Thermoluminescence Techniques Research Articles

Usability of sand samples in TL Radiation Dosimetry.

This study investigated natural sand thermoluminescence (TL) response as a possible option for retrospective high-dose gamma dosimetry. The natural sand under investigation was collected from six locations with selection criteria for sampling sites covering the highest probability of exposure to unexpected radiation on the Egyptian coast. Dose-response, glow curve, chemical composition, linearity, and fading rate for different sand samples were studied. Energy Dispersive X-ray Spectroscopy (EDX) analysis revealed differences in chemical composition among the various geological sites, leading to variations in TL glow curve intensity. Sand samples collected from Ras Sedr, Taba, Suez, and Enshas showed similar TL patterns, although with different TL intensities. Beach sands of Matrouh and North Coastal with a high calcite content did not show a clear linear response to the TL technique, in the dose range of 10Gy up to 30kGy. The results show that most sand samples are suitable as a radiation dosimeter at accidental levels of exposure. It is proposed here that for high-dose gamma dosimetry with doses ranging from 3 to 10kGy, a single calibration factor might be enough for TL measurements using sand samples. However, proper calibration might allow dose assessment for doses even up to 30kGy. Most of the investigated sand samples had nearly stable fading rates after seven days of storage. The Ras Sedr sands sample was the most reliable for retrospective dose reconstruction.

Investigation of structural, photo and thermoluminescence properties of YAGG:Ce nanogarnet for medical dosimetry application

Cerium-doped yttrium aluminum gallium garnet (YAGG:Ce3+) nanophosphors were synthesized using the sol-gel method. Mixed garnet of Y2.97Al5-xGaxO12:Ce0.03 was prepared with varying gallium content: x = 0, 1, 2 and 3 Ga. The effect of gallium substitutions on the structural, photo and thermoluminescence properties of the prepared nanophosphors were studied by X-ray diffraction (XRD), photoluminescence (PL) and thermoluminescence (TL) techniques. XRD results indicated that the single and pure cubic crystal phase was formed for all nanophosphor samples regardless of the Ga content. The PL spectra of all the samples exhibited a green-yellow emission band centered at 522 nm attributed to the 5d → 4f transitions of Ce3+ ions. The TL glow curve spectra recorded after β-particle irradiation showed a strong dependence in terms of position, shape and intensity, of all temperature peaks with the Ga content. The highest TL sensitivity was observed for the sample prepared with x = 2 Ga, with main peak arising at low temperature (85 °C). The sample prepared at x = 1 Ga exhibited also high TL sensitivity with a simple glow curve spectrum showing a main peak at high temperature (∼158 °C). Thus, the linear dose response of this sample has been investigated in the wide dose range from 0.125 to 100 Gy in order to evaluate the potentiality of this material for radiation dosimetry applications.

Thermoluminescence Characteristics of Copper and Terbium Co-Doped Lithium Tetraborate Glass

In this study, the preparation and characterization of copper (Cu) and terbium (Tb) co-doped lithium borate glass using spectroscopic and thermoluminescence techniques are reported. A thermal treatment was introduced to increase the degree of crystallinity. The thermoluminescence glow curve signal of the samples displayed upon exposure to beta radiation was measured and analyzed. It was found that the samples doped with 0.1% of copper and co-doped with 0.3% terbium showed the highest thermoluminescent (TL) signal in response to the irradiated dose. The analyses revealed that the glow curves of the doped samples were composed of nine overlapping glow peaks with activation energies between 0.73 and 2.78 eV. As a whole area under the glow curve, the TL signals displayed a linear dose response in the range from 110 mGy to 55 Gy. The minimum detectible dose of the samples was found to be 10.39 µGy. It was found that peaks 1 and 2 disappear after one day of storage. The rest of the peaks (3–9) remain almost constant up to 74 days of storage.

