X-ray Imaging and Back Scattering Technology Widely Used at Airport Inspection
Since the explosion attack occurred all over the world, the national civil aviation airport security level has increased to an unprecedented height. In many airports, you can also see hand-held iron bars, security guards at the entrance of the terminal, and even the X-ray security checker for your baggage and your body at the entrance of the terminal, and how much do you know about the x-ray imaging?
What's X-ray Imaging Technology?
X-rays can be divided into hard X-rays with higher energy and soft X-rays with lower energy, and their energy is stronger than ultraviolet rays. The X-rays used for security are located in the soft X-ray band. The electrons emitted from the source are accelerated to obtain higher energy and then blast to heavy metal atoms. When high-energy electrons interact with the extranuclear electrons of the bombarded atom, the electrons lose energy and produce X-rays, that is X-rays. We can see objects with our eyes because of the light, the light can be reflected on the surface of the object, or transmitted through the object, or the object itself will emit light (light source).
What's Back Scattering Technology?
Back Scattering Technology is a non-contact human body security technology that images the surface of the human body and examines it in this image. Irradiate the human body with a certain amount of X-rays, collect the X-rays scattered back from the surface of the human body, and then perform statistical analysis to obtain images of the surface of the human body, all kinds of contraband carried by the people and hidden under the clothing (such as guns, bullets, knives, explosions, drugs, etc.) will be displayed on the image. Those substances with higher atomic numbers than human bodies (such as metals things, ceramics, etc.) will be darker than normal humans on the image. Those substances with lower atomic numbers (such as explosives, drugs, etc.) will be brighter than normal humans on the image. This enables a non-contact inspection of the human body surface.
Is the Back Scattering and X-ray Scanning System Harmful to Human Body?
Since X-rays are not required to pass through the body, it is possible to minimize the damage of the radiation to the human body by selecting the appropriate X-ray energy. The US Food and Drug Administration (FDA) Equipment and Radiation Health Center (CDRH), the National Institute of Standards (NIST), and third-party radiation protection organizations have conducted joint testing of X-ray human body detection equipment used at US airports. On average, the X-ray backscatter scan of a security check produces a dose of between 0.000015 and 0.00088 mSv, which is equivalent to flying at high altitude for 0.5 to 2 minutes. Taking a cigarette is equivalent to accepting 14 to 400 such scans. X-ray chest X-ray for medical diagnosis is equivalent to 11 to 600 such scans.
By comparison, it can be found that even the people scanned by human body safety inspections frequently when entering and exiting the airport or others sith with this X-ray backscatter screening inspection system and receive X-ray backscattering are negligible. Studies by X-ray backscatter screening at the Marquette University School of Engineering in the United States have shown that although the X-rays of such devices penetrate the surface of the human skin, the risk to human health is still below the health standard.
In fact, living organisms are always receiving ionizing radiation and electromagnetic radiation. However, organisms have a strong self-healing mechanism. At any time, cells are destroyed, cells are repaired at any time, or new replacement cells are produced. Moreover, the number of cells that make up an organism far exceeds the number of boulders in a pyramid. Organisms are more difficult to destroy than the bombarded pyramids.
Therefore, we can safely accept X-ray imaging and backscattering systems or millimeter-wave systems for airport security.