2018/08/01 (Wednesday)

Previous Day

	status: room temperature, preparing for cooldown
1006	Remove LHe trap from main bath. Insert cleaned 1/4“ rod into LHe trap mounting location to ensure baffles are in the proper position in the dewar. The lowest baffle hole may be shifted slightly east from where it should be, but it seems minor. However, the LHe trap itself is found to be somewhat bowed as seen below. It seems like the bottom 1/2 of the trap bows in the same direction as the inlet/outlet connections at the top. This results in a ~1.5 cm deflection of the trap bottom from true.
1020	Gently bend the trap straight again by hand. Carefully replace trap into dewar and it fits all the way in!

Before	After

1307	Pump out fridge lines with scroll pump.
1309	Open dump to both sides of fridge lines via LN2 cold trap 2.
1313	With 1K Pot speedivalve and needle valve closed, pump on Main bath with scroll pump. Once P2 < 100 mbar, open 1K pot speedivalve and needle valve (5 turns) to pump out 1K pot volume.
1325	P2 < 1 mbar, close V1A, 1K Pot speedivalve. Pump out lines up to 4He gas line. Close off scroll pump. Flush MB and 1K pot with 140 mbar of 4He gas.
1328	Let's pump and flush once more. (This is what Goldman Lab does) Again, with 1K Pot speedivalve and needle valve closed, pump on Main bath with scroll pump. Once P2 < 100 mbar, open 1K pot speedivalve and needle valve (5 turns) to pump out 1K pot volume.
1130	P2 < 1 mbar, close V1A, 1K Pot speedivalve. Pump out lines up to 4He gas line. Close off scroll pump. Flush MB and 1K pot with 155 mbar (above 1 atm) of 4He gas.
1354	Let 5.4 mbar He exchange gas into IVC
1400	MC(Cernox) = 296.8 K, Sorb = >249 K (max), IVC = 5.4 mbar, G1 (fridge) = 614 mbar, Old Level resistor = 0.995 kΩ, New level resistor = 2.120 kΩ
1402	Begin LN2 transfer
1406	Fridge heaters are still on. Turn off MC and Still heaters.
1420	MC(Cernox) = 296.5 K, Sorb = >249 K (max), IVC = 5.4 mbar, G1 (fridge) = 612 mbar, Old Level resistor = 0.996 kΩ, New level resistor = 2.124 kΩ
1445	MC(Cernox) = 284.1 K, Sorb = >249 K (max), IVC = 4.6 mbar, G1 (fridge) = 611 mbar, Old Level resistor = 1.009 kΩ, New level resistor = 2.224 kΩ
1500	MC(Cernox) = 257.0 K, Sorb = >249 K (max), IVC = 3.4 mbar, G1 (fridge) = 610 mbar, Old Level resistor = 1.021 kΩ, New level resistor = 2.307 kΩ
1654	MC(Cernox) = 115.8 K, Sorb = 176.8 K (max), IVC = 1.6 mbar, G1 (fridge) = 604 mbar, Old Level resistor = 1.294 kΩ, New level resistor = 2.972 kΩ
1735	MC(Cernox) = 97.3 K, Sorb = 136.3 K (max), IVC = 1.6 mbar, G1 (fridge) = 602 mbar, Old Level resistor = 1.330 kΩ, New level resistor = 2.986 kΩ
1750	MC(Cernox) = 92.4 K, Sorb = 130.4 K (max), IVC = 1.6 mbar, G1 (fridge) = 601 mbar, Old Level resistor = 1.337 kΩ, New level resistor = 2.989 kΩ
1755	Cease LN2 transfer.

Cryocleaning mixture
0938	Put trap 2 in LN2 dewar. Fill LN2 cold trap dewar full.
0945	Start cleaning mixture through cold LN2 Trap 2, V6 = 12.4%
0950	Increase V6 = 12.8% to speed up cleaning
0956	Increase V6 = 13.0% to speed up cleaning
1016	Increase V6 = 13.1% to speed up cleaning
1154	Stop cleaning through cold trap 2 after 69 min. Pump mix to dump.
1105	9.1 mbar from yesterday's last cleaning in warm trap 1. Pump out trap 1.
1115	Start cleaning mixture through cold LN2 Trap 1, V6 = 13.0%
1122	Increase V6 = 13.2% to speed up cleaning
1215	Stop cleaning through cold trap 1 after 60 min. Pump mix to dump.
1235	6.4 mbar in warm trap 2. Pump out trap 2.

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