New studies on scattering properties of different kinds of soot and carbon-black

New polarization and brightness curves as a function of scattering angle are studied at λ=632.8 and 543.5 nm using PROGRA2 instruments (Propriétés Optiques des Grains Astronomiques et Atmosphériques) for four different kinds of soot and for two samples of carbon-black levitating in the cloud. The soot samples are also studied on the deposited surface. Two of the soot samples are issued from incomplete combustion of Toluene liquid solvent under two different combustion conditions. Two others are issued from a solid polymer. Polymethyl Methacrylate or PMMA under two different combustion conditions. These new studies are done using new more sensitive cameras than previous ones, allowing darker agglomerates to be detected.

Research highlights► Polarization and brightness curves are studied for soot and black-carbon. ► Polarization decreases when primary particle diameter increases (until 50 nm). ► Polarization increases with agglomerate's diameter for soot and for black-carbon. ► Polarization is sensitive to the agglomerate size distribution. ► Brightness curve produced by soot samples show similar behavior.