Extremely Low Secondary Electron Emission from Metal/DielectricParticulate Coatings
We have studied the SEY behaviour of a particulate coating composed of a mixture of a metal (aluminum) in solid state contact with a particulate dielectric material (polyimide thermosetting resin). Surface charging, roughness, and volume fraction are utilized as the main parameters to characterize the electron emission behaviour. Apart from the important role played by surface composition in the SEY, the influence of the dielectric volume fraction has demonstrated to be critical to achieve a significant reduction of SEY. it was found that E1 of the particulate sample increased with increasing dielectric volume fraction. An extremely high first crossover energy, E1>1000eV, was obtained after the gold metallization of the metal/dielectric coatings of 0.75 dielectric volume fraction. It is also remarkable that SEY was ~0.2 for E<1000 >eV, the true secondaries appear to be reabsorbed.