Jyoti Sharma, A. K. Mahur3,, Rupesh Kumar, Rati Varshney, R. G. Sonkawade, R. Swarup, Hargyan Singh and Rajendra Prasad
As the radon progeny contribute a major part of natural radiation dose to general population, attention has been given to the large scale and long term measurement of radon and its progeny. Recent epidemiological evidence suggests that inhalation of low level radon and its progeny in dwellings may contribute towards the cause of lung cancer. Thoron and its progeny contribute little for the radiation dose in normal back ground region due to its small half life. In this comparative study Solid State Nuclear Track Detectors (SSNTD’s) based twin chamber dosimeters were used for estimating radon (222Rn), Thoron (220Rn) gases and Inhalation dose in some historical places at Jaipur, Rajasthan, India using twin chamber dosimeter cups. The dosimeters employ two LR-115 type II plastic track detector peliculable films, cellulose nitrate detector films inside each of the two chambers fitted with filter and polymeric membrane for the discrimination of radon and thoron. Soil samples were also collected simultaneously from different geological formations of the same area for laboratory measurement of radon exhalations rate. Radon concentrations are found to vary from (18.4 ± 3.1) Bq m-3 to (62.1 ± 5.7) Bq m-3, whereas thoron concentrations vary from (5.9 ± 0.6) Bq m-3 to (22.0 ± 2.6) Bq m-3. Radon activity and radon exhalation rates in the soil samples were also measured by using “Sealed can technique” using LR 115-type II nuclear track detectors. Radon activities are found to vary from (294.2) to (868.4) Bqm-3 with an average value of (566.0) Bqm-3. Radon exhalation rates in these samples vary from (146.8) to (312.2) mBq m-2 h-1with an average value of (203.4) mBq m-2 h-1.
