Measurement of Surface Potential Distribution of Fluorinated Polyimide Film

Metal-Dielectric-Metal structure is widely applied in many pulsed power systems, such as electro-vacuum devices, high power microwave equipment and particle accelerators. This kind of composite insulation is suffered with high gradient electric field, which may result in phenomena of surface flashover across the dielectric. Corresponding surface charges and trap characteristics are important parameters, determining final flashover. This paper is focused on surface charges distribution (SCD) and trap measurement of fluorinated polyimide film, to investigate influences of fluorination on surface potential distribution. Additionally, the treatment methods of fluorination including fluorinated gas proportion and applied time have significant influences on SCD. The improvement of SCD can lead to flashover threshold improvement. These results are effective to illuminate theoretical mechanism of fluorination suppression and optimize the treatment process.