MEASUREMENT OF HIGH-ENERGY GAMMA RAYS TO STUDY THE DYNAMICAL DIPOLE EMISSION AND THE ISOSPIN MIXING

The study of the collective properties of a nuclear system is a powerful tool to understand the structure which lies inside the nucleus. A successful technique which was used in this field is the measurement of the gamma decay of the collective Giant Dipole Resonance (GDR) as a probe to understand structural or dynamical aspect of the nucleus. In this work, using fusion-evaporation reactions, it was possible to study i) the yield of the high-energy gamma-ray emission of the Dynamical Dipole (DD) for the system 16O + 116Sn at 12 MeV/u, which takes place during the compound nucleus formation process if there an N/Z asymmetry; and ii) the degree of isospin mixing at finite temperature in the decay of N=Z nucleus 80Zr at T=2.4 MeV using the 40Ca + 40Ca fusion-evaporation reaction. Both experiments were performed at the Laboratori Nazionali di Legnaro using the HECTOR and its upgraded version (HECTOR+) arrays coupled to the GARFIELD array and to the AGATA Demonstrator respectively. The data on the measurement of the DD total yield shows that it has a weak but evident dependence on the beam energy, reproduced by theoretical calculations. These data does not confirm the rise and fall behavior present in previous work (not explained by theory). The preliminary analysis (detector calibration, detector performance and data reduction) will be described for the isospin mixing experiment. In such experiment an array of large volume LaBr3:Ce detectors was used for the first time. A study of the in-beam performances of such array was carried out, together with a characterization of large volume LaBr3:Ce detectors.