Russ Rucinski, Fermilab, March 29, 2005

Commissioning is underway! –2 Cassettes installed on 3/18. –Sensors and control heater mounted. –Multi-layer super insulation blankets on. –Leak checking of vacuum jacket – passed. –Leak checking of cassette space – passed. –Cryostat is in place and hooked up.

Russ Rucinski, Fermilab, March 29, 2005 Initial cool down last Friday 3/25. Started late in the day, saw that it would cool, started debugging temperature sensor readout. Ran for 2 hours. Warmed up over the weekend. Started cooling on Monday 3/28 at 7:30 am, and have been cooling ever since (32 hours now). –Station 1 at 54 K. (more or less stable) –Station 2 at 16.5 K. (slowly decreasing)

Russ Rucinski, Fermilab, March 29, 2005 Sensors 1 & 2 are redundant 100 Ohm Allen Bradley carbon resistors. They are on stage 2 cold head and thermal link. They agree to a few tenths of a Kelvin. Sensor 3 is a silicon diode on the upper intercept. Cooling rate had slowed to -0.1 K/hr earlier today. But now at -0.4 K/hr. Maybe attributed to isolating the vacuum jacket from the turbo cart, or lowering lid heater setpoint by 5 C, or due to something else.

Russ Rucinski, Fermilab, March 29, 2005

Plans –Continue to cool, and obtain coldest temperatures. –Read out cassette temperature sensors independently. –Get heater control loop functioning. –Install low cassette space pressure alarm. If Problems: –Capacity issue? Run without thermal link to cassette. –Heater attachment location may be suspect. –Sensor self heating issue? –More MLI on sides needed? (shell a few C cold on sides)

Russ Rucinski, Fermilab, March 29, 2005

Sensor 1 – cold end Sensor 2, thermal link Sensor 3, upper Control heater