At present, our common subway security equipment can be divided into three types: X-ray security equipment, hand-held metal detectors and security doors, among which X-ray security equipment is the most worrying one.
X-ray security inspection equipment is based on the penetrating imaging principle of "X-ray". After computer processing, recognizable images can be displayed on the screen, so as to judge whether to carry dangerous goods.
The National Standard GB 15208. 1-2005 has made clear requirements for X-ray safety inspection equipment, requiring that the inspection dose of the security instrument should be less than.
Now we use X-ray security equipment, and the radiation dose is about110 stipulated by the national standard. If you want to compare it with hospital X-rays, the radiation dose received by a chest X-ray in the hospital is about 50μGy. It takes about 100 security checks to reach the radiation dose received by chest X-rays.
Therefore, the X-ray dose used for subway security inspection is very small.
After the goods pass the security check, the dose of X-ray pollution can be ignored.
Extended data
X-ray security detector is an electronic device that uses X-ray scanning imaging technology to detect luggage safely. It consists of X-ray generator, X-ray detector, image processing system and so on, and judges the safety of articles according to scanning imaging.
X-ray security inspection instrument belongs to low-risk radiation device, and the radiation amount is far less than that of medical X-ray machine.
The radiation dose of the light baggage security device is far less than that of the X-ray machine for medical diagnosis, and the radiation around the machine is very weak, so even full-time operators can work safely without protection.
The radiation dose of chest X-ray examination in hospital is about 50μGy. According to this calculation, staying near the baggage X-ray security device for 50 hours is equivalent to a medical X-ray chest examination.
According to the calculation of passing the subway security check twice a day for 365 days a year, the annual radiation dose of subway passengers due to subway security check does not exceed 0.0 1mSv( 10μSv), which is only equivalent to the natural background radiation dose of 1.5 days or the radiation dose of flying for 2 hours, so it will not cause harm to passengers.
References:
Baidu encyclopedia -X-ray security instrument