BEAM DYNAMICS FOR EXTREME ELECTRON BEAMS

The extreme electron beams are characterized by parameters that are comparable or superior to the state of the art. The beams parameters proposed in the more advanced machines under development or in operation demonstrate that extreme beam qualities are necessary to conceive experiments meeting the demands of cutting-edge research. The optimization of parameters such as brightness, beam current or energy spread plays a major role in the design choices of new and competitive machines. A large amount of simulations of beam dynamics is required, accompanied later by a specific R&D of machine components and demonstration experiments. In the field of beam dynamics, the development and improvement of tracking simulators and optimization tools is a main topic. For this reason, in the beam physics group of INFN & University of Milan the code GIOTTO, based on a genetic algorithm, is being developed for years specifically for this purpose. During the work of PhD, I developed new features in the GIOTTO code that allowed me to apply it to new type of problems: simulation of a beam based method for the increase of the brightness of linac beams, design from scratch of matching lines for plasma driven FELs (Free Electron Lasers), the study of new linear acceleration and compression techniques and a preliminary study on how to produce an ultra-cold beam for a quantum-FEL. All these works are united by being applied to linear machines dedicated to the production of high-brightness electron beams for various purposes. During the last year of PhD, I had the opportunity to participate in the design of an FEL source, named MariX. MariX is based on a compact acceleration scheme where the electron beam propagates twice through a superconducting standing wave linac thanks to an arc compressor that reverses the direction of the beam and compresses it.