EFFECTS OF HIGHLY CHARGED IONS ON COATED GLASSY CARBON

Abstract

The damage induced on glassy carbon coated with thin films of tungsten by slow, but highly charged ion, the Xe⁴⁰⁺ of three different fluences and energies was studied and analysed. The pristine and irradiated glassy carbon coated with tungsten films were characterized at room temperature by Raman spectroscopy and atomic force microscopy. Raman results showed that the virgin glassy carbon has a crystalline size of 2.91 nm. This parameter was found to has reduce in size due to increase in disorder introduced by the HCI irradiation. The observed trends associated with irradiation, viz I_D/I_G reduction, upwards shift in D peaks, downwards shift in G peaks and increment in full width at half maximum FWHM in the HCI irradiated samples compared to the same parameters for the pristine glassy carbon, are signs of increase in the amount of disorder, which shows increase in the sp³ content and bond-angle distortion induced by HCI irradiation on the same type of glassy carbon. This shows that W films play a shielding role, hence the glassy carbon structure suffers less disorder due HCI bombardment. Samples irradiated with high kinetic energy of 460 keV has the least crystalline size of 1.54 nm. This shows that the energy of HCI contributes substantially to damage introduced in the glassy carbon. The AFM results concur with the Raman results. The hillock size and surface roughness are most visible in the irradiated sample with largest energy of 460 keV. Glassy carbon enhanced with tungsten coatings could find applications in nuclear technology, especially for containment of dry nuclear waste.