Laser-driven γ-ray, positron, and neutron source from ultra-intense laser-matter interactions

In ultra-intense laser-matter interactions, gamma-rays are effectively generated via the radiation reaction effect. Since a significant fraction of the laser energy is converted into gamma-rays, understanding of the energy transport inside of the target is important. We have developed a Particle-in-Cell code which includes generation of the gamma-rays, their energy transport, and photo-nuclear reactions. Using the code, we have investigated the characteristics of the quantum beams generated by the transport of the laser-driven gamma-rays. It is shown that collimated, mono-energetic positron beams with hundreds of MeV are generated by using thick targets. Neutron beams are also effectively generated by using beryllium targets via photo-nuclear reactions. These lead to the proposal of quantum beam sources of gamma-rays, positrons, and neutrons with distinctive characters, which are selectively generated by choosing target conditions. (C) 2015 AIP Publishing LLC.