This paper is sequential to studies discussing with the impact of the Doppler broadening of the Double Differential Cross Section (DDXS) on nuclear reactor core calculations. In this study, the ...influence of the resonance dependent DDXS on the observed resonance line shape in time of flight capture experiments is investigated. The importance of the correct formalism is illustrated by comparing Monte Carlo simulations with and without a resonance dependent DDXS model to measured data of a saturated 238U resonance. The resonance dependent DDXS is taken into account via its stochastic implementation known as Doppler Broadening Rejection Correction (DBRC). In addition, the increased impact of the resonance dependent DDXS model for higher temperatures is shown via a simulation of capture yields for 238U and 183W at different sample temperatures.
We generated a preliminary set of resonance parameters for 182,183,184,186W in the neutron energy range of thermal up to several keV. The evaluation methodology uses the Reich-Moore approximation to ...fit with the R-matrix code SAMMY, the high-resolution measurements performed in 2010 and 2012 at the Geel linear accelerator facility. For 183W, the transmission data and capture cross sections calculated with the set of resonance parameters are compared with the experimental values, and some of the average properties of the resonance parameters are discussed. In the analyzed energy range, this work almost doubles the existing resolved resonance evaluations in the ENDF/B-VII.1 library. A preliminary analysis of the performance of the calculated cross sections based on Lead slowing-down benchmarks is presented and briefly discussed.
Over the last decade, the EC–JRC–IRMM, in collaboration with other institutes such as INRNE Sofia (BG), INFN Bologna (IT), ORNL (USA), CEA Cadarache (FR) and CEA Saclay (FR), has made an intense ...effort to improve the quality of neutron-induced cross section data in the resonance region. These improvements relate to both the infrastructure of the facility and the measurement setup, and the data reduction and analysis procedures. As a result total and reaction cross section data in the resonance region with uncertainties better than 0.5 % and 2 %, respectively, can be produced together with evaluated data files for both the resolved and unresolved resonance region. The methodology to produce full ENDF compatible files, including covariances, is illustrated by the production of resolved resonance parameter files for 241Am, Cd and W and an evaluation for 197Au in the unresolved resonance region.
Neutron capture cross sections are the key nuclear physics input to study the slow neutron capture process, which is responsible for forming about half of the elemental abundances above Fe. Stellar ...neutron capture cross section can be measured by the time-of-flight technique, or by activation. Both techniques will be discussed and recent experiments in the Fe Ni mass region will be presented.
The (n, α) reaction in the radioactive {sup 59}Ni is of relevance in nuclear astrophysics as {sup 59}Ni can be considered as the first branching point in the astrophysical s-process. Its relevance in ...nuclear technology is especially related to material embrittlement in stainless steel. However, there is a discrepancy between available experimental data and the evaluated nuclear data files for this reaction. At the n{sub T}OF facility at CERN, a dedicated system based on sCVD diamond diodes was set up to measure the {sup 59}Ni(n, α){sup 56}Fe cross section. The results of this measurement, with special emphasis on the dominant resonance at 203 eV, are presented here.
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