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Lanthanum-doped barium fluoride crystal and preparing method thereof

A barium fluoride and lanthanum doping technology is applied in the field of lanthanum doped barium fluoride crystal and its preparation, which can solve problems such as difficulty in large size, and achieve the effects of large size and improving work efficiency.

Inactive Publication Date: 2019-05-21
HUAIAN HONGXIANG PHOTOELECTRIC TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the crucible drop method is used for the growth of barium fluoride crystals. The growth method is carried out in a furnace structure composed of graphite as a crucible, graphite resistance heating, and graphite and molybdenum sheet assembly as a heat preservation screen. The seed crystal is placed in The bottom or upper part of the crucible, when the crystal grows and crystallizes, it is generally crystallized gradually in a spiral shape. The crucible descending method grows the crystal. Due to the distribution limitation of the radial temperature gradient, it is relatively difficult to obtain a large size. Generally, barium fluoride crystals can only Grow around Φ3-4 inches

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] a 0.5% BaF 2 (La) preparation method of crystal, comprises the following steps:

[0028] S1. Preparation of pellets: Weigh the bulk density to be 0.5g / cm 3 , 85kg of high-purity 99.99% barium fluoride powder and 1.275kg of lead fluoride with a mass percentage of 1.5% are mixed and stirred evenly, and the vacuum pump is turned on to vacuumize to 5.0×10 -2 At Pa, heat up to 800°C at a rate of 100°C / h, keep for 2h, then raise the temperature to 1370°C at a rate of 50°C / h, keep for 4h, turn off the vacuum pump, and then turn off the power when the temperature drops to 150°C to obtain barium fluoride Granular material, this step can increase the packing density of raw materials, which is beneficial to save space;

[0029] S2. Mixing of raw materials: 425g of lanthanum fluoride with a mass percentage of 0.5% is added to the barium fluoride pellets, and the bulk density is 2.4g / cm 3 , stir evenly;

[0030] S3. Placement of seed crystal: Put the uniformly mixed raw material...

Embodiment 2

[0039] a 0.5% BaF 2 (La) preparation method of crystal, comprises the following steps:

[0040] S1. Preparation of pellets: Weigh the bulk density to be 0.8g / cm 3 , 85kg of high-purity 99.99% barium fluoride powder and 1.275kg of lead fluoride with a mass percentage of 1.5% are mixed and stirred evenly, and the vacuum pump is turned on to vacuumize to 5.0×10 -2 At Pa, heat up to 800°C at a rate of 100°C / h, keep for 2h, then raise the temperature to 1400°C at a rate of 50°C / h, keep for 4h, turn off the vacuum pump, and then turn off the power when the temperature drops to 150°C to obtain barium fluoride Granular material, this step can increase the packing density of raw materials, which is beneficial to save space;

[0041] S2. Mixing of raw materials: 425g of lanthanum fluoride with a mass percentage of 0.5% is added to the barium fluoride pellets, and the bulk density is 2.4g / cm 3 , stir evenly;

[0042] S3. Placement of seed crystal: Put the uniformly mixed raw material...

Embodiment 3

[0051] a 0.5% BaF 2 (La) preparation method of crystal, comprises the following steps:

[0052] S1. Preparation of pellets: Weigh the bulk density to be 0.6g / cm 3 , 85kg of high-purity 99.99% barium fluoride powder and 1.275kg of lead fluoride with a mass percentage of 1.5% are mixed and stirred evenly, and the vacuum pump is turned on to vacuumize to 5.0×10 -2 At Pa, heat up to 800°C at a rate of 100°C / h, keep for 2h, then raise the temperature to 1380°C at a rate of 50°C / h, keep for 4h, turn off the vacuum pump, and then turn off the power when the temperature drops to 150°C to obtain barium fluoride Granular material, this step can increase the packing density of raw materials, which is beneficial to save space;

[0053] S2. Mixing of raw materials: 425g of lanthanum fluoride with a mass percentage of 0.5% is added to the barium fluoride pellets, and the bulk density is 2.4g / cm 3 , stir evenly;

[0054] S3. Placement of seed crystal: Put the uniformly mixed raw material...

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Abstract

The invention provides a lanthanum-doped barium fluoride crystal and a preparing method thereof and relates to the technical field of crystal preparation. The crystal includes barium fluoride and lanthanum fluoride the mass percentage of which is 0.2-1%. The preparation steps include particle preparation, raw material mixing, seed crystal standing, and crystal growth which are five stages. A heatexchange manner is adopted to prepare the lanthanum-doped barium fluoride crystal, the temperature gradient in the preparation process is strictly controlled, and lanthanum-doped barium fluoride scintillation crystals having a diameter of 380 mm can be produced, and in the same production period, and the output of crystals in a single furnace from 100 kg of raw materials is increased from 30 kg to80-100 kg, thus increasing the working efficiency.

Description

technical field [0001] The invention relates to the technical field of crystal preparation, in particular to a lanthanum-doped barium fluoride crystal and a preparation method thereof. Background technique [0002] Barium fluoride (BaF 2 ) crystal has strong light transmission ability at 140-1200nm, and has the characteristics of high light transmittance, good temperature resistance of refractive index, small water absorption and large yield stress. It is a kind of high-quality laser window material, and it is one of the few One of the fast scintillation crystals, it also has a slow component with an emission wavelength of 315nm and a decay time of 630ns. The proportion of this slow component in the entire light output is sometimes as high as 80%-90%. High count measurement will cause serious signal accumulation, resulting in the dead time of the readout system, so how to suppress the proportion of slow components in the crystal becomes the key to the practical application ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B29/12C30B11/00
Inventor 沈琨沈承刚
Owner HUAIAN HONGXIANG PHOTOELECTRIC TECH