The activation cross section measurements of proton-induced reactions on Li and Ta in the energy region 12.5–34 MeV

Abstract

The experimental data on cross sections are necessary to clarify existing ideas on the mechanisms of nuclear reactions and for testing of nuclear models. Proton-induced reaction on 7Li serves as a source of quasi-monoenergetic neutrons which are widely used in the measurement of cross sections for neutron induced reactions. Tantalum plays an important role in technology and nuclear facilities mainly for its low induced activity (screens, degraders). In order to investigate the important nuclides, we have carried out the irradiation experiments with the variable-energy cyclotron U-120M of the NPI CAS Řež. The cross section of the reaction 7Li(p,n)7Be(ground state+0.43 MeV) and the cross sections of the nuclides 180,178mTa, 178W and 175Hf from reactions on natural tantalum were investigated, of which 181Ta(p,n)180gTa for the first time. The stacked-foil technique was utilized. The comparison of new results with prior data and predictions of evaluations is discussed.