1. Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw, Poland
2. Department of Mathematics and Natural Sciences, College of Science, Cardinal S. Wyszyński University, Dewajtis 5, 01-185 Warsaw, Poland
3. National Technical University KPI, 21 Frunze Street, 61002 Kharkov, Ukraine
4. Institute for Scintillation Materials, NASU, Lenin Ave. 60, 61001 Kharkov, Ukraine