Thermoluminescence Properties Research Articles

Investigation on structural and thermoluminescence properties of Ho3+doped SrB4O7 phosphor for dosimetry applications

A series of tissue equivalent novel Sr(1-x)B4O7:Hox (0 ≤ x ≤ 0.5 mol%) phosphors have been synthesized via solid state diffusion to investigate their structural and Thermoluminescence features. The rietveld refinement of XRD data confirms pure phase formation with an orthorhombic crystal structure. FTIR and Raman spectroscopy have been used to examine the vibration characteristics and bonding among each constituent of material. The analysis detected bending vibrations of bridging oxygen's within B-O-B bonds in BO3 trigonals, alongwith stretching vibrations of [BO4] tetrahedral. SEM was used to inquire the surface morphology as well as to record EDX patterns for authentication of the elemental composition in all the samples. The microphosphors possess a dense structure with irregularly shaped grains with an average grain size of 1.36–1.45 µm. The TL glow curves have been recorded to evaluate the dosimetric properties of γ-exposed phosphors i.e. dose response, fading and reproducibility. Doped samples exhibit higher TL sensitivity as compared to pure samples. The critical holmium concentration for TL was found to be 0.5 mol%. Fading was examined and the TL intensity of the predominant dosimetric TL Peak of SB3 sample was determined to be a -12% decline after 15 days. Repetitive analysis demonstrates that SrB4O7 have high reproducibility. The phosphors exhibit a linear dose response and good reproducibility, with a standard deviation of ∼2%. The trapping parameters (viz. E, b and s) have been computed using PS, IR and Ilich methods. The dosimetric attributes of the novel fabricated phosphors acknowledge their adequacy for dosimetry applications.

Synthesis, Thermoluminescence and Photoluminescence Study of Gd3+ Doped La2Zr2O7 Phosphor

Thermoluminescence (TL) and photoluminescence (PL) properties of the Gd3+ doped lanthanum zirconium phosphor (La2Zr2O7:Gd3+) are reported in this work. Gd3+ doped La2Zr2O7 (LZO) phosphor has been prepared via a high temperature solid state reaction method and it was prepared by using H3BO3 (as flux) and the preliminary materials were La2O3, ZrO2 and Gd2O3. The results of the XRD study shows that La2Zr2O7:Gd3+ phosphor has the cubic structure with 51.68 nm average crystallite size. The TL studies were carried out for the prepared phosphors using UV radiation (UV 254 nm), and a single glow peak was found in this study. Herein to extract the information about the positions of the TL emission at this work the peak shape methods are usage and the maximum peak exhibit the general order kinetics. In TL study the effect of UV exposure was investigated, it was found that it showed linearity with dose, which is helpful in TL dosimeters. The PL emission peaks of Gd -doped LZO phosphors were found to be in the region 450-650 nm, which was due to the 4f-4f transitions of Gd3+. More intense peaks at 468, 539, 589 and 627 nm were found at room temperature under excitation at 276 nm. Here the afterglow and photoluminescence behaviour of the Gd doped LZO phosphor is also reported.

Synthesis of potassium chloride crystals doped with dysprosium and ‎investigation of its thermoluminescence and photoluminescence properties ‎

In this study, the thermoluminescece (TL) behavior of potassium chloride dosimeter doped with dysprosium impurity (KCl:Dy) was studied. Evaluation of the morphology, shape and size of prepared crystal were done by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. Potassium chloride was prepared by co-precipitation with different percentages of dysprosium impurities and the best TL response was determined for gamma rays in 0.5 mol% of impurity. The optimum annealing regime was obtained at 700 for 30 minutes. Using a general order kinetic based on computer simulator, the glow curve and corresponding kinetics parameters were calculated. The TL glow curve of synthesized dosimeter shows two peaks at 393 and 415 K. Also, other dosimetric properties such as fading and TL dose response were studied

