Incomplete fusion in 16O+159Tb

Abstract

In heavy-ion induced reactions, incomplete fusion (ICF) has been found to be a process of greater importance and of distinct nature even at slightly above the barrier energies where complete fusion (CF) is supposed to be dominant. However, the studies are limited to a few projectile target combinations only. To confirm the distinctly different decay patterns observed in case of CF and ICF residues, and to understand the role of high ℓ-values in the onset of ICF, a particle-γ -coincidence technique has been employed to measure spin-distributions and feeding intensity profiles of CF and ICF residues populated via xn/pxn/αxnxn/pxn/αxn-channels in 16O+159Tb interactions at Elab≈83.5±1.5Elab≈83.5±1.5, 88.5±1.588.5±1.5, 93.5±1.593.5±1.5 and 97.6±1.4 MeV97.6±1.4 MeV. The Gamma Detector Array and the Charged Particles Detector Array have been used to detect prompt γ-rays in coincidence with charged particles (p and α). CF-α and ICF-α channels have been identified from backward (B)- and forward (F)-α-gated-γ-spectra, respectively. Reaction dependent decay patterns (thus, the feeding intensity profiles) have been observed in different α emitting channels. The CF channels are found to be widely populated and strongly fed over a broad spin range. In case of ICF-α channels, narrow range feeding was observed only for high-spin states or the low spin states were not populated. The mean ℓ -values involved in the production of ICF-αxnαxn-channels are found to be higher than those involved in the production of CF-αxnαxn-channels associated with fusion-evaporation reactions.