A radiation generator comprising a radiation source, a high voltage tank assembly to energize the radiation source and a power circuit configured to supply alternating current (AC) power to the high voltage tank assembly is provided. The high voltage tank assembly comprises a voltage multiplier assembly configured to include a printed circuit board comprising multiple slots, plurality of electrical components configured to be mounted on the printed circuit board and at least one insulating cover with multiple projections configured to be placed on one of the first surface and the second surface of the printed circuit board. Further, the projections of the insulating cover are configured to fit into the slots of the printed circuit board. The projections when fitted into the slots provide insulation barrier to the electrical components mounted on the printed circuit board.