Ordenamento do Território e Planeamento Ambiental : investigação e prática

A secção Biologia é coordenada pelo Professor Universitário Armindo Rodrigues.O CIGPT fundado pelos Geógrafos Helena Calado e João Porteiro desenvolveu nas duas últimas décadas um esforço considerável na investigação e prática do Ordenamento Territoria

Role of Coulomb and nuclear breakups in the interaction of B-8 with C-12

We investigate the breakup of the proton halo B-8 projectile in the presence of the light target C-12 at near barrier energies. Our calculations show that the effect of the breakup on the elastic scattering angular distributions is negligible. We also investigate the relative importance of Coulomb and nuclear breakups for this system. We compare the results of our calculations with those for the He-6 + C-12 and B-8 Ni-58 systems. (C) 2012 Elsevier B.V. All rights reserved.CNPqCNPqFAPERJFAPERJCAPESCAPESPronexPRONE

An imaginary potential with universal normalization for dissipative processes in heavy-ion reactions

In this work we present new coupled channel calculations with the Sao Paulo potential (SPP) as the bare interaction, and an imaginary potential with system and energy independent normalization that has been developed to take into account dissipative processes in heavy-ion reactions. This imaginary potential is based on high-energy nucleon interaction in nuclear medium. Our theoretical predictions for energies up to approximate to 100 MeV/nucleon agree very well with the experimental data for the p, n + nucleus, (16)O + (27)Al, (16)O + (60)Ni, (58)Ni + (124)Sn, and weakly bound projectile (7)Li + (120)Sn systems. (C) 2008 Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), BrazilConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

X-ray spectrometry: a powerful tool for the measurement of complete fusion of weakly bound nuclei

We describe how the method of detection of delayed K x-rays produced by the electron capture decay of the residual nuclei can be a powerful tool in the investigation of the effect of the breakup process on the complete fusion (CF) cross-section of weakly bound nuclei at energies close to the Coulomb barrier. This is presently one of the most interesting subjects under investigation in the field of low-energy nuclear reactions, and the difficult experimental task of separating CF from the incomplete fusion (ICF) of one of the breakup fragments can be achieved by the x-ray spectrometry method. We present results for the fusion of the (9)Be + (144)Sm system. Copyright (c) 2008 John Wiley & Sons, Ltd.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPqFundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)FAPERJCAPESCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESPConsejo Nacional de Investigaciones Científicas y Técnicas de Argentina (CONICET)CONICE

Near-barrier quasielastic scattering as a sensitive tool to derive nuclear matter diffuseness

Quasielastic excitation functions for the (16,18)O + (60)Ni systems were measured at energies near and below the Coulomb barrier, at the backward angle theta(LAB) = 161 degrees. The corresponding quasielastic barrier distributions were derived. The data were compared with predictions from coupled channel calculations using a double-folding potential as a bare potential. For the (16)O-induced scattering, good agreement was obtained for the barrier distribution by using the projectile default nuclear matter diffuseness obtained from the Sao Paulo potential systematic, that is, 0.56 fm. However, for the (18)O-induced scattering, good agreement was obtained only when the projectile nuclear matter diffuseness was changed to 0.62 fm. Therefore, in this paper we show how near-barrier quasielastic scattering can be used as a sensitive tool to derive nuclear matter diffuseness.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ)Fundacao de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

Challenging measurement of the (16)O+(27)Al elastic and inelastic angular distributions up to large angles

The (16)O+(27)Al elastic and inelastic angular distributions have been measured in a broad angular range (13 degrees < theta(lab) < 52 degrees) at about 100 MeV incident energy. The use of the MAGNEX large acceptance magnetic spectrometer and of the ray-reconstruction analysis technique has been crucial in order to provide, in the same experiment, high-resolution energy spectra and cross-section measurements distributed over more than seven orders of magnitude down to hundreds of nb/sr. (C) 2011 Elsevier B.V. All rights reserved

Nuclear rainbow in the O-16+(27)AL system: The role of couplings at energies far above the barrier

High precision elastic and inelastic angular distributions have been measured for the O-16 + Al-27 system at a beam energy of 100 MeV. The data analysis confirms a rainbow formation as already predicted by parameter-free Coupled Channel calculations. It also helps to reveal the crucial role of inelastic couplings in the rainbow formation for heavier systems even at energies far above the Coulomb barrier. This feature, well known in atomic/molecular scattering, is experimentally studied for the first time in Nuclear Physics. (C) 2012 Elsevier B.V. All rights reserved.Istituto Nazionale di Fisica Nucleare (INFN)Istituto Nazionale di Fisica Nucleare (INFN)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Fundacao de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ)Fundacao de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

Elastic scattering and total reaction cross sections for the (8)B, (7)Be, and (6)Li+(12)C systems

Angular distributions for the elastic scattering of (8)B, (7)Be, and (6)Li on a (12)C target have been measured at E(lab) = 25.8, 18.8, and 12.3 MeV, respectively. The analyses of these angular distributions have been performed in terms of the optical model using Woods-Saxon and double-folding type potentials. The effect of breakup in the elastic scattering of (8)B + (12)C is investigated by performing coupled-channels calculations with the continuum discretized coupled-channel method and cluster-model folding potentials. Total reaction cross sections were deduced from the elastic-scattering analysis and compared with published data on elastic scattering of other weakly and tightly bound projectiles on (12)C, as a function of energy. With the exception of (4)He and (16)O, the data can be described using a universal function for the reduced cross sections.Conselho Nacional de Pesquisa e Desenvolvimento (CNPq)Conselho Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)National Science Foundation NSF[PHY-0652591]National Science Foundation NSF[PHY-0969456]CONACYT (Mexico

Probing the (6,7)Li nucleon densities through a new break-up process approach

In this work we present a double folding optical model analysis of new near-barrier quasi-elastic experimental data for the (6,7)Li + (120)Sn systems. From the analysis, it was possible to confirm the ground-state nucleon densities assumed for the weakly bound (6,7)Li isotopes. The apparent discrepancies between the experimental densities and those based on Dirac-Hartree-Fock Bogoliubov (DHB) calculations were removed. A new approach that simulates the projectile break-up and a positive polarization from couplings of (6,7)Li bound states with the continuum was considered in the reaction mechanism. (C) 2010 Elsevier B.V. All rights reserved.FAPESP, BrazilFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq, Brazi