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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-24 23:12 |
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Conference: Bucharest University Faculty of Physics 2018 Meeting
Section: Nuclear and Elementary Particles Physics
Title:
Nuclear Forensics Analysis of Highly Enriched Uranium by Gamma Spectrometry
Authors:
Larisa GANEA(1), Andrei APOSTOL(2), Andreea SERBAN(1,2)
*
Affiliation:
1)Faculty of Physics, University of Bucharest
2) Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH)
E-mail
larisa1994g@yahoo.com
Keywords:
Nuclear Forensics , Highly Enriched Uranium, Gamma Spectrometry
Abstract:
After the dispersion of highly enriched uranium (HEU) as a result of unsuccessful detonation of an Improvised Nuclear Device (IND), where no chain reaction was caused due to various reasons, the prompt analysis and also the preservation of the evidence contained by the spread nuclear materials is essential for subsequent case investigation.
This research is focused on the two main directions: the identification of nuclear forensics signatures which might be obtained non-destructively and their accurate measurement using gamma spectrometry.
The outcomes of this research can be used to answer the emergent prosecutors questions about the material’s origin. Those outcomes are based on the determination of the following nuclear forensics signatures: isotopic composition, age (the time passed since the last chemical separation of the nuclear material) and reprocessed uranium concentration.
Four HEU samples were analyzed using four Hyper-Pure Germanium (HPGe) detectors and two automated computer codes.
The isotopic composition of the HEU samples was estimated with MGAU v4.2 and PC/FRAM v5.1.
A new gamma spectrometric method for age-dating of HEU samples was developed and tested. This method is based on granddaughter/parent activity ratio - 227Ac/235U. To confirm the accuracy of the new developed method, the obtained results were compared with the outcomes from a described in the literature non-destructive method for the age dating – 214Bi/234U chronometer. In both cases, the activity ratios used for for the estimation of age values were obtained using the intrinsic efficiency of the detectors.
In order to link the samples between each other, all the analyzed signatures were compared for the four studied samples.
References:
[1] Andrei I. Apostol, Applications of Gamma Spectrometry and Particle Accelerators in the Field of Nuclear Forensics , 2017 (PhD Thesis)
[2] Andrei I. Apostol, Ana Pantelica, Octavian Sima, Viorel Fugaru, Isotopic Composition Analysis and Age Dating of Uranium Samples by High Resolution Gamma Ray Spectrometry, Nucl. Instr. Meth. B 383 (2016) 103-108
[3] C.T. Nguyen, Age-dating of highly enriched uranium by gamma-spectrometry, Nucl. Instr. Meth. B 229 (2005) 103-110.
[4] Ross Williams, Amy Gaffney, Michael Kristo, Radiochronometry Guidance LLNL-TR-701379, 2016
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