Siemens Aktiengesellschaft

Ulrich Kroener

Walter Greschat

Peter Roemer

In an examplary embodiment wherein the x-ray image, converted into an electron image, is intensified through acceleration in the electrical field, in at least two stages which are inter-coupled via an intermediate screen, such screen contains, as significant elements, a cathodoluminescent layer and a photocathode layer which is optically in contact with the latter. Of these, the one is disposed on the one side and the other is disposed on the opposite side of a satisfactorily stable carrier plate which allows the light of the cathodoluminescent layer to pass through. In the case of this intermediate screen it is difficult to keep the surface sufficiently clean for the purpose of applying the photocathode layer. To this end, the disclosure provides that the surface of the carrier plate be coated with a coating which is resistant to the photocathode layer, which coating, for a photocathode layer of cesium antimony, can be comprised of cesium iodide and be 5 and 10 .mu.m thick. Thus a tight (or sealed) covering of the base and a clean surface are obtained. An x-ray image intensifier improved in accordance with the disclosure is particularly suited for use in medical x-ray diagnostics.

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Forchheim, Germany

Ulrich Kroener