Título:
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The 139La(n, gamma) cross section: key for the onset of the s-process
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Autor/a:
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Calviño Tavares, Francisco; Cortés Rossell, Guillem Pere; Poch Parés, Agustí; Pretel Sánchez, Carme
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Otros autores:
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Universitat Politècnica de Catalunya. Departament de Física i Enginyeria Nuclear; Universitat Politècnica de Catalunya. GREENER - Grup de recerca d'estudis energètics i de les radiacions |
Abstract:
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The nuclear resonance parameters and the capture cross section of the neutron magic isotope 139La have
been measured relative to 197Au in the energy range of 0.6 eV to 9 keV at the neutron time-of-flight (n TOF)
facility at CERN. We describe the experimental apparatus and the data analysis procedures, which concerned
mainly the efficiency correction by means of the pulse height weighting function technique and the determination
of different background components. We extracted the resonance parameters and the main nuclear quantities
such as the resonance integral RI = 10.8 ± 1.0 b, the average γ widths for s and p waves γ l=0 = 50.7 ±
5.4 meV and γ l=1 = 33.6 ± 6.9 meV, the nuclear level densities D l=0 = 252 ± 22 eV and D l=1 <
250 eV, and the neutron strength functions S0 = (0.82 ± 0.05) × 10−4 and S1 = (0.55 ± 0.04) × 10−4. These
results represent a significant improvement over previous data. The deduced Maxwellian-averaged capture cross
sections are important for the interpretation of the most recent spectroscopic observations in low-metallicity stars. |
Materia(s):
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-Àrees temàtiques de la UPC::Física -Radiative capture -Stars--Structure. -Radiació -Estels -- Estructura |
Derechos:
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Attribution-NonCommercial-NoDerivs 3.0 Spain
http://creativecommons.org/licenses/by-nc-nd/3.0/es/ |
Tipo de documento:
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Artículo - Versión publicada Artículo |
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