A New Generation of X-ray Baggage Scanners Based on a Different Physical Principle

Materials

Konstantin Ignatyev²  Peter R.T. Munro²  Deeph Chana¹  Robert D. Speller² 

[1] Department for Transport, Victoria Street, London SW1E 6DT, UK; E-Mail:;Department of Medical Physics and Bioengineering, UCL, Gower Street, London WC1E 6BT, UK; E-Mails:

关键词: baggage scanners;    x-ray refraction;    x-ray phase;    phase contrast imaging;   

DOI  :  10.3390/ma4101846

来源: mdpi

【 摘 要 】

X-ray baggage scanners play a basic role in the protection of airports, customs, and other strategically important buildings and infrastructures. The current technology of baggage scanners is based on x-ray attenuation, meaning that the detection of threat objects relies on how various objects differently attenuate the x-ray beams going through them. This capability is enhanced by the use of dual-energy x-ray scanners, which make the determination of the x-ray attenuation characteristics of a material more precise by taking images with different x-ray spectra, and combining the information appropriately. However, this still has limitations whenever objects with similar attenuation characteristics have to be distinguished. We describe an alternative approach based on a different x-ray interaction phenomenon, x-ray refraction. Refraction is a familiar phenomenon in visible light (e.g., what makes a straw half immersed in a glass of water appear bent), which also takes place in the x-ray regime, only causing deviations at much smaller angles. Typically, these deviations occur at the boundaries of all objects. We have developed a system that, like other “phase contrast” based instruments, is capable of detecting such deviations, and therefore of creating precise images of the contours of all objects. This complements the material-related information provided by x-ray attenuation, and helps contextualizing the nature of the individual objects, therefore resulting in an increase of both sensitivity (increased detection rate) and specificity (reduced rate of false positives) of baggage scanners.

【 授权许可】

CC BY   
© 2011 by the authors; licensee MDPI, Basel, Switzerland.