Detecting contaminants is the primary use of X-ray inspection systems in food and pharmaceutical manufacturing, and it is vital to ensure that all contaminants are completely removed regardless of application and packaging type to ensure food safety.
Modern X-ray systems are highly specialized, efficient and advanced, and are used in a wide range of industries for inspection, including medical diagnostics, food and pharmaceutical product inspection, construction (structural, mining and engineering), and security. In the security field, they are used to “see” inside luggage or packages. Food and pharmaceutical manufacturers also rely on X-ray systems to detect and remove contaminated products from production lines to protect consumers, reduce the risk of product recalls and maintain their brands.
But how do X-ray systems detect contaminants? This article explains what X-rays are and how X-ray inspection systems operate.
1. What are X-rays?
X-rays are one of several naturally occurring radiations and are an invisible form of electromagnetic radiation, like radio waves. All types of electromagnetic radiation are a single continuum in the electromagnetic spectrum, arranged according to frequency and wavelength. It starts with radio waves (long wavelength) and ends with gamma rays (short wavelength). The short wavelength of X-rays allows them to penetrate materials that are opaque to visible light, but they do not necessarily penetrate all materials. The transmittance of a material is roughly related to its density – the denser it is, the fewer X-rays it transmits. Hidden contaminants, including glass, calcified bone and metal, show up because they absorb more X-rays than the surrounding product.
2. X-ray Inspection Principles Key Points
In short, an X-ray system uses an X-ray generator to project a low-energy X-ray beam onto a sensor or detector. The product or package passes through the X-ray beam and reaches the detector. The amount of X-ray energy absorbed by the product is related to the thickness, density and atomic number of the product. When the product passes through the X-ray beam, only the remaining energy reaches the detector. Measuring the difference in absorption between the product and the contaminant is the basis of foreign body detection in X-ray inspection.