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Entry  Mon Jul 11 11:56:40 2022, he Yehonathan, Update, BHD, MICH AS55 noise budget Control_Diagram.pdfMICH_AS55_Noise_Budget.pdf
    Reply  Tue Jul 12 09:14:50 2022, rana, Update, BHD, MICH AS55 noise budget 
       Reply  Wed Jul 13 10:54:39 2022, Yehonathan, Update, BHD, MICH AS55 noise budget BS_MICH_ACtuation_Calibration.pdfMICH_AS55_Model_Measurement_Comparison.pdfMICH_AS55_Noise_Budget.pdf
          Reply  Wed Jul 13 13:30:48 2022, Yehonathan, Update, BHD, add Laser RIN to MICH budget 
             Reply  Mon Jul 18 16:49:57 2022, Yehonathan, Update, BHD, add Laser RIN to MICH budget Laser_RIN.pdfMICH_AS55_Noise_Budget.pdf
                Reply  Mon Jul 18 18:33:38 2022, Koji, Update, BHD, add Laser RIN to MICH budget 
Message ID: 16989     Entry time: Tue Jul 12 09:14:50 2022     In reply to: 16984     Reply to this: 16996
Author: rana 
Type: Update 
Category: BHD 
Subject: MICH AS55 noise budget 

Looking good:

  • I think the notches you see in he measured noise are a clue as to the excess noise source. You can try turning some notches on/off.
  • Laser noise does matter a bit more subtley: the low freq noise couples to AS55 through the RMS deviation of the MICH loop from the zero crossing, and the noise of the 55 MHz modulation.
  • Jitter in the IMC couples to MICH through the misalignment of the Michelson.
  • As you rightly note, the optical lever feedback on the ITMs and BS also make length noise through the suspension actuator imbalance and the spot mis-centering.
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