<p num="43">FIELD: measuring equipment.</p> <p num="44">SUBSTANCE: invention relates to a method of determining <sup>230</sup>Th alpha activity. Control of chemical yield of target nuclide is carried out by value of <sup>234</sup>Th isotope activity, contained in the studied mineral and in a state of secular equilibrium with parent isotope <sup>238</sup>U. Method comprises successive determination of the full value of uranium-238 alpha activity in a sample, then determination of coefficient of beta-setting, then determination of chemical yield of thorium-230 and full <sup>230</sup>Th alpha-activity in the sample. It is sufficient to use only one radio path required for controlling the chemical output of uranium-238.</p> <p num="45">EFFECT: determining chemical yield of thorium fraction and radioactivity of isotope <sup>230</sup>Th, with compliance of results with actual experimental data obtained during radiochemical analysis of polycase – Ti-Ta-niobate with mineral formula AB<sub>2</sub>O<sub>6</sub>.</p
