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Sample records for laser-induced fluorescence line

  1. Laser-induced fluorescence line narrowing in atomic vapors

    International Nuclear Information System (INIS)

    Meier, T.; Schuessler, H.A.

    1983-01-01

    The use of highly monochromatic light allows the selective excitation of atoms in vapors if excitation and detection of the fluorescence is carried out collinearly. The atoms capable of absorbing light then form an atomic beam of well defined velocity along the direction of the laser beam, but no velocity selection occurs perpendicular to it. The potential of the technique for Doppler-free atomic spectroscopy and for the study of excited atom collisions is demonstrated using the Na D 1 line as an example

  2. A method for the measurement of in line pistachio aflatoxin concentration based on the laser induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Paghaleh, Soodeh Jamali; Askari, Hassan Ranjbar; Marashi, Seyed Mohammad Bagher; Rahimi, Mojtaba; Bahrampour, Ali Reza

    2015-01-01

    Contamination of pistachio nuts with aflatoxin is one of the most significant issues related to pistachio health and expert. A fast pistachio aflatoxin concentration measurement method based on the laser induced fluorescence spectroscopy (LIFS) is proposed. The proposed method from theoretical and experimental points of view is analyzed. In our experiments XeCl Excimer laser is employed as an Ultra Violet (UV) source (λ=308 nm) and a UV–visible (UV–vis) spectrometer is used for fluorescent emission detection. Our setup is employed to measure the concentration of different type of Aflatoxins in pistachio nuts. Measurements results obtained by the LIFS method are compared with those are measured by the standard HPLC method. Aflatoxins concentrations are in good agreement with those are obtained by the HPLC method. The proposed laser induced fluorescence spectroscopy can be used as an in line aflatoxins concentrations measurement instrument for industrial applications. - Highlights: • XeCl Excimer laser is employed as an UV source for measurement of AFs in pistachio nuts. • Results are compared with those are measured by the standard HPLC method. • LIFS is an online AFs concentration measurement method for industrial applications

  3. Laser induced fluorescence of dental caries

    Science.gov (United States)

    Albin, S.; Byvik, C. E.; Buoncristiani, A. M.

    1988-01-01

    Significant differences between the optical spectra taken from sound regions of teeth and carious regions have been observed. These differences appear both in absorption and in laser induced fluorescence spectra. Excitation by the 488 nm line of an argon ion laser beam showed a peak in the emission intensity around 553 nm for the sound dental material while the emission peak from the carious region was red-shifted by approximately 40 nm. The relative absorption of carious region was significantly higher at 488 nm; however its fluorescence intensity peak was lower by an order of magnitude compared to the sound tooth. Implications of these results for a safe, reliable and early detection of dental caries are discussed.

  4. Laser induced fluorescence spectroscopy for FTU

    International Nuclear Information System (INIS)

    Hughes, T.P.

    1995-07-01

    Laser induced fluorescence spectroscopy (LIFS) is based on the absorption of a short pulse of tuned laser light by a group of atoms and the observation of the resulting fluorescence radiation from the excited state. Because the excitation is resonant it is very efficient, and the fluorescence can be many times brighter than the normal spontaneous emission, so low number densities of the selected atoms can be detected and measured. Good spatial resolution can be achieved by using a narrow laser beam. If the laser is sufficiently monochromatic, and it can be tuned over the absorption line profile of the selected atoms, information can also be obtained about the velocities of the atoms from the Doppler effect which can broaden and shift the line. In this report two topics are examined in detail. The first is the effect of high laser irradiance, which can cause 'power broadening' of the apparent absorption line profile. The second is the effect of the high magnetic field in FTU. Detailed calculations are given for LIFS of neutral iron and molybdenum atoms, including the Zeeman effect, and the implementation of LIFS for these atoms on FTU is discussed

  5. Laser induced fluorescence of some plant leaves

    International Nuclear Information System (INIS)

    Helmi, M.S.; Mohamed, M.M.; Amer, R.; Elshazly, O.; Elraey, M.

    1992-01-01

    Laser induced fluorescence (LIF) is successfully used as a technique for remote detection of spectral characteristics of some plants. A pulsed nitrogen laser at 337.1 nm is used to excite cotton, corn and rice leaves. The fluorescence spectrum is detected in the range from 340 nm to 820 nm. It is found that, these plant leaves have common fluorescence maxima at 440 nm, 685 nm and 740 nm. plant leaves are also found to be identifiable by the ratio of the fluorescence intensity at 440 nm to that at 685 nm. The present technique can be further used as a means of assessing, remotely, plant stresses. 5 fig

  6. Laser-induced fluorescence imaging of bacteria

    Science.gov (United States)

    Hilton, Peter J.

    1998-12-01

    This paper outlines a method for optically detecting bacteria on various backgrounds, such as meat, by imaging their laser induced auto-fluorescence response. This method can potentially operate in real-time, which is many times faster than current bacterial detection methods, which require culturing of bacterial samples. This paper describes the imaging technique employed whereby a laser spot is scanned across an object while capturing, filtering, and digitizing the returned light. Preliminary results of the bacterial auto-fluorescence are reported and plans for future research are discussed. The results to date are encouraging with six of the eight bacterial strains investigated exhibiting auto-fluorescence when excited at 488 nm. Discrimination of these bacterial strains against red meat is shown and techniques for reducing background fluorescence discussed.

  7. Laser induced fluorescence of trapped molecular ions

    International Nuclear Information System (INIS)

    Grieman, F.J.

    1979-10-01

    An experimental apparatus for obtaining the optical spectra of molecular ions is described. The experimental technique includes the use of three dimensional ion trapping, laser induced fluorescence, and gated photon counting methods. The ions, which are produced by electron impact, are confined in a radio-frequency quadrupole ion trap of cylindrical design. Because the quadrupole ion trap allows mass selection of the molecular ion desired for study, the analysis of the spectra obtained is greatly simplified. The ion trap also confines the ions to a region easily probed by a laser beam. 18 references

  8. Laser induced fluorescence of trapped molecular ions

    Energy Technology Data Exchange (ETDEWEB)

    Grieman, F.J.

    1979-10-01

    An experimental apparatus for obtaining the optical spectra of molecular ions is described. The experimental technique includes the use of three dimensional ion trapping, laser induced fluorescence, and gated photon counting methods. The ions, which are produced by electron impact, are confined in a radio-frequency quadrupole ion trap of cylindrical design. Because the quadrupole ion trap allows mass selection of the molecular ion desired for study, the analysis of the spectra obtained is greatly simplified. The ion trap also confines the ions to a region easily probed by a laser beam. 18 references.

  9. Instantaneous temperature field measurements using planar laser-induced fluorescence.

    Science.gov (United States)

    Seitzman, J M; Kychakoff, G; Hanson, R K

    1985-09-01

    A single-pulse, laser-induced-fluorescence diagnostic for the measurement of two-dimensional temperature fields in combustion flows is described. The method uses sheet illumination from a tunable laser to excite planar laserinduced fluorescence in a stable tracer molecule, seeded at constant mole fraction into the flow field. The temporal resolution of this technique is determined by the laser pulse length. Experimental results are presented for a rodstabilized, premixed methane-air flame, using the Q(1) (22) line of the nitric oxide A(2) Sigma(+) (v = 0) ? X(2)II((1/2))(v = 0) transition (lambda approximately 225.6 nm).

  10. Laser-induced fluorescence for medical diagnostics

    International Nuclear Information System (INIS)

    Andersson Engels, S.

    1989-12-01

    Laser-induced fluorescence as a tool for tissue diagnostics is discussed. Both spectrally and time-resolved fluorescence signals are studied to optimize the demarcation of diseased lesions from normal tissue. The presentation is focused on two fields of application: the identification of malignant tumours and atherosclerotic plaques. Tissue autofluorescence as well as fluorescence from administered drugs have been utilized in diseased tissue diagnosis. The fluorescence criterion for tissue diagnosis is, as far as possible, chosen to be independent of unknown fluorescence parameters, which are not correlated to the type of tissue investigated. Both a dependence on biological parameters, such as light absorption in blood, and instrumental characteristics, such as excitation pulse fluctuations and detection geometry, can be minimized. Several chemical compounds have been studied in animal experiments after intraveneous injection to verify their capacity as malignant tumour marking drugs under laser excitation and fluorescence detection. Another objective of these studies was to improve our understanding of the mechanism and chemistry behind the retention of the various drugs in tissue. The properties of a chemical which maximize its selective retention in tumours are discussed. In order to utilize this diagnostic modality, three different clinically adapted sets of instrumentation have been developed and are presented. Two of the systems are nitrogen-laser-based fluorosensors; one is a point-monitoring system with full spectral resolution and the other one is an imaging system with up to four simultaneously recorded images in different spectral bands. The third system is a low-cost point-monitoring mercury-lamp-based fluoroscence emission as well as reflection characteristics of tissue. (author)

  11. Laser induced fluorescence of trapped molecular ions

    International Nuclear Information System (INIS)

    Winn, J.S.

    1980-10-01

    Laser induced fluoresence (LIF) spectra (laser excitation spectra) are conceptually among the most simple spectra to obtain. One need only confine a gaseous sample in a suitable container, direct a laser along one axis of the container, and monitor the sample's fluorescence at a right angle to the laser beam. As the laser wavelength is changed, the changes in fluorescence intensity map the absorption spectrum of the sample. (More precisely, only absorption to states which have a significant radiative decay component are monitored.) For ion spectroscopy, one could benefit in many ways by such an experiment. Most optical ion spectra have been observed by emission techniques, and, aside from the problems of spectral analysis, discharge emission methods often produce the spectra of many species, some of which may be unknown or uncertain. Implicit in the description of LIF given above is certainty as to the chemical identity of the carrier of the spectrum. This article describes a method by which the simplifying aspects of LIF can be extended to molecular ions

  12. Peroxy Radical Measurements via Laser Induced Fluorescence

    Science.gov (United States)

    Trawny, Katrin; Tatum Ernest, Cheryl; Novelli, Anna; Elste, Thomas; Plaß-Dülmer, Christian; Rudolf, Markus; Martinez, Monica; Harder, Hartwig; Lelieveld, Jos

    2013-04-01

    We present a newly built Laser Induced Fluorescence (LIF) system to measure the sum of all peroxy radicals (RO2) utilizing chemical conversion to OH. This instrument operates in two different modes: the ROx mode (sum of OH, HO2, and RO2) and the HOx mode (sum of OH and HO2). The HOx mode is used to derive the RO2 data from the ROx measurements. A model approach was used during instrumental development to identify the key parameters needed for the conversion process in front of the detection area and to optimize sensitivity. The instrument was then carefully characterized in various lab experiments, where it could be shown that the wall losses for HO2 are negligible and that nearly all HO2 is converted to OH in front of the detection zone. The pressure and temperature dependencies were also analyzed and assured that the instrument does not show any photolytical interference. As the instrument is calibrated with only one kind of peroxy radicals it was very important that the differences in sensitivity for different peroxy radicals are acceptable. Lab experiments as well as first results from the HOPE 2012 intensive field campaign, which took place in summer 2012 at the Global Atmosphere Watch (GAW) station of the German Weather Service, will be discussed.

  13. Laser induced fluorescence in atmospheric pressure discharges

    International Nuclear Information System (INIS)

    Dilecce, G; De Benedictis, S; Martini, L M; Tosi, P; Scotoni, M

    2015-01-01

    This paper offers an outline of laser induced fluorescence (LIF) diagnostics and practical recommendations for its use in atmospheric pressure discharges. LIF principles, technical requirements and rationalization of experimental outcomes by modelling are addressed. Important issues that are particularly relevant to small scale, spatially inhomogeneous discharges, like plasma-jets, are emphasized. For the first time, all collision processes and the spatial non-homogeneity of the laser beam are together accounted for in the LIF model. Saturation characteristics are discussed and used for the assessment of model parameters. A calibration procedure is discussed and implemented. Gas temperature measurements by LIF are also addressed. The whole description of the technique is given, without loss of generality, through the example of its application to the OH radical. Notes on other diatomic radicals, CH, NO and CN, are given along the paper. Some results in a RF plasma-jet are presented as an example of application in a discharge system where all the concepts developed in the paper are applied. (paper)

  14. Laser induced uranium fluorescence as an analytical method

    International Nuclear Information System (INIS)

    Krutman, I.

    1985-01-01

    A laser induced fluorescence system was developed to measure uranium trace level amounts in aqueous solution with reliable and simple materials and electronics. A nitrogen pulsed laser was built with the storage energy capacitor directly coupled to laser tube electrodes as a transmission line device. This laser operated at 3Hz repetition rate with peak intensity around 21 Kw and temporal width of 4.5 x 10 -9 s. A sample compartment made of rigid PVC and a photomultiplier housing of aluminium were constructed and assembled forming a single integrated device. As a result of this prototype system we made several analytical measurements with U dissolved in nitric acid to obtain a calibration curve. We obtained a straight line from a plot of U concentration versus fluorescence intensity fitted by a least square method that produced a regression coefficient of 0.994. The lower limit of U determination was 30 ppb -+ 3.5%. (Author) [pt

  15. Quantification of apoptotic DNA fragmentation in a transformed uterine epithelial cell line, HRE-H9, using capillary electrophoresis with laser-induced fluorescence detector (CE-LIF).

    Science.gov (United States)

    Fiscus, R R; Leung, C P; Yuen, J P; Chan, H C

    2001-01-01

    Apoptotic cell death of uterine epithelial cells is thought to play an important role in the onset of menstruation and the successful implantation of an embryo during early pregnancy. Abnormal apoptosis in these cells can result in dysmenorrhoea and infertility. In addition, decreased rate of epithelial apoptosis likely contributes to endometriosis. A key step in the onset of apoptosis in these cells is cleavage of the genomic DNA between nucleosomes, resulting in polynucleosomal-sized fragments of DNA. The conventional technique for assessing apoptotic DNA fragmentation uses agarose (slab) gel electrophoresis (i.e. DNA laddering). However, recent technological advances in the use of capillary electrophoresis (CE), particularly the introduction of the laser-induced fluorescence detector (LIF), has made it possible to perform DNA laddering with improved automation and much greater sensitivity. In the present study, we have further developed the CE-LIF technique by using a DNA standard curve to quantify accurately the amount of DNA in the apoptotic DNA fragments and have applied this new quantitative technique to study apoptosis in a transformed uterine epithelial cell line, the HRE-H9 cells. Apoptosis was induced in the HRE-H9 cells by serum deprivation for 5, 7 and 24 h, resulting in increased DNA fragmentation of 2.2-, 3.1- and 6.2-fold, respectively, above the 0 h or plus-serum controls. This ultrasensitive CE-LIF technique provides a novel method for accurately measuring the actions of pro- or anti-apoptotic agents or conditions on uterine epithelial cell lines. Copyright 2001 Academic Press.

  16. Ultratrace analysis of transuranic actinides by laser-induced fluorescence

    Science.gov (United States)

    Miller, S.M.

    1983-10-31

    Ultratrace quantities of transuranic actinides are detected indirectly by their effect on the fluorescent emissions of a preselected fluorescent species. Transuranic actinides in a sample are coprecipitated with a host lattice material containing at least one preselected fluorescent species. The actinide either quenches or enhances the laser-induced fluorescence of the preselected fluorescent species. The degree of enhancement or quenching is quantitatively related to the concentration of actinide in the sample.

  17. Remote sensing vegetation status by laser-induced fluorescence

    International Nuclear Information System (INIS)

    Günther, K.P.; Dahn, H.G.; Lüdeker, W.

    1994-01-01

    In November 1989 the EUREKA project LASFLEUR (EU 380) started as an European research effort to investigate the future application of far-field laser-induced plant fluorescence for synoptic, airborne environmental monitoring of vegetation. This report includes a brief introduction in a theoretically approach for the laser-induced fluorescence signals of leaves and their spectral and radiometric behaviour. In addition, a detailed description of the design and realization of the second generation of the far-field fluorescence lidar (DLidaR-2) is given with special regard to the optical and electronical setup, followed by a short explanation of the data processing. The main objectives of the far field measurements are to demonstrate the link between laser-induced fluorescence data and plant physiology and to show the reliability of remote single shot lidar measurements. The data sets include the typical daily cycles of the fluorescence for different global irradiation. As expected from biophysical models, the remotely sensed chlorophyll fluorescence is highly correlated with the carbon fixation rate, while the fluorescence ratio F685 / F730 is only dependent on the chlorophyll concentration. Drought stress measurement of evergreen oaks Quercus pubescens confirm the findings of healthy plants with regard to the fluorescence ratio F685 / F730 while the fluorescence signals of stressed plants show a different behavior than nonstressed plants. Additionally, the corresponding physiological data (porometer and PAM data) are presented. (author)

  18. Laser-induced fluorescence of oral mucosa cancer

    Science.gov (United States)

    Jaliashvili, Z. V.; Medoidze, T. D.; Melikishvili, Z. G.; Gogilashvili, K. T.

    2017-10-01

    The laser-induced fluorescence (LIF) spectra have been measured for cancer-infused and control mice mucosa tissues. It was established that there is quite a difference between their LIF spectral shapes. These spectral shapes are used to express the diagnostic of different states of tissues: from normal to cancer.

  19. Laser Induced Fluorescence of Helium Ions in a Helicon Plasma

    Science.gov (United States)

    Compton, C. S.; Biloui, C.; Hardin, R. A.; Keesee, A. M.; Scime, E. E.; Boivin, R.

    2003-10-01

    The lack of a suitable Laser Induced Fluorescence (LIF) scheme for helium ions at visible wavelengths has prevented LIF from being employed in helium plasmas for measurements of ion temperature and bulk ion flow speeds. In this work, we will discuss our attempts to perform LIF of helium ions in a helicon source plasma using an infrared, tunable diode laser operating at 1012.36 nm. The infrared transition corresponds to excitation from the n = 4 level (4f ^2F) to the n = 5 (5g ^2G) level of singly ionized helium and therefore requires substantial electron temperatures (> 10 eV) to maintain an adequate ion population in the n = 4 state. Calculations using a steady state coronal model predict that the n = 4 state population will be 25% larger than the n = 5 population for our experimental conditions. The fluorescence decay from the n = 5 (5f ^2F) level of singly ionized helium level to the n = 3 (3d ^2D) level at 320.31 nm is monitored as the diode laser is swept through 10 GHz around the 1012.36 nm line. Note that the fluorescence emission requires a collisionally coupled transition between two different n = 5 quantum states. We will also present measurements of the emission intensities of both the 1012.36 nm and the 320.31 nm lines as a function of source neutral pressure, rf power, and plasma density. This work supported by the U.S. DoE EPSCoR Lab Partnership Program.

  20. Laser induced fluorescence of biochemical for UV LIDAR application.

    Science.gov (United States)

    Gupta, L; Sharma, R C; Razdan, A K; Maini, A K

    2014-05-01

    Laser induced fluorescence spectroscopy in the ultraviolet regime has been used for the detection of biochemical through a fiber coupled CCD detector from a distance of 2 m. The effect of concentration and laser excitation energy on the fluorescence spectra of nicotinamide adenine dinucleotide (NADH) has been investigated. The signature fluorescence peak of NADH was centred about 460 nm. At lower concentration Raman peak centred at 405 nm was also observed. The origin of this peak has been discussed. Detection limit with the proposed set up is found to be 1 ppm.

  1. Time-synchronized continuous wave laser-induced fluorescence on an oscillatory xenon discharge.

    Science.gov (United States)

    MacDonald, N A; Cappelli, M A; Hargus, W A

    2012-11-01

    A novel approach to time-synchronizing laser-induced fluorescence measurements to an oscillating current in a 60 Hz xenon discharge lamp using a continuous wave laser is presented. A sample-hold circuit is implemented to separate out signals at different phases along a current cycle, and is followed by a lock-in amplifier to pull out the resulting time-synchronized fluorescence trace from the large background signal. The time evolution of lower state population is derived from the changes in intensity of the fluorescence excitation line shape resulting from laser-induced fluorescence measurements of the 6s(')[1/2](1)(0)-6p(')[3/2](2) xenon atomic transition at λ = 834.68 nm. Results show that the lower state population oscillates at twice the frequency of the discharge current, 120 Hz.

  2. Time-synchronized continuous wave laser-induced fluorescence on an oscillatory xenon discharge

    Energy Technology Data Exchange (ETDEWEB)

    MacDonald, N. A.; Cappelli, M. A. [Stanford Plasma Physics Laboratory, Stanford University, Stanford, California 94305 (United States); Hargus, W. A. Jr. [Air Force Research Laboratory, Edwards AFB, California 93524 (United States)

    2012-11-15

    A novel approach to time-synchronizing laser-induced fluorescence measurements to an oscillating current in a 60 Hz xenon discharge lamp using a continuous wave laser is presented. A sample-hold circuit is implemented to separate out signals at different phases along a current cycle, and is followed by a lock-in amplifier to pull out the resulting time-synchronized fluorescence trace from the large background signal. The time evolution of lower state population is derived from the changes in intensity of the fluorescence excitation line shape resulting from laser-induced fluorescence measurements of the 6s{sup Prime }[1/2]{sub 1}{sup 0}-6p{sup Prime }[3/2]{sub 2} xenon atomic transition at {lambda}= 834.68 nm. Results show that the lower state population oscillates at twice the frequency of the discharge current, 120 Hz.

  3. Estimating Chlorophyll Fluorescence Parameters Using the Joint Fraunhofer Line Depth and Laser-Induced Saturation Pulse (FLD-LISP Method in Different Plant Species

    Directory of Open Access Journals (Sweden)

    Parinaz Rahimzadeh-Bajgiran

    2017-06-01

    Full Text Available A comprehensive evaluation of the recently developed Fraunhofer line depth (FLD and laser-induced saturation pulse (FLD-LISP method was conducted to measure chlorophyll fluorescence (ChlF parameters of the quantum yield of photosystem II (ΦPSII, non-photochemical quenching (NPQ, and the photosystem II-based electron transport rate (ETR in three plant species including paprika (C3 plant, maize (C4 plant, and pachira (C3 plant. First, the relationships between photosynthetic photon flux density (PPFD and ChlF parameters retrieved using FLD-LISP and the pulse amplitude-modulated (PAM methods were analyzed for all three species. Then the relationships between ChlF parameters measured using FLD-LISP and PAM were evaluated for the plants in different growth stages of leaves from mature to aging conditions. The relationships of ChlF parameters/PPFD were similar in both FLD-LISP and PAM methods in all plant species. ΦPSII showed a linear relationship with PPFD in all three species whereas NPQ was found to be linearly related to PPFD in paprika and maize, but not for pachira. The ETR/PPFD relationship was nonlinear with increasing values observed for PPFDs lower than about 800 μmol m−2 s−1 for paprika, lower than about 1200 μmol m−2 s−1 for maize, and lower than about 800 μmol m−2 s−1 for pachira. The ΦPSII, NPQ, and ETR of both the FLD-LISP and PAM methods were very well correlated (R2 = 0.89, RMSE = 0.05, (R2 = 0.86, RMSE = 0.44, and (R2 = 0.88, RMSE = 24.69, respectively, for all plants. Therefore, the FLD-LISP method can be recommended as a robust technique for the estimation of ChlF parameters.

  4. Impurity monitoring by laser-induced fluorescence techniques

    International Nuclear Information System (INIS)

    Gelbwachs, J.A.

    1984-01-01

    Laser-induced fluorescence spectroscopy can provide a highly sensitive and selective means of detecting atomic and ionic impurities. Because the photodetector can be physically isolated from the laser-excited region, these techniques can be applied to monitoring in hostile environments. The basic concepts behind fluorescence detection are reviewed. Saturated optical excitation is shown to maximize impurity atom emission yield while mitigating effects of laser intensity fluctuations upon absolute density calibration. Monitoring in high- and low-pressure monitoring environments is compared. Methods to improve detection sensitivity by luminescence background suppression are presented

  5. Characterisation of estuarine intertidal macroalgae by laser-induced fluorescence

    DEFF Research Database (Denmark)

    Gameiro, Carla; Utkin, Andrei B.; Sousa Dias Cartaxana, Paulo Jorge

    2015-01-01

    The article reports the application of laser-induced fluorescence (LIF) for the assessment of macroalgae communities of estuarine intertidal areas. The method was applied for the characterisation of fifteen intertidal macroalgae species of the Tagus estuary, Portugal, and adjacent coastal area...... spectra were determined by differences in the main fluorescing pigments: phycoerythrin, phycocyanin and chlorophyll a (Chl a). In the green and brown macroalgae groups, the relative significance of the two emission maxima seems to be related to the thickness of the photosynthetic layer. In thick...... macroalgae, like Codium tomentosum or Fucus vesiculosus, the contribution of the far-red emission fluorescence peak was more significant, most probably due to re-absorption of the emitted red Chl a fluorescence within the dense photosynthetic layer. Similarly, an increase in the number of layers of the thin...

  6. Kr II laser-induced fluorescence for measuring plasma acceleration.

    Science.gov (United States)

    Hargus, W A; Azarnia, G M; Nakles, M R

    2012-10-01

    We present the application of laser-induced fluorescence of singly ionized krypton as a diagnostic technique for quantifying the electrostatic acceleration within the discharge of a laboratory cross-field plasma accelerator also known as a Hall effect thruster, which has heritage as spacecraft propulsion. The 728.98 nm Kr II transition from the metastable 5d(4)D(7/2) to the 5p(4)P(5/2)(∘) state was used for the measurement of laser-induced fluorescence within the plasma discharge. From these measurements, it is possible to measure velocity as krypton ions are accelerated from near rest to approximately 21 km/s (190 eV). Ion temperature and the ion velocity distributions may also be extracted from the fluorescence data since available hyperfine splitting data allow for the Kr II 5d(4)D(7/2)-5p(4)P(5/2)(∘) transition lineshape to be modeled. From the analysis, the fluorescence lineshape appears to be a reasonable estimate for the relatively broad ion velocity distributions. However, due to an apparent overlap of the ion creation and acceleration regions within the discharge, the distributed velocity distributions increase ion temperature determination uncertainty significantly. Using the most probable ion velocity as a representative, or characteristic, measure of the ion acceleration, overall propellant energy deposition, and effective electric fields may be calculated. With this diagnostic technique, it is possible to nonintrusively characterize the ion acceleration both within the discharge and in the plume.

  7. Time-resolved laser-induced fluorescence system

    Science.gov (United States)

    Bautista, F. J.; De la Rosa, J.; Gallegos, F. J.

    2006-02-01

    Fluorescence methods are being used increasingly in the measurement of species concentrations in gases, liquids and solids. Laser induced fluorescence is spontaneous emission from atoms or molecules that have been excited by laser radiation. Here we present a time resolved fluorescence instrument that consists of a 5 μJ Nitrogen laser (337.1 nm), a sample holder, a quartz optical fiber, a spectrometer, a PMT and a PC that allows the measurement of visible fluorescence spectra (350-750 nm). Time response of the system is approximately 5 ns. The instrument has been used in the measurement of colored bond paper, antifreeze, diesel, cochineal pigment and malignant tissues. The data acquisition was achieved through computer control of a digital oscilloscope (using General Purpose Interface Bus GPIB) and the spectrometer via serial (RS232). The instrument software provides a graphic interface that lets make some data acquisition tasks like finding fluorescence spectra, and fluorescence lifetimes. The software was developed using the Lab-View 6i graphic programming package and can be easily managed in order to add more functions to it.

  8. Laser-induced fluorescence in the detection of esophageal carcinoma

    Science.gov (United States)

    Wang, Kenneth K.; Gutta, Kumar; Laukka, Mark A.; Densmore, John

    1995-01-01

    Laser induced fluorescence (LIF) is a technique which can perform an 'optical biopsy' of gastrointestinal mucosa. LIF was performed in resected specimens using a pulsed N2-laser coupled fiberoptically to a probe. Fluorescence was measured using a 0.2 meter spectroscope with an intensified photodiode array. Measurements were made on fresh (esophagus, and adenocarcinoma. Each tissue section was examined using an optical probe consisting of a central fiber for delivering the excitation energy and a 6 fiber bundle surrounding the central fiber for detection of the fluorescence. An excitation wavelength of 337 nm was used which generated 3-ns pulses while fluorescence intensities were acquired from 300-800 nm. Spectra were obtained from each section in a standardized fashion and background spectra subtracted. Fluorescence readings were taken from 54 normal esophageal sections and 32 sections of adenocarcinoma. A fluorescence index obtained from the tumor sections was 0.68+/- 0.01 compared with 0.51+/- 0.01 for the normal sections (pesophagus with good accuracy.

  9. Simulating fluorescence light-canopy interaction in support of laser-induced fluorescence measurements

    International Nuclear Information System (INIS)

    Rosema, A.; Verhoef, W.; Schroote, J.; Snel, J.F.H.

    1991-01-01

    In the Netherlands an operational field instrument for the measurement of laser induced fluorescence of vegetation (LEAF) is developed. In addition, plant physiological and remote sensing research is done to support this new remote sensing instrument. This paper presents a general introduction on the subject of laser-induced fluorescence, including the relation between chlorophyll fluorescence and photosynthesis, spectral characteristics, and previous research. Also the LEAF system is briefly described. Subsequently, the development of a leaf fluorescence model (KMF) and a canopy fluorescence model (FLSAIL) are reported. With these simulation models a sensitivity study is carried out. Fluorescence of 685 nm appears to be most suitable to obtain information on photosynthesis and stress, but is also influenced by canopy structure. Separation of these two effects is studied

  10. Detection of vegetation stress from laser-induced fluorescence signatures

    International Nuclear Information System (INIS)

    Subhash, N.

    1995-01-01

    The in vivo laser-induced fluorescence (LIF) signatures of UV irradiated Salvia splendens plants were measured using an Optical Multichannel Analyser (OMA) system with Nitrogen laser excitation. The LIF spectra which consisted of the blue-green and the red chlorophyll bands were analysed with a non-linear interactive procedure using Gaussian spectral functions. The fluorescence intensity ratios of the various bands obtained from curve fitted parameters were found to be more sensitive to changes in the photosynthetic activity of the plant. The variation in the intensity ratio for the chlorophyll bands for nutrient stressed sunflower, cotton and groundnut plants as well as the nutrient and water stressed rice plants are also presented. It is observed that vegetation stress not only changes the fluorescence intensity ratios and the vitality index of the plant but also changes the peak position of the emission bands, in some cases. It is also seen that analysis of the fluorescence spectra in vegetation remote sensing applications would require a deconvolution procedure to evaluate the exact contribution of each band in the total spectra. (author). 23 refs, 8 figs, 5 tabs

  11. Sputtering of amorphous carbon layers studied by laser induced fluorescence

    International Nuclear Information System (INIS)

    Pasch, E.

    1992-07-01

    In order to minimize the radiation losses, it is desirable to keep the plasmas in nuclear fusion devices free of high-Z-impurities. Therefore, the walls of TEXTOR and other tokamaks are covered with thin layers of amorphous carbon layers (a-C:H) or amorphous carbon/boron layers (a-C/B:H). The sputtering behaviour of these layers has been studied under bombardment by Ar + ions with energies of 1.5 keV and current densities of a few mA/cm 2 . Investigations of these coatings were carried out with the object to measure the velocity distribution of the sputtered atoms and the sputtered yields by laser induced fluorescence in the vacuum ultraviolet. (orig.)

  12. Design of remote laser-induced fluorescence system's acquisition circuit

    Science.gov (United States)

    Wang, Guoqing; Lou, Yue; Wang, Ran; Yan, Debao; Li, Xin; Zhao, Xin; Chen, Dong; Zhao, Qi

    2017-10-01

    Laser-induced fluorescence system(LIfS) has been found its significant application in identifying one kind of substance from another by its properties even it's thimbleful, and becomes useful in plenty of fields. Many superior works have reported LIfS' theoretical analysis , designs and uses. However, the usual LIPS is always constructed in labs to detect matter quite closely, for the system using low-power laser as excitation source and charge coupled device (CCD) as detector. Promoting the detectivity of LIfS is of much concern to spread its application. Here, we take a high-energy narrow-pulse laser instead of commonly used continuous wave laser to operate sample, thus we can get strong fluorescent. Besides, photomultiplier (PMT) with high sensitivity is adopted in our system to detect extremely weak fluorescence after a long flight time from the sample to the detector. Another advantage in our system, as the fluorescence collected into spectroscopy, multiple wavelengths of light can be converted to the corresponding electrical signals with the linear array multichannel PMT. Therefore, at the cost of high-powered incentive and high-sensitive detector, a remote LIFS is get. In order to run this system, it is of importance to turn light signal to digital signal which can be processed by computer. The pulse width of fluorescence is deeply associated with excitation laser, at the nanosecond(ns) level, which has a high demand for acquisition circuit. We design an acquisition circuit including, I/V conversion circuit, amplifying circuit and peak-holding circuit. The simulation of circuit shows that peak-holding circuit can be one effective approach to reducing difficulty of acquisition circuit.

  13. Study on two-color planar laser induced fluorescence thermometry

    International Nuclear Information System (INIS)

    Li Shaodan; Tan Sichao; Gao Puzhen; Lin Yuansheng

    2014-01-01

    Many of the convection heat transfer process are involved in the research of nuclear reactor thermal hydraulics. To experimentally determine the variation of the temperature field in those processes is important for the design and safety operation of the nuclear reactor. The application of the two-color planar laser induced fluorescence (PLIF) in the measurements of fluid temperature distribution is discussed in the paper. The laser dyes used here is rhodamine B (RhB) with negative temperature coefficient and fluorescein 27 (F127) with positive temperature coefficient. The beam of the laser light is adjusted to laser sheet by using the lens group. The fluid with dyes is excited by this laser sheet in a specific plane and temperature dependent fluorescence is released. The temperature field of the plane can be determined through the intensity information. Some technical aspects encountered in the application of the two-laser PLIF are discussed in the paper, such as the spectra characteristic of the dyes and the separation of the spectra. The calibration temperature is higher than the water saturation temperature (at atmosphere pressure). (authors)

  14. Laser-induced fluorescence detection strategies for sodium atoms and compounds in high-pressure combustors

    Science.gov (United States)

    Weiland, Karen J. R.; Wise, Michael L.; Smith, Gregory P.

    1993-01-01

    A variety of laser-induced fluorescence schemes were examined experimentally in atmospheric pressure flames to determine their use for sodium atom and salt detection in high-pressure, optically thick environments. Collisional energy transfer plays a large role in fluorescence detection. Optimum sensitivity, at the parts in 10 exp 9 level for a single laser pulse, was obtained with the excitation of the 4p-3s transition at 330 nm and the detection of the 3d-3p fluorescence at 818 nm. Fluorescence loss processes, such as ionization and amplified spontaneous emission, were examined. A new laser-induced atomization/laser-induced fluorescence detection technique was demonstrated for NaOH and NaCl. A 248-nm excimer laser photodissociates the salt molecules present in the seeded flames prior to atom detection by laser-induced fluorescence.

  15. Time-resolved resonance fluorescence spectroscopy for study of chemical reactions in laser-induced plasmas.

    Science.gov (United States)

    Liu, Lei; Deng, Leimin; Fan, Lisha; Huang, Xi; Lu, Yao; Shen, Xiaokang; Jiang, Lan; Silvain, Jean-François; Lu, Yongfeng

    2017-10-30

    Identification of chemical intermediates and study of chemical reaction pathways and mechanisms in laser-induced plasmas are important for laser-ablated applications. Laser-induced breakdown spectroscopy (LIBS), as a promising spectroscopic technique, is efficient for elemental analyses but can only provide limited information about chemical products in laser-induced plasmas. In this work, time-resolved resonance fluorescence spectroscopy was studied as a promising tool for the study of chemical reactions in laser-induced plasmas. Resonance fluorescence excitation of diatomic aluminum monoxide (AlO) and triatomic dialuminum monoxide (Al 2 O) was used to identify these chemical intermediates. Time-resolved fluorescence spectra of AlO and Al 2 O were used to observe the temporal evolution in laser-induced Al plasmas and to study their formation in the Al-O 2 chemistry in air.

  16. The motional stark effect with laser-induced fluorescence diagnostic

    Science.gov (United States)

    Foley, E. L.; Levinton, F. M.

    2010-05-01

    The motional Stark effect (MSE) diagnostic is the worldwide standard technique for internal magnetic field pitch angle measurements in magnetized plasmas. Traditionally, it is based on using polarimetry to measure the polarization direction of light emitted from a hydrogenic species in a neutral beam. As the beam passes through the magnetized plasma at a high velocity, in its rest frame it perceives a Lorentz electric field. This field causes the H-alpha emission to be split and polarized. A new technique under development adds laser-induced fluorescence (LIF) to a diagnostic neutral beam (DNB) for an MSE measurement that will enable radially resolved magnetic field magnitude as well as pitch angle measurements in even low-field (experiments. An MSE-LIF system will be installed on the National Spherical Torus Experiment (NSTX) at the Princeton Plasma Physics Laboratory. It will enable reconstructions of the plasma pressure, q-profile and current as well as, in conjunction with the existing MSE system, measurements of radial electric fields.

  17. In-situ hydrocarbon delineation using laser-induced fluorescence

    International Nuclear Information System (INIS)

    Taer, A.D.; Hastings, R.W.; Brown, A.Y.; Frend, R.

    1996-01-01

    An investigation of hydrocarbons in soils was conducted at an active Shell Oil Company petroleum products terminal, located in Carson, California. An investigation approach involving Laser-Induced Fluorescence (LIF) and Cone Penetrometer Testing (CPT) technologies was implemented to provide real-time, in-situ characterization of site stratigraphy, hydrocarbon distribution and importantly, hydrocarbon product differentiation. The area of investigation is located along a property boundary, where a plume of separate phase hydrocarbons has been actively recovered for several years. CPT/LIF technology was selected for the investigation since previous delineation efforts using hydrocarbon fingerprinting methods proved inconclusive. Additionally, the CPT/LIF technology had the potential to provide a cost effective solution to accomplish project objectives. Based on the information obtained during this investigation, it was determined that the plume of separate phase hydrocarbons along the northern property boundary is from a source distinctly different than any identified hydrocarbons known to be from on-site sources. In addition, the plume was determined to not be connected with any other known on-site hydrocarbon plumes. The results of this CPT/LIF investigation were consistent with the known hydrogeologic conditions. This evaluation determined that CPT/LIF technology was very effective in addressing project objectives and resulted in a significant cost savings

  18. Airborne laser induced fluorescence imaging. Innovative technology summary report

    International Nuclear Information System (INIS)

    1999-06-01

    Laser-Induced Fluorescence (LIF) was demonstration as part of the Fernald Environmental Management Project (FEMP) Plant 1 Large Scale Demonstration and Deployment Project (LSDDP) sponsored by the US Department of Energy (DOE) Office of Science and Technology, Deactivation and Decommissioning Focus Area located at the Federal Energy Technology Center (FETC) in Morgantown, West Virginia. The demonstration took place on November 19, 1996. In order to allow the contaminated buildings undergoing deactivation and decommissioning (D and D) to be opened to the atmosphere, radiological surveys of floors, walls and ceilings must take place. After successful completion of the radiological clearance survey, demolition of the building can continue. Currently, this process is performed by collecting and analyzing swipe samples for radiological analysis. Two methods are used to analyze the swipe samples: hand-held frisker and laboratory analysis. For the purpose of this demonstration, the least expensive method, swipe samples analyzed by hand-held frisker, is the baseline technology. The objective of the technology demonstration was to determine if the baseline technology could be replaced using LIF

  19. Laser Induced Fluorescence Diagnostic for the Plasma Couette Experiment

    Science.gov (United States)

    Katz, Noam; Skiff, Fred; Collins, Cami; Weisberg, Dave; Wallace, John; Clark, Mike; Garot, Kristine; Forest, Cary

    2010-11-01

    The Plasma Couette Experiment (PCX) at U. Wisconsin-Madison consists of a rotating high-beta plasma and is well-suited to the study of flow-driven, astrophysically-relevant plasma phenomena. PCX confinement relies on alternating rings of 1kG permanent magnets and the rotation is driven by electrode rings, interspersed between the magnets, which provide an azimuthal ExB. I will discuss the development of a laser-induced fluorescence diagnostic (LIF) to characterize the ion distribution function of argon plasmas in PCX. The LIF system--which will be scanned radially--will be used to calibrate internal Mach probes, as well as to measure the time-resolved velocity profile, ion temperature and density non-perturbatively. These diagnostics will be applied to study the magneto-rotational instability in a plasma, as well as the buoyancy instability thought to be involved in producing the solar magnetic field. This work is supported by NSF and DOE.

  20. Femtosecond two-photon laser-induced fluorescence of krypton for high-speed flow imaging.

    Science.gov (United States)

    Wang, Yejun; Capps, Cade; Kulatilaka, Waruna D

    2017-02-15

    Ultrashort-pulse (femtosecond-duration) two-photon laser-induced fluorescence (fs-TPLIF) of an inert gas tracer krypton (Kr) is investigated. A detailed spectroscopic study of fluorescence channels followed by the 5p'←←4p excitation of Kr at 204.1 nm is reported. The experimental line positions in the 750-840 nm emission region agree well with the NIST Atomic Spectra Database. The present work provides an accurate listing of relative line strengths in this spectral region. In the range of laser pulse energies investigated, a quadratic dependence was observed between the Kr-TPLIF signal and the laser pulse energy. The single-laser-shot 2D TPLIF images recorded in an unsteady jet demonstrate the potential of using fs excitation at 204.1 nm for mixing and flow diagnostic studies using Kr as an inert gas tracer.

  1. Laser-Induced Fluorescence diagnostic of barium ion plasmas in the Paul Trap Simulator Experiment

    International Nuclear Information System (INIS)

    Chung, Moses; Gilson, Erik P.; Davidson, Ronald C.; Efthimion, Philip C.; Majeski, Richard; Startsev, Edward A.

    2005-01-01

    The Paul Trap Simulator Experiment (PTSX) is a cylindrical Paul trap whose purpose is to simulate the nonlinear dynamics of intense charged particle beam propagation in alternating-gradient magnetic transport systems. To investigate the ion plasma microstate in PTSX, including the ion density profile and the ion velocity distribution function, a laser-induced fluorescence diagnostic system is being developed as a nondestructive diagnostic. Instead of cesium, which has been used in the initial phase of the PTSX experiment, barium has been selected as the preferred ion for the laser-induced fluorescence diagnostic. A feasibility study of the laser-induced fluorescence diagnostic using barium ions is presented with the characterization of a tunable dye laser. The installation of the barium ion source and the development of the laser-induced fluorescence diagnostic system are also discussed

  2. Laser-Induced Fluorescence Measurements within a Laboratory Hall Thruster (Postprint)

    National Research Council Canada - National Science Library

    Hargus, Jr., W. A; Cappelli, M. A

    1999-01-01

    In this paper, we describe the results of a study of laser induced fluorescence velocimetry of ionic xenon in the plume and interior acceleration channel of a laboratory Hall type thruster operating...

  3. Quantitative laser-induced fluorescence measurements of nitric oxide in a heavy-duty Diesel engine

    NARCIS (Netherlands)

    Verbiezen, K.; Klein-Douwel, R. J. H.; van Viet, A. P.; Donkerbroek, A. J.; Meerts, W. L.; Dam, N. J.; ter Meulen, J. J.

    2007-01-01

    We present quantitative, in-cylinder, UV-laser-induced fluorescence measurements of nitric oxide in a heavy-duty Diesel engine. Processing of the raw fluorescence signals includes a detailed correction, based on additional measurements, for the effect of laser beam and fluorescence attenuation, and

  4. Laser-Induced Photofragmentation Fluorescence Imaging of Alkali Compounds in Flames.

    Science.gov (United States)

    Leffler, Tomas; Brackmann, Christian; Aldén, Marcus; Li, Zhongshan

    2017-06-01

    Laser-induced photofragmentation fluorescence has been investigated for the imaging of alkali compounds in premixed laminar methane-air flames. An ArF excimer laser, providing pulses of wavelength 193 nm, was used to photodissociate KCl, KOH, and NaCl molecules in the post-flame region and fluorescence from the excited atomic alkali fragment was detected. Fluorescence emission spectra showed distinct lines of the alkali atoms allowing for efficient background filtering. Temperature data from Rayleigh scattering measurements together with simulations of potassium chemistry presented in literature allowed for conclusions on the relative contributions of potassium species KOH and KCl to the detected signal. Experimental approaches for separate measurements of these components are discussed. Signal power dependence and calculated fractions of dissociated molecules indicate the saturation of the photolysis process, independent on absorption cross-section, under the experimental conditions. Quantitative KCl concentrations up to 30 parts per million (ppm) were evaluated from the fluorescence data and showed good agreement with results from ultraviolet absorption measurements. Detection limits for KCl photofragmentation fluorescence imaging of 0.5 and 1.0 ppm were determined for averaged and single-shot data, respectively. Moreover, simultaneous imaging of KCl and NaCl was demonstrated using a stereoscope with filters. The results indicate that the photofragmentation method can be employed for detailed studies of alkali chemistry in laboratory flames for validation of chemical kinetic mechanisms crucial for efficient biomass fuel utilization.

  5. Single-Shot, Volumetrically Illuminated, Three-Dimensional, Tomographic Laser-Induced-Fluorescence Imaging in a Gaseous Free Jet

    Science.gov (United States)

    2016-04-28

    Single-shot, volumetrically illuminated, three- dimensional, tomographic laser-induced- fluorescence imaging in a gaseous free jet Benjamin R. Halls...acquisition; (110.6955) Tomographic imaging ; (110.6960) Tomography; (280.2490) Flow diagnostics; (300.2530) Fluorescence , laser-induced...84 (1983). 2. I. van Cruyningen, A. Lozano, and R. K. Hanson, “Quantitative imaging of concentration by planar laser-induced fluorescence ,” Exp

  6. Laser induced fluorescence measurements of the mixing of fuel oil with air

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, A; Bombach, R; Hubschmid, W; Kaeppeli, B [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    We report on measurements of the mixing of fuel oil with air at atmospheric pressure in an industrial premixed gas turbine burner. The concentration of the vaporized fuel oil was measured with laser induced fluorescence. We reason that the fuel oil concentration can be considered with good accuracy as proportional to the fluorescence intensity. (author) 6 fig., 3 refs.

  7. Detection of fecal residue on poultry carcasses by laser induced fluorescence imaging techniques

    Science.gov (United States)

    The potential use of laser-induced fluorescence imaging techniques was investigated for the detection of diluted fecal matters from various parts of the digestive tract, including colon, ceca, small intestine, and duodenum, on poultry carcasses. One of the challenges for using fluorescence imaging f...

  8. Recognition of edible oil by using BP neural network and laser induced fluorescence spectrum

    Science.gov (United States)

    Mu, Tao-tao; Chen, Si-ying; Zhang, Yin-chao; Guo, Pan; Chen, He; Zhang, Hong-yan; Liu, Xiao-hua; Wang, Yuan; Bu, Zhi-chao

    2013-09-01

    In order to accomplish recognition of the different edible oil we set up a laser induced fluorescence spectrum system in the laboratory based on Laser induced fluorescence spectrum technology, and then collect the fluorescence spectrum of different edible oil by using that system. Based on this, we set up a fluorescence spectrum database of different cooking oil. It is clear that there are three main peak position of different edible oil from fluorescence spectrum chart. Although the peak positions of all cooking oil were almost the same, the relative intensity of different edible oils was totally different. So it could easily accomplish that oil recognition could take advantage of the difference of relative intensity. Feature invariants were extracted from the spectrum data, which were chosen from the fluorescence spectrum database randomly, before distinguishing different cooking oil. Then back propagation (BP) neural network was established and trained by the chosen data from the spectrum database. On that basis real experiment data was identified by BP neural network. It was found that the overall recognition rate could reach as high as 83.2%. Experiments showed that the laser induced fluorescence spectrum of different cooking oil was very different from each other, which could be used to accomplish the oil recognition. Laser induced fluorescence spectrum technology, combined BP neural network,was fast, high sensitivity, non-contact, and high recognition rate. It could become a new technique to accomplish the edible oil recognition and quality detection.

  9. Laser-induced fluorescence spectra of Ba+*-He exciplexes produced in cold He gas

    International Nuclear Information System (INIS)

    Fukuyama, Yoshimitsu; Matsuo, Yukari; Moriwaki, Yoshiki

    2004-01-01

    We report the observation of laser-induced fluorescence spectra of Ba +* -He exciplexes. The experiment is carried out in an environment of cold gaseous helium at a temperature range of 3-30 K. We have observed the emission spectra of exciplexes by means of excitation of the 6p 2 P 32 2 S 12 transition of Ba + ions. It is found that these spectra are redshifted from the D2 emission line in the free space and are composed of several peaks. The experimental results are reproduced well by theoretical calculation of the emission spectra for vibrational levels of Ba +* -He. We also investigate the vibrational dynamics of the 6p 2 Π 32 state of Ba + *-He, and we have determined the collision-induced vibrational relaxation cross sections of the 6p 2 Π 32 state to be 9.7±1.1 A 2 at 15 K

  10. Development of Laser-Induced Fluorescence Diagnostic for the Paul Trap Simulator Experiment

    CERN Document Server

    Chung, Moses; Efthimion, Philip; Gilson, Erik P; Majeski, Richard; Startsev, Edward

    2005-01-01

    The Paul Trap Simulator Experiment (PTSX) is a cylindrical Paul trap whose purpose is to simulate the nonlinear dynamics of intense charged particle beam propagation in alternating-gradient magnetic transport systems. For the in-situ measurement of the transverse ion density profile in the PTSX device, which is essential for the study of beam mismatch and halo particle production, a laser-induced fluorescence diagnostic system is being developed. Instead of cesium, which has been used in the initial phase of the PTSX experiment, barium has been selected as the preferred ion for the laser-induced fluorescence diagnostic. The installation of the barium ion source and the characterization of the tunable dye laser system are discussed. The design of the collection optics with an intensified CCD camera system is also discussed. Finally, initial test results using the laser-induced fluorescence diagnostic will be presented.

  11. Laser-induced fluorescence of se, as, and sb in an electrothermal atomizer.

    Science.gov (United States)

    Swart, D J; Ezer, M; Pacquette, H L; Simeonsson, J B

    1998-04-01

    Trace detection of Se, As, and Sb atoms has been performed by electrothermal atomization laser-induced fluorescence (ETA-LIF) approaches. Production of far-UV radiation necessary for excitation of As atoms at 193.696 nm and Se atoms at 196.026 nm was accomplished by stimulated Raman shifting (SRS) of the output of a frequency-doubled dye laser operating near 230 nm. Both wavelengths were obtained as second-order anti-Stokes shifts of the dye laser radiation and provided up to 10 μJ/pulse, which was shown through power dependence studies to be sufficient for saturation in the ETA. An excited-state direct line fluorescence approach using excitation at 206.279 nm was also investigated for the LIF detection of Se. High-sensitivity LIF of Sb atoms was accomplished using 206.833-nm excitation and detection at 259.805 nm. The accuracy of the ETA-LIF approaches was demonstrated by determining the As and Se content of aqueous reference samples. The limits of detection (absolute mass) were 200 fg by ground-state LIF and 150 fg by excited-state direct line fluorescence for Se, 200 fg for As, and 10 fg for Sb; these LODs compare favorably with results reported previously in the literature for ETA-LIF, GFAAS, and ICP-MS methods.

  12. In vivo study of the human skin by the method of laser-induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Borisova, E.; Avramov, L.

    2000-01-01

    The goals of this study are to perform a preliminary evaluation of the diagnostic potential of noninvasive laser-induced auto-fluorescence spectroscopy (LIAFS) for human skin and optimize of detection and diagnosis of hollow organs and skin. In recent years, there has been growing interest in the use of laser-induced fluorescence to discriminate disease from normal surrounding tissue. The most fluorescence studies have used exogenous fluorophores of this discrimination. The laser-induced auto-fluorescence which is used for diagnosis of tissues in the human body avoids administration of any drugs. In this study a technique for optical biopsy of in vivo human skin is presented. The auto-fluorescence characterization of tissue relies on different spectral properties of tissues. It was demonstrated a differentiation between normal skin and skin with vitiligo. Two main endogenous fluorophores in the human skin account for most of the cellular auto-fluorescence for excitation wavelength 337 nm reduced from of nicotinamide adenine dinucleotide and collagen. The auto-fluorescence spectrum of human skin depend on main internal absorbers which are blood and melanin. In this study was described the effect caused by blood and melanin content on the shape of the auto-fluorescence spectrum of human skin. Human skin fluorescence spectrum might provide dermatologists with important information and such investigations are successfully used now in skin disease diagnostics, in investigation of the environmental factor impact or for evaluation of treatment efficiency. (authors)

  13. Laser-induced fluorescence detection platform for point-of-care testing

    Science.gov (United States)

    Berner, Marcel; Hilbig, Urs; Schubert, Markus B.; Gauglitz, Günter

    2017-08-01

    Point-of-care testing (POCT) devices for continuous low-cost monitoring of critical patient parameters require miniaturized and integrated setups for performing quick high-sensitivity analyses, away from central clinical laboratories. This work presents a novel and promising laser-induced fluorescence platform for measurements in direct optical test formats that leads towards such powerful POCT devices based on fluorescence-labeled immunoassays. Ultimate sensitivity of thin film photodetectors, integrated with microfluidics, and a comprehensive optimization of all system components aim at low-level signal detection in the targeted biosensor application. The setup acquires fluorescence signals from the volume of a microfluidic channel. An innovative sandwiching process forms a flow channel in the microfluidic chips by embedding laser-cut double-sided adhesive tapes. The custom fit of amorphous silicon based photodiode arrays to the geometry of the flow channel enables miniaturization, fully adequate for POCT devices. A free-beam laser excitation with line focus provides excellent alignment stability, allows for easy and reliable swapping of the disposable microfluidic chips, and therewith greatly improves the ease of use of the resulting integrated device. As a proof-of-concept of this novel in-volume measurement approach, the limit of detection for the dye DY636-COOH in pure water as a model fluorophore is examined and found to be 26 nmol l-1 .

  14. [Laser induced fluorescence spectrum characteristics of common edible oil and fried cooking oil].

    Science.gov (United States)

    Mu, Tao-tao; Chen, Si-ying; Zhang, Yin-chao; Chen, He; Guo, Pan; Ge, Xian-ying; Gao, Li-lei

    2013-09-01

    In order to detect the trench oil the authors built a trench oil rapid detection system based on laser induced fluorescence detection technology. This system used 355 nm laser as excitation light source. The authors collected the fluorescence spectrum of a variety of edible oil and fried cooking oil (a kind of trench oil) and then set up a fluorescence spectrum database by taking advantage of the trench oil detection system It was found that the fluorescence characteristics of fried cooking oil and common edible oil were obviously different. Then it could easily realize the oil recognition and trench oil rapid detection by using principal component analysis and BP neural network, and the overall recognition rate could reach as high as 97.5%. Experiments showed that laser induced fluorescence spectrum technology was fast, non-contact, and highly sensitive. Combined with BP neural network, it would become a new technique to detect the trench oil.

  15. Serum Protein Profile Study of Clinical Samples Using High Performance Liquid Chromatography-Laser Induced Fluorescence

    DEFF Research Database (Denmark)

    Karemore, Gopal Raghunath; Ukendt, Sujatha; Rai, Lavanya

    2009-01-01

    The serum protein profiles of normal subjects, patients diagnosed with cervical cancer, and oral cancer were recorded using High Performance Liquid Chromatography combined with Laser Induced Fluorescence detection (HPLC-LIF). Serum protein profiles of the above three classes were tested for estab...

  16. Laser-induced fluorescence of metal-atom impurities in a neutral beam

    International Nuclear Information System (INIS)

    Burrell, C.F.; Pyle, R.V.; Sabetimani, Z.; Schlachter, A.S.

    1984-10-01

    The need to limit impurities in fusion devices to low levels is well known. We have investigated, by the technique of laser-induced fluorescence, the concentration of heavy-metal atoms in a neutral beam caused by their evaporation from the hot filaments in a conventional high-current multifilament hydrogen-ion source

  17. Speciation of actinides in aqueous solution by time-resolved laser-induced fluorescence spectroscopy (TRLFS)

    International Nuclear Information System (INIS)

    Kimura, Takaumi; Kato, Yoshiharu; Meinrath, G.; Yoshida, Zenko; Choppin, G.R.

    1995-01-01

    Time-resolved laser-induced fluorescence spectroscopy (TRLFS) as a sensitive and selective method has been applied to the speciation of actinides in aqueous solution. Studies on hydrolysis and carbonate complexation of U(VI) and on determination of hydration number of Cm(III) are reported. (author)

  18. Pressure broadening of atomic oxygen two-photon absorption laser induced fluorescence

    NARCIS (Netherlands)

    Marinov, D.; Drag, C.; Blondel, C.; Guaitella, O.; Golda, J.; Klarenaar, B.L.M.; Engeln, R.A.H.; Schulz-von der Gathen, V.; Booth, J.-P.

    2016-01-01

    Atomic oxygen, considered to be a determining reactant in plasma applications at ambient pressure, is routinely detected by two-photon absorption laser induced fluorescence (TALIF). Here, pressure broadening of the (2p 4 3 P 2  →  3p 3 P J=0,1,2) two-photon transition in oxygen atoms was

  19. Formation of nitric oxide in an industrial burner measured by 2-D laser induced fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, A; Bombach, R; Kaeppeli, B [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    We have performed two-dimensional Laser Induced Fluorescence (2-D LIF) measurements of nitric oxide and hydroxyl radical distributions in an industrial burner at atmospheric pressure. The relative 2-D LIF data of NO were set to an absolute scale by calibration with probe sampling combined with gas analysis. (author) 3 figs., 7 refs.

  20. Laser resonant ionization spectroscopy and laser-induced resonant fluorescence spectra of samarium atom

    International Nuclear Information System (INIS)

    Jin, Changtai

    1995-01-01

    We have measured new high-lying levels of Sm atom by two-colour resonant photoionisation spectroscopy; we have observed the isotope shifts of Sm atom by laser-induced resonant fluorescence spectroscopy; the lifetime of eight low-lying levels of Sm atom were measured by using pulsed laser-Boxcar technique in atomic beam.

  1. Laser-Induced Fluorescence (LIF) from plant foliage

    Science.gov (United States)

    Chappelle, Emmett W.; Williams, Darrel L.

    1987-01-01

    The fluorescence spectra and fluorescence induction kinetics of green plants excited at 337 nm by a laser were studied. They correlate with plant type, as well as with changes in the physiology of the plant as the result of stress. The plant types studied include herbaceous dicots, monocots, hardwoods, conifers, and algae. These plant types could be identified on the basis of differences in either the number of fluorescent bands or the relative intensity of the bands. Differences in fluorescent spectra which could be related to vigor status are observed in conifers located in an area of high atmospheric deposition. Changes in the fluorescence spectra and induction kinetics are also seen in plants grown under conditions of nutrient deficiency and drought stress.

  2. Spatial variability of oceanic phycoerythrin spectral types derived from airborne laser-induced fluorescence emissions

    Science.gov (United States)

    Hoge, Frank E.; Wright, C. Wayne; Kana, Todd M.; Swift, Robert N.; Yungel, James K.

    1998-07-01

    We report spatial variability of oceanic phycoerythrin spectral types detected by means of a blue spectral shift in airborne laser-induced fluorescence emission. The blue shift of the phycoerythrobilin fluorescence is known from laboratory studies to be induced by phycourobilin chromophore substitution at phycoerythrobilin chromophore sites in some strains of phycoerythrin-containing marine cyanobacteria. The airborne 532-nm laser-induced phycoerythrin fluorescence of the upper oceanic volume showed distinct segregation of cyanobacterial chromophore types in a flight transect from coastal water to the Sargasso Sea in the western North Atlantic. High phycourobilin levels were restricted to the oceanic (oligotrophic) end of the flight transect, in agreement with historical ship findings. These remotely observed phycoerythrin spectral fluorescence shifts have the potential to permit rapid, wide-area studies of the spatial variability of spectrally distinct cyanobacteria, especially across interfacial regions of coastal and oceanic water masses. Airborne laser-induced phytoplankton spectral fluorescence observations also further the development of satellite algorithms for passive detection of phytoplankton pigments. Optical modifications to the NASA Airborne Oceanographic Lidar are briefly described that permitted observation of the fluorescence spectral shifts.

  3. Determination of nuclear spins of short-lived isotopes by laser induced fluorescence

    International Nuclear Information System (INIS)

    Buchinger, F.; Dabkiewicz, P.; Kremmling, H.; Kuehl, T.; Mueller, A.C.; Schuessler, H.A.

    1980-01-01

    The spins of several nuclear ground and isomeric states have been measured for a number of mercury isotopes. The fluorescent light from the 6s6p 3 P 1 state is observed at 2537 Angstroem after excitation with the frequency doubled output of a pulsed dye laser. Four different laser induced fluorescence techniques were tested for their applicability: double resonance, Hanle effect, time delayed integral Hanle beats, and time resolved quantum beats. The sensitivity and selectivity of these models are compared with emphasis on the determination of spins of nuclei far from beta-stability, where short half lives and low production yields restrict the number of available atoms. The experiments were carried out on-line with the ISOLDE isotope separator at CERN at densities as low as 10 6 atoms/cm 3 . Results for the very neutron deficient high spin mercury isomers with half lives of several seconds, but also for the ground states of the abundant low spin stable mercury isotopes, are given as examples. The test measurements determined the nuclear spins of the odd sup(185m-191m)Hg isomers to be I = 13/2. (orig.)

  4. Experimental Research of Reliability of Plant Stress State Detection by Laser-Induced Fluorescence Method

    Directory of Open Access Journals (Sweden)

    Yury Fedotov

    2016-01-01

    Full Text Available Experimental laboratory investigations of the laser-induced fluorescence spectra of watercress and lawn grass were conducted. The fluorescence spectra were excited by YAG:Nd laser emitting at 532 nm. It was established that the influence of stress caused by mechanical damage, overwatering, and soil pollution is manifested in changes of the spectra shapes. The mean values and confidence intervals for the ratio of two fluorescence maxima near 685 and 740 nm were estimated. It is presented that the fluorescence ratio could be considered a reliable characteristic of plant stress state.

  5. Teaching laser-induced fluorescence of plant leaves

    Science.gov (United States)

    Lenk, Sándor; Gádoros, Patrik; Kocsányi, László; Barócsi, Attila

    2016-11-01

    Plants convert carbon dioxide into sugars using the energy of sunlight. Absorbed light unused for conversion is dissipated primarily as heat with a small fraction re-emitted as fluorescence at longer wavelengths. One can use the latter to estimate photosynthetic activity. The illumination of intact leaves with strong light after keeping them in dark for tens of minutes results in a rapid increase followed by a slow decay of fluorescence emission from the fluorophore chlorophyll-a, called the Kautsky effect. This paper describes a laboratory practice that introduces students of physics or engineering into this research field. It begins with the spectral measurement of the fluorescence emitted by a plant leaf upon UV excitation. Then it focuses on the red and far-red components of the fluorescence emission spectrum characteristic to the chlorophyll-a molecule and presents an inexpensive demonstration of the Kautsky effect. As researchers use more complex measurement techniques and tools, the practice ends up with the demonstration of an intelligent fluorosensor, a compact tool developed for plant physiological research and horticulture applications together with a brief interpretation of some important fluorescence parameters.

  6. Teaching laser-induced fluorescence of plant leaves

    International Nuclear Information System (INIS)

    Lenk, Sándor; Gádoros, Patrik; Kocsányi, László; Barócsi, Attila

    2016-01-01

    Plants convert carbon dioxide into sugars using the energy of sunlight. Absorbed light unused for conversion is dissipated primarily as heat with a small fraction re-emitted as fluorescence at longer wavelengths. One can use the latter to estimate photosynthetic activity. The illumination of intact leaves with strong light after keeping them in dark for tens of minutes results in a rapid increase followed by a slow decay of fluorescence emission from the fluorophore chlorophyll -a , called the Kautsky effect. This paper describes a laboratory practice that introduces students of physics or engineering into this research field. It begins with the spectral measurement of the fluorescence emitted by a plant leaf upon UV excitation. Then it focuses on the red and far-red components of the fluorescence emission spectrum characteristic to the chlorophyll -a molecule and presents an inexpensive demonstration of the Kautsky effect. As researchers use more complex measurement techniques and tools, the practice ends up with the demonstration of an intelligent fluorosensor, a compact tool developed for plant physiological research and horticulture applications together with a brief interpretation of some important fluorescence parameters. (paper)

  7. Rotationally cooled laser induced fluorescence determination of polycyclic aromatic hydrocarbons

    International Nuclear Information System (INIS)

    Warren, J.A.; Hayes, J.M.; Small, G.J.

    1982-01-01

    In recent years the development of new highly selective and sensitive methods for the characterization and determination of polycyclic aromatic hydrocarbons (PAHs) and their derivatives in complex mixtures has received considerable attention. High selectivity is associated here with the ability to distinguish between substitutional isomers of PAHs. Attainment of this selectivity with capillary column-gas chromatography-mass spectrometry for complex mixtures is very difficult and time-consuming. Alternative approaches are, therefore, required. Given that the majority of PAHs fluoresce with reasonable quantum yields and that high sensitivities are afforded by fluorescence detection, the possibility of developing high-resolution fluorescence based techniques is attractive. This is all the more so if the technique's selectivity does not rely on physical separation, e.g., chromatography. In this paper discussion is limited to such techniques

  8. Laser-induced Fluorescence Spectroscopy for applications in chemical sensing and optical refrigeration

    Science.gov (United States)

    Kumi Barimah, Eric

    limit of detection for ClO4, was determined to be 14.7 +/- 0.5 wt%/wt for the given experimental conditions. In the second part of this research, the temperature-dependent absorption and emission properties of Tm doped KPb2Cl5 (KPC) and KPb2Br5 (KPB) were evaluated for applications in laser cooling. A Tm doped Y3Al5O12 (YAG) crystal was also included for comparative studies. Under laser pumping, all crystals exhibited broad IR fluorescence at room temperature with a mean fluorescence wavelength of ˜1.82 mum and bandwidth of 0.14 mum (FWHM) for Tm:KPC/KPB and ˜1.79 mum for Tm:YAG. Initial experiments on laser-induced heating/cooling were performed using a combined IR imaging and fluorescence thermometry setup. Employing a continuous-wave laser operating at 1.907 mum, Tm: KPC and Tm: KPB crystals revealed a very small heat load resulting in temperature increase of ˜ 0.3 ( +/- 0.1)°C. The heat loading in Tm:YAG was signicantly larger and resulted in a temperature increase of ˜0.9 (+/-0.1)°C. The results derived from IR imaging were also conrmed by the fluorescence thermometry experiments, which showed only minimal changes in the FIR intensity ratio of the green Er3+ fluorescence lines from Er:KPC.

  9. Laser induced fluorescence technique for detecting organic matter in East China Sea

    Science.gov (United States)

    Chen, Peng; Wang, Tianyu; Pan, Delu; Huang, Haiqing

    2017-10-01

    A laser induced fluorescence (LIF) technique for fast diagnosing chromophoric dissolved organic matter (CDOM) in water is discussed. We have developed a new field-portable laser fluorometer for rapid fluorescence measurements. In addtion, the fluorescence spectral characteristics of fluorescent constituents (e.g., CDOM, chlorophyll-a) were analyzed with a spectral deconvolution method of bi-Gaussian peak function. In situ measurements by the LIF technique compared well with values measured by conventional spectrophotometer method in laboratory. A significant correlation (R2 = 0.93) was observed between fluorescence by the technique and absorption by laboratory spectrophotometer. Influence of temperature variation on LIF measurement was investigated in lab and a temperature coefficient was deduced for fluorescence correction. Distributions of CDOM fluorescence measured using this technique in the East China Sea coast were presented. The in situ result demonstrated the utility of the LIF technique for rapid detecting dissolved organic matter.

  10. Quantitative analysis of essential oils of Thymus daenensis using laser-induced fluorescence and Raman spectroscopy.

    Science.gov (United States)

    Khoshroo, H; Khadem, H; Bahreini, M; Tavassoli, S H; Hadian, J

    2015-11-10

    Laser-induced fluorescence and Raman spectroscopy are used for the investigation of different genotypes of Thymus daenensis native to the Ilam province of Iran. Different genotypes of T. daenensis essential oils, labeled T1 through T7, possess slight differences with regard to the composition of the thymol. The gas chromatography-mass spectrometry (GC-MS) method is performed to determine the concentration of each constituent as a reference method. The Raman spectra of different concentrations of pure thymol dissolved in hexane as standard samples are obtained via a laboratory prototype Raman spectroscopy setup for the calculation of the calibration curve. The regression coefficient and limit of detection are calculated. The possibility of the differentiation of different genotypes of T. daenensis is also examined by laser-induced fluorescence spectroscopy, although we do not know the exact amounts of their components. All the fluorescence spectral information is used jointly by cluster analysis to differentiate between 7 genotypes. Our results demonstrate the acceptable precision of Raman spectroscopy with GC-MS and corroborate the capacity of Raman spectroscopy in applications in the quantitative analysis field. Furthermore, the cluster analysis results show that laser-induced fluorescence spectroscopy is an acceptable technique for the rapid classification of different genotypes of T. daenensis without having any previous information of their exact amount of constituents. So, the ability to rapidly and nondestructively differentiate between genotypes makes it possible to efficiently select high-quality herbs from many samples.

  11. Visualization of Two-Phase Fluid Distribution Using Laser Induced Exciplex Fluorescence

    Science.gov (United States)

    Kim, J. U.; Darrow, J.; Schock, H.; Golding, B.; Nocera, D.; Keller, P.

    1998-03-01

    Laser-induced exciplex (excited state complex) fluorescence has been used to generate two-dimensional images of dispersed liquid and vapor phases with spectrally resolved two-color emissions. In this method, the vapor phase is tagged by the monomer fluorescence while the liquid phase is tracked by the exciplex fluorescence. A new exciplex visualization system consisting of DMA and 1,4,6-TMN in an isooctane solvent was developed.(J.U. Kim et al., Chem. Phys. Lett. 267, 323-328 (1997)) The direct ca

  12. Direct visualization of secretion from single bovine adrenal chromaffin cells by laser-induced native fluorescence imaging microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tong, W.; Yeung, E.S. [Ames Laboratory---USDOE and Department of Chemistry, Iowa State University, Ames, Iowa 50011 (United States)

    1998-03-01

    Direct visualization of the secretion process of individual bovine adrenal chromaffin cells was achieved with laser-induced native fluorescence imaging microscopy. By monitoring the native fluorescence of catecholamines excited by the 275 nm laser line with an intensified charge-coupled-device (CCD) camera, we obtained good temporal and spatial resolution simultaneously without using additional fluorescent probes. Large variations were found among individual cells in terms of the amounts of catecholamines secreted and the rates of secretion. Different regions of a cell also behave differently during the secretion process. However, the degree of this local heterogeneity is smaller than in neurons and neuralgia. The influence of deep-ultraviolet (UV) laser excitation on cells is also discussed. This quantitative imaging technique provides a useful noninvasive approach for the study of dynamic cellular changes and the understanding of the molecular mechanisms of secretory processes. {copyright} {ital 1998} {ital Society for Applied Spectroscopy}

  13. Examinations for the determination of the flux density of sputtered iron using laser induced fluorescence

    International Nuclear Information System (INIS)

    Schweer, H.B.

    1983-11-01

    In this work investigations are described to measure the flux density of sputtered iron atoms by means of laser induced fluorescence. In a laboratory experiment an iron target (stainless steel 316, Inconel 600), was bombarded with 10 keV Ar + and 2.5 keV H + and the population distribution of the energy levels of the ground state a 5 D and the metastable state a 5 F was measured. In the plasma wall region in the ISX-B tokamak at the Oak Ridge National Laboratory (USA) neutral iron atoms were measured the first time by laser induced fluorescence. A detection limit of 10 6 atoms/cm 3 was found and sputtered iron atoms were observed in the first 15 ms of the discharge. (orig./BRB)

  14. Time-resolved laser-induced fluorescence in the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Moulin, C.; Decambox, P.; Mauchien, P.; Petit, A.

    1995-01-01

    Time-Resolved Laser-Induced Fluorescence (TRLIF) is a very sensitive and selective method that has been used for actinides and lanthanides analysis in the nuclear fuel cycle. This technique has been used in different fields such as in geology, in the Purex process, in the environment, in the medical and in waste storage assessment. Spectroscopic data, limits of detection and results obtained in previously quoted fields are presented. (author)

  15. Two-photon laser-induced fluorescence studies of HS radicals, DS radicals, and I atoms

    Energy Technology Data Exchange (ETDEWEB)

    Tiee, J J; Ferris, M J; Loge, G W; Wampler, F B

    1983-04-15

    A two-photon laser-induced excitation and fluorescence technique has been used to study the A /sup 2/..sigma../sup +/ - X/sup 2/PI transition of HS and DS radicals and various high-lying /sup 4/P/sup 0/, /sup 2/D/sup 0/, and /sup 4/D/sup 0/ states of the I atom. The two-photon excitation cross sections and detection sensitivity are discussed. 13 references, 5 figures.

  16. Laser induced fluorescence spectroscopy in atomic beams of radioactive nuclides

    International Nuclear Information System (INIS)

    Rebel, H.; Schatz, G.

    1982-01-01

    Measurements of the resonant scattering of light from CW tunable dye lasers, by a well collimated atomic beam, enable hyperfine splittings and optical isotope shifts to be determined with high precision and high sensitivity. Recent off-line atomic beam experiments with minute samples, comprising measurements with stable and unstable Ba, Ca and Pb isotopes are reviewed. The experimental methods and the analysis of the data are discussed. Information on the variation of the rms charge radii and on electromagnetic moments of nuclei in long isotopic chains is presented. (orig.) [de

  17. Development of laser-induced fluorescence detection to assay DNA damage

    International Nuclear Information System (INIS)

    Sharma, M.; Freund, H.G.

