Half-life: the expected time for the number of radionuclides to decay to half of the original number.

Radioactivity: a physical quantity representing the characteristics of radionuclides, and the expected spontaneous nuclear transformation number of a certain amount of radionuclides in a specific energy state per unit time. A=dN/dt .

Emissivity: the ratio of emittance N 1 precipitated from rocks or ores in a certain time interval to total emittance N2 generated by decay in the same time interval, that is, η*= N 1/N2× 100%.

Ground state of nucleus: the nucleus in the lowest energy state, and the energy state of this nucleus is called ground state.

Nuclear decay: the phenomenon that the nucleus of a radionuclide spontaneously changes from the nucleus of one radionuclide to the nucleus of another, accompanied by the emission of rays.

Alpha decay: The process in which the nucleus of one radionuclide spontaneously releases alpha particles and becomes the nucleus of another radionuclide is called alpha decay.

Decay rate: the probability of radionuclide decay per unit time.

Orbital electron capture: the process in which an orbital electron is captured by the nucleus, so that protons in the nucleus are converted into neutrons and neutrinos are released.

Decay constant: Decay constant is a physical quantity describing the decay rate of radionuclides, which refers to the probability of spontaneous nuclear transition of nuclei in a certain state.

Linear attenuation coefficient: the probability that light is absorbed when it passes through a unit distance in matter.

Mass attenuation coefficient: the absorption probability or attenuation intensity when a ray passes through a unit mass medium, which is also the linear attenuation coefficient divided by the density.

Uranium-radium equilibrium constant: indicates the ratio of the mass ratio of uranium and radium in ore (rock) to the mass ratio of uranium and radium at equilibrium.

Absorbed dose: the expected energy value given to a unit mass of material by electric radiation at a certain point. D=dE/dm, and the absorbed dose unit is Gy.

Average ionization energy: the average energy required to produce ion pairs in a substance.

Anti-collision ability: the average energy lost by ionization and excitation per unit distance when charged particles pass through matter.

Nuclide: an atom with a specific mass number, atomic number and nuclear energy state, and its average life span is enough to be observed.

Particle fluence: the number of particles entering the unit solid sphere cross-sectional area.

Particle fluence rate: indicates the increment of particle fluence per unit time.

Energy fluence: at a certain point in space, the sum of energy injected by all particles into a small sphere centered at that point is divided by the cross-sectional area of the sphere.

Energy flux rate: the total energy of particles entering the cross-sectional area of a solid sphere per unit time.

Specific release kinetic energy: the sum of the initial kinetic energy of all charged particles released by uncharged ionized particles in a substance with mass dm.

Dose equivalent: the weighted sum of absorbed dose and radiation weight factor at a certain point.

Isotope: a group of nuclides with the same atomic number but different mass numbers, that is, different neutron numbers.

Exposure: X=dq/dm, which is a measure of ionization power generated by X-rays or γ-rays.

Exposure rate: the charge generated by gamma rays in space-volume elements per unit mass per unit time.

Dose equivalent index: the limit of annual dose of uniform whole body irradiation.

Isomorphism: Nuclides with the same mass number and atomic number but obviously different half-lives.

Average life: the average survival time of radioactive nuclei. It is the reciprocal of the decadent Changshu.

Ionization energy loss rate: the average energy lost by ionization and excitation per unit distance when charged particles pass through matter.

Equilibrium uranium content: the uranium content at the time of reaching radioactive equilibrium.

Resolution time: the shortest time interval between two adjacent pulses.

Compton edge: the edge formed when Compton scattering angle is 180 degrees when Compton scattering occurs.

Compton plate: a platform formed when Compton scattering angle is zero to 180 degrees.

Cumulative effect: refers to the energy absorption of Y photons by multiple interactions of Y photons in the medium.

Edge effect: secondary electrons are generated near the crystal edge, which may be beneficial to the crystal to lose some kinetic energy outside the crystal and reduce the pulse amplitude.

And the peak effect: two Y photons are absorbed by the detector crystal at the same time to produce a pulse with a large amplitude, and the corresponding energy is the sum of the two photon energies.

Double escape peak: refers to two annihilation photons escaping from the detector without interaction.

Response function: the mathematical expression of the relationship between the pulse amplitude output by the detector and the incident γ -ray energy.

Energy resolution: a parameter that characterizes the resolution of gamma-ray spectrometer to gamma rays with similar energy.

Detection efficiency: characterize gamma ray irradiation rate and detector output pulse 1. Peak-to-total ratio: the ratio of the number of pulses in the whole peak to the number of pulses in the whole spectrum.

Peak-to-Kang ratio: the ratio of the maximum count of the central track of the all-around peak to the average count of Compton Plateau.

Peak-to-total ratio: the ratio of the number of pulses in the whole peak to the number of pulses in the whole spectrum.

Incident intrinsic efficiency: refers to the ratio of the total number of pulses in the whole spectrum to the number of Y photons incident on the crystal.

Intrinsic peak efficiency: the ratio of the number of pulses in the omnidirectional peak to the number of Y photons incident on the crystal.

Source detection efficiency: the ratio of total counting rate to full spectrum Y photon emissivity of radioactive source.

Source peak detection efficiency: the ratio of the number of pulses of the omnidirectional peak to the Y photon emissivity of the radiation source.

Photoelectric absorption coefficient: the absorption probability of photon photoelectric effect.

Photoelectric cross section: the probability that the target atom will produce photoelectric effect per unit area of incident photons.

The ground state of the nucleus: the lowest energy state of the nucleus

Bremsstrahlung: Electromagnetic radiation related to the deceleration or acceleration of high-speed charged particles passing through matter and interacting with Coulomb field.

Auger electron: high-energy electrons jump to the atomic shell after generating electron holes, and release energy at the same time. When the released energy is transferred to an electron in another layer, the electron is emitted from the atom, and the emitted electron is called Auger electron.