| Status | Run 76 ending |
| Setup | DCRC33(2)→HV control, NaI trigger signal → DCRCX(4) |
| | Warming up. Turbopumping IVC overnight (for more leak checks). Mixture in dump. Warm LN2 Trap 1 clean. NaI array removed and stored in LIGO lab. Lead/poly shield removed. Clean tent erected at bottom of fridge. |
| 1411 | turbo on IVC = 0.86 ubar. Start up leak detector |
| 1413 | LD on IVC baseline is about 170 pbarL/s, higher than yesterday. (Although I left the valve to the mechanical gauge open overnight, that explains the high Turbo pressure and maybe explains this higher signal. |
| 1430 | Tried messing around with the stripline elbow while watching the leak signal. When the elbow was raised by prying open the space between the compression rings, the signal shot up to something like 2000 but then relaxed again. Pushing back and forth didn't cause any changes. I was going to try loosening and retightening the ring but I couldn't manage to loosen it. |
| 1435 | Start slowly letting N2 gas into IVC. |
| 1450 | Turns out it's much easier to tighten or loosen the compression ring on the elbow and to move it up or down, tilt it left or right when the IVC is at 1atm. But we'll stop messing with leakchecks now and instead begin opening the IVC. |
| 1450 | Start removing bottom piece of IVC. |
| | Thinking about the stripline elbow leak and the fact that the seal seems to stay OK for maybe a year after replacing the o-ring, then it goes bad. Could the thermal cycling of the o-ring cause it to lose elasticity over time? Here's an article discussing how weather impacts o-rings. It lists some materials that are resistant to cold cycling - the material we've been using (viton, aka FKM, aka fluoroelastomer) is not in that list, so maybe it's susceptible to cold cycling. Two materials they say are resistant to cold cycling and also to degradation from moisture are 1) ethylene propylene (EPR) and 2) nitrile. |
| 1512 | Start removing Squets from 4K stage, looking at the squets I didn't see anything wrong (thinking of the HV shock which might have damaged them)
    |
| | A heatsink fell out when removing screws, it looks like the copper wires came loose
 |
| 1548 | Deinstall 4K stage (I took the 2nd picture after I took out a heatsink from the 100mK stage)
  |
| 1605 | Deinstall 100mK stage |