Conclusion :
Chamber vibration may affect the OMC LSC control.
Should we measure the transfer function?
Memo :
In both sound and vibration injection, we can see the peaks in OMC LSC controls signals.
That imply the vibration of the OMC chamber affect to the OMC LSC control.
We injected five frequencies
89.0 Hz (reference)
89.6 Hz (Large DARM excess detected in previous study)
90.8 Hz (Large DARM excess detected in previous study)
91.1 Hz (Large DARM excess detected in previous study)
92.0 Hz (reference)
The amplitude for each frequency was almost same (From the signals of accelerometer on the OMC chamber)
There are also signal at the geophone inside the OMC chamber.
Imply there is the vibration path from OMC chamber to geophone (and OMC_LSC control)
The amplitude appeared in the OMC_LSC control is 92 Hz > 89 Hz.
If you have a good idea for additional measurement, please let me know, I tried to perform the measurement by finding the time.
The configuration :
IMC output 1.37 W
Xarm single lock (alignment is not so good(?))
Normarized Xarm transmittance power 0.88
ITMY misaligned
XARM guardian IR_LOCKED
OMC_ASC guardian OMC_QPD_CENTERED
OMC_LSC guardian OMC_LOCKED
Working log :
5:00 started the IRX lock trial and OMC alignment(used pico)
5:25 silent run
5:45 sound injection 89.6Hz 50 count
5:55 sound injection 90.8Hz 50 count
6:05 sound injection 91.1Hz 50 count
6:15 silent run
6:35 sound injection 91.1Hz 50 count
6:50 sound injection 92.0Hz 50 count
7:00 sound injection 89.0Hz 50 count
7:10 silent run
7:21 vibration injection 89.6Hz 200 count
7:29 vibration injection 90.8Hz 200 count
7:37 vibration injection 91.1Hz 200 count
7:45 vibration injection 92.0Hz 200 count
7:52 vibration injection 89.0Hz 200 count
8:00 silent run
8:20 finished
