Observation of entrance channel effects in compound nucleus formation with high energy gamma-rays

摘要

We investigated entrance channel effects in the decay of excited (sup 160)Er and (sup 164)Yb, formed with (sup 16)O and (sup 64)Ni beams by measuring high energy (5--25 MeV) (gamma)-ray spectra. Gamma rays from the decay of the giant dipole resonance (GDR) built on highly excited states provide a good probe to study these effects, since the (gamma) rays are emitted in the early stages of the reaction. The (gamma)-ray spectra measured in the (sup 16)O-induced reactions show the typical GDR bump whereas the (gamma)-ray spectra from the more symmetric entrance channels show dramatically different shape. 22 refs., 5 figs., 2 tabs. (ERA citation 15:036417)