The Harshaw Chemical Company

Harshaw/filtrol

King H Rosette

Herbert Packer

Ionic salts containing minor amounts of an activator and useful as scintillation phosphors are formed by extrusion of a macrocrystal of either a single crystal or a melt-grown multiple crystal ingot at a temperature below its melting point and under sufficient pressure to form a fully dense, homogeneous polycrystalline mass, the scintillation properties of which are essentially the same as, or better than, those of the original macrocrystal.

Extrusion of macrocrystal scientillation phosphors

A polycrystalline shaped article useful as a light-transmitting body or scintillation phosphor is formed from an essentially moncrystalline melt-grown macrocrystal ingot by pressing the ingot between opposed surfaces with no radial restraint, at a temperature below its melting point and under sufficient pressure to transform the ingot, in situ, into a fully dense, homogeneous, polycrystalline mass of unrestricted width. A polycrystalline shaped article useful as a light-transmitting and/or light-generating body may also be formed from a fully dense, homogeneous, optically integral polycrystalline mass by pressing the polycrystalline mass between opposed surfaces with no radial constraint, at a temperature below its melting point, but greater than one-half its melting point measured in degrees centigrade, under sufficient pressure to form a relatively larger polycrystalline mass of lesser height.

Shaped press-forged normally frangible inorganic crystals

Scintillation phosphors, infrared and ultraviolet transmitting shaped articles of unrestricted length and arbitrary cross section are formed by multiple extrusion of a relatively small single crystal, melt-grown macrocrystal ingot, or, re-extrusion of a relatively small, fully dense polycrystalline parent mass at a temperature below its melting point and under sufficient pressure to form a fully dense, homogeneous polycrystalline mass. A re-extrudate of a first extrudate is wider in cross section than the parent single crystal, or the first extrudate, yet the scintillation, infrared and ultraviolet transmission properties of the polycrystalline re-extrudate are essentially the same or better than those of the parent single crystal or polycrystalline first extrudate. A polycrystalline re-extrudate is disclosed which is optically the same as, but structurally different from a single crystal or first extrudate. It is both optically and structurally different from a hot-pressed or extruded powder. The unique crystalline structure of the re-extrudate is distinguishable from either a first extrudate of a single crystal, or a hot-pressed or extruded powder by its characteristic scatter of a 6328A Laser beam.

Multiple extrusion of polycrystalline extrudates

A polycrystalline shaped article useful as a light-transmitting body or scintillation phosphor is formed from an essentially monocrystalline melt-grown macrocrystal ingot by pressing the ingot between opposed surfaces with no radial restraint, at a temperature below its melting point and under sufficient pressure to transform the ingot, in situ, into a fully dense, homogeneous, polycrystalline mass of unrestricted width. A polycrystalline shaped article useful as a light-transmitting and/or light-generating body may also be formed from a fully dense, homogeneous, optically integral polycrystalline mass by pressing the polycrystalline mass between opposed surfaces with no radial constraint, at a temperature below its melting point, but greater than one-half its melting point measured in degrees centigrade, under sufficient pressure to form a relatively larger polycrystalline mass of lesser height. Wherever trace impurities in the order of about one part per million are detrimental, as in a scintillation phosphor, or where it is essential that a theoretically fully dense material, with no voids, be formed, as for example in a laser window, no method, other than press-forging a fully dense crystalline mass will suffice. In particular, windows may be press-forged which permit the transmittance of laser beams with less than 0.1% absorption, or no more absorption than is displayed by the archetype monocrystalline ingot, whichever is greater. In addition, press-forged windows are characterized by several times greater strength than that obtained with essentially single crystal ingots. Similarly, optically integral scintillation phosphors may be formed having large diameters which are theoretically not limited by the size of the largest essentially monocrystalline ingot which may be grown.

Growing community of inventors

Chagrin Falls, OH, United States of America

King H Rosette