Secondary electron emission of sapphire and anti-multipactor coatings at high temperature

Abstract

Electrical breakdown (surface discharge) is one of the most serious problems for developing compact and/or higher voltage insulation in a vacuum. Electron multiplication (multipactor) due to high secondary electron emission (SEE) yields from an insulator surface is one of the reasons for the discharge. Multipactor induces not only discharging but also excess surface heating, leading to localized surface melting. Thus, SEE at high temperature is important for understanding the actual breakdown process. The SEE yield of single crystal alumina (sapphire) and anti-multipactor coatings, such as TiN and DLC films having low SEE yields, are measured in a scanning electron microscope (SEM).