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Entry  Tue Feb 25 00:00:01 2014, rana, jenne, Update, LSC, reasons that the REFL signals may be degenerate now 
    Reply  Tue Feb 25 02:46:38 2014, rana, jenne, Update, LSC, Changing PRCL offset changes REFL 165 degeneracy PRC_offsetCheck_24Feb2014.pdf
       Reply  Tue Feb 25 14:48:49 2014, ericq, Update, LSC, Changing PRCL offset changes REFL 165 degeneracy MICHvPRCLangle_wOffset.pdfSBprclPeaks.pdf
          Reply  Tue Feb 25 16:07:33 2014, ericq, Update, LSC, Changing PRCL offset changes REFL 165 degeneracy MICHvPRCLangle_wOffset.pdfMICHvPRCLangle_wOffset_fullscale.pdf
             Reply  Wed Feb 26 01:49:08 2014, Jenne, Update, LSC, Changing PRCL offset changes REFL 165 degeneracy DemodPhaseSeparation.pdfPOP_AS_PDvalues.pdf
Message ID: 9668     Entry time: Tue Feb 25 00:00:01 2014     Reply to this: 9669
Author: rana, jenne 
Type: Update 
Category: LSC 
Subject: reasons that the REFL signals may be degenerate now 

We're exploring some effects which may give some funny macroscopic detuning and cause a near phase degeneracy in the REFL RF signals (see radar plot from Jenne below).

1) Alignment: we centered the oplevs to reduce fluctuations and then tweaked the BS and PRM alignment to build up the power. No significant change in the RF phases of the DOFs.

2) Measuring RAM: we set the dark offsets (by hand since the Masayuki script doesn't really work well anymore) to with 1 counts. We then locked the MC, misaligned the ITMs, and looked at the REFLOUT16 channels using the following command line:

z avg 12 C1:LSC-REFL11_I_OUT16 C1:LSC-REFL11_Q_OUT16 C1:LSC-REFL33_I_OUT16 C1:LSC-REFL33_Q_OUT16 C1:LSC-REFL55_I_OUT16 C1:LSC-REFL55_Q_OUT16 C1:LSC-REFL165_I_OUT16 C1:LSC-REFL165_Q_OUT16
C1:LSC-REFL11_I_OUT16     -12.04
C1:LSC-REFL11_Q_OUT16     -14.34
C1:LSC-REFL33_I_OUT16       0.43
C1:LSC-REFL33_Q_OUT16      -0.28
C1:LSC-REFL55_I_OUT16       2.84
C1:LSC-REFL55_Q_OUT16       5.64
C1:LSC-REFL165_I_OUT16      4.40
C1:LSC-REFL165_Q_OUT16      0.10

So these offsets are small in counts. In meters this corresponds to....less than 3 pm for any of the I signals.

Refl11I = 2.06e-12 meters

Refl11Q = 2.94e-10 meters

Refl33I = 5.28e-13 meters

Refl33Q = 1.07e-11 meters

Refl55I = 2.71e-12 meters

Refl55Q = 3.55e-11 meters

Refl165I = 3.07e-13 meters

Refl165Q = 8.63e-14 meters

 

 

3) Next we want to put large offsets into the error points of the loops

4) Change modulation depth

5) Check IMC length (todo for Q/Manasa for Tuesday - Wednesday)

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