I spent most of today dodging the interferometer crew, as they're tasks have changed through the day, and installed ground STS to HEPI sensor correction. It runs, but I have had mixed results getting improvements out of it. I wanted to try this as it offloads some lower frequency Z isolation from the ISI, where it couples to RZ motion. I've had the  best results on ITMY, where Fabrice has installed RyanD's blend filters. The attached plots show what I've been able to get. ITMY_before_HEPI_senscor, shows the performance before turning sensor correction on, ITMY_after shows after, ITMX_before_blends shows the performance from 4 days ago, before any changes were made (the ISI was running our standard blends, with STS to St1 sensor correction, and position only loops on HEPI).  The first pages are a summary of the seismometer signals, page 2 is the oplev, page 3 is suspension point, and the rest are each of the plots from page 1 blown up.

As far as the ISI goes, pages 6 and 7 of  the attached files show the important stuff. Basically, we get good reduction in motion  above .1 hz and some amplification below, with ISI or HEPI sensor correction. I think we are doing better at ITMY now, although the oplev (page 2) seems to disagree with me, but the commissioners may have been doing something with the optic when I took that spectra. I'll be waiting with bated breath for the commissioners input, though.