EMAS Stirling Cooler OperationsFeb 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-MASTurbo Pumping Station

CFM Probe

E-MAS CryoTel GT Stirling Cooler Operation

4

Tripp Lite Portable AC Unit

Environmental Cover

Turbo Pumping Station

CFM ProbeAllStar RB-2 Blower

E-MAS CryoTel GT Stirling Cooler Operation

5

E-MAS CryoTel GT Stirling Cooler Operation

6

E-MAS CryoTel GT Stirling Cooler OperationFinal test data after Indium installation

7

• Notes:• Times listed above do not match previous

charts. The cryocooler was secured at ~2100 which matches 10.98 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