Abstract: Sufficient dielectric strength needs to be ensured for the high voltage connection (13-11) of the high voltage electrical equipment such as a pattern generation system for focused ion beam processing and observation (1), without enlarging the equipment. The present invention seals an insulating liquid (13-113a) or gas (13-113b) in the space (13-113) between the connection bushing on the power supply side (13-111) and the flange on the power receiving side (13-112), and applies the water repellent treatment (13-111c) to a surface of the connection bushing or flange on the power receiving side, which the surface faces the space (13-113). Such a configuration provides compact electrical equipment with high dielectric strength, which can prevent the condensation or moisture absorption on the insulation surface in the space of the high voltage connection and can prevent the leakage current increase even under high humidity environment.

Abstract: Sufficient dielectric strength needs to be ensured for the high voltage connection (13-11) of the high voltage electrical equipment such as a pattern generation system for focused ion beam processing and observation (1), without enlarging the equipment.