JP2005057076A - Cooling apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling apparatus capable of suppressing noise from intruding to a superconducting element. <P>SOLUTION: The cooling apparatus is provided with a compressor 3 for compressing helium gas, an expander 5 for expanding the helium gas compressed by the compressor 3, and an element mount unit 9 connected to the expander 5 and on which a SQUID as the superconducting element is mounted. The compressor 3 is covered by an apparatus shield 33 comprising an electromagnetic shield case 31 and a magnetic shield case 32, parts of the expander 5 other than a heat generating unit are covered by an apparatus shield 53 comprising an electromagnetic shield case 51 and a magnetic shield case 52, a heatsink 14 provided to the heat generating unit of the expander 5 is covered by a heat sink shield 143 comprising an electromagnetic shield case 141 and a magnetic shield case 142, and a power supply 11 is covered by an electromagnetic shield case 111. Preventing leakage of an electromagnetic wave and a magnetic wave from the power supply 11, the compressor 3 and the expander 5 can reduce noise intruded into an output signal of the SQUID. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cooling device for cooling a superconducting element.

  Conventionally, in order to cool a superconducting element such as a SQUID (Superconducting Quantum Interference Device), for example, a cooling apparatus using a pulse tube refrigerator or the like has been used (see, for example, Patent Document 1). . The pulse tube refrigerator includes a compressor that is driven by an electric motor to generate a pressure pulse of refrigerant, a pulse tube connected to the compressor, and a buffer tank connected to the pulse tube. It is filled with helium gas as a refrigerant. The pressure pulse of helium gas generated by the compressor is sequentially transmitted to the pulse tube and the buffer tank, and the phase of the pressure pulse is converted by the buffer tank, and the end of the pulse tube connected to the buffer tank is Cold occurs in the part. Cold heat is accumulated in the cooling stage provided at the end of the pulse tube to cool the SQUID mounted on the cooling stage.

However, the conventional cooling device has a problem that electromagnetic waves generated during operation of the compressor become noise with respect to the SQUID, and the magnetic field detection sensitivity and accuracy of the magnetometer using the SQUID are reduced.
JP 2002-048423 A

  Therefore, an object of the present invention is to provide a cooling device that can prevent noise with respect to a superconducting element.

In order to achieve the above object, a cooling device of the present invention includes a compressor that compresses a refrigerant,
An expander for expanding the refrigerant;
An element mounting portion connected to the expander and mounted with a superconducting element;
While covering at least one of the said compressor or an expander, it is provided with the apparatus shield which consists of an electromagnetic shielding material and a magnetic shielding material, It is characterized by the above-mentioned.

  According to the above configuration, the refrigerant compressed by the compressor is expanded by the expander, and cold heat is generated in the expander. With this cold heat, the element mounting portion is cooled, and the superconducting element mounted on the element mounting portion is cooled to a predetermined operating temperature. Here, electromagnetic waves and magnetism generated when the compressor operates are prevented from leaking to the outside by an equipment shield covering the compressor. Therefore, electromagnetic waves and magnetism from the compressor are prevented from reaching the superconducting element. As a result, the noise of the superconducting element is reduced. Further, the device shield covering the expander prevents electromagnetic waves and magnetism transmitted from the compressor to the expander from reaching the superconducting element. This prevents noise from the superconducting element.

  The cooling device of one embodiment is characterized in that the equipment shield has a vent hole.

  According to the embodiment, the heat generated during the operation of the compressor is released to the outside of the equipment shield through the vent hole of the equipment shield. Therefore, the disadvantage that the compressor becomes abnormally high is prevented, and the performance of the compressor is stabilized. As a result, the superconducting element mounted on the element mounting portion is stably cooled to a predetermined temperature, the performance of the superconducting element is stabilized, and noise of the superconducting element is prevented.

  Further, heat generated during the operation of the expander is radiated to the outside of the equipment shield through the vent hole of the equipment shield. Therefore, the inconvenience that the expander becomes abnormally high is prevented, and the performance of the expander is stabilized. As a result, cold is stably generated by the expander, and the superconducting element mounted on the element mounting portion connected to the expander is stably cooled to a predetermined temperature. As a result, noise of the superconducting element is prevented.

  A cooling device according to an embodiment is characterized in that the compressor and the expander are connected and a magnetic-shielding connecting pipe made of a magnetic shielding material is provided.

  According to the above embodiment, even if the magnetism of the compressor leaks to the outside, for example, from the refrigerant discharge port of the compressor, the magnetic shield connection pipe is connected to the refrigerant discharge port, thereby Magnetism is prevented from leaking outside the connecting pipe. Therefore, the magnetism is effectively prevented from reaching the superconducting element, and as a result, the noise of the superconducting element is reduced. The magnetic shield connecting pipe may be connected at one end to either the refrigerant discharge port or the refrigerant suction port of the compressor, or connected to a discharge / suction port that performs both refrigerant discharge and suction. Also good. Correspondingly, the other end of the magnetic shield connecting pipe may be connected to either the refrigerant suction port or the refrigerant discharge port of the expander, and suction / discharge for both the suction and discharge of the refrigerant. You may connect to the outlet.

