Reports until 22:25, Wednesday 24 May 2023
H1 ISC
sheila.dwyer@LIGO.ORG - posted 22:25, Wednesday 24 May 2023 - last comment - 17:57, Friday 26 May 2023(69903)
suggestions for locking after EQ

We are still having difficulties with SRY locking, but I haven't looked into what is going on.  If SRY is not locking in an inital alignment step, it is OK to run SR2 ALIGN offload, and move SRM by hand to increase the SRY flashes. 

Editing to add:

Input align wasn't working well because of an apparent dark offset in POP A 45I.  I adjusted the dark offset from -68.9 to -72 to get the signal without flashes to be near zero.  This must be reset by one of the init align guardian states.  This problem has been seen before and TJ attempted to fix it here, but something is still not working.

2nd edit:  We weren't able to get above 30 counts on POP18 + POP90 in PRMI with PR3 at 151.6 yaw slider, so we moved it to 150.2 with the renormalizations above and re did initial alignment of the IR cavities.  Input align wouldn't lock but the flashes were at 1, so we moved on.  SRY has worked twice in a row.  With this lower beatnote we've had an ALS lockloss, I think that if a few more tries at this alignment aren't fruitful it would make sense to cancel the owl and go to the table in the morning.

Comments related to this report
jeffrey.kissel@LIGO.ORG - 17:57, Friday 26 May 2023 (69947)
In the end the PR3 and ISCT1 table alignment was a temporary fix for the true problem. The true problem was that the HAM-ISIs were all drifting off in Yaw (RZ) slowly, but surely, for weeks -- see LHO:69934.