2016/08/29 (Monday)

Previous Day

	Setup: DIB1/2/3 → 3.2 MHz filters → nothing/disconnector board/remapping board → HVside2board → DCRC55(1)/50(3). Disconnector board has all charge lines disconnected.
	DCRCs powered overnight. Not pumping on IVC.. Stopped circulation, and 1K Pot to allow warm up.
0915	Tower= 4.6 K, Still = 24 μbar, G1/G2 = 9.0/548 mbar (V9 closed), 1K Pot = 4.2 K / 0.5 mbar, MB = 1.2%. IVC=2.2 μbar.
0950	Lower Dewar.
0954	With tower temperature of 40K after lowering dewar, IVC=0.14 mbar. Turn on leak checker.
1030	Perform electrical check with tower at 80K. All measurements as before except those mentioned below.
	DIB1: QIbias→QObias=10nS, QIbias→QETret<1nS QIfb→Drain/Source <1nS, QIfb→chassis=14Ω QETrets→chassis~3nS QETB→Ret = 200Ω
	DIB2: QETB→ret=open, 70Ω, open, 71Ω QIfb→Drain/Source <1nS, QIfb→chassis <1nS QOfb→Drain/Source=20nS, QOfb→chassis<1nS FET Tsense+→FET heater- = open, QET rets→chassis ~3nS
	DIB3: Squid Bias D/ret unstable (2-20 kΩ) QETs/QETrets→chassis ~3nS
1044	Filling LN2 cold trap to keep the gunk frozen.
1054	8.5mbar was in P1 due to fridge warm up, pumping it to dump.
1155	Tower temp = 195K. IVC pressure = 1.9mbar. Commence pumping on IVC with scroll pump.
1205	Switch to turbopumping IVC.
	G2: 775mbar. Commence pumping whatever may be left in LN2 cold traps to dump (both cold trap 1 & 2) through V12A/B, both cold trap speedivalves, and V5.
1335	Close V12A/B and cold trap speedivalves, V5, and begin closing V6 in preparation for throughput test. G1: ~1mbar, G2: 780mbar, P1: 6ubar.
	Calibrate Leak Checker and open it to the IVC. Isolate Turbopump, so we're only pumping on the IVC with the leak checker.
1340	Background leak rate stabilizes at 1.1E-6 mbarL/s. Restart pumping on IVC with turbopump.
1436	G2: 783mbar in dump. Isolate dump. Pump out lines leading from P2 to Cold Traps 1 & 2 (V5A, 2A, V7). Once pumped down, close manual valve on He4 pump and power off. Open V11A/B to open Cold Traps to P2. Remove cold traps from LN2 bath and allow to warm up.
1510	With IVC pressure down to 8.6e-5 mbar, attempt to switch to leak checker to obtain background rate and start leak check. Background rate was at ~1e-6 mbarL/s which is TOO DAMN HIGH. Switch back to turbopump, and see that IVC pressure has risen to 8.6E-4 mbar. Not sure if this is due to switching to the leak checker and back, or due to temperatures rising. Let's leave this alone a while longer.
1520	Perform an electrical check with tower at 230K. All measurements as before except those mentioned below.
	DIB1: QIbias→QObias=13nS, QIbias→QET ret=25nS QIfb→Drain/Source <1nS, QIfb→chassis=2.5Ω QET ret→chassis~6nS SquidC/SquidC ret→chassis~6nS QETB→ret = 5MΩ or open Last QETB ret→chassis 2Ω (short) QiBias→chassis=6 nS and QiBias/QoBias→QET ret=25 nS
	DIB2: QETB→ret=open, 89Ω, 103Ω, 90Ω QIbias/Qobias→ret=25 nS (instead of <1 nS) QIfb→Drain/Source=23/23nS, QIfb→chassis <1nS QOfb→Drain/Source=25nS, QOfb→chassis<1nS FET Tsense+→FET heater- = 0.75V (normal), QET rets→chassis ~5nS SquidA/SquidA ret→chassis=5 nS
	DIB3: Squid Bias D→ret (now stable) 3.1kΩ QETs/QETrets→chassis ~6nS QIfb/QOfb→chassis <1nS Bfb/Bfb ret→chassis~6nS
1538	P2 reads 45mbar. Turn on He4 pump and open manual valve to begin pumping on warm cold traps.
1605	With tower temperature at 234 K and background leak rate of 3.4e-7 mbarL/s (IVC pressure down to 5.4e-4 mbar), conduct spray test on IVC cans and upper flanges. No sign of any leak, with leak rate slowly decreasing over time to 3.2e-7 mbarL/s.
1627	Cease pumping on LN2 cold traps. Close all valves on IGH, and return traps to LN2 bath. Fill LN2 cold trap full.
1639	Turn off mixing chamber heater and still heater in preparation for throughput leak check. Background leak rate at 3.5e-7 mbarL/s.
1645	Conduct throughput leak check through cold trap2, closing gate valve to force mixture to linger in the fridge lines. No leak/spike in leak rate was detected. Open gate valve and V3 to fully flush the mix through the fridge lines, still no indication of a leak. Commence pumping mixture back to dump through both sides of the fridge.
1658	Add 10 mbar N2 exchange gas to IVC to warm up overnight. Tower temperature currently at 237 K.
1744	Tower temp = 251K. G2 at 786mbar. Close V9 and turn off He3 pump.

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