Tailoring laser wakefield accelerated electron beams. An experimental study on the influence of experimental conditions on electron beam parameters

Laser wakefield acceleration (LWFA) has emerged as a promising concept for the next generation of high energy electron accelerators. In LFWA a high intensity ultrashort laser pulse drives plasma density waves, inducing a high accelerating field gradient in the order of GV/m. To create stable reproducible electron beams, tailoring of experimental parameters like gas density, laser energy and laser pulse duration is required. In this talk we present an overview of our experimental studies with the DRACO (3 J on target, 30 fs) laser on ultrasonic gas-jet targets (He and He-N₂ mixtures). We discuss the influence of experimental parameters on beam parameters like beam charge, shot-to-shot stability and energy distribution, both in the self-injecting bubble regime as well as in the ionisation injection regime.