    1991-01-01

    A precolumn derivation method has been developed for high performance liquid chromatographic (HPLC) analysis of DNA damage using fluorescence detection. The modified nucleotide, having excised enzymatically from the exposed DNA, is enriched from the normal nucleotides and labeled with a fluorescent reagent. The labeling procedure involves phosphoramidation of the nucleotide with ethylenediamine (EDA) followed by conjugation of the free amino end of the phosphoramidate with 5-dimethylaminonaphthalene 1-sulfonyl chloride, commonly known as Dansyl chloride. The dansylated nucleotide can be analyzed with a sub-picomole limit of detection (LOD) by conventional HPLC using a conventional fluorescence detector. By combining microbore HPLC with laser-induced fluorescence (LIF) detection, the authors present the development of an analytical system that has sub-femtomole LOD for real-time analysis of the dansylated nucleotide. In this paper the application of the developed system in fluorescence postlabeling assay of a small alkyl-modified nucleotide (5-methyl CMP) in calf-thymus DNA is discussed

  18. Novel xenon calibration scheme for two-photon absorption laser induced fluorescence of hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Drew; Scime, Earl; Short, Zachary, E-mail: zdshort@mix.wvu.edu [Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26056 (United States)

    2016-11-15

    Two photon absorption laser induced fluorescence (TALIF) measurements of neutral hydrogen and its isotopes are typically calibrated by performing TALIF measurements on krypton with the same diagnostic system and using the known ratio of the absorption cross sections [K. Niemi et al., J. Phys. D 34, 2330 (2001)]. Here we present the measurements of a new calibration method based on a ground state xenon scheme for which the fluorescent emission wavelength is nearly identical to that of hydrogen, thereby eliminating chromatic effects in the collection optics and simplifying detector calibration. We determine that the ratio of the TALIF cross sections of xenon and hydrogen is 0.024 ± 0.001.

  19. Non-destructive monitoring of agricultural product (lettuce [Lactuca sativa]) based on laser-induced fluorescence

    International Nuclear Information System (INIS)

    Ishizawa, H.; Saito, Y.; Amemiya, T.; Komatu, K.

    2002-01-01

    Quality control of agricultural products in process of cultivation and distribution has become an important problem. This paper describes a field measuring method of lettuce based on laser induced fluorescence (LIF) spectroscopy for growth monitoring. Intensity at 460nm of LIF spectra showed characteristic variations of near harvest time. The results of chemical analysis confirmed that sucrose and chlorogenic acid are origins of the 460nm fluorescence. The prediction of harvest time and the possibility of quality monitoring are discussed based on the experimental data

  20. Laser-induced fluorescence for the detection of esophageal and skin cancer

    Science.gov (United States)

    Vo-Dinh, Tuan; Panjehpour, Masoud; Overholt, Bergein F.; Julius, Clark E.; Overholt, Suzanne; Phan, Mary N.

    2003-07-01

    Laser-induced fluorescence (LIF) is used for in-vivo cancer diagnosis of the esophagus and skin cancer. For esophageal measurements a fiberoptic probe inserted through an endoscope was used. Autofluorescence of normal and malignant tissues were measured directly on patient skin without requiring an endoscope. Measurement of the fluorescence signal from the tissue was performed using laser excitation at 410 nm. The methodology was applied to differentiate normal and malignant tumors of the esophagus and malignant skin lesions. The results of this LIF approach were compared with histopathology results of the biopsy samples and indicated excellent agreement in the classification of normal and malignant tumors for the samples investigated.

  1. Measurements of KrF laser-induced O2 fluorescence in high-temperature atmospheric air

    Science.gov (United States)

    Grinstead, Jay H.; Laufer, Gabriel; Mcdaniel, James C., Jr.

    1993-01-01

    Conditions for obtaining laser-induced O2 fluorescence using a tunable KrF laser has been determined theoretically and experimentally. With this laser source, O2 rotational temperature measurement is possible even in the absence of vibrational equilibrium. Temperature measurement using a two-line excitation scheme has been demonstrated in a high-temperature atmospheric-air furnace. A measurement uncertainty of 10.7 percent for the temperature range 1325-1725 K was realized. At atmospheric pressure, O2 LIF measurements are possible for air temperatures above 1250 K. Interference from OH fluorescence in reacting flows can be avoided by the proper selection of O2 transitions. Depletion of the ground state population by the incident laser is negligible for intensities below 7.5 x 10 to the 6th W/sq cm/per cm.

  2. Remote imaging laser-induced breakdown spectroscopy and laser-induced fluorescence spectroscopy using nanosecond pulses from a mobile lidar system.

    Science.gov (United States)

    Grönlund, Rasmus; Lundqvist, Mats; Svanberg, Sune

    2006-08-01

    A mobile lidar system was used in remote imaging laser-induced breakdown spectroscopy (LIBS) and laser-induced fluorescence (LIF) experiments. Also, computer-controlled remote ablation of a chosen area was demonstrated, relevant to cleaning of cultural heritage items. Nanosecond frequency-tripled Nd:YAG laser pulses at 355 nm were employed in experiments with a stand-off distance of 60 meters using pulse energies of up to 170 mJ. By coaxial transmission and common folding of the transmission and reception optical paths using a large computer-controlled mirror, full elemental imaging capability was achieved on composite targets. Different spectral identification algorithms were compared in producing thematic data based on plasma or fluorescence light.

  3. Laser-induced fluorescence imaging of acetone inside evaporating and burning fuel droplets

    Science.gov (United States)

    Shringi, D. S.; Shaw, B. D.; Dwyer, H. A.

    2009-01-01

    Laser-induced fluorescence was used to visualize acetone fields inside individual droplets of pure acetone as well as droplets composed of methanol or 1-propanol initially mixed with acetone. Droplets were supported on a horizontal wire and two vaporization conditions were investigated: (1) slow evaporation in room air and (2) droplet combustion, which leads to substantially faster droplet surface regression rates. Acetone was preferentially gasified, causing its concentration in droplets to drop in time with resultant decreases in acetone fluorescence intensities. Slowly vaporizing droplets did not exhibit large spatial variations of fluorescence within droplets, indicating that these droplets were relatively well mixed. Ignition of droplets led to significant variations in fluorescence intensities within droplets, indicating that these droplets were not well mixed. Ignited droplets composed of mixtures of 1-propanol and acetone showed large time-varying changes in shapes for higher acetone concentrations, suggesting that bubble formation was occurring in these droplets.

  4. Laser-induced fluorescences due to quadrupole moment transition and Stark effect in a He glow discharge

    International Nuclear Information System (INIS)

    Sakai, Hisashi; Takiyama, Ken; Kimura, Masahiko; Yamasaki, Motokuni; Fujita, Toshiaki; Oda, Toshiatsu; Kawasaki, Ken.

    1993-01-01

    The electric quadrupole moment transition and the Stark effect are investigated in a He hollow cathode discharge with laser-induced fluorescence method. It is shown that the forbidden transition from 2 1 S to 3 1 D in the negative glow is dominantly due to the quadrupole moment transition. This absorption coefficient is obtained from the laser-induced fluorescence intensity measurement in which the collisional transfers are taken into account. The result agrees with the theoretical coefficient. In the cathode dark space the fluorescence due to the Stark effect is also observed. Spatial distribution of the fluorescence is discussed, compared with the electric field distribution in the dark space. (author)

  5. Laser induced fluorescence thermometry (LIF-T) as a non-invasive temperature measurement technique for thermal hydraulic experiments

    Energy Technology Data Exchange (ETDEWEB)

    Strack, J.; Leung, K.; Walker, A., E-mail: strackj@mcmaster.ca [McMaster Univ., Hamilton, ON (Canada)

    2014-07-01

    Laser induced fluorescence (LIF) is an experimental technique whereby a scalar field in a fluid system is measured optically from the fluorescence intensity of a tracer dye following excitation by laser light. For laser induced fluorescence thermometry (LIF-T), a temperature sensitive dye is used. Through the use of a temperature sensitive tracer dye, sheet laser optics, optical filters, and photography, a 2D temperature field can be measured non-invasively. An experiment to test the viability of using LIF-T for macroscopic thermal hydraulic experiments was developed and tested. A reference calibration curve to relate fluorescence measurements to temperature is presented. (author)

  6. Blood perfusion and pH monitoring in organs by laser-induced fluorescence spectroscopy

    Science.gov (United States)

    Vari, Sandor G.; Papazoglou, Theodore G.; Pergadia, Vani R.; Stavridi, Marigo; Snyder, Wendy J.; Papaioannou, Thanassis; Duffy, J. T.; Weiss, Andrew B.; Thomas, Reem; Grundfest, Warren S.

    1994-01-01

    Sensitivity of laser-induced fluorescence spectroscopy (LIFS) in detecting a change in tissue pH, and blood perfusion was determined. Rabbits were anesthetized, paralyzed, and mechanically ventilated. The arterial and venous blood supplies of the kidney were isolated and ligated to alter the perfusion. The femoral artery was cannulated to extract samples for blood gas analysis. A 308-nm XeCl was used as an excitation source. A 600 micrometers core diameter fiber was used for fluorescence acquisition, and the spectra analyzed by an optical multichannel analyzer (EG & G, OMA III). the corresponding intensity ratio R equals INADH / ICOLL was used as an index for respiratory acidosis. Blood perfusion was assessed using the following algorithm: (IELAS minus ICOLL) divided by (INADH minus ICOLL). The intensity ratio linearly decreased with the reduction of blood perfusion. When we totally occluded the artery the ratio decreased tenfold when compared to the ratio of a fully perfused kidney. Results of monitoring blood acidosis by laser-induced fluorescence spectroscopy shows a significant trend between pH and intensity ratio. Since all the slopes were negative, there is an obvious significant correlation between the pH and NADH.COLLAGEN RATIO. Blue-light-induced fluorescence measurements and ratio fluorometry is a sensitive method for monitoring blood perfusion and acidity or alkalinity of an organ.

  7. Instantaneous imaging of ozone in a gliding arc discharge using photofragmentation laser-induced fluorescence

    Science.gov (United States)

    Larsson, Kajsa; Hot, Dina; Gao, Jinlong; Kong, Chengdong; Li, Zhongshan; Aldén, Marcus; Bood, Joakim; Ehn, Andreas

    2018-04-01

    Ozone vapor, O3, is here visualized in a gliding arc discharge using photofragmentation laser-induced fluorescence. Ozone is imaged by first photodissociating the O3 molecule into an O radical and a vibrationally hot O2 fragment by a pump photon. Thereafter, the vibrationally excited O2 molecule absorbs a second (probe) photon that further transits the O2-molecule to an excited electronic state, and hence, fluorescence from the deexcitation process in the molecule can be detected. Both the photodissociation and excitation processes are achieved within one 248 nm KrF excimer laser pulse that is formed into a laser sheet and the fluorescence is imaged using an intensified CCD camera. The laser-induced signal in the vicinity of the plasma column formed by the gliding arc is confirmed to stem from O3 rather than plasma produced vibrationally hot O2. While both these products can be produced in plasmas a second laser pulse at 266 nm was utilized to separate the pump- from the probe-processes. Such arrangement allowed lifetime studies of vibrationally hot O2, which under these conditions were several orders of magnitude shorter than the lifetime of plasma-produced ozone.

  8. Capillary electrophoresis hyphenated with UV-native-laser induced fluorescence detection (CE/UV-native-LIF).

    Science.gov (United States)

    Couderc, François; Ong-Meang, Varravaddheay; Poinsot, Véréna

    2017-01-01

    Native laser-induced fluorescence using UV lasers associated to CE offers now a large related literature, for now 30 years. The main works have been performed using very expensive Ar-ion lasers emitting at 257 and 275 nm. They are not affordable for routine analyses, but have numerous applications such as protein, catecholamine, and indolamine analysis. Some other lasers such as HeCd 325 nm have been used but only for few applications. Diode lasers, emitting at 266 nm, cheaper, are extensively used for the same topics, even if the obtained sensitivity is lower than the one observed using the costly UV-Ar-ion lasers. This review presents various CE or microchips applications and different UV lasers used for the excitation of native fluorescence. We showed that CE/Native UV laser induced fluorescence detection is very sensitive for detection as well as small aromatic biomolecules than proteins containing Trp and Tyr amino acids. Moreover, it is a simple way to analyze biomolecules without derivatization. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Two-color planar laser-induced fluorescence thermometry in aqueous solutions

    International Nuclear Information System (INIS)

    Robinson, G. Andrew; Lucht, Robert P.; Laurendeau, Normand M.

    2008-01-01

    We demonstrate a two-color planar laser-induced fluorescence technique for obtaining two-dimensional temperature images in water. For this method, a pulsed Nd:YAG laser at 532 nm excites a solution of temperature-sensitive rhodamine 560 and temperature-insensitive sulforhodamine 640. The resulting emissions are optically separated through filters and detected via a charged-couple device (CCD) camera system. A ratio of the two images yields temperature images independent of incident irradiance. An uncertainty in temperature of ±1.4 deg. C is established at the 95% confidence interval

  10. Flame Front Detection Using Formaldehyde Laser Induced Fluorescence In Turbulent Lean Premixed Flames

    Energy Technology Data Exchange (ETDEWEB)

    Schenker, S.; Tylli, N.; Bombach, R.

    2005-03-01

    The present work aims at suggesting the excitation-detection scheme best suited for laser-induced fluorescence measurements of formaldehyde in turbulent lean premixed flames. In the literature, three different excitation schemes within the A{sup 1} X{sup 1} electronic transition have been suggested, with excitation into the 2{sup 1}{sub 0} 4{sup 1}{sub 0} , 4{sup 1}{sub 0} , and 4{sup 0}{sub 1} vibratoric bands, respectively. These excitation schemes were tested systematically and both advantages and disadvantages for each scheme are discussed. (author)

  11. Direct measurements of neutral density depletion by two-photon absorption laser-induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Aanesland, A.; Liard, L.; Leray, G.; Jolly, J.; Chabert, P.

    2007-01-01

    The ground state density of xenon atoms has been measured by spatially resolved laser-induced fluorescence spectroscopy with two-photon excitation in the diffusion chamber of a magnetized Helicon plasma. This technique allows the authors to directly measure the relative variations of the xenon atom density without any assumptions. A significant neutral gas density depletion was measured in the core of the magnetized plasma, in agreement with previous theoretical and experimental works. It was also found that the neutral gas density was depleted near the radial walls

  12. Measurement of isotope shift of recycled uranium by laser induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Oba, Masaki; Wakaida, Ikuo; Akaoka, Katsuaki; Miyabe, Masabumi

    1999-07-01

    Isotope shift of the recycled uranium atoms including the 236 U was measured by laser induced fluorescence method. Eight even levels at 2 eV and three odd levels at 4 eV were measured with isotope shifts among 238 U, 236 U and 235 U obtained. As for the measurement of the 4 eV levels, the Doppler free two photon absorption method was used, and the hyperfine structure of the 235 U was analyzed simultaneously. The isotope shift of 234 U was also observed in the three transition. (J.P.N.)

  13. Measurement of changes in nuclear charge radii of 2r by laser-induced resonance fluorescence

    International Nuclear Information System (INIS)

    Gangrskij, Yu.P.; Zemlyanoj, S.G.; Marinova, K.P.; Markov, B.N.; Khoang Tkhi Kim Khueh; Chan Kong Tam; Kul'dzhanov, B.K.

    1987-01-01

    The optical isotopic shifts of Zr stable isotopes have been measured in three atomic transitions of type 4d 2 5s 2 → 4d 2 5s5p using the technique of laser-induced resonance fluorescence. The changes of nuclear mean-square charge radius Δ 2 > have been determined. The extracted values of Δ 2 > are compared to predictions of the droplet model. It is shown that the droplet model calculations can be made to agree with the experimental results, if changes of nuclear dynamical octupole deformation and of surface diffuseness parameter are taken into account

  14. Detection of potassium deficiency on palm oil tree (Elaeis guineensis (jacq)) by laser induced fluorescence

    International Nuclear Information System (INIS)

    Diomande, K.; Konate, A.; Krou Adjo, V.; Soro, A.; Ebby, N.; Ballo, K.

    1998-02-01

    The potassium is the main nutrient element which plays a significant role on oil palm tree (Elaeis guineensis (jacq)) production and its resistance to the dry season. One can observe 30% decrease of the production in case of potassium deficiency. The potassium nutrition control of an oil palm tree field is a very important activity and leads to the fertilization policy. The Laser Induced Fluorescence (L.I.F.) is a fast and simple method compared to the classical one, ''Diagnostic Foliaire'', usually used in agronomy. We used the L.I.F. method to detect the oil palm tree stress caused by potassium deficiency, analysing the fluorescence spectrum of the chlorophyll a. We proved that the intensity ratio of the fluorescence spectrum R=F690/F73S is superior to 0.5 when the tree is under stress and its value is around 0.4 in case of intact tree. (author)

  15. In-vivo cancer diagnosis of the esophagus using laser-induced fluorescence

    Science.gov (United States)

    Vo-Dinh, Tuan; Panjehpour, Masoud; Overholt, Bergein F.; Buckley, Paul F., II; Edwards, Donna H.

    1995-04-01

    Laser-induced fluorescence (LIF) was used for direct in-vivo cancer diagnosis of the esophagus without requiring biopsy. The methodology was applied to differentiate normal and malignant tumors of the esophagus. Endogenous fluorescence of normal and malignant tissues were measured directly using a fiberoptic probe inserted through an endoscope. The measurements were performed in vivo during routine endoscopy. Detection of the fluorescence signal from the tissue was performed using laser excitation. The results of this LIF approach were compared with histopathology results of the biopsy samples and indicated excellent agreement in the classification of normal and malignant tumors for the samples investigated. The LIF procedure could lead to the development of a rapid and cost-effective technique for cancer diagnosis.

  16. Quantitative nitric oxide measurements by means of laser-induced fluorescence in a heavy-duty Diesel engine

    NARCIS (Netherlands)

    Verbiezen, K.; Vliet, van A.P.; Klein-Douwel, R.J.H.; Ganippa, L.C.; Bougie, H.J.T.; Meerts, W.L.; Dam, N.J.; Meulen, ter J.J.

    2005-01-01

    Quantitative in-cylinder laser-induced fluorescence measurements ofnitric oxide in a heavy-duty Diesel engine are presented. Special attention is paid to experimental techniques to assess the attenuation of the laser beam and the fluorescence signal by the cylinder contents.This attenuation can be

  17. Experimental Studies of Laser-Induced Fluorescence Spectra of Plants Immunity to the Kind of Ground

    Directory of Open Access Journals (Sweden)

    Yu. V. Fedotov

    2015-01-01

    Full Text Available Various external factors (pollutants available in the soil, a lack or insufficient amount of water and nutrients, etc. lead to stressful conditions of plants and impossibility of their normal development. At the early stages it is difficult to identify visually the stressful situations of plants. Therefore development of methods and devices to detect stressful states is important.A method of the laser-induced fluorescence is one of perspective methods for detection of stressful conditions of plants.In spite of quite a great number of work presenting results of the pilot studies of fluorescence spectra of vegetation, there are some important issues, which are unclear.The paper gives results of pilot studies of stability of a spectrum form of the laser-induced fluorescence of plants for different types of soil at the wavelength of excitation fluorescence of 532 nm.Results of processing fluorescence spectra of plants show:- fluorescence spectra of plants grown up under similar conditions have good repeatability of a spectra form for different samples of plants and different measurement time for each type of studied soil. The ratio value R of the fluorescence intensity at the wavelength of 685 nm to the fluorescence intensity at the wavelength of 740 nm has high stability. The standard deviation in sampling of the ratio R of different samples of a plant for one type of soil (for width of spectral ranges of recording fluorescent radiation of 10 nm lies in the range ~ 0.055 - ~ 0.12;- a difference in plant fluorescence spectra between themselves for different types of soil has the same order as a difference in fluorescence spectra of different samples of a plant for one type of soil. Difference in average value of the ratio R for different types of soil lies in the range ~ 0.01 - ~ 0.15.Thus, the value of the ratio R is steady against a type of soil and can be used to control a condition of plants.

  18. Two Photon Absorption Laser Induced Fluorescence for Neutral Hydrogen Profile Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Scime, Earl E. [West Virginia Univ., Morgantown, WV (United States)

    2016-09-23

    The magnitude and spatial dependence of neutral density in magnetic confinement fusion experiments is a key physical parameter, particularly in the plasma edge. Modeling codes require precise measurements of the neutral density to calculate charge-exchange power losses and drag forces on rotating plasmas. However, direct measurements of the neutral density are problematic. In this work, we proposed to construct a laser-based diagnostic capable of providing spatially resolved measurements of the neutral density in the edge of plasma in the DIII-D tokamak. The diagnostic concept is based on two-photon absorption laser induced fluorescence (TALIF). By injecting two beams of 205 nm light (co or counter propagating), ground state hydrogen (or deuterium or tritium) can be excited from the n = 1 level to the n = 3 level at the location where the two beams intersect. Individually, the beams experience no absorption, and therefore have no difficulty penetrating even dense plasmas. After excitation, a fraction of the hydrogen atoms decay from the n = 3 level to the n = 2 level and emit photons at 656 nm (the Hα line). Calculations based on the results of previous TALIF experiments in magnetic fusion devices indicated that a laser pulse energy of approximately 3 mJ delivered in 5 ns would provide sufficient signal-to-noise for detection of the fluorescence. In collaboration with the DIII-D engineering staff and experts in plasma edge diagnostics for DIII-D from Oak Ridge National Laboratory (ORNL), WVU researchers designed a TALIF system capable of providing spatially resolved measurements of neutral deuterium densities in the DIII-D edge plasma. The laser systems were specified, purchased, and assembled at WVU. The TALIF system was tested on a low-power hydrogen discharge at WVU and the plan was to move the instrument to DIII-D for installation in collaboration with ORNL researchers. After budget cuts at DIII-D, the DIII-D facility declined to support

  19. Two Photon Absorption Laser Induced Fluorescence for Neutral Hydrogen Profile Measurements

    International Nuclear Information System (INIS)

    Scime, Earl E.

    2016-01-01

    The magnitude and spatial dependence of neutral density in magnetic confinement fusion experiments is a key physical parameter, particularly in the plasma edge. Modeling codes require precise measurements of the neutral density to calculate charge-exchange power losses and drag forces on rotating plasmas. However, direct measurements of the neutral density are problematic. In this work, we proposed to construct a laser-based diagnostic capable of providing spatially resolved measurements of the neutral density in the edge of plasma in the DIII-D tokamak. The diagnostic concept is based on two-photon absorption laser induced fluorescence (TALIF). By injecting two beams of 205 nm light (co or counter propagating), ground state hydrogen (or deuterium or tritium) can be excited from the n = 1 level to the n = 3 level at the location where the two beams intersect. Individually, the beams experience no absorption, and therefore have no difficulty penetrating even dense plasmas. After excitation, a fraction of the hydrogen atoms decay from the n = 3 level to the n = 2 level and emit photons at 656 nm (the H α line). Calculations based on the results of previous TALIF experiments in magnetic fusion devices indicated that a laser pulse energy of approximately 3 mJ delivered in 5 ns would provide sufficient signal-to-noise for detection of the fluorescence. In collaboration with the DIII-D engineering staff and experts in plasma edge diagnostics for DIII-D from Oak Ridge National Laboratory (ORNL), WVU researchers designed a TALIF system capable of providing spatially resolved measurements of neutral deuterium densities in the DIII-D edge plasma. The laser systems were specified, purchased, and assembled at WVU. The TALIF system was tested on a low-power hydrogen discharge at WVU and the plan was to move the instrument to DIII-D for installation in collaboration with ORNL researchers. After budget cuts at DIII-D, the DIII-D facility declined to support installation on their

  20. UV laser-induced fluorescence spectroscopy and laser Doppler flowmetry in the diagnostics of alopecia

    Science.gov (United States)

    Skomorokha, Diana P.; Pigoreva, Yulia N.; Salmin, Vladimir V.

    2016-04-01

    Development of optical biopsy methods has a great interest for medical diagnostics. In clinical and experimental studies it is very important to analyze blood circulation quickly and accurately, thereby laser Doppler flowmetry (LDF) is widely used. UV laser-induced fluorescence spectroscopy (UV LIFS) is express highly sensitive and widely-spread method with no destructive impact, high excitation selectivity and the possibility to use in highly scattering media. The goal of this work was to assess a correlation of UV laser-induced fluorescence spectroscopy and laser Doppler flowmetry parameters, and a possibility to identify or to differentiate various types of pathological changes in tissues according to their autofluorescence spectra. Three groups of patients with diffuse (symptomatic) alopecia, androgenic alopecia, and focal alopecia have been tested. Each groups consisted of not less than 20 persons. The measurements have been done in the parietal and occipital regions of the sculls. We used the original automated spectrofluorimeter to record autofluorescence spectra, and standard laser Doppler flowmeter BLF-21 (Transonic Systems, Inc., USA) to analyze the basal levels of blood circulation. Our results show that UV LIFS accurately distinguishes the zones with different types of alopecia. We found high correlation of the basal levels of blood circulation and the integrated intensity of autofluorescence in the affected tissue.

  1. Laser-induced fluorescence studies of premalignant and benign lesions in the female genital tract

    Science.gov (United States)

    af Klinteberg, Claes; Wang, Ingrid; Lindquist, Charlotta; Vaitkuviene, Aurelija; Svanberg, Katarina

    1997-12-01

    Laser-induced fluorescence (LIF) was studied in vivo from premalignant and benign lesions in the female genital tract, in particular the cervix. The aim of the study was to investigate the possibilities to differentiate cervical intraepithelial neoplasia (CIN) from normal tissue by means of two different fluorescence modalities. Most of the patients were given a low dose (5 mg/kg bw) of (delta) -amino levulinic acid (ALA). The ALA was orally administered 2 - 4 hours prior to the investigation. During this time, the ALA is transformed to the strongly fluorescent protoporphyrin IX (PpIX) via the haem cycle. Excitation light with a wavelength of 405 nm was used to excite the PpIX fluorescence. Excess amounts of PpIX were accumulated preferentially in diseased tissue. However, the variability in the PpIX accumulation from patient to patient was large. By using excitation light at 337 nm, the endogenous fluorophores are more efficiently excited. Therefore, this excitation modality was exploited for studying spectral characteristics of the autofluorescence in different tissue types. The spectra obtained were evaluated by forming fluorescence intensity ratios. The tissue types were grouped according to the histopathological examination. A correlation with the fluorescence ratios was performed. Some problems with the classification remain, mostly due to the difficulties in obtaining histopathologic evaluation of the biopsies at the exact location of the LIF measurements.

  2. Diagnostics of Susabi-nori (Porphyra Yezoensis) by Laser-Induced Fluorescence Method

    Science.gov (United States)

    Okamoto, Tamotsu; Nakamura, Yuki; Takahashi, Kunio; Kaneko, Shohei; Shimada, Yuji

    Susabi-nori (Porphyra yezoensis) was diagnosed by means of laser-induced fluorescence (LIF) method. Fluorescence peaks located at approximately 580, 660, 685 and 720 nm were observed in the LIF spectra of Susabi-nori. In the spectrum of the sample infected with the red rot disease, the intensity of 580 nm peak was relatively high as compared with that of the control sample. On the other hand, the intensities of 580 nm and 660 nm peaks drastically decreased by the influence of the chytrid disease. Furthermore, the intensity of the 580 nm peak increased by dipping into fresh water. These results indicate that LIF spectra of Susabi-nori are affected by the diseases and the stress of fresh water and that the diseases and the stress of Susabi-nori can be diagnosed by the LIF method.

  3. Detection of biological warfare agents using ultra violet-laser induced fluorescence LIDAR.

    Science.gov (United States)

    Joshi, Deepti; Kumar, Deepak; Maini, Anil K; Sharma, Ramesh C

    2013-08-01

    This review has been written to highlight the threat of biological warfare agents, their types and detection. Bacterial biological agent Bacillus anthracis (bacteria causing the disease anthrax) which is most likely to be employed in biological warfare is being discussed in detail. Standoff detection of biological warfare agents in aerosol form using Ultra violet-Laser Induced Fluorescence (UV-LIF) spectroscopy method has been studied. Range-resolved detection and identification of biological aerosols by both nano-second and non-linear femto-second LIDAR is also discussed. Calculated received fluorescence signal for a cloud of typical biological agent Bacillus globigii (Simulants of B. anthracis) at a location of ~5.0 km at different concentrations in presence of solar background radiation has been described. Overview of current research efforts in internationally available working UV-LIF LIDAR systems are also mentioned briefly. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. A LabVIEW-Based Virtual Instrument System for Laser-Induced Fluorescence Spectroscopy.

    Science.gov (United States)

    Wu, Qijun; Wang, Lufei; Zu, Lily

    2011-01-01

    We report the design and operation of a Virtual Instrument (VI) system based on LabVIEW 2009 for laser-induced fluorescence experiments. This system achieves synchronous control of equipment and acquisition of real-time fluorescence data communicating with a single computer via GPIB, USB, RS232, and parallel ports. The reported VI system can also accomplish data display, saving, and analysis, and printing the results. The VI system performs sequences of operations automatically, and this system has been successfully applied to obtain the excitation and dispersion spectra of α-methylnaphthalene. The reported VI system opens up new possibilities for researchers and increases the efficiency and precision of experiments. The design and operation of the VI system are described in detail in this paper, and the advantages that this system can provide are highlighted.

  5. Detecting long-term low-irradiance stress and water stress of trees with laser-induced fluorescence measurements

    International Nuclear Information System (INIS)

    Sagawa, M.; Kurata, K.; Takahashi, K.; Mineuchi, K.

    2001-01-01

    The objective of this study was to find simple and objective methods of diagnosing the ailments of trees in indoor spaces, such as atriums. In this study, two simple diagnostics were compared. One was the analysis of the laser-induced fluorescence spectra of leaves and the other was the analysis of the laser-induced chlorophyll-fluorescence induction kinetics (Kautsky effect). In the latter analysis, second time derivatives of the induction-kinetics curves were used. Cinnamomum camphora and Quercus myrsinifolia grown under different light conditions and Cinnamomum camphora under water stress were used in the experiments. The effects of low irradiance were detected in both the induction kinetics and the spectra; however, the effects of water stress were detected in the induction kinetics only. These results indicate the possibility of utilizing laser-induced-fluorescence induction-kinetics for diagnosing the ailments of trees. (author)

  6. Detection of bacterial infection of agave plants by laser-induced fluorescence

    Science.gov (United States)

    Cervantes-Martinez, Jesus; Flores-Hernandez, Ricardo; Rodriguez-Garay, Benjamin; Santacruz-Ruvalcaba, Fernando

    2002-05-01

    Greenhouse-grown plants of Agave tequilana Weber var. azul were inoculated with Erwinia carotovora, the causal agent of stem soft rot. We investigated the laser-induced fluorescence (LIF) of agave plants to determine whether LIF can be used as a noninvasive sensing tool for pathological studies. The LIF technique was also investigated as a means of detecting the effect of the polyamine biosynthesis inhibitor beta-hydroxyethylhydrazine as a bactericide against the pathogenic bacterium Erwinia carotovora. A He-Ne laser at 632.8 nm was used as the excitation source, and in vivo fluorescence emission spectra were recorded in the 660-790-range. Fluorescence maxima were at 690 and 740 nm. The infected plants that were untreated with the bactericide showed a definite increase in fluorescence intensity at both maxima within the first three days after infection. Beginning on the fifth day, a steady decrease in fluorescence intensity was observed, with a greater effect at 740 than at 690 nm. After 30 days there was no fluorescence. The infected plants that had been treated with the bactericide showed no significant change in fluorescence compared with that of the uninfected plants. The ratio of fluorescence intensities was determined to be F 690 nm/F 740 nm for all treatments. These studies indicate that LIF measurements of agave plants may be used for the early detection of certain types of disease and for determining the effect of a bactericide on bacteria. The results also showed that fluorescence intensity ratios can be used as a reliable indicator of the progress of disease.

  7. Quantitative liquid and vapor distribution measurements in evaporating fuel sprays using laser-induced exciplex fluorescence

    International Nuclear Information System (INIS)

    Fansler, Todd D; Drake, Michael C; Gajdeczko, Boguslaw; Düwel, Isabell; Koban, Wieland; Zimmermann, Frank P; Schulz, Christof

    2009-01-01

    Fully quantitative two-dimensional measurements of liquid- and vapor-phase fuel distributions (mass per unit volume) from high-pressure direct-injection gasoline injectors are reported for conditions of both slow and rapid vaporization in a heated, high-pressure spray chamber. The measurements employ the coevaporative gasoline-like fluorobenzene (FB)/diethylmethylamine (DEMA)/hexane exciplex tracer/fuel system. In contrast to most previous laser-induced exciplex-fluorescence (LIEF) experiments, the quantitative results here include regions in which liquid and vapor fuel coexist (e.g. near the injector exit). A unique aspect is evaluation of both vapor- and liquid-phase distributions at varying temperature and pressure using only in situ vapor-phase fluorescence calibration measurements at room temperature and atmospheric pressure. This approach draws on recent extensive measurements of the temperature-dependent spectroscopic properties of the FB–DEMA exciplex system, in particular on knowledge of the quantum efficiencies of the vapor-phase and liquid-phase (exciplex) fluorescence. In addition to procedures necessary for quantitative measurements, we discuss corrections for liquid–vapor crosstalk (liquid fluorescence that overlaps the vapor-fluorescence bandpass), the unknown local temperature due to vaporization-induced cooling, and laser-sheet attenuation by scattering and absorption

  8. Review of laser-induced fluorescence methods for measuring rf- and microwave electric fields in discharges

    International Nuclear Information System (INIS)

    Gavrilenko, V.; Oks, E.

    1994-01-01

    Development of methods for measuring rf- or μ-wave electric fields E(t) = E 0 cosωt in discharge plasmas is of a great practical importance. First, these are fields used for producing rf- or μ-wave discharges. Second, the fields E(t) may represent electromagnetic waves penetrating into a plasma from the outside. This paper reviews methods for diagnostics of the fields E(t) in low temperature plasmas based on Laser-Induced Fluorescence (LIF). Compared to emission (passive) methods, LIF-methods have a higher sensitivity as well as higher spatial and temporal resolutions. Underlying physical effects may be highlighted by an example of LIF of hydrogen atoms in a plasma. After a presentation of the underlying physical principles, the review focuses on key experiments where these principles were implemented for measurements of rf- and μ-wave electric fields in various discharges

  9. Thermal characterization of a flashing jet by planar laser-induced fluorescence

    Science.gov (United States)

    Vetrano, M. R.; Simonini, A.; Steelant, J.; Rambaud, P.

    2013-07-01

    Flash atomization can be observed when a pressurized fluid is released in an environment at lower pressure. This phenomenon plays an important role in the security management of chemical industries where liquefied gases can be accidentally released at atmosphere. In other applications, for example in propulsion systems, it can have some potential benefits as it is known to produce a fine spray with enhanced atomization. The experimental characterization of these kinds of atomization should be performed by means of non-intrusive measurement techniques since they are very sensitive to external perturbation. In this work, the planar laser-induced fluorescence technique is used to measure the liquid phase temperature of an ethanol superheated flashing jet. The feasibility of the technique is proved, measurements are taken for different superheat conditions, and an analysis of the measurement uncertainties is presented.

  10. Parallel ion flow velocity measurement using laser induced fluorescence method in an electron cyclotron resonance plasma

    International Nuclear Information System (INIS)

    Yoshimura, Shinji; Okamoto, Atsushi; Terasaka, Kenichiro; Ogiwara, Kohei; Tanaka, Masayoshi Y.; Aramaki, Mitsutoshi

    2010-01-01

    Parallel ion flow velocity along a magnetic field has been measured using a laser induced fluorescence (LIF) method in an electron cyclotron resonance (ECR) argon plasma with a weakly-diverging magnetic field. To measure parallel flow velocity in a cylindrical plasma using the LIF method, the laser beam should be injected along device axis; however, the reflection of the incident beam causes interference between the LIF emission of the incident and reflected beams. Here we present a method of quasi-parallel laser injection at a small angle, which utilizes the reflected beam as well as the incident beam to obtain the parallel ion flow velocity. Using this method, we observed an increase in parallel ion flow velocity along the magnetic field. The acceleration mechanism is briefly discussed on the basis of the ion fluid model. (author)

  11. Assisted Interpretation of Laser-Induced Fluorescence Spectra of Egg-Based Binding Media Using Total Emission Fluorescence Spectroscopy

    International Nuclear Information System (INIS)

    Anglos, D.; Nevin, A.

    2006-01-01

    Laser-induced fluorescence (LIF) spectroscopy can provide nondestructive, qualitative analysis of protein-based binding media found in artworks. Fluorescence emissions from proteins in egg yolk and egg white are due to auto fluorescent aromatic amino acids as well as other native and age-related fluorophores, but the potential of fluorescence spectroscopy for the differentiation between binding media is dependent on the choice of a suitable excitation wavelength and limited by problems in interpretation. However, a better understanding of emission spectra associated with LIF can be achieved following comparisons with total emission fluorescence spectra where a series of consecutive emission spectra are recorded over a specific range. Results using nanosecond UV laser sources for LIF of egg-based binding media are presented which are rationalised following comparisons with total emission spectra. Specifically, fluorescence is assigned to tryptophan and oxidation products of amino acids; in the case of egg yolk, fatty-acid polymerisation and age-related degradation products account for the formation of fluorophores.

  12. Determination of absolute Ba densities during dimming operation of fluorescent lamps by laser-induced fluorescence measurements

    International Nuclear Information System (INIS)

    Hadrath, S; Beck, M; Garner, R C; Lieder, G; Ehlbeck, J

    2007-01-01

    Investigations of fluorescent lamps (FL) are often focused on the electrodes, since the lifetime of the lamps is typically limited by the electrode lifetime and durability. During steady state operation, the work function lowering emitter material, in particular, barium, is lost. Greater barium losses occur under dimming conditions, in which reduced discharge currents lead to increased cathode falls, the result of the otherwise diminished heating of the electrode by the bombarding plasma ions. In this work the barium density near the electrodes of (FL), operating in high frequency dimming mode is investigated using the high-sensitivity method of laser-induced fluorescence. From these measurements we infer barium loss for a range of discharge currents and auxiliary coil heating currents. We show that the Ba loss can very easily be reduced by moderate auxiliary coil heating

  13. Sensitive determination of malondialdehyde in exhaled breath condensate and biological fluids by capillary electrophoresis with laser induced fluorescence detection

    Czech Academy of Sciences Publication Activity Database

    Lačná, J.; Foret, František; Kubáň, Petr

    2017-01-01

    Roč. 169, JUL (2017), s. 85-90 ISSN 0039-9140 Grant - others:GA ČR(CZ) GA13-21919S Keywords : malondialdehyde * capillary electrophoresis * laser induced fluorescence * blood plasma * saliva Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 4.162, year: 2016

  14. A vacuum-UV laser-induced fluorescence experiment for measurement of rotationally and vibrationally excited H2

    NARCIS (Netherlands)

    Vankan, P.J.W.; Heil, S.B.S.; Mazouffre, S.; Engeln, R.A.H.; Schram, D.C.; Döbele, H.F.

    2004-01-01

    An experimental setup is built to detect spatially resolved rovibrationally excited hydrogen molecules via laser-induced fluorescence. To excite the hydrogen molecules, laser radiation is produced in the vacuum UV part of the spectrum. The laser radiation is tunable between 120 nm and 230 nm and has

  15. Ultraviolet laser-induced fluorescence detection strategies in capillary electrophoresis: determination of naphthalene sulphonates in river water.

    NARCIS (Netherlands)

    Kok, S.J.; Isberg, I.C.K.; Gooijer, C.; Brinkman, U.A.T.; Velthorst, N.H.

    1998-01-01

    Various UV-laser-induced fluorescence detection strategies for capillary electrophoresis (CE) are compared, i.e. two UV-laser systems (a pulsed laser providing up to 25 mW of tunable emission, applied at 280, 290 and 325 nm, and a continuous wave (cw) laser providing up to 100 mW of 257 nm emission)

  16. Toluene laser-induced fluorescence imaging of compressible flows in an expansion tube

    Science.gov (United States)

    Miller, V. A.; Gamba, M.; Mungal, M. G.; Hanson, R. K.; Mohri, K.; Schulz, C.

    2011-11-01

    Laser-induced fluorescence (LIF) imaging using toluene as a tracer molecule has been developed for high-speed, low-to-moderate enthalpy conditions in the Stanford 6-inch Expansion Tube. The approach is demonstrated on three canonical compressible flow configurations: (i) supersonic flow over a 20° wedge, (ii) around a cylinder, and (iii) a supersonic boundary layer. Under constant-pressure conditions, toluene LIF offers unique sensitivity to temperature and can therefore be used as an accurate thermometry diagnostic for supersonic flows; on the other hand, for variable-pressure flow fields (e.g., flow around a blunt body), toluene LIF imaging is demonstrated to be an effective flow visualization tool. The three configurations selected demonstrate the diagnostic in these two capacities. For all configurations considered in the study, toluene (0.6% by volume) is seeded into a nitrogen freestream at a Mach number ~ 2.2, T ~ 500K, and p ~ 1.5 bar. A frequency-quadrupled pulsed Nd:YAG laser is used to excite the tracer, and the resulting fluorescence is captured by an ICCD camera. Synthetic fluorescence signals from CFD solutions of each case have been computed and compare favorably to measured signals. Sponsored by DoE PSAAP at Stanford University.

  17. Laser Induced Fluorescence Spectroscopy of Neutral and Ionized Polycyclic Aromatic Hydrocarbons in the Cosmic Simulation Chamber

    Science.gov (United States)

    Bejaoui, Salma; Salama, Farid; Contreras, Cesar; Sciamma O'Brien, Ella; Foing, Bernard; Pascale, Ehrenfreund

    2015-01-01

    Polycyclic aromatic hydrocarbon (PAH) molecules are considered the best carriers to account for the ubiquitous infrared emission bands. PAHs have also been proposed as candidates to explain the diffuse interstellar bands (DIBs), a series of absorption features seen on the interstellar extinction curve and are plausible carriers for the extended red emission (ERE), a photoluminescent process associated with a wide variety of interstellar environments. Extensive efforts have been devoted over the past two decades to characterize the physical and chemical properties of PAH molecules and ions in space. Absorption spectra of PAH molecules and ions trapped in solid matrices have been compared to the DIBs. Absorption spectra of several cold, isolated gas-phase PAHs have also been measured under experimental conditions that mimic the interstellar conditions. The purpose of this study is to provide a new dimension to the existing spectroscopic database of neutral and single ionized PAHs that is largely based on absorption spectra by adding emission spectroscopy data. The measurements are based on the laser induced fluorescence (LIF) technique and are performed with the Pulsed Discharge Nozzle (PDN) of the COSmIC laboratory facility at NASA Ames laboratory. The PDN generates a plasma in a free supersonic jet expansion to simulate the physical and the chemical conditions in interstellar environments. We focus, here, on the fluorescence spectra of large neutral PAHs and their cations where there is a lack of fluorescence spectroscopy data. The astronomical implications of the data (e.g., ERE) are examined.

  18. Use of a laser-induced fluorescence thermal imaging system for film cooling heat transfer measurement

    Energy Technology Data Exchange (ETDEWEB)

    Chyu, M.K. [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    1995-10-01

    This paper describes a novel approach based on fluorescence imaging of thermographic phosphor that enables the simultaneous determination of both local film effectiveness and local heat transfer on a film-cooled surface. The film cooling model demonstrated consists of a single row of three discrete holes on a flat plate. The transient temperature measurement relies on the temperature-sensitive fluorescent properties of europium-doped lanthanum oxysulfide (La{sub 2}O{sub 2}S:EU{sup 3+}) thermographic phosphor. A series of full-field surface temperatures, mainstream temperatures, and coolant film temperatures were acquired during the heating of a test surface. These temperatures are used to calculate the heat transfer coefficients and the film effectiveness simultaneously. Because of the superior spatial resolution capability for the heat transfer data reduced from these temperature frames, the laser-induced fluorescence (LIF) imaging system, the present study observes the detailed heat transfer characteristics over a film-protected surface. The trend of the results agrees with those obtained using other conventional thermal methods, as well as the liquid crystal imaging technique. One major advantage of this technique is the capability to record a large number of temperature frames over a given testing period. This offers multiple-sample consistency.

  19. Differential laser-induced perturbation spectroscopy and fluorescence imaging for biological and materials sensing

    Science.gov (United States)

    Burton, Dallas Jonathan

    The field of laser-based diagnostics has been a topic of research in various fields, more specifically for applications in environmental studies, military defense technologies, and medicine, among many others. In this dissertation, a novel laser-based optical diagnostic method, differential laser-induced perturbation spectroscopy (DLIPS), has been implemented in a spectroscopy mode and expanded into an imaging mode in combination with fluorescence techniques. The DLIPS method takes advantage of deep ultraviolet (UV) laser perturbation at sub-ablative energy fluences to photochemically cleave bonds and alter fluorescence signal response before and after perturbation. The resulting difference spectrum or differential image adds more information about the target specimen, and can be used in combination with traditional fluorescence techniques for detection of certain materials, characterization of many materials and biological specimen, and diagnosis of various human skin conditions. The differential aspect allows for mitigation of patient or sample variation, and has the potential to develop into a powerful, noninvasive optical sensing tool. The studies in this dissertation encompass efforts to continue the fundamental research on DLIPS including expansion of the method to an imaging mode. Five primary studies have been carried out and presented. These include the use of DLIPS in a spectroscopy mode for analysis of nitrogen-based explosives on various substrates, classification of Caribbean fruit flies versus Caribbean fruit flies that have been irradiated with gamma rays, and diagnosis of human skin cancer lesions. The nitrogen-based explosives and Caribbean fruit flies have been analyzed with the DLIPS scheme using the imaging modality, providing complementary information to the spectroscopic scheme. In each study, a comparison between absolute fluorescence signals and DLIPS responses showed that DLIPS statistically outperformed traditional fluorescence techniques

  20. Development of laser-induced fluorescence for precombustion diagnostics in spark-ignition engines

    Energy Technology Data Exchange (ETDEWEB)

    Neij, H.

    1998-11-01

    Motivated by a desire to understand and optimize combustion in spark-ignition (SI) engines, laser techniques have been developed for measurement of fuel and residual gas, respectively, in the precombustion mixture of an operating SI engine. The primary objective was to obtain two-dimensional, quantitative data in the vicinity of the spark gap at the time of ignition. A laser-induced fluorescence (LIF) technique was developed for fuel visualization in engine environments. Since the fluorescence signal from any commercial gasoline fuel would be unknown to its origin, with an unpredictable dependence on collisional partners, pressure and temperature, a non-fluorescent base fuel - isooctane - was used. For LIF detection, a fluorescent species was added to the fuel. An additive not commonly used in this context - 3-pentanone - was chosen based on its suitable vaporization characteristics and fluorescent properties. The LIF technique was applied to an optically accessible research engine. By calibration, the fluorescence signal from the additive was converted to fuel-to-air equivalence ratio ({phi}). The accuracy and precision of the acquired data were assessed. A statistical evaluation revealed that the spatially averaged equivalence ratio around the spark plug had a significant impact on the combustion event. The strong correlation between these two quantities suggested that the early combustion was sensitive to large-scale inhomogeneities in the precombustion mixture. A similar LIF technique, using acetone as a fluorescent additive in methane, was applied to a combustion cell for ion current evaluation. The local equivalence ratio around the spark gap at the time of ignition was extracted from LIF data. Useful relations were identified between different ion current parameters and the local equivalence ratio, although the impact of the flow field, the fuel type, and the electrode geometry were identified as areas for future research. A novel fuel - dimethyl ether (DME

  1. Analysis of discrete and continuous laser induced fluorescence spectra of the A 1Σsub(u)+-X 1Σsub(g)+ band system of Sr2

    International Nuclear Information System (INIS)

    Gerber, G.; Moeller, R.

    1982-01-01

    Laser induced fluorescence spectra of the gaseous Sr 2 excimer molecule have been measured. The spectra contain discrete molecular fluorescence series, regularly modulated continuous fluorescence and an unstructured continuum. Analysis of the molecular line spectra yields for the first time Dunham coefficients for the X 1 Σsub(g) + ground state and the A 1 Σsub(u) + excited state. Using the intensity distribution of the modulated continuum which is associated with bound-free transitions the repulsive potential of the ground state up to 3000 cm -1 above the dissociation limit has been determined. The unstructured continuum can be analyzed as due to two types of continuous fluorescence. The dissociation energy of Sr 2 has been determined to Dsub(e)(X) = 965 +- 45 cm -1 . (Auth.)

  2. Analysis of discrete and continuous laser induced fluorescence spectra of the A 1μ+sub(u) - X 1μ+sub(g) band system of SR2

    International Nuclear Information System (INIS)

    Gerber, G.; Moeller, R.

    1982-01-01

    Laser induced fluorescence spectra of the gaseous Sr 2 excimer molecule have been measured. The spectra contain discrete molecular fluorescence series, regularly modulated continuous fluorescence and an unstructured continuum. Analysis of the molecular line spectra yields for the first time Dunham coefficients for the X 1 μ + sub(g) ground state and the A 1 μ + sub(u) excited state. Using the intensity distribution of the modulated continuum which is associated with bound-free transitions the repulsive potential of the ground state up to 3000 cm - 1 above the dissociation limit has been determined. The unstructured continuum can be analyzed as due to two types of continuous fluorescence. The dissociation energy of Sr 2 has been determined to Dsub(e) (X) = 965 +- 45 cm - 1 . (Author)

  3. Separation and identification of DNA-carcinogen adduct conformers by polyacrylamide gel electrophoresis with laser-induced fluorescence detection

    Energy Technology Data Exchange (ETDEWEB)

    Marsch, G.A.; Jankowiak, R.; Farhat, J.H.; Small, G.J. (Ames Lab., IA (United States) Iowa State Univ., Ames (United States))

    1992-12-01

    The authors have developed a separation protocol utilizing high-resolution polyacrylamide gel electrophoresis (PAGE) to isolate stable anti-benzo[a]pyrene diol epoxide adducts of oligodeoxynucleotides. Both enantiomers produced multiple adduct species. The distribution of adduct types could be quantitated by densitometry of autoradiograms or Cerenkov counting of eluted oligomers modified by anti-BPDE isomers. Laser-induced fluorescence (LIF) spectra of eluted adducts at 4.2 K (fluorescence line-narrowing spectroscopy) and 77 K revealed that bands corresponded to pure conformers of pyrene chromophore. Carcinogen-modified oligodeoxynucleotides were single-stranded, but there were often considerable stacking interactions between the pyrenyl residues and the oligonucleotide bases, indicating that electrophoresed oligomers were single-stranded but in a native, versus random-coil conformation. The ability to identify and quantitate adducts by PAGE-LIF, coupled with the high resolution and sensitivity of both techniques, makes PAGE and LIF in tandem a potentially powerful tool in the study of chemical carcinogenesis or other ligand-DNA interactions. 43 refs., 7 figs., 1 tab.

  4. A simple dental caries detection system using full spectrum of laser-induced fluorescence

    Science.gov (United States)

    Rocha-Cabral, Renata Maciel; Mendes, Fausto Medeiros; Maldonado, Edison Puig; Zezell, Denise Maria

    2015-06-01

    Objectives: to develop an apparatus for the detection of early caries lesions in enamel using the full extent of the tooth fluorescence spectrum, through the integration of a laser diode, fiber optics, filters and one portable spectrometer connected to a computer, all commercially available; to evaluate the developed device in clinical and laboratory tests, and compare its performance with commercial equipment. Methods: clinical examinations were performed in patients with indication for exodontics of premolars. After examinations, the patients underwent surgery and the teeth were stored individually. The optical measurements were repeated approximately two months after extraction, on the same sites previously examined, then histological analysis was carried out. Results: the spectral detector has presented high specificity and moderate sensitivity when applied to differentiate between healthy and damaged tissues, with no significant differences from the performance of the commercial equipment. The developed device is able to detect initial damages in enamel, with depth of approximately 300 μm. Conclusions: we successfully demonstrated the development of a simple and portable system based in laser-induced fluorescence for caries detection, assembled from common commercial parts. As the spectral detector acquires a complete recording of the spectrum from each tissue, it is possible to use it for monitoring developments of caries lesions.

  5. Portable detection system of vegetable oils based on laser induced fluorescence

    Science.gov (United States)

    Zhu, Li; Zhang, Yinchao; Chen, Siying; Chen, He; Guo, Pan; Mu, Taotao

    2015-11-01

    Food safety, especially edible oils, has attracted more and more attention recently. Many methods and instruments have emerged to detect the edible oils, which include oils classification and adulteration. It is well known than the adulteration is based on classification. Then, in this paper, a portable detection system, based on laser induced fluorescence, is proposed and designed to classify the various edible oils, including (olive, rapeseed, walnut, peanut, linseed, sunflower, corn oils). 532 nm laser modules are used in this equipment. Then, all the components are assembled into a module (100*100*25mm). A total of 700 sets of fluorescence data (100 sets of each type oil) are collected. In order to classify different edible oils, principle components analysis and support vector machine have been employed in the data analysis. The training set consisted of 560 sets of data (80 sets of each oil) and the test set consisted of 140 sets of data (20 sets of each oil). The recognition rate is up to 99%, which demonstrates the reliability of this potable system. With nonintrusive and no sample preparation characteristic, the potable system can be effectively applied for food detection.

  6. 3D ion velocity distribution function measurement in an electric thruster using laser induced fluorescence tomography

    Science.gov (United States)

    Elias, P. Q.; Jarrige, J.; Cucchetti, E.; Cannat, F.; Packan, D.

    2017-09-01

    Measuring the full ion velocity distribution function (IVDF) by non-intrusive techniques can improve our understanding of the ionization processes and beam dynamics at work in electric thrusters. In this paper, a Laser-Induced Fluorescence (LIF) tomographic reconstruction technique is applied to the measurement of the IVDF in the plume of a miniature Hall effect thruster. A setup is developed to move the laser axis along two rotation axes around the measurement volume. The fluorescence spectra taken from different viewing angles are combined using a tomographic reconstruction algorithm to build the complete 3D (in phase space) time-averaged distribution function. For the first time, this technique is used in the plume of a miniature Hall effect thruster to measure the full distribution function of the xenon ions. Two examples of reconstructions are provided, in front of the thruster nose-cone and in front of the anode channel. The reconstruction reveals the features of the ion beam, in particular on the thruster axis where a toroidal distribution function is observed. These findings are consistent with the thruster shape and operation. This technique, which can be used with other LIF schemes, could be helpful in revealing the details of the ion production regions and the beam dynamics. Using a more powerful laser source, the current implementation of the technique could be improved to reduce the measurement time and also to reconstruct the temporal evolution of the distribution function.

  7. Two dimensional laser induced fluorescence in the gas phase: a spectroscopic tool for studying molecular spectroscopy and dynamics

    Science.gov (United States)

    Gascooke, Jason R.; Lawrance, Warren D.

    2017-11-01

    Two dimensional laser induced fluorescence (2D-LIF) extends the usual laser induced fluorescence technique by adding a second dimension, the wavelength at which excited states emit, thereby significantly enhancing the information that can be extracted. It allows overlapping absorption features, whether they arise from within the same molecule or from different molecules in a mixture, to be associated with their appropriate "parent" state and/or molecule. While the first gas phase version of the technique was published a decade ago, the technique is in its infancy, having been exploited by only a few groups to date. However, its potential in gas phase spectroscopy and dynamics is significant. In this article we provide an overview of the technique and illustrate its potential with examples, with a focus on those utilising high resolution in the dispersed fluorescence dimension.

  8. Laser-Induced Fluorescence Detection in High-Throughput Screening of Heterogeneous Catalysts and Single Cells Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Su, Hui [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    Laser-induced fluorescence detection is one of the most sensitive detection techniques and it has found enormous applications in various areas. The purpose of this research was to develop detection approaches based on laser-induced fluorescence detection in two different areas, heterogeneous catalysts screening and single cell study. First, the author introduced laser-induced imaging (LIFI) as a high-throughput screening technique for heterogeneous catalysts to explore the use of this high-throughput screening technique in discovery and study of various heterogeneous catalyst systems. This scheme is based on the fact that the creation or the destruction of chemical bonds alters the fluorescence properties of suitably designed molecules. By irradiating the region immediately above the catalytic surface with a laser, the fluorescence intensity of a selected product or reactant can be imaged by a charge-coupled device (CCD) camera to follow the catalytic activity as a function of time and space. By screening the catalytic activity of vanadium pentoxide catalysts in oxidation of naphthalene, they demonstrated LIFI has good detection performance and the spatial and temporal resolution needed for high-throughput screening of heterogeneous catalysts. The sample packing density can reach up to 250 x 250 subunits/cm2 for 40-μm wells. This experimental set-up also can screen solid catalysts via near infrared thermography detection. In the second part of this dissertation, the author used laser-induced native fluorescence coupled with capillary electrophoresis (LINF-CE) and microscope imaging to study the single cell degranulation. On the basis of good temporal correlation with events observed through an optical microscope, they have identified individual peaks in the fluorescence electropherograms as serotonin released from the granular core on contact with the surrounding fluid.

  9. Ultra-sensitive high performance liquid chromatography-laser-induced fluorescence based proteomics for clinical applications.

    Science.gov (United States)

    Patil, Ajeetkumar; Bhat, Sujatha; Pai, Keerthilatha M; Rai, Lavanya; Kartha, V B; Chidangil, Santhosh

    2015-09-08

    An ultra-sensitive high performance liquid chromatography-laser induced fluorescence (HPLC-LIF) based technique has been developed by our group at Manipal, for screening, early detection, and staging for various cancers, using protein profiling of clinical samples like, body fluids, cellular specimens, and biopsy-tissue. More than 300 protein profiles of different clinical samples (serum, saliva, cellular samples and tissue homogenates) from volunteers (normal, and different pre-malignant/malignant conditions) were recorded using this set-up. The protein profiles were analyzed using principal component analysis (PCA) to achieve objective detection and classification of malignant, premalignant and healthy conditions with high sensitivity and specificity. The HPLC-LIF protein profiling combined with PCA, as a routine method for screening, diagnosis, and staging of cervical cancer and oral cancer, is discussed in this paper. In recent years, proteomics techniques have advanced tremendously in life sciences and medical sciences for the detection and identification of proteins in body fluids, tissue homogenates and cellular samples to understand biochemical mechanisms leading to different diseases. Some of the methods include techniques like high performance liquid chromatography, 2D-gel electrophoresis, MALDI-TOF-MS, SELDI-TOF-MS, CE-MS and LC-MS techniques. We have developed an ultra-sensitive high performance liquid chromatography-laser induced fluorescence (HPLC-LIF) based technique, for screening, early detection, and staging for various cancers, using protein profiling of clinical samples like, body fluids, cellular specimens, and biopsy-tissue. More than 300 protein profiles of different clinical samples (serum, saliva, cellular samples and tissue homogenates) from healthy and volunteers with different malignant conditions were recorded by using this set-up. The protein profile data were analyzed using principal component analysis (PCA) for objective

  10. Evaluation of a tungsten coil atomization-laser-induced fluorescence detection approach for trace elemental analysis

    International Nuclear Information System (INIS)

    Ezer, Muhsin; Elwood, Seth A.; Jones, Bradley T.; Simeonsson, Josef B.

    2006-01-01

    The analytical utility of a tungsten (W)-coil atomization-laser-induced fluorescence (LIF) approach has been evaluated for trace level measurements of elemental chromium (Cr), arsenic (As), selenium (Se), antimony (Sb), lead (Pb), tin (Sn), copper (Cu), thallium (Tl), indium (In), cadmium (Cd), zinc (Zn) and mercury (Hg). Measurements of As, Cr, In, Se, Sb, Pb, Tl, and Sn were performed by laser-induced fluorescence using a single dye laser operating near 460 nm whose output was converted by frequency doubling and stimulated Raman scattering to wavelengths ranging from 196 to 286 nm for atomic excitation. Absolute limits of detection (LODs) of 1, 0.3, 0.3, 0.2, 1, 6, 1, 0.2 and 0.8 pg and concentration LODs of 100, 30, 30, 20, 100, 600, 100, 20, and 80 pg/mL were achieved for As, Se, Sb, Sn, In, Cu, Cr, Pb and Tl, respectively. Determinations of Hg, Pb, Zn and Cd were performed using two-color excitation approaches and resulted in absolute LODs of 2, 30, 5 and 0.6 pg, respectively, and concentration LODs of 200, 3000, 500 and 60 pg/mL, respectively. The sensitivities achieved by the W-coil LIF approaches compare well with those reported by W-coil atomic absorption spectrometry, graphite furnace atomic absorption spectrometry, and graphite furnace electrothermal atomization-LIF approaches. The accuracy of the approach was verified through the analysis of a multielement reference solution containing Sb, Pb and Tl which each had certified performance acceptance limits of 19.6-20.4 μg/mL. The determined concentrations were 20.05 ± 2.60, 20.70 ± 2.27 and 20.60 ± 2.46 μg/mL, for Sb, Pb and Tl, respectively. The results demonstrate that W-coil LIF provides good analytical performance for trace analyses due to its high sensitivity, linearity, and capability to measure multiple elements using a single tunable laser and suggest that the development of portable W-coil LIF instrumentation using compact, solid-state lasers is feasible

  11. Evaluation of a tungsten coil atomization-laser-induced fluorescence detection approach for trace elemental analysis.

    Science.gov (United States)

    Ezer, Muhsin; Elwood, Seth A; Jones, Bradley T; Simeonsson, Josef B

    2006-06-30

    The analytical utility of a tungsten (W)-coil atomization-laser-induced fluorescence (LIF) approach has been evaluated for trace level measurements of elemental chromium (Cr), arsenic (As), selenium (Se), antimony (Sb), lead (Pb), tin (Sn), copper (Cu), thallium (Tl), indium (In), cadmium (Cd), zinc (Zn) and mercury (Hg). Measurements of As, Cr, In, Se, Sb, Pb, Tl, and Sn were performed by laser-induced fluorescence using a single dye laser operating near 460 nm whose output was converted by frequency doubling and stimulated Raman scattering to wavelengths ranging from 196 to 286 nm for atomic excitation. Absolute limits of detection (LODs) of 1, 0.3, 0.3, 0.2, 1, 6, 1, 0.2 and 0.8 pg and concentration LODs of 100, 30, 30, 20, 100, 600, 100, 20, and 80 pg/mL were achieved for As, Se, Sb, Sn, In, Cu, Cr, Pb and Tl, respectively. Determinations of Hg, Pb, Zn and Cd were performed using two-color excitation approaches and resulted in absolute LODs of 2, 30, 5 and 0.6 pg, respectively, and concentration LODs of 200, 3000, 500 and 60 pg/mL, respectively. The sensitivities achieved by the W-coil LIF approaches compare well with those reported by W-coil atomic absorption spectrometry, graphite furnace atomic absorption spectrometry, and graphite furnace electrothermal atomization-LIF approaches. The accuracy of the approach was verified through the analysis of a multielement reference solution containing Sb, Pb and Tl which each had certified performance acceptance limits of 19.6-20.4 microg/mL. The determined concentrations were 20.05+/-2.60, 20.70+/-2.27 and 20.60+/-2.46 microg/mL, for Sb, Pb and Tl, respectively. The results demonstrate that W-coil LIF provides good analytical performance for trace analyses due to its high sensitivity, linearity, and capability to measure multiple elements using a single tunable laser and suggest that the development of portable W-coil LIF instrumentation using compact, solid-state lasers is feasible.

  12. Stereoscopic Planar Laser-Induced Fluorescence Imaging at 500 kHz

    Science.gov (United States)

    Medford, Taylor L.; Danehy, Paul M.; Jones, Stephen B.; Jiang, N.; Webster, M.; Lempert, Walter; Miller, J.; Meyer, T.

    2011-01-01

    A new measurement technique for obtaining time- and spatially-resolved image sequences in hypersonic flows is developed. Nitric-oxide planar laser-induced fluorescence (NO PLIF) has previously been used to investigate transition from laminar to turbulent flow in hypersonic boundary layers using both planar and volumetric imaging capabilities. Low flow rates of NO were typically seeded into the flow, minimally perturbing the flow. The volumetric imaging was performed at a measurement rate of 10 Hz using a thick planar laser sheet that excited NO fluorescence. The fluorescence was captured by a pair of cameras having slightly different views of the flow. Subsequent stereoscopic reconstruction of these images allowed the three-dimensional flow structures to be viewed. In the current paper, this approach has been extended to 50,000 times higher repetition rates. A laser operating at 500 kHz excites the seeded NO molecules, and a camera, synchronized with the laser and fitted with a beam-splitting assembly, acquires two separate images of the flow. The resulting stereoscopic images provide three-dimensional flow visualizations at 500 kHz for the first time. The 200 ns exposure time in each frame is fast enough to freeze the flow while the 500 kHz repetition rate is fast enough to time-resolve changes in the flow being studied. This method is applied to visualize the evolving hypersonic flow structures that propagate downstream of a discrete protuberance attached to a flat plate. The technique was demonstrated in the NASA Langley Research Center s 31-Inch Mach 10 Air Tunnel facility. Different tunnel Reynolds number conditions, NO flow rates and two different cylindrical protuberance heights were investigated. The location of the onset of flow unsteadiness, an indicator of transition, was observed to move downstream during the tunnel runs, coinciding with an increase in the model temperature.

  13. Study of Sugar Cane Management Systems in Brazil Using Laser Induced Fluorescence

    Science.gov (United States)

    Cabral, Jader; Villas-Boas, Paulino; Carvalho, Camila; Corá, José Eduardo; Milori, Débora

    2014-05-01

    Brazil is the largest producer of cane sugar, consequently, is a leader in the production of bio-ethanol, a clean and renewable energy that fits the model of sustainable economy as discussed and pursued by our society. Our state of São Paulo concentrates 60% of national production, representing a sizeable share in the range of world production. All this economic potential is closely monitored by the scientific community, which develops numerous studies seeking an improvement in production efficiency and reduced environmental impacts caused by the planting. However, the study of soil samples, in plantation areas, demands results about the content and structural forms of organic matter (OM). Also, the soil carbon stocks depend on the type of management. Our goal is to study OM of soil samples from four sugar cane management systems: (i) unburned cane harvest, (ii) preharvest burned, (iii) addition of sugarcane bagasse ash and (iv) addition of residue from the extraction of sucrose, using Laser Induced Fluorescence Spectroscopy of solid state. All the emission spectra were acquired using the system called LIFS-405, which consists of a diode laser Coherent, model cube with excitation at 405 nm, maximum output power of 50mJ and a mini-spectrometer, Ocean Optics USB2000-high sensitivity, with range of 194-894 nm and a fiber-optic bundle design (six excitation fibers in a circular path and one central fiber the collect the fluorescence). In this work, we will present the preliminary results evolving the humification index (HLIFS) of soil OM and total carbon amount (TC) for the different types of management. HLIFS shows a close correlation with the humification index of humic acid in solution obtained by means 2D conventional fluorescence spectroscopy.

  14. Laser-Induced Fluorescence Detection in High-Throughput Screening of Heterogeneous Catalysts and Single Cells Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Su, Hui [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    Laser-induced fluorescence detection is one of the most sensitive detection techniques and it has found enormous applications in various areas. The purpose of this research was to develop detection approaches based on laser-induced fluorescence detection in two different areas, heterogeneous catalysts screening and single cell study. First, we introduced laser-induced imaging (LIFI) as a high-throughput screening technique for heterogeneous catalysts to explore the use of this high-throughput screening technique in discovery and study of various heterogeneous catalyst systems. This scheme is based on the fact that the creation or the destruction of chemical bonds alters the fluorescence properties of suitably designed molecules. By irradiating the region immediately above the catalytic surface with a laser, the fluorescence intensity of a selected product or reactant can be imaged by a charge-coupled device (CCD) camera to follow the catalytic activity as a function of time and space. By screening the catalytic activity of vanadium pentoxide catalysts in oxidation of naphthalene, we demonstrated LIFI has good detection performance and the spatial and temporal resolution needed for high-throughput screening of heterogeneous catalysts. The sample packing density can reach up to 250 x 250 subunits/cm2 for 40-μm wells. This experimental set-up also can screen solid catalysts via near infrared thermography detection.

  15. Laser-Induced Fluorescence Detection in High-Throughput Screening of Heterogeneous Catalysts and Single Cells Analysis

    International Nuclear Information System (INIS)

    Hui Su

    2001-01-01

    Laser-induced fluorescence detection is one of the most sensitive detection techniques and it has found enormous applications in various areas. The purpose of this research was to develop detection approaches based on laser-induced fluorescence detection in two different areas, heterogeneous catalysts screening and single cell study. First, we introduced laser-induced imaging (LIFI) as a high-throughput screening technique for heterogeneous catalysts to explore the use of this high-throughput screening technique in discovery and study of various heterogeneous catalyst systems. This scheme is based on the fact that the creation or the destruction of chemical bonds alters the fluorescence properties of suitably designed molecules. By irradiating the region immediately above the catalytic surface with a laser, the fluorescence intensity of a selected product or reactant can be imaged by a charge-coupled device (CCD) camera to follow the catalytic activity as a function of time and space. By screening the catalytic activity of vanadium pentoxide catalysts in oxidation of naphthalene, we demonstrated LIFI has good detection performance and the spatial and temporal resolution needed for high-throughput screening of heterogeneous catalysts. The sample packing density can reach up to 250 x 250 subunits/cm(sub 2) for 40-(micro)m wells. This experimental set-up also can screen solid catalysts via near infrared thermography detection

  16. Study of Organic Matter in Soils of the Amazon Region Employing Laser Induced Fluorescence Spectroscopy

    Science.gov (United States)

    Tadini, Amanda Maria; Nicolodelli, Gustavo; Mounier, Stéphane; Montes, Célia Regina; Marcondes Bastos Pereira Milori, Débora

    2014-05-01

    In the face of climate change and increasing CO2 levels in the atmosphere, the global carbon cycle, soil organic carbon (SOC) sequestration, and the role of different world biomes as potential sources and sinks of carbon are receiving increasing attention. Carbon quantification is an important environmental indicator, but the structure of organic matter is also important because is related to carbon stability. The synthesis of soil organic matter (SOM), as presented in soils of forest vegetation, can be originated from condensation polymeric polyphenols and quinones that are responsible for controlling the main physical-chemical properties of soils. These systems are present in humic substances, representing the major fluorophore of SOM[1-3]. Abiotic factors, such as soil texture, use and occupation of soil, can influence on the process of SOM formation, molecular structure and in its humification index[4]. Laser Induced Fluorescence Spectroscopy (LIFS) have become a promising technique for assessing humification index of SOM (HLIFS). In this context, the aim of this study was to analyze the humification index of the SOM in the region of Barcelos (Amazon) employing LIFS. The study area was the region of Barcelos, close the river Demeni. The whose vegetation distribution in this area, is two biomes the Dense Ombrophylous Forest (DPQD) and Campinarana (DPQT), with areas of edaphic contacts between these two phytophysiognomies, which ranged from Open field (FDE) to closed Depression (DPQ). Preliminary results showed that the area closed Depression (DPQ) there was a continuous gradient of humification with increasing soil depth. A similar behavior was verified for area Forest (DPQD), where the highest values of HLIFS were obtained between the four points analyzed, indicating the magnitude of the molecular recalcitrance this organic matter in this area. The results obtained for area Campinarana (DPQT) and Open field (FDE) showed an opposite behavior. These points there

  17. X-Ray Fluorescence and Laser-Induced Breakdown Spectroscopy analysis of Roman silver denarii

    Energy Technology Data Exchange (ETDEWEB)

    Pardini, L. [Istituto di Chimica dei Composti Organometallici del CNR, Research Area of Pisa, Via G. Moruzzi 1, 56124 Pisa (Italy); El Hassan, A. [National Institute for Laser- Enhanced Sciences (NILES), Cairo University Giza (Egypt); Ferretti, M. [Istituto per le Tecnologie Applicate ai Beni Culturali, Area della Ricerca del CNR di Montelibretti Roma (Italy); Foresta, A.; Legnaioli, S.; Lorenzetti, G. [Istituto di Chimica dei Composti Organometallici del CNR, Research Area of Pisa, Via G. Moruzzi 1, 56124 Pisa (Italy); Nebbia, E. [Universita degli Studi di Torino (Italy); Catalli, F. [Monetiere di Firenze, Museo Archeologico Nazionale Firenze (Italy); Harith, M.A. [National Institute for Laser- Enhanced Sciences (NILES), Cairo University Giza (Egypt); Diaz Pace, D. [Institute of Physics ' Arroyo Seco' , Faculty of Science, Tandil (Argentina); Anabitarte Garcia, F. [Photonics Engineering Group, University of Cantabria, Santander (Spain); Scuotto, M. [Dipartimento di Scienze Archeologiche, Via Galvani 1, 56126 Pisa (Italy); Palleschi, V., E-mail: vincenzo.palleschi@cnr.it [Istituto di Chimica dei Composti Organometallici del CNR, Research Area of Pisa, Via G. Moruzzi 1, 56124 Pisa (Italy); Dipartimento di Scienze Archeologiche, Via Galvani 1, 56126 Pisa (Italy)

    2012-08-15

    In this paper we present the results of a study performed on a large collection of silver Roman republican denarii, encompassing about two centuries of history. The joint use of Laser-Induced Breakdown Spectroscopy (LIBS) and X-Ray Fluorescence (XRF) spectroscopy allowed for an accurate determination of the coins' elemental composition; the measurements, performed mostly in situ at the 'Monetiere' in Florence, revealed a striking connection between the 'quality' of the silver alloy and some crucial contemporary events. This finding was used to classify a group of denarii whose dating was otherwise impossible. The comparison with other contemporary denarii disproves a recent theory on the origin of the so called 'serrated' denarii (denarii showing notched chisel marks on the edge of the coin). - Highlights: Black-Right-Pointing-Pointer We studied a large collection of Roman republican silver denarii. Black-Right-Pointing-Pointer XRF and LIBS allowed to determine the precious metal content of the coins. Black-Right-Pointing-Pointer A correlation of the 'quality' of the alloy with some contemporary events was found. Black-Right-Pointing-Pointer The study allowed to controvert a recent theory on the so called 'serrated' denarii.

  18. Measurement of fuel corrosion products using planar laser-induced fluorescence

    International Nuclear Information System (INIS)

    Wantuck, P.J.; Sappey, A.D.; Butt, D.P.

