• H. Guo
  PSI-LRF, Villigen, PSI
• A. Adelmann, A. Falone, C. Kraus, B.S.C. Oswald
  PSI, Villigen
• P. Arbenz
  ETH, Zurich

The X-ray Free Elec­tron Laser (Swiss­FEL) under de­vel­op­ment at the Paul Scher­rer In­sti­tut (PSI) will em­ploy a spe­cial type of a de­flect­ing cav­i­ty, LOLA*, for beam di­ag­nos­tics. Since this cav­i­ty's de­sign breaks the sym­me­try, a com­plete 3-di­men­sion­al eigen­modal anal­y­sis is in­dis­pens­able. The 3-di­men­sion­al eigen­modal solver fe­maxx em­ploys the fi­nite el­e­ment method and has been de­vel­oped in a col­lab­o­ra­tion be­tween PSI and the Swiss Fed­er­al In­sti­tute of Tech­nol­o­gy Zurich (ETH). The fe­maxx code uses the graph­i­cal fron­tend pro­gram hero­nion for the ap­pli­ca­tion of bound­ary con­di­tions, in­clud­ing sym­me­try, and gen­er­ates a tetra­he­dral mesh. We use fe­maxx to an­a­lyze the ex­ist­ing LOLA cav­i­ty de­sign**, com­pute elec­tro­mag­net­ic eigen­modes with their cor­re­spond­ing eigen­fre­quen­cies, and as­so­ci­at­ed per­for­mance fig­ures. Since these are large com­pu­ta­tion­al prob­lems fe­maxx has been op­ti­mized for dis­tribut­ed mem­o­ry par­al­lel com­pute clus­ters. For the fur­ther usage in the beam dy­nam­ics code OPAL we sam­ple the eigen­modal fields on a 3-di­men­sion­al Carte­sian grid.

* A. Falone, et al: RF deflector for bunch length measurement at low energy at PSI. Proceedings of PAC2009.
** P. Arbenz et al., Parallel Computing, 32: 157-165 (2006).