[1] INFN, Sez Padova, Via Marzolo 8, I-35131 Padua, Italy
[2] INAF Osservatorio Astron Abruzzo, Via Mentore Maggini, I-64100 Teramo, Italy
[3] INFN, Lab Nazl Gran Sasso, Via G Acitelli 22, I-67100 Laquila, Italy
[4] Univ Genoa, Dipartimento Fis, Via Dodecaneso 33, I-16146 Genoa, Italy
[5] INFN, Sez Genova, Via Dodecaneso 33, I-16146 Genoa, Italy
[6] INFN, Lab Nazl Legnaro, Viale Univ 2, I-35020 Legnaro, Italy
[7] INFN, Sez Milano, Via Celoria 16, I-20133 Milan, Italy
[8] Univ Bari, Dipartimento Interateneo Fis M Merlin, Via G Amendola 173, I-70126 Bari, Italy
[9] INFN, Sez Bari, Via E Orabona 4, I-70125 Bari, Italy
[10] Politecn Torino, Dipartimento DISAT, Corso Duca Abruzzi 24, I-10129 Turin, Italy
[11] INFN, Sez Torino, Via P Ciuria 1, I-10125 Turin, Italy
[12] INFN, Sez Catania, Via Santa Sofia 64, I-95123 Catania, Italy
[13] INFN, Sez Ferrara, Via Saragat 1, I-44122 Ferrara, Italy
[14] INFN, Lab Nazl Sud, Via Santa Sofia 62, I-95123 Catania, Italy
[15] INFN, Sez Perugia, Via A Pascoli, I-06123 Perugia, Italy
[16] INFN, Lab Nazl Frascati, Via E Fermi 40, I-00044 Frascati, Italy
[17] INFN, Sez Napoli, Via Cinthia, I-80126 Naples, Italy
[18] Univ Napoli Federico II, Dipartimento Fis E Pancini, Via Cinthia 21, I-80126 Naples, Italy
[19] Univ Trieste, Dipartimento Fis, Via A Valerio 2, I-34172 Trieste, Italy
[20] INFN, Sez Trieste, Via A Valerio 2, I-34172 Trieste, Italy
[21] Univ Milan, Dipartimento Fis, Via Celoria 16, I-20133 Milan, Italy
[22] INFN, Sez Bologna, Viale C Berti Pichat 6-2, I-40127 Bologna, Italy
[23] Univ Bologna, Dipartimento Fis & Astron, Viale C Berti Pichat 6-2, I-40127 Bologna, Italy
[24] ENEA Bologna, Via Martini di Monte Sole 4, I-40129 Bologna, Italy
[25] Univ Padua, Dipartimento Fis & Astron, Via Marzolo 8, I-35131 Padua, Italy
[26] Univ Perugia, Dipartimento Fis & Geol, Via A Pascoli, I-06123 Perugia, Italy
[27] Univ Catania, Dipartimento Fis & Astron, Via Santa Sofia 64, I-95123 Catania, Italy
[28] INFN, Sez Roma, Ple Aldo Moro 2, I-00185 Rome, Italy