Studying the kinetic parameters of BaTi5O11 by using the thermoluminescence technique

The present study discusses the thermoluminescence (TL) characteristics of monoclinic barium titanate (BaTi5O11) which is chemically prepared using the sol–gel technique. The crystallinity is confirmed by X-ray diffraction, and the oxidation state of each element, morphology, and particle size of the prepared powder are chemically probed by different spectroscopic tools including X-ray Photoelectron Spectroscopy and Energy dispersive X-Ray spectroscopy. The sample is irradiated by a beta (β)-source with different applied doses in the range of 1.1––385 Gy. The kinetic parameters which correspond to the charge carrier traps were determined. The analysis methods indicated that the TL glow curve of BaTi5O11 consists of 6 overlapped peaks corresponding to 6 electron traps. The values for the trap depth are found to be in the range 0.94–1.40 eV and the TL glow peaks are located between 380.4 and 560.5 K. The study confirms the potential of BaTi5O11 for β-dosimetry.

Luminescence investigation of CaY2 Al4 SiO12 :Dy3+ phosphor synthesized by sol-gel method.

Dy3+ -doped CaY2 Al4 SiO12 phosphors were prepared using the sol-gel method. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive spectroscopy analyses (EDS) were used to analyse the crystal structure, morphology, and elemental composition of the prepared samples. The luminescence behaviour of the sample was investigated using photoluminescence (PL) and thermoluminescence (TL) techniques. The prepared CaY2 Al4 SiO12 :xDy3+ phosphor showed a characteristic blue and yellow emission at ~480 and 583 nm, respectively, with an excitation wavelength of 350 nm. The most intense PL emission was found for a 4mol% doping concentration of Dy3+ ions. The CIE diagram of the phosphor showed bluish-white colour emission. For TL studies, the prepared phosphors were irradiated with a 60 Co γ (gamma) source and the TL glow curve of the CaY2 Al4 SiO12 :0.04Dy3+ phosphor showed three overlapped peaks. For the Gaussian peaks, Chen's peak shape method was applied to determine the kinetic parameters of the samples.

An overview study on the TL and OSL dosimetry patent processes over time

Since its discovery, ionizing radiation has been used in many different applications. Materials and methods have been developed to measure and quantify radiation doses. Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) are two techniques used for radiation dosimetry. Both TL and OSL are primarily applied in several areas, such as dating of ancient materials, equipment quality control and individual monitoring. One of the parameters to measure the knowledge and development of a technology is the number of patents related to the field. In this work, we established a methodology for patent search on the World Intellectual Property Organization (WIPO) database aiming to review the development of TL and OSL dosimetry over time. We concluded that along with the OSL technique development, the TL technique should continue to be explored in radiation dosimetry.

Green synthesis, structural and luminescent characterization of BaZrO3:Eu3+ nanoparticles

This paper presents experimental results of the structural, morphological, and luminescence characterization of Eu 3+ doped BaZrO 3 powders produced by the green synthesis method. The highly crystalized cubic structure perovskite powders of the formula BaZrO 3 were synthesized by the chemical hydrothermal method. The phase of the compound and the average particle size were determined using X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). Powder samples were characterized also by photoluminescence (PL) and thermoluminescence (TL) techniques. Results showed that BaZrO 3 crystallizes in its perovskite cubic phase, with a crystal size circa 40 nm. The presence of each element of the compound was confirmed by the energy disperse spectroscopy (EDS) technique. The PL emission spectra, at room temperature, were obtained using 395 nm as excitation wavelength. The spectra showed the characteristic emissions of Eu 3+ ion. The intensity of the PL emission spectra varies with the Eu 3+ concentration and shows a maximum luminescence efficiency when the synthesis of BaZrO 3 was performed using a content of 5 mol% Eu³⁺. The thermoluminescence data shows that at the heating rate of 10 °C/s, BaZrO 3 :Eu 3+ doped with 5% of dopant concentration exhibits two TL peaks: first of them rapidly decaying peaks at about 110 °C and a high sensitivity peak at 235 °C TL. The correlation between luminescence intensity and concentration quenching of the prepared phosphor was investigated. Present findings substantiate the ability of the BaZrO 3 nanopowder sample to be a promising candidate for luminescence applications.

