2022/07/27 (Wednesday)
- Lab in-personnel: Matt, Giulia
| 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 two days ago, looks like an impedance blockage. V9 open to dump. DCRC 1&3 off. | |
| LN2 Trap 1, which we were using during the run, is warm now, needs to be pumped out. | |
| 0505 | Condenser (G1) = 320 mbar, Still = 0.021 mbar, MC = 1.03 K. Close V6. |
| 0930 | Turn off 3He pump. |
| 0940 | MC/Coldplate = 1.68/2.12 K, Still = 1.76 K / pressure offscale / 0 mW, G1/G2 = 296/272 mbar, 1K Pot = 70° / 1.55 K / 8.5±0.5 mbar, MB = 46.7% |
| 0950 | Fill LN2 cold trap bath |
| 1140 | Close 1K Pot needle valve. 1K Pot → 1.41 K / 2.6 mbar. |
| 1145 | Close 1K Pot speedivalve. Switch 4He pump outlet valve from Recovery to Exhaust. Close red 4He Pump Recovery valve. |
| 1145 | Close V4a and the 4He Pump inlet valve. Then turn off 4He pump. |
| 1215 | Condenser (G1) =283 mbar. Open V3 to let mix from condenser side to still side. Condenser falls to 120 mbar, then rises as G2 falls (mixture from the dump going through Trap 2). Settles at 196 mbar. |
| 1225 | LHe Recovery rising 16 cuft/hr |
| 1230 | Let 1.6 mbar He gas into vacuum manifold. Then open cryostat vacuum jacket valve to let this into the vacuum jacket. Vacuum Jacket → 0.054 mbar. |
| 1237 | MB = 42.4% |
| 1242 | Recovery = 620500 cuft / 162 cuft/hr |
| 1250 | Recovery = 148 cuft/hr, MB = 38.1% |
| 1300 | Recovery = 120 cuft/hr, MB = 36.1% |
| 1315 | MB = 34.1% |
| 1330 | Recovery = 84 cuft/hr, MB = 31.9% |
| 1337 | Recovery = 620600 cuft |
| 1345 | MB = 30.4% |
| 1400 | Recovery = 61 cuft/hr, MB = 29.0% |
| 1400 | Fridge+dump (G2) = 177 mbar. 1K Pot = 4.31 K, flat. MC = 2.23 K, flat. |
| 1405 | Let 6.3 mbar He gas into pumping station manifold, then let this into the IVC. IVC → 0.012 mbar. |
| MC(Cernox) temperature shoots up to 3.0 K. Condenser (G1) → 250 mbar and rising. | |
| 1425 | MC (Cernox) = 3.5 K, then suddenly climbs to 4.3 K |
| 1505 | Recovery = 40 cuft/hr, MB = 24.2% |
| 1510 | Turn on Still Heater and MC Heater to 20 mW each. |
| 1515 | MC/Still = 4.7/5.2 K, 1K Pot = 4.3 K |
| 1515 | Start pumping mixture to dump. Turn on 3He pump. Close V13b to block return to LN2 Trap 2. Open V6 to 13%. After P1 falls into range open V6 to 30%. |
| 1520 | Close Still gate valve and V1, to pump just on LN2 Trap 2 until it's empty. |
| 1535 | Isolate LN2 Trap 2 which is now pumped out to dump (close V12b+speedivalve) |
| 1535 | Continue pumping on the fridge lines (open V1 and Still Gate Valve) |
| 1544 | Recovery = 620700 cuft |
| 1610 | Stop pumping out fridge (close V1, V3, Still Gate valve, Condenser speedivalve). G2(Dump) = 735.3 mbar |
Barometric pressure = 29.82“ (source is https://w1.weather.gov/data/obhistory/KMSP.html.) G2 = 729.9 mbar. Corrected dump pressure = 731.9 mbar. Slightly higher than Run 75. Ptrue[mbar] = Pdisplay[mbar] + ( Pbar[inHg] - 29.92 ) * 33.86 |
|
| 1625 | Recovery = 32 cuft/hr, MB = 20.0% |
| 1628 | Let 2.2 mbar He gas into vacuum manifold. Then open cryostat vacuum jacket valve to let this into the vacuum jacket. Vacuum Jacket → 0.063 mbar. |
| 1630 | Remove PuBe source can from its paraffin drum, disconnect it from the plexiglass rod, and put it in plastic cup and lower it on string into lead/poly shield on NW corner. This is the same configuration as for the strong Ge activation - source should be at about SiHV detector level. We're going to take overnight NaI scan data. |
| 1635 | Recovery = 125 cuft/hr |
| 1645 | Recovery = 144 cuft/hr, MB = 17.5% |
| 1655 | MC/Still/1K Pot = 4.8/5.4/4.3 K |
| 1655 | Let 14 mbar He gas into pumping station manifold, then let this into the IVC. IVC → 0.030 mbar. |
| 1700 | Recovery = 144 cuft/hr, MB = 14.8% |
| 1703 | Recovery = 620800 cuft |
| 1715 | Skipping the NaI tests. Put PuBe source back into paraffin drum, put drum behind lead wall on W side |
| 1715 | Recovery = 136 cuft/hr, MB = 12.1%. (17:15:25 620828.05) |
| 17:20:55 620840.2 | |
| 1955 | MC/1K Pot = 5.7/7.0 K |
| 2210 | MC/Still = 20/30 K |