Method and apparatus for reducing solvent luminescence background emissions

Energy Technology Data Exchange (ETDEWEB)

Affleck, Rhett L. (Los Alamos, NM); Ambrose, W. Patrick (Los Alamos, NM); Demas, James N. (Charlottesville, VA); Goodwin, Peter M. (Jemez Springs, NM); Johnson, Mitchell E. (Pittsburgh, PA); Keller, Richard A. (Los Alamos, NM); Petty, Jeffrey T. (Los Alamos, NM); Schecker, Jay A. (Santa Fe, NM); Wu, Ming (Los Alamos, NM)

1998-01-01

The detectability of luminescent molecules in solution is enhanced by reducing the background luminescence due to impurity species also present in the solution. A light source that illuminates the solution acts to photolyze the impurities so that the impurities do not luminesce in the fluorescence band of the molecule of interest. Molecules of interest may be carried through the photolysis region in the solution or may be introduced into the solution after the photolysis region.

Luminescence variations in europium-doped silicon-substituted hydroxyapatite nanobiophosphor via three different methods

Energy Technology Data Exchange (ETDEWEB)

Thang, Cao Xuan; Pham, Vuong-Hung, E-mail: vuong.phamhung@hust.edu.vn

2015-07-15

Highlights: • Europium doped silicon-substituted hydroxyapatite was synthesized by wet chemical synthesis method. • Morphology of nanoparticles depended on the synthesized method. • Photoluminescence intensity of the sample increases with the increasing of Si substitutions, Eu dopants and thermal annealing. - Abstract: This paper reports the first attempt for the synthesis of europium-doped Si-substituted hydroxyapatite (HA) nanostructure to achieve strong and stable luminescence of nanobiophosphor, particularly, by addition of different Eu dopants, Si substitutions, and application of optimum annealing temperatures of up to 1000 °C. The nanobiophosphor was synthesized by the coprecipitation, microwave, and hydrothermal methods. The nanoparticles demonstrated a nanowire to a spindle-like morphology, which was dependent on the method of synthesis. The photoluminescence (PL) intensity of the sample increases with the increase in Si substitutions and Eu dopants. The luminescent nanoparticles also showed the typical luminescence of Eu{sup 3+} centered at 610 nm, which was more efficient for the annealed Eu-doped Si-HA nanoparticles than for the as-synthesized nanoparticles. Among the different synthesis methods, the hydrothermal method reveals the best light emission represented by high PL intensity and narrow PL spectra. These results suggest the potential application of Eu-doped Si-HA in stable and biocompatible nanophosphors for light emission and nanomedicine.

Time-resolved luminescence screening method for enrofloxacin in beef serum

Science.gov (United States)

Enrofloxacin is one of only two fluoroquinolone antibiotics approved for use in cattle in the U.S. Microbial screening methods currently used in the U.S. for monitoring veterinary drug residues are not sensitive or selective for fluoroquinolones. In this work, a luminescence-based screening assay ...

[Digital luminescence radiography. A new method of study in thoracic diagnosis at the intensive care unit].

Science.gov (United States)

Witte, G; Pothmann, W; Bause, H; Nicolas, V; Schulte am Esch, J; Bücheler, E

1989-02-01

The digital luminescence-radiography (DLR) technique relies on a complete digitalization of the X-ray image. Luminescence crystals on the imaging plate serve as an energy reservoir following their exposure to ionized radiation from any conventional X-ray source. A Helium-Neon laser stimulates the electrons in their high energy bands and therefore will be dropped back emitting luminescence. This luminescence is digitized by the DLR-System thus delivering a complete digital image to the image processor for subsequent processing and evaluation. The processed digital image is then recorded on a conventional film or a monitor screen. More than 3000 chest examinations using DLR have been performed on intensive care unit (ICU) patients at the University Hospital Eppendorf following the first eleven months since the clinical introduction of this new technique. The positive aspects of DLR such as high-contrast resolution and optimal reproducibility were clinically evaluated under ICU conditions. It was shown that DLR greatly improves the quality of the chest X-rays of all ICU patients and offers the following advantages: reproducibility, lateral chest projection, no insufficient exposure, reduction of exposure dose, electronical post-processing and storage, quality preserving digital storage and copying.

Basic study on electrically stimulated luminescence (ESL) as a dosimetry and dating method

International Nuclear Information System (INIS)

Sato, H.; Yamanaka, C.; Ikeya, M.

2003-01-01

Electrically stimulated luminescence (ESL) of calcium carbonate has been studied for application as dosimetry and dating. A powdered calcium carbonate was sandwiched by electrodes, which supplied electric field. Luminescence and surface current through a powdered sample were measured using a photomultiplier and a digital multimeter, respectively. A linear dependence of ESL on the absorbed dose by γ-rays was found when the applied voltage was below the breakdown threshold. Reciprocal electric charges through the sample had also linear relation with the absorbed dose. We propose that the luminescence and electric charge under intense electric field in calcium carbonate become new methods for dosimetry and dating on the basis of the surface defects of the calcium carbonate grains produced by the irradiation of γ-rays

Luminescent beam stop

Energy Technology Data Exchange (ETDEWEB)

Bryant, Diane; Morton, Simon A.

2017-10-25

This disclosure provides systems, methods, and apparatus related to beam stops. In one aspect, a device comprises a luminescent material, a beam stop plate, and an optical fiber. The luminescent material is a parallelepiped having a first side and a second side that are squares and having a third side that is a rectangle or a square. The first side and the second side are perpendicular to the third side. The beam stop plate is attached to the first side of the luminescent material. The optical fiber has a first end and a second end, with the first end of the optical fiber attached to the third side of the luminescent material.

AgesGalore-A software program for evaluating spatially resolved luminescence data

International Nuclear Information System (INIS)

Greilich, S.; Harney, H.-L.; Woda, C.; Wagner, G.A.

2006-01-01

Low-light luminescence is usually recorded by photomultiplier tubes (PMTs) yielding integrated photon-number data. Highly sensitive CCD (charged coupled device) detectors allow for the spatially resolved recording of luminescence. The resulting two-dimensional images require suitable software for data processing. We present a recently developed software program specially designed for equivalent-dose evaluation in the framework of optically stimulated luminescence (OSL) dating. The software is capable of appropriate CCD data handling, parameter estimation using a Bayesian approach, and the pixel-wise fitting of functions for time and dose dependencies to the luminescence signal. The results of the fitting procedure and the equivalent-dose evaluation can be presented and analyzed both as spatial and as frequency distributions

Luminescence detection of shellfish

International Nuclear Information System (INIS)

Sanderson, D.C.W.; Carmichael, L.A.; Spencer, J.Q.; Naylor, J.D.

1996-01-01

The Scottish Universities Research and Reactor Centre (SURRC) has been active in the development and application of luminescence techniques in the detection of irradiated foods, in support of UK legislation. Thermoluminescence (TL), photostimulated luminescence (PSL) and photo-transfer luminescence (PTTL) are radiation-specific phenomena which arise due to energy stored by trapped charge carriers following irradiation. The energy released following stimulation is accompanied by detectable luminescence. The TL method involves preparation of pure silicate extracts from the sample and subsequent TL analysis, whereas PSL uses stimulation by electromagnetic radiation (visible, or near visible wavelengths) thus avoiding heating the sample. (author)

Luminescence as a new detection method for non-relativistic highly ionizing particles in water/ice neutrino telescopes

Energy Technology Data Exchange (ETDEWEB)

Pollmann, Anna [Bergische Universitaet Wuppertal (Germany); Collaboration: IceCube-Collaboration

2016-07-01

Cosmic ray detectors use air as a radiator for luminescence. In water and ice detectors Cherenkov light is the dominant light producing mechanism when the particle velocity exceeds the Cherenkov threshold, approximately three quarters of the speed of light. Luminescence is produced by highly ionizing particles passing through matter due to the excitation of the surrounding atoms. The observables of luminescence, such as the wavelength spectrum and decay times, are highly dependent on the properties of the medium. Therefore, the results of measurements, in which luminescence was produced by particles passing through water or ice, vary by two orders of magnitude in intensity. It is shown that, even for the most conservative intensity value, luminescence can be used as a detection method for highly ionizing particles with velocities below the Cherenkov threshold. These could be magnetic monopoles or other massive and highly penetrating exotic particles. In the most optimistic case, luminescence contributes even to the light output of standard model particles.

Discuss on luminescence dose data analysis technology

International Nuclear Information System (INIS)

Ma Xinhua; Xiao Wuyun; Ai Xianyun; Shi Zhilan; Liu Ying

2009-01-01

This article describes the development of luminescence dose data measurement and processing technology. General design planning of luminescence dose data measurement and processing technology is put forward with the diverse demands. The emphasis is focused on dose data processing method, luminescence curve analysis method, using of network, mechanics of communication among computers, data base management system of individual dose in this paper. The main methods and skills used in this technology as well as their advantages are also discussed. And it offers general design references for development luminescence dose data processing software. (authors)

Resonance-shifting luminescent solar concentrators

Energy Technology Data Exchange (ETDEWEB)

Giebink, Noel Christopher; Wiederrecht, Gary P.; Wasielewski, Michael R.

2018-01-23

An optical system and method to overcome luminescent solar concentrator inefficiencies by resonance-shifting, in which sharply directed emission from a bi-layer cavity into a glass substrate returns to interact with the cavity off-resonance at each subsequent reflection, significantly reducing reabsorption loss en route to the edges. In one embodiment, the system comprises a luminescent solar concentrator comprising a transparent substrate, a luminescent film having a variable thickness; and a low refractive index layer disposed between the transparent substrate and the luminescent film.

Determination of molecular structures of aromatic hydrocarbons of crystal fractions of Noriysk crude by a series of luminescent-spectral methods

Energy Technology Data Exchange (ETDEWEB)

Ogloblina, A.I.; Alekseyeva, T.A.; Barabadze, Sh.Sh.; Melikadze, L.D.; Teplitskaya, T.A.

1979-01-01

The structure of crystalline aromatic hydrocarbons isolated from the high boiling fraction (540-560 degrees) of Noriysk crude was studied using methods of luminescent-spectral analysis. The individual composition of the crystalline aromatic hydrocarbons was analyzed by a combination of fine structure luminescent spectroscopy and spectrofluorimetric methods in frozen matrices using spectra of fluorescence, phosphorescence and excitation of luminescence. The composite method used at 77 K is very effective and allows detailed characteristics of the molar-group composition of complex mixtures of petroleum aromatic hydrocarbons to the point of identification of individual components.

Seismic Moment and Recurrence using Luminescence Dating Techniques: Characterizing brittle fault zone materials suitable for luminescence dating

Science.gov (United States)

Tsakalos, E.; Lin, A.; Bassiakos, Y.; Kazantzaki, M.; Filippaki, E.

2017-12-01

During a seismic-geodynamic process, frictional heating and pressure are generated on sediments fragments resulting in deformation and alteration of minerals contained in them. The luminescence signal enclosed in minerals crystal lattice can be affected and even zeroed during such an event. This has been breakthrough in geochronological studies as it could be utilized as a chronometer for the previous seismic activity of a tectonically active area. Although the employment of luminescence dating has in some cases been successfully described, a comprehensive study outlining and defining protocols for routine luminescence dating applied to neotectonic studies has not been forthcoming. This study is the experimental investigation, recording and parameterization of the effects of tectonic phenomena on minerals luminescence signal and the development of detailed protocols for the standardization of the luminescence methodology for directly dating deformed geological formations, so that the long-term temporal behaviour of seismically active faults could be reasonably understood and modeled. This will be achieved by: a) identifying and proposing brittle fault zone materials suitable for luminescence dating using petrological, mineralogical and chemical analyses and b) investigating the "zeroing" potential of the luminescence signal of minerals contained in fault zone materials by employing experimental simulations of tectonic processes in the laboratory, combined with luminescence measurements on samples collected from real fault zones. For this to be achieved, a number of samples collected from four faults of four different geographical regions will be used. This preliminary-first step of the study presents the microstructural, and mineralogical analyses for the characterization of brittle fault zone materials that contain suitable minerals for luminescence dating (e.g., quartz and feldspar). The results showed that the collected samples are seismically deformed fault

Determination of uranium in sea and ocean waters by a luminescence method with laser excitation

International Nuclear Information System (INIS)

Preobrazhenskaya, E.B.; Gvgel, E.S.; Stepanov, A.V.

1986-01-01

This paper shows that it is possible to determine uranium insea and ocean waters by a luminescence method with laser excitation. Ocean waters with a low content of luminescent ingredients are analyzed directly by freezing at 77 K to eliminate the quenching effect of the chloride ion. The more polluted waters of inland seas are preferably analyzed at T = 293 K in 1 M H 3 PO 4 after the removal of chloride ions by distillation from a sample containing HNO 3 . The background effect is removed by time selection of the luminescent emission of the uranyl ion. Uranium contents were determined for water from the northwest Atlantic and the North and Baltic Seas

Ceramic luminescent radiographic materials for medicine and tool construction

International Nuclear Information System (INIS)

Winnacker, A.

1991-01-01

X-ray recording luminescent materials form the basis of a new concept for X ray imaging. Essential advantages as compared to the conventional film systems are the digitalisation of the X ray as well as the high dynamics of registration. Modern methods of image processing and video recording can be applied. Advantages also show where a very extensive video material must be filed. Compared to the films used up to now, one expects higher sensitivity, higher homogeneity and higher spatial resolution of pictures taken with ceramic films. (BaFBr:Eu, RbJ:Tl). (orig.) [de

Luminescent Eosin Y–SiO2 hybrid nano and microrods prepared by sol–gel template method

International Nuclear Information System (INIS)

Secu, M.; Secu, C.E.; Sima, M.; Negrea, R.F.; Bartha, C.; Dinescu, M.; Damian, V.

2013-01-01

Sol–gel chemistry within the pores of a polycarbonate template membrane was used for the preparation of Eosin Y–SiO 2 hybrid nano- and microrods, using tetraethylorthosilicate [TEOS, Si(OC 2 H 5 ) 4 ] as the precursor in the presence of trifluoroacetic acid (TFA) catalyst. The ethanolic solution of Eosin-Y was added to the silica sol to trap dye molecules inside the SiO 2 gel network during the gelation. Structural and morphological characterization using scanning electron microscopy (SEM) and luminescence microscopy have shown the formation of rods with 200 nm and 1.2 μm diameter and about 30 μm length, exhibiting luminescence properties. Spectroscopic characterization has shown that the luminescence is due to Eosin-Y molecule in the xerogel porous network, surrounded by a solvation shell given mainly by the water. -- Highlights: • Sol–gel template method was used to prepare Eosin Y–SiO 2 hybrid rods-type structures. • Morphological characterization has shown nano- and microrods with luminescent properties. • Luminescence is due to Eosin-Y molecule surrounded by a solvation shell given by water

Highly sensitive luminescence method of scandium determination in the products of metallurgical reprocessing

International Nuclear Information System (INIS)

Matveets, M.A.; Akhmetova, S.D.

1988-01-01

Highly sensitive reaction of scandium with 1,10-phenanthroline and eosin is used for the development of luminescence method of its determination in metallurgical products. The effect of interfering elements is eliminated by scandium extraction with monocarboxylic acids. The method permits to determine scandium content from 5 x 10 -5 % (Sr 0.15 - 0.25)

Luminescence nanothermometry

Science.gov (United States)

Jaque, Daniel; Vetrone, Fiorenzo

2012-07-01

The current status of luminescence nanothermometry is reviewed in detail. Based on the main parameters of luminescence including intensity, bandwidth, bandshape, polarization, spectral shift and lifetime, we initially describe and compare the different classes of luminescence nanothermometry. Subsequently, the various luminescent materials used in each case are discussed and the mechanisms at the root of the luminescence thermal sensitivity are described. The most important results obtained in each case are summarized and the advantages and disadvantages of these approaches are discussed.The current status of luminescence nanothermometry is reviewed in detail. Based on the main parameters of luminescence including intensity, bandwidth, bandshape, polarization, spectral shift and lifetime, we initially describe and compare the different classes of luminescence nanothermometry. Subsequently, the various luminescent materials used in each case are discussed and the mechanisms at the root of the luminescence thermal sensitivity are described. The most important results obtained in each case are summarized and the advantages and disadvantages of these approaches are discussed. This work was supported by the Universidad Autónoma de Madrid and Comunidad Autónoma de Madrid (Project S2009/MAT-1756), by the Spanish Ministerio de Educacion y Ciencia (MAT2010-16161) and by Caja Madrid Foundation.

Cone Beam X-ray Luminescence Computed Tomography Based on Bayesian Method.

Science.gov (United States)

Zhang, Guanglei; Liu, Fei; Liu, Jie; Luo, Jianwen; Xie, Yaoqin; Bai, Jing; Xing, Lei

2017-01-01

X-ray luminescence computed tomography (XLCT), which aims to achieve molecular and functional imaging by X-rays, has recently been proposed as a new imaging modality. Combining the principles of X-ray excitation of luminescence-based probes and optical signal detection, XLCT naturally fuses functional and anatomical images and provides complementary information for a wide range of applications in biomedical research. In order to improve the data acquisition efficiency of previously developed narrow-beam XLCT, a cone beam XLCT (CB-XLCT) mode is adopted here to take advantage of the useful geometric features of cone beam excitation. Practically, a major hurdle in using cone beam X-ray for XLCT is that the inverse problem here is seriously ill-conditioned, hindering us to achieve good image quality. In this paper, we propose a novel Bayesian method to tackle the bottleneck in CB-XLCT reconstruction. The method utilizes a local regularization strategy based on Gaussian Markov random field to mitigate the ill-conditioness of CB-XLCT. An alternating optimization scheme is then used to automatically calculate all the unknown hyperparameters while an iterative coordinate descent algorithm is adopted to reconstruct the image with a voxel-based closed-form solution. Results of numerical simulations and mouse experiments show that the self-adaptive Bayesian method significantly improves the CB-XLCT image quality as compared with conventional methods.

Search for the dose-sensitive optically stimulated luminescence response in natural carbonates

International Nuclear Information System (INIS)

Jaek, Ivar; Huett, Galina; Rammo, Ilmar; Vasilchenko, Valeri

2001-01-01

Carbonates of different origin, such as Iceland spar, calcites, and mollusc shells, used as electron spin resonance and thermoluminescence paleodosimeters, were studied in order to determine their suitability for optically stimulated luminescence dating. The stimulation/excitation spectra of the afterglow of the samples were recorded in the wavelength range of 250-1100 nm. The results of the study show that these spectra present either excitation spectra of Mn 2+ ion fluorescence (samples of calcites and Iceland spar, red emission recorded) or the excitation spectra of primary phosphorescence (samples of carbonates, including molluscs shells; short-wave emission bands recorded). The recorded stimulation spectra revealed no spectral bands sensitive to stimulation by ionizing radiation, which would disappear as a result of heating and could thus be related to deep traps in carbonates, needed dating. The cause of this situation which is unusual in luminescent crystals, including luminescence (paleo)dosimeters, and the ways of overcoming the difficulties in optical dating of natural carbonates are discussed. (author)

Modern luminescence spectroscopy of minerals and materials

CERN Document Server

Gaft, Michael; Panczer, Gerard

2005-01-01

Luminescence Spectroscopy of Minerals and Materials presents an overview of the general concepts in luminescence spectroscopy as well as experimental methods and their interpretation. Special emphasis is laid on the fluorescence lifetime and the determination of time-resolved spectra. This method enables the exposure of new luminescence in minerals previously hidden by more intensive centers. Specialists in the fields of solid state physics, chemistry and spectroscopy will find a wealth of new information in this unique book.

Synthesis of yttrium silicate luminescent materials by sol-gel method

International Nuclear Information System (INIS)

Arkhipov, D.V.; Vasina, O.Yu.; Popovich, N.V.; Galaktionov, S.S.; Soshchin, N.P.

1996-01-01

Several yttrium-silicate composition with Y 2 O 3 content within 44-56% have been synthesized. it is ascertained that employment of sol-gel technique permits preparation of luminescent materials on yttrium silicate basis, which compare favourably with bath-produced specimens. The influence of phase composition of sol-gel phosphors on basic performance indices: intensity and luminescence spectrum, has been analyzed

Luminescence Properties of Surface Radiation-Induced Defects in Lithium Fluoride

Science.gov (United States)

Voitovich, A. P.; Kalinov, V. S.; Martynovich, E. F.; Novikov, A. N.; Runets, L. P.; Stupak, A. P.

2013-11-01

Luminescence and luminescence excitation spectra are recorded for surface radiation-induced defects in lithium fluoride at temperatures of 77 and 293 K. The presence of three bands with relatively small intensity differences is a distinctive feature of the excitation spectrum. These bands are found to belong to the same type of defects. The positions of the peaks and the widths of the absorption and luminescence bands for these defects are determined. The luminescence decay time is measured. All the measured characteristics of these surface defects differ from those of previously known defects induced by radiation in the bulk of the crystals. It is found that the luminescence of surface defects in an ensemble of nanocrystals with different orientations is not polarized. The number of anion vacancies in the surface defects is estimated using the polarization measurements. It is shown that radiative scattering distorts the intensity ratios of the luminescence excitation bands located in different spectral regions.

Luminescence enhancement of uranyl ion by benzoic acid in acetonitrile

International Nuclear Information System (INIS)

Satendra Kumar; Maji, S.; Joseph, M.; Sankaran, K.

2014-01-01

Uranyl ion is known for its characteristic green luminescence and therefore luminescence spectroscopy is a suitable technique for characterizing different uranyl species. In aqueous medium, luminescence of uranyl ion is generally weak due to its quenching by water molecules and therefore in order to enhance the luminescence of uranyl ion in aqueous medium, luminescence enhancing reagents such as H 3 PO 4 , H 2 SO 4 , HCIO 4 have been widely used. The other method to enhance the uranyl luminescence is by ligand sensitized luminescence, a method well established for lanthanides. In this work, luminescence of uranyl ion is found to be enhanced by benzoic acid in acetonitrile medium. In aqueous medium benzoic acid does not enhance the uranyl luminescence although it forms 1:1 and 1:2 complexes with uranyl ion. Luminescence spectra of uranyl benzoate revealed that enhancement is due to sensitization of uranyl luminescence by benzoate ions. UV-Vis spectroscopy has been utilized to characterize the specie formed in the in acetonitrile medium. UV-Vis spectroscopy along with luminescence spectra revealed that the specie to be tribenzoate complex of uranyl (UO 2 (C 6 H 5 COO) 3 ) - having D 3 h symmetry. (author)

Luminescent Eosin Y–SiO{sub 2} hybrid nano and microrods prepared by sol–gel template method

Energy Technology Data Exchange (ETDEWEB)

Secu, M., E-mail: msecu@infim.ro [National Institute for Materials Physics, P.O. Box MG-7, Bucharest–Magurele, 077125 (Romania); Secu, C.E.; Sima, M.; Negrea, R.F.; Bartha, C. [National Institute for Materials Physics, P.O. Box MG-7, Bucharest–Magurele, 077125 (Romania); Dinescu, M.; Damian, V. [National Institute for Laser, Plasma and Radiation, P.O. Box MG-36, Bucharest–Magurele 077125 (Romania)

2013-11-15

Sol–gel chemistry within the pores of a polycarbonate template membrane was used for the preparation of Eosin Y–SiO{sub 2} hybrid nano- and microrods, using tetraethylorthosilicate [TEOS, Si(OC{sub 2}H{sub 5}){sub 4}] as the precursor in the presence of trifluoroacetic acid (TFA) catalyst. The ethanolic solution of Eosin-Y was added to the silica sol to trap dye molecules inside the SiO{sub 2} gel network during the gelation. Structural and morphological characterization using scanning electron microscopy (SEM) and luminescence microscopy have shown the formation of rods with 200 nm and 1.2 μm diameter and about 30 μm length, exhibiting luminescence properties. Spectroscopic characterization has shown that the luminescence is due to Eosin-Y molecule in the xerogel porous network, surrounded by a solvation shell given mainly by the water. -- Highlights: • Sol–gel template method was used to prepare Eosin Y–SiO{sub 2} hybrid rods-type structures. • Morphological characterization has shown nano- and microrods with luminescent properties. • Luminescence is due to Eosin-Y molecule surrounded by a solvation shell given by water.

Linear least-squares method for global luminescent oil film skin friction field analysis

Science.gov (United States)

Lee, Taekjin; Nonomura, Taku; Asai, Keisuke; Liu, Tianshu

2018-06-01

A data analysis method based on the linear least-squares (LLS) method was developed for the extraction of high-resolution skin friction fields from global luminescent oil film (GLOF) visualization images of a surface in an aerodynamic flow. In this method, the oil film thickness distribution and its spatiotemporal development are measured by detecting the luminescence intensity of the thin oil film. From the resulting set of GLOF images, the thin oil film equation is solved to obtain an ensemble-averaged (steady) skin friction field as an inverse problem. In this paper, the formulation of a discrete linear system of equations for the LLS method is described, and an error analysis is given to identify the main error sources and the relevant parameters. Simulations were conducted to evaluate the accuracy of the LLS method and the effects of the image patterns, image noise, and sample numbers on the results in comparison with the previous snapshot-solution-averaging (SSA) method. An experimental case is shown to enable the comparison of the results obtained using conventional oil flow visualization and those obtained using both the LLS and SSA methods. The overall results show that the LLS method is more reliable than the SSA method and the LLS method can yield a more detailed skin friction topology in an objective way.

Direct and indirect dating of gypsum occurrences in deserts using luminescence methods

International Nuclear Information System (INIS)

Nagar, Y.C.; Juyal, N.; Singhyi, A.K.; Kocurek, G.; Wadhawan, S.K.

2005-01-01

In the present study we have made an attempt to directly date gypsum or provide indirect age estimate for gypsum formation through dating the associated sediments (quartz) using the luminescence dating technique. In the direct dating of gypsum, we explored the Optically Stimulated Luminescence (OSL) and Thermally Stimulated Luminescence (TL) behaviour of gypsum. The associated sediments (indirect dating) were dated using the traces of quartz extract from gypsum (concentration 0.1% ) and the underlying and overlying quartz sand in playa

Method for the substantial reduction of quenching effects in luminescence spectrometry

Science.gov (United States)

Demas, J.N.; Jones, W.M.; Keller, R.A.

1987-06-26

Method for reducing quenching effects in analytical luminescence measurements. Two embodiments of the present invention are described which relate to a form of time resolution based on the amplitudes and phase shifts of modulated emission signals. In the first embodiment, the measured modulated emission signal is substantially independent of sample quenching at sufficiently high frequencies. In the second embodiment, the modulated amplitude and the phase shift between the emission signal and the excitation source are simultaneously measured. Using either method, the observed modulated amplitude may be reduced to its unquenched value. 3 figs.

Study of Polymeric Luminescent Blend (PC/PMMA) Doped with Europium Complex under Gamma-Iradiation

International Nuclear Information System (INIS)

Parra, D. F.

2006-01-01

Spectroscopic properties of blends formed by bisphenol-A polycarbonate (PC) and poly(methyl methacrylate) (PMMA) doped with europium in organic complex were studied. Polymeric luminescent blends are potential materials for many applications; however, little information has been reported concerning the stability under thermal and radiation conditions. Luminescent films were synthesized from europium thenoyltrifluoroacetonate at different concentrations doped in PC/PMMA blends. Films produced of the luminescent polymer blend were irradiated in a 60 C o source. Their luminescent properties, in the solid state, as well as, the thermal oxidative resistance after gamma irradiation was investigated. These systems were characterized by elemental analysis, thermogravimetry (TGA), differential scanning calorimetry (DSC) and infrared spectroscopy (FTIR). Based on TGA data, the thermal stability of PC/PMMA:(tta)3 system is higher than the polymer blend. The DSC results indicated that those new systems are chemically stables. The emission spectra of the Eu 3 +-tta complex doped in the PC/PMMA recorded at 298 and 77 K exhibited the characteristic bands arising from the 5 D 0 →7 F J transitions (J = 0-6). The luminescence intensity decreases with increasing of precursor concentration in the doped polymer obtained by chemical reaction. This result is different from that of samples obtained by physical method in melting doping. The blend was irradiated under ionizing radiation of 60 C o source. After irradiation of the luminescent films the physical properties of luminescence, thermal and oxidative stability were evaluated.(Fapesp and Cnpq financial support)

Luminescence of Y2O2S-Eu3+ and Ln2O2S-Tb3+ films grown by the method of photostimulated epitaxy

International Nuclear Information System (INIS)

Maksimovskij, S.N.; Sidorov, P.P.; Sluch, M.I.

1990-01-01

Study of luminescence of Y 2 O 2 S-Eu 3+ (1) and La 2 O 2 S-Tb 3+ (2) films, grown from vapor phase by photostimulated epitaxy method is carried out. Spectroscopic analysis data showed that films(1) spectra contain narrow lines, relating to C 3V symmetry centre, and wider lines, relating to C S symmetry centre. Films(2) possess intensive luminescence in green spectral region, but luminescence lines are wider due to higher number of defects. As to production of film luminescent screens the method is shown to be promising

A Terbium Sensitized Luminescence Method for the Assay of Flubiprofen in Pharmaceutical Formulations

Directory of Open Access Journals (Sweden)

Salma M.Z. Al-Kindy

2014-12-01

Full Text Available A sensitive time-resolved luminescence method for the determination of flubiprofen (FLP in methanol and in aqueous solution is described. The method is based on the luminescence sensitization of terbium (Tb3+ by the formation of a ternary complex with FLP in the presence of 4,7 diphenyl 1,10 phenanthroline (DPP as co-ligand, and Tween-20 as surfactant. The signal for Tb-FLP-DPP was monitored at λex  = 285 nm and λem  = 552 nm. Optimum conditions for the formation of the complex in an aqueous system were TRIS buffer, pH 8.0, DPP (2.5Å~10−7  M, Tween-20 (0.30% and 4Å~10-5  mol L-1  of Tb3+  which allowed the determination of 20–1000 ng mL-1  of FLP with a limit of detection (LOD of 10 ng mL-1 . The relative standard deviations of the method ranged between 0.6 and 1.4% indicating excellent reproducibility of the method. The proposed method was successfully applied for the assays of FLP in pharmaceutical formulations and spiked tap water samples with average recoveries of 87% – 95%.

Conversion of invisible metal-organic frameworks to luminescent perovskite nanocrystals for confidential information encryption and decryption.

Science.gov (United States)

Zhang, Congyang; Wang, Bo; Li, Wanbin; Huang, Shouqiang; Kong, Long; Li, Zhichun; Li, Liang

2017-10-31

Traditional smart fluorescent materials, which have been attracting increasing interest for security protection, are usually visible under either ambient or UV light, making them adverse to the potential application of confidential information protection. Herein, we report an approach to realize confidential information protection and storage based on the conversion of lead-based metal-organic frameworks (MOFs) to luminescent perovskite nanocrystals (NCs). Owing to the invisible and controlled printable characteristics of lead-based MOFs, confidential information can be recorded and encrypted by MOF patterns, which cannot be read through common decryption methods. Through our conversion strategy, highly luminescent perovskite NCs can be formed quickly and simply by using a halide salt trigger that reacts with the MOF, thus promoting effective information decryption. Finally, through polar solvents impregnation and halide salt conversion, the luminescence of the perovskite NCs can be quenched and recovered, leading to reversible on/off switching of the luminescence signal for multiple information encryption and decryption processes.

Luminescent properties of LuAG:Yb and YAG:Yb single crystalline films grown by Liquid Phase Epitaxy method

International Nuclear Information System (INIS)

Zorenko, Yu; Zorenko, T.; Gorbenko, V.; Voznyak, T.; Popielarski, P.; Batentschuk, M.; Osvet, A.; Brabec, Ch; Kolobanov, V.; Spasky, D.; Fedorov, A.

2016-01-01

In this work, investigation of the spectroscopic parameters of the luminescence of Yb"3"+ ions in single crystalline films of Lu_3Al_5O_1_2 and Y_3Al_5O_1_2 garnets was performed using the synchrotron radiation excitation with the energy in the range of Yb"3"+ charge transitions (CT), exciton range and the onset of interband transitions of these garnets. The basic spectroscopic parameters of the Yb"3"+ CT luminescence in LuAG and YAG hosts were determined and summarized with taking into account the differences in the band gap structure of these garnets. - Highlights: • Single crystalline films of Yb doped LuAG and YAG garnets were grown by LPE method. • Yb"3"+ luminescence of LuAG:Yb and YAG:Yb film were studied using synchrotron radiation. • Basic parameters of Yb"3"+ charge transfer luminescence in LuAG and YAG were determined.

Controlled fabrication of luminescent and magnetic nanocomposites

Science.gov (United States)

Ma, Yingxin; Zhong, Yucheng; Fan, Jing; Huang, Weiren

2018-03-01

Luminescent and magnetic multifunctional nanocomposite is in high demand and widely used in many scales, such as drug delivery, bioseparation, chemical/biosensors, and so on. Although lots of strategies have been successfully developed for the demand of multifunctional nanocomposites, it is not easy to prepare multifunctional nanocomposites by using a simple method, and satisfy all kinds of demands simultaneously. In this work, via a facile and versatile method, luminescent nanocrystals and magnetic nanoparticles were successfully synthesized through self-assembly under vigorous stirring and ultrasonic treatment. These multifunctional nanocomposites are not only water stable but also find wide application such as magnetic separation and concentration with a series of moderate speed, multicolor fluorescence at different emission wavelength, high efficiency of the excitation and emission, and so on. By changing different kinds of luminescent nanocrystals and controlling the amount of luminescent and magnetic nanoparticles, a train of multifunctional nanocomposites was successfully fabricated via a versatile and robust method.

The analysis of time-resolved optically stimulated luminescence: I. Theoretical considerations

International Nuclear Information System (INIS)

Chithambo, M L

2007-01-01

This is the first of two linked papers on the analysis of time-resolved optically stimulated luminescence. This paper focusses on a theoretical basis of analytical methods and on methods for interpretation of time-resolved luminescence spectra and calculation of luminescence throughput. Using a comparative analysis of the principal features of time-resolved luminescence and relevant analogues from steady state optical stimulation, formulae for configuring a measurement system for optimum performance are presented. We also examine the possible use of stretched-exponential functions for analysis of time-resolved optically stimulated luminescence spectra

Luminescence of water or ice as a new detection method for magnetic monopoles

Directory of Open Access Journals (Sweden)

Pollmann Anna Obertacke

2017-01-01

We present analysis techniques to use luminescence in neutrino telescopes and discuss experimental setups to measure the light yield of luminescence for the particular conditions in neutrino detectors.

Luminescence from hydrodynamic cavitation. Method and preliminary analysis

International Nuclear Information System (INIS)

Leighton, T.; Farhat, M.; Field, J.

2001-01-01

This report describes a photon-counting study of the cavitation luminescence produced by flow over a hydrofoil. The object was to obtain quantitative data on the number of photons emitted for various flow conditions and to study the link between the light output and the potential for cavitation damage. The flow experiments were performed in a cavitation tunnel capable of achieving flow velocities of up to ca. 50 m s -1 in the test sections. The experimental hydrofoil was a NACA 009 blade. Parameters varied were the flow velocity, the incident angle of the hydrofoil and the cavitation index. The results show that significant photon counts are recorded when leading edge cavitation takes place and U-shaped vortices (cavities) shed from the main cavity. The photon count increases dramatically as the flow velocity increases or the cavitation index is reduced. Departure from a Poisson distribution in the arrival times of photons at the detector may be related to the way vortices shed from the main cavity. Finally, there is a clear correlation between light output and the conditions which could cause cavitation damage. (author)

Luminescence from hydrodynamic cavitation. Method and preliminary analysis

Energy Technology Data Exchange (ETDEWEB)

Leighton, T.; Farhat, M.; Field, J. [and others

2001-06-01

This report describes a photon-counting study of the cavitation luminescence produced by flow over a hydrofoil. The object was to obtain quantitative data on the number of photons emitted for various flow conditions and to study the link between the light output and the potential for cavitation damage. The flow experiments were performed in a cavitation tunnel capable of achieving flow velocities of up to ca. 50 m s{sup -1} in the test sections. The experimental hydrofoil was a NACA 009 blade. Parameters varied were the flow velocity, the incident angle of the hydrofoil and the cavitation index. The results show that significant photon counts are recorded when leading edge cavitation takes place and U-shaped vortices (cavities) shed from the main cavity. The photon count increases dramatically as the flow velocity increases or the cavitation index is reduced. Departure from a Poisson distribution in the arrival times of photons at the detector may be related to the way vortices shed from the main cavity. Finally, there is a clear correlation between light output and the conditions which could cause cavitation damage. (author)

luminescence properties

Indian Academy of Sciences (India)

1Faculty of Science and Arts, Department of Chemistry, Bozok University, Yozgat 66900, Turkey. 2Faculty of Science, Department of Chemistry, Erciyes ... synthesized by the conventional solid-state reaction method, their crystal structures and luminescence properties were investigated. X-ray diffraction patterns (XRD) ...

Reflection measurements for luminescent powders

Science.gov (United States)

Kroon, R. E.

2018-04-01

Luminescent materials are useful in applications varying from lighting and display technologies to document security features and medical research, amongst many others. Measurement of the excitation range is an important consideration, and absorption bands are often determined from a decrease in the measured diffuse reflectance of the material using a ultraviolet-visible (UV-vis) spectrophotometer with an integrating sphere. Such a system may provide questionable results when used to measure the reflectance of a luminescence material, which is demonstrated for a Tb doped silica phosphor, because the system cannot differentiate between the reflected light and luminescence. It is shown that more reliable results are achieved for this phosphor by measuring the reflectance using a synchronous zero-offset scan in a fluorescence spectrometer equipped with an integrating sphere. This method is therefore recommended instead of traditional reflectance measurements using a UV-vis spectrophotometer for luminescent powders.

Methods of optical spectroscopy and luminescence in analysis of natural and waste waters

International Nuclear Information System (INIS)

Koryakin, A.V.; Gribovskaya, I.F.

1987-01-01

The actual problem of analytical control of the state of water contamination by heavy metals, biogenic substances, organic compounds, are considered. Methods for sampling, storage and preparation of samples for analysis, preparation of standard solutions are described. Some theoretical statements making it possible to improve certain techniques are given alongside with methods of atomic emission, atomic absorption and luminescence analysis of water (determination of microquantities of transition metals, lanthanides, actinides, etc). Methods for increase of sensitivity and reliability of the analysis, its rapidity are described

Plasmon-enhanced optically stimulated luminescence

International Nuclear Information System (INIS)

Guidelli, E. J.; Baffa, O.; Ramos, A. P.

2015-10-01

Full text: Optically Stimulated Luminescence dosimeters (OSLD) have been largely used for personal, medical, and industrial radiation dosimetry. Developing highly sensitive and small-sized radiation detectors and dosimeters is essential for improving spatial resolution and consequently diagnosis quality and treatment efficacy in the case of applications in radiodiagnosis and radiation therapy, for instance. Conventional methods to improve the OSLD sensitivity consist of doping and co-doping the host materials with atoms of other elements, thereby increasing the amount of trapping and/or luminescent centers. Our group is researching on the use of the plasmon properties of noble metal nanoparticles to increase OSL intensity. Upon incidence of a light beam with appropriate resonant wavelengths, the oscillation of the free electrons at the nanoparticle surface originates the Localized Surface Plasmons (LSP) and the consequent plasmon resonance band. The interaction between the LSP and the surrounding luminescent material leads to new optical properties largely employed for enhancing several luminescent processes. Here we will show our results regarding the use of LSP to increase OSLD sensitivity. The interaction between the traps/luminescent centers and the plasmons depends on the distance between them, on the plasmon resonance band intensity and position, as well as on the surrounding medium. Therefore, the plasmon-enhanced luminescence is a promising tool to develop more sensitive and miniaturized OSLD. (Author)

Plasmon-enhanced optically stimulated luminescence

Energy Technology Data Exchange (ETDEWEB)

Guidelli, E. J.; Baffa, O. [Universidade de Sao Paulo, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Departamento de Fisica, Av. Bandeirantes 3900, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Ramos, A. P., E-mail: ederguidelli@gmail.com [Universidade de Sao Paulo, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Departamento de Quimica, Av. Bandeirantes 3900, 14040-901 Ribeirao Preto, Sao Paulo (Brazil)

2015-10-15

Full text: Optically Stimulated Luminescence dosimeters (OSLD) have been largely used for personal, medical, and industrial radiation dosimetry. Developing highly sensitive and small-sized radiation detectors and dosimeters is essential for improving spatial resolution and consequently diagnosis quality and treatment efficacy in the case of applications in radiodiagnosis and radiation therapy, for instance. Conventional methods to improve the OSLD sensitivity consist of doping and co-doping the host materials with atoms of other elements, thereby increasing the amount of trapping and/or luminescent centers. Our group is researching on the use of the plasmon properties of noble metal nanoparticles to increase OSL intensity. Upon incidence of a light beam with appropriate resonant wavelengths, the oscillation of the free electrons at the nanoparticle surface originates the Localized Surface Plasmons (LSP) and the consequent plasmon resonance band. The interaction between the LSP and the surrounding luminescent material leads to new optical properties largely employed for enhancing several luminescent processes. Here we will show our results regarding the use of LSP to increase OSLD sensitivity. The interaction between the traps/luminescent centers and the plasmons depends on the distance between them, on the plasmon resonance band intensity and position, as well as on the surrounding medium. Therefore, the plasmon-enhanced luminescence is a promising tool to develop more sensitive and miniaturized OSLD. (Author)

Anomalous enhancement of nanodiamond luminescence upon heating

Science.gov (United States)

Khomich, A. A.; Kudryavtsev, O. S.; Dolenko, T. A.; Shiryaev, A. A.; Fisenko, A. V.; Konov, V. I.; Vlasov, I. I.

2017-02-01

Characteristic photoluminescence (PL) of nanodiamonds (ND) of different origin (detonation, HPHT, extracted from meteorite) was studied in situ at high temperatures in the range 20-450 °C. Luminescence was excited using 473 nm laser and recorded in the range 500-800 nm. In contrast to decrease of point defect PL in bulk diamond with temperature, we found that the ND luminescence related to ND surface defects increases almost an order of magnitude upon heating to 200-250 °C. The observed effect reveals that water adsorbed on ND surfaces efficiently quenches PL; water desorption on heating leads to dramatic increase of the radiative de-excitation.

Synthesis and luminescence properties of (Zn,Cd)S:Ag nanocrystals by hydrothermal method

International Nuclear Information System (INIS)

Luo Xixian; Cao Wanghe; Zhou Lixin

2007-01-01

ZnS:Ag and (Zn,Cd)S:Ag nanoparticles with particle sizes of about 50 and 150 nm have been prepared by hydrothermal method. The effects of hydrothermal process on the physical and luminescence characteristics are investigated. The photoluminescence intensities of hydrothermal treatment ZnS:Ag samples are 10 times higher than that of non-treated samples after annealing at 800 deg. C

Fabrication and Spectral Properties of Wood-Based Luminescent Nanocomposites

Directory of Open Access Journals (Sweden)

Xianjun Li

2014-01-01

Full Text Available Pressure impregnation pretreatment is a conventional method to fabricate wood-based nanocomposites. In this paper, the wood-based luminescent nanocomposites were fabricated with the method and its spectral properties were investigated. The results show that it is feasible to fabricate wood-based luminescent nanocomposites using microwave modified wood and nanophosphor powders. The luminescent strength is in positive correlation with the amount of phosphor powders dispersed in urea-formaldehyde resin. Phosphors absorb UV and blue light efficiently in the range of 400–470 nm and show a broad band of bluish-green emission centered at 500 nm, which makes them good candidates for potential blue-green luminescent materials.

Luminescence dating

International Nuclear Information System (INIS)

Rieser, U.

2013-01-01

The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materials in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs.

Luminescence dating

International Nuclear Information System (INIS)

Rieser, U.

2009-01-01

The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materals in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs.

Luminescence dating

International Nuclear Information System (INIS)

Rieser, U.

2008-01-01

The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materals in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs

Luminescence dating

International Nuclear Information System (INIS)

Rieser, U.

2012-01-01

The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materials in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs.

Luminescence dating

International Nuclear Information System (INIS)

Rieser, U.

2009-01-01

The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materals in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs

Numerical dating of a Late Quaternary spit-shoreline complex at the northern end of Silver Lake playa, Mojave Desert, California: A comparison of the applicability of radiocarbon, luminescence, terrestrial cosmogenic nuclide, electron spin resonance, U-series and amino acid racemization methods

Science.gov (United States)

Owen, L.A.; Bright, Jordon; Finkel, R.C.; Jaiswal, M.K.; Kaufman, D.S.; Mahan, S.; Radtke, U.; Schneider, J.S.; Sharp, W.; Singhvi, A.K.; Warren, C.N.

2007-01-01

A Late Quaternary spit-shoreline complex on the northern shore of Pleistocene Lake Mojave of southeastern California, USA was studied with the goal of comparing accelerator mass spectrometry (AMS) radiocarbon, luminescence, electron spin resonance (ESR), terrestrial cosmogenic radionuclide (TCN) surface exposure, amino acid racemization (AAR) and U-series dating methods. The pattern of ages obtained by the different methods illustrates the complexity of processes acting in the lakeshore environment and highlights the utility of a multi-method approach. TCN surface exposure ages (mostly ???20-30 ka) record the initial erosion of shoreline benches, whereas radiocarbon ages on shells (determined in this and previous studies) within the spit, supported by AAR data, record its construction at fluctuating lake levels from ???16 to 10 ka. Luminescence ages on spit sediment (???6-7 ka) and ESR ages on spit shells (???4 ka) are anomalously young relative to radiocarbon ages of shells within the same deposits. The significance of the surprisingly young luminescence ages is not clear. The younger ESR ages could be a consequence of post-mortem enrichment of U in the shells. High concentrations of detrital thorium in tufa coating spit gravels inhibited the use of single-sample U-series dating. Detailed comparisons such as this provide one of the few means of assessing the accuracy of Quaternary dating techniques. More such comparisons are needed. ?? 2007 Elsevier Ltd and INQUA.

Luminescence and energy transfer

Energy Technology Data Exchange (ETDEWEB)

Blasse, G; Bleijenberg, K C; Powell, R C

1980-01-01

This paper deals with the luminescence of uranate centres in solids. The luminescence properties are influenced by the coordination number of the hexavalent uranium ion and by the crystallographic surroundings of the uranate centre. Transitions playing a role in the luminescence processes within the octahedral UO/sub 6//sup 6 -/ group are discussed using the results from both theoretical and experimental studies on another octahedral uranium complex: UF/sub 6/. The luminescence of the octahedral uranate group in oxidic compounds is discussed. Attention is paid to the vibrational structure, which is observed in the luminescence spectra at low temperatures and to the temperature quenching of the luminescence. The temperature quenching of the uranate luminescence in uranium-doped tungstates with ordered perovskite structure can be described in terms of a three state single configurational coordinate diagram. The complicated luminescence spectra of uranium-activated sodium fluoride (NaF-U) crystals have been unraveled using chemical variation of the crystal compositions and using site selective laser excitation techniques. Four different luminescent uranate centres have been observed in NaF-U. A model for the configurations of the luminescent centres has been deduced using the results from ionic conductivity experiments.

Time-resolved luminescence from quartz: An overview of contemporary developments and applications

Energy Technology Data Exchange (ETDEWEB)

Chithambo, M.L., E-mail: m.chithambo@ru.ac.za [Department of Physics and Electronics, Rhodes University, PO BOX 94, Grahamstown 6140 (South Africa); Ankjærgaard, C. [Soil Geography and Landscape Group, Wageningen University Netherlands Centre for Luminescence Dating, Droevendaalsesteeg 3, 6708 PB Wageningen, The Netherlands (Netherlands); Pagonis, V. [McDaniel College, Physics Department, Westminster, MD 21157 (United States)

2016-01-15

Time-resolved optical stimulation of luminescence has become established as a key method for measurement of optically stimulated luminescence from quartz, feldspar and α-Al{sub 2}O{sub 3}:C, all materials of interest in dosimetry. The aim of time-resolved optical stimulation is to separate in time the stimulation and emission of luminescence. The luminescence is stimulated from a sample using a brief light pulse and the emission monitored during stimulation in the presence of scattered stimulating light or after pulsing, over photomultiplier noise only. Although the use of the method in retrospective dosimetry has been somewhat limited, the technique has been successfully applied to study mechanisms in the processes leading up to luminescence emission. The main means for this has been the temperature dependence of the luminescence intensity as well as the luminescence lifetimes determined from time-resolved luminescence spectra. In this paper we review some key developments in theory and applications to quartz including methods of evaluating lifetimes, techniques of evaluating kinetic parameters using both the dependence of luminescence intensity and lifetime on measurement temperature, and of lifetimes on annealing temperature. We then provide an overview of some notable applications such as separation of quartz signals from a quartz–feldspar admixture and the utility of the dynamic throughput, a measure of luminescence measured as a function of the pulse width. The paper concludes with some suggestions of areas where further exploration would advance understanding of dynamics of luminescence in quartz and help address some outstanding problems in its application.

Synthesis and luminescent properties of Y(As, Nb, P, V)O4:Eu3+ red phosphors by combinatorial chemistry method

International Nuclear Information System (INIS)

Zeon, Il Woon; Park, Hee Dong; Sohn, Kee Sun; Ryu, Seung Kon

2001-01-01

Eu doped YRO 4 (R=As, Nb, P, V)red phosphors were prepared by the combinatorial chemistry method. The quaternary material library of tetrahedron-type composition array was designed to investigate the luminescence of the host material under UV and VUV excitations (254, 147 nm). The photoluminescent characteristics of the samples were comparable to the commercially available red phosphors such as (Y, Gd)BO 3 :Eu 3+ and Y 2 O 3 :Eu 3+ . In view of the luminescence yield, V rich region was found to be optimum under UV excitation. But the results under VUV excitation were different from those of UV excitation, the samples of the composition containing a large amount of P shows the highest luminescence. Especially, higher luminescence was obtained in Y 0.9 (As 0.06 Nb 0.06 P 0.83 V 0.06 )O 4 :Eu 0.1 phosphors than commercial (Y, Gd)BO 3 red phosphors under 147 nm excitation

Detection of Irradiated Korean Wheat Flour by Viscosity and Pulsed Photostimulated Luminescence (PPSL) Methods

International Nuclear Information System (INIS)

Yi, S.D.; Chang, K.S.; Oh, M.J.

2005-01-01

This study was carried out to establish methods for irradiation detection of irradiation in Korean wheat flour by pulsed photostimulated luminescence (PPSL) and viscometric methods. The photon counts of the irradiated Korean wheat flour measured by PPSL immediately after irradiation increased with increasing irradiation dose. The photon counts in the irradiated Korean wheat flour almost disappeared with lapse of time after storage in normal room conditions, but irradiation detection was still possible after 6 months in darkroom conditions

Conversion efficiency of implanted ions by confocal micro-luminescence mapping

International Nuclear Information System (INIS)

Deshko, Y.; Huang, Mengbing; Gorokhovsky, A.A.

2013-01-01

We report on the further development of the statistical approach to determine the conversion efficiency of implanted ions into emitting centers and present the measurement method based on the confocal micro-luminescence mapping. It involves the micro-luminescence mapping with a narrow-open confocal aperture, followed by the statistical analysis of the photoluminescence signal from an ensemble of emitting centers. The confocal mapping method has two important advantages compared to the recently discussed aperture-free method (J. Lumin. 131 (2011) 489): it is less sensitive to errors in the laser spot size and has a well defined useful area. The confocal mapping has been applied to the Xe center in diamond. The conversion efficiency has been found to be about 0.28, which is in good agreement with the results of the aperture-free method. - Highlights: ► Conversion efficiency of implanted ions into emitting centers – statistical approach. ► Micro-luminescence mapping with open and narrow confocal aperture – comparison. ► Advantages of the confocal micro-luminescence mapping. ► Confocal micro-luminescence mapping has been applied to the Xe center in diamond. ► The conversion efficiency has been found to be about 0.28.

Luminescence imaging using radionuclides: a potential application in molecular imaging

International Nuclear Information System (INIS)

Park, Jeong Chan; Il An, Gwang; Park, Se-Il; Oh, Jungmin; Kim, Hong Joo; Su Ha, Yeong; Wang, Eun Kyung; Min Kim, Kyeong; Kim, Jung Young; Lee, Jaetae; Welch, Michael J.; Yoo, Jeongsoo

2011-01-01

Introduction: Nuclear and optical imaging are complementary in many aspects and there would be many advantages when optical imaging probes are prepared using radionuclides rather than classic fluorophores, and when nuclear and optical dual images are obtained using single imaging probe. Methods: The luminescence intensities of various radionuclides having different decay modes have been assayed using luminescence imaging and in vitro luminometer. Radioiodinated Herceptin was injected into a tumor-bearing mouse, and luminescence and microPET images were obtained. The plant dipped in [ 32 P]phosphate solution was scanned in luminescence mode. Radio-TLC plate was also imaged in the same imaging mode. Results: Radionuclides emitting high energy β + /β - particles showed higher luminescence signals. NIH3T6.7 tumors were detected in both optical and nuclear imaging. The uptake of [ 32 P]phosphate in plant was easily followed by luminescence imaging. Radio-TLC plate was visualized and radiochemical purity was quantified using luminescence imaging. Conclusion: Many radionuclides with high energetic β + or β - particles during decay were found to be imaged in luminescence mode due mainly to Cerenkov radiation. 'Cerenkov imaging' provides a new optical imaging platform and an invaluable bridge between optical and nuclear imaging. New optical imaging probes could be easily prepared using well-established radioiodination methods. Cerenkov imaging will have more applications in the research field of plant science and autoradiography.

Quantitative luminescence imaging system

Science.gov (United States)

Erwin, David N.; Kiel, Johnathan L.; Batishko, Charles R.; Stahl, Kurt A.

1990-01-01

The QLIS images and quantifies low-level chemiluminescent reactions in an electromagnetic field. It is capable of real time nonperturbing measurement and simultaneous recording of many biochemical and chemical reactions such as luminescent immunoassays or enzyme assays. The system comprises image transfer optics, a low-light level digitizing camera with image intensifying microchannel plates, an image process or, and a control computer. The image transfer optics may be a fiber image guide with a bend, or a microscope, to take the light outside of the RF field. Output of the camera is transformed into a localized rate of cumulative digitalized data or enhanced video display or hard-copy images. The system may be used as a luminescent microdosimetry device for radiofrequency or microwave radiation, as a thermal dosimeter, or in the dosimetry of ultra-sound (sonoluminescence) or ionizing radiation. It provides a near-real-time system capable of measuring the extremely low light levels from luminescent reactions in electromagnetic fields in the areas of chemiluminescence assays and thermal microdosimetry, and is capable of near-real-time imaging of the sample to allow spatial distribution analysis of the reaction. It can be used to instrument three distinctly different irradiation configurations, comprising (1) RF waveguide irradiation of a small Petri-dish-shaped sample cell, (2) RF irradiation of samples in a microscope for the microscopie imaging and measurement, and (3) RF irradiation of small to human body-sized samples in an anechoic chamber.

Luminescence imaging of water during alpha particle irradiation

Science.gov (United States)

Yamamoto, Seiichi; Komori, Masataka; Koyama, Shuji; Toshito, Toshiyuki

2016-05-01

The luminescence imaging of water using the alpha particle irradiation of several MeV energy range is thought to be impossible because this alpha particle energy is far below the Cerenkov-light threshold and the secondary electrons produced in this energy range do not emit Cerenkov-light. Contrary to this consensus, we found that the luminescence imaging of water was possible with 5.5 MeV alpha particle irradiation. We placed a 2 MBq of 241Am alpha source in water, and luminescence images of the source were conducted with a high-sensitivity, cooled charge-coupled device (CCD) camera. We also carried out such imaging of the alpha source in three different conditions to compare the photon productions with that of water, in air, with a plastic scintillator, and an acrylic plate. The luminescence imaging of water was observed from 10 to 20 s acquisition, and the intensity was linearly increased with time. The intensity of the luminescence with the alpha irradiation of water was 0.05% of that with the plastic scintillator, 4% with air, and 15% with the acrylic plate. The resolution of the luminescence image of water was better than 0.25 mm FWHM. Alpha particles of 5.5 MeV energy emit luminescence in water. Although the intensity of the luminescence was smaller than that in air, it was clearly observable. The luminescence of water with alpha particles would be a new method for alpha particle detection and distribution measurements in water.

Luminescence imaging of water during alpha particle irradiation

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, Seiichi, E-mail: s-yama@met.nagoya-u.ac.jp [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine (Japan); Komori, Masataka; Koyama, Shuji [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine (Japan); Toshito, Toshiyuki [Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya City West Medical Center (Japan)

2016-05-21

The luminescence imaging of water using the alpha particle irradiation of several MeV energy range is thought to be impossible because this alpha particle energy is far below the Cerenkov-light threshold and the secondary electrons produced in this energy range do not emit Cerenkov-light. Contrary to this consensus, we found that the luminescence imaging of water was possible with 5.5 MeV alpha particle irradiation. We placed a 2 MBq of {sup 241}Am alpha source in water, and luminescence images of the source were conducted with a high-sensitivity, cooled charge-coupled device (CCD) camera. We also carried out such imaging of the alpha source in three different conditions to compare the photon productions with that of water, in air, with a plastic scintillator, and an acrylic plate. The luminescence imaging of water was observed from 10 to 20 s acquisition, and the intensity was linearly increased with time. The intensity of the luminescence with the alpha irradiation of water was 0.05% of that with the plastic scintillator, 4% with air, and 15% with the acrylic plate. The resolution of the luminescence image of water was better than 0.25 mm FWHM. Alpha particles of 5.5 MeV energy emit luminescence in water. Although the intensity of the luminescence was smaller than that in air, it was clearly observable. The luminescence of water with alpha particles would be a new method for alpha particle detection and distribution measurements in water.

Luminescence spectroscopy with synchrotron radiation: History, highlights, future

International Nuclear Information System (INIS)

Zimmerer, Georg

2006-01-01

Luminescence spectroscopy and the investigation of dynamical processes with synchrotron radiation (SR) started about 35 years ago in nearly all SR laboratories existing at that time. In the present paper, the pioneering experiments are particularly emphasized. The exciting development is illustrated presenting highlights for the whole period from the beginning to the present day. The highlights are taken from fields like exciton self-trapping, inelastic electron-electron scattering, optically stimulated desorption, cross luminescence, or probing of cluster properties with luminescence spectroscopic methods. More technological aspects play a role in present day's experiments, like quantum cutting in rare-earth-doped insulators. Promising two-photon excitation and light amplification experiments with SR will be included, as well as the first results obtained in a luminescence experiment with selective Vaccum ultraviolet-free electron laser excitation. Finally, a few ideas concerning the future development of luminescence spectroscopy with SR will be sketched

Bright white upconversion luminescence from Er3+/Tm3+/Yb3+-doped titanate-based glasses prepared by aerodynamic levitation method

Science.gov (United States)

Zhang, Minghui; Yu, Jianding; Jiang, Wan; Liu, Yan; Ai, Fei; Wen, Haiqin; Jiang, Meng; Yu, Huimei; Pan, Xiuhong; Tang, Meibo; Gai, Lijun

2017-10-01

Aerodynamic levitation method was employed to prepare Er3+/Tm3+/Yb3+-doped titanate-based glasses. DTA results show that the glass performs high thermal stability with the glass transition temperature of 799 °C. The interaction among rare earth ions has been discussed by adjusting the relative concentration. Er3+ ions can quench the upconversion luminescence of Tm3+ ions. Tm3+ ions play a strong role in quenching the emissions of Er3+ and Tm3+ when the content of Tm3+ ions is greater than or equal 0.05. From the view of the ratio of red emission to green emission, Tm3+ ions can improve the red emission of Er3+ ions to some extent in contrast with the green emissions of Er3+ ions. 980 nm incident laser can be efficiently absorbed by Yb3+ ions. The relative intensity of red, green, and blue upconversion luminescence has been tuned to obtain white light. The composition with white upconversion luminescence of the color coordinate (0.291, 0.3292) has been found. Moreover, white upconversion luminescence mechanism is a two-photon process of ET, ESA, and cooperative sensitization. Rare earth ions doped titanate-based glasses with bright upconversion luminescence perform potential applications in color display, back light, et al.

Intrinsic luminescence of un-doped borate glasses

International Nuclear Information System (INIS)

Kindrat, I.I.; Padlyak, B.V.; Drzewiecki, A.

2017-01-01

The nature of intrinsic luminescence in the un-doped borate glasses of different compositions has been investigated using spectroscopic methods including photoluminescence, optical absorption, electron paramagnetic resonance (EPR), and thermally stimulated luminescence (TSL). The un-doped borate glasses with Li 2 B 4 O 7 , LiKB 4 O 7 , CaB 4 O 7 , and LiCaBO 3 basic compositions were obtained from corresponding polycrystalline compounds in the air with usage the standard technology of glasses. Three different broad emission bands in the UV–Visible spectral range have been observed under different wavelength of photoexcitation. The luminescence kinetics of the observed emission bands have been registered and analysed. The nature and possible mechanisms of the intrinsic luminescence in the investigated borate glasses are considered and discussed based on the obtained results and referenced data.

Photoluminescence, reddish orange long persistent luminescence and photostimulated luminescence properties of praseodymium doped CdGeO3 phosphor

International Nuclear Information System (INIS)

Jin, Yahong; Hu, Yihua; Chen, Li; Fu, Yinrong; Mu, Zhongfei; Wang, Tao; Lin, Jun

2014-01-01

Highlights: • A novel phosphor CdGeO 3 :Pr 3+ was synthesized successfully. • The persistent luminescence properties of CdGeO 3 :Pr 3+ were studied. • The photostimulated luminescence properties of CdGeO 3 :Pr 3+ were investigated. • The persistent and photostimulated luminescence mechanisms were discussed in detail. - Abstract: Praseodymium doped CdGeO 3 phosphors were prepared successfully by a conventional high temperature solid-state reaction method. It showed reddish orange long persistent luminescence (LPL) after the short UV-irradiation. The reddish orange photostimulated luminescence (PSL) was also observed upon near infrared stimulation at 980 nm after per-exposure into UV light. The origin of LPL and PSL was identified with the emission from Pr 3+ ions with the aid of traps in host lattice. The optimal concentration of Pr 3+ ions for the brightest photoluminescence (PL) emission and the best LPL characteristic were experimentally to be about 3% and 0.5 mol%, respectively. The trapping and de-trapping processes of charge carriers between shallower and deep traps were illustrated. A model was proposed on the basis of experimental results to study the mechanisms of LPL and PSL

Measuring modulated luminescence using non-modulated stimulation: Ramping the sample period

DEFF Research Database (Denmark)

Poolton, N.R.J.; Bøtter-Jensen, L.; Andersen, C.E.

2003-01-01

. Directly analogous results to LM-OSL can, however, be achieved with non-modulated excitation sources, by ramping the sample period (RSP) of luminescence detection. RSP-OSL has the distinct advantage over LM-OSL in that, since the excitation remains at full power, data accumulation times (that can...... be considerable) can be reduced by typically 50%. RSP methods are universally applicable and can be employed, for example, where the excitation source is constant heat, rather than light: here, iso-thermal decay of phosphorescence becomes recorded as a sequence of peaks, corresponding to de-trapping of charge...

Luminescence of CdSe/ZnS quantum dots infiltrated into an opal matrix

International Nuclear Information System (INIS)

Gruzintsev, A. N.; Emelchenko, G. A.; Masalov, V. M.; Yakimov, E. E.; Barthou, C.; Maitre, A.

2009-01-01

The effect of the photonic band gap in the photonic crystal, the synthesized SiO 2 opal with embedded CdSe/ZnS quantum dots, on its luminescence in the visible spectral region is studied. It is shown that the position of the photonic band gap in the luminescence and reflectance spectra for the infiltrated opal depends on the diameter of the constituent nanospheres and on the angle of recording the signal. The optimal conditions for embedding the CdSe/ZnS quantum dots from the solution into the opal matrix are determined. It is found that, for the opal-CdSe/ZnS nanocomposites, the emission intensity decreases and the luminescence decay time increases in the spatial directions, in which the spectral positions of the photonic band gap and the luminescence peak of the quantum dots coincide.

