%0 Journal Article %T Measurement of (alpha,n) reaction cross sections of erbium isotopes for testing astrophysical rate predictions %A G. G Kiss %A T. Sz¨¹cs %A T. Rauscher %A Zs T£¿r£¿k %A L. Csedreki %A Zs F¨¹l£¿p %A Gy Gy¨¹rky %A Z. Hal¨¢sz %J Physics %D 2015 %I arXiv %R 10.1088/0954-3899/42/5/055103 %X The $\gamma$-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 $\gamma$-process reaction network studies have to be predicted using Hauser-Feshbach statistical model calculations. Recent investigations have shown problems in the prediction of $\alpha$-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 $^{164,166}$Er($\alpha$,n)$^{167,169}$Yb reaction cross sections at energies close to the astrophysically relevant energy range we tested the recently suggested low energy modification of the $\alpha$+nucleus optical potential in a mass region where $\gamma$-process calculations exhibit an underproduction of the $p$ nuclei. Using the same optical potential for the $\alpha$-width which was derived from combined $^{162}$Er($\alpha$,n) and $^{162}$Er($\alpha$,$\gamma$) measurement makes it plausible that a low-energy modification of the optical $\alpha$+nucleus potential is needed. %U http://arxiv.org/abs/1503.01853v1