Reports until 16:48, Friday 04 July 2025
LHO General (SQZ)
ryan.short@LIGO.ORG - posted 16:48, Friday 04 July 2025 - last comment - 17:32, Friday 04 July 2025(85550)
Ops Eve Shift Start

TITLE: 07/04 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Commissioning
OUTGOING OPERATOR: Tony
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 25mph Gusts, 20mph 3min avg
    Primary useism: 0.04 μm/s
    Secondary useism: 0.07 μm/s
QUICK SUMMARY: H1 has been locked for almost 11 hours, but currently not observing as I'm troubleshooting an issue with the SQZ filter cavity. I'm able to consistently bring everything with the squeezer up to before the FC is needed, and lock the FC up to the SQZ_FC Guardian's 'IR_FOUND' state, but every time I try moving on, the FC drops out. Investigation still ongoing.

Comments related to this report
ryan.short@LIGO.ORG - 17:32, Friday 04 July 2025 (85551)SQZ

H1 back to observing at 00:18 UTC.

Ultimately, after trying several things that didn't completely fix the issue like trending FC1/2 OSEMs, adjusting FC1/2 to maximize FC green transmission, and doing a "graceful clear history" on the filter cavity ASC, I enlisted Sheila for guidance. I ran her new 'SCAN_OPOTEMP' Guardian state to optimize the OPO temperature (then gave it a couple more steps to maximize CLF_REFL_RF6), then requested SQZ_MANAGER all the way up to 'FREQ_DEP_SQZ', which worked perfectly this time. The improvement of CLF_REFL_RF6 from 0.35 to 0.39 must have been just enough to make the filter cavity happy.

There were outstanding SDF diffs on h1ascsqzfc, possibly from my history clearing, which Sheila said were okay to just revert (screenshot attached). When I did this, I saw the green FC spot wobble, but not unlock. I then returned H1 to observing.

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