Experimental Investigation of Operating-Point Offsets in the Angular Automatic Control System of Gravitational-Wave Detectors

The data used in this study mainly consist of three parts: first, the amplitude spectral density of the WFS signal measured under different phase-plate conditions while a 40 Hz angular excitation was applied to the ITM; second, the equivalent angular noise ASD used to evaluate the angular sensitivity of the system and the contributions from different noise sources; third, the mean values of the WFS signal as a function of phase-plate transverse position during lateral scanning.