Measurement of the Se 78 (n,γ) Se 79 cross section up to 600 keV at the n_TOF facility at CERN
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Author
n_TOF Collaboration
Sosnin, N. V.
Lederer-Woods, C.
Garg, R.
Battino, U.
Cristallo, S.
Dietz, M.
Heinitz, S.
Krtička, M.
Reifarth, R.
Valenta, S.
Vescovi, D.
Aberle, O.
Alcayne, V.
Amaducci, S.
Andrzejewski, J.
Audouin, L.
Bécares, V.
Babiano-Suarez, V.
Bacak, M.
Barbagallo, M.
Bečvář, F.
Bellia, G.
Berthoumieux, E.
Billowes, J.
Bosnar, D.
Brown, A.
Busso, M.
Caamaño, M.
Caballero, L.
Calviño, F.
Calviani, M.
Cano-Ott, D.
Casanovas, A.
Cerutti, F.
Chen, Y. H.
Chiaveri, E.
Colonna, N.
Cortés, G.
Cortés-Giraldo, M. A.
Cosentino, L.
Damone, L. A.
Diakaki, M.
Domingo-Pardo, C.
Dressler, R.
Dupont, E.
Durán, I.
Eleme, Z.
Fernández-Domínguez, B.
Ferrari, A.
Rauscher, T.
Attention
2299/28665
Abstract
The Se78(n,γ)Se79 cross section has a high impact on the abundances of Se78 produced during the slow neutron capture process (s process) in massive stars. A measurement of the Se78 radiative neutron capture cross section has been performed at the Neutron Time-of-Flight facility at CERN using a set of liquid scintillation detectors that have been optimized for a low sensitivity to neutrons. We present resonance capture kernels up to 70 keV and cross section from 70 to 600 keV. Maxwellian-averaged cross section (MACS) values were calculated for stellar temperatures between kT=5 and 100 keV, with uncertainties between 4.6% and 5.8%. The new MACS values result in substantial decreases of 20-30% of Se78 abundances produced in the s process in massive stars and AGB stars. Massive stars are now predicted to produce subsolar Se78/Se76 ratios, which is expected since Se76 is an s-only isotope, while solar Se78 abundances have also contributions from other nucleosynthesis processes.