Ryan, Lisa, Evan
We have been locked for more than 1 hour with CARM controlled by digital REFL9I (at 0 pm offset) and DARM controlled by ASAIR 45Q. The power buildup is 1100 times the single-arm buildup, giving an interferometer recycling gain of 33 W/W. The REFL_A_LF power is 1.35 ct, compared to 21 ct with the arms held off resonance. This means the interferometer visibility is about 94%.
The new element today was a higher-bandwidth DHARD pitch WFS loop. The loop time constant is a few seconds or so, and is fast enough to suppress the appearance of the microseism in ASAIR 45Q. Next steps are probably to close the analogous yaw loop. Ryan had to adjust ETM differential yaw by hand several times to keep the AS beam reasonably round. Also, Ryan had to add a DC-coupled oplev servo to ETMX L1 pitch in order to keep the optic from drifting.
Details will be posted later.