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We report a detailed structural analysis and properties of the photoluminescence (PL) and thermoluminescence (TL) spectra of Eu3+ and Dy3+ incorporated into novel La2MoO6 and La2Mo2O9 phosphors synthesized successfully through gel combustion synthesis. the formation of a tetragonal phase and a cubic structure were verified for La2MoO6 and La2Mo2O9 phosphors via X-ray diffraction (XRD) studies. Dy doped samples exhibited blue and green emissions at 480 nm (F-4(9/2) -> H-6(15/2)) and 572 nm (F-4(9/2) -> H-6(13/2)), and also Eu doped samples showed a sharp emission peaks at 612 and 619 nm (D-5(0) -> F-7(2)) upon 349 nm pulse laser excitation. Peak shape (PS) technique was utilised to determine activation energy, frequency factor and order of kinetics associated with the main glow curves in undoped and Eu and Dy doped samples after X-ray irradiation. the present findings suggest that Eu and Dy incorporated La2MoO6 and La2Mo2O9 phosphors are highly auspicious candidates for applications in solid-state lighting.

In this study, the thermoluminescence (TL) characteristics of Ag-doped and undoped lithium tetraborate (Li2 B4 O7 , LTB) materials, grown using the Czochralski method, were reported. The TL properties of LTB:Ag, such as glow curve structure, dose response, fading and reproducibility, were investigated. The glow curve of the Li2 B4 O7 :Ag single crystal consists of four peaks located at approximately 75, 130, 190 and 275°C; in undoped LTB, the single crystal shows a broad glow curve with peaks at 65, 90, 125, 160 and 190°C using a heating rate of 5°C/s in the 50-350°C temperature region. The high temperature peak of Ag-doped sample at 275°C has a nonlinear dose response within the range from 33 mGy to 9 Gy. There is a linear response in the range of 33-800 mGy; after which, a sublinear region appears up to 9 Gy for Ag-doped LTB single crystal. For undoped single crystal, the dose response is supralinear for low doses and linear for the region between 1 and 9 Gy. The thermal fading ratio of the undoped material is almost 60% for the high temperature peak after 7 days. Ag-doped LTB single crystal exhibits different behaviour over a period of 7 days.

WOS: 000378835200012, In this study, manganese (Mn) doped Calcium Tetraborate (CaB4O7) samples were prepared by the wet chemical method. Under beta irradiated, CaB4O7:Mn showed thermally stimulated luminescence (TSL) glow peaks at approximately 85 degrees C and 220 degrees C with a heating rate of 5 degrees C/s. Peak shape (PS) and various heating rates (VHR) methods were applied for determining the trap parameters such as order of kinetic (b), activation energy (E) and frequency factor (s). The results indicate that the main dosimetric peak of CaB4O7:Mn follows the second-order kinetic model. The thermal fading ratio of the material is around 15% at the end of one month period of storage. The results of the TL studies carried out on the CaB4O7:Mn dosimeter revealed that it has high sensitivity, which makes it very valuable in various dosimetric applications like space, medical, personal dosimetry and dating. Radioluminescence (RL) of CaB4O7:Mn was also studied. It is shown that the RL spectrum contains a wide band centered at 530 nm assigned to Mn2+ ion emission. A broad band emission feature peaked at 350 nm assigned to the non-bridging oxygen hole center (NBOHC) is also discussed and a model is proposed to explain this broad band feature. (C) 2016 Elsevier B.V. All rights reserved.

WOS: 000374605100014, PubMed ID: 26943903, In this paper, the influence of a series of rare earth (Eu, Tm, Nd) and Cr ion doping on the optical properties of BGO was investigated by means of photoluminescence (PL) from visible to IR region in the 10-300 K temperature range using different types of detectors, namely, photomultiplier tube (PMT), InGaAs (IGA), and Si. Several samples were investigated having dopants concentrations of 03 wt%Nd, 0.4 wt%Tm, 0.06 wt% Cr and 3 ppm Eu. The PL spectra of the samples showed different luminescence behaviour which is assigned to the 4f intra shell transition from rare earth ions. The temperature dependence of the PL from rare earth doped BGO crystals is also examined. (C) 2016 Elsevier Ltd. All rights reserved.

WOS: 000352663500055, The physical characterization and phosphor emission spectra are presented for CaSO4 doped with Tm and Cu. All spectral wavelengths are related to electronic transitions of Tm3+ ions. The powder X-ray diffraction pattern showed that the compound exhibits orthorhombic structure and all reflections were indexed without any other secondary impurity phases. Chemical and structural properties of the samples have been characterized by means of Raman spectroscopy and environmental scanning electron microscope (ESEM) with an attached X-ray energy dispersive system (EDS). Group frequencies concept is essential point to the interpretation of the bands due to the main SO4 vibrational units and these displayed main characteristic intensive Raman bands including typical strong intensity at 1016 cm(-1) that corresponds to v(1)SO(4) vibrational mode. From the spatially-resolved cathodoluminescence (CL) spectrum, main emission bands of Tm3+ centered at 346, 362, and 452 nm, due to the respective transitions of P-3(0) -> H-3(4), D-1(2) -> H-3(6), D-1(2) -> F-3(4) were clearly identified. The study is novel as no such CL-ESEM data are available for this doped compound. (C) 2015 Elsevier B.V. All rights reserved., TUBITAK - HAS European Scientific Exchange Program [2227], This research is partly supported by the grants from TUBITAK - HAS European Scientific Exchange Program (2227). The authors would like to thank Dr. I. Kasa from Centre for Energy Research, Hungary for the phosphor materials.

Thermally stimulated luminescence glow curves of CaB4O7:Dy samples after β-irradiation showed glow peaks at ~335, 530 and 675 K, with a heating rate of 2 K/s. The main peak at 530 K was analyzed using the Tmax-Tstop method and was found to be composed of at least five overlapping glow peaks. A curve-fitting program was used to perform computer- ized glow curve deconvolution (CGCD) analysis of the complex peak of the dosimetric material of interest. The kinetic param- eters, namely activation energy (E) and frequency factor (s), associated with the main glow peak of CaB4O7:Dy at 520 K were evaluated using peak shape (PS) and isothermal luminescence decay (ILD) methods. In addition, the kinetics was determined to be first order (b =1) by applying the additive dose method. The activation energies and frequency factors obtained using PS and ILD methods are calculated to be 0.72 and 0.72 eV and 8.76 × 10 5 and 1.44 × 10 6 /s, respectively. Copyright © 2014 John Wiley & Sons, Ltd.

