Cryocooling system

Abstract

A cryocooling system includes a compressor, a refrigerator, and a controller, which is communicatively coupled to the compressor and the refrigerator. The compressor is configured to be driven at a drive frequency. The refrigerator is coupled to the compressor via a first fluid path and includes a cold heat exchanger, an output, a reservoir, and a flow resistor. The flow resistor controls fluid flow along a second fluid path between the output and the reservoir. The controller optimizes a rate of cooling of the cold heat exchanger by adjusting both a drive frequency of the compressor and a resistance of the flow resistor along the second fluid path.

We claim: 
     
         1 . A cryocooling system comprising:
 a compressor configured to be driven at a drive frequency;   a refrigerator coupled to the compressor via a first fluid path and including a cold heat exchanger, an output, a reservoir, and a flow resistor that controls fluid flow along a second fluid path between the output and the reservoir; and   a controller, communicatively coupled to the compressor and the refrigerator, that optimizes a rate of cooling of the cold heat exchanger by adjusting both a drive frequency of the compressor and a resistance of the flow resistor along the second fluid path.   
     
     
         2 . The cryocooling system of  claim 1 , the compressor being a rotary valve compressor. 
     
     
         3 . The cryocooling system of  claim 1 , wherein the controller dynamically optimizes the rate of cooling as a temperature of the cold heat exchanger changes. 
     
     
         4 . The cryocooling system of  claim 1 , wherein the controller dynamically optimizes the rate of cooling until a temperature of the cold heat exchanger decreases to a steady-state target temperature that is less than six Kelvin. 
     
     
         5 . The cryocooling system of  claim 1 , wherein:
 the compressor is a rotary valve compressor; and   the controller dynamically optimizes the rate of cooling as a temperature of the cold heat exchanger changes.   
     
     
         6 . The cryocooling system of  claim 1 , wherein:
 the compressor is a rotary valve compressor; and   the controller dynamically optimizes the rate of cooling until a temperature of the cold heat exchanger decreases to a steady-state target temperature that is less than six Kelvin.   
     
     
         7 . The cryocooling system of  claim 1 , wherein the refrigerator comprises multiple cooling stages and the resistance along the second fluid path is optimized in at least one of the multiple cooling stages. 
     
     
         8 . The cryocooling system of  claim 1 , wherein the flow resistor includes an orifice valve. 
     
     
         9 . The cryocooling system of  claim 1 , wherein the refrigerator receives an oscillatory fluid flow from the compressor. 
     
     
         10 . The cryocooling system of  claim 1 , the refrigerator comprising a regenerator, a thermal buffer tube, and an input coupled to the compressor via the first fluid path.