, the inner Hall element 43 has a magnetic sensing portion 43a (active area), and the outer Hall element 53 has a magnetic sensing portion 53a (active area). The inner Hall element 43 detects the magnetic field applied to its magnetic sensing portion 43a, and the outer Hall element 53 detects the magnetic field applied to its magnetic sensing portion 53a. The area of the portion where these magnetic sensing parts 43a and 53a face the cylindrical peripheral surface of the cylindrical superconductor 7, that is, the area of the active area, is larger than the area of the N pole surface of the outer permanent magnet facing the cylindrical superconductor 7. is also small.

In this inspection, first, the first electric motor 23 is controlled to move the axial movement unit 20 upward. When the axial movement unit 20 is moved upward, the rotation unit 30 connected to the axial movement unit 20, the inner inspection unit 40 connected to the rotation unit 30, and the outer inspection unit 50 connected to the inner inspection unit 40 are integrated. Typically, it moves upward from the position shown in FIG. As a result, the inner Hall element 43 of the inner inspection unit 40 moves (sweeps) upward along the inner peripheral surface of the cylindrical superconductor 7 while changing the facing position in the axial direction. move (sweep) upward along the outer peripheral surface of the cylindrical superconductor 7 while changing the facing position in the axial direction. At this time, the inner Hall element 43 moves upward while maintaining a constant radial distance from the inner peripheral surface of the cylindrical superconductor 7 , and the outer Hall element 53 moves upward from the outer peripheral surface of the cylindrical superconductor 7 . move upward while maintaining a constant radial distance between In addition, the outer permanent magnet 55 axially moves along the outer peripheral surface of the cylindrical superconductor 7 together with the inner Hall element 43 and the outer Hall element 53 while maintaining the relative positional relationship between the inner Hall element 43 and the outer Hall element 53 (sweeping step). ).

In addition, the inner Hall element 43 detects the magnitude of the magnetic field while moving along the inner peripheral surface of the cylindrical superconductor 7 in the axial direction, and the outer Hall element 53 detects the magnitude of the magnetic field along the outer peripheral surface of the cylindrical superconductor 7. The magnitude of the magnetic field is detected while moving in the axial direction.

FIG. 10 is a conceptual diagram showing the magnetic field detected by the outer Hall element 53. As shown in FIG. As shown in FIG. 10, the outer Hall element 53 is arranged to face the outer peripheral surface of the cylindrical superconductor 7 brought into a superconducting state. Also, the outer permanent magnet 55 is arranged at a position where its N pole faces the outer peripheral surface of the cylindrical superconductor 7 with the outer Hall element 53 interposed therebetween. The outer permanent magnet 55 therefore applies a magnetic field to the cylindrical superconductor 7 from its north pole. Since the cylindrical superconductor 7 is in a superconducting state here, a superconducting current (shielding current) is induced in the cylindrical superconductor 7 so as not to penetrate the applied magnetic field. This shielding current shields the applied magnetic field from entering the cylindrical superconductor. By shielding the applied magnetic field in this manner, a shielding magnetic field is formed between the cylindrical superconductor 7 and the outer permanent magnet 55 . Therefore, the outer Hall element 53 located between the cylindrical superconductor 7 and the outer permanent magnet 55 detects the magnitude of the shielding magnetic field.

FIG. 11 is a conceptual diagram showing the magnetic field detected by the inner Hall element 43. As shown in FIG. As shown in FIG. 11, the inner Hall element 43 is arranged to face the inner peripheral surface of the cylindrical superconductor 7 brought into a superconducting state. Further, the outer permanent magnet 55 is disposed at a position facing the inner Hall element 43 with its N pole facing the inner Hall element 43 with the cylindrical peripheral surface of the cylindrical superconductor 7 interposed therebetween. That is, the inner Hall element 43 and the outer permanent magnet 55 are arranged to face each other with the cylindrical superconductor 7 interposed therebetween. Here, as described above, the magnetic field applied to the cylindrical superconductor 7 from the N pole side of the outer permanent magnet 55 is shielded by the cylindrical superconductor 7. A part penetrates the cylindrical peripheral surface of the cylindrical superconductor 7 and reaches the inner peripheral side of the cylindrical superconductor 7 . In this way, a permeation magnetic field is formed on the inner peripheral side of the cylindrical superconductor 7 by the magnetic field transmitted through the cylindrical peripheral surface of the cylindrical superconductor 7 . Therefore, the inner Hall element 43 facing the inner peripheral surface of the cylindrical superconductor 7 detects the magnitude of the transmitted magnetic field.

Thus, the outer Hall element 53 detects the shielding magnetic field while moving along the axial direction of the cylindrical superconductor 7 by driving the axial movement unit 20 (shielding magnetic field detection step), and the inner Hall element 43 The transmission magnetic field is detected while moving along the axial direction of the cylindrical superconductor 7 by driving the axial movement unit 20 (transmission magnetic field detection step).

When the movement (sweeping) of the inner Hall element 43 and the outer Hall element 53 along the axial direction of the cylindrical superconductor 7 is completed when the rotation angle is 0°, the inner Hall element 43 and the outer Hall element 53 move to the cylindrical superconducting state. The uppermost end of the body 7 faces the cylindrical peripheral surface. Next, the second electric motor 32 is controlled to rotate the rotation unit 30 to a rotation position rotated by a predetermined angle, for example, 30° from the rotation angle of 0°. As a result, the inner Hall element 43 and the outer Hall element 53 rotate around the central axis of the cylindrical superconductor 7, and the position where the inner Hall element 43 faces the inner peripheral surface of the cylindrical superconductor 7 and the outer The position where the Hall element 53 faces the outer peripheral surface of the cylindrical superconductor 7 changes in the circumferential direction. Here, since the central axis of the inner inspection unit 40 and the central axis of the cylindrical superconductor 7 are aligned, the distance between the inner Hall element 43 before rotation and the inner peripheral surface of the cylindrical superconductor 7 is The distance between the inner Hall element 43 and the inner peripheral surface of the cylindrical superconductor 7 is equal, and the outer Hall element 53 and the outer peripheral surface of the cylindrical superconductor 7 before rotation and the outer Hall element 53 and the cylindrical superconductor 7 after rotation. The distance between the outer peripheral surface of the shaped superconductor 7 is equal. Next, the first electric motor 23 is controlled to move the axial movement unit 20 downward. When the axial movement unit 20 is moved downward, the rotation unit 30 connected to the axial movement unit 20, the inner inspection unit 40 connected to the rotation unit 30, and the outer inspection unit 50 connected to the inner inspection unit 40 are integrated. essentially move downwards. As a result, the inner Hall element 43 of the inner inspection unit 40 moves (sweeps) downward along the inner peripheral surface of the cylindrical superconductor 7 while changing the facing position in the axial direction. move (sweep) downward along the outer peripheral surface of the cylindrical superconductor 7 while changing the facing position in the axial direction. In addition, the outer permanent magnet 55 axially moves along the outer peripheral surface of the cylindrical superconductor 7 together with the outer Hall element 53 . At this time, the inner Hall element 43 detects the transmitted magnetic field while moving downward along the axial direction of the cylindrical superconductor 7, and the outer Hall element 53 moves downward along the axial direction of the cylindrical superconductor 7 to shield. Detect magnetic fields.

As described above, the movement and rotation of the inner Hall element 43 along the axial direction of the cylindrical superconductor 7 and the movement and rotation of the outer Hall element 53 and the outer permanent magnet 55 along the axial direction of the cylindrical superconductor 7 The rotation is repeated, and the inspection is finished when the inner Hall element 43 and the outer Hall element 53 have made one turn in the circumferential direction of the cylindrical superconductor 7 . Thereby, the transmission magnetic field and the shielding magnetic field over the entire cylindrical surface of the cylindrical superconductor 7 are detected. During the inspection, the body portion 41b of the inner rod portion 41 of the inner inspection unit 40 and the components connected thereto move up and down in the inner peripheral space of the cylindrical superconductor 7. Liquid nitrogen flows into and out of the inner peripheral space of the cylindrical superconductor 7 through an inner through-hole 842 and an outer through-hole 843 formed in the support disc 84 . Such inflow and outflow of liquid nitrogen suppresses pressure fluctuations in the inner peripheral space of the cylindrical superconductor 7 .

