2022/10/31 (Monday)
- 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 yesterday for nineteenth 5K pumpout. Turbopumping IVC overnight. | |
| 0930 | Turbo on IVC = 1.0 nbar. With Turbo valved out for 1 minute IVC = 10 nbar. |
| 0930 | Close IVC valves on top of fridge |
| 1004 | Begin LHe transfer @ MB = 0.9% |
| 1058 | End LHe transfer @ MB = 74.9% |
| note: Mike had a problem with the storage Dewar in the liquefier room, and needs the 250L Dewar to help cool it back down. So I did a partial transfer with a partially-full 100L Dewar. We'll need to transfer again tomorrow. | |
| I'm planning to let the fridge sit at >4K for a day, start cooling tomorrow, as an experiment. We'll see whether the He buildup begins any sooner if we leave the IVC closed for a day at a temperature above the lambda point. (I'm trying to decide if what we have is actually a superleak, which would not start until we cooled the mixture to superfluid.) | |
| 1250 | Fill LN2 cold trap bath |