Electron source based on the carbon foil field emission cathode

In this paper studies are conducted on samples made of carbon foil. Emitting surface of the cathode is the edge strips. The cathode material was irradiated with surface emitting linearly polarized radiation from a pulsed YAG:Nd³⁺ laser (λ = 1064 nm). The laser beam is directed normal to the end of the cathode. SEM images analysis showed that after laser treatment the foil segments have orthogonal orientation to the cathode operating surface. Laser treated cathodes showed more stable characteristics with lower fluctuations than non-treated ones.Pulse mode tests of the emitter in diode construction showed that it can give emission current density of more than 26 mA/cm (pulse length 5 μs). Long term tests showed carbon foil operating durability in the conditions of technical vacuum. High current loads tests were held in pulse mode with current amplitude up to 15 mA. Initial and final current-voltage characteristics comparison showed stability of the cathode to high emission current.