It would be interesting to know if the scattering seen at EY is new. Last October I did a quick set of injections to look for major problems - because of limited time these were speaker injections instead of shaker injections and did not probe much below 30 Hz. We did not see any coupling in October. Kara and I went out last night to reproduce the October injections to see if we would have seen vibration coupling if it were at the same level as it is now. The figure shows that we probably wouldnt have noticed the current level of coupling with the injection made in October.

We are set up so that a shaking injection can be made using H1:PEM-EY_GDS_1_EXC. I suggest a standard injection using a bandpass of 1-100 Hz and 50,000 counts for studies to reduce coupling by moving the RMs, offsetting the dither, etc. I have to leave, but Kara is familiar with the system.

Robert, Kara