Determination of thorium and uranium at the nanogram per gram level in semiconductor potting plastics by neutron activation analysis

Abstract

A method was developed to determine thorium and uranium in semiconductor potting plastics. The method is based on neutron activation and subsequent radiochercical separation to isolate and permit measurement of the induced 2 33p a an( j 239^p > 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 233p a and 239 Np from the high levels of radioactive bromine and antimony.