Application of carbone gamma-ray data used for the uranium exploration to the study of natural radiation

Abstract

Numerous data of gamma-ray total count rates have been accumulated during the past two decades by carborne gamma-ray survey which was carried out for the uranium exploration in Japan by Power Reactor and Nuclear Fuel Development Corporation. We describe a me convert existing carbone data into absorbed dose rate and briefly review the current research to know the background level of the natural radiation. New carborne system with twelve NaI(T1) cylindrical crystals was introduced to convert previous data into absorbed dose rate because the previous carborne system does not exist at present. The new carborne test survey results in a good linear relationship between count rates and absorbed dose rates, which enables us to successfully convert the total count rates into absorbed dose rate. It is suggested that the earlier carborne data accumulated during domestic uranium exploration can be effectively used to delineate detail maps of with respect to distribution of natural radiation in Japan. (author).