The study of isomeric ratios in photonuclear reactions forming high spin isomers in the giant dipole resonance region

We studied the isomeric rations in odd nuclei ¹⁹⁶ Au, ¹⁸²Ta and ¹⁹⁴Ir with high spin isomeric states produced in ¹⁹⁷ Au(γ, n)^196m'gAu, ¹⁸³W(γ, p)^182m'gTa and ¹⁸⁵Pt(γ,p)^194m'gIr reactions by using the activation technique and γ-ray spectroscopic method in the giant dipole resonance (GDR) region. The high-purity natural Au, W and Pt foils in disc shape were irradiated with Bremsstrahlung generated from an electron accelerator Microtron. The irradiated foils were measured by the high resolution γ-ray spectroscopic system which consists of a Ge(HP) detector and a multichannel analyzer. In order to improve the accuracy of the experimental results, necessary corrections were made in the γ-ray activity measurements and data analysis. The results were analyzed, discussed and compared with those of other authors as well as with theoretical model calculation. The study shows that the isomeric ratios in nuclei with high spin isomeric states are much lower than that in low spin isomeric state isomers. (author)