National Nuclear Security Administration

Researchers develop a new mathematical tool for analyzing and evaluating nuclear material

January 8, 2016

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Lawrence Livermore National Laboratory scientist Les Nakae, front, shows off a liquid scintillator detector for measuring neutrons and gamma rays with nanosecond timing, which requires the new theoretical formulations detailed in a recent research paper. Joining him are team members, from left: Neal Snyderman, Jerome Verbeke and Ken Kim. Not shown is Manoj Prasad. Photo by Julie Russell/LLNL

Lawrence Livermore National Laboratory scientists have created a new method for detecting and analyzing fission chains to assess and evaluate nuclear material.

The powerful mathematical tools enable the team to detect, analyze and assess unknown objects containing fissionable material in a wide range of applications, from safeguards and border security, to arms control and counterterrorism. The research appears in a recent edition of the journalNuclear Science and Engineering.

Special nuclear materials (SNM) -- highly enriched uranium (HEU) and plutonium 239 -- are unique among radioactive materials in sustaining neutron-induced fission chain reactions. Only SNM naturally create self-perpetuating fission chain reactions and in turn emit bursts of many neutrons and gamma rays.

Their new methods are designed to exploit the burst timing pattern of neutrons and gamma rays emitted by fission chains in HEU and plutonium. One of the goals is to determine the mass and geometric properties of the unknown material and its configurations.

Learn more about their method.