Measurement of the 78Se(n, γ)79Se cross section up to 600 keV at the n_TOF facility at CERN

Sosnin, N. V.; Lederer-Woods, C.; Garg, R.; Battino, U.; Cristallo, S.; Dietz, M.; Heinitz, S.; Krticka, M.; Reifarth, R.; Valenta, S.; Vescovi, D.; Aberle, O.; Alcayne, V.; Amaducci, S.; Andrzejewski, J.; Audouin, L.; Becares, V.; Babiano-Suarez, V.; Bacak, M.; Barbagallo, M.; Becvar, F.; Bellia, G.; Berthoumieux, E.; Billowes, J.; Bosnar, D.; Brown, A.; Busso, M.; Caamano, M.; Caballero, L.; Calvino, F.; Calviani, M.; Cano-Ott, D.; Casanovas, A.; Cerutti, F.; Chen, Y. H.; Chiaveri, E.; Colonna, N.; Cortes, G.; Cortes-Giraldo, M. A.; Cosentino, L.; Damone, L. A.; Diakaki, M.; Domingo-Pardo, C.; Dressler, R.; Dupont, E.; Duran, I.; Eleme, Z.; Fernandez-Dominguez, B.; Ferrari, A.; Finocchiaro, P.; Furman, V.; Goebel, K.; Gawlik-Ramiega, A.; Gilardoni, S.; Glodariu, T.; Goncalves, I. F.; Gonzalez-Romero, E.; Guerrero, C.; Gunsing, F.; Harada, H.; Heyse, J.; Jenkins, D. G.; Jericha, E.; Kaeppeler, F.; Kadi, Y.; Kimura, A.; Kivel, N.; Kokkoris, M.; Kopatch, Y.; Kurtulgil, D.; Ladarescu, I.; Leeb, H.; Lerendegui-Marco, J.; Lo Meo, S.; Lonsdale, S. J.; Manna, A.; Martinez, T.; Masi, A.; Massimi, C.; Mastinu, P.; Mastromarco, M.; Matteucci, F.; Maugeri, E. A.; Mazzone, A.; Mendoza, E.; Mengoni, A.; Michalopoulou, V.; Milazzo, P. M.; Murphy, A. St. J.; Musumarra, A.; Negret, A.; Nolte, R.; Ogallar, F.; Oprea, A.; Patronis, N.; Pavlik, A.; Perkowski, J.; Piersanti, L.; Porras, I.; Praena, J.; Quesada, J. M.; Radeck, D.; Ramos-Doval, D.; Rauscher, T.; Rochman, D.; Rubbia, C.; Sabate-Gilarte, M.; Saxena, A.; Schillebeeckx, P.; Schumann, D.; Smith, A. G.; Stamatopoulos, A.; Tagliente, G.; Tain, J. L.; Talip, T.; Tarifeno-Saldivia, A.; Tassan-Got, L.; Torres-Sanchez, P.; Tsinganis, A.; Ulrich, J.; Urlass, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Woods, P. J.; Wright, T.; Zugec, P.

doi:10.1103/PHYSREVC.110.065805

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.