2025/04/03 04:58:00 - 05:30:00 Silent run
2025/04/03 05:31:00 - 05:51:00 Speaker injection OMC area
Excitation : K1:PEM-EXCITATION_SR3_RACK_6_EXC
50 - 900 Hz white noise injection 1,500 cnt
Fig.1. showed the DARM sensitivity and microphone at OMC
2025/04/03 05:53:00 - 06:11:00 Speaker injection OMC area
Excitation : K1:PEM-EXCITATION_SR3_RACK_6_EXC
50 - 900 Hz white noise injection 500 cnt
Lock loss happened during this measurement (Tagged 1 Hz)
2025/04/03 06:43:00 - 07:03:00 Speaker injection OMC area
Excitation : K1:PEM-EXCITATION_SR3_RACK_6_EXC
50 - 900 Hz white noise injection 3,000 cnt
SRM tripped during this measurement, so I set SRM with SAFE state
2025/04/03 07:03:00 - 07:23:00 Silent run
2025/04/03 7:23:30 - 07:53:30 Speaker injection OMC area
Excitation : K1:PEM-EXCITATION_SR3_RACK_6_EXC
50 - 200 Hz , 1Hz resolution, 10 s in each measurement, 100 cnt
Fig.2. showed the whitening spectrogram
2025/04/03 7:55:00 - 08:25:00 Speaker injection REFL area
Excitation : K1:PEM-EXCITATION_MCF0_RACK_14_EXC
50 - 200 Hz , 1Hz resolution, 10 s in each measurement, 100 cnt
Fig.3. showed the whitening spectrogram
2025/04/03 8:28:00 - 08:38:00 Speaker injection OMC area
Excitation : K1:PEM-EXCITATION_SR3_RACK_6_EXC
82.0 Hz 100 cnt
2025/04/03 8:39:00 - 08:49:00 Speaker injection REFL area
Excitation : K1:PEM-EXCITATION_MCF0_RACK_14_EXC
116.0 Hz 100 cnt
I analyzed the OMC acoustic injection data:
2025/04/03 05:31:00 - 05:51:00 Speaker injection OMC area
Excitation : K1:PEM-EXCITATION_SR3_RACK_6_EXC
50 - 900 Hz white noise injection 1,500 cnt
- Fig.1: Spectrograms for the strain, the microphone, the geophone, the OMC error signal, and the square of the OMC error signal
- Fig.2: ASDs of these channels, for the reference and the injected time
- Fig.3: Microphone -> Geophone coupling and projection
- Fig.4: Microphone -> OMC error coupling and projection
- Fig.5: Geophone -> OMC error coupling and projection
Because any significant excess was found in the OMC error signal limited by its sensing noise, a noise projection on the strain was impossible.
I also analyzed the swept-sine OMC acoustic injection data:
2025/04/03 07:03:00 - 07:23:00 Silent run
2025/04/03 7:23:30 - 07:53:30 Speaker injection OMC area
Excitation : K1:PEM-EXCITATION_SR3_RACK_6_EXC
50 - 200 Hz , 1Hz resolution, 10 s in each measurement, 100 cnt
- Fig.1, 2: Spectrograms for each channel
- Fig.3: Microphone -> Strain noise projection using the response function model
- Fig.4 (PDF): Each single frequency injection
The noise excesses in the strain at the double of the injected frequencies are not so large, but they around the injected frequencies are significant.
The projected noise below 150 Hz is close to the current sensitivity. It was not evaluated well in the previous test (klog31563, 2024-11-09) but is well evaluated now, probably thanks to the IFI STM jitter noise that has been hunted.
The projected noise over 200 Hz is also getting closer to the sensitivity than before, but it can be thanks to the sensitivity improvement by the laser power up, because the projected noise level itself looks not changed so much.
Comparison between 2024-11-09 (klog32386) and 2025-04-03 (klog33220).
Note that I just used the 'K1:CAL-CS_PROC_DARM_STRAIN_DBL_DQ' channel's data written in the full-frame files and the calibration status was not cared.
Analysis result for
2025/04/03 8:39:00 - 08:49:00 Speaker injection REFL area
Excitation : K1:PEM-EXCITATION_MCF0_RACK_14_EXC
116.0 Hz 100 cnt
