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A trivalent Dy3+‐activated K3Ca2(SO4)3F 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 K3Ca2(SO4)3F:Dy3+ phosphor was irradiated using γ‐rays from a 60Co 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 1 mol% of Dy3+ ion with a single TL glow peak. The TL glow curve revealed linearity with increase in exposure dose range from 0.1 kGy to 3.0 kGy. 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 K3Ca2(SO4)3 phosphor revealed excellent TL properties and was found to be a potential candidate for dosimetric applications. [ABSTRACT FROM AUTHOR]

The series of Mn2+ single doped fluoride-based K3Ca2(SO4)3F phosphor was prepared by the conventional high temperature solid-state reaction method. The formation of phase purity and morphology was studied by the XRD and SEM analyses. The prepared material was irradiated by γ-rays from 60Co source and the thermoluminescence (TL) characteristic was carried out by Nucleonix 1009I TL reader. The prominent TL dosimetry peak observed for K3Ca2(SO4)3F:1mol% Mn2+, annealed at 800°C centred at 217°C, revealed deeper traps. The TL exhibits a linear response as a function of dose rate up to 4 kGy. The computerised glow curve deconvolution (GCD) method, employed for the analysis of TL glow curve, shows the kinetics of the first order. The trapping parameters were evaluated using Chen's peak shape method, initial rise method and Ilich method. The results exhibit that the synthesised phosphor was found to be a potential candidate for radiation dosimetry applications. [ABSTRACT FROM AUTHOR]

Rare earth ion plays an important role in the solid state lighting industry. Here, the terbium (III) ion doped sodium calcium chlorosulfate phosphor was prepared via wet chemical method. Structure, bonding between each element of the sample and morphology of the sample were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM), which showed that the samples were crystallized in a well known structure. XRD study shows the crystalline nature of the phosphor materials prepared at low temperature. Photoluminescence study of prepared phosphor was done using SHIMADZU Spectrofluorophotometer RF-5301 PC with a xenon lamp as the excitation source. The excitation spectra are obtained between 280 and 430 nm ranges on doping of terbium (III) ion. Among all these transitions excitation at 380 nm is strong excitation owing to 7F6 → 5G6 transition. The emissions from terbium (III) ions are at 416, 437, 490 and 545, 586, 621 nm. These emissions are attributed to 5D3→7F5 (417 nm), 5D3→7F4 (437 nm), 5D4→7F6 (491 nm) and 5D4→7F5 (545 nm), 5D4→7F4 (588 nm), 5D4 → 7F3 (624 nm) transitions of terbium (III) ions. Among these strong emission peak appears in green region at 545 nm. [ABSTRACT FROM AUTHOR]

Fluorapatite Ca9La(PO4)5(SiO4)F2: Eu with variable molar concentrations of Eu3+ (0.05–1.0 mol%) were synthesised by the solid-state reaction method and their photoluminescence (PL), thermoluminescence (TL) characteristics were studied after irradiating the samples with γ-rays and 75 MeV O6+ ion beam. The formation of the material was confirmed using X-ray diffraction pattern followed by Scanning electron microscopy and Fourier transform infra-red (FTIR) spectrum. The morphology of the synthesised powder was observed to be polycrystalline constituted by microcrystalline particles. FTIR spectrum shows characteristic bands, 563 cm−1 for bending vibration υ4 and 1035 cm−1 for stretching vibration υ3. PL spectra show absorption bands at 395 and 466 nm corresponding to 7F0→5L6 and 7F0→5D2 transitions and the emission band was seen at around 595 and 616 nm describing 5D0→7Fj transitions (j = 1,2). Furthermore, TL glow curves of both γ-rays and 75 MeV O6+ ion beam irradiated samples show a prominent peak at around 145°C with a small hump at around 245°C. The concentration 0.2 and 1 mol% was found to be the best concentration for studying TL properties of Ca9La(PO4)5(SiO4)F2: Eu irradiated with γ-rays and 75 MeV O6+ ion-beam respectively. [ABSTRACT FROM AUTHOR]

