2022/10/28 (Friday)
- 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 W side of fridge. NaI array trigger thresholds: 7.0 - 11.0 MeV |
| Warmed up yesterday for eighteenth 5K pumpout. Pumping IVC overnight. | |
| 0934 | Begin LHe transfer @ MB = 0.2% |
| 0935 | Turbo on IVC = 1.0 nbar. With Turbo valved out for 1 minute IVC = 10 nbar. |
| 0940 | Close IVC valves on top of fridge |
| 0945 | Fill LN2 cold trap bath |
| 0945 | MB = 22.7% |
| 0945 | 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 = 0.32 bar on mechanical gauge. |
| 0950 | Pump out 1K Pot slowly, following new procedure of throttling the flow at the valve at the pump itself, opening just until the pump got 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. |
| 0955 | 4He pump valve open all the way. |
| 0955 | 1K Pot = 3.20 K / 2.4 mbar. G1 (fridge+dump) has fallen from 550→415 mbar. MC has fallen from 5.95→5.87 K. Actually all of these started getting cooler when I started the transfer. |
| 1000 | MC = 5.84 K, cooling slowly. 1K Pot = 3.16 K / 2.4 mbar |
| 1000 | Open 1K Pot needle valve → 15°. 1K Pot → 2.97 K / 5.5 mbar |
| 1005 | Open 1K Pot needle valve → 30°. 1K Pot → 2.86 K / 6.5 mbar |
| MC falls quickly to 3.26 K | |
| 1010 | Open 1K Pot needle valve → 45°. 1K Pot → 2.73 K / 9.5 mbar |
| 1015 | G1 (fridge+dump) = 326 mbar and falling. MC/Still = 3.16/3.11 K |
| 1027 | End LHe transfer @ MB = 94.1% |
| 1015 | G1 (fridge+dump) = 253 mbar and falling. MC/Still = 2.96/2.73 K |
| 1045 | G1 (fridge+dump) = 213 mbar and falling. MC/Still = 2.84/2.60 K. 1K Pot = 1.99 K / 11 mbar |
| 1215 | G1(fridge) = 34.5 mbar. MC = 1.72 K. 1K Pot = 1.51 K / 6.5 mbar |
| 1215 | Close V3 and V9, leaving 22 mbar mixture in dump (G2) |
| 1215 | Turn on 3He pump. G1(condenser) → 43 mbar |
| 1215 | Start circulation through Trap 1. V6 → 12.6%. Condenser peaks at 218 mbar. MC(H35) → 1.40 K. Still → 1.44 K / 30 mbar |
| 1225 | V6 → 13.0%. Condenser(G1) peaks at 245 mbar. MC(H35) → 1.30 K. Still(P1) → 1.32 K / 9.5 mbar. |
| 1230 | V6 → 13.4%. Condenser(G1) peaks at 236 mbar. MC(H35) → 1.10 K. Still(P1) → 1.09 K / 2.8 mbar. |
| 1235 | V6 → 13.8%. Condenser(G1) peaks at 200 mbar. MC(H35) → 0.92 K. Still(P1) → 1.04 K / 1.5 mbar. |
| 1240 | V6 → 14.4%. Condenser(G1) peaks at 179 mbar. MC(H35) → 0.76 K. Still(P1) → 1.02 K / 0.8 mbar. |
| 1245 | V6 → 15.0%. Condenser(G1) peaks at 178 mbar. MC(H35) → 0.63 K. Still(P1) → 1.03 K / 0.55 mbar. |
| 1251 | V6 → 100.%. Condenser(G1) peaks at 177 mbar. MC(H35) → 0.34 K. Still(P1) → 0.99 K / 0.17 mbar. |
| 1322 | MC = 38 mK. Still = 1.06 K / 0.090 mbar. G1/G2 = 125/110 mbar. 1K Pot = 1.56 K / 10.0±0.5 mbar. |
| 1323 | Open V14 to pull the rest of the mixture out of the dump into circulation. Still peaks at 30 mbar, Condenser peaks at 176 mbar, MC peaks at 64 mK, then all relax again. 1K Pot unaffected. |
| 1329 | Plug in DCRCs 1 and 3 |
| 1348 | Still = 0.70 mbar. Close V14 |