FIG. 12 is a diagram conceptually showing the relationship between the shielding magnetic field detected by the outer Hall element 53 and the presence or absence of defects in the cylindrical superconductor 7. As shown in FIG. As shown in FIG. 12( a ), the inspection region R is a hatched region of the cylindrical superconductor 7 facing the outer Hall element 53 . If no defect exists in the inspection area R, a required magnitude of shielding current is induced in the inspection area R in an attempt to shield the magnetic field applied from the north pole side of the outer permanent magnet 55 . Therefore, the shielding current shields the applied magnetic field from entering the cylindrical superconductor 7 . Therefore, the magnetic flux generated from the N pole of the outer permanent magnet 55 bends from the outer Hall element 53 located between the inspection area R and the outer permanent magnet 55, and passes through the magnetic sensing portion 53a of the outer Hall element 53. less magnetic flux. That is, when there is no defect in the inspection region R, the magnetic field is excluded from the space between the outer permanent magnet 55 and the cylindrical superconductor 7, so that the outer Hall element 53 located in the space therebetween detects the defect. The shielding magnetic field is weak.

On the other hand, as shown in FIG. 12(b), when a defect D exists in the inspection region R, a shielding current of a magnitude necessary for shielding the applied magnetic field is not induced in the inspection region R, and as a result, Part of the magnetic flux generated from the north pole side of the outer permanent magnet 55 travels through the defect D in the inspection region R because the applied magnetic field cannot be sufficiently eliminated. Since such magnetic flux passes through the magnetic sensing portion 53a of the outer Hall element 53 located between the inspection region R and the outer permanent magnet 55, the shielding magnetic field detected by the outer Hall element 53 is It is stronger than when it does not exist in the inspection area R. In other words, if there is a defect or the like in the region facing the outer Hall element 53 of the cylindrical peripheral surface of the cylindrical superconductor 7, the outer Hall element 53 detects the defect more than the case where the defect does not exist. The shielding magnetic field becomes stronger.

Thus, the magnitude of the shielding magnetic field detected by the outer Hall element 53 changes depending on the presence or absence of defects in the inspection region R. FIG. Specifically, when the defect D exists, the shielding magnetic field detected by the outer Hall element 53 becomes stronger. Therefore, by detecting the shielding magnetic field with the outer Hall element 53 while sweeping the outer Hall element 53 along the cylindrical peripheral surface of the cylindrical superconductor 7 (while the outer Hall element 53 moves), the presence or absence of defects, etc. It is possible to inspect the soundness of the superconducting state of the cylindrical superconductor 7 affected by

FIG. 13 is a diagram conceptually showing the relationship between the transmitted magnetic field detected by the inner Hall element 43 and the presence or absence of defects in the cylindrical superconductor 7. As shown in FIG. As shown in FIG. 13( a ), the hatched area of the cylindrical superconductor 7 facing the inner Hall element 43 is the inspection area R. As shown in FIG. If no defect exists in the inspection region R, a shielding current is induced in the inspection region R to shield the magnetic field applied from the north pole side of the outer permanent magnet 55 . Therefore, the magnetic flux generated from the N pole of the outer permanent magnet 55 is less likely to be detected by the inner Hall element 43 located on the opposite side of the inspection region R from the outer permanent magnet 55 . As described above, when the magnetic field applied from the outer permanent magnet 55 is increased, part of the magnetic flux passes through the inspection region R. The penetrating magnetic field is weak. That is, when there is no defect in the inspection area R, the transmitted magnetic field detected by the inner Hall element 43 is weak.

On the other hand, as shown in FIG. 13(b), when a defect D exists in the inspection region R, part of the magnetic flux generated from the N pole side of the outer permanent magnet 55 passes through the defect D and the inner Hall element 43 is likely to pass through the magnetic sensing portion 43a. Therefore, when a defect or the like exists in the inspection region R, the transmitted magnetic field detected by the inner Hall element 43 is stronger than when there is no defect.

Thus, the magnitude of the transmitted magnetic field detected by the inner Hall element 43 changes depending on the presence or absence of defects in the inspection region R. FIG. Specifically, when the defect D exists, the transmitted magnetic field detected by the inner Hall element 43 becomes stronger. Therefore, by detecting the transmitted magnetic field with the inner Hall element 43 while sweeping the inner Hall element 43 along the cylindrical peripheral surface of the cylindrical superconductor 7 (while the inner Hall element 43 moves), the presence or absence of defects etc. It is possible to check the integrity of the cylindrical superconductor 7 affected by

In addition, in this embodiment, since the applied magnetic field is generated using the permanent magnet (the outer permanent magnet 55), there is no need for auxiliary equipment such as a power supply for generating the applied magnetic field. Therefore, the structure of the inspection device 1 can be simplified.

<Confirmation experiment of defect detection>
Whether defects intentionally formed in the inner superconducting layer 72 and the outer superconducting layer 73 of the cylindrical superconductor 7 can be detected using the inspection apparatus 1 according to the present embodiment, that is, the cylindrical superconductor A confirmation experiment was conducted to see if the soundness of the superconducting state of No. 7 could be inspected. FIG. 14A shows a cylindrical superconductor 7 with an inner superconducting layer 72 and an outer superconducting layer 73 that are intentionally defective. 14A(a) is a top view of the cylindrical superconductor 7, FIG. 14A(b) is a view in the direction of arrow A in FIG. 14A(a), and FIG. It is a B direction arrow directional view. 14A(b) and 14A(c) are side views of the cylindrical superconductor 7 viewed from opposite directions. In these figures, the spiral boundary B1 of the inner superconducting layer 72 is indicated by a dashed line. , the spiral boundary B2 of the outer superconducting layer 73 is indicated by a solid line. In the following description, the defects formed in the outer superconducting layer 73 will be explained using FIG. 14A(c), and the defects formed in the inner superconducting layer 72 will be explained using FIG. 14A(b).

As shown in FIG. 14A(c), the outer superconducting layer 73 has a superconducting wire SCout whose both ends are represented by solid lines, viewed from above from the winding start position S2 on the upper end side (see FIG. 14A(a)). It is formed into a cylindrical shape by helically winding about 12 downward turns in a counterclockwise direction (as viewed from the direction shown). Defect Dout is formed at the end of the fourth turn and the end of the eighth turn from the top. Here, when the circumferential position of the outer superconducting layer 73 is represented by a rotation angle that changes from 0° to 360° by spiral winding for one turn with the rotation angle S2 at the winding start position S2 being 0°, the outer superconducting layer 73 The position of the defect Dout formed in the layer 73 is the end of the 4th turn from the top with a rotation angle of 0° and the end of the 8th turn from the top with a rotation angle of 0°.

In addition, as shown in FIG. 14A(b), the inner superconducting layer 72 is arranged such that the superconducting wire SCin, whose both ends are indicated by dashed lines, is viewed from above from the winding start position S1 on the upper end side (FIG. 14A(a) )) is formed into a cylindrical shape by spirally winding downward for about 12 turns counterclockwise. Defects Din are formed at the end positions of the fourth turn and the end position of the eighth turn from the top. Here, as shown in FIG. 14A(a), the winding start position S1 of the inner superconducting layer 72 is shifted from the winding start position S2 of the outer superconducting layer 73 by 180°. Therefore, when the rotation angle of the outer superconducting layer 73 is used as a reference (that is, the rotation angle of the position S1 is 0°), the position of the defect Din formed in the inner superconducting layer 72 is at the end of the fourth turn from the top. There is a position where the rotation angle is 180°, and a position where the rotation angle is 180° at the end of the 8th turn from the top. 14A shows the axial position (z-direction position) of each superconducting layer shown in FIGS. 14A(b) and 14A(c). The position of the axial position z≈8 mm is the upper end position of each superconducting layer, and the position of the axial position z≈147 mm is the lower end position of each superconducting layer.

FIG. 14B is a diagram showing a state in which the superconducting wire SCin forming the inner superconducting layer 72 and the superconducting wire SCout forming the outer superconducting layer 73 are developed. As shown in FIG. 14B, in the inner superconducting layer 72, defects Din are present at the end position of the fourth round (fourth turn) from the winding start position S1 and the end position of the eighth round (eighth turn). formed. Further, in the outer superconducting layer 73, defects Dout are formed at the end position of the fourth round (fourth turn) from the winding start position S2 and the end position of the eighth round (eighth turn).

