[Yuzurihara, Washimi, Ushiba, Komori]
We created the noise budget for O4a using Pastavi.
https://dac.icrr.u-tokyo.ac.jp/KAGRA/DAWG/Detchar/klog/klog26086
The dominant noise sources are as follows.
- 10-60 Hz: Suspension local control noise (klog:25784). The control noises from SR3 and BS have been reduced by optimizing the feedback filter (klog:26016).
- 60-400 Hz: Sum of the acoustic noise from various locations (klog:25790). Some contributions from each location might be double-counted, leading to a possible overestimation.
- 400 Hz-1.5 kHz: OMC DC PD dark noise and the shot noise (klog:25787).
- 1.5-7 kHz: Frequency noise (klog:25979).
The local control noise can be reduced by implementing better filters.
The acoustic noise improves with the square root of the input power if it behaves like a sensing noise.
To address the PD dark noise, cabling improvements are required (klog:25965).