1. Institute of Electrical Engineering, SAS, Bratislava, Slovakia
2. Institute of Technical Physics, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Riga, Latvia
3. Istituto Nazionale di Fisica Nucleare, Legnaro, Italy
4. ASTeC STFC Daresbury Laboratory, Warrington, U.K.
5. Institute of Materials Engineering, University of Siegen, Siegen, Germany