Instrumentational determination of uranium and thorium in natural objects

The results of using simultaneously two methods of intrumentational determination of U-238, Th-232, and their decay products in soil and bottom deposits are described. The errors of gamma-activational analysis of uranium and thorium are much lower than the errors of the gamma-spectrometric method. The results of independent instrumentational methods agree within the error limits due to the counting statistics with P = 0.95. It is best to combine these methods for radioecological examinations of regions with natural and technogenic anomalies of uranium and thorium and their decay products and for assessing the degree of departure from radiactive equilibrium in the uranium or thorium decay chains. These methods can supplement the neutron-activational and x-ray fluorescence methods used for composition cerification of standard samples of soil, rocks, and other natural objects.