A reliable method for depositing a layer of carbon on the inner walls of a fused silica ampoule is described and characterized. Carbon deposition rates were found to be 0.33 mu m/h at mid-length and range from 0.26 to 0.55 mu m/h at the ends of a 150mm long ampoule. Deposition rate was found to vary along the length of the ampoule, but not along the radial perimeter. (c) 2006 Elsevier B.V. All rights reserved.