Evaluation of a factor for calculating SEEA charge on insulator surface in vacuum

A secondary electron emission avalanche occurring on a surface of an insulator of a bridged gap, along with the resultant charging phenomena of the surface, plays a decisive role in the progress of the flashover in a vacuum. This paper reports a method developed to derive a constant that is necessary for calculating the distribution of charge accumulated on the surface due to the secondary electron emission avalanche based on a calculation and a measurement.