JPH02302681A - Gradiometer - Google Patents

Abstract

PURPOSE:To shorten not only a vacuum drawing time by facilitating degassing but also the cooling time of a magnetic flux input circuit by supporting the superconductor coil of the magnetic flux input circuit by a support member composed of a non-magnetic material high in heat conductivity. CONSTITUTION:The superconductor coil of the magnetic flux input circuit 31 connected to a superconductive quantum interference element 30 is supported by a plurality of support members 35 composed of a non-magnetic material high in heat conductivity and a resin material is used only at the part around which a superconductor coil is wound in a small amount. When the magnetic flux input circuit is brought into contact with the cooler 25 of a freezer A to be directly cooled, since the superconductor coil is supported by the members 35 and the used resin material is little, degassing becomes easy and a vacuum drawing time can be shortened. Since the conduction of heat to the superconductor coil is accelerated by the members 35 high in heat conductivity, the coldness generated in the freezer A is efficiently conducted to the circuit 31 and the cooling efficiency of the circuit 31 is enhanced.

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 Quantum Inter4ere
nce Device) and a magnetic flux input circuit consisting of a superconducting coil connected to the element.

(Prior Art) A superconducting quantum interference element that utilizes the Josephson 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) In this gradiometer, a magnetic flux input circuit is generally formed by winding a superconducting coil around a cylindrical bobbin made of a resin material such as Bakelite. In such a structure, when the gradiometer is immersed in liquid helium and cooled to an extremely low temperature level (the temperature level at which it becomes superconducting), both the superconducting quantum interference element and the superconducting coil, which are the superconducting elements of the gradiometer, are completely immersed in liquid helium. Since it can be cooled directly, there is no problem. However, for example, when the gradiometer is brought into contact with a cooler of a refrigerator such as a helium refrigerator so as to allow heat transfer, and the gradiometer is directly cooled by heat conduction from the refrigerator, the bobbin of the magnetic flux input circuit is made of resin. Since it is a material,
In order to degas the gas, it is necessary to continue evacuation for a long time. Furthermore, since this resin material has a large heat capacity and a low thermal conductivity, there is a problem that the cooling efficiency for the magnetic flux input circuit is low and the cooling time until the superconducting state is reached is long. In particular, when a plurality of superconducting quantum interference devices and magnetic flux input circuits are arranged to form a multichannel system, the above problem becomes even more remarkable.

The present invention has been made in view of the above, and its main purpose is to facilitate degassing and shorten the evacuation time by improving the configuration of the magnetic flux input circuit in the gradiometer. The objective is to shorten the cooling time of the magnetic flux input circuit by reducing the heat capacity and increasing the thermal conductivity.

(Means for Solving the Problems) In order to achieve the above object, the invention according to claim (1) includes a superconducting quantum interference device (30) that becomes a superconducting state at an extremely low temperature level, and a superconducting quantum interference device (30) that becomes a superconducting state at an extremely low temperature level. A magnetic flux input circuit (30) consisting of a superconducting coil (31a) is connected to
1), the superconducting coil (31a) is supported by a plurality of supporting members (35), (35), . . . made of a non-magnetic material with high thermal conductivity.

In addition, in the invention according to claim (2), a plurality of superconducting quantum interference elements (30) and magnetic flux input circuits (31) are arranged, and the plurality of magnetic flux input circuits (31), (31), . . . When the coil (31a) is arranged in parallel in the direction along the plane passing through the coil (31a) to form multiple channels, the support members (35), (35) of one magnetic flux input circuit (31) and the magnetic flux input circuit (31) ) are shared with the supporting members (35), (35) of the magnetic flux input circuit (31) adjacent to the magnetic flux input circuit (31).

Furthermore, in the invention according to claim (3), in order to eliminate the need for a resin material and further improve degassing properties and cooling efficiency, the superconducting coil (31a) is connected to a plurality of supporting members (
35), (35), ... to form a loop shape.

In addition, in the invention according to claim (4), in a structure in which a superconducting coil is wound around an annular bobbin, when an electrically conductive material is used for the bobbin, the bobbin has an eddy current that is harmful to the magnetic flux of the gradiometer. In order to prevent the occurrence of loops, a slit is formed by cutting out a portion of the bobbin, and a non-electrically conductive material is fitted into the slit.

