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

TL;DR

This study reports the first measurements of alpha-induced reaction cross sections on 162Er near astrophysical energies, revealing new insights into reaction mechanisms relevant for stellar nucleosynthesis.

Contribution

It provides the first experimental cross section data for 162Er reactions, enabling improved modeling of astrophysical gamma process reactions.

Findings

Measured (α,γ) and (α,n) cross sections near astrophysical energies.

Observed differences in compound nucleus formation compared to predictions.

Opened new possibilities for studying alpha-widths in this mass region.

Abstract

The cross sections of the 162Er(a,g,)166Yb and 162Er(a,n)165Yb reactions have been measured for the first time. The radiative alpha capture reaction cross section was measured from Ec.m. = 16.09 down to Ec.m. = 11.21 MeV, close to the astrophysically relevant region (which lies between 7.8 and 11.48 MeV at 3 GK stellar temperature). The 162Er(a,n)165Yb reaction was studied above the reaction threshold between Ec.m. = 12.19 and 16.09 MeV. The fact that the 162Er(a,g)166Yb cross sections were measured below the (a,n) threshold at first time in this mass region opens the opportunity to study directly the a-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.