Airport Scanners: Liquid Detection Technology Explained

Airport scanners use advanced X-ray technology to detect liquids. The new generation of scanners can detect potential threats with great accuracy, and their enhanced imaging capabilities can provide visual hints that may indicate the presence of explosives or drugs. These scanners can also detect non-metallic objects such as plastics, ceramics, and glass through their density and atomic number. The technology is expected to be implemented in airports across the United Kingdom, Europe, and North America.

X-ray technology

Additionally, X-ray scanners can identify organic materials, including food and explosives. These materials appear distinctively on the monitor, often in an orange hue. This capability is essential for detecting potential threats, such as liquid explosives or contraband. The technology can also detect indications of drugs, providing visual hints that may suggest the presence of prohibited substances.

The latest generation of X-ray scanners, known as Computed Tomography (CT) scanners, create 3D X-ray images of luggage contents. These scanners provide an even more detailed view, allowing security staff to thoroughly inspect baggage for prohibited items. Airports across the world, including Shannon Airport, have started adopting this state-of-the-art technology, investing millions of dollars to enhance security and improve the passenger experience.

Density and atomic number

The density and atomic number of an object are crucial factors in how airport scanners detect liquids and other items. Airport baggage scanners use advanced X-ray technology to see through dense materials and reveal their contents. The scanners create detailed images that allow security officers to identify items based on their density and atomic number. Objects with different densities and atomic numbers interact with X-rays in distinct ways, resulting in unique images that trained operators can interpret.

Non-metallic objects, such as those made from plastics, ceramics, or glass, are identified through their density and atomic number. These properties determine how much X-ray radiation they absorb or scatter, making it possible to detect items like plastic explosives or contraband that pose threats to aircraft security.

Metallic objects, such as knives, guns, and other potential weapons, are easily detected due to the X-rays' interaction with metal. These objects typically appear blue or green on the security monitor, depending on their density.

Organic materials, including food, liquids, and explosives, can also be identified through their unique interactions with X-rays. They often appear orange on the monitor. While scanners cannot directly identify explosive or drug substances, the detailed images they produce can provide visual hints that may indicate the presence of such substances.

The latest generation of airport scanners employs CT technology to create 3D X-ray images of bag contents, enhancing the detection of prohibited items. These scanners are designed to streamline the security process by allowing passengers to keep more items in their carry-on bags, such as laptops and liquids.

Metallic objects

Metal detectors and millimetre wave machines are crucial in detecting metallic objects and preventing dangerous items from being transported onto aircraft. They use low-energy, non-ionizing radiation to scan surfaces and detect hidden metallic objects.

Airport baggage scanners, which utilize advanced X-ray technology, can also detect metallic objects. Different materials react differently to X-ray radiation, creating distinct images that trained operators can easily identify. Metallic objects show up as blue or green on the monitor, depending on their density. This makes it easy for security personnel to identify prohibited metallic items such as guns, knives, and other weapons.

Even small parts of firearms, such as screws or springs, can be detected due to their metallic properties. The detection of metal can also raise suspicion regarding the presence of explosive devices, which often have metallic components such as wiring or casings.

Millimetre wave scanners are another technology used to detect metallic objects on a person's body. These scanners can identify metallic items, including weapons, explosives, and drugs hidden under clothing. They emit non-ionizing radiofrequency waves, which are reflected back to the machine, creating an image of any hidden objects.

Organic materials

Airport baggage scanners are designed to ensure the safety of air travel by meticulously inspecting the contents of travellers' luggage. These scanners can detect organic materials, such as food or explosives, which appear orange on the monitor. This capability is due to the distinct interaction between different materials and X-ray radiation, creating unique images that trained operators can easily identify.

The advanced technology in airport scanners enables the sensitive identification of organic materials, enhancing their detection capability. This makes it easier for security personnel to detect prohibited items or suspicious objects, such as explosives or drugs, within seconds. While scanners cannot directly identify these substances, the improved imaging capabilities provide visual hints about their presence.

The scanners create detailed images that allow security officers to identify items based on their density and atomic number. This means they can distinguish between various substances, including organic materials, and detect indications of substances like explosives or drugs. The use of CT technology further enhances detection by creating a 3D X-ray image of the bag's contents, providing a more comprehensive view for security staff.

The implementation of this state-of-the-art technology is already underway at airports such as Shannon Airport, with a plan to introduce it across the United Kingdom, Europe, and North America. This new generation of scanners is expected to streamline the security process, allowing passengers to keep more items in their carry-on baggage. The TSA has invested significantly in these scanners, recognising their potential to enhance aviation security and improve the passenger experience.

Explosives and drugs detection

While airport scanners cannot specifically identify liquids, they can detect explosives and drugs. This is done through a combination of X-rays, millimeter waves, and computed tomography (CT) scans. These scanners can detect objects with different densities, including drugs hidden in luggage or on a person. Organic materials, such as drugs, appear differently on X-ray images compared to metal or plastic. For example, metals show up as dark orange or blue, while organic materials like food, paper, or drugs appear as shades of green or lighter colors.

Drugs hidden in clothing or strapped to the body can be detected by millimeter-wave scanners, which identify unusual shapes or densities that stand out against the natural contours of the human body. The software flags any dense material that doesn't match the expected density of normal items. In addition, drugs concealed in irregular packaging, such as within electronics or hollowed-out items, can stand out during an X-ray scan due to their unusual shape or density.

Explosive detection is commonly used at airports and is based on the fact that explosives usually contain nitrogen. Traditional colorimetric tests have a disadvantage as some explosive compounds, such as acetone peroxide, do not contain nitrogen and are harder to detect. More advanced techniques, such as mass spectrometry and X-ray machines with computed axial tomography, can detect explosives by looking at the density of items and comparing reflected ultraviolet, infrared, and visible light measurements.

To enhance explosive detection, a detection taggant can be added during the manufacturing process, as required by the Montreal Convention 1991. An example is Semtex, which now includes DMDNB as a detection taggant. Dogs are also sensitive to this compound and can be used to detect explosives, although their effectiveness decreases as they become tired or bored.

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