[1] Multicharged Ions Spectra Data Ctr, Mendeleevo 141570, Russia
[2] Univ Milan, Dipartimento Fis, Milano, Italy
[3] Rutherford Appleton Lab, Chilton, Oxon, England
[4] Ecole Polytech, LULI, F-91128 Palaiseau, France
[5] ENEA, CRE, Dipartimento Innovaz, Frascati, Italy
[6] Univ Aquila, Dipartimento Fis, I-67100 Laquila, Italy
[7] Univ Modena, Dipartimento Fis, I-41100 Modena, Italy