Process for preparing lead tungstate-doped crystal

A lead tungstate, crystal technology, applied in the direction of crystal growth, chemical instruments and methods, single crystal growth, etc., can solve the problems of uneven distribution, decreased diffusion, impossible to achieve, etc.

Inactive Publication Date: 2010-02-03
JIAXING UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0002] The existing technology is relatively successful in growing lead tungstate and some oxides with relatively high melting point doping modified lead tungstate crystals, but it encounters difficulties in growing dopant doping with low melting point and strong volatility, because in these When growing crystals in the device, it is usually necessary to reserve a part of the upper part of the crystal raw material in the crucible to contain the oxygen needed for crystal growth. The temperature distribution in the crystal growth furnace is as follows: figure 1 As shown, the upper temperature is higher, the crystal growth raw material and the dopant are in a molten state, and doped with a non-volatile dopant such as La 2 o 3 The effect of the reserved space on crystal growth is not very obvious, but in the growth of low melting point and high volatility such as PbF 2 When doping substances, the severe volatilization of doping substances will make doping almost impossible
[0003] In order to solve this problem, Chinese application number 200310109408.4 "Preparation method of fluoride ion-doped lead tungstate scintillation crystal" discloses a method of using the grown lead tungstate crystal in a closed PbF 2 High-temperature diffusion in the atmosphere, trying to use the thermal diffusion properties of substances at high temperatures to make PbWO 3 Crystal doping modification growth technology, this growth technology can make lead tungstate crystal obtain a part of PbF 2 Doping, but the thermal diffusion in the solid is very difficult, and the diffusion decreases significantly with the increase of the depth, PbF 2 The concentration in the crystal is low and the distribution is uneven
Therefore this PbF 2 :PbWO 4 There are two insurmountable difficulties in crystal growth technology: one is that the doped crystal cannot be guaranteed to obtain the required doping concentration; the other is that the PbF in the crystal 2 The distribution of doping concentration is not uniform, so it is difficult to grow high-quality PbF by this method 2 :PbWO 4 the crystal

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] a PbF 2 :PbWO 4 Crystal preparation method, comprises the steps:

[0019] (1) PbO and WO with a purity of 99.99% 3 and dopant PbF 2 After the solid powder is dried at about 150 °C, PbO and WO 3 Weighing according to the stoichiometric ratio, the dopant PbF 2 The molar concentration is 0.01%, and the weighed solid powder is pressed into a dense block solid under a pressure of 10Kpa, sintered in an oxidizing atmosphere at 750°C, and kept at a constant temperature of 1130°C for half an hour in a closed platinum crucible filled with oxygen to make it completely melt;

[0020] (2) Introduce the melted raw material into a growth crucible with a seed crystal to form a dense polycrystalline ingot, and place the growth crucible in a temperature-gradient method crystal growth furnace for inoculation and growth to obtain the finished product PbF 2 :PbWO 4 crystal; the temperature distribution curve in the temperature gradient method crystal growth furnace is as follows fi...

Embodiment 2

[0022] a Yb 2 o 3 :PbWO 4 Crystal preparation method, comprises the steps:

[0023] (1) PbO and WO with a purity of 99.99% 3 and dopant Yb 2 o 3 After the solid powder is dried at about 180 °C, PbO and WO 3 Weighing according to the stoichiometric ratio, the dopant Yb 2 o 3 The molar concentration is 0.05%, and the weighed solid powder is pressed into a dense block solid under a pressure of 30Kpa, sintered in an oxidizing atmosphere at 900°C, and kept at 1160°C for half an hour in a closed platinum crucible filled with oxygen to make it completely melt;

[0024] (2) Introduce the melted raw material into a growth crucible with a seed crystal to form a dense polycrystalline ingot, and place the growth crucible in a temperature-gradient method crystal growth furnace for inoculation and growth to obtain the finished product Yb 2 o 3 :PbWO 4 crystal; the temperature distribution curve in the temperature gradient method crystal growth furnace is as follows figure 2 It ...

Embodiment 3

[0026] a BaF 2 :PbWO 4 Crystal preparation method, comprises the steps:

[0027] (1) PbO and WO with a purity of 99.99% 3 and dopant BaF 2 After the solid powder is dried at about 200 °C, PbO and WO 3 Weighing according to the stoichiometric ratio, the dopant BaF 2 The molar concentration is 0.1%, and the weighed solid powder is pressed into a dense block solid under a pressure of 50Kpa, sintered in an oxidizing atmosphere at 1000°C, and kept at a constant temperature of 1200°C for half an hour in a closed platinum crucible filled with oxygen to make it completely melt.

[0028] (2) Introduce the melted raw material into a growth crucible with a seed crystal to form a dense polycrystalline ingot, and place the growth crucible in a temperature-gradient method crystal growth furnace for inoculation and growth to obtain the finished product BaF 2 :PbWO 4 crystal; the temperature distribution curve in the temperature gradient method crystal growth furnace is as follows fi...

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Abstract

The invention discloses a preparing method of doped lead tungstate crystal, which comprises the following steps: (1) drying PbO, WO3 with purity at 99.99% and solid powder of doping agent under 150-200 Deg C; weighing the PbO and WO3 according to chemical weight; setting the molar rate density of doping agent at 0.01-0.1%; pressing weighted solid powder into dense solid under 10-50Kpa; sintering in the oxidizing environment at 750-1000Deg C; aerating oxygen in the sealed platinum copple; insulating at 1130-1200 Deg C to fuse the solid; (2) introducing fused raw material into growing copple with seed to form dense multi-crystal ingot; placing the growing copple in the temperature-gradient crystal growing furnace to inoculate and grow with introducing speed at 1.0mm / h. The invention is fit for effumable doping agent, which is also fit for doping agent without effumability.

Description

technical field [0001] The invention relates to the field of crystal growth, in particular to a method for preparing doped lead tungstate crystals. Background technique [0002] The existing technology is relatively successful in growing lead tungstate and some oxides with relatively high melting point doping modified lead tungstate crystals, but it encounters difficulties in growing dopant doping with low melting point and strong volatility, because in these When growing crystals in the device, it is usually necessary to reserve a part of the upper part of the crystal raw material in the crucible to contain the oxygen needed for crystal growth. The temperature distribution in the crystal growth furnace is as follows: figure 1 As shown, the upper temperature is higher, the crystal growth raw material and the dopant are in a molten state, and doped with a non-volatile dopant such as La 2 o 3 The effect of the reserved space on crystal growth is not very obvious, but in the ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C30B29/32C30B11/00
Inventor 万尤宝刘俊星
Owner JIAXING UNIV
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