FIG. 15 is a development view of a cylindrical body in which the inner superconducting layer 72 and the outer superconducting layer 73 are overlapped. In FIG. 15, the helical boundary B1 of the inner superconducting layer 72 is indicated by a dashed line, and the helical boundary B2 of the outer superconducting layer 73 is indicated by a solid line. The defects Din formed in the inner superconducting layer 72 are located between the pair of spiral boundaries B1 forming the end of the fourth turn from the top and between the pair of spiral boundaries B1 forming the end of the eighth turn from the top. formed in between. The defect Dout formed in the outer superconducting layer 73 is located between the pair of spiral boundaries B2 forming the end of the fourth turn from the upper side and between the pair of spiral boundaries B2 forming the end of the eighth turn from the upper side. formed in between. Further, as can be seen from FIG. 15, the spiral boundary B1 of the inner superconducting layer 72 is shifted from the spiral boundary B2 of the outer superconducting layer 73 by 1/2 pitch in the axial direction. Therefore, the defect Din formed in the inner superconducting layer 72 is formed on the spiral boundary B2 of the outer superconducting layer 73, and the defect Dout formed in the outer superconducting layer 73 is formed on the spiral boundary B2 of the inner superconducting layer 72. It will be formed on B1.

A Gd—Ba—Cu—O-based superconducting material was used as the superconducting wires forming the inner superconducting layer 72 and the outer superconducting layer 73 . The superconducting wire has a width of 12 mm and a thickness of 0.12 mm. Further, each defect Din, Dout is formed by bending the superconducting wire in a U shape so as to have a radius smaller than the allowable bending radius on the front side and the back side of the superconducting wire.

The cylindrical superconductor 7 having the inner superconducting layer 72 and the outer superconducting layer 73 having the above configuration was inspected using the inspection apparatus 1 . Here, outer permanent magnet 55 has a columnar shape of φ5 mm×height 15 mm, and is arranged so that the N pole surface formed on one end surface faces outer superconducting layer 73 . The size of the outer permanent magnet 55, specifically, the diameter (5 mm) of the north pole surface of the outer permanent magnet 55 is smaller than the width (12 mm) of the superconducting wire. The radial distance between the outer permanent magnet 55 and the outer superconducting layer 73 is 6 mm, the radial distance between the outer Hall element 53 and the outer superconducting layer 73 is 3 mm, and the inner Hall element 43 and the inner superconducting layer 72 are separated. The inner inspection unit 40 and the outer inspection unit 50 of the inspection apparatus 1 were arranged with respect to the cylindrical superconductor 7 so that the radial distance between them was 3 mm.

Then, after the cylindrical superconductor 7 is immersed in liquid nitrogen to bring the cylindrical superconductor 7 into a superconducting state, the inner inspection unit 40 and the outer inspection unit 50 are moved in the axial direction, and the inner Hall element 43 and The outer Hall element 53 was axially swept along the cylindrical surface of the cylindrical superconductor. Further, the rotation angle of the rotary stage 33 is rotated by 30°, and each Hall element is swept in the above-described axial direction at each rotation angle. The outer Hall element 53 detected the shielding magnetic field in each inspection area.

16 shows the measurement results of the shielding magnetic field detected by the outer Hall element 53, and FIG. 17 shows the measurement results of the transmitted magnetic field detected by the inner Hall element 43. FIG. In FIGS. 16 and 17, the vertical axis is the strength of the magnetic field (arbitrary unit), and the horizontal axis is the axial position of the inspection region. Here, the axial position near z=8 mm represents the upper end position of each cylindrical superconducting layer, and the axial position near z=147 mm represents the lower end position of each cylindrical superconducting layer. 16 and 17 each show 12 measurement graphs, and these graphs show the Hall elements 43 and 53 in the axial direction with the rotary stage 33 fixed at a predetermined rotation angle. Represents the change in magnetic field strength detected when swept. Among the 12 measurement graphs, the uppermost graph represents changes in the magnetic field intensity when the rotation angle of the rotary stage 30 is 360°, and thereafter, the rotation angle increases by 30° from 360° as it goes downward. Represents the change in magnetic field strength as it decreases. Here, when the rotation angle of the rotary stage 30 is 0° (=360°), the inner Hall element 43 and the outer Hall element 53 are positioned at the winding start position S2 of the upper end of the superconducting wire constituting the outer superconducting layer 73. The rotational position of the rotary stage 30 is adjusted so that they face each other. Here, when the circumferential position of the outer superconducting layer 73 is represented by a rotation angle, the rotation angle of the position S2 is 0°. That is, the rotation angle of the rotating stage 30 and the rotation angle representing the circumferential position of the outer superconducting layer 73 match. Accordingly, the rotation angle for each graph shown in FIGS. 16 and 17 represents the rotation angle of the outer superconducting layer 73. FIG.

16 and 17, the spiral boundary B1 of the inner superconducting layer 72 is indicated by a dashed line, and the spiral boundary B2 of the outer superconducting layer 73 is indicated by a solid line. As can be seen from FIG. 16, at the fourth and eighth turns from the upper end positions (z≈8 mm) of the superconducting layers 72 and 73, the shielding magnetic fields near the rotation angles of 360° and 180° become stronger. there is Similarly, as can be seen from FIG. 17, at the 4th and 8th turns from the upper end position (z≈8 mm) of each of the superconducting layers 72 and 73, the transmission magnetic field near the rotation angle of 360° and the rotation angle of 180° getting stronger. These positions where the shielding magnetic field and the penetrating magnetic field are strong correspond to the positions of intentionally formed defects in the inner superconducting layer 72 and the outer superconducting layer 73 . Therefore, by detecting the shielding magnetic field and/or the penetrating magnetic field with the inspection apparatus 1 according to the present embodiment, the presence or absence of defects in the cylindrical superconductor 7, that is, the soundness of the superconducting state of the cylindrical superconductor 7 can be inspected. proved to be possible.

FIG. 18 is a diagram showing the measurement results of the shielding magnetic field shown in FIG. 16 mapped onto a developed view of the cylindrical superconductor 7, and FIG. 19 shows the measurement results of the transmission magnetic field shown in FIG. 1 is a diagram showing mapping on a developed view of . By mapping the strength of the magnetic field on the developed view of the cylindrical superconductor 7 as shown in these figures, the presence of defects can be clearly grasped.

Further, in FIG. 18, the line thinly represented in the oblique horizontal direction is the spiral boundary B2 of the outer superconducting layer 73, and in FIG. This is the spiral boundary B1. In particular, as can be seen from FIG. 18, defects Dout of the outer superconducting layer 73 represented at rotation angles of 0° and 360° are formed between a pair of vertically adjacent spiral boundaries B2, and are formed at rotation angles of about 180°. is formed on the spiral boundary B2. As described above, the helical boundary B1 of the inner superconducting layer 72 is formed so as to be axially shifted from the helical boundary B2 of the outer superconducting layer 73 by a half pitch, so the defect Din of the inner superconducting layer 72 is , are positioned on the spiral boundary B2 of the outer superconducting layer 73 when viewed from the outside.

That is, if a defect is found between the adjacent spiral boundaries B2 of the outer superconducting layer 73, it is understood that the defect is formed within the outer superconducting layer 73. FIG. Also, if a defect is found on the spiral boundary B2 of the outer superconducting layer 73, it is found that the defect is formed within the inner superconducting layer 72. FIG. As described above, according to the present embodiment, it is possible to determine in which layer of the cylindrical superconductor formed in a plurality of layers by spirally winding the superconducting wire the defect exists in, from the relationship between the defect position and the spiral boundary. , can be determined.

FIG. 20 shows the rotation angle and the strength of the magnetic field when the position of the cylindrical peripheral surface of the cylindrical superconductor 7 (the inner superconducting layer 72 and the outer superconducting layer 73) formed by spirally winding the superconducting wire is represented by the rotation angle. It is a graph showing the relationship with (size). In FIG. 20, the vertical axis is the strength of the magnetic field, and the horizontal axis is the rotation angle θ representing the position of the cylindrical peripheral surface. Regarding the rotation angle θ, the winding start position S2 of the outer superconducting layer 73 is -360°, the first turn portion is expressed as a rotation angle of -360° to 0°, and the second turn portion is expressed as a rotation angle of 0° to 0°. It is expressed as 360°, and is expressed so that the rotation angle increases continuously for subsequent turns. In this case, the rotation angle θ of the winding start position S1 of the inner superconducting layer 72 is −180°. Two graphs A and B are shown in FIG. 20, and both graphs were created based on the mapping results shown in FIG. Here, graph A shows the strength of the magnetic field on a line tracing the central position in the width direction of two adjacent spiral boundaries B2 shown in FIG. It was created by plotting corresponding to the rotation angle θ as . From this graph A, the presence or absence of defects in the outer superconducting layer 73 is determined. Graph B shows the strength of the magnetic field on a line along the spiral direction along the position on the spiral boundary B2 shown in FIG. Created by plotting. Based on this graph B, the presence or absence of defects in the inner superconducting layer 72 is determined.

