Author: Chung, T.Y.
Paper Title Page
WEP100 Conceptual Design of a Permanent Magnet Undulator for Fast Pulse-to-Pulse Polarization Switching in an FEL 545
  • T.Y. Chung, C.-S. Hwang
    NSRRC, Hsinchu, Taiwan
  In this paper, we propose the design of an undulator to alter polarization at a fast frequency and the energy spectrum pulse-to-pulse in free-electron lasers (FELs). A fast time varying magnetic field generated in an undulator can alter characteristic light features. An electromagnetic (EM) and permanent magnet (PM) type undulator provides typically a magnetic field switching frequency below 100 Hz. Inductance and heating issues from coils limit the performance for the EM type and favor small magnetic fields and longer periods and for the PM type, strong magnetic forces between magnet arrays create undesired relative motion. In this paper, we discuss these issues and propose an undulator made of Halbach cylinders with rotating magnet arrays to switch the magnetic fields. Concept, magnet structure and performance are discussed in this note.  
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About • paper received ※ 30 July 2019       paper accepted ※ 26 August 2019       issue date ※ 05 November 2019  
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