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Sample records for luminescence measurements showed

  1. 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.

  2. Time-resolved measurements of luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Collier, Bradley B. [Department of Biomedical Engineering, 408 Mechanical Engineering Office Building, Spence Street, Texas A and M University, College Station, TX 77843 (United States); McShane, Michael J., E-mail: mcshane@tamu.edu [Department of Biomedical Engineering, 408 Mechanical Engineering Office Building, Spence Street, Texas A and M University, College Station, TX 77843 (United States); Materials Science and Engineering Program, 408 Mechanical Engineering Office Building, Spence Street, Texas A and M University, College Station, TX 77843 (United States)

    2013-12-15

    Luminescence sensing and imaging has become more widespread in recent years in a variety of industries including the biomedical and environmental fields. Measurements of luminescence lifetime hold inherent advantages over intensity-based response measurements, and advances in both technology and methods have enabled their use in a broader spectrum of applications including real-time medical diagnostics. This review will focus on recent advances in analytical methods, particularly calculation techniques, including time- and frequency-domain lifetime approaches as well as other time-resolved measurements of luminescence. -- Highlights: • Developments in technology have led to widespread use of luminescence lifetime. • Growing interest for sensing and imaging applications. • Recent advances in approaches to lifetime calculations are reviewed. • Advantages and disadvantages of various methods are weighed. • Other methods for measurement of luminescence lifetime also described.

  3. Time-resolved measurements of luminescence

    International Nuclear Information System (INIS)

    Collier, Bradley B.; McShane, Michael J.

    2013-01-01

    Luminescence sensing and imaging has become more widespread in recent years in a variety of industries including the biomedical and environmental fields. Measurements of luminescence lifetime hold inherent advantages over intensity-based response measurements, and advances in both technology and methods have enabled their use in a broader spectrum of applications including real-time medical diagnostics. This review will focus on recent advances in analytical methods, particularly calculation techniques, including time- and frequency-domain lifetime approaches as well as other time-resolved measurements of luminescence. -- Highlights: • Developments in technology have led to widespread use of luminescence lifetime. • Growing interest for sensing and imaging applications. • Recent advances in approaches to lifetime calculations are reviewed. • Advantages and disadvantages of various methods are weighed. • Other methods for measurement of luminescence lifetime also described

  4. 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...

  5. Cherenkov luminescence measurements with digital silicon photomultipliers: a feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Ciarrocchi, Esther; Belcari, Nicola; Guerra, Alberto Del [Department of Physics, University of Pisa, Pisa (Italy); INFN, section of Pisa, Pisa (Italy); Cherry, Simon R. [Department of Biomedical Engineering, University of California, Davis, CA (United States); Lehnert, Adrienne; Hunter, William C. J.; McDougald, Wendy; Miyaoka, Robert S.; Kinahan, Paul E. [Department of Radiology, University of Washington, Seattle, WA (United States)

    2015-11-16

    A feasibility study was done to assess the capability of digital silicon photomultipliers to measure the Cherenkov luminescence emitted by a β source. Cherenkov luminescence imaging (CLI) is possible with a charge coupled device (CCD) based technology, but a stand-alone technique for quantitative activity measurements based on Cherenkov luminescence has not yet been developed. Silicon photomultipliers (SiPMs) are photon counting devices with a fast impulse response and can potentially be used to quantify β-emitting radiotracer distributions by CLI. In this study, a Philips digital photon counting (PDPC) silicon photomultiplier detector was evaluated for measuring Cherenkov luminescence. The PDPC detector is a matrix of avalanche photodiodes, which were read one at a time in a dark count map (DCM) measurement mode (much like a CCD). This reduces the device active area but allows the information from a single avalanche photodiode to be preserved, which is not possible with analog SiPMs. An algorithm to reject the noisiest photodiodes and to correct the measured count rate for the dark current was developed. The results show that, in DCM mode and at (10–13) °C, the PDPC has a dynamic response to different levels of Cherenkov luminescence emitted by a β source and transmitted through an opaque medium. This suggests the potential for this approach to provide quantitative activity measurements. Interestingly, the potential use of the PDPC in DCM mode for direct imaging of Cherenkov luminescence, as a opposed to a scalar measurement device, was also apparent. We showed that a PDPC tile in DCM mode is able to detect and image a β source through its Cherenkov radiation emission. The detector’s dynamic response to different levels of radiation suggests its potential quantitative capabilities, and the DCM mode allows imaging with a better spatial resolution than the conventional event-triggered mode. Finally, the same acquisition procedure and data processing could

  6. Cherenkov luminescence measurements with digital silicon photomultipliers: a feasibility study

    International Nuclear Information System (INIS)

    Ciarrocchi, Esther; Belcari, Nicola; Guerra, Alberto Del; Cherry, Simon R.; Lehnert, Adrienne; Hunter, William C. J.; McDougald, Wendy; Miyaoka, Robert S.; Kinahan, Paul E.

    2015-01-01

    A feasibility study was done to assess the capability of digital silicon photomultipliers to measure the Cherenkov luminescence emitted by a β source. Cherenkov luminescence imaging (CLI) is possible with a charge coupled device (CCD) based technology, but a stand-alone technique for quantitative activity measurements based on Cherenkov luminescence has not yet been developed. Silicon photomultipliers (SiPMs) are photon counting devices with a fast impulse response and can potentially be used to quantify β-emitting radiotracer distributions by CLI. In this study, a Philips digital photon counting (PDPC) silicon photomultiplier detector was evaluated for measuring Cherenkov luminescence. The PDPC detector is a matrix of avalanche photodiodes, which were read one at a time in a dark count map (DCM) measurement mode (much like a CCD). This reduces the device active area but allows the information from a single avalanche photodiode to be preserved, which is not possible with analog SiPMs. An algorithm to reject the noisiest photodiodes and to correct the measured count rate for the dark current was developed. The results show that, in DCM mode and at (10–13) °C, the PDPC has a dynamic response to different levels of Cherenkov luminescence emitted by a β source and transmitted through an opaque medium. This suggests the potential for this approach to provide quantitative activity measurements. Interestingly, the potential use of the PDPC in DCM mode for direct imaging of Cherenkov luminescence, as a opposed to a scalar measurement device, was also apparent. We showed that a PDPC tile in DCM mode is able to detect and image a β source through its Cherenkov radiation emission. The detector’s dynamic response to different levels of radiation suggests its potential quantitative capabilities, and the DCM mode allows imaging with a better spatial resolution than the conventional event-triggered mode. Finally, the same acquisition procedure and data processing could

  7. Measuring performance at trade shows

    DEFF Research Database (Denmark)

    Hansen, Kåre

    2004-01-01

    Trade shows is an increasingly important marketing activity to many companies, but current measures of trade show performance do not adequately capture dimensions important to exhibitors. Based on the marketing literature's outcome and behavior-based control system taxonomy, a model is built...... that captures a outcome-based sales dimension and four behavior-based dimensions (i.e. information-gathering, relationship building, image building, and motivation activities). A 16-item instrument is developed for assessing exhibitors perceptions of their trade show performance. The paper presents evidence...

  8. Pukaki 1-01 : initial luminescence dating and radiometric measurements

    International Nuclear Information System (INIS)

    Rieser, U.

    2001-01-01

    Core from Pukaki 1-01 was sampled for luminescence dating and radiometric measurements on 14 March 2001 in the dark room laboratory at Victoria University. Seven samples were taken to get an overview of the crater history, and laboratory work was completed in August 2001. (author). 2 figs., 3 tabs

  9. 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

  10. 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.

  11. 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

  12. Luminescent two-color tracer particles for simultaneous velocity and temperature measurements in microfluidics

    International Nuclear Information System (INIS)

    Massing, J; Kähler, C J; Cierpka, C; Kaden, D

    2016-01-01

    The simultaneous and non-intrusive measurement of temperature and velocity fields in flows is of great scientific and technological interest. To sample the velocity and temperature, tracer particle based approaches have been developed, where the velocity is measured using PIV or PTV and the temperature is obtained from the intensity (LIF, thermographic phosphors) or frequency (TLC) of the light emitted or reflected by the tracer particles. In this article, a measurement technique is introduced, that relates the luminescent intensity ratio of individual dual-color luminescent tracer particles to temperature. Different processing algorithms are tested on synthetic particle images and compared with respect to their accuracy in estimating the intensity ratio. Furthermore, polymer particles which are doped with the temperature sensitive dye europium (III) thenoyltrifluoroacetonate (EuTTA) and the nearly temperature insensitive reference dye perylene are characterized as valid tracers. The results show a reduction of the temperature measurement uncertainty of almost 40% (95% confidence interval) compared to previously reported luminescent particle based measurement techniques for microfluidics. (paper)

  13. Effect of luminescence transport through adipose tissue on measurement of tissue temperature by using ZnCdS nanothermometers

    Science.gov (United States)

    Volkova, Elena K.; Yanina, Irina Yu.; Sagaydachnaya, Elena; Konyukhova, Julia G.; Kochubey, Vyacheslav I.; Tuchin, Valery V.

    2018-02-01

    The spectra of luminescence of ZnCdS nanoparticles (ZnCdS NPs) were measured and analyzed in a wide temperature range: from room to human body and further to a hyperthermic temperature resulting in tissue morphology change. The results show that the signal of luminescence of ZnCdS NPs placed within the tissue is reasonably good sensitive to temperature change and accompanied by phase transitions of lipid structures of adipose tissue. It is shown that the presence of a phase transition in adipose tissue upon its heating (polymorphic transformations of lipids) leads to a nonmonotonic temperature dependence of the intensity of luminescence for the nanoparticles introduced into adipose tissue. This is due to a change in the light scattering by the tissue. The light scattering of adipose tissue greatly distorts the results of temperature measurements. The application of these nanoparticles is possible for temperature measurements in very thin or weakly scattering samples.

  14. Study of carrier concentration in single InP nanowires by luminescence and Hall measurements

    International Nuclear Information System (INIS)

    Lindgren, David; Hultin, Olof; Heurlin, Magnus; Storm, Kristian; Borgström, Magnus T; Samuelson, Lars; Gustafsson, Anders

    2015-01-01

    The free electron carrier concentrations in single InP core–shell nanowires are determined by micro-photoluminescence, cathodoluminescence (CL) and Hall effect measurements. The results from luminescence measurements were obtained by solving the Fermi–Dirac integral, as well as by analyzing the peak full width at half maximum (FWHM). Furthermore, the platform used for Hall effect measurements, combined with spot mode CL spectroscopy, is used to determine the carrier concentrations at specific positions along single nanowires. The results obtained via luminescence measurements provide an accurate and rapid feedback technique for the epitaxial development of doping incorporation in nanowires. The technique has been employed on several series of samples in which growth parameters, such as V/III-ratio, temperature and dopant flows, were investigated in an optimization procedure. The correlation between the Hall effect and luminescence measurements for extracting the carrier concentration of different samples were in excellent agreement. (paper)

  15. 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.

  16. A high sensitivity optically stimulated luminescence scanning system for measurement of single sand-sized grains

    DEFF Research Database (Denmark)

    Duller, G.A.T.; Bøtter-Jensen, L.; Kohsiek, P.

    1999-01-01

    An instrument has been designed for the routine analysis of the optically stimulated luminescence signal from single grains of sand. The system is capable of analysing over 3000 individual grains in a single measurement sequence, and the OSL signal from each grain can be read in less than 3 s....... The design principles are described, along with preliminary measurements that illustrate the operation of the system and its capabilities....

  17. 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)

  18. 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

  19. Identification of irradiated spices with luminescence measurements: a European intercomparison

    Energy Technology Data Exchange (ETDEWEB)

    Heide, L; Guggenberger, R; Boegl, K W [Federal Health Office, Neuherberg/Muenchen (Germany, F.R.). Inst. for Radiation Hygiene

    1989-01-01

    Blind tests were performed measuring the thermoluminescence intensity on samples from 10 different spices that were either irradiated or unirradiated. The chemiluminescence was measured on 10 additional spice samples. Twelve institutions participated in this collaborative study. Thresholds were defined which, when exceeded, declare samples as irradiated. The recovering rate was nearly 100% for samples investigated by thermoluminescence. Only one out of 495 irradiated samples was not identified. By using chemiluminescence, the participants succeeded in identifying 99% of unirradiated samples and 75% of irradiated samples from a total of 490 samples. (author).

  20. Measuring thermo-luminescence efficiency of TLD-2000 detectors to different energy photons

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Wei Min; Chen, Bao Wei; Han, Yi; Yang, Zhong Jian [China Institute for Radiation Protection, Taiyuan (China)

    2016-06-15

    As an important detecting device, TLD is a widely used in the radiation monitoring. It is essential for us to study the property of detecting element. The aim of this study is to calculate the thermo-luminescence efficiency of TL elements. A batch of thermo-luminescence elements were irradiated by the filtered X-ray beams of average energies in the range 40-200 kVp, 662 keV {sup 137}Cs gamma rays and then the amounts of lights were measured by the TL reader. The deposition energies in elements were calculated by theory formula and Monte Carlo simulation. The unit absorbed dose in elements by photons with different energies corresponding to the amounts of lights was calculated, which is called the thermo luminescent efficiency (η(E)). Because of the amounts of lights can be calculated by the absorbed dose in elements multiply η(E), the η(E) can be calculated by the experimental data (the amounts of lights) divided by absorbed dose. The deviation of simulation results compared with theoretical calculation results were less than 5%, so the absorbed dose in elements was calculated by simulation results in here. The change range of η(E) value, relative to 662 keV {sup 137}Cs gamma rays, is about 30% in the energy range of 33 keV to 662 keV, is in accordance by the comparison with relevant foreign literatures. The η(E) values can be used for updating the amounts of lights that are got by the direct ratio assumed relations with deposition energy in TL elements, which can largely reduce the error of calculation results of the amounts of lights. These data can be used for the design of individual dosimeter which used TLD-2000 thermo-luminescence elements, also have a certain reference value for manufacturer to improve the energy-response performance of TL elements by formulation adjustment.

  1. Evaluation of external exposures of the population of Ozyorsk, Russia, with luminescence measurements of bricks.

    Science.gov (United States)

    Woda, Clemens; Jacob, P; Ulanovsky, A; Fiedler, I; Mokrov, Y; Rovny, S

    2009-11-01

    Recently discovered historical documents indicate that large releases of noble gases (mainly (41)Ar and radioactive isotopes of Kr and Xe) from the Mayak Production Association (MPA) over the period from 1948 to 1956 may have caused considerable external exposures of both, inhabitants of Ozyorsk and former inhabitants of villages at the upper Techa River. To quantify this exposure, seven brick samples from three buildings in Ozyorsk, located 8-10 km north-northwest from the radioactive gas release points, were taken. The absorbed dose in brick was measured in a depth interval of 3-13 mm below the exposed surface of the bricks by means of the thermoluminescence (TL) and the optically stimulated luminescence (OSL) method. Generally, luminescence properties using TL were more favorable for precise dose determination than using OSL, but within their uncertainties the results from both methods agree well with each other. The absorbed dose due to natural radiation was assessed and subtracted under the assumption of the bricks to be completely dry. The weighted average of the anthropogenic dose for all samples measured by TL and OSL is 10 +/- 9 and 1 +/- 9 mGy, respectively. An upper limit for a possible anthropogenic dose in brick that would not be detected due to the measurement uncertainties is estimated at 24 mGy. This corresponds to an effective dose of about 21 mSv. A similar range of values is obtained in recently published dispersion calculations that were based on reconstructed MPA releases. It is concluded that the release of radioactive noble gases from the radiochemical and reactor plants at Mayak PA did not lead to a significant external exposure of the population of Ozyorsk. In addition, the study demonstrates the detection limit for anthropogenic doses in ca. 60-year-old bricks to be about 24 mGy, if luminescence methods are used.

  2. Laser-induced luminescence lifetime measurement as an analytical probe for speciation of poly carboxylates in aqueous solutions

    International Nuclear Information System (INIS)

    Yoshio Takahashi; Takaumi Kimura; Yoshiharu Kato; Yoshitaka Minai

    2001-01-01

    Luminescence from lanthanide or actinide ion is influenced by hydration structure of the ion in aqueous solution system. In particular lifetime of the luminescence has been regarded as a measure of hydration number of the lanthanide or the actinide ion based on the studies on lifetime measurement of the ion in solid and solution system. Compared with other technique like NMR to determine the hydration number, laser induced lifetime measurement is advantageous in sensitivity and selectivity. This allows us to apply this method to determining the hydration number of lanthanide or actinide ion even at low concentration. (authors)

  3. First experience with a novel luminescence-based optical sensor for measurement of oxygenation in tumors

    International Nuclear Information System (INIS)

    Jarm, T.; Miklavcic, D.; Lesnicar, H.; Sersa, G.

    2001-01-01

    Background. The purpose of this preliminary study was to evaluate a novel luminescence-based fiber-optic sensor (OxyLite system) for the measurement of partial pressure of oxygen (pO 2 ) in tumors and for the detection of changes in pO 2 as a function of time. The new method was used simultaneously with the laser Doppler flowmetry method for the measurement of relative tissue perfusion. Materials and methods. Blood perfusion and pO 2 were measured continuously via fiber-optic sensors inserted into SA-1 tumors in anesthetized A/J mice. The changes in blood flow and oxygenation of tumors were induced by transient changes of the parameters of anesthesia and by injection of a vasoactive drug hydralazine. Results. Both optical methods used in the study successfully detected the induced changes in blood flow and pO 2 . The measurements of pO 2 were well correlated with measurements of microcirculatory blood perfusion. In the majority of pO 2 measurements, we observed an unexpected behavior of the signal during the stabilization process immediately after the insertion of the probe into tumor. This behaviour of the pO 2 signal was most probably caused by local tissue damage induced by the insertion of the probe. Conclusion. The novel luminescence-based optical oximetry can reliably detect local pO 2 changes in tumors as a function of time but some aspects of prolonged pO 2 measurement by this method require further investigation. (author)

  4. A study on the real-time radiation dosimetry measurement system based on optically stimulated luminescence

    International Nuclear Information System (INIS)

    Liu Yanping; Du Yanzhao; Chen Zhaoyang; Ba Weizhen; Fan Yanwei; Pan Shilie; Guo Qi

    2008-01-01

    The optically stimulated luminescent (OSL) radiation dosimeter technically surveys a wide dynamic measurement range and a high sensitivity. Optical fiber dosimeters provide capability for remote monitoring of the radiation in the locations which are difficult-to-access and hazardous. In addition, optical fiber dosimeters are immune to electrical and radio-frequency interference. In this paper, a novel remote optical fiber radiation dosimeter is described. The optical fiber dosimeter takes advantage of the charge trapping materials CaS:Ce, Sm that exhibit OSL. The measuring range of the dosimeter is from 0.1 to 100 Gy. The equipment is relatively simple and small in size, and has low power consumption. This device is suitable for measuring the space radiation dose and also can be used in high radiation dose condition and other dangerous radiation occasions. (authors)

  5. Time-resolved luminescence measurements of the magnetic field effect on paramagnetic photosensitizers in photodynamic reactions

    Science.gov (United States)

    Mermut, O.; Bouchard, J.-P.; Cormier, J.-F.; Desroches, P.; Diamond, K. R.; Fortin, M.; Gallant, P.; Leclair, S.; Marois, J.-S.; Noiseux, I.; Morin, J.-F.; Patterson, M. S.; Vernon, M.

    2008-02-01

    The development of multimodal molecular probes and photosensitizing agents for use in photodynamic therapy (PDT) is vital for optimizing and monitoring cytotoxic responses. We propose a combinatorial approach utilizing photosensitizing molecules that are both paramagnetic and luminescent with multimodal functionality to perturb, control, and monitor molecular-scale reaction pathways in PDT. To this end, a time-domain single photon counting lifetime apparatus with a 400 nm excitation source has been developed and integrated with a variable low field magnet (0- 350mT). The luminescence lifetime decay function was measured in the presence of a sweeping magnetic field for a custom designed photosensitizing molecule in which photoinduced electron transfer was studied The photosensitizer studied was a donor-acceptor complex synthesized using a porphyrin linked to a fullerene molecule. The magneto-optic properties were investigated for the free-base photosensitizer complex as well as those containing either diamagnetic (paired electron) or paramagnetic (unpaired electron) metal centers, Zn(II) and Cu(II). The magnetic field was employed to affect and modify the spin states of radical pairs of the photosensitizing agents via magnetically induced hyperfine and Zeeman effects. Since the Type 1 reaction pathway of an excited triplet state photosensitizer involves the production of radical species, lifetime measurements were conducted at low dissolved oxygen concentration (0.01ppm) to elucidate the dependence of the magnetic perturbation on the photosensitization mechanistic pathway. To optimize the magnetic response, a solvent study was performed examining the dependence of the emission properties on the magnetic field in solutions of varying dielectric constants. Lastly, the cytotoxicity in murine tumor cell suspensions was investigated for the novel porphyrin-fullerene complex by inducing photodynamic treatments and determining the associated cell survival.

  6. Measuring political polarization: Twitter shows the two sides of Venezuela

    Science.gov (United States)

    Morales, A. J.; Borondo, J.; Losada, J. C.; Benito, R. M.

    2015-03-01

    We say that a population is perfectly polarized when divided in two groups of the same size and opposite opinions. In this paper, we propose a methodology to study and measure the emergence of polarization from social interactions. We begin by proposing a model to estimate opinions in which a minority of influential individuals propagate their opinions through a social network. The result of the model is an opinion probability density function. Next, we propose an index to quantify the extent to which the resulting distribution is polarized. Finally, we apply the proposed methodology to a Twitter conversation about the late Venezuelan president, Hugo Chávez, finding a good agreement between our results and offline data. Hence, we show that our methodology can detect different degrees of polarization, depending on the structure of the network.

  7. Design of Interrogation Protocols for Radiation Dose Measurements Using Optically-Stimulated Luminescent Dosimeters.

    Science.gov (United States)

    Abraham, Sara A; Kearfott, Kimberlee J; Jawad, Ali H; Boria, Andrew J; Buth, Tobias J; Dawson, Alexander S; Eng, Sheldon C; Frank, Samuel J; Green, Crystal A; Jacobs, Mitchell L; Liu, Kevin; Miklos, Joseph A; Nguyen, Hien; Rafique, Muhammad; Rucinski, Blake D; Smith, Travis; Tan, Yanliang

    2017-03-01

    Optically-stimulated luminescent dosimeters are capable of being interrogated multiple times post-irradiation. Each interrogation removes a fraction of the signal stored within the optically-stimulated luminescent dosimeter. This signal loss must be corrected to avoid systematic errors in estimating the average signal of a series of optically-stimulated luminescent dosimeter interrogations and requires a minimum number of consecutive readings to determine an average signal that is within a desired accuracy of the true signal with a desired statistical confidence. This paper establishes a technical basis for determining the required number of readings for a particular application of these dosimeters when using certain OSL dosimetry systems.

  8. Optically stimulated luminescence from quartz measured using the linear modulation technique

    DEFF Research Database (Denmark)

    Bulur, E.; Bøtter-Jensen, L.; Murray, A.S.

    2000-01-01

    The optically stimulated luminescence (OSL) from heated natural quartz has been investigated using the linear modulation technique (LMT), in which the excitation light intensity is increased linearly during stimulation. In contrast to conventional stimulation, which usually produces a monotonical...

  9. CMOS direct time interval measurement of long-lived luminescence lifetimes.

    Science.gov (United States)

    Yao, Lei; Yung, Ka Yi; Cheung, Maurice C; Chodavarapu, Vamsy P; Bright, Frank V

    2011-01-01

    We describe a Complementary Metal-Oxide Semiconductor (CMOS) Direct Time Interval Measurement (DTIM) Integrated Circuit (IC) to detect the decay (fall) time of the luminescence emission when analyte-sensitive luminophores are excited with an optical pulse. The CMOS DTIM IC includes 14 × 14 phototransistor array, transimpedance amplifier, regulated gain amplifier, fall time detector, and time-to-digital convertor. We examined the DTIM system to measure the emission lifetime of oxygen-sensitive luminophores tris(4,7-diphenyl-1, 10-phenanthroline) ruthenium(II) ([Ru(dpp)(3)](2+)) encapsulated in sol-gel derived xerogel thin-films. The DTIM system fabricated using TSMC 0.35 μm process functions to detect lifetimes from 4 μs to 14.4 μs but can be tuned to detect longer lifetimes. The system provides 8-bit digital output proportional to lifetimes and consumes 4.5 mW of power with 3.3 V DC supply. The CMOS system provides a useful platform for the development of reliable, robust, and miniaturized optical chemical sensors.

  10. Luminescent Measurement Systems for the Investigation of a Scramjet Inlet-Isolator

    Directory of Open Access Journals (Sweden)

    Azam Che Idris

    2014-04-01

    Full Text Available Scramjets have become a main focus of study for many researchers, due to their application as propulsive devices in hypersonic flight. This entails a detailed understanding of the fluid mechanics involved to be able to design and operate these engines with maximum efficiency even at their off-design conditions. It is the objective of the present cold-flow investigation to study and analyse experimentally the mechanics of the fluid structures encountered within a generic scramjet inlet at M = 5. Traditionally, researchers have to rely on stream-thrust analysis, which requires the complex setup of a mass flow meter, a force balance and a heat transducer in order to measure inlet-isolator performance. Alternatively, the pitot rake could be positioned at inlet-isolator exit plane, but this method is intrusive to the flow, and the number of pitot tubes is limited by the model size constraint. Thus, this urgent need for a better flow diagnostics method is addressed in this paper. Pressure-sensitive paint (PSP has been applied to investigate the flow characteristics on the compression ramp, isolator surface and isolator sidewall. Numerous shock-shock interactions, corner and shoulder separation regions, as well as shock trains were captured by the luminescent system. The performance of the scramjet inlet-isolator has been shown to improve when operated in a modest angle of attack.

  11. Optically stimulated luminescence from quartz measured using the linear modulation technique

    International Nuclear Information System (INIS)

    Bulur, E.; Boetter-Jensen, L.; Murray, A.S.

    2000-01-01

    The optically stimulated luminescence (OSL) from heated natural quartz has been investigated using the linear modulation technique (LMT), in which the excitation light intensity is increased linearly during stimulation. In contrast to conventional stimulation, which usually produces a monotonically decreasing signal, linearly increasing the stimulation power gives peaks in the signal as a function of time. In cases where the OSL signal contains more than one component, the linear increase in power of the stimulation light may result in a curve containing overlapping peaks, where the most easily stimulated component occurs at a shorter time. This allows the separation of the overlapping OSL components, which are assumed to originate from different traps. The LM-OSL curve from quartz shows an initial peak followed by a broad one. Deconvolution using curve fitting has shown that the composite OSL curve from quartz can be approximated well by using a linear combination of first-order peaks. In addition to the three known components, i.e. fast, medium and slow components from continuous-wave-OSL studies, an additional slow component is also identified for the first time. The dose responses and thermal stabilities of the various components are also studied

  12. Influence of pulse-height discrimination threshold for photon counting on the accuracy of singlet oxygen luminescence measurement

    International Nuclear Information System (INIS)

    Lin, Huiyun; Chen, Defu; Wang, Min; Lin, Juqiang; Li, Buhong; Xie, Shusen

    2011-01-01

    Direct measurement of near-infrared (NIR) luminescence around 1270 nm is the golden standard of singlet oxygen ( 1 O 2 ) identification. In this study, the influence of pulse-height discrimination threshold on measurement accuracy of the 1 O 2 luminescence that is generated from the photoirradiation of meso-tetra (N-methyl-4-pyridyl) morphine tetra-tosylate (TMPyP) in aqueous solution was investigated by using our custom-developed detection system. Our results indicate that the discrimination threshold has a significant influence on the absolute 1 O 2 luminescence counts, and the optimal threshold for our detection system is found to be about − 41.2 mV for signal discrimination. After optimization, the derived triplet-state and 1 O 2 lifetimes of TMPyP in aqueous solution are found to be 1.73 ± 0.03 and 3.70 ± 0.04 µs, respectively, and the accuracy of measurement was further independently demonstrated using the laser flash photolysis technique

  13. Laser-Excited Luminescent Tracers for Planar Concentration Measurements in Gaseous Jets

    Science.gov (United States)

    Lozano, Antonio

    Tracers currently used in planar laser-induced fluorescence concentration measurements are not ideal for some experimental conditions, e.g., non-reacting turbulent gaseous flows at standard temperature and pressure. In this work, a number of chemicals have been evaluated, through consideration of their physical and photophysical properties, for use as luminescent concentration markers in turbulent gaseous flows. Two selected substances, biacetyl and acetone, have been studied in more detail. Acetone PLIF concentration images have been acquired in a non-reacting air jet, and the results have been compared to similar images obtained seeding with biacetyl. Acetone has proven to be a superior tracer when imaging fluorescence emission. Acetone has also been used as a fuel marker in hydrogen and methane diffusion flames. This single -laser technique enables simultaneous recording of the acetone and OH fluorescence emissions, as well as Mie scattering from ambient air dust particles. Acetone-sensitized, collisionally-induced biacetyl phosphorescence has been used to visualize molecular mixing in gaseous flows. Initial attempts to produce quantitative results with this method through simultaneous imaging of acetone fluorescence and collisionally-induced biacetyl emission, are described. Using laser-induced biacetyl phosphorescence imaging, a data set of cross-cut concentration images has been acquired in a nitrogen coflowing jet (Re = 5,000). The images have been statistically analyzed. Very simple models of the instantaneous concentration profile have been compared to the experimental data. Of all the tested models, a paraboloid has resulted to be the best approximation to the instantaneous 2-D profile. Finally, an experiment to study jet mixing in crossflow using acetone PLIF imaging has been designed. The flow facility has been constructed, and preliminary images obtained with a high quantum efficiency, thinned CCD detector have revealed the presence of jet structures

  14. Measured efficiency of a luminescent solar concentrator PV module called Leaf Roof

    NARCIS (Netherlands)

    Reinders, Angèle H.M.E; Debije, Michael G.; Rosemann, Alexander

    2017-01-01

    A functional prototype of a luminescent solar concentrator photovoltaic (LSC PV) module, called Leaf Roof, aims at demonstrating the design features of LSC PV technologies such as coloring, transparency, and flexibility in physical shape. In this paper, the prototype is presented and the first

  15. 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...

  16. Measurement of Solid-State Optical Refrigeration by Two-Band Differential Luminescence Thermometry

    Science.gov (United States)

    2010-03-01

    high speed transimpedance amplifier that generates an output voltage proportional to the difference in the optical power in bands A and D, i.e., IA...bands in the luminescence spectrum by inter- ference filters, in combination with large core optical fi- bers and highly amplified balanced

  17. 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.

  18. Combining infrared- and green-laser stimulation sources in single-grain luminescence measurements of feldspar and quartz

    DEFF Research Database (Denmark)

    Duller, G.A.T.; Bøtter-Jensen, L.; Murray, A.S.

    2003-01-01

    A system designed for measurement of the optically stimulated luminescence (OSL) from individual sand-sized mineral grains has been constructed. Previously, this system was equipped only with a green laser emitting at 532 run, but now an infrared (IR) laser at 830 run has been added. It is now...... possible to interchangeably use the two laser sources for optical stimulation. This is especially valuable for the measurement of feldspars. The power density using the IR laser at the grain is similar to500 W cm(-2), and stimulation for 1 s reduces the OSL signal to near background level. Initial results...

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. A new flexible system for measuring thermally and optically stimulated luminescence

    DEFF Research Database (Denmark)

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

    1997-01-01

    . New hardware features include a two-speed sample turntable, a new detachable beta irradiator with a Be window vacuum interface and the incorporation of an on-board minicomputer.,A completely new software concept was developed that allows the user unlimited control of the reader and has, at the same......The automated Riso TL/OSL reader system is used worldwide for luminescence dating, retrospective dosimetry environmental dosimetry and material characterization. In response to requests from many users we have re-designed the reader by incorporating a variety of new hardware and software features...

  6. 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...

  7. 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.

  8. 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

  9. Cyberknife Relative Output Factor measurements using fiber-coupled luminescence, MOSFETS and RADPOS dosimetry system

    DEFF Research Database (Denmark)

    Ploquin, N.; Kertzscher Schwencke, Gustavo Adolfo Vladimir; Vandervoort, E.

    2012-01-01

    from 5 to 60 mm. ROFs were also measured using a mobileMOSFET system (Best Medical Canada) and EBT1 and EBT2 GAFCHROMIC® (ISP, Ashland) radiochromic films. For cone sizes 12.5–60 mm all detector results were in agreement within the measurement uncertainty. The microMOSFET/RADPOS measurements (published.......3% and 0.865 ± 0.3% for 5, 7.5 and 10 mm cones. Our study shows that the microMOSFET/RADPOS and optical fiber‐coupled RL dosimetry system are well suited for Cyberknife cone output factors measurements over the entire range of field sizes, provided that appropriate correction factors are applied...

  10. 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

  11. 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.

  12. 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

  13. Global Skin-Friction Measurements Using Particle Image Surface FLow Visualization and a Luminescent Oil-Film

    Science.gov (United States)

    Husen, Nicholas; Roozeboom, Nettie; Liu, Tianshu; Sullivan, John P.

    2015-01-01

    A quantitative global skin-friction measurement technique is proposed. An oil-film is doped with a luminescent molecule and thereby made to fluoresce in order to resolve oil-film thickness, and Particle Image Surface Flow Visualization is used to resolve the velocity field of the surface of the oil-film. Skin-friction is then calculated at location x as (x )xh, where x is the displacement of the surface of the oil-film and is the dynamic viscosity of the oil. The data collection procedure and data analysis procedures are explained, and preliminary experimental skin-friction results for flow over the wing of the CRM are presented.

  14. A polymeric dosimeter film based on optically-stimulated luminescence for dose measurements below 1 kGy

    International Nuclear Information System (INIS)

    Kovacs, A.; Baranyai, M.; Wojnarovits, L.; Slezsak, I.; McLaughlin, W.L.; Miller, S.D.; Miller, A.; Fuochi, P.G.; Lavalle, M.

    1999-01-01

    A new potential dosimetry system 'Sunna' containing a microcrystalline dispersion of an optically-stimulated fluor in a plastic matrix has been recently developed to measure and image high doses. Our previous investigations have revealed that the new dosimeter system is capable of measuring absorbed doses in the dose range of 1-100 kGy. The optically-stimulated luminescence (OSL) analysis is based on the blue light stimulation of the colour center states produced upon irradiation, and the intensity of the resulting red-light emission is used to measure absorbed dose. This analysis is carried out with a simple table-top fluorimeter developed for this purpose having also the ability to calculate the mathematical formula of the calibration function. The Sunna dosimeter was recently investigated for potential use in lower dose range below 1 kGy. These investigations have shown that the film is suitable for measuring doses in the range of 1-1000 Gy for both electron and gamma radiation. To test the applicability of the film, its reproducibility, stability, sensitivity to ambient and UV light and irradiation temperature were measured. The stability of the dosimeter was investigated by monitoring the change of the OSL signal with storage time after irradiation. Further experiments proved the homogeneity of the film with respect to thickness variation, and limited differences in its response were found between batches. (author)

  15. Sizes of water-soluble luminescent quantum dots measured by fluorescence correlation spectroscopy

    International Nuclear Information System (INIS)

    Zhang Pudun; Li Liang; Dong Chaoqing; Qian Huifeng; Ren Jicun

    2005-01-01

    In this paper, fluorescence correlation spectroscopy (FCS) was applied to measure the size of water-soluble quantum dots (QDs). The measurements were performed on a home-built FCS system based on the Stokes-Einstein equation. The obtained results showed that for bare CdTe QDs the sizes from FCS were larger than the ones from transmission electron microscopy (TEM). The brightness of QDs was also evaluated using FCS technique. It was found that the stability of the surface chemistry of QDs would be significantly improved by capping it with hard-core shell. Our data demonstrated that FCS is a simple, fast, and effective method for characterizing the fluorescent quantum dots, and is especially suitable for determining the fluorescent nanoparticles less than 10 nm in water solution

  16. 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.

  17. 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) ...

  18. Radiation dose measurements of an on-board imager X-ray unit using optically-stimulated luminescence dosimeters

    International Nuclear Information System (INIS)

    Smith, Leon; Haque, Mamoon; Hill, Robin; Morales, Johnny

    2015-01-01

    Cone beam computed tomography (CBCT) is now widely used to image radiotherapy patients prior to treatment for the purpose of accurate patient setup. However each CBCT image delivered to a patient increases the total radiation dose that they receive. The measurement of the dose delivered from the CBCT images is not readily performed in the clinic. In this study, we have used commercially available optically stimulated luminescence (OSLD) dosimeters to measure the dose delivered by the Varian OBI on a radiotherapy linear accelerator. Calibration of the OSLDs was achieved by using a therapeutic X-ray unit. The dose delivered by a head CBCT scan was found to be 3.2 ± 0.3 mGy which is similar in magnitude to the dose of a head computed tomography (CT) scan. The results of this study suggest that the radiation hazard associated with CBCT is of a similar nature to that of conventional CT scans. We have also demonstrated that the OSLDs are suitable for these low X-ray dose measurements.

  19. 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.

  20. Studies on the profile measurement of hadron beams by means of residual-gas luminescence and ionization

    International Nuclear Information System (INIS)

    Boehme, Christian Gerhard Heinrich

    2011-01-01

    Modern particle accelerators are applied for a long time no more only in the fundamental physical research but in ever larger extent also in the concrete application for instance in the tumor irradiation or the microprocessor fabrication. The precise knowledge of the beam profile is thereby of great importance for the success. But in intermediate-energy hadron accelerators it hitherto not satisfyingly succeeds to measure the beam profiles not disturbingly. These study presents two not beam-disturbing measuring methods, which are based on the ion beam-residual gas interactions of luminescence and ionization. They were developed for different framework conditions at the JESSICA beam place of the COSY accelerator of the Juelich research center, an advance experiment of the planned European Spallation Source (ESS), as well at the proton synchrotron COSY itself, and the iThemba Laboratory for Accelerator Based Science, Somerset West, South Africa. Thereby the studies consider a large range of possible configuration parameters: Particle momenta from 3 MeV/c to 3 GeV/c, pressures from 1 mbar to 10 -11 mbar and time structures from DC beam to beam bunches of 100 ns length. The experimental arrangement, the application ranges, and the advantages and disadvantages of both methods are explained in this book.

  1. Chemical luminescence measurement of singlet oxygen generated by photodynamic therapy in solutions in real time

    Science.gov (United States)

    Luo, Shiming; Xing, Da; Zhou, Jing; Qin, Yanfang; Chen, Qun

    2005-04-01

    Photodynamic therapy (PDT) is a cancer therapy that utilizes optical energy to activate a photosensitizer drug in a target tissue. Reactive oxygen species (ROS), such as 1O2 and superoxide, are believed to be the major cytotoxic agents involved in PDT. Although current PDT dosimetry mostly involves measurements of light and photosensitizer doses delivered to a patient, the quantification of ROS production during a treatment would be the ultimate dosimetry of PDT. Technically, it is very difficult and expensive to directly measure the fluorescence from 1O2, due to its extreme short lifetime and weak signal strength. In this paper, Photofrin(R) and 635nm laser were used to generate 1O2 and superoxide in a PDT in solution. Compound 3,7- dihydro-6-{4-[2-(N"-(5-fluoresceinyl) thioureido) ethoxy] phenyl}-2- methylimidazo{1,2-a} pyrazin-3-one sodium salt,an Cyp- ridina luciferin analog commonly referred as FCLA, was used as a chemical reporter of ROS. The 532nm chemiluminescence (CL) from the reaction of the FCLA and ROS was detected with a photon multiplier tube (PMT) system operating at single photon counting mode. With the setup, we have made detections of ROS generated by PDT in real time. By varying the amount of conventional PDT dosage (photosensitizer concentration, light irradiation fluence and its delivery rate) and the amount of FCLA, the intensity of CL and its consumption rate were investigated. The results show that the intensity and temporal profile of CL are highly related to the PDT treatment parameters. This suggests that FCLA CL may provide a highly potential alternative for ROS detection during PDT.

  2. Force spectroscopy measurements show that cortical neurons exposed to excitotoxic agonists stiffen before showing evidence of bleb damage.

    Directory of Open Access Journals (Sweden)

    Shan Zou

    Full Text Available In ischemic and traumatic brain injury, hyperactivated glutamate (N-methyl-D-aspartic acid, NMDA and sodium (Nav channels trigger excitotoxic neuron death. Na(+, Ca(++ and H2O influx into affected neurons elicits swelling (increased cell volume and pathological blebbing (disassociation of the plasma membrane's bilayer from its spectrin-actomyosin matrix. Though usually conflated in injured tissue, cell swelling and blebbing are distinct processes. Around an injury core, salvageable neurons could be mildly swollen without yet having suffered the bleb-type membrane damage that, by rendering channels leaky and pumps dysfunctional, exacerbates the excitotoxic positive feedback spiral. Recognizing when neuronal inflation signifies non-lethal osmotic swelling versus blebbing should further efforts to salvage injury-penumbra neurons. To assess whether the mechanical properties of osmotically-swollen versus excitotoxically-blebbing neurons might be cytomechanically distinguishable, we measured cortical neuron elasticity (gauged via atomic force microscopy (AFM-based force spectroscopy upon brief exposure to hypotonicity or to excitotoxic agonists (glutamate and Nav channel activators, NMDA and veratridine. Though unperturbed by solution exchange per se, elasticity increased abruptly with hypotonicity, with NMDA and with veratridine. Neurons then invariably softened towards or below the pre-treatment level, sometimes starting before the washout. The initial channel-mediated stiffening bespeaks an abrupt elevation of hydrostatic pressure linked to NMDA or Nav channel-mediated ion/H2O fluxes, together with increased [Ca(++]int-mediated submembrane actomyosin contractility. The subsequent softening to below-control levels is consistent with the onset of a lethal level of bleb damage. These findings indicate that dissection/identification of molecular events during the excitotoxic transition from stiff/swollen to soft/blebbing is warranted and should be

  3. Designing MgFe{sub 2}O{sub 4} decorated on green mediated reduced graphene oxide sheets showing photocatalytic performance and luminescence property

    Energy Technology Data Exchange (ETDEWEB)

    Shetty, Krushitha [Department of Nanotechnology, PG Center, Bangalore Region, VIAT, VTU, Muddenahalli, Chikkaballapur 562101 (India); Dr. D. Premachandrasagar Centre for Advanced Materials, DSCE, Bangalore 560078 (India); Lokesh, S.V. [Department of Nanotechnology, PG Center, Bangalore Region, VIAT, VTU, Muddenahalli, Chikkaballapur 562101 (India); Rangappa, Dinesh, E-mail: dineshrangappa@gmail.com [Department of Nanotechnology, PG Center, Bangalore Region, VIAT, VTU, Muddenahalli, Chikkaballapur 562101 (India); Nagaswarupa, H.P., E-mail: nagaswarupa77@gmail.com [Research Center, Department of Science, East West Institute of Technology, Bangalore 560091 (India); Nagabhushana, H., E-mail: bhushanvlc@gmail.com [Prof. CNR Rao Centre for Advanced Materials, Tumkur University, Tumkur 572103 (India); Anantharaju, K.S., E-mail: iamananthkurupalya@gmail.com [Department of Chemistry, Dayananda Sagar College of Engineering, Shavige Malleshwara Hills, Kumaraswamy Layout, Bangalore 560078 (India); Dr. D. Premachandrasagar Centre for Advanced Materials, DSCE, Bangalore 560078 (India); Prashantha, S.C. [Research Center, Department of Science, East West Institute of Technology, Bangalore 560091 (India); Vidya, Y.S. [Department of Physics, Lal Bahadur Shastri Government First Grade College, Bangalore, 560032 (India); Sharma, S.C. [Dr. D. Premachandrasagar Centre for Advanced Materials, DSCE, Bangalore 560078 (India); Department of Mechanical Engineering, DSCE, Bangalore-560078 (India)

    2017-02-15

    Here, a green route has been reported to convert Graphene Oxide (GO) to reduced graphene oxide (RGO) using clove extract. A modest and eco-accommodating sol-gel strategy has been employed to prepare MgFe{sub 2}O{sub 4} nanoparticles, MgFe{sub 2}O{sub 4}–RGO nanocomposite samples. The samples were analyzed by Powder X-ray diffraction (PXRD), Fourier Transform Infrared Spectroscopy (FTIR), UV–Visible Spectroscopy, Scanning Electron Microcopy (SEM), Transmission Electron Microscopy (TEM), Photoluminescence (PL) and Electrochemical Impedance Spectroscopy (EIS). PXRD result revealed that the prepared samples were cubic spinel in nature. SEM results uncovered flake like surface morphology of the prepared nanomaterial. Better PL emission signature was observed when excited at 329 nm. PL studies demonstrated that the present samples were potential for the fabrication of white component of white light emitting diodes (WLEDs). Further, MgFe{sub 2}O{sub 4}–RGO nanocomposite showed enhanced photocatalytic movement (PCM) and photostability under Sunlight in the decomposition of Malachite Green (MG) compared to MgFe{sub 2}O{sub 4}. This can be attributed to the interaction of MgFe{sub 2}O{sub 4} surface with RGO sheets which results in PL quenching, demonstrates that the recombination of photo-induced electrons and holes in MgFe{sub 2}O{sub 4}–RGO nanocomposite is more effectively inhibited. A possible mechanism for the enhanced properties of MgFe{sub 2}O{sub 4}–RGO nanocomposite was discussed. Moreover, MgFe{sub 2}O{sub 4}–RGO photocatalyst also showed easy magnetic separation with high reusability. These results unveil that the synthesized sample can be used in display applications and also as a potential photocatalyst. - Graphical abstract: Green mediated reduced graphene oxide with MgFe{sub 2}O{sub 4} for display applications and also as a potential photocatalyst. - Highlights: • Synthesized GO was reduced to RGO by green route using clove extract. • Mg

  4. 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.

  5. 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

  6. 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.

  7. 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)

  8. Microvascular and mitochondrial PO 2 simultaneously measured by oxygen-dependent delayed luminescence

    NARCIS (Netherlands)

    S.I.A. Bodmer (Sander I. A.); G. Balestra (Gianmarco); F.A. Harms (Floor A.); T. Johannes (Tanja); N.J.H. Raat (Nicolaas); R.J. Stolker (Robert); E.G. Mik (Egbert)

    2012-01-01

    textabstractMeasurement of tissue oxygenation is a complex task and various techniques have led to a wide range of tissue PO 2 values and contradictory results. Tissue is compartmentalized in microcirculation, interstitium and intracellular space and current techniques are biased towards a certain

  9. A new sensitive system for measurement of thermally and optically stimulated luminescence

    DEFF Research Database (Denmark)

    Markey, B.G.; Bøtter-Jensen, L.; Poolton, N.R.J.