Luminescence investigation of R{sup 3+}-doped alkaline earth tungstates prepared by a soft chemistry method

Energy Technology Data Exchange (ETDEWEB)

Barbosa, Helliomar P. [Instituto de Química, Universidade de São Paulo, São Paulo, SP (Brazil); Kai, Jiang [Pontifícia Universidade Católica do Rio de Janeiro, Departamento de Química, Rio de Janeiro, RJ, Brazil (Brazil); Silva, Ivan G.N.; Rodrigues, Lucas C.V. [Instituto de Química, Universidade de São Paulo, São Paulo, SP (Brazil); Felinto, Maria C.F.C. [Centro de Química e Meio Ambiente, Instituto de Pesquisas Energéticas e Nucleares, São Paulo, SP (Brazil); Hölsä, Jorma [Instituto de Química, Universidade de São Paulo, São Paulo, SP (Brazil); Department of Chemistry, University of Turku,FI-20014 Turku (Finland); Turku University Centre for Materials and Surfaces (MatSurf), Turku (Finland); Malta, Oscar L. [Departamento de Química Fundamental, Universidade Federal de Pernambuco, Recife, PE (Brazil); Brito, Hermi F., E-mail: hefbrito@iq.usp.br [Instituto de Química, Universidade de São Paulo, São Paulo, SP (Brazil)

2016-02-15

Highly luminescent rare earth (R{sup 3+}) doped alkaline-earth tungstates MWO{sub 4}:R{sup 3+} (M{sup 2+}: Ca, Sr and Ba, R{sup 3+}: Eu, Tb, Gd) were prepared with a room temperature coprecipitation method. The phosphors were characterized by X-ray powder diffraction (XPD), thermal analysis (TG), infrared absorption spectroscopy (FTIR) and UV excited photoluminescence. The as-prepared MWO{sub 4}:R{sup 3+} particles belong to the tetragonal scheelite phase, and are well crystallized and are of the average size of 16–48 nm. The excitation and emission spectra of the materials were recorded at 300 and 77 K temperatures. The luminescent materials exhibit intense red (Eu{sup 3+}) and green (Tb{sup 3+}) colors under UV excitation. The excitation spectra of the Eu{sup 3+} doped materials show broad bands arising from the ligand-to-metal charge transfer transitions (O{sup 2−}→W{sup VI} and O{sup 2−}→Eu{sup 3+}) as well as narrow bands from 4f–4f intraconfigurational transitions of Eu{sup 3+}. 4f–4f emission data of the Eu{sup 3+} and Tb{sup 3+} in the MWO{sub 4} host matrices as well as the values of emission quantum efficiencies of the {sup 5}D{sub 0} level and the 4f–4f experimental intensity parameters of Eu{sup 3+} ion are presented and discussed. - Highlights: • Highly red Europium and green Terbium doped tungstate under UV excitation. • Efficient energy transfer process from tungstate to R{sup 3+} ion. • Promising candidates for a red (Eu{sup 3+}) and green (Tb{sup 3+}) emitting phosphors. • Ligand Metal charge transfer to R{sup 3+} ion. • Charge compensation with Na{sup +}.

Luminescence basic concepts, applications and instrumentation

CERN Document Server

Virk, Hardev Singh

2014-01-01

The word luminescence was first used by a German physicist, Eilhardt Wiedemann, in 1888. He also classified luminescence into six kinds according to the method of excitation. No better basis of classification is available today. He recognized photoluminescence, thermoluminescence, electroluminescence, crystalloluminescence, triboluminescence, and chemiluminescence. The designations are obvious, characterized by the prefix. This Volume consists of 9 Chapters, including 8 Review Papers and one Case Study. The first two papers are based on OLEDs. Organic light emitting diodes (OLEDs) have been th

Luminescence imaging of water during proton-beam irradiation for range estimation

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, Seiichi, E-mail: s-yama@met.nagoya-u.ac.jp; Okumura, Satoshi; Komori, Masataka [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya 461-8673 (Japan); Toshito, Toshiyuki [Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya City West Medical Center, Nagoya 462-8508 (Japan)

2015-11-15

Purpose: Proton therapy has the ability to selectively deliver a dose to the target tumor, so the dose distribution should be accurately measured by a precise and efficient method. The authors found that luminescence was emitted from water during proton irradiation and conjectured that this phenomenon could be used for estimating the dose distribution. Methods: To achieve more accurate dose distribution, the authors set water phantoms on a table with a spot scanning proton therapy system and measured the luminescence images of these phantoms with a high-sensitivity, cooled charge coupled device camera during proton-beam irradiation. The authors imaged the phantoms of pure water, fluorescein solution, and an acrylic block. Results: The luminescence images of water phantoms taken during proton-beam irradiation showed clear Bragg peaks, and the measured proton ranges from the images were almost the same as those obtained with an ionization chamber. Furthermore, the image of the pure-water phantom showed almost the same distribution as the tap-water phantom, indicating that the luminescence image was not related to impurities in the water. The luminescence image of the fluorescein solution had ∼3 times higher intensity than water, with the same proton range as that of water. The luminescence image of the acrylic phantom had a 14.5% shorter proton range than that of water; the proton range in the acrylic phantom generally matched the calculated value. The luminescence images of the tap-water phantom during proton irradiation could be obtained in less than 2 s. Conclusions: Luminescence imaging during proton-beam irradiation is promising as an effective method for range estimation in proton therapy.

Luminescence imaging of water during proton-beam irradiation for range estimation

International Nuclear Information System (INIS)

Yamamoto, Seiichi; Okumura, Satoshi; Komori, Masataka; Toshito, Toshiyuki

2015-01-01

Purpose: Proton therapy has the ability to selectively deliver a dose to the target tumor, so the dose distribution should be accurately measured by a precise and efficient method. The authors found that luminescence was emitted from water during proton irradiation and conjectured that this phenomenon could be used for estimating the dose distribution. Methods: To achieve more accurate dose distribution, the authors set water phantoms on a table with a spot scanning proton therapy system and measured the luminescence images of these phantoms with a high-sensitivity, cooled charge coupled device camera during proton-beam irradiation. The authors imaged the phantoms of pure water, fluorescein solution, and an acrylic block. Results: The luminescence images of water phantoms taken during proton-beam irradiation showed clear Bragg peaks, and the measured proton ranges from the images were almost the same as those obtained with an ionization chamber. Furthermore, the image of the pure-water phantom showed almost the same distribution as the tap-water phantom, indicating that the luminescence image was not related to impurities in the water. The luminescence image of the fluorescein solution had ∼3 times higher intensity than water, with the same proton range as that of water. The luminescence image of the acrylic phantom had a 14.5% shorter proton range than that of water; the proton range in the acrylic phantom generally matched the calculated value. The luminescence images of the tap-water phantom during proton irradiation could be obtained in less than 2 s. Conclusions: Luminescence imaging during proton-beam irradiation is promising as an effective method for range estimation in proton therapy

Transition Metal Complexes as Photosensitizers for Near-Infrared Lanthanide Luminescence

NARCIS (Netherlands)

Klink, S.I.; Keizer, Henk; van Veggel, F.C.J.M.

2000-01-01

We thank Roel Fokkens and Nico Nibbering (University of Amsterdam) for recording and discussing the MALDI-TOF mass spectra. Martijn Werts (University of Amsterdam) is gratefully acknowledged for his support with the time-resolved luminescence measurements. This research has been financially

Luminescence Dating of Martian Polar Deposits: Concepts and Preliminary Measurements Using Martian Soil Analogs

Science.gov (United States)

Lepper, K.; Kuhns, C. K.; McKeever, S. W. S.; Sears, D. W. G.

2000-08-01

Martian polar deposits have the potential to reveal a wealth of information about the evolution of Mars' climate and surface environment. However, as pointed out by Clifford et al. in the summary of the First International Conference on Mars Polar Science and Exploration, 'The single greatest obstacle to unlocking and interpreting the geologic and climatic record preserved at the [martian] poles is the need for absolute dating.' At that same conference Lepper and McKeever proposed development of luminescence dating as a remote in-situ technique for absolute dating of silicate mineral grains incorporated in polar deposits. Clifford et al. have also acknowledged that luminescence dating is more practical from cost, engineering, and logistical perspectives than other isotope-based methods proposed for in-situ dating on Mars. We report here the results of ongoing experiments with terrestrial analogs of martian surface materials to establish a broad fundamental knowledge base from which robust dating procedures for robotic missions may be developed. This broad knowledge base will also be critical in determining the engineering requirements of remote in-situ luminescence dating equipment intended for use on Mars. Additional information can be found in the original extended abstract.

Magnetic-luminescent spherical particles synthesized by ultrasonic spray pyrolysis

International Nuclear Information System (INIS)

Michel, Norma L; Hirata, Gustavo A; Flores, Dora L

2015-01-01

The combination of magnetic and luminescent properties in a single particle system, opens-up a wide range of potential applications in biotechnology and biomedicine. In this work, we performed the synthesis of magnetic-luminescent Gd 2 O 3 :Eu 3+ @Fe 2 O 3 particles by ultrasonic spray pyrolysis performed in a tubular furnace. In order to achieve the composite formation, commercial superparamagnetic Fe 3 O 4 nanoparticles were coated with a luminescent Eu 3+ -doped Gd 2 O 3 shell in a low-cost one-step process. The spray pyrolysis method yields deagglomerated spherical shape magneto/luminescent particles. The photoluminescence spectra under UV excitation (λ Exc = 265 nm) of the magnetic Gd 2 O 3 :Eu 3+ @Fe 2 O 3 compound showed the characteristic red emission of Eu 3+ (λ Em = 612 nm). This magneto/luminescent system will find applications in biomedicine and biotechnology. (paper)

Dependence of the thermal influence on luminescence lifetimes from quartz on the duration of optical stimulation

International Nuclear Information System (INIS)

Chithambo, M.L.

2003-01-01

Time-resolved luminescence spectra may be measured from quartz at various stages of continuous optical stimulation in order to investigate properties of the spectra associated with the 'fast', 'medium', and 'slow' components of continuous optically stimulated luminescence (OSL). In this work, temperature related changes of luminescence lifetimes and luminescence intensity, both evaluated from time-resolved luminescence spectra recorded in the 'fast' 'medium' and 'slow' component regions of quartz OSL, have been investigated. The luminescence, stimulated at 525 nm, and measured at intervals between 20 deg. C and 200 deg. C reaches maximum intensity at 100 deg. C and decreases thereafter up to 200 deg. C, the maximum temperature of the investigations. Luminescence lifetimes, on the other hand, remain constant within 40±3 μs between 20 deg. C and 100 deg. C and then decrease down to about μs at 200 deg. C. The initial increase of luminescence intensity with temperature between 20 deg. C and 100 deg. C is discussed in terms of thermal assistance to luminescence stimulation. Beyond 100 deg. C, radiative recombination is affected by quenching of luminescence and reduction in luminescence lifetimes. The activation energy for thermal quenching was evaluated to be in the range 0.63±0.07 eV at all stimulation times and that of thermal assistance was evaluated to be about 0.06 eV for the 'fast' and 'medium' component regions and about 0.1 eV for the 'slow' component region of the OSL

Device for the evaluation of radio-photo-luminescent glasses

International Nuclear Information System (INIS)

Hoegl, A.; Schubert, K.

1979-01-01

The UV light for irradiation of the glass as well as the luminescent light generated by the UV light are recorded in different measuring circuits. Intensity variations of the UV light source are corrected by a programmed control system and a comparing and correcting device linking both measuring circuits with one another and containing integrating stages as well as a-d converters. In order to eliminate the influence of sensitivity variations of the light converter and of the amplifying level of the succeeding amplifier a reference light source is added to the light converter. The programmed control system causes alternating measuring phases of luminescence and reference light. The correction is done by the comparing and correcting unit. (DG) [de

Luminescence and radiocarbon dating of raised beach sediments, Bunger Hills, East Antarctica

International Nuclear Information System (INIS)

Augustinus, P.C.; Duller, G.A.T.

2002-01-01

Luminescence and radiocarbon dating of raised marine sediments from the Bunger Hills, East Antarctica, demonstrates that luminescence methods can be applied to such poorly bleached sediments as long as the luminescence behaviour of the sediments is understood. This is essential as the complete zeroing of the luminescence signal due to light exposure is required to allow an accurate age for the sediment accumulation. Unfortunately, independent checks on the luminescence ages are rare. In the present study, some independent age control is provided by AMS radiocarbon ages from shell obtained from and adjacent to the luminescence dated horizons, although the radiocarbon ages may suffer to some degree from variability in the marine reservoir effect. Application of the single aliquot luminescence technique to feldspar grains from the marine sediments demonstrated that the luminescence behaviour of the sediments was complex. For each sample, 18 replicate paleodose estimates were used to demonstrate whether the sediments were well bleached before deposition. Optically, well-bleached samples give younger luminescence ages, whilst poorly bleached samples often give excessively old ages compared to the associated radiocarbon-dated material. (author)

Luminescent micro- and nanofibers based on novel europium phthalate complex

Energy Technology Data Exchange (ETDEWEB)

Enculescu, M., E-mail: mdatcu@infim.ro [National Institute of Materials Physics, Multifunctional Materials and Structures, PO Box MG-7, 77125 Magurele-Bucharest (Romania); Preda, N.; Matei, E.; Enculescu, I. [National Institute of Materials Physics, Multifunctional Materials and Structures, PO Box MG-7, 77125 Magurele-Bucharest (Romania)

2012-09-14

We synthesized by wet chemical route a novel europium-potassium phthalate complex Eu{sup 3+}K{sup +}[(COO){sub 2}(C{sub 6}H{sub 4})]{sub 2}. The compound is a white powder insoluble in water. X-ray diffraction evaluation shows that we obtained a new crystalline compound with no traces of the starting materials (potassium hydrogen phthalate and europium chloride). Scanning electron microscopy reveals that the powder consists of fiber-shaped structures with sizes larger than 250 nm in diameter. Energy dispersive X-ray analysis proves that the compound has a 1:1 europium-potassium ratio. Fourier transform infrared spectroscopy confirms the presence of the phthalate in the new compound. Photoluminescence and cathodoluminescence measurements show that the fiber-shaped structures are intensely luminescent with emission bands corresponding to the {sup 5}D{sub 0} {yields} {sup 7}F{sub J} (J = 1-4) Eu (III) ion's transitions in the region between 580 nm and 700 nm, the most intense maximum being observed around 615 nm. Up-converted luminescence with a maximum at 315 nm was recorded. -- Highlights: Black-Right-Pointing-Pointer A new europium-potassium phthalate complex was synthesized by wet chemical route. Black-Right-Pointing-Pointer Fiber-shaped crystalline structures with sizes larger than 250 nm. Black-Right-Pointing-Pointer The most probable structure of the molecule is [C{sub 6}H{sub 4}(COO{sup -}){sub 2}]{sub 2} K{sup +}Eu{sup 3+}. Black-Right-Pointing-Pointer Intense luminescence due to Eu{sup 3+} ions {sup 5}D{sub 0} {yields} {sup 7}F{sub J} transitions. Black-Right-Pointing-Pointer Up-converted luminescence with a maximum at 315 nm was recorded.

Luminescence and photosensitivity of PbI2 crystals

International Nuclear Information System (INIS)

Novosad, S.S.; Novosad, I.S.; Matviishin, I.M.

2002-01-01

One studied effect of temperature treatment and storage conditions on spectra features of PbI 2 crystals grown by the Bridgman-Stockbarger method from salt additionally purified by directed crystallization. Spectra of X-ray luminescence, photoluminescence and thermostimulated luminescence were investigated within 85-295 K temperature range under stationary X-ray excitation and emission of N 2 -laser. One studied photoelectret properties of those crystals under 85 K. Luminescence of PbI 2 crystals with maximum within 595 nm region observed following their thermal annealing under 475-495 K temperature and typical for near-the-surface section of specimens may be caused by oxygen-containing centres [ru

Plasmon-enhanced luminescence of Sm complex using silver nanoparticles in Polyvinyl Alcohol

Energy Technology Data Exchange (ETDEWEB)

Kaur, Gagandeep; Verma, R.K.; Rai, D.K. [Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, India 221005 (India); Rai, S.B., E-mail: sbrai49@yahoo.co.in [Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, India 221005 (India)

2012-07-15

Silver (Ag) nanoparticles (NPs) were prepared by laser ablation in water with an aim to enhance the luminescence of rare earth coordinated complex in polymer host. A fixed concentration of the complex containing Samarium (Sm), Salicylic acid (Sal) and 1, 10-phenanthroline (Phen) were combined with different concentrations of silver NPs in PolyVinyl Alcohol at room temperature. Absorption spectrum and XRD patterns of the sample show that the Sm(Sal){sub 3}Phen complex is accompanied by Ag NPs. The luminescence from the complex was recorded in the presence and absence of Ag NPs using two different excitation wavelengths viz. 400 and 355 nm. Of these, 400 nm radiation falls in the surface plasmon resonance of Ag NPs. It was found that the Ag NPs led to a significant enhancement in luminescence of the complex. Surprisingly, a high concentration of Ag NPs tends to quench the luminescence. - Highlights: Black-Right-Pointing-Pointer Sm complex with Ag nanoparticles in PVA was prepared at room temperature. Black-Right-Pointing-Pointer UV-vis absorption and XRD confirms the presence of Sm complex and Ag NPs. Black-Right-Pointing-Pointer Enhancement in luminescence of complex was observed with Ag NPs. Black-Right-Pointing-Pointer Coupling between radiative transitions of Sm and SPR of NPs enhances the emission. Black-Right-Pointing-Pointer The higher concentration of Ag NPs quenches the luminescence of the complex.

Luminescence centers in bismuth orthogermanate

International Nuclear Information System (INIS)

Bordun, O.M.

2001-01-01

The luminescence and photoexcitation spectra of single crystals,ceramics,and thin films of Bi 4 Ce 3 O 1 2 are studied.The decomposition of the luminescence spectra into elementary components by the Alentsev-Fock method showed that they consist of three bands with maxima at 2.7,2.4,and 2.05 eV.The bands with maxima at 2.7 and 2.4 eV are assigned to the emission of self-trapped Frenkel excitons describing the excited state of a (BiO 6 ) 9- molecular ion. Emission bands with maxima at 2.0 5 eV are assigned to recombination on traps caused by structural defects

Novel lanthanide doped micro- and mesoporous solids. Characterization of ion-host-interactions, species distribution and luminescence properties using time-resolved luminescence spectroscopy

International Nuclear Information System (INIS)

Gessner, Andre

2010-12-01

In this work lanthanide-doped microporous zeolites, microporous-mesoporous hybrid materials and mesoporous silicates were investigated regarding their luminescence properties and the ion-host-interactions using time-resolved luminescence spectroscopy. Thereby, time-resolved emission spectra (TRES) provide information in the wavelength and time domain. For the analysis of the TRES a broad set of analytic methods was applied and thus a corresponding ''toolbox'' developed. Fitting of the luminescence decays was performed with a discrete number of exponentials and supported by luminescence decay times distributions. Time-resolved area normalized emission spectra (TRANES), an advancement of TRES, could be used for the determination of the number of emissive lanthanide species in porous materials for the first time. Calculation of the decay-associated spectra (DAS) allowed the correlation of spectral information with luminescence decay times and thus delivered the luminescence spectra of the different europium species. For europium(III) we could use in addition the time-dependent asymmetry ratio and spectral evolution of the 5 D 0 - 7 F 0 -transition with time to obtain further information about the distribution of the lanthanide ions in the host material. Luminescence decay times and spectra allowed conclusions on the number of OH-oscillators in and the symmetry of the first coordination sphere. For the microporous and microporous-mesoporous materials were found different lanthanide species, which were characterized by the above mentioned methods. These lanthanide species can be found on different positions in the host material. One position is located deep in the pore system. Here, lanthanide ions are hardly accessible for water and mainly coordinated by framework oxygens. This results in long luminescence decay times and distorted coordination spheres. The second position can be found near or on the outer surface or in the mesopores. Lanthanide ions located here, are

Mathematical model quantifies multiple daylight exposure and burial events for rock surfaces using luminescence dating

DEFF Research Database (Denmark)

Freiesleben, Trine Holm; Sohbati, Reza; Murray, Andrew

2015-01-01

Interest in the optically stimulated luminescence (OSL) dating of rock surfaces has increased significantly over the last few years, as the potential of the method has been explored. It has been realized that luminescence-depth profiles show qualitative evidence for multiple daylight exposure...... and burial events. To quantify both burial and exposure events a new mathematical model is developed by expanding the existing models of evolution of luminescenceedepth profiles, to include repeated sequential events of burial and exposure to daylight. This new model is applied to an infrared stimulated...... events. This study confirms the suggestion that rock surfaces contain a record of exposure and burial history, and that these events can be quantified. The burial age of rock surfaces can thus be dated with confidence, based on a knowledge of their pre-burial light exposure; it may also be possible...

Luminescent solar concentrator

Directory of Open Access Journals (Sweden)

Tugce Tosun

2015-07-01

Full Text Available Luminescent solar concentrator (LSC is a device that has luminescent molecules embedding or topping polymeric or glass waveguide to generate electricity from sunlight with a photovoltaic cell attachment. LSCs can be employed both in small and large scale projects, independent on the direction or angle of the surface with respect to the sun, promising more freedom for integration in urban environments compared to the traditional PV systems. The aim of the SEB&C PDEng project is to investigate the applicability of this innovative technology in the built environment and to bridge the gap of knowledge linking societal, design and technological aspects. The final goal is to exhibit potential application concepts of LSC developed by co-creative methods at SPARK campus which is a hub for open innovation in built environment. Necessity of a paradigm shift towards sustainable and smart cities came into being due to the significant increase in energy demand of the buildings. The challenge is to increase renewable sources in the energy mix while designing aesthetic environments. Thus, building integrated renewable energy technologies represent a great opportunity to help overcome this current challenge. Smart energy, energy efficiency and use of renewable sources are key aspects to be considered nowadays and many innovative technologies need further exploitation to be commercially viable, such as luminescent solar concentrator.

Radiation ray discrimination method using photo-stimulated luminescence fluorescent material

International Nuclear Information System (INIS)

Atsumi, Yoshihiro; Takebe, Masahiro; Abe, Ken.

1996-01-01

An IP (imaging plate) using PSL (photo-stimulated luminescence fluorescent material) is formed by coating a photo-stimulated luminescence fluorescent material on a thin plastic plate. A predetermined colorants is added to the PSL material. A colorant which absorbs a light having a wavelength of about 600nm is preferred. After irradiating various kinds of radiation rays to the IP, and then irradiating a white light thereto for a predetermined period of time, lights at several kinds of wavelength specific to several kinds of radiation rays to be measured are successively irradiated to the IP. The ratios between the luminance intensity of the fluorescent light emitted from the IP in this case and that emitted when a light of one specific wavelength is irradiated are successively calculated. The light of the specific wavelength preferably has a wavelength of 600nm. With such procedures, the kinds of the several radiation rays which are irradiated to the IP can be discriminated. (I.N.)

Temperature and Pressure Sensors Based on Spin-Allowed Broadband Luminescence of Doped Orthorhombic Perovskite Structures

Science.gov (United States)

Eldridge, Jeffrey I. (Inventor); Chambers, Matthew D. (Inventor)

2014-01-01

Systems and methods that are capable of measuring pressure or temperature based on luminescence are discussed herein. These systems and methods are based on spin-allowed broadband luminescence of sensors with orthorhombic perovskite structures of rare earth aluminates doped with chromium or similar transition metals, such as chromium-doped gadolinium aluminate. Luminescence from these sensors can be measured to determine at least one of temperature or pressure, based on either the intense luminescence of these sensors, even at high temperatures, or low temperature techniques discussed herein.

Positron-Induced Luminescence

Science.gov (United States)

Stenson, E. V.; Hergenhahn, U.; Stoneking, M. R.; Pedersen, T. Sunn

2018-04-01

We report on the observation that low-energy positrons incident on a phosphor screen produce significantly more luminescence than electrons do. For two different wide-band-gap semiconductor phosphors (ZnS:Ag and ZnO:Zn), we compare the luminescent response to a positron beam with the response to an electron beam. For both phosphors, the positron response is significantly brighter than the electron response, by a factor that depends strongly on incident energy (0-5 keV). Positrons with just a few tens of electron-volts of energy (for ZnS:Ag) or less (for ZnO:Zn) produce as much luminescence as is produced by electrons with several kilo-electron-volts. We attribute this effect to valence band holes and excited electrons produced by positron annihilation and subsequent Auger processes. These results demonstrate a valuable approach for addressing long-standing questions about luminescent materials.

Luminescence imaging of water during carbon-ion irradiation for range estimation

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, Seiichi, E-mail: s-yama@met.nagoya-u.ac.jp; Komori, Masataka; Koyama, Shuji; Morishita, Yuki; Sekihara, Eri [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, Higashi-ku, Nagoya, Aichi 461-8673 (Japan); Akagi, Takashi; Yamashita, Tomohiro [Hygo Ion Beam Medical Center, Hyogo 679-5165 (Japan); Toshito, Toshiyuki [Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya City West Medical Center, Aichi 462-8508 (Japan)

2016-05-15

Purpose: The authors previously reported successful luminescence imaging of water during proton irradiation and its application to range estimation. However, since the feasibility of this approach for carbon-ion irradiation remained unclear, the authors conducted luminescence imaging during carbon-ion irradiation and estimated the ranges. Methods: The authors placed a pure-water phantom on the patient couch of a carbon-ion therapy system and measured the luminescence images with a high-sensitivity, cooled charge-coupled device camera during carbon-ion irradiation. The authors also carried out imaging of three types of phantoms (tap-water, an acrylic block, and a plastic scintillator) and compared their intensities and distributions with those of a phantom containing pure-water. Results: The luminescence images of pure-water phantoms during carbon-ion irradiation showed clear Bragg peaks, and the measured carbon-ion ranges from the images were almost the same as those obtained by simulation. The image of the tap-water phantom showed almost the same distribution as that of the pure-water phantom. The acrylic block phantom’s luminescence image produced seven times higher luminescence and had a 13% shorter range than that of the water phantoms; the range with the acrylic phantom generally matched the calculated value. The plastic scintillator showed ∼15 000 times higher light than that of water. Conclusions: Luminescence imaging during carbon-ion irradiation of water is not only possible but also a promising method for range estimation in carbon-ion therapy.

Luminescence imaging of water during carbon-ion irradiation for range estimation

International Nuclear Information System (INIS)

Yamamoto, Seiichi; Komori, Masataka; Koyama, Shuji; Morishita, Yuki; Sekihara, Eri; Akagi, Takashi; Yamashita, Tomohiro; Toshito, Toshiyuki

2016-01-01

Purpose: The authors previously reported successful luminescence imaging of water during proton irradiation and its application to range estimation. However, since the feasibility of this approach for carbon-ion irradiation remained unclear, the authors conducted luminescence imaging during carbon-ion irradiation and estimated the ranges. Methods: The authors placed a pure-water phantom on the patient couch of a carbon-ion therapy system and measured the luminescence images with a high-sensitivity, cooled charge-coupled device camera during carbon-ion irradiation. The authors also carried out imaging of three types of phantoms (tap-water, an acrylic block, and a plastic scintillator) and compared their intensities and distributions with those of a phantom containing pure-water. Results: The luminescence images of pure-water phantoms during carbon-ion irradiation showed clear Bragg peaks, and the measured carbon-ion ranges from the images were almost the same as those obtained by simulation. The image of the tap-water phantom showed almost the same distribution as that of the pure-water phantom. The acrylic block phantom’s luminescence image produced seven times higher luminescence and had a 13% shorter range than that of the water phantoms; the range with the acrylic phantom generally matched the calculated value. The plastic scintillator showed ∼15 000 times higher light than that of water. Conclusions: Luminescence imaging during carbon-ion irradiation of water is not only possible but also a promising method for range estimation in carbon-ion therapy.

NK sensitivity of neuroblastoma cells determined by a highly sensitive coupled luminescent method

International Nuclear Information System (INIS)

Ogbomo, Henry; Hahn, Anke; Geiler, Janina; Michaelis, Martin; Doerr, Hans Wilhelm; Cinatl, Jindrich

2006-01-01

The measurement of natural killer (NK) cells toxicity against tumor or virus-infected cells especially in cases with small blood samples requires highly sensitive methods. Here, a coupled luminescent method (CLM) based on glyceraldehyde-3-phosphate dehydrogenase release from injured target cells was used to evaluate the cytotoxicity of interleukin-2 activated NK cells against neuroblastoma cell lines. In contrast to most other methods, CLM does not require the pretreatment of target cells with labeling substances which could be toxic or radioactive. The effective killing of tumor cells was achieved by low effector/target ratios ranging from 0.5:1 to 4:1. CLM provides highly sensitive, safe, and fast procedure for measurement of NK cell activity with small blood samples such as those obtained from pediatric patients

Terbium and dysprosium complexes luminescence at low temperatures

Energy Technology Data Exchange (ETDEWEB)

Meshkova, S B; Kravchenko, T B; Kononenko, L.I.; Poluehktov, N S [AN Ukrainskoj SSR, Odessa. Fiziko-Khimicheskij Inst.

1979-01-01

The variation is studied of the luminescence intensity of terbium and dysprosium complexes used in the analysis as solutions are cooled down to the liquid nitrogen temperature. Three groups of methods have been studied: observation of fluorescence of aqueous solutions, precipitate and extract suspensions in organic solvents. The brightest luminescence and greatest increase in luminescence intensity are observed at freezing of complex solvents with 1,2-dioxybenzene-3,5-disulfonic acid (DBSA) and iminodiacetic acid (IDA) and DBSA+EDTA, as well as in the case of benzene extracting of complexes with phenanthroline and salicylic acid. Otherwise the intensity increases 2-14-fold and for the complex of terbium with acetoacetic ester 36-fold.

Determination of U, Th and K for optically stimulated luminescence dating by NAA

International Nuclear Information System (INIS)

Qin Yali; Chen Zhe; Wu Weiming

2010-01-01

Optically stimulated luminescence dating techniques have been widely used in northern Loess ancient soil series and recorded climate environment change, ancient earthquake, the ancients site and archaeology research. The determination of U, Th and K using neutron activation analysis (NAA) has been optimized for the samples related to OSL dating research. The procedure for determination of U, Th, K in loess have been fixed by using Miniature neutron source reactor. This procedure of NAA will provide a reliable data base for optically stimulated luminescence dating research. (authors)

Luminescence from metals and insulators

International Nuclear Information System (INIS)

Crawford, O.H.

1985-01-01

The term luminescence is normally applied to light emission that is not explainable by the mechanisms discussed by the other speakers in this meeting. Specifically, it is not transition radiation, surface plasmon radiation, or bremsstrahlung. One normally thinks of luminescence as arising from one-electron transitions within a medium. This talk consists of an overview of luminescence from condensed matter under irradiation by either energetic particles or photons. The author begins with organic molecules, where luminescence is best understood, and then discusses inorganic insulators and metals. Finally, the dependence of yield upon projectile species and velocity is discussed, and predictions are made concerning the relative effectiveness of electrons, protons, and hydrogen atoms in exciting luminescence

Multi-millennial record of erosion and fires in the southern Blue Ridge Mountains, USA In: Greenberg, CH and BS Collins (eds.)

Science.gov (United States)

David S. Leigh

2016-01-01

Bottomland sediments from the southern Blue Ridge Mountains provide a coarse-resolution, multi-millennial stratigraphic record of past regional forest disturbance (soil erosion). This record is represented by 12 separate vertical accretion stratigraphic profi les that have been dated by radiocarbon, luminescence, cesium-137, and correlation methods...

A luminescent nisin biosensor

Science.gov (United States)

Immonen, Nina; Karp, Matti

2006-02-01

Nisin is a lantibiotic, an antibacterial peptide produced by certain Lactococcus lactis strains that kills or inhibits the growth of other bacteria. Nisin is widely used as a food preservative, and its long-time use suggests that it can be generally regarded as safe. We have developed a method for determining the amount of nisin in food samples that is based on luminescent biosensor bacteria. Bacterial luciferase operon luxABCDE was inserted into plasmid pNZ8048, and the construct was transformed by electroporation into Lc. lactis strain NZ9800, whose ability to produce nisin has been erased by deletion of the gene nisA. The operon luxABCDE has been modified to be functional in gram-positive bacteria to confer a bioluminescent phenotype without the requirement of adding an exogenous substrate. In the plasmid pNZ8048, the operon was placed under control of the nisin-inducible nisA promoter. The chromosomal nisRK genes of Lc. lactis NZ9800 allow it to sense nisin in the environment and relay this signal via signal transduction proteins NisK and NisR to initiate transcription from nisA promoter. In the case of our sensor bacteria, this leads to production of luciferase and, thus, luminescence that can be directly measured from living bacteria. Luminescence can be detected as early as within minutes of induction. The nisin assay described here provides a detection limit in the sub-picogram level per ml, and a linear area between 1 - 1000 pg/ml. The sensitivity of this assay exceeds the performance of all previously published methods.

Surface exposure dating of non-terrestrial bodies using optically stimulated luminescence: A new method

DEFF Research Database (Denmark)

Sohbati, Reza; Jain, Mayank; Murray, Andrew

2012-01-01

We propose a new method for in situ surface exposure dating of non-terrestrial geomorphological features using optically stimulated luminescence (OSL); our approach is based on the progressive emptying of trapped charge with exposure to light at depth into a mineral surface. A complete model of t...... charge population. The potential dating applications for (a) include dust accumulation, volcanic rocks and impact-related sediments, and for (b) fault scarps, rock-falls, landslides and ice-scoured bedrock. Using assumptions based on terrestrial observations we expect that this approach...

Luminescence recognition of different organophosphorus pesticides by the luminescent Eu(III)-pyridine-2,6-dicarboxylic acid probe

Energy Technology Data Exchange (ETDEWEB)

Azab, Hassan A., E-mail: azab2@yahoo.com [Chemistry Department, Faculty of Science, Suez Canal University, Ismailia 41522 (Egypt); Duerkop, Axel [Institute of Analytical Chemistry, Chemo and Biosensors, Regensburg University, D-93040 Regensburg (Germany); Anwar, Z.M.; Hussein, Belal H.M.; Rizk, Moustafa A.; Amin, Tarek [Chemistry Department, Faculty of Science, Suez Canal University, Ismailia 41522 (Egypt)

2013-01-08

Highlights: Black-Right-Pointing-Pointer Europium (III) luminescence quenching has been used for sensing organophosphorous pesticides. Black-Right-Pointing-Pointer Four guest pesticides chlorfenvinphos, malathion, azinphos, and paraxon ethyl were used. Black-Right-Pointing-Pointer A sensitive rapid, cheap direct method for the determination of the pesticides has been developed. Black-Right-Pointing-Pointer The method was applied to the determination of the OPs in tap, river, mineral, and waste waters. - Abstract: Luminescence quenching of a novel long lived Eu(III)-pyridine-2,6-dicarboxylic acid probe of 1:2 stoichiometric ratio has been studied in 0.10 volume fraction ethanol-water mixture at pH 7.5 (HEPES buffer) in the presence of the organophosphorus pesticides chlorfenvinphos (P1), malathion (P2), azinphos (P3), and paraxon ethyl (P4). The luminescence intensity of Eu(III)-(PDCA){sub 2} probe decreases as the concentration of the pesticide increases. It was observed that the quenching due to P3 and P4 proceeds via both diffusional and static quenching processes. Direct methods for the determination of the pesticides under investigation have been developed using the luminescence quenching of Eu(III)-pyridine-2,6-dicarboxylic acid probe in solution. The linear range for determination of the selected pesticides is 1.0-35.0 {mu}M. The detection limits were 0.24-0.55 {mu}M for P3, P4, and P1 and 2.5 {mu}M for P2, respectively. The binding constants (K), and thermodynamic parameters of the OPs with Eu(III)-(PDCA){sub 2} were evaluated. Positive and negative values of entropy ({Delta}S) and enthalpy ({Delta}H) changes for Eu(III)-(PDCA){sub 2}-P1 ternary complex were calculated. As the waters in this study do not contain the above mentioned OPs over the limit detectable by the method, a recovery study was carried out after the addition of the adequate amounts of the organophosphorus pesticides under investigation.

Feldspar, Infrared Stimulated Luminescence

DEFF Research Database (Denmark)

Jain, Mayank

2014-01-01

This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars.......This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars....

Construction of order mesoporous (Eu–La)/ZnO composite material and its luminescent characters

Energy Technology Data Exchange (ETDEWEB)

Bao, Na; Liu, Yu; Li, Zi-Wei [School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China); Yu, Hui, E-mail: yh2001101@163.com [School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China); Bai, Hao-tian [School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China); Xia, Long, E-mail: xialong_aron@163.com [School of Materials Science and Engineering, Harbin Institute of Technology at Weihai, Weihai 264209 (China); Feng, Da-wei [Changchun University of Science and Technology Science Park, Changchun 130022 (China); Guangdong College of Business and Technology, Zhaoqing 526020 (China); Zhang, Hong-bo; Dong, Xiang-ting; Wang, Tian-yang; Han, Ji; Wu, Rong-yi; Zhang, Qi [School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China)

2016-09-15

For the first time, the order mesoporous zinc oxide was synthesized by a soft template synthesis method. The Eu and La phosphate were introduced into the prepared mesoporous zinc oxide by the high temperature solid phase method, and got the mesoporous rare earth/zinc oxide composite materials. The luminescence characters of the materials were studied. The influences of La to Eu luminescent properties had been studied, and the optimum proportion of Eu and La was discussed. The influences of La and Eu to ZnO luminescence properties were also been studied. La phosphate had the large influence to Eu luminescent. ZnO had a strong emission peak at 469 nm, which overlapped with the {sup 7}F{sub 0}–{sup 5}D{sub 2} transition excitation peak of Eu at 465 nm. It indicated that the effective energy transfer happened between ZnO and Eu, which strongly enhanced the luminescence intensity of Eu. At the same time, the Eu and La phosphates could regulate the defect density of ZnO, which could regulate the luminescent intensity of ZnO, and realized the adjustment of luminescent color between green and red light.

First ever full size CdTE luminescent down-shifting module

NARCIS (Netherlands)

Ross, D.; Alonso-Alvarez, D.; Fritsche, J.; Bauer, M.; Debije, M.G.; Fifield, R.M.; Richards, B.S.

2012-01-01

For the first time a luminescent down-shifting (LDS) layer has been applied to a full size PV module to improve its short-wavelength response. An average 4.3% relative increase in the short-circuit current density (JSC) was recorded for the Calyxo cadmium telluride (CdTe) modules after the best LDS

Cerenkov luminescence tomography based on preconditioning orthogonal matching pursuit

Science.gov (United States)

Liu, Haixiao; Hu, Zhenhua; Wang, Kun; Tian, Jie; Yang, Xin

2015-03-01

Cerenkov luminescence imaging (CLI) is a novel optical imaging method and has been proved to be a potential substitute of the traditional radionuclide imaging such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT). This imaging method inherits the high sensitivity of nuclear medicine and low cost of optical molecular imaging. To obtain the depth information of the radioactive isotope, Cerenkov luminescence tomography (CLT) is established and the 3D distribution of the isotope is reconstructed. However, because of the strong absorption and scatter, the reconstruction of the CLT sources is always converted to an ill-posed linear system which is hard to be solved. In this work, the sparse nature of the light source was taken into account and the preconditioning orthogonal matching pursuit (POMP) method was established to effectively reduce the ill-posedness and obtain better reconstruction accuracy. To prove the accuracy and speed of this algorithm, a heterogeneous numerical phantom experiment and an in vivo mouse experiment were conducted. Both the simulation result and the mouse experiment showed that our reconstruction method can provide more accurate reconstruction result compared with the traditional Tikhonov regularization method and the ordinary orthogonal matching pursuit (OMP) method. Our reconstruction method will provide technical support for the biological application for Cerenkov luminescence.

Advantages and disadvantages of luminescence dosimetry

Energy Technology Data Exchange (ETDEWEB)

Olko, Pawel, E-mail: Pawel.Olko@ifj.edu.p [Institute of Nuclear Physics Polish Academy of Science (IFJ PAN), Krakow (Poland)

2010-03-15

Owing to their excellent dosimetric properties, luminescence detectors of ionizing radiation are now extensively applied in individual dosimetry services. The most frequently used personal dosemeters are based on Optically Stimulated Luminescence (OSL), radiophotoluminescence (RPL) or thermoluminescence (TL). Luminescence detectors have also found several applications in clinical dosimetry, especially around new radiation modalities in radiotherapy, such as Intensity Modulated Radiotherapy (IMRT) or ion beam radiotherapy. Requirements of luminescence detectors applied in individual and clinical dosimetry and some recent developments in luminescence of detectors and techniques leading to significant improvements of the functionality and accuracy of dosimetry systems are reviewed and discussed.

Appearance of high submerged cavitating jet: The cavitation phenomenon and sono luminescence

Directory of Open Access Journals (Sweden)

Hutli Ezddin

2013-01-01

Full Text Available In order to study jet structure and behaviour of cloud cavitation within time and space, visualization of highly submerged cavitating water jet has been done using Stanford Optics 4 Quick 05 equipment, through endoscopes and other lenses with Drello3244 and Strobex Flash Chadwick as flashlight stroboscope. This included obligatory synchronization with several types of techniques and lenses. Images of the flow regime have been taken, allowing calculation of the non-dimensional cavitation cloud length under working conditions. Consequently a certain correlation has been proposed. The influencing parameters, such as; injection pressure, downstream pressure and cavitation number were experimentally proved to be very significant. The recordings of sono-luminescence phenomenon proved the collapsing of bubbles everywhere along the jet trajectory. In addition, the effect of temperature on sono-luminescence recordings was also a point of investigation. [Projekat Ministarstva nauke Republike Srbije, br. TR35046

A new criterion of photostimulated luminescence (PSL) method to detect irradiated traditional Chinese medicinal herbs

International Nuclear Information System (INIS)

Zhang, Liwen; Lin, Tong; Jiang, Yingqiao; Bi, Fujun

2013-01-01

This work used a new criterion to analyze 162 varieties (222 batches) of traditional Chinese medicinal herbs based on the European Standard EN 13751 (2009. Foodstuffs—Detection of Irradiated Food Using Photostimulated Luminescence. European Committee for Standardization, Brussels, Belgium). The characteristics of PSL signals are described, and a new criterion is established. Compared to EN 13751, the new criterion uses clearer definition to evaluate instead of the ambiguous descriptions in EN Standard, such as “much greater than” and “within the same order of magnitude”. Moreover, the accuracy of the new criterion is as good as or better than EN Standard in regard to classifying irradiated and non-irradiated traditional Chinese medicinal herbs. It can help to avoid false positive result when a non-irradiated herb got a screening PSL measurement above 5000 counts/60 s. This new criterion of photostimulated luminescence method can be applied to identify the irradiation status of traditional Chinese medicinal herbs, even if the medicinal herbs were irradiated at a low dose (0.3 kGy) or stored in the dark at room temperature for 24 months after the irradiation treatment. - Highlights: • Clearer evaluation criterion instead of the ambiguous descriptions in EN 13751. • Accuracy satisfied. • Large sample size provides outstanding representativeness. • Systematical evaluation on PSL method

High-resolution stratigraphy and multiple luminescence dating techniques to reveal the paleoseismic history of the central Dead Sea fault (Yammouneh fault, Lebanon)

Science.gov (United States)

Le Béon, Maryline; Tseng, Ya-Chu; Klinger, Yann; Elias, Ata; Kunz, Alexander; Sursock, Alexandre; Daëron, Mathieu; Tapponnier, Paul; Jomaa, Rachid

2018-07-01

Continuous sedimentation and detailed stratigraphy are key parameters for a complete paleo-earthquake record. Here, we present a new paleoseismological study across the main strike-slip fault branch of the Dead Sea fault in Lebanon. We aim to expand the current knowledge on local paleoseismicity and seismic behavior of strike-slip plate boundary faults and to explore the limitations of paleoseismology and dating methods. The trench, dug in the Jbab el-Homr basin, reveals a succession of remarkable, very thin (0.1 to 5 cm) palustrine and lacustrine layers, ruptured by at least 17 earthquakes. Absolute ages of 4 samples are obtained from three luminescence-dating techniques targeting fine-grain minerals. Blue-green stimulated luminescence (BGSL) on quartz and post-infrared infrared-stimulated luminescence at 225 °C on polymineral aliquots led to consistent ages, while ages from infrared-stimulated luminescence at 50 °C on polymineral aliquots appeared underestimated. The quartz BGSL ages are 26.9 ± 2.3 ka at 0.50 m depth and 30.8 ± 2.9 ka at 3.65 m depth. During this time period of 3.9 ka ([0; 9.1 ka]), 14 surface-rupturing events occurred with a mean return time of 280 years ([0; 650 years]) and probable clustering. This return time is much shorter than the 1127 ± 135 years return time previously determined at the Yammouneh site, located 30 km south. Although fault segmentation and temporal variations in the earthquake cycle remain possible causes for such different records, we argue that the high-resolution stratigraphy in Jbab is the main factor, enabling us to record small deformations related to smaller-magnitude events that may have been missed in the rougher strata of Yammouneh. Indeed, focusing only on larger events of Jbab, we obtain a mean return time of 720 years ([0; 1670 years]) that is compatible with the Yammouneh record.

Luminescence lifetimes in natural quartz annealed beyond its second phase inversion temperature

International Nuclear Information System (INIS)

Chithambo, M.L.

2015-01-01

The influence of annealing, irradiation dose, preheating and measurement temperature on luminescence lifetimes has been studied in quartz annealed at 1000 °C. The measurements were supplemented by studies on quartz annealed at 900 and 800 °C. Lifetimes increase with dose as well as with temperature and duration of annealing between 800 and 1000 °C. Preheating produces the same effect. The changes are accounted for in terms of hole-transfer from the non-radiative luminescence centre to and between radiative centres. The influence of measurement temperature on lifetimes depends on whether the stimulation is carried out from ambient to 200 °C or otherwise. This result is unlike that in quartz annealed at or below 500 °C where lifetimes are independent of the direction of heating. In particular, lifetimes decrease monotonically when measurements are made from 20 to 200 °C but not when recorded from 200 to 20 °C. The latter produces a pattern resembling that in quartz annealed up to 500 °C. The results are concluded as evidence of thermal effects on separate luminescence centres. In support of this, different values of the activation energy for thermal quenching were found for each supposed luminescence centre. The change of the corresponding luminescence intensity with temperature is also qualitatively consistent with this notion. - Highlights: • Luminescence lifetimes in natural quartz annealed beyond its second phase inversion temperature is reported. • Lifetimes increase with dose, annealing between 800 and 1000 °C, and preheating. • Lifetimes under stimulation temperature are affected by direction of heating. • Changes are accounted for in terms of hole-transfer luminescence centres.

Luminescence recognition of different organophosphorus pesticides by the luminescent Eu(III)–pyridine-2,6-dicarboxylic acid probe

International Nuclear Information System (INIS)

Azab, Hassan A.; Duerkop, Axel; Anwar, Z.M.; Hussein, Belal H.M.; Rizk, Moustafa A.; Amin, Tarek

2013-01-01

Highlights: ► Europium (III) luminescence quenching has been used for sensing organophosphorous pesticides. ► Four guest pesticides chlorfenvinphos, malathion, azinphos, and paraxon ethyl were used. ► A sensitive rapid, cheap direct method for the determination of the pesticides has been developed. ► The method was applied to the determination of the OPs in tap, river, mineral, and waste waters. - Abstract: Luminescence quenching of a novel long lived Eu(III)–pyridine-2,6-dicarboxylic acid probe of 1:2 stoichiometric ratio has been studied in 0.10 volume fraction ethanol–water mixture at pH 7.5 (HEPES buffer) in the presence of the organophosphorus pesticides chlorfenvinphos (P1), malathion (P2), azinphos (P3), and paraxon ethyl (P4). The luminescence intensity of Eu(III)–(PDCA) 2 probe decreases as the concentration of the pesticide increases. It was observed that the quenching due to P3 and P4 proceeds via both diffusional and static quenching processes. Direct methods for the determination of the pesticides under investigation have been developed using the luminescence quenching of Eu(III)–pyridine-2,6-dicarboxylic acid probe in solution. The linear range for determination of the selected pesticides is 1.0–35.0 μM. The detection limits were 0.24–0.55 μM for P3, P4, and P1 and 2.5 μM for P2, respectively. The binding constants (K), and thermodynamic parameters of the OPs with Eu(III)–(PDCA) 2 were evaluated. Positive and negative values of entropy (ΔS) and enthalpy (ΔH) changes for Eu(III)–(PDCA) 2 –P1 ternary complex were calculated. As the waters in this study do not contain the above mentioned OPs over the limit detectable by the method, a recovery study was carried out after the addition of the adequate amounts of the organophosphorus pesticides under investigation.

On the half-life of luminescence signals in dosimetric applications: A unified presentation

Science.gov (United States)

Pagonis, V.; Kitis, G.; Polymeris, G. S.

2018-06-01

Luminescence signals from natural and man-made materials are widely used in dosimetric and dating applications. In general, there are two types of half-lives of luminescence signals which are of importance to experimental and modeling work in this research area. The first type of half-life is the time required for the population of the trapped charge in a single trap to decay to half its initial value. The second type of half-life is the time required for the luminescence intensity to drop to half of its initial value. While there a handful of analytical expressions available in the literature for the first type of half-life, there are no corresponding analytical expressions for the second type. In this work new analytical expressions are derived for the half-life of luminescence signals during continuous wave optical stimulation luminescence (CW-OSL) or isothermal luminescence (ITL) experiments. The analytical expressions are derived for several commonly used luminescence models which are based on delocalized transitions involving the conduction band: first and second order kinetics, empirical general order kinetics (GOK), mixed order kinetics (MOK) and the one-trap one-recombination center (OTOR) model. In addition, half-life expressions are derived for a different type of luminescence model, which is based on localized transitions in a random distribution of charges. The new half-life expressions contain two parts. The first part is inversely proportional to the thermal or optical excitation rate, and depends on the experimental conditions and on the cross section of the relevant luminescence process. The second part is characteristic of the optical and/or thermal properties of the material, as expressed by the parameters in the model. A new simple and quick method for analyzing luminescence signals is developed, and examples are given of applying the new method to a variety of dosimetric materials. The new test allows quick determination of whether a set of

Preparation, characterization and luminescence of nanocrystalline Y2O3:Ho

International Nuclear Information System (INIS)

Biljan, Tomislav; Gajovic, Andreja; Meic, Zlatko; Mestrovic, Ernest

2007-01-01

Nanocrystalline Y 2 O 3 :Ho was synthesized by solution combustion method with ethylene glycol as fuel. Material was characterized using powder X-ray diffraction and transmission electron microscopy (TEM). X-ray diffraction and TEM showed that the material is nanostructured. Luminescence properties were studied using Raman spectrometers with excitation in near infrared (NIR) and visible regions. The visible and NIR luminescence spectra of nanocrystalline Y 2 O 3 :Ho show some important differences from those of bulk material. The convenience of using Raman instruments for studying luminescence of lanthanide ions is demonstrated

Effect of solution composition on determination of uranium (6) microquantities by laser-induced luminescence method

International Nuclear Information System (INIS)

Romanovskaya, G.I.; Zakharova, G.V.; Chibisova, A.K.

1984-01-01

The effect of cation and anion composition of natural waters (sea water, ground water, etc.) on the uranium (6) determination in the form of uranyl complexes with Na 2 O3SiO 2 using the laser-induced luminescence method with the determination limit 2x10 -11 g/ml, has been studied. The dependence of the luminescence intensity of uranyl polysilicate complexes on the inorganic ion concentration has been measured. The measurement results permitted to determine the maximum permissible concentrations (MAC) of ions, the values of which are presented. The results reproducibility is characterized by a relative standard deveation within 0.01-0.05. It follows from the data analysis that the MPC of impurities vary from 10 -8 to 10 -2 g/ml. The MPCs of uranium as determined in the form of polysilicate complexes, are shown to be close to the values obtained during uranium determination in the form of complexes with fluoran for the CO 3 2- , Ni, Cu ions and they are by an order higher for the Na, K, Cl - , SO 4 2- , HPO 4 2- , Mn ions

Blue-green luminescent CdZnSeS nanocrystals synthesized with activated alkyl thiol

International Nuclear Information System (INIS)

Xia Xing; Liu Zuli; Du Guihuan; Li Yuebin; Ma Ming; Yao Kailun

2012-01-01

Semiconductor nanocrystals with blue-green luminescence are potentially useful in various applications, but the preparation has not been easy compared to regular semiconductor nanocrystals with emission in the orange-red range. In this research alloyed CdZnSeS nanocrystals with luminescence covering the wavelength range from 430 to 560 nm are obtained by a one-step method with the assistance of alkyl thiol compound 1-dodecanethiol, which serves both as the sulfur source and surface ligand. The luminescence of CdZnSeS nanocrystals can be tuned from blue to green by altering the Cd:Zn molar ratio. Besides, the amount of 1-dodecanethiol in the reaction mixture can influence the emission wavelength by restricting the growth of nanocrystals. The dual control of both particle composition and size has enabled the tuning of luminescence to cover the blue-green spectral window. This research presents a convenient method to synthesize nanocrystals with tunable blue-green emission; these materials can be useful in advanced technologies such as photovoltaics, lighting and display. - Highlights: → Obtained blue-green luminescent nanocrystals by a one-step process. → Alkyl thiol used as a sulfur source and a surface stabilizer to control particle size. → Luminescence color of NCs could be easily tuned by changing their composition and particle size simultaneously.

New polymers containing BF2-benzoylacetonate groups. Synthesis, luminescence, excimer and exciplex formation

International Nuclear Information System (INIS)

Fedorenko, Elena V.; Mirochnik, Anatolii G.; Beloliptsev, Anton Yu.

2017-01-01

In the present study, a new synthetic method for the functionalization of polystyrene (PS) and (styrene-methyl methacrylate) copolymer has been developed. Using the new method, polymers containing BF 2 -benzoylacetonate groups have been obtained through double acylation by acetic anhydride with boron trifluoride. Luminescence of the produced polymers in solutions and films has been studied. Quantum yields of polymer solution luminescence are significantly higher than those of the low-molecular-weight analog – boron difluoride benzoylacetonate. For the polymer, in which styrene fragments are separated by methyl methacrylate groups, at low concentrations of the polymer in solution one observes the monomer luminescence of BF 2 -benzoylacetonate groups, while at high concentrations – the excimer luminescence. In case of PS-based polymers, in which BF 2 -benzoylacetonate groups and phenyl rings are not separated, in diluted solutions one observes the fluorescence of the intramolecular exciplexes, while at the concentration increase – the luminescence of intermolecular exciplexes. The ability of excimer formation is responsible for the increased photostability of the produced polymers. - Highlights: •Polymers containing BF 2 -benzoylacetonate groups have been synthesized. •Luminescence of the produced polymers in solutions and films has been studied. •Formation of excimers and exciplexes in solution has been revealed. •Formation of excimers in films increases their photostability.

New luminescence measurement facilities in retrospective dosimetry

DEFF Research Database (Denmark)

Lapp, Torben; Jain, Mayank; Thomsen, Kristina Jørkov

2012-01-01

), this facility has been used to measure natural doses in feldspar using the decaying NIR RL signal.Secondly, we present a method for mapping radiation field of the built-in 90Sr/90Y β-source and estimating grain-location specific dose-rates. This is important for the accuracy of single grain results, when......This paper gives a review of recent developments in luminescence measurement facilities on the Risø TL/OSL reader including radio-luminescence (RL), exo-electron and violet stimulation attachments, and a method for characterising and if necessary correcting for beta irradiation source non...... radiation field is spatially non-uniform across the sample area. We document the effect of this correction method and further investigate on the effect of lifting the source to achieve a better dose-rate uniformity.Finally we summarise two recently-developed novel facilities to help investigate (i) the time...

The extended Beer-Lambert theory for ray tracing modeling of LED chip-scaled packaging application with multiple luminescence materials

Science.gov (United States)

Yuan, Cadmus C. A.

2015-12-01

Optical ray tracing modeling applied Beer-Lambert method in the single luminescence material system to model the white light pattern from blue LED light source. This paper extends such algorithm to a mixed multiple luminescence material system by introducing the equivalent excitation and emission spectrum of individual luminescence materials. The quantum efficiency numbers of individual material and self-absorption of the multiple luminescence material system are considered as well. By this combination, researchers are able to model the luminescence characteristics of LED chip-scaled packaging (CSP), which provides simple process steps and the freedom of the luminescence material geometrical dimension. The method will be first validated by the experimental results. Afterward, a further parametric investigation has been then conducted.

Luminescence due to peptide linkage observed in L-cysteine molecules irradiated by infrared laser light

Energy Technology Data Exchange (ETDEWEB)

Tsujibayashi, Toru, E-mail: toru-t@cc.osaka-dent.ac.jp [Department of Physics, Osaka Dental University, 8-1 Kuzuha-hanazono, Hirakata, Osaka 573-1121 (Japan); Matsubara, Eiichi; Ichimiya, Masayoshi [Department of Physics, Osaka Dental University, 8-1 Kuzuha-hanazono, Hirakata, Osaka 573-1121 (Japan); Ohno, Nobuhito [Fundamental Electronics Research Institute, Osaka Electro-Communication University, 18-8 Hatsu-Cho, Neyagawa, Osaka 572-8530 (Japan)

2016-01-15

The sequence of amino acids in peptide chains consisting of proteins is the most fundamental information of living things. A direct and nondestructive method of reading is highly required as an alternative to the method based on the gene analysis. Luminescence detection is a very sensitive tool for investigating various materials. In order to find characteristic luminescence of each amino acid we study L-cysteine and L-tyrosine using UV laser of 3.36 eV with pulse duration of 1.5 ps. In addition to a common 2.66 eV band of the luminescence we have found 2.89 eV band for L-cysteine and 2.92 eV band for L-tyrosine. It can be interpreted that the side chain makes difference on the luminescence by affecting the peptide linkage or carbonyl group. - Highlights: • Luminescence from L-cysteine and L-tyrosine are studied. • Analyzing the luminescence enables to distinguish those two amino acids. • The lifetimes and the peak photon energies under UV laser excitation are presented.

Metal plasmon enhanced europium complex luminescence

International Nuclear Information System (INIS)

Liu Feng; Aldea, Gabriela; Nunzi, Jean-Michel

2010-01-01

The plasmon enhanced luminescence of a rare-earth complex Tris(6, 6, 7, 7, 8, 8, 8-heptafluoro-2, 2-dimethyl-3, 5-octanedionato) europium (Eu(fod) 3 ) was investigated. A polyvinyl alcohol (PVA) thin film was successfully adopted as a spacer to separate the Eu complex from the silver island film (SIF), and five-fold enhancement of the radiative decay rate of the Eu complex on SIF was demonstrated based on the luminescence intensity and lifetime measurement. Investigation of the distance dependent luminescence indicates that 7 nm is an optimal distance for SIF enhanced Eu luminescence. Plasmon enhanced rare-earth luminescence based on an organic film spacer would find potential applications in plasmon enhanced organic light emitting diode (OLED) devices.

Evaluation of one-step luminescent cyanoacrylate fuming.

Science.gov (United States)

Khuu, Alicia; Chadwick, Scott; Spindler, Xanthe; Lam, Rolanda; Moret, Sébastien; Roux, Claude

2016-06-01

One-step luminescent cyanoacrylates have recently been introduced as an alternative to the conventional cyanoacrylate fuming methods. These new techniques do not require the application of a luminescent post-treatment in order to enhance cyanoacrylate-developed fingermarks. In this study, three one-step polymer cyanoacrylates: CN Yellow Crystals (Aneval Inc.), PolyCyano UV (Foster+Freeman Ltd.) and PECA Multiband (BVDA), and one monomer cyanoacrylate: Lumikit™ (Crime Scene Technology), were evaluated against a conventional two-step cyanoacrylate fuming method (Cyanobloom (Foster+Freeman Ltd.) with rhodamine 6G stain). The manufacturers' recommended conditions or conditions compatible with the MVC™ 1000/D (Foster+Freeman Ltd.) were assessed with fingermarks aged for up to 8 weeks on non-porous and semi-porous substrates. Under white light, Cyanobloom generally gave better development than the one-step treatments across the substrates. Similarly when viewed under the respective luminescent conditions, Cyanobloom with rhodamine 6G stain resulted in improved contrast against the one-step treatments except on polystyrene, where PolyCyano UV and PECA Multiband gave better visualisation. Rhodamine 6G post-treatment of one-step samples did not significantly enhance the contrast of any of the one-step treatments against Cyanobloom/rhodamine 6G-treated samples. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Investigation into scanning tunnelling luminescence microscopy

International Nuclear Information System (INIS)

Manson-Smith, S.K.

2001-01-01

This work reports on the development of a scanning tunnelling luminescence (STL) microscope and its application to the study of Ill-nitride semiconductor materials used in the production of light emitting devices. STL microscopy is a technique which uses the high resolution topographic imaging capabilities of the scanning tunnelling microscope (STM) to generate high resolution luminescence images. The STM tunnelling current acts as a highly localised source of electrons (or holes) which generates luminescence in certain materials. Light generated at the STM tunnelling junction is collected concurrently with the height variation of the tunnelling probe as it is scanned across a sample surface, producing simultaneous topographic and luminescence images. Due to the very localised excitation source, high resolution luminescence images can be obtained. Spectroscopic resolution can be obtained by using filters. Additionally, the variation of luminescence intensity with tunnel current and with bias voltage can provide information on recombination processes and material properties. The design and construction of a scanning tunnelling luminescence microscope is described in detail. Operating under ambient conditions, the microscope has several novel features, including a new type of miniature inertial slider-based approach motor, large solid-angle light collection optical arrangement and a tip-height regulation system which requires the minimum of operator input. (author)

Polymeric Luminescent Compositions Doped with Beta-Diketonates Boron Difluoride as Material for Luminescent Solar Concentrator

Science.gov (United States)

Khrebtov, A. A.; Fedorenko, E. V.; Reutov, V. A.

2017-11-01

In this paper we investigated polymeric luminescent compositions based on polystyrene doped with beta diketonates boron difluoride. Transparent films with effective absorption in the ultraviolet and blue regions of the spectrum were obtained. Polymeric luminescent compositions based on the mixture of dyes allow expanding the absorption region and increase the radiation shift. A luminescent solar concentrator consisting of a glass plate coated with such film can be used for photovoltaic window application.

Synthesis of porous silicon nano-wires and the emission of red luminescence

International Nuclear Information System (INIS)

Congli, Sun; Hao, Hu; Huanhuan, Feng; Jingjing, Xu; Yu, Chen; Yong, Jin; Zhifeng, Jiao; Xiaosong, Sun

2013-01-01

This very paper is focusing on the characterization of porous silicon nano-wires prepared via a two-step route, the electroless chemical etching and the following post-treatment of HF/HNO 3 solution. Hence, scanning electron microscopy, transmission electron microscopy and confocal fluorescence microscopy are employed for this purpose. From the results of experiments, one can find that the as-prepared silicon nano-wire is of smooth surface and that no visible photo-luminescence emission could be seen. However, the porous structure can be found in the silicon nano-wire treated with HF/HNO 3 solution, and the clear photo-luminescence emission of 630 nm can be recorded with a confocal fluorescence microscope. The transmission electron microscopy test tells that the porous silicon nano-wire is made up of a porous crystalline silicon nano-core and a rough coating of silicon oxide. Besides, based on the post-HF- and -H 2 O 2 - treatments, the emission mechanism of the red luminescence has been discussed and could be attributed to the quantum confinement/luminescence center model which could be simply concluded as that the electron–hole pairs are mainly excited inside the porous silicon nano-core and then tunneling out and recombining at the silicon oxide coating.

Synthesis of porous silicon nano-wires and the emission of red luminescence

Energy Technology Data Exchange (ETDEWEB)

Congli, Sun [School of Materials Science and Engineering, Sichuan University (China); Hao, Hu [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, Sichuan (China); Huanhuan, Feng; Jingjing, Xu; Yu, Chen; Yong, Jin; Zhifeng, Jiao [School of Materials Science and Engineering, Sichuan University (China); Xiaosong, Sun, E-mail: sunxs@scu.edu.cn [School of Materials Science and Engineering, Sichuan University (China)

2013-10-01

This very paper is focusing on the characterization of porous silicon nano-wires prepared via a two-step route, the electroless chemical etching and the following post-treatment of HF/HNO{sub 3} solution. Hence, scanning electron microscopy, transmission electron microscopy and confocal fluorescence microscopy are employed for this purpose. From the results of experiments, one can find that the as-prepared silicon nano-wire is of smooth surface and that no visible photo-luminescence emission could be seen. However, the porous structure can be found in the silicon nano-wire treated with HF/HNO{sub 3} solution, and the clear photo-luminescence emission of 630 nm can be recorded with a confocal fluorescence microscope. The transmission electron microscopy test tells that the porous silicon nano-wire is made up of a porous crystalline silicon nano-core and a rough coating of silicon oxide. Besides, based on the post-HF- and -H{sub 2}O{sub 2}- treatments, the emission mechanism of the red luminescence has been discussed and could be attributed to the quantum confinement/luminescence center model which could be simply concluded as that the electron–hole pairs are mainly excited inside the porous silicon nano-core and then tunneling out and recombining at the silicon oxide coating.

