2021/08/26 (Thursday)

Status	Run 74 in progress. First cooldown after IVC rebuild.
	Tower thermometer is reading high, probably this is a thermometer problem and the actual temperature is much lower. High noise in some of the charge channels.
	Setup: DIB1/2+acc → SL 41/43 → 3.2 MHz filters → cables 2/3 → nothing/Source_mover_board+HV_diverter_board → DCRC50(3)/55(1). Kepco 40V supplye → HV BNC. Lead shield erected, 4 walls. Currently both DCRCs are on.
	Position of Am source: y = 0.0 mm
0937	Tower/MC/Coldplate = 168.4/36.2/190.9 mK, Still = 1.38 K / 0.075 mbar / 0 mW, G1/G2= 297.5/267.3 mbar, 1K Pot = 1.58 K / 20±1 mbar. MB = 32.4%.
0941	Fill LN2 cold bath.
0956	At 10kHz noise in DCRC3qI/qO/DCRC1qI/qO = 22/4.7/2.5/83 8e-6. This is q3/q1/q4/q2 At 3kHz (peak) noise in DCRC3qI/qO/DCRC1qI/qO = 640/41/58/1100e-6
	Noise has been almost the same as yesterday
1004	Start 45 min series of 0V/-14,-13 0/-6V (initial bias applied after 60 sec, breakdown seen, reduced to -13 after one minute, change to -6 at 4 min), with Na-22 source at 80 cm, with 1000 beginning randoms, trigger threshold 120/60/45/260 on DCRC3qI/qO/DCRC1qI/qO, 5Hz in-run randoms, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). Start sequence with Start button.
1050	Dial HV down to 0V and flash detector for 10 minutes with DCRC1&3 LEDs.

Series 07210826_1004 bias -14 V at 60 seconds, saw breakdown and adjusted to -13 V, then change to -6 V at 4 minutes.

1335	Start 45 min series of 0V/-12 0/-8 0/-6V (started at -12V then bias applied after 120 sec and then 10 minutes later went down to -6V), with Na-22 source at 80 cm, with 1000 beginning randoms, trigger threshold 100/40/40/270 on DCRC3qI/qO/DCRC1qI/qO, 5Hz in-run randoms, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). Start sequence with Start button.
1427	Dial HV down to 0V and flash detector for 20 minutes with DCRC1&3 LEDs.
1456	Begin LHe transfer @ MB = 23.6 %
1529	End LHe transfer @ MB = 90.4 %
1540	Breakdown test. Start data and look at random triggers. Increase bias on Side 2 from 0/0V to 0/-18V, dialing up slow and steady (reached max in about 2 minutes). At 0/-18V breakdown noise was seen. Dial bias back down, after about a minute reach 0/-15.5V. At that point breakdown noise disappears.
1544	Dial HV down to 0V and flash detector for 10 minutes with DCRC1&3 LEDs.
1622	Start 45 min series of 0V/-10V, -6V (bias applied after 60 sec and then wait 11 min later went down at -6V), with Na-22 source at 80 cm, with 1000 beginning randoms, trigger threshold 70/40/40/200 on DCRC3qI/qO/DCRC1qI/qO, 5Hz in-run randoms, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). Start sequence with Start button.
1716	Dial HV down to 0V and flash detector for 10 minutes with DCRC1&3 LEDs.

Series 07210826_1335: A variety of biases started high and decreasing over the course of the run.

NOTE: initial bias was not @ 60 sec, it was actually 1min25 seconds before the randoms ended.

Series 07210826_1622: Starting at -10 V and reducing it to -6 V 11 minutes after.