Revised decay properties of the key 93-keV resonance in the Mg-25(p,gamma) reaction and its influence on the MgAl cycle in astrophysical environments

The gamma-decay properties of an excited state in Al-26 at 6398.3(8) keV have been reexamined using the B-11 + O-1(6) fusion-evaporation reaction. This level represents a key 93.1(8)-keV resonance in the Mg-25 +p system and its relative branching to the Al-26 ground state, f(0), has been determined to be 0.76 +/- 0.03 (stat.) +/- 0.10 (syst.). This is a significantly higher value than the most recent evaluation and implies a considerable increase in the production of cosmic gamma rays from Al-26 radioactivity.