WO2015185988A1 - Matériaux d'orthosilicate de terre rare dopé au cérium présentant des défauts destinés à l'amélioration ou aux paramètres de scintillement - Google Patents

Matériaux d'orthosilicate de terre rare dopé au cérium présentant des défauts destinés à l'amélioration ou aux paramètres de scintillement Download PDF

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WO2015185988A1
WO2015185988A1 PCT/IB2015/000949 IB2015000949W WO2015185988A1 WO 2015185988 A1 WO2015185988 A1 WO 2015185988A1 IB 2015000949 W IB2015000949 W IB 2015000949W WO 2015185988 A1 WO2015185988 A1 WO 2015185988A1
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range
crystal
scintillation
ppmw
crystals
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PCT/IB2015/000949
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Alexander Iosifovich Zagumennyi
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Zecotek Imaging Systems Singapore Pte. Ltd
ZAVARTSEV, Yuri Dmitrivech
KUTOVOI, Sergei Alexandrovhich
KOZLOV, Valentin, Alekseevich
Zerrouk, Faouzi Abdelmounaime
ZAVERTYAEV, Mikhail Vasilevich
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Priority claimed from US14/295,301 external-priority patent/US20140291580A1/en
Application filed by Zecotek Imaging Systems Singapore Pte. Ltd, ZAVARTSEV, Yuri Dmitrivech, KUTOVOI, Sergei Alexandrovhich, KOZLOV, Valentin, Alekseevich, Zerrouk, Faouzi Abdelmounaime, ZAVERTYAEV, Mikhail Vasilevich filed Critical Zecotek Imaging Systems Singapore Pte. Ltd
Publication of WO2015185988A1 publication Critical patent/WO2015185988A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B15/00—Single-crystal growth by pulling from a melt, e.g. Czochralski method
    • 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
    • C09K11/7766—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals
    • C09K11/77742—Silicates
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/34—Silicates
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B33/00—After-treatment of single crystals or homogeneous polycrystalline material with defined structure
    • C30B33/02—Heat treatment
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/20—Measuring radiation intensity with scintillation detectors
    • G01T1/202—Measuring radiation intensity with scintillation detectors the detector being a crystal
    • G01T1/2023—Selection of materials

Definitions

  • the present invention relates generally to scintillation substances and, more particularly, to cerium doped oxyorthosilicate materials (crystals and ceramics) having defects for improvement of scintillation parameters such as, for example, short decay time and improved radiation hardness.
  • the present invention also includes related methods of making and using the scintillation materials disclosed herein.
  • x Lu 2( i- X) Si0 5 scintillation crystals have a number of advantages in comparison with other crystals: a high density, a high atomic number, relatively low refractive index, a high light yield, a short decay time of scintillation.
  • the disadvantage of known scintillation material is the large spread of important characteristics of scintillation, namely, a light yield and an energy resolution, from crystal to crystal grown from a single boule.
  • a scintillation decay time (a time of luminescence) may be varied over the wide range of values from 29 nanoseconds to 46 nanoseconds, at that an energy resolution value may fluctuate within the 12%-20% limit.
  • Such a large spread in performance leads up to necessity during an industrial production to grow a large number of boules by Czochralski method, to cut them into parts (packs), to test each pack and on the basis of such tests to select the packs which possibly to utilize for fabrication of scintillation elements for medical tomographs.
  • the concentration of cerium in growing LU2S1O5 crystal is only 22% of cerium ions concentrations in melt. Additional problem is the charge cerium ions: Ce 3+ in crystal and Ce 4+ in the melt.
  • Ce 3+ in crystal and Ce 4+ in the melt In the U.S.A. patent 5,660,627 the crystals 26 mm in diameter were grown at the 0.5 mm/hour and 1 mm/hour rates, however, even at these very advantageous growth parameters, the crystals grown with a conical crystallization front cannot be used for the commercial applications because of low scintillation performance.
  • Claim 2 teaches: Scintillating material based on a silicate crystal comprising lutetium (Lu) and cerium (Ce) characterised in that it contains oxygen vacancy at the quantity not exceeding 0.2 f.u. and its chemical composition is represented by the formula: Lui. y Me y Ai_ x Ce x Si0 5 .
  • A is Lu and at least one element selected from the group consisting of Gd, Sc, Y, La, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, and where Me is at least one element selected from the group consisting of H, Li, Be, B, C, N, Na, Mg, Al, P, S, CI, , Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Rb, Sr, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Cs, Ba, Hf, Ta, W, Re, Os, Ir, Pt , Au, Hg, Tl, Pb, Bi, U, Th, x is a value between l x lO "4 f.u.
  • y is a value between 1 x 10 " 5 f.u. and 0.05 f.u.
  • z is a value between l x l O "5 f.u. and 0.2 f.u.
  • Philips Medical Systems introduced a fully 3 D TOF PET scanner from June 2006, using Ce.LYSO scintillator, having decay time 41 ns; the system timing resolution is about 400 ps.
  • Siemens used Ce:LSO, having decay time about of 40 - 43 ns in all of their clinical PET scanners.
  • the U.S.A. patent 7,65 1 ,632 discloses an inorganic scintillator material of a general formula Lu(2- y - x -z)YyCe x M z Si(i. v )M' v 05 in which: M represents a divalent alkaline earth metal ion and M' represents a trivalent metal.
  • M represents a divalent alkaline earth metal ion
  • M' represents a trivalent metal.
  • the proportions of sum of silicon and trivalent metal ion, Si+M', and oxygen to the remaining elements in the crystal remain constant equal five at all values of x, y, v and z.
  • This limitation results in a violation of the law on preservation of charge neutrality, because the charge neutrality means that the total charge of positive ions must equal the total charge of negative ions in substance.
  • Claim 1 of the U.S.A. patent 7,651 ,632 recites inorganic scintillator materials of unrealizable compositions.
  • the scintillating material having oxygen vacancy and the silicon concentration Sii .oo and a divalent alkaline earth metal ion (including of Mg, Ca, Sr) and a trivalent metal ion (including of Al, In, Ga) it has already been disclosed and claimed in Claim 2 of U.S. Patent No. 6,278,832 to Zagumennyi et al.
  • the diffusing results are increased performance based upon at least a 10% improvement in the energy resolution of the monocrystalline LSO and LYSO body.
  • this inventions need the additional annealing in an ambient containing oxygen at 1 100-1400°C temperatures for the period of time in range of about 30 to 120 hours.
  • the main disadvantage of the above mentioned inventions for the growth of LSO and LYSO crystals the silicon concentration Sii .oo and expensive LU2O3 with the chemical purity 99.99% or 99.998% has been used, in result it is the presence of oxygen vacancies.
  • the second disadvantage is the two steps production technology. Firstly, the long-time growth process and long-time post- grown cooling of large boule.
  • the additional annealing process for oxygen diffusion into the crystalline LSO and LYSO having at least one dimension no greater than 20 mm.
  • the given method can be utilised for improvement of parameters of thin 4x4x30 mm 3 pixels for PET scanners, however this method does not allow reaching the homogeneous and constant scintillating parameters for large size pixels, because; (1) for high energy application in calorimeters optimal LYSO size is 25 x 25 x 280 mm and (2) scintillation crystals size is need about of 75 mm in diameter x 75 mm high for the inspection of trucks and cargo containers for concealed contraband, smuggled goods, and for manifest verification.
  • the U.S.A. patent 7,297,954 teaches a inorganic scintillator has the chemical composition represented by Ce x Ln y Si z O u .where Ln represent at least two elements selected from among Y, Gd and Lu. 0.001 ⁇ x ⁇ 0.1 , 1 .9 ⁇ y ⁇ 2.1 , 0.9 ⁇ z ⁇ 1.1 , 4.9 ⁇ x ⁇ 5.1 , wherein the maximum peak wavelength in the intensity spectrum of emitted fluorescence is a peak in the range between 450 nm and 600 nm.
  • the drawback of this composition characterised by maximum peak wavelength in the range between 450 nm and 600 nm.
