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Description
Efficient gamma and neutron production from laser-accelerated electrons is crucial for advancing applications in science and technology. It relies on generating γ−photons via Bremsstrahlung and subsequent photo-nuclear reaction within the high-Z converter. This work considers the evolution of the electron bunch studied by Particle-in-Cell (PIC) simulations of Laser Wakefield Acceleration and subsequently optimises converter configurations for maximizing gamma and neutron yields using Monte Carlo simulations. A high-resolution PIC simulation, inspired by the work of V. Horný et al. (Phys. Rev. E 110, 035202), was performed using Smilei to model a 6-fs interaction of a 1.5-J laser pulse. The simulation captured the acceleration of several nanocoulombs of electron bunches, achieving energies of up to 300 MeV in the primary Laser Wakefield Acceleration (LWFA) regime and up to 600 MeV in the secondary Plasma Wakefield Acceleration (PWFA) regime. Electron energy spectra from different phases of the PIC simulation were extracted and used as inputs for FLUKA simulations, where lead converter thickness was varied to optimize gamma and neutron production separately. Complementing this, idealized electron beam simulations in FLUKA explored neutron and photon responses for fixed beam energies and varying target lengths, providing additional insights. This study highlights the interplay between electron beam properties, target geometry and particle yields, offering practical strategies for optimizing secondary particle sources in laser-plasma experiments.
