Study of chemical reactions of negative molecular ions in the space environment probed by the state-of-the-art neutral molecule detector

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K15238
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 32010:Fundamental physical chemistry-related
• Research Institution: Tokyo Metropolitan University (2021-2022); Institute of Physical and Chemical Research (2020)
• Principal Investigator: Okumura Takuma 東京都立大学, 理学研究科, 助教 (70855030)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 超伝導検出器 / 中性分子検出器 / イオン蓄積リング / 負イオン

Outline of Final Research Achievements

The purpose of this study is to develop a new experimental apparatus for directly observing photochemical reactions of negative ions in the space environment by combining a cryogenic electrostatic ion storage ring developed in RIKEN (RICE) and state-of-the-art superconducting transition-edge microcalorimeters (TES) for detecting neutral molecules produced by the reactions. This was the first attempt to employ a TES as a neutral-molecule detector. By thoroughly reducing effects of black-body radiations, I succeeded in demonstrating neutral-molecule detections by the TES, particularly observing dissociation processes of diatomic molecular ions. However, a mass resolution of the TES detector is still not sufficient for measurements of general chemical reactions of negative molecular ions, and further improvements are currently underway.

Free Research Field

原子分子物理

Academic Significance and Societal Importance of the Research Achievements

中性分子を高質量分解能検出する技術はこれまでいくつか考案されているが、適用可能な分子が限定されるなど問題点も多く、汎用的で高質量分解な中性分子検出法が長く切望されてきた。本研究で原理実証に成功したTESによる中性分子検出器は、適用可能な分子に制限はなく、更なる分解能の向上を実現できれば汎用中性分子検出器として極めて有望である。本研究による新たな中性分子検出技術の確立は、化学反応の実験研究の常識を一変させることに繋がり、また基礎物理化学を超えて工学や生物学など広く他分野にまで影響が波及することが期待できる。