JP3021970B2 - Functional superconducting magnetic shield and magnetometer using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a functional superconducting magnetic shield and a functional superconducting magnetic shield which are particularly suitable for shielding magnetic noise of a biomagnetism detecting device for detecting a magnetic field generated from a living body. The present invention relates to a magnetometer combined with a SQUID (superconducting quantum interferometer) magnetometer.

[0002]

2. Description of the Related Art A conventional biomagnetism detecting device is disclosed, for example, in Review of Scientific Instruments, Vol.
No., (1982), pp. 1815-1845 (Rev. Sci.
Instrum., Vol.53, No.12, 1982 pp.1815-1845). FIG. 6 schematically shows this conventional example. Biomagnetic field,
In particular, the magnetic field generated from the brain is as small as one hundred millionth of geomagnetism. Therefore, in order to shield magnetic noise due to disturbance, the biomagnetism detection device is placed in a magnetically shielded room 200 made of a ferromagnetic material (permalloy) together with the subject. The magnetic shielding ratio of the Permalloy magnetic shield room, that is, the ratio of the internal magnetic field to the external magnetic field is about 1/1000, which is generally used.

[0003] The SQ, which is a detector part of a biomagnetism measuring device,
A magnetometer utilizing a UID (superconducting quantum interferometer) generally includes a differential detection coil 21 for detecting a biological signal, an input coil 22 for transmitting the signal to a SQUID, and a high-sensitivity magnetic flux.
SQUID 30 as voltage conversion element, feedback modulation coil 2
3 and a drive circuit. The detection coil, input coil, feedback modulation coil, and SQUID are superconductors, and the magnetic shield 100 of the superconductor covers the SQUID, the input coil, and the feedback modulation coil.

[0004] The role of the magnetic shield of the superconductor is to prevent malfunction of the SQUID due to external magnetic noise. Further, the role of the differential detection coil is to selectively detect a signal from magnetic noise that is still about 1000 times the signal magnetic field in the permalloy magnetic shield room 200. FIG. 6 illustrates a primary differential detection coil as the differential detection coil. The first-order differential detection coil has a configuration in which two one-turn coils wound in opposite directions and an input coil form a single superconducting closed loop, and only the difference between the magnetic flux applied to the two one-turn coils is obtained. Is SQUID
To communicate. Here, a noise magnetic field having a magnetic field source in the distance has the same amount of magnetic flux applied to the two coils, and a biomagnetic field having a magnetic field source in the vicinity causes a difference in the amount of magnetic flux applied to the two coils. Therefore, the signal is selectively detected. be able to.

In the above-described conventional biomagnetism detecting device, the input coil, the feedback modulation coil, and the SQUID (inside the dotted line 31) are generally formed as a single thin film to improve magnetic coupling. On the other hand, a method of forming a detection coil by winding a niobium-titanium wire around a quartz tube or a method of forming a thin film on a flexible substrate (for example, JP-A-122584) is known. Requires the superconducting coupling part 60. In addition, the SQUIS having such a configuration
In the D magnetometer, the magnetic flux detected by the differential detection coil and the SQUA
The ratio of the magnetic flux transmitted to the ID (magnetic flux transmission rate) is generally 0.
However, there is a problem that the magnetic flux transmission rate is so small that magnetism cannot be detected with high sensitivity. In order to solve this problem, a direct coupling type SQUID magnetometer that does not use a detection coil has also been proposed (see IEE Transactions on Magnetics 2).
7, No. 2, (1991), pp. 2793-2796 (IE
EETransactions on Magnetics, Vol.27, No2,1991 pp.279
3-2796)) There is a problem that a high magnetic shielding ratio of about 1/10000 to / 100,000 is required for a magnetic shielding room of Permalloy.

[0006]

As described above, the SQUID magnetometer having the detection coil requires a highly reliable superconducting coupling portion between the detection coil and the input coil, and the configuration is complicated. In addition, when replacing the detection coil, it is necessary to remove the superconducting coupling portion and join it again. Further, there is a problem that the magnetic flux transmission efficiency is very small, about 0.01. An object of the present invention is to provide a SQUID magnetometer operating in a permalloy magnetic shield having a magnetic shielding ratio of about 1/1000, without using a detection coil, eliminating a superconducting coupling portion and improving a magnetic flux transmission rate. It is to provide a conductive magnetic shield. Particularly, a functional superconducting magnetic shield, a functional superconducting magnetic shield and a SQUID (superconducting quantum interferometer) magnetometer suitable for shielding magnetic noise of a biomagnetism detecting device for detecting a magnetic field generated from a living body. Combined magnetometers may be provided.

