I ran A2L while we were still thermalizing, might run again later. No change for ETMY but the ITMs had large changes. I've accepted these in SDF, I reverted the tramps that the picture shows I accepted. I didn't notice much of a change in DARM or on the DARM blrms.
ETMX P
Initial: 3.12
Final: 3.13
Diff: 0.01
ETMX Y
Initial: 4.79
Final: 4.87
Diff: 0.08
ETMY P
Initial: 4.48
Final: 4.48
Diff: 0.0
ETMY Y
Initial: 1.13
Final: 1.13
Diff: 0.0
ITMX P
Initial: -1.07
Final: -0.98
Diff: 0.09
ITMX Y
Initial: 2.72
Final: 2.87
Diff: 0.15
ITMY P
Initial: -0.47
Final: -0.37
Diff: 0.1
ITMY Y
Initial: -2.3
Final: -2.48
Diff: -0.18
I am not sure how the A2L is run these days, but there is some DARM coherence with DHARD Y that makes me think we should recheck the Y2L gains. See attached screenshot from today's lock.
As a reminder, the work that Gabriele and I did last April found that the DHARD Y coupling had two distinct frequency regimes: a steep low frequency coupling that depended heavily on the AS A WFS yaw offset, and a much flatter coupling about ~30 Hz that depended much more strongly on the Y2L gain of ITMY (this was I think before we started adjusting all the A2L gains on the test masses). Relevant alogs: 76407 and 76363
Based on this coherence, the Y2L gains at least deserve another look. Is it possible to track a DHARD Y injection during the test?
Since I converted this script to run on all TMs and dofs simultaneously, its performance hasn't been stellar. We've only run it a handful of times, but we definitely need to change something. One difference between the old version and the new is the frequencies the injected lines are at. As of right now, they range from 23-31.5Hz, but perhaps these needs to be moved. In June, Sheila and I ran it, then swapped the highest frequency and the lowest frequency to see if it made a difference (alog78495) and in that one test it didn't seem to matter.
Sheila and I are talking about the AS WFS offset and DHARD injection testing to try to understand this coupling a bit better. Planning in progess.