Stand Alone XBIS machines at airports commonly work on the principle of

XBIS stands for X-ray Baggage Inspection System. These machines operate on the principle of electromagnetic radiation, specifically using X-rays. X-rays are high-energy electromagnetic waves that can penetrate solid objects. As baggage passes through the scanner, X-ray beams are directed at it, and detectors measure the attenuation (absorption or transmission) of the rays. Different materials (organic, inorganic, and metals) absorb X-rays differently based on their density and atomic number, allowing the system to generate a color-coded image of the contents.

• Ion mobility spectrometry (IMS): This is the principle used in Explosive Trace Detectors (ETD) to identify vapors or particles of explosives or narcotics.
• Gas chromatography: Used for chemical analysis and identifying substances, often in specialized laboratory or detection equipment.
• Backscatter technology: A specific X-ray imaging technique that detects reflected (scattered) rays, but the fundamental physical category remains electromagnetic radiation.