Populating α-unbound states in 16O via 19F (p, αy)16O reaction

Abstract

The 12C(α, y)16O reaction is important in the production of universal 16O, but its cross-section at the relevant energies of static helium burning is complex and uncertain. The total cross-section originates from a sum of resonance tails and direct captures, making the contributions of sub-threshold states difficult to estimate. One proposed method to estimate these contributions involves determining relevant reduced α-widths of the sub-threshold states through indirect measurements. Therefore, 19F(p, αy)16O reaction was used to populate α-unbound states in 16O using a 2.6 MeV proton beam on a CaF2 target. A detection system consisting of single and telescope configurations of Si detectors was used to detect 2α-particles and a 12C particle in coincidence. Scintillator detectors were included in the setup to study the de-excitation of the states populated in 16O to the ground state. Under good event conditions a preliminar indentification of the particles detected has been conducted.