Separation and α-Spectrometric Determination of the Isotopic Compositions of Uranium, Protactinium and Thorium and Their Applications on Dating Uranium Glass

A flow sheet for the isolation of uranium, thorium and protactinium with high radiochemical purity from uranium matrices was developed. The isotopic compositions and the chemical yield of the different metal ions separated were determined by α-spectroscopy and isotopic dilution, respectively. The developed flow sheet was applied to analyse two uranium matrices, namely: a pitchblende mineral from Atabaska, Canada and old uranium glass manufactured in Joachimsthal, Czechoslovakia. From the isotopic compositions determined, it is found that the uranium in the pitchblende mineral is in equilibrium with its daughters. On the other hand, the activity ratios; 234U/238U, 238U/235U, 231Pa/235U and 230Th/234U determined for the uranium glass indicated that this glass was manufactured since 164 ± 16 years and the uranium used in coloring this glass was not completely purified from the 230Th daughter of 234U.