Stand-off detection with an active interrogation photon beam

Active interrogation measurements with a bremsstrahlung photon beam were taken using a hybrid coded imaging and spectroscopic identification system developed at the Naval Research Laboratory (NRL). Measurements were taken using a bremsstrahlung photon beam produced by the Photonuclear Inspection and Threat Assessment System (PITAS) bremsstrahlung photon source at the Idaho Accelerator Center's (IAC) Pocatello Airport facility. The 3 to 7 MeV delayed gamma-ray signature for depleted uranium (DU) was observed and was not seen with a lead target. The delayed gamma-rays were localized to the position of the DU using the coded imager.