An approximation to estimate the total radium from measurements of the effective radium

According to several studies, the distribution of parent radium atoms (²²⁶Ra) in soil grains, and grain size distribution are important factors affecting radon emanation. Thus, we have conducted experiments and simulation studies to estimate the radon emanation factor and the effective radium content as a function of grain size. Experimentally, the effective radium was determined by using the nuclear track methodology and the total radium by gamma-ray spectrometry. A calculation algorithm, based on Monte Carlo simulations, was applied to the simple single-grain spherical model to study the radon emanation process. The SRIM software was used to calculate the minimum grain radius at which radon escape completely from the grain. Results indicate that as the grain size decreases it is possible to obtain an approximate value of the total radium by means of the corresponding effective radium measurements. (author)