[0007]

In order to achieve the above object, a predetermined space on a plane or a curved surface is formed by surrounding a predetermined space with a superconductor, and surrounds two spaces having the same area, respectively. Two superconducting enclosures (for example, a ring) are connected by a superconducting body so that the winding direction is the same when viewed as a coil, and a single superconducting closed loop is formed as a whole. Construct a functional superconducting magnetic shield. In addition, the SQUID is arranged in close contact with the highest S / N position of the superconducting magnetic shield, for example, one of the rings. That is, the functional superconducting magnetic shield is formed by surrounding a predetermined space on a plane or a curved surface with a superconductor, and two superconducting enclosures respectively surrounding two spaces having the same area, It comprises a superconducting connector that connects the two superconducting enclosures, forms a single superconducting closed loop as a whole, and selectively shields a noise magnetic field. The superconducting connector is formed such that the winding directions of the superconductors forming the two superconducting enclosures are equal, and the distance between the two superconducting enclosures is 3 which is the outermost dimension of the superconducting enclosure. More than double. In the functional superconducting magnetic shield, the superconducting enclosure is formed by winding a niobium-titanium wire around a quartz tube or by a flexible substrate. The shape of the space surrounded by the superconducting enclosure is a circle, a triangle, a polygon having at least four sides, and a regular polygon.

The SQUID magnetometer is placed on the functional superconducting magnetic shield in close contact with one surface of the superconducting enclosure,
The shape of the outer portion of the magnetic detection section made of the superconductor of the UID magnetometer is made equal to the shape of the superconducting enclosure, and the shortest of the superconductor forming the magnetic detection section and the superconductor forming the superconducting enclosure The distance is smaller than the largest dimension of the cross section of any of these superconductors. The superconductor in the outer portion of the magnetic detection unit and the superconductor forming the superconducting enclosure are arranged so that at least a part of the superconductors are continuously overlapped in the outer portion. The SQUID magnetometer is, for example, a direct coupling type S having a structure in which a SQUID ring is divided in parallel.
QUID. Also, the functional superconducting magnetic shield,
One end and the other end of the spiral superconductor formed in the axial direction of the column while the superconductor is wound along the column are connected outside the spiral superconductor, and It is characterized by forming a single superconducting closed loop and selectively shielding a noise magnetic field. In this functional superconducting magnetic shield, a direct coupling type SQUID magnetometer having a structure in which the SQUID ring is divided in parallel is provided with one plane perpendicular to the axis of the helical superconductor, including a plane including the magnetic detection unit. Arrange a plurality. The shape of the cross section perpendicular to the axis of the columnar body is any one of a circle, a triangle, a polygon having at least four sides, and a regular polygon.

[0009]

The magnetic flux penetrating the two rings constituting the functional superconducting magnetic shield of the present invention will be described below. When the magnetic field source is far away, the magnetic shielding due to the Meissner effect is equal in the two rings because the amount of magnetic flux applied to the two rings is equal. On the other hand, when the magnetic field source is in the vicinity and the distance to the ring is different between the two rings, the amount of magnetic flux applied to the two rings is different, so that the difference magnetic flux does not penetrate the ring. Works. As in the case of the first derivative coil, if the distant magnetic field source is considered as a noise source and the nearby magnetic field source is considered as a signal source, the functional superconducting magnetic shield has a distribution of signal magnetic field and noise magnetic field inside or around the shield. Has occurred. Here, the signal magnetic field can be selectively detected by arranging the magnetic detector of the SQUID magnetometer at the position where the ratio of the signal magnetic field to the noise magnetic field is the highest. This SQUID arrangement does not require superconducting coupling,
It is highly reliable and easy to remove. Further, since no detection coil is required, the magnetic flux transmission rate is also improved. In summary, while the conventional magnetic shield of superconductor shields both the signal magnetic field and the noise magnetic field, the functional superconductive magnetic shield of the present invention has the function of selectively shielding the noise magnetic field. There are features.

