camilla.compton@LIGO.ORG - posted 13:20, Wednesday 03 January 2024 - last comment - 15:05, Wednesday 03 January 2024(75151)
OPO Tempurature and ADF Angle Phase Changed
As Naoki did in 75023, with SQZ_ANG_ADJUST in DOWN, I adjusted OPO temperature and H1:SQZ-ADF_OMC_TRANS_PHASE to improve SQZ in the yellow BLRMs (350Hz region). Our SQZ angle has changed from 167 to 180degrees. Since I did this the servo moved the angle away from and back towards this optimum 180degrees, will continue to watch.
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BLRMs 350Hz and below improved from this change. Other BLRMs remained the same. The change in SQZ angle was from Jenne's adjustments in OMC QPD offsets, effecting the SQZ ASC (expected) and then the SQZ angle servo.
Plots of SQZ angle and SQZ ASC attached.
When I changed the OPO temp and SQZ angle, the AS42_SUM_NORM almost halved, unsure if that is expected (see upper left of plot).
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