EXPERIMENTAL-DETERMINATION OF THE ATTACHMENT COEFFICIENTS OF ATOMS AND IONS ON MONODISPERSE AEROSOLS

The attachment coefficients of 212Pb atoms and ions were measured for aerosols in the diameter range 0.1-5 μm. The attachment of the Tn-decay products to the aerosol was carried out in laminar flow through a cylindrical tube. Under the same experimental conditions (but without aerosols) the diffusion coefficient of the atoms was determined. The generation of the monodisperse di-2-ethylhexyl sebacate (DEHS) aerosol was carried out by controlled condensation of vapour upon nuclei. The aerosols had standard deviations of 3-5%. The aerosol size distributions and concentrations were determined by means of an aerosol size spectrometer, which measured the intensity of the scattered light from single particles or droplets. The experimental results agree well with the values of the diffusion attachment theory based on the kinetic theory of gases with the assumption of a sticking probability of the Pb atoms, S = 1. © 1979.