May 29, 2022

Radiation (French: rayonnement, German: strahlung, English: radioactive rays, Spanish: radiación) is the process by which particles or waves propagate through a medium or space, a flow of energy. Radiation includes naturally occurring radiation and artificially created radiation. Artificial radiation is artificially generated radiation and is widely used from X-ray imaging in the medical field to industrial sites, seed improvement, and pest control. Radioactivity is the strength of a radioactive material to emit radiation.

Type of radiation

Radiation can be largely divided into ionizing radiation (ionizing radiation) and non-ionizing radiation (non-ionizing radiation).

Ionizing radiation (ionizing radiation)

Ionizing radiation is radiation that can ionize (ionize) particles by separating them from molecules. Alpha-rays include ultraviolet rays, alpha rays, beta rays, X-rays, and gamma rays. Normal radiation refers to ionized radiation (ionizing radiation).

Alpha rays

Alpha particles are high-velocity helium nuclei emitted by several high atomic number radionuclides (eg plutonium, radium, uranium): with low transmittance (less than 0.1 mm), not a single sheet of paper can pass through. If a radiation source enters the body in large amounts (wound skin, breathing, oral intake, etc.), the human body may be damaged. Radon gas (Rn-222) is a radiation source that emits alpha rays. It is a helium nucleus in which two protons and two neutrons are combined as a flow of alpha particles that come out with the alpha decay of a radioactive element. The ionization is strong, and when passing through a substance, many ions are generated along the path. The penetrating power is very weak, and 5 million eV of alpha ray stops even if it passes 3 cm through 1 atm (atm) of air.

Beta rays

Beta particles are high-energy electrons emitted from the nucleus of an unstable atom (eg, cesium-137, iodine-131). While these particles can penetrate the skin, they cannot penetrate metals such as aluminum. If the energy is large, it can damage the skin tissue.

Gamma ray

It has the strongest penetrating power among the three types of ionizing radiation. The wavelength is short and the energy is high. It has a very high penetrating power, so it is necessary to build a barrier of 1m or more with lead or concrete with high density as a material. As with X-rays, it is used to explore areas that cannot be penetrated by X-rays (buildings, bridges, etc.).

Neutron beam

It is one of the types of radiation in which neutrons of atoms travel like light. Since it is emitted during a nuclear reaction, it is emitted when operating a nuclear reactor or when a neutron bomb explodes.


Non-ionizing radiation (non-ionizing radiation)

Radiation that does not ionize (ionize). It does not affect the molecular structure. Non-ionizing radiation includes ultraviolet, visible, infrared, far-infrared, microwave (radar), microwave (mobile phone), microwave (TV), short wave, medium wave (radio), and long wave (power lines, home appliances).

Unit of Radioactivity

'Radioactivity' indicates how many times a radionuclide in a material undergoes decay within a unit time, and it is determined by the amount and half-life of the radionuclide contained in the material of interest. It corresponds to the intensity of the so-called generating source. As a unit of radioactivity, conventionally Ci (qui