Study of reactions induced by 6He on 9Be

We present the results of experiments using a 6He beam on a 9Be target at\ud energies 7 − 9 times the Coulomb barrier. Angular distributions of the elastic, inelastic\ud scattering (target breakup) and the -particle production in the 6He+9Be collision have\ud been analysed. Total reaction cross sections were obtained from the elastic scattering\ud analyses and a considerable enhancement has been observed by comparing to stable systems.FAPESPFundação Araucári

The Li-8(p, alpha)He-5 reaction at low energies, and Be-9 spectroscopy around the proton threshold

We present a direct measurement of the low-energy Li-8(p, alpha)He-5 cross section, using a radioactive Li-8 beam impinging on a thick target. With four beam energies, we cover the energy range between E-c.m. = 0.2 and 2.1 MeV. An R-matrix analysis of the data is performed and suggests the existence of two broad overlapping resonances (5/2(+) at E-c.m. = 1.69 MeV and 7/2(+) at E-c.m. = 1.76 MeV). At low energies our data are sensitive to the properties of a subthreshold state (E-x = 16.67 MeV) and of two resonances above threshold. These resonances were observed in previous experiments. The R-matrix fit confirms spin assignments, and provides partial widths. We propose a new Li-8(p, alpha)He-5 reaction rate and briefly discuss its influence in nuclear astrophysics. DOI: 10.1103/PhysRevC.86.064321Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [2003/10099-2, 2004/07379-6, 2008/09341-7]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Comissao de Aperfeicoamento do Ensino Superior (CAPES)Comissao de Aperfeicoamento do Ensino Superior (CAPES

Study of elastic scattering between exotic projectiles and medium target

Radioactive beams of 8Li and 6He were produced using the double superconducting solenoid system of RIBRAS (Radioactive Ion Beams in Brasil) with a primary beam of 7Li of Elab = 30 MeV, at the São Paulo Pelletron Accelerator. The production reactions were 9Be(7Li, 8Li)8Be and 9Be(7Li, 6He)10B. The angular distributions of the elastic scattering of the 8Li radioactive beam of 26.0 MeV and 6He radioactive beam of 23.0 MeV were measured on 51V target of 1.9 mg/cm2.The elastic scattering angular distributions were analyzed using Optical Model, where the real and imaginary parts are described through a Non-Local Interaction Model called São Paulo Potential . The results were compared with the data present in the literature. The largest cross section, particularly for the halo 6He, shows evidence of the importance of the break up for these medium mass systems. [1]R. Lichtenthaler et al, Eur. Phys. J. A 25,s01,733 (2005); [2]L.C. Chamon et al, Phys. Rev. C66 (2002) 014610.Radioactive beams of 8Li and 6He were produced using the double superconducting solenoid system of RIBRAS (Radioactive Ion Beams in Brasil) with a primary beam of 7Li of Elab = 30 MeV, at the São Paulo Pelletron Accelerator. The production reactions were 9Be(7Li, 8Li)8Be and 9Be(7Li, 6He)10B. The angular distributions of the elastic scattering of the 8Li radioactive beam of 26.0 MeV and 6He radioactive beam of 23.0 MeV were measured on 51V target of 1.9 mg/cm2.The elastic scattering angular distributions were analyzed using Optical Model, where the real and imaginary parts are described through a Non-Local Interaction Model called São Paulo Potential . The results were compared with the data present in the literature. The largest cross section, particularly for the halo 6He, shows evidence of the importance of the break up for these medium mass systems. [1]R. Lichtenthaler et al, Eur. Phys. J. A 25,s01,733 (2005); [2]L.C. Chamon et al, Phys. Rev. C66 (2002) 014610

alpha-particle production in (6)He+(120)Sn collisions

The collision (6)He+ (120)Sn has been investigated at four energies near the Coulomb barrier. A large yield of a particles has been detected, with energies around the energy of the scattered (6)He beam. The energy and angular distributions of the a particles have been analyzed and compared with breakup and neutron transfer calculations.Fundacao de Amparoa Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Spanish Ministerio de Educacion y Ciencia[PCI2006-A7-0654]Spanish Ministerio de Ciencia e Innovacion[FPA2006-13807-c02-01]Junta de Andalucia[P07-FQM-02894]Spanish Consolider-Ingenio[CSD2007-00042

