Investigation of Excitation of K Isomers Hf-179m2 and Hf-180m in (gamma, gamma ') Reactions

摘要

The weighted-average cross sections for Hf-179m2 and Hf-180m population in (gamma, gamma') reactions induced by gamma rays of bremsstrahlung spectrum with endpoint energies of 17.5, 37, and 55 MeV were measured for the first time. A second maximum in the excitation function for the K forbidden isomers of Hf-179 and Hf-180 was found in the energy range between 20 and 35 MeV. A respective simulation was performed within the model of pre-equilibrium processes and within the statistical model by employing the TALYS-1.9 and EMPIRE-3.2 codes. It is shown that the integrated cross sections for (gamma, gamma') reactions in the energy range between 20 and 55 MeV are described in the statistical limit of the compound-nucleus volume (TALYS-1.9 code).