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A non-destructive standard-free analytical method of obtaining stable isotope ratios in materials using nuclear reactions excited by an 11.75 MeV proton beam is demonstrated for a special 63Cu/65Cu target characterized traceably by Rutherford backscattering spectrometry (using 2.2 MeV protons). The method is general and is capable of being a useful alternative to standard ICP-MS methods. Relatively high energy proton beams are required to excite multiple isotopes of most elements of interest, and the many resulting nuclear reaction products are filtered by coincidence methods to characterize the desired isotope ratios. Specifically: the use of particle–gamma coincidences permits identification of specific channels populated in the nuclear reaction and avoids or minimizes typical drawbacks of this method including high backgrounds and interfering reactions. The test Cu target was a sandwich of a natural Cu and an enriched 65Cu foil, and particle–gamma coincidences were measured for the reactions 63Cu(p,πγ){63Cu,60Ni} and the corresponding reactions for 65Cu (where “π” represents the energetic charged particle reaction product: proton or alpha). Limitations of the method, and applications in cultural heritage and other fields are discussed.

The $^{8}\mathrm{Li}+^{58}\mathrm{Ni}$ collision is investigated at 23.9, 26.1, 28.7, and 30 MeV bombarding energies. Quasielastic angular distributions and the singles $^{7}\mathrm{Li}$ angular and energy distributions are presented. Coupled-reaction channels (CRC) calculations, which include the coupling of the elastic channel to $^{59}\mathrm{Ni}=^{58}\mathrm{Ni}\phantom{\rule{0.16em}{0ex}}+\phantom{\rule{0.16em}{0ex}}n$ states above and below the neutron threshold, provide a simultaneous description of the quasielastic and transfer distributions and evidence the strong effect of the one-neutron transfer/breakup channels on the quasielastic scattering. The $^{7}\mathrm{Li}$ angular and energy distributions have been also successfully analyzed combining the continuum discretized coupled channels (CDCC) method, for the elastic breakup, and the IAV model of Ichimura, Austern, and Vincent [Phys. Rev. C 32, 431 (1985)], for the nonelastic breakup. These calculations indicate that most of the $^{7}\mathrm{Li}$ yields are due to nonelastic breakup contributions (transfer), whereas elastic breakup plays a minor role.

Background: Reactions involving exotic and stable weakly bound nuclei have been extensively studied in recent years. Although several models have been successfully used to explain particular reaction outcomes, the answers to many questions remain elusive. In previous works, we presented elastic, inelastic, and transfer angular distributions for the $^{10}\mathrm{B}+^{120}\mathrm{Sn}$ system measured at ${E}_{\mathrm{Lab}}=31.5$, 33.0, 35.0, and 37.5 MeV. The data set was analyzed through coupled reaction channels calculations in the context of the double-folding S\~ao Paulo potential.Purpose: We investigate nuclear reaction mechanisms for systems involving weakly bound projectiles.Method: Angular distributions for several nuclear reaction processes were measured for the $^{10}\mathrm{B}+^{120}\mathrm{Sn}$ system at ${E}_{\mathrm{Lab}}=39.70$ MeV.Results: The new data set involves angular distributions for elastic scattering, projectile and target inelastic excitations, one-neutron pickup transfer, one-proton stripping transfer, deuteron pickup transfer, and $^{3,4}\mathrm{He}$ stripping transfer. We have also observed $^{10}\mathrm{Be}$ nuclei. The effect of the couplings to some nonelastic states on the angular distributions is discussed.Conclusion: The theoretical calculations within the coupled reaction channels formalism provide an overall good agreement with the corresponding inelastic, one-neutron stripping, one-proton pickup, one-deuteron pickup, and $^{3}\mathrm{He}$ stripping transfer data. However, to improve the description of the elastic scattering angular distribution, the inclusion of additional channels in the coupling scheme might be necessary.

