Polonium 210: half-life. Why is polonium 210 used?

Polonium-210 causes a very clear association with radiation. And this is not in vain, because it is extremely dangerous.

History of the discovery

His existence was predicted back in 1889 by Mendeleev, when he created his famous periodic table. In practice, this element under number 84 was obtained nine years later by the efforts of the Curie couple, who studied the phenomenon of radiation. Maria Sklodowska-Curie tried to find out the cause of strong radiation emanating from some minerals, and therefore began working with several rock samples, processing them in all available ways, dividing into fractions and discarding unnecessary ones. As a result, she received a new substance, which became an analog of bismuth and the third open radioactive element after uranium and thorium.

Despite the successful results of the experiment, Maria was not in a hurry to talk about her findings. Spectral analysis, conducted by a colleague of the Curie couple, also gave no grounds for talking about the discovery of a new element. Nevertheless, in a report at the meeting of the Paris Academy of Sciences in July 1898, the spouses reported on the alleged receipt of a substance exhibiting the properties of the metal and suggested calling it polonium in honor of Poland, the motherland of Mary. This was the first and only in the history of the case, when an element that had not yet been identified was already named. Well, the first sample appeared only in 1910.

Physical and chemical properties

Polonium is a relatively soft silver-white metal. It is so radioactive that it glows in the dark and constantly heats up. At the same time, its melting point is slightly higher than that of tin - only 254 degrees Celsius. The metal oxidizes very quickly in the air. At low temperatures it forms a monatomic simple cubic crystal lattice.

According to its chemical properties, polonium is very close to its analogue - tellurium. In addition, the high level of radiation has a great influence on the nature of its compounds. So the reactions involving polonium can be very spectacular and interesting, albeit quite dangerous from the point of view of the health benefits.

Isotopes

In total, science currently knows 27 (according to other sources - 33) forms of polonium. None of them is stable, and they are all radioactive. The heaviest of the isotopes (with ordinal numbers from 210 to 218) are found in small numbers in nature, the rest can only be obtained by artificial routes.

Radioactive polonium-210 is the longest living of natural forms. It is contained in a small amount in radium-uranium ores and is formed by a chain of reactions starting with U-238 and lasting approximately 4.5 billion years, if we talk about the half-life.

Receiving

In 1 ton of uranium ore there is an isotope of polonium-210 in an amount equal to approximately 100 micrograms. They can be identified in the processing of industrial waste, but to obtain a more or less significant volume of the element would have to handle a huge amount of material. A much simpler and more effective method is synthesis by irradiating neutrons of natural bismuth in nuclear reactors.

As a result, after some other procedures, polonium-210 is obtained. Isotopes 208 and 209 can also be obtained by irradiating bismuth or lead with accelerated beams of alpha particles, protons, or deuterons.

Radioactivity

Polonium-210, like other isotopes, is alpha emitters. The heavier group also emits gamma rays. Despite the fact that isotope 210 is the source of only alpha particles, it is quite dangerous, it can not be taken by hand and even close to a close distance, because when heated, it becomes aerosolized. It is also extremely dangerous to get polonium inside with breathing or food. That's why the work with this substance takes place in special sealed boxes. Curiously, this element was found about a half a century ago in tobacco leaves. The decay period of polonium-210 compared to other isotopes is quite large, and therefore it can accumulate in the plant and subsequently harm the health of the smoker even more. Nevertheless, any attempts to extract this substance from tobacco were unsuccessful.

Danger

Since polonium-210 emits only alpha particles, observing certain precautions, one should not be afraid of working with it. The range of these waves rarely exceeds a dozen centimeters, in addition, they usually can not penetrate the skin.

However, once inside the body, they do him great harm. When it gets into the blood, it quickly spreads across all tissues - in a few minutes its presence can be seen in all organs. First of all, it is present in the kidneys and liver, but in general it is distributed fairly evenly, which explains its high overall damaging effect.

The toxicity of polonium is so great that even small doses cause chronic radiation sickness and death in 6-11 months. The main ways of excretion from the body are through the kidneys and the digestive tract. Dependence on the method of hit is observed. The half-life is 30 to 50 days.

Accidental poisoning by polonium is completely impossible. To obtain a sufficient amount of the substance, it is necessary to have access to the nuclear reactor and deliberately lay the isotope to the victim. The complexity of the diagnosis is also that only a few cases have been known in the history. The first victim is the daughter of the discoverers of polonium - Iren Joliot-Curie, who during the research broke the capsule with the substance in the laboratory and died after 10 years. Two more cases fall to the 21st century. The first of them is the sensational case of Litvinenko, who died in 2006, and the second - the death of Yasser Arafat, in the things of which traces of the radioactive isotope were found. Nevertheless, the final diagnosis was never confirmed.

Disintegration

One of the longest-lived isotopes, along with 208 and 209, is polonium-210. The half-life (that is, the time for which the amount of radioactive particles is reduced by half) in the first two is 2.9 and 102 years, respectively, and for the last 138 days and 9 hours. As for the other isotopes, their lifetime is calculated mainly by minutes and hours.

The combination of various properties of polonium-210 makes it the most convenient of a number for use in various spheres of life. Being in a special metal shell, he can no longer harm his health, but is able to give his energy for the benefit of mankind. So, what is polonium-210 used for today?

Modern application

According to some reports, about 95% of polonium production is concentrated in Russia, with about 100 grams of substance synthesized per year, and almost all of it is exported to the United States.

There are several areas in which polonium-210 is used. First of all, these are space vehicles. With its compact dimensions, it is indispensable as an excellent source of energy and heat. Despite the fact that approximately every 5 months its effectiveness is reduced by half, heavier isotopes are much more expensive in production.

In addition, polonium is absolutely indispensable in nuclear physics. It is widely used in the study of the effect of alpha radiation on other substances.

Finally, another area of application is the manufacture of devices for the removal of static electricity for both industry and home use. It is even surprising how such a dangerous element can become almost a kitchen utensil, being encased in a secure shell.