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We report on the photoluminescence, long persistence luminescence, and thermally and optically stimulated luminescence properties of SrAl2O4:Eu2+,Dy3+ and SrAl2O4:Eu2+,Nd3+ phosphors synthetized by the combustion method and annealed under a carbon atmosphere at 1150 °C for 6 h. XRD indicated the presence of a single monoclinic crystalline phase for both phosphors. After exposure to beta radiation, the phosphors exhibited an intense persistent luminescence lasting more than 220 h. After excitation with 375 nm light the emission spectra depict a broad band peaked at 515 nm, which is the characteristic for Eu2+ emission in SrAl2O4 phosphors, and two weak bands at about 405 and 425 nm. After beta irradiation, the Dy co-doped phosphor exhibits an intense thermoluminescence (TL) with a maximum around 60 °C and a weaker peak at 140 °C. The low temperature TL of the Nd co-doped phosphor consist of three peaks; two well-separated peaks with maxima at about 80 and 160 °C and the third one with the maximum near 50 °C, which becomes evident at doses higher than 10 Gy. Stimulation with IR light of 830 nm releases trapped charges caused by irradiation exposure, generating an intense IR stimulated luminescence (IRSL), which exhibits a typical time decay behavior for continuous wave optically stimulated luminescence. The persistence luminescence and IRSL were related to the release of electrons from the traps responsible for the 60 and 140 °C TL peaks in SrAl2O4:Eu2+,Dy3+ and the 80 and 160 °C TL peaks in SrAl2O4:Eu2+,Nd3+ phosphors, respectively.

The objective of this work was to investigate the thermoluminescence (TL) properties of lanthanide-doped CaSO4 synthesized by co-precipitation for particle temperature sensing applications. Desirable properties for temperature sensing include high TL intensity, stability of the TL signal against light exposure, low room temperature fading, UV emission, and multiple TL peaks over a wide range of temperatures. CaSO4 was synthesized with one or more lanthanides and characterized using x-ray diffraction (XRD), radioluminescence (RL), and TL using both broad-band or wavelength resolved detection. We focused particularly in samples containing blue and UV emitting centers (e.g. Ce3+, Tm3+), because of the possibility of better discriminating the TL emission against the blackbody background emission in the high temperature region of the TL curves. TL emission was observed mostly for trivalent states of the lanthanides (Ce3+, Pr3+, Sm3+, Gd3+, Tb3+, Dy3+ and Tm3+), except in Eu-doped samples, in which both Eu2+ and Eu3+ emissions were observed. A variety of TL peaks was observed with emission from

Strontium titanate (SrTiO3) nanopowders are prepared by ultrasound assisted sonochemical route using Polyethylene glycol as a surfactant. The obtained product is irradiated with 8 MeV electrons with electrons dose strength of 2 kGy, 4 kGy, 6 kGy and 8 kGy. The powder X-ray diffraction studies reveals well indexed cubic structure in both pristine and electron beam irradiated samples. Morphological results evidence the spherical shaped nanopowders. The energy band gap was found to be decrease with increase of electron beam irradiation strength. The photoluminescence emission spectra of pristine and electron beam irradiated samples exhibit defects related peaks at ∼424, 444, 460, 483 and 520 nm. Upon electron beam irradiation, the Commission International de I'Eclairage color coordinates are engineered from deep blue color to cyan color. A single thermoluminescence glow peak is recorded at ∼213 °C in all the electron beam irradiated samples up to given dose range 2 kGy, 4 kGy, 6 kGy and 8 kGy. The trapping parameters (E, s) are calculated by employing various methods. Linear dose response, less fading and high reproducibility of electron beam irradiated SrTiO3 samples broadly indicated its suitability for thermoluminescence dosimetry applications.

The Er3+-activated Ca2SiO4 nanopowders were fabricated via sonochemical method using Epigallocatechin gallate as a bio-surfactant. The X-ray diffraction results reveal that the prepared nanopowders consist of a single phase monoclinic structure. The energy band gap of the prepared samples was estimated and found in the range 4.95–5.18 eV. The photoluminescence emission spectra exhibit intense peaks centered at ∼517, 551, 613 and 662 nm, which were attributed to 2H11/2 → 4I15/2, 4S3/2 → 4I15/2, 4F9/2 → 4I15/2 and 4F9/2(1) → 4I15/2 transitions of Er3+ ions, respectively. The photoluminescence emission intensity increases up to 5 mol % of Er3+ concentration and later diminishes. The decrement of emission intensity with increasing Er3+ concentration was related to a self-quenching of the concentration. The cause behind the concentration quenching was proposed as a dipole–dipole interaction among Er3+ ions. Photometric characterizations of Er3+-doped Ca2SiO4 nanopowders exhibit green light emission with high color purity indicates the present nanopowders were quite useful in the fabrication of cool light emitting diodes. The sensor sensitivity of the Ca2SiO4:Er3+ (5 mol %) nanopowders was found to be ∼0.0624 K−1 at lower temperature 303 K, suggesting suitability for the optical thermometry application. Further, thermoluminescence properties of the prepared samples were extensively investigated. The activation energy and frequency factor of the prepared nanopowders were estimated and obtained values were good agreement with standard thermoluminescence materials, which specify the suitability of the prepared nanopowders in dosimetry applications. The aforementioned results confirm the synthesized nanopowders exhibit excellent photometric, sensor sensitivity and thermoluminescence properties signifying suitability in solid state lighting, optical thermometry and dosimetry applications.

Persistent emission (more than 1.5 h) was observed in Tb3+-doped CaYAl3O7 (CYAM) samples after X-ray or UVC excitation. Thermoluminescent (TL) emission spectra showed that Tb3+ emission is responsible for the TL emission signal, indicating a mechanism with a single recombination and luminescence centre. The shape of TL peaks showed overlap of peaks, and thus more than one trapping centre, and this result was confirmed through Tm x TSTOP analysis. TL measurements as function of doses revealed that the TL peak positions do not change with increasing doses of UVC irradiation, which means that all TL peaks can be well described by first-order kinetics. The initial rise method was used to determine the activation energies, whereas E (eV) x Tstop plot showed a distribution of activation energy ranging from 1.1 to 1.3 eV. These depth traps were assigned to intrinsic defects in the host. Possible mechanisms were discussed considering the 4f ground state of Tb3+ and oxygen vacancies as recombination and trapping centres, respectively.

