for the n_TOF collaboration
The radiative neutron capture cross sections of 186Os and
187Os have fundamental importance for the analysis of the Re/Os
cosmochronometer. These data allow one to discriminate the amount of 187Os
producted by nucleosynthesis from the one generated by radioactive decay
of 187Re, an information related to onset of nucleosynthesis
of the heavy elements.
The capture cross sections of the three stable isotopes 186Os,187Os, and 188Os have been measured at the CERN n_TOF facility in the energy range from 1 eV to ~ 1 MeV. This contribution reports on preliminary cross section results.