Abstract
The precise determination of the neutron capture cross sections of and is important to define the -process abundance of at the formation of the solar system. This quantity can be used to evaluate the radiogenic component of the abundance of due to the decay of the unstable ( Gyr) and from this to infer the time duration of the nucleosynthesis in our galaxy (Re/Os cosmochronometer). The neutron capture cross sections of , , and 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 D scintillation detectors for recording the prompt rays emitted in the capture events. Maxwellian averaged capture cross sections have been determined for thermal energies between and 100 keV corresponding to all possible -process scenarios. The estimated uncertainties for the values at 30 keV are 4.1, 3.3, and for , , and , respectively.
- Received 15 December 2009
DOI:https://doi.org/10.1103/PhysRevC.82.015802
©2010 American Physical Society
Synopsis
An ancient clock
Published 15 July 2010
Refining a cosmic clock gives a more accurate reading of the age of our galaxy.
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