Patent ID: 6617597
Filing Date: 2003-09-09
Classification: B82Y,G11B,H01J

Abstract:
A method for controlling the energy in an electron beam, comprising:providing an emitter at a predetermined first voltage, a surface of the emitter defining a first boundary of a gap; arranging a target surface disposed from the emitter, the target surface having a predetermined second voltage, the target surface defining a second boundary of the gap, wherein the gap is designated for traversal by the electronic beam; introducing an extractor at a controllable third voltage, the extractor at least partially disposed within the gap, wherein the controllable third voltage falls between the first and second voltages and wherein the controllable third voltage induces electrons to exit the emitter by driving an input current having a magnitude equivalent to the current magnitude desired in the electron beam; estimating the actual electron beam energy by sensing the emitter current; and adjusting the third voltage in response to the sensed emitter current.