METHOD OF DETERMINING SPECIFIC ACTIVITY OF THORIUM-228 IN SOIL Russian patent published in 2008 - IPC G01T1/167 

FIELD: analytical methods in environmental monitoring.

SUBSTANCE: invention relates to radiation monitoring of soils of economies where mineral fertilizers were added to land over a long period of time and caused considerable accumulation of ²²⁸Th and other radionuclides in soil. Sample of soil is held in a sealed vessel over 20-day period. Lead chromate, 5-10 h after isolation thereof from soil, is analyzed by γ-spectrometry technique according to γ line of ²⁰⁸Tl 2.615 MeV. On the same device, equilibrium calibrated source of ²²⁶Ra is analyzed according to line ²¹⁴Bi 2.448 MeV. From found γ lines taking into consideration duration of their accumulation, specific activity of ²²⁸Th in soil sample is determined.

EFFECT: simplified analysis.