The present phosphor K2Ca(SO4)2, doped by dysprosium and europium, is synthesized by the solid-state diffusion method. The doping concentration varied from 0.1 to 0.5 mol% by weight. A phosphor is studied for X-ray powder diffraction, surface morphology analytical scanning electron microscopy and analyzed by energy-dispersive X-ray spectroscopy. The prepared phosphor K2Ca(SO4)2, doped by Dy and Eu, has been characterized for thermoluminescence (TL) glow curve, showing maximum peak temperatures at 176°C and at 200°C, respectively. TL peak intensity of K2Ca(SO4)2: Dy and Eu was compared with the standard TLD CaSO4:Dy phosphor. Both phosphors show the dose linearity ranging from 20 to 240 Gy doses of γ-rays of 60Co source at room temperature. Negligible fading has been observed when irradiated with γ-rays and stored for 60 days without taking any care from sunlight. The TL materials were used in powder forms. The linearity of ESR response with dose for powder forms of K2Ca(SO4)2: Dy was also studied using the signals at g = 2:0039 (SO3−) and at g = 2:02282 (SO4−). It was observed that the range of linearity of dose response extended between 20 and 240 Gy. Kinetic parameters have been calculated using three different methods: Chen's peak shape method, various heating rate method and initial rise method. To study the heating rate method, the glow curve was recorded for the heating rate as 1°C, 3°C, 5°C, 7°C, 9°C each time. Electron spin resonance (ESR) shows the ionic radical formation during γ-irradiation, which is responsible for TL. The effect of temperature and microwave power on the ESR signal was also studied. [ABSTRACT FROM AUTHOR]

Sr2B5O9Cl: Dy phosphor was synthesized by modified solid state diffusion method and the impact of C5+ ion-beam on its TL behavior was studied in detail. Phosphor was annealed at 1000 °C for obtaining single phase host. XRD technique was used to confirm the formation of the material and was matched with JCPDS-27-08835. The synthesized phosphor was characterized for photoluminescent spectra. Characteristic emission at 484 nm (4F9/2→6H15/2) and 575 nm (4F9/2→6H13/2) confirms the presence of Dy3+ ions in the Sr2B5O9Cl host matrix. Further TL properties of the synthesized material were studied for fluence range 1.5 × 1011-30 × 1011 ion/cm2 (i.e. 40.14-802.9 kGy dose) of C5+ ion-beam (75 MeV) and were found to show the non linear behavior between a dose range 40.14-802.9 kGy. TL glow curve for Sr2B5O9Cl:Dy irradiated with C5+ ion-beam (75 MeV) was compared with that of γ-ray irradiated phosphor. TRIM/SRIM calculations were performed to correlate the changes in TL properties of Sr2B5O9Cl:Dy phosphor. [ABSTRACT FROM AUTHOR]

The present paper reports on the γ-ray and C6+ ion beam induced effect on the structural and luminescence properties of Eu doped LiNaSO4 phosphors synthesized via wet the chemical method. The material was irradiated by 60Co and 137Cs γ-rays and 75 MeV C6+ ions in a fluence range varying from 2 × 1010 to 1 × 1012 ion per cm2. The ion induced modified properties were investigated using X-ray diffraction (XRD), micro-Raman spectroscopy, photoluminescence (PL), thermoluminescence (TL) and electron paramagnetic resonance (EPR) studies. The XRD and micro-Raman results confirm the loss of crystallinity and elongation of the lattice parameters after ion beam irradiation. The presence of both divalent as well as trivalent states of Eu ions at multiple sites of LiNaSO4 is observed by PL study. Irradiation of the LiNaSO4:Eu phosphor with a C6+ ion beam modifies the population of the valence state of the doped rare earth Eu ion and enhances the TL sensitivity of this phosphor. The nature of the prominent TL glow curve is identical for both γ-ray and C6+ ion beam irradiated materials while additional deep trap levels appear in the latter due to the formation of several types of cation and anion vacancy. The electron paramagnetic resonance (EPR) technique also supports the presence of the Eu ion at multiple sites and provides information regarding several types of radical produced after γ-ray and C6+ ion irradiation. Finally, a mechanism is presented for the thermally stimulated luminescence phenomenon on the basis of our observed results from the PL, TL and EPR studies. The reason behind ion beam irradiation induced modification of the TL properties and enhancement of luminescence intensity is also explained in this report. [ABSTRACT FROM AUTHOR]