Photoluminescence (PL), thermoluminescence (TL) emission spectra and TL glow curves of barium yttrium fluoride (BaY2F8 – BaYF), undoped and doped with erbium (Er3+) or praseodymium (Pr3+) were measured to investigate the fundamental absorption (band gap – Eg), the nature of the trapping centers, as well as the electronic transitions of Ln3+ in BaYF host. The band gap energy Eg of BaY2F8 was determined by vacuum ultraviolet (VUV) excitation measurements to be around 11.2 eV. Additionally, the electronic transition from excited states of Ln3+ ions and the exciton state were also identified. TL emission spectra showed that the TL emission of doped samples is related to the Ln3+ ion, indicating that the related host trapping centers are not affected by the new trapping centers originated due the dopant ions. Trap depths were calculated by fitting the glow curves using a first order kinetics model. Host-related trapping centers were attributed to intrinsic defects such as Vk and F centers and the new TL peaks observed for Er and Pr-doped samples was associated to the electrons trapping centers. These results lead us to propose a simple model to explain the origin of the TL emission in BaYF.

Ce- and Eu-doped Ca2MgSi2O7 (CMSM) single crystals were synthesized by the Floating Zone method. From the X-ray diffraction patterns, we confirmed that all the CMSM samples have no impurity phases. Under X-ray irradiation, the Ce- and Eu-doped CMSM samples showed scintillation with a broad emission around 390 nm and 530 nm, respectively. The origin of these emissions was considered to be the 5d-4f transitions of Ce3+ and Eu2+, respectively. The absolute light yield of the Eu-doped CMSM sample was 11,000 ph/MeV evaluated under 241Am γ-ray (59.5 keV). In addition, afterglow properties of the Ce- and Eu-doped samples were consistent with the corresponding thermoluminescence properties.

Stimulated luminescence of novel La2O3 nanophosphors doped with Dy3+ and Eu3+ and co-activated with Li+, prepared by microwave-assisted solution combustion synthesis, was investigated for the very first time. X-ray diffraction results indicated hexagonal La2O3 crystalline phase. Lanthanide and Li+ doping did not affect the La2O3 crystal structure. Scanning electron microscopy images showed nanoparticle morphologies such as plates, rods and irregular shapes. Photoluminescence spectra of La2O3:Dy3+, Li+ exhibited blue and green emission bands due to Dy3+ transitions. For La2O3:Eu3+, Li+, sharp emission lines, corresponding to the optical transitions of Eu3+ were observed. Thermoluminescence glow curve of La2O3:Dy3+, Li+ previously exposed to beta radiation exhibited a prominent glow peak located at ∼46 °C, possibly useful for after-glow or persistent luminescence applications, whereas La2O3:Eu3+, Li+ curve, displayed three intense peaks at ∼50, ∼110 and ∼150 °C. Thermoluminescent signal repeatability and decay curve asymptotic behaviour could place La2O3:Eu3+, Li+ as suitable for medium and high-dose radiation dosimetry applications.

Simple solution combustion route is used for the fabrication of CaZrO3: Sm3+ (1–11 mol %) nanophosphors using Aloe Vera gel as a fuel. The powder X-ray diffraction profiles confirm the pure orthorhombic phase. The granular type particles with non-uniformity in the size is observed. Photoluminescence emission spectra exhibit intense peaks at ∼571, 603, 651 and 708 nm, which are attributed to 4G5/2 → 6H5/2, 4G5/2 → 6H7/2, 4G5/2 → 6H9/2 and 4G5/2 → 6H11/2 transitions of Sm3+ ions, respectively. The photometric properties evident that the prepared samples emit bright orange - red light with 79% color purity. The average correlated color temperature value is found to be ∼3100 K. Thermoluminescence glow curves exhibit a broad, intense peak at ∼148 °C. The highest thermoluminescence intensity is recorded for 5 mol % of Sm3+ doped sample. The thermoluminescence intensity at ∼148 °C is found to increase with increase of γ-dose. The optimized CaZrO3:Sm3+ (5 mol %) nanophosphors used as a luminescent labeling agent for visualization latent fingerprints on various porous and non-porous surfaces under ultraviolet 254 nm and normal light. The obtained results exhibits well defined ridge details with high sensitivity, selectivity, and low background hindrance which showed greater advantages. Extensive fingerprint details, namely level II and III features are clearly revealed. Hence, aforementioned results evident that the optimized sample endorse wide spread of applications, namely solid state lighting, high temperature dosimetry and advanced forensic science fields.

To develop long-afterglow luminescent materials for white LEDs application, a series of Sr1·97MgSi2O7-1.5xNx:0.01Eu2+,0.02Dy3+ (0 ≤ x ≤ 0.49) phosphors were designed. The single-phase samples were confirmed and the introduction of N was verified by the XRD patterns and energy-dispersive X-ray spectrum. The average particle size of the phosphors was determined to be about 4.9 μm. When the N is doped, it has been found the Eu2+ emission intensity decreases gradually, which could be owing to the increasing crystal defects by the nonequivalent substitution between N and O. The excitation spectra reveal that the broad and strong excitation bands from 240 to 450 nm can well match the LED chip. It is interesting that the incorporation of N can improve the afterglow time, which has been interpreted by the thermoluminescence curves. The investigation of the temperature-dependent luminescence indicates a beneficial effect on the thermal stability by doping N in the phosphors.

In this study, the thermoluminescence (TL) characteristics and X-ray radiation response properties of 35CaO–15Al2O3–50B2O3:xTb4O7 (x = 0.25, 0.5, 1.0, 2.0, and 4.0 mol%) glasses were evaluated. These glasses, prepared by a conventional quenching method, were transparent and non-hygroscopic. The TL spectra showed a green band emission (400–600 nm) arising from 4fn–4fn forbidden transitions of the Tb3+ ions. A TL glow peak was observed at 360 K in all the glasses at different Tb concentrations. Among them, the 1.0, 2.0, and 4.0 mol% Tb-doped glasses exhibited excellent linearity over the 1.0 mGy–10 Gy irradiation dose range. The TL peak intensity decreased to ∼60% after 1 h, ∼45% after 24 h and ∼30% after 72 h.

Hierarchical microstructures of ZnAl2O4:Ho3+ (0.25–5 mol %) nanophosphors (NPs) were synthesized via solvothermal route using Epigallocatechin gallate (EGCG) as a bio-surfactant. The effect of EGCG concentration on the morphology was studied in detail. The Powder X-ray diffraction (PXRD) studies confirm the cubic phase of the samples. The photoluminescence (PL) emission spectra exhibit peaks at ∼ 540, 553 and 666 nm were due to transitions 5F4→5I8, 5S2→5I8 and 5F5→5I8 of Ho3+ ions, respectively. Thermoluminescence (TL) properties of ZnAl2O4: Ho3+ (0.25–5 mol %) NPs were studied after exposure of 60Co γ-rays at a warming rate of 6 °Cs−1. The TL intensity was found to increase with γ-dose. The kinetic parameters have been determined using Chen's method from the deconvoluted glow curve. The CIE Chromaticity co-ordinates of all the prepared phosphors were located in the blue region. The above results clearly evident that the optimized Ho3+ activated ZnAl2O4 NPs was a promising single phased phosphor for WLED's and dosimetry applications.