(Function) With the above configuration, in the invention according to claim (1), the superconducting coil (31a) of the gradiometer (B) includes a plurality of support members (35) made of a non-magnetic material with high thermal conductivity,
Since the structure is supported by (35), ..., the amount of resin material can be reduced by using only the part around which the superconducting coil (31a) is wound, and the gradiometer (B)
Even when directly cooling the resin material by bringing it into contact with the cooler (25) of the refrigerator (A) in a heat transfer manner, the resin material can be easily degassed and the evacuation time can be shortened. Moreover, since the support member (35) promotes heat conduction to the superconducting coil (31a), the cold generated in the refrigerator (A) is efficiently transmitted to the magnetic flux input circuit (31), and the magnetic flux The cooling efficiency of the input circuit (31) can be improved and its cooling time can be shortened.

In addition, in the invention according to claim (2+), a gradiometer (
A) multiple magnetic flux input circuits (31), (31),...
・When creating multiple channels by arranging them in parallel in the direction along the plane passing through the superconducting coil (31a), a certain magnetic flux input circuit (
31) and the supporting member (35) of the magnetic flux input circuit (31) adjacent to the magnetic flux input circuit (31).

(35) is shared with the support member (35).
).

By sharing (35), magnetic flux input circuit (31), (31
) can be arranged close to each other, and the packaging density of the magnetic flux input circuit (31) can be increased.

Further, in the invention according to claim (3), since the superconducting coil (31a) is directly wound around the support member (35),
The coil winding eliminates the need for a resin material, and the evacuation time and cooling time can be further shortened.

Furthermore, in the invention according to claim (4), in the structure in which the superconducting coil is wound around the annular bobbin, a non-electrically conductive material is fitted into the slit of the bobbin', so that the bobbin is made of an electrically conductive material. Even if the current is generated by magnetic induction in the bobbin, it is blocked by the non-electrically conductive material of the slit and does not become an eddy current, so that the magnetic flux of the gradiometer can be stably maintained. .

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

In FIG. 1, (A) is a binary circuit helium refrigerator for cooling a gradiometer (B) according to a first embodiment of the present invention. The refrigerator (^) has a vacuum container (1) that is airtightly sealed, the inside of the vacuum container (1) is kept in a vacuum state, and a gradiometer (B) is installed inside this 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 (16).
7) is installed. The pre-cooling refrigeration circuit (2) is composed of a G-M (Gifford-McMahon) cycle refrigerator, which compresses and expands helium gas in order to pre-cool the helium gas in the J-7 circuit (16). Yes, there is a pre-cooling compressor and the above expander (not shown).
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 the low-pressure gas outlet (4b) and a valve motor that drives the rotary valve are fitted. Then, by opening the rotary valve in the expander (3), high pressure helium gas is pumped into the cylinder (13).
Simon is expanded 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). Hold. 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 precooler (22) described later in the J-7 circuit (16) is
), (23) and returns the expanded low pressure helium gas to the compressor for recompression. A closed precooling refrigeration circuit (2) is configured.

On the other hand, the above J-T circuit (16) operates at an extremely low temperature 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 (1B) 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. In addition, at the lower part of the support part (1B), 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 installed.
1) are connected. Each of the above J-T heat exchangers (19)
- (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 member to be inspected (26).
) are in heat transferable contact. In addition, inspected parts (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.

Furthermore, the said cooler (25) is the said 3rd and 21st-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 section (18). 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 stage sinks (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 helium is heated to 1 atm in the cooler (25) and becomes a gas-liquid mixture of about 4.5 m, and the latent heat of vaporization of this helium causes the test member (2B), the test plate (27), and the gradiometer (B) in contact with it to be heated. The helium gas is cooled to an extremely low temperature level (approximately 4K), and then the helium gas, which has become low pressure due to the expansion, is transferred to the first to 37th-T heat exchangers (19).
~ (21) through each secondary side to be sucked into the J-T compressor and recompressed.

The gradiometer (B) has nine superconducting quantum interference elements (30) that become superconducting at extremely low temperatures.

(30), ... and the superconducting quantum interference device (30),
, (30)..., the same number of magnetic flux input circuits (31) connected to each other.

(31), ..., and each magnetic flux input circuit (31) has four superconducting coils (31a), (31a) arranged on the same straight line, as shown in FIG.
, . . . are connected in series so that the current flows in opposite directions.