    1993-01-01

    Characterizing the corrosion behavior of nuclear fuel material in a high-temperature hydrogen environment is critical for ascertaining the operational performance of proposed nuclear thermal propulsion (NTP) concepts. In this paper, we describe an experimental study undertaken to develop and test non-intrusive, laser-based diagnostics for ultimately measuring the distribution of key gas-phase corrosion products expected to evolve during the exposure of NTP fuel to hydrogen. A laser ablation technique is used to produce high temperature, vapor plumes from uranium-free zirconium carbide (ZrC) and niobium carbide (NbC) forms for probing by various optical diagnostics including planar laser-induced fluorescence (PLIF). We discuss the laser ablation technique, results of plume emission measurements, and we describe both the actual and proposed planar LIF schemes for imaging constituents of the ablated ZrC and NbC plumes. Envisioned testing of the laser technique in rf-heated, high temperature gas streams is also discussed

  19. Development of 2D laser-induced fluorescence (LIF) system in high-density helicon plasma

    International Nuclear Information System (INIS)

    Teshigahara, Naoto; Shinohara, Shunjiro; Kuwahara, Daisuke; Watanabe, Masaki; Yamagata, Yukihiko

    2014-01-01

    Lifetimes of most electric propulsion devices are limited owing to electrode erosion and contamination by plasmas. To overcome this problem, a Helicon Electrodeless Advanced Thruster (HEAT) was proposed by our research team. This scheme employs a high-density (∼10 13 cm -3 ) helicon plasma accelerated by the Lorentz force, which is produced by various acceleration methods. For feasibility of this method, a Laser-Induced Fluorescence (LIF) system was developed. The LIF is a powerful tool for plasma diagnostics because it is a non-invasive method that allows high spatial resolution. Using the LIF, it is possible to deduce velocity distribution functions of different particles (ions, atoms, and molecules). In this paper, we report the details of our novel 2D LIF system as well as some preliminary experimental results. Argon ion velocity distributions at different axial and radial locations were obtained using the novel 2D system. Ion velocity was greatest (∼ 2.8 km/s) at z = -24 cm among all the points measured along the z-axis. Velocity values were approximately 2.7 and 3.2 km/s for radial positions of r = 0 and 3 cm, respectively. Ion temperature values were approximately 0.56 and 0.61 eV at r = 0 and 3 cm, respectively. (author)

  20. Laser-induced-fluorescence studies of fragment ions: CH+ and CD+

    International Nuclear Information System (INIS)

    O'Keefe, A.

    1981-08-01

    The dynamics of ion-molecule interactions within a mass selective rf quadrupole ion trap are studied for several ion-molecule systems. Laser induced fluorescence is used as a probe of the internal energy distributions of molecular ions under collision free conditions and under controlled collision conditions. The effects of collisions at near thermal energies (0.3 to 0.5 eV) are easily understood in terms of processes such as charge transfer and other energy transfer mechanisms. The A 1 PI - X 1 Σ + system of CH + and CD + has been examined under collision free conditions. The ions were produced from methane through electron impact ionization/dissociation. The observed energy distributions reflect the dynamical partitioning of dissociation exothermicity, excepting short lived electronic states. Many new transitions belonging to this electronic system have been observed and a reliable vibrational frequency for the X 1 Σ + state has been obtained. The radiative lifetimes of CH + and CD + A 1 PI(v = 0) states have been measured and a revised oscillator strength for the A-X transition has been derived from this data

  1. Laser Induced Fluorescence Measurements in a Hall Thruster Plume as a Function of Background Pressure

    Science.gov (United States)

    Spektor, R.; Tighe, W. G.; Kamhawi, H.

    2016-01-01

    A set of Laser Induced Fluorescence (LIF) measurements in the near-field region of the NASA- 173M Hall thruster plume is presented at four background pressure conditions varying from 9.4 x 10(exp -6) torr to 3.3 x 10(exp -5) torr. The xenon ion velocity distribution function was measured simultaneously along the axial and radial directions. An ultimate exhaust velocity of 19.6+/-0.25 km/s achieved at a distance of 20 mm was measured, and that value was not sensitive to pressure. On the other hand, the ion axial velocity at the thruster exit was strongly influenced by pressure, indicating that the accelerating electric field moved inward with increased pressure. The shift in electric field corresponded to an increase in measured thrust. Pressure had a minor effect on the radial component of ion velocity, mainly affecting ions exiting close to the channel inner wall. At that radial location the radial component of ion velocity was approximately 1000 m/s greater at the lowest pressure than at the highest pressure. A reduction of the inner magnet coil current by 0.6 A resulted in a lower axial ion velocity at the channel exit while the radial component of ion velocity at the channel inner wall location increased by 1300 m/s, and at the channel outer wall location the radial ion velocity remained unaffected. The ultimate exhaust velocity was not significantly affected by the inner magnet current.

  2. The diagnostic capability of laser induced fluorescence in the characterization of excised breast tissues

    Science.gov (United States)

    Galmed, A. H.; Elshemey, Wael M.

    2017-08-01

    Differentiating between normal, benign and malignant excised breast tissues is one of the major worldwide challenges that need a quantitative, fast and reliable technique in order to avoid personal errors in diagnosis. Laser induced fluorescence (LIF) is a promising technique that has been applied for the characterization of biological tissues including breast tissue. Unfortunately, only few studies have adopted a quantitative approach that can be directly applied for breast tissue characterization. This work provides a quantitative means for such characterization via introduction of several LIF characterization parameters and determining the diagnostic accuracy of each parameter in the differentiation between normal, benign and malignant excised breast tissues. Extensive analysis on 41 lyophilized breast samples using scatter diagrams, cut-off values, diagnostic indices and receiver operating characteristic (ROC) curves, shows that some spectral parameters (peak height and area under the peak) are superior for characterization of normal, benign and malignant breast tissues with high sensitivity (up to 0.91), specificity (up to 0.91) and accuracy ranking (highly accurate).

  3. Behaviour of atomic oxygen in a pulsed dielectric barrier discharge measured by laser-induced fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Ryo [High Temperature Plasma Center, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 227-8568 (Japan); Yamashita, Youta [Department of Electrical Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656 (Japan); Takezawa, Kei [Department of Electrical Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656 (Japan); Oda, Tetsuji [Department of Electrical Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656 (Japan)

    2005-08-21

    Atomic oxygen is measured in a pulsed dielectric barrier discharge (DBD) using two-photon absorption laser-induced fluorescence (TALIF). The ground-level atomic oxygen is excited to the 3p {sup 3}P state by two-photon absorption at 226 nm. Negative (-40 kV) or positive (+30 kV) pulsed DBD occurs in an O{sub 2}-N{sub 2} mixture at atmospheric pressure. The pulse width of the DBD current is approximately 50 ns. The TALIF experiment shows that the decay rate of atomic oxygen increases linearly with O{sub 2} concentration. This result proves that atomic oxygen decays mainly by the third-body reaction, O + O{sub 2} + M {yields} O{sub 3} + M. The rate coefficient of the third-body reaction is estimated to be 2.2 x 10{sup -34} cm{sup 6} s{sup -1} in the negative DBD and 0.89 x 10{sup -34} cm{sup 6} s{sup -1} in the positive DBD. It is shown that the decay rate of atomic oxygen increases linearly with humidity. This can explain the well-known fact that ozone production in DBD is suppressed by increasing humidity.

  4. Confocal laser-induced fluorescence detector for narrow capillary system with yoctomole limit of detection.

    Science.gov (United States)

    Weaver, Mitchell T; Lynch, Kyle B; Zhu, Zaifang; Chen, Huang; Lu, Joann J; Pu, Qiaosheng; Liu, Shaorong

    2017-04-01

    Laser-induced fluorescence (LIF) detectors for low-micrometer and sub-micrometer capillary on-column detection are not commercially available. In this paper, we describe in details how to construct a confocal LIF detector to address this issue. We characterize the detector by determining its limit of detection (LOD), linear dynamic range (LDR) and background signal drift; a very low LOD (~70 fluorescein molecules or 12 yoctomole fluorescein), a wide LDR (greater than 3 orders of magnitude) and a small background signal drift (~1.2-fold of the root mean square noise) are obtained. For detecting analytes inside a low-micrometer and sub-micrometer capillary, proper alignment is essential. We present a simple protocol to align the capillary with the optical system and use the position-lock capability of a translation stage to fix the capillary in position during the experiment. To demonstrate the feasibility of using this detector for narrow capillary systems, we build a 2-μm-i.d. capillary flow injection analysis (FIA) system using the newly developed LIF prototype as a detector and obtain an FIA LOD of 14 zeptomole fluorescein. We also separate a DNA ladder sample by bare narrow capillary - hydrodynamic chromatography and use the LIF prototype to monitor the resolved DNA fragments. We obtain not only well-resolved peaks but also the quantitative information of all DNA fragments. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. A technique for temperature mapping in fluorocarbon plasmas using planar laser-induced fluorescence of CF

    International Nuclear Information System (INIS)

    Steffens, Kristen L.; Sobolewski, Mark A.

    2004-01-01

    Planar laser-induced fluorescence measurements of CF A 2 Σ + -X 2 Π(1,0) were used to determine two-dimensional maps of rotational temperature in CF 4 plasmas. Measured rotational temperatures are expected to be in equilibrium with the gas temperature due to the long chemical lifetime of CF relative to the collision rate. Experiments were performed in the capacitively coupled Gaseous Electronics Conference rf reference cell at pressures from 26.7 Pa (200 mTorr) to 107 Pa (800 mTorr) and powers of 10 to 30 W deposited in the plasma. Temperatures, which ranged from 273±15 K to 480±15 K, were fairly axially symmetric and increased with pressure and power. All plasmas were coolest near the electrodes, which provided a substantial sink for heat in the plasma. Highest temperatures were found at a radial position near the edge of the electrodes. The strong temperature gradients observed in the plasmas can have serious effects on density measurements that probe a single rotational level, as well as on reaction rate constants and interpretation of density gradients. The effects of water-cooling the electrodes and the presence of a silicon wafer on temperature were also measured

  6. Limitations on the use of the planar laser induced exciplex fluorescence technique in diesel sprays

    Energy Technology Data Exchange (ETDEWEB)

    J.M. Desantes; J.V. Pastor; J.M. Pastor; J.E. Julia [Universidad Politecnica de Valencia, Valencia (Spain). CMT Motores Termicos

    2005-12-01

    The Planar Laser Induced Exciplex Fluorescence (PLIEF) technique is widely used to visualize and measure the fuel concentration fields in both liquid and vapor phases of DI Diesel sprays. However, the real limitations of the PLIEF technique in Diesel sprays and the accuracy of the results obtained are still a source of controversy. In this work, a complete methodology for maximum penetration and fuel concentration measurements in evaporating conditions in Diesel sprays has been developed and the reliability of the results obtained has been investigated. The methodology includes new procedures for measuring both liquid and vapor phases, adapting, when necessary, correlations available in the literature for calibration. An experimental matrix of nine test points with different injection pressures and combustion chamber densities has been performed. A critical analysis of the different error sources for proper quantification is made. Results have shown that macroscopic features can be accurately determined using the PLIEF technique, but for fuel concentration measurements special considerations have to be taken into account, particularly in the regions where liquid and vapor coexist. 37 refs., 15 figs., 2 tabs.

  7. Temperature field measurement research in high-speed diesel engine using laser induced fluorescence technology

    Science.gov (United States)

    Liu, Yongfeng; Zhang, You-tong; Gou, Chenhua; Tian, Hongsen

    2008-12-01

    Temperature laser- induced- fluorescence (LIF) 2-D imaging measurements using a new multi-spectral detection strategy are reported for high pressure flames in high-speed diesel engine. Schematic of the experimental set-up is outlined and the experimental data on the diesel engine is summarized. Experiment injection system is a third generation Bosch high-pressure common rail featuring a maximum pressure of 160 MPa. The injector is equipped with a six-hole nozzle, where each hole has a diameter of 0.124 mm. and slightly offset (by 1.0 mm) to the center of the cylinder axis to allow a better cooling of the narrow bridge between the exhaust valves. The measurement system includes a blower, which supplied the intake flow rate, and a prototype single-valve direct injection diesel engine head modified to lay down the swirled-type injector. 14-bit digital CCD cameras are employed to achieve a greater level of accuracy in comparison to the results of previous measurements. The temperature field spatial distributions in the cylinder for different crank angle degrees are carried out in a single direct-injection diesel engine.

  8. Investigation of Gas Seeding for Planar Laser-Induced Fluorescence in Hypersonic Boundary Layers

    Science.gov (United States)

    Arisman, C. J.; Johansen, C. T.; Bathel, B. F.; Danehy, P. M.

    2015-01-01

    Numerical simulations of the gas-seeding strategies required for planar laser-induced fluorescence in a Mach 10 (approximately Mach 8.2 postshock) airflow were performed. The work was performed to understand and quantify the adverse effects associated with gas seeding and to assess various types of seed gas that could potentially be used in future experiments. In prior experiments, NO and NO2 were injected through a slot near the leading edge of a flatplate wedge model used in NASA Langley Research Center's 31 in. Mach 10 air tunnel facility. In this paper, nitric oxide, krypton, and iodine gases were simulated at various injection rates. Simulations showing the deflection of the velocity boundary layer for each of the cases are presented. Streamwise distributions of velocity and concentration boundary-layer thicknesses, as well as vertical distributions of velocity, temperature, and mass distributions, are presented for each of the cases. A comparison between simulated streamwise velocity profiles and experimentally obtained molecular tagging velocimetry profiles using a nitric oxide seeding strategy is performed to verify the influence of such a strategy on the boundary layer. The relative merits of the different seeding strategies are discussed. The results from a custom solver based on OpenFOAM version 2.2.1 are compared against results obtained from ANSYS® Fluent version 6.3.

  9. UV reactor flow visualization and mixing quantification using three-dimensional laser-induced fluorescence.

    Science.gov (United States)

    Gandhi, Varun; Roberts, Philip J W; Stoesser, Thorsten; Wright, Harold; Kim, Jae-Hong

    2011-07-01

    Three-dimensional laser-induced fluorescence (3DLIF) was applied to visualize and quantitatively analyze mixing in a lab-scale UV reactor consisting of one lamp sleeve placed perpendicular to flow. The recirculation zone and the von Karman vortex shedding that commonly occur in flows around bluff bodies were successfully visualized. Multiple flow paths were analyzed by injecting the dye at various heights with respect to the lamp sleeve. A major difference in these pathways was the amount of dye that traveled close to the sleeve, i.e., a zone of higher residence time and higher UV exposure. Paths away from the center height had higher velocities and hence minimal influence by the presence of sleeve. Approach length was also characterized in order to increase the probability of microbes entering the region around the UV lamp. The 3DLIF technique developed in this study is expected to provide new insight on UV dose delivery useful for the design and optimization of UV reactors. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Development of a Laser Induced Fluorescence (LIF) System with a Tunable Diode Laser

    International Nuclear Information System (INIS)

    Woo, Hyun Jong; Do, Jeong Jun; You, Hyun Jong; Choi, Geun Sik; Lee, Myoung Jae; Chung, Kyu Sun

    2005-01-01

    The Laser Induced Fluorescence (LIF) is known as one of the most powerful techniques for measurements of ion velocity distribution function (IVDF) and ion temperature by means of Doppler broadening and Doppler shift. The dye lasers are generally used for LIF system with 611.66 nm (in vac.) for Ar ion, the low power diode laser was also proposed by Severn et al with the wavelength of 664.55 nm and 668.61 nm (in vac.) for Ar ion. Although the diode laser has the disadvantages of low power and small tuning range, it can be used for LIF system at the low temperature plasmas. A tunable diode laser with 668.614 nm of center wavelength and 10 GHz mode hop free tuning region has been used for our LIF system and it can be measured the ion temperature is up to 1 eV. The ion temperature and velocity distribution function have been measured with LaB6 plasma source, which is about 0.23 eV with Ar gas and 2.2 mTorr working pressure

  11. Consolidated Laser-Induced Fluorescence Diagnostic Systems for the NASA Ames Arc Jet Facilities

    Science.gov (United States)

    Grinstead, Jay; Wilder, Michael C.; Porter, Barry; Brown, Jeff; Yeung, Dickson; Battazzo, Steve; Brubaker, Tim

    2016-01-01

    The spectroscopic diagnostic technique of two photon absorption laser-induced fluorescence (TALIF) of atomic species for non-intrusive arc jet flow property measurement was first implemented at NASA Ames in the mid-1990s. Use of TALIF expanded at NASA Ames and to NASA Johnsons arc jet facility in the late 2000s. In 2013-2014, NASA combined the agency's large-scale arc jet test capabilities at NASA Ames. Concurrent with that effort, the agency also sponsored a project to establish two comprehensive LIF diagnostic systems for the Aerodynamic Heating Facility (AHF) and Interaction Heating Facility (IHF) arc jets. The scope of the project enabled further engineering development of the existing IHF LIF system as well as the complete reconstruction of the original AHF LIF system. The updated LIF systems are identical in design and capability. They represent the culmination of over 20 years of development experience in transitioning a specialized laboratory research tool into a measurement system for large-scale, high-demand test facilities. This paper documents the overall system design from measurement requirements to implementation. Representative data from the redeveloped AHF and IHF LIF systems are also presented.

  12. Laser induced fluorescence in nanosecond repetitively pulsed discharges for CO2 conversion

    Science.gov (United States)

    Martini, L. M.; Gatti, N.; Dilecce, G.; Scotoni, M.; Tosi, P.

    2018-01-01

    A CO2 nanosecond repetitively pulsed discharge (NRP) is a harsh environment for laser induced fluorescence (LIF) diagnostics. The difficulties arise from it being a strongly collisional system in which the gas composition, pressure and temperature, have quick and strong variations. The relevant diagnostic problems are described and illustrated through the application of LIF to the measurement of the OH radical in three different discharge configurations, with gas mixtures containing CO2 + H2O. These range from a dielectric barrier NRP with He buffer gas, a less hostile case in which absolute OH density measurement is possible, to an NRP in CO2+H2O, where the full set of drawbacks is at work. In the last case, the OH density measurement is not possible with laser pulses and detector time resolution in the ns time scale. Nevertheless, it is shown that with a proper knowledge of the collisional rate constants involved in the LIF process, a collisional energy transfer-LIF methodology is still applicable to deduce the gas composition from the analysis of LIF spectra.

  13. Behaviour of atomic oxygen in a pulsed dielectric barrier discharge measured by laser-induced fluorescence

    International Nuclear Information System (INIS)

    Ono, Ryo; Yamashita, Youta; Takezawa, Kei; Oda, Tetsuji

    2005-01-01

    Atomic oxygen is measured in a pulsed dielectric barrier discharge (DBD) using two-photon absorption laser-induced fluorescence (TALIF). The ground-level atomic oxygen is excited to the 3p 3 P state by two-photon absorption at 226 nm. Negative (-40 kV) or positive (+30 kV) pulsed DBD occurs in an O 2 -N 2 mixture at atmospheric pressure. The pulse width of the DBD current is approximately 50 ns. The TALIF experiment shows that the decay rate of atomic oxygen increases linearly with O 2 concentration. This result proves that atomic oxygen decays mainly by the third-body reaction, O + O 2 + M → O 3 + M. The rate coefficient of the third-body reaction is estimated to be 2.2 x 10 -34 cm 6 s -1 in the negative DBD and 0.89 x 10 -34 cm 6 s -1 in the positive DBD. It is shown that the decay rate of atomic oxygen increases linearly with humidity. This can explain the well-known fact that ozone production in DBD is suppressed by increasing humidity

  14. Thermal distribution in biological tissue at laser induced fluorescence and photodynamic therapy

    Science.gov (United States)

    Krasnikov, I. V.; Seteikin, A. Yu.; Drakaki, E.; Makropoulou, M.

    2012-03-01

    Laser induced fluorescence spectroscopy and photodynamic therapy (PDT) are techniques currently introduced in clinical applications for visualization and local destruction of malignant tumours as well as premalignant lesions. During the laser irradiation of tissues for the diagnostic and therapeutic purposes, the absorbed optical energy generates heat, although the power density of the treatment light for surface illumination is normally low enough not to cause any significantly increased tissue temperature. In this work we tried to evaluate the utility of Monte Carlo modeling for simulating the temperature fields and the dynamics of heat conduction into the skin tissue under several laser irradiation conditions with both a pulsed UV laser and a continuous wave visible laser beam. The analysis of the results showed that heat is not localized on the surface, but it is collected inside the tissue. By varying the boundary conditions on the surface and the type of the laser radiation (continuous or pulsed) we can reach higher than normal temperature inside the tissue without simultaneous formation of thermally damaged tissue (e.g. coagulation or necrosis zone).

  15. Three-dimensional laser-induced fluorescence measurements of turbulent chemical plumes

    Science.gov (United States)

    True, Aaron; Crimaldi, John

    2017-11-01

    In order to find prey, mates, and suitable habitat, many organisms must navigate through complex chemical plume structures in turbulent flow environments. In this context, we investigate the spatial and temporal structure of chemical plumes released isokinetically into fractal-grid-generated turbulence in an open channel flow. We first utilized particle image velocimetry (PIV) to characterize flow conditions (mean free stream velocities, turbulence intensities, turbulent kinetic energy dissipation rates, Taylor Reynolds numbers). We then implemented a newly developed high-resolution, high-speed, volumetric scanning laser-induced fluorescence (LIF) system for near time-resolved measurements of three-dimensional chemical plume structures. We investigated cases with and without a cylinder wake, and compare statistical (mean, variance, intermittency, probability density functions) and spectral (power spectrum of concentration fluctuations) characteristics of the chemical plume structure. Stretching and folding of complex three-dimensional filament structures during chaotic turbulent mixing is greatly enhanced in the cylinder wake case. In future experiments, we will implement simultaneous PIV and LIF, enabling computation of the covariance of the velocity and chemical concentration fluctuations and thus estimation of turbulent eddy diffusivities. NSF PHY 1555862.

  16. A vacuum-UV laser-induced fluorescence experiment for measurement of rotationally and vibrationally excited H2

    International Nuclear Information System (INIS)

    Vankan, P.; Heil, S.B.S.; Mazouffre, S.; Engeln, R.; Schram, D.C.; Doebele, H.F.

    2004-01-01

    An experimental setup is built to detect spatially resolved rovibrationally excited hydrogen molecules via laser-induced fluorescence. To excite the hydrogen molecules, laser radiation is produced in the vacuum UV part of the spectrum. The laser radiation is tunable between 120 nm and 230 nm and has a bandwith of 0.15 cm -1 . The wavelength of the laser radiation is calibrated by simultaneous recording of the two-photon laser induced fluorescence spectrum of nitric oxide. The excited hydrogen populations are calibrated on the basis of coherent anti-Stokes Raman scattering measurements. A population distribution is measured in the shock region of a pure hydrogen plasma expansion. The higher rotational levels (J>5) show overpopulation compared to a Boltzmann distribution determined from the lower rotational levels (J≤5)

  17. Instantaneous three-dimensional visualization of concentration distributions in turbulent flows with crossed-plane laser-induced fluorescence imaging

    Science.gov (United States)

    Hoffmann, A.; Zimmermann, F.; Scharr, H.; Krömker, S.; Schulz, C.

    2005-01-01

    A laser-based technique for measuring instantaneous three-dimensional species concentration distributions in turbulent flows is presented. The laser beam from a single laser is formed into two crossed light sheets that illuminate the area of interest. The laser-induced fluorescence (LIF) signal emitted from excited species within both planes is detected with a single camera via a mirror arrangement. Image processing enables the reconstruction of the three-dimensional data set in close proximity to the cutting line of the two light sheets. Three-dimensional intensity gradients are computed and compared to the two-dimensional projections obtained from the two directly observed planes. Volume visualization by digital image processing gives unique insight into the three-dimensional structures within the turbulent processes. We apply this technique to measurements of toluene-LIF in a turbulent, non-reactive mixing process of toluene and air and to hydroxyl (OH) LIF in a turbulent methane-air flame upon excitation at 248 nm with a tunable KrF excimer laser.

  18. Measurement of OH radical density in DBD-enhanced premixed burner flame by laser-induced fluorescence

    Science.gov (United States)

    Zaima, Kazunori; Sasaki, Koichi

    2013-09-01

    We examined OH density in DBD-enhanced premixed burner flame by laser-induced fluorescence (LIF). We ignited a premixed flame with CH4 /O2 / Ar mixture using a burner which worked as the ground electrode. The upper part of the flame was covered with a quartz tube, and we attached an aluminum electrode on the outside of the quartz tube. DBD inside the quartz tube was obtained between the aluminum electrode and the burner nozzle. The planar beam from a pulsed tunable laser excited OH in X2 Π (v'' = 0) to A2Σ+ (v' = 0) , and we captured two-dimensional distribution of the LIF intensity using an ICCD camera. We employed three pump lines of Q1(J=4, 8 and 10), and the rotational temperature of OH(X) was deduced from the ratio of the LIF intensities. The total density of OH was obtained from the LIF intensities and the rotational temperature. A principal experimental result was that no remarkable increase was observed in the OH density by the superposition of DBD. The correlation between the pulsed discharge current and the temporal variation of the OH density was not clear, suggesting that the oscillation of the OH density with a small amplitude is related to the transittion time constant between equilibrium and nonequilibrium combustion chemistries.

  19. A rate-equation model for polarized laser-induced fluorescence to measure electric field in glow discharge He plasmas

    International Nuclear Information System (INIS)

    Takiyama, K.; Watanabe, M.; Oda, T.

    1998-01-01

    Possibility of applying polarized laser-induced fluorescence (LIF) spectroscopy for measuring the electric field in a plasma with a large collisional depolarization has been investigated. A rate equation model including the depolarization process was employed to analyze the time evolution of LIF polarization components. The polarized LIF pulse shapes observed in the sheath of a He glow discharge plasma were successfully reproduced, and the electric field distribution was obtained with high accuracy. (author)

  20. Ablation plume structure and dynamics in ambient gas observed by laser-induced fluorescence imaging spectroscopy

    International Nuclear Information System (INIS)

    Miyabe, M.; Oba, M.; Iimura, H.; Akaoka, K.; Khumaeni, A.; Kato, M.; Wakaida, I.

    2015-01-01

    The dynamic behavior of an ablation plume in ambient gas has been investigated by laser-induced fluorescence imaging spectroscopy. The second harmonic beam from an Nd:YAG laser (0.5–6 J/cm 2 ) was focused on a sintered oxide pellet or a metal chip of gadolinium. The produced plume was subsequently intersected with a sheet-shaped UV beam from a dye laser so that time-resolved fluorescence images were acquired with an intensified CCD camera at various delay times. The obtained cross-sectional images of the plume indicate that the ablated ground state atoms and ions of gadolinium accumulate in a hemispherical contact layer between the plume and the ambient gas, and a cavity containing a smaller density of ablated species is formed near the center of the plume. At earlier expansion stage, another luminous component also expands in the cavity so that it coalesces into the hemispherical layer. The splitting and coalescence for atomic plume occur later than those for ionic plume. Furthermore, the hemispherical layer of neutral atoms appears later than that of ions; however, the locations of the layers are nearly identical. This coincidence of the appearance locations of the layers strongly suggests that the neutral atoms in the hemispherical layer are produced as a consequence of three-body recombination of ions through collisions with gas atoms. The obtained knowledge regarding plume expansion dynamics and detailed plume structure is useful for optimizing the experimental conditions for ablation-based spectroscopic analysis. - Highlights: • Ablated ground-state species accumulated in a thin hemispherical boundary layer • Inside the layer, a cavity containing a small density of ablated species was formed. • The hemispherical layers of atoms and ions appeared at a nearly identical location. • The measured intensity peak variation was in good agreement with a model prediction. • We ascribed the dominant process for forming the layer to a three-body recombination

  1. Multispectral imaging system based on laser-induced fluorescence for security applications

    Science.gov (United States)

    Caneve, L.; Colao, F.; Del Franco, M.; Palucci, A.; Pistilli, M.; Spizzichino, V.

    2016-10-01

    The development of portable sensors for fast screening of crime scenes is required to reduce the number of evidences useful to be collected, optimizing time and resources. Laser based spectroscopic techniques are good candidates to this scope due to their capability to operate in field, in remote and rapid way. In this work, the prototype of a multispectral imaging LIF (Laser Induced Fluorescence) system able to detect evidence of different materials on large very crowded and confusing areas at distances up to some tens of meters will be presented. Data collected as both 2D fluorescence images and LIF spectra are suitable to the identification and the localization of the materials of interest. A reduced scan time, preserving at the same time the accuracy of the results, has been taken into account as a main requirement in the system design. An excimer laser with high energy and repetition rate coupled to a gated high sensitivity ICCD assures very good performances for this purpose. Effort has been devoted to speed up the data processing. The system has been tested in outdoor and indoor real scenarios and some results will be reported. Evidence of the plastics polypropylene (PP) and polyethilene (PE) and polyester have been identified and their localization on the examined scenes has been highlighted through the data processing. By suitable emission bands, the instrument can be used for the rapid detection of other material classes (i.e. textiles, woods, varnishes). The activities of this work have been supported by the EU-FP7 FORLAB project (Forensic Laboratory for in-situ evidence analysis in a post blast scenario).

  2. Ultratrace analysis of actinides via coprecipitation/laser-induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Miller, S.M.

    1982-01-01

    Actinides were selectively preconcentrated by coprecipitating each out of solution with a fluoride matrix and calcining each sample at 800 0 C. The fluorescence spectrum of each sample was recorded by illuminating the sample with laser light and detecting fluorescence with either a fluorescence/Raman spectrometer, an infrared spectrometer or in certain cases a filter fluorimeter. Three previously unobserved actinide spectra were recorded. Narrow lines at 546.9 nm, 564.6 nm, and 569.6 nm were found for CaF 2 :PuO 2++ at 10K. CaF 2 :Am + 3 displayed two broadband fluorescent peaks at 625 nm and 746 nm at room temperature and CaF 2 :Pu + 3 possessed a fluorescent peak at 1.22 microns at 10K. Energy transfer was observed in the form of Tb fluorescence quenching in TbF 3 :Pu + 3 when Pu was present in quantities of 10 ppM or more and in the form of Tb fluorescence enhancement in TbF 3 :Am + 3 when 1 ppM or more of Am was present. Careful sample preparation and the use of temporal as well as a spectral discrimination system extended the detection limit of U from 1 ml samples to the subfemtogram level. The fluorescence detection limits for Pu and Am were extended to 0.48 and 0.032 pg/ml. 39 figures, 9 tables

  3. Changes of the laser-induced blue, green and red fluorescence signatures during greening of etiolated leaves of wheat

    International Nuclear Information System (INIS)

    Stober, F.; Lichtenthaler, H.K.

    1992-01-01

    The UV-laser-induced blue, green and red fluorescence-emission spectra were used to characterize the pigment status of etiolated leaves of wheat (Triticum aestivum L.) during a 48 h greening period under white light conditions. Upon UV-light excitation (337 nm) leaves not only show a fluorescence emission in the red spectral region between 650 and 800nm (chlorophyll fluorescence with maxima near 690nm and 735 nm), but also in the blue and green regions between 400 to 570 nm with maxima or shoulders near 450 nm (blue) and 530 nm (green). During greening of etiolated leaves the chlorophyll-fluorescence ratio F690/F735 strongly correlated with the total chlorophyll content and the ratio of the chlorophylls to the carotenoids (a+b/x+c). The ratio of the blue to the green fluorescence F450/F530 was also correlated with the total chlorophyll content and the ratio of chlorophylls to total carotenoids (a+b/x+c). Consequently, there also existed a correlation between the chlorophyll-fluorescence ratio F690/F735 and the ratio of the blue to green fluorescence F450/F530. In contrast, the ratios of the blue to red fluorescences F450/F690 and F450/F735 did not show clear relations to the pigment content of the investigated plants. The particular shape of the UV-laser-induced-fluorescence emission spectra of wheat leaves as well as the dependencies of the fluorescence ratios on the pigment content are due to a partial and differential reabsorption of the emitted fluorescences by the photosynthetic pigments

  4. Photodetection of early cancer by laser-induced fluorescence of a tumor-selective dye: apparatus design and realization

    Science.gov (United States)

    Wagnieres, Georges A.; Depeursinge, Christian D.; Monnier, Philippe; Savary, Jean-Francois; Cornaz, Piet F.; Chatelain, Andre; van den Bergh, Hubert

    1990-07-01

    An apparatus is designed and realized to detect "early" cancer at the surface of the hollow organs in the human body by endoscopic means. The tumor is localized by the laser induced fluorescence of a dye (HPD) which concentrates selectively in the neoplastic tissue after intravenous injection. Fluorescence contrast between the tumor and its normal surroundings is enhanced by subtracting the background autofluorescence which occurs in both types of tissue. This is done by means of 2-color digital images manipulation in real-time. Preliminary clinical tests of the apparatus demonstrated the detection of carcinoma in situ in the esophagus.

  5. On-line iron ore slurry monitoring using laser induced plasma spectroscopy

    International Nuclear Information System (INIS)

    Barrette, L.; Turmel, S.; Boivin, J.-A.; Sabsabi, M.; Martinovic, T.I.; Ouellet, G.

    1999-01-01

    In response to the need for a better control [Lb1] of the various additives used in the iron ore pellet making process, Laser-Induced Plasma Spectroscopy (LIPS) has been tested for the on-line monitoring of Si, AI, Ca, Mg, and C. This work shows that factors such as laser beam focusing, particle size, slurry density and mineralogical composition have to be taken into account to meet precision and accuracy requirements. An internal standardization (peak ratio) and an original multivariate calibration technique based on fuzzy logic concepts [Lb2] are [Lb3] used to minimize the effect of these factors. This paper describes the experimental set-up, the effect of influence factors and the results obtained both in the laboratory and in an iron ore plant. (author)

  6. Measurements of IO in the Tropical Marine Boundary Layer using Laser-Induced Fluorescence Spectroscopy

    Science.gov (United States)

    Walker, H.; Ingham, T.; Heard, D. E.

    2012-12-01

    Halogenated short-lived substances (VSLS) are emitted from the oceans by marine species such as macroalgae and phytoplankton and contribute to halogen loading in the troposphere and lower stratosphere. Transport of halogenated VSLS into the stratosphere occurs mainly in the tropics, where ascending warm air carries them aloft, and leads to catalytic depletion of stratospheric ozone on a global scale and formation of the Antarctic ozone hole. The tropical marine environment is therefore an important region in which to study the effects of these short-lived halogen species on ozone depletion. The SHIVA (Stratospheric Ozone: Halogen Impacts in a Varying Atmosphere) project combines ship-borne, aircraft-based and ground-based measurements in and over the South China Sea and the Sulu Sea, and around the coast of Malaysian Borneo, to reduce uncertainties in the amount of halogenated VSLS reaching the stratosphere, the associated ozone depletion, and the effects of a changing climate on these processes. In this work we present measurements of IO radicals made onboard the German research vessel Sonne during SHIVA, between Singapore and Manila. IO is formed via photolysis of iodine-containing source gases (e.g. I2, CH3I) to produce I atoms, which react with ozone. It is therefore an important species to consider when assessing the impacts of halogen chemistry on ozone depletion. Measurements of IO were made over a two-week period by the University of Leeds Laser-Induced Fluorescence (LIF) instrument, which excites IO radicals at λ ~ 445 nm and detects the resultant fluorescence at λ ~ 512 nm. A suite of supporting gas- and aqueous-phase measurements were also made, including concentrations of halocarbons (e.g. CHBr3, CH3I), trace pollutant gases (e.g. CO, O3, NOx), and biological parameters (e.g. abundance and speciation of phytoplankton). Preliminary data analysis indicates that IO was detected above the instrumental limit of detection (0.3 pptv for a 30 minute averaging

  7. Temperature measurement in a compressible flow field using laser-induced iodine fluorescence

    Science.gov (United States)

    Fletcher, D. G.; Mcdaniel, J. C.

    1987-01-01

    The thermometric capability of a two-line fluorescence technique using iodine seed molecules in air is investigated analytically and verified experimentally in a known steady compressible flow field. Temperatures ranging from 165 to 295 K were measured in the flowfield using two iodine transitions accessed with a 30-GHz dye-laser scan near 543 nm. The effect of pressure broadening on temperature measurement is evaluated.

  8. Development of megahertz laser-induced fluorescence for visualization of turbulence. Final Report

    International Nuclear Information System (INIS)

    Levinton, F.M.

    2003-01-01

    Turbulence is a key factor limiting the performance of fusion devices central to the development of fusion as an economically viable energy source. Laser techniques to visualize the temporal and spatial evolution of turbulence can be a valuable tool to aid in guiding or validating existing theoretical models. The objective of the Phase I and II effort was to determine the feasibility and develop a MegaHertz Alexandrite planar laser-induced fluorescence (PLIF) system for turbulence imaging. The requirements of the laser energy, pulse duration, and repetition rate, as well as the required signal-to-noise for evolution of turbulent structures in the plasma, need to be considered in the context of spatial and temporal scales. These quantities were evaluated for several experimental conditions. The ion species was selected on the basis of maximizing signal-to-noise, matching to the laser's tuning range, and compatibility with the plasma. The design of the laser system incorporates several state-of-the-art features that in combination produce a laser system having very novel characteristics. The basic requirement of this project is for a repetitively pulsed, 5 Hz laser system that produces a burst of 378 nm UV laser pulses, each of ∼50 mJ energy and ∼100 ns pulsewidth, where the number and the separation of the individual pulses can be varied between 10-20, and 1-5 μsec, respectively. A further consideration was matching the CCD camera characteristics, such as the frame rate and number of frames, to the burst of laser pulses which requires a rather unique CCD camera. Such a camera has been developed by Princeton Scientific Instruments, Inc. (PSI). The camera has a unique frame storage capability on chip that can transfer a frame in one clock cycle and store, depending on the version, from 12-312 frames on the CCD chip before being read out. It also has sub-frame gating to capture and synchronize fast events such as a short laser pulse. The results of the Phase I

  9. Development of high repetition rate nitric oxide planar laser induced fluorescence imaging

    Science.gov (United States)

    Jiang, Naibo

    have obtained, for the first time by any known optical method, Planar Laser Induced Fluorescence (PLIF) image sequences at ultrahigh (≥100kHz) frame rates, in particular NO PLIF image sequences, have been obtained in a Mach 2 jet. We also studied the possibility of utilizing a 250 kHz pulsed Nd:YVO 4 laser as the master oscillator. 10-pulse-10-mus spacing burst sequences with reasonably uniform burst envelope have been obtained. The total energy of the burst sequence is ˜2.5J.

  10. Laser-induced radiation microbeam technology and simultaneous real-time fluorescence imaging in live cells.

    Science.gov (United States)

    Botchway, Stanley W; Reynolds, Pamela; Parker, Anthony W; O'Neill, Peter

    2012-01-01

    The use of nano- and microbeam techniques to induce and identify subcellular localized energy deposition within a region of a living cell provides a means to investigate the effects of low radiation doses. Particularly within the nucleus where the propagation and processing of deoxyribonucleic acid (DNA) damage (and repair) in both targeted and nontargeted cells, the latter being able to study cell-cell (bystander) effects. We have pioneered a near infrared (NIR) femtosecond laser microbeam to mimic ionizing radiation through multiphoton absorption within a 3D femtoliter volume of a highly focused Gaussian laser beam. The novel optical microbeam mimics both complex ionizing and UV-radiation-type cell damage including double strand breaks (DSBs). Using the microbeam technology, we have been able to investigate the formation of DNA DSB and subsequent recruitment of repair proteins to the submicrometer size site of damage introduced in viable cells. The use of a phosphorylated H2AX (γ-H2AX a marker for DSBs, visualized by immunofluorescent staining) and real-time imaging of fluorescently labeling proteins, the dynamics of recruitment of repair proteins in viable mammalian cells can be observed. Here we show the recruitment of ATM, p53 binding protein 1 (53BP1), and RAD51, an integral protein of the homologous recombination process in the DNA repair pathway and Ku-80-GFP involved in the nonhomologous end joining (NHEJ) pathway as exemplar repair process to show differences in the repair kinetics of DNA DSBs. The laser NIR multiphoton microbeam technology shows persistent DSBs at later times post laser irradiation which are indicative of DSBs arising at replication presumably from UV photoproducts or clustered damage containing single strand breaks (SSBs) that are also observed. Effects of the cell cycle may also be investigated in real time. Postirradiation and fixed cells studies show that in G1 cells a fraction of multiphoton laser-induced DSBs is persistent for >6h

  11. A new Technique for ultrafast velocity distribution measurements of atomic species by post-ionization laser induced fluorescence (PILIF)

    International Nuclear Information System (INIS)

    Tabares, F.L.

    1992-01-01

    A new method for single shot velocity distribution measurement of metallic impurities of relevance for studies involving continuous sources, such as limiter experiments in fusion devices or sputtering experiments, based in the combination of Resonant Enhanced Multiphoton Ionization (REMPI) and Laser Induced Fluorescence (LIF) is proposed. High ionization yield and good time resolution are expected according to the numerical simulation of the experiment that has been run for several atomic species. Other possible applications of REMPI to plasma edge physics and to conventional techniques for velocity distribution measurements are briefly addressed. (author)

  12. A new technique for ultrafast velocity distribution measurements of atomic species by post-ionization laser induced fluorescent (PILIF)

    International Nuclear Information System (INIS)

    Tabares, F.L.

    1992-01-01

    A new method for single shot velocity distribution measurement of metallic impurities of relevance for studies involving continuous sources, such as limiter experiments in fusion devices or sputtering experiments, based in the combination of Resonant Enhanced Multiphoton ionization (REMPI) and Laser Induced Fluorescence (LIF) is proposed. High ionization yield and good time resolution are expected according to the numerical simulation of the experiment that has been run for several atomic species. Other possible applications of REMPI to plasma edge physics and to conventional techniques for velocity distribution measurements are briefly addressed. (Author) 8 refs

  13. A new technique for ultrafast velocity distribution measurements of atomic species by post-ionization laser induced fluorescent (PILIF)

    Energy Technology Data Exchange (ETDEWEB)

    Tabares, F.L.

    1992-07-01

    A new method for single shot velocity distribution measurement of metallic impurities of relevance for studies involving continuous sources, such as limiter experiments in fusion devices or sputtering experiments, based in the combination of Resonant Enhanced Multiphoton ionization (REMPI) and Laser Induced Fluorescence (LIF) is proposed. High ionization yield and good time resolution are expected according to the numerical simulation of the experiment that has been run for several atomic species. Other possible applications of REMPI to plasma edge physics and to conventional techniques for velocity distribution measurements are briefly addressed. (Author) 8 refs.

  14. Experimental studies of the propagation of electrostatic ion perturbations by time-resolved laser-induced fluorescence

    International Nuclear Information System (INIS)

    Bachet, G.; Skiff, F.; Doveil, F.; Stern, R.A.

    2001-01-01

    Effects induced by the propagation of several kinds of electrostatic perturbation in a low-density collisionless argon plasma are observed with space, time, and velocity-resolved laser-induced fluorescence (LIF). The propagation of strong self-organized ion structures is observed and the associated electric field is determined. Snap shots of the ion phase space with a time resolution of 2 μs can be reconstructed from the experimental data. All the terms of the kinetic equation can also be determined from the data. A one-dimensional (1D) numerical simulation reproduces qualitatively the experimentally observed ion phase space behavior

  15. Mixture-fraction imaging at 1  kHz using femtosecond laser-induced fluorescence of krypton.

    Science.gov (United States)

    Richardson, Daniel R; Jiang, Naibo; Stauffer, Hans U; Kearney, Sean P; Roy, Sukesh; Gord, James R

    2017-09-01

    Femtosecond, two-photon-absorption laser-induced-fluorescence (TALIF) imaging measurements of krypton (Kr) are demonstrated to study mixing in gaseous flows. A measurement approach is presented in which observed Kr TALIF signals are 7 times stronger than the current state-of-the-art methodology. Fluorescence emission is compared for different gas pressures and excitation wavelengths, and the strongest fluorescence signals were observed when the excitation wavelength was tuned to 212.56 nm. Using this optimized excitation scheme, 1-kHz, single-laser-shot visualizations of unsteady flows and two-dimensional measurements of mixture fraction and scalar dissipation rate of a Kr-seeded jet are demonstrated.

  16. Unexpected temporal evolution of atomic spectral lines of aluminum in a laser induced breakdown spectroscopy experiment

    International Nuclear Information System (INIS)

    Saad, Rawad; L'Hermite, Daniel; Bousquet, Bruno

    2014-01-01

    The temporal evolution of the laser induced breakdown (LIBS) signal of a pure aluminum sample was studied under nitrogen and air atmospheres. In addition to the usual decrease of signal due to plasma cooling, unexpected temporal evolutions were observed for a spectral lines of aluminum, which revealed the existence of collisional energy transfer effects. Furthermore, molecular bands of AlN and AlO were observed in the LIBS spectra, indicating recombination of aluminum with the ambient gas. Within the experimental conditions reported in this study, both collisional energy transfer and recombination processes occurred around 1.5 μs after the laser shot. This highlights the possible influence of collisional and chemical effects inside the plasma that can play a role on LIBS signals. - Highlights: • Persistence of two Al I lines related to the 61,844 cm −1 energy level only under nitrogen atmosphere. • Collisional energy transfer effect exists between aluminum and nitrogen. • Observation of molecular band of AlN (under nitrogen) and AlO (under air) after a delay time of 1.5 µs. • 20% of oxygen in air is sufficient to annihilate both the collisional energy transfer effect and the AlN molecular formation

  17. Does ozone enhance the remineralizing potential of nanohydroxyapatite on artificially demineralized enamel? A laser induced fluorescence study

    Science.gov (United States)

    Srinivasan, Samuelraj; Prabhu, Vijendra; Chandra, Subhash; Koshy, Shalini; Acharya, Shashidhar; Mahato, Krishna K.

    2014-02-01

    The present era of minimal invasive dentistry emphasizes the early detection and remineralization of initial enamel caries. Ozone has been shown to reverse the initial demineralization before the integrity of the enamel surface is lost. Nano-hydroxyapatite is a proven remineralizing agent for early enamel caries. In the present study, the effect of ozone in enhancing the remineralizing potential of nano-hydroxyapatite on artificially demineralized enamel was investigated using laser induced fluorescence. Thirty five sound human premolars were collected from healthy subjects undergoing orthodontic treatment. Fluorescence was recorded by exciting the mesial surfaces using 325 nm He-Cd laser with 2 mW power. Tooth specimens were subjected to demineralization to create initial enamel caries. Following which the specimens were divided into three groups, i.e ozone (ozonated water for 2 min), without ozone and artificial saliva. Remineralization regimen was followed for 3 weeks. The fluorescence spectra of the specimens were recorded from all the three experimental groups at baseline, after demineralization and remineralization. The average spectrum for each experimental group was used for statistical analysis. Fluorescence intensities of Ozone treated specimens following remineralization were higher than that of artificial saliva, and this difference was found to be statistically significant (P<0.0001). In a nutshell, ozone enhanced the remineralizing potential of nanohydroxyapatite, and laser induced fluorescence was found to be effective in assessing the surface mineral changes in enamel. Ozone can be considered an effective agent in reversing the initial enamel caries there by preventing the tooth from entering into the repetitive restorative cycle.

  18. Distribution of Fe atom density in a dc magnetron sputtering plasma source measured by laser-induced fluorescence imaging spectroscopy

    Science.gov (United States)

    Shibagaki, K.; Nafarizal, N.; Sasaki, K.; Toyoda, H.; Iwata, S.; Kato, T.; Tsunashima, S.; Sugai, H.

    2003-10-01

    Magnetron sputtering discharge is widely used as an efficient method for thin film fabrication. In order to achieve the optimized fabrication, understanding of the kinetics in plasmas is essential. In the present work, we measured the density distribution of sputtered Fe atoms using laser-induced fluorescence imaging spectroscopy. A dc magnetron plasma source with a Fe target was used. An area of 20 × 2 mm in front of the target was irradiated by a tunable laser beam having a planar shape. The picture of laser-induced fluorescence on the laser beam was taken using an ICCD camera. In this way, we obtained the two-dimensional image of the Fe atom density. As a result, it has been found that the Fe atom density observed at a distance of several centimeters from the target is higher than that adjacent to the target, when the Ar gas pressure was relatively high. It is suggested from this result that some gas-phase production processes of Fe atoms are available in the plasma. This work has been performed under the 21st Century COE Program by the Ministry of Education, Culture, Sports, Science and Technology in Japan.

  19. Photodissociation dynamics of 2-chloro-6-nitrotoluene and nitrocyclopentane in gas phase: Laser-induced fluorescence detection of OH

    Energy Technology Data Exchange (ETDEWEB)

    Kawade, Monali N.; Saha, Ankur; Upadhyaya, Hari P.; Kumar, Awadhesh; Naik, Prakash D., E-mail: pdnaik@barc.gov.in

    2014-10-31

    Highlights: • Photodissociation studies on chloronitrotoluene (ClNT) and nitrocyclopentane (NCP). • Nascent OH product detected state selectively using laser induced fluorescence. • OH formation takes place from the ground electronic state with an exit barrier. • UV photodissociation dynamics of ClNT and NCP is different. - Abstract: Photodissociation of 2-chloro-6-nitrotoluene (ClNT) at 193, 248 and 266 nm and nitrocyclopentane (NCP) at 193 nm leads to the formation of OH, as detected by laser-induced fluorescence (LIF). The nascent OH produced from the photolysis of ClNT at all the wavelengths is vibrationally cold, with the Boltzmann type rotational state distributions. However, the nascent OH product from NCP is in the ground and vibrationally excited states with the measured average relative population in ν{sup ″}=1 to that in ν{sup ″}=0 of 0.12 ± 0.03, and these levels are characterized by rotational temperatures of 650 ± 180 K and 1570 ± 90 K, respectively. The translational energy partitioned in the OH fragment has been measured for photodissociation of both ClNT and NCP. On the basis of both the experimental results and the ground state molecular orbital (MO) calculations, a plausible mechanism for the OH formation has been proposed.

  20. Diode-Laser Induced Fluorescence Spectroscopy of an Optically Thick Plasma in Combination with Laser Absorption Spectroscopy

    Directory of Open Access Journals (Sweden)

    S. Nomura

    2013-01-01

    Full Text Available Distortion of laser-induced fluorescence profiles attributable to optical absorption and saturation broadening was corrected in combination with laser absorption spectroscopy in argon plasma flow. At high probe-laser intensity, saturated absorption profiles were measured to correct probe-laser absorption. At low laser intensity, nonsaturated absorption profiles were measured to correct fluorescence reabsorption. Saturation broadening at the measurement point was corrected using a ratio of saturated to non-saturated broadening. Observed LIF broadening and corresponding translational temperature without correction were, respectively, 2.20±0.05 GHz and 2510±100 K and corrected broadening and temperature were, respectively, 1.96±0.07 GHz and 1990±150 K. Although this correction is applicable only at the center of symmetry, the deduced temperature agreed well with that obtained by LAS with Abel inversion.

  1. Evaluation of self-absorption coefficients of aluminum emission lines in laser-induced breakdown spectroscopy measurements

    International Nuclear Information System (INIS)

    El Sherbini, A.M.; El Sherbini, Th.M.; Hegazy, H.; Cristoforetti, G.; Legnaioli, S.; Palleschi, V.; Pardini, L.; Salvetti, A.; Tognoni, E.

    2005-01-01

    In quantitative Laser Induced Breakdown Spectroscopy (LIBS) measurements it is essential to account for the effect of self-absorption on the emission lines intensity. In order to quantify this effect, in this paper we propose a simple method for evaluating the ratio between the actual measured line intensity and the intensity expected in absence of self-absorption and, if necessary, correcting the effect of self-absorption on line intensity. The method, based on a homogeneous plasma model, is applicable when the plasma electron density is known and in particular to lines whose Stark broadening parameter is available

  2. Characterization of type I, II, III, IV, and V collagens by time-resolved laser-induced fluorescence spectroscopy

    Science.gov (United States)

    Marcu, Laura; Cohen, David; Maarek, Jean-Michel I.; Grundfest, Warren S.

    2000-04-01

    The relative proportions of genetically distinct collagen types in connective tissues vary with tissue type and change during disease progression, development, wound healing, aging. This study aims to 1) characterize the spectro- temporal fluorescence emission of fiber different types of collagen and 2) assess the ability of time-resolved laser- induced fluorescence spectroscopy to distinguish between collagen types. Fluorescence emission of commercially available purified samples was induced with nitrogen laser excitation pulses and detected with a MCP-PMT connected to a digital storage oscilloscope. The recorded time-resolved emission spectra displayed distinct fluorescence emission characteristics for each collagen type. The time domain information complemented the spectral domain intensity data for improved discrimination between different collagen types. Our results reveal that analysis of the fluorescence emission can be used to characterize different species of collagen. Also, the results suggest that time-resolved spectroscopy can be used for monitoring of connective tissue matrix composition changes due to various pathological and non-pathological conditions.

  3. Laser-induced emission, fluorescence and Raman hybrid setup: A versatile instrument to analyze materials from cultural heritage

    Science.gov (United States)

    Syvilay, D.; Bai, X. S.; Wilkie-Chancellier, N.; Texier, A.; Martinez, L.; Serfaty, S.; Detalle, V.

    2018-02-01

    The aim of this research project was the development of a hybrid system in laboratory coupling together three analytical techniques, namely laser-induced breakdown spectroscopy (LIBS), laser-induced fluorescence (LIF) and Raman spectroscopy in a single instrument. The rationale for combining these three spectroscopies was to identify a material (molecular and elemental analysis) without any preliminary preparation, regardless of its organic or inorganic nature, on the surface and in depth, without any surrounding light interference thanks to time resolution. Such instrumentation would allow characterizing different materials from cultural heritage. A complete study on LIBS-LIF-Raman hybrid was carried out, from its conception to instrumental achievement, in order to elaborate a strategy of analysis according to the material and to be able to address conservation issues. From an instrumental point of view, condensing the three spectroscopies was achieved by using a single laser for excitation and two spectrometers (time-integrated and not time-integrated) for light collection. A parabolic mirror was used as collecting system, while three excitation sources directed through this optical system ensured the examination of a similar probe area. Two categories of materials were chosen to test the hybrid instrumentation on cultural heritage applications (copper corrosion products and wall paintings). Some examples are reported to illustrate the wealth of information provided by the hybrid, thus demonstrating its great potential to be used for cultural heritage issues. Finally, several considerations are outlined aimed at further improving the hybrid.

  4. Measurements of excited-state-to-excited-state transition probabilities and photoionization cross-sections using laser-induced fluorescence and photoionization signals

    International Nuclear Information System (INIS)

    Shah, M.L.; Sahoo, A.C.; Pulhani, A.K.; Gupta, G.P.; Dikshit, B.; Bhatia, M.S.; Suri, B.M.

    2014-01-01

    Laser-induced photoionization and fluorescence signals were simultaneously observed in atomic samarium using Nd:YAG-pumped dye lasers. Two-color, three-photon photoionization and two-color fluorescence signals were recorded simultaneously as a function of the second-step laser power for two photoionization pathways. The density matrix formalism has been employed to analyze these signals. Two-color laser-induced fluorescence signal depends on the laser powers used for the first and second-step transitions as well as the first and second-step transition probability whereas two-color, three-photon photoionization signal depends on the third-step transition cross-section at the second-step laser wavelength along with the laser powers and transition probability for the first and second-step transitions. Two-color laser-induced fluorescence was used to measure the second-step transition probability. The second-step transition probability obtained was used to infer the photoionization cross-section. Thus, the methodology combining two-color, three-photon photoionization and two-color fluorescence signals in a single experiment has been established for the first time to measure the second-step transition probability as well as the photoionization cross-section. - Highlights: • Laser-induced photoionization and fluorescence signals have been simultaneously observed. • The density matrix formalism has been employed to analyze these signals. • Two-color laser-induced fluorescence was used to measure the second-step transition probability. • The second-step transition probability obtained was used to infer the photoionization cross-section. • Transition probability and photoionization cross-section have been measured in a single experiment

  5. Amine Analysis Using AlexaFluor 488 Succinimidyl Ester and Capillary Electrophoresis with Laser-Induced Fluorescence

    Directory of Open Access Journals (Sweden)

    Christian G. Kendall

    2015-01-01

    Full Text Available Fluorescent probes enable detection of otherwise nonfluorescent species via highly sensitive laser-induced fluorescence. Organic amines are predominantly nonfluorescent and are of analytical interest in agricultural and food science, biomedical applications, and biowarfare detection. Alexa Fluor 488 N-hydroxysuccinimidyl ester (AF488 NHS-ester is an amine-specific fluorescent probe. Here, we demonstrate low limit of detection of long-chain (C9 to C18 primary amines and optimize AF488 derivatization of long-chain primary amines. The reaction was found to be equally efficient in all solvents studied (dimethylsulfoxide, ethanol, and N,N-dimethylformamide. While an organic base (N,N-diisopropylethylamine is required to achieve efficient reaction between AF488 NHS-ester and organic amines with longer hydrophobic chains, high concentrations (>5 mM result in increased levels of ethylamine and propylamine in the blank. Optimal incubation times were found to be >12 hrs at room temperature. We present an initial capillary electrophoresis separation for analysis using a simple micellar electrokinetic chromatography (MEKC buffer consisting of 12 mM sodium dodecylsulfate (SDS and 5 mM carbonate, pH 10. Limits of detection using the optimized labeling conditions and these separation conditions were 5–17 nM. The method presented here represents a novel addition to the arsenal of fluorescent probes available for highly sensitive analysis of small organic molecules.

  6. Using violet laser-induced chlorophyll fluorescence emission spectra for crop yield assessment of cowpea (Vigna unguiculata (L) Walp) varieties

    Science.gov (United States)

    Anderson, Benjamin; Buah-Bassuah, Paul K.; Tetteh, Jonathan P.

    2004-07-01

    The use of violet laser-induced chlorophyll fluorescence (LICF) emission spectra to monitor the growth of five varieties of cowpea in the University of Cape Coast Botanical Garden is presented. Radiation from a continuous-wave violet laser diode emitting at 396 nm through a fibre is closely incident on in vivo leaves of cowpea to excite chlorophyll fluorescence, which is detected by an integrated spectrometer with CCD readout. The chlorophyll fluorescence spectra with peaks at 683 and 731 nm were used for growth monitoring of the cowpea plants over three weeks and analysed using Gaussian spectral functions with curve fitted parameters to determine the peak positions, area under the spectral curve and the intensity ratio F683/F731. The variation in the intensity ratio of the chlorophyll bands showed sensitive changes indicating the photosynthetic activity of the cowpea varieties. A discussion of the fluorescence result as compared to conventional assessment is presented with regard to discrimination between the cowpea varieties in terms of crop yield performance.

  7. Influence of ethanol admixture on the determination of equivalence ratios in DISI engines by laser-induced fluorescence.

    Science.gov (United States)

    Storch, Michael; Lind, Susanne; Will, Stefan; Zigan, Lars

    2016-10-20

    In this work, the planar laser-induced fluorescence of a fuel tracer is applied for the analysis of mixture formation for various ethanol/iso-octane blends in a direct-injection spark-ignition (DISI) engine. The tracer triethylamine (TEA) was added to pure iso-octane and ethanol as well as to their blends E20 and E85 for the measurement of the fuel/air ratio. In general, ethanol blending strongly affects the mixture formation process, which is caused by specific physical fuel properties influencing the evaporation process of ethanol in comparison to iso-octane. As interactions of the fuel and tracer fluorescence appear possible, TEA fluorescence was studied for different fuel blends in a cuvette, in a calibration cell under constant conditions, and in an optically accessible internal combustion engine at late injection timing. It was found that ethanol blending strongly affects the fluorescence intensity of TEA in the liquid phase, which can be explained by the interaction of the tracer and ethanol molecules. However, in the gas phase a quantification of the fuel/air ratio is possible for different ethanol fuel blends, which is demonstrated in a DISI engine. Under stratified charge conditions the engine results showed a significant impact of a high amount of ethanol on the mixture formation process, leading to a leaner mixture in comparison to iso-octane.

  8. Measurements with magnetic field in the National Spherical Torus Experiment using the motional Stark effect with laser induced fluorescence diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Foley, E. L.; Levinton, F. M. [Nova Photonics, Inc., Princeton, New Jersey 08540 (United States)

    2013-04-15

    The motional Stark effect with laser-induced fluorescence diagnostic (MSE-LIF) has been installed and tested on the National Spherical Torus Experiment (NSTX) at the Princeton Plasma Physics Lab. The MSE-LIF diagnostic will be capable of measuring radially resolved profiles of magnetic field magnitude or pitch angle in NSTX plasmas. The system includes a diagnostic neutral hydrogen beam and a laser which excites the n = 2 to n = 3 transition. A viewing system has been implemented which will support up to 38 channels from the plasma edge to past the magnetic axis. First measurements of MSE-LIF signals in the presence of small applied magnetic fields in neutral gas are reported.

  9. Measurements with magnetic field in the National Spherical Torus Experiment using the motional Stark effect with laser induced fluorescence diagnostic

    Science.gov (United States)

    Foley, E. L.; Levinton, F. M.

    2013-04-01

    The motional Stark effect with laser-induced fluorescence diagnostic (MSE-LIF) has been installed and tested on the National Spherical Torus Experiment (NSTX) at the Princeton Plasma Physics Lab. The MSE-LIF diagnostic will be capable of measuring radially resolved profiles of magnetic field magnitude or pitch angle in NSTX plasmas. The system includes a diagnostic neutral hydrogen beam and a laser which excites the n = 2 to n = 3 transition. A viewing system has been implemented which will support up to 38 channels from the plasma edge to past the magnetic axis. First measurements of MSE-LIF signals in the presence of small applied magnetic fields in neutral gas are reported.

  10. Setting-up of the Laser Induced Fluorescence diagnostic. Measurements of Cr density in a neon glow discharge

    International Nuclear Information System (INIS)

    Tafalla, D.; Cal, E. de la; Tabares, F. L.

    1994-01-01

    A plasma diagnostic based on the Laser Induced Fluorescence (LIF) technique has been set up in the Fusion Division at the CIEMAT. In a preliminary experiment, the density of sputtered chromium atoms produced in a neon glow discharge was measured. Firstly, the laser beam was characterized by calibration of its wavelength, bandwidth and energy profile and Rayleigh scattering in N2 was used for the optical system calibration. An absolute density of Cr atoms of n ∼ 5x10 cm was obtained in discharges at 100 mA and pressure of 15 mTorr and a linear dependence of the LIF signal us. current was found. These values are in agreement with those expected from the tabulated sputtering yields and the thermalization and diffusion of the sputtered atoms into the Ne plasma. (Author) 19 refs

  11. Setting-up of the Laser Induced Fluorescence diagnostic. Measurements of Cr density in a neon glow discharge

    International Nuclear Information System (INIS)

    Tafalla, D.; Cal, E. de la; Tabares, F.L.

    1994-01-01

    A plasma diagnostic based on the Laser Induced Fluorescence (LIF) technique has been set up in the Fusion Division at the CIEMAT. In a preliminary experiment, The density of sputtered chromium atoms produced in a neon glow discharge was measured. Firstly, the laser beam was characterized by calibration of its wavelength bandwidth and energy profile and Rayleigh scattering in N 2 was used for the optical system calibration. An absolute density of Cr atoms of n= 5x10''9 cm''-3 was obtained in discharges at 100 mA and pressure of 15 mTorr and a linear dependence of the LIF signal US. current was found. These values are in agreement with those expected from the tabulated sputtering yields and the thermalization and diffusion of the sputtered atoms into the Ne plasma

  12. MHz-rate nitric oxide planar laser-induced fluorescence imaging in a Mach 10 hypersonic wind tunnel.

    Science.gov (United States)

    Jiang, Naibo; Webster, Matthew; Lempert, Walter R; Miller, Joseph D; Meyer, Terrence R; Ivey, Christopher B; Danehy, Paul M

    2011-02-01

    Nitric oxide planar laser-induced fluorescence (NO PLIF) imaging at repetition rates as high as 1 MHz is demonstrated in the NASA Langley 31 in. Mach 10 hypersonic wind tunnel. Approximately 200 time-correlated image sequences of between 10 and 20 individual frames were obtained over eight days of wind tunnel testing spanning two entries in March and September of 2009. The image sequences presented were obtained from the boundary layer of a 20° flat plate model, in which transition was induced using a variety of different shaped protuberances, including a cylinder and a triangle. The high-speed image sequences captured a variety of laminar and transitional flow phenomena, ranging from mostly laminar flow, typically at a lower Reynolds number and/or in the near wall region of the model, to highly transitional flow in which the temporal evolution and progression of characteristic streak instabilities and/or corkscrew-shaped vortices could be clearly identified.

  13. A laser-induced-fluorescence visualization study of transverse, sonic fuel injection in a nonreacting supersonic combustor

    Science.gov (United States)

    Mcdaniel, J. C.; Graves, J., Jr.

    1986-01-01

    The present paper reports work which has been conducted in the first phase of a research program which is to provide a data base of spatially-resolved measurements in nonreacting supersonic combustors. In the measurements, a nonintrusive diagnostic technique based on the utilization of laser-induced fluorescence (LIF) is employed. The reported work had the objective to conduct LIF visualization studies of the injection of a simulated fuel into a Mach 2.07 airstream for comparison with corresponding numerical calculations. Attention is given to injection from a single orifice into a constant-area duct, injection from a single orifice behind a rearward-facing step, and injection from staged orifices behind a rearward-facing step.

  14. Chiral separation of amino acids in biological fluids by micellar electrokinetic chromatography with laser-induced fluorescence detection.

    Science.gov (United States)

    Thorsén, G; Bergquist, J

    2000-08-18

    A method is presented for the chiral analysis of amino acids in biological fluids using micellar electrokinetic chromatography (MEKC) and laser-induced fluorescence (LIF). The amino acids are derivatized with the chiral reagent (+/-)-1-(9-anthryl)-2-propyl chloroformate (APOC) and separated using a mixed micellar separation system. No tedious pre-purification of samples is required. The excellent separation efficiency and good detection capabilities of the MEKC-LIF system are exemplified in the analysis of urine and cerebrospinal fluid. This is the first time MEKC has been reported for chiral analysis of amino acids in biological fluids. The amino acids D-alanine, D-glutamine, and D-aspartic acid have been observed in cerebrospinal fluid, and D-alanine and D-glutamic acid in urine. To the best of our knowledge no measurements of either D-alanine in cerebrospinal fluid or D-glutamic acid in urine have been presented in the literature before.

  15. Classification of Laser Induced Fluorescence Spectra from Normal and Malignant bladder tissues using Learning Vector Quantization Neural Network in Bladder Cancer Diagnosis

    DEFF Research Database (Denmark)

    Karemore, Gopal Raghunath; Mascarenhas, Kim Komal; Patil, Choudhary

    2008-01-01

    In the present work we discuss the potential of recently developed classification algorithm, Learning Vector Quantization (LVQ), for the analysis of Laser Induced Fluorescence (LIF) Spectra, recorded from normal and malignant bladder tissue samples. The algorithm is prototype based and inherently...

  16. New Method Based on Capillary Electrophoresis with Laser-Induced Fluorescence Detection (CE-LIF) to Monitor Interaction between Nanoparticles and the Amyloid-β Peptide

    NARCIS (Netherlands)

    Brambilla, Davide; Verpillot, Romain; Taverna, Myriam; de Kimpe, Line; Le Droumaguet, Benjamin; Nicolas, Julien; Canovi, Mara; Gobbi, Marco; Mantegazza, Francesco; Salmona, Mario; Nicolas, Valérie; Scheper, Wiep; Couvreur, Patrick; Andrieux, Karine

    2010-01-01

    A novel application of capillary electrophoresis with laser-induced fluorescence detection (CE-LIF) was proposed to efficiently detect and monitor the interaction between polymeric nanoparticles and the β-Amyloid peptide (Aβ(1-42)), a biomarker for Alzheimer's Disease (AD), at concentrations close

  17. Laser induced fluorescence and phosphorescence of matrix isolated glyoxal: Evidence for exciplex formation in the  1Au and  3Au states

    NARCIS (Netherlands)

    IJzendoorn, van L.J.; Allamandola, L.J.; Baas, F.; Koernig, S.; Greenberg, J.M.

    1986-01-01

    Laser-induced fluorescence (¿1Au¿¿1Ag) and phosphorescence (¿3Au¿¿1Ag) as well as absorption and excitation spectra of glyoxal in Ar, N2, and CO matrices have been measured at 12 K. Supplementary infrared absorption spectra have also been taken. Although the dominant band in the absorption and

  18. Simultaneous Laser-induced Fluorescence of Nitric Oxide and Atomic Oxygen in the Hypersonic Materials Environment Test System Arcjet Facility

    Science.gov (United States)

    Johansen, Craig; Lincoln, Daniel; Bathel, Brett; Inman, Jennifer; Danehy, Paul

    2014-01-01

    Simultaneous nitric oxide (NO) and atomic oxygen (O) laser induced fluorescence (LIF) experiments were performed in the Hypersonic Materials Environmental Test System (HYMETS) facility at the NASA Langley Research Center. The data serves as an experimental database for validation for chemical and thermal nonequilibrium models used in hypersonic flows. Measurements were taken over a wide range of stagnation enthalpies (6.7 - 18.5 MJ/kg) using an Earth atmosphere simulant with a composition of 75% N2, 20% O2, and 5% Ar (by volume). These are the first simultaneous measurements of NO and O LIF to be reported in literature for the HYMETS facility. The maximum O LIF mean signal intensity was observed at a stagnation enthalpy of approximately 12 MJ/kg while the maximum NO LIF mean signal intensity was observed at a stagnation enthalpy of 6.7 MJ/kg. Experimental results were compared to simple fluorescence model that assumes equilibrium conditions in the plenum and frozen chemistry in the isentropic nozzle expansion (Mach 5). The equilibrium calculations were performed using CANTERA v2.1.1 with 16 species. The fluorescence model captured the correlation in mean O and NO LIF signal intensities over the entire range of stagnation enthalpies tested. Very weak correlations between single-shot O and NO LIF intensities were observed in the experiments at all of the stagnation enthalpy conditions.

  19. Applicability of UV laser-induced solid-state fluorescence spectroscopy for characterization of solid dosage forms.

    Science.gov (United States)

    Woltmann, Eva; Meyer, Hans; Weigel, Diana; Pritzke, Heinz; Posch, Tjorben N; Kler, Pablo A; Schürmann, Klaus; Roscher, Jörg; Huhn, Carolin

    2014-10-01

    High production output of solid pharmaceutical formulations requires fast methods to ensure their quality. Likewise, fast analytical procedures are required in forensic sciences, for example at customs, to substantiate an initial suspicion. We here present the design and the optimization of an instrumental setup for rapid and non-invasive characterization of tablets by laser-induced fluorescence spectroscopy (with a UV-laser (λ ex = 266 nm) as excitation source) in reflection geometry. The setup was first validated with regard to repeatability, bleaching phenomena, and sensitivity. The effect on the spectra by the physical and chemical properties of the samples, e.g. their hardness, homogeneity, chemical composition, and granule grain size of the uncompressed material, using a series of tablets, manufactured in accordance with design of experiments, was investigated. Investigation of tablets with regard to homogeneity, especially, is extremely important in pharmaceutical production processes. We demonstrate that multiplicative scatter correction is an appropriate tool for data preprocessing of fluorescence spectra. Tablets with different physical and chemical characteristics can be discriminated well from their fluorescence spectra by subjecting the results to principal component analysis.

  20. Pressure and temperature dependence of laser-induced fluorescence of Sm:YAG to 100 kbar and 700 degree C and an empirical model

    International Nuclear Information System (INIS)

    Hess, N.J.; Schiferl, D.

    1990-01-01

    The inability to measure pressure with accuracy at high temperature has been a hindrance to the development of simultaneous high-temperature, high-pressure experimental techniques. The results of recent laser-induced fluorescence studies at high temperature and high pressure indicate that Sm:YAG is a promising pressure calibrant with very low-temperature sensitivity. The most intense feature in the fluorescence spectrum is a doublet at 16186.5 cm -1 . The Sm:YAG doublet exhibits a pressure-induced peak shift comparable to the R 1 shift of ruby. However, the temperature-induced shift of the doublet is almost two orders of magnitude less than that observed for the R 1 peak. Simultaneous high-pressure-temperature experiments indicate that the pressure and temperature effects on the frequency and line shape can be added linearly. An empirical model based on the linear combination of pressure dependent frequency shift and temperature dependent linewidth and intensity ratio successfully predicts the doublet line shape at simultaneous pressure and temperature. Use of the model facilitates measurement of peak position at high temperature resulting in improved accuracy and repeatability of the pressure determination. Pressure measurements at 400 degree C and 40 kbar based on the Sm:YAG doublet peak position agree with the temperature-corrected ruby R 1 pressure measurement to within 3 kbar. At 15 kbar and 900 degree C the uncertainty in the Sm:YAG fluorescence peak wavelength is 5 cm -1 due to temperature-induced line broadening; this corresponds to an uncertainty in the pressure determination of ±2.5 kbar. The high thermal and chemical stability of YAG materials make Sm:YAG an ideal pressure calibrant for high-temperature applications

  1. Studies of the laser-induced fluorescence of explosives and explosive compositions.

    Energy Technology Data Exchange (ETDEWEB)

    Hargis, Philip Joseph, Jr. (,; .); Thorne, Lawrence R.; Phifer, Carol Celeste; Parmeter, John Ethan; Schmitt, Randal L.

    2006-10-01

    Continuing use of explosives by terrorists throughout the world has led to great interest in explosives detection technology, especially in technologies that have potential for standoff detection. This LDRD was undertaken in order to investigate the possible detection of explosive particulates at safe standoff distances in an attempt to identify vehicles that might contain large vehicle bombs (LVBs). The explosives investigated have included the common homogeneous or molecular explosives, 2,4,6-trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), cyclonite or hexogen (RDX), octogen (HMX), and the heterogeneous explosive, ammonium nitrate/fuel oil (ANFO), and its components. We have investigated standard excited/dispersed fluorescence, laser-excited prompt and delayed dispersed fluorescence using excitation wavelengths of 266 and 355 nm, the effects of polarization of the laser excitation light, and fluorescence imaging microscopy using 365- and 470-nm excitation. The four nitro-based, homogeneous explosives (TNT, PETN, RDX, and HMX) exhibit virtually no native fluorescence, but do exhibit quenching effects of varying magnitude when adsorbed on fluorescing surfaces. Ammonium nitrate and fuel oil mixtures fluoresce primarily due to the fuel oil, and, in some cases, due to the presence of hydrophobic coatings on ammonium nitrate prill or impurities in the ammonium nitrate itself. Pure ammonium nitrate shows no detectable fluorescence. These results are of scientific interest, but they provide little hope for the use of UV-excited fluorescence as a technique to perform safe standoff detection of adsorbed explosive particulates under real-world conditions with a useful degree of reliability.

