Multinucleon transfer reactions for theSi28+Zr90,94systems in the region below and near the Coulomb barrier

Abstract

Measurements on multinucleon transfer reactions for $^{28}\mathrm{Si}+^{90,94}\mathrm{Zr}$ systems were performed at sub- and near-barrier energies. The fact that $^{90}\mathrm{Zr}$ has a closed neutron shell ($N$ $=$ 50) and $^{94}\mathrm{Zr}$ has four neutrons outside the closed shell, allows us to investigate the effects of shell closure and pairing correlation on multinucleon transfer mechanism. The experiment was performed with pulsed $^{28}\mathrm{Si}$ beam using the Heavy Ion Reaction Analyzer (HIRA) at Inter University Accelerator Centre (IUAC), New Delhi. Based on the $Q$-value considerations, it turned out that pickup channels were neutron transfer whereas stripping channels were proton transfer. For the $^{28}\mathrm{Si}+^{90}\mathrm{Zr}$ system, the values of the slope parameter for two-neutron pickup turned out to be less than that for one-neutron pickup. The values of the slope parameter were almost the same for two-, three-, and four-neutron pickup channels in the case of the $^{28}\mathrm{Si}+^{94}\mathrm{Zr}$ system. The transfer probabilities in the case of the $^{28}\mathrm{Si}+^{94}\mathrm{Zr}$ system were much larger than those for the $^{28}\mathrm{Si}+^{90}\mathrm{Zr}$ system, further supporting the fact that there is a correlation between the transfer channels and sub-barrier fusion cross-section enhancement. An odd-even staggering was observed in the extracted transfer probabilities at the barrier radius implying the role of pairing correlation in transfer reactions.