Direct measurement of the14O(α, α)14O cross section for astrophysically important 14O + α resonances

Abstract

For the study of astrophysically important states in 18Ne, the 140(α, a)140 cross section was measured in inverse kinematics using a radioactive 14O beam. This reaction was investigated for properties of resonant states of 18Ne for determining the 14O(α,p)17F reaction rate, which is one of the most important reactions for understanding the breakout mechanism from the Hot CNO cycle to the rp-process. Alpha-induced elastic scattering on 14O was performed using the lowenergy radioactive ion (RI) beam separator at the Center for Nuclear Study (CNS) in the RIKEN Accelerator Research Facility. The energy range Ex = 7.2-13.1 MeV of 18Ne was scanned with the thick target method. Recoiled alpha particles were measured with Si dE-E telescopes. Spins and widths of three resonances at Ex = 8.6, 9.22, and 10.06 MeV were calculated using the R-matrix analysis, and a new state of 18Ne at Ex = 12.0 MeV was found in this experiment.