| | Status: IVC sealed and turbo pumping overnight. Main bath vacuum jacket is evacuated. 1K Pot needle valve closed. LN2 traps clean. Mixture is in dump, fridge evacuated. |
| 0930 | Turn on leak detector |
| 1100 | Turbo pump = 46 nbar, IVC = 1.0 μbar |
| 1110 | Do electrical check on all three DIBs, for phonon-related (including cross-channel connectivity) and LEDs. All look fine. |
| 1110 | Leak detector background signal with it valve closed is 1.2 pbarL/s. |
| 1115 | Stop pumping IVC with turbo, start pumping with LD. Signal flattens at 5.5 pbarL/s. Better than Run 59, Run 60, and Run 61, although in Run 61 we did not turbo pump overnight so it's probably comparable. |
| 1445 | LD pumping on IVC, background 4.3 pbarL/s. Begin squirt tests. |
| 1500 | Leak seen at top of “wizard staff”, signal rises to 10 pbarL/s. |
| 1530 | Trying to tighten compression ring which tightens the stripline elbow o-ring onto the wizard staff. It's hard to budge. It could loosen a tiny bit, and this seemed to improve the leak slightly. Borrowed the smaller pipe wrench from the student shop and was able to work it onto the knurled compression ring - messing with this caused a sudden big leak, up to 100,000 pbarL/s - then came back down again. Tried a second time, tightened it slightly, leak shot up to about 1,000 pbarL/s, came down again. |
| 1630 | Will probably give up trying to improve this seal and try to live with the leak. It's still peaking at around 10 pbarL/s, which is pretty low. We may want to pump continuously on the IVC during the run. Between runs we should try loosening and retightening this seal. |
| 1650 | Experimented a little more: holding the elbow up from below makes the leak worse, around 100 pbarL/s. Pulling it down makes it better. I tried wedging some strips of aluminum between the elbow and the fridge flange above it to hold the elbow down - this may have helped a little but didn't have much effect. Leak is still around 10 pbarL/s. |
| | No leaks seen elsewhere with squirt tests. |
| 1700 | Stop leak checker, return to turbopumping IVC. |