I want to redo this estimate of where RIN comes from, since Den did this measurement before I put the lens in front of the POP PD.
While thinking about his method of estimating the PR3 effect, I realized that we have measured numbers for the pendulum frequencies of the recycling cavity tip tilt suspensions.
I have been secreting this data away for years. My bad. The relevant numbers for Tip Tilts #2 and #3 were posted in elog 3425, and for #4 in elog 3303. However, the data for #s 1 and 5 were apparently never posted. In elog 3447, I didn't put in numbers, but rather said that the data was taken.
Anyhow, attached is the data that was taken back in 2010. Look to elog 7601 for which TT is installed where.
Conclusion for the estimate of TT motion to RIN - the POS pendulum frequency is ~1.75Hz for the tip tilts, with a Q of ~2. |