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

¹ Instituto de Estructura de la Materia, CISC, Serrano 113bis, E-28006 Madrid, Spain
² Grupo de Física Nuclear, Facultad de CC. Físicas, Universidad Complutense de Madrid, CEI Moncloa, 28040 Madrid, Spain
³ Department of Physics and Astronomy, University of Aarhus, DK-8000, Aarhus, Denmark

^* e-mail: vicente.garcia@csic.es

Published online: 8 December 2023

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.