Critical asymmetry and the systematics of fission-like processes in the reactions ofC12projectiles with medium mass nuclei

Abstract

The systematics of fission-like processes observed in reactions induced by 107- and 197-MeV ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ projectiles have been investigated. Counter telescopes were employed to detect and identify the products of reactions with ${}_{}{}^{89}{}_{}{}^{}\mathrm{Y}$, ${}_{}{}^{98}{}_{}{}^{}\mathrm{Mo}$, Ag, and ${}_{}{}^{116}{}_{}{}^{}\mathrm{Sn}$. Limited experiments using Ni and Au targets were also performed. For the medium mass targets, cross sections, energy distributions, and angular distribution of the reaction products are reported. Limiting angular momenta for the fusion of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ with Y, Mo, and Ag have been determined and are used to estimate the angular momenta of the collisions leading to fission-like reactions. The probability of occurrence of such reactions is compared with predictions based upon the concept of an angular momentum dependent critical asymmetry. This concept is found to be very useful in discussing the reaction mechanisms involved.