Spectroscopic study of plasma-facing graphite tiles modified by electron and proton irradiation

Highlights: ► Raman, ESR, and XPS measurements on electron- and proton-irradiated graphite tiles. ► Increase in local order was observed in electron-irradiated sample. ► Structural disorder and amorphization in proton-irradiated sample. ► A narrow ESR peak attributed to localized spins was detected in proton-irradiated sample. - Abstract: We have carried out Raman, electron spin resonance (ESR), and X-ray photoemission (XPS) spectroscopy measurements on the graphite tiles modified by electron and proton irradiation. While increase in local order was observed in the electron-irradiated sample, structural disorder and amorphization were revealed in the proton-irradiated sample, with much reduced electrical conductivity. Besides, a narrow ESR peak attributed to localized spins, closely associated with C–OH bonds as identified by the XPS measurements, was detected in the proton-irradiated sample.