The kinetic parameters of a newly developed Li2B4O7:Mn single crystal phosphor have been presented. Li2B4O7 single crystal doped with Mn were grown via the Czochralski method. Thermoluminescence (TL) glow curve of Li2B4O7:Mn single crystal exhibits two well separated TL peaks at about 363 and 478 K, later being more intense, with a heating rate of 1 K/s. The high-temperature glow curve at 478 K is important for dosimetric studies of Li2B4O7 (LBO) doped with Mn. The kinetic parameters (activation energy (E), frequency factor (s) and kinetic order (b)) of the main glow peak (478 K) have been calculated using initial rise (IR), isothermal decay (ID) and peak shape (PS) methods. Activation energies obtained by IR, ID and PS were found to be 1.24, 1.18 and 1.20 eV, respectively. Similarly, the frequency factors were determined using isothermal decay and peak shape methods and found as 7.85 x 10(11) and 3.27 x 10(11) s (1), respectively. All results obtained using these methods are compared and discussed. (C) 2013 Elsevier B. V. All rights reserved.

In this study, thermoluminescence (TL) characterization of newly developed Li2B4O7:Mn single crystal phosphor is reported. It is a very attractive material in personal dosimetry because of its near tissue equivalency (Z(eff) = 7.25). The crystal was grown by the Czochralski method from high purity compounds. Glow curve, dose response, and fading and reproducibility properties of this material were investigated. Its TL glow curve showed two well separated peaks at about 105 and 220 degrees C with a heating rate of 2 degrees C s(-1). The main peak at 220 degrees C has a linear dose response of up to 60 Gy. The thermal fading ratio of the material is about 8% for the main peak in 10 days. The results showed that there is no significant variation of TL responses for 15 sequential measurements. Apart from the dosimetric properties above, the TL kinetic parameters of the main peak at 220 degrees C of Li2B4O7:Mn single crystal phosphor were also calculated using the various heating rates method. Activation energy and frequency factor were found as 1.21 eV and 3.75 x 10(11) s(-1), respectively. (C) 2013 Elsevier Ltd. All rights reserved.

WOS: 000324823000018, In the present study, the structural and optical properties of SrSnO3 doped with Tb ions are reported. Novel SrSnO3:Tb3+ phosphors were conventionally synthesized using a solid state reaction process under a mildly reduced atmosphere (5% H-2 and 95% N-2). The crystal structures, morphologies and optical properties of the resultant materials have been characterised by experimental techniques such as X-ray Diffraction (XRD), Raman spectroscopy (RS), Photoluminescence (PL), Radioluminescence (RL) and Cathodoluminescence coupled to an ESEM (ESEM-CL). The new phosphor material has good crystallization without any impurity phases, which matches with the standard JCPDS files (No. 22-1442) from XRD analysis. The PL, RL and CL measurements taken at room temperature showed that the transitions of D-5(4) to F-7(J) (j = 6, 5, 4, 3) corresponding to the typical 4f -> 4f dipole forbidden intra-configurational transitions of Tb3+ are largely independent of the host material. The green emissions of the D-5(4) -> F-7(5) magnetic dipole transition at similar to 540 nm are predominant for three types of luminescence. PL emission spectra recorded in the temperature range from 10 K to 300 K were influenced by temperature. We report anomalies in the PL spectra of SrSnO3:Tb3+ compatible with a structural phase transition at 260 K while simultaneously exciting and cooling the sample. This work clearly confirms the existence of a phase transition discovered by Singh et al. in SrSnO3 at 270 K. (C) 2013 Elsevier B.V. All rights reserved.

In this study, manganese (Mn) doped Calcium Tetraborate (CaB4O7) samples were prepared by the wet chemical method. Under beta irradiated, CaB4O7:Mn showed thermally stimulated luminescence (TSL) glow peaks at approximately 85 °C and 220 °C with a heating rate of 5 °C/s. Peak shape (PS) and various heating rates (VHR) methods were applied for determining the trap parameters such as order of kinetic (b), activation energy (E) and frequency factor (s). The results indicate that the main dosimetric peak of CaB4O7:Mn follows the second-order kinetic model. The thermal fading ratio of the material is around 15% at the end of one month period of storage. The results of the TL studies carried out on the CaB4O7:Mn dosimeter revealed that it has high sensitivity, which makes it very valuable in various dosimetric applications like space, medical, personal dosimetry and dating. Radioluminescence (RL) of CaB4O7:Mn was also studied. It is shown that the RL spectrum contains a wide band centered at 530 nm assigned to Mn2+ ion emission. A broad band emission feature peaked at 350 nm assigned to the non-bridging oxygen hole center (NBOHC) is also discussed and a model is proposed to explain this broad band feature.

WOS: 000309079000005, Ceramic findings collected from YeAYilova Hoyuk located in Izmir were dated using the thermoluminescence dating technique. The area is of significant archaeological importance since it is the first prehistoric settlement in Izmir. Recent archeological observations suggest that human occupation of the region took place about 8500 years ago comparing to previously determined dates of 5000 years. Three samples collected from the same archaeological layer (Neolithic period) in YeAYilova Hoyuk were dated using the thermoluminescence method. Archaeological doses (AD) were obtained by single aliquot regenerative dose method (SAR) for thermoluminescence (TL) using coarse grain quartz minerals extracted from samples. Thick and thin Al2O3:C thermoluminescence dosimeters (TLD) were used to determine the annual dose rate. The archaeological doses were found to vary from 25.91 +/- 0.78 to 26.82 +/- 0.68 Gy, and the annual doses were found to be between 3.34 +/- 0.24 and 3.47 +/- 0.24 mGy/a. The ages obtained for the samples were determined to be 6000 +/- 830 BC, 5740 +/- 670 BC and 5460 +/- 740 years for samples ND1, ND2 and ND3, respectively, which supports the prediction of archeologist that the sampling layer dates from the Neolithic period., Scientific and Technical Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TBAG 104T139]; Ege University Science and Technology Research Center (EBILTEM)Ege University [2007/BIL/020], The work described here was financially supported by grants from the Scientific and Technical Research Council of Turkey (TUBITAK-Contract No: TBAG 104T139) and Ege University Science and Technology Research Center (EBILTEM) Contract No: 2007/BIL/020. We would like to thank to Professor H.Y. Goksu for her valuable suggestions and contributions, and to Dr. A. Rowlands for English language editing.

