CN107062672B

CN107062672B - Superconducting receiving front-end partition refrigeration structure and implementation method thereof

Info

Publication number: CN107062672B
Application number: CN201710118379.XA
Authority: CN
Inventors: 孙文娟; 陆勤龙; 宾峰; 杨时红; 阮晓明; 郑婷; 刘洋
Original assignee: China Electronics Technology Group Corp No 16 Institute
Current assignee: China Electronics Technology Group Corp No 16 Institute
Priority date: 2017-03-01
Filing date: 2017-03-01
Publication date: 2022-06-21
Anticipated expiration: 2037-03-01
Also published as: CN107062672A

Abstract

The invention relates to a superconducting receiving front-end partition refrigeration structure and an implementation method thereof. The refrigeration structure comprises a cylinder, a primary cold head arranged at the top of the cylinder, a primary cold plate arranged above the primary cold head, a metal ring sleeved on the outer side of the middle section of the cylinder and tightly matched with the cylinder, and a secondary cold plate connected with the outer side wall of the metal ring through a supporting cold head; the metal ring comprises a first metal ring part and a second metal ring part which are coaxial and are sequentially arranged from inside to outside; the material of the first metal ring part is the same as that of the cylinder; the material of the second metal ring part is the same as that of the support cold head and the secondary cold plate. The invention can solve the defects in the prior art, and can carry out partition refrigeration on different devices in the Dewar, so that the devices such as a superconducting filter, a switch and the like can normally work, and a lower system noise coefficient index can be obtained.

Description

Superconducting receiving front-end partition refrigeration structure and implementation method thereof

Technical Field

The invention relates to the technical field of superconducting receiving front ends, in particular to a superconducting receiving front end partition refrigeration structure and an implementation method thereof.

Background

The high-temperature superconducting receiving front end is an important application system based on a superconducting electronic technology. The superconducting receiving front end consists of devices such as a superconducting filter, a low noise amplifier and the like, and the multichannel superconducting receiving front end also comprises devices such as a switch and the like. The superconducting filter must operate in the liquid nitrogen temperature region (77K), and the operating environment is provided by a sealed Dewar and a refrigerator. The low noise amplifier and the switch work in a low temperature environment, so that the noise temperature and the insertion loss of the device can be greatly reduced, and the receiving sensitivity of the system is improved. The microwave switch is generally designed by adopting a PIN (personal identification number) tube or a switch single chip, and for a single-pole multi-throw microwave switch needing a decoding circuit, no matter which implementation mode is adopted, the low-temperature bearing capacity of the microwave switch is limited, when the ambient temperature is lower than 120K, the stability of the switch is poor, and indexes such as insertion loss and inter-channel isolation of the microwave switch can be deteriorated.

At present, because the integral miniaturized Stirling refrigerator used by the high-temperature superconducting receiving front end only has one cold head, common installation modes of microwave devices which work in the same Dewar and need to be cooled are as follows:

firstly, the devices such as the superconducting filter, the low-noise amplifier, the low-temperature isolator, the switch and the like are all arranged on a cold plate above a first-stage cold head, namely, the devices such as the superconducting filter, the switch and the like are all cooled to 77K. This approach has the following drawbacks: 1. the cooling time is long: the Dewar internal device (including filter, amplifier, front and back stage switches, etc.) and cold plate are synchronously cooled to liquid nitrogen temperature zone (77K), and its cooling heat capacity is large and time is long. 2. Temperature gradients are not readily achieved: experimental tests show that the temperature difference of different positions on the cold plate is not higher than 2K. The switch and the superconducting filter are both arranged on the cold plate, when the temperature of the cold head reaches the set liquid nitrogen temperature, and the filter enters a superconducting state, the switch also works near the liquid nitrogen temperature zone, so that the indexes of insertion loss, out-of-band rejection and the like are deteriorated, and even the phenomenon that the filter cannot work stably exists. 3. The requirement on the refrigerating capacity of the refrigerating machine is large: the low-temperature environment in the Dewar is provided by the Stirling refrigerator, all the devices are cooled to a liquid nitrogen temperature region, the cold quantity requirement on the refrigerator is increased, and the required working temperature can not be reached even under the condition of overhigh heat loss.

