Measurements of Field Electron Emission Sites Distribution for Oxygen Free Copper Electrodes and Microscopic Observations of Emission Sites

Abstract

Electron emission is one of causes leading to electrical breakdown in vacuum. Distributions of field emission sites on a plane electrode before and after current conditioning procedure were investigated by using an Electron Emission Microscope. After the investigation of emission sites distribution, microscopic observation on some of the emission sites were carried out by using an Electron Emission Microscope. The observation revealed that field emission occurs at the foreign particles embedded on the electrode surface. To characterize the emission sites, we observed the absorption current image and analyzed the chemical composition of the emission sites by using an auger electron spectrometer. Observation and analysis suggest that the foreign particle was a semiconducting or insulating material composed of carbon.