Capture Cross Section Measurements of ^186,187,188Os at n_TOF: The Resolved Resonance Region

Conference · Tue Jan 01 04:00:00 EST 2008

OSTI ID:971568

Fujii, K. ^[1]; Koehler, Paul Edward ^[2]

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1. Instituto Nazionale de Fisica Nucleare, Trieste, Italy
2. ORNL

The neutron capture cross sections of {sup 186,187,188}Os have been measured at the CERN neutron time-of-flight facility, n{_}TOF, in the neutron energy range from 1 eV up to 1 MeV. In this contribution, we report the results of the analysis of the resolved resonance region (RRR). Resonance parameters have been extracted from a full R-matrix fit of the capture yields with the SAMMY code. A statistical analysis has been performed and the related average resonance parameters are derived. This information is crucial for a complete understanding and modeling in terms of the Hauser-Feshbach statistical model of the capture and inelastic reaction channels, required for the evaluation of the stellar reaction rates of these isotopes. Maxwellian average cross sections for the range of temperatures relevant for s-process nucleosynthesis have been derived from the combined information of the experimental data in the resolved and unresolved resonance regions. A brief account of the implications of this analysis in the estimation of the s-process component of the {sup 187}Os abundance and the related impact on the estimates of the time-duration of the galactic nucleosynthesis through the Re/Os clock is given.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 971568
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ABUNDANCE
CAPTURE
CERN
CROSS SECTIONS
ENERGY RANGE
EVALUATION
NEUTRON REACTIONS
NEUTRONS
NUCLEOSYNTHESIS
R MATRIX
REACTION KINETICS
RESONANCE
S PROCESS
SIMULATION
STATISTICAL MODELS