High-voltage vacuum tube

High voltage vacuum tube ( 9 ) with an anode ( 3 ) and a cathode ( 4 ), the anode ( 3 ) and/or the cathode ( 4 ) being electrically insulted by means of an annular insulator ( 21/22 ). The annular insulator ( 21/22 ) is designed arched once, humped in direction of the vacuumized inner space ( 6 ), the arch having in the direction of the vacuumized inner space ( 6 ) a sloping front area ( 31 ) and two lateral areas ( 30/33 ). The sloping front area ( 31 ) of the insulator ( 22 ) of the anode ( 3 ) slopes toward the disc center ( 7 ) of the insulator ( 22 ), while the sloping front area ( 31 ) of the insulator ( 21 ) of the cathode ( 4 ) slopes away from the disc center ( 7 ) of the insulator ( 21 ).