Investigation of the role of neutron transfer in the fusion of 32,34S with 197Au, 208Pb using quasi-elastic scattering

Abstract

Excitation functions for quasi-elastic scattering have been measured at backward angles for the systems 32,34 S + 197 Au and 32,34 S + 208 Pb for energies spanning the Coulomb barrier. Representative distributions, sensitive to the low energy part of the fusion barrier distribution, have been extracted from the data. For the fusion reactions of 32,34 S with 197 Au couplings related to the nuclear structure of 197 Au appear to be dominant in shaping the low energy part of the barrier distribution. For the system 32 S + 208 Pb the barrier distribution is broader and extends further to lower energies, than in the case of 34 S + 208 Pb. This is consistent with the interpretation that the neutron pick-up channels are energetically more favoured in the 32 S induced reaction and therefore couple more strongly to the relative motion. It may also be due to the increased collectivity of 32 S, when compared with 34 S.

Probing surface diffuseness of nucleus-nucleus potential with quasielastic scattering at deep sub-barrier energies

“…We apply this procedure to the 32,34 S + 208 Pb, 32,34 S + 197 Au [14], and 16 O + 208 Pb [15] reactions which involve spherical nuclei, as well as the 16 O + 154 Sm and 16 O + 186 W reactions [16] which involve a deformed target. For the deformed systems the scarcity of data points at deep sub-barrier energies led us to extend the fitting region to somewhat higher energies.…”

“…Figure 2 The experimental data are taken from Ref. [14]. The solid line results from using a diffuseness parameter obtained by performing a least-square fit to the data.…”

“…2:The ratio of the quasielastic to the Rutherford cross sections for the 32 S + 208 Pb (the upper panel) reaction at θ lab = 170 • and for the 34 S + 208 Pb (the lower panel) reaction at θ lab = 159 • . The experimental data are taken from Ref [14]…”

Probing fusion dynamics with scattering experiments

“…The sensitivity of the representation D qel (E) to the fusion barrier distribution at energies below the average fusion barrier has been confirmed by experiments for a variety of systems with widely different fusion dynamics and coupling interactions [9,10,11,12,13,14,15]. It has, however, also become clear that at energies above the average fusion barrier the representation D qel (E) rapidly looses this sensitivity with increasing energy.…”