[1] Politecn Torino, Dipartimento Energia, NEMO Grp, I-10129 Turin, Italy
[2] Politecn Milan, Dipartimento Elettron Informat & Bioingn, I-20133 Milan, Italy
[3] EUROfus Consortium, PPPT Dept, D-85748 Garching, Germany
[4] ENEA CR Brasimone, I-40032 Catnugnano, Italy