New stage of astromaterial microanalysis with high-resolution X-ray spectrosocopy

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K18794
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 17:Earth and planetary science and related fields
• Research Institution: National Astronomical Observatory of Japan (2020); Japan Aerospace EXploration Agency (2018-2019)
• Principal Investigator: Mitsuda Kazuhisa 国立天文台, 先端技術センター, 特任教授 (80183961)
• Co-Investigator(Kenkyū-buntansha): 野口 高明 九州大学, 基幹教育院, 教授 (40222195)
• Project Period (FY): 2018-06-29 – 2021-03-31
• Keywords: 宇宙物質 / 元素微量分析 / 透過型電子顕微鏡 / EDS / 超高エネルギー分解能 / X線マイクロカロリメータ

Outline of Final Research Achievements

We developed a novel detector fabrication process in which energy resolution in a low energy range below about 1 keV is improved. We fabricated a new detector in house and validated the ability with experiments. The new detector can well separate low-energy emission lines from continuum, which is impossible with conventional semiconductor detectors. Using standard samples of minerals, we investigated damages of samples imposed by Scanning Transmission Electron Microscope with TES measurements. We confirmed that the effect of damage on the spectral measurements is negligibly small as far as the measurements were done within usual measurement time. We also investigated the stability of detector calibration data and the response function on time scale of a few days. We established the calibration strategy based on the results.

Free Research Field

宇宙物理学

Academic Significance and Societal Importance of the Research Achievements

TES型X線マイクロカロリメータアレイ検出器は，従来の半導体検出器に比べると50倍程度優れたエネルギー分解能を持ち，物質分析への応用も期待されている。しかし，検出効率や最大計測率等の制限からが高い分解能を得るには注意が必要である。また性能の時間変化も懸念される。本研究は，今後重要になると予想されるボロンから酸素のK線を含む低エネルギー帯におけるエネルギー分解能を，10keVまでの高エネルギー帯の性能を犠牲にせずに高めることに成功し，計測による試料へのダメージを含めた実分析に向けた知見を取得した。本研究成果により，超高エネルギー分解能のX線マイクロ解析の実利用への道が拓くことが期待される。