The E1 capture amplitude in C-12 (alpha,gamma(0))O-16

An excitation function of the ground-state gamma (0)-ray capture transition in C-12(alpha, gamma)O-16 at theta (gamma) = 90 degrees was obtained in fa r geometry using six Ge detectors, where the study of the reaction was init iated in inverse kinematics involving a windowless gas target. The detector s observed predominantly the El capture amplitude. The data at E = 1.32 to 2.99 MeV lead to an extrapolated astrophysical S factor S-E1(E-0) = 90 +/- 15 keV b at E-0 = 0.3 MeV (for the case of constructive interference betwee n the two lowest E1 sources), in good agreement with previous works. Howeve r, a novel Monte Carlo approach in the data extrapolation reveals systemati c differences between the various data sets such that a combined analysis o f all available data sets could produce a biased estimate of the S-E1(E-0) value. As a consequence, the case of destructive interference between the t wo lowest E1 sources with S-E1(E-0) = 8 +/- 3 keV b cannot be ruled out rig orously.