Studying X-ray burst nucleosynthesis in the laboratory

Type I X-ray bursts are the most common explosions in the Galaxy; however, the nucleosynthesis that occurs during the thermonuclear runaway and explosion is poorly understood. In this proceedings we discuss current experimental efforts and techniques that are being used to study X-ray burst nucleosynthesis in the laboratory. Specifically, radioactive ion beam techniques that have recently been developed have allowed the study of some of the most important (α, p) reactions in X-ray bursts for the first time. © Published under licence by IOP Publishing Ltd

Radioactive ion beam studies of α, p process waiting points in X-Ray Bursts

The nucleosynthetic flow in type I X-ray Bursts (XRBs) is driven by the triple-α, rp and α,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 a (p, γ)-(γ, p) equilibrium and must await β decay unless the (α, p) reaction is fast enough to break out of the waiting point first. A method to study these αp-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. These time-inverse reactions have been used to study all four of the α, p process waiting points via the p(25Al,22Mg)α, p(33Cl,30S)α, and p(37K, 34Ar)α reactions. The data from these studies have been used to determine rates for 22Mg(α, p)25Al, 26Si(α, p)29P, 30S(α, p) 33Cl, and 34Ar(α, p)37K and have also been compared with theoretical calculations. The results and possible implications for nucleosynthesis in XRBs will be discussed. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence