2009.09.21 - Cbar Simulation

NOTE:

These results are not valid-- the RMS values returned are skewed by inaccurate modeling at L3 detectors (49, 50), which throws off all the results. BPMs 49,50 return Cbar11 = 3.e0, for example. These inaccuracies were not observed on 9/18/09 because resolution and gain/tilt error routines were not present at that time, meaning nonlin_bpm was not being employed. Now that we are using nonlin_bpm, we see the problem. See results from 9/22/09 for results of these jobs after they were re-run. --JSh, 2009.09.22

Results of 9/18/09 simulation of cbar measurements with gain errors and resolution, averaging over 100 seeds for each set of parameters: (note: no actual coupling present in lattice)

Repeat the exercise, this time introducing sk_q02w @ +0.01 and looking at ('meas' - model):

I'm not sure if I believe how independent of resolution these results are. Possible causes:

• Resolution causes random errors in position, which may be 'smoothed out' over the 1000 turns of these data sets. Therefore, we could expect to see more contribution to Cbar measurement errors from resolution at a smaller number of turns.
• Note that when no coupling is present (sk_q02w @0), cbar12 shows some split between the different resolutions. Perhaps when we introduce real coupling, the RMS differences between "measured" and "actual" cbars could be dominated by generally 'poor' agreement in the first place. Note that this doesn't explain why only cbar12 shows this splitting, whereas cbar22/11 show no sign of it.

Also note that the scales differ on all plots. I should go back and rescale everything to the same range for each cbar element...