J. Kissel, K. Izumi, S. Karki

I've culminated the results of the three different measurement techniques for determining the actuation strength of all three stages of ETMY, 
- Laser Wavelength: Free-swinging Michelson LHO aLOGs 18718
- Voltage Controlled Oscillator: ALS DIFF VCO LHo aLOG 18711
- Photon Radiation Pressure: Photon Calibrator LHO aLOG 18758 (Only for ETMY L3)
The numbers quoted below are what will be used in DARM model we'll use during ER7, which we'll then use to update the GDS pipeline and CAL-CS models.

    'Optic'      'Weighted Mean'    '1-sigma Uncertainty'    '1-sigma Uncertainty'
    'Stage'      '[m/ct]'           '[m/ct]'                 '%'                  
    'ETMY L1'    '5.12e-11'         '8.6e-13'                '1.7'                
    'ETMY L2'    '6.97e-13'         '1.2e-14'                '1.8'                
    'ETMY L3'    '6.07e-15'         '1.4e-16'                '2.4'                
    'ETMX L3'    '3.56e-13'         '8.2e-15'                '2.3'

See attached for a graphical representation of how the individual results compare against the weighted mean and uncertainty (Wikipedia).

Recall that all of these numbers' uncertainty arises from either the statistical uncertainty of the individual measurements which compose the result (i.e. the coherence of the transfer function), or a compression of each frequency point in a TF into one number via weighted means and uncertainties. In no way have we accounted for systematic uncertainty other than comparing using the three different methods (for ETMY L3 at least). Very encouraging that they agree to within 2.5%!

We have enough data to propagate PCal's number for L1 and L2 of ETMY, but we've just run out of time. However, we've found that with the other two methods (Free-swinging MICH, and ALS DIFF) that the L1 and L2 stages agree with the dead-reckoned model to within 4%, and we don't at all expect these actuators to be varying with time like we do the ESD stages.

Note that the ratio between EX and EY's ESDs confirms the factor of ~50 that was needed when scaling EX to EY during the initial attempts to relock the IFO with the low noise driver.

Further, it's encouraging to see that three measurement techniques each of which take several hours (save PCAL) taken over the course of a few days. I'm still not convinced that the actuation strength didn't actual increase between the FS MICH and ALS DIFF measurements (since they're all systematically higher), but we just need more data to confirm. However, now that we trust that PCAL agrees with ALS DIFF and FS MICH, we can focus our energy on PCAL. Surdarshan's working on grabbing past lock stretches from the frames and assessing how this coefficient has varied over time.