γ, also known as γ particle flow, is the atomic nucleus energy level leap metamorphosis when the release of rays, is the wavelength shorter than 0.01 ? electromagnetic waves. γ rays have a strong penetrating power, the industry can be used to detect injuries or the automatic control of the assembly line. γ rays of the cell has a killing effect, medical treatment is used to treat tumors.
Principle
Radioactive nuclei in the occurrence of α-decay, β-decay produced by the new nucleus tends to be in the high-energy level, to the low energy level leap, radiated γ photons. Atomic nuclear decay and nuclear reactions can produce γ rays. Its wavelength is shorter than 0.2 ? electromagnetic waves[2] . γ-ray wavelength is shorter than X-rays, so γ-rays have a stronger penetrating ability than X-rays.
Gamma rays are electromagnetic photons with a frequency higher than 1.5 gigahertz. Gamma rays do not have electric charge and static mass, so they have a weaker ionization ability than alpha particles and beta particles. Gamma rays are extremely penetrating and have high energy. Gamma rays can be stopped by nuclei with high atomic numbers, such as lead or spent uranium.
Basic effects
When gamma rays pass through matter and interact with atoms, they produce three effects: the photoelectric effect, the Compton effect, and the positron-negative electron pair.
Measurement method
γ photon is not charged, so it can not be measured by the magnetic deflection method of its energy, usually caused by the use of γ photons of the above secondary effects indirectly, such as through the measurement of photoelectrons or positron-negative electron pairs of energy deduced. In addition, the energy of γ photons can be measured directly by γ spectrometer (using the diffraction of γ rays by crystals).
Scintillation counters consisting of fluorescent crystals, photomultiplier tubes and electronics are commonly used to detect the intensity of γ-rays.
Effects on the human body
Gamma rays have a strong penetrating ability. When the human body is irradiated by γ-rays, γ-rays can enter the body's internal and ionization of cells with the body, ionization of ions can erode complex organic molecules, such as proteins, nucleic acids and enzymes, which constitute the main components of the living cell tissues, and once they have been destroyed, will lead to the normal chemical processes within the body to be interfered with, and seriously can make the cell death.