We performed the measurement of the vibration spectrum using the 3axis accelerometer.
Totally, 10 position measurement were performed.
The summary will be appeared soon.
JGWDoc15750
1. The peaks around 30 Hz
The spectrum of geophone has large wide peaks around 30 Hz and the origin was unknown.
But in the spectrum measurement in accelerometer, we cannot detect any 30 Hz peaks.
So I suspect the some unique noise in geophone inside the OMC chamber.
2. The peaks around 225 Hz.
The relatively larger peaks detected in the range of 200-250 Hz in geophone.
Similar peak was detected in the position 1 (+X side of OMC)
There would be some materials which have the resonant frequency at 200 250 Hz.
3. The peak around 125 Hz
The relatively larger peaks detected in the range around 125 Hz in geophone.
The similar peak was detected in position 3,7,8,9,10.
Some origin exist in -X area?
4. Many peaks 150-200 Hz in position 2.
Many peaks around 150-200 Hz in position 2. Beam damper and/or steering mirror?