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A new computer code for the determination of the isotope composition of actinides by X- and gamma ray spectrometry and its applications

Abstract : Since 1998 CEA and COGEMA have been collaborating on new tools for isotope analysis by X- and gamma ray spectrometry with germanium detectors. The research program started with the determination of plutonium isotope composition, knowledge of which is essential in several branches of the nuclear industry. The newly developed application is characterised by an original approach and innovative gamma ray spectrometry techniques featuring: - a generic design (for example, no distinction is made between the analysis of the different isotopes of plutonium); - the systematic and automatic use of an atomic and nuclear database; - an advanced constrained-optimisation algorithm expressing physical knowledge in terms of constraints thus allowing robust analysis of very complex regions of interest; - the simultaneous determination of global efficiency curve and isotope ratios. For a user, this application takes form of an entirely automatic tool that accepts spectra corresponding to any experimental setup (gain, energy range, resolution, screen etc), without any detailed data on the setup being necessary. Moreover the user can control all intermediate results by the way of a user-friendly interface through an Internet browser. As the performance of the application proved satisfactory for plutonium isotopes in terms of robustness and precision, it was decided to extend it first to uranium enrichment, then to uranium and plutonium mixtures, and more generally to any actinide and contaminant mixtures. The development and evolution of the enhanced tool proceeded smoothly due to its initial generic design. In addition, a specific peak-location module was developed. This can recognize isotopes in a spectrum, and orientate the treatment to different classes such as 'plutonium spectrum', 'uranium spectrum', or 'mixture spectrum'. The application, called IGA, can now recognize and analyse a spectrum with actinides such as plutonium, uranium, neptunium and curium, together or alone, and in the presence of contaminants. The same set of algorithms has been also applied to another purpose, the characterisation of waste packages. A dedicated tool, called IGA/Sandra, has been developed for the CEA centre at Fontenay aux Roses. This tool is able to compute not only isotopic ratios and relative efficiency but also absolute activities, by normalisation with measured efficiency. Another domain of application of IGA is spectrum analysis from CdTe, CZT and NaI detectors. The peak location module already gives good results, since it is able to adapt itself to each type of detector and to find peaks in this type of spectrum.
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Contributor : Bruno Savelli <>
Submitted on : Friday, January 12, 2018 - 11:42:16 AM
Last modification on : Monday, February 10, 2020 - 6:12:35 PM


  • HAL Id : cea-01682396, version 1




Anne-Catherine Simon, Jean-Pierre Both, Isabelle Espagnon, Jean Lefevre,, Vincent Picaud,, et al.. A new computer code for the determination of the isotope composition of actinides by X- and gamma ray spectrometry and its applications. European nuclear conference. Nuclear power for the 21. century: from basic research to high-tech industry, Dec 2005, Versailles, France. ⟨cea-01682396⟩



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