Speaker
Description
Full angular distributions for the elastic scattering of the $^9$Be + $^{80}$Se system were measured at eleven bombarding energies around the Coulomb barrier namely, 17,18, 19, 20, 21, 22, 23, 24, 25, 30 and 32.8 MeV, in order to investigate the influence of the breakup of the weakly bound $^9$Be projectile on the reaction mechanisms. The $^9$Be beams were delivered by the 20 UD tandem accelerator of the TANDAR Laboratory at Buenos Aires. The experimental data have been analyzed in the framework of the optical model using two different potentials: 1) a semi-microscopic double folding potential with normalization factors for the real and imaginary parts, $N_R$ and $N_I$ respectively, as free parameters, and 2) a phenomenological Wood-Saxon potential with six free parameters, namely the depth, radius parameter and diffusivity for the real part ($V$, $r_{0R}$ and $a_R$) and the similarly for the imaginary part ($W$, $r_{0I}$ and $a_I$). The coupling to the breakup channel, at energies close and below the Coulomb barrier, is reflected as an increase of the imaginary part of the potential as a function of the decreasing bombarding energies, while the real part decreases in strength. The correlation is explained by the dispersion relation, which connects the real and imaginary parts of the nuclear potential. The analysis of the the present experimental data shows that the energy dependence of the two parts of the optical potential indeed presents a behavior consistent with the so called Breakup Threshold Anomaly (BTA). The uncertainties in the study of the parameter´s dependence with energy are studied using the covariance-matrix method [2]. As a conclusion, we will show that the BTA is determined unambiguously, independently of the model chosen for the nuclear potential.
- M. Hussein, et al. Physical Review C76, 019902(E) (2007)
- D. Abriola, G. V. Marti and J. E. Testoni, International Conference on Nuclear Data for Science and Technology (ND 2016), September 11-16, 2016
