SYNTHETIC MIXTURES OF THORIUM ISOTOPES

A series of synthetic mixtures of thorium isotopes was prepared on a g ravimetrical basis. The starting compounds consisted of natural thoriu m Th-232 (99.99%) and highly enriched Th-230 (99.8%). These materials were chemically purified and characterized for isotopic composition an d chemical purity. Thorium dioxide (ThO2) was demonstrated to be a sui table compound for gravimetrical blending. The isotope amount ratios i n the mixtures ranged from 10(-2) to 3 x 10(-6). These synthetic isoto pe mixtures are to our knowledge, the first ever prepared for thorium and may serve for calibration purposes. Published by Elsevier Science B.V.