Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Department of Engineering Physics

First Advisor

James E. Bevins, PhD


An energy tuning assembly was developed to spectrally shape the National Ignition Facility deuterium-tritium fusion neutron source to a notional thermonuclear and prompt fission neutron spectrum to fulfill neutron source capability gaps. The experimental neutron environment was characterized with activation dosimetry, neutronics and covariance models, and unfolded to determine the as-fielded neutron spectrum. The first energy tuning assembly was demonstrated to create synthetic spectrally accurate post-detonation fission products, enhancing U.S. technical nuclear forensics capabilities. ATHENA, a second-generation energy tuning assembly, was also optimized to meet similar objectives, but the new platform neutron fluence efficiency was increased by a factor of 2.7. The ATHENA platform was experimentally fielded to benchmark and validate the models, with an unfolded reduced chi-square metric of 1.4, preparing for future active measurement of electronic devices. The novel ATHENA platform provides a capability to perform integral nuclear data measurements and active experimentation on electronics components in a unique radiation environment.

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DTIC Accession Number