Geiger counter and other devices for measuring the level of radiation

Devices, whose task is to measure the level of radiation, in our time can be attributed almost to the category of consumer electronics. How does this technique work and why has it become so popular?

How it works?

The most famous and popular device for measuring radioactivity is the counter of a geiger. He owed his name and appearance to the German physicist Hans Geiger, who designed this device in 1908 together with another well-known scientist, Ernst Rutherford. Twenty years later Geiger returned to his invention and finalized it together with physicist W. Muller. Despite the fact that this device is more than a hundred years old, it has been successfully used in our days. Most household dosimeters have a similar operating principle.

How does the Geiger counter work? Its main element is a sealed glass or metal cylinder filled with a mixture of inert gases - neon and argon. Here, two electrodes are placed in a balloon. As is known, radiation is propagated in the form of wave particles. When at least one of these particles enters the meter, the gas mixture is ionized: the atoms of the gas receive an energy charge at which they can shine. This process is also fixed by the counter. To register the exact amount of radioactive particles, the ionization process is artificially extinguished. This happens within a fraction of a second. When detecting radioactive particles, the counter of the geiger produces a characteristic snapping sound.

The level of radiation is measured in other ways. Along with the gauger counters, scintillation crystals are often used. The action of these devices is based on the fact that some substances (for example, sodium iodide or zinc sulphide) glow when radioactive radiation is detected. The number of flashes depends on the dose of radiation and is fixed by a special device - a photoelectric multiplier.

Another option is the chemical method of detecting radioactivity. Here, chemical reactions occur in some substances under the action of radioactive radiation. For example, chloroform decomposes in this case and forms hydrochloric acid, which enters into a color reaction with a dye added to the chloroform.

Where do they measure radiation in everyday life?

Why do we need this technique for people who have nothing to do with a peaceful atom? Most often the dosimeter of radioactivity is used to measure the level of radiation in food or building materials. Radioactivity can also be checked by the land on which the house is built or planned to be built. It so happened that for a long time humanity was disdainful about radiation, arranging nuclear burial grounds in the most unexpected places - on the seabed or in some abandoned mine. The Chernobyl disaster made many look at radiation with different eyes. And the recent accident at Fukushima made the Geiger counter and other dosimeters popular.

As a rule, dosimeters for household use are small in size. They are equipped with displays on which you can see the level of radiation. Dosimeters can be threshold and zero-threshold. Devices of the first type operate when the permissible level of radiation is exceeded, which is set by the manufacturer beforehand. This produces a sound signal. Such dosimeters are cheaper and easier to use. Devices of the second type show a specific level of radiation, the threshold level on them can be set manually. Such a device is more convenient for professionals, when a person knows exactly what level of radiation in this case is dangerous.

As we see, it is quite possible to detect radiation in domestic conditions. But the presence of a dosimeter in the house does not yet make you a professional. Therefore, if you find infected objects or places to use the help of specialists still have to.