The 222Rn radioisotope with 3.8 days decay half-life is produced form 238U natural series and the 220Rn radioisotope with 55 sec decay half-life form 232Th natural series. The radon gas can enter to the body via respiring, drinking and eating. The alpha emitted by this gas and other radiation emitted by its daughters increase the absorbed dose in respiratory and digestion systems. Nearly 50% of annually radiation dose absorption of human is due to radon which is one of the main cancers cause at respiratory and digestion systems. In this work, radon concentration in the 22 air positions and 8 water samples of mine in Nishabour region at Iran has been measured with PRASSI system. The result shows 12 air samples and 5 water samples have radon concentration gather than the normal level.
