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

Abstract

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, σ 0, and resonance integrals, I 0, 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 σ 0 = 98.65 ± 0.09 barn and I 0 = 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 σ 0 = 0.424 ± 0.018 barn and I 0 = 6.35 ± 0.45 barn for the 179Hf(n,γ) 180mHf reaction, and σ 0 = 12.87 ± 0.52 barn and I 0 = 32.91 ± 2.38 barn for the 180Hf(n,γ) 181Hf reaction. The present results are in good agreement with recent measurements.