[1] Ist Nazl Fis Nucl, Sez Padova, Grp Collegato Trento, I-38050 Trento, Italy
[2] Univ Perugia, I-06123 Perugia, Italy
[3] Ist Nazl Fis Nucl, Sez Perugia, I-06123 Perugia, Italy
[4] ITC, IRST, Div Microsistemi, I-38050 Trento, Italy
[5] Scuola Normale Super Pisa, I-56127 Pisa, Italy
[6] Ist Nazl Fis Nucl, Sez Pisa, I-56127 Pisa, Italy
[7] Politecn Bari, DEE, I-70125 Bari, Italy
[8] Ist Nazl Fis Nucl, Sez Bari, I-70125 Bari, Italy
[9] Univ Trent, Dipartimento Informat & Telecomunicaz, I-38050 Trento, Italy
[10] Dipartimento Fis E Fermi, I-56127 Pisa, Italy
[11] Ist Nazl Fis Nucl, Sez Pisa, I-56127 Pisa, Italy
[12] Dipartimento Fis, I-40127 Bologna, Italy
[13] Ist Nazl Fis Nucl, Sez Bologna, I-40127 Bologna, Italy
[14] Ctr Studi & Ric Enrico Fermi, I-00184 Rome, Italy