A High Efficiency Coaxial Pulse Tube Cryocooler for Cooling Medium-Wave Infrared Detectors

In order to meet the cooling demand of a medium-wave infrared detector, a coaxial pulse tube cryocooler (PTC) working at temperature around 90 K has been designed. The cooling capacity is requested to exceed 7 W at 90 K with an input electric power of 100 W. The compressor is made based on an engineering prototype which has been successfully applied in space. Experimental studies have been carried out to improve the performance of the cold finger from the aspects of inertance tube, cold-side heat exchange, hot-side flow straightener. By carrying out these optimizations the PTC can achieve a 7.64 W cooling capacity at 90 K when the input electric power is 100 W, and its relative Carnot efficiency is higher than 15% at temperature between 80 and 100 K.