Transmission soft x-ray absorption spectroscopy by x-ray excited optical luminescence

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K05033
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Quantum beam science
• Research Institution: High Energy Accelerator Research Organization
• Principal Investigator: Horiba Koji 大学共同利用機関法人高エネルギー加速器研究機構, 物質構造科学研究所, 准教授 (10415292)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 放射光 / 軟X線吸収分光

Outline of Final Research Achievements

X-ray absorption spectroscopy (XAS) is widely used for revealing the chemical, electronic, and structural states of materials. The measurement of x-ray transmission through the samples is the most direct method for obtaining x-ray absorbance of the samples. However, in the soft-x-ray region, it is a hard task to measure the XAS spectra in transmission mode owing to the low transmittance of the soft x-ray in solids: Special setup of the samples is necessary for the measurement, such as thinning the samples up to around a few hundred nanometers or putting the samples on a membrane sample holder.
Recently, as a novel method of solving the difficulty, the XAS measurement in bulk-sensitive transmission mode on thin-film samples has been proposed, where the amount of transmission x-ray through the thin-film samples is measured by the intensity of x-ray excited optical luminescence (XEOL) from the substrates. We have developed a novel transmission XAS measurement system based on this method.

Free Research Field

X線分光

Academic Significance and Societal Importance of the Research Achievements

本研究により、転換可視蛍光収量による透過軟X線吸収分光法を様々な薄膜試料に適用可能な汎用的手法として確立することができた。これによって、特に表面が不安定な試料の軽元素の電子状態を計測する、学術的社会的にも非常に意義のある手法として発展が期待される。また本手法は汎用的な軟X線吸収分光法という位置付けに留まらず、軟X線領域におけるオペランド計測の新手法としても大きな展開が期待できる。
本測定装置は全国共同利用装置として広くユーザーに開放する予定であり、学術的のみならず産業的に重要な物質系やデバイス等、幅広い試料を対象として実験に供することで学術的社会的に貢献する。