As can be seen from FIG. 20, in graph A, the magnetic field is strong at the position where the rotation angle θ is 1080° and the position where the rotation angle θ is 2520°. The rotational positions of the defect Dout intentionally formed in the outer superconducting layer 73 are the positions of 1080° and 2520° from the position A0 according to FIG. Further, in graph B, the magnetic field is strong at the positions where the rotation angle θ is 1260° and 2700° (the position advanced by 180° from the rotation position of the defect Dout). The rotational positions of the defect Din intentionally formed in the inner superconducting layer 72 are 1260° and 2700° from the position B0 according to FIG. In this manner, the presence or absence of defects in the cylindrical superconductor 7 can be inspected by using the inspection apparatus 1 according to this embodiment.

(Modification 1)
In the first embodiment described above, the axial movement unit 20 is driven at a predetermined rotation position where the rotation angle of the rotation unit 30 is fixed. As a result, the outer Hall element 53 and the inner Hall element 43 detect the shielding magnetic field and the penetrating magnetic field while moving (sweeping) in the axial direction. Then, after the movement (sweeping) in the axial direction is completed, the rotation angle is changed, and at the changed rotation position, the outer Hall element 53 and the inner Hall element 43 are moved in the axial direction again (while being swept). Detect the shielding magnetic field and the penetrating magnetic field. That is, the shielding magnetic field and the penetrating magnetic field are detected while sweeping the outer Hall element 53 and the inner Hall element 43 in the axial direction at a plurality of rotational positions. However, while the axial position is fixed, the outer Hall element 53 and the inner Hall element 43 are rotated by driving the rotating unit 30, and the shielding magnetic field and the transmission are detected while the outer Hall element 53 and the inner Hall element 43 are rotated. A magnetic field may be detected. Then, after the rotational movement is completed, the axial position is changed, and at the changed axial position, the outer Hall element 53 and the inner Hall element 43 again detect the shielding magnetic field and the penetrating magnetic field while rotating (sweeping). may That is, the shielding magnetic field and the penetrating magnetic field may be detected while the outer Hall element 53 and the inner Hall element 43 are rotating (swept) at a plurality of axial positions.

(Modification 2)
In the above-described first embodiment, an example in which the inner Hall element 43 detects the penetrating magnetic field and the outer Hall element 53 detects the shielding magnetic field is shown. However, the shielding magnetic field can be detected by the inner Hall element 43 and the transmitted magnetic field can be detected by the outer Hall element 53 . In this case, an inner permanent magnet arranged on the inner peripheral side of the superconducting cylindrical body 7 is used instead of the outer permanent magnet 55 shown in the first embodiment. FIG. 21 is a schematic cross-sectional view showing the connection configuration of the rotation unit 30, the inner inspection unit 40, and the outer inspection unit 50 of the inspection apparatus 1 according to Modification 2. As shown in FIG. As shown in FIG. 21, the inner permanent magnet 45 is embedded in the lower portion of the inner inspection plate 42 of the inner inspection unit 40 at a position facing the inner Hall element 43 via the inner spacer 44 . The inner permanent magnet 45 has two different magnetic poles (N pole and S pole), and is embedded in the inner inspection plate 42 so that the N pole faces the inner Hall element 43 with the inner spacer 44 interposed therebetween. A neodymium magnet (NdFeB magnet) can be used as the inner permanent magnet 45 . Also, the outer permanent magnet 45 is omitted. Of the configuration of the inspection apparatus according to this example, the configuration of portions other than the above is the same as the configuration of the inspection apparatus according to the first embodiment.

FIG. 22 is a diagram showing the arrangement relationship between the inspection device 1 and the cylindrical superconductor 7 when the cylindrical superconductor 7 set in the container 81 is inspected using the inspection device 1 according to this example. . As shown in FIG. 22, the inner inspection unit 40 of the cylindrical superconductor 7 is arranged in the inner peripheral space of the cylindrical superconductor 7 . Therefore, the inner permanent magnet 45 and the inner Hall element 43 provided in the inner inspection unit 40 are also arranged in the inner circumferential space of the cylindrical superconductor 7 . The inner Hall element 43 is arranged to face the inner peripheral surface of the cylindrical superconductor 7 . The inner permanent magnet 45 is arranged so that the N pole side faces the inner peripheral surface of the cylindrical superconductor 7 with the inner Hall element 43 interposed therebetween. Further, the outer Hall element 53 is arranged on the outer peripheral side of the cylindrical superconductor 7 and arranged to face the outer peripheral surface of the cylindrical superconductor 7 . Here, the inner permanent magnet 45 is attached to the outer Hall element 53 so that the N pole faces the outer Hall element 53 across the cylindrical surface of the cylindrical superconductor 7 . is placed facing the

According to the inspection apparatus 1 according to Modification 2, the magnetic field applied from the inner peripheral side of the cylindrical superconductor 7 from the N pole of the inner permanent magnet 45 is shielded by the cylindrical peripheral surface of the cylindrical superconductor 7. As a result, a shielding magnetic field is formed on the inner peripheral side of the cylindrical superconductor 7 . The shielding magnetic field thus formed is detected by an inner Hall element 43 arranged facing the inner peripheral surface of the cylindrical superconductor 7 . The inner Hall element 43 detects the shielding magnetic field while moving along the cylindrical peripheral surface (inner peripheral surface) of the cylindrical superconductor 7 by driving the axially moving unit 20 and the rotating unit 30 . That is, the inner Hall element 43 is used as a shielding magnetic field detection sensor.

In addition, the magnetic field applied from the N pole of the inner permanent magnet 45 to the cylindrical superconductor 7 from the inner peripheral side thereof penetrates the cylindrical peripheral surface of the cylindrical superconductor 7, so that the outer peripheral side of the cylindrical superconductor 7 A penetrating magnetic field is formed. The transmitted magnetic field thus formed is detected by an outer Hall element 53 arranged facing the outer peripheral surface of the cylindrical superconductor 7 . The outer Hall element 53 detects the transmitted magnetic field while moving along the cylindrical peripheral surface (outer peripheral surface) of the cylindrical superconductor 7 by driving the axially moving unit 20 and the rotating unit 30 . That is, the outer Hall element 53 is used as a transmitted magnetic field detection sensor.

(Second embodiment)
In the above-described first embodiment, an example in which the axial movement unit 20 and the rotation unit 30 are separately driven has been described. Specifically, an example in which the axial movement unit 20 is driven while the rotation unit 30 is stopped has been described. In this embodiment, an example in which the axial movement unit 20 and the rotation unit 30 are driven at the same time will be described.

In this embodiment, the controller interlocks and controls the driving of both units 30 and 20 so that the rotation unit 30 is rotationally driven in one direction and the axial movement unit 20 is axially moved in one direction. When the two units 30 and 20 are thus interlocked and controlled, the inner inspection unit 40 and the outer inspection unit 50 move spirally. Therefore, the inner Hall element 43 attached to the inner inspection unit 40 and the outer Hall element 53 and the outer permanent magnet 55 attached to the outer inspection unit 50 also move spirally. By spirally moving the inner Hall element 43 and the outer Hall element 53 along the cylindrical peripheral surface of the cylindrical superconductor 7 in this manner, the entire cylindrical peripheral surface of the cylindrical superconductor 7 can be efficiently heated. The integrity of the superconducting state can be inspected.

In particular, when the cylindrical superconductor 7 to be inspected comprises an inner superconducting layer 72 and an outer superconducting layer 73 formed cylindrically by spirally winding a superconducting wire, as shown in the first embodiment. , the rotation unit 30 and the axial movement unit 20 are preferably controlled such that the inner Hall element 43 and the outer Hall element 53 move along the direction of the spiral winding. According to this, the inspection can be performed along the longitudinal direction of the superconducting wire.

When the cylindrical superconductor 7 has the inner superconducting layer 72 and the outer superconducting layer 73 described above, the inner Hall element 43 and/or the outer Hall element 53 may each be composed of two Hall elements.

FIG. 23 is a schematic diagram showing an example of spirally sweeping an outer Hall element 531 having two Hall elements. As shown in FIG. 23, the outer Hall element 531 has a first outer Hall element 532 and a second outer Hall element 533 . These Hall elements 532 and 533 are configured to be integrally movable.

