A cooling arrangement for an electron collector of an electron beam tube has a plurality of solid dielectric spacers surrounding the corrector with an electrically insulative and thermally conductive dielectric liquid in gaps between the spacers. A water cooling system is arranged in thermal contact with the spacers and the liquid dielectric to provide cooling by water circulation. The cooling arrangement is a hybrid of oil and water cooling systems in which the electrically non conductive oil is arranged in gaps between dielectric spacers, the dielectric spacers provide a support for the surrounding water coolant system and ordinary water may be used to be pumped through the water cooling system.