Present study reports the effects of varying concentrations of Pr3+ ions on the optical properties of 10ZnO-5Na2CO3-10Bi2O3-75-xB2O3-xPr6O11 (x = 0.1–1 mol%) glasses prepared through melt-quench technique with an aim to achieve suitable optical gain medium for optoelectronic applications. Minimal changes in the measured density, X-Ray diffractogram and Fourier Transform Infrared spectra of the prepared samples confirmed the stability of the glass structure even after 1 mol% doping of the Pr3+. Bonding nature of Pr3+ ion with surrounding ligands and Judd-Oflet (J-O) intensity parameters of the glasses were determined using optical absorption spectra. The photoemission spectra exhibited reddish orange emission around 605 nm at 445 nm excitation. The calculated color chromaticity with x = 0.5847, y = 0.3701 coordinates for 0.1 mol% of the Pr3+ in the glasses suggests suitable optical gain medium for reddish orange LED applications. Metastable lifetimes of the Pr3+ ion were found-out by exponential fitting to the decay profiles. Lasing parameters of the glasses such as branching ratio, radiative transition probability and stimulated emission cross-section of 1D2→3H4 transition were calculated using JO parameters indicating 0.1 mol% Pr3+-doped glasses suitable for 605 nm solid-state laser applications. The mechanism of energy transfer is determined by applying the Inokuti-Hirayama model and was found to involve a dipole-dipole type of interactions. Thermoluminescence (TL) glow curves of the gamma-ray treated 0.1 mol% Pr3+-doped zinc sodium bismuth borate glasses were de-convoluted using Computerized Glow Curve Deconvolution method to evaluate the energy storage properties of the glasses. The intensity variation of the TL component peak (CP2) at 500 K showed linear behavior up to 3 kG y suggesting application in high dose measurements.

In this work, the thermoluminescence (TL) characterization of pellet-shaped ZnO:Na phosphors synthesized through a controlled chemical reaction followed by thermal annealing at 900 °C in air is reported. X-Ray diffraction patterns reveal ZnO hexagonal zincite structure for the samples, some of which were exposed to beta particle irradiation in the dose range from 0.08 to 2048 Gy in order to study their TL features. The synthesized ZnO:Na samples are more than 200 times more sensitive than ZnO samples synthesized by the same method, and present a 0.02 (1/50) sensitivity relative to the TLD-100 dosimeter.

Large single crystals of Rb2KTiOF5 (RKTF), grown by slow solidification method, were studied (7–400 K) for various types of optical and radiation effects. The optical absorption spectra, the parameters of the Urbach rule at 293 K (σ = 0.24 and E U = 105 meV), the low-temperature reflection spectra (T = 7 K, E = 3.7–22 eV) were determined. The luminescence spectra (1.2–6.2 eV) and luminescence decay kinetics are studied upon excitation by a nanosecond electron beam (PCL), ultraviolet and vacuum ultraviolet light (PL), or X-rays radiation (XRL). PL excitation spectra under selective photoexcitation by synchrotron radiation (E = 3.7–22 eV, T = 7 K), temperature dependences of the intensity of steady-state XRL in different emission bands, as well as thermoluminescence (7–400 K) are studied. In the visible spectral region, we detected three luminescence bands that were attributed to radiative annihilation of intrinsic excitons (2.25 eV), recombination-type luminescence (2.1 eV) and luminescence of higher TiOF5 complexes (1.9 eV). The exponential component with lifetime of about 19 μs was revealed in the PCL decay kinetics at 2.25 eV. The low-energy onset of the intrinsic host absorption E c = 3.55 eV was determined on the basis of the experimental data obtained. Spectra of optical constants were calculated by the Kramers-Kronig method, the energy of the onset of the interband transitions E g = 4.2 eV was determined, and the main peaks of the optical spectra were identified.

Due to their very fast short-wavelength emission, neodymium-doped materials are a subject of current interest as potential scintillators. Although the initial reports regarding neodymium-doped orthophosphates (in crystalline form) and their scintillation properties appeared almost twenty years ago, they remain an interesting class of materials since there is no in-depth understanding of their fundamental scintillation mechanism. In the present research, we focus on the crystalline systems: XPO4:Nd3+, where X = Y, Lu, La, Sc. The pulse height, optical absorption, radioluminescence and photoluminescence spectra were investigated and are reported here for various temperatures from 10 to 350 K. Additionally, results of both low and high temperature thermoluminescence measurements are reported in this communication.

In this Communication the behavior of two types of Gd3Al2Ga3O12:Ce samples under gamma and X-ray excitation is compared. Single crystals of GAGG:1%Ce have been grown by the Czochralski technique, while nanoceramic pills of GAGG:1%Ce have been fabricated by the LTHP sintering from nanocrystalline powders prepared by the Pechini method. The results of pulse height, scintillation time profile, radioluminescence as a function of temperature, and low temperature thermoluminescence measurements, are reported, indicating that monocrystals are still a better choice for scintillator application, nevertheless some of the properties of nanoceramics are indeed promising and there should be a room for improvement.

The oxide MgGa2O4 spinel ceramics doped with Mn2+ ions was synthesized by a solid-state reaction at 1200 °C in air. The activator concentration was equal 0.05 mol% of MnO. Phase purity of the synthesized samples was analyzed by X-ray diffraction technique. This spinel ceramics show efficient green emission in the range from 470 to 550 nm with a maximum at about 505 nm under UV or X-ray excitations, which is due to Mn2+ ions. MgGa2O4: Mn2+ exhibits intense thermoluminescence (TL) and optically stimulated luminescence (OSL) after influence of ionizing radiation. Are complex nature of the TL glow curves is associated with a significant number of structural defects that are responsible for the formation of shallow and deep electron traps. In this work, time-resolved OSL characteristics of the samples exposed to beta particles are reported for the first time. A light from green LED was used for optical stimulation. Obtained TL and OSL results suggest MgGa2O4:Mn2+ as perspective material for further research and possible application in radiation dosimetry.

Mo co-doped Y0.8Gd2.2(Al5-xGax)O12:Ce (x = 2.6 and 3) multicomponent garnet crystals were grown by the micro-pulling down method and the luminescence and scintillation properties were investigated. The temperature dependences of radioluminescence yield and photoluminescence decay time were measured to investigate the temperature stability of these crystals. Under excitation with 662 keV γ rays at room temperature, Y0.8Gd2.2(Al2.4Ga2.6)O12:Ce,Mo shows a higher light yield of 53,800 ph/MeV whereas Y0.8Gd2.2(Al2Ga3)O12:Ce,Mo shows a faster scintillation decay times of 50 ns (56%) + 275 ns (44%). A decrease of radioluminescence yield at low temperature observed in correlation with an appearance of the large thermoluminescence peaks can be attributed to the localization of charge carriers at shallow traps.

