ryan.crouch@LIGO.ORG - posted 07:27, Wednesday 11 December 2024 - last comment - 12:52, Wednesday 11 December 2024(81758)
OPS Wednesday DAY shift start
TITLE: 12/11 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 156Mpc
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 5mph Gusts, 3mph 3min avg
Primary useism: 0.03 μm/s
Secondary useism: 0.32 μm/s
QUICK SUMMARY:
- We've been locked for 14:20, in observing since 03:33
- 2ndary microseism is decreasing, its just below the 90th percentile
- Low wind
I ran the lowrange coherence check for a good and bad range time during this current lock.
I looked through the suspension driftmon scopes from the medm IFO_ALIGN_COMPACTEST and most looked normal compared to other locks. The main thing I saw that looked strange was a small step in MC3_P at the same time as the range gets better, I didn't see this behaviour in previous locks with bad range stretches though.
I looked at the OPLEV BLRMS as well, the main thing I saw on these scopes was that the BSs BLRM increased, largely in yaw, during the bad range times of this current lock. I don't see as obvious of a jump in other lock stretches.
Jenne suggested that we look at top mass Vertical osems to check for sagging that is causing touching. I check the quads, BS and output arm and see no drifts that correlate with the low range periods.
I looked at verticals for MC{1,2,3}, PR{M,2,3}, and FC{1,2} and the only thing I odd I noticed is that FC2 vertical seems to move more during the bad range times than the good range. Most of them see a seasonal small downward sag over the past 40 days.
I've looked at spectra (using 64 sec of data split into 16 second chunks with 50% overlap) of the top mass osems for all suspensions, comparing between start times of 1417933576 (bad time) and 1417950319 (a little while after the sharp improvement). None of the spectra have any of the classic 'we're rubbing' peaks. I've noted a few that I want to re-plot and zoom in (RM1 L, RM2 L, OMC L P V, FC1 P Y R T). I'll also re-look at MC3, since that one is one of our most 'suspicious' optics right now.
I attach the spectra that I made, of these potentially suspicious optics. The main conclusion here is that none of these are actually very suspicious, so since these are my *most* suspicious, probably we are not rubbing. But, I'll make a few more plots of these suspensions. In all of these plots the blue 'reference time' is when the IFO is locked with good sensitivity, and the orange 'check time' is when the IFO is locked with poor sensitivity.
I replotted the 'suspicious' top mass spectra using DTT. I don't find anything suspicious or interesting on FC1 or MC3.
OMC is a little strange, in that it has a set of peaks that all change frequency in the same way (first attachment). I'm not sure that this is meaningful for today's investigation though.
RM1 and RM2 are both quite strange looking in the 5-9 Hz range. They both pick up a forest of peaks in Length (and a little bit in Pit, and maybe a teeny bit in Yaw). Second attachment. Going to look further into these, maybe at other times as well. Robert said that these both saw some motion on the summary page, but their motion didn't seem to correlate with the reduction in range.