Neutrons are very interesting tools for material sounding due to their capacity to penetrate into heavy materials and the possibility of exploiting specific diffusion resonance. Neutron sources used today are either very compact, but with a relatively low flux, or able of generating high flux, but they have then big sizes (based on particle accelerators) and their pulse duration are rather long (µs), what limits the temporal resolution of the aimed sounding. New perspectives are offered in this domain by lasers of high power. Indeed, it was demonstrated that we could, by the interaction between a laser and a suitably adapted target, generate intense neutron beams with durations lower than one nanosecond. A hard point to be validated concerns the repetition rate of these neutron sources, which should be adapted to the repetition rate (of the order of Hz) of new intense lasers.
The thesis will consist in putting together the optimal laser / target couple available today to make a neutron source. Indeed, two laboratories, world leaders in their domain: the LULI, coordinator of the installation APOLLON, expert in big laser installations and in laser / plasma interaction, and the SBT (Low Temperature Department of CEA/GRENOBLE), inventor of the target "ELISE", cryostat producing ribbons of solid Hydrogen for laser / plasma interaction join together to develop and test a neutron source based on the interaction of the laser beam APOLLON with a solid Hydrogen (or Deuterium) target.
The subject consists in characterizing and in optimizing the ribbon of solid Hydrogen, in devising the measure by neutronic imaging, and in characterizing the laser / plasma interaction to establish at best the laws of neutron generation by laser. The thesis will take place at first at the CEA/GRENOBLE, then at the LULI, with a co-supervision of both laboratories. The realized experiments should allow to determine the characteristics that should have a neutron source adapted to the non-destructive control.