Nuclear radiation is a phenomenon in which energy is released from the nucleus of an atom in the form of a stream of microscopic particles.
It occurs when the nucleus of an atom changes from one structure or energy state to another. Nuclear radiation exists in all matter, is the objective fact of existence for billions of years, is a normal phenomenon.
Nuclear radiation can be divided into direct ionizing radiation and indirect ionizing radiation. Direct ionizing radiation includes charged particles such as protons, while indirect ionizing radiation includes photons, neutrons and so on. Nuclear radiation can cause ionization or excitation of substances, so it is called ionizing radiation.
Most of the substances with nuclear radiation are some isotopes, such as phosphorus, cesium, iodine, cobalt, etc., and some metals, such as uranium, thorium, plutonium, radium and so on. These substances release nuclear radiation under specific conditions.
Discovery of Nuclear Radiation:
As early as 1783, French physicists Marie Curie and her wife discovered some new substances, polonium (Ir) and radium (Ra), while studying uranium ore, and found that these new substances were radioactive. In the following decades, people gradually discovered the existence and application of nuclear radiation through the study of nuclear reactions and the exploration of radioactive substances.
In the early 20th century, scientists studying nuclear reactions discovered that when an alpha particle is used to hit a uranium-235 nucleus, fission occurs, releasing a large amount of heat energy and neutrons moving at high speeds. These neutrons further caused other uranium nuclei to undergo fission, forming a chain reaction, which is the famous chain reaction. This discovery provided the basis for the application of nuclear energy.
With the advancement of science and technology and the development of related technologies, the application of nuclear radiation has become more and more extensive, such as for medical imaging, military security checks and so on. At the same time, nuclear radiation also faces many safety and ethical issues, such as the development and use of nuclear weapons and the safe management of nuclear power plants. Therefore, relevant regulations and supervision must be strengthened to ensure the safety of people's lives and the stability of the environment.
Reference for the above: Baidu Encyclopedia-Nuclear Radiation