Charging processes of fine particles by UV light irradiation

Summary form only given, as follows. It is known theoretically that fine particles are charged by electrons, ions, secondary electron emission, and photoemission. Experiments to clear the charging processes and charge of particle have not been performed enough. It is very important to clear the charging processes in order to understand the phenomena of fine particle plasmas in the laboratory and space, collisions, interaction between particles, and growth of particle size. Also, charging processes are important to planetary ring simulation experiments such as the Saturn in our laboratory. We measured their charge after exposing particles to UV light, electron beam, or gaseous plasmas to find charging processes of particles. The experiments were performed in a vacuum chamber.