Bi-crystal silicon ingots with coincident site lattice (CSL) grain boundaries (GB), namely Sigma 3, Sigma 9, Sigma 27a, have been grown in a small scale Bridgman type furnace at 3 mu/s. Melts have been intentionally polluted with 25 ppma of copper and indium. Segregation of these impurities towards the central grain boundaries has been assessed by secondary ion mass spectrometry (SIMS). Influence of topological imperfections and grain boundary nature has been investigated. While copper segregation towards Sigma 3 GB has not been detected, copper has been found to diffuse towards Sigma 9 and Sigma 27a GB, especially at steps and GB junctions. Indium segregation has not been detected at any GB. This indicates that slow-diffusing element segregation towards GB depends on the boundary nature, and/or the grains orientation. (C) 2015 Elsevier B.V. All rights reserved.