Secondly, installing the superconducting filter and the low-noise amplifier on a cold plate above the first-stage cold head, and controlling the temperature of the cold plate to be 77K (namely the temperature of the superconducting filter entering a superconducting state); the switch is supported in the Dewar by a heat-insulating support structure fixed on the bottom plate of the Dewar, namely the switch works in a vacuum environment with the temperature close to the normal temperature. Both methods do not achieve the goal of reducing the insertion loss of the switch, thereby reducing the noise performance of the receiving front end and increasing the receiving sensitivity of the receiver. This approach has the drawback of switch-induced noise increase: although the switch is installed in the Dewar, the switch is fixed on the heat insulation supporting structure, the working environment temperature of the switch is equivalent to the Dewar bottom plate temperature and is close to the normal temperature, therefore, the switch is used as a radio frequency front stage, the noise temperature contribution to the whole receiving front end is increased, and the total noise coefficient index of the system is influenced.

Therefore, the two methods do not achieve the purpose of reducing the insertion loss of the switch, thereby reducing the noise performance of the superconducting receiving front end and affecting the receiving sensitivity of the receiver.

Disclosure of Invention

The invention aims to provide a superconducting receiving front-end partition refrigeration structure and an implementation method thereof, which can solve the defects in the prior art, carry out partition refrigeration on different devices in a Dewar, enable devices such as a superconducting filter, a switch and the like to work normally and obtain a lower system noise coefficient index.

In order to achieve the purpose, the invention adopts the following technical scheme:

a superconducting receiving front-end partition refrigeration structure comprises a cylinder, a primary cold head arranged at the top of the cylinder, a primary cold plate arranged above the primary cold head, a metal ring sleeved on the outer side of the middle section of the cylinder and tightly matched with the cylinder, and a secondary cold plate connected with the outer side wall of the metal ring through a secondary supporting cold head; the metal ring comprises a first metal ring part and a second metal ring part which are coaxial and are sequentially arranged from inside to outside; the material of the first metal ring part is the same as that of the cylinder; the material of second metal ring portion is the same with the material of second grade support cold head and second grade cold drawing.

Further, the cylinder and the first metal ring part are made of stainless steel materials.

Furthermore, the first-stage cold plate, the second-stage support cold head and the second metal ring portion are made of oxygen-free copper materials.

Furthermore, the secondary support cold head comprises a first support cold head which is sleeved on the periphery of the metal ring and is in close fit with the periphery of the metal ring and a second support cold head which is arranged above the outer end part of the first support cold head; the second-stage cold plate is arranged above the second support cold head.

The invention also relates to an implementation method of the superconducting receiving front-end partition refrigeration mechanism, which comprises the following steps:

(1) calibrating the temperature of different positions on the cylinder: a first temperature sensor is arranged on the primary cold head, and a plurality of second temperature sensors are arranged at different heights of the outer side wall of the cylinder; and the driving controller is adopted to control the refrigerating machine to cool, and when the temperature of the primary cold head measured by the first temperature sensor is T1 required to be maintained by the primary cold head, the temperatures of different height positions of the cylinder are measured by the plurality of second temperature sensors and are calibrated.

(2) A secondary cold head is led out from the cylinder: determining the temperature T2 required to be maintained by the secondary cold head, fastening the metal ring at the position with the temperature T2 on the cylinder, arranging the secondary support cold head on the periphery of the metal ring, and installing a secondary cold plate above the secondary support cold head.

Furthermore, the temperature of the primary cold plate and the secondary cold plate is adjusted and controlled by driving the refrigerating machine and adjusting the installation position of the metal ring on the cylinder.

