Preparation of 10Be and the Measurement of Isotopic Ratio of Beryllium

10Be was produced by neutron irradiation of boron nitride and beryllium metal. As for beryllium metal sample, 10Be was enriched by an isotope separator at the Institute for Nuclear Study. As for boron nitride sample, an isotopic abundance of 10Be was measured by the surface ionization method. The mass spectrum was obtained for 3.0×10-9g of 10Be in the presence of the same quantity of 9Be, mounted on a rhenium single filament with silica-gel. The amount of beryllium was determined by isotope dilution analysis. The discrimination factor of beryllium was estimated to be 1.05 per one mass unit