The total cross section of the 12 C+ 16 O fusion reaction has been measured at low energies to investigate the role of this reaction during late stellar evolution burning phases. A high-intensity oxygen beam, produced by the 5MV pelletron accelerator at the University of Notre Dame, impinged on a thick, ultra-pure graphite target. Protons and γ-rays were simultaneously measured in the center-of-mass energy range from 3.64 to 5.01 MeV for singles and from 3.73 to 4.84 MeV for coincidence events, using silicon and Ge detectors. Statistical model calculations were employed to interpret the experimental results. The emergence of a new resonance like broad structure and a decreasing trend in the S-factor data towards lower energies (opposite to previous data) are found for the 12 C+ 16 O fusion reaction. Based on these results the uncertainty range of the reaction rate within the temperature range of late stellar burning environments is being discussed .

Radiative alpha-capture, (α, γ), reactions play a critical role in nucleosynthesis and nuclear energy generation in a variety of astrophysical environments. The St. George recoil separator at the University of Notre Dame's Nuclear Science Laboratory was developed to measure (α, γ) reactions in inverse kinematics via recoil detection in order to obtain nuclear reaction cross sections at the low energies of astrophysical interest, while avoiding the γ-background that plagues traditional measurement techniques. Due to the γ ray produced by the nuclear reaction at the target location, recoil nuclei are produced with a variety of energies and angles, all of which must be accepted by St. George in order to accurately determine the reaction cross section. We demonstrate the energy acceptance of the St. George recoil separator using primary beams of helium, hydrogen, neon, and oxygen, spanning the magnetic and electric rigidity phase space populated by recoils of anticipated (α, γ) reaction measurements. We find the performance of St. George meets the design specifications, demonstrating its suitability for (α, γ) reaction measurements of astrophysical interest.