Measurements of chemical sputtering yields of various types of carbon

Measurements of the chemical sputtering during the bombardment of pyrolytic graphite, isotropic carbon and glassy carbon with 0.1-6 keV hydrogen ions habe been made in the temperature range of room temperature to 700sup(o)C. The maximum production rate occurs at 1 keV for the incident energy and 525sup(o)C for the target temperature in all types of carbon. Energy and temperature dependences of chemical sputtering of carbon are not affected by the structures of the carbon. The reason is ascribed to radiation damage of the surface of the carbon. The dose dependence of the methane production rate was influenced by the hydrogen concentration in a target prior to bombardment, but the steady rate was obtained after the target was bombarded with protons at a dose of more than 1 x 1018 H+cm2. (orig.)