  • the Lu 2 SiOs contains 64 ions in an elemental unit, in particular 8 ions of lutetium of the first type (Lui) and eight ions of lutetium of the second type (LU2).
  • the light output, the position of the luminescence maximum and the constant of time for scintillations decay (time of luminescence) depend on the number of Ce 3+ , which substituted ions Lui and/or ions Lu 2 .
  • the centre of luminescence Cei (polyhedron LUO7) has the time of luminescence of 30-38 ns and the position of the luminescence maximum 410-418 um.
  • the centre of luminescence Ce2 (polyhedron LuC ⁇ ) has the time of luminescence of about 50-60 ns and the position of maximum luminescence of 450-520 nm.
  • Ce2 X (Lui_yY y )2(i- x )SiC>5 crystals and a method of making of these crystals are a longitudinal heterogeneity of optical quality of grown crystals, a heterogeneity of the basic scintillation parameters both in a bulk of boule grown by Czochralski method and heterogeneity from boule to boule grown in alike conditions and, at last, a low growth rate.
  • a crystal growth from a stoichiometric composition leads up to that the segregation coefficients of the host crystal components, lutetium (Lu), yttrium (Y), oxygen (O) and the additional component, cerium (Ce), are differed from unit, and, a crystal composition is shifting from melt composition, that results in significant dispersions of light output of a luminescence and radiation hardness for top and bottom a crystal boule despite on the extremely low growth speed.
  • a segregation coefficient of component is a ratio of component's quantity in a crystal to component's quantity in a melt.
  • a technical drawback of known scintillating crystals is the growing of crystals from melting compositions, containing an expensive reagent LU2O3 with the chemical purity 99.99% and 99.998%.
  • the typical high-doped Ce:LSO crystals exhibit the main type of imperfection - the scattering center in middle and very strong in bottom parts of growing crystal boule.
  • the concentration of cerium in growing LU2S1O5 crystal is only 22% of cerium ions concentrations in melt. Therefore, it is not practical commercial production of high optical quality 0.25%Ce:LSO bars with size 25x25x280 mm .
  • the invention is applied to scintillation materials/crystals and may be used for detection of elementary particles and nuclei in high-energy physics, for registrations and measuring of x-ray, gamma- and alpha- radiation in nuclear industry; medicine, Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT), Positron Emission Tomography with Magnetic Resonance imaging (PET/MR); x-ray computer fluorography; non-destructive testing of solid state structure, in a devices having thermal neutron emitter based on neutron generator for the detection of explosive in airport security systems, for the inspection of trucks and cargo containers for concealed contraband, smuggled goods.
  • PET Positron Emission Tomography
  • SPECT Single Photon Emission Computed Tomography
  • PET/MR Positron Emission Tomography with Magnetic Resonance imaging
  • x-ray computer fluorography non-destructive testing of solid state structure, in a devices having thermal neutron emitter based on neutron generator
  • the invention is applied to scintillation crystals for positron emission tomography (PET), which utilizes a radioactive tracer to make images of the distribution of labelled molecules in vivo for different medical targets, for example, (1 ) the whole-body imaging during diagnostic at early stage cancer of a patient in hospitals, (2) the neuro-imaging of human brain.
  • PET is a tool for metabolic imaging that has been utilized since the earliest days of nuclear medicine.
  • An important component of such imaging systems are the detector modules on base of scintillation crystals.
  • the decay time of commercial Ce:GSO, Ce:LSO, Ce.LYSO crystals are 65 ns, 40 ns and 41 ns, respectively.
  • the high density, high light output and short decay time are very important parameters for PET application.
  • the new generation medical PET scanners is a very active area of development two designs: (1 ) for ability to determine how deep in the crystal an event actually occurs (depth of interaction or DOI PET). Pulse shape discrimination based at depth-of-interaction detector designs. The concept is to use two or more layers of crystals that have different light decay times. (2) Other solution is time-of-flight (TOF PET).
  • TOF PET time-of-flight
  • Cerium doped lutetium-based oxyorthosilicate crystal growth is relatively expensive due to the cost of Lu 2 0 3 , having price from US $400/kg of purity 99.9% till US $1500/kg of high purity oxide 99.998%.
  • the growth of one large boule with 90 mm in diameter there is need about 20 kg of L 2O3.
  • the cost of 99.99% LU2O3 is approximately 70% of cost of crystal growth process. Decreasing the cost of one crystal growth process in 2 times and an increase of upper level of impurities ions in scintillated materials on base of low cost LU2O3 is a purpose / an object of the given invention.
  • a task of the given invention is a creation of advanced LFS scintillation material based on a silicate comprising a lutetium (Lu) and cerium (Ce) characterised in that the composition is represented by the chemical formulas:
  • said scintillation material having the high density ⁇ 6.8 -7.4 g/cm 3 , the high light output about 60-95% of Nal(Tl), the one exponential decay constant in the range 12-38 ns for different compositions, the maximum emission of light in the area 400-450 nm, the energy resolution for the full energy peak in the range from 6% till 10%, the high radiation resistance against high energy protons/hadrons, no degradation in optical transmission after gamma-rays irradiation with the dose up to 23 Mrad.
  • composition is represented by the chemical formula (Lu a A b Ce c Si d )i- z Me z J j O q (3)
  • the LFS is a brand name of the set of Ce-doped scintillation materials of the solid solutions on the basis of the rare earth silicate, comprising lutetium and having compositions represented by the chemical formulas:
  • composition is represented by the chemical formula (Lu a A b Ce c Si d )i- 2 e z J j O q (3)
  • Formulas ( 1), (2) and (3) demonstrate that solid solutions are possible for cerium doped lutetium-based oxyorthosilicate scintillation materials.
  • Solid solution is a powders/ceramics/crystals materials, having a defects in comparison with ideal crystal structure.
  • ideal structure the 100 % of Lu 3+ ions located in 100 % position of Lu, the 100 % of Si 4+ ions located in 1 00 % position of Si of ideal crystal structure, the 100 % of oxygen O 2" ions located in 100 % position of oxygen of ideal crystal structure.
  • LFS are scintillation materials having defects in form of the vacancy/or interstitial for Lu ions, or the interstitial/or vacancy for Si ions, the vacancy for oxygen ions. (See Examples of 1 -7). Accordingly, in various embodiments it is desirable to have vacancies, interstitials, or other defects to generate off-stoichiometric scintillation materials.
  • a transformation of the chemical formula of LFS scintillation material into the equivalent chemical formula, having the identical mole ratios of components (Lu+Ce+A+Me)/Si and the identical percents of the oxides, is made by multiplying formula indexes in the formula (1) or (2) at the scaling coefficient.
  • the oxygen vacancies are recited to reflect an accurate value of oxygen in the final crystal solid-state composition.
  • the crystal forms it must obey the conservation of charge neutrality laws, or, in other words, the total positive ions must equal the total negative ions.
  • cerium (IV) oxide initially a Ce 4+ ion
  • the placement of the reduced cerium ion (3 + ) in either the first lutetium's position (Lu l ) or second lutetium's position (Lu2) partially determines the characteristics of the scintillator material (LFS, Ce:LSO , Ce:LYSO, Ce:LGSO), having a monoclinic structure with a space group of C2/c.
  • the structure has two distinct rare earth cation sites. One is a distorted 7-fold coordinate site and the other one is a smaller distorted 6-fold coordinate site. These two sites are quite different from each other, with distinct energy levels for emission.
  • LFS are solid solution of materials having defects in the lattice and significant higher Ce 3+ concentration in a distorted 7-fold coordinate site in comparison with 6-fold coordinate site.
  • a scientific task solved by the present invention is a creation of advanced scintillation materials having emission maximum in the range of about 400 - 450 nm and based on cerium doped a rare-earth oxyorthosilicate including LFS, Ce x Lu 2 -xSi0 5 (LSO), Ce x Lu 2 .x. y YySi0 5 (LYSO), Ce x Lu 2 . x . y Gd y Si0 5 (LGSO) , Ce x Gd 2 .
