2022/10/14 (Friday)
- 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 source behind lead wall on West side of lead/poly shield. |
| NaI trigger window: 7.6-11.2 MeV | |
| Cooled to base three days ago after thirteenth 5K pumpout. | |
| 1110 | MC base 31.8 mK, most spikes peaking below 36 mK, some above 50 mK |
| 1115 | MC/Coldplate = 31.7/150 mK, Still = 1.12 K / 0.110 mbar / 0 mW, G1/G2 = 125/137 mbar, 1K Pot = 45° / 1.59 K / 11±1 mbar, MB = 39.2% |
| 1115 | Close V6 to stop circulation |
| 1120 | Turn off 3He pump |
| 1120 | Close 1K Pot needle valve |
| 1200 | Close 1K Pot speedivalve, V4a, 4He pump inlet valve. Turn off 4He pump. Close recovery valve to 4He pump outlet. NOTE: remember to open recovery valve when the pump is turned back on. |
| 1200 | Open V3. This lets some pressure into the Still side (G1 falls from 19 to 13 mbar, P1 rises from 30 to 60 mbar). Close V3 again, we'll let pressure build up on the Still side. |
| 1205 | Turn on Still and MC heaters to 20 mW each |
| 1245 | Closed V1 and opened V3 a couple times to equalize the two sides of the fridge. Now leaving both open. |
| 1245 | Turn off DAQ programs and unplug DCRCs 1&3 |
| 1300 | G1(fridge) = 816 mbar. Open V9 to release mixture into dump. |
| 1450 | MC = 8.18 K. I was surprised it had gone up so much until I realized that I'd never closed the IVC valves when I started warming last time, so I've been pumping continuously on the IVC. |
| 1510 | MC = 9.02 K. Let's try reducing the heaters to keep it warm but not too warm |
| 1510 | Reduce MC and Still heat to 10 mW each Temperature flattened for a bit then started rising again, though more slowly |
| 1520 | MC = 9.23 K |
| 1520 | Reduce MC and Still heat to 5 mW each MC looks pretty flat, around 9.23 K |
| 1540 | Pry stripline elbow up with a screwdriver and wedge it with two washers on each side between the knurled knobs. Push more vacuum grease into the gap, this time trying to push it up on the inner edge with a wooden coffee stirrer. Move the washers over to get the region where they were as well. Then remove the washers and push the elbow down so the knurled knobs are touching. |
| 1545 | Fill LN2 cold trap bath |
| 1600 | MC = 9.55 K, rising - at the current rate it will hit 10K at 16:35 |
| 1600 | Reduce MC and Still heat to 3 mW each MC flattens at 9.57 K |
| 1600 | MB = 33.4%. I'm thinking of skipping today's transfer and waiting till tomorrow morning, for a more thorough pumpout maybe. At the current boiloff rate it will hit 10% at around 11:00 tomorrow |
| 2055 | MC = 10.04 K |
| 2055 | Reduce MC and Still heat to 2 mW each |