A rapid technique for the determination of secondary electron emission yield from complex surfaces

Abstract

Plasma-wall interaction in the presence of secondary electron emission (SEE) can lead to a degradation and reduction in the performance of plasma devices. Materials with complex surface architectures such as velvet, fuzz, and feathered surfaces have a lower SEE yield than the same materials with a flat surface and can, therefore, be useful for plasma applications. This reduction in the SEE is due to the trapping of secondary electrons in the microcavities formed by complex surfaces. In this paper, we present a rapid method for a simultaneous comparison of the SEE yield and surface properties of materials with different surface architectures. The method uses Scanning Electron Microscopy to simultaneously evaluate the surface morphologies and SEE yield properties for a microarchitectured surface. This technique was applied to carbon velvets, and results show agreement with recent theoretical models and with the direct determination of the SEE yield from measurements of the currents of the primary electrons impinging the surface and of the secondary electrons emitted from the surface.