X-Ray image converters utilizing rare earth admixtures
First Claim
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1. An improved multi-layer x-ray screen construction which comprises:
- (a) a photographic film having emulsion layers disposed on each major surface and separated by an optically transparent support,(b) a pair of phosphor layers being positioned on each side of said photographic film to form a sandwich configuration, and(c) each of said phosphor layers comprising an admixture of polyhedral terbium activated gadolinium oxysulfide phosphor crystals having an average particle size in the range of approximately 6 to about 20 micronsin combination with plate-like crystals having an average particle size in the range from approximately 2 to about 12 microns having the general formula;
space="preserve" listing-type="equation">LnOX;
Tm.sup.3+whereinLn is one or more of La and Gd,X is one or more of Cl and Br, andTm is present as an activator ion from about 0.05 to about 1 mole percent,said phosphor admixture exhibiting improved resolution capability and reduced crossover problem.
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Abstract
Various rare earth phosphor admixtures are described utilizing thulium-activated oxyhalides of lanthanum and/or gadolinium to provide improved performance in x-ray image converter devices. These phosphor admixtures are used in radiographic screens in combination with either blue sensitive or green sensitive photographic film.
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Citations
8 Claims
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1. An improved multi-layer x-ray screen construction which comprises:
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(a) a photographic film having emulsion layers disposed on each major surface and separated by an optically transparent support, (b) a pair of phosphor layers being positioned on each side of said photographic film to form a sandwich configuration, and (c) each of said phosphor layers comprising an admixture of polyhedral terbium activated gadolinium oxysulfide phosphor crystals having an average particle size in the range of approximately 6 to about 20 microns in combination with plate-like crystals having an average particle size in the range from approximately 2 to about 12 microns having the general formula;
space="preserve" listing-type="equation">LnOX;
Tm.sup.3+wherein Ln is one or more of La and Gd, X is one or more of Cl and Br, and Tm is present as an activator ion from about 0.05 to about 1 mole percent, said phosphor admixture exhibiting improved resolution capability and reduced crossover problem. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification