Neutron capture inTe122,123,124: Critical test forsprocess studies

Abstract

The neutron capture cross sections of $^{122,123,124,125,126}\mathrm{Te}$ were measured in the energy range from 10 to 200 keV at the Karlsruhe Van de Graaff accelerator using gold as a standard. Neutrons were produced via the $^{7}\mathrm{Li}$(p,n${)}^{7}$Be reaction by bombarding metallic Li targets with a pulsed proton beam. Capture events were registered with the Karlsruhe 4\ensuremath{\pi} barium fluoride detector. Several sets of measurements were performed under different experimental conditions to study the systematic uncertainties in detail. The cross section ratios \ensuremath{\sigma}(Te)/\ensuremath{\sigma}(Au) were determined with an overall uncertainty of \ensuremath{\sim}1%. This is an improvement by about a factor of 5 compared to existing data. Maxwellian-averaged neutron capture cross sections were calculated for thermal energies between kT=10 and 100 keV by normalizing the cross section shape up to 600 keV neutron energy reported in literature to the present data. These stellar cross sections were used in an s process analysis. With the classical approach the abundances of the three s only isotopes $^{122,123,124}\mathrm{Te}$ could be reproduced within the experimental uncertainties of \ensuremath{\sim}1%. The accuracy of the present data also allowed us to derive constraints for the existing stellar models with respect to the effective neutron density. Furthermore, the p process abundances for the tellurium isotopes are discussed.