Study of the Electron Transport in the COXINEL FEL Beamline Using a Laser-Plasma Accelerated Electron Beam

Abstract : The ERC Advanced Grant COXINEL aims at demonstrating free electron laser (FEL) at 200 nm, based on a laser-plasma accelerator (LPA). To achieve the FEL amplification a transport line was designed to manipulate the beam properties. The 10 m long COXINEL line comprises a first triplet of permanent-magnet variable-strength quadrupoles (QUAPEVA), which handles the large divergence of LPA electrons, a magnetic chicane, which reduces the slice energy spread, and finally a set of electromagnetic quadrupoles, which provides a chromatic focusing in a 2-m undulator. Electrons were successfully transported through the line from LPA with ionization-assisted self-injection (broad energy spectra up to~250 MeV, few-milliradian divergence).