  The cooling device of one embodiment is characterized in that the magnetic shield connecting pipe is covered with an electromagnetic shield made of an electromagnetic shielding material.

  According to the embodiment, even if the electromagnetic wave of the compressor leaks from the refrigerant discharge port to the outside of the compressor, for example, the magnetic shield connection pipe covered with the electromagnetic shield is provided at the refrigerant discharge port. By connecting, the electromagnetic wave is prevented from leaking to the outside. Therefore, the electromagnetic wave is effectively prevented from reaching the superconducting element, and as a result, noise of the superconducting element is prevented.

The cooling device of one embodiment includes a connecting pipe that connects the compressor and the expander;
The connection pipe is covered, and a connection pipe shield made of an electromagnetic shielding material and a magnetic shielding material is provided.

  According to the embodiment, even when electromagnetic waves and magnetism generated by the compressor leak outside from the refrigerant discharge port of the compressor, for example, the refrigerant discharge port is covered with the connecting pipe shield. By connecting the broken connection pipe, the electromagnetic wave and magnetism are prevented from leaking to the outside. Therefore, electromagnetic waves and magnetism from the compressor are effectively prevented from reaching the superconducting element, and as a result, noise of the superconducting element is prevented.

The cooling device of one embodiment includes a power source for supplying power to the compressor,
In addition to covering the power supply, a power supply shield made of an electromagnetic shielding material and a magnetic shielding material is provided.

  According to the embodiment, the power shield prevents electromagnetic waves and magnetism from the power source from leaking outside the power shield. Therefore, electromagnetic waves and magnetism from the power source are effectively prevented from reaching the superconducting element, and as a result, noise of the superconducting element is prevented.

  The cooling device of one embodiment is characterized in that the power shield is thermally connected to a casing that houses the compressor, an expander, and a power source.

  According to the embodiment, the heat generated by the power source is transmitted to the casing via the power shield and released to the outside of the casing. Therefore, the heat generated by the power source is prevented from being accumulated in the cooling device, and the refrigerating capacity is prevented from being lowered. As a result, the superconducting element mounted on the element mounting portion can operate stably, and noise of the superconducting element is prevented.

  Here, “thermally connecting” means connecting so that heat conduction is possible.

  A cooling device according to an embodiment is characterized in that a casing that houses the compressor, the expander, and the power source is formed of an electromagnetic shielding material and a magnetic shielding material.

  According to the embodiment, since the casing is formed of an electromagnetic shielding material and a magnetic shielding material, electromagnetic waves and magnetism generated by the compressor, the expander, and the power source may leak out of the casing. Is prevented. Therefore, the electromagnetic waves and magnetism are effectively prevented from reaching the superconducting element located outside the casing, and as a result, noise of the superconducting element is effectively prevented.

  A cooling device according to an embodiment includes an electromagnetic shielding material and a magnetic shielding material, and includes a vacuum vessel that covers the periphery of the superconducting element and the element mounting portion and whose pressure is reduced.

  According to the embodiment, since the decompression container is composed of an electromagnetic shielding material and a magnetic shielding material, electromagnetic waves and magnetism are effectively prevented from entering the decompression container. Therefore, the superconducting element in the decompression vessel is effectively prevented from noise caused by electromagnetic waves and magnetism.

A cooling device according to an embodiment includes a cooling fan that cools at least one of the compressor and the expander;
The motor for driving the cooling fan is covered and a motor shield made of a magnetic shielding material is provided.

  According to the embodiment, since the compressor and the expander are cooled by the cooling fan, the refrigeration performance of the cooling device becomes stable. Therefore, since the superconducting element is stably frozen at a predetermined temperature, the performance of the superconducting element is stabilized and the noise of the superconducting element is reduced. The motor shield prevents the motor magnetism from leaking outside. Therefore, magnetism from the motor to the superconducting element is prevented, and as a result, noise of the superconducting element is prevented.

  The motor shield may be formed of an electromagnetic shielding material instead of the magnetic shielding material, or may be formed of a magnetic shielding material and an electromagnetic shielding material. Thereby, the electromagnetic waves from the motor are prevented from reaching the superconducting element, and noise of the superconducting element is prevented.

  The cooling device of one embodiment is located below the element mounting part and the superconducting element, and closes the vicinity of the lower end of the cylindrical part, covering the upper part and the side of the element mounting part and the superconducting element. An element casing formed of an electromagnetic shielding material and a magnetic shielding material, having a lid, and a signal line extraction portion that is formed between the cylindrical portion and the lid and from which a signal line connected to the superconducting element is extracted. It is characterized by having.

