Recent measurements of critical supersaturations for the vapor phase homogeneous
nucleation of several substances using a diffusion cloud chamber technique exhibit a
dependence on the pressure of the carrier gas used in the experiments. A model of droplet
growth and motion in a diffusion cloud chamber, combined with the density and temperature
profiles of the chamber is presented to explain the pressure dependent results. The model
demonstrates that at higher carrier gas pressures the growth of the droplets is retarded and …