    1996-01-01

    optics of the system with a combination of ellipsoidal mirrors and light guides, which also serve to make the system more flexible in choice of excitation source when OSL measurements are required. A variety of new light sources might be employed, adapted to allow the most efficient wavelengths...

  10. 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)

  11. Radiation doses measured by TLD (thermo luminescent dosimeter) in x-ray examination

    International Nuclear Information System (INIS)

    Yamamoto, Seiichi; Hiraki, Motoji; Murakami, Shozo; Nishikawa, Naozo; Yagi, Takayuki

    1977-01-01

    By means of TLD, we measured the radiation doses to the skin in the central area of the field of radiation and doses scattered outside of the radiation field, utilizing a phantom to define a suitable radiation field. Clinically, when radiography of the gall bladder and the chest was done, we measured both the radiation doses of the central skin area where radiation was done and the skin above the area of the female gonads. In radiography of the chest, the radiation doses to the skin area above the female gonads situate was under 0.1 mR. When female gonads are less than 15 cm from the margin of the radiation field of the radiation dose can be decreased by 30% if gum sheets containing lead are used to cover the skin area outside the radiation field. (auth.)

  12. 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.

  13. Characterisation of blue-light stimulated luminescence components in different quartz samples: Implications for dose measurement

    DEFF Research Database (Denmark)

    Jain, M.; Murray, A.S.; Bøtter-Jensen, L.

    2003-01-01

    -aliquot dose-evaluation protocols seem to be relatively free of complications when applied to quartz dominated by the fast OSL component coming from 325degreesC TL region, but this may not be true for quartz in which other components are more significant. An adequate understanding of how different OSL...... results from measurement of (a) sensitisation, (b) thermal stability, (c) recuperation, and (d) infrared response as a function of stimulation temperature from 3 different samples of sedimentary quartz selected on the basis of relative OSL contribution from different blue light stimulated linearly...

  14. 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.)

  15. 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

  16. 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)

  17. 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.

  18. Analysis of combustion in an ATAC engine with measurement of radical luminescence; Radical hakko keisoku ni yoru ATAC engine no nensho kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Park, Y; Oguma, H; Ueda, H; Iida, N [Keio University, Tokyo (Japan)

    1997-10-01

    In order to make clear of the combustion mechanism and the frame structure in two stake, so called, active thermo-atmosphere combustion (ATAC) engine fueled by gasoline and methanol, we measured the 2-demensional images of OH, CH and C2 radical band spectra in both ATAC and SI combustion mode. From the results of pressure data in the cylinder, the heat release rate was calculated. We evaluated the correlation of radical luminescence intensity and the rate of heat release. 3 refs., 4 figs., 2 tabs.

  19. 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 ...

  20. 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)

  1. 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)

  2. Latency-Based and Psychophysiological Measures of Sexual Interest Show Convergent and Concurrent Validity.

    Science.gov (United States)

    Ó Ciardha, Caoilte; Attard-Johnson, Janice; Bindemann, Markus

    2018-04-01

    Latency-based measures of sexual interest require additional evidence of validity, as do newer pupil dilation approaches. A total of 102 community men completed six latency-based measures of sexual interest. Pupillary responses were recorded during three of these tasks and in an additional task where no participant response was required. For adult stimuli, there was a high degree of intercorrelation between measures, suggesting that tasks may be measuring the same underlying construct (convergent validity). In addition to being correlated with one another, measures also predicted participants' self-reported sexual interest, demonstrating concurrent validity (i.e., the ability of a task to predict a more validated, simultaneously recorded, measure). Latency-based and pupillometric approaches also showed preliminary evidence of concurrent validity in predicting both self-reported interest in child molestation and viewing pornographic material containing children. Taken together, the study findings build on the evidence base for the validity of latency-based and pupillometric measures of sexual interest.

  3. Advances in luminescence instrument systems

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Bulur, E.; Duller, G.A.T.

    2000-01-01

    We report on recent advances in the development of luminescence measurement systems and techniques at Riso. These include: (1) optical stimulation units based on new-generation powerful blue light (470 nm) emitting diodes providing up to 28 mW/cm(2) for OSL measurements; (2) an infrared (830 nm...

  4. Added value measures in education show genetic as well as environmental influence.

    Science.gov (United States)

    Haworth, Claire M A; Asbury, Kathryn; Dale, Philip S; Plomin, Robert

    2011-02-02

    Does achievement independent of ability or previous attainment provide a purer measure of the added value of school? In a study of 4000 pairs of 12-year-old twins in the UK, we measured achievement with year-long teacher assessments as well as tests. Raw achievement shows moderate heritability (about 50%) and modest shared environmental influences (25%). Unexpectedly, we show that for indices of the added value of school, genetic influences remain moderate (around 50%), and the shared (school) environment is less important (about 12%). The pervasiveness of genetic influence in how and how much children learn is compatible with an active view of learning in which children create their own educational experiences in part on the basis of their genetic propensities.

  5. 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....

  6. 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.

  7. 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

  8. 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...

  9. 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.

  10. 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

  11. 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.

  12. Luminescent lanthanide coordination polymers

    Energy Technology Data Exchange (ETDEWEB)

    Ma, L.; Evans, O.R.; Foxman, B.M.; Lin, W.

    1999-12-13

    One-dimensional lanthanide coordination polymers with the formula Ln(isonicotinate){sub 3}(H{sub 2}O){sub 2} (Ln = Ce, Pr, Nd, Sm, Eu, Tb; 1a-f) were synthesized by treating nitrate or perchlorate salts of Ln(III) with 4-pyridinecarboxaldehyde under hydro(solvo)thermal conditions. Single-crystal and powder X-ray diffraction studies indicate that these lanthanide coordination polymers adopt two different structures. While Ce(III), Pr(III), and Nd(III) complexes adopt a chain structure with alternating Ln-(carboxylate){sub 2}-Ln and Ln-(carboxylate){sub 4}-Ln linkages, Sm(III), Eu(III), and Tb(III) complexes have a doubly carboxylate-bridged infinite-chain structure with one chelating carboxylate group on each metal center. In both structures, the lanthanide centers also bind to two water molecules to yield an eight-coordinate, square antiprismatic geometry. The pyridine nitrogen atoms of the isonicotinate groups do not coordinate to the metal centers in these lanthanide(III) complexes; instead, they direct the formation of Ln(III) coordination polymers via hydrogen bonding with coordinated water molecules. Photoluminescence measurements show that Tb(isonicotinate){sub 3}(H{sub 2}O){sub 2} is highly emissive at room temperature with a quantum yield of {approximately}90%. These results indicate that highly luminescent lanthanide coordination polymers can be assembled using a combination of coordination and hydrogen bonds. Crystal data for 1a: monoclinic space group P2{sub 1}/c, a = 9.712(2) {angstrom}, b = 19.833(4) {angstrom}, c = 11.616(2) {angstrom}, {beta} = 111.89(3){degree}, Z = 4. Crystal data for 1f: monoclinic space group C2/c, a = 20.253(4) {angstrom}, b = 11.584(2) {angstrom}, c = 9.839(2) {angstrom}, {beta} = 115.64(3){degree}, Z = 8.

  13. 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.

  14. Hydrothermal synthesis, characterization and luminescent ...

    Indian Academy of Sciences (India)

    that nanoparticles have cylindrical shape and crystalline nature of nanoparticles was confirmed by SAED patterns. Down- conversion (DC) luminescent properties of doped NaLaF4 were also .... Figure 1 shows the XRPD patterns of undoped NaLaF4 and .... which can be assigned to the transitions from the 7F6 ground.

  15. Calibration beads containing luminescent lanthanide ion complexes

    Science.gov (United States)

    The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, will be enhanced by the availability of narrow-band emitting lanthanide calibration beads. These beads can also be used to characterize spectrographic instruments, including mi...

  16. 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.

  17. 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.

  18. 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.

  19. The wildgeographer avatar shows how to measure soil erosion rates by means of a rainfall simulator

    Science.gov (United States)

    Cerdà, Artemi; González Pelayo, Óscar; Pereira, Paulo; Novara, Agata; Iserloh, Thomas; Prosdocimi, Massimo

    2015-04-01

    This contribution to the immersed worlds wish to develop the avatar that will teach the students and other scientists how to develop measurements of soil erosion, surface runoff and wetting fronts by means of simulated rainfall experiments. Rainfall simulation is a well established and knows methodology to measure the soil erosion rates and soil hydrology under controlled conditions (Cerdà 1998a; Cerdà, 1998b; Cerdà and Jurgensen, 2011; Dunkerley, 2012; Iserloh et al., 2012; Iserloh et al., 2013; Ziadat and Taimeh, 2013; Butzen et al., 2014). However, is a method that requires a long training and expertise to avoid mismanagement and mistaken. To use and avatar can help in the teaching of the technique and the dissemination of the findings. This contribution will show to other avatars how to develop an experiment with simulated rainfall and will help to take the right decision in the design of the experiments. Following the main parts of the experiments and measurements the Wildgeographer avatar must develop: 1. Determine the objectives and decide which rainfall intensity and distribution, and which plot size to be used. Choose between a laboratory or a field rainfall simulation. 2. Design of the rainfall simulator to achieve the objectives: type of rainfall simulator (sprayer or drop former) and calibrate. 3. The experiments are carried out. 4. The results are show. Acknowledgements To the "Ministerio de Economía and Competitividad" of Spanish Government for finance the POSTFIRE project (CGL2013- 47862-C2-1-R). The research projects GL2008-02879/BTE, LEDDRA 243857 and PREVENTING AND REMEDIATING DEGRADATION OF SOILS IN EUROPE THROUGH LAND CARE (RECARE)FP7-ENV-2013- supported this research. References Butzen, V., Seeger, M., Wirtz, S., Huemann, M., Mueller, C., Casper, M., Ries, J. B. 2014. Quantification of Hortonian overland flow generation and soil erosion in a Central European low mountain range using rainfall experiments. Catena, 113, 202-212. Cerdà, A

  20. 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.

  1. FDA Food Code recommendations: how do popular US baking shows measure up?

    Directory of Open Access Journals (Sweden)

    Valerie Cadorett

    2018-05-01

    Full Text Available The purpose of this study was to determine if popular US baking shows follow the FDA Food Code recommendations and critical food safety principles. This cross-sectional study examined a convenience sample of 75 episodes from three popular baking shows. The three shows were about competitively baking cupcakes, competitively baking cakes, and baking in a popular local bakery. Twenty-five episodes from each show were viewed. Coding involved tallying how many times 17 FDA Food Code recommendations were or were not followed. On each show, bare hands frequently came in contact with ready-to-eat food. On a per-hour basis, this occurred 80, 155, and 176 times on shows 1-3, respectively. Hands were washed before cooking three times on the three shows and never for the recommended 20 seconds. On each show, many people touched food while wearing jewelry other than a plain wedding band, for an average of at least 7 people per hour on each show. Shows 1-3 had high rates of long-haired bakers not wearing hair restraints (11.14, 6.57, and 14.06 per hour, respectively. Shows 1 and 2 had high rates of running among the bakers (22.29 and 10.57 instances per hour, respectively. These popular baking shows do not demonstrate proper food safety techniques put forth by the FDA and do not contribute the reduction of foodborne illnesses through proper food handling.

  2. 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.

  3. 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.

  4. 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.

  5. 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)

  6. Mitochondria Targetable Time-Gated Luminescence Probe for Singlet Oxygen Based on a β-Diketonate-Europium Complex.

    Science.gov (United States)

    Sun, Jingyan; Song, Bo; Ye, Zhiqiang; Yuan, Jingli

    2015-12-21

    Singlet oxygen ((1)O2) plays a key role in the photodynamic therapy (PDT) technique of neoplastic diseases. In this work, by using a 9,10-dimethyl-2-anthryl-containing β-diketone, 1,1,1,2,2-pentafluoro-5-(9',10'-dimethyl-2'-anthryl)-3,5-pentanedione (Hpfdap), as a (1)O2-recognition ligand, a novel β-diketonate-europium(III) complex that can act as a luminescence probe for (1)O2, [Eu(pfdap)3(tpy)] (tpy = 2,2',2″-terpyridine), has been designed and synthesized for the time-gated luminescence detection of (1)O2 in living cells. The complex is weakly luminescent due to the quenching effect of 9,10-dimethyl-2-anthryl groups. After reaction with (1)O2, accompanied by the formation of endoperoxides of 9,10-dimethyl-2-anthryl groups, the luminescence quenching disappears, so that the long-lived luminescence of the europium(III) complex is switched on. The complex showed highly selective luminescence response to (1)O2 with a remarkable luminescence enhancement. Combined with the time-gated luminescence imaging technique, the complex was successfully used as a luminescent probe for the monitoring of the time-dependent generation of (1)O2 in 5-aminolevulinic acid (a PDT drug) loaded HepG2 cells during the photodynamic process. In addition, by coloading the complex and a mitochondrial indicator, Mito-Tracker Green, into HepG2 cells, the specific localization of [Eu(pfdap)3(tpy)] molecules in mitochondria of HepG2 cells was demonstrated by confocal fluorescence imaging measurements.

  7. 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.

  8. 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.

  9. Gait stability and variability measures show effects of impaired cognition and dual tasking in frail people

    Directory of Open Access Journals (Sweden)

    de Vries Oscar J

    2011-01-01

    Full Text Available Abstract Background Falls in frail elderly are a common problem with a rising incidence. Gait and postural instability are major risk factors for falling, particularly in geriatric patients. As walking requires attention, cognitive impairments are likely to contribute to an increased fall risk. An objective quantification of gait and balance ability is required to identify persons with a high tendency to fall. Recent studies have shown that stride variability is increased in elderly and under dual task condition and might be more sensitive to detect fall risk than walking speed. In the present study we complemented stride related measures with measures that quantify trunk movement patterns as indicators of dynamic balance ability during walking. The aim of the study was to quantify the effect of impaired cognition and dual tasking on gait variability and stability in geriatric patients. Methods Thirteen elderly with dementia (mean age: 82.6 ± 4.3 years and thirteen without dementia (79.4 ± 5.55 recruited from a geriatric day clinic, walked at self-selected speed with and without performing a verbal dual task. The Mini Mental State Examination and the Seven Minute Screen were administered. Trunk accelerations were measured with an accelerometer. In addition to walking speed, mean, and variability of stride times, gait stability was quantified using stochastic dynamical measures, namely regularity (sample entropy, long range correlations and local stability exponents of trunk accelerations. Results Dual tasking significantly (p Conclusions The observed trunk adaptations were a consistent instability factor. These results support the concept that changes in cognitive functions contribute to changes in the variability and stability of the gait pattern. Walking under dual task conditions and quantifying gait using dynamical parameters can improve detecting walking disorders and might help to identify those elderly who are able to adapt walking

  10. Direct measurements show decreasing methane emissions from natural gas local distribution systems in the United States.

    Science.gov (United States)

    Lamb, Brian K; Edburg, Steven L; Ferrara, Thomas W; Howard, Touché; Harrison, Matthew R; Kolb, Charles E; Townsend-Small, Amy; Dyck, Wesley; Possolo, Antonio; Whetstone, James R

    2015-04-21

    Fugitive losses from natural gas distribution systems are a significant source of anthropogenic methane. Here, we report on a national sampling program to measure methane emissions from 13 urban distribution systems across the U.S. Emission factors were derived from direct measurements at 230 underground pipeline leaks and 229 metering and regulating facilities using stratified random sampling. When these new emission factors are combined with estimates for customer meters, maintenance, and upsets, and current pipeline miles and numbers of facilities, the total estimate is 393 Gg/yr with a 95% upper confidence limit of 854 Gg/yr (0.10% to 0.22% of the methane delivered nationwide). This fraction includes emissions from city gates to the customer meter, but does not include other urban sources or those downstream of customer meters. The upper confidence limit accounts for the skewed distribution of measurements, where a few large emitters accounted for most of the emissions. This emission estimate is 36% to 70% less than the 2011 EPA inventory, (based largely on 1990s emission data), and reflects significant upgrades at metering and regulating stations, improvements in leak detection and maintenance activities, as well as potential effects from differences in methodologies between the two studies.

  11. A New Optic Technology for Measuring Oxygen Dissolved in Water: Luminescence Dissolved Oxygen (LDO); Nueva tecnologia optica para la medicion de oxigeno disuelto en agua: oxigeno disuelto por luminiscencia (LDO)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

    Continual measurement of oxygen in the active sludge tank is a very important parameter is the biological treatment of waste waters. Traditional electrochemical sensors are based on polarographic or galvanic cells, a technique which produces electrolyte consumption and progressive deterioration of the anode. Both effects inevitable lead to a drift in the measurement signal, which requires periodical calibration. Lange has developed a completely new technique for its new LDO sensor for measuring oxygen concentration in waste waters. This technique is based on the luminescent radiation of a luminescent substance (luminophore) and reduces the determination to the purely physical measurement of time, so that, in theory it is free of drift and there is no need for the use to calibrate the sensor. (Author)

  12. Luminescence detection of phase transitions in crystals and nanoparticle inclusions

    International Nuclear Information System (INIS)

    Townsend, P. D.; Yang, B.; Wang, Y.

    2008-01-01

    Luminescence measurements are extremely sensitive to variations in structural environment and thus have the potential to probe distortions of fluorescence sites. Changes can be monitored via luminescence efficiency, emission spectra or excited state lifetimes and these factors are influenced by the local neighbourhood around the emission site, and therefore by structure, composition, pressure and temperature. A rarely exploited approach for condensed matter has been to use the changes in luminescence responses during heating or cooling of a material to provide a rapid survey to detect the presence of phase transitions. One can often differentiate between bulk and surface effects by contrasting results from radioluminescence for bulk responses, and cathodoluminescence or photoluminescence for surface effects. One expects that discontinuous changes in optical parameters occur during temperature changes through phase transitions of insulating materials. In practice, optical signals also exist from surface states of fullerenes and high temperature superconductors etc which identify the presence of structural or superconducting transitions. Numerous examples are cited which match standard documented transitions. Interestingly many examples show the host signals are strongly sensitive to impurity phase transitions from inclusions such as nanoparticles of water, N 2 , O 2 or CO 2 . Recent luminescence data reveal many examples of new transitions, hysteresis and irreversible changes. The signals equally respond to relaxations of a structure and surprisingly indicate that in some materials, such as SrTiO 3 or ZnO, ion implantation of the surface triggers relaxations and phase changes throughout the bulk of the material. Luminescence routes to detect phase transitions are powerful tools but have a tiny literature and so the subject is ideal for rapid exploitation and development. (Author)

  13. CT-scan-monitored electrical-resistivity measurements show problems achieving homogeneous saturation

    International Nuclear Information System (INIS)

    Sprunt, E.S.; Davis, R.M.; Muegge, E.L.; Desai, K.P.

    1991-01-01

    This paper reports on x-ray computerized tomography (CT) scans obtained during measurement of the electrical resistivity of core samples which revealed some problems in obtaining uniform saturation along the lengths of the samples. The electrical resistivity of core samples is measured as a function of water saturation to determine the saturation exponent used in electric-log interpretation. An assumption in such tests is that the water saturation is uniformly distributed. Failure of this assumption can result in errors in the determination of the saturation exponent. Three problems were identified in obtaining homogeneous water saturation in two samples of a Middle Eastern carbonate grainstone: a stationary front formed in one sample at 1-psi oil/brine capillary pressure, a moving front formed at oil/brine capillary pressure ≤4 psi in samples tested in fresh mixed-wettability and cleaned water-wet states, and the heterogeneous fluid distribution caused by a rapidly moving front did not dissipate when the capillary pressure was eliminated in the samples

  14. CT-scan-monitored electrical resistivity measurements show problems achieving homogeneous saturation

    International Nuclear Information System (INIS)

    Sprunt, E.S.; Coles, M.E.; Davis, R.M.; Muegge, E.L.; Desai, K.P.

    1991-01-01

    X-ray CT scans obtained during measurement of the electrical resistivity of core samples revealed some problems in obtaining uniform saturation along the length of the sample. In this paper the electrical resistivity of core samples is measured as a function of water saturation to determine the saturation exponent, which is used in electric log interpretation. An assumption in such tests is that the water saturation is uniformly distributed. Failure of this assumption can result in errors in the determination of the saturation exponent. Three problems were identified in obtaining homogeneous water saturation in two samples of a Middle Eastern carbonate grainstone. A stationary front formed in one sample at 1 psi oil/brine capillary pressure. A moving front formed at oil/brine capillary pressures of 4 psi or less in both samples tested, in both a fresh mixed-wettability state and in a cleaned water-wet state. In these samples, the heterogeneous fluid distribution caused by a rapidly moving front did not dissipate when the capillary pressure was eliminated

  15. 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

  16. Sensitization effects of supramolecular assemblies on the luminescence of terbium-ion prulifloxacin complexes

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hong; Yi Chongyue; Li Xue; Fang Fang [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Yang Yajiang, E-mail: yjyang@mail.hust.edu.c [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2011-04-15

    Luminescence enhancement of terbium-ion prulifloxacin complexes (Tb(III)-PUFX) in supramolecular hydrogels formed by assembly of 1,3:2,4-di-O-benzylidene-D-sorbitol (DBS) was investigated by steady-state fluorescence, varying temperature fluorescence and time-resolved fluorescence. The luminescence images show that Tb(III)-PUFX were dispersed in the DBS gels. The luminescence intensity of Tb(III)-PUFX in the DBS gels was significantly increased in comparison with that in corresponding aqueous solutions. The varying temperature fluorescent spectra show that the luminescence intensity of Tb(III)-PUFX decreased with an increase in the temperature. This implies that the luminescence enhancement of Tb(III)-PUFX is related to the dissociation and the formation of the DBS assemblies. Time-resolved fluorescence measurements show slower rotational motion in DBS gels in comparison with that in the corresponding aqueous solutions. This may be ascribed to a unique microstructure of three-dimensional network formed by DBC aggregates, resulting in deactivation of the nonradiative relaxation. The images of field emission scanning electron microscopy and polarized optical microscopy indicate that the morphology of the DBS assemblies was not influenced upon addition of Tb(III)-PUFX to the DBS gels.

  17. 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

  18. Energy dependence measurement of small-type optically stimulated luminescence (OSL) dosimeter by means of characteristic X-rays induced with general diagnostic X-ray equipment.

    Science.gov (United States)

    Takegami, Kazuki; Hayashi, Hiroaki; Okino, Hiroki; Kimoto, Natsumi; Maehata, Itsumi; Kanazawa, Yuki; Okazaki, Tohru; Hashizume, Takuya; Kobayashi, Ikuo

    2016-01-01

    For X-ray inspections by way of general X-ray equipment, it is important to measure an entrance-skin dose. Recently, a small optically stimulated luminescence (OSL) dosimeter was made commercially available by Landauer, Inc. The dosimeter does not interfere with the medical images; therefore, it is expected to be a convenient detector for measuring personal exposure doses. In an actual clinical situation, it is assumed that X-rays of different energies will be detected by a dosimeter. For evaluation of the exposure dose measured by a dosimeter, it is necessary to know the energy dependence of the dosimeter. Our aim in this study was to measure the energy dependence of the OSL dosimeter experimentally in the diagnostic X-ray region. Metal samples weighing several grams were irradiated and, in this way, characteristic X-rays having energies ranging from 8 to 85 keV were generated. Using these mono-energetic X-rays, the dosimeter was irradiated. Simultaneously, the fluence of the X-rays was determined with a CdTe detector. The energy-dependent efficiency of the dosimeter was derived from the measured value of the dosimeter and the fluence. Moreover, the energy-dependent efficiency was calculated by Monte-Carlo simulation. The efficiency obtained in the experiment was in good agreement with that of the simulation. In conclusion, our proposed method, in which characteristic X-rays are used, is valuable for measurement of the energy dependence of a small OSL dosimeter in the diagnostic X-ray region.

  19. Investigations of the luminescence of phosphate glasses with respect to their application as solid dosemeters

    International Nuclear Information System (INIS)

    Regulla, D.F.

    1977-03-01

    A comprehensive presentation of the luminescent properties of phosphate glass is worked out. The extensive investigations show an essential enlargement of the knowledge on the luminescence of phosphate glass existing hitherto. These results form the basis for a detailed discussion of the luminescence mechanism. By applying additional results of measurements concerning optical and paramagnetic absorption, enabling the access to the atomic effect, propositions were developed for models of absorption, excitation and luminous centers relevant for dosimetry for which Ag ++ was found to be the constituent determining the centers. The interpretation of the luminescence phenomena within the frame of these models leads to considerable corrections on the existing concepts. At the same time the comparability of Ag-doped phosphate glasses and alkali halogenides is shown with respect to their luminescence behaviour, and with it an argument for the existence of crystal-like short-order regions in the amorphous glass is provided. This result serves as a basis for a discussion of the centers in the band model. Further investigations dealt with the quantities of influence for the practical application of the dosemeter. By interpretation of these results explanations are given for the effect of irradiation and evaluation temperatures, of LET, the dose, and UV light on the measuring signal. The phenomenon of 'pre-dose', for which especially surface effects have been detected as cause, is discussed under the aspect of a boundary layer theory. (orig./HP) [de

  20. 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)

  1. 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)

  2. Development and measurement of luminescence properties of Ce-doped Cs2LiGdBr6 crystals irradiated with X-ray, γ-ray and proton beam

    Science.gov (United States)

    Jang, Jonghun; Kim, H. J.; Rooh, Gul; Kim, Sunghwan

    2017-12-01

    The effect of higher Ce-concentration on the luminescence and scintillation properties of Cs2LiGdBr6 single crystals are studied. We used the Bridgman method for the growth of Ce-doped Cs2LiGdBr6 single crystals. Luminescence properties of the grown crystals are measured by X-ray and proton excitations. We measured the pulse height and fluorescence decay time spectra of Cs2LiGdBr6:Ce3+ with a bi-alkali photo multiplier tube (PMT) under γ-ray excitation from 137Cs source. Improvements in the scintillation properties are observed with the increase of Ce-concentration in the lattice. Detailed procedure of the crystal growth is also discussed.

  3. 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

  4. 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.

  5. 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.

  6. SU-F-T-327: Total Body Irradiation In-Vivo Dose Measurements Using Optically Stimulated Luminescence (OSL) NanoDots and Farmer Type Ion Chamber

    International Nuclear Information System (INIS)

    Kaur, H; Kumar, S; Sarkar, B; Ganesh, T; Giri, U; Jassal, K; Rathinamuthu, S; Gulia, G; Gopal, V; Mohanti, B; Munshi, A

    2016-01-01

    Purpose: This study was performed to analyze the agreement between optically stimulated luminescence (OSL) nanoDots measured doses and 0.6 cc Farmer type ionization chamber measured doses during total body irradiation (TBI). Methods: In-vivo dose measurements using OSL nanoDots and Farmer chamber were done in a total of twelve patients who received TBI at our center by bilateral parallel-opposed beams technique. In this technique, the patient is kept inside the TBI box which is filled with rice bags and irradiated using two bilateral parallel opposed beams of 40×40 cm"2 size with 45° collimator rotation at an SSD of 333.5 cm in an Elekta Synergy linear accelerator. All patients received a dose of 2 Gy in single fraction as conditioning regimen. The beams were equally weighted at the midplane of the box. The nanoDots were placed over forehead, right and left neck, right and left lung, umbilicus, right and left abdomen, medial part of thigh, knee and toe. A 0.6 cc Farmer chamber was placed in between the thighs of the patient. Measured doses are reported along with the statistical comparisons using paired sample t-test. Results: For the above sites the mean doses were 212.2±21.1, 218.2±7.6, 218.7±9.3, 215.6±9.5, 217.5±11.5, 214.5±7.7, 218.3±6.8, 221.5±15, 229.1±11.0, 220.5±7.7 and 223.3±5.1 cGy respectively. For all OSL measurements the mean dose was 218.6±11.8 cGy. Farmer chamber measurements yielded a mean dose of 208.8±15.6 cGy. Statistical analysis revealed that there was no significant difference between OSL measured doses in forehead, right and left neck, right and left lung, umbilicus, right and left abdomen and toe and Farmer chamber measured doses (0.72≤p≤0.06). However the mean OSL doses at thigh and knee were statistically different (p<0.05) from the Farmer chamber measurements. Conclusion: OSL measurements were found to be in agreement with Farmer type ionization chamber measurements in in-vivo dosimetry of TBI.

  7. SU-F-T-327: Total Body Irradiation In-Vivo Dose Measurements Using Optically Stimulated Luminescence (OSL) NanoDots and Farmer Type Ion Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, H; Kumar, S; Sarkar, B; Ganesh, T; Giri, U; Jassal, K; Rathinamuthu, S; Gulia, G; Gopal, V; Mohanti, B; Munshi, A [Fortis Memorial Research Institute, Gurgaon, Haryana (India)

    2016-06-15

    Purpose: This study was performed to analyze the agreement between optically stimulated luminescence (OSL) nanoDots measured doses and 0.6 cc Farmer type ionization chamber measured doses during total body irradiation (TBI). Methods: In-vivo dose measurements using OSL nanoDots and Farmer chamber were done in a total of twelve patients who received TBI at our center by bilateral parallel-opposed beams technique. In this technique, the patient is kept inside the TBI box which is filled with rice bags and irradiated using two bilateral parallel opposed beams of 40×40 cm{sup 2} size with 45° collimator rotation at an SSD of 333.5 cm in an Elekta Synergy linear accelerator. All patients received a dose of 2 Gy in single fraction as conditioning regimen. The beams were equally weighted at the midplane of the box. The nanoDots were placed over forehead, right and left neck, right and left lung, umbilicus, right and left abdomen, medial part of thigh, knee and toe. A 0.6 cc Farmer chamber was placed in between the thighs of the patient. Measured doses are reported along with the statistical comparisons using paired sample t-test. Results: For the above sites the mean doses were 212.2±21.1, 218.2±7.6, 218.7±9.3, 215.6±9.5, 217.5±11.5, 214.5±7.7, 218.3±6.8, 221.5±15, 229.1±11.0, 220.5±7.7 and 223.3±5.1 cGy respectively. For all OSL measurements the mean dose was 218.6±11.8 cGy. Farmer chamber measurements yielded a mean dose of 208.8±15.6 cGy. Statistical analysis revealed that there was no significant difference between OSL measured doses in forehead, right and left neck, right and left lung, umbilicus, right and left abdomen and toe and Farmer chamber measured doses (0.72≤p≤0.06). However the mean OSL doses at thigh and knee were statistically different (p<0.05) from the Farmer chamber measurements. Conclusion: OSL measurements were found to be in agreement with Farmer type ionization chamber measurements in in-vivo dosimetry of TBI.

  8. 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.

  9. 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.

  10. Luminescence dose of sand by the huguangyan maar lake

    International Nuclear Information System (INIS)

    Xiong Zhengye; Chen Jinmin; Ding Ping; Shi Wenqing; Ma Weijiang; Zhu Jinhan

    2010-01-01

    Sand samples were collected at different locations from the Huguangyan Maar Lake region in Zhanjiang, Guangdong province in south China. Thermoluminescence (TL) and optical stimulated luminescence (OSL) were measured with coarse grain technique. The TL and OSL dose response were analyzed and their ancient doses were calculated. The result shows that ancient doses measured with TL technique differ from those measured with OSL technique for the same sample, whereas for the samples whose TL ancient dose is close to the veraciousness, there were no evident degree of difference between the ancient doses by OSL and TL. The experiments and analyses can be used for reference in Quaternary period volcano dating. (authors)

  11. Fabrication and characterization of dual-functional ultrafine composite fibers with phase-change energy storage and luminescence properties.

    Science.gov (United States)

    Xi, Peng; Zhao, Tianxiang; Xia, Lei; Shu, Dengkun; Ma, Menjiao; Cheng, Bowen

    2017-01-09

    Ultrafine composite fibers consisting of a thermoplastic polyurethane solid-solid phase-change material and organic lanthanide luminescent materials were prepared through a parallel electrospinning technique as an innovative type of ultrafine, dual-functional fibers containing phase-change and luminescent properties. The morphology and structure, thermal energy storage, and luminescent properties of parallel electrospun ultrafine fibers were investigated. Scanning electron microscopy (SEM) images showed that the parallel electrospun ultrafine fibers possessed the desired morphologies with smaller average fiber diameters than those of traditional mixed electrospun ultrafine fibers. Transmission electron microscopy (TEM) images revealed that the parallel electrospun ultrafine fibers were composed of two parts. Polymeric phase-change materials, which can be directly produced and spun, were used to provide temperature stability, while a mixture of polymethyl methacrylate and an organic lanthanide complex acted as the luminescent unit. Differential scanning calorimetry (DSC) and luminescence measurements indicated that the unique structure of the parallel electrospun ultrafine fibers provides the products with good thermal energy storage and luminescence properties. The fluorescence intensity and the phase-change enthalpy values of the ultrafine fibers prepared by parallel electrospinning were respectively 1.6 and 2.1 times those of ultrafine fibers prepared by mixed electrospinning.

  12. 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

  13. Methods of producing luminescent images

    International Nuclear Information System (INIS)

    Broadhead, P.; Newman, G.A.

    1977-01-01

    A method is described for producing a luminescent image in a layer of a binding material in which is dispersed a thermoluminescent material. The layer is heated uniformly to a temperature of 80 to 300 0 C and is exposed to luminescence inducing radiation whilst so heated. The preferred exposing radiation is X-rays and preferably the thermoluminescent material is insensitive to electromagnetic radiation of wavelength longer than 300 mm. Information concerning preparation of the luminescent material is given in BP 1,347,672; this material has the advantage that at elevated temperatures it shows increased sensitivity compared with room temperature. At temperatures in the range 80 to 150 0 C the thermoluminescent material exhibits 'afterglow', allowing the image to persist for several seconds after the X-radiation has ceased, thus allowing the image to be retained for visual inspection in this temperature range. At higher temperatures, however, there is negligible 'afterglow'. The thermoluminescent layers so produced are particularly useful as fluoroscopic screens. The preferred method of heating the thermoluminescent material is described in BP 1,354,149. An example is given of the application of the method. (U.K.)

  14. Atomic-scale luminescence measurement and theoretical analysis unveiling electron energy dissipation at a p-type GaAs(110) surface

    International Nuclear Information System (INIS)

    Imada, Hiroshi; Miwa, Kuniyuki; Jung, Jaehoon; Shimizu, Tomoko K; Kim, Yousoo; Yamamoto, Naoki

    2015-01-01

    Luminescence of p-type GaAs was induced by electron injection from the tip of a scanning tunnelling microscope into a GaAs(110) surface. Atomically-resolved photon maps revealed a significant reduction in luminescence intensity at surface electronic states localized near Ga atoms. Theoretical analysis based on first principles calculations and a rate equation approach was performed to describe the perspective of electron energy dissipation at the surface. Our study reveals that non-radiative recombination through the surface states (SS) is a dominant process for the electron energy dissipation at the surface, which is suggestive of the fast scattering of injected electrons into the SS. (paper)

  15. Detection of food irradiation with luminescence methods

    International Nuclear Information System (INIS)

    Anderle, H.

    1997-06-01

    Food irradiation is applied as method for the preservation of foods, the prevention of food spoilage and the inhibition of food-borne pathogens. Doses exceeding 10 kGy (10 kJ/kg) are not recommended by the WHO. The different legislation requires methods for the detection and the closimetry of irradiated foods. Among the physical methods based on the radiation-induced changes in inorganic, nonhygroscopic crystalline solids are thermoluminescence (TL), photostimulated luminescence (PSL) and lyoluminescence (LL) measurement. The luminescence methods were tested on natural minerals. Pure quartz, feldspars, calcite, aragonite and dolomite of known origin were irradiated, read out and analyzed to determine the influence of luminescence-activators and deactivators. Carbonate minerals show an orange-red TL easily detectable by blue-sensitive photomultiplier tubes. TIL-inactive carbonate samples may be identified by a lyoluminescence method using the reaction of trapped irradiation-generated charge carriers with the solvent during crystal-lattice breakup. The fine-ground mineral is dissolved in an alkaline complexing agent/chemiluminescence sensitizer/chemiluminescence catalyst (EDTA/luminol/hemin) reagent mixture. The TL and PSL of quartz is too weak to contribute a significant part for the corresponding signals in polymineral dust. Alkali and soda feldspar show intense TL and PSL. The temperature maxima in the TL glow curves allow a clear distinction. PSL does not give this additional information, it suffers from bleaching by ambient light and requires light-protection. Grain disinfestated with low irradiation doses (500 Gy) may not identified by both TL and PSL measurement. The natural TL of feldspar particles may be overlap with the irradiation-induced TL of other minerals. As a routine method, irradiated spices are identified with TL measurement. The dust particles have to be enriched by heavy-liquid flotation and centrifugation. The PSL method allows a clear

  16. SU-F-P-50: Performance Evaluation of Optically Stimulated Luminescence (OSL) NanoDots in Therapy and Imaging In-Vivo Dose Measurement During Patient Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S; Sarkar, B; Kaur, H; Rathinamuthu, S; Giri, U; Jassal, K; Ganesh, T; Munshi, A; Mohanti, B; Krishnankutty, S; Sathiya, J [Fortis Memorial Research Institute, Gurgaon, Haryana (India)

    2016-06-15

    Purpose: This study was designed to evaluate the performance of optically stimulated Luminescence (OSL) nanoDots as in-vivo dosimeter. For the measurements of surface doses as well as scattered plus leakage doses, nanoDots were used during the setup verification as well as during the treatment delivery. Methods: For a total seven patients undergoing radiotherapy by volumetric modulated arc therapy, surface doses from image guidance and scattered plus leakage doses from treatment delivery were measured. Two sets of calibration curves were generated – one for therapy and another for imaging. Two different nanoDots were used for imaging and therapy doses. Imaging nanoDots were placed at the isocenter only at the time of CBCT and therapy nanoDots were placed at 25 cm away from the isocenter (either in cranial or in caudal direction) only at the time of treatment delivery. During the entire course, nanoDots were placed at the same measurement points. NanoDots were read after 15 minutes of their exposure. For the next fraction, nanoDots were corrected for the residual doses from the previous fractions. Results: Measured surface doses during imaging were 0.14±0.32 cGy, 0.11±0.04 cGy, 0.12±0.53 cGy, 0.04±0.02 cGy, 0.13±0.23 cGy, 0.11±0.43 cGy, 0.10±0.04 cGy with overall mean dose of 0.08±0.1 cGy. Measured doses during treatment delivery, indicative of scattered and leakage dose, were 0.84±0.43 cGy, 1.3±0.4 cGy, 1.4±0.4 cGy, 0.18±0.48 cGy, 0.78±0.29 cGy, 0.27±0.08 cGy, 0.78±0.07 cGy with overall mean dose of 0.61±1.3 cGy. Conclusion: This dosimeter can be used as supplementary unit to verify the doses. No change in the prescription is recommended based on nanoDots measurement. This study is on-going therefore we are presenting only mere number of patients. A large volume data will be presented after completion of the study with proper statistical analysis.

  17. 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.

  18. Comparison of intensity-modulated radiotherapy and volumetric-modulated arc therapy dose measurement for head and neck cancer using optical stimulated luminescence dosimeter

    International Nuclear Information System (INIS)

    Lai, Lu-Han; Chuang, Keh-Shih; Lin, Hsin-Hon; Liu, Yi-Chi; Kuo, Chiung-Wen; Lin, Jao-Perng

    2017-01-01

    The in-vivo dose distributions of intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT), a newly developed technique, for head and neck cancer have been investigated for several years. The present study used a head-and-neck RANDO phantom to simulate the clinical conditions of nasopharyngeal carcinoma and compare the radiation doses between VMAT and IMRT. Three types of planning target volume (PTV) profiles were targeted by reducing the PTV surface margin by 0, 3, and 5 mm. An optically stimulated luminescence dosimeter was used to measure the surface doses. The results revealed that VMAT provided on average 16.8–13.8% lower surface doses within the PTV target areas than IMRT. When the PTV margin was reduced by 0 mm, the surface doses for IMRT reached their maximum value, accounting for 75.1% of its prescribed dose (Dp); however, the Dp value of VMAT was only 61.1%. When the PTV margin was reduced by 3 or 5 mm, the surface doses decreased considerably. The observed surface doses were insufficient when the tumours invaded the body surface; however, VMAT exerted larger skin-sparing effects than IMRT when the tumours away from the skin. These results suggest that the skin doses for these two techniques are insufficient for surface tumours. Notably, VMAT can provide lower skin doses for deep tumours. - Highlights: • The surface doses of NPC patients are compared between VMAT and IMRT. • VMAT exerts lower skin dose than IMRT for deep tumours. • The surface tumour coverage is insufficient for VMAT and IMRT.

  19. Detection of irradiated food using photostimulated luminescence

    International Nuclear Information System (INIS)

    Malec-Czechowska, K.; Stachowicz, W.

    2005-01-01

    Detection of irradiated spices, dried mushrooms and flavour blends using photostimulated luminescence (PSL) is presented. PSL measurements were carried out as described in standard PN-EN 13751. A lower threshold (T 1 700 counts/60s) and an upper threshold (T 2 = 5000 counts/60s) were used to classify the sample. PSL intensities below the threshold were classified as from non-irradiated samples and PSL signals above the upper threshold were regarded from irradiated samples. Signal levels between the two thresholds were classified as intermediate, showing that further investigations are necessary. The PSL tests were carried out at Institute Nutritional Physiology, Federal Research Centre for Nutrition in Karlsruhe with a SURRAC PPSL Iradiated food screening system (SURRAC, Glasgow, UK). (author)

  20. Development of Singlet Oxygen Luminescence Kinetics during the Photodynamic Inactivation of Green Algae

    Directory of Open Access Journals (Sweden)

    Tobias Bornhütter

    2016-04-01

    Full Text Available Recent studies show the feasibility of photodynamic inactivation of green algae as a vital step towards an effective photodynamic suppression of biofilms by using functionalized surfaces. The investigation of the intrinsic mechanisms of photodynamic inactivation in green algae represents the next step in order to determine optimization parameters. The observation of singlet oxygen luminescence kinetics proved to be a very effective approach towards understanding mechanisms on a cellular level. In this study, the first two-dimensional measurement of singlet oxygen kinetics in phototrophic microorganisms on surfaces during photodynamic inactivation is presented. We established a system of reproducible algae samples on surfaces, incubated with two different cationic, antimicrobial potent photosensitizers. Fluorescence microscopy images indicate that one photosensitizer localizes inside the green algae while the other accumulates along the outer algae cell wall. A newly developed setup allows for the measurement of singlet oxygen luminescence on the green algae sample surfaces over several days. The kinetics of the singlet oxygen luminescence of both photosensitizers show different developments and a distinct change over time, corresponding with the differences in their localization as well as their photosensitization potential. While the complexity of the signal reveals a challenge for the future, this study incontrovertibly marks a crucial, inevitable step in the investigation of photodynamic inactivation of biofilms: it shows the feasibility of using the singlet oxygen luminescence kinetics to investigate photodynamic effects on surfaces and thus opens a field for numerous investigations.

  1. 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.

  2. 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)

  3. Anticancer drug-DNA interactions measured using a photoinduced electron-transfer mechanism based on luminescent quantum dots.

    Science.gov (United States)

    Yuan, Jipei; Guo, Weiwei; Yang, Xiurong; Wang, Erkang

    2009-01-01

    A sensing system based on the photoinduced electron transfer of quantum dots (QDs) was designed to measure the interaction of anticancer drug and DNA, taking mitoxantrone (MTX) as a model drug. MTX adsorbed on the surface of QDs can quench the photoluminescence (PL) of QDs through the photoinduced electron-transfer process; and then the addition of DNA will bring the restoration of QDs PL intensity, as DNA can bind with MTX and remove it from QDs. Sensitive detection of MTX with the detection limit of 10 nmol L(-1) and a linear detection range from 10 nmol L(-1) to 4.5 micromol L(-1) was achieved. The dependence of PL intensity on DNA amount was successfully utilized to investigate the interactions between MTX and DNA. Both the binding constants and the sizes of binding site of MTX-DNA interactions were calculated based on the equations deduced for the PL recovery process. The binding constant obtained in our experiment was generally consistent with previous reports. The sensitive and speedy detection of MTX as well as the avoidance of modification or immobilization process made this system suitable and promising in the drug-DNA interaction studies.

  4. Limestone: some observations on luminescence in the region of 360 nm

    International Nuclear Information System (INIS)

    Galloway, R.B.

    2003-01-01

    An empirical study of luminescence around 360 nm from limestone is presented. Thermoluminescence glow curves from natural limestone show broad peaks at 440 deg. C, 350 deg. C, 530 deg. C and 286 deg. C in order of decreasing amplitude in contrast to the usual observation, for luminescence around 535 nm, of a sharp peak at 286 deg. C with a broader less intense peak at 350 deg. C. Recuperation occurs around 350 deg. C and 525 deg. C, which has a time dependence consistent with quantum tunnelling. Dependent on the history of heating and light exposure of the sample, sharp peaks at about 325 deg. C and 425 deg. C can be observed. Laboratory irradiated limestone shows a peak at 140 deg. C. The stimulation of luminescence by light of 470 nm with preheating at 145 deg. C for 300 s, shows an increasing signal for successive cycles of measurement associated with the heating, light exposure having little influence. Beta irradiation of a sample, with the same measurement conditions, gives a signal which increases in proportion to radiation dose but which does not survive storage for 17 h. Time resolved luminescence spectra, with no preheating, show a luminescence lifetime between stimulation and emission of less than a few μs for natural limestone, and an exponential increase in signal with increase in temperature (over the rang 20-167 deg. C) during stimulation. A signal proportional to laboratory applied beta dose is measurable at room temperature, with lifetime between stimulation and emission of this signal of 35 μs, but it does not survive heating to 100 deg. C

  5. 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.

