FIELD: physics. SUBSTANCE: process of determination of activity of strontium-90 in natural objects involves measurement of counting rate of beta radiation from examined and standard preparations Sr90+Y90,, Ce144+Pr144 and Rh106+ Ru106 at two discrimination levels 0.5 and 0.9 MeV, determination of activity of yttrium-90 in preparation and recalculation to activity of strontium-90 in preparation. Precipitate of iron hydroxide containing yttrium-90 in mixture with other radionuclides formed after processing of solved sample in ammonia is used as examined preparation. EFFECT: speed-up of analysis of activity of strontium-90 in samples.
