WO2007004099A1 - Gd2o2s: pr pour ct avec une remanence tres courte provoquee par l'utilisation de yb en tant que capteur de eu - Google Patents

Gd2o2s: pr pour ct avec une remanence tres courte provoquee par l'utilisation de yb en tant que capteur de eu Download PDF

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WO2007004099A1
WO2007004099A1 PCT/IB2006/052050 IB2006052050W WO2007004099A1 WO 2007004099 A1 WO2007004099 A1 WO 2007004099A1 IB 2006052050 W IB2006052050 W IB 2006052050W WO 2007004099 A1 WO2007004099 A1 WO 2007004099A1
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detector
ceramic material
preferred
fluorescent ceramic
ppm
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Cornelis Reinder Ronda
Günter ZEITLER
Herbert Schreinemacher
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Philips Intellectual Property & Standards Gmbh
Koninklijke Philips Electronics N.V.
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    • G21K4/00—Conversion screens for the conversion of the spatial distribution of X-rays or particle radiation into visible images, e.g. fluoroscopic screens
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    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/547—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on sulfides or selenides or tellurides
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    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
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    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
    • C09K11/7766—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals
    • C09K11/7767—Chalcogenides
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    • C09K11/7771—Oxysulfides
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
    • C09K11/7783—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals one of which being europium
    • C09K11/7784—Chalcogenides
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3224—Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/54—Particle size related information
    • C04B2235/5418—Particle size related information expressed by the size of the particles or aggregates thereof
    • C04B2235/5436—Particle size related information expressed by the size of the particles or aggregates thereof micrometer sized, i.e. from 1 to 100 micron
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/656—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes characterised by specific heating conditions during heat treatment
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/658—Atmosphere during thermal treatment
    • C04B2235/6581—Total pressure below 1 atmosphere, e.g. vacuum

