WO1999002622A1 - Phosphore, detecteur de rayonnement et unite de tomographie assistee par ordinateur tous deux equipes dudit phosphore - Google Patents
Phosphore, detecteur de rayonnement et unite de tomographie assistee par ordinateur tous deux equipes dudit phosphore Download PDFInfo
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- WO1999002622A1 WO1999002622A1 PCT/JP1998/003063 JP9803063W WO9902622A1 WO 1999002622 A1 WO1999002622 A1 WO 1999002622A1 JP 9803063 W JP9803063 W JP 9803063W WO 9902622 A1 WO9902622 A1 WO 9902622A1
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Definitions
- the present invention relates to a rare earth oxysulfide phosphor suitable for use as a radiation detector for detecting X-rays, ⁇ -rays, and the like, particularly, a radiation detector such as an X-ray CT device or a positive-port camera. Further, the present invention relates to a radiation detector and an X-ray CT apparatus using the above phosphor.
- a radiation detector used for X-ray CT or the like is a combination of xenon gas chamber or BGO single crystal (bismuth germanate) and a photomultiplier tube, C sl: T 1 single crystal or C d W0 4 single Combinations of crystals and photodiodes have been used, but in recent years rare earth phosphors with high radiation-to-light conversion efficiency have been developed as scintillators, and radiation detectors combining such phosphors and photodiodes have been developed. Has been put to practical use.
- the rare earth phosphor mainly L 2 0 3 (L is Y, elements represent like G a) a rare earth oxide phosphor containing a small amount of active agent as a body (JP 6 4 - 3 8 4 9 producing a 1 JP etc.), L 2 0 2 S a rare earth oxysulfide containing a small amount of active agent as a base material (there is a O key Shisarufuai de) phosphors, the former phosphor those cubic
- it has the advantage of being excellent in transparency, but has the disadvantage that the luminous efficiency is inferior to the latter.
- the luminous efficiency is high, for example in Japanese Patent Publication 6 0 4 8 5 6 No. G d 2 0 2 S: P r, C e, F force, JP-B-5 9- 3 8 2 8 0 No. (Y, G a, L a or L u) 2 0 2 S: T b, the C e is disclosed.
- the emission peak of the phosphor differs depending on the activator (also referred to as an activator).
- the phosphor using Pr as an activator emits green light
- the phosphor using Tb as an activator changes from blue to blue. It emits green light.
- a phosphor containing Eu as an activator emits red light, and is used as a phosphor for color television (Japanese Patent Publication No. 47-132443).
- the properties required of the scintillation materials generally used for radiation detectors include short afterglow, high luminous efficiency, large X-ray stopping power, and chemical stability.
- the afterglow is large, the signal containing information becomes unclear in the time axis direction, and the afterglow is required to be extremely small.
- the afterglow of a phosphor includes primary afterglow and secondary afterglow (long afterglow component).
- Primary afterglow has a relatively short decay time (approximately 2 milliseconds or less), while secondary afterglow has a longer decay time, which is particularly undesirable when phosphors are used for scintillation. .
- the secondary afterglow is large, the signal containing information becomes unclear in the time axis direction.
- Secondary afterglow is considered to be due to electrons or holes thermally released from traps created by lattice defects in the phosphor, which contributed to the emission. Or by adding another additive that substantially reduces the work of the shallow trap.
- the rare earth oxysulfide phosphor described in Japanese Patent Publication No. 60-48556 and using Pr as a light-emitting component can be used as an X-ray CT scintillator by adding Ce. A phosphor has been obtained.
- a detector with higher detector efficiency is desired in order to minimize the irradiation dose received by the human body while maintaining sufficient detector efficiency and a high SN ratio.
- the peak response wavelength of the PIN photodiode currently used as the photodetector of the radiation detector used for X-ray CT etc. is in the red region, but the phosphors using Pr or Tb as the activator are blue or Since the LED emits green light, the wavelength matching of the PIN photodiode is poor, and there is a problem that the overall detection efficiency as a radiation detector is low even if the luminous efficiency is high and the afterglow is small.
