X-ray radiation, from the point of view of physics, is electromagnetic radiation, the wavelength of which varies in the range from 0.001 to 50 nanometers. It was discovered in 1895 by the German physicist V.K. Roentgen.
By nature, these rays are related to solar ultraviolet. In the spectrum of the sun's beam, the longest are radio waves. Behind them comes infrared light, which our eyes do not perceive, but we feel it as heat. Next come the rays from red to purple. Then - ultraviolet (A, B and C). And immediately after it are x-rays and gamma radiation.
X - ray radiation (X-rays) can be obtained in two ways: when the charged particles passing through it are decelerated in a substance and when electrons transfer from higher layers to internal ones when energy is released.
Unlike visible light, these rays have a very large length, therefore they are able to penetrate through opaque materials without being reflected, without refracting and not accumulating in them.
Brake radiation is easier to obtain. Charged particles during braking emit electromagnetic radiation. The greater the acceleration of these particles and, therefore, sharper braking, the more x-ray radiation is formed, and its wavelength becomes smaller. In most cases, in practice they resort to the generation of rays during the braking of electrons in solids. This allows you to control the source of this radiation, avoiding the danger of radiation exposure, because when you turn off the source, the x-ray radiation completely disappears.
The most common source of such radiation is an x-ray tube. The radiation emitted by it is inhomogeneous. It contains both soft (long-wave) and hard (short-wave) radiation. Soft is characterized by the fact that it is completely absorbed by the human body, therefore, such x-ray radiation brings harm twice as much as hard. With excessive electromagnetic radiation in the tissues of the human body, ionization can lead to damage to cells and DNA.
A tube is an electrovacuum device with two electrodes - a negative cathode and a positive anode. When a cathode is heated, electrons evaporate from it, then they are accelerated in an electric field. Faced with the solid matter of the anodes, they begin braking, which is accompanied by the emission of electromagnetic radiation.
X-ray radiation, the properties of which are widely used in medicine, is based on obtaining a shadow image of the studied object on a sensitive screen. If the diagnosed organ is exposed through a beam of rays parallel to each other, then the projection of the shadows from this organ will be transmitted without distortion (proportionally). In practice, the radiation source is more like a point source, so it is placed at a distance from a person and from the screen.
To get an x-ray, a person is placed between the x-ray tube and the screen or film acting as radiation detectors. As a result of irradiation in the image, bone and other dense tissues appear in the form of clear shadows, look more contrasted with less expressive areas that transmit tissues with less absorption. In x-rays, a person becomes "translucent."
By spreading, x-rays can be scattered and absorbed. Before absorption, rays can travel hundreds of meters in the air. In a dense substance they are absorbed much faster. Human biological tissues are heterogeneous, therefore the absorption of rays by them depends on the density of the tissue of organs. Bone tissue absorbs rays faster than soft tissue, because it contains substances with large atomic numbers. Photons (individual particles of rays) are absorbed by different tissues of the human body in different ways, which makes it possible to obtain a contrast image using x-rays.