Application of a “Sealed Can Technique” and CR-39 detectors for measuring radon emanation from undamaged granitic ornamental building materials

Environmental Radiometric Division, Instituto de Pesquisas Energéticas e Nucleares, Av. Prof. Lineu Prestes, 2242, Cidade Universitária, 05508-000 São Paulo, SP, Brazil

Abstract

Radon (²²²Rn) is the most important cause of exposure to mankind due to natural radioactivity. Radon exhalation depends not only on the ²²⁶Ra concentration in the material, but also on other factors such as mineralogy of the region, size and density of grains and porosity of the material. As building materials are one of the major sources of environmental radon, the radiological implications of the use of materials with great content of uranium must be always assessed. In this work, radon exhalation from several undamaged granitic building materials used as ornamental rocks or coating tiles is determined using the “sealed-can technique” and CR-39 solid state nuclear track detectors (SSNTD). Preliminary results for radon concentrations showed values of the same order that literature values, in a range from 99 Bq.m⁻³ to 1100 Bq m⁻³. Further, the methodology will be validated with standard sources of ²²²Rn.