Surface Flashover on Printed Circuit Boards in Vacuum under Electron Beam Irradiation

This paper deals with the surface flashover characteristics of dielectric material during electron beam irradiation in vacuum in order to design the conductive patterns on printed circuit boards used inside a spacecraft adequately. The dielectric material and the electrodes printed on it were irradiated with electrons of the energy of 3-10keV. DC high voltage was applied between the two electrodes during electron irradiation. The voltage was increased step-wisely until the surface flashover occurred on the dielectric. We obtained the result that the surface flashover voltage increased with the insulation distance between the electrodes. However, electron irradiation caused the flashover voltage to lower. The flashover voltage characteristics were obtained as parameters of the electrode distance and the energy of the electron beam.