gabriele.vajente@LIGO.ORG - posted 15:47, Wednesday 06 March 2024 - last comment - 15:59, Wednesday 06 March 2024(76149)
Alignment notes
Elenna, Sheila, Gabriele, Jennie W et al.
- ran the TMS and ITM baffle alignment again, and reset the green camera offsets for the position we found in this way (see SDF screenshot)
- ran a full initial alignment and were able to lock PRMI and DRMI
- disabled DRMI ASC except for MICH
- disabled shuttering of ALS beam and SDF revert
- made it to PREP_ASC_FOR_FULL_IFO, lost lock due to 0.45 Hz instability in DARM.
- There was a lot of graound motion due to fire trucks and Jim took BRSX out of loop.
- Chnaged the order of offsets in ALS DIFF guardian to speed up FINDIR - this worked.
- The POPAIR checker goes to PRMI when it shouldn't.
- Lost lock at CARM OFFSET 5 pico m. REFL was 0.5 of unlocked power when locked, ARM TRANS was 800 x single arm which from plots linked implies PRG in mid-40s - good enough for locking.
NB: LHO alog 62110 shows PRG gain plots.
[Jennie W took this log over from Gabriele]
Images attached to this report
Comments related to this report
Matt and I checked on the POPAIR checker (added 70882). It was acting correctly, moving to PRMI when RF18 (not RF90) doesn't flash above 95 in the first minute.
Matt lowered the threshold to flashes of RF18 not above 80 in the first 120 seconds. This threshold should be rechecked once we are locking reliably.