1991 Volume 7 Issue Supple Pages 1255-1258
Neutron activation analysis for thorium and uranium in high purity silica and aluminum was investigated. The activation products 233Pa and 239Np for the determination of thorium and uranium were separated from majority of interfering radioactivity by a method combined with anion exchange and LaF3 coprecipitation. It was found that the analysis with detection limit of several ppt for both uranium and thorium was possible when a high flux reactor was used. The method is useful for the determination of uranium and thorium in semiconductor grade silica and aluminum.