Enhanced Scintillation with Uncorrelated TL and OSL Signals in LiCaAlF ₆ :Eu Nanoparticles Enables Unprecedented Multimodal Radiation Dosimetry

Abstract The development of multimodal dosimeters capable of preserving independent luminescent signals is a transformative goal in radiation sensing. Here, Eu‐doped LiCaAlF 6 nanoparticles (NPs) are synthesized via a hydrothermal route. The synthesis parameters are systematically optimized. XRD confirmed single‐phase formation at low Eu concentrations. Spectroscopic analyses (XPS, PL, and time‐resolved emission) verified the predominance of Eu 2+ ions, responsible for the intense blue emission under X‐ray excitation. Dosimetric performance is assessed by radioluminescence (RL), thermoluminescence (TL), and optically stimulated luminescence (OSL). RL results revealed a relationship between Eu‐doping concentration and x‐ray fluence, suggesting that samples with higher %Eu are better suited for applications involving elevated photon fluence, such as flash radiotherapy. Samples with the smallest crystallite size exhibited the highest TL and OSL intensity and sensitivity. NPs doped with 0.1 mol% Eu and synthesized with PVP exhibited superior sensitivity and linear dose‐response, achieving minimum detectable doses of 4.7 mGy (TL) and 8 mGy (OSL). These samples demonstrated unprecedented behavior, maintaining intense TL signals even after complete OSL readout, thereby revealing uncorrelated TL and OSL processes within the same material system. This unique characteristic allows sequential and non‐destructive dose assessments, enabling the development of versatile, multimodal radiation detection platforms.