Rays

The classification of different types of radiation are carried out between 1898 and 1902.Ernest Rutherford, then a young research student at the Cavendish Laboratory, identified two types of "rays" radioactive designated with the Greek letters alpha and beta.The scheme was due, among other properties, the penetrating ability of radiation in matter, being the alpha radiation much less penetrating than beta. In the middle of 1902 added a third type, even sharper than losanteriores, he called gamma. Today we know that alpha radiation is the emission of helium nuclei (two protons and two neutrons) from an unstable atomic nucleus, beta radiation are electrons emitted in the decay process beta and gamma rays are high-energy photons.
• Alpha particles emitted by natural radionuclides are not able to pass through a sheet of paper or human skin and slow down a few centimeters of air. However, if an alpha emitter is inhaled (eg, the 210Po), ingested or enters the body through the blood (eg wound) can be very harmful.
• Beta particles are electrons. The lower energy are detenidoss through the skin, but most of those present in natural radiation can penetrate. Like alpha emitters, if a beta emitter enters the body can cause serious damage.
• Gamma rays are the most pervasive types of radiation described. Gamma radiation frequently accompanies and sometimes beta to alpha. Gamma rays pass easily through skin and other organic substances, so it can cause serious damage to internal organs.X-rays (*) fall into this category are also photons, but with a lower penetration capacity than gamma.

The different types of radiation and their penetrating power.A radiation types classified by Rutherford, must be added the neutron radiation, which appears in nature in the process of spontaneous fission. Neutrons are more capable of penetrating gamma-rays, and can only stop a thick concrete barrier, water or paraffin (hydrogen-rich compounds).(*) While this is the same type of radiation, the nomenclature remains gamma and X due to the cause that produces it, while gamma rays are nuclear (restructuring of the atomic nucleus), x-rays have their origin in the restructuring of the atomic electrons in the crust.