STUDY OF RADIATION EXPOSURE DUE TO RADON, THORON AND THEIR PROGENY IN THE INDOOR ENVIRONMENT OF RAJPUR REGION OF UTTARAKHAND HIMALAYA.

In the present study, the measurements of indoor radon, thoron and their progeny concentrations have been carried out in the Rajpur region of Uttarakhand, Himalaya, India by using LR-115 solid-state nuclear track detector-based time-integrated techniques. The gas concentrations have been measured by single-entry pin-hole dosemeter technique, while for the progeny concentrations, deposition-based Direct Thoron and Radon Progeny Sensor technique has been used. The radiation doses due to the inhalation of radon, thoron and progeny have also been determined by using obtained concentrations of radon, thoron and their progeny in the study area. The average radon concentration varies from 75 to 123 Bq m with an overall average of 89 Bq m The average thoron concentration varies from 29 to 55 Bq m with an overall average of 38 Bq m The total annual effective dose received due to radon, thoron and their progeny varies from 2.4 to 4.1 mSv y with an average of 2.9 mSv y While the average equilibrium factor for radon and its progeny was found to be 0.39, for thoron and its progeny, it was 0.06.