This work describes the new facility for applied nuclear physics at the University of Sao Paulo, mainly for irradiation of electronic devices. It is a setup composed of a quadrupole doublet for beam focusing/defocusing plus multiple scattering through gold foils to produce low intensity, large-area, and high-uniformity heavy-ion beams from 1H to 107Ag. Beam intensities can be easily adjusted from 102 particles cm2/s to hundreds of nA for an area as large as 2.0 cm2 and uniformity better than 90%. Its irradiation chamber has a high-precision motorized stage, and the system is controlled by a LabViewTM environment, allowing measurement automation. Design considerations and examples of use are presented Este trabalho descreve as novas instalações de física nuclear aplicada da Universidade de São Paulo, principalmente para irradiação de dispositivos eletrônicos. É uma configuração composta por um quadrupolo dupleto para foco / desfoque de feixe mais espalhamento múltiplo através de folhas de ouro para produzir feixes de íons pesados ​​de baixa intensidade, grande área e alta uniformidade de 1 H a 107 Ag. As intensidades do feixe podem ser facilmente ajustadas de 10 2 partículas cm 2 / s a ​​centenas de nA para uma área tão grande quanto 2,0 cm 2 e uniformidade melhor que 90%. Sua câmara de irradiação possui estágio motorizado de alta precisão, e o sistema é controlado por um LabView TMambiente, permitindo a automação da medição. São apresentadas considerações de design e exemplos de uso. 91 5 053301

The $^{10}\mathrm{B}+^{197}\mathrm{Au}$ reaction has been investigated through cross-section measurements for different channels, such as quasielastic and elastic scattering, inelastic excitation of low-lying $^{197}\mathrm{Au}$ states, and one-neutron pickup and one-proton stripping transfer reactions. Experimental angular distributions were obtained for 20 bombardment energies around the Coulomb barrier: $38\ensuremath{\le}{E}_{lab}\ensuremath{\le}61\phantom{\rule{0.16em}{0ex}}\mathrm{MeV}$. Coupled reaction channels calculations have been performed in the context of the double-folding S\~ao Paulo potential, and details of the data analysis are discussed along the paper. In general, the theoretical calculations provide a satisfactory description of the data.

In a previous work, we presented data for the $^{10}\mathrm{B}+^{197}\mathrm{Au}$ system, corresponding to quasielastic and elastic scattering, $^{197}\mathrm{Au}$ inelastic excitation, and one neutron pickup transfer, measuring the angular distribution of scattered beam-like ejectiles at several energies around the Coulomb barrier. In this paper, we present data for the fusion process of the same system, at several energies around the Coulomb barrier, as well as new data for one neutron pickup and stripping transfer. In this case, we detected offline $\ensuremath{\gamma}$ rays stemming from the $\ensuremath{\beta}$-delayed decay chain of fusion-evaporation residues and heavy transfer products. As in our previous work, we analyzed this data set with coupled reaction channels calculations using the S\~ao Paulo potential. We show that the coupling to the one neutron transfer channel is quite important to describe the fusion data at the sub-barrier energy region. We also provide a comparison of the experimental fusion cross sections obtained for $^{10}\mathrm{B}+^{197}\mathrm{Au}$ with data for several other systems involving the same target nucleus.

Background: Neutron transfer measurements for the $^{18}\mathrm{O}+^{28}\mathrm{Si}$ system have shown that the experimental one-neutron and two-neutron transfer cross sections are well reproduced with spectroscopic amplitudes from two different shell-model interactions for the Si isotopes: psdmod for the two-neutron transfer, and psdmwkpn for the one-neutron transfer.Purpose: The need for two distinct shell-model interactions to reproduce two neutron-transfer processes in the same nuclei may cover a more complex mechanism in the one-neutron transfer that requires the unpairing of neutrons prior to its transfer in the ($^{18}\mathrm{O},^{17}\mathrm{O}$) reaction. Studying a nucleus where this characteristic is absent ($^{13}\mathrm{C}$) should help to elucidate this question.Method: One-neutron transfer cross sections were measured for the $^{13}\mathrm{C}+^{28}\mathrm{Si}$ at ${E}_{lab}=30$ and 34 MeV, and compared with coupled reaction channel calculations using spectroscopic amplitudes derived from the psdmod and psdmwkpn shell-model interactions.Results: The spectroscopic amplitudes from the psdmod interaction for the relevant states in $^{29}\mathrm{Si}$ provide a good description of the experimental data and the corresponding values agree with previous estimates obtained from the $(d,p)$ reaction.Conclusions: The experimental data for the one-neutron transfer to $^{28}\mathrm{Si}$ induced by ($^{13}\mathrm{C},^{12}\mathrm{C}$) reaction is well reproduced using spectroscopic amplitudes from the psdmod.

