EMAS Stirling Cooler Operations Feb 24, 2011 Mike Watson

2 E-MAS CryoTel GT Stirling Cooler Operation System Conditions EMAS under active vacuum Detectors off Lab environment air around 23-26C AC unit running pushing air to EMAS HX at inlet temperature around 7-9C Blower pulling on EMAS HX air outlet running at close to 50 CFM Environmental cover not installed Test Sequence Cooldown initiated from ambient conditions Cooled to steady state minimum temperature Stirling cooler secured, system allowed to warm up

3 E-MAS CryoTel GT Stirling Cooler Operation Tripp Lite Portable AC Unit EMAS Heat Exchanger AllStar RB-2 Blower E-MAS Turbo Pumping Station CFM Probe

E-MAS CryoTel GT Stirling Cooler Operation 4 Tripp Lite Portable AC Unit Environmental Cover Turbo Pumping Station CFM Probe AllStar RB-2 Blower

E-MAS CryoTel GT Stirling Cooler Operation 5

6

E-MAS CryoTel GT Stirling Cooler Operation Final test data after Indium installation 7 Notes: Times listed above do not match previous charts. The cryocooler was secured at ~2100 which matches hours in charts. Cryocooler automatically shuts down at 70C (Cooler Temp). Cold head Casing to Clamp (W/K) conduction value >2x with the installation of indium over thermal gap pad. Earlier testing indicated that there is still value additional air flow. AC unit did shut down occasionally, (compressor only, fan still runs) presumably due to a low temperature condition. Unit restarted itself within a few minutes and did not require any cold head power adjustments. We need to watch these calculated values over time to ensure the indium joints are not changing

E-MAS CryoTel GT Stirling Cooler Operation 8 Potential upgrade paths Remake fins and clamps Upgrade to copper Thicker clamp cross section Less indium in joint Start over with SunPower clamp system Would likely need some customization Could integrate a liquid path integral within copper clamps