Determination of radon exhalation rates from tiles using active and passive techniques

Measurements of radon exhalation rates for selected samples of tiles used in Saudi Arabia were carried out using active and passive measuring techniques. These samples were granite, marble and ceramic. In the active method, a PC-based radon gas analyzer with emanation container was used, while, in the passive method, PM-355 nuclear track detectors with the "can technique" were applied for 180 days. A comparison of the exhalation rates measured by the two techniques showed a good linear correlation coefficient of 0.7. The granite samples showed an average radon exhalation rate of 0.7 Bq m(-2) h(-1), which was higher than that of marble and ceramic by more than twofold. The radon exhalation rates measured by the "can technique" showed a non-uniform exhalation from the surface of the same tile. (C) 2001 Elsevier Science Ltd. All rights reserved.