High-brightness near-GeV energy electron beams from a laser wakefield accelerator for long-standoff nuclear interrogation*

High-brightness monochromatic electron beams are generated in a wakefield accelerator driven by a 100 TW laser. The energy can be varied from 20-800 MeV by varying laser and plasma parameters. Stable electron beams are obtained using self-injection and optical injection. The ability of these beams to penetrate large thicknesses of dense material and an angular spread of $<$5 mrad makes them suitable as active interrogation probes for long standoff nuclear activation of concealed nuclear materials. A series of ($\gamma $,xn) activation measurements were performed to demonstrate the viability of this technique. MCNP and GEANT Monte Carlo simulations are used to aid experiment design and interpretation.