Integral experiments at the National Ignition Facility for Nuclear Data Validation on Modeled Neutron Flux Spectra*

The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) is a unique source of neutrons that uses laser inertial confinement to drive the deuterium-tritium fusion reaction. The reaction produces a very high flux output and a monoenergetic 14.06 MeV neutron source peak. With such a strong source, various possibilities are opening up for a list of applications by tailoring the neutron spectra. The presented research focuses on using neutrons with various energies for neutron activation studies and cross section measurements. The idea is to build optimized energy tuning assemblies to "isolate" and emphasize specific energy channels for the validation of known data weaknesses at energies below 14 MeV. UC Berkeley’s newly developed metaheuristic optimization software is used to design ETAs for a series of integral benchmarking experiments. The latter allows to investigate the impact of the nuclear data on materials of interest for NIF’s stewardship.