Miniature CNT-based FE X-ray sources. (a) A disordered miniature CNT, brazed triode X-ray source fabricated by ball milling, and firing of a CNT paste on the apex of a 0.6 mm Kovar rod, and operated at 12 kV . Copyright 2013, Electronics and Telecommunications Research Institute . Copyright 2013, American Institute of Physics (b) A miniature X-ray source fabricated by thermal CVD capable of supporting current densities of up to 1 A/cm2 . Copyright 2004, Joint Committee on Powder Diffraction Standards. (c) A sintered SWCNT paste transmission-type miniature CNT cathode X-ray source, weighting 14.5 g, and operating up to 70 kV with uniform spatial dose distribution . Copyright 2012, Springer. (d) A 7.5 cm long selaed CNT-based X-ray source operating at 30 kV. . Copyright 2013, Society of Photo-Optical Instrumentation Engineers. (e) An Oxford Instruments X-ray Technology Inc. miniature field emission X-ray tube with gated MWCNT 2 mm diameter cathode. Adapted from . Copyright 2004, Joint Committee on Powder Diffraction Standards.