High-accuracy 233U(n,f) cross-section measurement at the white-neutron source n_TOF from near-thermal to 1 MeV neutron energy

M. Calviani , J. Praena , U. Abbondanno , G. Aerts (1) , H. Álvarez , F. Álvarez-Velarde , S. Andriamonje (1) , J. Andrzejewski , P. Assimakopoulos , L. Audouin (2) , G. Badurek , P. Baumann (3) , F. Bečvář , F. Belloni , B. Berthier (2) , E. Berthoumieux (1) , F. Calviño , D. Cano-Ott , R. Capote , C. Carrapiço (1, 2) , P. Cennini , V. Chepel , E. Chiaveri , N. Colonna , G. Cortes , A. Couture , J. Cox , M. Dahlfors , S. David (2) , I. Dillmann , C. Domingo-Pardo , W. Dridi (1) , I. Duran , C. Eleftheriadis , M. Embid-Segura , L. Ferrant , Anthony Ferrari , R. Ferreira-Marques , K. Fujii , W. Furman , I. Goncalves , E. González-Romero , A. Goverdovski , F. Gramegna , C. Guerrero , F. Gunsing (1) , B. Haas (4) , R. Haight , M. Heil , A. Herrera-Martinez , M. Igashira , E. Jericha , F. Käppeler , Y. Kadi , D. Karadimos , D. Karamanis , V. Ketlerov , M. Kerveno (3) , P. Koehler , V. Konovalov , E. Kossionides , M. Krtička , C. Lampoudis , H. Leeb , A. Lindote , I. Lopes , M. Lozano , S. Lukic (3) , J. Marganiec , S. Marrone , T. Martínez , C. Massimi , P. Mastinu , A. Mengoni , P. M. Milazzo , C. Moreau , M. Mosconi , F. Neves , H. Oberhummer , S. O'Brien , J. Pancin (1) , C. Papachristodoulou , C. Papadopoulos , C. Paradela , N. Patronis , A. Pavlik , P. Pavlopoulos (5) , L. Perrot (1) , M. T. Pigni , R. Plag , A. Plompen , A. Plukis (1) , A. Poch , C. Pretel , J. Quesada , T. Rauscher , R. Reifarth , M. Rosetti , C. Rubbia , G. Rudolf (3) , P. Rullhusen , J. Salgado , C. Santos , L. Sarchiapone , I. Savvidis , C. Stephan (2) , G. Tagliente , J. L. Tain , L. Tassan-Got (2) , L. Tavora , R. Terlizzi , G. Vannini , P. Vaz , A. Ventura , D. Villamarin , M. C. Vincente , V. Vlachoudis , R. Vlastou , F. Voss , S. Walter , M. Wiescher , K. Wisshak

1 DAPNIA - Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée
2 IPNO - Institut de Physique Nucléaire d'Orsay
3 IReS - Institut de Recherches Subatomiques
4 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan
5 Pôle Universitaire Léonard de Vinci

The 233U(n,f) cross section has been measured at the white neutron source n_TOF in a wide energy range with a dedicated fission ionization chamber. We report here the results from ~30 meV to 1 MeV neutron energy. The 233U(n,f) cross section has been determined relative to a reference sample of 235U(n,f) measured simultaneously with the same detector. The very high instantaneous neutron flux and the intrinsically low background of the n_TOF installation result in an accuracy around 3% in the whole energy range, while the energy resolution of the neutron beam allows for an accurate description of the fission cross section by means of R-matrix analysis over a wide energy range. The results are, in general, in good agreement with the most recent high-accuracy measurement of this fission cross section, over the more limited range of the previous measurements, and indicated that even the latest evaluations underestimate the cross section in the epithermal region. The present high-quality data provide the basis for a more precise evaluation of the 233U fission cross section and for improving the reliability of databases needed for the design of new energy systems based on the Th/U cycle.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

M. Calviani, J. Praena, U. Abbondanno, G. Aerts, H. Álvarez, et al.. High-accuracy 233U(n,f) cross-section measurement at the white-neutron source n_TOF from near-thermal to 1 MeV neutron energy. Physical Review C, 2009, 80, pp.044604 [11]. ⟨10.1103/PhysRevC.80.044604⟩. ⟨in2p3-00431894⟩