Luminescence dating and firing temperature determination of ancient ceramics fragments from the Tunata-hill site in the Churajon archaeological complex in Arequipa, Peru

Ancient pottery fragments from the Tunata-hill site in Churajon archaeological complex, Arequipa, Peru, were dated by means of luminescence techniques such as thermoluminescence (TL) and optically stimulated luminescence (OSL) in order to provide absolute chronology. For TL, additive and regenerative methods were performed. For OSL a regenerative method was carried out for IRSL dating. A rigorous description of the study area and its context has been made. The ages of the samples were found to be between 0.50 ± 0.06 ky and 0.49 ± 0.03 ky for TL methods, and 0.49 ± 0.02 ky for OSL methods. On average, the estimated age by TL and OSL techniques is 490 ± 70 yr (1600 AD and 1460 AD). This means that Churajon ceramics under study would belong to the Late periods which corresponds to the Inca region, and the North sub-region of the Late Churajon phase, and the beginning of European colonization in Peru. X-ray fluorescence technique (XRF) analysis has shown the main presence of Fe (39.5%), Si (30.0%), and Al (10.4%) in fine pottery powder. Furthermore, the electron paramagnetic resonance (EPR) technique was used to study the firing temperature using the iron signal (Fe3+) as a firing temperature reference. The firing temperature of ceramics was found to be around 550 ± 50 °C.

Comparison of thermoluminescence characteristics of undoped and europium doped YAl3(BO3)4 phosphor synthesized by combustion method: Anomalous heating rate, dose response and kinetic analyses

In this study, undoped and YAl3(BO3)4 phosphors doped with Eu3+ at varying concentrations (x = 0.5 to 7 wt%) produced by a combustion process have been thoroughly examined by using the X-ray diffraction (XRD) and thermoluminescence (TL) techniques. The crystallized phosphors were confirmed by XRD analysis, and its crystal structure was examined. XRD analyses of the synthesized phosphor is in accordance with ICSD File No 96-152-6006. TL glow curve of undoped sample produced three glow peaks located at 80 °C, 240 °C, and 360 °C with a heating rate of 2°Cs−1 whilst Eu3+ doped one appears at 90 °C, 230 °C, and 390 °C. The undoped example complied with the theory as expected, namely, as the heating rate increased, the TL glow curve shifted towards lower temperatures and decreased in intensity. However, an anomalous change was observed in the sample with Eu3+ additive. The experimental findings from the dose-response of YAl3(BO3)4:0.5 wt%Eu3+ demonstrate that the intensity of TL provided by the total area under glow curves has an acceptable linearity (r2:0.999) up to 100 Gy. The intensity of each maximum on the TL glow curve augments proportionally as the heating rate is augmented. Possible reasons of this behaviour are discussed. Various heating rate (VHR) methods (such as Hoogenstraaten's and Booth-Bohun-Parfianovitch) have also been used to estimate kinetic parameters (e.g., energy and frequency factor), which seem to be in good agreement with each other.

Thermoluminescence characteristics and kinetic analyses of europium doped strontium gadolinium oxide phosphor

In this work, SrGd2O4 phosphors incorporated with Eu3+ at various dopant concentrations are synthesized via solid state reaction method. An X-ray diffraction (XRD) and thermoluminescence (TL) technique were used to examine the structural and thermoluminescent properties of as-prepared phosphors. Orthorhombic phase formation of Eu3+ doped samples was confirmed by XRD. The influence of impurity concentration and heating rates on the glow curves was also investigated. Anomalous heating rate pattern was observed in the sample with Eu3+ additive. A model of semi-localized transition was used to explain this behaviour. The TL glow curves of beta irradiated SrGd2O4:Eu3+ (0.25 mass %) reveal three well-resolved peaks at 105, 189, and 245 °C. Various heating rates, TM–Tstop, initial rise, and computerized glow curve deconvolution techniques were employed to detect the overlapping peak numbers and establish the kinetic parameters of SrGd2O4:Eu3+ (0.25 mass %). When the trap numbers and comparable energy values are considered, the findings of the approaches are very similar. For the dose ranges between 0.1 and 8 Gy, SrGd2O4:Eu3+ (0.25 mass %) samples exhibited linear behaviour, and high reproducibility, indicating their applicability for TL dosimetry applications.

