A low cost image intensifier tube is provided which has an improved vacuum sealing mechanism and improved optical transmission. Glass windows on both the input and output of the tube are vacuum sealed within the housing by a ring of indium that contacts the interface between each of the windows and the housing. A pair of raised pointed flanges each positioned along the inner housing surface interfacing the windows protrude into the adjacent ring of indium for improving the vacuum seal of both input and output windows and for controlling the spacing of the elements within the tube. Sealing the photocathode from the rest of the tube is a ceramic cathode cork. The cathode cork is a solid sealing ring press fit within the tube housing and colocated between the input window at the outer edge of the photocathode and the microchannel plate.