First direct measurement of resonance strengths in 17O(α, γ)21Ne

The reaction O-17(alpha, gamma)Ne-21 has been measured by in-beam gamma spectroscopy for the first time in the energy range E-alpha = 750-1650 keV using highly enriched anodized Ta-2(O-17)(5) targets. Resonances were found at E-alpha = 1002, 1386, and 1619 keV. Their strengths and primary gamma-ray branchings are given. The new results exclude the low reaction rate of Descouvemont and support the rate of Caughlan and Fowler. Implications for the neutron poisoning efficiency of O-16 in the weak s-process are discussed.