Speaker
Description
The reaction dynamics induced by light weakly-bound nuclei at energies around the Coulomb barrier has been a puzzle for many years. Compared to reactions induced by stable well-bound nuclei, these projectiles trigger a larger variety of nuclear processes while approaching a target nucleus. Being very weakly-bound, they can more easily breakup in the target Coulomb and nuclear field. At the same time, having usually a well-pronounced cluster structure, they could more likely transfer one of the fragments to the target. In turn, also the fusion process is strongly influenced by the unusually large cross sections for direct processes.
Within thin framework, we investigated in two experiments performed with the Radioactive Ion Beam facilities EXOTIC at INFN-LNL (Italy) and CRIB at RIKEN (Japan) the reaction dynamics induced by 7Be and 8B, respectively, on a 20Pb target at energies around the Coulomb barrier. In particular, we measured for the first time the elastic scattering process and the angular distributions for the production of projectile fragments. In the case of the 7Be+20Pb reaction, we observed also a few tens of He-He, He-3He and He-2H coincidences, clear fingerprints of a n-pickup, exclusive breakup and p-stripping mechanism, respectively. However, the largest majority (> 97%) of 3He and He ions were detected as singles events.
The recent upgrade of the facility EXOTIC, which has been coupled to the gamma-ray tracking spectrometer AGATA, should allow to perform particle-gamma coincidences between 7Be fragments and the Po isotopes produced after the 3He/He-stripping process and to shed some light on the reaction mechanisms underlying the 3He and He production. The work done for the upgrade of the facility, the connection to AGATA and the perspectives to perform particle-gamma correlation measurements for the system 7Be+20Pb will be eventually presented.