Claims
- 1. A process for the preparation of a photostimulable phosphor, comprising:
- (a) preparing a slurry containing BaF.sub.2, BaBr.sub.2 and a europium halide, wherein the amount of BaBr.sub.2 is at least equal to that required stoichiometrically to form BaFBr;
- (b) agitating said slurry for a time sufficient to permit essentially of all of said BaF.sub.2 to react with said BaBr.sub.2 to form BaFBr;
- (c) spray drying the resulting slurry of step b) under conditions that produce porous spheroidal agglomerates having an average diameter larger than that of a preselected diameter;
- (d) firing said spheroidal agglomerates in an inert atmosphere for about 10 to about 120 min. at a temperature of about 650.degree. C. to about 800.degree. C.;
- (e) cooling the fired material of step (d) to ambient temperature in an inert atmosphere;
- (f) washing the cooled material of step (e) with a solvent capable of selectively dissolving any excess BaBr.sub.2 ;
- (g) drying the washed material of step (f) to produce a free flowing powder of the BaFBr:Eu phosphor;
- (h) heat treating the phosphor of step (g) at a temperature of about 850.degree. C. to about 950.degree. C. for about 1/2 to about 15 hours in an atmosphere comprising nitrogen and about 1 to about 2% oxygen to yield an oxygen-containing photostimulable phosphor of the formula Ba.sub.1-x Eu.sub.x FBR.sub.1-2y O.sub.y .phi..sub.y, wherein .phi. represents an anion vacancy, x is about 0.001 to about 0.05, and is about 0.0001 to about 0.01.
- 2. A phosphor produced by the process of claim 1.
- 3. A process for the preparation of a photostimulable phosphor, comprising heat treating a europium-doped barium fluorohalide phosphor at about 850.degree. C. to about 950.degree. C. for about 1/2 to about 15 hours in an otherwise inert atmosphere comprising nitrogen and from about 1% to 2% oxygen sufficient to create an anion vacancy resulting from the removal of an amount of halide atoms sufficient to produce a phosphor of the formula Ba.sub.1-x Eu.sub.x FBR.sub.1-2y O.sub.y .phi..sub.y, wherein .phi. represents an anion vacancy, x is about 0.001 to about 0.05, and y is about 0.0001 to about 0.01.
- 4. A phosphor produced by the process of claim 3.
- 5. In an X-ray image storage panel comprising a substrate and a layer of a photostimulable phosphor, the improvement comprising a phosphor produced by the process of claim 1.
- 6. In an X-ray image storage panel comprising a substrate and a layer of a photostimulable phosphor, the improvement comprising a phosphor produced by the process of claim 3.
Parent Case Info
This is a division of application Ser. No. 07/717,453, filed Jun. 19, 1991, now U.S. Pat. No. 5,227,254.
US Referenced Citations (12)
Foreign Referenced Citations (1)
Number |
Date |
Country |
083085 |
Jul 1983 |
EPX |
Non-Patent Literature Citations (3)
Entry |
A. L. Stevels et al., Phillips Research Reports, 30:277 (1975). |
F. K. Koschnick et al., Physical Review Letters, 67:3571 (1991). |
H. von Seggern et al., J. Appl. Phys., 64(3):1405 (1988). |
Divisions (1)
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Number |
Date |
Country |
Parent |
717453 |
Jun 1991 |
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