US4747973A
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Rare-earth-doped yttria-gadolina ceramic scintillators
Assignee: General Electric Co
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Filing: 1986-07-11
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Granted: 1988-05-31
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Expires: 2006-07-11
Abstract
Abstract Rare-earth-doped, polycrystalline yttria-gadolinia ceramic scintillators with high density, optical clarity, uniformity, cubic structure and which are useful in the detection of x-rays, include one or more of the oxides of rare earth elements Eu, Nd, Yb, Dy, Tb, and Pr as activators. The ceramic scintillator may also include CaO, SrO, and Yb 2 O 3 as afterglow reducers. Sintering, sintering combined with gas hot isostatic pressing, and hot pressing methods for preparing the ceramic scintillators are also described.
Inventors
- 👤 Dominic A. Cusano
- 👤 Charles D. Greskovich
- 👤 Frank A. DiBianca
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:46
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/16; G01T1/20; G01T1/202; G01T1/2023; C; C04; C04B; C04B35/00; C04B35/50; C04B35/505; C04B35/622; C04B35/64; C04B35/645; C04B35/6455; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7783; C09K11/7784; C09K11/7787
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
100 words
A high density polycrystalline ceramic scintillator of cubic crystal structure consisting essentially of between 5 mole percent and 50 mole percent Gd 2 O 3 , and between about 0.02 and 12 mole pecent of at least one rare-earth activator oxide selected from the group consisting of Eu 2 O 3 , Nd 2 O 3 , Yb 2 O 3 , Dy 2 O 3 , Tb 2 O 3 , and Pr 2 O 3 ; the remainder being Y 2 O 3 , said scintillator having an optical attenuation coefficient of less than 100 cm -1 .
Claim 2
Dependent Claim
100 words
A high density polycrystalline ceramic scintillator of cubic crystal structure consisting essentially of between 5 mole percent and 50 mole percent Gd 2 O 3 , and between about 0.02 and 12 mole pecent of at least one rare-earth activator oxide selected from the group consisting of Eu 2 O 3 , Nd 2 O 3 , Yb 2 O 3 , Dy 2 O 3 , Tb 2 O 3 , and Pr 2 O 3 ; the remainder being Y 2 O 3 , said scintillator having an optical attenuation coefficient of less than 100 cm -1 .
Claim 3
Dependent Claim
28 words
The polycrystalline ceramic scintillator of claim 1 wherein said rare-earth activator oxide consists essentially of between about 1 and 6 mole percent of Eu 2 O 3 .
Claim 4
Dependent Claim
28 words
The polycrystalline ceramic scintillator of claim 1 wherein said rare-earth activator oxide consists essentially of between about 0.05 and 1.5 mole percent of Nd 2 O 3 .
Claim 5
Dependent Claim
28 words
The polycrystalline ceramic scintillator of claim 3 wherein said rare-earth activator oxide consists essentially of between about 0.1 and 0.5 mole percent of Nd 2 O 3 .
Claim 6
Dependent Claim
27 words
The polycrystalline scintillator of claim 1 wherein said rare-earth activator oxide consists essentially of between about 0.05 and 3 mole percent of Tb 2 O 3 .
Claim 7
Dependent Claim
27 words
The polycrystalline ceramic scintillator of claim 1 wherein said rare-earth activator oxide consists essentially of between 0.1 and 2 mole percent of Yb 2 O 3 .
Claim 8
Dependent Claim
28 words
The polycrystalline ceramic scintillator of claim 1 wherein said rare-earth activator oxide consists essentially of between about 0.03 and 1 mole percent of Dy 2 O 3 .
Claim 9
Dependent Claim
28 words
The polycrystallline ceramic scintillator of claim 1 wherein said rare-earth activator oxide consists essentially of between about 0.02 and 0.05 mole percent of Pr 2 O 3 .
Claim 10
Dependent Claim
35 words
The polycrystalline ceramic scintillator of any one of claims 1, 2, 3, 4, 5, 6, or 8 wherein said Gd 2 O 3 is present in an amount of between 20 and 40 mole percent.
Claim 11
Dependent Claim
22 words
The polycrystalline ceramic scintillator of claim 9 wherein said scintillator has a density of at least about 98 percent of theroretical value.
Claim 12
Dependent Claim
70 words
A high density polycrystalline ceramic scintillator consisting esssentially of between 5 and 50 mole percent of Gd 2 O 3 , 0.5 to 12 mole percent of the activator Eu 2 O 3 , and 0.1 and 2 mole percent of the activator Yb 2 O 3 , the remainder being Y 2 O 3 , said scintillator having an optical attenuation coefficient of less than 100 cm -1 .
