TITLE: 05/24 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:

IFO is in ENGINEERING and DRMI has Locked! IFO is in DOWN until Tues.

The relock acquisition today was a success! While the expectation was to get through ALS before facing issues, we managed to lock DRMI and get all the way to CARM_TO_REFL (state 409).

Of note is that the BS is slightly off in that when we do lock DRMI, the AS camera shakes for a bit and the POP90 trace gets very noisy emulating the jitter almost. I can see as this is happening, F2 and F3 OSEMs are saturating indicating something off in the MICH length loop. Elenna lowered the gain slightly and while this allowed us to get past the DRMI state, it came back upon passing that state 409. As the PR_GAIN is ramping up, the trace either jitters before losing lock or it just loses lock very instantly. The current hypothesis is that this is something to do with the BS particularly in the MICH Length Loop.

For some reason, in our most recent lock attempt, the issue did not happen with the only configuration difference being that the WFs centering was turned on and correct. However, we still had that sudden lockloss at CARM_TO_REFL so the issues may not be related.

See Elenna's alog 84569 for details on tonight's recovery and lock reacquisition.

Other:

DC centering loops on the input matrix for the REFL WFs were flipped and oddly saturating RM2. Elenna discovered this after some troubleshooting and unflipped it - they were SDF accepted s well.

LOG:

None