- an object of the present invention is to solve these problems of the prior art and to provide a phosphor having extremely low afterglow and high luminous efficiency, particularly a phosphor useful as a scintillator for X-ray CT and the like. And Another object of the present invention is to provide a radiation detector having excellent wavelength matching between a phosphor and a photodetector and having high detector efficiency (light output). Another object of the present invention is to provide an X-ray CT apparatus having a radiation detector with extremely low afterglow and high detector efficiency as a radiation detector and capable of obtaining a high-resolution and high-quality tomographic image. I do. Disclosure of the invention
- the present inventors have conducted intensive studies on rare earth oxysulfide phosphors containing Eu as a light emitting component. As a result, the addition of a predetermined component has a high luminous efficiency and a large amount of secondary afterglow. It has been found that a phosphor with a significantly reduced phosphor content can be obtained, leading to the present invention.
- the phosphor of the present invention is:
- L represents at least one element selected from the group consisting of Gd, La, and Y
- M represents at least one element selected from the group consisting of Tb and Pr
- S r represents at least one element selected from the group consisting of Z n.
- the X is 0.001 ⁇ x ⁇ 0.06, y is 0 ⁇ y ⁇ 12X10_ 5, z is 0 ⁇ z ⁇ 12 X 10- 5 , d has a value ranging from 0 ⁇ d ⁇ 2.5X10_ 4.
- the element L may be any of Gd, La, and Y.
- the force that can use one or more of these elements, the X-ray stopping power when all L positions are replaced with Gd Can be the highest. However, even if a part of Gd is replaced with La or Y, the emission characteristics are almost the same.
- Eu is an element serving as an activator (luminescent component) of the phosphor of the present invention, and its content (X: the number of moles replacing one mole of the element L) is 0.001 or more in order to cause Eu emission. Is preferred. Since the content X of E u can not get twice the light output more than the the C DW0 4 0.06, in applications where high light output is required, the content X of E u is 0.06 or less . More preferably, the content X of Eu is 0.002 to 0.03. This range can be obtained about 2.5 times the light output of the C DW0 4. Elements M and Ce reduce the afterglow of the phosphor of the present invention.
- the element M may be either Tb or Pr, and a part of Tb may be replaced with Pr.
- the effect of reducing afterglow cannot be obtained with only one of the elements M or Ce, and at least one of the elements M and Ce are contained.
- the afterglow reduction effect can be obtained.
- the content of M y and the content of Ce z both increase, the afterglow decreases, but at the same time, the light output of the scintillation tends to decrease, so in applications where high light output is required, preferably it does not exceed 12 X10- 5.
- the light output of more than twice the C DW0 4 is obtained, and when or E u and C e or only E u deer also contain afterglow E u only This can be reduced to a fraction of that in the case where only M is included.
- M ' is not an essential element in the phosphor of the present invention
- the emission of Eu can be increased by adding the element M'.
- One or more of Ca, Sr, and Zn are used as the element M * that increases the emission of Eu.
- Ca has a function of improving the emission of Eu by 7% at the maximum, and is particularly preferable.
- Element M ' is like this, by incorporating within a range of 2.5X10- 4, the effect is obtained. Especially 0.3X10- 4 in the range of ⁇ 2.0X10- 4, it is possible to improve the emission of about 3% or more.
- the crystal form of the phosphor of the present invention is not particularly limited.
- a method of using the phosphor of the present invention as a single crystal a method of single crystallizing another phosphor described in J. Appl. Phys., Vol. 42, p. 3049 (1971) can be applied.
- the phosphor of the present invention is a rare earth oxysulfide, it is necessary to adopt a method for preventing the diffusion of sulfur during the production as a production method, and a hot isostatic pressing method (hereinafter, referred to as a HIP method) ) Is preferred.
- a hot isostatic pressing method hereinafter, referred to as a HIP method
- a sintering aid is added to the raw material powder, This is packed in a container made of pure iron or metal, sealed in a vacuum, and hot isostatically pressed. Li 2 GeF 6 or the like can be used as a sintering aid.
- the conditions for hot isostatic pressing are a temperature of 900 to 1900 ° C, preferably 1100 to 1400 ° C, and a pressure of about 900 to 1800 atm, for about 30 minutes to several hours. Thereby, a phosphor as a dense and highly transmissive sintered body can be obtained.