Rare earth doped phosphors are widely applied to the numerous fields, such as luminescent paints, white-light emitting devices, photovoltaics, security inks, etc., owing to their inherent properties, such as sharp emission profiles, substantial stoke shifts, and long luminescence life time. Here, green emitting CaZrO3:Tb3+ (x = 1–11 mol %) nanophosphors have been successfully prepared by solution combustion route using Cordia myxa (lasura) leaves extract as fuel. The powder X-ray diffraction patterns shows orthorhombic crystal structure. Surface morphology of the samples showed porous and flakes type with large void spaces. Photoluminescence spectra exhibits a series of sharp peaks in the wavelength range of 475–650 nm, which ascribed to 5D4→7F6-3 transitions of the Tb3+ ions. The Commission Internationale de I'Eclairage chromaticity coordinates are evaluated from the photoluminescence emission spectra and exhibited co-ordinates (0.32, 0.40) located within the plane green region of the diagram. Highest color purity was achieved for 5 mol % of Tb3+ ions doped CaZrO3 nanophosphors with an average correlated color temperature value ~6025 K. Thermoluminescence properties of the prepared nanophosphors exposed with ultraviolet light exhibit two glow peaks at ~166 and 328 °C. A linear and sub-linear responses of the thermoluminescence intensity after ultraviolet light exposure on samples confirms that the samples are more suitable for dosimetry applications. Latent fingerprints are developed using optimized CaZrO3:Tb3+(5 mol %) nanophosphor exhibit high sensitivity and selectivity, high contrast and low background interference on different surfaces. More importantly, the single information encryption strategy was designed and used for high-level anti-counterfeiting. The results clearly indicate that the optimized nanophosphor has great potential for real time applications in white light emitting diodes, dosimetry and advanced forensic applications.

Luminescence and scintillation characteristics of Mg2+-codoped (LuxGd3-x)Al2.4Ga2.6O12:Ce (x = 0.2–0.8) garnet crystals grown by the micro-pulling down method are investigated. The Ce3+ 5d1 → 4f luminescence is blue-shifted with increasing Lu content due to the decrease in crystal field splitting of the 5 d levels. With increasing Lu content, the shortening of scintillation decay time accompanied with a decrease of LY value as measured at room temperature can be explained by thermal ionization of the Ce3+ 5d1 excited state. Co-doping with Mg2+ results in the shortening of scintillation decay time, the reduction of LY value and afterglow intensity. At low temperature the radioluminescence quenching is observed in correlation with large thermoluminescence peaks, which can be attributed to the localization of electrons at intrinsic shallow traps.

The present research has been sponsored by the Latvian Council of Science , Grant No. lzp-2018/1-0361 “Research of luminescence mechanisms and dosimeter properties in prospective nitrides and oxides using TL and OSL methods “; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union's Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 73950 , project CAMART 2, AlN ceramics samples, pure and doped with Y2O3, Eu2O3 and GaN, and produced from the same AlN powder, were studied for photoelectric effect, photoluminescence spectra and kinetics and thermoluminescence under irradiation with UV light from above- and below-bandgap spectral region. Common properties of all studied samples were found, such as presence of the complex UV-Blue and Red emission bands in PL and TL emission due to oxygen-related defects and manganese impurities, correspondingly; a new emission band at 320 nm, which is present in PL and absent in TL emission spectrum and is assigned to an oxygen-related centre; luminescence decay comprised of superposition of exponents of various duration from nanoseconds to hundreds of minutes. Among the studied samples the dopant-related luminescence was observed only in AlN:Eu2O3 at 525 nm. No effect of the dopants on fading rate of the stored TL signal was observed. Such properties of the PL and TL as luminescence intensity and relative contribution of the emission bands manifested by individual samples were explained by influence of the dopant type and ceramics sintering procedure on generation and recharging of the intrinsic and impurity defects. © 2021 The Authors. Published under the CC BY license., Latvian Council of Science , Grant No. lzp-2018/1-0361; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union's Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 73950 , project CAMART 2

The objective of this work is to test an efficient material synthesis method, for the development of thermoluminescence (TL) material using yttrium aluminium garnet. The TL properties of undoped, Ce/Tb/Pr/Eu/Yb/Nd doped Y 3 A l5 O 12 (YAG) polycrystalline material, synthesized by combustion synthesis at low temperature, under ultra-violet (uv) and γ -rays irradiation is reported. The effect of controlled Si codoping is also inspected. The introduction of the doping ions induces changes in the trapping processes and the TL efficiency. The TL signal of Ce doped YAG samples indicates a high sensitivity to uv, γ-ray irradiation. It has been found that there is a prominent enhancement in TL glow peak with Si doping. Trapping parameters of uv irradiated YAG:Ce/Si were calculated from the TL data. The prepared ceramics have found potential application for uv and γ−ray radiation dosimetry purpose.

The purpose of this study is to synthesize Mg(1-x)O:xLi+ (x = 0, 1, 2 and 3 mol%) luminophors using Solution Combustion Synthesis(SCS) and investigate their potential applications in WLEDs and radiation dosimetry. The single phase (cubic) formation of samples is confirmed by Rietveld refinement of XRD data recorded at room temperature. The vibration characteristics are investigated by Fourier transform infrared spectroscopy. The diffuse reflectance spectra are recorded to calculate the values of the energy band gap of pristine and gamma exposed samples. SEM Micrographs reveal the formation of non-uniform shaped grains and a decrease in grain size with an increment in dopant concentration. Photoluminescence (PL) emission spectra exhibit broad bands around ~398 nm and ~485 nm that are ascribed to various defects in the MgO lattice. The influence of concentration on PL intensity indicates that 1 mol% dopant concentration is optimal. The CIE coordinates located in the blue region advocate the suitability of prepared samples for application in WLEDs. The dosimetric properties such as batch homogeneity, dose response and fading along with the influence of different γ-doses and dopant concentration on the TL intensity of γ-exposed luminophors are explored using recorded thermoluminescence (TL) glow curves of all samples. TL glow curves of lithium incorporated MgO at gamma doses of 50–500Gy show peaks around 150ᵒ-180ᵒ C. Besides, a shoulder peak ~300 °C is observed at higher doses > 1 kGy. Fading analysis indicates that maximum fading of ~10% is detected in the first 48 h s after the irradiation with decrement up to 75% on 15th day. The kinetic parameters of sample ML2 are calculated using three different techniques: the peak shape method, initial rise and the Ilich method.

The scintillation characteristics of Lu3-xGdxAl5O12:Ce (x = 1, 1.25, 1.75, 2, and 2.25) garnet crystals were investigated. With increasing Gd content, the Ce3+ 5d1 → 4f luminescence band was red-shifted due to an increase in the crystal field splitting of the 5d levels. In addition, both the light yield value and contribution of fast scintillation component increased. We attribute this effect to the reduced electron trapping effects of shallow traps buried in the bottom of the conduction band, the lower-energy shift of which is due to the increasing Gd content. A decrease of scintillation yield at the lowest temperature region observed for all samples, showing large thermoluminescence peaks in the same temperature range, can be caused by the localization of electrons at shallow traps. Afterglow signals observed at 10 K for all samples after X-rays irradiation can be explained by quantum tunneling of electrons from nearby traps towards the holes captured at the Ce3+ recombination centers.