Definitions

  • Gd 2 O 2 S Pr for CT with a very short afterglow due to the use of Yb as a scavenger for Eu.
  • the present invention is directed to a Gadolinium containing powder contaminated with Europium as well as a fluorescent ceramic contaminated with Europium.
  • the invention further relates to a method for manufacturing a fluorescent ceramic using single-axis hot pressing.
  • the invention still further relates to a detector for detecting ionizing radiation.
  • the invention still further relates to a use of said detector for detecting ionizing radiation.
  • Fluorescent members for detecting high energy radiation contain a phosphor that can absorb the radiation and convert it into visible light.
  • the luminescent emission thereby generated is electronically acquired and evaluated with the assistance of light sensitive systems such as photodiodes or photomultipliers.
  • Such fluorescent members can be manufactured of single-crystal materials, for example, doped alkali halides.
  • Non-single-crystal materials can be employed as powdered phosphor or in the form of ceramic members manufactured there from.
  • a typical fluorescent ceramic material employed for detecting high energy radiation is doped Gd 2 O 2 S.
  • Gd 2 O 2 S is doped with Europium (Eu), which can result in an undesirable increased afterglow characteristics.
  • Eu Europium
  • a first object of the present invention is to provide a scintillating ceramic containing Europium with very short afterglow characteristics.
  • a Gd 2 O 2 S: M fluorescent ceramic material with a very short afterglow whereby M represents at least one element selected from the group Pr, Tb, Dy, Sm, Ce and/or Ho and the Gd 2 O 2 S: M fluorescent ceramic material comprises additionally:
  • the inventors have found out that surprisingly the drawbacks of a contamination of Gd 2 O 2 S with Eu can be overcome or at least significantly reduced when the Gd 2 O 2 S comprises Ytterbium. It is believed that the role of the Yb is at least to a great deal as follows:
  • part of the metal M in the Gd 2 O 2 S which is usually present in the form of trivalent ions is oxidized as represented by the equation I:
  • the Yb serves in a way as a "scavenger" for the Eu.
  • the Yb will then subsequently react - correspondingly to the reaction of Eu as seen in equation III - as shown in equation V: h + + Yb 2+ -> Yb 3+ + hv ( « 970 nm) (V)
  • the emission lies in a different wavelength area, this can be filtered away without harming the performance behaviour of the ceramic material.
  • the content of Yb is in a ratio of Yb to Eu (in wt:wt) of > 0.001: 1 to ⁇ 10000 : 1.
  • the Yb will not serve as a scavenger any more, when the content is higher, undesired side reactions will take place (as will be described further below).
  • a Gd 2 O 2 S: M fluorescent ceramic material with a very short afterglow is provided whereby M represents at least one element selected from the group Pr, Tb, Dy, Sm, Ce and/or Ho and the Gd 2 O 2 S: M fluorescent ceramic material comprises additional:
  • M represents at least one element selected from the group Pr, Tb, Dy, Sm, Ce and/or Ho.
  • M represents Praseodymium (Pr).
  • Yb ions can be carried out using aqueous solutions of corresponding salts: YbCl 3 , YbBr 3 , YbI 3 , Yb(NO 3 ) 3 , Yb 2 (SO 4 ) 3 etc.
  • the introduction of dopant ions can be carried out during a mechanical mixture of Gadolinium containing powders, such as Gd 2 O 2 S, with insoluble compositions comprising the dopant, like oxides, for example Yb 2 O 3 .
  • Gadolinium containing powders such as Gd 2 O 2 S powder, may be mechanically mixed with water insoluble salts of Yb, like YbF 3 , Yb 2 S 3 , Yb 2 O 2 S, Yb 2 (CO 3 ) 3 , Yb 2 (C 2 O 4 ) 3 and the like.
  • the doped pigment powder OfGd 2 O 2 S has a surface according to BET in the range of > 0.01 m 2 /g and ⁇ 1 m 2 /g, preferably of > 0.05 m 2 /g and ⁇ 0.5 m 2 /g and more preferably of > 0.1 m 2 /g and ⁇ 0.2 m 2 /g.
  • Gadolinium containing powders like Gd 2 O 3 , are used for the manufacture Of Gd 2 O 2 S: M fluorescent ceramic materials.
  • the process for the preparation OfGd 2 O 3 and OfGd 2 O 2 S: M fluorescent ceramic materials is complex and time consuming. However, the characteristics with respect to afterglow and other physical properties cannot be altered arbitrarily for the fluorescent ceramic material once prepared.
  • the amount of: - Europium is > 0.05 wt. ppm and ⁇ 1 wt. ppm, preferably of > 0.1 wt. ppm and ⁇ 0.5 wt. ppm, based on Gd 2 O 2 S, and/or
  • Ytterbium is > 0.05 wt. ppm and ⁇ IOOO wt. ppm, preferably > 0.05 wt. ppm and ⁇ 500 wt. ppm
  • Europium can be contained as Eu 3+ , preferably as salt, for example EuCl 3 , EuF 3 , Eu 2 O 2 S, Eu 2 (CO 3 ) 3 , Eu 2 (C 2 O 4 ) 3 , and the like.