As a feature of the present invention, as shown in FIGS. 1 and 2, each superconducting coil (31a) constituting the magnetic flux input circuit (31) is wound around a rectangular plate-shaped bobbin (32). . This bobbin (32) is made of Bakelite, etc.
It is made of a non-magnetic and non-electrically conductive material, and has a central hole (33) formed in its center that passes between the upper and lower surfaces. Further, a ring-shaped coil winding part (32a) is formed around the center hole (33) on the lower surface of the bobbin (32), and superconducting coils (3, 1a) are formed around the outer periphery of this coil winding part (32a).
) is wrapped in a loop.

A coil unit (34) is constituted by this bobbin (32) and a superconducting coil (31a) wound around the bobbin (32).

Furthermore, four support columns (35), (35), etc. made of non-magnetic materials with high thermal conductivity such as aluminum and copper are penetrated into the corners of the bobbin (32). The upper end of each support column (35) is fixed to a disc-shaped plate (37), and this plate (37) is attached to the inspection plate (27) of the refrigerator (A) so that heat can be transferred thereto. There is. Therefore, each of the above coil units (34
The superconducting coil (31a) of ) is supported by four pillars (35), (35), . . . made of a non-magnetic material with high thermal conductivity. As shown in FIG. 1, the four coil units (34), (34),...
One of them is at the bottom end of the pillars (35), (35), ..., the other one is in the upper and lower middle of the pillars (35), ((5), ..., and the remaining two are supported by the pillars (35), (35), .

(34), -... superconducting coil (31a), (
31a) and - are connected in series as shown in FIG. 3 to constitute a magnetic flux input circuit (31).

And the above nine magnetic flux input circuits (31), (31)
.

... is for each superconducting coil (3
1a) are arranged in 3 rows and 3 rows in the direction (horizontal direction), and one magnetic flux input circuit (31
) of each coil unit (34).
5), (35) and each coil unit (3) in the magnetic flux input circuit (31) adjacent to the magnetic flux input circuit (31).
It is shared with pillars (35) and (35) in 4).

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 (16) 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 (18), high pressure helium gas discharged from the compressor is supplied to the vacuum container (1) side, and high pressure helium gas supplied to the vacuum container (1) side. is the high pressure gas inlet (18a) of the support part (1B).
) 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 enters the primary side of the second J-T heat exchanger (20), and is similarly heat-exchanged with the low-pressure helium gas on the secondary side.
After being cooled to K, it enters the second precooler (28) 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 portion of the helium in the gas-liquid mixed state, the inspection member (2G) and the inspection plate (
27) is cooled. When this test plate (27) is cooled, the superconducting quantum interference element (3) of the gradiometer (B) which is in contact with the test plate (27) in a heat transferable manner
0) 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 down to about 300K (room temperature) through the secondary side of the compressor. 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 8) falls towards the cryogenic level (operating temperature level) and after reaching the cryogenic level the gradiometer (B) becomes operational.

In this embodiment, the coil unit (34) around which the superconducting coil (31a) of each magnetic flux input circuit (31) in the gradiometer (B) is wound is arranged on four pillars (35).

(35),... are supported by these pillars (35)
, (35).

... is in contact with the inspection plate (27), which is cooled by the cooler (25) of the refrigerator (A), in a heat transferable manner, so the resin material is connected to the bobbin (32) around which the superconducting coil is wound.
The amount of resin material used can be reduced. As a result, even when the gradiometer (B) is cooled with the refrigerator (A), the resin material can be easily degassed, and the refrigerator (
The evacuation time when sucking air from inside the vacuum container (1) before operation A) can be shortened. Furthermore, since each of the above-mentioned pillars (35) is made of a non-magnetic material with high thermal conductivity, the superconducting coil (31a) is
) of the refrigerator (A) is promoted.
The cold generated in step 25) is efficiently transmitted to the magnetic flux input circuit (3I), and therefore the magnetic flux input circuit (31)
It is possible to improve the cooling efficiency and shorten the cooling time.

Additionally, a strut (35) of one flux input circuit (31).

(35) and the pillars (35), (35) of the magnetic flux input circuit (31) adjacent to the magnetic flux input circuit (31) are shared. The magnetic flux input circuits (31), (31) can be placed close to each other, and even in the case of multi-channeling, the magnetic flux input circuits (31), (31).

