Reduction of surface losses of CVD diamond by passivation methods

The high-power long pulse RF loss properties of CVD diamond windows for ECR heating and plasma stabilization in large fusion devices have been measured by established Fabry-Perot methods [1,2,3]. The dielectric loss is strongly influenced by the surface chemistry of the diamond. Special surface passivation techniques are investigated due to the reduction of the electrical surface conductivity and therefore of the RF losses.