Fission: A filter for the study of nuclear reaction mechanisms

Abstract

The use of nuclear fission as a reaction filter to study the dynamics of low-to-intermediate energy nucleus-nucleus collisions has been widely exploited over the past decade. In particular, the fission fragment angular correlation (folding-angle) technique has been utilized to derive an understanding of linear momentum and energy transfer in projectile-nucleus interactions. These results illustrate the systematic evolution in reaction mechanisms from relatively simple processes such as complete fusion and peripheral transfer reactions at near-barrier bombarding energies to highly complex interactions dominated by precompound processes at intermediate energies. Studies of light charged particles, neutrons and complex fragments in coincidence with fission-tagged events demonstrate the growing influence of nucleon-nucleon collision mechanisms relative to the dinuclear mean field in determining the reaction dynamics with increasing projectile energy. The application of these same techniques to the investigation of the inverse fission process--damped collisions--has also yielded important new insights into this class of reactions and recent results for nuclide distributions and excitation energy sharing are described.