  6. Estimation and correction of produced light from prompt gamma photons on luminescence imaging of water for proton therapy dosimetry

    Science.gov (United States)

    Yabe, Takuya; Komori, Masataka; Toshito, Toshiyuki; Yamaguchi, Mitsutaka; Kawachi, Naoki; Yamamoto, Seiichi

    2018-02-01

    Although the luminescence images of water during proton-beam irradiation using a cooled charge-coupled device camera showed almost the same ranges of proton beams as those measured by an ionization chamber, the depth profiles showed lower Bragg peak intensities than those measured by an ionization chamber. In addition, a broad optical baseline signal was observed in depths that exceed the depth of the Bragg peak. We hypothesize that this broad baseline signal originates from the interaction of proton-induced prompt gamma photons with water. These prompt gamma photons interact with water to form high-energy Compton electrons, which may cause luminescence or Cherenkov emission from depths exceeding the location of the Bragg peak. To clarify this idea, we measured the luminescence images of water during the irradiations of protons in water with minimized parallax errors, and also simulated the produced light by the interactions of prompt gamma photons with water. We corrected the measured depth profiles of the luminescence images by subtracting the simulated distributions of the produced light by the interactions of prompt gamma photons in water. Corrections were also conducted using the estimated depth profiles of the light of the prompt gamma photons, as obtained from the off-beam areas of the luminescence images of water. With these corrections, we successfully obtained depth profiles that have almost identical distributions as the simulated dose distributions for protons. The percentage relative height of the Bragg peak with corrections to that of the simulation data increased to 94% from 80% without correction. Also, the percentage relative offset heights of the deeper part of the Bragg peak with corrections decreased to 0.2%-0.4% from 4% without correction. These results indicate that the luminescence imaging of water has potential for the dose distribution measurements for proton therapy dosimetry.

  7. 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)

  8. 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.

  9. 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

  10. 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

  11. Correlation between the local stress and the grain misorientation in the polycrystalline Al2O3 measured by near-field luminescence spectroscopy

    Science.gov (United States)

    Tomimatsu, Toru; Takigawa, Ryo

    2018-06-01

    Owing to its high spatial resolution, near-field spectroscopy is a useful method for sensing the stress in a narrow region of submicron order. Here, on the basis of the highly resolved images obtained by near-field luminescence spectroscopy, we propose a statistical method of analyzing grain anisotropy-induced stress in polycrystalline Al2O3. We focus on two characteristics of a spectra: the intensity ratio and peak shift of luminescence of two lines (R1 and R2) from Al2O3 to discuss crystal orientation and stress, respectively. By incorporating the concept of the crystal misorientation parameter using intensity ratio, an apparent correlation between the magnitude of stress and the misorientation is found. This correlation analysis provides an important insight for the investigation of local thermal stress in Al2O3.

  12. 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

  13. 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

  14. 8 nm nanodiamonds as markers for 2 photon excited luminescent microscopy

    International Nuclear Information System (INIS)

    Kharin, A; Rogov, A; Bonacina, L; Geloen, A; Lysenko, V

    2016-01-01

    Structural and luminescent properties of stable suspensions of fluorescent nanodiamonds were investigated. Measurement of the effective hydrodynamic radius yields particles less than 30 nm diameter, while the TEM measurements made on the same particles shows average diameter about 8 nm. It was found that NDs have relatively low toxicity. Upon incubation, 3T3-L1 cells spontaneously take up nanodiamonds that uniformly distribute in cells cytoplasm. The possibility of fluorescent imaging using both single ore two-photon excitation was shown. (paper)

  15. Vibrational bands of luminescent zinc(II)-octaethyl-porphyrin using a polarization-sensitive 'microcopic' multiplex CARS technique

    NARCIS (Netherlands)

    Otto, Cornelis; Voroshilov, A.; Voroshilov, Artemy; Kruglik, S.; Kruglik, S.G.; Greve, Jan

    2001-01-01

    Polarization-sensitive, multiplex coherent anti-Stokes Raman scattering (ps-MCARS) has been used to detect the vibrational bands of the highly luminescent zinc(II)-octaethylporphyrin (Zn-OEP). We show here that ps-MCARS can be used to measure the vibrational bands under resonant conditions.

  16. Probing luminescence centers in Na rich feldspar

    DEFF Research Database (Denmark)

    Prasad, Amit Kumar; Lapp, Torben; Kook, Myung Ho

    2016-01-01

    our understanding of the luminescence mechanisms and recombination sites, in a sample of Na rich plagioclase feldspar (oligoclase). Both the UV and violet–blue emissions show resonant excitations arising from a distribution of energy levels. We propose, contrary to the general understanding...

  17. Measurement of pO2 by luminescence lifetime spectroscopy: A comparative study of the phototoxicity and sensitivity of [Ru(Phen)3 ]2+ and PdTCPP in vivo.

    Science.gov (United States)

    Huntosova, Veronika; Gerelli, Emmanuel; Horvath, Denis; Wagnieres, Georges

    2017-05-01

    Dysfunctions in tissue metabolism can be detected at early stages by oxygen partial pressure (pO 2 ) measurement. The measurement of emission lifetimes offers very promising and non-invasive approach to estimate pO 2 in vivo. This study compares two extensively used oxygen sensors and assesses their in vivo oxygen sensitivity and phototoxic effect. Luminescence lifetime of Ru-polypyridyl complex and of Pd-porphyrin is measured in the Chick's Chorioallantoic Membrane (CAM) model with a dedicated optical fiber-based, time-resolved spectrometer. The Pd-porphyrin luminescence lifetimes measured in the CAM model exposed to different pO 2 levels are longer and have a broader dynamic range (10-100 μs) than those of Ru-polypyridyl complex (0.6-1 μs). The combined statistical analysis based on an estimate of the kurtosis and skewness, bootstrapping method and routine normality tests is performed. The indicators of the averages and signal to noise ratio stability are also calculated. The combination of several data processing allows selection of the better sensor for a given application. In particular, it is found that the advantage of Ru-polypyridyl complex over Pd-porphyrin is two-fold: i) Ru-polypyridyl complex datasets have consistently better statistical characteristics, ii) Ru-polypyridyl exhibits lower cytotoxicity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Comparison of temperature sensing of the luminescent upconversion and ZnCdS nanoparticles

    Science.gov (United States)

    Yanina, I. Yu.; Volkova, E. K.; Sagaidachnaya, E. A.; Konyukhova, J. G.; Kochubey, V. I.; Tuchin, V. V.

    2018-02-01

    The luminescence spectra of upconversion nanoparticles (UCNPs) and ZnCdS nanoparticles (ZnCdSNPs) were measured and analyzed in a wide temperature range: from room to human body and further to a hyperthermic temperature resulting in tissue morphology change. The results show that the luminescence signal of UCNPs and ZnCdSNPs placed within the tissue is reasonably good sensitive to temperature change and accompanied by phase transitions of lipid structures of adipose tissue. The most likely that the multiple phase transitions are associated with the different components of fat cells, such as phospholipids of cell membrane and lipids of fat droplets. In the course of fat cell heating, lipids of fat droplet first transit from a crystalline form to a liquid crystal form and then to a liquid form, which is characterized by much less scattering. The results of phase transitions of lipids were observed as the changes in the slope of the temperature dependence of the intensity of luminescence of the film with nanoparticles embedded into tissue. The obtained results confirm a high sensitivity of the luminescent UCNPs and ZnCdSNPs to the temperature variations within thin tissue samples and show a strong potential for the controllable tissue thermolysis.

  19. Non-mineralized fibrocartilage shows the lowest elastic modulus in the rabbit supraspinatus tendon insertion: measurement with scanning acoustic microscopy.

    Science.gov (United States)

    Sano, Hirotaka; Saijo, Yoshifumi; Kokubun, Shoichi

    2006-01-01

    The acoustic properties of rabbit supraspinatus tendon insertions were measured by scanning acoustic microscopy. After cutting parallel to the supraspinatus tendon fibers, specimens were fixed with 10% neutralized formalin, embedded in paraffin, and sectioned. Both the sound speed and the attenuation constant were measured at the insertion site. The 2-dimensional distribution of the sound speed and that of the attenuation constant were displayed with color-coded scales. The acoustic properties reflected both the histologic architecture and the collagen type. In the tendon proper and the non-mineralized fibrocartilage, the sound speed and attenuation constant gradually decreased as the predominant collagen type changed from I to II. In the mineralized fibrocartilage, they increased markedly with the mineralization of the fibrocartilaginous tissue. These results indicate that the non-mineralized fibrocartilage shows the lowest elastic modulus among 4 zones at the insertion site, which could be interpreted as an adaptation to various types of biomechanical stress.

  20. 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

  1. 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)

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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)

  7. 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)

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. Sample and plume luminescence in fast heavy ion induced desorption

    International Nuclear Information System (INIS)

    Tuszynski, W.; Koch, K.; Hilf, E.R.

    1996-01-01

    The luminescence arising in 252 Cf-fission fragment induced desorption events has been measured using the time-correlated single photon counting technique. Photons emitted from the sample have been guided from a plasma desorption ion source to a photodetector by an optical fibre. Spectra and decay functions have been obtained using thin layers of Coronene or POPOP as samples. The results are strongly dependent on the acceleration field applied for ion extraction. Approximately 10 photons per fission fragment have been produced when applying no accelerating voltage. The results clearly show that these photons come from radiative electronic relaxations of molecules in the solid sample. Considerably more photons per fission fragment have been produced when applying a positive acceleration voltage. The intensity increases almost linearly for acceleration fields below 10 kV/cm and saturates at a nearly 10-fold higher value when compared to no acceleration. The intensity is also affected by the homogeneity of the accelerating field. These additional photons are attributed to radiative electronic relaxations of desorbed neutral molecules in the plume excited by inelastic collisions with accelerated positive ions. No additional photons have been observed when extracting negative ions. The negative ions produced do obviously not hit and/or excite desorbed neutral molecules, presumably due to their specific desorption characteristics. The experimental data have been analyzed by comparing with the cw and time-resolved sample luminescence obtained by optical excitation. The findings demonstrate that valuable information on ion-solid interactions, on specific desorption quantities and on processes in the plume can be obtained by measuring and analyzing the luminescence induced by the impact of high energy primary ions. (orig.)

  14. 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.

  15. 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.

  16. 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)

  17. Luminescence properties of a nanoporous freshwater diatom.

    Science.gov (United States)

    Goswami, Bondita; Choudhury, Amarjyoti; Buragohain, Alak K

    2012-01-01

    Freshwater diatom frustules show special optical properties. In this paper we observed luminescence properties of the freshwater diatom Cyclotella meneghiniana. To confirm the morphological properties we present scanning electron microscopy (SEM) images. X-ray diffraction (XRD) studies were carried out to visualize the structural properties of the frustules, confirming that silica present in diatom frustules crystallizes in an α-quartz structure. Study of the optical properties of the silica frustules of diatoms using ultra-violet-visible (UV-vis) spectroscopy and photoluminescence spectroscopy confirmed that the diatom C. meneghiniana shows luminescence in the blue region of the electromagnetic spectrum when irradiated with UV light. This property of diatoms can be exploited to obtain many applications in day-to-day life. Also, using time-resolved photoluminescence spectroscopy (TRPL) it was confirmed that this species of diatom shows bi-exponential decay. Copyright © 2011 John Wiley & Sons, Ltd.

  18. 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;

  19. Polymorphism in promoter of SIX4 gene shows association with its transcription and body measurement traits in Qinchuan cattle.

    Science.gov (United States)

    Wei, Dawei; Raza, Sayed Haidar Abbas; Zhang, Jiupan; Gui, Linsheng; Rahman, Siddiq Ur; Khan, Rajwali; Hosseini, Seyed Mahdi; Kaleri, Hubdar Ali; Zan, Linsen

    2018-05-20

    The sine oculis homeobox homolog 4 (SIX4) gene belongs to the SIX gene family, which plays a critical role in muscle regeneration and early stages of ontogeny. This study aimed to detect promoter variations of bovine SIX4 genes in Qinchuan cattle, and to evaluate the effect of transcription regulations and body measurement traits. Quantitative real-time PCR (qPCR) results showed that the mRNA expression levels of SIX4 gene were found significantly highest in longissimus thoracis tissue and individual before attaining the stage of physiological maturity. Using sequencing technology on a total of 428 Qinchuan cattle, seven single nucleotide polymorphisms (SNPs) were identified in the promoter region of SIX4, and seven haplotypes representing 18 potential transcription factor compositions of polymorphic potential cis-acting elements. Association analysis indicated that the H 3 -H 3 diplotype performed greater withers height, chest depth, chest circumference, back fat thickness and ultrasound loin muscle area (P cattle. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. 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.

  1. X-ray excited optical luminescence (XEOL) and its application to porous silicon

    International Nuclear Information System (INIS)

    Hill, D.A.

    1998-09-01

    X-ray Excited Optical Luminescence (XEOL) is investigated as a local structural probe of the light-emitting sites in porous silicon. A detailed microscopic model of the XEOL process in porous silicon is proposed. A central aspect of the technique is an assessment of the spatial separation between the primary photoionisation event and subsequent optical radiative recombination. By constructing a Monte Carlo simulation of hot electron propagation in silicon using both elastic and inelastic scattering cross-sections, the mean minimum range of luminescence excitation can be calculated. This range is estimated as 546±1A for the silicon K-edge (∼ 1839eV), but is reduced to 8.9±0.1A for the silicon L 2,3 -edge (∼ 99eV). From known porous silicon properties, it is concluded that this mean minimum range is comparable to the actual range of excitation. Hence, more localised structural information may be obtained from L 2,3 -edge XEOL measurements. This important difference between the two spectra has been neglected in previous studies. Simultaneous measurements of the XEOL and total electron yield (TEY) x-ray absorption spectra (XAS) have been conducted at both the silicon K-edge and L 2,3 -edge for various porous silicon samples and related materials. Measurements have been conducted at the Si K-edge on a rapid thermally oxidised (RTO) porous silicon sample. XEOL spectra yield two distinct luminescence bands in the visible region. From multi-bunch wavelength-selective XEOL measurements, it is concluded that there are blue luminescent defective silica sites together with a red luminescent site originating from silicon-like material. The spectral time decay curve under pulsed x-ray excitation gives two distinct decay components; one fast in the range of a few nanoseconds and the other slow in the range of microseconds. Time-resolved XEOL measurements in single-bunch mode show that the fast band mirrors the blue wavelength XEOL whereas the slow band correlates with the

  2. 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

  3. 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.

  4. Thermal History Using Microparticle Trap Luminescence

    Science.gov (United States)

    2012-06-01

    the size and shape of bacterial or viral agents and dispersed in a burst vessel . After the test, luminescence from the microparticles is measured to...platinum resistor sputtered on 1 nm adhesion layer of chrome, in turn on a 200nm LPCVD nitride; silicon wet -etching makes this a platform suspended...increased to 500°C until combustion occurred (- 7 min). The remaining powder was collected, crushed in a agate mortar, and annealed (typically at 900

  5. Functional measures show improvements after a home exercise program following supervised balance training in older adults with elevated fall risk.

    Science.gov (United States)

    Tisher, Kristen; Mann, Kimberly; VanDyke, Sarah; Johansson, Charity; Vallabhajosula, Srikant

    2018-03-05

    Supervised balance training shows immediate benefit for older adults at fall risk. The long-term effectiveness of such training can be enhanced by implementing a safe and simple home exercise program (HEP). We investigated the effects of a12-week unsupervised HEP following supervised clinic-based balance training on functional mobility, balance, fall risk, and gait. Six older adults with an elevated fall risk obtained an HEP and comprised the HEP group (HEPG) and five older adults who were not given an HEP comprised the no HEP group (NoHEPG). The HEP consisted of three static balance exercises: feet-together, single-leg stance, and tandem. Each exercise was to be performed twice for 30-60 s, once per day, 3 days per week for 12 weeks. Participants were educated on proper form, safety, and progression of exercises. Pre- and post-HEP testing included Berg Balance Scale (BBS), Timed Up and Go, Short Physical Performance Battery (SPPB) assessments, Activities-Balance Confidence, Late-Life Functional Disability Instrument and instrumented assessments of balance and gait (Limits of Stability, modified Clinical Test of Sensory Interaction on Balance, Gait). A healthy control group (HCG; n = 11) was also tested. For most of the measures, the HEPG improved to the level of HCG. Though task-specific improvements like BBS and SPPB components were seen, the results did not carry over to more dynamic assessments. Results provide proof of concept that a simple HEP can be independently implemented and effective for sustaining and/or improving balance in older adults at elevated fall-risk after they have undergone a clinic-based balance intervention.

  6. 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.

  7. The double luminescence of Color Centers

    International Nuclear Information System (INIS)

    Baldacchini, Giuseppe

    2015-01-01

    An experiment on the luminescence of Color Centers (CCs) carried out in 1987 at the ENEA Laboratories in Frascati had a negative result, but subsequent investigations showed that it was not a failure but rather a discovery of a new phenomenon. Since the coming of lasers, CCs in alkali halides have been successfully used as optically active materials, in particular FA Centers. One of these centers, well known for its medium infrared laser emission at 77 K, cooled further to 2 K emitted in the near infrared and without laser effect. Further investigations showed that the double luminescence was a fundamental property unknown until that time. This important discovery was achieved in Frascati because of the existence since 1973 of a solid and extensive expertise in the field of CCs, which continued over time and later on applied to the modern miniaturized photonic devices [it

  8. Excitonic effects in the luminescence of quantum wells

    International Nuclear Information System (INIS)

    Deveaud, B.; Kappei, L.; Berney, J.; Morier-Genoud, F.; Portella-Oberli, M.T.; Szczytko, J.; Piermarocchi, C.

    2005-01-01

    We report on the origin of the excitonic luminescence in quantum wells. This study is carried out by time-resolved photoluminescence experiments performed on a very high-quality InGaAs quantum well sample in which the photoluminescence contributions at the energy of the exciton and at the band edge can be clearly separated and traced over a broad range of times and densities. This allows us to compare the two conflicting theoretical approaches to the question of the origin of the excitonic luminescence in quantum wells: the model of the exciton population and the model of the Coulomb correlated plasma. We measure the exciton formation time and we show the fast exciton formation and its dependence with carrier density. We are also able to give the boundaries of the Mott transition in our system, and to show the absence of observable renormalization of the gap below the onset of this transition. We detail the characteristics of the trion formation and evidence the possible formation of both positive and negative trions in the absence of any resident free carrier populations

  9. Luminescence dating in archaeology

    International Nuclear Information System (INIS)

    Wintle, A.G.

    2001-01-01

    Thermoluminescence (TL) dating is routinely applied to burnt lithic material. Simple fires are capable of enabling stones weighing a few hundred grams to reach 450 o C, thus zeroing the TL signal. TL dates have been obtained for Upper and Lower Paleolithic sites in Europe and the Near East. TL dating continues to be used for dating pottery and for authentification of ceramic works of art. Some recent studies report the use of optically stimulated luminescence (OSL) (also know as photoluminescence) for dating very small samples of quartz, e.g. from small pieces of pottery or frm metallurgical slag The major recent advance has been in the development of a reliable laboratory procedure for using the OSL signal from quartz to obtain the past radiation exposure. The quartz OSL signal is extremely sensitive to light and is reduced to a negligible level on exposure to direct sunlight for radionuclides during burial, signal to date san.sized quartz grains extracted from sediments, The OSL signal is stimulated by 470 nm light from emitting diodes and the detected using flirters centred on 340 nm A similar signal can be obtained from feldspar grain when are exposed to infrared wavelengths around 880 nm. The infrared stimulated luminescence (IRSL) signals is also rapidly depleted by exposure to sunlight, and dating of colluvial deposits from archaeological sites has been reported

  10. Preparation and luminescence properties of Ca3(VO4)2: Eu3+, Sm3+ phosphor for light-emitting diodes

    International Nuclear Information System (INIS)

    Huang Jiaping; Li Qiuxia; Chen Donghua

    2010-01-01

    Rare-earth ions co-activated red phosphors Ca 3 (VO 4 ) 2 : Eu 3+ , Sm 3+ were synthesized by modified solid-state reactions. The samples were characterized by X-ray powder diffractometer (XRD), energy-dispersive X-ray spectrometer (EDS), transmission electron microscopy (TEM) and luminescence spectrometer (LS). The results showed that the Eu-Sm system exhibits higher emission intensity than those of the Eu single-doped system and Sm separate-doped system under blue light. Samarium (III) ions are effective in broadening and strengthening absorptions around 467 nm. Furthermore, they exhibit enhanced luminescence emission. Luminescent measurements showed that the phosphors can be efficiently excited by ultraviolet (UV) to visible region, emitting a red light with a peak wavelength of 616 nm. The material has potential application as a phosphor for light-emitting diodes (LEDs).

  11. Characterization of the proton irradiation induced luminescence of materials and application in radiation oncology dosimetry

    Science.gov (United States)

    Darafsheh, Arash; Zhang, Rongxiao; Kassaee, Alireza; Finlay, Jarod C.

    2018-03-01

    Visible light generated as the result of interaction of ionizing radiation with matter can be used for radiation therapy quality assurance. In this work, we characterized the visible light observed during proton irradiation of poly(methyl methacrylate) (PMMA) and silica glass fiber materials by performing luminescence spectroscopy. The spectra of the luminescence signal from PMMA and silica glass fibers during proton irradiation showed continuous spectra whose shape were different from that expected from Čerenkov radiation, indicating that Čerenkov radiation cannot be the responsible radioluminescence signal. The luminescence signal from each material showed a Bragg peak pattern and their corresponding proton ranges are in agreement with measurements performed by a standard ion chamber. The spectrum of the silica showed two peaks at 460 and 650 nm stem from the point defects of the silica: oxygen deficiency centers (ODC) and non-bridging oxygen hole centers (NBOHC), respectively. The spectrum of the PMMA fiber showed a continuous spectrum with a peak at 410 nm whose origin is connected with the fluorescence of the PMMA material. Our results are of interest for various applications based on imaging radioluminescent signal in proton therapy and will inform on the design of high-resolution fiber probes for proton therapy dosimetry.

  12. Dependence on liquid temperature and purity of light emission characteristics in single cavitation bubble luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Barbaglia, Mario O; Bonetto, Fabian J [Consejo Nacional de Investigaciones Cientificas y Tecnicas and Instituto Balseiro, Centro Atomico Bariloche, Av. Bustillo 9500, CP8400, Rio Negro (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, Instituto Balseiro, and Comision Nacional de Energia Atomica, Laboratorio de Cavitacion y Biotecnologia, Centro Atomico Bariloche, Av. Bustillo 9500, CP8400, Rio Negro (Argentina)

    2004-02-15

    We produced single bubbles in water using a visible pulsed laser and studied the characteristics of the light emitted during the bubble collapse time as a function of the water temperature for different water purity values. The water temperature ranged from freezing point (0 deg. C) to near boiling. We measured the luminescence pulse for the mentioned temperature range at various purity values. We also obtained the average bubble lifetime and the average luminescence pulse emitted as a function of water temperature. The main conclusion was that the luminescence can be modified by the water quality and by the water temperature. Maximum luminescence was obtained near the water freezing point.

  13. Dependence on liquid temperature and purity of light emission characteristics in single cavitation bubble luminescence

    International Nuclear Information System (INIS)

    Barbaglia, Mario O.; Bonetto, Fabian J.

    2004-01-01

    We produced single bubbles in water using a visible pulsed laser and studied the characteristics of the light emitted during the bubble collapse time as a function of the water temperature for different water purity values. The water temperature ranged from freezing point (0 deg. C) to near boiling. We measured the luminescence pulse for the mentioned temperature range at various purity values. We also obtained the average bubble lifetime and the average luminescence pulse emitted as a function of water temperature. The main conclusion was that the luminescence can be modified by the water quality and by the water temperature. Maximum luminescence was obtained near the water freezing point

  14. Temperature dependent luminescence Cr3+doped GdAl3(BO3)4 and YAl3(BO3)4

    NARCIS (Netherlands)

    Malysa, B.; Meijerink, A; Jüstel, Thomas

    Chromium activated YAl3(BO3)4 (YAB) and GdAl3(BO3)4 (GAB) were synthesized and show efficient broad band near infrared emission under excitation in the UV, blue and orange spectral regions. Temperature dependent luminescence measurements for GAB:1%Cr3+ and YAB:1%Cr3+ reveal high quenching

  15. A Radiation Dosimetry Method Using Pulsed Optically Stimulated Luminescence

    International Nuclear Information System (INIS)

    Akselrod, M.S.; McKeever, S.W.S.

    1999-01-01

    A method for the determination of absorbed radiation dose is described based on pulsed optically stimulated luminescence (POSL). The method relies upon the stimulation of an irradiated sample with a train of light pulses from a suitable light source (e.g. a laser) using a wavelength which is within the range of wavelengths corresponding to the radiation-induced optical absorption in the irradiated sample. The subsequent emitted light, due to the detrapping of trapped charges and their subsequent recombination with charge of the opposite sign, is synchronously detected in the period between each stimulation pulse. The total luminescence is summed over the desired number of stimulation pulses and this forms the measured POSL signal. By monitoring the emitted light only in the period between stimulation pulses one can reduce the optical filtering required to discriminate between the stimulation light and the emission light; in this way a high measurement efficiency, and, therefore, a high radiation sensitivity (luminescence intensity per unit absorbed dose) is achieved. Key parameters in the method are the intrinsic luminescence lifetime for the material being used as the luminescent detector, the width of the optical stimulation pulse, and the period between pulses. For optimum operation the measurement parameters should be such that both the pulse width and the time between pulses are much less than the luminescence lifetime. By appropriate choice of the power of the optical stimulation, the frequency of the stimulation pulses, and the total stimulation period, one can also re-measure the absorbed dose several times. In this way, a re-read capability is available with the procedure. The method is illustrated using light from a 2nd-harmonic Nd:YAG laser, with irradiated, anion-deficient aluminium oxide as the luminescent detector material. (author)

  16. 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.

  17. Luminescence studies of rare earth doped dosimeters

    International Nuclear Information System (INIS)

    Karali, T.

    1999-10-01

    The main objective of this thesis has been to address the applications and fundamentals of thermoluminescence (TL) and to contribute to existing knowledge about TL mechanisms in materials which are applied as radiation dosimeters. This issue has been explored for a long time but the mechanisms lack completeness and certainty. TL, Radioluminescence (RL) and Radio-thermoluminescence (RLTL) measurements have been conducted on a high sensitivity TL spectrometer both at low (30-290 K) and high (25-400 deg. C) temperatures, and different heat treatments (furnace and laser) were conducted in order to study the possible impurity clustering which changes the TL spectra and efficiency of the dosimeters. Studies have been based on three different host structure, namely sulphate, borates and zircon. The spectra of calcium sulphate samples doped with Tm 3+ and Dy 3+ at different concentration were examined using TL, RL and RLTL. Similar procedures were applied to the borate samples. Modifications of the material by thermal treatments convert the state of dispersion of the rare earth ions between isolated, pair or defect clusters, which alter the dosimeter efficiency. In some cases, modified geometries are detectable by movement of the line emissions such as for quenched samples which are attributable to new microcrystal line phases. The study of co-doped samples showed unequivocal evidence of a glow peak displacement of the two dopants within a single sample. This result supports the new view that RE 3+ ions could form part of a complex defect acting as both charge trap and recombination centres. Pulsed laser heating with a UV laser changed the glow curve shape and lead to strong signals. The detailed mechanisms for this process are discussed. The RL and TL spectra of synthetic zircon crystals doped with different RE 3+ ions (Pr, Sm, Eu, Gd, Ho, Dy, Er, and Yb) and phosphorus are reported. Even though there is some intrinsic emission from the host lattice the major signals are

  18. Agglomeration of Luminescent Porous Silicon Nanoparticles in Colloidal Solutions.

    Science.gov (United States)

    Herynková, Kateřina; Šlechta, Miroslav; Šimáková, Petra; Fučíková, Anna; Cibulka, Ondřej

    2016-12-01

    We have prepared colloidal solutions of clusters composed from porous silicon nanoparticles in methanol, water and phosphate-buffered saline (PBS). Even if the size of the nanoclusters is between 60 and 500 nm, due to their highly porous "cauliflower"-like structure, the porous silicon nanoparticles are composed of interconnected nanocrystals having around 2.5 nm in size and showing strong visible luminescence in the orange-red spectral region (centred at 600-700 nm). Hydrophilic behaviour and good solubility of the nanoclusters in water and water-based solutions were obtained by adding hydrogen peroxide into the etching solution during preparation and 16 min long after-bath in hydrogen peroxide. By simple filtration of the solutions with syringe filters, we have extracted smaller nanoclusters with sizes of approx. 60-70 nm; however, these nanoclusters in water and PBS solution (pH neutral) are prone to agglomeration, as was confirmed by zeta potential measurements. When the samples were left at ambient conditions for several weeks, the typical nanocluster size increased to approx. 330-400 nm and then remained stable. However, both freshly filtered and aged samples (with agglomerated porous silicon nanoparticles) of porous silicon in water and PBS solutions can be further used for biological studies or as luminescent markers in living cells.

  19. Unique Chiral Interpenetrating d-f Heterometallic MOFs as Luminescent Sensors.

    Science.gov (United States)

    Wu, Zhi-Lei; Dong, Jie; Ni, Wei-Yan; Zhang, Bo-Wen; Cui, Jian-Zhong; Zhao, Bin

    2015-06-01

    One novel three-dimensional (3D) 3d-4f metal-organic framework (MOF), [TbZn(L)(CO3)2(H2O)]n (1) [HL = 4'-(4-carboxyphenyl)-2,2':6',2″-terpyridine], has been successfully synthesized and structurally characterized. Structural analysis shows that compound 1 features a unique chiral interpenetrating 3D framework for the first time. The resulting crystals of 1 are composed of enantiomers 1a (P41) and 1b (P43), as was clearly confirmed by the crystal structure and the corresponding circular dichroism (CD) analyses of eight randomly selected crystals. The investigations on CD spectra based on every single crystal clearly assigned the Cotton effect signals. The powder X-ray diffraction measurement of 1 after being immersed in common solvents reveals that 1 possess excellent solvent stability. Furthermore, luminescent studies imply that 1 displays highly selective luminescent sensing of aldehydes, such as formol, acetaldehyde, and propanal.

  20. Luminescence properties of oxide films formed by anodization of aluminum in 12-tungstophosphoric acid

    International Nuclear Information System (INIS)

    Stojadinovic, S.; Vasilic, R.; Petkovic, M.; Nedic, Z.; Kasalica, B.; Belca, I.; Zekovic, Lj.

    2010-01-01

    In this paper, we have investigated luminescence properties of oxide films formed by anodization of aluminum in 12-tungstophosphoric acid. For the first time we have measured weak luminescence during anodization of aluminum in this electrolyte (so-called galvanoluminescence GL) and showed that there are wide GL bands in the visible region of the spectrum and observed two dominant spectral peaks. The first one is at about 425 nm, and the second one shifts with anodization voltage. As the anodization voltage approaches the breakdown voltage, a large number of sparks appear superimposed on the anodic GL. Several intensive band peaks were observed under breakdown caused by electron transitions in W, P, Al, O, H atoms. Furthermore, photoluminescence (PL) of anodic oxide films and anodic-spark formed oxide coatings were performed. In both cases wide PL bands in the range from 320 nm to 600 nm were observed.

  1. Highly sensitive time resolved singlet oxygen luminescence detection using LEDs as the excitation source

    International Nuclear Information System (INIS)

    Hackbarth, S; Schlothauer, J; Preuss, A; Röder, B

    2013-01-01

    For the first time singlet oxygen luminescence kinetics in living cells were detected at high precision using LED light for excitation. As LED technology evolves, the light intensity emitted by standard LEDs allows photosensitized singlet oxygen luminescence detection in solution and cell suspensions. We present measurements superior to those of most actual laser powered setups regarding precision of singlet oxygen kinetics in solutions and cell suspensions. Data presented here show that LED based setups allow the determination of the photosensitizer triplet and singlet oxygen decay times in vitro with an accuracy of 0.1 μs. This enables monitoring of the photosensitizer efficiency and interaction with the cellular components using illumination doses small enough not to cause cell death. (letter)

  2. Luminescence of UO2+sub(2(aq)) + FU+sub(2(aq)) and evidence for the formation of a new inorganic radiative exciplex in aqueous solution

    International Nuclear Information System (INIS)

    Deschaux, M.; Marcantonatos, M.D.

    1981-01-01

    Steady-state and time-resolved luminescence measurements, as well as decays of excited UO 2 2+ + FUO 2 + in aqueous solution, show the formation of a radiative exciplex, resulting from the interaction of *FUO 2 H + with UO 2 2+ , similarly to the *U 2 O 4 H 4+ exciplex already reported. Lifetimes and evaluations of the luminescence yields of the *UO 2 2+ , *FUO 2 + and of the exciplex of probable *(O(F)UOHOUO) 3+ composition, are given. The overall heat of the exciplex formation is estimated. (author)

  3. Persistent luminescence nanothermometers

    Science.gov (United States)

    Martín Rodríguez, Emma; López-Peña, Gabriel; Montes, Eduardo; Lifante, Ginés; García Solé, José; Jaque, Daniel; Diaz-Torres, Luis Armando; Salas, Pedro

    2017-08-01

    Persistent phosphorescence nanoparticles emitting in the red and near-infrared spectral regions are strongly demanded as contrast nanoprobes for autofluorescence free bioimaging and biosensing. In this work, we have developed Sr4Al14O25:Eu2+, Cr3+, Nd3+ nanopowders that produce persistent red phosphorescence peaking at 694 nm generated by Cr3+ ions. This emission displays temperature sensitivity in the physiological temperature range (20-60 °C), which makes these nanoparticles potentially useful as fluorescence (contactless) nanothermometers operating without requiring optical excitation. Nd3+ ions, which act as shallow electron traps for the red Cr3+ persistent emission, also display infrared emission bands, extending the fluorescence imaging capability to the second biological window. This unique combination of properties makes these nanoparticles multifunctional luminescent probes with great potential applications in nanomedicine.

  4. 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.

  5. 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)

  6. Process for producing a self luminescent material

    Energy Technology Data Exchange (ETDEWEB)

    Abe, E

    1962-01-28

    A self luminescent material is produced by a process comprising applying a hydroxide or fluoride of promethium-147 suspended in a medium of paraffinic acid to the surface of a fluorescent body. Promethium-147 decays with a half-life of 2.6 years and emits beta-rays but not alpha- and gamma-rays so that it is suitable for manufacturing self luminescent materials. A chloride of promethium-147 cannot be employed because its structure is destroyed by acids. Although fluorides and hydroxides of promethium-147 are difficult to mix with the fluorescent body material, they become mixable when paraffinic acids containing from 12 to 20 carbon atoms, (for example, steric acid, palmitic acid and margaric acid) are used as a medium. In embodiments, the self luminescent materials are prepared by either neutralization of a promethium-147 chloride solution having a specific radioactivity of 1.2 c/cc. with an ammonium hydroxide solution to form gelatinous hydroxide, or the reaction of a promethium-147 chloride solution with H/sub 2/SiF/sub 6/ by heating at 80/sup 0/C to form a fluoride of promethium-147. The products have a specific radioactivity of 8 to 12 mc/g. These products are suspended in vehicles of polystyrene and methacrylic resin to produce the self luminescent coating materials. Tests show that the initical brightness is comparatively high, the decreasing rate of brightness is small, no blackening effects by alpha-rays occur and costs are low. The brightness of the coating containing promethium-147 is 82-85 after 5 days, 100-105 after 100 days and 82-92 after 180 days. With respect to the coating containing radium the values are 31-70 after 5 days, 28-49 after 100 days and 19-31 after 180 days.

  7. Depth profilometric case studies in caries diagnostics of human teeth using modulated laser radiometry and luminescence

    Science.gov (United States)

    Jeon, Raymond J.; Mandelis, Andreas; Abrams, Stephen H.

    2003-01-01

    Simultaneous measurements from human teeth of photothermal radiometric (PTR) and luminescence (LM) signals induced by an intensity modulated laser have been performed to assess the feasibility of detecting deep lesions and near-surface cracks, to examine the effects of varying enamel thicknesses, the presence of fillings, and stains on the surface of teeth. A commercial dc luminescence monitoring instrument (DIAGNOdent by KaVo) was also used to examine a set of teeth for comparison purposes with PTR and LM. PTR amplitude signals from carious regions and from thin enamel were higher than those from healthy regions and thicker enamel. A crack produces a peak in the PTR amplitude scan, as well as a sudden change in the luminescence amplitude at the corresponding point. At low frequencies (5 Hz), the PTR amplitude showed high sensitivity to a deep (about 2 mm) lesion, while at high frequencies (700 Hz) it was more sensitive to surface cracks. It was concluded that by selecting proper modulation frequencies of the laser, measurements of PTR and LM signals could be used as a dental diagnostic technique with a small, inexpensive, low-power (<30 mW) semiconductor laser as a light source emitting in the optical window range of hard tissue (650-1000 nm).

  8. The influence of vacuum and annealing on the visible luminescence in ZnO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    P R, Chithira; Theresa John, Teny, E-mail: teny@goa.bits-pilani.ac.in

    2017-05-15

    The ZnO nanoparticles synthesized by a simple solution based chemical bath deposition method were characterized using different experimental techniques. Photoluminescence (PL) studies were performed in ambient as well as in vacuum conditions. The emission spectra exhibit two bands corresponding to UV emission at 380 nm and a wide visible luminescence centered at 571 nm due to surface defects in ambient conditions. Under vacuum condition, the spectra show a reduction in the intensity of the wide visible luminescence and an enhancement in the UV emission. These nanoparticles were annealed at high temperatures in air. The wide visible luminescence remains at the same intensity in both ambient and in vacuum condition for the annealed samples indicating that some of the surface adsorbed defects are removed due to annealing. Fourier Transform Infrared Spectroscopy (FTIR) and Electron Spin Resonance (ESR) results reveal the presence of [OH{sup -}] related groups on the surface of the samples. An analysis of the O1s peak in ZnO using X-ray Photoelectron Spectroscopy (XPS) measurement confirms the presence of intrinsic defects such as oxygen related vacancies and adsorbed oxygen species in the sample. Our investigation shows that the green emission observed in ZnO samples is primarily due to oxygen vacancies.

  9. The influence of vacuum and annealing on the visible luminescence in ZnO nanoparticles

    International Nuclear Information System (INIS)

    P R, Chithira; Theresa John, Teny

    2017-01-01

    The ZnO nanoparticles synthesized by a simple solution based chemical bath deposition method were characterized using different experimental techniques. Photoluminescence (PL) studies were performed in ambient as well as in vacuum conditions. The emission spectra exhibit two bands corresponding to UV emission at 380 nm and a wide visible luminescence centered at 571 nm due to surface defects in ambient conditions. Under vacuum condition, the spectra show a reduction in the intensity of the wide visible luminescence and an enhancement in the UV emission. These nanoparticles were annealed at high temperatures in air. The wide visible luminescence remains at the same intensity in both ambient and in vacuum condition for the annealed samples indicating that some of the surface adsorbed defects are removed due to annealing. Fourier Transform Infrared Spectroscopy (FTIR) and Electron Spin Resonance (ESR) results reveal the presence of [OH - ] related groups on the surface of the samples. An analysis of the O1s peak in ZnO using X-ray Photoelectron Spectroscopy (XPS) measurement confirms the presence of intrinsic defects such as oxygen related vacancies and adsorbed oxygen species in the sample. Our investigation shows that the green emission observed in ZnO samples is primarily due to oxygen vacancies.

  10. Charged defects during alpha-irradiation of actinide oxides as revealed by Raman and luminescence spectroscopy

    International Nuclear Information System (INIS)

    Mohun, R.; Desgranges, L.; Léchelle, J.; Simon, P.; Guimbretière, G.; Canizarès, A.; Duval, F.; Jegou, C.; Magnin, M.; Clavier, N.; Dacheux, N.; Valot, C.; Vauchy, R.

    2016-01-01

    We have recently evidenced an original Raman signature of alpha irradiation-induced defects in UO 2 . In this study, we aim to determine whether the same signature also exists in different actinide oxides, namely ThO 2 and PuO 2 . Sintered UO 2 and ThO 2 were initially irradiated with 21 MeV He 2+ ions using a cyclotron device and were subjected to an in situ luminescence experiment followed by Raman analysis. In addition, a PuO 2 sample which had accumulated self-irradiation damage due to alpha particles was investigated only by Raman measurement. Results obtained for the initially white ThO 2 showed that a blue color appeared in the irradiated areas as well as luminescence signals during irradiation. However, Raman spectroscopic analysis showed the absence of Raman signature in ThO 2 . In contrast, the irradiated UO 2 and PuO 2 confirmed the presence of the Raman signature but no luminescence peaks were observed. The proposed mechanism involves electronic defects in ThO 2 , while a coupling between electronic defects and phonons is required to explain the Raman spectra for UO 2 and PuO 2 .

  11. The influence of silver-ion doping using ion implantation on the luminescence properties of Er–Yb silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Stanek, S., E-mail: stanislav.stanek@vscht.cz [Department of Inorganic Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Technicka 5, 16628 Prague (Czech Republic); Nekvindova, P.; Svecova, B.; Vytykacova, S.; Mika, M. [Department of Inorganic Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Technicka 5, 16628 Prague (Czech Republic); Oswald, J. [Institute of Physics, Academy of Science of the Czech Republic, Cukrovarnicka 10/112, 162 00 Prague (Czech Republic); Mackova, A.; Malinsky, P. [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, 25068 Rez (Czech Republic); Department of Physics, Faculty of Science, J.E. Purkinje University, Ceske mladeze 8, 40096 Usti nad Labem (Czech Republic); Spirkova, J. [Department of Inorganic Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Technicka 5, 16628 Prague (Czech Republic)

    2016-03-15

    A set of zinc-silicate glasses with different ratios of erbium and ytterbium was fabricated. To achieve Ag-rich thin films in a sub-surface layer, ion-implantation technique at an energy of 1.2 MeV and 1.7 MeV with a fluence of 1 × 10{sup 16} cm{sup −2} was used. Post-implantation annealing was also applied. Changes in the spectroscopic and lasing properties of erbium ions as a function of implantation fluence of silver were studied with the aim to assess the positive effect of silver as a sensitiser of erbium luminescence. Therefore, absorption spectra in the visible range as well as luminescence spectra in the near-infrared range were measured and partially also the {sup 4}I{sub 11/2}–{sup 4}I{sub 15/2} transition of the erbium ion was studied. The results showed that silver positively influenced luminescence intensity at 1530 nm by increasing it almost three times. The biggest increase was achieved in glass with the highest concentration of erbium. Luminescence lifetime was not significantly influenced by the presence of silver and still remained around 10 ms.

  12. 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.

  13. Measure, Then Show: Grasping Human Evolution Through an Inquiry-Based, Data-driven Hominin Skulls Lab.

    Directory of Open Access Journals (Sweden)

    Chris N Bayer

    Full Text Available Incomprehension and denial of the theory of evolution among high school students has been observed to also occur when teachers are not equipped to deliver a compelling case also for human evolution based on fossil evidence. This paper assesses the outcomes of a novel inquiry-based paleoanthropology lab teaching human evolution to high-school students. The inquiry-based Be a Paleoanthropologist for a Day lab placed a dozen hominin skulls into the hands of high-school students. Upon measuring three variables of human evolution, students explain what they have observed and discuss findings. In the 2013/14 school year, 11 biology classes in 7 schools in the Greater New Orleans area participated in this lab. The interviewed teacher cohort unanimously agreed that the lab featuring hominin skull replicas and stimulating student inquiry was a pedagogically excellent method of delivering the subject of human evolution. First, the lab's learning path of transforming facts to data, information to knowledge, and knowledge to acceptance empowered students to themselves execute part of the science that underpins our understanding of deep time hominin evolution. Second, although challenging, the hands-on format of the lab was accessible to high-school students, most of whom were readily able to engage the lab's scientific process. Third, the lab's exciting and compelling pedagogy unlocked higher order thinking skills, effectively activating the cognitive, psychomotor and affected learning domains as defined in Bloom's taxonomy. Lastly, the lab afforded students a formative experience with a high degree of retention and epistemic depth. Further study is warranted to gauge the degree of these effects.

  14. Measure, Then Show: Grasping Human Evolution Through an Inquiry-Based, Data-driven Hominin Skulls Lab.

    Science.gov (United States)

    Bayer, Chris N; Luberda, Michael

    2016-01-01

    Incomprehension and denial of the theory of evolution among high school students has been observed to also occur when teachers are not equipped to deliver a compelling case also for human evolution based on fossil evidence. This paper assesses the outcomes of a novel inquiry-based paleoanthropology lab teaching human evolution to high-school students. The inquiry-based Be a Paleoanthropologist for a Day lab placed a dozen hominin skulls into the hands of high-school students. Upon measuring three variables of human evolution, students explain what they have observed and discuss findings. In the 2013/14 school year, 11 biology classes in 7 schools in the Greater New Orleans area participated in this lab. The interviewed teacher cohort unanimously agreed that the lab featuring hominin skull replicas and stimulating student inquiry was a pedagogically excellent method of delivering the subject of human evolution. First, the lab's learning path of transforming facts to data, information to knowledge, and knowledge to acceptance empowered students to themselves execute part of the science that underpins our understanding of deep time hominin evolution. Second, although challenging, the hands-on format of the lab was accessible to high-school students, most of whom were readily able to engage the lab's scientific process. Third, the lab's exciting and compelling pedagogy unlocked higher order thinking skills, effectively activating the cognitive, psychomotor and affected learning domains as defined in Bloom's taxonomy. Lastly, the lab afforded students a formative experience with a high degree of retention and epistemic depth. Further study is warranted to gauge the degree of these effects.

  15. 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.

  16. Testing the application of quartz and feldspar luminescence dating to MIS 5 Japanese marine deposits

    DEFF Research Database (Denmark)

    Thiel, Christine; Tsukamoto, Sumiko; Tokuyasu, Kayoko

    2015-01-01

    The applicability of both quartz and feldspar luminescence dating was tested on twenty-five samples from a marine succession now forming a coastal cliff at Oga Peninsula, Honshu Island, Japan. The quartz optically stimulated luminescence (OSL) signal shows thermal instability and linear modulated...

