JPH02302682A - Gradiometer - Google Patents

Abstract

PURPOSE:To dispense with a circuit fitted to magnetic flux and to obtain the sensitivity fitted to a measuring purpose only by regulating the position of coil units and the number of said units by forming a magnetic flux input circuit 31 as units at every superconductor coils and combining the coil units. CONSTITUTION:A superconductive quantum interference element becoming a superconductive state at an extremely low temp. level and the magnetic flux input circuit 31 connected thereto and composed of superconductor coils 31a are mounted. A plurality of coil units 36 wherein the coils 31a are wound by bobbins 32 are provided and combined to constitute the circuit 31 as a whole. When the kind and size of magnetic flux are different, the units 36 are prepared by a necessary number corresponding thereto to be combined corresponding to a purpose and the arranging positions of the units 36 or the use number of them is regulated to connect the coils 31a in series in reverse directions.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is directed to a superconducting quantum interference device (S Q U I D ;
ductlve Quantus Interfere
The present invention relates to an improvement of a gradiometer equipped with a magnetic flux input circuit consisting of a superconducting coil connected to the gradiometer and a superconducting coil connected to the gradiometer.

(Prior Art) A superconducting quantum interference element that utilizes the Dicefson effect has been known as one of the superconducting devices. By connecting a magnetic flux input circuit consisting of a superconducting coil to this superconducting quantum interference element, it is possible to obtain a gradiometer that can measure extremely weak magnetic flux, such as the magnetism associated with minute currents flowing within a living body. .

(Problems to be solved by the invention) By the way, 1. This gradiometer can measure very weak magnetic flux, which is at a much lower level than the earth's magnetism, so it is attracting attention as being effective in a variety of applications, such as diagnosing the human heart and lungs, and measuring brain waves. However, when the type and size of the target magnetic flux differs, it is necessary to change the magnetic flux input circuit used each time, and it is necessary to prepare a large number of magnetic flux input circuits with optimal sensitivity depending on the purpose of measurement. However, there was a problem in that it took a lot of effort.

The present invention has been made in view of the above, and its main purpose is to improve the configuration of the magnetic flux input circuit in a gradiometer, thereby eliminating the trouble of preparing magnetic flux input circuits individually depending on the purpose of measurement. It's about trying to reduce it.

(Means for Solving the Problem) In order to achieve the above object, in the invention according to claim (1), the superconducting coils that are the constituent elements of the magnetic flux input circuit are unitized with the same configuration, and by combining the units, the entire Configure a magnetic flux input circuit.

That is, as shown in FIGS. 1 to 3, a superconducting quantum interference device (30) that becomes superconducting at an extremely low temperature level, and a superconducting coil (31a) connected to the superconducting quantum interference device (30) In a gradiometer equipped with a magnetic flux input circuit (31), a plurality of coil units (38) are provided in which the superconducting coil (31a) is wound around a bobbin (32), and the plurality of coil units (38), (38) are provided.
),... to create the superconducting coil (31a)
, (31a), . . . constitute the magnetic flux input circuit (31).

Further, in the invention according to claim (2), for example, the gradiometer is connected to a cooler (25) of a refrigerator (A) such as a helium refrigerator.
) in such a way that the refrigerator (A) is directly cooled to an extremely low temperature level (a temperature level at which a superconducting state occurs), the cooling efficiency is increased, and the transmission from the refrigerator (A) is increased. In order to facilitate cooling by heat, the coil unit (36) is supported by a support member (31) made of a non-magnetic material with high thermal conductivity.

Furthermore, in the invention according to claim (3), in order to facilitate the sensitivity setting of the gradiometer, as shown in FIG. 11, the plurality of coil units (38), (3)
8), superconducting coil (31a) in...
(31a) The pitch between , . . . can be adjusted.

(Function) With the above configuration, in the invention according to claim (1), a plurality of coil units (38) each having a superconducting coil (31a) wound around a bobbin (32) are provided, and each of the coil units (38) is Since the magnetic flux input circuit (31) is configured by the combination, even if the type or magnitude of magnetic flux is different, the coil unit (ae) can be adjusted accordingly.

(38), . . . can be simply adjusted in the arrangement position and the number of them used, and the effort can be reduced.

