Passive gas-gap heat switch for adiabatic demagnitization refrigerator

Abstract

A passive gas-gap heat switch for use with a multi-stage continuous adiabatic demagnetization refrigerator (ADR). The passive gas-gap heat switch turns on automatically when the temperature of either side of the switch rises above a threshold value and turns off when the temperature on either side of the switch falls below this threshold value. One of the heat switches in this multistage process must be conductive in the 0.25° K to 0.3° K range. All of the heat switches must be capable of switching off in a short period of time (1-2 minutes), and when off to have a very low thermal conductance. This arrangement allows cyclic cooling cycles to be used without the need for separate heat switch controls.

1 . A heat switch for an adiabatic refrigeration process wherein said heat switch comprises; 
 a first conductor element;    a first set of fins integrally formed with said first conductor element;    a second conductor element;    a second set of fins integrally formed with said second conductor element; and,    a containment tube for physically supporting said first and second conductor elements.    
   
   
       2 . The device according to  claim 1  wherein said first and second sets of fins are interleaved.  
   
   
       3 . The device according to  claim 1  wherein a gap exists between said first and second sets of fins.  
   
   
       4 . The device according to  claim 3  wherein said first and second conductor elements each include a thermal interface.  
   
   
       5 . The device according to  claim 4  wherein said first and second conductor elements each include a mechanical interface.  
   
   
       6 . The device according to  claim 5  wherein said thermal interface and said mechanical interface are one in the same.  
   
   
       7 . The device according to  claim 1  wherein said containment tube is impermeable to helium gas.  
   
   
       8 . The device according to  claim 7  wherein said containment tube is hermetically sealed with said first and second conductor elements.  
   
   
       9 . The device according to  claim 1  wherein said adiabatic refrigeration process is continuous.  
   
   
       10 . The device according to  claim 9  wherein said heat switch is a passive gas-gap heat switch.  
   
   
       11 . The device according to  claim 1  wherein said heat switch is capable of conducting heat from 0.25° K to above 1° K.  
   
   
       12 . A passive gas-gap heat switch for a continuous adiabatic refrigeration process wherein said heat switch comprises; 
 a first conductor element;    a first set of fins integrally formed with said first conductor element;    a second conductor element;    a second set of fins integrally formed with said second conductor element wherein said first and second sets of fins are interleaved and do not touch; and    a containment tube for physically supporting said first and second conductor elements wherein said containment tube hermetically seals said first and second sets of fins.