A sprayable luminescent pH sensor and its use for wound imaging in vivo.

Science.gov (United States)

Schreml, Stephan; Meier, Robert J; Weiß, Katharina T; Cattani, Julia; Flittner, Dagmar; Gehmert, Sebastian; Wolfbeis, Otto S; Landthaler, Michael; Babilas, Philipp

2012-12-01

Non-invasive luminescence imaging is of great interest for studying biological parameters in wound healing, tumors and other biomedical fields. Recently, we developed the first method for 2D luminescence imaging of pH in vivo on humans, and a novel method for one-stop-shop visualization of oxygen and pH using the RGB read-out of digital cameras. Both methods make use of semitransparent sensor foils. Here, we describe a sprayable ratiometric luminescent pH sensor, which combines properties of both these methods. Additionally, a major advantage is that the sensor spray is applicable to very uneven tissue surfaces due to its consistency. A digital RGB image of the spray on tissue is taken. The signal of the pH indicator (fluorescein isothiocyanate) is stored in the green channel (G), while that of the reference dye [ruthenium(II)-tris-(4,7-diphenyl-1,10-phenanthroline)] is stored in the red channel (R). Images are processed by rationing luminescence intensities (G/R) to result in pseudocolor pH maps of tissues, e.g. wounds. © 2012 John Wiley & Sons A/S.

Luminescence sensitivity changes in quartz

CERN Document Server

Wintle, A G

1999-01-01

In the luminescence dating of sedimentary or heated quartz, some heat treatment is usually applied to the sample immediately prior to the measurement of the optically stimulated luminescence. In this paper we report experiments on a 30,000-year-old sedimentary quartz, in which we use the luminescence response to a test dose to monitor the changes in sensitivity that are caused by holding the quartz at temperatures from 160 to 280 deg. C for times from 10 s to 22 h. For an optically bleached sample, the monitoring is by both optically stimulated luminescence and the 110 deg. C TL peak; both luminescence signals are shown to have the same sensitisation (i.e. activation energy) characteristics. For natural or laboratory irradiated samples only the 110 deg. C TL peak can be used; sensitivity increases of up to a factor of 1.3 and 3 are observed for the natural and laboratory irradiated aliquots, respectively. Up to four exponential components are used to deconvolve the sensitivity change data; the dominant compon...

Luminescence in medical image science

Energy Technology Data Exchange (ETDEWEB)

Kandarakis, I.S., E-mail: kandarakis@teiath.gr

2016-01-15

Radiation detection in Medical Imaging is mostly based on the use of luminescent materials (scintillators and phosphors) coupled to optical sensors. Materials are employed in the form of granular screens, structured (needle-like) crystals and single crystal transparent blocks. Storage phosphors are also incorporated in some x-ray imaging plates. Description of detector performance is currently based on quality metrics, such as the Luminescence efficiency, the Modulation Transfer Function (MTF), the Noise Power Spectrum (NPS) and the Detective Quantum Efficiency (DQE) can be defined and evaluated. The aforementioned metrics are experimental evaluated for various materials in the form of screens. A software was designed (MINORE v1) to present image quality measurements in a graphical user interface (GUI) environment. Luminescence efficiency, signal and noise analysis are valuable tools for the evaluation of luminescent materials as candidates for medical imaging detectors. - Highlights: • Luminescence based medical imaging detectors. • Image science: MTF, NPS, DQE. • Phosphors screens light emission efficiency experimental evaluation. • Theoretical models for estimation of phosphor screen properties. • Software for medical image quality metrics.

Porous glasses as a host of luminescent materials, their applications and site selective determination

Energy Technology Data Exchange (ETDEWEB)

Reisfeld, Renata, E-mail: renata.reisfeld@mail.huji.ac.il [Institute of Chemistry, Hebrew University of Jerusalem, Givat-Ram, Jerusalem 91904 (Israel); Jasinska, Bozena [Institute of Physics, Maria Curie-Sklodowska University, Pl. M. Curie-Skłodowsskiej 1, 20-031 Lublin (Poland); Levchenko, Viktoria [Institute of Chemistry, Hebrew University of Jerusalem, Givat-Ram, Jerusalem 91904 (Israel); Gorgol, Marek [Institute of Physics, Maria Curie-Sklodowska University, Pl. M. Curie-Skłodowsskiej 1, 20-031 Lublin (Poland); Saraidarov, Tsiala; Popov, Inna [Institute of Chemistry, Hebrew University of Jerusalem, Givat-Ram, Jerusalem 91904 (Israel); Antropova, Tatiana [I. V. Grebenshchikov Institute of the Chemistry of Silicates, Russian Academy of Sciences, Nab. Makarova, 2, Liter B, Saint-Petersburg 199034 (Russian Federation); Rysiakiewicz-Pasek, Ewa [Institute of Physics, Wroclaw University of Technology, W. Wyspianskiego 27, 50-370 Wroclaw (Poland)

2016-01-15

The site selective distribution of pore sizes in pure porous glasses and glasses doped by a luminescent colorant is determined by luminescent spectroscopy, SEM, SAXS and PALS. The potential applications of the studied materials as environmental and biological sensors are outlined. We suggest how luminescent porous glasses doped by complexes of Gd can act as solid scintillators in tracing elementary particles like neutrino. - Highlights: • Porous glasses are a medium for large number of luminescent materials. • Size distribution of empty and filled pores is studied. • The validity of data obtained by different methods is analyzed.

Kinetic study of Tb/sup 3 +/(/sup 5/D/sub 3/) luminescence in phosphate glasses

Energy Technology Data Exchange (ETDEWEB)

Anisimov, V.A.; Dmitryuk, A.V.; Karapetyan, G.O.

1986-01-01

This paper presents precise determinations of the kinetics of terbium luminescence over a broad dynamic range, in order to refine the mechanism of concentration quenching of the Tb/sup 3 +/(/sup 5/D/sub 3/) luminescence in glasses. After establishing the mechanism of Tb/sup 3 +/(/sup 5/D/sub 3/) luminescence quenching by the iteration method, the authors determine the value of the parameter for an arbitrary concentration of the activator. Results of this study show that the mechanism of concentration quenching of luminescence is static dipole-dipole interaction of terbium ions.

The effect of thermal oxidation on the luminescence properties of nanostructured silicon.

Science.gov (United States)

Liu, Lijia; Sham, Tsun-Kong

2012-08-06

Herein is reported a detailed study of the luminescence properties of nanostructured Si using X-ray excited optical luminescence (XEOL) in combination with X-ray absorption near-edge structures (XANES). P-type Si nanowires synthesized via electroless chemical etching from Si wafers of different doping levels and porous Si synthesized using electrochemical method are examined under X-ray excitation across the Si K-, L(3,2) -, and O K-edges. It is found that while as-prepared Si nanostructures are weak light emitters, intense visible luminescence is observed from thermally oxidized Si nanowires and porous Si. The luminescence mechanism of Si upon oxidation is investigated by oxidizing nanostructured Si at different temperatures. Interestingly, the two luminescence bands observed show different response with the variation of absorption coefficient upon Si and O core-electron excitation in elemental silicon and silicon oxide. A correlation between luminescence properties and electronic structures is thus established. The implications of the finding are discussed in terms of the behavior of the oxygen deficient center (OCD) and non-bridging oxygen hole center (NBOHC). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Novel and easy access to highly luminescent Eu and Tb doped ultra-small CaF2, SrF2 and BaF2 nanoparticles - structure and luminescence.

Science.gov (United States)

Ritter, Benjamin; Haida, Philipp; Fink, Friedrich; Krahl, Thoralf; Gawlitza, Kornelia; Rurack, Knut; Scholz, Gudrun; Kemnitz, Erhard

2017-02-28

A universal fast and easy access at room temperature to transparent sols of nanoscopic Eu 3+ and Tb 3+ doped CaF 2 , SrF 2 and BaF 2 particles via the fluorolytic sol-gel synthesis route is presented. Monodisperse quasi-spherical nanoparticles with sizes of 3-20 nm are obtained with up to 40% rare earth doping showing red or green luminescence. In the beginning luminescence quenching effects are only observed for the highest content, which demonstrates the unique and outstanding properties of these materials. From CaF 2 :Eu10 via SrF 2 :Eu10 to BaF 2 :Eu10 a steady increase of the luminescence intensity and lifetime occurs by a factor of ≈2; the photoluminescence quantum yield increases by 29 to 35% due to the lower phonon energy of the matrix. The fast formation process of the particles within fractions of seconds is clearly visualized by exploiting appropriate luminescence processes during the synthesis. Multiply doped particles are also available by this method. Fine tuning of the luminescence properties is achieved by variation of the Ca-to-Sr ratio. Co-doping with Ce 3+ and Tb 3+ results in a huge increase (>50 times) of the green luminescence intensity due to energy transfer Ce 3+ → Tb 3+ . In this case, the luminescence intensity is higher for CaF 2 than for SrF 2 , due to a lower spatial distance of the rare earth ions.

Luminescence enhancement of ZnO-poly(methylmethacrylate) nanocomposite films by incorporation of crystalline BaTiO_3 nanoparticles

International Nuclear Information System (INIS)

Kanamori, Tsuyoshi; Han, Yu; Nagao, Daisuke; Kamezawa, Nao; Ishii, Haruyuki; Konno, Mikio

2016-01-01

Highlights: • Dielectric barium titanate (BT) nanoparticles incorporated into luminescence films. • Luminescence intensities increased by the BT nanoparticle incorporation. • Incorporation of highly dielectric nanoparticles effective for luminescence enhancement. - Abstract: Incorporation of highly dielectric nanoparticles into luminescent ZnO-polymethylmethacrylate (PMMA) nanocomposite films was undertaken to examine the effect of nanoparticle incorporation on luminescence intensity of the nanocomposite films. ZnO nanoparticles were prepared as inorganic phosphors by a precipitation method. The ZnO nanoparticles were then surface-modified with 3-methacryloxypropyltrimethoxysilane (MPTMS) to be used for fabrication of the ZnO-PMMA nanocomposite film. Barium titanate (BT) nanoparticles were synthesized with a sol-gel method as the highly dielectric nanoparticles, which were also surface-modified with the MPTMS for the incorporation into the nanocomposite films. Luminescence intensity of the nanocomposite films was successfully increased by the nanoparticle incorporation up to a BT content around 15 vol%. The luminescence intensity higher than that measured for the nanocomposite films incorporating SiO_2 nanoparticles indicated that the incorporation of highly dielectric nanoparticles was an effective approach to enhance the luminescence of ZnO nanoparticles in the polymer thin films.

Ab initio calculations of cross luminescence materials

International Nuclear Information System (INIS)

Kanchana, V.

2016-01-01

Abintio calculations have been performed to study the structural, electronic, and optical properties of ABX 3 (A=alkali, B=alkaline-earth, and X=halide) compounds. The ground state properties are calculated using the pseudopotential method with the inclusion of van der Waals interaction, which we find inevitable in reproducing the experimental structure properties in alkali iodides because of its layered structure. All calculations were performed using the Full-Potential Linearized Augmented Plane Wave method. The band structures are plotted with various functionals and we find the newly developed Tran and Blaha modified Becke-Johnson potential to improve the band gap significantly. The optical properties such as complex dielectric function, refractive index, and absorption spectra are calculated which clearly reveal the optically isotropic nature of these materials though being structurally anisotropic, which is the key requirement for ceramic scintillators. Cross luminescence materials are very interesting because of its fast decay. One of the major criteria for the cross luminescence to happen is the energy difference between valence band and next deeper core valence band being lesser when compared to energy gap of the compound, so that radiative electronic transition may occur between valence band and core valence band. We found this criteria to be satisfied in all the studied compounds leading to cross luminescence except for KSrI 3 , RbSrI 3 . The present study suggest that among the six compounds studied, CsSrI 3 , CsMgCl 3 , CsCaCl 3 , and CsSrCl 3 compounds are cross luminescence materials, which is well explained from the band structure, optical properties calculations. Chlorides are better scintillators that iodides and CsMgCl 3 is found to be promising one among the studied compounds. Apart from these materials we have also discussed electronic structure and optical properties of other scintillator compounds. (author)

Luminescence from Ce in sol-gel SiO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Kroon, R.E., E-mail: KroonRE@ufs.ac.za [Department of Physics, University of the Free State, IB51, Box 339, Bloemfontein 9300 (South Africa); Seed Ahmed, H.A.A.; Ntwaeaborwa, O.M. [Department of Physics, University of the Free State, IB51, Box 339, Bloemfontein 9300 (South Africa); Koao, L.F. [Department of Physics, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa); Nagpure, I.M.; Gusowski, M.A. [Department of Physics, University of the Free State, IB51, Box 339, Bloemfontein 9300 (South Africa); Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, Box 77000, Port Elizabeth 6031 (South Africa); Swart, H.C. [Department of Physics, University of the Free State, IB51, Box 339, Bloemfontein 9300 (South Africa)

2012-05-15

The sol-gel process provides an attractive low temperature alternative to the melt process for producing Ce-doped silica, but reports of the emission wavelength have not been consistent. In this paper, luminescence measurements using a variety of excitation methods, including cathodoluminescence not yet reported by other researchers, are compared and evaluated in the light of previously published data. Several papers report luminescence around 350 nm but emission near this wavelength was not found from our samples. This luminescence originates from Ce that has not yet been incorporated in the silica and is found in samples that have not undergone high temperature annealing. Our photoluminescence results from samples annealed in a reducing atmosphere suggest that emission from Ce incorporated in the silica lattice occurs near 455 nm, and some indication of the emission from Ce in amorphous clusters at 400 nm is also found. However, our results also confirm earlier indications that intrinsic defects in silica can create photoluminescence near both these wavelengths, which can make identification of the luminescence due to Ce difficult. Finally, it has been found that samples which have been annealed in air, and therefore display poor photoluminescence because most of the Ce occurs in the tetravalent form, are luminescent under electron beam excitation. It is suggested that during cathodoluminescence measurements Ce{sup 4+} ions capture electrons to form excited Ce{sup 3+} ions from which the luminescence originates.

Optically stimulated luminescence of ZnO obtained by thermal treatment of ZnS chemically synthesized

International Nuclear Information System (INIS)

Cruz V, C.; Burruel I, S.E.; Orante B, V.R.; Grijalva M, H.; Perez S, R.; Bernal, R.

2005-01-01

In this work, we report the optically stimulated luminescence (OSL) dosimetry of new nano phosphors of ZnO obtained by thermal annealing of chemically synthesized ZnS powder. The synthesized ZnS nano powder was compressed in order to form pellet shaped pellets, which were afterwards subjected to a thermal annealing at 700 C during 24 h under air atmosphere. X-ray diffraction (XRD) patterns and energy-disperse X-ray Spectrometry (EDS) analyses confirmed the transformation of ZnS to ZnO. Samples were exposed to several doses of beta radiation up to 600 Gy, and the optically stimulated luminescence with 470 nm wavelength light was recorded as a function of dose. The intensity of the OSL signal increases by increasing dose, for what it is concluded that these new phosphor materials are suitable to be used in optically stimulated luminescence dosimetry. (Author)

Uranyl fluoride luminescence in acidic aqueous solutions

International Nuclear Information System (INIS)

Beitz, J.V.; Williams, C.W.

1996-01-01

Luminescence emission spectra and decay rates are reported for uranyl species in acidic aqueous solutions containing HF or added NaF. The longest luminescence lifetime, 0.269 ± 0.006 ms, was observed from uranyl in 1 M HF + 1 M HClO 4 at 296 K and decreased with increasing temperature. Based on a luminescence dynamics model that assumes equilibrium among electronically excited uranyl fluoride species and free fluoride ion, this long lived uranyl luminescence in aqueous solution is attributed primarily to UO 2 F 2 . Studies on the effect of added LiNO 3 or Na 2 WO 4 ·2H 2 O showed relatively weak quenching of uranyl fluoride luminescence which suggests that high sensitivity determination of the UF 6 content of WF 6 gas should be feasible via uranyl luminescence analysis of hydrolyzed gas samples of impure WF 6

Investigations on the homogeneity of silica glass and on the order of X-amorphous silica by luminescence measurements

International Nuclear Information System (INIS)

Boden, G.

1982-08-01

Silica glasses melted from crystalline SiO 2 were exposed to ionizing radiation. At room temperature the spatial intensity distribution of the emitted luminescent radiation has been recorded by means of photographic or autoradiographic materials. Thereby schlieren and inhomogeneities are made visible and information is obtained on the melting process of the crystalline SiO 2 . Synthetic fused silica made from SiCl 4 shows no luminescent radiation. Depending on the penetration depth of the ionizing radiation the bulk or the surface of the sample can be studied. The decay curves of the integral luminescence intensity yield data on inhomogeneities in the silica glass leading to conclusions on order state and structure. The luminescence intensity and its half-life are a measure for the inhomogeneity of the silica glass and the existence of so-called 'preordered states'. This connection between luminescence intensity and the order state is found also with other X-amorphous SiO 2 modifications: silica gel, precipitated silicic acids, porous SiO 2 glasses, aerosil, thin SiO 2 layers, mechanically activated quartz: whereas no luminescence phenomena occur in disordered nearly ideally amorphous SiO 2 species, the luminescence increases with increasing order degree of the SiO 2 network and attains a high intensity in the case of the crystalline SiO 2 modifications quartz and cristobalite

Laser-induced incandescence of suspended particles as a source of excitation of dye luminescence

CERN Document Server

Zelensky, S

2003-01-01

The interaction of pulsed YAG-Nd sup 3 sup + laser radiation with submicron light-absorbing particles suspended in an aqueous solution of Rhodamine 6G is investigated experimentally. The experiments demonstrate that the laser-induced incandescence of suspended particles excites the luminescence of the dissolved dye molecules. The mechanism of the luminescence excitation consists in the reabsorption of the thermal radiation within the volume of the sample cell. On the ground of this mechanism of excitation, a method of measurement of the luminescence quantum yield is proposed and realized. The method requires the knowledge of the geometrical parameters of the cell and does not require the use of reference samples.

Material for a luminescent solar concentrator

Science.gov (United States)

Andrews, L.J.

1984-01-01

A material for use in a luminescent solar concentrator, formed by ceramitizing the luminescent ion Cr/sup 3 +/ with a transparent ceramic glass containing mullite. The resultant material has tiny Cr/sup 3 +/-bearing crystallites dispersed uniformly through an amorphous glass. The invention combines the high luminescent efficiency of Cr/sup 3 +/ in the crystalline phase with the practical and economical advantages of glass technology.

Wide-field time-resolved luminescence imaging and spectroscopy to decipher obliterated documents in forensic science

Science.gov (United States)

Suzuki, Mototsugu; Akiba, Norimitsu; Kurosawa, Kenji; Kuroki, Kenro; Akao, Yoshinori; Higashikawa, Yoshiyasu

2016-01-01

We applied a wide-field time-resolved luminescence (TRL) method with a pulsed laser and a gated intensified charge coupled device (ICCD) for deciphering obliterated documents for use in forensic science. The TRL method can nondestructively measure the dynamics of luminescence, including fluorescence and phosphorescence lifetimes, which prove to be useful parameters for image detection. First, we measured the TRL spectra of four brands of black porous-tip pen inks on paper to estimate their luminescence lifetimes. Next, we acquired the TRL images of 12 obliterated documents at various delay times and gate times of the ICCD. The obliterated contents were revealed in the TRL images because of the difference in the luminescence lifetimes of the inks. This method requires no pretreatment, is nondestructive, and has the advantage of wide-field imaging, which makes it is easy to control the gate timing. This demonstration proves that TRL imaging and spectroscopy are powerful tools for forensic document examination.

Virulence of luminescent and non-luminescent isogenic vibrios towards gnotobiotic Artemia franciscana larvae and specific pathogen-free Litopenaeus vannamei shrimp.

Science.gov (United States)

Phuoc, L H; Defoirdt, T; Sorgeloos, P; Bossier, P

2009-04-01

This study was conducted to test the virulence of luminescent (L) and non-luminescent (NL) isogenic strains of Vibrio campbellii LMG21363, Vibrio harveyi BB120 (wild type) and quorum-sensing mutant strains derived from the wild type such as Vibrio harveyi BB152, BB170, MM30 and BB886. The NL strains could be obtained by culturing rifampicin-resistant luminescent strains in the dark under static condition. The virulence of the L and NL strains was tested in gnotobiotic Artemia franciscana larvae challenged with 10(4) CFU ml(-1) of bacteria. All luminescent isogenic tested strains showed higher virulence compared to the NL strains. The virulence of L and NL V. campbellii and V. harveyi BB120 was also tested in specific pathogen-free juvenile shrimp upon intramuscular injection with 10(6) CFU of bacteria. In contrast with Artemia, there was no significant difference in mortality between the groups challenged with L and NL strains (P > 0.05). The non-luminescent strains were not able to revert back to the luminescent state and quorum sensing did not influence this phenotypic shift. Luminescent Vibrio strains can switch to a non-luminescent state by culturing them in static conditions. The NL strains become less virulent as verified in Artemia. The luminescent state of Vibrio cells in a culture needs to be verified in order to assure maintenance of virulence.

Growth and luminescence properties of Eu:SrI.sub.2./sub. single crystals prepared by modified micro-pulling-down method

Czech Academy of Sciences Publication Activity Database

Král, Robert; Jarý, Vítězslav; Pejchal, Jan; Kurosawa, S.; Nitsch, Karel; Yokota, Y.; Nikl, Martin; Yoshikawa, A.

2016-01-01

Roč. 63, č. 2 (2016), s. 453-458 ISSN 0018-9499 R&D Projects: GA MŠk(CZ) LH14266 Institutional support: RVO:68378271 Keywords : Eu 2+ and Eu 3+ doping * crystal growth * luminescence * micro-pulling-down method * strontium iodide Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.171, year: 2016

Luminescence of uranyl ion complexed with 2,6-pyridine dicarboxylic acid as ligand in acetonitrile medium. Observation of co-luminescence

Energy Technology Data Exchange (ETDEWEB)

Maji, Siuli; Kumar, Satendra; Sankaran, Kannan [Indira Ghandi Centre for Atomic Research, Tamil Nadu (India). Materials Chemistry Div.

2017-10-01

Luminescence from UO{sub 2}{sup 2+} (uranyl ion) complexed with 2,6-pyridine dicarboxylic acid (PDA) has been studied using acetonitrile (MeCN) as solvent between pH 1.0 and 6.0. The enhancement in luminescence intensity because of sensitization by PDA in the non-aqueous environment provided by the MeCN is found to be one order better than in aqueous medium. The luminescence is further enhanced by about four times following the addition of Y{sup 3+}; a process known as co-luminescence. This is the first study on co-luminescence of uranyl ion in its PDA complex. Lifetime studies indicate the presence of two species having different micro-environments. Formations of both intra and inter molecular complexes are believed to be responsible for enhancement due to co-luminescence.

Luminescence of uranyl ion complexed with 2,6-pyridine dicarboxylic acid as ligand in acetonitrile medium. Observation of co-luminescence

International Nuclear Information System (INIS)

Maji, Siuli; Kumar, Satendra; Sankaran, Kannan

2017-01-01

Luminescence from UO_2"2"+ (uranyl ion) complexed with 2,6-pyridine dicarboxylic acid (PDA) has been studied using acetonitrile (MeCN) as solvent between pH 1.0 and 6.0. The enhancement in luminescence intensity because of sensitization by PDA in the non-aqueous environment provided by the MeCN is found to be one order better than in aqueous medium. The luminescence is further enhanced by about four times following the addition of Y"3"+; a process known as co-luminescence. This is the first study on co-luminescence of uranyl ion in its PDA complex. Lifetime studies indicate the presence of two species having different micro-environments. Formations of both intra and inter molecular complexes are believed to be responsible for enhancement due to co-luminescence.

Receptor-Targeted Luminescent Silver Bionanoparticles

NARCIS (Netherlands)

Bunschoten, Anton; Chin, Patrick T.K.; Buckle, Tessa; Linden, van der Marte; Barendregt, Arjan; Verheijen, Marcel A.; Leeuwen, van Fijs W.B.

2016-01-01

Luminescent Ag nanoclusters (Ag-NC) provide the next generation in bionanoparticles, wherein the luminescence (650 nm) and large Stokes shift of these inorganic nanoclusters are favorable for biological imaging. By combining these characteristics with those of human serum albumin (HSA; a protein

Luminescent properties of europium different-ligand complexes with cyclic. beta. -diketones and diantipyrylalkanes

Energy Technology Data Exchange (ETDEWEB)

Ul' yanova, T M; Gerasimenko, G N; Tishchenko, M A; Vitkun, R A [AN Ukrainskoj SSR, Odessa. Fiziko-Khimicheskij Inst.

1983-03-01

Using luminescence method different-ligand complexing of europium ions with diantipyrylalkanes and cyclic ..beta..-diketones: 2-acetyl- and 2-benzoyl-1.3-indandions, has been studied. The optimum conditions of the formation of different-ligand complexes and the ratio of components in it are determined. Effect of alien lanthanides and diantipyrylmethane derivatives on the luminescence intensity of europium complexes is clarified. A correlation between the ratio of the luminescence intensity bands of europium complexes and the values of oscillator strengths of supersensitive transitions of neodymium and erbium absorption bands is established.

New polymers containing BF{sub 2}-benzoylacetonate groups. Synthesis, luminescence, excimer and exciplex formation

Energy Technology Data Exchange (ETDEWEB)

Fedorenko, Elena V., E-mail: gev@ich.dvo.ru [Institute of Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 159, Prosp. 100 letiya Vladivostoka, Vladivostok 690022 (Russian Federation); Mirochnik, Anatolii G.; Beloliptsev, Anton Yu. [Institute of Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 159, Prosp. 100 letiya Vladivostoka, Vladivostok 690022 (Russian Federation)

2017-05-15

In the present study, a new synthetic method for the functionalization of polystyrene (PS) and (styrene-methyl methacrylate) copolymer has been developed. Using the new method, polymers containing BF{sub 2}-benzoylacetonate groups have been obtained through double acylation by acetic anhydride with boron trifluoride. Luminescence of the produced polymers in solutions and films has been studied. Quantum yields of polymer solution luminescence are significantly higher than those of the low-molecular-weight analog – boron difluoride benzoylacetonate. For the polymer, in which styrene fragments are separated by methyl methacrylate groups, at low concentrations of the polymer in solution one observes the monomer luminescence of BF{sub 2}-benzoylacetonate groups, while at high concentrations – the excimer luminescence. In case of PS-based polymers, in which BF{sub 2}-benzoylacetonate groups and phenyl rings are not separated, in diluted solutions one observes the fluorescence of the intramolecular exciplexes, while at the concentration increase – the luminescence of intermolecular exciplexes. The ability of excimer formation is responsible for the increased photostability of the produced polymers. - Highlights: •Polymers containing BF{sub 2}-benzoylacetonate groups have been synthesized. •Luminescence of the produced polymers in solutions and films has been studied. •Formation of excimers and exciplexes in solution has been revealed. •Formation of excimers in films increases their photostability.

Near-Infrared Quantum Cutting Long Persistent Luminescence

OpenAIRE

Zou, Zehua; Feng, Lin; Cao, Cheng; Zhang, Jiachi; Wang, Yuhua

2016-01-01

By combining the unique features of the quantum cutting luminescence and long persistent luminescence, we design a new concept called ?near-infrared quantum cutting long persistent luminescence (NQPL)?, which makes it possible for us to obtain highly efficient (>100%) near-infrared long persistent luminescence in theory. Guided by the NQPL concept, we fabricate the first NQPL phosphor Ca2Ga2GeO7:Pr3+,Yb3+. It reveals that both the two-step energy transfer of model (I) and the one-step energy ...

Enhancing and quenching luminescence with gold nanoparticle films: the influence of substrate on the luminescent properties

International Nuclear Information System (INIS)

Guidelli, Eder José; Baffa, Oswaldo; Ramos, Ana Paula

2016-01-01

Gold nanoparticle (AuNP) films were sputtered over glass and aluminum substrates to enhance optically stimulated luminescence (OSL), a luminescent technique employed for radiation detection, from x-ray irradiated NaCl nanocrystals. The AuNP films deposited over glass led to enhanced-OSL emission, whereas the AuNP films deposited on aluminum substrates quenched the OSL emission. The enhanced-OSL intensity is proportional to the optical density of the film's plasmon resonance band at the stimulation wavelength. For the case of the AuNP/aluminum films, the luminescence quenching diminishes, and OSL intensity partially recovers upon increasing the distance between the AuNPs and the aluminum substrates, and between the luminescent nanocrystals and the AuNP films. These results suggest that plasmonic interactions between the emitter nanocrystals, the localized surface plasmons (LSP) of the AuNPs, and the substrate are responsible for the OSL enhancement and quenching. In this sense, the substrate dictates whether LSP relaxation occurs by radiative or non-radiative transisitions, leading to enhanced or quenched OSL, respectively. Therefore, besides showing that AuNP films can enhance and/or tune the sensitivity of luminescent radiation detectors, and demonstrating OSL as a new technique to investigate mechanisms of plasmon-enhanced luminescence, these results bring insights on how substrates strongly modify the optical properties of AuNP films. (paper)

A deepwater fish with 'lightsabers'--dorsal spine-associated luminescence in a counterilluminating lanternshark.

Science.gov (United States)

Claes, Julien M; Dean, Mason N; Nilsson, Dan-Eric; Hart, Nathan S; Mallefet, Jérôme

2013-01-01

We report the discovery of light organs (photophores) adjacent to the dorsal defensive spines of a small deep-sea lanternshark (Etmopterus spinax). Using a visual modeling based on in vivo luminescence recordings we show that this unusual light display would be detectable by the shark's potential predators from several meters away. We also demonstrate that the luminescence from the spine-associated photophores (SAPs) can be seen through the mineralized spines, which are partially translucent. These results suggest that the SAPs function, either by mimicking the spines' shape or by shining through them, as a unique visual deterrent for predators. This conspicuous dorsal warning display is a surprising complement to the ventral luminous camouflage (counterillumination) of the shark.

Luminescence (IRSL) dating of Yeni Rabat church in Artvin, Turkey

International Nuclear Information System (INIS)

Şahiner, Eren; Meriç, Niyazi; Uygun, Selda

2013-01-01

Luminescence dating is a chronological method that has been used extensively in terrestrial materials. In this study, we present Infrared Stimulated Luminescence (IRSL) dating results obtained for sediment and pottery samples taken from Yeni Rabat Church, Ardanuç, Artvin, Turkey. For this purpose, equivalent dose (ED) and annual dose rate (AD) of samples were measured. For annual dose rate, concentrations of radioactive isotopes (U, Th, K) were determined by using a high-purity germanium detector. For the equivalent dose, polymineral fine grain SAR (Single Aliquot Regenerative Dose) and MAAD (Multiple Aliquot Additive Dose) procedures were used. The optimal preheat temperature was determined for sediment and pottery samples. Ages were calculated by Aitken's luminescence age calculation method, which found 710±190 years for the pottery sample and 1450±370 years, 1390±420 years, 1430±310 years, 2210±520 years and 1640±390 years for different sediment samples, respectively. These estimated age ranges support the theory that Yeni Rabat Church could have been constructed in medieval times. - Highlights: ► The luminescence (IRSL) ages of the samples, taken from in Yeni Rabat church in Artvin-Turkey were found. ► Equivalent doses and annual doses were determined. ► Polymineral fine grain SAR (Single Aliquot Regenerative Dose) and MAAD (Multiple Aliquot Additive Dose) procedures were used

Novel Luminescent Multilayer Films Containing π-Conjugated Anionic Polymer with Electronic Microenvironment

Directory of Open Access Journals (Sweden)

Tianlei Wang

2016-09-01

Full Text Available Layered double hydroxides (LDHs, luminescent π-conjugated anionic polymer and montmorillonite (MMT were orderly assembled into luminescent multilayer films via layer-by-layer self-assembly method. The electronic microenvironment (EME, the structure of which is like a traditional capacitor, can be constructed by exfoliated LDHs or MMT nanosheets. In addition, the rigid inorganic laminated configuration can offer stable surroundings between the interlayers. As a result, we conclude that EME can extend the luminescent lifespans of multilayer films substantially, due to affecting relaxation times of π-conjugated anionic polymer. Consequently, because of the remarkable impact on better photoemission behaviors of luminescent π-conjugated anionic polymer, EME assembled by LDHs or MMT nanosheets have had high hopes attached to them. They are expected to have the potential for designing, constructing, and investigating novel light-emitting thin films.

Experimental and modelling study of pulsed optically stimulated luminescence in quartz, marble and beta irradiated salt

International Nuclear Information System (INIS)

Pagonis, V; Mian, S M; Barnold, C; Chithambo, M L; Christensen, E

2009-01-01

Optical stimulation luminescence (OSL) signals can be obtained using continuous-wave optical stimulation (CW-OSL), the linear modulation optical stimulation method (LM-OSL) and the time-resolved optical stimulation (TR-OSL) method. During TR-OSL measurements, the stimulation and emission of luminescence are experimentally separated in time by using short light pulses. This paper presents new TR-OSL data for annealed high purity synthetic quartz, for marble and for commercially available iodized salt. A new type of behaviour for TR-OSL signals for quartz and iodized salt is presented, in which the OSL signal exhibits a nonmonotonic behaviour during optical stimulation; this type of behaviour has not been reported previously in the literature for quartz. Furthermore, a luminescence component with very long luminescence lifetime is reported for some quartz aliquots, which may be due to the presence of a delayed-OSL (DOSL) mechanism in quartz. A new kinetic model for TR-OSL in quartz is presented, which is based on a main electron trap and on several luminescence centres. The model is used to quantitatively fit several sets of experimental data of pulsed optically stimulated luminescence from quartz.

Radiation-induced damage analysed by luminescence methods in retrospective dosimetry and emergency response.

Science.gov (United States)

Woda, Clemens; Bassinet, Céline; Trompier, François; Bortolin, Emanuela; Della Monaca, Sara; Fattibene, Paola

2009-01-01

The increasing risk of a mass casualty scenario following a large scale radiological accident or attack necessitates the development of appropriate dosimetric tools for emergency response. Luminescence dosimetry has been reliably applied for dose reconstruction in contaminated settlements for several decades and recent research into new materials carried close to the human body opens the possibility of estimating individual doses for accident and emergency dosimetry using the same technique. This paper reviews the luminescence research into materials useful for accident dosimetry and applications in retrospective dosimetry. The properties of the materials are critically discussed with regard to the requirements for population triage. It is concluded that electronic components found within portable electronic devices, such as e.g. mobile phones, are at present the most promising material to function as a fortuitous dosimeter in an emergency response.

Luminescence dating of Netherland's sediments

NARCIS (Netherlands)

Wallinga, J.; Davids, F.; Dijkmans, J.W.A.

2007-01-01

Over the last decades luminescence dating techniques have been developed that allow earth scientists to determine the time of deposition of sediments. In this contribution we revity: 1) the development of the methodology, 2) tests of the reliability of luminescence dating on Netherlands' sediments;

Luminescence enhancement of ZnO-poly(methylmethacrylate) nanocomposite films by incorporation of crystalline BaTiO{sub 3} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Kanamori, Tsuyoshi; Han, Yu; Nagao, Daisuke, E-mail: dnagao@tohoku.ac.jp; Kamezawa, Nao; Ishii, Haruyuki; Konno, Mikio

2016-09-15

Highlights: • Dielectric barium titanate (BT) nanoparticles incorporated into luminescence films. • Luminescence intensities increased by the BT nanoparticle incorporation. • Incorporation of highly dielectric nanoparticles effective for luminescence enhancement. - Abstract: Incorporation of highly dielectric nanoparticles into luminescent ZnO-polymethylmethacrylate (PMMA) nanocomposite films was undertaken to examine the effect of nanoparticle incorporation on luminescence intensity of the nanocomposite films. ZnO nanoparticles were prepared as inorganic phosphors by a precipitation method. The ZnO nanoparticles were then surface-modified with 3-methacryloxypropyltrimethoxysilane (MPTMS) to be used for fabrication of the ZnO-PMMA nanocomposite film. Barium titanate (BT) nanoparticles were synthesized with a sol-gel method as the highly dielectric nanoparticles, which were also surface-modified with the MPTMS for the incorporation into the nanocomposite films. Luminescence intensity of the nanocomposite films was successfully increased by the nanoparticle incorporation up to a BT content around 15 vol%. The luminescence intensity higher than that measured for the nanocomposite films incorporating SiO{sub 2} nanoparticles indicated that the incorporation of highly dielectric nanoparticles was an effective approach to enhance the luminescence of ZnO nanoparticles in the polymer thin films.

Dating Last Interglacial Coastal Systems Using New Feldspar Luminescence Technologies

Science.gov (United States)

Lamothe, M.

2017-12-01

The recent explosion in new luminescence dating technologies offers new opportunities to explore Quaternary marine coastal facies and landforms. However, tectonic and climatic processes controlling the development of Pleistocene coastal lithosomes are commonly obscured by their poorly constrained geological age. Luminescence dating of feldspar probes one order of magnitude deeper into geological time than radiocarbon and more than 5 times the current age range of quartz optically-stimulated luminescence, routinely used in luminescence dating. However, feldspar luminescence stimulated by infrared photons (eg IRSL) is hampered by anomalous fading. Successful correction methods developed by us over the last 15 years did produce sound chronologies but the fading-corrected ages carried large uncertainties. New approaches initiated by other laboratories, mainly in Europe, have isolated high temperature post-IRSL luminescence as this signal seems to be only slightly affected by fading. However, the gain in stability seems to be lessened due to bleachibility issues, generating age overestimations. We developed a novel protocol known as post-isothermal IRSL dating (Pit-IR) that focuses on a dual system of luminescence signals, probing low (50C) and medium (225C) temperature IRSL signals following isothermal treatments of various intensities. These protocols have been tested on Last interglacial coastal sediments in strikingly different GIA contexts along the Atlantic coastal areas of SE USA as well as from Morocco, Brazil and LIG sites in the Mediterranean basin. A systematic analysis of these results would suggest that a) falling-stages sequences are more commonly preserved as the OSL/IRSL ages are preferentially dating from the end of the MIS5e high stand and b) MIS5a marine sediments may be detectable away from areas generally thought to be affected by peripheral bulge collapse.

Mesoporous material grafted with luminescent molecules for the design of selective metal ion chemosensor

International Nuclear Information System (INIS)

Zhang Huidong; Zhang Ping; Ye Kaiqi; Sun Yinghui; Jiang Shimei; Wang Yue; Pang Wenqin

2006-01-01

Luminescent Schiff-base groups have been successfully grafted on the surface of mesoporous material MCM-48. The grafted Schiff-base groups were employed to prepare luminescent Schiff-base-Zn complex that was covalently bound to the MCM-48 surface. These luminescent mesoporous materials were characterized with X-ray, UV-VIS and emission spectroscopic methods. Experimental results demonstrated that MCM-48 modified with functional groups exhibited novel luminescent property. The chemosensing property of modified MCM-48 sample was investigated. It was demonstrated that the fluorescence of MCM-48 solid with Schiff-base groups could be completely quenched by Cu 2+ cation and this mesoporous material was suitable for sensing Cu 2+ cation in aqueous media

Luminescence thermometry with Eu{sup 3+} doped GdAlO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Lojpur, Vesna, E-mail: vesna.lojpur@yahoo.com; Ćulubrk, Sanja; Medić, Mina; Dramicanin, Miroslav

2016-02-15

Eu{sup 3+} doped GdAlO{sub 3} powder synthesized by solid state reaction was investigated for application in luminescence thermometry. Phase composition of material was confirmed by X-ray powder diffraction analysis. The photoluminescence emission spectra were collected under excitation of 399 nm, while elevating the temperature of the sample from the room temperature to 793 K. Emissions from {sup 5}D{sub 1}→{sup 7}F{sub 1} and {sup 5}D{sub 0}→{sup 7}F{sub 2} characteristic transitions of Eu{sup 3+} ions are selected for the temperature-dependence study using the fluorescence intensity ratio method. Emission decay curves measured at the strongest emission peak centered at 614 nm were recorded in a same temperature range. Data analysis showed that thermometry by fluorescence intensity ratio method can be used over the temperature region 293–793 K with the maximal relative sensitivity of 2.96% K{sup −1} (at 293 K). Temporal dependence of emission (lifetime) provides temperature sensing from 620 to 793 K with the maximal relative sensitivity of 2.28% K{sup −1}. - Highlights: • GdAlO{sub 3}: 4 at% of Eu{sup 3+} can be used for luminescence thermometry in the 293–793 K range. • Combined FIR and lifetime thermometry provide >0.5% K{sup −1} relative sensitivity. • Temperature dependence of lifetime is well described energy gap law model.

Luminescence (IRSL) dating of Yeni Rabat church in Artvin, Turkey

Science.gov (United States)

Şahiner, Eren; Meriç, Niyazi; Uygun, Selda

2013-05-01

Luminescence dating is a chronological method that has been used extensively in terrestrial materials. In this study, we present Infrared Stimulated Luminescence (IRSL) dating results obtained for sediment and pottery samples taken from Yeni Rabat Church, Ardanuç, Artvin, Turkey. For this purpose, equivalent dose (ED) and annual dose rate (AD) of samples were measured. For annual dose rate, concentrations of radioactive isotopes (U, Th, K) were determined by using a high-purity germanium detector. For the equivalent dose, polymineral fine grain SAR (Single Aliquot Regenerative Dose) and MAAD (Multiple Aliquot Additive Dose) procedures were used. The optimal preheat temperature was determined for sediment and pottery samples. Ages were calculated by Aitken's luminescence age calculation method, which found 710±190 years for the pottery sample and 1450±370 years, 1390±420 years, 1430±310 years, 2210±520 years and 1640±390 years for different sediment samples, respectively. These estimated age ranges support the theory that Yeni Rabat Church could have been constructed in medieval times.

Recent developments in luminescent solar concentrators

Science.gov (United States)

van Sark, W. G. J. H. M.

2014-10-01

High efficiency photovoltaic devices combine full solar spectrum absorption and effective generation and collection of charge carriers, while commercial success depends on cost effectiveness in manufacturing. Spectrum modification using down shifting has been demonstrated in luminescent solar concentrators (LSCs) since the 1970s, as a cheap alternative for standard c-Si technology. LSCs consist of a highly transparent plastic plate, in which luminescent species are dispersed, which absorb incident light and emit light at a red-shifted wavelength, with high quantum efficiency. Material issues have hampered efficiency improvements, in particular re-absorption of light emitted by luminescent species and stability of these species. In this contribution, approaches are reviewed on minimizing re-absorption, which should allow surpassing the 10% luminescent solar concentrator efficiency barrier.

Mathematical model quantifies multiple daylight exposure and burial events for rock surfaces using luminescence dating

International Nuclear Information System (INIS)

Freiesleben, Trine; Sohbati, Reza; Murray, Andrew; Jain, Mayank; Al Khasawneh, Sahar; Hvidt, Søren; Jakobsen, Bo

2015-01-01

Interest in the optically stimulated luminescence (OSL) dating of rock surfaces has increased significantly over the last few years, as the potential of the method has been explored. It has been realized that luminescence-depth profiles show qualitative evidence for multiple daylight exposure and burial events. To quantify both burial and exposure events a new mathematical model is developed by expanding the existing models of evolution of luminescence–depth profiles, to include repeated sequential events of burial and exposure to daylight. This new model is applied to an infrared stimulated luminescence-depth profile from a feldspar-rich granite cobble from an archaeological site near Aarhus, Denmark. This profile shows qualitative evidence for multiple daylight exposure and burial events; these are quantified using the model developed here. By determining the burial ages from the surface layer of the cobble and by fitting the new model to the luminescence profile, it is concluded that the cobble was well bleached before burial. This indicates that the OSL burial age is likely to be reliable. In addition, a recent known exposure event provides an approximate calibration for older daylight exposure events. This study confirms the suggestion that rock surfaces contain a record of exposure and burial history, and that these events can be quantified. The burial age of rock surfaces can thus be dated with confidence, based on a knowledge of their pre-burial light exposure; it may also be possible to determine the length of a fossil exposure, using a known natural light exposure as calibration. - Highlights: • Evidence for multiple exposure and burial events in the history of a single cobble. • OSL rock surface dating model improved to include multiple burial/exposure cycles. • Application of the new model quantifies burial and exposure events.

Review of present trends in luminescence research

International Nuclear Information System (INIS)

Williams, F.; Delaware Univ., Newark

1981-01-01

The difficulties of a comprehensive review of the broad and diverse branches of molecular and solid-state luminescence research are noted. This review is thus limited to selective topics. Some general concepts and trends are then introduced, including: luminescence excitation as a collective excitation of a many-body problem, encompassing in some cases the source and probe in its formulation; continuing trends towards extremal conditions of experiments and towards inhomogeneous and structured materials, from man-made superlattices to biological materials; and increased attention to applications of luminescence research to lamps, displays, solar devices and biological research. Representative recent and new specific research areas include: site selection spectroscopy and 'hole burning'; picosecond delayed coherent anti-Stokes Raman scattering; computer simulation of dynamical processes in luminescence; electron-hole expansion from the Fermi pressure of e-h plasmas; and hot electron phenomena and hot luminescence. Finally some pending problems in luminescence research, such as reconciling the configuration coordinate model and the electronic band theory and clarifying multi-phonon non-radiative processes, are discussed. (orig.)

Luminescent materials: probing the excited state of emission centers by spectroscopic methods

Czech Academy of Sciences Publication Activity Database

Mihóková, Eva; Nikl, Martin

2015-01-01

Roč. 26, č. 1 (2015), s. 1-17 ISSN 0957-0233 R&D Projects: GA ČR GA13-09876S Grant - others:AVČR(CZ) M100101212 Institutional support: RVO:68378271 Keywords : luminescence * rare- earth ions * ionization * tunneling * scintillators Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.492, year: 2015

LUMINESCENCE DETERMINATION OF ETODOLAC

Directory of Open Access Journals (Sweden)

A. V. Yegorova

2015-02-01

Full Text Available A highly sensitive, simple and rapid method for determination of non-steroidal anti- inflammatory drug – etodolac (Et in washings from surfaces of pharmaceutical equipment have been proposed. The intensity of native luminescence of water-n-propanol solutions of etodolac (λex= 274 nm; λlum= 350 nm was used as the analytical signal. The calibration graph is linear in the concentration range 0.014-2.3 μg/ml, the limit of detection is 0.5 ng/ml.

Time-resolved luminescent spectroscopy of YAG:Ce single crystal and single crystalline films

International Nuclear Information System (INIS)

Zorenko, Yu.; Gorbenko, V.; Savchyn, V.; Vozniak, T.; Puzikov, V.; Danko, A.; Nizhankovski, S.

2010-01-01

The peculiarities of the luminescence and energy transfer from YAG host to the emission centers formed by the Y Al antisite defects and Ce 3+ ions have been studied in YAG:Ce single crystals, grown from the melt by modified Bridgman method in Ar and CO 2 + H 2 atmospheres, and YAG:Ce single crystalline film, grown by liquid phase epitaxy method, using the comparative time-resolved luminescent spectroscopy under excitation by synchrotron radiation in the range of fundamental adsorption of this garnet.

Towards Luminescence Dating Of Mosaic Glass

Science.gov (United States)

Galli, A.; Martini, M.; Sibila, E.; Villa, I.

The possibility of dating archaeological glass by means of luminescent techniques has been investigated in recent years, despite the difficulties of this application, mainly linked to the amorphous structure of the material. We focused in particular on mosaic glass, after the encouraging results obtained on byzantine and medieval samples. Further studies were devoted to the comprehension of the luminescent mechanisms in silica glasses, and to the investigation of the relationships between luminescence, colouring or opacifier ions and crystalline phase of the vitreous matrix. The results of a study on the dosimetric characteristics of thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) of a few medieval blue-green mosaic glasses from the San Lorenzo church (Milan) are presented, and the experimental protocols established to identify their suitability for dating are discussed.

Quantitative cone beam X-ray luminescence tomography/X-ray computed tomography imaging

International Nuclear Information System (INIS)

Chen, Dongmei; Zhu, Shouping; Chen, Xueli; Chao, Tiantian; Cao, Xu; Zhao, Fengjun; Huang, Liyu; Liang, Jimin

2014-01-01

X-ray luminescence tomography (XLT) is an imaging technology based on X-ray-excitable materials. The main purpose of this paper is to obtain quantitative luminescence concentration using the structural information of the X-ray computed tomography (XCT) in the hybrid cone beam XLT/XCT system. A multi-wavelength luminescence cone beam XLT method with the structural a priori information is presented to relieve the severe ill-posedness problem in the cone beam XLT. The nanophosphors and phantom experiments were undertaken to access the linear relationship of the system response. Then, an in vivo mouse experiment was conducted. The in vivo experimental results show that the recovered concentration error as low as 6.67% with the location error of 0.85 mm can be achieved. The results demonstrate that the proposed method can accurately recover the nanophosphor inclusion and realize the quantitative imaging

Luminescent amine sensor based on europium(III) chelate.

Science.gov (United States)

Petrochenkova, Nataliya V; Mirochnik, Anatolii G; Emelina, Tatyana B; Sergeev, Alexander A; Leonov, Andrei A; Voznesenskii, Sergey S

2018-07-05

The effect of methylamine vapor on luminescence of Eu(III) tris-benzoylacetonate (I) immobilized in thin-layer chromatography plates has been investigated. It has been revealed that interaction of I with analyte vapor results in increase of the intensity of Eu(III) luminescence. The mechanism of the effect of methylamine vapors on intensification of the Eu(III) luminescence has been suggested using the data of IR spectroscopy and quantum chemistry calculations. The mechanism of luminescence sensitization consists in bonding of an analyte molecule with a water molecule into the coordination sphere of Eu(III). As a result, the bond of a water molecule with the luminescence centre weakens, rigid structural fragment including europium ion, water and methylamine molecules forms. The presence of such fragment must naturally promote decrease of influence of OH-vibrations on luminescence of the complex I. Copyright © 2018 Elsevier B.V. All rights reserved.

Silica nanoparticles with a substrate switchable luminescence

International Nuclear Information System (INIS)

Bochkova, O D; Mustafina, A R; Fedorenko, S V; Konovalov, A I

2011-01-01

Silica nanoparticles with visible (Tb and Ru doped), near IR (Yb doped) and dual visible-near IR luminescence (Ru-Yb doped) were obtained by reverse w/o microemulsion procedure. Plenty of luminescent complexes (from 4900 to 10000) encapsulated into each nanoparticle ensures the intensive luminescence of nanoparticles and their applicability as biomarkers. The silica surface decoration by definite anchor groups is the required step for the gaining to these nanoparticles marking and sensing functions. Thus covalent and non-covalent surface modification of these nanoparticles was developed to provide the binding with biotargets and sensing of anions. The dicationic surfactant coating of negatively charged Tb(III)-TCAS doped silica nanoparticles was chosen as the basis for the anion responsible system. The reversible insertion of the quenching anions (namely phenol red) into the surfactant based layer at the surface of luminescent nanoparticles switches off the Tb-centered luminescence. In turn the reversible reestablishment of the luminescence results from the competitive insertion of the non-quenching anions into the surfactant layer at the silica/water interface. The hydrophobic anions exemplified by dodecylsulfates versus hydrophilic ones (hydrophosphates) are preferable in the competition with phenol red anions.

Microwave assisted synthesis of luminescent carbonaceous nanoparticles from silk fibroin for bioimaging.

Science.gov (United States)

Gao, Hongzhi; Teng, Choon Peng; Huang, Donghong; Xu, Wanqing; Zheng, Chaohui; Chen, Yisong; Liu, Minghuan; Yang, Da-Peng; Lin, Ming; Li, Zibiao; Ye, Enyi

2017-11-01

Bombyx mori silk as a natural protein based biopolymer with high nitrogen content, is abundant and sustainable because of its mass product all over the world per year. In this study, we developed a facile and fast microwave-assisted synthesis of luminescent carbonaceous nanoparticles using Bombyx mori silk fibroin and silk solution as the precursors. As a result, the obtained carbonaceous nanoparticles exhibit a photoluminescence quantum yield of ~20%, high stability, low cytotoxicity, high biocompatibility. Most importantly, we successfully demonstrated bioimaging using these luminescent carbonaceous nanoparticles with excitation dependent luminescence. In addition, the microwave-assisted hydrothermal method can be extended to convert other biomass into functional nanomaterials. Copyright © 2017 Elsevier B.V. All rights reserved.

Luminescent properties of terbium complexes with catecholamines and their application in analysis

International Nuclear Information System (INIS)

Kravchenko, T.B.; Bel'tyukova, S.V.; Kononenko, L.I.; Poluehktov, N.S.

1982-01-01

Tb complexing with a representative of catecholamines - adrenaline - is studied using the luminescence method. It is found, that the complexing takes place in alkaline medium (pH 12.0). To prevent from compound oxidation with air oxygen and to create the necessary pH in solution sodium borohydride is used. The highest luminescence intensity is achieved when the reaction occurs in aqueous-isopropanol solutions. It is established that in the complexes formed the ratio of components is the following: Tb:adrenaline=1:3. Luminescent properties of Tb complex with adrenaline are used to determine the latter. The least detectable amount of adrenaline constitutes 0.02 μg, the determination error does not exceed 5.5% [ru

Uranyl(VI) luminescence spectroscopy at elevated temperatures

Energy Technology Data Exchange (ETDEWEB)

Steudtner, Robin; Franzen, Carola; Brendler, Vinzenz [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Div. Surface Processes; Haubitz, Toni [Brandenburg Univ. of Technology, Cottbus-Senftenberg (Germany)

2016-07-01

We studied the influence of temperature and ionic strength on the luminescence characteristics (band position, decay time and intensity) of the free uranyl ion (UO{sub 2}{sup 2+}) in acidic aqueous solution. Under the chosen conditions an increasing temperature reduced both intensity and luminescence decay time of the UO{sub 2}{sup 2+} luminescence, but the individual U(VI) emission bands did not change.

Sub-ppb level detection of uranium using ligand sensitized luminescence

International Nuclear Information System (INIS)

Kumar, Satendra; Maji, S.; Joseph, M.; Sankaran, K.

2015-01-01

Uranyl ion (UO 2 2+ ) is known to exhibit weak luminescence in aqueous medium due to poor molar absorptivity and low quantum yield. In order to enhance the luminescence of uranyl ion in aqueous medium, luminescence enhancing reagents such as H 3 PO 4 , H 2 SO 4 , HClO 4 have been widely used. Like lanthanides, uranyl luminescence can also be sensitized by using some organic ligands. Pyridine 2,6-dicarboxylic acid (PDA) has shown enhancement of luminescence of uranyl in aqueous medium. Enhancement in intensity is due to sensitization of uranyl luminescence by PDA. In order to see the effect of non-aqueous medium, in this work, luminescence of uranyl-PDA complex has been studied in acetonitrile medium. More than one order luminescence enhancement has been observed compared to UO 2 2+ - PDA complex in aqueous medium. The lifetime of uranyl luminescence of the complex in acetonitrile medium is 90 μs which is very high compared to 10 μs in aqueous medium, suggesting that the luminescence enhancement is a result of reduction in non-radiative decay channels in acetonitrile medium. The large enhancement of uranyl luminescence of uranyl-PDA complex in acetonitrile medium can be used for ultra-trace level detection of uranium. Linearity in the luminescence intensity has been observed over the uranium concentration range of 5 to 80 ppb and the detection limit calculated using the criterion of 3 σ is ~ 0.2 ppb. (author)

Annealing temperatures influence luminescence of YBO{sub 3}: Ce{sup 3+}, Yb{sup 3+} prepared by solvothermal method

Energy Technology Data Exchange (ETDEWEB)

Wang, Yue [Department of Physics, Northwest University, No. 229 Taibai North Road, Xi' an, Shaanxi, 710069 (China); Hu, Xiaoyun, E-mail: hxy3275@nwu.edu.cn [Department of Physics, Northwest University, No. 229 Taibai North Road, Xi' an, Shaanxi, 710069 (China); Zhan, Suchang; Sun, Xiao; Wang, Zhizhong; Miao, Tian; Miao, Hui [Department of Physics, Northwest University, No. 229 Taibai North Road, Xi' an, Shaanxi, 710069 (China); Fan, Jun [School of Chemical Engineering, Northwest University, No. 229 Taibai North Road, Xi' an, Shaanxi, 710069 (China)

2014-08-01

Near-infrared (NIR) quantum cutting (QC) YBO{sub 3}: Ce{sup 3+}, Yb{sup 3+} phosphors have been synthesized by solvothermal method with further heat treatment. The emission spectrum shows the Vis and NIR emission intensity of samples are both increasingly strong as annealing temperature rises when the annealing temperature is above 600 °C. Meanwhile the Vis emission of unannealed sample is observed. SEM images show that the sample annealed at different temperatures (200–900 °C) is mainly composed of nanosheets like potato chips, which is melt down granules after annealing treatment above 1000 °C.The crystal texture of all samples whether annealed or not is hexagonal through the analysis of XRD. The Raman and infrared spectrums indicate that the boron ions exist of BO{sub 4} units when the annealing temperature is above 600 °C. The infrared profile of unannealed sample shows that there are N–H units in the samples without annealing treatment. - Highlights: • The nanosheets like potato chips are synthesized by solvothermal method. • Annealing temperature is a great effect for luminescence of sample. • The boron ions exist of BO{sub 4} when the annealing temperature is above 600 °C, whose quantity determines the luminescent intensity. • According to the infrared profile of unannealed sample, there are N–H units, which are beneficial to the Vis emission.

Dosimetry based on thermally and optically stimulated luminescence

International Nuclear Information System (INIS)

Agersnap Larsen, Niels

1999-01-01

Thermally Stimulated Luminescence (TL) and Optically Stimulated Luminescence (OSL) properties of quartz and α-Al 2 O 3 have been investigated. Anneling-induced OSL and TL sensitivity changes in quartz has been investigated by experiments and modelling. This study does not support a pre-dose effect to account for the observed annealing-induced sensitivity change. The experimental data indicates a more simple mechanism that involves alteration of the concentration of the defect centers. Results from modelling of removal or creation of defect centers comparing well with experimentally obtained data. Thermal quenching of luminescence for the main emission center, the F-center, in α-Al 2 O 3 :C has been investigated by analysing TL curves obtained at different heating rates. The thermal quenching dependence of luminescence is found to follow the classical Mott-Seitz expression. Basic investigations of OSL properties of αAl 2 O 3 :C, including: the thermal depth of the OSL traps, the temperature dependence of OSL, and the OSL stimulation spectra. Simultaneous measurements of TL and thermally stimulated conductivity (TSC) are presented for γ-irradiated αAl 2 O 3 :C. Activation energy analysis of the data reveals a superposition of several first-order TL and TSC peaks caused by release of charge carriers from a distribution of trapping states. Furthermore a description of an experimental method developed to determine the sign of the thermally released charge carriers has been presented. (au)

Cultivating Fluorescent Flowers with Highly Luminescent Carbon Dots Fabricated by a Double Passivation Method.

Science.gov (United States)

Han, Shuai; Chang, Tao; Zhao, Haiping; Du, Huanhuan; Liu, Shan; Wu, Baoshuang; Qin, Shenjun

2017-07-07

In this work, we present the fabrication of highly luminescent carbon dots (CDs) by a double passivation method with the assistance of Ca(OH)₂. In the reaction process, Ca 2+ protects the active functional groups from overconsumption during dehydration and carbonization, and the electron-withdrawing groups on the CD surface are converted to electron-donating groups by the hydroxyl ions. As a result, the fluorescence quantum yield of the CDs was found to increase with increasing Ca(OH)₂ content in the reaction process. A blue-shift optical spectrum of the CDs was also found with increasing Ca(OH)₂ content, which could be attributed to the increasing of the energy gaps for the CDs. The highly photoluminescent CDs obtained (quantum yield: 86%) were used to cultivate fluorescent carnations by a water culture method, while the results of fluorescence microscopy analysis indicated that the CDs had entered the plant tissue structure.

Luminescence quantum efficiency determination in LiYF4:Nd3+ using photoacoustic spectroscopy

International Nuclear Information System (INIS)

Franca, E.J.

1989-01-01

Optical properties of LiYF 4 :Nd 3+ were studied using absorption, emission, excitation and photo acoustic spectroscopies. The Nd 3+ transitions were identified and the Stark sublevels were determined for the 4 I 9/2 , 4 I 11/2 and 4 F 3/2 levels. It is also presented and analysed three methods for the luminescence quantum efficiency determination, based on parameters from the spectra mentioned above. These methods were applied to four groups centered on 517, 577, 743 and 792nm. The first method provided values too high due to its assumption that the material has only one luminescent channel. The values obtained from the second one are still somewhat high but closer to the expected ones. The superestimation can be atributed to the imprecision in the existing branching ratios values, needed in this method. The third one, developed from the other two, provided values closer to the expected ones, but also affected by experimental conditions limitations, mainly related to the spectral resolution of the photoacustic spectra. The obtained results show that this method, once improved and associated to better experimental conditions, will lead to more accurate luminescence quantum efficiency values. (author) [pt

Apparatus for reducing solvent luminescence background emissions

Energy Technology Data Exchange (ETDEWEB)

Affleck, Rhett L. (Los Alamos, NM); Ambrose, W. Patrick (Los Alamos, NM); Demas, James N. (Charlottesville, VA); Goodwin, Peter M. (Jemez Springs, NM); Johnson, Mitchell E. (Pittsburgh, PA); Keller, Richard A. (Los Alamos, NM); Petty, Jeffrey T. (Los Alamos, NM); Schecker, Jay A. (Sante Fe, NM); Wu, Ming (Los Alamos, NM)

1998-01-01

The detectability of luminescent molecules in solution is enhanced by reducing the background luminescence due to impurity species also present in the solution. A light source that illuminates the solution acts to photolyze the impurities so that the impurities do not luminesce in the fluorescence band of the molecule of interest. Molecules of interest may be carried through the photolysis region in the solution or may be introduced into the solution after the photolysis region.

MO-FG-CAMPUS-JeP1-03: Luminescence Imaging of Water During Proton Beam Irradiation for Range Estimation

International Nuclear Information System (INIS)

Yamamoto, S; Komori, M; Toshito, T; Watabe, H

2016-01-01

Purpose: Since proton therapy has the ability to selectively deliver a dose to a target tumor, the dose distribution should be accurately measured. A precise and efficient method to evaluate the dose distribution is desired. We found that luminescence was emitted from water during proton irradiation and thought this phenomenon could be used for estimating the dose distribution. Methods: For this purpose, we placed water phantoms set on a table with a spot-scanning proton-therapy system, and luminescence images of these phantoms were measured with a high-sensitivity cooled charge coupled device (CCD) camera during proton-beam irradiation. We also conducted the imaging of phantoms of pure-water, fluorescein solution and acrylic block. We made three dimensional images from the projection data. Results: The luminescence images of water phantoms during the proton-beam irradiations showed clear Bragg peaks, and the measured proton ranges from the images were almost the same as those obtained with an ionization chamber. The image of the pure-water phantom also showed almost the same distribution as the tap-water phantom, indicating that the luminescence image was not related to impurities in the water. The luminescence image of fluorescein solution had ∼3 times higher intensity than water, with the same proton range as that of water. The luminescence image of the acrylic phantom had 14.5% shorter proton range than that of water; the proton range in the acrylic phantom was relatively matched with the calculated value. The luminescence images of the tap-water phantom during proton irradiation could be obtained in less than 2 sec. Three dimensional images were successfully obtained which have more quantitative information. Conclusion: Luminescence imaging during proton-beam irradiation has the potential to be a new method for range estimations in proton therapy.

