2021/05/03 (Monday)
- Lab in-person: Matt
- Virtual partner: Zach
| Status | Run 74 in progress. Warmed up after second occurrence of IVC leak during initial LHe transfer. Cryostat Vacuum Jacket pumping overnight. N2 in IVC. |
|---|---|
| 1250 | Matt enters lab |
| 1255 | MC(Cernox) = 281 K. |
| 1255 | Turbo on CVJ = 34 nbar. With Turbo valved out for 1 minute, CVJ = 630 nbar. Stop pumping CVJ. |
| 1300 | Stop pumping CVJ |
| 1300 | Check contents of warm LN2 Trap 1: 7.3 mbar. This trap was used during cooldown. Pump out with Scroll Pump |
| 1305 | Check contents of warm LN2 Trap 2: 5.7 mbar. Pump out with Scroll Pump |
| 1325 | Start cryocleaning mixture through cold LN2 Trap 1, V6 = 12.6% |
| pressure goes to high, close V6 - we'll try again | |
| 1330 | Reset V6 → 12.3% |
| 1335 | Increase V6 → 12.7% to restart flow |
| 1425 | Stop cleaning through Trap 1 after 60 min. G2 flow pressure was 585-790 mbar. Pump mixture to dump. Removed 5.3 mbar. |
| 1415 | Remove all MB bolts |
| 1420 | Remove covers from pit |
| 1425 | Lower MB into pit |
| 1440 | Tighten the 24 bolts at the top of the middle section of the IVC. They generally do have some give, some more than others. Two of them can't be tightened because the sockets are worn out. Should I swap these out? Or could removing them mess up the seal? |
| 1440 | Tighten the 6 bolts at the base of the stripline tube. These don't have much give. |
| 1505 | Replace the two bolts with worn-out sockets at the top of the middle IVC section |
| 1510 | Do two more rounds of tightening bolts at top of the middle IVC section |
| 1515 | Tighten the 16 bolts at the top of the top IVC section (at the brass fridge plate). Do a couple of rounds. Not as much give as at the middle section. |
| 1520 | Tighten the 24 bolts at the bottom of the IVC a couple of times. |
| 1525 | Remove covers from pit |
| 1535 | Raise MB and replace covers on pit |
| 1535 | Begin gently pumping IVC with Scroll Pump |
| 1545 | Start attaching MB bolts. This time I raised the MB until it was almost touching, then put in the two large bolts very loosely, then started with the small bolts. A little pushing around has got several of them started… |
| 1550 | Get all the small MB bolts started. Begin inserting medium bolts in the bottom. |
| 1550 | Switch to pumping MB with Turbo Pump |
| 1455 | Start cryocleaning mixture through cold LN2 Trap 2, V6 = 12.8% |
| 1505 | Increase V6 → 12.9% to restart flow |
| 1520 | Increase V6 → 13.0% to speed up flow |
| 1555 | Stop cleaning through Trap 2 after 60 min. G2 flow pressure was 590-690 mbar. Pump mixture to dump. Removed 4.5 mbar. |
| 1605 | Finish tightening all MB bolts |
| 1620 | Turbo on IVC = 74 nbar. With Turbo valved out for 1 minute, IVC = 740 nbar. |
| 1625 | Matt exits lab |