Measurements of Photofission Neutron and Photoneutron Production from ²³⁵U, ²³⁸U, and ²³⁹Pu Below 10 MeV

A long-standing nuclear security challenge is the need to screen cargo for special nuclear materials in a way that is safe and scalable. The neutrons emitted by the fission process itself constitute a unique signature of these materials, so there is significant interest in initiating fission with gamma rays at energies low enough to be produced by a compact accelerator. We report results from measurements of neutrons produced through photofission and photoneutron production by nearly monoenergetic photons below 10 MeV incident on ²³⁵U, ²³⁸U, and ²³⁹Pu. An overview of methods, supporting measurements, and comparisons with literature values will be presented.