Measurement of annual effective dose for Radon in Kerbala University Campus, Freiha, Iraq

Abstract

This study measures the annual effective dose and concentrations of radon in indoor building in Kerbala University, Freiha-Iraq. Radon concentrations were determined using time-integrated passive radon dosimeters open and closed containing (CR-39) solid-state nuclear track detectors. Measurements were carried out during the months of March and April of 2015.Twenty-two open and closed dosimeters were distributed in the building of the study area. After exposure, the detectors were etched in a (NaOH) solution of normality (6.25 N) at a temperature of 70oC for 8 hours. The tracks were counted by the microscope track-counting system.In closed dosimeters, the results show that the radon concentrations varied from (17.969 ± Bq/m3) to (88.975 ± Bq/m3) with an average value (51.554 ± 28.284 Bq/m3). In open dosimeters, the results show that the radon concentrations varied from (27.231 ± Bq/m3) to (95.150 ± Bq/m3) with an average value (60.348 ± 27.202 Bq/m3) which is less than the lower limit of the recommended range (200–300 Bq/m3) (ICRP, 2009). The values of the indoor annual effective dose vary from (0.036 mSv/y) to (0.636 mSv/y) with an average value (0.161 mSv/y) for open dosimeters and vary from 0.033 mSv/y to 0.389 mSv/y with an average value 0.113 mSv/y for closed dosimeters which is less than the lower limit of the recommended range (3–10 mSv/y) (ICRP, 1993).The values of equilibrium factor vary from (0.009) to (0.203) with an average value (0.053) which is less than the lower limit of the recommended range (0.4–1) (ICRP, 1993).