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Reports until 13:31, Friday 07 April 2023
H1 CAL (CAL, CSWG, ISC)
jeffrey.kissel@LIGO.ORG - posted 13:31, Friday 07 April 2023 - last comment - 14:38, Friday 07 April 2023(68500)
Retuning OMC DCPD Balance Matrix after Whitening Compensation Fixes
J. Kissel

Using the same methodology and scripts that I used in LHO:68360, I re-measured the coherent transfer function and incoherent amplitude spectral density ratio between the OMC DCPDs with the SQZ system off now that we've fixed the whitening filter compensation LHO:68496. 

The result I get for the coherent ratio (the transfer function), g, and incoherent ASD ratio, h, are
    g=1.03704; 
    h=1.01873;  

Converting these coefficients to a balance matrix, they become
    MM_proposed =
      0.99963       1.0004
      0.98198      -1.0184


Encouragingly, the DCPD SUM elements are now even more balanced.

I've installed the above proposed matrix elements while in nominal low noise by taking advantage of the fact that we have two identical sensors capable of sensing DARM:
    $ caput H1:OMC-DCPD_A0_TRAMP 10.0; caput H1:OMC-DCPD_B0_TRAMP 10.0;
    $ caput H1:OMC-DCPD_A0_GAIN 0.0; caput H1:OMC-DCPD_B0_GAIN 2.0; # wait until this finishes
    $ caput H1:OMC-DCPD_MATRIX_1_1 0.99963; caput H1:OMC-DCPD_MATRIX_2_1 0.98198;
    $ caput H1:OMC-DCPD_A0_GAIN 2.0; caput H1:OMC-DCPD_B0_GAIN 0.0; # wait until this finishes
    $ caput H1:OMC-DCPD_MATRIX_1_2 1.0004; caput H1:OMC-DCPD_MATRIX_2_2 -1.0184;
    $ caput H1:OMC-DCPD_A0_GAIN 1.0; caput H1:OMC-DCPD_B0_GAIN 1.0
    $ caput H1:OMC-DCPD_A0_TRAMP 3.0; caput H1:OMC-DCPD_B0_TRAMP 3.0;

I guess that the practice I got on 2023-03-30 makes things a lot easier!
The new data lives here:
    /ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/O3/H1/Measurements/CALCS_FE/
        2023-04-07_1922UTC_H1_OMC_DCPDAB_BalanceMatrix.xml

from which I exported
    /ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/O3/H1/Measurements/CALCS_FE
        2023-04-07_1922UTC_H1_OMC_DCPDAB_BalanceMatrixData_asd.txt
        2023-04-07_1922UTC_H1_OMC_DCPDAB_BalanceMatrixData_coh.txt
        2023-04-07_1922UTC_H1_OMC_DCPDAB_BalanceMatrixData_csd.txt
        2023-04-07_1922UTC_H1_OMC_DCPDAB_BalanceMatrixData_tf.txt

And I used, updated, and committed the same scripts as described in LHO:68362, calculcate_OMCDCPD_balancematrix_ghterms.m and calculcate_OMCDCPD_balancematrix.m.
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jeffrey.kissel@LIGO.ORG - 14:38, Friday 07 April 2023 (68508)
These matrix elements have been accepted in the SDF in both the safe and OBSERVE files for the h1omc model.
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