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

Journal Article · Thu Jul 15 00:00:00 EDT 2010 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.82.015804· OSTI ID:21389232

Fujii, K; Abbondanno, U; Belloni, F; Milazzo, P M; Moreau, C ^[1]; Mosconi, M; Kaeppeler, F; Audouin, L; Dillmann, I; Heil, M; Plag, R; Voss, F; Walter, S; Wisshak, K ^[2]; Mengoni, A ^[3]; CERN, CH-1211 Geneva ^[4]; Domingo-Pardo, C ^[2]; Aerts, G; Andriamonje, S; Berthoumieux, E ; Dridi, W ^[5]

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1. Istituto Nazionale di Fisica Nucleare, I-34149 Trieste (Italy)
2. Karlsruhe Institute of Technology (KIT), Campus Nord, Institut fuer Kernphysik, D-76021 Karlsruhe (Germany)
3. International Atomic Energy Agency, NAPC-Nuclear Data Section, A-1400 Vienna (Austria)
4. Switzerland
5. CEA/Saclay, DSM, F-91191 Gif-sur-Yvette (France)

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.

• OSTI ID: 21389232
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 82, Issue 1; Other Information: DOI: 10.1103/PhysRevC.82.015804; (c) 2010 The American Physical Society; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
CAPTURE
CERN
CROSS SECTIONS
EVALUATION
EXCITED STATES
ISOTOPE RATIO
KEV RANGE
NEUTRON REACTIONS
NEUTRONS
NUCLEOSYNTHESIS
OSMIUM 186
OSMIUM 187
OSMIUM 188
R MATRIX
RESONANCE
RHENIUM 187
S PROCESS
SIMULATION
STARS
STATISTICAL MODELS
TEMPERATURE RANGE
ALPHA DECAY RADIOISOTOPES
BARYON REACTIONS
BARYONS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
DIMENSIONLESS NUMBERS
ELEMENTARY PARTICLES
ENERGY LEVELS
ENERGY RANGE
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
EVOLUTION
FERMIONS
HADRON REACTIONS
HADRONS
HEAVY NUCLEI
INTERNATIONAL ORGANIZATIONS
ISOTOPES
MATHEMATICAL MODELS
MATRICES
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
NUCLEONS
ODD-EVEN NUCLEI
OSMIUM ISOTOPES
RADIOISOTOPES
RHENIUM ISOTOPES
STABLE ISOTOPES
STAR EVOLUTION
SYNTHESIS
YEARS LIVING RADIOISOTOPES