Optically Stimulated Nanodosimeters with High Storage Capacity.

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Thermoluminescence (TL) and optically stimulated luminescence (OSL) are crucial for radiation detection and dosimetry.
• Developing novel phosphors with enhanced properties is essential for advancing these fields.
• Nanophosphors offer unique advantages due to their high surface area and tunable properties.

Purpose of the Study:

• To investigate the thermoluminescence (TL) and optically stimulated luminescence (OSL) properties of β-Na(Gd,Lu)F₄:Tb³⁺ nanophosphors.
• To evaluate their potential for applications in radiation dosimetry, particularly in medical settings.
• To characterize the trap dynamics and storage capacity of these novel nanophosphors.

Main Methods:

• Synthesis of β-Na(Gd,Lu)F₄:Tb³⁺ nanophosphors using a high-temperature coprecipitation method.
• Irradiation with X-rays to induce radioluminescence and subsequent TL/OSL measurements.
• Optical stimulation using infrared light (808 nm and 980 nm) to empty luminescence traps.
• Characterization of storage capacity and trap depths.

Main Results:

• The nanophosphors exhibit a bright green afterglow detectable for hours after X-ray excitation.
• Exceptional storage capacity of (2.83 ± 0.05) × 10¹⁶ photons/gram, comparable to benchmark bulk phosphors.
• Demonstrated optical emptying of shallow traps using infrared light, while deeper traps require thermal emptying.
• Successful demonstration of OSL at therapeutically relevant radiation doses.

Conclusions:

• β-Na(Gd,Lu)F₄:Tb³⁺ nanophosphors possess excellent luminescence properties, including high storage capacity and afterglow.
• The ability to optically stimulate luminescence offers advantages for specific dosimetry applications.
• These nanophosphors show significant promise for medical dosimetry due to their performance and solution-processability.