Raman measurements in silica glasses irradiated with energetic ions

Abstract : Energetic He+(2.5MeV), O4+(13.5MeV), Si4+(24.4MeV) and Cu7+ (32.6MeV) ion implantations at different fluences (from 5x1012 to 1.65x1015 ions/cm2) were performed in three types of SiO2 glasses with different OH content (KU1, KS-4V and Infrasil 301). After ion implantation the Raman spectra were measured and compared with the spectra of unirradiated samples. Irradiated samples of the three silica grades exhibit changes in the broad and asymmetric R-band (~445 cm-1) and in D1 (~491cm-1) and D2 (~605 cm-1) bands associated to small-membered rings, these bands for different ions show an increase with increasing deposited energy and fluences, indicating structural changes. Macroscopic surface cracking was detected for all the implanted species, mainly at fluences corresponding to deposited energies between 1023 eV/cm3 and 1024 eV/cm3 (after ion beam shutdown).