Thermoluminescence Glow Curves Research Articles

Luminescence of CsLa1-хCeхSiS4 thiosilicate solid solution: From STE to Ce3+ emission

A series of single crystals of CsLa1-хСехSiS4 monophasic solid solution (x = 0–1) has been obtained for the first time by high-temperature flux synthesis. Methods of XRD and chemical analysis, absorption and low-temperature (from T = 5 K) luminescent spectroscopy were used. The results of the band scheme calculating using density functional theory correlate with spectroscopy data. One non-elementary d → f emission band of Ce3+ ions is observed in the region of 520 nm in the luminescence spectra at room temperature at any value of the x parameter. The luminescence decay kinetics of Ce3+ ions upon excitation by a pulsed electron beam, X-ray synchrotron radiation or intracenter photoexcitation is characterized by a nanosecond component. As the parameter x increases, the decay time is reduced from 132 ns (x = 0.005) to 0.88 ns (x = 1). The luminescence decay kinetics upon photoexcitation at x = 0.005–0.12 is characterized by monoexponential decay with τ = 31.4 ± 0.2 ns. Concentration quenching of the Ce3+ ion photoluminescence is not observed up to the value of the parameter x = 0.12; it only appears at x = 1. The anomalously short decay time of the Ce3+ ions luminescence in CsCeSiS4 upon both X-ray excitation and photoexcitation is associated with concentration quenching.At temperature 5 K, new intense bands at 408 and 688 nm in addition to the Ce3+ emission band observed in the photoluminescence spectra of nominally pure CsLaSiS4 or at the lowest parameter value x = 0.005. These bands correspond to the luminescence of self-trapped excitons (STE) and defects. With increasing x parameter, the STE emission band is reabsorbed by the absorption of Ce3+ ions and is quenched due to the resonance energy transfer STE → Ce3+ center. Thermoluminescence glow curves of CsLa1-xCexSiS4 irradiated with X-ray at T = 90 K are characterized by several low temperature intense peaks, which indicates a high concentration of charge carrier traps.

Fading performance on optically stimulated luminescence of LiMgPO4:Tb,Sm,B

This study aimed to investigate the fading of the optically stimulated luminescence (OSL) of LiMgPO4:Tb,Sm,B. Thermoluminescence (TL) glow curves were recorded immediately and 24 h after irradiation, as well as after OSL. Peaks 2 and 3 did not contribute to the fading of the TL signal, while peak 1 was identified as the primary source of TL signal fading in LiMgPO4:Tb,Sm,B. The fading was calculated by considering the OSL signal measured immediately after irradiation as the first measurement point. About 70% of the OSL signal was measured 30 days after irradiation if the pre-heat procedure was not applied. The intensity of LiMgPO4:Tb,Sm,B remains stable at 93.1% with a preheating program of 160 °C for 30 s.

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.

Phosphorescence of beta irradiated Sr4Al14O25:Eu2+,Dy3+ ─ A persistent luminescence phosphor

Phosphorescence of beta irradiated Sr4Al14O25:Eu2+,Dy3+ has been analysed. The persistent luminescence that defines this phosphor is phosphorescence hence the justification for this study. A set of phosphorescence decay curves were measured at various temperatures Tph between 20 and 352 °C following irradiation to 2 Gy. The residual thermoluminescence (R-TL) was recorded at 1 °C/s after the phosphorescence decay. A conventional TL glow curve recorded at the same rate following irradiation to 2 Gy produces two composite glow peaks P1 and P2 at 63 and 252 °C respectively. The decay curves measured between Tph = 28–60 °C and 200–240 °C associated with peaks P1 and P2 respectively give the values of the activation energy of peaks P1 and P2 as 0.59 ± 0.01 and 0.80 ± 0.04 eV. The effective frequency factors associated with the traps are 6.2 × 109 and 6.4 × 105 s−1 respectively. Peaks P1 and P2 are affected by thermal quenching with activation energy W = 0.69 ± 0.06 eV and 0.66 ± 0.03 eV respectively. The R-TL glow curves show two maxima R1 and R2 at ∼72 and 260 °C respectively. Kinetic analysis of R-TL peak R2 shows a Gaussian distribution of trap energy whereas the same analysis on R-TL peak R1 shows a non-Gaussian distribution of trap energy. The mean values of activation energy corresponding to the respective electron traps of R1 and R2 are estimated to be 0.62 ± 0.07 and 1.04 ± 0.06 eV. For peak R2, the Gaussian distribution curve shows the maximum at ∼1.06 eV which indicates that most electron traps corresponding to peak R2 have this trap depth.

