γ – gamma
Radiation is divided into electromagnetic (photonic) and corpuscular one. Corpuscular radiation includes alpha particles, beta particles, protons, neutrons, etc. Photon radiation includes gamma rays and X-rays.
Gamma radiation is a short-wave electromagnetic radiation whose properties are similar to X-ray but with much higher energy and speed (approximately equal to the speed of light).
Gamma radiation sources are:
- cosmic rays;
- natural radiation sources (radioactive ores and minerals containing uranium, thorium, actinouranium; other long-lived radionuclides that are not included into natural radioactive series such as potassium (40К), rubidium (87Rb), gadolinium (152Gd), hafnium (174Hf);
- artificial radiation sources (nuclear power plants, accelerators, etc.).
Gamma rays have the highest penetrating power among all radiation types. Accordingly, protection against them is the most complicated.
What is the hazard of gamma-radiation?
Natural gamma radiation does not cause any harm to human health since it is minimum. Artificial sources are quite different.
Due to extremely high penetrating power, gamma rays easily penetrate into living cells causing their damage. Interaction with body cells causes sharp excitation of atoms and their ionization resulting in changes in the structure of molecules and various pathologies and diseases.
The most vulnerable to gamma rays are cells of hematological system, digestive tract, lymph glands, reproductive organs and hair follicles.
What is the application area of gamma radiation?
Gamma radiation is used for sterilization of certain products, medical instruments and equipment. Gamma rays determine the depth of the wells and the underlying soils in geology are established (γ-logging). In addition, gamma radiation is used in science, technology, energy, medicine, etc.
How to protect yourself from exposure?
The classical methods of protection by time, quantity and distance will help to protect personnel against exposure by artificial sources. This means that working hours in hazardous places should be limited. Besides, protective materials such as lead, concrete, lead glass, steel, depleted uranium, etc. should be used, if necessary. Individual protection means, manipulators, remote instruments will be also needed.
The best barrier against gamma rays is lead; its use is limited by low melting point anyway. Therefore, tungsten, tantalum and iron are most often used in hot spots.
As for protection of the public, people should first pay attention to suspicious items marked “radiation hazard”. In revealing such objects, do not touch them, move as soon as possible to the maximum possible distance, and immediately notify the law enforcement authorities. Hazardous finds are mostly revealed in the places of scrap metal accumulation, landfills, dumps and abandoned military facilities.
In case of radiation accident initiation, the most efficient protection against external gamma radiation will be special shelters; and in their absence, these can be basements of houses. The thicker are the walls, the more secure is the shelter. Basement of a multi-story building can decrease radiation impact by 1000.
Uatom.org Editorial Board