2022/07/31 (Sunday)
- 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 West side of lead/poly shield. |
| Fridge failure six days ago, looked like an impedance blockage. At 110 K the impedance blockage was gone. Recooling: did initial LHe transfer yesterday | |
| 1125 | MC(Cernox)/Sorb = 4.8/9.0, G1(fridge) = 551 mbar. MB = 28.9% / 126 mbar+1atm |
| 1125 | Turbo on IVC = 2.2 nbar. With Turbo valved out for 1 minute IVC = 19 nbar |
| 1139 | Begin LHe transfer @ MB = 28.9% |
| 1145 | Fill LN2 cold trap bath |
| 1150 | Close V1a, then pump out line leading to 1K Pot with scroll pump. Then switch over to 4He pump. Turn on 4He pump then change pump exhaust to recovery and open valve to recovery lines. |
| 1155 | Check pressure in 1K Pot: Mechanical gauge = 0.43 bar. (Note: V4a was closed during this check.) 1K Pot temperature dips briefly to 3.3 K |
| 1200 | Pump out 1K Pot in steps, alternating between V4a and Speedivalve. Throttle valves to keep pressure at P2 below around 10 mbar. After 6 iterations, leave both valves open. |
| 1205 | MC(Cernox)/MC(H35)/Goldman = 4.71/4.71/4.64 K. (Coldplate/Still = 2.800/3.006 kΩ = 7.36/3.33 K. These don't have good calibrations here.) |
| 1210 | Sorb = 4.0 K. G1 (fridge) = 399 mbar and falling. 1K Pot = 2.96 K / 2.0 mbar |
| 1215 | Open 1K Pot needle valve → 15°. 1K Pot → 2.5 K / 11 mbar. |
| 1220 | Open 1K Pot needle valve → 30°. 1K Pot → 2.1 K / 24 mbar. MC(Cernox) plummets to 3.3 K. |
| 1228 | End LHe transfer @ MB = 93.4% |
| 1235 | MC(Cernox) = 2.59 K and falling. 1K Pot = 1.62 K / 20 mbar |
| 1235 | Open 1K Pot needle valve → 40°. 1K Pot → 1.65 K / 32 mbar. |
| 1245 | 1K Pot = 1.57 K / 13 mbar, both falling |
| 1250 | MC (H35) = 2.08 K |
| 1250 | Open 1K Pot needle valve → 50°. 1K Pot → 1.58 K / 14 mbar. |
| 1255 | MC (H35) = 2.02 K, cooling slowly. G1(fridge) = 57 mbar, flattening |
| 1300 | 1K Pot pressure jumps - lambda point probably. Jumps off scale then waves up and down between 60 and 180 mbar |
| 2100 | MC (H35) = 1.83 K, G1(fridge) = 45 mbar. 1K Pot = 50° / 1.71 K / 80±10 mbar. |
| 2105 | Close V3 and V9, leaving 50 mbar (G2) in the dump. Turn on 3He pump. |
| 2105 | Start circulation through Trap 1. V6 → 12.6%. Condenser peaks at 170 mbar. MC(H35) → 1.2 K, then bounces back up to 1.35 K and rising. 1K Pot pressure spikes off-scale then recovers. P1 (still) → 28 mbar. |
| 2115 | V6 → 13.0%. Condenser(G1) peaks at 143 mbar. MC(H35) wiggling, went up to 1.4, now 1.25 K. Still(P1) → 9.0 mbar, although it spiked at the same time MC peaked. |
| 2130 | V6 → 13.4%. Condenser(G1) peaks at 140 mbar. MC(H35) → 1.1 K. Still(P1) → 4.5 mbar. |
| 2135 | V6 → 13.8%. Condenser(G1) peaks at 135 mbar. MC(H35) → 0.58 K. Still(P1) → 3.2 mbar. |
| 2150 | V6 → 14.5%. Condenser(G1) peaks at 135 mbar. MC(H35) → 0.40 K. Still(P1) → 1.4 mbar. |
| 2200 | V6 → 15.0%. Condenser(G1) peaks at 122 mbar. MC(H35) → 0.19 K. Still(P1) → 0.6 mbar. |
| 2220 | V6 → 100%. Condenser(G1) peaks at 110 mbar. MC(H35) → 42 mK. Still(P1) → 0.14 mbar. |