  • the content of Yb is in a ratio of Yb to Eu (in wt:wt) of > 0.01 : 1 to ⁇ 1000 : 1, preferably > 0. 1 : 1 to ⁇ 100 : 1 and most preferred > 1: 1 to ⁇ 10 : 1. These margins have been shown in practice to be the best suitable ratios of Yb to Eu (in wt:wt).
  • the content of Yb is in a ratio of M to Yb (in wt:wt) of > 0.001 : 1 to ⁇ 10000 : 1, preferably >0.01 : 1 to ⁇ 1000: 1, more preferred > 0.1 : 1 to ⁇ 100 : 1 and most preferred > 1: l to ⁇ lO : 1.
  • M being the sum of content(s) of the metals Pr, Tb, Dy, Sm, Ce and/or Ho in the Gd 2 O 2 S.
  • the content of Yb (Pr in ratio to Yb) according to a preferred embodiment of the present invention is (in wt:wt) of > 0.001 : 1 to ⁇ 1000 : 1, preferably > 0.01: 1 to ⁇ 100 : 1 and most preferred > 0.1: 1 to ⁇ 100 : 1.
  • the Pr 3+ concentration in Gd 2 O 2 S is between > 10 and ⁇ 2000 wt. ppm, preferably > 100 to ⁇ 1000 wt. ppm and most preferred > 500 to ⁇ 1000 wt. ppm. These margins have shown in practice to be suitable in order with the present invention.
  • a Gd 2 O 2 S: M fluorescent ceramic material according to the present invention as described above exhibits an afterglow of > 0 ppm at 0.5s and ⁇ 80 ppm at 0.5s and preferably > 17 ppm at 0.5s and ⁇ 20 ppm at 0.5s.
  • a Gd 2 O 2 S: M fluorescent ceramic material exhibits an afterglow of > 0 ppm at 0.5s and ⁇ 50 ppm at 0.5s, preferably > 5 ppm at 0.5s and ⁇ 40 ppm at 0.5s, further preferred > 10 ppm at 0.5s and ⁇ 30 ppm at 0.5s and more preferred > 15 ppm at 0.5s and ⁇ 25 ppm at 0.5s.
  • a Gd 2 O 2 S: M fluorescent ceramic material according to the present invention exhibits a relative light yield in the range of > 120% and preferably more than 230% of the light output OfCdWO 4 .
  • Light output and afterglow was measured with a Hamamatsu PMT and a National Instruments ADC, whereby the photomultiplier is shielded against direct irradiation by lead shield.
  • the afterglow was measured with 120 kV / 100 mA, 80 cm FDD (18-20 mGy/s), 2 s pulse, whereby all afterglow values are given in ppm of stationary signal.
  • the signal values (light output) were measured on 4 x 4 mm 2 pixels, silicone glued to a photodiode.
  • the afterglow is measured after the X-ray pulse has been switched off.
  • the Gd 2 O 2 S: M fluorescent ceramic material is transparent. It should be noted that the Gd 2 O 2 S: M fluorescent ceramic material can be yellow colored in case that Ce is present.
  • the transmission of the Gd 2 O 2 S: M fluorescent ceramic material at the wavelength of own emission at about 515 nm is 10% to 70%, preferably 20% to 60% and more preferred > 40% and most preferred > 50%, with respect to a layer thickness of 1.6 mm.
  • the measurements of total transmission were carried out using a Perkin Elmer spectrometer.
  • a further object of the present invention is directed to a Gadolinium containing pigment powder useful in the manufacture of a Gd 2 O 2 S: M fluorescent ceramic material according to the present invention.
  • the inventors have surprisingly found that a Gd 2 O 2 S: M fluorescent ceramic material with reduced afterglow can be obtained if a Gadolinium containing pigment powder is used which contains Yb as described above.
  • the Gadolinium containing pigment powder can be selected from the group comprising Gd 2 O 3 , Gd 2 O 2 S and/or Gd 2 O 2 S : M, wherein M represents at least one element selected from the group Pr, Tb, Dy, Sm, Ce and/or Ho.
  • the Gadolinium containing pigment powder is contaminated with Europium, such as Eu 3+ , of > 0.05 wt. ppm to ⁇ 1 wt. ppm based on Gd 2 O 2 S.
  • the Gadolinium containing pigment powder comprises > 0.05 wt. ppm Eu 3+ to ⁇ 1 wt. ppm Eu 3+
  • the amount of Yb, such as Yb 3+ , added to said powder is according to a preferred embodiment of the present invention > 0.05 wt. ppm Yb to ⁇ 1000 wt. ppm Yb, preferably > 0.5 wt. ppm Yb to ⁇ 100 wt. ppm Yb, preferably > 1 wt. ppm Yb to ⁇ 10 wt. ppm Yb, based on said Gd 2 O 2 S.
  • the ratio of Yb to Eu is adjusted to > 0.001 : 1 to ⁇ 10000 : 1, preferably > 0.01: 1 to ⁇ 1000 : 1, more preferably ⁇ 0. 1: 1 to ⁇ 100 : 1 and most preferred > 1 : 1 to ⁇ 10 : 1.
  • the Gadolinium containing pigment powder has a powder grain size of 1 ⁇ m to 20 ⁇ m
  • a further object of the present invention is directed to a method for the manufacture of a Gadolinium containing pigment powder contaminated by Europium to be used in the manufacture of a Gd 2 O 2 S: M fluorescent ceramic material according to the present invention.
  • the method for the manufacture of a Gadolinium containing pigment powder contaminated by Europium to be used in the manufacture of a Gd 2 O 2 S: M fluorescent ceramic material with very brief afterglow comprises the steps: a) detecting the amount of Europium in said Gadolinium containing pigment powder b) adding Yb, preferably in such a way that the ratio of Yb to Eu is adjusted to > 0.001: 1 to ⁇ 10000 : 1, preferably > 0.01: 1 to ⁇ 1000 : 1, more preferably > 0. 1: 1 to ⁇ 100 : 1 and most preferred > 1 : 1 to ⁇ 10 : 1.
