Hydrogen isotopic effects on the chemical erosion of graphite induced by ion irradiation

This theoretical study investigates the dynamic behavior of chemical erosion of graphite due to hydrogen-isotope-ion bombardment. Ion energies range from 10 to 1000 eV and target temperatures range from 300 to 1100 K. The computer code employed was TRIDYN. The chemical erosion processes under investigation included surface-related and thermally activated hydrocarbon emission processes. The proposed simulation model of this study was fitted to actual measurements by implementing surface-related and thermally activated coefficients. In addition, the proposed simulation model of this study was improved over our previous model by incorporating a depth-dependent probability for out-diffusion of hydrocarbons. The local reduction of carbon density due to either physical sputtering or chemical erosion was also taken into consideration. Furthermore, application of the proposed simulation model of this study was extended to include all hydrogen isotope ions (i.e. hydrogen, deuterium, and tritium). It was found that all the calculated, fitted, and measured results are in good agreement. In particular, the results calculated from the proposed simulation model of this study surpass previous ones in the low ion energy region in which chemical erosion is of vital importance.