抄録
Radon was discovered in the beginning of the twentieth century. Its recoil ranges and diffusion coefficients are so small in common minerals that the radon amount emanated from them has been thought to be very small. However the measured radon amount actually emanated was noticeably larger than the predicted value. Therefore, over the years, many research studies have been done to explain this mismatch. Also many measurements of radon emanation coefficients of various materials and radon concentrations in the atmosphere have been made by researchers worldwide. These activities have been done primarily because of the potential health effects brought about by radiation exposure from radon. On the other hand, the extent of radon recoil ranges in porous materials and radon diffusion lengths near solid surfaces is commensurate with various representative parameters such as pore sizes and solid surface geometry. This means that radon emanation phenomena would be applicable to study the physical properties of porous materials and solid surfaces now and in the future. This paper overviews the above mentioned fields of study.
