Ionizing radiation

The ionizing radiation is radiation interaction with a substance which leads to the formation of ions of different signs. All types of ionizing radiation is divided into electromagnetic radiation (x-ray and gamma-radiation and corpuscular radiation, consisting of various nuclear particles. Sources of ionizing radiation are used: natural or artificial radioactive substances, x-ray machines. Ionizing radiation are formed in various nuclear reactions. In addition, ionizing radiation coming from space.
X-ray radiation occurs in the x-ray tube (see). There are short-wave and long-wave x-ray radiation. The wavelength of x-ray radiation is dependent on the voltage applied to the anode. The smaller the wavelength of x-ray radiation, the higher its energy.
From quantum mechanics known that electromagnetic radiation emitted not continuous individual portions of energy with a certain wavelength, called quanta, or photons. When passing through matter quanta x-ray radiation transfer their energy to the electrons of the atoms of the medium. As a result of interaction with the electron quantum or disappears (the phenomenon of the photoelectric effect), or reduce their energy (Compton effect). The distance traveled by light in substance, determines its penetrating ability. X - radiation penetrating radiation, i.e., radiation, which has high penetrating power.
The penetrating power of radiation depends on the energy of quanta. The radiation of low-energy quantums has low penetrating power and is called a soft, with great energy of quanta and high penetrating power - hard.
For more hard x-ray quanta low energy delay filters (often made of copper and aluminum). X-ray radiation passed through the filter, called filtered (as opposed unfiltered) .
The gamma rays produced in nuclear reactions and is emitted from the nucleus or directly at the moment of reaction, or after a certain period of time. Energy gamma rays can have different values: from tens of thousands of electron volts (Kev) to millions of electron volts (MeV). For each radioactive element characteristic inherent energy of emitted gamma-quanta.
In medicine are widely used gamma radiation artificially obtained radioactive isotopes (cobalt-60, caesium-137 and other). Physical properties of x-ray and gamma-radiation, as well as their biological effects on living organisms are the same.
To corpuscular radiation include: alpha particles, beta radiation, as well as the proton and neutron radiation. They are emitted excited nuclei of atoms, so called nuclear radiation. When passing through matter all particles (except neutrons) lose their energy in small portions on excitation and ionization of atoms and molecules. The energy necessary for formation of a single pair of ions, are small compared with the energy of the particles, so on your way particle produces a large number of ion pairs. The number of ion pairs in the unit path of a charged particle, or the density of ionization, depends on the velocity of the particle and its charge. The density of ionization along the path of a particle varies. With the reduction in the rate gradually increases the density of ionization, reaching the maximum value at the end of the race. This property is charged particles (which have no electromagnetic radiation) used in radiation therapy (see), choosing energy of the particles in such a way that their run ended in the tumor.
Ionization arising during the passage of corpuscular radiation through a medium, due not only to the primary incident on Wednesday radiation, but also those of secondary radiation, which are formed by the interaction of primary radiation with this environment. So, the neutron, uncharged particles produce ionization due to secondary protons produced in the collision of neutrons with nuclei of hydrogen. Charged particles and neutrons can also engage in nuclear reactions with nuclei of atoms in the medium. When capturing these nuclei bombarding particles are formed new unstable nucleus, which emit alpha, beta and gamma radiation, called capture. Therefore, samples or biological objects after irradiation corpuscular radiation remain radioactive until, until you break up the resulting unstable nucleus. Corpuscular radiation of high energies, i.e., radiation, consisting of particles with great speed, receive an artificial way in charged particle accelerators (see). Accelerators emit particles separate portions, or pulses. Such radiation is called the pulse.