Yttrium tantalate (YTaO4), yttrium niobium-tantalate (YTaNbO4), yttrium niobate (YNbO4), europium and terbium activated yttrium tantalate (YTaO4:Eu, YTaO4:Tb) and europium activated yttrium niobate (YNbO4:Eu) phosphors were prepared by solid-state reaction, from a homogeneous mixture consisting of Y2O3, Eu2O3, Tb4O7, Ta2O5, Nb2O5 and Na2SO4 as flux. Photoluminescence (PL), thermally stimulated luminescence (TSL), X-ray diffraction (XRD) and scanning electron microscopy (SEM) of yttrium tantalate based phosphors are reported. In the present study TSL characteristics of these phosphors were first investigated and reported after exposure to beta, UV (311 nm) and X-ray radiations.

In this study, thermal properties and thermal decompositions of dehydration behaviour of gem-quality translucent blue chalcedonies, without banding or crystalline centre structure, from the Sancakaya-Eskisehir region in Turkey were studied by means of X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectrometry (ICP-AES), Fourier transform infrared (FT-IR), thermoluminescence (TL), and simultaneously two thermal analyses of (DTA/TGA) spectroscopy. X-ray diffraction patterns of the blue chalcedony indicate the presence of two important chalcedonic silica phases with overlapped peaks at 4.26, 3.34, 2.28, 2.13, 1.82, 1.54, 1.38, and 137 A. During heating from the room temperature to 300 degrees C, the thermoluminescence pattern of the blue chalcedony shows a characteristic peak at 210 degrees C. This peak may be due to unusually high traces of the impurities S. Th, TI, U, and W. During heating from the room temperature to 1400 degrees C, the TGA pattern of the blue chalcedony indicates that the weight loss is due to the silanol water loss only, and that this loss occurs in a wide temperature range between about 170 and 954 degrees C. In addition, after making some corrections concerning the artefact mass gain, being due to the drift with buoyancy effect of the atmosphere in its TGA curve, the moganite-rich blue chalcedony shows a relatively lower mass loss of 0.202%. The DTA pattern of the blue chalcedony displays both endothermic and exothermic behaviours because of silica phase transformations. There are one distinctive sharp endotherm and three weaker endotherms at 806 degrees C. In addition, there is one distinctive sharp exotherm and one weaker exotherm at 1270 degrees C. (C) 2010 Elsevier B.V. All rights reserved.

Borate based thermoluminescence dosimeters (TLD) show high sensitivity and good TL characteristics. One of the promising material amongst the dosimeters is Dy doped CaB4O7. Spectrally resolved thermoluminescence of Dy doped CaB4O7 shows three glow peaks at about 50 degrees C, 240 degrees C and 380 degrees C, the intensity of the 240 degrees C glow peak being the maximum. All TL experiments were conducted on a high sensitivity TL spectrometer at Sussex University with a heating rate of 50 degrees C min(-1). Two main emissions associated with the Dy dopant are observed at similar to 480 and 580 nm. The samples were subjected to a series of treatments including excitation by X-rays and UV laser radiation. As part of the present research CaB4O7:Dy materials were subjected to two different heat treatments; quenching and slow cooling in order to investigate the changes in TL characteristics. (C) 2010 Elsevier Ltd. All rights reserved.

Room and low temperature cathodoluminescence (CL) of rare earth doped Bi4Ge3O12 (BGO) has been recorded. Luminescence signals noted in the wavelength range (300–800 nm) include intrinsic broad emission bands and signals related to Eu3+, Nd3+, and Tm3+. CL measurements made on Bi4Ge3O12 (BGO) doped with rare earth ions are reported for the temperature range 40 to 300 K with different CL excitation modulation frequencies. Dopant levels used in the present study are 1.1, 0.4, and 0.3 wt% Nd, 0.4 wt% Tm and 3 ppm Eu. All dopant levels exhibited different CL spectra with evidence for lines due to the rare-earth dopants intra-4f transitions. The temperature dependence of the intensity of the emission band is discussed.

Rare earths, especially Dy or Tm doped CaSO4 phosphors are actively studied. They have high sensitivity, a large dynamic range, thermal stability and ease of preparation. Nevertheless, they can be enhanced by inclusion of lithium and this study reports some effects of lithium co-dopant on the TL and radioluminescence (RL) emissions of two TL phosphors. Addition of Li as a co-dopant ion was made either during chemical preparation of the phosphors, or as a binder component mixed with the basic phosphors matrix during the process of pressing and sintering the TLD pellets.

The aim of this study is to compare Intensity Modulated Radiation Therapy (IMRT) plan of prostate cancer patients with different dose verification systems in dosimetric aspects and to compare these systems with each other in terms of reliability, applicability and application time. Dosimetric control processes of IMRT plan of three prostate cancer patients were carried out using thermoluminescent dosimeter (TLD), ion chamber (IC) and 2D Array detector systems. The difference between the dose values obtained from the dosimetric systems and treatment planning system (TPS) were found to be about % 5. For the measured (TLD) and calculated (TPS) doses %3 percentage differences were obtained for the points close to center while percentage differences increased at the field edges. It was found that TLD and IC measurements will increase the precision and reliability of the results of 2D Array. © 2016 AIP Publishing LLC.

