As Q mentioned in elog 10527, (prompted by Koji's email this afternoon) we are prepping the IFO for vent. Here is a copy of the pre-vent checklist from the wiki, updated as we work:
1 & 2: Locked arms on IR, ran ASS. Unlocked IFO, aligned PRM for good POP flashes, aligned SRM for symmetric AS flashes. Aligned all oplevs. Used PZTs to align Xgreen to arm. Used knobs to align Ygreen to arm. With PS:L green shutter closed, Xgreen = 0.520, Ygreen = 0.680.
3: Moved MC servo output cable that goes to ADC from OUT2 (which we had been using for monitoring AO path signals) back to its usual OUT1 (which is MC_L). This is used in the spot position measurement script. Spots at: [2.32, -0.50, 1.97, -1.11, 0.26, -1.86] mm.
4: Done -Q
5: Removed a PD that was monitoring the light coming backwards through the Faraday that sits just after the laser, just in case (confirmed that beam dump behind PD was catching beam). Other port of PBS just had regular black hole dump. Adjusted half wave plate until we had ~90mW just before injection into the vacuum.
6: Completed. Locked MC manually at transmission of ~1150, but low power autolocker isn't working. This isn't a critical thing, and can be fixed at any point during the vent. -Q
7: Shutters closed. Ready for Steve to check nuts and begin venting! -Q