2020/10/21 (Wednesday)

Lab in-person: Matt & Ruiren
Virtual partner: Michael, later Ruiren & Pramod

Setup	Run 73. DIB 1/3/4 → Stripline 43/48/41 → pi-filters 1/2/3 → Cable 3/1/2 → nothing/nothing/accessory_interposer → HV_Conn 1/3/2 → HV 1/2 → DCRCX(4)/DCRC55(1)-master; DCRC33(2) → HV control. DCRCs on. Lead/poly shield erected (4 lead walls, 2 poly walls).
	The Kepco power supply that provided HV bias for the detector has died. We need to work on alternatives - try using a different supply for now, and shop for a replacement (or repair it).
0903	Tower = 36.0%
0945	Matt Fritts body temperature = 96.4 F
0945	Tower thermometer = 91.8 mK. It has been wandering between 76 and 102 mK. We now know that this is a thermometer problem, presumably caused by helium films, and that the detector temperature is significantly lower and more stable.
1140	Do IbIs on DCRC1pD. Implied detector temperature = 60.5 mK. Tower thermometer = 86.8-88.2 mK. This is consistent with the last few days Tower/Detector relationship.
1240	Matt enters lab
1245	Tower/MC/Coldplate = 88.4/30.7/196 mK, Still = 1.50 K / 0.130 mbar / 0 mW, G1/G2= 244/220 mbar, 1K Pot = 1.62 K / 21±2 mbar.
	I'll leave the switchbox on the MC thermometer (RuO2 H35) for now.
1310	MC(H35) is staying very close to 30.7 mK, varying by about ±0.05 mK.
1325	MC(H35) was around 30.67, then rose to 30.73 and stayed there a while, then rose to 30.81 and stayed there a while. The wandering is similar to what the Tower thermometer does, although on a smaller scale. Hard to say whether they are tracking the same temperature variations; we'd have to switch back and forth between thermometers to verify.
1355	Connect Kepco 40V power supply to HV. We don't have remote control set up for this power supply. Let's try taking drifted bias data, drifting the bias manually.
1403	Start a 16 min series at HV = +10V, drifting 0.0220 V/s, no prebias, CDMS detector: Driver Gains = 1x, DCRC4/1 QET biases = set for 60.4 mK, Front-End Gains = (3/3/3)/(5/5/5) 1000 BOR & 5 Hz in-run randoms, trigger on DCRC1pD threshold = 8 Drifting manually, no sequencer
1403	Vtest = 0.29 mV shortly after drift begins. Drift starts at 10.0 V. 1.2% HV loss.
	Tower wandered between 82 and 87 mK during series.
1419	Vtest = 0.31 V at end of drift. Final HV = +31 V. 0.4% HV loss.
1445	start lHe transfer at 27.6%
1500	Fill LN2 cold trap bath
1515	end lHe transfer @ MB = 89.1%
1535	MB = 89.2%
	The Kepco HV power supply came back to life! Sometimes when you dial it up it doesn't work, but then if dial back to zero and try again, it eventually works.
1555	Tried recalibrating the Kepco power supply. But changing DCRC2qI from 0 to anything else doesn't change anything. Stop DAQ programs, power down DCRC2, plug it into the minibob to troubleshoot.
1630	qI and qO are working according to the minibob, seeing the right outputs (or in the ballpark at least)
1700	Hook up DCRC2 remote circuit outputs to Kepco. With qI = 0 (or actually 0.253, which outputs 0V) dial HV up to 500V. Then modify DCRC2qI bias and read HV output to make a new calibration curve.

New HV calibration

1715	Enter the new calibration into the RootSequencer.
1715	Restart the DAQ programs. Note: Tower thermometer fell from 90 to 57 mK after 15:30, stayed there a while, stable. Then started warming at 17:10. It may have made sense that this happened if I'd turned off DCRC1&4, but I didn't - I just turned off the DAQ programs, and DCRC2 was off and on a few times (but that's not connected to anything cold). Tower thermometer is rising now.
1720	Zap SQUIDs.
1725	Connect HV power leads to HV box.
1730	Matt leaves lab

1900	Phonon channels all look good
1900	Tower thermometer wandering between 87.2 & 89.1 mK
1915	Do IbIs on DCRC1pD. Implied detector temperature = 61.2 mK. Tower thermometer varied between 88.3 and 88.9 mK. This is roughly consistent with previous pattern.
1936	Try to do a +300V drifted data series, but it looks like the power supply died again. Instead of bias going up 1V/s, it went down to about -0.1 V over a minute. Crap.
2300	Matt Fritts body temperature = 97.6 F

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