The entrance-channel dependence of the distribution of reaction strength has been studied for three systems, namely ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$${+}^{182}$W, ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ti}$${+}^{166}$Er, and ${}_{}{}^{60}{}_{}{}^{}\mathrm{Ni}$${+}^{154}$Sm, which all lead to the compound system ${}_{}{}^{214}{}_{}{}^{}\mathrm{Th}$ in complete fusion reactions. The cross sections for elastic/quasielastic scattering, deeply inelastic, and fissionlike processes were measured at beam energies of ${\mathit{E}}_{\mathrm{lab}}$ =166, 177, 222, 260 MeV for ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$${+}^{182}$W, ${\mathit{E}}_{\mathrm{lab}}$=220, 240, 270, 298 MeV for ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ti}$${+}^{166}$Er, and ${\mathit{E}}_{\mathrm{lab}}$=339, 390, 421 MeV for ${}_{}{}^{60}{}_{}{}^{}\mathrm{Ni}$${+}^{154}$Sm, respectively. The maximum contribution of complete-fusion fission processes to the fissionlike cross section is estimated on the basis of expected angle-mass correlations for such reactions. The results show a strong entrance-channel dependence as predicted by the extra-push model. © 1996 The American Physical Society.

• Received 25 October 1995

DOI:https://doi.org/10.1103/PhysRevC.53.1734