Abstract: The object of the present invention is to provide a radioactive-ray image tube having less deformations, such as the twist of an input substrate, less aberration over the entire regions of an output image, excellent resolution and good brightness uniformity and contrast characteristics. This radioactive-ray image tube 1a comprises an input window 10 formed on one side surface of a vacuum vessel 2a and allowing radioactive-rays to enter the vacuum vessel 2a, an input screen 5 for converting the radioactive-rays incident on the input window 10 into a fluorescent image or a photoelectric image, and an input substrate 4a holding the input screen 5, is characterized in that the input substrate 4a comprises of a clad material 13 having an aluminum alloy material 11 on the radioactive-ray incidence side and a pure aluminum material 12 on the input screen 5 side provided integrally with each other.

Abstract: The present invention assures a satisfactory adhesiveness of an input screen 13 of an X-ray image intensifier, high resolution of an output image and brightness uniformity as required, by configuring an aluminum or aluminum alloy substrate 21 so to have a concave surface with minute irregularities of the substrate material removed by burnishing, excepting gentle irregularities 21c without directivity which are caused by pressing. The gentle irregularities 21c of the substrate 21 preferably have an average length L in a range of 50 &mgr;m to 300 &mgr;m between the neighboring bottoms and an average height H in a range of 0.3 &mgr;m to 4.0 &mgr;m from peaks to bottoms. The invention improves resolution with light on the substrate surface suppressed from being scattered, and decreases image noises which are caused by the minute irregularities.