Comparison Of Neutron Coincidence And Multiplicity Counting Techniques For Safeguards

Neutron counters have been used by safeguard inspectors worldwide for over 20 years to accurately perform Non-Destructive Assays of pure samples of plutonium and uranium. These systems rely on the neutron coincidence counting technique to separate time-correlated fission neutrons from random, uncorrelated neutrons to determine the fissile mass. Impure samples such as mixed-oxide (MOX) scrap materials and salts present a unique problem because they cannot be accurately measured using the standard coincidence technique. Instead, they require an enhanced technique, multiplicity counting, to accurately quantity the fissile content. Test data will be presented in this paper to compare multiplicity and coincidence counting, and to identify sample types that can be assayed using these techniques.