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, α_o + 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.