Alpha particle energy distributions in the 6He+120Sn collision have been measured at 7 bombarding energies above the Coulomb barrier. A phenomenological analysis of the centroids of the experimental distributions was performed and compared with the expected alpha-particle energies from breakup and neutron transfer reactions. Q-optimum conditions were determined using the Brinks formula for the di-neutron transfer reaction. A comparison of the measured alpha-particle production cross-sections with Continuum Discretized Coupled Channels (CDCC) calculations for breakup is presented. Fundacao de Amparo `a Pesquisa no Estado de Sao Paulo 2013/22100-7, 2014/19666-1 Conselho Nacional de Desenvolvimento Cientıfico e Tecnologico 308935/2018-7 Ministerio de Economía y Competitividad FIS2017-88410-P European Union 654002

We present new experimental angular distributions for the elastic scattering of $^{6}\mathrm{Li}+^{120}\mathrm{Sn}$ at three bombarding energies. We include these data in a wide systematic involving the elastic scattering of $^{4,6}\mathrm{He},\phantom{\rule{0.16em}{0ex}}^{7}\mathrm{Li}$, $^{9}\mathrm{Be},\phantom{\rule{0.16em}{0ex}}^{10}\mathrm{B}$, and $^{16,18}\mathrm{O}$ projectiles on the same target at energies around the respective Coulomb barriers. Considering this data set, we report on optical model analyses based on the double-folding S\~ao Paulo potential. Within this approach, we study the sensitivity of the data fit to different models for the nuclear matter densities and to variations in the optical potential strengths.

The elastic scattering of the radioactive proton-rich carbon isotope $^{10}\mathrm{C}$ has been investigated. A full differential angular distribution for the elastic scattering of $^{10}\mathrm{C}$ on a $^{58}\mathrm{Ni}$ target has been measured at ${E}_{\mathrm{Lab}}=35.3$ MeV, which is just above the Coulomb barrier for this system (${V}_{B}=27$ MeV). The obtained angular distribution was analyzed in terms of coupled-channels, coupled-reaction-channels, and continuum-discretized coupled-channels calculations. In the coupled-channels calculation, several inelastic transitions of the target and the first (${2}^{+}$) excited state of the $^{10}\mathrm{C}$ projectile were considered. The coupling to the first (${2}^{+}$) excited state of $^{10}\mathrm{C}$ was shown to be very important to describe the rising of the cross section at backward angles. We also performed an analysis with the continuum-discretized coupled channels, considering the $^{9}\mathrm{B}+p$ and $^{6}\mathrm{Be}+\ensuremath{\alpha}$ channels, which indicated a strong cluster configuration for the $^{10}\mathrm{C}$ projectile.

Elastic scattering and transfer cross sections for the $^{7}\mathrm{Be}+^{9}\mathrm{Be}$ system have been measured at ${E}_{\mathrm{lab}}=23.1\phantom{\rule{0.28em}{0ex}}\mathrm{MeV}$ using the $^{7}\mathrm{Be}$ radioactive secondary beam produced at Radioactive Ion Beams in Brazil facility at the University of S\~ao Paulo. The elastic scattering has been measured by detecting the $^{7}\mathrm{Be}$ scattered at forward angles in the laboratory system. The transfer reaction $^{9}\mathrm{Be}(^{7}\mathrm{Be},^{9}\mathrm{Be})^{7}\mathrm{Be}$ was identified by detecting the $^{9}\mathrm{Be}$ scattered at the same laboratory angles. The elastic angular distribution has been analyzed by optical model calculations using a Woods-Saxon form factor whose parameters have been varied to best reproduce the experimental data at forward angles. Coupled reaction channels calculations (CRC) have been performed to describe the transfer, considering the coupling to the transfer channel and including contributions to the ground state and to the first excited state of $^{7}\mathrm{Be}(1/2\ensuremath{-};429\phantom{\rule{0.16em}{0ex}}\mathrm{keV}$) in the final state. The spectroscopic amplitudes used in the CRC calculation have been derived from shell-model calculations. Similar CRC calculations were applied to existing $^{9}\mathrm{Be}(p,t)^{7}\mathrm{Be}$ data to check the consistency of our results results for the ($^{7}\mathrm{Be},^{9}\mathrm{Be}$) transfer reaction.