MO-FG-CAMPUS-JeP1-03: Luminescence Imaging of Water During Proton Beam Irradiation for Range Estimation

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, S; Komori, M [Nagoya University, Nagoya, Aichi (Japan); Toshito, T [Nagoya Proton Therapy Center, Nagoya, Aichi (Japan); Watabe, H [Tohoku University, Sendai, Miyagi (Japan)

2016-06-15

Purpose: Since proton therapy has the ability to selectively deliver a dose to a target tumor, the dose distribution should be accurately measured. A precise and efficient method to evaluate the dose distribution is desired. We found that luminescence was emitted from water during proton irradiation and thought this phenomenon could be used for estimating the dose distribution. Methods: For this purpose, we placed water phantoms set on a table with a spot-scanning proton-therapy system, and luminescence images of these phantoms were measured with a high-sensitivity cooled charge coupled device (CCD) camera during proton-beam irradiation. We also conducted the imaging of phantoms of pure-water, fluorescein solution and acrylic block. We made three dimensional images from the projection data. Results: The luminescence images of water phantoms during the proton-beam irradiations showed clear Bragg peaks, and the measured proton ranges from the images were almost the same as those obtained with an ionization chamber. The image of the pure-water phantom also showed almost the same distribution as the tap-water phantom, indicating that the luminescence image was not related to impurities in the water. The luminescence image of fluorescein solution had ∼3 times higher intensity than water, with the same proton range as that of water. The luminescence image of the acrylic phantom had 14.5% shorter proton range than that of water; the proton range in the acrylic phantom was relatively matched with the calculated value. The luminescence images of the tap-water phantom during proton irradiation could be obtained in less than 2 sec. Three dimensional images were successfully obtained which have more quantitative information. Conclusion: Luminescence imaging during proton-beam irradiation has the potential to be a new method for range estimations in proton therapy.

Luminescent determination of trace amounts of terbium using diantipyrylmethane and salicylic acid

Energy Technology Data Exchange (ETDEWEB)

Tishchenko, M A; Gerasimenko, G I; Poluehktov, N S [AN Ukrainskoj SSR, Odessa. Inst. Obshchej i Neorganicheskoj Khimii

1978-01-01

To elucidate the possibility of using pyrazolone-5-diantipyril-methane (DAM) derivative for determination of terbium microimpurities, the conditions have been studied of luminescent determination of terbium in complex compounds containing an ion of rare-earth element, diantipyrilmethane, and salicylic acid (Sal.). The ratio between the components in the complex REE-DAM-Sal is 1:1:3. La, Y, Gd do not affect the luminescence intensity of terbium complex. A luminescent method of determining terbium traces in highly pure oxides of lanthanum, gadolinium, lutetium, and yttrium has been developed in which suspensions of complex precipitation are used. The amount of terbium determined in oxide of lanthanum, gadolinium, and lutetium is (1-5)x10/sup -6/% and (2-3)x10/sup -5/% in yttrium oxide.

Novel Luminescent Probe Based on a Terbium(III) Complex for Hemoglobin Determination

Science.gov (United States)

Yegorova, A. V.; Leonenko, I. I.; Aleksandrova, D. I.; Scrypynets, Yu. V.; Antonovich, V. P.; Ukrainets, I. V.

2014-09-01

We have studied the spectral luminescent properties of Tb(III) and Eu(III) complexes with a number of novel derivatives of oxoquinoline-3-carboxylic acid amides (L1-L5 ). We have observed quenching of the luminescence of 1:1 Tb(III)-L1-5 complexes by hemoglobin (Hb), which is explained by resonance energy transfer of electronic excitation from the donor (Tb(III)-L1-5 ) to the acceptor (Hb). Using the novel luminescent probe Tb(III)-L1, we have developed a method for determining Hb in human blood. The calibration Stern-Volmer plot is linear in the Hb concentration range 0.6-36.0 μg/mL, detection limit 0.2 μg/mL (3·10-9 mol/L).

Optically stimulated luminescence (OSL) and some other luminescence images from granite slices exposed with radiations

International Nuclear Information System (INIS)

Hashimoto, T.; Notoya, S.; Ojima, T.; Hoteida, M.

1995-01-01

Optically stimulated luminescence (OSL) images of some X- and γ-irradiated granite slices were obtained using photon detection through a 570 nm bandpass filter with diode-laser excitation of 910 nm. Alternative photo-induced phosphorescence (PIP) images, which were colour photographed immediately after the sunlight exposure of slice samples, were also found to be helpful in the observation of the luminescence properties and to filter selection for OSL measurements. These OSL and PIP images were compared with some other colour luminescence images, including thermoluminescence images (TLCI) and after-glow images (AGCI). It was obvious that there exists a variety of coloured emissions derived mainly from feldspar constituents and these were found to be dependent on the geological history or metamorphism of the granites. (Author)

The exploration and characterization of an orange emitting long persistent luminescence phosphor LiSr4(BO3)3:Eu2+

International Nuclear Information System (INIS)

Jin, Yahong; Hu, Yihua; Wu, Haoyi; Chen, Li; Wang, Xiaojuan

2016-01-01

An orange emitting long persistent phosphor LiSr 4 (BO 3 ) 3 :Eu 2+ was prepared successfully using a conventional solid state reaction method. The luminescent and persistent luminescence properties were studied using fluorescence spectra, decay curves, persistent luminescence spectra and thermoluminescence (TL) glow curves. The effects on the fluorescence and persistent luminescence properties by the dosage of Li 2 CO 3 were explored. The relationship between the Eu 2+ contents and persistent luminescence properties were studied. The optimal doping concentration of Eu 2+ was experimentally to be 1 mol%. The detailed processes and a possible mechanism were also discussed. - Highlights: • Li 2 CO 3 plays a critical role in producing persistent luminescence. • 40 % excess of Li 2 CO 3 makes the largest enhancement on persistent luminescence. • The optimal doping concentration of Eu 2+ was experimentally to be 1mol %. • Possible mechanism for persistent luminescence was discussed.

Luminescence optically stimulated: theory and applications

International Nuclear Information System (INIS)

Rivera M, T.; Azorin N, J.

2002-01-01

The thermally stimulated luminescence (Tl) has occupied an important place in the Solid state physics (FES) by the flexibility of the phenomena, mainly for its applications in the fields of Radiation Physics (FR) and Medical Physics (MF). The reason of this phenomena lies in the fact of the electrons release by the action of heat. Under that same reason, it can be used the action of another stimulant agent for releasing the trapped electrons in the metastable states (EM), this agent is the light which has the same effect that the heat, giving as result the production of light photons at using light in the visible spectra, of different wavelength that the excitation light. This phenomena is called Luminescence optically stimulated (LOE). The LOE has a great impact in the Solid State Physics (FES), dating and now in the use of the phenomena as a dosimetric method, alternate to the Tl, for its use in the ionizing and non-ionizing radiations fields. (Author)

Luminescence enhancement in irradiated polyethylene

International Nuclear Information System (INIS)

Charlesby, A.; Owen, G.P.

1976-01-01

Results are presented for the luminescence decay in polyethylene following irradiation at liquid nitrogen temperature and its enhancement on application of an electric field. It is found that both the luminescence enhancement and its subsequent decay may be described by a model involving electron tunnelling from a monoenergetic trap distribution to the parent positive ion. The possible nature of the trap is briefly discussed. (author)

Investigation of cross talk in single grain luminescence measurements using an EMCCD camera

International Nuclear Information System (INIS)

Gribenski, Natacha; Preusser, Frank; Greilich, Steffen; Huot, Sebastien; Mittelstraß, Dirk

2015-01-01

Highly sensitive electron multiplying charges coupled devices (EMCCD) enable the spatial detection of luminescence emissions from samples and have a high potential in single grain luminescence dating. However, the main challenge of this approach is the potential effect of cross talk, i.e. the influence of signal emitted by neighbouring grains, which will bias the information recorded from individual grains. Here, we present the first investigations into this phenomenon when performing single grain luminescence measurements of quartz grains spread over the flat surface of a sample carrier. Dose recovery tests using mixed populations show an important effect of cross talk, even when some distance is kept between grains. This issue is further investigated by focusing just on two grains and complemented by simulated experiments. Creation of an additional rejection criteria based on the brightness properties of the grains is inefficient in selecting grains unaffected by their surroundings. Therefore, the use of physical approaches or image processing algorithms to directly counteract cross talk is essential to allow routine single grain luminescence dating using EMCCD cameras. - Highlights: • We have performed single grain OSL measurements using an EMCCD detector. • Individual equivalent dose cannot be accurately recovered from a mixed dose population. • Grains are influenced by signal emitted by their neighbours during the measurements. • Simulated data confirm the strong effect of this phenomenon. • Increasing the distance between grains or applying brightness criteria are inefficient.

SrAl2O4:Eu2+ (1%) luminescence under UV, VUV and electron beam excitation

Science.gov (United States)

Nazarov, M.; Mammadova, S.; Spassky, D.; Vielhauer, S.; Abdullayeva, S.; Huseynov, A.; Jabbarov, R.

2018-01-01

This paper reports the luminescence properties of nanosized SrAl2O4:Eu2+ (1%) phosphors. The samples were prepared by combustion method at 600 °C, followed by annealing of the resultant combustion ash at 1000 °C in a reductive (Ar + H2) atmosphere. X-ray diffraction (XRD), photo luminescence (PL) and cathodoluminescence (CL) analysis and thermal stimulated luminescence (TSL) method were applied to characterize the phosphor. For the first time a peak at 375 nm was observed in CL spectra of SrAl2O4:Eu2+ (1%) nanophosphors. Luminescence excitation spectra analysis have shown that this peak is related to crystal defects. Also in TSL curve one strong peak was observed in the region above room temperature (T = 325 K), which is attributed to lattice defects, namely oxygen vacancies. A green LED was fabricated by the combination of the SrAl2O4:Eu2+ (1%) nanosized phosphor and a 365 nm UV InGaN chip.

Luminescence dating and palaeomagnetic age constraint on hominins from Sima de los Huesos, Atapuerca, Spain.

Science.gov (United States)

Arnold, Lee J; Demuro, Martina; Parés, Josep M; Arsuaga, Juan Luis; Aranburu, Arantza; Bermúdez de Castro, José María; Carbonell, Eudald

2014-02-01

Establishing a reliable chronology on the extensive hominin remains at Sima de los Huesos is critical for an improved understanding of the complex evolutionary histories and phylogenetic relationships of the European Middle Pleistocene hominin record. In this study, we use a combination of 'extended-range' luminescence dating techniques and palaeomagnetism to provide new age constraint on sedimentary infills that are unambiguously associated with the Sima fossil assemblage. Post-infrared-infrared stimulated luminescence (pIR-IR) dating of K-feldspars and thermally transferred optically stimulated luminescence (TT-OSL) dating of individual quartz grains provide weighted mean ages of 433 ± 15 ka (thousands of years) and 416 ± 19 ka, respectively, for allochthonous sedimentary horizons overlying the hominin-bearing clay breccia. The six replicate luminescence ages obtained for this deposit are reproducible and provide a combined minimum age estimate of 427 ± 12 ka for the underlying hominin fossils. Palaeomagnetic directions for the luminescence dated sediment horizon and underlying fossiliferous clays display exclusively normal polarities. These findings are consistent with the luminescence dating results and confirm that the hominin fossil horizon accumulated during the Brunhes Chron, i.e., within the last 780 ka. The new bracketing age constraint for the Sima hominins is in broad agreement with radiometrically dated Homo heidelbergensis fossil sites, such as Mauer and Arago, and suggests that the split of the H. neanderthalensis and H. sapiens lineages took place during the early Middle Pleistocene. More widespread numerical dating of key Early and Middle Pleistocene fossil sites across Europe is needed to test and refine competing models of hominin evolution. The new luminescence chronologies presented in this study demonstrate the versatility of TT-OSL and pIR-IR techniques and the potential role they could play in helping to refine evolutionary

A microemulsion preparation of nanoparticles of europium in silica with luminescence enhancement using silver

International Nuclear Information System (INIS)

Ma Zhiya; Dosev, Dosi; Kennedy, Ian M

2009-01-01

A facile one-pot microemulsion method has been developed for the synthesis of spherical silver core-silica shell (Ag-SiO 2 ) nanoparticles with europium chelates doped in the shell through a silane agent. The method is significantly more straightforward than other extant methods. Measurements of the luminescent emissions from the Ag-SiO 2 nanoparticles, in comparison with control silica nanoparticles without silver cores, showed that the presence of the silver cores can increase the fluorescence intensity approximately 24-fold and decrease the luminescence lifetime. This enhancement offers a potential increase in overall particle detectability with increased fluorophore photostability.

Luminescence dosimetry: recent developments in theory and applications

International Nuclear Information System (INIS)

McKeever, S.W.S.

2000-01-01

Thermally and optically stimulated luminescence have been used in applications in solid state physics, radiation dosimetry and geological dating for several decades. This paper gives a generalized description of these methods in terms of non-equilibrium thermodynamics and in doing so highlights similarities and differences between the methods. Recent advances in both the theory and application of the techniques are highlighted with numerous specific examples. (Author)

Luminescence spectroscopy of Rb2KTiOF5 oxyfluoride single crystals

Science.gov (United States)

Kozlov, A. V.; Pustovarov, V. A.; Sarychev, M. N.; Isaenko, L. I.

2017-09-01

Spectra of photoluminescence (PL) and X-ray excited luminescence (XRL) in region of 1.5-5.5 eV, PL excitation spectra using synchrotron radiation (3.7-22 eV), time-resolved impulse cathode-luminescence (ICL) spectra, the temperature depending of the XRL, decay kinetics as well as thermoluminescence curves were measured for single crystals Rb2KTiOF5, a promising nonlinear optical material. Single crystals are transparent in microwave, visible and near UV range, inter-band transition energy is Eg = 4.2 eV. Crystalline structure has two disordered mixed position O/F, phase transition in the region of 215 K. All the obtained results indicate that in luminescence spectra nonelementary band 2.2 eV is connected to the emission of self-trapped excitons. Nonelementary band 2.2 eV associated with the presence local distortion in the octahedron TiOF5. It is observed that at interband excitation in VUV region at energies more than 3.5 Eg the effect of multiplication of electronic excitations appears. That determines the high output of XRL and ICL. Luminescence methods of quality control of grown crystals are proposed.

Optimising the separation of quartz and feldspar optically stimulated luminescence using pulsed excitation

International Nuclear Information System (INIS)

Ankjaergaard, C.; Jain, M.; Thomsen, K.J.; Murray, A.S.

2010-01-01

In luminescence dating, the two most commonly used natural minerals, quartz and feldspar, are exposed to different dose rates in the natural environment, and so record different doses. The luminescence signals also have different stabilities. For accurate dosimetry, the signals from these two minerals must be separated, either by physical separation of the mineral grains, or by instrumental separation of the luminescence signals. The luminescence signals from quartz and feldspar have different luminescence lifetimes under pulsed optical stimulation. This difference in lifetime can be used to discriminate between the two signals from a mixed quartz-feldspar sample. The purpose of this study is to identify optimum measurement conditions for the best separation of quartz OSL from that of feldspar in a mixed sample using pulsed stimulation and time-resolved OSL. We integrate the signal from 5 μs after the LEDs are switched off until just before the LEDs are switched on again, with the pulse on-time equal to the pulse off-time of 50 μs. By using only the initial interval of the pulsed OSL decay curve (equivalent to 0.2 s of CW-OSL using blue light at 50 mW cm -2 ) we find that the quartz to feldspar pulsed OSL intensity ratio is at a maximum. By using these parameters with an additional infrared (IR) stimulation at 175 o C before measurement (to further reduce the feldspar signal intensity), we obtain a factor of 25 enhancement in signal separation compared to that from a conventional prior-IR CW measurement. This ratio can be further improved if the counting window in the pulse off-time is restricted to detect between 20 and 50 μs instead of the entire off-period.

Dosimetry based on thermally and optically stimulated luminescence

Energy Technology Data Exchange (ETDEWEB)

Agersnap Larsen, Niels

1999-01-01

Thermally Stimulated Luminescence (TL) and Optically Stimulated Luminescence (OSL) properties of quartz and {alpha}-Al{sub 2}O{sub 3} have been investigated. Anneling-induced OSL and TL sensitivity changes in quartz has been investigated by experiments and modelling. This study does not support a pre-dose effect to account for the observed annealing-induced sensitivity change. The experimental data indicates a more simple mechanism that involves alteration of the concentration of the defect centers. Results from modelling of removal or creation of defect centers comparing well with experimentally obtained data. Thermal quenching of luminescence for the main emission center, the F-center, in {alpha}-Al{sub 2}O{sub 3}:C has been investigated by analysing TL curves obtained at different heating rates. The thermal quenching dependence of luminescence is found to follow the classical Mott-Seitz expression. Basic investigations of OSL properties of {alpha}Al{sub 2}O{sub 3}:C, including: the thermal depth of the OSL traps, the temperature dependence of OSL, and the OSL stimulation spectra. Simultaneous measurements of TL and thermally stimulated conductivity (TSC) are presented for {gamma}-irradiated {alpha}Al{sub 2}O{sub 3}:C. Activation energy analysis of the data reveals a superposition of several first-order TL and TSC peaks caused by release of charge carriers from a distribution of trapping states. Furthermore a description of an experimental method developed to determine the sign of the thermally released charge carriers has been presented. (au) 8 tabs., 59 ills., 90 refs.

Cleavage Luminescence from Cleaved Indium Phosphide

International Nuclear Information System (INIS)

Dong-Guang, Li

2008-01-01

We outline the experiments performed to gain further information about the structure and properties of cleaved InP surfaces. The experiments involved detecting the luminescence produced after cleaving thin InP plates within a high vacuum, by a process of converting the luminescence to an electrical signal which could be amplified and measured accurately. The experimental results show that the detected luminescence durations from cleaved InP are usually only about 10μs. It is believed that this time represents the time of travel of the crack with the actual recombination time being much shorter. Strong signals could also be picked up from cleaved InP in air

Luminescent converter of neodymium laser radiation

International Nuclear Information System (INIS)

Ryba-Romanowski, W.; Golab, S.

1992-01-01

The new luminescent converter of neodymium laser radiation has been worked out. Activated inorganic compounds of ytterbium and erbium ions has been used as luminescent agent. The multi-component inorganic glass containing tellurium oxide as well as boron, sodium, magnesium and zinc oxides has been applied as a converter matrix

Identification of yellow luminescence centers in Be-doped GaN through pressure-dependent studies

Science.gov (United States)

Teisseyre, Henryk; Lyons, John L.; Kaminska, Agata; Jankowski, Dawid; Jarosz, Dawid; Boćkowski, Michał; Suchocki, Andrzej; Van de Walle, Chris G.

2017-06-01

Effective acceptor doping of wide-band-gap semiconductors is still an outstanding problem. Beryllium has been suggested as a shallow acceptor in GaN, but despite sporadic announcements, Be-induced p-type doping has never been practically realized. Be-doped GaN possesses two luminescence bands; one at 3.38 eV and a second near 2.2 eV at an energy close to that of the parasitic yellow luminescence often found in undoped GaN crystals. We have performed high hydrostatic pressure studies of bulk, Be-doped gallium nitride crystals using the diamond anvil cell technique. We observed a splitting of the yellow luminescence line under hydrostatic pressure into two components, one which is strongly dependent on applied pressure and another whose pressure dependence is more modest. Together with hybrid functional calculations, we attribute the strongly-varying component to the beryllium-oxygen complex. The second component of the yellow luminescence possesses very similar pressure behavior to the yellow luminescence observed in undoped samples grown by the same method, behavior which we find consistent with the CN acceptor. At higher pressure, we observe the vanishing of yellow luminescence and a rapid increase in luminescence intensity of the UV line. We explain this as the pressure-induced transformation of the Be-O complex from a highly localized state with large lattice relaxation to a delocalized state with limited lattice relaxation.

Cone beam x-ray luminescence computed tomography: a feasibility study.

Science.gov (United States)

Chen, Dongmei; Zhu, Shouping; Yi, Huangjian; Zhang, Xianghan; Chen, Duofang; Liang, Jimin; Tian, Jie

2013-03-01

The appearance of x-ray luminescence computed tomography (XLCT) opens new possibilities to perform molecular imaging by x ray. In the previous XLCT system, the sample was irradiated by a sequence of narrow x-ray beams and the x-ray luminescence was measured by a highly sensitive charge coupled device (CCD) camera. This resulted in a relatively long sampling time and relatively low utilization of the x-ray beam. In this paper, a novel cone beam x-ray luminescence computed tomography strategy is proposed, which can fully utilize the x-ray dose and shorten the scanning time. The imaging model and reconstruction method are described. The validity of the imaging strategy has been studied in this paper. In the cone beam XLCT system, the cone beam x ray was adopted to illuminate the sample and a highly sensitive CCD camera was utilized to acquire luminescent photons emitted from the sample. Photons scattering in biological tissues makes it an ill-posed problem to reconstruct the 3D distribution of the x-ray luminescent sample in the cone beam XLCT. In order to overcome this issue, the authors used the diffusion approximation model to describe the photon propagation in tissues, and employed the sparse regularization method for reconstruction. An incomplete variables truncated conjugate gradient method and permissible region strategy were used for reconstruction. Meanwhile, traditional x-ray CT imaging could also be performed in this system. The x-ray attenuation effect has been considered in their imaging model, which is helpful in improving the reconstruction accuracy. First, simulation experiments with cylinder phantoms were carried out to illustrate the validity of the proposed compensated method. The experimental results showed that the location error of the compensated algorithm was smaller than that of the uncompensated method. The permissible region strategy was applied and reduced the reconstruction error to less than 2 mm. The robustness and stability were then

Optically stimulated luminescence dating as a tool for calculating sedimentation rates in Chinese loess: comparisons with grain-size records

DEFF Research Database (Denmark)

Stevens, Thomas; Lu, HY

2009-01-01

Understanding loess sedimentation rates is crucial for constraining past atmospheric dust dynamics, regional climatic change and local depositional environments. However, the derivation of loess sedimentation rates is complicated by the lack of available methods for independent calculation......) the influences on sediment grain-size and accumulation; and (ii) their relationship through time and across the depositional region. This uncertainty has led to the widespread use of assumptions concerning the relationship between sedimentation rate and grain-size in order to derive age models and climate...... reconstructions. To address this uncertainty, detailed independent age models, based on optically stimulated luminescence dating, undertaken at 10 to 40 cm intervals at five sections across the Loess Plateau in China, have been used to calculate sedimentation rates and make comparisons with grain-size changes...

Chemisorptive luminescence on γ-irradiated magnesium oxide

International Nuclear Information System (INIS)

Breakspere, R.J.; Read, R.L.

1976-01-01

The intensity of a chemisorptive luminescence produced on MgO by oxygen at room temperature is increased by prior γ-irradiation of the MgO, under vacuum, before adsorption. This enhancement of the luminescence increases with radiation dose up to 1.9 x 10 6 rad and is attributed to the interaction between the F + sub (s) centres produced by the radiation and oxygen molecules arriving at the surface from the gas phase. In this work, the spectrum of the emitted luminescence could not be measured. (author)

Study of the absorption and energy transfer processes in inorganic luminescent materials in the UV and VUV region; Etude des processus d`absorption et de transfert d`energie au sein de materiaux inorganiques luminescents dans le domaine UV et VUV

Energy Technology Data Exchange (ETDEWEB)

Mayolet, A

1995-11-29

In order to find a green emitting phosphor showing high quantum efficiency and a short decay time which can be used in the color Plasma Display Panels developed by Thomson-TTE-TIV company, a VUV spectrophotometer built at IPN Orsay, using the synchrotron radiation from the SUPER-ACO storage ring as an excitation source, allow us the simultaneous recording of the luminescence excitation and diffuse reflectivity spectra of the inorganic compounds in the UV-VUV range. In addition, this experimental set-up enable us to determine the luminescence quantum efficiency of phosphors in the whole energy range of investigation. The chemical synthesis of rare-earth ortho-- and metaborate and rare-earth ortho- and metaphosphate doped with trivalent lanthanide ions cerium, praseodymium, europium and terbium have been made. The energy variation of the thresholds of the luminescence excitation mechanisms in function of the nature and the structure of the host matrix is discussed. We have determined the influence of the nephelauxetic effect and the crystal field intensity on the energy of the f-d inter-configuration transitions. The variation of the luminescence quantum efficiency of the dopant ion is interpreted through the `impurity bound exciton` model. The systematic comparison of the cerium and terbium trivalent ions spectroscopic properties in the Y(AG)G host lattice series stands to reason that the self-ionized state of the luminescent center plays an important role in the rate of the non radiative relaxation. It is the redox power of the host matrix which imposes to the luminescent center, the energy of this state. (author) 134 refs.

Europium enabled luminescent nanoparticles for biomedical applications

Energy Technology Data Exchange (ETDEWEB)

Syamchand, S.S., E-mail: syamchand.ss@gmail.com; Sony, G., E-mail: emailtosony@gmail.com

2015-09-15

Lanthanide based nanoparticles are receiving great attention ought to their excellent luminescent and magnetic properties and find challenging biomedical applications. Among the luminescent lanthanide NPs, europium based NPs (Eu-NPs) are better candidates for immunoassay and imaging applications. The Eu-NPs have an edge over quantum dots (QDs) by means of their stable luminescence, long fluorescence lifetime, sharp emission peaks with narrow band width, lack of blinking and biocompatibility. This review surveys the synthesis and properties of a variety of Eu-NPs consolidated from different research articles, for their applications in medicine and biology. The exquisite luminescent properties of Eu-NPs are explored for developing biomedical applications such as immunoassay and bioimaging including multimodal imaging. The biomedical applications of Eu-NPs are mostly diagnostic in nature and mainly focus on various key analytes present in biological systems. The luminescent properties of europium enabled NPs are influenced by a number of factors such as the site symmetry, the metal nanoparticles, metal ions, quantum dots, surfactants, morphology of Eu-NPs, crystal defect, phenomena like antenna effect and physical parameters like temperature. Through this review we explore and assimilate all the factors which affect the luminescence in Eu-NPs and coil a new thread of parameters that control the luminescence in Eu-NPs, which would provide further insight in developing Eu-based nanoprobes for future biomedical prospects. - Highlights: • The review describes 14 major factors that influence the luminescence properties of europium enabled luminescent nanoparticles (Eu-NPs). • Surveys different types of europium containing nanoparticles that have been reported for their biomedical applications. • Eu-NPs are conveniently divided into four different categories, based on the type of the substrates involved. The four categories are (1) virgin Eu-substrate based NPs; (2

Europium enabled luminescent nanoparticles for biomedical applications

International Nuclear Information System (INIS)

Syamchand, S.S.; Sony, G.

2015-01-01

Lanthanide based nanoparticles are receiving great attention ought to their excellent luminescent and magnetic properties and find challenging biomedical applications. Among the luminescent lanthanide NPs, europium based NPs (Eu-NPs) are better candidates for immunoassay and imaging applications. The Eu-NPs have an edge over quantum dots (QDs) by means of their stable luminescence, long fluorescence lifetime, sharp emission peaks with narrow band width, lack of blinking and biocompatibility. This review surveys the synthesis and properties of a variety of Eu-NPs consolidated from different research articles, for their applications in medicine and biology. The exquisite luminescent properties of Eu-NPs are explored for developing biomedical applications such as immunoassay and bioimaging including multimodal imaging. The biomedical applications of Eu-NPs are mostly diagnostic in nature and mainly focus on various key analytes present in biological systems. The luminescent properties of europium enabled NPs are influenced by a number of factors such as the site symmetry, the metal nanoparticles, metal ions, quantum dots, surfactants, morphology of Eu-NPs, crystal defect, phenomena like antenna effect and physical parameters like temperature. Through this review we explore and assimilate all the factors which affect the luminescence in Eu-NPs and coil a new thread of parameters that control the luminescence in Eu-NPs, which would provide further insight in developing Eu-based nanoprobes for future biomedical prospects. - Highlights: • The review describes 14 major factors that influence the luminescence properties of europium enabled luminescent nanoparticles (Eu-NPs). • Surveys different types of europium containing nanoparticles that have been reported for their biomedical applications. • Eu-NPs are conveniently divided into four different categories, based on the type of the substrates involved. The four categories are (1) virgin Eu-substrate based NPs; (2

Verification of the causes of glaciations and sea level changes using the records of calcite speleothems.

Directory of Open Access Journals (Sweden)

Shopov Yavor Y.

2000-01-01

Full Text Available The luminescence of calcite speleothems displays an exponential dependence on soil temperature unless there is a dense cover of forest over the cave to dampen it. This relationship is determined primarily by the strength of solar visible and infrared radiation. It is suggested that, as a consequence, the microzonal variations of luminescence often found in speleothems can be used as a proxy index of Solar Insolation. The luminescence solar insolation proxy record of a speleothem from Jewel Cave, South Dakota, USA, was found to display millenial and centennial cycles in the record. It exhibits a rapid increase in solar insolation at 139 ± 5.5 kyrs. This increase precedes that suggested by the Orbital theory by about 10,000 years and is due to superimposition of the most powerful cycle in solar luminosity of 11.5 kyrs, upon the curve of orbital variations. The record from a speleothem in Duhlata Cave, Bulgaria matches that of South Dakota within the limits of dating error, indicating that both of these records (which are 10,000 km apart measure global solar insolation controls rather than local paleotemperature variations.

Luminescent properties of fluorophosphate glasses with lead chalcogenides molecular clusters

International Nuclear Information System (INIS)

Kolobkova, E.V.; Kukushkin, D.S.; Nikonorov, N.V.; Shakhverdov, T.A.; Sidorov, A.I.; Vasiliev, V.N.

2015-01-01

Fluorophosphate glasses containing lead, selenium, and sulfur exhibit an intense luminescence in the 400–620 nm spectral region when excited by the 240–420 nm radiation. This luminescence is due to the presence of (PbSe) n and/or (PbS) n molecular clusters in the glasses, which appear in the as-prepared glasses before quantum dots formation. The thermal treatment at temperatures less than the glass transition temperature results in the red-shift of the luminescence bands and in an increase in the luminescence intensity. Heating the thermally treated glass samples leads to the reversible thermal quenching of the luminescence. - Highlights: • Fluorophosphate glasses with Pb, Se, and S ions contain (PbSe) n or (PbS) n molecular clusters. • (PbSe) n and (PbS) n molecular clusters possess luminescence in the visible with UV excitation. • Heating the glass leads to the reversible thermal quenching of the luminescence

Visible luminescence in polyaniline/(gold nanoparticle) composites

Energy Technology Data Exchange (ETDEWEB)

Santos, Renata F. S. [Universidade Federal de Pernambuco, Pos-Graduacao em Ciencia de Materiais (Brazil); Andrade, Cesar A. S. [Universidade Federal de Pernambuco, Departamento de Bioquimica (Brazil); Santos, Clecio G. dos [Instituto de Educacao, Ciencia e Tecnologia de Pernambuco (Brazil); Melo, Celso P. de, E-mail: celso@df.ufpe.br [Universidade Federal de Pernambuco, Pos-Graduacao em Ciencia de Materiais (Brazil)

2013-01-15

We describe the use of solution chemistry methods to prepare polyaniline/(gold nanoparticles)-PANI/AuNPs-composites as colloidal particles that exhibit an intense green fluorescence after excitation in the ultraviolet region. Measurements of the relative fluorescence quantum yield indicate that the intensity of the observed luminescence of these nanocomposites is a few orders of magnitude higher than the corresponding fluorescence of either the isolated polymer or the pure AuNPs. Hence, cooperative effects between the conducting polymer chains and the metallic particles must dominate the emission behavior of these materials. Transmission electron microscopy reveals the existence of metal nanoparticle aggregates with sizes in the 2-3 nm range dispersed in the polymer matrix. By implementing an experimental planning, we have been able to change the preparation parameters so as to vary in a controlled manner the intensity and the profile of the luminescence spectrum as well as the size and aggregation characteristics of the colloidal particles. We also show that when the pH of the medium is varied, the dielectric properties (such as the degree of conductivity) of the PANI/AuNPs colloidal solutions and the intensity of their luminescence change in a consistent manner. Due to the polycation nature of the doped PANI chains, we suggest that these composites may find interesting applications as fluorescent markers of biologic molecules.

Luminescent polymethyl methacrylate modified by gamma radiation

International Nuclear Information System (INIS)

Morais, Guilherme F.; Forster, Pedro L.; Marchini, Leonardo G.; Lugao, Ademar B.; Parra, Duclerc F.

2011-01-01

Thin films of PMMA (polymethyl methacrylate) doped with luminescent complexes have been studied and developed for applications in advanced technologies. The problem of stability of these films is focused in this study. Films stabilization by reaction with fluorinated monomers is a recent study that aims to increase its luminescence properties for long time. The films were prepared by dilution of PMMA in chloroform with addition of europium complex, at proportion of 5% by weight of polymer. The luminescent polymer films were obtained by casting. Thin layer slides of the film were separated in three parts. One was reacted with fluorinated monomers (C 2 F 4 ) in closed reactor for 48 hours. A second part was reacted with C 2 F 4 after irradiation in gamma source at 5 kGy in simultaneous process. The last part was used as obtained. The luminescent polymer matrices were characterized using the techniques of infrared (FTIR) and thermogravimetry (TGA/DTG). Samples of the films were, in presence of fluorine monomers, exposed to ionizing radiation in dose of 5 kGy, for react with monomers in the doped polymer surface. In this case the effects of radiation were evaluated on the luminescent films. (author)

Zero-reabsorption doped-nanocrystal luminescent solar concentrators.

Science.gov (United States)

Erickson, Christian S; Bradshaw, Liam R; McDowall, Stephen; Gilbertson, John D; Gamelin, Daniel R; Patrick, David L

2014-04-22

Optical concentration can lower the cost of solar energy conversion by reducing photovoltaic cell area and increasing photovoltaic efficiency. Luminescent solar concentrators offer an attractive approach to combined spectral and spatial concentration of both specular and diffuse light without tracking, but they have been plagued by luminophore self-absorption losses when employed on practical size scales. Here, we introduce doped semiconductor nanocrystals as a new class of phosphors for use in luminescent solar concentrators. In proof-of-concept experiments, visibly transparent, ultraviolet-selective luminescent solar concentrators have been prepared using colloidal Mn(2+)-doped ZnSe nanocrystals that show no luminescence reabsorption. Optical quantum efficiencies of 37% are measured, yielding a maximum projected energy concentration of ∼6× and flux gain for a-Si photovoltaics of 15.6 in the large-area limit, for the first time bounded not by luminophore self-absorption but by the transparency of the waveguide itself. Future directions in the use of colloidal doped nanocrystals as robust, processable spectrum-shifting phosphors for luminescent solar concentration on the large scales required for practical application of this technology are discussed.

Luminescence imaging of water during irradiation of X-ray photons lower energy than Cerenkov- light threshold

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, Seiichi; Koyama, Shuji; Komori, Masataka [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine (Japan); Toshito, Toshiyuki [Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya City West Medical Center (Japan)

2016-10-01

Luminescence imaging of water using X-ray photon irradiation at energy lower than maximum energy of ~200 keV is thought to be impossible because the secondary electrons produced in this energy range do not emit Cerenkov- light. Contrary to this consensus assumption, we show that the luminescence imaging of water can be achieved by X-ray irradiation at energy lower than 120 keV. We placed water phantoms on a table with a conventional X-ray imaging system, and luminescence images of these phantoms were measured with a high-sensitivity, cooled charge coupled device (CCD) camera during X-ray photon irradiation at energy below 120 keV. We also carried out such imaging of an acrylic block and plastic scintillator. The luminescence images of water phantoms taken during X-ray photon irradiation clearly showed X-ray photon distribution. The intensity of the X-ray photon images of the phantom increased almost proportionally to the number of X-ray irradiations. Lower-energy X-ray photon irradiation showed lower-intensity luminescence at the deeper parts of the phantom due to the higher X-ray absorption in the water phantom. Furthermore, lower-intensity luminescence also appeared at the deeper parts of the acrylic phantom due to its higher density than water. The intensity of the luminescence for water was 0.005% of that for plastic scintillator. Luminescence imaging of water during X-ray photon irradiation at energy lower than 120 keV was possible. This luminescence imaging method is promising for dose estimation in X-ray imaging systems.

Luminescence imaging of water during irradiation of X-ray photons lower energy than Cerenkov- light threshold

Science.gov (United States)

Yamamoto, Seiichi; Koyama, Shuji; Komori, Masataka; Toshito, Toshiyuki

2016-10-01

Luminescence imaging of water using X-ray photon irradiation at energy lower than maximum energy of 200 keV is thought to be impossible because the secondary electrons produced in this energy range do not emit Cerenkov- light. Contrary to this consensus assumption, we show that the luminescence imaging of water can be achieved by X-ray irradiation at energy lower than 120 keV. We placed water phantoms on a table with a conventional X-ray imaging system, and luminescence images of these phantoms were measured with a high-sensitivity, cooled charge coupled device (CCD) camera during X-ray photon irradiation at energy below 120 keV. We also carried out such imaging of an acrylic block and plastic scintillator. The luminescence images of water phantoms taken during X-ray photon irradiation clearly showed X-ray photon distribution. The intensity of the X-ray photon images of the phantom increased almost proportionally to the number of X-ray irradiations. Lower-energy X-ray photon irradiation showed lower-intensity luminescence at the deeper parts of the phantom due to the higher X-ray absorption in the water phantom. Furthermore, lower-intensity luminescence also appeared at the deeper parts of the acrylic phantom due to its higher density than water. The intensity of the luminescence for water was 0.005% of that for plastic scintillator. Luminescence imaging of water during X-ray photon irradiation at energy lower than 120 keV was possible. This luminescence imaging method is promising for dose estimation in X-ray imaging systems.

Oxide/polymer nanocomposites as new luminescent materials

Science.gov (United States)

Vollath, D.; Szabó, D. V.; Schlabach, S.

2004-06-01

It is demonstrated that nanocomposites, consisting of an electrically insulating oxide core and PMMA coating exhibit strong luminescence. This luminescence is connected to the interface, where PMMA is bond via a carboxylate bonding to the surface. In this case, luminescence is originated at the carbonyl group of the coating polymer. With decreasing particle size, this emission shows a blue shift, following a law inversely the ones found for quantum confinement systems. For semi-conducting oxides, such as ZnO, this interface related emission is found additionally to quantum confinement phenomena.

Study of the absorption and energy transfer processes in inorganic luminescent materials in the UV and VUV region

International Nuclear Information System (INIS)

Mayolet, A.

1995-01-01

In order to find a green emitting phosphor showing high quantum efficiency and a short decay time which can be used in the color Plasma Display Panels developed by Thomson-TTE-TIV company, a VUV spectrophotometer built at IPN Orsay, using the synchrotron radiation from the SUPER-ACO storage ring as an excitation source, allow us the simultaneous recording of the luminescence excitation and diffuse reflectivity spectra of the inorganic compounds in the UV-VUV range. In addition, this experimental set-up enable us to determine the luminescence quantum efficiency of phosphors in the whole energy range of investigation. The chemical synthesis of rare-earth ortho-- and metaborate and rare-earth ortho- and metaphosphate doped with trivalent lanthanide ions cerium, praseodymium, europium and terbium have been made. The energy variation of the thresholds of the luminescence excitation mechanisms in function of the nature and the structure of the host matrix is discussed. We have determined the influence of the nephelauxetic effect and the crystal field intensity on the energy of the f-d inter-configuration transitions. The variation of the luminescence quantum efficiency of the dopant ion is interpreted through the 'impurity bound exciton' model. The systematic comparison of the cerium and terbium trivalent ions spectroscopic properties in the Y(AG)G host lattice series stands to reason that the self-ionized state of the luminescent center plays an important role in the rate of the non radiative relaxation. It is the redox power of the host matrix which imposes to the luminescent center, the energy of this state. (author)

Application of luminescence techniques in retrospective dosimetry

DEFF Research Database (Denmark)

Bøtter-Jensen, L.; Jungner, H.

1999-01-01

Luminescence signals measured from minerals within bricks or ceramic samples can provide information about the absorbed radiation dose. This feature has for several years been used in dating archaeological and geological samples and recently luminescence techniques have been intensively used far ...

Luminescence and the light emitting diode the basics and technology of leds and the luminescence properties of the materials

CERN Document Server

Williams, E W; Pamplin, BR

2013-01-01

Luminescence and the Light Emitting Diode: The Basics and Technology of LEDS and the Luminescence Properties of the Materials focuses on the basic physics and technology of light emitting diodes (LEDS) and pn junction lasers as well as their luminescence properties. Optical processes in semiconductors and the useful devices which can be made are discussed. Comprised of 10 chapters, this book begins with an introduction to the crystal structure and growth, as well as the optical and electrical properties of LED materials. The detailed fabrication of the LED is then considered, along with the lu

Identifying well-bleached quartz using the different bleaching rates of quartz and feldspar luminescence signals

DEFF Research Database (Denmark)

Murray, A.S.; Thomsen, Kristina Jørkov; Masuda, N.

2012-01-01

When dating older sedimentary deposits using quartz, there are no unambiguous methods for identifying the presence of incomplete bleaching. Current statistical analysis of dose distributions depends entirely on the assumption that incomplete bleaching and mixing are the main causes of any excess...... dispersion in the distribution; the only existing way to test this assumption is using independent age control. Here we suggest a new approach to this question, based on the differential bleaching rates of quartz and feldspar luminescence signals. We first present data that confirm the differences...... in relative bleaching rates of quartz optically stimulated luminescence (OSL) and feldspar luminescence stimulated at 50 °C by infrared light (IR50) and feldspar luminescence stimulated at 290 °C by infrared light after a stimulation at 50 °C (pIRIR290), and use recently deposited samples to determine...

Ratiometric Time-Gated Luminescence Probe for Nitric Oxide Based on an Apoferritin-Assembled Lanthanide Complex-Rhodamine Luminescence Resonance Energy Transfer System.

Science.gov (United States)

Tian, Lu; Dai, Zhichao; Liu, Xiangli; Song, Bo; Ye, Zhiqiang; Yuan, Jingli

2015-11-03

Using apoferritin (AFt) as a carrier, a novel ratiometric luminescence probe based on luminescence resonance energy transfer (LRET) between a Tb(3+) complex (PTTA-Tb(3+)) and a rhodamine derivative (Rh-NO), PTTA-Tb(3+)@AFt-Rh-NO, has been designed and prepared for the specific recognition and time-gated luminescence detection of nitric oxide (NO) in living samples. In this LRET probe, PTTA-Tb(3+) encapsulated in the core of AFt is the energy donor, and Rh-NO, a NO-responsive rhodamine derivative, bound on the surface of AFt is the energy acceptor. The probe only emits strong Tb(3+) luminescence because the emission of rhodamine is switched off in the absence of NO. Upon reaction with NO, accompanied by the turn-on of rhodamine emission, the LRET from Tb(3+) complex to rhodamine occurs, which results in the remarkable increase and decrease of the long-lived emissions of rhodamine and PTTA-Tb(3+), respectively. After the reaction, the intensity ratio of rhodamine emission to Tb(3+) emission, I565/I539, is ∼24.5-fold increased, and the dose-dependent enhancement of I565/I539 shows a good linearity in a wide concentration range of NO. This unique luminescence response allowed PTTA-Tb(3+)@AFt-Rh-NO to be conveniently used as a ratiometric probe for the time-gated luminescence detection of NO with I565/I539 as a signal. Taking advantages of high specificity and sensitivity of the probe as well as its good water-solubility, biocompatibility, and cell membrane permeability, PTTA-Tb(3+)@AFt-Rh-NO was successfully used for the luminescent imaging of NO in living cells and Daphnia magna. The results demonstrated the efficacy of the probe and highlighted it's advantages for the ratiometric time-gated luminescence bioimaging application.

Highly Sensitive Luminescence Assessment of Bile Acid Using a Balofloxacin-Europium(III) Probe in Micellar Medium

International Nuclear Information System (INIS)

Cai, Huan; Zhao, Fang; Si, Hailin; Zhang, Shuaishuai; Wang, Chunchun; Qi, Peirong

2012-01-01

A novel and simple method of luminescence enhancement effect for the determination of trace amounts of bile acid was proposed. The procedure was based on the luminescence intensity of the balofloxacin-europium(III) complex that could be strongly enhanced by bile acid in the presence of sodium dodecyl benzene sulfonate (SDBS). Under the optimum conditions, the enhanced luminescence intensity of the system exhibited a good linear relationship with the bile acid concentration in the range 5.0 Χ 10 -9 - 7.0 Χ 10 -7 mol L -1 with a detection limit of 1.3 Χ 10 -9 mol L.1 (3σ). The relative standard deviation (RSD) was 1.7% (n = 11) for 5.0 Χ 10 -8 mol L -1 bile acid. The applicability of the method to the determination of bile acid was demonstrated by investigating the effect of potential interferences and by analyzing human serum and urine samples. The possible enhancement mechanism of luminescence intensity in balofloxacin-europium(III)-bile acid-SDBS system was also discussed briefly

Novel Mechano-Luminescent Sensors Based on Piezoelectric/Electroluminescent Composites

Directory of Open Access Journals (Sweden)

Yunzhang Fang

2011-04-01

Full Text Available A high-sensitivity mechano-luminescent sensor was fabricated on the basis of piezoelectric/electroluminescent composites. The working principle of this mechano-luminescent sensor was elucidated by analyzing the relationship between the piezoelectric-induced charges and the electroluminescent effects. When a stress is applied on the piezoelectric layer, electrical charges will be induced at both the top and bottom sides of the piezoelectric layer. The induced electrical charges will lead to a light output from the electroluminescent layer, thus producing a mechano-luminescence effect. By increasing the vibration strength or frequency applied, the mechano-luminescence output can be obviously enhanced. Mechano-luminescence sensors have potential in smart stress-to-light devices, such as foot-stress-distribution-diagnosis systems and dynamic-load-monitors for bridge hanging cables.

Quantitative study of luminescence optical tomography. Application to sources localisation in molecular imaging

International Nuclear Information System (INIS)

Boffety, Matthieu

2010-01-01

Molecular imaging is a major modality in the field of preclinical research. Among the existing methods, techniques based on optical detection of visible or near infrared radiation are the most recent and are mainly represented by luminescence optical tomography techniques. These methods allow for 3D characterization of a biological medium by reconstructing maps of concentration or localisation of luminescent beacons sensitive to biological and chemical processes at the molecular or cellular scale. Luminescence optical tomography is based on a model of light propagation in tissues, a protocol for acquiring surface signal and a numerical inversion procedure used to reconstruct the parameters of interest. This thesis is structured around these three axes and provides an answer to each problem. The main objective of this study is to introduce and present the tools to evaluate the theoretical performances of optical tomography methods. One of its major outcomes is the realisation of experimental tomographic reconstructions from images acquired by an optical imager designed for 2D planar imaging and developed by the company Quidd. In a first step we develop the theory of transport in scattering medium to establish the concept on which our work will rely. We present two different propagation models as well as resolution methods and theoretical difficulties associated with them. In a second part we introduce the statistical tools used to characterise tomographic systems. We define and apply a procedure to simple situations in luminescence optical tomography. The last part of this work presents the development of an inversion procedure. After introducing the theoretical framework we validate the procedure from numerical data before successfully applying it to experimental measurements. (author) [fr

Increasing lanthanide luminescence by use of the RETEL effect.

Science.gov (United States)

Leif, Robert C; Vallarino, Lidia M; Becker, Margie C; Yang, Sean

2006-08-01

Luminescent lanthanide complexes produce emissions with the narrowest-known width at half maximum; however, their significant use in cytometry required an increase in luminescence intensity. The companion review, Leif et al., Cytometry 2006;69A:767-778, described a new technique for the enhancement of lanthanide luminescence, the Resonance Energy Transfer Enhanced Luminescence (RETEL) effect, which increases luminescence and is compatible with standard slide microscopy. The luminescence of the europium ion macrocyclic complex, EuMac, was increased by employing the RETEL effect. After adding the nonluminescent gadolinium ion complex of the thenoyltrifluoroacetonate (TTFA) ligand or the sodium salt of TTFA in ethanol solution, the EuMac-labeled sample was allowed to dry. Both a conventional arc lamp and a time-gated UV LED served as light sources for microscopic imaging. The emission intensity was measured with a CCD camera. Multiple time-gated images were summed with special software to permit analysis and effective presentation of the final image. With the RETEL effect, the luminescence of the EuMac-streptavidin conjugate increased at least six-fold upon drying. Nuclei of apoptotic cells were stained with DAPI and tailed with 5BrdUrd to which a EuMac-anti-5BrdU conjugate was subsequently attached. Time-gated images showed the long-lived EuMac luminescence but did not show the short-lived DAPI fluorescence. Imaging of DNA-synthesizing cells with an arc lamp showed that both S phase and apoptotic cells were labeled, and that their labeling patterns were different. The images of the luminescent EuMac and fluorescent DAPI were combined to produce a color image on a white background. This combination of simple chemistry, instrumentation, and presentation should make possible the inexpensive use of the lanthanide macrocycles, Quantum Dyes, as molecular diagnostics for cytological and histopathological microscopic imaging. (c) 2006 International Society for Analytical

Patterned dye structures limit reabsorption in luminescent solar concentrators

NARCIS (Netherlands)

Tsoi, S.; Broer, D.J.; Bastiaansen, C.W.M.; Debije, M.G.

2010-01-01

This work describes a method for limiting internal losses of a luminescent solar concentrator (LSC) due to reabsorption through patterning the fluorescent dye doped coating of the LSC. By engineering the dye coating into regular line patterns with fill factors ranging from 20 - 80%, the surface

Luminescence and circularly polarized luminescence of macrocyclic Eu(III) and Tb(III) complexes embedded in xerogel and sol-gel SiO2 glasses

International Nuclear Information System (INIS)

Morita, M.; Rau, D.; Kai, T.

2002-01-01

Luminescence, time-resolved luminescence, circularly polarized luminescence (CPL) and decay profiles of Ln(III)(15-crownether-5) (Ln=Ce, Sm, Eu, Tb) and Tb(III)-(R),(S)-cyclen derivative complexes doped in xerogel and sol-gel silica glasses are measured at temperatures down to 10 K to characterize luminescence properties and the electronic structure in the excited states. Luminescence spectral profiles and calculation of crystal field parameters (B 0 (2) ,B 2 (2) ) in the 5 D 0 → 7 F J (J=1,2) transition give evidence of the fact that the pentagonal and planar structure of Eu(III) (15-crownether-5) does hold in xerogel and sol-gel glasses prepared at temperatures below 100 deg. C. As annealing temperatures are increased from 80 deg. C to 750 deg. C, Eu(III) complexes in sol-gel glasses are found to decompose gradually to SiO 2 :Eu 3+ . Tb(III)-(R) and (S)-cyclen derivative complexes in xerogel reveal at room temperature and 10 K sharp CPL spectra with luminescence dissymmetry factors g lum =-0.1 and 0.1, respectively. These complexes doped in sol-gel glasses represent luminescence characteristics of rare earth ions encapsulated in the nano-porous host

Polymethylmethacrylate-based luminescent solar concentrators with bottom-mounted solar cells

International Nuclear Information System (INIS)

Zhang, Yi; Sun, Song; Kang, Rui; Zhang, Jun; Zhang, Ningning; Yan, Wenhao; Xie, Wei; Ding, Jianjun; Bao, Jun; Gao, Chen

2015-01-01

Graphical abstract: - Highlights: • Bottom-mounted luminescent solar concentrators on dye-doped plates were studied. • The mechanism of transport process was proposed. • The fabricated luminescent solar concentrator achieved a gain of 1.38. • Power conversion efficiency of 5.03% was obtained with cell area coverage of 27%. • The lowest cost per watt of $1.89 was optimized with cell area coverage of 18%. - Abstract: Luminescent solar concentrators offer an attractive approach to concentrate sunlight economically without tracking, but the narrow absorption band of luminescent materials hinders their further development. This paper describes bottom-mounted luminescent solar concentrators on dye-doped polymethylmethacrylate plates that absorb not only the waveguided light but also the transmitted sunlight and partial fluorescent light in the escape cone. A series of bottom-mounted luminescent solar concentrators with size of 78 mm × 78 mm × 7 mm were fabricated and their gain and power conversion efficiency were investigated. The transport process of the waveguided light and the relationship between the bottom-mounted cells were studied to optimize the performance of the device. The bottom-mounted luminescent solar concentrator with cell area coverage of 9% displayed a cell gain of 1.38, to our best knowledge, which is the highest value for dye-doped polymethylmethacrylate plate luminescent solar concentrators. Power conversion efficiency as high as 5.03% was obtained with cell area coverage of 27%. Furthermore, the bottom-mounted luminescent solar concentrator was found to have a lowest cost per watt of $1.89 with cell area coverage of 18%. These results suggested that the fabricated bottom-mounted luminescent solar concentrator may have a potential in low-cost building integrated photovoltaic application

20 years of speleothem paleoluminescence records of environmental changes: an overview

Directory of Open Access Journals (Sweden)

Shopov Yavor Y.

2004-12-01

Full Text Available This paper discusses advance of the research on Speleothem paleoluminescence Records of Environmental Changes after it have been first introduced by the author 20 years ago.It is demonstrated that most of the progress in this field was made in result of the operation of the International Program “Luminescence of Cave Minerals” of the commission on Physical Chemistry and Hydrogeology of Karst of UIS of UNESCO.Potential, resolution and limitations of high resolution luminescence speleothem proxy records of Paleotemperature, Solar Insolation, Solar Luminosity, Glaciations, Sea Level advances, Past Precipitation, Plants Populations, Paleosoils, Past Karst Denudation, Chemical Pollution, Geomagnetic field and Cosmic Rays Flux variations, Cosmogenic Isotopes production and Supernova Eruptions in the Past, Advances of Hydrothermal Waters, and Tectonic Uplift are discussed.It is demonstrated that speleothems allow extremely high resolution (higher than in any other paleoclimatic terrestrial archives and long duration of records. Some speleothems can be used as natural climatic stations for obtaining of quantitative proxy records of Quaternary climates with annual resolution.

A luminescence-optical spectroscopy study of Rb2KTiOF5 single crystals

Science.gov (United States)

Pustovarov, V. A.; Ogorodnikov, I. N.; Kozlov, A. V.; Isaenko, L. I.

2018-06-01

Large single crystals of Rb2KTiOF5 (RKTF), grown by slow solidification method, were studied (7-400 K) for various types of optical and radiation effects. The optical absorption spectra, the parameters of the Urbach rule at 293 K (σ = 0.24 and EU = 105 meV), the low-temperature reflection spectra (T = 7 K, E = 3.7-22 eV) were determined. The luminescence spectra (1.2-6.2 eV) and luminescence decay kinetics are studied upon excitation by a nanosecond electron beam (PCL), ultraviolet and vacuum ultraviolet light (PL), or X-rays radiation (XRL). PL excitation spectra under selective photoexcitation by synchrotron radiation (E = 3.7-22 eV, T = 7 K), temperature dependences of the intensity of steady-state XRL in different emission bands, as well as thermoluminescence (7-400 K) are studied. In the visible spectral region, we detected three luminescence bands that were attributed to radiative annihilation of intrinsic excitons (2.25 eV), recombination-type luminescence (2.1 eV) and luminescence of higher TiOF5 complexes (1.9 eV). The exponential component with lifetime of about 19 μs was revealed in the PCL decay kinetics at 2.25 eV. The low-energy onset of the intrinsic host absorption Ec = 3.55 eV was determined on the basis of the experimental data obtained. Spectra of optical constants were calculated by the Kramers-Krönig method, the energy of the onset of the interband transitions Eg = 4.2 eV was determined, and the main peaks of the optical spectra were identified.

Kinetics of infrared stimulated luminescence from feldspars

DEFF Research Database (Denmark)

Jain, Mayank; Sohbati, Reza; Guralnik, Benny

2015-01-01

thermal and optical, of the infrared stimulated luminescence signal from feldspar. Based on the application of this model, it is concluded that different infra-red stimulated luminescence emissions (UV, blue, yellow and far-red) follow the same kinetics, and, therefore, involve participation of the same...

Process for obtaining luminescent glass layers

International Nuclear Information System (INIS)

Heindi, R.; Robert, A.

1984-01-01

Process for obtaining luminescent glass layers, application to the production of devices provided with said layers and to the construction of photoscintillators. The process comprises projecting onto a support, by cathodic sputtering, the material of at least one target, each target including silica and at least one chemical compound able to give luminescent centers, such as a cerium oxide, so as to form at least one luminescent glass layer of the said support. The layer or layers formed preferably undergo a heat treatment such as annealing in order to increase the luminous efficiency thereof. It is in this way possible to form a scintillating glass layer on the previously frosted entrance window of a photomultiplier in order to obtain an integrated photoscintillator

NaCl samples for optical luminescence dosimetry

International Nuclear Information System (INIS)

Catli, S.

2005-01-01

Optically stimulated luminescence (OSL) have been used broadly for luminescence dosimetry and dating. In many cases, it has been pointed out that the decay of the OSL do not generally behave according to a simple exponential function. In this study the Infra-red stimulated luminescence (IRSL) intensity from NaCl samples were experimentally measured. The decay curves for this sample were fitted to some functions and it is in good agreement with the function y = α + b exp(-cx). The IRSL decay curves from NaCl using different β-doses have been obtained and investigated their dose response

Luminescent polymethyl methacrylate modified by gamma radiation

Energy Technology Data Exchange (ETDEWEB)

Morais, Guilherme F. [Faculdade de Tecnologia de Sao Paulo (FATEC-ZL), Sao Paulo, SP (Brazil); Forster, Pedro L.; Marchini, Leonardo G.; Lugao, Ademar B.; Parra, Duclerc F., E-mail: dfparra@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-07-01

Thin films of PMMA (polymethyl methacrylate) doped with luminescent complexes have been studied and developed for applications in advanced technologies. The problem of stability of these films is focused in this study. Films stabilization by reaction with fluorinated monomers is a recent study that aims to increase its luminescence properties for long time. The films were prepared by dilution of PMMA in chloroform with addition of europium complex, at proportion of 5% by weight of polymer. The luminescent polymer films were obtained by casting. Thin layer slides of the film were separated in three parts. One was reacted with fluorinated monomers (C{sub 2}F{sub 4}) in closed reactor for 48 hours. A second part was reacted with C{sub 2}F{sub 4} after irradiation in gamma source at 5 kGy in simultaneous process. The last part was used as obtained. The luminescent polymer matrices were characterized using the techniques of infrared (FTIR) and thermogravimetry (TGA/DTG). Samples of the films were, in presence of fluorine monomers, exposed to ionizing radiation in dose of 5 kGy, for react with monomers in the doped polymer surface. In this case the effects of radiation were evaluated on the luminescent films. (author)

Doping the dots: doped quantum dots for luminescent solar concentrators

NARCIS (Netherlands)

Eilers, J.J.

2015-01-01

In this thesis, synthesis methods for luminescent organically capped colloidal ZnSe QDs of different sizes, ranging from 4.0 to 7.5 nm are reported. These QDs are analyzed using TEM, absorption spectroscopy, photoluminescence measurements and temperature dependent photoluminescence decay

Endoscopic Cerenkov luminescence imaging: in vivo small animal tumor model validation

Science.gov (United States)

Song, Tianming; Bao, Chengpeng; Hu, Zhenhua; Wang, Kun; Liu, Xia; Tian, Jie

2015-03-01

Background: Cerenkov luminescence imaging (CLI) provides a great potential for clinical translation of optical molecular imaging techniques through using clinical approved radiotracers. However, it is difficult to obtain the Cerenkov luminescence signal of deeper biological tissues due to the small magnitude of the signal. To efficiently acquire the weak Cerenkov luminescence, we developed an endoscopic Cerenkov luminescence imaging (ECLI) system to reduce the in vivo imaging depth with minimum invasion, and validated the system on small animal tumor models. Methods: For the ECLI system, the laparoscope was connected to a high sensitive charge-couple device (CCD) camera (DU888+, Andor, UK) by a custom made adapter. We conducted a series of in vitro and in vivo experiments by use of the system. In the in vitro experiment, the endoscopic luminescence images of the 18F-FDG with various activities in EP tubes were acquired using ECLI system, and the sensitivity was compared with conventional CLI system. In the in vivo tumor experiment, 18F-FDG with the activity of 200μCi were intravenously injected into 3 tumor mice. Then the ECLI system was used to acquire the optical images for both non-invasive and invasive conditions. Conclusion: Experimental data showed the ECLI system could detect the 18F-FDG with the activity as low as 1μCi. Furthermore, our preliminary results indicated the possibility of ECLI technique for detecting Cerenkov signals inside the tumor tissue with deeper depth and guiding the surgical operation of tumor excision. We believe that this technique can help to accelerate the clinical translation of CLI.

On luminescence lifetimes in quartz

International Nuclear Information System (INIS)

Chithambo, M.L.; Galloway, R.B.

2000-01-01

In this paper we present results of investigations concerning the time dependence of luminescence emission relative to the time of stimulation in quartz. Measurements of time-resolved spectra were performed on a new versatile pulsed light emitting diode system using 525 nm stimulation, an 11 μs duration pulse, a repetition rate of 11 kHz and a 64 μs dynamic range. Effects on luminescence lifetime resulting from sample treatments such as optical stimulation, irradiation, and preheating, are reported

Fabrication of luminescent porous silicon with stain etches and evidence that luminescence originates in amorphous layers

Science.gov (United States)

Fathauer, R. W.; George, T.; Ksendzov, A.; Lin, T. L.; Pike, W. T.; Vasquez, R. P.; Wu, Z.-C.

1992-01-01

Simple immersion of Si in stain etches of HF:HNO3:H2O or NaNO2 in aqueous HF was used to produce films exhibiting luminescence in the visible similar to that of anodically-etched porous Si. All of the luminescent samples consist of amorphous porous Si in at least the near surface region. No evidence was found for small crystalline regions within these amorphous layers.

Luminescence, virulence and quorum sensing signal production by pathogenic Vibrio campbellii and Vibrio harveyi isolates

OpenAIRE

Defoirdt, T.; Verstraete, W.; Bossier, P.

2008-01-01

Aims: To study the relationship between luminescence, autoinducer production and virulence of pathogenic vibrios.Methods and Results: Luminescence, quorum sensing signal production and virulence towards brine shrimp nauplii of 13 Vibrio campbellii and Vibrio harveyi strains were studied. Although only two of the tested strains were brightly luminescent, all of them were shown to produce the three different types of quorum sensing signals known to be produced by Vibrio harveyi. Cell-free cultu...

Cerenkov Luminescence Tomography for In Vivo Radiopharmaceutical Imaging

Directory of Open Access Journals (Sweden)

Jianghong Zhong

2011-01-01

Full Text Available Cerenkov luminescence imaging (CLI is a cost-effective molecular imaging tool for biomedical applications of radiotracers. The introduction of Cerenkov luminescence tomography (CLT relative to planar CLI can be compared to the development of X-ray CT based on radiography. With CLT, quantitative and localized analysis of a radiopharmaceutical distribution becomes feasible. In this contribution, a feasibility study of in vivo radiopharmaceutical imaging in heterogeneous medium is presented. Coupled with a multimodal in vivo imaging system, this CLT reconstruction method allows precise anatomical registration of the positron probe in heterogeneous tissues and facilitates the more widespread application of radiotracers. Source distribution inside the small animal is obtained from CLT reconstruction. The experimental results demonstrated that CLT can be employed as an available in vivo tomographic imaging of charged particle emitters in a heterogeneous medium.

Simple and rapid measurement of α-rays on smear samples using air luminescence

International Nuclear Information System (INIS)

Takiue, M.

1980-01-01

The α-activity collected on smear samples has been measured indirectly using an air luminescence counting method and a liquid scintillation spectrometer. In this method, air luminescence, attributed to the fluorescence emitted by nitrogen molecules excited by α-rays in air, serves to detect α-rays. Thus, sample preparation and α-ray measurement are simple and rapid, and moreover, no radioactive waste solution is produced. Taking into account a low background and a counting efficiency between 10 and 20%, it is estimated that the detectable limit for α-ray measurement is about 1 x 10 -7 μCi/cm 2 for loose contamination. This method is convenient to use in the routine analysis of α-ray-emitting nuclides on smear paper. (author)

Optical recording in functional polymer nanocomposites by multi-beam interference holography

Science.gov (United States)

Zhuk, Dmitrij; Burunkova, Julia; Kalabin, Viacheslav; Csarnovics, Istvan; Kokenyesi, Sandor

2017-05-01

Our investigations relate to the development of new polymer nanocomposite materials and technologies for fabrication of photonic elements like gratings, integrated elements, photonic crystals. The goal of the present work was the development and application of the multi-beam interference method for one step, direct formation of 1-, 2- or even 3D photonic structures in functional acrylate nanocomposites, which contain SiO2 and Au nanoparticles and which are sensitized to blue and green laser illumination. The presence of gold nanoparticles and possibility to excite plasmonic effects can essentially influence the polymerization processes and the spatial redistribution of nanoparticles in the nanocomposite during the recording. This way surface and volume phase reliefs can be recorded. It is essential, that no additional treatments of the material after the recording are necessary and the elements possess high transparency, are stable after some relaxation time. New functionalities can be provided to the recorded structures if luminescent materials are added to such materials.

