abstract:A field emission gun is a type of electron gun in which a sharply-pointed Müller-type emitter is held at several kilovolts negative potential relative to a nearby electrode, so that there is sufficient potential gradient at the emitter surface to cause field electron emission. Emitters are either of cold-cathode type, usually made of single crystal tungsten sharpened to a tip radius of about 100 nm, or of the Schottky type, in which thermionic emission is enhanced by barrier lowering in the presence of a high electric field.
The morphologyandcrystallography analysis oflathmartensitewithinapacketin17CrNiMo6steelwas studied by electronbackscatteringdiffraction(EBSD) withfield emission gun.