  17. 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

  18. An attempt at determining Des of glacial sediments using different luminescence methods

    International Nuclear Information System (INIS)

    Ou Xianjiao; Lai Zhongping; Zeng Lanhua

    2013-01-01

    Background: Absolute dating is the key technical issue of Quaternary glacial research. Optically stimulated luminescence (OSL) has been increasingly applied to Quaternary glacial dating in recent years. However, problems such as insufficient bleaching, low luminescence sensitivity, high thermal transfer effect, etc, still remain. Purpose: In order to investigate the applicability of equivalent dose (D e ) determination of glacial sediments by different OSL methods, six samples were collected from the Yingpu Valley of eastern Qinghai-Tibetan Plateau (two samples from modern glacial sediments, three from moraines and glacial terrace attributed to Neoglacial and one from a moraine attributed to the last glaciation). Methods: The D e s were determined by SAR combined SGC technique, using three methods: quartz large aliquot (6 mm) BSL, small aliquot (2/3 mm) BSL and polymineral IRSL. Results: D e s determined by SGC are consistent with D e s determined by SAR protocol. Comparison of three methods shows that IRSL D e >large aliquot BSL D e >small aliquot BSL D e . D e s of polymineral IRSL are obviously higher than quartz BSL. Conclusions: It is obviously that feldspar is more difficult to reset than quartz, thus is not suitable for dating glacial sediments in this region. Quartz large aliquot method is suitable for well bleached glacial samples. Due to the low luminescence sensitivity of quartz, small aliquot method showed poor luminescence characteristics. Moreover, this method cannot distinguish the poor bleached grains in this measurement. However, it is possible that quartz small aliquot, even single grain method could be used to date older or brighter glacial samples. More works are required to solve the problems we have encountered in dating low sensitivity glacial sediments. (authors)

  19. Luminescence properties of Yb:Nd:Tm:KY{sub 3}F{sub 10} nanophosphor and thermal treatment effects

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Laércio, E-mail: lgomes@ipen.br [Centro de Lasers e Aplicações, Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, Butantã, P.O. Box 11049, São Paulo, SP o5422-970 (Brazil); Linhares, Horácio Marconi da Silva M.D. [Centro de Lasers e Aplicações, Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, Butantã, P.O. Box 11049, São Paulo, SP o5422-970 (Brazil); Ichikawa, Rodrigo Uchida; Martinez, Luis Gallego [Departamento de Ciências dos Materiais, Instituto de Pesquisas Energéticas e Nucleares (Brazil); Ranieri, Izilda Marcia [Centro de Lasers e Aplicações, Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, Butantã, P.O. Box 11049, São Paulo, SP o5422-970 (Brazil)

    2015-01-15

    In this work, we present the spectroscopic properties of KY{sub 3}F{sub 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 {sup 1}G{sub 4} (Tm{sup 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{sup 3+} to Tm{sup 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 {sup 1}G{sub 4} level luminescence kinetic of Tm{sup 3+} in Yb/Nd/Tm system revealed that the luminescence efficiency ({sup 1}G{sub 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{sub 1}) and (Nd×Yb×Tm) (Up{sub 2}) upconversion processes to the {sup 1}G{sub 4} luminescence are 33% (Up{sub 1}) and 67% for Up{sub 2}. Up{sub 2} process represented by Nd{sup 3+} ({sup 4}F{sub 3/2})→Yb{sup 3+} ({sup 2}F{sub 7/2}) followed by Yb{sup 3+} ({sup 2}F{sub 5/2})→Tm ({sup 3}H{sub 4})→Tm{sup 3+} ({sup 1}G{sub 4}) was previously reported as the main mechanism to produce the blue luminescence in Yb:Nd:Tm:YLiF{sub 4} and KY{sub 3}F{sub 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

  20. Goldenphilicity: Luminescent gold compounds

    International Nuclear Information System (INIS)

    Sansores, L.E.

    2002-01-01

    In the solids and molecules different types of bonds are presented depending on the involved atoms, covalent bonds are common among elements of open shell, where more bond orbitals are filled than anti bond orbitals. It is expected that ionic bonds among closed shell atoms which have charges of opposite sign. Bonds type Van der Waals are presented among molecules which have a bipolar moment. It would not be expected bonds among zero charge species, or more generally with the same nominal charge and in any case the attractive forces would be very small. In fact it is expected that two metallic cations to be repelled each other. There recently is evidence that in organic or organometallic compounds could exist attractive interactions between two cations of the d 8 -d 10 -s 2 families. These bonds are weak but stronger than those of Van der Waals. They are compared with the hydrogen bonds. In this work it was reviewed some examples in which the goldenphilicity plays an important role in the luminescence that the gold complexes present. Examples of mono, bi and trinuclear and the structures that these organometallic compounds could take are examined. (Author)

  1. 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.

  2. Luminescent properties of Y3Al5−xGaxO12:Ce crystals

    International Nuclear Information System (INIS)

    Zorenko, Yu.; Zorenko, T.; Malinowski, P.; Sidletskiy, O.; Neicheva, S.

    2014-01-01

    Absorption, luminescent and scintillation properties of Ce 3+ doped Y 3 Al 5−x Ga x O 12 crystals with Ga content in the x=1–5 range were investigated in this work and compared with the properties of YAG:Ce crystals. Apart from the traditional spectral methods (absorption, cathodoluminescence and light yield measurements), the intrinsic and Ce 3+ related luminescence of Y 3 Al 5−x Ga x O 12 :Ce solid-solution were also investigated using the luminescent spectroscopy under excitation by synchrotron radiation in the 3.7–25 eV range. We show that the optical properties Y 3 Al 5−x Ga x O 12 :Ce garnets monotonically change with increasing the Ga content in the x=0–3 range due to preferable localization of Ga ions in the tetrahedral position of the garnet lattice. At the highest Ga concentration (x>3) the deviation of the optical properties of Y 3 Al 5−x Ga x O 12 :Ce garnets is observed from the respective properties of these crystals with Ga content in the x=0–3 range due to occupation by Ga ions of the octahedral position in the garnet host. - Highlights: • Different dependence of optical properties of Y 3 Al 5−x Ga x O 12 :Ce crystals on Ga content in x=0–3 and 3–5 ranges. • Elimination of the luminescence of Y Al antisite defects in Y 3 Al 5−x Ga x O 12 :Ce crystals at x>2. • Significant improvement of the scintillation properties of Y 3 Al 5−x Ga x O 12 :Ce crystals at x=2 and 3 in comparison with YAG:Ce

  3. A luminescent Lanthanide-free MOF nanohybrid for highly sensitive ratiometric temperature sensing in physiological range.

    Science.gov (United States)

    Zhou, You; Zhang, Denan; Zeng, Jin; Gan, Ning; Cuan, Jing

    2018-05-01

    Luminescent MOF materials with tunable emissions and energy/charge transfer processes have been extensively explored as ratiometric temperature sensors. However, most of the ratiometric MOF thermometers reported thus far are based on the MOFs containing photoactive lanthanides, which are potentially facing cost issue and serious supply shortage. Here, we present a ratiometric luminescent thermometer based on a dual-emitting lanthanide-free MOF hybrid, which is developed by encapsulation of a fluorescent dye into a robust nanocrystalline zirconium-based MOF through a one-pot synthesis approach. The structure and morphology of the hybrid product was characterized by Powder X-ray diffraction (PXRD), N 2 adsorption-desorption measurement and Scanning electron microscopy (SEM). The pore confinement effect well isolates the guest dye molecules and therefore suppresses the nonradiative energy transfer process between dye molecules. The incorporated dye emission is mainly sensitized by the organic linkers within MOF through fluorescence resonance energy transfer. The ratiometric luminescence of the MOF hybrid shows a significant response to temperature due to the thermal-related back energy transfer process from dye molecules and organic linkers, thus can be exploited for self-calibrated temperature sensing. The maximum thermometric sensitivity is 1.19% °C -1 in the physiological temperature range, which is among the highest for the ratiomtric MOF thermometers that operating in 25-45°C. The temperature resolution is better than 0.1°C over the entire operative range (20-60°C). By integrating the advantages of excellent stability, nanoscale nature, and high sensitivity and precision in the physiological temperature range, this dye@MOF hybrid might have potential application in biomedical diagnosis. What' more, this work has expanded the possibility of non-lanthanide luminescent MOF materials for the development of ratiometric temperature sensors. Copyright © 2018

  4. Organic scintillators with long luminescent lifetimes for radiotherapy dosimetry

    DEFF Research Database (Denmark)

    Beierholm, Anders Ravnsborg; Lindvold, Lars René; Andersen, Claus Erik

    2011-01-01

    of experiments performed using two organic scintillators, one commercially available and one custom made. The luminescent lifetimes of the scintillators have been measured using i) optical excitation by pulsed UV light, and ii) irradiative excitation using high-energy X-rays from a linac. A luminescent lifetime...... component on the order of 20 μs was estimated for the custom-made organic scintillator, while the commercial scintillator exhibited a fast component of approximately 5 ns lifetime (7 ns as stated by the manufacturer) and an approximate 10 μs lifetime slow component. Although these lifetimes are not long...

  5. Concentration depolarization of luminescence of Eu3+-doped glasses

    International Nuclear Information System (INIS)

    Bodunov, E.N.; Lebedev, V.P.; Malyshev, V.A.; Przheuskij, A.K.

    1989-01-01

    Experimental study of concentrational depolarization luminescence (CDL) of phosphate and germanate glasses, containing Eu 3+ ions, has been carried out. On the basis of three-body self-consistent approximation the theory of CDL is conceived, which takes into account Eu-Eu interaction of higher multipolarities. By comparing the theory with the experiment energy transfer radii for Eu-Eu dipole-dipole, dipole-quadrupole and quadrupole-quadrupole interactions are determined. The attempt to discriminate Eu-Eu interaction types in the studied range of Eu 3+ ion concentration change has failed owing to law accuracy of luminescence emittance anisotropy measurement

  6. Anti-Stokes Luminescence in High Quality Quantum Wells

    Science.gov (United States)

    Vinattieri, A.; Bogani, F.; Miotto, A.; Ceccherini, S.

    1997-11-01

    We present a detailed investigation of the anti-Stokes (AS) luminescence which originates from exciton recombination when below gap excitation is used, in a set of high quality quantum well structures. We observe strong excitonic resonances in the AS signal as measured from photoluminescence and photoluminescence excitation spectra. We demonstrate that neither the electromagnetic coupling between the wells nor the morphological disorder can explain this up-conversion effect. Time-resolved luminescence data after ps excitation and fs correlation spectroscopy results provide clear evidence of the occurrence of a two-step absorption which is assisted by the exciton population resonantly excited by the first photon.

  7. Luminescent solar concentrators with fiber geometry.

    Science.gov (United States)

    Edelenbosch, Oreane Y; Fisher, Martyn; Patrignani, Luca; van Sark, Wilfried G J H M; Chatten, Amanda J

    2013-05-06

    The potential of a fibre luminescent solar concentrator has been explored by means of both analytical and ray-tracing techniques. Coated fibres have been found to be more efficient than homogeneously doped fibres, at low absorption. For practical fibres concentration is predicted to be linear with fibre length. A 1 m long, radius 1 mm, fibre LSC doped with Lumogen Red 305 is predicted to concentrate the AM1.5 g spectrum up to 1100 nm at normal incidence by ~35 x. The collection efficiency under diffuse and direct irradiance in London has been analysed showing that, even under clear sky conditions, in winter the diffuse contribution equals the direct.

  8. 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

  9. Synthesis of mixed ligand europium complexes: Verification of predicted luminescence intensification

    International Nuclear Information System (INIS)

    Lima, Nathalia B.D.; Silva, Anderson I.S.; Gonçalves, Simone M.C.; Simas, Alfredo M.

    2016-01-01

    Mixed ligand europium complexes are predicted to be more luminescent than what would be expected from their corresponding repeating ligand compounds according to a conjecture recently advanced by our research group; a conjecture that has already been validated for strongly luminescent europium complexes. In this article, we seek to further verify the validity of this conjecture for complexes which are much more symmetric, and which thus display lower levels of luminescence. Accordingly, we synthesized complexes Eu(DBM) 3 (L) 2 , and all novel mixed ligand combinations Eu(DBM) 3 (L,L') with L and L' equal to DBSO, PTSO, and TPPO. The syntheses were carried out via displacement reactions from the starting complex Eu(DBM) 3 (H 2 O) 2 , passing through the intermediates Eu(DBM) 3 (L) 2 and finally, by displacement of L by L', arriving at Eu(DBM) 3 (L,L'). The ligands L obey the following order of displacement TPPO>PTSO>DBSO>H 2 O, which had been previously described by our group. In the present article, we further show that this displacement order could have been predicted by Sparkle/RM1 thermochemical calculations. Subsequently, we determined the radiative decay rates, A rad , for all six compounds by photophysical measurements. As expected, results show that the measured A rad values for all novel mixed ligand complexes are larger than the average of the A rad values for the corresponding repeating ligand coordination compounds. In conclusion, the present article does broaden the scope of our conjecture, which enunciates that an increase in the diversity of ligands around the europium ion tends to intensify the luminescence. - Highlights: • Mixed ligand europium complexes are predicted to be more luminescent than repeating ligand ones. • Radiative decay rates increase with structural coordination asymmetry. • The non-ionic ligands displacement order in substitution reactions is TPPO>PTSO>DBSO>H 2 O. • Sparkle/RM1 correctly predicts the

  10. 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

  11. 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)

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. Cooled optically stimulated luminescence in CaF2:Mn

    International Nuclear Information System (INIS)

    Miller, S.D.; Endres, G.W.R.; McDonald, J.C.; Swinth, K.L.

    1988-01-01

    A new optically stimulated luminescence technique has been developed for the readout of CaF 2 :Mn thermoluminescent material. Minimum detectable gamma exposures may potentially be measured at 10 nC.kg -1 using the 254 nm line of a mercury lamp. Additional studies were done on CaF 2 :Mn using 351 nm excimer laser stimulation. (author)

  17. 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

  18. Time-resolved luminescence from feldspars: New insight into fading

    DEFF Research Database (Denmark)

    Tsukamoto, S.; Denby, P.M.; Murray, A.S.

    2006-01-01

    Time-resolved infrared optically stimulated luminescence (IR-OSL) signals of K- and Na-feldspar samples extracted from sediments were measured in UV, blue and red detection windows, using a fast photon counter and pulsed IR stimulation (lambda = 875 nm). We observe that the relative contribution ...

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. A portable luminescence dating instrument

    DEFF Research Database (Denmark)

    Kook, M.H.; Murray, A.S.; Lapp, Torben

    2011-01-01

    We describe a portable luminescence reader suitable for use in remote localities in the field. The instrument weighs about 8kg and is based around a 30mm bialkali photomultiplier detecting signals through a glass filter centered on 340nm. Stimulation is by 470nm blue LEDs (24W in total) operating...

  6. The effects of Tb 3+ doping concentration on luminescence ...

    Indian Academy of Sciences (India)

    BaF2 phosphor; crystal structure; luminescence properties; X-ray diffraction; concentration quenching. 1. Introduction ... reported that the particle size, shape, crystallinity, etc., sig- nificantly ... Figure 3 shows the excitation and emission spectra of sam- ple with 4 ... gies obtained earlier.9,10 The ground term of the Tb3+ ion is.

  7. Luminescence of nanocrystalline ZnSe:Mn2+

    NARCIS (Netherlands)

    Suyver, J.F.; Wuister, S.F.; Kelly, J.J.; Meijerink, A.

    2000-01-01

    The luminescence properties of nanocrystalline ZnSe:Mn^(2+) prepared via an inorganic chemical synthesis are described. Photoluminescence spectra show distinct ZnSe and Mn^(2+) related emissions, both of which are excited via the ZnSe host lattice. The Mn^(2+) emission wavelength and the

  8. Synthesis and luminescence in sol–gel auto-combustion ...

    Indian Academy of Sciences (India)

    2017-11-14

    Nov 14, 2017 ... Eu-doped CaSnO3 showed broad blue emission centred about 434 nm, a ... symmetry [5]. Recently, luminescence properties of rare-earth-cation- ... able attention due to their abundant emission colours based on their 4f–4f or ...

  9. Characterization of Nanostructured Semiconductors by Ultrafast Luminescence Imaging

    Science.gov (United States)

    Blake, Jolie

    -diffusion controlled recombination. In the second phase of this study the setup was configured to the ultraviolet detection range for measuring the nanowires of conductive metal oxides. ZnO was the metal oxide of focus in this research. Ultrafast measurements were conducted on ZnO nanowires and ASE dynamics from multiple regions along a nanowire were again fitted to the ASE model and the recombination constants extracted. The diminished influence of the Shockley-Read-Hall recombination rate on the measured luminescence suggested that leading quadratic term in the model is a measure of a two-body defect mediated recombination rate, from which a defect density could be calculated. The measured change in defect density along the length of the nanowire correlated with changes in the growth conditions that established a defect gradient. The results show that the Kerr-gated system, as well as being a probe of ultrafast dynamics, is also a new tool for measuring changes in defect density in single nanostructures.

  10. 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

    easily accessible for water and thus show shorter luminescence decay times and a more symmetrical coordination sphere, which is mostly made up by water molecules. Another investigated aspect was the influence of surface modifications on the luminescence behavior of the lanthanide ions inside the material. Here we could show, that surface modifications hydrophobize the material and thus are able to protect the lanthanide ions from water, which is important for the conservation of the luminescence properties. Concerning the mesoporous silicates, again a heterogeneous distribution of the lanthanide ions in the pore system was found. A part of the lanthanide ions interacts with the pore wall, while the other part is located in the aqueous phase inside the pores. Surface modification led to a interaction of the lanthanide ions with the modification. This was reflected in the luminescence properties depending on the structure of the modification and the surface loading.

  11. Luminescence properties of common salt (NaCl available in Nigeria for use as accident dosimeter in radiological emergency situation

    Directory of Open Access Journals (Sweden)

    Janet Ayobami Ademola

    2017-04-01

    Full Text Available In the event of a radiological accident or attack, it is important to assess and quantify radiation dose to the population. This could be done using materials in the vicinity that are sensitive to ionizing radiation. Common salt (NaCl is known to be a sensitive thermoluminescence (TL phosphor. Luminescence properties of common salt (NaCl used in Nigeria were investigated using an automated luminescence reader Risø TL/OSL-DA-15, with attention focused more on the Optically Stimulated Luminescence (OSL. Strong radiation-induced TL and OSL signals were observed. The TL peaks occurred at about 100 °C, 240 °C and 280 °C. The dose response of both the TL and OSL signals showed a linear relationship. From the OSL pulse anneal curve with TL curve, a preheat temperature of 190 °C for 10 s was found adequate for the OSL measurements. There was no significant difference in the OSL decay for stimulation temperatures of 100 and 120 °C. Fading experiment over a storage period of 14 days showed about 13 and 3% decrease in the OSL signal of sample 1 and sample 2, respectively. The ratios of measured to given dose for dose recovery test were within ±19% of unity. Within the limit of error the samples could be used as a complementary emergency dosimeter in radiological accident situation.

  12. 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

  13. Luminescence and Luminescence Quenching of K2Bi(PO4)(MoO4):Eu3+ Phosphors with Efficiencies Close to Unity.

    Science.gov (United States)

    Grigorjevaite, Julija; Katelnikovas, Arturas

    2016-11-23

    A very good light emitting diode (LED) phosphor must have strong absorption, high quantum efficiency, high color purity, and high quenching temperature. Our synthesized K 2 Bi(PO 4 )(MoO 4 ):Eu 3+ phosphors possess all of the mentioned properties. The excitation of these phosphors with the near-UV or blue radiation results in a bright red luminescence dominated by the 5 D 0 → 7 F 2 transition at ∼615 nm. Color coordinates are very stable when changing Eu 3+ concentration or temperature in the range of 77-500 K. Furthermore, samples doped with 50% and 75% Eu 3+ showed quantum efficiencies close to 100% which is a huge benefit for practical application. Temperature dependent luminescence measurements showed that phosphor performance increases with increasing Eu 3+ concentration. K 2 Eu(PO 4 )(MoO 4 ) sample at 400 K lost only 20% of the initial intensity at 77 K and would lose half of the intensity only at 578 K. Besides, the ceramic disks with thicknesses of 0.33 and 0.89 mm were prepared from K 2 Eu(PO 4 )(MoO 4 ) powder, and it turned out that they efficiently converted the radiation of 375 nm LED to the red light. The conversion of 400 nm LED radiation to the red light was not complete; thus, the light sources with various tints of purple color were obtained. The combination of ceramic disks with 455 nm LED yielded the light sources with tints of blue color due to the low absorption of ceramic disk in this spectral range. In addition, these phosphors possess a very unique emission spectra; thus, they could also be applied in luminescent security pigments.

  14. 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.

  15. Analysis of structure origin and luminescence properties of Yb(3+)-Er(3+) co-doped fluorophosphate glass.

    Science.gov (United States)

    Chen, Fangze; Jing, Xufeng; Wei, Tao; Wang, Fengchao; Tian, Ying; Xu, Shiqing

    2014-08-14

    The near infrared luminescence properties of Yb(3+)-Er(3+) co-doped fluorophosphate glasses have been investigated. The various effects on structure and 1.53 μm emission were analyzed as a function of Yb(3+) concentration. The energy transfer mechanism was proposed. High measured lifetime (10.75 ms), large effective full widths at half maximum (73.71 nm) and large gain per unit length (62.8 × 10(-)(24)cm(2)s) have been achieved in prepared glass. The present glass co-doped with 6mol% YbF3 and 2 mol% ErF3 showed magnificent luminescence properties for telecommunication application. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Convenient determination of luminescence quantum yield using a combined electronic absorption and emission spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, John; Mishra, Ashok Kumar [Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036 (India)

    2016-01-15

    It is possible to measure luminescence quantum yield in a facile way, by designing an optical spectrometer capable of obtaining electronic absorption as well as luminescence spectra, with a setup that uses the same light source and detector for both the spectral measurements. Employment of a single light source and single detector enables use of the same correction factor profile for spectral corrections. A suitable instrumental scaling factor is used for adjusting spectral losses.

  17. Reproducibility of optically stimulated luminescence measurements from single grains of Al2O3: C and annealed quartz

    DEFF Research Database (Denmark)

    Truscott, A.J.; Duller, G.A.T.; Bøtter-Jensen, L.

    2000-01-01

    of nine-by-nine holes, which are drilled in the sample disc, We report on tests carried out to determine the precision with which the laser beam can be directed at individual grains in these holes. Single grains of aluminium oxide (Al2O3:C) (90-180 mum) and annealed quartz (90-120 mum) were used to test...... the reproducibility with which the OSL signal can be measured. These experiments suggest that the laser beam can be positioned to within 30 mum and that the reproducibility of OSL measurement is 3.5% on an average. (C) 2000 Elsevier Science Ltd. All rights reserved....

  18. 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.

  19. 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.

  20. 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

  1. Nervous control of photophores in luminescent fishes.

    Science.gov (United States)

    Zaccone, Giacomo; Abelli, Luigi; Salpietro, Lorenza; Zaccone, Daniele; Macrì, Battesimo; Marino, Fabio

    2011-07-01

    Functional studies of the autonomic innervation in the photophores of luminescent fishes are scarce. The majority of studies have involved either the stimulation of isolated photophores or the modulatory effects of adrenaline-induced light emission. The fish skin is a highly complex organ that performs a wide variety of physiological processes and receives extensive nervous innervations. The latter includes autonomic nerve fibers of spinal sympathetic origin having a secretomotor function. More recent evidence indicates that neuropeptide-containing nerve fibers, such as those that express tachykinin and its NK1 receptor, neuropeptide Y, or nitric oxide, may also play an important role in the nervous control of photophores. There is no anatomical evidence that shows that nNOS positive (nitrergic) neurons form a population distinct from the secretomotor neurons with perikarya in the sympathetic ganglia. The distribution and function of the nitrergic nerves in the luminous cells, however, is less clear. It is likely that the chemical properties of the sympathetic postganglionic neurons in the ganglia of luminescent fishes are target-specific, such as observed in mammals. Copyright © 2010 Elsevier GmbH. All rights reserved.

  2. Temperature dependence of luminescence from silica glasses under in-reactor and 60Co gamma-ray irradiation

    Science.gov (United States)

    Takahara, Shogo; Yoshida, Tomoko; Tanabe, Tetuo; , Tatuya, Ii; Hirano, Masahiro; Okada, Moritami

    2004-06-01

    In order to investigate the temperature effects on the dynamic radiation damaging process, we have carried out in situ measurements of in-reactor luminescence (IRL) and gamma-ray induced luminescence (GIL) of a silica glass at temperatures ranging from 70 K to 370 K. Both luminescence spectra were found to consist of two broad emission centers at 3.1 eV and 4.1 eV with an additional temperature independent emission around 2.5 eV. The 2.5 eV emission different from the other two showed long tail to the lower energy side and was attributed to the Cherenkov radiation. The 3.1 eV band was attributed to a B 2 β oxygen deficient center on the basis of our photoluminescence measurement. The intensity of the 3.1 eV IRL increased with increasing temperature up to ca. 200 K and saturated above 200 K, which is clearly different from the reported temperature dependence of 3.1 eV photoluminescence, suggesting the existence of some different relaxation mechanism of excited electron under ionizing radiations.

  3. Luminescence and scintillation enhancement of Y2O3:Tm transparent ceramic through post-fabrication thermal processing

    International Nuclear Information System (INIS)

    Chapman, M.G.; Marchewka, M.R.; Roberts, S.A.; Schmitt, J.M.; McMillen, C.; Kucera, C.J.; DeVol, T.A.; Ballato, J.; Jacobsohn, L.G.

    2015-01-01

    The effects of post-fabrication thermal processing in O 2 flux on the luminescence and scintillation of a Y 2 O 3 :Tm transparent ceramic were investigated. The results showed that the strategy of post-fabrication processing can be beneficial to the performance of the ceramics, depending on the cumulative processing time. After the first hour of processing, about 40% enhancement in the luminescence output together with about 20% enhancement in the scintillation light yield were obtained. The enhancements were tentatively assigned to the incorporation of oxygen into vacancy sites. Longer cumulative processing times lead to the incorporation of oxygen as interstitials that is detrimental to scintillation light yield but not to luminescence output. This work also revealed that thermoluminescence measurements are a useful tool to predict scintillation light yield of Y 2 O 3 :Tm. - Highlights: • Scintillation and PL enhancement of transparent ceramics through thermal processing. • First thermoluminescence measurements of Y 2 O 3 :Tm above room temperature. • Observation of correlation between TL and scintillation light yield results

  4. Luminescence properties of lustre decorated majolica

    Science.gov (United States)

    Galli, A.; Martini, M.; Sibilia, E.; Padeletti, G.; Fermo, P.

    Luminescence measurements have been performed on several Italian Renaissance ceramic shards produced in central Italy, as well as on some others from Hispano-Moresque and Fatimid periods. The aim of this study was the characterisation of the raw materials used to manufacture lustre decorated majolica. At first, the thermoluminescence (TL) dating of all ceramic bodies was performed, because the shards lacked sure chronological attribution, having been provided by private collectors, or found during emergency restoration works or archaeological surveys. To characterise the defects and the recombination centers of the different components of the ceramics (ceramic body, glaze, glaze, and lustre), radioluminescence (RL) measurements have been performed on samples representative of each historical period. The dating results are reported, as well as the preliminary RL results.

  5. Luminescence of LiH(D):Ru monocrystals

    International Nuclear Information System (INIS)

    Sabirzyanov, A.A.; Oparin, D.V.; Pilipenko, G.I.; Gavrilov, F.F.

    1993-01-01

    Luminescence of lithium hydride (deuteride) activated by ruthenium is recorded for the first time. The features connected with the structure and oscillations of the basic lattice are detected in luminescence spectrum. The qualitative model of luminescence spectrum is suggested

  6. Cerenkov luminescence imaging of medical isotopes.

    Science.gov (United States)

    Ruggiero, Alessandro; Holland, Jason P; Lewis, Jason S; Grimm, Jan

    2010-07-01

    The development of novel multimodality imaging agents and techniques represents the current frontier of research in the field of medical imaging science. However, the combination of nuclear tomography with optical techniques has yet to be established. Here, we report the use of the inherent optical emissions from the decay of radiopharmaceuticals for Cerenkov luminescence imaging (CLI) of tumors in vivo and correlate the results with those obtained from concordant immuno-PET studies. In vitro phantom studies were used to validate the visible light emission observed from a range of radionuclides including the positron emitters (18)F, (64)Cu, (89)Zr, and (124)I; beta-emitter (131)I; and alpha-particle emitter (225)Ac for potential use in CLI. The novel radiolabeled monoclonal antibody (89)Zr-desferrioxamine B [DFO]-J591 for immuno-PET of prostate-specific membrane antigen (PSMA) expression was used to coregister and correlate the CLI signal observed with the immuno-PET images and biodistribution studies. Phantom studies confirmed that Cerenkov radiation can be observed from a range of positron-, beta-, and alpha-emitting radionuclides using standard optical imaging devices. The change in light emission intensity versus time was concordant with radionuclide decay and was also found to correlate linearly with both the activity concentration and the measured PET signal (percentage injected dose per gram). In vivo studies conducted in male severe combined immune deficient mice bearing PSMA-positive, subcutaneous LNCaP tumors demonstrated that tumor-specific uptake of (89)Zr-DFO-J591 could be visualized by both immuno-PET and CLI. Optical and immuno-PET signal intensities were found to increase over time from 24 to 96 h, and biodistribution studies were found to correlate well with both imaging modalities. These studies represent the first, to our knowledge, quantitative assessment of CLI for measuring radiotracer uptake in vivo. Many radionuclides common to both nuclear

  7. 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

  8. Magnetic and luminescent hybrid nanomaterial based on Fe{sub 3}O{sub 4} nanocrystals and GdPO{sub 4}:Eu{sup 3+} nanoneedles

    Energy Technology Data Exchange (ETDEWEB)

    Runowski, Marcin; Grzyb, Tomasz; Lis, Stefan, E-mail: blis@amu.edu.pl [Adam Mickiewicz University, Department of Rare Earths, Faculty of Chemistry (Poland)

    2012-10-15

    A bifunctional hybrid nanomaterial, which can show magnetic and luminescent properties, was obtained. A magnetic phase was synthesized as a core/shell type composite. Nanocrystalline magnetite, Fe{sub 3}O{sub 4} was used as the core and was encapsulated in a silica shell. The luminescent phase was GdPO{sub 4} doped with Eu{sup 3+} ions, as the emitter. The investigated materials were synthesized using a coprecipitation method. Encapsulated Fe{sub 3}O{sub 4} was 'trapped' in a nano-scaffold composed of GdPO{sub 4} crystalline nanoneedles. When an external magnetic field was applied, this hybrid composite was attracted in one direction. Also, the luminescent phase can move simultaneously with magnetite due to a 'trapping' effect. The structure and morphology of the obtained nanocomposites were examined with the use of transmission electron microscopy and X-ray powder diffraction. Spectroscopic properties of the Eu{sup 3+}-doped nanomaterials were studied by measuring their excitation and emission spectra as well as their luminescence decay times.Graphical Abstract.

  9. Concentration characteristics and cell arrangement in luminescent concentrator PV modules; Keiko shukogata taiyo denchi module no cell haichi to shuko tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Inamura, A [Science University of Tokyo, Tokyo (Japan); Sakuta, K [Electrotechnical Laboratory, Tsukuba (Japan)

    1997-11-25

    A luminescent concentrator PV module requires no tracking equipment and can use scattered light. A mini PV module was prepared from a luminescent plate of 100times100times3mm, and a single-crystalline PV cell of 100times20mm. Characteristics of various prototype modules with different PV cell areas and cell arrangements were also measured. Four kinds of edge reflecting materials with different reflectances by various white coating were applied to Al sashes for module frames, and each sash was fixed on one edge of the luminescent plate. In experiment, 3 other edges were covered with black tapes to reduce each reflectance to 0%. Although PV module output was affected by reflectance of edges, the output was satisfactory at 90% or more in reflectance showing no difference in output. A concentrating efficiency decreased with an increase in luminescent plate (concentrator) area, while it was improved by cell arrangement with short optical pass length, and cell arrangement hardly affected by edge reflection. 4 refs., 7 figs.

  10. Luminescence and energy transfer of Tb3+-doped BaO-Gd2O3-Al2O3-B2O3-SiO2 glasses.

    Science.gov (United States)

    Zuo, Chenggang; Huang, Jinze; Liu, Shaoyou; Xiao, Anguo; Shen, Youming; Zhang, Xiangyang; Zhou, Zhihua; Zhu, Ligang

    2017-12-05

    Transparent Tb 3+ -doped BaO-Gd 2 O 3 -Al 2 O 3 -B 2 O 3 -SiO 2 glasses with the greater than 4g/cm 3 were prepared by high temperature melting method and its luminescent properties have been investigated by measured UV-vis transmission, excitation, emission and luminescence decay spectra. The transmission spectrum shows there are three weak absorption bands locate at about 312, 378 and 484nm in the glasses and it has good transmittance in the visible spectrum region. Intense green emission can be observed under UV excitation. The effective energy transfer from Gd 3+ ion to Tb 3+ ion could occur and sensitize the luminescence of Tb 3+ ion. The green emission intensity of Tb 3+ ion could change with the increasing SiO 2 /B 2 O 3 ratio in the borosilicate glass matrix. With the increasing concentration of Tb 3+ ion, 5 D 4 → 7 F J transitions could be enhanced through the cross relaxation between the two nearby Tb 3+ ions. Luminescence decay time of 2.12ms from 546nm emission is obtained. The results indicate that Tb 3+ -doped BaO-Gd 2 O 3 -Al 2 O 3 -B 2 O 3 -SiO 2 glasses would be potential scintillating material for applications in X-ray imaging. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Luminescent zinc(ii) and copper(i) complexes for high-performance solution-processed monochromic and white organic light-emitting devices.

    Science.gov (United States)

    Cheng, Gang; So, Gary Kwok-Ming; To, Wai-Pong; Chen, Yong; Kwok, Chi-Chung; Ma, Chensheng; Guan, Xiangguo; Chang, Xiaoyong; Kwok, Wai-Ming; Che, Chi-Ming

    2015-08-01

    The synthesis and spectroscopic properties of luminescent tetranuclear zinc(ii) complexes of substituted 7-azaindoles and a series of luminescent copper(i) complexes containing 7,8-bis(diphenylphosphino)-7,8-dicarba- nido -undecaborate ligand are described. These complexes are stable towards air and moisture. Thin film samples of the luminescent copper(i) complexes in 2,6-dicarbazolo-1,5-pyridine and zinc(ii) complexes in poly(methyl methacrylate) showed emission quantum yields of up to 0.60 (for Cu-3 ) and 0.96 (for Zn-1 ), respectively. Their photophysical properties were examined by ultrafast time-resolved emission spectroscopy, temperature dependent emission lifetime measurements and density functional theory calculations. Monochromic blue and orange solution-processed OLEDs with these Zn(ii) and Cu(i) complexes as light-emitting dopants have been fabricated, respectively. Maximum external quantum efficiency (EQE) of 5.55% and Commission Internationale de l'Eclairage (CIE) coordinates of (0.16, 0.19) were accomplished with the optimized Zn-1 -OLED while these values were, respectively 15.64% and (0.48, 0.51) for the optimized Cu-3 -OLED. Solution-processed white OLEDs having maximum EQE of 6.88%, CIE coordinates of (0.42, 0.44), and colour rendering index of 81 were fabricated by using these luminescent Zn(ii) and Cu(i) complexes as blue and orange light-emitting dopant materials, respectively.

  12. Electron paramagnetic resonance studies of a new luminescent material based on CaB{sub 6}O{sub 10}:Pb

    Energy Technology Data Exchange (ETDEWEB)

    Franca, L. V. S.; Oliveira, L. C.; Baffa, O., E-mail: leofranca@usp.br [Universidade de Sao Paulo, FFCLRP, Departamento de Fisica, Av. Bandeirantes 3900, CEP 14040-901, Bairro Monte Alegre, Ribeirao Preto, Sao Paulo (Brazil)

    2017-10-15

    A new photostimulable phosphor based on Pb-doped CaB{sub 6}O{sub 10} was recently synthesized and its luminescence properties studied. This material is very promising exhibiting high sensitivity to ionizing radiation, comparable or surpassing commercially available luminescence materials such LiF:Mg,Ti and Al{sub 2}O{sub 3}:C with a dominant thermoluminescence (Tl) peak at ∼180 degrees Celsius and an optically stimulated luminescence (OSL) signal that can be ∼99% read within ∼ 20s under current experimental conditions. The radioluminescence, Tl and OSL signals are dominated by an emission band at ∼320 nm, probably associated with {sup 3}P{sub 1} → {sup 1}S{sub 0} transition of Pb{sup 2+}. However, the involvement of the Pb dopant in the trapping process is not completely clear and Electron Paramagnetic Resonance (EPR) spectroscopy is being used to study the valence states of the Pb ion before and after irradiation. EPR measurements were carried out using a Jeol FX200 X-band spectrometer at liquid nitrogen temperature. The material was irradiated with a dose of 500 Gy using a 160 kV X-ray tube. The EPR spectrum shows the appearance of a symmetrical central line at g ∼ 2.0 and a line at high field at g ∼ 1.2 with orthorhombic symmetry. This study is under way with more experiments to correlate these findings with the luminescence properties. (Author)

  13. 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)

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. Handbook of luminescent semiconductor materials

    CERN Document Server

    Bergman, Leah

    2011-01-01

    Photoluminescence spectroscopy is an important approach for examining the optical interactions in semiconductors and optical devices with the goal of gaining insight into material properties. With contributions from researchers at the forefront of this field, Handbook of Luminescent Semiconductor Materials explores the use of this technique to study semiconductor materials in a variety of applications, including solid-state lighting, solar energy conversion, optical devices, and biological imaging. After introducing basic semiconductor theory and photoluminescence principles, the book focuses

  19. Electrostatic probes in luminescent discharges

    International Nuclear Information System (INIS)

    Cunha Raposo, C. da.

    1980-01-01

    A system to produce luminescent type plasma by continuos discharge and ionization by high frequency was constructed. The ionization was done in the air and in the argon under pressures from 3 to 10 mmHg. The parameters of a non magnetized collisional plasma and the parameters of a magnetized plasma such as, density, eletron temperature and potential, using a Langmuir probe with plane geometry, were determined. (M.C.K.) [pt

  20. Luminescence studies on phosphor screens

    International Nuclear Information System (INIS)

    Panayiotakis, G.; Nomikos, C.; Bakas, A.; Proimos, B.

    1994-01-01

    We report our results on x-ray phosphor screens prepared of some new materials focusing attention on their efficiency under fluoroscopy conditions, on optimization conditions and on comparisons among the various materials. All data are presented in absolute values. A theoretical model is presented, that takes into account the granular structure of the screens, permitting the explanation and prediction of the luminescence properties of the screens. (authors)

  1. Luminescence studies on phosphor screens

    Energy Technology Data Exchange (ETDEWEB)

    Panayiotakis, G; Nomikos, C; Bakas, A; Proimos, B [Medical Physics Department, University of Patras, 265 00 Patras, Greece (Greece)

    1994-12-31

    We report our results on x-ray phosphor screens prepared of some new materials focusing attention on their efficiency under fluoroscopy conditions, on optimization conditions and on comparisons among the various materials. All data are presented in absolute values. A theoretical model is presented, that takes into account the granular structure of the screens, permitting the explanation and prediction of the luminescence properties of the screens. (authors). 12 refs, 3 figs.

  2. 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

  3. 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.

  4. Characterization of UV written waveguides with luminescence microscopy

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Harpøth, Anders; Rosbirk, Tue

    2005-01-01

    Luminescence microscopy is used to measure the refractive index profile and molecular defect distribution of UV written waveguides with a spatial resolution of ~0.4 mm and high signal-to-noise ratio. The measurements reveal comlex waveguide formation dynamics with significant topological changes...... in the core profile. In addition, it is observed that thewaveguide formation process requires several milliseconds of UV exposure before starting....

  5. Systematic development of new thermoluminescence and optically stimulated luminescence materials

    Energy Technology Data Exchange (ETDEWEB)

    Yukihara, E.G., E-mail: eduardo.yukihara@okstate.edu [Physics Department, 145 Physical Sciences II, Oklahoma State University, Stillwater, OK 74078 (United States); Milliken, E.D.; Oliveira, L.C. [Physics Department, 145 Physical Sciences II, Oklahoma State University, Stillwater, OK 74078 (United States); Orante-Barron, V.R. [Departamento de Investigacion en Polimeros y Materiales, Universidad de Sonora, Hermosillo, Sonora 83000, Mexico (Mexico); Jacobsohn, L.G. [Center for Optical Materials Science and Engineering Technologies (COMSET), and School of Materials Science and Engineering, Clemson University, Clemson, SC (United States); Blair, M.W. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2013-01-15

    This paper presents an overview of a systematic study to develop new thermoluminescence (TL) and optically stimulated luminescence (OSL) materials using solution combustion synthesis (SCS) for applications such as personal OSL dosimetry, 2D dose mapping, and temperature sensing. A discussion on the material requirements for these applications is included. We present X-ray diffraction (XRD) data on single phase materials obtained with SCS, as well as radioluminescence (RL), TL and OSL data of lanthanide-doped materials. The results demonstrate the possibility of producing TL and OSL materials with sensitivity similar to or approaching those of commercial TL and OSL materials used in dosimetry (e.g., LiF:Mg,Ti and Al{sub 2}O{sub 3}:C) using SCS. The results also show that the luminescence properties can be improved by Li co-doping and annealing. The presence of an atypical TL background and anomalous fading are discussed and deserve attention in future investigations. We hope that these preliminary results on the use of SCS for production of TL and OSL materials are helpful to guide future efforts towards the development of new luminescence materials for different applications. - Highlights: Black-Right-Pointing-Pointer TL and OSL material produced with sensitivity similar to commercial materials. Black-Right-Pointing-Pointer Luminescence properties improved by Li co-doping and annealing. Black-Right-Pointing-Pointer The presence of atypical TL background and anomalous fading observed.

  6. Toxicity Evaluation of Pig Slurry Using Luminescent Bacteria and Zebrafish

    Directory of Open Access Journals (Sweden)

    Wenyan Chen

    2014-07-01

    Full Text Available Biogas slurry has become a serious pollution problem and anaerobic digestion is widely applied to pig manure treatment for environmental protection and energy recovery. To evaluate environmental risk of the emission of biogas slurry, luminescent bacteria (Vibrio fischeri, larvae and embryos of zebrafish (Danio rerio were used to detect the acute and development toxicity of digested and post-treated slurry. Then the ability of treatment process was evaluated. The results showed that digested slurry displayed strong toxicity to both zebrafish and luminescent bacteria, while the EC50 for luminescent bacteria and the LC50 for larvae were only 6.81% (v/v and 1.95% (v/v respectively, and embryonic development was inhibited at just 1% (v/v. Slurry still maintained a high level of toxicity although it had been treated by membrane bioreactor (MBR, while the LC50 of larvae was 75.23% (v/v and there was a little effect on the development of embryos and V. fischeri; the results also revealed that the zebrafish larvae are more sensitive than embryos and luminescent bacteria to pig slurry. Finally, we also found the toxicity removal rate was higher than 90% after the treatment of MBR according to toxicity tests. In conclusion, further treatment should be used in pig slurry disposal or reused of final effluent.

  7. Application of Quantum Dot nanocrystal in Luminescent solar concentrators

    Science.gov (United States)

    Bakhoda, Shokoufeh; Khalaji Assadi, Morteza; Ahmadi Kandjani, Sohrab; Kayiem, Hussain H. Al; Hussain Bhat, Aamir

    2018-03-01

    The basic design of luminescent solar concentrator is a transparent plate doped with an appropriate luminescent material (organic dyes, quantum dots), which is able to absorb sunlight (direct and diffuse), and then guides photons produced by photoluminescence to its narrow edges where they are converted by photovoltaic cells. Unfortunately, LSCs have suffered from numerous efficiency losses. Therefore, new luminescent species and novel approaches are needed for its practical application. This paper deals with investigation of nonhazardous, environmental friendly luminescent species include CuInS2/ZnS core/shell QDs. The CuInS2/ZnS QDs possess advantages of Stocks shift as large as more than 130 nm and high photoluminescence quantum yield of 80%. The paper presents the effect of large stock shift CuInS2/ZnS QDs on reducing the reabsorption losses in LSC by using experimental investigation. The LSC sheets were fabricated by dispersing CuInS2/ZnS QDs particles in a polymethylmethacrylate waveguide. A series of LSCs (dimension 4.0 cm × 3.0 cm × 0.3cm) with different CuInS2/ZnS QDs particles concentration (0.015 and 0.03 wt.%) were fabricated and their optical properties (absorptions/emissions) were characterized. The results show that the CuInS2/ZnS QDs-LSC provides a promising way for the reduction of reabsorption losses in LSCs.

  8. 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.

  9. 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

  10. Yellow stimulated luminescence from potassium feldspar: Observations on its suitability for dating

    International Nuclear Information System (INIS)

    Lauer, T.; Krbetschek, M.; Mauz, B.; Frechen, M.

    2012-01-01

    Yellow stimulated luminescence (Y-OSL) is the light detected from potassium-rich feldspars at 410 nm under stimulation by a yellow light source emitting 590 nm. The investigation of this study aimed at understanding basic luminescence physics of Y-OSL in order to assess the suitability of the technique for dating. The Y-OSL signal properties tested were signal intensity, thermal assistance, thermal stability, sensitivity to daylight and the suitability of a single aliquot regenerative (SAR) protocol to be employed for equivalent dose (D e ) estimation. D e measurements were conducted on samples of Holocene, last glacial and Tertiary age. The tests were undertaken on sedimentary feldspar separates extracted from aeolian, fluvial and coastal deposits. Results from experiments show that the signal intensity increases by measuring Y-OSL at elevated temperature suggesting thermal assistance characteristics similar to infrared stimulated luminescence (IRSL). The yellow stimulated signal remains unaffected by preheat temperatures up to ∼200 °C suggesting higher thermal stability than the IRSL signal. The Y-OSL signal is less light sensitive than the IRSL signal and D e residuals obtained from modern samples are up to 7 Gy indicating suitability of the technique for ‘older’ and well-bleached sediments. The dose recovery tests successfully recovered the given dose if the specific light sensitivity of Y-OSL is taken into account. For every sample Y-OSL D e values obtained by a single aliquot regenerative dose protocol (SAR) are higher than those obtained by an IRSL SAR approach. From these results we infer high thermal stability and a minimal anomalous fading of the Y-OSL signal. We conclude that Y-OSL has a high potential to date Quaternary sediments that were sufficiently bleached in nature.

  11. 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.

