X-ray and ultraviolet luminescence of Li{sub 3}Ta{sub 1{minus}x}Nb{sub x}O{sub 4} prepared by flux synthesis and characterization of a new high efficiency X-ray phosphor
- DuPont Co., Wilmington, DE (United States)
The phase development and luminescence properties, under both X-ray and ultraviolet excitation, of the lithium orthotantalate-lithium orthoniobate system, Li{sub 3}Ta{sub 1{minus}x}Nb{sub x}O{sub 4} for x = 0 to 1, were examined. Using a flux synthesis technique, it was found that the levels of Nb-doping in monoclinic Li{sub 3}TaO{sub 4} and of Ta-doping in cubic Li{sub 3}NbO{sub 4} are higher than previously reported. Under 30 kVp molybdenum X-ray excitation, Li{sub 3}Ta{sub 1{minus}x}Nb{sub 4}O{sub 4} is an efficient blue-emitting phosphor with broadband emission, peaking in the range of 390 to 435 nm. For x = 0 to 0.1, the overall luminescence efficiency is comparable to, or better than, a commercial calcium tungstate, CaWO{sub 4}, Hi-Plus material. The composition Li{sub 3}Ta{sub 0.995}NbO{sub 4} demonstrates an overall luminescence efficiency that makes this phosphor 45% brighter than CaWO{sub 4}Hi-Plus, thereby making it a potentially attractive candidate for use in medical diagnostic imaging systems. Under ultraviolet excitation, broadband blue emission is also observed. For all the Li{sub 3}Ta{sub 1{minus}x}Nb{sub x}O{sub 4} (x > 0) solid solutions, the emission peak maximums agree well with those seen under X-ray excitation and are the result of Nb{sup 5+} emission. 13 refs., 5 figs.
- OSTI ID:
- 679225
- Journal Information:
- Journal of Solid State Chemistry, Vol. 145, Issue 1; Other Information: PBD: Jun 1999
- Country of Publication:
- United States
- Language:
- English
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