Chapter 60 - Characteristics of 4 K pulse tube cryocoolers in applications

Abstract

This chapter introduces the Cryomech 4 K pulse tube cryocoolers and their performances. The characteristics of the cryocoolers in applications are presented and compared with 4 K GM cryocoolers. Cryomech has developed and commercialized 4 K pulse tube cryocoolers, Models PT403, PT405, PT407 and PT410, which provide cooling capacities from 0.25 W to 1.0 W at 4.2K. The latest developments at Cryomech have enabled the pulse tube cryocoolers to have almost the same capacity and efficiency as GM cryocoolers. The 4 K pulse tube cryocoolers have opened many challenging applications and demonstrated their advanced features with respect to very low vibration, low magnetic field distortion, and long MTBM. It has no moving parts at cryogenic temperatures and leads to advanced features over the 4 K GM cryocooler. These 4 K pulse tube cryocoolers have opened many challenging applications in cooling NMR and MRI magnets, precooling dilution refrigerator, ADR and sorption cooler, cooling sensitive devices like SQUID magnetometer, etc. These applications demonstrate great advantages of pulse tube cryocoolers over GM cryocoolers in the field.