For those who need a security check every day to take the subway, it seems that it is really a hassle to go through security. There are even many people who say that security screening machines have radiation, and frequent security checks are harmful to the human body, especially pregnant women. So, what is the truth? Does the security machine really have such a large amount of radiation? I told you about the security check today.
Rumors: Security is harmful to the human body
Truth: Security is not harmful to the human body
I believe that many people will go through security checks when they go out, whether they are by plane, by train, or even by subway every day, they have to go through security inspections over and over again. Security is very troublesome, but it is very useful for potential dangers. Let's talk to you about the security checkpoints and security gates that are rumored on the Internet.
The security inspection machine is also called the security inspection X-ray machine, or the baggage security inspection machine, which is mainly used for security inspection of luggage. The principle of this kind of security inspection machine is very simple, that is, the ability to use X-rays to penetrate substances. The density is different, the thickness is different, the composition is different, and the penetration ability of x-ray is also different. X-ray machines are based on the ability to penetrate different substances to identify objects in the baggage.
The security inspection machine can not only recognize the shape of the object, but also display the color, and the color of each substance is different. The staff judges the contents of the bag by observing different colors, such as organic items such as paper, clothes, and various foods, usually showing orange. Mixed materials and light metals, such as those containing sodium, silicon, and aluminum, are usually shown in green. Iron, copper, silver, etc. are shown in black and blue. The degree of lightness and darkness of the above various colors depends on the density and thickness of the material.
Because the security machine works by X-rays, some people start to worry about whether their luggage will be contaminated after passing these X-rays. In fact, this is completely a big problem, because the X-ray in the security machine has a small power and is detected once. The received radiation dose is less than 5 micro-Swarth, far from affecting the human body. Therefore, people It is not necessary for the baggage to be contaminated because the baggage has passed the security checker.
Next, let's talk about the security gate. The security gate, also known as the metal detector door. Mainly to detect the metal weapon carried on the passenger. The principle is also very simple, that is, the principle of electromagnetic induction is utilized. Rapidly changing magnetic fields are generated on both sides of the security door. These magnetic fields do not affect the human body, except for metals, because the metal generates eddy currents under rapidly changing magnetic fields, and eddy currents generate a magnetic field. When the security gate detects this When a new magnetic field is applied, the security door will automatically sound or flash.
Some people have aversion to security checks. In fact, when they feel that they have passed the security check, the magnetic field generated by the security gate is harmful to the human body. This is also completely unnecessary, because the security door is not a security X-ray machine, it only produces electromagnetic fields, and does not produce ionizing radiation. Moreover, this electromagnetic field is very weak, only about 1 micro-tesla, this data is several times different from the 30 micro-tesla of the national "passive metal detector door general technical specification".
Furthermore, let us think from another angle. If the security gates are really harmful to the human body, then why are the security inspection staff who are standing next to the security gates for many years, why are they not fully armed? Why do you still choose to stay on?
Therefore, those who are often worried that security screening machines or security gates are harmful to the human body can really relax their minds. These are the situations that are often encountered in daily life. If it is really harmful, I believe the state will not allow it. Security inspection machines and security doors are not harmful to the human body.