[1] Ist Nazl Fis Nucl, Lab Nazl Sud, I-95123 Catania, Italy
[2] Ist Nazl Fis Nucl, Sez Catania, I-95129 Catania, Italy
[3] Univ Catania, Dipartmento Fis, I-95129 Catania, Italy
[4] Ist Nazl Fis Nucl, Grp Coll Messina, Messina, Italy
[5] Univ Messina, Dipartimento Fis, I-98100 Messina, Italy
[6] Ist Nazl Fis Nucl, Sez Bari, I-70126 Bari, Italy
[7] Univ Bari, Dipartmento Fis, Bari, Italy
[8] Ist Nazl Fis Nucl, Sez Roma 1, Rome, Italy
[9] Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy
[10] Ist Nazl Fis Nucl, Sez Genova, I-16146 Genoa, Italy
[11] Univ Genoa, Dipartimento Fis, Genoa, Italy
[12] CNR, ISMAR, Sez Venezia, Venice, Italy
[13] Ist Nazl Fis Nucl, Sez Bologna, I-40126 Bologna, Italy
[14] Univ Bologna, Dipartmento Fis, Bologna, Italy
[15] Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy
[16] Ist Nazl Fis Nucl, Sez Cagliari, Cagliari, Italy
[17] Univ Cagliari, Dipartimento Fis, Cagliari, Italy
[18] CNR, IAMC, Messina, Italy
[19] OGS, Sgonico, TS, Italy