WOS: 000379559700017, PubMed ID: 27235885, Here, we report our results referring to the preparation of Ce doped Y2.22MgGa2Al2SiO12, Y1.93MgAl4SiO12 and Y2.22Gd0.75Ga2Al3O12 using solid state reaction at high temperature. Several complementary methods (i.e. powder x-ray diffraction (XRPD), energy dispersive analysis of X-rays (EDX), scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FTIR)) were studied to examine the effects of the synthesis procedure on the morphology and structure. XRD analyses revealed that all compounds include yttrium aluminate phase with garnet structure. Cathodoluminescence (CL), radioluminescence (RL) and photoluminescence (PL) measurements were carried out for clarification of relationship between host lattice defects and the spectral luminescence emissions. Luminescence emission of phosphors is peaked at 530 nm assigned to 5d-4f transitions of the dopant Ce3+ ions with a broad emission band in 400-700 nm range. Under electron irradiation, the emission spectrum of Ce doped (YGd)(3)Ga2Al3O12 is well defined and has a characteristic fairly narrow and sharp emission band peaking at 312 nm and 624 nm corresponding to transition of P-6(7/2) -> S-8(7/2) and (6)G(J) -> P-6(J) (Gd3+), respectively. We suggest some of phosphors might be excellent phototherapy phosphor materials under electron excitation. (C) 2016 Elsevier Ltd. All rights reserved., Romanian National Authority for Scientific Research, CNCS - UEFISCDI [PN-II-RU-TE-2012-3-0360], This work was supported by a grant of the Romanian National Authority for Scientific Research, CNCS - UEFISCDI, project number PN-II-RU-TE-2012-3-0360.

WOS: 000377737500004, PubMed ID: 27108070, Thermoluminescence (TL) glow curves of pure and rare earth doped bismuth germanate (BGO) were investigated under UV and beta radiation. The glow curves of pure BGO crystal present different patterns for both kinds of radiation. The TL glow curves of BGO crystals doped with Nd ions are similar to that of pure BGO under UV radiation. The kinetic parameters, kinetic order (b), activation energy (E) and frequency factor (s) of the TL glow curves of pure BGO crystal have been determined by peak shape method. Activation energies of 3 peaks obtained by PS were found to be 1.81, 1.15 and 1.78, respectively. (C) 2016 Elsevier Ltd. All rights reserved.

WOS: 000369581800062, Herein, we primarily focus on luminescence spectrum measurements of various types of green emitting yttrium aluminate phosphors modified with gallium (Y3Al5-xGaxO12) synthesised by solid state reaction. The luminescent emission of samples depends on sample temperature and excitation radiation such as incident X-ray, electron and laser beam. Here, we measured radioluminescence (RL), cathodoluminescence (CL), photoluminescence (PL) along with XRD in order to clarify relationship between lattice defects and the spectral luminescence emissions. The RL and CL spectra of YAG:Ce exhibit an emission band ranging from 300 to 450 nm related to Y-Al antisite defects. The broad emission band of garnet phosphors is shifted from 526 nm to 498 nm with increasing of Ga3+ content, while full width at half maximum (FWHM) of the band tends to be greater than the width of unmodified YAG: Ce garnet. Deconvolution of the spectrum reveals that three emission bands centred at 139, 234 and 294 degrees C occur in aluminate host garnets. (C) 2016 Elsevier B.V. All rights reserved.

The kinetic parameters of a newly prepared tissue-equivalent, highly sensitive thermoluminescent detector, Li 2 B 4 O 7 : Cu , Ag , P of sintered pellets have been calculated. Thermoluminescence (TL) glow curves of Li 2 B 4 O 7 : Cu , Ag , P samples after β -irradiation showed peaks at about 384 and 446 K with a heating rate of 1 K s - 1 . The kinetic parameters, namely activation energy ( E ) and frequency factor ( s ) associated with the main glow peak (446 K) of Li 2 B 4 O 7 : Cu , Ag , P have been determined using isothermal decay (ID) and peak shape (PS) methods. The activation energies obtained by ID and PS methods are calculated to be 1.12 and 1.13 eV (mean), respectively. The frequency factors obtained by both methods are 7.61 × 10 11 and 3.53 × 10 11 s - 1 (mean), respectively. Results obtained using both methods are compared and discussed.

ZnO [0001] single crystals were implanted at room temperature with 400 keV Tb + ions at fluences in the range of 1 × 10 16 –2 × 10 17 ions/cm 2 . Zinc oxide was chosen because of its potential for photonic applications as a semiconductor with high radiation resistance. After implantation and post-irradiation annealing, optical absorption was measured in a UV–VIS–NIR range and radioluminescence spectra were recorded at room temperature. Emission signals were generated by the Tb + ion implants and intrinsic emission of the ZnO matrix were observed. The implant signal intensities were comparable with the host radioluminescence, even though the implants modify the surface of the crystal. It is suggested that the presence of Tb at high concentration generates stresses which influence the bulk material and also potentially forms precipitates or nanoparticles in the near surface region. Overall ion implantation of ZnO results in strongly modified luminescence.

The effect of heating rate on the thermally stimulated luminescence (TSL) emission due to the temperature lag (TLA) between the TSL material and the heating element has been investigated using Li2B4O7:Cu,Ag,P dosimetric materials. The TLA becomes significant when the material is heated at high heating rates. TSL glow curves of Li2B4O7:Cu,Ag,P material showed two main peaks after beta-irradiation. The kinetic parameters, namely activation energy (E) and frequency factor (s) associated with the high temperature main peak of Li2B4O7:Cu,Ag,P were determined using the method of various heating rates (VHR), in which heating rates from 1 to 40 K s(-1) were used. It is assumed that non-ideal heat transfer between the heater and the material may cause significant inconsistency of kinetic parameter values obtained with different methods. The effect of TLA on kinetic parameters of the dosimeter was examined.