According to the technical scheme, the two-stage cold head structure of the Stirling refrigerator is designed, so that different devices in the Dewar are refrigerated in a partitioned mode, the temperature difference distribution in the Dewar is achieved, different temperature requirements of the different devices in the Dewar are met, the requirement for rapid refrigeration of the front end of the superconducting receiver can be met, and the low system noise coefficient index is obtained. The secondary cold head in the refrigeration structure is formed by pressing stainless steel and oxygen-free copper, the material of the inner layer of the metal ring is the same as that of the cylinder, and the material of the outer layer of the metal ring is the same as that of the secondary cold plate and the support cold head, so that the extrusion of low-temperature deformation on the cylinder or the poor contact between the metal ring and the secondary cold plate can be avoided, the refrigeration effect of the refrigerator is ensured, and the heat conduction efficiency is improved.

Drawings

FIG. 1 is a schematic diagram of cylinder temperature calibration;

FIG. 2 is a schematic structural diagram of a superconducting receiver front-end zone cooling structure;

FIG. 3 is a schematic structural view of an eight-channel HTS receiver front end;

fig. 4 is a schematic view of the state of use of the present invention.

Wherein:

100. the device comprises a primary cold head, 101, a first temperature sensor, 102, a primary cold plate, 200, a cylinder, 201, a second temperature sensor, 202, a metal ring, 203, a first supporting cold head, 204, a secondary cold plate, 205, a first metal ring part, 206, a second metal ring part, 207, a second supporting cold head, 300, a driving controller, 400, a first low-temperature component, 500, a second low-temperature component, 600, a single-pole eight-throw switch, 700, a superconducting filter, 800 and a low-temperature low-noise amplifier.

Detailed Description

The invention is further described below with reference to the accompanying drawings:

the invention relates to a partition refrigeration structure of a superconducting receiving front end and an implementation method thereof.

Specifically, the temperatures of different positions on the cylinder of the refrigerator are calibrated firstly. According to the principle of the integrated cylinder piston type refrigerator, when the refrigerator is used for cooling, the temperatures of different positions of the cylinder are gradually increased from top to bottom. As shown in FIG. 1, a first temperature sensor 101 is installed on a primary cold head 100, and a plurality of second temperature sensors 201 are installed on different heights of the outer side wall of a cylinder 200. The driving controller 300 is adopted to control the refrigerating machine to cool, and when the temperature of the primary cold head 100 measured by the first temperature sensor 101 is the maintaining temperature T1 required by the primary cold head 100, the temperatures of different height positions on the surface of the cylinder 200 are measured by the plurality of second temperature sensors 201 and calibrated.

In the second step, a secondary cold head is led out of the cylinder 200. As shown in FIG. 2, the required maintenance temperature T2 of the secondary cold head is determined according to the requirement, a metal ring 202 is fastened on the cylinder 200 at the calibrated temperature T2, and the secondary support cold head extends from the metal ring 202. The secondary support cold head comprises a first support cold head 203 connected with the outer side wall of the metal ring 202, and a second support cold head 207 arranged above the outer end part of the first support cold head 203, and a secondary cold plate 204 is arranged above the second support cold head 207. The second cryogenic assembly 500 is mounted on the second cold plate 204 and the first cryogenic assembly 400 is mounted on the first cold plate 102.

The close fit of the metal ring 202 to the face of the cylinder 200 is critical to efficient cooling and temperature maintenance of the secondary support coldhead, which requires that the metal ring 202 be in a seamless fit with the cylinder 200 and cannot extrude the cylinder 200. Usually, the first-stage cold plate and the second-stage cold plate are made of oxygen-free copper materials with high thermal conductivity, but the thin-wall cylinder is made of stainless steel, and the thermal expansion coefficients of the two materials are different, so that the invention designs the multilayer-structure metal ring made of various materials. The metal ring is formed by pressing stainless steel and oxygen-free copper. The first metal ring part 205 of the metal ring 202 close to the thin-wall cylinder 200 is made of stainless steel material which is the same as the material of the cylinder 200, so as to avoid cylinder extrusion deformation caused by different deformation amounts of different materials at low temperature, damage to a refrigerator or poor refrigeration effect caused by poor contact between the cylinder and the copper ring. The oxygen-free copper material has high thermal conductivity and small material hardness, so the second metal ring part 206, the secondary support

