Absolute cross section of the 3He(α,γ)7Be reaction

The absolute cross section σ(E) of the 3He(α,γ)7Be reaction has been measured from Ec.m=195 to 686 keV. The studies employed both a supersonic jet gas target and an extended gas target, and were carried out by the observation of the prompt capture γ-ray transitions as well as the 7Be residual nuclei. The absolute cross sections deduced from the capture γ-rays are in good agreement with most previous work and remove a discrepancy with other earlier work. In comparison, the σ(E) values obtained from the 7Be residual nuclei are systematically higher, suggesting a small production of additional 7Be by contaminant reactions. (orig.)