High-resolution evaluation of the U5(n,f) cross section from 3 keV to 30 keV
1) Universidad de Santiago de Compostela, 15782, Spain
2) EC-JRC-IRMM, Retieseweg 111, B-2440 Geel, Belgium
3) CNRS/IN2P3-Université Paris-Sud- IPN, Orsay
Published online: 5 June 2019
235U neutron-induced fission cross-section is commonly used as reference for determining other isotope fission cross-section. However, below 150 keV this cross section is only included as Standard at the thermal point and recently its integral value between 7.8 eV and 11 eV . The resolved resonance region, spanning up to 2.25 keV, has been reevaluated with high resolution in the last ENDF/B-VIII release  and a SAMMY resonance analysis was done by L. Leal et al.  including the CERN-nTOF experimental work of Paradela el al.  up to 10 keV, taken into account the IAEA Reference file.
In this work the 235U(n,f) low-background and high-resolution experimental data obtained at the CERN-nTOF facility is combined with previous high-resolution experimental data, in order to produce a very fine grid dataset with normalisation to the IAEA Reference file. The extremelyhigh energy calibration required to reproduce the resonance sharp profiles is based on the nTOF DAQ system with a resolution below 0.1% with reference to the 8.78 eV resonance and to the sharp Al(n,g) capture dip at 5.904 keV.
The comparison of the so-evaluated profile with the experimental data and with the evaluated ones will be discussed.
© The Authors, published by EDP Sciences, 2019
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