Deuterium Retention in Tungsten Mixed Carbon Dust

Abstract

Tungsten mixed carbon dust was prepared using a deuterium arc plasma discharge with tungsten and carbon electrodes. The concentration of tungsten with an atomic ratio of W/(C+W) was in the range from 0 to 0.3. The Raman spectra showed that the crystal structure of carbon became amorphous with the addition of tungsten, although two broad peaks owing to graphite and defective graphite appeared. The structure also became amorphous when the substrate temperature decreased. The retained deuterium desorbed mainly at approximately 900 K, which corresponds to the desorption of deuterium trapped by carbon atoms. Namely, most of the co-deposited deuterium is retained in the carbon atoms. The amount of retained deuterium increased with an increase in the tungsten concentration. The amount of retained deuterium was larger than that of the co-deposited carbon dust which was similarly prepared in the arc plasma discharge with only carbon electrodes. The increase in deuterium retention is due to the enhanced amorphous structure by the mixture of tungsten.