Experimental determination of the 26Al(n,α)23Na reaction cross section and calculation of the Maxwellian averaged cross section at stellar temperatures

The Al-26(n,alpha)Na-23 reaction cross section has been studied at the linear accelerator GELINA of the Institute for Reference Materials and Measurements in Geel, Belgium, and has been determined up to a neutron energy of about 100 keV using the time-of-flight technique. Six resonances could be observed in this energy region, whereas before only one had been identified experimentally. For four of them, resonance parameters such as resonance energy, total width, area, and spin of the state could be determined. From the obtained Al-26(n,alpha)Na-23 cross section data, Maxwellian averaged cross section (MACS) values were calculated by numerical integration. Since neutron induced reactions are among the major destruction mechanisms of Al-26 in our Galaxy, these new MACS values contribute to a better understanding of the observed Al-26 abundance.