SudarshanK, RickS

We completed calibration of the Pcal power sensors at EndY today using the new Working Standard (WSH). This calibration also incorporates the changes we made to the Pcal Tx and Rx  power sensors on Tuesday (LHO  alog 45876). The results of this set of endstation calibration measurements can be found in the attached text file.

All the data, plots and the intermediate results from this calibration measurement can be found at https://svn.ligo.caltech.edu/svn/aligocalibration/trunk/Projects/PhotonCalibrator/measurements/LHO_EndY/D20181213/

Using these measurements plus the Working Standard to Gold Standard responsivity measurements, new Gold Standard measurement from NIST (-8.0985 V/W) and the in-vacuum optical efficiency measurements we did during the vent, the force coefficients for the Pcal TxPD and RxPD in N/V are:

TxPD : 1.5049E-09 N/V

RxPD: 1.0223E-09 N/V

The previous values used during O2 and still implemented in the filter files are: 

TxPD : 1.5160e-09 N/V

RxPD: 1.0475E-09 N/V

They differ from these new values by about 0.7 and 2.4%, respectively.

We are not going to update the calibration at this time. We will wait until the next long lock opportunity to test the new values by comparing with X-End Pcal.

The parameter file that is required to generate the force coefficient in the front model is attached as well. Note: We have left the TX and RX (AA) gain factor as 1.