Comparison of 120Sn(6He,6He)120Sn and 120Sn(alpha,alpha)120Sn elastic scattering and signatures of the 6He neutron halo in the optical potential

Cross sections of $^{120}$Sn($\alpha$,$\alpha$)$^{120}$Sn elastic scattering have been extracted from the $\alpha$ particle beam contamination of a recent $^{120}$Sn($^6$He,$^6$He)$^{120}$Sn experiment. Both reactions are analyzed using systematic double folding potentials in the real part and smoothly varying Woods-Saxon potentials in the imaginary part. The potential extracted from the $^{120}$Sn($^6$He,$^6$He)$^{120}$Sn data may be used as the basis for the construction of a simple global $^6$He optical potential. The comparison of the $^6$He and $\alpha$ data shows that the halo nature of the $^6$He nucleus leads to a clear signature in the reflexion coefficients $\eta_L$: the relevant angular momenta $L$ with $\eta_L \gg 0$ and $\eta_L \ll 1$ are shifted to larger $L$ with a broader distribution. This signature is not present in the $\alpha$ scattering data and can thus be used as a new criterion for the definition of a halo nucleus.Comment: 13 pages, 7 figures, accepted for publication in Phys. Rev.

Higher order effects in the 16O(d,p)17O^{16}O(d,p)^{17}O and 16O(d,n)17F^{16}O(d,n)^{17}F transfer reactions

Full Coupled Channels Calculations were performed for the $^{16}O(d,n)^{17}F$ and $^{16}O(d,p)^{17}O$ transfer reactions at several deuteron incident energies from $E_{lab}=2.29$ MeV up to 3.27 MeV. A strong polarization effect between the entrance channel and the transfer channels $^{16}O(d,n)^{17}F(1/2^{+},0.495)$ and $^{16}O(d,p)^{17}O(1/2^{+},0.87)$ was observed. This polarization effect had to be taken into account in order to obtain realistic spectroscopic factors from these reactions.Comment: 15 papes, 13 figures, accepted for publication in Phys. Rev.

The Scientific program with RIBRAS (Radioactive Ion Beams in Brasil)

The Radioactive Ion Beams Facility (RIBRAS) is in operation since 2004 at the Pelletron Accelerator Laboratory of the University of São Paulo and consists of two superconducting solenoids capable of producing low energy secondary beams of light exotic nuclei. Measurements of the elastic scattering, breakup and transfer reactions with radioactive projectiles such as 6He, 8Li, 7Be on several targets have been performed. A review of the research program carried on along the last four years using the RIBRAS facility is presented

Exotic Nuclei in South America

The Radioactive Ion Beams in Brasil (RIBRAS) is described. Experiments using radioactive secondary beams of light rare isotopes such as 6He, 7Be, 8Li on several targets have been performed and the results are presented

The Research Program at RIBRAS (Radioactive Ion Beams in Brasil)-III

A part of the research program developed in the RIBRAS facility over the last four years is presented. Experiments using radioactive secondary beams of light exotic nuclei such as 6He, 7Be, 8Li on several targets have been performed. Elastic angular distributions have been analysed by the Optical Model and four body Continuous Discretized Coupled Channels Calculations (4b-CDCC) and the total reaction cross sections have been obtained. A comparison between the reaction cross sections of 6He and other stable projectiles with medium-heavy targets was performed. Measurements of the proton transfer reaction 12C(8Li,9Be)11B are also presented

Elastic scattering and total reaction cross sections for the 8Li + 12C system

The elastic-scattering angular distribution for 8Li on 12C has been measured at ELAB=23.9 MeV with 8Li radioactive nuclear beam produced by the Radioactive Ion Beams in Brazil facility. This angular distribution was analyzed in terms of optical-model with Woods-Saxon and double-folding São Paulo potential. The roles of the breakup and inelastic channels were also investigated with cluster folding and deformed potentials, respectively, through coupled-channels calculations. The angular distribution for the proton-transfer 12C(8Li,9Be)11B reaction was also measured at the same energy. The spectroscopic factor for the 9Be|8Li+p bound system was obtained and compared with shell-model calculations and with other experimental values. Total reaction cross sections for the present system were also extracted from the elastic-scattering analysis. A systematic of the reduced reaction cross sections obtained from the present and published data on 6,7,8Li isotopes on 12C was performed as a function of energy

α-particle production in 6He + 120Sn collisions

The collision 6He+120Sn has been investigated at four energies near the Coulomb barrier. A large yield of α particles has been detected, with energies around the energy of the scattered 6He beam. The energy and angular distributions of the α particles have been analyzed and compared with breakup and neutron transfer calculations.Ministerio de Ciencia e Innovación (España) FPA2006-13807-c02-01Junta de Andalucía P07-FQM-02894Ministerio de Educación y Ciencia (España) PCI2006-A7-0654Programa Consolider-Ingenio 2010 (España) CSD2007-0004

Measurements of the 25 Mg( 11 B , 12 C) 24 Na and 25 Mg( 11 B , 10 Be) 26 Al proton transfer reactions

Angular distributions for the 11 B+25 Mg elastic scattering, 25 Mg (11B, 12 C) 24 Na proton pickup, and 25 Mg (11 B, 10 Be) 26 Al stripping reactions have been measured at E11 B=35 MeV. The angular distributions have been analyzed by the distorted-waves Born approximation calculations using the code fresco. The spectroscopicfactors for the overlaps 25 Mg | 26 Al , 25 Mg | 24 Na for the ground state and excited states of 26 Al and 24 Na have been obtained and compared to previous measurements and shell-model calculations.FAPESP 01/06676-