2022/08/01 (Monday)
- Lab in-personnel: Matt,Giulia,Zach
| 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. |
| Restarted circulation yesterday after a fridge failure (impedance blockage) a week ago. | |
| 1100 | MC(Cernox)/1K Pot = 28.8/1.7, G1(fridge) = 81.3 mbar. MB = 62.1% / 126 mbar+1atm |
| Fridge is sorta unstable. Overnight a couple times the circulation pressures fell from like 100 to 85 mbar, then rose and plateaued a while. Accompanied by Still pressure spike from 0.13 to around 0.2 mbar. Also accompanied by MC temperature spikes I think, one from 28.8 to 29.6 mK. | |
| 1125 | Fill LN2 cold trap bath |
| 1145 | Restart MIDAS and DAQ programs |
| 1150 | Zap SQUIDs pA,B,D on DCRC1&3 |
| 1235 | Look at phonon channels. None of them have any pulses. MC temperature is higher than before the flash - maybe the SQUIDs are in a bad state. |
| 1240 | Try another ZAP. No better. Temperature actually higher. |
| 1245 | Try powercycling the DCRCs. |
| Remembered after the fact that the PuBe source is still inside the lead/poly shield so the rate of events in the SiHV was super-high - that may explain why channels didn't look good (although it didn't really look like a pileup problem…) | |
| 1405 | Remove PuBe source from inside the lead/poly shield, put it back in the paraffin drum behind the lead wall on the West side |
| 1410 | Check phonon channels again. Now we see pulses. All the pulses in DCRC1 though are weak. Some baselines are still around -0.8 V, others are way off. Not sure whether we should expect the offsets to change after warming and recooling. (Also: are IbIs curves the same? Are SQUID-tuning parameters the same?) |
| SQUIDtuningGUI is acting pretty sluggish, hard to use | |
| 1420 | Zap SQUIDs in DCRCs1&3 |
| 1450 | Temperature is elevated, pulses don't look great (and SQUIDtuningGUI is sluggish) so turn off DAQ programs and unplug DCRCs again. |
| 1520 | Begin LHe transfer @ MB = 55.7% |
| 1558 | End LHe transfer @ MB = 92.6% |
| 1900 | Just remembered I forgot the final stage of cooling to base yesterday: I never opened V14 to pull the remaining mixture out of the dump into circulation. Let's do that now. |
| 1905 | Open V14 to let the remaining mix out of the dump and into circulation. P1(Still) peaks at about 45 mbar then falls again. MC(H35) peaks twice, at 65 then at 68 mK. Condenser peaks at 180 mbar. |
| 1930 | Still = 0.80 mbar. Close V14. |
| 2100 | MC(H35)/Coldplate = 28.9/146 mK. Still(P1) = 1.13 K / 0.13 mbar. G1/G2 = 124/125 mbar. |