Mass and charge distributions in Fe-induced reactions.

Abstract

The charge and mass of the projectilelike fragments produced in the 12-MeV/nucleon $^{56}\mathrm{Fe}$${+}^{165}$Ho reaction were measured at a laboratory scattering angle of 16\ifmmode^\circ\else\textdegree\fi{}. The mass and charge distributions of the projectilelike fragments were generated as a function of total kinetic energy loss (TKEL), and characterized by their neutron and proton centroids and variances, and correlation factors. A weak drift of the system towards mass asymmetry, opposite to the direction which minimizes the potential energy of the composite system, was observed. The increase in the variances with energy loss is consistent with a nucleon exchange mechanism as a means for energy dissipation. Predictions of two nucleon exchange models, Randrup's and Tassan-Got's models, are compared to the experimental results of the 672-MeV $^{56}\mathrm{Fe}$${+}^{165}$Ho reaction and to other Fe-induced reactions. The proton and neutron centroids were found to be generally better reproduced by Tassan-Got's model than by Randrup's model. The variances and correlation factor are well reproduced for asymmetric systems by both models.