A novel BaLu2Al2Ga2SiO12:Ce3+ persistent phosphor was designed and synthesized through hetero-valence substituting Ba2+-Si4+ ion pair for Lu3+-Al3+ one in the Lu3Al3Ga2O12. XRD and Rietveld refinement results confirm the garnet typed crystal structure. SEM information shows that the constituent elements are uniformly distributed on the irregular particles. Under 360 or 430 nm excitation, the samples exhibit broad emission bands peaking at 510 nm. The luminescence intensity reaches to the maximum at 6 mol% Ce3+ doping content, and an internal quantum efficiency of 51.2% is achieved. The concentration quenching between Ce3+ ions is mainly originated from exchange interaction. Moreover, the phosphors exhibit bright cyan afterglow for minutes after removing the blue-light excitation source. The persistent luminescence decay process is studied by thermoluminescence spectra. The persistent luminescence mechanism and optical information writing and reading process are also discussed to explore the application in optical information storage.

A series of infrared long persistent phosphor samples of ZnAl2O4: Cr3+ with various doping concentrations of Ge4+ ions were synthesized via a high temperature solid state reaction method. Powder X-ray diffraction, persistent spectra, afterglow decay curves, photoluminescence and isometric thermoluminescence spectra were collected to identify the influence of the Ge4+ ions on the luminescence in the spinel structure. The results define an optimal co-doping of germanium ions (2 mol%) in the ZnAl2O4: Cr3+ can enhance the afterglow time of the phosphor. With the increase of co-doping, the diffraction peaks shift to the shorter angles which confirm a swelling of the crystal cell. Thermoluminescence data emphasise there are modifications from the presence of the Ge ions. The phenomenon that the long-wave emission reaches the maximum value of the spectral spread before the short-wave signal provides interesting insights into the charge transfer process.

Large single crystals of SrMgF4 (SMF), grown by the Bridgman method, were studied (T = 7–350 K, E = 1.2–6.2 eV) for both the pristine unirradiated and irradiated by an electron-beam (Ee = 10 MeV, D = 100–160 kGy, Φmax = 5 × 1015 electrons/cm2) SMF-crystals. The optical absorption spectra at different radiation doses were determined. The luminescence spectra were studied upon excitation with visible/ultraviolet light (PL), or X-ray radiation (XRL). The PL excitation (PLE) spectra under UV-radiation, the temperature dependence curves for the luminescence intensity of steady-state XRL and PL recorded monitoring emission at different energies, as well as low-temperature thermoluminescence were studied. The paper discusses the effect of electron-beam irradiation on the optical and luminescence properties of SMF crystals, the temperature dependence of the luminescence intensity and low-temperature thermoluminescence of irradiated SMF crystals.

The europium ion (Eu3+) activated lithium zirconium phosphate (Li2Zr(PO4)2) phosphor samples have been synthesized by conventional solid state reaction (SSR) method at high temperature. The obtained phosphor samples crystallize in the hexagonal phase with space group R3C. Photoluminescence (PL) excitation and emission spectra have been recorded and optimum concentration was found to be 2 mol%. In the PL spectra of the synthesized phosphors, a characteristic emission peak observed at 594 nm which is ascribed to the magnetic dipole (MD) dominant transition 5D0→7F1. The colorimetric parameters CCT and CIE Ra values are estimated by CIE chromaticity co-ordinates. Judd-Ofelt (J-O) intensity parameters obtained from emission spectra have been used to evaluate the local site symmetry around Eu3+ ions. The J-O parameters have also been used to calculate the radiative transition probability, branching ratio and radiative lifetime. The gain bandwidth, optical gain parameter and stimulated emission cross-section are also investigated. Thermoluminescence (TL) properties of prepared phosphor have been explained in terms of glow curve and kinetic parameters. The synthesized phosphors are expected to be promising candidates for applications as solid state lighting and optical displays.

10BaO–20ZnO–20LiF-(50-x)B2O3-xSm2O3 (x = 0, 0.1, 0.3, 0.5, 0.7, and 1.0 mol %) glasses were synthesized with an objective to examine the γ-radiation-induced defects and Thermoluminescence (TL) characteristics towards potential TL dosimetry application. The addition of 0.1 mol % Sm2O3 to the host glass led to a drastic enhancement (almost two thousand times) in the TL intensity and concentration quenching was seen thereafter. The Sm2O3 concentration and γ-dose for the examination of defects and TL features were optimized to be 0.1 mol % and 3 kGy, respectively. The lack of distinct peaks in the X-Ray Diffraction pattern confirmed the glass amorphous nature. The structural modification after irradiation was conveyed in the optical absorption spectroscopy by the presence of color centers and in Fourier Transform Infrared spectroscopy by the increase in the Non-Bridging Oxygens. The color centers were identified as Non-Bridging Oxygen Hole Center and Boron E ’ -center from the Electron Spin Resonance characterization. The glass manifested a good linear TL response between 0.25 and 3 kGy, high sensitivity, a minimum detection dose of 2 ± 0.2 Gy, reusability and reproducibility after annealing at 523 K for 15 min, Z e f f of 9.6, and trap activation energies between 0.47 and 1.28 eV. The application of the titled glass system as a potential TL dosimeter is proposed for food irradiation, and γ-environment (up to 3 kGy).

Trivalent neodymium ion (Nd3+) activated sodium magnesium borosilicate glasses having composition (60 – x) B2O3–20SiO2 – 10 Na2O – 10 MgO – x Nd2O3 (where x = 0, 0.04, 0.08, 0.12, 0.16, 0.2 mol%) were synthesized by melt quenching method to study the structural, physical, optical and thermoluminescence behaviour. The physical parameters like molar volume, density, molecular weight, average boron-boron separation, field strength, ion concentration, polaron radius, interionic distance, oxygen packing density and optical basicity were obtained. The structural information was acquired through Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). XRD spectra suggested the amorphous nature of present media and FTIR spectra highlighted the bands present in this amorphous media. To study the optical parameters such as direct band gap, indirect band gap, refractive index, optical dielectric constant, reflection loss, dielectric constant, molar refractivity, molar polarizability, metallization, electronic polarizability, oxide ion polarizability, transmission coefficient, energy band gap based metallization criterion, refractive index based metallization criterion, non-linear optical susceptibility, non-linear refractive index and Urbach model, optical absorption spectra was recorded in the range of 190–1100 nm. These glasses were irradiated with gamma rays to study the thermoluminescence glow curve at six different doses such as 50 Gy, 100 Gy, 500 Gy, 1 kGy, 5 kGy and 10 kGy. The trapping or kinetic parameters like frequency factor, activation energy and kinetic order were also studied by using peak shape method. Linear dose response curve indicates that the 59.92 B2O3 – 20 SiO2 – 10 Na2O – 10 MgO – 0.08 Nd2O3 sample can be considered as a potential candidate for radiation dosimetry.

