[1] Univ Camerino, Scuola Sci & Tecnol, I-62032 Camerino, Italy
[2] INFN, Ist Nazl Fis Nucleare, Sez Perugia, Perugia, Italy
[3] Ist Nazl Fis Nucleare, Sez Pisa, Pisa, Italy
[4] Politecn Torino, Dipartimento Elettron & Telecomunicazioni, I-10129 Turin, Italy
[5] Ist Nazl Fis Nucleare, Sez Torino, Turin, Italy
[6] Ist Nazl Fis Nucleare, Sez Milano, I-20133 Milan, Italy
[7] Univ Pavia, Dipartimento Fis, I-27100 Pavia, Italy
[8] Ist Nazl Fis Nucl, Sez Pavia, I-27100 Pavia, Italy
[9] Univ Roma Tor Vergata, Dipartimento Ingn Elettron, I-00133 Rome, Italy
[10] Sez Roma Tor Vergata, Ist Nazl Fis Nucleare, Rome, Italy
[11] Univ Pisa, Dipartimento Ingn Informaz, I-56122 Pisa, Italy
[12] Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy
[13] Univ Modena & Reggio Emilia, Dipartimento Sci Fis Informat & Matemat, Modena, Italy
[14] Consiglio Nazl Ric CNR, Ist Nanosci, Natl Enterprise Nanosci & Nanotechnol NEST, I-56127 Pisa, Italy
[15] Univ Torino, Dipartimento Fis, I-10125 Turin, Italy
[16] Univ Pisa, Dipartimento Fis, I-56127 Pisa, Italy
[17] Univ Milano Bicocca, Dipartimento Fis, I-20126 Milan, Italy
[18] Paul Scherrer Inst 5232, Villigen, Switzerland
[19] Univ Southampton, Optoelect Res Ctr, Southampton SO17 1BJ, Hampshire, England
[20] Univ Pavia, Dipartimento Ingn Industriale & Informaz, Pavia, Italy
[21] Univ Napoli Federico II, Dipartimento Fis E Pancini, Naples, Italy
[22] Univ Roma Tor Vergata, Dipartimento Fis, I-00133 Rome, Italy
[23] Univ Roma Tor Vergata, Dipartimento Ingn Elettron, I-00133 Rome, Italy
[24] Swinburne Univ Technol, Space Technol & Ind Inst, Hawthorn, Vic 3122, Australia
[25] Univ Milano Bicocca, Dipartimento Informat Sistemist & Comunicaz, Milan, Italy