  • the amount of Europium, for example Eu 3+ is less then 0.05 wt. ppm or less then 0.01 wt. ppm based on Gd 2 OiS, Yb may be added to the Gd 2 O 2 S only in minute amounts.
  • the method according to the present invention provides measures to avoid the manufacture OfGd 2 O 2 S: M (GOS) fluorescent ceramic materials having an undesired sustained afterglow.
  • M fluorescent ceramic materials having an undesired sustained afterglow.
  • Suitable Europium, such as Eu 3+ , contaminated Gadolinium containing pigment powders can be selected from the group comprising Gd 2 O 3 , Gd 2 O 2 S and/or Gd 2 O 2 S : M
  • Gadolinium containing pigment powders as mentioned below are often contaminated with Europium, such as Eu 3+ , it is suggested by the inventors to detect the quantitative amount of Europium in said Gadolinium containing pigment powder.
  • the amount of Europium for example, the amount OfEu 3+
  • the amount of Europium can be measured by use of optical spectroscopy. It is most preferred for Eu 3+ contaminated Gadolinium containing pigment powder to detect the amount of Eu 3+ based on optical spectroscopy which measure the emission intensity of Eu 3+ (excitation at about 254 nm UV radiation).
  • An optical spectroscopy method which measures the emission intensity of Eu 3+ allows an accurate determination of the Eu 3+ content down to concentrations in the sub ppm range for an Eu 3+ contaminated Gadolinium containing pigment powder.
  • the emission radiation of Europium, such as Eu 3+ , contaminated Gd 2 O 3 precursor powder at excitation at 254 nm UV - obtained from a low pressure Hg- discharge - radiation provides a red colored visible radiation.
  • Emission spectra of Europium, such as Eu 3+ , contaminated Gd 2 O 2 S : M powders show an emission radiation amongst others in the range of 620 nm to 630 nm.
  • the concentration OfEu 3+ is given in wt. ppm based on Gd 2 O 2 S.
  • Ytterbium preferably as Yb 3+ , for example YbCl 3
  • YbCl 3 is added, preferably in such a way that the ratio of Yb to Eu is adjusted to > 0.001 : 1 to ⁇ 10000 : 1, preferably > 0.01: 1 to ⁇ 1000 : 1, more preferably > 0. 1: 1 to ⁇ 100 : 1 and most preferred > 1: 1 to ⁇ 10 : 1.
  • the content of Yb in the Gd 2 O 2 S material is preferably > 0.05 and
  • ⁇ 10000 ppm preferably >0.05 and ⁇ 1000, more preferably > 0.1 and ⁇ 100 ppm and most preferred >1 and ⁇ 10 ppm.
  • the analysis of the Gadolinium containing powder with respect to the concentration Of Eu 3+ has the advantage that amount of Yb, which is preferred according to the present invention, can easily be maintained simply by adding a suitable Yb source such as YbCl 3 .
  • a suitable Yb source such as YbCl 3 .
  • a fourth object of the present invention is directed to a method for the manufacture of a fluorescent ceramic material according to the present invention using hot-pressing, said method comprising the steps: a) selecting a pigment powder of Gd 2 O 2 S : M as described above whereby the grain size of said powder used for hot-pressing is of 1 ⁇ m to 20 ⁇ m, and said hot- pressing is carried out at a temperature of 1000° C to 1400° C; and/or a pressure of 100 MPa to 300 MPa; b) air annealing at a temperature of 700° C to 1200° C for a time period of 0.5 hours to 30 hours, and optional between step a) and step b) an additional step c) is carried out, whereby step c) comprises annealing fluorescent ceramic under vacuum at a temperature of 1000° C to 1400° C for a period of time of 0.5 hours to 30 hours.
  • the pigment powder OfGd 2 O 2 S can comprise an amount of M from 0.1 ppm to 1000 ppm (weight fraction).
  • the pressing mode is at a temperature of 1000° C to 1400° C, preferably of 1100° C to 1300° C, more preferably of 1150° C to 1250° C; and/or - a pressure of 100 MPa to 300 MPa, preferably of 180 MPa to 280 MPa and more preferably of 200 MPa to 250 MPa.
  • the vacuum during the step of uni-axial pressing according to the present invention is ⁇ 100 Pa and > 0.01 Pa.
  • the vacuum can be adjusted in the range of > 0.01 Pa and ⁇ 50 Pa, preferred in the range of > 0.01 Pa and ⁇ 10 Pa and most preferred the vacuum is adjusted to the range of > 0.01 Pa and ⁇ 1 Pa.
  • the fluorescent ceramic after the step of hot-pressing under vacuum, can be further treated by air annealing at a temperature of 700° C to 1200° C, preferably of 800° C to 1100° C, more preferably of 900° C to 1000° C; whereby said time period for air annealing treatment is 0.5 hours to 30 hours, preferably 1 hours to 20 hours, more preferably 2 hours to 10 hours and most preferably 2 hours to 4 hours.
