Yermolenko R. Investigation of 181Ta(n,g) Reaction Cross-sections Using the Differential Method For g-spectra

The thesis is dedicated to investigation of 181Та(n, g) reaction cross-sections using the differential method for g- spectra forming. While the work performance it was mathematically proved and experimentally confirmed a possibility to apply a differential method for measurements of high-level and variable in-time nuclear radiation fluxes. The scope for application of this method and the uncertainties due it's using are investigated and established. The reaction 181Та (n,g)182m2Та cross-sections have been measured for 1.9 kеV; 59 kеV; 144.5 kеV та 2.85 MеV incident neutron energies for a first time. The reaction 181Та (n,g)182m2Та cross-section for 14.34 MеV incident neutron energy as well as the reaction 181Та(n, g) 182gТа cross-section value for 2.85 MеV incident neutron energy values obtained have significantly improved the existing experimental information. Additionally with using the EMPIRE II code there were 181Та(n,g) cross-section calculations performed to study an influence of calculation parameters on cross-section values. The most acceptable agreement with experimental data does correspond to using BCS + Fermi-gas model (Empire II) for nuclear level densities, Bersillon optical potential, dipole radiative strength functions MLO1 and EGLO and taking into account -transition multipolarity <=3.