Luminescence properties of pure and Eu-doped SrI{sub 2} crystals purified by a “Liquinert” process and grown by vertical Bridgman method

Energy Technology Data Exchange (ETDEWEB)

Kawai, Taketoshi, E-mail: buri@p.s.osakafu-u.ac.jp [Osaka Prefecture University, Gakuen-cho 1-1, Naka-ku, Sakai, Osaka 599-8531 (Japan); Sakuragi, Shiro; Hashimoto, Satoshi [Union Materials Inc. 1640 Oshido, Tone-machi, Ibaraki 300-1602 (Japan)

2016-08-15

We have prepared high quality crystals of pure SrI{sub 2} and Eu-doped SrI{sub 2} by our original “Liquinert” process and investigated their luminescence properties. Under the excitation with the 193 nm light of an ArF excimer laser, which corresponds to the wavelength above the bandgap of SrI{sub 2} bulk crystals, the pure and Eu doped SrI{sub 2} crystals exhibit no luminescence band related to defects or impurities around 560 nm. This fact indicates that the crystals prepared by the “Liquinert” process contain lower defects and/or impurities. When the Eu-doped SrI{sub 2} crystals are excited with the 325 nm light of a He–Cd laser, only the luminescence band due to the 5d→4f transition in the Eu{sup 2+} ions is observed around 425 nm. The 425 nm band observed at a forward configuration exhibits the shift to the longer wavelength side and the decrease of the luminescence intensity with increasing Eu concentration. The Eu concentration dependences of the peak wavelength and luminescence intensity are simulated on the basis of a simple self-absorption model. - Highlights: • Our original “Liquinert” process allows us to prepare high quality crystals of SrI{sub 2}. • No luminescence band related with impurities and/or defects is observed. • The 425 nm luminescence bands due to Eu{sup 2+} ions are affected by a self-absorption. • A simple self-absorption model reproduces the changes of the 425 nm bands.

Luminescence dating: methodological research and application to volcanism in the Laschamp environment; Datation par luminescence: recherches methodologiques et applications au volcanisme dans l'environnement de Laschamp

Energy Technology Data Exchange (ETDEWEB)

Bassinet, C

2007-03-15

The aim of this work was to date lava flows from the Chaine des Puys (Massif Central, France) which were chronologically situated during the period of the Laschamp paleo-magnetic event (30-50 ka). The methods used were thermoluminescence and optically stimulated luminescence applied to quartz grains and quartz pebbles extracted from sediments baked by the lava flows. These minerals often emit luminescence signals exhibiting erratic behaviour. Thus, their radiation doses were tentatively determined by various methods to select those which were most likely to yield reliable results. These intercomparisons highlighted a dispersion of results beyond what could be expected from the uncertainties usually associated with each measurement. In the majority of cases, these observations forced us to propose a relatively wide interval in which the most probable age of the sample is included. (author)

Some methods for blindfolded record linkage

Directory of Open Access Journals (Sweden)

Christen Peter

2004-06-01

Full Text Available Abstract Background The linkage of records which refer to the same entity in separate data collections is a common requirement in public health and biomedical research. Traditionally, record linkage techniques have required that all the identifying data in which links are sought be revealed to at least one party, often a third party. This necessarily invades personal privacy and requires complete trust in the intentions of that party and their ability to maintain security and confidentiality. Dusserre, Quantin, Bouzelat and colleagues have demonstrated that it is possible to use secure one-way hash transformations to carry out follow-up epidemiological studies without any party having to reveal identifying information about any of the subjects – a technique which we refer to as "blindfolded record linkage". A limitation of their method is that only exact comparisons of values are possible, although phonetic encoding of names and other strings can be used to allow for some types of typographical variation and data errors. Methods A method is described which permits the calculation of a general similarity measure, the n-gram score, without having to reveal the data being compared, albeit at some cost in computation and data communication. This method can be combined with public key cryptography and automatic estimation of linkage model parameters to create an overall system for blindfolded record linkage. Results The system described offers good protection against misdeeds or security failures by any one party, but remains vulnerable to collusion between or simultaneous compromise of two or more parties involved in the linkage operation. In order to reduce the likelihood of this, the use of last-minute allocation of tasks to substitutable servers is proposed. Proof-of-concept computer programmes written in the Python programming language are provided to illustrate the similarity comparison protocol. Conclusion Although the protocols described in

Luminescent turn-on detection of Hg(II) via the quenching of an iridium(III) complex by Hg(II)-mediated silver nanoparticles.

Science.gov (United States)

Liu, Jinshui; Vellaisamy, Kasipandi; Yang, Guanjun; Leung, Chung-Hang; Ma, Dik-Lung

2017-06-15

A novel luminescent turn-on detection method for Hg(II) was developed. The method was based on the silver nanoparticle (AgNP)-mediated quenching of Ir(III) complex 1. The addition of Hg(II) ions causes the luminescence of complex 1 to be recovered due to the oxidation of AgNPs by Hg(II) ions to form Ag(I) and Ag/Hg amalgam. The luminescence intensity of 1 increased in accord with an increased Hg(II) concentration ranging from 0 nM to 180 nM, with the detection limit of 5 nM. This approach offers an innovative method for the quantification of Hg(II).

Efficient green luminescence of terbium oxalate crystals: A case study with Judd-Ofelt theory and single crystal structure analysis and the effect of dehydration on luminescence

Science.gov (United States)

Alexander, Dinu; Joy, Monu; Thomas, Kukku; Sisira, S.; Biju, P. R.; Unnikrishnan, N. V.; Sudarsanakumar, C.; Ittyachen, M. A.; Joseph, Cyriac

2018-06-01

Design and synthesis of Lanthanide based metal organic framework is a frontier area of research owing to their structural diversity enabling specific applications. The luminescence properties of rare earths, tuned by the structural features of Ln-MOFs are investigated extensively. Rare earth oxalates which can be synthesized in a facile method, ensuring the structural features of MOFs with excellent photoluminescence characteristics deserves much attention. This work is the first time report on the single crystal structure and Judd-Ofelt (JO) theoretical analysis - their correlation with the intense and sharp green luminescence of Terbium oxalate crystals. The intense green luminescence observed for Terbium oxalate crystals for a wide range of excitation from DUV to visible region despite the luminescence limiting factors are discussed. The absence of concentration quenching and lifting up of forbidden nature of f-f transitions, allowing direct excitation of Terbium ions is analysed with the help of JO theory and single crystal structure analysis. The JO analysis predicted the asymmetry of Terbium sites, allowing the electric dipole transitions and from the JO intensity parameters, promising spectroscopic parameters - emission cross section, branching ratio, gain band width and gain coefficient of the material were calculated. The single crystal structure analysis revealed the asymmetry of Tb sites and structure of Terbium oxalate is formed by the hydrogen bonded stacking of overlapped six Terbium membered rings connected by the oxalate ligands. The molecularly thick layers thus formed on the crystal surface are imaged by the atomic force microscopy. The presence of water channels in the structure and the effect of lattice water molecules on the luminescence intensity are also investigated.

Quantitative analysis of time-resolved infrared stimulated luminescence in feldspars

DEFF Research Database (Denmark)

Pagonis, Vasilis; Ankjærgaard, Christina; Jain, Mayank

2016-01-01

Time-resolved infrared-stimulated luminescence (TR-IRSL) from feldspar samples is of importance in the field of luminescence dating, since it provides information on the luminescence mechanism in these materials. In this paper we present new analytical equations which can be used to analyze TR-IR...

Exciton luminescence in CdxMn1-xTe compounds

International Nuclear Information System (INIS)

Caraman, M.; Gashin, P.; Metelitsa, Snejana; Nicorici, Valentina; Nicorici, A.

2002-01-01

The Cd x Mn 1-x Te (0.5 7 W/cm 2 . The luminescence spectra were observed at 78 K. The results of the study had shown that the presence of relatively narrow luminescence peaks localized in the region of the fundamental absorption edge is characteristic for these spectra and for the majority of the crystals a wide maximum in the long wavelength region is observed. The luminescence maxima with an accuracy of ∼ 5 meV correspond to the resonance energy of the excitons of the state with n=1 determined from the absorption spectra. Hence, these maxima can be considered as exciton luminescence stimulated either by the excitons of the state n=1 or bounded to the exciton ionization centers. From the analysis of the absorption and exciton luminescence spectra one can make a conclusion about the fact that the homogeneity extent of the crystals decreases from CdTe to the compounds with x= 0.8 - 0.7 and slightly increases at the x decrease to 0.5. The exciton luminescence lines in CdTe and Cd 0.99 Mn 0.01 Te crystals is shifting by 7 - 10 meV relatively to the lines of free excitons absorption. This fact is explained by the fact that in these crystals, probably, excitons bounding to the lattice inherited defects with the binding energy of 7 - 10 meV participate in the luminescence. In the long wavelength region a wide peak is observed on which the impurity lines are not displayed. In the luminescence spectra of CdTe with 0.1%. As crystals three maxima at 1.51 eV, 1.46 eV and 1.42 eV are revealed. For pure CdTe the maximum at 1.4 eV is also revealed. These maxima are explained by the luminescence through the recombination levels localized at 0.46 eV. (authors)

Study of the liquid water luminescence induced by charged particles

International Nuclear Information System (INIS)

Rusu, Mircea; Stere, Oana; Haiduc, Maria; Caramete, Laurentiu

2004-01-01

Many observations suggested that liquid water (with impurities) could give a luminescence output when irradiated with charged particles. We investigate theoretical and practical possibility of detecting such luminescence. Preliminary results on this possibility are presented, and a layout of the device proposed for measuring luminescence is given. (authors)

The nature of unusual luminescence in natural calcite, CaCO3

Energy Technology Data Exchange (ETDEWEB)

Gaft, M.; Nagli, L.; Panczer, G.; Waychunas, G.; Porat, N.

2008-11-01

The unusual luminescence of particular varieties of natural pink calcite (CaCO{sub 3}) samples was studied by laser-induced time-resolved luminescence spectroscopy at different temperatures. The luminescence is characterized by intense blue emission under short-wave UV lamp excitation with an extremely long decay time, accompanied by pink-orange luminescence under long wave UV excitation. Our investigation included optical absorption, natural thermostimulated luminescence (NTL) and Laser-Induced Breakdown Spectroscopy (LIBS) studies. Two luminescence centers were detected: a narrow violet band, with {lambda}{sub max} = 412 nm, {Delta} = 45 nm, two decay components of {tau}{sub 1} = 5 ns and {tau}{sub 2} = 7.2 ms, accompanied by very long afterglow, and an orange emission band with {lambda}{sub max} = 595 nm, {Delta} = 90 nm and {tau} = 5 ns. Both luminescence centers are thermally unstable with the blue emission disappearing after heating at 500 C, and the orange emission disappearing after heating at different temperatures starting from 230 C, although sometimes it is stable up to 500 C in different samples. Both centers have spectral-kinetic properties very unusual for mineral luminescence, which in combination with extremely low impurity concentrations, prevent their identification with specific impurity related emission. The most likely explanation of these observations may be the presence of radiation-induced luminescence centers. The long violet afterglow is evidently connected with trapped charge carrier liberation, with their subsequent migration through the valence band and ultimate recombination with a radiation-induced center responsible for the unusual violet luminescence.

Ion irradiation effect of alumina and its luminescence

Energy Technology Data Exchange (ETDEWEB)

Aoki, Yasushi; Yamamoto, Shunya; Naramoto, Hiroshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; My, N T

1997-03-01

The luminescence spectra of single crystalline alpha-alumina and ruby which has 0.02% of Cr{sub 2}O{sub 3} as a impurity, induced by 200 keV He{sup +} and Ar{sup +} irradiation were measured at room temperature as a function of irradiation dose. The analysis of the measured spectra showed the existence of three main luminescence features in the wavelength region of 250 to 350 nm, namely anionic color centers, F-center at 411 nm and F{sup +}-center at 330 nm and a band observed around 315 nm. As alpha-alumina was irradiated with He{sup +}, F-center and F{sup +}-center luminescence grew and decayed, but the behaviors of those were different from each other. It seems that a concentration quenching occurred on the F-center luminescence in the dose range above 1x10{sup 14} He/cm{sup 2}. Furthermore, F-center luminescence was strongly suppressed in ruby, compared with that in alumina. On the other hand, the luminescence band around 315 nm appeared only in the early stage of irradiation and did not show its growth part. The dose dependent behavior was similar to that of Cr{sup 3+} emission at 695 nm (R-line) in ruby in both cases of He{sup +} and Ar{sup +} irradiation. Based on the experimental results mentioned above, the processes of defect formation and excitation in alumina in the early stage of ion irradiation will be discussed. (author)

Flight testing of a luminescent surface pressure sensor

Science.gov (United States)

Mclachlan, B. G.; Bell, J. H.; Espina, J.; Gallery, J.; Gouterman, M.; Demandante, C. G. N.; Bjarke, L.

1992-01-01

NASA ARC has conducted flight tests of a new type of aerodynamic pressure sensor based on a luminescent surface coating. Flights were conducted at the NASA ARC-Dryden Flight Research Facility. The luminescent pressure sensor is based on a surface coating which, when illuminated with ultraviolet light, emits visible light with an intensity dependent on the local air pressure on the surface. This technique makes it possible to obtain pressure data over the entire surface of an aircraft, as opposed to conventional instrumentation, which can only make measurements at pre-selected points. The objective of the flight tests was to evaluate the effectiveness and practicality of a luminescent pressure sensor in the actual flight environment. A luminescent pressure sensor was installed on a fin, the Flight Test Fixture (FTF), that is attached to the underside of an F-104 aircraft. The response of one particular surface coating was evaluated at low supersonic Mach numbers (M = 1.0-1.6) in order to provide an initial estimate of the sensor's capabilities. This memo describes the test approach, the techniques used, and the pressure sensor's behavior under flight conditions. A direct comparison between data provided by the luminescent pressure sensor and that produced by conventional pressure instrumentation shows that the luminescent sensor can provide quantitative data under flight conditions. However, the test results also show that the sensor has a number of limitations which must be addressed if this technique is to prove useful in the flight environment.

Direct determination of graphene quantum dots based on terbium-sensitized luminescence

Science.gov (United States)

Llorent-Martínez, Eulogio J.; Molina-García, Lucía; Durán, Gema M.; Ruiz-Medina, Antonio; Ríos, Ángel

2018-06-01

Graphene quantum dots (GQD) were determined in water samples using terbium-sensitized luminescence (TSL). Terbium ions complex with GQD due to the carboxylic groups that are usually present in these nanomaterials, increasing the luminescence signal of terbium. In Tb(III)-GQD complexes, GQD absorb energy at their characteristic excitation wavelength and transfer it to terbium ion, which emits at its particular emission wavelength. The analytical signal, measured at λexc = 257 nm and λem = 545 nm, increases proportionally to GQD concentration between 50 and 500 μg L-1. Under optimum conditions, the proposed method presents a detection limit of 15 μg L-1 and is selective to GQD in the presence of other nanomaterials of similar size. As GQD are highly water-soluble, they are potential contaminants in environmental or drinking waters water samples, and hence the method was applied to the analysis of different drinking waters which were the target samples for the application of the developed method.

Recent Advances on Luminescent Enhancement-Based Porous Silicon Biosensors.

Science.gov (United States)

Jenie, S N Aisyiyah; Plush, Sally E; Voelcker, Nicolas H

2016-10-01

Luminescence-based detection paradigms have key advantages over other optical platforms such as absorbance, reflectance or interferometric based detection. However, autofluorescence, low quantum yield and lack of photostability of the fluorophore or emitting molecule are still performance-limiting factors. Recent research has shown the need for enhanced luminescence-based detection to overcome these drawbacks while at the same time improving the sensitivity, selectivity and reducing the detection limits of optical sensors and biosensors. Nanostructures have been reported to significantly improve the spectral properties of the emitting molecules. These structures offer unique electrical, optic and magnetic properties which may be used to tailor the surrounding electrical field of the emitter. Here, the main principles behind luminescence and luminescence enhancement-based detections are reviewed, with an emphasis on europium complexes as the emitting molecule. An overview of the optical porous silicon microcavity (pSiMC) as a biosensing platform and recent proof-of-concept examples on enhanced luminescence-based detection using pSiMCs are provided and discussed.

Sedimentary record and luminescence chronology of palaeoflood events along the Gold Gorge of the upper Hanjiang River, middle Yangtze River basin, China

Science.gov (United States)

Guo, Yongqiang; Huang, Chun Chang; Zhou, Yali; Pang, Jiangli; Zha, Xiaochun; Fan, Longjiang; Mao, Peini

2018-05-01

Palaeoflood slackwater deposits (SWDs) along the river banks have important implications for the reconstruction of the past hydro-climatic events. Two palaeoflood SWD beds were identified in the Holocene loess-soil sequences on the cliff river banks along the Gold Gorge of the upper Hanjiang River by field investigation and laboratory analysis. They have recorded two palaeoflood events which were dated by optically stimulated luminescence to 3.2-2.8 ka and 2.1-1.8 ka, respectively. The reliability of the ages obtained for the two events are further confirmed by the presence of archaeological remains and good regional pedostratigraphic correlation. The peak discharges of two palaeoflood events at the studied sites were estimated to be 16,560-17,930 m3/s. A correlation with the palaeoflood events identified in the other reaches shows that great floods occurred frequently during the episodes of 3200-2800 and 2000-1700 a BP along the upper Hanjiang River valley during the last 4000 years. These phases of palaeoflood events in central China are well correlated with the climatic variability identified by δ18O record in the stalagmites from the middle Yangtze River Basin and show apparent global linkages. Palaeoflood studies in a watershed scale also imply that strengthened human activities during the Shang dynasty (BCE 1600-1100) and Han dynasty (BCE206-CE265) may have caused accelerated soil erosion along the upper Hanjiang River valley.

Identifying irradiated flour by photo-stimulated luminescence technique

International Nuclear Information System (INIS)

Ros Anita Ahmad Ramli; Muhammad Samudi Yasir; Zainon Othman; Wan Saffiey Wan Abdullah

2013-01-01

Full-text: The photo-stimulated luminescence technique is recommended by European Committee for standardization for the detection food irradiation (EN 13751:2009). This study shows on luminescence technique to identify gamma irradiated five types of flour (corn flour, tapioca flour, wheat flour, glutinos rice flour and rice flour) at three difference dose levels in the range 0.2 - 1 kGy. The signal level is compare with two thresholds (700 and 5000). The majority of irradiated samples produce a strong signal above the upper threshold (5000 counts/ 60 s). All the control samples gave negative screening result while the signals below the lower threshold (700 counts/ 60s) suggest that the sample has not been irradiated. A few samples show the signal levels between the two thresholds (intermediate signals) suggest that further investigation. Reported procedure was also tested over 60 days, confirming the applicability and feasibility of proposed methods. (author)

New Nanomaterials and Luminescent Optical Sensors for Detection of Hydrogen Peroxide

Directory of Open Access Journals (Sweden)

Natalia A. Burmistrova

2015-10-01

Full Text Available Accurate methods that can continuously detect low concentrations of hydrogen peroxide (H2O2 have a huge application potential in biological, pharmaceutical, clinical and environmental analysis. Luminescent probes and nanomaterials are used for fabrication of sensors for H2O2 that can be applied for these purposes. In contrast to previous reviews focusing on the chemical design of molecular probes for H2O2, this mini-review highlights the latest luminescent nanoparticular materials and new luminescent optical sensors for H2O2 in terms of the nanomaterial composition and luminescent receptor used in the sensors. The nanomaterial section is subdivided into schemes based on gold nanoparticles, polymeric nanoparticles with embedded enzymes, probes showing aggregation-induced emission enhancement, quantum dots, lanthanide-based nanoparticles and carbon based nanomaterials, respectively. Moreover, the sensors are ordered according to the type of luminescent receptor used within the sensor membranes. Among them are lanthanide complexes, metal-ligand complexes, oxidic nanoparticles and organic dyes. Further, the optical sensors are confined to those that are capable to monitor the concentration of H2O2 in a sample over time or are reusable. Optical sensors responding to gaseous H2O2 are not covered. All nanomaterials and sensors are characterized with respect to the analytical reaction towards H2O2, limit of detection (LOD, analytical range, electrolyte, pH and response time/incubation time. Applications to real samples are given. Finally, we assess the suitability of the nanomaterials to be used in membrane-based sensors and discuss future trends and perspectives of these sensors in biomedical research.

Luminescence properties in the visible of Dy:YAG/YAG planar waveguides

Energy Technology Data Exchange (ETDEWEB)

Klimczak, M., E-mail: m.klimczak@elka.pw.edu.p [Institute of Microelectronics and Optoelectronics, Koszykowa 75, 00-662 Warsaw (Poland); Malinowski, M. [Institute of Microelectronics and Optoelectronics, Koszykowa 75, 00-662 Warsaw (Poland); Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Sarnecki, J. [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Piramidowicz, R. [Institute of Microelectronics and Optoelectronics, Koszykowa 75, 00-662 Warsaw (Poland); Telekomunikacja Polska Research and Development Centre, Obrzezna 7, 02-691 Warsaw (Poland)

2009-12-15

In this work, we investigate visible emission properties of dysprosium-doped yttrium aluminum garnet (YAG) waveguides prepared by the liquid phase epitaxy (LPE) method, which allowed obtaining samples of activator concentrations ranging from 0.2 at% up to ca. 18 at%. This unique set of Dy:YAG/YAG waveguides has been carefully examined by means of highly resolved laser spectroscopy to explore the luminescence properties in the visible (yellow-blue) part of spectrum. In particular, the low-temperature absorption spectra have been recorded and analyzed, giving a more detailed information on energy levels' positions in these crystals. The concentration-dependant emission spectra and fluorescence dynamics profiles have been collected under direct excitation, enabling analysis of multi-ion processes responsible for concentration quenching. This, in turn, enabled optimization of activator concentration with respect to yellow emission efficiency. Additionally, the possible IR to visible up-conversion pathways have been discussed, giving a starting point for further investigations.

X-ray luminescent glasses

International Nuclear Information System (INIS)

Takahashi, T.; Yamada, O.

1981-01-01

X-ray luminescent glasses comprising a divalent cation such as an alkaline earth metal or other divalent cations such as pb, cd, or zn, and certain rare earth metaphosphates are suitable as vitreous, x-ray phosphors or x-ray luminescent glass fibers in an x-ray intensifying screen. The glasses have the composition n(Mo X p2o5)((1-y)tb2o3 X yce2o3 X 3p2o5) wherein N is greater than zero but less than or equal to 16, M is an alkaline earth metal or other divalent cation such as pb, cd, or zn, and Y is greater than or equal to zero but less than one

Pixel-based parametric source depth map for Cerenkov luminescence imaging

International Nuclear Information System (INIS)

Altabella, L.; Spinelli, A.E.; Boschi, F.

2016-01-01

Optical tomography represents a challenging problem in optical imaging because of the intrinsically ill-posed inverse problem due to photon diffusion. Cerenkov luminescence tomography (CLT) for optical photons produced in tissues by several radionuclides (i.e.: 32P, 18F, 90Y), has been investigated using both 3D multispectral approach and multiviews methods. Difficult in convergence of 3D algorithms can discourage to use this technique to have information of depth and intensity of source. For these reasons, we developed a faster 2D corrected approach based on multispectral acquisitions, to obtain source depth and its intensity using a pixel-based fitting of source intensity. Monte Carlo simulations and experimental data were used to develop and validate the method to obtain the parametric map of source depth. With this approach we obtain parametric source depth maps with a precision between 3% and 7% for MC simulation and 5–6% for experimental data. Using this method we are able to obtain reliable information about the source depth of Cerenkov luminescence with a simple and flexible procedure

Towards dating Quaternary sediments using the quartz Violet Stimulated Luminescence (VSL) signal

DEFF Research Database (Denmark)

Ankjærgaard, C.; Jain, Mayank; Wallinga, J.

2013-01-01

Quaternary sediments using the violet (402 nm) stimulated luminescence (VSL) signal of quartz.We develop and test a new post-blue VSL single aliquot regenerative dose dating protocol, and demonstrate that the VSL signal originates from a deep trap at about 1.9 eV with a thermal lifetime of 1011 years at 10......Quartz optically stimulated luminescence (OSL) dating is widely used to determine the time of deposition and burial of Late Quaternary sediments. Application of the method is usually limited to the past 150,000 years due to early saturation of the OSL signal. Here we explore the potential to date...

Recent advances of cerium oxide nanoparticles in synthesis, luminescence and biomedical studies：a review

Institute of Scientific and Technical Information of China (English)

何立莹; 苏玉民; 蒋兰宏; 石士考

2015-01-01

Nanostructured cerium oxide (CeO2) commonly known as nanoceria is a rare earth metal oxide, which plays a technologi-cally important role due to its versatile applications as automobile exhaust catalysts, oxide ion conductors in solid oxide fuel cells, electrode materials for gas sensors, ultraviolet absorbents and glass-polishing materials. However, nanoceria has little or weak lumi-nescence, and therefore its uses in high-performance luminescent devices and biomedical areas are limited. In this review, we present the recent advances of nanoceria in the aspects of synthesis, luminescence and biomedical studies. The CeO2 nanoparticles can be synthesized by solution-based methods including co-precipitation, hydrothermal, microemulsion process, sol-gel techniques, combus-tion reaction and so on. Achieving controlled morphologies and enhanced luminescence efficiency of nanoceria particles are quite es-sential for its potential energy- and environment-related applications. Additionally, a new frontier for nanoceria particles in biomedi-cal research has also been opened, which involves low toxicity, retinopathy, biosensors and cancer therapy aspects. Finally, the sum-mary and outlook on the challenges and perspectives of the nanoceria particles are proposed.

K2SO4 and LiKSO4 crystals luminescence

International Nuclear Information System (INIS)

Charapiev, B.; Nurakhmetov, T.N.

2002-01-01

In the paper a nature of X-ray and tunnel luminescence in LiKSO 4 and Li 2 SO 4 ·H 2 O crystals are discussed. It is shown, that X-ray luminescence and Li 2 SO 4 ·H 2 O and LiKSO 4 appeals in the result of electrons recombination with auto-localized holes (SO 4 - ), and tunnel luminescence appeals at electrons transfer from ground state of electron center into hole center capture ground state. Under heating of irradiated crystal de-localized holes at recombination moment with electron capture centers are forming auto-localized excitons, which are disintegrating with photon emitting, and so X-ray luminescence spectrum and thermally induces luminescence peaks are coinciding. Nature of radiation appealing in LiKSO 4 at ultraviolet excitation is discussing

Luminescence properties of some food dye-stuffs

International Nuclear Information System (INIS)

Astanov, S.Kh.; Muminova, Z.A.; Urunov, R.G.

2004-01-01

The luminescence properties of the natural food dye-stuffs and vitamins in temperature range of 300-5.2 K are studied. On the basis of experimental data on quantum yields of the fluorescence, trans-cis-isomerization and luminescence of the molecular oxygen the main ways of the inactivation of electronic excitations in researching compounds have been defined. (author)

Control of spontaneous emission rate in luminescent resonant diamond particles

Science.gov (United States)

Savelev, R.; Zalogina, A.; Kudryashov, S.; Ivanova, A.; Levchenko, A.; Makarov, S.; Zuev, D.; Shadrivov, I.

2018-01-01

We study the properties of luminescent diamond particles of different sizes (up to ~1.5 μm) containing multiple NV-centers. We theoretically predict that the average liftetime in such particles is decreased by several times as compared to optically small subwavelength nanodiamonds. In our experiments, samples were obtained by milling the plasma-enhanced chemical vapor deposited diamond film, and characterized by Raman spectroscopy and dark- field spectroscopy methods. Time-resolved luminescence measurements of the excited state of NV-centers showed that their average lifetime varies from 10 to 17 ns in different samples. By comparing this data to the values of the lifetime of the NV-centers in optically small nanodiamonds, known from literature, we confirm a severalfold decrease of the lifetime in resonant particles.

Effect of retrapping on the persistent luminescence in strontium silicate orange–yellow phosphor

International Nuclear Information System (INIS)

Xu, Xuhui; Yu, Xue; Zhou, Dacheng; Qiu, Jianbei

2013-01-01

The orange–yellow long persistent luminescence in Sr 3 SiO 5 :Eu 2+ , Er 3+ with the chromaticity coordination of (0.48, 0.49) can persist for over 20 h above the recognizable intensity level (≥0.32 mcd/m 2 ) because of retrapping carriers by the deep traps. The incorporation of Er 3+ into Sr 3 SiO 5 :Eu 2+ generates a large number of shallow traps responsible for the fast decay component as well as deep traps responsible for the decay tail of the LPL. It demonstrates that the retrapping of the carrier released from a trap plays an important role in the persistent luminescence process. - Graphical abstract: LPL decay curves of Sr 3−x−y SiO 5 :xEu 2+ , yEr 3+ (x=0.0025, y=0, 0.0025). Inset: Orange–yellow emission images recorded using a classic Reflex digital camera with exposure times varying with the persistent luminescence times. Display Omitted - Highlights: • The persistence time of Sr 3 SiO 5 :Eu 2+ , Er 3+ lasts over 20 h above the recognizable intensity level. • The incorporation of Er 3+ into Sr 3 SiO 5 :Eu 2+ generates a large number of shallow traps. • The experimental results provide an evidence for the retrapping process in LPL processes

Studies of nanostructures using time-resolved x-ray excited optical luminescence*

International Nuclear Information System (INIS)

Rosenberg, R.A.; Shenoy, G.K.; Smita, S.; Burda, C.; Sham, T.K.

2004-01-01

Full text:The scientific community is currently investing a great deal of effort into understanding the physics and chemistry of nanoscale structures. Synchrotron radiation techniques are being used to study the physical, electronic, and magnetic structure of nanosystems, albeit at a relatively large size (greater than 30 nm). A major challenge facing researchers is finding methods that can probe structures of the smallest scale (less than 10 nm). Optical luminescence has been shown to be directly sensitive to structures in this size range due to quantum confinement phenomena. X-ray-excited optical luminescence (XEOL) provides the capability to chemically map the sites responsible for producing low-energy (1-6 eV) fluorescence. By taking advantage of the time structure of the x-ray pulses at the Advanced Photon Source (70 ps wide, 153 ns separation), it also possible to determine the dynamic behavior of the states involved in the luminescence. In this paper we will present results of time-resolved XEOL experiments on various nanostructures including porous silicon, silicon nanowires, and CdSe nanodots

The remote methods for radwaste and SNF control

International Nuclear Information System (INIS)

Ivanov, O; Stepanov, V; Danilovich, A; Potapov, V

2017-01-01

With the examples of developments carried out in the Kurchatov Institute and by the world leaders in the field the presentation considers the devices and methods to obtain remotely information on the distribution of radioactivity in radwaste and SNF. It describes the different types of light portable gamma cameras. The application of scanning spectrometric systems is considers also. The methods of recording UV radiation for detection of alpha contamination with the luminescence of air are presented. We discuss the scope and tasks that can be solved using remote and non-destructive methods. (paper)

Luminescence dating: methodological research and application to volcanism in the Laschamp environment

International Nuclear Information System (INIS)

Bassinet, C.

2007-03-01

The aim of this work was to date lava flows from the Chaine des Puys (Massif Central, France) which were chronologically situated during the period of the Laschamp paleo-magnetic event (30-50 ka). The methods used were thermoluminescence and optically stimulated luminescence applied to quartz grains and quartz pebbles extracted from sediments baked by the lava flows. These minerals often emit luminescence signals exhibiting erratic behaviour. Thus, their radiation doses were tentatively determined by various methods to select those which were most likely to yield reliable results. These intercomparisons highlighted a dispersion of results beyond what could be expected from the uncertainties usually associated with each measurement. In the majority of cases, these observations forced us to propose a relatively wide interval in which the most probable age of the sample is included. (author)

Use of a highly sensitive two-dimensional luminescence imaging system to monitor endogenous bioluminescence in plant leaves

Directory of Open Access Journals (Sweden)

Flor-Henry Michel

2004-11-01

Full Text Available Abstract Background All living organisms emit spontaneous low-level bioluminescence, which can be increased in response to stress. Methods for imaging this ultra-weak luminescence have previously been limited by the sensitivity of the detection systems used. Results We developed a novel configuration of a cooled charge-coupled device (CCD for 2-dimensional imaging of light emission from biological material. In this study, we imaged photon emission from plant leaves. The equipment allowed short integration times for image acquisition, providing high resolution spatial and temporal information on bioluminescence. We were able to carry out time course imaging of both delayed chlorophyll fluorescence from whole leaves, and of low level wound-induced luminescence that we showed to be localised to sites of tissue damage. We found that wound-induced luminescence was chlorophyll-dependent and was enhanced at higher temperatures. Conclusions The data gathered on plant bioluminescence illustrate that the equipment described here represents an improvement in 2-dimensional luminescence imaging technology. Using this system, we identify chlorophyll as the origin of wound-induced luminescence from leaves.

Two-step excitation structure changes of luminescence centers and strong tunable blue emission on surface of silica nanospheres

Energy Technology Data Exchange (ETDEWEB)

Yang, Lei, E-mail: nanoyang@qq.com; Jiang, Zhongcheng; Dong, Jiazhang; Zhang, Liuqian [Hunan University, College of Materials Science and Engineering (China); Pan, Anlian, E-mail: anlian.pan@gmail.com; Zhuang, Xiujuan [Hunan University, Key Laboratory for Micro-Nano Physics and Technology of Hunan Province (China)

2015-10-15

We report a scheme for investigating two-step stimulated structure change of luminescence centers. Amorphous silica nanospheres with uniform diameter of 9–15 nm have been synthesized by Stöber method. Strong hydroxyl-related infrared-absorption band is observed in infrared spectrum. The surface hydroxyl groups exert great influence on the luminescent behavior of silica. They provide stable and intermediate energy states to accommodate excitation electrons. The existence of these surface states reduces the energy barrier of photochemical reactions, creating conditions for two-step excitation process. By carefully examining excitation and emission process, the nearest excitation band is absent in both optical absorption spectrum and excitation spectrum. This later generated state confirms the generation of new luminescence centers as well as the existence of photochemical reactions. Stimulated by different energies, two-step excitation process impels different photochemical reactions, prompting generation of different lattice defects on surface area of silica. Thereby, tunable luminescence is achieved. After thermal treatment, strong gap excitation band appears with the disappearance of strong surface excitation band. Strong blue luminescence also disappears. The research is significance to precise introducing structural defects and controlling position of luminescence peaks.

Luminescent materials and their applications

CERN Document Server

Virk, Hardev Singh

2015-01-01

It is pertinent to note that Luminescence phenomenon has once again occupied a central stage with the announcement of Nobel Prize in October 2014 to three Japanese scientists. The discovery of Galium Nitride proved to be a revolutionary step forward in creation of Blue LEDs. With the advent of LED lamps we now have more long-lasting and more efficient alternatives to older light sources. The Volume under reference consists of 9 Chapters, written by experts in the area of Luminescent Materials. First 5 Chapters are contributed as Review Papers and the last 4 are based on Research Papers.Chapter

Cerium luminescence in nd0 perovskites

International Nuclear Information System (INIS)

Setlur, A.A.; Happek, U.

2010-01-01

The luminescence of Ce 3+ in perovskite (ABO 3 ) hosts with nd 0 B-site cations, specifically Ca(Hf,Zr)O 3 and (La,Gd)ScO 3 , is investigated in this report. The energy position of the Ce 3+ excitation and emission bands in these perovskites is compared to those of typical Al 3+ perovskites; we find a Ce 3+ 5d 1 centroid shift and Stokes shift that are larger versus the corresponding values for the Al 3+ perovskites. It is also shown that Ce 3+ luminescence quenching is due to Ce 3+ photoionization. The comparison between these perovskites shows reasonable correlations between Ce 3+ luminescence quenching, the energy position of the Ce 3+ 5d 1 excited state with respect to the host conduction band, and the host composition. - Graphical abstract: Ce 3+ decay times versus temperature for perovskites with nd 0 B-site cations.

Paper-based biodetection using luminescent nanoparticles.

Science.gov (United States)

Ju, Qiang; Noor, M Omair; Krull, Ulrich J

2016-05-10

Point-of-care and in-field technologies for rapid, sensitive and selective detection of molecular biomarkers have attracted much interest. Rugged bioassay technology capable of fast detection of markers for pathogens and genetic diseases would in particular impact the quality of health care in the developing world, but would also make possible more extensive screening in developed countries to tackle problems such as those associated with water and food quality, and tracking of infectious organisms in hospitals and clinics. Literature trends indicate an increasing interest in the use of nanomaterials, and in particular luminescent nanoparticles, for assay development. These materials may offer attributes for development of assays and sensors that could achieve improvements in analytical figures of merit, and provide practical advantages in sensitivity and stability. There is opportunity for cost-efficiency and technical simplicity by implementation of luminescent nanomaterials as the basis for transduction technology, when combined with the use of paper substrates, and the ubiquitous availability of cell phone cameras and associated infrastructure for optical detection and transmission of results. Luminescent nanoparticles have been described for a broad range of bioanalytical targets including small molecules, oligonucleotides, peptides, proteins, saccharides and whole cells (e.g., cancer diagnostics). The luminescent nanomaterials that are described herein for paper-based bioassays include metal nanoparticles, quantum dots and lanthanide-doped nanocrystals. These nanomaterials often have broad and strong absorption and narrow emission bands that improve opportunity for multiplexed analysis, and can be designed to provide emission at wavelengths that are efficiently processed by conventional digital cameras. Luminescent nanoparticles can be embedded in paper substrates that are designed to direct fluid flow, and the resulting combination of technologies can offer

Luminescence properties of tetravalent uranium in aqueous solution

International Nuclear Information System (INIS)

Kirishima, A.; Kimura, T.; Nagaishi, R.; Tochiyama, O.

2004-01-01

The luminescence spectra of U 4+ in aqueous solutions were observed in the UV-VIS region at ambient and liquid nitrogen temperatures. The excitation spectrum indicates that the luminescence is arising from the deexcitation of a 5f electron at the 1 S 0 level and no other emissions of U 4+ in aqueous solutions were detected for other f-f transitions. All the luminescence peaks were assigned to the transitions from 1 S 0 to lower 5f levels. To estimate the luminescence lifetime, luminescence decay curves were measured using time-resolved laser-induced fluorescence spectroscopy. At room temperature, the decay curve indicated that the lifetime was shorter than 20 ns. On the other hand, the frozen sample of U 4+ in aqueous solution at liquid nitrogen temperature showed the same emission spectrum as at room temperature and its lifetime was 149 ns in H 2 O system and 198 ns in D 2 O system. The longer lifetime at liquid nitrogen temperature made it possible to measure the spectrum of U 4+ at the concentration as low as 10 -6 M. The difference in the anion species (ClO 4 - , Cl - , SO 4 2- ) affected the structure of the emission spectrum to some extent. (orig.)

Novel lanthanide doped micro- and mesoporous solids. Characterization of ion-host-interactions, species distribution and luminescence properties using time-resolved luminescence spectroscopy; Neuartige Lanthanoid-dotierte mikro- und mesoporoese Feststoffe. Charakterisierung von Ion-Wirt-Wechselwirkungen, Speziesverteilung und Lumineszenzeigenschaften mittels zeitaufgeloester Lumineszenzspektroskopie

Energy Technology Data Exchange (ETDEWEB)

Gessner, Andre

2010-12-15

In this work lanthanide-doped microporous zeolites, microporous-mesoporous hybrid materials and mesoporous silicates were investigated regarding their luminescence properties and the ion-host-interactions using time-resolved luminescence spectroscopy. Thereby, time-resolved emission spectra (TRES) provide information in the wavelength and time domain. For the analysis of the TRES a broad set of analytic methods was applied and thus a corresponding ''toolbox'' developed. Fitting of the luminescence decays was performed with a discrete number of exponentials and supported by luminescence decay times distributions. Time-resolved area normalized emission spectra (TRANES), an advancement of TRES, could be used for the determination of the number of emissive lanthanide species in porous materials for the first time. Calculation of the decay-associated spectra (DAS) allowed the correlation of spectral information with luminescence decay times and thus delivered the luminescence spectra of the different europium species. For europium(III) we could use in addition the time-dependent asymmetry ratio and spectral evolution of the {sup 5}D{sub 0}-{sup 7}F{sub 0}-transition with time to obtain further information about the distribution of the lanthanide ions in the host material. Luminescence decay times and spectra allowed conclusions on the number of OH-oscillators in and the symmetry of the first coordination sphere. For the microporous and microporous-mesoporous materials were found different lanthanide species, which were characterized by the above mentioned methods. These lanthanide species can be found on different positions in the host material. One position is located deep in the pore system. Here, lanthanide ions are hardly accessible for water and mainly coordinated by framework oxygens. This results in long luminescence decay times and distorted coordination spheres. The second position can be found near or on the outer surface or in the

Nanostructured Ag-zeolite Composites as Luminescence-based Humidity Sensors

Science.gov (United States)

Dieu, Bjorn; Roeffaers, Maarten B.J.; Hofkens, Johan

2016-01-01

Small silver clusters confined inside zeolite matrices have recently emerged as a novel type of highly luminescent materials. Their emission has high external quantum efficiencies (EQE) and spans the whole visible spectrum. It has been recently reported that the UV excited luminescence of partially Li-exchanged sodium Linde type A zeolites [LTA(Na)] containing luminescent silver clusters can be controlled by adjusting the water content of the zeolite. These samples showed a dynamic change in their emission color from blue to green and yellow upon an increase of the hydration level of the zeolite, showing the great potential that these materials can have as luminescence-based humidity sensors at the macro and micro scale. Here, we describe the detailed procedure to fabricate a humidity sensor prototype using silver-exchanged zeolite composites. The sensor is produced by suspending the luminescent Ag-zeolites in an aqueous solution of polyethylenimine (PEI) to subsequently deposit a film of the material onto a quartz plate. The coated plate is subjected to several hydration/dehydration cycles to show the functionality of the sensing film. PMID:27911397

[Synthesis of reserve polyhydroxyalkanoates by luminescent bacteria].

Science.gov (United States)

Boiandin, A N; Kalacheva, G S; Rodicheva, E K; Volova, T G

2008-01-01

The ability of marine luminescent bacteria to synthesize polyesters of hydroxycarboxylic acids (polyhydroxyalkanoates, PHA) as reserve macromolecules was studied. Twenty strains from the collection of the luminescent bacteria CCIBSO (WDSM839) of the Institute of Biophysics, Siberian Branch, Russian Academy of Sciences, assigned to different taxa (Photobacterium leiognathi, Ph. phosphoreum, Vibrio harveyi, and V. fischeri) were analyzed. The most productive strains were identified, and the conditions ensuring high polymer yields in batch culture (40-70% of the cell dry mass weight) were determined. The capacity of synthesizing two- and three-component polymers containing hydroxybutyric acid as the main monomer and hydroxyvaleric and hydroxyhexanoic acids was revealed in Ph. leiognathi and V. harveyi strains. The results allow luminescent microorganisms to be regarded as new producers of multicomponent polyhydroxyalkanoates.

Ion beam induced luminescence of germano-silicate optical fiber preform

Energy Technology Data Exchange (ETDEWEB)

Jung, Hyunkyu; Kim, Jongyeol; Lee, Namho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Youngwoong; Han, Wontaek [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Markovic, Nikola; Jaksic, Milko [Ruder Boskovic Institute, Zagred (Croatia)

2014-05-15

When an optical fiber is exposed to radiation, the attenuation (RIA, Radiation Induced Attenuation) in the optical fiber (OF) is increased because of the color centers which deteriorate the transmission property and generate the absorption loss. In order to understand the radiation induced defect, Ion Beam induced luminescence (IBIL) was introduced to investigate it. IBIL technique is to analyze IR/VIS/UV luminescence related to ion beam interaction with outer shell electrons involved in chemical bonds and structure defects of target atoms. So IBIL is sensitive to its chemical composition and has been used in analysis of material characterization, geological samples and cultural heritage objects. In silica material, four O atoms are surrounding one Si atom in tetrahedral coordination. In this study, the influence of Copper (Cu) and Cerium (Ce) dopants to germano silica core optical fibers were investigated under proton irradiation at RBI using Ion Beam induced luminescence (IBIL) method. To understand the radiation induced defect of optical fibers, IBIL were tested to a germano-silica core fiber under 2 MeV proton irradiation. Although a Cu or Ce dopant was not detected by IBIL technique, the relation between the amount of radiation and luminescence can be established. This experiment showed a potential technique of studying the effects and behavior of additive elements for silica core fiber. To increase the radiation resistance of optical fibers, further investigations are needed, i. e. the proper additives and its contents and an interaction mechanism between Ge-related defects and additives.

Ion beam induced luminescence of germano-silicate optical fiber preform

International Nuclear Information System (INIS)

Jung, Hyunkyu; Kim, Jongyeol; Lee, Namho; Kim, Youngwoong; Han, Wontaek; Markovic, Nikola; Jaksic, Milko

2014-01-01

When an optical fiber is exposed to radiation, the attenuation (RIA, Radiation Induced Attenuation) in the optical fiber (OF) is increased because of the color centers which deteriorate the transmission property and generate the absorption loss. In order to understand the radiation induced defect, Ion Beam induced luminescence (IBIL) was introduced to investigate it. IBIL technique is to analyze IR/VIS/UV luminescence related to ion beam interaction with outer shell electrons involved in chemical bonds and structure defects of target atoms. So IBIL is sensitive to its chemical composition and has been used in analysis of material characterization, geological samples and cultural heritage objects. In silica material, four O atoms are surrounding one Si atom in tetrahedral coordination. In this study, the influence of Copper (Cu) and Cerium (Ce) dopants to germano silica core optical fibers were investigated under proton irradiation at RBI using Ion Beam induced luminescence (IBIL) method. To understand the radiation induced defect of optical fibers, IBIL were tested to a germano-silica core fiber under 2 MeV proton irradiation. Although a Cu or Ce dopant was not detected by IBIL technique, the relation between the amount of radiation and luminescence can be established. This experiment showed a potential technique of studying the effects and behavior of additive elements for silica core fiber. To increase the radiation resistance of optical fibers, further investigations are needed, i. e. the proper additives and its contents and an interaction mechanism between Ge-related defects and additives

Influence of Nanosized Silicon Oxide on the Luminescent Properties of ZnO Nanoparticles

Directory of Open Access Journals (Sweden)

Vitaliy Shvalagin

2016-01-01

Full Text Available For practical use of nanosized zinc oxide as the phosphor its luminescence quantum yields should be maximized. The aim of this work was to enhance luminescent properties of ZnO nanoparticles and obtain high-luminescent ZnO/SiO2 composites using simpler approaches to colloidal synthesis. The luminescence intensity of zinc oxide nanoparticles was increased about 3 times by addition of silica nanocrystals to the source solutions during the synthesis of ZnO nanoparticles. Then the quantum yield of luminescence of the obtained ZnO/SiO2 composites is more than 30%. Such an impact of silica is suggested to be caused by the distribution of ZnO nanocrystals on the surface of silica, which reduces the probability of separation of photogenerated charges between the zinc oxide nanoparticles of different sizes, and as a consequence, there is a significant increase of the luminescence intensity of ZnO nanoparticles. This way of increasing nano-ZnO luminescence intensity facilitates its use in a variety of devices, including optical ultraviolet and visible screens, luminescent markers, antibacterial coatings, luminescent solar concentrators, luminescent inks for security printing, and food packaging with abilities of informing consumers about the quality and safety of the packaged product.

The spatially resolved characterisation of Egyptian blue, Han blue and Han purple by photo-induced luminescence digital imaging.

Science.gov (United States)

Verri, G

2009-06-01

The photo-induced luminescence properties of Egyptian blue, Han blue and Han purple were investigated by means of near-infrared digital imaging. These pigments emit infrared radiation when excited in the visible range. The emission can be recorded by means of a modified commercial digital camera equipped with suitable glass filters. A variety of visible light sources were investigated to test their ability to excite luminescence in the pigments. Light-emitting diodes, which do not emit stray infrared radiation, proved an excellent source for the excitation of luminescence in all three compounds. In general, the use of visible radiation emitters with low emission in the infrared range allowed the presence of the pigments to be determined and their distribution to be spatially resolved. This qualitative imaging technique can be easily applied in situ for a rapid characterisation of materials. The results were compared to those for Egyptian green and for historical and modern blue pigments. Examples of the application of the technique on polychrome works of art are presented.

On the correlation between annealing and variabilities in pulsed-luminescence from quartz

International Nuclear Information System (INIS)

Chithambo, M.L.

2006-01-01

Properties of luminescence lifetimes in quartz related to annealing between 500 and 900 deg. C have been investigated. The luminescence was pulse-stimulated at 470nm from sets of granular quartz annealed at 500, 600, 700, 800, and 900 deg. C. The lifetimes decrease with annealing temperature from about 42 to 33μs when the annealing temperature is increased from 500 to 900 deg. C. Luminescence lifetimes are most sensitive to duration of annealing at 600 deg. C, decreasing from 40.2+/-0.7μs by as much as 7μs when the duration of annealing is changed from 10 to 60min. However, at 800-900 deg. C lifetimes are essentially independent of annealing temperature at about 33μs. Increasing the exciting beta dose causes an increase in the lifetimes of the stimulated luminescence in the sample annealed at 800 deg. C but not in those annealed at either 500 or 600 deg. C. The temperature-resolved distribution of luminescence lifetimes is affected by thermal quenching of luminescence. These features may be accounted for with reference to two principal luminescence centres involved in the luminescence emission process

Luminescence characteristics of dental ceramics for retrospective dosimetry: a preliminary study

International Nuclear Information System (INIS)

Bailiff, I.K.; Correcher, V.; Delgado, A.; Goksu, Y.; Huebner, S.

2002-01-01

Ceramic materials that are widely employed in dental prosthetics and repairs exhibit luminescent properties. Because of their use in the body, these materials are potentially of interest in situations where retrospective dosimetry for individuals is required but where monitoring was not planned. The luminescent properties of dental ceramics obtained in Germany, Spain and the UK were examined. Linear dose-response characteristics were obtained in the range <100 mGy to 10 Gy using thermoluminescence (TL), optically stimulated luminescence and infrared-stimulated luminescence measurement techniques. Measurements of time-resolved luminescence were also performed to examine the nature of the luminescence recombination under visible (470 nm) and IR (855 nm) stimulation. The results obtained by TL and optically stimulated techniques suggest that there may be deeper traps than previously observed in certain types of dental ceramic. Such traps may be less susceptible to optical and athermal fading than was reported in earlier studies. (author)

Quantitative analysis of time-resolved infrared stimulated luminescence in feldspars

Energy Technology Data Exchange (ETDEWEB)

Pagonis, Vasilis, E-mail: vpagonis@mcdaniel.edu [McDaniel College, Physics Department, Westminster, MD 21157 (United States); Ankjærgaard, Christina [Soil Geography and Landscape Group & Netherlands Centre for Luminescence dating, Wageningen University, PO Box 47, 6700 AA Wageningen (Netherlands); Jain, Mayank [Center for Nuclear Technologies, Technical University of Denmark, DTU Risø Campus, Roskilde (Denmark); Chithambo, Makaiko L. [Department of Physics and Electronics, Rhodes University, PO BOX 94, Grahamstown 6140 (South Africa)

2016-09-15

Time-resolved infrared-stimulated luminescence (TR-IRSL) from feldspar samples is of importance in the field of luminescence dating, since it provides information on the luminescence mechanism in these materials. In this paper we present new analytical equations which can be used to analyze TR-IRSL signals, both during and after short infrared stimulation pulses. The equations are developed using a recently proposed kinetic model, which describes localized electronic recombination via tunneling between trapped electrons and recombination centers in luminescent materials. Recombination is assumed to take place from the excited state of the trapped electron to the nearest-neighbor center within a random distribution of luminescence recombination centers. Different possibilities are examined within the model, depending on the relative importance of electron de-excitation and recombination. The equations are applied to experimental TR-IRSL data of natural feldspars, and good agreement is found between experimental and modeling results.

Luminescence dating at Rose cottage cave: a progress report

CSIR Research Space (South Africa)

Woodborne, S

1997-10-01

Full Text Available Deal with infrared-stimulated luminescence and thermoluminescence dates from Rose Cottage Cave in South Africa. Discrepancy between luminescence and radiocarbon dates; Concentration of radioactive elements in sediments before and after leaching...

Defect-Induced Luminescence of a Self-Activated Borophosphate Phosphor

Science.gov (United States)

Han, Bing; Liu, Beibei; Dai, Yazhou; Zhang, Jie

2018-05-01

A self-activated borophosphate phosphor Ba3BPO7 was prepared via typical solid-state reaction in thermal-carbon reduction atmosphere. The structural and luminescence properties were investigated using x-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and photoluminescence spectroscopy. Upon excitation with ultraviolet (UV) light, the as-prepared phosphor shows bright greenish-yellow emission with a microsecond-level fluorescence lifetime, which could result from the oxygen vacancies produced in the process of solid-state synthesis. The possible luminescence mechanism is proposed. Through the introduction of defects in the host, this work realizes visible luminescence in a pure borophosphate compound that does not contain any rare earth or transition metal activators, so it is helpful to develop defect-related luminescent materials in view of energy conservation and environmental protection for sustainable development.

Luminescent properties of terbium complex with phenylanthranilic acid

International Nuclear Information System (INIS)

Alakaeva, L.A.; Kalazhokova, I.A.; Naurzhanova, F.Kh.

1990-01-01

Existence of terbium luminescence reaction in complex with phenanthranilic acid (FAA) is ascertained. The optimal conditions of terbium complexing with FAA are found. The ratio of components in the complex is 1:1. The influence of foreign rare earth in terbium luminescence intensity in complex with FAA is studied

Doped luminescent materials and particle discrimination using same

Science.gov (United States)

Doty, F. Patrick; Allendorf, Mark D; Feng, Patrick L

2014-10-07

Doped luminescent materials are provided for converting excited triplet states to radiative hybrid states. The doped materials may be used to conduct pulse shape discrimination (PSD) using luminescence generated by harvested excited triplet states. The doped materials may also be used to detect particles using spectral shape discrimination (SSD).

Smart responsive phosphorescent materials for data recording and security protection.

Science.gov (United States)

Sun, Huibin; Liu, Shujuan; Lin, Wenpeng; Zhang, Kenneth Yin; Lv, Wen; Huang, Xiao; Huo, Fengwei; Yang, Huiran; Jenkins, Gareth; Zhao, Qiang; Huang, Wei

2014-04-07

Smart luminescent materials that are responsive to external stimuli have received considerable interest. Here we report ionic iridium (III) complexes simultaneously exhibiting mechanochromic, vapochromic and electrochromic phosphorescence. These complexes share the same phosphorescent iridium (III) cation with a N-H moiety in the N^N ligand and contain different anions, including hexafluorophosphate, tetrafluoroborate, iodide, bromide and chloride. The anionic counterions cause a variation in the emission colours of the complexes from yellow to green by forming hydrogen bonds with the N-H proton. The electronic effect of the N-H moiety is sensitive towards mechanical grinding, solvent vapour and electric field, resulting in mechanochromic, vapochromic and electrochromic phosphorescence. On the basis of these findings, we construct a data-recording device and demonstrate data encryption and decryption via fluorescence lifetime imaging and time-gated luminescence imaging techniques. Our results suggest that rationally designed phosphorescent complexes may be promising candidates for advanced data recording and security protection.

Polarization memory of white luminescence of Ag nanoclusters dispersed in glass host.

Science.gov (United States)

Kuznetsov, A S; Tikhomirov, V K; Moshchalkov, V V

2012-09-10

A mechanism for white luminescence of Ag nanoclusters dispersed in oxyfluoride glass host has been revealed by studying a temperature dependence of its polarization memory. The spectral dependence of the polarization memory indicates the presence of a variety of Ag nanoclusters, particularly emitting in the blue, green and red. Temperature activated intercluster energy transfer has been found responsible for white luminescence. The means for increasing luminescence quantum yield have been suggested. This efficient white luminescence may be used in highly demanded devices, such as luminescent lamps, displays, color phosphors for LEDs, photovoltaic devices based on down shifting of solar spectrum.

Application of time-correlated single photon counting and stroboscopic detection methods with an evanescent-wave fibre-optic sensor for fluorescence-lifetime-based pH measurements

International Nuclear Information System (INIS)

Henning, Paul E; Geissinger, Peter

2012-01-01

Quasi-distributed optical fibre sensor arrays containing luminescent sensor molecules can be read out spatially resolved utilizing optical time-of-flight detection (OTOFD) methods, which employ pulsed laser interrogation of the luminosensors and time-resolved detection of the sensor signals. In many cases, sensing is based on a change in sensor luminescence intensity; however, sensing based on luminescence lifetime changes is preferable because it reduces the need for field calibration. Because in OTOFD detection is time-resolved, luminescence-lifetime information is already available through the signal pulses, although in practise applications were restricted to sensors with long luminescence lifetimes (hundreds of ns). To implement lifetime-based sensing in crossed-optical-fibre-sensor arrays for sensor molecules with lifetimes less than 10 ns, two time-domain methods, time-correlated single photon counting and stroboscopic detection, were used to record the pH-dependent emission of a fluorescein derivative covalently attached to a highly-porous polymer. A two-term nonexponential decay function yielded both a good fit for experimental lifetime data during reconvolution and a pH response that matches Henderson–Hasselbalch behaviour, yielding a sensor accuracy of 0.02 pH units. Moreover, strong agreement was obtained for the two lifetime determination methods and with intensity-based measurements taken previously. (paper)

Synthesis of high luminescent carbon nanoparticles

Science.gov (United States)

Gvozdyuk, Alina A.; Petrova, Polina S.; Goryacheva, Irina Y.; Sukhorukov, Gleb B.

2017-03-01

In this article we report an effective and simple method for synthesis of high luminescent carbon nanodots (CDs). In our work as a carbon source sodium dextran sulfate (DS) was used because it is harmless, its analogs are used in medicine as antithrombotic compounds and blood substitutes after hemorrhage. was used as a substrate We investigated the influence of temperature parameters of hydrothermal synthesis on the photoluminescence (PL) intensity and position of emission maxima. We discovered that the PL intensity can be tuned by changing of synthesis temperature and CD concentration.

X-ray photoemission spectroscopy investigation of CaTiO3:Eu for luminescence property: effect of Eu3+ ion

International Nuclear Information System (INIS)

Wang, Kaichen; Zhao, Baijun; Gao, Lu

2016-01-01

Graphical abstract: The influence on the photoluminescent performance due to the electronic structure change in Eu-doped CaTiO 3 of the specific core-level and valence band spectrum via X-ray photoemission spectroscopy were characterized. - Highlights: • Single phase CaTiO 3 and CaTiO 3 : Eu crystals were prepared under mild hydrothermal method. • Crystal structure, doping level and the relations to their luminescent property were discussed. • Charge compensation mechanism was discussed via valance band spectrum by XPS. - Abstract: Charge compensation of on-site Eu 4f–5d transition that determines the luminescent performance was confirmed with valance band spectrum. Influence of photoelectrons from CaTiO 3 : Eu to the corresponding luminescent performance was discussed based on the crystal structure, doping level and the relations to their luminescent property. This paper is important to further optimize the luminescent performance for improving the efficiency and reducing the cost in light emitting diode industry.

Preparation and determination of the luminescent characteristics of ZrO2 in powder

International Nuclear Information System (INIS)

Rivera M, T.; Olvera T, L.; Azorin N, J.; Soto E, A.M.; Velazquez O, C.; Campero C, A.

2004-01-01

In this work the luminescent characteristics of the ZrO 2 are presented using the method of Thermally Stimulated Luminescence (TSL), also called thermoluminescence (Tl). The powders of ZrO 2 were obtained by two preparation methods: for precipitation and for evaporation of Sol-gel. The luminescent characteristics of the ZrO 2 are determined using a lamp of radiation of UV light and a radiation source of beta particles of 90 Sr/ 90 Y. Using the method of thermal stimulation the curve representative thermoluminescent of the previously irradiated material was obtained. The curve Tl of the ZrO 2 irradiated with UV light presents a maximum in 180 C. Likewise, the spectrum of the curve Tl of the ZrO 2 irradiated with particles beta presents a maximum centered in 181 C. While using gamma radiation like excitement source one has a spectrum with a peak centered in 184 C. When subjecting the materials obtained by sol-gel to a process of calcination at 1000 C for 24 hours a curved Tl it presents with two maxim in 185 and in 290 C respectively. The intensity of the response induced in the material it is a decisive factor to continue studying the dosimetric characteristics of the ZrO 2 what allows to consider it as a potential material to use it in the beta particle dosimetry and of the UV light using the thermoluminescence method (Tl). (Author)

Principal and secondary luminescence lifetime components in annealed natural quartz

International Nuclear Information System (INIS)

Chithambo, M.L.; Ogundare, F.O.; Feathers, J.

2008-01-01

Time-resolved luminescence spectra from quartz can be separated into components with distinct principal and secondary lifetimes depending on certain combinations of annealing and measurement temperature. The influence of annealing on properties of the lifetimes related to irradiation dose and temperature of measurement has been investigated in sedimentary quartz annealed at various temperatures up to 900 deg. C. Time-resolved luminescence for use in the analysis was pulse stimulated from samples at 470 nm between 20 and 200 deg. C. Luminescence lifetimes decrease with measurement temperature due to increasing thermal effect on the associated luminescence with an activation energy of thermal quenching equal to 0.68±0.01eV for the secondary lifetime but only qualitatively so for the principal lifetime component. Concerning the influence of annealing temperature, luminescence lifetimes measured at 20 deg. C are constant at about 33μs for annealing temperatures up to 600 0 C but decrease to about 29μs when the annealing temperature is increased to 900 deg. C. In addition, it was found that lifetime components in samples annealed at 800 deg. C are independent of radiation dose in the range 85-1340 Gy investigated. The dependence of lifetimes on both the annealing temperature and magnitude of radiation dose is described as being due to the increasing importance of a particular recombination centre in the luminescence emission process as a result of dynamic hole transfer between non-radiative and radiative luminescence centres

A luminescence imaging system based on a CCD camera

DEFF Research Database (Denmark)

Duller, G.A.T.; Bøtter-Jensen, L.; Markey, B.G.

1997-01-01

Stimulated luminescence arising from naturally occurring minerals is likely to be spatially heterogeneous. Standard luminescence detection systems are unable to resolve this variability. Several research groups have attempted to use imaging photon detectors, or image intensifiers linked...... to photographic systems, in order to obtain spatially resolved data. However, the former option is extremely expensive and it is difficult to obtain quantitative data from the latter. This paper describes the use of a CCD camera for imaging both thermoluminescence and optically stimulated luminescence. The system...