  2. Laser-induced fluorescence measurements of argon ion velocities near the sheath boundary of an argon-xenon plasma

    International Nuclear Information System (INIS)

    Lee, Dongsoo; Severn, Greg; Oksuz, Lutfi; Hershkowitz, Noah

    2006-01-01

    The Bohm sheath criterion in single- and two-ion species plasma is studied with laser-induced fluorescence using a diode laser. Xenon is added to a low pressure unmagnetized dc hot filament argon discharge confined by surface multidipole magnetic fields. The Ar II transition at 668.614 nm is adopted for optical pumping to detect the fluorescence from the plasma and to measure the argon ion velocity distribution functions with respect to positions relative to a negatively biased boundary plate. The structures of the plasma sheath and presheath are measured by an emissive probe. The ion concentrations of the two-species in the bulk plasma are calculated from ion acoustic wave experiments. Results are compared with previous experiments of Ar-He plasmas in which the argon ions were the heavier ion species. Unlike the previous results, the argon speed is slower than its own Bohm velocity near the sheath-presheath boundary in the Ar-Xe plasma where argon ions are the lighter ion species. We argue that this result is consistent with the behaviour of the helium ion required by the generalized Bohm criterion in the previous experiments with Ar-He plasmas. Further, our results suggest that the measured argon ion speed approaches the ion sound speed of the system

  3. Dissociation energies of six NO2 isotopologues by laser induced fluorescence spectroscopy and zero point energy of some triatomic molecules.

    Science.gov (United States)

    Michalski, G; Jost, R; Sugny, D; Joyeux, M; Thiemens, M

    2004-10-15

    We have measured the rotationless photodissociation threshold of six isotopologues of NO2 containing 14N, 15N, 16O, and 18O isotopes using laser induced fluorescence detection and jet cooled NO2 (to avoid rotational congestion). For each isotopologue, the spectrum is very dense below the dissociation energy while fluorescence disappears abruptly above it. The six dissociation energies ranged from 25 128.56 cm(-1) for 14N16O2 to 25 171.80 cm(-1) for 15N18O2. The zero point energy for the NO2 isotopologues was determined from experimental vibrational energies, application of the Dunham expansion, and from canonical perturbation theory using several potential energy surfaces. Using the experimentally determined dissociation energies and the calculated zero point energies of the parent NO2 isotopologue and of the NO product(s) we determined that there is a common De = 26 051.17+/-0.70 cm(-1) using the Born-Oppenheimer approximation. The canonical perturbation theory was then used to calculate the zero point energy of all stable isotopologues of SO2, CO2, and O3, which are compared with previous determinations.

  4. Femtosecond, two-photon laser-induced-fluorescence imaging of atomic oxygen in an atmospheric-pressure plasma jet

    Science.gov (United States)

    Schmidt, Jacob B.; Sands, Brian L.; Kulatilaka, Waruna D.; Roy, Sukesh; Scofield, James; Gord, James R.

    2015-06-01

    Femtosecond, two-photon-absorption laser-induced-fluorescence (fs-TALIF) spectroscopy is employed to measure space- and time-resolved atomic-oxygen distributions in a nanosecond, repetitively pulsed, externally grounded, atmospheric-pressure plasma jet flowing helium with a variable oxygen admixture. The high-peak-intensity, low-average-energy femtosecond pulses result in increased TALIF signal with reduced photolytic inferences. This allows 2D imaging of absolute atomic-oxygen number densities ranging from 5.8   ×   1015 to 2.0   ×   1012cm-3 using a cooled CCD with an external intensifier. Xenon is used for signal and imaging-system calibrations to quantify the atomic-oxygen fluorescence signal. Initial results highlight a transition in discharge morphology from annular to filamentary, corresponding with a change in plasma chemistry from ozone to atomic oxygen production, as the concentration of oxygen in the feed gas is changed at a fixed voltage-pulse-repetition rate. In this configuration, significant concentrations of reactive oxygen species may be remotely generated by sustaining an active discharge beyond the confines of the dielectric capillary, which may benefit applications that require large concentrations of reactive oxygen species such as material processing or biomedical devices.

  5. Reaction-time-resolved measurements of laser-induced fluorescence in a shock tube with a single laser pulse

    Science.gov (United States)

    Zabeti, S.; Fikri, M.; Schulz, C.

    2017-11-01

    Shock tubes allow for the study of ultra-fast gas-phase reactions on the microsecond time scale. Because the repetition rate of the experiments is low, it is crucial to gain as much information as possible from each individual measurement. While reaction-time-resolved species concentration and temperature measurements with fast absorption methods are established, conventional laser-induced fluorescence (LIF) measurements with pulsed lasers provide data only at a single reaction time. Therefore, fluorescence methods have rarely been used in shock-tube diagnostics. In this paper, a novel experimental concept is presented that allows reaction-time-resolved LIF measurements with one single laser pulse using a test section that is equipped with several optical ports. After the passage of the shock wave, the reactive mixture is excited along the center of the tube with a 266-nm laser beam directed through a window in the end wall of the shock tube. The emitted LIF signal is collected through elongated sidewall windows and focused onto the entrance slit of an imaging spectrometer coupled to an intensified CCD camera. The one-dimensional spatial resolution of the measurement translates into a reaction-time-resolved measurement while the species information can be gained from the spectral axis of the detected two-dimensional image. Anisole pyrolysis was selected as the benchmark reaction to demonstrate the new apparatus.

  6. All Fiber-Coupled OH Planar Laser-Induced-Fluorescence (OH-PLIF)-Based Two-Dimensional Thermometry.

    Science.gov (United States)

    Hsu, Paul S; Jiang, Naibo; Patnaik, Anil K; Katta, Vish; Roy, Sukesh; Gord, James R

    2018-04-01

    Two-color, planar laser-induced fluorescence (PLIF)-based two-dimensional (2D) thermometry techniques for reacting flows, which are typically developed in the laboratory conditions, face a stiff challenge in their practical implementation in harsh environments such as combustion rigs. In addition to limited optical access, the critical experimental conditions (i.e., uncontrolled humidity, vibration, and large thermal gradients) often restrict sensitive laser system operation and cause difficulties maintaining beam-overlap. Thus, an all fiber-coupled, two-color OH-PLIF system has been developed, employing two long optical fibers allowing isolation of the laser and signal-collection systems. Two OH-excitation laser beams (∼283 nm and ∼286 nm) are delivered through a common 6 m long, 400 µm core, deep ultraviolet (UV)-enhanced multimode fiber. The fluorescence signal (∼310 nm) is collected by a 3 m long, UV-grade imaging fiber. Proof-of-principle temperature measurements are demonstrated in atmospheric pressure, near adiabatic, CH 4 /O 2 /N 2 jet flames. The effects of the excitation pulse interval on fiber transmission are investigated. The proof-of-principle measurements show significant promise for thermometry in harsh environments such as gas turbine engine tests.

  7. Spatially resolved analyses of uranium species using a coupled system made up of confocal laser-scanning microscopy (CLSM) and laser induced fluorescence spectroscopy (LIFS)

    International Nuclear Information System (INIS)

    Brockmann, S.; Grossmann, K.; Arnold, T.

    2014-01-01

    The fluorescent properties of uranium when excited by UV light are used increasingly for spectroscope analyses of uranium species within watery samples. Here, alongside the fluorescent properties of the hexavalent oxidation phases, the tetra and pentavalent oxidation phases also play an increasingly important role. The detection of fluorescent emission spectrums on solid and biological samples using (time-resolved) laser induced fluorescence spectroscopy (TRLFS or LIFS respectively) has, however, the disadvantage that no statements regarding the spatial localisation of the uranium can be made. However, particularly in complex, biological samples, such statements on the localisation of the uranium enrichment in the sample are desired, in order to e.g. be able to distinguish between intra and extra-cellular uranium bonds. The fluorescent properties of uranium (VI) compounds and minerals can also be used to detect their localisation within complex samples. So the application of fluorescent microscopic methods represents one possibility to localise and visualise uranium precipitates and enrichments in biological samples, such as biofilms or cells. The confocal laser-scanning microscopy (CLSM) is especially well suited to this purpose. Coupling confocal laser-scanning microscopy (CLSM) with laser induced fluorescence spectroscopy (LIFS) makes it possible to localise and visualise fluorescent signals spatially and three-dimensionally, while at the same time being able to detect spatially resolved, fluorescent-spectroscopic data. This technology is characterised by relatively low detection limits from up to 1.10 -6 M for uranium (VI) compounds within the confocal volume. (orig.)

  8. Signal enhancement of neutral He emission lines by fast electron bombardment of laser-induced He plasma

    Directory of Open Access Journals (Sweden)

    Hery Suyanto

    2016-08-01

    Full Text Available A time-resolved spectroscopic study is performed on the enhancement signals of He gas plasma emission using nanosecond (ns and picosecond (ps lasers in an orthogonal configuration. The ns laser is used for the He gas plasma generation and the ps laser is employed for the ejection of fast electrons from a metal target, which serves to excite subsequently the He atoms in the plasma. The study is focused on the most dominant He I 587.6 nm and He I 667.8 nm emission lines suggested to be responsible for the He-assisted excitation (HAE mechanism. The time-dependent intensity enhancements induced by the fast electrons generated with a series of delayed ps laser ablations are deduced from the intensity time profiles of both He emission lines. The results clearly lead to the conclusion that the metastable excited triplet He atoms are actually the species overwhelmingly produced during the recombination process in the ns laser-induced He gas plasma. These metastable He atoms are believed to serve as the major energy source for the delayed excitation of analyte atoms in ns laser-induced breakdown spectroscopy (LIBS using He ambient gas.

  9. Signal enhancement of neutral He emission lines by fast electron bombardment of laser-induced He plasma

    Energy Technology Data Exchange (ETDEWEB)

    Suyanto, Hery [Department of Physics, Faculty of Mathematics and Natural Sciences, Udayana University, Kampus Bukit Jimbaran, Denpasar 80361, Bali (Indonesia); Pardede, Marincan [Department of Electrical Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Hedwig, Rinda [Department of Computer Engineering, Bina Nusantara University, 9 K.H. Syahdan, Jakarta 14810 (Indonesia); Marpaung, Alion Mangasi [Department of Physics, Faculty of Mathematics and Natural Sciences, Jakarta State University, Rawamangun, Jakarta 12440 (Indonesia); Ramli, Muliadi [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Lie, Tjung Jie; Kurniawan, Koo Hendrik, E-mail: kurnia18@cbn.net.id [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Abdulmadjid, Syahrun Nur [Department of Physics, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Tjia, May On [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Physics of Magnetism and Photonics Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha,Bandung 40132 (Indonesia); Kagawa, Kiichiro [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Fukui Science Education Academy, Takagi Chuo 2 chome, Fukui 910-0804 (Japan)

    2016-08-15

    A time-resolved spectroscopic study is performed on the enhancement signals of He gas plasma emission using nanosecond (ns) and picosecond (ps) lasers in an orthogonal configuration. The ns laser is used for the He gas plasma generation and the ps laser is employed for the ejection of fast electrons from a metal target, which serves to excite subsequently the He atoms in the plasma. The study is focused on the most dominant He I 587.6 nm and He I 667.8 nm emission lines suggested to be responsible for the He-assisted excitation (HAE) mechanism. The time-dependent intensity enhancements induced by the fast electrons generated with a series of delayed ps laser ablations are deduced from the intensity time profiles of both He emission lines. The results clearly lead to the conclusion that the metastable excited triplet He atoms are actually the species overwhelmingly produced during the recombination process in the ns laser-induced He gas plasma. These metastable He atoms are believed to serve as the major energy source for the delayed excitation of analyte atoms in ns laser-induced breakdown spectroscopy (LIBS) using He ambient gas.

  10. Characterisation of an inlet pre-injector laser-induced fluorescence instrument for the measurement of atmospheric hydroxyl radicals

    Science.gov (United States)

    Novelli, A.; Hens, K.; Tatum Ernest, C.; Kubistin, D.; Regelin, E.; Elste, T.; Plass-Dülmer, C.; Martinez, M.; Lelieveld, J.; Harder, H.

    2014-10-01

    Atmospheric measurements of hydroxyl radicals (OH) are challenging due to a high reactivity and consequently low concentration. The importance of OH as an atmospheric oxidant has motivated a sustained effort leading to the development of a number of highly sensitive analytical techniques. Recent work has indicated that the laser-induced fluorescence of the OH molecules method based on the fluorescence assay by gas expansion technique (LIF-FAGE) for the measurement of atmospheric OH in some environments may be influenced by artificial OH generated within the instrument, and a chemical method to remove this interference was implemented in a LIF-FAGE system by Mao et al. (2012). While it is not clear whether other LIF-FAGE instruments suffer from the same interference, we have applied this method to our LIF-FAGE HORUS (Hydroxyl Radical Measurement Unit based on fluorescence Spectroscopy) system, and developed and deployed an inlet pre-injector (IPI) to determine the chemical zero level in the instrument via scavenging the ambient OH radical. We describe and characterise this technique in addition to its application at field sites in forested locations in Finland, Spain and Germany. Ambient measurements show that OH generated within the HORUS instrument is a non-negligible fraction of the total OH signal, which can comprise 30 to 80% during daytime and 60 to 100% during the night. The contribution of the background OH varied greatly between measurement sites and was likely related to the type and concentration of volatile organic compounds (VOCs) present at each particular location. Two inter-comparisons in contrasting environments between the HORUS instrument and two different chemical ionisation mass spectrometers (CIMS) are described to demonstrate the efficacy of IPI and the necessity of the chemical zeroing method for our LIF-FAGE instrument in such environments.

  11. Characterisation of an inlet pre-injector laser induced fluorescence instrument for the measurement of ambient hydroxyl radicals

    Science.gov (United States)

    Novelli, A.; Hens, K.; Tatum Ernest, C.; Kubistin, D.; Regelin, E.; Elste, T.; Plass-Dülmer, C.; Martinez, M.; Lelieveld, J.; Harder, H.

    2014-01-01

    Ambient measurements of hydroxyl radicals (OH) are challenging due to a high reactivity and consequently low concentration. The importance of OH as an atmospheric oxidant has resulted in a sustained effort leading to the development of a number of analytical techniques. Recent work has indicated that the laser-induced fluorescence of the OH molecules method based on the fluorescence assay by gas expansion technique (LIF-FAGE) for the measurement of atmospheric OH in some environments may be influenced by artificial OH generated within the instrument, and a chemical method to remove this interference was implemented in a LIF-FAGE system by Mao et al. (2012). We have applied this method to our LIF-FAGE HORUS (HydrOxyl Radical Measurement Unit based on fluorescence Spectroscopy) system, and developed and deployed an inlet pre-injector (IPI) to determine the chemical zero level in the instrument via scavenging the ambient OH radical. We describe and characterise this technique in addition to its application at field sites in forested locations in Finland, Spain, and Germany. Ambient measurements show that OH generated within the HORUS instrument is a non-negligible fraction of the total OH signal, which can comprise 30% to 80% during the day and 60% to 100% during the night. The contribution of the background OH varied greatly between measurement sites and was likely related to the type and concentration of volatile organic compounds (VOCs) present at each particular location. Two inter-comparisons in contrasting environments between the HORUS instrument and two different chemical ionisation mass spectrometers (CIMS) are described to demonstrate the efficacy of the inlet-pre-injector and the necessity of the chemical zeroing method in such environments.

  12. Technique for Increasing the Selectivity of the Method of Laser Fragmentation/Laser-Induced Fluorescence

    Science.gov (United States)

    Bobrovnikov, S. M.; Gorlov, E. V.; Zharkov, V. I.

    2018-05-01

    A technique for increasing the selectivity of the method of detecting high-energy materials (HEMs) based on laser fragmentation of HEM molecules with subsequent laser excitation of fluorescence of the characteristic NO fragments from the first vibrational level of the ground state is suggested.

  13. Planar laser-induced fluorescence fuel imaging during gas-turbine relight

    DEFF Research Database (Denmark)

    Read, Robert; Rogerson, J.W.; Hochgreb, S.

    2013-01-01

    of ignition when the airflow rate is high. In the presence of flame, medium-sized burning droplets are observed close to the injector centerline. Flame interference resulting from fluorescence of polycyclic aromatic hydrocarbons is apparent, but small, suggesting that kerosene planar laser...

  14. Kerosene detection using laser induced fluorescence imaging for aeronautical engines application; Detection du kerozene par imagerie de fluorescence induite par laser, pour application sur foyer aeronautique

    Energy Technology Data Exchange (ETDEWEB)

    Baranger, Ph.

    2004-10-15

    The new concepts of aeronautical engines, developed to follow the evolution of the European standards of pollution, are generally based on an improvement of the processes of liquid fuel injection and mixture in the combustion chamber. There is currently no model mature enough to work without experimental validation. The purpose of this thesis is to assess the possibility of measuring the kerosene (Jet A1) vapour distribution by PLIF (Planar Laser Induced Fluorescence). That measurement technique must quantitatively image the instantaneous concentrations fields of the vaporized fuel in a spray. The implementation of such a technique needs an experimental spectroscopic study, which was realized on the vapour of fuel. First of all, this study allowed us to determine the properties of the kerosene fluorescence spectrum versus physical parameters such as temperature, pressure or gas mixture composition, especially in presence of oxygen molecules. Then, it was shown that the fluorescence spectrum of the fuel could be reproduce in all physical conditions by a single mixture of four aromatics. Their photophysical properties were also analyzed. Following this spectroscopic study, a phenomenological model for the fluorescence of the gaseous fuel was set up. This model led us to a protocol for an optical diagnostic on this fuel vapour. An experiment was set up to test the implementation and the limits of this technique in simple laboratory conditions. This experiment confirmed that this is indeed a promising technique for the diagnostic of the fuel vapour in aeronautical engine. (author)

  15. Sensitive detection and separation of fluorescent derivatives using capillary electrophoresis with laser-induced fluorescence detection with 532nm Nd:YAG laser

    International Nuclear Information System (INIS)

    Vrabel, Patrik; Taborsky, Petr; Ryvolova, Marketa; Havel, Josef; Preisler, Jan

    2006-01-01

    Capillary electrophoresis with laser-induced fluorescence detection (CELIF) is a powerful tool for separation and sensitive determination of fluorescent species. Biologically active compounds, such as amino acids, peptides and proteins may exhibit native fluorescence, which is however often low and/or an expensive laser is required for excitation in UV. Therefore, labelling of the analytes with a fluorescent dye is usually necessary. In this work, a home-built CELIF instrument with diode pumped frequency-doubled continuous wave Nd:YAG excitation laser with feedback power regulation (532nm) was constructed. The suitability of this type of laser for LIF detection in a separation method was found excellent. A limit of detection (LOD) (S/N=3) of 2x10 -13 mol/l was achieved with rhodamine B, which is comparable to those obtained using similar instruments with Ar + laser [Y.F. Cheng, N.J. Dovichi, Science 242 (1988) 562, E.S. Yeung et al., J. Chromatogr. 608 (1992) 73]. LOD of a protein derivatized according to modified procedures [M.J. Little et al., Anal. Chim. Acta 339 (1997) 279, A. Chersi et al., Biochim. Biophys. Acta 1336 (1997) 83] was determined. Detection of the derivatives was found to be limited by insufficient reaction recovery at low analyte concentration, chemical noise, separation efficiency and quality of the derivatizing reagent rather than by the detector performance. As a consequence, a huge gap between the detection ability of CELIF instruments and LOD determined in real samples is revealed

  16. A comparison of ion beam measurements by retarding field energy analyzer and laser induced fluorescence in helicon plasma devices

    Energy Technology Data Exchange (ETDEWEB)

    Gulbrandsen, N., E-mail: njal.gulbrandsen@uit.no; Fredriksen, Å. [Department of Physics and Technology, UiT The Arctic University of Norway, 9037 Tromsø (Norway); Carr, J. [Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506 (United States); Department of Physics, Texas Lutheran University, Seguin, Texas 78155 (United States); Scime, E. [Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506 (United States)

    2015-03-15

    Both Laser-Induced Fluorescence (LIF) and Retarding Field Energy Analyzers (RFEA) have been applied to the investigation of beams formed in inductively coupled helicon plasmas. While the LIF technique provides a direct measurement of the velocity distribution in the plasma, the RFEA measures ion flux as a function of a retarding potential. In this paper, we present a method to compare the two techniques, by converting the LIF velocity distribution to an equivalent of a RFEA measurement. We applied this method to compare new LIF and RFEA measurements in two different experiments; the Hot Helicon Experiment (HELIX) - Large Experiment on Instabilities and Anisotropies (LEIA) at West Virginia University and Njord at University of Tromsø. We find good agreement between beam energies of the two methods. In agreement with earlier observations, the RFEA is found to measure ion beams with densities too low for the LIF to resolve. In addition, we present measurements of the axial development of the ion beam in both experiments. Beam densities drop exponentially with distance from the source, both in LIF and RFEA measurements. The effective quenching cross section from LIF in LEIA is found to be σ{sub b,*}=4×10{sup −19} m{sup 2}, and the effective beam collisional cross sections by RFEA in Njord to be σ{sub b}=1.7×10{sup −18} m{sup 2}.

  17. Laser-induced fluorescence measurements of argon and xenon ion velocities near the sheath boundary in 3 ion species plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Yip, Chi-Shung; Hershkowitz, Noah [Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Severn, Greg [Department of Physics, University of San Diego, San Diego, California 92110 (United States); Baalrud, Scott D. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States)

    2016-05-15

    The Bohm sheath criterion is studied with laser-induced fluorescence in three ion species plasmas using two tunable diode lasers. Krypton is added to a low pressure unmagnetized DC hot filament discharge in a mixture of argon and xenon gas confined by surface multi-dipole magnetic fields. The argon and xenon ion velocity distribution functions are measured at the sheath-presheath boundary near a negatively biased boundary plate. The potential structures of the plasma sheath and presheath are measured by an emissive probe. Results are compared with previous experiments with Ar–Xe plasmas, where the two ion species were observed to reach the sheath edge at nearly the same speed. This speed was the ion sound speed of the system, which is consistent with the generalized Bohm criterion. In such two ion species plasmas, instability enhanced collisional friction was demonstrated [Hershkowitz et al., Phys. Plasmas 18(5), 057102 (2011).] to exist which accounted for the observed results. When three ion species are present, it is demonstrated under most circumstances the ions do not fall out of the plasma at their individual Bohm velocities. It is also shown that under most circumstances the ions do not fall out of the plasma at the system sound speed. These observations are also consistent with the presence of the instabilities.

  18. A Laser-Induced Fluorescence Instrument for Aircraft Measurements of Sulfur Dioxide in the Upper Troposphere and Lower Stratosphere

    Science.gov (United States)

    Rollins, Andrew W.; Thornberry, Troy D.; Ciciora, Steven J.; McLaughlin, Richard J.; Watts, Laurel A.; Hanisco, Thomas F.; Baumann, Esther; Giorgetta, Fabrizio R.; Bui, Thaopaul V.; Fahey, David W.

    2016-01-01

    This work describes the development and testing of a new instrument for in situ measurements of sulfur dioxide (SO2) on airborne platforms in the upper troposphere and lower stratosphere (UTLS). The instrument is based on the laser-induced fluorescence technique and uses the fifth harmonic of a tunable fiber-amplified semiconductor diode laser system at 1084.5 nm to excite SO2 at 216.9 nm. Sensitivity and background checks are achieved in flight by additions of SO2 calibration gas and zero air, respectively. Aircraft demonstration was performed during the NASA Volcano Plume Investigation Readiness and Gas-Phase and Aerosol Sulfur (VIRGAS) experiment, which was a series of flights using the NASA WB-57F during October 2015 based at Ellington Field and Harlingen, Texas. During these flights, the instrument successfully measured SO2 in the UTLS at background (non-volcanic) conditions with a precision of 2 ppt at 10 s and an overall uncertainty determined primarily by instrument drifts of +/- (16% + 0.9 ppt).

  19. Direct measurement of the concentration of metastable ions produced from neutral gas particles using laser-induced fluorescence

    Science.gov (United States)

    Chu, Feng; Skiff, Fred; Berumen, Jorge; Mattingly, Sean; Hood, Ryan

    2017-10-01

    Extensive information can be obtained on wave-particle interactions and wave fields by direct measurement of perturbed ion distribution functions using laser-induced fluorescence (LIF). For practical purposes, LIF is frequently performed on metastables that are produced from neutral gas particles and existing ions in other electronic states. We numerically simulate the ion velocity distribution measurement and wave-detection process using a Lagrangian model for the LIF signal. The results show that under circumstances where the metastable ion population is coming directly from the ionization of neutrals (as opposed to the excitation of ground-state ions), the velocity distribution will only faithfully represent processes which act on the ion dynamics in a time shorter than the metastable lifetime. Therefore, it is important to know the ratio of metastable population coming from neutrals to that from existing ions to correct the LIF measurements of plasma ion temperature and electrostatic waves. In this paper, we experimentally investigate the ratio of these two populations by externally launching an ion acoustic wave and comparing the wave amplitudes that are measured with LIF and a Langmuir probe using a lock-in amplifier. DE-FG02-99ER54543.

  20. A case study comparing the use of laser induced fluorescence with cone penetrometer testing to more conventional screening methods

    International Nuclear Information System (INIS)

    Earley, K.; Rapp, K.

    1995-01-01

    Site assessments utilizing in-situ techniques to characterize subsurface stratigraphy and contaminant distribution are becoming more accepted and commonly used. Laser Induced Fluorescence (LIF) spectroscopy with Cone Penetrometer Test (CPT) is a new technology that provides real-time data on stratigraphy and petroleum hydrocarbons (PHCs) in the subsurface environment. Over the last two years, LIF technological advances have led to field equipment with improved durability, reduced bulk and weight, and the ability to integrate LIF systems with CPT equipment. The Rapid Optical Screening Tool (a Unisys registered trademark hereafter referred to as ROST) presents the development of an in-situ data collection system which couples state-of-the-art LIF technology with CPT. ROST/CPT technology has recently been utilized in a variety of field and soil conditions. These advances, along with the need for rapid in-situ information on the horizontal and vertical distribution of petroleum hydrocarbons (PHCs) have resulted in equipment that is now available for commercial applications. This paper presents a comparison of ROST/CPT to more conventional characterization methods at a manufacturing site in Nebraska. Various PHCs were stored in underground and above ground storage tanks across the site. One of these PHC spill areas consisting of a mixture of diesel fuel oil and kerosene was selected for a comparative study between various site assessment methods

  1. Two-photon absorption laser-induced fluorescence of atomic oxygen in the afterglow of pulsed positive corona discharge

    Science.gov (United States)

    Ono, Ryo; Takezawa, Kei; Oda, Tetsuji

    2009-08-01

    Atomic oxygen is measured in the afterglow of pulsed positive corona discharge using time-resolved two-photon absorption laser-induced fluorescence. The discharge occurs in a 14 mm point-to-plane gap in dry air. After the discharge pulse, the atomic oxygen density decreases at a rate of 5×104 s-1. Simultaneously, ozone density increases at almost the same rate, where the ozone density is measured using laser absorption method. This agreement between the increasing rate of atomic oxygen and decreasing rate of ozone proves that ozone is mainly produced by the well-known three-body reaction, O+O2+M→O3+M. No other process for ozone production such as O2(v)+O2→O3+O is observed. The spatial distribution of atomic oxygen density is in agreement with that of the secondary streamer luminous intensity. This agreement indicates that atomic oxygen is mainly produced in the secondary streamer channels, not in the primary streamer channels.

  2. Spatially and Temporally Resolved Atomic Oxygen Measurements in Short Pulse Discharges by Two Photon Laser Induced Fluorescence

    Science.gov (United States)

    Lempert, Walter; Uddi, Mruthunjaya; Mintusov, Eugene; Jiang, Naibo; Adamovich, Igor

    2007-10-01

    Two Photon Laser Induced Fluorescence (TALIF) is used to measure time-dependent absolute oxygen atom concentrations in O2/He, O2/N2, and CH4/air plasmas produced with a 20 nanosecond duration, 20 kV pulsed discharge at 10 Hz repetition rate. Xenon calibrated spectra show that a single discharge pulse creates initial oxygen dissociation fraction of ˜0.0005 for air like mixtures at 40-60 torr total pressure. Peak O atom concentration is a factor of approximately two lower in fuel lean (φ=0.5) methane/air mixtures. In helium buffer, the initially formed atomic oxygen decays monotonically, with decay time consistent with formation of ozone. In all nitrogen containing mixtures, atomic oxygen concentrations are found to initially increase, for time scales on the order of 10-100 microseconds, due presumably to additional O2 dissociation caused by collisions with electronically excited nitrogen. Further evidence of the role of metastable N2 is demonstrated from time-dependent N2 2^nd Positive and NO Gamma band emission spectroscopy. Comparisons with modeling predictions show qualitative, but not quantitative, agreement with the experimental data.

  3. Photodissociation dynamics of 2-chloro-6-nitrotoluene and nitrocyclopentane in gas phase: Laser-induced fluorescence detection of OH

    Science.gov (United States)

    Kawade, Monali N.; Saha, Ankur; Upadhyaya, Hari P.; Kumar, Awadhesh; Naik, Prakash D.

    2014-10-01

    Photodissociation of 2-chloro-6-nitrotoluene (ClNT) at 193, 248 and 266 nm and nitrocyclopentane (NCP) at 193 nm leads to the formation of OH, as detected by laser-induced fluorescence (LIF). The nascent OH produced from the photolysis of ClNT at all the wavelengths is vibrationally cold, with the Boltzmann type rotational state distributions. However, the nascent OH product from NCP is in the ground and vibrationally excited states with the measured average relative population in ν″ = 1 to that in ν″ = 0 of 0.12 ± 0.03, and these levels are characterized by rotational temperatures of 650 ± 180 K and 1570 ± 90 K, respectively. The translational energy partitioned in the OH fragment has been measured for photodissociation of both ClNT and NCP. On the basis of both the experimental results and the ground state molecular orbital (MO) calculations, a plausible mechanism for the OH formation has been proposed.

  4. Laser induced fluorescence of TiD: analysis of the B4Γ-X4Φ transition

    International Nuclear Information System (INIS)

    Danielsson, M

    2007-01-01

    A titanium hollow cathode lamp in combination with a dye laser and a monochromator has been used to resolve the laser-induced fluorescence of the TiD molecule. This has enabled the extension of the earlier rotational analysis of the (0,0) band of the B 4 Γ-X 4 Φ transition. In addition, the (1,1) band and part of the (2,2) band have been observed and analyzed. All earlier works on the TiD and TiH molecules concern the (0,0) band. The present work is the first to report experimentally determined equilibrium constants for TiD. For the ground state X 4 Φ the principal parameters are (in cm -1 ) A e =33.075, B e =2.7804, D e =6.819x10 -5 and α e =0.0466. By using the isotope relationships the corresponding equilibrium parameters for the TiH molecule are given

  5. Two-dimensional capillary electrophoresis: capillary isoelectric focusing and capillary zone electrophoresis with laser-induced fluorescence detection

    Science.gov (United States)

    Dickerson, Jane A.; Ramsay, Lauren M.; Dada, Oluwatosin O.; Cermak, Nathan

    2011-01-01

    Capillary isoelectric focusing and capillary zone electrophoresis are coupled with laser-induced fluorescence detection to create an ultrasensitive two-dimensional separation method for proteins. In this method, two capillaries are joined through a buffer filled interface. Separate power supplies control the potential at the injection end of the first capillary and at the interface; the detector is held at ground potential. Proteins are labeled with the fluorogenic reagent Chromeo P503, which preserves the isoelectric point of the labeled protein. The labeled proteins were mixed with ampholytes and injected into the first dimension capillary. A focusing step was performed with the injection end of the capillary at high pH and the interface at low pH. To mobilize components, the interface was filled with a high pH buffer, which was compatible with the second dimension separation. A fraction was transferred to the second dimension capillary for separation. The process of fraction transfer and second dimension separation was repeated two dozen times. The separation produced a spot capacity of 125. PMID:20603830

  6. Visualizing and quantifying dose distribution in a UV reactor using three-dimensional laser-induced fluorescence.

    Science.gov (United States)

    Gandhi, Varun N; Roberts, Philip J W; Kim, Jae-Hong

    2012-12-18

    Evaluating the performance of typical water treatment UV reactors is challenging due to the complexity in assessing spatial and temporal variation of UV fluence, resulting from highly unsteady, turbulent nature of flow and variation in UV intensity. In this study, three-dimensional laser-induced fluorescence (3DLIF) was applied to visualize and quantitatively analyze a lab-scale UV reactor consisting of one lamp sleeve placed perpendicular to flow. Mapping the spatial and temporal fluence delivery and MS2 inactivation revealed the highest local fluence in the wake zone due to longer residence time and higher UV exposure, while the lowest local fluence occurred in a region near the walls due to short-circuiting flow and lower UV fluence rate. Comparing the tracer based decomposition between hydrodynamics and IT revealed similar coherent structures showing the dependency of fluence delivery on the reactor flow. The location of tracer injection, varying the height and upstream distance from the lamp center, was found to significantly affect the UV fluence received by the tracer. A Lagrangian-based analysis was also employed to predict the fluence along specific paths of travel, which agreed with the experiments. The 3DLIF technique developed in this study provides new insight on dose delivery that fluctuates both spatially and temporally and is expected to aid design and optimization of UV reactors as well as validate computational fluid dynamics models that are widely used to simulate UV reactor performances.

  7. Investigation of excited states populations density of Hall thruster plasma in three dimensions by laser-induced fluorescence spectroscopy

    Science.gov (United States)

    Krivoruchko, D. D.; Skrylev, A. V.

    2018-01-01

    The article deals with investigation of the excited states populations distribution of a low-temperature xenon plasma in the thruster with closed electron drift at 300 W operating conditions were investigated by laser-induced fluorescence (LIF) over the 350-1100 nm range. Seven xenon ions (Xe II) transitions were analyzed, while for neutral atoms (Xe I) just three transitions were explored, since the majority of Xe I emission falls into the ultraviolet or infrared part of the spectrum and are difficult to measure. The necessary spontaneous emission probabilities (Einstein coefficients) were calculated. Measurements of the excited state distribution were made for points (volume of about 12 mm3) all over the plane perpendicular to thruster axis in four positions on it (5, 10, 50 and 100 mm). Measured LIF signal intensity have differences for each location of researched point (due to anisotropy of thruster plume), however the structure of states populations distribution persisted at plume and is violated at the thruster exit plane and cathode area. Measured distributions show that for describing plasma of Hall thruster one needs to use a multilevel kinetic model, classic model can be used just for far plume region or for specific electron transitions.

  8. Supersonic pulsed free-jet of atoms and molecules of refractory metals: laser induced fluorescence spectroscopic studies on zirconium atoms and zirconium oxide molecules

    International Nuclear Information System (INIS)

    Nakhale, S.G.

    2004-11-01

    The experimental setup for generating supersonic pulsed free-jet containing atoms and molecules of refractory nature has been built. The technique of laser vaporization in conjunction with supersonic cooling is used to generate these species. The cooled atoms and molecules in supersonic free-jet are probed by laser induced fluorescence spectroscopy. In particular, the technique has been used to perform low-resolution laser induced fluorescence spectroscopy, limited by laser linewidth, on cold Zr atoms and ZrO molecules. The translational temperatures of ∼ 26.5 K and the rotational temperatures of ∼ 81 K have been achieved. It is possible to achieve the Doppler width of few tens of MHz allowing it to perform high-resolution spectroscopy on these atomic and molecular species. Also because of low rotational temperature of molecules the spectral congestion is greatly reduced. In general, this technique can be applied to perform spectroscopy on atoms and molecules of refractory nature. (author)

  9. High-Resolution Spectroscopy of Laser Ablation Plumes Using Laser-Induced Fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Harilal, Sivanandan S.; LaHaye, Nicole L.; Phillips, Mark C.

    2017-02-06

    We used a CW laser as a narrow-band (~50kHz) tunable LIF excitation source to probe absorption from selected atomic transitions (Al, U etc. ) in a ns laser ablation plume. A comparison of fluorescence signal with respect to emission spectroscopy show significant increase in the magnitude and persistence from selected Al and U transitions in a LIBS plume. The high spectral resolution provided by the LIF measurement allows peaks to be easily separated even if they overlap in the emission spectra.

  10. Tracer-based laser-induced fluorescence measurement technique for quantitative fuel/air-ratio measurements in a hydrogen internal combustion engine.

    Science.gov (United States)

    Blotevogel, Thomas; Hartmann, Matthias; Rottengruber, Hermann; Leipertz, Alfred

    2008-12-10

    A measurement technique for the quantitative investigation of mixture formation processes in hydrogen internal combustion engines (ICEs) has been developed using tracer-based laser-induced fluorescence (TLIF). This technique can be employed to fired and motored engine operation. The quantitative TLIF fuel/air-ratio results have been verified by means of linear Raman scattering measurements. Exemplary results of the simultaneous investigation of mixture formation and combustion obtained at an optical accessible hydrogen ICE are shown.

  11. Optical scanner system for high resolution measurement of lubricant distributions on metal strips based on laser induced fluorescence

    Science.gov (United States)

    Holz, Philipp; Lutz, Christian; Brandenburg, Albrecht

    2017-06-01

    We present a new optical setup, which uses scanning mirrors in combination with laser induced fluorescence to monitor the spatial distribution of lubricant on metal sheets. Current trends in metal processing industry require forming procedures with increasing deformations. Thus a welldefined amount of lubricant is necessary to prevent the material from rupture, to reduce the wearing of the manufacturing tool as well as to prevent problems in post-deforming procedures. Therefore spatial resolved analysis of the thickness of lubricant layers is required. Current systems capture the lubricant distribution by moving sensor heads over the object along a linear axis. However the spatial resolution of these systems is insufficient at high strip speeds, e.g. at press plants. The presented technology uses fast rotating scanner mirrors to deflect a laser beam on the surface. This 405 nm laser light excites the autofluorescence of the investigated lubricants. A coaxial optic collects the fluorescence signal which is then spectrally filtered and recorded using a photomultiplier. From the acquired signal a two dimensional image is reconstructed in real time. This paper presents the sensor setup as well as its characterization. For the calibration of the system reference targets were prepared using an ink jet printer. The presented technology for the first time allows a spatial resolution in the millimetre range at production speed. The presented test system analyses an area of 300 x 300 mm² at a spatial resolution of 1.1 mm in less than 20 seconds. Despite this high speed of the measurement the limit of detection of the system described in this paper is better than 0.05 g/m² for the certified lubricant BAM K-009.

  12. Measurements of a potential interference with laser-induced fluorescence measurements of ambient OH from the ozonolysis of biogenic alkenes

    Science.gov (United States)

    Rickly, Pamela; Stevens, Philip S.

    2018-01-01

    Reactions of the hydroxyl radical (OH) play a central role in the chemistry of the atmosphere, and measurements of its concentration can provide a rigorous test of our understanding of atmospheric oxidation. Several recent studies have shown large discrepancies between measured and modeled OH concentrations in forested areas impacted by emissions of biogenic volatile organic compounds (BVOCs), where modeled concentrations were significantly lower than measurements. A potential reason for some of these discrepancies involves interferences associated with the measurement of OH using the laser-induced fluorescence-fluorescence assay by gas expansion (LIF-FAGE) technique in these environments. In this study, a turbulent flow reactor operating at atmospheric pressure was coupled to a LIF-FAGE cell and the OH signal produced from the ozonolysis of α-pinene, β-pinene, ocimene, isoprene, and 2-methyl-3-buten-2-ol (MBO) was measured. To distinguish between OH produced from the ozonolysis reactions and any OH artifact produced inside the LIF-FAGE cell, an external chemical scrubbing technique was used, allowing for the direct measurement of any interference. An interference under high ozone (between 2 × 1013 and 10 × 1013 cm-3) and BVOC concentrations (between approximately 0.1 × 1012 and 40 × 1012 cm-3) was observed that was not laser generated and was independent of the ozonolysis reaction time. For the ozonolysis of α- and β-pinene, the observed interference accounted for approximately 40 % of the total OH signal, while for the ozonolysis of ocimene the observed interference accounted for approximately 70 % of the total OH signal. Addition of acetic acid to the reactor eliminated the interference, suggesting that the source of the interference in these experiments involved the decomposition of stabilized Criegee intermediates (SCIs) inside the FAGE detection cell. Extrapolation of these measurements to ambient concentrations suggests that these interferences

  13. Measurement of interferences associated with the detection of the hydroperoxy radical in the atmosphere using laser-induced fluorescence

    Science.gov (United States)

    Lew, Michelle M.; Dusanter, Sebastien; Stevens, Philip S.

    2018-01-01

    One technique used to measure concentrations of the hydroperoxy radical (HO2) in the atmosphere involves chemically converting it to OH by addition of NO and subsequent detection of OH. However, some organic peroxy radicals (RO2) can also be rapidly converted to HO2 (and subsequently OH) in the presence of NO, interfering with measurements of ambient HO2 radical concentrations. This interference must be characterized for each instrument to determine to what extent various RO2 radicals interfere with measurements of HO2 and to assess the impact of this interference on past measurements. The efficiency of RO2-to-HO2 conversion for the Indiana University laser-induced fluorescence-fluorescence assay by gas expansion (IU-FAGE) instrument was measured for a variety of RO2 radicals. Known quantities of OH and HO2 radicals were produced from the photolysis of water vapor at 184.9 nm, and RO2 radicals were produced by the reaction of several volatile organic compounds (VOCs) with OH. The conversion efficiency of RO2 radicals to HO2 was measured when NO was added to the sampling cell for conditions employed during several previous field campaigns. For these conditions, approximately 80 % of alkene-derived RO2 radicals and 20 % of alkane-derived RO2 radicals were converted to HO2. Based on these measurements, interferences from various RO2 radicals contributed to approximately 35 % of the measured HO2 signal during the Mexico City Metropolitan Area (MCMA) 2006 campaign (MCMA-2006), where the measured VOCs consisted of a mixture of saturated and unsaturated species. However, this interference can contribute more significantly to the measured HO2 signal in forested environments dominated by unsaturated biogenic emissions such as isoprene.

  14. Identification Of Natural Dyes On Archaeological Textile Objects Using Laser Induced Fluorescent Technique

    International Nuclear Information System (INIS)

    Abdel-Kareem, O.; Eltokhy, A.; Harith, M. A.

    2011-01-01

    This study aims to evaluate the use of Laser Fluorescent as a non-destructive technique for identification of natural dyes on archaeological textile objects. In this study wool textile samples were dyed with 10 natural dyes such as cochineal, cutch, henna, indigo, Lac, madder, safflower, saffron, sumac and turmeric. These dyes common present on archaeological textile objects to be used as standard dyed textile samples. These selected natural dyes will be used as known references that can be used a guide to identify unknown archaeological dyes. The dyed textile samples were investigated with laser radiation in different wavelengths to detect the best wavelengths for identification each dye. This study confirms that Laser Florescent is very useful and a rapid technique can be used as a non-destructive technique for identification of natural dyes on archaeological textile objects. The results obtained with this study can be a guide for all conservators in identification of natural organic dyes on archaeological textile objects.

  15. Identification Of Natural Dyes On Archaeological Textile Objects Using Laser Induced Fluorescent Technique

    Science.gov (United States)

    Abdel-Kareem, O.; Eltokhy, A.; Harith, M. A.

    2011-09-01

    This study aims to evaluate the use of Laser Fluorescent as a non-destructive technique for identification of natural dyes on archaeological textile objects. In this study wool textile samples were dyed with 10 natural dyes such as cochineal, cutch, henna, indigo, Lac, madder, safflower, saffron, sumac and turmeric. These dyes common present on archaeological textile objects to be used as standard dyed textile samples. These selected natural dyes will be used as known references that can be used a guide to identify unknown archaeological dyes. The dyed textile samples were investigated with laser radiation in different wavelengths to detect the best wavelengths for identification each dye. This study confirms that Laser Florescent is very useful and a rapid technique can be used as a non-destructive technique for identification of natural dyes on archaeological textile objects. The results obtained with this study can be a guide for all conservators in identification of natural organic dyes on archaeological textile objects.

  16. Development of the Megahertz Planar Laser-induced Fluorescence Diagnostic for Plasma Turbulence Visualization

    International Nuclear Information System (INIS)

    Kuritsyn, Aleksey; Levinton, Fred M.

    2004-01-01

    A megahertz LIF-based diagnostic system for measuring ion density fluctuations in two spatial dimensions is described. Well resolved spatial and temporal 2D images of turbulent structures will be useful in understanding ion turbulence in magnetically confined plasmas which is a key factor in the performance of fusion experimental devices. A sheet beam of a megahertz repetition rate tunable Alexandrite laser is used to excite ion emission from argon plasma. The fluorescence emitted from the plane of the laser beam is detected with a narrow band interference filter and intensified ultra-fast CCD camera providing 2D images of relative ion density fluctuations every microsecond. It is expected that the edge plasma on fusion devices will be accessible to this technique

  17. The use of vitamins as tracer dyes for laser-induced fluorescence in liquid flow applications

    Science.gov (United States)

    Zähringer, Katharina

    2014-04-01

    Tracers commonly used in experimental flow studies are mostly nocuous to the environment and human health. Particularly, in large flow installations, this can become a problem. In this study, a solution of this problem is presented, based on using water-soluble vitamins. Five of them are examined here for their applicability in flow studies. Vitamins B2 and B6 turned out to be the most promising candidates, and the dependency of their fluorescence intensity on parameters like concentration, laser energy, temperature, and pH are determined for two commonly used laser excitation wavelengths (532, 355 nm). Two examples of application in a static mixer and a spray flow are shown and demonstrate the applicability of the vitamin tracers.

  18. Enantioseparations of amino acids by capillary array electrophoresis with 532 nm laser induced fluorescence detection.

    Science.gov (United States)

    Liu, Kaiying; Wang, Li

    2013-06-21

    Capillary array electrophoresis (CAE) is a promising technique for multiple enantiomeric separations. Carboxytetramethylrhodamine succinimidyl ester (TAMRA SE), a rhodamine-core fluorescent probe, has rarely been applied as an original precolumn derivatization reagent for chiral amino acid (AA) analysis so far. For these purposes, high-throughput enantiomeric separations of 12 TAMRA SE-AAs by a home-made 532 nm CAE-LIF scanner are presented. The effect of cyclodextrins (CDs) and a variety of organic modifiers was quickly investigated. Baseline separations were achieved in 100 mM Tris-borate buffer (pH 10.0) containing 2 mM β-CD and 10 mM hexamethylenediamine (HDA). Multiple determination of the enantiomeric excess (ee) in non-racemic mixtures of alanine is successfully presented. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. A very thin light sheet technique used to investigate meniscus shapes by laser induced fluorescence

    International Nuclear Information System (INIS)

    Khan, M.A.

    2003-01-01

    In this paper a light sheet technique is described to accurately (50 μm) measure meniscus profiles in film formation problems. The use of a slit to create the thin (0.1 mm) laser sheet makes the technique easy to implement, and allows tunable sheet thickness. The low light intensity obtained through the slit is compensated by the induced fluorescence of the tested fluid, which provides good picture contrast. After video recording through a microscope, the actual meniscus is recovered by image processing and proper calibration. The efficiency of the technique is demonstrated on a coating flow experiment. Due to its good accuracy and ease of use, this technique is expected to provide useful quantitative information about meniscus problems, in particular for the validation of computational fluid dynamics CFD solutions of coating flows. (author)

  20. Laser diagnostics in combustion. Elastic scattering and picosecond laser-induced fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Ossler, Frederik

    1999-05-01

    Elastic scattering and the Lorenz-Mie (LM) theory in particular is used for the characterization of sub-micron- and micron-sized droplets of organic fuels in sprays and aerosols. Calculations on the Lorenz-Mie theory show that backward-sideward scattered visible radiation can be used for unambiguous detection of ensembles of homogeneous droplets of organic substances with diameters around 1 micrometer (size parameter between 2 and 6). A backward feature in the polarization ratio appears with a value considerably higher than one, on the opposite to the case of the rainbow observed for larger droplets. A comparison between measurements and LM calculations showed that a large amount of droplets in aerosols and well-atomized sprays were smaller than one micrometer in diameter. The LM theory was also used to characterize different size groups in a burning spray. A 3 - D technique based on a picosecond laser and a streak camera was demonstrated for measurements of fast and turbulent biphase flows. The entire 3 - D information was obtained within a time-span of less than 15 nanoseconds. A 2 - D technique for lifetime measurements based on a picosecond laser and a streak camera has been demonstrated on static objects. An analysis indicates that the technique may be applied to measurements of lifetimes around or below one picosecond employing femtosecond lasers and femtosecond streak-cameras. The technique may in principle be used to study dynamic systems when two detectors are used. Fluorescence lifetime measurements on hydrogen and oxygen atoms in flames at atmospheric pressure demonstrate the need of lasers with suiting spectral properties such as jitter and linewidth and the need of detectors with high sensitivity in the near IR in the case of oxygen atoms. The fluorescence lifetimes of gas phase acetone and 3-pentanone at 266 nm excitation wavelength have been measured for mixtures with nitrogen and air at temperatures between 323 and 723 K and pressures between 0

  1. Detection of low-concentration ammonia using differential laser-induced fluorescence on vapochromic coordination polymers

    Science.gov (United States)

    Yin, Dawei; Chapman, Glenn H.; Stevens, David; Gray, Bonnie; Leznoff, Daniel

    2018-02-01

    The detection of ammonia in parts per millions range has been challenging in sensors research, and is of great importance for industrial applications. In previous literature, Vapochromic Coordination Polymers (VCP) were developed to achieve luminescence upon a targeted gas exposures. We investigate a specific VCP, Zn[Au(CN)2]2,as an ammonia sensing material. Upon high concentration ammonia exposure, the fluorescent peak under near-UV stimulation undergoes a spectral shift from 460nm to 520nm, while the intensity increases by 3 4X. However, at ammonia concentrations portable spectrometer (Photon Control SPM-002), and processed the data by separating the spectrum into two regions; (A) from 425 nm to 460 nm and (B) from 460nm to 500nm. Next, the integrated emissions under both regions were computed, and the value of shorter wavelength region (A) was subtracted from the longer wavelength one (B). When exposed to ammonia, region (A) reduces overall intensity while region (B) increases, resulting a signal starting from negative value and gradually increases to positive values, enabling the detection of 5ppm ammonia in less than 30 seconds gas exposure.

  2. Determination of magnetic field direction in tokamaks from laser-induced Lyman-α fluorescence

    International Nuclear Information System (INIS)

    Voslamber, D.

    1988-04-01

    Resonant laser scattering in the Lyman-α line of hydrogen is investigated as a possible tool for measuring the magnetic field direction in tokamak plasmas. The method is based on the depolarisation-dependence of the scattering process. Limitations arising from depolarising collisions are studied in detail by employing a previously developed theory for the collisional redistribution of light. An error analysis is performed to derive the expected experimental precision under various plasma conditions and for laser energies ranging between 1 micronJ and 10 mJ. This analysis also includes the measurement of neutral hydrogen densities. It is shown that with presently available laser powers application of the method would be restricted to the border regions of the plasma. Application to the central regions would require further developments in laser technology, especially with regard to higher powers at the wavelength of Lyman-α and (or) to fast repetition rates

  3. Multilinear analysis of Time-Resolved Laser-Induced Fluorescence Spectra of U(VI containing natural water samples

    Directory of Open Access Journals (Sweden)

    Višňák Jakub

    2017-01-01

    Full Text Available Natural waters’ uranium level monitoring is of great importance for health and environmental protection. One possible detection method is the Time-Resolved Laser-Induced Fluorescence Spectroscopy (TRLFS, which offers the possibility to distinguish different uranium species. The analytical identification of aqueous uranium species in natural water samples is of distinct importance since individual species differ significantly in sorption properties and mobility in the environment. Samples originate from former uranium mine sites and have been provided by Wismut GmbH, Germany. They have been characterized by total elemental concentrations and TRLFS spectra. Uranium in the samples is supposed to be in form of uranyl(VI complexes mostly with carbonate (CO32− and bicarbonate (HCO3− and to lesser extend with sulphate (SO42− , arsenate (AsO43− , hydroxo (OH− , nitrate (NO3− and other ligands. Presence of alkaline earth metal dications (M = Ca2+ , Mg2+ , Sr2+ will cause most of uranyl to prefer ternary complex species, e.g. Mn(UO2(CO332n-4 (n ∊ {1; 2}. From species quenching the luminescence, Cl− and Fe2+ should be mentioned. Measurement has been done under cryogenic conditions to increase the luminescence signal. Data analysis has been based on Singular Value Decomposition and monoexponential fit of corresponding loadings (for separate TRLFS spectra, the “Factor analysis of Time Series” (FATS method and Parallel Factor Analysis (PARAFAC, all data analysed simultaneously. From individual component spectra, excitation energies T00, uranyl symmetric mode vibrational frequencies ωgs and excitation driven U-Oyl bond elongation ΔR have been determined and compared with quasirelativistic (TDDFT/B3LYP theoretical predictions to cross -check experimental data interpretation.

  4. A Lagrangian model for laser-induced fluorescence and its application to measurements of plasma ion temperature and electrostatic waves

    Science.gov (United States)

    Chu, F.; Skiff, F.

    2018-01-01

    Extensive information can be obtained on wave-particle interactions and wave fields by a direct measurement of perturbed ion distribution functions using laser-induced fluorescence (LIF). For practical purposes, LIF is frequently performed on metastable states that are produced from neutral gas particles and ions in other electronic states. If the laser intensity is increased to obtain a better LIF signal, then optical pumping can produce systematic effects depending on the collision rates which control metastable population and lifetime. We numerically simulate the ion velocity distribution measurement and wave-detection process using a Lagrangian model for the LIF signal for the case where metastables are produced directly from neutrals. This case requires more strict precautions and is important for discharges with energetic primary electrons and a high density of neutrals. Some of the results also apply to metastables produced from pre-existing ions. The simulations show that optical pumping broadening affects the ion velocity distribution function f0(v) and its first-order perturbation f1(v,t) when the laser intensity is increased above a certain level. The results also suggest that ion temperature measurements are only accurate when the metastable ions can live longer than the ion-ion collision mean free time. For the purposes of wave detection, the wave period has to be significantly shorter than the lifetime of metastable ions for a direct interpretation. It is more generally true that metastable ions may be viewed as test-particles. As long as an appropriate model is available, LIF can be extended to a range of environments.

  5. Application of the laser induced fluorescence to the investigation of highly magnetized plasmas, heated by ion cyclotron resonance

    International Nuclear Information System (INIS)

    Pailloux, A.

    1997-01-01

    This work has been achieved in the frame of isotopic separation studies by in cyclotron resonance. For this purpose, in a highly magnetized (2 to 3 Tesla) and non-collisional (10 12 ions/cm 3 ) plasma, composed of metallic ions, a wave near the ion cyclotron frequency is thrown in order to heat selectively a given species. A laser induced fluorescence (LIP) has been developed on barium and gadolinium plasmas. The Larmor gyration of ions greatly modifies the interaction, which has been modelled through the time-dependent Schroedinger equation. The obtained excitation probably has been integrated over all the ions excited in the measurement volume in order to check that the LIF still leads to the distribution function of ion velocities. The influence of the Larmor motion of ions on the spectral distribution of LIF has been derived both theoretically and experimentally. The LIF diagnostics has been achieved with a dye O'ring laser. The barium ion has been excited on the transition 6142 angstrom, using rhodamine 6G dye, and the gadolinium ion on the pseudo-triplet 3861 angstrom, using exalite dye. Data treatment has been developed taking into account the Zeeman effect and the different heating of isotopes. The ionic temperature (from 1 eV to some hundreds eV) has been measured as a function of radiofrequency heating. Our experimental results are in good agreement with the selective heating theory. Also, the ion velocity distribution function has been found locally Maxwellian. And the behaviour of the plasma has been studied as a function of control parameters of the plasma source. (author)

  6. Measurement of spatially resolved gas-phase plasma temperatures by optical emission and laser-induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Davis, G.P.; Gottscho, R.A.

    1983-01-01

    Knowledge of the energy distributions of particles in glow discharges is crucial to the understanding and modeling of plasma reactors used in microelectronic manufacturing. Reaction rates, available product channels, and transport phenomena all depend upon the partitioning of energy in the discharge. Because of the nonequilibrium nature of glow discharges, however, the distribution of energy among different species and among different degrees of freedom cannot be characterized simply by one temperature. The extent to which different temperatures are needed for each degree of freedom and for each species is not known completely. How plasma operating conditions affect these energy distributions is also an unanswered question. We have investigated the temperatures of radicals, ions, and neutrals in CCl 4 , CCl 4 /N 2 (2%), and N 2 discharges. In the CCl 4 systems, we probed the CCl rotational and vibrational energy distributions by laser-induced fluorescence spectroscopy. The rotational distribution always appeared to be thermal but under identical operating conditions was found to be roughly-equal400 K colder than the vibrational distribution. The rotational temperature at any point in the discharge was strongly dependent upon both applied power and surface temperature. Thermal gradients as large as 10 2 K mm -1 were observed near electrode surfaces but the bulk plasmas were isothermal. When 2% N 2 was added to a CCl 4 discharge, N 2 second positive emission was observed and used to estimate the N 2 rotational temperature. The results suggest that emission from molecular actinometers can be used to measure plasma temperatures, providing such measurements are not made in close proximity to surfaces

  7. Characterization of an evaporating direct-injected gasoline spray using laser-induced exciplex fluorescence and particle image velocimetry techniques

    Energy Technology Data Exchange (ETDEWEB)

    Dong-Seok Choi; Choongsik Bae [Korea Advanced Institute of Science and Technology, Taejon (Korea). Dept. of Mechanical Engineering; Duck-Jool Kim [Pusan National University (Korea). School of Mechanical Engineering

    2004-07-01

    The purpose of this study is to characterize an evaporating direct-injected (DI) gasoline spray from a high-pressure swirl injector using the laser-induced exciplex fluorescence (LIEF) technique and particle image velocimetry (PIV). A fluorobenzene/diethylmethylamine (DEMA) system was used as the exciplex-forming dopants. The behaviour of the liquid and vapour phases was analysed by image processing. For the analysis of vorticity inside the spray, droplet velocity data obtained by PIV were used. The experiments were performed at two ambient temperatures (293 and 473 K) and three different ambient pressures (0.1, 0.5 and 1.0 MPa). It was found that ambient temperature had a significant effect on the axial and radial growth of the liquid phase of the evaporating spray at atmospheric pressure while it had little effect under elevated pressures. Radial growth of the vapour phase of the evaporating spray was more dominant than axial growth under high temperature and pressure conditions. As the ambient pressure was elevated, the liquid phase of the spray transformed from a hollow cone to a solid cone of bell shape, while the vapour phase varied from a widespread distribution to a compact shape with a locally richer mixture. The evaporating spray could be divided into two spray regions from the analysis of vorticity and the distributions of liquid and vapour phases. The cone region (penetrations of 0.3-0.5) was mainly liquid phase and disappeared rapidly at the end of injection. The mixing region contained the active interaction between entrained air and fuel vapour. (author)

  8. Multilinear analysis of Time-Resolved Laser-Induced Fluorescence Spectra of U(VI) containing natural water samples

    Science.gov (United States)

    Višňák, Jakub; Steudtner, Robin; Kassahun, Andrea; Hoth, Nils

    2017-09-01

    Natural waters' uranium level monitoring is of great importance for health and environmental protection. One possible detection method is the Time-Resolved Laser-Induced Fluorescence Spectroscopy (TRLFS), which offers the possibility to distinguish different uranium species. The analytical identification of aqueous uranium species in natural water samples is of distinct importance since individual species differ significantly in sorption properties and mobility in the environment. Samples originate from former uranium mine sites and have been provided by Wismut GmbH, Germany. They have been characterized by total elemental concentrations and TRLFS spectra. Uranium in the samples is supposed to be in form of uranyl(VI) complexes mostly with carbonate (CO32- ) and bicarbonate (HCO3- ) and to lesser extend with sulphate (SO42- ), arsenate (AsO43- ), hydroxo (OH- ), nitrate (NO3- ) and other ligands. Presence of alkaline earth metal dications (M = Ca2+ , Mg2+ , Sr2+ ) will cause most of uranyl to prefer ternary complex species, e.g. Mn(UO2)(CO3)32n-4 (n ɛ {1; 2}). From species quenching the luminescence, Cl- and Fe2+ should be mentioned. Measurement has been done under cryogenic conditions to increase the luminescence signal. Data analysis has been based on Singular Value Decomposition and monoexponential fit of corresponding loadings (for separate TRLFS spectra, the "Factor analysis of Time Series" (FATS) method) and Parallel Factor Analysis (PARAFAC, all data analysed simultaneously). From individual component spectra, excitation energies T00, uranyl symmetric mode vibrational frequencies ωgs and excitation driven U-Oyl bond elongation ΔR have been determined and compared with quasirelativistic (TD)DFT/B3LYP theoretical predictions to cross -check experimental data interpretation. Note to the reader: Several errors have been produced in the initial version of this article. This new version published on 23 October 2017 contains all the corrections.

  9. Laser-induced interactions

    International Nuclear Information System (INIS)

    Green, W.R.

    1979-01-01

    This dissertation discusses some of the new ways that lasers can be used to control the energy flow in a medium. Experimental and theoretical considerations of the laser-induced collision are discussed. The laser-induced collision is a process in which a laser is used to selectively transfer energy from a state in one atomic or molecular species to another state in a different species. The first experimental demonstration of this process is described, along with later experiments in which lasers were used to create collisional cross sections as large as 10 - 13 cm 2 . Laser-induced collisions utilizing both a dipole-dipole interaction and dipole-quadrupole interaction have been experimentally demonstrated. The theoretical aspects of other related processes such as laser-induced spin-exchange, collision induced Raman emission, and laser-induced charge transfer are discussed. Experimental systems that could be used to demonstrate these various processes are presented. An experiment which produced an inversion of the resonance line of an ion by optical pumping of the neutral atom is described. This type of scheme has been proposed as a possible method for constructing VUV and x-ray lasers

  10. The influence of PAH concentration and distribution on real-time in situ measurements of petroleum products in soils using laser induced fluorescence

    International Nuclear Information System (INIS)

    Douglas, G.S.; Lieberman, S.H.; McGinnis, W.C.; Knowles, D.; Peven, C.

    1995-01-01

    Real-time laser induced fluorescence (LIF) in situ measurements of soil samples provide a reliable and cost-effective screening tool for hydrocarbon site assessments. The site characterization and analysis penetrometer system (SCAPS), is a truck-mounted cone penetrometer probe modified with a sapphire window and connected to a laser by fiber optics. The pulsed nitrogen laser 337-nm excitation source induces fluorescence in polynuclear aromatic hydrocarbons (PAHs), which are present in petroleum products. The fluorescence response of these compounds is measured with a fluorometer. The SCAPS can provide continuous hydrocarbon screening measurements to soil depths greater than 100 feet. Discrete soil samples collected from the SCAPS boreholes were extracted and analyzed for total petroleum hydrocarbons (TPH), by gas chromatography with flame ionization detection (GC/FID), and 16 parent and over 100 alkyl substituted PAH compounds by gas chromatography with mass spectrometry detection (GC/MS). This method provides a basis for evaluating the relationship between TPH and PAH concentrations in the soil samples and laser induced fluorescence measurements from the soil borings

  11. Nitric oxide density measurements in air and air/fuel nanosecond pulse discharges by laser induced fluorescence

    International Nuclear Information System (INIS)

    Uddi, M; Jiang, N; Adamovich, I V; Lempert, W R

    2009-01-01

    Laser induced fluorescence is used to measure absolute nitric oxide concentrations in air, methane-air and ethylene-air non-equilibrium plasmas, as a function of time after initiation of a single pulse, 20 kV peak voltage, 25 ns pulse duration discharge. A mixture of NO and nitrogen with known composition (4.18 ppm NO) is used for calibration. Peak NO density in air at 60 Torr, after a single pulse, is ∼8 x 10 12 cm -3 (∼4.14 ppm) occurring at ∼250 μs after the pulse, with decay time of ∼16.5 ms. Peak NO atom mole fraction in a methane-air mixture with equivalence ratio of ψ = 0.5 is found to be approximately equal to that in air, with approximately the same rise and decay rate. In an ethylene-air mixture (also with equivalence ratio of ψ = 0.5), the rise and decay times are comparable to air and methane-air, but the peak NO concentration is reduced by a factor of approximately 2.5. Spontaneous emission measurements show that excited electronic states N 2 (C 3 Π) and NO(A 2 Σ) in air at P = 60 Torr decay within ∼20 ns and ∼1 μs, respectively. Kinetic modelling calculations incorporating air plasma kinetics complemented with the GRI Mech 3.0 hydrocarbon oxidation mechanism are compared with the experimental data using three different NO production mechanisms. It is found that NO concentration rise after the discharge pulse is much faster than predicted by Zel'dovich mechanism reactions, by two orders of magnitude, but much slower compared with reactions of electronically excited nitrogen atoms and molecules, also by two orders of magnitude. It is concluded that processes involving long lifetime (∼100 μs) metastable states, such as N 2 (X 1 Σ,v) and O 2 (b 1 Σ), formed by quenching of the metastable N 2 (A 3 Σ) state by ground electronic state O 2 , may play a dominant role in NO formation. NO decay, in all cases, is found to be dominated by the reverse Zel'dovich reaction, NO + O → N + O 2 , as well as by conversion into NO 2 in a reaction

  12. Nitric oxide density measurements in air and air/fuel nanosecond pulse discharges by laser induced fluorescence

    Science.gov (United States)

    Uddi, M.; Jiang, N.; Adamovich, I. V.; Lempert, W. R.

    2009-04-01

    Laser induced fluorescence is used to measure absolute nitric oxide concentrations in air, methane-air and ethylene-air non-equilibrium plasmas, as a function of time after initiation of a single pulse, 20 kV peak voltage, 25 ns pulse duration discharge. A mixture of NO and nitrogen with known composition (4.18 ppm NO) is used for calibration. Peak NO density in air at 60 Torr, after a single pulse, is ~8 × 1012 cm-3 (~4.14 ppm) occurring at ~250 µs after the pulse, with decay time of ~16.5 ms. Peak NO atom mole fraction in a methane-air mixture with equivalence ratio of phiv = 0.5 is found to be approximately equal to that in air, with approximately the same rise and decay rate. In an ethylene-air mixture (also with equivalence ratio of phiv = 0.5), the rise and decay times are comparable to air and methane-air, but the peak NO concentration is reduced by a factor of approximately 2.5. Spontaneous emission measurements show that excited electronic states N2(C 3Π) and NO(A 2Σ) in air at P = 60 Torr decay within ~20 ns and ~1 µs, respectively. Kinetic modelling calculations incorporating air plasma kinetics complemented with the GRI Mech 3.0 hydrocarbon oxidation mechanism are compared with the experimental data using three different NO production mechanisms. It is found that NO concentration rise after the discharge pulse is much faster than predicted by Zel'dovich mechanism reactions, by two orders of magnitude, but much slower compared with reactions of electronically excited nitrogen atoms and molecules, also by two orders of magnitude. It is concluded that processes involving long lifetime (~100 µs) metastable states, such as N2(X 1Σ,v) and O2(b 1Σ), formed by quenching of the metastable N2(A 3Σ) state by ground electronic state O2, may play a dominant role in NO formation. NO decay, in all cases, is found to be dominated by the reverse Zel'dovich reaction, NO + O → N + O2, as well as by conversion into NO2 in a reaction of NO with ozone.

  13. Temporal evolution of the spectral lines emission and temperatures in laser induced plasmas through characteristic parameters

    International Nuclear Information System (INIS)

    Bredice, F.; Pacheco Martinez, P.; Sánchez-Aké, C.; Villagrán-Muniz, M.

    2015-01-01

    In this work, we propose an extended Boltzmann plot method to determine the usefulness of spectral lines for plasma parameter calculations. Based on the assumption that transient plasmas are under ideal conditions during an specific interval of time Δt, (i.e. thin, homogeneous and in local thermodynamic equilibrium (LTE)), the associated Boltzmann plots describe a surface in the space defined by the coordinates X = Energy, Y = Time and Z = ln (λ jl I j /g j A jl ), where I j is the integrated intensity of the spectral line, g j is the statistical weight of the level j, λ jl is the wavelength of the considered line and A jl is its transition rate. In order to express the Boltzmann plot surface in terms of a reduced set of constants B i , and δ i , we developed as a power series of time, the logarithm of I n (t)/I n (t 0 ), where I n (t) is the integrated intensity of any spectral line at time t, and I n (t 0 ) at initial time. Moreover, the temporal evolution of the intensity of any spectral line and consequently the temperature of the plasma can be also expressed with these constants. The comparison of the temporal evolution of the line intensity calculated using these constants with their experimental values, can be used as a criterion for selecting useful lines in plasma analysis. Furthermore, this method can also be applied to determine self-absorption or enhancement of the spectral lines, to evaluate a possible departure of LTE, and to check or estimate the upper level energy value of any spectral line. An advantage of this method is that the value of these constants does not depend on the spectral response of the detection system, the uncertainty of the transition rates belonging to the analyzed spectral lines or any other time-independent parameters. In order to prove our method, we determined the constants B i and δ i and therefore the Boltzmann plot surface from the temporal evolution of carbon lines obtained from a plasma generated by a Nd:YAG laser

  14. Temporal evolution of the spectral lines emission and temperatures in laser induced plasmas through characteristic parameters

    Energy Technology Data Exchange (ETDEWEB)

    Bredice, F., E-mail: faustob@ciop.unlp.edu.ar [Centro de Investigaciones Ópticas, P.O. Box 3 C. P.1897 Gonnet, La Plata (Argentina); Pacheco Martinez, P. [Grupo de Espectroscopía Óptica de Emisión y Láser, Universidad del Atlántico, Barranquilla (Colombia); Sánchez-Aké, C.; Villagrán-Muniz, M. [Laboratorio de Fotofísica, Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Apartado Postal 70-186, México D.F. 04510 (Mexico)

    2015-05-01

    In this work, we propose an extended Boltzmann plot method to determine the usefulness of spectral lines for plasma parameter calculations. Based on the assumption that transient plasmas are under ideal conditions during an specific interval of time Δt, (i.e. thin, homogeneous and in local thermodynamic equilibrium (LTE)), the associated Boltzmann plots describe a surface in the space defined by the coordinates X = Energy, Y = Time and Z = ln (λ{sub jl}I{sub j}/g{sub j}A{sub jl}), where I{sub j} is the integrated intensity of the spectral line, g{sub j} is the statistical weight of the level j, λ{sub jl} is the wavelength of the considered line and A{sub jl} is its transition rate. In order to express the Boltzmann plot surface in terms of a reduced set of constants B{sub i}, and δ{sub i}, we developed as a power series of time, the logarithm of I{sub n}(t)/I{sub n}(t{sub 0}), where I{sub n}(t) is the integrated intensity of any spectral line at time t, and I{sub n}(t{sub 0}) at initial time. Moreover, the temporal evolution of the intensity of any spectral line and consequently the temperature of the plasma can be also expressed with these constants. The comparison of the temporal evolution of the line intensity calculated using these constants with their experimental values, can be used as a criterion for selecting useful lines in plasma analysis. Furthermore, this method can also be applied to determine self-absorption or enhancement of the spectral lines, to evaluate a possible departure of LTE, and to check or estimate the upper level energy value of any spectral line. An advantage of this method is that the value of these constants does not depend on the spectral response of the detection system, the uncertainty of the transition rates belonging to the analyzed spectral lines or any other time-independent parameters. In order to prove our method, we determined the constants B{sub i} and δ{sub i} and therefore the Boltzmann plot surface from the temporal

  15. Laser induced fluorescence and phosphorescence of matrix isolated glyoxal - Evidence for exciplex formation in the A 1Au and a 3Au states

    Science.gov (United States)

    Van Ijzendoorn, L. J.; Baas, F.; Koernig, S.; Greenberg, J. M.; Allamandola, L. J.

    1986-01-01

    Laser-induced fluorescence and phosphorescence as well as infrared and visible absorption spectra of glyoxal in Ar, N2, and CO matrices are presented and analyzed. Glyoxal in its first excited electronic state is shown to form an exciplex with its nearest neighbors in all three matrices, and transitions normally forbidden dominate the emission spectra. The spectral characteristics of these complexes are similar to those of the Ar-glyoxal complex found in supersonic beam experiments. Due to the matrix cage effect, no vibrational predissociation is observed. The phosphorescence lifetime is determined and an upper limit is given for the fluorescence lifetime. This, in combination with the relative intensities of fluorescence and phosphorescence, can be used to place limits on the quantum yields of the various relaxation processes.

  16. Selection of an analytical line for determining lithium in aluminum alloys by laser induced breakdown spectrometry

    International Nuclear Information System (INIS)

    Lednev, V.N.; Yakovlev, A.V.; Labutin, T.A.; Popov, A.M.; Zorov, N.B.

    2007-01-01

    Possibilities for determining lithium in aluminum alloys by laser spark spectrometry are studied. The optimum conditions for registering the emission signal of lithium at which the effect of the continuous background radiation of the laser plasma attains a minimum are found. The possibility of determining lithium by laser spark spectrometry using the spectral line at 610 nm is studied for the first time. A comparison of the detection limits and sensitivities of determining lithium by emission its lines at 610 and 671 nm has indicated the advisability of using the line 610 nm for the studied alloys. The detection limit calculated using the 3σ test was found to be 230 ppm (610 nm) and 870 ppm (671 nm) [ru

  17. Remote quantitative analysis of minerals based on multispectral line-calibrated laser-induced breakdown spectroscopy (LIBS).

    Science.gov (United States)

    Wan, Xiong; Wang, Peng

    2014-01-01

    Laser-induced breakdown spectroscopy (LIBS) is a feasible remote sensing technique used for mineral analysis in some unapproachable places where in situ probing is needed, such as analysis of radioactive elements in a nuclear leak or the detection of elemental compositions and contents of minerals on planetary and lunar surfaces. Here a compact custom 15 m focus optical component, combining a six times beam expander with a telescope, has been built, with which the laser beam of a 1064 nm Nd ; YAG laser is focused on remote minerals. The excited LIBS signals that reveal the elemental compositions of minerals are collected by another compact single lens-based signal acquisition system. In our remote LIBS investigations, the LIBS spectra of an unknown ore have been detected, from which the metal compositions are obtained. In addition, a multi-spectral line calibration (MSLC) method is proposed for the quantitative analysis of elements. The feasibility of the MSLC and its superiority over a single-wavelength determination have been confirmed by comparison with traditional chemical analysis of the copper content in the ore.

