Numerical investigation of spallation neutrons generated from petawatt-scale laser-driven proton beams

TL;DR

This paper numerically investigates the potential of petawatt-scale laser-driven proton beams to generate high-flux neutrons via spallation, highlighting their promise as a cost-effective alternative to traditional neutron sources.

Contribution

It introduces a numerical model combining particle-in-cell and Monte Carlo simulations to predict neutron yields from laser-accelerated protons at petawatt laser facilities.

Findings

Neutron fluxes exceeding 10^23 n/cm^2/s are predicted.

Next-generation laser parameters can enable efficient neutron production.

Potential applications include fundamental research and practical neutron sources.

Abstract

Due to their high cost of acquisition and operation, there are still a limited number of high-yield, high-flux neutron source facilities worldwide. In this context, laser-driven neutron sources offer a promising, cheaper alternative to those based on large-scale accelerators, with, in addition, the potential of generating compact neutron beams of high brightness and ultra-short duration. In particular, the predicted capability of next-generation petawatt (PW)-class lasers to accelerate protons beyond the 100 MeV range should unlock efficient neutron generation through spallation reactions. In this paper, this scenario is investigated numerically through particle-in-cell and Monte Carlo simulations, modeling, respectively, the laser acceleration of protons from thin-foil targets and their subsequent conversion into neutrons in secondary heavy-ion targets. Laser parameters relevant to the 1 PW LMJ-PETAL and 1-10 PW Apollon systems are considered. Under such conditions, neutron fluxes exceeding $10^{23}\,\rm n\,cm^{-2}\,s^{-1}$ are predicted, opening up attractive fundamental and applicative prospects.