Direct Measurement of the O-14(alpha, alpha)O-14 Cross Section for Astrophysically Important O-14 + alpha Resonances

Abstract

For the study of astrophysically important states in Ne-18, the O-14(alpha, alpha)O-14 cross section was measured in inverse kinematics using a radioactive O-14 beam. This reaction was investigated for properties of resonant states of Ne-18 for determining the O-14(alpha, p)F-17 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 O-14 was performed using the low-energy radioactive ion (RI) beam separator at the Center for Nuclear Study (CNS) in the RIKEN Accelerator Research Facility. The energy range E-x = 7.2 similar to 13.1 MeV of Ne-18 was scanned with the thick target method. Recoiled alpha particles were measured with Si dE-E telescopes. Spins and widths of three resonances at E-x = 8.6, 9.22, and 10.06 MeV were calculated using the R-matrix analysis, and a new state of Ne-18 at E-x = 12.0 MeV was found in this experiment