US4647781A
Expired / Lapsed
US
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Gamma ray detector
Assignee: Resonac Corp
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Filing: 1985-10-15
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Granted: 1987-03-03
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Expires: 2005-10-15
Abstract
Abstract A gamma ray detector suitable for use in a positron CT and others is disclosed which comprises a scintillator formed of a single crystal of cerium activated gadolinium silicate which is expressed by a general formula Gd 2 (1-x-y) Ln 2x Ce 2y SiO 5 (where Ln indicates at least one element selected from a group consisting of yttrium and lanthanum, and x and y lie in ranges given by formulae 0≦x≦0.5 and 1×10 -3 ≦y≦0.1).
Inventors
- 👤 Kazumasa Takagi
- 👤 Tokuumi Fukazawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:45
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/29; G01T1/2914; G01T1/2985; G01T1/16; G01T1/20; G01T1/2002; G01T1/202
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
56 words
A gamma ray detector comprising: a scintillator formed of a single crystal of cerium activated gadolinium silicate, said cerium activated gadolinium silicate being given by a general formula Gd 2 (1-y) Ce 2y SiO 5 (where y lies in a range given by formula 1×10 -3 ≦y≦0.1); and a photodetector for detecting light from said scintillator.
Claim 2
Dependent Claim
56 words
A gamma ray detector comprising: a scintillator formed of a single crystal of cerium activated gadolinium silicate, said cerium activated gadolinium silicate being given by a general formula Gd 2 (1-y) Ce 2y SiO 5 (where y lies in a range given by formula 1×10 -3 ≦y≦0.1); and a photodetector for detecting light from said scintillator.
Claim 3
Dependent Claim
26 words
A gamma ray detector according to claim 1, wherein said y in said general formula lies in a range given by a formula 1×10 -3 ≦y≦0.05.
Claim 4
Dependent Claim
60 words
A gamma ray detector for use in positron CT, comprising: a scintillator unit including a single crystal of the formula: Gd 2 (1-y) Ce 2y SiO 5 wherein 1×10 -3 ≦y≦0.1 for receiving gamma rays and emitting luminescence of wavelength 430 mm; a photodetector for detecting said luminescence and generating an electric signal; and means for amplifying said electric signal.
Claim 5
Dependent Claim
60 words
A gamma ray detector for use in positron CT, comprising: a scintillator unit including a single crystal of the formula: Gd 2 (1-y) Ce 2y SiO 5 wherein 1×10 -3 ≦y≦0.1 for receiving gamma rays and emitting luminescence of wavelength 430 mm; a photodetector for detecting said luminescence and generating an electric signal; and means for amplifying said electric signal.
Claim 6
Dependent Claim
25 words
A gamma ray detector for use in positron CT according to claim 3, wherein said scintillator unit has a luminescence decay constant of 60 nanoseconds.
Claim 7
Dependent Claim
19 words
A gamma ray detector for use in positron CT according to claim 4, wherein said photodetector includes a photomultiplier.
Claim 8
Dependent Claim
35 words
A gamma ray detector for use in positron CT according to claim 3, wherein said scintillator unit includes an aluminum case for accommodating said single crystal, which case has an aperture coupled to said photodetector.
Claim 9
Dependent Claim
67 words
A gamma ray detector for use in positron CT according to claim 6, wherein said aluminum casing is provided with a reflective coating on the interior surfaces whereby, upon the gamma rays having passed through the aluminum casing, light is generated within said single crystal scintillator and the light is reflected from said coating and is transmitted through the single crystal to the photodetector via said aperture.
Claim 10
Dependent Claim
25 words
A gamma ray detector for use in positron CT according to claim 3, wherein said single crystal has a (100) crystallographic plane at a surface.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-03-02 | 1990-09-01 | 1991-03-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-02 | 1994-09-01 | 1995-03-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-02 | 1998-09-01 | 1999-03-03 | $7700.00 | Window Closed / Lapsed |