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2016/04/14 (Thursday)

Previous Day

Overnight: pumping IVC, both sides, with scroll pump
0900 IVC pumping pressure 3.4 E-3 mbar. Valve out pump: IVC pressure = 10 E-3 mbar.
0910 Turn on leak detector
0920 Electrical check at breakout box, all still looks OK
0920 Start pumping IVC with turbo pump
0935 IVC pumping pressure 86 E-6 mbar
0945 LD on IVC, background 14 pbarL/s
0955 Leak check all connections at top of fridge and IVC seals above top of mini cleanroom - no leaks seen.
1000 Pump on IVC with turbo again
1100 Vacuum inside MB and raise MB
1120 IVC pumping pressure 54 E-6mbar
1200 After much finagling, finally get Dewar in place. New procedure: place and tighten smallest dewar screws first in order to get alignment and tilt correct. Then big screws, then middle screws. Once all are in place, tighten all from biggest to smallest. After this coming run, we need to address the tilt and off-center nature of the dewar. It's gotten out of hand.
1210 Fill LN2 cold trap full.
1415 IVC pumping pressure = 46 E-6mbar. Valve out pump, IVC pressure = 6.3 E-3 mbar.
IVC pressure kinda high, I think we'll keep pumping overnight
1458 Turn on He3 pump. Commence mixture cleaning through cold trap 1.
1615 IVC pumping pressure = 40 E-6mbar. Valve out pump, IVC pressure = 8.6 E-3 mbar. (Waited longer with the valve closed this time, about 5 minutes)
1627 Commence pumping mixture to dump.
1702 G2=791 mbar, so we might want to pump to dump again tomorrow. Stop pumping to dump.

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