FIELD: air analysis for radon. SUBSTANCE: examined sample of air is placed into chamber with two electrodes. Area of internal electrode is smaller by factor of 108 than area of external electrode. Electric field which intensity is sufficient for impact ionization by electrons near internal electrode is formed between external and internal electrodes. Minimum distance from boundary of region of impact ionization to surface of external electrode is selected to be bigger than maximum path of alpha particles of daughter products of decay of radon is. Then number of electric pulses from alpha particles is recorded and concentration of radon and daughter products of its decay is found. Polarity of electrodes is periodically changed to opposite one in process of measurements. EFFECT: possibility of separate registration of radon and daughter products of its decay. 1 cl
