Single Thermoluminescence Glow Peak Research Articles

Structural and Thermal Properties of a Selected Host Crystal Lattice: Exploration of Inherent Possibilities

Host Ba2MgSi2O7 phosphor was successfully prepared via low temperature combustion synthesis route. The phase identification of the prepared phosphor was done with the help of powder XRD technique. The XRD pattern of the phosphor revealed its monoclinic crystal symmetry with a space group C2/c. The XRD pattern have well clarified with JCPDS PDF card no. #23-0842. The average crystallite size was calculated as 42nm and crystal lattice strain size calculated as 0.24, respectively. It is acquired that the sample UV exposed for 15min gives optimum TL intensity at 112.190C temperature and displays single TL glow peak. On the basis of TL glow curve, it can be suggested that the Ba2MgSi2O7 (BMS) phosphor is an efficient host lattice but not a better TL phosphor. In our present study, we have discussed on the XRD, FESEM and thermo-luminescence (TL) characteristics as well as different kinetic parameters of this phosphor.

Thermoluminescence dosimetry properties and kinetic analysis of K3 Ca2 (SO4 )3 F:Dy3+ phosphor.

A trivalent Dy3+ -activated K3 Ca2 (SO4 )3 F fluoride-based phosphor was synthesized using a solid-state reaction method and characterized for its thermoluminescence (TL) application. The crystal structure and surface morphology of the as-synthesized material was analyzed using X-ray diffraction and scanning electron microscopy. A series of the K3 Ca2 (SO4 )3 F:Dy3+ phosphor was irradiated using γ-rays from a 60 Co source and TL glow curves were recorded using a Nucleonix 1009I TL reader. The glow curve of the prepared phosphor showed a prominent single peak at 278°C. TL characteristics were maximum intensity at 1mol% of Dy3+ ion with a single TL glow peak. The TL glow curve revealed linearity with increase in exposure dose range from 0.1kGy to 3.0kGy. Theoretical analysis of the TL glow curve of the γ-ray-irradiated sample was carried out using a computerized glow curve deconvolution method and trapping parameters such as activation energy and frequency factor were calculated using the initial rise method and Ilich's method. The synthesized Dy3+ -doped K3 Ca2 (SO4 )3 phosphor revealed excellent TL properties and was found to be a potential candidate for dosimetric applications.

Investigating thermoluminescence properties of Na14Al12Si13O51:Dy3+ phosphor for oxygen ion beam exposure

The Na14Al12Si13O51: Dy3+ phosphor is synthesized by combustion method and prepared sample was characterized by X-ray Diffraction, SEM, FT-IR and Thermoluminescence (TL) techniques. TL characteristics show the quenching at 3 mol% of Dy3+ ion activated Na14Al12Si13O51: Dy3+ phosphor with single TL glow peak 154 °C at higher temperature. Prepared phosphor material was irradiated oxygen ion beam at different fluences range from 5 × 1010 to 1 × 1014 ions/cm2. Chens peak method and computerized glow curve deconvolutation method was used to evaluate the trapping parameters namely, activation energy, frequency factor, kinetic order associated with the main glow curve in Na14Al12Si13O51: Dy3+ phosphor after irradiation..

Thermoluminescence studies of Dy3+-doped calcium barium orthosilicate codoped with Li+ ion

Calcium barium orthosilicate (CaBaSiO4) phosphors having different concentrations of Dy3+ were prepared by solid-state reaction method, and phase structure of the sample was identified by X-ray diffraction (XRD) characterization. It is observed that the XRD pattern matched well with JCPDS file No. 48-0210. Thermoluminescence (TL) of the UV-irradiated (254 nm) samples was recorded using routine TL set-up Nucleonix TLD reader with constant heating rate 5 °C s−1. It is found that the sample containing 1 mol% of Dy3+ and exposed for 27 min gives optimum TL intensity at 130.14 °C and shows single TL glow peak. It order to examine the effect of charge compensator ion, Li+ ions are introduced and it is found the incorporation of charge compensator enhances the TL output. Samples having 1 mol% of Dy3+ and 6 mol% of Li+ exposed for 30 min to UV exposure show maximum intensity at 118 °C. It is also observed that temperature corresponding to TL peak varies with varying Li concentration (ranging from 105.76 to 123.88 °C). Samples having 1 mol% of Dy3+ and 6 mol% of Li+ exposed for 30 min to UV exposure were selected for further studies, such as activation energy, order of kinetics and frequency factor, and all these parameters were evaluated using peak shape method.

