Laser-driven undulator sources require high-charge, monochromatic relativistic electron beams. Hence, a key challenge here is the further optimisation of laser-wakefield acceleration (LWFA) in collaboration with Projects A.3.4 and A.2.6. Externally, we will continue the collaboration with the groups of S. Hooker from Oxford University and W. Leemans of Berkeley Lab in this field. We will particularly focus on electron injection and beam evolution by developing gas targets with shaped plasma profiles. The optimised LWFA beam will drive two radiation source projects: LUX (Laser-Undulator X-ray Source) generates spontaneous undulator radiation from an LWFA electron beam (see Fig. A.3.3).
LUX will be operated with electron beams of 1-2 GeV energy driven by ATLAS-3000 and will be used for ultrafast time-resolved radiation biology in B.2c and B.2d. On the diagnostic side, many detailed parameters of the electron bunches have remained unknown so far, e.g. the detailed energy chirp, bunch profile and emittance characteristics. A new beam characterisation method based on the Optical Replica Synthesiser13, as it is called, will be developed in collaboration with the group of K. Hacker from DESY. Together with a synchronised probe pulse, this source will be ready for experiments following the research in research areas B and C.
Advancing LUX to FEL-operation and thereby realising a Laboratory-scale X-ray Laser (LXL) is far more ambitious and calls for greatly improved electron beam quality. State-of-the-art sub-GeV laseraccelerated electron beams are approaching the parameter regime where – according to numerical simulations – FEL operation in the XUV range may become feasible. Successful demonstration would constitute a major milestone towards a multi-keV laser-driven FEL. The feasibility of which will depend on our ability to permanently improve the electron beam quality whilst increasing its energy.