2019/08/01 (Thursday)
| 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 NaI B → DCRC50(3) pB Lead/poly shield erected, south wall partial lead only (with NaI detectors). |
|---|---|
| PuBe source in lab behind lead stack. | |
| 1110 | Tower/MC/Coldplate = 39.6/30.0/200 mK, Still = 1.33 K/ 0.095 mbar / 0 mW, G1/G2= 120/109 mbar, 1K Pot = 1.68 K / 40 mbar. MB= 27.6% |
| 1110 | Fill LN2 Coldtrap Bath |
| 1140 | Notice a problem with recent series, beginning at 0731_1556 and continuing to most recent, 0801_0826 - pF shows no line in the Data Quality plots. Also noticing that the leakage shown on Vtest is high recently, peaking around 17 mV, previously I think it was peaking around 8 mV. This shouldn't come close to killing the Luke gain, so maybe it's an unrelated issue (but it needs to be investigated too). Looking at BatViewer it looks like the problem is that pF is nearly (but not totally) railed. |
| 1155 | The rubber hose from the LN2 Dewar vent had been knocked out of the Ebox purge bag, probably during LHe transfer. I rerouted the hose so it's less likely to get knocked around and reinserted it into the purge bag. The relatively high leakage began with the series started yesterday around 23:30. |
| 1210 | Adjust DCRC1pD (Side1pF) driver offset to unrail it. All other channels look OK. |
| 1310 | Begin LHe transfer MB = 24.7% |
| 1348 | Finish LHe transfer MB = 91.4% |
| 1359 | Start a sequence of 8 @ 34 min series at HV = 180→327V, rate 4.31V/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, baseline/sample length = 120/28 (standard 16/5), phonon pre-pulse 500 (standard is 500). NaI detector: 800 V → NaI B (dynode terminated) → PS776 → Lecroy 628 Fan In/Out → Ortec 452(Neg input, G=100, shaping=6us, -10V output) → DCRC3 PB, Driver Gains = 1, PhononWaveFormLength = 1024 (512 samples), PhononPrepulseSamples = 512 (512 samples) Use sequence HVdrift_8X180V_4p31VPM_loopversion_prebias_10_2_dur_34min_flashDCRC_1_4.msl |
| 1527 | MIDAS mhttpd crashed again, restart it. Sequence was right at the end of the post-flash wait period, so should be fine. |
| 1625 | Fill LN2 cold trap bath. |