  According to the above embodiment, the cylindrical portion and the lid portion of the element casing are made of the electromagnetic shielding material and the magnetic shielding material, so that electromagnetic waves and magnetism are prevented from entering the element casing. Therefore, the superconducting element effectively prevents noise caused by electromagnetic waves and magnetism. Further, by forming the signal line take-out portion in a sleeve shape, electromagnetic waves and magnetism can be effectively prevented from entering the element casing.

  Thus, the cooling device of the present invention includes a compressor that compresses the refrigerant, an expander that expands the refrigerant, an element mounting portion that is connected to the expander and on which a superconducting element is mounted, and the compression Since the apparatus shield includes at least one of the machine and the expander and includes an apparatus shield made of an electromagnetic shielding material and a magnetic shielding material, it is possible that electromagnetic waves and magnetism from the compressor and the expander reach the superconducting element. This can be prevented by the shield, and as a result, noise of this superconducting element can be prevented.

  In the cooling device according to one embodiment, since the equipment shield has a vent hole, heat generated during operation of the compressor and the expander can be radiated to the outside through the vent hole of the equipment shield. And the inconvenience that the expander becomes abnormally hot. Therefore, the performance of the compressor and the expander can be stabilized, the superconducting element can be stably cooled to a predetermined temperature, and the performance of the superconducting element can be stabilized. As a result, the noise of the superconducting element can be stabilized. Can be prevented.

  The cooling device according to an embodiment connects the compressor and the expander, and includes a magnetic-shielding connection pipe made of a magnetic shielding material, so that even if the magnetism from the compressor leaks to the outside from, for example, a refrigerant discharge port, By connecting the magnetic shield connecting pipe to the refrigerant discharge port, the magnetism can be prevented from leaking to the outside. Therefore, it is possible to effectively prevent the superconducting element from being magnetized, and as a result, it is possible to prevent noise of the superconducting element.

  In the cooling device of one embodiment, since the magnetic shield connecting pipe is covered with an electromagnetic shield made of an electromagnetic shielding material, even if the electromagnetic wave generated by the compressor leaks to the outside from, for example, the refrigerant discharge port, By connecting the magnetic shielding connecting pipe covered with the electromagnetic shield to the refrigerant discharge port, it is possible to prevent electromagnetic waves from leaking to the outside of the electromagnetic shield. Therefore, electromagnetic waves can be effectively prevented from reaching the superconducting element, and as a result, noise of the superconducting element can be prevented.

  A cooling device according to an embodiment includes a connection pipe that connects the compressor and the expander, and a connection pipe shield that covers the connection pipe and includes an electromagnetic shielding material and a magnetic shielding material. Even when the electromagnetic wave and magnetism leaked to the outside from, for example, the refrigerant discharge port of the compressor, by connecting the connection pipe covered with the connection pipe shield to the refrigerant discharge port, Electromagnetic waves and magnetism can be prevented from leaking outside. Therefore, electromagnetic waves and magnetism can be effectively prevented from reaching the superconducting element, and as a result, noise of the superconducting element can be prevented.

  The cooling device according to an embodiment includes a power source that supplies power to the compressor and a power shield that covers the power source and includes an electromagnetic shielding material and a magnetic shielding material. Can be prevented from leaking. Therefore, electromagnetic waves and magnetism can be effectively prevented from reaching the superconducting element, and as a result, noise of the superconducting element can be prevented.

  In the cooling device according to an embodiment, the power shield is thermally connected to a casing that houses the compressor, the expander, and the power source. Therefore, heat generated by the power source is transmitted through the power shield. Can be transmitted to the casing and discharged to the outside of the casing. Therefore, it is possible to effectively prevent a decrease in the refrigerating capacity due to the heat generated by the power source, and to stably hold the superconducting element at a predetermined temperature.As a result, the superconducting element can be stably operated, The noise of this superconducting element can be reduced.

  In the cooling device of one embodiment, since the casing that houses the compressor, the expander, and the power source is formed of an electromagnetic shielding material and a magnetic shielding material, electromagnetic waves and magnetism can be prevented from leaking out of the casing. Therefore, the electromagnetic waves and magnetism can be effectively prevented from reaching the superconducting element located outside the casing, and as a result, noise of the superconducting element can be effectively prevented.

  The cooling device according to one embodiment includes an electromagnetic shielding material and a magnetic shielding material, and includes a vacuum container that covers the periphery of the cooling unit on which the superconducting element is mounted and whose inside is decompressed. It can prevent effectively entering the inside of a container. Therefore, it is possible to effectively prevent noise caused by electromagnetic waves and magnetism in the superconducting element in the decompression vessel.

