Isomeric ratios in the reactions induced by γ-rays and fast neutrons on the isotopes of Re, Ir and Au

The isomeric ratios in the reactions (γ, n) and (n, 2n) leading to the production of odd-odd nuclides 184Re, 190Ir, and 196Au are measured. The measurements were performed by the activation method at the irradiation of natural Re, Ir, and Au samples by 14.7-MeV neutrons and by the bremsstrahlung with a boundary energy of 22 MeV. Identification of the obtained nuclei in isomeric and ground states was made basing on their spectra of X or γ radiation and on the half-life. A calculation of the isomeric ratios was performed on the basis of the statistical model, and the parameters describing the dependence of the level density on the excitation energy and angular momentum were determined from the comparison of experimental and calculated values. The influence of the nuclear structure on these parameters is discussed