Influence of Deuterium Retention on Secondary Electron Emission from Graphite under Deuterium Plasma Exposure

Abstract

The influence of deuterium retention on the electron-impact secondary electron emission (SEE) is studied in isotropic graphite (ETU-10). The ETU-10 surface sheath voltage and its deuterium retention under deuterium plasma exposure were measured simultaneously. Deuterium retention was estimated using in situ nuclear reaction analysis. While deuterium retention increased with decreasing graphite sample temperature, the sheath voltage on the sample surface decreased. The sheath potential variation is considered to be due to the SEE yield variation, which was estimated using the sheath voltage. The estimated SEE yield value increased by approximately 10% as the deuterium retention rose by a factor of two.