講座

X線分光の現在
III.　蛍光X線ホログラフィー

Modern X-ray Spectroscopy
III. X-ray Fluorescence Holography

林 好一
Kouichi HAYASHI

蛍光X線ホログラフィーは，蛍光X線を発する原子の周りの三次元原子配置を一義的に決定できる比較的新しい構造解析手法である．本手法の特徴は，結晶などにX線を照射した際に発生する蛍光X線の強度変調を測定することにより，散乱X線の位相と強度両者を記録することにある．本稿では，蛍光X線ホログラフィーの原理，実験装置，データ処理，異常散乱やX線ルミネッセンスを応用した測定，鉄合金中の微量銅の測定例について述べる．

X-ray fluorescence holography (XFH) provides three dimensional atomic images around specified elements. The XFH uses atoms as a wave source or monitor of interference field within a crystal sample, and therefore it can record both intensity and phase of scattered X-rays. Its current performance makes it possible to apply to ultra thin film, impurity and quasicrystal. In this article, I show the theory including solutions for twin image problem, advanced measuring system, data processing for reconstruction of the atomic images and for obtaining accurate atomic positions, applications using resonant X-ray scattering and X-ray excited optical luminescence, and an example of XFH result on the local structure around copper in silicon steal.

Keywords: X-ray fluorescence holography, X-ray holography, X-ray scattering, single crystal, impurity