  18. Microfluidic setup for on-line SERS monitoring using laser induced nanoparticle spots as SERS active substrate

    Directory of Open Access Journals (Sweden)

    Oana-M. Buja

    2017-01-01

    Full Text Available A microfluidic setup which enables on-line monitoring of residues of malachite green (MG using surface-enhanced Raman scattering (SERS is reported. The SERS active substrate was prepared via laser induced synthesis of silver or gold nanoparticles spot on the bottom of a 200 μm inner dimension glass capillary, by focusing the laser beam during a continuous flow of a mixture of silver nitrate or gold chloride and sodium citrate. The described microfluidic setup enables within a few minutes the monitoring of several processes: the synthesis of the SERS active spot, MG adsorption to the metal surface, detection of the analyte when saturation of the SERS signal is reached, and finally, the desorption of MG from the spot. Moreover, after MG complete desorption, the regeneration of the SERS active spot was achieved. The detection of MG was possible down to 10−7 M concentration with a good reproducibility when using silver or gold spots as SERS substrate.

  19. Diagnosis of lubricating oil by evaluating cyanide and carbon molecular emission lines in laser induced breakdown spectra

    Science.gov (United States)

    Elnasharty, I. Y.; Kassem, A. K.; Sabsabi, M.; Harith, M. A.

    2011-08-01

    To prevent engine failure it is essential to change lubricating oil regularly before it loses its protective properties. It is also necessary to monitor the physical and chemical conditions of the oil to reliably determine the optimum oil-change intervals. The present work focuses on studying evolution of the cyanide (CN) and carbon (C 2) molecular spectral emission lines in the laser induced breakdown spectra of lubricating oil as a function of its consumption. The intensities of these molecular bands have been taken as indicator of engine oil degradation at certain mileage. Furthermore, the percentage of decay of CN and C 2 integral intensity values at the corresponding mileage was calculated in order to relate it to the degree of consumption of the motor oil. Such percentage decay of the CN and C 2 integral intensities have been found to increase gradually with increasing mileage which is accompanied with increasing depletion of engine oil. The results of using LIBS technique in the present measurements proved that it is possible to have a direct, straightforward and easy method for prediction of lubricating oil degree of consumption. This may facilitate scheduling the proper time and/or mileage intervals for changing the oil to avoid any possibility of engine failure.

  20. Diagnosis of lubricating oil by evaluating cyanide and carbon molecular emission lines in laser induced breakdown spectra

    Energy Technology Data Exchange (ETDEWEB)

    Elnasharty, I.Y.; Kassem, A.K. [National Institute of Laser Enhanced Science, Cairo University (Egypt); Sabsabi, M. [National Research Council, Industrial Material Institute, Quebec (Canada); Harith, M.A., E-mail: mharithm@niles.edu.eg [National Institute of Laser Enhanced Science, Cairo University (Egypt)

    2011-08-15

    To prevent engine failure it is essential to change lubricating oil regularly before it loses its protective properties. It is also necessary to monitor the physical and chemical conditions of the oil to reliably determine the optimum oil-change intervals. The present work focuses on studying evolution of the cyanide (CN) and carbon (C{sub 2}) molecular spectral emission lines in the laser induced breakdown spectra of lubricating oil as a function of its consumption. The intensities of these molecular bands have been taken as indicator of engine oil degradation at certain mileage. Furthermore, the percentage of decay of CN and C{sub 2} integral intensity values at the corresponding mileage was calculated in order to relate it to the degree of consumption of the motor oil. Such percentage decay of the CN and C{sub 2} integral intensities have been found to increase gradually with increasing mileage which is accompanied with increasing depletion of engine oil. The results of using LIBS technique in the present measurements proved that it is possible to have a direct, straightforward and easy method for prediction of lubricating oil degree of consumption. This may facilitate scheduling the proper time and/or mileage intervals for changing the oil to avoid any possibility of engine failure.

  1. Diagnosis of lubricating oil by evaluating cyanide and carbon molecular emission lines in laser induced breakdown spectra

    International Nuclear Information System (INIS)

    Elnasharty, I.Y.; Kassem, A.K.; Sabsabi, M.; Harith, M.A.

    2011-01-01

    To prevent engine failure it is essential to change lubricating oil regularly before it loses its protective properties. It is also necessary to monitor the physical and chemical conditions of the oil to reliably determine the optimum oil-change intervals. The present work focuses on studying evolution of the cyanide (CN) and carbon (C 2 ) molecular spectral emission lines in the laser induced breakdown spectra of lubricating oil as a function of its consumption. The intensities of these molecular bands have been taken as indicator of engine oil degradation at certain mileage. Furthermore, the percentage of decay of CN and C 2 integral intensity values at the corresponding mileage was calculated in order to relate it to the degree of consumption of the motor oil. Such percentage decay of the CN and C 2 integral intensities have been found to increase gradually with increasing mileage which is accompanied with increasing depletion of engine oil. The results of using LIBS technique in the present measurements proved that it is possible to have a direct, straightforward and easy method for prediction of lubricating oil degree of consumption. This may facilitate scheduling the proper time and/or mileage intervals for changing the oil to avoid any possibility of engine failure.

  2. The development and deployment of a ground-based, laser-induced fluorescence instrument for the in situ detection of iodine monoxide radicals

    Energy Technology Data Exchange (ETDEWEB)

    Thurlow, M. E., E-mail: thurlow@huarp.harvard.edu; Hannun, R. A.; Lapson, L. B.; Anderson, J. G. [Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138 (United States); Co, D. T. [Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138 (United States); Argonne-Northwestern Solar Energy Research Center and Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113 (United States); O' Brien, A. S. [Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138 (United States); Department of Civil and Environmental Engineering, Princeton University, Princeton, New Jersey 08544 (United States); Hanisco, T. F. [Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138 (United States); NASA Goddard Space Flight Center, Code 614, Greenbelt, Maryland 20771 (United States)

    2014-04-15

    High abundances of iodine monoxide (IO) are known to exist and to participate in local photochemistry of the marine boundary layer. Of particular interest are the roles IO plays in the formation of new particles in coastal marine environments and in depletion episodes of ozone and mercury in the Arctic polar spring. This paper describes a ground-based instrument that measures IO at mixing ratios less than one part in 10{sup 12}. The IO radical is measured by detecting laser-induced fluorescence at wavelengths longer that 500 nm. Tunable visible light is used to pump the A{sup 2}Π{sub 3/2} (v{sup ′} = 2) ← X{sup 2}Π{sub 3/2} (v{sup ″} = 0) transition of IO near 445 nm. The laser light is produced by a solid-state, Nd:YAG-pumped Ti:Sapphire laser at 5 kHz repetition rate. The laser-induced fluorescence instrument performs reliably with very high signal-to-noise ratios (>10) achieved in short integration times (<1 min). The observations from a validation deployment to the Shoals Marine Lab on Appledore Island, ME are presented and are broadly consistent with in situ observations from European Coastal Sites. Mixing ratios ranged from the instrumental detection limit (<1 pptv) to 10 pptv. These data represent the first in situ point measurements of IO in North America.

  3. Laser induced fluorescence lifetime characterization of Bacillus endospore species using time correlated single photon counting analysis with the multi-exponential fit method

    Science.gov (United States)

    Smith, Clint; Edwards, Jarrod; Fisher, Andmorgan

    2010-04-01

    Rapid detection of biological material is critical for determining presence/absence of bacterial endospores within various investigative programs. Even more critical is that if select material tests positive for bacillus endospores then tests should provide data at the species level. Optical detection of microbial endospore formers such as Bacillus sp. can be heavy, cumbersome, and may only identify at the genus level. Data provided from this study will aid in characterization needed by future detection systems for further rapid breakdown analysis to gain insight into a more positive signature collection of Bacillus sp. Literature has shown that fluorescence spectroscopy of endospores could be statistically separated from other vegetative genera, but could not be separated among one another. Results of this study showed endospore species separation is possible using laser-induce fluorescence with lifetime decay analysis for Bacillus endospores. Lifetime decays of B. subtilis, B. megaterium, B. coagulans, and B. anthracis Sterne strain were investigated. Using the Multi-Exponential fit method data showed three distinct lifetimes for each species within the following ranges, 0.2-1.3 ns; 2.5-7.0 ns; 7.5-15.0 ns, when laser induced at 307 nm. The four endospore species were individually separated using principle component analysis (95% CI).

  4. The development and deployment of a ground-based, laser-induced fluorescence instrument for the in situ detection of iodine monoxide radicals

    International Nuclear Information System (INIS)

    Thurlow, M. E.; Hannun, R. A.; Lapson, L. B.; Anderson, J. G.; Co, D. T.; O'Brien, A. S.; Hanisco, T. F.

    2014-01-01

    High abundances of iodine monoxide (IO) are known to exist and to participate in local photochemistry of the marine boundary layer. Of particular interest are the roles IO plays in the formation of new particles in coastal marine environments and in depletion episodes of ozone and mercury in the Arctic polar spring. This paper describes a ground-based instrument that measures IO at mixing ratios less than one part in 10 12 . The IO radical is measured by detecting laser-induced fluorescence at wavelengths longer that 500 nm. Tunable visible light is used to pump the A 2 Π 3/2 (v ′ = 2) ← X 2 Π 3/2 (v ″ = 0) transition of IO near 445 nm. The laser light is produced by a solid-state, Nd:YAG-pumped Ti:Sapphire laser at 5 kHz repetition rate. The laser-induced fluorescence instrument performs reliably with very high signal-to-noise ratios (>10) achieved in short integration times (<1 min). The observations from a validation deployment to the Shoals Marine Lab on Appledore Island, ME are presented and are broadly consistent with in situ observations from European Coastal Sites. Mixing ratios ranged from the instrumental detection limit (<1 pptv) to 10 pptv. These data represent the first in situ point measurements of IO in North America

  5. The Development and Deployment of a Ground-Based, Laser-Induced Fluorescence Instrument for the In Situ Detection of Iodine Monoxide Radicals

    Science.gov (United States)

    Thurlow, M. E.; Co, D. T.; O'Brien, A. S.; Hannun, R. A.; Lapson, L. B.; Hanisco, T. F.; Anderson, J. G.

    2014-01-01

    High abundances of iodine monoxide (IO) are known to exist and to participate in local photochemistry of the marine boundary layer. Of particular interest are the roles IO plays in the formation of new particles in coastal marine environments and in depletion episodes of ozone and mercury in the Arctic polar spring. This paper describes a ground-based instrument that measures IO at mixing ratios less than one part in 1012. The IO radical is measured by detecting laser-induced fluorescence at wavelengths longer that 500 nm. Tunable visible light is used to pump the A23/2 (v = 2) ? X23/2 (v = 0) transition of IO near 445 nm. The laser light is produced by a solid-state, Nd:YAG-pumped Ti:Sapphire laser at 5 kHz repetition rate. The laser-induced fluorescence instrument performs reliably with very high signal-to-noise ratios (>10) achieved in short integration times (<1 min). The observations from a validation deployment to the Shoals Marine Lab on Appledore Island, ME are presented and are broadly consistent with in situ observations from European Coastal Sites. Mixing ratios ranged from the instrumental detection limit (<1 pptv) to 10 pptv. These data represent the first in situ point measurements of IO in North America.

  6. Study the effect of insecticide dimethoate on photosynthetic pigments and photosynthetic activity of pigeon pea: Laser-induced chlorophyll fluorescence spectroscopy.

    Science.gov (United States)

    Pandey, Jitendra Kumar; Dubey, Gunjan; Gopal, R

    2015-10-01

    Pigeon pea is one of the most important legume crops in India and dimethoate is a widely used insecticide in various crop plants. We studied the effect of dimethoate on growth and photosynthetic activity of pigeon pea plants over a short and long term exposure. Plant growth parameters, photosynthetic pigment content and chlorophyll fluorescence response of pigeon pea (Cajanus cajan L.) plants treated with various concentrations of the insecticide dimethoate (10, 20, 40 and 80 ppm) have been compared for 30 days at regular intervals of 10 days each. Laser induced chlorophyll fluorescence spectra and fluorescence-induction kinetics (FIK) curve of dimethoate treated pigeon pea plants were recorded after 10, 20 and 30 days of treatment. Fluorescence intensity ratio at the two fluorescence maxima (F685/F730) was calculated by evaluating curve-fitted parameters. The variable chlorophyll fluorescence decrease ratio (Rfd) was determined from the FIK curves. Our study revealed that after 10 days of treatment, 10 ppm of dimethoate showed stimulatory response whereas 20, 40 and 80 ppm of dimethoate showed inhibitory response for growth and photosynthetic activity of pigeon pea plants, but after 20 and 30 days of treatment all the tested concentrations of dimethoate became inhibitory. This study clearly shows that dimethoate is highly toxic to the pigeon pea plant, even at very low concentration (10 ppm), if used for a prolonged duration. Our study may thus be helpful in determining the optimal dose of dimethoate in agricultural practices. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. High-Throughput Analysis With 96-Capillary Array Electrophoresis and Integrated Sample Preparation for DNA Sequencing Based on Laser Induced Fluorescence Detection

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Gang [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    The purpose of this research was to improve the fluorescence detection for the multiplexed capillary array electrophoresis, extend its use beyond the genomic analysis, and to develop an integrated micro-sample preparation system for high-throughput DNA sequencing. The authors first demonstrated multiplexed capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) separations in a 96-capillary array system with laser-induced fluorescence detection. Migration times of four kinds of fluoresceins and six polyaromatic hydrocarbons (PAHs) are normalized to one of the capillaries using two internal standards. The relative standard deviations (RSD) after normalization are 0.6-1.4% for the fluoresceins and 0.1-1.5% for the PAHs. Quantitative calibration of the separations based on peak areas is also performed, again with substantial improvement over the raw data. This opens up the possibility of performing massively parallel separations for high-throughput chemical analysis for process monitoring, combinatorial synthesis, and clinical diagnosis. The authors further improved the fluorescence detection by step laser scanning. A computer-controlled galvanometer scanner is adapted for scanning a focused laser beam across a 96-capillary array for laser-induced fluorescence detection. The signal at a single photomultiplier tube is temporally sorted to distinguish among the capillaries. The limit of detection for fluorescein is 3 x 10-11 M (S/N = 3) for 5-mW of total laser power scanned at 4 Hz. The observed cross-talk among capillaries is 0.2%. Advantages include the efficient utilization of light due to the high duty-cycle of step scan, good detection performance due to the reduction of stray light, ruggedness due to the small mass of the galvanometer mirror, low cost due to the simplicity of components, and flexibility due to the independent paths for excitation and emission.

  8. Identification of the pigment responsible for the blue fluorescence band in the laser induced fluorescence (LIF) spectra of green plants, and the potential use of this band in remotely estimating rates of photosynthesis

    International Nuclear Information System (INIS)

    Chappelle, E.W.; McMurtrey, J.E. III; Kim, M.S.

    1991-01-01

    The laser-induced fluorescence (LIF) of vegetation is being investigated in this laboratory for use as a technique for the remote detection of the effects of environmental stress upon vegetation, as well as for plant identification. The fluorescence band with a maximum at 440 nm, in conjunction with the chlorophyll bands with maxima at 685 and 740 nm, has been found to be a critical band in the development of algorithms for detecting stress, and identifying plant types. The identification of the plant constituent responsible for this band is vital to understanding the mechanism underlying its fluorescence changes in response to environmental and physiological changes. The identification was achieved as follows: The laser induced fluorescence (LIF) spectra of pure plant pigments were determined. Fluorescence bands with maxima at 420 nm, 440 nm, 490 nm, and 525 nm were observed for vitamin K 1 , reduced nicotinamide adenine dinucleotide (NADPH), beta-carotene, and riboflavin, respectively. The LIF spectra of water extracts and acetone extracts of clover leaves were also measured. It was found that the blue fluorescence band was associated with the water extract. NADPH which is a water-soluble compound, and the water extract of clover had no fluorescence after oxidation by potassium ferricyanide, while the fluorescence of water insoluble vitamin K 1 was unchanged by the oxidizing agent. It was also found that the absorption maximum of NADPH was the same as the absorption maximum of the aqueous extract of clover. The above findings indicated that the compound responsible for the blue fluorescence at 440 nm is in the reduced state and is water-soluble. It was concluded that NADPH was responsible for the blue fluorescence at 440 nm. The strong linear relationship between the fluorescence at 440 nm and the rate of photosynthesis suggests the possible use of LIF measurements in the remote estimation of photosynthetic rates. (author)

  9. Evaluation of Optical Depths and Self-Absorption of Strontium and Aluminum Emission Lines in Laser-Induced Breakdown Spectroscopy (LIBS).

    Science.gov (United States)

    Alfarraj, Bader A; Bhatt, Chet R; Yueh, Fang Yu; Singh, Jagdish P

    2017-04-01

    Laser-induced breakdown spectroscopy (LIBS) is a widely used laser spectroscopic technique in various fields, such as material science, forensic science, biological science, and the chemical and pharmaceutical industries. In most LIBS work, the analysis is performed using radiative transitions from atomic emissions. In this study, the plasma temperature and the product [Formula: see text] (the number density N and the absorption path length [Formula: see text]) were determined to evaluate the optical depths and the self-absorption of Sr and Al lines. A binary mixture of strontium nitrate and aluminum oxide was used as a sample, consisting of variety of different concentrations in powder form. Laser-induced breakdown spectroscopy spectra were collected by varying various parameters, such as laser energy, gate delay time, and gate width time to optimize the LIBS signals. Atomic emission from Sr and Al lines, as observed in the LIBS spectra of different sample compositions, was used to characterize the laser induced plasma and evaluate the optical depths and self-absorption of LIBS.

  10. On the use of time-resolved laser-induced fluorescence (TRLIF) and electrospray mass spectrometry (ES-MS) for speciation studies

    International Nuclear Information System (INIS)

    Moulin, C.

    2003-01-01

    Time-resolved laser induced fluorescence (TRLIF) and electrospray mass spectrometry (ES-MS) are used for speciation studies. While the former has been used for long time, the latter is rather new in the field of speciation. These two techniques have different advantages such as sensitivity (especially for TRLIF), selectivity and multielement capabilities (in case of ES-MS). Examples obtained from studies carried out within the CEA are presented. Concerning TRLIF, emphasis is put on uranyl ion speciation in nitric acid to phosphoric acid going through hydroxo complexes. Concerning ES-MS, humic substances identification as well as speciation of cesium, zirconium, thorium and uranyl ions in various complexing media are presented. Comparisons of TRLIF and ES-MS results are made in the case of uranyl hydroxo complexes and favourably compared with OECD data. Trends for these two techniques are also discussed. (orig.)

  11. Detection of gain enhancement in laser-induced fluorescence of rhodamine B lasing dye by silicon dioxide nanostructures-coated cavity

    Science.gov (United States)

    Al-Tameemi, Mohammed N. A.

    2018-03-01

    In this work, nanostructured silicon dioxide films are deposited by closed-field unbalanced direct-current (DC) reactive magnetron sputtering technique on two sides of quartz cells containing rhodamine B dye dissolved in ethanol with 10‒5 M concentration as a random gain medium. The preparation conditions are optimized to prepare highly pure SiO2 nanostructures with a minimum particle size of about 20 nm. The effect of SiO2 films as external cavity for the random gain medium is determined by the laser-induced fluorescence of this medium, and an increase of about 200% in intensity is observed after the deposition of nanostructured SiO2 thin films on two sides of the dye cell.

  12. Measurement of OH free radical in magnetized sheet plasma crossed with vertical gas-flow by laser-induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Tonegawa, Akira; Takatori, Masahiko; Kobayashi, Yukihiro; Kawamura, Kazutaka; Takayama, Kazuo

    1997-01-01

    We demonstrated the production of OH free radicals in an argon magnetized sheet plasma crossed with vertical gas-flow mixed with an oxygen gas O 2 and a hydrogen gas H 2 . The density and the rotational-vibrational temperature of the OH free radicals were measured by a laser-induced fluorescence (LIF). The density of OH free radicals increases with increasing O 2 gas-flow, while the high energy part of the electron-energy-distribution-function f e (E) above 8 eV decreases. These results suggest the high energy part of f e (E) is contributed to the dissociation of O 2 and the production of OH free radicals. (author)

  13. 4D Density Determination of NH Radicals in an MSE Microplasma Combining Planar Laser Induced Fluorescence and Cavity Ring-Down Spectroscopy

    Science.gov (United States)

    Visser, Martin; Schenk, Andreas; Gericke, Karl-Heinz

    2010-10-01

    An application of microplasmas is surface modification under mild conditions and of small, well defined areas. For this, an understanding of the plasma composition is of importance. First results of our work on the production and detection of NH radicals in a capacitively coupled radio frequency (RF) microplasma are presented. A microstructured comb electrode was used to generate a glow discharge in a hydrogen/nitrogen gas mixture by applying 13.56 MHz RF voltage. The techniques of planar laser induced fluorescence (PLIF) and cavity ring-down spectroscopy (CRDS) are used for space and time resolved, quantitative detection of the NH radical in the plasma. The rotational temperature was determined to be 820 K and, the density 5.1×1012 cm3. Also, time dependent behaviour of the NH production was observed.

  14. 4D Density Determination of NH Radicals in an MSE Microplasma Combining Planar Laser Induced Fluorescence and Cavity Ring-Down Spectroscopy

    International Nuclear Information System (INIS)

    Visser, Martin; Schenk, Andreas; Gericke, Karl-Heinz

    2010-01-01

    An application of microplasmas is surface modification under mild conditions and of small, well defined areas. For this, an understanding of the plasma composition is of importance. First results of our work on the production and detection of NH radicals in a capacitively coupled radio frequency (RF) microplasma are presented. A microstructured comb electrode was used to generate a glow discharge in a hydrogen/nitrogen gas mixture by applying 13.56 MHz RF voltage. The techniques of planar laser induced fluorescence (PLIF) and cavity ring-down spectroscopy (CRDS) are used for space and time resolved, quantitative detection of the NH radical in the plasma. The rotational temperature was determined to be 820 K and, the density 5.1x10 12 cm 3 . Also, time dependent behaviour of the NH production was observed.

  15. Time resolved laser induced fluorescence on argon intermediate pressure microwave discharges : measuring the depopulation rates of the 4p and 5p excited levels as induced by electron and atom collisions

    NARCIS (Netherlands)

    Palomares Linares, J.M.; Graef, W.A.A.D.; Hubner, S.; Mullen, van der J.J.A.M.

    2013-01-01

    The reaction kinetics in the excitation space of Ar is explored by means of Laser Induced Fluorescence (LIF) experiments using the combination of high rep-rate YAG–Dye laser systems with a well defined and easily controllable surfatron induced plasma setup. The high rep-rate favors the photon

  16. Laser-Induced Fluorescence Decay of 2-Methyl-, 2-Methoxy-, and 2-Ethylnaphthlene on α-Alumina during Temperature Programmed Desorption

    Directory of Open Access Journals (Sweden)

    Bradly B. Baer

    2013-01-01

    Full Text Available The decay of electronically excited molecular films of 2-methylnaphthalene (2-MN, 2-methoxynaphthalene (2-MeON, and 2-ethylnaphthalene (2-EN on a crystal of α-alumina was monitored as a function of temperature with temperature programmed desorption (TPD experiments. By assuming an exponential decay, the rate constants of the relaxation to the ground state were observed to have two components (±20% by laser induced fluorescence (LIF. For the 2-MeON, 2-MN, and 2-EN excimer, the longer components were 35, 25, and 23 × 106 s−1, respectively. Rate constants for the trap fluorescence for 2-MeON, 2-MN, and 2-EN were 100, 44, and 23×106 s−1, respectively. In separate experiments, the effect of a molecule that does not fluoresce and has a lower desorption temperature than the fluorophores was studied by deposition of a bilayer. 1-Chlorohexane (1-CH was chosen as the second layer to the fluorophore and the results gave clues to the complexity of the surface dynamics that occur as the surface is heated. For these bilayer systems, a second excimer formed during the TPD subsequent to the desorption of 1-CH, and their rates are given in parenthesis: for 2-MeON, 2-MN, and 2-EN, the long components were 30 (36, 25 (45, and 23 (42 × 106 s−1, respectively.

  17. Laser Induced Fluorescence (LIF) Measurements of Neutral (ArI) and singly-ionized (ArII) Argon in a LargeScale Helicon Plasma

    Science.gov (United States)

    Kelly, R. F.; Fisher, D. M.; Hatch, M. W.; Gilmore, M.; Dwyer, R. H.; Meany, K.; Zhang, Y.; Desjardins, T. R.

    2017-10-01

    In order to investigate the role of neutral dynamics in helicon discharges in the HelCat (Helicon-Cathode) plasma device at U. New Mexico, a Laser Induced Fluorescence (LIF) system has been developed. The LIF system is based on a >250 mW, tunable diode laser with a tuning range between 680 and 700nm. For neutral Argon, the laser pumps the metastable (2P3/20) 4s level to the (2P1/20) 4p level using 696. 7352 nm light. The fluorescence radiation from decay to the (2P1/20) 4s level at 772. 6333 nm is observed. For singly ionized Argon, the laser pumps the 3s23p4(3 P)3d level to the 3s23p4(3 P)4p level using 686.3162nm light. The fluorescence radiation from the decay to the 3s23p4(3 P)4s level is observed. The system design, and velocity measurements in the axial, azimuthal and radial directions for ArI, and in the axial direction for ArII will be presented. Supported by U.S. National Science Foundation Award 1500423.

  18. Development of the spectrometric imaging apparatus of laser induced fluorescence from plants and estimation of chlorophyll contents of rice leaves; Laser reiki keiko sokutei sochi no kaihatsu to inehanai no chlorophyll ganryo no suitei

    Energy Technology Data Exchange (ETDEWEB)

    Nakaya, K.; Shoji, K.; Hanyu, H.

    1999-05-01

    Photosynthetic activity of plants is an important factor to assess the micrometeorological effect of plant canopy or to estimate the influence of circumstances such as water stress. Light illumination induces fluorescence from a leaf or suspension of chloroplasts. The red chlorophyll fluorescence had been used to determine the process of the electron transportation in photosynthetic reaction. The fluorescence source other than chlorophyll is not announced sufficiently, but is supposed to be useful to determine the contents of the substance corresponding to physiological response of plants. We developed a fluorescence imaging apparatus to observe spectrum and distribution of laser induced fluorescence from a leaf. Pulsed UV-laser (Nd:YAG) induced blue-green fluorescence and red chlorophyll fluorescence from a green leaf. The pulse modulated measuring light and CCD with image-intensifier (ICCD) enable to detect the fluorescence from plants under illumination. The laser induced fluorescence (LIF) spectra were investigated to estimate the chlorophyll contents in leaves of rice. During the greening course of dark grown etiolated rice leaves, chlorophyll contents were determined using the extraction of leaves and steady state LIF spectra were measured. As a result, the ratio of fluorescent intensity between blue-green and red peaks (F460/F740 and F510/F740) decreased in proportion to alteration of chlorophyll contents respectively. These fluorescence intensity ratios perform more precise estimation of higher chlorophyll contents of leaves than reported red chlorophyll fluorescence intensity ratio (F690/E740). (author)

  19. 3D characterisation of the gaseous and liquid phase using laser-induced exciplex fluorescence (LIEF) tomography; Dreidimensionale Charakterisierung der Gas- und Fluessigphase mittels laserinduzierter Exciplexfluoreszenz (LIEF) Tomografie

    Energy Technology Data Exchange (ETDEWEB)

    Rogler, P.; Grzeszik, R.; Arndt, S. [Robert Bosch GmbH, Stuttgart (Germany); Waidmann, C. [Fachhochschule Aalen (Germany); Aigner, M. [DLR, Stuttgart (Germany). Inst. fuer Verbrennungstechnik

    2007-07-01

    The quality of mixture formation in gasoline engines has a significant influence on combustion, emissions and mileage. The measurement technique used for mixture formation analysis of both liquid and vapor phase is laser induced exciplex fluorescence (LIEF), where the aromatics TMPD and naphthalene are added to a non-fluorescing model fuel free of aromatic compounds. For spatially high-resolved measurements of liquid and vapor phase this technique was extended from planar to volume information via tomography. This new approach requires fundamental studies of tracer behavior and new evaluation algorithms for reliable signal interpretation of fluid dynamics in sprays. Using this measurement technique GDI sprays are investigated at a typical stratified engine operation point at part load. For the different injector types, e.g. multi hole and annular orifice injector, an optimal illumination is crucial. With the collected data the spray volume can be calculated, mixture homogeneity can be evaluated and, using a few assumptions, the air/fuel ratio {lambda} can be computed. (orig.)

  20. Laser-induced fluorescence imaging of subsurface tissue structures with a volume holographic spatial-spectral imaging system.

    Science.gov (United States)

    Luo, Yuan; Gelsinger-Austin, Paul J; Watson, Jonathan M; Barbastathis, George; Barton, Jennifer K; Kostuk, Raymond K

    2008-09-15

    A three-dimensional imaging system incorporating multiplexed holographic gratings to visualize fluorescence tissue structures is presented. Holographic gratings formed in volume recording materials such as a phenanthrenquinone poly(methyl methacrylate) photopolymer have narrowband angular and spectral transmittance filtering properties that enable obtaining spatial-spectral information within an object. We demonstrate this imaging system's ability to obtain multiple depth-resolved fluorescence images simultaneously.

  1. Ratiometric, single-dye, pH-sensitive inhibited laser-induced fluorescence for the characterization of mixing and mass transfer

    Science.gov (United States)

    Lacassagne, Tom; Simoëns, Serge; El Hajem, Mahmoud; Champagne, Jean-Yves

    2018-01-01

    Inhibited planar laser-induced fluorescence (I-PLIF) techniques are widely used for heat and mass transfer studies in fluid mechanics. They allow the visualization of instantaneous two-dimensional field of a passive or reactive scalar, providing that this scalar acts as an inhibitor to the fluorescence of a specific molecule, and that this molecule is homogeneously mixed in the fluid at a known concentration. Local scalar values are deduced from fluorescence recordings thanks to preliminary calibration procedure. When confronted with non-optically thin systems, however, the knowledge of the excitation intensity distribution in the region of interest is also required, and this information is most of the time hard to obtain. To overcome that problem, two-color ratiometric PLIF techniques ( {I}^ {r}-PLIF) have been developed. In these methods, the ratio of two different fluorescence wavelengths triggered by the same excitation is used as an indicator of the scalar value. Such techniques have been used for temperature measurements in several studies but never, to the author's knowledge, for pH tracking and acid-base mixing, despite the frequent use of the one-color version in mass transfer studies. In the present work, a ratiometric pH-sensitive-inhibited PLIF technique ( {I}_ {pH}^ {r}-PLIF) using fluorescein sodium as a single dye and applicable to complex geometries and flows is developed. Theoretical considerations show that the ratio of the two-color fluorescence intensities should only depend on the dye's spectral quantum yield, itself pH-dependent. A detailed spectrofluorimetric study of fluorescein reveals that this ratio strictly increases with the pH for two well-chosen spectral bands (fluorescence colors). A similar trend is found when using sCmos cameras equipped with optical filters to record fluorescence signals. The method is then experimented on a test flow, a turbulent acidic jet injected in an initially pH-neutral volume of fluid. The results obtained

  2. Direct on-strip analysis of size- and time-resolved aerosol impactor samples using laser induced fluorescence spectra excited at 263 and 351 nm

    International Nuclear Information System (INIS)

    Wang, Chuji; Pan, Yong-Le; James, Deryck; Wetmore, Alan E.; Redding, Brandon

    2014-01-01

    Highlights: • A dual wavelength UV-LIF spectra-rotating drum impactor (RDI) technique was developed. • The technique was demonstrated by direct on-strip analysis of size- and time-resolved LIF spectra of atmospheric aerosol particles. • More than 2000 LIF spectra of atmospheric aerosol particles collected over three weeks in Djibouti were obtained and assigned to various fluorescence clusters. • The LIF spectra showed size- and time-sensitivity behavior with a time resolution of 3.6 h. - Abstract: We report a novel atmospheric aerosol characterization technique, in which dual wavelength UV laser induced fluorescence (LIF) spectrometry marries an eight-stage rotating drum impactor (RDI), namely UV-LIF-RDI, to achieve size- and time-resolved analysis of aerosol particles on-strip. The UV-LIF-RDI technique measured LIF spectra via direct laser beam illumination onto the particles that were impacted on a RDI strip with a spatial resolution of 1.2 mm, equivalent to an averaged time resolution in the aerosol sampling of 3.6 h. Excited by a 263 nm or 351 nm laser, more than 2000 LIF spectra within a 3-week aerosol collection time period were obtained from the eight individual RDI strips that collected particles in eight different sizes ranging from 0.09 to 10 μm in Djibouti. Based on the known fluorescence database from atmospheric aerosols in the US, the LIF spectra obtained from the Djibouti aerosol samples were found to be dominated by fluorescence clusters 2, 5, and 8 (peaked at 330, 370, and 475 nm) when excited at 263 nm and by fluorescence clusters 1, 2, 5, and 6 (peaked at 390 and 460 nm) when excited at 351 nm. Size- and time-dependent variations of the fluorescence spectra revealed some size and time evolution behavior of organic and biological aerosols from the atmosphere in Djibouti. Moreover, this analytical technique could locate the possible sources and chemical compositions contributing to these fluorescence clusters. Advantages, limitations, and

  3. Direct on-strip analysis of size- and time-resolved aerosol impactor samples using laser induced fluorescence spectra excited at 263 and 351 nm

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chuji [U.S. Army Research Laboratory, Adelphi, MD 20783 (United States); Mississippi State University, Starkville, MS, 39759 (United States); Pan, Yong-Le, E-mail: yongle.pan.civ@mail.mil [U.S. Army Research Laboratory, Adelphi, MD 20783 (United States); James, Deryck; Wetmore, Alan E. [U.S. Army Research Laboratory, Adelphi, MD 20783 (United States); Redding, Brandon [Yale University, New Haven, CT 06510 (United States)

    2014-04-01

    Highlights: • A dual wavelength UV-LIF spectra-rotating drum impactor (RDI) technique was developed. • The technique was demonstrated by direct on-strip analysis of size- and time-resolved LIF spectra of atmospheric aerosol particles. • More than 2000 LIF spectra of atmospheric aerosol particles collected over three weeks in Djibouti were obtained and assigned to various fluorescence clusters. • The LIF spectra showed size- and time-sensitivity behavior with a time resolution of 3.6 h. - Abstract: We report a novel atmospheric aerosol characterization technique, in which dual wavelength UV laser induced fluorescence (LIF) spectrometry marries an eight-stage rotating drum impactor (RDI), namely UV-LIF-RDI, to achieve size- and time-resolved analysis of aerosol particles on-strip. The UV-LIF-RDI technique measured LIF spectra via direct laser beam illumination onto the particles that were impacted on a RDI strip with a spatial resolution of 1.2 mm, equivalent to an averaged time resolution in the aerosol sampling of 3.6 h. Excited by a 263 nm or 351 nm laser, more than 2000 LIF spectra within a 3-week aerosol collection time period were obtained from the eight individual RDI strips that collected particles in eight different sizes ranging from 0.09 to 10 μm in Djibouti. Based on the known fluorescence database from atmospheric aerosols in the US, the LIF spectra obtained from the Djibouti aerosol samples were found to be dominated by fluorescence clusters 2, 5, and 8 (peaked at 330, 370, and 475 nm) when excited at 263 nm and by fluorescence clusters 1, 2, 5, and 6 (peaked at 390 and 460 nm) when excited at 351 nm. Size- and time-dependent variations of the fluorescence spectra revealed some size and time evolution behavior of organic and biological aerosols from the atmosphere in Djibouti. Moreover, this analytical technique could locate the possible sources and chemical compositions contributing to these fluorescence clusters. Advantages, limitations, and

  4. Optimal buffer gas pressure for laser-induced fluorescence detection of the iodine-129 isotope in the atmosphere

    International Nuclear Information System (INIS)

    Kireev, S.V.; Pit'ko, A.V.; Shnyrev, S.L.

    1995-01-01

    The effect of atmospheric air pressure on the intensity of iodine-129 vapor fluorescence excited by a He-Ne (633 nm) laser is studied. It is shown that to achieve the maximum intensity of fluorescence of molecular iodine-129, it is advantageous, first, to use a 3 He- 20 Ne laser for excitation, and second, to detect atmospheric iodine impurities in the gas mixture under analysis evacuated to 2 x 10 18 - 4 x 10 18 mol/cm 3 . In this case, the sensitivity increases about twofold. 7 refs., 4 figs

  5. Detection of carbon monoxide (CO) in sooting hydrocarbon flames using femtosecond two-photon laser-induced fluorescence (fs-TPLIF)

    Science.gov (United States)

    Wang, Yejun; Kulatilaka, Waruna D.

    2018-01-01

    Ultrashort-pulse, femtosecond (fs)-duration, two-photon laser-induced fluorescence (fs-TPLIF) measurements of carbon monoxide (CO) are reported in rich, sooting hydrocarbon flames. CO-TPLIF detection using conventional nanosecond or picosecond lasers are often plagued by photochemical interferences, specifically under fuel-rich flames conditions. In the current study, we investigate the commonly used CO two-photon excitation scheme of the B1Σ+ ← X1Σ+ electronic transition, using approximately 100-fs-duration excitation pulses. Fluorescence emission was observed in the Ångström band originating from directly populated B1Σ+ upper state, as well as, in the third positive band from collisionally populated b3Σ+ upper state. The current work was focused on the Ångström band emission. Interference from nascent C2 emissions originating from hot soot particles in the flame could be reduced to a negligible level using a narrower detection gate width. In contrast, avoiding interferences from laser-generated C2 Swan-band emissions required specific narrowband spectral filtering in sooting flame conditions. The observed less than quadratic laser pulse energy dependence of the TPLIF signal suggests the presence of strong three-photon ionization and stimulated emission processes. In a range of CH4/air and C2H4/air premixed flames investigated, the measured CO fluorescence signals agree well with the calculated equilibrium CO number densities. Reduced-interference CO-TPLIF imaging in premixed C2H4/O2/N2 jet flames is also reported.

  6. Immuno-magnetic beads-based extraction-capillary zone electrophoresis-deep UV laser-induced fluorescence analysis of erythropoietin.

    Science.gov (United States)

    Wang, Heye; Dou, Peng; Lü, Chenchen; Liu, Zhen

    2012-07-13

    Erythropoietin (EPO) is an important glycoprotein hormone. Recombinant human EPO (rhEPO) is an important therapeutic drug and can be also used as doping reagent in sports. The analysis of EPO glycoforms in pharmaceutical and sports areas greatly challenges analytical scientists from several aspects, among which sensitive detection and effective and facile sample preparation are two essential issues. Herein, we investigated new possibilities for these two aspects. Deep UV laser-induced fluorescence detection (deep UV-LIF) was established to detect the intrinsic fluorescence of EPO while an immuno-magnetic beads-based extraction (IMBE) was developed to specifically extract EPO glycoforms. Combined with capillary zone electrophoresis (CZE), CZE-deep UV-LIF allows high resolution glycoform profiling with improved sensitivity. The detection sensitivity was improved by one order of magnitude as compared with UV absorbance detection. An additional advantage is that the original glycoform distribution can be completely preserved because no fluorescent labeling is needed. By combining IMBE with CZE-deep UV-LIF, the overall detection sensitivity was 1.5 × 10⁻⁸ mol/L, which was enhanced by two orders of magnitude relative to conventional CZE with UV absorbance detection. It is applicable to the analysis of pharmaceutical preparations of EPO, but the sensitivity is insufficient for the anti-doping analysis of EPO in blood and urine. IMBE can be straightforward and effective approach for sample preparation. However, antibodies with high specificity were the key for application to urine samples because some urinary proteins can severely interfere the immuno-extraction. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Standard Reference Line Combined with One-Point Calibration-Free Laser-Induced Breakdown Spectroscopy (CF-LIBS) to Quantitatively Analyze Stainless and Heat Resistant Steel.

    Science.gov (United States)

    Fu, Hongbo; Wang, Huadong; Jia, Junwei; Ni, Zhibo; Dong, Fengzhong

    2018-01-01

    Due to the influence of major elements' self-absorption, scarce observable spectral lines of trace elements, and relative efficiency correction of experimental system, accurate quantitative analysis with calibration-free laser-induced breakdown spectroscopy (CF-LIBS) is in fact not easy. In order to overcome these difficulties, standard reference line (SRL) combined with one-point calibration (OPC) is used to analyze six elements in three stainless-steel and five heat-resistant steel samples. The Stark broadening and Saha - Boltzmann plot of Fe are used to calculate the electron density and the plasma temperature, respectively. In the present work, we tested the original SRL method, the SRL with the OPC method, and intercept with the OPC method. The final calculation results show that the latter two methods can effectively improve the overall accuracy of quantitative analysis and the detection limits of trace elements.

  8. Qualitative tissue differentiation by analysing the intensity ratios of atomic emission lines using laser induced breakdown spectroscopy (LIBS): prospects for a feedback mechanism for surgical laser systems.

    Science.gov (United States)

    Kanawade, Rajesh; Mahari, Fanuel; Klämpfl, Florian; Rohde, Maximilian; Knipfer, Christian; Tangermann-Gerk, Katja; Adler, Werner; Schmidt, Michael; Stelzle, Florian

    2015-01-01

    The research work presented in this paper focuses on qualitative tissue differentiation by monitoring the intensity ratios of atomic emissions using 'Laser Induced Breakdown Spectroscopy' (LIBS) on the plasma plume created during laser tissue ablation. The background of this study is to establish a real time feedback control mechanism for clinical laser surgery systems during the laser ablation process. Ex-vivo domestic pig tissue samples (muscle, fat, nerve and skin) were used in this experiment. Atomic emission intensity ratios were analyzed to find a characteristic spectral line for each tissue. The results showed characteristic elemental emission intensity ratios for the respective tissues. The spectral lines and intensity ratios of these specific elements varied among the different tissue types. The main goal of this study is to qualitatively and precisely identify different tissue types for tissue specific laser surgery. © 2015 The Authors. Journal of Biophotonics published by WILEY-VCH Verlag.

  9. Simultaneous detection of ultraviolet B-induced DNA damage using capillary electrophoresis with laser-induced fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Guthrie, Jeffrey W., E-mail: jeff.guthrie@emich.edu; Limmer, Robert T.; Brooks, Eric A.; Wisnewski, Chelsea C.; Loggins-Davis, Nnekia D.; Bouzid, Abderraouf

    2015-01-01

    Highlights: • CE–LIF was developed for simultaneous detection of UV-induced DNA photoproducts. • Fluorescent quantum dot reporters enabled detection of small amounts of photoproducts. • Photoproducts were detected after 65 J m{sup −2} of fluence from a UVB lamp in ∼6 ng of DNA. • Natural sunlight induced cyclobutane pyrimidine dimers after only 15 min of exposure. - Abstract: An immunoassay based on CE–LIF was developed for the simultaneous detection of cyclobutane pyrimidine dimers (CPDs) and pyrimidine 6-4 pyrimidone photoproducts (6-4PPs) in genomic DNA irradiated with UVB or natural sunlight. Human cells were first exposed to varying amounts of UVB or natural sunlight to induce DNA damage. Genomic DNA was extracted and incubated with anti-CPD and anti-6-4PP primary antibodies attached to secondary antibodies with a fluorescent quantum dot (QD) reporter that emitted either red or yellow fluorescence. CE was used to separate the unbound antibodies from those bound to the photoproducts, and LIF with appropriate optical filters was used to separate the fluorescence signals from each QD to individual photomultiplier tubes for simultaneous photoproduct detection. Using this strategy, photoproducts were detected from ∼6 ng (200 ng μL{sup −1}) of DNA under a low UVB fluence of 65 J m{sup −2} for CPDs or 195 J m{sup −2} for 6-4PPs. This assay was also the first to demonstrate the detection of CPDs in human cells after only 15 min of irradiation under natural sunlight.

  10. Simultaneous detection of ultraviolet B-induced DNA damage using capillary electrophoresis with laser-induced fluorescence

    International Nuclear Information System (INIS)

    Guthrie, Jeffrey W.; Limmer, Robert T.; Brooks, Eric A.; Wisnewski, Chelsea C.; Loggins-Davis, Nnekia D.; Bouzid, Abderraouf

    2015-01-01

    Highlights: • CE–LIF was developed for simultaneous detection of UV-induced DNA photoproducts. • Fluorescent quantum dot reporters enabled detection of small amounts of photoproducts. • Photoproducts were detected after 65 J m −2 of fluence from a UVB lamp in ∼6 ng of DNA. • Natural sunlight induced cyclobutane pyrimidine dimers after only 15 min of exposure. - Abstract: An immunoassay based on CE–LIF was developed for the simultaneous detection of cyclobutane pyrimidine dimers (CPDs) and pyrimidine 6-4 pyrimidone photoproducts (6-4PPs) in genomic DNA irradiated with UVB or natural sunlight. Human cells were first exposed to varying amounts of UVB or natural sunlight to induce DNA damage. Genomic DNA was extracted and incubated with anti-CPD and anti-6-4PP primary antibodies attached to secondary antibodies with a fluorescent quantum dot (QD) reporter that emitted either red or yellow fluorescence. CE was used to separate the unbound antibodies from those bound to the photoproducts, and LIF with appropriate optical filters was used to separate the fluorescence signals from each QD to individual photomultiplier tubes for simultaneous photoproduct detection. Using this strategy, photoproducts were detected from ∼6 ng (200 ng μL −1 ) of DNA under a low UVB fluence of 65 J m −2 for CPDs or 195 J m −2 for 6-4PPs. This assay was also the first to demonstrate the detection of CPDs in human cells after only 15 min of irradiation under natural sunlight

  11. Simultaneous detection of ultraviolet B-induced DNA damage using capillary electrophoresis with laser-induced fluorescence.

    Science.gov (United States)

    Guthrie, Jeffrey W; Limmer, Robert T; Brooks, Eric A; Wisnewski, Chelsea C; Loggins-Davis, Nnekia D; Bouzid, Abderraouf

    2015-01-01

    An immunoassay based on CE-LIF was developed for the simultaneous detection of cyclobutane pyrimidine dimers (CPDs) and pyrimidine 6-4 pyrimidone photoproducts (6-4PPs) in genomic DNA irradiated with UVB or natural sunlight. Human cells were first exposed to varying amounts of UVB or natural sunlight to induce DNA damage. Genomic DNA was extracted and incubated with anti-CPD and anti-6-4PP primary antibodies attached to secondary antibodies with a fluorescent quantum dot (QD) reporter that emitted either red or yellow fluorescence. CE was used to separate the unbound antibodies from those bound to the photoproducts, and LIF with appropriate optical filters was used to separate the fluorescence signals from each QD to individual photomultiplier tubes for simultaneous photoproduct detection. Using this strategy, photoproducts were detected from ∼6 ng (200 ng μL(-1)) of DNA under a low UVB fluence of 65 J m(-2) for CPDs or 195 J m(-2) for 6-4PPs. This assay was also the first to demonstrate the detection of CPDs in human cells after only 15 min of irradiation under natural sunlight. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Investigation by laser induced breakdown spectroscopy, X-ray fluorescence and X-ray powder diffraction of the chemical composition of white clay ceramic tiles from Veliki Preslav

    International Nuclear Information System (INIS)

    Blagoev, K.; Grozeva, M.; Malcheva, G.; Neykova, S.

    2013-01-01

    The paper presents the results of the application of laser induced breakdown spectroscopy, X-ray fluorescence spectrometry, and X-ray powder diffraction in assessing the chemical and phase composition of white clay decorative ceramic tiles from the medieval archaeological site of Veliki Preslav, a Bulgarian capital in the period 893–972 AC, well-known for its original ceramic production. Numerous white clay ceramic tiles with highly varied decoration, produced for wall decoration of city's churches and palaces, were found during the archaeological excavations in the old capital. The examination of fourteen ceramic tiles discovered in one of the city's monasteries is aimed at characterization of the chemical profile of the white-clay decorative ceramics produced in Veliki Preslav. Combining different methods and comparing the obtained results provides complementary information regarding the white-clay ceramic production in Veliki Preslav and complete chemical characterization of the examined artefacts. - Highlights: ► LIBS, XRF and XRD analyses of medieval white-clay ceramic tiles fragments are done. ► Different elements and phases, presented in the ceramics fragments were determined. ► Differences in the tiles' raw material mineral composition are found. ► Information of the tiles' production process and the raw clay deposits is obtained

  13. Determination of Conjugation Efficiency of Antibodies and Proteins to the Superparamagnetic Iron Oxide Nanoparticles by Capillary Electrophoresis with Laser-Induced Fluorescence Detection

    Energy Technology Data Exchange (ETDEWEB)

    Wang, F.-H.; Yoshitake, Takashi [Karolinska Institutet, Department of Neuroscience (Sweden); Kim, Do-Kyung; Muhammed, Mamoun [Royal Institute of Technology, Materials Chemistry Division (Sweden); Bjelke, Boerje [MRI-Center, Experimental Unit, Karolinska Institutet (Sweden); Kehr, Jan [Karolinska Institutet, Department of Neuroscience (Sweden)], E-mail: Jan.Kehr@neuro.ki.se

    2003-04-15

    The method based on capillary electrophoresis with laser-induced fluorescence detection (CE/LIF) was developed for determination of magnetic iron oxide nanoparticles (hydrodynamic diameters of 100 nm) functionalized with molecules containing primary amino groups. The magnetic nanoparticles with carboxylic or aminopropyl-trimethoxysilane groups at their surface were conjugated to the model proteins (bovine serum albumin, BSA; streptavidin or goat anti-rabbit immunoglobulin G, IgG) using carbodiimide as a zero-length cross-linker.The nanoparticle-protein conjugates (hydrodynamic diameter 163-194 nm) were derivatized with naphthalene-2,3-dicarboxaldehyde reagent and separated by CE/LIF with a helium-cadmium laser (excitation at 442 nm, emission at 488 nm). The separations were carried out by using a fused-silica capillary (effective length 48 cm, inner diameter 75 um) and 100 mM sodium borate buffer (pH 9.2), the potential was 30 kV. The detection limit for BSA-conjugate was 1.3 pg/10 nl, i.e. about 20 amol. The present method provides an efficient and fast tool for sensitive determination of the efficacy of biomolecular functionalization of magnetic nanoparticles. The CE/LIF technique requires only negligible sample volumes for analysis, which is especially suitable for controlling the process of preparation of functionalized nanoparticles with unique properties aimed to be used for diagnostic or therapeutic purposes.

  14. Analysis of heterogeneous gallstones using laser-induced breakdown spectroscopy (LIBS) and wavelength dispersive X-ray fluorescence (WD-XRF).

    Science.gov (United States)

    Jaswal, Brij Bir S; Kumar, Vinay; Sharma, Jitendra; Rai, Pradeep K; Gondal, Mohammed A; Gondal, Bilal; Singh, Vivek K

    2016-04-01

    Laser-induced breakdown spectroscopy (LIBS) is an emerging analytical technique with numerous advantages such as rapidity, multi-elemental analysis, no specific sample preparation requirements, non-destructiveness, and versatility. It has been proven to be a robust elemental analysis tool attracting interest because of being applied to a wide range of materials including biomaterials. In this paper, we have performed spectroscopic studies on gallstones which are heterogeneous in nature using LIBS and wavelength dispersive X-ray fluorescence (WD-XRF) techniques. It has been observed that the presence and relative concentrations of trace elements in different kind of gallstones (cholesterol and pigment gallstones) can easily be determined using LIBS technique. From the experiments carried out on gallstones for trace elemental mapping and detection, it was found that LIBS is a robust tool for such biomedical applications. The stone samples studied in the present paper were classified using the Fourier transform infrared (FTIR) spectroscopy. WD-XRF spectroscopy has been applied for the qualitative and quantitative analysis of major and trace elements present in the gallstone which was compared with the LIBS data. The results obtained in the present paper show interesting prospects for LIBS and WD-XRF to study cholelithiasis better.

  15. Solvatochromism and preferential solvation of 1,4-dihydroxy-2,3-dimethyl-9,10-anthraquinone by UV-vis absorption and laser-induced fluorescence measurements

    Science.gov (United States)

    Sasirekha, V.; Vanelle, P.; Terme, T.; Ramakrishnan, V.

    2008-12-01

    Solvation characteristics of 1,4-dihydroxy-2,3-dimethyl-9,10-anthraquinone ( 1) in pure and binary solvent mixtures have been studied by UV-vis absorption spectroscopy and laser-induced fluorescence techniques. The binary solvent mixtures used as CCl 4 (tetrachloromethane)-DMF ( N, N-dimethylformamide), AN (acetonitrile)-DMSO (dimethylsulfoxide), CHCl 3 (chloroform)-DMSO, CHCl 3-MeOH (methanol), and MeOH-DMSO. The longest wavelength band of 1 has been studied in pure solvents as well as in binary solvent mixtures as a function of the bulk mole fraction. The Vis absorption band maxima show an unusual blue shift with increasing solvent polarity. The emission maxima of 1 show changes with varying the pure solvents and the composition in the case of binary solvent mixtures. Non-ideal solvation characteristics are observed in all binary solvent mixtures. It has been observed that the quantity [ ν-(Xν+Xν)] serves as a measure of the extent of preferential solvation, where ν˜ and X are the position of band maximum in wavenumbers (cm -1) and the bulk mole fraction values, respectively. The preferential solvation parameters local mole fraction ( X2L), solvation index ( δs2), and exchange constant ( k12) are evaluated.

  16. Investigation by laser induced breakdown spectroscopy, X-ray fluorescence and X-ray powder diffraction of the chemical composition of white clay ceramic tiles from Veliki Preslav

    Energy Technology Data Exchange (ETDEWEB)

    Blagoev, K., E-mail: kblagoev@issp.bas.bg [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria); Grozeva, M., E-mail: margo@issp.bas.bg [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria); Malcheva, G., E-mail: bobcheva@issp.bas.bg [Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia (Bulgaria); Neykova, S., E-mail: sevdalinaneikova@abv.bg [National Institute of Archaeology with Museum, Bulgarian Academy of Sciences, 2 Saborna, 1000 Sofia (Bulgaria)

    2013-01-01

    The paper presents the results of the application of laser induced breakdown spectroscopy, X-ray fluorescence spectrometry, and X-ray powder diffraction in assessing the chemical and phase composition of white clay decorative ceramic tiles from the medieval archaeological site of Veliki Preslav, a Bulgarian capital in the period 893–972 AC, well-known for its original ceramic production. Numerous white clay ceramic tiles with highly varied decoration, produced for wall decoration of city's churches and palaces, were found during the archaeological excavations in the old capital. The examination of fourteen ceramic tiles discovered in one of the city's monasteries is aimed at characterization of the chemical profile of the white-clay decorative ceramics produced in Veliki Preslav. Combining different methods and comparing the obtained results provides complementary information regarding the white-clay ceramic production in Veliki Preslav and complete chemical characterization of the examined artefacts. - Highlights: ► LIBS, XRF and XRD analyses of medieval white-clay ceramic tiles fragments are done. ► Different elements and phases, presented in the ceramics fragments were determined. ► Differences in the tiles' raw material mineral composition are found. ► Information of the tiles' production process and the raw clay deposits is obtained.

  17. The use of laser-induced fluorescence or ultraviolet detectors for sensitive and selective analysis of tobramycin or erythropoietin in complex samples

    Science.gov (United States)

    Ahmed, Hytham M.; Ebeid, Wael B.

    2015-05-01

    Complex samples analysis is a challenge in pharmaceutical and biopharmaceutical analysis. In this work, tobramycin (TOB) analysis in human urine samples and recombinant human erythropoietin (rhEPO) analysis in the presence of similar protein were selected as representative examples of such samples analysis. Assays of TOB in urine samples are difficult because of poor detectability. Therefore laser induced fluorescence detector (LIF) was combined with a separation technique, micellar electrokinetic chromatography (MEKC), to determine TOB through derivatization with fluorescein isothiocyanate (FITC). Borate was used as background electrolyte (BGE) with negative-charged mixed micelles as additive. The method was successively applied to urine samples. The LOD and LOQ for Tobramycin in urine were 90 and 200 ng/ml respectively and recovery was >98% (n = 5). All urine samples were analyzed by direct injection without sample pre-treatment. Another use of hyphenated analytical technique, capillary zone electrophoresis (CZE) connected to ultraviolet (UV) detector was also used for sensitive analysis of rhEPO at low levels (2000 IU) in the presence of large amount of human serum albumin (HSA). Analysis of rhEPO was achieved by the use of the electrokinetic injection (EI) with discontinuous buffers. Phosphate buffer was used as BGE with metal ions as additive. The proposed method can be used for the estimation of large number of quality control rhEPO samples in a short period.

  18. Kilohertz VLIF (volumetric laser induced fluorescence) measurements in a seeded free gas-phase jet in the transitionally turbulent flow regime

    Science.gov (United States)

    Wu, Yue; Xu, Wenjiang; Ma, Lin

    2018-03-01

    This paper reports the demonstration of instantaneous three-dimension (3D) measurements in turbulent flows at repetition rates up to 10 kHz using VLIF (volumetric laser induced fluorescence). The measurements were performed based on the LIF signal of iodine (I2) vapor seeded in the flow. The LIF signals of I2 vapor were generated volumetrically by a thick laser slab and then simultaneously captured by a total of seven cameras from different perspectives, based on which a 3D tomographic reconstruction was performed to obtain the 3D distribution of I2 vapor concentration. Single-shot measurements obtained in a duration of hundreds of nanoseconds (limited by the pulse duration of the excitation laser) were demonstrated in a 50 × 50 × 50 mm3 at a repetition rate up to 10 kHz. These measurements demonstrated the feasibility and potential of VLIF for resolving the 4D spatiotemporal dynamics of turbulent flows. Based on the experimental results obtained, this work also studied the VLIF signal level and its effects on the reconstruction accuracy under different the measurement conditions, illustrating the capabilities and limitations of performing high speed VLIF measurements.

  19. Determination of gabapentin in human plasma by capillary electrophoresis-laser induced fluorescence detection with and without solid-phase extraction

    International Nuclear Information System (INIS)

    Cao, L.; Liang, S.; Tan, X.; Meng, J.

    2012-01-01

    We have developed two methods for the quantitation of gabapentin in human plasma. They are based on capillary electrophoresis with laser-induced fluorescence detection (CE-LIF) with and without solid-phase extraction (SPE) and the derivatizing reagent 5-(4,6-dichlorotriazinyl)amino fluoresencin. The conditions for derivatization, separation and extraction were investigated in detail, and the optimal labeling conditions include a temperature of 40 0 C, a reaction time of 30 min, and the use of a borate buffer of pH 9.0 as the reaction medium. A borate buffer of pH 9.2 served as a background electrolyte for CE separations. The CE-LIF and SPE-CE-LIF methods have linear ranges of 5-200 nmol L -1 and 0.2-10 nmol L -1 , respectively, and the limits of detection are 0.5 and 0.02 nmol L -1 , respectively. The SPE-CE-LIF method was successfully applied to the determination of gabapentin in blood plasma samples. (author)

  20. Production mechanism of atomic nitrogen in atmospheric pressure pulsed corona discharge measured using two-photon absorption laser-induced fluorescence

    International Nuclear Information System (INIS)

    Teramoto, Yoshiyuki; Ono, Ryo; Oda, Tetsuji

    2012-01-01

    To study the production mechanism of atomic nitrogen, the temporal profile and spatial distribution of atomic nitrogen are measured in atmospheric pressure pulsed positive corona discharge using two-photon absorption laser-induced fluorescence. The absolute atomic nitrogen density in the streamer filaments is estimated from decay rate of atomic nitrogen in N 2 discharge. The results indicate that the absolute atomic nitrogen density is approximately constant against discharge energy. When the discharge voltage is 21.5 kV, production yield of atomic nitrogen produced by an N 2 discharge pulse is estimated to be 2.9 - 9.8 × 10 13 atoms and the energy efficiency of atomic nitrogen production is estimated to be about 1.8 - 6.1 × 10 16 atoms/J. The energy efficiency of atomic nitrogen production in N 2 discharge is constant against the discharge energy, while that in N 2 /O 2 discharge increases with discharge energy. In the N 2 /O 2 discharge, two-step process of N 2 dissociation plays significant role for atomic nitrogen production.

  1. Time-resolved pulse-counting lock-in detection of laser induced fluorescence in the presence of a strong background emission

    International Nuclear Information System (INIS)

    Pelissier, B.; Sadeghi, N.

    1996-01-01

    We describe a time-resolved pulse-counting system well adapted for the detection of continuous laser induced fluorescence (LIF) signals in repetitive phenomena, when a strong background emission is present. It consists of 256 channels coupled to a first in first out memory and interfaced to a 486 DX 33 PC, for data storage. It accepts time-averaged count rates up to 450 kcount/s. Time between channels can be set from 12.5 ns to several μs and the dead time between two consecutive cycles of the physical phenomena is less than 20 ns. In phase with a chopper, which modulates the laser beam, it adds the observed photon signal to the channel memories when the beam is on and substracts it when the beam is stopped, acting like a lock-in amplifier which detect only the modulated part of the signal. The minimum detectivity on the LIF signal is only limited by the shot noise of the plasma induced emission signal. As an application, we studied the time variation of the Ar + *( 2 G 9/2 ) metastable ions, detected by LIF, in two types of plasmas. Their radiative lifetime and collisional quenching frequencies were deduced from their decay rate in the afterglow of a pulsed Helicon reactor. We also observed the evolution of their density in a 455 kHz capacitively coupled argon discharge. copyright 1996 American Institute of Physics

  2. Time-resolved pulse-counting lock-in detection of laser induced fluorescence in the presence of a strong background emission

    Science.gov (United States)

    Pelissier, B.; Sadeghi, N.

    1996-10-01

    We describe a time-resolved pulse-counting system well adapted for the detection of continuous laser induced fluorescence (LIF) signals in repetitive phenomena, when a strong background emission is present. It consists of 256 channels coupled to a first in first out memory and interfaced to a 486 DX 33 PC, for data storage. It accepts time-averaged count rates up to 450 kcount/s. Time between channels can be set from 12.5 ns to several μs and the dead time between two consecutive cycles of the physical phenomena is less than 20 ns. In phase with a chopper, which modulates the laser beam, it adds the observed photon signal to the channel memories when the beam is on and substracts it when the beam is stopped, acting like a lock-in amplifier which detect only the modulated part of the signal. The minimum detectivity on the LIF signal is only limited by the shot noise of the plasma induced emission signal. As an application, we studied the time variation of the Ar+*(2G9/2) metastable ions, detected by LIF, in two types of plasmas. Their radiative lifetime and collisional quenching frequencies were deduced from their decay rate in the afterglow of a pulsed Helicon reactor. We also observed the evolution of their density in a 455 kHz capacitively coupled argon discharge.

  3. Total Peroxy Nitrates (ΣPNs in the atmosphere: the Thermal Dissociation-Laser Induced Fluorescence (TD-LIF technique and comparisons to speciated PAN measurements

    Directory of Open Access Journals (Sweden)

    B. W. LaFranchi

    2010-05-01

    Full Text Available Peroxyacetyl nitrate (PAN and its chemical analogues are increasingly being quantified in the ambient atmosphere by thermal dissociation (TD followed by detection of either the peroxyacyl radical or the NO2 product. Here we present details of the technique developed at University of California, Berkeley which detects the sum of all peroxynitrates (ΣPNs via laser-induced fluorescence (LIF of the NO2 product. We review the various deployments and compare the Berkeley ΣPNs measurements with the sums of PAN and its homologue species detected individually by other instruments. The observed TD-LIF ΣPNs usually agree to within 10% with the summed individual species, thus arguing against the presence of significant concentrations of unmeasured PAN-type compounds in the atmosphere, as suggested by some photochemical mechanisms. Examples of poorer agreement are attributed to a sampling inlet design that is shown to be inappropriate for high NOx conditions. Interferences to the TD-LIF measurements are described along with strategies to minimize their effects.

  4. Graphene oxide-coated stir bar sorptive extraction of trace aflatoxins from soy milk followed by high performance liquid chromatography-laser-induced fluorescence detection.

    Science.gov (United States)

    Ma, Haiyan; Ran, Congcong; Li, Mengjiao; Gao, Jinglin; Wang, Xinyu; Zhang, Lina; Bian, Jing; Li, Junmei; Jiang, Ye

    2018-04-01

    Mycotoxins are potential food pollutants produced by fungi. Among them, aflatoxins (AFs) are the most toxic. Therefore, AFs were selected as models, and a sensitive, simple and green graphene oxide (GO)-based stir bar sorptive extraction (SBSE) method was developed for extraction and determination of AFs with high performance liquid chromatography-laser-induced fluorescence detector (HPLC-LIF). This method improved the sensitivity of AFs detection and solved the deposition difficulty of the direct use of GO as adsorbent. Several parameters including a spiked amount of NaCl, stirring rate, extraction time and desorption time were investigated. Under optimal conditions, the quantitative method had low limits of detection of 2.4-8.0 pg/mL, which were better than some reported AFs analytical methods. The developed method has been applied to soy milk samples with good recoveries ranging from 80.5 to 102.3%. The prepared GO-based SBSE can be used as a sensitive screening technique for detecting AFs in soy milk.

  5. Calibration-Free Laser-Induced Breakdown Spectroscopy (CF-LIBS) with Standard Reference Line for the Analysis of Stainless Steel.

    Science.gov (United States)

    Fu, Hongbo; Dong, Fengzhong; Wang, Huadong; Jia, Junwei; Ni, Zhibo

    2017-08-01

    In this work, calibration-free laser-induced breakdown spectroscopy (CF-LIBS) is used to analyze a certified stainless steel sample. Due to self-absorption of the spectral lines from the major element Fe and the sparse lines of trace elements, it is usually not easy to construct the Boltzmann plots of all species. A standard reference line method is proposed here to solve this difficulty under the assumption of local thermodynamic equilibrium so that the same temperature value for all elements present into the plasma can be considered. Based on the concentration and rich spectral lines of Fe, the Stark broadening of Fe(I) 381.584 nm and Saha-Boltzmann plots of this element are used to calculate the electron density and the plasma temperature, respectively. In order to determine the plasma temperature accurately, which is seriously affected by self-absorption, a pre-selection procedure for eliminating those spectral lines with strong self-absorption is employed. Then, one spectral line of each element is selected to calculate its corresponding concentration. The results from the standard reference lines with and without self-absorption of Fe are compared. This method allows us to measure trace element content and effectively avoid the adverse effects due to self-absorption.

  6. Curves of growth of spectral lines emitted by a laser-induced plasma: influence of the temporal evolution and spatial inhomogeneity of the plasma

    Energy Technology Data Exchange (ETDEWEB)

    Aguilera, J.A.; Bengoechea, J.; Aragon, C. E-mail: carlos.aragon@unavarra.es

    2003-02-03

    The curves of growth (COG) of five Fe I lines emitted from a laser-induced plasma, generated with Fe-Ni alloys in air at atmospheric pressure, have been investigated. Spectral lines with different energy levels and line widths, emitted with a broad range of optical depths, have been included in the study in order to check the validity of theoretical models proposed for COG generation, based in the radiative transfer within a plasma in local thermodynamic equilibrium. The COGs have been measured at time windows of 4-5 {mu}s and 15-18 {mu}s. The Stark widths of the Fe I lines have been obtained, and the line widths have been determined by measuring the plasma electron density at the time windows selected. It is shown that at a time window of 4-5 {mu}s, the inhomogeneity of the plasma magnitudes has an important influence on the COGs of intense lines. For this time window, a two-region model of the plasma has been used to generate theoretical COGs that describe satisfactorily the experimental curves of all the lines using a single set of plasma parameters. The results reveal the existence of considerable gradients between the inner and the outer plasma regions in the temperature (9400-7800 K) and in the density of Fe atoms (4x10{sup 16}-0.02x10{sup 16} cm{sup -3} for a sample with 100% Fe). On the contrary, at the time window 15-18 {mu}s, at which the plasma has suffered most of its expansion and cooling process, the COGs of all the lines may be described by a single-region model, corresponding to a plasma with uniform temperature (6700 K) and density of Fe atoms (0.06x10{sup 16} cm{sup -3} for a sample with 100% Fe). It is also shown that at initial times, the plasma inhomogeneity has an important effect in the line profiles of intense spectral lines, which are described by using the two-region model of the laser-induced plasma.

  7. Fluorescence line-narrowing studies of rare earths in disordered solids

    International Nuclear Information System (INIS)

    Hall, D.W.

    1982-01-01

    This dissertation is made up of two experimental studies dealing with apparently diverse topics within the subject of rare earths (RE) in solids. The first study, described in Part II, concerns the vibrations of a disordered host material about an optically active rare-earth ion as manifested by vibrationally-assisted-electronic, or vibronic transitions. Part III of the dissertation describes an investigation of the influence of site anisotropy on the purely electronic, laser transition of Nd 3+ in glass. These two studies are bound together by the common experimental technique of laser-induced fluorescence line narrowing (FLN). By exciting fluorescence with monochromatic light of well-characterized polarization, one may select and observe the response of a single subset of the optically active ions and obtain information that is usually masked by the inhomogeneous nature of disordered solids

  8. Laser induced fluorescence emission (L.I.F.E.): in situ and remote detection of life in Antarctic and Alaskan ice

    Science.gov (United States)

    Storrie-Lombardi, Michael C.; Sattler, Birgit

    2009-08-01

    Once thought to be a barren desert devoid of life, it now appears that Earth's cryosphere is an ice ecosystem harbouring a rich community of metabolically active microorganisms inhabiting ice, snow, water, and lithic environments. The ability to rapidly survey this ecosystem during in situ and orbital missions is of considerable interest for monitoring Earth's carbon budget and for efficiently searching for life on Mars or any exoplanet with an analogous cryosphere. Laser induced fluorescence emission (L.I.F.E.) imaging and spectroscopy using excitation in ultraviolet (UV) wavelengths have been proposed as non-destructive astrobiological survey tools to search for amino acids, nucleic acids, microbial life, and polycyclic aromatic hydrocarbons (PAHs) deep in the Mars regolith. However, the technique is easily adapted to search for larger, more complex biomolecular targets using longer wavelength sources. Of particular interest is the ability for excitation at blue, green, and red wavelengths to produce visible and near infrared fluorescence of photosynthetic pigments in cyanobacteria-dominated microbial communities populating the ice of alpine, Arctic, and Antarctic lakes, glaciers, ice sheets, and even the supercooled water-ice droplets of clouds. During the Tawani 2008 International Antarctic Expedition we tested the in situ use of the technique as part of a field campaign in the Dry Valleys of Schirmacher Oasis and Lake Untersee, Queen Maud Land, Antarctica. In the spring of 2009, we performed airborne remote sensing tests of the technology in Alaska. In this paper we review our in situ laser detection experiments and present for the first time preliminary results on our efforts to detect cryosphere L.I.F.E. from an airborne platform.

  9. Optical-optical double resonance, laser induced fluorescence, and revision of the signs of the spin-spin constants of the boron carbide (BC) free radical

    Science.gov (United States)

    Sunahori, Fumie X.; Nagarajan, Ramya; Clouthier, Dennis J.

    2015-12-01

    The cold boron carbide free radical (BC X 4Σ-) has been produced in a pulsed discharge free jet expansion using a precursor mixture of trimethylborane in high pressure argon. High resolution laser induced fluorescence spectra have been obtained for the B 4Σ--X 4Σ- and E 4Π-X 4Σ- band systems of both 11BC and 10BC. An optical-optical double resonance (OODR) scheme was implemented to study the finer details of both band systems. This involved pumping a single rotational level of the B state with one laser and then recording the various allowed transitions from the intermediate B state to the final E state with a second laser by monitoring the subsequent E-X ultraviolet fluorescence. In this fashion, we were able to prove unambiguously that, contrary to previous studies, the spin-spin constant λ is negative in the ground state and positive in the B 4Σ- excited state. It has been shown that λ″ expected based on a semiempirical second order perturbation theory calculation of the magnitude of the spin-spin constant. The OODR spectra have also been used to validate our assignments of the complex and badly overlapped E 4Π-X 4Σ- 0-0 and 1-0 bands of 11BC. The E-X 0-0 band of 10BC was found to be severely perturbed. The ground state main electron configuration is …3σ24σ25σ11π22π0 and the derived bond lengths show that there is a 0.03 Å contraction in the B state, due to the promotion of an electron from the 4σ antibonding orbital to the 5σ bonding orbital. In contrast, the bond length elongates by 0.15 Å in the E state, a result of promoting an electron from the 5σ bonding orbital to the 2π antibonding orbitals.

  10. Laser-induced-fluorescence imaging of NO in a eta-heptane- and diesel-fuel-driven diesel engine

    NARCIS (Netherlands)

    Brugman, T.M.; Klein-Douwel, R.J.H.; Huigen, G.; Walwijk, van E.; Meulen, ter J.J.

    1993-01-01

    Continuous on-line imaging by 2D-LIF techniques of in-cylinder NO distributions in a running Diesel engine is explored using an ArF-excimer laser at 193 nm operating at low power. For the first time NO excitation spectra could be measured as a result of high optical transparencies during

  11. On-line determination of iodine in nuclear fuel reprocessing off-gas streams by a combination of laser-induced fluorimetry and laser photoacoustic spectroscopy

    International Nuclear Information System (INIS)

    Kuno, Yusuke; Sato, Souichi; Masui, Jinichi

    1992-01-01

    The on-line determination of molecular iodine and organic iodides in nuclear fuel reprocessing off-gas streams containing high concentrations of NO x gas was studied. Ultraviolet radiation is used to convert organic iodides into molecular iodine. The approximate concentration of iodine before and after the photochemical conversion in the presence of NO x gas was first determined by laser-induced fluorimetry. NO 2 was determined by photoacoustic spectroscopy, correcting the acoustic signal due to iodine by using the approximate iodine concentration. NO was determined from the concentrations of NO 2 before and after the photoirradiation based on the photochemical fraction changes of NO and NO 2 . The quenching of the fluorimetry due to NO and NO 2 was finally corrected with the NO and NO 2 concentrations obtained. The detection limit of the proposed method is 10 nl 1 -1 . 7 figs., 2 tabs., 11 refs

  12. Prototype of a Laser-Induced Fluorescence Ground-Based Instrument for Measurements of Atmospheric Iodine Monoxide (IO)

    Science.gov (United States)

    Thurlow, M. E.; Co, D. T.; Hanisco, T. F.; Lapson, L. B.; Anderson, J. G.

