An ultra-high–resolution X-ray machine that fits in a suitcase
Despite its major contributions to imaging of materials and medical diagnostics, X-ray technology has changed very little since the discovery of X-ray radiation over 100 years ago. Conventional thermionic emission relies on the heating of a metal filament (cathode) to over 1 000 degrees Celsius, at which point it emits electrons. These are accelerated to bombard a metal target (anode) that releases X-rays. Electron field emission is under intense investigation for its potential to provide the first major advance in X-ray technology practically since it was invented. Field emission, also called cold emission, is induced by the application of a strong electric field. It has important advantages over thermionic emission, including high current and instantaneous modulation. However, application has been limited due to a lack of reliable, high-performance electron emitters. Carbon nanotubes (CNTs) just may be the cold cathode for which researchers have been searching. Scientists developed a small, portable X-ray device exploiting CNTs synthesised in various architectures with EU funding of the project 'Development of a X-ray tube based on the field emission properties of carbon nanotubes' (NANORAY). The system boasts a highly reduced focal spot for superior image resolution far beyond the current state of the art. The field emission cathode imparts the system with minimal energy consumption, significantly reduced maintenance costs and pulsed mode operation in contrast to conventional thermionic cathodes. The NANORAY system is a cost-effective, portable, ultra-high–resolution X-ray device. Commercialisation will make a tremendous impact on medical diagnostic point-of-use services such as at the scene of an accident. In addition, it is expected to be of great interest to market sectors interested in the spectroscopic analysis of materials such as food quality control. High resolution in a small, portable package is likely to attract those interested in security systems for airports and banks as well. Watch the project’s video here.
