Design optimisation of C ion implantation of alpha-Al2O3 for medical dosimetry

Abstract

The present work reports the fabrication and characterization of alpha-Al2O3:C, a highly sensitive low effective atomic number (Z(eff)= 10.7) OSL material for medical dosimetry, through a new approach of doping via implantation. In this study, a Single Crystallinea-Al2O3 (SCALO) and a Sapphire alpha-Al2O3 (SALO) are used and implanted with 100 keV of C+ at various fluences (mol%) from 2.5 x 10(14) ions cm(-2) (similar to 0.04%) to 6.25x 10(15) ions cm(-2) (similar to 1%) and are pre-heated up to 220 degrees C. The structural, optical, morphological and luminescent studies of the Carbon doped a-Al2O3 (alpha-Al2O3:C) are carried out using X-ray diffraction, Ultraviolet-visible spectroscopy (UV-Vis), Photo-luminescence (PL), Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS), Optically Stimulated Luminescence (OSL), and Thermo-Luminescence (TL). The doping of similar to 1 mol% of C+ is found at an optimized doping level due to its high intensity of luminescence. This phenomenon is studied for heavy charged particle (HCP) dosimetry, which might prove effective for cancer treatment. It is found that alpha-ALO:C (both the single crystalline and the sapphire alumina) has the capability to measure large radiation doses (similar to kGy). This is attributed to the generation of stable defects after the incorporation of Carbon that results in a linear response with the dose and in extraordinary efficiency. Thus, this study confirms the development of alpha-Al2O3 by the novel approach of C+ implantation method and the findings result in an efficient medical radiation dosimeter. (C) 2018 Elsevier Ltd. All rights reserved.