Abstract
The particle size distributions of radioactive nuclides formed in accelerator beam line tunnels were measured by using a diffusion battery and were found to be log-normal with a geometric mean radius of about 28 nm. The radioactive aerosol formation was well explained by a simple physical adsorption of radioactive nuclides to the ambient non-radioactive aerosols. The fractions of aerosol and gaseous components were measured for individual nuclides formed in the air of a high-energy accelerator tunnel. The formation of these 11C and 13N species was explained by their hot-atom reactions and subsequent chemical reactions.