Elucidation of trap energies of Gamma-irradiated BaMgAl10O17: Ce3+ phosphors for dosimetry applications

AbstractThis paper presents a comprehensive examination of the thermoluminescence properties of BaMgAl10O17: Ce (BAM: Ce) phosphors, which were synthesized via the combustion method. The study employs five distinct approaches to determine the kinetic parameters for individual traps. To investigate the structural, morphological, and elemental composition of the samples, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were utilized. The photoluminescence spectra revealed a broad emission centered around 420 nm upon 330 nm excitation. By subjecting the phosphors to γ doses ranging from 5 to 5 kGy and conducting TL glow curve analysis, the kinetic characteristics of the BAM: Ce phosphors were determined. The linear dose–response was observed for 5–50 Gy, indicating a high sensitivity value. Additionally, there is a consistent estimation of trap energy across various methods. It is also worth noting that the phosphor exhibits a very low minimum detectable dose, estimated to be in the microgray range, making BAM: Ce a strong candidate for low gamma dosimetry applications.

Effect of IRSL-BLSL-TSL reading modes combination on thermoluminescence (TL) response of BeO dosimeter.

The ultimate goal of this work is the study of the effect of luminescence stimulations and signals reading modes combinations on the thermoluminescence intensity and glow curve behaviour for the same X-ray irradiation dose. Three interesting stimulating and reading modes are considered, namely, infrared stimulated luminescence (IRSL), blue light-emitting diode stimulated luminescence (BLSL) and thermally stimulated luminescence (TSL). The studied stimulation and reading modes combination protocols are (Protocol 1) IRSL-TSL, (Protocol 2) IRSL-BLSL-TSL and (Protocol 3) BLSL-IRSL-TSL. Experiments are performed on beryllium oxide (BeO) dosimeter. Results demonstrate well that the combination of reading modes have direct impact on the TL signal in terms of intensity and glow curve shape. It was also found that when reading modes are correctly combined, particularly when IRSL is applied first, then BLSL and TL, it is possible to collect two or more exploitable signals of different stimulation types for the same irradiation that can be used for different purposes and final applications.

Correlations between quartz OSL dose-response curve and TL glow curve characteristics, and their implications for equivalent dose estimation

Optically stimulated luminescence (OSL) dating of quartz using the single-aliquot regenerative-dose (SAR) procedure requires construction of dose-response curves (DRCs). The shapes of DRCs and their characteristic saturation doses (D0 values) are well-known to be highly variable between samples and among individual grains from the same sample, but the factors that control DRC characteristics are imperfectly understood. Here we report correlations between OSL DRC shapes and thermoluminescence (TL) glow curve characteristics for a sample of quartz from northern Australia. Individual grains were measured using the SAR procedure and one of two preheat temperatures (160 °C and 260 °C), and grouped according to similarities in their DRC shapes. Grains from each DRC group were then physically transferred onto a separate disc for TL measurement as a multi-grain aliquot. A strong correlation was observed between DRC group and laboratory-irradiated TL glow curve shapes, along with some differences between the two preheats. Irrespective of the selected preheat, earlier saturating DRC groups are associated with the most intense 110 °C TL signal, and the least intense 325 °C TL signal, which corresponds to the main OSL trap. Later saturating DRC groups generally show the opposite trend. There are also trends within other regions of the glow curve and DRC group, such as prominent TL responses at 140–160 °C, 220–240 °C and 390–410 °C. We assessed the effect on the accuracy of equivalent dose (De) estimation using an associated radiocarbon age as an independent cross-check of the OSL ages for the DRC groups. De over- and under-estimates were obtained for some DRC groups. Most notably, grains preheated to 160 °C displayed a pattern of De values which decreased with an increase in D0. We relate this to variable concentrations of charge at the ∼230 °C TL trap prior to regenerative dose OSL measurements. OSL ages for most DRC groups preheated to 260 °C are close to the radiocarbon age, as are those of later saturating DRC groups preheated to 160 °C; the latter DRC groups have the smallest TL signals at ∼230 °C relative to the TL peak at 325 °C. The results of this study suggest that correlations between single-grain De and D0 values can occur due to underlying differences in the TL characteristics of grains with different DRC shapes. In the absence of independent age control and prior to measuring multi-grain aliquots of quartz, we recommend that OSL dating practitioners screen their samples for any single-grain patterns of De as a function of DRC shape, to determine the optimal SAR measurement conditions and data-analysis procedures for De estimation.

Thermoluminescence dosimetry and microstructural characteristics of gamma-irradiated natural flake graphite

Thermoluminescence (TL) and microstructural analysis were conducted on natural flake graphite (NFG) to assess its suitability for radiotherapeutic x-ray dose measurements. The investigations encompassed the examination of TL glow curves, linearity, sensitivity, signal decay, and repeatability. NFG samples were exposed to 60Co gamma radiation doses ranging from 2 Gy to 20 Gy. The microstructure of the irradiated NFG was probed using a 532 nm laser Raman spectrometer. Promisingly, the NFG exhibited remarkable characteristics, including a moderately higher response to dose (R2 of about 96%), increased sensitivity at lower doses, and good repeatability (∼4%). Nevertheless, its fading rate reached about 80% after 14 days of irradiation. Additionally, the NFG intensity ratios of defect (D) to graphite (G), denoted as ID/IG, closely mirrored the oscillatory pattern observed in 50 μm thick graphite sheets and were approximately 1.6 times lower than those of similar graphite sheets with comparable carbon content (about 98% carbon). These findings suggest that NFG holds potential for the development of an affordable, non-hygroscopic, and tissue-equivalent TL dosimeter, with possible applications in the medical field.

Determination of the Kinetic Parameters of Thermoluminescent Glow Curves of Sintered Al2O3 Pills by Three Points Method

The three points analysis method, proposed by Rasheedy, was applied to separate a complex thermoluminescence (TL) glow curve into its individual components and determine, for each component, the kinetic parameters. These are the order of kinetics b, the activation energy E (eV), and the pre-exponential factor S'' (s^-1) associated with the TL glow peaks in sintered pure Al2O3 pills in response to gamma irradiation. The three points analysis method indicated that the glow curve of this material is the superposition of three general-order components, in which the recombination processes predominate over retrapping processes.

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.

Kinetic analysis and dosimetric characteristics of the thermoluminescent glow curve of aquamarine (Be3Al2(SiO3)6:Fe)

Kinetic analysis of the thermoluminescent (TL) glow curve of aquamarine, a cyan variety of beryl (Be3Al2(SiO3)6), is reported. Samples were irradiated at room temperature using a90Sr/90Y β source at a rate of 0.10 Gy-1. Measurements made at 1 °C/s after irradiation from 1 to 100 Gy show a high intensity peak at 75 °C followed by three secondary peaks at 115, 189 and 302 °C respectively. The dose response of the high intensity peak (called the main peak) is linear within the first 20 Gy, but tends towards sub-linearity as the dose is close to 100 Gy. The signal decays with the time delay between irradiation and reading. It decays about 14% of its initial value, 600 s after irradiation. Reproducibility analysis shows that the material reproduces its response under identical experimental conditions with an uncertainty of 0.8% after 10 Gy beta dose irradiation. The kinetic analysis of the TL glow curve was carried out using the curve fitting method. The results show that the main peak follows first order kinetics, its activation energy is of the order of 1 eV and the frequency factor is between 1012 and 1014 s−1, while some secondary peaks follow general order kinetics.

