corner
corner

Phys. Rev. C 82, 015804 (2010) [18 pages]

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

Download: PDF (640 kB) Buy this article Export: BibTeX or EndNote (RIS)

K. Fujii et al. (The n_TOF Collaboration)
Show All Authors/Affiliations

Received 14 December 2009; published 15 July 2010

See accompanying Physics Synopsis

Neutron resonance analyses have been performed for the capture cross sections of 186Os, 187Os, and 188Os measured at the n_TOF 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 187Os abundance and the related impact on the evaluation of the time duration of galactic nucleosynthesis via the Re/Os cosmochronometer are discussed.

© 2010 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevC.82.015804
DOI:
10.1103/PhysRevC.82.015804
PACS:
21.10.Ma, 25.40.Lw, 26.20.Kn, 27.70.+q

See Also

See Also: M. Mosconi et al. (The n_TOF Collaboration), Neutron physics of the Re/Os clock. I. Measurement of the (n,γ) cross sections of 186,187,188Os at the CERN n_TOF facility, Phys. Rev. C 82, 015802 (2010).

See Also: M. Mosconi, M. Heil, F. Käppeler, R. Plag, and A. Mengoni, Neutron physics of the Re/Os clock. II. The (n,n) cross section of 187Os at 30 keV neutron energy, Phys. Rev. C 82, 015803 (2010).