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Entry  Mon Apr 16 15:35:15 2012, Frank, Tara, Summary, NoiseBudget, mechanical resonances beatboard_resonances.jpgPDH.jpg
    Reply  Mon Apr 16 18:17:05 2012, Frank, Tara, Summary, NoiseBudget, mechanical resonances 
Message ID: 918     Entry time: Mon Apr 16 15:35:15 2012     Reply to this: 920
Author: Frank, Tara 
Type: Summary 
Category: NoiseBudget 
Subject: mechanical resonances 

we mapped the mechanical resonances in our system using two techniques :

  1. tapping each optical component and check spectrum for excited modes. This technique is difficult as we usually excite a lot of other mechanical modes nearby as well.
  2. exciting everything with white noise (loudspeaker) and then add damping on individual components and checking spectrum which modes we reduce. Very precise but you have to start with the dominant wants and damp them first to see the smaller ones nearby.

resonance frequency is attached to each component. Green background behind numbers means we could verify the frequency using both techniques. Yellow means measured using tapping but could not see using the damping technique as the contribution to the beat signal is to weak. Input optics needs to be checked and finalized. Picture is temporary only.

beatboard_resonances.jpg PDH.jpg

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