2021/04/19 (Monday)
- Lab in-person: Matt
- Virtual partner: Derek
| Status | Run 74 in progress. Cooldown failed during initial LHe transfer, large leak in IVC, can't pump it below 0.16 mbar. |
|---|---|
| 0830 | Looks like Main Bath is boiled off MC(Cernox)/Sorb/1K Pot = 6.30/12.8/>7 K |
| 0830 | IVC = 2.2 mbar |
| 1050 | Matt enters lab |
| 1050 | IVC = 0.46 mbar. (Interesting - why is it lower?) Start pumping out IVC with Scroll Pump. After 10 minutes, Scroll is still at 0.22 mbar. So leak is still strong. |
| 1050 | MC(Cernox)/Sorb = 7.6/15.6 K |
| 1130 | Isolate IVC and move pump manifold hose to the Cryostat Vacuum Jacket port. Pump out line to CVJ. |
| 1145 | Recovery = 20.4 cuft/hr |
| 1145 | Let 4.6 mbar He gas into vacuum manifold. Then open cryostat vacuum jacket valve to let this into the vacuum jacket. Vacuum Jacket → 0.14 mbar. |
| 1155 | Let 4.6 mbar He gas into vacuum manifold. Then open cryostat vacuum jacket valve to let this into the vacuum jacket. Vacuum Jacket → 0.25 mbar. |
| 1215 | Reconnect pump hose to IVC port and pump out line. |
| 1215 | MC(Cernox)/Sorb = 9.2/17.8 K |
| 1215 | Recovery = 16.2 cuft/hr |
| 1220 | IVC = 0.46 mbar. Start pumping IVC with Scroll Pump. After 10 minutes, still stuck at 0.25 mbar. Stop pumping IVC. |
| 1405 | MC(Cernox)/Sorb = 12.0/22 K |
| 1405 | Recovery = 12.0 cuft/hr |
| 1410 | IVC = 14 mbar, has risen significantly. Start pumping IVC with Scroll Pump. After 10 minutes, still stuck at 0.63 mbar. Stop pumping IVC. |
| 1420 | Fill LN2 cold trap bath |
| 1425 | Pump mixture out of cold LN2 Trap 1 into dump |
| 1440 | Pump mixture from fridge to dump |
| 1440 | MC(Cernox)/Sorb = 12.9/24 K |
| 1450 | Dump = 735.8 mbar and rising, looks like it would reach 736-7 if the pump were kept on longer. Close all the fridge and IVC valves and stop 3He pump. |
| 1455 | Matt exits lab |
| 1810 | MC(Cernox)/Sorb = 19/34 K |
| 1815 | IVC = 0.74 mbar. Why does it go up and down like this? |
| 2045 | MC(Cernox)/Sorb = 48/82 K |
| 2045 | IVC = 3.4 mbar. |