Isotopic distribution and dependency to fission product kinetic energy for $^{241}$Pu thermal neutron-induced fission

Abstract : Nuclear fission yields are key parameters to evaluate reactor physics quantities, such as decay heat, criticality or spent fuel radiotoxicity, and for understanding fission process. Despite a significant effort allocated to measure fission yields during the last decades, the recent evaluated libraries (JEFF-3.1.1, ENDF/B-VII.1, JENDL-4.0 …) still need improvements in particular in the reduction of the uncertainties. Additionally, some discrepancies between these libraries must be explained. A common effort by the CEA, the LPSC and the ILL aim at tackling these issues by providing precise evaluation of isotopic and isobaric fission yields with the related variance-covariance matrices. Measurements for thermal neutron induced fission of 241Pu have been carried out at the ILL in Grenoble, using the LOHENGRIN mass spectrometer. This instrument allows a selection regarding the A/q and Ek/q ratios, supplying a beam of fission products of mass A, kinetic energy Ek and of ionic charge q. Coupled to Ge detectors, one can identify the fission product nuclear charge, Z, and measure its count rate to eventually determine the isotopic yield Y(A,Z) for the main isotopes of mass A for a specific Ek. By this method, several masses have been measured in order to investigate local odd-even effects. In particular, by looking at the fission yields evolution according to the fission product kinetic energy, the sharing of the total available excitation energy at scission between deformation energy and intrinsic energy is aimed to be better understood. The main isotopic yields for the masses 130, 132, 136, 137, 138, 139, 140 and 141 will be presented. In addition, preliminary results for the masses 92, 138 and 139 showing a clear evolution of isotopic yields over Ek will be discussed.
Type de document :
Communication dans un congrès
6th Workshop on Nuclear Fission and Spectroscopy of Neutron-Rich Nuclei (FISSION 2017), Mar 2017, Chamrousse, France. 〈https://indico.ill.fr/indico/event/64/〉
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Contributeur : Emmanuelle Vernay <>
Soumis le : jeudi 6 avril 2017 - 10:06:39
Dernière modification le : lundi 9 avril 2018 - 12:22:10

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  • HAL Id : in2p3-01502773, version 1

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S. Julien-Laferrière, A. Chebboubi, G. Kessedjian, O. Serot, D. Bernard, et al.. Isotopic distribution and dependency to fission product kinetic energy for $^{241}$Pu thermal neutron-induced fission. 6th Workshop on Nuclear Fission and Spectroscopy of Neutron-Rich Nuclei (FISSION 2017), Mar 2017, Chamrousse, France. 〈https://indico.ill.fr/indico/event/64/〉. 〈in2p3-01502773〉

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