[Measurement of 222Rn in air using liquid scintillation techniques (author's transl)]

A simple method for the measurement of 222Rn in air was established. At first step radon daughters in air were eliminated from air by suction using glass fiber filter, after that the air were introduced directly to the scrubbing bottle filled with scintillator based on toluene and bubbled until the concentration of 222Rn in the liquid scintillator reached equilibrium state. Then 120ml of the bubbled liquid scintillator were sealed in the teflon vial for the measurement of radioactivity. After the radioactive equilibrium between 222Rn and its daughters were reached, the radioactivity were measured by the low background liquid scintillation counter. The detection limit of 222Rn in air by this method was 3 x 10(-3) Bq/l air (8 x 10(-14)Ci/l air). Though alpha spectrometry by multi-channel analyzer was also achieved, the integral counting method was used more effectively. This method was effectively applied to determine the relatively high concentration of 222Rn in air.