New handling of thermoluminescence glow curve deconvolution expressions for different kinetic orders based on OTOR model

The exact equations of the thermoluminescence (TL) glow curve deconvolution that describe the intensity of a single TL glow peak of different order kinetics, which are obtained from the one trap-one recombination (OTOR) level model, are considered. The reformulation of the expressions of the intensities of TL glow peaks in terms of the peak intensity IM, peak position TM, and the activation energy ∈, for each order of kinetics are achieved. The authors developed a MATLAB computer code, which utilizes the obtained equations, to computationally deconvolute the TL glow curves. The code is used to investigate the reference glow curves of the GLOCANIN program. The obtained results agree with those previously reported by the GLOCANIN project with better values of the figure of merits FOM. The considerations of the obtained equations show promising trends to understand a peak formation for different order kinetics that belong to the OTOR level model.

Ultrasound assisted fabrication of SrTiO3 nanopowders: Effect of electron beam induced structural and luminescence properties for solid state lightning and high temperature dosimetry applications

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.

Combustion synthesis and luminescence studies of Eu (III) activated LiBaBO3 inorganic phosphor

This work offered study the rare earth doped LiBaBO3 phosphor to reveal the luminescence properties in this material. X-Ray diffraction is used to confirm the crystal structure of this material made by solution combustion synthesis route. A Photoluminescence (PL) measurement shows the phosphor exhibited intense emission at 592nm and 615nm respectively corresponding to 5D0→7F1 and 5D0→7F2 transitions of Eu3+ on excitation with optimum 394nm wavelengths. The remaining excitation peaks at 381 and 465nm with broad band 200–310nm are also shown in the excitation spectra. Varying the irradiation dose of gamma radiation as well as rare earth activator quantity, its thermoluminescence (TL) spectra is measured. A single TL glow peak is obtained at 170°C with a shoulder around 266°C for the heating rate of 5°C/s a. After deconvolution, activation energy and frequency factors are calculated for two peaks P1 and P2. The linear dose response is sketch graphically which prove this phosphor to be useful in the category of new dosimetry materials.

Plant latex mediated green synthesis of ZnAl2O4:Dy3+ (1–9mol%) nanophosphor for white light generation

Abstract ZnAl2O4:Dy3+ (1–9 mol%) nanophosphors were synthesized by a simple, cost effective and environmental friendly route using Euphorbia tirucalli plant latex. The structural properties and morphological features of the phosphors were well studied by PXRD, FTIR, SEM and TEM measurements. The luminescent properties of ZnAl2O4:Dy3+ (1–9 mol%) nanophosphors were investigated from the excitation and emission spectra. The phosphor performance was evaluated by color co-ordinates. The values were well located in the near white region as a result it was highly useful for the fabrication of green component in WLEDs. The average particle size was found to be ∼9–18 nm and same was confirmed by TEM and Scherrer’s method. The highest photoluminescence (PL) and thermoluminescence (TL) intensity was obtained to be ∼7 mol% Dy3+ concentration. A single TL glow peak was recorded at 172 °C at a warming rate of 2.5 °Cs−1. The intensity at 172 °C peak increases linearly up to 1 kGy and after that it diminishes. PL intensity was studied with different plant latex concentration (2–8 ml) and highest PL intensity was recorded for ∼ 8 ml. The optimized phosphor showed good reusability, low fading and wide range of linearity with γ-dose hence the phosphor was quite useful in radiation dosimetry.

