Evaluation of the 23Na(N,Gamma) Reaction Cross Section

Abstract

Poor and incomplete uncertainty information for the 23Na(n,g)24Na reaction cross-section evaluation in the International Reactor Dosimetry and Fusion File, new thermal neutron capture cross-section measurements, and recent advances in evaluation techniques have stimulated a revision of the International Reactor Dosimetry and Fusion File evaluation. The basic characteristics of the new evaluation are as follows: The evaluated thermal cross section is about 2.5 % higher than the value recommended by Mughabghab. In the resolved resonance region, the evaluated cross section is parameterized by the Reich-Moore formula without a background contribution. In the high-energy region, the evaluated values had been calculated using a PADE2 code on the basis of the experimental data and the results of theoretical model calculations. The new evaluation contains complete cross-section covariance information and provides a better agreement with both the differential and integral experimental cross-section data.