Radiation

Radiation refers to the emission and propagation of energy through space or a material medium in the form of waves or particles. It can occur in various forms, ranging from electromagnetic radiation, including light, X-rays, and ultraviolet (UV) radiation, to particle radiation such as alpha and beta particles emitted from radioactive materials.

Van Allen radiation belt

Patient prepared for radiation therapy

Penetrating power of different types of radiation - alpha, beta, gamma and neutrons

Radiation_beam_to_chest

Types of Radiation

Radiation is commonly categorized into two types: non-ionizing and ionizing radiation.

• Non-ionizing radiation includes forms of electromagnetic radiation that do not carry enough energy to ionize atoms or molecules. Examples include microwaves, radio waves, and visible light.
• Ionizing radiation carries enough energy to remove tightly bound electrons from atoms, thus creating ions. It includes X-rays, gamma rays, and particle radiation from radioactive decay.

Electromagnetic Radiation

Electromagnetic radiation is a form of energy that is produced by oscillating electric and magnetic fields and travels through space at the speed of light. This category encompasses a wide spectrum of radiation, from very long radio waves to very short gamma rays.

Particle Radiation

Particle radiation consists of subatomic particles, such as electrons, protons, neutrons, or alpha particles, emitted at high speeds from unstable atoms or nuclear reactions.

Sources of Radiation

Radiation can be derived from both natural and artificial sources. Natural background radiation comes from cosmic rays, radioactive materials in the earth, and naturally occurring radioactive substances within the human body. Artificial radiation sources include medical X-rays, nuclear power plants, and consumer products like smoke detectors and television sets.

Effects of Radiation on Human Health

The biological effects of radiation depend on the type and amount of radiation exposure. Non-ionizing radiation is generally considered less harmful to living tissue, while ionizing radiation can damage biological tissues, leading to skin burns, radiation sickness, cancer, and, at very high doses, death.

Glossary

• Electromagnetic radiation - A form of energy that is propagated through space or through a material medium in the form of electromagnetic waves.
• Ionizing radiation - Radiation with enough energy to remove tightly bound electrons from atoms, creating ions.
• Non-ionizing radiation - Radiation without enough energy to cause ionization in the matter it interacts with.
• Alpha particles - Positively charged particles consisting of two protons and two neutrons, emitted by certain radioactive materials.
• Beta particles - High-energy, high-speed electrons or positrons emitted by certain types of radioactive nuclei.
• Gamma rays - Penetrating electromagnetic radiation of a kind arising from the radioactive decay of atomic nuclei.
• X-Rays - A form of electromagnetic radiation, similar to light but of shorter wavelength and capable of penetrating solids and ionizing gases.
• Cosmic rays - Extremely high-energy radiation, mainly originating outside the Solar System.
• Radioactive decay - The process by which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves.
• Radiation sickness - Illness and symptoms resulting from excessive exposure to ionizing radiation.
• Cancer - A disease characterized by the uncontrolled division of abnormal cells in a part of the body.
• Radiation therapy - The use of ionizing radiation to treat cancer by killing cancerous cells or slowing their growth.
• Ultraviolet radiation - A form of electromagnetic radiation with wavelength shorter than that of visible light but longer than X-rays.

Radiation Resources
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