A Hierarchical Bayesian Approach to Neutron Spectrum Unfolding With Organic Scintillators

Zhu, Haonan; Altmann, Yoann; Fulvio, Angela Di; McLaughlin, Stephen; Pozzi, Sara A.; Hero, Alfred O.

doi:10.1109/tns.2019.2941317

Cited by 18 publications

(6 citation statements)

References 43 publications

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“…Effectively shielding SNMs and intense gamma-ray emitting radionuclides, such as 137 Cs and 60 Co, would require a combination of lowand high-atomic-number elements. The current algorithm could be enhanced by coupling it to spectra reconstruction methods that we have recently developed 21 , to account for the spectral effect of shielding materials, given their known gamma-ray and neutron attenuation coefficients, as proposed by Lawrence and colleagues 22 . It should also be noted that containers carrying covert or overt amounts of metal are likely to prompt secondary inspections.…”

Section: Discussionmentioning

confidence: 99%

Expectation-propagation for weak radionuclide identification at radiation portal monitors

Altmann

Fulvio

Paff

et al. 2020

Sci Rep

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We propose a sparsity-promoting Bayesian algorithm capable of identifying radionuclide signatures from weak sources in the presence of a high radiation background. the proposed method is relevant to radiation identification for security applications. In such scenarios, the background typically consists of terrestrial, cosmic, and cosmogenic radiation that may cause false positive responses. We evaluate the new Bayesian approach using gamma-ray data and are able to identify weapons-grade plutonium, masked by naturally-occurring radioactive material (noRM), in a measurement time of a few seconds. We demonstrate this identification capability using organic scintillators (stilbene crystals and EJ-309 liquid scintillators), which do not provide direct, high-resolution, source spectroscopic information. Compared to the EJ-309 detector, the stilbene-based detector exhibits a lower identification error, on average, owing to its better energy resolution. organic scintillators are used within radiation portal monitors to detect gamma rays emitted from conveyances crossing ports of entry. the described method is therefore applicable to radiation portal monitors deployed in the field and could improve their threat discrimination capability by minimizing "nuisance" alarms produced either by noRMbearing materials found in shipped cargoes, such as ceramics and fertilizers, or radionuclides in recently treated nuclear medicine patients.The growing terrorism threat based on the use of special nuclear materials (SNMs), i.e., highly enriched uranium (HEU), weapons-grade plutonium (WGPu), or high-activity radiological sources has reinforced the need for improved population protection mechanisms. Nuclear security aims to deter and detect the smuggling of these materials across state borders. One major defense mechanism involves the installation of radiation portal monitors (RPMs) at border crossings. These RPMs typically consist of 3 He proportional counters embedded in polyethylene for neutron detection, and slabs of polyvinyl-toluene (PVT) scintillators for gamma-ray detection. Only a tiny fraction of the millions of vehicles and cargo containers entering a country like the United States are likely to be carrying radiological contraband. The International Atomic Energy Agency's Incident and Trafficking Database (ITDB) merely counts a few dozen reported successful interdictions of nuclear and radiological materials globally per year 1,2 . The ITDB provides only a partial picture of the number of smuggling attempts. The reported figures should be considered a lower bound of the number of successful interdictions, because they include only successful interdictions, voluntarily reported by the member states.Complicating matters, the radiological contraband might be well shielded. In 2017, the United Nations Conference on Trade and Development estimated the global container port throughput at over 750 million 20-foot equivalent units 3 . As a consequence, RPMs are limited in measurement time to minimize unnecessary impediments to the fl...

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Section: Discussionmentioning

confidence: 99%

Expectation-propagation for weak radionuclide identification at radiation portal monitors

Altmann

Fulvio

Paff

et al. 2020

Sci Rep

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“…The expected utility of the insider adopting the strategy of implementing malicious behaviors is assumed to be U A1 , as shown in Equation (7). According to Equation (2), the expected utility function of the insiders' RDEU model is V A (X, u, W), as shown in Equation (8).…”

Section: Strategic Benefits Of Insiders U(x I )mentioning

confidence: 99%

“…However, the radioactivity of nuclear products such as uranium dioxide and plutonium dioxide is very low; these are packaged in containers and accessible to personnel [7]. If nuclear materials and technology were acquired by insiders, it would have disastrous consequences [8,9]. Therefore, how to effectively deal with nuclear security incidents from internal threats is an urgent problem to be solved in the physical protection supervision of spent fuel reprocessing plants.…”

Section: Introductionmentioning

confidence: 99%

Evolutionary Game Model of Internal Threats to Nuclear Security in Spent Fuel Reprocessing Plants Based on RDEU Theory

Zou

Jia-hua³

2022

Sustainability

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The internal threat to nuclear security is one of the most serious problems in the physical protection supervision of spent fuel reprocessing plants. Both insiders and nuclear security departments have obvious characteristics of situational decision making and even irrational decision making. Combined with Game theory and RDEU theory, the RDEU Game model of insiders and nuclear security departments was constructed to analyze the existence of equilibrium solutions of two-way strategies under different emotional states. From a dynamic point of view, the influence and change process of emotion on participants’ decision-making behavior were analyzed. Then, the model was numerically simulated to verify its accuracy and effectiveness, which showed that different emotional states and intensities would not only affect the final result of evolutionary equilibrium, but also change the evolution speed of the strategies. In addition, compared with insiders, the intensity of pessimism in the nuclear security department had a greater impact on the game equilibrium. Finally, we present some reasonable recommendations to prevent and protect nuclear security events at spent fuel reprocessing plants by strengthening the emotional supervision and guidance of insiders and the nuclear security department.

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“…This process is described mathematically in Equation 5 and further detailed in our previous work [15].…”

Section: Unfolding Algorithm and Spectroscopy Metricsmentioning

confidence: 99%

Characterization of stilbene-d12 for neutron spectroscopy without time of flight

Gaughan,

Zhou,

Becchetti

et al. 2021

Preprint

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We have experimentally characterized the light-output response of a deuterated trans-stilbene (stilbene-d 12 ) crystal to quasi-monoenergetic neutrons in the 0.8 to 4.4 MeV energy range. These data allowed us to perform neutron spectroscopy measurements of a DT 14.1 MeV source and a 239 PuBe source by unfolding the impinging neutron spectrum from the measured light-output response. The stilbene-d 12 outperforms a 1 H-stilbene of similar size when comparing the shape of the unfolded spectra and the reference ones. These results confirm the viability of non-hygroscopic stilbene-d 12 crystal for direct neutron spectroscopy without need for time-of-flight measurements. This capability makes stilbene-d 12 a well suited detector for fast-neutron spectroscopy in many applications including nuclear reaction studies, radiation protection, nuclear non-proliferation, and space travel.

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A Hierarchical Bayesian Approach to Neutron Spectrum Unfolding With Organic Scintillators

Cited by 18 publications

References 43 publications

Expectation-propagation for weak radionuclide identification at radiation portal monitors

Expectation-propagation for weak radionuclide identification at radiation portal monitors

Evolutionary Game Model of Internal Threats to Nuclear Security in Spent Fuel Reprocessing Plants Based on RDEU Theory

Characterization of stilbene-d12 for neutron spectroscopy without time of flight

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