Break down voltage of electrode arrangements in vacuum in consideration of surface area

Today different models exist to explain the mechanism of high voltage breakdown of electrode arrangements in vacuum. Experimental investigations support two empirical approaches: particle and field emission induced breakdown. It should be considered that the experimental results are influenced by electrode material, surface finish, surface area, conditioning of the surface and the geometry of the electrode arrangement. In this work, an empirical relation between the breakdown voltage of the electrode arrangement and the surface area aims to be found. To this purpose, a borda profile is stressed with lightning impulse voltage. The borda profile has the advantage of homogenous field distribution over the whole surface area of the electrode arrangement. Other parameters such as the surface finish or the electrode material are kept constant to receive the same conditions during measurement. Additional measurements with coplanar profiles are also presented. The first results and deliberations for an empirical approach are shown.