Absolute cross sections measurement for the 12C+12C system at astrophysically relevant energies

The C-12 + C-12 fusion reaction has been studied in the center-of-mass energy range of 2.25 to 6.01 Mev. Through the detection of gamma rays from the first excited states of the residual nuclei Ne-20, Na-23 and Mg-23, absolute cross sections for the C-12(C-12, alpha), C-12(C-12, p) and C-12(C-12, n) reactions have been obtained. In this new measurement, the energy dependence of the S-factor is found to increase as the energy decreases below 3 MeV in the center of mass. This tendency was observed in previous measurements by Mazarakis et al., and has since then become a subject of controversy. In this work, where the cross sections are measured at even lower energies, we confirm the rise in the S-factor toward the energy region relevant for star evolution and nucleosynthesis calculations (E-c.m. = 1-3 MeV). (c) 2006 Elsevier B.V. All rights reserved.