2017/11/14 (Tuesday)

Previous Day

	Status: Tower installed, IVC pumping overnight. All mixture recovered to dump. 1K Pot needle valve closed. Cryostat vacuum jacket pumped out. Mixture cryocleaned once.
0845	Turbo = 40 nbar, pumping on IVC. IVC = 3.4 μbar with pump valved out (after 10 minutes).
0850	Open Trap 2 to G1: 340 mbar of contaminants after yesterday's 45 minute cryocleaning. Pump this out.
0915	Start cryocleaning mixture through Trap 2. V6=12.8%
0915	Quick electrical check. DIB4 pB Feedback coil/return reads open. This is a Side2 channel, so it is not critical.
0925	Cryocleaning flow stopped, increase V6 to 13.0% to reestablish circulation
0925	Leak detector is on IVC, background settles around 7.5 pbarL/s
0930	Do squirt-test leak check, no external IVC leaks found.
1005	Finish raising main bath
1010	Cryocleaning flow stopped, increase V6 to 13.1% to reestablish circulation
1025	Pump the mixture out of the trap and into the dump. Wait for G1 to stabilize.
1038	Close V12B+speedivalve, close V3, and close V6 completely.
1040	close V9, remove cold trap 2 from LN2 bath to warm up.
1047	Start cryocleaning mixture through trap 1. Open V6 to 13.1%
1110	Cryocleaning flow stopped, increase V6 to 13.3% to reestablish circulation
1150	Pump the mixture out of the trap and into the dump. Open V6. Wait for G1 to stabilize. End of cryocleaning through Trap 1, 60 minutes.
1210	Open Trap 2 (room temperature) to G1: 8.0 mbar of contaminants. Pump out with scroll pump.
1225	Verify 1K Pot needle valve closed. Pump out 1K Pot with scroll pump.
1230	Pump out fridge with scroll pump. There was a few mbar in the LHe cold trap, but no measurable amount in condenser or still.
1235	Open fridge lines up to (cold) Trap 2, to cryopump out whatever air is left in the fridge.
1240	Let mixture into fridge through Trap 2. 3He pump off, V9, V13b, V12b+speedi, V3, V1, condenser & still valves all open.
1245	Check IVC with leak detector: 11 pbarL/s. No significant leak from fridge to IVC.
1250	Pump out main bath with scroll pump. P2 falls below 1 mbar in 5 minutes.
1300	Pressurize main bath with He to 205 mbar above 1atm on G3.
note	He gas is left in the Vent volume, the auxiliary right volume, the auxiliary left (G3) volume, and the P2 volume (pump inlet).
1305	Let 5.4 mbar He exchange gas into IVC
1310	Begin LN2 transfer.
1310	MC(Cernox) = 295.7 K, Sorb = >249 K (max), IVC = 5.4 mbar, G1 (fridge) = 610 mbar, Level resistor = 0.988 kΩ.
1320	MC(Cernox) = 294.7 K, Sorb = >249 K (max), IVC = 4.6 mbar, G1 (fridge) = 610 mbar, Level resistor = 0.999 kΩ.
1340	MC(Cernox) = 263.4 K, Sorb = >249 K (max), IVC = 3.4 mbar, G1 (fridge) = 608 mbar, Level resistor = 1.033 kΩ.
1400	MC(Cernox) = 220.4 K, Sorb = >249 K (max), IVC = 2.5 mbar, G1 (fridge) = 607 mbar, Level resistor = 1.110 kΩ.
1435	MC(Cernox) = 156.3 K, Sorb = 240.5 K, IVC = 2.2 mbar, G1 (fridge) = 604 mbar, Level resistor = 1.265 kΩ.
1435	watching interchannel resistances on DIB4. pB is Side2, pC and pD are side 1. They were around 300 Ω at room temperature. Now pC-pD is around 20 kΩ and pB to the others is around 35 kΩ .
1500	MC(Cernox) = 131.0 K, Sorb = 174.1 K, IVC = 1.9 mbar, G1 (fridge) = 602 mbar, Level resistor = 1.308 kΩ.
1520	MC(Cernox) = 116.7 K, Sorb = 143.3 K, IVC = 1.9 mbar, G1 (fridge) = 601 mbar, Level resistor = 1.325 kΩ.
1530	MC(Cernox) = 111.1 K, Sorb = 133.8 K, IVC = 1.6 mbar, G1 (fridge) = 600 mbar, Level resistor = 1.330 kΩ.
	close to done with transfer. But for Run 64 we filled till the level resistor hit 1.347 kΩ, and it didn't completely hold overnight.
1545	MC(Cernox) = 104.1 K, Sorb = 125.1 K, IVC = 1.6 mbar, G1 (fridge) = 600 mbar, Level resistor = 1.335 kΩ.
1545	DIB4 pB - pC, pD around 400 MΩ, pC-pD around 1 MΩ
1600	MC(Cernox) = 98.1 K, Sorb = 120.7 K, IVC = 1.6 mbar, G1 (fridge) = 599 mbar, Level resistor = 1.337 kΩ.
1615	MC(Cernox) = 94.0 K, Sorb = 119.0 K, IVC = 1.6 mbar, G1 (fridge) = 598 mbar, Level resistor = 1.338 kΩ. Stop LN2 transfer.
	after transfer, level resistor resistance dropped a bit, to 1.306 Ω. That's strange. Was it being cooled by gas flowing past it? Maybe not actually submerged?
1625	Perform electrical check around 95 K. A few issues found:

DIB3pD Feedback coil open. But we don't care, this is not a connected channel.
DIB3pA QET short to ground (80 Ω). Not a connected channel. But we'll need to modify the HV board so that HV is not applied to this channel (remove bias resistor)
DIB3pB QET-to-QETreturn: high, 400 Ω and unstable, normal is around 25-45 Ω. (There's only one return line working for this channel on this stripline, #19). A Side2 channel, so not super-critical. It's the outer ring, so this would be sorta bad if the bias connection is gone.
DIB4pA Feedback coil high, 1.2 MΩ, normal 12 kΩ. This is not a connected channel, doesn't matter.

1640	MC(Cernox) = 88.2 K, Sorb = 117.9 K, IVC = 1.6 mbar, G1 (fridge) = 598 mbar.
1650	Mini-throughput check: close off Trap 1 and V3. Only V1, condenser speedivalve, still gate valve, and V9 open. Turn on 3He pump, then open V6 to 12.8%. This pumps mix out of the still side and we can see if the pressure goes down on the condenser side. G1 (condenser) begins falling, from 600 mbar to 560 mbar in about a minute, and continues to fall. Good, looks like we have throughput. P1 falls to 5 mbar in a couple minutes. End test and restore to previous: fridge connected to Trap 2 and dump, 3He pump off.
2100	MC(Cernox) = 77.2 K

Cryocleaning log
date	duration (minutes)	contaminants removed (mbar)
Nov 13	45	340
Nov 14	60	8.0
Nov 14	60	7.0

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