Further, in the invention according to claim (2), the coil unit (
38) is a support member (
Since the gradiometer is supported by the support member (31), even when the gradiometer is directly cooled by bringing it into contact with the cooler (25) of the refrigerator (A) in a heat transferable manner, for example, the gradiometer is supported by the support member (31).
) promotes heat conduction, and the cold generated in the refrigerator (A) is efficiently transferred to the magnetic flux input circuit (31), increasing the cooling efficiency for the magnetic flux input circuit (31), and the magnetic flux input circuit (31) Cooling by the refrigerator (A) can be facilitated.

Furthermore, in the invention according to claim (3), the superconducting coil (
Since the pitch between the coils (31a), (31a), ... is adjustable, the coils (31a), (31a), (
31a) The sensitivity of the gradiometer can be easily adjusted to the optimum sensitivity by changing the pitch between .

(Example) Embodiments of the present invention will be described below based on the drawings.

In FIG. 4, (A) is a binary circuit helium refrigerator for cooling the gradiometer (B) according to the first embodiment of the present invention. The refrigerator (A) has a vacuum container (1) that is hermetically sealed, the inside of the vacuum container (1) is kept in a vacuum state, and a gradiometer (B) is installed inside the container (1). is accommodated.

In addition, the vacuum container (1) includes an expander (3) of the pre-cooling refrigeration circuit (2) and an expansion unit (1) of the J-7 circuit (1B).
7) is installed. The pre-cooling refrigeration circuit (2) is composed of a GM (Gifford McMahon) cycle refrigerator, and compresses and expands helium gas in order to pre-cool the helium gas in the J-7 circuit (16). A pre-cooling compressor (not shown) and the expander (3) are connected in a closed circuit.

The expander (3) is attached to the vacuum container (1) in a vibration-insulated manner. This expander (3) is
A casing (4) placed on the outer upper surface of the vacuum container (1)
) and a two-stage cylinder (13) connected to the lower part of the casing (4), and the casing (4) has a high-pressure gas inlet ( 4
a) and a low pressure gas outlet (4b) connected to the suction side. Further, the cylinder (13) penetrates the earth wall of the vacuum container (1) and hangs down inside the container (1), and the lower end of its large diameter part (13a) has a temperature level of 55 to 60 degrees. The first heat station (14
), and a second heat station (15) which is maintained at a temperature level of 15 to 20 degrees lower than that of the first heat station (14) is formed at the lower end of the small diameter portion (13b).

Although not shown here, the cylinder (13)
A displacer is reciprocatably fitted inside the cylinder (13) to define expansion chambers at positions corresponding to the heat stations (14) and (15). On the other hand, inside the casing (4), a valve is opened every time the casing rotates to supply helium gas flowing from the high-pressure gas inlet (4a) to the expansion chamber in the cylinder (13), or to supply helium gas expanded in the expansion chamber. A rotary valve that switches to discharge gas from a low-pressure gas outlet (4b) and a valve motor that drives the rotary valve are fitted. Then, high-pressure helium gas is pumped into the cylinder (13) by opening the low-pressure valve in the expander (3).
Simon expands in the expansion chamber inside the cylinder, and the temperature drop associated with the expansion generates cryogenic cold, which is then transferred to the first and second heat stations (14) and (15) in the cylinder (13). and hold it. Therefore, the high pressure helium gas discharged from the pre-cooling compressor is transferred to the expander (
3), and the temperature of the heat stations (14) and (15) is lowered by adiabatic expansion in the expander (3), and the temperature of the precooler (2) described later in the J-7 circuit (1B) is lowered.
A closed precooling refrigeration circuit (2) is configured to precool the gases 2) and (23) and return the expanded low-pressure helium gas to the compressor for recompression.

