Measurement of natNi(γ, xn)57,56Ni and natNi(γ, pxn)58−55Co reaction cross sections in bremsstrahlung with end-point energies of 65 and 75 MeV

Abstract

The cross sections of natNi(γ, xn)57,56Ni and natNi(γ, pxn)58−55Co reactions induced by bremsstrahlung end-point energies of 65 and 75 MeV were measured by using the method of activation along with off-line γ-ray spectrometric technique. The natNi(γ, xn)57,56Ni and natNi(γ, pxn)58−55Co reaction cross sections as a function of photon energy were also calculated by using TALYS 1.9 code. The flux-weighted average values at different end-point energies were obtained from the literature data, as well as from the theoretical values of TALYS and TENDL-2017 data library based on mono-energetic photons. Those were compared with the experimental data of present work and found to be in general agreement. It was also found that the experimental and theoretical cross-sections data increase with bremsstrahlung energy up to a certain value. After that the individual reaction cross sections slightly decrease with the increase of bremsstrahlung energy due to the opening of other reactions. As an example, the natNi(γ, xn)57Ni reaction cross section decreases when the natNi(γ, xn)56Ni reaction opens up. Similarly, the natNi(γ, pxn)58Co reaction cross section decreases when natNi(γ, pxn)57Co reaction opens up and so on. These observations indicate the role of excitation energy and its portion in different reaction channels.