• Search Research Projects
  • Search Researchers
  • How to Use
  1. Back to project page

2021 Fiscal Year Final Research Report

Ralation between cation vacancy and persisitent phosphorescence in Ce:GAGG crystals studied by positron annihilation spectroscopy

Research Project

  • PDF
Project/Area Number 19K04997
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 26020:Inorganic materials and properties-related
Research InstitutionYamagata University

Principal Investigator

Kitaura Mamoru  山形大学, 理学部, 教授 (60300571)

Co-Investigator(Kenkyū-buntansha) 鎌田 圭  東北大学, 未来科学技術共同研究センター, 准教授 (60639649)
石崎 学  山形大学, 理学部, 講師 (60610334)
Project Period (FY) 2019-04-01 – 2022-03-31
Keywordsシンチレータ / 陽電子消滅分光 / 原子空孔 / 長寿命発光 / 格子欠陥
Outline of Final Research Achievements

In the present study, positron annihilation lifetime spectroscopy using ultrashort gamma-ray pulses (GiPALS) has revealed the existence of defect pairs of cationic vacancies and oxygen vacancies, which are responsible for the degradation of Ce:GAGG scintillators. It was found that defect complexwes of antisite defects and oxygen vacancies are introduced as charge compensators for the cationic vacancy charges, causing useless long-lived emission in the scintillator. The codoping method was effective in suppressing the defect complexes. Practically, when magnesium was cooped, the cationic vacancies disappeared. The long-lived luminescence and electron trapping centres were also significantly suppressed by magnesium codoping.

Free Research Field

物性物理学

Academic Significance and Societal Importance of the Research Achievements

現在、放射線の有効かつ安全安心な利用が求められており、そのためには放射線検出器の心臓部であるシンチレータの開発が必要不可欠である。本研究の成果は、(1) 広く利用されているCe:GAGGシンチレータの高性能化を実現するには結晶育成時に導入される原子空孔を抑制する必要があること、(2) そのためには不純物の共賦活が有効であること、を発見したことである。超短パルスガンマ線を用いた陽電子消滅寿命分光(GiPALS)によって初めて達成できた成果であり、GiPALSは良質のシンチレータを得るために最良の分析評価方法となりうる。

URL: 

Published: 2023-01-30  

Information User Guide FAQ News Terms of Use Attribution of KAKENHI

Powered by NII kakenhi