  • LFS Ce x Lu 2 -xSi0 5
  • LYSO Ce x Lu 2 .x. y YySi0 5
  • LGSO Ce x Lu 2 . x . y Gd y Si0 5
  • x Si0 5 (GSO) crystals having defects in comparison with ideal crystal structure, and said defects change the optical transmission and absorption spectra in the range about of 200-340 nm; and the picks of maximum absorptions located at wavelength ⁇ about of 250-270 nm and ⁇ 2 about of 280-300 nm and ⁇ about of 340-380 nm ; and said maximum absorption picks characterised in that the ratio ⁇ ( ⁇
  • a scientific task solved by the present invention is a creation of advanced scintillation materials having emission maximum in the range of about 400 - 450 nm and based on cerium doped a rare-earth oxyorthosilicate including LFS, LSO, LYSO, LGSO , GSO crystals having defects in comparison with ideal crystal structure, and said defects change the optical transmission and absorption spectra in the range about of 200-340 nm; and the picks of maximum absorptions located at wavelength ⁇ ⁇ about of 250-270 nm and ⁇ 2 about of 280- 300 nm and ⁇ 3 about of 340-380 nm ; and said maximum absorption picks characterised in that the ratio ⁇ ( ⁇ 2 ) / ⁇ ( ⁇ 3 ) > 1.
  • a scientific task solved by the present invention is a creation of advanced scintillation materials having emission maximum in the range of about 400 - 450 nm and based on cerium doped a rare-earth oxyorthosilicate including LFS, LSO, LYSO, LGSO , GSO crystals having defects in comparison with ideal crystal structure, and said defects change the optical transmission and absorption spectra in the range about of 200-340 nm; and the picks of maximum absorptions located at wavelength ⁇ about of 250-270 nm and ⁇ 2 about of 280- 300 nm and about of 340-380 nm ; and said maximum absorption picks characterised in that the ratio ⁇ ( ⁇ ,) / ⁇ ( ⁇ 2 ) > 1.
  • a technical task solved by the present invention is mass production of the large LFS crystalline boules grown from the melt for application in the new generation of electromagnetic calorimetry experiments in high energy physics for search and detection of new elementary particles and nuclei.
  • the scintillation crystals for future collider detector should have the following priority of scintillation properties: (i) high density, (ii) not a radiation damage after irradiations by large doze of gamma-rays and protons, (iii) short decay time, (iv) good energy resolution, (v) homogeneity of scintillation properties at mass production of thousand bars with size up to 25x25x280 mm 3 or at mass production of thousand active plates from size 14x14x2 mm 3 up to 25x25x5 mm 3 of a "Shashlik"-type readout for the High-Luminosity Large Hardron Collider (HL-LHC) at CERN.
  • HL-LHC High-Luminosity Large Hardron Collider
  • the PbWC>4 (Y:PWO) have decay time 10 ns and light output only 0.3% light output of Nal(Tl), but PWO is presently used for world's larger calorimeter LHC (CERN, Switzerland). Therefore the light output it is not an important in comparison with the short decay time and stability parameters after large doze of gamma-rays / protons irradiation.
  • the given invention developed a production of grown by Czochralski methods large crystalline boules, having a high density, short decay time, good energy resolution and radiation resistance against irradiations by large doze of gamma-rays/protons/hadrons for application in high-energy physics.
  • An important technical task solved by the given invention is a production of large crystalline boules, having the good energy resolution and high light output of a luminescence over all volume, grown by Czochralski method for application in medicine, including of Time-Of-Flight Positron Emission Tomography (TOF PET), Depth Of Interaction or DOI PET, Single Photon Emission Computed Tomography (SPECT) and X-ray computer fluorography.
  • TOF PET Time-Of-Flight Positron Emission Tomography
  • DOI PET Depth Of Interaction or DOI PET
  • SPECT Single Photon Emission Computed Tomography
  • X-ray computer fluorography X-ray computer fluorography
  • Czochralski crystal growth process is a good cleaning procedure for different ions, for example, during growth process about 25% of cerium ions replace lutetium ions of LU2S1O5 crystal, but the other 75% cerium ions are stay in the melt.
  • the optimisation maximal concentration for each impurity ions give possibility decrease the cost production of low cost Lu 2 0 3 , and from this lutetium oxide grown LFS crystals have the same or better high scintillation parameters like crystals grown from expensive high purity LU2O3.
  • Additional technical result of this invention it is production of a scintillation cerium doped oxyorthosilicate including LFS, LSO, LYSO, LGSO, GSO crystals having reduced cost production, wherein the crystals is grown from the low price LU2O3.
  • Figure 1 is a line graph shows the absorption spectra of
  • Figure 2 shows the absorption spectra of Ce:LSO , no defects, as in the prior art according patent US 7, 166,845.
  • Figure 3 shows the absorption spectra of Ce:LYSO , no defects, as in the prior art according patent US 7, 151 ,261.
  • Figure 4 shows transmission spectra of LFS-3 crystal before and at various intervals after proton irradiation (sample length is 20 mm) in accordance with an embodiment of the present invention.
  • Figure 5 shows the Excitation spectra of
  • the excitation spectra of (5), (6), (7), (8) were measured at the emission wavelength of 460 nm at room temperature.
  • a CZ growing of low and high Ce 3+ doped LFS crystals was executed under a good thermal insulation conditions in a protective inert gas atmosphere (100% volume of nitrogen, weekly oxidising N2 and argon, 100% volume of argon), at pulling rate of 0.9 - 8 mm h " ' , rotation rate of 3 - 35 r.p.m.
  • ASPECT #1 In a first technical task of the given invention a new is a composition of advanced LFS scintillation material having emission maximum in range 400 - 450 nm and base on a silicate comprising a lutetium (Lu) and cerium (Ce) characterised in that the composition is represented by the chemical formula:
  • A is at least one element selected from the group consisting of Sc, Y, Gd, and Lu;
  • Me is at least one element selected from the group consisting of Li, Na, , Cu, Ag, Mg, Ca, Zn, Sr, Cd, B, Al, Ga, V, Cr, Mn, Fe, Co, Ni, Ti, Ge, Zr, Sn, Hf, La, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, and Lu;
  • J is at least one element selected from the group consisting of N, F, P, S, and CI;
  • w is a value between near 0 f.u. and 1 f.u.
  • x is a value between 3xl0 "4 f.u. and 0.02 f.u.
  • y is a value between 0.003 f.u. and 0.024 f.u.
  • z is a value between near 0 f.u. and 0.001 f.u.
  • j is a value between near 0 f.u. and 0.03 f.u.
  • the lower limit of w, z, j is determined the compositions in which it is not practical to measured concentration this ions by ICP-MS, GDMS analysis.
  • the upper limit z, j is designed by the maximum concentration of these elements content in scintillation material. When their content is above the indicated limit, the destruction of the structural type LU2S1O5 takes place and the formation of a few micron size inclusions of other phases, which determine very strong scattering of light and the decrease of transparency of a scintillating crystal.
  • For the upper limit is put from the fact that, at higher ions concentrations than the limit, in result this low-density crystal materials have not a perspective for application in PET scanners and high-energy physics.
  • the lower limit x is determined from experimental results, at Ce ions concentrations lower than this limit, it is not practical produce a material with high light output for application in PET scanners.
  • the upper limit x is assign by the Czochralski growth, because at Ce ions concentrations higher than this limit, it is not practical produce a large commercial crystal boules using 50% of melt.
  • the lower and upper limit y are defined by different chemical compositions of the advanced scintillation ceramic, by the compositions of melt for growth of scintillation crystals, by the investigation composition of grown crystals.
  • the lower and upper limit q are depended: (a) from concentration matrixes and impurities ions, according of the law on preservation of charge neutrality, because the charge neutrality means that the total charge of positive ions must equal the total charge of negative ions in scintillation substance; (b) an transformation of the chemical formula ( 1 ) of scintillation material into the equivalent chemical formula, having the identical mole ratios of components (Lu+Ce+A+Me)/Si and the identical percents of the oxides.
