Half-Life of Yttrium-90

A series of determinations on the half-life of yttrium-90 have been made, resulting in an average value of 64.24±0.30 hours. ${\mathrm{Y}}^{90}$ was separated from its ${\mathrm{Sr}}^{90}$ mother by either a carbonate or phosphate precipitation, followed by conversion to oxalate as the final counting vehicle. The efficiency of the chemical separations, precision of the determinations, and good agreement with the latest published results suggest that the half-life of this nuclide is now known to an accuracy of 0.7 percent.