We have studied the effect of geometrical and physical parameters of additional lower healer on thermal conditions during BGO growth by the Czochralski technique, in particular, on keeping flat melt/crystal interface during the whole growth process. Numerical simulation by CGSim software was used as an efficient tool for the analysis. After revealing optimal growth conditions and hot zone design by modeling, we have modified experimental growth setup and successfully improved crystal growth process in close agreement to modeling predictions. (C) 2014 Elsevier B.V. All rights reserved.