Changes in the surface radioactivity of lead—the effect of the diffusion of bismuth and polonium radioisotopes

Abstract

Measurements and the quantitative analysis of the kinetics of the phenomenon of increasing radioactivity of lead after the scraping of the surface are presented. The growth of radioactivity concerns the α activity of polonium and to a lower degree also the β activity of bismuth. When the surface is scraped, the layer of the material near the surface is plastically deformed. Generated defects facilitate the diffusion of polonium and bismuth radioisotopes to the surface where the thermodynamic potential is lower than inside the material.