Alpha Decay

Alpha Decay

Alpha Decay with suitable examples and sketches are discuss here advanced. Alpha Decay is needed to read as engineer student.

What is radiation emitted by radioactive nuclei? Almost immediately, scientists found that this radiation is heterogeneous in composition. In 1899, the prominent French physicist Henri Becquerel and a number of other scientists showed that under the influence of a magnet part of the radiation deviates, while the other propagates in a straight line

 experiment on radiation deflection
experiment on radiation deflection

Diagram of the experiment on radiation deflection, where K is a lead container, P is a radioactive preparation, F is a photographic plate, and B is a magnetic field.

In addition, it was found that rays deflecting in a magnetic field are divided into two streams in an electric field, i.e. are positively and negatively charged particles. The English physicist Ernest Rutherford called the first type of radiation “alpha-rays”, and the second “beta-rays.” Radiation not deviating in a magnetic field was soon called “gamma rays.” A little later it turned out that gamma rays are similar to ordinary light, but their energy is much greater than the energy of light radiation. In 1900, Rutherford established that beta rays are simply a stream of electrons (e–); in 1906, he also showed that alpha rays are a stream of helium nuclei (42He) without electron shells.

In 1902-1907, the existence of radioactive series was discovered, i.e. sequences of natural radioactive isotopes: each subsequent isotope is formed from the previous one by decay with the emission of an alpha or beta particle. Consider the types of radioactive decay. The affiliation of radioactive decay to one form or another is related to the type of emitted particles. Alpha decay is possible for heavy nuclei with a sufficiently large charge Z> 60 (i.e., after neodymium Nd). In α decay, one element turns into another with a charge less by 2; in this case, the mass number of the nucleus decreases by 4. During the transformation, an α-particle (4He nucleus) flies out of the nucleus, which before decay was part of the nucleus.

Alpha Decay

Alpha Decay radioactivity types
Alpha Decay

Consider an example: during alpha decay of a nucleus, an element nucleus is formed with a charge less than 2 (92 – 2 = 90) and a mass less than 4 (238 – 4 = 234). In other words, we obtain a thorium isotope with a charge of 90 and a mass number of 234:

Other decay schemes can be written similarly. Note that the sum of the mass numbers A (superscript) on the left and right, as well as the charge numbers Z (subscript) on the left and right are the same. This rule is always satisfied and is directly related to the laws of conservation of energy and charge. Alpha radiation emitted by nuclei during alpha decay is the most dangerous type of radiation in the event that α-emitting nuclei get into living organisms.

External α-irradiation, on the contrary, is the safest – you can protect yourself from it with a sheet of paper that completely retains the α-particles. Beta decay is accompanied by the release of beta particles from the nucleus (which are a stream of electrons, less often – positrons). β-decay occurs due to the fact that in unstable nuclides protons and neutrons can be converted into each other in order to compensate for the excessive excess or deficiency of neutrons. If the neutron turns into a proton p, the β-particle is emitted , which, in fact, is the free electron e–, and the antineutrino ν:

Alpha Decay with suitable examples and sketches are discuss here advanced. Alpha Decay is needed to read as engineer student.

Reference

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