Com'on. This is just a 60ppm change of the mod frequency from the nominal. How can it change the recycling cav length by more than a cm?
https://wiki-40m.ligo.caltech.edu/IFO_Modeling/RC_lengths
This describes how the desirable recycling cavity lengths are affected by the phase of the sidebands at non-resonant reflection of the arms.
If we believe these numbers, L_PRC = 6.7538 [m] and L_SRC = 5.39915 [m].
Compare them with the measured numbers
- Lprc = 6.752 m
- Lsrc = 5.474 m
You should definitely run MIST to see what is the optimal length of the RCs, and what is the effect of the given length deviations. |