Measurement of the ³⁰S+α system for type I X-ray bursts

The ³⁰S(α, p) reaction is considered to be important in the nuclear trajectory to higher mass in type I X-ray bursts. The reaction flow encounters a bottle-neck at ³⁰S, owing to the competition of photo-disintegration with further proton capture, and because the half-life of this isotope is on the order of the burst rise timescale. Different burst simulations by various researchers indicate the (α,p) reaction may by-pass this waiting point, depending on the stellar reaction rate, which has not previously been measured experimentally, and the structure of the compound nucleus ³⁴Ar is not well understood above the alpha-threshold. The ³⁰S(α, p) reaction could explain rare bolometrically double-peaked burst profiles, appears to make a considerable contribution to the overall energy generation, and affects the neutron star crustal composition for the recurrent inertia required in burst models to reproduce astronomical observations. Using a low-energy ³⁰S radioactive ion beam and an active target technique (a helium gas mixture serves as both a target gas and a detector fill gas), we acquired data on both alpha elastic scattering of ³⁰S as well as the ³⁰S(α, p) reaction simultaneously at relevant energies for X-ray bursts. We present for the first time the status of the data analysis and the preliminary results of this research.