Thermoluminescence Glow Peak Research Articles

HCl-doped poly (para-nitro aniline-co-para-toluidine) thin film as a gamma ray dosimeter

A semiconductor copolymer, HCl doped poly (para-nitro aniline-co-para-toluidine) [DPPNPT] was prepared by oxidative polymerization route in an acidic medium. The structural properties of the copolymer were characterized by several techniques. Physical vapor deposition technique was used for fabrication of the copolymer thin film [DPPNPT]TF of 100 nm thickness. Material studio 7.0 was calculated with the density functional theory (DFT), geometrical trials including the highest molecular orbits (HOMOs), the lowest unoccupied molecular orbitals (LIMOs), and the other active parameters were obtained. The optical parameters have demonstrated that the thin film has a high absorption range of 2 to 6 eV. Dosimetric properties are considered as another utilization of DPPNPT thin film. Thermoluminescence (TL) properties such as glow curves, different gamma doses response, and dose fading nature were tested. Thermoluminescence examinations of DPPNPT gamma-irradiated showed a single strong TL glow peak located at 350°C. Three unresoluted glow peaks of the [DPPNPT]TF films after gamma irradiation have been obtained. A linear correlation was obtained in the response curve start with 0.01Gy and extended to 2Gy. The total integral value of the TL signal showed a fixation through one month of storage of the DPPNPT compound. TL kinetics in deep traps were used to calculate resolute peaks activation energies. Based on obtained results the [DPPNPT]TF films are a good candidate for detection and monitoring personal gamma-ray doses.

Effect of Gd3+ substituted Cadmium silicate nanophosphor for dosimetric applications

The Gd3+ substituted CdSiO3 nanophosphors (1–9 mol %) have been synthesized by using solution combustion (SC) method. Phosphors have been well reported by powder X-ray diffraction (PXRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR) and UV–Visible spectroscopy. PXRD patterns reveal monoclinic CdSiO3 phase which can be obtained for calcining the samples at 800 °C for 2 h and average size of the samples is (22–42) nm as calculated by Scherer's formula and W–H plots. SEM micrographs show that crystallites are of agglomerated and irregular in shape. The band gap was evaluated by Wod and Tauc method is in the range of (5.18–5.35) eV. A fine determined single Thermoluminescence (TL) glow peak at 138 °C was verified for all the UV exposed models. So prepared nanomaterial's can used in nano-radiation dosimeters.

Optical, scintillation and thermoluminescent properties of Eu2O3-doped K2O–La2O3–Ga2O3 glasses

Glasses are promising functional materials as phosphors with an aim to use in radiation measurements because of easy shaping, low fabrication cost and large volume fabrication possibility. In this study, Eu3+-activated gallate glasses having glass compositions of 20K2O–11La2O3–(69−x)Ga2O3–xEu2O3 (x = 0.1–1.0) were synthesized, and their photoluminescence, scintillation and thermoluminescent characteristics were investigated. Clear luminescence peaks at around 574, 591, 614, 653 nm ascribed to the electronic 4f-4f transitions of Eu3+ appeared when the Eu2O3-doped gallate glasses were irradiated by visible light and high energy X-ray. The photoluminescence and scintillation intensities of the 0.5% Eu2O3-doped gallate glass were found to be the highest. Furthermore, a thermoluminescent glow peak appeared at around 90 °C in the glow curve. The 0.1% Eu2O3-doped gallate glass showed the highest glow peak intensity unlike photoluminescence and X-ray induced scintillation spectra, suggesting that the Eu2O3-doped gallate glasses showed a complimentary relationship between scintillation and thermoluminescent intensities.

Synthesis, optical and thermoluminescence properties of thulium-doped KMgF3 fluoroperovskite