  12. New strategies invonving upconverting nanoparticles for determining moderate temperatures by luminescence thermometry

    Energy Technology Data Exchange (ETDEWEB)

    Savchuk, Ol.A. [Física i Cristallografia de Materials i Nanomaterials (FiCMA-FiCNA) and EMaS, Universitat Rovira i Virgili (URV), c/Marcellí Domingo s/n E-43007, Tarragona (Spain); Carvajal, J.J., E-mail: joanjosep.carvajal@urv.cat [Física i Cristallografia de Materials i Nanomaterials (FiCMA-FiCNA) and EMaS, Universitat Rovira i Virgili (URV), c/Marcellí Domingo s/n E-43007, Tarragona (Spain); Pujol, M.C.; Massons, J. [Física i Cristallografia de Materials i Nanomaterials (FiCMA-FiCNA) and EMaS, Universitat Rovira i Virgili (URV), c/Marcellí Domingo s/n E-43007, Tarragona (Spain); Haro-González, P. [Fluorescence Imaging Group, Departamento de Física de Materiales, Facultad de Ciencias, Universidad Autónoma de Madrid, C/Francisco Tomás y Valiente 7, E-28049 Madrid (Spain); Martínez, O.; Jiménez, J. [GdS-Optronlab, Departamento Física Materia Condensada, Universidad de Valladolid, Edificio I+D, Paseo de Belén 11, 47011 Valladolid (Spain); Aguiló, M.; Díaz, F. [Física i Cristallografia de Materials i Nanomaterials (FiCMA-FiCNA) and EMaS, Universitat Rovira i Virgili (URV), c/Marcellí Domingo s/n E-43007, Tarragona (Spain)

    2016-01-15

    Here we analyze alternative luminescence thermometry techniques to FIR, such as intensity ratio luminescence thermometry between the emission arising from two electronic levels that are not necessarily thermally coupled, but that show different evolutions with temperature, and lifetime luminescence nanothermometry in (Ho,Tm,Yb):KLu(WO{sub 4}){sub 2} and (Er,Yb):NaY{sub 2}F{sub 5}O nanoparticles. (Ho,Tm,Yb):KLu(WO{sub 4}){sub 2} nanoparticles exhibited a maximum relative sensitivity of 0.61% K{sup −1}, similar to that achievable in Er-doped systems, which are the upconverting systems presenting the highest sensitivity. From another side, (Er,Yb):NaY{sub 2}F{sub 5}O nanocrystals show great potentiality as thermal sensors at the nanoscale for moderate temperatures due to the incorporation of additional non-radiative relaxation mechanisms that shorten the emission lifetime generated by the oxygen present in the structure when compared to (Er,Yb):NaYF{sub 4} nanoparticles exhibiting the highest upconversion efficiency. We used those nanoparticles for ex-vivo temperature determination by laser induced heating in chicken breast using lifetime-based thermometry. The results obtained indicate that these techniques might constitute alternatives to FIR with potential applications for the determination of moderate temperatures, with sensitivities comparable to those that can be achieved by FIR or even higher. - Highlights: • Other nanothermometry techniques than FIR proposed with upconversion nanoparticles. • Energy transfer between different lanthanide ions can be used for thermometry. • Lifetime measurements can constitute also a tool for temperature determination.

  13. Identification of irradiated food additives by photostimulated luminescence (PSL) method

    International Nuclear Information System (INIS)

    Yun, Hye Jeong; Kwon, Joong Ho; KIm, Dong Ho; Hur, Jung Mu; Yang, Suh Yung; Lee, Byoung Hun

    2008-01-01

    Photostimulated luminescence (PSL), electron spin resonance (ESR) and thermoluminescence (TL) analyses were conducted to detect whether 258 kinds of extracted and powdered forms food additives were irradiated or not. In a view of the PSL results, 9 kinds of the extracted and powdered samples (3.2%) showed over 5,000 photon counts (60 sec) -1 and these samples were judged to be irradiation-positive. Thirty nine kinds of the samples (15.6%) yielded 700-5,000 photon counts (60 sec) -1 and these samples were grouped into irradiation-potential, while the samples showed below 700 photon counts (60 sec) -1 sec were judged to be irradiation-negative. TL glow curves for minerals separated from 5 samples were detected at 150 degrees C with high intensity. However, TL analysis did not apply to other irradiation-positive and irradiation-potential samples because the minerals for TL detection were not separated from the samples. ESR measurements for irradiation-positive and irradiation-potential samples, judged by PSL detection, showed no specific signals to irradiation. The results indicated that PSL could be applied to identify irradiation treatment of extracted and powdered food additives, while TL was optional and ESR was not suitable for detection extracted and powdered food additives

  14. Luminescence of Er3+ doped double lead halide crystals under X-ray, UV, VIS and IR excitation

    Science.gov (United States)

    Serazetdinov, A. R.; Smirnov, A. A.; Pustovarov, V. A.; Isaenko, L. I.

    2017-09-01

    Er3+ doped double lead halide crystals incorporate a number of properties making them interesting for practical use in light conducting materials. X-ray excited luminescence (XRL) spectra, photoluminescence (PL) spectra in region of 1.5-3.5 eV, photoluminescence excitation (PLE) spectra (2.75-5 eV) and anti-stokes luminescence (ASL) spectra were measured at room temperature in KPb2Cl5 (KPC) and RbPb2Br5 (RPB) matrices doped with Er3+ (1%) ions and in KPC doped with Er3++ Yb3+ ions(1:3 ratio concentration). Intraconfigurational f→f transitions are observed in Er3+ ions in most of the cases. The concrete spectrum form is strongly dependent on the excitation energy. Under 980 nm excitation upper Er3+ levels are excited, showing upconversional processes. In case of 313 nm (UV) and 365 nm (VIS) excitation self trapped exciton luminescence was detected in RPB crystal. Additional Yb3+ doping ions strongly increase quantum yield under 980 nm excitation and this doping cause insignificant influence on quantum yield under VIS or UV excitation.

  15. Study of the point defect creation and of the excitonic luminescence in alkali halides irradiated by swift heavy ions

    International Nuclear Information System (INIS)

    Protin, L.

    1994-01-01

    The aim of this experimental thesis is to study the excitonic mechanisms and of the defect creation, in NaCl and KBr, under dense electronic excitations induced by swift heavy ion irradiations. In the first part, we present the main features of the interaction of swift heavy ions with solid targets, and after we review the well known radiolytic processes of the defect creation during X-ray irradiation. In the second chapter, we describe our experimental set-up. In the chapter III, we present our results of the in-situ optical absorption measurements. This results show that defect creation is less sensitive to the temperature than during a classical irradiation. Besides, we observe new mechanisms concerning the defect aggregation. In the chapter IV, we present the results of excitonic luminescence induced by swift by swift heavy ions. We observe that the luminescence yields only change with the highest electronic stopping power. In the chapter V, we perform thermal spike and luminescence yields calculations and we compare the numerical results to the experiments presented in the chapter IV. (author). 121 refs., 65 figs., 30 tabs

  16. Resetting of the luminescence signal in modern riverbed cobbles along the course of the Shiyang River, China

    DEFF Research Database (Denmark)

    Liu, Jinfeng; Cui, Furong; Murray, Andrew Sean

    2018-01-01

    . The infrared stimulated luminescence (IRSL) signal was measured as a function of depth for cobbles of two different lithologies (sandstone and granite). The results show that (i) the bleaching rate of the signal for light-coloured granite is higher than for opaque dark-coloured sandstone, because granite...... is bleached to greater depths than sandstone; (ii) cobble daylight bleaching depths show a downstream increasing trend, with almost all bleaching occurring in the upstream section; and (iii) despite possible abrasion of the upper surface of granite cobbles, the bleaching depth in the upper surface is greater...

  17. Sono-luminescence and nuclear fusion

    International Nuclear Information System (INIS)

    Seife, Ch.; Hilgenfeldt, S.; Lohse, D.

    2002-01-01

    This article presents multi-bubble and single-bubble luminescence. Since long scientists have known that ultra-sound waves could trigger the formation of bubbles in water (phenomenon called cavitation) but in 1930, for the first time experiments showed that these bubbles could emit light in particular conditions. In 1989 F. Gaitan succeeded in trapping a single bubble by using stationary ultra-sound waves, this bubble was exploding 20.000 times per second according to the frequency of the wave while emitting a series of flashes of light. Some scientists thought that the gas inside the bubble could reach very high values of temperature and pressure, and proposed the possibility of nuclear fusion to explain the excess of neutrons that has been evidenced in a cavitation experiment with deuterated acetone. The last part of this article describes the controversy triggered by the article describing this experiment, that was published by 'Science' in march 2002. (A.C.)

  18. Detection of irradiated prawns by photostimulated luminescence

    International Nuclear Information System (INIS)

    Chen, Susu; Saito, Kimie; Hagiwara, Shoji; Todoriki, Setsuko; Nakajima, Mitsutoshi

    2011-01-01

    The purpose of this study was to investigate how photostimulated luminescence (PSL) can be applied to verify whether prawns have been irradiated by analyzing their intestinal tracts. Prawns from five different locations which were irradiated at doses of 1 kGy of γ-radiations were analyzed using the Japanese model PSL system. The results showed that the integrated photon counts of all the irradiated samples exceeded the upper threshold value (T 2 =4000 counts/90 s), whereas those of the non-irradiated samples were blew than the lower threshold value (T 1 =1000 counts/90 s). Moreover, using the other parameters which were decrease of intensity after optically stimulation and increase of intensity by optically stimulation, a clear difference was observed between non-irradiated and 1 kGy irradiated samples. Therefore, the Japanese model PSL system can be used as a screening method for detecting irradiated prawns by analyzing their intestinal tracts. (author)

  19. Luminescent Polymer Electrolyte Composites Using Silica Coated-Y2O3:Eu as Fillers

    Directory of Open Access Journals (Sweden)

    Mikrajuddin Abdullah

    2003-05-01

    Full Text Available Luminescent polymer electrolyte composites composed of silica coated Y2O3:Eu in polyethylene glycol (PEG matrix has been produced by initially synthesizing silica coated Y2O3:Eu and mixing with polyethylene glycol in a lithium salt solution. High luminescence intensity at round 600 nm contributed by electron transitions in Eu3+ (5D0 -> 7F0, 5D0 -> 7F1, and 5D0 -> 7F3 transitions were observed. The measured electrical conductivity was comparable to that reported for polymer electrolyte composites prepared using passive fillers (non luminescent. This approach is therefore promising for production of high intensity luminescent polymer electrolyte composites for use in development of hybrid battery/display.

  20. 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

  1. 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

  2. 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...

  3. Site symmetry and crystal field of Ce{sup 3+} luminescent centres in KMgF{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Yamaga, M. [Department of Electrical and Electronic Engineering, Faculty of Engineering, Gifu University, Gifu (Japan); Honda, M.; Kawamata, N. [Faculty of Science, Naruto University of Education, Naruto (Japan); Fujita, T.; Shimamura, K.; Fukuda, T. [Institute for Materials Research, Tohoku University, Sendai (Japan)

    2001-04-09

    The electron-spin resonance (ESR) spectra of Ce{sup 3+} in KMgF{sub 3} observed at low temperatures (<20 K) show that two tetragonal and two orthorhombic Ce{sup 3+} centres exist in the absence of a cubic centre. These Ce{sup 3+} centres are strongly associated with substitution of Ce{sup 3+} ions for K{sup +} ions with K{sup +}-ion vacancies at three different sites and for a Mg{sup 2+} ion with a vacancy of the nearest neighbour Mg{sup 2+} ion along the [101] direction as charge compensators. The optical absorption spectrum of Ce{sup 3+} in KMgF{sub 3} measured at room temperature consists of two intense broadbands with peaks at 229 and 237 nm, and two weak bands with peaks at 203 and 211 nm corresponding to the transition from the ground state {sup 2}F{sub 5/2} to the 5d{sup 1} excited states of Ce{sup 3+}. The Ce{sup 3+} luminescence spectrum excited at 229 or 237 nm at room temperature is composed of broadbands with double peaks at 265 and 282 nm, which are due to the ground-state splitting between {sup 2}F{sub 5/2} and {sup 2}F{sub 7/2}. The peak of the weak luminescence band excited at a tail (250-280 nm) of the intense absorption bands is shifted to lower energy. The intense and weak Ce{sup 3+} luminescence bands are assigned to Ce{sup 3+} ions substituting for K{sup +} ions away from and near to K{sup +}-ion vacancies, respectively. The luminescence from Ce{sup 3+} ions substituting for Mg{sup 2+} ions could not be observed at room temperature. (author)

  4. Aluminum Nitride Ceramic as an Optically Stimulable Luminescence Dosimeter Plate

    Directory of Open Access Journals (Sweden)

    Go Okada

    2016-04-01

    Full Text Available Photostimulable storage phosphors have been used in a wide range of applications including radiation measurements in one- and two-dimensional spaces, called point dosimetry and radiography. In this work, we report that an aluminum nitride (AlN ceramic plate, which is practically used as a heat sink (SHAPAL®, Tokuyama Corp., Yamaguchi, Japan, shows good optically-stimulated luminescence (OSL properties with sufficiently large signal and capability for imaging applications, and we have characterized the AlN plate for OSL applications. Upon interaction with X-rays, the sample color turns yellowish, due to a radiation-induced photoabsorption band in the UV-blue range below ~500 nm. After irradiating the sample with X-rays, an intense OSL emission can be observed in the UV (360 nm spectral region during stimulation by red light. Although our measurement setup is not optimized, dose detection was confirmed as low as ~3 mGy to over 20 Gy. Furthermore, we have successfully demonstrated that the SHAPAL® AlN ceramic plate has great potential to be used as an imaging plate in radiography.

  5. 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.

  6. Luminescence detection of irradiated foods

    International Nuclear Information System (INIS)

    Sanderson, D.C.W.

    1990-01-01

    The need for forensic tests to identify irradiated foods has been widely recognised at a time of growing international trade in such products and impending changes in UK and EEC legislation to control the process. This paper outlines the requirements for and of such tests, and discusses recent developments in luminescence approaches aimed at meeting the needs of public analysts, retailers and consumers. Detecting whether or not food has been irradiated, and if so to what dose, is one of the challenges which food irradiation poses to the scientist. (author)

  7. Rupture luminescence from natural fibers

    Science.gov (United States)

    Li, W.; Haneman, D.

    1999-12-01

    Fibers of cotton and wool, and samples of paper, have been ruptured in tension in vacuum and in air, and give detectable luminescence in the visible range. All have a common emission peak at around 2.0 eV, which is ascribed to the deexcitation of states excited by the rupture of organic chain molecule bonds. Rubber bands give stronger emission in air, but no emission in vacuum, suggesting the material breaks only at weak interchain bonds. Mohair, cat, and horse hair also give emission in air. The phenomena reveal effects that would occur widely in nature.

  8. 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.

  9. 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.

  10. Photostimulated luminescence, fast method of detection of irradiated foodstuffs

    International Nuclear Information System (INIS)

    Guzik, G.P.; Stachowicz, W.

    2005-01-01

    The principle of pulsed photostimulated luminescence (PPSL) method, description of instrumentation and methodology of measurements are presented. The pathway of operational procedure and testing of the PPSL instrument in the Laboratory for Detection of Irradiated Food of the Institute of Nuclear Chemistry and Technology are described. Attention has been paid to the positives of the new method while some limitation of its application have been also discussed. (author)

  11. Dental diagnostic clinical instrument ('Canary') development using photothermal radiometry and modulated luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, R J; Sivagurunathan, K; Garcia, J; Matvienko, A; Mandelis, A [Center for Advanced Diffusion Wave Technologies (CADIFT), Department of Mechanical and Industrial Engineering, University of Toronto, 5 King' s College Road, Toronto, Ontario, M5S 3G8 (Canada); Abrams, S, E-mail: mandelis@mie.utoronto.c [Quantum Dental Technologies, 748 Briar Hill Avenue, Toronto, Ontario, M6B 1L3 (Canada)

    2010-03-01

    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.

  12. 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.

  13. Role of oxygen concentration distribution and microstructure in luminescent properties of laser-irradiated silicon

    International Nuclear Information System (INIS)

    Zhu, Min; Li, Xiaohong; Li, Guoqiang; Xie, Changxin; Qiu, Rong; Li, Jiawen; Huang, Wenhao

    2015-01-01

    Graphical abstract: Photoluminescence (PL) of monocrystalline silicon irradiated by femtosecond laser pulses was studied. The visible blue luminescence is observed both from the deionized water and air. The position and shape of emission luminescence peaks in the visible range are same at 330 nm. The PL is confirmed to be not merely induced by the oxygen defects or quantum confinement effects, but is commonly decided by the concentration distribution of SiO x and the depth of the surface microstructure. The PL gets strongest only when depth of the surface microstructure is not deeper and the distribution of the shallow SiO x is more intensive. - Highlights: • Different morphologies and compositions of the surface microstructures are formed. • The SiO x concentration and surface microstructure depth commonly decide the PL. • The PL intensity can be controlled by changing the experimental conditions. - Abstract: We study the photoluminescence (PL) of monocrystalline silicon irradiated by femtosecond laser pulses in different environments (deionized water and air) and energy intensities. The fluorescence spectroscopy measurement results indicate that the visible blue luminescence is observed both from the silicon surfaces ablated in the deionized water and air. The more interesting phenomenon is that the position and shape of the emission luminescence peaks in the visible range are substantially the same at the same excitation wavelength 330 nm. Compared with the granular-like microstructure generated on the silicon surface in air, the smaller and stripe-like microstructure is formed in the deionized water as the field emission scanning electron microscope (FESEM) measures. The results of the energy dispersive spectroscopy (EDS) show that silicon and oxygen is the main elemental composition on laser-induced silicon surfaces, and the oxygen content on the sample surfaces formed in air is nearly four times more than that in the deionized water. The studies confirm

  14. 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)

  15. Fluorescence measurements show stronger cold inhibition of photosynthetic light reactions in Scots pine compared to Norway spruce as well as during spring compared to autumn.

    Science.gov (United States)

    Linkosalo, Tapio; Heikkinen, Juha; Pulkkinen, Pertti; Mäkipää, Raisa

    2014-01-01

    We studied the photosynthetic activity of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies [L.] Karst) in relation to air temperature changes from March 2013 to February 2014. We measured the chlorophyll fluorescence of approximately 50 trees of each species growing in southern Finland. Fluorescence was measured 1-3 times per week. We began by measuring shoots present in late winter (i.e., March 2013) before including new shoots once they started to elongate in spring. By July, when the spring shoots had achieved similar fluorescence levels to the older ones, we proceeded to measure the new shoots only. We analyzed the data by fitting a sigmoidal model containing four parameters to link sliding averages of temperature and fluorescence. A parameter defining the temperature range over which predicted fluorescence increased most rapidly was the most informative with in describing temperature dependence of fluorescence. The model generated similar fluorescence patterns for both species, but differences were observed for critical temperature and needle age. Down regulation of the light reaction was stronger in spring than in autumn. Pine showed more conservative control of the photosynthetic light reactions, which were activated later in spring and more readily attenuated in autumn. Under the assumption of a close correlation of fluorescence and photosynthesis, spruce should therefore benefit more than pine from the increased photosynthetic potential during warmer springs, but be more likely to suffer frost damage with a sudden cooling following a warm period. The winter of 2013-2014 was unusually mild and similar to future conditions predicted by global climate models. During the mild winter, the activity of photosynthetic light reactions of both conifers, especially spruce, remained high. Because light levels during winter are too low for photosynthesis, this activity may translate to a net carbon loss due to respiration.

  16. Fluorescence measurements show stronger cold inhibition of photosynthetic light reactions in Scots pine compared to Norway spruce as well as during spring compared to autumn

    Directory of Open Access Journals (Sweden)

    Tapio eLinkosalo

    2014-06-01

    Full Text Available We studied the photosynthetic activity of Scots pine (Pinus sylvestris L. and Norway spruce (Picea abies [L.] Karst in relation to air temperature changes from March 2013 to February 2014. We measured the chlorophyll fluorescence of approximately 50 trees of each species growing in southern Finland. Fluorescence was measured 13 times per week. We began by measuring shoots present in late winter (i.e., March 2013 before including new shoots once they started to elongate in spring. By July, when the spring shoots had achieved similar fluorescence levels to the older ones, we proceeded to measure the new shoots only.We analysed the data by fitting a sigmoidal model containing four parameters to link sliding averages of temperature and fluorescence. A parameter defining the temperature range over which predicted fluorescence increased most rapidly was the most informative with in describing temperature dependence of fluorescence.The model generated similar fluorescence patterns for both species, but differences were observed for critical temperature and needle age. Down regulation of the light reaction was stronger in spring than in autumn. Pine showed more conservative control of the photosynthetic light reactions, which were activated later in spring and more readily attenuated in autumn. Under the assumption of a close correlation of fluorescence and photosynthesis, spruce should therefore benefit more than pine from the increased photosynthetic potential during warmer springs, but be more likely to suffer frost damage with a sudden cooling following a warm period. The winter of 20132014 was unusually mild and similar to future conditions predicted by global warming models. During the mild winter, the activity of photosynthetic light reactions of both conifers, especially spruce, remained high. Because light levels during winter are too low for photosynthesis, this activity may translate to a net carbon loss due to respiration.

  17. Ion beam induced luminescence: Relevance to radiation induced bystander effects

    Science.gov (United States)

    Ahmad, S. B.; McNeill, F. E.; Byun, S. H.; Prestwich, W. V.; Seymour, C.; Mothersill, C. E.

    2012-10-01

    The aim of this work is quantify the light emitted as a result of charged particle interaction in materials which may be of relevance to radiation induced "bystander effects" studies. We have developed a system which employs single photon counting to measure the light emitted from samples irradiated under vacuum by a charged particle beam. The system uses a fast photomultiplier tube with a peak cathode response at 420 nm. It has been tested in a proof-of-principle experiment using polystyrene targets. Light output, as a result of irradiation, was measured. The luminescence yield appears to have a non-linear behavior with the incident ion fluence: it rises exponentially to an asymptotic value. The target was irradiated with beam energies varying from 1 to 2 MeV and showed saturation at or before an incident fluence rate of 3 × 1013 H+/cm2 s. The average saturation value for the photon output was found to be 40 × 106 cps. Some measurements were performed using filters to study the emission at specific wavelengths. In the case of filtered light measurements, the photon output was found to saturate at 28 × 103, 10 × 106, and 35 × 106 cps for wavelengths of 280 ± 5 nm, 320 ± 5 nm and 340 ± 5 nm respectively. The light output reaches a maximum value because of damage induced in the polymer. Our measurements indicate a "damage cross section" of the order of 10-14 cm2. The average radiant intensity was found to increase at wavelengths of 280 and 320 nm when the proton energy was increased. This was not found to occur at 340 nm. In conclusion, the light emission at specific wavelengths was found to depend upon the incident proton fluence and the proton energy. The wavelengths of the emitted light measured in this study have significance for the understanding of radiation induced bystander effects.

  18. Luminescence decay of S Zn::Ag and O Zn:Ga scintillation detectors excited by a pulsed laser

    International Nuclear Information System (INIS)

    Romero, L.; Campos, J.

    1981-01-01

    In the present work a high sensitivity experimental set up for luminescence decay measurements in the 1 0 - 1 sec range has been developed. As an application, luminescence light decay In S Zn:Ag and 0Zn:Ga after excitation by a pulsed N 2 laser has been measured. In SZnrAg, measurements of total light decay was compared with donor acceptor pairs theory. In both substances, spectral evolution in the first 15 sec was investigated. (Author) 4 refs

  19. The dependence of luminescence lifetimes on additive irradiation in natural sedimentary quartz: sands from Santa Elina, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Chithambo, M.L. [Department of Physics and Electronics, Rhodes University, P.O. Box 94, Grahamstown 6140 (South Africa); Ogundare, F.O. [Department of Physics, University of Ibadan, Ibadan (Nigeria); Feathers, J. [Department of Anthropology, University of Washington, P.O. Box 353100, Seattle, WA 98195-3100 (United States); Hong, D.G. [Department of Physics, Kangwon National University, Chuncheon, Kangwon-Do 200-701 (Korea)

    2008-07-01

    Time-resolved luminescence and its component lifetimes have been measured from natural quartz in order to interpret the associated dynamics of luminescence emission. The influence of beta irradiation, and measurement temperature on the lifetimes have been investigated and parameters of the kinetics involved calculated. The results are explained by considering the extent of non-radiative processes and the role of charge transfer between several types of luminescence centres. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. The dependence of luminescence lifetimes on additive irradiation in natural sedimentary quartz: sands from Santa Elina, Brazil

    International Nuclear Information System (INIS)

    Chithambo, M.L.; Ogundare, F.O.; Feathers, J.; Hong, D.G.

    2008-01-01

    Time-resolved luminescence and its component lifetimes have been measured from natural quartz in order to interpret the associated dynamics of luminescence emission. The influence of beta irradiation, and measurement temperature on the lifetimes have been investigated and parameters of the kinetics involved calculated. The results are explained by considering the extent of non-radiative processes and the role of charge transfer between several types of luminescence centres. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Preparation, characterization, and luminescence properties of dysprosium perchlorate with MABA-Si and phen or dipy complexes as well as SiO{sub 2}@Dy(MABA-Si)L core-shell structure nanometermeter luminescent composites

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wen-Xian, E-mail: nmglwx@163.com [College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021 (China); Zheng, Yu-Shan [Inner Mongolia Autonomous Region Product Quality Inspection Institute, Hohhot 010010 (China); Cao, Xiao-fang; Bai, Juan; Fu, Zhi-Fang; Bao, Jin-Rong; Li, Yi-Lian [College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021 (China)

    2016-10-15

    Two novel ternary rare earth complexes Dy(MABA-Si)·L{sub 2}(ClO{sub 4}){sub 3}·2H{sub 2}O (L= Phen or Dipy) were prepared using HOOCC{sub 6}H{sub 4}N(CONH(CH{sub 2}){sub 3}Si-(OCH{sub 2}CH{sub 3}){sub 3}){sub 2} which was abbreviated or denoted as MABA-Si. MABA-Si was the first ligand, L was the second ligand. The corresponding two SiO{sub 2}@Dy(MABA-Si)L nanometermeter luminescent composites were synthesized as well, and the silica spheres is the core, and the ternary rare earth complex Dy(MABA-Si)·L{sub 2}(ClO{sub 4}){sub 3}·2H{sub 2}O was the shell layer, who was abbreviated or denoted as Dy((MABA-Si)L). The ternary complexes have been characterized by element analysis, molar conductivity, IR spectra and {sup 1}HNMR spectra. The results showed that the chemical formula of the complex was Dy(MABA-Si)·L{sub 2}(ClO{sub 4}){sub 3}·2H{sub 2}O. The fluorescent spectra illustrated that the complexes displayed its characteristic luminescence in solid state, and the luminescence was superior than Dy{sup 3+}. The core-shell structure of SiO{sub 2}@Dy(MABA-Si)L nanometermeter luminescent composite was characterized by SEM, TEM and IR spectra. Based on the SEM photographs, the core-shell structure particles showed its regular microstructure including smooth surface, and good dispersity. The ternary complex coated on the mono-dispersed SiO{sub 2} spheres by self-assembly. The fluorescent spectra illustrated that the core-shell structure of SiO{sub 2}@Dy(MABA-Si)L nanometermeter luminescent composites exhibited stronger fluorescent than the ternary complexes. The fluorescence lifetime of the complexes and core-shell structure composites was measured as well.

  2. 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.

  3. 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

    experimentally measured luminescence signals originate in a single trap, or in multiple traps.

  4. Stress determination in thermally grown alumina scales using ruby luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Renusch, D.; Veal, B.W.; Koshelev, I.; Natesan, K.; Grimsditch [Argonne National Lab., IL (United States); Hou, P.Y. [Lawrence Berkeley Lab., CA (United States)

    1996-06-01

    By exploiting the strain dependence of the ruby luminescence line, we have measured the strain in alumina scales thermally grown on Fe-Cr- Al alloys. Results are compared and found to be reasonably consistent with strains determined using x rays. Oxidation studies were carried out on alloys Fe - 5Cr - 28Al and Fe - 18Cr - 10Al (at.%). Significantly different levels of strain buildup were observed in scales on these alloys. Results on similar alloys containing a ``reactive element`` (Zr or Hf) in dilute quantity are also presented. Scales on alloys containing a reactive element (RE) can support significantly higher strains than scales on RE-free alloys. With the luminescence technique, strain relief associated with spallation thresholds is readily observed.

  5. Freestanding silicon quantum dots: origin of red and blue luminescence.

    Science.gov (United States)

    Gupta, Anoop; Wiggers, Hartmut

    2011-02-04

    In this paper, we studied the behavior of silicon quantum dots (Si-QDs) after etching and surface oxidation by means of photoluminescence (PL) measurements, Fourier transform infrared spectroscopy (FTIR) and electron paramagnetic resonance spectroscopy (EPR). We observed that etching of red luminescing Si-QDs with HF acid drastically reduces the concentration of defects and significantly enhances their PL intensity together with a small shift in the emission spectrum. Additionally, we observed the emergence of blue luminescence from Si-QDs during the re-oxidation of freshly etched particles. Our results indicate that the red emission is related to the quantum confinement effect, while the blue emission from Si-QDs is related to defect states at the newly formed silicon oxide surface.

  6. Ion beam induced luminescence characterisation of CVD diamond films

    Energy Technology Data Exchange (ETDEWEB)

    Bettiol, A A; Gonon, P; Jamieson, D N [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1997-12-31

    The characterisation of the band structure properties of materials and devices by ion microprobe techniques has been made possible at the Melbourne MeV ion microprobe facility with the development of Ion Beam Induced Luminescence (IBIL). A number of diamond films grown by Microwave Plasma Chemical Vapour Deposition (MPCVD) on silicon substrates are analysed. A preliminary study of the luminescence properties of these samples has revealed information not previously obtainable via traditional microprobe techniques. The optical effects of incorporating dopants during the deposition process is determined using IBIL. The presence of trace element impurities introduced during growth is examined by Particle Induced X-ray Emission (PIXE), and a measurement of the film thickness is made using Rutherford Backscattering Spectrometry (RBS). 7 refs., 2 figs.

  7. Ion beam induced luminescence characterisation of CVD diamond films

    Energy Technology Data Exchange (ETDEWEB)

    Bettiol, A.A.; Gonon, P.; Jamieson, D.N. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    The characterisation of the band structure properties of materials and devices by ion microprobe techniques has been made possible at the Melbourne MeV ion microprobe facility with the development of Ion Beam Induced Luminescence (IBIL). A number of diamond films grown by Microwave Plasma Chemical Vapour Deposition (MPCVD) on silicon substrates are analysed. A preliminary study of the luminescence properties of these samples has revealed information not previously obtainable via traditional microprobe techniques. The optical effects of incorporating dopants during the deposition process is determined using IBIL. The presence of trace element impurities introduced during growth is examined by Particle Induced X-ray Emission (PIXE), and a measurement of the film thickness is made using Rutherford Backscattering Spectrometry (RBS). 7 refs., 2 figs.

  8. 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)

  9. Anodal Transcranial Direct Current Stimulation Shows Minimal, Measure-Specific Effects on Dynamic Postural Control in Young and Older Adults: A Double Blind, Sham-Controlled Study.

    Science.gov (United States)

    Craig, Chesney E; Doumas, Michail

    2017-01-01

    We investigated whether stimulating the cerebellum and primary motor cortex (M1) using transcranial direct current stimulation (tDCS) could affect postural control in young and older adults. tDCS was employed using a double-blind, sham-controlled design, in which young (aged 18-35) and older adults (aged 65+) were assessed over three sessions, one for each stimulatory condition-M1, cerebellar and sham. The effect of tDCS on postural control was assessed using a sway-referencing paradigm, which induced platform rotations in proportion to the participant's body sway, thus assessing sensory reweighting processes. Task difficulty was manipulated so that young adults experienced a support surface that was twice as compliant as that of older adults, in order to minimise baseline age differences in postural sway. Effects of tDCS on postural control were assessed during, immediately after and 30 minutes after tDCS. Additionally, the effect of tDCS on corticospinal excitability was measured by evaluating motor evoked potentials using transcranial magnetic stimulation immediately after and 30 minutes after tDCS. Minimal effects of tDCS on postural control were found in the eyes open condition only, and this was dependent on the measure assessed and age group. For young adults, stimulation had only offline effects, as cerebellar stimulation showed higher mean power frequency (MPF) of sway 30 minutes after stimulation. For older adults, both stimulation conditions delayed the increase in sway amplitude witnessed between blocks one and two until stimulation was no longer active. In conclusion, despite tDCS' growing popularity, we would caution researchers to consider carefully the type of measures assessed and the groups targeted in tDCS studies of postural control.

  10. 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.

  11. 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.

  12. Na-rich feldspar as a luminescence dosimeter in infrared stimulated luminescence (IRSL) dating

    DEFF Research Database (Denmark)

    Sohbati, Reza; Murray, Andrew; Jain, Mayank

    2013-01-01

    on geological origin and erosion history, but the dosimetry of K-rich feldspar grains extracted from rocks is complicated because the internal dose rate is very dependent on the original feldspar grain size. The in situ grain size information is lost during the crushing process used to separate the grains...... settings for which independent age control is available. The blue and yellow luminescence emissions are measured for IR stimulation at 50 °C (IR50), and post-IR IR stimulation at 290 °C (pIRIR290). Thermal stability experiments imply that the corresponding signals in both emissions have comparable thermal...... stabilities and that all signals have similar recombination kinetics and are thermally stable over geological timescales. The IR50 doses measured using blue and yellow emissions are similar to or lower than quartz doses while pIRIR290 blue doses are higher than those from yellow emission and quartz doses...

  13. Synthesis, structural and luminescence properties of Bi3+ co-doped Y2Sn2O7:Tb nanoparticles

    International Nuclear Information System (INIS)

    Nigam, S.; Sudarsan, V.; Vatsa, R.K.

    2010-01-01

    Full text: In recent years, advanced materials derived from Pyrochlore-type oxides (A 2 B 2 O 7 ) have been of extensive scientific and technological interest. Chemical substitution of A or B sites of pyrochlore oxide by rare earth ions is a widely used approach to prepare thermally stable, lanthanide ion doped luminescent materials. Due to the higher symmetry around the A and B sites in the lattice lanthanide ions like Eu 3+ and Tb 3+ when incorporated at the A or B sites give very poor luminescence. This problem can be avoided by incorporating other ions like Bi 3+ in the lattice so that the lattice gets distorted and luminescent intensity from the lanthanide ions increases. The present study deals with the synthesis and characterization of Bi 3+ co-doped Y 2 Sn 2 O 7 :Tb nanoparticles. For the preparation of Tb 3+ and Bi 3+ doped Y 2 Sn 2 O 7 nano-materials, Sn metal, Bi(NO 3 ) 3 , Tb 4 O 7 , Y 2 CO 3 , were used as starting materials. The solution containing Y 3+ , Sn 4+ ,and Bi 3+ -Tb 3+ in ethylene glycol medium was slowly heated up to 120 deg C and then subjected to urea hydrolysis. The obtained precipitate after washing was heated to 700 deg C. As prepared samples are amorphous in nature and 700 deg C heated sample showed well crystalline pyrochlore structure as revealed by the XRD studies. Average particles size is calculated from the width of the X-ray diffraction peaks and found to be ∼ 5 nm. TEM images of the nanoparticles obtained at 700 deg C shows very fine spherical particles having a diameter in the range of 2-5 nm. Luminescence measurements were carried out for as prepared and 700 deg C heated samples of 2.5%Tb doped Y 2 Sn 2 O 7 nanoparticles. Green emission characteristic 5 D 4 7 F 5 transition of Tb 3+ has been observed from as prepared sample but on heating to 700 deg C the emission characteristic of Tb 3+ ions got completely removed . However, there is a significant improvement in Tb 3+ emission from 2.5% Bi 3+ co-doped Y 2 Sn 2 O 7 :Tb 3

  14. 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

  15. 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

  16. Co-doping effects on luminescence and scintillation properties of Ce doped Lu3Al5O12 scintillator

    International Nuclear Information System (INIS)

    Kamada, Kei; Nikl, Martin; Kurosawa, Shunsuke; Beitlerova, Alena; Nagura, Aya; Shoji, Yasuhiro; Pejchal, Jan; Ohashi, Yuji; Yokota, Yuui; Yoshikawa, Akira

    2015-01-01

    The Mg, Ca, Sr and Ba 200 ppm co-doped Ce:Lu 3 Al 5 O 12 single crystals were prepared by micro pulling down method. Absorption and luminescence spectra were measured together with several other scintillation characteristics, namely the scintillation decay and light yield to reveal the effect of the co-doping. The scintillation decays were accelerated by both Mg and Ca co-dopants. The Mg co-doped samples showed the fastest decay and the highest light yield among the co-doped samples

  17. Luminescence of Quantum Dots by Coupling with Nonradiative Surface Plasmon Modes in a Scanning Tunneling Microscope

    International Nuclear Information System (INIS)

    Romero, M.J.; van de Lagemaat, J.

    2009-01-01

    The electronic coupling between quantum dots (QDs) and surface plasmons (SPs) is investigated by a luminescence spectroscopy based on scanning tunneling microscopy (STM). We show that tunneling luminescence from the dot is excited by coupling with the nonradiative plasmon mode oscillating at the metallic tunneling gap formed during the STM operation. This approach to the SP excitation reveals aspects of the SP-QD coupling not accessible to the more conventional optical excitation of SPs. In the STM, luminescence from the dot is observed when and only when the SP is in resonance with the fundamental transition of the dot. The tunneling luminescence spectrum also suggests that excited SP-QD hybrid states can participate in the excitation of QD luminescence. Not only the SP excitation regulates the QD luminescence but the presence of the dot at the tunneling gap imposes restrictions to the SP that can be excited in the STM, in which the SP cannot exceed the energy of the fundamental transition of the dot. The superior SP-QD coupling observed in the STM is due to the tunneling gap acting as a tunable plasmonic resonator in which the dot is fully immersed.

  18. 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.

  19. 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.

  20. 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.

  1. Facile synthesis of luminescent and amorphous La2O3-ZrO2:Eu3+ nanofibrous membranes with robust softness

    Science.gov (United States)

    Han, Weidong; Ding, Bin; Park, Mira; Cui, Fuhai; Ghouri, Zafar Khan; Saud, Prem Singh; Kim, Hak-Yong

    2015-08-01

    Novel luminescent and amorphous La2O3-ZrO2:Eu3+ (LZE) nanofibrous membranes with robust softness are fabricated for the first time via a facile electrospinning technique. By incorporating zirconium oxide, the as-prepared lanthanum oxide nanofibrous membranes can be dramatically changed from extreme fragility to robust softness. Meanwhile, the softness and luminescent performance of LZE nanofibrous membranes can be finely controlled by regulating the doping concentration of zirconium oxide and europium in lanthanum oxide nanofibers. Additionally, the crystal structure analysis using X-ray diffractometer and high resolution transmission electron microscopy measurements have confirmed the correlation between the amorphous structure and softness. Furthermore, LZE membranes show the characteristic emission of Eu3+ corresponding to 5D0, 1, 2-7F0, 1, 2, 3, 4 transitions due to an efficient energy transfer from O2- to Eu3+. The LZE nanofibrous membranes with the optimum doping Eu3+ concentration of 3 mol% exhibit excellent softness and luminescent properties, which make the materials to have potential applications in fluorescent lamps and field emission displays.Novel luminescent and amorphous La2O3-ZrO2:Eu3+ (LZE) nanofibrous membranes with robust softness are fabricated for the first time via a facile electrospinning technique. By incorporating zirconium oxide, the as-prepared lanthanum oxide nanofibrous membranes can be dramatically changed from extreme fragility to robust softness. Meanwhile, the softness and luminescent performance of LZE nanofibrous membranes can be finely controlled by regulating the doping concentration of zirconium oxide and europium in lanthanum oxide nanofibers. Additionally, the crystal structure analysis using X-ray diffractometer and high resolution transmission electron microscopy measurements have confirmed the correlation between the amorphous structure and softness. Furthermore, LZE membranes show the characteristic emission of Eu3

  2. 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.

  3. Shock-induced luminescence from Z-cut lithium niobate

    International Nuclear Information System (INIS)

    Brannon, P.J.; Morris, R.W.; Asay, J.R.

    1985-01-01

    Shock-induced luminescence from lithium niobate has been studied in the stress range 1.6--21.0 GPa. Both fast-framing photography and five-channel optical pyrometry were used to observe the luminescence. The framing photography showed that the emission pattern is heterogeneous for stresses just above the dynamic yield point. A further increase of the stress resulted in a pattern which was essentially homogeneous to within the experimental spatial resolution of about 30 μm. Narrowband filters and photomultiplier tubes were used in the optical pyrometry experiments. A broadband spectrum with a peak near 700 nm was observed. A plot of the energy dissipated by the shock versus shock stress correlates very well with a plot of the 700-nm intensity versus shock stress. The mechanism for light emission in lithium niobate appears to be closely related to the dynamic yielding process

  4. Luminescence and luminescence quenching of Sr{sub 3}Lu{sub 2}(Si{sub 3}O{sub 9}){sub 2}:Ce{sup 3+} phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Mikalauskaite, I.; Raudonyte-Svirbutaviciene, E. [Institute of Chemistry, Faculty of Chemistry and Geosciences, Vilnius University, Naugarduko 24, LT-03225 Vilnius (Lithuania); Linkeviciute, A. [State Research Institute, Centre for Physical Sciences and Technology, Sauletekio Avenue 3, LT-10257 Vilnius (Lithuania); Urbonas, M. [Institute of Chemistry, Faculty of Chemistry and Geosciences, Vilnius University, Naugarduko 24, LT-03225 Vilnius (Lithuania); Katelnikovas, A., E-mail: arturas.katelnikovas@chf.vu.lt [Institute of Chemistry, Faculty of Chemistry and Geosciences, Vilnius University, Naugarduko 24, LT-03225 Vilnius (Lithuania)

    2017-04-15

    A series of near-UV to blue emitting Sr{sub 3}Lu{sub 2}(Si{sub 3}O{sub 9}){sub 2}:Ce{sup 3+} phosphors were prepared by a solid state reaction. The optical properties of synthesized phosphors were investigated as a function of Ce{sup 3+} concentration and temperature. These luminescent materials strongly absorb UV radiation shorter than 360 nm. The optimal Ce{sup 3+} concentration was 0.1% (external quantum efficiency ca. 45%). Temperature dependent measurements showed that Sr{sub 3}Lu{sub 2}(Si{sub 3}O{sub 9}){sub 2}:Ce{sup 3+} phosphors possess good thermal stability and loses only about 40% to 50% of initial intensity in the temperature range of 77–500 K depending on activator concentration.

  5. 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

  6. submitter Preparation and luminescence properties of ZnO:Ga – polystyrene composite scintillator

    CERN Document Server

    Burešová, Hana; Turtos, Rosana Martinez; Jarý, Vítězslav; Mihóková, Eva; Beitlerová, Alena; Pjatkan, Radek; Gundacker, Stefan; Auffray, Etiennette; Lecoq, Paul; Nikl, Martin; Čuba, Václav

    2016-01-01

    Highly luminescent ZnO:Ga-polystyrene composite (ZnO:Ga-PS) with ultrafast subnanosecond decay was prepared by homogeneous embedding the ZnO:Ga scintillating powder into the scintillating organic matrix. The powder was prepared by photo-induced precipitation with subsequent calcination in air and Ar/H2 atmospheres. The composite was subsequently prepared by mixing the ZnO:Ga powder into the polystyrene (10 wt% fraction of ZnO:Ga) and press compacted to the 1 mm thick pellet. Luminescent spectral and kinetic characteristics of ZnO:Ga were preserved. Radioluminescence spectra corresponded purely to the ZnO:Ga scintillating phase and emission of polystyrene at 300-350 nm was absent. These features suggest the presence of non-radiative energy transfer from polystyrene host towards the ZnO:Ga scintillating phase which is confirmed by the measurement of X-ray excited scintillation decay with picosecond time resolution. It shows an ultrafast rise time below the time resolution of the experiment (18 ps) and a single-...

  7. 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.

  8. Determination of Silver Ions Toxicity in Short-Term and Long-Term Experiments Using a Luminescent Recombinant Strain of E. coli

    Directory of Open Access Journals (Sweden)

    Tatiana P. Yudina

    2013-01-01

    Full Text Available The effects of silver ions on the luminescent recombinant strain of Escherichia coli carrying luxCDABE operon of Vibrio fischeri were investigated. The toxicity of silver ions was determined in 30 minutes and in chronic 24 hours experiments. Changes in the luminescence intensity and in the growth rate of bacteria were considered as a measure of silver ions toxicity within the range of concentrations applied. The effect of silver ions was demonstrated to be strongly dependent on the concentration of bacteria and on the medium composition. EC50 values were 0.018 mg/l after 30 min exposure and 0.014 mg/l after 10 hours of bacterial growth. Comparison of two modifications of the experiment showed that silver ions have a strong non-specific toxicity, as well as a specific effect on bacterial cells

  9. Optically stimulated luminescence in retrospective dosimetry

    International Nuclear Information System (INIS)

    Boetter-Jensen, L.; Murray, A.S.

    2002-01-01

    Since the beginning of the 1990s the exploration of optically stimulated luminescence in retrospective accident dosimetry has driven an intensive investigation and development programme at Ris deg. into measurement facilities and techniques. This paper reviews some of the outcomes of this programme, including the evaluation of the single-aliquot regenerative-dose measurement protocol with brick quartz and the determination of dose-depth profiles in building materials as a guide to determining the mean energy of the incident radiation. Investigations into heated materials are most advanced, and a lower detection limit for quartz extracted from Chernobyl bricks was determined to be <10 mGy. The first results from the measurement of doses in unheated building materials such as mortar and concrete are also discussed. Both small-aliquot and single-grain techniques have been used to assess accident doses in these cement based building materials more commonly found in workplaces. Finally some results of a preliminary investigation of the OSL properties of household chemicals are discussed with reference to their potential as accident dosemeters. (author)

  10. Luminescence properties of Ce3+ doped gadolinium-calcium-silicaborate glass scintillator

    International Nuclear Information System (INIS)

    Park, J.M.; Ha, D.H.; Kaewjeang, S.; Maghanemi, U.; Kothan, S.; Kaewkhao, J.; Kim, H.J.

    2016-01-01

    In this work, the Ce 3+ doped gadolinium-calcium-silicaborate glass scintillators of the composition ratio 25Gd 2 O 3 :10CaO:10SiO 2 :(55−x)B 2 O 3 :xCeF 3 , have been fabricated by using the melt-quenching technique. The doping concentration of the Ce 3+ was varied from 0.05 mol% to 2.5 mol%. The 4f-5d transition of the Ce 3+ allowed scintillation with a fast decay time. The absorption spectrum, X-ray induced emission spectrum, photo luminescence spectrum, laser luminescence spectrum and decay time of the scintillators were measured for studying the luminescence properties. From the X-ray induced emission spectrum result, we checked the trend between doping concentration and light yield. The laser induced luminescence spectrum was measured while changing the temperature from 300 K to 10 K. We also measured the decay time by using the laser excitation of the 0.15 mol% Ce 3+ doped glass scintillator. - Highlights: • Ce 3+ doped gadolinium-calcium-silicaborate glass scintillators were developed. • Glass is easily fabricated with large sizes and various doping materials. • The luminescence properties are studied by using various radiation sources. • The light yield and decay time were measured at low temperature. • One decay time component is found.

