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The unbound proton-rich nuclei 16 F and 15 F are investigated experimentally and theoretically. Several experiments using the resonant elastic scattering method were performed at GANIL with radioactive beams to determine the properties of the low lying states of these nuclei. Strong asymmetry between 16 F– 16 N and 15 F– 15 C mirror nuclei is observed. The strength of the n u c l e o n - n u c l e o n effective interaction involving the loosely bound proton in the s 1 / 2 orbit is significantly modified with respect to their mirror nuclei 16 N and 15 C. The reduction of the effective interaction is estimated by calculating the interaction energies with a schematic zero-range force. It is found that, after correcting for the effects due to changes in the radial distribution of the single-particle wave functions, the mirror symmetry of the n - p interaction is preserved between 16 F and 16 N, while a difference of 63% is measured between the p - p versus n - n interactions in the second excited state of 15 F and 15 C nuclei. Several explanations are proposed. [ABSTRACT FROM AUTHOR]

The unbound nucleus 18Na, the intermediate nucleus in the two-proton radioactivity of 19Mg, is studied through the resonant elastic scattering 17Ne(p,17Ne)p. The spectroscopic information obtained in this experiment is discussed and put in perspective with previous measurements and the structure of the mirror nucleus 18N. [ABSTRACT FROM AUTHOR]

New results on two-proton radioactivity, predicted 50 years ago and observed for the first time in 2002, are presented. These results have been obtained with a time projection chamber at the LISE3 facility of GANIL. After 45Fe, the direct observation of the two protons for 54Zn is only the second such case from a long lived ground-state two-proton emitter. The new results are discussed and future perspectives highlighted. [ABSTRACT FROM AUTHOR]

Proton-rich isotopes of zinc and germanium, 57Zn and 61Ge, have been produced by fragmentation of a 70Ge beam at the LISE3 facility of GANIL. Their main decay characteristics have been studied after implantation in a double-sided silicon strip detector. In addition, the production cross-sections of proton-rich isotopes in the copper-to-germanium region have been determined. These cross-sections are much lower than predicted by the EPAX formula. These findings question to some extent the production rates expected for present and future fragmentation facilities. [ABSTRACT FROM AUTHOR]

The excitation function for the elastic-scattering reaction p(18Ne, p)18Ne was measured with the first radioactive beam from the SPIRAL facility at the GANIL laboratory and with a solid cryogenic hydrogen target. Several broad resonances have been observed, corresponding to new excited states in the unbound nucleus19Na. In addition, two-proton emission events have been identified and are discussed. [ABSTRACT FROM AUTHOR]

The reduction of the neutron spin-orbit (SO) splitting 2 p 3 / 2 − 2 p 1 / 2 between the 41Ca and 35Si isotones is a unique feature throughout the chart of nuclides, as the SO splitting usually increases with decreasing A. The way it is reduced, either gradually between 41Ca and 35Si or abruptly between 37S and 35Si, as well as the origin of its reduction, whether from the weak binding energy of the p states or from the sudden depletion in the central proton density moving to 35Si, are subject of debate. The results reported here using the self-consistent Covariant Energy Density Functional calculations with the DD-ME2 parametrization rather point to an abrupt, local decrease in 35Si, and to the large dominance of the central density depletion effect. It is concluded that weak binding, central density depletion as well as correlations must be taken into account to fully evaluate the amplitude and causes of this SO splitting reduction. To broaden the scope of the present work, discussions also include the recent experimental results of proton and neutron SO splittings around 132Sn and 56Ni. [ABSTRACT FROM AUTHOR]

Particle decay of 69Br and 65As was observed through β-delayed proton emission of 69Kr and 65Se, respectively. Decay spectroscopy was performed through β-p correlations using a position-sensitive silicon-implantation detector surrounded by a γ-ray detector array. A β-decay half-life of 27(3) ms was measured for 69Kr and 33(4) ms for 65Se. The 69Kr ground state decays by a superallowed transition to its unbound isobaric analog state in 69Br which immediately decays by a 2.97(5)-MeV proton group to the first excited state in 68Se at 854.2 keV. This chain of decays constrains both the mass and spin of the 69Kr ground state. We observed no evidence of ground-state proton decay from 69Br. [ABSTRACT FROM AUTHOR]

The two protons emitted in the decay of 54Zn have been individually observed for the first time in a time projection chamber. The total decay energy and the half-life measured in this work agree with the results obtained in a previous experiment. Angular and energy correlations between the two protons are determined and compared to theoretical distributions of a three-body model. Within the shell model framework, the relative decay probabilities show a strong contribution of the p2 configuration for the two- proton emission. After 45Fe, the present result on 54Zn constitutes only the second case of a direct observation of the ground state two-proton decay of a long-lived isotope. [ABSTRACT FROM AUTHOR]

Abstract: In a series of experiments at the SISSI/LISE3 facility of GANIL conducted between 1999 and 2004, we have collected decay information for proton-rich nuclei between 36Ca and 56Zn. The data allowed us to study the decay properties of 26 nuclei. The main experimental information obtained for all nuclei is their β-decay half-life and their total β-delayed proton emission branching ratio. For many nuclei, individual proton groups and γ rays were identified and allowed us to establish first partial decay schemes for some of the nuclei studied. In addition, mass-excess values have been determined for some of the nuclei by means of the isobaric multiplet mass equation. For 50Ni, the decay via β-delayed two-proton emission could be tentatively identified. The decay of 49Ni allowed for the first time to identify the first state in 48Fe. The experimental data are confronted to model predictions for the half-life and the mass-excess values. [Copyright &y& Elsevier]