thermoluminescence

热释光
  • 文章类型: Journal Article
    在这项研究中,Ce3+掺杂Lu3Al5O12石榴石(LuAG)晶体探测器,密度为ρ=6g/cm3,有效原子序数Zeff=62,被建议作为有前途的放射治疗材料。这种类型的检测器具有出色的结构和光学特性均匀性,高热释光(TL)光产额,在245-295°C左右的温度下,主要TL辉光峰的最佳位置,和高辐射稳定性。由LuAG:Ce单晶制成的TL探测器组用于评估来自医学物理系6MV和15MV束的临床加速器的X射线辐射的剂量和能谱的均匀性,比得哥什肿瘤中心,波兰,和来自华沙国立肿瘤研究所60Co源的γ射线。LuAG:Ce晶体探测器在记录来自加速器的6MV和15MV电子束的X射线辐射方面表现出非常有希望的结果,以及来自能量为1.17和1.33MeV的60Co源的γ射线。
    In this study, Ce3+-doped Lu3Al5O12 garnet (LuAG) crystal detectors, with a density of ρ = 6 g/cm3 and an effective atomic number Zeff = 62, are proposed as promising materials for radiotherapy applications. This type of detector demonstrates excellent uniformity of structural and optical properties, high thermoluminescence (TL) light yield, optimal position of main TL glow peaks at temperatures around 245-295 °C, and high radiation stability. The set of TL detectors made from LuAG:Ce single crystal was used to evaluate the uniformity of dose and energy spectra of X-ray radiation from a clinical accelerator with 6 MV and 15 MV beams at the Department of Medical Physics, Oncology Center in Bydgoszcz, Poland, and γ-rays from a 60Co source at the National Institute of Oncology in Warsaw. The LuAG:Ce crystal detectors demonstrated highly promising results for registering X-ray radiation from accelerators with both 6 MV and 15 MV electron beams, as well as γ-rays from a 60Co source with energies of 1.17 and 1.33 MeV.
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  • 文章类型: Journal Article
    采用共沉淀法制备了不同浓度Cu掺杂的CaB2O4纳米棒。记录的CaB2O4:Cu样品在不同浓度的Cu下用6Gy的X射线辐照下的热释光(TL)和光激发发光(OSL)显示0.05at。wt%的Cu浓度具有更高的灵敏度。使用“tgcd”和常规拟合方法评估了辉光曲线的TL和OSL动力学参数。CaB2O4:Cu的TL辉光曲线具有三个单独的辉光峰,最大峰温度分别在404.50、453.04和484.02K。CaB2O4:Cu纳米颗粒的OSL辉光曲线遵循非一级动力学,可以用两个一级衰减曲线的总和拟合。
    CaB2O4 nanorods doped with different concentrations of Cu were prepared by using co-precipitation method. The recorded Thermoluminescence (TL) and Optically stimulated luminescence (OSL) of CaB2O4:Cu samples for different concentrations of Cu irradiated with 6 Gy of X-Ray shows that 0.05 at.wt% of Cu concentrations have higher sensitivity. The TL and OSL kinetic parameters of glow curves were evaluated using \"tgcd\" and conventional fitting methods. The TL glow curve of the CaB2O4:Cu have three individual glow peaks with maximum peak temperatures at 404.50, 453.04 and 484.02 K respectively. The OSL glow curves of the CaB2O4:Cu nanoparticles follow non-first order kinetics which can be fitted with the sum of two first order decay curves.
