UC Berkeley

The carbon burning nuclear reactions 12C(12C, alpha)20Ne, 12C(12C,p)23Na, and 12C(12C,n)23Mg occur during the carbon burning phase of sufficiently large stars and during explosive events such as supernovae. The Gamow window for these reactions is typically around 1.5 MeV, however direct measurements at energies in this range are very difficult due to the large Coulomb barrier between the carbon atoms. The compound nucleus formed during these reactions is 24Mg. For energies around the Gamow window this compound nucleus has an excitation energy of 15 to 16 MeV. A surrogate experiment which produces the compound nucleus can measure the branching ratios for the excited compound nucleus and thus the ratios between the carbon burning reaction cross sections. An experiment was performed using inelastic scattering of 40 MeV alpha particles to produce 24Mg excited up to 27 MeV and the applicability of these results as a surrogate for the carbon burning reactions is examined. A successful surrogate measurement, which this experiment partially achieves, will both provide the branching ratios within the Gamow window and aid future direct measurements of carbon burning within the Gamow window.