THERMOLUMINESCENCE GLOW CURVE PROPERTIES OF TLD-500 DOSIMETER

In this paper, TL characteristics and glow curves of alpha-Al2O3:C dosimeter, known as TLD-500, were analyzed using different methods and softwares. The effect of heating rate (HR) and low dose (from to cGy up to 5o cGy) on TL glow curves of alpha-Al2O3:C chips have been investigated after beta-irradiation. TL kinetic parameters were also calculated by using computerized glow curve deconvolution (CGCD), peak shape (PS), various heating rate (VHR) and three points (TP) methods. Furthermore, using Mathematica software, all TL glow curves of TLD-500 were decomposed in order to compare with the results of other methods and simulated after exposed different beta doses

Effect of Sm(3+)and Mn2+ incorporation on the structure and luminescence characteristics of Zn2SiO4 phosphor

To evaluate the dopant effect precisely, X-ray diffraction (XRD) for structural, scanning electron microscopy (SEM) with energy dispersive x-ray spectroscopy (EDS) analysis for morphological, photoluminescence (PL) and thermoluminescence (TL) characteristics of un-doped, 2.0 mol% Sm3+ doped and 2.0 mol% Sm3+;x mol% Mn2+ (x = 0.5, 1.0, 2.0, 4.0) doped Zn2SiO4 phosphors were tested. PL mechanisms of excitation and emission were discussed together with data on the structure and morphology of the samples. The beta doses from 0.1 to 500 Gy with various steps were applied to observe the glow curve readouts after 200 degrees C preheat at a linear heating rate of 2 degrees C/s from RT to 500 degrees C. Zn2SiO4:2.0%Sm3+;0.5%Mn2+ was chosen for further analysis due to having both the most PL and TL peak area. Various heating rate method was used to determine the kinetic parameters as well as initial rise with T-M-T-stop analysis and computerized glow curve deconvolution methods.Research Fund of Cukurova University, Turkey [FBA2019-11318, FAY-2015-435]All authors thank Dr. M. Ayvacikli and Prof. Dr. N. Can for their support on XRD and PL evaluations. Z.G. Portakal-Ucar would like to thank Dr. J.M. Kalita and Dr. G.S. Polymeris for the valuable discussions on the TL results. The current study is financially supported by the Research Fund of Cukurova University, Turkey (Project Numbers: FBA2019-11318 and FAY-2015-435)

Thermoluminescence study and evaluation of trapping parameters of samarium doped barium silicate phosphor

We report the detailed analysis of thermoluminescence (TL) glow curves and the evaluation of kinetic parameters of Sm3+-incorporated BaSi(2)O(5.)The effect of various heating rates on TL kinetics and glow peak temperatures of Sm3+-doped BaSi2O5 phosphors exposed to beta particle irradiation at room temperature are investigated. The glow curve of the phosphor exposed to beta-irradiation consists of two main peaks with maxima at about 91 degrees C and 193 degrees C and exhibits good linearity between 1 and 10 Gy. The activation energies and frequency factors of trap centers involved in the TL emission were calculated from the TL glow curve of the sample by means of variable heating rate (VHR), repeated initial rise (RIR), and computerized glow-curve deconvolution (CGCD). Analysis of the main dosimetric peak techniques indicate that activation energies (E) and pre-exponential factor (s) vary between 0.93 and 1.72 eV, 10(10) and 10(13) s(-1). It is found that the temperature of the glow peaks shifts toward the higher temperatures and the TL intensity smoothly decreases as the heating rate increases. The behavior of the TL intensities and glow peak temperatures as a function of the heating rate are discussed with regards to thermal quenching.Jazan University [W41-032]This work was supported by the Jazan University [W41-032]

Thermoluminescence properties of beta particle irradiated Ca3Al2O6 phosphor relative to environmental dosimetry

Undoped Ca3Al2O6 phosphor was successfully synthesized through a gel-combustion method using different fuels. It was characterized by X-ray diffraction (XRD) technique and its cubic phase structure was confirmed from XRD pattern. TL data were recorded from room temperature (RT) to 500 degrees C in the heating rate of 2 degrees C/s. The glow curves of Ca3Al2O6 sample exposed to different beta doses (0-200 Gy) exhibited a significant glow peak at about 184 degrees C. The TL intensity of the glow peak exhibited very good linearity between 0.1 and 10 Gy. Following this, it was decreased at higher doses which was referred to this effect as monotonic dose dependence. Initial rise (IR), peak shape (PS), and variable heating rate (VHR) methods were used to estimate trapping parameters. Computerized glow curve deconvolution (CGCD) method via TLAnal software was also applied to estimate the number of peaks and kinetic parameters corresponding to the main glow curve in Ca3Al2O6 sample. The trapping activation energy of the main dosimetric peak was calculated to be around 1.30 eV for all methods. Present findings confirm that Ca3Al2O6 host is a promising candidate for applications in environmental dosimetry as one depicts good TL dose response with adequate sensitivity and linearity