  • composition is represented by the chemical formula (Lu a A b Ce c S i d ) i - z Me z JjO q
  • A is at least one element selected from the group consisting of Sc, Y, Gd, and Lu;
  • Me is at least one element selected from the group consisting of Li, Na, , Cu, Ag, Mg, Ca, Zn, Sr, Cd, B, Al, Ga, V, Cr, Mn, Fe, Co, Ni, Ti, Ge, Zr, Sn, Hf, La, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, and Lu;
  • J is at least one element selected from the group consisting of N, F, P, S, and CI;
  • the mole ratio of (a+b+c)/d is a value between near 2.012 and 2.098;
  • d is a value between 0.997 f.u. and 0.967 f.u.
  • j is a value between near 0 f.u. and 0.03 f.u.
  • q is a value between 4.9 f.u. and 5.024 f.u.
  • z is a value between near 0 f.u. and 0.001 f.u.
  • a new is a composition of advanced LFS scintillation materials having emission maximum in range 400 - 450 nm and base on a silicate comprising a lutetium (Lu) and cerium (Ce) characterised in that the composition is represented by the chemical formula:
  • A is at least one element selected from the group consisting of Sc, Y, Gd, and Lu;
  • Me is at least one element selected from the group consisting of Li, Na, , Cu, Ag, Mg, Ca, Zn, Sr, Cd, B, Al, Ga, V, Cr, Mn, Fe, Co, Ni, Ti, Ge, Zr, Sn, Hf, La, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, and Lu;
  • J is at least one element selected from the group consisting of N, F, P, S, and CI;
  • q is a value between 4.9 f.u. and 5.0 f.u.
  • w is a value between 0 f.u. and 1 f.u.
  • x is a value between 3xl 0 "4 f.u. and 0.02 f.u.
  • y is a value between 0.001 f.u. and 0.04 f.u.
  • z is a value between 0 f.u. and 0.001 f.u.
  • j is a value between 0 f.u. and 0.03 f.u.
  • the lower limit of w, z, j is determined the compositions in which it is not practical to measured concentration this ions by ICP-MS, GDMS analysis.
  • the upper limit z, j is designed by the maximum concentration of these elements content in scintillation materials. When their content is above the indicated limit, the destruction of the structural type LU2S1O5 takes place and the formation of inclusions of other phases, which determine very strong scattering of light and the decrease of transparency of a scintillating crystal.
  • For the upper limit w is put from the fact that, at higher ions concentrations than the limit, in results this low-density crystal materials have not a perspective for application in PET scanners and high-energy physics.
  • the lower limit x is determined from experimental results, at Ce ions concentrations lower than this limit, it is not possible produce a material with high light output for application in PET scanners.
  • the upper limit x is assign by the Czochralski growth, because at Ce ions concentrations higher than this limit, it is not possible produce a large commercial crystal boules using 50% of melt.
  • the lower and upper limit y are defined by different chemical compositions of the advanced scintillation ceramic, by the compositions of melt for growth of scintillation crystals, by the investigation composition of grown crystals.
  • the lower and upper limit q are depended: (a) from concentration matrixes and impurities ions, according of the law on preservation of charge neutrality, because the charge neutrality means that the total charge of positive ions must equal the total charge of negative ions in scintillation substance; (b) An transformation of the chemical formula (2) of scintillation material into the equivalent chemical formula, having the identical mole ratios of components (Lu+Ce+A+Me)/Si and the identical percents of the oxides.
  • composition is represented by the chemical formula (LuaAbCecSid)i-zMe z JjO q
  • A is at least one element selected from the group consisting of Sc, Y, Gd, and Lu;
  • Me is at least one element selected from the group consisting of Li, Na, K, Cu, Ag, Mg, Ca, Zn, Sr, Cd, B, Al, Ga, V, Cr, Mn, Fe, Co, Ni, Ti, Ge, Zr, Sn, Hf, La, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, and Lu;
  • J is at least one element selected from the group consisting of N, F, P, S, and
  • the mole ratio of (a+b+c)/d is a value between near 1.846 and 1.996
  • d is a value between 1.01 f.u. and 1.04 f.u.
  • j is a value between near 0 f.u. and 0.03 f.u.
  • q is a value between 4.9 f.u. and 5.024 f.u.
  • z is a value between near 0 f.u. and 0.001 f.u.
  • a third task of the given invention is a creation of advanced (Lu2- W - x +2yA w Ce x Sii- y )i- z Me z J j O q scintillation materials having the silicon concentration from Sio.997 till Sio 976 and the mole ratios of components (Lu2. w -x+2y+Ce x +A w )/ Si
  • a fourth task of the given invention is a creation of advanced (Lu2- w -x- 2yAwCe x Sii +y )i-zMe z J j O scintillation materials having the total silicon concentration from Sii .001 till Sii .o4 and the mole ratios of components (Lu2- w -x-2y+Ce x +A w )/ Sii+ y ⁇ 2; the high density ⁇ 6.8 -7.4 g cm 3 , the high light output about 60-95% of Nal(Tl), the one exponential decay constant in the range 12-38 ns for different compositions, the maximum emission of light in the range 400-450 nm, the high radiation resistance against high energy protons/hadrons, no degradation in optical transmission after gamma-rays irradiation with the dose in the range approximately 5- 23 Mrad, the energy resolution for the full energy peak in the range from 6% till 10%.
  • a scintillation LFS material represented by the chemical formulas (Lu2-w- x +2yA w Ce x Sii. y )i. z Me z J j O q and (Lu2- w - x -2yA w Ce x Si
  • the said scintillation crystals have a technical result of this invention: the use as a raw materials the LU2O3 having the purity of 99.9% instead of LU2O3 with a purity of 99.995% in the known patents.
  • the low price LU2O3 allows decreasing the cost of a melting raw materials about 2 times for grown cerium-activated lutetium based oxyorthosilicate scintillation crystals.
  • the impurities Sc, Y, La, Ce, Mg, Ca, Gd, Si, S, F, CI ions have not a significant negative influence; therefore it is possible a high concentration of this ions in low
  • a large single crystal boule of cerium-activated lutetium-based oxyorthosilicate made from an off-stoichiometric melt of starting oxides, wherein the starting oxides have a purity of about 99.9% and include at least cerium oxide, lutetium oxide, and silicon oxide, and wherein at least 50% of the melt becomes part of the large crystal boule.
  • ASPECT #3 A large single crystal boule of cerium-activated lutetium-based oxyorthosilicate made from an off-stoichiometric melt of starting oxides, wherein the starting oxides have a purity of about 99.9% and include at least cerium oxide, lutetium oxide, and silicon oxide, and wherein at least 50% of the melt becomes part of the large crystal boule.
  • ASPECT #4 A scintillation material having emission maximum in the range of about 400 - 450 nm and based on cerium doped a rare-earth oxyorthosilicate including high optical quality without a light scattering particles the LFS, LSO, LYSO, LGSO , GSO crystals having defects in comparison with ideal crystal structure, and said defects change the optical transmission and absorption spectra in the range about of 200-340 nm; and the picks maximum absorptions located at wavelength ⁇ about of 250-270 nm and ⁇ 2 about of 280- 300 and ⁇ 3 about of 340-380 nm ; and said maximum absorption picks characterised in that the ratio ⁇ ( ⁇ 2 ) / ⁇ ( ⁇ 3 ) > 1.
  • ASPECT #5 A scintillation material having emission maximum in the range of about 400 - 450 nm and based on cerium doped a rare-earth oxyorthosilicate including high optical quality without a light scattering particles the LFS, LSO, LYSO, LGSO , GSO crystals having defects in comparison with ideal crystal structure, and said defects change the optical transmission and absorption spectra in the range of about 200-340 nm; and the picks maximum absorptions located at wavelength ⁇
  • a technical task solved by this invention is a production of large LFS, LSO, LYSO, LGSO , GSO crystalline boules having a high light output of a luminescence and high radiation hardness over all volume, grown by directional crystallization method, in particular, the Kyropoulas and Czochralski methods.
