X-rays, from the point of view of physics, is electromagnetic radiation, whose wavelength varies in the range of 0.001 to 50 nanometers.It was discovered in 1895 by German physicist V.K.Rentgenom.
By nature, these rays are related to solar ultraviolet radiation.In the spectrum of the sun's rays are the longest radio waves.Behind them is an infrared light that our eyes do not perceive, but we feel it as heat.Next come the rays from red to violet.Then - UV (A, B and C).And right behind him the X-rays and gamma rays.
X-radiation (X-rays) can be obtained in two ways: the braking in the material passing therethrough of charged particles and the transition of electrons to the higher layer when released into internal energy.
Unlike visible light, the rays have a very large length, therefore able to penetrate through the opaque material without being reflected, refracted and does not accumulate therein.
Bremsstrahlung get easier.Charged particles braking emit electromagnetic radiation.The greater the acceleration of the particles and thus sharper braking, the greater the generated x-ray radiation and its wavelength becomes smaller.In most cases in practice recourse to ray generation during deceleration of electrons in solids.This allows you to control the source of the radiation, avoiding the dangers of radiation exposure, because when disconnecting the X-ray source disappears completely.
most common source of such radiation - X-ray tube.The emitted radiation of her uniform.It is present and mild (long-wave), and hard (short-wave) radiation.Soft characterized in that it is completely absorbed by the human body, so such an X-ray radiation damage brings twice more than tough.When excessive electromagnetic irradiation in human tissues ionization can damage cells and DNA.
tube - a vacuum tube with two electrodes - a cathode and a negative anode positive.When heating of the cathode, electrons are vaporized therefrom, then they are accelerated in an electric field.Faced with a solid anode, they begin braking, which is accompanied by the emission of electromagnetic radiation.
X-ray radiation, the properties of which are widely used in medicine, based on the receipt of a shadow image of the object on the sensitive screen.If diagnosed body shine a beam of parallel rays, then the projection of shadows of this body will be transmitted without distortion (in proportion).In practice, the light source is more like a point, so it is located at a distance from man and from the screen.
To get an X-ray man is placed between the X-ray tube and the screen or film acting as radiation detectors.As a result of radiation in the picture bone and other dense tissue appear as obvious shadows look more contrast against the background less expressive areas that convey the tissue with less absorption.On X-rays a person becomes a "semi-transparent".
common, X-rays may be scattered and absorbed.Before absorbing the rays may extend hundreds of meters in the air.In dense matter, they are absorbed more quickly.Biological human tissues are heterogeneous, so the absorption of the rays depends on the density of the tissue.Bone absorbs rays faster than the soft tissues because it contains a substance having a high atomic number.The photons (individual particles of light) are absorbed by different tissues of the human body in different ways, that allows to obtain sharp images with the help of X-rays.