Neutron-induced thermoluminescence properties of Tb3+-doped Ca2B2O5 ceramics

We fabricated 10B-enriched (10B ceramics) and 11B-enriched (11B ceramics) Ca2B2O5:Tb ceramics as thermoluminescence (TL) materials for neutron detection applications. The TL properties of the ceramics after X-ray irradiation, particle beam irradiation, and neutron irradiation were investigated. The TL properties of the 10B ceramics and 11B ceramics after X-ray irradiation were similar, whereas the neutron-induced TL intensity of the 10B ceramics was significantly higher than that of the 11B ceramics. The different TL properties of these ceramics are due to the α-rays, Li ions, and γ-rays generated during the 10B(n, α)7Li reaction. The lower limit of neutron detection by the ceramics was less than 2 × 107 neutrons cm−2, which was lower than those of several previously reported TL materials. Therefore, these ceramics can be applied as TL dosimetry materials for neutron detection.

Characterization of thermoluminescence kinetic parameters of dolomite after exposure to β-radiation dose

Dolomite is a carbonate mineral of calcium and magnesium having the chemical formula CaMg(CO3)2. It is a reservoir for significant petroleum reserves and mainly used as building and ceramic material. Thermoluminescence (TL) emission of this mineral has been examined in the literature, especially collected from Egypt, India, and Brazil. In this study, the aim is to investigate TL properties of dolomite mineral which has a wide reserve in Mersin/Turkey. Structural, morphological, and elemental analyzes were performed by X-ray Diffraction (XRD) Spectroscopy, Scanning Electron Microscope equipped with Energy Dispersive X-ray Spectrometer (SEM-EDS), and Inductively Coupled Plasma Mass Spectrometer (ICP/MS), respectively. TL measurements were carried out using a TL/OSL reader with a90Sr/90Y beta source. The natural TL (NTL) curve of the sample showed two peaks at around 255 and 345 °C by the wideband blue filter whereas an additional peak at 115 °C was observed under the beta irradiation. In addition, at high doses from 50 Gy, a shoulder at around 402 °C occurred. The optimum annealing temperature and duration of the sample were determined as 500 °C and 30 min. In order to remove the low-temperature peak, a preheating process at 200 °C with 23 s duration was applied before each TL readout. TL response to absorbed dose showed good linearity over the 0.1–1200 Gy dose range and the sample was observed to be reusable with only 1.7% change up to 10 cycles under a dose of 100 Gy. The kinetic parameters (activation energy E (eV), frequency factor s (s−1), kinetic order b) of the evident glow peaks were estimated using Peak Shape (PS), Various Heating Rate (VHR), Initial Rise (IR), and Computerized Glow Curve Deconvolution (CGCD) methods. The kinetic analysis indicated that the TL glow curve of the preheated sample consists of four individual peaks having activation energies of ∼1.56, 1.60, 1.78, and 1.73 eV, and these peaks obey second and general-order kinetics.

INVESTIGATION OF THE TL CHARACTERISTICS OF COMPOSITE PEAK 5 IN THE GLOW CURVE OF LIF:MG,TI (TLD-100) USING NATURALLY AND FURNACE-COOLED SAMPLES FOLLOWING THE 400°C PRE-IRRADIATION ANNEAL.

The cooling rate to room temperature following the 400°C pre-irradiation anneal is known to affect the thermoluminescent properties of LiF:Mg,Ti (TLD-100) as a result of migration and clustering of defects during the cooling down process. In this investigation the dose response over an extended dose range from 0.01 to 7000Gy in both naturally cooled and the much slower furnace-cooled samples has been measured. Glow curve deconvolution based on first-order kinetics is employed to extract the dose response of the various glow peaks. Of especial interest is the behaviour of glow peaks 4, 5a and 5 as a function of dose. The idea is to modify the supralinear dose response of peak 5 from 1 to 30Gy to a linear behaviour. This dose range is important for clinical therapy and a linear dose response is of substantial advantage leading to both improved accuracy and precision.

Design of green emitting CaZrO3:Tb3+ nanophosphor: Luminescence based platform for real-time ultrasensitive detection of latent fingerprints and anti-counterfeiting applications

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.

