Neutron Imaging and Spectroscopy of Plutonium Using a Handheld Dual Particle Imager

A prototype handheld dual particle imager composed of stilbene bars coupled to silicon photomultipliers was used to measure a 4.5 kg sphere of alpha-phase weapons-grade plutonium and a canister containing 3.4 kg of plutonium oxide (7%
²⁴⁰
P u and 93%
²³⁹
P u). Each object was measured independently and both objects were measured in the same field of view separated by 50 cm. Experimental results of the measurements conducted are presented. These results demonstrate the ability of the handheld dual particle imager to image and obtain neutron spectroscopic information for sources that would be of great interest for nuclear safeguards and emergency response applications.