Carbon nanotube cold cathodes for miniature X-ray tubes

The field emission properties of single-walled carbon nanotubes deposited by chemical vapour deposition on plane substrates and on wires have been investigated. The good emitting performances of the nanotubes are promising for the assembling of robust and efficient cold cathodes, and in particular for the use as an electron source for X-ray production. Tiny electron sources have been fabricated by coating metal wires (W, 300 &mgr;m diameter) with nanotubes. To assess the efficiency of such nanotube-based cathodes for generating X radiation, a prototype X-ray tube has been fabricated. Preliminary measurements of X-ray emission obtained with such a device are presented.