Numerical design of HV insulators based on charge accumulation in vacuum

A MCS (Monte Carlo simulation) method of charge accumulation based on the SEEA (secondary emission electron avalanche) mechanism is applied to the design of effective corrugation on an insulator surface used in vacuum. The electric field distribution on the cathode in the vicinity of a triple junction is analyzed taking the SEEA charge accumulation into account. Considerable relaxation of field strength takes places due to negative charge accumulation with appropriate corrugation. The flashover voltage obtained experimentally increases as the field strength decreases. The results of the MCS agree well with experiment.