As for their penetrating power, beta particles are typically stopped by a few millimeters of aluminum.

至于它们的穿透力，β 粒子通常会被几毫米的铝挡住。

Gamma rays have the highest penetrating power, requiring large amount of concrete or lead to stop their propagation.

伽马射线具有最高的穿透力，需要大量的混凝土或铅才能阻止其传播。

Later scientists studied such decays and categorized the emitted rays or particles into three different groups, based on their penetrating power.

后来的科学家研究了这种衰变，并根据它们的穿透力将发射的射线或粒子分为三类。

But alpha particles have the least penetrating power of the three groups – they’re barely able to pass through a piece of paper.

但是 α 粒子的穿透力是这三组粒子中最小的——它们几乎无法穿过一张纸。