Composition containing a hafnia phosphor of enhanced luminescence
AssigneeEastman Kodak Company
InventorsPhilip S. Bryan, Patrick M. Lambert, Christine M. Towers, Gregory S. Jarrold
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Abstract
An intensifying screen for producing a latent image in a silver halide radiographic element when imagewise exposed to X-radiation is disclosed. The screen contains a phosphor having a hafnia host containing zirconia in concentrations higher than those found in optical grade hafnia. The phosphor can include as an activator one or a combination of titanium, rare earth, and alkali metal ions. Phosphor preparation processes are also disclosed.
Claims14
A composition containing a phosphor capable of absorbing X-radiation and emitting longer wavelength electromagnetic radiation which is comprised of monoclinic crystals of a hafnium dioxide phosphor host consisting essentially of oxygen and elements satisfying the relationship
- Hf.sub.1-z Zr.sub.z M.sub.y
- wherein
- M represents at least one alkali metal;
- y is in the range of from 6.times.10.sup.-4 to 1.0;
- and
- z is in the range of from 4.times.10.sup.-4 to 0.3. said phosphor exhibiting a higher luminescence intensity when excited by X-radiation as compared to the phosphor as described above absent M.
A composition containing a phosphor capable of absorbing X-radiation and emitting longer wavelength electromagnetic radiation which is comprised of monoclinic crystals of a hafnium dioxide phosphor host consisting essentially of oxygen and elements satisfying the relationship
- Hf.sub.1-z Zr.sub.z M.sub.y Ti.sub.x
- wherein
- M represents alkali metal ions;
- x is in the range of from 3.times.10.sup.-4 to 0.5;
- y is in the range of from 6.times.10.sup.-4 to 0.2;
- and
- z is in the range of from 4.times.10.sup.-4 to 0.3.
Dependencies are inferred from the claim text.