Sheila, Elenna

We took measurements of the dark signals on the REFL A/B and AS A/B WFS yesterday and compared them with measurements from May 4, 2021 when the IFO was locked. See the attached plots. Each plot compares the locked and dark state for sensors for REFL and AS sensors in A and B, in I and Q and PIT and YAW. It appears that we are becoming dark noise limited around 20 Hz, and maybe even slightly before for some of these sensors. We are not sure if this ADC noise or electronics noise. We will investigate that next.