What is ionizing radiation?

Release time:

2023-12-26

Ionizing radiation is a type of radiation that has enough energy to remove electrons from atoms. This type of radiation originates from unstable atoms, which are radioactive (referring to radioactive nuclides or isotopes) and release secondary and high-energy photons (gamma rays) from their nuclei to become more stable. This process is called radioactive decay. For example, naturally occurring nuclides such as radium, radon, uranium, and thorium exist in nature. Additionally, ionizing radiation is also released from human activities (such as atomic fission in nuclear reactors, ionization produced by electron accelerators, and artificially synthesized cobalt-60) and natural activities. During the decay process, the main products of radiation are alpha, beta, and gamma rays. X-rays are another type of radiation caused by electrons in the outer layers of atoms.

Definition of Ionizing Radiation

Ionizing radiation is a type of radiation with enough energy to remove electrons from atoms. This radiation originates from unstable atoms, which release secondary and high-energy photons (γ rays) as the atomic nucleus decays to become more stable. This process is known as radioactive decay. For example, naturally occurring radionuclides such as radium, radon, uranium, and thorium exist in nature. Additionally, ionizing radiation is also released from human activities (such as nuclear fission in reactors, ionization produced by electron accelerators, and artificially synthesized cobalt-60) and natural phenomena. During the decay process, the main products of radiation are α, β, and γ rays. X-rays are another type of radiation caused by electrons in the outer layers of atoms.

Alpha Particle

Alpha particles are positively charged high-energy particles (helium atoms) that quickly lose energy as they pass through a medium. They are typically emitted by some heavy atoms (such as uranium and radium) or some artificial radionuclides. Alpha particles travel through a medium, losing energy rapidly and cannot penetrate far. However, they can cause damage to tissues even if they do not penetrate deeply. Alpha particles are usually completely absorbed by the outer dead skin of the human body, and the radioactive isotopes they release do not pose a danger outside the body. However, if they are inhaled or injected, they can be very dangerous. Alpha particles can be blocked by a sheet of paper.

Beta Particle

Beta rays are charged particles that move at high speeds and are released from the radioactive decay of radionuclides. Humans are exposed to beta rays from both artificial sources and natural sources (such as tritium and C-14). Beta rays have greater penetrating power than alpha rays but cause less damage over the same distance. Some beta rays can penetrate the skin and cause radiological harm. However, once inside the body, they can cause greater harm. Beta particles can be reduced by clothing worn outside or completely blocked by a few millimeters of aluminum foil.

Gamma Particle

Like visible light and X-rays, gamma rays are a type of photon. During radioactive decay, gamma rays are released alongside alpha and beta rays. They carry no charge and have no mass but possess strong penetrating power. Natural radionuclides such as potassium-40 and artificial radionuclides like plutonium-239 and cesium-137 are major sources of gamma rays in the environment. Gamma rays can easily penetrate the human body and cause harm. Several feet of concrete can block gamma rays.

X-ray

X-rays are high-energy photons produced by the interaction of charged particles with matter. X-rays share many similar characteristics with gamma rays but originate differently. X-rays are caused by interactions outside the atom, while gamma rays originate from within the atom. X-rays have lower energy than gamma rays; therefore, their penetrating power is less than that of gamma rays. Thousands of X-ray machines are used daily in medicine and industry. X-rays are also used in cancer treatment to destroy cancerous cells. Due to their widespread use, X-rays are a source of artificial radiation. A few millimeters of lead can block X-rays.

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