PAST
X-RAYS IN FOCUS PRESENT
FUTURE
Image credit: Smiths Detection
X-radiation (X-rays) is a form of electromagnetic radiation fi rst discovered by Wilhelm Röntgen in 1895. However, it was Thomas Edison who developed the fi rst commercial application for X-ray with medical radiography. Since then, many applications have been developed in the medical and industrial spheres. Amir Neeman focuses on the homeland and aviation security applications of X-rays in the past, in the present and in the future.
X-rays have a wavelength of 0.01 - 10 nanometres and energies of 100 eV - 100 keV - between UV and gamma radiation in wavelength - and are sometimes referred to as Röntgen radiation.
Early X-ray Systems
First generation X-ray systems were based on X-ray fluoroscopy, which is an imaging technique used to obtain real-time moving X-ray images of objects through the use of a fluoroscope. A fluoroscope consists of an X-ray source and fluorescent screen between which an object is placed. Modern fluoroscopes couple the screen with an X-ray image intensifier and a video camera, which allows the images to be recorded and played on a monitor. The initial fluoroscopic X-ray systems, however, did not use any image intensifiers and relied on the natural X-ray images. Fluoroscopic equipment is typically
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used in portable scanners that screen mail and small packages for explosive devices. Despite their small size, portability and the ability to view images in real-time using low- energy X-rays (and consuming less power),
“…fl uoroscopic equipment is typically used in portable scanners that screen mail and small packages for explosive devices…”
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most of the fluoroscopic X-ray systems originally manufactured contained an X-ray radiation source (rather than an electronic X-ray tube). This means that far more stringent safety precautions had to be put in place for the operator. They also have a relatively small viewing area, necessitating the creation of a dark-room environment, and had low penetration capabilities since they use low- energy X-ray sources (needed to ensure such systems are safe to use as screeners need to be in front of the fluoroscopic screen directly in front of the X-ray beam). Also, such fluoroscopic X-ray images cannot be electronically transmitted, stored or retrieved.
December 2012 Aviationsecurityinternational
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