issue with reference_correction and epitch/eyaw misalignments

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GPenn
Posts: 38
Joined: 28 Aug 2018, 09:46

issue with reference_correction and epitch/eyaw misalignments

Post by GPenn » 27 Aug 2021, 12:23

Hi,

I'm seeing a large discrepancy between tracking with and without REFERENCE_CORRECTION in CSBEND elements, when there is also an epitch or eyaw misalignment. The case with REFERENCE_CORRECTION=0 seems like a closer fit to AT calculations, and the final offset is much smaller which seems more reasonable. For a typical bend magnet with epitch=1e-5, there is about a 1 micron difference in final position of the particle (starting on axis). This is with elegant 2021.2.0.

A minimal set of example files is attached. The same size discrepancy appears if I set eyaw instead of epitch, and it also doesn't matter if I use malign_method = 1 or 2. If there is just an etilt, then the difference in tracking results is much smaller.

Thanks,
Gregg
Attachments
csbend.ele
run file, with and without reference_correction
(583 Bytes) Downloaded 96 times
csbend.lte
lattice file
(746 Bytes) Downloaded 101 times

michael_borland
Posts: 1796
Joined: 19 May 2008, 09:33
Location: Argonne National Laboratory
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Re: issue with reference_correction and epitch/eyaw misalignments

Post by michael_borland » 07 Sep 2021, 01:20

Gregg,

Thanks for reporting the bug. The attached file should fix it.

--Michael
Attachments
csbend.c
(210.89 KiB) Downloaded 102 times

GPenn
Posts: 38
Joined: 28 Aug 2018, 09:46

Re: issue with reference_correction and epitch/eyaw misalignments

Post by GPenn » 07 Sep 2021, 21:58

Thank you, that did the trick!

-Gregg

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