Linear charging-discharging of an ultralong UVA persistent phosphor for advanced optical data storage and wide-wavelength-range detector

Ultraviolet persistent luminescence (UV PersL) phosphor is currently gaining considerable attention due to its promising potential for widespread advanced applications. However, the linear manipulation of electron charging-discharging and the prolongation of persistent time remains a huge challenge. Here, we report a novel Bi3+ doped Mg2GeO4 UVA PersL phosphor via a nonequivalent substitution strategy. The UVA PersL performance of Mg2GeO4:Bi3+ is significantly improved by introducing Li+ ions, yielding a superior UVA PersL property with afterglow lasting time beyond 100 h. The trap distribution management and the captured electron motion dynamics are revealed by the thermoluminescence technique under various external stimuli. Moreover, UVA PersL can be repeatedly rejuvenated by NIR and blue LED stimulation owing to the optically stimulated electrons from different depth traps to shallow traps. Due to the invisibility of UVA light, barcode information stored on the phosphor film can be read by NIR light and then erased by blue light, exhibiting the potential application in optical data storage with good concealment and security. Most remarkable is the electron charging-discharging linear functions of the irradiated power of UV, and blue and NIR light which was never reported, providing a feasible approach for optical power detection in a wide-wavelength-range. This work not only offers a guideline to develop novel high-performance UV PersL materials but also provides a route to effectively manipulate the electrons in the traps toward applications in advanced optical information storage and wide-wavelength-range light detection.

Low temperature luminescence and tunnelling effect in the Sr4Al14O25 co-doped with Eu2+and Dy3+ persistent luminescent phosphor

Thermoluminescence (TL) technique is very useful in the research of persistent Luminescence (PL) phosphors. It gives information about the existence of energy levels within the forbidden band and lifetime. The TL glow curve of Sr4Al14O25: Eu2+,Dy3+ persistent phosphor consists of two well-separated glow peaks at around 353 K and 438 K after both UV radiation and beta irradiation. To study the low temperature (≤ room temperature) glow peaks, low temperature TL (LTTL) measurements were performed with a homemade system after exposed to UV radiation. The sample was heated according to T(t)=T∞−(T∞−T0)e−αt equation starting from liquid nitrogen temperature, 77K. Besides the peaks at around 345 and 445 K according to LTTL results, Sr4Al14O25: Eu2+,Dy3+ has two more well-separated low temperature TL peaks at around 170 K and 295 K.The lifetime of the TL glow peaks (at 353 K and 438 K) was calculated according to s−1exp(EkT) and the results were checked with fading tests. Moreover, TL sensitivity tests were carried out both with and without preheating. Finally, tunnelling effect was evaluated by using the results of sensitivity tests and fading tests. Interesting results were observed at sensitivity tests performed with preheating. The results indicates that the behaviour of two glow peaks is very different from each other. The mechanism behind the peak around 438 K is localised transition involving a tunnelling effect.

TL and OSL characteristics of the fluoroperovskite KMgF3:Eu,Yb, Li for dosimetry applications

The purpose of this work was to investigate the dosimetric and luminescence properties of the novel KMgF3:Eu0.5%,Yb0.1%,Li15% fluoroperovskite synthesized using the sol-gel method. The luminescence signals were characterized using Optically Stimulated Luminescence (OSL) spectra, Linearly-Modulated OSL (LM-OSL), Continuous-Wave OSL (CW-OSL), and Thermoluminescence (TL) techniques. The blue light (470 nm) stimulated OSL associated with Eu2+, and Eu3+ emissions was correlated with the TL peaks up to 300 °C. The photoionization cross-section of each OSL component was evaluated using deconvolution analysis following two different optical stimulation modes, namely LM-OSL and CW-OSL. The activation energy values were evaluated using the Tm-Tstop and CGCD methods. OSL signal fading of 5% and 13% was observed at the end of 24 h and over the next three months, respectively. The results indicate that the OSL from KMgF3:Eu0.5%,Yb0.1%,Li15% fluoroperovskite has suitable properties for dosimetry, including high sensitivity to ionizing radiation and a wide linear dose range (0.1–500 Gy). These results enhance the understanding of the origin of the luminescence properties in this material and this work paves the way toward its utility for dosimetry purposes.

