基于NaCl:Cu晶体动力学模型的光释光特性数值模拟研究

Numerical Simulation Study of Optically Stimulated Luminescence Characteristics Based on Dynamic Model of NaCl:Cu Crystal

  • 摘要: 目前对NaCl:Cu OSL特性的实验研究在高剂量、长时间尺度和细微过程观察等条件下存在局限性。为准确预测其温度依赖性、衰减性和剂量响应,根据文献实验数据,针对NaCl:Cu动力学模型的能级参数进行了修改,结合电荷跃迁速率微分方程组和R语言数值算法,通过计算每次事件后晶体中电子和空穴中心浓度的变化,模拟NaCl:Cu晶体的OSL特性。结果表明,NaCl:Cu晶体的OSL灵敏度与测量温度之间存在强相关性。将OSL信号衰减的模拟结果与文献中TL信号衰减的实验数据进行定量比较,指出OSL信号表现出衰减和反向衰减现象,但变化范围保持在较小范围内,远小于TL信号的衰减程度。模拟结果表明,NaCl:Cu晶体的剂量响应在0~200 Gy范围内保持线性,在200 Gy时呈饱和趋势。

     

    Abstract: The study on NaCl:Cu as a potential material for dose component alternatives has brought to light its advantageous features, such as a low acquisition cost and remarkable optically stimulated luminescence (OSL) characteristics. Nevertheless, current investigations into NaCl:Cu OSL face certain limitations when it comes to high doses, extended exposure durations, and intricate observations. In order to overcome these challenges and gain a more comprehensive understanding of NaCl:Cu’s behavior, a detailed analysis, modifying the energy level parameters of the kinetic model based on existing literature data, was undertaken. Charge transfer rate differential equations and harnessed Rlanguage numerical algorithms were utilized to simulate the OSL properties of NaCl:Cu. This involved calculation of the changes in electron and hole center concentrations after each event. The results of the simulations revealed a robust correlation between the OSL sensitivity of NaCl:Cu crystals and the measurement temperature. This finding underscores the critical influence of temperature on the performance of NaCl:Cu in OSL applications, highlighting the need for a thorough exploration of these temperature-dependent effects. The study conducted a quantitative comparison between the simulated results of the OSL signal attenuation in NaCl:Cu crystals and experimental data on thermoluminescence (TL) signal attenuation available in the literature. Notably, the OSL signal demonstrated both attenuation and reverse attenuation phenomena. However, it was emphasized that the range of variation in the OSL signal remained within a relatively small range, contrasting sharply with the more pronounced degree of TL signal attenuation. This observation suggests that NaCl:Cu may exhibit unique characteristics in terms of signal behavior under certain conditions, and understanding these phenomena is crucial for its successful application in dosimetry. The research extends its focus to the dose response of NaCl:Cu crystals, revealing intriguing findings. Within the 0-200 Gy range, the dose response is linear, indicating a proportional relationship between the applied dose and the OSL signal. Moreover, a saturation trend is observed at 200 Gy, suggesting that beyond this point, the crystal’s response may reach a plateau, with further increases in dose having diminishing effects on the OSL signal. The methodology employed in this study, combining charge transfer rate differential equations with R language numerical algorithms, proved to be effective in accurately predicting the OSL signal of NaCl:Cu crystals. The robustness of this approach further underscores the potential of NaCl:Cu crystals as an excellent dose component. However, it’s important to note that while the study provides valuable insights, there are inherent limitations. Future research should address these limitations, especially in the context of high doses, prolonged exposures, and more detailed observations, to further validate and refine the findings. In conclusion, the study marks a significant step forward in understanding the intricate properties of NaCl:Cu and opens avenues for its continued exploration and application in the field of dosimetry.

     

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