Measurement of (α,n) reaction cross sections of erbium isotopes for testing astrophysical rate predictions
Kiss, G. G.
The γ-process in core-collapse and/or type Ia supernova explosions is thought to explain the origin of the majority of the so-called p nuclei (the 35 proton-rich isotopes between Se and Hg). Reaction rates for γ-process reaction network studies have to be predicted using Hauser-Feshbach statistical model calculations. Recent investigations have shown problems in the prediction of α-widths at astrophysical energies which are an essential input for the statistical model. It has an impact on the reliability of abundance predictions in the upper mass range of the p nuclei. With the measurement of the <sup>164,166</sup>Er(α,n)<sup>167,169</sup>Yb reaction cross sections at energies close to the astrophysically relevant energy range we tested the recently suggested low energy modification of the α+nucleus optical potential in a mass region where γ-process calculations exhibit an underproduction of the p nuclei. Using the same optical potential for the α-width which was derived from combined <sup>162</sup>Er(α,n) and <sup>162</sup>Er(α,γ) measurement makes it plausible that a low-energy modification of the optical α+nucleus potential is needed.