2022/11/01 (Tuesday)
- Lab in-personnel: Matt
| 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 W side of fridge. NaI array trigger thresholds: 7.0 - 11.0 MeV |
| Warmed up two days ago for nineteenth 5K pumpout. Left IVC valves closed overnight. | |
| 1005 | Check pressure in IVC: 10 nbar. Close IVC valves again. |
| 1005 | MC/1KPot/Sorb = 5.24/6.91/8.8 K |
| 1005 | 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. |
| 1010 | Pump out 1K Pot slowly, throttling the flow at the valve at the pump inlet, opening just until the pump gets louder, then waiting, then opening a little more, etc. With pump just a little loud, can see pressure go down at the mechanical gauge. When this is low, open valve a bit more. When P2 gets below 20 mbar open valve all the way. |
| 1015 | 4He pump valve open all the way. |
| 1015 | 1K Pot = 3.39 K / 2.4 mbar. G1 (fridge+dump) has fallen from 544→529 mbar. MC has fallen from 5.24→5.22 K. |
| 1015 | Open 1K Pot needle valve → 15°. 1K Pot → 3.11 K / 5.5 mbar |
| 1020 | Open 1K Pot needle valve → 30°. 1K Pot → 2.92 K / 7.0 mbar |
| MC drops quickly from 4.8 → 3.4 K | |
| 1030 | Open 1K Pot needle valve → 45°. 1K Pot → 2.58 K / 9.5 mbar |
| 1040 | Fill LN2 cold trap bath |
| 1055 | MC/Still/1KPot = 2.98/2.78/2.29. G1(fridge+dump) = 270 mbar and falling. |
| 1215 | MC/Still/1KPot = 1.89/1.92/1.54. G1(fridge+dump) = 49 mbar and pretty flat. |
| 1215 | Close V3 and V9, leaving 47 mbar mixture in dump (G2) |
| 1215 | Turn on 3He pump. G1(condenser) → 60 mbar |
| 1220 | Start circulation through Trap 1. V6 → 12.6%. Condenser peaks at 301 mbar. MC(H35) → 1.35 K. Still → 1.39 K / 11 mbar |
| 1225 | V6 → 13.0%. Condenser(G1) peaks at 234 mbar. MC(H35) → 1.13 K. Still(P1) → 1.19 K / 4.5 mbar. |
| 1227 | Begin LHe transfer @ MB = 47.6% |
| 1230 | 1K Pot = 1.67 K / 24 mbar |
| 1230 | V6 → 13.4%. Condenser(G1) peaks at 188 mbar. MC(H35) → 1.13 K. Still(P1) → 1.14 K / 3.0 mbar. |
| MC wiggled between 1.11 and 1.15 K, going through Al transition | |
| 1235 | V6 → 13.8%. Condenser(G1) peaks at 157 mbar. MC(H35) → 0.85 K. Still(P1) → 1.07 K / 1.6 mbar. |
| 1240 | V6 → 14.4%. Condenser(G1) peaks at 147 mbar. MC(H35) → 0.57 K. Still(P1) → 1.07 K / 0.8 mbar. |
| 1245 | V6 → 15.0%. Condenser(G1) peaks at 146 mbar. MC(H35) → 0.42 K. Still(P1) → 1.07 K / 0.55 mbar. |
| 1250 | V6 → 100.%. Condenser(G1) peaks at 144 mbar. MC(H35) → 0.17 K. Still(P1) → 1.05 K / 0.14 mbar. |
| 1255 | 1K Pot = 1.53 K / 8.5±0.5 mbar. |
| 1305 | MC = 68 mK. Still = 1.05 K / 0.12 mbar. G1/G2 = 124/126 mbar. 1K Pot = 1.52 K / 7.5±0.5 mbar. |
| 1305 | Open V14 to pull the rest of the mixture out of the dump into circulation. Still peaks at 80 mbar, Condenser peaks at 182 mbar, MC peaks at 111 mK, then all relax again. 1K Pot mostly unaffected. |
| 1309 | End LHe transfer @ MB = 92.9% |
| 1330 | Still = 0.80 mbar. Close V14 |
| 1355 | MC = 28.7 mK |
| 1505 | MC = 27.3 mK. Cold! |
| 1510 | Plug in DCRCs 1&3 |
| 1520 | Check phonon channels. Relock most of them, then baselines return to around -0.8 V. Adjust offsets to target -0.80 V baselines. But it seems to be a moving target because the MC is warming now that the DCRCs are running. |
| 1525 | MC = 28.5 mK and still rising a bit. |
| 1550 | MC = 28.9 mK and flattening. Fine tune offsets to get all phonon baselines near -0.80 V |