Laser Driven Electron Acceleration from Near-Critical Density Targets towards the Generation of High Energy γ-Photons

In this paper, we investigate the production of high energy gamma photons at the interaction between an ultra-high intensity laser pulse with an energetic electron beam and with a near-critical density plasma for the laser intensity varying between 1019–1023 W/cm2. In the case of the interaction with an electron beam, and for the highest laser intensities considered, the electrons lose almost all their energy to emit gamma photons. In the interaction with a near-critical density plasma, the electrons are first accelerated by the laser pulse up to GeV energies and further emit high energy radiation. A maximum laser-to-photons conversion coefficient of 30% is obtained. These results can be used for the preparation of experiments at the Apollon and ELI laser facilities for the investigation of the emission of high energy γ-photons and to study the electron-positron pair creation in the laboratory.