A large yield of $\ensuremath{\alpha}$ particles produced in the $^{120}\mathrm{Sn}(^{6}\mathrm{He},\ensuremath{\alpha})$ reaction was measured at 20.3-, 22.2-, 22.4-, and 24.5-MeV bombarding energies. The $\ensuremath{\alpha}$ particles are distributed over a broad energy range in the vicinity and below the elastic scattering $^{6}\mathrm{He}$ peak. Energy integrated $\ensuremath{\alpha}$-particle cross sections have been obtained at ${\ensuremath{\theta}}_{\text{lab}}={36}^{\ensuremath{\circ}},{40}^{\ensuremath{\circ}}$, and ${60}^{\ensuremath{\circ}}$. The $\ensuremath{\alpha}$ energy distributions have been analyzed at a fixed laboratory angle $(\ensuremath{\approx}{60}^{\ensuremath{\circ}})$ in terms of the reaction $Q$ value, considering the $2n$-transfer reaction kinematics $^{120}\mathrm{Sn}(^{6}\mathrm{He},\ensuremath{\alpha})^{122}\mathrm{Sn}$. A kinematical analysis of the $Q$-value distribution shows that the recoil system $^{120}\mathrm{Sn}+2n$ is formed in highly excited states in the continuum, at increasing excitation energies as the bombarding energy increases. It is shown that by using Brink's formula, the excitation energy depends on the transferred angular momentum following a linear relation with the square of the angular momentum, indicating that some kind of dinuclear rotating system is formed after the reaction.

We measured the $^{8}\mathrm{Li}(p,p)^{8}\mathrm{Li}$, $^{8}\mathrm{Li}(p,d)^{7}\mathrm{Li}$, and $^{8}\mathrm{Li}(p,\ensuremath{\alpha})^{5}\mathrm{He}$ reactions at low energies using the thick target inverse kinematics method, with a polyethylene ${[{\mathrm{CH}}_{2}]}_{n}$ target and a radioactive $^{8}\mathrm{Li}$ beam available at the Radioactive Ion Beams in Brazil facility of S\~ao Paulo. By measuring simultaneously several reaction channels $(p,p)$, $(p,d)$, and $(p,\ensuremath{\alpha})$, the still uncertain high-lying resonances of $^{9}\mathrm{Be}$, close to the proton threshold, can be studied and their parameters, such as energy, width, and spin parity can be more reliably determined. The experimental excitation functions of the reactions $^{8}\mathrm{Li}(p,p)^{8}\mathrm{Li}$, $^{8}\mathrm{Li}(p,d)^{7}\mathrm{Li}$, and $^{8}\mathrm{Li}(p,\ensuremath{\alpha})^{5}\mathrm{He}$ were analyzed using the $R$-matrix theory, which allows us to infer the properties of the resonances. Multichannel $R$-matrix analysis provides evidence for a significant clustering in the $(p,d)$ channel. The experimental data and the multichannel $R$-matrix analysis will be presented.

A description of the RIBRAS (radioactive ion beams in Brasil) facility is presented and the last experimental developments in the system are reported.

The $^{10}\mathrm{B}+^{120}\mathrm{Sn}$ reaction has been systematically studied at laboratory energies around the Coulomb barrier: ${E}_{\mathrm{LAB}}=31.5$, 33.5, 35.0, and 37.5 MeV. Cross sections for the elastic scattering and some reaction processes have been measured: excitation to the ${1}^{+}$ state of $^{10}\mathrm{B}$; excitation to the ${2}^{+}$ and ${3}^{\ensuremath{-}}$ states of $^{120}\mathrm{Sn}$; and the one-neutron pick-up transfer $^{120}\mathrm{Sn}(^{10}\mathrm{B},^{11}\mathrm{B})^{119}\mathrm{Sn}$. Coupled reaction channel (CRC) calculations have been performed in the context of the double-folding S\~ao Paulo potential. The theoretical calculations result in a good overall description of the experimental angular distributions. The effect on the theoretical elastic-scattering angular distributions of couplings to the inelastic and transfer states (through the CRC calculations) and to the continuum states (through continuum-discretized coupled-channels calculations) has been investigated.

