Search

The 9Be(6Li,d)13C reaction was used to investigate alpha resonant states in 13C up to 15 MeV of excitation. The reaction was measured at a bombarding energy of 25.5 MeV employing the Sao Paulo Pelletron‐Enge‐Spectrograph facility and the nuclear emulsion detection technique. An energy resolution of 50 keV was obtained. Several narrow alpha resonant states not previously measured were detected, in particular the one at the (3α+n) threshold populated by an L = 2 transfer, revealing a 9Be+α component for the 1/2− cluster state candidate at this threshold. Experimental angular distributions are presented in comparison with DWBA predictions.

The MAGNEX large‐acceptance ray‐tracing magnetic spectrometer has recently been used with beams from the INFN‐LNS Tandem accelerator. After an accurate commissioning, the instrument has started an ambitious experimental program. In the first experiment the 19F(7Li,7Be)19O charge‐exchange reaction was studied at 52 MeV incident energy. The 19O excitation energy spectrum was reconstructed and the angular distributions measured. The second experiment was aimed at the study of the 15C via the 13C(18O,16O)15C reaction at 84 MeV incident energy. The ejectiles where detected at forward angles and mass identified by means of an innovative technique. The 15C excitation energy spectra up to about 20 MeV were obtained with a 250 keV FWHM energy resolution. In addition to several known states, the spectra show two unknown resonant‐like structures at 11.4 and 14.0 MeV. The strong population of these structures, together with the measured widths, could indicate the collective nature of these states associated to a corr...

The 9Be(6Li,d)13C reaction was used to investigate alpha resonant states in 13C up to 13 MeV of excitation. The reaction was measured at a bombarding energy of 25.5 MeV employing the Sao Paulo Pelletron‐Enge‐Spectrograph facility and the nuclear emulsion detection technique. The resolution of 50 keV allowed for the separation of the resonant contributions to the known 7/2− at 10.753 MeV and (5/2−) at 10.818 MeV 13C states. The alpha resonance seen at the (3α+n) threshold was not previously reported. The experimental angular distributions are presented in comparison with DWBA predictions.

A systematic study of the nuclei that can be described as an integer number of α particles plus three neutrons via the (7Li,7Be) reaction at about 8 MeV/u has shown the presence of Bound States Embedded in the Continuum in the energy spectra. These are experimental signatures of the dynamical correlations of an easily polarizable core with a single‐particle state of the valence neutron.

The MAGNEX large‐acceptance spectrometer was commissioned with beams from the LNS Tandem. First results of physical interest are presented. The obtained 10−3 energy resolution confirms the ambitious characteristic of the calculations and allows considering the instrument as an ideal tool for future studies in the field of nuclear spectroscopy and reaction mechanisms at incident energies not far form the Coulomb barrier.

Neutron separation energies in 91Zr, 92Zr, 93Zr and 95Zr were determined by measurements of relative Q-values for (d, p) reactions on Zr isotopes. A comparison is made with separation energies derived from a previous measurement of (d, t) reaction Q-values. The neutron separation energy in 95Zr disagrees by three standard deviations with the adjusted value in the 1977 Atomic Mass Evaluation.

Heavy-ion one-nucleon transfer reactions are promising tools to investigate single-particle configurations in nuclear states, with and without the excitation of the core degrees of freedom. An accurate determination of the spectroscopic amplitudes of these configurations is essential for the study of other direct reactions as well as beta-decays. In this context, the 76Se(18O,17O)77Se one-neutron transfer reaction gives a quantitative access to the relevant single particle orbitals and core polarization transitions built on 76Se. This is particularly relevant, since it provides data-driven information to constrain nuclear structure models for the 76Se nucleus. The excitation energy spectrum and the differential cross section angular distributions of this nucleon transfer reaction was measured at 275 MeV incident energy for the first time using the MAGNEX large acceptance magnetic spectrometer. The data are compared with calculations based on distorted wave Born approximation and coupled channel Born approximation adopting spectroscopic amplitudes for the projectile and target overlaps derived by large-scale shell model calculations and interacting boson-fermion model. These reactions are studied in the frame of the NUMEN project. The NUMEN (NUclear Matrix Elements for Neutrinoless double beta decay) project was conceived at the Istituto Nazionale di Fisica Nucleare–Laboratori Nazionali del Sud (INFN-LNS) in Catania, Italy, aiming at accessing information about the nuclear matrix elements (NME) of neutrinoless double beta decay (0νββ) through the study of the heavy-ion induced double charge exchange (DCE) reactions on various 0νββ decay candidate targets. Among these, the 76Se nucleus is under investigation since it is the daughter nucleus of 76Ge in the 0νββ decay process.