Constraint on the astrophysical Ne18(α,p)Na21 reaction rate through a Mg24(p,t)Mg22 measurement

K. Y. Chae, The University of Tennessee, Knoxville
D. W. Bardayan, ORNL Physics Division
J. C. Blackmon, ORNL Physics Division
K. A. Chipps, Colorado School of Mines
R. Hatarik, Rutgers University–New Brunswick
K. L. Jones, The University of Tennessee, Knoxville
R. L. Kozub, Tennessee Technological University
J. F. Liang, ORNL Physics Division
C. Matei, Oak Ridge Associated Universities
B. H. Moazen, The University of Tennessee, Knoxville
C. D. Nesaraja, The University of Tennessee, Knoxville
P. D. O'Malley, Rutgers University–New Brunswick
S. D. Pain, Rutgers University–New Brunswick
S. T. Pittman, The University of Tennessee, Knoxville
M. S. Smith, ORNL Physics Division


The Ne18(α,p)Na21 reaction plays a crucial role in the (α,p) process, which leads to the rapid proton capture process in x-ray bursts. The reaction rate depends upon properties of Mg22 levels above the α threshold at 8.14 MeV. Despite recent studies of these levels, only the excitation energies are known for most with no constraints on the spins. We have studied the Mg24(p,t)Mg22 reaction at the Oak Ridge National Laboratory (ORNL) Holifield Radioactive Ion Beam Facility (HRIBF), and by measuring the angular distributions of outgoing tritons, we provide some of the first experimental constraints on the spins of astrophysically important Ne18(α,p)Na21 resonances. © 2009 The American Physical Society.