Anion and cation co-doped PbWO4 crystal and its growth method

An anion and cation, growth method technology, applied in high light yield anion and cation double-doped lead tungstate crystals, high light yield lead tungstate crystals and their growth fields, can solve the problems of slow luminescence, achieve high yield, reduce The effect of cracking and growth temperature field stabilization

Inactive Publication Date: 2007-03-21
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a high-light-yield lead tungstate crystal doped simultaneously with anions and cations and a growth method thereof, aiming at fast-decaying and high-light-yield PWO crystals, aiming at low light yield and existing PWO crystals Doping introduces problems such as the slow component of luminescence and the volatilization of raw materials. The present invention uses PbF 2 or BaF 2 and Y 2 o 3 As a dopant, achieve the purpose of double doping of anion and cation; take corresponding technical measures to control the volatilization of raw materials and dopants; use the improved crucible drop method to grow the above PWO crystal

Method used

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  • Anion and cation co-doped PbWO4 crystal and its growth method
  • Anion and cation co-doped PbWO4 crystal and its growth method
  • Anion and cation co-doped PbWO4 crystal and its growth method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] 1. The purity is both 99.99% high-purity PbO and WO 3 The powder is precisely prepared according to the stoichiometric ratio, and is melted in a platinum crucible to make a highly dense PWO polycrystalline ingot;

[0030] 2. A φ25×400mm crucible is made of a single-layer platinum sheet with a thickness of 0.12mm;

[0031] 3. A single crystal with orientation and a size of φ24.5×65mm is used as the seed crystal;

[0032] 4. With PbF 2 and Y 2 o 3 As a dopant, 700ppm (at%) PbF was added after loading the raw material into a platinum crucible 2 and 300ppm(at%) of Y 2 o 3Dopant, then install the seed crystal and close the crucible;

[0033] 5. Put the platinum crucible with raw material and seed crystal into the downcomer;

[0034] 6. Raise the temperature of the furnace to 1150°C at a rate of 80°C / hour, keep it warm for 4 hours, and then gradually raise the downcomer. After all the raw materials and the top of the seed crystal are melted, keep it warm for 2 hours,...

Embodiment 2

[0038] 1. High-purity PbO and WO after roasting 3 Precisely formulated according to stoichiometry, and made into high-density PWO polycrystalline ingot after melting;

[0039] 2. Use a square platinum crucible with a thickness of 0.14mm and a size of 25×25×450mm;

[0040] 3. A single crystal with an orientation of and a size of 24.5×24.5×65 mm is used as a seed crystal.

[0041] 4. With BaF 2 and Y 2 o 3 As a dopant, add 900ppm (at%) BaF after loading the polycrystalline ingot into a platinum crucible 2 and 100ppm(at%) of Y 2 o 3 Dopant, then install the seed crystal and close the crucible.

[0042] 5. Control the temperature of the furnace to 1200°C, lower the downcomer at a rate of 0.4mm / hour, and the growth temperature gradient is 20-30°C / cm;

[0043] 6. The grown crystals can be processed directly without post-treatment.

[0044] 7. In this example, 6 crystals were grown in one furnace.

[0045] 8. Other conditions are the same as example 1.

Embodiment 3

[0047] In this example, the temperature of the furnace is controlled at 1250° C., the crucibles are 25×25×475 mm and φ25×475 mm, and 28 crystals are grown in one furnace, and other conditions are the same as in Example 1 or 2. The light yield of the grown double-doped crystals is compared with that of pure PWO crystals are listed in Table 1.

[0048]

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Abstract

The present invention relates to improved crucible descending process to grow anion and cation double doped flash lead tungstate crystal with high light efficiency and fast attenuation, and belongs to the field of crystal growing technology. The present invention solves the problem of dopant volatilization and produces anion and cation double doped PWO crystal with light efficiency up to 7.3 % of that of BGO crystal. The present invention adopts PbF2 or BaFe and Y2O3 as dopant and has doping amount of 600-1000 ppm and 100-300 ppm separately. By means of using platinum crucible, sealing crucible, controlling the volatilization of material and dopant and adopting crucible with shape and size varying with the grown crystal, the present invention can grow 2, 6 or 28 pieces of lead tungstate crystal simultaneously and is suitable for mass production.

Description

technical field [0001] The present invention relates to a high-light-yield lead tungstate crystal doped simultaneously with anions and cations and a growth method thereof. More precisely, it is a double-doped anion-cation with high light-yield double-doped anion and cation, which utilizes an improved crucible drop method to grow quickly and attenuate. Method for lead tungstate crystals. It belongs to the field of crystal growth. Background technique [0002] In the early 1990s, with the rise of high-energy physics research projects exploring elementary particles, lead tungstate PbWO 4 (PWO for short) crystals have been widely used in this field due to their high density, high absorption coefficient, short radiation length, high radiation hardness and fast luminescence decay. However, the disadvantage of low light yield (the number of photoelectrons produced per MeV) of PWO crystals seriously limits its application in high-energy fields. How to improve the light yield of PW...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C30B29/32C30B11/00
Inventor 严东生殷之文廖晶莹沈炳孚童乃志邵培发袁晖谢建军叶崇志周乐萍李培俊吴泓澍杨培志倪海洪刘光煜
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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