X-ray scattering studies of the generation of carbon nanoparticles in flames and their transition from gas phase to condensed phase

The dynamics of particle formation were investigated for a diffusion-like ethylene flame containing a cooling metal plate on which particles condensed. Small-angle and wide-angle X-ray scattering techniques were combined to follow size- and structural changes of the soot particles using a new detector. The high dynamic range allowed continuous monitoring from the gas to the condensed phase of the gradually growing layer depositing on the plate. Different stages in the process of particle formation were observed. In addition the sub-nanometer structure of the deposited material changed rapidly as the flame was turned off. The detection system and methodology presented are of general interest since they can be further developed and applied to the study of reactive systems for materials processing in gas- and condensed phases.