Abstract

• Radon is an alpha emitting radioactive gas. It can exist in ground water, soil, building materials mines, caves and other underground places. In this study, radon concentration in old buildings and new buildings was measured by using LR-115 type II detector in a can mode. The preliminary study, the LR-115 detector was treated with alpha emitter Am-241 for standard. The tracks formed in LR-115 were etched with 2.5 M NaOH at 60 °C for 90 min. The etched tracks in irradiated LR115 detector were found to be spherical shape by using optical microscope. And then, radon level in old buildings and new buildings was measured by LR-115 detector using the same procedure. The observed shape of track agrees with the preliminary study and it indicates that this is due to interaction between detector and alpha particles via radon present in old and new buildings. The average track density was found to be 133.5484 and 312.3674 track/cm2d in all detectors in Bagaya Monastery and Me Nu Oak Kyaung. According to the observed track density, the average radon activity was found to be 667.7418 and 1561.8369 Bq/m3 in all detectors in Bagaya Monastery and Me Nu Oak Kyaung. The calculated radon exhalation rate mean values were 1.0755 and 2.5155 mBq/m2h in Bagaya Monastery and Me Nu Oak Kyaung. The average radon concentration was found to be 10.7548 and 25.1553 Bq/m3 in Bagaya Monsatery and Me Nu Oak Kyaung. The average track density was found to be 39.0459 and 84.8824 track/cm2d in all detectors in new buildings at Sagaing and Monywa. According to the observed track density, the average radon activity was found to be 185.9329 and 404.2021 Bq/m3 in all detectors in new buildings at Sagaing and Monywa. The calculated radon exhalation rate mean values were 0.3095 and 0.6728 mBq/m2h in new buildings at Sagaing and Monywa. The average radon concentration was found to be 3.0949 and 6.7279 Bq/m3 in new buildings at Sagaing and Monywa.