Neutron scattering from Au,Hg, and Tl

The elastic and the inelastic scattering of fast neutrons from Au, Hg, and Tl was studied at incident neutron energy intervals of ~50 keV from 0.3 to 1.5 MeV. The differential elastic scattering cross sections were determined approximately every fifteen degrees from 20 to 145 degrees. The cross sections for the inelastic excitation of states in Au at 77, 270, 409, 520, 540, 740, 830, 940, 1120, and 1220 keV; in Hg at 160, 208, 440, 610, 980, and 1120 keV; and in Tl at 205, 279, 615, 680, 930, and 1080 keV were determined. The measured elastic scattering cross sections were compared with the results of optical model calculations and evidence for a decrease in the imaginary part of the potential near the doubly closed shell atA=208 was observed. The results of Hauser-Feshbach calculations, utilizing known spin and parity assignments together with those estimated from nuclear systematics, were in qualitative agreement with the measured inelastic excitation functions. The effect of resonance width fluctuations was considered in the context of the experimental results.