Radon Concentrations and Annual Effective Dose in Some Dwellings of Aun Region in Kerbala Governorate, Iraq

radon concentrations and annual effective dose were measured in some dwellings of Aunregion in Kerbala governorate, Iraq. Radon concentrations were determined using timeintegratedpassive radon dosimeters open and closed containing (CR-39) solid state nuclear trackdetectors. Measurements were carried out during the months (January and February of 2015).Twenty open and twenty closed dosimeters were distributed in twenty dwelling of the study area.After two months of exposure the detectors were etched in a (NaOH) solution of normality (6.25N) at a temperature of 70o C for eight hours. The tracks were counted using an opticalmicroscope having a magnification of 400X.In closed dosimeters, the results show that, the radon concentrations varied from (20.508±0.603Bq/m3) to (137.149±4.033 Bq/m3) with an average value (63.767±1.875 Bq/m3), while thevalues of the indoor annual effective dose vary from (0.016±0.004 mSv/y) to (0.266±0.078mSv/y) with an average value (0.115±0.033 mSv/y). In open dosimeters, the results show that,the radon concentrations varied from (21.790 ±0.640 Bq/m3) to (152.530±4.486 Bq/m3) with anaverage value (75.047±2.207 Bq/m3), while the values of the indoor annual effective dose varyfrom (0.017±0.005 mSv/y) to (0.357±0.105 mSv/y) with an average value (0.145 ±0.042 mSv/y).These values, which are less than the lower limit of the recommended range (200-300 Bq/m3)(ICRP, 2009) and (3-10 mSv/y) (ICRP, 1993) for indoor radon concentrations and indoorannual effective dose, respectively. The values of equilibrium factor vary from (0.010±0.002) to(0.567±0.166) with an average value (0.088±0.025) which is less than the lower limit of therecommended range (0.4-1) (ICRP, 1993). The radon concentrations and annual effective dosewere found to be lower than the higher level recommended by ICRP(200-300)Bq/m3 and (3-10)mSv/y, respectively. These levels were found to be consistent with those measured by otherworkers in other countries and these values are within safe limits.