The $^{10}\mathrm{B}+^{120}\mathrm{Sn}$ reaction has been investigated at ${E}_{\mathrm{Lab}}=37.5$ MeV. The cross sections for different channels, such as the elastic scattering, the excitation of the ${2}^{+}$ and ${3}^{\ensuremath{-}}\phantom{\rule{4pt}{0ex}}^{120}\mathrm{Sn}$ states, the excitation of the ${1}^{+}$ state of $^{10}\mathrm{B}$, and the $1n$ pick-up transfer, have been measured. One-step distorted-wave Born approximation and coupled-reaction-channels calculations have been performed in the context of the double-folding S\~ao Paulo potential. The effect of coupling the inelastic and transfer states on the angular distributions is discussed in the paper. In general, the theoretical calculations within the coupled-reaction-channels formalism yield a satisfactory agreement with the corresponding experimental angular distributions.

Experimental angular distributions for the $^{7}\mathrm{Li}\phantom{\rule{0.16em}{0ex}}+\phantom{\rule{0.16em}{0ex}}^{120}\mathrm{Sn}$ elastic and inelastic (projectile and target excitations) scattering, and for the neutron stripping reaction, have been obtained at ${E}_{\mathrm{LAB}}=20$, 22, 24, and 26 MeV, covering an energy range around the Coulomb barrier $({V}_{B}^{(\mathrm{LAB})}\ensuremath{\approx}21.4$ MeV). Coupled channel and coupled reaction channel calculations were performed and both describe satisfactorily the experimental data sets. The ${\frac{1}{2}}^{\ensuremath{-}}$ state $^{7}\mathrm{Li}$ inelastic excitation (using a rotational model), as well as the projectile coupling to the continuum $(\ensuremath{\alpha}$ plus a tritium particle) play a fundamental role on the proper description of elastic, inelastic, and transfer channels. Couplings to the one-neutron stripping channel do not significantly affect the theoretical elastic scattering angular distributions. The spectroscopic amplitudes of the transfer channel were obtained through a shell model calculation. The theoretical angular distributions for the one-neutron stripping reaction agreed with the experimental data.

The (p, p), (p, a) and (p, d) reactions on 8Li were measured at low energies. The experiment was performed using a thick [CH2]n target and a radioactive 8Li beam available at the RIBRAS facility of Sao Paulo . This experiment represents an upgrade of a previous experiment, where only the 8Li(p,a)5He cross section was measured. High lying resonances of 9Be, which are still uncertain, could be studied in this way. The detection of several reaction channels allows a reliable determination of the resonance parameters, such as energy, width and spin-parity. In the deuteron channel we could observe the same resonance decaying to d+7Ligs and to d+7Li∗. The properties of the resonances are determined by a R-matrix analysis, which provides evidence for a significant clustering as well in the (p, a) as in the (p, d) channels. The experimental data and the multi-channel R-matrix analysis will be presented.

We present angular distributions of the He 6 + Ni 58 scattering measured at three bombarding energies above the Coulomb barrier: E lab = 12.2 MeV , 16.5 MeV , and 21.7 MeV . The angular distributions have been analysed in terms of three- and four-body Continuum-Discretized Coupled-Channels calculations considering the effect of the 6 He breakup. A behaviour in the cross section at large angles has been observed which was reproduced only by the four-body Continuum-Discretized Coupled-Channels calculation.

An overview of the experiments performed at RIBRAS over the last year is presented. Elastic scattering and breakup reactions induced by light exotic projectiles on different targets have been measured and some results are presented here for the 120Sn(6He, α) reaction. Resonant scattering experiments have been performed with 10Be and 12C secondary beams on a CH2 thick target and the well known 12C+p resonance was identified. A gamma-particle experiment using a new system of LYSO scintillators to detect gammas was done.

In this work we present an elastic scattering angular distribution for the 8Li+58Ni system measured at Elab = 26.1 MeV. The 8Li beam was produced in the Radioactive Ion Beams in Brasil (RIBRAS) facility using the 7Li primary beam delivered by the 8-UD Pelletron accelerator. The angular distribution covers the angular range from 20 to 85 degrees in the center of mass frame. The data have been analysed by optical model and coupled channels calculations, including couplings to low-lying states in 8Li and the spin-orbit interaction. Our results indicate that the inclusion of the spin-orbit interaction in the calculations is important to describe the data at backward angles.

