AbstractThe thermal neutron-capture cross section of 1.0-year Ru106has been determined from the yield of 22-min Rh107formed in reactor irradiations. The average of four measurements is 0.146 barns. The experimental error is about±7% but when systematic errors are included, largely in gamma-ray abundances from Ru106and Rh107decay, the uncertainty is about 30%. Cadmium-ratio measurements were made and the resonance-capture integral, including the 1/υpart, was found to be 2.0±0.6 barns for an effective cadmium cutoff of 0.54 eV. These results are relative to a cobalt thermal neutron-capture cross section of 37.5 barns and total resonance integral of 72.7 barns. It has been assumed that neutron capture by Rh106, Ru107and Rh107is negligible, that the cross section of Ru106in the thermal region has a 1/υdependence and that the neutron spectrum is 1/Ein the resonance region.