Speaker
Description
X-ray free-electron laser (FEL) facilities rely on high-brightness electron bunches to deliver coherent, laser-like pulses on the femtosecond time scale at short wavelengths. Developments in electron sources and injector technology are pushing the limits on the beam emittance and energy spread, aiming to increase the bunch density in 6D phase space in order to optimise the properties of the FEL radiation produced. The collective interactions of electrons within the bunch, when confined to a small volume, can dilute the electron bunch brightness, particularly along an acceleration and transport line that can reach over a kilometre in length. This contribution presents the strategies envisaged for preserving beam brightness in the context of the conceptual design of the UK XFEL, with a particular focus on novel techniques for mitigating collective interactions during bunch length compression. It is demonstrated that multiple approaches are available that can meet the stringent requirements on the electron bunch to produce high-quality FEL radiation.
