Browsing by Subject "Nuclear counters"
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Item Analysis of smuggler movement on multiple transportation networks(2011-05) Goshev, Stefan Antoanov; Morton, David P.; Popova, ElmiraWe analyze an interdiction problem in which a nuclear-material smuggler can traverse multiple transportation networks, wherein each edge has an indigenous probability of evasion. Our objective is to determine the optimal locations of a limited number of radiation detectors at United States ports of entry across multiple networks (maritime, road and rail) so as to minimize the smuggler's total probability of evasion, from origin to destination. We choose geographically diverse potential origins and give the smuggler freedom to move across and between transportation networks. Further, we consider two different models of smuggler behavior in this context. Our analysis aims to provide a complete prioritization and picture of the threat at all ports of entry, leading to insight into good practical locations for detectors.Item Production of [beta-gamma] coincidence spectra of individual radioxenon isotopes for improved analysis of nuclear explosion monitoring data(2008-08) Haas, Derek Anderson, 1981-; Biegalski, Steven R.Radioactive xenon gas is a fission product released in the detonation of nuclear devices that can be detected in atmospheric samples far from the detonation site. In order to improve the capabilities of radioxenon detection systems, this work produces [beta-gamma] coincidence spectra of individual isotopes of radioxenon. Previous methods of radioxenon production consisted of the removal of mixed isotope samples of radioxenon gas released from fission of contained fissile materials such as ²³⁵U. In order to produce individual samples of the gas, isotopically enriched stable xenon gas is irradiated with neutrons. The detection of the individual isotopes is also modeled using Monte Carlo simulations to produce spectra. The experiment shows that samples of [superscript 131m]Xe, ¹³³Xe, and ¹³⁵Xe with a purity greater than 99% can be produced, and that a sample of [superscript 133m]Xe can be produced with a relatively low amount of ¹³³Xe background. These spectra are compared to models and used as essential library data for the Spectral Deconvolution Analysis Tool (SDAT) to analyze atmospheric samples of radioxenon for evidence of nuclear events.