Design of a Double Focusing Beam Transport System for the 25 MeV Electron Beam

Abstract

At the University of Twente in collaboration with the Technical University of Eindhoven a Free Electron Laser is being realised with a set-up of two accelerators. The injector is a 6 MeV photo cathode linac producing a high brightness beam. The second accelerator is a Race-Track-Microtron. For the Free Electron Laser project TUEFEL fase II a system was designed to transport the electron beam with an energy of 25 MeV from the racetrack microtron to the undulator. The constructive features of the undulator and resonator demand a detailed matching between electron beam and undulator. The relative small length of the resonator requires a compact injection part of the transport system. Matching of the electron beam is performed in two steps general fixed focusing is done with quadrupoles in a dispersive section. Fine tuned focusing is done in the dispersion free part of the transport line. Dynamic 3-D simulations with space charge were done to obtain the design parameters of the beam transport system. Optimal matching of the electron beam at the undulator’s entrance is obtained