Luminescent microporous metal–organic framework with functional Lewis basic sites on the pore surface: Quantifiable evaluation of luminescent sensing mechanisms towards Fe{sup 3+}

Energy Technology Data Exchange (ETDEWEB)

Jin, Jun-Cheng [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069 (China); Technology Promotion Center of Nano Composite Material of Biomimetic Sensor and Detecting Technology, Preparation and Application, Anhui Provincial Laboratory West Anhui University, Anhui 237012 (China); Guo, Rui-Li; Zhang, Wen-Yan [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069 (China); Jiang, Chen [Technology Promotion Center of Nano Composite Material of Biomimetic Sensor and Detecting Technology, Preparation and Application, Anhui Provincial Laboratory West Anhui University, Anhui 237012 (China); Wang, Yao-Yu, E-mail: wyaoyu@nwu.edu.cn [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069 (China)

2016-11-15

A systematic study has been conducted on a novel luminescent metal-organic framework, ([Zn(bpyp)(L-OH)]·DMF·2H{sub 2}O){sub n} (1), to explore its sensing mechanisms to Fe{sup 3+}. Structure analyses show that compound 1 exist pyridine N atoms and -OH groups on the pore surface for specific sensing of metal ions via Lewis acid-base interactions. On this consideration, the quenching mechanisms are studied and the processes are controlled by multiple mechanisms in which dynamic and static mechanisms are calculated, achieving the quantification evaluation of the quenching process. This work not only achieves the quantitative evaluation of the luminescence quenching but also provides certain insights into the quenching process, and the possible mechanisms explored in this work may inspire future research and design of target luminescent metal-organic frameworks (LMOFs) with specific functions. - Graphical abstract: A systematic study has been conducted on a novel luminescent metal-organic framework to explore its sensing mechanisms to Fe{sup 3+}. The quenching mechanisms are studied and the processes are controlled by multiple mechanisms in which dynamic and static mechanisms are calculated, achieving the quantification evaluation of the quenching process. - Highlights: • A novel porous luminescent MOF containing uncoordinated groups in interlayer channels was successfully synthesized. • The compound 1 can exhibit significant luminescent sensitivity to Fe{sup 3+}, which make its good candidate as luminescent sensor. • The corresponding dynamic and static quenching constants are calculated, achieving the quantification evaluation of the quenching process.

Spatially-resolved measurement of optically stimulated luminescence and time-resolved luminescence

International Nuclear Information System (INIS)

Bailiff, I.K.; Mikhailik, V.B.

2003-01-01

Spatially-resolved measurements of optically stimulated luminescence (OSL) were performed using a two-dimensional scanning system designed for use with planar samples. The scanning system employs a focused laser beam to stimulate a selected area of the sample, which is moved under the beam by a motorised stage. Exposure of the sample is controlled by an electronic shutter. Mapping of the distribution of OSL using a continuous wave laser source was obtained with sub-millimeter resolution for samples of sliced brick, synthetic single crystal quartz, concrete and dental ceramic. These revealed sporadic emission in the case of brick or concrete and significant spatial variation of emission for quartz and dental ceramic slices. Determinations of absorbed dose were performed for quartz grains within a slice of modern brick. Reconfiguration of the scanner with a pulsed laser source enabled quartz and feldspathic minerals within a ceramic sample to be thinner region. about 6 nm from the extrapolation of themeasuring the time-resolved luminescence spectrum

Quantitative analysis of time-resolved infrared stimulated luminescence in feldspars

DEFF Research Database (Denmark)

Pagonis, Vasilis; Ankjærgaard, Christina; Jain, Mayank

2016-01-01

Time-resolved infrared-stimulated luminescence (TR-IRSL) from feldspar samples is of importance in the field of luminescence dating, since it provides information on the luminescence mechanism in these materials. In this paper we present new analytical equations which can be used to analyze TR-IR....... The equations are applied to experimental TR-IRSL data of natural feldspars, and good agreement is found between experimental and modeling results....

Luminescence from cavitation bubbles deformed in uniform pressure gradients

Science.gov (United States)

Supponen, Outi; Obreschkow, Danail; Kobel, Philippe; Farhat, Mohamed

2017-09-01

Presented here are observations that demonstrate how the deformation of millimetric cavitation bubbles by a uniform pressure gradient quenches single-collapse luminescence. Our innovative measurement system captures a broad luminescence spectrum (wavelength range, 300-900 nm) from the individual collapses of laser-induced bubbles in water. By varying the bubble size, driving pressure, and perceived gravity level aboard parabolic flights, we probed the limit from aspherical to highly spherical bubble collapses. Luminescence was detected for bubbles of maximum radii within the previously uncovered range, R0=1.5 -6 mm, for laser-induced bubbles. The relative luminescence energy was found to rapidly decrease as a function of the bubble asymmetry quantified by the anisotropy parameter ζ , which is the dimensionless equivalent of the Kelvin impulse. As established previously, ζ also dictates the characteristic parameters of bubble-driven microjets. The threshold of ζ beyond which no luminescence is observed in our experiment closely coincides with the threshold where the microjets visibly pierce the bubble and drive a vapor jet during the rebound. The individual fitted blackbody temperatures range between Tlum=7000 and Tlum=11 500 K but do not show any clear trend as a function of ζ . Time-resolved measurements using a high-speed photodetector disclose multiple luminescence events at each bubble collapse. The averaged full width at half-maximum of the pulse is found to scale with R0 and to range between 10 and 20 ns.

Efficient and thermally stable red luminescence from nano-sized phosphor of Gd6MoO12:Eu3+

International Nuclear Information System (INIS)

Qin, Lin; Wei, Donglei; Huang, Yanlin; Kim, Sun Il; Yu, Young Moon; Seo, Hyo Jin

2013-01-01

A novel red-emitting nano-phosphor of Eu 3+ -doped Gd 6 MoO 12 was successfully synthesized by the Pechini method. The crystalline phase was confirmed by X-ray powder diffraction analysis. The morphology of the nano-phosphor was analyzed by scanning electron microscopy, indicating a good crystallization with particles smaller than 500 nm. The luminescence properties such as photoluminescence spectra and decay curves were investigated. The phosphors can be efficiently excited by near-ultraviolet (near-UV) light and exhibit a bright red luminescence around 613 nm ascribed to the forced electric dipole transition 5 D 0 → 7 F 2 of Eu 3+ ions. The thermal stabilities were investigated from the temperature-dependent luminescence decay curves (lifetimes) and spectra intensities. The luminescence properties in relation to applications in white light-emitting diodes (W-LEDs) such as the absolute luminescence quantum efficiency, excitation wavelength, and color coordinates were discussed. The Gd 6 MoO 12 :Eu 3+ nano-phosphor is a promising red-emitting candidate for the fabrication of W-LEDs with near-UV chips

Study on the relationship of protease production and luminescence in Vibrio harveyi.

Science.gov (United States)

Nakayama, T; Nomura, N; Matsumura, M

2006-07-01

To demonstrate that Vibrio harveyi produces various types of toxins and how the production of those toxins is related with luminescence. Luminescence and toxicity of eight V. harveyi were evaluated. We demonstrated that all V. harveyi emitting luminescence were isolated from marine organisms and also showed that they were highly pathogenic when compared with culture collection V. harveyi based on cytotoxic assay test. On the contrary, V. harveyi isolated from shrimp farm showed no luminescence but showed high pathogenicity based on toxicity test. The effect of protease inhibitors on pathogenicity and luminescence was also investigated. We demonstrated that light emission of pathogenic V. harveyi remarkably decreased after addition of protease inhibitor. Furthermore, extracellular proteins from cell-free culture supernatant of luminescent and nonluminescent V. harveyi were compared using SDS-PAGE analysis. Results showed that there were differences in molecular weight and amount of proteins. Vibrio harveyi parasiting marine organisms have both luminescence and pathogenicity. Based on this study, luminescence and protease toxin activity in V. harveyi are related. Moreover, this paper clarified that V. harveyi produces various types of toxins. The current study demonstrated that V. harveyi produces two kinds of toxins, haemolysin and protease toxin. It may be clear roots of V. harveyi toxin.

f-state luminescence of lanthanide and actinide ions in solution

International Nuclear Information System (INIS)

Beitz, J.V.

1993-01-01

Detailed studies of the luminescence of aquated Am 3+ are presented in the context of prior lanthanide and actinide ion work. The luminescing state of aquated Am 3+ is confirmed to be 5 D l based on observed emission and excitation spectra. The luminescence lifetime of Am 3+ in H 2 O solution is (22 ± 3) ns and (155 ± 4) ns in D 2 O solution at 295 K. Judd-Ofelt transition intensity theory qualitatively describes the observed Am 3+ relative integrated fluorescence intensities. Recent luminescence studies on complexed trivalent f-element ions in solution are reviewed as to the similarities and differences between lanthanide ion 4f state and actinide ion 5f state properties

Co-seismic luminescence in Lima, 150 km from the epicenter of the Pisco, Peru earthquake of 15 August 2007

Directory of Open Access Journals (Sweden)

J. A. Heraud

2011-04-01

Full Text Available The first photographs of Co-seismic Luminescence, commonly known as Earthquake lights (EQLs, were reported in 1968 in Japan. However, there have been documented reports of luminescence associated with earthquakes since ancient times in different parts of the world. Besides this, there is modern scientific work dealing with evidence of and models for the production of such lights. During the Peru 15 August 2007 M_w=8.0 earthquake which occurred at 06:40 p.m. LT, hence dark in the southern wintertime, several EQLs were observed along the Peruvian coast and extensively reported in the capital city of Lima, about 150 km northwest of the epicenter. These lights were video-recorded by a security camera installed at the Pontificia Universidad Catolica del Peru (PUCP campus and time-correlated with seismic ground accelerations registered at the seismological station on campus, analyzed and related to highly qualified eyewitness observations of the phenomena from other parts of the city and to other video recordings. We believe the evidence presented here contributes significantly to sustain the hypothesis that electromagnetic phenomena related to seismic activity can occur, at least during an earthquake. It is highly probable that continued research in luminescence and the use of magnetometers in studying electromagnetic activity and radon gas emanation detectors will contribute even more towards determining their occurrence during and probably prior to seismic activity.

Improved scintillation luminescence and thermal stability of In{sub 2}Si{sub 2}O{sub 7} ceramic phosphor

Energy Technology Data Exchange (ETDEWEB)

Xu, Jian; Cao, Lei; Feng, Yongyi [State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Huang, Yanlin, E-mail: hang@suda.edu.cn [State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Wang, Yaorong [State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Qin, Lin [Department of Physics and Interdisciplinary Program of Biomedical, Mechanical & Electrical Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of); Seo, Hyo Jin, E-mail: hjseo@pknu.ac.kr [Department of Physics and Interdisciplinary Program of Biomedical, Mechanical & Electrical Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of)

2017-03-15

In{sub 2}Si{sub 2}O{sub 7} is a known indium-based scintillator with fast ultraviolet photoluminescence. Unfortunately the emission only can be detected below 200 K. the poor thermal stability limits its application at room temperature. In this work, the luminescence improvement of In{sub 2}Si{sub 2}O{sub 7} was realized by F{sup −}-ions doping in the lattices. The ceramic phosphors were via typical solid-state reaction method. The pure crystalline phase with thortveirite-type structure was confirmed by X-ray diffraction (XRD) Rietveld refinements. The photoluminescence (PL) emission and excitation spectra together with the luminescence thermal stability were tested. The fluorescence decay curves CIE emission Stokes shifts were measured. The ceramic samples could present blue luminescence with maximum wavelength at about 340 nm under the excitation of UV light or high energy X-ray irradiation. The pure sample only presents luminescence below 200 K, however, the F-doping can be greatly enhance the luminescence thermal stability. The F-doped In{sub 2}Si{sub 2}O{sub 7} could present emission signals with fast decay lifetime of 850 ns at room temperature. The luminescence transitions from the In{sup 3+}-O{sup 2−} charge transfer (CT) were discussed on the structure properties.

Silica-modified luminescent LaPO4 :Eu@LaPO4 @SiO2 core/shell nanorods: Synthesis, structural and luminescent properties.

Science.gov (United States)

Ansari, Anees A

2018-02-01

Monoclinic-type tetragonal LaPO 4 :Eu (core) and LaPO 4 :Eu@LaPO 4 (core/shell) nanorods (NRs) were successfully prepared using a urea-based co-precipitation process under ambient conditions. An amorphous silica layer was coated around the luminescent core/shell NRs via the sol-gel process to improve their solubility and colloidal stability in aqueous and non-aqueous media. The prepared nano-products were systematically characterized by X-ray diffraction pattern, transmission electron microscopy, energy dispersive X-ray analysis, and FTIR, UV/Vis, and photoluminescence spectroscopy to examine their phase purity, crystal phase, surface chemistry, solubility and luminescence characteristics. The length and diameter of the nano-products were in the range 80-120 nm and 10-15 nm, respectively. High solubility of the silica-modified core/shell/Si NRs was found for the aqueous medium. The luminescent core NRs exhibited characteristic excitation and emission transitions in the visible region that were greatly affected by surface growth of insulating LaPO 4 and silica layers due to the multiphonon relaxation rate. Our luminescence spectral results clearly show a distinct difference in intensities for core, core/shell, and core/shell/Si NRs. Highly luminescent NRs with good solubility could be useful candidates for a variety of photonic-based biomedical applications. Copyright © 2017 John Wiley & Sons, Ltd.

Holographic patterning of luminescent photopolymer nanocomposites

International Nuclear Information System (INIS)

Sakhno, Oksana V.; Smirnova, Tatiana N.; Goldenberg, Leonid M.; Stumpe, Joachim

2008-01-01

Volume phase gratings in the photopolymerisable composites, containing luminescent nanoparticles have been fabricated for the first time. Nanoparticles of LaPO 4 , doped by Ce 3+ and Tb 3+ ions (the trade name is REN-X-green) with high luminescence quantum yield were used as a luminescent inorganic additive. The holographic gratings in such materials are formed as a result of the diffusion distribution of the nanoparticles during exposure of photopolymerisable composites to interference pattern. The influence of the pre-polymer formulation and the holographic patterning parameters on the grating formation is comprehensively investigated. The use of the optimised pre-polymer syrup containing two monomers with sufficiently different polymerisation rates allows fabrication of gratings with diffraction efficiency up to 80% at low optical losses (< 5%) (20 μm film thickness). To obtain maximum diffraction efficiency the intensity and the period of the interference pattern were optimised for each formulation. In addition maximum diffraction efficiency was achieved with the nanocomposites containing 30-32 wt.% of nanoparticles. On the other hand the highest possible modulation of the nanoparticles' concentration was obtained for the concentration of about 20 wt.%. In this case maximum ordering of the nanoparticles in the polymer matrix is achieved. The photoluminescence of the nanoparticles within the homogeneous polymer film and within the grating has been measured. The example application of the photopolymerisable composite containing luminescence inorganic nanoparticles in holographic security technology has been demonstrated

A new method for measuring bioturbation rates in sandy tidal flat sediments based on luminescence dating

DEFF Research Database (Denmark)

Madsen, Anni T.; Murray, Andrew S.; Jain, Mayank

2011-01-01

The rates of post-depositional mixing by bioturbation have been investigated using Optically Stimulated Luminescence (OSL) dating in two sediment cores (BAL2 and BAL5), retrieved from a sandy tidal flat in the Danish part of the Wadden Sea. A high-resolution chronology, consisting of thirty-six OSL...

Infrared (IR) stimulated luminescence from modern bricks in retrospective dosimetry applications

International Nuclear Information System (INIS)

Niedermayer, M.; Goeksu, H.Y.; Dalheimer, A.; Bayer, A.

2000-01-01

It has frequently been observed that certain roof tiles and bricks, especially from relatively modern European buildings, do not contain enough quartz grains in a suitable grain size range to permit dose reconstruction using thermoluminescence (TL) or optically stimulated luminescence (OSL) methods. In this paper the feasibility of using infrared-stimulated luminescence (IRSL) on the feldspar fraction of such bricks and tiles has been investigated. Appropriate preheating treatments were employed in order to select the most stable signals, and procedures were developed to enhance the signal to noise ratio. The possible effect of anomalous fading under application of these procedures was tested. In the dose range above 100 mGy, it has been demonstrated that using IRSL on the feldspar fraction of such material provides a feasible alternative to the use of green-light-stimulated luminescence (GLSL) on the quartz fraction, for the purposes of retrospective dosimetry. Furthermore, since the use of IRSL as described in this paper involves the measurement of polymineral fine grain fractions of bricks, a technique for the calibration of the built-in β source against the γ source in Secondary Standard Dosimetry facilities for routine use of the technique is described

Thermal dependence of luminescence lifetimes and radioluminescence in quartz

Energy Technology Data Exchange (ETDEWEB)

Pagonis, V., E-mail: vpagonis@mcdaniel.edu [McDaniel College, Physics Department, Westminster, MD 21157 (United States); Chithambo, M.L. [Department of Physics and Electronics, Rhodes University, PO BOX 94, Grahamstown 6140 (South Africa); Chen, R. [Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978 (Israel); Chruścińska, A. [Institute of Physics, Nicholas Copernicus University, 87-100 Toruń (Poland); Fasoli, M. [Department of Materials Science, University of Milano-Bicocca, Via Cozzi 53, 20125 Milano (Italy); Li, S.H. [Department of Earth Sciences, The University of Hong Kong (Hong Kong); Martini, M. [Department of Materials Science, University of Milano-Bicocca, Via Cozzi 53, 20125 Milano (Italy); Ramseyer, K. [Institut für Geologie, Baltzerstrasse 1-3, 3012 Bern (Switzerland)

2014-01-15

During time-resolved optical stimulation experiments (TR-OSL), one uses short light pulses to separate the stimulation and emission of luminescence in time. Experimental TR-OSL results show that the luminescence lifetime in quartz of sedimentary origin is independent of annealing temperature below 500 °C, but decreases monotonically thereafter. These results have been interpreted previously empirically on the basis of the existence of two separate luminescence centers L{sub H} and L{sub L} in quartz, each with its own distinct luminescence lifetime. Additional experimental evidence also supports the presence of a non-luminescent hole reservoir R, which plays a critical role in the predose effect in this material. This paper extends a recently published analytical model for thermal quenching in quartz, to include the two luminescence centers L{sub H} and L{sub L}, as well as the hole reservoir R. The new extended model involves localized electronic transitions between energy states within the two luminescence centers, and is described by a system of differential equations based on the Mott–Seitz mechanism of thermal quenching. It is shown that by using simplifying physical assumptions, one can obtain analytical solutions for the intensity of the light during a TR-OSL experiment carried out with previously annealed samples. These analytical expressions are found to be in good agreement with the numerical solutions of the equations. The results from the model are shown to be in quantitative agreement with published experimental data for commercially available quartz samples. Specifically the model describes the variation of the luminescence lifetimes with (a) annealing temperatures between room temperature and 900 °C, and (b) with stimulation temperatures between 20 and 200 °C. This paper also reports new radioluminescence (RL) measurements carried out using the same commercially available quartz samples. Gaussian deconvolution of the RL emission spectra was

Effect of retrapping on the persistent luminescence in strontium silicate orange–yellow phosphor

Energy Technology Data Exchange (ETDEWEB)

Xu, Xuhui; Yu, Xue, E-mail: yuyu6593@126.com; Zhou, Dacheng; Qiu, Jianbei, E-mail: qiu@kmust.edu.cn

2013-10-15

The orange–yellow long persistent luminescence in Sr{sub 3}SiO{sub 5}:Eu{sup 2+}, Er{sup 3+} with the chromaticity coordination of (0.48, 0.49) can persist for over 20 h above the recognizable intensity level (≥0.32 mcd/m{sup 2}) because of retrapping carriers by the deep traps. The incorporation of Er{sup 3+} into Sr{sub 3}SiO{sub 5}:Eu{sup 2+} generates a large number of shallow traps responsible for the fast decay component as well as deep traps responsible for the decay tail of the LPL. It demonstrates that the retrapping of the carrier released from a trap plays an important role in the persistent luminescence process. - Graphical abstract: LPL decay curves of Sr{sub 3−x−y}SiO{sub 5}:xEu{sup 2+}, yEr{sup 3+} (x=0.0025, y=0, 0.0025). Inset: Orange–yellow emission images recorded using a classic Reflex digital camera with exposure times varying with the persistent luminescence times. Display Omitted - Highlights: • The persistence time of Sr{sub 3}SiO{sub 5}:Eu{sup 2+}, Er{sup 3+} lasts over 20 h above the recognizable intensity level. • The incorporation of Er{sup 3+} into Sr{sub 3}SiO{sub 5}:Eu{sup 2+} generates a large number of shallow traps. • The experimental results provide an evidence for the retrapping process in LPL processes.

Phosphorescence quantum yield determination with time-gated fluorimeter and Tb(III)-acetylacetonate as luminescence reference

Energy Technology Data Exchange (ETDEWEB)

Penzkofer, A., E-mail: alfons.penzkofer@physik.uni-regensburg.de [Fakultät für Physik, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg (Germany)

2013-03-29

Highlights: ► Procedure for absolute phosphorescence quantum yield measurement is described. ► Experimental setup for absolute luminescence quantum yield standard calibration. ► Tb(acac){sub 3} proposed as phosphorescence quantum yield reference standard. ► Luminescence quantum yield of Tb(acac){sub 3} in cyclohexane measured. ► Luminescence lifetime of Tb(acac){sub 3} in cyclohexane measured. - Abstract: Phosphorescence quantum yield measurements of fluorescent and phosphorescent samples require the use of time-gated fluorimeters in order to discriminate against the fluorescence contribution. As reference standard a non-fluorescent luminescent compound is needed for absolute phosphorescence quantum yield determination. For this purpose the luminescence behavior of the rare earth chelate terbium(III)-acetylacetonate (Tb(acac){sub 3}) was studied (determination of luminescence quantum yield and luminescence lifetime). The luminescence quantum yield of Tb(acac){sub 3} was determined by using an external light source and operating the fluorimeter in chemo/bioluminescence mode with a fluorescent dye (rhodamine 6G in methanol) as reference standard. A procedure is developed for absolute luminescence (phosphorescence) quantum yield determination of samples under investigation with a time-gated fluorimeter using a non-fluorescent luminescent compound of known luminescence quantum yield and luminescence lifetime.

Optical methods for the evaluation of lanthanide excited state thermal ionization barrier in luminescent materials

Czech Academy of Sciences Publication Activity Database

Fasoli, M.; Vedda, A.; Mihóková, Eva; Nikl, Martin

2012-01-01

Roč. 85, č. 8 (2012), "085127-1"-"085127-8" ISSN 1098-0121 R&D Projects: GA AV ČR KAN300100802; GA MŠk(CZ) ME10084 Institutional research plan: CEZ:AV0Z10100521 Keywords : Lu 2 Si 2 O 7 * Pr-doped * luminescence * scintillator * excited state ionization Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.767, year: 2012

Luminescent nanocrystals in the rare-earth niobate–zirconia system formed via hydrothermal method

International Nuclear Information System (INIS)

Hirano, Masanori; Dozono, Hayato

2013-01-01

Luminescent nanocrystals based on the rare-earth niobates (Ln 3 NbO 7 , Ln=Y, Eu) and zirconia (ZrO 2 ) that were composed of 50 mol% Ln 3 NbO 7 and 50 mol% ZrO 2 , were hydrothermally formed as cubic phase under weakly basic conditions at 240 °C. The lattice parameter of the as-prepared nanoparticles corresponding to the composition of Y 3−x Eu x NbO 7 –4ZrO 2 that was estimated as a single phase of cubic gradually increased as the content of europium x increased. The existence of small absorbance peaks at 395 and 466 nm corresponding to the Eu 3+7 F 0 → 5 L 6 , and 7 F 0 → 5 D 2 excitation transition, respectively, was clearly observed in the diffuse reflectance spectra of the as-prepared samples containing europium. The optical band gap of the as-prepared samples was in the range from 3.5 to 3.7 eV. The photoluminescence spectra of the as-prepared nanocrystals containing europium showed orange and red luminescences with main peaks at 590 and 610 nm, corresponding to 5 D 0 → 7 F 1 and 5 D 0 → 7 F 2 transitions of Eu 3+ , respectively, under excitation at 395 nm Xe lamp. The emission intensity corresponding to 5 D 0 → 7 F 2 transition increased as heat-treatment temperature rose from 800 to 1200 °C. - Graphical abstract: This graphical abstract shows the excitation and emission spectra and a transmission electron microscopy image of nanocrystals (with composition based on the rare-earth niobates (Ln 3 NbO 7 , Ln=Y, Eu) and zirconia (ZrO 2 ) that were composed of 50 mol% Ln 3 NbO 7 and 50 mol% ZrO 2 ) formed via hydrothermal route. Display Omitted - Highlights: • Nanocrystals composed of 50 mol% Y 3−x Eu x NbO 7 and 50 mol% ZrO 2 was directly formed. • The nanocrystals were hydrothermally formed under weakly basic conditions at 240 °C. • The Y 3 NbO 7 showed an UV-blue and broad-band emission under excitation at 240 nm. • The emission is originated from the niobate octahedral group [NbO 6 ] 7− . • The nanocrystals showed orange and

Luminescence study of Eu3+ doped GdVO4 nanoparticles: Concentration, particle size, and core/shell effects

Science.gov (United States)

Singh, N. Shanta; Ningthoujam, R. S.; Devi, L. Romila; Yaiphaba, N.; Sudarsan, V.; Singh, S. Dorendrajit; Vatsa, R. K.; Tewari, R.

2008-11-01

Nanoparticles of GdVO4 doped with Eu3+ and core/shell of GdVO4:Eu3+/GdVO4 are prepared by urea hydrolysis method using ethylene glycol as capping agent as well as reaction medium at 130 °C. Unit cell volume increases when GdVO4 is doped with Eu3+ indicating the substitution of Gd3+ lattice sites by Eu3+. From luminescence study, it is confirmed that there is no particle size effect on emission positions of Eu3+. Optimum luminescence intensity is found to be in 5-10 at. % Eu3+. Above these concentrations, luminescence intensity decreases due to concentration quenching effect. There is an enhancement in luminescence intensity of core/shell nanoparticles. This has been attributed to the reduction in surface inhomogenities of Eu3+ surroundings by bonding to GdVO4 shell. The lifetime for D50 level increases with annealing and core/shell formation.

An alkaline one-pot reaction to synthesize luminescent Eu-BTC MOF nanorods, highly pure and water-insoluble, under room conditions

Energy Technology Data Exchange (ETDEWEB)

Medina-Velazquez, D. Y., E-mail: dyolotzin@correo.azc.uam.mx; Alejandre-Zuniga, B. Y.; Loera-Serna, S.; Ortiz, E. M. [Universidad Autónoma Metropolitana-Azcapotzalco, División de Ciencias Básicas e Ingeniería (Mexico); Morales-Ramirez, A. de J. [CIITEC IPN, Instituto Politécnico Nacional (Mexico); Garfias-Garcia, E. [Universidad Autónoma Metropolitana-Azcapotzalco, División de Ciencias Básicas e Ingeniería (Mexico); Garcia-Murillo, A. [CIITEC IPN, Instituto Politécnico Nacional (Mexico); Falcony, C. [Centro de Investigación y Estudios Avanzados, Departamento de Física (Mexico)

2016-12-15

The increasing demand for optoelectronic devices requires the development of luminescent materials with high luminescence efficiency and low energy demands, and the metalorganic frameworks (MOFs) with lanthanides ions offer great potential in this area. The metalorganic materials provide properties of flexibility, low density, low-cost methods of synthesis, and insolubility in water, which gives them an advantage over traditional phosphors. In this study, a benzenetricarboxylate ligand (BTC) with a Eu{sup 3+} MOF was synthesized, and its structural and luminescent properties were measured. The metalorganic compound was generated in a one-pot reaction from europium nitrate and trimesic acid precursors. Through characterization by X-ray diffraction powder, infrared spectroscopy, SEM structural characterization, and luminescent spectroscopy, the formation of Europium benzenetricarboxylate (Eu-BTC) MOF nanorods was tested and the calculated value was in the range of 30–60 nm. A red luminescent emission with high intensity was observed for all the procedures.

Thermally stimulated luminescence in ZnMoO{sub 4} crystals

Energy Technology Data Exchange (ETDEWEB)

Degoda, V.Ya.; Kogut, Ya.P.; Moroz, I.M. [Kyiv National Taras Shevchenko University, MSP 03680 Kyiv (Ukraine); Danevich, F.A. [Institute for Nuclear Research, MSP 03680 Kyiv (Ukraine)

2017-03-15

Thermally stimulated luminescence in ZnMoO{sub 4} crystals after X-ray irradiation at temperatures 8 K, 85 K and 295 K was studied. A theoretical model of crystal phosphor with three types of traps (shallow, phosphorescent and deep) is proposed. Simple analytic solutions of the kinetic equations system describing localized electrons on the traps and holes on recombination centres were obtained by using approximations accepted in the classic theories of crystal phosphors. Analytical curves describing thermally stimulated luminescence were obtained. A substantial effect of the different traps concentrations ratios on the thermally stimulated luminescence and conductivity peaks shapes is shown. A good agreement of the theoretical curves with the experimental data for the thermally stimulated luminescence peak at 114 K is obtained.

Influence of Nano sized Silicon Oxide on the Luminescent Properties of Zn O Nanoparticles

International Nuclear Information System (INIS)

Shvalagin, V.; Grodziuk, G.; Kurmach, M.; Granchak, V.; Sarapulova, O.; Sherstiuk, V.

2016-01-01

For practical use of nano sized zinc oxide as the phosphor its luminescence quantum yields should be maximized. The aim of this work was to enhance luminescent properties of Zn O nanoparticles and obtain high-luminescent Zn O/SiO 2 composites using simpler approaches to colloidal synthesis. The luminescence intensity of zinc oxide nanoparticles was increased about 3 times by addition of silica nano crystals to the source solutions during the synthesis of Zn O nanoparticles. Then the quantum yield of luminescence of the obtained Zn O/SiO 2 composites is more than 30%. Such an impact of silica is suggested to be caused by the distribution of Zn O nano crystals on the surface of silica, which reduces the probability of separation of photo generated charges between the zinc oxide nanoparticles of different sizes, and as a consequence, there is a significant increase of the luminescence intensity of Zn O nanoparticles. This way of increasing nano-Zn O luminescence intensity facilitates its use in a variety of devices, including optical ultraviolet and visible screens, luminescent markers, antibacterial coatings, luminescent solar concentrators, luminescent inks for security printing, and food packaging with abilities of informing consumers about the quality and safety of the packaged product.

Luminescence and luminescence quenching of Eu{sub 2}Mo{sub 4}O{sub 15}

Energy Technology Data Exchange (ETDEWEB)

Janulevicius, Matas; Grigorjevaite, Julija; Merkininkaite, Greta [Department of Analytical and Environmental Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius (Lithuania); Sakirzanovas, Simas [Department of Applied Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius (Lithuania); Katelnikovas, Arturas, E-mail: arturas.katelnikovas@chf.vu.lt [Department of Analytical and Environmental Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius (Lithuania)

2016-11-15

A polycrystalline Eu{sub 2}Mo{sub 4}O{sub 15} phosphor sample was prepared by high temperature solid state reaction. Phase purity and morphological features of the phosphor were investigated by X-ray diffraction and scanning electron microscopy, respectively. Reflectance spectra showed that the optical band gap of Eu{sub 2}Mo{sub 4}O{sub 15} is 2.95 eV. Phosphor emits intensive red light when excited with 394 and 465 nm radiation. Temperature dependent emission and luminescence lifetime measurements revealed that external and internal quantum yields decrease at the same rate and that luminescence quenches due to photoionization. The calculated external quantum yields for 394 and 465 nm excitation were 7.8% and 53.5%, respectively.

Analyte-triggered luminescence of Eu{sup 3+} ions encapsulated in Nafion membranes -preparation of hybrid materials from in membrane chemical reactions-

Energy Technology Data Exchange (ETDEWEB)

Aguilar-Sánchez, Rocío, E-mail: raguilar@ifuap.buap.mx [Depto. Química Analítica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla 72570 (Mexico); Zelocualtecatl-Montiel, Iván [Depto. Química Analítica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla 72570 (Mexico); Gálvez-Vázquez, María de Jesús [Depto. Química Analítica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla 72570 (Mexico); Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado postal J-48, Puebla 72570 (Mexico); Silva-González, Rutilo [Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado postal J-48, Puebla 72570 (Mexico)

2017-04-15

The possibility to perform chemical reactions inside polymer materials opens a unique opportunity to control and prepare materials for diverse solid-state applications. Based on the affinity of Eu{sup 3+} ions for oxygen functionalities, in this work we report the luminescence enhancement of Eu{sup 3+} ions inserted in Nafion membranes (Naf/Eu{sup 3+}) by in-situ complexing to oxalate. The formation of a europium-oxalate type complex enhances Eu{sup 3+} luminescence emission, which could be exploited for the construction of devices for oxalate sensing and the fabrication of highly luminescent materials. Possible analytical applications of Naf/Eu{sup 3+} membranes were evaluated by fluorescence spectroscopy through the linear response with concentration. The complex formation was followed by infrared spectroscopy and SEM-EDS analysis. - Highlights: • Luminescence enhancement by complexation of Eu{sup 3+} ions to oxalate inside Nafion. • Performance of chemical reactions inside Nafion/polymer membranes. • An easy and novel method to prepare luminescent solid devices. • Possibility to develop luminescent sensors by analyte-triggered optical response.

Influence of ionizing radiation on biogel bone implants observed by luminescence measurements

International Nuclear Information System (INIS)

Szarska, St.; Jungner, H.; Borsowska, A.

2004-01-01

The preparation of sol-gel-derived bioactive glass thin films coated on glass is described. Biogel is one of the important modern materials, which are applied in medicine to reduce disability and thus to improve the level of human life. A patient with implanted biogel (i.e. bone, tooth) may be subjected to ionizing radiation during X-ray examination or treatment of cancer. Such an irradiation can generate electron and hole traps in the insulator surface layer. Changes in the microstructure of the biogel surface resulting from irradiation were observed using luminescence methods. Results from luminescence measurements after irradiation of a set of biogel samples are discussed in terms of point defects in the glass structure

The application of time-resolved luminescence spectroscopy to a remote uranyl sensor

International Nuclear Information System (INIS)

Varineau, P.T.; Duesing, R.; Wangen, L.E.

1991-01-01

Time resolved luminescence spectroscopy is an effective method for the determination of a wide range of uranyl concentrations in aqueous samples. We have applied this technique to the development of a remote sensing device using fiber optic cables coupled with a micro flow cell in order to probe for uranyl in aqueous samples. This sensor incorporates a Nafion membrane through which UO 2 2+ can diffuse in to a reaction/analysis chamber which holds phosphoric acid, a reagent which enhances the uranyl luminescence intensity and lifetime. With this device, anionic and fluorescing organic interferences could be eliminated, allowing for the determination of uranyl over a concentration range of 10 4 to 10 -9 M. 17 refs., 5 figs

Piezoelectrically-induced stress-luminescence phenomenon in CaAl2O4:Eu2+

International Nuclear Information System (INIS)

Wei, Yongbin; Wu, Zheng; Jia, Yanmin; Liu, Yongsheng

2015-01-01

Piezoelectrically-induced stress-luminescence in the CaAl 2 O 4 :Eu 2+ was investigated. Blue light that was visible to the naked eye could be observed in the dark when a pulse force of ∼7.7 kN was applied to the sample. The intensity of the stress-luminescence strongly depended on the magnitude of the applied force during a pulse cycle. The intensity decreased with repetitive application of pulse stress and was completely recovered after irradiation with ultraviolet light. It is suggested that the stress-luminescence effect in CaAl 2 O 4 :Eu 2+ arises from the piezoelectrically-induced de-trapping of the charge carriers. A CaAl 2 O 4 :Eu 2+ ceramic that exhibits a stress-luminescence effect has potential applications in smart stress optically-sensing devices. - Highlights: • The strong induced stress-luminescence in CaAl 2 O 4 :Eu 2+ was observed. • The stress-luminescent intensity strongly depends on the magnitude of force. • The stress-luminescence could be completely recovered after the UV irradiation. • The strong stress-luminescent effect is potential in stress-light sensors

Luminescence dating of Late Quaternary sediments from East Greenland

DEFF Research Database (Denmark)

Mejdahl, V.; Funder, Svend Visby

1994-01-01

Luminescence dating based on K-feldspars and using both TL and OSL methods have been performed on 94 sediment samples from East Greenland. The ages go back more than 380 ka, but are mainly from the last interglaciation and the subsequent period and include both shallow-marine/coastal-fluvial and ...... owing to incomplete bleaching. OSL may give better results than TL in these sediments...

Synthesis, characterisation and functionalisation of luminescent silica nanoparticles

International Nuclear Information System (INIS)

Labéguerie-Egéa, Jessica; McEvoy, Helen M.; McDonagh, Colette

2011-01-01

The synthesis of highly monodispersed, homogeneous and stable luminescent silica nanoparticles, synthesized using a process based on the Stöber method is reported here. These particles have been functionalised with the ruthenium and europium complexes: bis (2,2′-bipyridine)-(5-aminophenanthroline) Ru bis (hexafluorophosphate), abbreviated to (Ru(bpy) 2 (phen-5-NH 2 )(PF 6 )), and tris (dibenzoylmethane)-mono (5-aminophenanthroline) europium(III), abbreviated to (Eu:TDMAP). Both dyes have a free amino group available, facilitating the covalent conjugation of the dyes inside the silica matrix. Due to the covalent bond between the dyes and the silica, no dye leaching or nanoparticle diameter modification was observed. The generic and versatile nature of the synthesis process was demonstrated via the synthesis of both europium and ruthenium-functionalised nanoparticles. Following this, the main emphasis of the study was the characterisation of the luminescence of the ruthenium-functionalised silica nanoparticles, in particular, as a function of surface carboxyl or amino group functionalisation. It was demonstrated that the luminescence of the ruthenium dye is highly affected by the ionic environment at the surface of the nanoparticle, and that these effects can be counteracted by encapsulating the ruthenium-functionalised nanoparticles in a plain 15 nm silica layer. Moreover, the ruthenium-functionalised silica nanoparticles showed high relative brightness compared to the free dye in solution and efficient functionalisation with amino or carboxyl groups. Due to their ease of fabrication and attractive characteristics, the ruthenium-functionalised silica nanoparticles described here have the potential to be highly desirable fluorescent labels, particularly, for biological applications.

Metal-enhanced luminescence: Current trend and future perspectives- A review

International Nuclear Information System (INIS)

Ranjan, Rajeev; Esimbekova, Elena N.; Kirillova, Maria A.; Kratasyuk, Valentina A.

2017-01-01

Optically enhanced biosensing strategies are prerequisites for developing miniature and highly sensitive multiplexed analytical platforms. Such smart biosensing systems are highly promising for use in the fields of biomedicine and environmental monitoring. Optical signal enhancement during bioassays is attributed to the complex opto-electronic interactions of incoming photonic signals at the nanomaterial interface. Research on the use of metals other than gold and silver for such purposes tends to extend the spectral window to observe luminescence enhancement effects. Such manifold increase in luminescence may be explained by the principles of plasmon coupling, directional emission led high collection efficiency, Rayleigh scattering and related opto-electronic events. The present review begins with a mechanistic description of important phenomena associated with metal-induced luminescence enhancement, particularly focusing on the origin of metal-enhanced luminescence. This review further analyses the hybrid nanostructure capabilities responsible for maintaining unique opto-electronic properties during bio-functionalisation. Current research trends in this area, future scope of this field for designing useful bioassays and concluding remarks are then discussed. - Highlights: • Nanomaterials significantly differ from their bulk counterparts. • Strong and pronounced photophysical effects at the metal surface provide opportunities for designing novel biosensors. • Metal-enhanced luminescence increases the quantum yield of luminescent reactions. • Under optimal conditions, plasmon coupling enhances the optical effects at the nanometal surface.

Metal-enhanced luminescence: Current trend and future perspectives- A review

Energy Technology Data Exchange (ETDEWEB)

Ranjan, Rajeev [Laboratory of Bioluminescent Biotechnologies, Department of Biophysics, Institute of Fundamental Biology and Biotechnology, Siberian Federal University, 79 Svobodny Prospect, Krasnoyarsk 660041 (Russian Federation); Esimbekova, Elena N., E-mail: esimbekova@yandex.ru [Laboratory of Bioluminescent Biotechnologies, Department of Biophysics, Institute of Fundamental Biology and Biotechnology, Siberian Federal University, 79 Svobodny Prospect, Krasnoyarsk 660041 (Russian Federation); Institute of Biophysics SB RAS, Federal Research Center “Krasnoyarsk Science Center SB RAS”, Akademgorodok 50/50, Krasnoyarsk 660036 (Russian Federation); Kirillova, Maria A. [Laboratory of Bioluminescent Biotechnologies, Department of Biophysics, Institute of Fundamental Biology and Biotechnology, Siberian Federal University, 79 Svobodny Prospect, Krasnoyarsk 660041 (Russian Federation); Kratasyuk, Valentina A. [Laboratory of Bioluminescent Biotechnologies, Department of Biophysics, Institute of Fundamental Biology and Biotechnology, Siberian Federal University, 79 Svobodny Prospect, Krasnoyarsk 660041 (Russian Federation); Institute of Biophysics SB RAS, Federal Research Center “Krasnoyarsk Science Center SB RAS”, Akademgorodok 50/50, Krasnoyarsk 660036 (Russian Federation)

2017-06-08

Optically enhanced biosensing strategies are prerequisites for developing miniature and highly sensitive multiplexed analytical platforms. Such smart biosensing systems are highly promising for use in the fields of biomedicine and environmental monitoring. Optical signal enhancement during bioassays is attributed to the complex opto-electronic interactions of incoming photonic signals at the nanomaterial interface. Research on the use of metals other than gold and silver for such purposes tends to extend the spectral window to observe luminescence enhancement effects. Such manifold increase in luminescence may be explained by the principles of plasmon coupling, directional emission led high collection efficiency, Rayleigh scattering and related opto-electronic events. The present review begins with a mechanistic description of important phenomena associated with metal-induced luminescence enhancement, particularly focusing on the origin of metal-enhanced luminescence. This review further analyses the hybrid nanostructure capabilities responsible for maintaining unique opto-electronic properties during bio-functionalisation. Current research trends in this area, future scope of this field for designing useful bioassays and concluding remarks are then discussed. - Highlights: • Nanomaterials significantly differ from their bulk counterparts. • Strong and pronounced photophysical effects at the metal surface provide opportunities for designing novel biosensors. • Metal-enhanced luminescence increases the quantum yield of luminescent reactions. • Under optimal conditions, plasmon coupling enhances the optical effects at the nanometal surface.

Influence of sample oxidation on the nature of optical luminescence from porous silicon

International Nuclear Information System (INIS)

Coulthard, I.; Antel, W. J. Jr.; Freeland, J. W.; Sham, T. K.; Naftel, S. J.; Zhang, P.

2000-01-01

Site-selective luminescence experiments were performed upon porous-silicon samples exposed to varying degrees of oxidation. The source of different luminescence bands was determined to be due to either quantum confinement in nanocrystalline silicon or defective silicon oxide. Of particular interest is the defective silicon-oxide luminescence band found at 2.1 eV, which was found to frequently overlap with a luminescence band from nanocrystalline silicon. Some of the historical confusion and debate with regards to the source of luminescence from porous silicon can be attributed to this overlap. (c) 2000 American Institute of Physics

Luminescence properties of Yb:Nd:Tm:KY3F10 nanophosphor and thermal treatment effects

International Nuclear Information System (INIS)

Gomes, Laércio; Linhares, Horácio Marconi da Silva M.D.; Ichikawa, Rodrigo Uchida; Martinez, Luis Gallego; Ranieri, Izilda Marcia

2015-01-01

In this work, we present the spectroscopic properties of KY 3 F 10 (KY3F) nanocrystals activated with thulium and codoped with ytterbium and neodymium ions. The most important processes that lead to the thulium upconversion emissions in the blue region were identified. A time-resolved luminescence spectroscopy technique was employed to measure the luminescence decays and to determine the most important mechanisms involved in the upconversion process that populates 1 G 4 (Tm 3+ ) excited states. Analysis of the energy-transfer processes dynamics using selective pulsed-laser excitations in Yb:Nd:Tm, Nd:KY3F nanocrystals shows that the direct energy transfer from Nd 3+ to Tm 3+ ions is the mechanism responsible for the 78% of the blue upconversion luminescence in the Yb:Nd:Tm:KY3F when compared with the Yb:Nd:Tm:KY3F bulk crystal for an laser excitation at 802 nm. An investigation of the 1 G 4 level luminescence kinetic of Tm 3+ in Yb/Nd/Tm system revealed that the luminescence efficiency ( 1 G 4 ) starts with a very low value (0.38%) for the synthesized nanocrystal (as grown) and strongly increases to 97% after thermal treatment at 550 °C for 6 h under argon flow. As a consequence of the thermal treatment at T=550 °C, the contributions of the (Nd×Tm) (Up 1 ) and (Nd×Yb×Tm) (Up 2 ) upconversion processes to the 1 G 4 luminescence are 33% (Up 1 ) and 67% for Up 2 . Up 2 process represented by Nd 3+ ( 4 F 3/2 )→Yb 3+ ( 2 F 7/2 ) followed by Yb 3+ ( 2 F 5/2 )→Tm ( 3 H 4 )→Tm 3+ ( 1 G 4 ) was previously reported as the main mechanism to produce the blue luminescence in Yb:Nd:Tm:YLiF 4 and KY 3 F 10 bulk crystals. Results of X-ray diffraction analysis of nanopowder using the Rietveld method reveled that crystallite sizes remain unchanged (12–14 nm) after thermal treatments with T≤400 °C, while the 1 G 4 luminescence efficiency strongly increases from 0.38% (T=25 °C) to 12% (T=400 °C). Results shown that the Nd 3+ ions distribution has a concentration

Persistent luminescence in both first and second biological windows in ZnGa2O4:Cr3+,Yb3+ glass ceramics

Science.gov (United States)

Castaing, V.; Sontakke, A. D.; Xu, J.; Fernández-Carrión, A. J.; Allix, M.; Tanabe, S.; Viana, B.

2018-02-01

ZnGa2O4:Cr3+ is an optical material well known for its deep red persistent luminescence properties which are centered in the first biological window. In this work, Yb3+, Cr3+ co-doped zinc gallate oxide has been prepared in the form of glass-ceramics. The studied samples have been elaborated via conventional melt quenching process leading to nanometer scale phase separated glass which was subsequently crystallized to obtain nanocrystals embedded in a transparent glass matrix. In these as-prepared ZnGa2O4:Cr3+,Yb3+ glass-ceramics, regular Cr3+ emission (at around 695 nm) as well as Yb3+ emission (between 950 and 1100 nm) is observed. Several photoluminescence emission and excitation experiments have been recorded in order clarify (i) the simultaneous emission of these cations in different optical windows and (ii) the energy transfer process between these two emitting centers. Further studies proved that Yb3+ is not only active in photoluminescence but also in persistent luminescence, leading to a material demonstrating persistent luminescence properties in both first and second biological windows (650-950 and 1000-1350 nm respectively). Thermoluminescence experiments have been carried out on these materials in order to gain deeper information about the persistent luminescence process.

Fiber optical dose rate measurement based on the luminescence of beryllium oxide

Directory of Open Access Journals (Sweden)

Teichmann Tobias

2018-01-01

Full Text Available This work presents a fiber optical dose rate measurement system based on the radioluminescence and optically stimulated luminescence of beryllium oxide. The system consists of a small, radiation sensitive probe which is coupled to a light detection unit with a long and flexible light guide. Exposing the beryllium oxide probe to ionizing radiation results in the emission of light with an intensity which is proportional to the dose rate. Additionally, optically stimulated luminescence can be used to obtain dose and dose rate information during irradiation or retrospectively. The system is capable of real time dose rate measurements in fields of high dose rates and dose rate gradients and in complex, narrow geometries. This enables the application for radiation protection measurements as well as for quality control in radiotherapy. One inherent drawback of fiber optical dosimetry systems is the generation of Cherenkov radiation and luminescence in the light guide itself when it is exposed to ionizing radiation. This so called “stem” effect leads to an additional signal which introduces a deviation in the dose rate measurement and reduces the spatial resolution of the system, hence it has to be removed. The current system uses temporal discrimination of the effect for radioluminescence measurements in pulsed radiation fields and modulated optically stimulated luminescence for continuous irradiation conditions. This work gives an overview of the major results and discusses new-found obstacles of the applied methods of stem discrimination.

Hormesis response of marine and freshwater luminescent bacteria to metal exposure

Directory of Open Access Journals (Sweden)

KAILI SHEN

2009-01-01

Full Text Available The stimulatory effect of low concentrations of toxic chemicals on organismal metabolism, referred to as hormesis, has been found to be common in the widely used luminescence bioassay. This paper aims to study the hormesis phenomenon in both marine and freshwater luminescent bacteria, named Photobacterium phosphorem and Vibrio qinghaiensis. The effects of Cu (II, Zn (II, Cd (II and Cr (VI on luminescence of these two bacteria were studied for 0 to 75 minutes exposure by establishing dose- and time-response curves. A clear hormesis phenomenon was observed in all four testing metals at low concentrations under the condition of luminescence assays.

Characterization and luminescent properties of Eu3+ doped Gd2Zr2O7 nanopowders

International Nuclear Information System (INIS)

Rabasovic, M.S.; Sevic, D.; Krizan, J.; Terzic, M.; Mozina, J.; Marinkovic, B.P.; Savic-Sevic, S.; Mitric, M.; Rabasovic, M.D.; Romcevic, N.

2015-01-01

Highlights: • Nanopowders Gd 2 Zr 2 O 7 doped by europium ions (Eu 3+ ) have been synthesized. • Their luminescence properties have been measured at room temperature. • The temporal evolution of laser induced phenomena are presented using time-resolved technique. • Lifetime analysis for luminescence bands in emission spectra has been done. - Abstract: Nanopowders based on gadolinium zirconium oxide (Gd 2 Zr 2 O 7 ) doped by europium ions (Eu 3+ ) were successfully prepared using a flame combustion method. This material is suitable for various optical devices. The structure of prepared materials has been confirmed and characterized using X-ray powder diffraction (XRD), scanning electron microscope (SEM) and photoluminescence (PL) techniques. The luminescence properties of synthesized nanopowders were characterized by emission spectra and luminescence lifetimes by using the streak camera system. PL spectra were obtained at three different excitation wavelengths (Optical Parametric Oscilator (OPO) at 360 nm, laser diode at 365 nm and Ar laser line at 514.5 nm). The strong emission lines at 611 nm and 630 nm corresponding to the 5 D 0 → 7 F 2 long lived transition could be used as a new red light source in optical devices

Amino-Functionalized Luminescent Metal-Organic Framework Test Paper for Rapid and Selective Sensing of SO2 Gas and Its Derivatives by Luminescence Turn-On Effect.

Science.gov (United States)

Wang, Meng; Guo, Lin; Cao, Dapeng

2018-03-06

Rapid and selective sensing of sulfur dioxide (SO 2 ) gas has attracted more and more attention because SO 2 not only causes environmental pollution but also severely affects the health of human beings. Here we report an amino-functionalized luminescent metal-organic framework (MOF) material (i.e., MOF-5-NH 2 ) and further investigate its sensing property for SO 2 gas and its derivatives as a luminescent probe. The results indicate that the MOF-5-NH 2 probe can selectively and sensitively sense SO 2 derivatives (i.e., SO 3 2- ) in real time by a luminescence turn-on effect with a lower detection limit of 0.168 ppm and a response time of less than 15 s. Importantly, the luminescence turn-on phenomenon can be observed by the naked eye. We also assembled MOF-5-NH 2 into a test paper to achieve the aim of portable detection, and the lower-limit concentration of the test paper for sensing SO 2 in real time was found to be about 0.05 ppm. Moreover, MOF-5-NH 2 also shows good anti-interference ability, strong luminescence stability, and reusability, which means that this material is an excellent sensing candidate. The amino functionalization may also provide a modification strategy to design luminescent sensors for other atmospheric pollutants.

Luminescence investigation of Yb3+/Er3+ codoped single LiYF4 microparticle

International Nuclear Information System (INIS)

Gao, Wei; Zheng, Hairong; He, Enjie; Lu, Ying; Gao, Fangqi

2014-01-01

Tetragonal phase LiYF 4 :Yb 3+ /Er 3+ microparticles are synthesized via facile hydrothermal method. Single LiYF 4 microparticle is excited with IR laser at 980 nm in a confocal setup, and strong green and weak red emissions are observed. It is found that single LiYF 4 :Yb 3+ /Er 3+ microparticle with sub-structure presents stronger upconversion luminescence emission and smaller intensity ratio of red to green emission than that from LiYF 4 :Yb 3+ /Er 3+ microparticle with no sub-structure. The possible mechanism, the influence of particle size and the existence of EDTA on the upconversion luminescence emission are investigated. The current study suggests that the luminescence observation with single micropaticle can effectively avoid the influence of environment and neighbor particles, which is important for investigating the luminescence properties of micro- or nano-crystals and for extending their application. - Highlights: • Single LiYF 4 microparticle is excited with IR laser at 980 nm in a confocal setup, and strong green and weak red emissions are observed. • Single LiYF 4 microparticle with different morphology exhibits different fluorescence emission intensity and intensity ratio of red to green emission. • The possible mechanism, the influence of particle size and the existence of EDTA on the upconversion emission are investigated

Potential and limits of OSL, TT-OSL, IRSL and pIRIR290 dating methods applied on a Middle Pleistocene sediment record of Lake El'gygytgyn, Russia

Directory of Open Access Journals (Sweden)

A. Zander

2013-03-01

Full Text Available This study tests the paleomagnetic and proxy-data based Mid- to Upper Pleistocene sediment deposition history of Lake El'gygytgyn by applying different approaches of luminescence dating techniques on sediment cores taken from the centre of the 175 m deep lake. For dating polymineral and quartz fine grains (4–11 μm grain size range were extracted from nine different levels from the upper 28 m of sediment cores 5011-1A and 5011-1B. According to the independent age model, the lowest sample from 27.8–27.9 m below lake bottom level correlates to the Brunhes-Matuyama (B/M reversal. Polymineral sub-samples were analysed by infra-red stimulated luminescence (IRSL and post-IR IRSL measured at 290 °C (pIRIR290 using single aliquot regenerative dose (SAR sequences. SAR protocols were further applied to measure the blue light optically stimulated luminescence (OSL and thermally-transferred OSL (TT-OSL of fine-grained quartz supplemented by a multiple aliquot approach. Neither low temperature IRSL measurements at 50 °C nor any OSL dating approach on quartz yielded reliable results. Deconvolution of their dose response curves revealed a pseudo-increase of the dose response curves and explains the observed underestimation. The pIRIR protocol applied to polymineral fine grains was the only luminescence technique able to provide dating results of acceptable accuracy up to ca. 700 ka when correlated to the existing proxy-data and paleomagnetic based age record. We present the potential and limits of the different dating techniques and a correlation of pIRIR290 results with the proxy-data based age model.

Hybrid model based unified scheme for endoscopic Cerenkov and radio-luminescence tomography: Simulation demonstration

Science.gov (United States)

Wang, Lin; Cao, Xin; Ren, Qingyun; Chen, Xueli; He, Xiaowei

2018-05-01

Cerenkov luminescence imaging (CLI) is an imaging method that uses an optical imaging scheme to probe a radioactive tracer. Application of CLI with clinically approved radioactive tracers has opened an opportunity for translating optical imaging from preclinical to clinical applications. Such translation was further improved by developing an endoscopic CLI system. However, two-dimensional endoscopic imaging cannot identify accurate depth and obtain quantitative information. Here, we present an imaging scheme to retrieve the depth and quantitative information from endoscopic Cerenkov luminescence tomography, which can also be applied for endoscopic radio-luminescence tomography. In the scheme, we first constructed a physical model for image collection, and then a mathematical model for characterizing the luminescent light propagation from tracer to the endoscopic detector. The mathematical model is a hybrid light transport model combined with the 3rd order simplified spherical harmonics approximation, diffusion, and radiosity equations to warrant accuracy and speed. The mathematical model integrates finite element discretization, regularization, and primal-dual interior-point optimization to retrieve the depth and the quantitative information of the tracer. A heterogeneous-geometry-based numerical simulation was used to explore the feasibility of the unified scheme, which demonstrated that it can provide a satisfactory balance between imaging accuracy and computational burden.

Analytical expressions for time-resolved optically stimulated luminescence experiments in quartz

International Nuclear Information System (INIS)

Pagonis, V.; Lawless, J.; Chen, R.; Chithambo, M.L.

2011-01-01

Optically stimulated luminescence (OSL) signals can be obtained using a time-resolved optical stimulation (TR-OSL) method, also known as pulsed OSL. During TR-OSL measurements, the stimulation and emission of luminescence are experimentally separated in time using short light pulses. This paper presents analytical expressions for the TR-OSL intensity observed during and after such a pulse in quartz experiments. The analytical expressions are derived using a recently published kinetic model which describes thermal quenching phenomena in quartz samples. In addition, analytical expressions are derived for the concentration of electrons in the conduction band during and after the TR-OSL pulse, and for the maximum signals attained during optical stimulation of the samples. The relevance of the model for dosimetric applications is examined, by studying the dependence of the maximum TR-OSL signals on the degree of initial trap filling, and also on the probability of electron retrapping into the dosimetric trap. Analytical expressions are derived for two characteristic times of the TR-OSL mechanism; these times are the relaxation time for electrons in the conduction band, and the corresponding relaxation time for the radiative transition within the luminescence center. The former relaxation time is found to depend on several experimental parameters, while the latter relaxation time depends only on internal parameters characteristic of the recombination center. These differences between the two relaxation times can be explained by the presence of localized and delocalized transitions in the quartz sample. The analytical expressions in this paper are shown to be equivalent to previous analytical expressions derived using a different mathematical approach. A description of thermal quenching processes in quartz based on AlO 4 - /AlO 4 defects is presented, which illustrates the connection between the different descriptions of the luminescence process found in the literature

Praseodymium - A Competent Dopant for Luminescent Downshifting and Photocatalysis in ZnO Thin Films

Science.gov (United States)

Narayanan, Nripasree; Deepak, N. K.

2018-05-01

Highly transparent and conducting Zinc oxide (ZnO) thin films doped with Praseodymium (Pr) were deposited on glass substrates by using the spray pyrolysis method. The X-ray diffraction (XRD) analysis revealed the polycrystallinity of the deposited films with a hexagonal wurtzite structure, whereas the energy-dispersive X-ray spectroscopy (EDX) analysis confirmed the incorporation of Pr in the films. The optical energy gap decreased by Pr doping due to the merging of the conduction band with the impurity bands formed within the forbidden gap. The room temperature photoluminescence spectra of the Pr-doped film showed enhancement of visible emission, suggesting efficient luminescent downshifting. The photocatalytic activity of the Pr-doped films is higher than that of undoped films due to the effective suppression of the rapid recombination of the photo-generated electron-hole pairs. The impurity levels formed within the forbidden gap act as efficient luminescent centers and electron traps, which lead to luminescent downshifting and enhanced photocatalytic activity.

Luminescence study of spodumene

International Nuclear Information System (INIS)

Isotani, S.; Fujii, A.T.; Antonini, R.; Pontuschka, W.M.; Rabani, S.R.; Furtado, W.W.

1990-02-01

A comparative study is made of the luminescence of five kinds of spodumene from Minas Gerais, Brazil, studied previously by optical absorption spectroscopy. Natural gemstones are used which, in the course of the experiments, were irradiated with X-rays. (L.C.) [pt

Silicon: electrochemistry and luminescence

NARCIS (Netherlands)

Kooij, Ernst Stefan

1997-01-01

The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible

Biosynthesis of myristic acid in luminescent bacteria

International Nuclear Information System (INIS)

Byers, D.M.

1987-01-01

In vivo pulse-label studies have demonstrated that luminescent bacteria can provide myritic acid (14:0) required for the synthesis of the luciferase substrate myristyl aldehyde. Luminescent wild type Vibrio harveyi incubated with [ 14 C] acetate in a nutrient-depleted medium accumulated substantial tree [ 14 C]fatty acid (up to 20% of the total lipid label). Radio-gas chromatography revealed that > 75% of the labeled fatty acid is 14:0. No free fatty acid was detected in wild type cells labeled prior to the development of bioluminescence in the exponential growth phase, or in a dark mutant of V. harveyi (mutant M17) that requires exogenous 14:0 for light emission. The preferential accumulation of 14:0 was not observed when wild type cells were labeled with [ 14 C]acetate in regular growth medium. Moreover, all V. harveyi strains exhibited similar fatty acid mass compositions regardless of the state of bioluminescence. Since earlier work has shown that a luminescence-related acyltransferase (defective in the M17 mutant) can catalyze the deacylation of fatty acyl-acyl carrier protein in vitro, the present results are consistent with a model in which this enzyme diverts 14:0 to the luminescence system during fatty acid biosynthesis. Under normal conditions, the supply of 14:0 by this pathway is tightly regulated such that bioluminescence development does not significantly alter the total fatty acid composition

Structural and luminescence properties of self-yellow emitting undoped and (Ca, Ba, Sr)-doped Zn2V2O7 phosphors synthesized by combustion method

Science.gov (United States)

Foka, Kewele E.; Dejene, Birhanu F.; Koao, Lehlohonolo F.; Swart, Hendrik C.

2018-04-01

A self-activated yellow emitting Zn2V2O7 was synthesized by combustion method. The influence of the processing parameters such as synthesis temperature and dopants concentration on the structure, morphology and luminescence properties was investigated. The X-ray diffraction (XRD) analysis confirmed that the samples have a tetragonal structure and no significant structural change was observed in varying both the synthesis temperature and the dopants concentration. The estimated average crystallite size was 78 nm for the undoped samples synthesized at different temperatures and 77 nm for the doped samples. Scanning electron microscope (SEM) images showed agglomerated hexagonal-shaped particles with straight edges at low temperatures and the shape of the particles changed to cylindrical structures at moderate temperatures. At higher temperatures, the morphology changed completely. However, the morphologies of the doped samples looked alike. The photoluminescence (PL) of the product exhibited broad emission bands ranging from 400 to 800 nm. The best luminescence intensity was observed for the undoped Zn2V2O7 samples and those synthesized at 600 ℃ . Any further increase in synthesis temperature, type and concentration of dopants led to a decrease in the luminescence intensity. The broad band emission peak of Zn2V2O7 consisted of two broad bands corresponding to emissions from the Em1 (3T2→1A1) and Em2 (3T1→1A1) transitions.

Conversion of the luminescence of laser dyes in opal matrices to stimulated emission

International Nuclear Information System (INIS)

Alimov, O K; Basiev, T T; Orlovskii, Yu V; Osiko, V V; Samoilovich, M I

2008-01-01

The luminescence and laser characteristics of a synthetic opal matrix filled with organic dyes are studied upon excitation by nanosecond laser pulses. The appearance of stimulated emission in a partially ordered scattering medium is investigated. It is shown that if the luminescence spectrum of a dye (oxazine-17) is located far outside the photonic bandgap of the opal matrix, stimulated emission along a preferential direction in the (111) plane is observed when pumping exceeds a threshold even without an external optical cavity. The stimulated emission spectrum is considerably narrower than the luminescence spectrum and consists of several narrow lines located within the dye luminescence band. If the luminescence spectrum of a dye (rhodamine 6G) overlaps with the photonic bandgap of the opal matrix, a different picture is observed. The loss of radiation in the matrix leads to the red shift of the luminescence spectrum, while the stimulated emission as in the case of oxazine-17 lies is observed within the luminescence band. (active media, lasers, and amplifiers)

Identifying drought response of semi-arid aeolian systems using near-surface luminescence profiles and changepoint analysis, Nebraska Sandhills.

Science.gov (United States)

Buckland, Catherine; Bailey, Richard; Thomas, David

2017-04-01

Two billion people living in drylands are affected by land degradation. Sediment erosion by wind and water removes fertile soil and destabilises landscapes. Vegetation disturbance is a key driver of dryland erosion caused by both natural and human forcings: drought, fire, land use, grazing pressure. A quantified understanding of vegetation cover sensitivities and resultant surface change to forcing factors is needed if the vegetation and landscape response to future climate change and human pressure are to be better predicted. Using quartz luminescence dating and statistical changepoint analysis (Killick & Eckley, 2014) this study demonstrates the ability to identify step-changes in depositional age of near-surface sediments. Lx/Tx luminescence profiles coupled with statistical analysis show the use of near-surface sediments in providing a high-resolution record of recent system response and aeolian system thresholds. This research determines how the environment has recorded and retained sedimentary evidence of drought response and land use disturbances over the last two hundred years across both individual landforms and the wider Nebraska Sandhills. Identifying surface deposition and comparing with records of climate, fire and land use changes allows us to assess the sensitivity and stability of the surface sediment to a range of forcing factors. Killick, R and Eckley, IA. (2014) "changepoint: An R Package for Changepoint Analysis." Journal of Statistical Software, (58) 1-19.

Splitting of the luminescent excited state of the uranyl ion

International Nuclear Information System (INIS)

Flint, C.D.; Sharma, P.; Tanner, P.A.