[0010]

FIG. 1 shows an embodiment of a functional superconducting magnetic shield according to the present invention. Two annular superconductors 11, 12
Are connected by a superconducting connection 13 to form a single superconducting closed loop and form a functional superconducting magnetic shield 10. Here, the directions of the currents flowing with respect to the magnetic field in the same direction are connected in the same direction in each of the rings. Functional superconducting magnetic shield 1 shown by a solid line in FIG.
As a manufacturing method of No. 0, a niobium-titanium wire may be wound around a quartz tube, or a film may be formed on a flexible substrate and bent. In FIG. 1, the dotted line is a cylinder, the two annular superconductors 11 and 12 are perpendicular to the central axis of the cylinder, and the cross-sectional area is equal to the cross-sectional area of the cylinder, and the superconducting connection 13 is on the outer surface of the cylinder ( In FIG. 1, the circles of the dotted line and the solid line are consciously changed in diameter for easy understanding of the shape.) In FIG. 1, a superconductor surrounds a circular planar space, and two superconducting enclosures 11 and 12 are formed. The space surrounded by the superconducting enclosure is not limited to a circle, but may be two spaces having the same area formed by surrounding a space on a predetermined plane or a curved surface with a superconductor. Needless to say. The shape of the superconducting enclosure may be arbitrary,
For example, a polygon such as a triangle, 4, 6, or octagon, or a regular polygon is used. In particular, in a multi-channel magnetometer, a large number of magnetometers, each of which combines a functional superconducting magnetic shield and a SQUID magnetometer, are densely arranged.
It is desirable to use a regular polygon such as a quadrangle and a hexagon.

Also, needless to say, the functional superconducting magnetic shield of the present invention is immersed in a cryogen such as liquid helium or liquid nitrogen as required. One of the rings of the functional superconducting magnetic shield shown in FIG. 1 is brought close to the subject. Here, the sum of the noise magnetic flux An1 and the signal magnetic flux As1 is added to the ring 11 close to the subject, and the sum of the noise magnetic flux An2 and the signal magnetic flux As2 is added to the ring 12 far from the subject. In this case, a current flows in a closed loop due to the Meissner effect of the superconducting magnetic shield, and as a sum of the magnetic flux due to the loop current and the applied magnetic flux, the magnetic flux penetrating through a ring far from the subject and a circle near the subject are as follows. (Figure 1
Let the upward direction be the + direction. )

[0012]

(An1-An2) / 2 + (As1-As2) / 2- (An1-An2) / 2- (As1-As2) / 2 (1) The value of (An1-An2) is primary. Like the differential coil, the accuracy of the difference between the areas of the ring 11 and the ring 12 depends on the accuracy of the inclination of the two rings in the plane direction, and the actual value is usually (An1-An2) ≒ An is about 1/1000. As an extreme case, if An1 = An2 and As2 = 0,

[0013]

## EQU2 ## In a ring close to the subject: + As1 / 2 In a ring far from the subject: -As1 / 2 (Formula 2) As described above, when the functional superconducting magnetic shield of the present invention is used, it can be understood that the S / N of the magnetic flux in the vicinity of any ring is improved by about 1000 times. In order for the above operation to be performed sufficiently, it is necessary that the distortion of the magnetic field due to one ring does not affect the other ring.
For this purpose, the distance between the two rings (hereinafter referred to as the baseline in contrast to the first derivative coil) is at least three times the diameter of the ring, ie the distance between the two superconducting enclosures is More than three times the outermost dimension of the body is sufficient.

Next, the configuration of a SQUID magnetometer using a functional superconducting magnetic shield according to the present invention will be described. SQUI
D is the direct coupling type SKU described in the prior art
It is appropriate to use the ID (FIG. 3). The direct coupling type SQUID has a structure in which a so-called SQUID ring directly detects a magnetic field. In order to prevent the self-inductance of the SQUID ring from becoming excessive, a SQUID is used.
It has a structure in which rings are divided in parallel. The direct coupling type SQUID 32 is arranged in close contact with one of the rings 12 as shown in FIG. At this time, the ring 1
In order to detect the magnetic flux penetrating through the SQUID 2 as much as possible, as shown in the partially enlarged sectional view of FIG.
Is located between the inner end position 37 and the outer end position 38 of the superconductor 36 of the ring 12. For example, as shown in this figure, the shape of the magnetic detection unit of the direct coupling type SQUID 32 is equal to the shape of the superconducting enclosure, and the direct coupling type
The width of the superconductor 33 in the outer part of the UID 32 is smaller than the width of the superconductor 36 in the ring 12, and the superconductor 33 in the outer part of the direct coupling type SQUID 32 is
It is sufficient that the superconductor 36 overlaps the superconductor 36. Further, the superconductor in the outer portion of the magnetic detection unit of the direct coupling type SQUID and the superconductor forming the superconducting enclosure are:
It suffices that at least a part of these superconductors be continuously arranged at the outer portion so as to overlap. Further, the shortest distance between the superconductor forming the magnetic detection unit of the direct coupling type SQUID32 and the superconductor forming the superconducting enclosure is equal to the superconductor forming the magnetic detection unit of the direct coupling type SQUID32. The superconductors forming the conductive enclosure are brought into close contact with each other so as to be smaller than the maximum dimension of any of the cross sections. With this configuration, the S / N of the magnetic flux passing through the SQUID ring is improved by about 1000 times as compared with the case without the functional superconducting magnetic shield. Therefore, the present SQUID magnetometer can be used in a general shielded room having a shielding ratio of about 1/1000. Moreover, direct coupling type S
The advantage that the magnetic flux transmission rate of the QUID is high is utilized.
From Equation 1, the magnetic flux transmission rate is 0.5.