FIG. 24 is a diagram showing the positional relationship between the outer Hall element 531 and the inner superconducting layer 72 and the outer superconducting layer 73 of the cylindrical superconductor 7. As shown in FIG. As shown in FIG. 24 , the first outer Hall element 532 faces the spiral boundary B1 of the inner superconducting layer 72 and the second outer Hall element 533 faces the spiral boundary B2 of the outer superconducting layer 73 . Here, the spiral boundary B1 is located at the center in the width direction of the superconducting wire constituting the outer superconducting layer 73, and the spiral boundary B2 is located at the center in the width direction of the superconducting wire constituting the inner superconducting layer 72. . Therefore, the first outer Hall element 532 faces the central position of the superconducting wire constituting the outer superconducting layer 73 in the width direction, and the second outer Hall element 533 faces the superconducting wire constituting the inner superconducting layer 72 in the width direction. It will face the central position. In addition, the outer permanent magnet 55 is arranged to face the outer peripheral surface of the cylindrical superconductor 7 with the outer Hall element 531 interposed therebetween, and the north pole of the outer permanent magnet 55 is arranged to face the outer peripheral surface of the cylindrical superconductor 7 with the outer Hall element 531 interposed therebetween. facing the

The outer Hall element 531 configured as described above is spirally swept along the spiral boundaries B1 and B2. At this time, a shielding magnetic field formed by shielding the magnetic field applied from the N pole of the outer permanent magnet 55 to the cylindrical superconductor 7 by the outer superconducting layer 73 is mainly detected by the first outer Hall element 532. be. In addition, the shielding magnetic field formed by shielding the magnetic field applied from the N pole of the outer permanent magnet 55 to the cylindrical superconductor 7 by the inner superconducting layer 72 is mainly detected by the second outer Hall element 533. .

Therefore, by continuously plotting the magnetic field strength detected by the spirally moving first outer Hall element 532, graph A of FIG. By continuously plotting the magnetic field strength detected by element 533, graph B of FIG. 20 is produced in real time. By creating the graph shown in FIG. 20 in real time in this way, inspection results can be obtained without performing the mapping work and the like shown in the first embodiment, and the inspection procedure can be simplified. .

(Third embodiment)
Next, a third embodiment of the invention will be described. In the above-described first embodiment, the cylindrical superconductor 7 is immersed in liquid nitrogen to cool the cylindrical superconductor 7 into a superconducting state. An example of checking sanity was given. In the present embodiment, an example will be described in which the inspection apparatus 1 is used to inspect the soundness of the superconducting state of the cylindrical superconductor in a superconducting state by cooling the cylindrical superconductor using a refrigerator.

FIG. 25 is a diagram showing a state in which the inspection apparatus 1 inspects the cylindrical superconductor 7A cooled by the refrigerator. As shown in FIG. 25, an inner inspection unit 40 is arranged on the inner peripheral side of the cylindrical superconductor 7A cooled by the refrigerator 6, and an outer inspection unit 50 is arranged on the outer peripheral side of the cylindrical superconductor 7A. be. By driving the inspection device 1 in this state, the cylindrical superconductor 7A is inspected.

FIG. 26 shows the refrigerator 6, the cylindrical superconductor 7A cooled by the refrigerator 6, the inner Hall element 43 attached to the inner inspection unit 40 of the inspection apparatus 1, and the outer Hall element 43 attached to the outer inspection unit 50. 5 is a schematic diagram showing the arrangement relationship between a Hall element 53 and an outer permanent magnet 55; FIG. As shown in FIG. 26 , the refrigerator 6 has a refrigerator main body 61 , an extension portion 62 and a cold stage 63 . Freezing is generated inside the refrigerator main body 61 . The generated refrigeration is transmitted to cold stage 63 via extension 62 . Therefore, by driving the refrigerator 6, the cold stage 63 is cooled to a predetermined temperature, for example, a temperature equal to or lower than the superconducting critical temperature Tc of the cylindrical superconductor 7A.

The cold stage 63 is formed in a disc shape, and is connected to the tip (upper end) of the extended portion 62 so that one end surface (upper surface) faces upward. A cylindrical superconductor 7 A is coaxially arranged on the cold stage 63 . In this embodiment, the cylindrical superconductor 7A is composed of a cylindrical substrate 71A and a sheet-like superconductor 74. As shown in FIG. The cylindrical base member 71A has a cylindrical portion and a flange radially extending from one end (lower end in FIG. 26) of the cylindrical portion. Therefore, the cylindrical portion of the cylindrical substrate extends upward from the cold stage 63 . Also, most of the outer peripheral surface of the cylindrical portion of the cylindrical substrate 71A is formed with a concave portion to which the superconductor 74 can be attached. A sheet-like superconductor 74 is attached to this concave portion. Thereby, the superconductor 74 is formed in a cylindrical shape.

A vacuum insulation container 64 is arranged on the upper part of the refrigerator main body 61 . The vacuum insulation container 64 has a first container portion 641 , a disk-shaped member 642 and a second container portion 643 . The first container part 641 has a cylindrical shape, and its lower end surface is airtightly fixed to the upper surface of the refrigerator main body 61 . A first container portion 641 is arranged so as to stand upward from the upper surface of the refrigerator main body 61 and cover the extended portion 62 of the refrigerator 6 and the cold stage 63 from the outer peripheral side thereof.

A disk-shaped member 642 is arranged at the upper end of the first container portion 641 . The disk-shaped member 642 is arranged coaxially with the cold stage 63 at a position slightly above the cold stage 63 , and its lower surface is airtightly fixed to the upper end of the first container part 641 . A circular hole 642 a having a diameter slightly larger than the diameter of the cylindrical superconductor 7 is formed in the central portion of the disk-shaped member 642 . The cylindrical superconductor 7A on the cold stage 63 penetrates the circular hole 642a of the disk-shaped member 642 and extends upward.

The second container portion 643 has an outer cylindrical portion 643a, an inner cylindrical portion 643b, an inner bottom portion 643c, and a ring-shaped upper wall portion 643d. A lower end portion of the outer peripheral surface of the outer cylindrical portion 643 a is airtightly fixed to the inner peripheral surface of the circular hole 642 a of the disk-shaped member 642 . The outer cylindrical portion 643a extends upward from the inner peripheral wall of the circular hole 642a so as to cover the superconductor 74 attached to the cylindrical portion of the cylindrical base material 71A of the cylindrical superconductor 7A from the outer peripheral side. . Therefore, the outer cylindrical portion 643a is arranged along the outer peripheral surface of the cylindrical superconductor 7A.

The outer peripheral edge of the ring-shaped upper wall portion 643d is connected to the upper end of the outer cylindrical portion 643a. The ring-shaped upper wall portion 643d is arranged in a ring shape so as to cover the upper end of the cylindrical superconductor 7A. The upper end of the inner cylindrical portion 643b is connected to the inner peripheral edge of the ring-shaped upper wall portion 643d. The inner peripheral cylindrical portion 643b extends in the axial direction of the cylindrical superconductor 7A from the inner peripheral edge of the ring-shaped upper wall portion 643d so as to face the inner peripheral surface of the cylindrical portion of the cylindrical substrate 71A of the cylindrical superconductor 7A. extending downward along the Therefore, the inner cylindrical portion 643b is arranged along the inner peripheral surface of the cylindrical superconductor 7A on the inner peripheral side thereof. An inner peripheral bottom portion 643c is connected to the lower end of the inner peripheral cylindrical portion 643b. As shown in FIG. 26, the inner peripheral bottom portion 643c is located slightly above the cold stage 63 and slightly below the lower end position of the superconductor 74 of the cylindrical superconductor 7A.

By disposing the vacuum insulation container 64 as described above, an insulation space surrounded by the upper surface portion of the refrigerator main body 61, the first container portion 641, the disk-shaped member 642, and the second container portion 643 is formed. be done. The extended portion 62 of the refrigerator 6 and the cold stage 63 are arranged in the space surrounded by the first container portion 641 and the disk-shaped member 642 in the heat insulating space. A cylindrical superconductor 7A is disposed in a space sandwiched between the outer cylindrical portion 643a and the inner cylindrical portion 643b of the second container portion 643 in the heat insulating space.

When the refrigerator 6 configured as described above is driven, the cold stage 63 is cooled, and further the cylindrical superconductor 7A placed on the cold stage 63 is cooled. Thereby, the cylindrical superconductor 7A is cooled to the superconducting critical temperature Tc or less, and the cylindrical superconductor 7A is brought into a superconducting state.

