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fabian.arellano - 17:34 Tuesday 20 August 2019 (10052) Print this report
Optic residual motion on 16th of August 2019.

On Friday 16th of August I measured the residual motion of the optic in ALIGNED state. There was a typhoon in the neighborhood.

In the ALIGNED state the optic longitudinal RMS displacement and velocity DO NOT fulfill the requirement. Additionally, the yaw displacement seemed to be smaller in bad weather conditions. 

This table shows the integrated RMS displacement for each degree of freedom and the requirement.

Degree of freedom ALIGNED Requirement klog 9703
Longitudinal displacement  0.48  µm 0.4 µm  0.25 µm
Longitudinal velocity  0.62 µm/s 0.5 µm/s   0.3 µm/s
Pitch displacement  0.24 µrad 1 µrad  0.17 µrad
Yaw displacement  0.40 µrad 1 µrad  0.42 µrad

Relevant notes:

  • There's no Inertial damping.
  • There's high coherence with the IP motion measured with the LVDTs from 0.190 Hz up to 0.4 Hz. See plots attached.
  • With IM-L there's coherence at 0.4 Hz and 0.7-ish Hz.
  • With IM-P there's coherence at 0.4 Hz, 0.5-ish Hz and 0.7-ish Hz

Other notes

  • Directory: /kagra/Dropbox/Subsystems/VIS/TypeBData/SR2/Noise/Measurements/20190816/
  • File for ALIGNED state: SR2_ALIGNED_TM_OPLEV_ASD_190816_1565940276.xml
  • Bandwidth of the displacement measurement' from 0.010 Hz to 800 Hz.
  • The bandwidth of the optic velocity measurement was from 0.010 Hz to 10 Hz. Above 10 Hz there is a lot of noise which I don't believe is real displacement of the optic. The peaks are likely related to the oplev optics support platform
  • Related entries: 9703.
Images attached to this report
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