New field emission gun with energy filtering effect

We have developed and tested a new kind of field emission gun. This electron gun is an energy filtering field emission gun that is able to reduce the energy spread of the beam. An energy spread as small as ΔE=0.16 eV full width at half maximum has been measured, at an accelerating voltage V=10 kV, for a probe current Ip=2.1 nA and an illuminating half-angle α=1.2 mrad.