A radioactive disintegration. Kinds of radioactive radiation

The radioactive disintegration is property of nucleuses of the certain elements spontaneously (i.e. without any external influences) to transform into nucleus of other elements with emission of the special radiation, which is named by radioactive radiation. This phenomenon is named radioactive disintegration. Radioactive disintegration is accompanied by small allocation of heat. The radioactive phenomenon happening at natural isotopes, meeting in the nature, is named a natural radioactive disintegration, and disintegration happening in is artificial isotopes - an artificial radioactive disintegration. Radioactive isotopes are formed in nuclear reactors. Devices registering α, and β -particles, x-ray and neutrons, protons are called detectors of ionizing radiation.

We have three kinds of radioactive radiations - α, β, γ, various by the nature, but having some general properties. The general name is radioactive radiation.

The alpha-radiation is a stream α-particles with high kinetic energy, which is represented with nucleuses of helium. The alpha particle consists of two protons and two neutrons also it is designated .

Beta-radiation is a stream of β-particles with high kinetic energy, which represent or electrons (at the majority of radioactive elements), or positrons (at the some artificial isotopes).

Beta - particle is designated β^- or (electron) and β⁺ or (positron).

The γ - radiation has the electromagnetic nature and represents a stream of photons with very high energy and has small wave length (0,1 nanometers and less).

Characteristics of radioactive radiation are the mass and a charge of particles, their speed of movement and kinetic energy corresponding for speed and also distribution of particles by energy, which is named a spectrum of radioactive radiation. Particles only one kind, α or β, are radiated from nucleus of the given substance out in the one act of disintegration. Accordingly distinguish three basic kinds of disintegration of radioactive nucleuses: α- disintegration, β-electronic and β-positron’s. Any of these disintegrations can be accompanied by radiation γ - photons. Against γ - radiations can be applied to protection thick layers the grounds, concrete, a brick.

α-disintegration. The formula of disintegration

For nucleuses of heavy elements it is characteristic α-disintegration, thus the general quantity of nucleons in nucleus decreases, and it becomes more stability. The alpha - disintegration is described by the equation:

If α-particles way out from nucleus, then the charge of a nucleus and accordingly atomic number of an element decreases on two units, and mass number - for four units. Some α-particles can overcome action of nuclear forces and come off a nucleus, under certain conditions. This process is named tunnel effect.

β-disintegration. The formula of disintegration

Beta-disintegration happens in nucleuses, which instability because nucleuses have different quantity of neutrons and protons. If there is a lot off neutrons in a nucleus, then electronic β-disintegration happens, and one neutron transforms to proton, thus is born electron in a nucleus:

It is thrown out and a nucleus has more stability complex of nucleons. Electronic - β^- - disintegration is described by the equation:

Thus the charge of a kernel and accordingly atomic number of element increase for unit, and its mass number remains without changes.

Electronic β-disintegration is characteristic for many natural and is artificial the received radioactive isotopes, for example, disintegration of isotope potassium with its transformation into calcium:

One proton transforms to a neutron, and the positron is born in a nucleus at positron β-disintegration:

It is thrown out and a nucleus has more stability complex of nucleons. Positron β-disintegration is described by the equation:

The charge of a nucleus and accordingly atomic number of an element decreases for unit, and the mass number remains without change.

Beta - radiation of the same elements contains particles with various energy within the limits of from the smallest up to some maximal size. Therefore a spectrum β- radiations continuous. The scientist Pauli to explain difference in energy β-particles at disintegration of nucleus of the same elements. Century in 1931 Pauli has assumed, that neutral particles way out from a nucleus together with β- particles at β-disintegration. This particles have very small mass and energy, which have some significant. The sum of this energy with energy of β-particles is constant significant ε_o. In the further these particles have been found out experimentally. The particle is radiated together with a positron, has been named neutrino ν. The equations of mutual transformation of nucleons look like:

Transformation of a proton into a neutron can happen as by capture by a nucleus of one of electron from the K atomic level

This phenomenon is named to as electronic capture or К-capture, for example, transformation of an isotope Be in Li (lithium):

Spontaneous disintegration of nucleuses of heavy elements is radioactive disintegration also, for example, isotopes of uranium disintegrate on two splinters, relatives among themselves under atomic number and mass number.

The some elements have chain of such consecutive disintegrations, last disintegration create stability element. Set of the elements, forming a similar chain, is named radioactive family, or radioactive line.

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