Mg 2+ co-doped (LuGd) 3 (GaAl) 5 O 12 :Ce (LuGAGG:Ce,Mg) multicomponent single crystalline epitaxial garnet films were prepared and their cathodoluminescence (CL) and thermoluminescence (TSL) properties were studied in this paper. The films were prepared using the liquid phase epitaxy from lead-free BaO-B 2 O 3 -BaF 2 flux and their scintillation properties were characterized using the 10 keV collimated e-beam. More specifically, temperature dependent CL intensity, CL emission spectra, CL decay characteristics as well as TSL emission characteristics of the mentioned films were measured. At the highest content of Mg (700 ppm), the CL decay time was as low as 28 ns and the CL afterglow was as low as 0.01% at 1 μs after the e-beam excitation cut-off, which are important parameters for electron detectors in e-beam devices. The CL temperature quenching of the studied films began above room temperature. An increase of Mg concentration to or above 280 ppm quenched the characteristic CL emission of LuGAGG:Ce,Mg. The TSL measurements show that the trap population in studied garnet samples is considerably suppressed. The LuGAGG:Ce,Mg multicomponent single crystalline epitaxial films were evaluated as the perspective fast scintillators for the electron detectors in the e-beam devices.

Optical, radioluminescence (RL) and thermoluminescence (TL) properties of magnesium aluminoborate glasses were evaluated. The samples were synthesized by the conventional melt-quenching technique using an alumina crucible under ambient atmosphere. After polishing, all the samples show good transparency. In photoluminescence, RL and TL, the emission is predominantly due to the 5d-4f transitions of Ce3+ appearing as a broad feature peaking around 300–500 nm, and the decay time constants are affected by concentration quenching but on the typical range for the 5d-4f transitions of Ce3+. TL glow curves are characterized as a single but broad glow peak over 100–300 °C, and the TL intensity monotonically increases with the X-ray dose irradiated over 1–10000 mGy.

Manganese doped Li2B4O7 (LTB) crystals have been studied using luminescence and EPR spectroscopy, extending the investigations for the first time from the X band to the Q band for higher resolution. Mn2+ ions are shown to substitute dominantly at lithium sites charge compensated by a nearby lithium vacancy. Excitation spectra of the Mn2+ ion emission have been studied in the energy range of 2.5–20 eV. Weak excitation bands up to 5.5 eV are ascribed to specific transitions within the same 3d5 electronic configuration according to the Tanabe-Sugano diagram. A doublet of intense excitation bands in the 7–8 eV region is assigned to electronic transitions to the Mn2+ 6D term split by crystal field into two sub-bands. Thermostimulated luminescence (TSL) curves were studied in the temperature range 5–600 K. Based on the EPR studies and the comparison of TSL spectra of irradiated crystals with spectra of photostimulated luminescence, models of TSL processes are proposed. Emission and TSL processes are shown to be strongly influenced by local lattice relaxation and the mobility of Li vacancies participating in complexes with three different charge states of the Mn dopant.

We report the thermoluminescence glow curves of beta irradiated single crystal α-Al2O3:C,Mg after annealing at 700 and 900 °C. A glow curve measured at 1 °C/s from samples irradiated to 1 Gy following annealing at 700 and 900 °C shows a high intensity peak at 163 °C and seven secondary peaks of weaker intensity at 43, 73, 100, 195, 280, 329 and 370 °C. Comparing the position of the peaks in the annealed samples with those in an un-annealed one, it is observed that the peak at 100 °C appears only after annealing at and above 700 °C. Kinetic analysis of this annealing-induced peak was carried out using the initial rise, whole glow peak, peak shape, curve fitting and variable heating rate methods. The order of kinetics of the peak was determined as first order using various methods including the Tm-Tstop technique and the dependence of Tm on irradiation dose. The activation energy of the peak is about 1.01 eV and the frequency factor of the order of 1012 s−1. The peak was found to be affected by thermal quenching in analysis based on change of peak intensity with heating rate. The activation energy of thermal quenching was evaluated as 1.06 ± 0.08 eV. We speculate that the annealing-induced peak is due to formation of a new electron trap after destruction of the F22+(2 Mg) centre when the sample is annealed at 700 °C. The annealing-induced peak fades with storage between irradiation and measurement. It was also concluded that electrons from traps corresponding to secondary peaks get re-trapped at the main electron trap.

Single crystal of pure Lithium Iodide (LiI) has been grown from melt by using the vertical Bridgman technique. Thermoluminescence (TL) Measurements were carried out at 1 K/s following X-ray irradiation. The TL glow curve consists of a dominant peak at (peak-maximum Tm) 393 K and one low temperature peak of weaker intensity at 343 K. The order of kinetics (b), activation energy (E), and the frequency factor (S) for a prominent TL glow peak observed around 393 K for LiI crystals are reported for the first time. The peak shape analysis of the glow peak indicates the kinetics to be of the first order. The value of E is calculated using various standard methods such as initial rise (IR), whole glow peak (WGP), peak shape (PS), computerized glow curve deconvolution (CGCD) and Variable Heating rate (VHR) methods. An average value of 1.06 eV is obtained in this case. In order to validate the obtained parameters, numerically integrated TL glow curve has been generated using experimentally determined kinetic parameters. The effective atomic number (Zeff) for this material was determined and found to be 52. X-ray induced emission spectra of pure LiI single crystal are studied at room temperature and it is found that the sample exhibit sharp emission at 457 nm and broad emission at 650 nm.

The long persistent luminescence, thermoluminescence (TL) and IR stimulated luminescence properties of two orthorhombic strontium aluminates (Sr4Al14O25) co-doped with Eu2+, Dy3+ and Eu2+, Nd3+ exposed to beta radiation is reported. The phosphors were synthesized by the combustion method followed by a post-annealing treatment under a reductive carbon atmosphere. Photoluminescence emission spectra of both phosphors are typical for emission of Eu2+ ions with 7-fold and 10-fold coordination in Sr4Al14025 and consist of the main band at 480 nm and a weak band between 390 and 440 nm. After exposure to beta radiation the Sr4Al14025:Eu2+,Dy3+ phosphor exhibits two strongly overlapped TL peaks at about 70 and 100 °C while the low temperature TL of the Sr4Al14025:Eu2+,Nd3+ phosphor consist of two well separated peaks with maxima at about 60 and 130 °C. Additionally, both phosphors exhibit a weak TL between 180 and 400 °C. The traps responsible for the low temperature TL peaks are the Dy3+ and Nd3+ centers situated in two different Sr sites with 7-fold and 10-fold coordination. The thermal emptying of the Dy and Nd filled traps creates ultra-long intense afterglow, which gradually decays with time and remains detectable after 220 h storage in dark. IR stimulation of beta irradiated phosphors creates intense IR stimulated luminescence, which is related to the release of electrons from the filled Dy and Nd traps.