Esse trabalho consistiu na medida e análise de distribuições angulares do espalhamento elástico e inelástico para núcleos de massa A=10 em alvos de 58Ni e no desenvolvimento de novos feixes secundários radioativos para o sistema RIBRAS. As distribuições angulares do sistema 10B+58Ni foram medidas nas energias E(lab)= 19, 20, 21, 23, 24, 25 e 35 MeV, no laboratório Tandar na Argentina, enquanto a distribuição angular do sistema 10C+58Ni foi medida na energia E(lab)= 35.3 MeV, utilizando o sistema TWINSOL, da Universidade de Notre Dame, Estados Unidos. O formalismo de canais acoplados foi utilizado para estudar a influência da estrutura deformada do núcleo 10B e da estrutura Bruniana do núcleo 10C. Os resultados indicaram a importância desses efeitos, bem como a possível influência dos canais de transferências e breakup. This work consisted in the analysis and measurement of angular distributions for elastic and inelastic scattering of mass A=10 projectiles in 58Ni target, as well as in the development of new secondaries radioactive ion beams for the RIBRAS system. Angular distributions for the 10B+58Ni system were measured at E(lab)= 19, 20, 21, 23, 24, 25 and 35 MeV, at Tandar Laboratory in Argentina, while an angular distribution at E(lab)= 35.3 MeV for the 10C+58Ni was measured at the University of Notre Dame, USA, using the Twinsol system. The coupled channel formalism was used to investigate the influence deformed structure of the 10B and Brunian structure for 10C nucleus. The results indicated the importance of these effect as well as the possible influence of transfer and breakup channels. In this work the development of 10C, 14C and 12B beams were investigated for future use in the RIBRAS system.

An elastic backscattering experiment has been performed at energies below the Coulomb barrier to investigate static and dynamic effects in the interaction of He6 with Bi209. The measured cross sections are presented in terms of the dσ/dσRuth ratio, as a function of the distance of closest approach on a Rutherford trajectory. The data are compared with a three-body CDCC calculation and good agreement is observed. In addition, the critical distance of interaction was extracted. A larger value was obtained for the exotic He6 nucleus as compared with the weakly bound Li6 and Be9 nuclei and the tightly bound He4, C12, and O16 nuclei.

Full angular distributions for elastic and inelastic scattering of $^{11}\mathrm{B}$ on $^{58}\mathrm{Ni}$ have been measured at different bombarding energies around the Coulomb barrier. Measurement and analysis with coupled-channel calculations have been performed for the first time for a system with the tightly bound $^{11}\mathrm{B}$ as projectile on a medium mass target. In these calculations, the real part of the interaction potential between nuclei was represented by a parameter-free double-folding potential. To avoid the use of an imaginary potential at the surface, several inelastic transitions of the projectile and the target have been included in the coupling matrix. The result of these coupled-channel calculations are in very good agreement with all experimental angular distributions. The most important result was the striking influence on the reaction mechanism of the ground-state-spin reorientation of the $^{11}\mathrm{B}$ nuclei.

We present a quick description of RIBRAS (Radioactive Ion beams in Brazil), which is a superconducting double solenoid system, installed at the Pelletron Laboratory of the University of São Paulo and extends the capabilities of the original Pelletron Tandem Accelerator of 8MV terminal voltage (8UD) by producing secondary beams of unstable nuclei. The experimental program of the RIBRAS covers the study of elastic and inelastic scattering with the objective to study the interaction potential and the reaction mechanisms between weakly bound (RIB) and halo (6He and 8B) projectiles on light, medium and heavy mass targets. With highly purified beams, the study of resonant elastic scattering and resonant transfer reactions, using inverse kinematics and thick targets, have also been included in our recent experimental program., SCOPUS: cp.j, info:eu-repo/semantics/published

Elastic scattering angular distributions of the radioactive weakly bound $^{7}\mathrm{Be}$ on $^{27}\mathrm{Al}$ have been measured at energies near the Coulomb barrier. The interaction optical potential is investigated by using different potentials. Total reaction cross sections have also been obtained.

