J. Kissel In order to assess the performance of the recently installed "Level 2.1 design" of the HLTS damping loops (design: G1400151, which is just a pointer to LLO:7907, installation: LHO:64152), I've taken the standard "health check" transfer functions, but comparing with these new damping loop filters ON vs. OFF. (This test is more comprehensive and easier to interpret than a step-function / ring-down test, so we therefore won't need to do those test). Comparing the attached pages of today's results against the plum-colored, dashed, "MIMO Closed loop / 100" traces on pages 4, 11, 18, 25, 32, and 39 for L, T, V, R, P, and Y respectively, shows that the loops work as designed, and we get the expected amount of Q reduction for all resonances in all DOFs, while achieving much better sensor noise rejection about ~10 Hz. Nice work Elenna and Evan! Measurement details will be posted in the comments.
The raw data for these two measurements can be found here: /ligo/svncommon/SusSVN/sus/trunk/HLTS/H1/PR3/SAGM1/Data/ 2022-08-02_2008_H1SUSPR3_M1_WhiteNoise_L_0p01to50Hz.xml # Undamped 2022-08-02_2008_H1SUSPR3_M1_WhiteNoise_P_0p01to50Hz.xml 2022-08-02_2008_H1SUSPR3_M1_WhiteNoise_R_0p01to50Hz.xml 2022-08-02_2008_H1SUSPR3_M1_WhiteNoise_T_0p01to50Hz.xml 2022-08-02_2008_H1SUSPR3_M1_WhiteNoise_V_0p01to50Hz.xml 2022-08-02_2008_H1SUSPR3_M1_WhiteNoise_Y_0p01to50Hz.xml 2022-08-02_2041_H1SUSPR3_M1_WhiteNoise_L_0p02to50Hz.xml # Damped 2022-08-02_2041_H1SUSPR3_M1_WhiteNoise_P_0p02to50Hz.xml 2022-08-02_2041_H1SUSPR3_M1_WhiteNoise_R_0p02to50Hz.xml 2022-08-02_2041_H1SUSPR3_M1_WhiteNoise_T_0p02to50Hz.xml 2022-08-02_2041_H1SUSPR3_M1_WhiteNoise_V_0p02to50Hz.xml 2022-08-02_2041_H1SUSPR3_M1_WhiteNoise_Y_0p02to50Hz.xml Because the undamped transfer functions are the same as our "health check" transfer functions, I post here the processed data for the individual measurement that shows off-diagonal cross-coupling and OSEM basis response.