2022/12/04 (Sunday)
- Lab in-personnel: Zach
| 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 undergoing scan, trigger threshold varies. |
| Cooled to base two days ago after twenty-ninth 5K pumpout. | |
| 0805 | DCRC1pA baseline = -0.790 V |
| 0805 | DCRC1pA baseline = -0.788 V. I've had the pulse viewer scale locked in a convenient place so I can more easily see whether the baseline rises. It seemed to be elevated to around -0.786, then relaxed again. This coincided with a large MC temperature spike, 74 mK peak from baseline 32 mK. So looks like the larger temperature spikes have some effect on the phonons, though not a huge one. |
| 0820 | MC base = 31.2 mK |
| 0945 | DCRC1pA baseline = -0.785 V. A little elevated, but this time it does not coincide with a big temperature spike. |
| 1025 | DCRC1pA baseline = -0.783 V. Also there's a large temperature spike now, peaked at 87 mK. |
| 1030 | DCRC1pA baseline = -0.783 V, still. |
| 1035 | DCRC1pA trace wiggly, baseline above -0.770… That state only lasted about a minute. Then the baseline settled at -0.780 V |
| 1040 | More wiggles, baseline around -0.775 V. Wiggles mostly go away after a minute. |
| 1045 | DCRC1pA baseline = -0.777 V |
| 1055 | DCRC1pA baseline = -0.774 V |
| 1105 | DCRC1pA baseline = -0.765 V |
| 1110 | DCRC1pA baseline = -0.747 V |
| 1115 | DCRC1pA baseline = -0.740 V |
| So it was about 43 hours after starting circulation (fully opening V6) that we lost the phonon channels. Pretty typical. | |
| 1159 | Fill LN2 cold trap bath |
| 1200 | Close V6 to stop circulation. |
| 1204 | V6 is now fully closed (light is off on IGH, Still pressure is rising, Condenser pressure falling). Turn off 3He pump |
| 1205 | Close 1K Pot needle valve |
| 1206 | Stop DAQ programs and unplug DCRCs 1&3 |
| 1210 | Open V3, releasing pressure from Condenser side to Still side |
| 1211 | Turn on Still and MC heaters to 20 mW each |
| 1214 | 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. |
| 1310 | MC/1KPot = 3.92/4.12 K. G1(fridge) = 795 mbar. |
| 1310 | Open V9 to release pressure into the dump. |
| 1407 | MC/1KPot = 5.91/4.36 K and flat-ish |
| 1408 | Check pressure in IVC: 86 nbar |
| 1409 | Start pumping out IVC with turbo pump. |
| 1552 | Tower = 10.01 K. Turn off MC and Still heaters |