Measurement of trace impurities in high purity materials

Neutron activation analysis was used for the determination of 29 trace impurities is high-purity semiconductor grade Ge and Si. In order to determine very low contents of uranium and thorium,²³⁹Np and²³³Pa activation products were separated using anion exchange and LaF₃ coprecipitation methods. The impurity contents were found to be very low, and therefore their adverse effects would be negligible.