Study of the Cross-Section for the 122Te(γ, n)121Te Reaction by the Activation Method

Abstract

Relevance. The study of photonuclear reactions plays a defining role in the formation of modern ideas about highlocalized collective excitations in nuclei of the giant resonance type. The giant dipole E1-resonance (GR) is the main feature in γ-quantum absorption cross-sections of nuclei. The presence of isotopes with multiple isotopes makes it possible to trace the evolution of GR characteristics from changes in the number of neutrons in the nuclei. One such element is tellurium. Purpose. The purpose of this research is an experimental and theoretical study of the cross-section of 122Te(γ, n)121Te reaction in the region of giant E1-resonance energies. Methods. The study of the cross-section of (γ, n) reaction on 122Te isotope was performed on the bremsstrahlung γ-beam of the M-30 microtron of the Institute of Electronic Physics of the National Academy of Sciences of Ukraine. The yield curves were measured in the range of maximum gamma-quantum energies Eγmax=10-18 MeV. The reaction cross-section was calculated by the inverse matrix method. When registering the reaction products, an activation technique was used, while the gamma activity of the products was recorded by the spectrometric method. The theoretical calculations of the cross-section for the 122Te(γ, n)121Te reaction were performed using the TALYS-1.9 software package. Results. The measured experimental yield ratios of the 122Te(γ, n)121Te і 130Te(γ, n)129Te d= Yn121 /Yn129 = f (E max) reactions allowed the experimental cross-section for the 122Te(γ, n)121Te reaction to be calculated. The cross-section has a single hump shape with a maximum at an energy of ~ 15.3 MeV. It was approximated by the Lorentz curve with the parameters δ0 =(274.1±2.1) MB, Е0 (15.27±0.10) MeV, Г0 =(4.76±0.08) MeV. The cross-section obtained was compared with similar cross-sections for 126Te and 130Te isotopes, as well as with theoretical calculations according to the TALYS-1.9 program. Conclusions. The obtained cross-section for the 122Te(γ, n)121Te reaction is consistent with the evolution of the parameters of (γ, n) reaction cross-section on tellurium isotopes 130Te(γ, n)129Te with a change in the number of neutrons. The theoretical approaches used are satisfactorily consistent with the experimental data. This agreement indicates the main contribution of the statistical mechanism to the cross-section of the considered (γ, n) reaction and a relatively small contribution of semi-direct processes