KMgF3 fluoroperovskite doped with thulium at different concentrations were synthesized by the solid-state reaction method. The phase composition and the thermal stability up to 600 °C of the polycrystals were analyzed by X-ray diffraction and thermogravimetric analysis, respectively. The KMgF3 at 1.0 mol% of Tm polycrystals showed the best thermal stability and did not present another phase. The gamma radiation (0.1–10 kGy) effect in thulium-doped KMgF3 produced the F color centers, and their aggregates such as F2, and F3 centers. The F centers, and the potassium vacancies (VK−) in the fluoroperosvkites were analyzed by the optical absorption and emission measurements. Optical absorption at 275 nm and 443 nm were assigned to F and F2, respectively, in undoped KMgF3. Tm-doped fluoroperovskite shows the optical absorption bands at 277, 393, 432, and 577 nm, which were ascribed to the F, F3, F2 and VK− centers, respectively. When the F band for undoped polycrystals was excited at 275 nm, a clear emission associated with F2 and F3 centers was observed. In the case of Tm-doped, an enhancement of the blue emission at 457 nm occurred and a UV band (354 nm) was observed upon exciting the F band. The blue emission of thulium was overlapped with the F3 color center band. The emission bands at 457 and 354 nm were ascribed to 1D2 - 3F4 and 1D2 - 3H6 transitions of Tm in KMgF3. The optical absorption and glow curves were investigated too. The glow curves were assisted by the color centers, vacancies, and thulium impurity. Thermal bleaching shows that the F center was the main participant to give rise to the TL intensity of the glow curves. Thulium acts as a deep electron trap in the bandgap of the KMgF3 fluoroperovskites forming TL peak at the higher temperature, from 430 to 408 °C. The absorption, emission, and thermoluminescence glow peaks of the undoped and Tm-doped KMgF3 were compared.

THE LUMINESCENCE AND THERMOLUMINESCENCE STUDIES OF Nd3+ DOPED Sr2SiO4

Sr2SiO4:%3Nd3+ was synthesized and its structural characterization was made via XRD technique. The results indicated that Sr2SiO4:%3Nd3+ had Pmma (62) space group (PDF: 00-039-1256) in the orthorhombic crystal system. Luminescence and thermoluminescence (TL) properties of Sr2SiO4:%3Nd3 was investigated in detail. Computerized glow curve deconvolution methods was used for to determine the kinetic properties of Sr2SiO4:%3Nd3+. The TL results showed that Sr2SiO4:Nd3+ consisted of seven TL glow peaks.

Characterization of a promising luminescence-based graphite radiation dosimeter

Characterization has been undertaken of the thermoluminescence (TL) properties of 0.3 mm polymer pencil lead graphite (PPLG). For 60Co gamma irradiation doses from 0.5 Gy up to 20 Gy readout data have been taken at different heating rates, from 2 to 15 °C s−1, linear TL responses with radiation dose being found, also with a greater degree of sensitivity at the lowest dose. Estimation has been made of the principal trap parameters of the PPLG, use being made of the variable heating rate method via the Hoogenstraaten, Booth - Bohun – Parfianovitch and Two Point Two Heating Rate techniques. Among the trap parameters are included the order of kinetics, activation energy, the frequency factor, and the initial concentration of trapped electrons. Also determined are relations that allow estimation of the temperature lag between the heating element and that of the sample. The stability of TL signal has been examined at peak temperatures with the lifetime of the TL glow peak calculated. Structural alterations of the irradiated PPLGs have been observed via Raman and Photoluminescence (PL) spectroscopy, also via X-ray diffraction (XRD), providing information on physical parameters relating to the defects participating in the luminescence process. The results indicate 0.3 mm PPLG to offer promising potential as a new generation of radiation dosimeter, including for medical radiation applications.

Thermoluminescence in Eu doped NaLi2PO4TLD nanophosphor: Effect of particle size on TL characteristics

We report the thermoluminescence of Eu-doped NaLi2PO4 synthesized by solid state diffusion method. Formation of the material was confirmed by powder X-ray diffraction (PXRD) technique. Broadening of the PXRD peaks and field emission scanning microscope (FESEM) images were used for determining its particle size(s). Thermoluminescence (TL) characteristics were studied to see the effect of particle size after irradiating with γ -rays from 60Co source for wide-range (10 Gy-100 kGy) of doses. It was observed that not only TL sensitivity but also glow curve structure depends on particle size of the material. Glow curves were further deconvoluted using computerized glow curve deconvolution (CGCD) technique (after confirming the number of peaks using Tm-Tstop method) to study trapping parameters. TL glow curves mainly consist of four peaks appearing in the temperature ranges of 378–385, 426–435, 447–458 and 497–506 K. The shifts in the TL glow peak temperatures and the changes in glow curve structures can be attributed to the reorganization of local impurity levels (electron traps/luminescence centers) on widening of the band gap with reducing particle size. There can also be the effect of stress on glow curves developed due to crushing. Widening of the dose response with reducing particle size, easy method of synthesis, high sensitivity, low fading, good chemical stability, etc. make this TLD nanophosphor a good candidate for radiation dosimetry using TL.