  11. A CMOS Luminescence Intensity and Lifetime Dual Sensor Based on Multicycle Charge Modulation.

    Science.gov (United States)

    Fu, Guoqing; Sonkusale, Sameer R

    2018-06-01

    Luminescence plays an important role in many scientific and industrial applications. This paper proposes a novel complementary metal-oxide-semiconductor (CMOS) sensor chip that can realize both luminescence intensity and lifetime sensing. To enable high sensitivity, we propose parasitic insensitive multicycle charge modulation scheme for low-light lifetime extraction benefiting from simplicity, accuracy, and compatibility with deeply scaled CMOS process. The designed in-pixel capacitive transimpedance amplifier (CTIA) based structure is able to capture the weak luminescence-induced voltage signal by accumulating photon-generated charges in 25 discrete gated 10-ms time windows and 10-μs pulsewidth. A pinned photodiode on chip with 1.04 pA dark current is utilized for luminescence detection. The proposed CTIA-based circuitry can achieve 2.1-mV/(nW/cm 2 ) responsivity and 4.38-nW/cm 2 resolution at 630 nm wavelength for intensity measurement and 45-ns resolution for lifetime measurement. The sensor chip is employed for measuring time constants and luminescence lifetimes of an InGaN-based white light-emitting diode at different wavelengths. In addition, we demonstrate accurate measurement of the lifetime of an oxygen sensitive chromophore with sensitivity to oxygen concentration of 7.5%/ppm and 6%/ppm in both intensity and lifetime domain. This CMOS-enabled oxygen sensor was then employed to test water quality from different sources (tap water, lakes, and rivers).

  12. Development of optically stimulated luminescence techniques using natural minerals and ceramics, and their application to retrospective dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Boetter-Jensen, L

    2000-09-01

    This thesis summarises research and development of optically stimulated luminescence (OSL) and its applications by the author at Risoe National Laboratory, up to 1999. These developments have been directed primarily at retrospective accident dosimetry and luminescence dating. Experimental investigations include the studies of OSL properties of the natural minerals quartz and feldspars and the artificial materials porcelain and aluminium oxide (Al{sub 2}O{sub 3}). Blue light emitting diodes and infrared laser diodes are shown to provide simple and practical alternatives to broad-band light and visible laser stimulation. The development of OSL apparatus designed for the rapid measurement of single grains of phosphors also opens up a new area of luminescence measurement, allowing the detailed examination of dose distributions within a multiple-grain sample. This is of particular importance to the studies of incompletely reset geological sediments, and to accident dosimetry measurements using unheated materials. Al{sub 2}O{sub 3}:C single crystals are tested as environmental OSL dosemeters for assessing both the natural background photon radiation dose rates in the field and the natural dose rates inside bricks collected for accident dose evaluation. Environmental doses of the order of few {mu}Gy are measured with high precision. UV photo-stimulated luminescence spectra obtained from porcelain samples are used to confirm that the main component responsible for the OSL signal from porcelain is Al{sub 2}O{sub 3}. OSL single-aliquot regenerative-dose (SAR) techniques are used with quartz extracted from Chernobyl bricks to determine the accrued dose after the accident. This has improved the measurement precision significantly, from about 5-6 % using traditional methods to now less than 2 %. Depth-dose profiles measured in Chernobyl bricks are compared with those obtained in the laboratory using different gamma sources and these comparisons show that the average energy of

  13. Development of optically stimulated luminescence techniques using natural minerals and ceramics, and their application to retrospective dosimetry

    International Nuclear Information System (INIS)

    Boetter-Jensen, L.

    2000-09-01

    This thesis summarises research and development of optically stimulated luminescence (OSL) and its applications by the author at Risoe National Laboratory, up to 1999. These developments have been directed primarily at retrospective accident dosimetry and luminescence dating. Experimental investigations include the studies of OSL properties of the natural minerals quartz and feldspars and the artificial materials porcelain and aluminium oxide (Al 2 O 3 ). Blue light emitting diodes and infrared laser diodes are shown to provide simple and practical alternatives to broad-band light and visible laser stimulation. The development of OSL apparatus designed for the rapid measurement of single grains of phosphors also opens up a new area of luminescence measurement, allowing the detailed examination of dose distributions within a multiple-grain sample. This is of particular importance to the studies of incompletely reset geological sediments, and to accident dosimetry measurements using unheated materials. Al 2 O 3 :C single crystals are tested as environmental OSL dosemeters for assessing both the natural background photon radiation dose rates in the field and the natural dose rates inside bricks collected for accident dose evaluation. Environmental doses of the order of few μGy are measured with high precision. UV photo-stimulated luminescence spectra obtained from porcelain samples are used to confirm that the main component responsible for the OSL signal from porcelain is Al 2 O 3 . OSL single-aliquot regenerative-dose (SAR) techniques are used with quartz extracted from Chernobyl bricks to determine the accrued dose after the accident. This has improved the measurement precision significantly, from about 5-6 % using traditional methods to now less than 2 %. Depth-dose profiles measured in Chernobyl bricks are compared with those obtained in the laboratory using different gamma sources and these comparisons show that the average energy of the accident radiation was

  14. A Wide Spectral Range Reflectance and Luminescence Imaging System

    Directory of Open Access Journals (Sweden)

    Tapani Hirvonen

    2013-10-01

    Full Text Available In this study, we introduce a wide spectral range (200–2500 nm imaging system with a 250 μm minimum spatial resolution, which can be freely modified for a wide range of resolutions and measurement geometries. The system has been tested for reflectance and luminescence measurements, but can also be customized for transmittance measurements. This study includes the performance results of the developed system, as well as examples of spectral images. Discussion of the system relates it to existing systems and methods. The wide range spectral imaging system that has been developed is however highly customizable and has great potential in many practical applications.

  15. Optical spectroscopy and luminescence properties of Ho3+ doped zinc fluorophosphate (ZFP) glasses for green luminescent device applications

    Science.gov (United States)

    Reddy Prasad, V.; Damodaraiah, S.; Ratnakaram, Y. C.

    2018-04-01

    Ho3+ doped zinc fluorophosphate (ZFP) glasses with molar chemical compositions, (60-x) NH4H2PO4+20ZnO+10BaF2+10NaF+xHo2O3 (where x = 0.1, 0.3, 0.5, 1.0 and 1.5 mol%) were prepared by melt quenching technique. These glasses were characterized through physical, structural, optical, excitation, luminescence and decay curve analysis. From the absorption spectra, spectral intensities (fexp and fcal), Judd-Ofelt intensity parameters (Ω2, Ω4 and Ω6), radiative transition probabilities (AT), radiative lifetimes (τR) and branching ratios (βR) were evaluated for all Ho3+ doped ZFP glass matrices. From the photoluminescence spectra, peak stimulated emission cross-sections (σP) were calculated for all Ho3+ doped ZFP glasses. The Ho3+ doped ZFP glasses show strong green emission at 545 nm and red emission at 656 nm under excitation, 450 nm. The measured lifetimes (τmeas) of (5S2)5F4 level of Ho3+ doped ZFP glasses were obtained from decay profiles. The CIE color coordinates of Ho3+ doped ZFP glasses were calculated from emission spectra and 1.0 mol% of Ho3+ doped ZFP glass matrix gives green emission. Hence, these results confirm that the Ho3+ doped ZFP glasses could be considered as a promising candidate for visible green laser applications.

  16. Three-dimensional micro-printing of temperature sensors based on up-conversion luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Wickberg, Andreas; Mueller, Jonathan B. [Institute of Applied Physics and DFG-Center for Functional Nanostructures, Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); Mange, Yatin J.; Nann, Thomas [Ian Wark Research Institute, University of South Australia, Mawson Lakes Blvd, Adelaide, SA 5095 (Australia); Fischer, Joachim [Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); Wegener, Martin [Institute of Applied Physics and DFG-Center for Functional Nanostructures, Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany); Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe (Germany)

    2015-03-30

    The pronounced temperature dependence of up-conversion luminescence from nanoparticles doped with rare-earth elements enables local temperature measurements. By mixing these nanoparticles into a commercially available photoresist containing the low-fluorescence photo-initiator Irgacure 369, and by using three-dimensional direct laser writing, we show that micrometer sized local temperature sensors can be positioned lithographically as desired. Positioning is possible in pre-structured environments, e.g., within buried microfluidic channels or on optical or electronic chips. We use the latter as an example and demonstrate the measurement for both free space and waveguide-coupled excitation and detection. For the free space setting, we achieve a temperature standard deviation of 0.5 K at a time resolution of 1 s.

  17. Three-dimensional micro-printing of temperature sensors based on up-conversion luminescence

    International Nuclear Information System (INIS)

    Wickberg, Andreas; Mueller, Jonathan B.; Mange, Yatin J.; Nann, Thomas; Fischer, Joachim; Wegener, Martin

    2015-01-01

    The pronounced temperature dependence of up-conversion luminescence from nanoparticles doped with rare-earth elements enables local temperature measurements. By mixing these nanoparticles into a commercially available photoresist containing the low-fluorescence photo-initiator Irgacure 369, and by using three-dimensional direct laser writing, we show that micrometer sized local temperature sensors can be positioned lithographically as desired. Positioning is possible in pre-structured environments, e.g., within buried microfluidic channels or on optical or electronic chips. We use the latter as an example and demonstrate the measurement for both free space and waveguide-coupled excitation and detection. For the free space setting, we achieve a temperature standard deviation of 0.5 K at a time resolution of 1 s

  18. Luminescence properties of uranyl-acetate species

    Energy Technology Data Exchange (ETDEWEB)

    Brinkmann, Hannes; Moll, Henry [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology; Stumpf, Thorsten [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biogeochemistry

    2017-06-01

    Time-resolved laser-induced fluorescence spectroscopy (TRLFS) was applied to characterize uranium(VI)- acetate species based on their luminescence properties. In contrast to previous interpretations, no indications were detected for the existence of the 1: 3 complex.

  19. 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.

  20. 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.

  1. Synthesis, crystal structure, theoretical study and luminescence ...

    Indian Academy of Sciences (India)

    and Material Engineering, Jiangnan University, Wuxi 214122, P. R. China. cChina-Australia Joint ... School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, P. R. China e-mail: ..... The title complex is luminescent.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Fabrication of highly luminescent InP/Cd and InP/CdS quantum dots

    International Nuclear Information System (INIS)

    Park, Jaehyun; Kim, Sunghoon; Kim, Sungwoo; Yu, Seung Tack; Lee, Bunyeoul; Kim, Sang-Wook

    2010-01-01

    Highly luminescent InP/Cd and InP/CdS core-shell QDs were fabricated by sequential addition of cadmium acetylacetonate and dodecanethiol to InP core solutions, which showed a red-shift in absorption and emission. ICP measurement revealed the existence of cadmium and TEM images showed the increased size of InP/CdS QDs. PXRD data identified zinc blend structures of InP and InP/CdS QDs, which indexed to the (1 1 1), (2 2 0) and (3 1 1) planes. The slight shift of peaks between InP and InP/CdS QDs can demonstrate the existence of CdS shell structures.

  7. Preheat-induced signal enhancement in the infrared stimulated luminescence of young and bleached sediment samples

    International Nuclear Information System (INIS)

    Richardson, C.A.

    2000-01-01

    Natural and laboratory bleached surface and young samples of potassium feldspar sand separates and polymineral silt had their infrared stimulated luminescence (IRSL) signal measured before and after preheating at 220 deg. C for 10 min or 160 deg. C for 16 h. For both preheats, the laboratory bleached sand samples underwent a signal enhancement which was stable with laboratory storage. The youngest samples also showed natural signal enhancement. The silt sample showed no recuperation of bleached signal on preheating, but some in the natural signal. A range of filtered bleaches was applied to one surface sand sample. Signal levels before and after preheating were reduced by filtering out the UV from the bleaching spectrum. The unfiltered bleach, however, most closely reproduced the behaviour of the natural sample

  8. 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

  9. MetR and CRP bind to the Vibrio harveyi lux promoters and regulate luminescence.

    Science.gov (United States)

    Chatterjee, Jaidip; Miyamoto, Carol M; Zouzoulas, Athina; Lang, B Franz; Skouris, Nicolas; Meighen, Edward A

    2002-10-01

    The induction of luminescence in Vibrio harveyi at the later stages of growth is controlled by a quorum-sensing mechanism in addition to nutritional signals. However, the mechanism of transmission of these signals directly to the lux promoters is unknown and only one regulatory protein, LuxR, has been shown to bind directly to lux promoter DNA. In this report, we have cloned and sequenced two genes, crp and metR, coding for the nutritional regulators, CRP (cAMP receptor protein) and MetR (a LysR homologue), involved in catabolite repression and methionine biosynthesis respectively. The metR gene was cloned based on a general strategy to detect lux DNA-binding proteins expressed from a genomic library, whereas the crp gene was cloned based on its complementation of an Escherichia coli crp mutant. Both CRP and MetR were shown to bind to lux promoter DNA, with CRP being dependent on the presence of cAMP. Expression studies indicated that the two regulators had opposite effects on luminescence: CRP was an activator and MetR a repressor. Disruption of crp decreased luminescence by about 1,000-fold showing that CRP is a major activator of luminescence the same as LuxR, whereas disruption of MetR resulted in activation of luminescence over 10-fold, confirming its function as a repressor. Comparison of the levels of the autoinducers involved in quorum sensing excreted by V. harveyi, and the crp and metR mutants, showed that autoinducer production was not significantly different, thus indicating that the nutritional signals do not affect luminescence by changing the levels of the signals required for quorum sensing. Indeed, the large effects of these nutritional sensors show that luminescence is controlled by multiple signals related to the environment and the cell density which must be integrated at the molecular level to control expression at the lux promoters.

  10. Hydrothermal synthesis, characterization, and luminescence of Ca_2B_2O_5:RE (RE = Eu"3"+, Tb"3"+, Dy"3"+) nanofibers

    International Nuclear Information System (INIS)

    Yang, Li; Wan, Yingpeng; Li, Yuze; Pu, Yinfu; Huang, Yanlin; Chen, Cuili; Seo, Hyo Jin

    2016-01-01

    Ca_2B_2O_5:RE (RE = Eu"3"+, Tb"3"+, Dy"3"+) nanofibers were synthesized by the hydrothermal reaction method. The structural refinement was conducted on the base of the X-ray powder diffraction (XRD) measurements. The surface properties of the Ca_2B_2O_5:RE (RE = Eu"3"+, Tb"3"+, Dy"3"+) nanofibers were investigated by the measurements such as the scanning electron microscope (SEM), transmission electron microscope (TEM), and the energy dispersive spectrum (EDS). The nanofiber has a diameter of about 100 nm and a length of several micrometers. The luminescence properties such as photoluminescence excitation (PLE) and emission spectra (PL), decay lifetime, color coordinates, and the absolute internal quantum efficiency (QE) were reported. Ca_2B_2O_5:Eu"3"+ nanofibers show the red luminescence with CIE coordinates of (x = 0.41, y = 0.51) and the luminescence lifetime of 0.63 ms. The luminescence of Ca_2B_2O_5:Tb"3"+ nanofibers is green color (x = 0.29, y = 0.53) with the lifetime of 2.13 ms. However, Dy"3"+-doped Ca_2B_2O_5 nanofibers present a single-phase white-color phosphor with the fluorescence decay of 3.05 ms. Upon near-UV excitation, the absolute quantum efficiency is measured to be 65, 35, and 37 % for Eu"3"+-, Tb"3"+-, Dy"3"+-doped Ca_2B_2O_5 nanofibers, respectively. It is suggested that Ca_2B_2O_5:RE (RE = Eu"3"+, Tb"3"+, Dy"3"+) nanofibers could be an efficient phosphor for lighting and display.

  11. 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

  12. Study of optically stimulated luminescence (OSL) for radiation detection. Application to an optical fibre {gamma}-radiation sensor; Etude de la luminescence stimulee optiquement (OSL) pour la detection de rayonnements: application a un capteur a fibre optique de rayonnement {gamma}

    Energy Technology Data Exchange (ETDEWEB)

    Roy, O. [CEA Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Electronique et d`Instrumentation Nucleaire]|[Paris-7 Univ., 75 (France)

    1998-12-31

    This work shows up the usefulness of the Optically Stimulated Luminescence (OSL) to resolve radioprotection problems. We study the use of OSL as a gamma dosimetric technique with respect to the ALARA`s concept (As Low As Reasonably Achievable). A new approach based on optical fibers and luminescent materials showing OSL properties (closely related to Thermoluminescence phenomena) is presented in order to improve the remote real time dosimetry monitoring. Like thermoluminescent materials (TLD), OSL materials can trap charges under an irradiation (UV, X, {gamma},...). Instead of heating, the charges trapped are released by light stimulation and produce a visible luminescence which amount is proportional to trap the `data stored` left by irradiation, enabling the dose measurement. The OSL phenomenon offers the same advantages as TLD plus the interesting possibility of a remote optical stimulation. The end-user objective deals with the development of a {gamma}-radiation Optical FIber Sensor (OFS) for dose measurement which can offer new functionalities based on OSL materials coupled with an optical fiber. Rare earth doped Alkaline Earth Sulphides (AES), BAFX:EU{sup 2+} (X = Cl, Br, I) and halogen alkaline have been studied (crystalline form, synthesis techniques, influence of dopants and color centers). Their characteristics are presented and extensively discussed. A specific experimental set-up to characterise various OSL phosphors has been developed. It allows the study of sensitivity, linearity, time decay behaviour of OSL signal and zeroing time. A joint study of OSL and TL has shown the technical limitations as well as the thermal fading and the origin of the long zeroing time. An Optical Fiber Sensor (OFS) based on OSL and using MgS:Sm has been developed for practical applications on nuclear fields. Its specifications are presented and discussed, moreover improvements are proposed. (author) 320 refs.

  13. 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.

  14. 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.

  15. 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.)

  16. 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.

  17. A human intervention study with foods containing natural Ah-receptor agonists does not significantly show AhR-mediated effects as measured in blood cells and urine.

    Science.gov (United States)

    de Waard, Pim W J; Peijnenburg, Ad A C M; Baykus, Hakan; Aarts, Jac M M J G; Hoogenboom, Ron L A P; van Schooten, Frederik J; de Kok, Theo M C M

    2008-10-22

    Binding and activation of the aryl hydrocarbon receptor (AhR) is thought to be an essential step in the toxicity of the environmental pollutants dioxins and dioxin-like PCBs. However, also a number of natural compounds, referred to as NAhRAs (natural Ah-receptor agonists), which are present in, for example, fruits and vegetables, can bind and activate this receptor. To study their potential effects in humans, we first investigated the effect of the prototypical AhR agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on gene expression in ex vivo exposed freshly isolated human lymphocytes, and compared the resulting gene expression profile with those caused by the well-known NAhRA indolo[3,2-b]carbazole (ICZ), originating from cruciferous vegetables, and by a hexane extract of NAhRA-containing grapefruit juice (GJE). Only ICZ induced a gene expression profile similar to TCDD in the lymphocytes, and both significantly up-regulated CYP1B1 and TIPARP (TCDD-inducible poly (ADP-ribose) polymerase) mRNA. Next, we performed a human intervention study with NAhRA-containing cruciferous vegetables and grapefruit juice. The expression of the prototypical AhR-responsive genes CYP1A1, CYP1B1 and NQO1 in whole blood cells and in freshly isolated lymphocytes was not significantly affected. Also enzyme activities of CYP1A2, CYP2A6, N-acetyltransferase 2 (NAT2) and xanthine oxidase (XO), as judged by caffeine metabolites in urine, were unaffected, except for a small down-regulation of NAT2 activity by grapefruit juice. Examination of blood plasma with DR CALUX showed a 12% increased AhR agonist activity 3 and 24 h after consumption of cruciferous vegetables, but did not show a significant effect of grapefruit juice consumption. We conclude that intake of NAhRAs from food may result in minor AhR-related effects measurable in human blood and urine.

  18. Study of optically stimulated luminescence (OSL) for radiation detection. Application to an optical fibre γ-radiation sensor

    International Nuclear Information System (INIS)

    Roy, O.

    1998-01-01

    This work shows up the usefulness of the Optically Stimulated Luminescence (OSL) to resolve radioprotection problems. We study the use of OSL as a gamma dosimetric technique with respect to the ALARA's concept (As Low As Reasonably Achievable). A new approach based on optical fibers and luminescent materials showing OSL properties (closely related to Thermoluminescence phenomena) is presented in order to improve the remote real time dosimetry monitoring. Like thermoluminescent materials (TLD), OSL materials can trap charges under an irradiation (UV, X, γ,...). Instead of heating, the charges trapped are released by light stimulation and produce a visible luminescence which amount is proportional to trap the 'data stored' left by irradiation, enabling the dose measurement. The OSL phenomenon offers the same advantages as TLD plus the interesting possibility of a remote optical stimulation. The end-user objective deals with the development of a γ-radiation Optical FIber Sensor (OFS) for dose measurement which can offer new functionalities based on OSL materials coupled with an optical fiber. Rare earth doped Alkaline Earth Sulphides (AES), BAFX:EU 2+ (X = Cl, Br, I) and halogen alkaline have been studied (crystalline form, synthesis techniques, influence of dopants and color centers). Their characteristics are presented and extensively discussed. A specific experimental set-up to characterise various OSL phosphors has been developed. It allows the study of sensitivity, linearity, time decay behaviour of OSL signal and zeroing time. A joint study of OSL and TL has shown the technical limitations as well as the thermal fading and the origin of the long zeroing time. An Optical Fiber Sensor (OFS) based on OSL and using MgS:Sm has been developed for practical applications on nuclear fields. Its specifications are presented and discussed, moreover improvements are proposed. (author)

  19. Luminescence and scintillation enhancement of Y{sub 2}O{sub 3}:Tm transparent ceramic through post-fabrication thermal processing

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, M.G.; Marchewka, M.R. [Department of Materials Science and Engineering, Clemson University, Clemson, SC 29634 (United States); Roberts, S.A.; Schmitt, J.M. [COMSET – Center for Optical Materials Science and Engineering Technologies, Clemson University, Anderson, SC 29625 (United States); McMillen, C. [Department of Chemistry, Clemson University, Clemson, SC 29634 (United States); Kucera, C.J. [COMSET – Center for Optical Materials Science and Engineering Technologies, Clemson University, Anderson, SC 29625 (United States); DeVol, T.A. [Environmental Engineering and Earth Sciences Department, Clemson University, Clemson, SC 29625 (United States); Ballato, J. [Department of Materials Science and Engineering, Clemson University, Clemson, SC 29634 (United States); COMSET – Center for Optical Materials Science and Engineering Technologies, Clemson University, Anderson, SC 29625 (United States); Jacobsohn, L.G., E-mail: luiz@clemson.edu [Department of Materials Science and Engineering, Clemson University, Clemson, SC 29634 (United States); COMSET – Center for Optical Materials Science and Engineering Technologies, Clemson University, Anderson, SC 29625 (United States)

    2015-09-15

    The effects of post-fabrication thermal processing in O{sub 2} flux on the luminescence and scintillation of a Y{sub 2}O{sub 3}:Tm transparent ceramic were investigated. The results showed that the strategy of post-fabrication processing can be beneficial to the performance of the ceramics, depending on the cumulative processing time. After the first hour of processing, about 40% enhancement in the luminescence output together with about 20% enhancement in the scintillation light yield were obtained. The enhancements were tentatively assigned to the incorporation of oxygen into vacancy sites. Longer cumulative processing times lead to the incorporation of oxygen as interstitials that is detrimental to scintillation light yield but not to luminescence output. This work also revealed that thermoluminescence measurements are a useful tool to predict scintillation light yield of Y{sub 2}O{sub 3}:Tm. - Highlights: • Scintillation and PL enhancement of transparent ceramics through thermal processing. • First thermoluminescence measurements of Y{sub 2}O{sub 3}:Tm above room temperature. • Observation of correlation between TL and scintillation light yield results.

  20. 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.

  1. Persistent luminescence and thermoluminescence of UV/VIS -irradiated SrAl2O4: Eu2+, Dy3+ phosphor

    International Nuclear Information System (INIS)

    Pereyda-Pierre, C.; Meléndrez, R.; García, R.; Pedroza-Montero, M.; Barboza-Flores, M.

    2011-01-01

    The persistent luminescence and thermoluminescence properties of SrAl 2 O 4 : Eu 2+ , Dy 3+ phosphors excited with UV–VIS light in the 200–500 nm region were investigated. The thermoluminescence glow curve was found to be composed of peaks around 70, 125 and 245 °C. The persistent luminescence and thermoluminescence excitation spectra exhibited a broad band around 300–500 nm centered at 400 and 420 nm respectively. A linear behavior of the integrated thermoluminescence intensity and persistent luminescence versus irradiation time was found for the first 60 s. The charge detrapping from the 70 °C trapping levels was the major contributor to the observed persistent luminescence at room temperature. The SrAl 2 O 4 : Eu 2+ , Dy 3+ phosphors have suitable properties to be applied as storage and persistent luminescence UV–VIS irradiation dose phosphor. -- Highlights: ► SrAl 2 O 4 :Eu 2+ , Dy 3+ persistent luminescence and thermoluminescence was measured. ► The phosphor was irradiated with UV–VIS photons in the 200–500 nm wavelength range. ► SrAl 2 O 4 :Eu 2+ , Dy 3+ behaves adequately as persistent and storage UV–VIS dosimeter. ► The persistent luminescence dosimetry does not require heat or light stimulation.

  2. Novel dental dynamic depth profilometric imaging using simultaneous frequency-domain infrared photothermal radiometry and laser luminescence

    Science.gov (United States)

    Nicolaides, Lena; Mandelis, Andreas

    2000-01-01

    A high-spatial-resolution dynamic experimental imaging setup, which can provide simultaneous measurements of laser- induced frequency-domain infrared photothermal radiometric and luminescence signals from defects in teeth, has been developed for the first time. The major findings of this work are: (1) radiometric images are complementary to (anticorrelated with) luminescence images, as a result of the nature of the two physical signal generation processes; (2) the radiometric amplitude exhibits much superior dynamic (signal resolution) range to luminescence in distinguishing between intact and cracked sub-surface structures in the enamel; (3) the radiometric signal (amplitude and phase) produces dental images with much better defect localization, delineation, and resolution; (4) radiometric images (amplitude and phase) at a fixed modulation frequency are depth profilometric, whereas luminescence images are not; and (5) luminescence frequency responses from enamel and hydroxyapatite exhibit two relaxation lifetimes, the longer of which (approximately ms) is common to all and is not sensitive to the defect state and overall quality of the enamel. Simultaneous radiometric and luminescence frequency scans for the purpose of depth profiling were performed and a quantitative theoretical two-lifetime rate model of dental luminescence was advanced.

  3. 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.

  4. Luminescent hybrid materials based on (8-hydroxyquinoline)-substituted metal-organic complexes and lead-borate glasses

    Science.gov (United States)

    Petrova, Olga B.; Anurova, Maria O.; Akkuzina, Alina A.; Saifutyarov, Rasim R.; Ermolaeva, Ekaterina V.; Avetisov, Roman I.; Khomyakov, Andrew V.; Taydakov, Ilya V.; Avetissov, Igor Ch.

    2017-07-01

    Novel luminescent organic-inorganic hybrid materials based on 8-hydroxyquinoline metal complexes (Liq, Kq, Naq, Rbq, Mgq2, Srq2, Znq2, Scq3, Alq3, Gaq3, and Inq3) have been synthesized by a high temperature exchange reaction with 80PbF2-20B2O3 inorganic low-melting glass. The mechanical and optical properties, transmission spectra, emission an excitation photoluminescence, and luminescence kinetic of hybrid materials were studied. All hybrid materials showed a wide luminescence band in the range 400-700 nm.

  5. Laser-excited luminescence of trace Nd3+ impurity in LaBr3 revealed by Raman spectroscopy

    Science.gov (United States)

    Yu, Jinqiu; Cui, Lei; He, Huaqiang; Hu, Yunsheng; Wu, Hao; Zeng, Jia; Liu, Yuzhu

    2012-10-01

    Unexpected additional bands with obvious non-vibrational features were observed in Raman spectra of LaBr3. Extensive study was carried out to reveal the origin of these bands. Results indicate that the additional bands correspond to laser-excited luminescence of trace Nd3+ impurity unintentionally introduced from the La2O3 raw material, which was further confirmed by Raman spectra of specially prepared Nd3+-doped LaBr3 and LaOBr samples. The luminescence properties of Nd3+ in different matrix were compared and discussed. The ultrasensitivity of Raman spectroscopy in detecting trace luminescent lanthanide ions shows good potential for analytical applications.

  6. Heavy metals detection using biosensor cells of a novel marine luminescent bacterium Vibrio sp. MM1 isolated from the Caspian Sea.

    Science.gov (United States)

    Mohseni, Mojtaba; Abbaszadeh, Jaber; Maghool, Shima-Sadat; Chaichi, Mohammad-Javad

    2018-02-01

    Monitoring and assessing toxic materials which are being released into the environment along with wastewater is a growing concern in many industries. The current research describes a highly sensitive and rapid method for the detection of toxic concentrations of heavy metals in aquatic environments. Water samples were collected from southern coasts of the Caspian Sea followed by screening of luminescent bacteria. Phylogenetic analysis, including gene sequence of 16S rRNA, and biochemical tests were performed for identification of the isolate. Luminescence activity was tested and measured after treatment of the isolate with different concentrations of heavy metals and reported as EC 50 value for each metal. A luminous, gram negative bacterium with the shape of a curved rod was isolated from the Caspian Sea. Biochemical tests and 16S rRNA gene sequence analysis indicated that the isolate MM1 had more than 99% similarity to Vibrio campbellii. The novel isolate is able to emit high levels of light. Bioluminescence inhibitory assay showed that the Vibrio sp. MM1 had the highest sensitivity to zinc and the lowest sensitivity to cadmium; EC 50 values were 0.97mgl -1 and 14.54mgl -1 , respectively. The current research shows that even low concentrations of heavy metals can cause a detectable decline in luminescence activity of the novel bacterium Vibrio sp. MM1; hence, it makes a good choice for commercial kits for the purpose of monitoring toxic materials. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. 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

  8. 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.

  9. The role of additives in the recombination luminescence mechanism of irradiated 2-methyltetrahydrofuran glasses

    International Nuclear Information System (INIS)

    Krauss, K.H.; Boes, J.

    1981-01-01

    The radiothermoluminescence (RTL) of γ-irradiated pure glassy 2-methyltetrahydrofuran (2-MTHF) and of 2-MTHF glasses containing additives was measured. For pure 2-MTHF a very weak luminescence peak at 93 K (heating rate 0,05 K/s) was found which in the presence of certain additives was enhanced by several orders of magnitude. Using data of radiothermoluminescence, absorption and phosphorescence measurements and bleaching experiments an attempt was made to derive a reaction mechanism. It was found to exist different possibilities for activation the ionic species to give recombination luminescence. (author)

  10. Luminescence studies of molecular materials

    International Nuclear Information System (INIS)

    Miller, P.F.

    2000-01-01

    Molecular materials have been widely studied for their potential uses in novel semiconductor devices. They occupy the intellectually interesting area between molecular and bulk descriptions of matter, and as such often have unique and useful characteristics. The design and engineering of these structures is inter-disciplinary in its nature, embracing the fields of physics, electrical engineering and both synthetic and physical chemistry. In this thesis luminescence studies of molecular materials will be presented that probe the nature of the excited states in two promising semiconductor systems. Luminescence techniques provide a powerful and sensitive tool in the investigation of kinetic pathways of radiative and non-radiative emission from these samples. This is particularly appropriate here, as the materials being studied are of potential use in electroluminescent devices. The suitability of photoluminescence techniques comes from both the electroluminescence and photoluminescence sharing the same emitting state. The first class of material studied here is an organic semiconducting polymer, cyano-substituted polyphenylenevinylene (CN-PPV). Conjugated polymers combine semiconducting electronic properties with favourable processing properties and offer the possibility of tuning their optical and electronic properties chemically. The cyanosubstitution increases the electron affinity of the polymer backbone, facilitating electron injection in light-emitting diodes. The polymers are soluble in solvents such as toluene and chloroform due the presence of alkoxy sidegroups. CdSe semiconductor nanocrystals are the other class of material characterised in this work. Semiconductor nanocrystals exhibit interesting size-tunable optical properties due to the confinement of the electronic wave functions. Characterisation of samples produced by different synthetic routes has been carried out to demonstrate the advantages of a novel synthetic method in terms of physical and

  11. Anodization of aluminium thin films on p{sup ++}Si and annihilation of strong luminescence from Al{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Efeoglu, Hasan, E-mail: hefeoglu@atauni.edu.t [Atatuerk University, Faculty of Engineering, Department of Electrical and Electronics Engineering, 25240 Erzurum (Turkey); Karacali, Tevhit [Atatuerk University, Faculty of Engineering, Department of Electrical and Electronics Engineering, 25240 Erzurum (Turkey); Meral, Kadem; Erdogan, Ibrahim Y.; Onganer, Yavuz [Atatuerk University, Faculty of Sciences, Department of Chemistry, 25240 Erzurum (Turkey)

    2010-01-15

    Photoluminescence (PL) of Al{sub 2}O{sub 3} films obtained by anodization of thermally evaporated and annealed thin Al films on p{sup ++}Si in 0.3 M oxalic acid has been investigated. Thermal annealing at 200-950 deg. C under the dry nitrogen atmosphere was used for deactivation of luminescence centres. Luminescence from as grown films was broad and located at 425 nm. This luminescence reached to highest level after annealing at 600 deg. C. Maximum 10 min was required for full optical activation and prolonged annealing up to 4 h did not change the luminescence intensity. Because of deep levels, absorption band edge of as grown films was shifted to the lower energy which is 3.25 eV. Annealing above 800 deg. C reduced the PL intensity and this observation was correlated with the blue shift of band edge as the defects annealed out. Disappearing PL intensity and blue shift of band edge absorption after annealing at 950 deg. C was mainly attributed to the oxygen-related defects and partly to impurities that may be originated from oxalic acid. AFM results did not show any hexagonally ordered holes but uniformly distributed nanosized Al{sub 2}O{sub 3} clusters that were clearly seen. XRD measurements on as grown Al{sub 2}O{sub 3} showed only [1 1 0] direction of alpha phase. Debye-Scherer calculation for this line indicates that cluster size is 35.7 nm. XRD and AFM pictures suggest that nanocrystalline Al{sub 2}O{sub 3} are embedded in amorphous Al{sub 2}O{sub 3}.

  12. 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

  13. Preparations and Characterizations of Luminescent Two Dimensional Organic-inorganic Perovskite Semiconductors

    Directory of Open Access Journals (Sweden)

    Sanjun Zhang

    2010-05-01

    Full Text Available This article reviews the synthesis, structural and optical characterizations of some novel luminescent two dimensional organic-inorganic perovskite (2DOIP semiconductors. These 2DOIP semiconductors show a self-assembled nano-layered structure, having the electronic structure of multi-quantum wells. 2DOIP thin layers and nanoparticles have been prepared through different methods. The structures of the 2DOIP semiconductors are characterized by atomic force microscopy and X-ray diffraction. The optical properties of theb DOIP semiconductors are characterized from absorption and photoluminescence spectra measured at room and low temperatures. Influences of different components, in particular the organic parts, on the structural and optical properties of the 2DOIP semiconductors are discussed.

  14. Optically stimulated luminescence dosimetry performance of natural Brazilian topaz exposed to beta radiation

    International Nuclear Information System (INIS)

    Bernal, R.; Souza, D. N.; Valerio, M. E. G.; Cruz-Vazquez, C.; Barboza-Flores, M.

    2006-01-01

    Optically stimulated luminescence (OSL) has become the technique of choice in many areas of dosimetry. Natural materials like topaz are available in large quantities in Brazil and other countries. They have been studied to investigate the possibility of use its thermoluminescence (TL) properties for dosimetric applications. In this work, we investigate the possibility of utilising the OSL properties of natural Brazilian topaz in dosimetry. Bulk topaz samples were exposed to doses up to 100 Gy of beta radiation and the integrated OSL as a function of the dose showed linear behaviour. The fading occurs in the first 20 min after irradiation but it is <6% of the integrated OSL measured shortly after exposure. We conclude that natural colourless topaz is a very suitable phosphor for OSL dosimetry. (authors)

  15. Synthesis of hydrophobic gold nanoclusters: growth mechanism study, luminescence property and catalytic application

    International Nuclear Information System (INIS)

    Selvam, Tamil Selvi; Chi, Kai-Ming

    2011-01-01

    One-pot synthesis of well dispersed, size-controlled gold nanoparticles with the average size of 10–15 nm and luminescent gold nanoclusters with average size of 1.7–2.0 nm were successfully achieved by thermal decomposition of gold organometallic precursor CH 3 AuPPh 3 in the presence of thiol surfactants in o-xylene. Only difference between the preparations of two types of Au nanoparticles is the amount of thiol surfactant employed. The mechanistic study of formation of gold nanoparticles was carried out by analyzing the samples at different reaction time intervals and revealed that two-staged growth process was involved. The nanoclusters showed strong red emission with the maximum intensity at about 600 nm. The maximum room temperature photoluminescence quantum yield was measured as 1.2%. The catalytic ability of the Au nanoclusters to promote Suzuki–Miyaura coupling involving the C–C bond formation was also investigated.

  16. Luminescence property of volcanic quartz and the use of red isothermal TL for dating tephras

    International Nuclear Information System (INIS)

    Tsukamoto, S.; Murray, A.S.; Huot, S.; Watanuki, T.; Denby, P.M.; Botter-Jensen, L.

    2007-01-01

    An optically stimulated luminescence (OSL) age obtained from a Japanese tephra using quartz phenocrysts severely underestimated the known age. The characteristics of the OSL signals were investigated in order to understand the cause of the underestimation; the main OSL component of volcanic quartz has a thermodynamic lifetime of about 1700 years at room temperature, and it also seems to fade anomalously (i.e. athermally). Measurement of conventional red thermoluminescence (RTL) using a Ga-As photomultiplier tube was difficult due to the presence of a strong thermal background, although RTL gave an age consistent with the independent age. Furthermore, red isothermal TL (RITL) at 380 deg. C allowed the RTL signal to be separated from to the thermal background, and RITL ages of three volcanic quartz samples show good agreement with independent ages

  17. Nonimaging optics in luminescent solar concentration.

    Science.gov (United States)

    Markman, B D; Ranade, R R; Giebink, N C

    2012-09-10

    Light trapped within luminescent solar concentrators (LSCs) is naturally limited in angular extent by the total internal reflection critical angle, θcrit, and hence the principles of nonimaging optics can be leveraged to increase LSC concentration ratio by appropriately reshaping the edges. Here, we use rigorous ray-tracing simulations to explore the potential of this concept for realistic LSCs with compound parabolic concentrator (CPC)-tapered edges and show that, when applied to a single edge, the concentration ratio is increased by 23% while maintaining >90% of the original LSC optical efficiency. Importantly, we find that CPC-tapering all of the edges enables a significantly greater intensity enhancement up to 35% at >90% of the original optical efficiency, effectively enabling two-dimensional concentration through a cooperative, ray-recycling effect in which rays rejected by one CPC are accepted by another. These results open up a significant opportunity to improve LSC performance at virtually no added manufacturing cost by incorporating nonimaging optics into their design.

  18. Magnetic nanosensor particles in luminescence upconversion capability.

    Science.gov (United States)

    Wilhelm, Stefan; Hirsch, Thomas; Scheucher, Elisabeth; Mayr, Torsten; Wolfbeis, Otto S

    2011-09-05

    Nanoparticles (NPs) exhibit interesting size-dependent electrical, optical, magnetic, and chemical properties that cannot be observed in their bulk counterparts. The synthesis of NPs (i.e., crystalline particles ranging in size from 1 to 100 nm) has been intensely studied in the past decades. Magnetic nanoparticles (MNPs) form a particularly attractive class of NPs and have found numerous applications such as in magnetic resonance imaging to visualize cancer, cardiovascular, neurological and other diseases. Other uses include drug targeting, tissue imaging, magnetic immobilization, hyperthermia, and magnetic resonance imaging. MNPs, due to their magnetic properties, can be easily separated from (often complex) matrices and manipulated by applying external magnetic field. Near-infrared to visible upconversion luminescent nanoparticles (UCLNPs) form another type of unusual nanoparticles. They are capable of emitting visible light upon NIR light excitation. Lanthanide-doped (Yb, Er) hexagonal NaYF₄ UCLNPs are the most efficient upconversion phosphors known up to now. The use of UCLNPs for in vitro imaging of cancer cells and in vivo imaging in tissues has been demonstrated. UCLNPs show great potential as a new class of luminophores for biological, biomedical, and sensor applications. We are reporting here on our first results on the combination of MNP and UCLNP technology within an ongoing project supported by the DFG and the FWF (Austria).

  19. Luminescence dating of the PASADO core 5022-1D from Laguna Potrok Aike (Argentina) using IRSL signals from feldspar

    DEFF Research Database (Denmark)

    Buylaert, Jan-Pieter; Murray, A.S.; Gebhardt, A.C.

    2013-01-01

    We have measured and tested a luminescence chronology for the PASADO core 5022-1D from the maar lake of Laguna Potrok Aike. Because of unsuitable quartz OSL characteristics, sand-sized K-feldspar extracts were chosen as a dosimeter and the dose was measured using a post-IR IRSL (pIRIR290......) measurement protocol. Using this approach we were able to access a stable signal and thus avoid the ubiquitous problem of feldspar signal instability. Extensive laboratory tests show that the chosen pIRIR290 protocol is applicable to these samples. We also developed a new criterion based on known relative...... or stratigraphy; the resulting age–depth profile is self-consistent, increases smoothly with depth and is in agreement with independent age control based on volcanic ash layers (Reclús, Mt Burney and Hudson tephras) at the top and middle of the core. Our new luminescence chronology suggests that the 5022-1D core...

  20. 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...

  1. Label free luminescence strategy for sensitive detection of ATP using aptamer-Ru(II) complexes

    Energy Technology Data Exchange (ETDEWEB)

    Babu, Eththilu [Department of Physical Che mistry, School of Chemistry, Madurai Kamaraj University, Madurai 625021, Tamil Nadu (India); Muthu Mareeswaran, Paulpandian [Department of Physical Che mistry, School of Chemistry, Madurai Kamaraj University, Madurai 625021, Tamil Nadu (India); Department of Industrial Chemistry, Alagappa Univesity, Karaikudi 630003, Tamil Nadu (India); Ramdass, Arumugam [Department of Physical Che mistry, School of Chemistry, Madurai Kamaraj University, Madurai 625021, Tamil Nadu (India); Research Department of Chemistry, Aditanar College of Arts and Science, Tiruchendur 628216, Tamil Nadu (India); Ramesh, Pandian [UCIBIO-REQUIMTE, Departmento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica (Portugal); Rajagopal, Seenivasan, E-mail: rajagopalseenivasan@yahoo.com [Department of Physical Che mistry, School of Chemistry, Madurai Kamaraj University, Madurai 625021, Tamil Nadu (India)

    2016-07-15

    A simple and sensitive aptamer-based luminescence strategy for ATP detection is developed using Ru(II) complexes as probe molecule. It is based on the fact that Ru(II)-dppz complexes show the light switching behavior with DNA aptamers and found to show significant luminescence spectral change on the addition of ATP molecules. The binding efficiencies of aptamer with ATP, ADP and AMP are calculated and compared. The structural change of aptamer is also studied using circular dichroism (CD) spectral techniques. Moreover, the binding nature of aptamer with ATP, ADP and AMP is demonstrated by computational techniques. The proposed strategy was successfully applied to the detection of ATP.

  2. Label free luminescence strategy for sensitive detection of ATP using aptamer-Ru(II) complexes

    International Nuclear Information System (INIS)

    Babu, Eththilu; Muthu Mareeswaran, Paulpandian; Ramdass, Arumugam; Ramesh, Pandian; Rajagopal, Seenivasan

    2016-01-01

    A simple and sensitive aptamer-based luminescence strategy for ATP detection is developed using Ru(II) complexes as probe molecule. It is based on the fact that Ru(II)-dppz complexes show the light switching behavior with DNA aptamers and found to show significant luminescence spectral change on the addition of ATP molecules. The binding efficiencies of aptamer with ATP, ADP and AMP are calculated and compared. The structural change of aptamer is also studied using circular dichroism (CD) spectral techniques. Moreover, the binding nature of aptamer with ATP, ADP and AMP is demonstrated by computational techniques. The proposed strategy was successfully applied to the detection of ATP.

