Magnesium suppression for 26Al measurements using AlO-ions

Measuring the resonance strengths of the 25Mg(p,γ)26Al reaction at energies of astrophysical interest poses a very difficult task for the usual prompt γ-ray detection method. Here we describe an alternative method in which targets are first irradiated and the produced 26Al nuclei are off-line counted by means of AMS. An overall efficiency of 4 × 10−5 could be achieved extracting AlO− from the ion source. For this purpose, a careful chemical treatment of the samples and the use of a gas filled magnet were necessary.