SIMULATION OF NEUTRON INSPECTION TECHNIQUES BASED ON LASER-PLASMA NEUTRON BEAM AND FIRST EXPERIMENTS WITH CF SOURCE

This thesis is devoted to laser-plasma acceleration technology with an aim to produce the neutron source to foresee the use of neutron beams for addressing volumetric inspection of cargo container in order to provide the feasibility for custom border inspection on seaports and airports. We tried to significantly improve the system for simultaneous detection of hazardous and illicit materials. Neutron beams interact with the samples under study, inducing the emission of characteristic gamma radiation. The analysis of the emitted radiation allows retrieving the composition of a large variety of materials, avoiding visible damage or changes in the chemical composition. Many of these techniques have relied on massive and expensive radiation sources (e.g. particle accelerators) for several decades. In the last years, the advent of a new generation of ultra-short and super-intense lasers of higher intensities of 10 19 W/cm 2 paved the way for the exploration of new laser plasma interaction scenarios. Among the others, laser-driven particle acceleration, consisting in the production of high-energy electrons and ions. When a laser pulse is focused on a solid target, is attracting increasing attention in the scientific community. Indeed, the compact size and multi-particle nature of laser-based accelerators make them attractive for applications in several fields, from astrophysics to medical science. However, the applicability of laser-driven radiation sources to the elemental analysis of materials remains substantially unexplored. Therefore, the goal of this thesis work is to address the possibility of neutron productions by exploiting laser-driven particle acceleration mechanism for materials characterization, using neutron-in and gamma-out reactions. To this aim, we provide the brief detail for neutrons production in laser plasma acceleration using fusion and portable laser driven acceleration in target normal sheath acceleration (TNSA) mechanism using d(d,n)He, 7Li(p,n)4Be, 3Li(d,n)4Be reactions. Neutrons produced from these nuclear reactions are used in order to characterize the target object for materials identification. Geant4 simulation was made in an experimental approach. First, to make laser-driven neutron sources suitable for the mentioned applications. Then neutrons produced were used to characterize the numerous illicit and explosives materials that can be mixed and diluted to create countless varieties, the majority of which are made up entirely of the components H, C, N, and O. Lastly, the simulation was performed with an radioactive neutron source and results were obtained to test on basis of a proof-of-principle experiment in laboratory. The outcomes of this study confirms that materials characterization can be performed with the neutron produced from laser facilities. The predictions made from 252 Cf neutron source shows that 252 Cf source emits high-energy correlated neutrons and gammas, making it a valuable interrogation source. Major problem of this source is, it cannot be turned off, and emits radiation continually. This limits their use to small experiments that depends on constant neutron flux without pulsed emission. Therefore, it may be advantageous to switch on and off the interrogating source, laser driven fusion neutron sources are practically suitable since they lack intrinsic gamma-neutron correlations.