Dhruva, Camilla, Vicky

Summary: We got up to 3dB FDS in the IFO! After some IFO-SQZ aligning, Dhruva locked FC on IR WFS-LSC, and got quiet time to get the clean blue trace! Compared to freq-indepdent (no-FC) squeezing, FC seems to boost sensemon range ~16MPc. Interesting to compare 3dB-FDS vs. first 2dB-FDS in Dec.

Notes from today's tests while getting back up to 3db sqz in ifo. We started with NLG ~ 8.

• How close does IFO-ASC (based on AS42) bring you to optimal sqz-ifo alignment? So far, we've seen ASC can bring it within like ~0.5-1 dB of our optimal ~3dB sqz, so it's a helpful starting point for ifo alignment. To evaluate,
     1) we turned ON the AS42 ASC, measured SQZ (dark blue/gray trace),
     2) went to ASQZ, offloaded ASC by moving ZM5(pos)/ZM6(ang) P/Y sliders to zero the outputs (SQZ-ASC_POS/ANG_P/Y_OUTPUT), then turned OFF ASC.
     3) "aligned" the squeezer from the ASC spot, by maximizing OMC_TRANS_RF3 and asqz, saw a bit more asqz ths way, not sure if this alignment is done yet. (light purple asqz trace)
         -- now we're using ~10dB asqz w/NLG~8.2. we've sometimes used slightly more before, but we need to turn up input IR to SHG.
     4) back to SQZ (w/asc still off, same slider values), then took the blue trace.

Tracking GRD issues as we go:

• SQZ_MANAGER sometimes randomly requests SQZ_READY_HD. Hard to track when it happens and why, we've added a "10" on the grd path from LOCK_CLF --> SQZ_READY_HD, but not sure if this has fixed it yet. Keep an eye out for this..
• SQZ_MANAGER - needs to start controlling SQZ_FC. Even for freq-INdep sqz: Hold FC on "GR_LOCKED" off-IR-resonance while when ttfss beatnote dies. When beatnote drifts away, then unlock FC+(CLF+LO), then relock FC+(CLF/LO). It happens that CLF drifts through FC resonance, which in turn can kick the CLF/LO loops.
• LOCKED_OMC does not wait for SQZ-PSL beatnote to settle near 160MHz before trying to relock
• OPO_GRD + CLF_GRD are both ready to use their respective ISS's. To use their ISS, enable their use_iss flags to True in guardian code. Currently both flags are false (guardians do not engage ISS's atm).