Jax, sheila

The power out of the green laser has dropped to around 9mW, (12mW after adjusting the temperature and diode current), while there were  42.5mW a few weeks ago . Jax and I tried restoring the laser to  these settings  and saw that there were only 9mW coming out of the laser.  (jax has now set the crystal temp back to 32.8C, the way we found it)

The IR power out of the laser seems to explain the drop.  Using the values from   this alog , if nothing other than the IR power had changed we would have (22.9/(1125)^2)*(800^2)=11.6mW of green.  

On the reflected PD, we only measured 10uW, I am not sure if there have been some changes to the table layout that have reduced that power even further.    

I originally went to the end station to calibrate the green laser power PD, it is a PDA100A (transimpedance 1.5x10^4 Ohm on the 20dB gain setting), the responsivity I measured after realigning it was 0.687A/W. The PD is on one of the beams rejected by the faraday, there are 197uW on the PD when there are 12mW transmitted by the Faraday so the splitter ratio for this PD is 1.6%.  Since there is only 10uW on the LSC PD, I couldn't calibrate it.