Comment on "Resonant and nonresonant contributions to the photoactivation of 111Cd"

Abstract

The most recent investigation of the photoactivation of isomeric nuclei reported by Kr\ifmmode \check{c}\else \v{c}\fi{}mar et al. continues to contain a strong contribution from nonresonant channels. In this Comment we report that integrated cross sections for resonant photoactivation of isomeric levels in $^{87}\mathrm{Sr}$, $^{111}\mathrm{Cd}$, and $^{113,115}\mathrm{In}$ have been calculated from recent nuclear structure data and compared to those experimental results which assert that nonresonant contributions are important. The latter have shown systematically smaller values and the amount of missing resonant strength can be correlated to the magnitude of nonresonant cross section found in these investigations. Monte Carlo simulations of realistic experimental geometries display important components in the photon fields, resulting from environmental Compton scattering, which have been omitted in previous analyses of experimental data. The strength and shape of this contribution as a function of the experimentally important parameters suggest that the data can be explained entirely on the basis of a resonant excitation mechanism without any need to introduce a nonresonant contribution.