The aim of this study is to determine the enhancement in natural radioactivity level of soils due to the usage of fertilizers, particularly phosphate fertilizers in agricultural lands of Gediz River basin, Western Turkey. In addition, the activity concentrations of naturally occurring radionuclides in some vegetables collected from the same lands were investigated in order to assess any contribution to the effective internal dose after ingestion. Radioactivity concentrations of natural radionuclides, namely Ra 226 , Th 232 and K 40 , in fertilized, non-fertilized soils and vegetables were measured by NaI(Tl) gamma spectrometer in order to assess the implications of the extended use of phosphate fertilizers in agriculture in recent years. Activity concentration of Po 210 , an alpha particle emitter, were also analysed using a ZnS(Ag) alpha counter after electrodeposition process. In addition, physical and chemical characteristics of soil samples were investigated and analysed for any correlation between the soil characteristics and their radionuclide contents. In vegetables collected from agricultural fields of the basin the ranges of the relative activity concentrations of K 40 , Ra 226 , Th 232 and Po 210 are found to be 491.62–2324.51, 15.96–52.80, ND–10.54 and 8.40 – 22.20 Bq kg - 1 , respectively. In soils of agricultural lands, where vegetables are collected, the activity concentrations of K 40 , Ra 226 , Th 232 and Po 210 are 325.89–530.52, 46.05–68.83, 9.29–50.57 and 36.75 – 56.70 Bq kg - 1 , respectively. For non-fertilized fields, activity concentrations of soils are found to be within 240.40 – 403.09 Bq kg - 1 for K 40 , 35.61 – 62.64 Bq kg - 1 for Ra 226 , 7.40 – 38.53 Bq kg - 1 for Th 232 and 32.50 – 41.14 Bq kg - 1 for Po 210 .

Nanoparticles of Cu have been made in zinc oxide crystals by ion implantation. The Cu ions were implanted at 400 keV into the (0 0 0 1) face of a single crystal. After implantation and after post-irradiation annealing there are numerous changes in the luminescence responses which include a variety of green and yellow emission bands. Following annealing at temperatures up to 1000 °C a green luminescence near 525 nm was observed which has been associated with the isolated Cu ions. The changes between as implanted and annealed luminescence signals suggests that the implants generate clustering or nanoparticle formation of Cu but anneals dissociate them.

Key characteristics of a newly prepared tissue-equivalent, highly sensitive thermoluminescence dosimeter, Li2B4O7:Cu,Ag,P, are presented. The material was developed at the Institute of Nuclear Sciences, Belgrade, in the form of sintered pellets. A new preparation procedure has greatly increased the sensitivity of the basic copper activated lithium borate and the glow curve of Li2B4O7 : Cu,Ag,P consists of a well-defined main dosimetric peak situated at about 460–465 K with a sensitivity which is about four to five times higher than that of LiF : Mg,Ti (TLD-100). The exceptionally good response features of Li2B4O7 : Cu,Ag,P are attributed to the incorporation of Cu as a dopant. Both low and high temperature emission spectra are presented and the origins of the various emission bands are considered. Additional data are provided from electron paramagnetic resonance measurements.

Dosimeters of MgB4O7 doped with Dy and Na have many valuable features such as high sensitivity, tissue equivalence, low fading, non-requirement of annealing and insensitivity to light. Thermoluminescence studies of Dy and Na doped MgB4O7 samples showed that a glow emission peaked at about 195 degrees C. In this study, the trapping parameters associated with the main dosimetric peak, namely at 195 degrees C, of Dy and Na doped MgB4O7 are investigated. Isothermal luminescence decay, glow curve shape, initial rise (linear regression) and T-m - T-stop methods were used. We report the results on the kinetic behaviour and activation energy determination of the peak occurring at 195 degrees C with a moderate heating rate of 2 degrees C s(-1). The average activation energies obtained by the isothermal luminescence decay method, glow curve shape method and initial rise method are calculated to be 1.03 eV, 0.95 eV and 0.89 eV, respectively. The methods mentioned above indicate that the dosimetric peak may consist of one or more second-order components. The frequency factors obtained by the three methods are 3.5 x 10(10) s(-1), 1.6 x 10(9) s(-1) and 3.4 x 10(8) s(-1),respectively. Results obtained using all these methods are compared and discussed.

In this study concentrations of 210Po and 210Pb radionuclides in soils and vegetables collected from both cultivated and uncultivated agricultural lands of the Kucuk Menderes basin were determined. 210Po and 210Pb activity concentrations of vegetables collected from cultivated lands were found to be slightly higher than those collected from undisturbed lands. The activity concentrations in vegetables were detected between 0.15 – 9.40 Bq kg - 1 and 0.23 – 0.62 Bq kg - 1 for 210Po and 210Pb, respectively. In the bulk soil cores sampled from phosphate fertilizer-applied agricultural lands, the ranges for activity concentrations of 210Po and 210Pb are 30.10 – 47.15 Bq kg - 1 and 31.27 – 61.53 Bq kg - 1 , respectively. 210Po and 210Pb activity concentrations in soil cores collected from uncultivated soils were also determined for comparison. The annual effective dose equivalents to man from 210Po and 210Pb due to consumption of leafy vegetables are calculated to be 30.51 and 22.73 μ Sv a - 1 , respectively. Likewise root vegetables give a dose equivalent of 22.89 μ Sv a - 1 from 210Po and 44.77 μ Sv a - 1 from 210Pb.

Copper nanoparticles have been formed in a zinc oxide (ZnO) substrate by Cu implantation at 160 keV. The implant layer shows amorphised behaviour as monitored by the RBS data and optical absorption indicates the surface plasmon resonance peak characteristic of copper nanoparticles. There is nonlinear optical absorption from the Cu nanoparticles. There are numerous changes in the luminescence responses which include a variety of green and yellow emission bands. During excitation there were changes in the cathodoluminescence intensity and lifetime influenced by the surface events, including some unusual features, which may be considered in terms of interactions with surface water and ice. Radioluminescence signals oscillate between the normal emission bands and the wide red line emission from free Zn. Overall ZnO is, therefore, an unexpectedly interesting host for dispersed Cu nanoparticles, not least because the optical features may be compatible with the semiconductor aspects of ZnO.