  • ASPECT #7 A technical task in the specific forms is a composition of scintillation crystals having intensity and an afterglow time less than the known lutetium and lutetium-yttrium oxyorthosilicate crystals have, and a light output of proposed material is comparable or higher than a lutetium and a lutetium-yttrium oxyorthosilicate has.
  • a technical task solved by this invention is a production of large crystalline boules, having a high light output of a luminescence and high radiation hardness over all volume, grown by the Kyropoulas and Czochralski methods, having additionally the sub- micron light scattering particles (inclusions).
  • the scintillation material is a crystal having additionally any light scattering particles (inclusions) with sub-micron size in the range 1 - 400 nm. For example, it is applied in design of the small animal PET scanner on base of 6 monolithic scintillation detectors. Each monolithic crystal block has size about 60x60x12 mm 3 .
  • the solid-state semiconductor photodetector includes an array of discrete sensitive areas disposed across of 60x60 mm 2 surface of LFS monolithic crystal block and each sensitive area contains an array of discrete micro-pixelated avalanche photodiodes.
  • the present monolithic crystal blocks having additionally any scattering particles (inclusions) with sub-micron size is directed to scintillation detectors capable of detecting the position or depth of gamma photon interactions occurring within a scintillator, thereby improving the resolution of ring based positron emission tomography imaging systems in:
  • ASPECT #9 A scintillation cerium doped lutetium based oxyorthosilicate including LFS, LSO, LYSO, LGSO , GSO crystals, and characterised in that the scintillation material is a crystal having additionally any light scattering particles in form inclusions with sub-micron size and said inclusions can observed in result of scattering green laser beam having approximately lasing wavelength of 530-540 nm and output power about of 1 -50 mW , and said laser beam taking place through the 6 side polished crystal sample.
  • ASPECT #10 A method of production of a scintillation cerium doped lutetium based oxyorthosilicate with reduced cost production including LFS, LSO, LYSO, LGSO, GSO crystals having additionally any scattering particles in form inclusions with sub-micron size, and the said method is the growth of crystals from the melt including Czochralski, yropulas and any other techniques, and with continual decreasing the growth rate at least approximately from about 8 mm till 1 mm per hour, at least approximately from about 5 mm till 2 mm per hour, at least approximately from about 4 mm till 2 mm per hour from top to bottom of growing crystal.
  • a fast scintillation (Lu2-w-x+2yAwCexSii-y)i- z Me z J j O q and (Lu 2 Si I +y )i- zMeJ j O q materials in form of a crystals (having additionally any scattering particles in form inclusions with sub-micron size , for example, LU2S12O7, S1O2 and LU2O3 with sub-micron size in the range 1 - 400 nm) are effective advanced materials for Gamma-ray systems designed to meet the full range of cargo inspection applications.
  • the Gamma-ray systems have an intrinsically lower radiation field when compared to equivalent X-ray systems, the Gamma-ray systems were developed for replacement of X-ray systems.
  • the Cesium- 137 gamma source for Enhanced Penetration Gamma-ray systems is used the Cobalt-60 gamma source.
  • ASPECT #11 A method of production of a scintillation cerium doped oxyorthosilicate including LFS, LSO, LYSO, LGSO, GSO crystals having reduced cost production, wherein the crystals have the impurities ions in a quantity not exceeding 10 ppmW for the Li, B, Al, Ti, V, Cr, Mn, Co, Ni, Ge, Zr, Sn, Hf ions; and less than 30 ppmW for the Na, , Cu, Ag, Zn, Sr, Cd, Fe, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb ions; and less than 100 ppmW for the Mg, Ga, La ions, and in the range 1 - 100 ppmW for the Ca, and less than 50 ppmW for N, F, CI, S , P ions.
  • the said scintillation crystals have a technical result of this invention: the use as a raw materials the LU2O3 having the purity of 99.9% instead of LU2O3 with a purity of 99.99% in the known patents.
  • the low price LU2O3 allows decreasing the cost of a melting raw materials about 2 times for grown cerium-activated lutetium based oxyorthosilicate scintillation crystals.
  • the impurities Sc, Y, La, Ce, Mg, Ca, Gd, Si, S, F, CI ions have not a significant negative influence; therefore it is possible a high concentration of this ions in low cost LU2O3.
  • GDMS Glow Discharge Mass Spectroscopy
  • ICP-MS Inductively Coupled Plasma Mass Spectrometry
  • ASPECT #13 A scintillation material having emission maximum in the range of about 400 - 450 nm and based on cerium doped a rare-earth oxyorthosilicate including LFS, LSO, LYSO, LGSO , GSO crystals having defects in comparison with ideal crystal structure, and said defects change the optical transmission and absorption spectra in the range about of 200-340 nm; and the picks maximum absorptions located at wavelength ⁇ ( about of 250-270 nm and ⁇ 2 about of 280-300 and ⁇ 3 about of 340-380 nm ; and said maximum absorption picks characterised in that the ratio ⁇ ( ⁇
  • ASPECT #14 A scintillation material having emission maximum in the range of about 400 - 450 nm and based on cerium doped a rare-earth oxyorthosilicate including LFS, LSO, LYSO, LGSO , GSO crystals having defects in comparison with ideal crystal structure, and said defects change the optical transmission and absorption spectra in the range about of 200-340 nm; and the picks maximum absorptions located at wavelength ⁇
  • Said scintillation oxyorthosilicate crystals have a technical result - mass production of large crystalline boules, having a high light output and the decay time is in the range 12 - 32 ns (TABLE 1 , Example 3, 7, 12).
  • a scintillation lutetium-based oxyorthosilicate crystal having emission maximum in range 400 - 450 nm, having the decay time in the range 12 - 32 ns for application in TOF PET and DOI PET scanners, MicroPET scanners; for detection of elementary particles and nuclei in high-energy physics; for X-ray control of quality using a non-destructive testing of solid state structure; for the inspection of trucks and cargo containers for concealed contraband, smuggled goods, and for manifest verification.
  • ASPECT #15. A scintillation material having emission maximum in the range of about 400 - 450 nm and based on cerium doped a rare-earth oxyorthosilicate including LFS, LSO, LYSO, LGSO , GSO crystals having defects in comparison with ideal crystal structure, and said defects change the optical transmission and absorption spectra in the range about of 200-340 nm; and the picks maximum absorptions located at wavelength ⁇ about of 250-270 nm and ⁇ 2 about of 280-300 and ⁇ 3 about of 340-380 nm ; and said maximum absorption picks characterised in that the ratio ⁇ ( ⁇ ) / ⁇ ( ⁇ 2) ⁇ 1 ⁇ , and said materials have the decay time in the range of 12 - 35 ns for application in TOF PET and DOI PET scanners and for detection of elementary particles and nuclei in high-energy physics.
  • time-of-flight means simply that for each annihilation event, it note precise time that each of the coincident photons is detected and calculate the difference. Since the closer photon will arrive at its detector first, the difference in arrival times helps pin down the location of the annihilation event along the line between the two detectors.
  • the TOF PET scanner has significant advantages, since conventional PET image quality degrades noticeably for large patients due to increased attenuation, which leads to the lost of true counts and increase of scatter counts. In fact, the difference in the noise-equivalent count- rate for a heavy patient (e.g. 120 kg) compared to the slim patient (e.g. 50 kg) is about a factor of six.
  • the timing resolution even about 100 ps can be achieved between two (Lu2- w -x+2yA w Ce x Sii.y)i- 2 Me z JjOq or two (Lu 2 - w -x- 2yA w Ce x Si
  • a scintillation material represented by the chemical formulas (Lu 2 .w.x +2y A w Ce x Sii- y )i_ z Me z J j O q and (Lu2-w-x-2yA w Ce x Si
  • z Me z J j O q in which the light output is in the range 35000 - 41000 ph MeV for application in medical imaging systems.
  • Neutron capture techniques as embodied in Neutron Analysis (NAs) devices, provide a powerful tool for counter terrorism and environmental demilitarization.
