Radioactivity is a spontaneous process in which the nucleus, emitting one or more particles or quantum of electromagnetic radiation, transforms into another nucleus. Radioactive pollution is the increased amount of radioactive substances and radiation in life in the middle. It can accumulate in the water, air, soil, and that way radioactive pollution can arrive through food to man.
Initially, the nature of radiation was not known; there was a word about radiation, so “the collapse” of the core was called radioactivity, and nuclei that emit particles and radiation were called radioactive isotopes or nuclei. The initial collapse of the core, which is called the parent nucleus, formed a new core, a descendant, who can have a serial number Z and mass number A which vary from the parent nucleus.
Radioactive decay is characterized by the type and energy of radiation emitted and the time of half-life. Alpha, beta, and gamma decay and spontaneous fission occur in nature. During alpha decay, nuclei emit helium atoms 4He. During the beta decay, nuclei emit an electron and an antineutrino. During the disintegration of the gamma nucleus, electromagnetic waves (photons) of high energy are emitted.
The characteristics of Radioactive decay are:
- not a chemical reaction;
- changes occur with the release of huge amounts of energy (MeV);
- flows spontaneously or it can not be affected;
- the core that collapses is called the parental core, and the stable core that forms after the collapse of the parental core is called a descendant.
History of the discovery of radioactivity
Natural radioactivity was discovered at the end of the last century by French physicist Becquerel. Trying to determine the cause of the fluorescence and phosphorescence of some materials, Becquerel wrapped a photographic plate in black paper and placed it in crystals of uranium salts, and then exposed it all to sunlight.
After developing photographic plates, he shows that the plate was “illuminated,” therefore, the uranium emitted radiation that can pass through black paper and act on the plate. Becquerel thought that uranium salts emit radiation under the influence of sunlight. However, one day, due to cloudiness, he laid the experiment off, and he put the imaging plate wrapped in black paper away, with uranium salts over it. After several days, however, he developed the plate, and to his great surprise, he found that it was very irradiated.
Becquerel correctly concluded that the uranium salts, without outside interference, spontaneously emit radiation that passes through the paper and causes the blackening of the imaging plate.
Curie named this phenomenon: radioactivity. Marie Curie, along with Pierre Curie, studied radioactivity and other uranium compounds, such as pebbled ores (mainly uranium oxide U3O8). Curie found that radiation is much stronger than anything that they have ever seen, which is not proportional to uranium. She assumed that pebbled ores contain a small amount of an element that radiates much more. Using ordinary chemical procedures for the element separation. Curie couple successfully isolated polonium and radium. Radium was isolated after long and patient processing of one ton of pebbled ores that had already had uranium extracted from them. First, small amounts of radium, in the form of radium chloride. Pure radium was obtained in 1910 by electrolysis.
Radiation illness or radiation syndrome is a cluster of signs and symptoms that occur:
-in the acute form, the six weeks after the radiation greater than 0.7 Gy (absorbed radiation),
-in a short time, a few hours to 1-2 days
-in the chronic form, the cumulative effect of small doses on two or more radiosensitive tissues in a significant period (less than five years), both external or internal radiation.
Death after radiation occurs even without the development of disease syndromes if the radiation dose was over 10,000 rem because the radiation immediately damages the central nervous system, breathing, circulation, etc.
Based on the manner of formation, radiation illness can be accidental (occurring during the production, use, research, treatment, or handling of the radioactive material) or intentional (after the usage of radioactive weapons in war or terrorist activities).
Based on the severity and consequences to the health of exposed people the disease is divided into acute and chronic.
Negative effects of radiation:
• Eye damage
• Cancer of the skin and other organs
• Leukemia (tumor of blood cells and bone marrow)
• Damage to genetic material mutations
Every resident of the country is exposed to natural or “background” radiation and annually receives a small amount of radiation (excluding medical examinations and radiation therapies). People are occupationally exposed to radiation, X-rays, invasive diagnosticians, employees in nuclear power plants. Radiation can accumulate daily in the body, but the body can regenerate, so daily exposure to this type of radiation is not dangerous. But, when the body is exposed to a high dose of radiation in a short period, the regeneration process can not repair the damage and causes radiation illness.
|Radiation source||The half-life||Food type||The location and type of activity|
|53 days||Milk, dairy products, leafy vegetables||Bones, leukemia|
|Iodine 131||8 days||Milk from cows grazing, leafy vegetables||The thyroid gland, tissue radiating|
|Cesium 137||30 years||Milk, dairy products, leafy vegetables, meat, fish||Bones and other types of cancer|
|Phosphorus 32||14 days||Fish, leafy vegetables||Bone and liver|
|Aquatic fauna||Bone and liver, a highly carcinogenic effect|
Radiation protection can be spatial, temporal, and insulating. The shorter the time spent at the radiation site. Stay as far away from the source as possible from radiation. Protective barrier – clothes, layers of earth, concrete, lead.
Radiation control and protection
Understandably, a person cannot get rid of the impact of radiation, especially those that come from nature. However, for people who are occupationally exposed to lower or higher doses of radiation, there are precautions to minimize the risk of negative consequences.
Radiation protection is accomplished in two basic forms:
– Protection against radiation
– Protection against radioactive contamination.
Protection against external radiation is, in principle, carried out by decreasing the dose of radiation to a minimum. It can be achieved by:
- weather protection
- remote protection
- protection through the absorber.
Protection against radioactive contamination considers taking appropriate measures so the radioactive substances would not come into direct contact with living organisms and would not penetrate the surrounding environment. Since man is unable to register the radiation, it is necessary that when working with radioactive materials, regular environmental control measures (monitoring system) should be introduced. Measures of the absorbed dose in individuals exposed to radiation should also be measured.
The simplest device for detecting radioactivity is a badge with a photographic film worn by people who work with radioactive material. If radiation reaches the badge, it begins to fog.
It is possible to detect the produced radionuclides in the environment, which are a consequence of the nuclear accident in Chernobyl. Sadly it still is detected today, but the concentrations are negligible and do not affect humans and the environment. Potential polluters of the environment with radioactive substances are nuclear power plants. The technological processes in which there is an increase in the concentration of natural radionuclides are also polluters. Therefore, it is necessary to perform systematic monitoring of radioactivity so that we would be able to protect the environment and enable a timely response in the event of an increase in radioactivity.
It is probably the best-known method of measuring radioactivity Geiger counter, a tube filled with argon in which find two electrodes. When radiation enters through a thin window, ionizes argon atoms by erupting electrons that then conduct current moving towards the positive charged central electrode. The current is a registered amplifier, which is accompanied by the appearance of a warning sound.