bpm_noise and response matrix

[Max]

Dear Michael and collaborators,

I am simulating a measurement of the response matrix with bpm noise.

I use the following instructions:

&correct
mode = trajectory
bpm_noise[0] = 0.00001,0.00001,
trajectory_output = "%s.traj"
corrector_tweek[0]=0.00003,0.00003
&end

&correction_matrix_output
output_at_each_step = 1,
response[0] = dataht.sdds,datavt.sdds
&end

for the purpose of estimating the effect of the bpm noise on the fit of the response matrices.
I find that the reponse matrices dataht.sdds,datavt.sdds, and the accuracy of the subsequent fit, are quite insensitive to the amplitude of the bpm_noise, even for a bpm_noise as large as 1 cm ! I am assuming that the units of bpm_noise are in m.

I thought that maybe, if the noise level is the same in the two trajectories computed to derive the response matrix, it has little effect, since the offsets subtract (not unlike a bpm displacement) ?

I thank you in advance for your help,

Max

[michael_borland]

Max,

The response matrix computation from elegant does not make use of the bpm noise level. It is used only in the correction stage.

If you want to determine the effect of BPM noise, I think the best way is to just determine it analytically.

--Michael