Method for improving scintillation property of cerium-doped LYSO crystals grown through Bridgman-Stockbarger method

A crucible descending method, yttrium lutetium silicate technology, applied in the direction of single crystal growth, crystal growth, single crystal growth, etc., can solve the problems of poor light output scintillation performance, unusable, crystal oxygen deficiency, etc., to optimize the scintillation performance, The effect of reducing color center absorption and increasing light output

Active Publication Date: 2016-01-06
成都东骏激光股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because the crystal is grown in a reducing atmosphere, there is a serious lack of oxygen in the crystal, and the scintillation performance such as light output and energy resolution is very poor, and it is almost unusable.

Method used

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  • Method for improving scintillation property of cerium-doped LYSO crystals grown through Bridgman-Stockbarger method
  • Method for improving scintillation property of cerium-doped LYSO crystals grown through Bridgman-Stockbarger method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] (1) Put the cerium-doped yttrium silicate crystal into a high-temperature atmosphere furnace, first evacuated to below 10KPa, and then slowly filled with high-purity nitrogen;

[0022] (2) Heating stage: the crystal sample is heated from room temperature to 400°C at a rate of 80°C / h, then heated to 800°C at a rate of 100°C / h, and then heated to 1250°C at a rate of 60°C / h;

[0023] (3) Constant temperature stage: the crystal is kept constant at the highest temperature for 80 hours, and the color changes from off-white to colorless and transparent;

[0024] (4) Cooling stage: After the constant temperature process is over, slowly drop to 900°C at a rate of -60°C / h, then drop to 600°C at a rate of -80°C / h, and finally drop at a rate of -100°C / h to room temperature.

[0025] The comparison test before and after shows that: the number of channels before the crystal is 159, and the number of channels is increased to 578 after high temperature heat treatment, and the flicker ...

Embodiment 2

[0027] (1) Put the cerium-doped yttrium silicate crystal into a high-temperature atmosphere furnace, first evacuated to below 10KPa, and then slowly filled with nitrogen and oxygen, wherein the volume percentage of oxygen is 10%;

[0028] (2) Heating stage: the crystal sample is heated from room temperature to 400°C at a rate of 80°C / h, then heated to 800°C at a rate of 100°C / h, and then heated to 1200°C at a rate of 60°C / h;

[0029] (3) Constant temperature stage: the crystal is kept at a constant temperature for 100 hours at the highest temperature, and the color changes from yellowish to colorless and transparent;

[0030] (4) Cooling stage: After the constant temperature process is over, slowly drop to 900°C at a rate of -60°C / h, then drop to 600°C at a rate of -80°C / h, and finally drop at a rate of -100°C / h to room temperature.

[0031] The comparison test before and after shows that: the number of channels before the crystal is 163 without treatment, and the number of c...

Embodiment 3

[0033] (1) Put the cerium-doped yttrium silicate crystal into a high-temperature atmosphere furnace, first evacuated to below 10KPa, and then slowly filled with nitrogen and oxygen, wherein the volume percentage of oxygen is 25%;

[0034] (2) Heating stage: the crystal sample is heated from room temperature to 400°C at a rate of 80°C / h, then heated to 800°C at a rate of 100°C / h, and then heated to 1300°C at a rate of 60°C / h;

[0035] (3) Constant temperature stage: the crystal is kept at a constant temperature for 60 hours at the highest temperature, and the color changes from light brown to colorless and transparent;

[0036] (4) Cooling stage: After the constant temperature process is over, slowly drop to 900°C at a rate of -60°C / h, then drop to 600°C at a rate of -80°C / h, and finally drop at a rate of -100°C / h to room temperature.

[0037] The comparison test before and after shows that the number of channel sites before the crystal is 157 without treatment, and the number...

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Abstract

The invention discloses a method for improving the scintillation property of cerium-doped LYSO crystals grown through a Bridgman-Stockbarger method. The crystals are subjected to high-temperature thermal treatment under a neutral or oxidizing atmosphere condition, so that the crystals are transformed into colorless and transparent from a sandy color or other colors, and meanwhile the scintillation property the crystals is obviously improved. It is shown through testing results that the transmittance of the crystals at 420 nm is 83.5%, the optimal light output is 36,000+ / -1,000 photons / MeV, and the fall time is 42.9 ns. The comprehensive performance of the crystals reaches the advanced level at home and abroad.

Description

technical field [0001] The invention relates to the field of crystal materials, in particular to a method for improving the scintillation performance of a cerium-doped yttrium lutetium silicate crystal grown by a crucible descending method. Background technique [0002] Cerium-doped yttrium silicate crystal (LYSO:Ce) is a new type of scintillation crystal with excellent comprehensive properties. Its main features include: high light yield, up to 75% of NaI (Tl) crystal; short fluorescence decay time, about 40ns; The fluorescence emission peak is within the detection sensitivity range of the photomultiplier tube, and has good detection efficiency for γ-rays; high energy resolution; stable chemical properties, no deliquescence, and good mechanical strength. Based on the above characteristics, LYSO:Ce crystals have broad application prospects in high-energy physics, nuclear medicine, industrial CT, security inspection and other fields, and have been gradually applied in nuclear...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B33/02C30B29/22
Inventor 周世斌王桂素沈定中
Owner 成都东骏激光股份有限公司
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