Physics of the radioactivity and measurement of radioactive radiation

Radioactivity is the property of a number of atomic nuclei to transform spontaneously, without external influence, into another atomic nuclei. When this happens, energy in the form of kinetic energy and electromagnetic radiation is released. Radioactive atoms were produced at the time of creation of the world. Only the extremely long-lived radioactive elements such as uranium and thorium have remained. The aim of this contribution is to give a short introduction to the physics of radioactivity and the measurement of radioctive radiation. Since complicated mathematical terms will be dispensed with, it is necessary to present some relationships in extremely simplified form