Understanding the role of carbon in active trap centre formation in porous alumina for ion beam dosimetry

In recent days, due to increased use of hadron therapy for cancer and tumor treatment, precise online dose monitoring is an important issue for safety purpose. Regarding hadron therapy, recently carbon ion beam with high Linear Energy Transfer (LET) is found to be more effective than the photon beams. Among several known TL/OSL oxides phosphors, C-doped alumina (Al₂O₃) is favorable for radiation dosimetry, especially in medical field due to its tissue equivalent in terms of radiation absorption, simple glow curve, and high sensitivity. A facile approach to improve thermoluminescence sensitivity of electrochemically anodized porous Al₂O₃ (AAO) is presented by introducing carbon ions for ion beam dosimetry. Initially, ion implantation technique has been carried out for Carbon doping in AAO in controlled manner. HAADF-STEM, EDS mapping, SEM studies reveal the evolution of a porous structure followed by the carbon distribution up to 200 nm. However, the evolution of optically active F⁺ centres with increasing ion fluence has been examined by photoluminescence investigation at room temperature and thermoluminescence (TL) measurement while the chemical nature of such defect centres has been extracted by depth dependent XPS analysis.