High-Resolution Study of $^{237}$Np Fission Cross Section from 5 eV to 1 MeV

W. Furman , P. Cennini , V. Ketlerov , A. Goverdovski , V. Konovalov , U. Abbondanno , G. Aerts , H. Álvarez , F. Alvarez-Velarde , S. Andriamonje , J. Andrzejewski , P. Assimakopoulos , L. Audouin (1) , G. Badurek , P. Baumann (2) , F. Becvár , J. Benlliure , E. Berthoumieux , F. Calviño , D. Cano-Ott , R. Capote , A. Carrillo de Albornoz , V. Chepel , E. Chiaveri , N. Colonna , G. Cortes , D. Cortina , A. Couture , J. Cox , S. David (1) , R. Dolfini , C. Domingo-Pardo , A. Dorochenko , W. Dridi , I. Duran , M. Embid-Segura , L. Ferrant (1) , Anthony Ferrari , R. Ferreira-Marques , L. Fitzpatrick , H. Frais-Koelbl , K. Fujii , C. Guerrero , I. Goncalves , R. Gallino , E. Gonzalez-Romero , F. Gramegna , E. Griesmayer , F. Gunsing , B. Haas (3) , R. Haight , M. Heil , A. Herrera-Martinez , M. Igashira , S. Isaev (1) , E. Jericha , Y. Kadi , F. Käppeler , D. Karamanis , D. Karadimos , M. Kerveno (2) , P. Koehler , D. Kolokolov , E. Kossionides , M. Krticka , C. Lamboudis , H. Leeb , A. Lindote , I. Lopes , M. Lozano , S. Lukic (2) , J. Marganiec , L. Marques , S. Marrone , P. Mastinu , A. Mengoni , P. M. Milazzo , C. Moreau , M. Mosconi , F. Neves , H. Oberhummer , S. O'Brien , M. Oshima , J. Pancin , C. Papachristodoulou , C. Papadopoulos , C. Paradela , N. Patronis , A. Pavlik , P. Pavlopoulos , L. Perrot , R. Plag , A. Plompen , A. Plukis , A. Poch , C. Pretel , J. Quesada , T. Rauscher , R. Reifarth , M. Rosetti , C. Rubbia , G. Rudolf (2) , P. Rullhusen , J. Salgado , L. Sarchiapone , M. Sedysheva , C. Stephan (1) , G. Tagliente , J. L. Tain , L. Tassan-Got (1) , L. Tavora , R. Terlizzi , G. Vannini , P. Vaz , A. Ventura , D. Villamarin , M. C. Vincente , V. Vlachoudis , R. Vlastou , F. Voss , H. Wendler , M. Wiescher , K. Wisshak

1 IPNO - Institut de Physique Nucléaire d'Orsay
2 IReS - Institut de Recherches Subatomiques
3 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan

A series of measurements of 237Np fission cross section have been performed at the CERN spallation neutron facility n_TOF which covers a wide energy range from 1 eV up to 250 MeV. A fast ionization chamber (FIC) was used as a fission fragment detector with registration efficiency of not less than 97 %. Particular attention was paid to correct the fission cross section with use of 235U standard. Total experimental uncertainties are determined to be at the level of 3%. Analysis of the experimental data in the restricted neutron energy from 5 eV up to 1 MeV showed a systematic deviation from evaluated data (ENDF/B-VI). This discrepancy amounts to up to a factor 3 for resolved resonances in the neutron energy range of 5 eV - 2 KeV, and is in good agreement with some previous experiments. A similar disagreement at the level of 6-7% was found for higher energies around the threshold (En = 300 keV-1 MeV). This energy range is essential for the transmutation of neptunium in ADS or fast reactors. It is concluded that an updated evaluation of nuclear data for 237Np is required

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

W. Furman, P. Cennini, V. Ketlerov, A. Goverdovski, V. Konovalov, et al.. High-Resolution Study of $^{237}$Np Fission Cross Section from 5 eV to 1 MeV. International Conference on Nuclear Data for Science and Technology, Sep 2004, Santa Fe, United States. pp.1039-1042, ⟨10.1063/1.1945184⟩. ⟨in2p3-00025890⟩