No abstract available

No abstract available

[en] At LNS are available radioactive beams in an energy range from few MeV/A to 40 MeV/A. Low energy beams are provided by the EXCYT facility [1]; 8^Li was already produced with relatively good intensity, and also 9^Li is available. Intermediate energy beams are produced and selected using the in flight fragmentation method, with the FRIBS system [2]. Using these beams and the 4p detector CHIMERA [3], we want to study excitation and decay of resonances in light exotic nuclei populated with transfer, pick-up and other reaction mechanisms. Measurements concerning 1^0Li and 1^1Be nuclei will be accomplished during 2009. Some preliminary results obtained with stable and unstable beams will be presented.(author)

[en] A multicounter system for high-multiplicity γ-ray cascade measurements has been designed. The detection system, consisting of 12NaI(Tl) scintillation counters, is described. Tests concerning high-multiplicity cascade detection probability and cross-talk are discussed. Performances of the multiplicity filter in investigations on nuclei at very high spin produced in heavy-ion fusion are presented

[en] The study of the Giant Dipole Resonance (GDR) excited in hot nuclei allows to follow the evolution of collective motion with increasing nuclear temperature. A brief review of the characteristics of the GDR excited in nuclei with excitation energies up to ∝500 MeV is given. The results of recent experiments in which very hot nuclei have been studied with a nearly 4π detector are presented. Gamma-rays, light charged particles and evaporation residues emitted from hot nuclei of mass around 115 and excitation energies above 300 MeV, formed in the ³⁶Ar+⁹⁰Zr at 27 MeV/u and ³⁶Ar+⁹⁸Mo at 37 MeV/u reactions, have been measured with the MEDEA multidetector. The γ-ray yield from the decay of the Giant Dipole Resonance in these nuclei has been found to be independent of excitation energy and bombarding energy. The measured γ-ray spectra are compared with statistical calculations encompassing several recent theoretical models for the quenching of gamma-ray emission from the dipole resonance at very high temperatures. The best agreement with the data is obtained by assuming a cut-off of the resonance γ-emission above an excitation energy of 250 MeV. (orig.)

[en] Short communication

[en] In the framework of the HADES (High Acceptance DiElectron Spectrometer) collaboration the authors are developing the Time Of Flight (TOF) wall subdetector. In order to efficiently select events with e⁺e^- pairs produced in the nuclear matter, the TOF wall must be able to resolve electrons from pions up to 0.5 GeV/c and from protons up to 2 GeV/c. Because the short flight path of about 2m requires a 100--150 ps time resolution, the authors are building a granular system made of scintillator rods readout on both ends by means of photomultipliers, capable of such performance

[en] The energetic proton emission has been investigated as a function of the reaction centrality for the system ⁵⁸Ni+⁵⁸Ni at 30AMeV. Extremely energetic protons (E^NN_p≥130 MeV ) were measured and their multiplicity is found to increase almost quadratically with the number of participant nucleons, thus indicating the onset of a mechanism beyond one- and two-body dynamics

[en] The Gamow-Teller strength distributions of ${}^{116}$Sb and ${}^{122}$Sb were measured with the ${}^{116,122}$Sn(${}^3$He, t)${}^{116,122}$Sb charge-exchange reactions at 140 MeV/u. The measurements were carried out at the Research Center for Nuclear Physics (RCNP) at Osaka University in Osaka, Japan using the Grand Raiden spectrometer. The data were analysed by Multipole-Decomposition Analysis (MDA). The Gamow-Teller strengths summed up to 28 MeV are (38±7)% and (48±6)% of the Ikeda sum rule for ${}^{116}$Sb and ${}^{122}$Sb, respectively, if the quasi-free scattering (QFS) contribution is not subtracted. These percentages are (29±7)% and (35±5)%, respectively, if the QFS contribution is maximally subtracted. These results were compared to those from previous measurements of the same isotopes, to recent measurements of ${}^{150}$Pm, and to a Quasi-particle Random-Phase Approximation (QRPA) calculation with Quasi-Particle Vibration Coupling (QPVC). The data suggest that the true QFS contribution is small for ${}^{116}$Sb, but are inconclusive about whether the QFS contribution is small or significant for ${}^{122}$Sb. Therefore, these data may provide an interesting test for the general quenching phenomenon of the Gamow-Teller Resonance (GTR). However, more research to reveal the nature of the QFS contribution is still needed on both the experimental and the theoretical side.

No abstract available