Thorium determination by neutron activation analysis

One method for Thorium analysis has been developed by Neutron Activation Analysis without using standards and by eliminating many of the error's source of absolute method. It uses the ratio of the activities induced by mass unit, between the Th in the sample and a Cobalt monitor. As a detection limit we have achieved 10ppm with relative standard deviation 5% for one flux sub(2x10)sup(11)n cm-2s-1. This method is very useful for nuclear research center with small reactors in mineral prospecting programs. (author)