1. Department of Cosmic Research; Saint Petersburg State Polytechnic University; Saint Petersburg; 195251; Russia
2. Laboratory of Ion Beam Physics; ETH Zurich; CH-8093; Zurich; Switzerland
3. Department of Environmental Physics; Swiss Federal Institute of Aquatic Science and Technology; CH-8600; Duebendorf; Switzerland
4. Soil Cryology Laboratory, Institute of Physicochemical and Biological Problems in Soil Science; Russian Academy of Sciences; Pushchino; 142290; Russia
5. Department of Periglacial Research; Alfred Wegener Institute for Polar and Marine Research; Telegrafenberg A43,; D-14473; Potsdam; Germany
6. Laboratory of Quaternary Deposits, Geological Institute; Russian Academy of Sciences; Moscow; 119017; Russia