What Is Natural Radioactivity?

Natural radioactivity (Natural radioactivity) refers to the properties of naturally occurring radioisotopes that can spontaneously emit rays (such as alpha rays, beta rays, gamma rays, etc.) from unstable atomic nuclei and decay to form stable elements.

Natural radioactivity (Natural radioactivity) refers to the properties of naturally occurring radioisotopes that can spontaneously emit rays (such as alpha rays, beta rays, gamma rays, etc.) from unstable atomic nuclei and decay to form stable elements.

Chinese name

Natural radioactivity

Presenter

Becquerel

Presentation time

1896

Attributes

Naturally occurring radioisotopes

Produce

Produced by the transition of outer electrons to inner ones

Natural Radioactive History

In 1896, French physicist Henry Becquerel discovered that uranium salts or metallic uranium could sensitize nearby photographic negatives wrapped in black paper while studying phosphorescent materials, and concluded that uranium could automatically emit a certain kind of light continuously. Invisible, quite penetrating rays.

At first it was thought that this radiation was similar to the X-rays just discovered. But research by physicists has shown that this radiation is more complicated than X-rays. Rutherford first discovered that its decay methods followed an exponential decay, that is, there was a half-life. Rutherford and his student Frederick Sody were the first to discover that many decays can cause nuclear transmutation and turn an atom into another atom.

According to the results of existing research, we already know that all elements with an atomic number above 84 have natural radioactivity, and certain elements such as carbon and potassium also have this property.

Natural radioactive type

Radioactive nuclear energy decays in many different forms to bring itself to a more stable state. According to the types of nuclear radiation particles, the radioactivity is divided into the following types:

Alpha activity: An alpha particle (He) is emitted from the nucleus. Alpha ray ionization effect is large, and the penetration ability is small;

radioactivity: -ray is a high-speed electron flow. According to the nature of the electrons emitted by the nucleus, decay can be divided into decay and decay. Beta decay refers to the type of decay in which a positron (e) and an electric neutrino are emitted from the nucleus; beta decay refers to the type of decay in which an electron (e) and an anti-electric neutrino are emitted from the nucleus. At the same time, the nucleus can also absorb an orbiting electron and emit neutrinos, which is called the orbiting electron capture process. -ray ionization is small, and the penetration ability is large;

Gamma radiation: Gamma rays are electromagnetic waves with very short wavelengths. Gamma radioactivity is often accompanied by alpha or beta decay. Alpha or beta decaying nuclei are generally in an excited state and need to transition to the ground state by releasing gamma rays, that is, to produce gamma radioactivity. The charge and mass numbers of the daughter and mother nuclei of the transition are the same, but the internal states of the nuclei are different. -rays have a small ionization effect and a large penetration ability.

In addition to the three main types of radioactivity mentioned above, some nuclei also have other particle radioactivity such as protons and neutrons.

Natural radioactive origin

The naturally occurring radionuclide on Earth is the residue of an explosion during the synthesis of a supernova nucleus. These nuclides have a long half-life and remain in the nebula during star accretion until now. The short-lived radionuclides are the decay of these original nuclides. Cosmic ray nuclides also cause small amounts of radionuclides in nature.