Radon emanation study of uranium ore samples from N. E. Nigeria

The radon emanation fraction of rhyolite and granite uranium ore samples from N. E. Nigeria, essentially phospho-uranylite and meta-autunite, and the variation of recorded γ-ray activity with particle size are presented. The results indicate emanation fractions of 0.22 for the phospho-uranylite ore and 0.31 for the meta-autunite ore. The emanation of the two ores varies with grain size. Activity relative to 226Ra is highest for −250 + 180 μm grain size for rhyolite while there is a general increase in the relative activity of radon as grain size increases for granite.