- the phosphor before the HIP treatment can be prepared as follows. For example Gd 2 0 3, Eu 2 0 3, Na 2 C0 3, formulated S so that a predetermined composition, added trace elements (Tb (P r), C e, Ca , etc.) salts of nitrates added, further appropriate flux component, for example K 3 P 0 4 ⁇ 3 H 2 0, L i 2 B 4 0 7 , such as a packed in ⁇ Ruminarutsubo After the addition, to the lid of the crucible as about 1350 ° C Bake for several hours (3 to: about 10 hours). The scintillating powder thus baked is subjected to the above-mentioned HIP treatment.
- the phosphor after HIP has oxygen or sulfur defects, cut into a desired shape, and then in Ar gas containing a small amount of oxygen at about 1000 ° C to 1300 ° C for about 15 minutes to Desirably anneal for 120 minutes.
- the phosphor thus manufactured is dense, has high translucency, and has little loss due to light scattering, so that a radiation detector having a large light output can be obtained.
- the phosphor of the present invention can be used for general phosphor applications such as papers, fluorescent plates, and scintillators, but X-ray CT detectors that require particularly high emission output and low afterglow are required. It is suitable as.
- the radiation detector of the present invention includes a ceramic scintillator and a photodetector for detecting light emission of the scintillator, and uses the above-described phosphor as the ceramic scintillator.
- a photodiode such as a PIN photodiode or an avalanche photodiode is used as the photodetector.
- These photodiodes have high sensitivity, short response time, and wavelength sensitivity in the range from visible light to near-infrared light, so that wavelength matching with the above-described phosphor of the present invention is well suited.
- the X-ray CT apparatus of the present invention holds an X-ray source, an X-ray detector arranged to face the X-ray source, the X-ray source and the X-ray detector, and A tomographic image of the subject is created based on the rotating body driven in rotation and the X-ray intensity detected by the X-ray detector.
- a radiation detector combining the above-described phosphor and photodiode is used as the X-ray detector.
- a conventional scintillator Ichita e.g., CdW0 4
- the sensitivity compared with the X-ray CT apparatus using the It can be improved about twice and the afterglow is very small, so that high-quality and high-resolution images can be obtained.
- the size of the element can be reduced, an image with high spatial resolution can be obtained. Furthermore, it is possible to reduce the amount of X-ray exposure of the subject compared to conventional X-ray CT equipment.
- FIG. 1 is a diagram showing the configuration of an embodiment of the X-ray CT apparatus of the present invention.
- FIG. 2 is a diagram showing the configuration of an embodiment of the radiation detector (X-ray detector) of the present invention.
- FIG. 6 shows the Tb concentration (y) and Pr concentration of the phosphor of the comparative example. (y) or Ce concentration (z) and shows the relationship between the intensity of the secondary afterglow of the detector
- the phosphor of Figure 7 is the invention (G d ..
- FIG. 1 is a view schematically showing an X-ray CT apparatus according to the present invention.
- the apparatus includes a scanner gantry section 10 and an image reconstructing section 20, and the scanner gantry section 10 has an opening through which a subject is loaded.
- a rotating disk 11 having a section 14, an X-ray tube 12 mounted on the rotating disk 11, and a collimator attached to the X-ray tube 12 for controlling a radiation direction of the X-ray flux.
- X-ray detector 15 mounted on the rotating disk 11 opposite the X-ray tube 13 and the X-ray tube 13 and X-rays detected by the X-ray detector 15 are converted into predetermined signals.
- a scanning circuit 17 for controlling the rotation of the rotating disk 11 and the width of the X-ray flux.
- the image reconstruction unit 20 reconstructs a CT image by processing the measurement data S1 sent from the input device 21 and the detector circuit 16 for inputting the subject's name, examination date and time, examination conditions, etc.
- Image information circuit that adds information such as the subject's name, examination date and time, and examination conditions input from the input device 21 to the CT image created by the image operation circuit 22 and the image operation circuit 22
- a display circuit 24 that adjusts the display gain of the CT image signal S2 to which image information has been added and outputs the display gain to the display monitor 30.
- X-rays are emitted from the X-ray tube 12 while the subject is laid on a bed (not shown) installed in the opening 14 of the scan gantry section 10. .
