Field Emission Cathodes Fabricated from Bulk Carbon Nanotube Fibers and Films

Carbon Nanotube (CNT) fibers and films have demonstrated excellent field emission (FE) properties and thus hold significant potential for use as electron sources for vacuum electronic devices VEDs). FE cathodes made from 100μm diameter CNT fibers were fabricated on an industrial grade 3D knitting machine. A 1” diameter cathode was tested using 30kV, 30A power supply with a 300ns pulse width. An applied field strength of 3V/μm produced a measured current level of approximately 15A. A CNT film cathode was fabricated from a 20mm wide film arranged in a corrugated geometry. This cathode was tested in a low impedance linear transformer driver (LTD) system operating at 30kV with a 200ns pulse width. The measured current level was approximately 2kA for an applied field strength of 6V/μm.