Publisher Summary
This chapter helps in constructing 4-valve type 2-stage pulse tube refrigerator that has two sets of phase shifting system for the study of multi-staging of pulse tube refrigerator. It is found that a finite phase difference between 1st and 2nd pulse tube is effective for achieving higher performance. By the optimization of two phase shifters, around 9K of the lowest temperature is achieved with normal lead regenerator. The chapter also evaluates the 1st stage cooling performance (the reachable temperature and the cooling power) from the viewpoint of its dependence on the size of 1st pulse tube, and its strong dependence is found. By choosing suitable 1st pulse tube size and phase shifting, cooling powers of the 1st and 2nd stage of 22W (at 80K) and 3.0 W (at 20K) respectively, with power consumption of 2.8kW is obtained.