  A cooling device according to an embodiment includes a cooling fan that cools at least one of the compressor or the expander, a motor that drives the cooling fan, and a motor shield that includes an electromagnetic shielding material and a magnetic shielding material. By cooling the compressor and the expander with the cooling fan, the refrigeration performance of the cooling device can be stabilized and the superconducting element can be stably frozen at a predetermined temperature. Therefore, the performance of the superconducting element can be stabilized and noise of the superconducting element can be prevented. Further, the motor shield can prevent electromagnetic waves and magnetism from the motor driving the cooling fan from leaking to the outside, and as a result, the electromagnetic waves and magnetism can be prevented from reaching the superconducting element. The noise of the element can be prevented.

  The cooling device of one embodiment is located below the element mounting part and the superconducting element, and closes the vicinity of the lower end of the cylindrical part, covering the upper part and the side of the element mounting part and the superconducting element. An element casing formed of an electromagnetic shielding material and a magnetic shielding material, having a lid, and a signal line extraction portion that is formed between the cylindrical portion and the lid and from which a signal line connected to the superconducting element is extracted. Therefore, electromagnetic waves and magnetism can be prevented from entering the element casing. Therefore, generation of noise due to electromagnetic waves and magnetism can be effectively prevented for the superconducting element.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

  FIG. 1 is a schematic cross-sectional view showing a cooling device according to a first embodiment of the present invention. The cooling device 1 includes a compressor 3 that compresses helium gas as a refrigerant, an expander 5 that expands the helium gas compressed by the compressor 3, and an element mounting portion 9 that is connected to the expander 5. Have In this element mounting portion 9, a SQUID (Superconducting Quantum Interference Device) as a superconducting element is mounted. The compressor 3 includes a discharge / suction port for discharging and suctioning refrigerant, and one end of a connection pipe 13 is connected to the discharge / suction port. The other end of the connection pipe 13 is connected to one end of the expander 5. One end of the expander 5 is a heat generating part that rises in temperature during operation, and a heat radiating plate 14 for discharging the heat of the heat generating part to the outside of the expander 5 is provided. The other end of the expander 5 is a cooling unit 7 that cools down during operation, and the element mounting unit 9 is connected to the cooling unit 7. A power source 11 for supplying power to the compressor 3 is disposed on the opposite side of the compressor 3 from the side on which the expander 5 is disposed. The compressor 3, the connecting pipe 13, the heat radiating plate 14, and the power source 11 are accommodated in a casing 23. The casing 23 is provided with a cooling fan 16 and a drive motor 18, and the drive motor 18 drives the cooling fan 16 to blow air into the casing 23 to cool the inside of the casing 23. On the other hand, the expander 5, the element mounting portion 9 and the SQUID are housed in a vacuum container 25 whose inside is decompressed.

  The compressor 3 is covered with a device shield 33 including an electromagnetic shielding case 31 as an electromagnetic shielding material and a magnetic shielding case 32 as a magnetic shielding material. Further, the portion of the expander 5 other than the portion provided with the heat dissipation plate 14 is covered with a device shield 53 including an electromagnetic shielding case 51 as an electromagnetic shielding material and a magnetic shielding case 52 as a magnetic shielding material. . Further, the heat radiating plate 14 is covered with a heat radiating plate shield 143 including an electromagnetic shielding case 141 as an electromagnetic shielding material and a magnetic shielding case 142 as a magnetic shielding material. The heat sink shield 143 covers one end of the inflator 5 together with the heat sink 14 and functions as a device shield. The power source 11 is covered with an electromagnetic shielding case 111 as an electromagnetic shielding material.

  Each electromagnetic shielding case is made of a high permeability material such as permalloy and mu metal, and each electromagnetic shielding case is made of high-purity aluminum, aluminum alloy, high-purity copper and copper alloy (for example, brass), etc. It is made of a material having high electrical conductivity. FIG. 1 schematically shows the cooling device of the present embodiment. The electromagnetic shielding case and the magnetic shielding case may be formed in close contact with each other, or may be formed with a gap therebetween. Good.

  When the cooling device 1 having the above-described configuration is operated, electric power is supplied from the power source 11 to the compressor 3, and a pulsed pressure fluctuation of helium gas is generated by the compression unit driven by the motor in the compressor 3. . The pulsed helium gas that changes in pressure is supplied to the expander 5 through the connecting pipe 13, and one end of the expander 5 is heated and the other is cooled. And cold heat is accumulate | stored in the element mounting part 9 connected to the other end of the said expander 5, and SQUID mounted in this element mounting part 9 is cooled to cryogenic temperature.

  When the cooling device 1 operates, electromagnetic waves are generated from the power source 11 and the motor of the compressor 3. However, since the power source 11 is covered with the electromagnetic shielding case 111 and the compressor 3 is covered with the device shield 33, electromagnetic waves are prevented from leaking out from the power source and the compressor 3. Therefore, electromagnetic waves from the power source 11 and the compressor 3 are effectively prevented from reaching the SQUID. As a result, it is possible to effectively prevent noise from occurring in the output signal of the SQUID.

