Fission products are neutron rich and typically undergo b–-decay. In a few cases, the daughter is produced in an excited nuclear state and itself emits a neutron. These b-delayed neutrons provide a highly selective and quantitative means to interrogate fissile material. Several groups have proposed numerical methods to try to ascertain the composition of an unknown that may contain, e.g. 239Pu and/or 235U by exploiting the small differences in the populations of the delayed neutron precursors and analyzing the tally of delayed neutrons versus the time after irradiation. We have taken a slightly different approach, optimizing the figure of merit for the technique by maximizing detectable neutrons per unit experiment time, and altering the irradiation conditions to achieve discrimination. We will show that even with relatively low-flux irradiation conditions it is possible to get quantitative information on samples containing less than 100 ng of fissile material.

Delayed neutron spectroscopy for characterization of special nuclear material

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.