  3. 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

  4. 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

  5. Spectral study of the luminescence produced by the excitation of noble gases by alpha-rays; Etude spectrale de la luminescence due a l'excitation des gaz rares par les rayons alpha

    Energy Technology Data Exchange (ETDEWEB)

    Koch, L [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    Luminescence spectra of the noble gases He, A, Kr and Xe are studied under excitation by {alpha} rays. It is shown that the energy is transferred from excited levels of these gases to Hg and N{sub 2} impurities for impurity concentrations respectively less than 10{sup 6} and 10{sup 4}. These results confirm previous measurements concerning the period of luminescence and its variations versus nitrogen concentration in noble gases. (author) [French] On etudie les spectres de luminescence des gaz rares, He, A, Kr et Xe excites par une source intense de rayons {alpha}. Le transfert d'energie des etats excites des gaz rares sur les impuretes mercure et azote pour des concentrations respectives de ces impuretes inferieures a 1 ppm et 100 ppm est demontre. Ces resultats confirment les mesures anterieures concernant la duree de luminescence et ses variations avec la concentration d'azote dans les gaz rares. (auteur)

  6. 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

  7. Long-term measurement of anti-adalimumab using pH-shift-anti-idiotype antigen binding test shows predictive value and transient antibody formation

    NARCIS (Netherlands)

    van Schouwenburg, Pauline A.; Krieckaert, Charlotte L.; Rispens, Theo; Aarden, Lucien; Wolbink, Gerrit Jan; Wouters, Diana

    2013-01-01

    Therapeutic monoclonal antibodies are effective drugs for many different diseases. However, the formation of anti-drug antibodies (ADA) against a biological can result in reduced clinical response in some patients. Measurement of ADA in the presence of (high) drug levels is difficult due to drug

  8. 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)

  9. 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)

  10. Structural and luminescence properties of Mn2+ ions doped calcium zinc borophosphate glasses

    International Nuclear Information System (INIS)

    Wan, Ming Hua; Wong, Poh Sum; Hussin, Rosli; Lintang, Hendrik O.; Endud, Salasiah

    2014-01-01

    Highlights: • FT-IR revealed that the network structures are from borate and phosphate network. • The PL spectrum exhibits a green emission band at 582 nm ( 4 T 1g → 6 A 1g ). • As the concentration of Mn 2+ ions is increased, the emission band had been red shifted. • These glasses are found to have potential applications as luminescent optical materials. - Abstract: Calcium zinc borophosphate glasses (CaZnBP) doped with various concentrations of Mn 2+ ions and borate and phosphate as variable were prepared using conventional melt quenching technique. The structure of obtained glasses were examined by means of use: X-ray diffraction (XRD) and fourier transform infrared (FT-IR). XRD analysis confirmed amorphous nature of glass samples. The FT-IR spectra reveals the presence of both borate and phosphate vibrational modes in the prepared glasses. The doping of Mn 2+ ions (2–10 mol%) shows no significant changes in the main IR vibrational bands. Optical properties were studied by measuring the near infrared photoluminescence (PL) spectra. CaZnBP glasses exhibited intense green emission peak (582 nm) (tetrahedral symmetry), which is assigned to a transition from the upper 4 T 1g → 6 A 1g ground state of Mn 2+ ions. As the concentration of Mn 2+ ions increases, the emission band increases from 582 nm to 650 nm and exhibited a red light emission (octahedral symmetry). The decay curves of 4 T 1g level were examined for all concentrations and the measured lifetimes are found to depend strongly on Mn 2+ concentrations. From the emission characteristic parameters of 6 A 1g (S) level, it shows that the CaZnBP glasses could have potential applications as luminescent optical materials, visible lasers and fluorescent display devices

  11. Ag2O dependent up-conversion luminescence properties in Tm3+/Er3+/Yb3+ co-doped oxyfluorogermanate glasses

    International Nuclear Information System (INIS)

    Hu, Yuebo; Qiu, Jianbei; Song, Zhiguo; Zhou, Dacheng

    2014-01-01

    Up-conversion (UC) luminescence properties of Ag/Tm 3+ /Er 3+ /Yb 3+ co-doped oxyfluorogermanate glasses have been studied to assess the effective role of silver nanoparticles as a sensitizer for Tm 3+ and Er 3+ ions. The X-ray diffraction patterns obtained in this work do not reveal any crystalline phase in the glass. However, the absorption spectra reveal that surface plasmons resonance band of Ag undergoes a distinct split with two maxima and a very broad absorption peak with a background that extends toward the near infrared (NIR) with the increasing of Ag 2 O added concentration. Transmission electron microscope images confirm that silver nanoparticles have been precipitated from matrix glasses and show their distribution, size, and shapes. In addition, changes in UC luminescence intensity of four emission bands 476, 524, 546, and 658 nm corresponding to 1 G 4 → 3 H 6 (Tm 3+ ), ( 2 H 11/2 , 4 S 3/2 ) → 4 I 15/2 (Er 3+ ), and 4 F 9/2 → 4 I 15/2 (Er 3+ ) transitions, respectively, as a function of silver addition to the base composition have been measured under 980 nm excitation. It is confirmed that Ag 2 O added concentration plays an important role in increasing the UC luminescence intensity; however, further increase in Ag 2 O added concentration reduces the intensity

  12. Structural, luminescence and biological studies of trivalent lanthanide complexes with N,N Prime -bis(2-hydroxynaphthylmethylidene)-1,3-propanediamine Schiff base ligand

    Energy Technology Data Exchange (ETDEWEB)

    Taha, Ziyad A., E-mail: tahaz33@just.edu.jo [Department of Applied Chemistry, Faculty of Arts and Sciences, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110 (Jordan); Ajlouni, Abdulaziz M. [Department of Applied Chemistry, Faculty of Arts and Sciences, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110 (Jordan); Al Momani, Waleed [Department of Allied Medical Sciences, Al Balqa Applied University (Jordan)

    2012-11-15

    New eight lanthanide metal complexes were prepared. These complexes were characterized by elemental analysis, molar conductivity measurements, spectral analysis ({sup 1}H NMR, FT-IR, UV-vis), luminescence and thermal gravimetric analysis. All Ln(III) complexes were 1:1 electrolytes as established by their molar conductivities. The microanalysis and spectroscopic analysis revealed eight-coordinated environments around lanthanide ions with two nitrate ligands behaving in a bidentate manner. The other four positions were found to be occupied with tetradentate L{sub III} ligand. Tb-L{sub III} and Sm-L{sub III} complexes exhibited characteristic luminescence emissions of the central metal ions and this was attributed to efficient energy transfer from the ligand to the metal center. The L{sub III} and Ln-L{sub III} complexes showed antibacterial activity against a number of pathogenic bacteria. - Highlights: Black-Right-Pointing-Pointer Ln(III) ion adopts an eight-coordinate geometry. Black-Right-Pointing-Pointer Luminescence spectra of Sm-L{sub III} and Tb-L{sub III} complexes display the metal centered line emission. Black-Right-Pointing-Pointer Energy transfer process from L{sub III} to Sm in Sm-L{sub III} complex is more efficient than to Tb in Tb-L{sub III} complex. Black-Right-Pointing-Pointer Ln(III) complexes may serve as models for biologically important species.

  13. Piezoelectric and deformation potential effects of strain-dependent luminescence in semiconductor quantum well structures

    DEFF Research Database (Denmark)

    Zhang, Aihua; Peng, Mingzeng; Willatzen, Morten

    2017-01-01

    The mechanism of strain-dependent luminescence is important for the rational design of pressure-sensing devices. The interband momentum-matrix element is the key quantity for understanding luminescent phenomena. We analytically solved an infinite quantum well (IQW) model with strain, in the frame......The mechanism of strain-dependent luminescence is important for the rational design of pressure-sensing devices. The interband momentum-matrix element is the key quantity for understanding luminescent phenomena. We analytically solved an infinite quantum well (IQW) model with strain......, in the framework of the 6 × 6 k·p Hamiltonian for the valence states, to directly assess the interplay between the spin-orbit coupling and the strain-induced deformation potential for the interband momentum-matrix element. We numerically addressed problems of both the infinite and IQWs with piezoelectric fields...... to elucidate the effects of the piezoelectric potential and the deformation potential on the strain-dependent luminescence. The experimentally measured photoluminescence variatio½n as a function of pressure can be qualitatively explained by the theoretical results....

  14. 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.

  15. Can glacial shearing of sediment reset the signal used for luminescence dating?

    Science.gov (United States)

    Bateman, Mark D.; Swift, Darrel A.; Piotrowski, Jan A.; Rhodes, Edward J.; Damsgaard, Anders

    2018-04-01

    Understanding the geomorphology left by waxing and waning of former glaciers and ice sheets during the late Quaternary has been the focus of much research. This has been hampered by the difficulty in dating such features. Luminescence has the potential to be applied to glacial sediments but requires signal resetting prior to burial in order to provide accurate ages. This paper explores the possibility that, rather than relying on light to reset the luminescence signal, glacial processes underneath ice might cause resetting. Experiments were conducted on a ring-shear machine set up to replicate subglacial conditions and simulate the shearing that can occur within subglacial sediments. Luminescence measurement at the single grain level indicates that a number (albeit small) of zero-dosed grains were produced and that these increased in abundance with distance travelled within the shearing zone. Observed changes in grain shape characteristics with increasing shear distance indicate the presence of localised high pressure grain-to-grain stresses caused by grain bridges. This appears to explain why some grains became zeroed whilst others retained their palaeodose. Based on the observed experimental trend, it is thought that localised grain stress is a viable luminescence resetting mechanism. As such relatively short shearing distances might be sufficient to reset a small proportion of the luminescence signal within subglacial sediments. Dating of previously avoided subglacial sediments may therefore be possible.

  16. Optically stimulated luminescence techniques in retrospective dosimetry using single grains of quartz extracted from unheated materials

    Energy Technology Data Exchange (ETDEWEB)

    Joerkov Thomsen, Kristina

    2004-02-01

    This work investigates the possibility of applying optically stimulated luminescence (OSL) in retrospective dose determinations using unheated materials. It focuses on identifying materials suitable for use in assessment of doses absorbed as a consequence of radiation accidents (i.e. accident dosimetry). Special attention has been paid to quartz extracted from unheated building materials such as concrete and mortar. The single-aliquot regeneration-dose (SAR) protocol has been used to determine absorbed doses in small aliquots as well as single grains of quartz. It is shown that OSL measurements of single grains of quartz extracted from poorly-bleached building materials can provide useful information on radiation accident doses, even when the luminescence sensitivity is low. Sources of variance in well-bleached single grain dose distributions have been investigated in detail and it is concluded that the observed variability in the data is consistent with the sum (in quadrature) of a component, which depends on the number of photons detected from each grain, and a fixed component independent of light level. Dose depth profiles through laboratory irradiated concrete bricks have successfully been measured and minimum detection limits of less than 100 mGy are derived. Measurements of thermal transfer in single grains of poorly-bleached quartz show that thermal transfer is variable on a grain-to-grain basis and that it can be a source of variance in single-grain dose distributions. Furthermore, the potential of using common household and workplace chemicals, such as table salt, washing powder and water softener, in retrospective dosimetry has been investigated. It is concluded that such materials should be considered as retrospective dosimeters in the event of a radiation accident. (au)

  17. STM-excited luminescence of porous and spark-processed silicon

    International Nuclear Information System (INIS)

    Andrienko, I.; Kuznetsov, V.; Yuan, J.; Haneman, D.

    1998-01-01

    Full text: Scanning tunneling microscopy (STM) permits highly local electronic excitation of light emission (LE) from the surface of silicon. Measuring STM LE, one can study simultaneously both the topography and the luminescence properties of areas down to nm dimensions and thus make conclusions about the luminescence mechanism of the material. We have built an STM spectroscopy system which allows measurement of spectra of visible light emitted from areas as small as 13 x 13 nm 2 (porous silicon) and 10 x 10 nm 2 (spark-processed silicon). Porous silicon shows a broad emission band centered at 630 nm, and spark-processed silicon, one at 690 nm. The STM LE spectra of spark-processed silicon obtained for the first time. We have found that visible light is emitted only from areas containing nanometer-scale structures down to around 2 nm in diameter. STM LE occurs under negative bias voltage applied to the tip, i.e. when electrons are injected into the sample. Other workers used p-type silicon for the sample preparations, but it has been found that STM LE can be induced also from n-type silicon. Furthermore, we have shown that STM LE spectra can be resolved using much lover voltages and tunneling currents: -(7-9) V and 25 - 50 nA vs -(25-50) V and 100 nA. To consider different excitation mechanisms, the STM LE measurements are compared with photoluminescence and electroluminescence spectra of similar samples. We suggest that excitation of individual quantum confinement structures has been observed

  18. Use of a novel cell adhesion method and digital measurement to show stimulus-dependent variation in somatic and oral ciliary beat frequency in Paramecium.

    Science.gov (United States)

    Bell, Wade E; Hallworth, Richard; Wyatt, Todd A; Sisson, Joseph H

    2015-01-01

    When Paramecium encounters positive stimuli, the membrane hyperpolarizes and ciliary beat frequency increases. We adapted an established immobilization protocol using a biological adhesive and a novel digital analysis system to quantify beat frequency in immobilized Paramecium. Cells showed low mortality and demonstrated beat frequencies consistent with previous studies. Chemoattractant molecules, reduction in external potassium, and posterior stimulation all increased somatic beat frequency. In all cases, the oral groove cilia maintained a higher beat frequency than mid-body cilia, but only oral cilia from cells stimulated with chemoattactants showed an increase from basal levels. © 2014 The Author(s) Journal of Eukaryotic Microbiology © 2014 International Society of Protistologists.

  19. Directly measured free 25-hydroxy vitamin D levels show no evidence of vitamin D deficiency in young Swedish women with anorexia nervosa.

    Science.gov (United States)

    Carlsson, Martin; Brudin, Lars; Wanby, Pär

    2018-04-01

    Anorexia nervosa (AN) is an eating disorder characterized by low fat mass complicated by osteoporosis. The role of circulating vitamin D in the development of bone loss in AN is unclear. Fat mass is known to be inversely associated with vitamin D levels measured as serum levels of total, protein-bound 25-hydroxyvitamin D, but the importance of directly measured, free levels of 25(OH)D has not been determined in AN. The aim of this study was to investigate vitamin D status, as assessed by serum concentrations of total and free serum 25(OH)D in patients with AN and healthy controls. In female AN patients (n = 20), and healthy female controls (n = 78), total 25(OH)D was measured by LC-MS/MS, and free 25(OH)D with ELISA. In patients with AN bone mineral density (BMD) was determined with DEXA. There were no differences between patients and controls in total or free S-25(OH)D levels (80 ± 31 vs 72 ± 18 nmol/L, and 6.5 ± 2.5 vs 5.6 ± 1.8 pg/ml, respectively), and no association to BMD was found. In the entire group of patients and controls, both vitamin D parameters correlated with BMI, leptin, and PTH. The current study did not demonstrate a vitamin D deficiency in patients with AN and our data does not support vitamin D deficiency as a contributing factor to bone loss in AN. Instead, we observed a trend toward higher vitamin D levels in AN subjects compared to controls. Measurement of free vitamin D levels did not contribute to additional information.

  20. Efficient tunable luminescence of SiGe alloy sheet polymers

    International Nuclear Information System (INIS)

    Vogg, G.; Meyer, A. J.-P.; Miesner, C.; Brandt, M. S.; Stutzmann, M.

    2001-01-01

    Crystalline SiGe alloy sheet polymers were topotactically prepared from epitaxially grown calcium germanosilicide Ca(Si 1-x Ge x ) 2 precursor films in the whole composition range. These polygermanosilynes are found to be a well-defined mixture of the known siloxene and polygermyne sheet polymers with the OH groups exclusively bonded to silicon. The optical properties determined by photoluminescence and optical reflection measurements identify the mixed SiGe sheet polymers as direct semiconductors with efficient luminescence tunable in the energy range between 2.4 and 1.3 eV. [copyright] 2001 American Institute of Physics

  1. Detection of Irradiated Food using Photostimulated Luminescence (PSL) Technique

    International Nuclear Information System (INIS)

    Foziah Ali; Ros Anita Ahmad Ramli; Zainab Harun; Zainon Othman

    2015-01-01

    The Photostimulated luminescence (PSL) method may in principles be applied to detect irradiation of any foods which contain mineral debris, especially silicates mineral and bio inorganic materials such as calcite, which originate from shells or skeleton. These materials store energy in charge carriers trapped at structural interstitial or impurities site. When exposed to ionizing radiation optical stimulation of minerals release charges carriers. In PSL measurements, whole samples or a mixture of organic and inorganic materials can be used. The finding of this study will be useful to facilitate control of food irradiation application in Malaysia. (author)

  2. 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)

  3. Highly visible-light luminescence properties of the carboxyl-functionalized short and ultrashort MWNTs

    International Nuclear Information System (INIS)

    Luo Yongsong; Xia Xiaohong; Liang Ying; Zhang Yonggang; Ren Qinfeng; Li Jialin; Jia Zhijie; Tang Yiwen

    2007-01-01

    Luminescence of the short multiwalled carbon nanotubes (MWNTs) conjugated with carboxylic acid groups has been studied. The results show that the carboxyl-functionalized short MWNTs could emit luminescence and the emission peak appears at 500 nm with a corresponding optimal excitation wavelength centering at 310 nm. When the short MWNTs are filtered through 0.15 μm polytetrafluoroethylene (PTFE) membrane, the ultrashort MWNTs are obtained from the filtrate. An interesting feature for the ultrashort MWNTs is that the emission intensity is strengthened and the peak is slightly blue shifted to 460 nm. This result indicates that the luminescence properties of MWNTs are strongly affected by the tube length. After chemical oxidization cutting, defects and carboxylic acid groups at the tube end and/or sidewall can be produced; the more shorten of MWNTs, the better dispersion and carboxylic passivation of the nanotubes, and the more intense luminescence emissions. The broad emissions are logically attributed to the trapping of excitation energy by defect sites in the carboxyl-functionalized nanotube structure. - Graphical abstract: Luminescence of the short and ultrashort multiwalled carbon nanotubes (MWNTs) conjugated with carboxylic acid groups, which is logically attributed to the trapping of excitation energy by defect sites, has been studied

  4. Investigation of electro-optical properties for electrochemical luminescence device with a new electrode structure

    Science.gov (United States)

    Ok, Jung-Woo; Pooyodying, Pattarapon; Anuntahirunrat, Jirapat; Sung, Youl-Moon

    2018-04-01

    In this paper, we investigate electrochemical luminescent (ECL) device with a new structure and the ECL cell device with proposed electrode configuration works reliably at AC voltage. In particular, the conventional ECL cell has counter electrodes in which a cathode and an anode are opposed to each other, whereas the proposed structure has parallel electrodes in which a cathode and an anode are arranged on a single substrate. The proposed electrode configuration has a structural feature that electric short-circuiting is less likely to occur during bending than the conventional electrode configuration. The electro-optical characteristics of the new electrode configuration such as the current density, the light emission intensity, and the time evolution of the emission are investigated. The proposed ECL device exhibited higher light emitting efficiency than the conventional structure. Especially, at AC operation mode, the new structure showed the distinctive luminescence characteristic which is combined the first luminescence near the surface of electrode with the delayed second luminescence near the center of between electrodes. It was closely related to the behavior of luminescent particles. The proposed the ECL cell structure is expected to be utilized as a flexible display device by taking advantage of its characteristics and practicality.

  5. Crack luminescence as an innovative method for detection of fatigue damage

    Directory of Open Access Journals (Sweden)

    R. Makris

    2018-04-01

    Full Text Available Conventional non-destructive testing methods for crack detection provide just a snapshot of fatigue crack evolution at a specific location in the moment of examination. The crack luminescence coating realizes a clear visibility of the entire crack formation. The coating consists of two layers with different properties and functions. The bottom layer emits light as fluorescence under UV radiation. The top layer covers the fluorescing one and prevents the emitting of light in case of no damage at the surface. Several different experiments show that due to the sensitive coating even the early stage of crack formation can be detected. That makes crack luminescence helpful for investigating the incipient crack opening behavior. Cracks can be detected and observed during operation of a structure, making it also very interesting for continuous monitoring. Crack luminescence is a passive method and no skilled professionals are necessary to detect cracks, as for conventional methods. The luminescent light is clearly noticeable by unaided eye observations and also by standard camera equipment, which makes automated crack detection possible as well. It is expected that crack luminescence can reduce costs and time for preventive maintenance and inspection.

  6. [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.

  7. 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

  8. 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

  9. Radiation-induced luminescence from dry and hydrated DNA and related macromolecules

    International Nuclear Information System (INIS)

    Al-Kazwini, A.T.; O'Neill, P.; Fielden, E.M.; Adams, G.E.

    1988-01-01

    The radiation-induced luminescence from three types of fibrous DNA and a series of polydeoxynucleotides was measured under vacuum or in the presence of oxygen at 77 and 293K. The in-pulse emission spectra, generated by electrons with energies 50% water by wt (1.2:1 w/w, H 2 O/DNA), the in-pulse luminescence spectrum is similar to that of dry DNA. These findings are discussed in terms of energy or charge migration induced in DNA upon irradiation and the possible effects of conformational changes, caused by hydration, on charge migration. (author)

  10. Stimulation of mineral-specific luminescence from multi-mineral samples

    DEFF Research Database (Denmark)

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

    1995-01-01

    Grains of quartz and potassium-rich feldspar have been mixed in known ratios to produce samples of known mineralogical composition, analogous to those found in natural sedimentary deposits. The variation of the green light stimulated luminescence (GLSL), as a function of sample temperature......, was measured for each of these mixtures in order to attempt to isolate a luminescence signal that originates specifically from just one of the components. As the sample is heated from room temperature to 450 degrees C, thermal quenching reduces the signal from the quartz component to near zero, while that from...... geological samples....

  11. 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.

  12. Single fiber temperature probe configuration using anti-Stokes luminescence from Cr:GdAlO3

    Science.gov (United States)

    Eldridge, Jeffrey I.

    2018-06-01

    Single-photon excitation of anti-Stokes-shifted emission from a thermographic phosphor allows operation of a luminescence decay-based single fiber temperature probe with negligible interference from background fiber-generated Raman scattering. While single fiber probe configurations for luminescence-based fiber optic thermometers offer advantages of simple design, compactness, and superior emission light collection efficiency, their effective use has been limited by interference from Raman scattering in the fiber probe and excitation delivery fiber that produces distortion of the luminescence decay that follows the excitation pulse. The near elimination of interference by background fiber-generated Raman scattering was demonstrated by incorporating a Cr-doped GdAlO3 (Cr:GdAlO3) thermographic phosphor as the sensing element at the end of a single fiber luminescence decay-based thermometer and detecting anti-Stokes-shifted luminescence centered at 542 or 593 nm produced by 695 nm excitation. Measurements were performed using both silica (up to 1150 °C) and single-crystal YAG (up to 1200 °C) fiber-based thermometers. Selection of emission detection centered at 542 nm greatly benefited the YAG fiber probe measurements by practically eliminating detection of otherwise significant luminescence from Cr3+ impurities in the YAG fiber. For both the silica and YAG fiber probes, the relative benefit of adopting single-photon excitation of anti-Stokes-shifted luminescence was evaluated by comparison with results obtained by conventional 532 nm excitation of Stokes-shifted luminescence.

  13. Ion beam induced luminescence: Relevance to radiation induced bystander effects

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, S.B., E-mail: ahmad.rabilal@gmail.com [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); McNeill, F.E., E-mail: fmcneill@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Byun, S.H., E-mail: soohyun@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Prestwich, W.V., E-mail: prestwic@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Seymour, C., E-mail: seymouc@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Mothersill, C.E., E-mail: mothers@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada)

    2012-10-01

    The aim of this work is quantify the light emitted as a result of charged particle interaction in materials which may be of relevance to radiation induced 'bystander effects' studies. We have developed a system which employs single photon counting to measure the light emitted from samples irradiated under vacuum by a charged particle beam. The system uses a fast photomultiplier tube with a peak cathode response at 420 nm. It has been tested in a proof-of-principle experiment using polystyrene targets. Light output, as a result of irradiation, was measured. The luminescence yield appears to have a non-linear behavior with the incident ion fluence: it rises exponentially to an asymptotic value. The target was irradiated with beam energies varying from 1 to 2 MeV and showed saturation at or before an incident fluence rate of 3 Multiplication-Sign 10{sup 13} H{sup +}/cm{sup 2} s. The average saturation value for the photon output was found to be 40 Multiplication-Sign 10{sup 6} cps. Some measurements were performed using filters to study the emission at specific wavelengths. In the case of filtered light measurements, the photon output was found to saturate at 28 Multiplication-Sign 10{sup 3}, 10 Multiplication-Sign 10{sup 6}, and 35 Multiplication-Sign 10{sup 6} cps for wavelengths of 280 {+-} 5 nm, 320 {+-} 5 nm and 340 {+-} 5 nm respectively. The light output reaches a maximum value because of damage induced in the polymer. Our measurements indicate a 'damage cross section' of the order of 10{sup -14} cm{sup 2}. The average radiant intensity was found to increase at wavelengths of 280 and 320 nm when the proton energy was increased. This was not found to occur at 340 nm. In conclusion, the light emission at specific wavelengths was found to depend upon the incident proton fluence and the proton energy. The wavelengths of the emitted light measured in this study have significance for the understanding of radiation induced bystander effects.

  14. 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.

  15. 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

  16. Luminescence properties of glaciofluvial sediments from the Bavarian Alpine Foreland

    International Nuclear Information System (INIS)

    Klasen, N.; Fiebig, M.; Preusser, F.; Radtke, U.

    2006-01-01

    Dose recovery tests highlight the variation of luminescence properties for samples from different sites and sediment sources within a region. It is hence necessary to adjust parameters of the single-aliquot regenerative dose protocol for different samples to ensure complete dose recovery. Bleaching experiments demonstrate an initially faster bleaching of the quartz optical signal compared to feldspar. However, complete resetting of the optical signal of both quartz and feldspar minerals occurred within approximately the same time. Moreover, samples from different sites show significant differences in bleaching characteristics. Investigations on thermal transfer point out that potential age overestimation due to charge transfer can apparently be neglected for the samples under consideration

  17. 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...

  18. A new hybrid algorithm using thermodynamic and backward ray-tracing approaches for modeling luminescent solar concentrators

    Energy Technology Data Exchange (ETDEWEB)

    Lo, Ch. K.; Lim, Y. S.; Tan, S. G.; Rahman, F. A. [Faculty of Engineering and Science, University Tunku Abdul Rahman, Jalan Genting Klang, 53300, Kuala Lumpur (Malaysia)

    2010-12-15

    A Luminescent Solar Concentrator (LSC) is a transparent plate containing luminescent material with photovoltaic (PV) cells attached to its edges. Sunlight entering the plate is absorbed by the luminescent material, which in turn emits light. The emitted light propagates through the plate and arrives at the PV cells through total internal reflection. The ratio of the area of the relatively cheap polymer plate to that of the expensive PV cells is increased, and the cost per unit of solar electricity can be reduced by 75%. To improve the emission performance of LSCs, simulation modeling of LSCs becomes essential. Ray-tracing modeling is a popular approach for simulating LSCs due to its great ability of modeling various LSC structures under direct and diffuse sunlight. However, this approach requires substantial amount of measurement input data. Also, the simulation time is enormous because it is a forward-ray tracing method that traces all the rays propagating from the light source to the concentrator. On the other hand, the thermodynamic approach requires substantially less input parameters and simulation time, but it can only be used to model simple LSC designs with direct sunlight. Therefore, a new hybrid model was developed to perform various simulation studies effectively without facing the issues arisen from the existing ray-tracing and thermodynamic models. The simulation results show that at least 60% of the total output irradiance of a LSC is contributed by the light trapped and channeled by the LSC. The novelty of this hybrid model is the concept of integrating the thermodynamic model with a well-developed Radiance ray-tracing model, hence making this model as a fast, powerful and cost-effective tool for the design of LSCs. (authors)

  19. Application of photostimulated luminescence (PSL) to detect irradiated molluscs

    International Nuclear Information System (INIS)

    Marchesani, G.; Chiaravalle, A.E.; Chiesa, L.M.

    2011-01-01

    Complete text of publication follows. In contrast to thermally processed foods, irradiation is a cold treatment both to reduce microbiological contamination and to increase the shelf-life of raw seafood. According to the list of States' authorizations molluscs can be irradiated in a range of 0.5 / 3 kGy only in authorized countries (e.g. UK, Belgium and Czech Republic). Therefore the aim of this study is to identify, at different dose levels (0.5, 1, 1.5, 2, 3 kGy), irradiated oysters, clams and mussels using luminescence materials from different sites (shells and pulps) and to determine sample sensitivity for previous screening result confirmation. A total number of 10 samples for each species were analyzed by both procedures: screening and calibrated PSL. Samples were irradiated using a low energy X-ray irradiator (RS-2400, Radsource Inc.) with the following operational settings: 150 kV and 45 mA. Whole pulps were simply dispensed into a clean Petri-dish whereas shells powder required to be fixed as a thick layer with silicone grease. Results obtained showed that screening analysis can be used to identify correctly all irradiated and non irradiated samples. Particularly untreated sample exhibited a sensitivity index from 2 to 4 order of magnitude greater than the exposed sample one, while for exposed specimen calibrated PSL signals, after re-irradiation at defined dose, were of the same order of the first measurement (initial PSL counts). In conclusion mineral debris contaminating pulps and biocarbonates from shells can be considered reliable radioinduced markers and PSL techniques can be easily applied for rapid and simple analysis to identify irradiated molluscs in official controls.

  20. Optically stimulated luminescence of natural NaCl mineral from Dead Sea exposed to gamma radiation

    International Nuclear Information System (INIS)

    Roman L, J.; Cruz Z, E.; Pina L, Y. I.; Marcazzo, J.

    2016-10-01

    Luminescence properties such as radioluminescence, thermoluminescence and optically stimulated luminescence have been studied on natural sodium chloride (NaCl) for dosimetric purposes in retrospective dosimetry (Timar-Gabor et al., 2013; Druzhyna et al., 2016). In this work, the optically stimulated luminescence (Cw-OSL) emissions of natural salt minerals, collected from Dead Sea in summer of 2015, were studied. The Cw-OSL dose response of natural salt was analyzed in the range between 0.2 and 10 Gy gamma dose of "6"0Co. Samples exposed at 3 Gy exhibited good repeatability with a variation coefficient of 4.6%. The thermal stability of the Cw-OSL response was analyzed to different temperatures from 50 up to 250 degrees Celsius using a heating rate of 5 degrees Celsius. The results showed that the natural Dead Sea salt minerals could be applied as natural dosimeter of gamma radiation. (Author)

  1. Optically stimulated luminescence of natural NaCl mineral from Dead Sea exposed to gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Roman L, J.; Cruz Z, E. [UNAM, Instituto de Ciencias Nucleares, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico); Pina L, Y. I. [UNAM, Facultad de Ciencias, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico); Marcazzo, J., E-mail: jesus.roman@nucleares.unam.mx [Instituto de Fisica Arroyo Seco - UNICEN, Pinto 399, 7000 Tandil (Argentina)

    2016-10-15

    Luminescence properties such as radioluminescence, thermoluminescence and optically stimulated luminescence have been studied on natural sodium chloride (NaCl) for dosimetric purposes in retrospective dosimetry (Timar-Gabor et al., 2013; Druzhyna et al., 2016). In this work, the optically stimulated luminescence (Cw-OSL) emissions of natural salt minerals, collected from Dead Sea in summer of 2015, were studied. The Cw-OSL dose response of natural salt was analyzed in the range between 0.2 and 10 Gy gamma dose of {sup 60}Co. Samples exposed at 3 Gy exhibited good repeatability with a variation coefficient of 4.6%. The thermal stability of the Cw-OSL response was analyzed to different temperatures from 50 up to 250 degrees Celsius using a heating rate of 5 degrees Celsius. The results showed that the natural Dead Sea salt minerals could be applied as natural dosimeter of gamma radiation. (Author)

  2. 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

  3. 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

  4. Controlling Second Coordination Sphere Effects in Luminescent Ruthenium Complexes by Means of External Pressure.

    Science.gov (United States)

    Pannwitz, Andrea; Poirier, Stéphanie; Bélanger-Desmarais, Nicolas; Prescimone, Alessandro; Wenger, Oliver S; Reber, Christian

    2018-06-04

    Two luminescent heteroleptic Ru II complexes with a 2,2'-biimidazole (biimH 2 ) ligand form doubly hydrogen-bonded salt bridges to 4-sulfobenzoate anions in single crystals. The structure of one of these cation-anion adducts shows that the biimH 2 ligand is deprotonated. Its 3 MLCT luminescence band does not shift significantly under the influence of an external hydrostatic pressure, a behavior typical for these electronic transitions. In contrast, hydrostatic pressure on the other crystalline cation-anion adduct induces a shift of proton density from the peripheral N-H groups of biimH 2 towards benzoate, leading to a pronounced redshift of the 3 MLCT luminescence band. Such a significant and pressure-tunable influence from an interaction in the second coordination sphere is unprecedented in artificial small-molecule-based systems. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Performance of a novel multiple-signal luminescence sediment tracing method

    Science.gov (United States)

    Reimann, Tony

    2014-05-01

    Optically Stimulated Luminescence (OSL) is commonly used for dating sediments. Luminescence signals build up due to exposure of mineral grains to natural ionizing radiation, and are reset when these grains are exposed to (sun)light during sediment transport and deposition. Generally, luminescence signals can be read in two ways, potentially providing information on the burial history (dating) or the transport history (sediment tracing) of mineral grains. In this study we use a novel luminescence measurement procedure (Reimann et al., submitted) that simultaneously monitors six different luminescence signals from the same sub-sample (aliquot) to infer the transport history of sand grains. Daylight exposure experiments reveal that each of these six signals resets (bleaches) at a different rate, thus allowing to trace the bleaching history of the sediment in six different observation windows. To test the feasibility of luminescence sediment tracing in shallow-marine coastal settings we took eight sediment samples from the pilot mega-nourishment Zandmotor in Kijkduin (South-Holland). This site provides relatively controlled conditions as the morphological evolution of this nourishment is densely monitored (Stive et al., 2013). After sampling the original nourishment source we took samples along the seaward facing contour of the spit that was formed from August 2011 (start of nourishment) to June 2012 (sampling). It is presumed that these samples originate from the source and were transported and deposited within the first year after construction. The measured luminescence of a sediment sample was interpolated onto the daylight bleaching curve of each signal to assign the Equivalent Exposure Time (EET) to a sample. The EET is a quantitative measure of the full daylight equivalent a sample was exposed to during sediment transport, i.e. the higher the EET the longer the sample has been transported or the more efficient it has been exposed to day-light during sediment

  6. Luminescent properties in films of ZrO2: Dy

    International Nuclear Information System (INIS)

    Martinez, R. C.; Guzman, J.; Rivera, T.; Ceron, P.; Montes, E.; Guzman, D.; Garcia H, M.; Falcony, C.; Azorin, J.

    2014-08-01

    In this work the luminescent characterization of zirconium oxide (ZrO 2 ) films impure with dysprosium (Dy +3 ) is reported, obtained by means of the ultrasonics spray pyrolysis technique. The films were deposited on glass substrates (Corning), in a temperatures interval of 400 to 550 grades C, using as precursor elements Zirconium oxide chloride octahydrate (ZrOCl 2 ·8H 2 O) and Dysprosium tri-chloride (DyCl 3 ), dissolved in deionized water, varying the concentration of the contaminated from the 1 to 20 atomic % with relationship to the zirconium in solution. The luminescent characterization was analyzed by means of photoluminescence and thermoluminescence. The photoluminescence results showed a spectrum with three maxima which correspond to the electronic transitions 4 F 9/2 - 6 H 15/2 , 4 F 9/2 - 6 H 13/2 and 4 F 9/2 - 6 H 11/2 characteristics of the Dy 3+ ion. The thermoluminescence (Tl) response when being exposed to a monochrome UV beam in 240 nm showed a wide curve that exhibits a maxim centered in 200 grades C. The Tl response of ZrO 2 :Dy in function of the dose was shown lineal in the interval of 24 mJ/cm 2 to 432 mJ/cm 2 . A study of the repeatability and dissipation of the ZrO 2 :Dy Tl response is included. Considering the shown previous results we can conclude that the ZrO 2 in film form obtained by spray pyrolysis has luminescent properties in 240 nm. (Author)

  7. Change of the dominant luminescent mechanism with increasing current density in molecularly doped organic light-emitting devices

    International Nuclear Information System (INIS)

    Zhou Liang; Zhang Hongjie; Meng Qingguo; Liu Fengyi; Yu Jiangbo; Deng Ruiping; Peng Zeping; Li Zhefeng; Guo Zhiyong

    2007-01-01

    We have fabricated and measured a series of electroluminescent devices with the structure of ITO/TPD/Eu(TTA) 3 phen (x):CBP/BCP/ALQ/LiF/Al, where x is the weight percentage of Eu(TTA) 3 phen (from 0% to 6%). At very low current density, carrier trapping is the dominant luminescent mechanism and the 4% doped device shows the highest electroluminescence (EL) efficiency among all these devices. With increasing current density, Foerster energy transfer participates in EL process. At the current density of 10.0 and 80.0 mA/cm 2 , 2% and 3% doped devices show the highest EL efficiency, respectively. From analysis of the EL spectra and the EL efficiency-current density characteristics, we found that the EL efficiency is manipulated by Foerster energy transfer efficiency at high current density. So we suggest that the dominant luminescent mechanism changes gradually from carrier trapping to Foerster energy transfer with increasing current density. Moreover, the conversion of dominant EL mechanism was suspected to be partly responsible for the EL efficiency roll-off because of the lower EL quantum efficiency of Foerster energy transfer compared with carrier trapping

  8. Synthesis, characterization and luminescence study of Eu3+ doped Y2Sn2O7 nano-particles

    International Nuclear Information System (INIS)

    Nigam, Sandeep; Sudarsan, V.; Vatsa, R.K.

    2011-01-01

    In recent years, advanced materials derived from Pyrochlore-type oxides (A 2 B 2 O 7 ), have been of extensive scientific and technological interest. Chemical substitution of A or B sites of pyrochlore oxide by rare earth ions is a widely used approach to prepare thermally stable, lanthanide ion doped luminescent materials. The present study deals with the synthesis and characterization of Eu 3+ doped Y 2 Sn 2 O 7 : nanoparticles prepared by the hydrolysis of Y 3+ , Sn 4+ , and Eu 3+ in ethylene glycol medium followed by heating at 700 deg C for 4 hours. As prepared samples are amorphous in nature and 700 deg C heated sample showed well crystalline pyrochlore structure in XRD studies. Average particle size is calculated from the width of the X-ray diffraction peaks and found to t be around 5 nm. Luminescence measurements were carried out for as prepared and 700 deg C heated samples. The undoped as prepared sample showed a broad emission peak around 420 nm after excitation at 285 nm. While for 700 deg C undoped heated sample, the peak maxima was shifted to 435 nm. The emission spectrum for doped as prepared samples is characterized by both host emission around 420 nm along with the characteristic Eu 3+ emission peaks in the visible region. However, very poor Eu 3+ emission from heated sample was observed

  9. Fabrication of blue luminescent MoS{sub 2} quantum dots by wet grinding assisted co-solvent sonication

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Junaid; Siddiqui, Ghayas Uddin [Department of Mechatronics Engineering, Jeju National University, Jeju (Korea, Republic of); Choi, Kyung Hyun, E-mail: amm@jejunu.ac.kr [Department of Mechatronics Engineering, Jeju National University, Jeju (Korea, Republic of); Jang, Yunseok [Department of Printed Electronics, Korea Institute of Machinery & Materials, Daejeon, Republic of Korea (Korea, Republic of); Lee, Kangtaek [Department of Chemical and Biomolecular Engineering, Yonsei University (Korea, Republic of)

    2016-01-15

    Molybdenum disulfide (MoS{sub 2}) belongs to transition-metal dichalcogenides (TMDs) family and has vital position among 2D materials. Here, an efficient strategy for the synthesis of zero-dimensional MoS{sub 2} quantum dots (QDs) has been represented. This strategy consists of wet grinding of pristine MoS{sub 2} in N-methyl-2-pyrrolidone (NMP) followed by sonication in NMP and 1,2-dichlorobenzene (o-DCB). The efficacy of this approach to synthesize MoS{sub 2} QDs has been reported by analyzing the as synthesized MoS{sub 2} QDs by different characterization techniques such as high resolution transmission electron microscopy, energy dispersive x-ray spectroscopy, Raman spectroscopy, photoluminescence spectroscopy, Fourier transform infrared spectroscopy and UV–vis spectroscopy. The concentration (yield) of as synthesized MoS{sub 2} QDs was found to be 7 mg mL{sup −1}. Most of the MoS{sub 2} QDs were measured around 2–5 nm in size. The as synthesized MoS{sub 2} QDs showed distinct blue luminescence upon UV excitation. - Highlights: • Synthesis of MoS{sub 2} quantum dots. • Wet grinding of MoS{sub 2} flakes for 6 h in NMP. • Ultrasonication of MoS{sub 2} in NMP and DCB. • Particle size 2–5 nm and concentration 7 mg/ml. • MoS{sub 2} QDs showed blue luminescence.

  10. Remote measurement of canopy reflectance shows the effects of elevated carbon dioxide and ozone on the structure and functioning of soybeans in a field setting.

    Science.gov (United States)

    Gray, S.; Dermody, O.; Delucia, E.

    2006-12-01

    By altering physiological processes and modifying canopy structure, elevated atmospheric CO2 and O3 directly and indirectly change the productivity of agroecosystems. Remote sensing of canopy reflectance can be used to monitor physiological and structural changes in an ecosystem over a growing season. To examine effects of changing tropospheric chemistry on water content, chlorophyll content, and changes in leaf area index (LAI), Free-Air Concentration Enrichment (FACE) technology was used to expose large plots of soybean (Glycine max) to elevated atmospheric CO2, elevated O3 (1.5 x ambient), and combined elevated CO2 and O3. The following indices were calculated from weekly measurements of reflectance: water index (WI), photochemical reflectance index (PRI), chlorophyll index, near-infrared/ red (NIR/red), and normalized difference vegetation index (NDVI). NIR/red and LAI were strongly correlated throughout the growth season; however NDVI and LAI were highly correlated only up to LAI of 3. Exposure to elevated CO2 accelerated early-season canopy development and delayed late-season senescence. Growth in elevated O3 had the opposite effect. Additionally, elevated CO2 compensated for negative effects of O3 when the canopy was exposed to both gases simultaneously. Reflectance indices revealed several physiological and structural responses of this agroecosystem to tropospheric change, and ultimately that elevated CO2 and O3 significantly affected this system's productivity and period for carbon gain.

  11. Retrospective individual dosimetry using luminescence and EPR after radiation accidents

    International Nuclear Information System (INIS)

    Goeksu, H.Y.; Wieser, A.; Ulanovsky, A.

    2007-01-01

    In areas where radiation dose monitoring has not been performed, it is essential to use material available in the environment be able to rapidly assess doses to individuals for immediate emergency medical care or for general estimation of the radiological consequences. It was shown that certain types of telephone cards containing microchips have the potential to be used as individual radiation dosimeters in emergency situations to detect doses over 250 mGy by luminescence measurements. In order to understand the dosimetric properties of chip cards, the components obtained from INFINIEON Company at various stages of production were used for luminescence measurements. It is found that the protecting layer used above the chips so called 'globe top' is the main source of radiation induced signal in chip cards. The globe top produced by INFINIEON at that stage is found to contain SiO2 and Epoxy. In order to improve the dosimetric properties of the chip cards, the raw material of the globe top is mixed with phosphorous material. The variation of the dose response and the detection limit with respect to the amount and the type of the phosphor added to the globe top is investigated using thermo luminescence (TL) and infrared stimulated luminescence (IRSL). Taking into account the rapid changes in chip card producing technology such as material properties, size of the globe top, a special-purpose software tool has been developed to calculate integral free-in-air kerma or organ dose for a given energy dose response of the card and irradiation conditions (photon fluence spectrum and irradiation geometry). It is also shown that adding phosphors powders such as Al2O3:C, LiF:Cu or BeO to SiO2/epoxy mixture of the globe top material, radiation detection limit of chip cards can be reduced as low as a few mGy but the presence of an initial signal in UV cured material as well as gradual increase of the signal are found to be the main limiting factors for detection of low doses

  12. Luminescent decay and spectra of impurity-activated alkali halides under high pressure

    International Nuclear Information System (INIS)

    Klick, D.I.

    1977-01-01

    The effect of high pressure on the luminescence of alkali halides doped with the transition-metal ions Cu + and Ag + and the heavy-metal ions In + and Tl + was investigated to 140 kbar. Measurement of spectra allowed the prediction of kinetic properties, and the predictions agree with lifetime data

  13. 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

  14. Real-Time H2 O2 Measurements in Bone Marrow Mesenchymal Stem Cells (MSCs) Show Increased Antioxidant Capacity in Cells From Osteoporotic Women.

    Science.gov (United States)

    Román, Flavia; Urra, Carla; Porras, Omar; Pino, Ana María; Rosen, Clifford J; Rodríguez, Juan Pablo

    2017-03-01

    Oxidative stress (OS) derived from an increase in intracellular reactive oxygen species (ROS) is a major determinant of aging and lifespan. It has also been associated with several age-related disorders, like postmenopausal osteoporosis of Mesenchymal stem cells (MSCs). MSCs are the common precursors for osteoblasts and adipocytes; appropriate commitment and differentiation of MSCs into a specific phenotype is modulated, among other factors, by ROS balance. MSCs have shown more resistance to ROS than differentiated cells, and their redox status depends on complex and abundant anti-oxidant mechanisms. The purpose of this work was to analyze in real time, H 2 O 2 signaling in individual h-MSCs, and to compare the kinetic parameters of H 2 O 2 management by cells derived from both control (c-) and osteoporotic (o-) women. For these purposes, cells were infected with a genetically encoded fluorescent biosensor named HyPer, which is specific for detecting H 2 O 2 inside living cells. Subsequently, cells were sequentially challenged with 50 and 500 μM H 2 O 2 pulses, and the cellular response was recorded in real time. The results demonstrated adequate expression of the biosensor allowing registering fluorescence from HyPer at a single cell level. Comparison of the response of c- and o-MSCs to the oxidant challenges demonstrated improved antioxidant activity in o-MSCs. This was further corroborated by measuring the relative expression of mRNAs for catalase, superoxide dismutase-1, thioredoxine, and peroxiredoxine, as well as by cell-surviving capacity under short-term H 2 O 2 treatment. We conclude that functional differences exist between healthy and osteoporotic human MSCs. The mechanism for these differences requires further study. J. Cell. Biochem. 118: 585-593, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  15. 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.