In this paper, long afterglow luminescent materials CaAl 2 O 4 :Eu 2+ , Nd 3+ and SrAl 2 O 4 :Eu 2+ , Dy 3+ were successfully synthesized by high temperature solid state reaction using the alumina extracted from oil shale ash. The properties of samples were characterized using X-ray diffraction (XRD), X-ray fluorescence (XRF) photoluminescence (PL) spectra, thermoluminescent (TL) curve, long afterglow material optical test system. CaAl 2 O 4 :Eu 2+ , Nd 3+ and SrAl 2 O 4 :Eu 2+ , Dy 3+ prepared with alumina extracted from oil shale ash showed persistent phosphorescence in blue (440 nm) and green (515 nm) with persistence time over 10 h for the blue and 8 h for the green. This result indicates that the alumina extracted from oil shale ash can be used to prepare fluorescent materials. This reuse can not only utilize the oil shale ash rationally but also substantially increased the added-value of oil shale ash.

YPO 4 doped with Bi 3+ and/or Tb 3+ samples were prepared in air. X-ray excited luminescence measurements showed emission from isolated Bi 3+ and Bi-pairs, and also emission from Bi 2+ was observed. Based on the obtained spectroscopic data, the electron binding energies in the ground and excited states of Bi 3+ and Bi 2+ were placed inside the vacuum referred binding energy (VRBE) scheme, and this was used to explain the luminescence of bismuth doped YPO 4 . The VRBE scheme and additional thermoluminescence glow curves show that bismuth can act both as electron and as hole trap in YPO 4 .

The thermoluminescence of beta irradiated K-Mg-Al-Zn fluorophosphate glass is reported. A glow-curve corresponding to 10 Gy measured at 1 °C/s shows two peaks, a weaker-intensity one at 70 °C and a more prominent one at 235 °C, the subject of this report. The main peak was observed to fade with delay between irradiation and measurement and specifically, by 11% in 15 h. Its dose response is superlinear in the dose range 1–190 Gy although the change was linear for the initial 10 Gy. Regarding kinetic analysis, the activation energy of the higher temperature peak was evaluated as 1.31 eV and that of the lower temperature peak was found as 0.47 eV. It was also noted that the main peak is affected by thermal quenching with an activation energy for thermal quenching equal to 1.37 eV. It is proposed that the mechanism associated with the thermoluminescence in K-Mg-Al-Zn fluorophosphate glass is that electrons trapped by the metal cations are released during heating and then recombine with holes at oxygen sites.

Lu3-xAl5O12:Ce optical ceramics (Lu(3-x)AG:Ce, x = 1, 2, 3 and 4 at.%, respectively) with Lu3+ compositions ranging from 1 to 4 at.% below stoichiometry content were fabricated by solid state reaction method and further optimized by an air-annealing process. The effect of Lu3+ deficiency on the optical, luminescence and scintillation properties of such a non-stoichiometric Lu3-xAl5O12:Ce ceramics was investigated. Significant influence in the material densification was found leading to strong changes in the transparency, radioluminescence (RL) and scintillation response of these ceramics. Within the range of 1 4 at.% Lu3+ deficiency, Lu-Al antisite defects were suppressed effectively and the Lu(3-x)AG:Ce ceramics displayed an extremely high RL intensity which reaches similar to 4 times higher than that of the latest commercial LuAG:Ce single crystals while its transparency deteriorated. The microstructure, presence of foreign phases and charge traps acting in scintillation mechanism were also Characterized by means of SEM, back scattered electron imaging and thermoluminescence techniques, respectively. (C) 2016 Elsevier B.V. All rights reserved.

Low-temperature luminescence and thermoluminescence (TL) of BeO:Zn single crystals have been studied in the temperature range of 6–380 K and energy ranges of 1.2–6.5 eV (emission spectra) and 3.7–20 eV (luminescence excitation and reflection spectra). The introduction of zinc impurity ions (0.05 at. %) into BeO host lattice leads to the creation of both the trapped electron and hole centers: Zn + and Zn 2+ O − . These two new centers are responsible for two TL glow peaks at 307 and 145 K with activation energies of 0.96 and 0.40 eV, and two emission bands at 6.0 and 1.9–2.6 eV. The first emission band is attributed to radiative annihilation of the Zn-impurity bound excitons, and the second one is associated with the intracenter electronic transitions in the defect complex comprising zinc impurity ion. The 6.0 eV luminescence center can be excited at 9.6 eV, the low-energy tail of the BeO host absorption, but below the first excitonic maximum (10.45 eV). The 1.9–2.6 eV luminescence center can be excited at the BeO optical transparency band. Both emission bands in BeO:Zn appear in the X-ray induced luminescence spectra at T = 6 K. This indicates that not only these luminescence centers are excited during band-to-band transitions, but they participate in recombination processes as well. The low-temperature ( T 0 = 6 K) TL study of BeO:Zn single crystals was made for the first time. Analysis of the low-temperature TL glow curves allowed us not only to experimentally determine the energy characteristics of the Zn impurity states in BeO:Zn, but reveal an extremely strong influence of the isovalent zinc impurity on fluctuation rearrangement of BeO host lattice. Note, the fluctuation rearrangement of BeO host lattice, which occurs in the temperature range of self-trapped exciton transformation (80–180 K), was previously known only for undoped BeO and BeO crystals with heterovalent impurities [I. N. Ogorodnikov and A. V. Kruzhalov, Proc. SPIE 2967 (1997) 42].

Novel long lasting phosphors SrMg2(PO4)2:Eu2+, SrMg2(PO4)2:Eu2+, Zr4+, SrMg2(PO4)2:Eu2+, Ho3+ and SrMg2(PO4)2:Eu2+, Ho3+, Zr4+ were synthesized by conventional solid-state reaction method. The luminescent properties were systematically characterized by X-ray diffraction, photoluminescent excitation and emission spectra, as well as thermoluminescence spectrum and decay curves. The XRD patterns indicated that the samples belonged to monoclinic phase and co-doping Eu2+, Ho3+ and Zr4+ ions had no effect on the basic crystal structure. These phosphors emitting purplish blue light is related to the characteristic emission of Eu2+. The afterglow time of Eu2+ activated SrMg2(PO4)2 can be greatly enhanced by the co-doping of Ho3+, Zr4+. After the 365 nm UV light excitation source switching off, the Sr0.92Mg1.95(PO4)2:Eu2+0.01, Zr4+0.05, Ho3+0.07 phosphorescence can be observed for more than 1013 s in the limit of light perception of dark-adapted human eyes (0.32 mcd/m2). Different kinds of TL peaks at 423, 448 and 473 K have appeared, and traps densities have increased compared with the Eu2+ single doped SrMg2(PO4)2 phosphor. By analyzing the TL curve the depths of traps were calculated to be 0.846, 0.896 and 0.946 eV, respectively, which suggested that the co-doping of Ho3+, Zr4+ improved the electron storage ability of material. Besides, the mechanism was discussed in this report.

