Turgay Karali - Academia.edu (original) (raw)

Papers by Turgay Karali

Physica B: Condensed Matter, 2010

Fire opal (SiO 2 Á nH 2 O) and diaspore [Al(OH)O] are two different precious and rare mineral spe... more Fire opal (SiO 2 Á nH 2 O) 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 (H 2 O) and hydroxyl (OH) group) and transformation of the base building components and/or inclusion minerals.

Physica B: Condensed Matter, 2010

Fire opal (SiO 2 Á nH 2 O) and diaspore [Al(OH)O] are two different precious and rare mineral spe... more Fire opal (SiO 2 Á nH 2 O) 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 (H 2 O) and hydroxyl (OH) group) and transformation of the base building components and/or inclusion minerals.

Radiation Measurements, 2007

The aim of this study is to determine the enhancement in natural radioactivity level of soils due... more 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.

Radiation Measurements, 2007

The aim of this study is to determine the enhancement in natural radioactivity level of soils due... more 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.

Physica B: Condensed Matter, 2010

ABSTRACT In this study, thermal properties and thermal decompositions of dehydration behaviour of... more ABSTRACT 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 Sarıcakaya-Eskişehir 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 Å. During heating from the room temperature to 300 °C, the thermoluminescence pattern of the blue chalcedony shows a characteristic peak at 210 °C. This peak may be due to unusually high traces of the impurities S, Th, Tl, U, and W. During heating from the room temperature to 1400 °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 °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 °C. In addition, there is one distinctive sharp exotherm and one weaker exotherm at 1270 °C.

Physica B: Condensed Matter, 2010

ABSTRACT In this study, thermal properties and thermal decompositions of dehydration behaviour of... more ABSTRACT 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 Sarıcakaya-Eskişehir 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 Å. During heating from the room temperature to 300 °C, the thermoluminescence pattern of the blue chalcedony shows a characteristic peak at 210 °C. This peak may be due to unusually high traces of the impurities S, Th, Tl, U, and W. During heating from the room temperature to 1400 °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 °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 °C. In addition, there is one distinctive sharp exotherm and one weaker exotherm at 1270 °C.

Luminescence, 2014

Thermally stimulated luminescence glow curves of CaB4 O7 :Dy samples after β-irradiation showed g... more Thermally stimulated luminescence glow curves of CaB4 O7 :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 computerized glow curve deconvolution (CGCD) analysis of the complex peak of the dosimetric material of interest. The kinetic parameters, namely activation energy (E) and frequency factor (s), associated with the main glow peak of CaB4 O7 :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.

Luminescence, 2014

Thermally stimulated luminescence glow curves of CaB4 O7 :Dy samples after β-irradiation showed g... more Thermally stimulated luminescence glow curves of CaB4 O7 :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 computerized glow curve deconvolution (CGCD) analysis of the complex peak of the dosimetric material of interest. The kinetic parameters, namely activation energy (E) and frequency factor (s), associated with the main glow peak of CaB4 O7 :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.

Radiation Measurements, 2011

Feldspar as an archaeological and geological natural material for dating and retrospective dosime... more Feldspar as an archaeological and geological natural material for dating and retrospective dosimetry is receiving more and more attention because of its useful luminescence properties. In this study, the 25–280 K thermoluminescence (TL) and radioluminescence (RL) spectra in albite, which is a component of the two main feldspar series, the alkali feldspar (Na, K)AlSi3O8 and the plagioclases (NaAlSi3O8–CaAl2Si2O8) have been presented for aliquots along (001) and (010) crystallographic orientations. There are four main emission bands that are considered to arise from complexes of intrinsic defects linked in larger complexes with impurities such as Na+, Mn2+ or Fe3+ ions. The consequence of their association is to produce different luminescence efficiencies that produce wavelength sensitive TL curves. Radioluminescence data at low temperature for albites is distorted by contributions from the TL sites, even when the RL is run in a cooling cycle. This indicates the potential for a far more general problem for analysis of low temperature RL in insulating materials.

Radiation Measurements, 2011

Feldspar as an archaeological and geological natural material for dating and retrospective dosime... more Feldspar as an archaeological and geological natural material for dating and retrospective dosimetry is receiving more and more attention because of its useful luminescence properties. In this study, the 25–280 K thermoluminescence (TL) and radioluminescence (RL) spectra in albite, which is a component of the two main feldspar series, the alkali feldspar (Na, K)AlSi3O8 and the plagioclases (NaAlSi3O8–CaAl2Si2O8) have been presented for aliquots along (001) and (010) crystallographic orientations. There are four main emission bands that are considered to arise from complexes of intrinsic defects linked in larger complexes with impurities such as Na+, Mn2+ or Fe3+ ions. The consequence of their association is to produce different luminescence efficiencies that produce wavelength sensitive TL curves. Radioluminescence data at low temperature for albites is distorted by contributions from the TL sites, even when the RL is run in a cooling cycle. This indicates the potential for a far more general problem for analysis of low temperature RL in insulating materials.

