Seventh European summer school on experimental nuclear astrophysics

Elastic scattering of $^{17}$O ions from $^{58}$Ni and $^{208}$Pb at near-barrier energy

Not scheduled

Santa Tecla (CT), Sicily, Italy

Speaker

Emanuele Strano (PD)

Description

Elastic scattering experiments provide a first information on the overall reactivity of an exotic projectile. We have recently undertaken a research program aimed at measuring the $^{17}$O elastic scattering process from different targets, being $^{17}$O (S$_n$ = 4.143 MeV) the mirror nucleus of the weakly-bound and radioactive $^{17}$F (S$_p$ = 0.600 MeV). The experiment was performed at the Laboratori Nazionali di Legnaro with an $^{17}$O beam impinging on a $^{58}$Ni (150 $\mu$g/cm$^2$) target at 2.5-MeV steps from 42.5 to 55 MeV and on a $^{208}$Pb (200 $\mu$g/cm$^2$) target at 5 energies in the interval 78-87 MeV. We used three modules of the EXPADES detector array. Two 300-$\mu$m thick Double Sided silicon Strip Detectors (DSSSDs) were placed symmetrically to the beam axis to cover the angular range $\theta_{lab}$ = [36$^{\circ}$-74$^{\circ}$]. A DSSSD telescope (40+300 $\mu$m) was placed at backward angles to cover the range $\theta_{lab}$ = [95$^{\circ}$-125$^{\circ}$]. The results were analyzed within the framework of the optical model to extract the reaction cross sections. Quite unexpectedly, the reaction cross sections, after being scaled for the different projectile atomic number, result to be larger for the stable well-bound $^{17}$O rather than for the weakly-bound radioactive $^{17}$F. Therefore, we can conclude that for the pair $^{17}$O-$^{17}$F nuclear structure effects play a more crucial role than the projectile binding energy in the reaction dynamics at Coulomb barrier energies.