  16. 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

  17. Latest developments in silica fibre luminescence dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, D. A.; Abdul S, S. F.; Jafari, S. M.; Alanazi, A. [University of Surrey, Department of Physics, GU2 7XH Guildford, Surrey (United Kingdom); Amouzad M, G. [University of Malaya, Faculty of Engineering, Department of Electrical Engineering, Integrated Lightwave Research Group, 50603 Kuala Lumpur (Malaysia); Addul R, H. A.; Mizanur R, A. K. M.; Zubair, H. T.; Begum, M.; Yusoff, Z.; Omar, N. Y. M. [Multimedia University, Faculty of Engineering, 2010 Cyberjaya, Selangor (Malaysia); Maah, M. J. [University of Malaya, Department of Chemistry, 50603 Kuala Lumpur (Malaysia); Collin, S. [National Physical Laboratory, Hampton Road, Teddington, TW11 OLW Middlesex (United Kingdom); Mat-Sharif, K. A.; Muhd-Yassin, S. Z.; Zulkifli, M. I., E-mail: d.a.bradley@surrey.ac.uk [Telekom Malaysia Research and Development Sdn Bhd., 63000 Cyberjaya, Selangor (Malaysia)

    2015-10-15

    Full text: Using tailor made sub-mm diameter doped-silica fibres, we are carrying out luminescence dosimetry studies for a range of situations, including thermoluminescence (Tl)investigations on a liquid alpha source formed of {sup 223}RaCl (the basis of the Bayer Health care product Xofigo), the Tl response to a 62 MeV proton source and Tl response to irradiation from an {sup 241}Am-Be neutron source. In regard to the former, in accord with the intrinsic high linear energy transfer (Let) and short path length (<100 um) of the α-particles in calcified tissue, the product is in part intended as a bone-seeking radionuclide for treatment of metastatic cancer, offering high specificity and efficacy. The Tl yield of Ge-doped SiO{sub 2} fibres has been investigated including for photonic crystal fibre un collapsed, flat fibres and single mode fibres, these systems offering many advantages over conventional passive dosimetry types. In particular, one can mention comparable and even superior sensitivity, an effective atomic number Z{sub eff} of the silica dosimetric material close to that of bone, and the glassy nature of the fibres offering the additional advantage of being able to place such dosimeters directly into liquid environments. Finally we review the use of our tailor made fibres for on-line radioluminescence measurements of radiotherapy beams. The outcome from these various lines of research is expected to inform development of doped fiber radiation dosimeters of versatile utility, ranging from clinical applications through to industrial studies and environmental evaluations. (Author)

  18. Study of the point defect creation and of the excitonic luminescence in alkali halides irradiated by swift heavy ions; Etude de la creation de defauts ponctuels et de la luminescence excitonique d`halogenures d`alcalins irradies par les ions lourds de grande vitesse

    Energy Technology Data Exchange (ETDEWEB)

    Protin, L

    1994-10-05

    The aim of this experimental thesis is to study the excitonic mechanisms and of the defect creation, in NaCl and KBr, under dense electronic excitations induced by swift heavy ion irradiations. In the first part, we present the main features of the interaction of swift heavy ions with solid targets, and after we review the well known radiolytic processes of the defect creation during X-ray irradiation. In the second chapter, we describe our experimental set-up. In the chapter III, we present our results of the in-situ optical absorption measurements. This results show that defect creation is less sensitive to the temperature than during a classical irradiation. Besides, we observe new mechanisms concerning the defect aggregation. In the chapter IV, we present the results of excitonic luminescence induced by swift by swift heavy ions. We observe that the luminescence yields only change with the highest electronic stopping power. In the chapter V, we perform thermal spike and luminescence yields calculations and we compare the numerical results to the experiments presented in the chapter IV. (author). 121 refs., 65 figs., 30 tabs.

  19. 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

  20. Near-surface layer radiation color centers in lithium fluoride nanocrystals: Luminescence and composition

    Energy Technology Data Exchange (ETDEWEB)

    Voitovich, A.P., E-mail: voitovich@imaph.bas-net.by; Kalinov, V.S.; Stupak, A.P.; Novikov, A.N.; Runets, L.P.

    2015-01-15

    Lithium fluoride nanocrystals are irradiated by gamma quanta at 77 K. The radiation color centers formed in a near-surface layer of nanocrystals are studied. Absorption, luminescence and luminescence excitation spectra of the surface defects have been measured. It has been found that the luminescence excitation spectra for aggregated surface centers consist of two or three bands with not very much different intensities. Reactions of the surface centers separately with electrons and with anion vacancies have been investigated. Numbers of anion vacancies and electrons entering into the centers composition have been established and it has been found that F{sub S1}, F{sub S1}{sup −}, F{sub S2}, F{sub S2}{sup −}, F{sub S3}{sup +} and F{sub S3} types of the surface centers are formed. The degree of luminescence polarization has been defined and it has been determined that the polarization degree for F{sub S2}{sup +} centers changes sign under transition from one excitation band to another. It has been shown that during irradiation at 77 K radiation-induced defects are formed more efficiently on the surface than in the bulk. - Highlights: • Radiative color centers were fabricated in lithium fluoride nanocrystals. • The unique absorption and luminescence characteristics are inherent in the centers. • The reactions of these centers with electrons and anion vacancies were studied. • The degree of luminescence polarization was defined. • Numbers of anion vacancies and electrons forming the centers were established.

  1. Multistate Luminescent Solar Concentrator "Smart" Windows

    NARCIS (Netherlands)

    Sol, Jeroen A.H.P.; Timmermans, Gilles H.; Breugel, van Abraham J.; Schenning, Albertus P.H.J.; Debije, Michael G.

    2018-01-01

    A supertwist liquid crystalline luminescent solar concentrator (LSC) "smart" window is fabricated which can be switched electrically between three states: one designed for increased light absorption and electrical generation (the "dark" state), one for transparency (the "light" state), and one for

  2. Luminescent Solar Concentrators with Fibre Geometry

    NARCIS (Netherlands)

    Edelenbosch, O.Y.; Fisher, M.; Patrignani, L.; Sark, W.G.J.H.M. van; Chatten, A.J.

    2013-01-01

    The potential of a fibre luminescent solar concentrator has been explored by means of both analytical and ray-tracing techniques. Coated fibres have been found to be more efficient than homogeneously doped fibres, at low absorption. For practical fibres concentration is predicted to be linear

  3. Co-precipitation synthesis and upconversion luminescence ...

    Indian Academy of Sciences (India)

    Introduction. Researches of rare-earth-doped upconversion (UC) materials as fluorescent labels, temperature-sensing probes, solid-state lasers and new generation television screens have recently started to be considered1,2 due to their enhanced luminescent properties induced by the small size. UC process is the gener-.

  4. Studies of positron induced luminescence from polymers

    International Nuclear Information System (INIS)

    Xu, J.; Hulett, L.D. Jr.; Lewis, T.A.; Tolk, N.H.

    1994-01-01

    Light emission from polymers (anthracene dissolved in polystryrene) induced by low-energy positrons and electrons has been studied. Results indicate a clear difference between optical emissions under positron and electron bombardment. The positron-induced luminescence spectrum is believed to be generated by both collisional and annihilation processes

  5. Combustion synthesis and preliminary luminescence studies of ...

    Indian Academy of Sciences (India)

    The polycrystalline sample of LiBaPO4 : Tb3+ (LBPT) was successfully synthesized by solution combustion synthesis and studied for its luminescence characteristics. The thermoluminescence (TL) glow curve of LBPT material consists of two peaks at 204.54 and 251.21°C. The optimum concentration was 0.005 mol to ...

  6. 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

  7. Co-precipitation synthesis and upconversion luminescence ...

    Indian Academy of Sciences (India)

    ... light: strong green (539 nm), weak red (670 nm) and near-infrared (760 nm). The upconversion luminescence is based on two-photon absorption by the energy transfer from the donor (Yb3+) to the acceptor (Ho3+). All the results indicate that ZrO2:Yb3+-Ho3+ phosphors could be a promising biological labelling material.

  8. Luminescence of porous silicon doped by erbium

    International Nuclear Information System (INIS)

    Bondarenko, V.P.; Vorozov, N.N.; Dolgij, L.N.; Dorofeev, A.M.; Kazyuchits, N.M.; Leshok, A.A.; Troyanova, G.N.

    1996-01-01

    The possibility of the 1.54 μm intensive luminescence in the silicon dense porous layers, doped by erbium, with various structures is shown. Low-porous materials of both porous type on the p-type silicon and porous silicon with wood-like structure on the n + type silicon may be used for formation of light-emitting structures

  9. Mitochondria Targeting with Luminescent Rhenium(I) Complexes.

    Science.gov (United States)

    Skiba, Joanna; Bernaś, Tytus; Trzybiński, Damian; Woźniak, Krzysztof; Ferraro, Giarita; Marasco, Daniela; Merlino, Antonello; Shafikov, Marsel Z; Czerwieniec, Rafał; Kowalski, Konrad

    2017-05-15

    Two new neutral fac -[Re(CO)₃(phen)L] compounds ( 1 , 2 ), with phen = 1,10-phenanthroline and L = O₂C(CH₂)₅CH₃ or O₂C(CH₂)₄C≡CH, were synthetized in one-pot procedures from fac -[Re(CO)₃(phen)Cl] and the corresponding carboxylic acids, and were fully characterized by IR and UV-Vis absorption spectroscopy, ¹H- and 13 C-NMR, mass spectrometry and X-ray crystallography. The compounds, which display orange luminescence, were used as probes for living cancer HeLa cell staining. Confocal microscopy revealed accumulation of both dyes in mitochondria. To investigate the mechanism of mitochondrial staining, a new non-emissive compound, fac -[Re(CO)₃(phen)L], with L = O₂C(CH₂)₃((C₅H₅)Fe(C₅H₄), i.e., containing a ferrocenyl moiety, was synthetized and characterized ( 3 ). 3 shows the same mitochondrial accumulation pattern as 1 and 2 . Emission of 3 can only be possible when ferrocene-containing ligand dissociates from the metal center to produce a species containing the luminescent fac -[Re(CO)₃(phen)]⁺ core. The release of ligands from the Re center was verified in vitro through the conjugation with model proteins. These findings suggest that the mitochondria accumulation of compounds 1 - 3 is due to the formation of luminescent fac -[Re(CO)₃(phen)]⁺ products, which react with cellular matrix molecules giving secondary products and are uptaken into the negatively charged mitochondrial membranes. Thus, reported compounds feature a rare dissociation-driven mechanism of action with great potential for biological applications.

  10. Mitochondria Targeting with Luminescent Rhenium(I Complexes

    Directory of Open Access Journals (Sweden)

    Joanna Skiba

    2017-05-01

    Full Text Available Two new neutral fac-[Re(CO3(phenL] compounds (1,2, with phen = 1,10-phenanthroline and L = O2C(CH25CH3 or O2C(CH24C≡CH, were synthetized in one-pot procedures from fac-[Re(CO3(phenCl] and the corresponding carboxylic acids, and were fully characterized by IR and UV-Vis absorption spectroscopy, 1H- and 13C-NMR, mass spectrometry and X-ray crystallography. The compounds, which display orange luminescence, were used as probes for living cancer HeLa cell staining. Confocal microscopy revealed accumulation of both dyes in mitochondria. To investigate the mechanism of mitochondrial staining, a new non-emissive compound, fac-[Re(CO3(phenL], with L = O2C(CH23((C5H5Fe(C5H4, i.e., containing a ferrocenyl moiety, was synthetized and characterized (3. 3 shows the same mitochondrial accumulation pattern as 1 and 2. Emission of 3 can only be possible when ferrocene-containing ligand dissociates from the metal center to produce a species containing the luminescent fac­[Re(CO3(phen]+ core. The release of ligands from the Re center was verified in vitro through the conjugation with model proteins. These findings suggest that the mitochondria accumulation of compounds 1–3 is due to the formation of luminescent fac-[Re(CO3(phen]+ products, which react with cellular matrix molecules giving secondary products and are uptaken into the negatively charged mitochondrial membranes. Thus, reported compounds feature a rare dissociation-driven mechanism of action with great potential for biological applications.

  11. 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.

  12. Luminescence spectra of lead tungstate, spodumene and topaz crystals

    International Nuclear Information System (INIS)

    Ramachandran, Vasuki

    2002-01-01

    A detailed set of thermoluminescence, cathodoluminescence and radioluminescence (TL, CLTL and RLTL) data of lead tungstate, Spodumene and Topaz have been reported for the first time over a wide temperature range from 25 to 500K. Lead tungstate (PbWO 4 ), a widely known scintillating material, gives TL glow peaks which are related to complex defect centres. Doping of this crystal with trivalent rare earth ions (La 3+ , Y 3+ ) reduces the slow component of the emission thereby making it more suitable for its applications. The pentavalent dopants on the other hand, enhance the green emission and quench the blue emission at temperatures 100K. The origin and the irradiation temperature definitely have an effect on the spectrum. No strong relationship could be derived from the dose dependence data. Two less studied minerals, Spodumene and Topaz have also been investigated with the luminescence techniques. The glow peak near 250degC is thought to have originated from Mn 2+ centres. As there are no ESR data available, the assignment of defect centres is rather difficult. Cr + acts as the quencher in green spodumene. Topaz had the same treatment as the other two sets of samples and the defect centre characterisation looks complex as each coloured sample gave different patterns of glow peaks. Cathodoluminescence whilst heating (CLTL) of all these samples showed some unusual features in the form of a luminescence intensity step which is believed to have originated from the presence of ice. Water, in nanoparticle size quantities, is present as a contaminant in the lattice and undergoes a phase transition at 170K from hexagonal to cubic structures. This phase change influences the luminescence efficiency of the host material and is reflected in the spectrum as a discontinuity in intensity. (author)

  13. Fabrication and spectroscopic studies on highly luminescent CdSe/CdS nanorod polymer composites

    NARCIS (Netherlands)

    Bomm, J.; Büchtemann, A.; Fiore, Angela; Manna, L.; Nelson, J.H.; Hill, D.; van Sark, W.G.J.H.M.

    2010-01-01

    Highly luminescent nanocomposites were prepared by incorporating CdSe/CdS core/shell nanorods into different polymer matrices. The resulting nanocomposites show high transparency of up to 93%. A photoluminescence quantum efficiency of 70% was obtained, with an optimum combination of nanorod (0.05 wt

  14. Two-photon luminescence microscopy of field enhancement at gold nanoparticles

    DEFF Research Database (Denmark)

    Beermann, Jonas; Bozhevolnyi, Sergey I.

    2005-01-01

    Using a reflection scanning optical microscope detecting two-photon luminescence (TPL) we have imaged square gold bumps positioned in a periodic array either on a smooth gold film or directly on a glass substrate. The second-harmonic (SH) and TPL response from these structures show both...

  15. Assembly and luminescence properties of lanthanide-polyoxometalates/polyethyleneimine/SiO{sub 2} particles with core–shell structure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jun, E-mail: junwang924@yahoo.com.cn; Fan, Shaohua; Zhao, Weiqian; Zhang, Hongyan

    2013-01-01

    In this paper, two lanthanide-polyoxometalate (LnW{sub 10}) complexes were bonded on the surface of the polyethyleneimine (PEI)-modified silica nanoparticles with different sizes, resulting in the formation of LnW{sub 10}/PEI/SiO{sub 2} particles. The hybrid core–shell particles were characterized by infrared, luminescent spectra, scanning electronic microscope, and transmission electronic microscope. The particles obtained exhibit the fine spherical core–shell structure and the excellent luminescence properties. The luminescence spectra studies revealed that the formation of LnW{sub 10}/PEI/SiO{sub 2} particles and the size of particle have an influence on the luminescence properties of lanthanide ions. - Highlights: ► SiO{sub 2}/polyethyleneimine (PEI) shows the chemisorption for Ln-polyoxometalates (LnW{sub 10}). ► The core-shell LnW{sub 10}/PEI/SiO{sub 2} nanoparticles with different sizes were fabricated. ► The hybrid particles exhibit the excellent luminescence properties. ► The sizes of particles affect the luminescence properties of lanthanide ions.

  16. Luminescent hybrid materials functionalized with lanthanide ethylenodiaminotetraacetate complexes containing β-diketonate as antenna ligands

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Franklin P.; Costa, Israel F.; Espínola, José Geraldo P.; Faustino, Wagner M.; Moura, Jandeilson L. [Departamento de Química-Universidade Federal da Paraíba, 58051-970 João Pessoa, PB (Brazil); Brito, Hermi F.; Paolini, Tiago B. [Departamento de Química Fundamental-Instituto de Química da Universidade de São Paulo, 05508-900 São Paulo, SP (Brazil); Felinto, Maria Cláudia F.C. [Instituto de Pesquisas energéticas e Nucleares-IPEN, 05508-900 São Paulo, SP (Brazil); Teotonio, Ercules E.S., E-mail: teotonioees@quimica.ufpb.br [Departamento de Química-Universidade Federal da Paraíba, 58051-970 João Pessoa, PB (Brazil)

    2016-02-15

    Three organic–inorganic hybrid materials based on silica gel functionalized with (3-aminopropyl)trimethoxysilane (APTS), [3-(2-aminoetilamino)-propil]-trimetoxissilano (DAPTS) and 3-[2-(2-aminoetilamino)etilamino] propiltrimetoxysilane (TAPTS) and subsequently modified with EDTA derivative were prepared by nonhomogeneous route and were then characterized. The resulting materials named SilXN-EDTA (X=1 for APTS, 2 for DAPTS and 3 for TAPTS) were used to obtain new lanthanide Ln{sup 3+}-β-diketonate (Ln{sup 3+}=Eu{sup 3+}, Gd{sup 3+} and Tb{sup 3+}) complexes covalently linked to the functionalized silica gel surfaces (named SilXN-EDTALn-dik, dik=tta, dbm, bzac and acac). The photophysical properties of the new luminescent materials were investigated and compared with those with similar system presenting water molecules coordinated to the lanthanide ions, SilXN-EDTALn-H{sub 2}O. The SilXN-EDTAEu-dik and SilXN-EDTATb-dik systems displayed characteristic red and green luminescence when excited by UV radiation. Furthermore, the quantitative results showed that the emission quantum efficiency (η), experimental intensity parameters Ω{sub 2} and Ω{sub 4}, and Einstein's emission coefficient (A{sub 0J}) of the SilXN-EDTAEu-dik materials were largely dependent on the ligands. Based on the luminescence data, the most efficient intramolecular energy transfer processes were found to the SilXN-EDTAEu-dik (dik: tta and dbm) and SilXN-EDTATb-acac materials, which exhibited more pure emission colors. These materials are promising red and green phosphors, respectively. - Highlights: • New highly luminescent hybrid materials containing lanthanide-EDTA complexes. • The effect of three silylanting agent on the adsorption and luminescent properties has been studied. • The luminescence sensitizing by different β-diketonate ligands have been investigated.

  17. 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

  18. Quenching methods for background reduction in luminescence-based probe-target binding assays

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Hong [Los Alamos, NM; Goodwin, Peter M [Los Alamos, NM; Keller, Richard A [Los Alamos, NM; Nolan, Rhiannon L [Santa Fe, NM

    2007-04-10

    Background luminescence is reduced from a solution containing unbound luminescent probes, each having a first molecule that attaches to a target molecule and having an attached luminescent moiety, and luminescent probe/target adducts. Quenching capture reagent molecules are formed that are capable of forming an adduct with the unbound luminescent probes and having an attached quencher material effective to quench luminescence of the luminescent moiety. The quencher material of the capture reagent molecules is added to a solution of the luminescent probe/target adducts and binds in a proximity to the luminescent moiety of the unbound luminescent probes to quench luminescence from the luminescent moiety when the luminescent moiety is exposed to exciting illumination. The quencher capture reagent does not bind to probe molecules that are bound to target molecules and the probe/target adduct emission is not quenched.

  19. A chromosomally based luminescent bioassay for mercury detection in red soil of China

    Energy Technology Data Exchange (ETDEWEB)

    Wei, He [Chinese Academy of Sciences, Nanking (China). State Key Lab. of Soil and Sustainable Agriculture; Nanjing Normal Univ., Nanking (China). College of Life Science; Cheng, Han; Ting, Mao; Zhong, Wen-Hui [Nanjing Normal Univ., Nanking (China). College of Chemistry and Environmental Science; Lin, Xian-Gui [Chinese Academy of Sciences, Nanking (China). State Key Lab. of Soil and Sustainable Agriculture

    2010-07-15

    A luminescent reporter gene system was constructed by fusing the mercury-inducible promoter, P{sub merT}, and its regulatory gene, merR, with a promoterless reporter gene EGFP. A stable and nonantibiotic whole-cell reporter (BMB-ME) was created by introducing the system cassette into the chromosome of Pseudomonas putida strain and then applied it for mercury detection in the red soil of China. Spiked with 10 and 100 {mu}g g{sup -1} Hg{sup 2+} and after 15 and 30 days incubation, soil samples were extracted and evaluated water soluble, bioavailable, organic matter bound, and residual fractions of mercury by both BMB-ME and chemical way. The expression of EGFP was confirmed in soil extraction, and fluorescence intensity was quantified by luminescence spectrometer. The sensor strain BMB-ME appeared to have a detection range similar to that of reversed-phase high-performance liquid chromatography method. The optimal temperature for EGFP expression was 35 C and the lowest detectable concentration of Hg{sup 2+} 200 nM. Cu{sup 2+}, Fe{sup 2+}, Mn{sup 2+}, Sn{sup 2+}, Zn{sup 2+}, Co{sup 2+}, Ag{sup +}, Ba{sup 2+}, Mg{sup 2+}, and Pb{sup 2+} ions at nanomolar level did not interfere with the measurement. These results showed that the BMB-ME constitute an adaptable system for easy sensing of small amounts of mercury in the red soil of China. (orig.)

  20. 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.

  1. Synthesis and characterization of the europium (III) complex as an organic luminescent material

    International Nuclear Information System (INIS)

    Zhuo Zuliang; Zhang Fujun; Xu Zheng; Lu Lifang; Li Junming; Wang Yongsheng; Lv Yuguang

    2010-01-01

    The red emission organic material Eu(coumarin) 3 ·2H 2 O complex was synthesized and its morphology, energy level alignment and luminescence characteristics were studied by using scanning electron microscopy, Fourier transform infrared spectra, cyclic voltammetry and ultraviolet-visible absorption spectra and fluorescence spectra. Eu(coumarin) 3 ·2H 2 O shows bright red emission originating from Eu 3+ ions under 345 nm light excitation. The luminescence lifetime of Eu 3+ in this complex is about 580 μs. To improve the quality of Eu(coumarin) 3 ·2H 2 O thin films, Eu(coumarin) 3 ·2H 2 O was doped with a poly(N-vinylcarbazole) (PVK) solution. The organic materials 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and aluminum quinoline (Alq 3 ) were used as hole-blocking and electron-transporting layers in our fabricated electroluminescence (EL) devices on indium tin oxide (ITO) substrates, respectively. The EL devices ITO/poly-(3,4-ethylenedioxythiophene):poly-(styrenesulphonic acid) (PEDOT:PSS)/emitting layer (PVK:Eu)/BCP/Alq 3 /Al were fabricated, and EL spectra were measured under different driving voltages. There is one emission peaking at 490 nm in addition to the characteristic emission peaks of Eu 3+ , which should be attributed to the spectral overlap between the PVK emission and electroplex emission originating from PVK and BCP interfaces. This explanation can be positively supported by the dependence of the EL spectral variation of ITO/ PVK/BCP/Alq 3 /Al devices on the driving voltage.

  2. Synthesis and characterization of the europium (III) complex as an organic luminescent material

    Science.gov (United States)

    Zhuo, Zuliang; Zhang, Fujun; Lv, Yuguang; Xu, Zheng; Lu, Lifang; Li, Junming; Wang, Yongsheng

    2010-11-01

    The red emission organic material Eu(coumarin)3·2H2O complex was synthesized and its morphology, energy level alignment and luminescence characteristics were studied by using scanning electron microscopy, Fourier transform infrared spectra, cyclic voltammetry and ultraviolet-visible absorption spectra and fluorescence spectra. Eu(coumarin)3·2H2O shows bright red emission originating from Eu3+ ions under 345 nm light excitation. The luminescence lifetime of Eu3+ in this complex is about 580 μs. To improve the quality of Eu(coumarin)3·2H2O thin films, Eu(coumarin)3·2H2O was doped with a poly(N-vinylcarbazole) (PVK) solution. The organic materials 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and aluminum quinoline (Alq3) were used as hole-blocking and electron-transporting layers in our fabricated electroluminescence (EL) devices on indium tin oxide (ITO) substrates, respectively. The EL devices ITO/poly-(3,4-ethylenedioxythiophene):poly-(styrenesulphonic acid) (PEDOT:PSS)/emitting layer (PVK:Eu)/BCP/Alq3/Al were fabricated, and EL spectra were measured under different driving voltages. There is one emission peaking at 490 nm in addition to the characteristic emission peaks of Eu3+, which should be attributed to the spectral overlap between the PVK emission and electroplex emission originating from PVK and BCP interfaces. This explanation can be positively supported by the dependence of the EL spectral variation of ITO/ PVK/BCP/Alq3/Al devices on the driving voltage.

  3. Synthesis and characterization of the europium (III) complex as an organic luminescent material

    Energy Technology Data Exchange (ETDEWEB)

    Zhuo Zuliang; Zhang Fujun; Xu Zheng; Lu Lifang; Li Junming; Wang Yongsheng [Key Laboratory of Luminescence and Optical Information (Beijing Jiaotong University), Ministry of Education, Beijing 100044 (China); Lv Yuguang, E-mail: fjzhang@bjtu.edu.c [The Provincial Key Laboratory of Biomaterials, College of Chemistry and Pharmacy, Jiamusi University, Jiamusi 154007 (China)

    2010-11-15

    The red emission organic material Eu(coumarin){sub 3{center_dot}}2H{sub 2}O complex was synthesized and its morphology, energy level alignment and luminescence characteristics were studied by using scanning electron microscopy, Fourier transform infrared spectra, cyclic voltammetry and ultraviolet-visible absorption spectra and fluorescence spectra. Eu(coumarin){sub 3{center_dot}}2H{sub 2}O shows bright red emission originating from Eu{sup 3+} ions under 345 nm light excitation. The luminescence lifetime of Eu{sup 3+} in this complex is about 580 {mu}s. To improve the quality of Eu(coumarin){sub 3{center_dot}}2H{sub 2}O thin films, Eu(coumarin){sub 3{center_dot}}2H{sub 2}O was doped with a poly(N-vinylcarbazole) (PVK) solution. The organic materials 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and aluminum quinoline (Alq{sub 3}) were used as hole-blocking and electron-transporting layers in our fabricated electroluminescence (EL) devices on indium tin oxide (ITO) substrates, respectively. The EL devices ITO/poly-(3,4-ethylenedioxythiophene):poly-(styrenesulphonic acid) (PEDOT:PSS)/emitting layer (PVK:Eu)/BCP/Alq{sub 3}/Al were fabricated, and EL spectra were measured under different driving voltages. There is one emission peaking at 490 nm in addition to the characteristic emission peaks of Eu{sup 3+}, which should be attributed to the spectral overlap between the PVK emission and electroplex emission originating from PVK and BCP interfaces. This explanation can be positively supported by the dependence of the EL spectral variation of ITO/ PVK/BCP/Alq{sub 3}/Al devices on the driving voltage.

  4. Preliminary results on time-resolved ion beam induced luminescence applied to the provenance study of lapis lazuli

    Energy Technology Data Exchange (ETDEWEB)

    Czelusniak, C. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Palla, L. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Pisa and Università di Pisa, Largo B. Pontecorvo 3, I-56127 Pisa (Italy); Massi, M. [Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Carraresi, L.; Giuntini, L. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Re, A.; Lo Giudice, A. [Dipartimento di Fisica, Università di Torino & INFN Sezione di Torino, Via Giuria 1, 10125 Torino (Italy); Pratesi, G. [Museo di Storia Naturale, Università di Firenze, Via G. La Pira 4, 50121 Firenze (Italy); Mazzinghi, A. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Ruberto, C. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 1, 50019 Sesto Fiorentino, Firenze (Italy); Castelli, L. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); and others

    2016-03-15

    This work will present preliminary results concerning the use of time-resolved ion beam induced luminescence applied to provenance studies of lapis lazuli. Measurements were performed at the pulsed beam facility at LABEC laboratory in Florence. Lapis lazuli is a semi-precious gemstone, used as ornament since the early civilizations that can be found in few places on Earth. The importance of this work lies in understanding the origin of various samples of lapis lazuli, from which it may be possible to gain insight into trade routes from ancient times. The samples studied in this work originated from Chile, Afghanistan, Tajikistan, Myanmar, and Siberia. The stones were irradiated with 3 MeV protons and the resulting luminescence was detected by a photomultiplier tube, whose output was acquired using a sampling digitizer VME module (CAEN/V1720). Wavelength discrimination was performed at 430 nm utilizing a range of beam currents. The results showed that, by changing the beam current intensity, one can study different features of lapis lazuli, and this may aid in distinguishing lapis lazuli from different provenances.

  5. Preliminary results on time-resolved ion beam induced luminescence applied to the provenance study of lapis lazuli

    International Nuclear Information System (INIS)

    Czelusniak, C.; Palla, L.; Massi, M.; Carraresi, L.; Giuntini, L.; Re, A.; Lo Giudice, A.; Pratesi, G.; Mazzinghi, A.; Ruberto, C.; Castelli, L.

    2016-01-01

    This work will present preliminary results concerning the use of time-resolved ion beam induced luminescence applied to provenance studies of lapis lazuli. Measurements were performed at the pulsed beam facility at LABEC laboratory in Florence. Lapis lazuli is a semi-precious gemstone, used as ornament since the early civilizations that can be found in few places on Earth. The importance of this work lies in understanding the origin of various samples of lapis lazuli, from which it may be possible to gain insight into trade routes from ancient times. The samples studied in this work originated from Chile, Afghanistan, Tajikistan, Myanmar, and Siberia. The stones were irradiated with 3 MeV protons and the resulting luminescence was detected by a photomultiplier tube, whose output was acquired using a sampling digitizer VME module (CAEN/V1720). Wavelength discrimination was performed at 430 nm utilizing a range of beam currents. The results showed that, by changing the beam current intensity, one can study different features of lapis lazuli, and this may aid in distinguishing lapis lazuli from different provenances.

  6. Zinc(II) halide complexes with 2-methoxyaniline ligand: Synthesis, characterization, thermal analyses, crystal structure determination and luminescent properties

    Science.gov (United States)

    Amani, Vahid

    2018-03-01

    Three new mononuclear zinc(II) complexes, [Zn(2-MeO-C6H4NH2)2X2] (X is Cl in 1, Br in 2 and I in 3), were prepared from the reactions of ZnX2 with 2-methoxyaniline (2-MeO-C6H4NH2) ligand in methanol. Suitable crystals of these complexes were obtained for X-ray diffraction measurements by slow evaporation of methanol solution at room temperature. The three complexes were thoroughly characterized by thermogravimetric analysis, elemental analysis (CHNO), spectral methods (IR, UV-Vis, 13C{1H}NMR, 1H NMR and luminescence), and single crystal X-ray diffraction. The X-ray structural analysis indicated that in the structures of these complexes, the zinc(II) cation is four-coordinated in a distorted tetrahedral configuration by two N atoms from two 2-methoxyanyline ligands and two halide anions. Also, in these complexes intermolecular interactions, for example Nsbnd H⋯X hydrogen bonds (in 1-3), Csbnd H⋯X hydrogen bonds (in 3), Csbnd H⋯π interactions (in 1 and 2) and π⋯π interactions (in 3), are effective in the stabilization of the crystal structures. In addition, the luminescence spectra of all complexes in methanolic solution show that the intensity of their emission bands is stronger than that for free 2-methoxyaniline ligand.

  7. Synthesis, Structural Characterization and Up-Conversion Luminescence Properties of NaYF4:Er3+,Yb3+@MOFs Nanocomposites

    Science.gov (United States)

    Giang, Lam Thi Kieu; Marciniak, Lukasz; Huy, Tran Quang; Vu, Nguyen; Le, Ngo Thi Hong; Binh, Nguyen Thanh; Lam, Tran Dai; Minh, Le Quoc

    2017-10-01

    This paper describes a facile synthesis of NaYF4:Er3+,Yb3+ nanoparticles embraced in metal-organic frameworks (MOFs), known as NaYF4:Er3+, Yb3+@MOFs core/shell nanostructures, by using iron(III) carboxylate (MIL-100) and zeolitic imidazolate frameworks (ZIF-8). Morphological, structural and optical characterization of these nanostructures were investigated by field emission-scanning electron microscopy, Fourier transform infrared spectroscopy, x-ray diffraction, and up-conversion luminescence measurements. Results showed that spherical-shaped NaYF4:Er3+,Yb3+@MIL-100 nanocomposites with diameters of 150-250 nm, and rod-shaped NaYF4:Er3+,Yb3+@ZIF-8 nanocomposites with lengths of 300-550 nm, were successfully synthesized. Under a 980-nm laser excitation at room temperature, the NaYF4:Er3+,Yb3+@MOFs nanocomposites exhibited strong up-conversion luminescence with two emission bands in the green part of spectrum at 520 nm and 540 nm corresponding to the 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 transitions of Er3+ ions, respectively, and a red emission band at 655 nm corresponding to the 4F9/2 → 4I15/2 transition of Er3+ ions. The above properties of NaYF4:Er3+,Yb3+@MOFs make them promising candidates for applications in biotechnology.

  8. Luminescence characteristics of quartz from the Southern Kenyan Rift Valley: Dose estimation using LM-OSL SAR

    International Nuclear Information System (INIS)

    Choi, J.H.; Duller, G.A.T.; Wintle, A.G.; Cheong, C.-S.

    2006-01-01

    Linearly modulated (LM) optically stimulated luminescence (OSL) measurements have revealed that some sedimentary quartz samples from the Kenyan Rift Valley do not have a fast OSL component, but contain a medium component and several slow components. It was impossible to recover a known dose for these samples using the conventional single-aliquot regenerative-dose (SAR) procedure. The dose-response curves and continuous wave (CW) OSL decay curves for these samples showed several undesirable properties for dating. We have compared various luminescence characteristics of these samples with other quartz samples from elsewhere in the world for which the SAR procedure has been shown to be appropriate; the latter were dominated by a fast OSL component. The characteristics include photoionisation cross-sections for each component and the relative proportions of the different components in the initial and total OSL signals. It was found that those samples that had greater than 90% of the initial 0.8 s of their OSL signal from the fast component were suitable for dating using the conventional SAR protocol. A novel method of displaying the relative contributions of the different OSL components in a ternary diagram is proposed. The thermal stability of each component was investigated using pulse-annealing experiments. We then examined the possibility of applying an LM-OSL SAR protocol to samples that have a substantial medium component

  9. Influence of band-gap grading on luminescence properties of Cu(In,Ga)Se{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Haarstrich, Jakob; Metzner, Heiner; Ronning, Carsten [Institut fuer Festkoerperphysik, Friedrich Schiller Universitaet Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Rissom, Thorsten; Kaufmann, Christian A.; Schock, Hans-Werner [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Solar Energy Research, Institute for Technology, Lise-Meitner-Campus, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Undisz, Andreas [Institute for Material Science and Technology, Metallic Materials, Friedrich-Schiller-University Jena, Loebdergraben 32, 07743 Jena (Germany)

    2011-07-01

    Cathodoluminescence (CL) has been measured on Cu(In,Ga)Se{sub 2} with Ga-grading as it is used in high-efficiency thin-film solar cells at 10 K in both cross-section and plain view configuration. In cross-section geometry, we show that the vertical profile of the emission energy represents the Ga-profile in the film and, thus, we are able to measure the band-gap grading present by means of CL methods. At the same time, we observe a strong drift of excited charge carriers towards the minimum of the band-gap which can be explained by the Ga-grading. It is shown by voltage-dependent CL, how these results directly influence the interpretation of luminescence spectra obtained on Ga-graded Cu(In,Ga)Se{sub 2} and, thus, they will have to be considered as a basis for all forthcoming investigations on this topic.

  10. Optimization of Temperature Sensing with Polymer-Embedded Luminescent Ru(II Complexes

    Directory of Open Access Journals (Sweden)

    Nelia Bustamante

    2018-02-01

    Full Text Available Temperature is a key parameter in many fields and luminescence-based temperature sensing is a solution for those applications in which traditional (mechanical, electrical, or IR-based thermometers struggle. Amongst the indicator dyes for luminescence thermometry, Ru(II polyazaheteroaromatic complexes are an appealing option to profit from the widespread commercial technologies for oxygen optosensing based on them. Six ruthenium dyes have been studied, engineering their structure for both photostability and highest temperature sensitivity of their luminescence. The most apt Ru(II complex turned out to be bis(1,10-phenanthroline(4-chloro-1,10-phenanthrolineruthenium(II, due to the combination of two strong-field chelating ligands (phen and a substituent with electron withdrawing effect on a conjugated position of the third ligand (4-Clphen. In order to produce functional sensors, the dye has been best embedded into poly(ethyl cyanoacrylate, due to its low permeability to O2, high temperature sensitivity of the indicator dye incorporated into this polymer, ease of fabrication, and excellent optical quality. Thermosensitive elements have been fabricated thereof as optical fiber tips for macroscopic applications (water courses monitoring and thin spots for microscopic uses (temperature measurements in cell culture-on-a-chip. With such dye/polymer combination, temperature sensing based on luminescence lifetime measurements allows 0.05 °C resolution with linear response in the range of interest (0–40 °C.

  11. 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

  12. A CaS : Ce, Sm-based dosimeter for online dosimetry measurement

    International Nuclear Information System (INIS)

    Sun Yurun; Chen Zhaoyang; Fan Yanwei; Yan Shiyou; He Chengfa

    2011-01-01

    A film dosimeter based on optically stimulated luminescence (OSL) material of CaS : Ce, Sm was developed for online irradiation dosimetry measurement. The stimulation is provided by a laser with a wavelength of 980 nm, and the OSL luminescence is collected by a photodiode. Using 60 Co γ-rays, we investigated the dosimetry characteristic of the dosimeter at different dose rates and total doses. The real-time detection results showed that the OSL signals versus total ionizing dose exhibited a good linearity in a dose range of 0.1-185 Gy. (authors)

  13. 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.

  14. Show-Bix &

    DEFF Research Database (Denmark)

    2014-01-01

    The anti-reenactment 'Show-Bix &' consists of 5 dias projectors, a dial phone, quintophonic sound, and interactive elements. A responsive interface will enable the Dias projectors to show copies of original dias slides from the Show-Bix piece ”March på Stedet”, 265 images in total. The copies are...

  15. Luminescence dating of the lacustrine record of Vršac (Carpathian Basin, Serbia) - implications for a palaeoenvironmetal reconstruction

    Science.gov (United States)

    Klasen, N.; Zeeden, C.; Markovic, S.; Fischer, P.; Lehmkuhl, F.; Schulte, P.; Bösken, J.; Hambach, U.; Vött, A.

    2017-12-01

    The Carpathian Basin is one of the key areas to investigate the influence of the continental, Mediterranean and Atlantic climate interaction over Europe. The available Upper Pleistocene and Holocene geoarchives in the region are mainly loess-paleosol records. Long lacustrine records are sparse and do not always span the whole last glacial cycle. In the area around Vršac, we drilled a 10 m core to contribute to the palaeoenvironmental reconstruction of the Carpathian Basin. Electrical Resistivity Tomography (ERT) was used to find the best-suited drilling location. We applied luminescence and radiocarbon dating, because a robust chronology is important for the interpretation of the sedimentary record. Pulsed OSL measurements were carried out to identify the best sampling positions. We expect runoff from the catchment being the main source of the lacustrine sediments, because coarse fluvial input is absent. Knowledge about the depositional conditions is important in luminescence dating to evaluate partial bleaching prior to deposition, which may cause age overestimation. Therefore, we compared infrared stimulated luminescence (IRSL) signals with post infrared infrared stimulated luminescence (pIRIR) signals, which bleach at different rates. Estimation of a representative water content has major influence on the age estimate, but remains challenging in luminescence dating. We measured the present day water content as well as the saturation water content, to account for variations over time. Luminescence and radiocarbon ages differ greatly from each other. According to the laboratory experiments, luminescence dating was reliable and we conclude that radiocarbon ages were underestimated because of an intrusion of younger organic material. The initial results demonstrated the potential of the drill core. Integrating more proxy data will be useful to enhance the importance of the geoarchive at Vršac for a better understanding of the last glacial cycle in the Carpathian

  16. Optically stimulated luminescence in electronic components for emergency dosimetry

    International Nuclear Information System (INIS)

    Geber-Bergstrand, T.; Bernhardsson, C.; Mattsson, S.; Raeaef, C.L.

    2015-01-01

    Document available in abstract form only. Full text of publication follows: Accidents and, luckily more rarely, attacks involving nuclear or radiological material do occur from time to time. A very possible consequence of an accident or attack of this kind is that nearby people might be exposed to ionising radiation. Since these types of exposure situations, unlike the ones occurring in medicine, are unplanned, there are no radiation-monitoring data available. For several reasons, it is nevertheless of value to find out the dose that these people have received. The first and most urgent reason is after-the-event triage, to be able to carry out proper medical treatments and also to focus the available medical assets to the persons needing it the most. This is where different retrospective dosimetry techniques, such as luminescence, can be employed. Various electronic components from mobile phones and other portable devices have been studied using optically stimulated luminescence for their potential use in retrospective dosimetry. Previous investigations have been performed in laboratory conditions and have showed very promising properties for emergency dosimetry. In this study, the more practical parts of using electronic components in retrospective dosimetry have been considered. In a triage situation, one of the key parameters to consider is time; thus, effort has been made to speed up the readout procedure, yet without the loss of too much accuracy. (authors)

  17. Biosynthesis of luminescent quantum dots in an earthworm

    Science.gov (United States)

    Stürzenbaum, S. R.; Höckner, M.; Panneerselvam, A.; Levitt, J.; Bouillard, J.-S.; Taniguchi, S.; Dailey, L.-A.; Khanbeigi, R. Ahmad; Rosca, E. V.; Thanou, M.; Suhling, K.; Zayats, A. V.; Green, M.

    2013-01-01

    The synthesis of designer solid-state materials by living organisms is an emerging field in bio-nanotechnology. Key examples include the use of engineered viruses as templates for cobalt oxide (Co3O4) particles, superparamagnetic cobalt-platinum alloy nanowires and gold-cobalt oxide nanowires for photovoltaic and battery-related applications. Here, we show that the earthworm's metal detoxification pathway can be exploited to produce luminescent, water-soluble semiconductor cadmium telluride (CdTe) quantum dots that emit in the green region of the visible spectrum when excited in the ultraviolet region. Standard wild-type Lumbricus rubellus earthworms were exposed to soil spiked with CdCl2 and Na2TeO3 salts for 11 days. Luminescent quantum dots were isolated from chloragogenous tissues surrounding the gut of the worm, and were successfully used in live-cell imaging. The addition of polyethylene glycol on the surface of the quantum dots allowed for non-targeted, fluid-phase uptake by macrophage cells.

  18. UV luminescence of dendrimer-encapsulated gold nanoclusters

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Hyeong Seop; Kim, Jun Myung; Sohn, So Hyeong; Han, Noh Soo; Park, Seung Min [Dept. of Chemistry, Kyung Hee University, Seoul (Korea, Republic of)

    2016-10-15

    Size-dependent luminescence color is one of the interesting properties of metal nanocrystals, whose sizes are in the dimension of the Fermi wavelength of an electron. Despite the short Fermi wavelength of electrons in gold (-0.7 nm), luminescence of gold nanoclusters has been reported to range from the near-infrared to near-ultraviolet, depending on the number of atoms in the nanoclusters. The photoluminescence of G4-OH (Au) obtained by the excitation of 266 nm showed UV emission in addition to the well-known blue emission. The higher intensity and red-shifted emission of the gold nanoclusters was distinguished from the emission of dendrimers. The UV emission at 352 nm matched the emission energy of Au{sub 4} in the spherical jellium model, rather than the planar Au{sub 8}, which supported the emission of Au{sub 4} formed in G4-OH. Despite the change of [HAuCl{sub 4} ]/[G4-OH], the relative population between Au{sub 4} and Au{sub 8} was similar in G4-OH(Au), which indicated that the closed electronic and geometric structures stabilized the magic number of Au{sub 4}.

  19. Highly luminescent Eu{sup 3+}-doped benzenetricarboxylate based materials

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Ivan G.N. [Departamento de Química Fundamental, Instituto de Química da Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo 05508-900, SP (Brazil); Mustafa, Danilo, E-mail: dmustafa@iq.usp.br [Departamento de Química Fundamental, Instituto de Química da Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo 05508-900, SP (Brazil); Andreoli, Bruno [Departamento de Química Fundamental, Instituto de Química da Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo 05508-900, SP (Brazil); Felinto, Maria C.F.C. [Centro de Química do Meio Ambiente, Instituto de Pesquisas Energéticas e Nucleares, Av. Prof. Lineu Prestes 2242, São Paulo 05508-000, SP (Brazil); Malta, Oscar L. [Departamento de Química Fundamental, Universidade Federal de Pernambuco, Av. Prof. Moraes Rego, 1235, Recife 50670-90, PE (Brazil); Brito, Hermi F., E-mail: hefbrito@iq.usp.br [Departamento de Química Fundamental, Instituto de Química da Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo 05508-900, SP (Brazil)

    2016-02-15

    [RE(TMA)] anhydrous complexes (RE{sup 3+}: Y, Gd and Lu) present high red emission intensity with a quantum efficiency (~45%) for the [Y(TMA):Eu{sup 3+}] complexes, due to the absence of non-radioactive decay pathways mediated by water molecules. The complexes were prepared in mild conditions. All the compounds are crystalline and thermostable up to 460 °C. Phosphorescence data of the complexes with Y, Gd and Lu show that the T{sub 1} state of the TMA{sup 3−} anion has energy higher than the {sup 5}D{sub 0} emitting level of the Eu{sup 3+} ion, indicating that the ligand can act as an intramolecular energy sensitizer. The photoluminescence properties of the doped materials were studied based on the excitation and emission spectra and luminescence decay curves. The experimental intensity parameters (Ω{sub λ}), lifetimes (τ), radiative (A{sub rad}) and non-radiative (A{sub nrad}) decay rates were determined and discussed. - Highlights: • Highly luminescent Europium doped anhydrous complexes. • Efficient monochromatic red light conversion molecular devices (LCMDs). • High emission quantum efficiencies.

  20. Influence of electric field on the properties of the polymer stabilized luminescent quantum dots in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Zharkova, Irina S.; Markina, Natalia E. [Saratov State University, Astrakhanskaya 83, 410012 Saratov (Russian Federation); Markin, Alexey V., E-mail: av_markin@mail.ru [Saratov State University, Astrakhanskaya 83, 410012 Saratov (Russian Federation); Drozd, Daniil D.; Speranskaya, Elena S. [Saratov State University, Astrakhanskaya 83, 410012 Saratov (Russian Federation); Goryacheva, Irina Yu. [Saratov State University, Astrakhanskaya 83, 410012 Saratov (Russian Federation); Saint-Petersburg State University, Universitetskii pr. 26, 198504 Petrodvorets, Saint-Petersburg (Russian Federation)

    2016-08-15

    The application of external electric field for verification of quantum dots (QDs) stability in aqueous medium was proposed. Hydrophilic CdSe core-shell nanocrystals were synthesized and used with three polymer-based organic stabilizers, two of which contain PEG chains. An increasing of the stability under applied electric field (EF) was shown for stabilizer containing higher amount of PEG chains and terminal amino-groups: introduction of additional PEG chains allowed reducing degradation of luminescence intensity for about 60%. The changes of QDs solutions after EF treatment were examined by dynamic light scattering measurements, luminescence and absorbance spectroscopy, and conductivity measurements and explained by decreasing of quantum yield of the samples due to degradation of stabilizer coating. - Highlights: • Hydrophilic QDs with three types of stabilizer coatings were prepared and treated by electric field in water environment. • Permanent QDs luminescence quenching in aqueous medium under low electric field strength was observed. • Luminescence stability to EF treatment increases by stabilizer with higher PEG content. • Redox mechanism of luminescence quenching was proved via conductivity, DLS, and UV-visible absorbance measurements.