Spectrum of the ReactionPb208(n,γ)Pb209and Semidirect Capture Theory

Abstract

Measurements of the spectrum of $\gamma$ rays from the reaction ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}(n,\gamma ){}_{}{}^{209}{}_{}{}^{}\mathrm{Pb}$ have been made at incident neutron energies of 9.2, 11.2, and 13.2 MeV. The observed spectral shapes disagree strongly with the predictions of compound-nuclear theory and agree quite well with those predicted by semidirect (collective) capture theory.