Extrusion of macrocrystal scientillation phosphors
AssigneeHarshaw/Filtrol
InventorsKing H. Rosette, Herbert Packer
Life of this patent
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Abstract
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.
Claims5
A scintillation phosphor formed by extrusion of a cleavable macrocrystal melt-grown starting material selected from an alkali metal halide containing an activator and an alkaline earth metal halide containing an activator, said extrusion being affected at a temperature in excess of one-half the melting point of said macrocrystal, measured in degrees centigrade, but below its melting point, at a pressure sufficient to force said macrocrystal through an orifice which is smaller in cross section than the cross section of said macrocrystal so as to form a fully dense, entirely polycrystalline scintillator extrudate having grains in a size range from about 10 microns to about 1 centimeter, said extrudate being further characterized by:
- being at least twice as strong and resistant to shock and less subject to cleavage than the macrocrystal starting material;
- having essentially the same or better scintillation properties decay time and light disseminating efficiency as said macrocrystal, being free from intergranular or intercrystalline voids on a macroscopic scale greater than about 100 times the interatomic distances within the crystal lattice structure;
- and being pervious to the wavelength of the light generated as a result of the impact of ionizing radiation within the crystal.
Dependencies are inferred from the claim text.