Neutron physics of the Re/Os clock. III. Resonance analyses and stellar (n,gamma) cross sections of {sup 186,187,188}Os

• Published in: Physical review. C, Nuclear physics Nuclear physics, 2010-07, Vol.82 (1)
• Main Authors: Fujii, K., Abbondanno, U., Belloni, F., Milazzo, P. M., Moreau, C., Mosconi, M., Kaeppeler, F., Audouin, L., Dillmann, I., Heil, M., Plag, R., Voss, F., Walter, S., Wisshak, K., Mengoni, A., CERN, CH-1211 Geneva, Domingo-Pardo, C., Instituto de Fisica Corpuscular, CSIC-Universidad de Valencia, E-46980 Paterna, Aerts, G., Andriamonje, S., Berthoumieux, E., Dridi, W.
• Format: Article
• Language: English
• Subjects: ALPHA DECAY RADIOISOTOPES; BARYON REACTIONS; BARYONS; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; CAPTURE; CERN; CROSS SECTIONS; DIMENSIONLESS NUMBERS; ELEMENTARY PARTICLES; ENERGY LEVELS; ENERGY RANGE; EVALUATION; EVEN-EVEN NUCLEI; EVEN-ODD NUCLEI; EVOLUTION; EXCITED STATES; FERMIONS; HADRON REACTIONS; HADRONS; HEAVY NUCLEI; INTERNATIONAL ORGANIZATIONS; ISOTOPE RATIO; ISOTOPES; KEV RANGE; MATHEMATICAL MODELS; MATRICES; NEUTRON REACTIONS; NEUTRONS; NUCLEAR PHYSICS AND RADIATION PHYSICS; NUCLEAR REACTIONS; NUCLEI; NUCLEON REACTIONS; NUCLEONS; NUCLEOSYNTHESIS; ODD-EVEN NUCLEI; OSMIUM 186; OSMIUM 187; OSMIUM 188; OSMIUM ISOTOPES; R MATRIX; RADIOISOTOPES; RESONANCE; RHENIUM 187; RHENIUM ISOTOPES; S PROCESS; SIMULATION; STABLE ISOTOPES; STAR EVOLUTION; STARS; STATISTICAL MODELS; SYNTHESIS; TEMPERATURE RANGE; YEARS LIVING RADIOISOTOPES
• ISSN: 0556-2813; 1089-490X
• DOI: 10.1103/PHYSREVC.82.015804

Neutron resonance analyses have been performed for the capture cross sections of {sup 186}Os, {sup 187}Os, and {sup 188}Os measured at the n{sub T}OF facility at cern. Resonance parameters have been extracted up to 5, 3, and 8 keV, respectively, using the sammy code for a full R-matrix fit of the capture yields. From these results average resonance parameters were derived by a statistical analysis to provide a comprehensive experimental basis for modeling of the stellar neutron capture rates of these isotopes in terms of the Hauser-Feshbach statistical model. Consistent calculations for the capture and inelastic reaction channels are crucial for the evaluation of stellar enhancement factors to correct the Maxwellian averaged cross sections obtained from experimental data for the effect of thermally populated excited states. These factors have been calculated for the full temperature range of current scenarios of s-process nucleosynthesis using the combined information of the experimental data in the region of resolved resonances and in the continuum. The consequences of this analysis for the s-process component of the {sup 187}Os abundance and the related impact on the evaluation of the time duration of galactic nucleosynthesis via the Re/Os cosmochronometer are discussed.