Determination of Thorium and Uranium at the Nanogram Per Gram Level in Semiconductor Potting Plastics by Neutron Activation Analysis

摘要

A method was developed to determine thorium and uranium in semiconductor potting plastics. The method is based on neutron activation and subsequent radiochemical separation to isolate and permit measurement of the induced sup 233 Pa and sup 239 Np. These plastics typically contain macro amounts of silicon, bromine and antimony and nanogram per gram amounts of thorium and uranium. The radiochemical method provides the necessary sensitivity and makes it possible to easily attain adequate decontamination of the tiny amounts of sup 233 Pa and sup 239 Np from the high levels of radioactive bromine and antimony. 8 refs. (ERA citation 10:051898)