Laser plasma accelerators produce today ultra short, quasi-monoenergetic and collimated electron beams with potential applications in material science, chemistry and medicine. The laser plasma accelerator used to produce such an electron beam is presented. The design of a laser based accelerator designed to produce more energetic electron beams with a narrow relative energy spread is also proposed here. This compact approach should permit a miniaturization and cost reduction of future accelerators and associated X-Free Electrons Lasers (XFEL).