Si Total Cross Section*

The observation of gamma rays from the decay of ²⁶Al provides direct evidence of ongoing nucleosynthesis in the galaxy. While the observed distribution of ²⁶Al points to massive stars as the main production site, the underlying nuclear processes are uncertain. Two reactions contributing to the uncertainty of ²⁶Al production are the ²⁵Mg(α,n)²⁸Si and ²⁶Mg(α,n)²⁹Si reactions. While previous measurements have been made, discrepant data has led to uncertainties in the reaction rates of 59% and 29% (for ²⁵Mg and ²⁶Mg respectively) for C/Ne burning in massive stars. To resolve these uncertainties, a measurement of the ^25,26Mg(α,n)^28.29Si total cross section was performed with a new Active Target Detector at The University of Notre Dame’s Nuclear Science Lab. Results of this measurement will be discussed.