2019/07/02 (Tuesday)
| Setup | DIB1/3/4 → 3.2 MHz filters 2/3/1 → cable 3/1/2 → gender changer ?/3/2 → HVConn 1/3/2 → HV 1/2 → DCRCX(4)/DCRC55(1) DCRC33(2) → 1kV power supply → HV input Three walls of the lead/poly shield are up. |
|---|---|
| 0925 | Fill LN2 cold trap bath-started filling, then seemed to stop after a few minutes. Will attempt to fill again shortly. |
| 0935 | Tower/MC/Coldplate = 38.7/29.4/199 mK, Still = 1.38 K / 0.18 mbar / 6 mW, G1/G2 = 214.1/206.9 mbar, 1K Pot = 1.619 K / 19 mbar. MB = 35.4% |
| 1200 | Looking at the weekend data, still can't see 0.16 keV M-shell activation peak. Looking at pulses, I think our trigger window is far from optimal. We have PhononTriggerSampleLength set to 5. A typical pulse is much wider than this. Experiment with setting it wider, to 40. It looks like this does not affect the start time of pulses, so that's good. Let's take some data like this. Actually no - an error is thrown, saying that the maximum SampleLength is 31. Let's try 30 instead. Note: it looks like you have to stop and restart the run when you want to try a new SampleLength, otherwise it starts triggering constantly. Looking more closely, it seems that when I change BaselineLength/SampleLength from 16/5 to 20/30, it makes the pulses appear earlier in the trace. That will throw off the timing for OF. To compensate, I'm also changing the phonon prepulse from 500 to 600. Now it looks like they show up close to the normal place. |
| 1420 | Begin LHe Transfer, MB = 28.6% |
| 1505 | End LHe Transfer, MB = 90.2% |
| 1600 | Fill LN2 ColdTrap Bath. Took a long time to fill up but did fill up |
| 1612 | Start a sequence of 6 @ 87 min series at HV = 180→400V, rate 2.49V/min, with 10% prebias for 2 minutes, flash at end with 30 min wait. CDMS detector: Driver Gains = 1x, DCRC4/1 QET biases = (490/400/495)/(420/480/450) uA, Front-End Gains = (2/2/3)/(5/5/5) 1000 BOR, 5Hz InRun randoms, trigger on DCRC1pD threshold = 6,6,5,5,5,5, baseline/sample length = 20/30 (standard 5/16), phonon pre-pulse 600 (standard is 500). Use sequence HVdrift_6X180V_2p49VPM_loopversion_prebias_10_2_dur_87min_flashDCRC_1_4.msl |
| Note: we should also try a lower trigger threshold with these new trigger lengths, see if that works OK. | |
| 1700 | DCRC1pB is railed - it happened during Dump 27 of the first series above. |
| 1705 | Unrail DCRC1pB and adjust some other driver offsets, 43 minutes into the first series. |
| 2030 | Reset the trigger threshold from 6→5 after the second sequence finishes. |
- Analysis of above data suggests that the trigger threshold is far above the noise - maybe 600 eVee even for the lower trig threshold of 5. So we should try a lower threshold.