The graphics display system comprises a plurality of heads. The process in accordance with the Czochralski method involves bringing about a temperature distribution in the melt in the region of the solidification interface which deviates from rotational symmetry. A gun barrel includes a tubular component made of a cobalt-based superalloy material. Part of the scatter, after specular reflection at the melt surface, passes through the prism, the entrance window and the scanning mirror to the range-finding unit.