2022/05/31 (Tuesday)
- Lab in-personnel: Matt, 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) |
| NaI trigger configuration: detectors 10,11,12, threshold range 1300-2100 | |
| 0800 | MC/Coldplate = 29.6/145 mK, Still = 0.100 mbar / 0 mW, G1/G2 = 196/195 mbar, 1K Pot = 18° / 1.55 K / 7.5±0.5 mbar |
| Since yesterday's transfer the MC temperature and the circulation pressures are very high compared to normal during this run. Looked at the phonon channels - they all look OK actually. So it doesn't seem like a problem related to the DCRCs, SQUIDs. The 1K Pot temperature and pressure have been drifting lower and lower. Still seems to be running ok but maybe now it's below some threshold where it's not cooling the returning mixture adequately.(?) |
|
| 0810 | Start 0 V data series 66 min long, with 1000 initial randoms, 5 Hz in-run randoms, trigger on DCRC3pD threshold 10. Start series with the Start Button. |
| note: unlike previous data, DCRC4 is enabled. This will be a first look for coincident NaI triggers in S104-triggered events, with no external source present. | |
| 1210 | Place Na-22 source on the North side of the fridge, level with the detector in a lead castle. Try different distances from the mu-metal shield, count pulses in traces to get rate in S104: no-source/65/48/32/20 cm = 64/69/85/160/171 Hz. We'll try 48 cm. That's about 21 Hz in excess of background, and pileup rate is less than 25%. |
| 1214 | Start 0 V Na-22 data series 78 min long, source 48cm from mu-metal shield, with 1000 initial randoms, 5 Hz in-run randoms, trigger on DCRC3pD threshold 10. Start series with the Start Button. |
| 1430 | Fill LN2 cold trap bath |
| MC temperature started falling around 12:00 and was nearly back to normal by 14:30, but then after the LN2 transfer it popped back up, → 29.4 mK. But as of 15:45 it's starting to fall again. G1/G2 have been falling but they're still higher than normal. | |
| 1630 | MC/Coldplate = 29.1/145 mK, Still = 1.08 K / 0.100 mbar / 0 mW, G1/G2 = 176/171 mbar, 1K Pot = 18° / 1.55 K / 7.5±0.5 mbar, MB = 66.2% |
| 1635 | Look at 1K Pot needle valve. Looks like it's around 40°, even though I've been writing 18° every day. |
| 1635 | Open 1K Pot needle valve wider, 40° → 45°. 1K Pot T&P rise a little, → 1.5 K / 9.5 mbar |