Cryocooler for Sensor Cooling in Cryo-Vacuum Test Chambers

ABSTRACT: The Air Force uses specially designed facilities to perform ground testing of infrared detector focal plane arrays at Arnold Engineering Development Center (AEDC). The current approach for cooling the detectors down to 8 K utilizes liquid helium. The systems to transport and store the liquid helium are expensive to operate and wasteful due to the loss of liquid helium to boiloff. Helium is becoming a scarce resource, so a cooling approach that does not require a significant consumption of cryogen is desired. Creare proposes to develop a cryocooler that will provide focal plane cooling down to 8 K without requiring a liquid helium supply, and will be capable of maintaining stable device temperature over temperatures from 8 K to 60 K. On the Phase I project, we will develop a set of cryocooler requirements, design a cryocooler to meet these requirements, and measure the performance of a brassboard version of the cryocooler. On the Phase II project, we plan to build, assemble, and test a prototype cryocooler. Creare is well qualified to develop and demonstrate this cryocooler technology. Successful completion of this program will enable less expensive ground testing and a significantly reduced consumption of helium at AEDC. BENEFIT: The result of this program will be an efficient, reliable, and affordable cryocooler that enables testing of focal plane arrays at AEDC down to operating temperatures of 8K without using liquid helium. Commercial applications include cooling for airborne infrared sensors, electron microscopes, and superconductors.