Field emission from carbon fibres

Abstract

The development is described of a carbon-fibre field-emission source with a brightness of 1012 A sr−1 m−2 and currents in excess of 200 μA sr−1 at voltages of 2-3 kV. The source can be run continuously in ambient gas pressures two decades higher than tungsten field emitters at the same current fluctuation level of 2-3%. The source makes possible the operation of field-emission electron guns in conventional unbaked vacuum systems.