Felix, Design And Instrumentation

In a Free-Electron Laser, FEL, an intense, high quality, relativistic electron beam is forced into a wiggling motion in a periodic array of alternating magnets, the undulator, where it produces the radiation. The generation of the electron beam is non-trivial and quite expensive. FELs have therefore been constructed at various sites in the world as the core of user facilities. FELIX (Free Electron Laser for Infrared eXperiments) is such a user facility, built at the FOM- Institute for Plasma Physics, Rijnhuizen, where intense infrared light is generated over a large spectral range with two FELs. The FELIX FELs are fed by an electron beam produced by a traveling wave RF accelerator system, the design of which is the main subject of this thesis. The quality of an FEL is determined to a very large extent by the quality of the electron beam. The requirements for all of the following parameters are high: peak current, energy spread, emittance and stability of the micropulse repetition frequency. These aspects are dealt with in the various chapters of the thesis. For the general understanding of the accelerator aspects and the FEL functioning the 'General Particle Tracker'-code was developed. This code is also used to visualize FEL principles and to derive the relation between the electron beam parameters and the FEL output. The electron beam for FELIX is generated in 'bunches'. The energy can be set between 15 MeV and 45 MeV for coarse tuning of the FELs while fine tuning is done by varying the strength of the undulator