1. Department of Low Temperature Physics, Faculty of Mathematics and Physics, Charles University in Prague, V Holešovičkách 2, 180 00 Prague, Czech Republic
2. Institute of Inorganic Chemistry AS CR, v. v. i., 250 68 Husinec-Řež 1001, Czech Republic
3. Department of Nuclear Reactors, Faculty of Nuclear Science and Physical Engineering, Czech Technical University in Prague, V Holešovičkách 2, 180 00 Prague 8, Czech Republic
4. Institute of Laboratory Research on Geomaterials, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina, 842 15 Bratislava, Slovakia
5. Faculty of Electrical Engineering and Information Technology, Institute of Nuclear and Physical Engineering, Slovak University of Technology in Bratislava, Ilkovičova 3, 812 19 Bratislava, Slovakia