Measurements of neutron capture cross-sections for nuclides of interest in decommissioning (IV): ¹⁶⁵Ho(n, γ)^{166m, 166g}Ho reactions

During the decommissioning of nuclear facilities, large amounts of radioactive wastes are generated from structural materials. When considering the disposal or reuse of such wastes, accurate neutron capture cross-sections are required to evaluate the amounts of radioactive nuclides among the wastes. The present work selected ¹⁶⁵Ho among nuclides included in the list for clearance levels in decommissioning and measured the thermal-neutron capture cross-sections for the ¹⁶⁵Ho(n, γ)^166mHo, ^166gHo reactions by the neutron activation method. The thermal cross-section measurements were performed with the graphite thermal column of the Kyoto University Research Reactor under the 5-MW operation and the thermal-neutron capture cross-sections were derived on the basis of <i>Westcott</i>’s convention. In this work, a value of 2.79 ± 0.04 barn was obtained for the ¹⁶⁵Ho(n,γ)^166mHo reaction, and 61.2 ± 0.6 barn for the ¹⁶⁵Ho(n,γ)^166gHo reaction. The combination of these cross-sections presented 64.0 ± 0.6 barn, which supports the recent evaluated data of 64.69 barn and 64.4 ± 1.2 barn within the limit of uncertainties.