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  • 文章类型: Journal Article
    任何实验性的热释光(TL)辉光峰都包含绝缘材料带隙内其相应能级的活化能信息。峰形方法理论(PSM)通过假设TL峰下的面积可以近似为三角形的面积,将单个TL峰的宏观几何特征与负责TL峰的水平的活化能相关联。这样,几何特性成为活化能的量度。在目前的工作中,推导了新的PSM表达式,这不是现有的经验,而是基于一个陷阱一个重组(OTOR)中心的物理模型。考虑了三种情况。(I)用于重捕获概率小于重组概率的离域OTOR。(II)用于重捕获概率大于重组概率的离域OTOR。(三)局部转换OTOR模型。使用LambertW函数(或等效的Wrightω函数)对每种情况模型的微分方程系统进行了解析求解。然后,将所得的TL强度随温度变化的解析表达式用于推导新的PSM。所有案例中的新PSM在形式上完全相同,having,然而,它们的系数有很强的差异。测试新表达式的功能,并将其与现有PSM进行比较。
    Any experimental Thermoluminescent (TL) glow-peak contains the activation energy information of its corresponding energy level within the band gap in insulating materials. The theory of peak shape methods (PSM) correlates the macroscopic geometrical characteristics of a single TL peak with activation energy of the level responsible for the TL peak by assuming that the area under a TL peak can be approximated by the area of a triangle. In this way the geometrical characteristics becomes the measure of the activation energy. In the present work new PSM expressions are derived, which are not empirical as the existing ones but are based of the physical model of one trap one recombination (OTOR) center. Three cases are considered. (I) Delocalized OTOR for re-trapping probability smaller than the recombination probability. (II) Delocalized OTOR for re-trapping probability greater than recombination probability. (III) Localized transitions OTOR model. The system of differential equations of each case model were solved analytically using the Lambert W function (or equivalently the Wright ω function). Then the resulted analytical expressions of TL intensity as a function of temperature were used to derive new PSM. The new PSM from all cases are formally exactly the same, having, however, strong differentiation in their coefficients. The functionality of the new expressions is tested and its comparison with pre-existing PSM is performed.
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  • 文章类型: Journal Article
    本研究旨在研究紫外线C(UVC)辐射对低密度聚乙烯(LDPE)食品包装的影响。主要目标包括评估LDPE降解和使用放置在LDPE样品下的热释光剂量计(TLD)检测UVC辐射。暴露一小时后,结果确认准确的UVC检测,为优化食品处理程序提供了一个有用的工具。ATR-FTIR光谱分析显示UVC辐照的LDPE样品有细微的变化(透射率<8%),包括可能的CH断裂(2910和2848cm-1)和潜在的CC键振动(1470cm-1),在其他人中。然而,观察到的变化可能源于LDPE性能,而不是完全来自UVC辐射。对UVC诱导的热释光(TL)发射的比较研究提供了对各种TLD材料的见解。TL动力学分析,使用计算机辉光曲线去卷积(CGCD)方法,由于UVC暴露而公布的陷阱电荷激活,包括部分电离,漂白效应和光转移(PTTL)过程。LDPE样品放大了UVC-TL反应,揭示归因于PTTL过程的TLD之间的强度差异,由于缺乏退火处理而加剧。此外,TL探测器的化学成分,例如,type,浓度,number,其掺杂剂的氧化态和离子半径可能会影响UVC-TL响应。因此,TL强度比如下:GR-200(LiF:Mg,Cu,P)>TLD-100(LiF:Ti,Mg)>TLD-400(CaF2:Mn)>TLD-200(CaF2:Dy)。因此,GR-200检测电离辐射,但不能区分电离和非电离UVC辐射,而TLD-100作为UVC辐射探测器的有效性有限。相比之下,TLD-400适用于检测UVC辐射,TLD-200成为最有利的UVC检测器,显示一致的响应水平和最小的PTTL效应放置在LDPE样品下,而不需要热退火处理,使TLD-200在低成本测量方案中可重复使用。
    This research aims to study the effects of ultraviolet C (UVC) radiation on low-density polyethylene (LDPE) food packaging. Main objectives include evaluating LDPE degradation and detecting UVC radiation using thermoluminescent dosimeters (TLDs) placed under LDPE samples. Results confirm accurate UVC detection after one hour of exposure, providing a useful tool for optimize food treatment procedures. ATR-FTIR spectroscopy analysis revealed subtle alterations (<8 % transmittance relative) in UVC-irradiated LDPE samples, including possible CH breakage (2910 and 2848 cm-1) and potential CC bond vibrations (1470 cm-1), among others. However, observed variations may stem from LDPE properties rather than entirely from UVC radiation. A comparative study of UVC-induced thermoluminescence (TL) emissions provided insights into various TLDs materials. TL kinetic analysis, using computerised glow curve deconvolution (CGCD) method, unveiled trap charge activation due to UVC exposure, including partial ionization, bleaching effect and photo-transfer (PTTL) processes. LDPE samples amplified UVC-TL responses, revealing intensity differences between the TLDs attributed to the PTTL process, accentuated by the lack of an annealing treatment. Additionally, chemical composition of the TL detectors such as, type, concentration, number, oxidation states and ionic radii of their dopants may influence UVC-TL response. Consequently, TL intensity ratios follow as: GR-200 (LiF: Mg, Cu, P) > TLD-100 (LiF: Ti, Mg) > TLD-400 (CaF2: Mn) > TLD-200 (CaF2: Dy). Thus, GR-200 detects ionizing radiation but cannot distinguish between ionizing and non-ionizing UVC radiation, while TLD-100 has limited effectiveness as a UVC radiation detector. In contrast, TLD-400 is suitable for detecting UVC radiation and TLD-200 emerges as the most favorable UVC detector, showing consistent response levels and minimal PTTL effect placed under the LDPE samples without the need of a thermal annealing treatment that makes the TLD-200 to be reusable in a low-cost measurement protocol.
