Anomalies in the Charge Yields of Fission Fragments from the U ( n , f ) 238 Reaction

Fast-neutron-induced fission of 238U at an energy just above the fission threshold is studied with a novel technique which involves the coupling of a high-efficiency γ-ray spectrometer (MINIBALL) to an inverse-kinematics neutron source (LICORNE) to extract charge yields of fission fragments via γ-γ...

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Published in:Physical review letters Vol. 118; no. 22
Main Authors: Wilson, J. N., Lebois, M., Qi, L., Amador-Celdran, P., Bleuel, D., Briz, J. A., Carroll, R., Catford, W., De Witte, H., Doherty, D. T., Eloirdi, R., Georgiev, G., Gottardo, A., Goasduff, A., Hadyńska-Klęk, K., Hauschild, K., Hess, H., Ingeberg, V., Konstantinopoulos, T., Ljungvall, J., Lopez-Martens, A., Lorusso, G., Lozeva, R., Lutter, R., Marini, P., Matea, I., Materna, T., Mathieu, L., Oberstedt, A., Oberstedt, S., Panebianco, S., Podolyák, Zs, Porta, A., Regan, P. H., Reiter, P., Rezynkina, K., Rose, S. J., Sahin, E., Seidlitz, M., Serot, O., Shearman, R., Siebeck, B., Siem, S., Smith, A. G., Tveten, G. M., Verney, D., Warr, N., Zeiser, F., Zielinska, M.
Format: Journal Article
Language:English
Published: United States American Physical Society (APS) 01.06.2017
Subjects:
ATOMIC AND MOLECULAR PHYSICS
ISSN:0031-9007, 1079-7114
Online Access:Get full text
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Summary:Fast-neutron-induced fission of 238U at an energy just above the fission threshold is studied with a novel technique which involves the coupling of a high-efficiency γ-ray spectrometer (MINIBALL) to an inverse-kinematics neutron source (LICORNE) to extract charge yields of fission fragments via γ-γ coincidence spectroscopy. Experimental data and fission models are compared and found to be in reasonable agreement for many nuclei; however, significant discrepancies of up to 600% are observed, particularly for isotopes of Sn and Mo. This indicates that these models significantly overestimate the standard 1 fission mode and suggests that spherical shell effects in the nascent fission fragments are less important for low-energy fast-neutron-induced fission than for thermal neutron-induced fission. Finally, this has consequences for understanding and modeling the fission process, for experimental nuclear structure studies of the most neutron-rich nuclei, for future energy applications (e.g., Generation IV reactors which use fast-neutron spectra), and for the reactor antineutrino anomaly.
Bibliography:USDOE
Science and Technology Facilities Council (STFC), UK
AC52-07NA27344; 05P15PKCIA; 222287
LLNL-JRNL-737167
Research Council of Norway
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.118.222501