Measurement of thermal neutron cross-sections and resonance integrals for 179Hf(n,γ)180mHf and 180Hf(n,γ)181Hf reactions at the Pohang neutron facility

The thermal-neutron cross-sections and the resonance integrals for the 179Hf(n,γ)180mHf and the 180Hf(n,γ)181Hf reactions have been measured by the activation method. The high purity Hf and Au metallic foils within and without a Cd shield case were irradiated in a neutron field of the Pohang neutron facility. The gamma-ray spectra from the activated foils were measured with a calibrated p-type high-purity Ge detector.In the experimental procedure, the thermal neutron cross-sections, σ0, and resonance integrals, I0, for the 179Hf(n,γ)180mHf and the 180Hf(n,γ)181Hf reactions have been determined relative to the reference values of the 197Au(n,γ)198Au reaction, with σ0 = 98.65 ± 0.09 barn and I0 = 1550 ± 28 barn. In order to improve the accuracy of the experimental results, the interfering reactions and necessary correction factors were taken into account in the determinations. The obtained thermal neutron cross-sections and resonance integrals were σ0 = 0.424 ± 0.018 barn and I0 = 6.35 ± 0.45 barn for the 179Hf(n,γ)180mHf reaction, and σ0 = 12.87 ± 0.52 barn and I0 = 32.91 ± 2.38 barn for the 180Hf(n,γ)181Hf reaction. The present results are in good agreement with recent measurements.