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  • 文章类型: Journal Article
    考虑到肿瘤治疗中中子和γ射线的低剂量检测要求,已经对新开发的磷光体LiAlO2:Gd进行了合成和探索性研究。我们的结果表明,Li和Gd的存在使其对伽马和热中子都敏感。LiAlO2:Gd对β的适用性,gamma,热刺激和光学刺激模式下的中子已经通过广泛的实验得到了验证,然后通过理论计算进行了动力学参数评估。目前的工作证实,LiAlO2:Gd是一种高度敏感的磷光体,γ的最小可检测剂量为5.7μSv,中子的最小可检测剂量为92μSv。发现磷光体在低能量和低剂量下显示非常高的灵敏度。其检测和辨别伽马和热中子的能力使其成为用于医学剂量测定的潜在材料。
    Considering the low-level dose detection requirement for neutron and γ radiation in cancer therapy, synthesis and exploratory studies have been performed on a newly developed phosphor LiAlO2:Gd. Our results reveal that the presence of both Li and Gd makes it sensitive to both gamma and thermal neutrons. The applicability of LiAlO2:Gd for beta, gamma, and neutrons in both thermally stimulated and optically stimulated modes has been verified by extensive experiments followed by kinetic parametric evaluation with theoretical calculations. The current work confirms that LiAlO2:Gd is a highly sensitive phosphor with a minimum detectable dose of 5.7 μSv for gamma and 92 μSv for themral neutrons. The phosphor is found to show very high sensitivity at low energy and dose. Its ability for detection and discrimination of both gamma and thermal neutrons makes it a potential material to be used in medical dosimetry.
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  • 文章类型: Journal Article
    在本研究中,通过常规溶胶-凝胶法成功合成了BaSrSiO4共掺杂的Yb3+和Nd3+纳米荧光粉(NPs),X射线衍射和扫描电镜分析证实,验证纯NP的形成。FTIR和拉曼光谱分析证实了硅酸盐的形成,在800-1000cm-1处看到Si-O和Si-O-Si的不同模式和振动。可见Nd3和Yb3离子之间的能量转移(ET)机制,因为发射光谱显示出一个比另一个的强度上升。当在785nm激发时,PLE发射光谱显示Yb3的2F7/2-2F5/2跃迁,Nd3的4F3/2跃迁至(4I9/2,4I11/2和4I13/2)。所有样品的活化能都很低,这表明所有样品的反应速率都会更高,1摩尔%Nd3+和1摩尔%Yb3+最高。τ的值随着Yb3+浓度的增加而增加,这证实了陷阱中心人口的增加。正电子an灭寿命(PAL)曲线表明,1mol%Yb3和2molNd3具有单个空位或较浅的正电子陷阱,而3摩尔%Yb3+和2摩尔%Nd3+具有较大的缺陷,如表面氧空位簇。另外两个样本有余额空缺,这使得它们最适合测温应用。计算荧光强度比(FIR)以获得测温应用的灵敏度。在303-333K温度下达到2.13%K-1灵敏度。
    In the present study, the synthesis of BaSrSiO4 co-doped Yb3+ and Nd3+ nanophosphors (NPs) was successfully achieved through the conventional sol-gel method, as confirmed by X-ray diffraction and SEM analysis, verifying the formation of pure NPs. The FTIR and Raman spectra analysis confirm the formation of silicates, as different modes and vibrations of Si-O and Si-O-Si were seen at 800-1000 cm-1. The energy transfer (ET) mechanism between Nd3+ and Yb3+ ions was seen as the emission spectra showed a rise in intensity of one over another. PLE emission spectra showed transitions at 2F7/2-2F5/2 for Yb3+ and from 4F3/2 to (4I9/2, 4I11/2, and 4I13/2) for Nd3+ when excited at 785 nm. All the samples record low activation energy, which shows that the rate of reaction will be higher in all the samples, and it will be highest for 1 mol% Nd3+ and 1 mol% Yb3+. An increasing value of τ was seen with increasing Yb3+ concentration, which confirms the increase in the population of trap centers. The positron annihilation lifetime (PAL) curve showed that 1 mol% Yb3+ and 2 mol Nd3+ have single vacancies or shallower positron traps, whereas 3 mol% Yb3+ and 2 mol% Nd3+ have larger defects like surface oxygen vacancy clusters. The other two samples have balance vacancies, which makes them best for thermometry applications. The fluorescence intensity ratio (FIR) was calculated to get sensitivity for thermometry application. 2.13% K-1 sensitivity achieved at 303-333 K temperature.
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  • 文章类型: Journal Article
    铝石榴石在掺入不匹配元素方面表现出卓越的适应性,从而促进具有定制性能的新型材料的合成。这项研究探索了Ce3掺杂的Tb3Al5-xScxO12晶体(其中x范围从0.5到3.0),揭示了一种通过原子尺寸失配工程控制发光和光转换的新方法。拉曼光谱证实了石榴石和钙钛矿相的共存,Sc取代显着影响石榴石晶格,并诱导A1g模式软化至Sc浓度x=2.0。Sc原子控制亚共晶夹杂物的形成,创建有效的光散射中心,并揭示八面体位置饱和的成分阈值。这种调制能够控制Ce3+和Tb3+离子之间的能量转移动力学,增强发光和减轻猝灭。Sc混合过程调节发光效率(LE),显色指数(CRI),和相关色温(CCT),CRI从68调整到84,CCT从3545K调整到12,958K。掺杂Ce3+的Tb3Al5-xScxO12晶体(其中x=2.0)达到了114.6lm/W的最高LE,并以4942K的CCT发射光,类似于白日。这种方法可以设计和开发具有适用于照明技术的定制光学特性的功能材料,持久性磷光体,闪烁体,和储存磷光体。
    Aluminum garnets display exceptional adaptability in incorporating mismatching elements, thereby facilitating the synthesis of novel materials with tailored properties. This study explored Ce3+-doped Tb3Al5-xScxO12 crystals (where x ranges from 0.5 to 3.0), revealing a novel approach to control luminescence and photoconversion through atomic size mismatch engineering. Raman spectroscopy confirmed the coexistence of garnet and perovskite phases, with Sc substitution significantly influencing the garnet lattice and induced A1g mode softening up to Sc concentration x = 2.0. The Sc atoms controlled sub-eutectic inclusion formation, creating efficient light scattering centers and unveiling a compositional threshold for octahedral site saturation. This modulation enabled the control of energy transfer dynamics between Ce3+ and Tb3+ ions, enhancing luminescence and mitigating quenching. The Sc admixing process regulated luminous efficacy (LE), color rendering index (CRI), and correlated color temperature (CCT), with adjustments in CRI from 68 to 84 and CCT from 3545 K to 12,958 K. The Ce3+-doped Tb3Al5-xScxO12 crystal (where x = 2.0) achieved the highest LE of 114.6 lm/W and emitted light at a CCT of 4942 K, similar to daylight white. This approach enables the design and development of functional materials with tailored optical properties applicable to lighting technology, persistent phosphors, scintillators, and storage phosphors.