Elastic scattering measurements for [sup 7]Be+[sup 27]Al system at RIBRAS facility

Elastic scattering angular distribution measurements of 7Be_27Al system were performed at the laboratory energy of 15.6MeV. The 7Be secondary beam was produced by the proton transfer reaction 3He (6Li, 7Be) and impinged on 27Al and 197Au targets, using the Radioactive Ion Beam (RIB) facility, RIBRAS. The elastic angular distribution was obtained within the angular range of 15° - 80° at the center of mass frame. Optical model calculations have been performed using the Woods- Saxon form factors and the São Paulo potential to fit the experimental data. The total reaction cross section was derived.CNPqFAPER

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

The elastic-scattering angular distribution for (8)Li on (12)C has been measured at E(LAB) = 23.9 MeV with (8)Li 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 Sao 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 (12)C((8)Li, (9)Be)(11)B reaction was also measured at the same energy. The spectroscopic factor for the <(9)Be|(8)Li + 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 (6,7,8)Li isotopes on (12)C was performed as a function of energy.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[2003/10099-2]Fundacao de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ)Conselho Nacional de Pesquisa e Desenvolvimento (CNPq)Projeto de acao complementaria internacional Sevilla-Sao Paulo[PCI2006-A7-0654](CAPES) Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior ( APES

Experimental study of (6)He + (9)Be elastic scattering at low energies

New data for the (6)He + (9)Be reaction at E(1ab) = 16.2 and 21.3 MeV have been taken and analyzed. The effect of the collective couplings to the excited states of the target has been studied by means of coupled-channels calculations, using a double-folding potential for the bare interaction between the colliding nuclei, supplemented with a phenomenological imaginary part of Woods-Saxon type. In addition, three- and four-body continuum-discretized coupled-channels calculations have been performed to investigate the effect of the projectile breakup on the elastic scattering. Both effects, the coupling to target and projectile excited states, are found to affect significantly the elastic scattering. The trivial local polarization potential extracted from the continuum-discretized coupled-channels calculations indicates that continuum couplings produce a repulsive real part and a long-range imaginary part in the projectile-target interaction.Junta de AndaluciaFAPESPBanco SantanderSpanish Ministerio de Ciencia e Innovacion[FPA2009-07653]Spanish Ministerio de Ciencia e Innovacion[PCI2006-A7-0654]Spanish Consolider-Ingenio[CSD2007-00042

(7,9,10)Be elastic scattering and total reaction cross sections on a (12)C target

Elastic scattering angular distributions for (7)Be, (9)Be, and (10)Be isotopes on (12)C target were measured at laboratory energies of 18.8, 26.0, and 23.2 MeV, respectively. The analysis was performed in terms of optical model potentials using Woods-Saxon and double-folding form factors. Also, continuum discretized coupled-channels calculations were performed for (7)Be and (9)Be + (12)C systems to infer the role of breakup in the elastic scattering. For the (10)Be + (12)C system, bound states coupled-channels calculations were considered. Moreover, total reaction cross sections were deduced from the elastic scattering analysis and compared with published data on other weakly and tightly bound projectiles elastically scattered on the (12)C target, as a function of energy.Conselho Nacional de Pesquisa e Desenvolvimento (CNPq)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP

Total reaction cross-sections for light weakly bound systems

We have measured the elastic scattering cross-section for (8)Li + (9)Be and (8)Li + (51)V systems at 19.6 MeV and 18.5 MeV, respectively. We have also extracted total reaction cross sections from the elastic scattering analysis for several light weakly bound systems using the optical model with Woods-Saxon and double-folding-type potentials. Different reduction methods for the total reaction cross-sections have been applied to analyze and compare simultaneously all the systems.CNPqConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESPFAPERJFundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)DAE-BRNS (Mumbai)Department of Atomic Energy of India (DAE)IUAC-UGC (New Delhi)IUAC-UGC (New Delhi)The World Academy of Sciences (TWAS) for the advancement of science in developing countriesTWAS-ICTP, ItalyConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq, BrazilUGCUGCPhysics Department, MSUPhysics Department, MSUIndia Council for Scientific and Industrial Research (CSIR)CSIR, New Delh