No abstract

The prompt γ -ray emission is investigated in the 16 A MeV energy region by means of the 36,40Ar + 96,92Zr fusion reactions leading to a compound nucleus in the vicinity of 132Ce. The dynamical nature\ud of this radiation is confirmed. We show that the prompt γ radiation has an angular distribution pattern\ud consistent with a dipole oscillation along the symmetry axis of the dinuclear system. The data are\ud compared with calculations based on a collective bremsstrahlung analysis of the reaction dynamics

High-energy γ rays and light charged particles from the 36Ar + 96Zr and 40Ar + 92Zr reactions at Elab = 16\ud and 15.1 MeV/nucleon, respectively, were measured in coincidence with evaporation residues by means of the\ud MEDEA multidetector array coupled to four parallel plate avalanche counters. The aim of this experiment was to\ud investigate the prompt γ radiation, emitted in the decay of the dynamical dipole mode, in the about 16 MeV/nucleon\ud energy range and to map its beam energy dependence, comparing the present results with our previous ones\ud obtained at lower energies. The studied reactions populate, through entrance channels having different charge\ud asymmetries, a compound nucleus in the region of Ce under the same conditions of excitation energy and spin.\ud Light charged particle energy spectra were used to pin down the average excitation energy and the average mass\ud of the system. By studying the γ -ray spectra of the charge symmetric reaction 40Ar + 92Zr, the statistical giant\ud dipole resonance (GDR) parameters and angular distribution were extracted, and a comparison of the linearized\ud 90◦γ -ray spectra of the two reactions revealed a 12% extra yield in the GDR energy region for the more charge\ud asymmetric system. The center-of-mass angular distribution data of this extra γ yield, compatible with a dipole\ud oscillating along the symmetry axis of the dinuclear system, support its dynamical nature. The experimental\ud findings are compared with theoretical predictions performed within a Boltzmann-Nordheim-Vlasov transport\ud model and based on a collective bremsstrahlung analysis of the entrance channel reaction dynamics.An interesting\ud sensitivity to the symmetry term of the equation of state and to in-medium effects on nucleon-nucleon (nn) cross\ud sections is finally discussed

The Trojan Horse Method (THM) represents the indirect way to measure reactions between charged particles at astrophysical energies. This is done by measuring the quasi free cross section of a suitable three body process. The basic features of the THM will be presented together with some applications to demonstrate its practical use.