| 0955 | Attach SQUET on DIB4/Stripline 20. Electrical checkout is OK except SQUID C to chassis 10 MΩ leak, Feedback C to chassis 8 MΩ leak, and as we already know ~ 200 Ω leaks for QETs to chassis. |
| 1015 | Attach SQUET on DIB3/Stripline 27. Electrical checkout is OK except Feedback B to chassis 2.6 MΩ leak, and ~ 200 Ω leaks for QETs to chassis. Exception is QETC which has a higher resistance to chassis and to other QETs, 16 kΩ. This is the channel that sometimes read as open at detector level. But it's hard to understand this reading; if the channel is open now at the detector, we really shouldn't be able to tell because it's shorted by the shunt resistor (as long as one connection to the detector is OK). |
| 1100 | Begin sealing IVC |
| 1115 | IVC bottom screws are tightened most of the way. Begin gently pumping IVC with scroll pump. Opening pump valve slowly, in stages. Monitor on mechanical gauge (with valve to mechanical gauge open). Start at scroll pump ≈ 2“Hg below atm (0.93 bar) |
| 1125 | Scroll pump ≈ 3”Hg below atm (0.90 bar) |
| 1130 | Pumpout is failing, looks like Ebox seal wasn't done correctly. Open it again and check the o-ring… |
| 1145 | Reseal the Ebox (cleaned the flanges and put a little vacuum grease on the o-ring and seated it more carefully). Begin pumping with scroll pump, opening valve at pump in stages and monitoring pressure on mechanical gauge |
| 1150 | This time opening the valve a little causes a faster response on the gauge.
Scroll pump ≈ 4“Hg below atm (0.87 bar) |
| 1155 | Scroll pump ≈ 17”Hg below atm (0.43 bar). Pfeiffer gauge falls from 1 bar to 0.86 bar. Close green valve to mechanical gauge. |
| 1200 | Scroll pump = 2.5 mbar on Pfeiffer gauge. Open valve to scroll pump completely. |
| 1225 | Scroll pump = 0.12 mbar |
| 1300 | Scroll pump = 74 μbar. Begin pumping IVC with turbo pump. |
| 1315 | Turbo pump = 2.5 μbar. IVC > 100 μbar. |
| 1330 | Begin warming up leak detector |
| 1401 | Begin cryocleaning, V6 = 12.4%, adjusted to 12.9% |
| 1412 | Adjusted V6 to 13.0% |
| 1421 | Adjusted V6 to 13.1% |
| 1425 | Turbo pump = 0.54 μbar. IVC = 86 μbar. |
| 1425 | Begin pumping IVC with leak detector. LD was below 1 pbarL/s before opening valve, jumped to 20 pbarL/s after opening valve, then began to settle. |
| 1430 | LD signal has settled to 7.0 pbarL/s. A little higher than Run 63 but in that run we pumped overnight first, so probably comparable. |
| 1445 | Squirt-test leak check. Like last time we see leak near top of stripline tube, everywhere else looks OK. When squirting with no restriction from hose, get a peak around 80 pbarL/s. When using the hypodermic for more control, get around 2.2 pbarL/s peak. |
| 1500 | Like last time we'll try to live with this leak. It doesn't seem to have gotten worse. Last time I'd suggested trying to loosen the (upper) compression ring then retighten it, but that should have been tried before pumping out the IVC. Maybe next time.
Stop LD, resume pumping IVC with turbo pump. |
| 1530 | Raise main bath. Start attaching screws. |
| 1547 | End cryocleaning, close V14, V13b, V4. Open V9, V3. |
| 1610 | Turbo pump = 0.46 μbar. IVC = 34 μbar. Stop pumping IVC for now. |
| 1615 | Check pressure in cryostat vacuum jacket: 300 μbar. Start pumping cryostat vacuum jacket with scroll pump. |
| 1625 | Start pumping cryostat vacuum jacket with turbo pump. |
| 1626 | Close V12b and speedivalve, close V3, close V6 to 0%. Close V9 and close He3 pump. |
| 1640 | Turbo pump 2.5 μbar, cryostat vacuum jacket 120 μbar |
| 1655 | Finish tightening main bath screws. |
| 1700 | Turbo pump 1.2 μbar, cryostat vacuum jacket 86 μbar. Stop pumping vacuum jacket. This will probably be sufficient. |
| 1710 | Start pumping on IVC with turbo pump again, will pump overnight. |