Multi-Stage Pulse-Tube Cryocoolers or Sensor and Electronics Applications

Sunpower proposes to investigate the feasibility of highly-efficient multi-stage pulse-tube cryocoolers for cooling loads in the range of 10 to 100 mW at temperatures of 10 to 12 K, satisfying the requirements of NASA SBIR subtopic 17.04, Thermal Control and Cryogenic Systems. These cryocoolers will employ low-cost and reliable linear-motor, gas-bearing compressors operating in the range of 40 to 60 Hz with electrical inputs on the order of 100 W or lower. In the expander section, each stage will comprise a regenerator and pulse-tube in a u-tube configuration fitted to an inertance-tube phase shifter and reservoir volumeAchieving high efficiencies at these relatively low cooling powers will require special care to minimize thermal losses. Integral with the cryocooler design, Sunpower proposes to investigate the cryo-package design, including the physical dimensions of the likely cooled device as well as the optimal insulation strategy. To maximize overall system efficiency, intermediate-stage cooling will anchor radiation shielding at each intermediate-stage temperature, where radiant heat loading can be removed more efficiently.This project will employ the Sage pulse-tube design software (Gedeon Associates) for the multi-stage cryocooler modeling as well as the overall cryo-package optimization.