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

D. W. Bardayan, ORNL Physics Division
J. C. Blackmon, ORNL Physics Division
W. Bradfield-Smith, Yale University
C. R. Brune, The University of North Carolina at Chapel Hill
A. E. Champagne, The University of North Carolina at Chapel Hill
T. Davinson, The University of Edinburgh
B. A. Johnson, Tennessee Technological University
R. L. Kozub, Tennessee Technological University
C. S. Lee, Chung-Ang University
R. Lewis, Yale University
P. D. Parker, Yale University
A. C. Shorter, The University of Edinburgh
M. S. Smith, ORNL Physics Division
D. W. Visser, Yale University
P. J. Woods, The University of Edinburgh


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.