What is radiation?

Radiation is a phenomenon of transfer energy in space by particles or photons. 

Examples of radiation: Visible light, Laser, UV, X-RAY.

What is ionizing radiation?

When radiation has enough high energy, it can cause electrons to be removed from the atoms in material. The process of electron extraction is called ionization and therefore radiation is called ionizing radiation.

Ionizing radiation is emitted from various natural and artificial sources.

Examples of ionizing radiation: Alfa, Beta, Gama, Xray, Neutrons and Natural cosmic radiation.