Direct determination of radionuclides in building materials with self-absorption correction for the 63 and 186 keV γ-energy lines

The use of 911 keV and 129 keV gamma-line intensity ratio has been applied for self-absorption correction of the 63 key Th-234 (U-238) and 186 keV(Ra-226 and U-235) lines in typical building materials and soil samples. Proposed procedure allows to determine 238U from the Th-234 line (63 key) and Ra-226 after subtraction of U-235 interference in the 186 keV. It is important in the case of low uranium concentration and weak intensity of U-235 143 keV gamma energy line, when activity of this radionuclide can be apprised on the natural constant U-238/U-235 ratio, only (excluding accidental anthropogenic depleted uranium deposition in the soil samples). Therefore, by this method a direct and fast determination of the Ra-226 and other important radionuclides, without one month waiting period for Ra-226-Rn-222 daughter equilibrium, is possible. The accuracy of the method has been confirmed (relative relation deviation <10%) for typical buildings materials such as: tales, bricks, concrete blocks and various type of ceramic materials. (C) 2015 Elsevier Ltd. All rights reserved.