Further, as shown in FIG. 26, the inner Hall element 43 of the inner inspection unit 40 provided in the inspection apparatus 1 is placed on the inner peripheral surface of the cylindrical superconductor 7A with the inner peripheral cylindrical portion 643b of the second container portion 643 interposed therebetween. The outer Hall element 53 of the outer inspection unit 50 included in the inspection apparatus 1 is arranged to face the outer peripheral surface of the cylindrical superconductor 7A with the outer cylindrical portion 643a of the second container portion 643 interposed therebetween. In this state, by sweeping the inner Hall element 43 and the outer Hall element 53 along the cylindrical peripheral surface (inner peripheral surface and outer peripheral surface) of the cylindrical superconductor 7A, the inner Hall element 43 detects the transmitted magnetic field. , and the shielding magnetic field is detected by the outer Hall element 53 . In this way, the soundness of the superconducting state of the cylindrical superconductor 7A is inspected. Thus, according to this embodiment, a cylindrical superconductor cooled by a refrigerator can be inspected.

(Fourth embodiment)
FIG. 27 is a diagram showing a state in which the cylindrical superconductor 7A incorporated in the superconducting magnet of the NMR apparatus is inspected by the inspection apparatus 1A. FIG. 28 shows a superconducting magnet 100 incorporating a cylindrical superconductor 7A. First, the configuration of the superconducting magnet 100 will be described with reference to FIG. As shown in FIG. 28, superconducting magnet 100 has refrigerator 110 and magnetic field generator 120 .

The refrigerator 110 has a refrigerator main body 111, an extension part 112, and a cold stage 113, like the refrigerator 6 described in the third embodiment. A magnetic field generator 120 is placed on the cold stage 113 .

The magnetic field generator 120 has an inner superconductor 121 , an outer superconductor 122 , a sample holder 123 , a vacuum insulation container 124 and a room temperature bore container 125 .

The inner superconductor 121 corresponds to the cylindrical superconductor of the present invention. The inner superconductor 121 has the same configuration as the cylindrical superconductor 7A according to the second embodiment, and has a cylindrical substrate 121a and a superconductor 121b. The cylindrical base member 121a has a cylindrical portion and a flange radially extending radially outward from one end (lower end) of the cylindrical portion. be done. A sheet-like superconductor 121b is attached to a concave portion formed in most of the outer peripheral surface of the cylindrical portion of the cylindrical substrate 121a. Thereby, the superconductor 121b is formed in a cylindrical shape.

The outer superconductor 122 is a member that generates a strong magnetic field by trapping an external magnetic field in a superconducting state. The outer superconductor 122 is formed in a cylindrical shape by laminating a plurality of ring-shaped superconducting bulks along the axial direction. The inner superconductor 121 is coaxially arranged on the inner periphery of the cylindrical outer superconductor 122 .

The cylindrical outer superconductor 122 is arranged coaxially with the inner superconductor 121 so that its lower end surface rests on the flange of the cylindrical substrate 121a. A sample holder 123 is arranged with respect to these superconductors so as to cover the outer peripheral surface and upper end surface of the outer superconductor 122 and the upper end surface of the inner superconductor 121 .

The sample holder 123 has a body portion 123a, a flange portion 123b, and a cover portion 123c. The body portion 123a is formed in a cylindrical shape and arranged so as to cover the outer circumference of the outer superconductor 122 . A flange portion 123b is connected to the lower end of the body portion 123a. The flange portion 123 b is formed so as to radially expand radially outward from the lower end of the main body portion 123 a , and the lower surface thereof is fixed to the upper surface of the cold stage 113 . Further, a cover portion 123c is continuously provided to the upper end of the body portion 123a. The cover portion 123c is formed in a circular shape so as to cover the upper end opening of the main body portion 123a, and is arranged so as to cover the upper end surface of the outer superconductor 122 and the upper end surface of the inner superconductor 121 . A circular hole having a diameter substantially equal to the inner diameter of the inner superconductor is formed in the center of the cover portion 123c.

The vacuum insulation container 124 has a body portion 124a, a flange portion 124b, and a cover portion 124c. The body portion 124a has an inner diameter larger than the outer diameter of the cold stage 113 and is formed in a cylindrical shape. The extended portion 112 of the refrigerator 110, the cold stage 113, the inner superconductor 121, the outer superconductor 122, and the sample holder 123 are covered with the main body portion 124a. A flange portion 124b is connected to the lower end of the body portion 124a. This flange portion 124b is fixed to the upper surface of the refrigerator main body 111 of the refrigerator 110 . Further, a cover portion 124c is continuously provided to the upper end of the main body portion 124a. The cover portion 124c is formed in a disc shape so as to cover the upper end opening of the body portion 124a. The cover portion 124 c is positioned slightly above the cover portion 123 c of the sample holder 123 . A circular hole having a smaller diameter than the circular hole formed in the cover portion 123c of the sample holder 123 is formed in the center of the cover portion 124c.

The room temperature bore container 125 has a container portion 125a and a lid portion 125b. The container part 125a has a cylindrical shape with a bottom, and is arranged coaxially with the inner superconductor 121 and the outer superconductor 122 in the inner peripheral space of the inner superconductor 121 with the bottom surface facing downward. The upper end portion of the container portion 125a protrudes upward from a circular hole formed in the cover portion 124c of the vacuum insulation container 124, and a lid portion 125b formed to radially expand from the upper end of the container portion 125a continues. is set. The lid portion 125b is placed on the upper surface of the cover portion 124c of the vacuum insulation container 124. As shown in FIG.

The vacuum insulation container 124 and the room temperature bore container 125 make the upper space of the refrigerator main body 111 a closed space. In this closed space, the extending portion 112 of the refrigerator 110, the cold stage 113, the outer superconductor 122, the inner superconductor 121, and the sample holder 123 are arranged. This enclosed space is evacuated for thermal insulation. The inner peripheral space of the container portion 125a of the room temperature bore container 125 is called a room temperature bore space.

In the superconducting magnet 100 configured as described above, when the refrigerator 110 is driven, the cold stage 113 is cooled, and further the outer superconductor 122 and the inner superconductor 121 placed on the cold stage 113 are cooled. As a result, the outer superconductor 122 and the inner superconductor 121 are cooled to the superconducting critical temperature Tc or less and brought into a superconducting state.

Further, as shown in FIG. 27, an inspection apparatus 1A according to the present embodiment has a configuration in which the outer inspection unit 50 is removed from the inspection apparatus 1 according to Modification 2 shown in FIG. That is, the inspection apparatus 1A includes the inspection unit 40 having the inner Hall element 43 and the inner permanent magnet 45, and does not include the outer inspection unit. The inner inspection unit 40 is then inserted into the room temperature bore space of the superconducting magnet 100 .

As shown in FIG. 28, the inner Hall element 43 of the inner inspection unit 40 inserted into the room-temperature bore space is arranged to extend along the inner circumference of the inner superconductor 121 (cylindrical superconductor) with the container portion 125a of the room-temperature bore container 125 interposed therebetween. Place them facing each other. The inner permanent magnet 45 is arranged to face the inner peripheral surface of the inner superconductor 121 with the inner Hall element 43 and the container portion 125a of the room temperature bore container 125 interposed therebetween. Here, in the present embodiment, the inner permanent magnet 45 is arranged so that its N pole side faces the inner Hall element 43 . In this state, the inner Hall element 43 is swept along the inner peripheral surface of the inner superconductor 121 .

In this embodiment, a magnetic field is applied to the inner superconductor 121 from the north pole of the inner permanent magnet 45 . Since the inner superconductor 121 is rendered superconducting, a shielding current is formed in the inner superconductor 121 to shield the applied magnetic field from the inner permanent magnet 45 . This shields the applied magnetic field, and the shielded magnetic field (shielding magnetic field) is formed between the inner permanent magnet 45 and the inner superconductor 121 in the inner peripheral space of the inner superconductor 121 . Therefore, the inner Hall element 43 between the inner permanent magnet 45 and the inner superconductor 121 detects the shielding magnetic field. Thus, in this embodiment, the inner Hall element 43 functions as a shielding magnetic field detection sensor. The soundness of the superconducting state of the inner superconductor 121 is inspected by detecting the shielding magnetic field while the inner Hall element 43 is being swept (while moving) along the inner peripheral surface of the inner superconductor 121 .

According to this embodiment, the inner superconductor 121 , which is a cylindrical superconductor incorporated in the superconducting magnet 100 for NMR, can be directly inspected through the room temperature bore container 125 . Therefore, the cylindrical superconductor can be inspected without preparing a dedicated refrigerator or vacuum vessel for inspection.