Studies of thermoluminescence kinetic parameters of polymer pencil lead graphite under photon exposures

This study analysed thermoluminescence (TL) glow curves of the polymer pencil lead graphite (PPLG) due to its potential applications in radiation dosimetry. The TL glow curves provide information on the physical parameters of the defects participating in luminescence process. The glow curves for different diameters PPLG samples were obtained with varying temperature from 50 to 300 °C, at a fixed heating rate of 10 °Cs−1. A number of methods (initial rise, peak shape and curve fitting) were used to fit the TL glow peaks of the PPLG samples obtained under photon dose of 200 Gy. From the fitted TL signals, the trap parameters such as the order of kinetics, the activation energy, the frequency factor, etc. for the individual peaks were numerically determined. The lifetimes of TL process were calculated assuming the first-order kinetics. The results are compared among the different methods adopted in this study. Implications about the possible results in glow curve deconvolution are discussed.

THREE-POINT AREA METHOD FOR THERMOLUMINESCENCE GLOW CURVE ANALYSIS AND ITS APPLICATION TO THE GLOW PEAK OF K2SRP2O7:PR.

A method has been proposed to evaluate the kinetic parameters, viz. activation energy ($E$) and order of kinetics ($b$) from a single or isolated thermoluminescence (TL) glow peak. Along with the area under the entire curve, this method uses a set of three arbitrary data points and calculates the partial area under the curve from each point to the endpoint. In this way, the entire information associated with the curve is used and the method is named as 'Three-Point Area' (TPA) method. We have applied it successfully on a number of theoretically simulated TL curves generated in One Trap One Recombination centre (OTOR) model and General-Order Kinetics (GOK) model under quasi-equilibrium approximations with linear heating scheme. The activation energies are found in good agreement with input values for both the models. For OTOR model, temperature average of order of kinetics is estimated to compare with the present result. Systematic analysis is carried out for estimation of errors inherent in the method in the purview of GOK model. A closer look on the results reveals that any set of three points, preferably chosen from the rising side of the curve, can yield activation energy and order of kinetics. The validity of the method to extract $E$ and $b$ from experimental glow curves is exemplified by considering experimental TL data reported in literature. Finally, a complete study starting from the synthesis of a new phosphor $\mathrm{K_2SrP_2O_7:Pr} $ and analysis of the recorded TL data to estimate $E$ and $b$ employing the TPA method has been reported.

Characterization of thermoluminescence kinetic parameters of beta irradiated B doped Ca5(PO4)3OH powder obtained from eggshell

In this study, we have synthesized B doped Ca5(PO4)3OH (HAP) by a sonication chemical method. The thermoluminescence (TL) properties of the family of synthesized samples (B doped Ca5(PO4)3OH (HAP) were investigated using an IRSL-TL 565 nm filter. This gave the highest TL intensity of each phosphor after 2 Gy β-irradiation. Three TL glow peaks of B doped Ca5(PO4)3OH (HAP) are centered at around 84, 208 and 324 °C (with a heating rate of 2 °Cs-1). The trapping parameters such as activation energy (E), order of kinetics (b), frequency factor (s) were calculated by using initial rise (IR), various heating rates (VHR) and computerized glow curve deconvolution (CGCD) method. The response of TL glow curves remained constant within ±5% deviation from the initial value after 9 cycles of reuse; but only at tenth cycle the deviation goes up to 6%.

Neutron detection via thermoluminescence of Tb3+-doped Li2O–Al2O3–B2O3 glasses

We fabricated Tb3+-doped Li2O–Al2O3–B2O3 glasses using 6Li or n Li and 10B or 11B (6Li–10B glass, 6Li–11B glass, nLi–10B glass, and nLi–11B glass) to develop a new thermoluminescent (TL) material for neutron detection and investigated the TL properties of these glasses after X-ray, He ion, and neutron irradiation. TL glow peaks were observed at 350 and 550 K after X-ray irradiation, at 390 and 550 K after He ion irradiation, and at 400 and 600 K after neutron irradiation. The TL intensities around 400 K for 6Li–10B glass, 6Li–11B glass, and n Li–10B glass after neutron irradiation were higher than that of n Li–11B glass, suggesting that the particles generated in 6Li(n, t)4He and 10B(n, α)7Li reactions efficiently induce TL. We observed neutron-induced TL in the range 1 × 107–5 × 108 neutrons cm−2, and the detectable minimum thermal neutron fluence of this glass was estimated to be approximately 4 × 106 neutrons cm−2.