Effects of manganese and terbium on the dosimetric properties of CaSO4

In this study, a new CaSO4 crystal doped with manganese and terbium is described and its potential for dosimetric applications is evaluated. Crystals were synthesized using the slow evaporation route, and were prepared in pellet form with the addition of Teflon. CaSO4 was doped with manganese and terbium at a concentration of 0.1 mol% in each case. The crystalline structure and optical properties of the crystals were evaluated by X-ray diffraction, Fourier transform infrared spectroscopy and photoluminescence. The suitability of these crystals for thermoluminescent (TL) and optically stimulated luminescent (OSL) dosimetry was also investigated. The material showed adequate OSL and TL characteristics, such as a TL glow curve with two peaks at approximately 205 °C and 325 °C, an adequate OSL decay curve, good reproducibility, and linearity of the luminescent signals, when irradiated with doses of between 200 mGy and 150 Gy. Two trapping centers located at 0.77 and 1.02 eV were revealed. The heating rate dependence was also evaluated. The lowest detectable dose was investigated by the TL and OSL techniques, and the results were presented in mGy for both methods. It was also observed that co-doping with Mn and Tb contributed to a reduction in fading compared to CaSO4:Mn and CaSO4:Tb.

Studies of defect states and kinetic parameters of car windscreen for thermoluminescence retrospective dosimetry

In case of any natural disasters or technical failures of nuclear facilities, the surrounding media including human beings may receive unexpected radiation exposures. In such a situation, there is no viable way to know how much radiation dose is received by human beings. Realizing that motorized vehicles are parked at fixed but increasing distances within the nuclear installation and industrial environment, this study investigates the kinetic parameters of readily available car windscreens which form the basis to be employed in post-accident dose reconstruction or for retrospective dosimetry. To understand the luminescence features of this crystalline media, a convenient thermoluminescence (TL) technique has been employed. Several well-defined theoretical models and methods were employed to calculate the kinetic parameters including the order of kinetics (b), activation energy (E) or trap depth, frequency factor (s) or escape probability and trap lifetime (τ), by analyzing the glow curves of the irradiated samples. The analysed trapping parameters indicate that the Toyota (E = 0.75–1.31 eV, s = 3.0E+6 – 3.7E+9 (s−1), τ = 6.9E+5 – 1.3E+14 s) and Honda (E = 0.95–1.68 eV, s = 2.1E+10 – 4.1E+13 (s−1), τ = 2.2E+9 – 3.1E+20 s) windscreen offer promising features for conventional TL dosimetry applications, while the obtained longer lifetime (τ = 6.8E+10 – 8.6E+29 s) or higher activation energy (E = 1.23–2.15 eV) for Proton brand windscreen indicates better stability or slow fading of the material, thus suitable for retrospective TL dosimetry. In addition, by assessing the area of deconvoluted micro-Raman spectra of windshield glasses in high-frequency regions, it has been observed the phenomenon of dose-dependent structural alterations and internal annealing of defects. This pattern is also consistent with those cyclical pattern observed in the intensity ratio of defect and graphite modes in the studies of carbon-rich media. Such common phenomena indicate the possibility of using the Raman microspectroscopy as a probe of radiation damage in silica-based media.

Study of the dosimetric properties of CaSO4:Dy using OSL technique

Calcium sulfate doped with dysprosium (CaSO4:Dy) has been used for personal dosimetry using the thermoluminescence (TL) technique for decades and its TL properties are well-known. Considering the advantages of the OSL technique (relatively simple and faster readout and detector reusability) and the potential applicationof CaSO4:Dy as an OSL detector, this study aimed to investigate the dosimetric properties of CaSO4:Dy using the OSL technique. The present study was carried out using CaSO4:Dy pellets prepared at IPEN irradiated and read in a TL/OSL Risø reader with blue light stimulation and Hoya U-340 filter. OSL dosimetric properties essentially dose response, reproducibility, and fading characteristics were evaluated. Moreover, TL and OSL signals were compared to study the correlation between OSL signals and TL peaks. CaSO4:Dy OSL response is linear from 0.1 to 10 Gy and shows reproducibility better than 5%. The low-temperature TL peak is unstable; however, the OSL signal seems to be associated with higher-temperature peaks.

