Ultra-short, high-energy (up to few GeVs) electron beams can be accelerated over just a few centimeters by making an ultra-intense laser interact with a gas-jet, with a technique called “Laser Wakefield Acceleration” (LWFA). Thanks to their small size and the ultra-short duration of the accelerated electron beams, these devices are potentially interesting for a variety of scientific and technological applications. However, LWFA accelerators do not usually provide enough charge for most of the envisaged applications, in particular if a high beam quality and a high electron energy are also required. The goal of this thesis is to implement a novel LWFA injector concept in several state-of-the-art laser facilities, in France and abroad. This injector concept, recently conceived in our group, consists in a solid target coupled with a gas-jet, and should be able to accelerate a substantially higher amount of charge with respect to conventional strategies, while preserving at the same time the quality of the beam. The proposed activity is mainly experimental, but with the possibility to be involved in the large-scale numerical simulation activities that are needed to design an experiment and to interpret its results. The PhD student will have the opportunity to be part of a dynamic team with strong national and international collaborations. They will also acquire the necessary skills to participate in laser-plasma interaction experiments in international facilities. Finally, they’ll have the possibility to be involved in the numerical activities of the group, carried out on the most powerful supercomputers in the world with a state-of-the-art Particle-In-Cell code (WarpX, Gordon Bell prize in 2022).