Indirect photoelectric diffusion charging of submicron aerosols

A new method of charging submicron particles in clean inert gases has been developed. Monodisperse sodium chloride aerosols in the diameter range of 10-50 nm were generated as test aerosols. They were charged by the attachment of photoelectrons emitted from different metal surfaces inside the aerosol flow duct. The metal surfaces were irradiated by u.v.-light of 185 or 254 nm wavelength. The influences of particle diameter, particle number concentration, photoemitting material, electrical potential and trace compounds in the carrier gas on the charging efficiency have been investigated.