- This X-ray obtains directivity by the collimator 13 and is detected by the X-ray detector 15.
- the X-ray is rotated by rotating the rotating disk 11 around the subject.
- X-rays are detected while changing the irradiation direction.
- one rotation (360 degrees) of the rotating disk is regarded as one scan, and an image of one cross section is reconstructed from measurement data for one scan.
- the tomographic image created by the image reconstruction unit 20 is displayed on the display monitor 30.
- the X-ray detector 15 is composed of a large number of scintillator elements (for example, 960) that combine a scintillator and a photo diode, and each scintillator is shown in Fig. 2.
- the structure has a combination of the scintillator 151 and the PIN photodiode 152, and the p-layer side of the photodiode 152 is connected to the detection circuit 16.
- the entire device except for the p-layer of the photodiode 152 is covered with a shield 153 so as not to let the light emitted from the scintillator 151 escape to the outside.
- the shield 153 is made of a material that transmits X-rays and reflects light, for example, aluminum.
- the scintillator 151 is a phosphor that absorbs and emits X-rays emitted from the X-ray tube 12 and transmitted through the subject.
- the scintillator 151 is the above-described phosphor of the present invention, that is, a rare earth oxysulfide having Eu as an activator. And contains T b (and / or P r) and C e as afterglow reducing elements Consists of a body.
- a phosphor produced by the HIP method is used.
- This evening 151 has a luminescence output more than twice that of the conventional CdWO 4 etc.
- the PIN photodiode 152 since the luminescence has a strong luminescence peak around 600 nm, the PIN photodiode 152 has a high light sensitivity. It overlaps with the wavelength region and is photoelectrically converted by the PIN photodiode 152 with high efficiency.
- the detector 15 is required to have a high output and a short afterglow. Since the X-ray CT apparatus of the present invention uses a high-output apparatus with little afterglow, a high-quality CT image can be obtained. In addition, since the light output is high, if the image quality is the same, the X-ray dose can be reduced, and the X-ray exposure to the subject can be reduced.
- the X-ray source may be not only an X-ray tube but also a beam type X-ray apparatus that scans X-rays.
- a ceramic scintillator was made. This A detector was constructed by combining this with a photodiode. The detector was placed 20 cm away from the X-ray source (120 KV, 0.5 mA) and its light output was measured.
- Figure 3 shows the results.
- Light output was relatively light output CdW0 4 detector as 1 (hereinafter referred to as the same).
- the light output of the CdWO 4 detector is more than twice the light output of the CdWO 4 detector in the range of Eu concentration X power ⁇ .001 to 0.055, and more than 2.5 times in the range of X force of 0.002 to 0.03. Indicated.
- Example 2
- the intensity of the secondary afterglow is shown relative to the intensity during excitation as 1 (the same applies hereinafter).
- Tb and Ce reduced the secondary afterglow considerably.
- Tb concentration (y) and C e Concentration (z) increase, light output tended to decrease, Tb concentration (y) and C e Concentration (z) respectively 12 X1 (gamma 5 hereinafter and By doing so, the light output could be made twice or more the light output of the CdWO 4 detector.
- Fig. 5 shows the results.
- a detector was constructed by combining this with a photodiode, and the intensity of the secondary afterglow was measured 30 ms after the X-ray excitation was turned off. The results are shown in FIG. 6 (dashed line).
- G d 2 0 3 as raw material, L a 2 0 3, E u 2 0 3, T b ( ⁇ 0 3) 3, C e ( ⁇ 0 3) 3, Yoi the N a 2 C0 3 and S, further flux components the ⁇ 3 ⁇ 0 4 ⁇ 3 ⁇ 2 0 and L i 2 B 4 0 7 was added as to prepare a scintillator Ichita powder was treated in the same manner as in example 1.
- L i 2 G e F 6 0.1 % in the powder of this as a sintering aid carried out in the same manner as in HIP treatment and HIP after Aniru treatment as in Example 1, G d 2 (..90- xyz) L a 0 2 0 2 S:.
- Light output was relatively light output CdW0 4 detector as 1. If E u concentration X is 0. 005, C a concentration d power, the light output becomes maximum around 9X10- 5, 2.5X10- 4 it can be seen that lower than the additive-free exceeds.
