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US 4,967,085 AGranted
X-ray intensifying screen including a titanium activated hafnium dioxide phosphor containing neodymium to reduce afterglow
AssigneeEastman Kodak Company
InventorsPhilip S. Bryan, Patrick M. Lambert, Christine M. Towers, Gregory S. Jarrold
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Abstract
An intensifying screen is disclosed containing a phosphor composition comprised of monoclinic crystals of a titanium activated hafnia phosphor host containing neodymium ions to reduce afterglow. A phosphor composition in which zirconia is at least partially substituted for hafnia is also disclosed.
Claims12
A screen comprised of
- a support and
- a fluorescent layer containing a phosphor capable of absorbing X-radiation and emitting longer wavelength electromagnetic radiation comprised of monoclinic crystals of a titanium activated hafnium dioxide phosphor host,
- characterized in that the monoclinic crystals consist essentially of oxygen and combined elements satisfying the relationship
- Hf.sub.1-z Zr.sub.2 Ti.sub.x M.sub.y Nd.sub.w
- wherein
- M represents at least one alkali metal;
- w is in the range of from 5.times.10.sup.-8 to 5.times.10.sup.-4 ;
- x is in the range of from 3.times.10.sup.-4 to 1.0;
- y is up to 1;
- and
- z is up to 0.3,
- the phosphor exhibiting reduced afterglow when excited by X-radiation as compared to the phosphor as defined above absent neodymium.
9 more elements
A screen comprised of
- a support and
- a fluorescent layer containing a phosphor capable of absorbing X-radiation and emitting longer wavelength electromagnetic radiation comprised of monoclinic crystals of a titanium activated hafnium dioxide phosphor host,
- characterized in that the monoclinic crystals consist essentially of oxygen and combined elements satisfying the relationship
- Hf.sub.1-z Zr.sub.z Ti.sub.x M.sub.y Nd.sub.w L.sub.v
- wherein
- L is at least one of samarium and europium;
- M represents at least one alkali metal;
- v is in the range of from 1.times.10-6 to 5.times.10-4;
- w is in the range of from 5.times.10.sup.-8 to 5.times.10.sup.-4 ;
- x is in the range of from 3.times.10.sup.-4 to 1.0;
- y is up to 1;
- and
- z is up to 0.3,
- when excited by X-radiation the phosphor exhibiting (a) reduced afterglow as compared to the phosphor as defined above absent neodymium, samarium and europium and (b) higher prompt emission intensity as compared to the phosphor as defined above absent samarium and europium.
11 more elements
Dependencies are inferred from the claim text.