Scintillation substances (variants)

A scintillator and melt technology, applied in crystal growth, polycrystalline material growth, luminescent materials, etc., can solve the problems of large loss of crystalline materials, low efficiency detection of gamma radiation, etc.

Active Publication Date: 2008-11-26
ZELKTECH MEDICAL SYST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Low Density Scintillator of 3.8 g / cm3 Causes Inefficient Detection of Gamma Radiation
Another general technical disadvantage of lutetium orthosilicate-based scintillation crystals is due to the cutting of large (up to 60 mm in diameter) blocks into 1 mm thick pieces (these pieces are then cut into rods to generate an X-ray tomographic The large loss of crystalline material caused by cracking in the process of tens of thousands of 1×1×10 cubic millimeter elements required by the camera

Method used

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  • Scintillation substances (variants)
  • Scintillation substances (variants)
  • Scintillation substances (variants)

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0169] Example 1. "Reference" Ce:Lu with known Lu / Si=2 2 SiO 5 The growth of crystals, and the growth of crystals with a chemical formula unit ratio of (Lu+Ce) / Si=2.061 (y=0.015), which is outside the composition range of modification 1 of the present invention.

[0170] Due to the large data distribution between the crystal parameters published in different publications, the commercially available Ce:Lu 2 SiO 5 Crystal parameters can be accepted as the most reliable data. LSO crystals with a concentration of cerium ions equal to 0.12at% (or about 0.002f. units) show higher light output, the chemical formula of the reference crystal is Ce 0.002 Lu 1.998 SiO 5 . Considering that the segregation coefficient of cerium ions between the melt and the growing crystal is equal to about k=0.2, it is necessary to add a raw material having a cerium concentration of about 0.6 at% (or chemical formula unit: 0.012f. unit) in the crucible. Lu should be calculated considerin...

Embodiment 2

[0175] Example 2. Verification of the present invention in a specific embodiment—a scintillator manufacturing method. In order to grow large single crystals by the Kyropoulos method according to variants #1, #2, #3 and #4, a crystal with 51.9% (Ce 2 o 3 +Lu 2 o 3 +A 2 o 3 +Li 2 O) / 48.1%SiO 2 Optimal scintillator for the feed composition characterized by the oxide molar ratio. At this oxide ratio, the composition of the melt and crystals is given by the formula Ce x Li q+p Lu 2.076-p-x-z A z Si 0.962 o 5.038-p is characterized, wherein A is at least one element selected from Gd, Sc, Y, La, Eu, Tb, and x is 1×10 -4 The value between f. unit and 0.02f. unit, z is the value not exceeding 0.05f. unit, and q+p is the value not exceeding 0.025f. unit.

[0176] Growth of crystals with a diameter of 78 mm was performed from an iridium crucible with an inner diameter of 96 mm and a height of about 112 mm using a computer-controlled device equipped with a ...

Embodiment 3

[0182] Example 3. Method for the manufacture of scintillators in the form of scintillation ceramics based on lanthanum and lutetium oxidized orthosilicates, with the difference that Lu, La, Ce and SiCl are used 4 The aqueous chloride mixture mixture of liquid is used as feedstock for preparation (this feedstock has 51.9% (Lu 2 o 3 +La 2 o 3 +Ce 2 o 3 ) / 48.1%SiO 2 The oxide molar ratio is characteristic of the composition) of the raw materials. Aqueous ammonium carbonate solution was added to the mixture. The mixture was then filtered, drained and dried. After calcination at 1400°C, the resulting oxide mixture was stirred with added solvents and low-melting impurities, which facilitate the diffusion of atoms across grain boundaries during the final high-temperature anneal. Many compounds can be used as low melting point impurities and they do not affect the Ce 3+ emission of ions. Our studies show that small additions of Li, Na, K, Cs, Be, B, F, Al, S, Cl, ...

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Abstract

The inventions relate to the scintillation substances and they may be utilized in nuclear physics, medecine and oil industry for recording and measurements of X-ray, gamma -ray and alpha- ray, nondestructive testing of solid states structure, three-dimensional positron-emission tomography and X-ray computer tomography and fluorography. The scintillating substances based on a silicate comprising a lutetium (Lu) and cerium (Ce) characterised in that the compositions of substances are represented by the chemical formulae CexLu2+2y-xSi1-yO5+y CexLiq+pLu2-p+2y-x-zAzSi1-yO5+y-p CexLiq+pLu9,33-x-p-z 0,67AzSi6O26-p where A is at least one element selected from the group consisting of Gd, Sc, Y, La, Eu, Tb, x ia a value between 1x10<-4>f. units and 0.02 f. units., y is a value between 0.024 f. units and 0.09 f. units, z is a value does not exceeding 0.05 f. units, q is a value does not exceeding 0.2 f. units, p is a value does not exceeding 0.05 f. units, CexLi1+q+pLu9-x-p-zAzSi6O26-p z is a value does not exceeding 8.9 f. units. The achievable technical result is the scintillating substance having a high density, a high light yield, a low afterglow, and a low percentage loss during fabrication of scintillating elements for three-dimensional tomograph (PET).

Description

technical field [0001] The invention is applicable to scintillation materials and can be used in nuclear physics, medicine and petroleum industry for recording and measuring of X-rays, gamma-rays and alpha-rays; non-destructive testing of solid-state structures; three-dimensional positron-electron computed tomography (PET) and X-ray computed fluorography. The relevance of the present invention is that in fluoroscopy, X-ray computed tomography and PET, the addition of new / improved scintillators significantly improves image quality and / or reduces measurement times. (“Inorganic scintillators in medical imaging detectors” Carel W.E. van Eijk, Nuclear Instruments and Methods in Physics Research A 509(2003) 17-25). Background technique [0002] Known scintillation substances are oxyorthosilicate lutetium powders doped with cerium Lu 1.98 Ce 0.02 SiO 5 (A.G.Gomes, A.Bril "Preparation and Cathodoluminescence of Ce 3+ activated yttrium silicates and some isostructural compounds...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C30B29/34C30B11/00C30B15/00C30B15/34C30B17/00C30B28/06C30B28/10C04B35/16C09K11/08C09K11/77
CPCC30B29/34C30B11/00C09K11/7706C04B2235/3227C04B2235/3203C04B2235/3229C30B15/00C04B2235/3224C04B2235/3225C04B35/16C04B2235/3208C09K11/77742
Inventor A·I·扎古苗内Y·D·扎瓦尔采夫S·A·库托沃伊
Owner ZELKTECH MEDICAL SYST
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