The ECIS (Equations Couplées Itérations Séquentielles) code of Jacques Raynal continues to have an important role since its first version in the seventies. Its use to describe the elastic and ...inelastic scattering of light heavy ions at energies close to the Coulomb barrier is the first topic of this paper. Nuclear reactions with weakly bound stable and radioactive projectiles are described in the second topic, where the projectiles breakup is not taken into account in ECIS and a more recent formalism called Continuum Discretized Coupled Channels (CDCC) calculations is applied to them. The second topic also contains some results that were obtained at the Radioactive Ion Beams in Brasil (RIBRAS) facility, with a radioactive 2n-halo
6
He beam on light, medium mass, and heavy targets.
In several experiments, a system composed by two surface barrier detectors, one thin and one thicker, is used to identify the charge of a nucleus that is detected in this system. The nucleus loses ...part of its energy (
Δ
E
) in the thin detector and the remaining part (
E
) is left in the thick one. Since the energy loss depends on the charge, this process allows the identification of the nuclear charge. The energy loss also depends on the mass of the particle, but with a lower degree of sensitivity. Therefore, the identification of the nuclear mass is much more difficult. In this paper, we present a method to treat the data in order to optimize the mass discrimination of particles detected in
Δ
E
–
E
systems.
The half-life of the second excited state (5/2− at 59.54 keV) of 237Np was measured with high precision and reliability using the coincidence method with fast scintillators and a fully digital-based ...electronic data acquisition system. The alpha particle from an 241Am source was measured in coincidence with the gamma rays emitted by the daughter 237Np nucleus. This measurement also illustrates the use of new LYSO(Ce) scintillators in particle-gamma experiments.
Experiments with A = 6–8 exotic beams in RIBRAS Lichtenthäler, R.; Santos, O. C. B.; Serra, A. ...
The European physical journal. A, Hadrons and nuclei,
03/2021, Letnik:
57, Številka:
3
Journal Article
Recenzirano
Experiments with secondary radioactive beams
6
He,
7
Be,
8
Li and
8
B on several targets have been performed in recent years at the Radioactive Ion Beams facility in Brasil (RIBRAS). We present ...results of elastic scattering and reaction measurements performed with this facility. A preliminary Coulomb excitation experiment using gamma-particle coincidence technique is described.
The
8
Li +
9
Be quasi-elastic angular distribution and the
9
Be(
8
Li
,
7
Li)
X
inclusive reaction have been measured at E
Lab
=
23.8
MeV bombarding energy using the RIBRAS facility. In addition to ...the
8
Li scattering peak, a large yield of
7
Li particles has been observed in the identification spectra, presenting a wide energy distribution centered around and below the energy of the
8
Li quasi-elastic peak. The
7
Li angular and energy distributions have been obtained and analysed assuming that these particles stem from two different mechanisms: (
i
) the elastic breakup (EBU), in which the projectile dissociates into
7
Li+
n
and the
9
Be target remains in its ground state and (
ii
) the nonelastic breakup (NEB) which accounts for absorptive processes between the neutron and the target, including the neutron transfer. The
7
Li angular and energy distributions have been analyzed by the Ichimura, Austern and Vincent (IAV) model for NEB, and the Continuum-Discretized Coupled-Channels (CDCC) method for the EBU. The theoretical results are in good agreement with the experimental data.
Abstract
A feasibility study of two-neutron transfer reactions, using
12
C and
19
F targets, was performed. In this experiment, a
6
He beam at 20 MeV incident energy was delivered by the RIBRAS ...facility. The main goal of this work was to test the RIBRAS system, operated in a single-solenoid mode, to investigate (
6
He,
α
) reactions in light nuclei. The excitation function of the
14
C nucleus, populated by the
12
C(
6
He,
α
) reaction, was extracted from the data. Evidence of
nn
-transfer reactions populating the ground state and the first
0
1
+
state in
14
C were observed. However, the present spectrum might have contribution from other reaction channels such as the
6
He breakup. Future experiments with the RIBRAS dual-solenoid mode will improve the quality of the data by reducing a significant amount of background.
We present angular distributions of the He6+Ni58 scattering measured at three bombarding energies above the Coulomb barrier: Elab=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 6He 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.
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.
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