Erosion of CFC under simultaneous bombardment by helium and deuterium ions

The erosion of 1D-CFC due to the simultaneous bombardment of He+, D3+, D2+ and D+ ions with the known fluxes of the each species has been studied as a function of the φHe/φD flux ratio with sample temperature of 450, 773 and 973 K. It has been commonly observed that for the low energy chemically active species for which the damage production rate is not saturated (<300 eV) the addition of a second energetic species should lead to an increase in the hydrocarbon release rate. However, a mechanism leading to the hydrocarbons molecule/precursor breakup can actually result in a decrease in the erosion yield. The balance between these two processes is a complicated function of flux ratio, projectile energies and concentration. Up to now there are no data available for the case when the energies of both species are not enough for the damage production rate saturation. At the present experiments the energy of deuterium was from 67 eV/deuteron for D3+ ions to 200 eV/deuteron for D+ ions and the energy of He+ ions was 200 eV. The analytical description of the graphite erosion by hydrogen ions from J. Nucl. Mater. 266–269 (1999) 51 was applied to describe the present experimental data.