Process for producing a scintillator screen
AssigneeThomson-CSF
InventorsJean-Pierre Galves, Jean-Marie Gutierrez
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Abstract
In an X-ray image intensifier consisting of a scintillator screen associated with a photocathode, an electron-optical system and an output screen on which a strong visible image appears, resolution is improved by providing the scintillator screen, formed by a layer of cesium iodide doped with sodium deposited onto the substrate, a structure of needles approximately micrometers in diameter which are kept in the form of separate needles during the subsequent heat treatment by virtue of the presence of silicon oxide in the cesium iodide lattice.
Claims8
A process for the production of a scintillator screen having a substrate and a scintillator layer comprising the steps of keeping the substrate cold, while alternately depositing the vapor condensation cesium iodide doped with sodium and then an oxide and then alternating the deposition of the cesium iodide doped with sodium and the oxide until (a) the desired thickness of the scintillator layer is reached and (b) the deposited layer has a structure of fine needles substantially perpendicular to the substrate and optically independent from one another;
- and then heat treating the substrate and deposited layer to between 250.degree. to 500.degree. C., said oxide introduced into the crystal lattice of the cesium iodide doped with sodium during the chemical vapor deposition step prevents the needles from coalescing into crystals of larger size during said subsequent heating step.
Dependencies are inferred from the claim text.