LBNL: Correlated Data in Fission Events

LBNL PIs: Jorgen Randrup (FREYA) and Aaron Hurst (neutron capture data)

This project pulls together several previously independent efforts that collectively are looking at developing deeper understandings of the fission process and neutron capture. In the course of this effort, better fission process models will be incorporated into broadly available modeling tools, better neutron capture data will be made available through the standard libraries, and analysis tools for extracting images and material composition and form will be developed and improved. While addressing different parts of the problem, all of these elements have the common goal of filling in gaps in modeling and analysis capabilities crucial to national needs in arms control, nuclear safeguards, and homeland security.

LBNL works directly with LLNL on two tasks for this project: FREYA and neutron capture data. The complete fission event Monte Carlo, FREYA, is being developed
under this venture.  FREYA simulates complete fission events, thus following the fission fragments as well as prompt neutron and photon emission, conserving energy and momentum (spatial and angular) at each step.  As such, it retains all kinematic information and can thus construct any desired observable.  It is thus possible to study correlations in energy and angle between two neutrons, neutrons and fragments, neutrons and photons, and between two photons.  FREYA is available in the R&D version of MCNP6.  A goal of the current project is for FREYA to become part of the production version of MCNP6, in addition to ongoing development of
the model to make FREYA a tool for both detector development and
analysis of data on correlated signatures.