Sudarshan, Thomas, Darkhan, Travis, Rick

Summary

At 104.7. Hz the displacement DARM ASD was 1.26e-16 m/rtHz , the ASD according to the Pcal line was 2.07e-16 m/rtHz. The ratio is 1.64, with Pcal reporting a higher ASD.

Details:

We were running the Pcal calibration line at 104.7 Hz at LHO ENDY (25000 cts. excitation amplitude) during the lock stretch

After calibration of the power going to the test mass using the Working Standard at Yend and using the radiation pressure induced displacement equation

x= 2*P*Cos(theata)/M*c*(2*pi*f)^2

we have calculated (preliminary) the calibration value for the Transmission Monitor photodetector to be

x= 1.68e-12 (1/f^2)*(m/V)

Attached is the calibrated plot of Pcal ASD together with the DARM ASD in the region near the calibration line.