Kinematically complete measurement of the 1H(18F,p)18F excitation function for the astrophysically important 7.08-MeV state in 19Ne

Abstract

Knowledge of the astrophysical 18F(p,α)15O rate is important for understanding gamma-ray emission from novae and heavy-element production in x-ray bursts. A state with Ex≃7.08 MeV in 19Ne provides an s-wave resonance and, depending on its properties, could dominate the 18F(p,α)15O rate. By measuring a kinematically complete 1H(18F,p)18F excitation function with a radioactive 18F beam at the ORNL Holifield Radioactive Ion Beam Facility, we find that the 19Ne state lies at a center-of-mass energy of 665.3±1.7 keV (Ex =7077±2 keV), has a total width of 38.5±3.4 keV, and a proton partial-width of 15.8±1.6 keV.