  • the common objective in application is the detection of explosives via their unique elemental constituents.
  • the primary explosive signature is the nitrogen concentration.
  • Hydrogen is a secondary one.
  • useful tertiary signatures exist in the full gamma-spectrum reflecting the explosive material itself and its surrounding.
  • All these signatures, or spectra features, are derived from the analysis of the gamma-ray spectra collected by LFS, annealed Ce:Ca:LSO, annealed Ce:Ca:LYSO detectors with a good energy resolution (about 7-8%), short decay time ( ⁇ 30-32 ns), high light output (up to 41000 ph/MeV), the emission maximum in the range of about 420 - 430 nm, the high effective atomic number (66), high radiation hardness, the large size about of 60-75 mm in diameter and 60-75 mm high of detecting crystal .
  • a technical result - mass production of large crystalline boules having over large boule volume a high light output of a luminescence and high radiation hardness and no degradation in optical transmission in the range 400- 450 nm after irradiation by gamma ray with the dose in the range 1 - 23 Mrad, a reproducibility of scintillation properties of monocrystals grown during mass production, is achieved by way of growing of scintillating single crystal by a method from a melt made from the charge (Lu2- w - x+ 2yA w Ce x Sii-y)i. z Me z J j O q and (Lu2- -x-2 wCe x Sii+y)i -z Me z J j O q , for example, a calcium co-doped compositions in TABLE 1.
  • a scintillation lutetium-based oxyorthosilicate crystal having emission maximum in range 400 - 450 nm, having the decay time in the range 12 - 32 ns and having hard radiation hardness, the said radiation hardness it is mean no -degradation in optical transmission in the range 400- 450 nm after irradiation by gamma ray with the dose in the range 1 - 23 Mrad, for detection of elementary particles and nuclei in high-energy physics.
  • a distribution coefficient of yttrium is 0.75 ; a distribution coefficient of calcium is 0.4; a distribution coefficient of scandium is 1 .22, a distribution coefficient of cerium is 0.365 (Example 3).
  • Ce x Lu2- w -x-z+2yYwCa z Sii.y05+ q began growing of crystal having: (a) Ce concentration is about 30%-36% than concentration in melt; (b) yttrium concentration is 75%-85% than concentration in melt for different yttrium concentrations in starting melt compositions; (c) calcium concentration is about 40% than concentration in melt; (d) silicon concentration is depended from oxygen concentration in growth atmosphere, the vaporization speed from surface of melt, the ratio (Lu+Ce+Y+Ca) / Si in the melt, therefore this parameters determinate that the silicon concentration in growing crystal may change in the range 99%- 101 % in comparison with concentration in the melt; (e) In growing crystal the lutetium concentration is in the range 100% -102% of concentration in a melt.
  • ASPECT #20 A method of production of a scintillation material having emission maximum in the range of about 400 - 450 nm and based on cerium doped a rare-earth oxyorthosilicate including LFS, LSO, LYSO, LGSO , GSO crystals having defects in comparison with ideal crystal structure, and said defects change the optical transmission and absorption spectra in the range of about 200-340 nm; and the picks maximum absorptions located at wavelength ⁇ about 250-270 nm and ⁇ 2 about 280-300 and ⁇ 3 about 340-380 nm ; and said maximum absorption picks characterised in that the ratio ⁇ ( ⁇ ) / ⁇ ( ⁇ 2 ) > 1., and said method is annealing of a samples at least in vacuum, at least in gas atmosphere about 80- 100% volume of argon + 0 - 20% volume of C0 2 at temperature about 1200-1500°C.
  • a new is that during annealing of a crystal samples at high temperature 1400-1600°C, the process of diffusion of oxygen ions and mono oxide SiO from the body of said samples into vacuum or flow gas of 100% Argon was observed.
  • Annealed Ce:LYSO crystal having defects;
  • the excitation spectra of (5), (6), (7), (8) were measured at the emission wavelength of 460 nm at room temperature.
  • Two types of excitation spectra are shown for cerium doped a rare- earth oxyorthosilicate which grown/annealed in oxygen contain atmosphere (spectra 5, 6) and after high temperature annealing said crystal samples (spectra 7, 8) into vacuum or flow gas of 100% Argon.
  • Fig.5 displays the excitation spectra of (7) annealed Ce:LSO and (8) annealed Ce:LYSO crystals, both having defects in comparison with ideal crystal structure: for example, the vacancy/ interstitial for Lu ions, or the interstitial/vacancy for silicon ions, or the oxygen vacancy.
  • the excitation spectra (7), (8) have not a maximum about 376 nm and it is mean, that these samples have not a long time emission components for gamma excitation.
  • the decomposition of scintillation cerium doped lutetium- based oxyorthosilicates exists in high vacuum at 1750°C, there are vaporization of oxygen and mono oxide SiO.
  • the surfaces of sample decomposed into LU2O3 and the volume have dark colour in results of loss of oxygen. Therefore the optimal method is annealing of a samples at least in vacuum, at least in gas atmosphere about 80-100%) volume of argon + 0 - 20% volume of C0 2 at temperature about 1200- 1500°C.
  • the specified method includes the following stages: (1 ) The growth of LFS, LSO, LYSO, LGSO single crystals by Czochralcki (CZ) or Kyropoulas methods; (2) The cutting of grown boule at samples having approximately cross-section from 3x3 mm till 25x25 mm and the thickness from 2 mm till 25 mm; (3) Annealing of a crystal samples in vacuum or gas atmosphere 80-100% volume of argon + 0 - 20% volume of CO 2 at temperature about 1400-1500°C, (4) At the final stage from this annealed samples it was produced, for example, the polished pixels for application in TOF PET and DOI PET scanners or active scintillated plates with size up to 25x25x5 mm 3 of a "Shashlik"-type readout for the High-Luminosity Large Hardron Collider (HL-LHC).
  • a technical result in the specific forms of implementation is achieved by way of using a scintillation LFS, LSO, LYSO, LGSO materials in the form of a high temperature annealed single crystal, having a light output in the range 35000 - 41000 ph/MeV.
  • TABLE 1 shows the results of testing of the synthesised scintillating materials.
  • the Concentration of doping ions (ppmw), Decay time (ns), Light yield (relative units), Degradation transmission at 420 nm due to ⁇ -rays irradiation are compared for different compounds.
  • the values of light yield are presented in units relative to a light yield of "the reference" Ceo.0013 Lu2.02Sco.003Sio.99O5.012 sample.
  • Hf, Ga ions Hf, Ga ions; ⁇ 10 ppmW for a Na, K, Zn, Sr, La, Pr,
  • the oxide chemicals (LU2O3, Ce0 2 , S1O2) with purity of 99.99% were used for the growing by Czochralski method (CZ) of crystal boule. Content of cerium in top of boule is need about 3x10 "4 f. units.
  • a CZ growing of crystal was executed from an iridium crucible of the 80 mm in diameter under a good thermal insulation conditions in a protective inert gas atmosphere ( 100% volume of nitrogen), at pulling rate of 1.2 mm h ⁇ ' , rotation rate of 10 r.p.m. In these growth conditions the crystals approximately 40 mm in diameter and up to 80 mm length was grown.
  • the oxide chemicals (LU2O3, Ce0 2 , Si0 2 ) with purity of 99.99% were used for the growing by Czochralski method (CZ) of crystal boule.
  • a CZ growing of crystal was executed from iridium crucible in a protective nitrogen gas atmosphere.
  • the polished samples from top and bottom part of boule were used for measurement parameters and chemical compositions (TABLE 1).
  • Concentration of impurities from raw materials are: 1 1 ppmw - CI; 5 ppmw - P; 3 ppmW - Ca; 1.5 ppm W - Yb; ⁇ 2 ppmW for a Li, Na, K, Al; ⁇ 0.5 ppmW for a Li, Na, , Cu, Mg, Zn, Sr, B, Ga, Ti, Zr, Sn, Hf, La, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm ions.