Thermoluminescence dosimetric characteristics and glow curve analysis of Eocene rock salt, the gray halite, mined from Bahadur Khel site, Pakistan

Thermoluminescence (TL) response of naturally occurring Eocene rock salt (Gray halite) is assessed for its potential use as a cost-effective phosphor for dosimetric applications. Natural deposits of the Eocene salt lie on the Himalayan foothills in Pakistan. The grayish color of the halite is due to the intermixing of black bitumen/shale. EDS and ICP-OES techniques are used for the analytical study of the sample. It confirms the presence of Ca, K, Mg, Sr, Zn SO4, Mn, Al, Si and Fe along with the main matrix-NaCl. The Eocene salt is sulfur (S) rich, and potassium (K) poor mineral as compared to the other regional halite. The XRD analysis shows that lattice structure of the halite is composed of two interpenetrating FCC-sublattices of Na and Cl. Cold pressed pellets weighing 40 mg are produced for dosimetric study of the material. Standard gamma source is used for pellet irradiaition. Three different samples of Eocene salt (i.e. rock salt, naturally precipitated salt and refined salt) are prepared. It is observed that, if the material is used as such in its natural form, the dosimetric peak of the glow curve occurs at higher temperature >260 °C. The raw form of rock salt is therefore pre-processed (refined) whereby the major glow peak has shifted onto the dosimetrically significant position at 230 °C. Because of the optimal shape of the glow curve, the refined salt sample is investigated in detail: TL glow curves are acquired from 50 °C to 300 °C, the phosphor reveals a composite glow curve where four peaks are observed at approximate positions of 110 °C (P1), 145 °C (P2), 180 °C (P3) & 230 °C (P4). TL response is studied in the range of 5 mGy to 2 Gy; where a linear/superalinear dose-response behavior is observed for the current material. The Minimum Detectable Dose Limit (MDDL) is measured from the linear region and found to be 0.37 mGy. The first readout results in very low residues <0.005 % and is sufficient to afresh the dosimeter for the next reading. A repeatability test is performed up to 20 identical cycles: the resultant COV, obtained for refined salt sample, is 2.3 % (and 1.5 % in 10 cycles). The irradiated pellets show about 20 % loss of the initial signal for one month fading study. Tm-Tstop method and CGCD techniques are used for kinetic analysis. Kinetic parameters (b, E and s) are estimated from multiple glow curves and found similarities in the results. The results of the preliminary investigations suggest that the pellet prepared from Eocene salt has a potential for use in TL dosimetry.

Photoluminescence and afterglow of Tb3+ doped BaAl2O4

Tb3+ doped BaAl2O4 phosphors (0–9.0 mol%) were prepared through sol–gel combustion method. The crystal structure, morphology, chemical composition, photoluminescence (PL), afterglow and thermoluminescence (TL) glow curve of Tb3+ doped BaAl2O4 were investigated by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, PL spectroscopy, afterglow spectroscopy, and TL dosimetry. Characterizations of the PL and afterglow spectra indicate that both Tb3+ doping species and oxygen vacancies act as the luminescence center of PL whereas only Tb3+ dopant works as the luminescence center of afterglow for Tb3+ doped BaAl2O4. The green afterglow of Tb3+ doped BaAl2O4 lasts for about 214 min at the optimal doping concentration of about 1.0 mol%. The profile of TL glow curve of Tb3+ doped BaAl2O4 heavily depends on the doping concentration, and the evolution of the TL glow curve with doping concentration reveals that doping BaAl2O4 with Tb3+ can significantly modify the distribution of carrier traps in the phosphor. The effects of Tb3+ doping on the PL, afterglow, and TL glow curve of Tb3+ doped BaAl2O4 are discussed in terms of the creation, recombination, and neutralization of defects in BaAl2O4. This work proves that doing with Tb3+ species is a general and robust strategy for endowing BaAl2O4 with highly efficient green afterglow. This “defect engineering” approach enables ultra-long afterglow for Tb3+ doped BaAl2O4 when defect centers in the phosphors are optimized.