cold heads

203 and 207 and the secondary cold plate 204 are fastened by the material, and a good heat conduction effect can be realized through precision machining. In order to reduce radiation heat leakage and effectively control the temperature in the Dewar, the surface emissivity of an object is reduced by adopting a multi-layer material wrapping mode, so that the radiation heat leakage is reduced.

As shown in fig. 4, the four-channel high-temperature superconducting receiving front end includes a single-pole eight-throw microwave switch, a superconducting filter, a low-temperature low-noise amplifier, and a single-pole eight-throw switch 600.

The superconducting filter 700 works in a liquid nitrogen temperature zone (77K), and when the temperature of the switch 600 is about 120K, the insertion loss is reduced to half of the normal temperature, and the working state is stable. Therefore, the SZZ10000 type Stirling refrigerator for high-temperature superconduction is cooled, when the temperature of the primary cold head 100 collected by the first temperature sensor 101 is 77K, the temperature of different heights of the surface of the cylinder 200 is measured and calibrated, the metal ring 202 which is made of stainless steel and oxygen-free copper through special process pressing is fastened at the calibration temperature of 120K, the metal ring 202 extends out of the secondary support

cold heads

203 and 207 and the secondary cold plate 204, the single-pole eight-throw switch 600 is fixed on the secondary cold plate 204, and the superconducting filter 700 and the low-temperature low-noise amplifier 800 are installed on the primary cold plate 102. In fig. 4, bold lines indicate rf connection lines, and arrows indicate rf signal transmission directions.

The above-mentioned embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solution of the present invention by those skilled in the art should fall within the protection scope defined by the claims of the present invention without departing from the spirit of the present invention.

Claims

1. A superconductive receiving front end partition refrigeration structure is characterized in that: the cooling device comprises a cylinder, a primary cold head arranged at the top of the cylinder, a primary cold plate arranged above the primary cold head, a metal ring sleeved on the outer side of the middle section of the cylinder and tightly matched with the cylinder, and a secondary cold plate connected with the outer side wall of the metal ring through a secondary supporting cold head; the metal ring comprises a first metal ring part and a second metal ring part which are coaxial and are sequentially arranged from inside to outside; the material of the first metal ring part is the same as that of the cylinder; and the material of the second metal ring part is the same as that of the second-stage support cold head and the second-stage cold plate.

2. A superconducting receiver front-end zoned refrigeration structure according to claim 1, wherein: the cylinder and the first metal ring part are made of stainless steel materials.

3. A superconducting receiver front-end zoned refrigeration structure according to claim 1, wherein: the first-stage cold plate, the second-stage support cold head and the second metal ring portion are made of oxygen-free copper materials.

4. A superconducting receiver front-end zoned refrigeration structure according to claim 1, wherein: the secondary support cold head comprises a first support cold head and a second support cold head, wherein the first support cold head is sleeved on the periphery of the metal ring and is in close fit with the periphery of the metal ring, and the second support cold head is arranged above the outer end part of the first support cold head; the second-stage cold plate is arranged above the second support cold head.

5. The method for realizing the partition refrigeration structure of the superconducting receiving front end according to any one of claims 1 to 4, wherein the method comprises the following steps: the method comprises the following steps:

(1) calibrating the temperature of different positions on the cylinder: a first temperature sensor is arranged on the primary cold head, and a plurality of second temperature sensors are arranged at different heights of the outer side wall of the cylinder; the driving controller is adopted to control the refrigerating machine to cool, and when the temperature of the primary cold head measured by the first temperature sensor is T1 which is required to be maintained by the primary cold head, the temperatures of different height positions of the cylinder are measured by the plurality of second temperature sensors and are calibrated;