camilla.compton@LIGO.ORG - posted 15:44, Monday 03 August 2026 (91371)
SQZ OMC Scans and M^2 Measurements with new ZM4 ZM5 PSAMS Preloadings
Sheila, Ryan S, Camilla
We spent the morning repeating 90783, now that ZM4 preloading has been adjusted (90951) and ZM5 has been swapped and now has a different preloading than our O4 ZM5 (91292):
- Using SQZ ASC with ZM4 and ZM5 to get ASC_A and ASC_B centered, we needed to move SRM to stop saturating ZM4/5,
- then locking OMC on 00 touching up OMC and OM3 alignment to maximize 00 peak,
- then putting these ASC-OMC offsets into H1:OMC-ASC_QPD_A/B_PIT/YAW_OFFSET so that the OMC ASC will put us in this good location.
Sheila then used her script to run OMC scans at a grid (below) of PSAMS locations. These initially look great, showing sqz to omc mode mismatch is as good as 1%. with some alignment fluctuations. Ndscope of data taking attached.
PSAM_VALUES_V5 = [-8, -5.5, -3.3, -1]
PSAM_VALUES_V4 = [-3.2, -1, 1.2, 3.4]
Ryan then took M^2 measurements on SQZT7 of a slightly different grid:
PSAM_VALUES_V5 = [-8, -6.75, -5.5, -4.5, -3.3, -1]
PSAM_VALUES_V4 = [-3.2, -1, 1.2, 3.4]
Images attached to this report