  • Gd 2 O 2 S pigment powder used according to the present invention has an average grain size in the range of 1 ⁇ m to 20 ⁇ m, more preferred of 2 ⁇ m to 10 ⁇ m and most preferred of 4 ⁇ m to 6 ⁇ m.
  • step c) comprises annealing fluorescent ceramic under vacuum at a temperature of 1000° C to 1400° C for a period of time of 0.5 hours to 30 hours.
  • the annealing temperature is selected in the range of 1100° C to 1300° C, more preferably of 1200° C to 1250° C.
  • the time period for vacuum annealing can be preferably set to 1 hour to 20 hours, more preferably to 2 hours to 10 hours and most preferably 3 hours to 5 hours.
  • the present invention further relates to a detector arranged for detecting ionizing radiation, said detector comprising a fluorescent ceramic as described above whereby the detector is preferably an X-ray detector, CT-detector or Electronic Portal Imaging detector .
  • the fluorescent ceramic according to the present invention can be used for example in - a scintillator or fluorescent member for detecting ionizing radiation, preferably x-rays, gamma rays and electron beams; and/or an apparatus or device used in the medical field, preferably for computed tomography (CT).
  • a scintillator or fluorescent member for detecting ionizing radiation, preferably x-rays, gamma rays and electron beams
  • CT computed tomography
  • At least one fluorescent ceramic according to the present invention can be used for a detector or apparatus adapted for medical imaging.
  • the fluorescent ceramic can be used for any detector known in the medical field.
  • detectors are for example X-ray detector, CT-detector, Electronic Portal Imaging detector, and the like.
  • the detector furthermore comprises a filter material which absorbs over the whole wavelength area of > 960 to ⁇ 980 nm.
  • the inventors have found out that in some applications, a fluorescence occurring from the Yb takes place, which is believed to be caused by the mechanism as shown in equations IV and V.
  • This fluorescence is in a different wavelength area than the undesired afterglow occurring from the Eu. Therefore it can be filtered away by using a filter material which absorbs over the whole wavelength area of > 960 to ⁇ 980 nm.
  • the filter material absorbs over the whole wavelength area of > 950 to ⁇ 990 nm, most preferred > 940 to ⁇ 1000 nm.
  • the detector furthermore comprises a filter material which in addition absorbs over the whole wavelength area of >10 keV and ⁇ 200 keV to further shield the radiation sensitive electronics.
  • the electrical detection means in the detectors such as a photo diode will not be harmed by the ionizing radiation, which increases the lifetime of the detector.
  • the filter material absorbs over the whole wavelength area of > 10 keV to ⁇ 200 keV, most preferred > 40 keV to ⁇ 150 keV .
  • the filter material is based on interference, this implies the use of a fulter in which alternatingly materials with low and high refractive indices are used, an example being an interference filter with alternating thin layers of SiO 2 and Ta 2 O 5 or SiO 2 and TiO 2 .
  • the optical thicknesses of these layers are usually a quarter of a given design wavelength or a multiple thereof. Normally the thickness of an interference filter is of the order of a few millimetres.
  • the invention further relates to a method of reducing the afterglow in a Gd 2 O 2 S: M fluorescent ceramic material comprising the following steps:
  • M fluorescent ceramic material in an amount suitable to serve as a scavenger for the reaction of Europium with electrons in the ceramic material, preferably in a ratio of Yb to Eu (in wt:wt) of > 0.001 : 1 to ⁇ 10000 : 1
  • Fig. 1 shows a very schematic cross-sectional view of a detector according to a first embodiment of the present invention
  • Fig. 2 shows a schematic cut-out top-view on the ceramic of Fig. 1 cut approximately at line I-I in Fig. 1.
  • Fig. 1 shows a schematic cross-sectional view of a detector 1 according to a first embodiment of the present invention.
  • the detector comprises a ceramic material 10 as described above, which emits light upon emittance of ionizing radiation.
  • the ceramic material is provided in a brick-like matter to prevent optical cross-talk, which would reduce spatial resolution. It should be noted that all dimensions in Figs. 1 and 2 are highly schematic and the actual size and dimensions in the final applications may be greatly different.
  • the ceramic material Upon absorption of ionizing radiaton, the ceramic material will then itself emit light via fluorescence in the visible wavelength area.
  • This light will then pass the filter material 30, which is made as described above and enter an electric means, such as a photo diode 40, for further processing.
  • ceramic material 10 is covered with a reflector 20 to guide all light towards the photo diode 40.

