Capote, RobertoLozano Leyva, Manuel LuisQuesada, J.Domingo Pardo, CésarAbbondanno, U.Aerts, G.Álvarez-Pol, H.Alvarez Velarde, F.2017-07-112017-07-112006-08-29Capote, R., Lozano Leyva, M.L., Quesada, J., Domingo Pardo, C., Abbondanno, U., Aerts, G.,...,Alvarez Velarde, F. (2006). New measurement of neutron capture resonances in 209 Bi. Physical Review C - Nuclear Physics, 74 (2), 025807-1-025807-10.0556-2813 (impreso)1089-490X (electrónico)http://hdl.handle.net/11441/62368The neutron capture cross section of 209 Bi has been measured at the CERN n TOF facility by employing the pulse-height-weighting technique. Improvements over previous measurements are mainly because of an optimized detection system, which led to a practically negligible neutron sensitivity. Additional experimental sources of systematic error, such as the electronic threshold in the detectors, summing of γ-rays, internal electron conversion, and the isomeric state in bismuth, have been taken into account. γ-Ray absorption effects inside the sample have been corrected by employing a nonpolynomial weighting function. Because 209 Bi is the last stable isotope in the reaction path of the stellar s -process, the Maxwellian averaged capture cross section is important for the recycling of the reaction flow by α decays. In the relevant stellar range of thermal energies between kT=5 and 8 keV our new capture rate is about 16% higher than the presently accepted value used for nucleosynthesis calculations. At this low temperature an important part of the heavy Pb-Bi isotopes are supposed to be synthesized by the s-process in the He shells of low mass, thermally pulsing asymptotic giant branch stars. With the improved set of cross sections we obtain an s-process fraction of 19±3% of the solar bismuth abundance, resulting in an r -process residual of 81±3%. The present (n, γ) cross-section measurement is also of relevance for the design of accelerator driven systems based on a liquid metal Pb/Bi spallation target.application/pdfengAttribution-NonCommercial-NoDerivatives 4.0 Internacionalhttp://creativecommons.org/licenses/by-nc-nd/4.0/info:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccesshttps://doi.org/10.1103/PhysRevC.74.025807