We looked at the time series for all the oplevs except the BS, from last Tuesday night, during a time when we were building up the power in the arms. We conclude from a 400 second stretch of data that there is not discernible difference in the amount of motion of any optic, when the cavities are at medium power, and when they're at low power. Note however, that we don't have such a nice stretch of data for the really high powers, so the maximum arm power in these plots is around 5. Both the TRX and TRY signals look fairly stationary up to powers of 1 or 2, but once you get to 4 or 5, the power fluctuations are much more significant. So, since this isn't caused by any optic moving more, perhaps it's just that we're more sensitive to optic motion when we're closer to resonance in the arms.
However, from this plot, it looks like the ETMY is moving much more than any other optic. On the other hand, ETMY has not ever been calibrated (there's an arbitrary 300 in there for the calibration numbers on the ETMY oplev screen). So, perhaps it's not actually moving any more than other optics. We should calibrate the ETM oplevs nicely, so we have some real numbers in there. ETMX also only is roughly calibrated, relative to the OSEMs. We should either do the move-the-QPD calibration, or a Kakeru-style pitch and yaw some mirrors and look at transmitted power.
Traces on this xml file have been filtered with DTT, using zpk(,[0.03],1,"n").