Observation of the astrophysically important 3⁺ state in ¹⁸Ne via elastic scattering of a radioactive ¹⁷F beam from ¹H

D. W. Bardayan, ORNL Physics Division
J. C. Blackmon, ORNL Physics Division
C. R. Brune, The University of North Carolina at Chapel Hill
A. E. Champagne, The University of North Carolina at Chapel Hill
A. A. Chen, The University of North Carolina at Chapel Hill
J. M. Cox, Tennessee Technological University
T. Davinson, The University of Edinburgh
V. Y. Hansper, ORNL Physics Division
M. A. Hofstee, Colorado School of Mines
B. A. Johnson, Tennessee Technological University
R. L. Kozub, Tennessee Technological University
Z. Ma, ORNL Physics Division
P. D. Parker, Yale University
D. E. Pierce, ORNL Physics Division
M. T. Rabban, ORNL Physics Division
A. C. Shotter, The University of Edinburgh
M. S. Smith, ORNL Physics Division
K. B. Swartz, Yale University
D. W. Visser, Yale University
P. J. Woods, Colorado School of Mines

Abstract

The 17F(p, γ)18 reaction is important in stellar explosions, but its rate has been uncertain because of an expected 3+ state in 18Ne that has never been conclusively observed. This state would provide a strong l = 0 resonance and, depending on its excitation energy, could dominate the stellar reaction rate. We have observed this missing 3+ state by measuring the 1H(17F, p)17F excitation function with a radioactive 17F beam at the ORNL Holifield Radioactive Ion Beam Facility. We find that the state lies at a center-of-mass energy of Er = 599.8 ± 1.5stat ± 2.0sys keV (Ex = 4523.7 ± 2.9keV) and has a width of Γ = 18 ± 2stat ± 1sys keV. © 1999 The American Physical Society.