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The spectroscopy of fission fragments, obtained by the 18O+208Pb fusion-fission reaction at 85 MeV bombarding energy, has been performed with the Euroball IV γ-array. High-spin states in many neutron-rich Se, Br, Kr and Rb of the 78Ni region nuclei have been identified for the first time. Several physical aspects which govern the nuclear structure in this mass region are underlined thanks to the new results. Among those, empirical values of the residual proton-neutron interactions have been extracted for the πf5/2xvd5/2 and πp3/2xvd5/2 configurations. [ABSTRACT FROM AUTHOR]

A fusion-evaporation experiment has been performed with a SPIRAL 76Kr radioactive beam in order to study the deformation of rare-earth nuclei near the proton drip-line. The experimental setup consisted in the EXOGAM γ-array, coupled to the light-charged particles (LCP) DIAMANT detector and to the VAMOS heavy-ion spectrometer. The difficulties inherent to such measurements are enlightened. The coupling between EXOGAM and DIAMANT has been used to decrease the huge background caused by the radioactivity of the beam. It further permits assigning new γ-ray transitions to specific residual nuclei. A γ-ray belonging to the 130Pm level scheme has thus been observed for the first time. [ABSTRACT FROM AUTHOR]

The 84,85Br nuclei have been produced as fission fragments in the fusion reaction 18O+208Pb at 85 MeV bombarding energy and studied with the Euroball IV array. The high-spin states of the odd-odd 84Br nucleus have been identified for the first time. From angular correlation analysis, spin values have been assigned to most of the 85Br excited states up to 4 MeV. All observed states in 84,85Br can be described by various proton excitations involving at least the two sub-shells (πf5/2 and πp3/2) located just above the Z = 28 shell closure. [ABSTRACT FROM AUTHOR]

High-spin states of 84Se, produced as a fission fragment in the fusion-fission reaction 18O+208Pb and studied with the EUROBALL IV array, have been identified for the first time. Their interpretation gives new insights about the evolution of the N=50 shell gap at the vicinity of 78Ni. To characterize this evolution, it would be worth using a new device devoted to the high-spin studies of neutron-rich nuclei produced by asymetric fission modes. Such dedicated studies are reported in a second part. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The structure of the very neutron-deficient rare-earth nuclei has been investigated in the first experiment with the EXOGAM gamma array coupled to the DIAMANT light charged particle detector using radioactive beam of 76Kr delivered by the SPIRAL facility. Very neutron-deficient Pr, Nd and Pm isotopes have been populated at rather high spin by the reaction 76Kr + 58Ni at a beam energy of 328 MeV. We report here the first results of this experiment. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

High-spin states of 84Se, produced as a fission fragment in the fusion-fission reaction 18O+208Pb, have been identified for the first time thanks to the EUROBALL IV array. The excitation energies of three of these states, interpreted as being due to the (νg9/2-1 νd5/2+1) neutron-core excitation, give new insights about the evolution of the N=50 shell gap at the vicinity of 78Ni. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

An experiment has been performed using a SPIRAL 76Kr radioactive beam at GANIL to investigate rare-earth nuclei near the proton drip-line. The EXOGAM gamma array was coupled with the DIAMANT light charged-particle detector and the VAMOS spectrometer. We report here on the powerful of this setup to extract fusion-evaporation γ-rays from a large beam contamination. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]