Abstract
The neutron capture cross sections of have been determined relative to that of gold by means of the activation method. The samples were irradiated in a quasistellar neutron spectrum for kT=25 keV using the (p,nBe reaction near threshold. Variation of the experimental conditions in different activations and the use of different samples allowed for the reliable determination of corrections and the evaluation of systematic uncertainties. The resulting stellar cross sections can be given with uncertainties around 6%, which represents a considerable improvement compared to previous measurements. These data are complemented by a new set of calculated cross sections for the unstable isotopes , , and , which act as branching points in the s-process path. Based on these results, the s-process flow in the Nd-Pm-Sm region is discussed with respect to the neutron density during stellar helium burning and to isotopic anomalies in meteorites. The updated s-abundances are also used for a discussion of r- and p-process residuals.
- Received 28 September 1994
DOI:https://doi.org/10.1103/PhysRevC.51.1540
©1995 American Physical Society