2022/12/06 (Tuesday)
- Lab in-personnel: Matt
| Status | Run 76 in progress |
|---|---|
| Setup | Cables 2/3/1 → diverter/nothing/nothing → Side1-readout HV CONN 1/3/2 → HV 1(L)/2(R) → DCRC55(1)/DCRC50(3), 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 W side of fridge. NaI array undergoing scan, trigger threshold varies. |
| Cooled to base yesterday after thirtieth 5K pumpout. Temperature spikes began around 2:00 am. | |
| 1340 | MC/Coldplate = 30.2/146 mK, Still = 1.04 K / 0.080 mbar / 0 mW, G1/G2 = 190/176 mbar, 1K Pot = 45° / 1.59 K / 9.0±1.0 mbar, MB = 66.8% |
| 1345 | Fill LN2 cold trap bath |
| 1350 | Try powering DCRC1 and turning on DAQ programs. Like yesterday there's an initial MC spike to 61 mK, then it starts cooling. Channels B and C ok (have noise traces), Channel A railed like yesterday. |
| 1400 | Unplug DCRC1 from HV1 and try DCRC3 instead. Reset phonon settings appropriate for HV1. No heating but same behavior in the channels - B and C have noise traces, A railed. |
| 1410 | Try plugging DCRC2 directly into Cable 2 instead of through box. Again, B and C show traces, A railed. Has Cable2pA(Side1pE) been damaged? Note - would be better if I could zap, haven't figured that out yet. |
| 1425 | Try again to ZAP DCRC3 phonon channels, using the same ODB sequence that shows up in /MidasDAQ/online/sequencer/testzap.msl when you try to use the browser tool, which doesn't work. I think it worked this time - there were peaks in the Still pressure. |
| 1505 | Plug DCRC3 into Cable 1 to check Cable1pC(Side1pC) and Cable1pD(Side1pF). Both railed. Try zapping - again it looks like it worked, pressure spikes in still. Channels still railed. |
| So: maybe most of the Side1 channels were damaged (at SQUID or at QET) from the HV surge a few months ago. Only good ones are Side1pB and Side1pD (and couldn't actually get pulses in them). I guess actually the railing suggests problems at SQUID, not QET. | |
| 1335 | Remove HV box. Disassemble box, remove Side1-readout board, install Side2-readout board, reassemble box. Plug HV input and test resistor leads into HV box. Reconnect cables and DCRCs as before: Cables 2/3/1 → diverter/nothing/nothing → Side2-readout HV CONN 1/3/2 → HV 1(L)/2(R) → DCRC50(3)/DCRC55(1) Look up phonon settings on /data/chocula/k100/midasraw/livedata/run47984.odb which from the last data series on Dec 3, enter these in ODB for DCRC1&3. |
| 1550 | Power DCRCs1&3 and turn on DAQ programs. All phonon channels look ok except DCRC3pB which can't be unrailed. (I think that's Side2pA.) |
| 1555 | Turn off DAQ programs, power down DCRCs, reset connections for DCRC3 and Cable 3, power up and check phonon channels again. Now they are all OK. good. |
| 1615 | Adjust offsets to get all phonon baselines near -0.800 V |
| 1655 | Set NaI trigger window to 4.73-5.13 MeV |
| 1700 | Remove PuBe source from lab, put in in PAN 443B storage |
| 1719 | Dial HV up to -108.1V nominal, -106.0 V actual, for 15% prebias (using RootSequencer) |
| 1725 | Dial HV down to -94V nominal, -91.7V actual. Leakage is slightly higher than I'd like but I'll leave it. |
| 1730 | HV = -91.7 V, Vtest = -22 mV, Ileak = -24.2 uA, Vdet = -82 V (89%). |
| 1735 | DCRC1pA baseline = -0.795 V |
| check phonon channels, had to relock DCRC3pA&D | |
| 1738 | Start -82.0 V bg data series ## min long, SiHV-triggered with 1000 initial randoms, 5 Hz in-run randoms, trigger on DCRC1pB threshold 10. Start series with the Start Button |
| Actually I had DCR4pA trigger on too. So there will be some random-ish triggers in this series. | |
| 1858 | Start -82.1 V bg data series ## min long, NaI-triggered with 1000 initial randoms, 5 Hz in-run randoms, trigger on DCRC4pA threshold 20. Start series with the Start Button |
| 1900 | HV = -91.7 V, Vtest = -21.8 mV, Ileak = -24 uA, Vdet = -82.1 V (90%). |