Studying the alpha p-process waiting points using Radioactive Ion Beams

C. M. DEIBEL; M. ALCORTA; P. BERTONE; J. A. CLARK; C. R. HOFFMAN; C. L. JIANG; B. P. KAY; H. Y. LEE; R. C. PARDO; K. E. REHM; A. ROGERS; J. M. FIGUEIRA; S. BEDOOR; D. SHETTY; A. H. WUOSMAA; J. C. LIGHTHALL; S. T. MARLEY; M. PAUL; C. UGALDE

East Lansing, Michigan

Encuentro; 2011 Fall Meeting of the APS Division of Nuclear Physics; 2011

American Physical Society

The nucleosynthetic flow in type I X-ray Bursts (XRBs) is driven by the triple-alpha, rp and alpha-p processes. Several intermediate mass nuclei, 22Mg, 26Si, 30S, and 34Ar, have been identified as possible candidates for waiting points in XRBs. When such a nucleus is reached, the flow stalls due to (p, gamma)-(gamma, p) equilibrium and must await beta decay unless the (alpha, p) reaction is fast enough to break out of the waiting point first. A method to study these alpha p-process reactions has been developed whereby the time-inverse reaction is studied in inverse kinematics using radioactive ion beams produced by the in-flight method at the Argonne National Laboratory ATLAS facility. The reactions p(29P,26Si)alpha, p(33Cl,30S)alpha, and p(37K,34Ar)alpha have been studied to determine reaction rates for 26Si(alpha, p)29P, 30S(alpha, p)33Cl, and 34Ar(alpha, p)37K, respectively. The results and possible implications for nucleosynthesis in XRBs will be discussed.