The airport security detector is used to detect metal objects which may be hidden about the person passing through the gate.
It works on the same principle as a metal detector, by means of electromagnetic induction. When a section of metal passes through a magnetic field, the field generates electric eddy currents that circulate in the metal. These currents then create their own magnetic field and a receiver which is planted in the gate picks up the field and sets off the alarm.
People with pacemakers are not allowed through these gates as the electromagnetic induction may interfere with the pacemaker, which can produce disastrous consequences.
The walk-through detector is usually used in conjunction with an X-Ray baggage handler. All luggage is placed on a conveyor belt and passes through an X-Ray machine. The operator watches a monitor, which shows the X-Ray in real time, looking for suspect baggage contents.
Recent innovations include X-ray baggage handlers with colour displays, allowing easier identification of baggage contents.
