Robert, Anamaria

Yesterday during the commissioning period I was running some tests at low frequency from the control room and Robert went in to look into a HAM5 viewport (for OFI issues). During my tests I noticed several times that the 82ish peak in DARM went very high, possibly excited by viewport activites. I attach here a spectrogram that shows the 82Hz and the closest HAM5 accelerometer. We lost lock a minute or two after this time. Some of the ring-ups line up with some of the accelerometer disturbances, but not all. Perhaps if we go through several of the chamber accelerometers, we could find one that lines up with all of them and better triangulate where the 82 Hz is coming from.