High precision Y89(α,α)Y89 scattering at low energies

Abstract

Elastic scattering cross sections of the Y89(α,α)Y89 reaction have been measured at energies Ec.m.=15.51 and 18.63 MeV. The high-precision data for the semimagic N=50 nucleus Y89 are used to derive a local potential and to evaluate the predictions of global and regional α-nucleus potentials. The variation of the elastic α-scattering cross sections along the N=50 isotonic chain is investigated by a study of the ratios of angular distributions for Y89(α,α)Y89 and Mo92(α,α)Mo92 at Ec.m. 15.51 and 18.63 MeV. This ratio is a very sensitive probe at energies close to the Coulomb barrier, where scattering data alone is usually not enough to characterize the different potentials. Furthermore, α-cluster states in Nb93=Y89 α are investigated. © 2009 The American Physical Society.