Description: West Coast Solutions (WCS) and Raytheon propose to leverage the existing, proven, high performance Raytheon Low Temperature Stirling / Pulse Tube Two-Stage (LT-RSP2) cryocooler as an extremely well-informed starting point to develop a new high capacity, sub-10 K linear cryocooler that takes advantage of the latest innovations at WCS and elsewhere in terms of regenerator technology and advanced modeling techniques. The resulting Sub-10 K (S10) Cryocooler will feature unmatched thermodynamic efficiency (>6.6% Carnot @ 10 K), and by utilizing the hybrid Stirling / pulse tube cold head arrangement, it will provide unique operational flexibility to efficiently operate over a wide range of temperatures. This combination makes the S10 Cryocooler the ideal cryocooler for 8-10 K applications (maybe lower) as well as the optimum upper-stage cooler for 4-6 K applications.

Benefits: High performance, multistage, low temperature (4 to 10 K) cryocoolers are required for many Deep Space Astronomy missions. While upper stages are typically used to cool optics and act as thermal intercepts for lower stages, the lowest ~ 4 K stage is increasingly being used at the heat sink for an adiabatic demagnetization refrigerator (ADR) that produces the ultimate cooling to ~ 50 mK. One example is the Line Emission Mapper (LEM), which is planning to use a 4-stage pulse tube that bottoms out at 4.5 K as the ADR heat sink. Another example is the Galaxy Evolution Probe (GEP), which requires ~80 mW @ 4 K (for the ADR heat sink) and ~500 mW @ 20 K for the optics. The proposed effort squarely addresses this need for improved Deep Space Astronomy cryocooler solutions by collaborating with Raytheon to develop an advanced linear cryocooler capable of operating from 4 K to 10 K. The S10 Cryocooler is expected to have relevance for Department of Defense Intelligence, Surveillance, and Reconnaissance (ISR) missions featuring very long wave infrared (VLWIR) blocked impurity band (BIB) detectors, such as doped Silicon (Si:As, Si:Sb) and doped Germanium (Ge:Ga, Ge:B) detectors, which typically reauire sub-20 K cooling.