DEPENDENCE OF THE RADON EMANATION COEFFICIENT ON RADIUM DISTRIBUTION AND INTERNAL STRUCTURE OF THE MATERIAL

The mechanisms of escape of radon from the solid structure of a partic le to the free pore space are examined. According to the present state of knowledge, the most important factors affecting the radon emanatio n coefficient are the distribution of the parent radium atoms and the internal structure of the material. In early studies of the radon eman ation coefficient, it was usually assumed that the material under inve stigation was homogeneous in radium distribution and in internal struc ture. It is now known that these assumptions are often not justified f or real materials. In consequence, models based on these assumptions m ay not be useful in explaining the emanation process. The importance o f radium distribution and internal structure is explained here, and an analysis made of differences in the internal structure of various nat ural and man-made materials. The analysis is then developed in order t o identify the effect of different models of radium atom distribution on the emanation coefficient. Four models of radium atom distribution are presented, together with mathematical approaches for developing an d finding numerical solutions for equations leading to determination o f the emanation coefficient for each model.