X-ray sources with carbon field emitter cathodes

X-ray radiation is widely used in medical, industrial and research applications. New developments in X-ray optics and detectors opened possibilities to reduce the necessary source intensities by at least 2 orders of magnitude to obtain similar results in comparable times. In consequence a new generation of compact low power micro-focus X-ray tubes is required. The substitution of thermionic cathodes by field emitters offer means to reduce the size and power demand of miniature X-ray sources. Therefore, carbon fibre and carbon nanotube (CNT) field emitters have been investigated in a recent research project as promising electron sources for miniature X-ray tubes. We discuss the influence of electron-source design parameters on X-ray properties, in dependence on different carbon field emitter types. Finally, a comparison between low-power X-ray devices with thermionic and with carbon field emitter cathodes is given.