1. National Institute of Nuclear Physics (INFN), Via B. Rossi, 1-3, 50019 Sesto Fiorentino (FI), Italy
2. Department of Physics and Astronomy, University of Florence, Via G. Sansone 1, 50019 Sesto Fiorentino (FI), Italy
3. European Laboratory for Non-Linear Spectroscopy, Via Nello Carrara 1, 50019 Sesto Fiorentino (FI), Italy
4. Istituto Nazionale di Ottica (INO-CNR), Largo Enrico Fermi 6, 50125 Firenze (FI), Italy
5. Jozef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia
6. National Institute of Nuclear Physics (INFN), Via A. Pascoli, 06123 Perugia (PG), Italy
7. Department of Physics, University of Perugia, Via A. Pascoli, 06123 Perugia (PG), Italy
8. Department of Engineering, University of Perugia, Via G. Duranti 93, 06125 Perugia (PG), Italy
9. GSI Helmholtzzentrum für Schwerionenforschung, Planckstraße 1, 64291 Darmstadt, Germany