2022/07/12 (Tuesday)
- Lab in-personnel: Matt, Giulia
| 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 source behind lead wall. NaI trigger window -t10760 -T15760 (7.6-11.2 MeV) |
| Taking 0V NaI-triggered data continuously | |
| 1016 | Start -197.3 V PuBe data series 28 min long, with 1000 initial randoms, 5 Hz in-run randoms, trigger on DCRC3pD threshold 10 (Si-triggered). Start series with the Start Button. |
| 1231 | MC/Coldplate = 28.9/155 mK, Still = 1.12 K / 0.095 mbar / 0 mW, G1/G2 = 101/102 mbar, 1K Pot = 60° / 1.55 K / 8.0±0.5 mbar, MB = 72.7% |
| 1240 | Filled LN2 cold trap bath |
| Let's take another HV-varying data series, dial HV down to zero slowly. | |
| 1324 | Start -197.4 V PuBe data series 3 min long, with 1000 initial randoms, 5 Hz in-run randoms, trigger on DCRC3pD threshold 10 (Si-triggered). Start series with the Start Button. |
| BAD SERIES, see below | |
| 1325 | HV = -197.36 V, Vtest = -30.8 mV, MC = 29.2 mK |
| 1327 | Abort series because some phonon channels look bad. |
| 1335 | Relock several channels to get baselines back to normal (around -0.8). Had to adjust DCRC3pA offset from 0.55 to 0.35. 0.35 was a setting we used some time ago, not sure how long. |
| 1336 | Start varied-HV PuBe data series 213 min long, with 1000 initial randoms, 5 Hz in-run randoms, trigger on DCRC3pD threshold 10 (Si-triggered). Start series with the Start Button. |
| 1342 | 5 minutes into series, start stepping down voltage from -200V to 0V. Rather than the standard 5 V/s we'll do it more slowly, 0.5 V/s. |
| Watching both HV and Vtest to get true detector bias as function of time. It took about 7 minutes for the nominal HV to fall to zero, during which Vdetector fell to about -30V. Then HV essentially decayed exponentially with time constant 77s for a few minutes. Then it fell more slowly, reaching -4V at 10 minutes, -1V at 20 minutes, -0.5V at 60 minutes, -0.25V at 180 minutes. |