JP2679491B2 - Superconducting magnetic detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic detecting device provided with a superconducting quantum interference device (abbreviated as SQUID hereinafter).

[0002]

2. Description of the Related Art FIG. 3 is a diagram showing a conventional superconducting magnetism detecting device. In the figure, 1 is a block whose SQUID can be fixed, 2 is an X-axis SQUID, 3 is a Y-axis SQ
UID, 4 is a Z-axis SQUID, 5 is a heat insulating container having a double cylindrical structure, 6 is a supporting rod for supporting the above block,
Reference numeral 7 is a vacuum heat insulating portion between the outer wall and the inner wall of the heat insulating container, 8 is a coolant such as liquid helium for cooling the SQUID to an operating temperature, and 9 is a wiring for extracting a signal from the X-axis SQUID 2 to the outside. X-axis wiring board for connecting to the Y-axis wiring board for connecting to the wiring for extracting the signal from the Y-axis SQUID3 to the outside, and 11 for wiring the signal from the Z-axis SQUID4 to the outside. Is a Z-axis wiring substrate for connecting to S., and 12 is a wiring for extracting a signal from the SQUID to the outside.

The conventional superconducting magnetism detecting device is constructed as described above. For example, the block 1 is a rectangular parallelepiped made of ceramics, glass or the like, and the X-axis SQUIDs 2 are provided on the mutually orthogonal planes of the block 1. Y-axis SQUID3, Z-axis SQUID4 and each SQUI
An X-axis wiring board 9, a Y-axis wiring board 10, and a Z-axis wiring board 11 which are wiring boards corresponding to the ID are fixed. The block 1 is supported by a support rod 6 and has a vacuum heat insulating portion 7 so that it can be immersed in a refrigerant 8 such as liquid helium stored inside a cylinder inside a heat insulating container 5 having a heat insulating effect. X placed and fixed to the block
Axis SQUID2, Y axis SQUID3, Z axis SQUID4
Are cooled to about the same temperature as the refrigerant. X-axis SQU
The magnetic fields detected by the ID2, the Y-axis SQUID3, and the Z-axis SQUID4 are taken out as electric signals from the wiring 12 via the X-axis wiring board 9, the Y-axis wiring board 10, and the Z-axis wiring board 11, respectively. X-axis SQUID2 and X-axis wiring board 9, Y-axis SQUID3 and Y-axis wiring board 10, Z
The axis SQUID 4 and the Z-axis wiring board 11 are electrically connected to each other, for example, by wire-bonding a platinum wire or the like.
The 0, Z-axis wiring board 11 is electrically connected to the wiring 12 by, for example, soldering. The electrical signal taken out by the wiring 12 is sent to a signal processing device (not shown) or the like to be processed and the change in the measured magnetic field is detected.

[0004]

The conventional device as described above has the following problems. That is, as the wiring board, a material such as a glass reinforced epoxy board which is generally used by printing a pattern is used. on the other hand,
As the block, a patterned SQUID is bonded and fixed on a silicon crystal, and it has to withstand a temperature cycle from room temperature to an operating temperature of SQUID, which is a liquid helium temperature. Used. As a result, due to the difference in heat shrinkage between the SQUID and the block, peeling may occur at the bonding surface between the SQUID and the block, or the block may be destroyed. Similarly, due to the difference in heat shrinkage between the wiring board and the block, the adhesive surface between the wiring board and the block may be peeled off or the block may be destroyed.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a superconducting detector capable of withstanding a thermal cycle from room temperature to the operating temperature of SQUID.

[0006]

A superconducting magnetism detecting device according to the present invention comprises a block and a wiring board made of a material having a heat shrinkage ratio close to that of SQUID.

[0007]

In the superconducting magnetism detecting device configured as described above, the amount of heat shrinkage that occurs between the room temperature of the SQUID and the operating temperature of the SQUID or the temperature of the refrigerant depends on the room temperature of the block and the operating temperature of the SQUID or the refrigerant. Amount of heat shrinkage up to temperature, room temperature of wiring board and SQUID
It is almost equal to the amount of heat shrinkage that occurs up to the operating temperature or the temperature of the refrigerant. So SQUID and block,
The stress generated by thermal contraction can be reduced at the joints between the block and the wiring board, and as a result, the SQUID and the block and the joint surface between the block and the wiring board can be peeled off or damaged. Do not wake up.

[0008]

【Example】

Embodiment 1 FIG. FIG. 1 is a diagram showing an embodiment of the present invention,
Reference numerals 2 to 8 and 12 in the figure are exactly the same as those of the conventional device. 1 is aluminum nitride (AI) as an example of the material.
It is a block using ceramics whose main component is N). Reference numerals 9, 10, and 11 are an X-axis wiring board, a Y-axis wiring board, and a Z-axis wiring board, which use ceramics containing aluminum nitride (AIN) as a main component, respectively, as an example of the material. The heat shrinkage ratio, which indicates the shrinkage ratio from the basic size of the base material between the room temperature of the silicon crystal that is the main material of SQUID and the temperature of the SQUID operating temperature or the temperature of the refrigerant, is 5 × 10 5.
^{-5 to} 6 × 10 ^-4 , block and X-axis wiring board, Y
Aluminum nitride (A
IN) as the main component of ceramics from room temperature to SQUI
D Heat yield up to operating temperature or refrigerant temperature is 1
It is from x10 ^{-4 to} 7x10 ^-4 . Therefore, the SQUID
Since the difference in the amount of heat shrinkage between the bonding surface and the block, and the wiring board and the block is small, quartz glass is used as the material of the block as in the prior art, and glass-reinforced epoxy is used as the wiring board. As compared with the above case, the thermal stress generated in the joint is small, and as a result, the problems such as peeling and breakage, which are seen in the prior art, do not occur on any of the joint surfaces.