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  • Inorganic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Structural Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Luminescent Compositions (AREA)

Abstract

L'invention concerne une matière en céramique fluorescente Gd2O2S: M, dans laquelle Yb agit comme un capteur de manière à diminuer une rémanence non souhaitée par contamination Eu dans la matière en céramique fluorescente Gd2O2S: M.
PCT/IB2006/052050 2005-07-05 2006-06-23 Gd2o2s: pr pour ct avec une remanence tres courte provoquee par l'utilisation de yb en tant que capteur de eu WO2007004099A1 (fr)

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Cited By (2)

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Publication number Priority date Publication date Assignee Title
WO2013014557A1 (fr) * 2011-07-28 2013-01-31 Koninklijke Philips Electronics N.V. Scintillateur de détecteur à base de terbium
US9638807B2 (en) 2008-08-07 2017-05-02 Koninklijke Philips N.V. Scintillating material and related spectral filter

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US4421671A (en) * 1982-06-18 1983-12-20 General Electric Company Rare-earth-doped yttria-gadolinia ceramic scintillators
EP0533316A1 (fr) * 1991-06-21 1993-03-24 Kabushiki Kaisha Toshiba Détecteur aux rayons X et système d'examination
US5640016A (en) * 1994-02-25 1997-06-17 Kabushiki Kaisha Toshiba Rare-earth oxysulfide scintillators and X-ray detectors using rare-earth oxysulfide scintillators

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US4421671A (en) * 1982-06-18 1983-12-20 General Electric Company Rare-earth-doped yttria-gadolinia ceramic scintillators
EP0533316A1 (fr) * 1991-06-21 1993-03-24 Kabushiki Kaisha Toshiba Détecteur aux rayons X et système d'examination
US5640016A (en) * 1994-02-25 1997-06-17 Kabushiki Kaisha Toshiba Rare-earth oxysulfide scintillators and X-ray detectors using rare-earth oxysulfide scintillators

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Title
RYOUHEI NAKAMURA: "Improvements in the X-ray Characteristics of Gd2O2S:Pr Ceramic Scintillators", JOURNAL OF THE CERAMIC SOCIETY, vol. 82, no. 9, 1999, pages 2407 - 2410, XP002406282 *
SHIGEO SHIONOYA, WILLIAM M. YEN: "Phosphor Handbook", 1999, CRC PRESS, XP002406284 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9638807B2 (en) 2008-08-07 2017-05-02 Koninklijke Philips N.V. Scintillating material and related spectral filter
WO2013014557A1 (fr) * 2011-07-28 2013-01-31 Koninklijke Philips Electronics N.V. Scintillateur de détecteur à base de terbium
CN103718063A (zh) * 2011-07-28 2014-04-09 皇家飞利浦有限公司 基于铽的探测器闪烁体
US9322935B2 (en) 2011-07-28 2016-04-26 Koninklijke Philips N.V. Terbium based detector scintillator
RU2605518C2 (ru) * 2011-07-28 2016-12-20 Конинклейке Филипс Н.В. Сцинтиллятор на основе тербия для детектора

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