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2016/05/13 (Friday)

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Status: Fridge warming. All valves closed and pumps off. Fridge contents have been pumped to dump. LN2 traps still cold - there may still be mix in the traps, not sure whether David pumped that mix to dump yesterday.
0855 Tower = 9.3 K, 1K Pot > 7 K, Sorb = 23.5 K. Main Bath < 0%
0930 Repeating QET resistance measurements at 9.3K
Conductance from QET biases to ground [nS]
PA PB PC PD
DIB1* 0.08 0.11 0.10 0.06
DIB2 0.08 0.07 0.08 0.08
DIB3# 0.07 0.07 0.08 0.08

#DIB3 measurements were all initially ~0.12 nS, but fell upon repeating measurements.

*Returning to DIB1 found all < 0.08nS

Intra-dib, inter-channel QET bias conductances were all < 0.07 nS except: DIB1 PA→PB = 0.13 nS. DIB2 PA→PB started at 27nS and steadily fell to 17nS over ~5min. DIB3 PB→PC was unstable around 1.00-1.62 nS. All three of these outliers had previously been found to have higher conductivities at base temperature.
1200 Fill LN2 cold trap full so we can pump out the cold trap 1 to get out all remaining mixture.
1230 Turn on He3 circulation pump and open V9. 779mbar of mixture in dump. Open V12A, cold trap 1 speedivalve, and V5 to pump on cold trap 1.
1330 Cease pumping out cold trap isolate dump and turn off 3He pump 786mbar of mixture in dump. Remove cold trap1 from LN2 bath.
1340 Open Trap1 to G1 through V12A+speedivalve. Also open Trap2 to G1 through V12B+speedivalve.
1445 Not sure why Trap2 was opened to G1… this one is still cold, so the contaminants from Trap1 will simply get trapped into Trap2. So, take Trap2 out of LN2 bath to warm up also.
1500 G1 (traps) = 25 mbar and rising. Trap1 is pretty warm, Trap2 still frosty at the bottom
1530 G1 (traps) = 35 mbar and flattening. Trap2 a little cool to the touch.
1600 G1 (traps) = 35 mbar. Pump out traps with 4He pump through valves 5a, 2a, 7, 2.
1625 G1 down to 1 mbar and flat - traps are clean. Close all valves and turn off pump. (Noticed that the 4He pump outlet was set to Exhaust instead of Recovery - that's good. Probably should have checked earlier.)
1630 Tower = 17 K, Sorb = 42 K

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