Proof-of-principle demonstration of epithermal neutron resonance spectroscopy utilizing a compact laser–driven electron accelerator

Abstract

Epithermal neutron resonance spectroscopy is a key nondestructive approach for discerning material properties. However, the existing spallation and accelerator-based photonuclear neutron sources employed in this spectroscopy are huge and immobile, restricting their application in specialized scenarios. Here, we demonstrate a compact short-pulsed photonuclear neutron source driven by a terawatt femtosecond laser–based electron accelerator. After moderation, this neutron source maintains an outstanding time-resolution of 0.8 μ s at 5 eV, and its energy resolution can be less than 3% at a flight distance 1.72 m. When this compact neutron resonance spectroscopy facility is utilized to examine silver (Ag) and indium (In) metal sheets with a high signal-to-noise ratio, it distinctly reveals the shape of resonance absorption peaks for 115 In at 1.46 eV and 109 Ag at 5.19 eV. This laser-driven electron accelerator offers a solution, overcoming traditional source drawbacks and holding great potential for on-site nuclear material analysis and high-precision nuclear data acquisition.