Summary
This is the data analyzed from last week's end-station Pcal readout calibration. The new calibration factors will be used to compare with the old calibration factors. The calibration factor currently used will only be updated if there is a significant change.
Details:
The calibration factors obtained from this particular measurement are tabulated below. The number in parenthesis is the weighted mean of our past calibrations that we have been using in our current calibration model. The new factors are comparable with the past measurements in most cases.
| RxPD (N/V) | TxPD (N/V) | |
| CAL-PCALX | 1.062E-09 +/- 0.85% (1.053E-09) | 1.317E-09 +/- 0.85% (1.322E-09) |
| CAL-PCALY | 1.053E-09 +/- 0.65% (1.059E-09) | 1.519E-09 +/- 0.65 % (1.520E-09) |
The RxPD at ENDX shows a difference of about ~1% from our currently used calibration. We think this is because there might be some beam clipping issue again that we have seen in the past in this particular unit. The drop in optical efficiency, seen in the attached report, and the trends of the RxPD signal both point in this direction. We don't have major calibration lines running in this unit( there is a high frequency (3KHZ ) line only). Additionally, we also have a TxPD readout that we can use if we show the clipping is happening on the way out, after reflecting off the testmass, which we think is the case. There are ways to check this and we are pursuing those cross-checks.
All the data and plots have been updated to the svn and more details about the intermediate factors used during the calculation, optical efficiency etc is attached with this alog.
The summary page (T1500252) on DCC that keeps track of these calibration factors has also been updated.
