There was a rumor online thatsecurity scannerRadiation has safety issues, and some people are even concerned that food exposed to radiation may spoil. In fact, although the internal image of the object is obtained by irradiating it with X-rays, the radiation of the security inspection machine is much smaller than that of the X-ray equipment. This is mainly because security inspection equipment does not need to reach the resolution of medical diagnosis level, it only needs to differentiate imaging for different substances.

According to the national standard GB15208.1-2005, the single inspection dose of the X-ray security inspection instrument should not exceed 5 μ Gy/h (unit of current radiation energy and absorbed dose), and the X-ray dose should be less than 5 μ Gy/h at any position 5 centimeters away from the outer surface of the equipment (including the equipment inlet and outlet). This standard is the same as that of the US FDA.

In fact, the X-ray radiation dose of the security inspection machine is much lower than the national standard. Taking a certain brand of X-ray security inspection equipment used in Beijing subway as an example, according to the technical data of the enterprise, the radiation dose for a single detection is 0.5 μ Gy, and the radiation dose at 5 centimeters on the outer surface is 0.7-0.8 μ Gy/h, which is only one tenth of the upper limit of the national standard. (Note: "Absorbed dose" refers to the amount of energy absorbed by human tissue per kilogram of radiation, measured in "gray" and represented by the symbol Gy.). 1Gy=1J/kg)

According to the report by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), the radiation dose for a medical X-ray chest X-ray examination is 50 μ Gy.

If we have to compare the two, it takes 100 times to reach the radiation dose that a chest X-ray can receive by entering the security screening machine. Of course, radiation dose is not simply additive, just like soaking in hot water at 40 ℃ for 1 hour is not equal to soaking in hot water at 80 ℃ for half an hour, their effects on the human body are * different.

L3 X-ray machine safety inspection system