need help for centroid tracking problem

[shancai]

Hi Michael,

When I simulate transport line with achromat, I think the centroid should be zero. But the tracking result is not zero.
I don't know what's wrong with my setting. Can you give me some help?

Regards,
Shancai
NSRL

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septum.ele

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[michael_borland]

Shancai,

The problem is that the edge model you've chosen includes the effect of extended fringe fields on the trajectory, so the trajectory is not symmetric inside the dipoles. Hence, it can't return to zero. You can fix this by allowing elegant to adjust the strength of the fields to restore the trajectory, by setting FSE_CORRECTION=1.

--Michael

[shancai]

Thanks a lot！