I ran Jenne's rubbing script using a reference time of us being in DOWN on the 22nd before the fuzziness started on the 23rd around 07:00UTC and a check time of 10:00UTC on the 23rd while also in DOWN, I didn't really see anything noteworthy, some noise increase in the 0.1Hz area (microseism)?
I also ran using the same reference time against a time this morning and there was a couple of suspensions that looked interesting, there were some spikes in the 1.0 - 10 Hz bandwidth for PR2, PR3, PRM, SR3, SR2, MC3, MC1, and OM3. In the 0.0 - 1.0 bandwidth the Quads saw an increase in noise, specifically the ITMs, TMSs, and ETMY. SRM and SR2 have some large spikes just under 1 Hz. The ITMs temperature has slightly increased, ~ 0.25 - 0.3 degrees F but these changes are less than 0.5 degrees so its probably not a worry.
Later in the day I ran the script a 3rd time using a time from yesterday (13:54UTC 11/29) with the same reference from the 22nd and most of the features I saw are no longer there, except for ITMX. Maybe the time I chose earlier was just a bad time?
I checked the ISI motion on the ITMs, and ETMs using the BLEND GS13 channels. I also took a spectra of SRM and SR2. They all pretty much look as they did a month ago except SR2s low frequency noise is higher, 0.1 Hz and below.
I took raw osem spectra of all four QUADs (the 0.45Hz peak seen over here is a suspension mode - reference shown here) and Beam splitter and they look fine - please see the screenshot attached below. The measurements were taken when the IFO was in DOWN state.
Since we had time (like 5-10mins), I also took a quick transfer function measurements on ITMY - P (F1, F2, F3 BOSEM), T (SD BOSEM), V(LF, RTBOSEM) dof and they look healthy. ITMY has been restored to its nominal state after the measurements were complete.
Ibrahim is now trying to lock the IFO.
Since Jenne was concerned about SRM, SR2, SR3 and OM3 based on Ryan's plot above, I took raw osem spectra of the same and they look fine to me - see plot attached below. OM3 has a small peak at 2.28 Hz and at 40Hz approximately - which I am currently investigating by going back in time (update - similar features also visible when I run these measurements three weeks back in time).
I used dtt to reproduce Ryan's plot for SR2 using the gps times in his second pdf attachment. Looking at the DAMP in signals this reproduces Ryan's result. Looking at the individual osem signals (right colum plots), it looks like the problem is mostly visible in LF and RT osems.
Looking at a time series of the time from Ryan's second attachment, that is just a few seconds after a lockloss. So the alarming things that we are seeing are just ring downs of the lockloss transient.
