2004 Volume 47 Issue 3 Pages 120-123
Electrical breakdown (surface discharge) is one of the most serious problems for developing compact and/or higher voltage insulation in a vacuum. High secondary electron emission (SEE) yields result in the multipactor (electron multiplication on the dielectric surface). 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 with a scanning electron microscope (SEM) by pulsed-beam method. In order to examine the surface charging, multi-pulse methods are also carried out for the sapphire disk at high temperature.
