camilla.compton@LIGO.ORG - posted 12:14, Tuesday 16 July 2024 - last comment - 13:39, Tuesday 16 July 2024(79169)
High DARM coherence with LSC: Feedforward re-tuning needed
We ran the coherence plot (instructions in LowRangeChecks wiki) for 2024/07/16 18:47 UTC with reported 132MPc, plot attached. See lots of coherence with SRCL, PRCL, MICH so we plan to re-tune these feedforwards. The CHARD coherence <15Hz isn't new but the coherence around 30Hz is, it might be coupling through the LSC loops though.
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After turning SRCLFF gain down from 1.14 to 1.0, the coherence looked a lot better and the range increased to 145MPc.
We took FF measurements for SRCL, MICH and PRCL, saved to /opt/rtcds/userapps/release/lsc/h1/scripts/feedforward. Before fitting these we found we didn't like this IFO alignment (79172).