Luminescence studies on rγ-ray-irradiated Dy 3+ -activated sodium chloride phosphor for radiation dosimetry (original) (raw)
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KCl:Dy phosphor for thermoluminescence dosimetry of ionizing radiation
Luminescence, 2013
The thermoluminescence (TL) characterizations of g-irradiated KCl:Dy phosphor for radiation dosimetry are reported. All phosphors were synthesized via a wet chemical route. Minimum fading of TL intensity is recorded in the prepared material. TL in samples containing different concentrations of Dy impurity was studied at different g-irradiation doses. Peak TL intensities varied sublinearly with g-ray dose in all samples, but were linear between 0.08 to 0.75 kGy for the KCl:Dy (0.1 mol%) sample. This material may be useful for dosimetry within this range of g-ray dose. TL peak height was found to be dependant on the concentration (0.05-0.5 mol%) of added Dy in the host.
Lyoluminescence (LL) of microcrystalline K 3 Na(SO 4) 2 :Eu 3 þ was studied for different doses and for different pH values of solvents. The material was prepared by a simple melt method and was then crushed and sieved to get particle sizes in different ranges between 50-250 mm. K 3 Na(SO 4) 2 :Eu 3 þ (0.1%) phosphor thus obtained was given proper heat treatment (annealed at 800°C for 1 h). It was then irradiated with γ rays from 60 Co radioactive source to study its LL characteristics and the effect of pH of the solvent on LL intensity. The glow (decay) curves, dose response and variation of the LL intensity with pH were studied for different doses (10 Gy-25 kGy). pH of the solutions used for studying LL was varied in the range of 0.55-13.0 using different diluted acids (i.e., H 2 SO 4 , HCl and HNO 3) and alkalies (i.e., LiOH, NaOH and KOH) solutions. The LL intensity was not only found to vary with the net pH of the solution used for taking LL but also with the different acids/alkalies used for varying the pH. This has a great importance in radiation dosimetry using LL as the user needs to know which solution is best suited. The material shows linear dose response for a broad range of doses (10 Gy-10 kGy). It was also observed that the fading of the LL intensity is more if the material is exposed to room light than its storage in dark. Very wide dose range, high-sensitivity and low fading make the material suitable for dosimetry of high-energy radiations using LL technique.
Journal of Luminescence
Lyoluminescence (LL) of microcrystalline K 3 Na(SO 4) 2 :Eu 3 þ was studied for different doses and for different pH values of solvents. The material was prepared by a simple melt method and was then crushed and sieved to get particle sizes in different ranges between 50-250 mm. K 3 Na(SO 4) 2 :Eu 3 þ (0.1%) phosphor thus obtained was given proper heat treatment (annealed at 800°C for 1 h). It was then irradiated with γ rays from 60 Co radioactive source to study its LL characteristics and the effect of pH of the solvent on LL intensity. The glow (decay) curves, dose response and variation of the LL intensity with pH were studied for different doses (10 Gy-25 kGy). pH of the solutions used for studying LL was varied in the range of 0.55-13.0 using different diluted acids (i.e., H 2 SO 4 , HCl and HNO 3) and alkalies (i.e., LiOH, NaOH and KOH) solutions. The LL intensity was not only found to vary with the net pH of the solution used for taking LL but also with the different acids/alkalies used for varying the pH. This has a great importance in radiation dosimetry using LL as the user needs to know which solution is best suited. The material shows linear dose response for a broad range of doses (10 Gy-10 kGy). It was also observed that the fading of the LL intensity is more if the material is exposed to room light than its storage in dark. Very wide dose range, high-sensitivity and low fading make the material suitable for dosimetry of high-energy radiations using LL technique.
The International Conference on Mathematics and Engineering Physics, 2006
For routine dosimetry, several TLD materials have been used, each having its own definite properties. In this paper, the physical TL properties of the three used commercial thermoluminescent (TL) materials, [ LiF (TLD-100), CaF 2 :Dy (TLD-200) and CaSO 4 :Dy (TLD-900) ], have been studied in order to identify the efficiency of the optimum material for gamma radiation measurements. The main investigated dosimetric properties are glow curve structure, sensitivity, dose response, fading, memory effects and sensitization. The experimental results show that the glow curve structure of the , TLD-100 includes 4 glow peaks at 135, 182, 210 & 230 o C , TLD-200 includes 2 peaks at 179 & 240 o C and TLD-900 includes 3 peaks at 123, 220 & 338 o C. The sensitivity of TLD-200 was found to be 9-20 times greater than the standard one (TLD-100), but for TLD-900, it was found 8-13 times greater than the standard one. It was found that the TL response of the three phosphors fit to a straight line in the logarithmic scale from, 50 µGy-5 Gy , 50 µGy-10 Gy and 5 µGy-10 Gy, respectively. The fading values were found to be ≈ 7.5 & 20.1 %, 14 & 32% and 10.4 & 12 % for the three phosphors, respectively, after the storage for 3 months at 25 & 50 o C, respectively. From the results which previously mentioned, calcium Sulphate doped by dysprosium has been selected for local preparation.
