Abstract: A phosphor powder for producing a high resolution phosphor screen and a phosphor screen are provided. The phosphor screen comprises a substrate, an infrared-absorbing layer, and a phosphor layer coated on the infrared-absorbing layer, wherein the phosphor layer comprises a phosphor powder in which a substantial amount of particles in the powder have a particle size as measured in the longest dimension of greater than 0 and less than about 5 microns. The phosphor screen may also comprise a black, infrared-absorbing substrate with the phosphor layer coated on the substrate. The phosphor powder is formed by preparing a phosphor composition, sintering the composition to form ingots, grinding the ingots to form a powder wherein a substantial amount of particles in the powder have a particle size of greater than 0 and less than about 5 microns, reactivating the powder in an inert atmosphere to a temperature of from about 500° C. to about 550° C.

Abstract: Making a phosphor screen by forming a phosphor powder that incorporates strontium, is made up of particles having a long dimension of less than about 5 microns and having superior response time. Slurrying the phosphor powder with a suitable solvent, dispersant, plasticizer and binder. Coating a suitable substate with an infra red absorbing layer. Coating the phosphor containing slurry onto the infra red absorbing layer. Drying the thus produced screen.

Abstract: An apparatus for correcting an X-ray tomographic image is presented, where the tomographic image is created by measuring an X-ray transmission coefficient at each of a plurality of X-ray beam paths through an object to enable reconstructing a tomographic image of the object. There is a device for selecting a plurality of volume averaged voxels along at least one of the X-ray beam ray paths, and for placing contiguous volume averaged voxels in a run length of volume averaged voxels, to make a plurality of run lengths of volume averaged voxels. There is a device for dividing the plurality of run lengths of volume averaged voxels into a plurality of subslices. There is a device, responsive to the plurality of subslices and responsive to the plurality of run lengths of volume averaged voxels, for computing a corrected value of X-ray attenuation coefficient for the X-ray beam ray path.