2022/09/12 (Monday)
- Lab in-personnel: 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. |
| NaI trigger window: 7.6-11.2 MeV | |
| Warmed up yesterday, Sixth 5K pumpout. | |
| 1136 | MC = 5.70K, MB = 37.5% |
| 1137 | Fill LN2 cold trap bath |
| LN2 dewar ran out, will need to be refilled | |
| 1139 | Turbo on IVC = 1.4 nbar. With Turbo valved out for 1 minute IVC = 12 nbar. |
| 1141 | Close IVC valves on top of fridge |
| 1145 | Turn on 4He pump. Open Recovery valve to 4He pump. Pump out line to 1K pot (speedivalve closed).Check pressure in 1K Pot (with V4a open, 4He pump inlet valve closed). 1K Pot = 0.23 bar on mechanical gauge. |
| 1150 | Pump out 1K Pot in stages, alternating 1K Pot Speedivalve and V4a, opening V4a in brief spurts to keep 4He pump pressure low (below 5 mbar). |
| 1200 | Start pumping 1K Pot continuously |
| 1200 | MC = 5.68 K, cooling slowly. 1K Pot = 3.39 K / 2.0 mbar, cooling slowly |
| 1210 | Open 1K Pot needle valve → 15°. 1K Pot → 3.04 K / 6.5 mbar |
| 1220 | Open 1K Pot needle valve → 30°. 1K Pot → 2.79 K / 9.0 mbar |
| 1225 | Open 1K Pot needle valve → 45°. 1K Pot → 2.46 K / 13 mbar |
| 1225 | G1/G2 = 383/356 mbar |
| 1230 | Take LN2 dewar to be filled |
| 1250 | MC/1KPot = 2.87/2.00 and dropping linearly |
| 1345 | Finish filling LN2 cold trap dewar |
| 1346 | MC/1KPot = 1.96/1.53, G1/G2 = 47.8/47.2 mbar |
| 1410 | Begin LHe transfer @ MB = 33.6% |
| 1419 | Close V3 and V9, leaving 59 mbar mixture in dump |
| 1419 | Turn on 3He pump |
| 1425 | Start circulation through Trap 1. V6 → 12.6%. Condenser peaks at 257 mbar. MC(H35) → 1.43 K. Still → 1.47 K / 32 mbar. |
| 1434 | V6 → 13.0%. Condenser(G1) peaks at 270 mbar. MC(H35) → 1.37 K. Still(P1) → 1.41 K / 16 mbar. |
| 1445 | V6 → 13.4%. Condenser(G1) peaks at 235 mbar. MC(H35) → 1.18 K. Still(P1) → 1.19 K / 4.5 mbar. |
| 1454 | Ended LHe transfer @ MB = 95.6% |
| 1457 | V6 → 13.8%. Condenser(G1) peaks at 193 mbar. MC(H35) → 0.87 K. Still(P1) → 1.12 K / 1.7 mbar. |
| 1505 | G1 still rising slowly, now at 197 |
| 1513 | V6 → 14.4%. Condenser(G1) peaks at 202 mbar. MC(H35) → 0.49 K. Still(P1) → 1.13 K / 0.95 mbar. |
| 1520 | V6 → 15.0%. Condenser(G1) peaks at 197 mbar. MC(H35) → 0.30 K. Still(P1) → 1.13 K / 0.55 mbar. |
| 1530 | V6 → 100%. Condenser(G1) peaks at 185 mbar. MC(H35) → 0.11 K. Still(P1) → 1.09 K / 0.13 mbar. |
| 1545 | MC = 54.5 mK, plug in DCRCs 1 and 3 |
| MC temp stalls for a minute then continues to drop | |
| 1632 | MC = 28.2 mK and pretty flat, Condenser = 136 and pretty flat. 1K Pot = 1.57 K / 12±1 mbar. |
| 1634 | Open V14 to pull the rest of the mixture out of the dump into circulation. (Accidentally opened V4 to dump for a second, didn't seem to cause any problems though) |
| MC rises to 66 mK, Still peaks above 30 mbar then falls again, Condenser rises to 232 mbar. 1K Pot unaffected. | |
| as usual we'll wait till Still is below 1 mbar then close V14. | |
| 1700 | Still = 0.6 mbar. close V14 |
| 1910 | Check phonon pulses - looking good, baselines all around -0.8 V |
| 1920 | MC = 28.3 mK |
| we'll try a higher bias again. Lately we haven't been able to go very high without significant current leakage Let's try -100V nominal, see how the leakage looks |
|
| 1924 | Dial HV up to -115V nominal, -112.9V actual, for 15% prebias, using RootSequencer |
| Vtest fell as low as -16 mV but then after a little under 5 minutes suddenly rose to a new plateau, same as last few times I've tried | |
| 1932 | Dial HV down to -100V nominal, -97.9V actual |
| 1935 | HV = -97.8 V, Vtest = -28.4 mV, Ileak = -31.3 uA, Vdet = -85.3 V (87%). Not quite as bad as last time (Aug 29) |
| 1942 | Dial HV down to -71V nominal, -68.8 V actual |
| 1952 | Vtest has settled HV = -68.8 V, Vtest = -4.4 mV, Ileak = -4.8 uA, Vdet = -66.8 V (97%). |
| 1955 | Pulses still look good |
| 1955 | Start -66.8 V PuBe data series 70 min long, SiHV-triggered, with 1000 initial randoms, 5 Hz in-run randoms, trigger on DCRC1pB threshold 10. Start series with the Start Button |
| 2107 | Start -66.8 V PuBe data series 657 min long, NaI-triggered, with 1000 initial randoms, 5 Hz in-run randoms, trigger on DCRC4pA threshold 20. Start series with the Start Button |
| 2110 | HV = -68.8 V, Vtest = -4.3 mV, Ileak = -4.8 uA, Vdet = -66.8 V (97%). |
| 2110 | MC = 28.6 mK |