Electron Accelerators with Lasers From mJ to kJ at ELI-Beamlines

The extremely high electric fields sustainable by plasma make the Laser Wakefield Acceleration (LWFA) the most compact technique to generate very highly relativistic electron beams in the MeV-to-GeV regime. At ELI-Beamlines, we have unique high repetition rates and high-peak power laser systems (from mJ to kJ per pulse) that are the engines for our ultra-relativistic electron beamlines, routinely offered to worldwide users.

In this talk, I will present the schemes of the LWFA used to produce multi-tens of MeV electron beams at 1 kHz driven by the L1-Allegra TW-class laser (40 mJ, 14 fs) [1] and multi-GeV electron beams at Hz repetition rate driven by the L3-HAPLS PW-class laser (13 J, 30 fs) [2, 3].

In the first case, we can offer stable ultra-relativistic electron beams as a unique source for basic research, biomedical applications, and radiotherapy, as well as high flux sources to produce secondary radiation, such as X-rays or positrons. I will briefly show the first on-demand in-air irradiations performed at ELI-Beamlines with high dose rate electrons on biological targets. In the second case, high-power laser pulses have been shown to be self-waveguided in a plasma channel, thanks to a novel all-reflection optical setup, to achieve acceleration of electron beams to energies up to 5 GeV with improved pointing stability.

To determine the optimal laser and plasma parameters for a given experimental setup, the optimization of electron acceleration was carried out using particle-in-cell simulations [4]. Based on the simulation results, the corresponding optimized scaling laws for electron energy and acceleration distance were obtained.