Tonight I retuned the HAM1 feedforward, and I have included feedforward on all ASC loops that use the REFL WFS PIT: CHARD, INP1, PRC2, DC1 and DC2 P. So far there doesn't seem to be much gain to tuning yaw feedforward. The only loop I failed to implement feedforward to was DC2 (my code gave me filters that foton didn't accept, I will continue to work on this). There is now definite improvement in DARM with feedforward on, and the loops themselves show improvement in the error signals.

The goal of tuning other, lower bandwidth loops was to potentially further reduce the CHARD P noise. All of these loops are cross coupling, so I thought that some of the excess noise in CHARD P even after feedforward retuning was due to HAM1 motion coupling in through other loops. I also wanted to retune after IFO thermalization, to ensure that the IFO thermalizes into a better noise state. I started taking data about 7 hours into our lock.

The first attachment shows the improvement to DARM with feedforward on and off, and all the tuned loops with feedforward for that loop on and off. There is significant noise reduction 10-30 Hz in CHARD P, PRC2 P and INP1 P. There is minor improvement in DC1 P. The second attachment is a screenshot of the SDF in SEIPROC that accepts these new settings. I accepted the settings in OBSERVE.snap. The HAM1 feedforward will be turned on in lownoise ASC.

** There is a typo in my darm trace. The gray trace is CAL DELTA L feedforward ON, and the yellow trace is CAL DELTA L feedforward OFF