    2008-12-01

    High abundances of iodine monoxide (IO) are known to exist and to participate in local photochemistry of the marine boundary layer: (1) IO participates in depletion episodes of O3 and in the removal of mercury in the Arctic polar spring by enhancing atomic Br mixing ratios. Recent observations and computer simulations suggest that mercury sequestration is closely tied to halogen photochemistry and that gaseous atomic Hg depletion can be enhanced significantly by the presence of small amounts of iodine-containing compounds. (2) IO and higher- order iodine oxides are involved in the formation of new particles in coastal marine environments. Studies using smog chamber experiments simulating coastal atmospheric conditions have demonstrated that new particles can form from condensable iodine-containing vapors and that their concentrations over the open ocean are sufficient to influence marine particle formation. (3) IO has also been shown to affect the oxidizing capacity of the troposphere by altering the partitioning of NO2/NO and HO2/HO and by activating chlorine and bromine in sea salt aerosols. In the stratosphere, these same processes can lead to enhanced ozone loss rates. Detailed photochemical models that include iodine photochemistry, however, are hampered by the lack of observational data. The distribution of IO in vertical, horizontal, and temporal coordinates is unknown, so the impact of IO on global photochemistry cannot be predicted. The resolution of these important scientific issues requires an in situ IO instrument. A fully functional nanosecond Nd:YAG-pumped Ti:Sapphire laser system and a prototype IO ground-based instrument have been built in our lab. With the current setup, the laser system was situated 10 m from the field station, and the laser light was coupled via an optical fiber. With the use of highly efficient fluorescence detection optics and photon counting techniques, sensitivities of better than 0.1 ppt in 1 s for IO was achieved in the

  13. Liquid film characterization in horizontal, annular, two-phase, gas-liquid flow using time-resolved laser-induced fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Farias, P.S.C.; Martins, F.J.W.A.; Azevedo, L.F.A. [PUC-Rio, Department of Mechanical Engineering, Rio de Janeiro (Brazil); Sampaio, L.E.B. [LMTA/PGMEC, UFF, Department of Mechanical Engineering, Laboratory of Theoretical and Applied Mechanics, Rio de Janeiro (Brazil); Serfaty, R. [Petrobras R and D Center, Rio de Janeiro (Brazil)

    2012-03-15

    A non-intrusive optical technique was developed to provide time-resolved longitudinal and cross-sectional images of the liquid film in horizontal annular pipe flow of air and water, revealing the interfacial wave behavior. Quantitative information on the liquid film dynamics was extracted from the time-resolved images. The planar laser-induced fluorescence technique was utilized to allow for optical separation of the light emitted by the film from that scattered by the air-water interface. The visualization test section was fabricated from a tube presenting nearly the same refractive index as water, which allowed the visualization of the liquid film at regions very close to the pipe wall. Longitudinal images of the liquid film were captured using a high-frame-rate digital video camera synchronized with a high-repetition-rate laser. An image processing algorithm was developed to automatically detect the position of the air-water interface in each image frame. The thickness of the liquid film was measured at two axial stations in each processed image frame, providing time history records of the film thickness at two different positions. Wave frequency information was obtained by analyzing the time-dependent signals of film thickness for each of the two axial positions recorded. Wave velocities were measured by cross-correlating the amplitude signals from the two axial positions. For the film cross-section observations, two high-speed digital video cameras were used in a stereoscopic arrangement. Comparisons with results from different techniques available in literature indicate that the technique developed presents equivalent accuracy in measuring the liquid film properties. Time-resolved images of longitudinal and cross-section views of the film were recorded, which constitute valuable information provided by the technique implemented. (orig.)

  14. Simultaneous determination of superoxide and hydrogen peroxide in macrophage RAW 264.7 cell extracts by microchip electrophoresis with laser-induced fluorescence detection.

    Science.gov (United States)

    Li, Hongmin; Li, Qingling; Wang, Xu; Xu, Kehua; Chen, Zhenzhen; Gong, Xiaocong; Liu, Xin; Tong, Lili; Tang, Bo

    2009-03-15

    A method for the first time to simultaneously determine superoxide and hydrogen peroxide in macrophage RAW 264.7 cell extracts by microchip electrophoresis with laser-induced fluorescence detection (MCE-LIF) was developed. 2-Chloro-1,3-dibenzothiazolinecyclohexene (DBZTC) and bis(p-methylbenzenesulfonyl) dichlorofluorescein (FS), two probes that can be specifically derivatized by superoxide and hydrogen peroxide, respectively, were synthesized and used. Parameters influencing the derivatization and on-chip separation were optimized. With the use of a HEPES (20 mM, pH 7.4) running buffer, a 50 mm long separation channel, and a separation voltage of 1800 V, baseline separation was achieved within 48 s for the two derivatization products, DBZTC-oxide (DBO) and 2,7-dichlorofluorescein (DCF). The linearity ranges of the method were 0.08-5.0 and 0.02-5.0 microM with detection limits (signal-to-noise ratio = 3) of 10 nM (1.36 amol) and 5.6 nM (0.76 amol) for superoxide and hydrogen peroxide, respectively. The relative standard deviations (RSDs) of migration time and peak area were less than 2.0% and 5.0%, respectively. The recoveries of the cell extract samples spiked with 1.0 microM standard solutions were 96.1% and 93.0% for superoxide and hydrogen peroxide, respectively. With the use of this method, superoxide and hydrogen peroxide in phorbol myristate acetate (PMA)-stimulated macrophage RAW 264.7 cell extracts were found to be 0.78 and 1.14 microM, respectively. The method has paved a way for simultaneously determining two or more reactive oxygen species (ROS) in a biological system with high resolution.

  15. Optical-optical double resonance, laser induced fluorescence, and revision of the signs of the spin-spin constants of the boron carbide (BC) free radical

    Energy Technology Data Exchange (ETDEWEB)

    Sunahori, Fumie X. [Department of Chemistry and Physics, Franklin College, Franklin, Indiana 46131 (United States); Nagarajan, Ramya; Clouthier, Dennis J., E-mail: dclaser@uky.edu [Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055 (United States)

    2015-12-14

    The cold boron carbide free radical (BC X {sup 4}Σ{sup −}) has been produced in a pulsed discharge free jet expansion using a precursor mixture of trimethylborane in high pressure argon. High resolution laser induced fluorescence spectra have been obtained for the B {sup 4}Σ{sup −}–X {sup 4}Σ{sup −} and E {sup 4}Π–X {sup 4}Σ{sup −} band systems of both {sup 11}BC and {sup 10}BC. An optical-optical double resonance (OODR) scheme was implemented to study the finer details of both band systems. This involved pumping a single rotational level of the B state with one laser and then recording the various allowed transitions from the intermediate B state to the final E state with a second laser by monitoring the subsequent E–X ultraviolet fluorescence. In this fashion, we were able to prove unambiguously that, contrary to previous studies, the spin-spin constant λ is negative in the ground state and positive in the B {sup 4}Σ{sup −} excited state. It has been shown that λ″ < 0 is in fact expected based on a semiempirical second order perturbation theory calculation of the magnitude of the spin-spin constant. The OODR spectra have also been used to validate our assignments of the complex and badly overlapped E {sup 4}Π–X {sup 4}Σ{sup −} 0-0 and 1-0 bands of {sup 11}BC. The E–X 0-0 band of {sup 10}BC was found to be severely perturbed. The ground state main electron configuration is …3σ{sup 2}4σ{sup 2}5σ{sup 1}1π{sup 2}2π{sup 0} and the derived bond lengths show that there is a 0.03 Å contraction in the B state, due to the promotion of an electron from the 4σ antibonding orbital to the 5σ bonding orbital. In contrast, the bond length elongates by 0.15 Å in the E state, a result of promoting an electron from the 5σ bonding orbital to the 2π antibonding orbitals.

  16. Laser-Induced Fluorescence Emission (L.I.F.E.): searching for Mars organics with a UV-enhanced PanCam.

    Science.gov (United States)

    Storrie-Lombardi, Michael C; Muller, Jan-Peter; Fisk, Martin R; Cousins, Claire; Sattler, Birgit; Griffiths, Andrew D; Coates, Andrew J

    2009-12-01

    The European Space Agency will launch the ExoMars mission in 2016 with a primary goal of surveying the martian subsurface for evidence of organic material. We have recently investigated the utility of including either a 365 nm light-emitting diode or a 375 nm laser light source in the ExoMars rover panoramic camera (PanCam). Such a modification would make it feasible to monitor rover drill cuttings optically for the fluorescence signatures of aromatic organic molecules and map the distribution of polycyclic aromatic hydrocarbons (PAHs) as a function of depth to the 2 m limit of the ExoMars drill. The technique described requires no sample preparation, does not consume irreplaceable resources, and would allow mission control to prioritize deployment of organic detection experiments that require sample destruction, expenditure of non-replaceable consumables, or both. We report here for the first time laser-induced fluorescence emission (L.I.F.E.) imaging detection limits for anthracene, pyrene, and perylene targets doped onto a Mars analog granular peridotite with a 375 nm Nichia laser diode in optically uncorrected wide-angle mode. Data were collected via the Beagle 2 PanCam backup filter wheel fitted with original blue (440 nm), green (530 nm), and red (670 nm) filters. All three PAH species can be detected with the PanCam green (530 nm) filter. Detection limits in the green band for signal-to-noise ratios (S/N) > 10 are 49 parts per million (ppm) for anthracene, 145 ppm for pyrene, and 20 ppm for perylene. The anthracene detection limit improves to 7 ppm with use of the PanCam blue filter. We discuss soil-dependent detection limit constraints; use of UV excitation with other rover cameras, which provides higher spatial resolution; and the advantages of focused and wide-angle laser modes. Finally, we discuss application of L.I.F.E. techniques at multiple wavelengths for exploration of Mars analog extreme environments on Earth, including Icelandic hydrothermally

  17. Laser-induced fluorescence with an OPO system. Part II: direct determination of lead content in seawater by electrothermal atomization-laser-excited atomic fluorescence (ETA-LEAF).

    Science.gov (United States)

    Le Bihan, A; Lijour, Y; Giamarchi, P; Burel-Deschamps, L; Stephan, L

    2003-03-01

    Fluorescence was induced by coupling a laser with an optical parametric oscillator (OPO) to develop an analytical method for the direct determination of lead content, at ultra-trace level, in seawater by electrothermal atomization-laser-excited atomic fluorescence (ETA-LEAF). The optimization of atomization conditions, laser pulse energy, and mainly temporal parameters allowed us to reach a 3 fg detection limit (0.3 ng L(-1)) despite the low repetition rate of the device. The expected error on predicted concentrations of lead, at trace levels, in seawater was below 15%.

  18. [Analysis of software for identifying spectral line of laser-induced breakdown spectroscopy based on LabVIEW].

    Science.gov (United States)

    Hu, Zhi-yu; Zhang, Lei; Ma, Wei-guang; Yan, Xiao-juan; Li, Zhi-xin; Zhang, Yong-zhi; Wang, Le; Dong, Lei; Yin, Wang-bao; Jia, Suo-tang

    2012-03-01

    Self-designed identifying software for LIBS spectral line was introduced. Being integrated with LabVIEW, the soft ware can smooth spectral lines and pick peaks. The second difference and threshold methods were employed. Characteristic spectrum of several elements matches the NIST database, and realizes automatic spectral line identification and qualitative analysis of the basic composition of sample. This software can analyze spectrum handily and rapidly. It will be a useful tool for LIBS.

  19. Revealing discriminating power of the elements in edible sea salts: Line-intensity correlation analysis from laser-induced plasma emission spectra

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yonghoon, E-mail: yhlee@mokpo.ac.kr [Department of Chemistry, Mokpo National University, Jeonnam 534-729 (Korea, Republic of); Ham, Kyung-Sik [Department of Food Engineering, Mokpo National University, Jeonnam 534-729 (Korea, Republic of); Han, Song-Hee [Division of Maritime Transportation System, Mokpo National Maritime University, Jeonnam 530-729 (Korea, Republic of); Yoo, Jonghyun, E-mail: jyoo@appliedspectra.com [Applied Spectra, Inc., 46665 Fremont Boulevard, Fremont, CA 94538 (United States); Jeong, Sungho [School of Mechatronics, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of)

    2014-11-01

    We have investigated the discriminating power of the elements in edible sea salts using Laser-Induced Breakdown Spectroscopy (LIBS). For the ten different sea salts from South Korea, China, Japan, France, Mexico and New Zealand, LIBS spectra were recorded in the spectral range between 190 and 1040 nm, identifying the presence of Na, Cl, K, Ca, Mg, Li, Sr, Al, Si, Ti, Fe, C, O, N, and H. Intensity correlation analysis of the observed emission lines provided a valuable insight into the discriminating power of the different elements in the sea salts. The correlation analysis suggests that the elements with independent discrimination power can be categorized into three groups; those that represent dissolved ions in seawater (K, Li, and Mg), those that are associated with calcified particles (Ca and Sr), and those that are present in soils contained in the sea salts (Al, Si, Ti, and Fe). Classification models using a few emission lines selected based on the results from intensity correlation analysis and full broadband LIBS spectra were developed based on Principal Component Analysis (PCA) and Partial Least Squares-Discriminant Analysis (PLS-DA) and their performances were compared. Our results indicate that effective combination of a few emission lines can provide a dependable model for discriminating the edible sea salts and the performance is not much degraded from that based on the full broadband spectra. This can be rationalized by the intensity correlation results. - Highlights: • Broadband LIBS spectra of various edible sea salts were obtained. • Intensity correlation of emission lines of the elements in edible sea salts was analyzed. • The elements were categorized into three groups with independent discriminating power. • The effective combination of a few lines can provide dependable classification models.

  20. Correcting for variable laser-target distances of laser-induced breakdown spectroscopy measurements with ChemCam using emission lines of Martian dust spectra

    Energy Technology Data Exchange (ETDEWEB)

    Melikechi, N.; Mezzacappa, A. [Optical Science Center for Applied Research, Delaware State University, Dover, DE (United States); Cousin, A.; Lanza, N.L. [Los Alamos National Laboratory, Los Alamos, NM (United States); Lasue, J. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Clegg, S.M. [Los Alamos National Laboratory, Los Alamos, NM (United States); Berger, G. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Wiens, R.C. [Los Alamos National Laboratory, Los Alamos, NM (United States); Maurice, S. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Tokar, R.L.; Bender, S. [Planetary Science Institute, Flagstaff, AZ (United States); Forni, O. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Breves, E.A.; Dyar, M.D. [Dept. of Astronomy, Mount Holyoke College, South Hadley, MA (United States); Frydenvang, J. [The Niels Bohr Institute, University of Copenhagen, Copenhagen (Denmark); Delapp, D. [Los Alamos National Laboratory, Los Alamos, NM (United States); Gasnault, O. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Newsom, H.; Ollila, A.M. [Earth and Planetary Sciences, University of New Mexico, Alburquerque, NM (United States); Lewin, E. [Institut des Sciences de la Terre, Universite Grenoble l-CNRS, Grenoble (France); and others

    2014-06-01

    As part of the Mars Science Laboratory, the ChemCam instrument acquires remote laser induced breakdown spectra at distances that vary between 1.56 m and 7 m. This variation in distance affects the intensities of the measured LIBS emission lines in non-trivial ways. To determine the behavior of a LIBS emission line with distance, it is necessary to separate the effects of many parameters such as laser energy, laser spot size, target homogeneity, and optical collection efficiency. These parameters may be controlled in a laboratory on Earth but for field applications or in space this is a challenge. In this paper, we show that carefully selected ChemCam LIBS emission lines acquired from the Martian dust can be used to build an internal proxy spectroscopic standard. This in turn, allows for a direct measurement of the effects of the distance of various LIBS emission lines and hence can be used to correct ChemCam LIBS spectra for distance variations. When tested on pre-launch LIBS calibration data acquired under Martian-like conditions and with controlled and well-calibrated targets, this approach yields much improved agreement between targets observed at various distances. This work lays the foundation for future implementation of automated routines to correct ChemCam spectra for differences caused by variable distance. - Highlights: • Selected Martian dust emission lines are used to correct for variable laser-target distances. • The correction model yields improved agreement between targets observed at various distances. • The impact of the model reduces the bias between predicted and actual compositions by as much as 70%. • When implemented, the model will yield spectral corrections for various ChemCam measurements. • This work is a foundation to perform novel stand-off LIBS measurements on Earth and other planets.

  1. Laser-induced Breakdown spectroscopy quantitative analysis method via adaptive analytical line selection and relevance vector machine regression model

    International Nuclear Information System (INIS)

    Yang, Jianhong; Yi, Cancan; Xu, Jinwu; Ma, Xianghong

    2015-01-01

    A new LIBS quantitative analysis method based on analytical line adaptive selection and Relevance Vector Machine (RVM) regression model is proposed. First, a scheme of adaptively selecting analytical line is put forward in order to overcome the drawback of high dependency on a priori knowledge. The candidate analytical lines are automatically selected based on the built-in characteristics of spectral lines, such as spectral intensity, wavelength and width at half height. The analytical lines which will be used as input variables of regression model are determined adaptively according to the samples for both training and testing. Second, an LIBS quantitative analysis method based on RVM is presented. The intensities of analytical lines and the elemental concentrations of certified standard samples are used to train the RVM regression model. The predicted elemental concentration analysis results will be given with a form of confidence interval of probabilistic distribution, which is helpful for evaluating the uncertainness contained in the measured spectra. Chromium concentration analysis experiments of 23 certified standard high-alloy steel samples have been carried out. The multiple correlation coefficient of the prediction was up to 98.85%, and the average relative error of the prediction was 4.01%. The experiment results showed that the proposed LIBS quantitative analysis method achieved better prediction accuracy and better modeling robustness compared with the methods based on partial least squares regression, artificial neural network and standard support vector machine. - Highlights: • Both training and testing samples are considered for analytical lines selection. • The analytical lines are auto-selected based on the built-in characteristics of spectral lines. • The new method can achieve better prediction accuracy and modeling robustness. • Model predictions are given with confidence interval of probabilistic distribution

  2. Investigations of glass structure using fluorescence line narrowing and moleuclar dynamics simulations

    International Nuclear Information System (INIS)

    Weber, M.J.; Brawer, S.A.

    1982-01-01

    The local structure at individual ion sites in simple and multicomponent glasses is simulated using methods of molecular dynamics. Computer simulations of fluoroberyllate glasses predict a range of ion separations and coordination numbers that increases with increasing complexity of the glass composition. This occurs at both glass forming and glass modifying cation sites. Laser-induced fluorescence line-narrowing techniques provide a unique probe of the local environments of selected subsets of ions and are used to measure site to site variations in the electronic energy levels and transition probabilities of rare earth ions. These and additional results from EXAFS, neutron and x-ray diffraction, and NMR experiments are compared with simulated glass structures

  3. Laser Induced Fluorescence Imaging: Searching for Organics from the Dry Valleys of Queen Maud Land Antarctica to the Regolith and Ices of Mars

    Science.gov (United States)

    Storrie-Lombardi, M. C.; Sattler, B.; Muller, J.-P.; Fisk, M.; Cousins, C.; Dartnell, L.

    2009-04-01

    Laser induced fluorescence imaging using excitation in ultraviolet (UV) wavelengths has been proposed as a nondestructive astrobiological rapid survey tool to search for amino and nucleic acids [1], microbial life [2], and polycyclic aromatic hydrocarbons (PAHs) deep in the Mars regolith [3, 4]. However, the technique is easily adapted to search for complex biomolecular targets using longer wavelength sources [5]. Of particular interest is the ability of excitation at 532 nm to detect photosynthetic pigments in cyanobacteria-dominated microbial communities populating the ice of alpine, Arctic, and Antarctic lakes, glaciers, and ice sheets [6-8]. During the months of November and December 2008 we tested the technique as part of an extended international, interdisciplinary field campaign in the Dry Valleys of Schirmacher Oasis and Lake Untersee, Queen Maud Land, Antarctica. In this paper we review our recent laboratory experiments on the use of UV excitation for detection of PAHs doped on Mars analogue soils [9] and chasmo- and epilithic lichen communities within basaltic Iceland lavas. We present for the first time the results of our field experiments conducted during the Tawani 2008 International Antarctic Expedition for in situ detection and quantification of photosynthetic biomass in the ice caps of annual and perennially ice-covered Antarctic lakes. We discuss the advantages of using a nondestructive rapid survey photonic tools such as laser induced fluorescence imaging that can be easily implemented from lander, rover, airborne, or orbital platforms. The techniques presented can be utilized to monitor the microbial potential of large, critical ecosystems on Earth, or to facilitate the remote or manned search for organics and photosynthetic life on any terrestrial planet. References 1. Storrie-Lombardi, M.C., Hug, W.F., McDonald, G.D., Tsapin, A.I., and Nealson, K.H. 2001. Hollow cathode ion lasers for deep ultraviolet Raman spectroscopy and fluorescence imaging

  4. Determination of inorganic nutrients in wheat flour by laser-induced breakdown spectroscopy and energy dispersive X-ray fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Peruchi, Lidiane Cristina; Nunes, Lidiane Cristina; Gustinelli Arantes de Carvalho, Gabriel; Guerra, Marcelo Braga Bueno; Almeida, Eduardo de; Rufini, Iolanda Aparecida [NAPTISA Research Support Center “Technology and Innovation for a Sustainable Agriculture”, Center for Nuclear Energy in Agriculture, University of São Paulo, Av. Centenário 303, 13416-000, Piracicaba SP (Brazil); Santos, Dário [Federal University of São Paulo, R. Prof. Artur Riedel 275, 09972-270, Diadema SP (Brazil); Krug, Francisco José, E-mail: fjkrug@cena.usp.br [NAPTISA Research Support Center “Technology and Innovation for a Sustainable Agriculture”, Center for Nuclear Energy in Agriculture, University of São Paulo, Av. Centenário 303, 13416-000, Piracicaba SP (Brazil)

    2014-10-01

    Laser-induced breakdown spectroscopy (LIBS) and energy dispersive X-ray fluorescence spectrometry (EDXRF) were evaluated for the determination of P, K, Ca, Mg, S, Fe, Cu, Mn and Zn in pressed pellets of wheat flours. EDXRF and LIBS calibration models were built with analytes mass fractions determined by inductively coupled plasma optical emission spectrometry after microwave-assisted acid digestion in a set of 25 wheat flour laboratory samples. Test samples consisted of pressed pellets prepared from wheat flour mixed with 30% mm{sup −1} cellulose binder. Experiments were carried out with a LIBS setup consisted of a Q-switched Nd:YAG laser and a spectrometer with Echelle optics and ICCD, and a benchtop EDXRF system fitted with a Rh target X-ray tube and a Si(Li) semiconductor detector. The correlation coefficients from the linear calibration models of P, K, Ca, Mg, S, Fe, Mn and Zn determined by LIBS and/or EDXRF varied from 0.9705 for Zn to 0.9990 for Mg by LIBS, and from 0.9306 for S to 0.9974 for K by EDXRF. The coefficients of variation of measurements varied from 1.2 to 20% for LIBS, and from 0.3 to 24% for EDXRF. The predictive capabilities based on RMSEP (root mean square error of prediction) values were appropriate for the determination of P, Ca, Mg, Fe, Mn and Zn by LIBS, and for P, K, S, Ca, Fe, and Zn by EDXRF. In general, results from the analysis of NIST SRM 1567a Wheat flour by LIBS and EDXRF were in agreement with their certified mass fractions. - Highlights: • Combination of LIBS and EDXRF for quantitative analysis of wheat flour. • Validation performed for determination of P, K, Ca, Mg, S, Fe, Cu, Mn and Zn. • Same test samples can be used for both methods. • Appropriate limits of detection for all tested analytes. • Methods are simple and provide fast and accurate results for routine analysis.

  5. 2D and 3D imaging of the gas phase close to an operating model catalyst by planar laser induced fluorescence

    International Nuclear Information System (INIS)

    Blomberg, Sara; Gustafson, Johan; Lundgren, Edvin; Zhou, Jianfeng; Zetterberg, Johan

    2016-01-01

    In recent years, efforts have been made in catalysis related surface science studies to explore the possibilities to perform experiments at conditions closer to those of a technical catalyst, in particular at increased pressures. Techniques such as high pressure scanning tunneling/atomic force microscopy (HPSTM/AFM), near ambient pressure x-ray photoemission spectroscopy (NAPXPS), surface x-ray diffraction (SXRD) and polarization-modulation infrared reflection absorption spectroscopy (PM-IRAS) at semi-realistic conditions have been used to study the surface structure of model catalysts under reaction conditions, combined with simultaneous mass spectrometry (MS). These studies have provided an increased understanding of the surface dynamics and the structure of the active phase of surfaces and nano particles as a reaction occurs, providing novel information on the structure/activity relationship. However, the surface structure detected during the reaction is sensitive to the composition of the gas phase close to the catalyst surface. Therefore, the catalytic activity of the sample itself will act as a gas-source or gas-sink, and will affect the surface structure, which in turn may complicate the assignment of the active phase. For this reason, we have applied planar laser induced fluorescence (PLIF) to the gas phase in the vicinity of an active model catalysts. Our measurements demonstrate that the gas composition differs significantly close to the catalyst and at the position of the MS, which indeed should have a profound effect on the surface structure. However, PLIF applied to catalytic reactions presents several beneficial properties in addition to investigate the effect of the catalyst on the effective gas composition close to the model catalyst. The high spatial and temporal resolution of PLIF provides a unique tool to visualize the on-set of catalytic reactions and to compare different model catalysts in the same reactive environment. The technique can be

  6. Atmospheric measurements of OH, HO2 and NO by laser-induced fluorescence spectroscopy using a compact all solid-state laser system

    Science.gov (United States)

    Bloss, W. J.; Floquet, C.; Gravestock, T. J.; Heard, D. E.; Ingham, T.; Johnson, G. P.; Lee, J. D.

    2003-04-01

    Free-radicals are key intermediates that control the budgets of many trace gases, for example ozone, greenhouse gases and harmful pollutants. Measurement of radicals and comparison with model calculations constitutes an important test of our understanding of the underlying chemistry. There is a greater need for compact and lightweight instruments for the in situ measurement of free-radical species that are suitable for deployment from a number of field-platforms. A new field instrument has been developed that incorporates an all solid-state Nd:YAG pumped titanium sapphire laser that is capable of generating radiation at high pulse-repetition-frequency for the detection of OH, HO_2, NO and IO radicals in the atmosphere by laser induced fluorescence (LIF). The system offers advantages of wide wavelength tunability, compactness, low weight, greater long-term stability (fibre-optic delivery) and short warm-up time. The instrument was successfully deployed during 2002 in the NAMBLEX field campaign at Mace Head with detection limits for OH and HO_2 (measured simultaneously with laser operation at 308 nm) of 3.1 x 10^5 molecule cm-3 (0.012 ppt) and 2.6 x 10^6 molecule cm-3 (0.09 pptv) respectively. Diurnal profiles of OH have been recorded over a period of 5 weeks. NO controls the HO_2/OH ratio and is the critical parameter in the production of tropospheric ozone, yet measurements in the boundary layer are restricted to a single indirect technique based on chemiluminescent analysers. Measurements of NO in the atmosphere have been made by LIF using the new instrument operating at 226 nm, with absolute concentrations in good agreement with simultaneous measurements made using a commercial chemiluminescent analyser. Whilst operating at 445 nm, the instrument has detected the IO radical in the laboratory, with a projected detection limit that is well below previously measured atmospheric concentrations of IO. A second instrument to be deployed on an aircraft platform is

  7. 2D and 3D imaging of the gas phase close to an operating model catalyst by planar laser induced fluorescence

    Science.gov (United States)

    Blomberg, Sara; Zhou, Jianfeng; Gustafson, Johan; Zetterberg, Johan; Lundgren, Edvin

    2016-11-01

    In recent years, efforts have been made in catalysis related surface science studies to explore the possibilities to perform experiments at conditions closer to those of a technical catalyst, in particular at increased pressures. Techniques such as high pressure scanning tunneling/atomic force microscopy (HPSTM/AFM), near ambient pressure x-ray photoemission spectroscopy (NAPXPS), surface x-ray diffraction (SXRD) and polarization-modulation infrared reflection absorption spectroscopy (PM-IRAS) at semi-realistic conditions have been used to study the surface structure of model catalysts under reaction conditions, combined with simultaneous mass spectrometry (MS). These studies have provided an increased understanding of the surface dynamics and the structure of the active phase of surfaces and nano particles as a reaction occurs, providing novel information on the structure/activity relationship. However, the surface structure detected during the reaction is sensitive to the composition of the gas phase close to the catalyst surface. Therefore, the catalytic activity of the sample itself will act as a gas-source or gas-sink, and will affect the surface structure, which in turn may complicate the assignment of the active phase. For this reason, we have applied planar laser induced fluorescence (PLIF) to the gas phase in the vicinity of an active model catalysts. Our measurements demonstrate that the gas composition differs significantly close to the catalyst and at the position of the MS, which indeed should have a profound effect on the surface structure. However, PLIF applied to catalytic reactions presents several beneficial properties in addition to investigate the effect of the catalyst on the effective gas composition close to the model catalyst. The high spatial and temporal resolution of PLIF provides a unique tool to visualize the on-set of catalytic reactions and to compare different model catalysts in the same reactive environment. The technique can be

  8. Profiling an electrospray plume by laser-induced fluorescence and Fraunhofer diffraction combined to mass spectrometry: influence of size and composition of droplets on charge-state distributions of electrosprayed proteins.

    Science.gov (United States)

    Girod, Marion; Dagany, Xavier; Boutou, Véronique; Broyer, Michel; Antoine, Rodolphe; Dugourd, Philippe; Mordehai, Alex; Love, Craig; Werlich, Mark; Fjeldsted, John; Stafford, George

    2012-07-14

    We investigated how physico-chemical properties of charged droplets are affected by the electrospray process, using simultaneous in situ measurements by laser-induced fluorescence (LIF), Fraunhofer diffraction and mass spectrometry. For this purpose, we implemented a laser-induced-fluorescence profiling setup in conjunction with a fast, high-resolution particle sizing scheme on a modified Agilent Jet Stream electrospray source coupled to a single quadrupole mass analyser. The optical setup permits us to profile the solvent fractionation and the size of the droplets as they evaporate in an electrospray plume by measuring both the angular scattering pattern and emission spectra of a solvatochromic fluorescent dye. Mass spectra are recorded simultaneously. These mass spectrometry and optical spectroscopy investigations allow us to study the relation between the observed charge-state distributions of protein anions and physico-chemical properties of evaporating droplets in the spray plume. By mixing water with methanol, a refolding of cytochrome C is observed as the water percentage increases in the plume due to the preponderant evaporation of volatile methanol.

  9. Direct determination of Ti content in sunscreens with laser-induced breakdown spectroscopy: Line selection method for high TiO{sub 2} nanoparticle concentration

    Energy Technology Data Exchange (ETDEWEB)

    Menneveux, Jérôme; Wang, Fang; Lu, Shan; Bai, Xueshi; Motto-Ros, Vincent [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne Cedex (France); Gilon, Nicole [Institut des Sciences Analytiques, UMR5280 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne Cedex (France); Chen, Yanping [Department of Physics and Astrophysics, Shanghai Jiao Tong University, Shanghai 200240 (China); Yu, Jin, E-mail: jin.yu@univ-lyon1.fr [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne Cedex (France); Department of Physics and Astrophysics, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2015-07-01

    Sunscreen represents a large variety of creams which, in the analytical point of view, exhibit a similar matrix. Such matrix corresponds to a semi-solid emulsion of mixture of oil and water. The formulation of a cream can include metal and nonmetal elements in different contents in order to realize specific pharmaceutical or cosmetic functions designed for the product. The complex matrix of these materials makes their analysis challenging for classical elemental analytical techniques with specific and complicated sample pretreatment procedures needed for reliable quantification. In this work we demonstrate and assess direct determination, without any pretreatment, of elemental content, especially for metallic element such as titanium, in a sunscreen using laser-induced breakdown spectroscopy (LIBS). The used configuration corresponds to that of indirect ablation of a thin film of cream applied on the surface of a pure aluminum target. We especially focused, in this work, on the case of high concentration of TiO{sub 2} nanoparticle in cream. Such choice was justified first by the fact that such concentration level is usually found in commercial sunscreens. On the other hand, titanium presents a large number of lines, neutral as well as singly ionized, in the spectral range from the near UV to the near IR. It provides therefore an ideal case to study line selection method to manage the effect of self-absorption, which becomes unavoidable at high concentration level, and to optimize measurement precision. Through such study, we try to deduce a quantifiable and generalizable line selection method for high performance LIBS measurements. More specifically, calibration curves were first established using 6 laboratory-prepared samples. The quadratic term of the curves was then studied as a function of the intensity of the used lines and their type (neutral or ion, resonant or non-resonant). The prediction performance of the lines was assessed with 2 validation samples with

  10. On-line/on-site analysis of heavy metals in water and soils by laser induced breakdown spectroscopy

    Science.gov (United States)

    Meng, Deshuo; Zhao, Nanjing; Wang, Yuanyuan; Ma, Mingjun; Fang, Li; Gu, Yanhong; Jia, Yao; Liu, Jianguo

    2017-11-01

    The enrichment method of heavy metal in water with graphite and aluminum electrode was studied, and combined with plasma restraint device for improving the sensitivity of detection and reducing the limit of detection (LOD) of elements. For aluminum electrode enrichment, the LODs of Cd, Pb and Ni can be as low as several ppb. For graphite enrichment, the measurement time can be less than 3 min. The results showed that the graphite enrichment and aluminum electrode enrichment method can effectively improve the LIBS detection ability. The graphite enrichment method combined with plasma spatial confinement is more suitable for on-line monitoring of industrial waste water, the aluminum electrode enrichment method can be used for trace heavy metal detection in water. A LIBS method and device for soil heavy metals analysis was also developed, and a mobile LIBS system was tested in outfield. The measurement results deduced from LIBS and ICP-MS had a good consistency. The results provided an important application support for rapid and on-site monitoring of heavy metals in soil. (Left: the mobile LIBS system for analysis of heavy metals in soils. Top right: the spatial confinement device. Bottom right: automatic graphite enrichment device for on0line analysis of heavy metals in water).

  11. Microchip capillary electrophoresis with laser-induced fluorescence combined with one-step duplex reverse-transcription polymerase chain reaction for the rapid detection of Enterovirus 71 and Coxsackievirus A16 in throat swab specimens.

    Science.gov (United States)

    Jia, Ruan; Chengjun, Sun; Heng, Chen; Chen, Zhou; Yuanqian, Li; Yongxin, Li

    2015-07-01

    Enterovirus 71 and Coxsackievirus A16 are the main pathogens causing hand-foot-mouth disease. In this paper, microchip capillary electrophoresis with laser-induced fluorescence combined with one-step duplex reverse transcript-polymerase chain reaction has been developed for the detection of Enterovirus 71 and Coxsackievirus A16 in throat swab specimens. The specific reverse transcription-polymerase chain reaction amplicons labeled with SYBR Orange were separated by microchip capillary electrophoresis and detected by laser induced fluorescence detector within 7 min. The intraday and interday relative standard deviation of migration time for DNA Marker was in the range of 1.36-2.94 and 2.78-3.96%, respectively. The detection limits were as low as 2.06 × 10(3) copies/mL for Enterovirus 71 and 5 × 10(3) copies/mL for Coxsackievirus A16. No cross-reactivity was observed with rotavirus, astrovirus, norovirus, and adenovirus, which showed good specificity of the method. This assay was validated using 100 throat swab specimens that were detected by real-time reverse-transcript polymerase chain reaction in parallel and the two methods produced the same results. This study provided a rapid, sensitive and specific method for the detection of Enterovirus 71 and Coxsackievirus A16, which make a contribution to significant time and cost saving for the identification and treatment of patients. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Chemical analysis of industrial scale deposits by combined use of correlation coefficients with emission line detection of laser induced breakdown spectroscopy spectra

    International Nuclear Information System (INIS)

    Siozos, P.; Philippidis, A.; Hadjistefanou, M.; Gounarakis, C.; Anglos, D.

    2013-01-01

    Laser-induced breakdown spectroscopy (LIBS) was used to determine the mineral composition of various industrial scale samples. The aim of the study has been to investigate the capacity of LIBS to provide a fast, reliable analytical tool for carrying out routine analysis of inorganic scales, potentially on site, as a means to facilitate decision making concerning scale removal procedures. LIBS spectra collected in the range of 200–660 nm conveyed information about the metal content of the minerals. Via a straightforward analysis based on linear correlation of LIBS spectra it was possible to successfully discriminate scale samples into three main groups, Fe-rich, Ca-rich and Ba-rich, on the basis of correlation coefficients. By combining correlation coefficients with spectral data collected in the NIR, 860–960 nm, where sulfur emissions are detected, it became further possible to discriminate sulfates from carbonates as confirmed by independent analysis based on Raman spectroscopy. It is emphasized that the proposed LIBS-based method successfully identifies the major mineral or minerals present in the samples classifying the scales into relevant groups hence enabling process engineers to select appropriate scale dissolution strategies. - Highlights: • LIBS was used to determine the mineral composition of industrial scale samples. • Three groups of inorganic scales were identified: Ca rich, Ba rich and Fe rich. • A method that combines correlation coefficients and line detection is proposed. • The method successfully identifies the main mineral, or minerals, in the samples. • The results were compared with results obtained by use of Raman analysis

  13. Determination of the D/T fuel mixture using two-photon laser induced fluorescence in combination with neutral beam injection

    International Nuclear Information System (INIS)

    Voslamber, D.; Mandl, W.

    1997-08-01

    Doppler-free two-photon induced fluorescence in the Lyman-α lines of H, D and T has been suggested previously as a local and isotope-selective diagnostic of the intrinsic neutral hydrogen densities in magnetically confined fusion plasmas. In the present paper it is shown that the diagnostic potential of this method is significantly increased if it is combined with neutral atom beams whose characteristics are such that efficient production of thermal ground state atoms via charge exchange reactions is achieved. Considerably deeper plasma regions than just the plasma edge can thus be probed and local, isotope-selective information is obtained on the more relevant ions rather than on the neutrals. Additional diagnostic possibilities, e.g. those arising from the spectroscopic investigation of the beam particles themselves, are also discussed. (author)

  14. Application of the laser induced fluorescence to the investigation of highly magnetized plasmas, heated by ion cyclotron resonance; Fluorescence induite par laser sur des plasmas fortement magnetises, chauffes par resonnance cyclotron ionique

    Energy Technology Data Exchange (ETDEWEB)

    Pailloux, A. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. des Procedes d`Enrichissement]|[Universite Louis Pasteur, 67 - Strasbourg (France)

    1997-12-31

    This work has been achieved in the frame of isotopic separation studies by in cyclotron resonance. For this purpose, in a highly magnetized (2 to 3 Tesla) and non-collisional (10{sup 12} ions/cm{sup 3}) plasma, composed of metallic ions, a wave near the ion cyclotron frequency is thrown in order to heat selectively a given species. A laser induced fluorescence (LIP) has been developed on barium and gadolinium plasmas. The Larmor gyration of ions greatly modifies the interaction, which has been modelled through the time-dependent Schroedinger equation. The obtained excitation probably has been integrated over all the ions excited in the measurement volume in order to check that the LIF still leads to the distribution function of ion velocities. The influence of the Larmor motion of ions on the spectral distribution of LIF has been derived both theoretically and experimentally. The LIF diagnostics has been achieved with a dye O`ring laser. The barium ion has been excited on the transition 6142 angstrom, using rhodamine 6G dye, and the gadolinium ion on the pseudo-triplet 3861 angstrom, using exalite dye. Data treatment has been developed taking into account the Zeeman effect and the different heating of isotopes. The ionic temperature (from 1 eV to some hundreds eV) has been measured as a function of radiofrequency heating. Our experimental results are in good agreement with the selective heating theory. Also, the ion velocity distribution function has been found locally Maxwellian. And the behaviour of the plasma has been studied as a function of control parameters of the plasma source. (author) 62 refs.

  15. Oxygen imaging at the sediment-water interface using lifetime-based laser induced fluorescence (tau LIF) of nano-sized particles

    DEFF Research Database (Denmark)

    Murniati, E.; Gross, D.; Herlina, H.

    2016-01-01

    Most applications of laser induced fluorescence (LIF) for dissolved oxygen (DO) imaging in flowing water are based on luminescence intensity measurements of a dissolved indicator. A major limitation for applying the technique in the bottom boundary layer (BBL) is the sorption of the luminescent dye...... to organic surfaces at the sediment. Many sediment and soil studies have used planar optodes on transparent foils as an imaging technique for observing concentration distributions across the sediment-water interface. The presence of the foil, however, is restricting the free flow and therewith the DO...

  16. Conformational studies of the (+)-trans, (-)-trans, (+)-cis, and (-)-cis adducts of anti-benzo[a]pyrene diolepoxide to N2-dG in duplex oligonucleotides using polyacrylamide gel electrophoresis and low-temperature fluorescence spectroscopy

    NARCIS (Netherlands)

    Suh, Myungkoo; Ariese, Freek; Small, Gerald J.; Jankowiak, Ryszard; Liu, Tong Ming; Geacintov, Nicholas E.

    1995-01-01

    Using polyacrylamide gel electrophoresis (PAGE) and low-temperature, laser-induced fluorescence line narrowing (FLN) and non-line narrowing (NLN) spectroscopic methods, the conformational characteristics of stereochemically defined and site-specific adducts derived from the binding of

  17. Application of thermal-dissociation laser induced fluorescence (TD-LIF to measurement of HNO3, Σalkyl nitrates, Σperoxy nitrates, and NO2 fluxes using eddy covariance

    Directory of Open Access Journals (Sweden)

    D. K. Farmer

    2006-01-01

    Full Text Available Nitrogen exchange between the atmosphere and biosphere directly influences atmospheric composition. While much is known about mechanisms of NO and N2O emissions, instrumentation for the study of mechanisms contributing to exchange of other major nitrogen species is quite limited. Here we describe the application of a new technique, thermal dissociation-laser induced fluorescence (TD-LIF, to eddy covariance measurements of the fluxes of NO2, total peroxy acyl and peroxy nitrates, total alkyl and multifunctional alkyl nitrates, and nitric acid. The technique offers the potential for investigating mechanisms of exchange of these species at the canopy scale over timescales from days to years. Examples of flux measurements at a ponderosa pine plantation in the mid-elevation Sierra Nevada Mountains in California are reported and used to evaluate instrument performance.

  18. Setting-up of the Laser Induced Fluorescence diagnostic. Measurements of Cr density in a neon glow discharge; Puesta a punto del diagnstico de fluorescencia inducida por laser. Medidas de densidad de Cr en Glow discharg de Neon

    Energy Technology Data Exchange (ETDEWEB)

    Tafalla, D.; Cal, E. de la; Tabares, F. L.

    1994-07-01

    A plasma diagnostic based on the Laser Induced Fluorescence (LIF) technique has been set up in the Fusion Division at the CIEMAT. In a preliminary experiment, the density of sputtered chromium atoms produced in a neon glow discharge was measured. Firstly, the laser beam was characterized by calibration of its wavelength, bandwidth and energy profile and Rayleigh scattering in N2 was used for the optical system calibration. An absolute density of Cr atoms of n {approx} 5x10 cm was obtained in discharges at 100 mA and pressure of 15 mTorr and a linear dependence of the LIF signal us. current was found. These values are in agreement with those expected from the tabulated sputtering yields and the thermalization and diffusion of the sputtered atoms into the Ne plasma. (Author) 19 refs.

  19. Time resolved laser induced fluorescence on argon intermediate pressure microwave discharges: Measuring the depopulation rates of the 4p and 5p excited levels as induced by electron and atom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Palomares, J.M., E-mail: j.m.palomares-linares@tue.nl; Graef, W.A.A.D.; Hübner, S.; Mullen, J.J.A.M. van der, E-mail: jjamvandermullen@gmail.com

    2013-10-01

    The reaction kinetics in the excitation space of Ar is explored by means of Laser Induced Fluorescence (LIF) experiments using the combination of high rep-rate YAG–Dye laser systems with a well defined and easily controllable surfatron induced plasma setup. The high rep-rate favors the photon statistics while the low energy per pulse avoids intrusive plasma laser interactions. An analysis shows that, despite the low energy per pulse, saturation can still be achieved even when the geometrical overlap and spectral overlap are optimal. Out of the various studies that can be performed with this setup we confine the current paper to the study of the direct responses to the laser pump action of three 4p and one 5p levels of the Ar system. By changing the plasma in a controlled way one gets for these levels the rates of electron and atom quenching and therewith the total destruction rates of electron and atom collisions. Comparison with literature shows that the classical hard sphere collision rate derived for hydrogen gives a good description for the observed electron quenching (e-quenching) in Ar whereas for heavy particle quenching (a-quenching) this agreement was only found for the 5p level. An important parameter in the study of electron excitation kinetics is the location of the boundary in the atomic system for which the number of electron collisions per radiative life time equals unity. It is observed that for the Ar system this boundary is positioned lower than what is expected on grounds of H-like formulas. - Highlights: • Time resolved laser induced fluorescence at high repetition rate • Decay times as function of pressure, electron density and temperature • Measurement of total electron atom depopulation rates • Reasonable agreement of electron total rates with hard sphere approximations.

  20. Fluorescence line-narrowing studies of Nd:glass laser materials

    International Nuclear Information System (INIS)

    Riseberg, L.A.; Brecher, C.

    The increasing importance of Nd glass lasers in laser fusion technology has emphasized the inadequacy in the understanding of the optical properties of rare earth ions in glasses. Indeed, it has been difficult to generate models for the performance of these devices, and the selection of host glasses could be done by little more than a trial-and-error approach. The technique of laser-induced fluorescence line-narrowing developed within the last few years provides a new and powerful tool for the study of these systems. In this technique, a laser excites within the inhomogeneously broadened absorption bands a selected subgroup of the ions in the system, namely those whose absorption energy is resonant with the laser. If the excitation does not migrate among the entire collection of ions prior to fluorescence, the fluorescence that is observed is only from the group that was excited and is narrowed. This permits the selective study of classes of ion sites within the ensemble. The concept is indicated schematically. By the use of a tunable laser, such as a dye laser, it is possible to vary the class of sites, defined by energy, that is excited and thereby study the important spectroscopic properties and their variations, unclouded by the averaging that occurs under excitation of the entire system. Furthermore, it is then possible to use the spectroscopic information to infer a description of the variation of the microscopic environment, and a rationalization of the effects of compositional changes. Use of a pulsed dye laser and time-resolved detection permits the study of the dynamics, including, for example, the energy transfer among ions of different energies within the inhomogeneously-broadened spectrum. The goal of this project has been to apply such studies to glasses of interest to glass laser technology, providing information for device modeling, and establishing design criteria for glass selection

  1. Laser induced photochemical and photophysical processes in fuel reprocessing: present scenario and future prospects

    International Nuclear Information System (INIS)

    Bhowmick, G.K.; Sarkar, S.K.; Ramanujam, A.

    2001-01-01

    State-of-art lasers can meet the very stringent requirements of nuclear technology and hence find application in varied areas of nuclear fuel cycle. Here, we discuss two specific applications in nuclear fuel reprocessing namely (a) add-on photochemical modifications of PUREX process where photochemical reactors replace the chemical reactors, and (b) fast, matrix independent sensitive laser analytical techniques. The photochemical modifications based on laser induced valency adjustment offers efficient separation, easy maintenance and over all reduction in the volume of radioactive waste. The analytical technique of time resolved laser induced fluorescence (TRLIF) has several attractive features like excellent sensitivity, element selective, and capability of on line remote process monitoring. For optically opaque solutions, optical excitation is detected by its conversion into thermal energy by non-radiative relaxation processes using the photo-thermal spectroscopic techniques. (author)

  2. Europium Uptake and Partitioning in Oat (Avena sativa) Roots as studied By Laser-Induced Fluorescence Spectroscopy and Confocal Microscopy Profiling Technique

    International Nuclear Information System (INIS)

    Fellows, Robert J.; Wang, Zheming; Ainsworth, Calvin C.

    2003-01-01

    The uptake of Eu3+ by elongating oat plant roots was studied by fluorescence spectroscopy, fluorescence lifetime measurement, as well as laser excitation time-resolved confocal fluorescence profiling technique. The results of this work indicated that the initial uptake of Eu(III) by oat root was most evident within the apical meristem of the root just proximal to the root cap. Distribution of assimilated Eu(III) within the roots differentiation and elongation zone was non-uniform. Higher concentrations were observed within the vascular cylinder, specifically in the phloem and developing xylem parenchyma. Elevated levels of the metal were also observed in the root hairs of the mature root. The concentration of assimilated Eu3+ dropped sharply from the apical meristem to the differentiation and elongation zone and then gradually decreased as the distance from the root cap increased. Fluorescence spectroscopic characteristics of the assimilated Eu3+ suggested that the Eu3+ exists a s inner-sphere mononuclear complexes inside the root. This work has also demonstrated the effectiveness of a time-resolved Eu3+ fluorescence spectroscopy and confocal fluorescence profiling techniques for the in vivo, real-time study of metal[Eu3+] accumulation by a functioning intact plant root. This approach can prove valuable for basic and applied studies in plant nutrition and environmental uptake of actinide radionuclides

  3. Laser induced energy transfer

    International Nuclear Information System (INIS)

    Falcone, R.W.

    1979-01-01

    Two related methods of rapidly transferring stored energy from one excited chemical species to another are described. The first of these, called a laser induced collision, involves a reaction in which the energy balance is met by photons from an intense laser beam. A collision cross section of ca 10 - 17 cm 2 was induced in an experiment which demonstrated the predicted dependence of the cross section on wavelength and power density of the applied laser. A second type of laser induced energy transfer involves the inelastic scattering of laser radiation from energetically excited atoms, and subsequent absorption of the scattered light by a second species. The technique of producing the light, ''anti-Stokes Raman'' scattering of visible and infrared wavelength laser photons, is shown to be an efficient source of narrow bandwidth, high brightness, tunable radiation at vacuum ultraviolet wavelengths by using it to excite a rare gas transition at 583.7 A. In addition, this light source was used to make the first measurement of the isotopic shift of the helium metastable level at 601 A. Applications in laser controlled chemistry and spectroscopy, and proposals for new types of lasers using these two energy transfer methods are discussed

  4. Spatially resolved analyses of uranium species using a coupled system made up of confocal laser-scanning microscopy (CLSM) and laser induced fluorescence spectroscopy (LIFS); Ortsaufgeloeste Analyse von Uranspezies mittels einem Gekoppelten System aus Konfokaler Laser-Scanning Mikroskopie (CLSM) und Laser Induzierter Fluoreszenzspektroskopie (LIFS)

    Energy Technology Data Exchange (ETDEWEB)

    Brockmann, S. [Verein fuer Kernverfahrenstechnik und Analytik Rossendorf e.V. (VKTA), Dresden (Germany); Grossmann, K.; Arnold, T. [Helmholtz-Zentrum Dresden-Rossendorf e.V. (Germany). Inst. fuer Ressourcenoekologie

    2014-01-15

    The fluorescent properties of uranium when excited by UV light are used increasingly for spectroscope analyses of uranium species within watery samples. Here, alongside the fluorescent properties of the hexavalent oxidation phases, the tetra and pentavalent oxidation phases also play an increasingly important role. The detection of fluorescent emission spectrums on solid and biological samples using (time-resolved) laser induced fluorescence spectroscopy (TRLFS or LIFS respectively) has, however, the disadvantage that no statements regarding the spatial localisation of the uranium can be made. However, particularly in complex, biological samples, such statements on the localisation of the uranium enrichment in the sample are desired, in order to e.g. be able to distinguish between intra and extra-cellular uranium bonds. The fluorescent properties of uranium (VI) compounds and minerals can also be used to detect their localisation within complex samples. So the application of fluorescent microscopic methods represents one possibility to localise and visualise uranium precipitates and enrichments in biological samples, such as biofilms or cells. The confocal laser-scanning microscopy (CLSM) is especially well suited to this purpose. Coupling confocal laser-scanning microscopy (CLSM) with laser induced fluorescence spectroscopy (LIFS) makes it possible to localise and visualise fluorescent signals spatially and three-dimensionally, while at the same time being able to detect spatially resolved, fluorescent-spectroscopic data. This technology is characterised by relatively low detection limits from up to 1.10{sup -6} M for uranium (VI) compounds within the confocal volume. (orig.)

  5. Spectrophotometry of Bowen resonance fluorescence lines in three planetary nebulae

    Science.gov (United States)

    O'Dell, C. R.; Miller, Christopher O.

    1992-01-01

    The results are presented of a uniquely complete, carefully reduced set of observations of the O III Bowen fluorescence lines in the planetary nebulae NGC 6210, NGC 7027, and NGC 7662. A detailed comparison with the predictions of radiative excitation verify that some secondary lines are enhanced by selective population by the charge exchange mechanism involving O IV. Charge exchange is most important in NGC 6210, which is of significantly lower ionization than the other nebulae. In addition to the principal Bowen lines arising from Ly-alpha pumping of the O III O1 line, lines arising from pumping of the O3 line are also observed. Comparison of lines produced by O1 and O3 with the theoretical predictions of Neufeld indicate poor agreement; comparison with the theoretical predictions of Harrington show agreement with NGC 7027 and NGC 7662.

  6. Snapshot imaging Fraunhofer line discriminator for detection of plant fluorescence

    Science.gov (United States)

    Gupta Roy, S.; Kudenov, M. W.

    2015-05-01

    Non-invasive quantification of plant health is traditionally accomplished using reflectance based metrics, such as the normalized difference vegetative index (NDVI). However, measuring plant fluorescence (both active and passive) to determine photochemistry of plants has gained importance. Due to better cost efficiency, lower power requirements, and simpler scanning synchronization, detecting passive fluorescence is preferred over active fluorescence. In this paper, we propose a high speed imaging approach for measuring passive plant fluorescence, within the hydrogen alpha Fraunhofer line at ~656 nm, using a Snapshot Imaging Fraunhofer Line Discriminator (SIFOLD). For the first time, the advantage of snapshot imaging for high throughput Fraunhofer Line Discrimination (FLD) is cultivated by our system, which is based on a multiple-image Fourier transform spectrometer and a spatial heterodyne interferometer (SHI). The SHI is a Sagnac interferometer, which is dispersion compensated using blazed diffraction gratings. We present data and techniques for calibrating the SIFOLD to any particular wavelength. This technique can be applied to quantify plant fluorescence at low cost and reduced complexity of data collection.

  7. Cascade generation in Al laser induced plasma

    Science.gov (United States)

    Nagli, Lev; Gaft, Michael; Raichlin, Yosef; Gornushkin, Igor

    2018-05-01

    We found cascade IR generation in Al laser induced plasma. This generation includes doublet transitions 3s 25s 2S1/2 → 3s24p 2P1/2,3/2 → 3s24s 2S1/2; corresponding to strong lines at 2110 and 2117 nm, and much weaker lines at 1312-1315 nm. The 3s25s2S 1/2 starting IR generation level is directly pumped from the 3s23p 2P3/2 ground level. The starting level for UV generation at 396.2 nm (transitions 3s24s 2S1/2 → 4p 2P3/2) is populated due to the fast collisional processes in the plasma plume. These differences led to different time and special dependences on the lasing in the IR and UV spectral range within the aluminum laser induced plasma.

  8. Simultaneous determination of reactive oxygen and nitrogen species in mitochondrial compartments of apoptotic HepG2 cells and PC12 cells based on microchip electrophoresis-laser-induced fluorescence.

    Science.gov (United States)

    Chen, Zhenzhen; Li, Qingling; Sun, Qianqian; Chen, Hao; Wang, Xu; Li, Na; Yin, Miao; Xie, Yanxia; Li, Hongmin; Tang, Bo

    2012-06-05

    Determination of intracellular bioactive species will afford beneficial information related to cell metabolism, signal transduction, cell function, and disease treatment. In this study, the first application of a microchip electrophoresis-laser-induced fluorescence (MCE-LIF) method for concurrent determination of reactive oxygen species (ROS) and reactive nitrogen species (RNS), i.e., superoxide (O(2)(-•)) and nitric oxide (NO) in mitochondria, was developed using fluorescent probes 2-chloro-1,3-dibenzothiazolinecyclohexene (DBZTC) and 3-amino,4-aminomethyl-2',7'-difluorescein (DAF-FM), respectively. Potential interference of intracellular dehydroascorbic acid (DHA) and ascorbic acid (AA) for NO detection with DAF-FM was eliminated through oxidation of AA with the addition of ascorbate oxidase, followed by subsequent MCE separation. Fluorescent products of O(2)(-•) and NO, DBZTC oxide (DBO), and DAF-FM triazole (DAF-FMT) showed excellent baseline separation within 1 min with a running buffer of 40 mM Tris solution (pH 7.4) and a separating electric field of 500 V/cm. The levels of DBO and DAF-FMT in mitochondria isolated from normal HepG2 cells and PC12 cells were evaluated using this method. Furthermore, the changes of DBO and DAF-FMT levels in mitochondria isolated from apoptotic HepG2 cells and PC12 cells could also be detected. The current approach was proved to be simple, fast, reproducible, and efficient. Measurement of the two species with the method will be beneficial to understand ROS/RNS distinctive functions. In addition, it will provide new insights into the role that both species play in biological systems.

  9. Turbulent Non-Premixed Flames Stabilized on Double-Slit Curved Wall-Jet Burner with Simultaneous OH-Planar Laser-Induced Fluorescence and Particle Image Velocimetry Measurements

    KAUST Repository

    Mansour, Morkous S.

    2015-04-29

    A double-slit curved wall-jet (CWJ) burner utilizing a Coanda effect by supplying fuel and air as annular-inward jets over a curved surface was employed to investigate the stabilization characteristics and structure of propane/air turbulent non-premixed flames with varying global equivalence ratio and Reynolds number. Simultaneous time-resolved measurements of particle image velocimetry (PIV) and planar laser-induced fluorescence (PLIF) of OH radicals were conducted. The burner showed a potential of stable and non-sooting operation for relatively large fuel loading and overall rich conditions. Mixing characteristics in cold flow were first examined using an acetone fluorescence technique, indicating substantial transport between the fuel and air by exhibiting appreciable premixing conditions. PIV measurements revealed that the flow field consisted of a wall-jet region leading to a recirculation zone through flow separation, an interaction jet region resulting from the collision of annular-inward jets, followed by a merged-jet region. The flames were stabilized in the recirculation zone and, in extreme cases, only a small flame seed remained in the recirculation zone. Together with the collision of the slit jets in the interaction jet region, the velocity gradients in the shear layers at the boundaries of the annular jets generate the turbulence. Turbulent mean and rms velocities were influenced by the presence of the flame, particularly in the recirculation zone. Flames with a high equivalence ratio were found to be more resistant to local extinction and exhibited a more corrugated and folded nature, particularly at high Reynolds numbers. For flames with a low equivalence ratio, local quenching and re-ignition processes maintained flames in the merged jet region, revealing a strong intermittency, which was substantiated by the increased principal strain rates for these flames. © 2015 Taylor & Francis Group, LLC.

  10. Droplet size measurement of diesel fuel spray particles using a planar laser-induced fluorescence method; Nijigen laser yuki keikoho wo mochiita diesel funmu ryushi no ryukei keisoku ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, N. [Isuzu Motors Ltd., Tokyo (Japan); Niimura, K. [Nissan Diesel Motor Co. Ltd., Saitama (Japan); Tsujimura, K.

    1997-11-25

    In this study, the planar laser-induced fluorescence (PLIF) technique was used to measure the mean size and size distribution of diesel spray particles. The fuel used was n-tridecane mixed with 1 wt% N, N, Nprime, Nprime-tetramethylparaphenyenediamine (TMPD). The light source used to excite the TMPD in the fuel was a secondary harmonic of a ruby laser-light sheet. A highly magnified image of the fluorescence from TMPD was taken by a 35 mm still camera with magnified optics, and the mean particle size and particle size distribution of the fuel spray were determined by processing the images of fuel particles printed on paper. First, the accuracy of this method was confirmed by comparison with results of Phase Doppler Anemometry for fuel spray of an air-assisted gasoline injector. Then, for the diesel spray, the effects of injection velocity, ambient pressure, geometric configuration of nozzle hole (i.e., nozzle hole diameter and nozzle hole L/D) and of measurement points on the fuel particle mean size and size distribution in a high-pressure vessel at atmospheric temperature were investigated. The results showed that the small size particles increase in number with increasing injection velocity. At higher injection velocity, seem to atomize more actively. With increasing ambient pressure, the mean particle size increases. A reduction in nozzle diameter resulted in no improvement of atomization in this study. Also, the mean particle size in the downstream region of the spray is larger than that in the upstream region of the spray. 16 refs., 19 figs., 3 tabs.

  11. Study and development of the laser induced breakdown spectroscopy (LIBS) for the realization of field measurements: application to analysis on-line of metals in liquids

    International Nuclear Information System (INIS)

    Rosado, J.C.D.

    2013-01-01

    Metal contamination of water is a major public health issue. Controls and treatments are more drastic and performed on them for human consumption. It is essential for this to possess reliable and sensitive analytical tools adapted to the existing regulations and flexible enough to use. The technique of 'Laser Induced Breakdown Spectroscopy' (LIBS), proven for the analysis of solids, including exo-terrestrial explorations, this very interesting advantages for liquids including, for example, are multi-character elementary and the possibility of in-situ measurements of water contamination by metals. A first part of this study thesis allowed to explore the potential (LIBS) for the analysis of dissolved metals or suspensions in water. Study has found an important effect related to the particle size in the analysis of suspensions. A second prong is to look at the effects of organic matrix represented by humic acid and those natural minerals represented by the bentonite and alumina particles. The matrix effect observed was corrected by normalization by internal standard. (author) [fr

  12. Novel estimation of the humification degree of soil organic matter by laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Edilene Cristina, E-mail: edilene@iq.unesp.br [Embrapa Instrumentation, Rua XV de Novembro, 1452, CEP 13560-970 São Carlos, SP (Brazil); São Paulo State University—UNESP, Analytical Chemistry Department, P.O. Box 355, 14801-970 Rua Prof. Francisco Degni, 55, CEP 14800-900 Araraquara, SP (Brazil); Ferreira, Ednaldo José, E-mail: ednaldo.ferreira@embrapa.br [Embrapa Instrumentation, Rua XV de Novembro, 1452, CEP 13560-970 São Carlos, SP (Brazil); Villas-Boas, Paulino Ribeiro, E-mail: paulino.villas-boas@embrapa.br [Embrapa Instrumentation, Rua XV de Novembro, 1452, CEP 13560-970 São Carlos, SP (Brazil); Senesi, Giorgio Saverio, E-mail: giorgio.senesi@ba.imip.cnr.it [Institute of Inorganic Methodologies and Plasmas, CNR, Bari 70126 (Italy); Carvalho, Camila Miranda, E-mail: camilamc@gmail.com [Embrapa Instrumentation, Rua XV de Novembro, 1452, CEP 13560-970 São Carlos, SP (Brazil); Physics Institute of São Carlos, University of São Paulo, IFSC-USP, Av. Trabalhador são-carlense, 400 Pq. Arnold Schimid, 13566-590 São Carlos, SP (Brazil); Romano, Renan Arnon, E-mail: renan.romano@gmail.com [Embrapa Instrumentation, Rua XV de Novembro, 1452, CEP 13560-970 São Carlos, SP (Brazil); Physics Institute of São Carlos, University of São Paulo, IFSC-USP, Av. Trabalhador são-carlense, 400 Pq. Arnold Schimid, 13566-590 São Carlos, SP (Brazil); Martin-Neto, Ladislau, E-mail: ladislau.martin@embrapa.br [Embrapa Instrumentation, Rua XV de Novembro, 1452, CEP 13560-970 São Carlos, SP (Brazil); and others

    2014-09-01

    Soil organic matter (SOM) constitutes an important reservoir of terrestrial carbon and can be considered an alternative for atmospheric carbon storage, contributing to global warming mitigation. Soil management can favor atmospheric carbon incorporation into SOM or its release from SOM to atmosphere. Thus, the evaluation of the humification degree (HD), which is an indication of the recalcitrance of SOM, can provide an estimation of the capacity of carbon sequestration by soils under various managements. The HD of SOM can be estimated by using various analytical techniques including fluorescence spectroscopy. In the present work, the potential of laser-induced breakdown spectroscopy (LIBS) to estimate the HD of SOM was evaluated for the first time. Intensities of emission lines of Al, Mg and Ca from LIBS spectra showing correlation with fluorescence emissions determined by laser-induced fluorescence spectroscopy (LIFS) reference technique were used to obtain a multivaried calibration model based on the k-nearest neighbor (k-NN) method. The values predicted by the proposed model (A-LIBS) showed strong correlation with LIFS results with a Pearson's coefficient of 0.87. The HD of SOM obtained after normalizing A-LIBS by total carbon in the sample showed a strong correlation to that determined by LIFS (0.94), thus suggesting the great potential of LIBS for this novel application. - Highlights: • Humification degree of soil organic matter (HD) • Importance of soil organic matter HD in keeping carbon in soil • Laser induced fluorescence spectroscopy (LIFS) for HD estimation (reference method) • New LIBS application to predict HD.

  13. Determination of strobilurin fungicide residues in fruits and vegetables by nonaqueous micellar electrokinetic capillary chromatography with indirect laser-induced fluorescence.

    Science.gov (United States)

    Guo, Xin; Wang, Kun; Chen, Guan-Hua; Shi, Jie; Wu, Xian; Di, Lu-Lu; Wang, Yi

    2017-08-01

    A nonaqueous micellar electrokinetic capillary chromatography method with indirect LIF was developed for the determination of strobilurin fungicide residues in fruits and vegetables. Hydrophobic CdTe quantum dots (QDs) synthesized in aqueous phase were used as background fluorescent substance. The BGE solution, QD concentration, and separation voltage were optimized to obtain the best separation efficiency and the highest signal intensity. The optimal BGE solution consists of 40 mM phosphate, 120 mM sodium dodecyl sulfate, 15% v/v water and 15% v/v hydrophobic CdTe QDs in formamide, of which apparent pH is 9.5. The optimized separation voltage is controlled as 25 kV. The resultant detection limits of azoxystrobin, kresoxim-methyl, and pyraclostrobin are all 0.001 mg/kg, their linear dynamic ranges are 0.005-2.5 mg/kg, and the recoveries of the spiked samples are 81.7-96.1%, 86.5-95.7%, and 87.3-97.4%, respectively. This method has been proved to be sensitive enough to detect the aforementioned fungicides in fruits and vegetables at the maximum residue limits. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Development of a 2D temperature measurement technique for combustion diagnostics using 2-line atomic fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Engstroem, Johan

    2001-01-01

    The present thesis is concerned with the development and application of a novel planar laser-induced fluorescence (PLIF) technique for temperature measurements in a variety of combusting flows. Accurate measurement of temperature is an essential task in combustion diagnostics, since temperature is one of the most fundamental quantities for the characterization of combustion processes. The technique is based on two-line atomic fluorescence (TLAF) from small quantities of atomic indium (In) seeded into the fuel. It has been developed from small-scale experiments in laboratory flames to the point where practical combustion systems can be studied. The technique is conceptually simple and reveals temperature information in the post-flame regions. The viability of the technique has been tested in three extreme measurement situations: in spark ignition engine combustion, in ultra-lean combustion situations such as lean burning aero-engine concepts and, finally, in fuel-rich combustion. TLAF was successfully applied in an optical Sl engine using isooctane as fuel. The wide temperature sensitivity, 700 - 3000 K, of the technique using indium atoms allowed measurements over the entire combustion cycle in the engine to be performed. In applications in lean combustion a potential problem caused by the strong oxidation processes of indium atoms was encountered. This limits measurement times due to deposits of absorbing indium oxide on measurement windows. The seeding requirement is a disadvantage of the technique and can be a limitation in some applications. The results from experiments performed in sooting flames are very promising for thermometry measurements in such environments. Absorption by hydrocarbons and other native species was found to be negligible. Since low laser energies and low seeding concentrations could be used, the technique did not, unlike most other incoherent optical thermometry techniques, suffer interferences from LII of soot particles or LIF from PAH

  15. Time resolved laser induced fluorescence on argon intermediate pressure microwave discharges: Measuring the depopulation rates of the 4p and 5p excited levels as induced by electron and atom collisions

    Science.gov (United States)

    Palomares, J. M.; Graef, W. A. A. D.; Hübner, S.; van der Mullen, J. J. A. M.

    2013-10-01

    The reaction kinetics in the excitation space of Ar is explored by means of Laser Induced Fluorescence (LIF) experiments using the combination of high rep-rate YAG-Dye laser systems with a well defined and easily controllable surfatron induced plasma setup. The high rep-rate favors the photon statistics while the low energy per pulse avoids intrusive plasma laser interactions. An analysis shows that, despite the low energy per pulse, saturation can still be achieved even when the geometrical overlap and spectral overlap are optimal. Out of the various studies that can be performed with this setup we confine the current paper to the study of the direct responses to the laser pump action of three 4p and one 5p levels of the Ar system. By changing the plasma in a controlled way one gets for these levels the rates of electron and atom quenching and therewith the total destruction rates of electron and atom collisions. Comparison with literature shows that the classical hard sphere collision rate derived for hydrogen gives a good description for the observed electron quenching (e-quenching) in Ar whereas for heavy particle quenching (a-quenching) this agreement was only found for the 5p level. An important parameter in the study of electron excitation kinetics is the location of the boundary in the atomic system for which the number of electron collisions per radiative life time equals unity. It is observed that for the Ar system this boundary is positioned lower than what is expected on grounds of H-like formulas.

  16. Novel estimation of the humification degree of soil organic matter by laser-induced breakdown spectroscopy

    Science.gov (United States)

    Ferreira, Edilene Cristina; Ferreira, Ednaldo José; Villas-Boas, Paulino Ribeiro; Senesi, Giorgio Saverio; Carvalho, Camila Miranda; Romano, Renan Arnon; Martin-Neto, Ladislau; Milori, Débora Marcondes Bastos Pereira

    2014-09-01

    Soil organic matter (SOM) constitutes an important reservoir of terrestrial carbon and can be considered an alternative for atmospheric carbon storage, contributing to global warming mitigation. Soil management can favor atmospheric carbon incorporation into SOM or its release from SOM to atmosphere. Thus, the evaluation of the humification degree (HD), which is an indication of the recalcitrance of SOM, can provide an estimation of the capacity of carbon sequestration by soils under various managements. The HD of SOM can be estimated by using various analytical techniques including fluorescence spectroscopy. In the present work, the potential of laser-induced breakdown spectroscopy (LIBS) to estimate the HD of SOM was evaluated for the first time. Intensities of emission lines of Al, Mg and Ca from LIBS spectra showing correlation with fluorescence emissions determined by laser-induced fluorescence spectroscopy (LIFS) reference technique were used to obtain a multivaried calibration model based on the k-nearest neighbor (k-NN) method. The values predicted by the proposed model (A-LIBS) showed strong correlation with LIFS results with a Pearson's coefficient of 0.87. The HD of SOM obtained after normalizing A-LIBS by total carbon in the sample showed a strong correlation to that determined by LIFS (0.94), thus suggesting the great potential of LIBS for this novel application.

  17. Influence of Laser Radiation Power Density on the Intensity of Spectral Lines for Main Components in a Clay Laser-Induced Plasma

    Science.gov (United States)

    Anufrik, S. S.; Kurian, N. N.; Znosko, K. F.; Belkov, M. V.

    2018-05-01

    We have studied the intensity of the spectral lines for the main components in clay: Al I 309.4 nm, Al II 358.7 nm, Mg II 279.6 nm, Ti II 323.6 nm vs. the position of the object relative to the focus of the optical system when the samples are exposed to single laser pulses from a YAG:Nd3+ laser. We have determined the permissible ranges for positioning the object relative to the focus of the optical system (positive and negative defocusing) for which there is practically no change in the reproducibility of the intensity for the spectral lines for red and white clay samples. We show that the position of the object relative to the focus of the optical system should be within the range ΔZ ±1.5 mm for optimal laser pulse energies for the analyte spectral lines. We have calculated the radiation flux density for different laser pulse energies and different distances from the focus to the object. We have shown experimentally that reducing the radiation flux density leads to a decrease in the intensity of the analyte spectral lines.

  18. Laser-induced nuclear fusion

    International Nuclear Information System (INIS)

    Jablon, Claude

    1977-01-01

    Research programs on laser-induced thermonuclear fusion in the United States, in Europe and in USSR are reviewed. The principle of the fusion reactions induced is explained, together with the theoretical effects of the following phenomena: power and type of laser beams, shape and size of the solid target, shock waves, and laser-hydrodynamics coupling problems [fr

  19. Quantitative planar laser-induced fluorescence imaging of multi-component fuel/air mixing in a firing gasoline-direct-injection engine: Effects of residual exhaust gas on quantitative PLIF

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Ben; Ewart, Paul [Department of Physics, Oxford University, Parks Road, Oxford OX1 3PU (United Kingdom); Wang, Xiaowei; Stone, Richard [Department of Engineering Science, Oxford University, Parks Road, Oxford OX1 3PJ (United Kingdom); Ma, Hongrui; Walmsley, Harold; Cracknell, Roger [Shell Global Solutions (UK), Shell Research Centre Thornton, P. O. Box 1, Chester, CH1 3SH (United Kingdom); Stevens, Robert; Richardson, David; Fu, Huiyu; Wallace, Stan [Jaguar Cars, Engineering Centre, Abbey Road, Whitley, Coventry, CV3 4LF (United Kingdom)

    2010-10-15

    A study of in-cylinder fuel-air mixing distributions in a firing gasoline-direct-injection engine is reported using planar laser-induced fluorescence (PLIF) imaging. A multi-component fuel synthesised from three pairs of components chosen to simulate light, medium and heavy fractions was seeded with one of three tracers, each chosen to co-evaporate with and thus follow one of the fractions, in order to account for differential volatility of such components in typical gasoline fuels. In order to make quantitative measurements of fuel-air ratio from PLIF images, initial calibration was by recording PLIF images of homogeneous fuel-air mixtures under similar conditions of in-cylinder temperature and pressure using a re-circulation loop and a motored engine. This calibration method was found to be affected by two significant factors. Firstly, calibration was affected by variation of signal collection efficiency arising from build-up of absorbing deposits on the windows during firing cycles, which are not present under motored conditions. Secondly, the effects of residual exhaust gas present in the firing engine were not accounted for using a calibration loop with a motored engine. In order to account for these factors a novel method of PLIF calibration is presented whereby 'bookend' calibration measurements for each tracer separately are performed under firing conditions, utilising injection into a large upstream heated plenum to promote the formation of homogeneous in-cylinder mixtures. These calibration datasets contain sufficient information to not only characterise the quantum efficiency of each tracer during a typical engine cycle, but also monitor imaging efficiency, and, importantly, account for the impact of exhaust gas residuals (EGR). By use of this method EGR is identified as a significant factor in quantitative PLIF for fuel mixing diagnostics in firing engines. The effects of cyclic variation in fuel concentration on burn rate are analysed for

  20. Laser induced florescence: application to spectroscopy and new microscopy imaging methods

    International Nuclear Information System (INIS)

    Galaup, L. P.

