Measurement of light charged particles in the decay channels of medium-mass excited compound nuclei
Résumé
The 48Ti on 40Ca reactions have been studied at 300 and 600 MeV using the Tandem-ALPI accelerator complex at Laboratori Nazionali di Legnaro. The reactions have been analyzed focusing on the fusion-evaporation (FE) and fusion-fission (FF) exit channels, which dominates in symmetric entrance channel collision at moderate bombarding energies. In particular, the energy spectra, angular distributions, and multiplicities of the emitted light charged particles in the two reaction channels FE and FF will be discussed. An estimation of the absolute cross sections for both channels will be also given. The experimental results will be then compared to Monte Carlo simulations based on the statistical model. The comparison between the results obtained from the same system populated at two excitation energies is important to evidence the possible growing of non-equilibrium effects. At the lower energy complete fusion is expected to exhaust almost the whole central collision cross section, with a consequent negligible non-equilibrium emission. This reaction may therefore be used to keep under control the statistical code parameters. Results on the comparison between the two reactions energies will be discussed. Indeed, very few data exist in literature which are coming from coincidence measurements between evaporation residues and light charged particles for compound nuclei with mass A < 150. That is why statistical model parameters are not completely tested in this mass region. The present work, which deals with the de-excitation of 88Mo, is therefore very interesting because experimental results will help in refining the statistical description of the decay of hot and rotating nuclei with moderate size.