Classification of ores used for the radiation source in NORM as consumer products by PGAA

NORM means Naturally Occurring RadioactiveMaterial. Our object in this study is only consumer productsin several kinds of NORM. The existence of NORM in ourliving-environment raises the radiation exposure dose of theusers. This has become a world-wide issue. The sourcesof NORMs are mainly radionuclides in the thorium (Th)and uranium (U) series. However, we have little publishedinformation about the kinds of ores added to NORMs andthere are little indications on the NORMs\u27labels. It is wellknownthat Th and U usually exist with rare earth elements.So we sought a classification method for identifying the kindsof ores added to the consumer products from the correlationof the concentration ratios of the Th/U and the Gd/Sm inNORM and ores. The conventional r-ray spectrometry bya Ge detector for analysis of Th and U and the promptgamma-ray activation analysis for the determination of Smand Gd were employed. It was found that the radiationsources of NORM in the consumer products in recent marketswere mainly monazite. This classification method is found tobe useful to identify the ores used for the radiation sources inconsumer products of NORMs