Here an electron undergoes more than 20 scattering events as it passes through a specimen. This would only occur on rare occasions, e.g. with very thick or dense specimens.
入射電子射向物質時,會多次受到物質中多個電子或原子核的散射(即多次散射),從而使得入射電子在遭到多次碰撞以後,其在各個方向上的散射機率趨於一致。由於散射截面與原子序數的平方成正比,因而對於輕元素,其散射的機率要小於重元素。
![原子核-模型圖](/img/b/a95/nBnauM3X2EzM5UTNyQTO1QTM0MTM2MDO0YTMxADMwAzMxAzL0kzL0UzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![電子-模型圖](/img/a/4e2/nBnauM3X4YzM1MzNwcTO1QTM0MTM2MDO0YTMxADMwAzMxAzL3kzL3QzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)