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US6458295B1
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Phosphors, and radiation detectors and X-ray CT unit made by using the same
Assignee: Hitachi Healthcare Manufacturing Ltd
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Filing: 1998-12-22
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Granted: 2002-10-01
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Expires: 2018-12-22
Abstract
Abstract A novel phosphor represented by the general formula (Gd 1−x Ce x ) 3 Al 5−y Ga y O 12 (wherein x and y are values falling in the ranges of 0.0005≦x≦0.02, and 0<y<5.) was provided. The phosphor has a high luminous efficiency when Al and Ga are coexistent in the Gd-system phosphor. In particular, the phosphor with the Ga content (y) in the range of 2-3 has a luminous efficiency of twice the conventional phosphor. A radiation detector using this phosphor as ceramic scintillator is capable of obtaining a high luminous output and a very small afterglow.
Inventors
- 👤 Hiromichi Yamada
- 👤 Makoto Sato
- 👤 Ichiro Miura
- 👤 Motomichi Doi
- 👤 Takaaki Kobiki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:15
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7766; C09K11/7774; C04; C04B; C04B35/00; C04B35/01; C04B35/44; C04B35/622; C04B35/64; C04B35/645; C04B2235/00; C04B2235/02; C04B2235/30; C04B2235/32; C04B2235/3201; C04B2235/3205; C04B2235/3215; C04B2235/3217; C04B2235/3224; C04B2235/3225; C04B2235/3227; C04B2235/3229; C04B2235/3286; C04B2235/44; C04B2235/442; C04B2235/443; C04B2235/444; C04B2235/445; C04B2235/448; C04B2235/70; C04B2235/72; C04B2235/74; C04B2235/76; C04B2235/762; C04B2235/764
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
57 words
A phosphor obtained by press molding a starting material powder and sintering the molded material, and represented by the general formula (Gd 1−z−x L z Ce x ) 3 Al 5−y Ga y O 12 wherein L represents La or Y, and x, y and z are values falling in the ranges of 0.0005≦x≦0.02, 0<y<5, and 0<z<0.2.
Claim 2
Dependent Claim
57 words
A phosphor obtained by press molding a starting material powder and sintering the molded material, and represented by the general formula (Gd 1−z−x L z Ce x ) 3 Al 5−y Ga y O 12 wherein L represents La or Y, and x, y and z are values falling in the ranges of 0.0005≦x≦0.02, 0<y<5, and 0<z<0.2.
Claim 3
Dependent Claim
67 words
A phosphor obtained by baking a starting material powder with flux components to obtain scintillator powder, press molding the scintillator powder, and sintering the molded material, and represented by the general formula (Gd 1−z−x L z Ce x ) 3 Al 5−y Ga y O 12 wherein L represents La or Y, and x, y and z are values falling in the ranges of 0.0005≦x≦0.02,0<y<5, and 0≦z<0.2.
Claim 4
Dependent Claim
67 words
A phosphor obtained by baking a starting material powder with flux components to obtain scintillator powder, press molding the scintillator powder, and sintering the molded material, and represented by the general formula (Gd 1−z−x L z Ce x ) 3 Al 5−y Ga y O 12 wherein L represents La or Y, and x, y and z are values falling in the ranges of 0.0005≦x≦0.02,0<y<5, and 0≦z<0.2.
Claim 5
Dependent Claim
13 words
The phosphor of claim 2 , wherein the flux components are potassium compounds.
Claim 6
Dependent Claim
48 words
The phosphor of claim 3 , wherein the potassium compound is selected from a group of potassium sulfate, potassium nitrate and potassium carbonate. 5 .The phosphor of claim 2 ,wherein the phosphor contains potassium in an amount of 10 wtppm or more but no more than 500 wtppm.
Claim 7
Dependent Claim
25 words
The phosphor of claim 3 , wherein the phosphor contains potassium in an amount of 10 wtppm or more but no more than 500 wtppm.
Claim 8
Dependent Claim
25 words
The phosphor of claim 4 , wherein the phosphor contains potassium in an amount of 10 wtppm or more but no more than 500 wtppm.
Claim 9
Dependent Claim
62 words
A radiation detector comprises a ceramic scintillator and a photodetector for detecting scintillator emission, wherein said ceramic scintillator comprises a phosphor represented by the general formula (Gd 1−z−x L z Ce x ) 3 Al 5−y Ga y O 12 wherein L represents La or Y, and x, y and z are values falling in the ranges of 0.0005≦x≦0.02, 0<y<5, and 0<z<0.2.
Claim 10
Dependent Claim
62 words
A radiation detector comprises a ceramic scintillator and a photodetector for detecting scintillator emission, wherein said ceramic scintillator comprises a phosphor represented by the general formula (Gd 1−z−x L z Ce x ) 3 Al 5−y Ga y O 12 wherein L represents La or Y, and x, y and z are values falling in the ranges of 0.0005≦x≦0.02, 0<y<5, and 0<z<0.2.
Claim 11
Dependent Claim
13 words
The radiation detector of claim 8 , wherein the photodetector is a photodiode.
Claim 12
Dependent Claim
73 words
An X-ray CT apparatus comprising an X-ray source, an X-ray detector disposed facing the X-ray source, a revolving unit for holding the X-ray source and the X-ray detector and revolving them about the object to be examined, and image reconstruction means for reconstructing a tomographic image of the object based on the intensity of the X-rays detected by the X-ray detector, wherein the X-ray detector is a radiation detector of claim 8 .
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