Development of multi isotopologues analysis by mid-infrared frequency comb assisted cavity enhanced laser spectroscopy

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K15205
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 31010:Nuclear engineering-related
• Research Institution: The University of Tokyo (2021-2022); Nagoya University (2020)
• Principal Investigator: Terabayashi Ryohei 東京大学, 大学院工学系研究科(工学部), 助教 (10870272)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: レーザー分光 / 同位体分析 / 放射性核種分析 / 光周波数コム / 光共振器

Outline of Final Research Achievements

In this study, a highly sensitive laser absorption spectroscopy was developed in order to simultaneously analyze molecular species including long half-life radionuclides and various isotopes without complicated pretreatment and chemical separation, utilizing a mid-infrared optical frequency comb and a highly reflective optical resonator. Particularly, a linewidth reduction technique of a mid-infrared semiconductor laser was developed as well as a system of laser frequency monitoring and stabilization using the mid-infrared optical frequency comb. Finally, a successful demonstration of the acquisition of absorption spectra of multiple gas molecules was performed by combining these methods. This has enabled us to establish the basis for a technology to simultaneously acquire high-intensity mid-infrared absorption spectra of multiple molecular species including low-abundance long half-life radionuclides.

Free Research Field

原子力工学

Academic Significance and Societal Importance of the Research Achievements

長半減期放射性核種は、世代を超えた長期間に及ぶ影響が懸念され、多様な分子・化学形態で環境中を循環する。一方、このような核種を分析するためには、従来、核種や化学形に応じてそれぞれを化学的に分離してそれぞれ分析する必要があった。これに対し、本研究で開発を進めた手法は、様々な分子種由来の光吸収を同時取得でき、多様な分子種の同時分析を実現できる可能性がある。今後、さらなる研究開発が進めば、原子力分野における核種分析、核種モニタリングの効率化・高速化につながるとともに、これまでにない同位体分析法として、様々な研究・産業領域への適用が期待でき、新たな知見創出の一助となることが期待できる。