2021/11/23 (Tuesday)
- Lab in-personnel: Matt
| Status | Beginning Run 75. |
|---|---|
| 1K Pot isolated. MB raised. Cryostat vacuum jacket (CVJ) pumped out. | |
| Yesterday I found 79 mbar in LN2 Trap 2 from last week's cryocleaning, that's extremely high. Let's check Trap 2 to see if anything leaked in overnight. | |
| 1115 | Check contents of warm LN2 Trap 2: 2.5 mbar. Not very high, if there's a constant leak it's slow, not enough to explain the high Monday reading. Pump out with Scroll Pump. The base pressure during pumping suggests there was only 1.5 mbar in the trap. (Really it probably makes more sense to use the difference between before-and-after pumpout rather than our usual, before-and-after opening V12a/b.) |
| 1120 | Check contents of warm LN2 Trap 1: 1.2 mbar. Also low. Pump out with Scroll Pump. While pumping pressure falls by 0.7 mbar. |
| 1130 | Start cryocleaning mixture through LN2 Cold Trap 2, V6 = 12.5% |
| 1135 | Increase V6 → 12.6% to speed up flow |
| 1155 | Increase V6 → 12.7% to restart flow |
| 1225 | Increase V6 → 12.9% to restart flow |
| 1235 | Stop cleaning through Trap 2 after 65 min. G2 flow pressure was 570-675 mbar. Pump mixture to dump. Removed 6.6(5.6) mbar. |
| 1255 | Start cryocleaning mixture through LN2 Cold Trap 1, V6 = 12.8% |
| 1305 | Increase V6 → 12.9% to restart flow |
| 1320 | Increase V6 → 13.0% to speed up flow |
| 1400 | Stop cleaning through Trap 1 after 65 min. G2 flow pressure was 590-7005 mbar. Pump mixture to dump. Removed 5.2(4.0) mbar. |
| 1610 | Check contents of warm LN2 Trap 2: 6.6 mbar. Pump out with Scroll Pump. While pumping pressure falls by 5.6 mbar. |
| 1615 | Turn off 3He pump. |
| 1630 | Check contents of warm LN2 Trap 1: 5.2 mbar. Pump out with Scroll Pump. While pumping pressure falls by 4.0 mbar. |