Measurement of Radiative Proton Capture on 18F and Implications for Oxygen-Neon Novae

GammaNovaePPeer ReviewedScience
The rate of the 18F(p,g)19Ne reaction affects the final abundance of the gamma-ray observable radioisotope 18F, produced in novae. However, no successful measurement of this reaction exists and the rate used is
calculated from incomplete information on the contributing resonances. Of the two resonances thought to
play a significant role, one has a radiative width estimated from the assumed analogue state in the mirror
nucleus, 19F. The second does not have an analogue state assignment at all, resulting in an arbitrary
radiative width being assumed. Here, we report the first successful direct measurement of the
18F(p,g)19Ne reaction. The strength of the 665 keV resonance (Ex = 7.076 MeV) is found to be over
an order of magnitude weaker than currently assumed in nova models. Reaction rate calculations show
that this resonance therefore plays no significant role in the destruction of 18F at any astrophysical
Author: C. Akers
Journal: Phys. Rev. C