2022/07/25 (Monday)
- 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 behind lead wall on West side of lead/poly shield. |
| 1105 | MC/Coldplate = 29.3/156 mK, Still = 1.13 K / 0.100 mbar / 0 mW, G1/G2 = 126/118 mbar, 1K Pot = 60° / 1.52 K / 7.25±0.25 mbar, MB = 42.6% |
| 1116 | Fill LN2 cold trap bath |
| 1410 | Look at phonon channels. Had to relock most of them to get them to their ~-0.8 baselines. Had to adjust DCRC3pA offset from 0.35 to 0.55 again, we've been switching back and forth occasionally. |
| 1529 | Begin LHe transfer @ MB = 36.4% |
| 1550 | After starting transfer, noticed MC temperature is rising steadily, and G1/G2 are rising linearly, much more than normal. 1K Pot dipped at beginning of transfer, maybe it's too low? |
| 1555 | Open 1K Pot valve more, 60° → 70° |
| 1555 | Noticed that Still pressure dropped at around 15:30, from 0.110 to 0.036 mbar. That's bad. Blockage?? |
| 1600 | Turn on Still heater → 5.0 mW |
| Still pressure rose to 0.120 mbar after turning on heater. MC had risen all the way to 42 mK but started falling quickly after turning on Still heater. G1 had risen to 240 mbar, after turning on heater it started rising faster | |
| 1604 | G1 = 330 mbar and rising. MC = 33 mK and falling. |
| 1606 | MC fell to 32.5 mK but then started rising quickly. G1 continues to climb, can't let this go on too long… |
| 1608 | Turn off Still heater again. Still pressure drops to 0.036 mbar again. Also notice Still temperature falls, 0.97 K. Turn heater back on to 5.0 mW. Still → 1.12 K / 0.110 mbar |
| 1612 | MC climbing higher than before, 48 mK and still rising. G1 rose more slowly when Still heater was off, now rising quickly again, 450 mbar. |
| 1615 | Stop DAQ programs then unplug DCRC1&3 |
| 1618 | End LHe transfer @ MB = 97.4% |
| 1623 | MC = 71 mK and rising. G1 = 612 mbar and rising. |
| 1624 | Close V6, we need to stop circulation. |
| 1630 | V6 is completely closed. Still pressure 3.0 mbar and rising. G1 has stopped increasing, now flat. Mixture should be able to expand into Still side now, so G1 should fall - unless there's an impedance blockage… |
| 1632 | G1 falling very slowly, something like 0.4 mbar/min |
| 1635 | Turn off Still heater |
| 1645 | G1 = 654 mbar, falling at 0.34 mbar/min. Looks like a blockage :( |