A 910 mW@15 K Thermal-Coupled Pulse Tube Cryocooler with Active Phase Shifter

A two-stage Stirling-type pulse tube cryocooler (SPTC) operating in 15 K is developed in our lab for cooling infrared detectors and per-cooling helium JT cryocooler. The SPTC adopts thermal-coupled structure and each stage adopts a coaxial structure for compactness and convenience. For easy adjustment, the driven compressor of the SPTC is designed as two independent linear compressors. The first stage uses an inertance tube and reservoir as a phase shifter, while the second stage cold finger uses an active warm displacer (AWD) as phase shifter to maximize the cooling performance. Through reasonable design of structure and operating parameters, the SPTC achieves better performance at 15 K. The experiment also investigated the influence of the frequency. With the pre-cooling temperature of 80 K, the second stage cold finger can obtain 470 mW at cooling temperature of 15 K with a total electric input power of 250 W. It can also obtain 910 mW at cooling temperature of 15 K with total input power of 386 W. The cryocooler has obtained a large cooling capacity and high efficiency at 15 K to meet the design and application requirements.