Deuterium bombardment of carbon and carbon layers on titanium

Interaction of deuterium ions with highly oriented pyrolytic graphite and thin carbon layers on titanium are studied by X-ray photoelectron spectroscopy (XPS) measurements. The effects induced by the deuterium beam are compared to bombardment with chemically inert argon ions. XPS allows the identification of several carbon states: graphitic carbon, disordered graphitic carbon, ion-induced radiation defects in carbon, and carbidic carbon in the carbon films on titanium. Erosion of the carbon film by deuterium proceeds through two paths: first a chemical erosion with a cross-section of 4.7x10-17 cm2 removes elementary carbon. At the same time, carbidic carbon is eroded with a linear yield of 0.003 within the fluence range between 8x1016 and 1.4x1017 cm-2