US4525628A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rare earth ceramic scintillator
Assignee: General Electric Co
•
Filing: 1982-06-18
•
Granted: 1985-06-25
•
Expires: 2002-06-18
Abstract
Abstract An improved scintillator for a solid state radiation detector useful in CT (computed tomography), DR (digital radiography), and related technologies. The scintillator, rather than being grown as a single crystal, is formed by means of hot pressing or sintering, as a polycrystalline ceramic. Rare earth oxides doped with rare earth activators are selected to yield a cubic crystal structure of high density and transmittance, which satisfies radiation detector requirements better than crystals utilized heretofore.
Inventors
- 👤 Frank A. DiBianca
- 👤 Jean-Pierre J. Georges
- 👤 Dominic A. Cusano
- 👤 Charles D. Greskovich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:25
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/50; C04B35/622; C04B35/64; C04B35/645; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7783; C09K11/7784; C09K11/7787; G; G01; G01T; G01T1/00; G01T1/16; G01T1/20; G01T1/202; G01T1/2023; C04B2235/00; C04B2235/02; C04B2235/30; C04B2235/32; C04B2235/3224; C04B2235/3225; C04B2235/65; C04B2235/658; C04B2235/6581; C04B2235/70; C04B2235/74; C04B2235/76; C04B2235/762
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
121 words
In a radiation detector for use with a source of penetrating radiation, a detector array having a plurality of channels for receiving the radiation, the channels each including a scintillator and a photo-responsive means coupled thereto for producing a set of signals related to the radiation detected in the respective channels, the improvement wherein each scintillator comprises a polycrystalline ceramic scintillator crystal for detecting the radiation in the channels, the crystals being formed of a rare earth oxide doped with a rare earth activator to form a cubic crystal structure which scintillates at a predetermined wavelength, the crystal having a porosity no greater than about 0.1% and being substantially optically transparent to efficiently couple the scintillated radiation to the photo-responsive means.
Claim 2
Dependent Claim
121 words
In a radiation detector for use with a source of penetrating radiation, a detector array having a plurality of channels for receiving the radiation, the channels each including a scintillator and a photo-responsive means coupled thereto for producing a set of signals related to the radiation detected in the respective channels, the improvement wherein each scintillator comprises a polycrystalline ceramic scintillator crystal for detecting the radiation in the channels, the crystals being formed of a rare earth oxide doped with a rare earth activator to form a cubic crystal structure which scintillates at a predetermined wavelength, the crystal having a porosity no greater than about 0.1% and being substantially optically transparent to efficiently couple the scintillated radiation to the photo-responsive means.
Claim 3
Dependent Claim
42 words
The improvement as set out in claim 1 wherein the polycrystalline ceramic scintillator crystal has a depth in the direction of the radiation between about 2 and 10 millimeters and a stopping length in the range between about 0.2 and 1.0 millimeters.
Claim 4
Dependent Claim
40 words
The improvement as set out in claim 1 wherein the rare earth oxide is selected from the group consisting of Gd 2 O 3 , Y 2 O 3 , La 2 O 3 and Lu 2 O 3 .
Claim 5
Dependent Claim
29 words
The improvement as set out in either of claims 1 or 3 wherein the rare earth activator is selected from the group consisting of europium, neodymium, ytterbium and dysprosium.
Claim 6
Dependent Claim
28 words
The improvement as set out in claim 1 wherein the rare earth oxide is gadolinium oxide (Gd 2 O 3 ) and the rare earth activator is europium.
Claim 7
Dependent Claim
37 words
The improvement as set out in claim 1 wherein the rare earth oxide is gadolinium oxide (Gd 2 O 3 ) combined with yttrium oxide (Y 2 O 3 ) and the rare earth activator is europium.
Claim 8
Dependent Claim
104 words
In a radiation detector for use with a source of penetrating radiation, an X-ray detector having a plurality of collimated cells for detecting X-radiation projected into the cells and for producing sets of electrical signals to be integrated as a measure of incident radiation, the improvement comprising a plurality of polycrystalline ceramic scintillators in the cells for detecting the radiation impinging thereon, the crystals being formed of a rare earth oxide doped with a rare earth activator to form a cubic crystal structure which scintillates at a predetermined wavelength, the crystal having a porosity no greater than about 0.1% and being substantially optically transparent.
Claim 9
Dependent Claim
104 words
In a radiation detector for use with a source of penetrating radiation, an X-ray detector having a plurality of collimated cells for detecting X-radiation projected into the cells and for producing sets of electrical signals to be integrated as a measure of incident radiation, the improvement comprising a plurality of polycrystalline ceramic scintillators in the cells for detecting the radiation impinging thereon, the crystals being formed of a rare earth oxide doped with a rare earth activator to form a cubic crystal structure which scintillates at a predetermined wavelength, the crystal having a porosity no greater than about 0.1% and being substantially optically transparent.
Claim 10
Dependent Claim
30 words
The improvement as set out in claim 7 wherein the ceramic scintillator has a linear optical attenuation coefficient at said predetermined wavelength of no more than 30 centimeters -1 .
References Cited (Backward Citations)
US3545987A
Cited
US3640887A
Cited
US3666676A
Cited
GB1364008A
Cited
US3842012A
Cited
US4032471A
Cited
US4242221A
Cited
US4224524A
Cited
US4317037A
Cited
US4225653A
Cited
US4421671A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-06-24 | 1988-12-24 | 1989-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-24 | 1992-12-24 | 1993-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-24 | 1996-12-24 | 1997-06-25 | $7700.00 | Window Closed / Lapsed |