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Security Metal Detecting A-Z Glossary

Security Metal Detecting Glossary

Common terms associated with security checkpoint screening using metal detectors

Access Point

An entry or exit of a checkpoint screening area


An audio or visual signal emitted by a metal detector when it detects metal. In a security application, the source of the alarm must be determined before a patron is permitted to leave a checkpoint screening area


A term often used to describe the frame of a walkthrough metal detector

Audio adjust

The control used to adjust the volume level of sounds emitted by a metal detector

Bar Graph      

A series of lights that indicate metal detection activity


An umbrella term that refers to setting up a detector's programmes to meet specific security needs.


An area where security screening occurs.


The ability of metal to conuct electrical currents (e.g eddy currents)


An object (e.g, pistol, knife, coin, keyring, etc) through which electrical currents can pass. Both ferrous and non-ferrous metal objects are conductors.

Detection pattern

A pattern within an electromagnetic field matrix. In the case of a walkthrough detector, the pattern forms along the vertical axis of the side panels, balloons outwards and evantually tapers off. The size of the pattern varies depending on the geometries of the transmitter and receiver coils; the type and strength of the transmission signals; and the size and nature of the metal item.


An optional accessory used in conjunction with hand-held detectors to monitor alarms privately

Eddy currents

Also known as Foucalt currents. The primary electrical phenomenon responsible for producing detection signals. The detector's electromagnetic field generates eddy currents that flow throughout the surface of a metal object. Eddy currents use up electromagnetic field energy - resulting in a power loss that is sensed by the detector and reported via an audio or visual alarm. The flow of eddy currents is proportional to radio frequency and the conductivity of the metal object.

Electromagnetic field

An invisible field, generated by the alternating radio frequency cueent surrounding the transmitter coil, which radiates into the surrounding environment, be it rock, ground, air, water etc. The presence of a metal object results in a disturbance of the electromagnetic field, which is then measured by the detector and reported via an audio or visual alarm.

Electromagnetic induction

Current induced in a coil (or conductive object) due to changes in the electromagnetic field passing through the coil or object.

Hand carried items

Items such as hand-bags, luggage, back-packs, briefcases, cameras etc, which must be inspected visually and/or manually. Walk-through and hand-held detectors are not recommended for security inspection of hand carried items.

Induced current

A current flowing into a conductor during the presence of an electromagnetic field. With the exception of eddy currents, induced or secondary currents flow only where there is a complete circuit or closed loop. (Eddy currents themselves are closed loops).

Infrared analysis
(IR analysis)

A type of sensor enabling the detector to ignore environmental interference while it detects metal. The infrared analysis renders the detector inoperable when the archway is empty, thereby reducing the likelihood of nuisance alarms. The sensor also helps generate a traffic count

Interference reduction switch

A switch used to reduce the detection sensitivity of the Garrett Superscanner thereby lessening the likelihood of outside interference from nearby metal such as flooring rebar


A liquid crystal display that visually reports the calibration and operational information of a walk-through metal detector.


An instrument that measures magnetic intensity, especially that of the earth. It is typically used to locate ferrous materials , particularly iron. A magnetometer does NOT directly detect the presence of metal. (See Metal Detector).

Manual inspection

The inspection method required for all hand carried items prior to their admission into a screened area.


A matrix by defenition is something within which something else originates. In the case of a walk-through detector , it is the area within the archway which is "illuminated"by the transmission of an electromagnetic field.


An integrated circuit comprising the necessary components of a small digital computer. A microprocessor enables the detector to perform numerous functions automatically instead of manually.

Nuisance alarm

A detector alarm triggered by interference from nearby metal objects or from electrical or mechanical environmental noise due to large motors, computers, video monitors, fluorescent lighting etc. The Garrett Magnascanner's infrared analysis helps reduce the occurance of such alarms.

Pack mule

A person recruited as a proxy to smuggle forbidden items through a security checkpoint screening system.

Pack mule

A person recruited as a proxy to smuggle forbidden items through a security checkpoint screening system.


The ability of a detector to "see through" a variety of materials, such as air, skin, wood, rock, water etc. in order to locate metal items.


The ability of a detector to perform the functions as specified by the manufacturer.

Pulse induction

The process of a current passing through a transmitter antenna coil intermittently. During the passive period, the antenna senses a secondary electromagnetic field caused by the presence of a conductor. Garrett's Magnascanner walkthroughs feature pulse induction circuitry.

Receiver coil

of a metal detector, which receives, processes and acts upon information generated by the presence of metal according to preset or manual calibration.

Random screening

A screening method in which people are randomly chosen to undergo inspection for forbidden items.

Screened area

An area protected by security checkpoint screening. Only persons who have undergone a thorough security inspection are permitted inside this area. Also referred to as a sterile or secured area.


The ability of a metal detector to respond accordingly to the size, shape, material composition and location of a metal object within the detector's electromagnetic field. Increasing or decreasing the sensitivity setting alters the degree of the detection response.

Sensitivity controls

A control used to regulate the sensitivity of the detector. The sensitivity level is typically set to a level that is high enough to detect the smallest forbidden object.


A general term that refers to the electromagnetic data received by the detector and the subsequent audio and/or visual response.


The ability of the detector's circuits to adhere to pre-determined operating designations. Stability is essential to any quality detector as instability can cause false alarms and detection errors.

Tamper alarm

A visual and/or audible alarm that activates upon any unauthorised attempt to alter a walk-through's control settings.

Transmitter coil

Wires bundled together to create a coil into which an electrical current is induced and an electromagnetic field results.

Unsecured area

The area located outside of any security checkpoint screening system.

Unexplainable alarm

An alarm whose source is unknown. An individual who triggers an unexplainable alarm is prohibited from entering the secured area until security personnel determine the cause of the alarm.

Uniform detection   

A term used to describe the head-to-toe, uniform detection area within the archway of a walkthrough metal detector.
Visual indicator
A general term that refers to the alarm light, ready light, bar graph or POWER ON light of hand-held and walk-through metal detectors.

Volume control 

A control used to limit the voltage and/or current inside an audio amplifier, thereby controlling the volume of a metal detector alarm.

Walkthrough metal detector

A metal detector resembling a door frame, which determines the presence of forbidden metal items on a person's body and/or in their clothing as they pass through the archway.
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