1. Warsaw University of Technology, Institute of Electronic Systems, Nowowiejska 15/19, 00-665 Warsaw,
Poland
2. Institute of Plasma Physics and Laser Microfusion, Hery 23, 01-497 Warsaw, Poland
3. CEA, IRFM, F-13108
Saint-Paul-lez-Durance, France
4. CERN, 1211 Geneva 23,
Switzerland