Speakers
Description
Understanding the radiation effects at the microscale is essential for advancing cancer treatment strategies such as hadron therapy, which requires new developments in dosimetry to accurately map the cell-level energy distribution and assess the contribution from secondary particles. Herein, luminescence-based dosimetry has gained increasing attention. Thermoluminescence (TL) and optically stimulated luminescence (OSL) detectors offer high low-dose sensitivity, while Fluorescent Nuclear Track Detectors (FNTDs) provide unparalleled spatial resolution for visualizing individual charged-particle tracks. Developing cost-effective materials that combine these capabilities is of interest for radiobiology.
This study investigates the production of Al2O3-based detectors for luminescence dosimetry and particle-track detection. α-Al2O3 single crystals were grown by the flux method, using a Li2O-MoO3 flux, a low-cost synthesis method. The radiation-induced luminescence and dosimetric response (30 mGy – 15 Gy) to 90Sr/90Y β-radiation were studied as a function of precursor purity and intentional doping.
Increasing MoO3 precursor purity (from 99.0% to 99.95%) led to a marked increase in TL/OSL intensity and improved low-dose sensitivity. Standard C and {C,Mg} doping along with novel dopant combinations {C,Zn}, {C,Ti}, {C,Mn}, {C,Ce} and {C,Si} were explored. Doping improved luminescence performance, with {C,Ti} and {C,Mg} yielding the strongest TL/OSL responses, with more than a twofold TL and fourfold OSL increase relative to undoped crystals. These compositions are promising candidates for further studies.
The potential of the crystals as FNTDs was assessed through 12C-ion irradiation experiments conducted at the Heidelberg Ion Beam Therapy Center (HIT, Germany). Both undoped and {C,Mg}-doped crystals exhibited visible ion tracks, suggesting possible application despite lower sensitivity compared to commercial Czochralski-grown FNTDs. Although {C,Mg} doping significantly enhanced TL/OSL intensity, only a modest improvement in the track detection efficiency was observed, with ~50% detection of expected tracks. With further refinement of growth conditions, flux-grown Al2O3 may represent an economically advantageous alternative for luminescence dosimetry and heavy-ion detection.