There are three types of radiation called alpha, beta and gamma that can be separated by a magnetic field or an electric field:
alpha radiation (α): also called alpha particles or alpha rays, these are particles carried by two protons and two neutrons, and are therefore helium nuclei. They have a positive charge +2 and mass number 4.
beta radiation (β): beta rays or beta particles, they are electrons, negative particles with charge – 1 and mass number 0.
Gamma radiation (γ): or gamma rays. The wavelength of this radiation varies from 0.5? to 0.005? (unit of measure: angstrom). Gamma radiations are electromagnetic waves, and they have zero charge and mass, continuously emit heat and have the ability to ionize the air and make it conductive of electrical current.
Mind Map: Radiations
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A radioactive core emits alpha or beta radiation, and gamma radiation is always present. The beta particle can reach a speed of up to 95% of the speed of light, whereas the alpha particle is slower and reaches a speed of 20,000 km/s, and gamma rays reach the speed of electromagnetic waves (300,000 km/s).
To better understand the speed and power of alpha, beta and gamma particles in relation to matter, here are some examples of the penetration power of radiation:
- Despite being quite energetic, alpha particles are easily blocked by a sheet of paper;
- Beta particles are more penetrating and less energetic than alpha particles, they can cross laminae of lead up to 2 mm or aluminum up to 5 mm in air, but are barred by a wooden board 2.5 cm thick;
- Gamma particles travel thousands of meters in the air, are more dangerous, when emitted for a long time can cause malformation in cells. Gamma rays can pass through steel plates up to 15 cm thick, but are blocked by thick lead plates or concrete walls.
We can conclude that alpha particles have a mass and electrical charge relatively higher than the others, however, they are easily blocked by a sheet of paper. Gamma radiation, on the other hand, is not as energetic, but it is extremely penetrating, it can pass through the human body, it is only held by a thick concrete wall or by some type of metal.
* Mind Map by Victor Ricardo Ferreira
Chemistry Teacher
By Líria Alves
Graduated in Chemistry
Source: Brazil School - https://brasilescola.uol.com.br/quimica/radiacoes-alfa-beta-gama.htm
