Introduction to Airport Security Inspection Technology and Principles（2）
5. Technology used to inspect suspiciously dangerous liquids, explosive solid powders, and drugs:
Laser Raman technology Laser Raman technology is an analysis method based on Raman scattering using laser as a light source. When a substance molecule is irradiated by light radiation, the irradiated light is absorbed and re-scattered due to the molecular vibration or the transition of the rotational energy level. The wavelength of Raman scattering is related to the structure of the substance and can be used as a basis for qualitative analysis. Intensity can be used as a basis for quantitative analysis. Laser Raman technology has a wide range of applications in security inspection, environmental protection, food, medicine and other fields.
6. Techniques used to check suspicious liquids:
Permittivity measurement technology (microwave detection) The relative permittivity is a physical quantity indicating the degree of polarization of a medium under the action of an external electric field, and is related to the polarity of a substance molecule. Molecular polarity refers to the unevenness of the charge distribution within the molecule. According to the characteristics of the dielectric constant of liquid articles, it is possible to distinguish flammable dangerous liquid articles with lower dielectric constant from other liquid articles to a certain extent.
7. Techniques used to inspect metal carried by persons:
Common products of metal detection technology are metal security gates and hand-held metal detectors. The security gate can generate an alarm for passing metal objects because the two door panels are equipped with sensors that can transmit and receive alternating electromagnetic fields. When the metal conductor is excited by the alternating electromagnetic field, an eddy current is generated in the metal conductor, and the current emits a magnetic field with the same frequency as the original magnetic field but in the opposite direction. The metal detector detects the vicinity by detecting the presence of the eddy current signal. Whether there is a metal object. The transmitter emits exciting electromagnetic waves, and the receiving sensor receives the signal of the metal object. The receiving sensor detects the signal generated by the eddy current, and then undergoes a series of circuit amplification processing. When the signal reaches the set value, it will be in the form of sound and light. An alarm is generated.
Due to the huge flow of people at the airport, the responsibility for safety is also very heavy.
The purpose of airport security is to prevent passengers from taking guns, military or police weapons and their imitations, explosives, controlled knives, flammable and explosive materials, corrosive materials, poisons, radioactive materials and other items that endanger flight safety. Bring on board the plane through personal, hand-carried luggage, checked luggage, or checked cargo.
Each technology has its applicability, so airport security checks combine multiple technologies to ensure safety. In addition, the equipment is auxiliary, and the operating skills and standardization of the inspectors are also very important to improve the level of security inspection.
Introduction to Airport Security Inspection Technology and Principles（2）- Safeagle