Measurement of the Neutron Capture Cross Section of Holmium-165 and Gold-197

As part of a continuing program to accurately measure neutron capture cross sections, we have obtained data for 165Ho and 197Au in the 167-eV to 0.6-MeV energy range. All capture reactions are measured relative to the fission rate of 235U for neutron energies above 800 eV and to the 10B(n, αo + α1) reaction below 13 keV. In addition, current best estimates of σF(235U) and σn,α(10B) are used to convert these ratios to up-to-date capture cross sections. The 3.9-eV “black resonance” of 165Ho is used to normalize all cross sections.