2021/08/17 (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. No lead/poly shield. Currently both DCRCs are on.
	Position of Am source: y = 0.00 mm
0901	Tower/MC/Coldplate = 202.8/36.1/192.5 mK, Still = 1.39 K / 0.075 mbar / 0 mW, G1/G2= 292.6/270.2 mbar, 1K Pot = 1.59 K / 20±1 mbar. MB = 70.8%.
0909	Fill LN2 cold bath.
0910	At 10kHz noise in DCRC3qI/qO/DCRC1qI/qO = 35/4.7/3.7/90 8e-6. This is q3/q1/q4/q2 At 3kHz (peak) noise in DCRC3qI/qO/DCRC1qI/qO = 940/92/74/1100e-6
	Noise is considerably higher than yesterday.
1043	Start data then abort after randoms, overtriggering
1047	Start 45 min series of 0V/-12V (bias applied after 60 sec), with 1000 beginning randoms, trigger threshold 120/60/65/300 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.
1135	Dial HV down to 0V and flash for 10 minutes with DCRC1&3 LEDs.

07210817_1047. Detector is still in a strong impact ionization “state”. This peaks even higher than 12V did on Friday
and yet 9V is weak.

	we'll try 0V/-10V
1215	Start 47 min series of 0V/-10V (bias applied after 60 sec), with 1000 beginning randoms, trigger threshold 120/50/70/280 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.
1304	Dial bias down to 0V and flash for 10 minutes with DCRC1&3 LEDs.

07210817_1215. 10V seems like a nice standard to start from in the current detector state.

	Let's move near the blocker, to see if a lower rate of Am events changes the impact ionization pattern.
1329	Do mvNwait -4steps×69 times, 40 second wait, with dwell = 40 and power = 6.8 V. (Around 5.93 mm/hour) This sequence will take 46min0sec and will move the source a total distance of 4.55 mm. Should end at 2:15 pm. Mean Tower temperature settles around 1.80 K during move.
1415	Move sequence ends, pretty much on time.
	Position of Am source: y = -4.55 mm. The edge of the blocker should be at -4.59 mm. I expect this to block roughly 50% of the Am-241 events.
1527	Start 45 min series of 0V/-10V (bias applied after 60 sec), Am source y= -4.55 mm, with 1000 beginning randoms, trigger threshold 50/40/60/90 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.
1612	Dial HV down to 0V and flash for 10 minutes with DCRC1&3 LEDs.

07210817_1527. Looks like with reduced 60keV rate, the impact ionization is pretty much the same
although the falloff after the peak seems slower

	Let's move further over the blocker. We'll move about 1 sigma of the source spread, which is around 0.47 mm according to sim.
1642	Do mvNwait -4steps×7 times, 40 second wait, with dwell = 40 and power = 6.8 V. (Around 5.93 mm/hour) This sequence will take 4min40sec and will move the source a total distance of 0.46 mm. Mean Tower temperature peaks around 1.70 K during move.
1647	Move sequence ends.
1747	Start 45 min series of 0V/-10V (bias applied after 60 sec), with 1000 beginning randoms, trigger threshold 70/80/70/90 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.
1832	Dial HV down to 0V and flash for 10 minutes with DCRC1&3 LEDs.

07210817_1747