Theoretical analysis and experimental verification of scintillator luminescence nonlinearity based on carrier quenching model

Abstract

<sec>The scintillator detector is one of the most important detectors in the field of radiation detection and radiation physics. The characteristics and performance of scintillator that is a core part of the measurement system, are widely studied. Especially, the nonlinearity of scintillators under high excitation density has received more attention because of its direct influence on the measurement results. In this paper, physical modeling and experimental research on this problem are carried out in-depth.</sec><sec>First, the second-order quenching effect of excitons on the scintillator luminescence process is quantitatively analyzed based on the carrier dynamic equation. The luminescence attenuation curves of scintillator under different initial carrier concentrations generated by different excitation densities are obtained. The relationship of the light yield and the efficiency of scintillator with the initial carrier concentration is analyzed, and the results show that with the increase of the initial carrier concentration, the light yield tends to be saturated and the light efficiency decreases. Then CeF₃ scintillator is studied in the Z-scan photoluminescence experiment. The relationship between the light yield and the excitation density is obtained, and the experimental data can be fitted by the carrier quenching model well, which verifies the physical model. At the same time, the energy density threshold corresponding to the 10% nonlinearity of CeF₃ scintillator is obtained.The physical model established in this paper can be used to predict and explain the nonlinear luminescence of various scintillation materials according to different parameters of crystal materials, which is important to understand and solve the nonlinearity problem of scintillators under high excitation density in practical application of radiation detection.</sec>