Re/Os Cosmochronometer: Measurement of Neutron Cross Sections

The Re/Os cosmochronometer is a dating technique based on the decay of 187Re into 187Os. It determines the age of the universe by the time of onset of nucleosynthesis. The nucleosynthesis mechanisms, which are responsible for the 187Re/187Os pair, provide the possibility to identify the radiogenic fraction of 187Os by nuclear physics considerations. The neutron capture cross sections averaged over the stellar conditions of the s-process are the input for the calculations of the 187Os abundance.