Examination of break-up fusion in the O16+Nd148 system through measurements of forward recoil range distributions and angular distributions

Abstract

The forward recoil range distributions and angular distributions of several evaporation residues produced via complete and incomplete fusion (ICF) dynamics in $^{16}\mathrm{O}+^{148}\mathrm{Nd}$ system at energy $\ensuremath{\approx}6$ MeV/nucleon were measured. The measured forward recoil range distributions of various reaction products show the presence of incomplete fusion components apart from complete fusion. Full and partial linear momentum transfer components of reaction products were found in the interaction of $^{16}\mathrm{O}$ with $^{148}\mathrm{Nd}$. These results were also confirmed by the measurements of angular distributions of evaporation residues. The measured angular distributions of the evaporation residues populated through complete and incomplete fusion channels were found to be distinctly different. The evaporation residues populated via complete fusion channels were trapped in the narrow angular zone as compared to incomplete fusion channels. A systematic study of the dependence of incomplete fusion dynamics on well-known entrance channel parameters shows that the incomplete fusion fraction grows exponentially with mass asymmetry $({\ensuremath{\mu}}_{EC}^{AS})$, Coulomb factor $({Z}_{P}{Z}_{T})$ and $\ensuremath{\alpha}\ensuremath{-}Q$ value of the projectile. The present observations suggest an exponential rise of ICF fraction with entrance channel parameters in contrast with the linear pattern reported in some earlier measurements. Further, the correlation of incomplete fusion fraction with the structure of target (T) was investigated employing four different parameters viz. deformation parameter $({\ensuremath{\beta}}_{2}^{T})$, interaction radius $({R}^{T})$, deformation length $({\ensuremath{\beta}}_{2}^{T}{R}^{T})$ and excess of neutrons ${(N\ensuremath{-}Z)}^{T}$ in the target. In the present study, the ICF fraction was found to rise exponentially with these parameters, independently for different projectiles. The three parameters ${\ensuremath{\beta}}_{2}^{T}, {\ensuremath{\beta}}_{2}^{T}{R}^{T}$, and ${(N\ensuremath{-}Z)}^{T}$ were found more sensitive and effective to investigate the entire picture about the influence of projectile and target deformation along with their relative orientations on incomplete fusion dynamics at low projectile energy. Moreover, the interaction radius of target $({R}^{T})$ is suitable to explain the characteristics of ICF dynamics in the spherical-spherical collisions. These present results show that incomplete fusion dynamics is strongly affected by the structure of projectile along with the target.