1. Institute of Experimental Physics, University of Białystok, 41 Lipowa str. 15-424 Białystok, Poland
2. The Sołtan Institute of Nuclear Studies, 05-400 Otwock-Świerk, Poland and Laboratoire de Mineralogie et Cristallographie, Universite de Paris 6 Pierre et Marie Curie, 4. pl. Jussieu, 75252 Paris, France