The K2Mg(SO4)2:Eu phosphor, synthesized by a solid-state diffusion method, was studied for its photoluminescence (PL) and thermoluminescence (TL) characteristics. The X-ray diffraction (XRD) pattern of the material was matched with the standard JCPDF No. 36-1499. For PL characteristics, K2Mg(SO4)2:Eu2+ showed an emission peak at 474 nm when excited at 340 nm, while it showed Eu3+ emission at 580 nm, and 594 nm splitting at 613 nm and 618 nm for an excitation of 396 nm wavelength due to radiative transitions from 5D0 to 7Fj (j = 0, 1, 2, 3). The Commission International de I′ Eclairage (CIE) chromaticity coordinates were also calculated for the K2Mg(SO4)2:Eu phosphor, and were close to the NTSC standard values. For the TL study, the prepared sample was irradiated using a 60Co source of γ-irradiation at the dose rate of 0.322 kGy/h for 2 min. The formation of traps in K2Mg (SO4)2:Eu and the effects of γ-radiation dose on the glow curve are discussed. Well defined broad glow peaks were obtained at 186°C. With increasing γ-ray dose, the sample showed linearity in intensity. The presence of a single glow peak indicated that there was only one set of traps being activated within the particular temperature range. The presented phosphors were also studied for their fading, reusability and trapping parameters. There was just 2% fading during a period of 30 days, indicating no serious fading problem. Kinetic parameters were calculated using the initial rise method and Chen's half-width method. Activation energy and frequency factor were found to be 0.77 eV and 1.41 × 106 sec−1. [ABSTRACT FROM AUTHOR]

A series of single-phase phosphors based on Na6Mg(SO4)4 (Zeff = 11.70) doped with Dy and Eu was prepared by the wet chemical method. The photoluminescence (PL) and thermoluminescence (TL) properties of Dy3+- and Eu3+-activated Na6Mg(SO4)4 phosphors were investigated. The characteristic emissions of Dy3+ and Eu3+ were observed in the Na6Mg(SO4)4 host. The TL glow curve of the Na6Mg(SO4)4:Dy phosphor consisted of a prominent peak at 234°C and a very small hump at 158°C. The TL sensitivity of the Na6Mg(SO4)4:Dy phosphor was found to be four times less than the commercialized CaSO4:Dy phosphor. The TL dose-response of the Na6Mg(SO4)4:Dy phosphor was studied from a dose range of 5-10 kGy and the linear dose-response was observed up to 1 kGy which is good for a microcrystalline phosphor. Trapping parameters for both the samples were calculated using the Initial Rise and Chen's peak shape methods. [ABSTRACT FROM AUTHOR]

Photoluminescence (PL) and thermoluminescence (TL) properties of rare earth (RE) ion (RE = Dy3+, Sm3+, Ce3+, Tb3+) activated microcrystalline BaMgP2O7 phosphors are presented in this work. Non-doped and doped samples of BaMgP2O7 were prepared using a solid state diffusion method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), PL and TL. The XRD measurement confirmed the phase purity of the BaMgP2O7 host matrix. The average particle size was found through SEM measurement to be around 2 μm. All activators using the PL technique displayed characteristic excitation and emission spectra that corresponded to their typical f → f and f → d transitions respectively. Thermoluminescence measurements showed that BaMgP2O7:RE (RE = Dy3+, Sm3+, Tb3+, Ce3+) and co-doped BaMgP2O7:Ce3+,Tb3+ phosphors have also TL behaviour. [ABSTRACT FROM AUTHOR]