Neutron capture on Zr-94: Resonance parameters and Maxwellian-averaged cross sections

The neutron capture cross sections of the Zr isotopes play an important role in nucleosynthesis studies. The s-process reaction flow between the Fe seed and the heavier isotopes passes through the neutron magic nucleus Zr-90 and through Zr-91,Zr-92,Zr-93,Zr-94, but only part of the flow extends to Zr-96 because of the branching point at Zr-95. Apart from their effect on the s-process flow, the comparably small isotopic (n, gamma) cross sections make Zr also an interesting structural material for nuclear reactors. The Zr-94 (n, gamma) cross section has been measured with high resolution at the spallation neutron source n_TOF at CERN and resonance parameters are reported up to 60 keV neutron energy.