2020/10/08 (Thursday)
- Lab in-person: Matt
- Virtual partner: Michael, Ruiren / Pramod
| Setup | Run 73. DIB 1/3/4 → Stripline 43/48/41 → pi-filters 1/2/3 → Cable 3/1/2 → nothing/nothing/accessory_interposer → HV_Conn 1/3/2 → HV 1/2 → DCRCX(4)/DCRC55(1)-master; DCRC33(2) → HV control. DCRCs off. Lead/poly shield erected (4 lead walls, 2 poly walls). |
|---|---|
| Status | Cooling after warmup to deal with clogged 1K Pot. Initial LHe transfer yesterday. |
| 0915 | MB = 65.3% / 174 mbar+1atm |
| 0920 | MC(Cernox)/Sorb/1K Pot = 5.10/8.4/6.58 K. G1(fridge) = 580.1 mbar (3He pump on). |
| 0930 | Matt Fritts body temperature = 97.4 F |
| 1055 | Matt enters lab |
| 1100 | Turbo on IVC = 2.5 nbar. With turbo valved out for 1 minute, IVC = 30 nbar. Open Turbo valve again, we'll keep pumping on IVC. |
| 1100 | 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. |
| 1110 | Check pressure in 1K Pot: Mechanical gauge = 0.24 bar. 1K Pot temperature dips to 4.8 K, then up to 5.7 K |
| 1115 | Pump out 1K Pot in steps, alternating between V4a and the 1K Pot speedivalve, opening V4a for short bursts only when the mechanical gauge read above a few inches. After 8 speedivalve iterations leave V4a and 1K Pot speedivalve open. 1K Pot → 3.5 K / 0.85 mbar. Sorb falls, MC falls a little. |
| 1120 | MC(H35)/Tower = 5.14/5.14 K. (Coldplate/Still = 2.515/2.657 kΩ = 19.7/6.7 K. These don't have good calibrations here.) |
| 1125 | MC(H35)/Sorb = 5.14/4.3 K. G1 (fridge) = 550 mbar and falling. |
| 1125 | Open 1K Pot needle valve → 10°. 1K Pot → 2.7 K / 12 mbar. Open 1K Pot needle valve → 20°. 1K Pot → 2.3 K / 30 mbar, oscillating. MC(H35) → 3.4 K. G1(fridge) → 460 mbar. |
| 1135 | 1K Pot = 2.2 K / 30 mbar. MC(H35) = 3.16 K, G1 (fridge) = 366 mbar, both falling. |
| 1145 | 1K Pot = 1.7 K / 30 mbar. MC(H35) = 2.82 K, G1 (fridge) = 237 mbar, both falling. |
| 1150 | Fill LN2 cold trap bath |
| 1150 | 1K Pot = 1.68 K / 30 mbar, not oscillating. MC(H35) = 2.61 K, G1 (fridge) = 168 mbar, both falling. |
| 1150 | Open LN2 Dewar vent valve enough for slight flow, connect to Ebox purge |
| 1200 | 1K Pot = 1.61 K / 17 mbar, pressure falling. MC(H35) = 2.21 K, G1 (fridge) = 78 mbar, both falling. |
| 1200 | Open 1K Pot needle valve → 30°. 1K Pot → 1.61 K / 17 mbar, not much change |
| MC is getting close to the lambda point, 2.17 K. I think 1K Pot pressure usually jumps at that point - we'll wait a bit | |
| 1205 | MC(H35)/Tower = 2.12/2.13 K. Coldplate/Still = 3.106/3.176 kΩ =? 4.08/2.63 K. |
| 1210 | 1K Pot = 1.58 K / 10 mbar. MC(H35) = 2.10 K, G1 (fridge) = 61 mbar, both flattening. |
| 1210 | Open 1K Pot needle valve → 40°. 1K Pot → 1.60 K / 14 mbar |
| MC(H35) = 2.07 K … now 1K Pot pressure/temperature shoot up, → 1.8 K / off scale, then start swinging… | |
| 1215 | 1K Pot = 1.75 K / 400 mbar, oscillating. MC(H35) = 2.04 K, G1 (fridge) = 59.7 mbar. |
| 1250 | MC(H35)/Tower = 1.94/1.95 K. Coldplate/Still = 3.190/3.178 kΩ =? 3.61/2.62 K. |
| 1300 | 1K Pot = 40° / 1.75 K / 350±50 mbar. |
| Pot is running a bit high, let's step back on the needle valve | |
| 1300 | Adjust 1K Pot needle valve → 35°. 1K Pot → 1.71 K / 65±5 mbar |
| 1310 | Matt leaves lab |
| 1355 | 1K Pot = 35° / 1.71 K / 65±5 mbar. MC(H35) = 1.87 K, G1 (fridge) = 49.0 mbar. |
| 1355 | Close V3 and V9, leaving 39 mbar (G2) in the dump. Turn on 3He pump. |
| 1400 | Matt Fritts body temperature = 97.4 F |
| 1400 | Start circulation through Trap 1. V6 → 12.8%. Condenser peaks at 164 mbar. (G2 peaks higher than G1.) MC falls to 1.63 K. 1K Pot spikes then settles. |
| 1405 | V6 → 13.2%. Condenser peaks at 164 mbar. MC(H35) → 1.54 K |
| 1410 | V6 → 13.4%. Condenser peaks at 188 mbar. MC(H35) → 1.55 K (went up a little) |
| 1420 | V6 → 13.6%. Condenser peaks at 225 mbar. MC(H35) → 1.50 K. Still → 75 mbar. |
| 1425 | V6 → 14.0%. Condenser peaks at 204 mbar. MC(H35) → 1.15 K. Still → 4.5 mbar. |
| 1440 | Al superconducting transition: MC falls to 1.13 K, rises to 1.26, falls to 1.09, rises to 1.24, falls to 1.13, rises to 1.24, falls to 1.16, rises to 1.26, then starts to fall steadily |
| 1450 | MC starts rising again - this looks unusual. Rises to 1.4 K - Still and Condenser pressures rising strongly… |
| 1455 | MC/Condenser/Still peaked at 1.45 K / 260 mbar / 150 mbar, all falling now |
| 1500 | V6 → 14.4%. Condenser → 183 mbar. MC(H35) → 0.93 K. Still → 4.0 mbar. |
| 1605 | V6 → 15.0%. Condenser peaks at 216 mbar. MC(H35) → 0.61 K. Still → 2.4 mbar. |
| 1615 | V6 → 100%. Condenser peaks at 232 mbar. MC(H35) → 0.31 K. Still → 0.28 mbar. |
| 1630 | MC(H35) = 58 mK, Still = 0.170 mbar, G1/G2 = 177/169 mbar. |
| 1650 | MC(H35) = 33.4 mK, Still = 0.140 mbar, G1/G2 = 138/132 mbar. |
| 1650 | Open V14 to let the remaining mix out of the dump and into circulation. P1(Still) peaks at 65 mbar then falls again. MC(H35) peaks at 80 mK. Condenser peaks at 206 mbar. |
| 1715 | MC(H35) = 35.5 mK, Still = 0.800 mbar, G1/G2 = 140/133 mbar. |
| 1715 | Close V14 |
| 1715 | MB = 52.4% |
| 1745 | MC(H35) = 31.4 mK, Still = 0.130 mbar, G1/G2 = 144/138 mbar. 1K Pot = 1.70 K / 60 mbar |
| MC looks kind of flat. This is pretty similar to Sep 19 - we had mediocre base at that time, Tower ~ 65 mK. Not as good as Aug 20. |