A global dispersive coupled-channel optical model potential for actinides

Abstract

A global dispersive coupled-channel optical model (DCCOM) potential is proposed to describe neutron and proton interactions with actinide nuclei in the 0.001 to 200MeV range. A linear dependence of the geometrical parameters on the mass number A is employed, and deformation parameters are adjusted for each nucleus to extend the DCCOM determined previously for 238U and 232Th to neighboring nuclei, 237Np, 241Am, 242,240,239Pu, and 235,233U. Fitted deformations are in reasonable agreement with those derived theoretically. The present DCCOM is capable of describing not only the cross sections but also the total cross section differences between 232Th and 238U up to 200 MeV within experimental uncertainty, verifying that the isovector potential and assumed geometrical parameters are adequate for describing the minute difference between the cross sections of actinide nuclei and their energy dependence. The present results are compared with calculations obtained using non-dispersive potentials frequently employed in this mass range to reveal the advantage of employing a dispersion relation. © 2008 Taylor and Francis Group, LLC.