[Rana, Jenne]
I took POP QPD calibration data with a new method, on Rana's suggestion. I locked the PRMI, and engaged the ASC servo, and then used awggui (x8) to put dither lines on all of the PRMI-relevant optic's ASCPIT and ASCYAW excitation points. I then took the transfer function of the suspensions' oplev signals (which are already calibrated into microradians) to the POP_QPD signals (which are in counts). This way, we know what shaking of any optic does to the axis translation as seen by the POP QPD. We can also infer (from BS or PRM motion for PR3, and ITMX motion for PR2) what the folding mirrors do to the axis translation. Note that we'll have to do a bit of matrix math to go from, say, PRM tilt effect to PR3 tilt effect on the axis motion.
The data is saved in /users/jenne/PRCL/July152013_POP_TFs.xml . There is also a .txt file with the same name, in the same folder, listing the frequencies used by the awg.
I'll analyze and meditate tomorrow, when my brain is not so sleepy. |