Thermoluminescence and phototransfer thermoluminescence glow curves, and the corresponding emission spectra of LiF (TLD-100) crystals were studied over the temperature range 100 to 300 K after pre-irradiation heat treatment at 373, 423 and 673 K for 1 h. The TL glow curve displays six glow peaks over this temperature range. The intensity and peak temperatures of glow peaks above 200 K are highly affected by the pre-irradiation heat treatment while the glow peaks below 200 K are not affected by this treatment. The various emission spectra include 'ultraviolet' bands at 5.42, 4.42 and 3.57 eV and 'visible' bands at 3.07, 2.65 and 2.22 eV. The first glow peak, seen at 138 K, emits in both the ultraviolet and visible with similar intensity. The next glow peak, seen at 156 K with reduced intensity, also emits in both regions but with relatively more in the ultraviolet than the visible. The peak intensity and energy of the individual visible emission bands are strongly affected by pre-irradiation heat treatment, while the ultraviolet bands are weakly affected. The data are explained with a band-gap model that extends Mayhugh–Christy's model for thermoluminescence above room temperature.

WOS: 000360513900014, PubMed ID: 26072018, In this study, structural and luminescence properties of magnesium borate of the form MgB4O7 doped with Tm and Na were investigated by X-ray diffraction (XRD), Raman spectroscopy and cathodoluminescence (CL). The morphologies of the synthetised compounds exhibit clustered granules and road-like materials. As doping trivalent ions into a host with divalent cations requires charge compensation, this effect is discussed. The CL spectra of undoped MgB4O7 shows a broad band emission centred around 350 nm which is postulated to be produced by self-trapped excitons and some other defects. From the CL emission spectrum, main emission bands centred at 360, 455, 475 nm due to the respective transitions of D-1(2)-> H-3(6),D-1(2)-> F-3(4) and (1)G(4)-> H-3(6) suggest the presence of Tm3+ ion in MgB4O7 lattice site. CL mechanism was proposed to explain the observed phenomena which are valuable in possibility of the developing new luminescent materials for different applications. In addition, the experimental Raman spectrum of doped and undoped MgB4O7 were reported and discussed. (C) 2015 Elsevier Ltd. All rights reserved.

Structural phase transitions influence the luminescence characteristics by modifying the spectra, sensitivity and luminescence efficiency in each phase. This has implications for dosimetric materials both for sensitivity and reproducibility. Previous work with dosemeter materials has not documented effects of different phases on thermoluminescence but Na2SO4 exists in several phases in the temperature range of interest for thermoluminescence dosimetry. Therefore spectrally resolved TL and radiothermoluminescence analyses of undoped and Dy3+ doped Na2SO4 have been performed. Dramatic differences between TL of slow cooled and quenched Na2SO4:Dy are explained in terms of the initial phase of the samples at room temperature. For undoped material the effect of phase conversions during heating shift the wavelengths of the emission bands. A model of Dy in small precipitate phases is considered.

Luminescence from rare earth ions provides spectral signatures that identify the type of site. Substitution of the ions in a lattice introduces distortions scaled by the relative size of the host and dopant. For LaF3 or Bi4Ge3O12 several different co-ordination numbers are used; charge compensation is also needed in BaF2, SrF2, CaSO4 etc. When the trapping and recombination sites closely interact, the glow peak temperatures are strongly dependent on the size of the rare earth ion. Three types of pattern are noted with (i) minimal change; (ii) peak shifts scaling with RE ion size over ∼ 30 degrees or (iii) over 200 degrees from precipitate formation.

The substitution of rare-earth ions into insulating host crystals introduces lattice strains and, for non-trivalent sites, a need for charge compensation. Such effects alter the site symmetry and this is reflected in properties such as the wavelength, linewidth, lifetime and relative intensity of the rare-earth transitions. Equally clear, but less well documented, is the influence on second-harmonic generation (even from cubic crystal lattices). For example, in bismuth germanate, second-harmonic generation efficiency varies by factors of more than 100 as a result of different rare-earth dopant ions. The ions are variously incorporated as substitutional ions, pairs, clusters, or even as precipitates of new phases, but the detailed modelling is often speculative. This article summarizes some recent studies which explore the role of rare-earth ions in thermoluminescence and second-harmonic generation. There are numerous differences in glow peak temperature, for nominally the same defect sites, which are thought to indicate charge trapping and recombination within coupled defect sites, or within a large complex. Size and cluster effects can be modified by heat treatments. This review considers the similarity and trends seen between numerous host lattices which are doped with rare-earth ions. For thermoluminescence there are trends in the variation in glow peak temperature with ion size, with movements of 20 to 50 K. Examples are seen in many hosts with extreme effects being suggested for zircon, with peak shifts of 200 K (probably from precipitate phases).

Fullerenes are not automatic candidates for luminescence analyses due to their highly absorptive nature. Consequently, very few luminescence experiments have been performed on fullerenes. This paper focuses on the luminescence properties of commercially available C60 when bombarded by electrons (cathodoluminescence) and, to a lesser extent, x-rays (radio- thermoluminescence) between 20 and 270 K. Wavelength resolved luminescence signals have been recorded as a function of temperature. CL experiments reveal pronounced anomalies that truncate the emission spectrum between 155 and 170 K. Other less pronounced anomalous features are detected at 70 and 245 K. These dramatic changes in the luminescence spectra are cautiously interpreted to be manifestations of phase transitions and support the view that cathodoluminescence (CL) can be used to monitor for phase transitions in fullerenes. The luminescence signals offer information on the mechanisms of the relaxation processes, including changes in charge trapping energies and emission spectra.

The radioluminescence and thermoluminescence spectra of synthetic zircon crystals doped with individual trivalent rare earth element (REE) ions (Pr, Sm, Eu, Gd, Dy, Ho Er, and Yb) and P are reported in the temperature range 25 to 673 K. Although there is some intrinsic UV/blue emission from the host lattice, the dominant signals are from the rare-earth sites, with signals characteristic of the REE3+ states. The shapes of the glow curves are different for each dopant, and there are distinct differences between glow peak temperatures for different rare-earth lines of the same element. Within the overall set of signals there are indications of linear trends in which some glow peak temperatures vary as a function of the ionic size of the rare earth ions. The temperature shifts of the peaks are considerable, up to 200°, and much larger than those cited in other rare-earth-doped crystals of LaF3 and Bi4Ge3O12. The data clearly suggest that the rare-earth ions are active both in the trapping and luminescence steps, and hence the TL occurs within localized defect complexes that include REE3+ ions.

