Thermal neutron cross section determination of short-to-medium lived nuclides using a 20 Ci Am–Be neutron source

While there are growing demands for the nuclear data at higher energy regions than keV for up-to-date scientific and technological development, accurate capture cross sections at thermal energy are still needed. The thermal neutron capture cross sections for the reactions 127I(n,γ)128I, 152Sm(n,γ)153Sm,154Sm(n,γ)155Sm, and 238U(n,γ)239U were determined by the method of foil activation using 55Mn(n,γ)56Mn as a reference reaction. The experimental samples with and without a Cd cover were irradiated in an isotropic neutron field of a 20 Ci 241Am–Be neutron source facility. A high purity Ge detector was used to measure the induced gamma-rays from the samples and the monitor. The thermal neutron capture cross sections of the reactions 127I(n,γ)128I, 152Sm(n,γ)153Sm, 154Sm(n,γ)155Sm, and 238U(n,γ)239U were deduced from the analysis of obtained gamma-ray spectra. The thermal neutron capture cross section values for 127I(n,γ)128I, 152Sm(n,γ)153Sm, 154Sm(n,γ)155Sm, and 238U(n,γ)239U reactions are (5.93 ± 0.52), (207.3 ± 9.4), (7.7 ± 0.3), and (2.79 ± 0.09) barns respectively. The obtained results have been discussed and compared with the available experimental data and were found to be in agreement with each other.

► Am–Be neutron source was used to measure cross sections using activation method. ► 55Mn(n,γ)56Mn was used as the reference reaction for the measurement. ► The thermal neutron cross sections of 128I, 153Sm, 155Sm, and 239U were measured. ► The obtained results are in a good agreement within the experimental uncertainty.