1982-01-01

The luminescence spectra of some uranyl compounds has been studied. It has been proposed that the splitting of the luminescent excited state of the uranyl ion is due to a descent in symmetry experienced by the uranyl ion when it is placed in a crystal field. In recent years there has been developed a highly successful model of the electronic structure of the uranyl ion. In this paper the authors use this model to interpret the luminescence spectra of a variety of uranyl compounds

Sensitive luminescent determination of DNA using the terbium(III)-difloxacin complex

International Nuclear Information System (INIS)

Yegorova, Alla V.; Scripinets, Yulia V.; Duerkop, Axel; Karasyov, Alexander A.; Antonovich, Valery P.; Wolfbeis, Otto S.

2007-01-01

The interaction of the terbium-difloxacin complex (Tb-DFX) with DNA has been examined by using UV-vis absorption and luminescence spectroscopy. The Tb-DFX complex shows an up to 85-fold enhancement of luminescence intensity upon titration with DNA. The long decay times allow additional detection schemes like time-resolved measurements in microplate readers to enhance sensitivity by off-gating short-lived background luminescence. Optimal conditions are found at equimolar concentrations of Tb 3+ and DFX (0.1 or 1 μM) at pH 7.4. Under these conditions, the luminescence intensity is linearly dependent on the concentration of ds-DNAs and ss-DNA between 1-1500 ng mL -1 and 4.5-270 ng mL -1 , respectively. The detection limit is 0.5 ng mL -1 for ds-DNAs and 2 ng mL -1 for ss-DNA. The mechanism for the luminescence enhancement was also studied

Unclonable Security Codes Designed from Multicolor Luminescent Lanthanide-Doped Y2O3 Nanorods for Anticounterfeiting.

Science.gov (United States)

Kumar, Pawan; Nagpal, Kanika; Gupta, Bipin Kumar

2017-04-26

The duplicity of important documents has emerged as a serious problem worldwide. Therefore, many efforts have been devoted to developing easy and fast anticounterfeiting techniques with multicolor emission. Herein, we report the synthesis of multicolor luminescent lanthanide-doped Y 2 O 3 nanorods by hydrothermal method and their usability in designing of unclonable security codes for anticounterfeiting applications. The spectroscopic features of nanorods are probed by photoluminescence spectroscopy. The Y 2 O 3 :Eu 3+ , Y 2 O 3 :Tb 3+ , and Y 2 O 3 :Ce 3+ nanorods emit hypersensitive red (at 611 nm), strong green (at 541 nm), and bright blue (at 438 nm) emissions at 254, 305, and 381 nm, respectively. The SEM and TEM/HRTEM results reveal that these nanorods have diameter and length in the range of 80-120 nm and ∼2-5 μm, respectively. The two-dimensional spatially resolved photoluminescence intensity distribution in nanorods is also investigated by using confocal photoluminescence microscopic technique. Further, highly luminescent unclonable security codes are printed by a simple screen printing technique using luminescent ink fabricated from admixing of lanthanide doped multicolor nanorods in PVC medium. The prospective use of these multicolor luminescent nanorods provide a new opportunity for easily printable, highly stable, and unclonable multicolor luminescent security codes for anti-counterfeiting applications.

Monocrystalline silicon photovoltaic luminescent solar concentrator with 4.2% power conversion efficiency

NARCIS (Netherlands)

Desmet, L.; Ras, A.J.M.; Boer, de D.K.G.; Debije, M.G.

2012-01-01

We report conversion efficiencies of experimental single and dual light guide luminescent solar concentrators. We have built several 5¿¿cm×5¿¿cm and 10¿¿cm×10¿¿cm luminescent solar concentrator (LSC) demonstrators consisting of c-Si photovoltaic cells attached to luminescent light guides of Lumogen

Acute toxicity assessment of explosive-contaminated soil extracting solution by luminescent bacteria assays.

Science.gov (United States)

Xu, Wenjie; Jiang, Zhenming; Zhao, Quanlin; Zhang, Zhenzhong; Su, Hongping; Gao, Xuewen; Ye, Zhengfang

2016-11-01

Explosive-contaminated soil is harmful to people's health and the local ecosystem. The acute toxicity of its extracting solution was tested by bacterial luminescence assay using three kinds of luminescent bacteria to characterize the toxicity of the soil. An orthogonal test L 16 (4 5 ) was designed to optimize the soil extracting conditions. The optimum extracting conditions were obtained when the ultrasonic extraction time, ultrasonic extraction temperature, and the extraction repeat times were 6 h, 40 °C, and three, respectively. Fourier transform infrared spectroscopy (FTIR) results showed that the main components of the contaminated soil's extracting solution were 2,4-dinitrotoluene-3-sulfonate (2,4-DNT-3-SO 3 - ); 2,4-dinitrotoluene-5-sulfonate (2,4-DNT-5-SO 3 - ); and 2,6-dinitrotoluene (2,6-DNT). Compared with Photobacterium phosphoreum and Vibrio fischeri, Vibrio qinghaiensis sp. Nov. is more suitable for assessing the soil extracting solution's acute toxicity. Soil washing can remove most of the contaminants toxic to luminescent bacterium Vibrio qinghaiensis sp. Nov., suggesting that it may be a potential effective remediation method for explosive-contaminated soil.

X-ray micro-modulated luminescence tomography (XMLT)

Science.gov (United States)

Cong, Wenxiang; Liu, Fenglin; Wang, Chao; Wang, Ge

2014-01-01

Imaging depth of optical microscopy has been fundamentally limited to millimeter or sub-millimeter due to strong scattering of light in a biological sample. X-ray microscopy can resolve spatial details of few microns deep inside a sample but contrast resolution is inadequate to depict heterogeneous features at cellular or sub-cellular levels. To enhance and enrich biological contrast at large imaging depth, various nanoparticles are introduced and become essential to basic research and molecular medicine. Nanoparticles can be functionalized as imaging probes, similar to fluorescent and bioluminescent proteins. LiGa5O8:Cr3+ nanoparticles were recently synthesized to facilitate luminescence energy storage with x-ray pre-excitation and subsequently stimulated luminescence emission by visible/near-infrared (NIR) light. In this paper, we propose an x-ray micro-modulated luminescence tomography (XMLT, or MLT to be more general) approach to quantify a nanophosphor distribution in a thick biological sample with high resolution. Our numerical simulation studies demonstrate the feasibility of the proposed approach. PMID:24663898

Luminescence properties of isomeric and tautomeric lanthanide pyridinedicarboxylates

International Nuclear Information System (INIS)

Puntus, L.N.; Zolin, V.F.; Babushkina, T.A.; Kutuza, I.B.

2004-01-01

The luminescence and PMR spectra of europium salts of six isomers of 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, and 3,5-pyridinedicarboxylic acids (PDA) had been studied. The distribution of the effective charge in the nearest surroundings of the Eu 3+ ion in these salts was evaluated from Stark splittings of electronic transitions. The values of relative integral intensities of electronic transitions 5 D 0 - 7 F J (J=0-4) in the luminescence spectra were reported. Compounds investigated were divided into three subgroups taking into account the details of the structure of the ligands and details of the luminescence spectra. The ligand coordination manners as well as the strength of interaction between lanthanide ion and ligands were confirmed by data of the PMR and IR spectroscopy

Lanthanide-doped luminescent nanomaterials from fundamentals to bioapplications

CERN Document Server

Chen, Xueyuan; Tu, Datao

2014-01-01

Lanthanide-Doped Luminescent Nanomaterials reviews the latest advances in the development of lanthanide-doped luminescent inorganic nanoparticles for potential bioapplications. This book covers the chemical and physical fundamentals of these nanoparticles, such as the controlled synthesis methodology, surface modification chemistry, optical physics, and their promising applications in diverse bioassays, with an emphasis on heterogeneous and homogeneous in-vitro biodetection of tumor biomarkers. This book is intended for those readers who are interested in systematically understanding the materials design strategy, optical behavior of lanthanide ions, and practical bioapplications of lanthanide nanoparticles. It primarily focuses on the interdisciplinary frontiers in chemistry, physics and biological aspects of luminescent nanomaterials. All chapters were written by scientists active in this field and for a broad audience, providing both beginners and advanced researchers with comprehensive information on the ...

Luminescence from potassium feldspars stimulated by infrared and green light

DEFF Research Database (Denmark)

Duller, G.A.T.; Bøtter-Jensen, L.

1993-01-01

A series of experiments are reported which investigate stimulated luminescence from potassium feldspar. The aim is to provide a basic phenomenological description of the response of the material to stimulation by heat, infrared radiation (875 DELTA 80 nm) and a green light wavelength band from 5 15...... to 560 nm. Two conclusions are drawn: firstly it is suggested that the majority of the trapped charge responsible for the infrared stimulated luminescence signal does not give rise to a thermoluminescence signal, and secondly that a large traction of the two optically stimulated luminescence signals...

High resolution luminescence chronology for Xiashu Loess deposits of Southeastern China

Science.gov (United States)

Yi, Shuangwen; Li, Xusheng; Han, Zhiyong; Lu, Huayu; Liu, Jinfeng; Wu, Jiang

2018-04-01

Loess deposits in Xiashu are representative of such deposits in Southeastern China that are mainly distributed in the middle and lower reaches of the Yangtze River valley. These loess-paleosol sequences provide a key archive of past climate change in humid, subtropical regions. However, the ages of the sequences are not well constrained. In this study, the standard quartz single-aliquot regenerative (SAR) dose optically stimulated luminescence (OSL) and K-feldspar post-infrared infrared stimulated luminescence (post-IR IRSL; pIRIR290) methods are used to date two loess sequences in Nanjing region. Our results show that quartz SAR OSL and K-feldspar pIRIR290 ages are more or less indistinguishable from one another up to ∼50 ka. Beyond this age, the K-feldspar pIRIR ages increased systematically with deposition depth, agreeing well with the expected ages as far as ∼200 ka. On the basis of a fully independently-dated timescale, we are therefore able to propose, for the first time, a new age model for the Xiashu Loess deposits accumulated since the penultimate interglacial period. Using our newly obtained luminescence dating ages, we observe a marked difference between the loess accumulation rates in the two sequences, potentially forced by regional depositional processes and loess preservation.

Integrated light in direct excitation and energy transfer luminescence

OpenAIRE

Chimczak, Eugeniusz

2007-01-01

Integrated light in direct excitation and energy transfer luminescence has been investigated. In the investigations reported here, monomolecular centers were taken into account. It was found that the integrated light is equal to the product of generation rate and time of duration of excitation pulse for both direct excitation and energy transfer luminescence.

Low temperature luminescence and charge carrier trapping in a cryogenic scintillator Li{sub 2}MoO{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Spassky, D.A., E-mail: deris2002@mail.ru [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia); Skobeltsyn Institute of Nuclear Physics, Moscow State University, 119991 Moscow (Russian Federation); Nagirnyi, V. [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia); Savon, A.E. [Skobeltsyn Institute of Nuclear Physics, Moscow State University, 119991 Moscow (Russian Federation); Kamenskikh, I.A. [Physics Faculty, Moscow State University, 119991 Moscow (Russian Federation); Barinova, O.P.; Kirsanova, S.V. [D. Mendeleyev University of Chemical Technology of Russia, 125047 Moscow (Russian Federation); Grigorieva, V.D.; Ivannikova, N.V.; Shlegel, V.N. [Nikolaev Institute of Inorganic Chemistry, SB RAS, 630090 Novosibirsk (Russian Federation); Aleksanyan, E. [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia); A.Alikhanyan National Science Laboratory, 2 Br. Alikhanyan Str., 0036 Yerevan (Armenia); Yelisseyev, A.P. [Sobolev Institute of Geology and Mineralogy, SB RAS, 630090 Novosibirsk (Russian Federation); Belsky, A. [Institute of Light and Matter, CNRS, University Lyon1, 69622 Villeurbanne (France)

2015-10-15

The luminescence and optical properties of promising cryogenic scintillator Li{sub 2}MoO{sub 4} were studied in the temperature region of 2–300 K. The data on luminescence spectra and decay characteristics, excitation spectra, thermostimulated luminescence curves and spectra as well as transmission and reflectivity spectra are presented for the single crystals grown by two different procedures, the conventional Czochralski method and the low-temperature gradient Czochralski technique. The bandgap of Li{sub 2}MoO{sub 4} is estimated from the analysis of transmission, luminescence excitation and reflectivity spectra. Up to three luminescence bands with the maxima at 1.98, 2.08 and 2.25 eV are detected in the emission spectra of crystals and their origin is discussed. In the thermoluminescence curves of both studied crystals, two high-intensity peaks were observed at 22 and 42 K, which are ascribed to the thermal release of self-trapped charge carriers. The coexistence of self-trapped electrons and holes allows one to explain the poor scintillation light yield of Li{sub 2}MoO{sub 4} at low temperatures. - Highlights: • Single crystals of Li{sub 2}MoO{sub 4} were grown by two methods. • The transparency cutoff (~4.3 eV) and bandgap values (<4.9 eV) are estimated. • The emission 2.08 eV is ascribed to self-trapped excitons and quenches at T>7 K. • Shallow traps considerably influence the energy transfer to emission centres. • Co-existence of self-trapped holes and electrons results in a low light yield.

[Method of recording impulses from an implanted cardiostimulator].

Science.gov (United States)

Vetkin, A N; Osipov, V P

1976-01-01

An analysis of pulses from an implanted cardiostimulator recorded from the surface of the patient's body is one of the methods permitting it to pass judgment as to its functioning. Because of the possibility of the recording electrodes location coinciding with the equipotential line an erroneous interpretation of the cardiostimulator's condition is not to be ruled out. It is recommended that the pulses should be recorded with their subsequent analysis in no less than 2 standard ECG leads from the limbs.

The research of characteristic difference of selected frequency luminescence for desert sand

International Nuclear Information System (INIS)

Liu Chao; Wei Mingjian; Li Huhou

2011-01-01

The characters of selected frequency luminescence of four groups of samples from Badain Jaran desert are measured by BG2003 luminescence spectrograph. The measurement subjects include selected frequency optical stimulate luminescence spectrum, selected frequency thermoluminescence spectrum and the dose response curve. A double-peak map is obtained by the result from all groups of data and spectrum. The difference is emerged between each group. The optical stimulate luminescence and thermoluminescence is applied in the measurement process. The dispersion of photon count on every response wavelength is analyzed. Based on the analysis, a better result can be gained by selected frequency thermoluminescence. (authors)

Thermo-luminescent dosimetry

Energy Technology Data Exchange (ETDEWEB)

Reither, M; Schorn, B; Schneider, E

1981-01-01

The development of paediatric radiology which began in the late 195O's has been characterised by the need to limit the dose of ionising radiation to which the child is subjected. The aim has been to keep radiation exposure as low as possible by the introduction of suitable techniques and by the development of new methods. It is therefore surprising that studies in dosimetry in the paediaytric age range have only been carried out in recent years. One reason for this may have been the fact that a suitable technique of measurement was not available at the time. The introduction of solid state dosimetry based on thermo-luminescence, first into radiotherapy (1968) and subsequently into radiodiagnosis, has made it possible to abandon the previously widely used ionisation chamber. The purpose of the present paper is to indicate the suitability of this form of dose measurement for paediatric radiological purposes and to stimulate its application in this field.

Thermal quenching of luminescence processes in feldspars

DEFF Research Database (Denmark)

Poolton, N.R.J.; Bøtter-Jensen, L.; Duller, G.A.T.

1995-01-01

, which display very different behaviour. The first involves the internal transitions of common transition metal ions. The second is typical of centres not displaying excited states within the band gap that are likely to arise from direct recombination between the conduction band and the ground state......The technique of optically stimulated luminescence has important uses in the dose evaluation of irradiated feldspars. The luminescence process involves the eviction of electrons from donor traps, charge transfer through the conduction band, and recombination at acceptor sites; each...

Determination of organophosphorus pesticides in water samples by using a new sensitive luminescent probe of Eu (III) complex

Energy Technology Data Exchange (ETDEWEB)

Azab, Hassan A., E-mail: azab2@yahoo.com; Anwar, Z.M.; Rizk, M.A.; Khairy, Gasser M.; El-Asfoury, M.H.

2015-01-15

This work describes the application of fluorescence for investigating the interactions of Eu(III)-TAN-1,10 phenanthroline (where TAN=4,4,4-Trifluoro-1-(2-naphthyl)-1,3-butanedione) with pesticides Chlorpyrifos, Malathion, Endosulfan, Heptachlor. The complex was synthesized and characterized by elemental analysis, FTIR, x-ray spectroscopy, solid fluorescence and thermal analysis. The results indicated that the composition of this complex is [Eu(TAN){sub 2}(Phen)(H{sub 2}O){sub 2}]Cl. The luminescence properties of the complex in different solvents and at different pH values have been investigated. The results show that the complex exhibits more efficient luminescence at pH=7.5. The interactions of Eu-complex with different pesticides (Chlorpyrifos, Malathion, Endosulfan, and Heptachlor) in aqueous medium have been investigated by fluorescence measurements. The luminescence intensity of the probe is quenched by Malathion and enhanced by (Endosulfan, Heptachlor, and Chlorpyrifos). Direct methods for the determination of the pesticides under investigation have been developed using the luminescence variations of the probe in solution. The detection limits are 0.47, 1.02, 0.66, 0.64 µmol/L for Chlorpyrifos, Endosulfan, Heptachlor, and Malathion, respectively. The binding constants and thermodynamic parameters of the pesticides with probe were evaluated. The emission quantum yield (QY=0.71) of Eu(III)-complex was determined using tris (2,2'-bipyridyl) dichlororuthenium(II) hexahydrate. A thermodynamic analysis showed that the reaction is spontaneous with negative ΔG. Effect of some relevant interferents on the detection of pesticides has been investigated. The new method was applied to the determination of the pesticides in different types of water samples (tap, river, and waste water). - Highlights: • A new luminescent probe of Eu (III) complex has been developed for sensing some organophosphorus pesticides. • Four guest pesticides Chlorpyrifos, Malathion

Determination of organophosphorus pesticides in water samples by using a new sensitive luminescent probe of Eu (III) complex

International Nuclear Information System (INIS)

Azab, Hassan A.; Anwar, Z.M.; Rizk, M.A.; Khairy, Gasser M.; El-Asfoury, M.H.

2015-01-01

This work describes the application of fluorescence for investigating the interactions of Eu(III)-TAN-1,10 phenanthroline (where TAN=4,4,4-Trifluoro-1-(2-naphthyl)-1,3-butanedione) with pesticides Chlorpyrifos, Malathion, Endosulfan, Heptachlor. The complex was synthesized and characterized by elemental analysis, FTIR, x-ray spectroscopy, solid fluorescence and thermal analysis. The results indicated that the composition of this complex is [Eu(TAN) 2 (Phen)(H 2 O) 2 ]Cl. The luminescence properties of the complex in different solvents and at different pH values have been investigated. The results show that the complex exhibits more efficient luminescence at pH=7.5. The interactions of Eu-complex with different pesticides (Chlorpyrifos, Malathion, Endosulfan, and Heptachlor) in aqueous medium have been investigated by fluorescence measurements. The luminescence intensity of the probe is quenched by Malathion and enhanced by (Endosulfan, Heptachlor, and Chlorpyrifos). Direct methods for the determination of the pesticides under investigation have been developed using the luminescence variations of the probe in solution. The detection limits are 0.47, 1.02, 0.66, 0.64 µmol/L for Chlorpyrifos, Endosulfan, Heptachlor, and Malathion, respectively. The binding constants and thermodynamic parameters of the pesticides with probe were evaluated. The emission quantum yield (QY=0.71) of Eu(III)-complex was determined using tris (2,2'-bipyridyl) dichlororuthenium(II) hexahydrate. A thermodynamic analysis showed that the reaction is spontaneous with negative ΔG. Effect of some relevant interferents on the detection of pesticides has been investigated. The new method was applied to the determination of the pesticides in different types of water samples (tap, river, and waste water). - Highlights: • A new luminescent probe of Eu (III) complex has been developed for sensing some organophosphorus pesticides. • Four guest pesticides Chlorpyrifos, Malathion, Endosulfan, and

A luminescence lifetime assisted ratiometric fluorimeter for biological applications

Science.gov (United States)

Lam, Hung; Kostov, Yordan; Rao, Govind; Tolosa, Leah

2009-12-01

In general, the most difficult task in developing devices for fluorescence ratiometric sensing is the isolation of signals from overlapping emission wavelengths. Wavelength discrimination can be achieved by using monochromators or bandpass filters, which often lead to decreased signal intensities. The result is a device that is both complex and expensive. Here we present an alternative system—a low-cost standalone optical fluorimeter based on luminescence lifetime assisted ratiometric sensing (LARS). This paper describes the principle of this technique and the overall design of the sensor device. The most significant innovation of LARS is the ability to discriminate between two overlapping luminescence signals based on differences in their luminescence decay rates. Thus, minimal filtering is required and the two signals can be isolated despite significant overlap of luminescence spectra. The result is a device that is both simple and inexpensive. The electronic circuit employs the lock-in amplification technique for the signal processing and the system is controlled by an onboard microcontroller. In addition, the system is designed to communicate with external devices via Bluetooth.

LUMINESCENT PROPERTIES OF SILICATE GLASSES WITH CERIUM IONS AND ANTIMONY

Directory of Open Access Journals (Sweden)

A. M. Klykova

2014-05-01

Full Text Available The paper deals with the results of an experimental study of luminescence excitation spectra and luminescence of silicate glasses containing cerium ions and antimony. The aim of this work was to study the features of the luminescence and the effect of UV irradiation and heat treatment on luminescence and the state of cerium ions and antimony in glass. We investigated glass system Na2O-ZnO-Al2O3-SiO2-NaF-NaBr with additives CeO2 and Sb2O3. Synthesis was carried out in platinum crucibles in the air at 14500C. The samples were polished glass plates with a thickness of 0.5-1 mm. UV irradiation was carried out with a mercury lamp having a wide range of radiation in the spectral range 240-390 nm. It was conducted in a Nabertherm muffle furnaces. Luminescence spectra and excitation spectra were measured using a spectrofluorimeter MPF-44A (PerkinElmer at the room temperature. Measured luminescence spectra were corrected in view of the spectral sensitivity of the photodetector for spectrofluorimeter. Adjustment of the excitation spectra for the spectral dependence of the intensity of the excitation source was not carried out. During the experiments it was found that in silicate glasses Sb3+ ions can exist in two energy states, which corresponds to a different environment with oxygen ions. Heat treatment of these glasses in an oxidizing atmosphere leads to an increase in ion concentration of Sb3+ ions with a greater amount of oxygen in the environment. In glasses containing antimony and cerium ions, ultraviolet irradiation causes a change in the valence of cerium ions and antimony, which is accompanied by luminescence quenching. Subsequent heat treatment of glass leads to the inverse processes and restore luminescence excitation spectra. The study of fluorescent properties of silicate glasses with cerium and antimony ions led to the conclusion of the practical significance of this work. Promising multifunctional materials can be created on the basis of

Nanoscale luminescent lanthanide-based metal–organic frameworks: properties, synthesis, and applications

Energy Technology Data Exchange (ETDEWEB)

Hu, Dongqin; Song, Yonghai; Wang, Li, E-mail: lwanggroup@aliyun.com [Jiangxi Normal University, Key Laboratory of Functional Small Organic Molecule, Ministry of Education, Key Laboratory of Chemical Biology, Jiangxi Province, College of Chemistry and Chemical Engineering (China)

2015-07-15

Nanoscale luminescent lanthanide-based metal–organic frameworks (NLLn-MOFs) possess superior optical and physical properties such as higher luminescent lifetime, quantum yield, high stability, high surface area, high agent loading, and intrinsic biodegradability, and therefore are regarded as a novel generation of luminescent material compared with bulk lanthanide-based metal–organic frameworks (Ln-MOFs). Traditional luminescent Ln-MOFs have been well studied; however, NLLn-MOFs taking the advantages of nanomaterials have attracted extensive investigations for applications in optical imaging in living cells, light-harvesting, and sensing. In this review, we provide a survey of the latest progresses made in developing NLLn-MOFs, which contains the fundamental optical features, synthesis, and their potential applications. Finally, the future prospects and challenges of the rapidly growing field are summarized.

Intrinsic and defect related luminescence in double oxide films of Al–Hf–O system under soft X-ray and VUV excitation

Energy Technology Data Exchange (ETDEWEB)

Pustovarov, V.A., E-mail: vpustovarov@bk.ru [Ural Federal University, 19 Mira Street, 620002 Yekaterinburg (Russian Federation); Smirnova, T.P.; Lebedev, M.S. [Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Science, Novosibirsk 630090 (Russian Federation); Gritsenko, V.A. [Institute of Semiconductor Physics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090 (Russian Federation); Novosibirsk National Research University, 2 Pirogova Street, 630090 Novosibirsk (Russian Federation); Kirm, M. [Institute of Physics, University of Tartu, 14c Ravila, 50411 Tartu (Estonia)

2016-02-15

Low temperature time-resolved luminescence spectra in the region of 2.5–9.5 eV under soft X-ray excitation as well as time-resolved luminescence excitation spectra in the UV–VUV region (3.7–12 eV) of solid solutions Al{sub x}Hf{sub y}O{sub 1−x−y} thin films were investigated. The values of x and Al/Hf ratio were determined from X-ray photoelectron srectroscopy data. Hafnia films and films mixed with alumina were grown in a flow-type chemical vapor deposition reactor with argon as a carrier gas. In addition, pure alumina films were prepared by the atomic layer deposition method. A strong emission band with the peak position at 4.4 eV and with the decay time in the μs-range was revealed for pure hafnia films. The emission peak at 7.74 eV with short nanosecond decay kinetics was observed in the luminescence spectra for pure alumina films. These emission bands were ascribed to the radiative decay of self-trapped excitons (an intrinsic luminescence) in pure HfO{sub 2} and Al{sub 2}O{sub 3} films, respectively. Along with intrinsic host emission, defect related luminescence bands with a larger Stokes shift were observed. In the emission spectra of the solid solution films (x=4; 17; 20 at%) the intrinsic emission bands are quenched and only the luminescence of defects (an anion vacancies) was observed. Based on transformation of the luminescence spectra and ns-luminescence decay kinetics, as well as changes in the time-resolved luminescence and luminescence excitation spectra, the relaxation processes in the films of solid solution are discussed. - Highlights: • Low temperature time−resolved PL spectra were studied in a broad range (1.5−9.5 eV). • We carried out a luminescent control of point defects (anion vacancies) and self−trapped excitons. • We observed photoluminescence of excitons bound on defects. • We observed changes of photoluminescence properties with varying ratio components.

Determination of piroxicam in pharmaceutical formulations and urine samples using europium-sensitized luminescence

Energy Technology Data Exchange (ETDEWEB)

Al-Kindy, Salma M.Z. [Department of Chemistry, College of Science, P.O. Box 36, Al-Khod 123, Sultan Qaboos University (Oman)], E-mail: alkindy@squ.edu.om; Suliman, Fakhr Eldin O.; Al-Wishahi, Aisha A.; Al-Lawati, Haidar A.J.; Aoudia, Muhammed [Department of Chemistry, College of Science, P.O. Box 36, Al-Khod 123, Sultan Qaboos University (Oman)

2007-12-15

A simple, selective and sensitive luminescence method for the assay of piroxicam (PX) in aqueous solution is developed. The method is based on the luminescence sensitization of europium (Eu{sup 3+}) by formation of ternary complex with PX in the presence of TOPO and Tween-80 as surfactant. The signal for Eu-PX-TOPO is monitored at {lambda}{sub ex}=359 nm and {lambda}{sub em}=615 nm. Optimum conditions for the formation of the complex in sequential injection analysis (SIA) were 0.01 M Tris buffer, pH 7.5, TOPO 5.0x10{sup -5} M, Tween-80 0.15% and 1.5 mM of Eu{sup 3+}, which allows the determination of 100-1000 ppb of PX with limit of detection (LOD) of 29 ppb. The relative standard deviations of the method range between 0.5% and 3.9% indicating excellent reproducibility of the method. The proposed method was successfully applied for the assay of PX in pharmaceutical formulations and in urine samples. Average recoveries of 100.8{+-}1.7% was obtained in tablet, whereas a recovery of 97.5{+-}2.0% was obtained for the total PX (PX+hydoxy-PX) in urine sample.

Determination of piroxicam in pharmaceutical formulations and urine samples using europium-sensitized luminescence

International Nuclear Information System (INIS)

Al-Kindy, Salma M.Z.; Suliman, Fakhr Eldin O.; Al-Wishahi, Aisha A.; Al-Lawati, Haidar A.J.; Aoudia, Muhammed

2007-01-01

A simple, selective and sensitive luminescence method for the assay of piroxicam (PX) in aqueous solution is developed. The method is based on the luminescence sensitization of europium (Eu 3+ ) by formation of ternary complex with PX in the presence of TOPO and Tween-80 as surfactant. The signal for Eu-PX-TOPO is monitored at λ ex =359 nm and λ em =615 nm. Optimum conditions for the formation of the complex in sequential injection analysis (SIA) were 0.01 M Tris buffer, pH 7.5, TOPO 5.0x10 -5 M, Tween-80 0.15% and 1.5 mM of Eu 3+ , which allows the determination of 100-1000 ppb of PX with limit of detection (LOD) of 29 ppb. The relative standard deviations of the method range between 0.5% and 3.9% indicating excellent reproducibility of the method. The proposed method was successfully applied for the assay of PX in pharmaceutical formulations and in urine samples. Average recoveries of 100.8±1.7% was obtained in tablet, whereas a recovery of 97.5±2.0% was obtained for the total PX (PX+hydoxy-PX) in urine sample

Characterization and luminescent properties of thermally annealed olivines

International Nuclear Information System (INIS)

Colin-Garcia, Maria; Correcher, Virgilio; Garcia-Guinea, Javier; Heredia-Barbero, Alejandro; Roman-Lopez, Jesus; Ortega-Gutierrez, Fernando; Negron-Mendoza, Alicia; Ramos-Bernal, Sergio

2013-01-01

Olivine is an iron-magnesium solid solution silicate (Mg,Fe) 2 SiO 4 and it is probably one of the most abundant mineral phase in the Solar System, it is present in the primitive carbonaceous meteorites (i.e Allende), and in ordinary chondritic meteorite, comets or terrestrial planets. The olivine grains in those bodies have been exposed to different radiation sources like UV, electrons, cosmic radiation, etc. Here, we explore the effect of ionizing and non ionizing radiation on the luminescence emission of the two well-characterised olivine samples from Mexico and Spain by means of cathodoluminescence and thermoluminescence. The analyses by X-ray dispersive energies in the scanning electron microscopy show differences between the samples in the amount of iron and magnesium and also show traces of rare elements. Olivine exhibits spectral cathodoluminescence emissions of low intensity, explained for the quenching of the luminescence of the iron, and sharp signals assigned as impurities. Cathodoluminescence and thermoluminescence glow curves of the natural, and UV induced olivine samples were obtained. Our results show that thermal treatments at 1100 °C change the mineral molecular structure and the luminescence properties of this mineral phase. These results confirm an active participation of physical factors influencing the luminescent properties of olivine. -- Highlights: ► Luminescent properties of two olivines samples (Mexican and Spanish) were explored. ► EDS show different iron and magnesium content and traces of rare elements on both. ► Olivine exhibits spectral CL emissions of low intensity due to the quenching of iron. ► Treatments at 1100 °C change the mineral structure and its response to UV radiation

Real-time luminescence from Al2O3 fiber dosimeters

International Nuclear Information System (INIS)

Polf, J.C.; Yukihara, E.G.; Akselrod, M.S.; McKeever, S.W.S.

2004-01-01

The real-time luminescence signal from Al 2 O 3 single crystal fibers, monitored during simultaneous irradiation and optical stimulation, was investigated using computer simulations and experimental measurements. Both radioluminescence (RL) and optically stimulated luminescence (OSL) signals were studied. The simulations were performed initially using a simple one-trap/one-recombination-center energy band model, and then extended to include shallow and deep electron traps as well. Real-time luminescence experiments were performed for different radiation dose rates and optical stimulation powers using periodic laser stimulation of the samples through a fiber optic cable, and the experimental results were compared with the predictions from the computer simulations. The luminescence signal was observed, both theoretically and experimentally, to increase from its initial value to a steady-state level. The steady-state RL and OSL levels were found to be dependent on dose rate, the steady-state level of the real-time OSL being independent of laser power. It was also shown that the total integrated absorbed dose throughout the irradiation period can be determined by correcting the real-time OSL signal for depletion caused by each laser stimulation pulse. The effects of the shallow and deep traps on the time-dependence of the real-time luminescence signal were studied comparing the experimental data from several Al 2 O 3 fibers known to have different trapping state concentrations. The additional traps were found to slow the response of the real-time luminescence such that the time to reach steady state was increased as the additional traps were added

Synthesis and luminescent properties of PEO/lanthanide oxide nanoparticle hybrid films

International Nuclear Information System (INIS)

Goubard, F.; Vidal, F.; Bazzi, R.; Tillement, O.; Chevrot, C.; Teyssie, D.

2007-01-01

In this study, we investigate the optical properties of lanthanide oxide nanoparticles dispersed in poly(ethylene oxide) (PEO) network as thermally stable polymeric films. The aim of this work is both to keep a good optical transparency in the visible domain and to obtain luminescent materials after incorporation of nanoparticles. For this purpose, we develop luminescent nanocrystals of oxides containing terbium ion as a doping element in Gd 2 O 3 . These sub-5-nm lanthanide oxides nanoparticles have been prepared by direct oxide precipitation in high-boiling polyalcohol solutions and characterized by luminescence spectroscopy. PEO/lanthanide oxide nanohybrid films are prepared by radical polymerization of poly(ethylene glycol) methacrylate after introduction of lanthanide oxide particles. As a first result; the obtained films present interesting luminescence properties with a very low lanthanide oxide content (up to 0.29 wt%). Furthermore, these films are still transparent and keep their original mechanical properties. Prior to describe the specific applications to optical use, we report here the dynamic mechanical analysis (DMA), X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), and luminescent properties of. nanohybrid films

Scintillation and optical stimulated luminescence of Ce-doped CaF2

International Nuclear Information System (INIS)

Yanagida, Takayuki; Fujimoto, Yutaka; Watanabe, Kenichi; Fukuda, Kentaro; Kawaguchi, Noriaki; Miyamoto, Yuka; Nanto, Hidehito

2014-01-01

Scintillation and optical stimulated luminescence of Ce 0.1–20% doped CaF 2 crystals prepared by Tokuyama Corp. were investigated. In X-ray induced scintillation spectra, luminescence due to Ce 3+ 5d–4f transition appeared around 320 nm with typically 40 ns decay time. By 241 Am 5.5 MeV α-ray irradiation, 0.1% doped one showed the highest scintillation light yield and the light yield monotonically decreased with Ce concentrations. Optically stimulated luminescence after X-ray irradiation was observed around 320 nm under 550 or 830 nm stimulation in all samples. As a result, intensities of optically stimulated luminescence were proportional to Ce concentrations. Consequently, scintillation and optically stimulated luminescence resulted to have a complementary relation in Ce-doped CaF 2 system. - Highlights: • Optical, scintillation, and OSL properties of Ce 0.1–20% doped CaF 2 were studied. • Scintillation light yield exhibited inverse proportionality to Ce concentrations. • OSL intensities showed proportionality to Ce concentrations. • Complementary relation of scintillation and OSL was experimentally confirmed

Highly sensitive sorption-luminescence determination of trace europium with preconcentration on silica chemically modified with iminodiacetic acid

International Nuclear Information System (INIS)

Voronina, R.D.; Zorov, N.B.

2007-01-01

Features of a sorption-luminescence method for the determination of trace europium were studied. The method includes the preliminary sorption of europium at pH 7.1 from solutions with silica chemically modified with iminodiacetic acid, the subsequent treatment of the sorbent with 2-thenoyltrifluoroacetone at pH 8.0, and the measurement of the intensity of luminescence of the surface three-component europium complex at 613 nm. The effect of moisture as the quencher of luminescence of the surface europium complex was studied, and techniques for its removal were proposed. Sorption in the static mode provides the detection limit of europium of 7 x 10 -5 g/ml. The calibration plot is linear in the range of two orders of magnitude of europium concentration in solutions. The relative standard deviation in the determination of 1.5 x 10 -2 μg/ml europium is 5%. In the dynamic mode of sorption from 1000 ml of an analyzed solution with the use of sorption-desorption, the detection limit of europium of 8 x 10 -7 μg/ml was attained [ru

Assessment of terbium (III) as a luminescent probe for the detection of tuberculosis biomarkers

International Nuclear Information System (INIS)

Bamogo, W.; Mugherli, L.; Banyasz, A.; Novelli-Rousseau, A.; Mallard, F.; Tran-Thi, T.-H.

2015-01-01

A detection method for nicotinic acid, a specific metabolite marker of Mycobacterium tuberculosis present in cultures and patients' breath, is studied in complex solutions containing other metabolites and in biological media such as urine, saliva and breath condensate. The method is based on the analysis of the luminescence increase of Tb 3+ complexes in the presence of nicotinic acid due to the energy transfer from the excited ligand to the lanthanide ion. It is shown that other potential markers found in M. tuberculosis culture supernatant, such as methyl phenylacetate, p-methyl anisate, methyl nicotinate and 2-methoxy biphenyl, can interfere with nicotinic acid via a competitive absorption of the excitation photons. A new strategy to circumvent these interferences is proposed with an upstream trapping of volatile markers preceding the detection of nicotinic acid in the liquid phase via the luminescence of Tb 3+ complexes. The cost of the method is evaluated and compared with the Xpert MTB/RIF test endorsed by the World Health Organization. - Highlights: • Nicotinic acid, a specific marker of M. tuberculosis, can be detected via luminescence. • The detection limit with a commercial phosphorimeter is 0.4 µmol·L -1 . • Other metabolites of M. tuberculosis can interfere via absorbed excitation light. • The interference can be removed via trapping of the most volatile metabolites. • A breath analysis procedure's cost is compared with the Xpert TBM/RIF test.

Assessment of terbium (III) as a luminescent probe for the detection of tuberculosis biomarkers

Energy Technology Data Exchange (ETDEWEB)

Bamogo, W. [CNRS, IRAMIS, UMR 3685 NIMBE/LEDNA, F-91191 Gif-sur-Yvette (France); Mugherli, L. [CEA, IRAMIS, UMR 3685 NIMBE/LEDNA, F-91191 Gif-sur-Yvette (France); Banyasz, A. [CNRS, IRAMIS, LIDyL/Laboratoire Francis Perrin, URA 2453, F-91191 Gif-sur-Yvette (France); Novelli-Rousseau, A.; Mallard, F. [BioMérieux SA, F-38000 Grenoble (France); Tran-Thi, T.-H., E-mail: thu-hoa.tran-thi@cea.fr [CNRS, IRAMIS, UMR 3685 NIMBE/LEDNA, F-91191 Gif-sur-Yvette (France)

2015-10-08

A detection method for nicotinic acid, a specific metabolite marker of Mycobacterium tuberculosis present in cultures and patients' breath, is studied in complex solutions containing other metabolites and in biological media such as urine, saliva and breath condensate. The method is based on the analysis of the luminescence increase of Tb{sup 3+} complexes in the presence of nicotinic acid due to the energy transfer from the excited ligand to the lanthanide ion. It is shown that other potential markers found in M. tuberculosis culture supernatant, such as methyl phenylacetate, p-methyl anisate, methyl nicotinate and 2-methoxy biphenyl, can interfere with nicotinic acid via a competitive absorption of the excitation photons. A new strategy to circumvent these interferences is proposed with an upstream trapping of volatile markers preceding the detection of nicotinic acid in the liquid phase via the luminescence of Tb{sup 3+} complexes. The cost of the method is evaluated and compared with the Xpert MTB/RIF test endorsed by the World Health Organization. - Highlights: • Nicotinic acid, a specific marker of M. tuberculosis, can be detected via luminescence. • The detection limit with a commercial phosphorimeter is 0.4 µmol·L{sup -1}. • Other metabolites of M. tuberculosis can interfere via absorbed excitation light. • The interference can be removed via trapping of the most volatile metabolites. • A breath analysis procedure's cost is compared with the Xpert TBM/RIF test.

Structural and luminescence effects of Ga co-doping on Ce-doped yttrium aluminate based phosphors

Energy Technology Data Exchange (ETDEWEB)

Ayvacikli, M. [Celal Bayar University, Faculty of Arts and Sciences, Department of Physics, Muradiye, Manisa (Turkey); Canimoglu, A. [Nigde University, Faculty of Arts and Sciences, Physics Department, Nigde (Turkey); Muresan, L.E., E-mail: laura_muresan2003@yahoo.com [Babes Bolyai University, Raluca Ripan Institute for Research in Chemistry, Fantanele 30, 400294 Cluj-Napoca (Romania); Barbu Tudoran, L. [Babes Bolyai University, Electronic Microscopy Centre, Clinicilor 37, 400006 Cluj Napoca (Romania); Garcia Guinea, J. [Museo Nacional Ciencias Naturales, Jose Gutierrez Abascal 2, Madrid 28006 (Spain); Karabulut, Y. [Celal Bayar University, Faculty of Arts and Sciences, Department of Physics, Muradiye, Manisa (Turkey); Jorge, A. [Museo Nacional Ciencias Naturales, Jose Gutierrez Abascal 2, Madrid 28006 (Spain); Karali, T. [Ege University, Institute of Nuclear Sciences, 35100 Bornova, İzmir (Turkey); Can, N., E-mail: cannurdogan@yahoo.com [Celal Bayar University, Faculty of Arts and Sciences, Department of Physics, Muradiye, Manisa (Turkey); Jazan University, Physics Department, P.O. Box 114, 45142 Jazan (Saudi Arabia)

2016-05-05

Herein, we primarily focus on luminescence spectrum measurements of various types of green emitting yttrium aluminate phosphors modified with gallium (Y{sub 3}Al{sub 5-x}Ga{sub x}O{sub 12}) 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{sub Al} antisite defects. The broad emission band of garnet phosphors is shifted from 526 nm to 498 nm with increasing of Ga{sup 3+} 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 °C occur in aluminate host garnets. - Highlights: • We present preparation of YAG:Ce{sup 3+}, Ga{sup 3+} phosphors by a solid state reaction method. • The shape and size of phosphor particles were investigated. • The luminescence properties were studied by different excitation sources.

A study of luminescence and absorption spectra of GaP

International Nuclear Information System (INIS)

Mansour, H.M.M.; Abdel Wahab, S.M.

1994-08-01

Experimental luminescence and absorption spectra of GaP at room temperature are presented. A theoretical analysis has been performed on the luminescence and absorption spectra in GaP. The experimental data are in good agreement with the theoretical results. (author). 18 refs, 8 figs

Study on the light-color mixing of rare earth luminescent materials for anti-counterfeiting application

Science.gov (United States)

Zhang, Jishu; Zhang, Yingzi; Tao, Jin; Zhu, Yanan

2018-04-01

In order to find out the light color mixing mechanism of rare earth luminescent materials used in anti-counterfeiting fibers, we prepared three kinds of rare earth luminescent materials according to RGB tri-primary color, and mixed it together to form different mixtures in certain proportion. The phase structures of the luminescent material monomers were measured by x-ray diffractometer. The photochromic properties of the luminescent materials were tested and analyzed by fluorescence spectrophotometer. The results show that the light color mixing was consistent with the blending principle of additive color, but not the same because of the photochromic properties of rare earth luminescent materials, and we explored the reasons in the light wavelength and intensity. It was found that the enhancement of the luminescence intensity of the mixture on account of the superimposing of luminescence.

Study of the luminescence properties of a natural amazonite

Energy Technology Data Exchange (ETDEWEB)

Correcher, V., E-mail: v.correcher@ciemat.es [CIEMAT, Av. Complutense 22, Madrid 28040 (Spain); Garcia-Guinea, J. [Museo Nacional de Ciencias Naturales, CSIC, C/Jose Gutierrez Abascal 2, Madrid 28006 (Spain)

2011-09-15

Most gemstones, being natural materials (silicates, carbonates, phosphates, etc.), exhibit luminescence emission. This property could be potentially employed for personal dosimetry in the case of radiation accident or radiological terrorism where conventional monitoring has not been established. We, herein, report on the thermoluminescence (TL), radioluminescence (RL) and infra-red stimulated luminescence (IRSL) response of a well-characterised natural amazonite (KAlSi{sub 3}O{sub 8}) that, due to its bright blue-green colour when polished, is used as a gemstone. The luminescence emission wavelengths, intensities and thermal kinetics of the amazonite luminescence curves reveal that the ultraviolet band measured on amazonite aliquots is similar to other common K-rich feldspars. On this basis, one can conclude (i) association between twinning and the UV-blue TL emission can be related to structural defects located in the twin-domain boundaries where ionic alkali-self-diffusion, irreversible water losses and irreversible dehydroxylation processes can be involved. (ii) Amazonite exhibits a complex structure with several planar defects (twinning and exsolution interphases which can hold hydroxyl groups, water molecules, etc.) and point defects (impurities, Na, Pb, Mn, etc.) that can act as luminescence centres, and in fact, green and red emissions are respectively associated with the presence of Mn and Fe impurities. Finally, (iv) the thermal stability tests performed on the TL emission of the amazonite confirm a continuum in the trap distribution, i.e. progressive changes in the glow curve shape, intensity and temperature position of the maximum peak.

The recombination channels of luminescence excitation in YAG:Yb single crystalline films

International Nuclear Information System (INIS)

Zakharko, Ya.M.; Luchechko, A.P.; Ubizskii, S.B.; Syvorotka, I.I.; Martynyuk, N.V.; Syvorotka, I.M.

2007-01-01

Absorption and emission spectra, luminescence decay kinetics and thermostimulated luminescence of X-ray irradiated YAG:Yb single crystalline films were studied. Two emission bands peaked at 420 and 488 nm have been detected in the investigated films. The strong thermal quenching of luminescence band at 488 nm was observed above 160 K. The influence of growth conditions and annealing in air on the lifetime of Yb 3+ ion excited state in the IR spectral region have been revealed. The recombination mechanisms of the f-f transition at Yb 3+ ion excitation, as well as the mechanism of lifetime shortening for the excited Yb 3+ luminescence have been discussed

Excitation-resolved cone-beam x-ray luminescence tomography.

Science.gov (United States)

Liu, Xin; Liao, Qimei; Wang, Hongkai; Yan, Zhuangzhi

2015-07-01

Cone-beam x-ray luminescence computed tomography (CB-XLCT), as an emerging imaging technique, plays an important role in in vivo small animal imaging studies. However, CB-XLCT suffers from low-spatial resolution due to the ill-posed nature of reconstruction. We improve the imaging performance of CB-XLCT by using a multiband excitation-resolved imaging scheme combined with principal component analysis. To evaluate the performance of the proposed method, the physical phantom experiment is performed with a custom-made XLCT/XCT imaging system. The experimental results validate the feasibility of the method, where two adjacent nanophosphors (with an edge-to-edge distance of 2.4 mm) can be located.

Size-dependent abnormal thermo-enhanced luminescence of ytterbium-doped nanoparticles.

Science.gov (United States)

Cui, Xiangshui; Cheng, Yao; Lin, Hang; Huang, Feng; Wu, Qingping; Wang, Yuansheng

2017-09-21

Thermal quenching above 300 K is widely expected in photoluminescence. Luminescence quenching is usually ascribed to the non-radiative relaxation of excited electrons to the ground state of the activators, during which a high temperature always plays a role in pushing the excited electrons towards the quenching channels, leading to thermal quenching. For the lanthanide-doped nanoparticles, however, there is a special luminescence quenching channel that does not exist in their bulk counterparts, i.e., energy migration-induced surface quenching. Herein, a size-dependent abnormal thermal enhancement of luminescence in the temperature range of 300 K to 423 K in the ytterbium-doped fluoride nanoparticles is presented for the first time. Importantly, in this work, we originally demonstrate that the energy migration-induced surface quenching can be suppressed by increasing temperature, which results in the abnormal thermal enhancement of luminescence. According to the temperature-dependent X-ray diffraction and lifetime analyses, an underlying mechanism based on the effect of thermal lattice expansion on ytterbium-mediated energy migration is proposed. This new finding adds new insights to the size effect on the luminescent characteristics of nanoparticles, which could be utilized to construct some unique nanostructures, especially for many important temperature-related purposes, such as thermal sensing technology.

Defect-induced luminescence in sol-gel silica samples doped with Co(II) at different concentrations

Energy Technology Data Exchange (ETDEWEB)

Jimenez-Sandoval, S. [Centro de Investigacion y Estudios Avanzados, Queretaro, Apdo. Postal 1-798, Queretaro, Qro. 76001 (Mexico); Estevez, M. [Fisica Aplicada y Tecnologia Avanzada, UNAM, Apdo. Postal 1-1010, Queretaro, Qro. 76000 (Mexico); Pacheco, S. [Instituto Mexicano del Petroleo, Av. 100 metros (Mexico); Vargas, S. [Fisica Aplicada y Tecnologia Avanzada, UNAM, Apdo. Postal 1-1010, Queretaro, Qro. 76000 (Mexico); Rodriguez, R. [Fisica Aplicada y Tecnologia Avanzada, UNAM, Apdo. Postal 1-1010, Queretaro, Qro. 76000 (Mexico)], E-mail: rogelior@servidor.unam.mx

2007-12-20

The defect-induced luminescence properties of silica samples prepared by the sol-gel method and doped with Co(II) are reported. Silica monoliths doped with different concentrations of Co(II) were laser irradiated (He-Ne 632.8 nm) producing fluorescence. However, this fluorescence is exponentially reduced with the irradiation time, to practically disappear. The rate the fluorescence decays can be well modeled with a double exponential function of the irradiation time, containing two different relaxation times; a baseline is also required to take into account some residual fluorescence. The characteristic times involved in this luminescence quenching process are in the range of seconds. This luminescence suppression can be associated to the local heating produced by the laser irradiation when focused in a small area (2 {mu}m in diameter) on the sample. This heating process reduces physical (grain boundaries, surface states) and chemical (oxygen vacancies produced by the dopant) defects in the sample.

Short-wavelength magnetic recording new methods and analyses

CERN Document Server

Ruigrok, JJM

2013-01-01

Short-wavelength magnetic recording presents a series of practical solutions to a wide range of problems in the field of magnetic recording. It features many new and original results, all derived from fundamental principles as a result of up-to-date research.A special section is devoted to the playback process, including the calculations of head efficiency and head impedance, derived from new theorems.Features include:A simple and fast method for measuring efficiency; a simple method for the accurate separation of the read and write behaviour of magnetic heads; a new concept - the bandpass hea

Iron control of the Vibrio fischeri luminescence system in Escherichia coli.

Science.gov (United States)

Dunlap, P V

1992-01-01

Iron influences luminescence in Vibrio fischeri; cultures iron-restricted for growth rate induce luminescence at a lower optical density (OD) than faster growing, iron-replete cultures. An iron restriction effect analogous to that in V. fischeri (slower growth, induction of luminescence at a lower OD) was established using Escherichia coli tonB and tonB+ strains transformed with recombinant plasmids containing the V. fischeri lux genes (luxR luxICDABEG) and grown in the presence and absence of the iron chelator ethylenediamine-di(o-hydroxylphenyl acetic acid) (EDDHA). This permitted the mechanism of iron control of luminescence to be examined. A fur mutant and its parent strain containing the intact lux genes exhibited no difference in the OD at induction of luminescence. Therefore, an iron-binding repressor protein apparently is not involved in iron control of luminescence. Furthermore, in the tonB and in tonB+ strains containing lux plasmids with Mu dI(lacZ) fusions in luxR, levels of beta-galactosidase activity (expression from the luxR promoter) and luciferase activity (expression from the luxICDABEG promoter) both increased by a similar amount (8-9 fold each for tonB, 2-3 fold each for tonB+) in the presence of EDDHA. Similar results were obtained with the luxR gene present on a complementing plasmid. The previously identified regulatory factors that control the lux system (autoinducer-LuxR protein, cyclic AMP-cAMP receptor protein) differentially control expression from the luxR and luxICDABEG promoters, increasing expression from one while decreasing expression from the other. Consequently, these results suggest that the effect of iron on the V. fischeri luminescence system is indirect.

Luminescence properties of KCl:Ag{sup -} crystals excited near the fundamental absorption edge

Energy Technology Data Exchange (ETDEWEB)

Kawai, Taketoshi, E-mail: buri@p.s.osakafu-u.ac.jp [Department of Physical Science, Graduate School of Science, Osaka Prefecture University, Gakuen-cho 1-1, Naka-ku, Sakai, Osaka 599-8531 (Japan); Hirai, Takeshi [Department of Physical Science, Faculty of Science and Engineering, Ritsumeikan University, Noji Higashi 1-1-1, Kusatsu, Shiga 525-8577 (Japan)

2012-02-15

Luminescence properties of KCl single crystals doped with Ag{sup -} centers have been investigated under various excitation energies around the fundamental absorption edge at low temperatures. Under the excitation at 6.89 eV, which is lower than the intrinsic exciton energy by 0.87 eV, the A Prime luminescence band due to the intraionic transition in the Ag{sup -} ion is dominantly observed at 2.91 eV. On the other hand, the excitation at 6.66 eV induces a broad luminescence band at 2.60 eV in addition to the A Prime luminescence band. From the comparison with the localized excitons in KCl:I crystals, the 2.60 eV luminescence band is attributed to the two-center type localized exciton related with the Ag{sup -} ion. The adiabatic potential energy surfaces of the excited states in the Ag{sup -} center and the localized exciton in KCl:Ag{sup -} are discussed. - Highlights: Black-Right-Pointing-Pointer We study the luminescence properties of KCl single crystals doped with Ag{sup -} ions. Black-Right-Pointing-Pointer The excitation around the absorption edge induces a broad luminescence at 2.60 eV. Black-Right-Pointing-Pointer The 2.60 eV luminescence is attributed to the exciton localized at the Ag{sup -} ion. Black-Right-Pointing-Pointer The localized exciton has the two-center type configuration of the relaxed exciton.

Phase transition and luminescence properties from vapor etched silicon

International Nuclear Information System (INIS)

Aouida, S.; Saadoun, M.; Ben Saad, K.; Bessais, B.

2006-01-01

In this work, we present a study on the structure and photoluminescence (PL) properties of a non-conventional ammonium hexafluorosilicate (NH 4 ) 2 SiF 6 (white powder) obtained from HNO 3 /HF chemical vapor etching (CVE) of silicon wafers. The CVE method leads either to the formation of luminescent Porous Silicon (PS) or SiO x /Si-containing (NH 4 ) 2 SiF 6 depending on the experimental conditions. At specific conditions (i.e., HNO 3 / HF volume ratio > 1 / 4), the CVE technique can generate instead of PS, a (NH 4 ) 2 SiF 6 phase where SiO x /Si particles are embedded. The (NH 4 ) 2 SiF 6 marketed powder is not luminescent, while that obtained from silicon vapor-etching presents a noticeable intense and stable photoluminescence (PL), which was found to have mainly two shoulders at 1.98 and 2.1 eV. Two processes have been proposed to explain this PL property. First, the visible luminescence around 1.98 eV would come from silicon nanoparticles embedded in the powder, having a distribution size that does not allow SiO x species to influence their own PL. Second, the PL shoulder around 2.1 eV would originate from small silicon nanoparticles trapped in SiO x features, leading to oxide related states that may trap electrons or excitons, depending on the silicon nanoparticle size, wherein radiative recombination occurs. The PL shoulder could become broader at low temperatures suggesting the existence of radiative recombination in SiO x related defects

Luminescence evolution of porous GaN thin films prepared via UV-assisted electrochemical etching

International Nuclear Information System (INIS)

Cheah, S.F.; Lee, S.C.; Ng, S.S.; Yam, F.K.; Abu Hassan, H.; Hassan, Z.

2015-01-01

Porous gallium nitride (GaN) thin films with different surface morphologies and free carriers properties were fabricated from Si-doped GaN thin films using ultra-violet assisted electrochemical etching approach under various etching voltages. Fluctuation of luminescence signals was observed in the photoluminescence spectra of porous GaN thin films. Taking advantage of the spectral sensitivity of infrared attenuated total reflection spectroscopy on semiconductor materials, roles of free carriers and porous structure in controlling luminescence properties of GaN were investigated thoroughly. The results revealed that enhancement in luminescence signal is not always attained upon porosification. Although porosification is correlated to the luminescence enhancement, however, free carrier is the primary factor to enhance luminescence intensity. Due to unavoidable significant reduction of free carriers from Si-doped GaN in the porosification process, control of etching depth (i.e., thickness of porous layer formed from the Si-doped layer) is critical in fabricating porous GaN thin film with enhanced luminescence response. - Highlights: • Various pore morphologies with free carrier properties are produced by Si-doped GaN. • Free carriers are important to control the luminescence signal of porous GaN. • Enhancement of luminescence signal relies on the pore depth of Si-doped layer

Luminescence Properties of Self-Aggregating TbIII-DOTA-Functionalized Calix[4]arenes

Science.gov (United States)

Mayer, Florian; Tiruvadi Krishnan, Sriram; Schühle, Daniel T.; Eliseeva, Svetlana V.; Petoud, Stéphane; Tóth, Éva; Djanashvili, Kristina

2018-01-01

Self-aggregating calix[4]arenes carrying four DOTA ligands on the upper rim for stable complexation of paramagnetic GdIII-ions have already been proposed as MRI probes. In this work, we investigate the luminescence properties of TbIII-DOTA-calix[4]arene-4OPr containing four propyl-groups and compare them with those of the analogue substituted with a phthalimide chromophore (TbIII-DOTA-calix[4]arene-3OPr-OPhth). We show that, given its four aromatic rings, the calix[4]arene core acts as an effective sensitizer of Tb-centered luminescence. Substituents on the lower rim can modulate the aggregation behavior, which in turn determines the luminescence properties of the compounds. In solid state, the quantum yield of the phthalimide derivative is almost three times as high as that of the propyl-functionalized analogue demonstrating a beneficial role of the chromophore on Tb-luminescence. In solution, however, the effect of the phthalimide group vanishes, which we attribute to the large distance between the chromophore and the lanthanide, situated on the opposite rims of the calix[4]arene. Both quantum yields and luminescence lifetimes show clear concentration dependence in solution, related to the strong impact of aggregation on the luminescence behaviour. We also evidence the variability in the values of the critical micelle concentration depending on the experimental technique. Such luminescent calix[4]arene platforms accommodating stable lanthanide complexes can be considered valuable building blocks for the design of dual MR/optical imaging probes.

Luminescence properties of the Sm-doped borate glasses

International Nuclear Information System (INIS)

Kindrat, I.I.; Padlyak, B.V.; Drzewiecki, A.

2015-01-01

The optical absorption and photoluminescence (emission and excitation) spectra as well as decay kinetics of a series of the Sm-doped glasses with Li 2 B 4 O 7 , LiKB 4 O 7 , CaB 4 O 7 , and LiCaBO 3 compositions were investigated and analysed. The Li 2 B 4 O 7 :Sm, LiKB 4 O 7 :Sm, CaB 4 O 7 :Sm, and LiCaBO 3 :Sm glasses of high optical quality have been obtained from the corresponding polycrystalline compounds in the air atmosphere, using a standard glass technology. On the basis of electron paramagnetic resonance (EPR) and optical spectra analysis it was shown that the samarium impurity is incorporated into the glass network as Sm 3+ (4f 5 , 6 H 5/2 ) ions, exclusively. All observed 4f – 4f transitions of the Sm 3+ centres in the optical absorption and luminescence spectra of the investigated glasses are identified. Most intense emission band of the Sm 3+ ions peaked about 598 nm ( 4 G 5/2 → 6 H 7/2 transition) is characterised by a single exponential decay with typical lifetime values, which depend on the basic glass composition as well as concentration and local structure of the Sm 3+ luminescence centres. The quantum efficiency has been evaluated for observed transitions of the Sm 3+ centres using obtained experimental lifetimes and radiative lifetimes calculated by Judd–Ofelt theory. The calculated high quantum efficiencies and measured quantum yields of luminescence show that the investigated borate glasses are perspective luminescence materials. Energy transfer from the Ce 3+ non-controlled impurity and intrinsic luminescence centres to the Sm 3+ centres has been observed. Peculiarities of the Sm 3+ local structure in the network of investigated glasses have been discussed based on the obtained spectroscopic results and structural data. - Highlights: • The Sm-doped Li 2 B 4 O 7 , LiKB 4 O 7 , CaB 4 O 7 , and LiCaBO 3 glasses of high quality were obtained. • EPR, optical absorption and luminescence spectra of Sm 3+ ions in obtained glasses were

High temperature luminescence of ZnSe:Yb crystals

Directory of Open Access Journals (Sweden)

Makhniy V. P.

2016-05-01

Full Text Available The problem of obtaining of effective edge luminescence with high temperature stability in the zinc selenide crystals is discussed. This task is solved by using as the dopant rare-earth element yttrium, which is introduced into the undoped ZnSe crystal by diffusion method. Doping was carried out in an evacuated to 10 -4 Torr. and a sealed quartz ampoule, in the opposite ends of which is a sample and a mixture of the crushed Yb and Se. It has been found that the diffusion coefficient of yttrium at a temperature of 1400 K is about 5⋅10 -7 cm 2/sec. It is shown that in the luminescence spectra of ZnSe:Yb samples in the temperature range 295-470 K only blue band is observed. Dependencies of parameters of this band from the excitation level are typical for the annihilation of excitons at their inelastic scattering by free carriers. The efficacy of blue radiation at 300 K is about 30% and does not fall more than twice with increasing temperature up to 470 K, indicating its high thermal stability.

Study of plant pigment concentration using synchronous luminescence spectroscopy

International Nuclear Information System (INIS)

Pawar, B.H.; Raghuvanshi, F.C.; Mahalle, N.S.; Munde, B.S.; Devhade, S.K.; Arsad, S.S.; Kadam, K.P.; Pachkawade, A.P.; Hiswankar, S.U.

2006-01-01

We have recorded the SL (Synchronous Luminescence) spectra emitted by several plant leaves. We investigate in detail SL spectra emitted by the leaf of the plants like Hibiscus Schizopetalus, Ficus Benghalensis, Ficus Religiosa and Ficus Glomerata and study the concentration of the pigments in the plant leaves and the mechanism of photosynthesis process taking place in the leaves. The SL spectra have several features which may help in revealing the density and structure of the molecules present in the samples. The SL spectra exhibit two, three, four and five peaked structure. The peak appear at different wavelengths and their spectral widths are also different. The chlorophyll, xanthophyll and carotene concentration may be obtained from the study of the spectra. The plant species may be identified from the study of SL spectroscopy. (author)

A method for the automated, reliable retrieval of publication-citation records.

Directory of Open Access Journals (Sweden)

Derek Ruths

Full Text Available BACKGROUND: Publication records and citation indices often are used to evaluate academic performance. For this reason, obtaining or computing them accurately is important. This can be difficult, largely due to a lack of complete knowledge of an individual's publication list and/or lack of time available to manually obtain or construct the publication-citation record. While online publication search engines have somewhat addressed these problems, using raw search results can yield inaccurate estimates of publication-citation records and citation indices. METHODOLOGY: In this paper, we present a new, automated method that produces estimates of an individual's publication-citation record from an individual's name and a set of domain-specific vocabulary that may occur in the individual's publication titles. Because this vocabulary can be harvested directly from a research web page or online (partial publication list, our method delivers an easy way to obtain estimates of a publication-citation record and the relevant citation indices. Our method works by applying a series of stringent name and content filters to the raw publication search results returned by an online publication search engine. In this paper, our method is run using Google Scholar, but the underlying filters can be easily applied to any existing publication search engine. When compared against a manually constructed data set of individuals and their publication-citation records, our method provides significant improvements over raw search results. The estimated publication-citation records returned by our method have an average sensitivity of 98% and specificity of 72% (in contrast to raw search result specificity of less than 10%. When citation indices are computed using these records, the estimated indices are within of the true value 10%, compared to raw search results which have overestimates of, on average, 75%. CONCLUSIONS: These results confirm that our method provides

Thermally and optically stimulated luminescence of early medieval blue-green glass mosaics

Energy Technology Data Exchange (ETDEWEB)

Galli, A. E-mail: anna.galli@mater.unimib.it; Martini, M.; Montanari, C.; Sibilia, E

2004-12-01

The preliminary results of a study related to luminescent mechanisms in glass mosaic tesserae are presented. The samples came from a medieval glass deposit found during archaeological excavations in the S. Lorenzo Church in Milan. Energy Dispersive X-rays Fluorescence (EDXRF) measurements were performed to obtain information on the elemental composition of the materials. Thermally Stimulated Luminescence (TSL, both conventional and wavelength resolved) and Optically Stimulated Luminescence (OSL) analyses allowed to get information about traps and luminescence centres. The observed luminescence characteristics were close to that of quartz, showing the presence of an easy to bleach trap (300 deg. C, 1.95 eV) and of a hard to bleach trap (350 deg. C, 2.20 eV); charge transfer phenomena, involving the low-temperature peaks have been observed. There is a strong indication that the easy to bleach traps are responsible for both OSL and TSL emission at 300 deg. C.

