In-beam measurements of 13C+12C fusion reaction cross section at energies around and below Coulomb barrier

Abstract

The reaction cross section of the 12C+12C system is difficult to measure because of the presence of the resonances in the Gamow energy window. It has been proved that the 13C+12C reaction is a good alternative to study the behavior of the reaction cross section at energies relevant for astrophysics. We have measured it with activation and online techniques. During online measurements we were interested to determine the relative contributions of the open channels of the 13C+12C reaction. These determinations are necessary to evaluate the total fusion reaction cross section. Therefore, we have measured the γ-ray yields of proton, neutron and alpha particle evaporation channels from the resulting 25Mg compound nucleus using prompt γ-rays measurements. This complements the activation method. The irradiations took place at the 3 MV Tandetron Accelerator at IFIN-HH [1], Bucharest and the prompt gamma-rays were measured using a hyper-pure germanium detector with 100% relative efficiency, shielded with lead bricks. The energy range for the irradiation was from 4.6 up to 11 MeV (in laboratory frame), in steps of 0.2 MeV and the online measurements were performed from 6.4 up to 11 MeV.