    2012-01-01

    Laser induced fluorescence is one of the light using techniques which allows the highest sensitivity for atoms and molecules detection, up to the single atom or single molecule level. This field is much too large for an extensive review; therefor we have chosen to focus on two main points: 1- the observation of laser stimulated fluorescence in phthalocyanine and porphyrin like molecules in rare gas and nitrogen matrices at low temperatures. 2- the presentation of laser induced fluorescence techniques suitable for achieving ultra-high spatial resolution imaging, below the diffraction limit of conventional microscopy, thanks to highly fluorescent molecules to be used as biological markers. (Author)

  1. Laser-induced multiphoton transitions

    International Nuclear Information System (INIS)

    Stenholm, S.

    1978-06-01

    Laser induced multiphoton processes are reviewed. The effects of strong fields on atoms are discussed. The perturbation treatment is presented and also its generalization to treat intermediate resonances. The influence of atomic coherence is discussed heuristically and the relation between quantal and classical descriptions of the field is elucidated by reference to the dressed atom description. Atomic ionization experiments are reviewed and the present understanding of multiphoton dissociation of molecules is explained. Finally some prospects for the future are discussed. (author)

  2. Efficient laser-induced 6-8 keV x-ray production from iron oxide aerogel and foil-lined cavity targets

    Energy Technology Data Exchange (ETDEWEB)

    Pérez, F.; Kay, J. J.; Patterson, J. R.; Kane, J.; Villette, B.; Girard, F.; Reverdin, C.; May, M.; Emig, J.; Sorce, C.; Colvin, J.; Gammon, S.; Jaquez, J.; Satcher, J. H.; Fournier, K. B.

    2012-08-01

    The performance of new iron-based laser-driven x-ray sources has been tested at the OMEGA laser facility for production of x rays in the 6.5–8.5 keV range. Two types of targets were experimentally investigated: low-density iron oxide aerogels (density 6-16 mg/cm36-16 mg/cm3) and stainless steel foil-lined cavity targets (steel thickness 1-5 μm1-5 μm). The targets were irradiated by 40 beams of the OMEGA laser (500 J/beam, 1 ns pulse, wavelength 351 nm). All targets showed good coupling with the laser, with <5%<5% of the incident laser light backscattered by the resulting plasma in all cases (typically <2.5%<2.5%). The aerogel targets produced Te=2Te=2 to 3 keV, ne=0.12-0.2ne=0.12-0.2 critical density plasmas yielding a 40%–60% laser-to-x-ray total conversion efficiency (CE) (1.2%–3% in the Fe K-shell range). The foil cavity targets produced Te~2 keV, Te~2 keV, ne~0.15ne~0.15 critical density plasmas yielding a 60%–75% conversion efficiency (1.6%–2.2% in the Fe K-shell range). Time-resolved images illustrate that the volumetric heating of low-density aerogels allow them to emit a higher K-shell x-ray yield even though they contain fewer Fe atoms. However, their challenging fabrication process leads to a larger shot-to-shot variation than cavity targets.

  3. Laser-Induced Breakdown Spectroscopy Infrared Emission From Inorganic and Organic Substances

    National Research Council Canada - National Science Library

    Yang, C.S; Brown, E; Hommerich, U; Trivedi, S. B; Snyder, A. P; Samuels, A. C

    2006-01-01

    Laser-induced breakdown spectroscopy (LIBS) has been established as a powerful method for identifying trace elemental contaminants by analyzing the atomic spectral emission lines that result subsequent to plasmas generated by laser power...

  4. On-line preconcentration of fluorescent derivatives of catecholamines in cerebrospinal fluid using flow-gated capillary electrophoresis.

    Science.gov (United States)

    Zhang, Qiyang; Gong, Maojun

    2016-06-10

    Flow-gated capillary electrophoresis (CE) coupled with microdialysis has become an important tool for in vivo bioanalytical measurements because it is capable of performing rapid and efficient separations of complex biological mixtures thus enabling high temporal resolution in chemical monitoring. However, the limit of detection (LOD) is often limited to a micro- or nano-molar range while many important target analytes have picomolar or sub-nanomolar levels in brain and other tissues. To enhance the capability of flow-gated CE for catecholamine detection, a novel and simple on-line sample preconcentration method was developed exclusively for fluorescent derivatives of catecholamines that were fluorogenically derivatized with naphthalene-2,3-dicarboxaldehyde (NDA) in the presence of cyanide. The effective preconcentration coupled with the sensitive laser-induced fluorescence (LIF) detection lowered the LOD down to 20pM for norepinephrine (NE) and 50pM for dopamine (DA) at 3-fold of S/N ratio, and the signal enhancement was estimated to be over 100-fold relative to normal injection when standard analytes were dissolved in artificial cerebrospinal fluid (aCSF). The basic focusing principle is novel since the sample plug contains borate while the background electrolyte (BGE) is void of borate. This strategy took advantage of the complexation between diols and borate, through which one negative charge was added to the complex entity. The sample derivatization mixture was electrokinetically injected into a capillary via the flow-gated injection, and then NE and DA derivatives were selectively focused to a narrow zone by the reversible complexation. Separation of NE and DA derivatives was executed by incoming surfactants of cholate and deoxycholate mixed in the front BGE plug. This on-line preconcentration method was finally applied to the detection of DA in rat cerebrospinal fluid (CSF) via microdialysis and on-line derivatization. It is anticipated that the method would

  5. Flow injection microfluidic device with on-line fluorescent derivatization for the determination of Cr(III) and Cr(VI) in water samples after solid phase extraction

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Guilong [Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Chongqing University, Chongqing, 400045 (China); Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University, Beijing, 100084 (China); He, Qiang, E-mail: heqiang0980@163.com [Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Chongqing University, Chongqing, 400045 (China); Lu, Ying [Department of Mathematics and Physics, Armed Police College, Chengdu, 610213 (China); Huang, Jing [Research Center for Advanced Computation, College of Science, Xihua University, Chengdu, 610039 (China); Lin, Jin-Ming, E-mail: jmlin@mail.tsinghua.edu.cn [Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University, Beijing, 100084 (China)

    2017-02-22

    In this paper, a rapid and simple method using magnetic multi-walled carbon nanotubes (MWCNTS), as a solid-phase extraction (SPE) sorbent, was successfully developed for extraction and preconcentration trace amounts of Cr(III) in water samples. The synthesized magnetic-MWCNTs nanocomposite was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). A rhodamine derivative (R1) was synthesized and characterized as a highly selective and sensitive fluorescent derivatizing agent for Cr(III). After SPE procedure, Cr(III) analysis was performed by flow injection microfluidic chip with on-line fluorescent derivatization and laser-induced fluorescence (LIF) spectroscopy detection. The parameters, which affected the efficiency of the developed method were investigated and optimized. Under the optimized conditions, the method exhibited a linear dynamic range of 0–10.0 nM, with a detection limit of 0.094 nM and an enrichment factor of 38. Furthermore, real water samples were analyzed and good recoveries were obtained from 91.0 to 101.6%. - Graphical abstract: Flow injection microfluidic device with on-line fluorescent derivatization and detection coupled to LIF. - Highlights: • A highly selective and sensitive derivatizing reagent for Cr(III) was synthesized and characterized. • The magnetic-MWCNTs nanocomposite as a SPE sorbent was successfully synthesized and characterized. • A new portable detection system was developed for microfluidic chip FIA platform.

  6. OI Fluorescent Line Contamination in Soft X-Ray Diffuse Background Obtained with Suzaku/XIS

    OpenAIRE

    Sekiya, Norio; Yamasaki, Noriko Y.; Mitsuda, Kazuhisa; Takei, Yoh

    2014-01-01

    The quantitative measurement of OVII line intensity is a powerful method for understanding the soft X-ray diffuse background. By systematically analyzing the OVII line intensity in 145 high-latitude Suzaku/XIS observations, the flux of OI fluorescent line in the XIS spectrum, contaminating the OVII line, is found to have an increasing trend with time especially after 2011. For these observations, the OVII line intensity would be overestimated unless taking into consideration the OI fluorescen...

  7. Combustion characteristics of stratified mixture. 1st Report. Measurement of mixture distribution in a constant-volume combustion chamber using laser-induced NO2 fluorescence; Sojo kongoki no nensho tokusei ni kansuru kenkyu. 1. Laser reiki NO2 keikoho ni yoru teiyo nenshokinai kongoki bunpu no keisoku

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, M.; Nishida, K.; Hiroyasu, H. [Hiroshima University, Hiroshima (Japan). Faculty of Engineering; Tabata, M. [Mazda Motor Corp., Hiroshima (Japan)

    1996-06-25

    Laser-induced fluorescence from nitrogen dioxide (NO2) as gas fuel tracer was applied to determine mixture stratification in a pancake-type constant-volume combustion chamber using propane and hydrogen fuels. The second-harmonic output of a pulsed Nd: YAG laser was used as a light source for fluorescence excitation. The fluorescence images were corrected by a gated image-intensified CCD camera. The quantitative analysis of fuel concentration was made possible by the application of linearity between fluorescence intensity and NO2 concentration at a low trace level. The stratified mixture (center-rich or center-lean) was concentrically formed in the central region of the chamber by a jet flow from a tangentially oriented port. The concentration difference in the radial direction of the chamber decreased with time from the start of injection. The rate of decrease was faster for hydrogen than for propane. After 300 ms from start of injection, however, the time histories of the concentration difference were nearly constant for both fuels regardless of overall concentration. 10 refs., 16 figs., 1 tab.

  8. Laser-induced damage in optical materials

    CERN Document Server

    Ristau, Detlev

    2014-01-01

    Dedicated to users and developers of high-powered systems, Laser-Induced Damage in Optical Materials focuses on the research field of laser-induced damage and explores the significant and steady growth of applications for high-power lasers in the academic, industrial, and military arenas. Written by renowned experts in the field, this book concentrates on the major topics of laser-induced damage in optical materials and most specifically addresses research in laser damage that occurs in the bulk and on the surface or the coating of optical components. It considers key issues in the field of hi

  9. [Selected enhancement of different order stokes lines of SRS by using fluorescence of mixed dye solution].

    Science.gov (United States)

    Zuo, Hao-yi; Gao, Jie; Yang, Jing-guo

    2007-03-01

    A new method to enhance the intensity of the different orders of Stokes lines of SRS by using mixed dye fluorescence is reported. The Stokes lines from the second-order to the fifth-order of CCl4 were enhanced by the fluorescence of mixed R6G and RB solutions in different proportions of 20:2, 20:13 and 20:40 (R6g:Rb), respectively. It is considered that the Stokes lines from the second-order to the fifth-order are near the fluorescence peaks of the three mixed solutions, and far from the absorption peaks of R6g and Rb, so the enhancement effect dominates the absorption effect; as a result, these stokes lines are enhanced. On the contrary, the first-order stokes line is near the absorption peak of RB and far from the fluorescence peaks of the mixed solutions, which leads to the weakening of this stokes line. It is also reported that the first-order, the second-order and the third-order Stokes lines of benzene were enhanced by the fluorescence of mixed solutions of R6g and DCM with of different proportions. The potential application of this method is forecasted.

  10. Correlation between grade of pearlite spheroidization and laser induced spectra

    Science.gov (United States)

    Yao, Shunchun; Dong, Meirong; Lu, Jidong; Li, Jun; Dong, Xuan

    2013-12-01

    Laser induced breakdown spectroscopy (LIBS) which is used traditionally as a spectrochemical analytical technique was employed to analyze the grade of pearlite spheroidization. Three 12Cr1MoV steel specimens with different grades of pearlite spheroidization were ablated to produce plasma by pulse laser at 266 nm. In order to determine the optimal temporal condition and plasma parameters for correlating the grade of pearlite spheroidization and laser induced spectra, a set of spectra at different delays were analyzed by the principal component analysis method. Then, the relationship between plasma temperature, intensity ratios of ionic to atomic lines and grade of pearlite spheroidization was studied. The analysis results show that the laser induced spectra of different grades of pearlite spheroidization can be readily identifiable by principal component analysis in the range of 271.941-289.672 nm with 1000 ns delay time. It is also found that a good agreement exists between the Fe ionic to atomic line ratios and the tensile strength, whereas there is no obvious difference in the plasma temperature. Therefore, LIBS may be applied not only as a spectrochemical analytical technique but also as a new way to estimate the grade of pearlite spheroidization.

  11. Correlation between grade of pearlite spheroidization and laser induced spectra

    International Nuclear Information System (INIS)

    Yao, Shunchun; Dong, Meirong; Lu, Jidong; Li, Jun; Dong, Xuan

    2013-01-01

    Laser induced breakdown spectroscopy (LIBS) which is used traditionally as a spectrochemical analytical technique was employed to analyze the grade of pearlite spheroidization. Three 12Cr1MoV steel specimens with different grades of pearlite spheroidization were ablated to produce plasma by pulse laser at 266 nm. In order to determine the optimal temporal condition and plasma parameters for correlating the grade of pearlite spheroidization and laser induced spectra, a set of spectra at different delays were analyzed by the principal component analysis method. Then, the relationship between plasma temperature, intensity ratios of ionic to atomic lines and grade of pearlite spheroidization was studied. The analysis results show that the laser induced spectra of different grades of pearlite spheroidization can be readily identifiable by principal component analysis in the range of 271.941–289.672 nm with 1000 ns delay time. It is also found that a good agreement exists between the Fe ionic to atomic line ratios and the tensile strength, whereas there is no obvious difference in the plasma temperature. Therefore, LIBS may be applied not only as a spectrochemical analytical technique but also as a new way to estimate the grade of pearlite spheroidization. (paper)

  12. Femtosecond laser-induced herringbone patterns

    Science.gov (United States)

    Garcell, Erik M.; Lam, Billy; Guo, Chunlei

    2018-06-01

    Femtosecond laser-induced herringbone patterns are formed on copper (Cu). These novel periodic structures are created following s-polarized, large incident angle, femtosecond laser pulses. Forming as slanted and axially symmetric laser-induced periodic surface structures along the side walls of ablated channels, the result is a series of v-shaped structures that resemble a herringbone pattern. Fluence mapping, incident angle studies, as well as polarization studies have been conducted and provide a clear understanding of this new structure.

  13. Laser induced breakdown spectroscopy in water | Boudjemai ...

    African Journals Online (AJOL)

    Sparks were generated in water by the focused beam of a Q-switched Nd:YAG laser Na and Cu aqueous solutions exhibited fluorescence signal on the decaying edge of plasma emission at their respective characteristic resonance lines. Potential of the laser plasma spectroscopy for in-situ pollution monitoring in natural ...

  14. Cine: Line excitation by infrared fluorescence in cometary atmospheres

    Science.gov (United States)

    de Val-Borro, Miguel; Cordiner, Martin A.; Milam, Stefanie N.; Charnley, Steven B.

    2017-03-01

    CINE is a Python module for calculating infrared pumping efficiencies that can be applied to the most common molecules found in cometary comae such as water, hydrogen cyanide or methanol. Excitation by solar radiation of vibrational bands followed by radiative decay to the ground vibrational state is one of the main mechanisms for molecular excitation in comets. This code calculates the effective pumping rates for rotational levels in the ground vibrational state scaled by the heliocentric distance of the comet. Line transitions are queried from the latest version of the HITRAN spectroscopic repository using the astroquery affiliated package of astropy. Molecular data are obtained from the LAMDA database. These coefficients are useful for modeling rotational emission lines observed in cometary spectra at sub-millimeter wavelengths. Combined with computational methods to solve the radiative transfer equations based, e.g., on the Monte Carlo algorithm, this model can retrieve production rates and rotational temperatures from the observed emission spectrum.

  15. 'Fluorescent Cell Chip' for immunotoxicity testing: Development of the c-fos expression reporter cell lines

    International Nuclear Information System (INIS)

    Trzaska, Dominika; Zembek, Patrycja; Olszewski, Maciej; Adamczewska, Violetta; Ulleras, Erik; Dastych, JarosIaw

    2005-01-01

    The Fluorescent Cell Chip for in vitro immunotoxicity testing employs cell lines derived from lymphocytes, mast cells, and monocytes-macrophages transfected with various EGFP cytokine reporter gene constructs. While cytokine expression is a valid endpoint for in vitro immunotoxicity screening, additional marker for the immediate-early response gene expression level could be of interest for further development and refinement of the Fluorescent Cell Chip. We have used BW.5147.3 murine thymoma transfected with c-fos reporter constructs to obtain reporter cell lines expressing ECFP under the control of murine c-fos promoter. These cells upon serum withdrawal and readdition and incubation with heavy metal compounds showed paralleled induction of c-Fos expression as evidenced by Real-Time PCR and ECFP fluorescence as evidenced by computer-supported fluorescence microscopy. In conclusion, we developed fluorescent reporter cell lines that could be employed in a simple and time-efficient screening assay for possible action of chemicals on c-Fos expression in lymphocytes. The evaluation of usefulness of these cells for the Fluorescent Cell Chip-based detection of immunotoxicity will require additional testing with a larger number of chemicals

  16. Laser induced breakdown spectroscopy library for the Martian environment

    International Nuclear Information System (INIS)

    Cousin, A.; Forni, O.; Maurice, S.; Gasnault, O.

    2011-01-01

    The NASA Mars Science Laboratory rover will carry the first Laser Induced Breakdown Spectroscopy experiment in space: ChemCam. We have developed a laboratory model which mimics ChemCam's main characteristics. We used a set of target samples relevant to Mars geochemistry, and we recorded individual spectra. We propose a data reduction scheme for Laser Induced Breakdown Spectroscopy data incorporating de-noising, continuum removal, and peak fitting. Known effects of the Martian atmosphere are confirmed with our experiment: better Signal-to-Noise Ratio on Mars compared to Earth, narrower peak width, and essentially no self-absorption. The wavelength shift of emission lines from air to Mars pressure is discussed. The National Institute of Standards and Technology vacuum database is used for wavelength calibration and to identify the elemental lines. Our Martian database contains 1336 lines for 32 elements: H, Li, Be, B, C, N, O, F, Na, Mg, Al, Si, P, S, Cl, K, Ar, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Rb, Sr, Cs, Ba, and Pb. It is a subset of the National Institute of Standards and Technology database to be used for Martian geochemistry. Finally, synthetic spectra can be built from the Martian database. Correlation calculations help to distinguish between elements in case of uncertainty. This work is used to create tools and support data for the interpretation of ChemCam results. - Highlights: ► Chemcam: first Laser Induced Breakdown Spectroscopy technique on Mars. ► Creation of a LIBS specific database to ChemCam on Mars. ► Data reduction scheme is proposed. ► Best signal under Martian conditions. ► LIBS emission lines database: subset of NIST database for Martian geochemistry.

  17. Double pulse laser ablation and plasma: Laser induced breakdown spectroscopy signal enhancement

    International Nuclear Information System (INIS)

    Babushok, V.I.; DeLucia, F.C.; Gottfried, J.L.; Munson, C.A.; Miziolek, A.W.

    2006-01-01

    A review of recent results of the studies of double laser pulse plasma and ablation for laser induced breakdown spectroscopy applications is presented. The double pulse laser induced breakdown spectroscopy configuration was suggested with the aim of overcoming the sensitivity shortcomings of the conventional single pulse laser induced breakdown spectroscopy technique. Several configurations have been suggested for the realization of the double pulse laser induced breakdown spectroscopy technique: collinear, orthogonal pre-spark, orthogonal pre-heating and dual pulse crossed beam modes. In addition, combinations of laser pulses with different wavelengths, different energies and durations were studied, thus providing flexibility in the choice of wavelength, pulse width, energy and pulse sequence. The double pulse laser induced breakdown spectroscopy approach provides a significant enhancement in the intensity of laser induced breakdown spectroscopy emission lines up to two orders of magnitude greater than a conventional single pulse laser induced breakdown spectroscopy. The double pulse technique leads to a better coupling of the laser beam with the plasma plume and target material, thus providing a more temporally effective energy delivery to the plasma and target. The experimental results demonstrate that the maximum effect is obtained at some optimum separation delay time between pulses. The optimum value of the interpulse delay depends on several factors, such as the target material, the energy level of excited states responsible for the emission, and the type of enhancement process considered. Depending on the specified parameter, the enhancement effects were observed on different time scales ranging from the picosecond time level (e.g., ion yield, ablation mass) up to the hundred microsecond level (e.g., increased emission intensity for laser induced breakdown spectroscopy of submerged metal target in water). Several suggestions have been proposed to explain

  18. N III Bowen Lines and Fluorescence Mechanism in the Symbiotic Star AG Peg

    Science.gov (United States)

    Hyung, Siek; Lee, Seong-Jae; Lee, Kang Hwan

    2018-03-01

    We have investigated the intensities and full width at half maximum (FWHM) of the high dispersion spectroscopic N III emission lines of AG Peg, observed with the Hamilton Echelle Spectrograph (HES) in three different epochs at Mt. Hamilton's Lick Observatory. The earlier theoretical Bowen line study assumed the continuum fluorescence effect, presenting a large discrepancy with the present data. Hence, we analyzed the observed N III lines assuming line fluorescence as the only suitable source: (1) The O III and N III resonance line profiles near λ 374 were decomposed, using the Gaussian function, and the contributions from various O III line components were determined. (2) Based on the theoretical resonant N III intensities, the expected N III Bowen intensities were obtained to fit the observed values. Our study shows that the incoming line photon number ratio must be considered to balance at each N III Bowen line level in the ultraviolet radiation according to the observed lines in the optical zone. We also found that the average FWHM of the N III Bowen lines was about 5 km·s-1 greater than that of the O III Bowen lines, perhaps due to the inherently different kinematic characteristics of their emission zones.

  19. Contributions to process monitoring by laser-induced breakdown spectroscopy

    Science.gov (United States)

    Rusak, David Alexander

    1998-12-01

    When a pulsed laser of sufficient energy and pulse duration is brought to a focus, multi-photon ionization creates free electrons in the focal volume. These electrons are accelerated in a process known as inverse Bremsstrahlung and cause collisional ionization of species in the focal volume. More charge carriers are produced and the process continues for the duration of the laser pulse. The manifestation of this process is a visible spark or plasma which typically lasts for tens of microseconds. This laser-induced plasma can serve as a source in an atomic emission experiment. Because the composition of the plasma is determined in large part by the environment in which it forms, elements in the laser target can be determined spectroscopically. The goal of a laser-induced breakdown spectroscopy (LIBS) experiment is to establish a relationship between the concentration of an element of interest in the target and the intensity of light emitted from the laser-induced plasma at a wavelength characteristic of that element. Because LIBS requires only optical access to the sample and can perform elemental determinations in solids, liquids, or gases with little sample preparation, there is interest in using it as an on-line technique for process monitoring in a number of industrial applications. However, before the technique becomes useful in industrial applications, many issues regarding instrumentation and data analysis need to be addressed in the lab. The first two chapters of this dissertation provide, respectively, the basics of the atomic emission experiment and a background of laser-induced breakdown spectroscopy. The next two chapters examine the effect of target water content on the laser-induced plasma and the use of LIBS for analysis of aqueous samples. Chapter 5 describes construction of a fiber optic LIBS probe and its use to study temporal electron number density evolution in plasmas formed on different metals. Chapter 6 is a study of excitation, vibrational

  20. Elemental analysis of halogens using molecular emission by laser-induced breakdown spectroscopy in air

    Energy Technology Data Exchange (ETDEWEB)

    Gaft, M.; Nagli, L.; Eliezer, N.; Groisman, Y. [Laser Distance Spectrometry, 9 Mota Gur St., Petah Tikva 49514 (Israel); Forni, O. [Université de Toulouse, UPS-OMP, IRAP, Toulouse (France); CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, F-31028 Toulouse cedex 4 (France)

    2014-08-01

    Fluorine and chlorine do not produce atomic and ionic line spectra of sufficient intensity to permit their detection by laser-induced breakdown spectroscopy. They do, however, combine with alkali-earths and other elements to form molecules whose spectra may be easily identified, enabling detection in ambient conditions with much higher sensitivity than using F I and Cl I atomic lines. - Highlights: • We studied laser induced breakdown spectra of halogens with alkali-earth elements. • Emission and temporal behavior of CaF and CaCl molecules were determined. • Sensitivity of F and Cl detection by molecules and atoms was compared.

  1. [Study on physical deviation factors on laser induced breakdown spectroscopy measurement].

    Science.gov (United States)

    Wan, Xiong; Wang, Peng; Wang, Qi; Zhang, Qing; Zhang, Zhi-Min; Zhang, Hua-Ming

    2013-10-01

    In order to eliminate the deviation between the measured LIBS spectral line and the standard LIBS spectral line, and improve the accuracy of elements measurement, a research of physical deviation factors in laser induced breakdown spectroscopy technology was proposed. Under the same experimental conditions, the relationship of ablated hole effect and spectral wavelength was tested, the Stark broadening data of Mg plasma laser induced breakdown spectroscopy with sampling time-delay from 1.00 to 3.00 micros was also studied, thus the physical deviation influences such as ablated hole effect and Stark broadening could be obtained while collecting the spectrum. The results and the method of the research and analysis can also be applied to other laser induced breakdown spectroscopy experiment system, which is of great significance to improve the accuracy of LIBS elements measuring and is also important to the research on the optimum sampling time-delay of LIBS.

  2. On-Line Monitoring of Fermentation Processes by Near Infrared and Fluorescence Spectroscopy

    DEFF Research Database (Denmark)

    Svendsen, Carina

    Monitoring and control of fermentation processes is important to ensure high product yield, product quality and product consistency. More knowledge on on-line analytical techniques such as near infrared and fluorescence spectroscopy is desired in the fermentation industry to increase the efficiency...... of on-line monitoring systems. The primary aim of this thesis is to elucidate and explore the dynamics in fermentation processes by spectroscopy. Though a number of successful on-line lab-scale monitoring systems have been reported, it seems that several challenges are still met, which limits the number...... of full-scale systems implemented in industrial fermentation processes. This thesis seeks to achieve a better understanding of the techniques near infrared and fluorescence spectroscopy and thereby to solve some of the challenges that are encountered. The thesis shows the advantages of applying real...

  3. A study of the reaction Li+HCl by the technique of time-resolved laser-induced fluorescence spectroscopy of Li (2 2PJ-2 2S1/2, λ=670.7 nm) between 700 and 1000 K

    Science.gov (United States)

    Plane, John M. C.; Saltzman, Eric S.

    1987-10-01

    A kinetic study is presented of the reaction between lithium atoms and hydrogen chloride over the temperature range 700-1000 K. Li atoms are produced in an excess of HCl and He bath gas by pulsed photolysis of LiCl vapor. The concentration of the metal atoms is then monitored in real time by the technique of laser-induced fluorescence of Li atoms at λ=670.7 nm using a pulsed nitrogen-pumped dye laser and box-car integration of the fluorescence signal. Absolute second-order rate constants for this reaction have been measured at T=700, 750, 800, and 900 K. At T=1000 K the reverse reaction is sufficiently fast that equilibrium is rapidly established on the time scale of the experiment. A fit of the data between 700 and 900 K to the Arrhenius form, with 2σ errors calculated from the absolute errors in the rate constants, yields k(T)=(3.8±1.1)×10-10 exp[-(883±218)/T] cm3 molecule-1 s-1. This result is interpreted through a modified form of collision theory which is constrained to take account of the conservation of total angular momentum during the reaction. Thereby we obtain an estimate for the reaction energy threshold, E0=8.2±1.4 kJ mol-1 (where the error arises from uncertainty in the exothermicity of the reaction), in very good agreement with a crossed molecular beam study of the title reaction, and substantially lower than estimates of E0 from both semiempirical and ab initio calculations of the potential energy surface.

  4. Laser induced forward transfer of graphene

    NARCIS (Netherlands)

    Smits, E.C.P.; Walter, A.; Leeuw, D.M. de; Asadi, K.

    2017-01-01

    Transfer of graphene and other two-dimensional materials is still a technical challenge. The 2D-materials are typically patterned after transfer, which leads to a major loss of material. Here, we present laser induced forward transfer of chemical vapor deposition grown graphene layers with

  5. On-line analysis of algae in water by discrete three-dimensional fluorescence spectroscopy.

    Science.gov (United States)

    Zhao, Nanjing; Zhang, Xiaoling; Yin, Gaofang; Yang, Ruifang; Hu, Li; Chen, Shuang; Liu, Jianguo; Liu, Wenqing

    2018-03-19

    In view of the problem of the on-line measurement of algae classification, a method of algae classification and concentration determination based on the discrete three-dimensional fluorescence spectra was studied in this work. The discrete three-dimensional fluorescence spectra of twelve common species of algae belonging to five categories were analyzed, the discrete three-dimensional standard spectra of five categories were built, and the recognition, classification and concentration prediction of algae categories were realized by the discrete three-dimensional fluorescence spectra coupled with non-negative weighted least squares linear regression analysis. The results show that similarities between discrete three-dimensional standard spectra of different categories were reduced and the accuracies of recognition, classification and concentration prediction of the algae categories were significantly improved. By comparing with that of the chlorophyll a fluorescence excitation spectra method, the recognition accuracy rate in pure samples by discrete three-dimensional fluorescence spectra is improved 1.38%, and the recovery rate and classification accuracy in pure diatom samples 34.1% and 46.8%, respectively; the recognition accuracy rate of mixed samples by discrete-three dimensional fluorescence spectra is enhanced by 26.1%, the recovery rate of mixed samples with Chlorophyta 37.8%, and the classification accuracy of mixed samples with diatoms 54.6%.

  6. Sorbitol as an efficient reducing agent for laser-induced copper deposition

    Science.gov (United States)

    Kochemirovsky, V. A.; Logunov, L. S.; Safonov, S. V.; Tumkin, I. I.; Tver'yanovich, Yu. S.; Menchikov, L. G.

    2012-10-01

    We have pioneered in revealing the fact that sorbitol may be used as an efficient reducing agent in the process of laser-induced copper deposition from solutions; in this case, it is possible to obtain copper lines much higher quality than by using conventional formalin.

  7. Filament-induced remote surface ablation for long range laser-induced breakdown spectroscopy operation

    International Nuclear Information System (INIS)

    Rohwetter, Ph.; Stelmaszczyk, K.; Woeste, L.; Ackermann, R.; Mejean, G.; Salmon, E.; Kasparian, J.; Yu, J.; Wolf, J.-P.

    2005-01-01

    We demonstrate laser induced ablation and plasma line emission from a metallic target at distances up to 180 m from the laser, using filaments (self-guided propagation structures ∼ 100 μm in diameter and ∼ 5 x 10 13 W/cm 2 in intensity) appearing as femtosecond and terawatt laser pulses propagating in air. The remarkable property of filaments to propagate over a long distance independently of the diffraction limit opens the frontier to long range operation of the laser-induced breakdown spectroscopy technique. We call this special configuration of remote laser-induced breakdown spectroscopy 'remote filament-induced breakdown spectroscopy'. Our results show main features of filament-induced ablation on the surface of a metallic sample and associated plasma emission. Our experimental data allow us to estimate requirements for the detection system needed for kilometer-range remote filament-induced breakdown spectroscopy experiment

  8. Optimization of cAMP fluorescence dataset from ACTOne cannabinoid receptor 1 cell line

    Directory of Open Access Journals (Sweden)

    Chaela S. Presley

    2016-06-01

    Full Text Available The ACTOne cannabinoid receptor 1 functional system is comprised of transfected HEK cells with the parental cyclic nucleotide gated channel (CNG co-transfected with cannabinoid receptor 1 (CB1. The ACTOne CB1 cell line was evaluated for cAMP driven fluorescence by optimizing experimental conditions for sensitivity to forskolin and CP 55,940, reading time point, reliability of cell passage number, and pertussis inactivation of Gi/o.

  9. Simultaneous separation of five major ribonucleic acids by capillary electrophoresis with laser-induced fluorescence in the presence of electroosmotic flow: application to the rapid screening of 5S rRNA from ovarian cancer cells.

    Science.gov (United States)

    Shih, Ya-Chu; Liao, Ching-Ru; Chung, I-Che; Chang, Yu-Sun; Chang, Po-Ling

    2014-10-17

    RNA integrity is important in RNA studies because poor RNA quality may impact downstream methodologies. This study proposes a rapid and cost-effective method for the determination of RNA integrity based on CE-LIF in the presence of electroosmotic flow. The proposed method uses poly(ethylene) oxide (Mavg=4,000,000 Da) as a sieving matrix for total RNA separation. Ethidium bromide (μg mL(-1)) was dissolved in a polymer solution as an interchelating dye for on-column fluorescent labeling. The 28S rRNA, 18S rRNA, 5.8S rRNA, 5S rRNA and tRNA from the total human RNA extracted from the cells were fully separated using the proposed method. The lowest detectable concentration of total RNA achieved was 100 pg μL(-1) with a 6 min sample injection followed by on-column concentration. In addition, the temperature-induced degradation of total RNA was observed by CE-LIF. The electropherograms revealed more fragmentation of 28S and 18S rRNAs by temperature-induced hydrolysis compared with the 5.8S rRNA, 5S rRNA and tRNA. Therefore, the results indicated that RNA degradation should be considered for long-term, high-temperature incubations in RNA-related experiments involving RNA hybridization. The proposed method is furthermore, applied to the determination of 5S rRNA overexpressed in ovarian cancer cells as compared to the cervical cancer cells. Overall, CE-LIF is highly promising for rapid screening of ovarian cancers without tedious pre-amplification steps. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Laser-induced plasma spectrometry: truly a surface analytical tool

    International Nuclear Information System (INIS)

    Vadillo, Jose M.; Laserna, J.

    2004-01-01

    For a long period, analytical applications of laser induced plasma spectrometry (LIPS) have been mainly restricted to overall and quantitative determination of elemental composition in bulk, solid samples. However, introduction of new compact and reliable solid state lasers and technological development in multidimensional intensified detectors have made possible the seeking of new analytical niches for LIPS where its analytical advantages (direct sampling from any material irrespective of its conductive status without sample preparation and with sensitivity adequate for many elements in different matrices) could be fully exploited. In this sense, the field of surface analysis could take advantage from the cited advantages taking into account in addition, the capability of LIPS for spot analysis, line scan, depth-profiling, area analysis and compositional mapping with a single instrument in air at atmospheric pressure. This review paper outlines the fundamental principles of laser-induced plasma emission relevant to sample surface studies, discusses the experimental parameters governing the spatial (lateral and in-depth) resolution in LIPS analysis and presents the applications concerning surface examination

  11. Identification of quantum dots labeled metallothionein by fast scanning laser-induced breakdown spectroscopy

    International Nuclear Information System (INIS)

    Konecna, Marie; Novotny, Karel; Krizkova, Sona; Blazkova, Iva; Kopel, Pavel; Kaiser, Jozef; Hodek, Petr; Kizek, Rene

    2014-01-01

    The technique described in this paper allows detection of quantum dots (QDs) specifically deposited on the polystyrene surface by laser-induced breakdown spectroscopy (LIBS). Using LIBS, the distribution of QDs or their conjugates with biomolecules deposited on the surface can be observed, regardless of the fact if they exhibit fluorescence or not. QDs deposited on the specific surface of polystyrene microplate in the form of spots are detected by determination of the metal included in the QDs structure. Cd-containing QDs (CdS, CdTe) stabilized with mercaptopropionic (MPA) or mercaptosuccinic (MSA) acid, respectively, alone or in the form of conjugates with metallothionein (MT) biomolecule are determined by using the 508.58 nm Cd emission line. The observed absolute detection limit for Cd in CdTe QDs conjugates with MT in one spot was 3 ng Cd. Due to the high sensitivity of this technique, the immunoanalysis in combination with LIBS was also investigated. Cd spatial distribution in sandwich immunoassay was detected. - Highlights: • We describe determination of biomolecules labeled with quantum dots by LIBS. • LIBS and immunoassay are applied for the determination of metallothionein. • Metallothionein amount detected by LIBS is 10-times lower compared to ELISA

  12. Identification of quantum dots labeled metallothionein by fast scanning laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Konecna, Marie [Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, CZ-616 00 Brno (Czech Republic); Department of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno (Czech Republic); Novotny, Karel [Central European Institute of Technology, Masaryk University, Kamenice 753/5, CZ-625 00 Brno (Czech Republic); Krizkova, Sona [Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, CZ-616 00 Brno (Czech Republic); Department of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno (Czech Republic); Blazkova, Iva [Department of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno (Czech Republic); Kopel, Pavel [Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, CZ-616 00 Brno (Czech Republic); Department of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno (Czech Republic); Kaiser, Jozef [Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, CZ-616 00 Brno (Czech Republic); Institute of Physical Engineering, Brno University of Technology, Technicka 2, CZ-616 69 Brno (Czech Republic); Hodek, Petr [Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 2030/8, CZ-128 00 Prague,Czech Republic (Czech Republic); Kizek, Rene [Central European Institute of Technology, Brno University of Technology, Technicka 3058/10, CZ-616 00 Brno (Czech Republic); Department of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno (Czech Republic); and others

    2014-11-01

    The technique described in this paper allows detection of quantum dots (QDs) specifically deposited on the polystyrene surface by laser-induced breakdown spectroscopy (LIBS). Using LIBS, the distribution of QDs or their conjugates with biomolecules deposited on the surface can be observed, regardless of the fact if they exhibit fluorescence or not. QDs deposited on the specific surface of polystyrene microplate in the form of spots are detected by determination of the metal included in the QDs structure. Cd-containing QDs (CdS, CdTe) stabilized with mercaptopropionic (MPA) or mercaptosuccinic (MSA) acid, respectively, alone or in the form of conjugates with metallothionein (MT) biomolecule are determined by using the 508.58 nm Cd emission line. The observed absolute detection limit for Cd in CdTe QDs conjugates with MT in one spot was 3 ng Cd. Due to the high sensitivity of this technique, the immunoanalysis in combination with LIBS was also investigated. Cd spatial distribution in sandwich immunoassay was detected. - Highlights: • We describe determination of biomolecules labeled with quantum dots by LIBS. • LIBS and immunoassay are applied for the determination of metallothionein. • Metallothionein amount detected by LIBS is 10-times lower compared to ELISA.

  13. Infrared laser-induced chemical reactions

    International Nuclear Information System (INIS)

    Katayama, Mikio

    1978-01-01

    The experimental means which clearly distinguishes between infrared ray-induced reactions and thermal reactions has been furnished for the first time when an intense monochromatic light source has been obtained by the development of infrared laser. Consequently, infrared laser-induced chemical reactions have started to develop as one field of chemical reaction researches. Researches of laser-induced chemical reactions have become new means for the researches of chemical reactions since they were highlighted as a new promising technique for isotope separation. Specifically, since the success has been reported in 235 U separation using laser in 1974, comparison of this method with conventional separation techniques from the economic point of view has been conducted, and it was estimated by some people that the laser isotope separation is cheaper. This report briefly describes on the excitation of oscillation and reaction rate, and introduces the chemical reactions induced by CW laser and TEA CO 2 laser. Dependence of reaction yield on laser power, measurement of the absorbed quantity of infrared ray and excitation mechanism are explained. Next, isomerizing reactions are reported, and finally, isotope separation is explained. It was found that infrared laser-induced chemical reactions have the selectivity for isotopes. Since it is evident that there are many examples different from thermal and photo-chemical reactions, future collection of the data is expected. (Wakatsuki, Y.)

  14. Analysis of fresco by laser induced breakdown spectroscopy

    International Nuclear Information System (INIS)

    Caneve, L.; Diamanti, A.; Grimaldi, F.; Palleschi, G.; Spizzichino, V.; Valentini, F.

    2010-01-01

    The laser-based techniques have been shown to be a very powerful tool for artworks characterization and are used in the field of cultural heritage for the offered advantages of minimum invasiveness, in situ applicability and high sensitivity. Laser induced breakdown spectroscopy, in particular, has been applied in this field to many different kinds of ancient materials with successful results. In this work, a fragment of a Roman wall painting from the archaeological area of Pompeii has been investigated by LIBS. The sample elemental composition resulting from LIBS measurements suggested the presence of certain pigments. The ratio of the intensities of different lines related to some characteristic elements is proposed as an indicator for pigment recognition. The depth profiling permitted to put in evidence the presence of successive paint layers with different compositions. A comparison with the results obtained by the microscopy inspection of the sample has been done.

  15. Time evolution of laser-induced breakdown spectrometry of lead

    International Nuclear Information System (INIS)

    Li Zhongwen; Zhang Jianhui

    2011-01-01

    The plasma have been generated by a pulsed Nd: YAG laser at the fundamental wavelength of 1.06 μm ablating a metal lead target in air at atmospheric pressure, and the time resolved emission spectra were gotten. Time evolution of electron temperatures were measured according to the wavelength and relative intensity of spectra; then the electron densities were obtained from the Stark broadening of Pb-line; the time evolution of electron temperatures and electron densities along the direction plumbing the target surface were imaged. The analysis of results showed that electron temperature averaged to 14500 K, electron densities up to 10 17 cm -3 . The characteristics of time evolution of electron temperature and electron density were qualitatively explained from the aspect of generation mechanism of laser-induced plasmas. (authors)

  16. Titanium monoxide spectroscopy following laser-induced optical breakdown

    International Nuclear Information System (INIS)

    Parigger, Christian G.; Woods, Alexander C.; Keszler, Anna; Nemes, László; Hornkohl, James O.

    2012-01-01

    This work investigates Titanium Monoxide (TiO) in ablation-plasma by employing laser-induced breakdown spectroscopy (LIBS) with 1 to 10 TW/cm 2 irradiance, pulsed, 13 nanosecond, Q-switched Nd:YAG laser radiation at the fundamental wavelength of 1064 nm. The analysis of TiO is based on our first accurate determination of transition line strengths for selected TiO A-X, B-X, and E-X transitions, particularly TiO A-X γ and B-X γ′ bands. Electric dipole line strengths for the A 3 Φ-X 3 δ and B 3 Π-X 3 δ bands of TiO are computed. The molecular TiO spectra are observed subsequent to laser-induced breakdown (LIB). We discuss analysis of diatomic molecular spectra that may occur simultaneously with spectra originating from atomic species. Gated detection is applied to investigate the development in time of the emission spectra following LIB. Collected emission spectra allow one to infer micro-plasma parameters such as temperature and electron density. Insight into the state of the micro-plasma is gained by comparing measurements with predictions of atomic and molecular spectra. Nonlinear fitting of recorded and computed diatomic spectra provides the basis for molecular diagnostics, while atomic species may overlap and are simultaneously identified. Molecular diagnostic approaches similar to TiO have been performed for diatomic molecules such as AlO, C 2 , CN, CH, N 2 , NH, NO and OH.

  17. Laser induced forward transfer of soft materials

    International Nuclear Information System (INIS)

    Palla-Papavlu, A; Dinca, V; Luculescu, C; Dinescu, M; Shaw-Stewart, J; Lippert, T; Nagel, M

    2010-01-01

    A strong research effort is presently aimed at patterning methodologies for obtaining controlled defined micrometric polymeric structures for a wide range of applications, including electronics, optoelectronics, sensors, medicine etc. Lasers have been identified as appropriate tools for processing of different materials, such as ceramics and metals, but also for soft, easily damageable materials (biological compounds and polymers). In this work we study the dynamics of laser induced forward transfer (LIFT) with a gap between the donor and the receiver substrates, which is the basis for possible applications that require multilayer depositions with high spatial resolution

  18. The description of compton lines in energy-dispersive x-ray Fluorescence

    International Nuclear Information System (INIS)

    Van Gysel, Mon; Van Espen, P.J.M.

    2001-01-01

    Energy-Dispersive X-Ray Fluorescence (ED-XRF) is a non-destructive technique for the element analysis in a concentration range ppm - % making use of X rays up to 100 keV. Generally, two photon matter interactions occur, respectively absorption and scattering. The absorption of incident photons gives raise to characteristic lines. Scattering gives an incoherent and a coherent line. A Gaussian peak model is adequate to describe the characteristic and coherent scattered lines. Incoherent lines appear as non-Gaussian, broadened peaks. The profile of a Compton peak is complex. It depends on the geometry and the composition of the sample. Especially, when analyzing a low Z matrix; dominant scattering and multiple scattering may cause large interferences. The absence of an appropriate fitting model makes the Compton profile seen as a limiting factor in the evaluation of spectra. An accurate description of incoherent lines should improve quantitative analysis. Therefore, a suitable fitting model, making use of the expertise of non-linear least squares procedures and Monte-Carlo calculations was systematically investigated. The proposed model, containing a modified Gaussian, is tested on experimental data recorded with a HPGe detector

  19. Harvard ER-2 OH laser-induced fluorescence instrument

    Science.gov (United States)

    Wennberg, Paul O.; Anderson, James G.

    1994-01-01

    The Harvard ER-2 OH instrument is scheduled to be integrated into the NASA ER-2 high altitude aircraft ozone payload in August 1992. Design and fabrication is presently underway. This experiment is a descendant of a balloon borne instrument designed and built in the mid-1980s. The ER-2 instrument is being designed to measure OH and HO2 as part of the NASA ozone payload for the investigation of processes controlling the concentration of stratospheric ozone. Although not specifically designed to do so, it is hoped that valid measurements of OH and HO2 can be made in the remote free troposphere with this instrument.

  20. Surface Thermometry of Energetic Materials by Laser-Induced Fluorescence

    Science.gov (United States)

    1989-09-01

    at 34 yttrium- aluminum -garnet (Dy:YAG). The simplified energy diagram of Dy:YAG is shown in Fig. 1. Absorbed laser light (at 355 nrm) can 5 excite the...the thermometric technique on a surface similar to that of an energetic material, a thermal-setting plastic supplied by Buehler, Ltd., was employed...temperature over the temperature range of interest. The rare-earth ion dysprosium (Dy) doped into a yttrium- aluminum -garnet (YAG) crystal was I determined

  1. Detection of vegetation LUE based on chlorophyll fluorescence separation algorithm from Fraunhofer line

    Science.gov (United States)

    Liu, Liangyun; Zhang, Bing

    2009-09-01

    Photosynthetic efficiency is very important, and not yet generally assessable by remote sensing. Much research has proved the possibility of the separation of solar-induced chlorophyll fluorescence (ChlF) from the reflected hyperspectral data. As the 'probe' of plant photosynthesis, it is possible to detect photosynthetic light use efficiency (LUE) by the separated solar-induced ChlF. A diurnal experiment was carried out on winter wheat on Apr. 18, 2008, and the canopy radiance spectra and leaf LUE data were measured synchronously. The solar-induced chlorophyll fluorescence signals at 760nm and 688nm were separated from the reflected radiance spectral based on Fraunhofer lines in two oxygen absorption bands. The result showed that LUE was negatively correlated to the separated chlorophyll signals. The statistical models for LUE based on the solar-induced chlorophyll fluorescence values at 688 nm and 760 nm bands had correlation coefficients (R2) of 0.64 and 0.78, respectively. In addition, photochemical reflectance index (PRI) was also linked to LUE, and a statistical model for LUE based on PRI has a correlation coefficient (R2) of 0.66. The presented method provides a novel solution for monitoring LUE from remote sensing data.

  2. [Establishment and identification of mouse lymphoma cell line EL4 expressing red fluorescent protein].

    Science.gov (United States)

    Li, Yan-Jie; Cao, Jiang; Chen, Chong; Wang, Dong-Yang; Zeng, Ling-Yu; Pan, Xiu-Ying; Xu, Kai-Lin

    2010-02-01

    This study was purposed to construct a lentiviral vector encoding red fluorescent protein (DsRed) and transfect DsRed into EL4 cells for establishing mouse leukemia/lymphoma model expressing DsRed. The bicistronic SIN lentiviral transfer plasmid containing the genes encoding neo and internal ribosomal entry site-red fluorescent protein (IRES-DsRed) was constructed. Human embryonic kidney 293FT cells were co-transfected with the three plasmids by liposome method. The viral particles were collected and used to transfect EL4 cells, then the cells were selected by G418. The results showed that the plasmid pXZ208-neo-IRES-DsRed was constructed successfully, and the viral titer reached to 10(6) U/ml. EL4 cells were transfected by the viral solution efficiently. The transfected EL4 cells expressing DsRed survived in the final concentration 600 microg/ml of G418. The expression of DsRed in the transfected EL4 cells was demonstrated by fluorescence microscopy and flow cytometry. In conclusion, the EL4/DsRed cell line was established successfully.

  3. On-line monitoring of fermentation processes using multi-wavelength fluorescence

    DEFF Research Database (Denmark)

    Odman, Peter; Petersen, Nanna; Johansen, Claus Lindvald

    2007-01-01

    . The model system considered in this work is the antibiotic production by Streptomyces coelicolor, a filamentous bacterium. In addition to predicting concentrations of biomass in the fermentation broth, the data allowed detection of different physiological states, i.e. growth phase and phosphate limitation......Fermentation processes often suffer from a lack of real-time methods for on-line determination of variables like the concentrations of nutrients and products. This work aims at investigating the possibilities of implementing an on-line fermentation monitoring system based on multi......-wavelength fluorescence (MWF). This type of sensor has previously showed promising accuracy and selectivity for in situ monitoring of cell mass and certain metabolites in bioreactors (Lantz et al., 2006). The sensor generates multivariate data outputs, which necessitate chemometric modeling for signal interpretation...

  4. Laser-induced ionization of Na vapor

    International Nuclear Information System (INIS)

    Wu, R.C.Y.; Judge, D.L.; Roussel, F.; Carre, B.; Breger, P.; Spiess, G.

    1982-01-01

    The production of Na 2 + ions by off-resonant laser excitation in the 5800-6200A region mainly results from two-photon absorption by the Na 2 molecule to highly excited gerade states followed by (a) direct ionization by absorbing a third photon or (b) coupling to the molecular Na 2 D 1 PIμ Rydberg state which is subsequently ionized by absorbing a third photon. This mechanism, i.e., a two-photon resonance three photon ionization process, explains a recent experimental observation of Roussel et al. It is suggested that the very same mechanism is also responsible for a similar observation reported by Polak-Dingels et al in their work using two crossed Na beams. In the latter two studies the laser-induced associative ionization processes were reported to be responsible for producing the Na 2 + ion. From the ratio of molecular to atomic concentration in the crossed beam experiment of Polak-Dingels et al we estimate that the cross section for producing Na 2 + through laser-induced associative ionization is at least four orders of magnitude smaller than ionization through the two-photon resonance three photon ionization process in Na 2 molecules

  5. [Study of enhancement effect of laser-induced crater on plasma radiation].

    Science.gov (United States)

    Chen, Jin-Zhong; Zhang, Xiao-Ping; Guo, Qing-Lin; Su, Hong-Xin; Li, Guang

    2009-02-01

    Single pulses exported from high-energy neodymium glass laser were used to act on the same position of soil sample surface repeatedly, and the plasma emission spectra generated from sequential laser pulse action were collected by spectral recording system. The experimental results show that the laser-induced soil plasma radiation was enhanced continuously under the confinement effect of the crater walls, and the line intensities and signal-to-background ratios both had different improvements along with increasing the number of acting pulses. The photographs of the plasma image and crater appearance were taken to study the plasma shape, laser-induced crater appearance, and the mass of the ablated sample. The internal mechanism behind that laser-induced crater enhanced plasma radiation was researched. Under the sequential laser pulse action, the forming plasma as a result enlarges gradually first, leading to distortion at the trail of plasma plume, and then, its volume diminishes slowly. And also, the color of the plasma changes from buff to white gradually, which implies that the temperature increases constantly. The laser-induced crater had a regular shape, that is, the diameter increased from its bottom to top gradually, thus forming a taper. The mass of the laser-ablated substance descends along with increasing the amount of action pulse. Atomization degree of vaporized substance was improved in virtue of the crater confinement effect, Fresnel absorption produced from the crater walls reflection, and the inverse bremsstrahlung, and the plasma radiation intensity was enhanced as a result.

  6. Laser-induced breakdown spectroscopy measurement of a small fraction of rhenium in bulk tungsten

    Science.gov (United States)

    Nishijima, D.; Ueda, Y.; Doerner, R. P.; Baldwin, M. J.; Ibano, K.

    2018-03-01

    Laser-induced breakdown spectroscopy (LIBS) of bulk rhenium (Re) and tungsten (W)-Re alloy has been performed using a Q-switched Nd:YAG laser (wavelength = 1064 nm, pulse width ∼4-6 ns, laser energy = 115 mJ). It is found that the electron temperature, Te, of laser-induced Re plasma is lower than that of W plasma, and that Te of W-Re plasma is in between Re and W plasmas. This indicates that material properties affect Te in a laser-induced plasma. For analysis of W-3.3%Re alloy, only the strongest visible Re I 488.9 nm line is found to be used because of the strong enough intensity without contamination with W lines. Using the calibration-free LIBS method, the atomic fraction of Re, cRe, is evaluated as a function of the ambient Ar gas pressure, PAr. At PAr 10 Torr due to spectral overlapping of the Re I 488.9 nm line by an Ar II 488.9 nm line.

  7. Spectrophotometry near the atmospheric cutoff of the strongest Bowen resonance fluorescence lines of O III in two planetary nebulae

    Science.gov (United States)

    O'Dell, C. R.; Opal, Chet B.

    1989-01-01

    Spectrophotometric results are presented for the stronger, well-resolved Bowen O III resonance fluorescence emission lines in the planetary nebulae 7027 and NGC 7662 down to and including the intrinsically strong line at 3133 A. These data are combined with results from the IUE atlas of spectra and similar results for the longer wavelength lines by Likkel and Aller (1986) to give the first full coverage of the Bowen lines. Good agreement is found with fluorescence theory for the primary cascade lines, except for the Likkel and Aller results. The efficiency of conversion of the exciting He II Ly-alpha into O III lines is determined, and values comparable to other planetary nebulae are found.

  8. Process analysis of recycled thermoplasts from consumer electronics by laser-induced plasma spectroscopy.

    Science.gov (United States)

    Fink, Herbert; Panne, Ulrich; Niessner, Reinhard

    2002-09-01

    An experimental setup for direct elemental analysis of recycled thermoplasts from consumer electronics by laser-induced plasma spectroscopy (LIPS, or laser-induced breakdown spectroscopy, LIBS) was realized. The combination of a echelle spectrograph, featuring a high resolution with a broad spectral coverage, with multivariate methods, such as PLS, PCR, and variable subset selection via a genetic algorithm, resulted in considerable improvements in selectivity and sensitivity for this complex matrix. With a normalization to carbon as internal standard, the limits of detection were in the ppm range. A preliminary pattern recognition study points to the possibility of polymer recognition via the line-rich echelle spectra. Several experiments at an extruder within a recycling plant demonstrated successfully the capability of LIPS for different kinds of routine on-line process analysis.

  9. Laser-Induced Damage with Femtosecond Pulses

    Science.gov (United States)

    Kafka, Kyle R. P.

    The strong electric fields of focused femtosecond laser pulses lead to non-equilibrium dynamics in materials, which, beyond a threshold intensity, causes laser-induced damage (LID). Such a strongly non-linear and non-perturbative process renders important LID observables like fluence and intensity thresholds and damage morphology (crater) extremely difficult to predict quantitatively. However, femtosecond LID carries a high degree of precision, which has been exploited in various micro/nano-machining and surface engineering applications, such as human eye surgery and super-hydrophobic surfaces. This dissertation presents an array of experimental studies which have measured the damage behavior of various materials under femtosecond irradiation. Precision experiments were performed to produce extreme spatio-temporal confinement of the femtosecond laser-solid damage interaction on monocrystalline Cu, which made possible the first successful direct-benchmarking of LID simulation with realistic damage craters. A technique was developed to produce laser-induced periodic surface structures (LIPSS) in a single pulse (typically a multi-pulse phenomenon), and was used to perform a pump-probe study which revealed asynchronous LIPSS formation on copper. Combined with 1-D calculations, this new experimental result suggests more drastic electron heating than expected. Few-cycle pulses were used to study the LID performance and morphology of commercial ultra-broadband optics, which had not been systematically studied before. With extensive surface analysis, various morphologies were observed, including LIPSS, swelling (blisters), simple craters, and even ring-shaped structures, which varied depending on the coating design, number of pulses, and air/vacuum test environment. Mechanisms leading to these morphologies are discussed, many of which are ultrafast in nature. The applied damage behavior of multi-layer dielectric mirrors was measured and compared between long pulse (150 ps

  10. Study of Bacterial Samples Using Laser Induced Breakdown Spectroscopy

    International Nuclear Information System (INIS)

    Farooq W A; Atif M; Tawfik W; Alsalhi M S; Alahmed Z A; Sarfraz M; Singh J P

    2014-01-01

    Laser-induced breakdown spectroscopy (LIBS) technique has been applied to investigate two different types of bacteria, Escherichia coli (B1) and Micrococcus luteus (B2) deposited on glass slides using Spectrolaser 7000. LIBS spectra were analyzed using spectrolaser software. LIBS spectrum of glass substrate was compared with bacteria spectra. Ca, Mg, Na, K, P, S, Cl, Fe, Al, Mn, Cu, C, H and CN-band appeared in bacterial samples in air. Two carbon lines at 193.02 nm, 247.88 nm and one hydrogen line at 656.28 nm with intensity ratios of 1.9, 1.83 and 1.53 appeared in bacterial samples B1 and B2 respectively. Carbon and hydrogen are the important components of the bio-samples like bacteria and other cancer cells. Investigation on LIBS spectra of the samples in He and Ar atmospheres is also presented. Ni lines appeared only in B2 sample in Ar atmosphere. From the present experimental results we are able to show that LIBS technique has a potential in the identification and discrimination of different types of bacteria. (plasma technology)

  11. Basic design of on-line analyzer for sheet paper using X-ray fluorescence (XRF) technique

    International Nuclear Information System (INIS)

    Rony Djokorayono; Ahmad Suntoro; Ikhsan Shobari; Usep Setia Gunawan

    2016-01-01

    Basic design of on-line analyzer for sheet paper using X-ray fluorescence technique has been carried out. Compared with sampling technique, this X-ray fluorescence technique has some advantages in term of analysis accuracy and time. The design activities performed including the establishment of design requirements, functional requirements, technical requirements, technical specification, detection sub-system design, data acquisition sub-system design, and operator computer console design. This program will use silicon drift or CdTe X-ray detector to detect X-ray fluorescence emitted by elements in sheet paper due to X-ray interaction of a X-ray source, 55 Fe (Ferro-55).This basic design of on-line analyzer for sheet paper using X-ray fluorescence technique should be followed up with the development of detailed design, prototype construction, and field testing. (author)

  12. Laser induced single spot oxidation of titanium

    Energy Technology Data Exchange (ETDEWEB)

    Jwad, Tahseen, E-mail: taj355@bham.ac.uk; Deng, Sunan; Butt, Haider; Dimov, S.

    2016-11-30

    Highlights: • A new high resolution laser induced oxidation (colouring) method is proposed (single spot oxidation). • The method is applied to control oxide films thicknesses and hence colours on titanium substrates in micro-scale. • The method enable imprinting high resolution coloured image on Ti substrate. • Optical and morphological periodic surface structures are also produced by an array of oxide spots using the proposed method. • Colour coding of two colours into one field is presented. - Abstract: Titanium oxides have a wide range of applications in industry, and they can be formed on pure titanium using different methods. Laser-induced oxidation is one of the most reliable methods due to its controllability and selectivity. Colour marking is one of the main applications of the oxidation process. However, the colourizing process based on laser scanning strategies is limited by the relative large processing area in comparison to the beam size. Single spot oxidation of titanium substrates is proposed in this research in order to increase the resolution of the processed area and also to address the requirements of potential new applications. The method is applied to produce oxide films with different thicknesses and hence colours on titanium substrates. High resolution colour image is imprinted on a sheet of pure titanium by converting its pixels’ colours into laser parameter settings. Optical and morphological periodic surface structures are also produced by an array of oxide spots and then analysed. Two colours have been coded into one field and the dependencies of the reflected colours on incident and azimuthal angles of the light are discussed. The findings are of interest to a range of application areas, as they can be used to imprint optical devices such as diffusers and Fresnel lenses on metallic surfaces as well as for colour marking.

  13. Laser induced single spot oxidation of titanium

    International Nuclear Information System (INIS)

    Jwad, Tahseen; Deng, Sunan; Butt, Haider; Dimov, S.

    2016-01-01

    Highlights: • A new high resolution laser induced oxidation (colouring) method is proposed (single spot oxidation). • The method is applied to control oxide films thicknesses and hence colours on titanium substrates in micro-scale. • The method enable imprinting high resolution coloured image on Ti substrate. • Optical and morphological periodic surface structures are also produced by an array of oxide spots using the proposed method. • Colour coding of two colours into one field is presented. - Abstract: Titanium oxides have a wide range of applications in industry, and they can be formed on pure titanium using different methods. Laser-induced oxidation is one of the most reliable methods due to its controllability and selectivity. Colour marking is one of the main applications of the oxidation process. However, the colourizing process based on laser scanning strategies is limited by the relative large processing area in comparison to the beam size. Single spot oxidation of titanium substrates is proposed in this research in order to increase the resolution of the processed area and also to address the requirements of potential new applications. The method is applied to produce oxide films with different thicknesses and hence colours on titanium substrates. High resolution colour image is imprinted on a sheet of pure titanium by converting its pixels’ colours into laser parameter settings. Optical and morphological periodic surface structures are also produced by an array of oxide spots and then analysed. Two colours have been coded into one field and the dependencies of the reflected colours on incident and azimuthal angles of the light are discussed. The findings are of interest to a range of application areas, as they can be used to imprint optical devices such as diffusers and Fresnel lenses on metallic surfaces as well as for colour marking.

  14. Hyperspectral laser-induced autofluorescence imaging of dental caries

    Science.gov (United States)

    Bürmen, Miran; Fidler, Aleš; Pernuš, Franjo; Likar, Boštjan

    2012-01-01

    Dental caries is a disease characterized by demineralization of enamel crystals leading to the penetration of bacteria into the dentine and pulp. Early detection of enamel demineralization resulting in increased enamel porosity, commonly known as white spots, is a difficult diagnostic task. Laser induced autofluorescence was shown to be a useful method for early detection of demineralization. The existing studies involved either a single point spectroscopic measurements or imaging at a single spectral band. In the case of spectroscopic measurements, very little or no spatial information is acquired and the measured autofluorescence signal strongly depends on the position and orientation of the probe. On the other hand, single-band spectral imaging can be substantially affected by local spectral artefacts. Such effects can significantly interfere with automated methods for detection of early caries lesions. In contrast, hyperspectral imaging effectively combines the spatial information of imaging methods with the spectral information of spectroscopic methods providing excellent basis for development of robust and reliable algorithms for automated classification and analysis of hard dental tissues. In this paper, we employ 405 nm laser excitation of natural caries lesions. The fluorescence signal is acquired by a state-of-the-art hyperspectral imaging system consisting of a high-resolution acousto-optic tunable filter (AOTF) and a highly sensitive Scientific CMOS camera in the spectral range from 550 nm to 800 nm. The results are compared to the contrast obtained by near-infrared hyperspectral imaging technique employed in the existing studies on early detection of dental caries.

  15. Optimization of laser-induced breakdown spectroscopy for coal powder analysis with different particle flow diameters

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Shunchun, E-mail: epscyao@scut.edu.cn [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China); State Key Laboratory of Pulsed Power Laser Technology, Electronic Engineering Institute, Hefei 230037 (China); Xu, Jialong; Dong, Xuan; Zhang, Bo; Zheng, Jianping [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China); Lu, Jidong, E-mail: jdlu@scut.edu.cn [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China)

    2015-08-01

    The on-line measurement of coal is extremely useful for emission control and combustion process optimization in coal-fired plant. Laser-induced breakdown spectroscopy was employed to directly analyze coal particle flow. A set of tapered tubes were proposed for beam-focusing the coal particle flow to different diameters. For optimizing the measurement of coal particle flow, the characteristics of laser-induced plasma, including optical breakdown, the relative standard deviation of repeated measurement, partial breakdown spectra ratio and line intensity, were carefully analyzed. The comparison of the plasma characteristics among coal particle flow with different diameters showed that air breakdown and the random change in plasma position relative to the collection optics could significantly influence on the line intensity and the reproducibility of measurement. It is demonstrated that the tapered tube with a diameter of 5.5 mm was particularly useful to enrich the coal particles in laser focus spot as well as to reduce the influence of air breakdown and random changes of plasma in the experiment. - Highlights: • Tapered tube was designed for beam-focusing the coal particle flow as well as enriching the particles in laser focus spot. • The characteristics of laser-induced plasma of coal particle flow were investigated carefully. • An appropriate diameter of coal particle flow was proven to benefit for improving the performance of LIBS measurement.

  16. Remote metal analysis by laser induced breakdown spectroscopy

    International Nuclear Information System (INIS)

    Duckworth, A.

    1996-01-01

    This paper describes a new technique by which the composition of irradiated or inaccessible reactor components can be determined remotely. The technique uses very short duration, high energy laser pulses at a wavelength which can be transmitted down an optical fibre to ablate a tiny plasma from the surface of a metal component. Light from the plasma is collected by a second fibre and returned to a spectrometer where it is split into the characteristic emission wavelengths of the elements in the sample. Comparison of the emission line amplitude for a particular element with that of a chosen calibration line can be used to deduce the concentration of the element in the sample. The technique has been used successfully to differentiate between different highly radioactive control rod batches at Sizewell ''A'' and Hinkley Point ''A'' Power Stations. The material analysis accuracy is comparable with that obtained from electron microphobe analysis and other direct spectroscopic methods. However, by analysing the mild steel control rod casing material remotely, difficult sample removal becomes unneccessary and the integrity of the component remains essentially unaltered. In addition, removal of deposits or surface corrosion is incorporated very neatly into the process. These factors make remote laser induced breakdown spectroscopy an ideal tool for material analysis in the nuclear environment. (UK)

  17. Analysis of human nails by laser-induced breakdown spectroscopy

    Science.gov (United States)

    Hosseinimakarem, Zahra; Tavassoli, Seyed Hassan

    2011-05-01

    Laser-induced breakdown spectroscopy (LIBS) is applied to analyze human fingernails using nanosecond laser pulses. Measurements on 45 nail samples are carried out and 14 key species are identified. The elements detected with the present system are: Al, C, Ca, Fe, H, K, Mg, N, Na, O, Si, Sr, Ti as well as CN molecule. Sixty three emission lines have been identified in the spectrum that are dominated by calcium lines. A discriminant function analysis is used to discriminate among different genders and age groups. This analysis demonstrates efficient discrimination among these groups. The mean concentration of each element is compared between different groups. Correlation between concentrations of elements in fingernails is calculated. A strong correlation is found between sodium and potassium while calcium and magnesium levels are inversely correlated. A case report on high levels of sodium and potassium in patients with hyperthyroidism is presented. It is shown that LIBS could be a promising technique for the analysis of nails and therefore identification of health problems.

  18. Laser-Induced Breakdown Spectroscopy of Cinematographic Film

    Science.gov (United States)

    Oujja, M.; Abrusci, C.; Gaspard, S.; Rebollar, E.; Amo, A. del; Catalina, F.; Castillejo, M.

    Laser-induced breakdown spectroscopy (LIBS) was used to characterize the composition of black-and-white, silver-gelatine photographic films. LIB spectra of samples and reference gelatine (of various gel strengths, Bloom values 225 and 75 and crosslinking degrees) were acquired in vacuum by excitation at 266 nm. The elemental composition of the gelatine used in the upper protective layer and in the underlying emulsion is revealed by the stratigraphic analysis carried out by delivering successive pulses on the same spot of the sample. Silver (Ag) lines from the light-sensitive silver halide salts are accompanied by iron, lead and chrome lines. Fe and Pb are constituents of film developers and Cr is included in the hardening agent. The results demonstrate the analytical capacity of LIBS for study and classification of different gelatine types and the sensitivity of the technique to minor changes in gelatine composition. In addition LIBS analysis allows extracting important information on the chemicals used as developers and hardeners of archival cinematographic films.

  19. Nanosecond-laser induced crosstalk of CMOS image sensor

    Science.gov (United States)

    Zhu, Rongzhen; Wang, Yanbin; Chen, Qianrong; Zhou, Xuanfeng; Ren, Guangsen; Cui, Longfei; Li, Hua; Hao, Daoliang

    2018-02-01

    The CMOS Image Sensor (CIS) is photoelectricity image device which focused the photosensitive array, amplifier, A/D transfer, storage, DSP, computer interface circuit on the same silicon substrate[1]. It has low power consumption, high integration,low cost etc. With large scale integrated circuit technology progress, the noise suppression level of CIS is enhanced unceasingly, and its image quality is getting better and better. It has been in the security monitoring, biometrice, detection and imaging and even military reconnaissance and other field is widely used. CIS is easily disturbed and damaged while it is irradiated by laser. It is of great significance to study the effect of laser irradiation on optoelectronic countermeasure and device for the laser strengthening resistance is of great significance. There are some researchers have studied the laser induced disturbed and damaged of CIS. They focused on the saturation, supersaturated effects, and they observed different effects as for unsaturation, saturation, supersaturated, allsaturated and pixel flip etc. This paper research 1064nm laser interference effect in a typical before type CMOS, and observring the saturated crosstalk and half the crosstalk line. This paper extracted from cmos devices working principle and signal detection methods such as the Angle of the formation mechanism of the crosstalk line phenomenon are analyzed.

  20. A comparative study of the laser induce breakdown spectroscopy in single- and double-pulse laser geometry

    International Nuclear Information System (INIS)

    Sun Duixiong; Su Maogen; Dong Chenzhong; Wen Guanhong; Cao Xiangnian

    2013-01-01

    A time resolved laser induced breakdown spectroscopy technique (LIBS) was used for the investigation of emission signal enhancement on double-pulse LIBS. Two Q-switched Nd:YAG lasers at 1064 nm wavelength have been employed to generate laser-induced plasma on aluminium-based alloys. The plasma emission signals were recorded by spectrometer with ICCD detector. Spectral response calibration was performed by using deuterium and tungsten halogen lamps. Time evolution of the plasma temperature and electron density was investigated in SP and DP experiments. Based on the investigation of plasma parameters, the enhancements of emission line intensities were investigated, and the mechanisms of it were discussed. (author)

  1. Railgun system using a laser-induced plasma armature

    International Nuclear Information System (INIS)

    Onozuka, M.; Oda, Y.; Azuma, K.

    1996-01-01

    Development of an electromagnetic railgun system that utilizes a laser-induced plasma armature formation has been conducted to investigate the application of the railgun system for high-speed pellet injection into fusion plasmas. Using the laser-induced plasma formation technique, the required breakdown voltage was reduced by one-tenth compared with that for the spark-discharged plasma. The railgun system successfully accelerated the laser-induced plasma armature by an electromagnetic force that accelerated the pellet. The highest velocity of the solid hydrogen pellets, obtained so far, was 2.6 km/sec using a 2m-long railgun. copyright 1996 American Institute of Physics

  2. Railgun system using a laser-induced plasma armature

    Science.gov (United States)

    Onozuka, Masanori; Oda, Yasushi; Azuma, Kingo

    1996-05-01

    Development of an electromagnetic railgun system that utilizes a laser-induced plasma armature formation has been conducted to investigate the application of the railgun system for high-speed pellet injection into fusion plasmas. Using the laser-induced plasma formation technique, the required breakdown voltage was reduced by one-tenth compared with that for the spark-discharged plasma. The railgun system successfully accelerated the laser-induced plasma armature by an electromagnetic force that accelerated the pellet. The highest velocity of the solid hydrogen pellets, obtained so far, was 2.6 km/sec using a 2m-long railgun.

  3. Railgun system using a laser-induced plasma armature

    Energy Technology Data Exchange (ETDEWEB)

    Onozuka, M.; Oda, Y.; Azuma, K. [Mitsubishi Heavy Industries, Ltd., 3-3-1, Minatomirai, Nishi-ku, Yokohama 220-84 (Japan)

    1996-05-01

    Development of an electromagnetic railgun system that utilizes a laser-induced plasma armature formation has been conducted to investigate the application of the railgun system for high-speed pellet injection into fusion plasmas. Using the laser-induced plasma formation technique, the required breakdown voltage was reduced by one-tenth compared with that for the spark-discharged plasma. The railgun system successfully accelerated the laser-induced plasma armature by an electromagnetic force that accelerated the pellet. The highest velocity of the solid hydrogen pellets, obtained so far, was 2.6 km/sec using a 2m-long railgun. {copyright} {ital 1996 American Institute of Physics.}

  4. Dual-wavelength differential spectroscopic imaging for diagnostics of laser-induced plasma

    Energy Technology Data Exchange (ETDEWEB)

    Motto-Ros, V., E-mail: vincent.motto-ros@univ-lyon1.fr [Universite de Lyon, F-69622, Lyon, Universite Lyon 1, Villeurbanne, CNRS, UMR5579, LASIM (France); Ma, Q.L. [Universite de Lyon, F-69622, Lyon, Universite Lyon 1, Villeurbanne, CNRS, UMR5579, LASIM (France); Gregoire, S. [CRITT Matriaux Alsace, 19 rue de St Junien, 67300 Schiltigheim (France); Lei, W.Q.; Wang, X.C. [Universite de Lyon, F-69622, Lyon, Universite Lyon 1, Villeurbanne, CNRS, UMR5579, LASIM (France); Pelascini, F.; Surma, F. [CRITT Matriaux Alsace, 19 rue de St Junien, 67300 Schiltigheim (France); Detalle, V. [Laboratoire de Recherche des Monuments Historiques, 29 rue de Paris, 77420 Champs-sur-Marne (France); Yu, J. [Universite de Lyon, F-69622, Lyon, Universite Lyon 1, Villeurbanne, CNRS, UMR5579, LASIM (France)

    2012-08-15

    A specific configuration for plasma fast spectroscopic imaging was developed, where a pair of narrowband filters, one fitting an emission line of a species to be studied and the other out of its emission line, allowed double images to be taken for a laser-induced plasma. A dedicated software was developed for the subtraction between the double images. The result represents therefore the monochromatic emission image of the species in the plasma. We have shown in this work that such configuration is especially efficient for the monitoring of a plasma generated under the atmospheric pressure at very short delays after the impact of the laser pulse on the target, when a strong continuum emission is observed. The efficiency of the technique has been particularly demonstrated in the study of laser-induced plasma on a polymer target. Molecular species, such as C{sub 2} and CN, as well as atomic species, such as C and N, were imaged starting from 50 ns after the laser impact. Moreover space segregation of different species, atomic or molecular, inside of the plasma was clearly observed. - Highlights: Black-Right-Pointing-Pointer Imaging to study species with time and space resolution in laser induced plasma. Black-Right-Pointing-Pointer Image display of multiple species is proposed based on RGB color model. Black-Right-Pointing-Pointer Molecular emission (CN and C{sub 2}) is observed at very short delays (50 ns). Black-Right-Pointing-Pointer Segregation of different species inside the plasma is clearly established.

