Calculation of neutron capture γ-ray spectra including giant resonance effects

Abstract

Neutron capture γ-ray spectra were calculated with an electric dipole γ-ray strength function derived through extrapolation of the E1 giant resonance to lower energies. To obtain agreement with experiment for such elements as Cs and Au it was necessary to assume a second peak in the γ-ray strength function at an energy of about 5.5 MeV. The position of this peak and the absolute value as well as the dependence on mass number of its strength indicate that it may be the M1 giant resonance predicted by Mottelson.