Hereinafter, various modifications for inspecting the soundness of the superconducting state of the cylindrical superconductor 7A cooled by the refrigerator 6 described in the third embodiment will be described.
(Fifth embodiment)
FIG. 29 is a diagram showing an example of inspection using the inspection apparatus according to the fifth embodiment. As shown in FIG. 29, in this embodiment, a magnetic material is formed on the back surface of the inner Hall element 43 (the surface of the inner Hall element 43 opposite to the surface facing the inner peripheral surface of the cylindrical superconductor 7A). A yoke 46 is provided. Also, in this embodiment, although the outer permanent magnet 55 is provided, the outer Hall element is not provided. Other configurations are the same as those of the inspection apparatus 1 shown in the first embodiment.

Since the yoke 46 is provided behind the inner Hall element 43 , the magnetic flux generated from the north pole of the outer permanent magnet 55 and transmitted through, for example, a defect of the cylindrical superconductor 7A concentrates on the yoke 46 . Since the yoke 46 is attached to the back surface of the inner Hall element 43 , the magnetic flux concentrated on the yoke inevitably passes through the inner Hall element 43 . Therefore, the transmitted magnetic field detected by the inner Hall element 43 becomes stronger. In other words, the detection sensitivity is improved, and the presence of even minute defects can be indicated by changes in the strength of the penetrating magnetic field. Therefore, inspection accuracy can be further improved.

(Sixth embodiment)
FIG. 30 is a diagram showing an example of inspection using the inspection apparatus according to the sixth embodiment. As shown in FIG. 30, in the inspection apparatus according to this embodiment, a yoke 46 is provided on the back surface of the inner Hall element 43, as in the fifth embodiment. An outer Hall element 53 is provided between the outer permanent magnet 55 and the cylindrical superconductor 7A. Other configurations are the same as those of the inspection apparatus 1 described in the first embodiment.

In this embodiment, as in the fifth embodiment, the magnetic flux passing through the defects of the cylindrical superconductor 7A concentrates on the yoke 46 provided on the back surface of the inner Hall element 43. FIG. Therefore, the detection sensitivity of the inner Hall element 43 and the outer Hall element 53 is improved, and the inspection accuracy can be improved. Further, similarly to the first embodiment, the inner Hall element 43 can simultaneously detect the penetrating magnetic field and the outer Hall element 53 can simultaneously detect the shielding magnetic field.

(Seventh embodiment)
FIG. 31 is a diagram showing an example of inspection using the inspection apparatus according to the seventh embodiment. In this embodiment, an inspection device similar to the inspection device 1A shown in FIG. 27 described in the fourth embodiment is used. Therefore, the inspection apparatus according to this embodiment includes the inner inspection unit 40 but does not include the outer inspection unit.

Moreover, in the inspection apparatus according to this embodiment, the inner inspection unit 40 has the first inner Hall element 43A and the second inner Hall element 43B. The first inner Hall element 43A corresponds to the first sensor of the present invention, and the second inner Hall element 43B corresponds to the second sensor of the present invention. The first inner Hall element 43A has a magnetic sensing part 43a1 and is provided between the N pole surface of the inner permanent magnet 45 provided in the inner inspection unit 40 and the cylindrical superconductor 7A. The second inner Hall element 43B has a magnetically sensitive portion 43a2 and is provided between the S pole surface of the inner permanent magnet 45, that is, the pole surface opposite to the N pole surface and the cylindrical superconductor 7A. A first inner spacer 44A is arranged between the N pole surface of the inner permanent magnet 45 and the first inner Hall element 43A, and between the S pole surface of the inner permanent magnet 45 and the second inner Hall element 43B. A second inner spacer 44B is provided. 31, the inner permanent magnet 45 is embedded in the inner rod portion 41 such that the N pole surface and the S pole surface are exposed in mutually opposite directions from the outer peripheral surface of the inner rod portion 41. can be configured by Other configurations of the inspection apparatus according to this embodiment are the same as those of the inspection apparatus 1A described in the fourth embodiment.

According to this embodiment, the first inner Hall element 43A detects the shielding magnetic field in the examination area facing it, and the second inner Hall element 43B detects the shielding magnetic field in the examination area facing it. That is, shielding magnetic fields in two inspection regions can be detected at the same time. Therefore, the inspection time can be shortened. Even when the S pole surface of the inner permanent magnet 45 faces the cylindrical circumferential surface of the cylindrical superconductor 7A as in the present embodiment, the N pole surface is the cylindrical circumferential surface of the cylindrical superconductor 7A. Shielding and penetrating magnetic fields can be detected in the same way as when facing the .

(Eighth embodiment)
FIG. 32 shows an example of inspection using the inspection apparatus according to the eighth embodiment. In this embodiment, a yoke 56 is attached to the north pole face of the outer permanent magnet 55 for concentrating the magnetic flux. Other configurations are the same as those of the inspection apparatus 1 according to the first embodiment.

According to this embodiment, the magnetic field generated from the north pole surface of the outer permanent magnet 55 is concentrated on the yoke 56 and thus concentrated on the inspection area of the cylindrical superconductor 7A. Therefore, more magnetic flux passes through the outer Hall element 53 and the inner Hall element 43 when defects are present. Therefore, when a defect exists, the shielding magnetic field and the penetrating magnetic field are stronger, and detection sensitivity and position resolution are improved. As a result, inspection accuracy is further improved.

(Ninth embodiment)
FIG. 33 shows an example of inspection using the inspection apparatus according to the ninth embodiment. In this embodiment, instead of the outer permanent magnet 55, an outer coil 57 is provided. Other configurations are the same as those of the inspection apparatus 1 according to the first embodiment.

According to this embodiment, the magnitude of the magnetic field applied from the outer coil 57 to the cylindrical superconductor 7A can be adjusted by controlling the amount of electricity supplied to the outer coil 57. FIG. Therefore, by changing the energization amount and the energization direction to the outer coil 57, the optimum inspection conditions can be set. In addition, when the current supplied to the outer coil 57 is small and the generated magnetic field is small, the presence or absence of defects on the surface of the cylindrical superconductor 7A and the non-uniformity of the critical current density Jc are evaluated, that is, the surface of the cylindrical superconductor 7A A layer sanity check can be performed. Also, when the applied current is made very large and the generated magnetic field is made very large, the magnetic field gradually penetrates from the surface of the cylindrical superconductor 7A into its interior. Therefore, it is possible to inspect not only the surface of the cylindrical superconductor 7A but also the soundness of the superconducting state inside the cylindrical superconductor 7A (presence of defects and non-uniformity of the critical current density Jc).

Although various embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, in the above-described first embodiment, the outer Hall element 53 detects the shielding magnetic field and the inner Hall element 43 detects the permeation magnetic field. You may configure the inspection device in Also, in the ninth embodiment, an example using the outer coil 57 has been described, but an electromagnet may be used instead of the coil. Further, the outer Hall element 53 and the outer permanent magnet 55 may be attached to the outer inspection unit 50 and the inner Hall element 43 and the inner permanent magnet 55 may be attached to the inner inspection unit 40 . In other words, magnets may be provided on both the inner and outer peripheral sides of the cylindrical superconductor. In this case, the states of the shielding magnetic field and the penetrating magnetic field become complicated, but since the shielding magnetic field and the penetrating magnetic field change depending on the presence or absence of defects, even with this configuration, the soundness of the cylindrical superconductor can be maintained. sex can be tested. In this manner, the present invention can be modified without departing from its gist.

DESCRIPTION OF SYMBOLS 1, 1A... Inspection apparatus, 6... Refrigerator, 7, 7A... Cylindrical superconductor, 71, 71A... Cylindrical base material, 72... Inner superconducting layer, 73... Outer superconducting layer, 74... Superconductor, 10... Manual lifting Operation unit 20 Axial movement unit 25 Axial movement stage 30 Rotation unit 33 Rotation stage 40 Inner inspection unit 41 Inner rod 42 Inner inspection plate 43 Inner Hall element (transmission magnetic field detection sensor, shielding magnetic field detection sensor), 43A... first inner Hall element (first sensor), 43B... second inner Hall element (second sensor), 44... inner spacer, 45... inner permanent magnet (magnet ), 46... Yoke, 50... Outer inspection unit, 51... Outer rod portion, 52... Outer inspection plate, 53, 531... Outer Hall element (shielding magnetic field detection sensor, permeation magnetic field detection sensor), 532... First outer Hall element , 533... Second outer Hall element, 54... Outer spacer, 55... Outer permanent magnet (magnet), 56... Yoke, 57... Outer coil (magnet), 81... Container, 100... Superconducting magnet, 110... Refrigerator, 120 Magnetic field generator 121 Inner superconductor (cylindrical superconductor) 121a Cylindrical substrate 121b Superconductor 122 Outer superconductor 123 Sample holder 124 Vacuum insulation container 125 Room temperature bore container , B1, B2... Spiral boundary, D... Defect, R... Inspection area