Radiation Measurements, 2006

In this study concentrations of 210 Po and 210 Pb radionuclides in soils and vegetables collected... more In this study concentrations of 210 Po and 210 Pb radionuclides in soils and vegetables collected from both cultivated and uncultivated agricultural lands of the Kucuk Menderes basin were determined. 210 Po and 210 Pb 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 210 Po and 210 Pb, respectively. In the bulk soil cores sampled from phosphate fertilizer-applied agricultural lands, the ranges for activity concentrations of 210 Po and 210 Pb are 30.10-47.15 Bq kg −1 and 31.27-61.53 Bq kg −1 , respectively. 210 Po and 210 Pb activity concentrations in soil cores collected from uncultivated soils were also determined for comparison.

Radiation Measurements, 2006

In this study concentrations of 210 Po and 210 Pb radionuclides in soils and vegetables collected... more In this study concentrations of 210 Po and 210 Pb radionuclides in soils and vegetables collected from both cultivated and uncultivated agricultural lands of the Kucuk Menderes basin were determined. 210 Po and 210 Pb 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 210 Po and 210 Pb, respectively. In the bulk soil cores sampled from phosphate fertilizer-applied agricultural lands, the ranges for activity concentrations of 210 Po and 210 Pb are 30.10-47.15 Bq kg −1 and 31.27-61.53 Bq kg −1 , respectively. 210 Po and 210 Pb activity concentrations in soil cores collected from uncultivated soils were also determined for comparison.

Radiation Effects and Defects in Solids, 2001

Luminescence from rare earth ions provides spectral signatures that identify the type of site. Su... more 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

Radiation Effects and Defects in Solids, 2001

Luminescence from rare earth ions provides spectral signatures that identify the type of site. Su... more 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

Physica B: Condensed Matter, 2005

Copper nanoparticles have been formed in a zinc oxide (ZnO) substrate by Cu implantation at 160 k... more 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. r

Mineralogical Magazine, 1999

Cathodoluminescence (CL) provides a sensitive analytical probe of the near-surface region of insu... more 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 ftmction of their depth beneath the surface. Correlation of the CL data with those from Mrssbauer, 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.

Physica B: Condensed Matter, 2010

Fire opal (SiO 2 Á nH 2 O) and diaspore [Al(OH)O] are two different precious and rare mineral spe... more Fire opal (SiO 2 Á nH 2 O) 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 (H 2 O) and hydroxyl (OH) group) and transformation of the base building components and/or inclusion minerals.

Physica B: Condensed Matter, 2010

Fire opal (SiO 2 Á nH 2 O) and diaspore [Al(OH)O] are two different precious and rare mineral spe... more Fire opal (SiO 2 Á nH 2 O) 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 (H 2 O) and hydroxyl (OH) group) and transformation of the base building components and/or inclusion minerals.

Radiation Measurements, 2007

The aim of this study is to determine the enhancement in natural radioactivity level of soils due... more 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.

Radiation Measurements, 2007

The aim of this study is to determine the enhancement in natural radioactivity level of soils due... more 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.

Physica B: Condensed Matter, 2010

ABSTRACT In this study, thermal properties and thermal decompositions of dehydration behaviour of... more ABSTRACT 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 Sarıcakaya-Eskişehir 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 Å. During heating from the room temperature to 300 °C, the thermoluminescence pattern of the blue chalcedony shows a characteristic peak at 210 °C. This peak may be due to unusually high traces of the impurities S, Th, Tl, U, and W. During heating from the room temperature to 1400 °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 °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 °C. In addition, there is one distinctive sharp exotherm and one weaker exotherm at 1270 °C.

Physica B: Condensed Matter, 2010

ABSTRACT In this study, thermal properties and thermal decompositions of dehydration behaviour of... more ABSTRACT 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 Sarıcakaya-Eskişehir 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 Å. During heating from the room temperature to 300 °C, the thermoluminescence pattern of the blue chalcedony shows a characteristic peak at 210 °C. This peak may be due to unusually high traces of the impurities S, Th, Tl, U, and W. During heating from the room temperature to 1400 °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 °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 °C. In addition, there is one distinctive sharp exotherm and one weaker exotherm at 1270 °C.

Luminescence, 2014

Thermally stimulated luminescence glow curves of CaB4 O7 :Dy samples after β-irradiation showed g... more Thermally stimulated luminescence glow curves of CaB4 O7 :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 computerized glow curve deconvolution (CGCD) analysis of the complex peak of the dosimetric material of interest. The kinetic parameters, namely activation energy (E) and frequency factor (s), associated with the main glow peak of CaB4 O7 :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.

