What does an airport scanner see

Security technology How does a baggage scanner work?

X-rays are generated in a vacuum glass tube. A high voltage is applied between two electrodes and the negative pole, the cathode, is strongly heated. This causes negatively charged electrons to escape, which are accelerated to the positive pole, the anode. There they arrive at about half the speed of light and hit the atomic nuclei of the copper anode. The atomic nuclei suddenly brake the electrons. The kinetic energy of the electrons is mainly converted into heat; but one percent is given off in the form of X-rays.

The X-ray scanner irradiates the luggage with different wavelengths. As a result, the device can recognize the material of an object in addition to the shape. Soft, organic substances - such as cheese - allow all wavelengths through. They are shown in orange. Steel is only permeable to short-wave, i.e. particularly high-energy, X-rays that produce a blue image.

The inspector can already see from the shape and color of the X-ray image whether it is a dangerous object. However, only a look in the suitcase brings ultimate security.

Due to the x-ray, there could be plastic explosives in the luggage. In this case, the suspicious item turns out to be a harmless package of cheese. Protected from attacks by the luggage scanner, the aircraft can safely take off on vacation.