Abstract
The paper describes characteristics of charging on a spacer which is shape of cylider and cone. It is known that charged spacer decreases insulation strength for polarity reversal. If charging on a spacer decreases, insulation strength of a spacer will increase for polarity reversal. To prevent charge accumulation, the effects of coating on spacers and electrodes were investigated. Metal sputtering coating on spacers obtained by glow discharge in a low pressure Ar gas decreases surface resistivity. So charge accumulated on a spacer is forced to leak. Dielectric coating on electrodes prevent electron emission from the negative electrode. These coatings prevent a spacer from charging. For a conical spacer, the effects of the normal component of electric field and the electric field line from a conductor were investigated. Combinig these methods, charge accumulation becomes to be minimized.
