X-Ray Vision: Airport Security's Inner Workings

Airport X-ray scanners are used to build a picture of what's inside your bags, allowing security staff to check for anything suspicious. X-rays are electromagnetic waves with high energy, meaning they can penetrate many materials. The X-ray source sends out X-rays in a range of energy levels, which are then picked up by a detector on the other side of the machine. Different materials absorb X-rays at different levels, so the resulting image lets the operator see distinct items inside your bag.

X-rays are electromagnetic waves with high energy that can penetrate many materials

In a dual-energy X-ray system, the X-rays pass through a detector, a filter and then another detector. The detector picks up the X-rays after they have passed through the item being scanned. The detector then passes the X-rays on to a filter, which blocks out the lower-energy X-rays.

Since different materials absorb X-rays at different levels, the image on the monitor lets the machine operator see distinct items inside the bag. Items are typically coloured on the display monitor, based on the range of energy that passes through the object. All X-ray systems use shades of orange to represent "organic", as most explosives are organic. Machine operators are trained to look for suspicious items, including components of improvised explosive devices (IEDs).

The X-ray source will send out X-rays in a range of energy levels. Organic objects block low-energy X-rays to some extent, but not higher-energy X-rays. Plastics block low-energy X-rays better than organic objects, but not as effectively as metal objects, which block almost everything.

Dual-energy X-ray systems have a single X-ray source that sends out X-rays in the range of 140 to 160 kilovolt peak (KVP)

Dual-energy X-ray systems, such as those used in airport security, have a single X-ray source that sends out X-rays in the range of 140 to 160 kilovolt peak (KVP). KVP refers to the amount of penetration an X-ray makes, so the higher the KVP, the further the X-ray penetrates.

The X-ray source will send out X-rays in a range of energy levels. Organic objects block low-energy X-rays to some extent, but not higher-energy X-rays. Plastics block low-energy X-rays better than organic objects, but not as effectively as metal objects, which block almost everything.

In a dual-energy X-ray system, the X-rays pass through a detector, a filter, and then another detector. After the X-rays pass through the item, they are picked up by a detector, which then passes the X-rays on to a filter, which blocks out the lower-energy X-rays.

The X-rays launched from one side of the machine are picked up by a pair of detectors on the opposite side. As your bag enters through the lead-lined curtains, it crosses the path of these X-rays and absorbs some of the energy they carry. The image on the monitor lets the machine operator see distinct items inside your bag. Items are typically coloured on the display monitor, based on the range of energy that passes through the object.

X-ray scanners build a picture of what's inside your bags

The X-ray source will send out X-rays in a range of energy levels. Different materials absorb X-rays at different levels, so the image on the monitor lets the machine operator see distinct items inside your bag. Items are typically coloured on the display monitor, based on the range of energy that passes through the object. For example, all X-ray systems use shades of orange to represent "organic" because most explosives are organic. Machine operators are trained to look for suspicious items, such as components of an improvised explosive device (IED).

Different materials absorb X-rays at different levels, which is shown on the display monitor

X-ray machines used in airports are based on a dual-energy X-ray system. This system has a single X-ray source sending out X-rays, typically in the range of 140 to 160 kilovolt peak (KVP). KVP refers to the amount of penetration an X-ray makes. The higher the KVP, the further the X-ray penetrates.

Different materials absorb X-rays at different levels. This is shown on the display monitor, which allows the machine operator to see distinct items inside your bag. Items are typically coloured on the display monitor, based on the range of energy that passes through the object. For example, while the colours used to signify "inorganic" and "metal" may vary between manufacturers, all X-ray systems use shades of orange to represent "organic" because most explosives are organic. Machine operators are trained to look for suspicious items, including anything that could be a component of an improvised explosive device (IED).

The X-ray source will send out X-rays in a range of energy levels. Organic objects block low-energy X-rays to some extent, but not higher-energy X-rays. Plastics block low-energy X-rays better than organic objects, but not as effectively as metal objects, which block almost everything.

X-ray devices are set up to identify and distinguish between different kinds of objects

The X-ray devices in luggage scanners are more complicated than medical imaging devices. Medical X-rays are only interested in one thing: bones. The trick is that not all X-rays are created equal. Organic objects block low-energy X-rays to some extent, but not higher-energy X-rays. Plastics block low-energy X-rays better than organic objects, but not as effectively as metal objects, which block almost everything.

The machine used in airports is usually based on a dual-energy X-ray system. This system has a single X-ray source sending out X-rays, typically in the range of 140 to 160 kilovolt peak (KVP). KVP refers to the amount of penetration an X-ray makes. The higher the KVP, the further the X-ray penetrates. In a dual-energy X-ray system, the X-rays pass through a detector, a filter, and then another detector. After the X-rays pass through the item, they are picked up by a detector. This detector then passes the X-rays on to a filter, which blocks out the lower-energy X-rays.

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