1. Nuclear Physics Institute of the Czech Academy of Sciences, Řež 250 68, Czech Republic
2. Department of Physics, Faculty of Science, J. E. Purkinje University, Ceske Mladeze 8, Usti nad Labem 400 96, Czech Republic
3. Institute of Applied Physics, National Academy of Sciences of Ukraine, Sumy 40030, Ukraine
4. Institute for Nuclear Research, Hungarian Academy of Sciences (MTA Atomki), Bem tér 18/c, Debrecen H-4026, Hungary