Jenne, TJ, Sheila, Naoki,
We looked at some trends together of what's been happening with H1's range, PRG, and various sensors related to the PRC over the last few months.
The first screenshot here shows some of these trends, with the first horizontal cursor showing, Oct 24th a day when we had a particularly good BNS range just above 160 Mpc. The vertical cursors are set to show a reference of what the various signals were on that good day. Some things to notice:
I do not believe we have any sensors that are more stable than just relying on the mechanical stability of the suspensions themselves. In the past, all our attempts to stabilize the uncontrolled dof in the IMC have produced worse results than relying on the stability of its suspensions.
Naoki, Sheila
We looked at some spectra comparisons. In both attached screenshots the references are the 160+ mpc time from Oct 24th. The first one shows the good time from Oct 24th compared to a time when the DARM noise was high due to clipping from Nov 29th. This shows features that have been aloged else where, the yaw ASC loops have excess noise 74502, the coherence of LSC and ASC POP is high and the ASC pop signals have extra noise (74580). There isn't as dramatic a difference in the LSC signals, which are measured in the path that was clipped, which is interesting.
The second attachment is a comparison to after our recent PR3 moves, motived by wondering if some small amount of remaining clipping could explain why our sensitivity isn't as good as it was in October. The noise of the POP sensors and the coherence of LSC and ASC POP are similar now to the time of our best range, so there isn't any obvious indication here that we are still clipping.