Thermoluminescence of Ce and Nd co-doped CaF2 phosphors after beta irradiation

In this study, we have synthesized CaF2:Nd3+,Ce3+ phosphors by solid state reaction method. The thermoluminescence (TL) properties of the family of synthesized phosphors (CaF2:Ce3+ and CaF2:Ce3+,Nd3+) were investigated using a combination of a SCHOTT BG39 and HC414/46 filters. This gave the highest TL intensity of each phosphor after 10 Gy β-irradiation. Two TL glow peaks of CaF2:Nd3+,Ce3+ phosphor are centered at around 90 and 265 °C (with a heating rate of 2 °Cs−1). The glow peaks displayed a linear dose response in the range of 0.1–50 Gy. Various heating rates (VHR) were performed between 0.5 and 10 °Cs−1. It was seen that the TL intensity at 90 °C decreases and peak maximum temperature shifts to higher temperatures with an increasing heating rate. The TL intensity of the glow peak located at 265 °C increases with heating rate. The initial rise (IR) applied after TM–Tstop experiment and computerized glow curve deconvolution (CGCD) methods in addition to the VHR method on the glow curves of CaF2:Nd3+,Ce3+ phosphor were used to determine the number of peaks, the order of kinetics (b), activation energy (E) and frequency factor (s). The response of TL glow curves remained constant within ±2% deviation from the initial value after 10 cycles of reuse.

Dependence of the thermoluminescent glow-peaks of Mexican zircon of different particle size on the exposure to high gamma radiation doses

The effect of gamma irradiation on the low-pressure phase of ZrSiO4 (zircon) was studied by the thermoluminescence technique and the analysis of the intensity in the TL glow-curves. Specifically, in this approach, the GlowFit computer program was used to solve the complex TL glow-curves produced in zircon after gamma-irradiation. Dose levels of 5, 10, and 30 Mega Gray (MGy) were applied to zircon samples exhibiting particle size of 100, 200, and 300 mesh. The TL results were associated with the main changes in lattice planes observed in the XRD spectra of irradiated samples. Furthermore, the surface damages due to gamma irradiation were evaluated by Scanning Electron Microscopy (SEM) and Atomica Force Microscopy (AFM). The effect of gamma irradiation is verified in the shallow layers of all the zircon samples, but no dependence of the superficial damage was observed regarding the dose of gamma. The size of the zircon particulate was also evaluated as a result of the surface damage in order to elucidate any relationship with the exposure of the material to the radiation.

Neutron-gamma mixed field dosimetry using a 6LiF:Mg,Cu,P thermoluminescent dosimeter

Satisfactory discrimination between the neutron and gamma components in a mixed neutron-gamma field is one of the most important objectives of neutron dosimetry. One of the common techniques for estimating gamma and neutron dose components in mixed neutron-gamma fields is the two peak method. This method has been applied using dosimeters such as LiF:Mg,Ti, but in the present work, a 6LiF:Mg,Cu,P dosimeter has been used, whose thermoluminescence sensitivity is much higher than the LiF:Mg,Ti dosimeter, and therefore, if appropriate results are achieved, it can drastically reduce the dose estimation threshold. Applicability of 6LiF:Mg,Cu,P for estimation of the gamma dose using the two peak method in a mixed thermal neutron-gamma radiation field was studied. The ratio of the area underneath the high temperature thermoluminescence glow peak to dosimetry peak of this phosphor in an Am-Be neutron field is 0.127, while this ratio in a pure gamma ray field of 137Cs is 0.039. The calibration curves were obtained by separately irradiating 6LiF:Mg,Cu,P chips with known gamma and neutron doses. Results show that 6LiF:Mg,Cu,P can be used to estimate the contributions of neutron and gamma doses in a mixed neutron-gamma field by using the two peak method.

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

ABSTRACT We report the detailed analysis of thermoluminescence (TL) glow curves and the evaluation of kinetic parameters of Sm3+-incorporated BaSi2O5.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 β-irradiation consists of two main peaks with maxima at about 91°C and 193°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, 1010 and 1013 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.