  Further, even when the electromagnetic wave generated by the compressor 3 is transmitted to the expander 5 through the connecting pipe, the heat sink 14 of the heat generating part of the expander 5 is covered with the heat sink shield 143. At the same time, since the expander 5 is covered with the equipment shield 53, electromagnetic waves are prevented from leaking out of the expander 5. Therefore, electromagnetic waves from the expander 5 are effectively prevented from reaching the SQUID. As a result, it is possible to effectively prevent noise from occurring in the output signal of the SQUID.

  Further, a magnetic field is generated by the motor of the compressor 3, and when the compressor 3 is driven, the magnetic field strength of the motor varies. However, since the compressor 3 is covered with the equipment shield 33, the magnetism of the compressor 3 is prevented from leaking outside. Therefore, the magnetism of the compressor 3 is effectively prevented from reaching the SQUID. As a result, it is possible to effectively prevent noise from occurring in the output signal of the SQUID. Even when the magnetism is transmitted from the compressor 3 to the expander 5 through the connecting pipe 13, the heat dissipation plate 14 of the heat generating portion of the expander 5 is covered with the heat dissipation plate shield 143, and the above Since the expander 5 is covered with the device shield 53, the magnetism is prevented from leaking out of the expander 5. Therefore, the magnetism from the expander 5 is effectively prevented from reaching the SQUID. As a result, it is possible to effectively prevent noise from occurring in the output signal of the SQUID.

  Further, one end of the compressor 3, the power source 11 and the expander 5 generates heat with the operation of the cooling device. However, since the casing 23 that houses them is blown from the outside by the cooling fan 16, the heat generated in the heat generating portions of the compressor 3, the power source 11 and the expander 5 is cooled through an exhaust port (not shown). Released to the outside of the device 1. Therefore, the compressor 3, the power source 11, and the expander 5 are prevented from reaching an abnormally high temperature, and the refrigeration capacity of the cooling device is stably maintained. As a result, the SQUID is stably cooled to a predetermined temperature and the performance is stabilized, so that it is possible to effectively prevent noise from being generated in the output signal of the SQUID.

  The cooling fan 16 may cool any one of the compressor 3, the expander 5, the power supply 11, and the heat radiating plate 14.

  Further, the device shields 33 and 53 may be provided in only one of the compressor 3 and the expander 5. The heat sink shield 143 may not be provided.

  Further, the power supply 11 is provided with only the electromagnetic shielding case 111 as an electromagnetic shielding material, but a magnetic shielding material may be further provided.

  FIG. 2A is a schematic front view showing a modification of the device shield 33 covering the compressor 3 and the heat sink shield 143 covering the heat sink 14. FIG. 2B is a schematic side view showing only the device shield 33 of the compressor 3. Both the device shield 33 and the heat sink shield 143 are provided with a plurality of vent holes 20 and 21. The vent holes 20 and 21 are formed in a substantially uniform density on substantially the entire surface of the device shield 33 and the heat sink shield 143. The device shield 33 and the heat radiating plate shield 143 allow air to pass through the vent holes 20 and 21, so that the heat radiation efficiency of the compressor 3 in the device shield 33 is improved and the heat radiation in the heat radiating plate shield 143 is also improved. The heat dissipation efficiency of the plate 14 is improved. Therefore, it is possible to effectively prevent the compressor 3 and the expander 5 from becoming abnormally high temperature during the operation of the cooling device 1, and to effectively stabilize the cooling capacity of the cooling device 1.

  FIGS. 3A and 3B are cross-sectional views showing modifications of the connecting pipe 13 that connects the compressor 3 and the expander 5.

  The connecting pipe 131 shown in FIG. 3A is made of a high permeability material as a magnetic shielding material, and forms a magnetic shielding connecting pipe. That is, even if magnetism is transmitted from the compressor 3 through the discharge / suction port into the connecting pipe 131, the connecting pipe 131 is made of a high magnetic permeability material, so that the transmitted magnetism hardly leaks to the outside. Therefore, the magnetism from the compressor 3 is effectively prevented from reaching the SQUID. As a result, it is possible to effectively prevent noise from occurring in the output signal of the SQUID.

  The connection pipe 133 shown in FIG. 3B has an electromagnetic shield 132 made of a high electrical conductivity material as an electromagnetic shielding material on the surface of a magnetic-shielding connection pipe 131 made of a high permeability material similar to that shown in FIG. Provided. The connecting pipe 133 can prevent leakage of magnetism to the outside by the magnetic shield connecting pipe 131, and can prevent leakage of electromagnetic waves to the outside by the electromagnetic shield 132. Accordingly, it is possible to effectively prevent the magnetism and electromagnetic waves from the compressor 3 from reaching the SQUID through the discharge / suction port of the compressor 3. As a result, it is possible to effectively prevent noise from occurring in the output signal of the SQUID.

