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Author Lawrence, Chris C. ♦ Flaska, Marek ♦ Pozzi, Sara A. ♦ Febbraro, Michael ♦ Becchetti, F. D.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY ♦ CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ ACCELERATORS ♦ CHEMICAL EXPLOSIVES ♦ HYDROGEN ♦ NEUTRON SPECTRA ♦ NEUTRON SPECTROSCOPY ♦ NEUTRONS ♦ NONLINEAR PROBLEMS ♦ PLUTONIUM ♦ SPECTRA UNFOLDING ♦ TIME-OF-FLIGHT METHOD ♦ VERIFICATION
Abstract Verification of future warhead-dismantlement treaties will require detection of certain warhead attributes without the disclosure of sensitive design information, and this presents an unusual measurement challenge. Neutron spectroscopy—commonly eschewed as an ill-posed inverse problem—may hold special advantages for warhead verification by virtue of its insensitivity to certain neutron-source parameters like plutonium isotopics. In this article, we investigate the usefulness of unfolded neutron spectra obtained from organic-scintillator data for verifying a particular treaty-relevant warhead attribute: the presence of high-explosive and neutron-reflecting materials. Toward this end, several improvements on current unfolding capabilities are demonstrated: deuterated detectors are shown to have superior response-matrix condition to that of standard hydrogen-base scintintillators; a novel data-discretization scheme is proposed which removes important detector nonlinearities; and a technique is described for re-parameterizing the unfolding problem in order to constrain the parameter space of solutions sought, sidestepping the inverse problem altogether. These improvements are demonstrated with trial measurements and verified using accelerator-based time-of-flight calculation of reference spectra. Then, a demonstration is presented in which the elemental compositions of low-Z neutron-attenuating materials are estimated to within 10%. These techniques could have direct application in verifying the presence of high-explosive materials in a neutron-emitting test item, as well as other for treaty verification challenges.
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 2016-08-14
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 120
Issue Number 6


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