Thermoluminescence behavior of gamma irradiated Y2O3:Sm3+ nanophosphor

Thermoluminescence (TL) properties of 60Co gamma irradiated Sm3+ doped Y2O3 nanophosphors were investigated for possible application for high dose gamma radiation dosimetry. Sm3+ doped Y2O3 nanophosphors were synthesized by the solution combustion method. The crystalline phase was analyzed with X-ray diffraction and an average crystallite size was found to be ~20–33 nm. TL glow curves of gamma irradiated Sm3+ doped Y2O3 nanophosphors were recorded. The TL glow curves showed a prominent glow peak at ~400 K, a smaller intensity peak at 510 K and a very weak intensity glow peak at ~640 K. These glow peaks were ascribed to host defects and Sm3+ characteristic emission. The effect of Sm3+ concentration on the TL was explored and the optimum Sm3+ concentration was found to be 0.1 mol%. The number of overlapping TL glow peaks were identified from the broad TL glow curve by the thermal cleaning method. The kinetic parameters were obtained by the glow curve deconvolutions method using the general order kinetics expression. The variation of the TL intensity with dose, the effect of heating rates, repeatability and the fading effects of gamma irradiated Sm3+ doped Y2O3 nanophosphors were also studied. TL emission showed a strong green (545 nm) emission at ~400 K and a characteristic Sm3+ emission was observed at a high dopant concentration. The results obtained were favorable for the application of high dose gamma radiation dosimetry.

UNCERTAINTY OF THERMOLUMINESCENCE AT LOW DOSE LEVELS: A MONTE-CARLO SIMULATION STUDY.

The purpose of the current work is to investigate the effect of the scatter data and the background noise level on the uncertainty of the thermoluminescence (TL) measurements. The Monte-Carlo (MC) algorithm has been used to simulate the scattering data and the background noise signal in TL glow-curve. Under the simulation and experimental parameters used in the present study, a new general criterion for the minimum measurable dose has been established. It has been found from the results that the TL measurements, using either the peak maximum or the peak integral, can be conducted with an uncertainty level $<\pm 10\%[2\sigma ]$ when the TL signal is at least 10 times greater than the background noise signal. It has also been found that the same criterion can be used for the evaluation of the kinetics parameters of the TL glow-peak using either the peak fitting or the peak shape methods.

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.

Thermoluminescence glow curve analysis and kinetic parameters of Dy-doped BaSi2O5 phosphor

In this paper, Dy3+ incorporated BaSi2O5 phosphors were synthesized by gel combustion method and characterized by X-ray diffraction (XRD). The effects of various heating rates on thermoluminescence (TL) kinetics and glow peak temperatures of Dy3+ incorporated BaSi2O5 phosphors exposed to β irradiation at room temperature were investigated. The glow curves of the phosphor exposed to β-irradiation (0.1–100 Gy) consist of four main peaks located at 87, 130, 271, and 327 °C and exhibit a good linearity between 0.1 and 100 Gy. Three experimental techniques including variable heating rate (VHR), repeated initial rise (RIR), peak shape (PS) and computerized glow curve deconvolution (CGCD) were employed to determine TL kinetic parameters. Our findings indicate that the TL glow peaks of the phosphor obey first-order kinetics. Analysis of the main dosimetric peaks through the techniques mentioned above indicates that activation energies (E) and pre-exponential factor (s) are in the range of 0.80–1.50 eV and 1.15 × 108–3.28 × 1013 s−1. Additionally, 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 effect on the TL intensities and glow peak temperatures of the heating rate is discussed in terms of thermal quenching.

The impact of γ-irradiation on Cd-B2o3 glass doped WO3: New evidences by TL and ESR spectroscopy

A well resolved Thermoluminescence (TL) glow peak at ~168 °C was observed in Cd-borate glass doped WO3. The maximum TL intensity was observed for 1.5 mol% of WO3+ doped samples and thereafter decreases. The variation of gamma exposure (0.025→2 kGy) on TL glow curves of Cd-borate glass showed linear and sub-linear behavior supported by track interaction model (TIM). Here γ-irradiated sample shows the formation of shallow trap (surface trapping) beside the formation of deep trapping. The composition dependence of the g ≈ 1.94 ESR absorption line intensity shows a decrease with increasing WO3 content, which is attributed to a fall in the ratio of the number of unpaired pentavalent ions W5+ ions to the number of W6+ ions. The effect of gamma irradiation doses on TL and ESR studies show high response with dose which indicates that these glass samples may be useful for TL dosimetry.