Thermoluminescence properties of annealed natural quartz after beta irradiation

Here we investigated the effects of annealing, heating rate and fading (after annealing at 800 degrees C) on the thermoluminescence (TL) glow curves of natural quartz (NQ). All of the samples were annealed at different temperatures between 100 degrees C and 800 degrees C and then irradiated with a beta dose of about 34 Gray (Gy), in order to determine the effects of annealing treatments on TL peaks of natural quartz. TL glow curves of the samples were recorded. It was observed that the intensities of TL peaks were strongly sensitive to annealing temperatures at 800 degrees C. The heating rate and fading effect of TL peaks of natural quartz were examined for the annealed samples at 800 degrees C for 30 min. It was observed that the intensities of the TL peaks were differently affected from heating rate and fading. Additionally, TL kinetic parameters (activation energy, frequency factor and order of kinetics) of all peaks were determined for annealed samples using a computerized glow curve deconvolution (CGCD) method and Mathematica software. Copyright (C) 2016 John Wiley & Sons, Ltd

Comprehensive study of photoluminescence and cathodoluminescence of Eu and Tb doped Mg2SiO4 prepared via a solid-state reaction technique

We report narrow-band green-red emitting Mg2SiO4 phosphors successfully synthesized through solid-state reaction method, and the cathodoluminescence (CL) and photoluminescence (PL) properties of the samples were investigated in detail. Under electron beam and 275 nm excitation, Mg2SiO4 phosphors doped with various Eu3+ and Tb3+ concentrations in the range of 1 mol % up to 10 mol % exhibit typical green and red emissions, respectively. Tb doped samples were efficiently excited by a low voltage electron beam and UV light, yielding several emission peaks between 370 and 760 nm, and produced a bright green light peaking at 541 nm due to the D-5(4) -> F-7(5) transition. Eu3+ doped samples exhibited CL and PL emission spectra from D-5(0) to F-7(j) manifold transitions of Eu3+. A strong red-light emission peaking at 610 nm also supports the incorporation of Eu3+ ions. A concentration quenching effect was observed and discussed for both phosphors. The optimal doping concentration of Eu3+ and Tb3+ doped phosphors was 7 mol %. In view of the outstanding performance in the PL and CL, the Mg2SiO4:Eu3+, Tb3+ can be considered as a promising green and red phosphor in solid-state lighting applications

Thermoluminescence behaviour of europium doped magnesium silicate after beta exposure

This article presents a detailed analysis of beta ray exposed thermoluminescence response of a series of Eu3+ doped (0.5-10 mol%) Mg2SiO4 nanocrystalline samples successfully synthesized through solid state reaction method. Optimizing the doping concentration of Eu3+ ion in Mg2SiO4 phosphor was found as 3 mol%. Two main peaks were seen at 246 degrees C and 374 degrees C and also low temperature peak at 78 degrees C. The intensities of these peaks were increased linearly with increasing beta absorbed dose. T-m-T-stop method was used to reveal trap levels. Variable heating rate and computerized glow curve deconvolution methods were also used to evaluate the number of peaks and kinetic parameters, namely activation energy and frequency factor. The results of a series of experiments carried out to investigate some fading characteristics of Mg2SiO4:Eu3+ were also presented. The findings suggest that thermoluminescence properties of Mg2SiO4:Eu(3+ )makes this material suitable and promising dosimetric phosphor material for medical applications.Scientific Research Projects of Cukurova UniversityCukurova University [FAY 2015 435]The authors thank the financial support from Scientific Research Projects of Cukurova University FAY 2015 435 project

Comprehensive study of photoluminescence and cathodoluminescence of Eu and Tb doped Mg2SiO4 prepared via a solid-state reaction technique

We report narrow-band green-red emitting Mg2SiO4 phosphors successfully synthesized through solid-state reaction method, and the cathodoluminescence (CL) and photoluminescence (PL) properties of the samples were investigated in detail. Under electron beam and 275 nm excitation, Mg2SiO4 phosphors doped with various Eu3+ and Tb3+ concentrations in the range of 1 mol % up to 10 mol % exhibit typical green and red emissions, respectively. Tb doped samples were efficiently excited by a low voltage electron beam and UV light, yielding several emission peaks between 370 and 760 nm, and produced a bright green light peaking at 541 nm due to the 5D4 7F5 transition. Eu3+ doped samples exhibited CL and PL emission spectra from 5D0 to 7Fj manifold transitions of Eu3+. A strong red-light emission peaking at 610 nm also supports the incorporation of Eu3+ ions. A concentration quenching effect was observed and discussed for both phosphors. The optimal doping concentration of Eu3+ and Tb3+ doped phosphors was 7 mol %. In view of the outstanding performance in the PL and CL, the Mg2SiO4:Eu3+, Tb3+ can be considered as a promising green and red phosphor in solid-state lighting applications

Thermoluminescence of β-particle induced Bern-4M muscovite

Bern-4M muscovite from Switzerland was investigated via X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and thermoluminescence (TL). Muscovite has the theoretical formula KAl2(AlSi3O10)(FOH)2, or (KF)2(Al2O3)3(SiO2)6(H2O). Chemical analysis of the muscovite sample was carried out using EDS for major oxides. The results indicate that muscovite includes oxygen (59.1%), silicon (18.86%), and aluminum (15.22%) as major elements and contains low concentrations of potassium, magnesium, and sodium. In standard muscovites potassium use to be 10% and oxygen 47%, probably the sample was strongly lixiviated before the analysis. The thermoluminescence spectrum exhibits a wide glow peak located at 250 °C with a shoulder peak at high temperature region. Trap depth and frequency factor were calculated using Hoogenstraaten's method and found to be 1.16 eV and 1.4 × 1010 s−1, respectively. Reproducibility test indicated that the values within ±5% were obtained after 15 cycles. The storage time experiments were performed for different time periods up to 1 week for dark fading. © 2020 Elsevier Lt