2. Fundamentals of Radiation Physics

In physics, radiation is an energy that comes from a source and travels through a vacuum or through matter-containing media. Radiation is classified into two main categories, non-ionizing and ionizing, depending on its ability to ionize matter.

• Non-ionizing radiation.
  
  
• Ionizing radiation:
  • Directly ionizing radiation (charged particles): electrons, protons, α particles and heavy ions.
  • Indirectly ionizing radiation (neutral particles): photons (X rays and γ rays), neutrons.

Light, radio, and microwaves are types of radiation that are called non-ionizing. The kind of radiation discussed in this eLearning is called ionizing radiation, is a particular characteristic of the radiation produced when radioactive elements decay.

Classification of radiation