2018/04/04 (Wednesday)
| Status: Warming fridge. All mixture in dump. 1K Pot needle valve open. Helium gas in cryostat vacuum jacket. Still and MC heaters on @ 20 mW. | |
| 0935 | MC(Cernox)/1KPot/Sorb = 78/>7/147 K, Main bath outer surface = 21.7 C. |
| 0940 | Let 100 mbar N2 gas into vacuum manifold. Then open cryostat vacuum jacket valve to let this into the vacuum jacket. Vacuum jacket → 4.6 mbar |
| 0945 | Turn off Still and MC heaters. |
| 0950 | MC(Cernox)/Sorb = 78.76/148.6 K, Main bath outer surface = 21.3 C. |
| 1000 | MC(Cernox)/Sorb = 79.36/150.5 K, Main bath outer surface = 20.8 C. |
| 1030 | MC(Cernox)/Sorb = 81.81/161.7 K, Main bath outer surface = 19.7 C. |
| 1130 | MC(Cernox)/Sorb = 89.00/189.6 K, Main bath outer surface = 19.1 C. |
| 1210 | MC(Cernox)/Sorb = 95.27/208.8 K, Main bath outer surface = 19.2 C. |
| 1300 | MC(Cernox)/Sorb = 103.86/230.8 K, Main bath outer surface = 19.3 C. |
| The warming time constant seems to have settled to about 19 hours. This should hit dew point (273 K) early Friday morning. | |
| Wouldn't hurt to add more N2… | |
| 1305 | Let 100 mbar N2 gas into vacuum manifold. Then open cryostat vacuum jacket valve to let this into the vacuum jacket. Vacuum jacket → 8.6 mbar |
| 1330 | MC(Cernox)/Sorb = 109.18/242.6 K, Main bath outer surface = 19.3 C. |
| 1420 | MC(Cernox)/Sorb = 118.06/>249.9 K, Main bath outer surface = 19.4 C. |
| The warming time constant is now around 17 hours. Predicted to hit dew point (273 K) 1:20 am Friday morning. | |
| 1505 | IVC = 0.74 mbar. This is the helium I put in yesterday, and whatever else was in there. |
| 1515 | Let about 0.4 N2 gas into IVC. This causes some extra warming. |
| 1520 | MC(Cernox) = 130.89 K, Main bath outer surface = 19.7 C. |
| 1525 | Check pressure in LHe Cold Trap at G1: 37 mbar. Pump out with scroll pump. |
| 1530 | MC(Cernox) = 134.30 K, Main bath outer surface = 19.7 C. |
| 1535 | Check Condenser/Still pressure at G1/P2: 0.6/0.42 mbar. Pump out with scroll pump. |
| 1540 | Check pressure in warm LN2 Trap 1 : 64.5 mbar. Pump out with scroll pump. |
| 1540 | MC(Cernox) = 136.89 K, Main bath outer surface = 19.8 C. |
| 1600 | Check pressure in warm LN2 Trap 2 : 8.0 mbar. (This wasn't used during the run.) Pump out with scroll pump. |
| 1600 | MC(Cernox) = 141.11 K, Main bath outer surface = 19.8 C. |
| 1635 | MC(Cernox) = 147.53 K, Main bath outer surface = 19.9 C. |
| Seem to be past the temporary warming effect from adding N2 to the IVC. The warming time constant is now around 14 hours. Predicted to hit dew point (273 K) 18:16 pm Thursday night. Hopefully earlier, then we can pump out the vacuum jacket overnight. |
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| 1835 | MC(Cernox) = 166.34 K |