GONZÁLEZ ÁLVAREZ , Marcos Aurelio

We have studied volume integrals of the central part of optical potentials extracted from data analyses for a variety of light and heavy systems. The data-extracted integrals present a quite simple behavior as a function of the relative velocity between target and projectile. This behavior is system independent and, therefore, it reflects a...

We have analyzed elastic scattering angular distributions and total reaction cross sections of the exotic nuclei Li9,11 on Pb208, at energies below and above the Coulomb barrier. For this purpose, we have used an optical potential with no adjustable parameters, composed by the nuclear São Paulo potential, derived from the nonlocal nature of the...

The elastic and α-production channels for the 6He+208Pb reaction are investigated at energies around the Coulomb barrier (Elab=14, 16, 18, 22, and 27 MeV). The effect of the two-neutron transfer channels on the elastic scattering has been studied within the Coupled-Reaction-Channels (CRC) method. We find that the explicit inclusion of these...

We present some recent applications of the Continuum-Discretized Coupled-Channels (CDCC) and Coupled-Reaction-Channels (CRC) methods to the study of reactions induced by weakly-bound nuclei on stable targets. The methods are applied to the scattering of the Borromean nucleus 6He at energies around the Coulomb barrier. Elastic scattering data...

We present an Optical Model (OM) study of 6He on 208Pb elastic scattering data, measured at laboratory energies around the Coulomb barrier (Elab=14, 16, 18, 22, and 27 MeV) [1]. For the projectile-target bare interaction, we use the microscopic São Paulo Potential (SPP). This bare interaction is supplemented with a Coulomb Dipole Polarization...

The γ spectroscopy of 25, 27 Ne and 26, 27 Na was studied from the reaction of 26 Ne with a deuterium target in inverse kinematics at 9.7 MeV/nucleon. The selectivity of the (d,p), (d,t), and (d,n) transfer reactions provides new spectroscopic information on low-lying states. The validity of the sd shell-model space for these nuclei isdiscussed.

We report on systematical optical model (OM) and continuum discretized coupled channel (CDCC) calculations applied to describe the elastic scattering angular distributions of exotic and stable nuclei projectiles on heavy targets. Our optical potential (OP) is composed of the nuclear microscopic double folding São Paulo potential (SPP), derived...

This paper presents the design, implementation, and measurements of a complete electronic frontend intended for high-resolution spatial detection of ion beams at counting rates higher than 106 particles per second (p/s). The readout system is made up of three main multichannel building blocks, namely, a transimpedance preamplifier, a...

The feasibility studies of the slowed down beam setup involving deceleration of a 64Ni beam at 250 MeV/u to 13 MeV/u in a thick Al degrader was performed at the FRagment Separator (FRS) at GSI. The experimentally measured energy spread and the nuclear reaction yields in the degrader are in good agreement with simulations.

New accelerators like SPIRAL2 (GANIL, France) or FAIR (GSI, Germany) will be soon constructed, and they will be able to produce radioactive ion beams (RIB) with high intensities of current (≥106pps). These beams, at low energy, lower than 20 MeV/n, usually have high emittance, which imposes the use of tracking detectors before the target in...

A large yield of α particles produced in the 120 Sn ( 6 He , α ) reaction was measured at 20.3-, 22.2-, 22.4-, and 24.5-MeV bombarding energies. The α particles are distributed over a broad energy range in the vicinity and below the elastic scattering 6 He peak. Energy integrated α -particle cross sections have been obtained at...

The two-proton radioactivity of the previously unknown 19Mg ground-state is observed by tracking the decay products in-flight. The trajectories of the 2p-decay products, 17Ne+p+p, have been measured by using tracking micro-strip detectors which allowed to reconstruct the 2pdecay vertices and fragment correlations. The half-life of 19Mg deduced...

The 10 B + 120 Sn reaction has been systematically studied at laboratory energies around the Coulomb barrier: E 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 B ; excitation to the 2 + and 3 − states of 120 Sn ; and the...

We measured the 8 Li ( p , p ) 8 Li , 8 Li ( p , d ) 7 Li , and 8 Li ( p , α ) 5 He reactions at low energies using the thick target inverse kinematics method, with a polyethylene [ CH 2 ] n target and a radioactive 8 Li beam available at the Radioactive Ion Beams in Brazil facility of São Paulo. By measuring simultaneously several...

We have developed a model for the nuclear interaction which is based on the effects of the Pauli nonlocality. In earlier works, we have successfully used this interaction to describe the elastic scattering for several systems in a very wide energy range. In the present work, we have checked the validity of the same interaction in...

Elastic scattering differential cross sections were measured for the 28Si158Ni system at sub-barrier energies. The corresponding nuclear potential was compared with earlier results of systems like A158Ni. The present data also allowed the determination of the 28Si nuclear density through an unfolding method. The experimentally extracted 28Si...

Results of irradiation of thin Chemical Vapor Deposition (CVD) diamond detectors with low energy: p,α and 7Li beams are presented. Energy resolution: ΔE/E<1% of a single crystal detector was achieved. A coincident measurement with two diamond detectors showed time resolution of 100 ps and efficiency above 70%. Despite a high beam flux reaching...

We have observed the two-proton radioactivity of the previously unknown 19Mg ground state by tracking the decay products in-flight. For the first time, the trajectories of the 2p-decay products, 17Ne+p+p, have been measured by using tracking microstrip detectors which allowed us to reconstruct the 2p-decay vertices and fragment correlations....

Quasi-elastic scattering of 6He at E_lab=27 MeV from 197Au has been measured in the angular range of 6-72 degrees in the laboratory system employing LEDA and LAMP detection systems. These data, along with previously analysed data of 6He + 208Pb at the same energy, are analyzed using Optical Model calculations. The role of Coulomb dipole...

Elastic scattering and transfer cross sections for the 7 Be + 9 Be system have been measured at E lab = 23.1 MeV using the 7 Be radioactive secondary beam produced at Radioactive Ion Beams in Brazil facility at the University of São Paulo. The elastic scattering has been measured by detecting the 7 Be scattered at forward angles in the...

The spectroscopy of 27Ne has been investigated through the one-neutron transfer reaction 26Ne(d,p)27Ne in inverse kinematics at 9.7 MeV/nucleon. The results strongly support the existence of a low-lying negative parity state in 27Ne, which is a signature of a reduced sd-fp shell gap in the N=16 neutron-rich region, at variance with stable nuclei.

The nature of the 1− and 2− excited states in 10Be is studied using the 11Be(p, d) transfer reaction in inverse kinematics at 10A MeV at TRIUMF ISAC-II, in particular to assess whether either of them can be considered as an excited halo state. The angular distributions for both states are extracted using deuteron-γ coincidences and analyzed...