I calculated the time varying calibration parameters kappa_tst, kappa_pu, kappa_A, kappa_C and Cavity pole for the lock stretch beginning from September 1st using the new ER8 DARM model. All the data used for this analysis had guardian state vector greater than 600 (NOMINAL LOW NOISE). The plots are attached.

Details:

The equation used in this calculation are obtained from the T1500377 document which describes the time varying parameters in details.

For the displacement produced due to pcal, I used the following script to advance the pcal signal by 21 us (LHO alog 21320) , take out the AA filter and and dewhitened the signal.

/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/S7/Common/MatlabTools/xpcalcorrectionER8.m.

I was not able to get kappa_tst closer to 1, which is the expected value of the all kappa's. However, the variation in Kappa_tst is within 1%  which is a good news. I am not sure where the problem is. I will look into it further. For the rest of the plots I assumed kappa_tst to be 1. This assumption only effects kappa_pu because it is the only factor that depends on kappa_tst.

Plots:

The first plot shows the real part of kappa_tst, kappa_pu and kappa_A. Kappa_pu and kappa_A are close to 1 and the variation of these parameters during this time is less than a 1%. kappa_tst under investigation.

The second plot is the imaginary part of the parameters in plot 1. All these values are expected to be 0 or closer to zero. Again, kappa-pu and kappa_A are indeed very close to zero but kappa_tst is not.

The third plot includes kappa_C (change in optical gain) and cavity pole.  Optical gain within a lock stretch seems to be very stable but it varies by few percent between locks. One particular stretch it varied by almost 20% (not sure why, could be commissioning activities). Also, there is evident of some transient at the beginning and end of the locks. Will try to sort the data by intent bit for future analysis.  The cavity pole shows some trend and variation between lock stretches but nothing crazy.

The script used to analyze this is committed to the svn:

/ligo/svncommon/CalSVN/aligocalibration/trunk/Projects/PhotonCalibrator/drafts_tests/ER8_Data_Analysis/Scripts/plotCalparameterFromSLMData.m