2020/09/19 (Saturday)
- Lab in-person: Matt
- Virtual partner: Derek
| 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 down after warmup to deal with 1K Pot partial blockage and helium in IVC. Initial LHe transfer yesterday. |
| 1000 | Matt enters lab |
| 1000 | MB = 65.5% / 165 mbar+1atm |
| 1005 | MC(Cernox)/Sorb/1K Pot = 5.36/8.4/6.59 K. G1(fridge) = 563.5 mbar (3He pump off). |
| 1005 | Turbo on IVC = 1.9 nbar. With turbo valved out for 1 minute, IVC = 19 nbar. This looks pretty good. Open Turbo valve again, we'll keep pumping on IVC. |
| 1010 | Matt Fritts body temperature = 98.0 F |
| 1010 | 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. |
| 1020 | Check pressure in 1K Pot: Mechanical gauge = 0.35 bar. 1K Pot temperature dips to 4.8 K, then up to 5.3 K, then falls again to 4.7 K. |
| 1020 | 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 10 iterations leave V4a and 1K Pot speedivalve open. 1K Pot → 3.4 K / 1.1 mbar |
| 1030 | MC(H35)/Tower = 5.36/5.35 K. (Coldplate/Still = 21.4/6.7 K. These don't have good calibrations here.) |
| 1035 | MC(H35)/Sorb = 5.35/4.2 K. G1 (fridge) = 540 mbar and falling. |
| 1035 | Open 1K Pot needle valve → 10°. 1K Pot → 2.9 K / 7.5 mbar. Fridge pressure starts falling faster. Open 1K Pot needle valve → 20°. 1K Pot → 2.7 K / 12.0 mbar, starts oscillating. G1(fridge) = 486 mbar, MC(H35) = 4.45 K, falling rapidly |
| 1040 | Open 1K Pot needle valve → 30°. 1K Pot → 2.45 K / 26.0 mbar. G1(fridge) = 402 mbar, MC(H35) = 3.26 K. |
| 1057 | Begin LHe transfer @ MB = 64.2% |
| 1100 | 1K Pot = 1.77 K / 26 mbar. MC(H35) = 2.68 K, G1 (fridge) = 190 mbar, both falling. |
| 1105 | Fill LN2 cold trap bath from 5L storage Dewar |
| 1105 | Connect hose to LN2 Dewar exhaust, open valve for slight flow - restarting Ebox purge |
| 1110 | 1K Pot = 1.63 K / 11 mbar, pressure falling. MC(H35) = 2.18 K, G1 (fridge) = 75 mbar, both falling. |
| 1115 | Open 1K Pot needle valve → 40°. 1K Pot → 1.66 K / 16.0 mbar. Then pressure starts falling again. This is a little concerning - it looks like the bad-ish 1K Pot behavior from before the warmup. |
| 1115 | End LHe transfer @ MB = 91.7% |
| 1125 | 1K Pot temp/pressure suddenly increase, good |
| 1130 | MB = 91.6% |
| 1130 | 1K Pot = 40° / 1.70 K / 36 mbar. MC(H35) = 2.03 K, G1 (fridge) = 59.3 mbar. These are starting to level out. |
| 1140 | 1K Pot = 40° / 1.69 K / 34 mbar. MC(H35) = 1.99 K, G1 (fridge) = 59.0 mbar. |
| 1150 | Plug power into DCRCs. Note: for DCRC1 (on the right), I had to slightly pull it out of the HV box connector on the left side for it to power up. |
| 1155 | Matt leaves lab |
| 1230 | 1K Pot = 40° / 1.68 K / 30 mbar. MC(H35) = 1.92 K, G1 (fridge) = 53.7 mbar. |
| 1230 | Close V3 and V9, leaving 40 mbar (G2) in the dump. Turn on 3He pump. |
| 1235 | Start circulation through Trap 1. V6 → 12.8%. Condenser peaks at 193 mbar. MC falls to 1.52 K. 1K Pot pressure rises a little for a moment. |
| Like last time, G2 peaks higher than G1. Didn't used to do that. | |
| 1240 | V6 → 13.2%. Condenser peaks at 158 mbar. MC(H35) → 1.55 K (a little higher) |
| 1245 | V6 → 13.4%. Condenser peaks at 143 mbar. MC(H35) → 1.43 K. Still → 45 mbar. |
| 1250 | V6 → 13.6%. Condenser peaks at 127 mbar. MC(H35) → 1.29 K. Still → 15 mbar. |
| 1255 | V6 → 14.0%. Condenser peaks at 133 mbar. MC(H35) → 1.16 K. Still → 5.0 mbar. |
| 1300 | MC falls to 1.13 K then bounces back up, condenser peaks again too. MC rises to 1.20 K then quickly falls to 1.12 K, rises again to 1.17 K then starts falling more slowly. This is presumably the aluminum electrode transitioning to s/c, as we see every cooldown. |
| 1305 | MC falls quickly to 0.95 K, looks like the electrode is finished transitioning. Condenser falls too. |
| 1305 | V6 → 14.4%. Condenser peaks at 128 mbar. MC(H35) → 0.81 K. Still → 3.0 mbar. |
| 1315 | V6 → 15.0%. Condenser peaks at 129 mbar. MC(H35) → 0.46 K. Still → 1.7 mbar. |
| 1325 | V6 → 100%. Condenser peaks at 124 mbar. MC(H35) → 0.21 K. Still → 0.24 mbar. |
| 1335 | Turn on MIDAS DAQ programs. Unlike last time we are cooling with the DCRCs on. If the cooldown stalls we may want to try zapping the SQUIDs. |
| 1335 | MC(H35) = 74 mK, Still = 0.170 mbar, G1/G2 = 102/103 mbar. |
| 1340 | MC(H35) = 46.0 mK, Still = 0.150 mbar, G1/G2 = 89/90 mbar. |
| 1340 | Looking at phonon channels - all have traces except DCRC1pD is railed, can't unrail it with any reasonable offset. Let's zap. |
| 1340 | Zap DCRC1,4 SQUIDs. MC warms a bit then cools. |
| 1345 | All phonon channels look OK. No pulses yet though. |
| 1350 | MC(H35) = 42.4 mK, Still = 0.130 mbar, G1/G2 = 78/78 mbar. |
| 1405 | MC(H35) = 34.3 mK, Still = 0.130 mbar, G1/G2 = 78/79 mbar. |
| 1405 | Open V14 to let the remaining mix out of the dump and into circulation. P1(Still) peaks at 140 mbar then falls again. Condenser peaks at 121 mbar. MC(H35) peaks at 87 mK. 1K Pot pressure reacts very slightly. |
| 1420 | Matt Fritts body temperature = 97.1 F |
| 1435 | MC(H35) = 34.5 mK, Still = 0.650 mbar, G1/G2 = 77/78 mbar. |
| 1435 | Close V14 |
| 1500 | MC(H35) = 31.7 mK, Still = 0.120 mbar, G1/G2 = 78/79 mbar. 1K Pot = 1.68 K / 26 mbar |
| 1730 | MC(H35) = 31.5 mK, Still = 0.120 mbar, G1/G2 = 80/80 mbar. 1K Pot = 1.68 K / 24 mbar |
| 1730 | Very occasionally seeing pulses in the pulse viewer |