New progress in the safety inspection technology o

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New progress in explosion-proof safety inspection technology

in recent years, with the complex and volatile international situation, various terrorist activities have occurred one after another, such as explosion, hijacking of aircraft, kidnapping, assassination, armed attack and sending mail bombs. In order to effectively prevent and combat the occurrence and expansion of these criminal activities, the police of various countries have used safety inspection technology and equipment to carry out targeted explosion-proof safety inspections on dangerous goods and prohibited goods. Traditional safety inspection equipment, such as X-ray detector and metal weapon inspection door, can find dangerous goods such as metal weapons and ordinary explosives, and has played an important role in safety inspection. However, in recent years, the weapons equipped by terrorists have become more and more advanced (such as Semtex plastic explosives, glock17 plastic guns, high-precision bombs, etc.), prompting countries around the world to explore and study more advanced new technologies and equipment for security inspection. At present, there are several new safety inspection technologies and equipment that have been put into use and are becoming mature: at present, due to the increasingly perfect inspection function of the X-ray safety inspection system, the use of metal structure explosive devices by terrorists in terrorist crimes is decreasing. In order to avoid inspection, explosive devices with non-metallic structures (such as plastics) have increased. In view of this feature, some developed countries in the world such as the United States, Britain and France have successively developed neutron detectors when the cross-section is increased, which can effectively detect non-metallic weapons such as plastic bombs. The working principle of the neutron detector is to use the neutron beam as the incident source. It can emit neutron beams with stronger penetrating ability than X-rays into luggage packages, and can penetrate any substance including lead. Since neutrons are not charged, they will not cause any damage to hips and ABS tested objects. The neutron beam is sensitive to the reaction of nitrogen atoms. Plastic explosives contain a large amount of nitrogen, and nitrogen-containing objects will be released once irradiated by the neutron beam γ Rays, monitored by sensors γ The existence and energy of rays can be accurately detected by computer analysis. Millimeter wave security inspection camera millimeter wave is an electromagnetic wave between light wave and radio wave. More accurately, it is a narrow electromagnetic spectrum (30-300ghz) between far-infrared and microwave spectrum. The characteristics of millimeter wave are different from microwave and infrared light. It has good penetrability to various insulating materials (such as various clothing fabrics and most building materials). Therefore, it can expose all kinds of metal weapons, lethal weapons or prohibited items hidden in the human body. It is an ideal wave band for safety inspection. Millimeter wave inspection equipment is also very effective for searching weapons and eavesdropping equipment hidden in the wall. The research results of physics show that any object in nature is an energy radiator, including millimeter wave energy, as long as its surface temperature is higher than absolute zero (-273 ℃). The energy of millimeter wave radiation emitted by an object depends on its physical properties and temperature. Millimeter wave energy radiated by human body 1) the design wave energy of the channel is more than that of metal, ceramics, plastic explosives, powdered explosives, clothing, insulating materials, etc., and millimeter wave can penetrate any insulating materials, such as all clothing fabrics and most building materials. Therefore, in front of the millimeter wave camera, people's clothes are missing. Against the contour of the human body, people's coins, buttons, pens, keys and other objects are clearly visible. If you hide contraband items such as pistols, bombs, drugs, etc., you will have a glance. Therefore, millimeter wave camera is the most effective means of human safety inspection and monitoring. The difficulty in the development of millimeter wave security inspection camera is to study a detector that can effectively receive millimeter wave. Millimeter waves cannot be received by photo negatives or detected by photoelectric devices, ionization devices and heat absorption devices like light waves, nor can they be received by ordinary antennas like radio waves, but only by special micro wireless antenna arrays. Millitech company in Massachusetts has been committed to the research and development of millimeter wave safety inspection cameras since 1985. After years of efforts, it has designed a two-dimensional receiving antenna array composed of 256 miniature antennas with a diameter of only 2-3 mm, which has better solved the problem of millimeter wave reception. At present, millitech is further improving this antenna array and developing image scanning recognition and alarm software. Millimeter wave TV camera is a passive camera, which is not affected by any surrounding environment and will not cause any damage to human body and inspected objects. Microwave holography inspection holography usually refers to the holography of visible light waves. In order to find weapons hidden in the clothes or opaque packages worn by the examinees, microwave holography is used. Taking advantage of the strong ability of microwave penetration, using a holographic device with a frequency of 70 gigahertz to carry out "electron beam inspection", the pistol hidden under layers of clothes or in synthetic leather packages can be displayed on the monitoring screen. Klaus mafi belstov has taken UD to further improve the competitiveness of its fiberform process, knives and other items. The microwave imaging device can easily find the prohibited items (such as drugs) hidden in the hidden parts of the human body. Nuclear magnetic resonance detection technology in the molecular structure of different substances, their hydrogen nuclei have different resonance characteristics. The strength of this nuclear magnetic resonance signal is directly proportional to the hydrogen content of the substance. Therefore, nuclear magnetic resonance technology can be used to distinguish explosives and non explosives. First, a transmitter is used to transmit low-frequency radio waves to the luggage, which instantly disturbs the nuclear arrangement inside the item. When the nucleons rearrange themselves, they emit signals, which are immediately analyzed by the system's computer. Since each type of material emits a unique signal, no two compounds have the same signal. Therefore, it is easy to detect explosives or illegal drugs. It can also detect liquid bombs, nerve gas and other chemical weapons. The combination of this magnetic resonance explosive detection system qscan-1000 and line231 X-ray safety inspection system can obtain the best detection effect. At present, it has been used at Los Angeles International Airport and many international airports in the UK. Figure 1 the vacis-1 system installed on the site to inspect the high-pressure oil tank, with the radioactive source on the right and the detector tower on the left

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