Thermoluminescence properties and evaluation of trapping parameters of Eu3+ and Dy3+ activated K3Ca2(SO4)3Cl phosphors

ABSTRACT In this study, we have reported thermoluminescence (TL) properties and trapping parameters of Eu3+ and Dy3+ -doped K3Ca2(SO4)3Cl phosphors. The host materials have been prepared by a simple cost-effective wet chemical method. The TL glow curves of γ-irradiated halo-sulfate phosphors are observed at a constant heating rate of 5°C/s and a dose rate of 0.3712 kGy/hr for 3Gy dose. The TL glow curve of synthesized phosphor samples has a simple glow curve with an isolated peak. K3Ca2(SO4)3Cl:Eu3+ phosphors show TL response linearity in the range of 12Gy–62Gy. But, K3Ca2(SO4)3Cl:Dy3+ phosphors show TL response linearity in the range of 12Gy–87Gy. In this work, we have also calculated the trapping parameters of synthesized phosphors by different methods, such as Chen’s peak shape method, Initial Rise (IR) Method, Ilich method, E-Shape glow curve method, E-Luschik methods, E-Halperin and Braner method. An easy method of synthesis, simple glow curve with isolated peak, efficient dose response, low value of activator concentration and low fading suggests that these phosphors may be potential candidates for thermoluminescence dosimetry and image storage.

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.

Thermoluminescence dosimetry properties of Tm3+ doped fluoroelpasolite Cs2NaYF6 crystals synthesized under hydrothermal conditions

Detailed research of thermoluminescence (TL) properties of Tm3+ doped fluoroelpasolite Cs2NaYF6 crystals synthesized under hydrothermal conditions has been carried out in order to develop new dosimetric material. The basic dosimetric properties of Cs2NaY0.99Tm0.01F6 crystals (Zeff = 33) exposed to beta radiation, such as a TL glow curve shape, beta-dose response, reproducibility, dark fading, have been investigated by using ordinary TL technique at a typical heating rate of 2 °C/s. At this heating rate the Cs2NaY0.99Tm0.01F6 crystal exhibits three well-separated TL peaks: a rapidly decaying peak at 100 °C (Peak 1), a stable peak at 171 °C (Peak 2), and one more low-intensity peak at 240 °C (Peak 3). The deviation of reproducibility for 10 repeated readings of individual samples after exposure to 5 Gy of beta irradiation is <1%. The TL output as a function of beta irradiation dose exhibits linear dose-response up to 1 kGy. The anomalous fading of the TL signal has been observed for the Cs2NaY0.99Tm0.01F6 crystals. The short time fading characteristics have been studied for different periods of up to one week. Using the various heating rates (VHR), Chen's peak shape, and computerized glow curve deconvolution (CGCD) methods, the kinetic parameters have been calculated specifically for the Peak 2 of the TL glow curve. Spectra of X-ray excited radioluminescence (RL) have been studied in the range of 200–1000 nm. The results of this study show that the simple TL glow curve structure, relatively high sensitivity to ionizing radiation, the wide range of measurable doses from 0.2 Gy up to 1 kGy, and reusability make this novel Cs2NaY0.99Tm0.01F6 dosimetric material a promising candidate for its applications in radiation dosimetry in particular for measurement of high radiation doses.

Understanding the role of fuels and impure phases on photoluminescence and thermoluminescence properties of combustion-derived nano Sr2 CeO4 blue light-emitting phosphor.