We present the results of the 8Li(p,α)5He and 8Li(p,p)8Li reactions measured at the RIBRAS (Radioactive Ion Beams in Brazil) system. The experiment was realized in inverse kinematics using a thick [CH2]n polyethylene target and an incident 8Li beam, produced by RIBRAS. Using the thick target method, the complete excitation function could be measured between Ecm = 0.2 - 2.1 MeV, which includes the Gamow peak energy region. The excitation function of the 8Li(p,α)5He reaction, populating resonances between 16.888 and 19.0 MeV in 9Be, was obtained[1] and the resonances were fitted using R-matrix calculations. This study shed light on spins, parities, partial widths and isospin values of high lying resonances in 9Be. The measurement of the resonant elastic scattering 8Li(p,p)8Li populating resonances in the same energy region can constrain the resonance parameters. Preliminary results of the elastic scattering are also presented. © Owned by the authors, published by EDP Sciences, 2014., SCOPUS: cp.p, info:eu-repo/semantics/published

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

Measurements of the p({sup 6}He,p) elastic scattering excitation function have been performed in the RIBRAS system using a {sup 6}He secondary beam and a CH{sub 2} polyethylene thick target. The motivation is to observe states of the compound nucleus {sup 7}Li in the excitation energy range of E{sub exc}{sup 7Li} = 10.8-11.8MeV, where the isobaric analog state of {sup 7}He ground state lies. Excitation functions have been obtained at three laboratory angles θ{sub lab} = 0°, 20°, and 25° which correspond to θ{sub c.m} = 180°, 140°, and 130°.

Elastic scattering measurements of 6He + 58Ni system have been performed at the laboratory energy of 21.7 MeV. The 6He secondary beam was produced by a transfer reaction 9Be (7Li, 6He) and impinged on 58Ni and 197Au targets, using the Radioactive Ion Beam (RIB) facility, RIBRAS, installed in the Pelletron Laboratory of the Institute of Physics of the University of Sao Paulo, Brazil. The elastic angular distribution was obtained in the angular range from 15° to 80° in the center of mass frame. Optical model calculations have been performed using a hybrid potential to fit the experimental data. The total reaction cross section was derived.

A description of the double solenoid system (RIBRAS) operating since 2004 in one of the beam lines of the Pelletron Laboratory of the Institute of Physics of the University of Sao Paulo is presented. The recent installation of the secondary scattering chamber after the second solenoid is reported and the first experiment in RIBRAS using both solenoids is described.

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 $+{\phantom{\rule{0.16em}{0ex}}}^{12}$C systems to infer the role of breakup in the elastic scattering. For the ${}^{10}$Be $+{\phantom{\rule{0.16em}{0ex}}}^{12}$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.

Angular distributions for the ${}^{9}\mathrm{Be}({}^{8}\mathrm{Li},{}^{9}\mathrm{Be}){}^{8}\mathrm{Li}$ elastic-transfer reaction have been measured with a 27-MeV $^{8}\mathrm{Li}$ radioactive nuclear beam. Spectroscopic factors for the $\ensuremath{\langle}{}^{9}\mathrm{Be}|{}^{8}\mathrm{Li}+p\ensuremath{\rangle}$ bound system were obtained from the comparison between the experimental differential cross sections and finite-range distorted-wave Born approximation calculations made with the code FRESCO. The spectroscopic factors so obtained are compared with shell-model calculations and other experimental values. Using the present value for the spectroscopic factors, cross sections and reaction rates for the ${}^{8}\mathrm{Li}(p,\ensuremath{\gamma}){}^{9}\mathrm{Be}$ direct proton-capture reaction of astrophysical interest were calculated in the framework of the potential model.

In earlier works, the fusion cross section for the 16O+16O reaction has been measured using different techniques. In the present work, we have obtained an experimental excitation function for 16O+16O using γ-ray spectroscopy. The measurements were performed at center-of-mass energies between 8.28 and 12.25 MeV. The theoretical predictions obtained with a coupled-channel model are consistent with the experimental data. From our analyses, the extrapolated S-factor value at 6.6 MeV, corresponding to the Gamow peak energy for core oxygen burning conditions, is about 3.6 × 1025 MeV barn.

A recent experiment has been performed in the double solenoid system Radioactive Ion Beams in Brasil (RIBRAS) by impinging a pure 6 He secondary beam on a thick CH 2 target to measure the 6 He + p excitation function. Results of this experiment will be presented.