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Reports until 10:38, Tuesday 24 June 2025
H1 SUS
jeffrey.kissel@LIGO.ORG - posted 10:38, Tuesday 24 June 2025 (85277)
H1SUSSRM Transverse <-> Side OSEM2EUL / EUL2OSEM Elements Changed to +1.0
J. Kissel

Following LHO:85198, I've changed the sign the OSEM2EUL and EUL2OSEM matrix elements that transform from "SD" to "T" and vice versa, as SRM is one of the few HSTSs that have their "SD" OSEM mounted on the "Opposite Side," (again see G2402388 and E1100109).
    Matrix Element                  Was     In now
    H1:SUS-SRM_M1_OSEM2EUL_2_6      -1.0    +1.0
    H1:SUS-SRM_M1_EUL2OSEM_6_2      -1.0    +1.0

I attach a comparison two sets of new health check TFs, one UNDAMPED and the other DAMPED against a previous 2024 measurement. This metric (and any other metric we have) shows no change, as expected (see "Shouldn't we have discovered this with the 'health check TFs?'" section of LHO:85198).

The SUS was in the new "HEALTH CHECK" guardian state, but with the alignment offsets ON*** and all DOF's worth of damping loop gains set to -0.5 per nonimal since 2023 (see LHO:85273). 
The ISI/HEPI system was isolated, but with sensor correction OFF because it's maintenance day.
*** "It is known" that in the current mechanical alignment vs. OSEM position, that with the alignment offsets OFF, the LF and RT OSEMs aren't far above ADC 0 counts, and thus the magnitude of the TFs drops by almost a factor of two, and coherence gets worse even with twice the excitation amplitude.

I also attach SDF screenshots of me accepting these new values in the safe and OBSERVE .snap files.

The data sets are committed to
    /ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/SRM/SAGM1/Data/
        2025-06-24_1558_H1SUSSRM_M1_WhiteNoise_L_0p02to50Hz.xml
        2025-06-24_1558_H1SUSSRM_M1_WhiteNoise_P_0p02to50Hz.xml
        2025-06-24_1558_H1SUSSRM_M1_WhiteNoise_R_0p02to50Hz.xml
        2025-06-24_1558_H1SUSSRM_M1_WhiteNoise_T_0p02to50Hz.xml
        2025-06-24_1558_H1SUSSRM_M1_WhiteNoise_V_0p02to50Hz.xml
        2025-06-24_1558_H1SUSSRM_M1_WhiteNoise_Y_0p02to50Hz.xml

        2025-06-24_1629_H1SUSSRM_M1_WhiteNoise_L_0p02to50Hz.xml
        2025-06-24_1629_H1SUSSRM_M1_WhiteNoise_P_0p02to50Hz.xml
        2025-06-24_1629_H1SUSSRM_M1_WhiteNoise_R_0p02to50Hz.xml
        2025-06-24_1629_H1SUSSRM_M1_WhiteNoise_T_0p02to50Hz.xml
        2025-06-24_1629_H1SUSSRM_M1_WhiteNoise_V_0p02to50Hz.xml
        2025-06-24_1629_H1SUSSRM_M1_WhiteNoise_Y_0p02to50Hz.xml
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