Absolute Measurements of the ¹⁹⁷Au(n, γ)¹⁹⁸Au Cross Section for Fast Neutrons

Neutron capture cross sections for the ¹⁹⁷Au(n, γ)¹⁹⁸Au reaction have been absolutely determined at neutron energies of 23 and 967 keV. These are the median energies of the two photoneutron sources, Sb-Be and Na-Be, applied in this study. Reaction rates were determined by gamma counting of the ¹⁹⁸Au activity using a pair of cylindrical NaI(Tl) detectors. The detection efficiency of the detectors was determined using 4π beta-gamma coincidence counting techniques. The neutron emission rates of the photoneutron sources were determined by indirect comparison with the U.S. National Bureau of Standards NBS-I neutron standard source using the University of Michigan manganese bath. The values obtained for the ¹⁹⁷Au(n,γ)¹⁹⁸Au cross section are 617.8 ± 11.1 mb and 99.7 ± 2.8 mb at 23 and 967 keV, respectively.