Development of positron age-momentum correlation measurement using ultra-short pulsed gamma rays and promotion of utilization research

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H03740
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 80040:Quantum beam science-related
• Research Institution: Institute for Molecular Science
• Principal Investigator: Taira Yoshitaka 分子科学研究所, 極端紫外光研究施設, 准教授 (60635803)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: ガンマ線 / トムソン散乱 / コンプトン散乱 / 陽電子消滅

Outline of Final Research Achievements

In this study, a positron age momentum correlation measurement using ultrashort pulsed gamma-rays (GiAMOC), which was originally developed by the principal investigator at the synchrotron radiation facility UVSOR, was developed. The maximum energy of the ultrashort pulsed gamma-rays is 6.6 MeV and the pulse width is 5 ps. The conventional positron age momentum correlation measurement is a complicated measurement system with analog modules, but in this study, a simple measurement system with a digital oscilloscope was successfully constructed. The measurement of multiple samples clearly showed that the energy spread of annihilation gamma rays changes with time, demonstrating the usefulness of GiAMOC.

Free Research Field

量子ビーム科学

Academic Significance and Societal Importance of the Research Achievements

陽電子消滅測定法は、結晶を構成する原子の一部が存在しない単原子空孔型欠陥や高分子中のsub-nm～数nm程度の微小空隙の測定を行える強力な手法である。本研究では、陽電子消滅測定法の一つであるGiAMOCの開発を行った。GiAMOCを用いることで、これまで困難であった厚さ数cmのバルク試料の測定や高温高圧など特殊環境下の試料の測定を行う事ができるようになる。