  The connection pipe 133 in FIG. 3B is formed of the magnetic shield connection pipe 131 and the magnetic shield 132 to prevent leakage of magnetism and electromagnetic waves. However, the connection pipe 133 in FIG. A connecting pipe shield made of a magnetic shielding material may be provided to prevent leakage of electromagnetic waves and magnetism.

  FIG. 4 is a schematic cross-sectional view showing the cooling device of the second embodiment. In this cooling device, the power source 11 is covered with a power shield 113 including an electromagnetic shielding case 111 as an electromagnetic shielding material and a magnetic shielding case 112 as a magnetic shielding material, and the power shielding 113 is thermally applied to the casing 23. Connected. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the cooling device of the second embodiment, since the power source 11 is covered with the power shield 113, it is possible to effectively prevent electromagnetic waves and magnetism generated by the power source 11 from leaking to the outside of the power shield 113. Therefore, the electromagnetic waves and magnetism from the power supply 11 are prevented from reaching the SQUID, and it is possible to effectively prevent noise from occurring in the output of the SQUID.

  Further, since the power shield 113 is thermally connected to the casing 23, the heat generated by the power source 11 is efficiently transmitted to the casing 23 via the power shield 113, and the outside of the casing 23. Can be released efficiently. Therefore, the power supply 11 is prevented from becoming abnormally high temperature, and the performance of the cooling device is stabilized. Therefore, the SQUID can be stably cooled to a predetermined temperature to stabilize the performance, and output noise can be reduced.

  FIG. 5 is a schematic cross-sectional view showing the cooling device of the third embodiment. In this cooling device, a casing 232 that accommodates the compressor 3, the connecting pipe 13, the heat sink 14, and the power source 11 is formed by an electromagnetic shielding casing 231 as an electromagnetic shielding material and a magnetic shielding casing 232 as a magnetic shielding material. ing. In the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the cooling device of the third embodiment, the casing 232 is formed by the electromagnetic shielding casing 231 and the magnetic shielding casing 232, so that electromagnetic waves and magnetism generated by the compressor 3 and the power source 11 leak to the outside of the casing 232. It can be effectively prevented. Therefore, electromagnetic waves and magnetism from the compressor 3 and the power source 11 are effectively prevented from reaching the SQUID located outside the casing 232. As a result, it is possible to effectively prevent noise from occurring in the detection signal of the SQUID.

  In the embodiment, the casing 232 may be thermally connected to the power source 11 or a casing that houses the power source 11.

  FIG. 6 is a schematic cross-sectional view showing the cooling device of the fourth embodiment. In this cooling device, a driving motor 18 of a cooling fan 16 provided in a casing 23 that houses a compressor 3, a connecting pipe 13, a heat radiating plate 14, and a power source 11 is covered with a motor shield 181 made of a magnetic shielding material. In the fourth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the cooling device of the fourth embodiment, the drive motor 18 of the cooling fan 16 is covered with the motor shield 181 made of a magnetic shielding material, so that the magnetism of the drive motor 18 is prevented from leaking outside. Therefore, the magnetism from the drive motor 18 to the SQUID is prevented, and as a result, it is possible to effectively prevent the inconvenience that noise occurs in the detection signal of the SQUID.

  The motor shield 181 may be formed of an electromagnetic shielding material instead of the magnetic shielding material, or may be formed of a magnetic shielding material and an electromagnetic shielding material. Thereby, also about the electromagnetic waves from the said drive motor 18, the arrival amount to the said SQUID can be reduced and the noise of the output signal of the said SQUID can be reduced.

  FIG. 7 is a schematic cross-sectional view showing the cooling device of the fifth embodiment. In this cooling device, a portion other than the heat generating portion of the expander 5 and a vacuum vessel 253 that accommodates the element mounting portion 9 and the SQUID and whose pressure is reduced is formed of an electromagnetic shielding material and a magnetic shielding material. In the fifth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the cooling device of the fifth embodiment, since the vacuum vessel 253 is formed of an electromagnetic shielding material and a magnetic shielding material, electromagnetic waves and magnetism can be effectively prevented from entering the vacuum vessel 253. Therefore, electromagnetic waves and magnetism can be effectively prevented from reaching the SQUID in the vacuum vessel 253, and the noise of the SQUID can be effectively reduced.

