Measurement of F 17 ( d , n ) Ne 18 and the impact on the F 17 ( p , γ ) Ne 18 reaction rate for astrophysics

Background: The F-17(p, gamma)Ne-18 reaction is part of the astrophysical "hot CNO" cycles that are important in astrophysical environments like novas. Its thermal reaction rate is low owing to the relatively high energy of the resonances and therefore is dominated by direct, nonresonant capture in stellar environments at temperatures below 0.4 GK. Purpose: An experimental method is established to extract the proton strength to bound and unbound states in experiments with radioactive ion beams and to determine the parameters of direct and resonant capture in the F-17(p, gamma)Ne-18 reaction. Method: The F-17(d, n)Ne-18 reaction is measured in inverse kinematics using a beam of the short-lived isotope F-17 and a compact setup of neutron, proton, gamma-ray, and heavy-ion detectors called RESONEUT. Results: The spectroscopic factors for the lowest l = 0 proton resonances at E-c.m. = 0.60 and 1.17 MeV are determined, yielding results consistent within 1.4 sigma of previous proton elastic-scattering measurements. The asymptotic normalization coefficients of the bound 2(1)(+) and 2(2)(+) states in Ne-18 are determined and the resulting direct-capture reaction rates are extracted. Conclusions: The direct-capture component of the F-17(p, gamma)Ne-18 reaction is determined for the first time from experimental data on Ne-18.