Particle size distribution of 7Be-aerosols formed in high energy accelerator tunnels

Abstract The 7 Be, produced by nuclear spallation reactions in the air of high energy accelerator tunnels, is present in the form of an aerosol. The size distribution of the 7 Be-aerosols was measured with a parallel plate diffusion battery and was found to be a log-normal distribution with a geometric mean radii of 27 nm and a logarithmic standard deviation of 0.36. The formation of the 7 Be-aerosol is adequately explained by the attachment of 7 Be to non-radioactive aerosols containing sulfates, which are produced by radiation induced oxidation reactions of SO 2 present in the air.