chandra.romel@LIGO.ORG - posted 14:22, Thursday 18 May 2017 - last comment - 18:16, Thursday 18 May 2017(36265)
opened GV 1,2
Around 1:30 pm local time, Gerardo and I opened GV 1,2 slowly by ramping up to 500 rpm, 800 rpm, 1200 rpm, finally 1700 rpm. Note that the gate annuli were pumped out before opening. GV2's volume was sustained by its AIP alone. GV1 needed help from aux turbo cart.
GV 5,7 are LOTO.
All ion pumps are ON and valved out, except IP1 which is OFF because its isolation GV leaks (valve open).
Check list before opening GV 5,7:
- Valve in IPs
- Turn IP1 ON
- Collect RGA scan
- Pump out GV gate annuli
Pump down curves so far
We gain about a factor of 10 by valving in ion pumps and cryopumps (via opening GV 5,7). For example, if we open GVs at 2e-7 torr, we should expect to see a drop to 2e-8 Torr. The pressure at BSC2 was 5e-9 Torr before we vented.
Turbo inlet pressures after opening GV 1,2:
X: 1.4e-7 Torr
Y: 2.4e-7 Torr