Summary:
- The various emissions will differ considerably in their ability to go through matter, known as their penetrating ability.
- The α-particle has the least penetrating power since it is the largest and slowest emission.
- Beta particles are more penetrating than alpha particles, but can be stopped by a thin sheet of aluminum.
- Of the three basic types of emissions, gamma particle are the most penetrating.
- A thick lead shield is required to stop gamma emissions.
- Positrons represent a special case in that they annihilate when they come in contact with electrons.