1. Department
of Polymer Engineering and Science, Montanuniversität, Otto-Glöckel Straβe
2, 8700 Leoben, Austria
2. LNESS,
Department of Physics, Politecnico di Milano, via Anzani 42, 22100 Como, Italy
3. Istituto Nazionale
di Fisica Nucleare, via Celoria 16, 20133 Milano, Italy
4. Eni Donegani Research
Center for Renewable Energies and Environment, Via Fauser 4, 28100 Novara, Italy
5. Institute
of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner
Landstraße 400, 01328 Dresden, Germany
6. Institut
für Physik, Martin-Luther-Universität Halle, 06099 Halle, Germany
7. Department
of Aerospace Science and Technology, Politecnico di Milano, via La Masa
34, 20156 Milano, Italy