Development of a positron annihilation apparatus with sub-mm space resolution for the detection of nm-size open volume

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K18812
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 26:Materials engineering and related fields
• Research Institution: University of Tsukuba
• Principal Investigator: Uedono Akira 筑波大学, 数理物質系, 教授 (20213374)
• Project Period (FY): 2021-07-09 – 2023-03-31
• Keywords: ナノ空隙 / 陽電子消滅 / サブミリメートル空間分解能

Outline of Final Research Achievements

A positron is the antimatter of an electron, and when it enters a solid, it annihilates with an electron and emits γ-rays. From measurements of the energy distribution of annihilation γ-rays and the positron lifetime, vacancy-type defects and open spaces (single atomic vacancies to nanometer-sized voids) can be detected nondestructively and with high sensitivity. The purpose of this study is to develop a positron annihilation experimental apparatus with spatial resolution on the order of sub-millimeter and to clarify the behavior of open spaces in polymers. In collaborations with research institutions and companies, relationships between free volumes in engineering plastics and their thermal properties or impacts of stress or temperature on free volumes were studied using the technique developed by this program.

Free Research Field

陽電子科学

Academic Significance and Societal Importance of the Research Achievements

陽電子消滅を用いて自由体積を感度よく非破壊、かつサブミリメートル程度の分解能で測定できる装置を開発した。本装置を用いてエンジニアリング・プラスチック、炭素繊維複合材料（CFRP）等の評価を実施した。これらの材料は、精密機器機械部品、一般産業用機械部品、医療機器用部品、スポーツ用品などの分野で使用されており、材料の自由体積と材料特性の関係を評価することは大きな意義がある。本研究により、上記装置をもって企業や各種の研究所と共同研究し、材料開発を支援することが可能となった。