  • the degradation in optical transmission at 420 nm of crystal sample from top of boule is 7%/cm after irradiation by 5 * 10 6 rad ⁇ -rays doses.
  • the degradation in optical transmission at 420 nm of crystal sample from bottom of boule is 4%/cm after irradiation by 5* 10 6 rad ⁇ -rays doses.
  • a CZ growing of crystal was executed from a iridium crucible in a protective inert gas atmosphere (100% volume of argon).
  • a protective inert gas atmosphere (100% volume of argon).
  • the LFS crystal boule has continuous shift of the chemical compositions from top to bottom.
  • a distribution coefficient of yttrium is 0.75 ; a distribution coefficient of calcium is 0.4; a distribution coefficient of scandium is 1.22, a distribution coefficient of cerium is 0.365.
  • the said samples were annealed in a vacuum at temperature about 1400°C during 6 hours. At the final stage from this annealed samples was produced polished samples with size 4x4x22 mm.
  • the polished sample was used for measurement of parameters and chemical composition (TABLE 1 ).
  • Concentration of impurities from raw materials are: ⁇ 5 ppmW for a Li, B, Al, Ti, Zr, Sn, Hf, Ga ions; ⁇ 10 ppmW for a Na, K, Zn, Sr, La, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm ions; ⁇ 30 ppmW for a Mg, Yb ions.
  • a CZ growing of crystal was executed from a large iridium crucible in a protective inert gas atmosphere. The crystals approximately 90 mm in diameter and 200 mm length was grown. The polished samples were used for measurement parameters and chemical compositions (TABLE 1 ).
  • Concentration of impurities from raw materials are: 10 ppmw -Yb; 8 ppmw - Na, CI; ⁇ 5 ppmW for a Li, Na, Al, K, Cu, Mg, Zn, Sr, B, Ga, Ti, Zr, Sn, Hf, La, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm ions.
  • the degradation in optical transmission at 420 nm of crystal sample there are not after irradiation up to 23* 10 6 rad ⁇ -rays doses.
  • a CZ growing of crystal was executed from large iridium crucible in a protective nitrogen gas atmosphere.
  • the crystals approximately 95 mm in diameter and up to 200 mm length was grown.
  • the polished samples produced from top part of boule was used for measurement parameters and chemical composition (TABLE 1).
  • Concentration of impurities from raw materials are: 1 1 ppmw -Yb ; 9.5 ppmw - CI ; 3 ppmw - Ca; ⁇ 2 ppmw Al, Mg, P, S; ⁇ 1 ppmW for a Na, K, Cu, Zn, Sr, B, Ga, Ti, Zr, Sn, Hf, La, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm ions.
  • the degradation in optical transmission at 420 nm of crystal sample from bottom of boule are 4.8%/cm after irradiation by 5 * 1 0 6 rad ⁇ -rays doses.
  • Concentration of impurities in the Lu 2 0 3 are: 250 ppmw -Gd; 100 ppmw -Tb; ⁇ 35 ppmW for a Dy, Ho, Er, Tm; 100 ppmw - Ca, F; 120 ppmw - Si, CI; 50 ppmw - Fe.
  • Produced from bottom part of boule the polished samples were used for measurement of parameters (TABLE 1 ).
  • Concentration of impurities from raw materials are: 8 ppmw -Yb, Al, CI; 6 ppmw - S; ⁇ 5 ppmW for a Na, K, Cu, Mg, Zn, Sr, B, Ga, Ti, Zr, Sn, Hf, La, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm ions.
  • the degradation in optical transmission at 420 nm of annealed in a vacuum the crystal samples are 0.8%/cm after irradiation by 23 * 10 6 rad ⁇ -rays doses.
  • Concentration of impurities in melt from raw materials are: 35 ppmw - Ca; 9 ppmw -Yb; ⁇ 0.5 ppmW for a Na, , Cu, Mg, Zn, Sr, B, Ga, Ti, Zr, Sn, Hf, La, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm ions.
  • This example is an experimental support for a creation of advanced (Lu2- w -x- 2yAwCe x Sii + y)i- 2 Me z J j O scintillation materials having the total silicon concentration from Sii.001 till Sii .04 and the mole ratios of components (Lu 2 -w-x-2y+Ce x +A w )/ Sii+ y ⁇ 2; the high density ⁇ 6.8 -7.4 g/cm 3 ; the high light output about 60-95% of Nal(Tl); the one exponential decay constant in the range 12-35 ns; the maximum emission of light in the range 400-450 nm; and the high radiation resistance against gamma-rays irradiation.
  • a CZ growing of crystal was executed from an iridium crucible in a protective inert gas atmosphere (100% volume of argon).
  • Concentration of impurities from raw materials are: 5 ppmW for a Ca, Yb,. ⁇ 0.5 ppmW for a Li, Na, K, Cu, Mg, Zn, Sr, B, Ga, Ti, Zr, Sn, Hf, La, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm ions;
  • This example is an experimental support for a task of the given invention: a creation of cerium doped a rare-earth oxyorthosilicate including annealed in a vacuum of LFS, LSO, LYSO, LGSO crystals having defects in comparison with ideal crystal structure, and said defects change the optical transmission and absorption spectra in the range about of 200-340 nm; and said crystal have the high density ⁇ 6.8 -7.4 g/cm 3 ; the high light output about 60-95% of Nal(Tl); the one exponential decay constant in the range 12-35 ns; the maximum emission of light in the range 400-450 nm; no degradation in optical transmission after gamma-rays irradiation with the dose up to 23 Mrad.
  • Optical transmission spectra across a 20 mm thickness were measured with a spectrophotometer before and at various intervals after proton irradiation. Due to induced radioactivity of LFS crystals first measurements of optical transmission of crystals samples were made in 30 days after proton irradiation.
  • a crystal having composition Ce0.0014Lu 1.977Y0.037 Cao.001 Sio.992O5.007 and a crystal grown from melt Ceo.012Lu1.92sYo. 12Sio.97O5.03 was used for investigation proton induced damage.
  • a CZ grown crystal from Ceo 012Lu 1.928Y0 12Sio.97O5.03 melt composition having the concentration of impurities in melt from raw materials: 27 ppmw -Yb; 35 ppmw - Ca; ⁇ 30 ppmW for a Li, B, Al, Ti, V, Cr, Mn, Co, Ni, Ge, Zr, Sn, Hf, Na, K, Cu, Ag, Zn, Sr, Cd, Fe, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm; ⁇ 50 ppmW for the N, F, P, CI, S, Mg, Ga, La ions was investigated.
  • the said crystal has high radiation hardness and no degradation reduction in optical transmission in the range 400- 450 nm after irradiation by high-energy protons of 155 MeV/c protons with fluency 4x l 0 12 cm "2 .
  • Concentration of impurities from raw materials are: 10 ppmw -Yb; 8 ppmw - Na, CI; ⁇ 5 ppmW for a Li, Na, Al, K, Cu, Mg, Zn, Sr, B, Ga, Ti, Zr, Sn, Hf, La, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm ions.
  • EXAMPLE 11 The Light Yield (ph/MeV) and energy resolution (%) of a fast scintillation (Lu 2 . w - x+2yA w Ce x Sii -y )i -z Me z J j O q and (Lu2.w-x-2yAwCe x Sii+y)i- z Me z J j Oq materials in form of a crystal are important for PET scanners. Prior to measurement of the energy resolution, the samples were stored in the dark for at least 24 h to eliminate the thermoluminescence emission that is stored upon exposure to white light.
  • Light collection was carried out by placing the crystal directly onto a Hamamatsu R4125Q photomultiplier tube (with quartz window); a fast amplifier ORTEC 579 and a charge-sensitive height converter ADC LeCroy 2249W were used.
  • the crystal samples were covered with a Teflon tape and an Al foil to enhance the light collection efficiency.
  • a Cs 137 source was located 15 mm from the crystal surface.
  • the natural background spectrum from the Lu 176 beta decay was minimal due to the small samples size and was not subtracted.