Claim 13
Dependent Claim
70 words
A high density polycrystalline ceramic scintillator consisting esssentially of between 5 and 50 mole percent of Gd 2 O 3 , 0.5 to 12 mole percent of the activator Eu 2 O 3 , and 0.1 and 2 mole percent of the activator Yb 2 O 3 , the remainder being Y 2 O 3 , said scintillator having an optical attenuation coefficient of less than 100 cm -1 .
Claim 14
Dependent Claim
27 words
The polycrystalline ceramic scintillator of claim 11 wherein said rare-earth activator consists essentially of between about 1 and 6 mole percent of Eu 2 O 3 .
Claim 15
Dependent Claim
28 words
The polycrystalline ceramic scintillator of claim 11 or 12 wherein the content of Gd 2 O 3 in said scintillator is between about 20 and 40 mole percent.
Claim 16
Dependent Claim
122 words
A high density polycrystalline ceramic scintillator consisting essentially of between 5 to 50 mole percent of Gd 2 O 3 , between about 0.02 and 12 mole percent of at least one rare-earth activator selected from the group consisting of Eu 2 O 3 , Nd 2 O 3 , Yb 2 O 3 , Dy 2 O 3 , Dy 2 O 3 Tb 2 O 3 , and Pr 2 O 3 , and between about 0.1 and 2 mole percent of each of at least one afterglow reducer selected from the group consisting of CaO and SrO, the remainder being Y 2 O 3 , said scintillator having an optical attenuation coefficient of less than 100 cm -1 .
Claim 17
Dependent Claim
122 words
A high density polycrystalline ceramic scintillator consisting essentially of between 5 to 50 mole percent of Gd 2 O 3 , between about 0.02 and 12 mole percent of at least one rare-earth activator selected from the group consisting of Eu 2 O 3 , Nd 2 O 3 , Yb 2 O 3 , Dy 2 O 3 , Dy 2 O 3 Tb 2 O 3 , and Pr 2 O 3 , and between about 0.1 and 2 mole percent of each of at least one afterglow reducer selected from the group consisting of CaO and SrO, the remainder being Y 2 O 3 , said scintillator having an optical attenuation coefficient of less than 100 cm -1 .
Claim 18
Dependent Claim
27 words
The polycrystalline ceramic scintillator of claim 14 wherein said rare-earth activator consists essentially of between about 1 and 6 mole percent of Eu 2 O 3 .
Claim 19
Dependent Claim
27 words
The polycrystalline ceramic scintillator of claim 14 wherein said rare-earth activator consists essentially of between about 0.05 and 1.5 mole percent of Nd 2 O 3 .
Claim 20
Dependent Claim
26 words
The polycrystalline ceramic scintillator of claim 16 wherein said rare-earth activator consists essentially of between about 0.and 0.5 mole percent of Nd 2 O 3 .
Claim 21
Dependent Claim
27 words
The polycrystalline ceramic scintillator of claim 14 wherein said rare-earth activator consists essentially of between about 0.05 and 3 mole percent of Tb 2 O 3 .
Claim 22
Dependent Claim
27 words
The polycrystalline ceramic scintillator of claim 14 wherein said rare-earth ativator consists essentially of between about 0.1 and 2 mole percent of Yb 2 O 3 .
Claim 23
Dependent Claim
27 words
The polycrystalline ceramic scintillator of claim 19 wherein said rare-earth activator consists essentially of between about 0.15 and 0.7 mole percent of Yb 2 O 3 .
Claim 24
Dependent Claim
27 words
The polycrystalline ceramic scintillator of claim 14 wherein said rare-earth activator consists essentially of between about 0.03 and 1 mole percent of Dy 2 O 3 .
Claim 25
Dependent Claim
27 words
The polycrystalline ceramic scintillator of claim 14 wherein said rare-earth acitvator consists essentially of between about 0.02 and 0.05 mole percent of Pr 2 O 3 .
Claim 26
Dependent Claim
38 words
The polycrystalline ceramic scintillator of any one of claims 14, 15, 16, 17, 18, 19, 20, 21, or 22 wherein the content of Gd 2 O 3 in said scintillator is between about 20 and 40 mole percent.
Claim 27
Dependent Claim
27 words
The polycrystalline ceramic scintillator of claim 1, 11 or 14 wherein said scintillator has a density in excess of at least 98 percent of the theoretical value.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-05-31 | 1991-11-30 | 1992-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-31 | 1995-11-30 | 1996-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-31 | 1999-11-30 | 2000-05-31 | $7700.00 | Window Closed / Lapsed |