Re-evaluation of the ¹⁶O(n,γ)¹⁷O cross section at astrophysical energies and its role as neutron poison in the s process

الأصل · EN

The doubly-magic nucleus ¹⁶O has a small neutron capture cross section of just a few tens of microbarn in the astrophysical energy region. Despite of this, ¹⁶O plays an important role as neutron poison in the astrophysical slow neutron capture (s) process due to its high abundance. We present in this paper a re-evaluation of the available experimental data for ¹⁶O(n,γ)¹⁷O and derive a new recommendation for the Maxwellian-averaged cross sections (MACS) between kT= 5-100 keV. Our new recommendations are lower up to kT= 60 keV compared to the previously recommended values but up to 14% higher at kT= 100 keV. We explore the impact of this different energy dependence on the weak s-process during core helium- (kT= 26 keV) and shell carbon burning (kT= 90 keV) in massive stars where ¹⁶O is the most abundant isotope.