2021/08/31 (Tuesday)

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
0843	Tower/MC/Coldplate = 143.9/35.6/191.5 mK, Still = 1.39 K / 0.070 mbar / 0 mW, G1/G2= 285/264 mbar, 1K Pot = 1.57 K / 10±1 mbar. MB = 73.6%.
0853	Fill LN2 cold trap bath.
0856	At 10kHz noise in DCRC3qI/qO/DCRC1qI/qO = 19/4.0/2.8/75 8e-6. This is q3/q1/q4/q2 At 3kHz (peak) noise in DCRC3qI/qO/DCRC1qI/qO = 470/46/50/81 e-6
	Noise is considerably higher than yesterday.
0941	Start 45 min series of +10V/0V, +9V/0V, +8V/0V, +7V/0V (initial bias applied after 60 sec, then 90 sec pauses to 9V, 8V, 7V), with 1000 beginning randoms, trigger threshold 120/40/40/400 on DCRC3qI/qO/DCRC1qI/qO, ~~5Hz in-run randoms~~, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). Use Sequencer script r74_takeandflash_dcrcbias.msl. This flashes for 30 seconds at end of series. Reset bias using the Tools interface - this isn't very fast, took several seconds to change all 4 channels.

07210831_0941

	Let's try heating the fridge again as on Aug 19. That time we wound up increasing the impact ionization strength at elevated temperature, then cooled again and saw the same increase (i.e. the heating seemed to induce a state change).
1225	Tower/MC = 162.5/ 35.1 mK
1225	Turn MC heater on to 600 μW
1320	Tower/MC = 0.871/0.884 K and seem to have settled. G1/G2 = 381/352 mbar, Still = 0.130 mbar.
1335	Start 45 min series of +10V/0V (bias applied after 60 sec), at elevated temperature, with 1000 beginning randoms, trigger threshold 150/70/40/400 on DCRC3qI/qO/DCRC1qI/qO, 5Hz in-run randoms, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). Use Sequencer script r74_takeandflash_dcrcbias.msl. This flashes for 30 seconds at end of series.
1445	Turn off MC heater
	THIS LAST DATA SERIES DIDN'T WRITE! dammit MIDAS!
	well… we can do another 10V series after it cools to base, and see if the stat has changed.
1545	Tower = 180 mK, seems to be pretty flat now. MC = 36.1 mK
1553	Start 45 min series of +10V/0V (bias applied after 60 sec), with 1000 beginning randoms, trigger threshold 120/50/40/450 on DCRC3qI/qO/DCRC1qI/qO, 5Hz in-run randoms, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). Use Sequencer script r74_takeandflash_dcrcbias.msl. This flashes for 30 seconds at end of series.