Development of 30mW@4K hybrid J-T cooler for space application

In the area of space astronomy, some electronic detectors should be cooled to liquid helium temperature level to improve their sensitivity and reduce the background noise. A hybrid J-T cooler has been developed for future space application by our laboratory. The J-T loop is precooled by two-stage thermally coupled pulse tube cooler. There is no moving part at low temperature in this system which features low vibration electromagnetic interference. The hybrid J-T cooler has been experimental tested and cooling capacity of about 34.5mW@4.32K is achieved when supply pressure is 1.97MPa. Besides, when sufficient precooling power is provided for the J-T loop cooling capacity of 102.3mW at 5.02K is achieved. In this experiment, three oil free linear compressors are used to drive the J-T loop and a GM cooler is used to provide the precooling power for the J-T cooler. This J-T cooler will be the potential cryocooler for the future space detectors requiring cooling power of 100mW at < 6K.