On the other hand, the above J-T circuit (1B) has a cryogenic level (approximately 4
K) A refrigeration circuit that compresses helium gas and expands it by Joule-Thomson in order to generate cold air. The expansion unit (17) for Thomson expansion is provided. This expansion unit (17) has a support part (18) arranged on the outer upper surface of the vacuum container (1), and the support part (18) is connected to the discharge side of the J-T compressor. High pressure gas inlet (
18a) and a low pressure gas outlet (18a) connected to the same suction side.
b) is open. Further, at the lower part of the support part (18), first to third J-T heat exchangers (19) to (2) penetrating the earthen wall of the vacuum container (1) and hanging down into the container (1) are provided.
1) are connected. Each of the above J-T rhombic heat exchangers 9)
- (21) are for exchanging heat between the helium gases passing through the primary side and the secondary side, respectively, and the primary side of the first J-T heat exchanger (19) is connected to the high pressure of the support part (18). It is connected to the gas inlet (18a). Further, the primary sides of the first and second J-T heat exchangers (19) and (20) are connected to the first heat station (
14) The first precooler (2
2). Similarly, the second and third J
-The primary sides of the T heat exchangers (20) and (21) are
The second heat station (15) of the expander (3) is connected via a second precooler (23) consisting of a heat exchanger disposed around the outer periphery of the second heat station (15). Furthermore, the third J-T heat exchanger (2
The primary side of 1) is connected to a cooler (25) via a J-T valve (24) that expands high-pressure helium gas.
It is connected to the. The opening degree of the J-T valve (24) is adjusted from outside the vacuum vessel (1) by an operating rod (not shown). In addition, the cooler (25) is a cylindrical test member (2B).
) consists of a coil-shaped pipe wound along the outer periphery of the cooler (25) and the test member (2B).
) are in heat transferable contact. In addition, the cooling member (26)
A testing plate (27) is integrally formed at the lower end of the test plate (27), and the gradiometer (B) is integrally attached to the lower surface of the plate (27) so as to allow heat transfer.

Further, the cooler (25) is connected to the third and second J-T.
1J via each secondary side of heat exchanger (21) and (2G)
- Connected to the secondary side of the T heat exchanger (19), and the first J-
The secondary side of the T heat exchanger (19) is connected to the low pressure gas outlet (18b) of the support part (1B). Therefore, J-
In the first circuit (1B), helium gas is compressed to high pressure by a J-T compressor and supplied to the vacuum vessel (1) side, and is then transferred to the first to third J-T heat exchangers of the vacuum vessel (1). Vessel (19)
In ~(21), heat is exchanged with the low-temperature, low-pressure helium gas that returns to the compressor side, and the first and second precoolers (2
After being cooled by heat exchange with the first and second heat stations (14) and (15) of the expander (3) in 2) and (23), respectively, it is expanded by Joule-Thomson in the J-T valve (24). The cooler (25) generates helium in a gas-liquid mixture state at 1 atm and about 4:00, and the latent heat of vaporization of this helium causes the test member (26), the test plate (27), and the gradiometer (B) in contact with it to become polarized. Low temperature level (about 4K
), and then the helium gas, which has become low pressure due to the expansion, is passed through the first to third J-T heat exchangers (19) to (
21) is configured to be sucked into the J-T compressor through each secondary side and recompressed.

As shown in Figure 3, the gradiometer (B) consists of a superconducting quantum interference element (3) that becomes superconducting at an extremely low temperature level.
0) and a magnetic flux input circuit (31) connected to the superconducting quantum interference element (30), the magnetic flux input circuit (31) comprises two superconducting coils (31a) arranged on the same straight line. ) and (31a) are connected in series so that currents flow in opposite directions to each other.

As a feature of the present invention, as shown in FIG. 1 and FIG. ), (32).

These bobbins (32), (32) have the same structure and are made of non-magnetic and non-electrically conductive material such as Bakelite, with a central hole (33) formed through the center and a coil wound around the outer periphery. A groove (34) is formed, and a superconducting coil (31a) is wound in a loop around this coil winding groove (34). Moreover, the outer peripheral edge of the bobbin (32) has three boss parts (32a), (32a),
... are formed at equal angular intervals (120'' intervals), and each boss portion (32a) is formed with a column insertion hole (35) extending in the direction of the center line of the bobbin (32).

A coil unit (38) is constituted by this bobbin (32) and a superconducting coil (31a) wound around the bobbin (32).

Furthermore, the pillars (31) as supporting members made of a non-magnetic material with high thermal conductivity, such as aluminum or copper, are inserted and fixed into the pillar insertion holes (35).
31), (31), ... are assumed to have the same length,
Its upper end (lower end in Figure 1) is a circular play)
(44), and this plate (44) is attached to the testing brake (27) of the refrigerator (A) via a superconducting quantum interference element (30) so that heat can be transferred thereto. As shown in FIG. 1, one of the two coil units (38), (38) is placed on the lower end of the support (31), and the other is placed on the upper side of the support (31) (inspection plate (2)).
7) side) and are supported at a predetermined pitch from the one coil unit (38).