Glow curve analysis ofβ-particles irradiated Na21Mg(SO4)10Cl3:Dy phosphor
Dy doped Na 21 Mg(SO 4 ) 10 Cl 3 phosphor was prepared by modifying the solid state method and the formation of the compound was confirmed by X-ray diffraction (XRD) study. Morphology of the phosphor was analyzed by scanning electron microscopy (SEM). The thermally stimulated luminescence (TSL) studies of Dy doped Na 21 Mg(SO 4 ) 10 Cl 3 samples show the complex glow curve. Powder samples of Na 21 Mg (SO 4 ) 10 Cl 3 :Dy were irradiated by 2.2 MeV β-particles within dose range of 100-16,000 mGy. Analysis of the thermoluminescence glow curves was carried out by T m -T stop and glow curve deconvolution (GCD) method. Trapping parameters (activation energy and frequency factor) for individual deconvoluted peaks were obtained by Chen's peak shape method. The comparison of trapping parameters between γ-ray irradiated and β-particles irradiated Na 21 Mg(SO 4 ) 10 Cl 3 :Dy phosphor were also studied.
A review: Thermoluminescence dosimeteric application for phosphor
AIP Conference Proceedings, 2019
Thermoluminescence (TL) dosimetry has emerged as an important technique for understanding the dynamics of electron trapping centers. TL glow-curve analysis methods have been applied to study the kinetics of trapped electrons and the activation energy of the corresponding\ electrons. Such methods include Chen's Peak shape method, Initial Rise and Variable Heating Rate method. Although, the TL does prove the presence and the depth of electron trapping centres and it does not give direct information about the shallow electron trapping centres, Thermoluminescence dosimeters (TLD) are one of the most highly efficient means of characterization over a wide range of radiation doses. New materials are being introduced which allow more sensitivity and linearity in the radiation response of the TL signal output. Phosphors shows TL emission when it gets exposed to high ionizing radiation such as γ-rays, β-rays,C 5+ (carbon-ion) beam etc. Energy gets stored in the material and this stored energy is emitted in the form of light when the material is heated. This phenomenon is used for measuring radiation dose. TL property of inorganic materials are decided by the factors such as crystal structure, band gap, synthesis process, crystal size, lattice imperfections and effects of impurities on solid. Lattice imperfections are described as defect centers that may occur when ions of either sign ions move away from their original sites thus leaving vacant sites that are able to interact with free charge carriers.
Indian Journal of Physics, 2012
The mechanoluminescence (ML) of c-irradiated coloured powder of NaBr:Ce(0.1-10 mol%) phosphor are reported in this paper and compared with pure NaBr material. All samples were prepared by wet-chemical method. Single isolated ML glow curve is observed in all samples. The variation of peak ML intensity with gamma exposure and with different concentration of Ce 3? doped, in NaBr:Ce are studied. ML intensities are found to be dependant on concentrations of Ce 3? and gamma radiation dose. The variation of peak ML intensity of NaBr:Ce(0.5 mol%) with different gamma dose is found as sublinear up to 2.5 kGy high dose of c-irradiation.
Journal of Luminescence, 2019
Potassium calcium borate doped with dysprosium was synthesized by solid state diffusion method. Phase determination and compound confirmation were done by x-ray diffraction (XRD). Crystallite size calculated using Scherrer's formula was found to be around 117 nm. Other characteristics were studied using techniques like field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR). Band gap of the material was determined using ultraviolet-visible diffuse reflectance spectroscopy (UV-VIS DRS). The phosphor KCaBO 3 :Dy was irradiated by photon beams (of 1.25 MeV gamma and 4.88 eV UV rays) and ion beams (of 65 MeV and 85 MeV of O 6+ and 75 MeV of C 6+) with different doses in order to study its thermoluminescence (TL) properties. The phosphor showed good TL sensitivity towards these ionizing radiations. A good linear dose response was also shown by the phosphor for photon beam exposure. However, in case of ion beams exposure, dose response of the phosphor was good only for low energy oxygen ion beam. Also the phosphor showed good photoluminescence (PL) property with sharp peaks present in the PL emission and excitation spectra corresponding to the characteristic peaks of the dopant Dy. The Commission International de l'E clairage (CIE) was also used to calculate chromaticity coordinates and color temperature in order to investigate the phosphor's application in white LEDs. All these good characteristics make this phosphor a suitable candidate for radiation dosimetry and solid state lighting.