While LLO was relocking this morning, I dropped observing from 13:44 to 13:54 UTC to run Gabriele's MICH FF template with 35 averages.
The measurement is saved in /ligo/home/ryan.short/MICH_excitation_2023_07_20.xml
Using this measurement, I retuned the MICH FF. The new filter is FM6 '7-20-23'. The attached plots show the fit and a comparison of the performance of the new filter and the old. There's a lot of improvement above 60 Hz, and a few db improvement below 60 Hz
I've accepted the new FM6 filter in SDF as well as updated and loaded ISC_LOCK to use this filter when locking.
Here's a plot showing the DARM improvement with the new MICH FF, that gave us about +6 Mpc
Here's a second iteration of the MICH FF, with much better performance below 60 Hz and marginally worse above 60 Hz. I think this is a better FF, so we'll leave it running as FM7 '7-20b-23'. ISC_LOCK has been updated
Here is a different view of the impact of Gabriele's MICH FF tuning this morning. Seafoam and purple are the same as in alog 71529, and red is today after the MICH FF tuning. All of these are with hot OM2 and no MICH ASC offsets. Seafoam is late June, purple is yesteray, and red is today. Red only has 94 averages because there were other commissioning tasks ongoing, but the other two both have 200 avgs.
The MICH FF tuning got us all the way back to where we were in June, with the excellent ~70 Hz sensitivity. There is still some jitter-like noise, but that is unchanged from yesterday.
