How Walk through Metal Detectors Work
While traveling airplane you have to pass through a walk-through metal detector for security check up. These security devices have also been used in multiple places like schools, events hall, government offices … etc. They are part of a total security system that includes CCTV, door access control, and so on.
How They Work
How Walk through Metal Detectors Work,Walk-through metal detectors are using pulse induction (PI) technology. The PI systems send powerful, short bursts (pulses) of current through the coil of wire. Each pulse generates a short magnetic field. When a piece of metal passes through the magnetic field, a reflected magnetic field is created. This magnetic field then reacts with the receiver coil, which, in turn, triggers the alarm system. This subsequent current is called the reflected pulse and lasts only about 30 microseconds.
The multi-zone walk-through metal detectors contain multiple coils that create the separate detection zone. They can detect multiple objects, and display all the areas where they can be found. Systems are available with up to 33 zones. There are alarm lights on the side of the unit making it much easier for the security person to find the object. To learn more, take a look at our video about “How Walk-through Metal Detectors Work.”
How Walk through Metal Detectors Work
The Health Physics Society wrote a fact sheet on airport security that said, “Even though magnetic fields [created by metal detectors] are a form of radiation, the radiation the machine emits is nonionizing and does not cause biological damage. Therefore, even repeated exposure to metal detectors has no associated radiation risk.” With this in mind, airport metal detectors provide a very effective and safe method of enforcing security in airports, schools, and businesses.