Exploring the application of blue and red thermoluminescence for dating volcanic glasses

Tephras are significant markers in the stratigraphic record and play a key role in establishing paleoenvironmental and paleoclimate histories worldwide. Despite burgeoning research focused on tephra characterization and correlation techniques, there are still few techniques that allow for the direct dating of tephra, particularly below the lower age limit of K/Ar and Ar/Ar dating methods. In this study, we test different thermoluminescence (TL) dating approaches on the 4–11 μm volcanic glass constituents of three different independently different tephras. By comparing against independent age control, we demonstrate the utility of both blue (320–450 nm) and red (587–651 nm) TL emissions for dating volcanic glasses using single aliquot regenerative (SAR) dose techniques. We find that both blue and red TL emissions from the volcanic glass shards are dim but reproducible and show no evidence for significant sensitivity changes occurring between the natural TL and the first test dose during the SAR protocol. Fading tests on the blue TL signal show that g-values range from 1.6 ± 1.0 to 2.9 ± 1.1%/decade and are statistically indistinguishable with zero at 2σ for the red TL. Bleaching experiments show that both blue and red TL signals are sensitive to light exposure, with sensitivity corrected signals declining by ∼40% over a 2-h period. For all three tephras, both the fading-corrected blue and red SAR-TL ages are consistent with age expectation. These successful results demonstrate the effectiveness of TL techniques for determining the eruption ages of tephra deposits in primary position between ∼1 and at least 30 ka.

Molecular mobility in bulk and in near-surface nano-layers of ultra-high-molecular-weight polyethylene

A comparative study of molecular dynamics in near-surface nanolayers and in a bulk of polyethylene is presented. Molecular mobility in near-surface nanolayers of polyethylene reactor powders and melt-crystallized films of various molecular weights prepared in different crystallization conditions were studied with the help of thermoluminescence technique using high frequency glow dicharge Ar plasma for surface activation. Molecular mobility in a bulk of the same samples was investigated by the method of radio thermoluminescence, in which a deeply penetrating γ-quanta from 60Co radiation was used for activation of the bulk. A marked difference in a temperature position of the peaks on the glow curves of plasma-induced thermoluminescence and those of radiothermoluminescence correspoding to γ- and ß-transitions was found to depend on crystallisation conditions and molecular weight. Quasi-independent segmental mobility (ß-relaxation) in the near-surface nano-layers of UHMWPE reactor powder particles synthesized at low temperatures appeared to be unexpectedly unfreezed at the temperature higher than that in the bulk. It was supposed that this happend because of crystallization under the confinement conditions during low-temperature polymerization leads to formation of a specific surface structure.

Gamma-ray induced thermoluminescence emission of green synthesized zinc oxide nanophosphors

The thermoluminescence (Thermally stimulated luminescence) technique has been applied in the field of radiation dosimetry and was found to be highly successful in dating ancient pottery samples. It is also used in the study of biological and biochemical systems. The present study reports the gamma-ray exposed thermoluminescence (TL) emission of ZnO nanophosphors. ZnO nanoparticles were prepared via phyto-mediated green routes according to our previous works. Different analytical techniques such as XRD, FESEM, HRTEM, XPS, EDS, FTIR, and UV-DRS were employed to characterize the samples. The ZnO nanoparticles possess hexagonal wurtzite crystal structure of with 29–71 ​nm particle dimension. TL emission of the samples was recorded with different gamma dosages10-50 Gy at a constant heating rate of 2oCs-1. A broad single glow curve above 300 ​°C was exhibited by the samples and good linearity was reserved in integrated TL profiles. The TL emission follows first-order kinetics and the activation energies of the traps located in the samples were determined.

Thermoluminescence Properties of Bioglass for Radiation Dosimetry

The thermoluminescence technique was employed to study bioglass matrix prepared using the traditional technique of glass making. The synthesized bioglass matrix were investigated using X-ray diffraction (XRD), and differential thermal analysis (DTA) has been studied. The highest thermoluminescent intensity was found for composition bioglass 26.91 % CaO, 45.68 % SiO2, 2.50 % P2O5, 25.094 %Na2O (mol%), with only one glow peak at 460 k. The TL response illustration is slightly sub-linear in the high gamma dose range from 25 to 1000 Gy. This new glass system might become useful in high-dose fields for dosimetry.