Statistical model calculations of continuum feeding times in heavy-ion fusion reactions

The time development of oxygen-induced compound reactions on ²⁷Al and ⁵⁸Ni targets at 30–70 MeV beam energy has been calculated in the framework of the statistical model. Feeding times associated with the population of yrast states in the evaporation residues have been estimated. It is shown that the experimental feeding times τ₁ < 0.2 ps, when combined with measured evaporation residue cross sections and/or absolute γ-ray yields, put restrictions on the spin dependence of the level density. Furthermore, it has been found that the dipole strength of continuum transitions between high-spin states is of the same order of magnitude as that obtained in radiative neutron capture reactions.