FIELD: radiation measurement. SUBSTANCE: examined sample of air is placed into ionization chamber with two electrodes between which electric field is formed. Intensity of electric field near internal electrode is chosen sufficient for collision ionization by electrons. First negative potential is fed to internal electrode and electric pulses from alpha particles formed in space of chamber and on surfaces of electrodes are registered. Then polarity is changed and number of pulses from alpha particles passing through region of collision ionization close to internal electrode is measured. EFFECT: separate registration of radon and its by-products. 4 cl