Despite great advancements in optical materials and luminescent hosts, self-luminescent blue-emitting phosphors are very limited. In this study we present the influence of fuels used in combustion synthesis on the photoluminescence and thermoluminescence (TL) characteristics of self-luminescent Sr2 CeO4 blue-emitting phosphors. Four different fuels, oxalyldihydrazide (ODH), sugar, glycine, and ethylenediaminetetraacetic acid, were used to synthesize Sr2 CeO4. Powder X-ray diffraction patterns showed that pure orthorhombic Sr2 CeO4 was formed only with the ODH fuel and the other fuels resulted in the formation of impurity phases. Excitation spectra showed peaks at ~290 and 340 nm, corresponding to charge transfer bands from different O2 - to Ce4+ ions. The emission spectra showed an intense blue-emitting band at 470 nm and the highest emission intensity was found for the sample prepared with ODH. Furthermore, TL glow curves for the γ-irradiated Sr2 CeO4 nanophosphor showed that ODH as fuel produced a more intense glow curve compared with other fuels investigated. TL glow curve analysis was carried out by calculating parameters such as activation energy, frequency factor, and order of kinetics. This study explores the importance and role of fuel in tuning the optical properties of phosphor hosts.

Characterizing and comparing the kinetic parameters of Gd3+ doped hafnium oxide nanoparticles in clinical photon and neutron beam

Thermoluminescence (TL) properties of Gd3+(0,1,3,5 &7 mol%): HfO2 NPs were synthesized by precipitation and co-precipitation method. The synthesized materials were irradiated in gamma, 6 MV, 10 MV, 15 MV and Am–Be neutron source. The glow curve were deconvoluted and analyzed by curve fitting with good values of FOM. The kinetic parameters such as order of kinetics (b), activation energy (Ea) and frequency factor (s) were determined by chen's peak shape method. The result shows that the intrinsic HfO2 has higher number of traps compared to extrinsic HfO2 due to the enrichment of oxygen vacancies. The TL glow curve achieved the higher TL counts in Gd (5 mol%) and above these concentration TL counts decreases due to concentration quenching. High energy beams such as 10 MV and 15 MV also shows similar result and verified with photon dose-linearity for the dose range in 5 cGy–100 cGy. Finally, the study concludes that the effect of doping material such as Gd3+ has the influence of their relative concentration in the host material to provide the information about pure HfO2 NPs suitable for gamma rays and X-rays(6 MV) and for neutron detection Gd(5 mol%) doped HfO2 can be used.

Use of Terbium Doped Phosphate Glasses for High Dose Radiation Dosimetry—Thermoluminescence Characteristics, Dose Response and Optimization of Readout Method

The phosphate glass samples doped with Tb2O3 oxide (general formula: P2O5-Al2O3-Na2O-Tb2O3) were synthesized and studied for usage in high-dose radiation dosimetry (for example, in high-activity nuclear waste disposals). The influence of terbium concentration on thermoluminescent (TL) signals was analyzed. TL properties of glasses were investigated using various experimental techniques such as direct measurements of TL response vs. radiation dose, Tmax–Tstop and VHR (various heating rate) methods, and glow curve deconvolution analysis. The thermoluminescence dosimetry (TLD) technique was used as the main investigation tool to study detectors’ dose responses. It has been proved that increasing the concentration of terbium oxide in glass matrices significantly increases the thermoluminescence yield of examined material. For the highest dose range (up to 35 kGy), the dependence of the integrated thermoluminescent signals vs. dose can be considered as a saturation-type curve. Additional preheating of samples improves linearity of signal vs. dose dependencies and leads to a decrease of the signal loss over time. All obtained data suggest that investigated material can be used in high-dose radiation dosimetry. Additional advantages of the investigated dosimetric system are its potential ability to re-use the same dosimeters multiple times and the fact that reading dosimeters only requires usage of a basic TL reader without any modifications.

Synthesis and evaluation of thermoluminescence properties of ZrO2:Mg for radiotherapy dosimetry.

