In this video we see an electron gun made of many thousands of vertically aligned carbon nanotubes, each more than 1,000 times smaller than the width of a human hair. Dr Matt Cole explains the technological importance of exploiting emerging nanomaterials to engineer functionally novel X-ray sources.

Electron guns are central to almost all commercial X-ray sources

Matt Cole

"Thanks to recent progress in nanomaterials growth we can now engineer materials at the scale of individual atoms.

This image, taken with an electron microscope, shows a nanoengineered electron gun formed from many carbon nanotubes that have been grown to be vertically aligned.
Electron guns are central to almost all commercial X-ray sources. They may be found in border control, food and pharmaceuticals inspection, electronics validation and medical diagnostics. Despite being so widespread, most systems use emitters that are inefficient because they have to be run at high temperatures.

Patterned by a process called high resolution electron beam lithography, carbon nanotubes are made of rolled and concentrically nested graphite; where each tube is over one thousand times smaller than a human hair.

More than a century old, bombardment-based X-ray sources have experienced little technological development. The use of one and two-dimensional nanomaterials - such as nanotubes, nanowires and single-atom thick graphene-like materials - have the potential to modernise this stagnated technology by producing longer lasting, increasingly stable emitters. In the future, these advanced emitters will facilitate the emergence of a host of new X-ray technologies such as micro-cancer treatment, high-throughput roll-to-roll manufacturing, and real-time three-dimensional imaging."

'Nanomaterials Up Close' is a special series linked to our 'Under the Microscope' collection of videos produced by Cambridge University that show glimpses of the natural and man-made world in stunning close-up.

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