Find below range comparison screenshots between a low-range lock from 08/29/2024 after our emergency vent and a high-range lock from 06/17/2024.
Files live in:
/ligo/gitcommon/NoiseBudget/aligoNB/out/H1/darm_intergal_compare/compare_darm_spectra_OM2_hot_vs_cold_no_sqz.svg
/ligo/gitcommon/NoiseBudget/aligoNB/out/H1/darm_intergal_compare/compare_darm_range_integrand_OM2_hot_vs_cold_no_sqz.svg
/ligo/gitcommon/NoiseBudget/aligoNB/out/H1/darm_intergal_compare/compare_cumulative_range_OM2_hot_vs_cold_no_sqz.svg
/ligo/gitcommon/NoiseBudget/aligoNB/out/H1/darm_intergal_compare/cumulative_range_big_OM2_hot_vs_cold_no_sqz.svg
Plots were done using instructions from alog 76935 (+ help from TJ)
Here are some notes about what is limiting at low frequency:
I ran some coherences of the ASC yesterday during the lock. Top left plot shows DHARD to DARM coherences. There is a broadband DHARD Y coherence up to 60 Hz, which I think means we should retune the Y2L gains. See this comment: 79776
Top right and bottom left show CHARD and INP1 coherences to DARM. This is occurring strongly between 10-30 Hz, which I think is a sign the HAM1 FF is no longer performing well. I am working on tuning a new feedforward that we can test.
Finally, the bottom right shows CHARD/PRCL. I included this because it is on my to-do list to tune a PRCL feedforward. Up to 60% of the PRCL noise is coming from CHARD Y. I note this because usually HAM1 FF doesn't do so well for the yaw DOFs, but maybe the PRCL FF will help the CHARD Y/DARM coherence.
