Process for growing lanthanum chloride crystal by falling method of antivacuum crucible

A crucible descending method and lanthanum chloride technology are applied in chemical instruments and methods, single crystal growth, single crystal growth and other directions, which can solve the problems of growth failure, crystal devitrification, scintillation performance, decline, etc., and achieve low cost and easy operation. Effect

Inactive Publication Date: 2008-04-30
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, due to the crystallization water in the raw material and the oxidation and volatility of water at high temperature, it is easy to cause the quartz crucible to burst during the crystal growth process, resulting in growth failure.
In addition, water or other oxygen-containing impurities in the raw material will also interact with LaCl 3 reaction to form lanthanum oxychloride (LaOCl), which devitrifies the crystal and reduces scintillation performance

Method used

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  • Process for growing lanthanum chloride crystal by falling method of antivacuum crucible
  • Process for growing lanthanum chloride crystal by falling method of antivacuum crucible

Examples

Experimental program
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Embodiment 1

[0018] Grow LaCl 3 The specific process steps of the crystal are:

[0019] (1) With high-purity LaCl 3 ·nH 2 O (n = 3 ~ 7) as raw material, in an inert flow atmosphere (N 2 or Ar gas) or suppressed flow atmosphere (HCl), according to the differential thermal analysis results of raw materials, first remove the adsorbed water at a temperature of 120 ° C, and then increase the temperature at 150 ° C, 180 ° C, 220 ° C and 250 ° C respectively At a temperature of ℃, the water of crystallization is removed, dried, and dried in stages;

[0020] (2) select carbon tetrachloride to be deoxidizer, mix with the powder material after step (1) process, and add-on is 800ppm;

[0021] (3) LaCl of φ25×200m 3 The grain crystal is placed in the bottom of the crucible made of rectangular columnar iridium, and then the raw materials of the above step (2) are put in, and the crucible is sealed; the wall thickness of the crucible is 0.20mm;

[0022] (4) Four straight silicon-molybdenum rods ar...

Embodiment 2

[0027] (1) High-purity LaCl 3 ·nH 2 O (n = 3 ~ 7) as raw material, in an inert flow atmosphere (N 2 or Ar gas) or suppressed flow atmosphere (HCl), according to the differential thermal analysis results of raw materials, first remove the adsorbed water at a temperature of 120 ° C, and then increase the temperature at 150 ° C, 180 ° C, 220 ° C and 250 ° C respectively At a temperature of ℃, the water of crystallization is removed, dried, and dried in stages;

[0028] (2) High-purity cerium chloride (CeCl) used as a luminescent activator 3 ) also needs to be dried in an oven at a temperature not lower than 120°C for 4-6 hours before being incorporated into the main raw material. Then follow the equivalent LaCl 3 The molar ratio is 10% and the ingredients are fully mixed evenly;

[0029](3) Platinum material is selected and processed into a cylindrical crucible of φ25×200mm, with a wall thickness of 0.12mm, sealed with argon gas, and tested for airtight leaks to ensure that ...

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Abstract

The invention relates to the method used non vacuum falling crucible method to growth lanthanum chloride crystal. Its features are that the raw material is high pure LaCl3 containing crystal water; no water lanthanum chloride material is dehydrated under inert atmosphere at under 150 centigrade degree and preserved heat for 10-20h. Deoxidizer is one of activated carbon, crystalline flour, lead fluoride or carbon tetrachloride. Static double warm areas furnace structure is adopted. Micro motor drive speed adjusting gear is used to make crucible descend with adjustable constant speed. It has simple operation, low cost, and good performance, and is fit for large-scale production. The formed Ce: LaCl3 crystal can be applied to nuclear medicine imaging SPECT, nuclear radiation detecting, safety inspection, and geologic prospecting.

Description

technical field [0001] The invention relates to a method for growing lanthanum chloride crystals by a non-vacuum crucible descending method, more precisely to pure lanthanum chloride (LaCl 3 ) and cerium-doped lanthanum chloride (LaCl 3 :Ce) crystal preparation method, in particular to a method of growing high-quality lanthanum chloride and cerium-doped lanthanum chloride crystals with a platinum crucible descending method. The invention belongs to the technical field of crystal growth. technical background [0002] LaCl 3 : Ce is a new type of scintillation crystal discovered by Dutch scientist O.Guillot in 1999. It belongs to the hexagonal crystal system and the space group is P6. 3 / m, the density is 3.86g / cm 3 , with a melting point of 859°C [Guillot-Noel O.De Haas J.T.M.Dorenbos P.et al., Optical and scintillation properties of cerium-doped LaCl 3 , LuBr 3 and LuCl 3 . J. Lumin. 1999, 85: 21-35]. At that time, they used the Bridgman method in which the furnace ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C30B11/00C30B29/12
Inventor 任国浩裴钰陈晓峰李中波陆晟沈勇
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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