MIXED GAS REFRIGERANT SYSTEM FOR SENSOR COOLING BELOW 80ºK

Abstract

The present invention discloses multi-component gas mixtures adapted to provide condensed phase cryogenic refrigerants with normal boiling points below about 80° K. for cooling sensor device components. Exemplary gas mixtures generally include 19-40% Ar and 20.1-80.5% Ne. Open-loop Joule-Thomson systems in accordance with the present invention may be suitably adapted (with varying relative mass ratios of cryogenic gas mixtures) for cooling sensor devices to temperatures between 27° K. (100% Neon) and about 80° K. (0% Neon).

1 . An open-loop Joule-Thomson system for cooling sensor devices to temperatures below about 80° K., said system comprising: 
 a vessel containing a pressurized mixture of cryogenic gas selected from the group consisting of Ar and Ne;    a counter-flow heat exchanger configured to exchange heat between pre- and post-expanded cryogenic gas;    a reservoir configured to collect and boil-off post-expanded cryogenic gas;    an isenthalpic expansion valve configured to receive a pre-expanded cryogenic gas from said counter-flow heat exchanger for isenthalpic expansion into said reservoir; and    a sensor device component in contact with said heat exchanger for cooling said sensor device.    
   
   
       2 . The open-loop Joule-Thomson system of  claim 1 , wherein said vessel is configured for regulated release of said cryogenic gas.  
   
   
       3 . The open-loop Joule-Thomson system of  claim 1 , wherein said reservoir comprises an evaporator-reservoir.  
   
   
       4 . The open-loop Joule-Thomson system of  claim 1 , wherein the molecular weight fraction of Ar is between about 19% to about 40%.  
   
   
       5 . The open-loop Joule-Thomson system of  claim 1 , wherein the molecular weight fraction of Ne is between about 20.1% to about 81.0%.  
   
   
       6 . The open-loop Joule-Thomson system of  claim 1 , wherein the normal boiling point of the condensed phase of said cryogenic gas mixture is between about 27° K. and 77° K.  
   
   
       7 . A method for cooling sensor devices to temperatures below about 80° K., said method comprising the steps of: 
 providing a vessel containing a pressurized mixture of cryogenic gas selected from the group consisting of Ar and Ne;    providing a counter-flow heat exchanger configured to exchange heat between pre- and post-expanded cryogenic gas;    providing a reservoir configured to collect and boil-off post-expanded cryogenic gas;    providing an isenthalpic expansion valve configured to receive a pre-expanded cryogenic gas from said counter-flow heat exchanger for isenthalpic expansion into said reservoir; and    providing a sensor device component in contact with said heat exchanger for cooling said sensor device.    
   
   
       8 . The method of  claim 7 , wherein said vessel is configured for regulated release of said cryogenic gas.  
   
   
       9 . The method of  claim 7 , wherein said reservoir comprises an evaporator-reservoir.  
   
   
       10 . The method of  claim 7 , wherein the molecular weight fraction of Ar is between about 19% to about 40%.  
   
   
       11 . The method of  claim 7 , wherein the molecular weight fraction of Ne is between about 20.1% to about 81.0%.  
   
   
       12 . The method of  claim 7 , wherein the normal boiling point of the condensed phase of said cryogenic gas mixture is between about 27° K. and 77° K.