Measurement of the Se 77 (n,?) cross section up to 200 keV at the n_TOF facility at CERN

The 77 Se(n, ? ) reaction is of importance for 77 Se abundance during the slow neutron capture process in massive stars. We have performed a new measurement of the 77 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 77 Se abundances produced through the slow neutron capture process in selected stellar models of 15M and 2M, respectively, compared to using previous recommendation of the cross section.