2022/10/19 (Wednesday)
- Lab in-personnel: Zach, Himangshu
| 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 source behind lead wall on West side of lead/poly shield. |
| NaI trigger window: 7.6-11.0 MeV | |
| Warmed up and pumped out IVC overnight for fifteenth 5K pumpout. | |
| 1100 | Turbo on IVC = 0.86 nbar. With Turbo valved out for 1 minute IVC = 10 nbar. |
| 1101 | Close IVC valves on top of fridge |
| 1105 | 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. |
| 1110 | 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). |
| 1118 | Start pumping 1K Pot continuously |
| 1130 | MC = 5.45 K, cooling slowly. 1K Pot = 3.31 K / 2.6 mbar, cooling slowly |
| 1130 | Open 1K Pot needle valve → 15°. 1K Pot → 3.06 K / 6.5 mbar |
| 1135 | Open 1K Pot needle valve → 30°. 1K Pot → 2.96 K / 7.5 mbar |
| 1143 | Open 1K Pot needle valve → 45°. 1K Pot → 2.60 K / 11 mbar |
| 1147 | G1/G2 = 371/340 mbar dropping linearly |
| 1147 | MC/1Kpot = 3.24/2.53K dropping linearly |
| 1325 | MC = 1.91 K. It flattened around 2.5 K for about a half hour then dropped quickly to 1.95 K (helium lambda point) |
| 1359 | Close V3 and V9, leaving 33.4 mbar mixture in dump |
| 1400 | Turn on 3He pump |
| 1406 | Start circulation through Trap 1. V6 → 12.6%. Condenser peaks at 251 mbar. MC(H35) → 1.41 K. Still → 1.45 K / 36 mbar. |
| 1414 | Set NaI trigger window to 7-11 MeV |
| 1414 | V6 → 13.0%. Condenser(G1) peaks at 275 mbar. MC(H35) → 1.28 K. Still(P1) → 1.57 K / 8 mbar. |
| 1439 | V6 → 13.4%. Condenser(G1) peaks at 273 mbar. MC(H35) → 1.14 K. Still(P1) → 1.17 K / 4.0 mbar. |
| 1450 | V6 → 13.8%. Condenser(G1) didn't really peak, a small kink in the falling curve. MC(H35) → 0.89 K. Still(P1) → 1.13 K / 1.08 mbar. |
| 1454 | V6 → 14.4%. Condenser(G1) peaks at 187.8 mbar. MC(H35) → 0.52 K. Still(P1) → 1.12 K / 1.0 mbar. |
| 1504 | V6 → 15.0%. Condenser(G1) peaks at 183.6 mbar. MC(H35) → 0.27 K. Still(P1) → 1.12 K / 0.6 mbar. |
| 1510 | V6 → 100%. Condenser(G1) peaks at 179.4 mbar. MC(H35) → 0.137 K. Still(P1) → 1.06 K / 0.17 mbar. |
| 1521 | Plug in DCRCs 1 and 3 |
| 1522 | MC = 50mK, G1 = 154mbar |
| 1554 | Open V14 to pull the rest of the mixture out of the dump into circulation. |
| MC rises to 66 mK, Still peaks above 30 mbar then falls again, Condenser rises to 148 mbar. 1K Pot unaffected. | |
| as usual we'll wait till Still is below 1 mbar then close V14. | |
| 1541 | Begin LHe transfer @ MB = 33.5% |
| 1610 | Fill LN2 cold trap dewar |
| 1617 | Still = 0.8 mbar. close V14 |
| 1624 | End LHe transfer @ MB = 92.0% |
| 1710 | Start DAQ programs and check phonon channels, all working. Most baselines are still near -0.8 V, except DCRC3pD. |
| 1720 | Adjust phonon offsets to get all channels near -0.80 V |
| 1725 | Dial HV up to -109.25V nominal, -107.1V actual, for 15% prebias (using RootSequencer) |
| 1731 | Dial HV down to -95V nominal, -92.8V actual |
| 1735 | HV = -92.8 V, Vtest = -22.3 mV, Ileak = -24.5 uA, Vdet = -83 V (89%). Leakage is a little high |
| 1735 | Dial HV down to -94V nominal, -91.9V actual |
| 1735 | HV = -91.8 V, Vtest = -20.9 mV, Ileak = -23 uA, Vdet = -82.6 V (90%). |
| 1735 | MC = 29.4 mK |
| 1741 | Start -82.6 V PuBe data series 46 min long, SiHV-triggered with 1000 initial randoms, 5 Hz in-run randoms, trigger on DCRC1pB threshold 10. Start series with the Start Button |
| NOTE: the NaI trigger window has been changed. We had been using an upper threshold of 11.0 MeV thinking that was low enough to be below saturation and therefore cut out muons. But we took a NaI spectrum scan recently and found that some detectors have thresholds below 11.2 MeV. So we've reduced the upper edge to 11.0 MeV. Should reduce trigger rate from around 11 Hz to around 8 Hz. | |
| 1742 | HV = -91.7 V, Vtest = -20.8 mV, Ileak = -22.9 uA, Vdet = -82.6 V (90%). |
| 1832 | Start -82.6 V PuBe data series 202 min long, NaI-triggered with 1000 initial randoms, 5 Hz in-run randoms, trigger on DCRC4pA threshold 20. Start series with the Start Button |
| 2157 | Start -82.4 V PuBe data series 42 min long, SiHV-triggered with 1000 initial randoms, 5 Hz in-run randoms, trigger on DCRC1pB threshold 10. Start series with the Start Button |
| 2200 | HV = -91.7 V, Vtest = -21 mV, Ileak = -23.1 uA, Vdet = -82.4 V (90%). |
| 2240 | Start -82.5 V PuBe data series 533 good min long, NaI-triggered with 1000 initial randoms, 5 Hz in-run randoms, trigger on DCRC4pA threshold 20. Start series with the Start Button |
| DAQ crash at 7:42 AM, dumps after 533 are empty | |
| 2240 | HV = -91.7 V, Vtest = -20.8 mV, Ileak = -22.9 uA, Vdet = -82.5 V (90%). |