Studying astrophysical reactions with low-energy RI beams at CRIB

Studies on nuclear astrophysics, nuclear structure, and other interests have been performed using the radioactive-isotope (RI) beams at the low-energy RI beam separator CRIB, operated by the Center for Nuclear Study (CNS) at the University of Tokyo. A typical measurement performed at CRIB is the elastic resonant scattering with the inverse kinematics. One recent experiment was on the α resonant scattering with ⁷Li and ⁷Be beams. This study is related to the astrophysical ⁷Li/⁷Be(α, γ) reactions, important at hot p-p chain and νp-process in supernovae. There have also been measurements based on other experimental methods. The first THM (Trojan Horse method) measurement using an RI beam has been performed at CRIB, to study the ¹⁸F(p, α)¹⁵O reaction at astrophysical energies via the three body reaction ²H(¹⁸F, α ¹⁵O)n. The ¹⁸F(p, α) ¹⁵O reaction rate is crucial to understand the 511-keV γ-ray production in nova explosion phenomena, and we successfully evaluated the reaction cross section at novae temperature and below experimentally for the first time. (authors)