gabriele.vajente@LIGO.ORG - posted 10:58, Friday 26 September 2014 (14169)
Expected powers and signals on ISS QPD and PDs
Peter K, Sudarshan, Gabriele
With 160 W of power at the input of the IMC we expect 125 W at the IFO input. The beam sampler in transmission of the IMC collects 300 mW, of which 250 mW goes into the ISS array.
Therefore, with the present 10 W at the IMC input, we should have 15.6 mW into the ISS array. Of this, 1% of 50% goes to the QPD, corresponding to 78 uW on the QPD, and 1.95 mW on each photodiode.
The signal on the QPD should be 75 uW x 0.75 A/W x 100e3 V/A = 5.5 V or 9100 counts
The signal on each photodiode should be 1.95 mW x 0.75 A/W * 1600 V/A = 2.4 V or 3900 counts