Absolute resonance strengths in the 6,7Li(alpha,gamma)10,11B reactions

The absolute strengths of the Ea=1175keV resonance in the 6Li(a,g)10B reaction and of the Ea=814 keV resonance in the 7Li(a,g)11B reaction have been measured to $\omega\gamma$=366+-38 meV and $\omega\gamma$=300+-32 meV, respectively, in good agreement with previous values. These resonances can be used to measure the absolute acceptance of the recoil separator ERNA to a precision of about 10%.Comment: 6 pages, 5 figures, to appear in European Physical Journal