Evaporation residues at E∗≈400 MeV ☆

Abstract For the reaction 11.4 MeV/u 86 Kr+ 104 Ru, which leads to the compound nucleus 190 Hg ∗ at an excitation energy of 396 MeV, we have measured a total evaporation-residue yield of 25±3 mb. As a pure Bohr-Wheeler fission-evaporation calculation for this system predicts σ ER −4 mb, we postulate that the highly-excited compound nuclei here decay initially by particle emission only, due to dynamic hindrance of the fission process, thereby enhancing the evaporation-residue yield for this system by over five orders of magnitude.