Investigation on the optically stimulated luminescence properties of KCl: Al3+ under gamma irradiation

Abstract

In order to investigating the suitability of KCl: Al³⁺ as a radiation dosimetry material, KCl: Al³⁺ pellets were prepared by the sintering method and the optically stimulated luminescence (OSL) properties of KCl: Al³⁺ under γ-irradiation were examined. X-ray diffraction analysis demonstrated that the structure of KCl was minimally altered by Al³⁺ doping, and the effective atomic number of the KCl: Al³⁺ pellet is 18.10. In order to obtain the trap depth and distribution in KCl: Al³⁺, the thermoluminescence (TL) curve of the materials was tested with an average activation energy of 1.00 eV for the main luminescence peaks, an average frequency factor of 4.19 × 10¹¹ s⁻¹, and the second order kinetics. In the OSL properties test, the impact of varying doping concentrations and grain sizes on the OSL response was examined. The findings revealed that the KCl: Al³⁺ pellets with a doping concentration of 0.001 mol % and a grain size of 125–150 μm exhibited the best OSL response. Upon excitation with the 520 nm green light pulse OSL (POSL), the minimum detectable dose (MDD) of KCl: Al³⁺ was observed to be 5.31 μGy. Furthermore, a favorable linear dose-response was evident within the dose range of 1–1000 mGy. The test analysis demonstrated that the POSL signal fading of KCl: Al³⁺ was consistent with the multiple traps and centers model. In comparison to pure KCl, the introduction of Al³⁺ resulted in a slower decay of the POSL signal. In the repetitive experiments of the material usage, the coefficient of variation was shown to be stably at 7.00 % in 9 tests. This paper demonstrates that the KCl: Al³⁺ material, with further optimization of its signal fading properties, has the potential for use in personal dosimetry and low-dose measurements, such as those employed in radiation therapy.