The packaging density of ... can be increased. In particular, if the area of the circular space surrounded by the superconducting coil (31a) is increased, the sensitivity of the gradiometer (B) can be increased; however, even in this case, the magnetic flux input circuit (31a)
) can reduce the installation space.

In addition, since each of the four superconducting coils (31a), (31a), . or if the size is different,
Accordingly, prepare the required number of coil units (34), combine them according to the purpose, adjust the position and number of the coil units (34), and adjust the coil units (34).
It is only necessary to connect 1a) in series, which greatly reduces the effort.

In addition, since the above-mentioned pillars (35) and bobbin (32) are non-magnetic, there is little magnetic influence when detecting magnetic flux with the gradiometer (B), and even weak magnetic flux can be stably detected. I can do it.

It should be noted that the present invention is not limited to the above embodiments, but includes various other modified embodiments. For example, in the configuration of the above embodiment, a slit is formed by cutting out a part of the bobbin (32) in the coil unit (34) of each magnetic flux input circuit (31), and a non-electrically conductive material is formed in the slit. may be fitted. In that case, even if the bobbin (32) is made of an electrically conductive material, the current generated in the bobbin (32) by magnetic induction is blocked by the non-electrically conductive material of the slit, preventing an eddy current loop. Therefore, the magnetic flux measurement of the gradiometer (B) can be carried out stably.

Further, in the above embodiment, nine magnetic flux input circuits (31),
Although (31), . That is, FIG. 4 shows a second embodiment of the present invention, and the same parts as in FIG. Circuit (31), (31
),... 6-channel gradiometer (B
), and the bobbin (32) has a substantially regular hexagonal shape and has six through holes (33"), (33'),...
32) At equal intervals (60
The windings of each coil are spaced apart from each other (3 intervals).
A superconducting coil (31a) is wound around 2a). Therefore, in this example, multiple flux input circuits (
This is effective when arranging 31), (31), . . . in a circular shape.

FIGS. 5 and 6 show a third embodiment. In this embodiment, in a 5-channel gradiometer (B), the bobbin (32) of each coil unit (34) is of a rectangular plate shape. , five magnetic flux input circuits (31).

(31), ... coil unit (34), (34
), . . . are arranged in a cross shape when viewed from below, and as shown in FIG. 5, the surrounding four magnetic flux input circuits (31),
The pillars (35) of (31), . . . are inclined upwardly away from the pillars (35) of the central magnetic flux input circuit (31). In this way, the magnetic flux input circuit (31), (31).

By arranging..., the magnetic flux input circuit (31),
A substantially hemispherical space is formed below (31a), . . . , and this space can be used as a space for accommodating the head, for example, when measuring magnetic flux associated with human brain waves.

Moreover, FIGS. 7 and 8 show a fourth embodiment, and in this embodiment, four pillars (35), (35), .・These pillars (35), (35),
... four superconducting coils (31a), (31a
), . . . are directly wound around each other to form a rectangular loop. In addition, spacers (1B) made of square plate-shaped Bakelite are provided between the columns (35) and (35) to adjust the distance between the columns (35) and (35).
(3B) is provided.

Therefore, in this embodiment, each magnetic flux input circuit (31)
The superconducting coils (31a) of the columns (35), , (3
5) Since it is wrapped directly around the refrigerator (A
) There are few things intervening between the cooler (25) and each superconducting coil (31a), so the evacuation time and cooling time described above can be further shortened. Furthermore, the superconducting coil (31a) can be tightly wound, which is advantageous in terms of packaging density of the magnetic flux input circuit (31).

Furthermore, FIGS. 9 and 10 show a fifth embodiment, in which nine magnetic flux input circuits (31) are provided.

When forming a 9-channel gradiometer (B) having (31), .
It is wrapped directly around... In the case of this embodiment, in addition to being able to obtain the same effects as in the fourth embodiment, the supporting columns (35) of the adjacent magnetic flux input circuits (31), (31).

(35) are shared with each other, so the magnetic flux input circuit (
The packaging density of 31) can be further increased.

(Effects of the Invention) As explained above, according to the invention according to claim (1), the superconducting coil of the magnetic flux input circuit connected to the superconducting quantum interference element in the gradiometer is made of a non-magnetic material with high thermal conductivity. By supporting the gradiometer with a support member, it is possible to reduce the amount of resin material that requires degassing, has a high heat capacity, and has low thermal conductivity. Even when the gradiometer is cooled by a refrigerator, it is possible to reduce the amount of resin material that needs to be degassed. This makes it possible to easily perform evacuation and shorten the evacuation time, and also to efficiently transmit the cold from the refrigerator to the magnetic flux input circuit, thereby improving the cooling efficiency of the magnetic flux input circuit and shortening the cooling time.