Effect of helium ion and gamma irradiation on the TL and OSL properties of Tb-doped LiF nanophosphors

Lithium Fluoride (LiF) stands out as a extensively researched material in Thermally Stimulated Luminescence Dosimetry (TLD). This study specifically delves into nanocrystalline Tb-doped LiF TL dosimeters, synthesized through the co-precipitation method, and evaluates their efficacy under He ion and gamma rays radiation. Morphological examination via transmission electron microscopy has revealed cubic-shaped particles. These particles were subjected to irradiation by 120 keV He ion beams ranging from 1014 to 1016 ions/cm2 and gamma rays ranging from 10 to 1000 Gy, facilitating a comprehensive comparative analysis. Deconvolution of the glow curves enabled the extraction of trapping parameters. Under gamma irradiation, the nanophosphor exhibited a distinctive, intense single TL glow peak centered at 400 K with a minor hump at 512 K, diminishing with increasing doses. Conversely, under He ion irradiation, the nanophosphor displayed a peak at 492 K, accompanied by a slight shoulder around 600 K. Additionally, gamma doses displayed a highly promising response to Optically Stimulated Luminescence (OSL). Fading studies further underscore its suitability for radiation dosimetry applications. The unique characteristics of the TL glow curve, dose-response behaviours, and OSL responses highlight the versatility and effectiveness of these nanophosphors in radiation dosimetry, making significant contributions to advancements in this field.

Beta irradiation-induced thermoluminescence: Glow curve analysis and kinetic parameters in combustion-synthesized undoped Ca4YO(BO3)3

This study examines the thermoluminescent (TL) properties of undoped Ca4YO(BO3)3 phosphor, focusing on how it behaves under a variety of experimental conditions. The IRSL-TL 565 nm was chosen as the appropriate detection filter among various optical detection filter combinations. During the preheating trials conducted at a rate of 2 °C/s, the TL peak exhibited increased intensity, particularly around 200 °C. The experimental outcomes demonstrated a reliable linear relationship (R2 = 0.996 and b = 1.015) in the dose response of undoped preheated Ca4YO(BO3)3 within the range of 1–200 Gy. The investigation encompasses a range of techniques, including the TM-Tstop method, computerized glow curve deconvolution (CGCD) analysis, and theoretical modelling. The application of the TM-Tstop method to samples irradiated with a 5 Gy dose revealed distinct zones on the TM versus Tstop diagram, signifying the presence of at least two discernible components within the TL glow curve, specifically, a single general order kinetics peak and a continuous distribution. The analysis of activation energy versus preheated temperature exhibited a stepwise curve, indicating five trap levels with depths ranging between 1.13 eV and 1.40 eV. The CGCD method also revealed the superposition of at least five distinct TL glow peaks. It was observed that their activation energies were consistent with the Tm-Tstop experiment. Furthermore, the low Figure of Merit (FOM) value of 1.18% indicates high reliability in the goodness-of-fit measure. These findings affirm the reliability and effectiveness of the employed methods in characterizing the TL properties of the Ca4YO(BO3)3 phosphor under investigation. Theoretical models, including the semi-localized transition model, were introduced to explain anomalous observations in TL glow peak intensities and heating rate patterns. While providing a conceptual framework, these models may require adjustments to accurately capture the specific characteristics uncovered through CGCD analysis. As a potential application, the study suggests that the characterized TL properties of Ca4YO(BO3)3 phosphor could be utilized in dosimetric applications, such as radiation dose measurements, owing to its reliable linear response within a broad dose range.

