Magnetic field mapping simulations of sub-mm period undulators for the next generation X-ray free electron lasers

Abstract

There is a growing interest on the compact XFELs to be used in applications such as medical science (surgery, fat removal), material science and military. In order to build a compact XFEL, constructing an undulator with sub-millimeter period (λ<inf>u</inf>) is mandatory. Many problems arise due to miniaturization of undulators, such as keeping the magnetic field high while still having a considerable gap to minimize beam scraping. In this work, RADIA program has been employed for the modeling of sub millimeter period undulators (20μm<λ<inf>u</inf><400μm) with three different magnet configuration, namely Up–Down​ (↑↓↑↓…), Halbach (Wiggler) (↑→↓←↑…) and Hybrid (→↑←↓→…). Effects of sub-millimeter undulator period and gap on the magnetic field pattern of the undulator have been discussed. © 2020 Elsevier B.V., All rights reserved.