A.A. Grechnikov - Ph.D. (Chem.), Head of Laboratory, «Energomashtekhnika» (Moscow, Russia); Vernadsky Institute of Geochemistry and Analytical Chemistry of Russian Academy of Sciences (Moscow, Russia). E-mail: agrech@bk.ru A.S. Borodkov - Research Scientist, «Energomashtekhnika» (Moscow, Russia); Vernadsky Institute of Geo-chemistry and Analytical Chemistry of Russian Academy of Sciences (Moscow, Russia). E-mail: ab-ors@mail.ru S.M. Nikiforov - Senior Research Scientist, A.M. Prokhorov General Physics Institute of Russian Academy of Sciences (Moscow, Russia). E-mail: 15925@mail.ru I.I. Kuzmin - Junior Research Scientist, «Energomashtekhnika» (Moscow, Russia); Vernadsky Institute of Geochemistry and Analytical Chemistry of Russian Academy of Sciences (Moscow, Russia). E-mail: mcla-ren.ilya@gmail.com