1. INFN Section of Naples, Complesso Universitario di Monte Sant'Angelo , Via Cintia, I-80126 Napoli, Naples, Italy
2. Department of Electrical Engineering and Information Technology, University of Naples ‘Federico II’ , Via Claudio, 21, I-80125 Napoli, Naples, Italy
3. ESO , Karl-Schwarzschild-Straße 2, D-85748 Garching bei München, Germany
4. Department of Physics ‘Ettore Pancini’, University of Naples ‘Federico II’ , Via Cintia, I-80126 Napoli, Naples, Italy