J. Kissel

Taking the data from this afternoon's aLOG as my target frequencies (LHO aLOG 40534), I've tuned BRD S/Ns 014 and 018 to match the highest vertical (a.k.a bounce) and roll mode frequencies of the newly suspended H1 SUS ETMY. Results are attached and tabulated below:

    'Target [Hz]'    'BRD S/N'    'Mean Fit Freq. [Hz]'    '% Diff [%]'
    '9.734'          '014'        '9.792'                  '0.59'      
    ''               '018'        '9.76'                   '0.26'      
    ''               ''           ''                       ''          
    '13.843'         '014'        '13.811'                 '0.24'      
    ''               '018'        '13.876'                 '0.24'

The uncertainty in the frequency corresponds to the original binwidth of the measured vibrometer / QPD data, +/-15 mHz.

Setup for measurement is as described in the HAM ISI TMDs (see LHO aLOG 38741) using corroborating evidence from both the laser vibrometer and a primitive shadow sensor setup. To calculate the above "Mean Fit Frequency," I used a least square's minimization with a Lorentzian seed function,
    fit(f) = (1/Q)^2 ./((f - f0).^2 + (1/Q)^2) + C 
to fit both sensors' data to obtain the measured frequency within the noise, and then took the mean of the two sensors' results.
The mean frequencies are less than 1% different from the target frequency of H1 SUS ETMY, which means the tuning is within requirements of "match target frequency to better than +/-1%."

I've left the tuned valentines on Betsy and Travis' desk.