Method for growing cerium fluoride crystal by non-vacuum descent process

A cerium fluoride, non-vacuum technology, applied in the field of growing CeF3 crystals, can solve the problems of high cost, low efficiency, and restrictions on the development and application of CeF crystals, and achieve the effect of removing oxygen impurities and simplifying the growth process

Inactive Publication Date: 2015-10-14
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

But since CeF 3 It is very easy to be oxidized, so the current growth technology, whether it is the descending method or the pulling method, usually uses high vacuum or a protective atmosphere in a closed

Method used

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  • Method for growing cerium fluoride crystal by non-vacuum descent process
  • Method for growing cerium fluoride crystal by non-vacuum descent process
  • Method for growing cerium fluoride crystal by non-vacuum descent process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] In an environment with a temperature of 20°C and a relative humidity of 6.5%, 100 g of CeF with a purity of 99.9% 3 Mix the powder with 3g polytetrafluoroethylene powder evenly; put the mixed raw materials into a quartz glass container, put them in a vacuum oven, and perform vacuum drying at 300°C for 3 hours; put the dried raw materials into a In a platinum crucible with crystal taper and sealed, crystal growth is carried out under non-vacuum conditions: first heat the crucible to 1460 ° C, keep warm to fully melt the raw materials in the crucible (about 3 hours), and then at a rate of 1 mm / hour, 30 The temperature gradient of ℃ / cm was used for crystal growth; after the growth was completed, the temperature was lowered to room temperature at a rate of 30 ℃ / hour.

[0032] figure 1 For the CeF obtained in this embodiment 3 crystal blank, figure 2 The CeF obtained by the method described in this embodiment 3 Crystal samples, from figure 1 with figure 2 Visible: Ce...

Embodiment 2

[0036] In an environment with a temperature of 20°C and a relative humidity of 20%, 100 g of CeF with a purity of 99.9% 3 Mix the powder with 5g polytetrafluoroethylene powder evenly; put the mixed raw materials into a quartz glass container, put them in a vacuum oven, and carry out vacuum drying at 350°C for 1 hour; put the dried raw materials into a In a platinum crucible with crystal taper and sealed, crystal growth is carried out under non-vacuum conditions: first heat the crucible to 1470 ° C, keep warm to fully melt the raw materials in the crucible (about 5 hours), and then at a descending speed of 1.5 mm / hour, 40 The temperature gradient of ℃ / cm was used for crystal growth; after the growth was completed, the temperature was lowered to room temperature at a rate of 25 ℃ / hour.

[0037] CeF obtained in this embodiment 3 The crystal is transparent and complete, and has the XRD spectrum and X-ray excitation luminescence spectrum described in Example 1.

Embodiment 3

[0039] In an environment with a temperature of 20°C and a relative humidity of 15%, 100 g of CeF with a purity of 99.9% 3 Mix the powder with 1g of polytetrafluoroethylene powder evenly; put the mixed raw materials into a quartz glass container, put them in a vacuum oven, and carry out vacuum drying treatment at 150 °C for 5 hours; put the dried raw materials into a In a platinum crucible with crystal taper and sealed, crystal growth is carried out under non-vacuum conditions: first heat the crucible to 1480 ° C, keep warm to fully melt the raw materials in the crucible (about 5 hours), and then at a descending speed of 0.5 mm / hour, 60 Crystal growth was carried out with a temperature gradient of °C / cm; after the growth was completed, the temperature was lowered to room temperature at a rate of 35 °C / h.

[0040] CeF obtained in this embodiment 3 The crystal is transparent and complete, and has the XRD spectrum and X-ray excitation luminescence spectrum described in Example 1....

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Abstract

The invention discloses a method for growing a cerium fluoride crystal by a non-vacuum descent process. The method comprises the following steps: a) uniformly mixing cerium fluoride powder and polytetrafluoroethylene powder at a mass ratio of 100:(1-5); b) performing vacuum drying of the mixed powder obtained in the step a); and c) putting the dried mixed powder obtained in the step b) into a crucible, and performing crystal growth at a descent rate of 0.5-1.5mm/h in a non-vacuum condition. According to the method disclosed by the invention, the oxygen impurity can be effectively cleared by adding certain amount of polytetrafluoroethylene powder, thus the growth of CeF3 crystal using the Bridgman method in a non-vacuum condition is realized, the growth technology of CeF3 crystal is greatly simplified, and large-scale production of CeF3 crystal is facilitated; and compared with the prior art, the method has remarkable progress and practical value.

Description

technical field [0001] The invention relates to a method for growing CeF by using a crucible drop method under non-vacuum conditions 3 A crystal method belongs to the technical field of artificial crystal growth. Background technique [0002] In the early 1990s, CeF 3 Crystals have attracted widespread attention due to their high density, fast response and excellent scintillation properties. They were once one of the main candidate materials for detectors used in the Large Hadron Collider (LHC) at the Western European Nuclear Center (CERN). However, due to its poor growth reproducibility and high cost, CERN finally abandoned CeF in 1995. 3 crystal and chose lead tungstate (PbWO 4 ) crystals as the core material for compact muon coil (CMS) detectors, CeF 3 Crystals are only used as base material for CMS. [0003] With the LHC in operation, PbWO 4 Pb and W elements in the crystal, because the atomic number Z is greater than 71, high-energy protons and mesons can cause a ...

Claims

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Application Information

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IPC IPC(8): C30B29/12C30B11/00
Inventor 岳世海朱勇王威殷学技徐海芳潘裕柏葛增伟
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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