Method and Apparatus for Selectively Providing Electrons in an Ion Source

摘要

An electron source can selectively provide a first stream of electrons that travels in a direction along an imaginary line to a location remote from the electron source, or a second stream of electrons that travels in the direction along the line to the location. The electron source includes a first electron emitter for selectively emitting electrons for the first stream, and a second electron emitter for selectively emitting electrons for the second stream. A different aspect relates to a method for operating an apparatus having an electron source that includes first and second electron emitters. The method includes selectively producing a first stream of electrons that travels from the first electron emitter in a direction along an imaginary line to a location remote from the electron source, or a second stream of electrons that travels from the second electron emitter in the direction along the line to the location.