On the other hand, both the above coil units (36), (38) (
7) The superconducting coils (31a) and <31a) are connected to each other at a terminal box (38). That is, this terminal box (38) has the first to fourth terminals.
The first terminal (38a) is provided with four terminals (38a) to (38d), and one end of the superconducting coil (31a) of the coil winding groove (38) located on the lower side is connected to the second terminal (38a). (38b) has the same coil (31a
) are connected to each other. Further, one end of the superconducting coil (31a) of the upper coil unit (36) is connected to the third terminal (38c), and one end of the superconducting coil (31a) of the upper coil unit (36) is connected to the fourth terminal (38c).
The other end of the coil (31a) is connected to d). And the above-mentioned 1st and 4th terminals (38a
), (38d) are connected to the superconducting quantum interference device (30), while the second and third terminals (38b)
, (38c) are connected to each other, and the magnetic flux input circuit ( 31) is configured. From the above, the magnetic flux input circuit (31) consists of two coil units (3 [i), (38
) is constructed by connecting superconducting coils (31a) and (31a).

Next, the operation of the above embodiment will be explained.

The gradiometer (
Once B) is cooled and the temperature of the gradiometer (B) drops to cryogenic levels (approximately 4K), the gradiometer (B) becomes operational.

That is, first, the compressors of the pre-cooling refrigeration circuit (2) and the J-7 circuit (lB) are started, and the helium refrigerator (A) is activated.
When the is in steady operation, the high pressure helium gas supplied from the precooling compressor expands in the expander (3) in the precooling refrigeration circuit (2), and the temperature drop accompanying the expansion of this gas causes the cylinder (13) to cool down. 1st heat station (14)
is cooled to a temperature level of 55-60°C, and the second heat station (15) to a temperature level of 15-20°C.

On the other hand, at the same time, in the J-7 circuit (16), the high pressure helium gas discharged from the compressor is supplied to the vacuum container (1) side, and the high pressure helium gas supplied to the vacuum container (1) side is the high pressure gas inlet (18a) of the support part (18).
) enters the primary side of the first J-T heat exchanger (19), where it exchanges heat with the low-pressure helium gas on the secondary side that returns to the compressor side and is cooled from room temperature 300K to approximately 70K, and then the expansion The first precooler (22
) and cooled to about 55K. This cooled gas is transferred to the primary side of the second J-T heat exchanger (20), and is similarly heated by heat exchange with the low pressure helium gas on the secondary side.
After being cooled to K, it enters the second precooler (23) on the outer periphery of the second heat station (15), which is cooled to 15-20K in the expander (3), and is cooled to about 15K.

Furthermore, the gas enters the primary side of the third J-T heat exchanger (21) and undergoes heat exchange with the low pressure helium gas on the secondary side.
It is cooled down to K and then reaches the J-T valve (24). In this J-T valve (24), the high-pressure helium gas is throttled and expanded by Joule-Thomson, becoming helium in a gas-liquid mixture state of 1 atm and approximately 400 ml. ). And this cooler (25)
, due to the latent heat of vaporization of the liquid part of the helium in the gas-liquid mixed state, the inspection member (2B) and the inspection plate (
27) is cooled. When this testing plate (27) is cooled down, the superconducting quantum interference element (
30) and the magnetic flux input circuit (31) are also cooled.

Then, the evaporated low-pressure helium gas is transferred to a cooler (25
) returns to the secondary side of the third J-T heat exchanger (21), during which time it becomes a saturated gas of about 4 ml, and this helium gas flows into the second and first J-T heat exchangers (20), (19). The high-pressure helium gas on the primary side is sequentially cooled through the secondary side of the compressor, and the temperature is finally raised to approximately 300K (room temperature). Return to the suction side. The above completes the pre-cooling refrigeration circuit (2) and J-
One cycle of the seven circuits (16) is completed, and thereafter, similar cycles are repeated to perform the refrigeration operation of the refrigerator (A). Due to the continuation of such refrigeration operation, the gradiometer (
The temperature of B) falls towards a cryogenic level (operating temperature level), after reaching which cryogenic level the gradiometer (B) becomes operational.

In the case of this embodiment, the two superconducting coils (31a), (31a) constituting the magnetic flux input circuit (31) are each wound around a bobbin (32) to form a unit, so the type and size of the magnetic flux If it is different, it,
Prepare the required number of coil units (38) according to the purpose, combine them according to the purpose, and adjust the position and number of coil units (36) to use to create the coil (31a).
) in series in the opposite direction, which greatly reduces the effort involved. In particular, in this embodiment, since the coil (31a) is connected through the terminal box (38), the preparation of the magnetic flux input circuit (31) becomes even easier.

Further, each of the coil units (38) has three pillars (31), (31) made of a non-magnetic material with high thermal conductivity.