- Table 1 summarizes the results of Example 1 and Examples 4 to 7. Table 1
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Inorganic Chemistry (AREA)
- Physics & Mathematics (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Luminescent Compositions (AREA)
- Measurement Of Radiation (AREA)
- Apparatus For Radiation Diagnosis (AREA)
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE69818501T DE69818501T2 (de) | 1997-07-08 | 1998-07-08 | Phosphor und röntgenstrahlendetektor und röntgen-computertomographieeinheit, beide mit diesem phosphor |
US09/462,321 US6340436B1 (en) | 1997-07-08 | 1998-07-08 | Phosphor, and radiation detector and X-ray CT unit each equipped therewith |
EP98931011A EP1028154B1 (en) | 1997-07-08 | 1998-07-08 | Phosphor, and radiation detector and x-ray ct unit each equipped therewith |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18222197A JP3777486B2 (ja) | 1997-07-08 | 1997-07-08 | 蛍光体及びそれを用いた放射線検出器及びx線ct装置 |
JP9/182221 | 1997-07-08 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1999002622A1 true WO1999002622A1 (fr) | 1999-01-21 |
Family
ID=16114470
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP1998/003063 WO1999002622A1 (fr) | 1997-07-08 | 1998-07-08 | Phosphore, detecteur de rayonnement et unite de tomographie assistee par ordinateur tous deux equipes dudit phosphore |
Country Status (5)
Country | Link |
---|---|
US (1) | US6340436B1 (ja) |
EP (1) | EP1028154B1 (ja) |
JP (1) | JP3777486B2 (ja) |
DE (1) | DE69818501T2 (ja) |
WO (1) | WO1999002622A1 (ja) |
Families Citing this family (22)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6093347A (en) * | 1997-05-19 | 2000-07-25 | General Electric Company | Rare earth X-ray scintillator compositions |
JP2001099941A (ja) * | 1999-09-30 | 2001-04-13 | Hitachi Metals Ltd | 放射線遮蔽板、放射線検出器及び放射線遮蔽板の製造方法 |
JP2002309249A (ja) * | 2001-04-13 | 2002-10-23 | Nichia Chem Ind Ltd | 窒化ガリウム蛍光体及びその製造方法 |
DE10121095A1 (de) * | 2001-04-27 | 2002-10-31 | Philips Corp Intellectual Pty | Gasentladungslampe mit Down-Conversion-Leuchtstoff |
US7054408B2 (en) * | 2003-04-30 | 2006-05-30 | General Electric Company | CT detector array having non pixelated scintillator array |
US7180068B1 (en) | 2004-06-09 | 2007-02-20 | Radiation Monitoring Devices, Inc. | Scintillation materials with reduced afterglow and method of preparation |
FR2874021B1 (fr) | 2004-08-09 | 2006-09-29 | Saint Gobain Cristaux Detecteu | Materiau scintillateur dense et rapide a faible luminescence retardee |
RU2410407C2 (ru) * | 2005-04-19 | 2011-01-27 | Конинклейке Филипс Электроникс Н.В. | СПОСОБ ПОЛУЧЕНИЯ Gd2O2S:Pr С ОЧЕНЬ КРАТКОВРЕМЕННЫМ ПОСЛЕСВЕЧЕНИЕМ ДЛЯ КОМПЬЮТЕРНОЙ ТОМОГРАФИИ |
EP1912916A1 (en) | 2005-07-25 | 2008-04-23 | Saint-Gobain Ceramics and Plastics, Inc. | Rare earth oxysulfide scintillator and methods for producing same |
DE102006012946A1 (de) * | 2006-03-21 | 2007-09-27 | Siemens Ag | Strahlungserfassungseinheit für einen Computertomographen |
JP5759374B2 (ja) * | 2008-08-07 | 2015-08-05 | コーニンクレッカ フィリップス エヌ ヴェ | 発光物質及びそれを用いた放射線検出方法 |
US9638807B2 (en) | 2008-08-07 | 2017-05-02 | Koninklijke Philips N.V. | Scintillating material and related spectral filter |
