Dosimetric, luminescence and scintillation properties of Ce-doped CaF2-Al2O3-B2O3 glasses
Dosimetric, luminescence and scintillation properties of Ce-doped CaF2-Al2O3-B2O3 glasses
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DOI：
10.1016/j.jnoncrysol.2018.12.025
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发表时间：
2019-04-01
影响因子：
3.5
通讯作者：
Yanagida, Takayuki
中科院分区：
文献类型：
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作者：
Kato, Takumi;Hirano, Shotaro;Yanagida, Takayuki
在电离辐射探测器中，发光材料已经被用于通过可见光子使辐射可视化。在这些发光材料中，将单个高能电离辐射立即转换为数千个紫外-可见光子的闪烁体是固态辐射探测器中最著名的类型，并且具有广泛的应用，例如医疗和安全[1-4]。另一方面，另一种发光型检测器，剂量计将吸收的能量储存数周，并通过热（热激发光，TSL）或光（光激发光，OSL）刺激释放。剂量计材料通常用作辐射环境中工作人员的定期辐射监测器，以监测累积剂量[5，6]。所需的剂量测定特性取决于应用，但通常考虑合适的灵敏度、剂量线性、能量响应和低衰减。此外，从生物等效性的角度来看，希望剂量计材料的有效原子序数（Zeff）接近人体软组织的有效原子序数（Zeff= 7.13）。利用这样的组织等效检测器，理想地不需要能量依赖性的数学校准。因此，对于这种剂量计应用，特别是在人体辐射监测器中，优选具有轻元件的检测器材料。发光剂量计的形式主要有块状单晶、陶瓷和玻璃[7-9]。在这些材料中，玻璃具有优选的性质，例如大规模的廉价生产率和灵活的化学组成和设计。然而，很少有研究试图将玻璃应用于剂量计材料。今天，在个人剂量监测应用中，大多数研究涉及单晶和陶瓷。因此，近年来，我们的研究小组开始研究具有各种化学成分的玻璃材料的剂量学特性[10-19]。例如，我们报道了Ce掺杂的CaO-Al 2 O3-B2 O3玻璃在辐射照射后通过热或光刺激由于Ce 3+离子的5d-4f跃迁而显示出发射，并且作为TSL剂量计具有1 mGy的灵敏度[20]。已知氟化物玻璃由于其低声子能量而在稀土离子掺杂下显示出优异的光致发光（PL）性质。由于氟化物玻璃的热稳定性和耐水性较差，氟氧化物玻璃和微晶玻璃受到人们的广泛关注。最近，Shinozaki等人报道，通过近紫外激发，Eu掺杂的50 BaF 2 - 25 Al 2 O3 - 25 B2 O3玻璃的高光致发光（PL）量子产率（QY）为97%[21]。优异的PL特性将对玻璃的剂量测定特性产生积极影响。在这项研究中，我们试图制造新的氟氧化物玻璃的剂量学性能。制备了xCeF_3-（30-x）CaF_2 - 20 Al_2 O_3 - 50 B_2 O_3（x= 0，0.75和2.0）玻璃，研究了其光学、闪烁和剂量学性质。
In ionizing radiation detectors, luminescence materials have been utilized to visualize radiations by visible photons. Among such luminescence materials, scintillators which convert a single high energy ionizing radiation to thousands of ultraviolet-visible photons immediately are the most famous type of the solid state radiation detector and have a wide range of applications such as medical and security [1–4]. On the other hand, another luminescence type detector, dosimeter storages the absorbed energy for several weeks and release by thermal (thermally-stimulated luminescence, TSL) or optical (optically-stimulated luminescence, OSL) stimulation. Dosimeter materials are often used as periodic radiation monitors for people working in the radiation environment to monitor the cumulated dose [5, 6]. Required dosimetric properties depend on applications, but typically suitable sensitivity, dose linearity, energy response and low fading are considered. In addition, it is desirable that the effective atomic number (Zeff) of the dosimeter material, in the view point of bioequivalence, is close to that of the human soft tissue (Zeff= 7.13). With such a tissue equivalent detector, no mathematical calibration for energy dependence is required ideally. Therefore, for such dosimeter applications especially in the human radiation monitor, it is preferred for the detector materials with light elements. The forms of dosimeter with luminescent are mainly bulk single crystals, ceramics and glasses [7–9]. Among these materials, glasses have preferable properties such as inexpensive productivity on a large scale and flexible chemical composition and design. However, few studies have attempted to apply glasses to dosimeter materials. Today, in personal dose monitoring applications, most researches deal with single crystals and ceramics. Hence, in recent years, our research group has started to investigate dosimetric properties of glass materials with various chemical compositions [10–19]. For instance, we reported that the Ce-doped CaO-Al2O3-B2O3 glass shows an emission due to 5d-4f transition of Ce3+ ions by heat or light stimulation after radiation irradiation and has 1 mGy of the sensitivity as TSL dosimeter [20].Fluoride glasses are known to show excellent photoluminescence (PL) properties with rare earth ion doping because of their low phonon energy. As fluoride glasses have poor thermal stability and water resistance, oxyfluoride glasses and glass-ceramics have been received much attention. Recently, Shinozaki et al. reported that the highly photoluminescence (PL) quantum yield (QY) of 97% in Eudoped 50BaF2-25Al2O3-25B2O3 glass by near-UV excitation [21]. Excellent PL characteristics would have a positive impact on the dosimetric properties of glasses. In this study, we attempted to fabricate new oxyfluoride glasses with dosimetric properties. We prepared xCeF3-(30-x) CaF2-20Al2O3-50B2O3 (x= 0, 0.75 and 2.0) glasses, and investigated the optical, scintillation and dosimetric properties.