Carbon deposition on targets during beam bombardment

In nuclear reaction experiments, carbon is usually deposited on the target surface during beam bombardment. This is considered to be caused by the dissociation of the residual hydro-carbon molecules in the vacuum chamber. Even a slight amount of carbon may cause intolerable contamination reactions. To reduce such carbon build-up, it is necessary to understand in more detail the deposition phenomenon. In the present work results of measurements are presented, which describe the carbon build-up on different target materials as a function of beam charge and target thickness. (orig.)