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The odd-odd 88 37Rb51 and 86 35Br51 nuclei have been produced as fission fragments in the fusion reaction 18O$ + $208Pb at 85MeV bombarding energy and studied with the Euroball IV array. Their high-spin level schemes have been built from the triple $ \gamma$ -ray coincidence data and $ \gamma$ - $ \gamma$ angular correlations have been analyzed in order to assign spin and parity values to many observed states. The proposed configurations involve proton excitations from three sub-shells located close to the Fermi levels, $ \pi$ p3/2 , $ \pi$ f5/2 , and $ \pi$ g9/2 , the $ \nu$ d5/2 neutron acting as a spectator. The residual $ \pi$ $ \nu$ interactions are extracted from the multiplets of states resulting from the $ \pi$ p3/2 $ \nu$ d5/2 and $ \pi$ f5/2 $ \nu$ d5/2 configurations. The empirical values of the latter are discussed and compared to those known in two similar configurations having jp = jn with lp = ln + 1 , where the role of the tensor force had been highlighted. [ABSTRACT FROM AUTHOR]

High-spin states in the 142Ce and 140Ba nuclei have been populated in the 12C + 238U and 18O + 208Pb fusion-fission reactions at 90MeV and 85MeV bombarding energy, respectively. The emitted γ -radiation was detected using the Euroball III and IV arrays. The high-spin yrast and near-to-yrast structures of 142Ce have been considerably extended. The level scheme of 140Ba has been extended by six new levels. The newly observed structures in these N = 84 isotones are discussed by analogy with the neighbouring nuclei. [ABSTRACT FROM AUTHOR]

The121,123,125,127Sb nuclei have been produced as fission fragments in three reactions induced by heavy ions:12C +238U at 90 MeV bombarding energy,18O +208Pb at 85 MeV, and31P +176Yb at 152 MeV. Their level schemes have been built from gamma rays detected using the EUROBALL III and IV arrays. High-spin states of123,125,127Sb nuclei have been identified for the first time. Moreover isomeric states lying around 2.3 MeV have been established in123,125,127Sb from the delayed coincidences between the fission fragment detector SAPhIR and the gamma array. All the observed states can be described by coupling ad5/2 org7/2 proton to an excited Sn core involving either vibrational states or broken neutron pairs. [ABSTRACT FROM AUTHOR]

The84Se nucleus has been produced as fission fragment in the fusion reaction18O +208Pb at 85MeV bombarding energy and studied with the Euroball IV array. Medium-spin states of this neutron-rich isotope have been identified for the first time. Its level scheme has been obtained up to 4.9MeV excitation energy and spinI~ 7?. Its structure is interpreted by analogy with those of the stable heavier isotones. The evolution of the energy of theN= 50 neutron-core excitation is discussed as a function of the proton number. [ABSTRACT FROM AUTHOR]

High-spin states from the three-quasiparticle (3qp) configuration &paig9/2vh211/2 in the neutronrich 49In isotopes have been studied in the framework of shell model calculation. The two-body residual interactions needed for such calculations have been extracted from the level schemes of neighbouring nuclei. In particular, the evolution of the proton-neutron &paig9/2vh211/2 interaction has been analyzed as a function of the neutron number. When the gradual filling of the vh211/2 sub-shell is taken into account, the results of the 3qp configuration calculations are found to be very close to the experimental positive-parity yrast states located above 2 MeV excitation energy in 113-121In. Moreover, several long-lived isomeric states with positive parity are predicted in 123, 125, 127In. [ABSTRACT FROM AUTHOR]

The 110,112 Rh and 114',16Ag nuclei have been produced as fission fragments in the fusion reaction 18 + 208Pb at 85 MeV. Their level schemes have been built from gamma-rays detected using the Euroball IV array. High-spin states of these neutron-rich nuclei have been identified for the first time. The yrast structures consist of rotational bands in which the odd proton occupies the πg9/2 sub-shell and the odd neutron the vh11/2 sub-shell. The evolution of the πg9/2 ® vh11/2 band structure is analyzed as a function of the neutron number. [ABSTRACT FROM AUTHOR]

We report the results of an experiment, realized with the EUROBALL IV spectrometer, in which superdeformed (SD) states have been populated in 197,198Pb nuclei. Crosstalk transitions between two signature partner SD bands in 197Pb have been observed with an established Mi character, giving access to the magnetic properties of the v[752]5/2 intruder orbital. Six new SD bands have been identified in 197,198Pb. The results are interpreted in the framework of cranked Hartree-Fock calculations. A mixing between quasi-particle excitations and an octupole vibration is suggested in the two SD isotopes. [ABSTRACT FROM AUTHOR]

The nucleus 35S has been studied by in-beam γ-ray spectroscopy using the 24Mg(14N,3p) fusion-evaporation reaction at Elab = 40 MeV. A level scheme extended up to Jπ = 17/2+ at 8023 keV and Jπ = 13/2- at 6352 keV has been established. Lifetimes of six excited states have been determined by applying the Doppler shift attenuation method. The experimental data have been compared with the results of large-scale shell model calculations performed using different effective interactions and model spaces allowing particle-hole excitations across the N = Z = 20 shell gap. [ABSTRACT FROM AUTHOR]

The high-spin states of the two neutron-rich nuclei 88Kr52 and 89Rb52 have been studied from the 18O+208Pb fusion-fission reaction. Their level schemes were built from triple β-ray coincidence data, and β-β angular correlations were analyzed in order to assign spin and parity values to most of the observed states. The two level schemes evolve from collective structures to single-particle excitations as a function of the excitation energy. Comparison with results of shell-model calculations gives the specific proton and neutron configurations which are involved to generate the angular momentum alongthe yrast lines. [ABSTRACT FROM AUTHOR]

γ-ray production cross sections have been measured in proton irradiations of N, Ne, and Si and α-particle irradiations of N and Ne. In the same experiment we extracted also line shapes for strong γ-ray lines of 16O produced in proton and α-particle irradiations of O. For the measurements gas targets were used for N, O, and Ne and a thick foil for Si. All targets were of natural isotopic composition. Beams in the energy range up to 26 MeV for protons and 39 MeV for α particles were delivered by the Institut de Physique Nucléaire-Orsay tandem accelerator. The γ rays were detected with four high-purity Ge detectors in the angular range 30° to 135°. We extracted 36 cross-section excitation functions for proton reactions and 14 for α-particle reactions. For the majority of the excitation functions no other data exist to our knowledge. Where comparison with existing data was possible, usually a very good agreement was found. It is shown that these data are very interesting for constraining nuclear reaction models. In particular, the agreement of cross section calculations in the nuclear reaction code talys with the measured data could be improved by adjusting the coupling schemes of collective levels in the target nuclei 14N, 20,22Ne, and 28Si. The importance of these results for the modeling of nuclear γ-ray line emission in astrophysical sites is discussed. [ABSTRACT FROM AUTHOR]