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

Journal Article · Thu Jul 15 04:00:00 EDT 2010 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PhysRevC.82.015802· OSTI ID:1023345

Mosconi, M. ^[1]

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1. Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). et al.

The precise determination of the neutron capture cross sections of ¹⁸⁶Os and ¹⁸⁷Os is important to define the s-process abundance of ¹⁸⁷Os at the formation of the solar system. This quantity can be used to evaluate the radiogenic component of the abundance of ¹⁸⁷Os due to the decay of the unstable ¹⁸⁷Re (t_1/2 = 41.2 Gyr) and from this to infer the time duration of the nucleosynthesis in our galaxy (Re/Os cosmochronometer). The neutron capture cross sections of ¹⁸⁶Os, ¹⁸⁷Os, and ¹⁸⁸Os have been measured at the CERN n_TOF facility from 1 eV to 1 MeV, covering the entire energy range of astrophysical interest. The measurement has been performed by time-of-flight technique using isotopically enriched samples and two C₆D₆ scintillation detectors for recording the prompt rays emitted in the capture events. Maxwellian averaged capture cross sections have been determined for thermal energies between kT = 5 and 100 keV corresponding to all possible s-process scenarios. Furthermore, the estimated uncertainties for the values at 30 keV are 4.1, 3.3, and 4.7% for ¹⁸⁶Os, ¹⁸⁷Os, and ¹⁸⁸Os, respectively.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Contributing Organization: The n_TOF Collaboration
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1023345
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 1 Vol. 82; ISSN 0556-2813
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS