Abstract: A proximity type image intensifier having an evacuated electrically conductive tube envelope is described. The image intensifier tube includes improved structure for supporting components within the tube envelope. The support structure includes a support ring having a first inwardly extending edge portion which defines a support surface for supporting the component, and a second inwardly extending edge portion which defines a compression surface and component access aperture. The retaining ring includes a planar inner surface and an outer edge surface. The inner surface contacts the component supported in the support ring. The retaining ring is allowed to expand whereupon the outer edge surface engages the support ring compression surface. Radial expansion of the retaining ring creates an axial compression force between the retaining ring inner surface and the support surface about the circumference of the component being supported.