Claims (14)

a shielding magnetic field detection sensor arranged facing the cylindrical peripheral surface of the cylindrical superconductor brought into a superconducting state;
an axial movement unit configured to move the shielding magnetic field detection sensor along the axial direction of the cylindrical superconductor;
a rotation unit configured to rotate the shielding magnetic field detection sensor around the central axis of the cylindrical superconductor;
It has two different magnetic poles, one magnetic pole is disposed at a position facing the cylindrical peripheral surface of the cylindrical superconductor with the shielding magnetic field detection sensor interposed therebetween, and is movable together with the shielding magnetic field detection sensor to detect the shielding magnetic field. a magnet connected to the sensor;
with
The shielding magnetic field detection sensor detects a shielding magnetic field formed by shielding the magnetic field applied from the one magnetic pole of the magnet to the cylindrical superconductor by the cylindrical peripheral surface of the cylindrical superconductor. inspecting the soundness of the superconducting state within the cylindrical circumferential surface of the cylindrical superconductor by detecting it while moving along the cylindrical circumferential surface of the cylindrical superconductor by driving the directional movement unit and the rotating unit; A cylindrical superconductor inspection apparatus configured to be able to In the cylindrical superconductor inspection apparatus according to claim 1,
The magnet and the shielding magnetic field detection sensor are arranged in the inner peripheral space of the cylindrical superconductor,
The shielding magnetic field detection sensor is arranged facing the inner peripheral surface of the cylindrical superconductor,
A cylindrical superconductor inspection apparatus, wherein the magnet is disposed at a position where the one magnetic pole faces the inner peripheral surface of the cylindrical superconductor with the shielding magnetic field detection sensor interposed therebetween. In the cylindrical superconductor inspection apparatus according to claim 2,
The shielding magnetic field detection sensor has a first sensor and a second sensor,
The magnet has one magnetic pole facing the inner peripheral surface of the cylindrical superconductor with the first sensor sandwiched therebetween, and the other magnetic pole of the magnet sandwiches the second sensor and the cylindrical superconductor. It is arranged at a position facing the inner peripheral surface of the
The first sensor detects a shielding magnetic field formed when the magnetic field applied from the one magnetic pole to the cylindrical superconductor is shielded by the cylindrical peripheral surface of the cylindrical superconductor, and the second sensor detects is a cylindrical superconductor inspection apparatus for detecting a shielding magnetic field formed by the magnetic field applied to the cylindrical superconductor from the other magnetic pole being shielded by the cylindrical peripheral surface of the cylindrical superconductor. In the cylindrical superconductor inspection apparatus according to claim 1,
The magnet and the shielding magnetic field detection sensor are arranged in the outer peripheral space of the cylindrical superconductor,
The shielding magnetic field detection sensor is arranged facing the outer peripheral surface of the cylindrical superconductor,
The magnet is disposed at a position where the one magnetic pole faces the outer peripheral surface of the cylindrical superconductor with the shielding magnetic field detection sensor interposed therebetween. a transmission magnetic field detection sensor arranged facing the cylindrical peripheral surface of the cylindrical superconductor brought into a superconducting state;
an axial movement unit configured to move the transmission magnetic field detection sensor along the axial direction of the cylindrical superconductor;
a rotation unit configured to rotate the transmission magnetic field detection sensor around the central axis of the cylindrical superconductor;
It has two different magnetic poles, one of which is disposed at a position facing the transmission magnetic field detection sensor across the cylindrical peripheral surface of the cylindrical superconductor, and the transmission magnetic field is movable together with the transmission magnetic field detection sensor. a magnet connected to the detection sensor;
with
The transmitted magnetic field detection sensor detects a transmitted magnetic field formed by the magnetic field applied from the one magnetic pole of the magnet to the cylindrical superconductor passing through the cylindrical peripheral surface of the cylindrical superconductor in the axial direction. inspecting the soundness of the superconducting state within the cylindrical circumferential surface of the cylindrical superconductor by detecting the superconducting state while moving along the cylindrical circumferential surface of the cylindrical superconductor by driving the moving unit and the rotating unit; A cylindrical superconductor inspection apparatus configured to be able to In the cylindrical superconductor inspection apparatus according to claim 5,
A cylindrical superconductor inspection apparatus, wherein a yoke is provided on the back surface of the transmission magnetic field detection sensor. In the cylindrical superconductor inspection apparatus according to claim 5 or 6,
disposed between the magnet and the cylindrical superconductor, facing the transmitted magnetic field detection sensor across the cylindrical surface of the cylindrical superconductor, and driving the axially moving unit and the rotating unit A shielding magnetic field detection sensor configured to be movable together with the transmission magnetic field detection sensor by
The shielding magnetic field detection sensor detects a shielding magnetic field formed by shielding the magnetic field applied from the one magnetic pole of the magnet to the cylindrical superconductor by the cylindrical peripheral surface of the cylindrical superconductor. The soundness of the superconducting state within the cylindrical circumferential surface of the cylindrical superconductor is inspected by detecting the superconducting state while moving along the cylindrical circumferential surface of the cylindrical superconductor by driving the directional movement unit and the rotating unit. A cylindrical superconductor inspection apparatus configured as follows. In the cylindrical superconductor inspection apparatus according to any one of claims 1 to 7,
A cylindrical superconductor inspection apparatus, wherein a yoke is provided for focusing a magnetic field on said one magnetic pole of said magnet. In the cylindrical superconductor inspection apparatus according to any one of claims 1 to 8,
A cylindrical superconductor inspection apparatus, wherein the magnet is a permanent magnet. In the cylindrical superconductor inspection apparatus according to any one of claims 1 to 8,
A cylindrical superconductor inspection apparatus, wherein the magnet is a coil or an electromagnet. In the cylindrical superconductor inspection apparatus according to any one of claims 1 to 10,
The cylindrical superconductor includes a cylindrical substrate formed in a cylindrical shape,
a superconducting layer formed in a cylindrical shape by spirally winding a superconducting wire on the inner peripheral surface or the outer peripheral surface of the cylindrical substrate;
with
The axial movement unit and the rotation unit control such that the shielding magnetic field detection sensor and/or the transmission magnetic field detection sensor move on the cylindrical circumferential surface of the cylindrical superconductor along the spiral winding direction of the superconducting wire. An inspection device for cylindrical superconductors. A shielding magnetic field detection sensor arranged facing the cylindrical peripheral surface of a cylindrical superconductor in a superconducting state, and two different magnetic poles, one magnetic pole sandwiching the shielding magnetic field detection sensor and the cylindrical peripheral surface of the cylindrical superconductor. a sweeping step of sweeping the magnet disposed at a position facing the cylindrical superconductor in the axial direction and the circumferential direction;
The shielding magnetic field detection sensor sweeps the shielding magnetic field formed when the magnetic field applied from the one magnetic pole of the magnet to the cylindrical superconductor is shielded by the cylindrical peripheral surface of the cylindrical superconductor. A shielding magnetic field detection step of detecting while being swept in the step;
A method for inspecting a cylindrical superconductor, comprising: A transmission magnetic field detection sensor arranged facing the cylindrical peripheral surface of a cylindrical superconductor in a superconducting state, and a transmission magnetic field detection sensor having two different magnetic poles, one magnetic pole sandwiching the cylindrical peripheral surface of the cylindrical superconductor. A sweep step of sweeping the magnet arranged at a position facing the cylindrical superconductor in the axial direction and the circumferential direction;
The transmitted magnetic field detection sensor detects, in the sweep step, a transmitted magnetic field formed by a magnetic field applied from one magnetic pole of the magnet to the cylindrical superconductor being transmitted through the cylindrical peripheral surface of the cylindrical superconductor. a penetrating magnetic field detection step of detecting while being swept by
A method for inspecting a cylindrical superconductor, comprising: In the method for inspecting a cylindrical superconductor according to claim 12 or 13,
The cylindrical superconductor includes a cylindrical substrate formed in a cylindrical shape,
a superconducting layer formed in a cylindrical shape by spirally winding a superconducting wire on the inner peripheral surface or the outer peripheral surface of the cylindrical substrate;
with
In the sweeping step, the shielding magnetic field detection sensor and/or the transmission magnetic field detection sensor are swept so as to move along the cylindrical peripheral surface of the cylindrical superconductor along the spiral winding direction of the superconducting wire, Inspection method for cylindrical superconductors.

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