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  • 文章类型: Journal Article
    聚羧酸锌粘固剂是少数显示与牙齿结构真正粘附的牙科材料之一。它适用于生物体而不会造成伤害。其对牙齿的强粘附性和低水平的刺激性是牙科应用的两个重要参数。在这项研究中,研究了使用热释光(TL)方法的聚羧酸锌水泥的剂量学性能,并确定了其用作良好剂量计的有效性。根据这项研究的结果,样品显示出良好的TL特性,在140°C左右发现三个主峰,220°C和330°C它具有72Gy至2.3kGy之间的宽线性剂量响应,并且在330°C时发现的TL峰具有良好的可重用性。不幸的是,TL峰强度值在短的等待时间间隔内迅速衰减。聚羧酸锌水泥,常用于牙冠,由于其在高剂量区域的宽线性剂量反应曲线,因此可用作回顾性剂量计,用于测量太空研究和核事故中的辐射量。
    Zinc polycarboxylate cement is one of the few dental materials that demonstrate true adhesion to tooth structure. It is suitable for use in living organisms without causing harm. Its strong adhesion to teeth and low level of irritancy are two important parameters for the dental applications. In this study, the dosimetry properties of zinc polycarboxylate cement using thermoluminescence (TL) method were investigated and determined the effectiveness of its use as a good dosimeter. According to the results of this study, the sample shows a good TL properties with three main peaks found around 140°C, 220°C and 330°C. It has a wide linear dose response between 72 Gy and 2.3 kGy and good reusability of the TL peak found at 330°C. Unfortunately, the TL peak intensity values are rapidly faded within a short waiting time interval. Zinc polycarboxylate cement, which is frequently used in dental crowns, can be used as a retrospective dosimeter for measuring the amount of radiation in space studies and nuclear accidents due to its wide linear dose-response curve in the high dose region.
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  • 文章类型: Journal Article
    在目前的工作中,(100-x)B2O3-xLi2O二元体系中的玻璃样品,x在30到50摩尔%之间变化,使用常规的熔融和模塑方法制备,主要目的是评估将这些材料暴露于紫外线(UV)辐射时的热释光响应。基于密度的互补分析,紫外可见区的光吸收(紫外可见吸收),傅里叶变换红外光谱在介质区域,X射线衍射,并进行了差热分析测量。玻璃样品的热释光测量显示,在50-250°C的温度范围内暴露于UV辐射后,辉光曲线具有至少一个最高温度为〜170°C的峰。样品还在25-275°C的温度范围内暴露于β辐射,还显示单峰,最高温度为~150℃。
    In the present work, glass samples in the (100 - x)B2O3-xLi2O binary system, with x varying from 30 to 50 mol%, were prepared using the conventional melting and moulding method, with the main objective of evaluating the thermoluminescence response when exposing these materials to ultraviolet (UV) radiation. Complementary analysis based on density, optical absorption on the UV-visible region (UV-vis absorbance), Fourier transform infrared spectroscopy on the medium region, X-ray diffraction, and differential thermal analysis measurements were performed. Thermoluminescence measurements of vitreous samples showed glow curves with at least one peak with a maximum temperature of ~170°C after exposure to UV radiation in the temperature range 50-250°C. Samples were also exposed to beta radiation in the temperature range 25-275°C, also showing single peaks with a maximum temperature of ~150°C.
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  • 文章类型: Journal Article
    通过将不同质量比的锆和氧化钛粉末混合,合成了具有不同杂质钛离子浓度的ZrO2陶瓷样品。X射线衍射分析用于确定相组成,晶格参数,以及掺杂浓度变化的陶瓷的微晶尺寸。用220MeVXe离子辐照样品至1010离子/cm2的通量后,观察到2.5eV的脉冲阴极发光带的强度降低。此外,离子辐照导致在450-650K处出现新的热释光峰,这归因于辐射诱导的电荷载流子陷阱。进一步的分析表明,用电子和离子辐照的样品的热释光曲线包含几个基本峰的叠加。值得注意的是,观察到阴极和热释光强度对钛浓度的复杂非单调依赖性,表明浓度猝灭的影响和隧穿跃迁的存在。
    Samples of ZrO2 ceramics with different concentrations of impurity titanium ions were synthesized by mixing zirconium and titanium oxide powders in different mass ratios. The X-ray diffraction analysis was used to determine the phase composition, lattice parameters, and crystallite size of the ceramics with varying dopant concentrations. Upon irradiation of the samples with 220 MeV Xe ions to a fluence of 1010 ions/cm2, a decrease in the intensity of the pulsed cathodoluminescence band at 2.5 eV was observed. Additionally, ion irradiation resulted in the emergence of a new thermoluminescence peak at 450-650 K attributed to radiation-induced traps of charge carriers. Further analysis revealed that the thermoluminescence curves of samples irradiated with electrons and ions comprise a superposition of several elementary peaks. Notably, a complex non-monotonic dependence of cathodo- and thermoluminescence intensity on titanium concentration was observed, suggesting the influence of concentration quenching and the presence of tunneling transitions.
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