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Linear quadruple fringe fields

2015-10-27
2015-12-14
  • Simone Liuzzo

    Simone Liuzzo - 2015-10-27

    What about quadrupole linear fringe fields?

    translating a SAD lattice to AT I noticed that AT is missing the linear quadrupole fringe fields.

    Is anybody working on this topic?

    ciao
    Simone

     
  • Nicola Carmignani

    Hello,
    I added the elegant-like fringe fields in QuadMPoleFringePass.c, using part of the elegant code, but the passmethod is not committed in the repository.
    Nicola

     
  • Simone Liuzzo

    Simone Liuzzo - 2015-10-29

    WOW!
    I compared with the SAD (not MAD, thanks to M.Biagini, LNF-INFN) code traking trough a single quadrupole, and the beta and alpha are identical!
    To perform conversion of the field F1 in SAD, we have to set :
    QD.fringeIntP0=[0 F^2/48 0 0 0]
    QD.ringeIntM0=[0 F^2/48 0 0 0]

    here the comparison for a defocussing quadrupole for a line composed by [marker, Drift, QD, Marker] with intial conditions beta=(25,25), alpha=(0,0):

    AT without linear fringe
    beta (h,v): 22.985948475 27.165470439
    alpha (h,v): 4.246241518 -4.802585286

    AT with linear Fringe
    beta (h,v): 22.985968493 27.165448947
    alpha (h,v): 4.242611173 -4.806613781

    SAD
    beta (h,v): 22.9859 27.1654
    alpha (h,v): 4.24261 -4.8066

    I Hope this will be committed soon in the repository! post when you do!

    ciao
    simone

     
  • Xiaobiao Huang

    Xiaobiao Huang - 2015-12-14

    Hi Nicola and Simone,

    Quadrupole linear (and nonlinear) fringe field was added to AT in 2011. And it has been reported at FLS2012 Workshop.
    https://www.jlab.org/conferences/FLS2012/talks/Mon/Huang_lattice_modelling.pptx

    I recommended the AT quadrupole fringe field implementation to Michael Borland. That's probably why Elegant gives identical results in your test.

    I am attaching the source code and will upload it to the repository.

    Xiaobiao

     

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