STUDY OF THE INFLUENCE OF SOIL MOISTURE AND GRAIN SIZE ON RADON EMANATION FROM SOIL USING AN ADVANCED MULTIGRAIN MODEL.

Among the most important factors that influence radon emanation from soil particles is the soil moisture and grain size. Both components, in its own way, modify the length of a trajectory that radon atom pass through in a volume of the soil pores. To better understand their impact on an emanation, we have developed our own computer program that can simulate the 222Rn emanation process in the soil environment, using an idea of a multigrain model. In our case, the central, radium-bearing soil grain is surrounded by 1330 adjacent grains of the same size forming a cubic structure and the moisture in a space of the soil pores is differently distributed. The simulation process is based on a two different distribution of 226Ra in soil grains (homogenous and heterogenous), while several variants of the thickness of an escape layer are analyzed for grains of different sizes and moisture contents.