弾性散乱電子

elastically scattered electron

[目次：理論(電子の散乱／回折／結像)]

入射電子が試料を構成する原子と衝突し進行方向を変える（散乱）とき、そのエネルギーを失わずに散乱される電子。試料が結晶の場合、弾性散乱された電子はブラッグ条件で与えられる特定の方向にのみ観測される。その電子波を回折波という。試料が薄い場合は、TEM像や回折図形の強度は弾性散乱電子で説明ができる。試料が厚くなると(～10nm以上)、非弾性散乱電子の影響を考慮しなければならない。

Elastically scattered electrons are defined as the electrons which are scattered (change in their traveling direction) by constituent atoms in a specimen without losing their energy. When a specimen is a crystal, elastically scattered electrons become diffracted waves that travel in specific directions given by the Bragg condition. As a specimen is thinner, the intensity of a TEM image or a diffraction pattern is explained by elastically scattered electrons. As a specimen is thicker (～10 nm or thicker), the effect of inelastically scattered electrons must be taken into account.

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