In addition, according to the invention according to claim 2, when a plurality of gradiometers are arranged to have multiple channels, the supporting members of adjacent magnetic flux input circuits are shared, so that the adjacent magnetic flux input circuits are brought close to each other. This arrangement can increase the packaging density of the magnetic flux input circuit, and is particularly effective when increasing the measurement sensitivity by increasing the area within the superconducting coil.

Furthermore, according to the invention according to claim (3), since the superconducting coil is directly wound around the supporting member, no resin material is required for winding the coil, and the evacuation time and cooling time are further reduced. It is possible to shorten the time.

According to the invention according to claim (4), when the superconducting coil is wound around the annular bobbin, a slit is formed in the bobbin and a non-electrically conductive material is fitted therein, so that the bobbin becomes electrically conductive. Even if the bobbin is made of a magnetic material, it is possible to prevent eddy currents from being generated in the bobbin, and the magnetic flux of the gradiometer can be stably maintained at a constant value of 11$1.

[Brief explanation of drawings]

1 to 3 show a first embodiment of the present invention, FIG. 1 is an explanatory diagram schematically showing a refrigerator and a gradiometer, and FIG.
The figure is a schematic plan view of the magnetic flux input circuit, and FIG. 3 is a perspective view showing the schematic structure of the gradiometer. FIG. 4 is a diagram corresponding to FIG. 2 showing the second embodiment. 5 and 6 show the third embodiment, FIG. 5 is a schematic front view of the magnetic flux input circuit, and FIG. 6 is a schematic front view of the magnetic flux input circuit.
The figure is a plan view of the same. 7 and 8 show a fourth embodiment, in which FIG. 7 is a front view of the magnetic flux input circuit, and FIG. 8 is a plan view thereof. 9 and 10 show the fifth embodiment, FIG. 9 is a diagram equivalent to FIG. 7, and FIG. 10 is a diagram equivalent to FIG. 8. (A)... Helium refrigerator (2)... Pre-cooling refrigeration circuit (3)... Expander (14), (15)... Heat station (1
B)...J-7 circuit (24)...J-T valve (25)...Cooler (B)...Gradiometer (30)...Superconducting quantum interference element (31)...・Magnetic flux input circuit (31a)...Superconducting coil (32)...Bobbin (34)...Coil unit (35)...Strut (supporting member) t -°・Patent applicant Daikin Industries, Ltd. □ Agent
Person Patent Attorney Front 1) Hiroshi (2 people) Pa' (A)...
・Helium refrigerator (2)...Precooling refrigeration circuit (3)...Expansion machine (14), (15)...Heat station (18)
)...J-7 circuit (24)...J-T valve (25)...Cooler (B)...Gradiometer (30)...Superconducting quantum interference element (31)... Magnetic flux input circuit (31a)...Superconducting coil (32)...Bobbin (34)...Coil unit (35)...Strut (supporting member)! Fi1 Figure 3 Figure 2 Figure 4 Figure 6 Figure 5! P17 figure Helmet figure 8

Claims (4)

[Claims] (1) A magnetic flux input circuit (
31), the superconducting coil (31a) is supported by a plurality of support members (35), (35), etc. made of a non-magnetic material with high thermal conductivity. Characteristic gradiometer. (2) Superconducting quantum interference device (30) and magnetic flux input circuit (
31) are arranged, and a plurality of magnetic flux input circuits (31),
(31), ... are arranged in parallel in the direction along the plane passing through the superconducting coil (31a), and one magnetic flux input circuit (
The supporting members (35), (35) of 31) and the supporting members (35), (35) of the magnetic flux input circuit (31) adjacent to the magnetic flux input circuit (31) are shared. The gradiometer according to claim (1). (3) The superconducting coil (31a) includes a plurality of supporting members (3
5), (35), . . . to form a loop shape.
2) The gradiometer described. (4) The superconducting coil is wound around an annular bobbin, and the bobbin has a slit formed by cutting out a portion of the bobbin, and a non-electrically conductive material is fitted into the slit. Claim (1) or (2) characterized by
Gradiometer mentioned.