jenne.driggers@LIGO.ORG - posted 16:36, Sunday 27 October 2019 (52725)
Sunday locking
[Jenne, Chiara, Varun]
COMM beatnote is quite low (-18dBm). Going to do an initial alignment, and probably will also move IM3 as suggested by Georgia (alog 52710)
Set IM3's yaw slider to 4186, then ran through rest of initial alignment, except for SRY. SRY didn't want to lock, hand-aligning SRM (after having done the SR2 align state) made the fringes on the AS air camera look okay, so going to just try locking.
Didn't change PR3 (because we shouldn't need to), so COMM beatnote is still quite low, so it wasn't a problem with the ITM alignment. We'll see if the IFO locks, otherwise might have to move PR3 a bit.
COMM beatnote was fine (negative a few dBm) yesterday as of ~22UTC, but now it's not fine. Varun is checking if PR3 drifted or something, since none of the incursions to ISCT1 yesterday *should* have affected the beatnote path.
Ended up moving PR3 a small amount to get the COMM beatnote up to -14dBm, so that we could hold the COMM lock and go forward.
Broke lock at CARM_TO_REFL, not really sure why. (Skipped CARM_5_pm). Varun said that the PRG today was similar to yesterday's.
Holding at DRMI ASC Offloaded so Chiara can get some on/off data of ISI differential CPS of HAM4-HAM5 (separate alog on these results).
I have to go, so Varun will keep trying to re-lock.