High-yield and high-angular-flux neutron generation from deuterons accelerated by laser-driven collisionless shock

Abstract

A bright collimated neutron source is an essential tool for global security missions and fundamental scientific research. In this paper, we study a compact high-yield and high-angular-flux neutron source utilizing the break-up reaction of laser-driven deuterons in a $^9\text{Be}$ converter. The neutron generation scaling from such a reaction is used to guide the choice and optimization of the acceleration process for the bulk ions in a low density $\text{CD}_2$ foam. In particular, the collisionless shock acceleration mechanism is exploited with proper choice in the laser and target parameter space to accelerate these ions towards energies above the temperature of the distribution. Particle-In-Cell and Monte Carlo simulations are coupled to investigate this concept and possible adverse effects, as well as the contribution from the surface ions accelerated and the optimal converter design. The simulation results indicated that our design can be a practical approach to increase both the neutron yield and forward flux of laser-driven neutron sources, reaching peak angular neutron flux $>10^{11}$ neutron/sr and yield $>10^{11}$ neutron/pulse with present-day kJ-class high-power lasers. Such developments will advance fundamental neutron science, high precision radiography and other global security applications with the laser-driven sources.