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Reports until 13:08, Tuesday 09 May 2023
H1 ISC (SQZ)
camilla.compton@LIGO.ORG - posted 13:08, Tuesday 09 May 2023 - last comment - 00:38, Wednesday 10 May 2023(69441)
SQZ Angle change added to THERMALIZATION Guardian. Will change from 165 to 145 deg in first 90 minutes.

I have added sqz angle adjustments to the THERMALIZATION guardian that Gabriele made to servo the PRCL gain (alog 68948). SQZ angle will be adjusted from 165 to 145 degrees over the first 90 minutes of the IFO's lock. This is based on the SQZ Angle Adjustments tests in alog 69055.

In the SERVO_PRCL_GAIN state of the THERMALIZATION guardian, just before SQZ is injected, H1:SQZ-CLF_REFL_RF6_PHASE_PHASEDEG will be set to 20 degrees (SQZ_CHANGE) higher than nominal. Over 90 minutes (SQZ_THERM_TIME), the angle with be linearly taken to 145 degrees (sqzparams.SQZ_ANGLE). Adjustments to final sqz angle should be saved to /sqz/h1/guardian/sqzparams.py as SQZ_ANGLE and THERMALIZATION reloaded (only reload during lockloss).

Hope that this will increase H1 range at the start of the lock, if this isn't the case, we can revert these changes.

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camilla.compton@LIGO.ORG - 14:58, Tuesday 09 May 2023 (69451)

Due to a typo in the guardian code, I restarted the THERMALIZATION guardian so that the SERVO_PRCL_GAIN actually started 5 minutes later than it should have done for this lock.

victoriaa.xu@LIGO.ORG - 00:38, Wednesday 10 May 2023 (69464)

Given the recent update of the SRCL offset to -290 this past week (69402), it looks like our ideal squeeze angle when thermalized has changed quite a bit from before, when Camilla found a good squeeze angle for that IFO configuration. Here are trends of rotating the sqz angle a bit, watching the 1.3kHz ADF line phase-rotate (oops, we should probably look at the ADF magnitude, ie the IQ_RMS, as well; that will tell us if we're "squeezing" at the ADF frequency), the sqz blrms, and the range. We will probably want to update the "thermalized" angle in sqzparams.py.

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