**SRM Calibration**
After the DRMI measurements on Friday, SRY cavity was locked in order to compare ITMY and SRM actuators.
SRY cavity was locked with AS55Q -> SRM servo with gain of +10?
(My memory is fading. I tried +50 and noticed it was saturated at the limiter. So I thought it was 10)
Then the transfer functions between SRM->AS55Q TF and ITMY->AS55Q TF were measured.
The ratio between two transfer functions was obtained as seen in the second attachment.
The average at f<100Hz was 4.07 +/- 0.15. Therefore the calibration is ... as you can find below
SRM: http://nodus.ligo.caltech.edu:8080/40m/10664
**SRM = (19.0 +/- 0.7) x 10 **^{-9}/ f^{2}
PRM: http://nodus.ligo.caltech.edu:8080/40m/8255
**PRM: (19.6 +/- 0.3) x 10**^{ -9} / f^{2} m/counts
BS/ITMs http://nodus.ligo.caltech.edu:8080/40m/8242
**BS = (20.7 +/- 0.1) x 10**^{ -9} / f^{2} **m/counts**
ITMX = (4.70 +/- 0.02) x 10 ^{-9}/ f^{2} **m/counts**
ITMY = (4.66 +/- 0.02) x 10 ^{-9}/ f^{2}** m/counts** |