U.S. Philips Corporation

Martinus A Ligtenberg

August L Simons

Johannes K Colditz

Johnny W Van Der Velden

Theodorus F Van Bergen

Franciscus M Dreesen

The entrance screen in an X-ray image intensifier includes an intermediate layer of a material which selectively absorbs photon energy. As a result, the speed of the photo-electrons is substantially reduced, thus improving the imaging. By introducing a radial variation of the absorption in the intermediate layer, vignetting-compensation can also be realized without substantial loss of sensitivity and resolution for the central portion of the tube. The resolution at the periphery of the tube can thus be substantially improved.

X-ray image intensifier tube comprising a selective filter

Vapor deposition crucible is provided at least twenty degrees from the central normal to a smooth surface of a screen on which luminescent material is to be deposited. During deposition the surface is rotated relative to the source to produce a layer having a regular structure and a good fill factor.

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Heerlen, Netherlands

Martinus A Ligtenberg