Glow-curve de-convolution analysis of TL glow-curve from constant temperature hot gas TLD readers

Abstract The present work attempts the generalization of the computerized glow-curves de-convolution (CGCD) analysis of glow-curve received under an exponential heating function (EHF) used in stable temperature hot gas thermoluminescence (TL) readers. The analysis is based on single TL glow-peak analytical expressions derived for the EHF cases. A special normalization procedure is suggested which allows the deconvolution of very different glow-curves using the same set of the initial parameters during the CGCD analysis. More than two hundreds of glow-curves corresponding to TL measurements for dose response, for quality control, for low TL statistics, for background and finally glow-curves with undesired spurious signals. The results show that the CGCD analysis, which is widely used in the case of linear heating, can be used and be equally effective for the case of EHF as well.

Influence of Pulling Rates on the Thermoluminescence and Optically Stimulated Luminescence of α-Al2O3:C Crystals Grown by the Edge-Defined, Film-Fed Growth Technique

In this work, α-Al2O3:C crystals were grown by the edge-defined, film-fed growth method with different pulling rates. The influence of pulling rate on the optical, thermoluminescence (TL), and optically stimulated luminescence (OSL) properties of the as-grown α-Al2O3:C crystals was investigated. All the α-Al2O3:C crystals grown with different pulling rates show a single TL glow peak and an invariable blue emission band at 415 nm. With an increasing pulling rate in the 0.1–0.7 mm/min range, the absorption coefficient of optical absorption bands at 206 and 256 nm increased, the TL and OSL dose response improved, the TL peak shifted to higher temperatures, and the OSL decay rate increased. When the pulling rate is increased to 1 mm/min, the absorption coefficients of the bands at 206 and 256 nm, the TL temperature and intensity, the OSL intensity, and the decay rate declined. The TL and OSL dose response of the as-grown α-Al2O3:C crystals shows a linear–sublinear saturation characteristic. The pulling rates almost show no influence on the crystals' saturation dose. The α-Al2O3:C crystal grown with the pulling rate of 0.7 mm/min shows the best TL and OSL properties.

Thermoluminescence under an exponential heating function: II. Glow-curve deconvolution of experimental glow-curves

Thermoluminescence (TL) glow-curves measured using an exponential heating function (EHF) in constant temperature hot gas readers, cannot be analysed using the existing single TL glow-peak equations derived assuming a linear heating rate. In the present work single TL glow-peak equations, which were recently derived assuming an EHF, are used to perform a computerized glow-curve deconvolution analysis of experimental glow-curves measured using a stable temperature hot gas reader. Glow-curves of the most commonly used dosimetric material LiF:Mg, Ti were analysed using the first order kinetics glow-peak equations. The glow-curves were analysed for samples that were pre-irradiation annealed at 400 °C for 1 h and 100 °C for 2 h, with and without a post-irradiation annealing at 80 °C for 1 h. TL glow-peak equations of the general order kinetics were used to analyse experimental glow-curves of the dosimetric material Li2B4O7 : Mn, Si. The results showed that the recently derived TL equations are very efficient for analysing glow-curves measured using stable temperature hot gas readers.

Effect of sodium doping on thermoluminescence and optical properties of barium borate (BaB 2O 4) single crystals

Thermoluminescence (TL) emission from undoped and sodium doped α- and β-BaB 2O 4 (BBO) crystals has been investigated. A single TL glow peak is observed for the undoped crystals of both phases. The glow peak temperatures found for α- and β-BBO crystals over the temperature range 35–300°C are 104 and 80°C, respectively. The presence of minute amount of sodium ions in the lattice gives rise to a glow peak around 200°C. For impurity concentrations higher than 0.02% (by wt), additional glow peaks around 123 and 240°C are also observed. The ratio of the TL intensities corresponding to the first and 200°C peaks is observed to increase with impurity concentration. This fact provides an easy and sensitive method of detecting the presence of sodium ions in BBO lattice. The results also show that sodium ions go substitutionally into the lattice and act as charge traps. The optical absorption in the ultra violet region and the crystal hardness towards ionizing radiations are found to be adversely affected by the presence of this impurity.