Measurement of the Se(n,) cross section up to 200 keV at the n_TOF facility at CERN

Sosnin, N. V.*; Harada, Hideo   ; Kimura, Atsushi   ; 128 of others*

The Se(n,) reaction is of importance for Se abundance during the slow neutron capture process in massive stars. We have performed a new measurement of the Se radiative neutron capture cross section at the Neutron Time-of-Flight facility at CERN. Resonance capture kernels were derived up to 51 keV and cross sections up to 200 keV. Maxwellian-averaged cross sections were calculated for stellar temperatures between kT = 5 keV and kT = 100 keV, with uncertainties between 4.2% and 5.7%. Our results lead to substantial decreases of 14% and 19% in Se abundances produced through the slow neutron capture process in selected stellar models, compared to using previous recommendation of the cross section.