  • the position of the full energy peak from l 37 Cs source was compared with that of the single photoelectron peak.
  • the sizes samples were 4x4x22 mm (6 sides polished) in Positron Emission Tomography (PET) scanners for the whole-body imaging during diagnostic at early stage cancer of a patient in hospitals.
  • PET Positron Emission Tomography
  • the sizes samples are 3x3x10 mm3 or 3x3x15 mm3 mm (6 sides polished).
  • a crystal having composition Ce0.0014Lu 1.977Y0.037 Cao.001 Sio.992O5.007 was used for production pixels with size 4x4x22 mm 3 (6 side polished), 3x3x 10 mm 3 (6 side polished) and the 6 side polished plates with cross section 8x8 mm 2 and thickness 1 mm.
  • Concentration of impurities from raw materials are: 10 ppmw -Yb; 8 ppmw - Na, CI; ⁇ 5 ppmW for a Li, Na, Al, K, Cu, Mg, Zn, Sr, B, Ga, Ti, Zr, Sn, Hf, La, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm ions.
  • the crystal 4x4x22 mm 3 pixel covered with Teflon reflector and additionally with Al foil reflector from 5 surfaces and the open 4x4 mm 2 surface was placed directly on the Hamamatsu R4125Q photomultiplier.
  • EXAMPLE 12 A method of production of a scintillation cerium doped lutetium-based oxyorthosilicate including LFS, LSO, LYSO, LGSO crystals having the decay time in the range 12 - 32 ns, and said method is annealing of a crystal samples in vacuum or 100% Argon atmosphere at temperature about 1400-1600°C during time about 12- 72 hours.
  • the LYSO crystal was grown by Czochralski method. After cutting of grown LYSO boule at samples, a part of said samples were annealed in a vacuum at temperature about 1450°C during 12 hours. At the final stage from this annealed samples was produced polished samples. The annealed in a vacuum LYSO samples demonstrated decay time in the range 30-32 ns, in comparison with decay time in the range 41 -44 ns of LYSO samples after growth in atmosphere of 99.7% volume of nitrogen with 0.3 % volume of oxygen.
  • the oxide chemicals (LU2O3, Ce0 2 , Gd 2 0 3 , Si0 2 ) were used for the growing by Czochralski method of cerium doped lutetium-gadolinium oxyorthosilicate Ce x Lu2-x- y Gd y Si0 5 (LGSO).
  • the grown LGSO crystal had a high optical quality and did not comprise the fine scattering inclusions.
  • a method of production of a scintillation cerium doped lutetium-based oxyorthosilicate including LFS, LSO, LYSO, LGSO crystals having hard radiation hardness the said radiation hardness it is mean no-degradation in optical transmission in the range 400- 450 nm after irradiation by gamma ray with the dose in the range 5- 23 Mrad, and method is annealing of a said crystal samples in vacuum or 100% Argon atmosphere at temperature about 1400°C.
  • the oxide chemicals (Lu 2 0 3 , Ce0 2 , Si0 2 ) with purity of 99.995% were used for the growing by Czochralski method of cerium doped lutetium oxyorthosilicate Ce2 X Lu2(i- ) Si0 5 (LSO).
  • Crystallization was executed in a protective nitrogen atmosphere (99.8% volume of nitrogen with 0.2% volume of oxygen).
  • the grown LSO crystal had a high optical quality and did not comprise the fine scattering inclusions.

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Abstract

La présente invention concerne une création de matériaux à scintillement avancé présentant un maximum d'émission dans la plage allant d'environ 400 à 450 nm et faisant appel à un orthosilicate de terre rare dopé au cérium comprenant des cristaux de LFS, LSO, LYSO, LGSO, GSO présentant des défauts en comparaison avec une structure cristalline idéale et lesdits défauts changent les spectres d'absorption et de transmission optique dans la plage allant d'environ 200 à 340 nm. Les pics d'absorption maximale caractérisés en ce que le rapport de Α(λ1 = 250-270 nm) / Α(λ3 = 280-300 nm) > 1, Α(λ2 = 280-300) / Α(λ3 = 340-380) > 1, Α(λ1 = 250-270) / Α(λ2 = 280-300 nm) > 1. L'invention est utile à la détection de particules élémentaires et de noyaux en physique des hautes énergies, l'industrie nucléaire ; la médecine, la tomographie par émission de positons (scanners DOI PET et TOF PET) et la tomographie monophotonique d'émission (SPECT), la tomographie par émission de positons couplée à l'imagerie par résonance magnétique (PET/RM) ; la radiophotographie informatique par rayons X ; l'analyse non destructive de structure à l'état solide, comprenant les systèmes de sécurité d'aéroport, les systèmes à rayons Gamma d'inspection des camions et des conteneurs de fret.
PCT/IB2015/000949 2014-06-03 2015-06-15 Matériaux d'orthosilicate de terre rare dopé au cérium présentant des défauts destinés à l'amélioration ou aux paramètres de scintillement WO2015185988A1 (fr)

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CN109884684A (zh) * 2019-01-10 2019-06-14 中国科学院高能物理研究所 一种用于pet闪烁晶体性能测试的电子学数据处理方法及系统
CN112051248A (zh) * 2020-08-26 2020-12-08 西北核技术研究所 基于激光激发的闪烁材料光产额非线性测量方法及系统
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US10907096B2 (en) 2010-11-16 2021-02-02 Saint-Gobain Cristaux & Detecteurs Scintillation compound including a rare earth element and a process of forming the same
CN112522787A (zh) * 2020-11-16 2021-03-19 中国科学院上海硅酸盐研究所 一种硅格位掺杂竞争发光中心的稀土正硅酸盐闪烁材料及其制备方法和应用
CN114059160A (zh) * 2020-08-06 2022-02-18 中国科学院上海硅酸盐研究所 一种制备稀土离子掺杂氟铝钙锂石闪烁晶体用多晶烧结料及其单晶的方法和应用

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US11927707B2 (en) 2004-08-09 2024-03-12 Luxium Solutions, Llc Dense high-speed scintillator material of low afterglow
US10890670B2 (en) 2004-08-09 2021-01-12 Saint-Gobain Cristaux Et Detecteurs Dense high-speed scintillator material of low afterglow
US11927708B2 (en) 2004-08-09 2024-03-12 Luxium Solutions, Llc Dense high-speed scintillator material of low afterglow
US10907096B2 (en) 2010-11-16 2021-02-02 Saint-Gobain Cristaux & Detecteurs Scintillation compound including a rare earth element and a process of forming the same
US11926777B2 (en) 2010-11-16 2024-03-12 Luxium Solutions, Llc Scintillation compound including a rare earth element and a process of forming the same
US10901099B2 (en) 2015-02-26 2021-01-26 Saint-Gobain Cristaux & Detecteurs Scintillation crystal including a co-doped rare earth silicate, a radiation detection apparatus including the scintillation crystal, and a process of forming the same
US11921243B2 (en) 2015-02-26 2024-03-05 Luxium Solutions, Llc Scintillation crystal including a co-doped rare earth silicate, a radiation detection apparatus including the scintillation crystal, and a process of forming the same
CN105986320A (zh) * 2016-02-16 2016-10-05 安徽火天晶体科技有限公司 Sc,Ce共掺杂的硅酸镥、硅酸钇镥晶体及其熔体法生长方法
CN109884684A (zh) * 2019-01-10 2019-06-14 中国科学院高能物理研究所 一种用于pet闪烁晶体性能测试的电子学数据处理方法及系统
CN109884684B (zh) * 2019-01-10 2020-09-15 中国科学院高能物理研究所 一种用于pet闪烁晶体性能测试的电子学数据处理方法及系统
CN114059160A (zh) * 2020-08-06 2022-02-18 中国科学院上海硅酸盐研究所 一种制备稀土离子掺杂氟铝钙锂石闪烁晶体用多晶烧结料及其单晶的方法和应用
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CN112051248B (zh) * 2020-08-26 2023-12-15 西北核技术研究所 基于激光激发的闪烁材料光产额非线性测量方法
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