Thermoluminescence (TL) and radio-thermoluminescence spectral analysis techniques have been applied to doped calcium sulphate samples designed for radiation measurements at elevated temperatures. CaSO4 :Dy, when co-doped with Ag, provides a TL dosimetric peak near 350 °C which is useful for radiation measurements at high temperatures. Dopants of Ce, Mn and Dy variously move the peak temperature from 400 °C to 200 °C. Each dopant ion gives a characteristic emission spectra, which for CaSO4 :Ce, Mn samples indicate that there is a systematic temperature difference of ~7 °C between the glow peaks from the Ce and Mn sites. The CaSO4 :Dy samples show a discontinuity in the emission wavelength from the Dy ions near T = 200 °C and a decrease in the radioluminescence fluorescence in the same temperature region. In each case it is proposed that the dopants form part of large, complex defects, instead of isolated trapping and recombination centres. The data offer further evidence for a localized phase transition of the defect complex at 200 °C. Low-temperature data, from 20 K, show similar differences in the peak temperature from the various dopants and additionally indicate reproducible discontinuities in the wavelength positions and intensities, for all samples, at T = 230 K. This again suggests structural phase adjustments of the defect sites.

Thermoluminescence was originally modelled in terms of highly localised point defects with independent trapping and recombination sites. Neither concept is now throught to be appropriate and data are presented which indicate the scale of defect complexes, within which thermoluminescence occurs where long range interactions are often evident. The present views are strongly supported by data from thermoluminescence emission spectra. For example, the glow peak temperatures of emission from different rare earth ions depend on the dopant, implying that the trap and recombination centre are spatially linked. In LaF3 there are examples of peak shifts of up to 18 K which depend directly on the ionic radii of the rare earth ions. Similar data from other systems are noted, all of which underpin models of thermoluminescence generated by internal charge transfer within very large defect complexes.

Thermoluminescence analysis is a sensitive technique for studies of imperfections in insulators and in radiation dosmietry. Natural minerals, and many synthetic materials, are often spatially non-uniform in their optical emission and knowledge of such features is essential for modelling of the thermoluminescence processes. To quantify such problems a Photek photon imaging camera has been added to the Sussex TL system. Data show examples of (i) zones of high intensity emission, even when there are no obvious anomalies in the emission spectra; (ii) differences between the uniformity of radioluminescence and thermoluminescence; (iii) resolution of signals from multi-mineral mixtures, and (iv) evidence of discharging zones from pyroelectrics. Examples of such data are presented.

Thermoluminescence radiation dosimetry of geological or archaeological materials, for age determinations, is susceptible to errors caused by non-uniformity of the samples. Even in synthetic dosemeters there can be problems of non-uniformity, or of cross contamination between samples. In order to observe the uniformity of the dosimetry from the samples a Photek photon imaging camera has been installed on a spectrally resolved thermoluminescence system. Data obtained in this way clearly relate problem samples to zones of high intensity emission, even when there are no obvious anomalies in the emission spectra. Additionally, the pattern and uniformity of radioluminescence can differ from that of thermoluminescence. Non-uniformity from multi-mineral mixtures can be correlated with emission spectra in those cases where there are clear differences between the spectra of the components. The imaging camera performance is comparable with the sensitivity of normal TL detection and clear dynamic images are obtained during the TL from borates or sulphates following radiation doses of

Wavelength resolved spectra of the dosimetric materials CaSO4 and MgB4O7 with the rare earth (RE) ions Dy and Tm are presented. The study of co-doped samples provides, within a single sample, unequivocal evidence of a glow peak displacement of the two dopants. In the case of the main dosimetric peak for CaSO4 at similar to 220 degrees C, a reproducible systematic temperature difference of 7 to 8 degrees C is observed between the glow peaks near 230 to 240 degrees C for Tm and Dy. No comparable displacement is detected between Tm and Dy for the main dosimetric peak for MgB4O7 at about 180 degrees C. However, higher temperature glow peaks above 300 degrees C display a noticeable displacement of Dy and Tm on the scale of 30 degrees C. This research provides further evidence supporting the view that the RE ions could form part of a complex defect acting as both charge trap and recombination centre. 12th International Conference on Solid State Dosimetry, Jul 05-10, 1998, Burgos, Spain

Cathodoluminescence (CL) provides a sensitive analytical probe of the near-surface region of insulating materials, and some new examples of the strengths of the technique are presented using recent data from the University of Sussex. Analysis of float glass shows that by spectral and lifetime resolved data it is possible to separate the emission bands from excitonic, intrinsic imperfections, and impurities in various valence states, as a function of their depth beneath the surface. Correlation of the CL data with those from Mössbauer, ion beam and other analyses then provides the basis for models of the defect sites. CL from a second glass, ZBLAN, reveals the presence of microcrystallites and growth defects, and the work underpins confidence in the high purity gas levitation method of ZBLAN production. New results on CL of wavelength shifts with crystal field of Mn in carbonates are presented, and of Nd emission from Nd:YAG. The effects are directly linked to surface damage and dislocations caused by sample preparation steps of cutting and polishing. Methods to minimise the damage, by furnace or pulsed laser annealing, and chemical routes, are mentioned. Such surface preparation damage has a profound effect on all CL monitoring, whether for fundamental studies or mineralogical applications. Finally, a route to eliminate such problems is demonstrated, with consequent improvements in luminescence, transmission and laser performance of surface waveguides. The implications of improved surface quality range widely from mineralogical CL imaging through improved photonic materials and epitaxial growth to elimination of surface damage, and additional information.

Spectrally resolved thermoluminescence of co-doped Dy:Tm: shows that the maximum peak temperature for the nominal C dosimetry peak differs by C for Dy and Tm emission. This is interpreted as evidence that the rare earth ions form part of a complex defect which variously provides both the charge trapping and, during heating, the radiative decay. The peaks have the same activation energies but different pre-exponential factors. Modifications of the material by thermal treatments using furnace or laser pulse heating convert the state of dispersion of the rare earth ions between isolated, pair or defect clusters, which alter the dosimetry efficiency. In some cases the modified geometries are detectable via movement of the emission lines. For rapidly quenched materials, discontinuities in the thermoluminescence responses are suggested to be indicative of new microcrystalline phases. Slow cooling degrades the efficiency but also indicates the presence of further thermoluminescence glow peaks within the region of the main dosimetry signal. Pulsed laser heating with a UV laser altered the glow curve and resulted in strong signals. Mechanisms for this process are considered.

