Our range is very low even with squeezing (about 130 Mpc). There seems to be some problems with squeezing, but there is significant jitter coherence from 10-40 Hz that is abnormal. The noise on the IMC WFS has increased by about 2x at low frequency, but decreased at high frequency, so there is much more power on them now. Sheila trended IMC refl and MC2 trans and IMC refl is higher than normal, MC2 trans is lower than normal. We can also see that the MC refl camera "looks different" (calling this "tea leaf reading"). The PRCL and SRCL coherence is also much higher than normal.
"It just looks like there is not much squeezing"- Sheila
We've tried some different things to move the IMC alignment around, but nothing seems to be working and we are tired. Our plan is to come back to this in the morning.
We think that something from today's power outage has caused these problems, but we are not sure what.
Screenshots include:
low range coherence check from Ibrahim
IMC WFS spectrum comparison (blue is yesterday, red is now)
sqz comparison change this also shows that squeezing is not causing the low frequency extra nosie
Here is a longer measurement of the IMC WFS and LSC coherence with calib strain. I can't get the coherence to run with calib strain clean right now. I'm not sure how good the cleaning is performing, but I do know that the strain and clean channels looks slightly different bove 100 Hz, so some jitter is being removed.
looking at IMC REFL DC, at 2W was 60% higher after the power outage than before, MC2 trans is lower by 2% than before the power outage.
At 60W input power, IMC REFL is 190% of what it was before the power outage, MC2 trans is 96% of what it was.
We trended MC suspensions and PZT drive, the suspension are within the range of where they were before the power outage but the PZT is different. We tried opening the PZT loop (MC2 trans to PZT), increasing the MC WFS gain from 0.04 to 0.16, and walking the PZT offet. It seemed like moving this in either direction in yaw made things worse, moving the pZT back towards it's old position in pitch also made things worse.
One suspicion could be that the beam from the PSL has shifted in alignment.