Skliarov, V.Degtiarov, O.Zaporozhets, O.2022-01-052022-01-052021Skliarov V. State of art of radon and thoron volume activity measurements / V. Skliarov, O. Degtiarov, O Zaporozhets // 31 st INTERNATIONAL SCIENTIFIC SYMPOSIUM METROLOGY AND METROLOGY ASSURANCE 2021 September 7-11, 2021, Sozopol, Bulgariahttps://openarchive.nure.ua/handle/document/18999control, monitoring and reduction of the dose load from ionizing radiation to the population is a national task, which is determined and coordinated by a number of Laws and Resolutions of the Cabinet of Ministers of Ukraine. Based on the accumulated experience in the creation and operation of the state primary standard for the unit of volumetric activity 222Rn, a methodology for creating the state primary standard for the unit of volumetric activity 222Rn (radon) and 220Rn (thoron) is proposed. The natural background radiation consists of cosmic radiation and radiation from natural radionuclides (232Th, 226Ra, 40K) common in the Earth's crust, soil, air, water and other objects of the external environment. Some part of the territory of Ukraine is located on the Ukrainian crystal shield with significant reserves of 226Ra and 232Th and, as a result, 222Rn (radon) and 220Rn (thoron) emanations from the soil surface into the environment, housing and industrial premises. The purpose of this work is to develop the structure and concept of constructing the state primary standard of the unit of volumetric activity 222Rn and 220Rn based on the accumulated experience in the creation and operation of the state primary standard of the unit of volumetric activity 222Rn.enstate primary standardradon chamberthoron chambervolumetric activityradon generatorthoron generator.Article