Scaling of laboratory neutron sources based on laser wakefield-accelerated electrons using Monte Carlo simulations

Neutron sources based on laser-accelerated particles have attracted interest as they may provide a compact, cost-effective alternative to conventional sources. Recently, laser-driven neutron sources, based on ion acceleration, demonstrated neutron resonance spectroscopy, imaging and resonance imaging in first proof-of-principle experiments. To drive these sources efficiently with laser-accelerated ions, high laser pulse energies, in the range of tens to hundreds of Joules, with sub-ps pulse duration are needed. This requirement currently limits ion-based laser neutron sources to large-scale laser systems, which typically have maximum repetition rates in the order of a few shots per hour. In this paper, we investigate a potential path to circumvent these limitations by utilizing high repetition rate capable laser wakefield acceleration of electrons to drive a neutron source with high conversion efficiency. Monte Carlo simulations are performed to calculate neutron yields for various electron energies and converter materials, to determine optimal working parameters for an electron-based laser-driven neutron source. The results suggest that conversion efficiencies exceeding 25% can be achieved, depending on the electron energy and converter material. This electron-based approach could provide a neutron source with up to 10¹¹n/s with state-of-the-art laser sources (ELaser ≲ 1J, τLaser ≲ 50fs, ∼ 1kHz).