2021/03/22 (Monday)

Lab in-person: Ruiren
Virtual partner: Matt

Status	Run 74 in progress. Warming the fridge a bit to pump out helium from IVC, see if that helps the short in DIB2qI that's causing noise.
	Setup: DIB1/2+acc → SL 41/43 → 3.2 MHz filters → cables 2/3 → nothing/HV_diverter_board → DCRC50(3)/~~55(1)~~. ~~Kepco 0-40V supply → HV BNC~~. No lead/poly shield.
0830	MB = 33.3%
0845	Tower = 2.26 K, flat overnight. MC heater = 20 mW. Condenser = 68 mbar. 1K Pot = 1.54 K / 6.5 mbar, flat overnight.
	We will need to close the 1K Pot speedivalve to get it warmer. But maybe we can not leave it closed too long, so that it won't take so long to pump it out when we restart it.
0850	Turn off 3He pump
1000	Tower temperature starts increasing at this time, breaking out of its plateau. 1K Pot though is still steady. (Maybe turning off the 3He pump weakened the thermal connection through the mixture gas by decreasing the pressure in the fridge.)
1210	Tower = 3.57 K, oscillating in a sorta random way between 3.4 and 3.7 K
1430	Ruiren enters lab
1430	Tower/MC/Coldplate = 3.74K/4.76K/5.79K, Still = 2.98 K / off scale / 0 mW, G1/G2 = 57/51 mbar, 1K Pot = 1.54 K / 7±2 mbar.
1435	Measure short from qI Feedback to chassis: it's still 25 nS.
1440	While I (Matt) watched the short reading on the multimeter, Ruiren shoulder-bumped the cryostat from all four sides. When he bumped it from the East and West sides, I could see the reading drop briefly, to a few nS, then back. So, probably we need to warm up and open the fridge to fix this.
	We'll do one more transfer and cool back down to base. Then we can try moving the source, to see how much heating we get. Try to verify that we can move
1455	MB = 23.8%
1530	Begin LHe transfer
1540	Turn off MC heater. Tower temperature falls quickly.
1550	Tower = 2.05 K. 1K Pot = 1.52 K / 7.0 mbar.
1550	Open 1K Pot needle valve → 10°. 1K Pot → 1.52 K / 7.0 mbar.
1555	Open 1K Pot needle valve → 20°. 1K Pot → 1.58 K / 15.0 mbar. Open 1K Pot needle valve → 30°. 1K Pot → 1.61 K / 22 mbar.
1600	End LHe transfer
1602	MB = 93.9%
1610	Open 1K Pot needle valve → 40°. 1K Pot → 1.64 K / 28 mbar.
1613	MB = 91.2%
1615	Tower = 1.69 K, G1 (fridge) = 41 mbar. (3He pump is off.)
1645	Tower = 1.69 K, G1 (fridge) = 41 mbar. (3He pump is off.) 1K Pot = 1.64 K / 32 mbar.
1650	Turn on 3He pump
1705	Tower = 1.69 K, G1 (fridge) = 48 mbar. 1K Pot = 1.64 K / 30 mbar.
1710	Start circulation through Trap 2. V6 → 11.6%. We'll try this, although last time nothing happened until 12.8%.
1715	Adjust V6 upward in 0.4% steps once a minute. At V6 = 12.8% pressure starts to increase. Condenser peaks at 82 mbar. Tower → 1.67 K
1730	V6 → 13.0%. Condenser peaks at 136 mbar. Tower wavers a bit, → 1.67 K
1755	V6 → 13.2%. Condenser peaks at 270 mbar. Tower → 1.60 K
1830	V6 → 13.4%. Condenser peaks at 450 mbar. Tower → 1.52 K. Still → 150 mbar.
	Tower temperature keeps bouncing back up a little after each condenser peak. I know realize we left DCRC3 powered and connected. I should start MIDAS and turn off the 15V power.
1905	Start DAQ programs, then turn off 15V power on DCRC3.
1905	V6 → 13.6%. Condenser peaks at 564 mbar. Tower → 1.43 K. Still → 22 mbar.
1930	V6 → 13.8%. Condenser peaks at 630 mbar (pretty high). Tower → 1.36 K. Still → 10 mbar.
2025	V6 → 14.0%. Condenser peaks at 657 mbar. Tower → 1.32 K. Still → 5 mbar.
2045	Condenser = 558 mbar. Tower = 1.22 K. Still = 3.4 mbar.
2045	V6 → 14.3%. Condenser still falling, → 527 mbar. Tower → 1.14 K. Still → 2.0 mbar.
2055	V6 → 15.0%. Condenser peaks at 526 mbar. Tower → 1.05 K. Still → 0.95 mbar.
2115	V6 → 16.0%. Condenser peaks at 548 mbar. Tower → 0.88 K. Still → 0.50 mbar.
2150	V6 → 18.0%. Condenser peaks at 557 mbar. Tower → 0.83 K. Still → 0.34 mbar.
2210	V6 → 24.0%. Condenser peaks at 565 mbar. Tower → 0.74 K. Still → 0.24 mbar.
2230	V6 → 100.%. Condenser peaks at 567 mbar. Tower → 0.68 K. Still → 0.19 mbar.

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