Alpha induced reaction cross section measurements on 162Er for the astrophysical γ process

The cross sections of the 162Er(α,γ)166Yband 162Er(α,n)165Ybreactions have been measured for the first time. The radiative alpha capture reaction cross section was measured from Ec.m.=16.09MeV down to Ec.m.=11.21MeV, close to the astrophysically relevant region (which lies between 7.8 and 11.48MeV at 3GK stellar temperature). The 162Er(α,n)165Yb reaction was studied above the reaction threshold between Ec.m.=12.19 and 16.09MeV. The fact that the 162Er(α,γ)166Ybcross sections were measured below the (α,n)threshold at first time in this mass region opens the opportunity to study directly the α-widths required for the determination of astrophysical reaction rates. The data clearly show that compound nucleus formation in this reaction proceeds differently than previously predicted