Investigations of swift heavy ion induced thermoluminescence effect, trapping parameter analysis, and density functional theory of MgB4O7: Eu phosphor

The present work reports swift heavy ion (SHI) induced thermoluminescence (TL) dosimetric properties and density functional theory (DFT) studies of Eu doped MgB4O7 phosphor. Comparative investigations of structural, and luminescent properties of MgB4O7:Eu phosphor upon irradiation by 100 MeV Ag7+ and Ni7+ ion beams at the varied fluence range from 1 × 1010 ion/cm2 to 5 × 1012 ion/cm2 are presented systematically. Eu doped MgB4O7 phosphor is prepared by facile hydrothermal method. X-ray diffraction pattern of the material reveals its orthorhombic structure with crystallite size of ∼30 nm. Fourier transform infrared spectroscopy (FTIR) studies demonstrate loss of crystallinity of material after the SHI irradiations. Correlation of stopping powers and projectile range calculations is performed using SRIM software. The investigated photoluminescence properties show emission bands located in the orange-red region with prominent peaks centered at ∼593 nm and ∼625 nm corresponding to 5D0→7F1 and 5D0→7F2 transitions of Eu3+ion. The influence of ion beam fluence on the photoluminescence properties has been explored. Variation in the intensity of the PL peaks without any shift in the peak positions is observed at different ion fluence. The TL glow curve of phosphor exhibits two major dosimetric peaks (a) at 185 °C and 275 °C and (b) at 172 °C and 273 °C upon Ag7+ and Ni7+ ion beam irradiation respectively. The phosphor shows fairly good linear dose response in the range of 1 × 1010 ion/cm2 to 5 × 1012 ion/cm2. Fading measurements reveal 10% and 12% fading for the irradiation of Ag7+ and Ni7+ ions respectively in two months. Trapping parameter calculations of SHI irradiated phosphors are carried out via various TL glow curve analysis methods such as, peak shape method, whole glow peak method, and glow curve deconvolution method. Efficient thermoluminescence properties of MgB4O7:Eu make it a potential phosphor material and promise to provide avenue into swift heavy ion dosimetry applications. DFT computational studies performed to obtain the electronic structure of Eu doped MgB4O7 phosphor support the experimental results of crystal structure, symmetry and electronic structure studies.

Development of Dy3+ doped lithium magnesium borate glass system for thermoluminescence based neutron dosimetry applications

Abstract The manuscript reports the synthesis of Dy3+ incorporated lithium magnesium borate glass by melt quenching technique. FTIR study revealed the presence of both BO3 as well as tetrahedral BO4 units through their characteristic frequencies. Photoluminescence (PL) study of unirradiated samples confirmed the presence of Dy dopant in the ‘+3’ oxidation states from the characteristic emissions at 482, 578, 666 and 716 nm corresponding to 4F9/2 → 6H15/2, 4F9/2 → 6H13/2 and 4F9/2 → 6H11/2, 4F9/2 → 6H9/2 transitions, respectively. Thermal neutron and gamma irradiated PL emission and lifetime characteristics were discussed in details based on the different defect centers. Thermal neutron irradiated TL study showed that the material has a broad and single dosimetry glow peak at about 450 K which showed high fading due to low temperature peak. TL based neutron sensitivity of LMB: Dy3+ was found to be about 37.4 times less than that of standard TLD-100 (LiF: Mg, Ti) powder. The net TL response from about 3 to 83 mSv of neutron dose was found to be linear (Adj. R2 = 0.9994) which is one of the most desirable properties for dosimetry applications. In addition, the TL trap parameters were evaluated using both deconvolution of TL glow curve and peak shape method as suggested by Chen which were found to be matching with each other.

