1. Faculty of Electronic Engineering, University of Niš, Aleksandra Medvedeva 14, 18000 Niš, Serbia
2. Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade-Zemun, Serbia
3. Vinča Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade, Serbia
4. Institute for Multidisciplinary Research, University of Belgrade, P.O. Box 33, 11030 Belgrade, Serbia
5. Institut Pprime CNRS, Université de Poitiers-ENSMA, 2 Rue Pierre Brousse, Bâtiment B25, TSA 41105, 86073 Poitiers Cedex 9, France