Differential measurements and an evaluation of the 59Co( n, α) 56Mn reaction cross-section

Abstract

The activation method is used to measure differential cross-sections for the 59Co( n, α) 56Mn reaction in the threshold region from 5.07 to 9.98 MeV. The results from this investigation, along with other recent experimental data from the literature, are employed to adjust the ENDF/B-V evaluation for this reaction by means of the generalized least-squares method, thereby producing a new evaluation which better reflects contemporary knowledge of the cross-section over the energy range which has been explicitly addressed by differential experiments (5.5-18 MeV). Nuclear-model calculations are also performed in order to develop a physically reasonable differential cross-section shape for extrapolation toward threshold so that this evaluation spans the entire energy range required for ENDF/B (threshold—20 MeV). Attention is given in this work to covariances, in both the measurement and evaluation processes. Finally, the resulting differential evaluation is employed in calculations of fission-spectrum averaged cross-sections which are then compared with corresponding measured values from the literature.