The main problem in the trans-boundary river system is that heavy metal and radioactive pollution can cause long-term effects on ecosystems. Therefore the natural radioactivity and heavy metal levels in the Maritza, Tundja and Arda Rivers, common for Bulgaria and Turkey, were determined for 3 years period (2007-2010). Gross alpha, gross beta and total radium isotopes activities, uranium and heavy metal concentrations of the surface water of the rivers were investigated and also terrestrial gamma and gamma dose rate were measured. The results were compared with reported data from other countries of the world and the recommended international standards. The results gathered in this study may provide background data on the natural radioactive and heavy metal levels of these trans-boundary rivers. © 2014 Akadémiai Kiadó.

This article represents the first results of the natural radionuclides in the Maritza and Tundja river sediments, in the vicinity of Edirne city, Turkey. The aim of the article is to describe the natural radioactivity concentrations as a baseline for further studies and to obtain the distribution patterns of radioactivity in trans-boundary river sediments of the Maritza and Tundja, which are shared by Turkey, Bulgaria and Greece. Sediment samples were collected during the period of August 2007-April 2010. The riverbank sediment samples were analyzed firstly for their pH, organic matter content and soil texture. The gross alpha/beta and 238U, 232Th and 40K activity concentrations were then investigated in the collected sediment samples. The mean and standard error of mean values of gross alpha and gross beta activity concentrations were found as 91 ± 11, 410 ± 69 Bq/kg and 86 ± 11, 583 ± 109 Bq/kg for the Maritza and Tundja river sediments, respectively. Moreover, the mean and standard error of mean values of 238U, 232Th and 40K activity concentrations were determined as 219 ± 68, 128 ± 55, 298 ± 13 and as 186 ± 98, 121 ± 68, 222 ± 30 Bq/kg for the Maritza and Tundja River, respectively. Absorbed dose rates (D) and annual effective dose equivalent s have been calculated for each sampling point. The average value of adsorbed dose rate and effective dose equivalent were found as 191 and 169 nGy/h; 2 and 2 mSv/y for the Maritza and the Tundja river sediments, respectively. © 2012 Copyright Taylor and Francis Group, LLC.

Fire opal (SiO2·nH2O) and diaspore [Al(OH)O] are two different precious and rare mineral species with high water content. While these species are being cut and polished to make gems, defect-induced weaknesses such as fragility, splintering, and cracking become apparent since the temperature of the mineral species may be increased to high temperatures during the process. These deformations may be broadly related to water loss (molecular (H2O) and hydroxyl (OH) group) and transformation of the base building components and/or inclusion minerals. In this study, thermal properties and thermal stability as dehydratial behaviors of both gem quality fire opal (SiO2·nH2O) from the Saphane region (Kutahya, Turkey) and gem quality diaspore (AlOHO) from the Milas region (Mug˘la, Turkey), including some associated mineral inclusions, were studied by means of X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform-Infrared absorption (FTIR) spectroscopy and thermal analysis (DTA/TGA). During heating to 1400 °C, DTA/TGA patterns indicated that the weight losses of the fire opal and diaspore were due to the water loss only, and that these losses occur in the temperature ranges between about 342 and 722 °C in fire opal, and between about 592 and 718 °C in diaspore. In addition, after making some corrections concerning the mass gain observed, being due to the drift with buoyancy effect of the atmosphere, in their TGA curves, the fire opal shows a mass loss of 7.942%, and one distinctive sharp endotherm at 1089.99 °C and seven weaker endotherms, whereas the diaspore shows a mass loss of about 13.826%, and one distinctive sharpest endotherm at 650.47 °C and four weaker endotherms.

In this paper the influence of different heating rates on thermoluminescence (TL) kinetics, glow-peak temperatures, heights and integrated TL intensities of the main glow peak of recently produced Mg2SiO4 : Tb dosimeters are reported. The TL properties of the phosphor were investigated after beta-irradiation at room temperature. Glow curve shape, peak shape, repeated initial rise and variable heating rate methods were used to analyse the TL kinetics of the main glow peak at 473 K. Results show that the TL glow peak of Mg2SiO4 : Tb phosphor obeys second-order kinetics. Analysis of the main dosimetric peak by using the methods mentioned above revealed that activation energy (E) is about 1 eV and the pre-exponential factor (s) is in the range 10(10)-10(11) s(-1). In addition it is ascertained that the glow-peak temperature increases with heating rate. The glow-peak height showed two maxima in the heating rate range investigated. The behaviour of the integrated TL intensities and the maximum glow-peak temperatures related to the heating rate have been discussed in terms of thermal quenching and clustering formation.

210Po in environmental samples has been accumulated on various metals using the chemical electrodeposition technique. The 210Po was deposited spontaneously on metal discs after decomposition of the sample in HCl acid and then measured using a ZnS(Ag)α-particle detector. Silver was observed to have the highest deposition efficiency when 210Po deposition on different metals was studied. Copper discs were used in the application of activity assessment in cigarette smoke as this is more available and more economical although silver has a higher efficiency than that of other materials examined. The technique is applied for the analysis of 210Po in tobacco, ash and butt for several brands of imported and domestic cigarettes smoked in Turkey.

This paper presents X ray excited TL spectra of magnesium borate doped with either single rare earth ions Dy or Tin, or co-doped with Dy/Tm, Tm/Mn or Dy/Tb. Intrinsic emission from the host material is in the UV/blue region at similar to375 nm, with a tail extending to 200 nm. The main dosimetric peak is detected at similar to180degreesC but slight differences are noted between the glow peak maxima from the different rare earth ions and there were changes following thermal treatments. The results are discussed according to the interaction between trapping and rare earth sites. 13th International Conference on Solid State Dosimetry, Jul 09-13, 2001, Athens, Greece