Thermally and optically stimulated luminescence of early medieval blue-green glass mosaics

International Nuclear Information System (INIS)

Galli, A.; Martini, M.; Montanari, C.; Sibilia, E.

2004-01-01

The preliminary results of a study related to luminescent mechanisms in glass mosaic tesserae are presented. The samples came from a medieval glass deposit found during archaeological excavations in the S. Lorenzo Church in Milan. Energy Dispersive X-rays Fluorescence (EDXRF) measurements were performed to obtain information on the elemental composition of the materials. Thermally Stimulated Luminescence (TSL, both conventional and wavelength resolved) and Optically Stimulated Luminescence (OSL) analyses allowed to get information about traps and luminescence centres. The observed luminescence characteristics were close to that of quartz, showing the presence of an easy to bleach trap (300 deg. C, 1.95 eV) and of a hard to bleach trap (350 deg. C, 2.20 eV); charge transfer phenomena, involving the low-temperature peaks have been observed. There is a strong indication that the easy to bleach traps are responsible for both OSL and TSL emission at 300 deg. C

Optical stimulated luminescence (OSL) dating

International Nuclear Information System (INIS)

Banerjee, D.

1999-01-01

Since the pioneering work by Huntley et al. (1985), optical dating is being increasingly recognised as an important technique for establishing a time frame of deposition of sediments (Aitken, 1998). Optical dating differs from thermoluminescence (TL) dating in that visible/infrared light from lasers or LEDs (light-emitting-diodes) is used as a means of stimulation, in contrast to thermal stimulation. It has several advantages over TL dating: (i) the resetting of the OSL (optically stimulated luminescence) clock is more effective than that of TL clock; for sediments transported under water or in other situations where the sediment grains have undergone inhomogeneous bleaching, this property ensures that ages based on optical dating are generally more reliable than TL ages, (ii) the optical dating technique is non-destructive, and multiple readouts of the optical signal is possible; this feature has resulted in the development of single-aliquot and single-grain protocols (Murray and Wintle, 1999; Banerjee et al. 1999), (iii) the sample is not heated as in TL; thus, spurious luminescence is avoided and there is a significant reduction in blackbody radiation. Dating of materials which change phase on heating is also practical, and finally, (iv) thermal quenching of luminescence is negligible, allowing accurate estimation of kinetic parameters using standard techniques and providing access to deep OSL traps. This characteristic may be helpful in extending the limits of optical dating beyond the last 150 ka from a global point of view

An optically stimulated luminescence study of porcelain related to radiation dosimetry

DEFF Research Database (Denmark)

Poolton, N.R.J.; Bøtter-Jensen, L.; Jungner, H.

1995-01-01

Stokes and anti-Stokes shifted in energy. Glazing is shown in some cases to be considerably more sensitive as a radiation dosemeter than the main porcelain ceramic. By comparison with the properties of artifical phosphors, the principal luminescent matrix is identified as being Al2O3......This article describes the essential features regarding the photo-stimulated luminescence of porcelain: both the main ceramic and glazing materials are studied. In each case, radiation dose dependent signals are observed, superimposed on dose independent luminescence transitions that are both...

Optical and luminescence properties of zinc oxide (Review)

Science.gov (United States)

Rodnyi, P. A.; Khodyuk, I. V.

2011-11-01

We generalize and systematize basic experimental data on optical and luminescence properties of ZnO single crystals, thin films, powders, ceramics, and nanocrystals. We consider and study mechanisms by which two main emission bands occur, a short-wavelength band near the fundamental absorption edge and a broad long-wavelength band, the maximum of which usually lies in the green spectral range. We determine a relationship between the two luminescence bands and study in detail the possibility of controlling the characteristics of ZnO by varying the maximum position of the short-wavelength band. We show that the optical and luminescence characteristics of ZnO largely depend on the choice of the corresponding impurity and the parameters of the synthesis and subsequent treatment of the sample. Prospects for using zinc oxide as a scintillator material are discussed. Additionally, we consider experimental results that are of principal interest for practice.

Optically stimulated luminescence dosimetry with gypsum wallboard (drywall)

International Nuclear Information System (INIS)

Thompson, J. W.; Burdette, K. E.; Inrig, E. L.; Dewitt, R.; Mistry, R.; Rink, W. J.; Boreham, D. R.

2010-01-01

Gypsum wallboard (drywall) represents an attractive target for retrospective dosimetry by optically stimulated luminescence (OSL) in the event of a radiological accident or malicious use of nuclear material. In this study, wallboard is shown to display a radiation-induced luminescence signal (RIS) as well as a natural background signal (NS), which is comparable in intensity to the RIS. Excitation and emission spectra show that maximum luminescence intensity is obtained for stimulation with blue light-emitting diodes (470 nm) and for detection in the ultraviolet region (290-370 nm). It is necessary to decrease the optical stimulation power dramatically in order to adequately separate the RIS from the interfering background signal. The necessary protocols are developed for accurately measuring the absorbed dose as low as 500 mGy and demonstrate that the RIS decays logarithmically with storage time, with complete erasure expected within 1-4 d. (authors)

Synthesis and Features of Luminescent Bromo- and Iodohectorite Nanoclay Materials

Directory of Open Access Journals (Sweden)

Hellen Silva Santos

2017-11-01

Full Text Available The smectites represent a versatile class of clay minerals with broad usage in industrial applications, e.g., cosmetics, drug delivery, bioimaging, etc. Synthetic hectorite Na0.7(Mg5.5Li0.3[Si8O20](OH4 is a distinct material from this class due to its low-cost production method that allows to design its structure to match better the applications. In the current work, we have synthesized for the first time ever nanoclay materials based on the hectorite structure but with the hydroxyl groups (OH− replaced by Br− or I−, yielding bromohectorite (Br-Hec and iodohectorite (I-Hec. It was aimed that these materials would be used as phosphors. Thus, OH− replacement was done to avoid luminescence quenching by multiphonon de-excitation. The crystal structure is similar to nanocrystalline fluorohectorite, having the d001 spacing of 14.30 Å and 3 nm crystallite size along the 00l direction. The synthetic materials studied here show strong potential to act as host lattices for optically active species, possessing mesoporous structure with high specific surface area (385 and 363 m2 g−1 for Br-Hec and I-Hec, respectively and good thermal stability up to 800 °C. Both materials also present strong blue-green emission under UV radiation and short persistent luminescence (ca. 5 s. The luminescence features are attributed to Ti3+/TiIV impurities acting as the emitting center in these materials.

Influence of silver and copper doping on luminescent properties of zinc-phosphate glasses after x-ray irradiation

Science.gov (United States)

Murashov, Alexander A.; Sidorov, Alexander I.; Shakhverdov, Teimur A.; Stolyarchuk, Maxim V.

2017-11-01

It is shown, experimentally, that in silver- and copper-containing zinc-phosphate glasses, metal molecular clusters are formed during the glass synthesis. X-ray irradiation of these glasses led to the considerable increase of its luminescence in visible spectral range. This effect is caused by the transformation of the charged metal molecular clusters into the neutral state. Luminescence and excitation spectra of the glass, doped with silver and copper simultaneously, change significantly in comparison with the spectra of glasses doped with one metal. The reason for this can be the formation of hybrid AgnCum molecular clusters. The computer simulation of the structure and optical properties of such clusters by the time-dependent density functional theory method is presented. It is shown that the optimal luminescent material for photonics application, in comparison with other studied materials, is glass, containing hybrid molecular clusters.

Cathode and ion-luminescence of Eu:ZnO thin films prepared by reactive magnetron sputtering and plasma decomposition of non-volatile precursors

Energy Technology Data Exchange (ETDEWEB)

Gil-Rostra, Jorge [Instituto de Ciencia de Materiales de Sevilla, CSIC, Univ. Sevilla, C/Américo Vespucio 49, E-41092 Sevilla (Spain); Ferrer, Francisco J. [Centro Nacional de Aceleradores, CSIC, Univ. Sevilla, Av. Thomas A. Edison 7, E-41092 Sevilla (Spain); Martín, Inocencio R. [Departamento de Física Fundamental y Experimental, Electrónica y Sistemas, U. La Laguna, C/Astrofísico Francisco Sánchez s/n, E-38206 La Laguna, Santa Cruz de Tenerife (Spain); González-Elipe, Agustín R.; Yubero, Francisco [Instituto de Ciencia de Materiales de Sevilla, CSIC, Univ. Sevilla, C/Américo Vespucio 49, E-41092 Sevilla (Spain)

2016-10-15

This paper reports the luminescent behavior of Eu:ZnO thin films prepared by an one-step procedure that combines reactive magnetron sputtering deposition of ZnO with the plasma activated decomposition of a non-volatile acetylacetonate precursor of Eu sublimated in an effusion cell. Chemical composition and microstructure of the Eu:ZnO thin films have been characterized by several methods and their photo-, cathode- and ion-luminescent properties studied as a function of Eu concentration. The high transparency and well controlled optical properties of the films have demonstrated to be ideal for the development of cathode- and ion- luminescence sensors.

Luminescent screens

International Nuclear Information System (INIS)

Lu, C.-I.

1982-01-01

Luminescent screens which are useful for such purposes as intensifying screens for radiographs are comprised of a support bearing a layer of finely divided particles of a phosphor dispersed in a cross-linked polymeric matrix formed by heat-curing of a coating composition comprising an unsaturated cross-linkable polymer, a polymerizable acrylic monomer, a thermoplastic polyurethane elastomer, and a heat-activatable polymerization initiator. The phosphor layer includes voids formed by evaporation of an evaporable component which is present in the coating composition from which such layer is formed. (author)

Origin of green luminescence in hydrothermally grown ZnO single crystals

Energy Technology Data Exchange (ETDEWEB)

Čížek, J., E-mail: jakub.cizek@mff.cuni.cz; Hruška, P.; Melikhova, O.; Procházka, I. [Department of Low-Temperature Physics, Charles University in Prague, V Holešovičkách 2, CZ-180 00, Prague 8 (Czech Republic); Valenta, J. [Department of Chemical Physics and Optics, Charles University in Prague, Ke Karlovu 3, CZ-121 16, Prague 2 (Czech Republic); Novotný, M.; Bulíř, J. [Academy of Science of the Czech Republic, Institute of Physics, Na Slovance 2, CZ-182 21 Praha 8 (Czech Republic)

2015-06-22

Combining photoluminescence and positron annihilation studies of hydrothermally grown ZnO crystals with stoichiometry varied by controlled annealing enabled us to clarify the origin of green luminescence. It was found that green luminescence in ZnO has multiple origins and consists of a band at 2.3(1) eV due to recombination of electrons of the conduction band by zinc vacancy acceptors coupled with hydrogen and a band at 2.47(2) eV related to oxygen vacancies. The as-grown ZnO crystals contain zinc vacancies associated with hydrogen and exhibit a green luminescence at 2.3(1) eV. Annealing in Zn vapor removed zinc vacancies and introduced oxygen vacancies. This led to disappearance of the green luminescence band at 2.3(1) eV and appearance of a green emission at higher energy of 2.47(2) eV. Moreover, the color of the crystal was changed from colorless to dark red. In contrast, annealing of the as-grown crystal in Cd vapor did not remove zinc vacancies and did not cause any significant change of green luminescence nor change in coloration.

Origin of green luminescence in hydrothermally grown ZnO single crystals

International Nuclear Information System (INIS)

Čížek, J.; Hruška, P.; Melikhova, O.; Procházka, I.; Valenta, J.; Novotný, M.; Bulíř, J.

2015-01-01

Combining photoluminescence and positron annihilation studies of hydrothermally grown ZnO crystals with stoichiometry varied by controlled annealing enabled us to clarify the origin of green luminescence. It was found that green luminescence in ZnO has multiple origins and consists of a band at 2.3(1) eV due to recombination of electrons of the conduction band by zinc vacancy acceptors coupled with hydrogen and a band at 2.47(2) eV related to oxygen vacancies. The as-grown ZnO crystals contain zinc vacancies associated with hydrogen and exhibit a green luminescence at 2.3(1) eV. Annealing in Zn vapor removed zinc vacancies and introduced oxygen vacancies. This led to disappearance of the green luminescence band at 2.3(1) eV and appearance of a green emission at higher energy of 2.47(2) eV. Moreover, the color of the crystal was changed from colorless to dark red. In contrast, annealing of the as-grown crystal in Cd vapor did not remove zinc vacancies and did not cause any significant change of green luminescence nor change in coloration

Origin of green luminescence in hydrothermally grown ZnO single crystals

Science.gov (United States)

Čížek, J.; Valenta, J.; Hruška, P.; Melikhova, O.; Procházka, I.; Novotný, M.; Bulíř, J.

2015-06-01

Combining photoluminescence and positron annihilation studies of hydrothermally grown ZnO crystals with stoichiometry varied by controlled annealing enabled us to clarify the origin of green luminescence. It was found that green luminescence in ZnO has multiple origins and consists of a band at 2.3(1) eV due to recombination of electrons of the conduction band by zinc vacancy acceptors coupled with hydrogen and a band at 2.47(2) eV related to oxygen vacancies. The as-grown ZnO crystals contain zinc vacancies associated with hydrogen and exhibit a green luminescence at 2.3(1) eV. Annealing in Zn vapor removed zinc vacancies and introduced oxygen vacancies. This led to disappearance of the green luminescence band at 2.3(1) eV and appearance of a green emission at higher energy of 2.47(2) eV. Moreover, the color of the crystal was changed from colorless to dark red. In contrast, annealing of the as-grown crystal in Cd vapor did not remove zinc vacancies and did not cause any significant change of green luminescence nor change in coloration.

Synthesis and luminescent properties of PEO/lanthanide oxide nanoparticle hybrid films

Energy Technology Data Exchange (ETDEWEB)

Goubard, F. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France)]. E-mail: fabrice.goubard@u-cergy.fr; Vidal, F. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France); Bazzi, R. [LPCML, Universite Lyon 1, 43 Bd. du 11 Novembre 1918, 69622 Villeurbanne (France); Tillement, O. [LPCML, Universite Lyon 1, 43 Bd. du 11 Novembre 1918, 69622 Villeurbanne (France); Nano-H, 23 rue Royal, 69001 Lyon (France); Chevrot, C. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France); Teyssie, D. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France)

2007-10-15

In this study, we investigate the optical properties of lanthanide oxide nanoparticles dispersed in poly(ethylene oxide) (PEO) network as thermally stable polymeric films. The aim of this work is both to keep a good optical transparency in the visible domain and to obtain luminescent materials after incorporation of nanoparticles. For this purpose, we develop luminescent nanocrystals of oxides containing terbium ion as a doping element in Gd{sub 2}O{sub 3}. These sub-5-nm lanthanide oxides nanoparticles have been prepared by direct oxide precipitation in high-boiling polyalcohol solutions and characterized by luminescence spectroscopy. PEO/lanthanide oxide nanohybrid films are prepared by radical polymerization of poly(ethylene glycol) methacrylate after introduction of lanthanide oxide particles. As a first result; the obtained films present interesting luminescence properties with a very low lanthanide oxide content (up to 0.29 wt%). Furthermore, these films are still transparent and keep their original mechanical properties. Prior to describe the specific applications to optical use, we report here the dynamic mechanical analysis (DMA), X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), and luminescent properties of. nanohybrid films.

Hybrid silica luminescent materials based on lanthanide-containing lyotropic liquid crystal with polarized emission

Energy Technology Data Exchange (ETDEWEB)

Selivanova, N.M., E-mail: natsel@mail.ru [Kazan National Research Technological University, 68 Karl Marx Str., Kazan 420015 (Russian Federation); Vandyukov, A.E.; Gubaidullin, A.T. [A.E. Arbuzov Institute of Organic and Physical Chemistry of the Kazan Scientific Center of the Russian Academy of Sciences, 8 Acad. Arbuzov Str., Kazan 420088 (Russian Federation); Galyametdinov, Y.G. [Kazan National Research Technological University, 68 Karl Marx Str., Kazan 420015 (Russian Federation)

2014-11-14

This paper represents the template method for synthesis of hybrid silica films based on Ln-containing lyotropic liquid crystal and characterized by efficient luminescence. Luminescence films were prepared in situ by the sol–gel processes. Lyotropic liquid crystal (LLC) mesophases C{sub 12}H{sub 25}O(CH{sub 2}CH{sub 2}O){sub 10}H/Ln(NO{sub 3}){sub 3}·6H{sub 2}O/H{sub 2}O containing Ln (III) ions (Dy, Tb, Eu) were used as template. Polarized optical microscopy, X-ray powder diffraction, and FT-IR-spectroscopy were used for characterization of liquid crystal mesophases and hybrid films. The morphology of composite films was studied by the atomic force microscopy method (AFM). The optical properties of the resulting materials were evaluated. It was found that hybrid silica films demonstrate significant increase of their lifetime in comparison with an LLC system. New effects of linearly polarized emission revealed for Ln-containing hybrid silica films. Polarization in lanthanide-containing hybrid composites indicates that silica precursor causes orientation of emitting ions. - Highlights: • We suggest a new simple approach for creating luminescence hybrid silica films. • Ln-containing hybrid silica films demonstrate yellow, green and red emissions. • Tb(III)-containing hybrid film have a high lifetime. • We report effects of linearly polarized emission in hybrid film.

High-resolution light microscopy using luminescent nanoparticles.

Science.gov (United States)

Ohulchanskyy, Tymish Y; Roy, Indrajit; Yong, Ken-Tye; Pudavar, Haridas E; Prasad, Paras N

2010-01-01

This review presents recent progress in the development of the luminescent nanoparticles for confocal and multiphoton microscopy. Four classes of nanomaterials are discussed: (1) silica-based nanoparticles doped with fluorescent molecules, (2) gold nanoparticles, (3) semiconductor nanocrystals (quantum dots/rods), and (4) nanophosphors. Special considerations are given to recently developed imaging nanoprobes, such as (1) organically modified silica (ORMOSIL) nanoparticles doped with two-photon absorbing fluorophores, which exhibit aggregation-enhanced fluorescence (AEF), and (2) nanophosphors (ceramic nanoparticles containing luminescent lanthanoid ions). Advantages and disadvantages of every class of nanomaterials and their specific applications are briefly discussed.

Record-keeping as an Alternative Method οf Assessment

Directory of Open Access Journals (Sweden)

Androniki Kouvdou

2010-02-01

Full Text Available The basic topic of this chapter is the description of an alternative method of assessment which supplements traditional objective techniques (i.e. testing, while counterbalancing their limitations. This alternative method, known as ‘record-keeping’, involves the systematic collection and recording of information about learner progress and aims at providing a more complete and valid formative assessment of their developmental abilities in specified areas. More particularly, this chapter presents a small-scale case study, which was carried out in the sixth grade of a primary school and lasted three months. The subjects of this case study were four twelve-year-old learners and its purpose was to investigate the potential of ‘record-keeping’ as an alternative method of assessing oracy skills in the foreign language. The data that derived from the case study reinforce the usefulness and validity of the particular method of assessment. The goals of the experimental assessment design, which entailed the recording and gradual development of learner oracy skills as well as the enhancement of motivation and awareness of their relevant sub-skills, were accomplished to a considerable degree. Additionally, the learners responded positively to the implemented assessment project, while being actively involved in it, which further substantiates its effectiveness. Alternative assessment, however, is a large area, whose full potential of implementation calls for further investigation.

Dental diagnostic clinical instrument (Canary) development using photothermal radiometry and modulated luminescence

International Nuclear Information System (INIS)

Jeon, R J; Sivagurunathan, K; Garcia, J; Matvienko, A; Mandelis, A; Abrams, S

2010-01-01

Since 1999, our group at the CADIFT, University of Toronto, has developed the application of Frequency Domain Photothermal Radiometry (PTR) and Luminescence (LUM) to dental caries detection. Various cases including artificial caries detection have been studied and some of the inherent advantages of the adaptation of this technique to dental diagnostics in conjunction with modulated luminescence as a dual-probe technique have been reported. Based on these studies, a portable, compact diagnostic instrument for dental clinic use has been designed, assembled and tested. A semiconductor laser, optical fibers, a thermoelectric cooled mid-IR detector, and a USB connected data acquisition card were used. Software lock-in amplifier techniques were developed to compute amplitude and phase of PTR and LUM signals. In order to achieve fast measurement and acceptable signal-to-noise ratio (SNR) for clinical application, swept sine waveforms were used. As a result sampling and stabilization time for each measurement point was reduced to a few seconds. A sophisticated software interface was designed to simultaneously record intra-oral camera images with PTR and LUM responses. Preliminary results using this instrument during clinical trials in a dental clinic showed this instrument could detect early caries both from PTR and LUM signals.

Hydrothermal synthesis, characterization and luminescent ...

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science; Volume 39; Issue 4. Hydrothermal synthesis, characterization and luminescent properties of lanthanide-doped NaLaF 4 nanoparticles. JIGMET LADOL HEENA KHAJURIA SONIKA KHAJURIA ... Keywords. Citric acid; X-ray diffraction; down-conversion emission; energy transfer.

Luminescent properties of LuPO4-Pr and LuPO4-Eu nanoparticles

International Nuclear Information System (INIS)

Vistovskyy, V.; Malyi, T.; Vas’kiv, A.; Chylii, M.; Mitina, N.; Zaichenko, A.; Gektin, A.; Voloshinovskii, A.

2016-01-01

Spectral-luminescence parameters of LuPO 4 -Eu and LuPO 4 -Pr nanoparticles of different sizes are studied upon excitation by the synchrotron radiation with photon energies 4–40 eV. Influence of the nanoparticle size on Eu 3+ and Pr 3+ impurity luminescence is analyzed for intracenter and recombination excitation. It is shown that the luminescence intensity of impurities in the case of recombination excitation significantly stronger decreases with decreasing of nanoparticle size compared to intracenter excitation. This feature is explained by the influence of thermalization length to nanoparticle size ratio on the recombination luminescence. Electron recombination luminescence inherent for LuPO 4 -Eu nanoparticles shows a weaker dependence on the nanoparticle size than the hole one in LuPO 4 -Pr nanoparticles. The difference between energy states of praseodymium impurity ions in nanoparticles of different sizes is revealed.

Luminescence Properties of Self-Aggregating TbIII-DOTA-Functionalized Calix[4]arenes

Directory of Open Access Journals (Sweden)

Florian Mayer

2018-01-01

Full Text Available Self-aggregating calix[4]arenes carrying four DOTA ligands on the upper rim for stable complexation of paramagnetic GdIII-ions have already been proposed as MRI probes. In this work, we investigate the luminescence properties of TbIII-DOTA-calix[4]arene-4OPr containing four propyl-groups and compare them with those of the analog substituted with a phthalimide chromophore (TbIII-DOTA-calix[4]arene-3OPr-OPhth. We show that, given its four aromatic rings, the calix[4]arene core acts as an effective sensitizer of Tb-centered luminescence. Substituents on the lower rim can modulate the aggregation behavior, which in turn determines the luminescence properties of the compounds. In solid state, the quantum yield of the phthalimide derivative is almost three times as high as that of the propyl-functionalized analog demonstrating a beneficial role of the chromophore on Tb-luminescence. In solution, however, the effect of the phthalimide group vanishes, which we attribute to the large distance between the chromophore and the lanthanide, situated on the opposite rims of the calix[4]arene. Both quantum yields and luminescence lifetimes show clear concentration dependence in solution, related to the strong impact of aggregation on the luminescence behavior. We also evidence the variability in the values of the critical micelle concentration depending on the experimental technique. Such luminescent calix[4]arene platforms accommodating stable lanthanide complexes can be considered valuable building blocks for the design of dual MR/optical imaging probes.

Circularly Polarized Luminescence from Inorganic Materials: Encapsulating Guest Lanthanide Oxides in Chiral Silica Hosts.

Science.gov (United States)

Sugimoto, Masumi; Liu, Xin-Ling; Tsunega, Seiji; Nakajima, Erika; Abe, Shunsuke; Nakashima, Takuya; Kawai, Tsuyoshi; Jin, Ren-Hua

2018-05-02

Recently, circularly polarized luminescence (CPL)-active systems have become a very hot and interesting subject in chirality- and optics-related areas. The CPL-active systems are usually available by two approaches: covalently combining a luminescent centre to chiral motif or associating the guest of luminescent probe to a chiral host. However, all the chiral components in CPL materials were organic, although the luminescent components were alternatively organics or inorganics. Herein, the first totally inorganic CPL-active system by "luminescent guest-chiral host" strategy is proposed. Luminescent sub-10 nm lanthanide oxides (Eu 2 O 3 or Tb 2 O 3 ) nanoparticles (guests) were encapsulated into chiral non-helical SiO 2 nanofibres (host) through calcination of chiral SiO 2 hybrid nanofibres, trapping Eu 3+ (or Tb 3+ ). These lanthanide oxides display circular dichroism (CD) optical activity in the ultraviolet wavelength and CPL signals around at 615 nm for Eu 3+ and 545 nm for Tb 3+ . This work has implications for inorganic-based CPL-active systems by incorporation of various luminescent guests within chiral inorganic hosts. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Growth and luminescence properties of Pr3+-doped single crystalline films of garnets and perovskites

International Nuclear Information System (INIS)

Gorbenko, V.; Zorenko, Yu.; Savchyn, V.; Zorenko, T.; Pedan, A.; Shkliarskyi, V.

2010-01-01

Peculiarities of growth of single crystalline films (SCF) of Pr 3+ doped Y 3 Al 5 O 12 and Lu 3 Al 5 O 12 garnets and YAlO 3 and LuAlO 3 perovskites by the liquid phase epitaxy method from melt-solutions based on PbO-B 2 O 3 flux as well as luminescent and scintillation properties of these SCFs were studied in this work. Dependence the intensity of the Pr 3+ d-f and f-f-luminescence on the activator concentration and influence of Pb 2+ flux dopant on the light yield of SCFs of the mentioned garnets and perovskites were analyzed.

Spatially-resolved luminescence spectroscopy of CdSe quantum dots synthesized in ionic liquid crystal matrices

Energy Technology Data Exchange (ETDEWEB)

Magaryan, K.A., E-mail: xmagaros@gmail.com [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Mikhailov, M.A. [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Karimullin, K.R. [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Institute for Spectroscopy of RAS, 5 Fizicheskaya Str., Troitsk, Moscow 142190 (Russian Federation); E.K. Zavoyski Kazan Physical-Technical Institute of RAS, 10/7 Sibirski trakt Str., Kazan 420029 (Russian Federation); Knyazev, M.V.; Eremchev, I.Y. [Institute for Spectroscopy of RAS, 5 Fizicheskaya Str., Troitsk, Moscow 142190 (Russian Federation); Naumov, A.V. [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Institute for Spectroscopy of RAS, 5 Fizicheskaya Str., Troitsk, Moscow 142190 (Russian Federation); Vasilieva, I.A. [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Klimusheva, G.V. [Institute of Physics, NAS of Ukraine, 46 Prospect Nauki, Kiev 03028 (Ukraine)

2016-01-15

The paper is devoted to investigation of luminescence properties of new quantum dot (QD)-doped materials. We studied CdSe QDs (1.8 nm and 2.3 nm) grown inside of a liquid crystalline cadmium alcanoate matrix. Temperature dependence of parameters of fluorescence spectra obtained in a wide temperature range using epi-luminescence microscopy technique was analyzed. Spatially-resolved luminescence images were measured for the areas of the samples of 150×150 µm{sup 2}. Strong correlation between fluorescence spectra and sample structure was observed. - Highlights: • Glassy matrix with CdSe quantum dots inside fabricated in liquid crystalline mesophase. • Study of luminescence properties in a wide range of low temperatures. • Strong dependence of the luminescence spectra on spatial inhomogeneities. • Spatially-resolved luminescence imaging of quantum dots in liquid crystalline matrix.

Spatially-resolved luminescence spectroscopy of CdSe quantum dots synthesized in ionic liquid crystal matrices

International Nuclear Information System (INIS)

Magaryan, K.A.; Mikhailov, M.A.; Karimullin, K.R.; Knyazev, M.V.; Eremchev, I.Y.; Naumov, A.V.; Vasilieva, I.A.; Klimusheva, G.V.

2016-01-01

The paper is devoted to investigation of luminescence properties of new quantum dot (QD)-doped materials. We studied CdSe QDs (1.8 nm and 2.3 nm) grown inside of a liquid crystalline cadmium alcanoate matrix. Temperature dependence of parameters of fluorescence spectra obtained in a wide temperature range using epi-luminescence microscopy technique was analyzed. Spatially-resolved luminescence images were measured for the areas of the samples of 150×150 µm 2 . Strong correlation between fluorescence spectra and sample structure was observed. - Highlights: • Glassy matrix with CdSe quantum dots inside fabricated in liquid crystalline mesophase. • Study of luminescence properties in a wide range of low temperatures. • Strong dependence of the luminescence spectra on spatial inhomogeneities. • Spatially-resolved luminescence imaging of quantum dots in liquid crystalline matrix.

X-ray excited luminescence of polystyrene composites loaded with SrF{sub 2} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Demkiv, T.M.; Halyatkin, O.O.; Vistovskyy, V.V. [Ivan Franko National University of Lviv, 8a Kyryla i Mefodiya St., 79005 Lviv (Ukraine); Hevyk, V.B. [Ivano-Frankivsk National Technical University of Oil and Gas, 15 Karpatska St., 76019 Ivano-Frankivsk (Ukraine); Yakibchuk, P.M. [Ivan Franko National University of Lviv, 8a Kyryla i Mefodiya St., 79005 Lviv (Ukraine); Gektin, A.V. [Institute for Scintillation Materials, NAS of Ukraine, 60 Lenina Ave, 61001 Kharkiv (Ukraine); Voloshinovskii, A.S. [Ivan Franko National University of Lviv, 8a Kyryla i Mefodiya St., 79005 Lviv (Ukraine)

2017-03-01

The polystyrene film nanocomposites of 0.3 mm thickness with embedded SrF{sub 2} nanoparticles up to 40 wt% have been synthesized. The luminescent and kinetic properties of the polystyrene composites with embedded SrF{sub 2} nanoparticles upon the pulse X-ray excitation have been investigated. The luminescence intensity of the pure polystyrene scintillator film significantly increases when it is loaded with the inorganic SrF{sub 2} nanoparticles. The film nanocomposites show fast (∼2.8 ns) and slow (∼700 ns) luminescence decay components typical for a luminescence of polystyrene activators (p-Terphenyl and POPOP) and SrF{sub 2} nanoparticles, respectively. It is revealed that the fast decay luminescence component of the polystyrene composites is caused by the excitation of polystyrene by the photoelectrons escaped from the nanoparticles due to photoeffect, and the slow component is caused by reabsorption of the self-trapped exciton luminescence of SrF{sub 2} nanoparticles by polystyrene.

ZnO Luminescence and scintillation studied via photoexcitation, X-ray excitation, and gamma-induced positron spectroscopy

Science.gov (United States)

Ji, J.; Colosimo, A. M.; Anwand, W.; Boatner, L. A.; Wagner, A.; Stepanov, P. S.; Trinh, T. T.; Liedke, M. O.; Krause-Rehberg, R.; Cowan, T. E.; Selim, F. A.

2016-08-01

The luminescence and scintillation properties of ZnO single crystals were studied by photoluminescence and X-ray-induced luminescence (XRIL) techniques. XRIL allowed a direct comparison to be made between the near-band emission (NBE) and trap emissions providing insight into the carrier recombination efficiency in the ZnO crystals. It also provided bulk luminescence measurements that were not affected by surface states. The origin of a green emission, the dominant trap emission in ZnO, was then investigated by gamma-induced positron spectroscopy (GIPS) - a unique defect spectroscopy method that enables positron lifetime measurements to be made for a sample without contributions from positron annihilation in the source materials. The measurements showed a single positron decay curve with a 175 ps lifetime component that was attributed to Zn vacancies passivated by hydrogen. Both oxygen vacancies and hydrogen-decorated Zn vacancies were suggested to contribute to the green emission. By combining scintillation measurements with XRIL, the fast scintillation in ZnO crystals was found to be strongly correlated with the ratio between the defect luminescence and NBE. This study reports the first application of GIPS to semiconductors, and it reveals the great benefits of the XRIL technique for the study of emission and scintillation properties of materials.

Luminescence of quartz and feldspar fingerprints provenance and correlates with the source area denudation in the Amazon River basin

Science.gov (United States)

Sawakuchi, A. O.; Jain, M.; Mineli, T. D.; Nogueira, L.; Bertassoli, D. J.; Häggi, C.; Sawakuchi, H. O.; Pupim, F. N.; Grohmann, C. H.; Chiessi, C. M.; Zabel, M.; Mulitza, S.; Mazoca, C. E. M.; Cunha, D. F.

2018-06-01

The Amazon region hosts the world's largest watershed spanning from high elevation Andean terrains to lowland cratonic shield areas in tropical South America. This study explores variations in optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL) signals in suspended silt and riverbed sands retrieved from major Amazon rivers. These rivers drain Pre-Cambrian to Cenozoic source rocks in areas with contrasting denudation rates. In contrast to the previous studies, we do not observe an increase in the OSL sensitivity of quartz with transport distance; for example, Tapajós and Xingu Rivers show more sensitive quartz than Solimões and Madeira Rivers, even though the latter have a significantly larger catchment area and longer sediment transport distance. Interestingly, high sensitivity quartz is observed in rivers draining relatively stable Central Brazil and Guiana shield areas (denudation rate ξ = 0.04 mmyr-1), while low sensitivity quartz occurs in less stable Andean terrains (ξ = 0.24 mmyr-1). An apparent linear correlation between quartz OSL sensitivity and denudation rate suggests that OSL sensitivity may be used as a proxy for erosion rates in the Amazon basin. Furthermore, luminescence sensitivity measured in sand or silt arises from the same mineral components (quartz and feldspar) and clearly discriminates between Andean and shield sediments, avoiding the grain size bias in provenance analysis. These results have implications for using luminescence sensitivity as a proxy for Andean and shield contributions in the stratigraphic record, providing a new tool to reconstruct past drainage configurations within the Amazon basin.

Structural, vibrational and luminescence properties of the (1−x)CaWO{sub 4}−xCdWO{sub 4} system

Energy Technology Data Exchange (ETDEWEB)

Taoufyq, A. [Institut Matériaux Microélectronique et Nanosciences de Provence, Aix Marseille Université, CNRS, Université de Toulon, IM2NP UMR 7334, 83957, La Garde (France); Laboratoire Matériaux et Environnement LME, Faculté des Sciences, Université Ibn Zohr, BP 8106, Cité Dakhla, Agadir, Maroc (Morocco); CEA/DEN, Département d’Études des Réacteurs, Laboratoire Dosimétrie Capteurs Instrumentation, CEA Cadarache, 13108, Saint-Paul-lez-Durance (France); Société CESIGMA, Signals and Systems, 1576 Chemin de La Planquette, 83130 La Garde (France); Guinneton, F.; Valmalette, J-C.; Arab, M. [Institut Matériaux Microélectronique et Nanosciences de Provence, Aix Marseille Université, CNRS, Université de Toulon, IM2NP UMR 7334, 83957, La Garde (France); Benlhachemi, A.; Bakiz, B. [Laboratoire Matériaux et Environnement LME, Faculté des Sciences, Université Ibn Zohr, BP 8106, Cité Dakhla, Agadir, Maroc (Morocco); Villain, S. [Institut Matériaux Microélectronique et Nanosciences de Provence, Aix Marseille Université, CNRS, Université de Toulon, IM2NP UMR 7334, 83957, La Garde (France); and others

2014-11-15

In the present work, we investigate the structural, microstructural, vibrational and luminescence properties of the system (1−x)CaWO{sub 4}−xCdWO{sub 4} with x ranging between 0 and 1. Polycrystalline samples were elaborated using a coprecipitation technique followed by thermal treatment at 1000 °C. The samples were then characterized using X-ray diffraction, scanning electron microscopy, Raman spectroscopy and luminescence analyses. X-ray diffraction profile analyses using Rietveld method showed that two kinds of solid solutions Ca{sub 1−x}Cd{sub x}WO{sub 4} having scheelite and wolframite structures, with respectively tetragonal and monoclinic crystal cells, were observed, with a biphasic system for compositions x=0.6 and 0.7. The scanning electron microscopy experiments showed a complex evolution of morphologies and crystallite sizes as x increased. The vibration modes of Raman spectra were characteristic of composition-dependent disordered solid solutions with decreasing wavenumbers as x increased. Luminescence experiments were performed under UV-laser light irradiation. The energies of emission bands increased linearly with cadmium composition x. The integrated intensity of luminescence reached a maximum value for the substituted wolframite phase with composition x=0.8. - Graphical abstract: Luminescence on UV excitation (364.5 nm) of (1−x)CaWO{sub 4−x}CdWO{sub 4} system, elaborated from coprecipitation technique at 1000 °C, with 0luminescence intensity for the composition x=0.8. - Highlights: • Solid solutions Ca{sub 1−x}Cd{sub x}WO{sub 4} are elaborated from coprecipitation technique. • The structures of two types of solid solutions are refined using Rietveld method. • A maximum of luminescence is obtained for an intermediate composition x=0.8.

Thermally stimulated luminescence and persistent luminescence of β-irradiated YAG:Pr"3"+ nanophosphors produced by combustion synthesis

International Nuclear Information System (INIS)

Santacruz-Gomez, K.; Meléndrez, R.; Gil-Tolano, M.I.; Jimenez, J.A.; Makale, M.T.; Barboza-Flores, M.; Castaneda, B.; Soto-Puebla, D.; Pedroza-Montero, M.; McKittrick, J.; Hirata, G.A.

2016-01-01

In this work, the thermally stimulated luminescence (TSL) and persistent luminescence (PLUM) properties of praseodymium doped yttrium aluminum garnet (YAG:Pr"3"+) exposed to β-irradiation are reported. X-ray diffraction (XRD) confirms a single phase of YAG obtained by the combustion method. Transmission electron microscopy (TEM) shows that powder particles appear to be irregular crystals with an average size of 67 nm. TSL glow-curve deconvolution of YAG:Pr"3"+ after β-irradiation consist in six peaks centered at 394, 450, 467, 543, 637 and 705 K. The TSL fading and PLUM signals were found to be associated with at least with two different kinds of traps, corresponding to the peaks located at 394, 450 and 467 K. YAG:Pr"3"+ nanophosphors analyzed in this work showed interesting features about the dosimetric sensitivity as well as the reproducibility for both TSL/PLUM techniques, with good linearity dose response. These results indicate that nanocrystalline YAG:Pr3"+ is a good candidate for dosimetric applications in the range of 80 mGy-20 Gy. - Highlights: • β-irradiated YAG:Pr"3"+ TSL consist in 394, 450, 467, 543, 637 and 705 K peaks. • YAG:Pr"3"+ is a good candidate for dosimetry in the range of 80 mGy-20 Gy. • PLUM can be potentially used for in vivo, in situ and quasi in real time dosimetry.

A solid-state dedicated circularly polarized luminescence spectrophotometer: Development and application.

Science.gov (United States)

Harada, Takunori; Hayakawa, Hiroshi; Watanabe, Masayuki; Takamoto, Makoto

2016-07-01

A new solid-state dedicated circularly polarized luminescence (CPL) instrument (CPL-200CD) was successfully developed for measuring true CPL spectra for optically anisotropic samples on the basis of the Stokes-Mueller matrix approach. Electric components newly installed in the CPL-200CD include a pulse motor-driven sample rotation holder and a 100 kHz lock-in amplifier to achieve the linearly polarized luminescence measurement, which is essential for obtaining the true CPL signal for optically anisotropic samples. An acquisition approach devised for solid-state CPL analysis reduces the measurement times for a data set by ca. 98% compared with the time required in our previous method. As a result, the developed approach is very effective for samples susceptible to light-induced degradation. The theory and implementation of the method are described, and examples of its application to a CPL sample with macroscopic anisotropies are provided. An important advantage of the developed instrument is its ability to obtain molecular information for both excited and ground states because circular dichroism measurements can be performed by switching the monochromatic light to white light without rearrangement of the sample.

Green and red luminescence in co-precipitation synthesized Pr:LuAG nanophosphor

Energy Technology Data Exchange (ETDEWEB)

Kumar, S. Arun; Kumar, K. Ashok; Gunaseelan, M.; Senthilselvan, J., E-mail: jsselvan@hotmail.com [Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai–600 025, Tamil Nadu (India); Asokan, K. [Materials Science Group, Inter University Accelerator Centre, New Delhi-110067 (India)

2016-05-06

Pr:LuAG nanophosphor is an effective candidate in magnetic resonance imaging coupled positron emission tomography (MRI-PET) for medical imaging and scintillator applications. LuAG:Pr (0.05, 0.15 mol%) nanoscale ceramic powders were synthesized by co-precipitation method using urea as precipitant. Effect of antisite defect on structure and luminescence behavior was investigated. Pr:LuAG nanoceramic powders are found crystallized in cubic structure by high temperature calcination at 1400 °C and it shows antisite defect. HR-SEM analysis revealed spherically shaped Pr:LuAG nanoceramic particulate powders with ∼100 nm size. By the excitation at 450 nm, Pr:LuAG nanophosphor exhibit green to red luminescence in the wavelength range of 520 to 680 nm, which is originated from multiplet transition of Pr{sup 3+} ions.

Redox-induced reversible luminescence switching of cerium-doped upconversion nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Huang, Yanan [College of Sciences, Shanghai University, Shanghai 200444 (China); International Laboratory for Adaptive Bio-nanotechnology, Suzhou Institute of Nano-tech and Nano-bionics (SINANO), Chinese Academy of Science, Suzhou 215123 (China); Xiao, Qingbo, E-mail: qbxiao2011@sinano.ac.cn [International Laboratory for Adaptive Bio-nanotechnology, Suzhou Institute of Nano-tech and Nano-bionics (SINANO), Chinese Academy of Science, Suzhou 215123 (China); Wang, Jian [College of Sciences, Shanghai University, Shanghai 200444 (China); International Laboratory for Adaptive Bio-nanotechnology, Suzhou Institute of Nano-tech and Nano-bionics (SINANO), Chinese Academy of Science, Suzhou 215123 (China); Xi, Yonglan [Laboratory for Agricultural Wastes Treatment and Recycling Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Science, Nanjing 210014 (China); Li, Fujin [International Laboratory for Adaptive Bio-nanotechnology, Suzhou Institute of Nano-tech and Nano-bionics (SINANO), Chinese Academy of Science, Suzhou 215123 (China); Feng, Yamin [College of Sciences, Shanghai University, Shanghai 200444 (China); International Laboratory for Adaptive Bio-nanotechnology, Suzhou Institute of Nano-tech and Nano-bionics (SINANO), Chinese Academy of Science, Suzhou 215123 (China); Shi, Liyi [College of Sciences, Shanghai University, Shanghai 200444 (China); Lin, Hongzhen, E-mail: hzlin2010@sinano.ac.cn [International Laboratory for Adaptive Bio-nanotechnology, Suzhou Institute of Nano-tech and Nano-bionics (SINANO), Chinese Academy of Science, Suzhou 215123 (China)

2016-05-15

Smart upconversion nanophosphors (UCNPs) that can be reversibly switched between two or more luminescent states by certain external stimuli have attracted considerable attention due to their great potential in biological applications. Here we report for the first time a type of redox-switchable UCNPs by codoping NaGdF{sub 4}:Yb/Er nanorods with the redox-active Ce{sup 3+}/Ce{sup 4+} ion pairs. A reversible switching of their UC luminescence intensity was observed upon the variation of the surrounding redox environments. We show solid proof that the luminescence switching is caused by the tailoring of the NaGdF{sub 4} host crystal structure in response to changing redox state of the codoped cerium ions. A proof-of-concept example is further demonstrated by using these UCNPs for probing the dynamical variation of redox environments in biological tissues. - Highlights: • Synthesis of upconversion nanoparticles doped with Ce{sup 3+}/Ce{sup 4+} ions. • The precise and reversible modification of crystal structure by redox reactions. • Tuning the upconversion luminescence by tailoring the crystal structure.

Mechanism of band-edge luminescence in cuprous iodide single crystals

International Nuclear Information System (INIS)

Gao, Pan; Gu, Mu; Liu, Xi; Liu, Bo; Zheng, Yan-Qing; Shi, Er-Wei; Shi, Jun-Yan; Zhang, Guo-bin

2014-01-01

Highlights: • The luminescence properties of CuI crystals are influenced by the quality of the as-grown crystals. • The emission peaks of free-exciton and bound-exciton are observed in the CuI single crystals. • The ultrafast component luminescence is warranted to the donor-acceptor pair recombination. • The exciton absorption and electron excitation multiplication processes were observed in CuI. - Abstract: The photoluminescence spectra of CuI crystals using synchrotron radiation as an excitation light source were obtained at 60 K. The emission peaks at 405, 415, 420 and 443 nm were observed. The possible origins of these peaks were discussed by the temperature dependence of luminescence spectra for CuI material. Meanwhile, the photoluminescence spectra of CuI powder with different excitation intensity were measured and the ultrafast luminescence component of CuI crystals was warranted to be attributed to the recombination of donor acceptor pair. Furthermore, the excitation process was studied by measuring the photoluminescence excitation spectra of CuI crystals and powder

Raman scattering and luminescence of high-Tc superconducting oxides

International Nuclear Information System (INIS)

Eremenko, V.V.; Gnezdilov, V.P.; Fomin, V.I.; Fugol', I.Ya.; Samovarov, V.N.

1989-01-01

Raman and luminescence spectra of high-T c superconducting oxides are summarized, mainly YBa 2 Cu 3 O 7-σ and partly La 2-x Ba x CuO 4-σ . In raman spectra we succeeded to distinguish electron scattering to define the energy gap Δ in the superconducting state. The luminescence spectra are due to the emission of oxygen and interaction with conduction electrons. 70 refs.; 13 figs

Luminescence properties of the Sm-doped borate glasses

Energy Technology Data Exchange (ETDEWEB)

Kindrat, I.I. [University of Zielona Góra, Institute of Physics, Division of Spectroscopy of Functional Materials, 4a Szafrana Street, 65-516 Zielona Góra (Poland); Padlyak, B.V., E-mail: B.Padlyak@if.uz.zgora.pl [University of Zielona Góra, Institute of Physics, Division of Spectroscopy of Functional Materials, 4a Szafrana Street, 65-516 Zielona Góra (Poland); Vlokh Institute of Physical Optics, 23 Dragomanov Street, 79-005 Lviv (Ukraine); Drzewiecki, A. [University of Zielona Góra, Institute of Physics, Division of Spectroscopy of Functional Materials, 4a Szafrana Street, 65-516 Zielona Góra (Poland)

2015-10-15

The optical absorption and photoluminescence (emission and excitation) spectra as well as decay kinetics of a series of the Sm-doped glasses with Li{sub 2}B{sub 4}O{sub 7}, LiKB{sub 4}O{sub 7}, CaB{sub 4}O{sub 7}, and LiCaBO{sub 3} compositions were investigated and analysed. The Li{sub 2}B{sub 4}O{sub 7}:Sm, LiKB{sub 4}O{sub 7}:Sm, CaB{sub 4}O{sub 7}:Sm, and LiCaBO{sub 3}:Sm glasses of high optical quality have been obtained from the corresponding polycrystalline compounds in the air atmosphere, using a standard glass technology. On the basis of electron paramagnetic resonance (EPR) and optical spectra analysis it was shown that the samarium impurity is incorporated into the glass network as Sm{sup 3+} (4f{sup 5}, {sup 6}H{sub 5/2}) ions, exclusively. All observed 4f – 4f transitions of the Sm{sup 3+} centres in the optical absorption and luminescence spectra of the investigated glasses are identified. Most intense emission band of the Sm{sup 3+} ions peaked about 598 nm ({sup 4}G{sub 5/2} → {sup 6}H{sub 7/2} transition) is characterised by a single exponential decay with typical lifetime values, which depend on the basic glass composition as well as concentration and local structure of the Sm{sup 3+} luminescence centres. The quantum efficiency has been evaluated for observed transitions of the Sm{sup 3+} centres using obtained experimental lifetimes and radiative lifetimes calculated by Judd–Ofelt theory. The calculated high quantum efficiencies and measured quantum yields of luminescence show that the investigated borate glasses are perspective luminescence materials. Energy transfer from the Ce{sup 3+} non-controlled impurity and intrinsic luminescence centres to the Sm{sup 3+} centres has been observed. Peculiarities of the Sm{sup 3+} local structure in the network of investigated glasses have been discussed based on the obtained spectroscopic results and structural data. - Highlights: • The Sm-doped Li{sub 2}B{sub 4}O{sub 7}, LiKB{sub 4}O{sub 7}, Ca

X-Ray Absorption Near-Edge Structure (XANES) of Calcium L3,2 Edges of Various Calcium Compounds and X-Ray Excited Optical Luminescence (XEOL) Studies of Luminescent Calcium Compounds

International Nuclear Information System (INIS)

Ko, J. Y. Peter; Zhou Xingtai; Sham, T.-K.; Heigl, Franziskus; Regier, Tom; Blyth, Robert

2007-01-01

X-ray absorption at calcium L3,2 edges of various calcium compounds were measured using a high resolution Spherical Grating Monochromator (SGM) at the Canadian Light Source (CLS). We observe that each compound has its unique fine structure of L3,2 edges. This uniqueness is due to differences in local structure of compounds. We also performed (X-ray Excited Optical Luminescence) XEOL of selected luminescent calcium compounds to investigate their optical properties. XEOL is a photon-in-photon-out technique in which the optical luminescence that is excited by tunable x-rays from a synchrotron light source is monitored. Depending on excitation energy of the x-ray, relative intensities of luminescence peaks vary. Recent findings of the results will be presented here

Luminescence and scintillation properties of LuPO4-Ce nanoparticles

International Nuclear Information System (INIS)

Vistovskyy, V.; Malyy, T.; Pushak, A.; Vas’kiv, A.; Shapoval, A.; Mitina, N.; Gektin, A.; Zaichenko, A.; Voloshinovskii, A.

2014-01-01

Study of the spectral-luminescence parameters of LuPO 4 -Ce nanoparticles upon the excitation by X-ray quanta and synchrotron radiation with photon energies of 4–25 eV was performed. Nanoparticles with mean size about a=35 nm and nanoparticles with size less than 12 nm reveal the different structures of cerium centers. Luminescence efficiency of LuPO 4 -Ce nanoparticles of a 4 -Ce nanoparticles studied using synchrotron and X-ray excitation. • Different structure of Ce 3+ -centers has been revealed for LuPO 4 -Ce nanoparticles. • Luminescence of LuPO 4 -Ce with size less than 12 nm is strongly quenched upon the X-ray excitation

STUDIES ON BIOLUMINESCENCE : XVII. FLUORESCENCE AND INHIBITION OF LUMINESCENCE IN CTENOPHORES BY ULTRA-VIOLET LIGHT.

Science.gov (United States)

Harvey, E N

1925-01-20

1. Small dumps of the luminous cells of Mnemiopsis cannot readily be stimulated mechanically but will luminesce on treatment with saponin solution. Larger groups of luminous cells (such as are connected with two paddle plates) luminesce on mechanical stimulation. This suggests that mechanical stimulation to luminesce occurs chiefly through a nerve mechanism which has been broken up in the small dumps of luminous tissue. 2. The smallest bits of luminous tissue, even cells freed from the animal by agitation, that will pass through filter paper, lose their power to luminesce in daylight and regain it (at least partially) in the dark. 3. Luminescence of the whole animal and of individual cells is suppressed by near ultra-violet light (without visible light). 4. Inhibition in ultra-violet light is not due to stimulation (by the ultra-violet light) of the animal to luminesce, thereby using up the store of photogenic material. 5. Animals stimulated mechanically several times and placed in ultra-violet light show a luminescence along the meridians in the same positions as the luminescence that appears on stimulation. This luminescence in the ultra-violet or "tonic luminescence," is not obtained with light adapted ctenophores and is interpreted to be a fluorescence of the product of oxidation of the photogenic material. 6. Marked fluorescence of the luminous organ of the glowworm (Photuris) and of the luminous slime of Chatopterus may be observed in ultra-violet but no marked fluorescence of the luminous substances of Cypridina is apparent. 7. Evidence is accumulating to show a close relation between fluorescent and chemiluminescent substances in animals, similar to that described for unsaturated silicon compounds and the Grignard reagents.

Delayed luminescence in a multiparameter approach to evaluation and reduction of radiobiological risks

Science.gov (United States)

Grasso, Rosaria; Cammarata, Francesco Paolo; Minafra, Luigi; Marchese, Valentina; Russo, Giorgio; Manti, Lorenzo; Musumeci, Francesco; Scordino, Agata

2017-07-01

In the framework of the research project ETHICS "Pre-clinical experimental and theoretical studies to improve treatment and protection by charged particles" funded by the National Nuclear Physics Institute, Italy, we studied the phenomenon called delayed luminescence emitted by non-tumorigenic breast epithelial MCF10A cell line after proton irradiation at different doses (0.5, 2, 6, 9 Gy). The aim is to found possible correlations between delayed luminescence and in vitro damaging induced by ion irradiation. The first results of this research show that the delayed luminescence kinetics is proton dose dependent. An interesting correlation between delayed luminescence and clonogenic potential was observed.

Afterglow luminescence in sol-gel/Pechini grown oxide materials: persistence or phosphorescence process? (Conference Presentation)

Science.gov (United States)

Sontakke, Atul; Ferrier, Alban; Viana, Bruno

2017-03-01

Persistent luminescence and phosphorescence, both yields afterglow luminescence, but are completely different mechanisms. Persistent luminescence involves a slow thermal release of trapped electrons stored in defect states, whereas the phosphorescence is caused due to triplet to singlet transition [1,2]. Many persistent luminescence phosphors are based on oxide inorganic hosts, and exhibit long afterglow luminescence after ceasing the excitation. We observed intense and long afterglow luminescence in sol-gel/pechini grown inorganic oxides, and as a first interpretation thought to be due to persistence mechanism. However, some of these materials do not exhibit defect trap centers, and a detailed investigation suggested it is due to phosphorescence, but not the persistence. Phosphorescence is not common in inorganic solids, and that too at room temperature, and therefore usually misinterpreted as persistence luminescence [3]. Here we present a detailed methodology to distinguish phosphorescence from persistence luminescence in inorganic solids, and the process to harvest highly efficient long phosphorescence afterglow at room temperature. 1. Jian Xu, Setsuhisa Tanabe, Atul D. Sontakke, Jumpei Ueda, Appl. Phys. Lett. 107, 081903 (2015) 2. Sebastian Reineke, Marc A. Baldo, Scientific Reports, 4, 3797 (2014) 3. Pengchong Xue, Panpan Wang, Peng Chen, Boqi Yao, Peng Gong, Jiabao Sun, Zhenqi Zhang, Ran Lu, Chem. Sci. (2016) DOI: 10.1039/C5SC03739E

Luminescent Metal Nanoclusters for Potential Chemosensor Applications

Directory of Open Access Journals (Sweden)

Muthaiah Shellaiah

2017-12-01

Full Text Available Studies of metal nanocluster (M-NCs-based sensors for specific analyte detection have achieved significant progress in recent decades. Ultra-small-size (<2 nm M-NCs consist of several to a few hundred metal atoms and exhibit extraordinary physical and chemical properties. Similar to organic molecules, M-NCs display absorption and emission properties via electronic transitions between energy levels upon interaction with light. As such, researchers tend to apply M-NCs in diverse fields, such as in chemosensors, biological imaging, catalysis, and environmental and electronic devices. Chemo- and bio-sensory uses have been extensively explored with luminescent NCs of Au, Ag, Cu, and Pt as potential sensory materials. Luminescent bi-metallic NCs, such as Au-Ag, Au-Cu, Au-Pd, and Au-Pt have also been used as probes in chemosensory investigations. Both metallic and bi-metallic NCs have been utilized to detect various analytes, such as metal ions, anions, biomolecules, proteins, acidity or alkalinity of a solution (pH, and nucleic acids, at diverse detection ranges and limits. In this review, we have summarized the chemosensory applications of luminescent M-NCs and bi-metallic NCs.

Efficient and thermally stable red luminescence from nano-sized phosphor of Gd{sub 6}MoO{sub 12}:Eu{sup 3+}

Energy Technology Data Exchange (ETDEWEB)

Qin, Lin [Soochow University, College of Chemistry, Chemical Engineering and Materials Science (China); Wei, Donglei [Pukyong National University, Department of Physics and Interdisciplinary Program of Biomedical Engineering (Korea, Republic of); Huang, Yanlin [Soochow University, College of Chemistry, Chemical Engineering and Materials Science (China); Kim, Sun Il [Pukyong National University, Department of Physics and Interdisciplinary Program of Biomedical Engineering (Korea, Republic of); Yu, Young Moon [Pukyong National University, LED-Marin Convergence Technology R and BD Center (Korea, Republic of); Seo, Hyo Jin, E-mail: hjseo@pknu.ac.kr [Pukyong National University, Department of Physics and Interdisciplinary Program of Biomedical Engineering (Korea, Republic of)

2013-09-15

A novel red-emitting nano-phosphor of Eu{sup 3+}-doped Gd{sub 6}MoO{sub 12} was successfully synthesized by the Pechini method. The crystalline phase was confirmed by X-ray powder diffraction analysis. The morphology of the nano-phosphor was analyzed by scanning electron microscopy, indicating a good crystallization with particles smaller than 500 nm. The luminescence properties such as photoluminescence spectra and decay curves were investigated. The phosphors can be efficiently excited by near-ultraviolet (near-UV) light and exhibit a bright red luminescence around 613 nm ascribed to the forced electric dipole transition {sup 5}D{sub 0}{yields}{sup 7}F{sub 2} of Eu{sup 3+} ions. The thermal stabilities were investigated from the temperature-dependent luminescence decay curves (lifetimes) and spectra intensities. The luminescence properties in relation to applications in white light-emitting diodes (W-LEDs) such as the absolute luminescence quantum efficiency, excitation wavelength, and color coordinates were discussed. The Gd{sub 6}MoO{sub 12}:Eu{sup 3+} nano-phosphor is a promising red-emitting candidate for the fabrication of W-LEDs with near-UV chips.

Development of an ultralow-light-level luminescence image analysis system for dynamic measurements of transcriptional activity in living and migrating cells.

Science.gov (United States)

Maire, E; Lelièvre, E; Brau, D; Lyons, A; Woodward, M; Fafeur, V; Vandenbunder, B

2000-04-10

We have developed an approach to study in single living epithelial cells both cell migration and transcriptional activation, which was evidenced by the detection of luminescence emission from cells transfected with luciferase reporter vectors. The image acquisition chain consists of an epifluorescence inverted microscope, connected to an ultralow-light-level photon-counting camera and an image-acquisition card associated to specialized image analysis software running on a PC computer. Using a simple method based on a thin calibrated light source, the image acquisition chain has been optimized following comparisons of the performance of microscopy objectives and photon-counting cameras designed to observe luminescence. This setup allows us to measure by image analysis the luminescent light emitted by individual cells stably expressing a luciferase reporter vector. The sensitivity of the camera was adjusted to a high value, which required the use of a segmentation algorithm to eliminate the background noise. Following mathematical morphology treatments, kinetic changes of luminescent sources were analyzed and then correlated with the distance and speed of migration. Our results highlight the usefulness of our image acquisition chain and mathematical morphology software to quantify the kinetics of luminescence changes in migrating cells.

Gamma-Ray Dosimetry System Using Radiation-Resistant Optical Fibers and a Luminescent Material

International Nuclear Information System (INIS)

Toh, K.; Nakamura, T.; Yamagishi, H.; Sakasai, K.; Soyama, K.; Shikama, T.; Nagata, S.

2013-06-01

Gamma-ray dosimetry system using radiation-resistant optical fibers and a luminescent material was developed for use in a damaged Fukushima Dai-ichi nuclear power plant. The system was designed to be compact and unnecessary of an external supply of electricity to a radiation sensor head with a contaminated working environment and restricted through-holes to a measurement point in the damaged reactor. The system can detect a gamma-ray dose rate at a measurement point using a couple of optical fibers and a luminescent material with a coincidence method. This system demonstrated a linear response with respect to the gamma-ray dose rate from 0.5 mGy/h to 0.1 Gy/h and the system had a capability to measure the dose rate of more than 10 2 Gy/h. (authors)

Luminescent Lanthanide Reporters for High-Sensitivity Novel Bioassays

Energy Technology Data Exchange (ETDEWEB)

Anstey, Mitchell R. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Fruetel, Julia A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Foster, Michael E. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Hayden, Carl C. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Buckley, Heather L. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Arnold, John [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

2013-09-01

Biological imaging and assay technologies rely on fluorescent organic dyes as reporters for a number of interesting targets and processes. However, limitations of organic dyes such as small Stokes shifts, spectral overlap of emission signals with native biological fluorescence background, and photobleaching have all inhibited the development of highly sensitive assays. To overcome the limitations of organic dyes for bioassays, we propose to develop lanthanide-based luminescent dyes and demonstrate them for molecular reporting applications. This relatively new family of dyes was selected for their attractive spectral and chemical properties. Luminescence is imparted by the lanthanide atom and allows for relatively simple chemical structures that can be tailored to the application. The photophysical properties offer unique features such as narrow and non-overlapping emission bands, long luminescent lifetimes, and long wavelength emission, which enable significant sensitivity improvements over organic dyes through spectral and temporal gating of the luminescent signal.Growth in this field has been hindered due to the necessary advanced synthetic chemistry techniques and access to experts in biological assay development. Our strategy for the development of a new lanthanide-based fluorescent reporter system is based on chelation of the lanthanide metal center using absorbing chromophores. Our first strategy involves "Click" chemistry to develop 3-fold symmetric chelators and the other involves use of a new class of tetrapyrrole ligands called corroles. This two-pronged approach is geared towards the optimization of chromophores to enhance light output.

Luminescent properties of Al2O3: Tb powders

International Nuclear Information System (INIS)

Esparza G, A.E.; Garcia, M.; Falcony, C.; Azorin N, J.

2000-01-01

In this work the photo luminescent and cathode luminescent characteristics of aluminium oxide (Al 2 O 3 ) powders impurified with terbium (Tb) were studied for their use in dosimetry. The optical, structural, morphological characteristics of the powders as function of variation in the impurity concentration and the annealing temperature will be presented. As regards the optical properties of powders (photoluminescence and cathode luminescence) it was observed a characteristic emission associated with radiative transitions between electron energy levels of terbium, the spectra associated with this emission consists of several peaks associated with such transitions. In the structural and morphological characterization (X-ray diffraction and scanning electron microscopy) it was appreciated that in accordance the annealing temperature of powders is augmented it is evident the apparition of certain crystalline phases. The results show that this is a promissory material for radiation dosimetry. (Author)

Fiber-coupled Luminescence Dosimetry in Therapeutic and Diagnostic Radiology

DEFF Research Database (Denmark)

Andersen, Claus Erik

2011-01-01

. Some crystalline phosphors, such as carbon-doped aluminium oxide (Al2O3:C) have the ability to store charge produced in the crystal during irradiation. The stored charge may later be released by fiber-guided laser light under emission of so-called optically stimulated luminescence (OSL). The OSL signal......Fiber-coupled luminescence dosimetry is an emerging technology with several potentially attractive features of relevance for uses in therapeutic and diagnostic radiology: direct water equivalence (i.e. no significant perturbation of the radiation field in a water phantom or a patient), sub......-mm detector size, high dynamic range (below a mGy to several Gy), microsecond time resolution, and absence of electrical wires or other electronics in the dosimeter probe head. Fiber-coupled luminescence dosimetry systems typically consist of one or more small samples of phosphor, e.g. a mg of plastic...

Spectroscopic and visible luminescence properties of rare earth ions in lead fluoroborate glasses