Study of (α,p) and (α,n) reactions with a Multi-Sampling Ionization Chamber

A large number of (α,p)(α,p) and (α,n)(α,n) reactions are known to play a fundamental role in nuclear astrophysics. This work presents a novel technique to study these reactions with the active target system MUSIC whose segmented anode allows the investigation of a large energy range of the excitation function with a single beam energy. In order to verify the method, we performed direct measurements of the previously measured reactions 17O (α,n)(α,n)20Ne, 23Na (α,p)(α,p)26Mg, and 23Na (α,n)(α,n)26Al. These reactions were investigated in inverse kinematics using 4He gas in the detector to study the excitation functions in the energy range of about 2–6 MeV in the center of mass. We found good agreement between the cross sections of the 17O (α,n)(α,n)20Ne reaction measured in this work and previous measurements. Furthermore we have successfully performed a simultaneous measurement of the 23Na (α,p)(α,p)26Mg and 23Na (α,n)(α,n)26Al reactions.