  5. Non-destructive evaluation of UV pulse laser-induced damage performance of fused silica optics.

    Science.gov (United States)

    Huang, Jin; Wang, Fengrui; Liu, Hongjie; Geng, Feng; Jiang, Xiaodong; Sun, Laixi; Ye, Xin; Li, Qingzhi; Wu, Weidong; Zheng, Wanguo; Sun, Dunlu

    2017-11-24

    The surface laser damage performance of fused silica optics is related to the distribution of surface defects. In this study, we used chemical etching assisted by ultrasound and magnetorheological finishing to modify defect distribution in a fused silica surface, resulting in fused silica samples with different laser damage performance. Non-destructive test methods such as UV laser-induced fluorescence imaging and photo-thermal deflection were used to characterize the surface defects that contribute to the absorption of UV laser radiation. Our results indicate that the two methods can quantitatively distinguish differences in the distribution of absorptive defects in fused silica samples subjected to different post-processing steps. The percentage of fluorescence defects and the weak absorption coefficient were strongly related to the damage threshold and damage density of fused silica optics, as confirmed by the correlation curves built from statistical analysis of experimental data. The results show that non-destructive evaluation methods such as laser-induced fluorescence and photo-thermal absorption can be effectively applied to estimate the damage performance of fused silica optics at 351 nm pulse laser radiation. This indirect evaluation method is effective for laser damage performance assessment of fused silica optics prior to utilization.

  6. Laser-induced fusion of human embryonic stem cells with optical tweezers

    Energy Technology Data Exchange (ETDEWEB)

    Chen Shuxun; Wang Xiaolin; Sun Dong [Department of Mechanical and Biomedical Engineering, City University of Hong Kong (Hong Kong); Cheng Jinping; Han Cheng, Shuk [Department of Biology and Chemistry, City University of Hong Kong (Hong Kong); Kong, Chi-Wing [Stem Cell and Regenerative Medicine Consortium, and Departments of Medicine and Physiology, LKS Faculty of Medicine, University of Hong Kong (Hong Kong); Li, Ronald A. [Stem Cell and Regenerative Medicine Consortium, and Departments of Medicine and Physiology, LKS Faculty of Medicine, University of Hong Kong (Hong Kong); Center of Cardiovascular Research, Mount Sinai School of Medicine, New York, New York 10029 (United States)

    2013-07-15

    We report a study on the laser-induced fusion of human embryonic stem cells (hESCs) at the single-cell level. Cells were manipulated by optical tweezers and fused under irradiation with pulsed UV laser at 355 nm. Successful fusion was indicated by green fluorescence protein transfer. The influence of laser pulse energy on the fusion efficiency was investigated. The fused products were viable as gauged by live cell staining. Successful fusion of hESCs with somatic cells was also demonstrated. The reported fusion outcome may facilitate studies of cell differentiation, maturation, and reprogramming.

  7. Picosecond wide-field time-correlated single photon counting fluorescence microscopy with a delay line anode detector

    Energy Technology Data Exchange (ETDEWEB)

    Hirvonen, Liisa M.; Le Marois, Alix; Suhling, Klaus, E-mail: klaus.suhling@kcl.ac.uk [Department of Physics, King' s College London, Strand, London WC2R 2LS (United Kingdom); Becker, Wolfgang; Smietana, Stefan [Becker & Hickl GmbH, Nahmitzer Damm 30, 12277 Berlin (Germany); Milnes, James; Conneely, Thomas [Photek Ltd., 26 Castleham Rd, Saint Leonards-on-Sea TN38 9NS (United Kingdom); Jagutzki, Ottmar [Institut für Kernphysik, Max-von-Laue-Str. 1, 60438 Frankfurt (Germany)

    2016-08-15

    We perform wide-field time-correlated single photon counting-based fluorescence lifetime imaging (FLIM) with a crossed delay line anode image intensifier, where the pulse propagation time yields the photon position. This microchannel plate-based detector was read out with conventional fast timing electronics and mounted on a fluorescence microscope with total internal reflection (TIR) illumination. The picosecond time resolution of this detection system combines low illumination intensity of microwatts with wide-field data collection. This is ideal for fluorescence lifetime imaging of cell membranes using TIR. We show that fluorescence lifetime images of living HeLa cells stained with membrane dye di-4-ANEPPDHQ exhibit a reduced lifetime near the coverslip in TIR compared to epifluorescence FLIM.

  8. Laser-induced nuclear physics and applications

    International Nuclear Information System (INIS)

    Ledingham, K.W.D.; Singhal, R.P.; McKenna, P.; Spencer, I.

    2002-01-01

    With a 1 ps pulse laser at 1 μm wavelength, He gas is ionised at about 3.10 14 W.cm -2 . As the intensity increases, the inert gases become multiple ionised and between 10 18 and 10 19 W.cm -2 photon induced nuclear reactions are energetically possible. Close to 10 21 W.cm -2 pion production can take place. At the very high intensities of 10 28 W.cm -2 , it can be shown that electron-positron pairs can be created from the vacuum. The authors review the applications of high intensity focused laser beams in particle acceleration, laser-induced fission and laser production of protons and neutrons. Exciting new phenomena are expected at intensities higher than 10 22 W.cm -2 , -) the oscillating electric field can affect directly the protons in exactly the same way as the electrons in the plasma, -) fusion reactions by direct laser acceleration of ions. (A.C.)

  9. Volume of a laser-induced microjet

    Science.gov (United States)

    Kawamoto, Sennosuke; Hayasaka, Keisuke; Noguchi, Yuto; Tagawa, Yoshiyuki

    2015-11-01

    Needle-free injection systems are of great importance for medical treatments. In spite of their great potential, these systems are not commonly used. One of the common problems is strong pain caused by diffusion shape of the jet. To solve this problem, the usage of a high-speed highly-focused microjet as needle-free injection system is expected. It is thus crucial to control important indicators such as ejected volume of the jet for its safe application. We conduct experiments to reveal which parameter influences mostly the ejected volume. In the experiments, we use a glass tube of an inner diameter of 500 micro-meter, which is filled with the liquid. One end is connected to a syringe and the other end is opened. Radiating the pulse laser instantaneously vapors the liquid, followed by the generation of a shockwave. We find that the maximum volume of a laser-induced bubble is approximately proportional to the ejected volume. It is also found that the occurrence of cavitation does not affect the ejected volume while it changes the jet velocity.

  10. Medical Applications of Laser Induced Breakdown Spectroscopy

    International Nuclear Information System (INIS)

    Pathak, A K; Rai, N K; Singh, Ankita; Rai, A K; Rai, Pradeep K; Rai, Pramod K

    2014-01-01

    Sedentary lifestyle of human beings has resulted in various diseases and in turn we require a potential tool that can be used to address various issues related to human health. Laser Induced Breakdown Spectroscopy (LIBS) is one such potential optical analytical tool that has become quite popular because of its distinctive features that include applicability to any type/phase of samples with almost no sample preparation. Several reports are available that discusses the capabilities of LIBS, suitable for various applications in different branches of science which cannot be addressed by traditional analytical methods but only few reports are available for the medical applications of LIBS. In the present work, LIBS has been implemented to understand the role of various elements in the formation of gallstones (formed under the empyema and mucocele state of gallbladder) samples along with patient history that were collected from Purvancal region of Uttar Pradesh, India. The occurrence statistics of gallstones under the present study reveal higher occurrence of gallstones in female patients. The gallstone occurrence was found more prevalent for those male patients who were having the habit of either tobacco chewing, smoking or drinking alcohols. This work further reports in-situ LIBS study of deciduous tooth and in-vivo LIBS study of human nail

  11. Flexible temperature and flow sensor from laser-induced graphene

    KAUST Repository

    Marengo, Marco; Marinaro, Giovanni; Kosel, Jü rgen

    2017-01-01

    Herein we present a flexible temperature sensor and a flow speed sensor based on laser-induced graphene. The main benefits arise from peculiar electrical, thermal and mechanical performances of the material thus obtained, along with a cheap

  12. Neuroprotective Treatment of Laser-Induced Retinal Injuries

    National Research Council Canada - National Science Library

    Rosner, Mordechai

    2001-01-01

    .... It is not possible to prevent all these injuries and there is no treatment. This study was designed to evaluate the neuroprotective effect of dextromethorphan, memantine and brimonidine in our rat model of laser- induced retinal-lesions Methods...

  13. Production and Characterization of Femtosecond-Laser-Induced Air Plasma

    National Research Council Canada - National Science Library

    Armbruster, David R

    2008-01-01

    .... A beam expander was used to expand the beam to a diameter of approximately 6.5 mm, and the beam was focused through a 25 mm focal length achromatic lens to produce laser-induced plasma in ambient air...

  14. Laser-induced shockwave propagation from ablation in a cavity

    International Nuclear Information System (INIS)

    Zeng Xianzhong; Mao Xianglei; Mao, Samuel S.; Wen, S.-B.; Greif, Ralph; Russo, Richard E.

    2006-01-01

    The propagation of laser-induced shockwaves from ablation inside of cavities was determined from time-resolved shadowgraph images. The temperature and electron number density of the laser-induced plasma was determined from spectroscopic measurements. These properties were compared to those for laser ablation on the flat surface under the same energy and background gas condition. A theoretical model was proposed to determine the amount of energy and vaporized mass stored in the vapor plume based on these measurements

  15. Spectroscopic analysis of femtosecond laser-induced gas breakdown

    International Nuclear Information System (INIS)

    Hermann, J.; Bruneau, S.; Sentis, M.

    2004-01-01

    The plasma generated by the interaction of a femtosecond laser pulse with gas has been analyzed using time- and space-resolved emission spectroscopy. The laser beam has been focused with a microscope objective into different gases (air, Ar, He) at pressures ranging from 10 2 to 10 5 Pa. From the analysis of spectral line emission from ions and neutral atoms, the plasma parameters and the plasma composition have been determined as a function of time and space. Furthermore, the generation of fast electrons and/or VUV radiation by the femtosecond laser interaction with the gas was brought to the fore. From the time- and space-evolution of the plasma parameters, a rough estimation of initial values of electron density and refraction index in the focal volume has been performed. These results are compared to analysis of the laser beam transmitted by the plasma. The latter show that only a small fraction of the laser energy is absorbed by the plasma while the spatial distribution of the transmitted laser beam is strongly perturbed by the plasma, which acts like a defocusing lens. However, in ambient helium, the plasma defocusing is weak due to the high ionization potential of helium. The understanding of femtosecond laser-induced gas breakdown is useful for process optimization in femtosecond laser applications like micromachining or surface microanalysis, etc

  16. Aluminum alloy analysis using microchip-laser induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Freedman, Andrew [Center for Sensor Systems and Technologies, Aerodyne Research, Inc., 45 Manning Road Billerica, MA, 01821-3976 (United States)]. E-mail: af@aerodyne.com; Iannarilli, Frank J. [Center for Sensor Systems and Technologies, Aerodyne Research, Inc., 45 Manning Road Billerica, MA, 01821-3976 (United States); Wormhoudt, Joda C. [Center for Sensor Systems and Technologies, Aerodyne Research, Inc., 45 Manning Road Billerica, MA, 01821-3976 (United States)

    2005-08-31

    A laser induced breakdown spectroscopy-based apparatus for the analysis of aluminum alloys which employs a microchip laser and a handheld spectrometer with an ungated, non-intensified CCD array has been built and tested. The microchip laser, which emits low energy pulses (4-15 {mu}J) at high repetition rates (1-10 kHz) at 1064 nm, produces, when focused, an ablation crater with a radius on the order of only 10 {mu}m. The resulting emission is focused onto an optical fiber connected to 0.10 m focal length spectrometer with a spectral range of 275-413 nm. The apparatus was tested using 30 different aluminum alloy reference samples. Two techniques for constructing calibration curves from the data, peak integration and partial least squares regression, were quantitatively evaluated. Results for Fe, Mg, Mn, Ni, Si, and Zn indicated limits of detection (LOD) that ranged from 0.05 to 0.14 wt.% and overall measurement errors which varied from 0.06 to 0.18 wt.%. Higher limits of detection and overall error for Cu (> 0.3 wt.%) were attributed to analysis problems associated with the presence of optically thick lines and a spectral interference from Zn. Improvements in design and component sensitivity should increase overall performance by at least a factor of 2, allowing for dependable aluminum alloy classification.

  17. Remote metal analysis by laser induced breakdown spectroscopy

    International Nuclear Information System (INIS)

    Duckworth, A.

    1996-01-01

    This paper describes a new technique by which the composition of irradiated or inaccessible reactor components can be determined remotely. The technique uses very short duration, high energy laser pulses at a wavelength which can be transmitted down an optical fibre to ablate a tiny plasma from the surface of a metal component. Light from the plasma is collected by a second fibre and returned to a spectrometer where it is split into the characteristic emission wavelengths of the elements in the sample. Comparison of the emission line amplitude for a particular element with that of a chosen calibrationline can be used to deduce the concentration of the element in the sample. The technique has been used successfully to differentiate between highly radioactive control rod batches at Sizewell 'A' and Hinkley Point 'A Power Stations. The material analysis accuracy is comparable with that obtained from electron microprobe analysis and other direct spectroscopic methods. However, by analysing the mild steel control rod casing material remotely, difficult sample removal becomes unnecessary and the integrity of the component remains essentially unaltered. In addition, removal of deposits or surface corrosion is incorporated very neatly into the process. These factors make remote laser induced breakdown spectroscopy an ideal tool for material analysis in the nuclear environment. (Author)

  18. An experimental investigation on the properties of laser-induced plasma emission spectra

    International Nuclear Information System (INIS)

    Tang Xiaoshuan; Li Chunyan; Ji Xuehan; Feng Eryin; Cui Zhifeng

    2004-01-01

    The authors have measured the time-resolved emission spectra produced by Nd: YAG laser induced Al plasma with different kinds of buffer gas (He, Ar, N 2 and Air). The dependence of emission spectra line intensity and Stark broadening on the time delay, kinds and pressure of buffer gas are studied. The results show that the atomic emission line intensity reaches maximum at 3 μs time delay, the Stark broadening increases with increasing the pressure of buffer gas, and decreases with increasing time delay. The Stark broadening in Ar buffer gas is largest among the four different kinds of buffer gas. (author)

  19. Impurity diagnosis of a KSTAR graphite divertor tile using laser induced breakdown spectroscopy technique

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Minju; Cho, Min Sang; Cho, Byoung Ick, E-mail: bicho@gist.ac.kr

    2017-04-15

    Laser induced breakdown spectroscopy (LIBS) has been tested to diagnose impurity elements on a Korea Superconducting Tokamak Advanced Research (KSTAR) divertor tile. Spectral lines of various impurity elements such as iron, chromium, and nickel were detected from the divertor surface. The variation of spectra with consecutive laser pulses demonstrates the potential for depth profiling analysis for the deposited impurity layer. The LIBS plasma parameters have been qualitatively determined from analysis of the relative line intensities and linewidths for each element. The validity of this analysis has been checked with atomic spectral simulations.

  20. Laser-induced selective copper plating of polypropylene surface

    Science.gov (United States)

    Ratautas, K.; Gedvilas, M.; Stankevičiene, I.; JagminienÄ--, A.; Norkus, E.; Li Pira, N.; Sinopoli, S.; Emanuele, U.; Račiukaitis, G.

    2016-03-01

    Laser writing for selective plating of electro-conductive lines for electronics has several significant advantages, compared to conventional printed circuit board technology. Firstly, this method is faster and cheaper at the prototyping stage. Secondly, material consumption is reduced, because it works selectively. However, the biggest merit of this method is potentiality to produce moulded interconnect device, enabling to create electronics on complex 3D surfaces, thus saving space, materials and cost of production. There are two basic techniques of laser writing for selective plating on plastics: the laser-induced selective activation (LISA) and laser direct structuring (LDS). In the LISA method, pure plastics without any dopant (filler) can be used. In the LDS method, special fillers are mixed in the polymer matrix. These fillers are activated during laser writing process, and, in the next processing step, the laser modified area can be selectively plated with metals. In this work, both methods of the laser writing for the selective plating of polymers were investigated and compared. For LDS approach, new material: polypropylene with carbon-based additives was tested using picosecond and nanosecond laser pulses. Different laser processing parameters (laser pulse energy, scanning speed, the number of scans, pulse durations, wavelength and overlapping of scanned lines) were applied in order to find out the optimal regime of activation. Areal selectivity tests showed a high plating resolution. The narrowest width of a copper-plated line was less than 23 μm. Finally, our material was applied to the prototype of the electronic circuit board on a 2D surface.

  1. Liquid steel analysis by laser-induced plasma spectroscopy

    International Nuclear Information System (INIS)

    Gruber, J.

    2002-11-01

    When a nanosecond pulsed laser is focused onto a sample and the intensity exceeds a certain threshold, material is vaporized and a plasma is formed above the sample surface. The laser-light becomes increasingly absorbed by inverse bremsstrahlung and by photo-excitation and photo-ionization of atoms and molecules. The positive feedback, by which the number of energetic electrons for ionization is increased in an avalanche-like manner under the influence of laser-light, is the so-called optical breakdown. Radiating excited atoms and ions within the expanding plasma plume produce a characteristic optical emission spectrum. A spectroscopic analysis of this optical emission of the laser-induced plasma permits a qualitative and quantitative chemical analysis of the investigated sample. This technique is therefore often called laser-induced plasma spectroscopy (LIPS) or laser-induced breakdown spectroscopy (LIBS). LIPS is a fast non-contact technique, by which solid, liquid or gaseous samples can be analyzed with respect to their chemical composition. Hence, it is an appropriate tool for the rapid in-situ analysis of not easily accessible surfaces for process control in industrial environments. In this work, LIPS was studied as a technique to determine the chemical composition of solid and liquid steel. A LIPS set-up was designed and built for the remote and continuous in-situ analysis of the steel melt. Calibration curves were prepared for the LIPS analysis of Cr, Mn, Ni and Cu in solid steel using reference samples with known composition. In laboratory experiments an induction furnace was used to melt steel samples in crucibles, which were placed at a working distance of 1.5 m away from the LIPS apparatus. The response of the LIPS system was monitored on-line during the addition of pure elements to the liquid steel bath within certain concentration ranges (Cr: 0.11 - 13.8 wt%, Cu: 0.044 - 0.54 wt%, Mn: 1.38 - 2.5 wt%, Ni: 0.049 - 5.92 wt%). The analysis of an element

  2. Fluorescent H{sub 2} Emission Lines from the Reflection Nebula NGC 7023 Observed with IGRINS

    Energy Technology Data Exchange (ETDEWEB)

    Le, Huynh Anh N.; Pak, Soojong; Lee, Hye-In [School of Space Research, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 17104 (Korea, Republic of); Kaplan, Kyle; Mace, Gregory; Pavel, Michael; Jaffe, Daniel T. [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Lee, Sungho; Jeong, Ueejeong; Chun, Moo-Young; Yuk, In-Soo; Hwang, Narae; Kim, Kang-Min; Park, Chan; Oh, Jae Sok; Yu, Young Sam; Park, Byeong-Gon; Minh, Young Chol [Korea Astronomy and Space Science Institute, Daejeon 34055 (Korea, Republic of); Oh, Heeyoung [Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826 (Korea, Republic of); Pyo, Tae-Soo, E-mail: huynhanh7@khu.ac.kr, E-mail: soojong@khu.ac.kr [Subaru Telescope, National Astronomical Observatory of Japan, National Institutes of Natural Sciences (NINS), 650 North Aohoku Place, Hilo, HI 96720 (United States)

    2017-05-20

    We have analyzed the temperature, velocity, and density of H{sub 2} gas in NGC 7023 with a high-resolution near-infrared spectrum of the northwestern filament of the reflection nebula. By observing NGC 7023 in the H and K bands at R ≃ 45,000 with the Immersion GRating INfrared Spectrograph, we detected 68 H{sub 2} emission lines within the 1″ × 15″ slit. The diagnostic ratio of 2-1 S(1)/1-0 S(1) is 0.41−0.56. In addition, the estimated ortho-to-para ratio (OPR) is 1.63−1.82, indicating that the H{sub 2} emission transitions in the observed region arise mostly from gas excited by UV fluorescence. Gradients in the temperature, velocity, and OPR within the observed area imply motion of the photodissociation region (PDR) relative to the molecular cloud. In addition, we derive the column density of H{sub 2} from the observed emission lines and compare these results with PDR models in the literature covering a range of densities and incident UV field intensities. The notable difference between PDR model predictions and the observed data, in high rotational J levels of ν = 1, is that the predicted formation temperature for newly formed H{sub 2} should be lower than that of the model predictions. To investigate the density distribution, we combine pixels in 1″ × 1″ areas and derive the density distribution at the 0.002 pc scale. The derived gradient of density suggests that NGC 7023 has a clumpy structure, including a high clump density of ∼10{sup 5} cm{sup −3} with a size smaller than ∼5 × 10{sup −3} pc embedded in lower-density regions of 10{sup 3}–10{sup 4} cm{sup −3}.

  3. Tumorigenicity and Validity of Fluorescence Labelled Mesenchymal and Epithelial Human Oral Cancer Cell Lines in Nude Mice

    Directory of Open Access Journals (Sweden)

    Wei Xin Cai

    2016-01-01

    Full Text Available Tumorigenicity and metastatic activity can be visually monitored in cancer cells that were labelled with stable fluorescence. The aim was to establish and validate local and distant spread of subcutaneously previously injected fluorescence transduced human tongue cancer cell lines of epithelial and mesenchymal phenotype in nude mice. A total of 32 four-week-old male athymic Balb/c nude mice were randomly allocated into 4 groups (n=8. A single dose of 0.3 mL PBS containing 1 × 107 of four different cancer cell-lines (UM1, UM1-GFP, UM2, and UM2-RFP was injected subcutaneously into the right side of their posterolateral back. Validity assessment of the labelled cancer cells’ tumorigenicity was assessed by physical examination, imaging, and histology four weeks after the injection. The tumor take rate of cancer cells was similar in animals injected with either parental or transduced cancer cells. Transduced cancer cells in mice were easily detectable in vivo and after cryosection using fluorescent imaging. UM1 cells showed increased tumor take rate and mean tumor volume, presenting with disorganized histopathological patterns. Fluorescence labelled epithelial and mesenchymal human tongue cancer cell lines do not change in tumorigenicity or cell phenotype after injection in vivo.

  4. Metal surface nitriding by laser induced plasma

    Science.gov (United States)

    Thomann, A. L.; Boulmer-Leborgne, C.; Andreazza-Vignolle, C.; Andreazza, P.; Hermann, J.; Blondiaux, G.

    1996-10-01

    We study a nitriding technique of metals by means of laser induced plasma. The synthesized layers are composed of a nitrogen concentration gradient over several μm depth, and are expected to be useful for tribological applications with no adhesion problem. The nitriding method is tested on the synthesis of titanium nitride which is a well-known compound, obtained at present by many deposition and diffusion techniques. In the method of interest, a laser beam is focused on a titanium target in a nitrogen atmosphere, leading to the creation of a plasma over the metal surface. In order to understand the layer formation, it is necessary to characterize the plasma as well as the surface that it has been in contact with. Progressive nitrogen incorporation in the titanium lattice and TiN synthesis are studied by characterizing samples prepared with increasing laser shot number (100-4000). The role of the laser wavelength is also inspected by comparing layers obtained with two kinds of pulsed lasers: a transversal-excited-atmospheric-pressure-CO2 laser (λ=10.6 μm) and a XeCl excimer laser (λ=308 nm). Simulations of the target temperature rise under laser irradiation are performed, which evidence differences in the initial laser/material interaction (material heated thickness, heating time duration, etc.) depending on the laser features (wavelength and pulse time duration). Results from plasma characterization also point out that the plasma composition and propagation mode depend on the laser wavelength. Correlation of these results with those obtained from layer analyses shows at first the important role played by the plasma in the nitrogen incorporation. Its presence is necessary and allows N2 dissociation and a better energy coupling with the target. Second, it appears that the nitrogen diffusion governs the nitriding process. The study of the metal nitriding efficiency, depending on the laser used, allows us to explain the differences observed in the layer features

  5. Lanthanide-based laser-induced phosphorescence for spray diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Voort, D. D. van der, E-mail: d.d.v.d.voort@tue.nl; Water, W. van de; Kunnen, R. P. J.; Clercx, H. J. H.; Heijst, G. J. F. van [Applied Physics Department, Eindhoven University of Technology, 5612 AZ Eindhoven (Netherlands); Maes, N. C. J.; Sweep, A. M.; Dam, N. J. [Mechanical Engineering Department, Eindhoven University of Technology, 5612 AZ Eindhoven (Netherlands); Lamberts, T. [Institute of Theoretical Chemistry, University of Stuttgart, D-70569 Stuttgart (Germany)

    2016-03-15

    Laser-induced phosphorescence (LIP) is a relatively recent and versatile development for studying flow dynamics. This work investigates certain lanthanide-based molecular complexes for their use in LIP for high-speed sprays. Lanthanide complexes in solutions have been shown to possess long phosphorescence lifetimes (∼1-2 ms) and to emit light in the visible wavelength range. In particular, europium and terbium complexes are investigated using fluorescence/phosphorescence spectrometry, showing that europium-thenoyltrifluoracetone-trioctylphosphineoxide (Eu-TTA-TOPO) can be easily and efficiently excited using a standard frequency-tripled Nd:YAG laser. The emitted spectrum, with maximum intensity at a wavelength of 614 nm, is shown not to vary strongly with temperature (293-383 K). The decay constant of the phosphorescence, while independent of ambient pressure, decreases by approximately 12 μs/K between 323 and 373 K, with the base level of the decay constant dependent on the used solvent. The complex does not luminesce in the gas or solid state, meaning only the liquid phase is visualized, even in an evaporating spray. By using an internally excited spray containing the phosphorescent complex, the effect of vaporization is shown through the decrease in measured intensity over the length of the spray, together with droplet size measurements using interferometric particle imaging. This study shows that LIP, using the Eu-TTA-TOPO complex, can be used with different solvents, including diesel surrogates. Furthermore, it can be easily handled and used in sprays to investigate spray breakup and evaporation.

  6. Sensitive elemental detection using microwave-assisted laser-induced breakdown imaging

    Science.gov (United States)

    Iqbal, Adeel; Sun, Zhiwei; Wall, Matthew; Alwahabi, Zeyad T.

    2017-10-01

    This study reports a sensitive spectroscopic method for quantitative elemental detection by manipulating the temporal and spatial parameters of laser-induced plasma. The method was tested for indium detection in solid samples, in which laser ablation was used to generate a tiny plasma. The lifetime of the laser-induced plasma can be extended to hundreds of microseconds using microwave injection to remobilize the electrons. In this novel method, temporal integrated signal of indium emission was significantly enhanced. Meanwhile, the projected detectable area of the excited indium atoms was also significantly improved using an interference-, instead of diffraction-, based technique, achieved by directly imaging microwave-enhanced plasma through a novel narrow-bandpass filter, exactly centered at the indium emission line. Quantitative laser-induce breakdown spectroscopy was also recorded simultaneously with the new imaging method. The intensities recorded from both methods exhibit very good mutual linear relationship. The detection intensity was improved to 14-folds because of the combined improvements in the plasma lifetime and the area of detection.

  7. Time-Resolved Spectroscopy Diagnostic of Laser-Induced Optical Breakdown

    Directory of Open Access Journals (Sweden)

    Christian G. Parigger

    2010-01-01

    Full Text Available Transient laser plasma is generated in laser-induced optical breakdown (LIOB. Here we report experiments conducted with 10.6-micron CO2 laser radiation, and with 1.064-micron fundamental, 0.532-micron frequency-doubled, 0.355-micron frequency-tripled Nd:YAG laser radiation. Characterization of laser induced plasma utilizes laser-induced breakdown spectroscopy (LIBS techniques. Atomic hydrogen Balmer series emissions show electron number density of 1017 cm−3 measured approximately 10 μs and 1 μs after optical breakdown for CO2 and Nd:YAG laser radiation, respectively. Recorded molecular recombination emission spectra of CN and C2 Swan bands indicate an equilibrium temperature in excess of 7000 Kelvin, inferred for these diatomic molecules. Reported are also graphite ablation experiments where we use unfocused laser radiation that is favorable for observation of neutral C3 emission due to reduced C3 cation formation. Our analysis is based on computation of diatomic molecular spectra that includes accurate determination of rotational line strengths, or Hönl-London factors.

  8. High spatial resolution in laser-induced breakdown spectroscopy of expanding plasmas

    International Nuclear Information System (INIS)

    Siegel, J.; Epurescu, G.; Perea, A.; Gordillo-Vazquez, F.J.; Gonzalo, J.; Afonso, C.N.

    2005-01-01

    We report a technique that is able to achieve high spatial resolution in the measurement of the temporal and spectral emission characteristics of laser-induced expanding plasmas. The plasma is imaged directly onto the slit of an imaging spectrograph coupled to a time-gated intensified camera, with the plasma expansion direction being parallel to the slit extension. In this way, a single hybrid detection system is used to acquire the spatial, spectral and temporal characteristics of the laser induced plasma. The parallel acquisition approach of this technique ensures a much better spatial resolution in the expansion direction, reproducibility and data acquisition speed than commonly obtained by sequential measurements at different distances from the target. We have applied this technique to study the laser-induced plasma in LiNbO 3 and Bi 12 Ge 1 O 20 , revealing phenomena not seen in such detail with standard instruments. These include extreme line broadening up to a few nanometers accompanied by self-absorption near the target surface, as well as different ablation and expansion dynamics for the different species ejected. Overall, the high precision and wealth of quantitative information accessible with this technique open up new possibilities for the study of fundamental plasma expansion processes during pulsed laser ablation

  9. Investigating the structural origin of trpzip2 temperature dependent unfolding fluorescence line shape based on a Markov state model simulation.

    Science.gov (United States)

    Song, Jian; Gao, Fang; Cui, Raymond Z; Shuang, Feng; Liang, Wanzhen; Huang, Xuhui; Zhuang, Wei

    2012-10-25

    Vibrationally resolved fluorescence spectra of the β-hairpin trpzip2 peptide at two temperatures as well as during a T-jump unfolding process are simulated on the basis of a combination of Markov state models and quantum chemistry schemes. The broad asymmetric spectral line shape feature is reproduced by considering the exciton-phonon couplings. The temperature dependent red shift observed in the experiment has been attributed to the state population changes of specific chromophores. Through further theoretical study, it is found that both the environment's electric field and the chromophores' geometry distortions are responsible for tryptophan fluorescence shift.

  10. Characterization of cinematographic films by Laser Induced Breakdown Spectroscopy

    International Nuclear Information System (INIS)

    Gaspard, S.; Oujja, M.; Rebollar, E.; Abrusci, C.; Catalina, F.; Castillejo, M.

    2007-01-01

    The emulsion-coated transparent plastic-base film has been the main carrier for production and preservation of motion picture contents since the 19th century. The knowledge of the composition of black and white silver gelatine cinematographic films is of great importance for the characterization of the photographic process and for identifying the optimum conditions for conservation. A cinematographic film is a multi-component system that consists of a layer of photographic emulsion overcoating a polymeric support (plasticized cellulose triacetate) and a protective transparent cross-linked gelatine layer coating the emulsion. In the present work, Laser Induced Breakdown Spectroscopy (LIBS) is used to characterize the composition of the materials of cinematographic films. LIB spectra of film samples and of different individual film components, polymeric support and reference gelatines, were acquired in vacuum by excitation at 266 nm (Q-switched Nd:YAG laser, 6 ns, 10 Hz). In the cinematographic film, silver lines from the light-sensitive silver halide salts of the photographic emulsion are accompanied by iron, lead, chrome and phosphorus lines. Iron and lead are constituents of film developers, chrome is included in the composition of the hardening agents and phosphorus has its origin in the plasticizer used in the polymeric support. By applying successive pulses on the same spot of the film sample, it was possible to observe through stratigraphic analysis the different layers composition. Additionally, the results obtained reveal the analytical capacity of LIBS for the study and classification of the different gelatine types and qualities used for the protecting layer and the photographic emulsion

  11. Laser-excited fluorescence spectroscopy of oxide glasses

    International Nuclear Information System (INIS)

    Weber, M.J.

    1977-01-01

    Laser-induced fluorescence line narrowing was applied to investigate the local fields and interactions of paramagnetic ions in oxide glasses. Studies included the site dependence of energy levels, radiative and nonradiative transition probabilities, homogeneous line broadening, and ion--ion energy transfer of rare earth ions. These results and the experimental techniques are reviewed briefly; the use of paramagnetic ions other than the rare earths is also considered. Recently, laser-excited fluorescence spectroscopy was used to investigate modifications in the local structure of lithium borate glass caused by compositional changes and phase separation and the site dependence of nonradiative relaxation of paramagnetic ions by multiphonon processes. These results and their implications are discussed. 6 figures

  12. Contribution of inner shell Compton ionization to the X-ray fluorescence line intensity

    Science.gov (United States)

    Fernández, Jorge E.; Scot, Viviana; Di Giulio, Eugenio

    2016-10-01

    The Compton effect is a potential ionization mechanism of atoms. It produces vacancies in inner shells that are filled with the same mechanism of atomic relaxation as the one following photo-absorption. This contribution to X-ray fluorescence emission is frequently neglected because the total Compton cross-section is apparently much lower than the photoelectric one at useful X-ray energies. However, a more careful analysis suggests that is necessary to consider single shell cross sections (instead of total cross sections) as a function of energy. In this article these Compton cross sections are computed for the shells K, L1-L3 and M1-M5 in the framework of the impulse approximation. By comparing the Compton and the photoelectric cross-section for each shell it is then possible to determine the extent of the Compton correction to the intensity of the corresponding characteristic lines. It is shown that for the K shell the correction becomes relevant for excitation energies which are too high to be influent in X-ray spectrometry. In contrast, for L and M shells the Compton contribution is relevant for medium-Z elements and medium energies. To illustrate the different grades of relevance of the correction, for each ionized shell, the energies for which the Compton contribution reaches the extent levels of 1, 5, 10, 20, 50 and 100% of the photoelectric one are determined for all the elements with Z = 11-92. For practical applications it is provided a simple formula and fitting coefficients to compute average correction levels for the shells considered.

  13. Free Electron Laser Induced Forward Transfer Method of Biomaterial for Marking

    Science.gov (United States)

    Suzuki, Kaoru

    Biomaterial, such as chitosan, poly lactic acid, etc., containing fluorescence agent was deposited onto biology hard tissue, such as teeth, fingernail of dog or cat, or sapphire substrate by free electron laser induced forward transfer method for direct write marking. Spin-coated biomaterial with fluorescence agent of rhodamin-6G or zinc phthalochyamine target on sapphire plate was ablated by free electron laser (resonance absorption wavelength of biomaterial : 3380 nm). The influence of the spin-coating film-forming temperature on hardness and adhesion strength of biomaterial is particularly studied. Effect of resonance excitation of biomaterial target by turning free electron laser was discussed to damage of biomaterial, rhodamin-6G or zinc phtarochyamine for direct write marking

  14. An investigation of Laser Induced Breakdown Spectroscopy for use as a control in the laser removal of rock from fossils found at the Malapa hominin site, South Africa

    CSIR Research Space (South Africa)

    Roberts, DE

    2012-07-01

    Full Text Available Laser Induced Breakdown Spectroscopy (LIBS) was used to study the spectra from fossils and surrounding rock recovered from the Cradle of Mankind site at Malapa, South Africa. The objective was to find a suitable spectral line(s), specific to fossils...

  15. Comparative Study of Elemental Nutrients in Organic and Conventional Vegetables Using Laser-Induced Breakdown Spectroscopy (LIBS).

    Science.gov (United States)

    Bhatt, Chet R; Alfarraj, Bader; Ghany, Charles T; Yueh, Fang Y; Singh, Jagdish P

    2017-04-01

    In this study, the laser-induced breakdown spectroscopy (LIBS) technique was used to identify and compare the presence of major nutrient elements in organic and conventional vegetables. Different parts of cauliflowers and broccolis were used as working samples. Laser-induced breakdown spectra from these samples were acquired at optimum values of laser energy, gate delay, and gate width. Both univariate and multivariate analyses were performed for the comparison of these organic and conventional vegetable flowers. Principal component analysis (PCA) was taken into account for multivariate analysis while for univariate analysis, the intensity of selected atomic lines of different elements and their intensity ratio with some reference lines of organic cauliflower and broccoli samples were compared with those of conventional ones. In addition, different parts of the cauliflower and broccoli were compared in terms of intensity and intensity ratio of elemental lines.

  16. Laser-induced breakdown spectroscopy analysis of asbestos

    International Nuclear Information System (INIS)

    Caneve, L.; Colao, F.; Fabbri, F.; Fantoni, R.; Spizzichino, V.; Striber, J.

    2005-01-01

    Laser-induced breakdown spectroscopy was applied to test the possibility of detecting and identifying asbestos in different samples in view of the perspective at field operation without sample preparation which is peculiar to this technique. Several like-resin materials were first investigated by laser-induced breakdown spectroscopy, in order to find an asbestos container assuring safe laboratory operation during the material characterization aimed to identify indicators suitable for a quick identification on field. Successively, spectra of asbestos samples of both in serpentine and amphibole forms were measured and the variability in elemental composition was calculated from the emission spectra. Ratios of intensities of characteristic elements were tested as indicators for asbestos recognition. Laser-induced breakdown spectroscopy results were compared with those obtained by analyzing the same asbestos samples with a scanning electron microscopy equipped with an energy dispersive X-ray spectroscopy, a good correlation was found for Mg/Si and Fe/Si, thus showing the capability of laser-induced breakdown spectroscopy as a diagnostic tool for this category of materials. In particular, it was demonstrated that the method based on two indicators derived from laser-induced breakdown spectroscopy intensity ratios allows to discriminate between asbestos and cements in single shot measurements suitable to field operation

  17. A versatile interaction chamber for laser-based spectroscopic applications, with the emphasis on Laser-Induced Breakdown Spectroscopy

    International Nuclear Information System (INIS)

    Novotný, J.; Brada, M.; Petrilak, M.; Prochazka, D.; Novotný, K.; Hrdička, A.; Kaiser, J.

    2014-01-01

    The technical note describes the interaction chamber developed particularly for the laser spectroscopy technique applications, such as Laser-Induced Breakdown Spectroscopy (LIBS), Raman Spectroscopy and Laser-Induced Fluorescence. The chamber was designed in order to provide advanced possibilities for the research in mentioned fields and to facilitate routine research procedures. Parameters and the main benefits of the chamber are described, such as the built-in module for automatic 2D chemical mapping and the possibility to set different ambient gas conditions (pressure value and gas type). Together with the chamber description, selected LIBS application examples benefiting from chamber properties are described. - Highlights: • Development of the interaction chamber for LIBS applications • Example of automated chemical mapping of lead in a chalcopyrite sample • Example of LIBS measurement of fluorine in underpressure • Overview of chamber benefits

  18. Determination of Rare Earth Elements in Geological Samples Using Laser-Induced Breakdown Spectroscopy (LIBS).

    Science.gov (United States)

    Bhatt, Chet R; Jain, Jinesh C; Goueguel, Christian L; McIntyre, Dustin L; Singh, Jagdish P

    2018-01-01

    Laser-induced breakdown spectroscopy (LIBS) was used to detect rare earth elements (REEs) in natural geological samples. Low and high intensity emission lines of Ce, La, Nd, Y, Pr, Sm, Eu, Gd, and Dy were identified in the spectra recorded from the samples to claim the presence of these REEs. Multivariate analysis was executed by developing partial least squares regression (PLS-R) models for the quantification of Ce, La, and Nd. Analysis of unknown samples indicated that the prediction results of these samples were found comparable to those obtained by inductively coupled plasma mass spectrometry analysis. Data support that LIBS has potential to quantify REEs in geological minerals/ores.

  19. CW-laser induced microchannels in dye-polymethacrylic acid films

    OpenAIRE

    M.A. Camacho-López

    2007-01-01

    In this work we report on the formation of microchannels on dye-polymethacrylic acid films using a cw-laser. A focalized beam of a He-Ne laser (632.8 nm emission line) was used to form microchannels on the films. It was found that there exists a laser power density threshold for a pit formation that depends on the dye concentration. The dimensions of the laser-induced channels are dependent on the laser power density. Microchannel formation in the transparent polymethacrylic acid films was no...

  20. Roughness effects on the hydrogen signal in laser-induced breakdown spectroscopy

    DEFF Research Database (Denmark)

    Rapin, W.; Bousquet, B.; Lasue, J.

    2017-01-01

    On Mars, Laser-Induced Breakdown Spectroscopy (LIBS) as performed by the ChemCam instrument can be used to measure the hydrogen content of targets in situ, under a low pressure CO2 atmosphere. However, unexpected variations observed in the Martian dataset suggest an effect related to target...... to hydrogen, as other emission lines in the spectra are not affected. The increase of the signal could be related to an addition of hydrogen to the plasma due to interaction with the surrounding target surface, yet the exact physical process to explain such effect remains to be identified. More generally...

  1. Prospects of real-time single-particle biological aerosol analysis: A comparison between laser-induced breakdown spectroscopy and aerosol time-of-flight mass spectrometry

    International Nuclear Information System (INIS)

    Beddows, D.C.S.; Telle, H.H.

    2005-01-01

    In this paper we discuss the prospects of real-time, in situ laser-induced breakdown spectroscopy applied for the identification and classification of bio-aerosols (including species of potential bio-hazard) within common urban aerosol mixtures. In particular, we address the issues associated with the picking out of bio-aerosols against common background aerosol particles, comparing laser-induced breakdown spectroscopy measurements with data from a mobile single-particle aerosol mass spectrometer (ATOFMS). The data from the latter provide statistical data over an extended period of time, highlighting the variation of the background composition. While single-particle bio-aerosols are detectable in principle, potential problems with small (∼ 1 μm size) bio-aerosols have been identified; constituents of the air mass other than background aerosols, e.g. gaseous CO 2 in conjunction with common background aerosols, may prevent unique recognition of the bio-particles. We discuss whether it is likely that laser-induced breakdown spectroscopy on its own can provide reliable, real-time identification of bio-aerosol in an urban environment, and it is suggested that more than one technique should be or would have to be used. A case for using a combination of laser-induced breakdown spectroscopy and Raman (and/or) laser-induced fluorescence spectroscopy is made

  2. Study of early laser-induced plasma dynamics: Transient electron density gradients via Thomson scattering and Stark Broadening, and the implications on laser-induced breakdown spectroscopy measurements

    International Nuclear Information System (INIS)

    Diwakar, P.K.; Hahn, D.W.

    2008-01-01

    To further develop laser-induced breakdown spectroscopy (LIBS) as an analytical technique, it is necessary to better understand the fundamental processes and mechanisms taking place during the plasma evolution. This paper addresses the very early plasma dynamics (first 100 ns) using direct plasma imaging, light scattering, and transmission measurements from a synchronized 532-nm probe laser pulse. During the first 50 ns following breakdown, significant Thomson scattering was observed while the probe laser interacted with the laser-induced plasma. The Thomson scattering was observed to peak 15-25 ns following plasma initiation and then decay rapidly, thereby revealing the highly transient nature of the free electron density and plasma equilibrium immediately following breakdown. Such an intense free electron density gradient is suggestive of a non-equilibrium, free electron wave generated by the initial breakdown and growth processes. Additional probe beam transmission measurements and electron density measurements via Stark broadening of the 500.1-nm nitrogen ion line corroborate the Thomson scattering observations. In concert, the data support the finding of a highly transient plasma that deviates from local thermodynamic equilibrium (LTE) conditions during the first tens of nanoseconds of plasma lifetime. The implications of this early plasma transient behavior are discussed in the context of plasma-analyte interactions and the role on LIBS measurements

  3. Study of 660 nm laser-induced photoluminescence of chlorophyll-a and its applications

    International Nuclear Information System (INIS)

    Song, Y; Zhang, D X; Zhang, H J

    2007-01-01

    Based on the phenomenon of chlorophyll a photoluminescence, this paper introduces a new method to measure the chlorophyll a content, using 660nm laser diode as a new kind of light source to stimulate fluorescence as well as combining a fiber and spectrum technique. We analyze the characteristics of laser-induced fluorescence spectrum of chlorophyll a and then put forward the new method using two parameters, the relative fluorescence intensity and fluorescence intensity ratio F685/F735, to measure the chlorophyll a content in the water and green leaves respectively. The experimental results indicate that it is completely feasible to give a visual judgment for chlorophyll a content, according to the fluorescence emission spectrum of chlorophyll a. Subsequently, it is verified by three kinds of typical applications. All of these provide a new kind of light source to develop the chlorophyll a fluorometry and further give a technical foundation of on-spot monitoring the chlorophyll a content in the ocean or in green leaves

  4. Laser-induced grating in ZnO

    DEFF Research Database (Denmark)

    Ravn, Jesper N.

    1992-01-01

    A simple approach for the calculation of self-diffraction in a thin combined phase and amplitude grating is presented. The third order nonlinearity, the electron-hole recombination time, and the ambipolar diffusion coefficient in a ZnO crystal are measured by means of laser-induced self-diffracti......A simple approach for the calculation of self-diffraction in a thin combined phase and amplitude grating is presented. The third order nonlinearity, the electron-hole recombination time, and the ambipolar diffusion coefficient in a ZnO crystal are measured by means of laser-induced self...

  5. Ultrafast molecular imaging by laser-induced electron diffraction

    International Nuclear Information System (INIS)

    Peters, M.; Nguyen-Dang, T. T.; Cornaggia, C.; Saugout, S.; Charron, E.; Keller, A.; Atabek, O.

    2011-01-01

    We address the feasibility of imaging geometric and orbital structures of a polyatomic molecule on an attosecond time scale using the laser-induced electron diffraction (LIED) technique. We present numerical results for the highest molecular orbitals of the CO 2 molecule excited by a near-infrared few-cycle laser pulse. The molecular geometry (bond lengths) is determined within 3% of accuracy from a diffraction pattern which also reflects the nodal properties of the initial molecular orbital. Robustness of the structure determination is discussed with respect to vibrational and rotational motions with a complete interpretation of the laser-induced mechanisms.

  6. Determination of a brass alloy concentration composition using calibration-free laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Achouri, M.; Baba-Hamed, T.; Beldjilali, S. A., E-mail: sidahmed.beldjilali@univ-usto.dz; Belasri, A. [Université des Sciences et de la Technologie d’Oran Mohamed Boudiaf USTO-MB, LPPMCA (Algeria)

    2015-09-15

    Laser-induced breakdown spectroscopy (LIBS) is a technique that can provide qualitative and quantitative measurements of the characteristics of irradiated metals. In the present work, we have calculated the parameters of the plasma produced from a brass alloy sample under the action of a pulsed Nd: YAG laser operating at 1064 nm. The emission lines of copper atoms (Cu I), zinc atoms (Zn I), and lead atoms (Pb I), which are elements of a brass alloy composition, were used to investigate the parameters of the brass plasma. The spectral profiles of Cu, Zn, and Pb lines have been used to extract the electron temperature and density of the brass alloy plasma. The characteristics of Cu, Zn, and Pb were determined quantatively by the calibration-free LIBS (CF-LIBS) method considering for accurate analysis that the laser-induced ablated plasma is optically thin in local thermodynamic equilibrium conditions and the plasma ablation is stoichiometric. The Boltzmann plot method was used to evaluate the plasma temperature, and the Stark broadened profiles were used to determine the electron density. An algorithm based on the experimentally measured values of the intensity of spectral lines and the basic laws of plasma physics was developed for the determination of Cu, Zn, and Pb concentrations in the brass sample. The concentrations C{sub CF-LIBS} calculated by CF-LIBS and the certified concentrations C{sub certified} were very close.

  7. New cell line development for antibody-producing Chinese hamster ovary cells using split green fluorescent protein

    Directory of Open Access Journals (Sweden)

    Kim Yeon-Gu

    2012-05-01

    Full Text Available Abstract Background The establishment of high producer is an important issue in Chinese hamster ovary (CHO cell culture considering increased heterogeneity by the random integration of a transfected foreign gene and the altered position of the integrated gene. Fluorescence-activated cell sorting (FACS-based cell line development is an efficient strategy for the selection of CHO cells in high therapeutic protein production. Results An internal ribosome entry site (IRES was introduced for using two green fluorescence protein (GFP fragments as a reporter to both antibody chains, the heavy chain and the light chain. The cells co-transfected with two GFP fragments showed the emission of green fluorescence by the reconstitution of split GFP. The FACS-sorted pool with GFP expression had a higher specific antibody productivity (qAb than that of the unsorted pool. The qAb was highly correlated with the fluorescence intensity with a high correlation coefficient, evidenced from the analysis of median GFP and qAb in individual selected clones. Conclusions This study proved that the fragment complementation for split GFP could be an efficient indication for antibody production on the basis of high correlation of qAb with reconstitution of GFP. Taken together, we developed an efficient FACS-based screening method for high antibody-producing CHO cells with the benefits of the split GFP system.

  8. Development of off-line layer chromatographic and total reflection X-ray fluorescence spectrometric methods for arsenic speciation

    Energy Technology Data Exchange (ETDEWEB)

    Mihucz, Victor G. [Joint Research Group of Environmental Chemistry of Hungarian Academy of Sciences and L. Eoetvoes University, P. O. Box 32, H-1518 Budapest (Hungary); Hungarian Satellite Centre of Trace Elements Institute to UNESCO, P. O. Box 32, H-1518 Budapest (Hungary); Moricz, Agnes M. [L. Eoetvoes University, Department of Chemical Technology and Environmental Chemistry, P.O. Box 32, H-1518 Budapest (Hungary); Kroepfl, Krisztina [Joint Research Group of Environmental Chemistry of Hungarian Academy of Sciences and L. Eoetvoes University, P. O. Box 32, H-1518 Budapest (Hungary); Szikora, Szilvia [Joint Research Group of Environmental Chemistry of Hungarian Academy of Sciences and L. Eoetvoes University, P. O. Box 32, H-1518 Budapest (Hungary); Tatar, Eniko [Hungarian Satellite Centre of Trace Elements Institute to UNESCO, P. O. Box 32, H-1518 Budapest (Hungary); L. Eoetvoes University, Department of Inorganic and Analytical Chemistry, P.O. Box 32, H-1518 Budapest (Hungary); Parra, Lue Meru Marco [Universidad Centro-occidental Lisandro Alvarado, Decanato de Agronomia, Departamento de Quimica y Suelos Unidad de Analisis Instrumental, Apartado Postal 4076, Cabudare 3023 (Venezuela); Zaray, Gyula [Joint Research Group of Environmental Chemistry of Hungarian Academy of Sciences and L. Eoetvoes University, P. O. Box 32, H-1518 Budapest (Hungary) and Hungarian Satellite Centre of Trace Elements Institute to UNESCO, P. O. Box 32, H-1518 Budapest (Hungary) and L. Eoetvoes University, Department of Inorganic and Analytical Chemistry, P.O. Box 32, H-1518 Budapest (Hungary)]. E-mail: zaray@ludens.elte.hu

    2006-11-15

    Rapid and low cost off-line thin layer chromatography-total reflection X-ray fluorescence spectrometry and overpressured thin layer chromatography-total reflection X-ray fluorescence spectrometry methods have been developed for separation of 25 ng of each As(III), As(V), monomethyl arsonic acid and dimethylarsinic acid applying a PEI cellulose stationary phase on plastic sheets and a mixture of acetone/acetic acid/water = 2:1:1 (v/v/v) as eluent system. The type of eluent systems, the amounts (25-1000 ng) of As species applied to PEI cellulose plates, injection volume, development distance, and flow rate (in case of overpressured thin layer chromatography) were taken into consideration for the development of the chromatographic separation. Moreover, a microdigestion method employing nitric acid for the As spots containing PEI cellulose scratched from the developed plates divided into segments was developed for the subsequent total reflection X-ray fluorescence spectrometry analysis. The method was applied for analysis of root extracts of cucumber plants grown in As(III) containing modified Hoagland nutrient solution. Both As(III) and As(V) were detected by applying the proposed thin layer chromatography/overpressured thin layer chromatography-total reflection X-ray fluorescence spectrometry methods.

  9. Development of off-line layer chromatographic and total reflection X-ray fluorescence spectrometric methods for arsenic speciation

    International Nuclear Information System (INIS)

    Mihucz, Victor G.; Moricz, Agnes M.; Kroepfl, Krisztina; Szikora, Szilvia; Tatar, Eniko; Parra, Lue Meru Marco; Zaray, Gyula

    2006-01-01

    Rapid and low cost off-line thin layer chromatography-total reflection X-ray fluorescence spectrometry and overpressured thin layer chromatography-total reflection X-ray fluorescence spectrometry methods have been developed for separation of 25 ng of each As(III), As(V), monomethyl arsonic acid and dimethylarsinic acid applying a PEI cellulose stationary phase on plastic sheets and a mixture of acetone/acetic acid/water = 2:1:1 (v/v/v) as eluent system. The type of eluent systems, the amounts (25-1000 ng) of As species applied to PEI cellulose plates, injection volume, development distance, and flow rate (in case of overpressured thin layer chromatography) were taken into consideration for the development of the chromatographic separation. Moreover, a microdigestion method employing nitric acid for the As spots containing PEI cellulose scratched from the developed plates divided into segments was developed for the subsequent total reflection X-ray fluorescence spectrometry analysis. The method was applied for analysis of root extracts of cucumber plants grown in As(III) containing modified Hoagland nutrient solution. Both As(III) and As(V) were detected by applying the proposed thin layer chromatography/overpressured thin layer chromatography-total reflection X-ray fluorescence spectrometry methods

  10. Laser induced autofluorescence for diagnosis of non-melanoma skin cancer

    Science.gov (United States)

    Drakaki, E.; Makropoulou, M.; Serafetinides, A. A.; Merlemis, N.; Kalatzis, I.; Sianoudis, I. A.; Batsi, O.; Christofidou, E.; Stratigos, A. J.; Katsambas, A. D.; Antoniou, Ch.

    2015-01-01

    Non melanoma skin cancer is one of the most frequent malignant tumors among humans. A non-invasive technique, with high sensitivity and high specificity, would be the most suitable method for basal cell carcinoma (BCC) or other malignancies diagnostics, instead of the well established biopsy and histopathology examination. In the last decades, a non-invasive, spectroscopic diagnostic method was introduced, the laser induced fluorescence (LIF), which could generate an image contrast between different states of skin tissue. The noninvasiveness consists in that this biophotonic method do not require tissue sample excision, what is necessary in histopathology characterization and biochemical analysis of the skin tissue samples, which is worldwide used as an evaluation gold standard. The object of this study is to establish the possibilities of a relatively portable system for laser induced skin autofluorescence to differentiate malignant from nonmalignant skin lesions. Unstained human skin samples, excised from humans undergoing biopsy examination, were irradiated with a Nd:YAG-3ω laser (λ=355 nm, 6 ns), used as an excitation source for the autofluorescence measurements. A portable fiber-based spectrometer was used to record fluorescence spectra of the sites of interest. The ex vivo results, obtained with this spectroscopic technique, were correlated with the histopathology results. After the analysis of the fluorescence spectra of almost 60 skin tissue areas, we developed an algorithm to distinguish different types of malignant lesions, including inflammatory areas. Optimization of the data analysis and potential use of LIF spectroscopy with 355 nm Nd:YAG laser excitation of tissue autofluorescence for clinical applications are discussed.

  11. Laser-induced breakdown spectroscopy for lambda quantification in a direct-injection engine

    International Nuclear Information System (INIS)

    Buschbeck, M.; Büchler, F.; Halfmann, T.; Arndt, S.

    2012-01-01

    We apply laser-induced breakdown spectroscopy (LIBS) to determine local lambda values (i.e. the normalized air-fuel mass ratio) at the ignition location λ ip in a direct-injection single-cylinder optical research engine. The technique enables us to determine variations of λ ip for different fuel injection strategies, as well as correlations between variations in λ ip and the combustion dynamics. In particular we observe, that fluctuations in λ ip are not the major cause of cycle-to-cycle variations in the combustion process. Moreover, our experiments identify insufficient lean λ ip values as a source of misfires in lean combustions. In a combination of LIBS with laser-induced fluorescence (LIF), we obtain additionally information about the two-dimensional λ distribution. These results demonstrate the potential of LIBS to monitor λ values during mixture formation in gasoline engines. - Highlights: ► Determination of λ values by means of LIBS in an optical gasoline engine. ► Evaluation of λ fluctuations for different fuel injection strategies. ► Investigation of the effect of λ upon combustion dynamics. ► Combination of LIBS and LIF to obtain two-dimensional λ distributions.

  12. Prospects for laser-induced breakdown spectroscopy for biomedical applications: a review.

    Science.gov (United States)

    Singh, Vivek Kumar; Rai, Awadhesh Kumar

    2011-09-01

    We review the different spectroscopic techniques including the most recent laser-induced breakdown spectroscopy (LIBS) for the characterization of materials in any phase (solid, liquid or gas) including biological materials. A brief history of the laser and its application in bioscience is presented. The development of LIBS, its working principle and its instrumentation (different parts of the experimental set up) are briefly summarized. The generation of laser-induced plasma and detection of light emitted from this plasma are also discussed. The merit and demerits of LIBS are discussed in comparison with other conventional analytical techniques. The work done using the laser in the biomedical field is also summarized. The analysis of different tissues, mineral analysis in different organs of the human body, characterization of different types of stone formed in the human body, analysis of biological aerosols using the LIBS technique are also summarized. The unique abilities of LIBS including detection of molecular species and calibration-free LIBS are compared with those of other conventional techniques including atomic absorption spectroscopy, inductively coupled plasma atomic emission spectroscopy and mass spectroscopy, and X-ray fluorescence.

  13. Laser Induced Breakdown Spectroscopy in archeometry: A review of its application and future perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Spizzichino, Valeria, E-mail: valeria.spizzichino@enea.it; Fantoni, Roberta

    2014-09-01

    Laser Induced Breakdown Spectroscopy (LIBS) in the last decades has been more and more applied to the field of Cultural Heritage with great results obtained either alone or in combination with complementary laser techniques. Its ability to analyze, with a minimal loss, different kinds of materials in laboratory, in situ and even in hostile environments has been highly appreciated. The main aim of this paper is to present a review of LIBS applications in the interdisciplinary field of archeometry. The LIBS technique is shortly described both from a theoretical and practical point of view, discussing the instrumental setup, also in comparison with typical features of laser induced fluorescence (LIF) and Raman spectroscopy apparata. The complementary with multivariate analysis, a method that can help in reducing data set dimensions and in pulling out effective information, is stressed. In particular the role of LIBS in Cultural Heritage material characterization, recognition of fakes and indirect dating is described, reporting general considerations and case studies on metal alloys, mural paintings, decorated ceramics, glasses, stones and gems. - Highlights: • Applications of LIBS to archeometry are reviewed. • Complementary among LIBS, LIF, Raman and multivariate analysis is highlighted. • Three major areas of successful LIBS application in archeometry are identified. • Significant results have been presented for several different materials.

  14. Laser Induced Breakdown Spectroscopy in archeometry: A review of its application and future perspectives

    Science.gov (United States)

    Spizzichino, Valeria; Fantoni, Roberta

    2014-09-01

    Laser Induced Breakdown Spectroscopy (LIBS) in the last decades has been more and more applied to the field of Cultural Heritage with great results obtained either alone or in combination with complementary laser techniques. Its ability to analyze, with a minimal loss, different kinds of materials in laboratory, in situ and even in hostile environments has been highly appreciated. The main aim of this paper is to present a review of LIBS applications in the interdisciplinary field of archeometry. The LIBS technique is shortly described both from a theoretical and practical point of view, discussing the instrumental setup, also in comparison with typical features of laser induced fluorescence (LIF) and Raman spectroscopy apparata. The complementary with multivariate analysis, a method that can help in reducing data set dimensions and in pulling out effective information, is stressed. In particular the role of LIBS in Cultural Heritage material characterization, recognition of fakes and indirect dating is described, reporting general considerations and case studies on metal alloys, mural paintings, decorated ceramics, glasses, stones and gems.

  15. Analysis of copper contamination in transformer insulating material with nanosecond- and femtosecond-laser-induced breakdown spectroscopy

    Science.gov (United States)

    Aparna, N.; Vasa, N. J.; Sarathi, R.

    2018-06-01

    This work examines the oil-impregnated pressboard insulation of high-voltage power transformers, for the determination of copper contamination. Nanosecond- and femtosecond-laser-induced breakdown spectroscopy revealed atomic copper lines and molecular copper monoxide bands due to copper sulphide diffusion. X-ray diffraction studies also indicated the presence of CuO emission. Elemental and molecular mapping compared transformer insulating material ageing in different media—air, N2, He and vacuum.

  16. Towards friction control using laser-induced periodic surface structures

    NARCIS (Netherlands)

    Eichstädt, J.; Römer, Gerardus Richardus, Bernardus, Engelina; Huis in 't Veld, Bert; Schmidt, M.; Zaeh, M.

    2011-01-01

    This paper aims at contributing to the study of laser-induced periodic surface structures (LIPSS) and the description of their tribological properties in order to facilitate the knowledge for contact mechanical applications. To obtain laser parameters for LIPSS formation, we propose to execute two

  17. Overview of applications of Laser-Induced Breakdown Spectroscopy (LIBS)

    International Nuclear Information System (INIS)

    Cremers, D.A.

    1987-01-01

    Laser-induced breakdown spectroscopy (LIBS) is a method of performing elemental analyses of solids, liquids, and gases using the microplasma produced by a focused laser pulse. Because the microplasma is formed by optical radiation, LIBS has some important advantages compared to conventional laboratory based analytical methods. Three applications are discussed which use the LIBS method. 6 refs., 8 figs., 2 tabs

  18. Measurement of gas flow velocities by laser-induced gratings

    Energy Technology Data Exchange (ETDEWEB)

    Hemmerling, B; Stampanoni-Panariello, A [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Kozlov, A D.N. [General Physics Institute, Moscow (Russian Federation)

    1999-08-01

    Time resolved light scattering from laser-induced electrostrictive gratings was used for the determination of flow velocities in air at room temperature. By measuring the velocity profile across the width of a slit nozzle we demonstrated the high spatial resolution (about 200 mm) of this novel technique. (author) 3 figs., 1 ref.

  19. Calibration-free laser-induced breakdown spectroscopy for ...

    Indian Academy of Sciences (India)

    journal of. August 2012 physics pp. 299–310. Calibration-free laser-induced ... for quantitative analysis of materials, illustrated by CF-LIBS applied to a ..... The authors are thankful to BRNS, DAE, Govt. of India for the financial support provided.

  20. Laser-induced incandescence applied to dusty plasmas

    NARCIS (Netherlands)

    van de Wetering, F.M.J.H.; Oosterbeek, W.; Beckers, J.; Nijdam, S.; Kovacevic, E.; Berndt, J.

    2016-01-01

    This paper reports on the laser heating of nanoparticles (diameters ≤1 μm) confined in a reactive plasma by short (150 ps) and intense (~63 mJ) UV (355 nm) laser pulses (laser-induced incandescence, LII). Important parameters such as the particle temperature and radius follow from analysis of the

  1. Laser induced damage threshold on metallic surfaces during laser cleaning

    CSIR Research Space (South Africa)

    Labuschagne, K

    2005-07-01

    Full Text Available laser paint removal. Laser induced damage on 316L stainless steel was studied, with the target subjected to single and multiple pulse irradiations using a Q-switched Nd:YAG, with fluences between 0.15 and 11.8 J/cm2. Several different damage morphologies...

  2. Erratum to: Measurement of copper vapour laser-induced ...

    Indian Academy of Sciences (India)

    Erratum to: Measurement of copper vapour laser-induced deformation of dielectric-coated mirror surface by. Michelson interferometer. A WAHID. ∗. , S KUNDU, J S B SINGH, A K SINGH, A KHATTAR,. S K MAURYA, J S DHUMAL and K DASGUPTA. Laser & Plasma Technology Division, Beam Technology Development ...

  3. Continuous monitoring of bisulfide variation in microdialysis effluents by on-line droplet-based microfluidic fluorescent sensor.

    Science.gov (United States)

    Zhu, Xiaocui; Xu, Lei; Wu, Tongbo; Xu, Anqin; Zhao, Meiping; Liu, Shaorong

    2014-05-15

    We demonstrate a novel fluorescent sensor for real-time and continuous monitoring of the variation of bisulfide in microdialysis effluents by using a nanoparticle-glutathione-fluorescein isothiocyanate (AuNP-GSH-FITC) probe coupled with on-line droplet-based microfluidic chip. The AuNP-GSH-FITC fluorescent probe was firstly developed and used for bisulfide detection in bulk solution by quantitative real-time PCR, which achieved a linear working range from 0.1 μM to 5.0 μM and a limit of detection of ~50 nM. The response time was less than 2 min. With the aid of co-immobilized thiol-polyethylene glycol, the probe exhibited excellent stability and reproducibility in high salinity solutions, including artificial cerebrospinal fluids (aCSF). By adding 0.1% glyoxal to the probe solution, the assay allowed quantification of bisulfide in the presence of cysteine at the micro-molarity level. Using the AuNP-GSH-FITC probe, a droplet-based microfluidic fluorescent sensor was further constructed for online monitoring of bisulfide variation in the effluent of microdialysis. By using fluorescence microscope-charge-coupled device camera as the detector, the integrated microdialysis/microfluidic chip device achieved a detection limit of 2.0 μM and a linear response from 5.0 μM to 50 μM for bisulfide in the tested sample. The method was successfully applied for the on-line measurement of bisulfide variation in aCSF and serum samples. It will be a very useful tool for tracking the variation of bisulfide or hydrogen sulfide in extracellular fluids. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Applications of MODIS Fluorescent Line Height Measurements to Monitor Water Quality Trends and Algal Bloom Activity

    Science.gov (United States)

    Fischer, Andrew; Moreno-Mardinan, Max; Ryan, John P.

    2012-01-01

    Recent advances in satellite and airborne remote sensing, such as improvements in sensor and algorithm calibrations, processing techniques and atmospheric correction procedures have provided for increased coverage of remote-sensing, ocean-color products for coastal regions. In particular, for the Moderate Resolution Imaging Spectrometer (MODIS) sensor calibration updates, improved aerosol retrievals and new aerosol models has led to improved atmospheric correction algorithms for turbid waters and have improved the retrieval of ocean color in coastal waters. This has opened the way for studying ocean phenomena and processes at finer spatial scales, such as the interactions at the land-sea interface, trends in coastal water quality and algal blooms. Human population growth and changes in coastal management practices have brought about significant changes in the concentrations of organic and inorganic, particulate and dissolved substances entering the coastal ocean. There is increasing concern that these inputs have led to declines in water quality and have increase local concentrations of phytoplankton, which cause harmful algal blooms. In two case studies we present MODIS observations of fluorescence line height (FLH) to 1) assess trends in water quality for Tampa Bay, Florida and 2) illustrate seasonal and annual variability of algal bloom activity in Monterey Bay, California as well as document estuarine/riverine plume induced red tide events. In a comprehensive analysis of long term (2003-2011) in situ monitoring data and satellite imagery from Tampa Bay we assess the validity of the MODIS FLH product against chlorophyll-a and a suite of water quality parameters taken in a variety of conditions throughout a large optically complex estuarine system. A systematic analysis of sampling sites throughout the bay is undertaken to understand how the relationship between FLH and in situ chlorophyll-a responds to varying conditions and to develop a near decadal trend in

  5. Investigation on the spatial evolution of the emission spectra in laser-induced Ni plasmas

    International Nuclear Information System (INIS)

    Du Chuanmei; Xu Ying; Zhang Mingxu

    2012-01-01

    In this paper, the spatial resolved emission spectrum of Ni atom in laser induced Ni plasma is measured in the wavelength region from 350 nm to 600 nm. The spatial evolution of the relative intensities and the Stark broadening of the 385.83 nm emission spectrum lines are also obtained. It is shown that Stark broadening and intensity of the spectrum lines increases firstly to its maximum and then de- creases along the direction of laser beam when the distance from the target surface is in the range from 0 to 2.5 mm. The maximum value of Stark broadening and relative intensity of the spectrum lines appear at 1.5 mm from the target surface. (authors)

  6. Cluster analysis of polymers using laser-induced breakdown spectroscopy with K-means

    Science.gov (United States)

    Yangmin, GUO; Yun, TANG; Yu, DU; Shisong, TANG; Lianbo, GUO; Xiangyou, LI; Yongfeng, LU; Xiaoyan, ZENG

    2018-06-01

    Laser-induced breakdown spectroscopy (LIBS) combined with K-means algorithm was employed to automatically differentiate industrial polymers under atmospheric conditions. The unsupervised learning algorithm K-means were utilized for the clustering of LIBS dataset measured from twenty kinds of industrial polymers. To prevent the interference from metallic elements, three atomic emission lines (C I 247.86 nm , H I 656.3 nm, and O I 777.3 nm) and one molecular line C–N (0, 0) 388.3 nm were used. The cluster analysis results were obtained through an iterative process. The Davies–Bouldin index was employed to determine the initial number of clusters. The average relative standard deviation values of characteristic spectral lines were used as the iterative criterion. With the proposed approach, the classification accuracy for twenty kinds of industrial polymers achieved 99.6%. The results demonstrated that this approach has great potential for industrial polymers recycling by LIBS.

  7. Bioanalytical Applications of Fluorescence Line-Narrowing and Non-Line-Narrowing Spectroscopy Interfaced with Capillary Electrophoresis and High-Performance Liquid Chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Kenneth Paul [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    Capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC) are widely used analytical separation techniques with many applications in chemical, biochemical, and biomedical sciences. Conventional analyte identification in these techniques is based on retention/migration times of standards; requiring a high degree of reproducibility, availability of reliable standards, and absence of coelution. From this, several new information-rich detection methods (also known as hyphenated techniques) are being explored that would be capable of providing unambiguous on-line identification of separating analytes in CE and HPLC. As further discussed, a number of such on-line detection methods have shown considerable success, including Raman, nuclear magnetic resonance (NMR), mass spectrometry (MS), and fluorescence line-narrowing spectroscopy (FLNS). In this thesis, the feasibility and potential of combining the highly sensitive and selective laser-based detection method of FLNS with analytical separation techniques are discussed and presented. A summary of previously demonstrated FLNS detection interfaced with chromatography and electrophoresis is given, and recent results from on-line FLNS detection in CE (CE-FLNS), and the new combination of HPLC-FLNS, are shown.

  8. Detection and evaluation of uranium in different minerals by gamma spectrometry and laser induced breakdown spectroscopy

    International Nuclear Information System (INIS)

    Sergani, F.M.; Khedr, M.A.; Harith, M.A.; El Mongy, S.A.

    2004-01-01

    Analysis, detection and evaluation of source nuclear materials (e.g. uranium) in different minerals by sensitive techniques are a vital objective for uranium exploration, nuclear materials extraction, processing and verification. In this work, uranium in different geological formations was determined using gamma spectrometry and laser induced breakdown spectroscopy (LIBS). The investigated samples were collected from different regions distributed all over Egypt. The samples were then prepared for non-destructive analysis. A hyper pure germanium detector was used to measure the emitted gamma rays of uranium and its daughters in the samples. The concentrations of uranium in ppm (μg/g) in the investigated samples are given and discussed in this work. The highest uranium concentration (4354.9 ppm) was found in uranophane samples of Gattar rocks. In Laser induced breakdown spectroscopy (LIBS) technique, plasma was formed by irradiating the rock surface with focused Q-switched Nd:Yag laser pulses of 7 ns pulse duration at the fundamental wavelength (1064 nm). Atoms and ions originating from the rock surface are excited and ionized in the laser produced hot plasma (∝10 000 K). The plasma emission spectral line is characteristic of the elements present in the plasma and allows identification of the uranium in the uranophane mineral. The strong atomic line at 424.2 nm is used for the qualitative identification of uranium. It can be mentioned that the elevated levels of uranium in some of the investigated uranophane samples are of great economic feasibility to be extracted. (orig.)

  9. Laser-induced flourescence studies of Cm3+ complexes in solution

    International Nuclear Information System (INIS)

    Beitz, J.V.

    1989-01-01

    Photophysical studies of complexed Cm 3 + in solution have been carried out using a laser-induced fluorescence method. The luminescence decay rate of the first excited J=7/2 state of Cm 3 + was measured using carbonate, nitrate, and two extractant aminocarboxylic acids as complexing ligands in aqueous solution. Cm(ClO 4 ) 3 dissolved in methyl sulfoxide also was studied. Solvent deuteration provided insight into the dominant nonradiative luminescence quenching mechanism which was found to be electronic-to- vibrational energy transfer. Emission spectra of Cm 3 + complexed by the various ligands studied are reported. Prior spectroscopic and photophysical studies of Cm 3 + in solution are reviewed. 24 refs. , 2 figs., 1 tab

  10. Transition probability of the 5971-A line in neutral uranium from collision-induced fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Gagne, J.M.; Mongeau, B.; Demers, Y.; Pianarosa, P.

    1981-01-01

    From collision-induced fluorescence spectroscopy measurements, we have determined the transition probability Aof the 5971-A transition in neutral uranium. Our value, A 5971 = (5.9 +- 1.8) x 10 5 sec -1 , is, within experimental error, in good agreement with the previous determination of Corliss, A 5971 = (7.3 +- 3.0) x 10 5 sec -1 [J. Res. Nat. Bur. Stand. Sect. A 80,1 (1976)

  11. Transformation of the rodent malaria parasite Plasmodium chabaudi and generation of a stable fluorescent line PcGFPCON

    Directory of Open Access Journals (Sweden)

    Reece Sarah E

    2008-09-01

    Full Text Available Abstract Background The rodent malaria parasite Plasmodium chabaudi has proven of great value in the analysis of fundamental aspects of host-parasite-vector interactions implicated in disease pathology and parasite evolutionary ecology. However, the lack of gene modification technologies for this model has precluded more direct functional studies. Methods The development of in vitro culture methods to yield P. chabaudi schizonts for transfection and conditions for genetic modification of this rodent malaria model are reported. Results Independent P. chabaudi gene-integrant lines that constitutively express high levels of green fluorescent protein throughout their life cycle have been generated. Conclusion Genetic modification of P. chabaudi is now possible. The production of genetically distinct reference lines offers substantial advances to our understanding of malaria parasite biology, especially interactions with the immu