aLIGO LHO Logbook

LHO General

thomas.shaffer@LIGO.ORG - posted 07:30, Thursday 20 November 2025 - last comment - 09:01, Thursday 20 November 2025(88184)

Ops Day Shift Start

TITLE: 11/20 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 6mph Gusts, 4mph 3min avg
Primary useism: 0.02 μm/s
Secondary useism: 0.30 μm/s
QUICK SUMMARY: Locked for 6 hours but it looks like the squeezer has an issue. Working on it now. Dust alarm in the diode room, but other than that, no alarms overnight.

Comments related to this report

thomas.shaffer@LIGO.ORG - 07:56, Thursday 20 November 2025 (88185)

Link

Notifications from the SQZ suite of guardians:

SQZ_MANAGER - request Reset_SQZ_ASC_FDS

SQZ_OPO_LR - "pump fiber rej power in ham7 high, nominal 35e-3, align fiber pol on sqzt0."

SQZ_LO_LR - "LOW OMC_RF3 power < -22! Align SQZ-OMC_RF3, or more CLF power if aligned."

This seems like a similar situation as alog87361

thomas.shaffer@LIGO.ORG - 09:01, Thursday 20 November 2025 (88186)

Link

I ended up doing these things:

Cycling SQZ_MANAGER Down and back. Same results
Setting SQZ_OPO_LR to Scan_OPOTEMP
Adjusting the SHG rejected fiber power with the half and quarter wave plates, but I wasn't sure that I was actually making anything better. While I was reducing the SQZ-SHG_FIBR_REJECTED_DC_POWERMON from 0.75 down to near 0.1 (the guardian notification says it should be around 0.035), the H1:SQZ-SHG_REJECTED_DC_POWERMON was still drifting away at the same rate. I ended up reverting these changes.
At this point the only SQZ guardian notification was the SQZ_LO saying that their might be a misalignment issue since there was no 3MHz a the OMC. Sheila walked in and moved ZM4 and ZM6 back to a time when we had a better sqz lock. This went away.
Squeezing still looks back, but Sheila says the angle is bad and it might have to do with her script from last night. She touched that up and we were back.