chandra.romel@LIGO.ORG - posted 11:45, Friday 12 May 2017 - last comment - 16:14, Friday 12 May 2017(36159)
Vertex vacuum pressure and other updates
- Current vertex pressure is 1.0e-5 Torr at BSC2 (2.8e-6 Torr at turbo)
- Vertex turbo is being backed by scroll pump
- QDP80 turned OFF - back filled with room air
- Opened leaky GV on IP1 (IP OFF) after verifying pump side pressure (e-3 Torr range)
- Leak checked X-beam manifold some more this morning - checked all flanges/viewports/camera housings on reducer flange near GV7. Then sprayed He in bag for about 15 minutes before running out of He. Left leak checker running for about 2 hours after that with no detected He signal
- Leak checked the two conflats on HAM2 that were removed during vent - no leaks
- X-beam manifold turbo station is OFF (not de-energized yet though)
- Monitoring GV4 annulus which is being pumped by aux turbo cart (pumping away excess He from leak checking)
- Aux carts on HAM4 and BSC3 doors are decoupled
WARNING: don't turn on high voltage until pressure reads e-6 Torr range on PT-120B gauge
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A reminder - Paschen's curve of breakdown voltage vs pressure. And note that we have gaps at feedthroughs in the mm range rather than cm.
From Wikipedia;
https://en.wikipedia.org/wiki/Paschen%27s_law
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GV4 annulus vacuum is surviving on the IP alone at 5 mA. I left the turbo hardware connected, but everything is powered OFF.
Valved out water from QDP80 pump and turned booster pump off. Left x-beam manifold turbo station energized until I leave site.
Vertex turbo inlet pressure is 2.1e-6 Torr. BSC2 pressure is 7.9e-6 Torr.