High brightness electron source for coherent radiation production

In this work, the main technological issues to produce an high brightness electron beam for x-ray Free Electron Laser (FEL) application are presented and ana- lyzed. The researches conducted have been done as an R&D activities for the new SPARC photoinjector in Italy. The brightness of an electron bunch means high peak current and low beam's emittance. An UV laser and a photocathode is generally used to produce high density charge in an accelerating structure. To minimize the non-linear space charge forces a temporally square pulse on ps scale is needed. In this thesis we report the experimental results of pulse shaping obtained using an acousto-optic programmable dispersive ¯lter and an high energy Ti:SA laser. Robust photocathodes, such as CVD diamond-based and Mg ¯lms, have been studied. Simulations, characterizations and installation of a magnetic chi- cane compressor is described. The experimental observation of an unprecedented ultra large bandwidth FEL radiation is reported and discussed.