Erosion of beryllium and deposition of carbon and oxygen due to bombardment with C+ and CO+ ions

The bombardment of clean, metallic beryllium with carbon and the co-bombard ment with carbon and oxygen is investigated experimentally and by computer simulation. The experiments use C+ and CO+ ions with energies between 3 and 12 keV at normal incidence. The simulation is carried out with the Monte C arlo code TRIDYN. The results of carbon bombardment from experiment and sim ulation agree well and show the buildup of a carbon adlayer on the metal su rface. After the carbon adlayer formation, no more Be is eroded. For C and O co-bombardment, carried out by CO+ ion bombardment, simulation and experi ment agree for low fluences. At higher fluences, another erosion channel be sides kinematic sputtering is opened by the chemical interactions of C and O. This leads to a deposition/erosion equilibrium which is not predicted by the kinematic TRIDYN code. The formation of a ternary mixture layer on the Be target leads to a continuous erosion of the beryllium target. (C) 1999 Elsevier Science B.V. All rights reserved.