As mentioned above, the gradiometer (B) is connected to the cooler (A) of the helium refrigerator (A).
Even when cooling is performed directly by the cooler (25), the cooler (25)
) can be efficiently transmitted to the magnetic flux input circuit (31) (superconducting coil (31a)).

As a result, the cooling efficiency for the magnetic flux input circuit (31) increases, making it easier to cool it, and furthermore, the superconducting quantum interference element (30) or the magnetic flux input circuit (31) of the gradiometer (B) reaches a superconducting state. It is possible to shorten the cooling time until

In addition, since the above-mentioned pillars (31) and bobbin (32) are non-magnetic, there is less influence of magnetism when detecting magnetic flux with the gradiometer (B), and even weak magnetic flux can be stably detected. I can do it.

In addition, in the above embodiment, two coil units (38),
(38) (Superconducting coil (31a), (31a
) ) are arranged in parallel with a first-order differential gradiometer (B
), but in addition to this, for example, when using a second-order differential type, four of the above-mentioned coil units (36) are prepared,
Two of them are placed close to each other in the center, and the remaining two are placed away from the center and support columns (31) and (31), respectively.

... and those superconducting coils (31a),
(31a), . . . may be connected using a terminal box.

5 and 6 show a second embodiment (the same parts as in FIGS. 1 and 2 are given the same reference numerals and detailed explanation thereof is omitted), a coil unit (38), Bobbin (32) for winding the superconducting coil (31a)
The shape of the .

That is, the bobbin (32) in this embodiment includes a rectangular plate-shaped support plate (32b) and the support plate (32b).
A disc-shaped coil winding part (3'2c) integrally formed on the lower surface (upper side in FIG. 1) of 2b) is rounded and
2) is formed with a center hole (33) passing through between the support plate (32b) and the coil winding part (32c). Pillar insertion holes (35), (35), ... are formed in the corners of the support plate (32b), and a coil winding groove (34) is formed in the outer periphery of the coil winding part (32c). has been done.

On the other hand, a screw is formed on the outer periphery of each column (31), and as shown in FIG.
5), and insert the support (31) into the bobbin (32).
The nut (39), (39
), the coil unit (38) is connected and supported by the pillars (31), (31), . . . . The rest of the structure is the same as that of the above embodiment.

Therefore, this embodiment can also provide the same effects as the first embodiment. In addition to this,
By loosening the nuts (39) and (39), you can freely adjust the positions of both coil units (38) and (3G).
There is an advantage that the pitch between the two superconducting coils (31a), (31a) can be arbitrarily selected, and the sensitivity of the gradiometer (B) can be easily adjusted to the optimum sensitivity.

FIGS. 7 to 10 show a third embodiment, which is compatible with multi-channel design. In this embodiment, as shown in FIGS. 9 and 10, the support plate (32b) of the bobbin (32) in the coil unit (38) is a stacked stack of two rectangular plates shifted diagonally. shape, and a pillar insertion hole (35) is provided at the corner in the shifting direction.
(35) is formed.

As shown in FIGS. 7 and 8, a large number of bobbins (32), (32), . . . are arranged flush by alternately fitting the shifted portions of the support plate (32b) ,
By inserting the common support (31) into the support plate insertion holes (35), (35) that match at the corners of (32b) and clamping them with the nuts (39), ($9), Coil units (38), (36),...
(Superconducting coil (31a).

(31a),...) are arranged in multiple channels.

Therefore, in the case of this embodiment, the superconducting coil (31a
) and the bobbin (32) around which it is wound, all the coil units (3G) are the same, and a number of coil units (38) are installed on the support post (3G) depending on the purpose of total #1.
By supporting 1), (31), . . . , it is possible to easily achieve multi-channel magnetic flux measurement.

Furthermore, FIG. 11 shows a fourth embodiment, in which the pitch between two superconducting coils ($1a) and (31a) can be variably adjusted from the outside of the vacuum vessel (1), that is, from the room temperature part.

That is, among the pair of coil units (36) and (38) around which the superconducting coil (31a) is wound, the lower coil unit (38) is connected to each support column (31) by a nut (
39).

