Thorium measurement by the six-crystal spectrometer PRIPYAT-2M

The coincidence method of thorium measurement developed on the six-crystal spectrometer PRIPYAT-2M, and based on coincidence counting of 583 keV photons from two-step cascade transitions which follow β−-decay of 208Tl, is presented. Besides the need for sample of a standardized geometry is avoided, in compare to some standard method of thorium measurement currently in use, the method has relatively high efficiency and a good sensitivity.