[1] IMEC, B-3001 Louvain, Belgium
[2] Kumamoto Natl Coll Technol, LT-2054 Vilnius, Lithuania
[3] Japan Atom Energy Res Inst, Takasaki Radiat Chem Res Estab, Gunma 37012, Japan
[4] Rossendorf Inc, Forschungszentrum Rossendorf EV, Inst Ionenstrahlphys & Mat Forsch, D-01314 Dresden, Germany