It is fixedly supported at (39) so as not to be movable. On the other hand, the upper coil unit (36) has its bobbin (3
The pillars (31) are movably inserted into the respective pillar insertion holes (35) of 2), and the bobbin (32)
) is formed with a gear accommodating portion (40) around a predetermined column insertion hole (35),
Inside the gear accommodating portion (40) is a driven gear (41) screwed onto the column (31) passing through the column insertion hole (35), and a gear accommodating portion that is always meshed with the driven gear (41). (40
) is housed in the drive gear (42) rotatably supported by the drive gear (42). The rotation shaft (43) of the drive gear (42) extends upward parallel to the support column (31), and its upper end is connected to the plate (
44) rotatably located above the outside of the vacuum container (1), and by rotating this rotating shaft (43) from outside the container (1), it is driven via the drive gear (42). The gear (41) is screwed on the pillar (31), and this screw movement raises and lowers the upper coil unit (38) to change the pitch between both superconducting coils (31a) and (31a). ing. Note that the length of the rotating shaft (43) changes as the upper coil unit (36) moves up and down. In order to absorb this, a coil spring-like expansion/contraction absorption part (43a) is formed at the upper end of the rotation shaft (43), and this expansion/contraction absorption part (43a) allows the rotation shaft (43) to
It is designed to absorb changes in length.

Therefore, in this embodiment, by rotationally driving the rotating shaft (43), the position of the upper coil unit (36) can be freely adjusted, and the superconducting coils (31a), (31a
), the pitch between gradiometers (B) can be selected arbitrarily.
The sensitivity can be adjusted to the optimum sensitivity very easily. Furthermore, since the rotating shaft (43) can be driven at room temperature outside the container (1), there is an advantage that it can be freely adjusted even while the gradiometer (B) is in operation.

(Effects of the Invention) As explained above, according to the invention according to claim (1), the magnetic flux input circuit connected to the superconducting quantum interference element in the gradiometer is unitized for each superconducting coil, and the coil unit with the same configuration is By combining these blocks to form a magnetic flux input circuit, even if the type or size of the magnetic flux to be measured differs, there is no need to prepare separate magnetic flux input circuits, and the superconducting coil All you have to do is adjust the placement position and the number of pieces used, which can greatly reduce the effort involved.

Further, according to the invention according to claim (2), since the coil unit is supported by a support member made of a non-magnetic material with high thermal conductivity, even when the gradiometer is directly cooled by a refrigerator, the magnetic flux is The cooling efficiency for the input circuit can be increased, and the magnetic flux input circuit can be easily cooled by a refrigerator or the like.

Furthermore, according to the invention according to claim (3), by making the pitch between the superconducting coils adjustable, the sensitivity of the gradiometer can be easily adjusted to the optimum sensitivity.

[Brief explanation of the drawing]

Figures 1 to 4 show a first embodiment of the present invention, in which Figure 1 is a front view showing the connection structure of the coil unit and the connection state of the superconducting coil, Figure 2 is a plan view of the same, and Figure 3 is the same top view. The figure is a perspective view showing the general structure of the gradiometer, and FIG. 4 is an explanatory view schematically showing the main parts of the refrigerator. 5 and 6 show the second embodiment, with FIG. 5 being a diagram corresponding to FIG. 1, and FIG. 6 being a diagram corresponding to FIG. 2. Figures 7 to 10 show the third embodiment, where Figure 7 is a view equivalent to Figure 1, Figure 8 is a view equivalent to Figure 2, Figure 9 is a front view of the superconducting coil, and Figure 10 is the same. FIG. FIG. 11 is a diagram corresponding to FIG. 1 showing the fourth embodiment. (A)... Helium refrigerator (2)... Pre-cooling refrigeration circuit (3)... Expander (14), (15)... Heat station (t
a)...J-T circuit (24)...J-T valve (25)...Cooler (B)...Gradiometer (30)...Superconducting quantum interference element (31)...・Magnetic flux input circuit (31a)...Superconducting coil (32)...Bobbin (36)...Coil unit (31)...Strut (supporting member) (38)...Terminal box Fig. 3 4 figures mostly 5 figures 6 figures 4! ! ll! Figure 7 Figure 8 Figure 9 Figure 10

Claims (3)

[Claims] (1) A magnetic flux input circuit (
31), a plurality of coil units (38) are provided in which the superconducting coil (31a) is wound around a bobbin (32), and the plurality of coil units (36), (36),... A gradiometer characterized in that the magnetic flux input circuit (31) is configured by combining the superconducting coils (31a), (31a), . . . (2) The gradiometer according to claim 1, wherein the coil unit (38) is supported by a support member (31) made of a non-magnetic material with high thermal conductivity. (3) Multiple coil units (36), (36),...
Claim (1) characterized in that the pitch between the superconducting coils (31a), (31a), ... is adjustable.
Or the gradiometer described in (2).