Raytheon Rsp2 Cryocooler Low Temperature Testing and Design Enhancements

Abstract

The High Capacity Raytheon Stirling / Pulse Tube Hybrid 2-Stage cryocooler (HC-RSP2) was originally developed to provide simultaneous cooling at temperatures of 85 K and 35 K. During testing performed in 2008 it was demonstrated that this stockconfiguration cryocooler is capable of providing significant amounts of heat lift at 2 nd stage temperatures as low as 12 K, and modeling indicated that minor changes to the 2 nd stage inertance tube / surge volume setup could yield improved performance. These changes were implemented and the cooler was successfully retested, producing >350 mW of heat lift at 12 K. A comprehensive redesign of the system has been performed, the result of which is a robust 2-stage cryocooler system that is intended to efficiently produce relatively large amounts of cooling at 2 nd stage temperatures <12 K. This cryocooler, called the Low Temperature RSP2 (LT-RSP2) will be fabricated and tested over the next 12 months. This paper reports on the recently-completed test activities, as well as details relating to the system redesign. Expected performance, mass and packaging volume are addressed.