Yttrium-doped barium fluoride crystal and preparation method and use thereof

Patent metadata

Field	Value
Publication number	US-11142689-B2
Application number	US-201816619401-A
Country	US
Kind code	B2
Filing date	Apr 13, 2018
Priority date	Jun 5, 2017
Publication date	Oct 12, 2021
Grant date	Oct 12, 2021

Abstract

Disclosed are a yttrium-doped barium fluoride crystal and a preparation method and the use thereof, wherein the yttrium-doped barium fluoride crystal has a chemical composition of Ba(1−x)YxF2+x, in which 0.01≤x≤0.50. The yttrium-doped BaF2 crystal of the present invention has improved scintillation performance. The yttrium doping may greatly suppress the slow luminescence component of the BaF2 crystal and has an excellent fast/slow scintillation component ratio. The doped crystal is coupled to an optical detector to obtain a scintillation probe which is applicable to the fields of high time resolved measurement radiation such as high-energy physics, nuclear physics, ultrafast imaging and nuclear medicine imaging.

First claim

The invention claimed is:

1. A method for preparing an yttrium-doped barium fluoride scintillation crystal having a chemical composition of Ba (1−x) Y x F 2+x , wherein 0.01≤x≤0.50, and the method comprises the steps of:
weighing and mixing raw materials of YF 3 and BaF 2 according to the molar ratio BaF 2 :YF 3 =(1−x): x to obtain a mixed powder, wherein 0.01≤x≤0.50;
putting the mixed raw materials into crucibles in a vacuum furnace for thorough melting at a temperature of 1200 to 1400° C., and then cooling the mixture to obtain Ba (1−x) Y x F 2+x polycrystalline material, or subjecting the mixed powder to isostatic pressing, and putting the resulting substance into crucibles and sintering it at 900 to 1200° C. in vacuum to obtain sintered Ba (1−x) Y x F 2+x polycrystalline material; and
mixing the resulting polycrystalline material with an appropriate amount of PbF 2 powder, which is act as a deoxidizer, and growing crystals by vertical Bridgman method;
wherein the processes of the vertical Bridgman method include:
maintaining the furnace in a vacuum degree of less than 10 −3 Pa, melting the Ba (1−x) Y x F 2+x polycrystalline material and PbF 2 powder at 1200 to 1400° C., subjecting the resulting melt to crystal growth wherein the descending speed of the crucible is 0.5 to 4 mm/hour, and cooling the grown crystal to room temperature at a temperature decreasing rate of 10 to 50° C./hour;
wherein the deoxidizer PbF 2 is added in an amount of 0.5 to 5 wt % of the Ba (1−x) Y x F 2+x polycrystalline material.

2. The method of claim 1 , wherein the crucibles are high purity graphite crucibles or glassy carbon crucibles.

3. The method of claim 1 , wherein the deoxidizer PbF 2 is added in an amount of 0.5 to 2 wt % of the Ba (1−x) Y x F 2+x polycrystalline material.

4. The method of claim 1 , wherein the isostatic pressing is performed at a pressure of 5 to 20 MPa for 0.1 to 1 hour.

Assignees

• Shanghai Inst Ceramics Cas
• R&D Center Shanghai Inst Of Ceramics

Inventors

• Chen Junfeng
• Du Yong
• Wang Shaohua
• Sun Shiyun
• Zhou Xuenong
• Li Xiang

Classifications

• G01T1/2006

  using a combination of a scintillator and photodetector which measures the means radiation intensity · CPC title

• C30B15/00

  Single-crystal growth by pulling from a melt, e.g. Czochralski method (under a protective fluid C30B27/00) · CPC title

• C30B29/12 Primary

  Halides · CPC title

• C09K11/7705 Primary

  with alkali or alkaline earth metals · CPC title

• G01T1/2023

  Selection of materials · CPC title