Persistent luminescent properties in Ce3+-Cr3+ codoped Gd3Al5−xGaxO12 garnet (GAGG:Ce-Cr) solid solution have been investigated. The persistent luminescent color is shifted from orange to yellowish green with increasing Ga content because Ce3+: 5d level splitting becomes much weaker. The depth of electron trap introduced by Cr codoping was estimated from the intense thermoluminescence glow peak by the initial rise method. The trap depth decreases from 0.56 eV to 0.29 eV with increasing Ga content. The shift can be explained by downshift of bottom of conduction band. From the persistent luminescence decay curve measurement after ceasing 450 nm blue illumination, the samples with x = 2.5 exhibited the longest persistent luminescence for 405 min until the luminance becomes 2 mcd/m2 in GAGG:Ce-Cr phosphors.

White-light persistent luminescence is of practical interest but is not easy to generate, especially over a longer time. In this paper we present the possibility to generate a white-light persistent emission over a few hours by the doubly-doped La2Hf2O7:Ti,Pr phosphor. Its relevant thermoluminescent properties are presented together with adequate photoluminescence characteristics. The singly-activated versions (with Ti or Pr) of the La2Hf2O7 host were also fabricated and characterized for comparison and better understanding the properties of La2Hf2O7:Ti,Pr. Thermoluminescence of all those phosphors showed strong activator-concentration dependence. When the activator contents exceeded 0.1mol% the thermoluminescence intensity lessened quickly and the persistent luminescence intensity and duration got reduced adequately. In La2Hf2O7:0.1%Ti,0.1%Pr both activators contributed to strong thermoluminescence peaking at around 115 °C and resulting from traps showing some distribution of depths. After charging, these traps served as reservoir of energy for white persistent luminescence generated by both Ti and Pr activators and lasting a few hours.

The current work presents a study of the thermoluminescence (TL) properties of glow curves obtained from lithium borate glass samples doped with different concentrations of dysprosium (Dy). The first part of the study is aimed to analyse the TL glow curves, obtained from the glass samples irradiated with beta-particles, to determine the number of composing TL peaks and to extract the kinetic parameters of the samples using different methods. The second part is dedicated to characterizing the TL dosimetric properties of the individual TL peaks composing the recorded TL glow curves. The analysis has shown that the glow curves corresponding to the glass samples doped with different concentrations of Dy compose of five overlapping TL peaks with trap depths ranging from 0.733 to 1.289 eV. The kinetic parameters obtained from the different methods agree to good accuracy.

At the doping level of 1 mol%, Tb3+ doped CaAl2O4 (Tb–doped CaAl2O4) nanocrystals were synthesized via the sol–gel combustion technique. Green afterglow was recorded for the as–prepared Tb–doped CaAl2O4. The effects of subsequent annealing on the green afterglow of Tb–doped CaAl2O4 were investigated by means of X–ray diffractometry, scanning electron microscopy, transmission electron microscopy, photoluminescence spectroscopy, afterglow spectroscopy, and thermoluminescence dosimetry, respectively. Both the intensity and duration of the afterglow of Tb–doped CaAl2O4 are found to decrease with the increase in the annealing temperature when annealing temperature is lower than 600 °C. Afterglow of Tb–doped CaAl2O4 is completely quenched as annealing temperature is over 700 °C. In combination with annealing temperature dependent photoluminescence and thermoluminescence of Tb–doped CaAl2O4, our results indicate that the degradation of the afterglow can be linked to the oxidation of Tb3+ into Tb4+ at high annealing temperatures.

Photoluminescence, scintillation and thermoluminescence properties of undoped and Ce-doped SrLaAl3O7 crystals grown using the optical Floating Zone technique were examined. An intense broad emission peak at 400 nm are observed from photoluminescence excitation-emission maps and scintillation spectra of the Ce-doped SrLaAl3O7 crystals, with the origin is ascribed to the 5d-4f transitions of Ce3+. The primary decay of the Ce-doped and undoped SrLaAl3O7 crystals are attributable to the Ce3+ ions and intrinsic luminescence, respectively. The 3.0% Ce-doped SrLaAl3O7 crystal shows the highest light yield of 760 ph/5.5 MeV-α among the investigated samples based on pulse height analysis under α-rays excitation from 241Am.

Calcium borate chlorides (Ca2BO3Cl) with different concentrations of Dy3+ were fabricated by the conventional solid-state reaction with an aim to develop themoluminescent materials for radiation dosimetry, and their scintillation and thermally-stimulated luminescence (TSL) properties were evaluated systematically. Several scintillation peaks at approximately 485, 580 and 675 nm due to the 4f-4f transitions of Dy3+ appeared in the Dy3+-doped Ca2BO3Cl, and the 1.0% Dy3+-doped Ca2BO3Cl showed the highest scintillation intensity. In the temporal scintillation profiles, the decay time constants of the Dy3+-doped Ca2BO3Cl were about 0.6 ms, which was a typical value for the 4f-4f transitions of Dy3+. Furthermore, the Dy3+-doped Ca2BO3Cl showed efficient TSL with glow peaks at 110 and 250 °C originating from the 4f-4f transitions of Dy3+. Among the sample investigated, the 1.0% Dy3+-doped Ca2BO3Cl exhibited the highest TSL intensity, and the linear dose response of the TSL glow peak at 250 °C was confirmed to be in the dose range from 0.1 to 100 mGy for the 1.0% Dy3+-doped Ca2BO3Cl.

The non-hygroscopic crystal of TlAlF4 was grown by self seeded vertical Bridgman technique. The crystalline phase was confirmed through powder X-ray diffraction measurement and compared with reference data. The effective atomic number (Zeff) of the TlAlF4 compound was calculated about 70.77. The X-ray induced emission spectrum having a very strong luminescence band at 390 nm. Thermally stimulated luminescence (TSL) glow curve measurement shows the peak maximum at 430 K. The kinetic parameters for the main TSL peak were studied using various standard methods. The mean activation energy (E) is calculated to be 0.93 eV and the frequency factor is 4.79 × 1011 s−1. The dose response of the sample was studied using X-ray exited luminescence and TSL glow curves. The sample shows good linearity for measured dose range from 17 to 50 R/min. Thermal fading of the sample was checked over a long period of time and also the reusability of the sample was examined. The main TSL peak at high temperature with high sensitivity to ionizing radiation, good consistency in reusability of TSL signals, linear dose response against delivered X-ray doses in a wide dose range and moderate fading effect are some desirable properties of TlAlF4 crystal for considering radiation dosimetric applications.