US8872119B2 (en) | 2008-12-30 | 2014-10-28 | Saint-Gobain Ceramics & Plastics, Inc. | Ceramic scintillator body and scintillation device |
CN102317409B (zh) | 2008-12-30 | 2016-01-20 | 圣戈本陶瓷及塑料股份有限公司 | 陶瓷闪烁体本体和闪烁装置 |
WO2010078223A2 (en) | 2008-12-30 | 2010-07-08 | Saint-Gobain Ceramics & Plastics, Inc. | Ceramic scintillator body and scintillation device |
CN102265183A (zh) | 2008-12-30 | 2011-11-30 | 圣戈本陶瓷及塑料股份有限公司 | 闪烁装置以及用于生产陶瓷闪烁体本体的方法 |
FR2964665B1 (fr) * | 2010-09-14 | 2012-10-12 | Pylote | Nanoparticules luminescentes utilisables en tant que marqueurs et procede pour leur preparation |
WO2012066425A2 (en) | 2010-11-16 | 2012-05-24 | Saint-Gobain Cristaux Et Detecteurs | Scintillation compound including a rare earth element and a process of forming the same |
CN103718063B (zh) | 2011-07-28 | 2017-04-26 | 皇家飞利浦有限公司 | 基于铽的探测器闪烁体 |
CN106575534B (zh) * | 2014-08-08 | 2019-03-12 | 东丽株式会社 | 显示构件的制造方法 |
CN105602564B (zh) * | 2016-03-03 | 2017-11-07 | 盐城工学院 | 一种Zn增强的稀土硫氧化物上转换发光材料及制备方法 |
CN112164702B (zh) * | 2020-09-02 | 2022-08-16 | 上海洞舟实业有限公司 | 一种矩阵式射线成像板制备方法 |
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JPS56151376A (en) * | 1980-04-25 | 1981-11-24 | Hitachi Ltd | Radiation detector |
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DE3268395D1 (en) * | 1981-07-23 | 1986-02-20 | Kasei Optonix | Display device |
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JPS5938280A (ja) | 1982-08-27 | 1984-03-02 | Kawasaki Steel Corp | 炭素繊維プリカ−サ−ピツチの製造方法 |
JPS604856A (ja) | 1983-06-22 | 1985-01-11 | Kawasaki Steel Corp | 音響解析による強磁性体材料の靭性・強度非破壊試験方法および装置 |
US4733088A (en) * | 1985-09-02 | 1988-03-22 | Hitachi, Ltd. | Radiation detector |
DE4402260A1 (de) * | 1994-01-26 | 1995-07-27 | Siemens Ag | Verfahren zur Herstellung eines Leuchtstoffs mit hoher Transluzenz |
-
1997
- 1997-07-08 JP JP18222197A patent/JP3777486B2/ja not_active Expired - Fee Related
-
1998
- 1998-07-08 WO PCT/JP1998/003063 patent/WO1999002622A1/ja active IP Right Grant
- 1998-07-08 US US09/462,321 patent/US6340436B1/en not_active Expired - Fee Related
- 1998-07-08 EP EP98931011A patent/EP1028154B1/en not_active Expired - Lifetime
- 1998-07-08 DE DE69818501T patent/DE69818501T2/de not_active Expired - Fee Related
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JPS56151376A (en) * | 1980-04-25 | 1981-11-24 | Hitachi Ltd | Radiation detector |
JPS6454093A (en) * | 1980-04-25 | 1989-03-01 | Hitachi Ltd | Phosphor |
JPS6318286A (ja) * | 1986-07-11 | 1988-01-26 | Hitachi Ltd | 放射線検出器 |
JPH06206769A (ja) * | 1992-07-28 | 1994-07-26 | Siemens Ag | 希土類−オキシスルフィドの高密度シンチレーションセラミックの製法及びレントゲンコンピューター断層撮影用セラミック体 |
Non-Patent Citations (1)
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Also Published As
Publication number | Publication date |
---|---|
JP3777486B2 (ja) | 2006-05-24 |
EP1028154B1 (en) | 2003-09-24 |
JPH1129767A (ja) | 1999-02-02 |
US6340436B1 (en) | 2002-01-22 |
DE69818501D1 (de) | 2003-10-30 |
EP1028154A1 (en) | 2000-08-16 |
DE69818501T2 (de) | 2004-06-24 |
EP1028154A4 (en) | 2001-03-07 |
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