Ядерна фізика та енергетика Nuclear Physics and Atomic Energy   ISSN: 1818-331X (Print), 2074-0565 (Online)   Publisher: Institute for Nuclear Research of the National Academy of Sciences of Ukraine   Languages: Ukrainian, English   Periodicity: 4 times per year   Open access peer reviewed journal

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O. Zhukov¹, V. Lebed^1,2, I. Maliuk¹, M. Strilchuk^1,*, V. Tryshyn<sup>1

1</sup> Institute for Nuclear Research, National Academy of Sciences of Ukraine, Kyiv, Ukraine
² Taras Shevchenko National University of Kyiv, Kyiv, Ukraine

^*Corresponding author. E-mail address: myst@meta.ua

Abstract: The value of absolute emission probabilities from the decay of ²³⁵U in the energy range of 200-450 keV was refined by using semiconductor gamma spectrometry with a reference material containing highly enriched uranium and mathematical modelling of the measurement geometry. This refinement is essential for the accurate gamma-spectrometric determination of characteristics (signatures) of highly enriched uranium that are crucial for nuclear forensics, such as model age and ²²⁸Th impurity. This clarification is also useful from the point of view of fundamental nuclear physics, as it introduces significant changes in the data concerning the ²³¹Th level scheme from the alpha decay of ²³⁵U.

Keywords: ²³⁵U, nuclear forensics, highly enriched uranium, model age, gamma spectrometry, absolute emission probability.

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