Neutron spectroscopy of $^{26}$Mg states: constraining the stellar neutron source $^{22}$Ne($\alpha, n$)$^{25}$Mg

This work reports on accurate, high-resolution measurements of the 25 Mg( n,γ ) 26 Mg and 25 Mg( n,tot ) cross sections in the neutron energy range from thermal to about 300 keV, leading to a significantly improved 25 Mg( n,γ ) 26 Mg parametrization. The relevant resonances for n+25 Mg were characte...

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Detalles Bibliográficos
Autores principales: Massimi, C., Altstadt, S., Andrzejewski, J., Audouin, L., Barbagallo, M., Bécares, V., Bečvář, F., Belloni, F., Berthoumieux, E., Billowes, J., Bisterzo, S., Bosnar, D., Brugger, M., Calviani, M., Calviño, F., Cano-Ott, D., Carrapiço, C., Castelluccio, D.M., Cerutti, F., Chiaveri, E., Cosentino, L., Chin, M., Clai, G., Colonna, N., Cortés, G., Cortés-Giraldo, M.A., Cristallo, S., Diakaki, M., Domingo-Pardo, C., Duran, I., Dressler, R., Eleftheriadis, C., Ferrari, A., Finocchiaro, P., Fraval, K., Ganesan, S., García, A.R., Giubrone, G., Gonçalves, I.F., González-Romero, E., Griesmayer, E., Guerrero, C., Gunsing, F., Hernández-Prieto, A., Jenkins, D.G., Jericha, E., Kadi, Y., Käppeler, F., Karadimos, D., Kivel, N., Koehler, P., Kokkoris, M., Kopecky, S., Krtička, M., Kroll, J., Lampoudis, C., Langer, C., Leal-Cidoncha, E., Lederer, C., Leeb, H., Leong, L.S., Lo Meo, S., Losito, R., Mallick, A., Manousos, A., Marganiec, J., Martínez, T., Mastinu, P.F., Mastromarco, M., Mendoza, E., Mengoni, A., Milazzo, P.M., Mingrone, F., Mirea, M., Mondelaers, W., Musumarra, A., Paradela, C., Pavlik, A., Perkowski, J., Pignatari, M., Piersanti, L., Plompen, A., Praena, J., Quesada, J.M., Rauscher, T., Reifarth, R., Riego, A., Robles, M.S., Rubbia, C., Sabaté-Gilarte, M., Sarmento, R., Saxena, A., Schillebeeckx, P., Schmidt, S., Schumann, D., Tagliente, G., Tain, J.L., Tarrío, D., Tassan-Got, L., Tsinganis, A., Valenta, S., Vannini, G., Van Rijs, I., Variale, V., Vaz, P., Ventura, A., Vermeulen, M.J., Vlachoudis, V., Vlastou, R., Wallner, A., Ware, T., Weigand, M., Weiß, C., Wynants, R., Wright, T., Žugec, P.
Lenguaje:eng
Publicado: 2017
Materias:
nucl-ex
Nuclear Physics - Experiment
Acceso en línea:https://dx.doi.org/10.1016/j.physletb.2017.02.025
http://cds.cern.ch/record/2253417
Descripción
Sumario:This work reports on accurate, high-resolution measurements of the 25 Mg( n,γ ) 26 Mg and 25 Mg( n,tot ) cross sections in the neutron energy range from thermal to about 300 keV, leading to a significantly improved 25 Mg( n,γ ) 26 Mg parametrization. The relevant resonances for n+25 Mg were characterized from a combined R-matrix analysis of the experimental data. This resulted in an unambiguous spin/parity assignment of the corresponding excited states in 26 Mg. With this information experimental upper limits of the reaction rates for 22 Ne( α,n ) 25 Mg and 22 Ne( α,γ ) 26 Mg were established, potentially leading to a significantly higher (α,n)/(α,γ) ratio than previously evaluated. The impact of these results has been studied for stellar models in the mass range 2 to 25 M⊙ .

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