Although the ceramic of which the main component is aluminum nitride (AIN) is used as the material of the block in the first embodiment, the present invention is not limited to this, and is a main material having a heat shrinkage of SQUID. Those having a thermal contraction rate close to that of a silicon crystal from room temperature to the SQUID operating temperature or the temperature of the refrigerant, for example, ceramics containing silicon nitride (Si ₃ N ₄ ) as a main component, and silicon carbide (SiC) as a main component Ceramics, composite ceramics containing aluminum nitride (AIN) and boron nitride (BN) as main components may be used.

Similarly, although ceramics containing aluminum nitride (AIN) as a main component was used as the material of the wiring board, the present invention is not limited to this, and the thermal contraction rate is SQUI.
A material having a thermal contraction rate close to that of the silicon crystal, which is the main material of D, from room temperature to the SQUID operating temperature or the temperature of the coolant, and a material capable of being metallized that can be used as a wiring board, for example, silicon nitride (Si ₃ N Ceramics containing ₄ ) as a main component may also be used.

Embodiment 2 FIG. FIG. 2 is a diagram showing a second embodiment of the present invention, in which 2 to 8 and 12 are exactly the same as the above conventional device. Reference numeral 1 is a block made of ceramics containing silicon nitride (Si ₃ N ₄ ) as a main component, which can be used as a wiring board and can be metallized, as an example of the material. Reference numeral 13 is a pattern wiring which is directly metallized in one block. The heat shrinkage ratio of the silicon crystal, which is the main material of SQUID, from room temperature to the SQUID operating temperature or the temperature of the refrigerant is 5 × 10 ^{−5 to} 6 × 10 ^−4.
And the thermal contraction rate of ceramics mainly composed of silicon nitride (Si ₃ N ₄ ) as a block material from room temperature to the SQUID operating temperature or the temperature of the refrigerant is 1 × 10 5.
^{-4 to} 7 × 10 ^-4 . Therefore, since the difference in the amount of heat shrinkage at the joint between the SQUID and the block is small,
Compared to the case of using quartz glass as the material of the block as in the prior art, the thermal stress generated in the joint is small, and as a result, the problems such as peeling and breakage at the joint surface are observed in the prior art. No points will be produced.

Further, since there is no joint surface between the wiring board and the block as compared with the prior art, problems such as peeling and destruction at the joint surface between the wiring board and the block, which are seen in the prior art, do not occur.

In the second embodiment, ceramics containing silicon nitride (Si ₃ N ₄ ) as a main component was used as the material of the block, but the present invention is not limited to this, and the thermal shrinkage is mainly SQUID. A material having a thermal contraction rate close to the SQUID operating temperature or the temperature of the coolant of silicon crystal, which is a material, and a material which can be used as a wiring board and which can be metallized, for example, aluminum nitride (AIN)
Ceramics containing as a main component may be used.

[0014]

As described above, according to the present invention, the superconducting magnetism detecting device is highly reliable because no peeling or damage occurs at the bonding surface between the SQUID and the block or the wiring board and the block. Can be configured.

[Brief description of the drawings]

FIG. 1 is a sectional view showing Embodiment 1 of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

FIG. 3 is a sectional view showing a conventional superconducting magnetism detecting device.

[Explanation of symbols]

1 block, 2 X-axis SQUID, 3 Y-axis SQUID
D, 4 Z axis SQUID, 5 heat insulation container, 6 support rods,
7 Vacuum heat insulation part , 8 Refrigerant, 9 X-axis wiring board, 10
Y-axis wiring board, 11 Z-axis wiring board, 12 wiring, 13
Pattern wiring.

Claims (2)

(57) [Claims] 1. A heat insulating container having a double structure, a superconducting quantum interference device capable of detecting magnetism, and the superconducting quantum interference device fixed on at least two surfaces orthogonal to each other and installed inside the heat insulating container. In a superconducting magnetic detection device having a block and a wiring substrate mounted on the block, ceramics having a thermal shrinkage close to that of the superconducting quantum interference device are used as a material of the block and the wiring substrate. Superconducting magnetic detector. 2. A heat insulating container having a double structure, a superconducting quantum interference device capable of detecting magnetism, and the superconducting quantum interference device fixed to at least two surfaces orthogonal to each other and installed inside the heat insulating container. In the superconducting magnetism detecting device having a block, a ceramic having a thermal shrinkage close to that of the superconducting quantum interference device is used as a material of the block, and the block is directly wired. Magnetic detection device.