FIELD: radiation measurements, biology, ecology and environment protection. SUBSTANCE: method involves use of beta-spectrometer for measuring total count of sample with respect to region of main radiation power of beta-particles of strontium-90. Then method involves use of gamma-spectrometer for detection of specific activity of all radio nuclides which are present in this sample and are simultaneously gamma and beta emitters. Said specific activities are converted to count speed using reference sensitivity of beta- spectrometer to latter radio nuclides also in region of main radiation power of beta-particles of strontium-90. Specific activity of strontium-90 is calculated by subtraction of total count all counts of beta and gamma nuclides and conversion of this difference to specific activity with respect to sensitivity of beta-spectrometer to strontium-90. EFFECT: increased functional capabilities. 2 cl