This study aimed to investigate the thermoluminescent properties of ZrO2:Mg irradiated with a 6MV X-ray beam and its potential application in radiotherapy dosimetry. ZrO2 powder was synthesized using the sol-gel method and Mg was used as a dopant. Irradiations were performed with ZrO2:Mg chips located at the center of a 10 × 10cm2 radiation field at a source surface distance of 100cm, below a stack of solid water slabs, at the depth of maximum absorbed dose. The investigated characteristics of the material included linearity with radiation dose, reproducibility, accuracy, sensitivity and fading. Regarding the intrinsic difference of the samples, the glow curves of the investigated ZrO2:Mg chips exposed to 1Gy of 6 MV X-rays exhibited three or four peaks. The ZrO2:Mg samples showed a 47% fading at 24h after irradiation, and the reproducibility of the thermoluminescence reading of ZrO2:Mg for equal irradiation conditions was ± 21%. The thermoluminescence response of the investigated ZrO2:Mg samples to various absorbed doses from 0.5 to 2.5Gy showed a gentle increase of the thermoluminescence intensity with increasing absorbed dose. The obtained results show that ZrO2:Mg is not an appropriate candidate for X-ray photons in radiotherapy, due to low thermoluminescence peak temperature, low reproducibility, low sensitivity to various absorbed doses and significant fading.

Judd-Ofelt analysis and luminescent characterization of Eu3+ activated Li2Zr(PO4)2 phosphor

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.

Classification of thermoluminescence features of CaCO3 with long short-term memory model.

Calcium carbonate (CaCO3 ), a mineral commonly found in the Earth's crust, is mainly in the forms of calcite and aragonite. Calcite has the most stable type of thermodynamics at room temperature and ambient pressure. It has wide band gap structure and is of great interest for a wide-range technical and industrial applications due to its physical properties and suitability. In this study, a new method based on the long short-term memory (LSTM) model of deep learning is proposed to classify the thermoluminescence properties such as fading, cycle of measurement, heating rate, and dose-response of CaCO3 . Therefore the thermoluminescence properties of calcite was investigated as a suitable band structure and its coherent data were used to classify the features using a deep learning LSTM model. Experiments were carried out on a dataset consisting of four classes. The accuracy, precision, and sensitivity values of the proposed model obtained were 98.34, 97.90, and 98.56%, respectively. The classification process of the results obtained from the designed model showed good performance.

Tailoring of thermoluminescent properties and assessment of trapping parameters of natural fluorite samples from Dogargaon fluorite mines, India.

Mineral fluorite or fluorspar (CaF2 ) can host significant quantities of trivalent REE3+ (rare earth element) by substitution with divalent Ca2+ . The fluorites associated with carbonatites are often REE-rich compared to those derived from sedimentary, hydrothermal, or Mississippi Valley-type (MVT) fluorites. The naturally occurring fluorites have several industrial applications one of which is for luminescence. Whether or not REE enriched, the fluorite makes an ideal host for REEs, which are very important phosphors. The naturally occurring fluorites are available in sufficient quantities to cater to the industrial demand. Investigations have been carried out on the fluorites from active fluorite mines at Dongargaon in central India. Thermoluminescence behavior of a natural fluorite sample was investigated using a Nucleonix TL 1009I thermoluminescence reader. Multiple traps formed in the broad thermoluminescent (TL) glow curve were found by TL anal deconvolution software. Trapping parameters for all multiple traps formed on deconvoluting broad TL glow curve were found by different methods like Initial rise method, Chen's Peak shape method and Ilich method.

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 properties of natural Egyptian calcite

The current study was going to investigate the thermoluminescence properties for calcite veins associated with the Banded Iron Formation in Wadi Kariem, Egypt. The crystalinity of the calcite samples examined by XRD technique. The samples were irradiated by ɣ-source to different doses from 250 mGy up to 2 KGy. The kinetic analyses for the thermoluminescence glow curves were deconvoluted by new designed TL software. It was observed that there were composed of 6 overlapped trapping and their activation energies were determined by glow curve deconvolution (CGCD) and Peak shape (PS) methods. The results of the two methods exhibited a good agreement with each others. The samples exhibited also a low sensitivity of 4.33 less than that of LiF for gamma radiation and the minimum detectable dose was detected to be 186 μGy. The samples displayed a gamma linear dose response from 5 Gy up to 2 kGy. The current study recommended to start the measurements of the calcite samples after 2 days to give established measurements.