In the SQUID magnetometer of FIG. 2, the functional superconducting magnetic shield according to the present invention plays a role similar to that of a conventional primary differential coil. However, magnetic shield and SKU
No superconducting coupling is required between the IDs. The conventional superconducting junction between the differential coil and the SQUID is generally a dissimilar metal junction. For example, when a superconductor such as lead or niobium is used, it is stable against a thermal cycle between room temperature and liquid helium temperature. Therefore, high reliability was required. In this embodiment, since the superconducting coupling portion is not required, the device is simplified, and the reliability is greatly improved. Also, when replacing with a functional superconducting magnetic shield having a different baseline as necessary, the present invention does not have a superconducting coupling part, so there is no need to detach and attach the superconducting coupling part as in the conventional case, which is simple and convenient. Yes, and can maintain reliability. Next, an embodiment of a multi-channel biomagnetism measuring apparatus using a functional superconducting magnetic shield according to the present invention is shown in FIG. In this figure, the main part of the invention is shown in an enlarged manner. 37 SQUID magnetometers having the same principle as shown in FIG. 2 are arranged in a plastic low temperature tank (Dewar) 70. In addition, Dewa has a Permalloy magnetic shield 20 with the subject.
It is put in 0. In this embodiment, the direct coupling type SQUID 32 is arranged on the bottom surface of the dewar, and the line for supplying the bias current and applying the feedback modulation magnetic flux and the signal line 90 are connected from the bottom surface of the dewar to the room temperature along the wall surface. The functional superconducting magnetic shield 10 of the present invention is disposed in close contact with the direct coupling type SQUID 32 on the bottom surface. Here, the direct coupling type SQUID has a hexagonal shape to improve symmetry,
The shape of the functional superconducting magnetic shield is also a hexagonal prism. In this figure, the functional superconducting magnetic shield 10 shows the arrangement of a part of the required number 37. According to the present embodiment, there is an effect that the baseline can be easily changed in the biomagnetism measuring device according to the measurement target site and the environmental noise. For example, in the case of measurement in the case of a cardiac magnetic field having a larger signal amount than environmental noise, the functional superconducting magnetic shield is removed and used as a magnetometer. When the signal source is deep in brain magnetic field measurement, a functional superconducting magnetic shield with a long baseline is used. If the signal source is shallow, a functional superconducting magnetic shield with a short baseline is used. These changes can be made without removing the superconducting coupling. In this embodiment, even if the functional superconducting magnetic shield and the direct coupling type SQUID are turned upside down, there is no functional change.

Another embodiment of the structure of the functional superconducting magnetic shield is shown in FIG. The spiral superconducting wire forms a single superconducting closed loop, and the upper and lower ends are connected to form a single superconducting closed loop. There is a distribution of a signal magnetic field and a noise magnetic field inside. Among them, one direct coupling type SQUID 32 is arranged at a high S / N position. Here, the plane including the magnetic detection unit of the direct coupling type SQUID is perpendicular to the axis of the spiral. Although the functional superconducting magnetic shield shown in FIG. 5 has a spiral shape, the superconductor is wound along the column and advances in the axial direction of the column while one of the spiral superconductors is formed. The end and the other end are connected outside the helical superconductor to form a single superconducting closed loop, and the shape of the cross section perpendicular to the axis of the column has a circle, a triangle, and at least four sides. Any of a polygon and a regular polygon may be used, and the cross section may be arbitrary. In this embodiment, S
The position where the QUID is arranged can be freely selected, and a plurality of SQUIDs can be placed in one functional superconducting magnetic shield.
The effect is that measurement can be performed simultaneously at a plurality of points by disposing the. Needless to say, multi-channel biomagnetic measurement can be performed using a plurality of the functional superconducting magnetic shields of the present embodiment. Further, it goes without saying that the magnetometer combining the functional superconducting magnetic shield and the direct coupling type SQUID according to the present invention can be applied not only to biomagnetic measurement but also to detection of various kinds of extremely small magnetism.

