Radon exhalation rate from different types of building construction materials through SSNTD's

Building materials are the main source of radon inside the dwellings. Because of low level of radon emanation from these materials, long term measurements are essential. Can technique using solid state nuclear track detector can be employed conveniently and successfully for these measurements. Radon activity and exhalation rate are measured in a number of building materials commonly used for building construction in our region by Can technique using LR-115 type II nuclear track detector. Radon activity is found to vary from 288.8 to 6885.7 Bqm-3 with an average value 1992.6 Bqm-3 and radon exhalation rate varies from 174.6 to 4162.8 mBqm-2h-l for different building materials. Radon emanation from unfired bricks is found to be maximum while marble and ceramic tiles give minimum radon emanation. In unfired bricks it appears that radon emanation is produced not only from the surface layers but also from inside the brick. Effective dose equivalent for radon decay products is estimated to vary from 20.5 to 490.8 μSv y-1. (author)