Radiative strength function determination in the (n, 2γ) reaction for soft primary transition in heavy nuclei

The method of amplitude summation of coinciding pulses (SACP) allows one to observe up to 80 % of the total primary transition intensity over a wide range of excitation energies and to extent gamma-decay schemes of heavy nuclei up to 0.5 Bn (where Bn is neutron binding energy). On the base of these investigations the properties of nuclei at excitation energies intermediate between the low-lying simple structure states and the extremely complicated compound states can be studied. In the case of the even-odd nuclei with a large Γ0n values of compound states it is possible to find out lower estimation of radiative strength function for a broad spectrum of primary transition. Radiative strength function of those nuclei could be considered as a superposition of two components -single-particle transitions between 4s and 3p neutron states and statistical nature transitions in accordance to the giant electric dipole resonance GEDR model predictions. Experiments based on neutron capture in 137Ba and 181Hf are performed in order to examine this method. 8 figs., 1 tab., 12 refs. (author)