Experimental estimates on radiative strength function of low-energy γ-quanta following even-odd heavy nuclei decay

The applicability of the method of summed amplitudes of coinciding pulses to determine radiative strength functions of heavy nuclei by measuring two-step cascade γ-ray spectra is discussed. Experiments based on thermal neutron capture in 136Ba and 180Hf were carried out to test this method. The values obtained for the radiative strength functions of a wide region of primary transitions were compared with the predictions of two modifications of the giant-dipole resonance model. Some insight into the characteristics of the γ-decay of compund states is provided by analyzing the information obtained on the two-step γ-decay of a number of nuclei in the mass region 137≤A≤187. 42 refs.; 5 figs.; 1 tab