Mechanical vibration isolation liquid helium re-condensation low-temperature refrigeration system

Abstract

The present disclosure relates to a mechanical vibration-isolated, liquid helium recondensing cryogenic cooling system. The system according to some embodiments of the present disclosure includes: a closed-cycle cryogenic cooling system, a liquid helium recondensation cooling and vibration isolation system, and a temperature feedback control system. The present invention utilizes a closed-cycle cryogenic cooling system and may achieve low temperatures as low as 4.2 K and may consume substantially no helium gas or liquid helium. Using the cooling and vibration isolation system, liquid helium is generated and maintained through recondensation of helium gas. Not only does the technology effectively isolate the low-frequency vibrations produced by the closed-cycle cryogenic cooling system during operation, but it also resolves the issue of large fluctuations in the resulting temperature of the closed-cycle cryogenic cooling system. The disclosed technology can achieve a large-scale temperature regulation and is suitable for ultra-high vacuum environment based on high-temperature baking.

1 - 3 . (canceled) 
     
     
         4 . A cooling system, comprising:
 a closed-cycle cooling system including a closed-cycle cold head, a compressor, and a helium gas pipeline;   a cooling and vibration isolation interface containing a helium heat exchange gas configured to conduct a heat exchange between the cold head and the cooling and vibration isolation interface; and   a temperature feedback control system configured to detect a liquid helium level of a liquid helium stored in an low-temperature end of the cooling and vibration isolation interface.   
     
     
         5 . The cooling system of  claim 4 , wherein the temperature feedback control system includes at least one temperature sensor configured to detect the liquid helium level in the low-temperature end of the cooling and vibration isolation interface. 
     
     
         6 . The cooling system of  claim 4 , wherein the temperature feedback control system includes a first temperature sensor disposed below a horizontal projection plane of a design liquid helium level, and a second temperature sensor disposed above the horizontal projection plane of the design liquid helium level. 
     
     
         7 . The cooling system of  claim 4 , wherein the temperature feedback control system includes a first temperature sensor and a second temperature sensor, and temperature measurements of the first temperature sensor and the second temperature sensor are associated with the liquid helium level of the liquid helium stored in the low-temperature end of the cooling and vibration isolation interface. 
     
     
         8 . The cooling system of  claim 4 , wherein the temperature feedback control system includes a heating element disposed adjacent to the low end of the low-temperature end of the cooling and vibration isolation interface, and configured to heat the liquid helium stored in the low-temperature end of the cooling and vibration isolation interface. 
     
     
         9 . The cooling system of  claim 4 , wherein the liquid helium is generated through recondensation of the helium heat exchange gas of the cooling and vibration isolation interface. 
     
     
         10 . The cooling system of  claim 4 , wherein the helium heat exchange gas is configured to isolate a mechanical vibration of the cold head of the closed-cycle cooling system. 
     
     
         11 . The cooling system of  claim 4 , wherein the cold head of the closed-cycle cooling system extends into the cooling and vibration isolation interface. 
     
     
         12 . The cooling system of  claim 4 , wherein the closed-cycle cooling system further includes a compressor and a gas pipeline. 
     
     
         13 . The cooling system of  claim 4 , further comprising:
 a thermal heat shield disposed on the cooling and vibration isolation interface to shield radiation thermal leaks.   
     
     
         14 . The cooling system of  claim 4 , further comprising:
 a rubber sealing the cold head and a top end of the cooling and vibration isolation interface and configured to isolate a mechanical vibration of the cold head.   
     
     
         15 . A method of cryogenic cooling, comprising:
 conducting a heat exchange between a cold head of a closed-cycle cooling system and a cooling and vibration isolation interface by helium exchange gas; and   recondensing a portion of the helium heat exchange gas into a liquid helium; and   storing the liquid helium in a low-temperature end of cooling and vibration isolation interface.   
     
     
         16 . The method of  claim 15 , further comprising:
 collecting a first temperature measurement from a first temperature sensor disposed below a horizontal projection plane across the low-temperature end of cooling and vibration isolation interface; and   collecting a second temperature measurement from a second temperature sensor disposed above the horizontal projection plane.   
     
     
         17 . The method of  claim 16 , further comprising:
 detecting a liquid helium level of the liquid helium stored in low-temperature end of cooling and vibration isolation interface; and   regulating the liquid helium level through a heating element disposed adjacent to the low-temperature end of cooling and vibration isolation interface.   
     
     
         18 . The method of  claim 17 , wherein the detecting a liquid helium level comprises:
 in response to that the first temperature measurement and the second temperature measurement are above a phase transition temperature of helium gas, determining that the liquid helium level is above the second temperature sensor; and   in response to that the first temperature measurement equals the phase transition temperature of helium gas and the second temperature measurement is above the phase transition temperature of helium gas, determining that the liquid helium level is between the first temperature sensor and the second temperature sensor.   
     
     
         19 . The method of  claim 15 , further comprising:
 shielding radiation thermal leaks by a thermal radiation shield disposed on the cooling and vibration isolation interface.   
     
     
         20 . The method of  claim 15 , further comprising:
 isolating a mechanical vibration of the cold head by the helium heat exchange gas.   
     
     
         21 . The method of  claim 15 , further comprising:
 isolating a mechanical vibration of the cold head by a rubber disposed to seal the cold head and a top end of the cooling and vibration isolation interface.   
     
     
         22 . The method of  claim 15 , further comprising:
 conducting a heat exchange between the low-temperature end of cooling and vibration isolation interface and an object to be cooled and disposed below the low-temperature end.