I extended my RAM script from DRMI (3DoF) to the full IFO (5DoF).
Again, it calculates the operation point offsets for each DoF from the opt model with RAM. Then the position offsets are added to the model, and calculates the LSC matrix. RAM level is assumed as 0.1% of the PM modulation level, as usual, and lossless for a simple model.
Original matrix without RAM:
REFL f1 : 1.000000 0.000000 0.000008 -0.000005 0.000003
AS f2 : 0.000001 1.000000 0.000005 -0.003523 -0.000001
POP f1 : -3956.958708 -0.000183 1.000000 0.019064 0.000055
POP f2 : -32.766392 -0.154433 -0.072624 1.000000 0.024289
POP f2 : 922.415913 -0.006625 1.488912 0.042962 1.000000
(MICH and SRCL uses the same sensor, with optimised demodulation phase for each DoF.)
Operation position offsets are:
PRCL -3.9125e-11 m
SRCL 9.1250e-12 m
CARM 5.0000e-15 m
and no position offsets for DARM and MICH (because they are differential sensor and not affected by RAM offsets).
Resulting matrix with RAM + RAM offsets, normalised by the original matrix:
REFL f1 : 0.001663 -0.000000 0.003519 0.000005 -0.000003
AS f2 : 0.000004 0.514424 0.000004 -0.001676 -0.000001
POP f1 : 7.140984 -0.001205 15.051807 0.019254 0.000417
POP f2 : 0.029112 -0.319792 0.042583 1.000460 0.024298
POP f2 : -0.310318 -0.014385 -1.761519 0.043005 0.999819
As you can see in the second matrix, the CARM and DARM rows are completely destroyed by the RAM offsets! The signals are half reduced in the DARM case, so the mixture between DARM and MICH are about 50% degraded.
I also would like to extend this script to use the DC readout, but don't know how to calculate the postion offset for AS_DC because the error signal is not zero-crossing for AS_DC anymore. Do you have any suggestions for me?
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