Rahat Md Raghib, Mimi Homaira Afia, Islam Shah Azharul, Kamruzzaman Md, Ferdous Jannatul, Begum Mahfuza, Hasnat Md Abul, Abdul-Rashid H A, Muslima Umme, Khandaker Mayeen Uddin, Bradley D A, Al-Mamun Md, Rahman A K M Mizanur
Department of Physics, Begum Rokeya University, Rangpur, Bangladesh.
Health Physics Division, Atomic Energy Centre Dhaka, Bangladesh Atomic Energy Commission, 4 Kazi Nazrul Islam Avenue, Shahbag, Dhaka, 1000, Bangladesh.
Appl Radiat Isot. 2023 Dec;202:111047. doi: 10.1016/j.apradiso.2023.111047. Epub 2023 Sep 27.
Many minerals and compounds show thermoluminescence (TL) properties but only a few of them can meet the requirements of an ideal dosimeter. Several phosphate materials have been studied for low-dose dosimetryin recent times. Among the various phosphates, ABPO-type material shows interesting TL properties. In this study, an ABPO-type (A = Lithium, B=Calcium) phosphor is synthesized using a modified solid-state diffusion method. Temperature is maintained below 800 °C in every step of phosphor preparation to obtain the pure phase of Lithium calcium phosphate (LiCaPO). The purpose of this work is to synthesize LiCaPO using a simple method, examine its structural and luminescence properties in order to gain a deeper understanding of its TL characteristics. The general TL properties, such as TL glow curve, dose linearity, sensitivity, and fading, are investigated. Additionally, this study aims to determine various kinetic parameters through Glow Curve Deconvolution (GCD) method using the Origin Lab software together with the Chen model. XRD analysis confirmed the phase purity of the phosphor with a rhombohedral structure. Lattice parameters, unit cell volume, grain size, dislocated density, and microstrain were also calculated from XRD data. Raman analysis and Fourier Transform Infrared analysis were used to collect information about molecular bonds, vibrations, identity, and structure of the phosphor. To investigate TL properties and associated kinetic parameters, the phosphor was irradiated with 6.0 MV (photon energy) and 6.0 MeV (electron energy) from a linear accelerator for doses ranging from 0.5 Gy to 6.0 Gy. For both photon and electron energy, TL glow curves have two identical peaks near 200 °C and 240 °C.The TL glow curves for 0.5 Gy-6 Gy are deconvoluted, then fitted with the appropriate model and then calculated the kinetic parameters. Kinetic parameters such as geometric factor (μ), order of kinetics, activation energy (E), and frequency factor (s) are obtained from Chen's peak shape method. The dose against the TL intensity curve shows that the response is almost linear in the investigated dose range. For photon and electron energy, the phosphor is found to be the most sensitive at 2.0 Gy and 4.0 Gy, respectively. The phosphor shows a low fading and after 28 days of exposure, it shows a signal loss of better than 3%. The studied TL properties suggest the suitability of LiCaPO in radiation dosimetry and associated fields.
许多矿物质和化合物都具有热释光（TL）特性，但其中只有少数能满足理想剂量计的要求。近年来，人们对几种磷酸盐材料进行了低剂量剂量测定的研究。在各种磷酸盐中，ABPO型材料表现出有趣的热释光特性。在本研究中，采用改进的固态扩散法合成了一种ABPO型（A = 锂，B = 钙）磷光体。在磷光体制备的每一步中，温度都保持在800°C以下，以获得磷酸锂钙（LiCaPO）的纯相。这项工作的目的是用一种简单的方法合成LiCaPO，研究其结构和发光特性，以便更深入地了解其热释光特性。研究了热释光发光曲线、剂量线性、灵敏度和衰退等一般热释光特性。此外，本研究旨在使用Origin Lab软件和Chen模型，通过发光曲线反卷积（GCD）方法确定各种动力学参数。XRD分析证实了具有菱面体结构的磷光体的相纯度。还从XRD数据计算了晶格参数、晶胞体积、晶粒尺寸、位错密度和微应变。拉曼分析和傅里叶变换红外分析用于收集有关磷光体的分子键、振动、特性和结构的信息。为了研究热释光特性和相关的动力学参数，用直线加速器的6.0 MV（光子能量）和6.0 MeV（电子能量）对磷光体进行0.5 Gy至6.0 Gy剂量范围的辐照。对于光子和电子能量，热释光发光曲线在200°C和240°C附近都有两个相同的峰。对0.5 Gy - 6 Gy的热释光发光曲线进行反卷积，然后用适当的模型拟合，再计算动力学参数。通过Chen峰形法获得几何因子（μ）、动力学级数、活化能（E）和频率因子（s）等动力学参数。剂量与热释光强度曲线表明，在所研究的剂量范围内响应几乎呈线性。对于光子和电子能量，发现磷光体分别在2.0 Gy和4.0 Gy时最敏感。该磷光体衰退率低，暴露28天后，信号损失优于3%。所研究的热释光特性表明LiCaPO适用于辐射剂量测定及相关领域。