Synthesis and thermoluminescence behavior of novel Sm3+ doped YCa4O(BO3)3 under beta irradiation

This study investigates the luminescent properties and dosimetric potential of YCa4O(BO3)3:0.5%Sm3+ phosphor synthesized via the combustion method. Dose-response investigations unveil a noteworthy linear increment in thermoluminescence (TL) intensity, emphasizing a remarkable linearity spanning a broad dose range from 0.1 to 300 Gy. Unusual heating rate effects are explored, revealing a shift in TL glow curve peak temperature (i.e 200 °C) towards higher temperatures with increasing heating rate. Speculative models, including Kinetic Trapping Effect, Thermal Quenching Compensation, and Defect Activation Energy Changes, are proposed. The study employs the Tmax-Tstop method to identify characterize glow curve peaks, and the Initial Rise method for the low-temperature segment analysis, revealing seven distinct trap levels at various depths within the bandgap. Glow curve deconvolution using the Complex Glow Curve Deconvolution (CGCD) method delineates a multi-peak structure, offering valuable insights into luminescent mechanisms. The model exhibits a Figure of Merit (FOM) of 1.71%, within an acceptable range, affirming its reliability. However, interpretation of the activation energy and frequency factor values suggests intricate site processes, necessitating a nuanced analysis to understand the material's luminescent characteristics. The YCa4O(BO3)3:0.5%Sm3+ phosphor demonstrates promising characteristics for precise dosimetry, with linear dose response, absence of saturation effects, and intriguing heating rate behavior.

Luminescence properties of Ce and Be-doped CaAl12O19 for dosimetric and light-emitting applications

In this study, we reported the sol-gel production of cerium (Ce) and beryllium (Be)-doped calcium aluminate (CaAl12O19) and its luminescence properties for optically stimulated luminescence (OSL) dosimetry and light-emitting applications. Structural, morphological and elemental characteristics of the samples were examined by x-ray diffraction (XRD), Scanning electron microscope (SEM)/energy dispersive spectrum (EDS), x-ray fluorescence (XRF) and Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) techniques. The maximum OSL intensity was achieved with 0.5 and 2% mol concentrations of Ce and Be dopants, respectively. We investigated the OSL and thermoluminescence (TL) properties of Ce and Be-doped CaAl12O19 by measuring energy storage for 24 h, dose-response in the range of 0.1 and 20 Gy, and reusability of the samples for 15 cycles. Photometric properties of the phosphors were investigated by evaluation of CIE chromaticity coordinate (x, y), CCT, and colour purity using its corresponding photoluminescence (PL) emission spectra. We also applied computerized glow curve deconvolution (CGCD), various heating rate methods, and the Tm-Tstop procedure to determine the trap localizations associated with the TL glow curve. The results of this study point out that CaAl12O19 crystals have the potential to be used as OSL dosimetry when appropriate dopants are used. This study may offer new possibilities in radiation dose detection and monitoring.

Synthesis and Thermoluminescence Properties of Undoped Calcium Fluoride (CaF2) Nanoparticles using Co-Precipitation Method

This study investigated the thermoluminescence properties of undoped CaF2 nanoparticles synthesized via co-precipitation with ethanol. X-ray diffraction revealed pure CaF2 nanoparticles with a complete cubic structure and an average crystallite size of 36.5 nm. Scanning electron microscopy confirmed the nanoscale size, averaging 51.23 nm. Electron dispersive spectroscopy analysis showed that the sample mainly consists of Ca and F, with oxygen potentially introducing defects in the crystal structure. Synthesized nanoparticles TL glow curves exposed to 7 mGy of 90Sr beta rays exhibited a prominent peak at 205 oC in thermoluminescence glow curves, likely due to oxygen-induced defects that act as thermoluminescence activators. The thermoluminescence activating energy and the frequency factor of the CaF2 nanoparticles were determined using initial rise methods of approximately 0.83 eV and 5.99 x 10-19, respectively.