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

The 77 Se ( n , γ ) 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 k T = 5 keV and k T = 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 15 M ⊙ and 2 M ⊙ , respectively, compared to using previous recommendation of the cross section.UK Science and Facilities Council (ST/M006085/1)MSMT of the Czech RepublicThe Charles University UNCE/SCI/013 projectEuropean Research Council ERC-2015-StG No. 67749