New Models for Prompt Neutron Emissions from Nuclear Fission

Year
2013
Author(s)
S. A. Pozzi - Department of Nuclear Engineering & Radiological Sciences
E. W. Larsen - Department of Nuclear Engineering and Radiological Sciences
R.C. Haight - Los Alamos National Laboratory
A Enqvist - Department of Nuclear Engineering and Radiological Sciences, University of Michigan
Marek Flaska - Department of Nuclear Engineering & Radiological Sciences, University of Michigan
Enrico Padovani - Dipartimento di Energia, Politecnico di Milano
S. D. Clarke - Department of Nuclear Engineering & Radiological Sciences, University of Michigan
Brian M. Wieger - University of Michigan
N. Puppato - University of Michigan
M. J. Marcath - University of Michigan
Abstract
This paper describes the development of new models for neutron emissions for the simulation of spontaneous and induced fission events. The models include the number, energy, and angular distributions of prompt neutrons from fission. In this work, the models are enhanced to separately describe the angular distributions of pre-scission neutrons, which are emitted isotropically and neutrons that are emitted from fully-accelerated fission fragments, and thus are anisotropic with respect to the fission fragment direction. The paper discusses these models and compares them to experimental data acquired with our measurement systems for both Cf-252 spontaneous fission and U-235 neutron-induced fission. A discussion of correlated neutron detections and fission chain analysis in bulk fissile material such as highly enriched uranium in metal form is also included.