Luminescence, 2014

Thermally stimulated luminescence glow curves of CaB4 O7 :Dy samples after β-irradiation showed g... more Thermally stimulated luminescence glow curves of CaB4 O7 :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 computerized glow curve deconvolution (CGCD) analysis of the complex peak of the dosimetric material of interest. The kinetic parameters, namely activation energy (E) and frequency factor (s), associated with the main glow peak of CaB4 O7 :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.

Radiation Measurements, 2011

Feldspar as an archaeological and geological natural material for dating and retrospective dosime... more Feldspar as an archaeological and geological natural material for dating and retrospective dosimetry is receiving more and more attention because of its useful luminescence properties. In this study, the 25–280 K thermoluminescence (TL) and radioluminescence (RL) spectra in albite, which is a component of the two main feldspar series, the alkali feldspar (Na, K)AlSi3O8 and the plagioclases (NaAlSi3O8–CaAl2Si2O8) have been presented for aliquots along (001) and (010) crystallographic orientations. There are four main emission bands that are considered to arise from complexes of intrinsic defects linked in larger complexes with impurities such as Na+, Mn2+ or Fe3+ ions. The consequence of their association is to produce different luminescence efficiencies that produce wavelength sensitive TL curves. Radioluminescence data at low temperature for albites is distorted by contributions from the TL sites, even when the RL is run in a cooling cycle. This indicates the potential for a far more general problem for analysis of low temperature RL in insulating materials.

Radiation Measurements, 2011

Feldspar as an archaeological and geological natural material for dating and retrospective dosime... more Feldspar as an archaeological and geological natural material for dating and retrospective dosimetry is receiving more and more attention because of its useful luminescence properties. In this study, the 25–280 K thermoluminescence (TL) and radioluminescence (RL) spectra in albite, which is a component of the two main feldspar series, the alkali feldspar (Na, K)AlSi3O8 and the plagioclases (NaAlSi3O8–CaAl2Si2O8) have been presented for aliquots along (001) and (010) crystallographic orientations. There are four main emission bands that are considered to arise from complexes of intrinsic defects linked in larger complexes with impurities such as Na+, Mn2+ or Fe3+ ions. The consequence of their association is to produce different luminescence efficiencies that produce wavelength sensitive TL curves. Radioluminescence data at low temperature for albites is distorted by contributions from the TL sites, even when the RL is run in a cooling cycle. This indicates the potential for a far more general problem for analysis of low temperature RL in insulating materials.

Radiation Measurements, 2006

In this study concentrations of 210 Po and 210 Pb radionuclides in soils and vegetables collected... more In this study concentrations of 210 Po and 210 Pb radionuclides in soils and vegetables collected from both cultivated and uncultivated agricultural lands of the Kucuk Menderes basin were determined. 210 Po and 210 Pb 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 210 Po and 210 Pb, respectively. In the bulk soil cores sampled from phosphate fertilizer-applied agricultural lands, the ranges for activity concentrations of 210 Po and 210 Pb are 30.10-47.15 Bq kg −1 and 31.27-61.53 Bq kg −1 , respectively. 210 Po and 210 Pb activity concentrations in soil cores collected from uncultivated soils were also determined for comparison.

Radiation Measurements, 2006

In this study concentrations of 210 Po and 210 Pb radionuclides in soils and vegetables collected... more In this study concentrations of 210 Po and 210 Pb radionuclides in soils and vegetables collected from both cultivated and uncultivated agricultural lands of the Kucuk Menderes basin were determined. 210 Po and 210 Pb 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 210 Po and 210 Pb, respectively. In the bulk soil cores sampled from phosphate fertilizer-applied agricultural lands, the ranges for activity concentrations of 210 Po and 210 Pb are 30.10-47.15 Bq kg −1 and 31.27-61.53 Bq kg −1 , respectively. 210 Po and 210 Pb activity concentrations in soil cores collected from uncultivated soils were also determined for comparison.

Radiation Effects and Defects in Solids, 2001

Luminescence from rare earth ions provides spectral signatures that identify the type of site. Su... more 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

Radiation Effects and Defects in Solids, 2001

Luminescence from rare earth ions provides spectral signatures that identify the type of site. Su... more 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

Physica B: Condensed Matter, 2005

Copper nanoparticles have been formed in a zinc oxide (ZnO) substrate by Cu implantation at 160 k... more 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. r

Mineralogical Magazine, 1999

Cathodoluminescence (CL) provides a sensitive analytical probe of the near-surface region of insu... more 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 ftmction of their depth beneath the surface. Correlation of the CL data with those from Mrssbauer, 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.