  FIG. 8 is a schematic cross-sectional view showing the cooling device of the sixth embodiment. In this cooling device, the element mounting portion 9 and the SQUID mounted on the element mounting portion 9 are covered with an element casing 26 made of an electromagnetic shielding material and a time shielding material. In the sixth embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The element casing 26 included in the cooling device of the present embodiment is located below the element mounting portion 9 and the SQUID, and a cylindrical portion 27 that covers the upper side and the side of the element mounting portion 9 and the SQUID. And a lid portion 28 that closes the vicinity of the lower end. The lid portion 28 includes a disc portion having a smaller diameter than the cylindrical portion 27 and a sleeve-like portion that extends to the edge of the disc portion and extends downward. A signal line extraction portion 29 for extracting the SQUID signal line 91 is formed by a gap between the lower end portion of the cylindrical portion 27 and the sleeve-shaped portion of the lid portion 28. Since the signal line extraction portion 29 is formed in a sleeve shape, it is difficult for electromagnetic waves and magnetism to enter from outside via the signal line extraction portion 29. Further, since the cylindrical portion 27 and the lid portion 28 of the element casing 26 are formed of an electromagnetic shielding material and a time shielding material, electromagnetic waves and magnetism can be prevented from entering the element casing 26. Therefore, electromagnetic waves and magnetism can be effectively prevented from reaching the SQUID in the element casing 26, and as a result, the noise of the output signal of the SQUID can be effectively reduced.

  In the above-described embodiment, the signal line extraction portion 29 may be a gap formed over the entire circumferential direction between the lower end of the cylindrical portion 27 and the lower end of the lid portion 28. It may be a gap formed in a part of the direction.

  FIG. 9A is a schematic front view showing a further modification of the device shield 33 covering the compressor 3. The device shield 33 is provided with the vent hole 20 at both end portions in the axial direction on the side surface of the device shield 33 having a substantially cylindrical shape, while the vent hole 20 is not provided near the central portion in the axial direction. Further, the vent holes 20 are not provided on both end surfaces of the device shield 33. FIG. 9B is a front view schematically showing lines of magnetic force generated in the compressor 3 accommodated in the equipment shield 33. In the compressor 3 having a substantially cylindrical shape, as indicated by an arrow A in FIG. 9B, the magnetic field lines are emitted in the radial direction from the center in the axial direction of the side surface and are directed in the axial direction on both end surfaces. Incident. Therefore, the vent hole 20 is provided only at both end portions in the axial direction of the device shield 33. In other words, the ventilation hole 20 is not provided in the vicinity of the central portion of the side surface of the device shield 33 and the both end surfaces, thereby reliably reducing the passage of magnetic lines of force and effectively preventing leakage of the lines of magnetic force from the device shield 33. It is preventing. Further, a ventilation hole 20 is provided in a portion where the magnetic lines of force do not pass, so that the heat dissipation of the compressor 3 is effectively performed. Therefore, prevention of magnetic leakage of the compressor 3 and cooling can be effectively made compatible, and the influence of magnetism on the SQUID can be reduced and the cooling temperature of the SQUID can be stabilized. As a result, the noise of the output signal of the SQUID can be effectively reduced.

  The device shield 33 is provided with the vent holes 20 at both end portions in the axial direction on the side surface. However, the portion provided with the vent holes 20 may be changed as appropriate in the lines of magnetic force generated in the compressor accommodated by the device shield. Can do. That is, in the equipment shield, a vent hole may be provided in a portion where the magnetic field lines generated by the compressor hardly pass.

  Moreover, although the vent hole 20 was not provided in the part which the magnetic force line of the compressor 3 passes in the said apparatus shield 33, you may provide a vent hole with a diameter smaller than the vent hole provided in another part.

  Further, the electromagnetic shielding case 31 and the magnetic shielding case 32 that form the device shield 33 may be formed with a gap therebetween or in close contact with each other. In order to improve the heat dissipation efficiency of the device shield 33, it is preferable that the device shields 33 be formed in close contact with each other.

  FIG. 10 is a schematic cross-sectional view showing the device shield 33. As shown in FIG. 10, a gap 34 is provided between the end surface of the compressor 3 and the inner surface of the equipment shield 30. Air is allowed to pass through the gap 34 from the end surface to the side surface of the compressor 3. As a result, the heat generated on the end face of the compressor 3 can be transferred to the equipment shield via the gap 34 without providing the vent hole 20 in the part of the equipment shield 30 facing the end face of the compressor 3. The air is efficiently discharged from the vent holes 20 on the 30 side surfaces. As a result, the compressor 3 can be efficiently cooled while maintaining the magnetic leakage prevention function of the device shield.

  In each of the above-described embodiments, the compressor 3 discharges and sucks the refrigerant through the discharge / suction port. However, the compressor 3 may be provided with a discharge port and a suction port separately. In this case, a discharge pipe may be connected to the discharge port, a suction pipe may be connected to the suction port, and a magnetic shield connection pipe may be used for each pipe. Moreover, you may provide an electromagnetic shield in the said magnetic-shielding connection pipe.

  In each of the above embodiments, the electromagnetic shielding cases 31, 51, 141, and 111 are used as electromagnetic shielding materials. However, the electromagnetic shielding material is not limited to a case as long as it exhibits an electromagnetic shielding action. Those having other forms may be used. Also, the magnetic shielding material is not limited to the case, and a material having another form such as a thin film or fiber may be used as long as it exhibits a magnetic shielding action.

