2022/08/18 (Thursday)
- Lab in-personnel: Giulia, Himangshu, Matt
| Status | Run 76 in progress |
|---|---|
| Setup | Cables 2/3/1 → diverter/nothing/nothing → Side2-readout HV CONN 1/3/2 → HV 1(L)/2(R) → DCRC50(3)/DCRC55(1), DCRC33(2)→HV control, NaI trigger signal → DCRCX(4) Lead/poly shield fully assembled. Boron-filled socks covering NaI detectors. PuBe behind lead wall on West side of lead/poly shield. |
| 0930 | No spikes in MC temperature overnight. Currently 28.6 mK |
| 0930 | Phonon channels all look good. Somewhat lower baselines compared to yesterday. |
| 0935 | Dial HV up to -230V nominal for 15% prebias (using RootSequencer) |
| 0940 | Dial HV down to -200V nominal, -198.4V actual |
| 0945 | Vtest is very high, -242 mV, implying -266 nA leakage and Vdetector only -91.8 V (46% of HV). Should check the E-box purge in the lab. Abort for now. |
| 0945 | Dial HV back down to 0V |
| 1057 | MC/Coldplate = 28.6/149 mK, Still = 1.12 K / 0.120 mbar / 0 mW, G1/G2 = 147/142 mbar, 1K Pot = 50° / 1.62 K / 19±1 mbar, MB = 73.9% |
| 1108 | Fill LN2 cold trap bath |
| 1240 | Increase flow from LN2 vent to E-box purge a little. Try biasing to -17.6V. After a few minutes Vtest = -3.5 mV, so Vdet = 91% HV, not bad. |
| 1245 | Dial HV up to -47.7 V. After a few minutes Vtest = -9.6 V, so 90%, also not bad. |
| 1255 | Dial HV up to -97.9 V. Vtest relaxed to -20 mV, then rose and plateaued at -25.6 mV. That's -28 nA leakage, and Vdet is only 88% of HV. Not too good. And worrying… has something maybe changed with the detector since the mishap on Monday, when the DAQ glitched caused a sudden very high voltage on the detector. |
| 1300 | Dial HV back down to 0V |