• Top Page
• Basics of Ionizing Radiation – Types of Radiation

Basics of Ionizing Radiation

Types of Radiation

Alpha (α) Ray
Alpha (α) rays are a flow of helium (He) nuclei moving at a high speed. They have weak ability to pass through objects and can be blocked even by a single sheet of paper. However, their ionization effect is large in the area where they hit.
Alpha rays that are blocked and stopped comprise helium, which is the same gas found in floating balloons.

Beta (β) Ray
Beta (β) rays are a flow of sub-atomic particles called electrons that move at a high speed and have a negative charge. They can be blocked by a thin metal plate, such as aluminum. As they are ~7000 times lighter than alpha particles, the ionization effect at the point of impact is small.
Blocked beta rays eventually stop and are absorbed by materials, mixing with other electrons that they contain previously.

Gamma (γ) Ray
Gamma (γ) rays are a type of electromagnetic wave that travels through space and objects, similar to light and radio waves. However, they can be blocked by a thick plate of lead or iron.
As they pass through an object, their strength gradually reduces, and they eventually disappear.

Neutron Ray
Neutron rays are a flow of uncharged particles called neutrons that make up atomic nuclei. They have strong tendency to pass through materials but can be blocked by water and concrete.
As they collide with other nuclei in a material, they are eventually absorbed by the nuclei of surrounding atoms; furthermore, depending on the type of nucleus, atoms may become radioactive.