2018/05/07 (Monday)
| Status: Initial LHe transfer last Friday, pumping IVC over weekend. Mixture open from dump to fridge through (cold) LN2 Trap 1. | |
| 0945 | MC(cernox) = 6.0 K, 1K pot = 7.0 K, Sorb = 9.4 K, G1 = 551.6 mbar, MB = 52.8% |
| 0955 | Turbo on IVC = 1.4 nbar. IVC = 14 nbar with turbo valved out. |
| 1000 | Check pressure in warm LN2 Trap 2: 18.2 mbar. Pump out with scroll. |
| 1005 | Pump out line to 1K Pot with scroll pump. Valve out pump and open 1K Pot speedivalve to check pot pressure: 6/30 bar (on mechanical gauge). |
| 1010 | Pump out 1K Pot with scroll pump. Pot temperature doesn't change much, it's hovering around its 7K max |
| 1015 | Switch to pumping 1K Pot with 4He pump. Open valve on pump exhaust line and valve on recovery line to connect pump exhaust to recovery. |
| 1020 | 4He pump pressure running high, even with valves closed so that it's only pumping on P2. Pumps down to 8 mbar. |
| Oil in 4He pump looked low. Put some Leybonol LVO 100 Mineral Oil in the center spout on top, until the level is up about 20% when the pump is off. Now it seems to pump down. | |
| 1055 | 1K Pot > 7.0 K / 0.28 mbar Open 1K Pot Needle Valve to ~10 degrees. No change. |
| 1100 | Opening the needle valve much farther than usual produces no change in pressure or temperature |
| 1105 | Messing around with needle valve, pump valve, finally got the pressure to increase and the temperature to fall. Find a spot for the needle valve where the pressure starts to come up (much more open than usual) |
| 1110 | 1K Pot = 3.9 K / 1000 mbar (off scale; about 1/30 bar on mechanical gauge) |
| Fridge pressure has fallen since we started messing with the pot, so something is happening. | |
| 1120 | 1K Pot = 3.7 K / 60 mbar. Have been adjusting the needle valve open and closed to get the pressure above 20 but below 1000. |
| 1125 | Tower/MC(Cernox)/Coldplate/Still = 6.0/5.96/14.5/5.3 K, Fridge (G1) = 542 mbar |
| 1125 | 1K Pot = 3.7 K / 60 mbar, steady. MC(Cernox) temperature and Fridge pressure slowly falling. |
| 1135 | MC(Cernox) = 5.93 K, Fridge(G1) = 541 mbar, 1K Pot = 3.72 K / 55 mbar. |
| 1145 | Fill LN2 cold trap bath |
| 1150 | MC(Cernox) = 5.86 K, Fridge(G1) = 537 mbar, 1K Pot = 3.71 K / 55 mbar. |
| 1152 | Fill LN2 cold trap full. |
| 1215 | MC(Cernox) = 5.71 K, Fridge(G1) = 533 mbar, 1K Pot = 3.70 K / 55 mbar. |
| 1235 | MC(Cernox) = 5.59 K, Fridge(G1) = 533 mbar, 1K Pot = 3.70 K / 55 mbar. |
| 1310 | Tower/MC(Cernox)/Coldplate/Still = 5.4/5.43/12.0/5.3 K, Fridge (G1) = 533 mbar |
| 1405 | MC(Cernox) = 5.15 K, Fridge(G1) = 532 mbar, 1K Pot = 3.67 K / 55 mbar. |
| 1439 | Start LHe transfer @ MB = 44.9% |
| starting transfer caused a surge in 1K Pot pressure and drop in temperature. MC cools a little more quickly, fridge pressure falls. | |
| 1450 | MC(Cernox) = 4.93 K, Fridge(G1) = 481 mbar, 1K Pot = 3.36 K / 350±50 mbar. |
| 1500 | MC(Cernox) = 4.87 K, Fridge(G1) = 457 mbar, 1K Pot = 3.34 K / 150 mbar. |
| 1510 | End LHe transfer @ MB = 91.3% |
| 1520 | MC(Cernox) = 4.82 K, Fridge(G1) = 486 mbar, 1K Pot = 3.23 K / 45 mbar. Open needle valve a few more degrees |
| 1550 | MC(Cernox) = 4.70 K, Fridge(G1) = 502 mbar, 1K Pot = 3.28 K / 50 mbar. |
| 1620 | MC(Cernox) = 4.57 K, Fridge(G1) = 510 mbar, 1K Pot = 3.37 K / 40 mbar. Open needle valve a few more degrees |
| 1635 | MC(Cernox) = 4.50 K, Fridge(G1) = 512 mbar, 1K Pot = 3.47 K / 110±10 mbar. |
| 1635 | Fill LN2 cold trap bath |