Spectral investigations of Laser-wakefield accelerator dynamics and advanced brilliant light sources

In order to improve quality and reproducibility of electron beams by Laser-wakefields acceleration (LWFA) for brilliant X-ray sources, at the HZDR we investigate the radiation emitted by LWFA and the resulting electron beams both in theory and experiment.

Experimentally, we are currently setting up an ultra-broadband, staggered spectrometer system ranging from the UV (200 nm) to the mid-IR (12µm) for analyzing coherent transition radiation from electron bunches to infer bunch durations and temporal structures down to sub-fs resolution at single-shot.

Aiming for a quantitative understanding of spectral signatures emitted by LWFA in arbitrary directions, we have added a Liénard-Wiechert type radiation module to the PIConGPU code for calculating online, spectral "sky-maps", as well as logarithmic spectra from IR to X-ray energies, using all particles of a 3D-PIC simulation.

Towards an optical FEL, either by conventional or LWFA electrons, we discuss design goals and feasibility of Travelling-wave Thomson scattering geometries.