- The DCPDs whitening chassis was found to be switched to Low-Z - transitioned back to high-Z.
- We added notch filters for the 4.01Hz and5.01Hz SRM dither lines into the SRCLFF path. They are a Q of 60, 40dB deep. The high Q was picked to minimize the phase distorsion - it is actually slightly too high for the line width (which is driven by coupling fluctuation.) With this modification, the SRM alignment dither can be running in LOW_NOISE in case we need it.
- We also revived the pr2spotmove.py and pr3spotmove.py scripts (stored in /ligo/home/controls/sballmer/20160927/). They move the spot position on PR2 and PR3 respectively, leaving all other things equal. We were hoping to see a change in the auxiliary loop length noise - aspecially SRCL (they are higher than O1 - see Sheila's attachment.)
- First, we moved the pr2 spot position: (PR3 by 10urad in pit and 5urad in yaw). Next we did the same for the pr3 spot position (10urad on PRM). Unfortunately we did not see any change in the auxiliary loop noise.
Some additional notes: