2022/08/29 (Monday)
- 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) Lead/poly shield fully assembled. Boron-filled socks covering NaI detectors. PuBe behind lead wall on West side of lead/poly shield. |
| 3rd 5K pumpout yesterday. IVC has been pumping out overnight. | |
| 0930 | MC/1KPot/Sorb = 6.01/6.98/8.9 K |
| 0950 | Turbo on IVC = 1.4 nbar. With Turbo valved out for 1 minute IVC = 12 nbar. |
| 0955 | Turn on 4He pump. Open Recovery valve to 4He pump. Check pressure in 1K Pot (with V4a open, 4He pump inlet valve closed). 1K Pot = 0.23 bar on mechanical gauge. |
| 0955 | Pump out 1K Pot in stages, alternating 1K Pot Speedivalve and V4a, opening V4a in brief spurts to keep 4He pump pressure low. |
| 1000 | Start pumping 1K Pot continuously |
| MC and 1K Pot cooling | |
| 1045 | MC = 3.42 K, cooling slowly. 1K Pot = 3.27 K / 1.7 mbar, cooling slowly |
| 1045 | Open 1K Pot needle valve → 15°. 1K Pot → 2.95 K / 5.5 mbar |
| 1050 | Open 1K Pot needle valve → 30°. 1K Pot → 2.65 K / 10 mbar |
| 1105 | Open 1K Pot needle valve → 45°. 1K Pot → 2.24 K / 15 mbar |
| 1110 | MC/Sorb = 2.95/4.0 K. G1(Fridge+Dump) = 240 mbar and falling. |
| 1255 | MC = 1.80 K. G1(Fridge+Dump) = 41 mbar and falling. 1K Pot = 1.61 K / 15+-1 mbar |
| 1410 | MC = 1.76 K. G1(Fridge+Dump) = 36 mbar and falling. 1K Pot = 1.60 K / 15+-1 mbar |
| 1410 | Turn on 3He pump |
| 1420 | Fill LN2 cold trap bath (a bit overdue maybe) |
| 1440 | Close V3 and V9, leaving 40 mbar mixture in dump |
| 1435 | Start circulation through Trap 1. V6 → 12.6%. Condenser peaks at 229 mbar. MC(H35) → 1.46 K. Still → 1.51 K / 60 mbar. |
| 1445 | V6 → 13.0%. Condenser(G1) peaks at 319 mbar. MC(H35) → 1.34 K. Still(P1) → 1.38 K / 12 mbar. |
| 1500 | V6 → 13.4%. Condenser(G1) peaks at 283 mbar. MC(H35) → 1.15 K, bouncing around a bit. Still(P1) → 1.20 K / 3.6 mbar. |
| MC hanging around 1.17 K | |
| 1510 | V6 → 13.8%. Condenser(G1) peaks at 227 mbar. MC(H35) → 1.08 K, looks like we got past the Al transition. Still(P1) → 1.20 K / 3.2 mbar. |
| 1520 | V6 → 14.4%. Condenser(G1) peaks at 244 mbar. MC(H35) → 0.44 K. Still(P1) → 1.17 K / 1.3 mbar. |
| 1535 | V6 → 15.0%. Condenser(G1) peaks at 231 mbar. MC(H35) → 0.21 K. Still(P1) → 1.17 K / 0.5 mbar. |
| 1550 | V6 → 100%. Condenser(G1) peaks at 216 mbar. MC(H35) → 76 mK. Still(P1) → 1.13 K / 0.11 mbar. |
| 1600 | Open V14 to pull the remaining mixture out of the Dump and into circulation |
| Condenser peaks at 245 mbar then falls again. MC rises to 95 mK then falls again. 1K Pot rises too. | |
| 1613 | Begin LHe transfer @ MB = 35.5% |
| 1620 | MC/Coldplate = 37.6/149 mK, Still = 1.11 K / 1.10 mbar, 1K Pot = 1.66 K / 31±2 mbar |
| 1635 | MC/Coldplate = 29.7/146 mK, Still = 1.10 K / 0.5 mbar, 1K Pot = 1.58 K / 15±2 mbar |
| 1635 | Close V14 |
| 1703 | Ended LHe transfer @ MB = 91.9% |
| 1715 | MC/Coldplate = 27.5/145 mK, Still = 1.10 K / 0.075 mbar, 1K Pot = 1.58 K / 15±2 mbar |
| 1720 | Open LN2 Dewar vent to very low flow rate, connect to E-box purge bag |
| 1745 | Power DCRCs 1&3 and turn on DAQ programs. Enable DCRCs 1,2,3 so that we can watch traces while adjusting HV. |
| 1750 | Set QET biases to Aug 25 values, after the last 5K pumpout. Pulses look pretty good in all channels. |
| 1805 | Adjust offsets to get all baselines near -0.80 V |
| 1925 | MC has settled at 28.6 mK after turning on DCRCs |
| Let's try -100V nominal, see how the leakage looks | |
| 1939 | Dial HV up to -115V nominal, -112.9V actual, for 15% prebias, using RootSequencer |
| Vtest falls for about 4 minutes, then rises to a new plateau - looks about like it did the last time. | |
| 1945 | Dial HV down to -100V nominal, -97.9V actual |
| 1955 | HV = -97.9 V, Vtest = -31.5 mV, Ileak = -34.7 uA, Vdet = -84 V (86%). |
| this is close to what we saw last time (Aug 27) - or slightly worse. | |
| Meanwhile phonon channels all look pretty decent. | |
| 1957 | Dial HV down to -90V nominal, -88.0 V actual |
| 2005 | HV = -88 V, Vtest = -23.1 mV, Ileak = -25.4 uA, Vdet = -77.9 V (88%). |
| also worse than last time | |
| 2005 | Dial HV down to 0V |