1. INFN- National Laboratory of Frascati, Via Enrico Fermi 40, 00044 Roma, Italy
2. Rome International Center for Materials Science Superstripes, Via dei Sabelli 119A, 00185 Roma, Italy
3. University of Firenze, Physics and Astronomy Department, Largo Enrico Fermi 2, 50125 Florence, Italy
4. University of Camerino, Science and Technology
Faculty, Via Madonna delle
Carceri 9, 62032 Camerino, Macerata, Italy
5. Department
of Geological Science, University of Roma Tre, Largo San Leonardo
Murialdo 1, 00146 Roma, Italy
6. IFN- Institute for Photonic and Nanotechnologies, Via Cineto Romano 32, 00156 Rome, Italy
7. CNR-IOM and University of Rome Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy
8. Diamond Materials GmbH, Hans-Bunte-Strasse
19, 79108 Freiburg, Germany