Metal Detection Introduction Page
Walk-through Metal Detectors
People only purchase metal detectors because of a potential
threat of violence or to protect valuable assets. The fact that you
are reading this means that you are either an existing user of metal
detectors, or are contemplating purchasing one.
Modern detectors fall under two general categories, single-zone
and multiple-zone. They operate using either the pulse induction or
continuous wave technique. They can be either continuously active
or sensor activated. A continuously active detector is never
deactivated, whereas, sensor activated units employ an opto-electronic
device, usually infrared (IR), that deactivates the detection circuitry
until the IR beam is broken by a person passing through it. Be wary
of sensor activated technology as security can be easily breached.
The single-zone technology that has been in use for more than 30
years is being superseded by multi-zone technology. In multi-zone
detectors the archway is divided into a number of horizontal zones.
This allows the height at which a weapon is being carried to be
displayed. Each zone, in the case of a true multiple zone detector,
can be considered as an individual metal detector that has been
housed in a single frame assembly. The sensitivity of each zone can
be precisely controlled. The multiple- zone concept can be extended
further by subdividing the horizontal zones into three sectors.
This permits the location of a weapon to be precisely pin pointed.
In addition to showing the height at which it is carried it also
identifies if it is in the center, left or right of sector of the
detector.
Both single and multiple-zone detectors transmit low intensity
magnetic fields that interrogate metal objects that pass through
them. A transmitter generates the magnetic field that reacts with
the metal objects in its field and a receiver measures the response
from this reaction. Pulse induction detectors typically have a
transmitter panel and a receiver panel with a cross piece that
separates them. Pulses of magnetic energy are repetitively generated
by the transmitter and pass through the person being screened to
the receiver panel. When passing through a multiple sensor
continuous-wave detector, the person being screened is scanned from
both sides by a continuously oscillating magnetic field.
Hand Held Detectors
Hand held detectors are designed primarily to compliment scanning
by walk-through metal detectors. It must be emphasized that hand
scanning is no substitute for walk-through metal detection screening.
A properly conducted hand held detector search needs to be very
systematic and requires skill. Done correctly, it is both time
consuming and physically demanding as all parts of the subject must
be carefully scanned.
Walk Through
Hand Held
For more information - please click here to contact us.
|
