FIELD EMISSION ELECTRON SOURCE

摘要

PROBLEM TO BE SOLVED: To provide a field emission electron source which can provide high electric current density. SOLUTION: An intense electric field is converged into tip end parts 3 and electrons are emitted out of the cathode tip end parts 3 due to the field effect by applying positive voltage to a second electrode layer 6 relative to a first electrode layer 2. The electron emitted out of the cathode tip end parts 3 are accelerated and come into collision against a mesh electrode 7 by applying higher voltage to the mesh electrode 7 than that applied to a gate electrode 6. At that time, secondary electrons in the number more than that of primary electrons are emitted out of the mesh electrode 7 made of a metal and the secondary electrons amplified and emitted by the mesh electrode 7 arrive at an anode 8 to which further higher voltage is applied.