E.i. Dupont De Nemours and Company

William J Zegarski

David B Hedden

Theodore P Christini

Reid E Kellogg

William D Bills

Richard B Maynard

An X-ray evaluation apparatus of a film in cooperation with an intensifying screen with improved resolution at a constant coating weight and speed comprises a phosphor-binder layer coated on a support, wherein the phosphor comprises a rare earth tantalate phosphor in which 5-80% has a tabular morphology with an average aspect ratio of about 2:1 and the remainder of the phosphor has a polyhedral morphology.

X-ray intensifying screens with mixed morophology phosphors

An improved flux for use in preparing X-ray phosphors comprises an alkali metal sulfate, an alkali metal metaborate and, a strontium halide. By varying the concentration of the metaborate and strontium halide in the flux composition, the size and dry bulk density of the phosphor particles and the speed of the phosphor, respectively, can be controlled. Also disclosed is a process of making phosphors using the above flux, and X-ray intensifying screens containing such phosphors.

Flux for phosphor particle size control

An improved flux for use in preparing X-ray phosphors comprises an alkali metal sulfate, an alkali metal metaborate and, optionally a strontium halide. By varying the concentration of the metaborate and strontium halide in the flux composition, the size and dry bulk density of the phosphor particles and the speed of the phosphor, respectively, can be controlled. Also disclosed is a process of making phosphors using the above flux, and X-ray intensifying screens containing such phosphors.

Process of making tantalate X-ray phosphors

An X-ray intensifying screen with improved resolution at a constant coating weight and speed comprises a phosphor-binder layer coated on a support, wherein the phosphor comprises a rare earth tantalate phosphor in which 5-80% has a tabular morphology with an average aspect ratio of about 2:1 and the remainder of the phosphor has a polyhedral morphology.

X-ray intensifying screens with mixed morphology phosphors

A process for preparing X-ray intensifying M' monoclinic tantalate phosphors by firing precursor oxides in a novel flux mixture of alkali metal sulfate/alkali metal or alkaline earth chloride/alkali metal metasilicate. Tantalate phosphors made in this manner have improved X-ray to light conversion efficiency. X-ray intensifying screens made from these phosphors have improved speed and can be used with good results with a plurality of X-ray film elements.

Process of preparing tantalate X-ray intensifying phosphors with

An X-ray intensifying screen made from a mixture of yttrium tantalate and lanthanum oxyhalide phosphors is described. This screen, when used to expose a silver halide element, e.g., conventional grain or tabular grain element, will produce superior image resolution compared to similar screens made using single phosphors alone.

Mixed phosphor x-ray intensifying screens with improved resolution

A process for preparing X-ray intensifying M' monoclinic tantalate phosphors by firing precursor oxides in a novel flux mixture containing a compound capable of producing an alkali metal oxide and an effective amount of an alkali metal metasilicate. Tantalate phosphors made in this manner have improved efficiency and purity. X-ray intensifying screens made from these phosphors have improved speed and can be used with good results with a plurality of X-ray film elements.

An improved X-ray intensifying screen element containing a topcoat layer comprising an acrylonitrile-styrene copolymer optionally mixed with a carboxylated acrylic polymer and an active, phosphor layer having an adhesion promoting amount of a soluble, inorganic salt as described. The improved element exhibits strong adhesion between the topcoat and active layers and is eminently suitable for the rough handling encountered when these elements are used in autochangers and the like.

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Towanda, PA, United States of America

William J Zegarski