[0017]

As described above, according to the present invention,
In a SQUID magnetometer operated in a permalloy magnetic shield having a magnetic shielding ratio of about 1/1000, there is an effect that a so-called detection coil becomes unnecessary and a superconducting coupling part becomes unnecessary. This simplifies the configuration of the device and greatly improves reliability. In addition, there is an effect that the signal magnetic flux input to the SQUID is increased to about 50 times that of the related art.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a functional superconducting magnetic shield according to one embodiment of the present invention.

FIG. 2 is a graph showing the relationship between S and S using the functional superconducting magnetic shield of the present invention.
FIG. 2A is a perspective view showing a QUID magnetometer, and FIG. 2B is a partially enlarged cross-sectional view in a direction perpendicular to a plane formed by the ring.

FIG. 3 is a graph showing the relationship between S and S using the functional superconducting magnetic shield of the present invention.
Direct coupling type SQ suitable for QUID magnetometer
The top view of UID.

FIG. 4 is a perspective view showing one embodiment of a multi-channel biomagnetism measuring apparatus using the functional superconducting magnetic shield of the present invention.

FIG. 5 is a perspective view showing a functional superconducting magnetic shield according to another embodiment of the present invention.

FIG. 6 is a configuration diagram showing a conventional SQUID magnetometer.

[Explanation of symbols]

10 ... Functional superconducting magnetic shield, 11, 12, ring,
13 ... connection, 21 ... detection coil, 22 ... input coil, 2
3: feedback modulation coil, 30: SQUID, 31: SQUI
ID, 32 ... direct coupling type SQUID, 3
3 ... superconductor in the outer part of the direct coupling type SQUID, 34 ... inner end position, 35 ... outer end position, 36
... annular superconductor, 37 ... inner end position, 38 ... outer end position, 60 ... superconducting joint part, 70 ... low temperature tank (Dewa), 9
0: line for supplying bias current and application of feedback modulation magnetic flux and signal line; 100: conventional superconducting magnetic shield; 200: ferromagnetic shield.

Claims (25)

(57) [Claims] A predetermined space on a plane or a curved surface is defined as a superconductor.
And two spaces with the same area
Two superconducting enclosures each surrounding the two superconducting
It consists of a superconducting connector that connects the enclosures, and one
Features a superconducting closed loop and shields noise magnetic fields
Functional superconducting magnetic shield. 2. The functional superconducting magnetic seal according to claim 1.
The superconducting material forming the two superconducting enclosures
The superconducting coupler is shaped so that the winding directions of the bodies are equal.
Functional superconducting magnetic shield characterized by being made. 3. The functional superconducting magnetic seal according to claim 1.
The distance between the two superconducting enclosures is
Characterized in that it is at least three times the outermost dimension of the superconducting enclosure
Functional superconducting magnetic shield. 4. The functional superconducting magnetic seal according to claim 1.
The superconducting enclosure is placed in a quartz tube with niobium-titanium.
Functional super-characteristics formed by winding wire
Conductive magnetic shield. 5. The functional superconducting magnetic seal according to claim 1.
The superconducting enclosure is a flexible substrate
Functional superconducting magnetic seal characterized by being formed
De. 6. The functional superconducting magnetic seal according to claim 1.
The shape of the space that the superconducting enclosure surrounds
But circles, triangles, polygons with at least four sides, few
It is at least one of regular polygons with four sides
Functional superconducting magnetic shield. 7. A predetermined space on a plane or a curved surface is defined by a superconductor.
And two spaces with the same area
Two superconducting enclosures each surrounding the two superconducting
It consists of a superconducting connector that connects the enclosures , and one
Form a superconducting closed loop, forming the two superconducting enclosures
The superconductor so that the winding directions of the superconductors are equal.
A link is formed and the distance between the two superconducting enclosures
Is at least three times the outermost dimension of the superconducting enclosure,
Functional superconducting magnetic sheet characterized by shielding magnetic field
Ludo. 8. The functional superconducting magnetic seal according to claim 1.
SQUID magnetometer on one side of the superconducting enclosure
A magnetometer characterized by being closely mounted. 9. The magnetometer according to claim 8, wherein said S
Outer part of the magnetic detection part consisting of a superconductor of the QUID magnetometer
The shape of the minute is equal to the shape of the superconducting enclosure.
And a magnetometer. 10. The magnetometer according to claim 8, wherein said magnetometer comprises:
Forming a superconductor forming a magnetic detecting portion and the superconducting enclosure;
The shortest distance between the superconductors
A magnetometer characterized by being smaller than the maximum dimension of the surface. 11. The magnetometer according to claim 8, wherein said magnetometer comprises:
The superconductor of the outer part of the magnetic detection unit and the superconducting enclosure are
The superconductor to be formed is continuously connected to the superconductor at the outer portion.
That at least a portion of the conductor
Features magnetic flux meter. 12. The magnetometer according to claim 8, wherein
Outer shell of magnetism detecting part consisting of superconductor of SQUID magnetometer
The shape of the portion is equal to the shape of the superconducting enclosure,
Forming a superconductor and a superconducting enclosure forming an air detector
The shortest distance of the superconductor is determined by any cross section of the superconductor.
A magnetometer characterized by being smaller than the maximum dimension of 13. The magnetometer according to claim 8, wherein said magnetometer comprises:
Outer shell of magnetism detecting part consisting of superconductor of SQUID magnetometer
The shape of the portion is equal to the shape of the superconducting enclosure,
Forming a superconductor and a superconducting enclosure forming an air detector
The shortest distance of the superconductor is determined by any cross section of the superconductor.
And the outer portion of the magnetic detection unit
A superconductor and a superconductor forming the superconducting enclosure
However, at least the superconductor continuously in the outer portion
A magnetometer characterized in that a part thereof is arranged so as to overlap. 14. The magnetometer according to claim 8, wherein said magnetometer comprises:
The SQUID magnetometer has a structure in which the SQUID ring is divided in parallel.
Direct coupling type SQUID
A magnetometer characterized by the above. 15. The functional superconducting magnetic sheet according to claim 2,
SQUID magnetometer on one side of the superconducting enclosure
A magnetometer characterized in that it is arranged in close contact with the magnet. 16. The functional superconducting magnetic sheet according to claim 7,
SQUID magnetometer on one side of the superconducting enclosure
A magnetometer characterized in that it is arranged in close contact with the magnet. 17. A plurality of magnetometers according to claim 8.
A magnetic measuring device characterized by the above-mentioned. 18. A plurality of magnetometers according to claim 14.
A magnetic measuring device, characterized in that: 19. A plurality of magnetometers according to claim 15.
A magnetic measuring device, characterized in that: 20. A superconductor wound around a columnar body.
A spiral superconductor formed while being advanced in the axial direction of the columnar body.
One end of the conductor and the other end are outside the spiral superconductor
Connected to form a single superconducting closed loop, and a noise magnetic field
Functional superconducting magnetic seal characterized by shielding
De. 21. The functional superconducting magnetic system according to claim 20,
In the field, the structure which divided the SQUID ring in parallel
Having a direct coupling type SQUID magnetometer,
The plane containing the magnetic detection part is set to the axis of the spiral superconductor.
A magnetometer characterized in that one is arranged vertically . 22. The functional superconducting magnetic shield according to claim 25.
In the above, the shape of the cross section perpendicular to the axis of the columnar body is a circle,
Triangle, polygon with at least 4 sides, at least 4
A machine characterized by being one of regular polygons having sides
Superconductive magnetic shield. 23. The functional superconducting magnetic system according to claim 20,
In the field, the structure which divided the SQUID ring in parallel
Having a direct coupling type SQUID magnetometer,
The plane containing the magnetic detection part is set to the axis of the spiral superconductor.
Arrange multiple units vertically and measure magnetism at multiple points simultaneously
A magnetometer characterized by the above. 24. A plurality of magnetometers according to claim 21.
A magnetic measuring device, characterized in that: 25. A plurality of magnetometers according to claim 23.
A magnetic measuring device, characterized in that: