J. Kissel

Using the refined H1 SUS BS OPTICALIGN alignment offset slider calibration (see LHO aLOG 14321), I've refined the calibration of the optical levers using the same method as with the ITMs (see LHO aLOG 14312), by moving the well-calibrated sliders and tracking the optical lever motion. Attached are the fitted slopes to this motion, which indicate that the new optical lever calibrations should be 

BS P     141 [urad/ct]
BS Y     231.9 [urad/ct]
as with the ITMs, Pitch has been corrected by a factor close to 2, where yaw needs only a ~15% correction.

Because the optical lever damping is actively used, I'll wait until tomorrow morning to install the new calibrations and adjust the loop gains accordingly.

Details:
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- Step through several alignment offset values (in [urad]), record DC optical lever output (in ["urad"], the quotes indicating the to-be-refined units). I chose to get a smattering of offsets between +/- 20 [urad] surrounding the currently saved "ALIGNED" values.
- Fit slope of data points to a line (see attached). The calibration corrections are
       ["urad"/urad]    [urad/"urad"]
BS P        1.901           0.526
BS Y        1.156           0.8654

         Previous Cal  *  Correction          = New Cal
BS P   268 ["urad"/ct] * 0.526 [urad/"urad"]  = 141   [urad/ct]
BS Y   268 ["urad"/ct] * 0.8654 [urad/"urad"] = 231.9 [urad/ct]