  Although the cooling device of each said embodiment was formed using the pulse tube refrigerator, other refrigerators, such as a Stirling refrigerator and GM (Gifford McMahon) refrigerator, can also be used. In short, the cooling method is not limited as long as a cooling device that cools the superconducting element to the operating temperature of the superconducting element can be configured.

  Moreover, although the cooling device of each said embodiment cools SQUID as a superconducting element, it may cool another superconducting element.

It is a schematic sectional drawing which shows the cooling device of 1st Embodiment of this invention. Fig.2 (a) is a schematic front view which shows the modification of the apparatus shield of a compressor, and a heat sink shield. FIG.2 (b) is a schematic side view which shows the modification of an apparatus shield. 3 (a) and 3 (b) are cross-sectional views showing modifications of the connecting pipe that connects the compressor and the expander. It is a schematic sectional drawing which shows the cooling device of 2nd Embodiment. It is a schematic sectional drawing which shows the cooling device of 3rd Embodiment. It is a schematic sectional drawing which shows the cooling device of 4th Embodiment. It is a schematic sectional drawing which shows the cooling device of 5th Embodiment. It is a schematic sectional drawing which shows the cooling device of 6th Embodiment. Fig.9 (a) is the schematic front view which showed the further modification of the apparatus shield of a compressor. FIG. 9B is a front view schematically showing lines of magnetic force generated in the compressor housed in the equipment shield. It is a schematic sectional drawing which shows an apparatus shield.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cooling device 3 Compressor 5 Inflator 7 Cooling part 9 Element mounting part 11 Power supply 13 Connection pipe 14 Heat sink 16 Cooling fan 18 Drive motor 23 Casing 25 Depressurization container 31 Electromagnetic shielding case 32 Magnetic shielding case 33 Equipment shielding 51 Electromagnetic shielding case 52 Magnetic shielding case 53 Equipment shield 111 Electromagnetic shielding case 141 Electromagnetic shielding case 142 Magnetic shielding case 143 Heat sink shield

Claims (11)

A compressor (3) for compressing the refrigerant;
An expander (5) for expanding the refrigerant;
An element mounting portion (9) connected to the expander (5) and mounted with a superconducting element;
A device shield (33, 53, 143) that covers at least one of the compressor (3) or the expander (5) and is composed of an electromagnetic shielding material (31, 51, 141) and a magnetic shielding material (32, 52, 142). And a cooling device. The cooling device according to claim 1, wherein
The said apparatus shield (33,143) has a vent hole (20,21), The cooling device characterized by the above-mentioned. The cooling device according to claim 1 or 2,
A cooling device characterized in that the compressor (3) and the expander (5) are connected and a magnetic-shielding connecting pipe (131) made of a magnetic shielding material is provided. The cooling device according to claim 3, wherein
The said magnetic-shielding connection pipe | tube (131) is covered with the electromagnetic shield (132) which consists of electromagnetic shielding materials, The cooling device characterized by the above-mentioned. The cooling device according to claim 1 or 2,
A connecting pipe (13) connecting the compressor (3) and the expander (5);
A cooling device comprising a connecting pipe shield made of an electromagnetic shielding material and a magnetic shielding material while covering the connecting pipe (13). The cooling device according to any one of claims 1 to 5,
A power supply (11) for supplying power to the compressor;
A cooling device comprising a power shield (113) made of an electromagnetic shielding material (111) and a magnetic shielding material (112) while covering the power source (11). The cooling device according to claim 6, wherein
The cooling device, wherein the power shield (113) is thermally connected to a casing (23) that houses the compressor (3), the expander (5), and the power source (11). The cooling device according to any one of claims 1 to 7,
The cooling apparatus characterized by forming the casing which accommodates the said compressor (3), an expander (5), and a power supply (11) with the electromagnetic shielding material (231) and the magnetic shielding material (232). The cooling device according to any one of claims 1 to 8,
A cooling device comprising a vacuum vessel comprising an electromagnetic shielding material (251) and a magnetic shielding material (252) and covering the periphery of the superconducting element and the element mounting portion (9) and the inside of which is decompressed. The cooling device according to any one of claims 1 to 9,
A cooling fan (16) for cooling at least one of the compressor (3) or the expander (5);
A cooling device comprising: a motor shield (181) made of a magnetic shielding material while covering a motor (18) for driving the cooling fan (16). The cooling device according to any one of claims 1 to 10,
A cylinder part (27) covering the upper and sides of the element mounting part (9) and the superconducting element, and a lower end of the cylinder part (27) located below the element mounting part (9) and the superconducting element A lid portion (28) that closes the vicinity, and a signal line extraction portion that is formed between the cylindrical portion (27) and the lid portion (28) and from which the signal line (91) connected to the superconducting element is extracted. (29) and an element casing (26) made of an electromagnetic shielding material and a magnetic shielding material.

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