Bag Scanners: Detecting Threats In Airport Security

Airport scanners are designed to detect prohibited items and illicit substances, including drugs, weapons, and explosives. They can identify metallic and non-metallic objects, as well as organic materials. The two primary types of luggage scanners used at airports are X-ray scanners and Computed Tomography (CT) scanners, which use X-rays to penetrate luggage and create images of the contents. Full-body scanners, on the other hand, use millimeter waves or backscatter X-rays to detect potential threats on a person's body. These scanners play a crucial role in maintaining security and ensuring the safety of passengers.

Metal objects

The X-ray images produced by the scanners use specific colours for metallic objects, with metal objects appearing in dark green or blue. Additionally, the scanners may emit a beeping sound when metal objects are detected. This helps security personnel quickly identify and investigate any potential threats.

Metal detectors, which are often integrated into the scanners, create magnetic fields through electricity. When metal objects pass through these fields, the magnetic radiation bounces back, triggering an alert and indicating the presence of metal. This technology is designed to ensure the safety of passengers by detecting potential weapons or other unlawful devices.

While metal detectors and scanners are effective at spotting weapons, they are not perfect. False alarms can occur, and there is a possibility of malfunction. Additionally, some scanners may not provide clear images or accurately detect the precise type of metal. However, even blurred images can raise suspicion and prompt further investigation by security personnel.

Liquids and gels

The general rule is that liquids, gels, creams, pastes, and aerosols must be in containers with a maximum capacity of 100ml and placed within a transparent, re-sealable plastic bag, which is

Drugs and explosives

Airport scanners use X-ray technology to detect organic materials, such as drugs and explosives. While scanners cannot directly identify these substances, they can provide visual clues that may indicate their presence. For example, unusual shapes or masses in luggage that don't match other packed items, or suspiciously wrapped packages that don't resemble typical travel items. Security officers are trained to spot these signs and can take further action if they suspect illegal substances.

In addition to X-ray scanners, metal detectors are also used to locate potential weapons. These use non-ionizing radiation to scan travellers and ensure they are not carrying hidden items. Metal detectors can identify metallic objects through the clothing and in luggage.

Newer types of scanners include the AIT (or ATI) scanner, which creates a 3D X-ray image of the body and can detect drugs and weapons. Another is the terahertz scanner, which uses waves in the terahertz range to produce real-time imaging of moving passengers.

To ensure safety, security personnel will manually inspect any luggage that appears suspicious.

Paper money

Airport scanners are not designed to explicitly detect paper money, but they can do so indirectly. When luggage passes through an X-ray scanner, the contents are displayed on a screen based on their density and material composition. Paper money, especially in large amounts, has a distinctive appearance on the X-ray image. It may appear as stacks of uniform rectangular shapes that can be easily distinguished from other items.

Advanced Imaging Technology (AIT) scanners create detailed images of a passenger's body to detect concealed items. While not designed to detect cash, if a passenger is carrying a large sum of money, the scanners might reveal unusual bulges or shapes that could prompt further inspection.

Passengers are often asked to empty their pockets before passing through a full-body scanner, as the machine will detect any items present. Some people have tested this by leaving banknotes, napkins, or boarding passes in their pockets and have been asked to show these items to security staff.

In some countries, such as the US, passengers are required to completely empty their pockets before passing through a full-body scanner. In other countries, the rules may be less strict, and small amounts of paper money in a pocket may not trigger the scanner. However, it is always best to comply with security requests and declare any large sums of money to avoid suspicion of money laundering or other financial crimes.

Electronic devices

Most electronic devices are fine to take through airport security in your hand luggage. However, it is worth noting that some larger items, such as hairdryers, are not permitted in your carry-on baggage and must be packed in your hold luggage. This is because they are considered potential safety hazards due to their powerful motors.

Laptops and tablets are subject to special rules at airport security. While they can be taken through security, they must be removed from their cases and placed in a separate tray to go through the scanner. This is a standard procedure and is done to allow for a clear and unobstructed scan of these items. It is also worth noting that you may be asked to turn on your devices to prove that they are functional and not concealed explosives.

Additionally, there are rules regarding battery-powered devices. Any devices with lithium-ion or lithium-metal batteries must be packed in carry-on baggage only. This is because these batteries are considered a fire risk and are not permitted in checked baggage. Spare batteries, power banks, and e-cigarettes also fall into this category and must be declared to the airline.

It is always a good idea to check with the specific airline and airport you are travelling through for any additional restrictions or requirements. Some airports may have different procedures, and it is important to be aware of these to ensure a smooth journey through security.

Frequently asked questions